JPH02166151A - Polyoxymethylene composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a polyoxymethylene resin composition having excellent heat resistance stability, oil resistance, hydrolysis resistance, base resistance stability, and mechanical properties.

[Conventional technology]

Polyoxymethylene has a high degree of crystallinity and is known as an engineering plastic with excellent mechanical properties.

However, due to its chemical structure, it is extremely susceptible to oxidative deterioration, and various formulations of heat-resistant stabilizers have been studied.

For example, Japanese Patent Publication No. 46-35980 discloses a technique for improving heat resistance stability by adding and mixing a phenolic antioxidant, alkaline earth metal salts, and tertiary aliphatic amine to polyoxy7-methylene. .

In addition, for the purpose of improving the heat resistance stability of polyoxymethylene, a composition prepared by blending polyvinyl alcohol or a saponified product of Etele 7/me vinyl copolymer with polyoxymethylene is disclosed in JP-A-62-288648.62. -2886
It is disclosed in Publication No. 49.

[Problem to be solved by the invention]

However, since the method disclosed in Japanese Patent Publication No. 46-35980 uses an aliphatic amine with a relatively low molecular weight, it may volatilize in the molten state or the amine itself may decompose. The improvement in heat resistance stability of oxymethylene was insufficient.

Also, the above-mentioned Japanese Patent Application Publication No. 62-288648.62-2886
As disclosed in Japanese Patent Application No. 49, the heat resistance stability of polyoxymethylene was only improved by adding a saponified product of polyvinyl alcohol or ethylene/vinyl acetate copolymer to a very low level.

[Means to solve the problem]

The present inventors have made extensive studies to solve the above problems, and as a result, have discovered the present invention.

That is, in the present invention, (d) 0.001 to 5 hindered phenol having a molecular weight of 300 or more per 100 parts by weight of polyoxymethylene.
Abusive part (b) At least one selected from alkali metal hydroxides, alkaline earth metal hydroxides, carbo/acid alkali metal salts, and carbo/acid alkaline earth metal salts.
001~5MN part (C) At least 5 parts by weight of o, ooi selected from completely saponified products, partially saponified products of ethylene/vinyl acetate copolymer, completely saponified products of polyvinyl acetate, and partially saponified products. It is an m-fatty acid compound.

The hindered phenol used in the present invention is a compound having a phenol structure having an alkyl group having 1 to 6 carbon atoms on at least one side of a hydroxyl group, and has a molecular weight of 300 or more. Specifically, 2,2'-methylenebis(4-methyl-6-1-butylphenol)
Triethylene glycol bis(3-(3-4-butyl-
5-methyl-4-hydroxyphenyl)propionate], pentaerythrityl-tetrakis (3-(3,5-
Di-butyl-4-hydroxyphenyl)propio*
-)), 2. 2-thiodiethylenebis(3-(3
,5-di-1-butyl-4-hydroxyphenyl)propionate), N,N'-hexamethylenebis(
3,5-di-1-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl) Benzene, 1,6-hexanethiol bis(3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propio*-)), 2,4-bis(n-octylthio)
-6-(4-hydroxy-3,5-di-butylanilino)-1,3,5-) riazine, octadecyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
globione), 2,2'-thiobis(4-methyl-6
-t-butylphenol), 3.5-sheet t-butyl-
4-Hydroxybenzylphosphonate-diethyl ester, 3°5-tris(4-1-butyl-3-hydroxy-2,6-dimethylpenzyl)isocyanuric acid,
1.1.3-) Lis(2-methyl-4-hydroxy-5
-t-butylphenyl)butane, 1,1-bis(2-methyl-4-hydroxy-5-t-butylphenyl)butane, N,N'-bis[3-(3,5-di-t-butyl) -4-hydroxyphenyl)globionyl]human didine, 3,9-bis(2-(3-(3-*-butyl-4-hydroxy-5-methylphenyl)propionyloxy)
Examples include 2,2'-methylenebis(4-methyl-6-
t-butylphenol), triethylene glycol-bis(3-(3-t-phthyl-5-methyl-4-hydroxy7xyl)propione-)),! , 6-hexanethiol-bis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), pentaerythrityl-tetrakis(3-(3゜5-di-L-butyl-4-
hydroxyphenyl)propionate), N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), l,3.5-trimethyl-2.4.6 - Tris(3,5-di-t-butyl-
4-Hydroxybenzyl)benzene, 3゜9-bis(2
-(3-(3-t-butyl-4-hydroxy-5-methylphenyl)globionyloxy)-1,1-dimethylethyl)-2゜4,8.10-tetraoxaspiroC5
, 5) Kundecane is preferred.

If the molecular weight is less than 300, a bleeding phenomenon is observed, which impairs the appearance of the molded product and also reduces heat resistance stability, which is not preferred.

Further, the amount added is o, ooi to 5 parts by weight, preferably 0. The amount is 1 to 3 parts by weight, more preferably 0.1 to 2 parts by weight. o, o
If the amount is less than 0 parts by weight, the heat resistance stability of polyoxymethylene will not be sufficient, and if it is more than 5 parts by weight, a bleed phenomenon may be observed or the mechanical properties may deteriorate.

Examples of the alkali metal hydroxide used in the present invention include lithium hydroxide, sodium hydroxide, and potassium hydroxide, with sodium hydroxide and potassium hydroxide being preferred.

Examples of the alkaline earth metal hydroxide used in the present invention include magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide, with magnesium hydroxide, calcium hydroxide, and strontium hydroxide being preferred.

The alkali metal salts of carboxylic acids used in the present invention include sodium acetate, sodium adipate, sodium laurate, sodium stearate, sodium ricinoleate, potassium ricinoleate, sodium lactate,
Sodium montanate, potassium montanate, sodium behenate, potassium behenate, sodium benzoate,
Potassium benzoate, sodium terephthalate, potassium terephthalate, sodium cinnamate, and potassium montanate are preferred.

The alkaline earth metal salts of carboxylic acids used in the present invention include magnesium acetate, calcium acetate, magnesium adipate, calcium adipate, magnesium lafurinate, calcium laurate, magnesium stearate, calcium stearate, strontium stearate, and stearin. Barium acid, magnesium ricinoleate, calcium ricinoleate, barium ricinoleate, magnesium balmitate, calcium balmitate, magnesium lactate, calcium lactate, magnesium montanate, calcium montanate, baricum montanate, magnesium behenate, calcium behenate, behen Potassium acid, magnesium benzoate, calcium benzoate, barium benzoate, magnesium terephthalate, calcium terephthalate, magnesium cinnamate, calcium cinnamate, magnesium tetrapionate, calcium propionate, magnesium butyrate, calcium butyrate 14 Examples include calcium stearate, magnesium stearate, barium stearate, calcium ricinoleate,
Magnesium palmitate, calcium valmitate,
Calcium montanate, magnesium montanate, calcium behenate, magnesium behenate, calcium stearate/calcium valmitate mixture, and magnesium stearate/valmitine finished mag wintersium mixture are preferred.

The aforementioned alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal salts of carboxylic acids, and alkaline earth metal salts of carboxylic acids may be anhydrous salts or may contain water of crystallization.

The amount added is 0.001 to 5 parts by weight, preferably 0.001 to 5 parts by weight, based on 100 parts by weight of polyoxymethylene. The amount is 1 to 3 parts by weight, more preferably 0.1 to 2 parts by weight. 0.00
If it is less than 1 fold, the heat resistance stability of the polyoxymethylene will not be sufficient, and if it exceeds 5 folds, the mechanical properties will deteriorate or the heat resistance stability will decrease.

The completely saponified or partially saponified ethylene/vinyl acetate copolymer used in the present invention and the copolymer of ethylene and vinyl acetate used in the present invention are saponified by alcoholysis reaction, etc. means a polymer that is

Further, chemically modified compounds such as those represented by the general formulas Q() and (I) may also be used.

Further, chemically modified products such as those represented by the general formulas (1) and (2) may also be used.

HCOOH HCOOH 0H.

C1, C0OH Completely saponified polyvinyl acetate (polyvinyl alcohol) and partially saponified polyvinyl acetate used in the present invention have the general formula [F]
, means a polymer represented by Q.

The amount added is o per 100 parts by weight of polyoxymethylene.
, ooi to 5 parts by weight, preferably 0.01 to 3 parts by weight,
More preferably, it is 0.1 to 2 parts by weight.

If the amount is less than 0.001 parts by weight, the heat resistance stability of polyoxymethylene will be insufficient (and if it exceeds 5 parts by weight, the mechanical properties will deteriorate).

The polyoxymethylene used in the present invention is an oxymethylene homopolymer and an oxymethylene consisting mainly of oxymethylene units and containing up to 15% by weight of oxyalkylene units having 2 to 8 adjacent carbon atoms in the main chain. Means a methylene copolymer.

The oxymethylene homopolymer is produced, for example, by introducing substantially anhydrous formaldehyde into an organic solvent containing a basic polymerization catalyst such as an organic amine, polymerizing it, and then acetylating the terminals with acetic anhydride.

Oxymethylene copolymers can also be used, for example, with cyclic oligomers of formaldehyde, such as substantially anhydrous trioxane or tetraoxane, and ethylene oxide, 1,3
- After dissolving or suspending a copolymer component such as dioxolane or 1,3-dioxolane in an organic solvent such as 7-chlorohexane, a Lewis acid catalyst such as boron trifluoride-diethyl ethectate is added. It is produced by polymerizing and decomposing and removing unstable ends.

Alternatively, without using any solvent, in a self-cleaning stirrer, a cyclic oligomer 1 copolymerization component of formaldehyde such as hetrioxane or tetraoxane and a catalyst are introduced, bulk polymerization is carried out, and unstable terminals are further decomposed and removed. do.

Particularly preferably, formaldehyde and/or a cyclic oligomer of formaldehyde and another cyclic ether are polymerized in the presence of a Lewis acid catalyst under substantially anhydrous and solvent-free conditions, and then a hindered amine compound represented by the general formula This is a polymer obtained by adding the same amount of alcohol and stopping the 1-polymer reaction.

(In the formula, R1 represents a hydrogen atom or a monovalent organic residue having 1 to 30 carbon atoms. R2 to R@ represent an alkyl group having 1 to 5 carbon atoms, and may be the same or different. (n represents an integer of 1 or more, and R- represents an n-valent organic residue.) Specifically, the following compounds may be mentioned.

H 0H (fl Yishiri υ- Among these!, 2.2.6.6-pentamethylpiperidine (Z-2), bis(2゜2, 6.6
-tetramethyl-4-piperidinyl)sepacate (G-
1), bis(1,2,2,6,6-pentamethyl-4-
piperidinyl) sebacate (G-2) 1,2,3.
4-Butanetetracarboxylic acid tetrakis (2,2,6,
6-tetramethyl-4-piperidinyl) ester (T-
1), poly((6-(1,1,3,3-tetramethylenebutyl)amino-1,3,5-)riazine-2°4-diyl)((2,2,6,6-tetramethyl -4-piperidinyl)iminoml) (U-1) is preferred.

The hindered amine compound may be added as it is, or may be added as a solution in an organic solvent in order to promote contact with the polymerization catalyst.

Examples of organic solvents include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-hexitine, n-hebutane, and cyclohexane, alcohols such as methanol and ethanol, chloroform, l
, halogenated hydrocarbons such as 2-dichloroethane,
Examples include ketones such as acetone and methyl ethyl ketone.

The hindered amine compound is preferably added in such an amount that the hindered amine structure is present in an amount equal to or more than the mole of the polymerization catalyst used. Although the catalyst deactivation effect can be seen even if the number of moles of the hindered amine structure is less than the number of moles of the polymerization catalyst used, the heat resistance stability of the obtained polymer will decrease slightly, so it may be necessary to It is necessary to adjust the amount added.

The composition of the present invention may contain known colorants (pigments, dyes), conductive agents such as carbon black, flame retardants, reinforcing agents such as glass fibers, carbon fibers, ceramic fibers, aramid fibers, glass beads, glass powder, silica, etc. , a filler such as clay, a nucleating agent such as talc, a lubricant or mold release agent such as ethylene bisstearamide, a plasticizer, an adhesive, a pressure-sensitive adhesive, an antistatic agent, etc. can be optionally contained. In particular, it is preferable to add a nitrogen-containing compound that can react with formaldehyde and capture formaldehyde as a methylol group, since this improves the heat resistance stability.

Examples of stronger nitrogen compounds include amide compounds, urethane compounds, pyridine derivatives, pyrrolidone derivatives, urea derivatives, triazine derivatives, hydrazine derivatives, and amidine compounds. Specifically, N,N-dimethylformamide, N,N -dimethylacetamide, N,N-diphenylformamide, N,N-diphenylacetamide, N,N-diphenylbenzamide, N, N,
N', N'-tetramethyladipamide, silicic acid dianilide, adipic acid dianilide, N-phenylacetanilide, nylon 6, nylon 11. Homopolymers or copolymers of lactams such as nylon 12, dicarboxylic acids such as adipic acid, sebacic acid, decanedicarboxylic acid, and dimic acid, and ethylenediamine, tetramethylenediamine, hexamethylenediamine, metaxylylenediamine, etc. Homopolymers or copolymers of polyamides derived from diamines, polyamide copolymers derived from lactams, dicarboxylic acids, and diamines, polyacrylamide, polymethacrylamide, 5eeN-bis(hydroxymethyl)speramide, poly(r- methyl glutamate), poly B-ethyl glutamate),
Amide compounds such as poly(N-vinyl lactam) and poly(N-vinylpyrrolidone); diisocyanates such as toluene diisocyanate and diphenylmethane diisocyanate; glycols such as 1,4-butanediol; and poly(tetramethylene oxide) glycols;
Polyurethanes derived from polymeric glycols such as polybutylene adipate and polycaprolactone, melamine, benzoguanamine, acetoguanamine, N-butylmelamine, N-phenylmelamine, N,N'-diphenylmelamine, N, N', N'- Triphenylmelamine, N-methylolmelamine, N,N'-dimethylolmelamine, N,N',N'-1-dimethylolmelamine,
2,4-diamino-6-benzyloxytriazine, 2
Triazine derivatives such as t4-diamino-6-butoxytriazine, 2,4-diamino-6-cyclohexyltriazine, melem, melam, N-phenylurea, N,N
'Diphenylurea, thiourea, N-phenylthiourea,
Urea derivatives such as N,N'-diphenylthiourea, ethylene urea, nonamethylene polyurea, phenylhydrazine, diphenylhydrazine, benzaldehyde hydrazone, benzaldehyde semicarbazo/benzaldehyde 1-methyl-1-phenylhydrazone, benzaldehyde thio Semicarbazone, hydrazine derivatives such as hydrazine of 4-(dialkylamino)benzaldehyde, dicyandiamide, guantidi/, guanidine, aminoguanidine, guanine, guanaculine, guanochlor, guanoxane, guanosine, amiloride, N
-Amidino-3-amino-6-chloropyrazinecarboxamide and other amidine compounds, poly(2-vinylpyridine), poly(2-methyl-5-vinylpyridine/)
These include pyridine derivatives such as poly(2-ethyl-5-vinylpyridine), 2-vinylpyridine/2-methyl-5-vinylpyridine copolymer, and 2-vinylpyridine/styrene copolymer.

The amount added is polyoxymethylene 100, which is 0 for the bottom filter section.
．． The amount is from 0.01 to 5 parts by weight, preferably from 0.11 to 3 parts by weight, and more preferably from 0.1 to 2 parts by weight.

0.001! If the amount is less than ijt parts, the heat resistance stability of the polyoxymethylene will not be sufficient, and if it is more than 5 parts by weight, mechanical properties may deteriorate or a bleeding phenomenon may occur.

〔Example〕

The present invention will be explained below with reference to Examples.

In addition, the mechanical properties of the molded products shown in Examples and Comparative Examples, M! , polymer melting point, crystallization temperature, oil resistance, and melting torque reduction rate were measured as follows.

Mechanical properties of molded product (using an injection molding machine with an injection capacity of 5 oz)i
1 nch thick x 1 nch wide tensile test piece, 1 nch
Izot impact test specimens having a thickness of 3/21 nch and a width were injection molded. Using these test pieces, the tensile properties were measured according to ASTM D638, and the Izot impact value with a V-notch was measured according to ASTM D256.

MI (Melt Index) Temperature 190°C according to ASTM D 1238 using pellets dried for 3 hours in a hot air circulation oven at 80°C
, measured at a load of 2.160 f.

Polymer melting point (Tm), crystallization temperature (Tc) Polymer melting point was measured using a DuPont Thermal Analyzer 1090/1091 differential scanning calorimeter by increasing the temperature at a heating rate of lθ°C/■. The crystallization temperature was measured by lowering the temperature at a temperature lowering rate of °C/cm.

Oil Resistance A tensile test piece was immersed in ASTM Mu3 oil heated to 100°C, and taken out after 10, 20, and 30 days to perform a tensile test.

Melt Torque Decrease Rate A 901 pellet was placed in a 100 cc Labo Plast Mill mixer manufactured by Toyo Seiki, and melted and kneaded at 220° C./60 rpm to measure the torque decrease rate. The higher the rate of decline, the more unstable it is thermally.

This test provides a measure of recyclability.

Sufficiently dried rose formaldehyde was thermally decomposed at 150° C. and introduced into the generated formaldehyde gas, cyclohexanol, to produce hemiformal of cyclohexanol. The reaction mixture was distilled to separate hemiformal from the bottom of the column, which was thermally decomposed at 160°C to obtain pure formaldehyde gas.

This formaldehyde gas l x 10-' mol
,/l of tetrabutylammonium globionate at a rate of 100 parts/h into 600 parts of cyclohexane. During this time, the reaction temperature was maintained at 30° C., and the slurry containing the polymer was continuously extracted as needed.

Also, a reaction solvent suitable for the extracted slurry (cyclohexane containing tetrabutylammonium globionate)
was continuously supplied.

The extracted slurry was filtered to remove the polymer, which was then washed with acetone, water, and acetone in this order.

After drying at room temperature, the polymer was poured into acetic anhydride in an amount 10 times the amount of the polymer, sodium acetate corresponding to 0.1% by weight of acetic anhydride was added, and the mixture was heated and stirred at 39° C. for 5 hours. After the reaction mixture was cooled to room temperature, the precipitated polymer was separated. After washing with water, acetone, and water in this order, it was dried with hot air at 120°C.

The melting point of this polymer is 175°C, the crystallization temperature is 151°C,
M I = 15.6 @ Manufacture of polyoxymethylene POM-2 Two-shaft kneader with 26 convex lens-shaped paddles per shaft (301111φ, L/D = 10.2)
tl: Polymerization was carried out by continuously supplying the following raw materials.

The polymerization temperature is approximately 8 ℃ by passing hot water through the outer jacket.
The temperature was controlled at 0°C, and the rotation speed was set at 175 rpm. The acetal as a molecular weight regulator is trioxa/
Boron trifluoride/diethyl etherate as a polymerization catalyst was dissolved in benzene and supplied to the kneader.

In addition, a premixing zone (mixing in the pipe) at 30° C./retention time of 2 minutes was provided so that 1,3-dioxolane and the catalyst solution were premixed immediately before being supplied to the kneader. The polymer powder thus obtained was poured into a 5% ammonia aqueous solution and stirred. The polymer powder was taken from house to house, washed in the order of water, acetone, and water, then poured into a 15% ammonia aqueous solution, and heated and stirred at 150° C. for 4 hours in an autoclave. After cooling to room temperature, the precipitated polymer is separated from each other,
Washed with water, acetone, and water in this order. It was further dried for 3 hours in a hot air circulation oven at 80°C. The melting point of this polymer is L69°C, the crystallization temperature is 147°C, and MI=9. It was Q.

Production of polyoxymethylene POM-3 0.27 parts by weight of bis(1,2,2,6 ,6-bentamethyl-4-piperidinyl)cepa)y-to(C1ba-Geigy
A solution of ``5anol LS 765'') dissolved in 2 parts by weight of benzene was added, and the catalyst was deactivated by stirring and mixing in a Henschel mixer for 10 minutes. Furthermore, a hot air circulation oven set at 80°C was used. It was dried inside for 3 hours.

The melting point of this polymer is 168°C, the crystallization temperature is 145°C, and the M
I=g. It was 7.

Examples 1 to 23 Polyoxymethylene POM-1 to PO produced in reference examples
Various additives were added to M-3 at the compounding ratios shown in Table 1, and the mixture was melt-kneaded using a vented twin-screw extruder with a diameter of 45 mm and L/D = 3L5. The crosstalk temperature was set at 220 to 240°C, and the degree of pressure reduction was 40 to 50 Hp. Table 2 shows the results of measuring the physical properties of the obtained composition.

Comparative Examples 1 to 18 Polyoxymethylene POM-1, PO produced in Reference Examples
Each coating additive was added to M-3 at the compounding ratio shown in Table 3, and the resulting mixture was 450φ, L/D = 31. ．． The mixture was melt-kneaded using a vented twin-screw extruder No. 5. Crosstalk temperature is 220-240℃
The degree of pressure reduction was set to 40 to 50 flHy. Table 4 shows the results of measuring the physical properties of the obtained composition.

The abbreviations or trade names of additives shown in Tables 1 and 3 represent the following compounds.

Ir 1010: Irganox 1010 Antioxidant manufactured by Chipa Geigy Pentaerythrityl-tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate) Ir 245:
Irganoz 245 Antioxidant manufactured by Ciba Geigy Triethylene glycol-bisl:3-(1-t-
Butyl-5-methyl-4-hydroxyphenyl)propiot)Ir 259: Irganoz 25
9 Antioxidant manufactured by Ciba Geigy 1.6-hexanethiolubis(3-(3,5-di-1-butyl-4-
Hydroxyphenyl) propionate) G A -+3
Q: Sumilizer GA-80 Juju Chemical antioxidant 3,9-bis(2-(3-(3-1-
Butyl-4-hydroxy-5-methylphenyl)globionyloxy)-1゜1-dimethylethyl)-2,4,
8,10-Tetraoxaspiro C5,5) Undecane Eval EP-E105: Ri? Made of ethylene/vinyl alcohol copolymer, melting point 164°C, M I = s
, 5 Demilan D-229: Shikinichi Yakuhin Co., Ltd. Partially saponified product of ethylene/vinyl acetate co-electrolyte Melting point: 95°C, M I = 72 Dumilan C-1550: Shikinichi Yakuhin Co., Ltd. Ethylene/
Modified product of partially saponified vinyl acetate co-benefits melting point 73°C, M I = 15.0 From Examples 1 to 4.7 to 10.13 to 20, hindered phenol, alkali metal or alkaline earth was added to polyoxymethylene. It can be seen that the resin composition containing metal salts and a saponified product of polyvinyl acetate polymer is superior in heat resistance stability and oil resistance. Furthermore, it can be seen that the heat resistance stability and oil resistance are excellent regardless of the type of hindered phenol, the type of alkali metal or alkaline earth metal salt, and the type of saponified polyvinyl acetate polymer.

From Examples 5 to 6, 11 to 12, and 20 to 23, it can be seen that the melting torque stability is improved by further adding and blending a nitrogen-containing compound (formaldehyde scavenger).

Examples 13 to 23 show that a particularly stable resin composition can be obtained by using the polymer POM-3 obtained by deactivating the catalyst with a hindered amine compound as a pace polymer.

Comparative example 1? , 13, it can be seen that if hindered phenol is not added, not only the initial physical properties are extremely deteriorated, but also the oil resistance is extremely low.

Comparative Example 2.8.14 shows that melt torque stability and oil resistance deteriorate if alkali metal or alkaline earth metal salts are not added.

From Comparative Example 3.9.15, it is clear that if the saponified product of polyvinyl acetate-based polymer is not added, the melt torque stability and oil resistance deteriorate.

Comparative Example 4.10.16 shows that when a large amount of hindered phenol is added, the initial physical properties and oil resistance deteriorate. A bleed phenomenon was also observed.

Comparative Examples 5, 11, and 17 show that when a large amount of alkali metal or alkaline earth metal salts is added, the initial Izod impact value, melt torque stability, and oil resistance decrease.

Comparative Example 6.12.18 shows that when a large amount of saponified polyvinyl acetate polymer is added, the initial tensile strength and oil resistance decrease.

〔Effect of the invention〕

Since the resin composition of the present invention has excellent mechanical properties, thermal stability, and oil resistance, it can be used in a wide range of applications such as automobile parts and mechanical mechanism parts.

Patent application Daitoshi Co., Ltd.

Claims (1)

[Claims] (1) (a) based on 100 parts by weight of polyoxymethylene
Hindered phenol with molecular weight 300 or more 0.001~
5 parts by weight (b) 0.001 to 5 parts by weight of at least one selected from alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal salts of carboxylic acids, and alkaline earth metal salts of carboxylic acids ( c) completely saponified product of ethylene/vinyl acetate copolymer,
A resin composition containing 0.001 to 5 parts by weight of at least one selected from partially saponified products, completely saponified products of polyvinyl acetate, and partially saponified products.