JPH09310017A - Resin composition and its molding product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition, comprising a thermoplastic polyurethane, a specific polymer and a polyacetal resin and excellent in tensile strength and elongation, impact resistance at normal and low temperatures and molding processability. SOLUTION: This resin composition comprises (A) a thermoplastic polyurethane, (B) a polymer, having a molecular chain consisting essentially of (i) a conjugated diene compound unit which may be hydrogenated and (ii) an aromatic vinyl compound unit at (10/90) to (90/10) molar ratio of the units (i)/(ii) and further hydroxyl groups at the terminals of the molecular main chain and (C) a polyacetal resin [with the proviso that at least a part of the component A and at least a part of the component B may be present in the form of (D) a block copolymer which can be formed by chemically reacting the component B with the component A at the position of terminal OH groups]. The amounts of the components A and B are respectively 2.5-90wt.% based on the total weight of the components A to C and the amount of the component C is 5-95wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition containing a polyacetal resin, a thermoplastic polyurethane, and a specific polymer having a hydroxyl group at a terminal, and a molded article made of the resin composition. INDUSTRIAL APPLICABILITY The resin composition of the present invention is excellent in mechanical properties such as tensile strength and elongation, impact resistance at room temperature and low temperature; abrasion resistance; molding processability and the like, and is useful as a material for various molded products.

[0002]

2. Description of the Related Art Polyacetal resins are widely used as engineering resins having excellent tensile strength and elongation, electrical properties, chemical resistance, heat resistance and the like. However, the polyacetal resin is inferior in impact resistance, and therefore, a technique of blending a rubber component is known as a method for improving impact resistance. Since the polyacetal resin has a high polarity, a highly polar thermoplastic polyurethane or the like is used as the rubber component so that the rubber component can be finely dispersed in the matrix of the polyacetal resin to effectively exhibit impact resistance. ing. However, even in the case of a resin composition obtained by blending a polyacetal resin with a thermoplastic polyurethane, there are still points to be improved in impact resistance at low temperatures.

On the other hand, attempts have been made to add a styrene block copolymer in order to improve the impact resistance and weather resistance of the polyacetal resin at low temperatures. However, in general, the styrene block copolymer is not finely dispersed, and when the resin composition is used as a molded product, surface layer peeling is severe and the tensile elongation is significantly reduced.

In addition, the polyacetal resin has a softening point below the microcrystalline melting point of the polyacetal resin and -120.degree.
A molding composition obtained by blending an elastomer having a second-order transition temperature of + 30 ° C. and a thermoplastic polyurethane,
It is known to have good impact resistance (Japanese Examined Patent Publication 6)
3-26138). However, in the molding composition, the performance of tensile strength and elongation derived from the polyacetal resin is greatly reduced, and further, the impact resistance may be insufficient depending on the application.

[0005]

A first object of the present invention is to provide a resin composition containing a polyacetal resin and a thermoplastic polyurethane, which is excellent not only in tensile strength and elongation and impact resistance at room temperature but also in low temperature. Another object of the present invention is to provide a resin composition having improved impact resistance. A second object of the present invention is to provide a molded product in which the above features are effectively utilized.

[0006]

Means for Solving the Problems As a result of studies to achieve the above object, the present inventors have found that a composition having a polyacetal resin and a thermoplastic polyurethane is further blended with a polymer having a specific chemical structure. It was found that not only the tensile strength and elongation and the impact resistance at room temperature are excellent, but also the impact resistance at low temperature is highly improved, and as a result of further studies, the present invention has been completed.

That is, firstly, the present invention relates to (1) a thermoplastic polyurethane (A); a conjugated diene compound unit (I) and an aromatic vinyl compound unit ((I) whose molecular main chain is mainly hydrogenated. II) consisting of units (I) /
It contains a polymer (B) having a molar ratio of the unit (II) in the range of 10/90 to 90/10 and having a hydroxyl group at the terminal of the molecular main chain; and a polyacetal resin (C) (however, heat At least a part of the plastic polyurethane (A) and at least a part of the polymer (B) are the polymer (B).
At the position of the hydroxyl group at the terminal of the thermoplastic polyurethane (A)
May exist in the form of a block copolymer (D) which can be formed by a chemical reaction with (2) above (A), (B)
And the proportion of (A) is 2.5 to 90% by weight and the proportion of (B) is 2.5 to 9 based on the total weight of (C).
It is 0% by weight and the proportion of (C) is 5 to 95% by weight, which is a resin composition.

Secondly, the present invention is a molded article made of the above resin composition.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the thermoplastic polyurethane (A) can be obtained, for example, by subjecting a polymer diol, an organic diisocyanate and a chain extender to a urethanization reaction.

As the polymer diol, ester polymer diols such as polyester diol, polycarbonate diol and polyester polycarbonate diol are preferable. The number average molecular weight of the polymeric diol is 1,5
It is preferably from 00 to 6,000, and from 2,000.
More preferably, it is 6,000. The number average molecular weight of the high molecular weight diols referred to in this specification is JIS
It is a number average molecular weight calculated based on a hydroxyl value measured according to K1577.

The polyester diol can be obtained, for example, by subjecting a dicarboxylic acid or an ester-forming derivative such as an ester or anhydride thereof and a low-molecular diol to a direct esterification reaction or transesterification reaction according to a conventional method. Examples of the dicarboxylic acid used as a raw material for producing the polyester diol include glutaric acid, adipic acid, pimelic acid, suberinism, azelaic acid, sebacic acid, dodecanedioic acid, 2-methylsuccinic acid,
2-methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,8-
Examples thereof include aliphatic dicarboxylic acids having 5 to 12 carbon atoms such as dimethyldecanedioic acid and 3,7-dimethyldecanedioic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and the like. One kind or two or more kinds can be used. Among these,
It is preferable to use an aliphatic dicarboxylic acid having 5 to 12 carbon atoms, and it is more preferable to use adipic acid, azelaic acid, sebacic acid, or the like. Examples of the low molecular weight diol used as a raw material for producing the polyester diol include ethylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol and 1,4-
Butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9
Examples thereof include aliphatic diols such as -nonanediol and 1,10-decanediol; alicyclic diols such as cyclohexanedimethanol and cyclohexanediol, and one or more of them can be used.

The above-mentioned polycarbonate diol can be obtained, for example, by reacting a low molecular weight diol with a carbonate compound such as dialkyl carbonate, alkylene carbonate or diaryl carbonate. As the low-molecular diol which is a raw material for producing a polycarbonate diol, the low-molecular diol exemplified above as a raw material for producing a polyester diol can be used. Examples of the dialkyl carbonate include dimethyl carbonate and diethyl carbonate, examples of the alkylene carbonate include ethylene carbonate, and examples of the diaryl carbonate include diphenyl carbonate.

The above polyester polycarbonate diol can be obtained, for example, by simultaneously reacting a low molecular weight diol, a dicarboxylic acid and a carbonate compound. Alternatively, the polyester polycarbonate diol can be obtained by previously synthesizing a polyester diol and a polycarbonate diol by the above-mentioned method and then reacting them with a carbonate compound or with a diol and a dicarboxylic acid.

The type of organic diisocyanate used for producing the thermoplastic polyurethane (A) is not particularly limited,
Although any of the organic diisocyanates conventionally used for the production of ordinary thermoplastic polyurethane can be used, aromatic, alicyclic or aliphatic diisocyanates having a molecular weight of 500 or less can be used alone or in combination of two or more. Preferably. Suitable examples of the organic diisocyanate include 4,4′-diphenylmethane diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate,
Isophorone diisocyanate, tolylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-
Examples thereof include dicyclohexylmethane diisocyanate, and one or more of these can be used. Among these, it is preferable to use 4,4′-diphenylmethane diisocyanate. In addition, a tri- or more functional polyisocyanate such as triphenylmethane triisocyanate can be used in a small amount as necessary.

The type of chain extender used in the production of the thermoplastic polyurethane (A) is not particularly limited, and any of the chain extenders conventionally used in the production of ordinary thermoplastic polyurethane can be used. Isocyanate group (-N
It is preferable to use a low molecular weight compound having a molecular weight of 300 or less, which has two or more (preferably two) active hydrogen atoms capable of reacting with CO) in the molecule. As the low molecular weight compound,
For example, ethylene glycol, propylene glycol,
1,4-butanediol, 1,6-hexanediol,
1,4-bis (β-hydroxyethoxy) benzene,
1,4-cyclohexanediol, bis- (β-hydroxyethyl) terephthalate, xylylene glycol and other diols; hydrazine, ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine or its derivatives, phenylenediamine, tolylenediamine. , Xylenediamine, adipic acid dihydrazide, isophthalic acid dihydrazide, and other diamines; aminoethyl alcohol, aminopropyl alcohol, and other amino alcohols, and the like, and one or more of these can be used. Among these, it is preferable to use an aliphatic diol having 2 to 10 carbon atoms, and it is more preferable to use 1,4-butanediol. The amount of the chain extender used is not particularly limited and can be appropriately selected according to the hardness to be imparted to the polyurethane, but is usually used in a ratio of 0.1 to 10 mol per mol of the polymer diol. Preferably
It is more preferable to use it in a ratio of 0.3 to 7 mol.

In the production of the thermoplastic polyurethane (A), the above-mentioned polymer diol, organic diisocyanate and chain extender are added to the following formula;

[0017]

## EQU2 ## 0.9 ≦ b / (a + c) ≦ 1.1

(Wherein a represents the number of moles of the polymeric diol, b represents the number of moles of the organic diisocyanate, and c represents the number of moles of the chain extender).

It is preferable to carry out the reaction at a ratio that satisfies the above condition. By using a thermoplastic polyurethane obtained by reacting a polymer diol, an organic diisocyanate and a chain extender in a ratio satisfying the above mathematical formula, a resin composition having more excellent mechanical performance, abrasion resistance and moldability The thing is obtained.

The method for producing the thermoplastic polyurethane (A) is not particularly limited, and the above-mentioned polymer diol, organic diisocyanate and chain extender are used, and the known urethanization reaction technique is used to carry out the prepolymer method, one-step method. It can be manufactured by an arbitrary method such as a shot method. Of which
It is preferable to carry out melt polymerization in the substantial absence of a solvent, and it is particularly preferable to carry out continuous melt polymerization using a multi-screw extruder.

In producing the thermoplastic polyurethane (A) using the above-mentioned polymer diol, organic diisocyanate and chain extender, a tin-based urethane-forming catalyst having catalytic activity for the urethane-forming reaction is used. Good. The use of the tin-based urethane-forming catalyst is effective in rapidly increasing the molecular weight of polyurethane and obtaining a polyurethane having various better physical properties. Examples of the tin-based urethane-forming catalyst include dialkyltin diacylates such as dibutyltin diacetate and dibutyltin dilaurate; dialkyltin bismercaptocarboxylic acid ester salts such as dibutyltin bis (3-mercaptopropionic acid ethoxybutyl ester) salts. be able to. When a tin-based urethane-forming catalyst is used, the amount used is the weight of the polyurethane (that is, the polymer diol used for producing the polyurethane, the organic diisocyanate,
(Total weight of reactive raw material compounds such as chain extenders),
It is preferably 0.5 to 15 ppm in terms of tin atom.

The inherent viscosity of the thermoplastic polyurethane (A) is dissolved in an N, N-dimethylformamide solution containing 0.05 mol / liter of n-butylamine so that the concentration of the thermoplastic polyurethane is 0.5 g / dl. Then 3
When measured at 0 ° C., it is preferably 0.5 to 2.0 dl / g because a resin composition having good mechanical properties, abrasion resistance, non-adhesiveness, etc. can be obtained. From this viewpoint, the logarithmic viscosity is more preferably 0.8 to 1.9 dl / g.

In the polymer (B) having a hydroxyl group at the terminal used in the present invention, the molecular main chain is mainly a hydrogenated conjugated diene compound unit (I) and an aromatic vinyl compound unit (II). ).

The optionally hydrogenated conjugated diene compound unit (I) constituting the polymer (B) is a unit derived from the conjugated diene compound or a unit in the hydrogenated form. Examples of the conjugated diene compound include isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,
3-hexadiene and the like can be mentioned, and of these, isoprene is preferable. As the unit (I), one type or two or more types can be contained in the polymer (B). The carbon-carbon double bond in the unit (I) existing in the main chain of the polymer (B) is at least partially hydrogenated, which results in a resin composition excellent in heat deterioration resistance and weather resistance. It is preferable in that it can be obtained. In this respect, 50 of the carbon-carbon double bonds in unit (I)
% Or more is hydrogenated (that is, the degree of unsaturation is 5
0% or less) is more preferable, and 80% or more is hydrogenated (that is, the degree of unsaturation is 20% or less) is particularly preferable. Examples of the aromatic vinyl compound unit (II) constituting the polymer (B) include styrene,
Examples thereof include units derived from aromatic vinyl compounds such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, vinylnaphthalene and vinylanthracene. Of these, units derived from styrene are preferred. The unit (II) may be one or two in the polymer (B).
More than one seed can be included.

The unit (I) / unit (II) molar ratio provides good compatibility between the polymer (B) and the polyacetal resin (C), and a resin composition excellent in mechanical performance and abrasion resistance. Therefore, it is within the range of 10/90 to 90/10. From this viewpoint, the molar ratio of unit (I) / unit (II) is more preferably within the range of 20/80 to 70/30. Unit (I) in main chain of polymer (B)
The arrangement of the units (II) and the units (II) may be in any of random, block and tapered block forms, but the compatibility of the resulting resin composition is better and the mechanical performance, molding process It is preferable that each unit is arranged in a block shape in terms of more excellent properties. That is, the polymer (B) is a block copolymer containing at least one polymer block mainly composed of the unit (I) and at least one polymer block mainly composed of the aromatic vinyl compound unit (II). It is preferable to have a main chain structure of

The polymer (B) must contain a hydroxyl group at the terminal of the main chain. The hydroxyl group content of the polymer (B) is
The average value per molecule is preferably 0.5 to 2, and more preferably 0.8 to 1.5.
Those having no hydroxyl group at the end have insufficient affinity with the thermoplastic polyurethane (A) and the affinity with the polyacetal resin (C), and can be sufficiently finely dispersed in these resin compositions. As a result, tensile strength, impact resistance, wear resistance, etc. are insufficient.

The number average molecular weight of the polymer (B) is preferably in the range of 1,000 to 300,000 from the viewpoint of obtaining a resin composition having an excellent balance in mechanical performance, moldability and the like. , 5,000 to 150,000 is more preferable. The main chain of the polymer (B) has a structure of a block copolymer having at least one polymer block mainly composed of the unit (I) and at least one polymer block mainly composed of the unit (II). When having, the number average molecular weight of the polymer block mainly composed of the unit (I) is preferably in the range of 100 to 270,000, and more preferably in the range of 10,000 to 200,000. In that case, the unit (I
The number average molecular weight of the polymer block consisting of I) is 100-
It is preferably in the range of 270,000, and 3,000
More preferably, it is in the range of 0 to 150,000.

The method for producing the polymer (B) is not particularly limited. For example, addition-copolymerization of a monomer having a conjugated diene compound and an aromatic vinyl compound as a main component by anionic living polymerization using an organic alkali metal catalyst such as butyllithium, mainly, a conjugated diene compound unit not hydrogenated and A living polymer comprising an aromatic vinyl compound unit (II) is obtained, and its polymerization active terminal is treated with an alkylene oxide such as ethylene oxide or propylene oxide to introduce a hydroxyl group at the terminal of the main chain. The polymer (B) can be obtained by hydrogenating the conjugated diene compound unit using the above method. As described above, the conjugated diene compound unit (I) is preferably partially hydrogenated or completely hydrogenated. For the hydrogenation reaction of the conjugated diene compound unit, a homogeneous catalyst or a heterogeneous catalyst can be used as a catalyst. As the homogeneous catalyst, for example, an organic transition metal catalyst (nickel acetylacetonate, cobalt acetylacetonate, nickel naphthenate, cobalt naphthenate, etc.) and an alkyl compound of a metal such as aluminum, an alkali metal or an alkaline earth metal is used. Ziegler catalysts in combination can be mentioned.
These catalysts are preferably used in a proportion of 0.01 to 0.1 mol% with respect to the carbon-carbon double bond contained in the conjugated diene compound unit. The hydrogenation reaction is usually
It is carried out at a temperature of room temperature to 160 ° C. and a normal pressure to 50 kg / cm ² of hydrogen pressure, and is completed in about 1 to 50 hours.

In the resin composition of the present invention, at least a part of the thermoplastic polyurethane (A) and at least a part of the polymer (B) having a hydroxyl group at the end are linked to the end of the polymer (B). It may be present in the form of a block copolymer which can be formed by a chemical reaction with the thermoplastic polyurethane (A) at the position of the hydroxyl group. The block copolymer is a block copolymer (D) having a polymer block composed of the thermoplastic polyurethane (A) and a polymer block composed of the polymer (B).

The polyacetal resin (C) used in the present invention is a polymer compound having an oxymethylene group as a main constituent unit, and is a polyoxymethylene homopolymer, a copolymer containing a small amount of another constituent unit in addition to the oxymethylene group, It may be either a terpolymer or a block copolymer. Also, the molecular chain is not only linear, but also has a branched structure,
It may have a crosslinked structure.

The resin composition of the present invention contains the thermoplastic polyurethane (A) based on the total weight of the thermoplastic polyurethane (A), the polymer having a hydroxyl group at the terminal (B) and the polyacetal resin (C). 5 to 90% by weight, 2.5 to 90% by weight of the polymer (B) having a hydroxyl group at the terminal, and 5 to 95% by weight of the polyacetal resin (C), respectively. In the present invention, the block of the thermoplastic polyurethane (A) and the polymer (B) incorporated in the molecule of the block copolymer (D).
The weights of the blocks in Table 1 add to the weight of the thermoplastic polyurethane (A) and the weight of the polymer (B), respectively.

If the content of the thermoplastic polyurethane (A) is less than 2.5% by weight, impact resistance and tensile elongation at room temperature of the obtained resin composition are insufficient, which is not preferable. When the content of the thermoplastic polyurethane (A) exceeds 90% by weight, the elastic modulus of the obtained resin composition is significantly lowered, which is not preferable. When the content of the polymer (B) having a hydroxyl group at the terminal is less than 2.5% by weight, the effect of improving the impact resistance of the resulting resin composition, particularly the effect of improving the impact resistance at low temperature, is not achieved. It is insufficient and not preferable. When the content of the polymer (B) having a hydroxyl group at the terminal exceeds 90% by weight, the elastic modulus of the obtained resin composition is significantly lowered, which is not preferable. When the content of the polyacetal resin (C) is less than 5% by weight, the tensile strength and the like of the obtained resin composition are insufficient, which is not preferable. Further, when the content of the polyacetal resin (C) exceeds 95% by weight, the resulting resin composition is insufficient in impact resistance, which is not preferable. Thermoplastic polyurethane (A), a polymer having a hydroxyl group at the terminal (from the viewpoint of obtaining a resin composition having particularly excellent total performance in mechanical properties such as tensile strength and elongation, impact resistance at room temperature and low temperature, etc. Based on the total weight of B) and the polyacetal resin (C), the content of (A) is 2.5-47.5.
It is preferable that the content of (B) is 2.5 to 47.5% by weight, and the content of (C) is 50 to 95% by weight. From the same point, (A) /
The weight ratio of (B) is preferably 2/8 to 8/2.

The resin composition of the present invention contains a thermoplastic polyurethane (A), a polymer having a hydroxyl group at the terminal (B) and a polyacetal resin (C) as essential components, but if desired, the effect of the present invention is obtained. Additives such as antioxidants, ultraviolet absorbers, antiaging agents, antistatic agents, antihydrolysis agents, plasticizers, etc., in amounts that do not adversely affect the above; fillers such as talc, mica and calcium carbonate; Polyolefins such as polypropylene and polyethylene, polystyrene, polystyrenes such as HIPS, PP
Polymers such as E and various TPEs may be further contained.

The resin composition of the present invention can be produced by mixing the thermoplastic polyurethane (A), the polymer having a hydroxyl group at the terminal (B), the polyacetal resin (C), and optionally other components. Yes (however,
A part of (A) and a part of (B) may be used for mixing in the form of block copolymer (D)). As the mixing method, various methods can be adopted according to the method used for producing a known resin composition, and the mixing order of the respective components is not particularly limited. However,
Tensile strength and elongation, from the viewpoint that it is possible to reproducibly obtain a resin composition having particularly excellent mechanical properties such as impact resistance at room temperature and low temperature with good reproducibility, a method of kneading each component under melting conditions is preferable, A method in which a thermoplastic polyurethane (A) and a polymer (B) having a hydroxyl group at the end are melt-kneaded, and then a polyacetal resin (C) is melt-kneaded, or a part thereof is in the form of a block copolymer (D). A method of melt kneading the thermoplastic polyurethane (A), the polymer (B) and the polyacetal resin (C) using the existing thermoplastic polyurethane (A) and the polymer (B) is more preferable. In addition, in mixing each component, a vertical type mixer or a horizontal type mixer which is usually used can be used.
The temperature of the melt-kneading is not particularly limited and may be appropriately set in consideration of the melting temperature, the decomposition temperature and the like of each component, but is usually preferably in the range of 100 to 270 ° C. When the thermoplastic polyurethane (A) is produced by a continuous melt polymerization method using a multi-screw extruder in the substantial absence of a solvent, the polymer (B) having a hydroxyl group at the terminal and the polyacetal resin are used. The resin composition of the present invention can also be produced by feeding (C) into the extruder. Also in this method, similarly to the above, the melt kneading of the thermoplastic polyurethane (A) or the raw material compound (monomer and prepolymer) thereof and the polymer (B) having a hydroxyl group at the terminal precedes, and then the polyacetal resin ( It is preferable to determine the supply positions of the polymer (B) and the resin (C) so that C) is kneaded.

In the resin composition of the present invention, the thermoplastic polyurethane (A) which is not incorporated in the molecule of the block copolymer (D) (hereinafter referred to as "true thermoplastic polyurethane (A ')"). Has an effect of increasing impact resistance and tensile strength / elongation at room temperature, but if too much, the elastic modulus tends to decrease. The polymer (B) which is not incorporated in the molecule of the block copolymer (D) (hereinafter, referred to as “true polymer (B ′)”) has impact resistance, particularly impact resistance at low temperature. , But there is a tendency for the elastic modulus to decrease when the amount is too large. Polyacetal resin (C)
As described above, it has the effect of improving the tensile strength and elongation, but if it is too large, it lowers the impact resistance. Further, the block copolymer (D) has an effect of improving impact resistance, but if it is too much, it tends to reduce melt fluidity, resulting in deterioration of moldability. The block copolymer (D) is a true thermoplastic polyurethane (A ') and a true polymer (B').
And are produced when they are brought into contact with each other in the presence or absence of the polyacetal resin (C) under heating conditions. Therefore, in the mixing operation for producing the resin composition of the present invention, they are separately produced. It is not necessary to use the block copolymer (D), but the thermoplastic polyurethane (A) and the polymer (B), some of which are present in the form of the block copolymer (D), are used. In this case, when the above-mentioned various properties are comprehensively taken into consideration, a true thermoplastic polyurethane (A ′), a true polymer (B ′), a polyacetal resin (C) and a block copolymer (D).
Is (A ') 2-9 based on the sum of these amounts used.
0% by weight, (B ') accounts for 2 to 90% by weight,
(C) accounts for 5 to 95% by weight, and (D) is 1 to 60
It is more preferable to use it in such a proportion that it accounts for 2 to 46.5% by weight of (A '), 2 to 46.5% by weight of (B') and 50 of (C). ~ 95% by weight
Is more preferably used, and (D) is more preferably used in a proportion such that it accounts for 1 to 46% by weight. From the viewpoint of the above-mentioned various properties, the amount of each of the true thermoplastic polyurethane (A ′), the true polymer (B ′) and the block copolymer (D) used is (A ′) / The weight ratio of (B ′) is 2/8 to 8/2, and the weight ratio of [the sum of ((A ′) and (B ′)] / (D) is 4/6 to 9/1. It is preferable that the condition is further satisfied. The block copolymer (D) separately prepared in advance is used together with the true thermoplastic polyurethane (A ′), the true polymer (B ′) and the polyacetal resin (C) to produce the resin composition of the present invention. In the case of using the block copolymer (D)
The structure of the polymer block of may be different from the true thermoplastic polyurethane (A ′) and / or the true polymer (B ′) used.

The block copolymer (D) is obtained by reacting the true thermoplastic polyurethane (A ') with the true polymer (B') under melt-kneading conditions or by heating in a solution. Method to give a true thermoplastic polyurethane (A ') a monomer or prepolymer to give a true polymer (B')
It can be produced by a method such as urethanization reaction (polymerization) in the presence of According to these reactions, the block copolymer (D) is usually obtained in the form of a composition of the true thermoplastic polyurethane (A ′) and the true polymer (B ′). It can be directly used for the production of the resin composition of the present invention without being subjected to a purification operation. Further, the true thermoplastic polyurethane (A ′) is extracted and removed from the composition obtained by the above reaction with a good solvent for the polyurethane such as dimethylformamide,
Since the purity of the block copolymer (D) can be increased by extracting and removing the true polymer (B ′) with a good solvent for the polymer such as cyclohexane, the block thus obtained can be obtained. The copolymer (D) may be used for producing the resin composition of the present invention.

The resin composition of the present invention can be hot-melt molded and heat-processed, and can be molded / processed by any molding method such as injection molding, extrusion molding, blow molding, calender molding and cast molding. is there. Molded articles obtained from the resin composition of the present invention thus obtained include articles of any shape such as film, sheet, tube, and three-dimensional shape. The molded product can be used for a wide variety of uses such as automobile parts, home electric appliance parts, computer parts, machine parts, packing, gaskets, hoses and the like.

[0038]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

In the examples, the tensile strength and elongation of the resin composition, the impact resistance, the surface condition of the molded article and the compatibility were measured or evaluated by the following methods.

[Tensile rupture strength / elongation] Using a dumbbell piece obtained by injection molding of a resin composition, JIS K7
In accordance with 311 the tensile strength and tensile elongation were measured.

[Impact resistance] Using an IZOD (Izod) test piece (with a mold notch) obtained by injection-molding a resin composition, an IZOD impact resistance test was conducted at two points of 25 ° C and -20 ° C. .

[Surface Condition of Molded Article] The surface condition of the test piece of the dumbbell piece obtained by injection-molding the resin composition was observed with the naked eye to determine whether the surface condition was good or not in terms of whether or not peeling occurred on the surface. Was evaluated.

[Compatibility] The fracture surface formed by breaking the test piece of the dumbbell piece under cooling conditions was etched with dimethylformamide, and then the surface near the center of the fracture surface was observed by a scanning electron microscope (SEM). The state of the dispersed particles was evaluated by observing with, and the average dispersed particle diameter was measured.

Reference Example 1 (Synthesis of polymeric diol) 1420 g of 3-methyl-1,5-pentanediol and 1460 g of adipic acid were charged into a reactor, and nitrogen gas was passed through the system under atmospheric pressure at about 220 ° C. The esterification reaction was carried out while distilling the produced water out of the system. When the acid value of the produced polyester diol became 0.3 or less, the degree of vacuum was gradually raised by a vacuum pump to complete the reaction. The obtained polyester diol (hereinafter, PM
The average molecular weight of PA) was 3,500.

Reference Example 2 (Synthesis of Thermoplastic Polyurethane) PMPA, 1,4-butanediol (BD) and 4,4′-diphenylmethane diisocyanate (MDI) produced in Reference Example 1 were mixed with PMPA / BD / MDI in moles. With a metering pump so that the ratio becomes 1 / 3.13 / 4.13 and the total amount of these is 300 g / min,
Twin screw extruder rotating in the same direction (30 mmφ, L / D = 3
6. Cylinder temperature: 75 to 260 ° C.) was continuously supplied to carry out continuous melt polymerization. The resulting polyurethane melt was continuously extruded in water in the form of a strand, cut into pellets with a pelletizer, and dehumidified and dried at 80 ° C. for 20 hours to give a thermoplastic polyurethane (hereinafter, referred to as TPU-
1)).

Reference Example 3 (Synthesis of a Polymer Having a Hydroxyl Group at the Terminal) After a styrene monomer was anionically polymerized in cyclohexane using n-butyllithium as an initiator, an isoprene monomer was added to produce a living block polymer. did. Further, a 10-fold molar amount of ethylene oxide was added to the polymerization active terminal, and then methanol was added to stop the reaction. Thus, a polystyrene-polyisoprene diene block copolymer having a hydroxyl group at the molecular end was obtained. After dissolving the polystyrene-polyisoprene diene block copolymer having a hydroxyl group at the terminal in cyclohexane, Raney nickel catalyst was added to the solution to give 50 kg /
A polystyrene having a hydroxyl group at the terminal of the main chain of the molecule is subjected to a hydrogenation reaction at 150 ° C. under a hydrogen pressure of cm ^2.
Hydrogenated product of polyisoprene diene block copolymer (hereinafter referred to as S
EP-OH) was obtained. Regarding the SEP-OH, the number average molecular weight of the polymer block composed of styrene units was 10,000, and the number average molecular weight of the polymer block mainly composed of hydrogenated isoprene units was 2
The molar ratio of styrene unit / isoprene unit (the total of hydrogenated units and non-hydrogenated units) was 25/75, and the hydroxyl group content was 0 on average per molecule. It was 0.89, and the hydrogenation rate at the carbon-carbon double bond of the isoprene unit was 97%.

Reference Example 4 (Synthesis of Polymer Having No Hydroxyl Group at Terminal) After the production of the living block polymer, the reaction procedure and treatment were carried out in the same manner as in Reference Example 3 except that the reaction was terminated with methanol without adding ethylene oxide. By performing the operation, a hydrogenated product of a polystyrene-polyisoprene diene block copolymer having no hydroxyl group at the terminal (hereinafter, referred to as SEP
).

Reference Example 5 (Synthesis of Block Copolymer from Thermoplastic Polyurethane and Polymer Having Hydroxyl Group at Terminal) TPU-1 produced in Reference Example 2 and S produced in Reference Example 3
EP-OH was pellet-blended at a ratio of TPU-1 / SEP-OH at a weight ratio of 50/50, and then the mixed pellets were melt-kneaded in a twin-screw extruder (cylinder temperature: 220 ° C.). The obtained melt-kneaded product was pulverized with a pulverizer to give a fine powder. Dimethylformamide was added to this powdery substance, and unreacted TPU-1 was extracted by stirring at room temperature for 10 hours, and then the solid substance was separated by filtration.
Then, cyclohexane was added to the obtained powdery solid substance, and unreacted SEP-OH was extracted by stirring at a temperature of 100 ° C. for 10 hours, and then the obtained solid substance was separated by filtration and dried. . From the gel permeation chromatogram and the like, the obtained powdery solid matter shows that the block copolymer (B) has a polymer block corresponding to TPU-1 and a polymer block corresponding to SEP-OH (hydroxyl group is lost). Hereinafter, it will be referred to as SEP-TPU). In addition, SEP-T based on the above melt-kneaded product
The production rate of PU was 43% by weight.

Example 1 A thermoplastic polyurethane (hereinafter, referred to as TPU) was prepared by carrying out continuous melt polymerization using a twin-screw extruder in the same manner as in Reference Example 2.
-2) is produced, and the polymer SEP-OH having a hydroxyl group at the terminal obtained in Reference Example 3 is kneaded with TPU-2 flowing in the twin-screw extruder, and then Polyacetal resin (DuPont Delrin 100P (hereinafter referred to as POM)) is about 200 ° C.
Each of SEP-OH and POM was supplied to a predetermined position of a twin-screw extruder so as to be kneaded. In addition, TPU
-2 / SEP-OH / POM weight ratio is 15/15/7
The supply amount was set to be 0. A melt of the obtained resin composition is continuously extruded in a strand form into water from an extruder, cut into pellets by a pelletizer, and then melted at 80 ° C. for 2 hours.
A resin composition (hereinafter, referred to as resin composition-1) was obtained by dehumidifying and drying for 0 hours. Obtained resin composition-
1 was injection-molded, and the obtained molded product was subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Example 2 TPU-1 obtained in Reference Example 2 and SEP produced in Reference Example 3
-OH and POM, TPU-1 / SEP-OH / P
After pellet blending at a ratio of OM weight ratio of 15/15/70, the pellet mixture was fed to a twin-screw extruder and melt-kneaded at about 200 ° C. A melt of the obtained resin composition is continuously extruded in water in a strand form from an extruder, cut into pellets with a pelletizer, and dehumidified and dried at 80 ° C. for 20 hours to give a resin composition (hereinafter, referred to as resin composition). Product-2). The obtained resin composition-2 was injection-molded, and the obtained molded products were subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Example 3 TPU-1 obtained in Reference Example 2 and SEP produced in Reference Example 3
-OH and TPU-1 / SEP-OH in a weight ratio of 15
After blending the pellets in a ratio of / 15, the mixed pellets are twin-screw extruder (cylinder temperature: 70 to 260 ° C).
Melt kneading was performed in the above to obtain a melt kneaded product of TPU-1 and SEP-OH. The obtained melt-kneaded product was continuously extruded in water in a strand form from an extruder, cut into pellets with a pelletizer, and dried at 80 ° C. for 20 hours in a dehumidified state. The pelletized melt-kneaded product and POM were fed to a twin-screw extruder at a ratio of the melt-kneaded product / POM weight ratio of 30/70,
Melt kneading was performed at a temperature of about 200 ° C. A melt of the obtained resin composition is continuously extruded in a strand form into water from an extruder, cut into pellets by a pelletizer, and then melted at 80 ° C. for 2 hours.
A resin composition (hereinafter referred to as resin composition-3) was obtained by dehumidifying and drying for 0 hours. Obtained resin composition-
Injection molding was performed on No. 3, and the obtained molded products were subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Example 4 In the same manner as in Reference Example 5, TPU-1 and SEP-OH were melt-kneaded using a twin-screw extruder and then extruded and cut to obtain a pelletized composition (containing TPU-1 / SE
Weight ratio of P-OH / SEP-TPU: 4/4/6) 1
4 parts by weight were pellet blended with 70 parts by weight POM, 8 parts by weight TPU-1 and 8 parts by weight SEP-OH. The resulting pellet mixture (TPU-1 / SEP-O
Weight ratio of H / POM / SEP-TPU: 12/12/7
0/6) was fed to a twin-screw extruder and melt-kneaded at about 200 ° C. A melt of the obtained resin composition is continuously extruded in water in a strand form from an extruder, cut into pellets with a pelletizer, and dehumidified and dried at 80 ° C. for 20 hours to give a resin composition (hereinafter, referred to as resin composition). Product-4). Injection molding is performed on the obtained resin composition-4,
The obtained molded product was subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Example 5 6 parts by weight of the SEP-TPU obtained in Reference Example 5 was added to PO.
70 parts by weight of M, 12 parts by weight of TPU-1 and SEP
Pellets were blended with 12 parts by weight of -OH, and the obtained pellet mixture was fed to a twin-screw extruder and melt-kneaded at about 200 ° C. A melt of the obtained resin composition is continuously extruded in water in a strand form from an extruder, cut into pellets with a pelletizer, and dehumidified and dried at 80 ° C. for 20 hours to give a resin composition (hereinafter, referred to as resin composition). (Item-5)
I got The obtained resin composition-5 was injection-molded, and the obtained molded products were subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Comparative Example 1 A treatment was carried out in the same manner as in Example 3 except that the same weight of SEP was used instead of SEP-OH, and the corresponding resin composition (hereinafter referred to as resin composition-6) was obtained. Obtained. The obtained resin composition-6 was injection-molded, and the obtained molded products were subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Comparative Example 2 The melt-kneaded product / POM weight ratio was 30/70 to 2/98.
A treatment was performed in the same manner as in Example 3 except that the above was changed to, to obtain a corresponding resin composition (hereinafter referred to as resin composition-7). The obtained resin composition-7 was injection-molded, and the obtained molded products were subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Comparative Example 3 POM was directly injection-molded and the resulting molded product was subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Comparative Example 4 TPU-1 and POM without using SEP-OH at all
Was treated in the same manner as in Example 2 except that only TPU-1 / POM was used in a weight ratio of 15/70 to obtain a resin composition (hereinafter, referred to as resin composition-8). . The obtained resin composition-8 was injection-molded,
The obtained molded product was subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

Comparative Example 5 SEP-OH and POM without using TPU-1 at all
Was treated in the same manner as in Example 2 except that only SEP-OH / POM was used in a weight ratio of 15/70 to obtain a resin composition (hereinafter, referred to as resin composition-9). . The obtained resin composition-9 was subjected to injection molding,
The obtained molded product was subjected to various evaluations. The obtained evaluation results are shown in Table 1 below.

[0059]

[Table 1]

From Table 1 above, the resin compositions according to the present invention obtained in Examples 1 to 5 are excellent in tensile strength and elongation, impact resistance at room temperature and low temperature, and molding processability. I understand. On the other hand, when a polymer having the same structure except that it does not have a hydroxyl group at the end was used instead of the polymer having a hydroxyl group at the end (Comparative Example 1), tensile strength, impact resistance, and molding Insufficient properties, etc .; when the thermoplastic polyurethane (A) and the polymer having a hydroxyl group at the end (B) are contained in very small amounts or do not contain them at all (Comparative Examples 2 and 3), room temperature and low temperature are used. In the case where the polymer (B) having a hydroxyl group at the terminal is not contained (Comparative Example 4),
Insufficient impact resistance, especially impact resistance at low temperature; and in case of not containing thermoplastic polyurethane (A) (Comparative Example 5), tensile elongation, impact resistance at room temperature and molding. It can be seen that the workability is insufficient. Among the resin compositions according to the present invention, the thermoplastic polyurethane (A)
In the case where the polyacetal resin (C) is melt-kneaded after melt-kneading the polymer with a hydroxyl group-terminated polymer (B) (Examples 1 and 3), and the thermoplastic polyurethane (A)
And a polymer (B), a part of which is present in the form of a block copolymer (D), and this is melt-kneaded with the polyacetal resin (C) (Example 4).
It can be seen that and 5) are particularly excellent in tensile elongation, impact resistance at room temperature and low temperature, and the like.

[0061]

The resin composition of the present invention is excellent in tensile strength / elongation, impact resistance at room temperature and low temperature, and molding processability. In addition, the molded article of the present invention effectively exhibits these excellent properties.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Kanao 1621 Sakata, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd. (72) Inventor Shunji Kanada 1621 Sakata, Kurashiki City, Okayama Prefecture Kuraray Co., Ltd. (72) Invention Norihiro Nakata 36 Towada, Kamisu-cho, Kashima-gun, Ibaraki Prefecture Kuraray Co., Ltd.

Claims (8)

[Claims] (1) Thermoplastic polyurethane (A); the molecular main chain is mainly composed of an optionally hydrogenated conjugated diene compound unit (I) and an aromatic vinyl compound unit (II), and a unit ( The molar ratio of I) / unit (II) is 1
It contains a polymer (B) having a hydroxyl group at the terminal of the molecular main chain in the range of 0/90 to 90/10; and a polyacetal resin (C) (provided that at least one of the thermoplastic polyurethane (A) is Part and at least a part of the polymer (B) are in the form of a block copolymer (D) which can be formed by a chemical reaction with the thermoplastic polyurethane (A) at the position of the terminal hydroxyl group of the polymer (B). And (2) based on the total weight of (A), (B) and (C) above, the proportion of (A) is 2.5 to 90% by weight, and (B) Is 2.5 to 90% by weight, and (C)
The resin composition has a ratio of 5 to 95% by weight. 2. The resin composition according to claim 1, which is obtained by kneading the thermoplastic polyurethane (A), the polymer having a hydroxyl group at the terminal (B) and the polyacetal resin (C) under melting conditions. 3. A thermoplastic polyurethane (A) and a polymer (B) having a hydroxyl group at the terminal are melt-kneaded, and then a polyacetal resin (C) is melt-kneaded.
The resin composition as described in the above. 4. The thermoplastic polyurethane (A) used and a part of the polymer (B) having a hydroxyl group at the terminal are in the form of a block copolymer (D). Resin composition. 5. The average hydroxyl group content of the polymer (B) having a hydroxyl group at the end is 0.5 to 0.5.
It is two pieces, The resin composition of any one of Claims 1-4. 6. The polymer (B) having a hydroxyl group at the terminal,
It has a main chain structure of a block copolymer containing at least one polymer block mainly composed of a unit (I) and at least one polymer block mainly composed of an aromatic vinyl compound unit (II). The resin composition according to any one of claims 1 to 5. 7. The thermoplastic polyurethane (A) comprises a high molecular diol having a number average molecular weight of 1,500 to 6,000, an organic diisocyanate and a chain extender, represented by the following mathematical formula: 0.9 ≦ b / ( a + c) ≦ 1.1 (in the formula, a represents the number of moles of the polymer diol, b represents the number of moles of the organic diisocyanate, and c represents the number of moles of the chain extender). The resin composition according to any one of claims 1 to 6, which is the obtained thermoplastic polyurethane. 8. A molded article made of the resin composition according to claim 1.