JP2572226B2 - Block copolymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a block copolymer mainly composed of a vinyl aromatic compound and a lactone and having excellent weather resistance, oil resistance and impact resistance.

[PRIOR ART] Examples of block polymers containing a lactone known hitherto include polystyrene-polybutadiene-poly (ε-) obtained by an anionic polymerization method described in JP-B-46-37737. Cabrolactone) block copolymer. This block copolymer contains a crystalline lactone polymer block and has excellent oil resistance, but also contains a conjugated diene polymer block, so that it has poor weather resistance. JP-B-47-27151 reports a block copolymer comprising a vinyl aromatic compound polymer block and a lactone polymer block. However, this block copolymer has a structure in which a lactone polymer block is located at the terminal, which is a main component, and thus has excellent weather resistance in addition to oil resistance, but is inferior in impact resistance.

[Problems to be Solved by the Invention] The present invention aims at improving impact resistance while maintaining the advantages of a block copolymer containing a lactone polymer block having excellent oil resistance and weather resistance. .

[Means for Solving the Problems] The present inventors have studied extensively to improve the impact resistance of a block copolymer containing a lactone polymer block, and as a result, the block copolymer of the present invention has The inventors have found that they are excellent in any of oil resistance, weather resistance and impact resistance, and have completed the present invention.

That is, the present invention provides ring-opening polymerization of a polymer block (hereinafter referred to as A) obtained by polymerizing a monomer mainly containing a vinyl aromatic compound obtained using an organolithium compound as a polymerization initiator and a monomer mainly containing lactone. [Hereinafter referred to as a block copolymer with a polymer block (hereinafter referred to as “B”) (A—O—B (the bonding portion of OB is —O—
The term “CO-bonded” means that the terminal block represented by (A—O—B _n X) contains a block copolymer in which only the A is present. It is a characteristic block copolymer.

 Hereinafter, the present invention will be described in detail.

In the present invention, B is a general formula R ₁ , R ₂ : hydrogen or an alkyl group having 1 to 20 carbon atoms, cycloalkyl group, aryl group, alkenyl group m: 2,4,5,6 X is a polymer block obtained by R ₃ : an aliphatic group having 1 to 20 carbon atoms, a cycloaliphatic group, or an aromatic group l: a binder residue represented by an integer of 2 or more.

n represents an integer of 2 or more and 1 or less.

The B-terminal-bound block copolymer is 50% by weight in the block copolymer of the present invention. It is necessary that it be contained above, and it is preferably not less than 70% by weight, and if it is less than 50% by weight, impact resistance is undesirably lowered.

A and B can change their structures essentially without impairing their physical and chemical properties. For example, conjugated dienes may be arranged almost randomly in the structure of A.

The content of the vinyl aromatic compound in the block copolymer of the present invention is 10 to 90% by weight when the melting point of B exceeds 25 ° C,
When the temperature is 25 ° C. or less, it is higher than 55% by weight and 90% by weight or less. Preferably, it is at most 85% by weight.

If the content of the vinyl aromatic compound is less than 10% by weight, the rigidity is lowered, which is not preferable. If it is more than 90% by weight, the impact resistance is remarkably reduced.

In the present invention, the number average molecular weight (hereinafter referred to as Mn) of AOB is 5,000 to 500,000, preferably 1 to 500,000.
It is between 0,000 and 300,000. If Mn is less than 5,000, impact resistance is remarkably reduced, and if it exceeds 500,000, workability is deteriorated, which is not preferable.

Further, the ratio of the weight average molecular weight (hereinafter referred to as Mw) of AOB to Mn (Mw / Mn) needs to be 3.0 or less. Preferably it is 2.0 or less. If (Mw / Mn) exceeds 3.0, the impact resistance is undesirably reduced. Mn and Mw specified in the present invention are determined by gel permeation chromatography (hereinafter referred to as GPC) in terms of standard polystyrene.

The block copolymer of the present invention is a polymer obtained by polymerizing a first monomer mainly composed of a vinyl aromatic compound using an organolithium compound as a polymerization initiator and having a lithium atom bonded to a polymer chain terminal. The union is reacted with an oxirane compound, aldehyde or ketone to form a polymer chain terminal. Is modified into -O-Li, and then a second monomer mainly composed of lactone is subjected to ring-opening polymerization under specific polymerization conditions to form A-OB
And then binding the B-termini with a specific halogen-containing binder.

As a method for producing a polymer block obtained by polymerizing a first monomer mainly composed of a vinyl aromatic compound having a lithium atom bonded to a polymer chain terminal used in the present invention,
There is a method of polymerizing a vinyl aromatic compound using an organic lithium compound as an anionic polymerization initiator in an inert hydrocarbon solvent.

As the organic lithium compound used in the present invention, for example, an organic monolithium compound, n-butyllithium, sec-
Butyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium and the like. These are used alone or in a mixture of two or more. The amount of the polymerization initiator used is usually 0.2 to 30 m per 100 g of the monomer.
mol.

The inert hydrocarbon solvent used in the present invention includes n
-Aliphatic hydrocarbons such as hexane, butane, pentane, heptane, octane, cyclohexane, cyclopentane,
There are alicyclic hydrocarbons such as methylcyclohexane, and aromatic hydrocarbons such as benzene, toluene, and xylene. Also, α-methylstyrene, which can be a polymerization monomer, can be used as the polymerization solution. These alone,
Alternatively, two or more kinds can be used in a mixture. As a preferable solvent, an aromatic hydrocarbon having excellent solubility in the second monomer mainly composed of lactone is preferable. Particularly preferred solvents include benzene and toluene. Also, a small amount of a polar compound such as ether or tertiary amine may be co-present in an inert solvent for the purpose of accelerating the polymerization initiation reaction.

Examples of the vinyl aromatic compound used in the present invention include styrene, p-methylstyrene, α-methylstyrene,
Although p-tert-butylstyrene etc. are mentioned, styrene and p-methylstyrene are preferable. These may be used alone or in combination of two or more. The preferred polymerization temperature range of the vinyl aromatic compound is from -20 to 120C.

A polymer obtained by polymerizing a first monomer mainly composed of a vinyl aromatic compound having a lithium atom bonded to a polymer chain terminal used in the present invention is reacted with an oxirane compound, an aldehyde or a ketone to form a polymer chain. Terminal May be modified by any known method, for example, JP-B-46-37737 and JP-B-47-377.
-27151 and the like. That is, the polymer terminal By reacting at least one molecule of an oxirane compound having one oxirane group in the molecule, one aldehyde or ketone having one carbonyl group in the molecule,
This is a method of modifying to O-Li. The temperature range of this denaturation reaction is -100 to 150C, preferably -50 to 100C.

Oxirane compounds, aldehydes, and ketones used for modifying the polymer chain terminal in the present invention include epichlorohydrin, ethylene oxide, propylene oxide, β-butylene oxide, 1,2-epoxy-3-methylbutylene, and 1,2. -Epoxycyclohexane, acetaldehyde, benzaldehyde, decanal, eicosanal, 2-phenylbutanal, propanal, acetone, acetophenone, benzophenone, acetylcyclohexane, cyclopentyl ketone, 2-butanone, cyclopentanone, cyclohexanone and the like. Preferred compounds include oxirane compounds, and particularly preferred compounds are ethylene oxide and propylene oxide.

In the block copolymer of the present invention, it is necessary that the range of the polymerization temperature at the time of ring-opening polymerization of the second monomer mainly composed of lactone be -100 to 70 ° C. Preferably 0
In the range of ~ 50 ° C. If the temperature is lower than -100 ° C, the polymerization rate is too slow, which is not preferable. If the temperature is higher than 70 ° C, an undesirable side reaction occurs during lactone polymerization, and the block copolymer of the present invention cannot be obtained. That is, when polymerized at 70 ° C. or more, the value of the ratio (Mw / Mn) of Mw to Mn of the block copolymer AOB becomes 3.0.
Larger polymer is produced, also, undesirably block copolymer B-terminal is bound (the content of A-O-B _n X is a block copolymer of less than 50% by weight of the present invention. Further It is not preferable because a homopolymer composed only of the second monomer mainly composed of lactone is formed, and the amount of the homopolymer mainly composed of lactone is preferably 5% by weight or less in the composition. The polymerization time of the second monomer varies depending on the initiator used, the type and amount of the monomer, and the usual polymerization time ranges from 1 minute to 5 hours.

As the lactone used in the present invention, β-propiolactone, δ-valerolactone, ε-caprolactone, pivalolactone, α-methyl-δ-valerolactone, β-methyl-δ-valerolactone, β-methyl −
There are ε-caprolactone, ε-methyl-ε-caprolactone, and lactones corresponding to the following acids:

2-methyl-3-hydroxy-propionic acid, 2-dodecyl-3-hydroxypropionic acid, 2-cyclopentyl-3-hydroxypropionic acid, 3-phenyl-3
-Hydroxypropionic acid, 2-naphthyl-3-hydroxypropionic acid, 2-n-butyl-3-cyclohexyl-3-hydroxypropionic acid, 2- (2-methylcyclopentyl) -3-hydroxypropionic acid, 2-methylphenyl -3-hydroxypropionic acid, 3-benzyl-3-hydroxypropionic acid, 2,2-dimethyl-
3-hydroxypropionic acid, 3-cyclohexyl-5
-Hydroxyvaleric acid, 4-phenyl-5-hydroxyvaleric acid, 2-heptyl-4-cyclo-pentyl-5-hydroxyvaleric acid-2-methyl-3-phenyl-5-hydroxyvaleric acid, 3 -(2-cyclohexylethyl) -5-hydroxyvaleric acid, 2
-(2-phenylethyl) -4- (4-cyclohexylbenzyl) -5-hydroxyvaleric acid, 3-ethyl-5-isopropyl-6-hydroxycaproic acid, 2-
Cyclopentyl-4-hexyl-6-hydroxycaproic acid, 3-phenyl-6-hydroxycaproic acid, 3-
(3,5-diethylcyclohexyl) -5-ethyl-6-
Hydroxycaproic acid, 4- (3-phenylpropyl)
-6-hydroxycaproic acid, 2-benzyl-5-isobutyl-6-hydroxycaproic acid and the like.

Particularly preferred lactones are β-propiolactone, δ-valerolactone, and ε-caprolactone. These are preferably 80% by weight of one type of lactone
And may contain other lactones or compounds copolymerizable with lactones. The kind and amount of the monomer to be used are adjusted so that the melting point of B exceeds 25 ° C. if it is 55% by weight or less, depending on the content of the vinyl aromatic compound in the copolymer block to be produced.

Monomers copolymerizable with lactones that can be used in the present invention include oxirane compounds, lactams, cyclic siloxanes, cyclic urethanes, cyclic ureas, and alkyl vinyl ketones. Preferred are oxirane compounds,
Lactams and cyclic siloxanes. In particular,
Examples include ethylene oxide, propylene oxide, 1,2-butene oxide, styrene oxide, ε-caprolactam, hexamethylcyclotrisiloxane, and octamethylcyclotetrasiloxane.

Specific examples of the B-terminal binder used in the present invention include a compound represented by the general formula: Is used. General formula In the case of 1 = 2, there are adipic acid chloride, adipic acid bromide, adipic acid iodide, phthalic acid chloride, phthalic acid bromide and the like. In the case of 1 = 3, trimellitic acid chloride, 1 = 4 In the case of (1), pyromellitic acid chloride, pyromellitic acid bromide, and examples of the case where l is 5 or more include oligomers of acrylic acid chloride. Also As oxalyl chloride, One example is phosgene.

Preferred are acid chlorides, such as adipic acid chloride, phthalic acid chloride and pyromellitic acid chloride. The amount of the binder used is 0.5 to 2 equivalents, preferably 0.8 to 1.2 equivalents to 1 equivalent of the lithium atom at the terminal of the block copolymer.
Can be used in equivalent proportions. After completion of the B-terminal binding reaction, adding an acid or a base so that the reaction system becomes neutral
It is preferable to prevent depolymerization of B.

The block copolymer obtained by the reaction is recovered from the reaction solvent by a conventional separation method such as precipitation by addition of a coagulant such as methanol, stripping by steam, or removal of the solvent by a hot roll.

The block copolymer with improved impact resistance of the present invention can be used as a variety of practically useful products by processing methods such as injection molding and extrusion molding. Further, if necessary, an antioxidant, an ultraviolet absorber, a lubricant, a mold release agent, a coloring agent, various fillers and various thermoplastic resins such as general-purpose polystyrene, methacrylic resin, vinyl chloride resin, and styrene-butadiene block copolymer. Coalescing resin, polyacetal, polyphenylene ether resin, polycarbonate, nylon,
It can be used by mixing with polyethylene terephthalate, polybutylene terephthalate, styrene-methacrylate copolymer resin, styrene-maleic anhydride copolymer resin, acid-modified polyolefin, ionomer and the like.

[Examples] Examples will be shown below, and specific embodiments of the present invention will be described. However, these are intended to more specifically explain the purpose of the present invention and do not limit the present invention. .

Example 1 A stainless steel reactor having an internal volume of 10 was washed, dried, and sufficiently replaced with dry nitrogen. Then, 6000 g of benzene, 800 g of styrene, and 1.5 g of tetrahydrofuran were charged, and the temperature of the content was reduced while stirring the content. The temperature was raised to 70 ° C., the heating was stopped as soon as the temperature reached 70 ° C., and 18 mmol of n-butyllithium (cyclohexane solution) was added to initiate the polymerization of styrene. After 15 minutes, when the styrene monomer was almost completely consumed, the content was cooled so that the temperature of the content became 30 ° C., and after the temperature reached 30 ° C., 36 mmol of ethylene oxide was added, followed by stirring for 5 minutes. Next, raise the temperature of the contents to 30.
While maintaining at ℃, 200 g of ε-caprolactone was added.
After 15 minutes, when the ε-caprolactone monomer was almost completely consumed, after sampling the block copolymer AOB before the B-terminal binding reaction as a sample for analysis,
7 mmol of adipic acid chloride were added and stirring was continued for another 20 minutes. The polymer solution thus obtained was taken out of the reactor, 5 g of 2,6-di-tert-butyl-4-methylphenol and 5 g of tris (nonylphenyl) phosphite were added, and then dried with a hot roll. Thus, a block copolymer was obtained.

M of block copolymer AOB before B-terminal binding reaction
n, Mw, (Mw / Mn ) and block copolymer of B-terminus was coupled (content occupied in the composition of the A-O-B _n X is GPC
(Waters M-6000 type) under the following conditions.

Solvent: Tetrahydrofuran Column: Du Pont ZORBAX PSM 1000S2 PSM 1 Column temperature: 35 ° C Liquid sending flow rate: 0.7ml / min Liquid sending pressure: 1000psi Sample concentration: 1.0g / Sample liquid volume: 0.1ml Detector: Differential refraction Total (A-O-B _n X content was determined using GPC to (A-O-
Separating the B _n X and A-O-B, it was determined by the ratio of the area of the peak corresponding to each polymer on the chromatogram. The molecular weight is 1.4 × 1 as standard polystyrene.
0 ⁶ , 4.7 × 10 ⁵ , 1.1 × 10 ⁵ , 3.5 × 10 ⁴ , 8.5 × 10 ³ , 235 × 10 ³ I asked.

The styrene content in the obtained block copolymer was measured using an ultraviolet spectrophotometer (Hitachi UV-200).

The MI value of the obtained block copolymer was measured according to JIS K7210. Izod impact strength was measured according to JIS K 7110 using a 3.2 mm thick test piece produced by compression molding. Flexural modulus is the thickness produced by compression molding
It was measured according to ASTM D790 using a 3.2 mm test piece.

Examples 2 to 4 Examples 2 to 4 were prepared using styrene and ε-
The reaction was carried out in the same manner as in Example 1 except that the amount of caprolactone used and the polymerization time were changed.

Examples 5 and 6 In Examples 5 and 6, the amount of n-butyllithium, ethylene oxide styrene, lactone binder used, the polymerization temperature of lactone and the polymerization time were changed as shown in Table 1, and the others were carried out. The reaction was carried out as in Example 1.

Examples 7 to 12 In Examples 7 to 12, as shown in Table 1, Examples 7 to 12
In Example 9, phthalic acid chloride was used instead of adipic acid chloride as a binder, and in Examples 9 and 10, ε was used as a lactone as lactone.
Reaction was carried out in the same manner as in Example 1 except that δ-valerolactone was used instead of caprolactone, and in Examples 11 and 12, propylene oxide was used instead of ethylene oxide as a modifier.

Comparative Examples 1 and 2 In Comparative Examples 1 and 2, the amounts of styrene and lactone used and the polymerization time of lactone were changed as shown in Table 1, except that Example 1 was used.
The reaction was carried out in the same manner as described above. In Comparative Example 1, impact resistance was reduced when the styrene content was 90% or more, and in Comparative Example 2, rigidity (flexural modulus) was reduced when the styrene content was less than 10%.

Comparative Examples 3 to 5 The amount of n-butyllithium and the amount of the modifier as shown in Table 1 were used. In Comparative Example 3, no hydrochloric acid was used and 12 mm of hydrochloric acid was used.
ol was added to terminate the reaction, and Comparative Example 4 was performed in the same manner as in Example 1 except that 3.5 mmol of adipic acid chloride was added as a binder and Comparative Example 5 was added with 6.5 mmol of toluene diisocyanate (TDI). .

In Comparative Examples 3 and 4, the amount of the binder was insufficient, and in Comparative Example 5, the binder itself was not suitable.
The content of -B _n X is lowered impact resistance becomes less than 50%.

Comparative Example 6 The reaction was carried out in the same manner as in Example 1 except that the polymerization temperature of the lactone was changed to 100 ° C. As a result, since the polymerization temperature is high, (Mw / Mn) becomes larger than 3, and (A-O-B _n X
Was less than 50%.

Comparative Examples 7, 8 As shown in Table 1, the amounts of n-butyllithium, ethylene oxide, ε-caprolactone, adipic acid chloride, and the polymerization time of lactone were changed, and the others were the same as in Example 1.
The reaction was carried out in the same manner as described above.

As shown in Table 1, in Comparative Example 7, Mn of AOB was 5,000.
0, and the impact resistance was poor. In Comparative Example 8, AOB
Of Mn was higher than 500,000 and the workability was lowered.

Comparative Example 9 In the same manner as in Example 1, styrene was used as shown in Table 1.
The polymerization of styrene was carried out using 600 g of 18 mmol of n-butyllithium and then 9 mmo of ε-caprolactone as modifier.
l was added. After stirring at 30 ° C. for 5 minutes, 400 g of ε-caprolactone was added while the temperature was kept at 30 ° C. to polymerize the lactone. Twenty minutes later, 18 mmol of hydrochloric acid was added to terminate the polymerization. In this case, the structure of the main product polymer is PS: polystyrene block PCL: poly -ε- polycaprolactone block next, the impact resistance for a is (not a structure of A-O-B _n X object of the present invention is inferior.

Table 1 shows the polymerization conditions of Examples 1 to 12 and Comparative Examples 1 to 9 and the measurement results of the obtained block copolymer.

As can be seen from Table 1, the block copolymers of Examples 1 to 12 of the present invention have excellent impact resistance.

[Effects of the Invention] The block copolymer of the present invention is a very well-balanced one having improved impact resistance while maintaining excellent oil resistance and weather resistance, and has various types of processing methods such as injection molding and extrusion molding. It can be commercialized in a variety of ways, and has high utility value as automotive interior parts and electrical appliance housings.

Claims (1)

(57) [Claims] 1. A ring-opening of a polymer block A obtained by polymerizing a monomer mainly comprising a vinyl aromatic compound obtained by using an organolithium compound as an initiator and a monomer mainly comprising a lactone represented by the following general formula: Polymer block B obtained by polymerization R ₁ , R ₂ : hydrogen or an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkenyl group m: 2,4,5,6 The binding moiety is -O-
A block copolymer represented by the formula (CO-bonded), having the following properties (a) to (d): (A) the general formula (represented by _{A-O-B n X,} B terminal contains bonded block copolymer component at least 50 wt.% With a binder X:. Formula R ₃ : an aliphatic group having 1 to 20 carbon atoms, a cycloaliphatic group, an aromatic group l: a binder residue represented by an integer of 2 or more n: 2 or more and l or less (b) of the block copolymer The vinyl aromatic compound content is 10 to 90 when the melting point of the polymer block B exceeds 25 ° C.
90% by weight, above 55% by weight at 25 ° C or less
It is as follows. (C) The number average molecular weight of AOB is 5,000 to 500,000. (D) of AOB Is 3.0 or less.