JP3270017B2 - Polyacetal resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyacetal resin composition having improved environmental stress cracking (hereinafter referred to as "ESCR") and improved physical properties of a weld portion while maintaining the processability of a polyacetal resin molded product. It is about.

[0002]

2. Description of the Related Art Polyacetal resins are well-balanced in mechanical strength, impact resistance and slidability, and are easy to process. It is widely used mainly for parts, automobile parts and other mechanical parts. Many polyacetal resin molded products are components that may have distortion remaining in the molded product itself by insert molding or the like, or components that are subjected to continuous or repeated stress load in the inside handle of automobiles, gears of electronic devices, etc. . In addition, most of these polyacetal resin molded products have a weld portion because they are molded by a multipoint gate. As described above, as the field in which the polyacetal resin is used is expanded, the environment in which the polyacetal resin is used is various, and further improvement in the performance as a material is required.

[0003] Incidentally, although ESCR in the present invention is one of important properties, there is no generally known method for improving the ESCR of a polyacetal resin. In addition, it can be inferred from the literature on improvement of other resins that it can be improved by increasing the molecular weight of the polyacetal resin.However, in increasing the molecular weight of the polyacetal resin, the fluidity during injection molding deteriorates, for example, when multiple pieces are taken. In addition, there is a problem that molding workability is inferior in thinning and the like. Therefore, a formulation close to the polyacetal resin composition of the present invention has been known so far, and will be described below.

A method of adding a fatty acid metal salt to a polyacetal resin is disclosed in JP-B-43-006101, JP-B-46-035980, and JP-B-47-004943.
JP, JP-B-47-010531, JP-B-48
-017378, JP-A-49-066747, JP-A-49-104940, and JP-B-55-0
No. 21778, Japanese Patent Publication No. 55-022508,
JP-A-57-102943, JP-A-59-096
157, JP-A-59-179563, JP-A-59-179654, JP-A-59-179655, JP-A-59-179656, and JP-A-59-17.
9657, JP-A-59-179658, JP-A-59-179659, JP-A-60-08348, JP-B-60-057484, and JP-B-62.
004422, JP-B-62-058387, JP-A-63-260949, JP-A-2-06
No. 7352, JP-A-2-166151, JP-A-2-209944, JP-A-3-014857, JP-A-3-014859, JP-A-3-03
9351, JP-A-3-048819, JP-A-4-063857, JP-A-5-156118, JP-A-5-279550, JP-A-6-00
9854, JP-A-7-003117, JP-A-7-026111, JP-A-7-033953, JP-A-7-173368, JP-A-7-17
No. 3,369, JP-A-7-196889, JP-A-7-248162, JP-A-7-331028, WO97-12937, Patent 267784
No. 9 and other publications.

[0005] These patent publications do not disclose the incorporation of a difatty acid alkaline earth metal salt (B) produced by mixing two or more fatty acids into a polyacetal resin. Also, the above-mentioned JP-A-2-067352, JP-A-2-166151, and Japanese Patent No. 26778 are described.
No. 49 describes a resin composition containing at least one selected from alkaline earth metal salts of fatty acids, and describes in Examples that calcium stearate and calcium palmitate are used in combination. A difatty acid alkaline earth metal salt produced using only one kind of fatty acid is used, and there is no description of producing a difatty acid alkaline earth metal salt (B) by using two or more kinds of fatty acids in combination. .

The above-mentioned JP-A-59-179653 to JP-A-59-179659 and JP-B-62-0044 are disclosed.
No. 22, JP-A-3-039351, suggests the use of a combination of an alkaline earth metal salt of a difatty acid and a fatty acid, but there is no example, and only the possibility is shown. Naturally, the combined use of the specific difatty acid alkaline earth metal salt (B) and the fatty acid (C) according to the present invention simultaneously and remarkably improves the ESCR of the polyacetal resin molded article and the property improvement of the weld portion. It is not described to do.

On the other hand, when molding with a multipoint gate, etc.
Many of them have a weld portion in the molded product, and the physical properties of the weld portion of the polyacetal resin molded product are one of the important physical properties. For example, when a molded product having a weld portion is aged at a high temperature, the physical property value of the weld portion shows a much lower value than the physical property value of the non-weld portion, and the physical property retention of the weld portion is considered in product design. is important. However, it is a reality that improvement of the physical properties of a weld portion of a polyacetal resin molded product has not yet been achieved.

As a method for improving the heat aging resistance of a polyacetal resin, it is common to add a fatty acid metal salt to the above-mentioned polyacetal resin. For example, Japanese Patent Publication No. 55-022508 and Japanese Patent Laid-Open No. 2-20
No. 9944 and Japanese Patent Laid-Open No. 7-003117,
It is disclosed that a fatty acid metal salt is added to a polyacetal resin to improve heat aging resistance. However, these methods improve the heat aging resistance of the non-weld part, but the physical properties of the weld part after aging are as follows:
It is not sufficiently satisfactory compared to the physical properties of the non-weld part.

On the other hand, a polyacetal resin obtained by adding a fatty acid ester and a fatty acid to a polyacetal resin is also disclosed. For example, a polyacetal resin composition obtained by adding a fatty acid ester derived from a fatty acid and a polyhydric alcohol to a polyacetal resin is disclosed in
JP-A-3-031900, JP-A-60-104153, JP-A-2-263856, JP-B-5-01
8864, JP-B-5-035186, JP-A-6-107900, JP-A-6-293857, JP-A-7-018157, and Patent No. 2522
No. 302 discloses this.

Also, polyacetal resin compositions obtained by adding a fatty acid ester having a hydroxyl group to a polyacetal resin are disclosed in JP-A-50-046756, JP-B-56-052940, and JP-A-57-1287.
40, JP-A-6-293856, JP-A-7
-011101. A polyacetal resin composition obtained by adding a fatty acid ester and a fatty acid metal salt to a polyacetal resin is described in JP-B-63-086.
02297, JP-A-4-063857, JP-A-7-173368, JP-A-7-196889
And Japanese Patent Application Laid-Open No. 7-331028. However, in any of the above methods, the physical properties of the weld portion when the polyacetal resin molded product is subjected to the heat aging resistance test are not sufficiently satisfactory as compared with the physical properties of the non-weld portion, and there is an urgent need to improve these problems. Is desired.

[0011]

In recent years, the use of polyacetal resins has become widespread, and polyacetal resins are degraded by acid rain, acids generated in minute amounts from heating of resins containing halogen groups, and the like. I know that there are things. The present invention provides E
It is an object of the present invention to provide a polyacetal resin composition having improved SCR, particularly ESCR in an acidic atmosphere, and at the same time, improved physical properties of a weld portion before and after a heat aging test.

[0012]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventor has found that polyacetal resin (A) has:
By adding the fatty acid (C) in addition to the difatty acid alkaline earth metal salt (B) produced by mixing two or more fatty acids, the physical properties of the ESCR and the weld portion are simultaneously and markedly improved. Heat aging test by adding a fatty acid diester compound (D) represented by the following general formula (I) and a fatty acid monoester compound (E) represented by the following general formula (II). The inventors have found that the physical properties of the welded portion after the above can be improved, and have reached the present invention.

Formula (I) R ¹ —COO (R ³ O) n-COR ² (R ¹ and R ² are substituted with an alkyl or alkenyl group having 9 to 35 carbon atoms or one hydroxyl group. In the alkyl or alkenyl group, R ¹ and R ² may be the same or different, and R ³ O has 2 to 6 carbon atoms.
Represents an alkylene glycol unit. Also, n is 1
Represents an integer of ~ 70. The general formula (II): R ⁴ —COO (R ⁵ O) m—H (where R ⁴ is an alkyl group or alkenyl group having 9 to 35 carbon atoms, or the alkyl group or alkenyl substituted with one hydroxyl group) R ⁵ O represents an alkylene glycol unit having 2 to 6 carbon atoms, and m represents 1 to
Represents an integer of 70. )

That is, the present invention relates to (1) (A) 100 parts by weight of a polyacetal resin, and (B) an alkaline earth metal salt of a difatty acid produced by mixing two or more fatty acids. 1.0 parts by weight, and (C) fatty acid 1 × 1
0 ^-6 ~1 × 10 ^-1 parts by weight of the polyacetal resin composition obtained by blending, (2) fatty acids (C) and the weight ratio of di-acid alkaline earth metal salt (B) is C / B = 0. 1/100
(1) The polyacetal resin composition according to (1) or (2), wherein the fatty acid (C) is a combination of two or more fatty acids. Composition,

(4) The fatty acid (C) is a combination of at least one fatty acid having an odd carbon number and at least one fatty acid having an even carbon number, and the total number of fatty acids having an odd carbon number. The weight ratio of (C1) to the total number of fatty acids having an even carbon number (C2) is C1 / C2 = 0.1 / 99.9-
(1) The polyacetal resin composition according to (1), (2) or (3), wherein the fatty acid used for the fatty acid (C) is a difatty acid alkaline earth metal salt The polyacetal resin composition according to (1), (2), (3) or (4), which is at least one of the fatty acids used for the production of (B), (6) alkaline earth metal salt of difatty acid (B )) Is a combination of at least one fatty acid having an even carbon number and at least one fatty acid having an even carbon number, and the total amount of fatty acids having an even carbon number (B1) And the weight ratio of the total number of fatty acids having an odd carbon number (B2) is B1 / B2 = 0.1 / 99.9-
(1), (2) in the range of 99.9 / 0.1,
(3) The polyacetal resin composition according to (4) or (5),

(7) The alkaline earth metal salt of difatty acid (B) has a metal component of calcium, and the fatty acid used for producing the alkaline earth metal salt of difatty acid (B) is lauric acid, tridecylic acid, myristic acid. 2 selected from the group consisting of acids, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, and behenic acid
More than species (1), (2), (3), (4), (5)
Or the polyacetal resin composition according to (6),
(8) The polyacetal resin composition according to (1),
(D) a polyacetal resin composition obtained by adding a fatty acid diester compound represented by the following general formula (I) and (E) a fatty acid monoester compound represented by the following general formula (II): ^{1 -COO (R 3 O) n} -COR 2 (R 1, R 2 the alkyl group substituted alkyl group of 9-35 carbon atoms, or an alkenyl group, or one hydroxyl group, or an alkenyl group, R ¹ and R ² may be the same or different, and R ³ O has 2 to 6 carbon atoms.
Represents an alkylene glycol unit. Also, n is 1
Represents an integer of ~ 70. The general formula (II): R ⁴ —COO (R ⁵ O) m—H (where R ⁴ is an alkyl group or alkenyl group having 9 to 35 carbon atoms, or the alkyl group or alkenyl substituted with one hydroxyl group) R ⁵ O represents an alkylene glycol unit having 2 to 6 carbon atoms, and m represents 1 to
Represents an integer of 70. )

(9) The fatty acid diester compound (D)
And the total amount of the fatty acid monoester compound (E) is 0.0% based on 100 parts by weight of the polyacetal resin.
0.5 to 3.0 parts by weight, and the weight ratio of the fatty acid diester compound (D) to the fatty acid monoester compound (E) is (D) / (E) = 99.9 / 0.1 to 0.1 / 99.9
The polyacetal resin composition according to (8), wherein (1)
0) The amount of formaldehyde gas generated when the polyacetal resin is heated at 230 ° C. for 50 minutes in a nitrogen atmosphere is 500 ppm or less (1) (2) (3) (4)
(5) (6) (7) molded using the polyacetal resin composition according to (8) or (9), or (11) the polyacetal resin composition according to any one of (1) to (10). Gear molding.

The present invention relates to a polyacetal resin (A)
By mixing a difatty acid alkaline earth metal salt (B) produced by mixing two or more fatty acids and a specific amount of the fatty acid (C), surprising E is maintained while maintaining moldability.
It has been found that the improvement of the SCR and the improvement of the weld portion can be achieved at the same time. Further, as the fatty acid (C), two or more fatty acids, particularly fatty acids having even and odd carbon atoms, are used in combination, and / or difatty acid. It has been found that the physical properties of the ESCR and the weld portion are further improved by using the even-numbered and odd-numbered fatty acids in combination as the raw material of the alkaline earth metal salt (B). In addition, it has been found that by further blending a specific fatty acid diester compound (D) and a fatty acid monoester compound (E), the weld portion after the surprising heat aging test is improved, and the present invention has been completed. is there. Hereinafter, the configuration of the present invention will be described in detail.

The polyacetal resin (A) referred to in the present invention refers to a substantially oxy resin produced from a cyclic oligomer such as a formaldehyde monomer or its trimer (trioxane) or tetramer (tetraoxane). Polyoxymethylene homopolymer obtained by performing terminal stabilization on an oxymethylene homopolymer composed of methylene units, and the above raw materials, ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolan, 1,4-butanediol, and glycol End stabilization of an oxymethylene-oxyalkylene copolymer containing 0.1 to 20% by weight of an oxyalkylene unit having 2 to 8 carbon atoms produced from a comonomer such as a cyclic formal such as a formal of diglycol or a formal of diglycol. The port obtained by performing the processing It can be mentioned oxymethylene copolymers.

Further, the polyacetal resin in the present invention may be an oxymethylene-oxyalkylene copolymer having a branched molecular chain, or a polyoxymethylene (POM) block of 50% by weight or more and a repeating unit of oxymethylene. An oxymethylene-based block copolymer composed of 50% by weight or less of a polymer block different from POM containing 50% by weight or more may be used. Preferably, it is a polyoxymethylene copolymer consisting of an oxymethylene-oxyalkylene made using 1,3-dioxolane as a comonomer.

The method for producing the polyacetal resin that can be used in the present invention is not particularly limited.
For example, it can be manufactured by a conventionally known method such as US Pat. No. 2,998,409. For example,
In the case of copolymerization, it can be obtained by copolymerizing trioxane and a cyclic ether as a comonomer, treating the obtained polymer with a twin-screw extruder or the like, and stabilizing the terminal. The polymerization method is carried out by bulk polymerization, batch type,
It is possible by any of the continuous methods. As a batch type polymerization apparatus, a reaction vessel equipped with a stirrer can be generally used. As the continuous type, a self-cleaning type mixer such as a co-kneader, a twin-screw type continuous extrusion kneader, a twin-screw paddle type continuous mixer or the like can be used. The polymerization conditions are
It is carried out in a temperature range of 60C to 200C under normal pressure.

As the polymerization catalyst, boron trifluoride, boron trifluoride hydrate, and a coordination complex compound of an organic compound containing an oxygen atom or a sulfur atom and boron trifluoride are generally used. Used as a solution in organic solvents. Since the obtained polymer contains an active polymerization catalyst, it is desirable to deactivate the polymerization catalyst. The method of deactivating the polymerization catalyst is as follows.
The reaction is performed in an aqueous solution containing a basic substance or in an organic solvent. As another deactivation method, a method in which a basic substance is added to the polyacetal resin before terminal stabilization, and deactivation is performed in a molten state using an extruder can also be used. Examples of the basic substance used for deactivation include hindered amines, ammonia, nitrogen-containing compounds such as triethylamine and tributylamine, and the like.

The method for stabilizing the terminal of the polymer after the deactivation of the polymerization catalyst includes, for example, (1) a step of injecting a basic substance into a polymer in a molten state, followed by kneading, and (2) a step of kneading the basic substance. A volatile component is separated from the molten polyacetal resin by using a twin screw extruder or the like capable of continuously performing an operation for end stabilization consisting of at least two steps of releasing the vapor of the substance and free formaldehyde. Can be used to stabilize the terminal. Examples of the basic substance include nitrogen-containing compounds such as ammonia, triethylamine, and tributylamine. Further, water may coexist with the basic substance.

Preferred polyacetal resins include those having a formaldehyde emission of 500 ppm or less. The amount of formaldehyde gas generated from the polyacetal resin can be determined by the following method.
The terminal-stabilized polyacetal resin is placed in an aluminum container, heated and melted at 230 ° C. for 50 minutes under a nitrogen atmosphere, and the formaldehyde gas generated at that time is absorbed in an aqueous sodium sulfite solution and titrated with 0.01 N sulfuric acid. Then, the amount of formaldehyde generated is calculated from the titration amount of sulfuric acid.

The difatty acid alkaline earth metal salt (B) in the present invention is a fatty acid having a chain structure among carboxylic acids having 10 to 36 carbon atoms and one carboxyl group (RCOOH). And a difatty acid alkaline earth metal salt (B) produced by mixing two or more of these with an alkaline earth metal compound. The metal component used for these difatty acid alkaline earth metal salts (B) is one or two selected from beryllium, calcium, magnesium, barium, zinc, aluminum, strontium, and radium.
A combination of more than one species. Among these metals, calcium is particularly preferred for improving the physical properties of the ESCR and the weld.

Also, the alkaline earth metal salt of difatty acid (B)
May be any of saturated fatty acids, unsaturated fatty acids, and fatty acids substituted with a hydroxyl group, preferably saturated fatty acids. Fatty acids used include capric acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid,
Heptadecyl acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, rig Roh serine acid, cerotic acid, montanic acid, melissic acid, Seropurasuchin acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, erucic acid, brassidic acid, Sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearic acid,
12-hydroxydodecanoic acid, 3-hydroxydecanoic acid, 16-hydroxyhexadecanoic acid, 10-hydroxyhexadecanoic acid, 12-hydroxyoctadecanoic acid,
Examples thereof include 10-hydroxy-8-octadecanoic acid and dl-erythro-9,10-dihydroxyoctadecanoic acid. Among these fatty acids, preferably lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid,
Arachiic acid and behenic acid, particularly preferably palmitic acid, heptadecylic acid and stearic acid.

The alkaline earth metal salt of difatty acid (B) used in the present invention must be produced by mixing two or more fatty acids. As the alkaline earth metal salt of difatty acid, a mixture of two or more kinds of metal salts (for example, calcium dipalmitate, calcium diheptadecylate, calcium distearate, etc.) composed of the same fatty acid may be used (Comparative Example 7 of the present invention). , 8,1
2. ) The effect of improving the physical properties of the ESCR and the weld portion is low. For this reason, as the difatty acid alkaline earth metal salt (B), those produced by mixing two or more kinds of fatty acids are composed of not only metal salts of the same kind of fatty acid but also fatty acids of different carbon numbers. Contains metal salts (eg, monopalmitic acid-calcium monoheptadecylate, monopalmitic acid-calcium monostearate, monoheptadecylic acid-calcium monostearate, etc.), thereby improving the properties of the ESCR and welds. I guess it is big.

The fatty acids used as raw materials of the difatty acid alkaline earth metal salt (B) include fatty acids having an even number of carbon atoms (B1: for example, stearic acid and the like) and fatty acids having an odd number of carbon atoms (B2). : For example, heptadecylic acid) is more preferably used in combination.
1 / B2 = 99.9 / 0.1 to 0.1 / 99.9 weight ratio, more preferably B1 / B2 = 99/1 to 1/9
9 weight ratio. The fatty acid having an odd number of carbon atoms as used herein is, for example, a fatty acid obtained from beef tallow before purification, is subjected to gas chromatography / mass spectrometry (GC-MS: HP5890 + HP5971 manufactured by Hewlett-Packard Company).
A, Column used: DB-1 {inner diameter = 0.25 mm, film thickness = 0.25 μm, length = 30 m}, injection part temperature = 250
° C, detector temperature = 280 ° C, column bath temperature = 100 ° C →
{10 ℃ / min} → 350 ℃ × 50min, carrier gas = H
e (50 ml / min split ratio: 30 °), it can be confirmed that an odd number of fatty acids are present as shown in FIG.

The purity of these odd-numbered fatty acids is 95% by weight or more using size exclusion liquid chromatography (LC-GPC: manufactured by Nippon Kagaku Kogyo Co., Ltd., LC-908, column used: Shodex, H-2001 + H-2002). It was confirmed that separation was possible. The method for producing a difatty acid alkaline earth metal salt (B) is not particularly limited, and may be, for example, a neutralization reaction between a fatty acid and a metal hydroxide, a metathesis reaction between a fatty acid and a metal chloride, The crude difatty acid alkaline earth metal salt obtained by the neutralization reaction between the fatty acid and the metal oxide is further subjected to a washing treatment and a drying treatment, whereby the desired difatty acid alkaline earth metal salt (B ) Can be obtained.

In addition, the metal compound substantially unreacted is 50
0 ppm or less of a difatty acid alkaline earth metal salt (B)
Is preferred. As for the unreacted metal compound in the obtained difatty acid alkaline earth metal salt (B), the difatty acid alkaline earth metal salt (B) is subjected to ultrasonic treatment, and the metal component extracted in the filtrate is subjected to electric conductivity detection. It can be determined by converting the obtained quantitative value into a raw material metal hydroxide, metal oxide or metal chloride. The addition amount of the difatty acid alkaline earth metal salt (B) is determined based on the polyacetal resin 10
0.001 to 1.0 part by weight, preferably 0.01 to 0.5 part by weight, based on 0 part by weight. When the amount of the difatty acid alkaline earth metal salt (B) added is less than 0.001 part by weight, the effect of improving the physical properties of the ESCR and the weld portion of the molded article decreases, and the amount added is 1.0% by weight. If the amount exceeds the part, the effect of improving the physical properties of the ESCR and the weld part is reduced, and the heat stability and the color tone of the molded piece are deteriorated.
As for unreacted metal oxides, hydroxides and chlorides in the difatty acid alkaline earth metal salt (B), the thermal stability is 500 ppm or less based on the difatty acid alkaline earth metal salt (B). And the color tone of the molded piece.

The fatty acid (C) referred to in the present invention is 10 to 3
Fatty acids with 6 carbon atoms. These fatty acids (C) may be any of saturated fatty acids, unsaturated fatty acids, and fatty acids substituted with a hydroxyl group, but are preferably saturated fatty acids. Examples are capric acid, lauric acid, tridecyl acid, myristic acid, pentadecyl acid, palmitic acid, heptadecyl acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, rig Roh serine acid, cerotic acid, montanic acid, melissic acid , Celloplastic acid, undecylenic acid, oleic acid, elaidic acid, setreic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearolic acid, 12-hydroxydecanoic acid, 3-hydroxy Decanoic acid, 16-hydroxydecanoic acid, 10-hydroxydecanoic acid, 12-hydroxyoctadecanoic acid and the like can be mentioned. Among these fatty acids (C), lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid and behenic acid are preferred.

In the present invention, these fatty acids (C)
Can be used alone or in combination of two or more,
It is preferable to use two or more fatty acids (C) in combination because the physical properties of the ESCR and the weld portion are further improved. Particularly preferably, one or more fatty acids having an odd number of carbon atoms (C1: represents, for example, heptadecylic acid, etc.) and one or more fatty acids having an even number of carbon atoms (C2: represents, for example, stearic acid, etc.) It is to use together. The ratio of combined use is C1 / C2 = 0.1 / 99.9-99.9 / 0.1.
(Weight ratio), preferably C1 / C2 = 1 / 99-
99/1 (weight ratio). In addition, the fatty acid (C) used is a difatty acid alkaline earth metal salt (B) used in combination.
The same as at least one of the fatty acids that are the raw materials for
It is preferable for improving the physical properties of the SCR and the weld portion.

The amount of the fatty acid (C) to be added is 1 × 10 ^-6 to 1 × 10 ^-1 part by weight based on 100 parts by weight of the polyacetal resin. Preferably, C / B = 0.1 / 100 to 10/10 with respect to the difatty acid alkaline earth metal salt (B).
It is a range represented by 0 (weight ratio). Further, it is preferable to use the difatty acid alkaline earth metal salt (B) and the fatty acid (C) in a premixed manner in order to improve the physical properties of the ESCR and the weld portion. The premixing method may be appropriately selected by a known method, and is not particularly limited. The effect of the combined use of the fatty acid (C) and the difatty acid alkaline earth metal salt (B) as described above is not clear. It is presumed that distortion is small.

The fatty acid ester compounds referred to in the present invention include those having 1 carbon atom represented by the following general formulas (I) and (II).
A fatty acid diester compound (D) and a fatty acid monoester compound (E) obtained from a saturated or unsaturated fatty acid of 0 to 36, a fatty acid substituted with a hydroxyl group, and an alkylene glycol having 2 to 6 carbon atoms. General formula (I) R ¹ -COO (R ³ O) n-COR ² (R ¹ and R ² are an alkyl group having 9 to 35 carbon atoms, or an alkenyl group, or an alkyl group substituted with one hydroxyl group. Or an alkenyl group, R ¹ and R ² may be the same or different, and R ³ O has 2 to 6 carbon atoms.
Represents an alkylene glycol unit. Also, n is 1
Represents an integer of ~ 70. The general formula (II): R ⁴ —COO (R ⁵ O) m—H (where R ⁴ is an alkyl group or alkenyl group having 9 to 35 carbon atoms, or the alkyl group or alkenyl substituted with one hydroxyl group) R ⁵ O represents an alkylene glycol unit having 2 to 6 carbon atoms, and m represents 1 to
Represents an integer of 70. )

These fatty acid ester compounds are a fatty acid diester compound (D) and a fatty acid monoester compound (E), and the total amount of the fatty acid diester compound (D) and the fatty acid monoester compound (E) is 100%. 0.005 to 3 parts by weight.
0 parts by weight, and the weight ratio of the fatty acid diester compound (D) to the fatty acid monoester compound (E) is (D) / (E)
= 99.9 / 0.1-0.1 / 99.9. Preferably 0.00.0 parts by weight of polyacetal resin
1 to 1.0 part by weight. The weight ratio of the fatty acid diester compound (D) to the fatty acid monoester compound (E) is preferably (D) / (E) = 99.9 / 0.1 to 50/50, more preferably 99.9 / 0.1. ９０90/10. When the total amount and the weight ratio of the fatty acid diester compound (D) and the fatty acid monoester compound (E) are out of this range, the physical properties of the weld portion after the heat aging test of the polyacetal resin molded product are sufficiently satisfactory. I can not get a good thing.

The fatty acid diester compound (D) and the fatty acid monoester compound (E) referred to in the present invention include capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid and stearic acid. Acid, nonadecanoic acid, arachinic acid, behenic acid, ligglyceric acid, serotinic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, oleic acid, elaidic acid, setleyic acid,
Erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, stearolic acid, 12-hydroxydodecanoic acid, 3-hydroxydecanoic acid, 16-hydroxyhexadecanoic acid, 10-hydroxyhexadecanoic acid, 12 -Hydroxyoctadecanoic acid, 10-hydroxy-8-octadecanoic acid, dl-erythro 9/10 dihydroxyoctadecanoic acid, etc., and alkylene glycols such as ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, styrene oxide, 2-methyltetrahydrofuran, oxepane, etc. The fatty acid diester compound (D) and the fatty acid monoester compound (E). The added mole number of the alkylene glycol is 1 to 70. Among them, the fatty acid is preferably myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, or stearic acid, and the alkylene glycol is (poly) ethylene glycol, a fatty acid diester compound (D) and a fatty acid monoester compound (E). The number of moles of ethylene glycol added is 1 to 10. The more preferable number of moles of ethylene glycol to be added is 1 to 5.

Specific examples of the fatty acid diester compound (D) include (poly) ethylene glycol dimyristate, (poly) ethylene glycol dipentadecylate, (poly) ethylene glycol dipalmitate, and (poly) ) Ethylene glycol diheptadecylate, (poly) ethylene glycol distearate, (poly) ethylene glycol (myristate-palmitate) ester, (poly) ethylene glycol (myristate-stearate) ester,
(Poly) ethylene glycol (palmitic acid-stearic acid) ester, (poly) ethylene glycol (myristic acid-pentadecylic acid) ester, (poly) ethylene glycol (myristic acid-heptadecylic acid) ester, (poly) ethylene glycol (pentadecylic acid) -(Palmitic acid) ester, (poly) ethylene glycol (palmitic acid-heptadecylate) ester, (poly)
Ethylene glycol (heptadecylic acid-stearic acid)
Esters and the like.

Examples of the fatty acid monoester compound (E) include (poly) ethylene glycol monomyristate, (poly) ethylene glycol monopentadecylate, (poly) ethylene glycol monopalmitate, (poly) ethylene Glycol monoheptadecylate, (poly) ethylene glycol monostearate, and the like. Among the fatty acid diester compounds (D), ethylene glycol dimyristate, ethylene glycol dipalmitate, ethylene glycol distearate, ethylene glycol (myristate-palmitate), ethylene glycol (myristate-stearate) ) Esters and ethylene glycol (palmitic acid-stearic acid) esters are preferred, and among fatty acid monoester compounds (E), ethylene glycol monomyristate, ethylene glycol monopalmitate and ethylene glycol monostearate are preferred.

Although the cause of the improvement in the physical properties of the weld after the heat aging test by the addition of the fatty acid diester (D) and the fatty acid monoester (E) is not clear,
Alkaline earth metal salt of difatty acid with improved plasticity (B)
It is presumed that the improvement in the physical properties of the welded portion after the heat aging resistance test is exhibited by the good dispersion and the like. In the method for producing the fatty acid diester compound (D) and the fatty acid monoester compound (E), the raw material fatty acid and alkylene glycol are produced by an esterification reaction using an acid catalyst method or a noncatalytic method. The reaction temperature and the raw material concentration (eg, molar ratio, etc.) at this time are arbitrarily selected depending on the purpose, and can be obtained by purifying and separating the obtained fatty acid ester compound as required.

The obtained fatty acid diester compound (D) and fatty acid monoester compound (E) can be identified by the following method. For example, a fatty acid diester compound and a fatty acid monoester compound are added to a potassium hydroxide-methanol solution and heated to perform hydrolysis. Then, neutralize with hydrochloric acid and add hexane to extract fatty acids. This is methyl-esterified, and the alkyl composition of the fatty acid is analyzed by gas chromatography (GC-FID). Next, with respect to the ester analysis of the fatty acid ester compound, the ester can be dissolved in a solvent or converted into trimethylsilyl (TMS) in some cases, and then analyzed by gas chromatography (GC-FID).

The method of adding the fatty acid diester compound (D) and the fatty acid monoester compound (E) may be a powder or a molten state. In addition, the compound of the essential component alone of the present invention or the compound of the essential component and the polyacetal resin are preferably mixed before melting and kneading for the effect of the present invention. The method may be selected appropriately, and there is no particular limitation. In the present invention, known additives commonly used in polyacetal resins can be used, if desired, as long as the objects of the present application are not hindered. Examples include an antioxidant, a polymer containing a formaldehyde-reactive nitrogen atom, a light stabilizer, a release agent, a pigment, a filler, and the like.
The amount of these additives used varies depending on the type of the additives, but roughly 0.001 to 1 part by weight of each additive based on 100 parts by weight of the polyacetal resin.

As the antioxidant, one or more hindered phenolic antioxidants can be used. Specifically, for example, n-octadecyl-3-
(3 ', 5'-di-t-butyl-4'-hydroxyphenyl) -propionate, n-octadecyl-3-
(3'-methyl-5'-t-butyl-4'-hydroxyphenyl) -propionate, n-tetradecyl-3-
(3 ', 5'-di-t-butyl-4'-hydroxyphenyl) -propionate, 1,6-hexanediol-
Bis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate], 1,4-butanediol-bis- [3- (3,5-di-tert-butyl-4- Hydroxyphenyl) -propionate], triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) -propionate], tetrakis [methylene-3- (3 ′, 5′-di) -T-butyl-4'-hydroxyphenyl) propionate] methane, 3,9-bis [2- {3- (3-t-butyl-4-
[Hydroxy-5-methylphenyl) propionyloxy {-1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro (5,5) undecane, N, N′-bis-3- (3 ′, 5) '-Di-t-butyl-4'-hydroxyphenyl) propionylhexamethylenediamine,
N, N'-tetramethylene-bis-3- (3'-methyl-5'-t-butyl-4'-hydroxyphenol) propionyldiamine, N, N'-bis- [3- (3,5
-Di-t-butyl-4-hydroxyphenol) propionyl] hydrazine, N-salicyloyl-N'-salicylidenehydrazine, 3- (N-salicyloyl) amino-
1,2,4-triazole, N, N′-bis [2- {3
-(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy {ethyl] oxyamide; Preferably, triethylene glycol-bis- [3
-(3-t-butyl-5-methyl-4-hydroxyphenyl) -propionate] and tetrakis [methylene-
3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane.

Examples of the polymer containing a formaldehyde-reactive nitrogen atom include polyamide resins such as nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 12, and the like. Copolymers, for example, nylon 6 / 6-6 / 6-10, nylon 6 / 6-12 and the like can be mentioned. Other examples include acrylamide and its derivatives, and copolymers of acrylamide and its derivatives with other vinyl monomers, for example, obtained by polymerizing acrylamide and its derivatives and other vinyl monomers in the presence of a metal alcoholate. Poly-β-alanine copolymer. Other examples include an amino-substituted triazine compound, an adduct of an amino-substituted triazine compound and formaldehyde, and a polycondensate of an amino-substituted triazine compound and formaldehyde. These polymers containing a formaldehyde-reactive nitrogen atom may be used alone,
More than two types may be combined.

Specific examples of the amino-substituted triazine compound include, for example, guanamine (2,4 diamino-sym
-Triazine), melamine (2,4,6-triamino-sym-triazine), N-butylmelamine, N-phenylmelamine, N, N'diphenylmelamine, N,
N 'diallyl melamine, N, N', N "-triphenyl melamine, benzoguanamine (2,4 diamino-6
-Phenyl-sym-triazine), 2,4-diamino-6-methyl-sym-triazine, 2,4 diamino-6-butyl-sym-triazine, 2,4 diamino-6-benzyloxy-sym-triazine, 2,4 diamino-6-butoxy-sym-triazine, 2,4
N, N ', N "-Tetracyanoethylbenzoguanamine.

Specific examples of the adduct of an amino-substituted triazine compound and formaldehyde include N-methylolmelamine, N, N 'dimethylolmelamine,
N ', N "-trimethylolmelamine. Specific examples of the condensate of an amino-substituted triazine compound and formaldehyde include a melamine-formaldehyde condensate. These amino-substituted triazine compounds The adduct of an amino-substituted triazine compound and formaldehyde and the condensate of an amino-substituted triazine compound and formaldehyde may be used alone or in combination of two or more.

Examples of the light stabilizer include at least one of a benzotriazole-based and oxalic anilide-based ultraviolet absorber and a hindered amine-based light stabilizer. Examples of the benzotriazole-based ultraviolet absorber include 2- (2 ′
-Hydroxy-5'-methyl-phenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t
-Butyl-phenyl) benzotriazole, 2- (2 ′
-Hydroxy-3 ', 5'-di-isoamyl-phenyl) benzotriazole, 2- [2'-hydroxy-
3 ', 5'-bis- (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole and the like. Examples of the oxalic acid alinide UV absorber include 2-ethoxy-2'-ethyloxalic acid bisanilide and 2-ethoxy-5-t-butyl-
2'-ethyloxalic acid bisanilide, 2-
Ethoxy-3'-dodecyloxalic acid bisanilide and the like. These ultraviolet absorbers may be used alone or in combination of two or more.

Examples of hindered amine light stabilizers include 4-acetoxy-2,2,6,6-tetramethylpiperidine and 4-stearoyloxy-2,2,6,
6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (phenylacetoxy) -2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2 , 6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6
-Tetramethylpiperidine, 4-stearyloxy-
2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy- 2,2,6,6-tetramethylpiperidine, 4- (ethylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4-
(Cyclohexylcarbamoyloxy) -2,2,6
6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) -carbonate, bis (2 2,6,6-tetramethyl-4-piperidyl) -oxalate, bis (2
2,6,6-tetramethyl-4-piperidyl) -malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) -sebacate, bis (2,2,6,6-tetramethyl-4) -Piperidyl) -adipate, bis (2,
2,6,6-tetramethyl-4-piperidyl) -terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -ethane, α, α′-bis (2 2,6,6-tetramethyl-4-piperidyloxy) -p-xylene, bis (2,2,6,6-tetramethyl-4-piperidyltolylen-2,4-dicarbamate, bis (2,2 , 6,6-tetramethyl-4-piperidyl) -hexamethylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,5-tri Carboxylate,
Tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,4-tricarboxylate,
1- [2- {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy} butyl] -4-
[3- (3,5-Di-t-butyl-4-hydroxyphenyl) propionyloxy] 2,2,6,6-tetramethylpiperidine, 1,2,3,4-butanetetracarboxylic acid and 1,2 , 2,6,6-pentamethyl-4-piperidinol and β, β, β ', β'-tetramethyl-3,9
-[2,4,8,10-tetraoxaspiro (5,5)
Undecane] condensate with diethanol.
The hindered amine light stabilizers may be used alone or in combination of two or more. Moreover, you may combine with the above-mentioned benzotriazole type ultraviolet absorber or oxalic anilide type ultraviolet absorber. Examples of the release agent include at least one selected from polyalkylene glycols, aliphatic compounds having an amide group, and polyolefin polymers.

As the polyalkylene glycol, a polyalkylene glycol represented by the following general formula (III) can be used.

Embedded image (Wherein, R ⁶ is selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted alkyl group, and a substituted allyl group, and each R ⁶ may be the same or different. X is 2 ~
Integer of 6, Y represents 1000 to 20000. )

This polyalkylene glycol can be obtained by ring-opening polymerization of an alkylene oxide. Specific examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, styrene oxide, oxetane, 3, 3
-Bis (chloromethyl) oxetane, tetrahydrofuran, 2-methyltetrahydrofuran and oxepane. These polyalkylene glycols may be used alone or in combination of two or more.

As the aliphatic compound having an amide group,
An aliphatic compound represented by the following general formula (IV).

Embedded image (Wherein, R ⁷ and R ⁹ are alkyl groups having 9 to 35 carbon atoms, and may be the same or different. R ⁸
Represents an alkylene group having 1 to 6 carbon atoms. )

Specific examples include ethylene bispalmitic acid amide, ethylene bis stearic acid amide, ethylene bis lauric acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, and the like, and ethylene (monopalmitic acid / monostearic acid amide). Acid) amide, ethylene (monostearic acid / monoheptadecylic acid) amide, and the like. These aliphatic compounds having an amide group may be used alone or in combination of two or more.

The polyolefin polymer is a polyolefin polymer represented by the following general formula (V).

Embedded image (R ¹⁰ is selected from hydrogen, an alkyl group having 1 to 6 carbon atoms and a substituted allyl group, and may be the same or different, and Z represents 10 to 100,000.) As a specific example, Examples include an ethylene polymer, a propylene polymer, a butylene polymer, and an ethylene / propylene copolymer.

The pigments include inorganic pigments, organic pigments,
Examples include metallic pigments and fluorescent pigments. Specific examples of the inorganic pigments include rutile-type or anatase-type titanium oxide, iron oxide, ultramarine, carbon black, titanium yellow, and the like.As organic pigments, azo pigments, phthalocyanine pigments, anthraquinone pigments, perinones Pigments, perylene pigments, quinacridone pigments, isoindoline pigments, thioindigo pigments, dioxazine pigments, isobiolanthrone pigments, indanthrone pigments and the like. Examples of the filler include various reinforcing agents such as glass fiber, glass beads, glass balloon, wollastonite, carbon fiber, talc, mica, and titanium whisker, and a nucleating agent represented by boron nitride. The addition form of the additive containing the compound of the essential component of the present invention may be a powder or a molten state. In addition, it is preferable for the effect of the present invention that the additive alone or the additive and the polyacetal resin are pre-mixed before melting and kneading, and the pre-mixing method is appropriately selected by a known method. Well, there is no particular limitation.

The method for producing the polyacetal resin composition of the present invention is not particularly limited. In general,
Using an extruder, the polyacetal resin and the compound of the essential components defined herein, and further, if desired, by melting and kneading the optional additives, to produce the polyacetal resin composition of the present invention. it can. The extruder at this time may be single-screw or twin-screw. Further, an additive may be added during the polymerization of the polyacetal resin. The temperature of the extruder can be appropriately selected usually in the range of 170 ° C to 240 ° C, and is not particularly limited. The method for molding the resin composition of the present invention is not particularly limited, and may be any of known molding methods such as extrusion molding, injection molding, compression molding, vacuum molding, blow molding, foam molding, insert molding, and outsert molding. , Can be molded. The polyacetal resin composition of the present invention can be suitably used for mechanical parts of electric equipment and electronic equipment, automobile parts, and other mechanical parts.

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to synthesis examples, adjustment examples, measurement methods, examples and comparative examples. (1) Manufacture of polyacetal resin (A) 1: Manufacture of polyacetal resin (a-1) A 5-liter capacity kneader having two jacketed stirring blades through which a heating medium can pass was adjusted to 80 ° C. 1
3kg of trioxane containing 5ppm water and 100p
pm tetrakis [methylene-3- (3 ′, 5′-di-
1,3-Dioxolane to which [t-butyl-4-hydroxyphenyl) propionate] methane is added, 4.0 mol% based on 1 mol of trioxane, and 0.7 × 10 ⁻³ mol of methylal as a molecular weight modifier are added and mixed. did. To this mixture, as a polymerization catalyst, boron trifluoride dibutyl ether was added in an amount of 0.15 to 1 mol of trioxane.
× 10 ^-4 mol was added to carry out polymerization. After the start of the reaction, 30
After a lapse of minutes, a heating medium at 30 ° C. was passed through the jacket, 2 liters of an aqueous solution containing 1% triethylamine was added, and the catalyst was deactivated in 1 hour to stop the reaction. Then, after taking out the contents of the kneader and filtering,
The filter cake was dried at 100 ° C. to obtain 2.7 kg of a polyacetal resin. A twin screw extruder (L / D ratio: 32) having one 30 mm vent port for the obtained polyacetal resin.
Supplied. The extruder temperature was 200 ° C., and the amount of water to be injected into the reaction zone of the extruder and the addition amount of triethylamine used as the basic substance were 0.2% by weight based on the resin.
And stabilization and deaeration of the polyacetal resin under the condition of 0.1% by weight and a vent vacuum of 200 mmHg,
The terminal-stabilized polyacetal resin (a-1) was obtained in the form of pellets. Obtained polyacetal resin (a-1)
Is 1100 ppm in the measurement method described below, and the melt index value is 10 g /
10 minutes.

2: Production of polyacetal resin (a-2) Substantially the same as the production of polyacetal resin (a-1), except that the degree of vacuum of the extruder was 700 mmHg when the polyacetal resin was end-stabilized. Operation, and
An end-stabilized polyacetal resin (a-2) was obtained.
The obtained polyacetal resin (a-2) had a formaldehyde gas generation amount of 260 ppm and a melt index value of 10 g / 10 min.

(2) Method for producing alkaline earth metal salt of difatty acid (B) 1: Production method for alkaline earth metal salt of difatty acid (b1) 100 g of stearic acid and 100 g of palmitic acid are added to 0.6.
Add to 1 liter of water and heat to 80 ° C with stirring.
After dissolving the seed fatty acids and diffusing them into water, 4 g of calcium-substituted A-type zeolite is added, and the mixture is stirred for 30 minutes, and 0.7 liter of water is added to adjust the temperature to 50 ° C. Next, 0.
39 g of calcium hydroxide was added to 7 liters of water while stirring to disperse the mixture, and this calcium hydroxide dispersion was gradually added to the above-mentioned fatty acid solution to adjust the temperature to 65 ° C.
Stirring was continued for 0 minutes, the alkaline earth metal salt of difatty acid obtained as a precipitate was separated by filtration, washed with 0.4 liter of hot water at 80 ° C. 50 times (total water volume = 20 liters), and then dried. Then, a difatty acid alkaline earth metal salt (b1) in which no fatty acid was detected by the following detection method was produced.

The fatty acids in the obtained alkaline earth metal salt of difatty acid were analyzed as follows. After mixing 50 g of the dried difatty acid alkaline earth metal salt and 500 g of water, 8
After heating at 0 ° C. for 30 minutes, the alkaline earth metal salt of difatty acid and water were separated by filtration, and the evaporator (400 mmHg: 8) was used.
(0 ° C.) to concentrate the filtrate to 1 g. The liquid is subjected to gas chromatography mass spectrometry (GC-MS: HP5890 + HP5971A, manufactured by Hewlett-Packard Company).
Was used to confirm whether fatty acids could be detected. The presence of stearic acid and palmitic acid was not confirmed. In addition, the detection limit value of the fatty acid in GC-MS used for this detection is 1 ppm in the injection amount of 1 μl under the fixed condition. From these results, it was found that the content of stearic acid and palmitic acid contained in the di-fatty acid alkaline earth metal salt was 40 pp
It turns out that it is t or less.

2: alkaline earth metal salt of difatty acid (b2)
The production method of diacid fatty acid alkaline earth metal salt (b2) in which no fatty acid was detected by the above-mentioned detection method was produced according to the production method of difatty acid alkaline earth metal salt (b1) using 200 g of palmitic acid. 3: Production method of alkaline earth metal salt of difatty acid (b3) According to the production method of alkaline earth metal salt of difatty acid (b1) using 200 g of stearic acid, the alkaline earth metal difatty acid in which no fatty acid is detected by the above detection method is used. A salt (b3) was produced.

4: alkaline earth metal salt of difatty acid (b4)
Using 99.9 g of palmitic acid, 0.2 g of heptadecylic acid, and 99.9 g of stearic acid, according to the method for producing a difatty acid alkaline earth metal salt (b1), a difatty acid alkaline earth in which no fatty acid is detected by the above detection method is used. A metal salt (b4) was produced. The unreacted metal compound in the resulting difatty acid alkaline earth metal salt (b4) is obtained by adding 10 g of difatty acid alkaline earth metal salt (b4) to 100 ml of water, and then using an ultrasonic cleaner (Masuda Rika Co .; W: -2) for 10 minutes, and the calcium metal component extracted in the filtrate is quantified by an electric conductivity detector (431, manufactured by Waters), and the obtained quantitative value is converted into the raw material calcium hydroxide. It was 220 ppm when determined.

5: Alkaline earth metal salt of difatty acid (b5)
Using 99 g of palmitic acid, 2 g of heptadecylic acid and 99 g of stearic acid, a difatty acid alkaline earth metal salt (b
According to the production method 1), a difatty acid alkaline earth metal salt (b5) in which no fatty acid was detected by the above detection method was produced. 6: Production method of difatty acid alkaline earth metal salt (b6) Using 5 g of palmitic acid, 10 g of heptadecylic acid, and 5 g of stearic acid, difatty acid alkaline earth metal salt (b1)
In the same method, except that the amounts of water and calcium hydroxide used were each reduced to 1/10, an alkaline earth metal difatty acid salt (b6) in which no fatty acid was detected by the following detection method was produced. 5 g of the obtained difatty acid alkaline earth metal salt (b6) and 50 g of water were mixed,
After heating for 0 minutes, the alkaline earth metal salt of difatty acid and water are separated by filtration, and the filtrate is concentrated to 0.1 g using an evaporator. The solution was subjected to gas chromatography mass spectrometry to confirm the detection of fatty acids in the same manner as described above.

7: alkaline earth metal salt of difatty acid (b7)
Using 100 g of lauric acid and 100 g of myristic acid,
According to the method for producing a difatty acid alkaline earth metal salt (b1), a difatty acid alkaline earth metal salt (b7) from which no fatty acid was detected by the above detection method was produced. 8: Method for producing alkaline earth metal salt of difatty acid (b8) Diacid in which no fatty acid is detected by the above-mentioned detection method according to the method for producing alkaline earth metal salt of difatty acid using 100 g of arachidic acid and 100 g of behenic acid. An alkaline earth metal salt (b8) was produced.

9: alkaline earth metal salt of difatty acid (b9)
The metal component is changed from calcium hydroxide to magnesium hydroxide, and according to the method for producing a difatty acid alkaline earth metal salt (b1), a difatty acid alkaline earth metal salt (b9) in which no fatty acid is detected by the above detection method is used. ) Manufactured. 10: Production Method of Alkaline Earth Metal Salt of Difatty Acid (b10) An aqueous solution of calcium hydroxide was sprayed on the alkaline earth metal salt of difatty acid (b4), and dried. Calculated value of 780p
pm to produce a difatty acid alkaline earth metal salt (b10).

The additives used in other examples and comparative examples are as follows. (3) fatty acid (C) c1: lauric acid c2: myristic acid c3: palmitic acid c4: heptadecylic acid c5: stearic acid c6: arachiic acid c7: behenic acid

(4) Fatty acid diester compound (D) d1: Ethylene glycol dipalmitate (the number of moles of ethylene glycol added: 1) d2: Ethylene glycol distearate (the number of moles of ethylene glycol added: 1) d3: Ethylene Glycol (myristic acid-palmitic acid) ester (addition mole number of ethylene glycol: 1) d4: ethylene glycol (palmitic acid-stearic acid) ester (addition mole number of ethylene glycol: 1) d5: ethylene glycol distearate ester (ethylene Number of moles of added glycol: 7) d6: ethylene glycol distearate (number of moles of added ethylene glycol: 70)

(5) Fatty acid monoester compound (E) e1: Ethylene glycol monopalmitate (the number of moles of ethylene glycol added: 1) e2: Ethylene glycol monostearate (the number of moles of ethylene glycol added: 1) e3 : Ethylene glycol monostearate (number of moles of ethylene glycol added: 7) e4: ethylene glycol monostearate (number of moles of added ethylene glycol: 70) (6) Hindered phenolic antioxidant f1: triethylene glycol -Bis- [3- (3-t
-Butyl-5-methyl-4-hydroxyphenyl) propionate] (7) a compound containing a formaldehyde-reactive nitrogen atom,
Polymer g1: Nylon 6-6 g2: Melamine

(8) ESCR measurement method Using an injection molding machine (Nestal injection molding machine manufactured by Sumitomo Heavy Industries, Ltd.) having an injection capacity of 5 ounces, the cylinder temperature was set to 200 ° C. and the mold temperature was set to 80 ° C. Then, a molded piece (length = 127 mm, width = 13 mm, thickness = 3 mm) was molded under the conditions of an injection time: 20 seconds and a cooling time: 10 seconds, and the obtained molded piece was cured to a length of 111 mm. It was attached to the tool while bending it, and after immersion in a 2N hydrochloric acid aqueous solution at 23 ° C., the time required for cracking to break was measured. The number of measurements was 100 for each of Examples 1 to 26 and Comparative Examples 1 to 9, and 30 for each of Examples 30 to 55 and Comparative Examples 13 to 20. The average value (seconds) of each sample and the number of samples in which cracks occurred in a time shorter than 80% of the average value (in the table, indicated by "average -20%").

(9) Evaluation of Physical Properties of Weld Portion {1} Molding of Dumbbell-Type Specimen with Weld Portion An injection molding machine (Nestal injection molding machine manufactured by Sumitomo Heavy Industries, Ltd.) having an injection capacity of 5 oz was used. And cylinder temperature: 200 ° C, mold temperature: 70 ° C, injection time: 15
Seconds, cooling time: 25 seconds, specimen size: 13 mm x 1
A molded piece having a weld line at the center of the molded product was obtained under the conditions of 80 mm × 3 mm, gate: 2 points (dub gate). {2} Molding of Dumbbell-Type Specimen without Weld Part Gate was obtained according to the above molding conditions except that the point was changed to one point (dub gate). {3} Test method for heat aging resistance The test piece was suspended in a gear oven set at 150 ° C and heated for 240 hours. Thereafter, the test piece was taken out of the gear oven and left in a constant temperature room maintained at 23 ° C. and a humidity of 50% for 2 days. The tensile strength and elongation (between 114 mm chucks) of the test piece left in the constant temperature chamber were measured under the following conditions. The measurement of the physical properties before the aging test was performed by placing the test piece in a thermostatic chamber maintained at 23 ° C. and 50% humidity.
Those left for days were used. Tensile testing machine: Autograph A manufactured by Shimadzu Corporation
G-1000B Tensile speed: 5 mm / min

(10) Appearance Observation of Molded Article Whether silver (a mark such as a scratch caused by decomposition of polyacetal resin or the like) is generated on the molded piece molded for the above ESCR measurement, and there is no discoloration. Was visually observed. (11) Formaldehyde gas generation amount 3 g of polyacetal resin was placed in an aluminum container, and heated and melted at 230 ° C. for 50 minutes under a nitrogen stream (6 liters / hour), and the formaldehyde generated at that time was 1 m
ol / liter sodium sulfite aqueous solution,
Titrate with 0.01 N sulfuric acid to determine the amount of formaldehyde gas generated, and determine the weight per weight of the polyacetal resin, p
pm.

[0070]

Examples 1 to 24 and 26, Comparative Examples 1 to 9 The compositions shown in Tables 1, 2 and 3 were prepared by using a vent having an inner diameter of 30 mm.
Using a screw extruder (L / D: 32), cylinder temperature:
200 ° C., screw rotation speed: 100 rpm, discharge amount:
The mixture was melt-kneaded at 5 kg / hr and a degree of vent vacuum of 700 mmHg to form pellets. Using the obtained pellets, ESCR measurement, evaluation of weld properties, and observation of the appearance of a molded product were performed by the above-described evaluation methods. The obtained results are shown in Tables 5 and 6. In addition, what is described as "measurement impossible" in the result after the weld part aging, at the end of the aging test,
The weld is already broken or the tensile strength is 50k
This indicates that the fracture occurred when the elongation was less than 1 g / cm ² or less than 1%. In addition, for samples using both fatty acid alkaline earth metal salts and fatty acids, to mix in advance,
The fatty acid is dissolved in water at 80 ° C., and the diacid fatty acid alkaline earth metal salt is mixed with the fatty acid solution. After that, it was dried and used after being crushed in an agate mortar for 5 minutes. In addition, when the difatty acid alkaline earth metal salt or the fatty acid was used alone, the pulverizing operation was similarly performed in an agate mortar for 5 minutes.

As a result, as compared with Example 9 in which two kinds of fatty acids, which are the raw materials of the di-fatty acid alkaline earth metal salt, were mixed to prepare the di-fatty acid alkaline earth metal salt, the di-fatty acid obtained by adjusting the fatty acid alone was used. In Comparative Example 6 in which one kind of the fatty acid alkaline earth metal salt was used in the same addition amount, and in Comparative Examples 8 and 9 in which the two kinds were mixed, it was confirmed that the results were inferior to Example 9. Was. Further, the fatty acid used as a raw material of the difatty acid alkaline earth metal salt (B) is a difatty acid alkaline earth metal salt (B) produced by using a combination of an odd-numbered fatty acid and an even-numbered fatty acid, and a fatty acid. Examples 21 to 23 in which (C) used the same fatty acid as the raw material used in the difatty acid alkaline earth metal salt (B), and also used a fatty acid having an odd number of carbon atoms and a fatty acid having an even number of carbon atoms in the ESCR Has been remarkably improved, and the variation has been surprisingly improved.

[0072]

Example 25 In the method relating to pelletization performed in Example 1 and the like, a pulverizing operation was performed separately without previously mixing the difatty acid alkaline earth metal salt (B) and the fatty acid (C).
Using the pellets obtained by dry blending with the polyacetal resin, the ESCR measurement, the evaluation of the physical properties of the weld, and the appearance observation of the molded product were carried out by the above-mentioned evaluation methods. Table 5 shows the obtained results.

[0073]

Examples 27 to 29 Comparative Examples 10 to 12 An injection molding machine (PLA manufactured by Toyo Machine Metal Co., Ltd.) having an injection capacity of 1 oz.
STAR injection molding machine), cylinder temperature: 20
0 ° C, mold temperature: set to 80 ° C, 3 on the φ17 circumference
A gear having a point web gate (gate size: φ1.7), a module 1, 30 teeth, a pressure angle of 20 degrees, a thickness of 5 mm, a pitch circle diameter of 30 mm, a tooth tip circle diameter of 32 mm, and a hub inner diameter of 6 mm was formed. The gear 1 was fixed to the jig shown in FIG. 1 so as not to rotate, and was mounted at a position where the teeth of the gear 1 and the gear 2 meshed with each other so that the gear 2 could rotate around the shaft. With 100 g of weight applied to the outer periphery of the gear 2,
After immersion in a 2N aqueous hydrochloric acid solution at 23 ° C., the time required for the meshed portion of the tooth tip to crack and break was measured.
Gears 1 and 2 were measured using a resin molded product having the same composition. The number of measurements was 10 times, and the average value (second) of each sample and the time shorter than 80% of the average value (in the table). "Average -20%")) and the number of samples in which cracks occurred. Further, the gears were visually observed for streaks and for discoloration. The compositions and the results obtained are shown in Tables 4 and 7. As the physical property evaluation of the weld portion, the outer diameter is 6.24 m.
m and 6.36 mm stainless steel shaft (SUS-31
6) was press-fitted into the hub portion of the above-mentioned gear molded piece, and the number of samples was set to five. Further, as in Example 1 and the like, for a sample in which a difatty acid alkaline earth metal salt and a fatty acid are used in combination, the fatty acid is dissolved in water at 80 ° C. in order to mix them in advance. And the fatty acid solution. After that, it was dried and used after being crushed in an agate mortar for 5 minutes. Similarly, when using diacid fatty acid alkaline earth metal salts or fatty acids alone, 5
The grinding operation was performed for minutes.

[0074]

Examples 30 to 55, Comparative Examples 13 to 20 Polyacetal resin (A), alkaline earth metal salt of difatty acid (B), fatty acid (C), fatty acid diester (D), fatty acid monoester (E) and optional Was added to a Henschel mixer, uniformly mixed at a rotation speed of 860 rpm for 2 minutes, and discharged. The obtained mixture was melted and kneaded at a temperature of 200 ° C. using a twin-screw extruder having an inner diameter of 30 mm to form pellets.
Using the pellets obtained, ES
CR measurement, evaluation of weld physical properties, and observation of the appearance of the molded product were performed. The composition tables are shown in Tables 8, 9 and 10, and the obtained results are shown in Tables 11 and 12. When the results after the aging of the weld portion are described as "measurable", the weld portion has already broken at the end of the aging test, the tensile strength is less than 50 kg / cm ^2, or the elongation is less than 1%. Indicates that it was broken. Examples 3 and 33, Examples 4 and 30 and Examples 5 and 34 are comparisons of the presence or absence of the fatty acid diester (D) and the fatty acid monoester (E). It was confirmed that the composition to which was added was further improved in the retention of weld physical properties after the heat aging resistance test as compared to the composition without the additive.

[0075]

[Table 1]

[0076]

[Table 2]

[0077]

[Table 3]

[0078]

[Table 4]

[0079]

[Table 5]

[0080]

[Table 6]

[0081]

[Table 7]

[0082]

[Table 8]

[0083]

[Table 9]

[0084]

[Table 10]

[0085]

[Table 11]

[0086]

[Table 12]

[0087]

The resin composition of the present invention improves the ESCR and weld properties by adding a specific difatty acid alkaline earth metal salt and a specific fatty acid to a polyacetal resin. The heat aging resistance of the weld portion is improved by adding specific fatty acid esters. Therefore, the polyacetal resin composition of the present invention can be used for a wide range of uses such as automobile parts, parts for electric / electronic devices, industrial parts such as door cars, and especially mechanical mechanism parts (eg, gears) subjected to stress, under high temperature. It is suitable for automobile mechanism parts that are exposed to

[Brief description of the drawings]

FIG. 1 shows Examples 27 to 29 of the present invention and Comparative Examples 10 to 12.
FIG. 4 is an explanatory diagram of a method for measuring an ESCR in FIG.

FIG. 2 is an analysis chart for confirming an odd-numbered and even-numbered fatty acid by GC-MS.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-39351 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 59/00-59/04

Claims (11)

(57) [Claims] 1. (B) 0.001 to 1.0 part by weight of a difatty acid alkaline earth metal salt produced by mixing two or more kinds of fatty acids with respect to 100 parts by weight of a polyacetal resin (A). (C) A polyacetal resin composition containing 1 × 10 ^-6 to 1 × 10 ^-1 parts by weight of a fatty acid. 2. The weight ratio of fatty acid (C) to difatty acid alkaline earth metal salt (B) is C / B = 0.1 / 100-10.
The polyacetal resin composition according to claim 1, which is in the range of / 100. 3. The polyacetal resin composition according to claim 1, wherein the fatty acid (C) is a combination of two or more fatty acids. Wherein the fatty acid (C) is, and one or more fatty acids consisting of odd number of carbon atoms, the fatty acid consisting of an even number of carbon atoms 1
And the total amount of fatty acids having an odd carbon number (C1) and the total amount of fatty acids having an even carbon number (C1).
2) C1 / C2 = 0.1 / 99.9-9
The polyacetal resin composition according to any one of claims 1 to 3, which is in a range of 9.9 / 0.1. 5. The method according to claim 5, wherein the fatty acid (C) is at least one of the fatty acids used in the production of the difatty acid alkaline earth metal salt (B).
The polyacetal resin composition according to any one of claims 1 to 4, which is a seed. 6. The fatty acid used in the production of the difatty acid alkaline earth metal salt (B) is a combination of at least one fatty acid having an odd carbon number and at least one fatty acid having an even carbon number. The weight ratio of the total amount of fatty acids having even carbon numbers (B1) to the total amount of fatty acids having odd carbon numbers (B2) is B1 / B2 = 0.1 / 99.9 to 99.9 / 0.9. The polyacetal resin composition according to any one of claims 1 to 5, which is in the range of 1. 7. The diacid fatty acid alkaline earth metal salt (B) has a metal component of calcium, and the fatty acid used for producing the difatty acid alkaline earth metal salt (B) is lauric acid,
The polyacetal resin composition according to any one of claims 1 to 6, wherein the polyacetal resin is at least two selected from tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, and behenic acid. object. 8. The polyacetal resin composition according to claim 1, wherein (D) a fatty acid diester compound represented by the following general formula (I) and (E) a fatty acid monoester compound represented by the following general formula (II): A polyacetal resin composition added. General formula (I) R ¹ —COO (R ³ O) _n —COR ² (R ¹ and R ² are an alkyl group having 9 to 35 carbon atoms, or an alkenyl group, or an alkyl group substituted with one hydroxyl group. Or an alkenyl group, R ¹ and R ² may be the same or different, and R ³ O has 2 to 6 carbon atoms.
Represents an alkylene glycol unit. Also, n is 1
Represents an integer of ~ 70. ) General formula ^{(II) R 4 -COO (R} 5 O) m -H (R 4 is the alkyl group substituted alkyl group of 9-35 carbon atoms, or an alkenyl group, or one hydroxyl group, or alkenyl R ⁵ O represents an alkylene glycol unit having 2 to 6 carbon atoms, and m represents 1 to
Represents an integer of 70. ) 9. The total addition amount of the fatty acid diester compound (D) and the fatty acid monoester compound (E) is as follows:
0.005 to 100 parts by weight of the polyacetal resin
And the weight ratio of the fatty acid diester compound (D) to the fatty acid monoester compound (E) is (D) / (E) = 99.9 / 0.1 to 0.1 /. 99.9
The polyacetal resin composition according to claim 8, wherein 10. The polyacetal resin composition according to claim 1, wherein said polyacetal resin generates 500 ppm or less of formaldehyde gas when heated at 230 ° C. for 50 minutes in a nitrogen atmosphere. 11. A molded gear formed by using the polyacetal resin composition according to claim 1. Description: