JP2017137386A - Polyacetal resin composition and resin molded article obtained by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyacetal resin composition which has excellent impact resistance and is capable of sufficiently suppressing contamination of a mold and generation of formaldehyde, and a resin molded article obtained by using the same.SOLUTION: In the polyacetal resin composition, 1-120 pts.mass of a thermoplastic polyurethane (B) and 0.01-5 pts.mass of a formaldehyde scavenger (C) are blended based on 100 pts.mass of a polyacetal resin (A). The formaldehyde scavenger (C) comprises at least one selected from the group consisting of specific dihydrazone compounds (C1) and hydrazide compounds (C2). The thermoplastic polyurethane (B) has a residual isocyanate content of 0.10 mass% or less and a water content of 3,000 mass ppm or less and exhibits a melt viscosity of 200,000 poise or more at 180°C.SELECTED DRAWING: None

Description

  The present invention relates to a polyacetal resin composition and a resin molded product obtained using the same.

  The engineering plastics polyacetal resin has excellent mechanical properties, sliding properties, friction / abrasion properties, heat resistance, molding processability, and the like, and is often used as a basic component for automobiles, OA equipment and the like. On the other hand, thermoplastic polyurethane has good compatibility with the polyacetal resin, and can impart impact resistance to the polyacetal resin. For this reason, compositions containing a polyacetal resin and a thermoplastic polyurethane are often used.

  As such a composition, what is disclosed by the following patent document 1 is known. In the following Patent Document 1, 1 to 120 parts by weight of a thermoplastic polyurethane resin and 0.01 to 5 parts by weight of a formaldehyde scavenger are blended with 100 parts by weight of a polyacetal resin. A polyacetal resin composition having a residual isocyanate amount of 1% by mass or less, a water content of 3000 ppm by mass or less, and a melt viscosity of 180,000 poise or more at 180 ° C. is disclosed.

Japanese Patent No. 5632809

  However, the composition described in Patent Document 1 has room for improvement in terms of suppression of the amount of formaldehyde generated and sufficient metal contamination resistance and impact resistance.

  An object of this invention is to provide the polyacetal resin composition which has the outstanding impact resistance, and can fully suppress generation | occurrence | production of mold contamination and formaldehyde, and a resin molded product obtained by using the same.

  This inventor repeated earnest research in order to solve the said subject. As a result, the present inventors use dihydrazone compounds or hydrazone compounds having specific end groups that are less likely to cause steric hindrance, thereby particularly increasing the reactivity between the dihydrazone compound or hydrazone compound and formaldehyde, and sufficiently generating formaldehyde. I thought it could be suppressed. In addition, the product obtained at this time is difficult to bleed out from the polyacetal resin composition, or even if bleeded out, it is difficult to adhere to the mold, and the contamination of the mold during molding can be sufficiently suppressed. I thought. Furthermore, the present inventor has found that it is effective for improving the impact resistance to make the melt viscosity of the thermoplastic polyurethane a predetermined value or more. As a result of further earnest studies, the present inventor has found that the above-described problems can be solved by the following invention.

（上記式中、Ｒ^１は炭素数４〜２０の脂肪族炭化水素基、炭素数６〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を示す。Ｒ^２〜Ｒ^５はそれぞれ独立に、水素原子、又は炭素数１若しくは２のアルキル基を示し、Ｒ^２及びＲ^３のうち少なくとも一方は炭素数１又は２のアルキル基を示し、Ｒ^４及びＲ^５のうち少なくとも一方は炭素数１又は２のアルキル基を示す。）

（上記式中、Ｒ^８は炭素数４〜２０の脂肪族炭化水素基、炭素数６〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を示す。Ｒ^６及びＲ^７はそれぞれ独立に、炭素数３〜１２の脂環式炭化水素基を示す。） That is, in the present invention, the thermoplastic polyurethane (B) is blended at a ratio of 1 to 120 parts by mass and the formaldehyde scavenger (C) is at a ratio of 0.01 to 5 parts by mass with respect to 100 parts by mass of the polyacetal resin (A). And the formaldehyde scavenger (C) comprises at least one selected from the group consisting of a dihydrazone compound (C1) and a hydrazide compound (C2), and the dihydrazone compound (C1) is represented by the following formula (1): The thermoplastic polyurethane (B) is composed of at least one selected from the group consisting of a dihydrazone compound (C1-1) represented by formula (2) and a dihydrazone compound (C1-2) represented by the following formula (2). It has a residual isocyanate content of 10% by weight or less, a moisture content of 3000 ppm by weight or less, and a 180,000 poise or more at 180 ° C. A polyacetal resin composition showing a melt viscosity.

(In the above formula, R ¹ represents an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. R ² to R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, at least one of R ² and R ³ represents an alkyl group having 1 or 2 carbon atoms, and among R ⁴ and R ⁵ At least one represents an alkyl group having 1 or 2 carbon atoms.)

(In the above formula, R ⁸ represents an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. R ⁶ and R < ⁷ > shows a C3-C12 alicyclic hydrocarbon group each independently.)

  According to this polyacetal resin composition, it has excellent impact resistance and can sufficiently suppress mold contamination and formaldehyde generation.

  Here, the present inventors speculate as follows why the impact resistance can be improved and the generation of formaldehyde can be sufficiently suppressed by setting the melt viscosity of the thermoplastic polyurethane (B) within the above range. Yes.

  That is, when the melt viscosity of the thermoplastic polyurethane (B) is 200,000 poise or more, the impact resistance of the polyacetal resin composition is improved. For this reason, it is not necessary to use an excessive amount of the thermoplastic polyurethane (B) in order to obtain impact resistance using the thermoplastic polyurethane (B). As a result, it is difficult not only to impair the inherent rigidity of the polyacetal resin, but also to inhibit the formaldehyde generation suppression effect, which is another object of the present invention. For these reasons, the present inventor presumes that by setting the melt viscosity of the thermoplastic polyurethane (B) within the above range, impact resistance can be improved and generation of formaldehyde can be sufficiently suppressed.

In the polyacetal resin composition, in the general formula (1), it is preferred that R ¹ is an aliphatic hydrocarbon group having 6 to 12 carbon atoms.

  In this case, the reactivity between the dihydrazone compound (C1) and formaldehyde becomes higher, and generation of formaldehyde is more effectively suppressed. Further, contamination of the mold during molding can be more sufficiently suppressed.

In the polyacetal resin composition, in the general formula (1), when R ² and R ⁴ are ethyl groups, R ³ and R ⁵ are hydrogen atoms, and R ² and R ⁴ are methyl groups. In some cases, R ³ and R ⁵ are preferably a hydrogen atom or a methyl group.

  In this case, the reactivity between the dihydrazone compound (C1) and formaldehyde becomes higher, and generation of formaldehyde is more effectively suppressed. Further, contamination of the mold during molding can be more sufficiently suppressed.

  In the said polyacetal resin composition, it is preferable that the said dihydrazone compound (C1) is mix | blended in the ratio of 0.05-3 mass parts with respect to 100 mass parts of said polyacetal resins (A).

  In this case, compared with the case where the compounding quantity of a dihydrazone compound (C1) is less than 0.05 mass part, generation | occurrence | production of formaldehyde can be suppressed more fully. Moreover, compared with the case where the compounding quantity of a dihydrazone compound (C1) exceeds 3 mass parts, the more excellent impact resistance can be provided with respect to the resin molded product obtained by shape | molding a polyacetal resin composition.

  In the said polyacetal resin composition, it is preferable that the hydrazide compound (C2) is mix | blended in the ratio of 0.01-1 mass part with respect to 100 mass parts of said polyacetal resin (A).

  In this case, compared with the case where the compounding quantity of the hydrazide compound (C2) with respect to 100 mass parts of polyacetal resin (A) is less than 0.01 mass part, generation | occurrence | production of formaldehyde can be suppressed more fully. Moreover, compared with the case where the compounding quantity of the hydrazide compound (C2) with respect to 100 mass parts of polyacetal resin (A) exceeds 1 mass part, the contamination of the metal mold | die at the time of a molding process can fully be suppressed, and a polyacetal resin composition is shape | molded. More excellent impact resistance can be imparted to the resin molded product obtained in this manner.

In the said polyacetal resin composition, it is preferable that R represented by following formula (3) is larger than 50 mass%.
R = A _C1 / (A _C1 + A _C2 ) × 100 (3)
(In Formula (3), A _C1 represents the amount of the dihydrazone compound (C1) to 100 parts by mass of the polyacetal resin (A), and A _C2 represents the hydrazide compound (C2 to 100 parts by mass of the polyacetal resin (A)). ))

  In this case, generation of formaldehyde can be effectively suppressed.

  In the said polyacetal resin composition, it is preferable that said R is 60-90 mass%.

  In this case, generation of formaldehyde can be more effectively suppressed.

  In the said polyacetal resin composition, it is preferable that a hydrazide compound (C2) is comprised by at least 1 sort (s) from the group which consists of a monohydrazide compound and a dihydrazide compound.

  In this case, compared with the case where the hydrazide compound (C2) is composed of a hydrazide compound having three or more hydrazide groups in the molecule, the hydrazide group can be efficiently dispersed in the polyacetal resin, and the hydrazide compound (C2) The amount added can be more sufficiently suppressed.

  In the polyacetal resin composition, the hydrazide compound (C2) is particularly preferably composed of a dihydrazide compound.

  In this case, generation of formaldehyde can be more sufficiently suppressed as compared with the case where the hydrazide compound is composed of only the monohydrazide compound or the case of being composed of the monohydrazide compound and the dihydrazide compound.

  Moreover, this invention is a resin molded product formed by shape | molding the polyacetal resin composition mentioned above.

  This resin molded product has excellent impact resistance and can sufficiently suppress the generation of formaldehyde.

  ADVANTAGE OF THE INVENTION According to this invention, the polyacetal resin composition which has the outstanding impact resistance, and can fully suppress generation | occurrence | production of mold contamination and formaldehyde, and a resin molded product obtained by using the same are provided.

  Hereinafter, the present invention will be described in detail.

（上記式中、Ｒ^１は炭素数４〜２０の脂肪族炭化水素基、炭素数６〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を示す。Ｒ^２〜Ｒ^５はそれぞれ独立に、水素原子、又は炭素数１若しくは２のアルキル基を示し、Ｒ^２及びＲ^３のうち少なくとも一方は炭素数１又は２のアルキル基を示し、Ｒ^４及びＲ^５のうち少なくとも一方は炭素数１又は２のアルキル基を示す。）

（上記式中、Ｒ^８は炭素数４〜２０の脂肪族炭化水素基、炭素数６〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を示す。Ｒ^６及びＲ^７はそれぞれ独立に、炭素数３〜１２の脂環式炭化水素基を示す。） In the present invention, the thermoplastic polyurethane (B) is blended at a ratio of 1 to 120 parts by mass and the formaldehyde scavenger (C) is at a ratio of 0.01 to 5 parts by mass with respect to 100 parts by mass of the polyacetal resin (A). The blended formaldehyde scavenger (C) is composed of at least one selected from the group consisting of a dihydrazone compound (C1) and a hydrazide compound (C2), and the dihydrazone compound (C1) is represented by the following formula (1). It is composed of at least one selected from the group consisting of a dihydrazone compound (C1-1) and a dihydrazone compound (C1-2) represented by the following formula (2), and the thermoplastic polyurethane (B) is 0.10% by mass or less. Having a residual isocyanate content of 3000 ppm by weight and a melt viscosity of at least 200,000 poise at 180 ° C. An acetal resin composition.

(In the above formula, R ¹ represents an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. R ² to R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, at least one of R ² and R ³ represents an alkyl group having 1 or 2 carbon atoms, and among R ⁴ and R ⁵ At least one represents an alkyl group having 1 or 2 carbon atoms.)

(In the above formula, R ⁸ represents an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. R ⁶ and R < ⁷ > shows a C3-C12 alicyclic hydrocarbon group each independently.)

(A) Polyacetal resin A polyacetal resin has a divalent oxymethylene group as a structural unit. The polyacetal resin used in the present invention includes, in addition to the acetal homopolymer consisting of only this structural unit, a copolymer (block copolymer) or terpolymer containing one or more repeating structural units other than oxymethylene groups, and a linear structure. Not only that, it may have a branched or crosslinked structure.

  In order to produce the polyacetal resin, a main raw material containing trioxane is usually used. The main raw material is composed only of trioxane when producing the acetal homopolymer. When the copolymer or terpolymer is produced, the main raw material includes a comonomer in addition to trioxane.

  Although the comonomer used for manufacture of a copolymer or a terpolymer is not specifically limited, Cyclic formal, ether, etc. are mentioned. Specific examples include 1,3-dioxolane, 2-ethyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 2-butyl-1,3-dioxolane, 2,2-dimethyl-1, 3-dioxolane, 2-phenyl-2-methyl-1,3-dioxolane, 4-methyl-1,3-dioxolane, 2,4-dimethyl-1,3-dioxolane, 2-ethyl-4-methyl-1, 3-dioxolane, 4,4-dimethyl-1,3-dioxolane, 4,5-dimethyl-1,3-dioxolane, 2,2,4-trimethyl-1,3-dioxolane, 4-hydroxymethyl-1,3 -Dioxolane, 4-butyloxymethyl-1,3-dioxolane, 4-phenoxymethyl-1,3-dioxolane, 4-chloromethyl-1,3-dioxolane, 1,3-dioxolane Kikabishikuro [3,4.0] nonane, ethylene oxide, propylene oxide, Petit alkylene oxide, epichlorohydrin, styrene oxide, Okishitan, 3,3-bis (chloromethyl) oxetane, tetrahydrofuran, and oxepane, and the like. Of these, 1,3-dioxolane is particularly preferred.

  Although the addition amount of a comonomer is not specifically limited, It is preferable that it is 0.2-30 mass parts with respect to 100 mass parts of trioxane, More preferably, it is 0.5-20 mass parts. When the addition amount of the comonomer is more than 30 parts by mass, the polymerization yield decreases, and when it is less than 0.2 part by mass, the thermal stability decreases.

(B) Thermoplastic polyurethane As the thermoplastic polyurethane (B), polyurethane having thermoplasticity is used. Polyurethane can be obtained by reacting a diol with a diisocyanate.

  Examples of the diol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, and the like.

  Examples of the diisocyanate include aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate. These can be used alone or in combination of two or more.

  Examples of the aromatic diisocyanate include 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2-methylene diphenylene diisocyanate, and naphthalene diisocyanate.

  Examples of the aliphatic diisocyanate include hexamethylene diisocyanate.

  Examples of the alicyclic diisocyanate include isophorone diisocyanate, 4,4′-methylene-bis- (cyclohexyl isocyanate), 1,3-bis- (isocyanate methyl) cyclohexane, 1,4-bis- (isocyanate methyl) cyclohexane, and the like. Can be mentioned.

  Diisocyanates are dimers and trimers of the above aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates (hereinafter sometimes referred to as “isocyanate compounds”), carbodiimide modified products of these isocyanate compounds, It may be a prepolymer with a monohydric alcohol, or a blocked isocyanate compound obtained by blocking these isocyanate compounds with a blocking agent such as phenol, primary alcohol, or caprolactam.

  The compounding quantity of thermoplastic polyurethane (B) with respect to 100 mass parts of polyacetal resin (A) is 1-120 mass parts. When the blending amount of the thermoplastic polyurethane (B) is less than 1 part by mass, the impact resistance becomes insufficient. On the other hand, if the amount of the thermoplastic polyurethane (B) exceeds 120 parts by mass, the generation of formaldehyde cannot be sufficiently suppressed. Further, the inherent rigidity of the polyacetal resin (A) is significantly impaired.

  The blending amount of the thermoplastic polyurethane (B) with respect to 100 parts by mass of the polyacetal resin (A) gives sufficient impact resistance to the polyacetal resin composition as long as the original rigidity of the polyacetal resin (A) is not impaired. For the reason, it is preferably 10 parts by mass to 120 parts by mass, more preferably 33 parts by mass to 110 parts by mass.

  In the thermoplastic polyurethane (B), diisocyanate that did not contribute to the reaction may remain. This residual diisocyanate reacts with the dihydrazone compound or hydrazide compound to reduce the effect of suppressing formaldehyde generation, so that it is preferably as small as possible. Specifically, the amount of the remaining diisocyanate is 0.10% by mass or less based on the thermoplastic polyurethane (B) (100% by mass). When the amount of residual isocyanate exceeds 0.10% by mass, generation of formaldehyde cannot be sufficiently suppressed. The amount of residual isocyanate is preferably 0.05% by mass or less.

  In order to reduce the residual isocyanate amount to 0.10% by mass or less, for example, a method of adjusting the drying conditions after the production of the thermoplastic polyurethane (B) and causing the reaction of unreacted isocyanate groups remaining in the resin to proceed. Is mentioned.

  The water content in the thermoplastic polyurethane (B) is 3000 ppm by mass or less. If the water content in the thermoplastic polyurethane (B) exceeds 3000 ppm by mass, the generation of formaldehyde cannot be sufficiently suppressed.

  The water content in the thermoplastic polyurethane (B) is preferably 1500 mass ppm or less. In this case, compared with the case where the water content in thermoplastic polyurethane (B) exceeds 1500 mass ppm, generation | occurrence | production of formaldehyde can be suppressed more fully.

  The moisture content in the thermoplastic polyurethane (B) can be reduced by removing moisture from the pellets using a dehumidifying dryer, and can be increased by absorbing the pellets in a humidity-controlled environment.

  The melt viscosity at 180 ° C. of the thermoplastic polyurethane (B) is 200,000 poise or more. When the melt viscosity is less than 200,000 poise, the impact resistance is significantly lowered.

  The melt viscosity at 180 ° C. of the thermoplastic polyurethane (B) is preferably 250,000 poise or more. However, the melt viscosity at 180 ° C. of the thermoplastic polyurethane (B) is preferably 600,000 poise or less. In this case, the dispersibility with the polyacetal resin can be further improved as compared with the case where the melt viscosity at 180 ° C. of the thermoplastic polyurethane (B) exceeds 600,000 poise.

  In addition, in the polyacetal resin composition of this invention, it is preferable that a maleic anhydride containing compound is not contained. That is, the blending amount of the maleic anhydride-containing compound / (the blending amount of the polyacetal resin (A) + the blending amount of the thermoplastic polyurethane (B)) is preferably 0. In this case, since maleic anhydride is not contained, decomposition of the polyacetal resin (A) can be more sufficiently suppressed, and the formaldehyde generation suppressing effect which is the object of the present invention can be more easily realized.

(C) Formaldehyde scavenger The formaldehyde scavenger (C) is for capturing formaldehyde and suppressing the generation of formaldehyde, and is at least one selected from the group consisting of a dihydrazone compound (C1) and a hydrazide compound (C2). Composed of seeds. The compounding quantity of the formaldehyde scavenger (C) with respect to 100 mass parts of polyacetal resin (A) is 0.01-5 mass parts. In this case, compared with the case where the compounding quantity of the formaldehyde scavenger (C) with respect to 100 parts by mass of the polyacetal resin (A) is less than 0.01 parts by mass, the polyacetal resin composition can sufficiently suppress generation of formaldehyde. Moreover, when the compounding quantity of formaldehyde scavenger (C) with respect to 100 mass parts of polyacetal resin (A) is 0.01-5 mass parts, the compounding quantity of formaldehyde scavenger (C) with respect to 100 mass parts of polyacetal resin is 5 masses. The polyacetal resin composition can have more excellent impact resistance as compared with the case of exceeding the part.

  The blending amount of the formaldehyde scavenger (C) with respect to 100 parts by mass of the polyacetal resin is preferably blended at a ratio of 0.1 to 2.0 parts by mass. In this case, compared with the case where the compounding quantity of a formaldehyde scavenger (C) remove | deviates from the said range, a polyacetal resin composition can have the more excellent impact resistance.

(C1) Dihydrazone Compound The dihydrazone compound (C1) blended in the polyacetal resin composition of the present invention is represented by the dihydrazone compound (C1-1) represented by the above general formula (1) and the above general formula (2). The dihydrazone compound (C1-2).

In the general formula (1), R ¹ represents an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.

  The aliphatic hydrocarbon group may be saturated or unsaturated, and may be linear or branched.

  Specific examples of the aliphatic hydrocarbon group include a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group, a pentadecylene group, and a hexadecylene group. Groups, alkylene groups such as heptadecylene group, octadecylene group, nonadecylene group and icosylene group.

  The aliphatic hydrocarbon group is preferably an aliphatic hydrocarbon group having 6 to 12 carbon atoms. In this case, the reactivity between the dihydrazone compound (C1) and formaldehyde becomes higher, and generation of formaldehyde is more effectively suppressed. Further, contamination of the mold during molding can be more sufficiently suppressed.

  The alicyclic hydrocarbon group may be saturated or unsaturated.

  Examples of the alicyclic hydrocarbon group include a cycloalkylene group having 6 to 10 carbon atoms. Examples of the cycloalkylene group include a cyclohexylene group.

  Examples of the aromatic hydrocarbon group include arylene groups such as a phenylene group and a naphthylene group.

  A substituent may be bonded to at least a part of the carbon atoms of the aromatic hydrocarbon group. Examples of the substituent include a halogen group, a nitro group, and an alkyl group having 1 to 20 carbon atoms.

In General Formula (1), R ^{2 to} R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, and at least one of R ² and R ³ is an alkyl group having 1 or 2 carbon atoms. And at least one of R ⁴ and R ⁵ represents an alkyl group having 1 or 2 carbon atoms.

Here, in the general formula (1), when R ² and R ⁴ are ethyl groups, R ³ and R ⁵ are hydrogen atoms, and when R ² and R ⁴ are methyl groups, ³ and R ⁵ are preferably a hydrogen atom or a methyl group.

  In this case, the reactivity between the dihydrazone compound (C1) and formaldehyde becomes higher, and generation of formaldehyde is more effectively suppressed. Further, contamination of the mold during molding can be more sufficiently suppressed.

  Examples of the alkyl group having 1 or 2 carbon atoms include a methyl group and an ethyl group.

  Specific examples of the dihydrazone compound (C1-1) represented by the general formula (1) include, for example, 1,12-bis [2- (1-methylethylidene) hydrazino]]-1,12-dodecanedione, , 12-bis (2-ethylidenehydrazino) -1,12-dodecanedione, 1,12-bis (2-propylidenehydrazino) -1,12-dodecanedione, 1,12-bis [2- (1 -Methylpropylidene) hydrazino] -1,12-dodecanedione, 1,12-bis [2- (1-ethylpropylidene) hydrazino] -1,12-dodecanedione, 1,10-bis [2- (1 -Methylethylidene) hydrazino]]-1,10-decanedione, 1,10-bis (2-propylidenehydrazino) -1,10-decanedione, 1,10-bis (2-propylidenehydrazino) ) -1,10-decanedione, 1,10-bis [2- (1-methylpropylidene) hydrazino] -1,10-decanedione, 1,10-bis [2- (1-ethylpropylidene) hydrazino]- 1,10-decanedione, 1,6-bis [2- (1-methylethylidene) hydrazino] -1,6-hexanedione, 1,6-bis (2-ethylidenehydrazino) -1,6-hexanedione, 1,6-bis (2-propylidenehydrazino) -1,6-hexanedione, 1,6-bis [2- (1-methylpropylidene) hydrazino] -1,6-hexanedione, 1,6- And bis [2- (1-ethylpropylidene) hydrazino] -1,6-hexanedione.

  The dihydrazone compound (C1-1) represented by the general formula (1) may be used alone or in combination of two or more.

In the general formula (2), R ⁸ is an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms in the same manner as R ^1. A hydrocarbon group is shown. R ⁸ may be the same as or different from R ¹ in the general formula (1).

R ⁶ and R ⁷ each independently represents an alicyclic hydrocarbon group having 3 to 12 carbon atoms.

  Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms include a cyclohexylene group.

  Specific examples of the dihydrazone compound (C1-2) represented by the general formula (2) include 1,12-bis (2-cyclohexylidenehydrazino) -1,12-dodecanedione, 1,10- Examples thereof include bis (2-cyclohexylidenehydrazino) -1,10-decanedione and 1,6-bis (2-cyclohexylidenehydrazino) -1,6-hexanedione.

  The dihydrazone compound (C1-2) represented by the general formula (2) may be used alone or in combination of two or more.

  Although the compounding quantity of a dihydrazone compound (C1) is not specifically limited, It is preferable to mix | blend in the ratio of 0.05-3 mass parts with respect to 100 mass parts of polyacetal resin (A). In this case, compared with the case where the compounding quantity of the dihydrazone compound (C1) with respect to 100 mass parts of polyacetal resin (A) is less than 0.05 mass part, generation | occurrence | production of formaldehyde can be suppressed more fully. Moreover, the more excellent impact resistance is obtained compared with the case where the compounding quantity of the dihydrazone compound (C1) exceeds 3 mass parts with respect to 100 mass parts of polyacetal resin (A).

  More preferably, the dihydrazone compound (C1) is blended at a ratio of 0.1 to 1.0 part by mass with respect to 100 parts by mass of the polyacetal resin (A). In this case, compared with the case where the compounding quantity of the dihydrazone compound (C1) with respect to 100 mass parts of polyacetal resin (A) is less than 0.1 mass part, generation | occurrence | production of formaldehyde can be suppressed more fully. Moreover, the more excellent impact resistance is acquired compared with the case where the compounding quantity of the dihydrazone compound (C1) with respect to 100 mass parts of polyacetal resin (A) exceeds 1.0 mass part.

(C2) Hydrazide Compound The hydrazide compound (C2) may be any hydrazide compound having at least one hydrazide group in the molecule. Examples of the hydrazide compound (C2) include polyhydrazide compounds such as a monohydrazide compound, a dihydrazide compound, and a trihydrazide compound. In the present specification, a hydrazide compound having three or more hydrazide groups in the molecule is referred to as a polyhydrazide compound.

  As the monohydrazide compound, either an aliphatic monohydrazide compound or an aromatic monohydrazide compound can be used.

  Examples of the aliphatic monohydrazide compound include propionic acid hydrazide, thiocarbohydrazide, and stearic acid hydrazide.

  Examples of the aromatic monohydrazide compound include salicylic acid hydrazide, 3-hydroxy-2-naphthoic acid hydrazide, p-toluenesulfonyl hydrazide, aminobenzhydrazide, and 4-pyridinecarboxylic acid hydrazide.

  As the dihydrazide compound, either an aliphatic dihydrazide compound or an aromatic dihydrazide compound can be used.

  Examples of the aliphatic dihydrazide compounds include carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide Carbohydrazide), 1,18-octadecanedicarbohydrazide, stearic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, 7,11-octadecadiene-1,18-dicarbohydrazide and the like.

  Examples of the aromatic dihydrazide compound include isophthalic acid dihydrazide, terephthalic acid dihydrazide, 1,5-naphthalenedicarbohydrazide, 1,8-naphthalenedicarbohydrazide, 2,6-naphthalenedicarbohydrazide, 4,4′-oxybis. Examples thereof include benzenesulfonyl hydrazide and 1,5-diphenylcarbonohydrazide.

  Examples of the polyhydrazide compound include aminopolyacrylamide and 1,3,5-tris (2-hydrazinocarbonylethyl) isocyanurate.

  The hydrazide compound (C2) may be used alone or in combination of two or more.

  The hydrazide compound (C2) is not particularly limited, but is preferably composed of at least one selected from the group consisting of a monohydrazide compound and a dihydrazide compound.

  In this case, the hydrazide group (C2) can be more efficiently dispersed in the polyacetal resin (A) than the case where the hydrazide compound (C2) is composed of a hydrazide compound having three or more hydrazide groups in the molecule. The amount of C2) added can be more sufficiently suppressed.

  In particular, the hydrazide compound (C2) is preferably composed of a dihydrazide compound. In this case, generation of formaldehyde can be more sufficiently suppressed as compared with the case where the hydrazide compound is composed of only the monohydrazide compound or the case of being composed of the monohydrazide compound and the dihydrazide compound.

  Although the compounding quantity of a hydrazide compound (C2) is not specifically limited, It is preferable to mix | blend in the ratio of 0.01-1 mass part with respect to 100 mass parts of polyacetal resin (A). In this case, compared with the case where the compounding quantity of the hydrazide compound (C2) with respect to 100 mass parts of polyacetal resin (A) is less than 0.01 mass part, generation | occurrence | production of formaldehyde can be suppressed more fully. Moreover, the more excellent impact resistance is obtained compared with the case where the compounding quantity of the hydrazide compound (C2) with respect to 100 mass parts of polyacetal resin (A) exceeds 1 mass part.

  The hydrazide compound (C2) is more preferably blended at a ratio of 0.3 to 1 part by mass with respect to 100 parts by mass of the polyacetal resin (A). In this case, compared with the case where the compounding quantity of the hydrazide compound (C2) with respect to 100 mass parts of polyacetal resin (A) is less than 0.3 mass part, generation | occurrence | production of formaldehyde can be suppressed more fully.

The relationship between the blending amount of the dihydrazone compound (C1) with respect to 100 parts by mass of the polyacetal resin (A) and the blending amount of the hydrazide compound (C2) with respect to 100 parts by mass of the polyacetal resin (A) is not particularly limited. R represented by the formula (3) is preferably larger than 50% by mass.
R = A _C1 / (A _C1 + A _C2 ) × 100 (3)
(In the formula _{(3), A C1} represents the amount of the polyacetal resin (A) dihydrazone compound for 100 parts by weight _{(C1), A C2} polyacetal resin (A) hydrazide compound for 100 parts by mass of (C2) Represents

  In this case, generation of formaldehyde can be effectively suppressed.

  The R is more preferably 60 to 90% by mass. In this case, generation of formaldehyde can be more effectively suppressed.

  The polyacetal resin composition includes a known antioxidant (for example, triethylene glycol-bis [3 (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate]), a heat stabilizer (for example, melamine), and the like. One or more additives can be added.

  Further, one or more known release agents (polyethylene wax, or release agents such as fatty acid ester-based or silicon-based compounds such as pentaerythritol tetrastearate) may be added to the polyacetal resin composition. it can.

  Furthermore, coloring agents, nucleating agents, plasticizers, fluorescent brighteners, sliding agents, antistatic agents such as polyethylene glycol and glycerin, higher fatty acid salts, UV absorbers such as benzotriazole-based or benzophenone-based compounds, Alternatively, additives such as light stabilizers such as hindered amines can be added as desired.

  Moreover, this invention is a resin molded product formed by shape | molding the polyacetal resin composition mentioned above. That is, the resin molded product of the present invention is composed of the polyacetal resin composition described above.

  The molding method is not particularly limited, and an injection molding method, an extrusion molding method, or the like is used as the molding method.

  As resin molded products, for example, since the generation of formaldehyde during the molding process is suppressed, so-called sick house syndrome measures, automobile interior parts, interior parts such as houses (hot water mixing taps, etc.), clothing parts (fasteners, Belt buckle, etc.), building material applications (pipe, pump parts, etc.), machine parts (gears, etc.)

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example.

Example 1
100 parts by mass of polyacetal resin (A), 20 parts by mass of thermoplastic polyurethane (B) having physical properties (water content, residual NCO amount and melt viscosity) shown in Table 1, and dihydrazone compound (C1) as formaldehyde scavenger (C) ) After mixing 0.1 parts by mass uniformly using a super mixer manufactured by Kawada Seisakusho Co., Ltd., using a twin-screw extruder (PCM-30 manufactured by Ikekai Tekko Co., Ltd., screw diameter 30 mm) according to a conventional method, screw rotation speed After melt-kneading under the conditions of 120 rpm and cylinder set temperature of 190 ° C., the resultant was extruded into a strand and cut with a pelletizer to produce a pellet of a polyacetal resin composition.

  At this time, the trade name “Iupital F20” (manufactured by Mitsubishi Engineering Plastics) was used as the polyacetal resin (A). The melt index (ASTM-D1238 standard: 190 ° C., 2.16 kg) of this polyacetal resin was 10.5 g / 10 min, and the water content was 400 mass ppm.

  At this time, a thermoplastic polyurethane obtained by reacting adipic acid, 1,4-butanediol and 4,4'-diphenylmethane diisocyanate was used as the thermoplastic polyurethane (B).

Further, the water content of the thermoplastic polyurethane (B) and the polyacetal resin (A), the melt viscosity of the thermoplastic polyurethane (B), and the residual isocyanate (NCO) amount of the thermoplastic polyurethane (B) were measured as follows. did.
(1) Water content in thermoplastic polyurethane (B) and polyacetal resin The water content in the thermoplastic polyurethane (B) and polyacetal resin was measured using a Karl Fischer method (ISO 15112) using a moisture measuring device CA-100 manufactured by Mitsubishi Chemical Corporation. / A method).
(2) Melt viscosity of thermoplastic polyurethane (B) Regarding the melt viscosity of thermoplastic polyurethane (B), using a measuring instrument of high and low flow tester CFT500C type (manufactured by Shimadzu Corporation), measuring temperature 180 ° C, load 294N Measured.
(3) Amount of residual isocyanate (NCO) in thermoplastic polyurethane (B) For the amount of residual isocyanate (NCO) in thermoplastic polyurethane (B), JIS K 1603-1 (Method for testing aromatic isocyanate of polyurethane raw material-isocyanate group) The content was measured according to the method described in “How to Obtain Content”).

(Examples 2 to 15 and Comparative Examples 1 to 11)
Compounding amount (parts by mass) of thermoplastic polyurethane (B), compounding amount (parts by mass) of formaldehyde scavenger (C), moisture content in thermoplastic polyurethane (B), residual isocyanate in thermoplastic polyurethane (B) ( A pellet of the polyacetal resin composition was produced in the same manner as in Example 1 except that the amount of NCO) and the melt viscosity at 180 ° C. of the thermoplastic polyurethane (B) were as shown in Tables 1 to 4.

In Tables 1 to 4, nine types of (B-1) to (B-9) were used as the thermoplastic polyurethane (B). In Tables 1 and 2, the following were used as the dihydrazone compound (C1), hydrazide compounds (C2-1) and (C2-2), respectively.
(C1) 1,6-bis [2- (1-methylethylidene) hydrazino] -1,6-hexanedione (C2-1) adipic acid dihydrazide (C2-2) dodecanedioic acid dihydrazide

[Characteristic evaluation]
(1) Effect of suppressing the amount of formaldehyde generated About the effect of suppressing the amount of formaldehyde generated, the amount of formaldehyde generated was measured and evaluated based on the amount of formaldehyde generated.

The amount of formaldehyde generated was measured as follows.
<Fabrication of flat specimen>
First, pellets of the polyacetal resin compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 11 were used at a cylinder temperature of 215 ° C. and a mold temperature of 80 ° C. using an injection molding machine PS-40 manufactured by Nissei Plastic Industry Co., Ltd. Injection molding was performed to prepare a 100 mm × 40 mm × 2 mm flat plate test piece.
<Measurement of formaldehyde generation>
Then, on the day after the day of producing the flat plate test piece, the flat plate test piece was compliant with the method described in German Automobile Manufacturers Association Standard VDA275 (automobile interior parts-determination of formaldehyde emission by the revised flask method). The formaldehyde generation amount was measured by the following method.
(I) First, 50 ml of distilled water was put in a polyethylene container, the lid was closed with the flat plate test piece suspended in the air, and heated in a sealed state at 60 ° C. for 3 hours.
(Ii) After leaving at room temperature for 60 minutes, a flat plate test piece was taken out.
(Iii) The amount of formaldehyde absorbed in distilled water in a polyethylene container was measured by a acetylacetone colorimetric method using a UV spectrometer, and this amount of formaldehyde was defined as the amount of formaldehyde generated. The results are shown in Tables 1-4.

In addition, the criteria of the pass / fail regarding the formaldehyde generation suppression effect was as follows.

・ Formaldehyde generation amount is 2.5 μg / g-POM or less: Pass ・ Formaldehyde generation amount exceeds 2.5 μg / g-POM: Fail

(2) Mold contamination suppression effect The mold contamination suppression effect was evaluated as follows. First, pellets of the polyacetal resin compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 11 were molded using a so-called drop mold using a mini mat M8 / 7A molding machine manufactured by Sumitomo Heavy Industries, Ltd. 3000 shots were continuously formed at a temperature of 200 ° C. and a mold temperature of 80 ° C. After the molding, the state of the inner wall surface of the mold was observed with the naked eye. Here, the standard regarding the mold contamination suppression effect was as follows.

A: There is no mold deposits, and the effect of suppressing mold contamination is very good. B: Almost no mold deposits, and the effect of suppressing mold contamination is very good. C: Mold contamination with little mold deposits. Good suppression effect D: Many mold deposits, poor mold contamination suppression effect

Here, A to C were accepted, and D was rejected. The results are shown in Tables 1-4.

(3) Impact resistance The impact resistance of the polyacetal resin composition was evaluated based on the measured value by measuring the notched Charpy impact strength of the polyacetal resin composition.
The notched Charpy impact strength was measured as follows.
<Preparation of notched Charpy test specimen>
First, pellets of the polyacetal resin compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 11 were injected at a cylinder temperature of 195 ° C. and a mold temperature of 90 ° C. using an injection molding apparatus EC-100S manufactured by Toshiba Machine. Molded to prepare a 4 mm thick ISO No. 1 dumbbell test piece described in JIS K7113.
Next, the dumbbell test piece was cut according to the method described in JIS K7113-1 / 1A to obtain a notched Charpy test piece.
<Measurement of notched Charpy impact strength>
Using the notched Charpy test specimen, the notched Charpy impact strength was measured by an edgewise equilibrium test method in accordance with the method described in ISO-179. The results are shown in Tables 1-4. The acceptance criteria for the notched Charpy impact strength were as follows.

・ Charpy impact strength with notch is 10 kJ / m ² or more: Pass ・ Charpy impact strength with notch is less than 10 kJ / m ² : Fail

  As shown in Tables 1 to 4, it was found that Examples 1 to 15 all met the acceptance criteria in terms of formaldehyde generation suppression effect, mold contamination suppression effect, and impact resistance. On the other hand, it was found that Comparative Examples 1 to 11 did not satisfy the acceptance criteria in terms of formaldehyde generation suppression effect, mold contamination suppression effect or impact resistance.

Therefore, according to the polyacetal resin composition of this invention, it was confirmed that it has the outstanding impact resistance and can fully suppress mold contamination and formaldehyde generation.

Claims (10)

For 100 parts by mass of the polyacetal resin (A), the thermoplastic polyurethane (B) is blended at a ratio of 1 to 120 parts by weight, and the formaldehyde scavenger (C) is blended at a ratio of 0.01 to 5 parts by weight,
The formaldehyde scavenger (C) comprises at least one selected from the group consisting of a dihydrazone compound (C1) and a hydrazide compound (C2),
The dihydrazone compound (C1) is at least one selected from the group consisting of a dihydrazone compound (C1-1) represented by the following formula (1) and a dihydrazone compound (C1-2) represented by the following formula (2). Configured,
A polyacetal resin composition in which the thermoplastic polyurethane (B) has a residual isocyanate amount of 0.10% by mass or less, a moisture content of 3000 ppm by mass or less, and a melt viscosity of 200,000 poise or more at 180 ° C. .

(In the above formula, R ¹ represents an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. R ² to R ⁵ each independently represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, at least one of R ² and R ³ represents an alkyl group having 1 or 2 carbon atoms, and among R ⁴ and R ⁵ At least one represents an alkyl group having 1 or 2 carbon atoms.)

(In the above formula, R ⁸ represents an aliphatic hydrocarbon group having 4 to 20 carbon atoms, an alicyclic hydrocarbon group having 6 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. R ⁶ and R < ⁷ > shows a C3-C12 alicyclic hydrocarbon group each independently.) In Formula (1), the polyacetal resin composition according to claim 1 R ¹ is an aliphatic hydrocarbon group having 6 to 12 carbon atoms. In the general formula (1), when R ² and R ⁴ are ethyl groups, R ³ and R ⁵ are hydrogen atoms,
The polyacetal resin composition according to claim 1 or 2, wherein R ³ and R ⁵ are hydrogen atoms or methyl groups when R ² and R ⁴ are methyl groups.   The polyacetal resin composition according to any one of claims 1 to 3, wherein the dihydrazone compound (C1) is blended at a ratio of 0.05 to 3 parts by mass with respect to 100 parts by mass of the polyacetal resin (A). object.   The polyacetal resin composition as described in any one of Claims 1-4 with which the said hydrazide compound (C2) is mix | blended in the ratio of 0.01-1 mass part with respect to 100 mass parts of said polyacetal resins (A). object. The polyacetal resin composition according to any one of claims 1 to 5, wherein R represented by the following formula (3) is greater than 50% by mass.
R = A _C1 / (A _C1 + A _C2 ) × 100 (3)
(In Formula (3), A _C1 represents the amount of the dihydrazone compound (C1) to 100 parts by mass of the polyacetal resin (A), and A _C2 represents the hydrazide compound (C2 to 100 parts by mass of the polyacetal resin (A)). ))   The polyacetal resin composition according to any one of claims 1 to 6, wherein R is 60 to 90 mass%.   The polyacetal resin composition according to any one of claims 1 to 7, wherein the hydrazide compound (C2) is composed of at least one selected from the group consisting of a monohydrazide compound and a dihydrazide compound.   The polyacetal resin composition according to claim 8, wherein the hydrazide compound (C2) is composed of a dihydrazide compound.   The resin molded product formed by shape | molding the polyacetal resin composition as described in any one of Claims 1-9.