JP2009126906A - Polyester elastomer resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester elastomer resin composition having good abrasion resistance, giving good molded product surface appearance, and excellent in mechanical properties as well. <P>SOLUTION: The polyester elastomer resin composition comprises 86-99.95 wt.% of a polyester elastomer (A) composed mainly of (a1) high-melting crystalline polymer segments composed mainly of crystalline aromatic polyester units and (a2) low-melting polymer segments composed mainly of aliphatic polyether units and/or aliphatic polyester units and 0.05-14 wt.% of a polymer (B) made from (b1) a silicone compound and (b2) an ethylene copolymer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyester elastomer resin composition having excellent wear resistance and molded product surface appearance and excellent mechanical properties.

  A polyester elastomer having a crystalline aromatic polyester unit as a hard segment and an aliphatic polyether unit such as poly (alkylene oxide) glycol and / or an aliphatic polyester unit such as polylactone as a soft segment has strength and impact resistance. It is widely used in the fields of automobiles, electrical / electronic parts, consumer goods, etc. because it has excellent mechanical properties such as elastic recovery and flexibility, low temperature and high temperature characteristics, and is thermoplastic and easy to process. ing.

  When abrasion resistance is required in these applications, a method of adding an abrasion resistance improver to a polyester elastomer is known, a method of adding a silicone resin (Patent Document 1), and adding a silicone oil (Patent Document 2), a method of adding fluororubber (Patent Document 3), and a method of adding saturated aliphatic hydrocarbon group-substituted amide (Patent Document 4) have been proposed. Further, as a method of adding two or more kinds of wear resistance improvers, a method of adding a silicone resin having a molecular weight of 10,000 or more and a reactive silicone oil (Patent Document 5), a solid lubricating oil, a higher alcohol, a higher fatty acid and derivatives thereof And a method of adding a long-chain hydrocarbon compound (Patent Document 6) and a method of adding potassium titanate whiskers and substituted amides (Patent Document 7). Furthermore, a method for improving abrasion resistance by allowing a polyolefin elastomer to exist as a domain in a polyester elastomer matrix has also been proposed (Patent Document 8).

However, since these abrasion resistance improvers have poor compatibility with the polyester elastomer, when they are added to the polyester elastomer, delamination of the surface of the molded product, generation of weld lines, and poor surface appearance due to blooming. In addition, when potassium titanate whiskers are added, the tensile elongation at break is greatly reduced and the mechanical properties of the polyester elastomer are impaired. Furthermore, it is difficult to obtain sufficient wear resistance even when a polyolefin elastomer is present as a domain.
Japanese Patent Laid-Open No. 3-229753 JP-A-61-195154 JP-A-9-157500 method JP-A-5-279557 Japanese Patent No. 3531691 JP 52-65552 A JP 2007-146076 A JP 2003-292745 A

  An object of the present invention is to solve the above-mentioned problems in the prior art, and the object is to improve the abrasion resistance of the polyester elastomer and the appearance of the surface of the molded article, and also have excellent mechanical properties. The object is to provide an elastomer resin composition.

  That is, the present invention refers to (1) a high melting point crystalline polymer segment (a1) mainly composed of crystalline aromatic polyester units, and a low melting point polymer segment mainly composed of aliphatic polyether units and / or aliphatic polyester units. Polyester elastomer (A) having (a2) as the main constituent (A) 80 to 99.95% by weight, polymer (B) composed of silicone compound (b1) and ethylene copolymer (b2) 0.05 to 20% by weight % Polyester elastomer resin composition.

Moreover, following (2)-(4) is a preferable aspect.
(2) The copolymerization amount of the low-melting polymer segment (a2) of the polyester elastomer (A) is 10 to 90% by weight,
(3) The polymer (B) is a graft copolymer of 20 to 80% by weight of a silicone compound and 20 to 80% by weight of an ethylene copolymer,
(4) Furthermore, 0.01 to 40 parts by weight of the silicone compound (b1) alone and 0.01 to 40 parts by weight of the ethylene copolymer (b2) are contained per 100 parts by weight of the polymer (B). That it is.

  According to the present invention, as described below, it is possible to obtain a polyester elastomer resin composition that is excellent in wear resistance and the surface appearance of a molded product, and also excellent in mechanical properties.

  Hereinafter, the present invention will be described in detail.

  The high-melting crystalline polymer segment (a1) of the polyester elastomer (A) used in the present invention is a polyester mainly formed from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, anthracene dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid. Acid, diphenoxyethane dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, sodium 3-sulfoisophthalate and the like. Although aromatic dicarboxylic acid is mainly used, if necessary, a part of the aromatic dicarboxylic acid may be converted to alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, 4,4′-dicyclohexyldicarboxylic acid, etc. Alternatively, it may be substituted with an aliphatic dicarboxylic acid such as adipic acid, succinic acid, oxalic acid, sebacic acid, dodecanedioic acid, and dimer acid. Of course, ester-forming derivatives of dicarboxylic acids such as lower alkyl esters, aryl esters, carbonates, and acid halides can be used equally.

  Specific examples of the diol include diols having a molecular weight of 400 or less, for example, aliphatic diols such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, , 1-cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, alicyclic diols such as tricyclodecane dimethanol, and xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxy) diphenylpropane, 2,2′-bis [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxyethoxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane Aromatic diols such as 4,4′-dihydroxy-p-terphenyl and 4,4′-dihydroxy-p-quarterphenyl are preferred, and such diols are ester-forming derivatives such as acetyl compounds and alkali metal salts. It can also be used in the form.

  Two or more of these dicarboxylic acids, derivatives thereof, diol components and derivatives thereof may be used in combination. An example of a preferable high-melting crystalline polymer segment (a1) is a polybutylene terephthalate unit derived from terephthalic acid and / or dimethyl terephthalate and 1,4-butanediol. Also preferred are those composed of polybutylene terephthalate units derived from terephthalic acid and / or dimethyl terephthalate, and polybutylene isophthalate units derived from isophthalic acid and / or dimethyl isophthalate and 1,4-butanediol. .

  The low melting point polymer segment (a2) of the polyester elastomer (A) used in the present invention is an aliphatic polyether. Specific examples of the aliphatic polyether include poly (ethylene oxide) glycol and poly (propylene oxide) glycol. , Poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, an ethylene oxide adduct of poly (propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Of these, poly (tetramethylene oxide) glycol and / or poly (propylene oxide) glycol ethylene oxide adducts and / or copolymers of ethylene oxide and tetrahydrofuran are preferred.

  The copolymerization amount of the low-melting polymer segment (a2) of the polyester elastomer (A) used in the present invention is usually 10 to 90% by weight, preferably 15 to 75% by weight.

  The polyester elastomer (A) used in the present invention can be produced by a known method. Specific examples thereof include, for example, a method of transesterifying a lower alcohol diester of a dicarboxylic acid, an excessive amount of a low molecular weight glycol and a low melting point polymer segment component in the presence of a catalyst, and polycondensing the resulting reaction product, and Any method such as a method in which a dicarboxylic acid, an excess amount of glycol and a low melting point polymer segment component are esterified in the presence of a catalyst and the resulting reaction product is polycondensed may be used.

  The polymer (B) used in the present invention is a polymer composed of a silicone compound (b1) and an ethylene copolymer (b2). The ethylene copolymer is modified with a silicone compound. It is a silicone modified product. A preferred form is a copolymer having an ethylene copolymer unit and a silicone compound unit in the molecule, which is obtained by heating and kneading the ethylene copolymer and the silicone compound and grafting the silicone compound onto the ethylene copolymer. Can do. Particularly preferably, an ethylene copolymer and a cyclone compound are grafted by heating and kneading, and in this case, a crosslinking agent or a reaction terminator can be used. The copolymerization ratio of the silicone compound (b1) and the ethylene copolymer (b2) is 20-80% by weight of the silicone compound and 20-80% by weight of the ethylene copolymer, preferably 30-70% by weight of the silicone compound and the ethylene copolymer. The polymer is 30 to 70% by weight. When the silicone compound (b1) is less than 20% by weight and the ethylene copolymer (b2) is 80% by weight or more, the slidability as the polyester elastomer resin composition is inferior and the mechanical properties are impaired. When (b1) is 80% by weight or more and the ethylene copolymer (b2) is less than 20% by weight, the surface appearance of the molded article of the polyester elastomer resin composition is inferior.

  The polymer (B) used in the present invention is composed of the silicone compound (b1) and the ethylene copolymer (b2) as a simple substance, in addition to the polymer composed of the silicone compound (b1) and the ethylene copolymer (b2). The silicone compound (b1) alone is 0.01 to 40 parts by weight, and the ethylene copolymer (b2) alone is 0.01 per 100 parts by weight of the polymer (B). It is -40 weight part, and since it exceeds 40 weight part, since the molded article surface appearance of a polyester elastomer resin composition is impaired, it is unpreferable.

  The blending ratio of the polymer (B) comprising the polyester elastomer (A), the silicone compound (b1) and the ethylene compound (b2) of the present invention is 86 to 99.95% by weight of the polyester elastomer (A), and the polymer (B). The blending ratio of 0.05 to 14% by weight, more preferably 90 to 99.5% by weight of the polyester elastomer (A), 0.5 to 10% by weight of the polymer (B), more preferably 90 to 90% of the polyester elastomer (A). 99% by weight and 1-10% by weight of polymer (B) are recommended.

  The silicone compound (b1) of the present invention is a silicone resin such as dimethylpolysiloxane, methylphenylpolysiloxane, trifluoropropylmethylpolysiloxane, etc., and a silicone resin modified with an amino group, vinyl group, or alkylallyl group is also used. be able to.

  The ethylene copolymer (b2) used in the present invention is an ethylene acrylic acid copolymer (EAA), an ethylene methacrylic acid copolymer (EMAA), an ethylene methyl acrylate copolymer (EMA), or an ethylene ethyl acrylate. Examples thereof include a copolymer (EEA), an ethylene methyl methacrylate copolymer (EMMA), an ethylene vinyl acetate copolymer (EVA), and an ethylene vinyl alcohol copolymer (EVOH).

  There is no restriction | limiting in particular as the mixing method of the polyester elastomer resin composition of this invention, The polymer (B) which consists of a polyester elastomer (A), a silicone compound (b1), and an ethylene copolymer (b2) is mix | blended in arbitrary ratios. In addition, a heat kneading method using a Banbury mixer, an extruder, or the like can be employed. Further, the polyester elastomer (A), the silicone compound (b1) and the ethylene copolymer (b2) are kneaded together with a crosslinking agent and a reaction terminator with a Banbury mixer, an extruder or the like, so that the silicone compound (b1) and the ethylene copolymer are mixed. The polymerization of the polymer (b2) (graph and polymerization) and the polyester elastomer (A) may be mixed simultaneously. At this time, it is not necessary to complete the polymerization of the silicone compound (b1) and the ethylene copolymer (b2). As a result, the polyester elastomer (A) is 86 to 99.95% by weight, and the silicone compound (b1) The polymer (B) with the ethylene copolymer (b2) may be 0.05 to 14% by weight. In such a case, the resin composition further contains an unreacted silicone compound (b1) and an ethylene copolymer (b2).

  As a preferred method, the silicone compound (b1) and the ethylene copolymer (b2) are first heated and kneaded together with a crosslinking agent or the like to produce a polymer (B) of the silicone compound and the ethylene copolymer, and then the polyester elastomer ( A method of blending A) and kneading with heating is mentioned.

  In addition, the polyester elastomer resin composition of the present invention includes an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a lubricant, a dye, a pigment, a plasticizer, a difficult agent, and the like as long as the purpose is not impaired. Additives such as a flame retardant, a release agent, and silicone oil can be added.

  The effects of the present invention will be described below with reference to examples. In the examples, “%” and “parts” are based on weight unless otherwise specified. The physical properties shown in the examples were measured as follows.

[Hardness (Durometer D)]
Measured according to ASTM D-2240.

[Mechanical properties]
According to JIS K7113, the tensile strength at break and the tensile elongation at break were measured.

[Sliding wear test]
The amount of wear and the coefficient of dynamic friction were measured according to JIS K7218. The mating material is S45C, the test speed is 72 mm / sec, the load is 100 N, and the sliding distance is 259 m (60 min).

[Appearance of molded product surface]
The appearance of the molded product surface is visually observed to check for the presence of delamination and flow marks. The case where there was no appearance defect and the surface appearance of the molded product was good was marked with ○, and the case where the appearance defect was confirmed was marked with ×.

[Compounds used in Examples]
[Polyester elastomer (A-1)]
234 parts of terephthalic acid, 222 parts of 1,4-butanediol and 723 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 2000 are charged into a reaction vessel equipped with a helical ribbon type stirring blade together with 3 parts of titanium tetrabutoxide. The esterification reaction was performed while heating at 190 to 225 ° C. for 3 hours and distilling the reaction water out of the system. In this reaction mixture, 0.5 part of “Irganox” 1010 (a hindered phenol antioxidant manufactured by Ciba Geigy Co., Ltd.) was developed, the temperature was raised to 245 ° C., and then the pressure in the system was reduced to 27 Pa over 40 minutes. Then, polymerization was performed for 2 hours and 40 minutes under the conditions to obtain a polyester elastomer (A-1). The obtained polyester elastomer was discharged into water as a strand and cut into pellets. The hardness of this polyester elastomer was 30 Shore D.

[Polyester elastomer (A-2)]
Polymerization and cutting were carried out in the same manner as in (A-1) except that 444 parts of terephthalic acid, 386 parts of 1,4-butanediol and 439 parts of poly (tetramethylene oxide) glycol having a number average molecular weight of about 1400 were used. A polyester elastomer (A-2) was obtained. The hardness of this polyester elastomer was 50 Shore D.

[Polymer of silicone compound and ethylene copolymer (B-1)]
BY27-219 manufactured by Toray Dow Corning Co., Ltd. Silicone content 60% ethylene methyl methacrylate copolymer

[Polymer of silicone compound and ethylene copolymer (B-2)]
BY27-220 manufactured by Toray Dow Corning Co., Ltd. Silicone content 60% ethylene vinyl acetate copolymer

[Polymer of silicone compound and ethylene copolymer (B-3)]
50 parts by weight of vinyl group-containing polydimethylsiloxane (NER-2 manufactured by Shin-Etsu Chemical Co., Ltd.), 50 parts by weight of ethylene ethyl acrylate copolymer (EEA) (NUC-6570 manufactured by Nihon Unicar), and peroxide (Perbutyl manufactured by NOF Corporation) P) Polymer composition obtained by adding 0.05 parts by weight and 0.02 part by weight of an antioxidant (Irganox 1010 manufactured by Ciba Specialty Chemicals) into a Banbury mixer set at 120 ° C. and mixing for 10 minutes. The product was pelletized.

[Mixture of silicone compound and polyester elastomer (Z-1)]
BY27-010 manufactured by Toray Dow Corning Co., Ltd. Mixture of polyester elastomer and silicone compound (silicone content 50%)

[Silicone compound (b1)]
Vinyl group-containing polydimethylsiloxane (NER-2 manufactured by Shin-Etsu Chemical)

[Ethylene copolymer (b2)]
Ethylene ethyl acrylate copolymer (EEA) (NUC-6570 manufactured by Nihon Unicar)

[Examples 1 to 10, Comparative Examples 1 to 11]
Polyester elastomers (A-1), (A-2), silicone-modified silicone copolymers (B-1), (B-2), (B-3), a mixture of a silicone compound and a polyester elastomer ( Z-1), a silicone compound (b1), and an ethylene copolymer (b2) are mixed using a V-blender at a blending ratio (% by weight) shown in Tables 1 and 2, and a three-thread type with a diameter of 45 mm. Was pelletized using a twin-screw extruder having a screw. The heating temperature was 200.degree. C. for polyester elastomer (A-1) and 230.degree. C. for polyester elastomer (A-2).

  After drying the obtained pellet at 80 ° C. for 5 hours, the polyester elastomer resin composition using the polyester elastomer (A-1) is 190 ° C., and the polyester elastomer resin composition using the polyester elastomer (A-2) is 230 ° C. JIS No. 2 dumbbell test piece and 120 mm long x 70 mm wide x 2 mm thick square plate molded products were injection molded at a mold temperature of 30 ° C (mold cavity surface) using an in-line screw injection molding machine set to . The hardness was tested using a square plate molded product, and the tensile test using a JIS No. 2 dumbbell test. For the wear resistance, a molded product obtained by punching a disk of φ50 mm from a square plate molded product was used. For observation of the surface appearance of the molded product, a JIS No. 2 test piece and a square plate molded product were used. The results of examining the characteristics are shown in Tables 1 and 2.

[Example 11]
Polyester elastomer (A-1) 95 wt%, silicone compound (b1) 2.5 wt%, ethylene copolymer (b2) 2.5 wt%, peroxide (Nippon Yushi Fatty Perbutyl P) 0.05 wt%, antioxidant 0.02 wt% of an agent (Ciba Specialty Chemicals Irganox 1010) was mixed using a V-blender and melt kneaded using a twin screw extruder set at 190 ° C having a diameter of 45 mm and a triple thread type screw. A polyester elastomer resin composition was obtained and pelletized. The ratios of the polymer comprising the silicone compound and the ethylene copolymer, the silicone compound alone, and the ethylene copolymer alone in the polyester elastomer resin composition were 54%, 23%, and 23%, respectively. The obtained pellets were molded and evaluated in the same manner as in Examples 1-10. The results of examining the characteristics are shown in Table 1.

  From the above results, the polyester elastomer resin compositions of the present invention shown in Examples 1 to 11 showed excellent mechanical properties, and the wear resistance was small and the friction coefficient was low. Furthermore, the observation of the surface appearance of the molded product was good because no delamination or flow marks were observed. In Comparative Examples 1 and 2, since no silicone compound is contained, the wear resistance is insufficient, and in Comparative Examples 3 to 6 containing a large amount of silicone compound, the mechanical properties are inferior. In Comparative Examples 7 to 10 not containing an ethylene copolymer, delamination and flow marks were observed on the surface appearance of the molded product, and a good surface appearance was not obtained. In Comparative Example 11 containing the silicone compound and the ethylene copolymer alone, delamination was observed on the surface appearance of the molded product, and a good surface appearance was not obtained.

  The polyester elastomer resin composition of the present invention is useful for automobiles, electronic / electric equipment, precision equipment, and various molded articles for general consumer goods, taking advantage of the above-described excellent characteristics, and particularly excellent wear resistance. It is suitable for applications that achieve both a molded product surface appearance.

Claims (4)

The main component is a high-melting-point crystalline polymer segment (a1) mainly composed of a crystalline aromatic polyester unit and a low-melting-point polymer segment (a2) mainly composed of an aliphatic polyether unit and / or an aliphatic polyester unit. A polyester elastomer resin composition comprising 86 to 99.95% by weight of the polyester elastomer (A) and 0.05 to 14% by weight of the polymer (B) comprising the silicone compound (b1) and the ethylene copolymer (b2). The polyester elastomer resin composition according to claim 1, wherein the low-melting polymer segment (a2) of the polyester elastomer (A) has a copolymerization amount of 10 to 90% by weight. 3. The polyester elastomer resin composition according to claim 1, wherein the polymer (B) is a graft copolymer of 20 to 80% by weight of a silicone compound and 20 to 80% by weight of an ethylene copolymer. Furthermore, 0.01 to 40 parts by weight of the silicone compound (b1) alone and 0.01 to 40 parts by weight of the ethylene copolymer (b2) alone are contained with respect to 100 parts by weight of the polymer (B). The polyester elastomer resin composition according to any one of claims 1 to 3.