WO2022080354A1

WO2022080354A1 - Thermoplastic polyester elastomer resin composition and method for producing same

Info

Publication number: WO2022080354A1
Application number: PCT/JP2021/037681
Authority: WO
Inventors: 恵梨森尾; 卓也赤石
Original assignee: 東洋紡株式会社
Priority date: 2020-10-15
Filing date: 2021-10-12
Publication date: 2022-04-21
Also published as: JPWO2022080354A1

Abstract

The present invention provides a thermoplastic polyester elastomer resin composition which is lightweight and has excellent surface characteristics, fatigue characteristics and wear characteristics. This thermoplastic polyester elastomer resin composition contains from 0.1 part by mass to 30 parts by mass of (B) cellulose fibers relative to 100 parts by mass of (A) a thermoplastic polyester elastomer wherein a hard segment, which is composed of a polyester that comprises an aromatic dicarboxylic acid and an aliphatic and/or alicyclic diol as constituents, and at least one soft segment, which is selected from among an aliphatic polyether, an aliphatic polyester and an aliphatic polycarbonate, are bonded with each other; and the cellulose fibers (B) in this resin composition have an average fiber length of from 100 μm to 2,000 μm, while having an average fiber diameter of from 0.5 μm to 50 μm.

Description

Thermoplastic polyester elastomer resin composition and its manufacturing method

The present invention relates to a thermoplastic polyester elastomer resin composition having excellent mechanical properties, fatigue properties, wear properties, and surface properties while maintaining the performance as an elastomer.

Thermoplastic polyester elastomer is excellent in injection moldability and extrusion moldability, has high mechanical strength, has rubber properties such as elastic recovery, impact resistance, and flexibility, and is a material with excellent cold resistance. It is used in applications such as electronic parts, textiles, films, and sports parts.

However, the thermoplastic polyester elastomer alone may have insufficient surface properties, fatigue properties, etc., and a composite of the elastomer and various inorganic materials is used. On the other hand, a resin composition in which a thermoplastic elastomer is reinforced with an inorganic filler such as glass fiber, carbon fiber, talc, or clay has a high specific gravity or the filler itself becomes a defect, which deteriorates the performance as an elastomer. There is a problem.

In recent years, cellulose has been attracting attention as a new reinforcing material for resins. Cellulose is known to have a high elastic modulus and a low coefficient of linear expansion as its elemental properties, and due to its excellent properties, high functionality of the resin can be expected even with a small amount of addition. In addition, the true density is 1.6 g / cm ³ , which is lower than that of glass fiber (density 2.3 to 2.6 g / cm ³ ) and talc (density 2.7 g / cm ³ ), and is suitable for weight reduction. It is a material.

For example, Patent Document 1 proposes modified nanocellulose in which a hydroxyl group in nanocellulose is substituted with a specific substituent, and a resin composition containing this and a resin is proposed. In the above document, a resin composition showing high tensile strength and elastic modulus can be obtained, but surface characteristics and fatigue characteristics are not mentioned.

Further, Patent Document 2 describes that when the cellulose raw material is kneaded in the presence of a resin solution while removing the solvent by heating, the cellulose nanofibers having a high content can be uniformly dispersed in the resin. Similar to Document 1, the reference is limited to mechanical properties.

Patent Document 3 describes a resin composition having excellent moldability and mechanical properties by combining cellulose fibers having different ratios of fiber diameter to fiber length. However, the cellulose properties themselves in the resin composition are resins. No mention is made of its effect on the properties of the composition.

Further, although all of Patent Documents 1 to 3 refer to the improvement of the dispersibility of cellulose and the improvement of the physical properties of general thermoplastic resins, suitable cellulose properties, surface properties, and fatigue in the elastomer resin composition are mentioned. No mention is made of its effect on the properties.

Japanese Patent No. 6120590 Japanese Patent No. 6648371 Japanese Patent No. 6419276

The present invention has been made in view of the current state of the prior art, and an object of the present invention is to provide a thermoplastic polyester elastomer resin composition which is lightweight and has excellent surface characteristics, fatigue characteristics and wear characteristics, and a molded product made of the same. There is something in it.

The present inventor has diligently studied the formulation of the thermoplastic polyester elastomer and the cellulose fiber in order to achieve the above object. As a result, the characteristics of the elastomer can be improved by containing a specific amount of cellulose fibers with respect to the thermoplastic polyester elastomer and controlling the average fiber length and average fiber diameter of the cellulose fibers in the resin composition within a specific range. It has been found that excellent surface characteristics, fatigue characteristics and wear characteristics can be obtained while retaining the properties.

That is, the present invention constitutes the following [1] to [5].
[1] A hard segment made of a polyester composed of an aromatic dicarboxylic acid and an aliphatic and / or alicyclic diol, and at least one selected from an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate. It is a thermoplastic polyester elastomer resin composition containing 0.1 to 30 parts by mass of cellulose fibers (B) with respect to 100 parts by mass of the thermoplastic polyester elastomer (A) to which soft segments are bonded, and cellulose in the resin composition. The fiber (B) is a thermoplastic polyester elastomer resin composition having an average fiber length of 100 to 2000 μm and an average fiber diameter of 0.5 to 50 μm.
[2] The content of the cellulose fiber (B) is 1 to 10 parts by mass, the average fiber length of the cellulose fiber in the resin composition is 100 to 800 μm, and the average fiber diameter is 1 to 30 μm [1]. The thermoplastic polyester elastomer resin composition according to the above.
[3] The thermoplastic polyester elastomer resin composition according to [1] or [2], which is a cellulose fiber in which the cellulose fiber (B) is modified.
[4] The thermoplastic polyester elastomer resin composition according to any one of [1] to [3], which further contains a dispersant (C).
[5] The thermoplastic polyester elastomer resin composition according to any one of [1] to [4], wherein the tensile elongation measured according to JIS K6251 of the resin composition is 300% or more.
[6] The thermoplastic polyester elastomer according to any one of [1] to [5], wherein the cellulose fiber (B) is dispersed in the thermoplastic polyester elastomer (A) using a twin-screw kneader. A method for producing a resin composition.
[7] A molded product made of the thermoplastic polyester elastomer resin composition according to any one of [1] to [5].

The thermoplastic polyester elastomer resin composition of the present invention and a molded product made of the same can exhibit lightweight and excellent surface characteristics, fatigue characteristics and wear characteristics. Furthermore, by uniformly dispersing the cellulose fibers, excellent performance can be exhibited even with a small amount of addition, and the moldability is also excellent.

A is an optical micrograph of the press sheet in Example 2, and B is an optical micrograph of the press sheet in Comparative Example 3.

[Thermoplastic Polyester Elastomer (A)]
The thermoplastic polyester elastomer (A) used in the present invention is formed by bonding a hard segment and a soft segment. The hard segment consists of polyester. As the aromatic dicarboxylic acid constituting the hard segment polyester, an ordinary aromatic dicarboxylic acid is widely used and is not particularly limited, but the main aromatic dicarboxylic acid is terephthalic acid or naphthalenedicarboxylic acid (among isomers). 2,6-naphthalenedicarboxylic acid is preferable). The content of these aromatic dicarboxylic acids is preferably 70 mol% or more, more preferably 80 mol% or more, based on the total dicarboxylic acids constituting the polyester of the hard segment. Examples of other dicarboxylic acid components include aromatic dicarboxylic acids such as diphenyldicarboxylic acid, isophthalic acid, and 5-sodium sulfoisophthalic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and tetrahydrohydride phthalic acid, succinic acid, and glutaric acid. Examples thereof include aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid and hydrogenated dimer acid. These can be used within a range that does not significantly lower the melting point of the resin, and the amount thereof is 30 mol% or less, preferably 20 mol% or less of the total acid component.

Further, in the thermoplastic polyester elastomer (A) used in the present invention, as the aliphatic or alicyclic diol constituting the polyester of the hard segment, a general aliphatic or alicyclic diol is widely used and is not particularly limited. However, it is desirable that it is mainly an alkylene glycol having 2 to 8 carbon atoms. Specific examples thereof include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol. Among these, ethylene glycol or 1,4-butanediol is preferable.

The components constituting the above-mentioned hard segment polyester include butylene terephthalate unit (unit consisting of terephthalic acid and 1,4-butanediol) or butylene naphthalate unit (2,6-naphthalenedicarboxylic acid and 1,4-butanediol). A unit consisting of (a unit consisting of) is preferable from the viewpoint of physical properties, moldability, and cost performance.

Further, when an aromatic polyester suitable as a polyester constituting a hard segment in the thermoplastic polyester elastomer (A) used in the present invention is produced in advance and then copolymerized with a soft segment component, the aromatic polyester is usually used. It can be easily obtained according to the polyester manufacturing method of. Further, it is desirable that the polyester has a number average molecular weight of 10,000 to 40,000.

The soft segment of the thermoplastic polyester elastomer (A) used in the present invention is at least one selected from aliphatic polyethers, aliphatic polyesters, and aliphatic polycarbonates.

Examples of the aliphatic polyether include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, poly (trimethylethylene oxide) glycol, and both ethylene oxide and propylene oxide. Examples thereof include a polymer, an ethylene oxide adduct of poly (propylene oxide) glycol, and a copolymer of ethylene oxide and tetrahydrofuran. Among these, ethylene oxide adducts of poly (tetramethylene oxide) glycol and poly (propylene oxide) glycol are preferable from the viewpoint of elastic properties.

Examples of the aliphatic polyester include poly (ε-caprolactone), polyenant lactone, polycaprilolactone, and polybutylene adipate. Among these, poly (ε-caprolactone) and polybutylene adipate are preferable from the viewpoint of elastic properties.

The aliphatic polycarbonate is preferably composed mainly of aliphatic diol residues having 2 to 12 carbon atoms. Examples of these aliphatic diols include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 2, 2-Diol-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-diol-1,5-pentanediol, 1,9-nonanediol, 2-methyl-1,8- Examples include octanediol. In particular, an aliphatic diol having 5 to 12 carbon atoms is preferable from the viewpoint of the flexibility and low temperature characteristics of the obtained thermoplastic polyester elastomer. These components may be used alone or in combination of two or more, if necessary, based on the cases described below.

As the aliphatic polycarbonate diol having good low temperature characteristics, which constitutes the soft segment of the thermoplastic polyester elastomer (A) used in the present invention, one having a low melting point (for example, 70 ° C. or lower) and a low glass transition temperature is used. preferable. Generally, an aliphatic polycarbonate diol composed of 1,6-hexanediol used for forming a soft segment of a thermoplastic polyester elastomer has a low glass transition temperature of about -60 ° C and a melting point of about 50 ° C. Good low temperature characteristics. In addition, the aliphatic polycarbonate diol obtained by copolymerizing the above aliphatic polycarbonate diol with an appropriate amount of, for example, 3-methyl-1,5-pentanediol has a glass transition point with respect to the original aliphatic polycarbonate diol. However, since the melting point is lowered or becomes amorphous, it corresponds to an aliphatic polycarbonate diol having good low temperature characteristics. Further, for example, the aliphatic polycarbonate diol composed of 1,9-nonane diol and 2-methyl-1,8-octane diol has a melting point of about 30 ° C. and a glass transition temperature of about −70 ° C., which are sufficiently low. , Corresponds to an aliphatic polycarbonate diol having good low temperature characteristics.

Aliphatic polyether is preferable as the soft segment of the thermoplastic polyester elastomer (A) used in the present invention.

The thermoplastic polyester elastomer (A) used in the present invention is preferably a copolymer containing terephthalic acid, 1,4-butanediol, and poly (tetramethylene oxide) glycol as main components. Among the dicarboxylic acid components constituting the thermoplastic polyester elastomer (A), terephthalic acid is preferably 40 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more. It is particularly preferably 90 mol% or more. Among the glycol components constituting the thermoplastic polyester elastomer (A), the total of 1,4-butanediol and poly (tetramethylene oxide) glycol is preferably 40 mol% or more, more preferably 70 mol% or more. It is more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

The number average molecular weight of the poly (tetramethylene oxide) glycol is preferably 500 to 4000. If the number average molecular weight is less than 500, it may be difficult to develop elastomeric properties. On the other hand, when the number average molecular weight exceeds 4000, the compatibility with the hard segment component is lowered, and it may be difficult to copolymerize in a block shape. The number average molecular weight of the poly (tetramethylene oxide) glycol is more preferably 800 or more and 3000 or less, and further preferably 1000 or more and 2500 or less.

The thermoplastic polyester elastomer (A) used in the present invention can be produced by a known method. For example, a method of transesterifying a lower alcohol diester of a dicarboxylic acid, an excess amount of low molecular weight glycol, and a soft segment component in the presence of a catalyst to polycondensate the resulting reaction product, a dicarboxylic acid and an excess amount of glycol and soft. A method in which the segment components are esterified in the presence of a catalyst and the obtained reaction product is polycondensed. A hard segment polyester is prepared in advance, and the soft segment component is added to the polyester to be randomized by a transesterification reaction. Any method may be used, such as a method of connecting the hard segment and the soft segment with a chain binder, and a method of adding ε-caprolactone monomer to the hard segment when poly (ε-caprolactone) is used for the soft segment. ..

[Cellulose fiber (B)]
The cellulose fiber (B) used in the present invention is obtained by mechanically or chemically defibrating the fiber as a raw material. The fiber as a raw material is not particularly limited, but one or more can be selected and used from among plant-derived fibers, animal-derived fibers, microorganism-derived fibers and the like.

The cellulose fiber (B) may have at least a part of functional groups or reactive groups modified or unmodified. Examples of the denaturation treatment include esterification and etherification.

In esterification, an acyl group such as an acetyl group is introduced as a substituent by an esterifying agent. Examples of the esterifying agent include carboxylic acid, carboxylic acid anhydride, and carboxylic acid halide, and acetic acid, propionic acid, butyric acid, acrylic acid, methacrylic acid, and derivatives thereof are preferable.

Examples of etherification include alkyl etherification and silyl etherification. As the alkyl etherifying agent, alkyl halides such as methyl chloride and ethyl chloride, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, and alkylene oxides such as ethylene oxide and propylene oxide are preferable. Examples of the silyl etherifying agent include alkoxysilanes such as n-butoxytrimethylsilane, tert-butoxytrimethylsilane, sec-butoxytrimethylsilane, isobutoxytrimethylsilane, ethoxytriethylsilane, octyldimethylethoxysilane, and cyclohexyloxytrimethylsilane, and butoxypoly. Alkoxysiloxanes such as dimethylsiloxane, disilazans such as hexamethyldisilazane, tetramethyldisilazane, diphenyltetramethyldisilazane, silylhalides such as trimethylsilylchloride and diphenylbutylchloride, and silyltrifluoromethanes such as tert-butyldimethylsilyltrifluoromethanesulfonate. Examples include sulfonate.

Further, the cellulose fiber (B) may contain a dispersant (C). The dispersant (C) may have, for example, a functional group capable of binding to a hydroxy group of a cellulose fiber, a cationic group such as ammonium, phosphonium or sulfonium, or a carboxyl group, a phosphoric acid group, a sulfonic acid group or the like. It may have an anionic group of.

The ratio of the dispersant (C) is, for example, 1 part by mass or less, preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, and particularly preferably 0.1 part by mass or less with respect to 100 parts by mass of the cellulose fiber (B). It is 0.01 to 0.1 parts by mass.

As a method for producing the cellulose fiber (B), if it is a method by mechanical shearing, for example, pulp or the like is treated with hot water of 100 ° C. or higher, the hemicellulose portion is hydrolyzed to make it fragile, and then a high-pressure homogenizer is used. There is a method of defibrating by a crushing method such as a microfluidizer, a ball mill or a disc mill.

Examples of the chemical treatment method include the N-methylmorpholine-N-oxide (NMMO) method, the copper ammonia solution method, and the ionic liquid method.

The present invention exhibits excellent surface properties and fatigue properties by forming a network of cellulose fibers (B) in the thermoplastic polyester elastomer (A). The cellulose fiber (B) is 0.1 to 30 parts by mass, preferably 0.5 to 25 parts by mass, and more preferably 1 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic polyester elastomer (A) in the present invention. It is more preferably 1 to 10 parts by mass. When the amount of the cellulose fiber (B) is less than 0.1 parts by mass, the cellulose network is not formed, the effect of improving the surface characteristics, the fatigue characteristics and the wear characteristics cannot be obtained, and the cellulose fiber (B) is more than 30 parts by mass. If there are too many, the desired dispersion form will not be obtained, and there is a concern that the physical properties will deteriorate due to the aggregation of cellulose fibers.

[Other ingredients]
The resin composition of the present invention includes antioxidants such as aromatic amine-based, hindered phenol-based, sulfur-based, and phosphorus-based, hindered amine-based, benzotriazole-based, benzophenone-based, benzoate-based, triazole-based, nickel-based, and salicyl. It is preferable to add a light stabilizer such as a system. These may be used in combination of two or more.

The blending (content) amount of each of the above-mentioned antioxidants and / or light stabilizers is preferably 0.01 to 3 parts by mass, more preferably 0, with respect to 100 parts by mass of the thermoplastic polyester elastomer (A). It is 05 to 2 parts by mass, more preferably 0.1 to 1 part by mass. When two or more kinds of antioxidants and / or light stabilizers are blended, the upper limit of the total content is preferably 5 parts by mass.

If necessary, a cross-linking agent may be added to the thermoplastic polyester elastomer (A) as long as the effect of the present invention is not impaired. The cross-linking agent is not particularly limited as long as it is a cross-linking agent that reacts with the hydroxyl group or carboxyl group of the thermoplastic polyester elastomer (A), and for example, an epoxy-based cross-linking agent, a carbodiimide-based cross-linking agent, an isocyanate-based cross-linking agent, and the like. Examples thereof include an acid anhydride-based cross-linking agent, a silanol-based cross-linking agent, a melamine resin-based cross-linking agent, a metal salt-based cross-linking agent, a metal chelate-based cross-linking agent, and an amino resin-based cross-linking agent. The cross-linking agent may be used alone or in combination of two or more.

The epoxy-based cross-linking agent is not particularly limited as long as it is a polyfunctional epoxy compound having two or more epoxy groups (glycidyl groups) in the molecule, and specifically, 1,6-dihydroxynaphthalene having two epoxy groups. Diglycidyl ether, 1,3-bis (oxylanylmethoxy) benzene, 1,3,5-tris (2,3-epoxidepropyl) -1,3,5-triazine-2,4 with three epoxy groups , 6 (1H, 3H, 5H) -trione and diglycerol triglycidyl ether, 1-chloro-2,3-epoxide propane, formaldehyde, 2,7-naphthalenediol polycondensate and pentaerythritol poly with four epoxy groups Examples include glycidyl ether. Above all, a polyfunctional epoxy compound having heat resistance in the skeleton is preferable. In particular, a bifunctional or tetrafunctional epoxy compound having a naphthalene structure as a skeleton, or a trifunctional epoxy compound having a triazine structure as a skeleton is preferable. Considering the degree of increase in the solution viscosity of the thermoplastic polyester elastomer (A), the effect of efficiently lowering the acid value of the thermoplastic polyester elastomer (A), and the degree of gelation due to the aggregation and solidification of the epoxy itself. Then, a bifunctional or trifunctional epoxy compound is preferable.

As specific examples of commercially available epoxy-based cross-linking agents, for example, sorbitol polyglycidyl ether type, polyglycerol polyglycidyl ether type, diglycerol polyglycidyl ether type, polyethylene glycol diglycidyl ether type and the like can be used. .. For example, the epoxy compound "Denacol" manufactured by Nagase Chemtech Co., Ltd. (EX-611, EX-614, EX-614B, EX-512, EX-521, EX-421, EX-313, EX-810, EX-830, EX-850, etc.), Diepoxy / polyepoxy compounds manufactured by Sakamoto Yakuhin Kogyo Co., Ltd. (SR-EG, SR-8EG, SR-GLG, etc.), Epoxy cross-linking agent "EPICLON" EM-85 manufactured by Dainippon Ink Industry Co., Ltd. -75W, CR-5L and the like can be mentioned.

In addition, a vinyl aromatic monomer containing two or more glycidyl groups per molecule, having a weight average molecular weight of 4000 to 25000, (X) 20 to 99% by mass, and (Y) 1 to 80% by mass glycidyl (Y). Examples thereof include a styrene-based polymer composed of a (meth) acrylate and a (Z) vinyl group-containing monomer other than (X) which does not contain 0 to 79% by mass of an epoxy group. More preferably, the copolymer is composed of 20 to 99% by mass of (X), 1 to 80% by mass of (Y), and 0 to 40% by mass of (Z), and more preferably 25 to 90% by mass of (X). It is a copolymer composed of% by mass, (Y) 10 to 75% by mass, and (Z) 0 to 35% by mass. Examples of the (X) vinyl aromatic monomer include styrene and α-methylstyrene. Examples of the (Y) glycidylalkyl (meth) acrylate include glycidyl (meth) acrylic acid, (meth) acrylic acid ester having a cyclohexene oxide structure, (meth) acrylic glycidyl ether, and the like. Glycidyl (meth) acrylate is preferable because of its high reactivity. Examples of the (Z) other vinyl group-containing monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. (Meta) acrylic having an alkyl group having 1 to 22 carbon atoms (the alkyl group may be a straight chain or a branched chain) such as cyclohexyl (meth) acrylate, stearyl (meth) acrylate, and methoxyethyl (meth) acrylate. Acid alkyl ester, (meth) acrylic acid polyalkylene glycol ester, (meth) acrylic acid alkoxyalkyl ester, (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid dialkylaminoalkyl ester, (meth) acrylic acid benzyl ester, Examples thereof include (meth) acrylic acid phenoxyalkyl ester, (meth) acrylic acid isobornyl ester, and (meth) acrylic acid alkoxysilylalkyl ester. Further, vinyl esters such as (meth) acrylamide, (meth) acrylic dialkylamide and vinyl acetate, vinyl ethers, aromatic vinyl-based monomers such as (meth) allyl ethers, and α-olefin monomers such as ethylene and propylene. Etc. can also be used as the above-mentioned (Z) and other vinyl group-containing monomers.
The weight average molecular weight of the copolymer is preferably 4000 to 25000. The weight average molecular weight is more preferably 5000 to 15000. The epoxy value of the copolymer is preferably 400 to 2500 equivalents / 1 × 10 ⁶ g, more preferably 500 to 1500 equivalents / 1 × 10 ⁶ g, still more preferably 600 to 1000 equivalents / 1 × 10 ⁶ g. g.
As an epoxy-based cross-linking agent satisfying such conditions, a styrene / glycidyl acrylate copolymer (trade name: UG series of ARUFON) manufactured by Toagosei Co., Ltd. can be used.

The carbodiimide-based cross-linking agent is not particularly limited as long as it is a polycarbodiimide having two or more carbodiimide groups (-N = C = N- structure) in one molecule, and is, for example, an aliphatic polycarbodiimide or an alicyclic poly. Examples include carbodiimide, aromatic polycarbodiimide and copolymers thereof. An aliphatic polycarbodiimide compound or an alicyclic polycarbodiimide compound is preferable.

The polycarbodiimide compound can be obtained, for example, by a decarbonization reaction of the diisocyanate compound. Examples of the diisocyanate compound that can be used here include 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylenediocyanate, 1,4-phenylenediocyanate, and 2,4-tolylene diisocyanate. , 2,6-Toluene diisocyanate, 1,5-naphthylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, Examples thereof include 1,3,5-triisopropylphenylene-2,4-diisocyanate. Only one of these may be used, or two or more thereof may be copolymerized and used. Further, a branched structure may be introduced, or a functional group other than a carbodiimide group or an isocyanate group may be introduced by copolymerization. Further, although the terminal isocyanate can be used as it is, the degree of polymerization may be controlled by reacting the terminal isocyanate, or a part of the terminal isocyanate may be blocked.

As the polycarbodiimide compound, alicyclic polycarbodiimide derived from dicyclohexylmethane diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate and the like is particularly preferable, and polycarbodiimide derived from dicyclohexylmethane diisocyanate and isophorone diisocyanate is particularly preferable.

The polycarbodiimide compound preferably contains 2 to 50 carbodiimide groups per molecule in terms of stability and handleability. More preferably, each molecule contains 5 to 30 carbodiimide groups. The number of carbodiimides in the polycarbodiimide molecule (that is, the number of carbodiimide groups) corresponds to the degree of polymerization if the polycarbodiimide is obtained from a diisocyanate compound. For example, the degree of polymerization of polycarbodiimide obtained by connecting 21 diisocyanate compounds in a chain is 20 and the number of carbodiimide groups in the molecular chain is 20. Usually, a polycarbodiimide compound is a mixture of molecules of various lengths, and the number of carbodiimide groups is represented by an average value. If it has a carbodiimide group in the above range and is solid near room temperature, it can be powdered, so that it has excellent workability and compatibility when mixed with the thermoplastic polyester elastomer (A), and has uniform reactivity and bleed-out resistance. It is also preferable in terms of. The number of carbodiimide groups can be measured, for example, by using a conventional method (a method of dissolving with an amine and performing back titration with hydrochloric acid).

The polycarbodiimide compound has an isocyanate group at the terminal, and the isocyanate group content is preferably 0.5 to 4% by mass, which is preferable from the viewpoint of stability and handleability. More preferably, the isocyanate group content is 1 to 3% by mass. In particular, it is preferable that the polycarbodiimide derived from dicyclohexylmethane diisocyanate or isophorone diisocyanate has an isocyanate group content in the above range. The isocyanate group content can be measured by using a conventional method (a method of dissolving with amine and performing back titration with hydrochloric acid).

Examples of the isocyanate-based cross-linking agent include the above-mentioned polycarbodiimide compound containing an isocyanate group and the isocyanate compound which is a raw material of the above-mentioned polycarbodiimide compound.

As the acid anhydride-based cross-linking agent, a compound containing 2 to 4 anhydrides per molecule is preferable in terms of stability and handleability. Examples of such a compound include phthalic acid anhydride, trimellitic acid anhydride, pyromellitic acid anhydride and the like.

The amount (content) of the cross-linking agent used is appropriately adjusted depending on the extrusion conditions and the like, and is, for example, 0.1 to 4.5 parts by mass with respect to 100 parts by mass of the thermoplastic polyester elastomer (A). It is preferably 0.1 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass.

Further, in addition to the above-mentioned antioxidant, light stabilizer, and cross-linking agent, various additives can be added to the thermoplastic polyester elastomer (A) used in the present invention depending on the purpose. The type of such an additive is not particularly limited, and various additives can be used. Specifically, as additives, lubricants, fillers, flame retardants, flame retardant aids, mold release agents, antistatic agents, molecular modifiers such as peroxides, metal deactivators, organic and inorganic nuclei. Agents, neutralizers, antioxidants, antibacterial agents, fluorescent whitening agents, organic and inorganic pigments, as well as organic and inorganic phosphorus compounds used for the purpose of imparting flame retardancy and thermal stability. And so on. When an additive is contained, the content thereof (total content when a plurality of additives are used) is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 20% by mass or less in the resin composition. Is 10% by mass or less, particularly preferably 5% by mass or less.

As a method for determining the composition and composition ratio of the polyester elastomer resin composition used in the present invention, it is also possible to calculate from the proton integral ratio of ¹ H-NMR measured by dissolving the sample in a solvent such as deuterated chloroform. be.

The polyester elastomer resin composition of the present invention is characterized by having a tensile elongation of 300% or more as described in the section of Examples described later. The tensile elongation is the elongation at the time of cutting measured according to JIS K6251 as described in the section of Examples.

[Thermoplastic Polyester Elastomer Resin Composition]
Examples of the method for producing the thermoplastic polyester elastomer resin composition of the present invention include a method of melt-kneading each component by a conventionally known method. It is not particularly limited as long as the thermoplastic polyester elastomer (A) and the cellulose fiber (B) can be kneaded at least in a state where the thermoplastic polyester elastomer (A) is melted, and for example, a mixing roller, a kneader, an extruder and the like can be used. In the present invention, from the viewpoint of dispersibility of the cellulose fiber (B), a kneader, an extruder or the like capable of applying a particularly high shearing force is preferable, and a twin-screw extruder is more preferable.

The average fiber length of the cellulose fiber (B) in the resin composition is 100 to 2000 μm, preferably 100 to 800 μm, more preferably 200 to 600 μm, and further preferably 400 to 600 μm. If it is less than 100 μm, sufficient surface characteristics, fatigue characteristics and wear characteristics cannot be exhibited, and if it exceeds 2000 μm, fibers are likely to be entangled with each other and large aggregates are likely to be generated. The average fiber length is a number average fiber length measured by the method described in the section of Examples described later.

The average fiber diameter of the cellulose fibers in the resin composition is 0.5 to 50 μm, preferably 1 to 30 μm, more preferably 1 to 20 μm, still more preferably 5 to 15 μm, and particularly preferably. It is 6 to 10 μm. If the average fiber diameter is less than 0.5 μm, the fibers are likely to be entangled with each other and aggregates are likely to be generated. On the other hand, if it exceeds 50 μm, the elongation tends to decrease and defects in the resin composition tend to occur. The average fiber diameter is a number average fiber diameter measured by the method described in the section of Examples described later.

The thermoplastic polyester elastomer resin composition of the present invention suppresses the aggregation of cellulose and maintains the performance as an elastomer by setting the average fiber diameter and the average fiber length of the cellulose fibers in the resin composition within a specific range. However, the surface characteristics, fatigue characteristics and wear characteristics can be improved.

The thermoplastic polyester elastomer resin composition of the present invention can be made into a molded product by a known molding method. The molding method is not specified, and can be suitably used in injection molding, blow molding, extrusion molding, foam molding, malformed molding, calendar molding, and various other molding methods. Of these, injection molding is preferable.

Examples are given below in order to demonstrate the effects of the present invention, but the present invention is not limited to these examples.

The following raw materials were used in the following examples and comparative examples.
[Thermoplastic Polyester Elastomer (A)]
(Polyester Elastomer A-1)
According to the method described in JP-A-9-59491, dimethyl terephthalate, 1,4-butanediol, and poly (tetramethylene oxide) glycol having a number average molecular weight of 1000 are used as raw materials, and the soft segment content is 44% by mass. The thermoplastic polyester elastomer of No. 1 was produced and used as Polyester Elastomer A-1.

[Cellulose fiber (B)]
(Cellulose fiber B-1)
Using an autoclave, the pulp is heated with hot water at 120 ° C. or higher for 3 hours, and the purified pulp from which the hemicellulose portion has been removed is squeezed and beaten into heavy water so that the solid content ratio becomes 1.5% by mass. After shortening and fibrillation, defibrated cellulose having an average fiber diameter of 10 μm and an average fiber length of 1000 μm was obtained by defibrating with a high-pressure homogenizer at the same concentration.
(Cellulose fiber B-2)
By using a high-pressure homogenizer in the same manner as the cellulose fiber B-1 and changing the beating blade and the beating time, defibrated cellulose having an average fiber diameter of 10 μm and an average fiber length of 2800 μm was obtained.
(Cellulose fiber B-3)
By using a high-pressure homogenizer in the same manner as the cellulose fiber B-1 and changing the beating blade and the beating time to be used, defibrated cellulose having an average fiber diameter of 200 nm and an average fiber length of 250 μm was obtained.
(Cellulose fiber B-4)
By using a high-pressure homogenizer in the same manner as the cellulose fiber B-1 and changing the beating blade and the beating time, defibrated cellulose having an average fiber diameter of 100 μm and an average fiber length of 1500 μm was obtained.

[Average fiber diameter / average fiber length of cellulose fibers used as raw materials]
The cellulose component was made into a pure water suspension at a concentration of 1% by mass, the aqueous dispersion dispersed with a high shear homogenizer was diluted with pure water to 0.1 to 0.5% by mass, cast, and air-dried and scanned. It was taken with an electron microscope. Cellulose fibers were image-processed, the diameters and fiber lengths of 50 fibers were measured using analysis software, and the average values were calculated. The fiber diameter was measured at the thickest part of one fiber. The fiber length of the non-straight fiber was measured by dividing the length at multiple points.

Examples 1 to 6, Comparative Examples 1 to 7
Cellulose fibers were kneaded with 100 parts by mass of a thermoplastic polyester elastomer using a twin-screw extruder according to the compounding composition shown in Table 1, and then pelletized. The length and diameter of the cellulose fibers were adjusted according to the ejection speed and the number of revolutions at the time of extrusion. Comparative Example 4 was produced by repeating kneading with a twin-screw screw extruder three times. The following evaluation was performed using the pellets of this polyester elastomer resin composition. The results are shown in Table 1.

[Average fiber diameter / average fiber length of cellulose fibers in resin composition]
A sheet having a width of 100 mm, a length of 100 mm, and a thickness of 50 μm was prepared from pellets by heat pressing, the cellulose fibers in the resin composition photographed by an optical microscope were image-processed, and 50 fiber diameters and fiber lengths were processed using analysis software. Was measured, and the average value was calculated. The fiber diameter was measured at the thickest part of one fiber. The fiber length of the non-straight fiber was measured by dividing the length at multiple points.

[Dispersity]
A sheet having a width of 100 mm, a length of 100 mm, and a thickness of 50 μm was prepared from the pellets by heat pressing, and aggregates on the sheet surface were observed. When there was no agglomerate or the diameter of the agglomerate was less than 100 μm: 〇, when the diameter of the agglomerate was 100 μm to 300 μm: Δ, and when the diameter of the agglomerate was more than 300 μm: ×. When there were multiple agglomerates, the largest agglomerate was evaluated.

[Tensile elongation]
The measurement was carried out by the method described in JIS K6251. The test piece used was an injection-molded product having a width of 100 mm, a length of 100 mm, and a thickness of 2.0 mm, punched into a JIS No. 3 dumbbell shape parallel to the flow direction of the resin.

[Thrust wear resistance]
An injection-molded product with a width of 50 mm, a length of 50 mm, and a thickness of 2 mm is brought into contact with the end face of a hollow cylindrical mating material made of S-45C having an outer diameter of 20 mm, an inner diameter of 14.2 mm, and a length of 20 mm so that the surface pressure becomes 1.0 MPa. A constant load was applied to the product, and the amount of wear when the injection-molded product was rotated at 15 cm / s for 30 minutes was measured.

[Repeat fatigue characteristics]
An injection-molded article having a width of 100 mm, a length of 100 mm, and a thickness of 2.0 mm was punched out from a strip-shaped test piece having a length of 80 mm and a width of 10 mm in parallel with the flow direction of the resin. Using a fatigue / durability tester Servo Pulser manufactured by Shimadzu Corporation, the load was repeatedly applied in a frequency of 30 Hz, a grip distance of 30 mm, and a tension mode, and the end point was when the amplitude became ± 8 mm. The load at which the number of repeated fatigues was ¹⁰⁷ or more was measured.

As is clear from Table 1, all of Examples 1 to 6 within the scope of the present invention are superior to Comparative Example 1 containing no cellulose fiber while maintaining the tensile elongation performance as an elastomer. It exhibits surface properties and fatigue properties, and has excellent dispersibility of cellulose fibers in the resin. On the other hand, in Comparative Example 2 in which the number of portions of the cellulose fiber added in the resin is small and Comparative Example 4 in which the fiber length is short, the dispersibility of the cellulose is excellent, but the effect on the wear property and the fatigue property is low. In Comparative Example 3 in which the number of portions of the cellulose fibers added is large, Comparative Example 5 in which the fiber length is long, and Comparative Example 6 in which the fiber diameter is small, although excellent wear characteristics and fatigue characteristics are exhibited, the cellulose fibers are aggregated and dispersible. Inferior. Further, in Comparative Example 7 having a large fiber diameter, the elongation was lowered, and the fatigue characteristics were also inferior to those in Example 2.

Further, the press sheets obtained from Example 2 and Comparative Example 3 were observed with an optical electron microscope. A photograph of Example 2 is shown in FIG. 1A, and a photograph of Comparative Example 3 is shown in FIG. 1B. From FIGS. 1A and 1B, in Example 2, the cellulose fibers were uniformly dispersed to form a network in the resin, whereas in Comparative Example 3, agglomerates having a size of 300 μm or more were observed and dispersed. Is found to be non-uniform.

Possibility of industrial use

Claims

A hard segment made of a polyester composed of an aromatic dicarboxylic acid and an aliphatic and / or alicyclic diol, and at least one soft segment selected from an aliphatic polyether, an aliphatic polyester, and an aliphatic polycarbonate are used. It is a thermoplastic polyester elastomer resin composition containing 0.1 to 30 parts by mass of a cellulose fiber (B) with respect to 100 parts by mass of the bonded thermoplastic polyester elastomer (A), and the cellulose fiber (B) in the resin composition. ) Is a thermoplastic polyester elastomer resin composition having an average fiber length of 100 to 2000 μm and an average fiber diameter of 0.5 to 50 μm.
The heat according to claim 1, wherein the content of the cellulose fiber (B) is 1 to 10 parts by mass, the average fiber length of the cellulose fiber in the resin composition is 100 to 800 μm, and the average fiber diameter is 1 to 30 μm. Plastic polyester elastomer resin composition.
The thermoplastic polyester elastomer resin composition according to claim 1 or 2, wherein the cellulose fiber (B) is a modified cellulose fiber.
The thermoplastic polyester elastomer resin composition according to any one of claims 1 to 3, further containing a dispersant (C).
The thermoplastic polyester elastomer resin composition according to any one of claims 1 to 4, wherein the tensile elongation measured in accordance with JIS K6251 of the resin composition is 300% or more.
The production of the thermoplastic polyester elastomer resin composition according to any one of claims 1 to 5, wherein the cellulose fiber (B) is dispersed in the thermoplastic polyester elastomer (A) using a twin-screw kneader. Method.
A molded product made of the thermoplastic polyester elastomer resin composition according to any one of claims 1 to 5.