JPH0751648B2 - Elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electric wire coating, a belt, an automobile part, a tube,
The present invention relates to an elastomer composition used as an elastic material for tires, industrial products, etc., which is a mixture of a vulcanizable rubber component and an aliphatic polyester.

(Prior Art) Natural rubber and synthetic rubber have excellent flexibility and elasticity and are used as various industrial materials. However,
These rubber materials are inferior in mechanical strength, heat resistance, oil resistance, and chemical resistance, so that their use range is limited. From such a background, it is desired to develop an industrial material which is excellent in heat resistance, mechanical strength, oil resistance and chemical resistance while retaining the flexibility and elasticity of rubber.

Various improvements have been proposed for these problems.
As a typical method, a method of adding various reinforcing agents, fillers, and stabilizers to various rubbers has been proposed, but this method is a partial improvement in the above physical properties and is a satisfactory elastomer. The composition could not be obtained.

It has also been proposed to blend other polymers with the rubber. For example, JP-A-60-31545 proposes an elastomer composition in which a rubber is blended with a polyester elastomer having a crystalline aromatic polyester segment and a polylactone segment. This elastomer composition was improved in heat resistance, weather resistance and oil resistance, but was insufficient in improving mechanical strength, particularly tensile elongation at break.

(Problems to be Solved by the Invention) The present invention has been made to solve such problems, and an object thereof is to provide a rubber and a polyester elastomer having a crystalline aromatic polyester segment. Is to provide an elastomer composition excellent in heat resistance, oil resistance, chemical resistance and mechanical strength in addition to the flexibility and elasticity of rubber.

(Means for Solving the Problem) The inventors of the present invention have conducted extensive studies on polyester elastomers to be mixed with rubber, and as a result, have properties as an elastomer, excellent heat resistance and mechanical properties, and molding processability. The present invention has been completed by finding an aliphatic polyester which is also excellent in the above and blending it with rubber.

That is, the elastomer composition of the present invention comprises: (A) 5 to 85% by weight of a vulcanizable rubber component; (B) an aliphatic dicarboxylic acid represented by the following formula [I], an aliphatic diol, And 95 to 15% by weight of an aliphatic polyester having at least one of a dihydroxy compound represented by the following formula [II] and a monohydroxy compound represented by the following formula [III] as a constituent. ， By that, the above-mentioned object is achieved.

HOOC- (CH ₂₎ n-COOH (I) (wherein, n represents an integer of 0.) (In the formula, R ¹ and R ² independently represent an alkylene group, p is 3 or 4, and q and r independently represent 0 or an integer of 1 or more.) (In the formula, R ³ represents an alkylene group, l is 2 or 3, and
m represents 0 or an integer of 1 or more. [Aliphatic Polyester] When a dicarboxylic acid having more than 10 carbon atoms is used in the above aliphatic dicarboxylic acid, the physical properties of the molded product obtained from the aliphatic polyester are deteriorated. As the dicarboxylic acid, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid are preferably used.

Examples of the aliphatic diol include glycol and polyalkylene oxide. Examples of the glycol include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3
-Butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, cyclopentane-1 , 2-diol, cyclohexane-1,2-
Examples include diol, cyclohexane-1,3-diol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, which may be used alone or in combination of two or more. .

Examples of the polyalkylene oxide include polyethylene oxide, polypropylene oxide, polytetramethylene oxide, polyhexamethylene oxide and the like, and these may be used alone or in combination of two or more kinds. When the number average molecular weight of polyalkylene oxide is small, the ability to impart flexibility to the resulting aliphatic polyester is reduced, and when it is too large, physical properties such as thermal stability of the obtained aliphatic polyester are reduced. ~ 20,000, preferably 500 ~ 50
00.

The dihydroxy compound represented by the above formula [II] is a low molecular weight compound exhibiting liquid crystallinity, the alkylene groups R ¹ and R ² are preferably ethylene groups or propylene groups, and q and r are 0 or 1
Is preferred, and 4,4 "-dihydroxy-p-terphenyl represented by the following formula [A] and 4,4-" represented by the following formula [B]
Dihydroxy-p-quaterphenyl and the following formula [C]
4,4-di (2-hydroxyethoxy) -p represented by
-Quarterphenyl and the like are preferably used.

The transition temperature of 4,4 ″ -dihydroxy-p-terphenyl [A] from the crystalline state to the liquid crystal state is 260 ° C., and that of 4,4-dihydroxy-p-quarterphenyl [B] is 336.
C., that of 4,4-di (2-hydroxyethoxy) -p-quaterphenyl [C] is 403.degree. The liquid crystal state means a state in which the compound is in a molten state and the molecules maintain the alignment state. The above dihydroxy compounds [II] may be used alone or in combination.

Liquid crystal molecules generally have high crystallinity.
4 "-dihydroxy-p-terphenyl [A], 4,4-
Dihydroxy-p-quaterphenyl [B] and 4,4
-Di (2-hydroxyethoxy) -p-quaterphenyl [C] has a high transition point from the crystal to the liquid crystal state. Therefore, when these dihydroxy compounds [II] are incorporated into the polymer chain, Indicates a unique property.

That is, since the dihydroxy compound [II] shows crystallinity and its transition point is high, the dihydroxy compound [II]
Even if the compounding amount of is small, it forms a strong and heat-resistant physical crosslink. As a result, it is presumed that a thermoplastic elastomer having high heat resistance can be obtained without impairing the flexibility derived from the soft segment.

The monohydroxy compound represented by the above formula [III] is a rigid low-molecular compound having a paraphenylene skeleton,
The melting points of these compounds are extremely high, reflecting the characteristic molecular structure. Furthermore, it is known that the para-phenylene skeleton is effective as a mesogen for low molecular weight liquid crystal compounds, and it has a strong cohesive force not only in the solid state but also in the high temperature state (molten state). Is shown. Therefore, the above monohydroxy compound [II
When [I] is incorporated into the polymer terminal, it results in very strong physical crosslinks with high heat resistance, and a thermoplastic elastomer with excellent heat resistance is produced.

In the monohydroxy compound represented by the above formula (III), R ³ is preferably an ethylene group or a propylene group, and m
Is preferably 0 or 1. Examples of the above monohydroxy compound include 4-hydroxy-p-terphenyl, 4-
Examples thereof include hydroxy-p-quaterphenyl, 4- (2-hydroxyethoxy) -p-terphenyl, 4- (2-hydroxyethoxy) -p-quaterphenyl and the like. The monohydroxy compounds [III] may be used alone or in combination.

Polysilicone having two hydroxyl groups and lactone in an aliphatic polyester composed of at least one of the above aliphatic dicarboxylic acid [I], aliphatic diol and dihydroxy compound [II] and monohydroxy compound [III] Alternatively, aromatic hydroxycarboxylic acid may be contained as a constituent component.

The lactone is a compound that opens a ring and reacts with an acid and a hydroxyl group to add an aliphatic chain, which imparts flexibility to the polyester, and which has 4 or more carbon atoms in the ring. It is preferably a 5-membered ring to a 8-membered ring, more preferably ε-caprolactone, δ-valerolactone,
γ-butyrolactone and the like can be mentioned.

The aromatic hydroxycarboxylic acid imparts rigidity and liquid crystallinity to the polyester, and includes salicylic acid, metahydroxybenzoic acid, parahydroxybenzoic acid, 3-chloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxyl. Benzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3-methyl-4-hydroxybenzoic acid, 3-phenyl-4-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4'-carboxy Biphenyl and the like can be mentioned, with preference given to parahydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, and 4-hydroxy-4'-carboxybiphenyl.

Further, the above aliphatic polyester may contain an aromatic diol other than the dihydroxy compound [II] or an aromatic dicarboxylic acid as a constituent component in order to improve the mechanical properties of the polyester.

Examples of the aromatic diol include hydroquinone, resorcin, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl ether,
4,4'-dihydroxydiphenyl sulfide, 4,4'-
Dihydroxydiphenyl sulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1,1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-hydroxyphenoxy) ethane, 1 Examples thereof include 4,4-dihydroxynaphthalene and 2,6-dihydroxynaphthalene.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, metal salts of 5-sulfoisophthalic acid, 4,4'-dicarboxybiphenyl, 4,4'-dicarboxydiphenyl ether, 4,4'-dicarboxydiphenyl sulfide. ,
4,4'-dicarboxydiphenyl sulfone, 3,3'-dicarboxybenzophenone, 4,4'-dicarboxybenzophenone, 1,2-bis (4-carboxyphenoxy) ethane, 1,4-dicarboxynaphthalene, or 2,6-dicarboxynaphthalene and the like can be mentioned.

The aliphatic polyester composed of the above dihydroxy compound [II], an aliphatic diol and an aliphatic dicarboxylic acid has a lower dihydroxy compound [II] content, lowering the heat resistance, and a higher content of the dihydroxy compound [II] results in a higher elastic modulus and flexibility. Drop,
Since it becomes unsuitable as a thermoplastic elastomer, the content of the dihydroxy compound [II] is preferably 0.1 to 30 mol% in all monomers constituting the polyester, more preferably 0.5 to 20 mol%. Preferably
It is 1.0 to 10 mol%. When polyalkylene oxide or polysilicone is used as a diol other than aromatic, its constituent unit is counted as one monomer. That is,
Polyethylene oxide with a degree of polymerization of 10 is counted as 10 monomers.

Further, in the aliphatic polyester composed of the monohydroxy compound [III], the aliphatic diol and the aliphatic dicarboxylic acid, the heat resistance is decreased when the content of the monohydroxy compound [III] is decreased, and the molecular weight of the aliphatic polyester is increased when the content of the monohydroxy compound [III] is increased. Does not increase sufficiently and the physical properties are inferior, so 0.1 to 2% of all monomers constituting the aliphatic polyester
It is preferably 0 mol%. Further, the aliphatic polyester composed of the dihydroxy compound [II], the monohydroxy compound [III], the aliphatic diol and the aliphatic dicarboxylic acid is a hydroxy compound obtained by combining the dihydroxy compound [II] and the monohydroxy compound [III]. When the content is low, the heat resistance is lowered, and when it is high, the flexibility is not lowered and a sufficient increase in the molecular weight cannot be obtained. Therefore, it is preferably 0.1 to 30 mol% in all the monomers constituting the aliphatic polyester. In this case, the ratio of the dihydroxy compound [II] and the monohydroxy compound [III] is preferably in the range satisfying 0 <[III] / [II] + [III] <2/3.

The aliphatic polyester composed of the above components is
It can be produced using any of the generally known polycondensation methods listed below.

A method in which a dicarboxylic acid and a diol component (including an aliphatic diol, a dihydroxy compound, a monohydroxy compound, etc.) are directly reacted.

A method of reacting a lower ester of dicarboxylic acid and a diol component by transesterification.

A method of reacting a dicarboxylic acid halide and a diol component in a suitable solvent such as pyridine.

A method of reacting a metal alcoholate of a diol component with a dicarboxylic acid halide.

A method of reacting an acetylated diol component and a dicarboxylic acid by transesterification.

It is also possible to control the structure of the polyester obtained by changing the order of addition of the dihydroxy compound [II] during polymerization. For example, dihydroxy compound [I
When [I], dicarboxylic acid and other diol components are charged together, a random copolymer is easily obtained,
When the dihydroxy compound [II] is charged in the latter stage of the polymerization, it becomes easy to obtain a block copolymer. In addition, a polyester synthesized in advance is kneaded with the dihydroxy compound [II] or an acetyl compound of the dihydroxy compound under reduced pressure heating, and a segment based on the dihydroxy compound [II] is introduced into the molecular chain by deethylene glycol or transesterification reaction. Is also possible.

In the polycondensation, a catalyst generally used in producing polyester may be used. As the catalyst, lithium, sodium, potassium, cesium, magnesium, calcium, barium, strontium, zinc, aluminum, titanium, cobalt, germanium,
Examples include metals such as tin, lead, antimony, arsenic, cerium, boron, cadmium, and manganese, organometallic compounds thereof, organic acid salts, metal alkoxides, metal oxides, and the like.

Particularly preferred catalysts are calcium acetate, diacyl stannous tin, tetraacyl stannic tin, dibutyltin oxide, dibutyltin dilaurate, dimethyltin arelate, tin dioctanoate, tin tetraacetate, triisobutylaluminum, tetrabutyltitanate, germanium dioxide, and tris. It is antimony oxide. Two or more kinds of these catalysts may be used in combination. In addition, water, alcohol, glycol, etc., which are by-products of polymerization, are efficiently distilled off,
In order to obtain a high molecular weight polymer, the reaction system is
It is preferable to reduce the pressure to 1 mmHg or less. The reaction temperature is generally 150-350 ℃.

[Vulcanizable Rubber Component] The vulcanizable rubber component includes natural rubber and synthetic rubber. As the synthetic rubber, most commercially available synthetic rubber can be used. For example, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), acrylonitrile-butadiene rubber (NBR),
Examples include chloroprene rubber (CR), isobutylene-isoprene rubber (IIR), urethane rubber, and polysulfide rubber. These vulcanizable rubber components may be partially vulcanized.

The elastomer composition of the present invention is obtained by blending these vulcanizable rubber components and the above aliphatic polyester in a predetermined ratio and mixing them. The vulcanizable rubber component is used in a proportion of 10 to 85% by weight based on the elastomer composition. 10% by weight
Below the temperature, the rubber-like elasticity of the resulting composition becomes insufficient,
If it exceeds 5% by weight, the oil resistance of the elastomer composition,
Heat resistance and chemical resistance decrease.

Various methods may be used to mix the aliphatic polyester as the vulcanizable rubber component, such as rolls, kneaders,
It can be performed using a Hanbury mixer, an extruder, a plastograph, or the like.

Further, in the elastomer composition of the present invention, in order to vulcanize the vulcanizable rubber component contained in the composition, a general vulcanizing agent, vulcanization accelerator, etc. can be used. Vulcanizing agents include sulfur compounds such as powdered sulfur and colloidal sulfur;
And peroxides such as p-quinone dioxime, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, and 1,4-bis (t-butylperoxyisopropyl) benzene. These vulcanizing agents are
It is preferably used in an amount of 0.1 to 5% by weight based on the vulcanizable rubber component. Vulcanization accelerators include n-butyraldehyde aniline, 1,3-diphenylguanidine, N, N'-diphenylthiourea. Further, a mastication accelerator, a scorch inhibitor, a tackifier, a processing aid, carbon black and the like may be added.

In addition, the following additives may be added to the elastomer composition of the present invention within a range that does not impair practicality. Examples of the additive include glass fiber, carbon fiber, boron fiber, silicon carbide fiber, alumina fiber, amorphous fiber, inorganic fiber such as silicon / titanium / carbon fiber, organic fiber such as aramid fiber, calcium carbonate, and oxidation. Titanium, mica,
Inorganic fillers such as talc, triphenyl phosphite, trilauryl phosphite, trisnonyl phenyl phosphite, 2-tert-butyl-α- (3-tert-butyl-4
-Hydroxyphenyl) -p-cumenylbis (p-nonylphenyl) phosphite and other heat stabilizers, hexabromocyclododecane, tris- (2,3-dichloropropyl)
Flame retardants such as phosphate and pentabromophenyl allyl ether, p-tert-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,
UV absorbers such as 4,5-trihydroxybutyrophenone, butylhydroxyanisole, butylhydroxytoluene, distearylthiodipropionate, dilaurylthiodipropionate, antioxidants such as hindered phenol antioxidants, N, N-bis (hydroxyethyl)
Antistatic agents such as alkyl amines, alkyl allyl sulfonates, alkyl sulfanates, inorganic substances such as barium sulfate, alumina, silicon oxide; higher fatty acid salts such as sodium stearate, barium stearate, sodium palmitate; benzyl alcohol, benzophenone, etc. Examples of the organic compounds include highly crystallized polyethylene terephthalate, polytrans-cyclohexane dimethanal terephthalate, and other crystallization accelerators.

(Example) Below, this invention is demonstrated based on an Example.

Example 1 Synthesis of aliphatic polyester (B): Dimethyl adipate 26 was placed in a glass flask having an inner volume of 2 equipped with a stirrer, a thermometer, a gas blowing port and a distillation port.
8.2g, ethylene glycol 313.6g and 4,4-dihydroxy-p-quaterphenyl (hereinafter referred to as DHQ) 60.9
g monomer mixture, as well as calcium acetate as catalyst
0.4 g and 0.13 g germanium oxide were added. After replacing the inside of the flask with nitrogen, the temperature was raised to 180 ° C. to carry out the transesterification reaction. Methanol was distilled off along with the reaction. It took about 2 hours until the transesterification reaction was completed, and stirring was continued for the whole period. Next, the temperature inside the flask was raised to 300 ° C., and stirring was continued for 30 minutes in that state, ethylene glycol was distilled out, and the reaction mixture became uniform. The polycondensation reaction was carried out for 2 hours while the pressure inside the flask was reduced to 1 mmHg or less. A very viscous white resin was obtained. The intrinsic viscosity of this resin was 1.0.

The aliphatic polyester (B) obtained above and commercially available SB
R rubber (JSR SBR1500, manufactured by Japan Synthetic Rubber Co., Ltd.) (A) was mixed at a weight ratio of 5 to 5, and melt-mixed at 200 ° C. for 30 minutes using a plastograph. In the resulting mixture,
Sulfur as a vulcanizing agent is 1.75% by weight with respect to the rubber component,
0.5% by weight of 1,3-diphenylguanidine as a vulcanization accelerator was added to the rubber component and kneaded at 100 ° C for 15 minutes to obtain an elastomer composition. Next, the obtained elastomer composition was press-vulcanized at 145 ° C. for 35 minutes by a pressure press to obtain a molded body. In addition, JSR SBR1500 has 2
3.5%, Mooney viscosity 52ML _{1 + 4} (100 ℃).

The following evaluation test was performed on the obtained molded body.

(A) Tensile elongation test It was measured according to JIS K6301 using a No. 3 dumbbell. Shimazu Autograph AG5000B was used as the tensile tester.

(B) Oil resistance test The molded body was immersed in JIS No. 3 oil at 70 ° C for 70 hours, and the volume change rate (%) of the molded body after the immersion was measured before the test.

(C) Chemical resistance test The No. 3 dumbbell was immersed in benzene, toluene, and a 20% NaOH aqueous solution at 23 ° C. for 5 days, and the No. 3 dumbbell was taken out from each liquid and the surface condition was observed. The chemical resistance was divided into ranks A to D based on the change in surface condition.
The results are shown in Table 2.

Example 2 As the vulcanizable rubber component of Example 1, a commercially available NBR rubber (JSR
A molded article of an elastomer composition was obtained in the same manner as in Example 1 except that NBR N240, manufactured by Nippon Synthetic Rubber Co., Ltd. (A) was used. An evaluation test was performed on the obtained molded body in the same manner as in Example 1. The results are shown in Tables 1 and 2. Note that JSR NBR N240 is a bonded acrylonitrile 26
%, Mooney viscosity 56 ML _{1 + 4} (100 ° C), specific gravity 0.96.

Comparative Examples 1 and 2 Comparative Examples 1 and 2 are the rubber components used in Examples 1 and 2, namely SBR rubber (JSR SBR 1500, manufactured by Nippon Synthetic Rubber Co., Ltd.).
(A) and NBR rubber (JSR NBR N240, manufactured by Nippon Synthetic Rubber Co., Ltd.) (A) were subjected to the same vulcanization operation as in Example 1 to obtain a molded body. An evaluation test was conducted on this molded article in the same manner as in Example 1. The results are shown in Tables 1 and 2.

However, in the table, A means no change in the surface condition, B: almost no change in the surface condition, C: slightly swelled surface, D: fragile due to swelling.

As can be seen from Table 1, the molded products (Examples 1 and 2) obtained from the elastomer composition of the present invention in which the rubber component (A) and the aliphatic polyester (B) were mixed were molded products composed only of the rubber component. Compared with (Comparative Examples 1 and 2), tensile elongation at break and oil resistance are excellent. Further, as can be seen from Table 2, the molded articles (Examples 1 and 2) obtained from the elastomer composition of the present invention were benzene, toluene, and
Almost no change was observed in the surface state of the molded product with any solvent of 20% NaOH aqueous solution, and the oil resistance was superior to the molded products composed only of the rubber component (Comparative Examples 1 and 2).

(Effects of the Invention) As described above, the elastomer composition of the present invention comprises the vulcanizable rubber component (A), an aliphatic compound having high crystallinity and a segment based on a dihydroxy compound or monohydroxy compound having a high melting point. Since it contains polyester (B), it has properties as an elastomer, and at the same time, a molded product having excellent heat resistance, oil resistance, chemical resistance and mechanical strength can be obtained. Suitable for tires and various industrial products.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Niki 2-2 Hyakusan, Shimamoto-cho, Mishima-gun, Osaka (72) Inventor Torasuke Saito 5-17-21 Yamatedai, Ibaraki-shi, Osaka (72) Inventor Hiroki Kadomachi 1-11-3 Minami Kasugaoka, Ibaraki City, Osaka Prefecture (72) Inventor Daishiro Kishimoto 2-11-20 Mishimaoka, Ibaraki City, Osaka Prefecture Umeyama Mansion 102 (56) Reference Japanese Patent Laid-Open No. 60-31545 (JP, A)

Claims (1)

[Claims] (A) 5 to 85% by weight of a vulcanizable rubber component; (B) an aliphatic dicarboxylic acid represented by the following formula [I], an aliphatic diol, and An elastomer composition containing 95 to 15% by weight of an aliphatic polyester containing at least one of a dihydroxy compound represented by II] and a monohydroxy compound represented by the following formula [III] as a constituent. HOOC- (CH ₂₎ n-COOH (I) (wherein, n represents an integer of 0.) (In the formula, R ¹ and R ² independently represent an alkylene group, p is 3 or 4, and q and r independently represent 0 or an integer of 1 or more.) (In the formula, R ³ represents an alkylene group, l represents 2 or 3, and m represents an integer of 0 or 1 or more.)