JPS6047302B2 - Thermoplastic elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic elastomer composition having excellent flexibility, elasticity and moldability.

Block copolymer polyester elastomers (also called segment copolymer polyester elastomers), which have aromatic polyester units and aliphatic ether ester units and/or aliphatic polyester units in block form, have excellent moldability and are also heat resistant and oil resistant. It has come to be used for various purposes due to its excellent physical and mechanical properties. Typical uses include tubes, hoses, sheets, belts, wire coatings, various mechanical parts,
For example, it is used for seals, gaskets, O-rings, pipes, diaphragms, etc. Since it also has adhesive properties, it is also used as an adhesive for fibers, plastics, films, etc. Such polyester elastomers can have the above-mentioned properties varied over a fairly wide range by changing the combination of polyester components and the content of soft segments made of polyether ester or aliphatic polyester, making them suitable for a wide variety of applications. Attempts are being made to adapt. However, one of the major disadvantages of polyester elastomers is that it is difficult to make them elastic and flexible; for example, ordinary synthetic rubber has a durometer hardness of 25A to 60A.
However, even ester elastomers of 75A are difficult to manufacture and do not exhibit the softness of rubber. The reason why it is difficult to create flexibility in polyester elastomer is that in order to maintain a constant concentration of polyester crystals, which correspond to the crosslinking points of thermofusible rubber for comb elasticity, the amount of polyester hard segments must be increased to a certain level. Because of this, it is difficult to provide the same softness as ordinary rubber. The inventors of the present invention have conducted intensive studies with the aim of maintaining the moldability and excellent mechanical properties of polyester elastomer, and overcoming the drawback of polyester elastomer, its flexibility. It has been discovered that the above object can be achieved by blending, and the present invention has now been achieved.

That is, the present invention provides a thermofusible elastomer composition characterized in that a polyester elastomer and a high molecular weight syndiotactic 1,2-polybutadadiene are melt-blended.

The thermoplastic elastomer composition of the present invention is flexible, rich in rubber-like elasticity, and has high mechanical strength.

Moreover, a flexible rubber-like elastic body can be molded under thermoplastic molding conditions. In addition, compositions containing a large amount of syndiotactic 1,2-polybutadiene component exhibit improved properties in terms of heat resistance and mechanical strength. Another feature of the thermoplastic elastomer composition of the present invention is that both components have high affinity, and the blend thereof forms a well-dispersed system, making it possible to form a molded product with excellent transparency. This, together with its flexibility and excellent hygienic properties, makes it usable for medical purposes. In general, the polyester elastomer useful in the present invention has a high melting point crystalline hard segment A mainly composed of aromatic polyester units and a low melting point soft segment B mainly composed of aliphatic ether ester units a and/or aliphatic polyester units b. It is a block copolyester elastomer. Among these, the high melting point crystalline hard segment A, which is mainly composed of aromatic polyester units, is composed of dicarboxylic acid containing at least one component of aromatic dicarboxylic acid and glycol. Dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, adipic acid, sebacic acid, azelaic acid, taimaic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, bis(P-carboxyphenyl ) Methane, anthracenedicarboxylic acid, 4
, 4''-diphenyl ether dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, cyclohexane dicarboxylic acid, cyclopentanedicarboxylic acid, 4,4'-bicyclohexyl dicarboxylic acid, etc., especially mechanical properties, rubber elasticity, heat resistance. It is preferable to use an aromatic dicarboxylic acid containing at least 50 mol% of aromatic dicarboxylic acid, and in particular, from the viewpoint of affinity with polybutadiene, use of terephthalic acid or a mixture of terephthalic acid and isophthalic acid or phthalic acid gives preferable performance. The diol components constituting include aliphatic or alicyclic di4ols having 2 to 12 carbon atoms, namely ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6 −
These include hexanediol, decamethylene glycol, cyclohexanedimethanol, and mixtures thereof, but especially in terms of compatibility with syndiotactic 1,2-polybutadiene and the mechanical properties, chemical resistance, and heat resistance of the blended polymer. 1,4-butanediol is most preferred, followed by 1,6-hexanediol.

The ether unit a of the low melting point polymer segment B, which is a soft segment, is formed from polyalkylene glycol and a dicarboxylic acid component.
2-propylene glycol, poly(tetramethylene oxide) glycol, polyethylene glycol-polypropylene glycol block copolymer, polyethylene glycol-poly(tetramethylene oxide) glycol block copolymer, etc., especially poly(tetramethylene oxide) glycol. is preferable, and of course a combination of these is also possible.

The average molecular weight of these polyether glycols is approximately 30
It ranges from 0 to 6000. Further, the dicarboxylic acid component forming the ether ester unit a is the same as that exemplified as the dicarboxylic acid component of the ester unit of the polyester hard segment A. aliphatic polyester unit b
Examples include those formed from aliphatic dicarboxylic acids and diols and polylactones, and among the above-mentioned dicarboxylic acids, long-chain dicarboxylic acids such as dimer acids are included in addition to aliphatic dicarboxylic acids and alicyclic dicarboxylic acids. .

Polylactones include polyε-caprolactone,
Examples include polyenanthlactone, polycaprylolactone, and poly[delta]-valerolactone. The molecular weight of such aliphatic polyester unit b is also about 300 to 100.
00, preferably 500 to 3000, and is block copolymerized with polyester hard segment A. A block copolymer consisting of a high melting point crystalline ester hard segment A and a low melting point aliphatic polyester unit b can be obtained by, for example, producing polybutylene terephthalate and polyethylene sebacate by a known polymerization method, and then transesterifying the polyesters with each other in the presence of a transesterification catalyst. It can be obtained by melt-kneading the mixture and causing a blocking reaction. The composition ratio of hard segment A and soft segment B in the polyester block copolymer used in the present invention is 10/90 to 95/5 by weight, and this composition ratio is determined by the syndiotactic 1, The blending ratio with 2-polybutadiene can be changed as appropriate depending on the intended use and required performance.

Particularly suitable elastomer compositions are obtained in which the soft segment accounts for 15 to 80% by weight at a glass temperature below room temperature, and the melting point of the total copolyester is 100 to 2.
A temperature of 20°C is recommended. Problems such as decomposition may occur when polyester elastomers are blended with syndiotactic 1,2-polybutadiene whose melting point exceeds 220°C, and if the melting point is lower than 100°C, it may not be possible to achieve the soft and rubbery properties that are the object of the present invention. It is not possible to form a molded article with excellent properties and heat resistance. In addition, it is preferable that the degree of polymerization of the polyester elastomer is high from the viewpoint of mechanical properties, but if it is too high, the moldability will decrease, and in particular, the compatibility with syndiotactic 1,2-polybutadiene and the compounding processability will decrease. Therefore, in terms of intrinsic viscosity, it is approximately 0.5 to 4.0,
The number average molecular weight is preferably in the range of about 10,000 to 5,000 degrees. Particularly preferred compositions of the polyester elastomer include polybutylene terephthalate-poly(tetramethylene oxide) glycol, polybutylene terephthalate-polybutylene isophthalate-poly(tetramethylene oxide) glycol, and polybutylene terephthalate-polybutylene phthalate-poly(tetramethylene oxide) glycol. ) glycol, polybutylene terephthalate-polyhexamethylene terephthalate-polyethylene glycol, polyhexamethylene terephthalate-poly(tetramethylene oxide) glycol, polybutylene terephthalate-polybutylene dimerate, etc.

Note that polyfunctional components such as polycarboxylic acids, polyols, and polyoxycarboxylic acids may be added to the polyester elastomer depending on the case. By adding such polyfunctional components, the polyester elastomer can be improved. It is also possible to achieve a good state of dispersion and compatibility with syndiotactic 1,2-polybutadiene by increasing the melt viscosity.

The amount of the polyfunctional component that can be added is 5.0 mol % or less, preferably 3.0 mol % or less, based on the dicarboxylic acid and diol components forming the polymer. Examples of substances that can be used as polyfunctional components include trimellitic acid, trimesic acid, pyromellitic acid, benzophenonetetracarboxylic acid, butanetetracarboxylic acid and derivatives such as their acid esters and acid anhydrides, glycerin, pentaerythritol, etc. Can be mentioned. It is also effective to partially modify the polyester elastomer with an isocyanate compound or an epoxy compound.

Isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4''
-diphenylmethane diisocyanate, 4,4″-diphenyl ether diisocyanate, hexamethylene diisocyanate, m- or P-xylylene diisocyanate, and dimers thereof,
Contains multimers such as trimers. Epoxy compounds have one or two epoxy groups in the molecule, and β. γ-epoxypropyl ether, 1,4-
Bis(β.γ-epoxypropoxy)butane, 1,6-
Bis(epoxyethyl)hexane, 2,2-bis[P-
(β.γ-epoxypropoxy)phenyl]propane,
1-Epoxyethyl-3,4-epoxycyclohexane, 1-(β.γ-epoxypropoxy)-2-benzyloxyethane, 1-(β.γ-epoxypropoxy)2
-ethoxyethane, 1,4-bis(β.γ-epoxypropoxy)benzene, etc., and particularly preferred are epoxy compounds having the following structure. (However, n is an integer.) On the other hand, the syndiotactic 1,2-polybutadiene constituting another component of the thermoplastic elastomer composition of the present invention has a steric configuration that is regularly arranged in a syndiotactic manner. 1,2-polybutadiene containing 90% or more of 1,2-bonds, a crystallinity of 10-30%, and an average molecular weight of 50,000 or more, preferably 100,000.
It is a high molecular weight substance.

Ordinary polybutadiene containing primarily 1,4-bonds is unfavorable in terms of compatibility and mechanical properties.

As such high molecular weight syndiotactic 1,2-polybutadiene, JSRRB8L from Japan Synthetic Rubber Co., Ltd.
O and JSRRB82O are available commercially. In addition, these polymers may have functional groups such as 0H, COOH, NCO, and COOR groups introduced into their molecular structures, and some of the branched vinyl groups may be hydrogenated, halogenated, or epoxidized. It can be used even if modified such as. The thermoplastic elastomer composition of the present invention includes:
Polyester elastomer and syndiotactic technology 1,
It contains more than about 50% by weight and less than 90% by weight of syndiotactic 1,2-polybutadiene based on the total weight of 2-polybutadiene.

More than about 50% by weight and less than 60% by weight, especially 60-80% by weight
A blend containing syndiotactic 1,2-polybutadiene is syndiotactic. The heat resistance and mechanical properties of 1,2-polybutadiene can be improved.

Therefore, improved performance can be imparted to films, footwear soles, tubes, hoses and various rubber products. In addition, polyester elastomer and syndiotactic technology 1, 2
- Polybutadiene blends have high utility value as adhesives such as hot melt adhesives and solution coatings, and those whose main component is polyester elastomer are useful as adhesives for textiles, metals, rubber, etc. Yes, syntheta geotactic 1,
Incorporation of 2-polybutadiene improves adhesion and fluidity at low temperatures, thus modifying the polyester elastomer adhesive for textiles.

On the other hand, syndiotactic 1,2-polybutadiene is used as an adhesive for various types of woven fabrics, paper, leather, wood boards, etc., but blending with polyester elastomer can improve adhesive properties and adhesive strength at high temperatures. Suitable mixing equipment used to prepare the thermoplastic elastomer compositions of the present invention include single or twin screw extruders, Panbury mixers, rubber roll machines, kneaders, and the like.

A particularly advantageous method for preparing the compositions of the invention is to dry mix polyester elastomer pellets or powders with syndiotactic 1,2-polybutadiene pellets or powders, and then heat-melt mix them in the mixing apparatus described above. It's a method. Alternatively, instead of preparing melt-mixed pellets in advance, a suitable amount of polybutadiene pellets may be introduced into the polyester elastomer pellets in the barrel of an extruder or injection molding machine immediately before extrusion or injection molding of the polyester elastomer. The elastomer composition of the present invention may optionally contain antioxidants such as hindered phenol compounds, aromatic amine compounds, phosphate ester compounds, and phosphite compounds.
Heat resistance and light resistance can be further improved by adding a heat resistant agent and a UV absorber such as a benzophenone compound, a benzotriazole compound, a benzothiazole compound, or a hindered amine compound.

Furthermore, the composition of the present invention includes a nucleating agent, a lubricant, a mold release agent, an antistatic agent, a reinforcing material, carbon black, various fillers, a blowing agent,
It is also possible to improve some of the properties by containing additives such as dyes and pigments.

The compounded composition of the present invention is usually applied to a molding machine in the form of pellets, but it may of course be in the form of powder or grams.Also, as an adhesive, it can be applied to an applicator in various forms, but a special form is polyester elastomer. The same effect can be obtained by blending the solution and the polybutadiene solution under conditions that they are mutually soluble. Examples of the present invention will be specifically described below.

Note that all parts in the examples mean parts by weight. Example 1 126 parts of dimethyl terephthalate, 68 parts of dimethyl isophthalate, 60 parts of poly(tetramethylene oxide) glycol having a number average molecular weight of about 1000, and 135 parts of 1,4-butanediol were mixed with 0.1 parts of titanium tetrabutoxide catalyst.
It was charged into a reaction vessel along with 0 part of the methanol and heated at 210°C for 2 hours to distill off methanol.

The reaction mixture was then added with '6 Irganox' 10100.
63 parts were added and polymerized under the conditions of 245° C. and 0.2 TI$LHg. Obtained polybutylene terephthalate-polybutylene isophthalate-poly(tetramethylene oxide) glycol [polyester elastomer A]
The melting point was 163°C1 and the intrinsic viscosity was 1.20. The above polyester elastomer A (5JSRRB810(
Syndiotactic 1,2-polybutadiene, number average molecular weight >100,000; manufactured by Japan Synthetic Rubber Co., Ltd.) was melt-blended using an extruder at 190° C. at various blend ratios shown in Table 2.

Claims (1)

[Claims] 1. A thermofusible elastomer composition characterized in that 10% by weight or more but less than 50% by weight of a polyester elastomer and more than 50% by weight but not more than 90% by weight of high molecular weight syndiotactic-1,2-polybutadiene are melt-blended. .