CN109385036A

CN109385036A - Polyoxymethylene resin composition and formed body

Info

Publication number: CN109385036A
Application number: CN201810872437.2A
Authority: CN
Inventors: 都筑隼; 都筑隼一; 鹿野泰和
Original assignee: Asahi Kasei Kogyo KK
Current assignee: Asahi Kasei Corp
Priority date: 2017-08-03
Filing date: 2018-08-02
Publication date: 2019-02-26
Anticipated expiration: 2038-08-02
Also published as: CN109385036B; JP2019026810A; JP6938266B2

Abstract

The present invention relates to polyoxymethylene resin composition and formed bodys.The present invention provides a kind of polyoxymethylene resin composition, impact resistance, rigidity, excellent in sliding property, and stability when heat retention is also excellent.A kind of polyoxymethylene resin composition, it is characterized in that, the polyoxymethylene resin composition contains 100 mass parts of (A) acetal resin and (B) modified material 0.5 mass parts~50 mass parts, (B) modified material includes (b-1) thermoplastic polyurethane and (b-2) graft rubber copolymer, and (b-2) graft rubber copolymer has 2 layers or more of structure.

Description

Polyoxymethylene resin composition and formed body

Technical field

The present invention relates to polyoxymethylene resin composition and formed bodys.

Background technique

The mechanical strength of acetal resin, chemical-resistant, sliding property, wear resistance balancing good, and can be easy Ground processing.Therefore, acetal resin is as one of representative engineering plastics, be widely used for electrical equipment mechanism part, Automobile component and other components etc..

In addition, in many potentialities on the way, the market for being improved impact strength is wanted for acetal resin It asks.Moreover, disclosing the various skills by the way that specific components matching to be improved to impact strength in resins such as acetal resins Art.

As such technology for improving impact strength, a kind of hollow molded article of resin is disclosed in patent document 1, It is obtained and core-shell polymer and/or thermoplastic polyurethane resin are matched with acetal resin.In addition, patent document 2 In disclose a kind of composition, it includes the brittle plastics such as polystyrene and rubber compositions.In addition, being disclosed in patent document 3 A kind of composition, the caoutchouc elasticity grafting it includes acetal resin, based on poly- (methyl) acrylate or silicon rubber Polymer and polymer.In addition, disclosing a kind of composition in patent document 4, it includes acetal resin and thermoplastics Property polyurethane resin and/or hud polymerization species impact resistance modifying agent.

Existing technical literature

Patent document

Patent document 1: Japanese Unexamined Patent Publication 7-195496 bulletin

Patent document 2: No. 3929896 bulletins of Japanese Patent No.

Patent document 3: Japanese Unexamined Patent Publication 6-57097 bulletin

Patent document 4: Japanese Unexamined Patent Publication 7-126483 bulletin

Summary of the invention

Problems to be solved by the invention

But the technology recorded in patent document 1 is to be blow-molding as the main starting point.In addition, in patent document 1 In, although disclosing and having used the embodiment of the composition of thermoplastic polyurethane resin and core-shell polymer, the combination Object in terms of the rigidity of material, in the heat retention in molding machine etc. when stability in terms of have room for improvement.

In addition, not disclosing polyoxymethylene resin composition in patent document 2, the composition recorded in patent document 2 is being made For project specific to polyoxymethylene resin composition heat retention when stability in terms of have room for improvement.

In addition, the composition recorded in patent document 3 is in terms of taking into account impact resistance and rigidity, the heat in molding machine etc. There is room for improvement in terms of stability when delay, in terms of sliding properties.

In addition, the technology recorded in the patent document 4 also stability side in sliding property, heat retention in molding machine etc. There is room for improvement in face.

As a result, it is above-mentioned in the prior art, for impact resistance relevant to acetal resin, rigidity, sliding property, heat Stability when delay has room for improvement, it is expected that further improving.

Therefore, the purpose of the present invention is to provide a kind of impact resistance, rigidity, excellent in sliding property, and steady when heat retention Qualitative also excellent polyoxymethylene resin composition.In addition, the purpose of the present invention is to provide a kind of impact resistance, rigidity, slidings Property is excellent, and the also excellent formed body of stability when heat retention.

Means for solving the problems

The inventors of the present invention have made intensive studies in order to solve the above problems, as a result, it has been found that, by will specifically be modified Material is combined with regulation ratio and is contained in acetal resin, be can solve the above subject, has been finally completed the present invention.

That is, the present invention is as described below.

[1] a kind of polyoxymethylene resin composition, which is characterized in that

The polyoxymethylene resin composition contains 0.5 mass parts of 100 mass parts of (A) acetal resin and (B) modified material ~50 mass parts,

(B) modified material includes (b-1) thermoplastic polyurethane and (b-2) graft rubber copolymer, and

(b-2) graft rubber copolymer has 2 layers or more of structure.

[2] polyoxymethylene resin composition as described in project [1], wherein the ICP- of (b-2) graft rubber copolymer The amount of Si element in MS analysis is 1 mass of mass %~25 %.

[3] polyoxymethylene resin composition as described in project [1] or [2], wherein (b-1) thermoplastic polyurethane is Ester type polyurethane.

[4] polyoxymethylene resin composition as described in project [3], wherein in the ester type polyurethane, by isocyanates at The ratio (molar ratio) of ester ingredient when being divided into 1 is 4~5, and the ratio (molar ratio) of polyol component is 5~6.

[5] polyoxymethylene resin composition as described in project [3] or [4], wherein the ester type polyurethane includes more than 2 kinds First alcohol component.

[6] polyoxymethylene resin composition as described in any one of project [1]~[5], wherein (b-2) is grafted rubber Glue copolymer includes polysiloxanes/acrylic polymer, and in the ICP-MS analysis of (b-2) graft rubber copolymer The amount of Si element is 2 mass of mass %~10 %.

[7] polyoxymethylene resin composition as described in any one of project [1]~[6], wherein the acetal resin group The concentration for closing the sulfate ion in object is 0.01ppm~0.2ppm.

[8] polyoxymethylene resin composition as described in any one of project [1]~[7], wherein (A) the polyformaldehyde tree The melt flow rate (MFR) of rouge is 0.1g/10 minutes~60g/10 minutes.

[9] polyoxymethylene resin composition as described in any one of project [1]~[8], wherein the acetal resin group Conjunction object is grain shape.

[10] a kind of formed body, which is characterized in that the formed body includes poly- described in any one of project [1]~[9] Aldehyde resin composition.

Invention effect

In accordance with the invention it is possible to provide a kind of impact resistance, rigidity, excellent in sliding property, and stability when heat retention Excellent polyoxymethylene resin composition.In addition, the present invention is capable of providing a kind of impact resistance, rigidity, excellent in sliding property, and heat stagnation Stability when staying also excellent formed body.

Specific embodiment

Hereinafter, a specific embodiment of the invention (hereinafter referred to as " present embodiment ") is described in detail, but this hair Bright record not limited to the following can carry out various modifications within its scope and implement.

(polyoxymethylene resin composition)

The polyoxymethylene resin composition of present embodiment is characterized in that, contain 100 mass parts of (A) acetal resin, 0.5 mass parts of (B) modified material~50 mass parts, above-mentioned (B) modified material include (b-1) thermoplastic polyurethane and (b- 2) graft rubber copolymer, above-mentioned (b-2) graft rubber copolymer have 2 layers or more of structure.In addition, present embodiment is poly- Aldehyde resin composition can also contain (C) colorant, other additives as optional component.

Hereinafter, being described in detail to each ingredient for the polyoxymethylene resin composition for constituting present embodiment.

< (A) acetal resin >

(in the present specification, sometimes to (A) acetal resin contained by the polyoxymethylene resin composition of present embodiment It is recorded as (A) ingredient or (A) etc.；Hereinafter, also identical about (B) ingredient, (b-1) ingredient, (b-2) ingredient, (C) ingredient) in detail Ground is illustrated.

For (A) acetal resin that can be used in the present embodiment, can enumerate POM-H Acetal homopolymer with And polyacetal copolymer.

Specifically, can be enumerated for as POM-H Acetal homopolymer: by by the trimer of formaldehyde monomers or formaldehyde (threeAlkane) or tetramer (fourAlkane) etc. obtained from the cyclic oligomer homopolymerization of formaldehyde, substantially only include Oxymethylene list The POM-H Acetal homopolymer of member.

In addition, specifically, can be enumerated for as polyacetal copolymer: by making formaldehyde monomers or formaldehyde Trimer (threeAlkane) or tetramer (fourAlkane) etc. the cyclic oligomer of formaldehyde and cyclic ether or ring-type as comonomer Polyacetal copolymer obtained from formal copolymerization.Here, can be enumerated: epoxy for as cyclic ether or cyclic formals The cyclic annular contracting of the glycol such as ethane, propylene oxide, epichlorohydrin, 1,3- dioxolane, 1,4- butylene glycol formal or diethylene glycol (DEG) Formaldehyde；Deng.

Using threeAlkane and in the case where obtaining polyacetal copolymer, be copolymerized about above-mentioned 1,3- dioxolane etc. The usage amount of monomer, it is however generally that, relative to threeAlkane 100mol is preferably 0.1mol~60mol, and more preferably 0.1mol~ 20mol, further preferably 0.13mol~10mol.In addition, in the present embodiment, the fusing point of polyacetal copolymer is preferably 162 DEG C~173 DEG C, more preferably 167 DEG C~173 DEG C, further preferably 167 DEG C~171 DEG C.Fusing point is 162 DEG C~173 DEG C Polyacetal copolymer can be by using relative to threeAlkane 100mol be about 1.3mol~about 3.5mol comonomer and It obtains.It is measured it should be noted that fusing point can use DSC.

In addition, can also be enumerated for as polyacetal copolymer: by making the monomer of formaldehyde and/or the ring-type of formaldehyde Obtained from oligomer and the copolymerization of the monofunctional glycidyl base ether, polyacetal copolymer with branch, and by making formaldehyde Monomer and/or formaldehyde cyclic oligomer and the copolymerization of multifunctional glycidyl ether obtained from, it is poly- with cross-linked structure Copolyoxymethylenes etc..

In addition, (A) acetal resin also may include: having the variety classes different from the constitutional repeating unit of polyformaldehyde Block section block copolymer.

In the case where (A) acetal resin includes block copolymer, can be selected in its different types of block section Property and steadily there is (B) modified material contained by the polyoxymethylene resin composition of present embodiment.Thus, it is possible to table Reveal more stable wear resistance.

For block copolymer said here, it is however preferred to have by any one of the following general formula (1)~(4) table The two (is also denoted as by the POM-H Acetal homopolymer or polyacetal copolymer of at least one of the block section shown together below " block copolymer ").

In above-mentioned general formula (1), (2) and (3), R₁And R₂It each independently represents selected from by hydrogen atom, alkyl, substitution 1 kind of chemical species in group that alkyl, aryl and substituted aryl are constituted, R₁And R₂It, respectively can phase in the case where multiple It is same to can also be different.

In above-mentioned general formula (1), (2) and (4), R₃、R₅、R₆It indicates selected from by alkyl, substitution alkyl, aryl and substitution 1 kind of chemical species in group that aryl is constituted.

In above-mentioned general formula (4), R₄It indicates to be selected from by hydrogen atom, alkyl, alkyl, aryl and substituted aryl replaced to constitute 1 kind of chemical species in group, R₄In the case where multiple, respectively it can be the same or different.

In above-mentioned general formula (1), (2) and (3), m indicates 2~6 integer, preferably 2~4 integer.

In above-mentioned general formula (1), (2) and (3), n indicates 1~1000 integer, preferably 10~250 integer.

In above-mentioned general formula (4), p indicates 2~6 integer, 2 p respectively can it is identical can also be different.

In above-mentioned general formula (4), q, r respectively indicate positive numerical value, and relative to the 100 moles of % that add up to of q and r, q rubs for 2 You are %~100 mole %, and r is 0 mole of %~98 mole % ,-(CH (CH₂CH₃)CH₂)-unit and-(CH₂CH₂CH₂CH₂)- Unit respectively exists in the form of random or block.

It is to slough hydrogen atom from alcohol (poly-) alkylene oxide adduct and obtain by the group that above-mentioned general formula (1) indicates The residue arrived is to slough hydrogen atom from carboxylic acid (poly-) alkylene oxide adduct by the group that above-mentioned general formula (2) indicate Obtained from residue, as above-mentioned general formula (3) indicate group be to be sloughed obtained from hydrogen atom from (poly-) alkylene oxide Residue.

Block copolymer with above-mentioned block section can for example refer to Japanese Unexamined Patent Application 57-31918 bulletin, Japan Tekiaki 60-170652 bulletin, Japanese Unexamined Patent Publication 2002-3696 bulletin, Japanese Unexamined Patent Publication 2002-234922 bulletin, Japan The method recorded in special open 2002-3694 bulletin etc. and prepared.

The block section of the block copolymer indicated by these formula (1)~(4) can obtain in the following way: make two End or single end have the compound of the composition block of the functional groups such as hydroxyl in the polymerization process of acetal resin with end It is reacted part.

The insertion of the block section indicated by above-mentioned formula (1)~(4) in block copolymer is not particularly limited, will be embedding The ratio of above-mentioned block section when section copolymer is set as 100 mass % is preferably 0.001 mass of mass %~30 %.By upper The ratio stated is 0.001 mass % or more, sliding property steadily can be persistently maintained, in addition, by being 30 mass % hereinafter, can To inhibit the reduction of the rigidity of the formed body of the polyoxymethylene resin composition comprising present embodiment.From the same viewpoint, Above-mentioned ratio is more preferably 0.01 mass % or more, further preferably 0.1 mass % or more, is still more preferably 1 matter % or more is measured, in addition, more preferably 15 mass % are hereinafter, further preferably 8 mass % or less.

In addition, the molecular weight about the block section in block copolymer, never reduces the poly- first comprising present embodiment From the viewpoint of the rigidity of the formed body of urea formaldehyde composition, preferably 10000 hereinafter, more preferably 8000 hereinafter, further Preferably 5000 or less.On the other hand, the lower limit of the molecular weight of the block section in block copolymer is not particularly limited, from holding From the viewpoint of the stable sliding property of continuous maintenance, preferably 100 or more.

The compound of the block section formed in block copolymer is not particularly limited, such as can enumerate: C₁₈H₃₇O (CH₂CH₂O)₄₀C₁₈H₃₇、C₁₁H₂₃CO₂(CH₂CH₂O)₃₀H、C₁₈H₃₇O(CH₂CH₂O)₇₀H、C₁₈H₃₇O(CH₂CH₂O)₄₀Or two ends H, It is the polypropylene glycol of hydroxyl for the polyethylene glycol of hydroxyl, two ends, two ends are the hydrogenated butadiene polymer of hydroxyl, two terminal hydroxyls Alkyl polyethylene glycol, two terminal hydroxyls alkylation polypropylene glycol, two terminal hydroxyls are alkylated hydrogenated butadiene polymer, glycidol Based compound (simple function, multifunctional) etc..

Polymerization catalyst used in the polymerization of polyacetal copolymer is not particularly limited, for example, preferably lewis acid, The cationic active catalysts such as Bronsted acid and its ester or acid anhydrides.Lewis acid is not particularly limited, for example, can enumerate boric acid, Tin, titanium, phosphorus, arsenic and antimony halide more specifically can enumerate boron trifluoride, tin tetrachloride, titanium tetrachloride, five fluorine Change phosphorus, phosphorus pentachloride, antimony pentafluoride and its complex compound or salt.In addition, Bronsted acid and its ester or acid anhydrides are not particularly limited, Such as perchloric acid, trifluoromethanesulfonic acid, the perchloric acid tert-butyl ester, acetylperchlorate, trimethyl oxygen can be enumeratedHexafluorophosphate. Among them, for polymerization catalyst, preferably boron trifluoride, boron trifluoride hydrate and former containing oxygen atom or sulphur More specifically the organic compound of son and the co-ordination complex of boron trifluoride can enumerate boron trifluoride Anaesthetie Ether, trifluoro Change boron di-n-butyl ether as preference.

The manufacturing method of polyacetal copolymer is not particularly limited, and conventionally known method can be used, such as can arrange It lifts No. 3027352 specifications of U.S. Patent No., No. 3803094 specifications of U.S. Patent No., Deutsche Bundespatent and invents No. 1161421 Specification, Deutsche Bundespatent invent No. 1495228 specification, Deutsche Bundespatent invents No. 1720358 specification, Deutsche Bundespatent hair It is recorded in bright No. 3018898 specification, Japanese Unexamined Patent Application 58-98322 bulletin and Japanese Unexamined Patent Publication 7-70267 bulletin Method.In addition, about the polyacetal copolymer as obtained from the above method, due to there are the terminal part of thermally labile [- (OCH₂)_n- OH group], therefore the decomposition removal processing of unstable terminal part is preferably implemented.

Specifically, in the decomposition removal processing of unstable terminal part, at least one kind of season indicated by following formula (5) In the presence of ammonium compounds, more than the fusing point of polyacetal copolymer and at 260 DEG C of temperature below, make polyacetal copolymer Implement heat treatment in the state of melting.

[R^aR^bR^cR^dN⁺]_n’X^-n’···(5)

Here, in formula (5), R^a、R^b、R^cAnd R^dEach independently represent the substituted or unsubstituted of carbon atom number 1~30 Alkyl, the aryl of carbon atom number 6~20, at least one hydrogen atom quilt in the substituted or unsubstituted alkyl of carbon atom number 1~30 At least one hydrogen in aralkyl obtained from the aryl of carbon atom number 6~20 replaces or the aryl of carbon atom number 6~20 is former Alkylaryl obtained from son is replaced by the substituted or unsubstituted alkyl of carbon atom number 1~30；Substituted or unsubstituted alkyl For straight-chain, branch-like or ring-type.Substituent group in above-mentioned substitution alkyl be halogen atom, hydroxyl, aldehyde radical, carboxyl, amino, Or amide groups.In addition, hydrogen atom can also be by halogen original in above-mentioned unsubstituted alkyl, aryl, aralkyl, alkylaryl Son replaces.N ' indicates 1~3 integer.X indicate the carboxylic acid of hydroxyl or carbon atom number 1~20, the hydracid other than hydrogen halides, The sour residue of organic thio-acid of oxyacid, inorganic thio-acid or carbon atom number 1~20.

Quaternary ammonium compound is then not particularly limited if it is the quaternary ammonium compound indicated by above-mentioned formula (5), but from more having R from the viewpoint of the said effect for imitating and being reliably achieved present embodiment, in formula (5)^a、R^b、R^cAnd R^dEach independently The preferably alkyl of carbon atom number 1~5 or the hydroxy alkyl of carbon atom number 2~4, further, particularly preferred R^a、R^b、R^cAnd R^dIn at least one be ethoxy.Such quaternary ammonium compound is not particularly limited, and can specifically enumerate: tetramethyl-ammonium, Tetraethyl ammonium, tetrapropyl ammonium, tetra-n-butyl ammonium, cetyltrimethylammonium ammonium, ammonium, 1,6- hexamethylene bis (trimethyl ammonium), decamethylene bis- (trimethyl ammoniums), trimethyl -3- chlorine-2-hydroxyl propyl ammonium, trimethyl (2- ethoxy) ammonium, Triethyl group (2- ethoxy) ammonium, tripropyl (2- ethoxy) ammonium, three normal-butyls (2- ethoxy) ammonium, tri methyl benzyl ammonium, three second Base hexadecyldimethyl benzyl ammonium, tripropyl hexadecyldimethyl benzyl ammonium, three normal-butyl hexadecyldimethyl benzyl ammoniums, trimethylphenyl ammonium, triethyl group phenyl ammonium, trimethyl -2- hydroxyl Ethyl ammonium, monomethyl trihydroxyethyl ammonium, Dan Yiji trihydroxyethyl ammonium, octadecyl three (2- ethoxy) ammonium, four (ethoxy) ammoniums Deng hydroxide；The hydrohalogenic acid salts such as hydrochloric acid, hydrobromic acid, the hydrofluoric acid of above-mentioned quaternary ammonium compound；The sulfuric acid of above-mentioned quaternary ammonium compound, Nitric acid, phosphoric acid, carbonic acid, boric acid, chloric acid, acid iodide, silicic acid, perchloric acid, chlorous acid, hypochlorous acid, sulfuric chlorohydrin, sulfamic acid, burnt sulphur The oxysalts such as acid, tripolyphosphate；The thiosalts such as the thiosulfuric acid of above-mentioned quaternary ammonium compound；The first of above-mentioned quaternary ammonium compound The carboxylates such as acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, octanoic acid, capric acid, benzoic acid, oxalic acid.It is excellent among them Choose the hydroxide (OH for stating quaternary ammonium compound^-), sulfuric acid (HSO₄ ^-、SO₄ ^2-), carbonic acid (HCO₃ ^-、CO₃ ^2-), boric acid (B (OH)₄ ^-) And the salt of carboxylic acid.Among carboxylic acid, particularly preferred formic acid, acetic acid, propionic acid.Quaternary ammonium compound can be used alone, can also Two or more is applied in combination.Alternatively, it is also possible to together and be used as well known unstable terminal part with above-mentioned quaternary ammonium compound The amines such as ammonia, the triethylamine of decomposition accelerating agent.

The usage amount of quaternary ammonium compound be scaled total quality relative to polyacetal copolymer and quaternary ammonium compound, by The nitrogen quantity from quaternary ammonium compound that following formula (6) indicates is preferably the 0.05 mass ppm of mass ppm~50, more preferably 1 mass The mass of ppm~30 ppm.

Usage amount=P × 14/Q (6) of quaternary ammonium compound

Here, P indicates the concentration (quality ppm) relative to polyacetal copolymer of quaternary ammonium compound, and 14 are in formula (6) The atomic weight of nitrogen, Q indicate the molecular weight of quaternary ammonium compound.

Usage amount by quaternary ammonium compound is 0.05 mass ppm or more, and the decomposition removal speed of unstable terminal part has The tendency further increased.In addition, by for 50 mass ppm hereinafter, unstable terminal part decompose removal after polyformaldehyde be copolymerized The tone of object tends to more excellent.

About the unstable terminal part of the acetal resin in present embodiment, more than fusing point and 260 DEG C of temperature below When being heat-treated in the state of melting polyacetal copolymer under degree, removal can be decomposed.Make in decomposition removal processing Device is not particularly limited, preferably extruder, kneader etc..The formaldehyde generated by decomposition is usually gone under reduced pressure It removes.The method that quaternary ammonium compound is mixed with polyacetal copolymer is not particularly limited, such as can be enumerated: make it is polymerization catalyzed It is blown by method that quaternary ammonium compound adds in form of an aqueous solutions, by quaternary ammonium compound to passing through polymerization in the process of agent inactivation And the method for the polyacetal copolymer powder generated.No matter any method is used, as long as adding to polyacetal copolymer There are quaternary ammonium compounds in the copolymer in the process of heat treatment.For example, it is also possible to which quaternary ammonium compound is injected into Polyacetal copolymer is carried out among melting mixing and the extruder of extrusion.Alternatively, using the extruder etc., by filler, face In the case that material is matched with polyacetal copolymer, quaternary ammonium compound can also be added to the resin of polyacetal copolymer first Grain, filler behind, pigment cooperation when carry out the decomposition removal processing of unstable terminal part.

The decomposition removal processing of unstable terminal part can also make to be total to the polyacetal copolymer as obtained from polymerizeing Deposit polymerization catalyst inactivation after carry out, alternatively, it is also possible to do not make polymerization catalyst inactivate in the case where carry out.It is urged as polymerization For the inactivation processing of agent, it can enumerate the method in polymerization catalyst with inactivation in the alkaline aqueous solution of amine etc.. In the case where the inactivation without polymerization catalyst, in non-active gas at the fusing point temperature below of polyacetal copolymer Polyacetal copolymer is heated under atmosphere, polymerization catalyst is reduced by volatilization, then carries out unstable terminal part Decomposition remove operation, this is also effective.

By the decomposition removal processing of unstable terminal part as described above, very excellent poly- of thermal stability can be obtained Copolyoxymethylenes.

About (A) acetal resin for constituting polyoxymethylene resin composition, the terminal part of total end number relative to molecule OH base unit weight be preferably 5%~95%.If the OH base unit weight of terminal part be 95% hereinafter, if can be in the manufacture of resin combination When intentionally formed slight void (ミ Network ロボイ De), therefore preferably, in addition, if the OH base unit weight of terminal part be 5% or more, The adhesiveness of (B) modified material then can be improved.From the same viewpoint, the OH base unit weight of terminal part be more preferably 90% with Under, further preferably 85% hereinafter, be still more preferably 80% hereinafter, in addition, more preferably 6% or more, further excellent It is selected as 7% or more, is still more preferably 10% or more.

Constitute polyoxymethylene resin composition the preferred terminal part of (A) acetal resin OH base unit weight be 10mmol/kg~ 200mmol/kg.If the OH base unit weight of terminal part be 200mmol/kg hereinafter, if the heat of polyoxymethylene resin composition can be made steady It is qualitative very excellent during fabrication, in addition, the crystallinity of acetal resin tends to rise up if it is 10mmol/kg or more, It is preferred.From the same viewpoint, the OH base unit weight of terminal part is more preferably 150mmol/kg hereinafter, further preferably 100mmol/kg is hereinafter, be still more preferably 90mmol/kg hereinafter, in addition, more preferably 15mmol/kg or more, further Preferably 20mmol/kg or more is still more preferably 40mmol/kg or more.

It should be noted that the OH base unit weight of terminal part passes through utilization¹H-NMR and¹³C-NMR etc. is directly as well as indirectly surveyed It is fixed.

Method not limited to the following is directly measured, can be passed through¹H-NMR and¹³The two-dimentional NMRs such as C-NMR, presaturation method, WET method etc. is directly observed.

Indirect determination method not limited to the following, (A) acetal resin can be dissolved in NMR measurement solvent then to be made Derivative materialization is carried out with the silylating agent etc. that can be reacted with the OH base of terminal part, is then measured.

Silylating agent is not limited to following compound, and hexamethyldisilazane, dimethyldichlorosilane, three can be used Methylchlorosilane, trim,ethylchlorosilane, N, bis- (trimethyl silyl) acetamides of O-, N- methyl-N- trimethyl silyl Acetamide, N- methyl-N- trimethyl silyl trifluoroacetamide, N- trimethyl silyl dimethyl amine, N- trimethyl first Silylation diethylamide, N, bis- (trimethyl silyl) trifluoroacetamides of O-, N- trimethyl-silyl-imidazole, tert-butyl two Methylchlorosilane, N- methyl-N- t-butyldimethylsilyl trifluoroacetamide etc..

For (A) acetal resin as the polyoxymethylene resin composition for constituting present embodiment, poly- first can be used Aldehyde homopolymer, the polyacetal copolymer with branch, the polyacetal copolymer with cross-linked structure, has polyacetal copolymer In the block copolymer based on homopolymer and the block copolymer based on copolymer with block section of block section Any one, they can also be used in combination.

In addition, as (A) acetal resin, such as can also be suitable for using the different combination of molecular weight, amount of comonomers The combination etc. of different polyacetal copolymers.

It should be noted that copolymer, block in the formed body of the polyoxymethylene resin composition comprising present embodiment The ratio of copolymer can pass through¹H-NMR and¹³C-NMR etc. is measured.

In addition, the structure of block section can be determined as follows: by the acetal resin containing block copolymer Composition or formed body dissolution comprising the polyoxymethylene resin composition, carry out reprecipitation, the operation such as filtering is simultaneously separated, so Hydrochloric acid decomposition is carried out to the block copolymer afterwards, thus, it is possible to isolate and purify block section, by carrying out to the block section¹H-NMR、¹³The various measurements such as C-NMR, two-dimentional NMR, so can determine that the structure of block section.

(A) melt flow rate (MFR) of acetal resin is not particularly limited, the melt measured according to ISO-1133 condition D Flow rate is preferably 0.1g/10 minutes~60g/10 minutes.By melt flow rate (MFR) be 0.1g/10 minutes or more, from Preferred from the aspect of type mobility, in addition, by for 60g/10 minutes hereinafter, impact strength can be further increased.This Outside, if melt flow rate (MFR) within the above range, can be in the polyoxymethylene resin composition of present embodiment equably Disperse (B) modified material.From the same viewpoint, the melt flow rate (MFR) of (A) acetal resin is more preferably 50g/10 points Clock hereinafter, further preferably 20g/10 minutes hereinafter, still more preferably for 10g/10 minutes hereinafter, particularly preferably 5g/ 10 minutes or less.On the other hand, from the same viewpoint, the melt flow rate (MFR) of (A) acetal resin is more preferably 0.2g/ 10 minutes or more, further preferably 0.5g/10 minutes or more are still more preferably 1g/10 minutes or more, particularly preferably 2g/10 minutes or more.

(A) melt viscosity of acetal resin is not particularly limited.For example, shearing speed of (A) acetal resin at 190 DEG C Rate 100s^-1When viscosity be preferably 100Pas~4000Pas.It, can be in this reality if the viscosity is within the above range Applying in the polyoxymethylene resin composition of mode is uniformly dispersed (B) modified material.In addition, (A) acetal resin is at 190 DEG C Shear rate 100s^-1When viscosity be more preferably 3000Pas hereinafter, further preferably 2000Pas hereinafter, further Preferably 1500Pas is hereinafter, particularly preferably 1000Pas or less.On the other hand, (A) acetal resin is cut at 190 DEG C Cutting speed rate 100s^-1When viscosity be more preferably 150Pas or more, further preferably 200Pas or more, still more preferably For 300Pas or more, particularly preferably 400Pas or more.

In addition, for example, shear rate 1000s of (A) acetal resin at 190 DEG C^-1When viscosity be preferably 50Pas~ 2000Pa·s.If the viscosity is within the above range, can make in the polyoxymethylene resin composition of present embodiment (B) Modified material is uniformly dispersed.In addition, shear rate 1000s of (A) acetal resin at 190 DEG C^-1When viscosity be more preferably 1500Pas hereinafter, further preferably 1000Pas hereinafter, still more preferably be 500Pas hereinafter, particularly preferably 400Pas or less.On the other hand, shear rate 1000s of (A) acetal resin at 190 DEG C^-1When viscosity be more preferably 60Pas or more, further preferably 75Pas or more are still more preferably 90Pas or more, particularly preferably 150Pas or more.

It should be noted that above-mentioned viscosity can use Double Capillary Rheometer (Malvern (Malvern) corporation Make, Rosand, RH10) etc. be measured, can be suitable for measurement with defined temperature and shear rate.

< (B) modified material >

The polyoxymethylene resin composition of present embodiment contains (B) modified material.In addition, (B) modified material includes (b-1) Thermoplastic polyurethane and (b-2) graft rubber copolymer, (b-2) graft rubber copolymer have 2 layers or more of structure.

Relative to 100 mass parts of (A) acetal resin, the polyoxymethylene resin composition of present embodiment contains 0.5 mass (B) modified material of part~50 mass parts.Relative to 100 mass parts of (A) ingredient, by the way that the content of (B) ingredient is set as 0.5 More than mass parts, it is intended to can be improved impact resistance, in addition, by being set as 50 below the mass, it is intended to can protect It holds and improves impact resistance in the state of rigidity.

From the same viewpoint, (B) ingredient in the polyoxymethylene resin composition of present embodiment relative to (A) at The content of point 100 mass parts is preferably 1 mass parts or more, it is more than more preferably 3 mass parts, further preferably 5 mass parts with On, additionally, it is preferred that below the mass for 45, more preferably 40 below the mass, and further preferably 35 below the mass.

It should be noted that (A) acetal resin and (B) are modified in the polyoxymethylene resin composition of present embodiment Material can form island structure.Moreover, the structure can use electron microscope (transmission electron microscope (TEM), scanning electricity Sub- microscope (SEM)), the equipment such as optical microscopy observe.These equipment are general equipment, such as can enumerate Hitachi's system Make manufactured transmission electron microscope H-7650 etc..

It, then can be with if it is those skilled in the art in addition, the identification about (A) acetal resin and (B) modified material Easily judge.Specifically, can then be transmitted according to the electron beam as caused by molecular structure if it is transmission electron microscope The deep or light of color of the plane of delineation caused by the difference of property, the difference as caused by the coloring agents such as osmic acid or ruthenium tetroxide, by tying The difference of layer structure caused by crystalline substance polymer etc. and judged.

It in the present embodiment, can be from by the lock out operation such as filtering after reprecipitation, dissolution about (B) modified material Isolated and purified in polyoxymethylene resin composition, and ratio of components, structure, molecular weight can be calculated etc..In addition, for example by into Row¹H-NMR、¹³The various measurements such as C-NMR, two-dimentional NMR, MALDI-TOF MS, GPC, can determine repetitive structure, branched structure Deng molecular structure and the location information of various functional groups etc..

(b-1) thermoplastic polyurethane-

Thermoplastic polyurethane refers in the high-molecular compound that main chain has ammonia ester bond, and can to handle to thermoplasticity Elastomer.For high molecular structure, for example, can enumerate by rigidity carbamate segment (hard segment) with it is soft Property glycol segment (soft chain segment) constitute segmented copolymer.

Rigidity carbamate segment for example can by polyfunctional isocyanate's class with it is well known as chain extender The reaction of substance and obtain.For polyfunctional isocyanate's class, it is different that aromatic diisocyanate, ester ring type two can be used Cyanate or aliphatic diisocyanate etc..

For aromatic diisocyanate, for example, can enumerate 4,4 '-methyl diphenylene diisocyanates (MDI), Toluene di-isocyanate(TDI) (TDI) (such as 2,4 toluene diisocyanate and 2,6- toluene two as isomers can be enumerated Or mixtures thereof isocyanates), m-xylylene diisocyanate, terephthalylidene diisocyanate, 1,5- naphthalene two it is different Cyanate (NDI), 3,3 '-dimethyl -4,4 '-biphenyl diisocyanate (TODI),-two isocyanide of 2,2- diphenyl propane -4,4 ' Acid esters, paraphenylene diisocyanate, m-benzene diisocyanate etc..

For ester ring type diisocyanate, such as 4,4'-Dicyclohexylmethane diisocyanate can be enumerated (H₁₂MDI), isophorone diisocyanate (IPDI), pentamethylene -1,3- diisocyanate etc..

For aliphatic diisocyanate, such as 1,6- hexamethylene diisocyanate (HMDI), 1 can be enumerated, 4- tetramethylene diisocyanate etc..

For chain extender (otherwise referred to as crosslinking agent), such as molecular weight (molal weight) can be enumerated and be less than 500g/mol, the short-chain aliphatic of preferably smaller than 300g/mol, ester ring type or aromatic glycols, Diamines and triol Class.

For glycols, such as ethylene glycol, 1,3-PD, 1,2-PD, 1,4-butanediol, 1 can be enumerated, 3- butanediol, 1,5- pentanediol, 1,6-HD, 1,4- cyclohexanediol, 2,2- dimethyl -1,3- propylene glycol, 2,2- diethyl - 1,3- propylene glycol, 2- ethyl -2- butyl -1,3- propylene glycol, 2- methyl -2,4-PD, 2,2,4- trimethyl -1,3- penta 2 Alcohol, dihydroxy cyclopentane, 1,4 cyclohexane dimethanol, thiodiglycol, diethylene glycol, dipropylene glycol, 2- methyl-1,3- the third two Alcohol, 2- methyl -2- ethyl -1,3- propylene glycol, the dihydroxy ethyl ether of quinhydrones, hydrogenated bisphenol A etc..For Diamines, example Ethylenediamine, hexamethylene diamine, benzene dimethylamine, 4,4 '-diaminodiphenyl-methanes can such as be enumerated.As three alcohols Speech, can enumerate trimethylolpropane, glycerol etc..

For flexible glycol segment, such as can enumerate mumber average molar mass is 500g/mol~5000g/mol, excellent It is selected as polyetherdiol class, polyester-diol class, polyether ester glycols, the polycarbonate glycol class of 1000g/mol~3000g/mol Deng.

For polyetherdiol class, such as poly- (tetramethylene ether) glycol (PTMEG), poly- (propylene oxide) can be enumerated Glycol, polybutadiene diol, their copolymer are (for example, the copolymer of propylene oxide and ethylene oxide, tetrahydrofuran and epoxy The copolymer of ethane) etc..In addition, they for example can use the ring-opening polymerisation of ethylene oxide, propylene oxide or tetrahydrofuran and It obtains.

Polyester-diol class (such as can enumerate ethylene glycol, 1,3- third by above-mentioned polyetherdiol class or glycols Glycol, 1,2- propylene glycol, 1,4- butanediol, 1,3 butylene glycol, 2- methyl propanediol, 1,5- pentanediol, 3- methyl-1,5- penta 2 Alcohol, 1,6-HD, neopentyl glycol, nonanediol, 1,10- decanediol etc.) with dicarboxylic acids class (such as can enumerate glutaric acid, Adipic acid, pimelic acid, suberic acid, decanedioic acid, dodecanedioic acid, terephthalic acid (TPA), M-phthalic acid etc.) esterification or Person is obtained by corresponding ester exchange reaction.In addition, these polyester-diol classes (such as can also can be enumerated by lactone Caprolactone, propiolactone, valerolactone etc.) ring-opening polymerisation and obtain.

Polycarbonate glycol class can by make above-mentioned polyetherdiol class or glycols (such as can enumerate ethylene glycol, 1,3- propylene glycol, 1,2- propylene glycol, 1,4- butanediol, 1,3 butylene glycol, 2- methyl propanediol, 1,5- pentanediol, 3- methyl-1, 5- pentanediol, 1,6-HD, neopentyl glycol, nonanediol, 1,10- decanediol etc.) it is carried out with dipheryl carbonate esters or phosgene class It reacts and obtains.

For (b-1) thermoplastic polyurethane, such as ester type polyurethane can be enumerated (otherwise referred to as " polyester-type is poly- Urethane "), ether-based polyurethane (otherwise referred to as " polyether polyurethane "), ether-ether type polyurethane (otherwise referred to as " polyether ester type Polyurethane "), caprolactone type polyurethane (otherwise referred to as " polycaprolactone-type urethane ").In addition, from resistance to punching is more fully showed From the viewpoint of hitting property, (b-1) thermoplastic polyurethane is preferably ester type polyurethane, ether-ether type polyurethane, and more preferably ester type is poly- Urethane.In addition, from more fully show impact resistance from the viewpoint of, ester type polyurethane preferably comprise 2 kinds of polyol components ( It can be otherwise known as " polyol unit ").

(b-1) hardness of thermoplastic polyurethane is fallen into the range of the about Shore D 75 of Shore A 65~about.The hardness is by rigidity Carbamate segment and the ratio of glycol segment flexible determine.

(b-1) melt flow index of thermoplastic polyurethane measures at various temperatures, the carbamic acid dependent on rigidity The melting behavior of ester segment.This is also the measurement of the degree (molal weight of entire chain) of addition.

In addition, in the processing of composition, (b-1) thermoplastic polyurethane reaches by being set as following component ratio ranges To melt viscosity appropriate, the raising of impact resistance can be expected.

Ether about ether-based polyurethane, when isocyanate prepolymer composition (can also be otherwise known as " isocyanate units ") is set as 1 The ratio (molar ratio) of diol component (can also be otherwise known as " ether diol units ") be preferably 100 hereinafter, more preferably 50 hereinafter, Further preferably 20 hereinafter, additionally, it is preferred that be 8 or more, more preferably 10 or more, further preferably 13 or more.

On the other hand, about ester type polyurethane, ether-ether type polyurethane, carbonate polyurethane, isocyanate prepolymer composition is set The ratio of ester ingredient (can also be otherwise known as " ester units ") (carbonate component (or otherwise known as " carbonate unit ")) when being 1 Rate (molar ratio) is preferably 10 hereinafter, more preferably 8 hereinafter, further preferably 5 hereinafter, additionally, it is preferred that for 1 or more, more excellent 2 or more, further preferably 3 or more are selected as, is still more preferably 4 or more.By being above-mentioned by the ratio set of ester ingredient The upper limit is hereinafter, to tending to show good impact absorbency, in addition, by being set as above-mentioned lower limit or more, so as to Ensure better mobility.

It should be noted that above-mentioned ester ingredient refers to and reacting carboxylic acid composition with isocyanate prepolymer composition The ingredient of generation.

In addition, about ester type polyurethane, ether-ether type polyurethane, carbonate polyurethane, when isocyanate prepolymer composition is set as 1 Polyol component ratio (molar ratio) be preferably 10 hereinafter, more preferably 8 hereinafter, further preferably 6 hereinafter, in addition, Preferably 1 or more, more preferably 2 or more, further preferably 3 or more, it is still more preferably 5 or more.By by polyalcohol The ratio set of ingredient is the above-mentioned upper limit hereinafter, to tend to show good island structure, in addition, on by being set as Lower limit or more is stated, so as to ensure better viscosity.

Point of (b-1) thermoplastic polyurethane in polyoxymethylene resin composition and formed body comprising the resin combination Shot diameter is preferably 10nm~2000nm with equivalent circle diameter conversion.If the dispersion particle diameter of (b-1) thermoplastic polyurethane is 10nm or more, then available good dispersibility, can effectively show impact resistance.In addition, if (b-1) thermoplastic poly ammonia The dispersion particle diameter of ester is 2000nm hereinafter, then can more fully show impact resistance.From the same viewpoint, about poly- first The dispersion particle diameter of (b-1) thermoplastic polyurethane in urea formaldehyde composition and formed body comprising the resin combination is with equivalent Circular diameter conversion be more preferably 1500nm hereinafter, further preferably 1000nm hereinafter, still more preferably be 800nm hereinafter, In addition, more preferably 30nm or more, further preferably 40nm or more, are still more preferably 50nm or more.

It should be noted that in the present specification, equivalent circle diameter refers to: calculate the minor axis for the object substance being projected with And the value of the product of major diameter, the diameter of a circle with area identical with the value.In addition, the object substance ((b-1) in formed body Thermoplastic polyurethane, (b-2) graft rubber copolymer etc.) dispersion particle diameter can find out in the manner as described below.That is, utilizing The observations such as the transmission electron microscope face vertical with the resin flow direction of formed body, measurement are considered as the dispersion of object substance The minor axis and major diameter in the region in region.Then, the value for calculating the product of minor axis and major diameter, finds out with identical with the value The diameter of a circle of area.Furthermore, it is possible to which the object substance for arbitrary 10 or more finds out above-mentioned diameter of a circle, and to them It averages, regard obtained value as dispersion particle diameter.

(b-2) graft rubber copolymer-

Graft rubber copolymer is core shell rubbers, is gathered by what 1 layer or more of shell of stratum nucleare and covering stratum nucleare was constituted Close object.Here, the number of plies of shell is not particularly limited, or 2 layers or more.

In order to improve impact resistance, the ingredient for constituting the stratum nucleare of (b-2) graft rubber copolymer preferably has rubber bullet The ingredient of property, for example, can enumerate acrylic polymer, polysiloxane type polymers, polysiloxanes/acrylic polymer, Styrenic polymer, nitrile polymer, conjugated diolefine polymer, carbamate quasi polymer, olefin polymer etc.. In addition, constitute (b-2) graft rubber copolymer stratum nucleare at preferably acrylic polymer, polysiloxane type polymers, Polysiloxanes/acrylic polymer, conjugated diolefine polymer, carbamate quasi polymer.Wherein, from impact resistance with And from the perspective of heat-resistant aging, the ingredient for constituting the stratum nucleare of (b-2) graft rubber copolymer is preferably that polysiloxanes is birdsed of the same feather flock together Close object, acrylic polymer, polysiloxanes/acrylic polymer.

In addition, can preferably enumerate for as the ingredient for constituting stratum nucleare: make dimethyl siloxane and phenyl methyl silicon The silicone compounds such as oxygen alkane；The acyclic compounds such as ethyl acrylate, butyl acrylate and 2- ethylhexyl acrylate； Deng rubber constituent or the copolymer composition of these ingredients etc. obtained from polymerization.

For the ingredient of outermost shell as composition (b-2) graft rubber copolymer, it can enumerate containing unsaturation Carboxylic acid esters unit, the vinyl-based unit containing glycidyl, aliphatic ethylene base class unit, aromatic vinyl base class list Member, vinyl cyanide base class unit, maleimide unit, unsaturated dicarboxylic acid anhydride unit or other vinyl-based The polymer of unit etc..Wherein, from the viewpoint of impact resistance and heat-resistant aging, (methyl) acrylate is preferably comprised The polymer of class unit.

From when aging thermal stability, from the viewpoint of rigidity, in the ICP-MS analysis of (b-2) graft rubber copolymer The amount of Si element is preferably 1 mass of mass %~25 %.In addition, the amount of above-mentioned Si element is not particularly limited, more preferably 20 mass % hereinafter, further preferably 15 mass % hereinafter, still more preferably be 10 mass % hereinafter, in addition, more preferably It is still more preferably 2.5 mass % or more for 1.5 mass % or more, further preferably 2 mass % or more.

(b-2) manufacturing method of graft rubber copolymer is not particularly limited, can by well known polymerization, for example The side being polymerize comprising monomer with the mixture of polyfunctional vinyl monomer with specific ratios by suspension polymerisation, emulsion polymerization etc. Method and obtain.

(b-2) partial size of graft rubber copolymer is preferably 20nm~2000nm.(if b-2) graft rubber copolymer Partial size is 20nm or more, then dispersibility when melting mixing can be improved, in addition, if it is 2000nm hereinafter, can then make to set The processing when manufacture of oil/fat composition is easier.From the same viewpoint, the partial size of (b-2) graft rubber copolymer is more preferable Be still more preferably 50nm or more for 30nm or more, further preferably 40nm or more, in addition, more preferably 1500nm with Under, further preferably 1000nm is hereinafter, be still more preferably 800nm or less.

The dispersion particle diameter of (b-2) graft rubber copolymer in formed body with equivalent circle diameter conversion be preferably 20nm~ 2000nm.If the dispersion particle diameter of (b-2) graft rubber copolymer is 20nm or more, available good dispersibility can Effectively to show impact resistance.In addition, if the dispersion particle diameter of (b-2) graft rubber copolymer be 2000nm hereinafter, if can be with More fully show impact resistance.From the same viewpoint, the dispersion particle diameter of (b-2) graft rubber copolymer in formed body 1500nm is more preferably with equivalent circle diameter conversion hereinafter, further preferably 1000nm is hereinafter, still more preferably for 800nm Hereinafter, in addition, more preferably 30nm or more, further preferably 40nm or more, are still more preferably 50nm or more.

The stratum nucleare of above-mentioned (b-2) graft rubber copolymer and the mass ratio of shell are not particularly limited.

The mass ratio of stratum nucleare when (b-2) graft rubber copolymer is integrally set as 100 mass parts is preferably 10 mass parts More than, more than more preferably 20 mass parts, more than further preferably 30 mass parts.By the way that the mass ratio of stratum nucleare is set as Lower limit or more is stated, the entanglement of the mutual chain of (b-2) graft rubber copolymer can be made to tail off, can be further improved dispersibility.

In addition, the mass ratio of stratum nucleare when (b-2) graft rubber copolymer is integrally set as 100 mass parts is preferably 95 matter Part is measured hereinafter, more preferably 90 parts by weight are hereinafter, further preferably 85 below the mass.By the way that the mass ratio of stratum nucleare is set It is the above-mentioned upper limit hereinafter, can be further improved impact resistance.

(b-2) concentration of graft rubber copolymer preferably sulfuric acid radical ion is 0.1ppm~5ppm.If (b-2) is grafted rubber The concentration of sulfate ion in glue copolymer is 0.1ppm or more, then small sky can be intentionally formed in melting mixing Gap, therefore preferably, in addition, if it is 5ppm hereinafter, then can further improve thermal stability.From the same viewpoint, (b-2) concentration of the sulfate ion in graft rubber copolymer be more preferably 4ppm hereinafter, further preferably 3ppm hereinafter, It is still more preferably 2.5ppm or less.In addition, the concentration of the sulfate ion in (b-2) graft rubber copolymer is more preferably 0.2ppm or more, further preferably 0.3ppm or more are still more preferably 0.4ppm or more.

(b-2) concentration of the preferred calcium ion of graft rubber copolymer is 10ppm~500ppm.(if b-2) graft rubber The concentration of calcium ion in copolymer is 10ppm or more, then slight void can be intentionally formed in melting mixing, therefore excellent Choosing, in addition, if it is 500ppm hereinafter, then can be further improved thermal stability.From the same viewpoint, (b-2) is grafted The concentration of calcium ion in rubbery copolymer is more preferably 400ppm hereinafter, further preferably 350ppm is hereinafter, further Preferably 300ppm hereinafter, in addition, more preferably 15ppm or more, further preferably 20ppm or more, still more preferably for 30ppm or more.

For commercially available product as (b-2) graft rubber copolymer, such as " Metablen (registered trademark) " can be enumerated (manufacture of Mitsubishi's Li Yang company), " Kane Ace (registered trademark) " (manufacture of Kaneka company), " Staphyroid (registrar Mark) " (manufacture of Aica Kogyo company) or " Parapet (registered trademark) SA " (manufacture of Kuraray (Kuraray) company), (A Kema (ARKEMA) is public for " PARALOID (registered trademark) " (the Dow Chemical Company's manufacture), " Clearstrength (registered trademark) " Department's manufacture), " Durastrength (registered trademark) " (manufacture of A Kema (ARKEMA) company) etc., they can be used alone 1 Kind, it also can be used and combine two or more.

Among them, can more preferably use Metablen, more specifically S2001, S2006, S2030, S2100, The commercially available product of S2200, S2501, SX-006, SRK-200, SX-005, MR-01 as (b-2) graft rubber copolymer.

< (C) colorant >

The polyoxymethylene resin composition of present embodiment can contain (C) colorant as supplementary element (optional component). Here, (C) colorant refers to the substance for bringing variation to appearance under the action ofs the absorption of visible light, scattering, reflection etc..

(C) colorant that may exist in formed body about the polyoxymethylene resin composition in present embodiment, in addition to Other than original purpose coloring, can also have and being combined with (B) ingredient further improves the important of wear resistance Effect.Moreover, from the viewpoint of obtaining excellent wear resistance, it can be with the amount in aftermentioned range in present embodiment Contain (C) colorant in polyoxymethylene resin composition.

The reasons why improving wear resistance by the presence of (C) colorant, is still not clear, but may be considered due to: molding The surface hardness of body is improved because of (C) colorant.

(C) colorant is not limited to following substance, can enumerate inorganic pigment, organic dye pigment etc..

For inorganic pigment, the inorganic pigment for being typically used as the colouring application of resin can be enumerated, such as can To enumerate: the oxide of at least one kind of metal in the group being made of iron, zinc and titanium, selected from being made of iron, zinc and titanium Group at least one kind of metal carbonate, zinc sulphide, titanium oxide, zinc oxide, iron oxide, barium sulfate, titanium dioxide, sulfuric acid Barium, hydrated chromium oxide, chromium oxide, cobalt aluminate, blanc fixe, zinc potassium chromate, tetrabasic zinc chromate, potassium ferrocyanide, kaolin, Titan yellow, cobalt blue, ultramarine, cadmium, NiTi, lithopone, strontium, umber, ochre, azurite, malachite, azurmalachite, orpiment, realgar, occasion Sand, turquoise, manganese spar, sil, terre verte, raw sienna, raw umber, card plug your palm fibre, chalk, gypsum, burnt ochre, burnt umber, Lapis lazuli, azurite, malachite, coral powder, muscovite, cobalt blue, sky blue, cobalt violet, cobalt green, zinc white, titanium white, azarin, chrome oxide green, Mars black, chrome green, reddish brown Huang, alumina white, cadmium yellow, cadmium red, bright red, talcum, white carbon black, clay, manganese violet, rose cobalt violet, silvery white, Bronze, Cu-Zn alloy powder, aluminium powder, Prussian blue, cobalt yellow, talcum, wollastonite, mica titanium, carbon black, acetylene black, lampblack, furnace black, plant Property black, boneblack, calcium carbonate, barba hispanica etc..

It should be noted that above-mentioned " oxide of metal " also includes: comprising two or more in iron, zinc or titanium Metal " metal composite oxide ".

It for (C) colorant, can enumerate: at least 1 in the group being made of iron, zinc and titanium Carbonate, the zinc sulphide, oxidation of the oxide of kind of metal, at least one kind of metal in the group being made of iron, zinc and titanium Zinc, iron oxide, zinc potassium chromate, tetrabasic zinc chromate, zinc white, titanium white, alumina white, talcum, white carbon black, silvery white, carbon black, acetylene Black, lampblack, furnace black, calcium carbonate are as preferred colorant.

Among them, for (C) colorant, from the wear resistance of the polyoxymethylene resin composition of present embodiment Viewpoint considers that preferably Mohs' hardness is 8 colorants below.In addition, the more preferable Mohs' hardness of (C) colorant is 7 hereinafter, into one Step preferably 6 or less.

It should be noted that the Mohs' hardness of (C) colorant can use Moh's hardness scale and be measured.

For contaminating pigment as organic, it is not limited to following substance, such as condensation azo, quinones, phthalocyanine can be enumerated Class, monoazo class, diazonium class, polyazo class, Anthraquinones, heterocyclic, purple cyclic ketones class, quinacridine ketone, thioindigo class, class, twoThe organics such as piperazine class, phthalocyanines contaminate pigment.

For contaminating pigment particularly as organic, from the thermal stability of the polyoxymethylene resin composition of present embodiment From the viewpoint of, preferably it is condensed azo, quinones, phthalocyanines, Anthraquinones, heterocyclic, purple cyclic ketones class, quinacridine ketone, sulphur Indigoid, class, twoThe organic of piperazine class or phthalocyanines contaminates pigment.More preferably it is condensed azo, quinones, phthalocyanines, anthraquinone Class, heterocyclic, purple cyclic ketones class, quinacridine ketone, class or phthalocyanines organic contaminate pigment.Further preferably quinones, phthalein Cyanines class, Anthraquinones, heterocyclic, quinacridine ketone, class or phthalocyanines organic contaminate pigment.

Relative to 100 mass parts of (A) acetal resin, the polyoxymethylene resin composition of present embodiment preferably comprises 0.01 Mass parts~3 mass parts (C) colorant.Relative to 100 mass parts of (A) ingredient, by the way that the content of (C) ingredient is set as More than 0.01 mass parts, sufficient coloring can be brought to polyoxymethylene resin composition, in addition, by being set as 3 mass parts Hereinafter, the improvement of wearing character of the polyoxymethylene resin composition when small load is slided can be obtained fully.

From the same viewpoint, (C) colorant in the polyoxymethylene resin composition of present embodiment relative to (A) The content of 100 mass parts of acetal resin is more preferably 2.5 below the mass, and further preferably 2.0 below the mass, more into One step is preferably that 1.5 below the mass, particularly preferably 1.0 below the mass, and most preferably 0.8 below the mass, in addition, more It is more than preferably 0.05 mass parts, still more preferably for 0.1 mass parts more than.

The other additive > of <

The polyoxymethylene resin composition of present embodiment can be in the range of not damaging the purpose of the present invention containing existing The additives such as well known, the various stabilizers used in polyoxymethylene resin composition are as additional ingredient (optional component).

Stabilizer is not limited to following substance, such as agent for capturing that can enumerate antioxidant, formaldehyde or formic acid etc. etc..

They can be used singly or in combination of two or more.

For antioxidant, examined from the viewpoint of the thermal stability for the polyoxymethylene resin composition for improving present embodiment Consider, preferably hindered phenol anti-oxidants.Hindered phenol anti-oxidants are not particularly limited, and can be suitable for using well known hindered phenol Class antioxidant.

The agent for capturing of formaldehyde or formic acid etc. is not limited to following substance, such as can enumerate: melamine or polyamide-based tree Rouge etc. includes formaldehyde reactivity nitrogen compound and its polymer, the hydroxide of alkali or alkaline earth metal, inorganic acid salt, And carboxylate.For concrete example, calcium hydroxide, calcium carbonate, calcium phosphate, calcium silicates, line borate and rouge can be enumerated Fat acid calcium salt (calcium stearate, calcium myristate etc.).Fatty acid in above-mentioned fatty acid calcium salt can also be optionally substituted by a hydroxyl group.

Relative to 100 mass parts of (A) acetal resin, the content of antioxidant, such as hindered phenol anti-oxidants is preferred For 0.1 mass parts~2 mass parts.

In addition, relative to 100 mass parts of (A) acetal resin, agent for capturing, the polymer for example comprising formaldehyde reactive nitrogen Content be preferably 0.1 mass parts~3 mass parts.

In addition, relative to 100 mass parts of (A) acetal resin, the content of the fatty acid salt of agent for capturing, such as alkaline-earth metal Preferably 0.1 mass parts~1 mass parts.

(all property of polyoxymethylene resin composition)

The concentration of the polyoxymethylene resin composition preferably sulfuric acid radical ion of present embodiment is 0.01ppm~2.0ppm.Such as The concentration of sulfate ion in fruit polyoxymethylene resin composition is 0.01ppm or more, then can be in melting mixing intentionally Slight void is formed, therefore preferably, in addition, if it is 2.0ppm hereinafter, then can more improve thermal stability.From same viewpoint Consider, the concentration of the sulfate ion in polyoxymethylene resin composition is more preferably 1.0ppm hereinafter, further preferably 0.8ppm is hereinafter, still more preferably for 0.7ppm hereinafter, particularly preferably 0.6ppm is hereinafter, in addition, more preferably 0.02ppm More than, further preferably 0.03ppm or more is still more preferably 0.04ppm or more.

The concentration of the preferred calcium ion of the polyoxymethylene resin composition of present embodiment is 2ppm~100ppm.If polyformaldehyde The concentration of calcium ion in resin combination is 2ppm or more, then can intentionally form slight void in melting mixing, because This is preferred, in addition, if it is 100ppm hereinafter, then can be further improved thermal stability.From the same viewpoint, polyformaldehyde The concentration of calcium ion in resin combination is more preferably 90ppm hereinafter, further preferably 80ppm is hereinafter, further excellent 70ppm is selected as hereinafter, in addition, more preferably 3ppm or more, further preferably 4ppm or more, still more preferably for 5ppm with On.

(manufacturing method of polyoxymethylene resin composition)

The polyoxymethylene resin composition of present embodiment for example can by by (A) acetal resin of specified amount and (B) modified material and (C) colorant as needed, other additive melting mixings and obtain.

For the device of composition as the acetal resin formed body for obtaining present embodiment, public affairs can be enumerated The device known, such as: single screw rod or multi-screw extruder, roller, banbury mixers etc., wherein particularly preferably equipped with subtracting The double screw extruder of pressure device, side feeder equipment etc..

Material composition is mixed and the method for melting mixing is not particularly limited, can use those skilled in the art's public affairs The method known.Such as the method that can be listed below: (A) ingredient, (B) ingredient are all advanced with into super mixing machine, rotary drum The mixing such as formula mixing machine, V-type mixing machine, utilizes the method for double screw extruder together melting mixing；(A) ingredient is supplied to double The devices such as screw extruder, one side melting mixing, on one side from the method for intermediate addition (B) ingredient of device；By the one of (A) ingredient Part supply to the devices such as double screw extruder, one side melting mixing adds the remaining of (A) ingredient from the intermediate of device on one side The method etc. of a part and (B) ingredient.

The polyoxymethylene resin composition of present embodiment, can in the case where being manufactured using devices such as above-mentioned extruders To be obtained in the form of grain shape, can be used for forming etc..I.e., it is possible to be obtained by the polyoxymethylene resin composition of present embodiment To formed body.

(purposes of polyoxymethylene resin composition and formed body)

The polyoxymethylene resin composition of present embodiment and formed body comprising the polyoxymethylene resin composition can fit Ground is closed to be applied to require the purposes of impact resistance.Specifically, substance not limited to the following, such as can enumerate: with cam, cunning The gears such as block, lever, arm, clutch, felt clutch, idler gear, pulley, roller, roller (U ロ), key core, keycap, baffle, Spool, rotary shaft, connector, axis, bearing and guider etc. are the mechanism part of representative；It is molding resin component on inserts, embedding The molding resin component of part, chassis, pallet, side plate, using printer and duplicator as the business automation equipment component of representative； The image documentation equipments component such as DV and digital camera；CD, DVD, Blu-ray Disc (Blu-ray Disc), other CDs Driver；Using navigation system and mobile personal computer as the music of representative, image or information equipment, with mobile phone and biography Prototype is the communication equipment component of representative；Electrical equipment component；Electronic equipment component etc..

In addition, the polyoxymethylene resin composition of present embodiment and the formed body comprising the resin combination are as automobile Component for example can be applied to: be the fuel associated components of representative with fuel tank, fuel pump module, valve type, oil tank flange etc.；With Car door lock, door handle, window regulator, loudspeaker grid etc. are the car door associated components of representative；With safety belt slip ring, press Button etc. is the safety belt associated components of representative；The components such as stacked switch component, Switch, clip class.

In addition, the polyoxymethylene resin composition of present embodiment and the formed body comprising the resin combination are as other Articles or component can also be for example suitably used as: the pen tip of writing implement, the mechanism part for passing in and out pen core；Washstand, row The mouth of a river and drain cock switching mechanism component；Sling, adjuster, the button of clothes；The nozzle of watering, water spray hose connection Part；The building product of balustrade portion and the supporter as flooring material；Toy, fastener, chain, conveyer belt, band Button, sporting goods, automatic vending machine (switch portion blocking mechanism, commodity output mechanism component), furniture, musical instrument, residential equipment machine Device component.

Moreover, the polyoxymethylene resin composition of present embodiment and the formed body comprising the resin combination can also answer For it is preferable to use the various uses of polyformaldehyde, industrial applicabilities with higher all the time.

Embodiment

Hereinafter, explaining the present invention in detail by embodiment, but the present invention is not limited only to these embodiments.

The preparation of < material composition prepares >

(A) acetal resin is prepared in a manner of as shown in following respectively, and uses substance as shown below as (b- 1) thermoplastic polyurethane and (b-2) graft rubber copolymer.

(1) acetal resin (A-1)

By the twin shaft self-cleaning type polymerization machine (L/D=8 (L: from the original of polymerization machine of the collet with the thermal medium that can circulate Expect distance (m) of the supply mouth to outlet, D: the internal diameter (m) of polymerization machine) it is adjusted to 80 DEG C.By threeAlkane was with 4kg/ hours, work For comonomer 1,3- dioxolane using 200g/ hours, as chain-transferring agent dimethoxym ethane relative to threeAlkane 1 rubs You are 1.8 × 10^-3Mole amount be continuously added in the polymerization machine.

Further, by as the boron trifluoride di-n-butyl ether complexes of polymerization catalyst relative to threeAlkane 1 rubs You are 1.5 × 10^-5Mole amount be continuously added in polymerization machine and polymerize.The polyformaldehyde being discharged from polymerization machine is total to Polymers is put into 0.1% aqueous solution of triethylamine, has carried out the inactivation of polymerization catalyst.

The polyacetal copolymer after inactivation is filtered with centrifugal separator, then relative to polyacetal copolymer 100 mass parts are added 1 mass parts of aqueous solution containing quaternary ammonium compound, are equably mixed, and supply to double with exhaust outlet Axis screw-type extruder adds the water of 0.5 mass parts relative to 100 mass parts of polyacetal copolymer of the melting in extruder, Polyacetal copolymer has been carried out not under conditions of residence time 7 minutes in 200 DEG C of the set temperature of extruder, extruder Stablize the decomposition removal of terminal part.At this point, it is 20 mass ppm that the additive amount of quaternary ammonium compound, which is scaled nitrogen quantity,.

In polyacetal copolymer after being decomposed to unstable terminal part, add double as the triethylene glycol of antioxidant [3- (3- tert-butyl -5- methyl -4- hydroxy phenyl) propionic ester] 0.3 mass parts, in the extruder with exhaust outlet, in vacuum It spends under conditions of 20 supports and carries out devolatilization, while being squeezed out in the form of strands from extruder die head, and be granulated.

Using the polyacetal copolymer obtained in this way as acetal resin (A-1).Acetal resin (A-1) Melt flow rate (MFR) is 9g/10 minutes (ISO-1133 condition D).

In addition, the melt viscosity about acetal resin (A-1), 190 DEG C of shear rate 100s^-1When viscosity be 550Pas, 190 DEG C of shear rate 1000s^-1When viscosity be 250Pas.

(2) acetal resin (A-2)

By the twin shaft self-cleaning type polymerization machine (L/D=8 (L: from the original of polymerization machine of the collet with the thermal medium that can circulate Expect distance (m) of the supply mouth to outlet, D: the internal diameter (m) of polymerization machine) it is adjusted to 80 DEG C.By threeAlkane was with 4kg/ hours, work For comonomer 1,3- dioxolane using 200g/ hours, as chain-transferring agent dimethoxym ethane relative to threeAlkane 1 rubs You are 1.10 × 10^-3Mole amount be continuously added in the polymerization machine.

Using the polyacetal copolymer obtained in this way as acetal resin (A-2).Acetal resin (A-2) Melt flow rate (MFR) is 3g/10 minutes (ISO-1133 condition D).

In addition, the melt viscosity about acetal resin (A-2), 190 DEG C of shear rate 100s^-1When viscosity be 900Pas, 190 DEG C of shear rate 1000s^-1When viscosity be 350Pas.

(3) acetal resin (A-3)

By the twin shaft self-cleaning type polymerization machine (L/D=8 (L: from the original of polymerization machine of the collet with the thermal medium that can circulate Expect distance (m) of the supply mouth to outlet, D: the internal diameter (m) of polymerization machine) it is adjusted to 80 DEG C.By threeAlkane was with 4kg/ hours, work For comonomer 1,3- dioxolane using 200g/ hours, as chain-transferring agent dimethoxym ethane relative to threeAlkane 1 rubs You are 3.0 × 10^-3Mole amount be continuously added in the polymerization machine.

Using the polyacetal copolymer obtained in this way as acetal resin (A-3).Acetal resin (A-3) Melt flow rate (MFR) is 45g/10 minutes (ISO-1133 condition D).

In addition, the melt viscosity about acetal resin (A-3), 190 DEG C of shear rate 100s^-1When viscosity be 350Pas, 190 DEG C of shear rate 1000s^-1When viscosity be 100Pas.

(4) thermoplastic polyurethane (b-1-1)

The commercially available ester type polyurethane (ESTANE: registered trademark) being made of duplicate hard segment and soft chain segment is used. The molar ratio respectively formed are as follows: methyl diphenylene diisocyanate (isocyanate prepolymer composition): adipic acid (ester ingredient): tetramethylene two Alcohol (polyol component): ethylene glycol (polyol component)=1:4.5:3.3:2.2.

(5) thermoplastic polyurethane (b-1-2)

Commercially available ether-based polyurethane (the RESAMINE: registrar being made of duplicate hard segment and soft chain segment is used Mark).The molar ratio respectively formed are as follows: methyl diphenylene diisocyanate: tetramethylene glycol=1:8.8.

(6) thermoplastic polyurethane (b-1-3)

The commercially available caprolactone type polyurethane (Miractran: registration being made of duplicate hard segment and soft chain segment is used Trade mark).The molar ratio respectively formed are as follows: methyl diphenylene diisocyanate: tetramethylene glycol: polycaprolactone polyol=1:1: 3。

They can be prepared by the method recorded in WO2011125540 bulletin etc..

(7) graft rubber copolymer (b-2-1)

Commercially available Metablen S2100 is used.The amount of the Si element of the graft rubber copolymer is 2.9 mass %.

(8) graft rubber copolymer (b-2-2)

Commercially available Metablen S2006 is used.The amount of the Si element of the graft rubber copolymer is 3.5 mass %.

(9) graft rubber copolymer (b-2-3)

Commercially available Metablen S2030 is used.The amount of the Si element of the graft rubber copolymer is 11.1 mass %.

(10) graft rubber copolymer (b-2-4)

Commercially available KANE ACE MR-01 is used.The amount of element of the Si of the graft rubber copolymer is 27 mass %.

(11) graft rubber copolymer (b-2-5)

Commercially available Metablen C223A is used.

(12) graft rubber copolymer (b-2-6)

Commercially available Metablen E875A is used.

(13) graft rubber copolymer (b-2-7)

Commercially available KANE ACE FM-53 is used.

The preparation of < polyoxymethylene resin composition and the production > of formed body

According to following step, the preparation of polyoxymethylene resin composition and the production of formed body have been carried out.

(1) preparation of polyoxymethylene resin composition

It is formulated according to shown in table 1 and table 2, using extruder, (TEM-26SS of Toshiba Machinery Co., Ltd.'s manufacture is squeezed out Machine (L/D=48, have exhaust outlet), be all set to 200 DEG C for barrel temperature, by 90 mass parts that are equivalent to of (A) ingredient Particle and (b-2) ingredient are individually supplied from quantitative feeder by the main feed oral area at the top of extruder respectively.In addition, by (A) The particle for being equivalent to 10 mass parts and (b-1) ingredient of ingredient are individually supplied from quantitative feeder by extruder side respectively. According to circumstances, the supplementary elements such as (C) ingredient, other additives and the particle for being equivalent to 90 mass parts of (A) ingredient are mixed together It closes, is individually supplied by the main feed oral area at the top of extruder.In extrusion output 15kg/ hours, screw speed 150rpm Under conditions of resin mixture is squeezed out with threadiness, bathed and be quickly cooled down by strands, cut off, obtained using strand cutting machine The polyoxymethylene resin composition of particle shape shape.

(2) production of formed body

By the polyoxymethylene resin composition of obtained grain shape, injection (mo(u)lding) machine (Toshiba Machinery Co., Ltd. is used Manufacture, EC-75NII), barrel temperature is set as 205 DEG C, is 60 DEG C by mold temperature set, in 35 seconds injection time, cooling It is formed under time 15 seconds injecting conditions, results in the multipurpose test film (formed body) according to ISO294-1.

< evaluating characteristics >

Using the polyoxymethylene resin composition or multipurpose test film of obtained grain shape, according to following step pair Various characteristics are evaluated.

(1) notched simple beam impact strength (23 DEG C)

Using obtained multipurpose test film, it is determined according to ISO179-1.Show the result in table 1 and table 2.Value It is bigger, then it is judged as that impact resistance is more excellent.

(2) stretch modulus

Using obtained multipurpose test film, it is determined according to ISO527.Show the result in table 1 and table 2.Value is got over Greatly, then it is judged as that rigidity is more excellent.

(3) coefficient of friction

Using ball dish-type reciprocal movement friction abrasion tester (AFT-15MS type, Precision Co., Ltd, Japan manufacture), 23 DEG C, in the environment of humidity 50%, in load 19.6N, linear velocity 30mm/s, reciprocal distance 20mm, reciprocal time 10,000 times items Under part, the sliding test on the surface of obtained multipurpose test film is implemented.SUS304 ball (ball of diameter 5mm) has been used to make For ball material.Determine coefficient of friction when reciprocal time reaches 10,000 times.Show the result in table 1 and table 2.It is worth smaller, then judges It is more excellent for sliding property.

(4) heat retention limit time

By the polyoxymethylene resin composition of obtained grain shape, injection (mo(u)lding) machine (Toshiba Machinery Co., Ltd. is used Manufacture, EC-75NII), barrel temperature is set as 210 DEG C, is 30 DEG C by mold temperature set, in 35 seconds injection time, cooling It is formed under time 15 seconds injecting conditions, results in the multipurpose test film (formed body) according to ISO294-1.Into It has gone 10 times and has been injection moulded, then in the state of being plasticized resin in barrel, stopped in the state that heater is heating and continuous Only forming operation stops the stipulated time, then starts to form again, it is thus identified that the generation shape of the crazing on initial formed body Condition.The confirmation of the generation situation of crazing is 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes in the dwell time of molding machine In the case where implement.Moreover, crazing is appeared in the time of the whole surface of formed body as when the heat retention limit in barrel Between.Show the result in table 1 and table 2.Limit time is longer, then stability when being evaluated as heat retention is more excellent.

(5) stretching strength retentivity after aging

Using obtained multipurpose test film, long-term thermal stability evaluation is implemented.Specifically, multipurpose is tested Piece is put into the Geer -Evans-oven under 145 DEG C of environment, is exposed to high-heat environment lower 35 days.It is taken out after 35 days, after 24 hours The measurement of tensile strength has been carried out by the method according to ISO527-1.Tensile strength before exposure and the stretching after exposure is strong Degree is compared, and calculates strength retention.Show the result in table 1 and table 2.The value is then judged as more excellent closer to 100 It is different.

As table 1 and table 2 it is found that the impact resistance of polyoxymethylene resin composition involved in embodiment, rigidity, sliding property, And stability when heat retention is good, wherein the polyoxymethylene resin composition contains (A) acetal resin and packet (B) modified material containing (b-1) thermoplastic polyurethane and (b-2) graft rubber copolymer, and relative to (A) polyformaldehyde tree 100 mass parts of rouge, the content of (B) modified material are 0.5 mass parts~50 mass parts.

Industrial applicability

Claims

1. a kind of polyoxymethylene resin composition, which is characterized in that

The polyoxymethylene resin composition contains 0.5 mass parts~50 of 100 mass parts of (A) acetal resin and (B) modified material Mass parts,

(b-2) graft rubber copolymer has 2 layers or more of structure.

2. polyoxymethylene resin composition as described in claim 1, wherein the ICP-MS of (b-2) graft rubber copolymer The amount of Si element in analysis is 1 mass of mass %~25 %.

3. polyoxymethylene resin composition as claimed in claim 1 or 2, wherein (b-1) thermoplastic polyurethane is poly- for ester type Urethane.

4. polyoxymethylene resin composition as claimed in claim 3, wherein in the ester type polyurethane, by isocyanate prepolymer composition The ratio (molar ratio) of ester ingredient when being set as 1 is 4~5 and the ratio (molar ratio) of polyol component is 5~6.

5. polyoxymethylene resin composition as described in claim 3 or 4, wherein the ester type polyurethane include 2 kinds of polyalcohols at Point.

6. the polyoxymethylene resin composition as described in any one of claims 1 to 5, wherein (b-2) the graft rubber copolymerization Object includes polysiloxanes/acrylic polymer, and the Si element in the ICP-MS analysis of (b-2) graft rubber copolymer Amount be 2 mass of mass %~10 %.

7. such as polyoxymethylene resin composition described in any one of claims 1 to 6, wherein the polyoxymethylene resin composition In sulfate ion concentration be 0.01ppm~0.2ppm.

8. the polyoxymethylene resin composition as described in any one of claims 1 to 7, wherein (A) acetal resin melts Body flow rate is 0.1g/10 minutes~60g/10 minutes.

9. such as polyoxymethylene resin composition described in any item of the claim 1 to 8, wherein the polyoxymethylene resin composition For grain shape.

10. a kind of formed body, which is characterized in that the formed body includes polyformaldehyde tree described in any one of claims 1 to 9 Oil/fat composition.