JP2023127056A - Thermoplastic elastomer resin composition - Google Patents

Abstract

To provide a thermoplastic elastomer resin composition, which, in uses such as automobiles, electric machines and industrial applications, has flexible and excellent mechanical characteristics, good low temperature characteristics, moldability, and excellent flowability.SOLUTION: A thermoplastic elastomer resin composition comprises: 55-99 pts.wt. of a polyester block copolymer (A) comprising a high melting point crystalline polymer segment (a1) composed of crystalline aromatic polyester units and a low melting point polymer segment (a2) composed of aliphatic polyether units; and 1-45 pts.wt. of a wholly aromatic liquid crystal polyester resin (B), relative to 100 pts.wt. of the thermoplastic elastomer resin composition, where the wholly aromatic liquid crystal polyester resin (B) has a melting point of 240°C or less.SELECTED DRAWING: None

Description

The present invention relates to a thermoplastic elastomer composition that has high resin strength, excellent moldability, particularly good flexibility at low temperatures, and excellent fluidity.

Polyesters having crystalline aromatic polyester units as high melting point crystalline polymer segments and aliphatic polyether units such as poly(alkylene oxide) glycol and/or aliphatic polyester units such as polylactones as low melting point polymer segments. Block copolymers have excellent mechanical properties such as resin strength, impact resistance, elastic recovery, flexibility, and bending fatigue resistance, as well as low-temperature and high-temperature properties, and are thermoplastic and easy to mold. Widely used in automobile parts and industrial materials.

In recent years, with the electrification of automobiles and the development of the information technology field, the use of resin materials for small electronic parts and the like has been considered. In such cases, the parts are manufactured by injection molding, but if the fluidity of the resin material is low, there is a problem that the resin material does not reach the end of the part during injection molding, making it impossible to obtain a clean molded product. Furthermore, there is a concern that molded products may deteriorate due to heat when molded at high temperatures to increase fluidity.

As a method for improving the fluidity of a polyester block copolymer, a polyester elastomer resin composition to which a polyester random copolymer is added (for example, see Patent Document 1) has been proposed.

Patent No. 5567299

However, the composition of Patent Document 1 has a problem in that although the fluidity is improved, the resin strength is reduced. Further, such parts are used in a wide temperature range from low temperatures to high temperatures. Therefore, it is required to have flexibility over a wide temperature range.

The present invention was achieved as a result of studies to solve the above-mentioned problems of the prior art, and has high resin strength, excellent moldability, particularly good flexibility at low temperatures, and fluidity. It is an object of the present invention to provide a thermoplastic elastomer resin composition that has excellent properties.

In order to solve the above problems, the present invention employs the following means. That is, the present invention provides a high melting point crystalline polymer segment (a1) consisting of a crystalline aromatic polyester unit and a low melting point polymer segment (a1) consisting of an aliphatic polyether unit based on 100 parts by weight of a thermoplastic elastomer resin composition. a2) and 55 to 99 parts by weight of a polyester block copolymer (A) containing 1 to 45 parts by weight of a wholly aromatic liquid crystal polyester resin (B), ) has a melting point of 240°C or less.

According to the present invention, as explained below, it is possible to obtain a thermoplastic elastomer composition that has high resin strength, excellent moldability, particularly good flexibility at low temperatures, and excellent fluidity. .

The present invention will be described below. The thermoplastic elastomer resin composition of the present invention comprises as constituent components a high melting point crystalline polymer segment (a1) consisting of crystalline aromatic polyester units and a low melting point polymer segment (a2) consisting of aliphatic polyether units. Contains a polyester block copolymer (A).

The polyester block copolymer (A) used in the present invention comprises a high melting point crystalline polymer segment (a1) consisting of crystalline aromatic polyester units and a low melting point polymer segment (a2) consisting of aliphatic polyether units. The high melting point crystalline polymer segment is mainly composed of crystalline aromatic polyester units, that is, mainly aromatic dicarboxylic acid or its ester-forming derivative, and diol or It is a polyester formed from its ester-forming derivative.

Examples of the aromatic dicarboxylic acid or its ester-forming derivative include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, anthracenedicarboxylic acid, and diphenyl-4,4-dicarboxylic acid. -dicarboxylic acid, diphenoxyethane dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 5-sulfoisophthalic acid, and sodium 3-sulfoisophthalate. In the present invention, the aromatic dicarboxylic acid is mainly used, but a part of the aromatic dicarboxylic acid is replaced with alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, cyclopentanedicarboxylic acid, and 4,4'-dicyclohexyldicarboxylic acid. It may be substituted with aliphatic dicarboxylic acids such as group dicarboxylic acids, adipic acid, succinic acid, oxalic acid, sebacic acid, dodecanedioic acid, and dimer acid. Furthermore, ester-forming derivatives of dicarboxylic acids, such as lower alkyl esters, aryl esters, carbonic esters, and acid halides, can of course be used equally well.

The aromatic dicarboxylic acid or its ester-forming derivative as the dicarboxylic acid component is preferably terephthalic acid, dimethyl terephthalate, isophthalic acid, or dimethyl isophthalate.

The diols or their ester-forming derivatives include diols with a molecular weight of 400 or less, such as fats such as 1,4-butanediol, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and decamethylene glycol. alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-dicyclohexanedimethanol, 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, 4,4'-dihydroxy-p-terphenyl, and 4,4'-dihydroxy-p-quarterphenyl, and such diols are preferred, and such diols can be combined with ester-forming derivatives such as acetyl derivatives, It can also be used in the form of an alkali metal salt.

Two or more of these dicarboxylic acids, derivatives thereof, diol components, and derivatives thereof may be used in combination.

Such high melting point crystalline polymer segment (a1) comprises polybutylene terephthalate units derived from terephthalic acid or dimethyl terephthalate and 1,4-butanediol and/or polybutylene terephthalate units derived from isophthalic acid or dimethyl isophthalate and 1,4-butanediol. Those whose main constituent is derived polybutylene isophthalate units are preferably used.

The amount of copolymerization of the high melting point crystalline polymer segment (a1) is preferably 20 to 90% by weight, more preferably 30 to 70% by weight, even more preferably 40 to 70% by weight.

The copolymerization amount of the high melting point crystalline polymer segment (a1) is, for example, when the constituent component of the high melting point crystalline polymer segment (a1) is a polybutylene terephthalate unit, the amount of copolymerization of terephthalic acid, 1,4-butanediol, It is the sum of each mass%.

The low melting point polymer segment (a2) used in the polyester block copolymer (A) used in the present invention mainly consists of aliphatic polyether.

Specific examples of such aliphatic polyethers include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(trimethylene oxide) glycol, poly(tetramethylene oxide) glycol, poly(hexamethylene oxide) glycol, and ethylene oxide. Examples include copolymers of propylene oxide, ethylene oxide adducts of poly(propylene oxide) glycol, and copolymers of ethylene oxide and tetrahydrofuran. Among these, ethylene oxide adducts of poly(tetramethylene oxide) glycol and/or poly(propylene oxide) glycol and/or copolymers of ethylene oxide and tetrahydrofuran are preferably used. Particularly preferred are those containing poly(tetramethylene oxide) glycol units as a main component.

The amount of copolymerization of the low melting point polymer segment (a2) of the polyester block copolymer (A) used in the present invention is preferably 10 to 80% by weight, more preferably 30 to 70% by weight, even more preferably is 30 to 60% by weight. Especially when the amount of copolymerization of the low melting point polymer segment (a2) is large, the low temperature properties are particularly excellent.

The copolymerization amount of the low melting point crystalline polymer segment (a2) is, for example, when the constituent component of the low melting point crystalline polymer segment (a2) is a poly(tetramethylene oxide) glycol unit. % by mass.

The polyester block copolymer (A) used in the present invention can be produced by a known method. Specific examples thereof include, for example, a method in which a lower alcohol diester of a dicarboxylic acid, an excess amount of low molecular weight glycol, and a low melting point polymer segment component are transesterified in the presence of a catalyst, and the resulting reaction product is subjected to melt polycondensation; Alternatively, any method may be used, such as carrying out an esterification reaction with the dicarboxylic acid, an excess amount of glycol, and a low melting point polymer segment component in the presence of a catalyst, and subjecting the resulting reaction product to melt polycondensation.

The polyester block copolymer (A) obtained by polycondensation may then be subjected to solid phase polycondensation. Solid phase polycondensation is carried out at a temperature at which the polyester block copolymer (A) pelletized after melt polycondensation does not fuse, and is usually carried out at a temperature in the range of 140°C to 220°C. It is desirable to undergo preliminary crystallization and drying steps before solid phase polycondensation. Solid phase polycondensation is also carried out under high vacuum or inert gas flow. In the case of high vacuum, it is preferably carried out under reduced pressure of 665 Pa or less, more preferably 133 Pa or less. In the case of an inert gas stream, it is typically preferable to carry out the reaction under a nitrogen stream, and the pressure is not particularly limited, but atmospheric pressure is preferable. As the reaction vessel, it is preferable to use a rotatable vacuum dryer, a tower dryer through which an inert gas can flow, or the like.

The thermoplastic elastomer resin composition of the present invention is characterized by containing a wholly aromatic liquid crystal polyester resin (B). The wholly aromatic liquid crystal polyester resin (B) used in the present invention is a polyester resin whose repeating units are all aromatic compounds, and is called a thermotropic liquid crystal polyester resin in the technical field. be.

Further, the wholly aromatic liquid crystal polyester resin (B) used in the present invention is characterized in that the melting point is 240°C or lower. More preferably, the temperature is 170°C or higher and 230°C or lower. When the temperature exceeds 240°C, the productivity of the thermoplastic elastomer resin composition decreases.

The blending amount of the polyester block copolymer (A) and the wholly aromatic liquid crystal polyester resin (B) is 55 to 99 parts by weight of the polyester block copolymer (A) to 100 parts by weight of the thermoplastic elastomer resin composition. It contains 1 to 45 parts by weight of aromatic liquid crystal polyester resin (B). In the thermoplastic elastomer resin composition of the present invention, resins other than the polyester block copolymer (A) and the wholly aromatic liquid crystalline polyester resin (B) may be used as resin components as necessary within a range that does not impair the purpose of the present invention. However, it is preferable that the thermoplastic elastomer resin composition of the present invention contains only the polyester block copolymer (A) and the wholly aromatic liquid crystalline polyester resin (B) as resin components.

In addition, the thermoplastic elastomer resin composition of the present invention may contain antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, lubricants, dyes, pigments, Additives such as plasticizers, flame retardants, mold release agents, and silicone oil can be added.

The method for producing the thermoplastic elastomer resin composition of the present invention is not particularly limited. A method of supplying the material to a machine and melting and kneading it, etc. can be adopted as appropriate.

The thermoplastic elastomer resin composition of the present invention is made into a molded article by injection molding, blow molding, extrusion molding, compression molding, or the like.

The effects of the present invention will be explained below with reference to Examples. The present invention can be implemented with appropriate modifications within the scope of the gist of the invention. Note that all percentages and parts in the examples are based on weight unless otherwise specified. Moreover, the physical properties shown in the examples were measured by the following measuring method.

[Melting point]
Using TA Instruments DSC Q100, heat from 40°C to 250°C at a temperature increase rate of 20°C/min in a nitrogen atmosphere, hold at 250°C for 3 minutes, and then increase the temperature at 10°C/min. The temperature at the top of the melting peak was measured when the sample was cooled to 40° C. at a temperature decreasing rate and further heated to 250° C. at a temperature increasing rate of 10° C./min.

[Hardness (Durometer D)]
The hardness was measured using ASKER CL-150 manufactured by Kobunshi Keiki Co., Ltd. according to JIS K7215 durometer D hardness.

[Tensile strength at break, tensile elongation at break, tensile modulus]
Pellets dried with hot air at 90°C for 3 hours or more were molded into JISK7113 No. 2 dumbbell test pieces using an injection molding machine (NEX-1000 manufactured by Nissei Plastics Co., Ltd.) under molding conditions of a cylinder temperature of 240°C and a mold temperature of 50°C. It was molded and measured at 23° C. according to JIS K7113 (1995 edition).

[Melt viscosity measurement]
Using Capillograph C1 manufactured by Toyo Seiki Seisakusho, the relationship between shear rate and melt viscosity was measured under the conditions of a measurement temperature of 230°C, an orifice length of 10 mm, and an orifice diameter of 1.0 mm, and the melt viscosity at a shear rate of 600/sec was determined. I read it.

[Bending elastic modulus]
Using a test piece made from pellets dried with hot air at 90°C for 3 hours or more using an injection molding machine (NEX-1000 manufactured by Nissei Plastics Co., Ltd.) under molding conditions of a cylinder temperature of 240°C and a mold temperature of 50°C, Measurements were made in accordance with ASTM D790 at 23°C and -30°C.

[Manufacture of polyester elastomer (A-1)]
350 parts of terephthalic acid and 150 parts of 1,4-butanediol as the high melting point crystalline polymer segment (a1), and 354 parts of poly(tetramethylene oxide) glycol having a number average molecular weight of about 1400 as the low melting point polymer segment (a2). was charged into a reaction vessel equipped with a helical ribbon stirring blade along with 0.3 parts of titanium tetrabutoxide and 0.2 parts of mono-n-butyl-monohydroxytin oxide, and heated at 190 to 225°C for 3 hours to dissolve the reaction water. The esterification reaction was carried out while distilling out of the system. After adding 2.0 parts of titanium tetrabutoxide and 0.5 parts of "Irganox" 1098 (hindered phenolic antioxidant manufactured by Ciba Geigy) to the reaction mixture, the temperature was raised to 245°C, and then the temperature was increased to 50°C. The pressure in the system was reduced to 0.2 mmHg over several minutes, and melt polycondensation was carried out under these conditions for 2 hours and 45 minutes. The obtained polyester elastomer was discharged in the form of a strand into water and cut into pellets.

The weight % of the high melting point crystalline polymer segment (a1) was 37, and the weight % of the low melting point polymer segment (a2) was 63.

[Manufacture of polyester elastomer (A-2)]
420 parts of terephthalic acid and 196 parts of 1,4-butanediol as the high melting point crystalline polymer segment (a1), and 480 parts of poly(tetramethylene oxide) glycol having a number average molecular weight of about 1400 as the low melting point polymer segment (a2). was charged into a reaction vessel equipped with a helical ribbon stirring blade along with 0.3 parts of titanium tetrabutoxide and 0.2 parts of mono-n-butyl-monohydroxytin oxide, and heated at 190 to 225°C for 3 hours to dissolve the reaction water. The esterification reaction was carried out while distilling out of the system. After adding 2.0 parts of titanium tetrabutoxide and 0.5 parts of "Irganox" 1098 (hindered phenolic antioxidant manufactured by Ciba Geigy) to the reaction mixture, the temperature was raised to 245°C, and then the temperature was increased to 50°C. The pressure in the system was reduced to 0.2 mmHg over several minutes, and melt polycondensation was carried out under these conditions for 2 hours and 45 minutes. The obtained polyester elastomer was discharged in the form of a strand into water and cut into pellets.

The weight % of the high melting point crystalline polymer segment (a1) was 52, and the weight % of the low melting point polymer segment (a2) was 48.

[Manufacture of polyester elastomer (A-3)]
505 parts of terephthalic acid and 251 parts of 1,4-butanediol as the high melting point crystalline polymer segment (a1), and 229 parts of poly(tetramethylene oxide) glycol with a number average molecular weight of about 1400 as the low melting point polymer segment (a2). was charged into a reaction vessel equipped with a helical ribbon stirring blade along with 0.3 parts of titanium tetrabutoxide and 0.2 parts of mono-n-butyl-monohydroxytin oxide, and heated at 190 to 225°C for 3 hours to dissolve the reaction water. The esterification reaction was carried out while distilling out of the system. After adding 2.0 parts of titanium tetrabutoxide and 0.5 parts of "Irganox" 1098 (hindered phenolic antioxidant manufactured by Ciba Geigy) to the reaction mixture, the temperature was raised to 245°C, and then the temperature was increased to 50°C. The pressure in the system was reduced to 0.2 mmHg over several minutes, and melt polycondensation was carried out under these conditions for 2 hours and 45 minutes. The obtained polyester elastomer (A-3) was discharged into water in the form of a strand and cut into pellets. The weight % of the high melting point crystalline polymer segment (a1) was 65, and the weight % of the low melting point polymer segment (a2) was 35.

[Wholly aromatic liquid crystal polyester resin (B)]
As a wholly aromatic liquid crystal polyester resin (B),
(B-1): AL-7000 manufactured by Ueno Pharmaceutical Co., Ltd. (melting point 180°C)
(B-2): A-8100 manufactured by Ueno Pharmaceutical Co., Ltd. (melting point 220°C)
It was used.

[Examples 1 to 5]
Using a twin-screw extruder having a screw with a diameter of 45 mm, the polyester elastomers (A-1) and (A-2) shown in Reference Examples and the wholly aromatic liquid crystal polyester resin (B) were prepared with the compounding composition shown in Table 1. and added from the initial charging section. Melt mixing was performed under extrusion conditions of a heating temperature of 240° C. and a screw rotation of 150 rpm, and the mixture was discharged in the form of a strand, passed through a cooling bath, and pelletized using a strand cutter to obtain a thermoplastic elastomer resin composition.

The obtained pellets were dried at 90°C for 3 hours and then injection molded under conditions of a cylinder temperature of 240°C and a mold temperature of 50°C to obtain test pieces for tensile strength at break, tensile elongation at break, and tensile modulus test. Ta. Various tests were conducted using the obtained test pieces.

[Comparative Examples 1 to 3]
Using a twin-screw extruder having a screw with a diameter of 45 mm, the polyester elastomers (A-1), (A-2), and (A-3) shown in Reference Examples were mixed in the composition shown in Table 1, It was added from the initial charging section. Melt mixing was performed under extrusion conditions of a heating temperature of 240° C. and a screw rotation of 150 rpm, and the mixture was discharged in the form of a strand, passed through a cooling bath, and pelletized with a strand cutter to obtain a thermoplastic polyester elastomer resin composition.

The obtained pellets were dried at 90°C for 3 hours and then injection molded under conditions of a cylinder temperature of 240°C and a mold temperature of 50°C to obtain test pieces for tensile strength at break, tensile elongation at break, and tensile modulus test. Ta. Various tests were conducted using the obtained test pieces.

As is clear from the results in Table 1, the thermoplastic elastomer resin composition of the present invention in which the wholly aromatic liquid crystal polyester resin (B) was blended with the polyester elastomer (A) shown in Examples 1 to 5, Excellent strength and tensile elongation at break. Furthermore, compared to the elastic modulus at 23° C., the increase in the elastic modulus at low temperatures (-30° C.) is small, and the material has excellent flexibility.

For example, Examples 1 and 2 using the polyester block copolymer (A-1) have a smaller ratio of flexural modulus at 23° C. and -30° C. than Comparative Example 1, and change in physical properties at low temperatures is small.

The same applies to Example 3 and Comparative Example 2 in which the polyester block copolymer (A-2) was used. Example 4 and Comparative Example 2 have the same flexural modulus at 23°C, but Example 4 has a much smaller flexural modulus at -30°C than Comparative Example 3, and maintains its flexibility at low temperatures.

Furthermore, the melt viscosity measured at 230° C. was low at a shear rate of 600/sec.

The resin compositions of Comparative Examples 1 to 3 in which the wholly aromatic liquid crystalline polyester resin (B) is not blended have poor flexibility or high melt viscosity at low temperatures compared to the thermoplastic elastomer resin composition of the present invention.

The thermoplastic elastomer resin composition of the present invention not only has sufficient strength and rigidity as described above, but also has excellent fluidity, so it is particularly suitable for small molded products such as automobile parts, electrical equipment, and industrial products. It is easily obtained and suitable for products that require flexibility at low temperatures.

Claims (4)

A high melting point crystalline polymer segment (a1) consisting of a crystalline aromatic polyester unit and a low melting point polymer segment (a2) consisting of an aliphatic polyether unit are added to 100 parts by weight of the thermoplastic elastomer resin composition as constituent components. 55 to 99 parts by weight of a polyester block copolymer (A) and 1 to 45 parts by weight of a wholly aromatic liquid crystal polyester resin (B), and the melting point of the wholly aromatic liquid crystal polyester resin (B) is 240°C. A thermoplastic elastomer resin composition characterized by: Claim 1 characterized in that the high melting point crystalline polymer segment (a1) in the polyester block copolymer (A) contains polybutylene terephthalate units and/or polybutylene isophthalate units as a main component. The thermoplastic elastomer resin composition described. 3. The thermoplastic resin according to claim 1 or 2, wherein the low melting point polymer segment (a2) in the polyester block copolymer (A) has a poly(tetramethylene oxide) glycol unit as a main component. Plastic elastomer resin composition. The thermoplastic elastomer resin according to any one of claims 1 to 3, wherein the copolymerized amount of the low melting point polymer segment (a2) in the polyester block copolymer (A) component is 10 to 80% by weight. Composition.