JP4477385B2 - Thermoplastic elastomer composition - Google Patents

Description

The present invention relates to a thermoplastic elastomer composition, and relates to a thermoplastic elastomer composition having excellent mechanical properties, oil resistance, heat resistance, and compression set properties while having low hardness and flexibility.

Conventionally, as a polymer material having elasticity, a material obtained by blending a rubber such as natural rubber or synthetic rubber with a crosslinking agent or a reinforcing agent and crosslinking under high temperature and high pressure has been widely used. However, such rubbers require a process of crosslinking and molding for a long time under high temperature and pressure, and are inferior in processability. Moreover, since the crosslinked rubber does not exhibit thermoplasticity, it is generally impossible to perform recycle molding like a thermoplastic resin. For this reason, various thermoplastic elastomers have been developed in recent years that can be easily produced using general-purpose melt molding techniques such as hot press molding, injection molding, and extrusion molding in the same way as ordinary thermoplastic resins. ing. As such thermoplastic elastomers, various types of polymers such as olefins, urethanes, esters, styrenes, and vinyl chlorides have been developed and are commercially available.

Furthermore, in recent years, a new thermoplastic elastomer has also been developed, and an acrylic block body having a methacryl block and an acrylic block is disclosed (for example, see Patent Document 1). Further, the acrylic block body has a feature that it is excellent in weather resistance, heat resistance and oil resistance.

On the other hand, the elastic modulus and hardness of the rubber material are appropriately set according to the purpose of use. The reduction in hardness of the material can be usually achieved by using a plasticizer, but there are problems such as volatilization under the conditions of use of the plasticizer and contamination due to bleed out of the plasticizer.

In addition to this, when a general ester plasticizer or the like is used in the acrylic block body, dissolution of the methacryl block also proceeds, and there is a concern that heat resistance is reduced.
Therefore, it has been required to obtain a thermoplastic elastomer composition capable of low hardness while maintaining heat resistance.

Japanese Patent No. 2553134

An object of the present invention is to provide a low-hardness thermoplastic elastomer composition having heat resistance.

As a result of intensive studies by the present inventors, a block copolymer (A) containing a methacrylic polymer block (a) and an acrylic polymer block (b), and (meth) acrylic obtained by controlled polymerization It has been found that the above-mentioned problems can be solved by a thermoplastic elastomer composition comprising a polymer (B) and having a specific composition ratio (A) or (B).

That is, the present invention relates to a block copolymer (A) containing a methacrylic polymer block (a) and an acrylic polymer block (b), and a (meth) acrylic polymer obtained by controlled polymerization. It relates to a thermoplastic elastomer composition comprising (B) and having a weight ratio of (A) :( B) = 95: 5 to 50:50.

The present invention also provides:
The block copolymer (A) has the general formula b- (ab) _r , general formula (ab) _r -a
Wherein the thermoplastic elastomer composition is at least one selected from the group consisting of block copolymers represented by the formula:
The thermoplastic elastomer composition as described above, wherein the (meth) acrylic polymer (B) comprises an ab diblock copolymer containing a methacrylic polymer block (a) and an acrylic polymer block (b);
At least 50% by weight of the monomer constituting the acrylic polymer block (b) contained in the block copolymer (A) and at least 50% by weight of the monomer constituting the (meth) acrylic polymer (B) The above-mentioned thermoplastic elastomer composition, which is the same compound;
The monomers constituting the acrylic polymer block (b) and the (meth) acrylic polymer (B) are each composed of ethyl acrylate, n-butyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate. The thermoplastic elastomer composition which is at least one monomer selected from the group;
In the main chain of at least one of the methacrylic polymer block (a) and the acrylic polymer block (b), the general formula (1):

(Wherein R ¹ represents a hydrogen atom or a methyl group, and may be the same or different from each other. N represents an integer of 0 to 3, and m represents an integer of 0 or 1). The thermoplastic elastomer composition having a group (c) and / or a carboxyl group (d);
The above-mentioned thermoplastic elastomer composition, wherein the block copolymer (A) is obtained by atom transfer radical polymerization;
The thermoplastic elastomer composition, wherein the (meth) acrylic polymer (B) is obtained by atom transfer radical polymerization;
The above-mentioned thermoplastic elastomer composition, wherein the atom transfer radical polymerization uses a copper complex as a catalyst;
About.

The thermoplastic elastomer composition of the present invention will be described below.
The thermoplastic elastomer composition of the present invention is a block copolymer (A) containing a methacrylic polymer block (a) and an acrylic polymer block (b), and (meth) obtained by controlled polymerization. It consists of an acrylic polymer (B) and satisfies the weight ratio of (A) :( B) = 95: 5 to 50:50.
Each component will be described below.

<< Block copolymer (A) >>
The block copolymer (A) in the present invention comprises a methacrylic polymer block (a) and an acrylic polymer block (b).
Further, the structure of the block copolymer (A) is preferably a linear block copolymer or a branched (star) block copolymer, and may be a mixture thereof. The structure of such a block copolymer is required for the required physical properties of the block copolymer (A) and the composition of the block copolymer (A) and the (meth) acrylic polymer (B). The processing properties and mechanical properties to be used can be properly used as necessary, but from the viewpoint of cost and ease of polymerization, a linear block copolymer is preferable.

From the viewpoint of physical properties of the composition, the linear block copolymer is represented by the general formula b- (a-) when the methacrylic polymer block (a) is expressed as a and the acrylic polymer block (b) is expressed as b. b) at least selected from the group consisting of block copolymers represented by _r , (ab) _r- a, ab- (ab) _r (wherein r is an integer of 1 or more). One type of block copolymer is preferred. Moreover, at least 1 sort (s) selected from the group which consists of a block copolymer represented by general formula b- (ab) _r , (ab) _r- a (wherein r is an integer greater than or equal to 1). The block copolymer is more preferable. Among these, an aba type triblock copolymer is particularly preferable from the viewpoint of easy handling during processing and physical properties of the composition.

The block copolymer (A) of the present invention is used when the thermoplastic elastomer composition obtained requires higher heat resistance and cohesion, or when the block copolymer (A) and (meth) acrylic polymer are used. When it is necessary to improve the compatibility with the polymer (B), an acid anhydride group (c) and / or a carboxyl group (d) can be introduced. When higher heat resistance is required, it is preferable to introduce a carboxyl group (d). Moreover, it is preferable to introduce | transduce an acid anhydride group (c) from the point of the workability of the thermoplastic elastomer composition obtained, and the ease of superposition | polymerization of a block copolymer (A).

The acid anhydride group (c) and / or the carboxyl group (d) can be one or more per polymer block, and in the case of two or more, the monomer is polymerized. The manner in which it is present can be random copolymerization or block copolymerization.
For example, an aba type triblock copolymer is represented by (a / z) -ba type, (a / z) -b- (a / z) type, zab- a-type, za-b-a-z type, a- (b / z) -a-type, a-b-za-type, a-z-b-za-type, (a / z) -(B / z)-(a / z) type, etc. may be sufficient.
Here, z represents a monomer or polymer block containing an acid anhydride group (c) and / or a carboxyl group (d), and (a / z) means an acid anhydride group (c ) And / or a monomer containing a carboxyl group (d) is copolymerized, and (b / z) is an acid anhydride group (c) and / or a carboxyl group (d) in the block b. It represents that the monomer containing is copolymerized.
Further, in a or b, the part containing z and the form contained may be freely set, and can be properly used according to the purpose.

The number average molecular weight of the block copolymer (A) in the present invention may be determined from the molecular weights required for the methacrylic polymer block (a) and the acrylic polymer block (b), respectively, and is not particularly limited. . The number average molecular weight of the block copolymer (A) is preferably from 30,000 to 500,000, more preferably from 40,000 to 400,000, still more preferably from 50,000 to 300,000. If the number average molecular weight is less than 30000, sufficient mechanical properties as an elastomer tend to be difficult to develop. Conversely, if the number average molecular weight exceeds 500000, the processing characteristics may deteriorate.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of the block copolymer (A) in the present invention is 1 to 1.8. It is preferable that it is 1 to 1.5. When Mw / Mn exceeds 1.8, the uniformity of the block copolymer (A) may be lowered.

The composition ratio of the methacrylic polymer block (a) and the acrylic polymer block (b) constituting the block copolymer (A) is required for physical properties required in the application to be used and when the composition is processed. What is necessary is just to determine from the moldability and the molecular weight required for each of the methacrylic polymer block (a) and the acrylic polymer block (b).
Although it does not specifically limit as a composition ratio, It is preferable that a methacrylic polymer block (a) is 5 to 80 weight%, and an acrylic polymer block (b) is 95 to 20 weight%. More preferably, the methacrylic polymer block (a) is 10 to 70% by weight, the acrylic polymer block (b) is 90 to 30% by weight, and more preferably the methacrylic polymer block (a). It is 20 to 60% by weight, and the acrylic polymer block (b) is 80 to 40% by weight. When the proportion of the methacrylic polymer block (a) is less than 5% by weight, the rubber elasticity at high temperature tends to decrease, and when the proportion of (a) exceeds 80% by weight, mechanical properties as an elastomer are obtained. In particular, the elongation at break tends to decrease, the flexibility of the resulting thermoplastic elastomer composition tends to decrease, and the hardness tends to increase.

The relationship between the glass transition temperatures of the methacrylic polymer block (a) and the acrylic polymer block (b) constituting the block copolymer (A) in the present invention is the glass of the methacrylic polymer block (a). When the transition temperature is Tg _a and the glass transition temperature of the acrylic polymer block (b) is Tg _b , it is preferable to satisfy the relationship of the following formula.
Tg _a > Tg _b

The glass transition temperature (Tg) of the polymer can be set by roughly setting the weight ratio of the monomer of each polymer portion according to the following Fox formula.
_{1 / Tg = (W 1 /} Tg 1) + (W 2 / Tg 2) + ... + (W m / Tg m)
W ₁ + W ₂ + ... + W _m = 1
In the formula, Tg represents the glass transition temperature of the polymer portion, and Tg ₁ , Tg ₂ ,..., Tg _m represent the glass transition temperature of each polymerization monomer. W ₁ , W ₂ ,..., W _m represent the weight ratio of each polymerization monomer.

As the glass transition temperature of each polymerization monomer in the Fox formula, for example, the value described in Polymer Handbook Third Edition (Wiley-Interscience, 1989) may be used.
The glass transition temperature can be measured by DSC (differential scanning calorimetry) or tan δ peak of dynamic viscoelasticity.

<Methacrylic polymer block (a)>
The monomer constituting the methacrylic polymer block (a) is a methacrylic acid ester monomer from the viewpoint of easily obtaining a block copolymer (A) having desired physical properties, cost and availability. And other vinyl monomers copolymerizable therewith.
Moreover, the monomer which has an acid anhydride group (c) and / or a carboxyl group (d) may be included as a methacrylic acid ester monomer.

Examples of the methacrylic acid ester monomer constituting the methacrylic polymer block (a) include, for example, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, methacryl Isobutyl acid, n-pentyl methacrylate, n-hexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, methacryl Methacrylic acid aliphatic hydrocarbon (eg alkyl) esters such as dodecyl acid and stearyl methacrylate; Cycloacrylic acid alicyclic hydrocarbons such as cyclohexyl methacrylate and isobornyl methacrylate; benzyl methacrylate and methacrylic acid Acid α-methylbenzyl Methacrylic acid aralkyl esters such as α, α-dimethylbenzyl methacrylate; methacrylic aromatic hydrocarbon esters such as phenyl methacrylate and tolyl methacrylate; 2-methoxyethyl methacrylate, methacrylic acid 3- Esters of methacrylic acid such as methoxybutyl and functional group-containing alcohols having etheric oxygen; trifluoromethyl methacrylate, 2-trifluoroethyl methacrylate, 2-perfluoroethylethyl methacrylate, methacrylic acid 2-perfluoroethyl-2-perfluorobutylethyl, 2-perfluoroethyl methacrylate, perfluoromethyl methacrylate, diperfluoromethyl methyl methacrylate, 2-perfluoromethyl-2-par methacrylate Fluoroethylmethyl , Methacrylic acid 2-perfluorohexylethyl, meta 2- perfluorodecyl acrylate, methacrylic acid fluorinated alkyl esters such as meta 2- perfluoro-hexadecyl acrylate, and the like.
At least one of these can be used.
Among these, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, and n-methacrylate in terms of cost and availability and mechanical properties of the resulting thermoplastic elastomer composition. Butyl is preferred, and methyl methacrylate is particularly preferred.

Examples of the vinyl monomer copolymerizable with the methacrylic acid ester monomer constituting the methacrylic polymer block (a) include acrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, and conjugated dienes. Examples of such compounds include halogenated unsaturated compounds, unsaturated carboxylic acid compounds, unsaturated dicarboxylic acid compounds, vinyl ester compounds, and maleimide compounds.

Examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, N-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, and other aliphatic acrylates (eg alkyl) esters; cyclohexyl acrylate, isobornyl acrylate, etc. Acrylic alicyclic hydrocarbon ester; Acrylic aromatic hydrocarbon ester such as phenyl acrylate and tolyl acrylate; Aralkyl acrylate such as benzyl acrylate, α-methylbenzyl acrylate, α, α-dimethylbenzyl acrylate, etc. Ter; ester of 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, etc. and functional group-containing alcohol having etheric oxygen; trifluoromethyl methyl acrylate, 2-trifluoromethyl ethyl acrylate, acrylic 2-perfluoroethylethyl acid, 2-perfluoroethyl-2-perfluorobutylethyl acrylate, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethyl methyl acrylate, 2-peracrylate Examples include fluoroalkyl esters of acrylic acid such as fluoromethyl-2-perfluoroethylmethyl, 2-perfluorohexylethyl acrylate, 2-perfluorodecylethyl acrylate, 2-perfluorohexadecylethyl acrylate, and the like. Can .

Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, and the like.
Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.
Examples of the conjugated diene compound include butadiene and isoprene.
Examples of the halogen-containing unsaturated compound include vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoropropylene, and vinylidene fluoride.

Examples of the unsaturated carboxylic acid compound include methacrylic acid and acrylic acid.
Examples of the unsaturated dicarboxylic acid compound include maleic anhydride, maleic acid, monoalkyl esters and dialkyl esters of maleic acid, fumaric acid, monoalkyl esters and dialkyl esters of fumaric acid, and the like.
Examples of the vinyl ester compound include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate, and the like.
Examples of the maleimide compound include maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide and the like.

At least one of these vinyl monomers can be used. Moreover, a preferable thing can be selected for these vinyl monomers by compatibility with the (meth) acrylic polymer (B).

In addition, methyl methacrylate polymer is almost quantitatively depolymerized by thermal decomposition, but in order to suppress it, acrylic acid esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid 2-methoxyethyl or a mixture thereof, styrene or the like can be copolymerized. Further, acrylonitrile can be copolymerized for the purpose of improving oil resistance.

Here, the ratio of the methacrylic acid ester monomer is preferably 50% by weight or more, and more preferably 75% by weight or more in the whole methacrylic polymer block (a). If it is less than 50% by weight, the weather resistance, high glass transition point, compatibility with the resin, etc., which are characteristics of the methacrylic acid ester, tend to be impaired. The proportion of the other copolymerizable vinyl monomer is preferably 0 to 50% by weight, more preferably 0 to 25% by weight in the whole (a).

The molecular weight required for the methacrylic polymer block (a) may be determined from the cohesive force required for the methacrylic polymer block (a) and the time required for the polymerization.

The cohesive force is said to depend on the interaction between molecules and the degree of entanglement, and as the molecular weight increases, the entanglement point increases and the cohesive force increases. That is, the molecular weight required for the methacrylic polymer block (a) and M _a, when the methacrylic polymer block (a) a polymer of the entanglement molecular weight constituting the and Mc _a, cohesion If necessary, preferably M _a> Mc a, when the additional cohesion is required, preferably M _a> 2Mc a, conversely, when it is desired to achieve both a degree of cohesion and creep resistance , Mc _a <M _a <2Mc _a is preferred. The molecular weight between the entanglement points may be referred to Wu et al. (Polymer. Eng. And Sci., 1990, Vol. 30, p. 753).

For example, if the methacrylic polymer block (a) is entirely composed of methyl methacrylate, in the case where cohesion is required, the number average molecular weight of the methacrylic polymer block (a) is: It is preferably 9200 or more. Moreover, since there exists a tendency for polymerization time to become long when a number average molecular weight is large, what is necessary is just to set according to required productivity, Preferably it is 200000 or less, More preferably, it is 100000 or less. However, when the acid anhydride group (c) and / or the carboxyl group (d) is contained in the methacrylic polymer block (a), aggregation by the acid anhydride group (c) and / or the carboxyl group (d) Since force is applied, the number average molecular weight can be set lower.

Furthermore, the glass transition temperature (Tg _a ) of the methacrylic polymer block (a) is preferably 100 ° C. or higher, more preferably 110 ° C. or higher. When the glass transition temperature is less than 100 ° C., rubber elasticity at high temperatures tends to decrease.
The setting of Tg _a of the methacrylic polymer block (a) in accordance with said Fox equation, can be performed by setting the weight ratio of the monomers of each polymer portion.

<Acrylic polymer block (b)>
The monomer composing the acrylic polymer block (b) is an acrylate monomer, and can be copolymerized with it from the viewpoint of easily obtaining a composition having desired physical properties, cost and availability. It is preferably made of a new vinyl monomer.
Moreover, the monomer which has an acid anhydride group (c) and / or a carboxyl group (d) may be included as an acrylate ester monomer.

The acrylic ester monomer constituting the acrylic polymer block (b) is a vinyl monomer copolymerizable with the methacrylic ester monomer constituting the methacrylic polymer block (a). The same specific example as an acrylic ester monomer can be given. In addition, at least one of these can be used.

Among these acrylate monomers, ethyl acrylate, n-butyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate are preferable.
More specifically, n-butyl acrylate is preferable in terms of impact resistance, cost, and availability of the thermoplastic elastomer composition. Further, when the composition needs oil resistance, ethyl acrylate is preferable. Moreover, when low temperature characteristics and flexibility are required, or when lower hardness characteristics are required, 2-ethylhexyl acrylate is preferable. Furthermore, when it is desired to achieve both oil resistance and low temperature characteristics, a mixture of ethyl acrylate, n-butyl acrylate, and 2-methoxyethyl acrylate is preferable.

Examples of vinyl monomers copolymerizable with the acrylate monomer constituting the acrylic polymer block (b) include, for example, methacrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, and conjugated dienes. Examples include compounds, halogen-containing unsaturated compounds, unsaturated carboxylic acid compounds, unsaturated dicarboxylic acid compounds, vinyl ester compounds, maleimide compounds, and the like.

Specific examples of methacrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, halogen-containing unsaturated compounds, unsaturated carboxylic acid compounds, unsaturated dicarboxylic acid compounds, vinyl ester compounds, and maleimide compounds Are the same as the specific examples in the methacrylic polymer block (a). It is preferable to use at least one of these.
These vinyl monomers include glass transition temperature, elastic modulus, polarity required for the acrylic polymer block (b), physical properties required for the composition, (meth) acrylic polymer (B) and Preferred ones can be selected depending on the compatibility of the two.

Here, the ratio of the acrylate monomer is preferably 50% by weight or more, and more preferably 70% by weight or more in the whole acrylic polymer block (b). If it is less than 50% by weight, the physical properties of the composition, particularly impact resistance and flexibility, which are characteristics when using an acrylic ester, tend to be impaired. Moreover, 0-50 weight% is preferable and, as for the ratio of the other vinyl-type monomer which can be copolymerized, More preferably, it is 0-25 weight%.

The molecular weight required for the acrylic polymer block (b) may be determined from the elastic modulus and rubber elasticity required for the acrylic polymer block (b), the time required for the polymerization, and the like.

The elastic modulus is closely related to the ease of movement of the molecular chain and its molecular weight, and the original elastic modulus is not shown unless the molecular weight exceeds a certain level. The same applies to rubber elasticity, but from the viewpoint of rubber elasticity, a larger molecular weight is desirable.
In other words, the number-average molecular weight _{M b} of the acrylic polymer block (b) is preferably 3,000 or more, more preferably 5,000 or more, more preferably 10,000 or more, particularly preferably 20,000 or more, most preferably 40,000 or more. However, since the polymerization time tends to be longer when the number average molecular weight is large, it may be set according to the required productivity, but is preferably 300,000 or less, more preferably 200000 or less.

Furthermore, the glass transition temperature (Tg _b ) of the acrylic polymer block (b) is preferably 50 ° C. or lower, more preferably 0 ° C. or lower. If Tg _b is higher than 50 ° C., the rubber elasticity of the block copolymer (A) may decrease.
The setting of the glass transition temperature of the acrylic polymer block _(b) (Tg b), as in the case of Tg _a, and those calculated according to the Fox equation.

<Acid anhydride group (c)>
Of the methacrylic polymer block (a) and acrylic polymer block (b), at least one polymer block main chain has an acid anhydride group (c) and / or a carboxyl group (d). It is preferable from the viewpoints of heat resistance, mechanical properties, rubber elasticity improvement, and low hardness of the obtained thermoplastic elastomer composition.

The acid anhydride group (c) has the general formula (1):

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and may be the same or different from each other. N is an integer of 0 to 3, and m is an integer of 0 or 1.) Is done.

N in the general formula (1) is an integer of 0 to 3, preferably 0 or 1, and more preferably 1. When n is 4 or more, polymerization tends to be complicated, and cyclization of the acid anhydride group tends to be difficult.
M in the general formula (1) is an integer of 0 or 1, and when n is 0, m is also 0, and when n is 1 to 3, m is preferably 1.

Since the monomer having an acid anhydride group (c) has a high glass transition temperature (Tg), it has an effect of improving the heat resistance of the block copolymer (A) when introduced into the hard segment. . The glass transition temperature of the polymer having an acid anhydride group (c) is, for example, as high as 159 ° C. for polymethacrylic anhydride, and the heat resistance of the block copolymer (A) can be obtained by introducing the units constituting them. Can be improved.

The acid anhydride group (c) can also be used as a compatibility improving site with the (meth) acrylic polymer (B). Since the acid anhydride group (c) has reactivity with a compound having an amino group, a hydroxyl group or the like, the polymer can be modified to improve compatibility, and to the extent that the thermoplasticity is not impaired (meta It is also possible to improve the compatibility by reacting with the acrylic polymer (B).

The method for introducing the acid anhydride group (c) is not particularly limited, but it is preferable that the acid anhydride group (c) is introduced into the block copolymer (A) in the form of a precursor of the acid anhydride group and then cyclized. For example, the general formula (2):

(In the formula, R ² represents a hydrogen atom or a methyl group. R ³ represents a hydrogen atom, a methyl group or a phenyl group, and a plurality of R ^{3 s} are the same as or different from each other except that at least one methyl group is contained. It is preferable that the block copolymer (A) having at least one unit represented by the following formula is melt-kneaded and cyclized and introduced.

The introduction of the unit represented by the general formula (2) into the block copolymer (A) is performed by copolymerizing an acrylate monomer or a methacrylic acid ester monomer derived from the general formula (2). Can be done by.

Examples of the monomer include t-butyl (meth) acrylate, isopropyl (meth) acrylate, α, α-dimethylbenzyl (meth) acrylate, α-methylbenzyl (meth) acrylate, and the like. It is not limited to. Among these, t-butyl (meth) acrylate is preferable from the viewpoints of availability, ease of polymerization, ease of acid anhydride group formation, and the like.

The unit represented by the general formula (2) is eliminated and cyclized with an adjacent ester unit at a high temperature to form an acid anhydride group (for example, Hatada et al., JMS-PURE). APPL.CHEM., A30 (9 & 10), PP.645-667 (1993)). According to these, generally, an ester unit is bulky, and a polymer having β-hydrogen is decomposed at a high temperature, followed by cyclization to produce an acid anhydride group. By using these methods, an acid anhydride group can be easily introduced into the block copolymer (A).

The formation of the acid anhydride group (c) is preferably performed by heating the block copolymer (A) having an acid anhydride group precursor at a high temperature, and preferably at 180 to 300 ° C. When the temperature is lower than 180 ° C., there is a tendency that the acid anhydride groups are not sufficiently generated, and when the temperature is higher than 300 ° C., the block copolymer (A) itself having a precursor of the acid anhydride group tends to be decomposed.

As a method of heating the block copolymer (A) having an acid anhydride group precursor at a high temperature, the block copolymer (A) having a precursor is heated under pressure in the state of a polymer solution. It may be heated while evaporating and removing the solvent from the polymer solution, or the block copolymer (A) having the precursor may be directly heated and melted, but the reactivity to the acid anhydride group is good. In view of ease of production and the like, the block copolymer (A) having a precursor is preferably directly melted by heating, and more preferably melt-kneaded.

<Carboxyl group (d)>
The carboxyl group (d) has a strong cohesive force, and the monomer having a carboxyl group has a high glass transition temperature (Tg) and has an effect of improving the heat resistance of the block copolymer (A). A functional group such as a hydroxyl group also has a hydrogen bonding ability, but has a lower Tg than that of the monomer having the above functional group, and the effect of improving heat resistance is small. For example, polymethacrylic acid is as high as 228 ° C., and the heat resistance of the block copolymer (A) can be improved by introducing monomers constituting these. Therefore, a carboxyl group (d) may be introduced as necessary from the viewpoint of further improving the heat resistance and cohesive strength of the block copolymer (A).

The method for introducing the carboxyl group (d) is a block copolymer (A) in a form in which the carboxyl group (d) is protected with an appropriate protecting group, or in the form of a functional group that is a precursor of the carboxyl group (d). And then a functional group can be generated by a known chemical reaction.
For example, as disclosed in JP-A-2001-234147 and JP-A-10-298248, carboxyl groups such as t-butyl methacrylate, t-butyl acrylate, trimethylsilyl methacrylate, trimethylsilyl acrylate, etc. There is a method of synthesizing a block copolymer (A) containing a monomer having a functional group to be a precursor of the above, and generating a carboxyl group (d) by a known chemical reaction such as hydrolysis or acid decomposition. As another method, the acid anhydride group (c) can be formed in the process of introducing the acid anhydride group (c) into the block copolymer (A) or by hydrolysis of the acid anhydride group (c).
The method for introducing the carboxyl group (d) is not particularly limited, but when a monomer having a carboxyl group is introduced by direct polymerization under polymerization conditions, the monomer having a carboxyl group can be used as a catalyst during polymerization. The process of introducing the acid anhydride group (c) into the block copolymer (A) because it may be deactivated, has a problem in terms of cost, or tends to be complicated to manufacture. In addition, it is preferable that the acid anhydride group (c) be generated by hydrolysis because the introduction amount of the carboxyl group (d) is easily controlled or introduced.

Examples of the method for generating the carboxyl group (d) in the process of introducing the acid anhydride group (c) into the block copolymer (A) include the methods described below.
In the block copolymer (A) having a unit represented by the general formula (2), the unit represented by the general formula (2) is eliminated and cyclized with an adjacent ester unit at a high temperature to form an acid anhydride group ( c) is generated. At this time, the ester unit is decomposed to generate a carboxyl group (d), and subsequently, cyclization occurs to partially have a route for generating an acid anhydride group. Utilizing this, the carboxyl group (d) can be introduced by appropriately adjusting the heating temperature and time according to the type and content of the unit represented by the general formula (2). In this method, since the carboxyl group (d) tends to cyclize with an adjacent ester unit at a high temperature, when introducing a high content of the carboxyl group (d), the acid anhydride group (c) is added. A method of introducing by hydrolysis is preferred. When the carboxyl group (d) is generated in the process of introduction into the acid anhydride group (c) into the block copolymer (A), the acid anhydride is introduced in the same manner as in the method for introducing the acid anhydride group (c). The block copolymer (A) having the above precursor may be heated under pressure in the state of a polymer solution, and the block copolymer (A) having the acid anhydride group precursor may be directly heated and melted. May be. It is more preferable to melt-knead the block copolymer (A) having an acid anhydride group precursor in terms of ease of production and the like.

Further, when the carboxyl group (d) is preferably formed by hydrolyzing the acid anhydride group (c) and opening the ring, the hydrolysis method is not particularly limited, and the block copolymer having an acid anhydride group is not limited. The polymer (A) may be heated with water under pressure, or the block copolymer (A) having an acid anhydride group may be melt-kneaded with water. It is preferable to melt-knead the block copolymer (A) having an acid anhydride group together with water for ease of production.

The content of the monomer having an acid anhydride group (c) and a carboxyl group (d) depends on the cohesive force, reactivity, block copolymer (A) of the acid anhydride group (c) and the carboxyl group (d). ) Structure and composition, the number of blocks constituting the block copolymer (A), the glass transition temperature, and the site and manner in which the acid anhydride group (c) and carboxyl group (d) are contained. Therefore, it may be set as necessary, and can be introduced into the block copolymer (A) in the range of 0.1 to 99.9% by weight. Is preferably 0.1% by weight or more, and more preferably 0.5% by weight or more. When the content is less than 0.1% by weight, the improvement effect tends to be insufficient when the heat resistance of the block copolymer (A) is improved or the compatibility is improved.

The acid anhydride group (c) and the carboxyl group (d) may be introduced into the methacrylic polymer block (a) or into the acrylic polymer block (b), respectively. Although it may be introduced into the block, in order to improve the heat resistance of the block copolymer (A), it is preferably introduced into the methacrylic polymer block (a), and the (meth) acrylic polymer (B In the case of improving the compatibility with the acrylic polymer block (b), it is preferable to improve the compatibility.

When introduced into the methacrylic polymer block (a), the content of the monomer having an acid anhydride group (c) and a carboxyl group (d) is 0.1 of the methacrylic polymer block (a). It is preferably ˜99.9% by weight, and more preferably 0.5 to 99.9% by weight. If it is less than 0.1% by weight, the effect of improving heat resistance tends to be insufficient. The heat resistance improves as the introduction amount of the acid anhydride group (c) and the carboxyl group (d) increases, but may be appropriately set depending on the cost and the physical properties of the obtained thermoplastic elastomer.

When introduced into the acrylic polymer block (b), the content of the monomer having an acid anhydride group (c) and a carboxyl group (d) is 0.1 to 60 of the acrylic polymer block (b). % By weight is preferable, and 0.5 to 50% by weight is more preferable. When the amount is less than 0.1% by weight, the effect of improving the compatibility with the (meth) acrylic polymer (B) tends to be insufficient. When the amount is more than 60% by weight, the glass transition temperature of the block (b) itself is low. It becomes high and there exists a tendency for the softness | flexibility and rubber elasticity of a block copolymer (A) to fall.

<< (Meth) acrylic polymer (B) >>
As the (meth) acrylic polymer (B) in the present invention, (1) an ab diblock copolymer containing a methacrylic polymer block (a) and an acrylic polymer block (b), ( 2) A (meth) acrylic polymer (b ′) which is not a block copolymer is exemplified, and all are obtained by controlled polymerization.
The (meth) acrylic polymer (B) is a component that contributes to reducing the hardness of the thermoplastic elastomer composition.

(1) When the (meth) acrylic polymer (B) is an ab diblock copolymer containing a methacrylic polymer block (a) and an acrylic polymer block (b) Examples of the methacrylic polymer block (a) and the acrylic polymer block (b) are the same as those described for the block copolymer (A).

In this case, the composition ratio of the methacrylic polymer block (a) and the acrylic polymer block (b) is not particularly limited, but the total amount of (a) and (b) is determined from the viewpoint of reducing hardness. When the content is 100% by weight, the methacrylic polymer block (a) is preferably 5 to 50% by weight, and the acrylic polymer block (b) is preferably 95 to 50% by weight. More preferably, the methacrylic polymer block (a) is 10 to 40% by weight and the acrylic polymer block (b) is 90 to 60% by weight.

(2) When the (meth) acrylic polymer (B) is a (meth) acrylic polymer (b ′) that is not a block copolymer, a (meth) acrylic polymer that is not a block copolymer in this case Although it does not specifically limit as a monomer which comprises the principal chain of (b '), Specifically, (meth) acrylic acid, (meth) acrylic acid methyl, (meth) acrylic acid ethyl, (meth) acrylic acid n- Propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n- (meth) acrylate Hexyl, cyclohexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylate nonyl, (meth) acrylic acid decyl, (meth) acrylic acid dodecyl, (meth) acrylic acid phenyl, (meth) acrylic acid tolyl, (meth) acrylic acid benzyl, (meth) acrylic acid 2-methoxyethyl , 3-methoxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, stearyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylic acid 2-aminoethyl, γ- (methacryloyloxypropyl) trimethoxysilane, ethylene oxide adduct of (meth) acrylic acid, trifluoromethylmethyl (meth) acrylate, 2-trifluoromethylethyl (meth) acrylate, ( (Meth) acrylic acid 2-perfluoroethylethyl, (meth) a 2-perfluoroethyl-2-perfluorobutylethyl acrylate, 2-perfluoroethyl (meth) acrylate, perfluoromethyl (meth) acrylate, diperfluoromethylmethyl (meth) acrylate, (meth) acrylic 2-perfluoromethyl-2-perfluoroethylmethyl acid, 2-perfluorohexylethyl (meth) acrylate, 2-perfluorodecylethyl (meth) acrylate, 2-perfluorohexadecylethyl (meth) acrylate (Meth) acrylic monomers such as
At least one of these can be used.

In addition to the (meth) acrylic monomer, other monomers copolymerizable with the (meth) acrylic monomer can be used.
Examples of the other copolymerizable monomers include aromatic vinyl monomers such as styrene, vinyl toluene, α-methyl styrene, chlorostyrene, styrene sulfonic acid and salts thereof; perfluoroethylene, perfluoropropylene, fluorination Fluorine-containing vinyl monomers such as vinylidene; silicon-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; maleic anhydride, maleic acid, monoalkyl esters and dialkyl esters of maleic acid; monomers of fumaric acid and fumaric acid Alkyl esters and dialkyl esters; maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenyl Maleimide monomers such as maleimide and cyclohexylmaleimide; Acrylonitrile monomers such as acrylonitrile and methacrylonitrile; Amido group-containing vinyl monomers such as acrylamide and methacrylamide; Vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, cinnamon Examples thereof include vinyl esters such as vinyl acid; alkenes such as ethylene and propylene; conjugated dienes such as butadiene and isoprene; vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol.
At least one of these can be used.

The (meth) acrylic polymer (b ′) is preferably mainly composed of the (meth) acrylic monomer. Here, “mainly” means 50 mol% or more of the entire (meth) acrylic polymer (b ′), more preferably 70 mol% or more. If the monomer is less than 50 mol%, the mechanical properties of the resulting thermoplastic elastomer tend to deteriorate, and the oil resistance, heat resistance, flexibility and rubber elasticity tend to be insufficient.

Among the above (meth) acrylic monomers, acrylates are compatible with the block copolymer (A) to be combined and the hardness, oil resistance, heat resistance, flexibility, and rubber elasticity of the resulting thermoplastic elastomer. More preferably, it is a system monomer.

As the acrylic ester monomer, from the viewpoint of the cost and availability of the monomer, the hardness of the resulting thermoplastic elastomer, oil resistance, heat resistance, flexibility, rubber elasticity, ethyl acrylate, n-butyl acrylate, It is preferably at least one monomer selected from the group consisting of 2-methoxyethyl acrylate and 2-ethylhexyl acrylate.
Among the acrylic ester monomers, n-butyl acrylate is preferred from the viewpoint of the low temperature characteristics, cost, and availability of the thermoplastic elastomer composition obtained, and acrylic oil is required when the composition requires oil resistance. Ethyl acid is preferred. In addition, when the obtained thermoplastic elastomer composition requires lower temperature characteristics and flexibility or lower hardness characteristics, 2-ethylhexyl acrylate is preferable, and further, oil resistance and When it is desired to achieve both low temperature characteristics, a mixture of ethyl acrylate, n-butyl acrylate, and 2-methoxyethyl acrylate is preferable.

As described above, as the (meth) acrylic polymer (B), (1) an ab diblock copolymer containing the methacrylic polymer block (a) and the acrylic polymer block (b), (2 ) The (meth) acrylic polymer (b ') which is not a block copolymer has been described. The (meth) acrylic polymer (B) is composed of only (1) or only (2). , (1) and (2) may be used. In addition to the reduction in hardness, it is preferable to use only (1) from the viewpoint of easier handling.
Further, when the (meth) acrylic polymer (B) is composed of both (1) and (2), the ratio of (1) and (2) in the entire (meth) acrylic polymer (B) is There is no particular limitation.

In addition, at least 50% by weight of the monomer constituting the acrylic polymer block (b) contained in the block copolymer (A) and at least 50% by weight of the monomer constituting the (meth) acrylic polymer (B). % Is preferably the same compound.
In this case, the monomers constituting the acrylic polymer block (b) and the (meth) acrylic polymer (B) are ethyl acrylate, n-butyl acrylate, 2-methoxyethyl acrylate and acrylic acid, respectively. It is preferably at least one monomer selected from the group consisting of 2-ethylhexyl.

The molecular weight distribution of the (meth) acrylic polymer (B) of the present invention, that is, the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC). ) Is preferably less than 1.8, more preferably 1.7 or less, even more preferably 1.6 or less, still more preferably 1.5 or less, and particularly preferably 1.4 or less. Yes, most preferably 1.3 or less. When the molecular weight distribution is 1.8 or more, the resulting thermoplastic elastomer composition tends to have high hardness, compression set or mechanical properties.
Further, the number average molecular weight of the (meth) acrylic polymer (B) is preferably 500 to 1,000,000, more preferably 1,000 to 100,000, and still more preferably 5,000 to 50,000.
In addition, in GPC measurement, chloroform is normally used as a mobile phase, a measurement is performed with a polystyrene gel column, and a number average molecular weight etc. can be calculated | required by polystyrene conversion.

<Method for producing block copolymer (A) and (meth) acrylic polymer (B)>
Next, the manufacturing method of a block copolymer (A) and a (meth) acrylic-type polymer (B) is demonstrated.
Although it does not specifically limit as a method to manufacture a block copolymer (A), It is preferable to use control polymerization from the point which is easy to control the molecular weight and structure of a polymer.
Moreover, as a manufacturing method of a (meth) acrylic-type polymer (B), since control of molecular weight is easy, control polymerization is used.

A general radical polymerization method is a simple method. However, in this method, a monomer having a specific functional group is introduced into the polymer only stochastically. However, there is a problem that it is necessary to use a large amount of this monomer, and conversely, a polymer having a low specific functionalization rate can be obtained by using a small amount. Moreover, since it is free radical polymerization, there is also a problem that only a polymer having a wide molecular weight distribution and a high viscosity can be obtained.

Controlled polymerization includes living anionic polymerization, radical polymerization using a chain transfer agent, and living radical polymerization. Of these, living radical polymerization is preferred from the viewpoint of ease of polymerization of the block copolymer (A) and the (meth) acrylic polymer (B) and control of the molecular weight and structure.

Living radical polymerization is radical polymerization in which the activity at the polymerization terminal is maintained without loss. In the narrow sense, living polymerization refers to polymerization in which the terminal always has activity, but generally includes pseudo-living polymerization in which the terminal is inactivated and the terminal is in equilibrium. . The definition here is also the latter. Living radical polymerization has been actively researched by various groups in recent years.

Examples include radicals such as those using a chain transfer agent such as polysulfide, cobalt porphyrin complexes (J. Am. Chem. Soc., 1994, 116, 7943) and nitroxide compounds. Atom transfer radical polymerization (ATRP) using a trapping agent (Macromolecules, 1994, 27, 7228), an organic halide or the like and a transition metal complex as a catalyst. And the like.

As a method for producing the block copolymer (A) and the (meth) acrylic polymer (B) of the present invention, there is no particular limitation as to which method is used, but the ease of control, etc. To atom transfer radical polymerization.

Atom transfer radical polymerization is polymerized using an organic halide or a sulfonyl halide compound as an initiator and a metal complex having a group 7 element, 8 group, 9 group, 10 group or 11 element as a central metal in the periodic table as a catalyst. (For example, Mattyjaszewski et al., Journal of American Chemical Society, J. Am. Chem. Soc., 1995, 117, 5614, Macromolecules, 1995, 28, 7901, Science, 1996, 272, 866, or Sawamoto et al., Macromolecules, 1995, 28, 1721, JP-A-9-208616. No. 1, JP-A-8-4 117 JP).

According to these methods, in general, polymerization proceeds in a living manner and the molecular weight distribution is narrow (Mw / M), although the polymerization rate is very high and radical reaction such as coupling between radicals is likely to occur. Mn = 1.1 to 1.5) polymer is obtained, and the molecular weight can be freely controlled by the charging ratio of the monomer and the initiator.

In the atom transfer radical polymerization method, a monofunctional, difunctional, or polyfunctional compound can be used as the organic halide or sulfonyl halide compound used as an initiator. These may be properly used according to the purpose, and in the case of producing the block copolymer (A), in the case of producing an aba type or babb type triblock copolymer, It is preferable to use a bifunctional compound from the viewpoint of shortening the number of steps and time. When producing a branched block copolymer, a polyfunctional compound should be used from the viewpoint of shortening the number of reaction steps and time. Is preferred. In the case of producing the (meth) acrylic polymer (B), there is no particular limitation. However, in the case of producing an ab type diblock copolymer, an initiator must be obtained. From the standpoint of ease, monofunctional compounds are preferred.

Moreover, it is also possible to use a polymer initiator as the initiator. The polymer initiator is a compound composed of a polymer in which a halogen atom is bonded to the end of a molecular chain among organic halides or sulfonyl halide compounds. Since such a polymer initiator can be produced by a controlled polymerization method other than the living radical polymerization method, a block copolymer obtained by combining polymers obtained by different polymerization methods is obtained. .

Examples of monofunctional compounds include:
C ₆ H ₅ -CH ₂ X,
_{C 6 H 5 -C (H)} (X) -CH 3,
_{C 6 H 5 -C (X)} (CH 3) 2,
R ⁴ —C (H) (X) —COOR ⁵ ,
R ⁴ —C (CH ₃ ) (X) —COOR ⁵ ,
R ⁴ —C (H) (X) —CO—R ⁵ ,
R ⁴ —C (CH ₃ ) (X) —CO—R ⁵ ,
R ⁴ —C ₆ H ₄ —SO ₂ X
And the like.

In the formula, C ₆ H ₅ represents a phenyl group, and C ₆ H ₄ represents a phenylene group (which may be ortho-substituted, meta-substituted, or para-substituted). R ⁴ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. R ⁵ represents a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. X represents chlorine, bromine or iodine.

Specific examples of the alkyl group having 1 to 20 carbon atoms (including alicyclic hydrocarbon group) represented by R ⁴ include, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl. Group, t-butyl group, n-pentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group, isobornyl group and the like. It is done. Specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, and a naphthyl group. Specific examples of the aralkyl group having 7 to 20 carbon atoms include a benzyl group and a phenethyl group.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ⁵ include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. . Specific examples of the alkyl group having 1 to 20 carbon atoms, the aryl group having 6 to 20 carbon atoms, and the aralkyl group having 7 to 20 carbon atoms are the same as those described for R ⁴ above.

Specific examples of the monofunctional compound include, for example, tosyl bromide, methyl 2-bromide propionate, ethyl 2-bromide propionate, butyl 2-bromide propionate, methyl 2-isobutyrate bromide, 2- Examples thereof include ethyl bromide isobutyrate, 2-butyl isobutyrate bromide and the like. Of these, ethyl 2-bromide propionate and butyl 2-bromide propionate are preferred because they are similar to the structure of the acrylate monomer and are easy to control polymerization.

As a bifunctional compound, for example,
_{X-CH 2 -C 6 H 4} -CH 2 -X,
_{X-CH (CH 3) -C} 6 H 4 -CH (CH 3) -X,
_{X-C (CH 3) 2} -C 6 H 4 -C (CH 3) 2 -X,
^{_{X-CH (COOR 6) -}} (CH 2) n -CH (COOR 6) -X,
^{_{X-C (CH 3) (}} COOR 6) - (CH 2) n -C (CH 3) (COOR 6) -X
^{_{X-CH (COR 6) -}} (CH 2) n -CH (COR 6) -X,
^{_{X-C (CH 3) (}} COR 6) - (CH 2) n -C (CH 3) (COR 6) -X,
_{X-CH 2 -CO-CH 2} -X,
X—CH (CH ₃ ) —CO—CH (CH ₃ ) —X,
_{X-C (CH 3) 2} -CO-C (CH 3) 2 -X,
_{X-CH (C 6 H 5} ) -CO-CH (C 6 H 5) -X,
_{X-CH 2 -COO- (CH 2} ) n -OCO-CH 2 -X,
_{X-CH (CH 3) -COO-} (CH 2) n -OCO-CH (CH 3) -X,
_{X-C (CH 3) 2} -COO- (CH 2) n -OCO-C (CH 3) 2 -X,
_{X-CH 2 -CO-CO-} CH 2 -X,
_{X-CH (CH 3) -CO} -CO-CH (CH 3) -X,
_{X-C (CH 3) 2} -CO-CO-C (CH 3) 2 -X,
_{X-CH 2 -COO-C 6} H 4 -OCO-CH 2 -X,
_{X-CH (CH 3) -COO} -C 6 H 4 -OCO-CH (CH 3) -X,
_{X-C (CH 3) 2} -COO-C 6 H 4 -OCO-C (CH 3) 2 -X,
_{X-SO 2 -C 6 H 4} -SO 2 -X
And the like.

Wherein, ^{R 6} represents an alkyl group having 1 to 20 carbon atoms, the number 6 to 20 aryl group carbon, or represents 7-20 aralkyl group carbon. n represents an integer of 0 to 20. C ₆ H ₅ , C ₆ H ₄ and X are the same as described above.

Specific examples of the alkyl group having 1 to 20 carbon atoms, the aryl group having 6 to 20 carbon atoms, and the aralkyl group having 7 to 20 carbon atoms for R ⁶ include the alkyl group having 1 to 20 carbon atoms for R ⁴ , and 6 to 6 carbon atoms. The same as the specific examples of the 20 aryl group and the aralkyl group having 7 to 20 carbon atoms.

Specific examples of the bifunctional compound include, for example, bis (bromomethyl) benzene, bis (1-bromoethyl) benzene, bis (1-bromoisopropyl) benzene, dimethyl 2,3-dibromosuccinate, and 2,3-dibromosuccinate. Diethyl acetate, dibutyl 2,3-dibromosuccinate, dimethyl 2,4-dibromoglutarate, diethyl 2,4-dibromoglutarate, dibutyl 2,4-dibromoglutarate, dimethyl 2,5-dibromoadipate, 2, Diethyl 5-dibromoadipate, Dibutyl 2,5-dibromoadipate, Dimethyl 2,6-dibromopimelate, Diethyl 2,6-dibromopimelate, Dibutyl 2,6-dibromopimelate, Dimethyl 2,7-dibromosuberate , 7-dibromosuberic acid diethyl, 2,7-dibromosuberine Dibutyl, and the like. Among these, bis (bromomethyl) benzene, diethyl 2,5-dibromoadipate, and diethyl 2,6-dibromopimelate are preferable from the viewpoint of availability of raw materials.

As the multifunctional compound, for example,
_{C 6 H 3 - (CH 2} -X) 3,
_{C 6 H 3 - (CH (} CH 3) -X) 3,
_{C 6 H 3 - (C (} CH 3) 2 -X) 3,
_{C 6 H 3 - (OCO-} CH 2 -X) 3,
_{C 6 H 3 - (OCO-} CH (CH 3) -X) 3,
_{C 6 H 3 - (OCO-} C (CH 3) 2 -X) 3,
_{C 6 H 3 - (SO 2} -X) 3
And the like.
In the formula, C ₆ H ₃ represents a trivalent phenyl group (the position of the three bonds may be any one of the positions 1 to 6), and X is the same as described above.

Specific examples of the polyfunctional compound include tris (bromomethyl) benzene, tris (1-bromoethyl) benzene, tris (1-bromoisopropyl) benzene, and the like. Of these, tris (bromomethyl) benzene is preferable from the viewpoint of availability of raw materials.

In addition, when an organic halide or sulfonyl halide compound having a functional group is used in addition to the group for initiating polymerization, a polymer in which a functional group other than the group for initiating polymerization is easily introduced at the terminal or in the molecule is obtained. It is done. Examples of functional groups other than the group that initiates polymerization include alkenyl groups, hydroxyl groups, epoxy groups, amino groups, amide groups, and crosslinkable silyl groups.

Specific examples of the organic halide or halogenated sulfonyl compound having the functional group include those described in JP-A-2003-82192.

In the organic halide or sulfonyl halide compound that can be used as the initiator, the carbon to which the halogen atom is bonded is bonded to the carbonyl group or the phenyl group, and the carbon-halogen bond is activated to perform polymerization. Start.

The amount of the initiator may be determined from the molar ratio with the monomer according to the molecular weight of the required block copolymer (A) and (meth) acrylic polymer (B). That is, the molecular weight of the block copolymer (A) and the (meth) acrylic polymer (B) can be controlled by the number of monomers used per molecule of the initiator.

As the transition metal complex used as the catalyst for the atom transfer radical polymerization, the stability of the transition metal complex and the control of the atom transfer radical polymerization can be easily controlled. A transition metal complex having a group or group 11 element as a central metal is preferred. Among them, monovalent and zerovalent copper, divalent ruthenium, divalent iron, and divalent nickel complexes are preferable because the control of atom transfer radical polymerization is easier. And a copper complex is preferable from the viewpoint of reaction control.

Specific examples of the catalyst include those described in JP-A-2003-82192.

For example, in the polymerization of acrylic monomers such as acrylic acid esters, it is preferable from the viewpoint of polymerization control that the growth terminal of the polymer chain has a carbon-bromine bond, so that the initiator used is an organic bromide or It is a sulfonyl bromide compound, the solvent is preferably acetonitrile, copper bromide, preferably a metal complex catalyst centered on copper contained in cuprous bromide, and a ligand such as pentamethyldiethylenetriamine Is preferably used.

For polymerization of methacrylic monomers such as methacrylic acid esters, it is preferable from the viewpoint of polymerization control that the growth terminal of the polymer chain has a carbon-chlorine bond. It is a chloride or sulfonyl chloride compound, the solvent is preferably a mixed solvent with acetonitrile, and if necessary toluene, etc., and a metal complex catalyst having copper as the central metal, preferably copper contained in cuprous chloride It is preferable to use a ligand such as pentamethyldiethylenetriamine.

The amount of catalyst and ligand to be used may be determined from the relationship between the amount of initiator, monomer and solvent to be used and the required reaction rate. For example, when trying to obtain a polymer with a high molecular weight, the initiator / monomer ratio must be smaller than when trying to obtain a polymer with a low molecular weight. Further, the reaction rate can be increased by increasing the number of catalysts and ligands. In addition, when a polymer having a glass transition point higher than room temperature is produced, the reaction rate tends to decrease when an appropriate organic solvent is added to lower the viscosity of the system and increase the stirring efficiency. In such a case, the reaction rate can be increased by increasing the number of catalysts and ligands.

The atom transfer radical polymerization can be performed in the absence of a solvent (bulk polymerization) or in various solvents. In addition, in bulk polymerization and polymerization performed in various solvents, the polymerization can be stopped midway.

Examples of the solvent that can be used include hydrocarbon solvents, ether solvents, halogenated hydrocarbon solvents, ketone solvents, alcohol solvents, nitrile solvents, ester solvents, carbonate solvents, and the like.
Specific examples of the solvent include those described in JP-A-2003-82192, and at least one kind can be used.

When a solvent is used, the amount used may be appropriately determined from the relationship between the viscosity of the entire system and the required stirring efficiency (ie, reaction rate). In addition, even in the case of bulk polymerization, in the case of terminating polymerization in the middle of various solvents, the monomer conversion rate at the point of stopping the reaction is determined by the viscosity of the entire system and the required stirring efficiency (that is, , Reaction rate).

The polymerization can be carried out in the range of room temperature to 200 ° C, preferably in the range of 50 to 150 ° C.

The atom transfer radical polymerization of the present invention includes so-called reverse atom transfer radical polymerization. Reverse atom transfer radical polymerization is a high oxidation state when a normal atom transfer radical polymerization catalyst generates radicals, for example, peroxidation with respect to Cu (II ′) when Cu (I) is used as a catalyst. This is a method in which a general radical initiator such as a compound is allowed to act, and as a result, an equilibrium state similar to that of atom transfer radical polymerization is produced (Macromolecules 1999, 32, 2872).

In order to produce the block copolymer (A) by the polymerization, a method of sequentially adding monomers; a method of polymerizing the next block using a polymer synthesized in advance as a polymer initiator; Examples include a method of binding the coalescence by reaction.
Any of these methods may be used depending on the purpose, but from the viewpoint of simplicity of the production process, a method by sequential addition of monomers is preferable, and the monomer of the previous block remains. When it is desired to avoid copolymerization in the next block, a method of polymerizing the next block using a polymer synthesized in advance as a polymer initiator is preferable.

Hereinafter, each of the above methods will be described in detail, but the production method of the block copolymer (A) of the present invention is not limited thereto.

In the case of sequential addition of monomers, it is desirable to charge the monomer to be polymerized next when the conversion rate of the monomer charged to be polymerized is 80 to 95%. When the polymerization is allowed to proceed until the conversion rate exceeds 95%, the growth reaction of the polymer chain can be suppressed stochastically. In addition, since the polymer radicals easily react with each other, side reactions such as disproportionation, coupling, and chain transfer tend to occur. If the monomer to be polymerized next is charged when the conversion rate is less than 80%, the monomer charged for the previous polymerization is mixed with the monomer to be polymerized next and co-polymerized. Polymerization may be a problem.
As the order of addition of the monomers, a method in which an acrylic monomer is first charged and polymerized and then a (meth) acrylic monomer is charged and polymerized is preferable from the viewpoint of polymerization control. This is because it is preferable to grow the methacrylic polymer block from the end of the acrylic polymer block.

As a method for polymerizing the next block using a polymer synthesized in advance as a polymer initiator, for example, when the degree of polymerization of the first block is desired, the temperature is once lowered in the living state to stop the polymerization. There is a method in which the monomer of the first block is distilled off under reduced pressure and the like, and then the monomer of the second block is added. When the third and subsequent blocks are to be polymerized, the same operation as that for the second block may be performed. In this method, at the time of polymerization of the second and subsequent blocks, it is possible to avoid copolymerization of the remaining monomers of the previous block.
In this case, as a block polymerization sequence, a method in which an acrylic block is first polymerized and then a (meth) acrylic block is polymerized is preferable from the viewpoint of polymerization control. This is because it is preferable to grow the methacrylic polymer block from the end of the acrylic polymer block.

Here, how to determine the conversion rate of acrylic monomers, methacrylic monomers, etc. will be described. In order to obtain the conversion rate, a gas chromatograph (GC) method, a gravimetric method, or the like can be applied.
In the GC method, the polymerization reaction liquid is sampled as needed before and during the reaction, and GC measurement is performed. From the abundance ratio of the monomer and the internal standard substance previously added to the polymerization system, This is a method for obtaining the consumption rate. The advantage of this method is that each conversion rate can be determined independently even when a plurality of monomers are present in the system.
The weight method is a method in which a polymerization reaction solution is sampled, the solid content concentration is obtained from the weight before drying and the weight after drying, and the conversion rate of the whole monomer is obtained. The advantage of this method is that the conversion can be easily determined.
Among these methods, when a plurality of monomers are present in the system, for example, when an acrylic monomer is included as a copolymerization component of a methacrylic monomer, the GC method is used. preferable.

The reaction liquid obtained by the polymerization contains a mixture of a polymer and a metal complex, and an organic acid containing a carboxyl group or a sulfonyl group is added to form a metal complex and a metal salt. The solid content is removed by filtration, etc., and subsequently impurities such as acids remaining in the solution by adsorption treatment of basic activated alumina, basic adsorbent, solid inorganic acid, anion exchange resin, cellulose anion exchanger. The block copolymer (A) solution can be obtained by removing.

In the polymer solution thus obtained, the polymerization solvent and unreacted monomer are subsequently removed by an evaporation operation, and the block copolymer (A) is isolated. As the evaporation method, a thin film evaporation method, a flash evaporation method, a horizontal evaporation method provided with an extrusion screw, or the like can be used. Since the block copolymer (A) has adhesiveness, efficient evaporation is possible by combining the horizontal evaporation method with an extrusion screw alone or another evaporation method among the above evaporation methods.
The (meth) acrylic polymer (B) can also be produced in the same manner as described above.

<< Thermoplastic elastomer composition >>
The thermoplastic elastomer composition of the present invention contains the block copolymer (A) and the (meth) acrylic polymer (B) in a weight ratio of (A) :( B) = 95: 5 to 50:50. To do.
When the content of the block copolymer (A) is more than 95% by weight, it is difficult to reduce the hardness of the elastomer composition, and when it is less than 50% by weight, the heat resistance of the elastomer composition is lowered.
Moreover, it is preferable to contain by the weight ratio of (A) :( B) = 90: 10-60: 40, and it is more preferable to contain by the weight ratio of 85: 15-65: 35.

If necessary, a thermoplastic resin may be added to the thermoplastic elastomer composition of the present invention. By adding this thermoplastic resin, the mechanical strength of the thermoplastic elastomer composition can be further improved.

Examples of the thermoplastic resin include polyvinyl chloride resin, polyethylene resin, polypropylene resin, cyclic olefin copolymer resin, polymethyl methacrylate resin, polystyrene resin, polyphenylene ether resin, polycarbonate resin, and polyester resin. , Polyamide resins, polyacetal resins, polyphenylene sulfide resins, polysulfone resins, polyimide resins, polyetherimide resins, polyetherketone resins, polyetheretherketone resins, and polyamideimide resins. At least one of these can be used. However, the thermoplastic resin is not limited to these, and various thermoplastic resins can be used. Styrenic elastomer, olefin elastomer, ester elastomer, vinyl chloride elastomer, urethane elastomer, amide elastomer Etc. can also be used.

The thermoplastic elastomer composition of the present invention has a low hardness, but various flexibility-imparting agents may be added as necessary. By adding a flexibility-imparting agent, the thermoplastic elastomer composition can be further reduced in hardness and elongation can be increased. Moreover, it is more advantageous because a large amount of fillers described later can be mixed.

Various fillers may be used in the thermoplastic elastomer composition of the present invention as necessary. The filler is not particularly limited, but wood powder, pulp, cotton chips, asbestos, mica, walnut shell powder, rice husk powder, graphite, white clay, silica (fumed silica, precipitated silica, crystalline silica, fused silica) , Dolomite, anhydrous silicic acid, hydrous silicic acid, etc.), reinforcing fillers such as carbon black; heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic Filling materials such as bentonite, ferric oxide, bengara, aluminum fine powder, flint powder, zinc oxide, activated zinc white, zinc dust, zinc carbonate and shirasu balloon; asbestos, glass fiber, glass filament, carbon fiber, Kevlar fiber, Examples thereof include fibrous fillers such as polyethylene fibers.
Of these fillers, precipitated silica, fumed silica, crystalline silica, fused silica, dolomite, carbon black, calcium carbonate, titanium oxide, talc and the like are preferable.

In the case of silica, silica whose surface is previously hydrophobically treated with an organosilicon compound such as organosilane, organosilazane, or diorganopolysiloxane may be used.
Furthermore, calcium carbonate is surface-treated using surface treatment agents such as organic substances such as fatty acids, fatty acid soaps, fatty acid esters, various surfactants, and various coupling agents such as silane coupling agents and titanate coupling agents. You may use what is given.

When the filler is used, the addition amount is 5 to 1000 parts by weight with respect to 100 parts by weight in total of the block copolymer (A) and the (meth) acrylic polymer (B). It is preferable to use in the range of 20 to 500 parts by weight, and more preferable to use in the range of 40 to 300 parts by weight.
When the blending amount is less than 5 parts by weight, the effect of improving the breaking strength, breaking elongation, adhesiveness and weather resistance of the composition may not be sufficient, and when it exceeds 1000 parts by weight, the workability of the composition is lowered. There are things to do. At least one filler can be used.

Since the thermoplastic elastomer composition of the present invention has flexibility and low hardness, various lubricants may be used as needed for improving processability and reducing friction on the resin surface.
Examples of the lubricant include fatty acids such as stearic acid and palmitic acid; fatty acid metal salts such as calcium stearate, zinc stearate, magnesium stearate, potassium palmitate and sodium palmitate; polyethylene wax, polypropylene wax, and montanic acid wax Waxes; low molecular weight polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene; polyorganosiloxanes such as dimethylpolysiloxane; amide-based lubricants such as octadecylamine, alkyl phosphate, fatty acid ester, ethylenebisstearylamide, tetrafluoroethylene Examples thereof include fluororesin powder such as resin, molybdenum disulfide powder, silicone resin powder, silicone rubber powder, and silica. At least one of these can be used. Of these, stearic acid, zinc stearate, and calcium stearate, which are excellent in cost and processability, are preferable.

Various additives other than the above may be added to the thermoplastic elastomer composition of the present invention, if necessary, for the purpose of adjusting various physical properties of the thermoplastic elastomer.
Examples of such additives include stabilizers, flame retardants, pigments, mold release agents, antistatic agents, antibacterial and antifungal agents, foaming agents, and antioxidants.
Specific examples of such additives are described in, for example, JP-B-4-69659, JP-B-7-108928, JP-A-63-254149, JP-A-64-22904, and the like. Yes. These additives may be appropriately selected depending on the required physical properties, the intended use, and the like.

Examples of the stabilizer include compounds such as triphenyl phosphite, hindered phenol, and dibutyltin maleate, but are not limited thereto. At least one of these can be used.
Examples of the flame retardant include, but are not limited to, triphenyl phosphate, tricresyl phosphate, decabromobiphenyl, decabromobiphenyl ether, and antimony trioxide. At least one of these can be used.
Examples of the pigment include, but are not limited to, titanium oxide, zinc sulfide, and zinc oxide. At least one of these can be used.

The method for producing the thermoplastic elastomer composition of the present invention is not particularly limited, and the block copolymer (A), the (meth) acrylic polymer (B), and the various components used as necessary are uniform. Any method that can be mixed can be employed.
For example, various apparatuses capable of performing heating and kneading at the same time can be used, and a closed kneading apparatus such as a reaction vessel equipped with a stirring blade, a lab plast mill, a Brabender, a Banbury mixer, a kneader, a roll, or the like A continuous melt kneader such as a batch kneader, a single screw extruder, or a twin screw extruder can be used.

The kneading temperature for producing the composition is preferably 100 to 300 ° C, more preferably 130 to 250 ° C. When the temperature is lower than 100 ° C., the block copolymer (A) is not sufficiently melted and kneading with the (meth) acrylic polymer (B) tends to be uneven. When the temperature is higher than 300 ° C., the block copolymer (A) and the (meth) acrylic polymer (B) itself tend to be decomposed.

Since the thermoplastic elastomer of the present invention has flexibility and low hardness, various lubricants may be applied to prevent blocking when it is produced in a powder form or a pellet form.
Specific examples of the lubricant include the above-mentioned lubricant, calcium carbonate, talc, kaolin, alumina, aluminum hydroxide, acrylic polymer fine particles, and the like. It is preferably at least one selected from these groups. Calcium carbonate and talc are preferred from the viewpoint of cost. In particular, when the methacrylic polymer block (a) in the block copolymer (A) uses methyl methacrylate as a main component, a polymethyl methacrylate resin Use of powder as a lubricant is preferable because the influence of physical properties of the product due to the addition of the lubricant is hardly considered.

In the present invention, as a method of applying a lubricant to the powder or pellet, the powder or pellet may be produced without the lubricant, and the lubricant may be applied to the obtained powder or pellet. May be.
As a method of producing pellets without a lubricant and applying a lubricant to the obtained pellets, a method of dispersing polymer pellets in a solvent containing a lubricant, a method of spraying a solvent containing a lubricant on a pellet, For example, a method of directly mixing the pellet and the lubricant. Moreover, as a method of apply | coating simultaneously at the time of a pellet manufacturing process, an underwater cut system, a strand cut system, etc. are mentioned, for example. In pellet manufacturing by the underwater cut method, it may be necessary to prevent blocking of pellets in the vicinity of a die and a cutter. In this case, since the polymer is cut in the circulating cooling water, the blocking property can be improved by adding one or more lubricants to the circulating cooling water. In the strand cutting method, the resin discharged from the die is high temperature, and it is common to cut the strand in the aqueous phase, solidify the resin, and then cut the resin. It is also possible to develop an anti-blocking effect on the pellets by adding and dispersing the lubricant and then immersing the strand in the aqueous phase to attach the lubricant to the surface.

The thermoplastic elastomer composition of the present invention can be molded using a molding method and a molding apparatus generally employed for a thermoplastic resin composition, for example, melt molding by extrusion molding, injection molding, press molding, blow molding or the like. it can.

The thermoplastic elastomer composition of the present invention is excellent in mechanical properties, oil resistance, heat resistance, and compression set properties while having low hardness and flexibility, and therefore, packing materials, sealing materials, gaskets, plugs, etc. Sealing materials, CD dampers, architectural dampers, damping materials for automobiles, vehicles, home appliances, vibration damping materials, automotive interior materials, cushioning materials, daily necessities, electrical parts, electronic parts, sports materials, grips Alternatively, it can be effectively used as a buffer material, a wire covering material, a packaging material, a sheet, a film material, a base polymer of an adhesive, a resin modifier, various containers, a stationery part, and the like.

The thermoplastic elastomer composition of the present invention has low hardness, flexibility, and excellent mechanical properties, oil resistance, heat resistance, and compression set properties. Can be suitably used.

EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.
In the examples, BA, EA, MEA, MMA, and TBMA each represent n-butyl acrylate, ethyl acrylate, 2-methoxyethyl acrylate, methyl methacrylate, and t-butyl methacrylate. Moreover, co means random copolymerization and b means block copolymerization.

In addition, measurement of molecular weight, acid anhydride group conversion, and analysis of acid conversion were performed by the following methods.
(Molecular weight)
The molecular weights of the block copolymer (A) and the (meth) acrylic polymer (B) shown in this example were measured using a GPC analyzer (system: Waters) using a polystyrene gel column with chloroform as the mobile phase. GPC system manufactured by KK, column: Shodex K-804 (polystyrene gel) manufactured by Showa Denko KK) was used to determine the molecular weight in terms of polystyrene.

(Acid anhydride group conversion and acid conversion analysis)
The acid anhydride group conversion reaction of the block copolymer was confirmed using an infrared spectrum (manufactured by Shimadzu Corporation, FTIR-8100) and nuclear magnetic resonance (manufactured by BRUKER, AM400).
At the time of nuclear magnetic resonance analysis, the block body of the carboxylic acid ester structure is analyzed using deuterated chloroform as the measurement solvent, and the block body of the acid anhydride type structure and the carboxylic acid type block body are using heavy acetone as the measurement solvent. Analysis was carried out.

Production Example 1: Synthesis of MMA-BA-MMA (BA / MMA = 70/30 wt%) type block copolymer (hereinafter abbreviated as MBAM) After purging the inside of a polymerization vessel of a 5 L separable flask with nitrogen, 11.3 g (78.5 mmol) of copper bromide was weighed, and 180 mL of acetonitrile (dried with molecular sieves and then bubbled with nitrogen) was added. After heating and stirring at 70 ° C. for 5 minutes, the mixture was cooled to room temperature again, and initiator 5.7 g (15.7 mmol) of diethyl 2,5-dibromoadipate and 804.6 g (900.0 mL) of n-butyl acrylate were added. added. The mixture was heated and stirred at 80 ° C., and 1.6 mL (7.9 mmol) of ligand pentamethyldiethylenetriamine (hereinafter also referred to as triamine) was added to initiate polymerization. About every 0.2 mL of the polymerization solution was sampled from the polymerization solution for sampling at regular intervals from the start of polymerization, and the conversion of n-butyl acrylate was determined by gas chromatogram analysis of the sampling solution. The polymerization rate was controlled by adding triamine as needed.
When the conversion of n-butyl acrylate was 95%, methyl methacrylate, 345.7 g (369.3 mL), copper chloride, 7.8 g (78.5 mmol), triamine, 1.6 mL (7.9 mmol) Toluene (dried with molecular sieves and then bubbled with nitrogen) 1107.9 mL was added. Similarly, the conversion rate of methyl methacrylate was determined.
When the conversion rate of methyl methacrylate was 85% and the conversion rate of n-butyl acrylate was 98%, 1500 mL of toluene was added and the reactor was cooled in a water bath to complete the reaction. During the reaction, the polymerization solution was always green.

The reaction solution was diluted with 4000 mL of toluene, 22.1 g of p-toluenesulfonic acid monohydrate was added, and the mixture was stirred at room temperature for 3 hours. After filtering out the precipitated insoluble part with a Kiriyama funnel, 9.7 g of adsorbent Kyoward 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the polymer solution, and the mixture was further stirred at room temperature for 3 hours. The adsorbent was filtered with a Kiriyama funnel to obtain a colorless and transparent polymer solution. This solution was dried to remove the solvent and residual monomer to obtain the target MBAM.
When GPC analysis of the obtained MBAM was performed, the number average molecular weight Mn was 105300, and the molecular weight distribution Mw / Mn was 1.38. The composition analysis by NMR was BA / MMA = 70/30 (wt%).

Production Example 2: Synthesis of an acid anhydride group-containing block copolymer (hereinafter abbreviated as 20AN3A6) 20AN3A6 is a precursor of 20AN3A6 (MMA-co-TBMA) -b- (BA-co-EA-co -MEA) -b- (MMA-co-TBMA) [Note that MMA / TBMA = 80/20 mol%, (BA-co-EA-co-MEA) / (MMA-co-TBMA) = 60/40 wt%] A type block copolymer (hereinafter referred to as 20T3A6) was synthesized and then converted into an acid anhydride group.

A 500 L reactor was charged with 851.5 g (5.84 mol) of cuprous bromide, and the inside of the reactor was purged with nitrogen. A solution prepared by previously mixing 7056 g of acetonitrile and 8046 g of BA was charged in a state where the pressure in the reactor was reduced, and the temperature was raised to 68 ° C. and stirred for 30 minutes. Thereafter, a mixed solution of BA14589g, EA22226.9g, MEA13789.9g and butyl acetate 1111.3g, and a solution prepared by dissolving 427.4g of diethyl 2,5-dibromoadipate in 2826g of acetonitrile were charged, and the temperature was raised to 85 ° C. The mixture was further stirred for 30 minutes. 102.9 g of triamine was added, and copolymerization of BA / EA / MEA to be the first block was started.
When the conversion rate reached 95%, toluene 96202.9 g, cuprous chloride 587.7 g, MMA 30513.5 g, TBMA 10834.2 g were charged, triamine 102.9 g was added, and MMA and TBMA as the second block were added. Copolymerization was started.
When the conversion rate reached 60%, 69280 g of toluene was added to dilute the reaction solution, and the reactor was cooled to stop the polymerization. When the GPC analysis of the obtained block copolymer was conducted, the number average molecular weight Mn was 107400, and molecular weight distribution Mw / Mn was 1.28.
Toluene was added to the resulting block copolymer solution to adjust the polymer concentration to 24% by weight, 847 g of p-toluenesulfonic acid was added, the inside of the reactor was purged with nitrogen, and the mixture was stirred at room temperature for 3 hours. did. The reaction solution was sampled, and the reaction was stopped after confirming that the solution was colorless and transparent. Thereafter, the solution was dispensed, and solid-liquid separation was performed to remove the solid content. 827 g of Kyoward 500SH was added to 50 L of this block copolymer solution, the inside of the reactor was purged with nitrogen, and the mixture was stirred at room temperature for 3 hours. The reaction solution was sampled, and the reaction was stopped after confirming that the solution was neutral. Thereafter, the solution was discharged, and solid-liquid separation was performed to remove the adsorbent.

The polymer solution was supplied to an evaporator equipped with a ventro, and the polymer was isolated by evaporating the solvent and unreacted monomers. The temperature of the trunk jacket and screw of the evaporator was adjusted to 180 ° C., and the inside of the evaporator was kept at a reduced pressure of about 0.01 MPa or less by a vacuum pump. In this way, 20T3A6 pellets were obtained.
When the GPC analysis of the obtained acrylic block copolymer 20T3A6 was performed, the number average molecular weight Mn was 108240, and the molecular weight distribution Mw / Mn was 1.49.

The obtained 20T3A6 pellets were placed in a TEX44 extruder (screw diameter 44 mm, L / D 42.25, manufactured by Nippon Steel Co., Ltd.), all blocks at 240 ° C., screw rotation speed 150 rpm, and discharge rate 20 kg / By setting to hr and performing an extrusion treatment, an acid anhydride group-containing block copolymer (hereinafter 20AN3A6) was obtained.
The conversion of the t-butyl ester moiety to carboxylic anhydride and carboxylic acid could be confirmed by IR (infrared absorption spectrum) and ¹³ C-NMR (nuclear magnetic resonance spectrum). That is, it was confirmed by IR that an absorption spectrum derived from an acid anhydride group was observed around 1800 cm ⁻¹ after conversion. ^{In 13} C ( ¹ H) -NMR, the 82 ppm signal derived from the methine carbon of the t-butyl group and the 28 ppm signal derived from the methyl carbon disappeared after the conversion, and 176 to 179 ppm (newly derived from the carboxyl carbon of the carboxylic acid). It was confirmed from the appearance of the signal of m) and the signal of 172 to 173 ppm (m) derived from the carboxyl carbon of the carboxylic acid anhydride.
The monomer having an acid anhydride group and the monomer having a carboxyl group were 1% by weight and 7% by weight, respectively, in the obtained block copolymer. Each content was determined by ¹³ C ( ¹ H) -NMR analysis.

Production Example 3: Synthesis of BA-MMA (BA / MMA = 80/20 wt%) type block copolymer (hereinafter abbreviated as BAM) The inside of a polymerization vessel of a 500 mL separable flask was purged with nitrogen, and then brominated. 1.13 g (7.85 mmol) of copper was weighed, and 15 mL of acetonitrile (dried with molecular sieves and then bubbled with nitrogen) was added. After stirring with heating at 70 ° C. for 5 minutes, the mixture was cooled again to room temperature, and 0.448 g (2.68 mmol) of methyl 2-bromopropionate and 80.5 g of n-butyl acrylate were added. The mixture was heated and stirred at 80 ° C., and 0.28 mL (1.3 mmol) of ligand triamine was added to initiate polymerization. About every 0.2 mL of the polymerization solution was sampled from the polymerization solution for sampling at regular intervals from the start of polymerization, and the conversion of n-butyl acrylate was determined by gas chromatogram analysis of the sampling solution. The polymerization rate was controlled by adding triamine as needed.
When the conversion rate of n-butyl acrylate was 95%, methyl methacrylate 23.4 g, copper chloride 0.78 g (7.84 mmol), triamine 0.28 mL (1.3 mmol), toluene (nitrogen bubbling) 75 mL) was added. Similarly, the conversion rate of methyl methacrylate was determined.
When the conversion rate of methyl methacrylate was 85% and the conversion rate of n-butyl acrylate was 98%, 450 mL of toluene was added, and the reaction was terminated by cooling the reactor in a water bath. During the reaction, the polymerization solution was always green.

The reaction solution was diluted with 400 mL of toluene, 2.21 g of p-toluenesulfonic acid monohydrate was added, and the mixture was stirred at room temperature for 3 hours. The precipitated insoluble part was removed by filtration with a Kiriyama funnel, 1.0 g of adsorbent Kyoward 500SH was added to the polymer solution, and the mixture was further stirred at room temperature for 3 hours. The adsorbent was filtered with a Kiriyama funnel to obtain a colorless and transparent polymer solution. This solution was dried to remove the solvent and residual monomer to obtain the target BAM.
When GPC analysis of the obtained BAM was performed, the number average molecular weight Mn was 50950, and the molecular weight distribution Mw / Mn was 1.41. The composition analysis by NMR was BA / MMA = 79/21 (% by weight).

Production Example 4: 1.11 kg of copper bromide was charged into a synthetic stirrer and jacketed 250 L reactor having an alkenyl group having an alkenyl group at the terminal and a jacketed 250 L reactor, and the inside of the reaction vessel was purged with nitrogen. . 5.0 kg of acetonitrile was added, warm water was passed through the jacket, and the mixture was stirred at 70 ° C. for 15 minutes. A mixture of BA 6.6 kg, EA 9.5 kg, methoxyethyl acrylate 7.8 kg, diethyl 2,5-dibromoadipate 3.09 kg and acetonitrile 5.0 kg was added, and the mixture was further stirred at 70 ° C. for about 30 minutes. Triamine was added to this to start the reaction. Triamine was appropriately added during the reaction, and polymerization was carried out at an internal temperature of about 70 to 80 ° C. The total amount of triamine used in the polymerization process was 45 g. Four hours after the start of the reaction, unreacted monomer and acetonitrile were devolatilized by heating and stirring at 80 ° C. under reduced pressure. 29.9 kg of acetonitrile, 28.4 kg of 1,7-octadiene and 446 g of triamine were added to the concentrate, and stirring was continued for 6 hours. The mixture was heated and stirred at 80 ° C. under reduced pressure to devolatilize acetonitrile and unreacted 1,7-octadiene, and concentrated. 120 kg of toluene was added to the concentrate to dissolve the polymer. Solid copper in the polymer mixture was filtered through a bag filter (manufactured by HAYWARD, nominal filter cloth pore diameter: 1 μm). In the filtrate, Kyoward 500SH as an adsorbent (manufactured by Kyowa Chemical Industry Co., Ltd .: 2 parts by weight with respect to 100 parts by weight of the copolymer), Kyoward 700SL (manufactured by Kyowa Chemical Industry Co., Ltd .: 100 parts by weight of the copolymer) 2 parts by weight) was added, and the mixture was heated and stirred at 120 ° C. for 2 hours in an oxygen-nitrogen mixed gas atmosphere (oxygen concentration 6%). Insoluble matter in the mixture was filtered off. The filtrate was concentrated to obtain a copolymer. The copolymer was heated and devolatilized at 180 ° C. for 12 hours (decompression degree: 10 torr or less) to desorb Br groups from the copolymer.

To the copolymer, toluene (100 parts by weight with respect to 100 parts by weight of the copolymer), Kyoward 500SH (2 parts by weight with respect to 100 parts by weight of the copolymer), and Kyoward 700SL (to 100 parts by weight of the copolymer) 2 parts by weight), a hindered phenol antioxidant (irganox 1010; manufactured by Ciba Specialty Chemicals Co., Ltd., 0.05 parts by weight), and under an oxygen-nitrogen mixed gas atmosphere (oxygen concentration 6%), The mixture was heated and stirred at 130 ° C. for 4 hours. Insoluble matter in the mixture was filtered off. The filtrate was concentrated to obtain alkenyl group-terminated copolymer 3A.
3A had a number average molecular weight of 18,000 and a molecular weight distribution of 1.1. When the average number of alkenyl groups introduced per molecule of the copolymer was determined by ¹ H-NMR analysis, it was 1.9.

Example 1
Laboplast mill 50C150 (blade shape: set to 190 ° C.) using MBAM produced in Production Example 1 and BAM produced in Production Example 3 and irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd.) in the ratio shown in Table 1. Using a roller type R60, manufactured by Toyo Seiki Co., Ltd., the mixture was melt-kneaded for 10 minutes to obtain a thermoplastic elastomer.
The obtained thermoplastic elastomer was hot-pressed at a set temperature of 190 ° C. (compression molding machine NSF-50, manufactured by Shindo Metal Industry Co., Ltd.) to obtain a cylindrical molded body having a diameter of 30 mm and a thickness of 12 mm. These molded bodies were measured for hardness and compression set. Similarly, hot press molding was performed at a set temperature of 190 ° C. to obtain a sheet-like molded body having a thickness of 2 mm. The mechanical strength was measured on these sheets.

Example 2, Comparative Examples 1-3
Except having changed the used raw material into the component and quantity shown in Table 1, it carried out similarly to Example 1 and obtained the thermoplastic elastomer and its molded object.
In Table 1, Irganox 1010 (manufactured by Ciba Specialty Chemicals) was used as an antioxidant, and epoxidized soybean oil O-130P (manufactured by Asahi Denka Kogyo Co., Ltd.) was used as a plasticizer. Furthermore, the compounding quantity of each component in Table 1 is a weight part.

The thermoplastic elastomers obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were measured for appearance, hardness, mechanical strength, and compression set as follows, and the results are shown in Table 1.

(appearance)
The appearance (transparency) was evaluated by visual observation.
(hardness)
Hardness was measured in accordance with JIS K 6253 using a cylindrical molded body (diameter 30 mm, thickness 12 mm) as a test piece, and hardness at 23 ° C. and relative humidity 50 ± 5% (immediately after using JIS-A; type A durometer). The reading immediately after the contact of the pressing surface was measured.

(Mechanical strength)
The breaking strength (MPa) and the elastic modulus were measured by applying a method described in JIS K 7113, using an autograph AG-10TB type manufactured by Shimadzu Corporation at a test speed of 500 mm / min at 23 ° C. The measurement was performed at n = 3, and an average value of strength (MPa) and elongation (%) when the test piece broke was adopted. Note that the test piece is in the shape of 2 (1/3) and about 2 mm thick. As a general rule, the test piece is tested at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5% for 48 hours. What was adjusted as described above was used.

(Compression set)
The compression set is in accordance with JIS K 6301. A cylindrical molded body (diameter 30 mm, thickness 12 mm) is held at 100 ° C. for 22 hours under the condition of a compression ratio of 25%, and left at room temperature for 30 minutes. The thickness of the molded body was measured at 2 ° C., and the residual strain was calculated. That is, it corresponds to the fact that all the distortion is recovered at a compression set of 0%, and the distortion is not recovered at all at a compression set of 100%.

From Table 1, it was recognized that the thermoplastic elastomer composition of the present invention is a composition that can ensure good heat resistance, which is difficult to achieve with a normal plasticizer, while having low hardness.

The thermoplastic elastomer composition of the present invention has low hardness, flexibility, and excellent mechanical properties, oil resistance, heat resistance, and compression set properties. Can be suitably used.

Claims (7)

A block copolymer (A) containing a methacrylic polymer block (a) and an acrylic polymer block (b), and a block obtained by controlled polymerization of 50 mol% or more of a (meth) acrylic monomer A thermoplastic elastomer composition comprising a (meth) acrylic polymer (B) which is not a copolymer and having a weight ratio of (A) :( B) = 95: 5 to 50:50. The block copolymer (A) has the general formula b- (ab) _r , general formula (ab) _r -a
2. The thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer composition is at least one selected from the group consisting of block copolymers represented by the formula (wherein r is an integer of 1 or more). At least 50% by weight of the monomer constituting the acrylic polymer block (b) contained in the block copolymer (A) and at least 50% by weight of the monomer constituting the (meth) acrylic polymer (B) The thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer composition is the same compound. The monomers constituting the acrylic polymer block (b) and the (meth) acrylic polymer (B) contained in the block copolymer (A) are ethyl acrylate, n-butyl acrylate, 2-acrylic acid 2- The thermoplastic elastomer composition according to any one of claims 1 to 3, which is at least one monomer selected from the group consisting of methoxyethyl and 2-ethylhexyl acrylate. In the main chain of at least one of the methacrylic polymer block (a) and the acrylic polymer block (b) contained in the block copolymer (A), the general formula (1):

(Wherein R ¹ represents a hydrogen atom or a methyl group, and may be the same or different from each other. N represents an integer of 0 to 3, and m represents an integer of 0 or 1). The thermoplastic elastomer composition according to any one of claims 1 to 4, which has a group (c) and / or a carboxyl group (d). The thermoplastic elastomer composition according to any one of claims 1 to 5, wherein the block copolymer (A) is obtained by atom transfer radical polymerization. The thermoplastic elastomer composition according to claim 6, wherein the atom transfer radical polymerization uses a copper complex as a catalyst.