JPH0733953A - Polyacetal resin composition - Google Patents

Abstract

PURPOSE:To provide a new polyacetal resin compsn. which is very excellent in heat resistance and free from problems with discoloration or photosensitization caused by an antioxidant. CONSTITUTION:A polyacetal resin compsn. is prepd. by homogeneously melt mixing 100 pts.wt. polyacetal resin with 0.01-10.0 pts.wt. acrylate deriv., 0.01-5.0 pts.wt. melamine, and if necessary at least one compd. selected from the group consisting of 0.01-1.0 pt.wt. alkali or alkaline earth metal compd. and 0.01-5.0 pts.wt. hydrazide deriv.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel polyacetal resin composition having improved thermal stability. More specifically, the present invention relates to a polyacetal resin containing an acrylate derivative, melamine, or an alkali metal. , A new polyacetal with improved thermal stability, which is obtained by adding and blending one kind or two or more kinds selected from the group consisting of alkaline earth metal compounds and hydrazide derivatives, and uniformly melting and kneading the mixture. The present invention relates to a resin composition.

[0002]

2. Description of the Related Art Polyacetal resins are excellent in physical properties such as friction and wear resistance, fatigue resistance, electrical properties, and chemical properties such as chemical resistance and water resistance. Mainly used in the field of metal substitution,
For example, it is used as parts in the electric / electronic field, the construction field, the automobile industry, the sundries field, and the like.

Polyacetal resins have poor thermal stability due to their molecular structure as compared with other polymers. Under the conditions of thermal oxidation in the molding process, thermal oxidative decomposition such as depolymerization from the polymer molecular end and main chain cleavage occurs, but the formalin generated by thermal oxidative decomposition is further oxidized to formic acid, resulting in thermal oxidation of the polymer. Promotes decomposition. Therefore, in order to improve the thermal stability of the polyacetal resin, conventionally, by polymer chain scission, and in order to trap radicals generated by decomposition of hydroperoxide in the oxidized polymer molecule, an antioxidant, particularly,
Add an antioxidant of hindered phenols.

To capture formalin generated by polymer decomposition, formalin receptors such as melamine, urea and various polyamides are added. Further, it has been proposed to add a formic acid acceptor such as an alkali or alkaline earth metal compound in order to capture formic acid generated by the oxidation of forimarin. For example, a method of blocking formalin reaction of a polymer cleaved by thermal oxidation and capturing formalin and formic acid at the same time, that is, an antioxidant and formalin receptor, or an antioxidant and formic acid receptor in combination The method is disclosed in JP-B-40-21148, JP-A-59-191753, and JP-B-60-5674.
No. 8 publication and the like. Further, a method of using an antioxidant, a formalin receptor and a formic acid receptor in combination is disclosed in JP-B-56-10939, JP-A-57-102943, JP-B-60-84348 and JP-B-62-4422. Have been described.

In any of the stabilizer formulations of resin compositions proposed in the above-mentioned patents, antioxidants, particularly hindered phenols, are used as radicals generated by polymer molecule cleavage or hydro-forms in the polymer. Captures radicals generated by decomposition of peroxides,
It is said to be particularly effective and indispensable for improving the thermal stability of the polyacetal resin because it can efficiently prevent the radical chain reaction.

[0006]

However, the hindered phenolic antioxidants trap various radicals and prevent the progress of the thermal oxidation reaction of the polymer, and at the same time, produce various quinone compounds from themselves. These quinone-based compounds often cause polyacetal coloration, and when they are added in a large amount, they often decompose to become polyacetal decomposition accelerators. Nevertheless, since many of these quinone compounds have absorption in the ultraviolet region and have a photosensitizing effect, their weather resistance (light) rapidly deteriorates when the polyacetal sample is irradiated with light. . Further, even when the antioxidant and the light stabilizer are used in combination, the antioxidant and the light stabilizer cause a chemical reaction and consume the light stabilizer, which reduces the weather resistance (light) of the polyacetal resin. Often. These problems remain as important technical issues.

In order to solve the above-mentioned problems, the inventors of the present invention have made earnest studies on a polyacetal resin composition, and as a result, have found that polyacetal resin contains an acrylate derivative, melamine, or an alkali metal or alkaline earth metal. Excellent friction and wear resistance of the original polyacetal resin by adding and blending one kind or two or more kinds selected from metal compounds and hydrazide derivatives, and uniformly kneading. And fatigue resistance,
And, we obtained the knowledge that a new polyacetal resin composition with extremely excellent heat resistance can be obtained without impairing chemical resistance and electrical properties, and further conducted technical improvement and confirmation experiments of reproducibility. Then, the present invention was completed.

[0008]

The present invention provides a polyacetal resin, an acrylate derivative, melamine, or an alkali metal or alkaline earth metal compound,
The present invention relates to a novel polyacetal resin composition having improved heat resistance, which is obtained by adding and blending one kind or two or more kinds selected from hydrazide derivatives and uniformly kneading them. More specifically, in the present invention, the acrylate derivative (B) is 0.01 to 10.0 parts by weight and the melamine (C) is 0.01 to 5.0 parts by weight with respect to 100 parts by weight of the polyacetal resin (A). And a novel polyacetal resin composition having improved heat resistance. Alternatively, 0.01 to 1.0 part by weight of an alkali metal or alkaline earth metal compound (D), and a hydrazide derivative (E) 0 with respect to the components (A), (B), and (C) described above. 0.01 to 5.0 parts by weight, one kind selected from two or more kinds is added and blended,
The present invention relates to a novel polyacetal resin composition having an improved heat resistance obtained by uniformly melt-kneading.

In the present invention, the polyacetal resin (A) means a polyacetal (polyoxymethylene) and a polyacetal copolymer that are already commercially available. More specifically, for example, formaldehyde or its trimer (trioxane),
And an oxymethylene homopolymer substantially composed of an oxymethylene unit structure produced from the tetramer (tetraoxane) as a raw material, and / or formaldehyde, or a trimer thereof (trioxane), and its quaternary amount Body (tetraoxane) and ethylene oxide, epichlorohydrin, 1,3-dioxolane, 1,
Oxygen containing 0.1 to 20% by weight of an oxyalkylene unit structure produced from a cyclic ether having 2 to 8 carbon atoms such as 3,5-trioxepane, glycol formal, diglycol formal, and diglycol formal. Methylene copolymer, and / or oxymethylene homopolymer, or block structure other than oxymethylene unit structure having oxymethylene copolymer as a main structure, or oxymethylene block copolymer having a terminal structure, or oxymethylene graft polymer, or It means a known oxymethylene crosslinked polymer having a crosslinked structure.

The acrylate derivative (B) added / blended in the present invention means the following general formula

[0011]

[Chemical 4]

[R ₁ is hydrogen or a methyl group, and n is an integer of 1 or more. However, when n = 1, R ₂ is an n-valent unsaturated hydrocarbon, in which a carbon double bond, or
A triple bond or the like must contain at least one or more. When n ≧ 2, R ₂ is a residue of an n-hydric alcohol]. More specifically, for example, an unsaturated alkyl acrylate compound having an acrylate-derived group composed of various unsaturated alkyls,
Alternatively, ether acrylate compounds having an acrylate-derived group, such as various alkyl glycols, polyalkyl glycols, trimethylolethane, trimethylolpropane, pentaerythritol, etc., can be mentioned. The acrylate derivative in the present invention may be in any physical state such as liquid, powder, flakes, lumps, and pellets, and is included in the present invention.

In the present invention, the alkali metal or alkaline earth metal compound (D) means an alkali metal or alkaline earth metal hydroxide, inorganic acid salt,
It means carboxylate, metal salt of alcohol, and the like. More specifically, examples of the hydroxide include sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide and the like. As the inorganic acid salt, for example, carbonic acid, phosphoric acid, silicic acid, sodium borate, potassium, magnesium, calcium,
Examples thereof include barium and other metal salts.
As the carboxylic acid salt, monovalent, divalent, or polyvalent carboxylic acid salts, for example, acetic acid, butyric acid, montanic acid, citric acid, adipic acid, sodium stearate and the like, potassium, magnesium, calcium, barium, and,
Other metal salts and the like can be mentioned. Further, as the metal salt of alcohol, for example, methanol, ethanol, 1-
Sodium, potassium, magnesium, calcium such as dodecanol, 1-tridecanol, 1-pentadecanol, stearyl alcohol, 1-eicosanol,
Barium and other metal salts may be mentioned.

The hydrazide derivative (E) to be added / blended in the present invention means the following general formula

[0015]

[Chemical 5]

[0016]

[Chemical 6]

[Wherein R ₁ and R ₂ mean a saturated or unsaturated alkyl group, an aryl-derived group, etc., and R ₃ means a divalent saturated or unsaturated alkyl group, an aryl-derived group, etc.] It means that it is shown by. More specifically, for example, isophthalic acid bis [2-phenoxypropionylhydrazide], N, N′-bis [3-
(3,5-di-t-butyl-4-fodoxyphenyl)
Propionyl] hydrazine, decanedicarboxylic acid disalicyloyl hydrazide and the like can be mentioned.

In the present invention, the reason why the heat resistance of the polyacetal resin is improved by adding the acrylate derivative and the melamine to the polyacetal resin can be interpreted as follows based on the experimental results. it can. By thermal oxidation, if one site in one polyacetal molecule is oxidatively cleaved, two polymer radicals are generated, and since the formalin reaction occurs one after another from the radical end of this polymer radical,
The life of each polymer radical is relatively long, and because the polyacetal resin is prone to thermal oxidative decomposition,
The number of polymer radicals in the system is relatively large. When the acrylate derivative according to the present invention is added, since two or more double bonds are contained in one molecule of these acrylate derivatives, these double bonds may be formed under high temperature and high pressure conditions during molding. By trapping the polymer radical of polyacetal, a block copolymer composed of an acrylate derivative and polyacetal is produced, and the decomposition of polyacetal is prevented. Further, the formalin is captured by melamine and the promotion of the thermal oxidative decomposition of the polyacetal by the formalin is suppressed, so that the polyacetal resin is stabilized.

In addition to the polyacetal, the acrylate derivative and the melamine, an alkali metal or alkaline earth metal compound and one or more kinds selected from hydrazide derivatives are added. In this case, the synergistic effect of these substances and melamine is exerted, and the trapping effect of formic acid and formalin generated in the polyacetal resin system by thermal oxidation is enhanced, so that the heat resistance of the polyacetal resin is further improved.

In carrying out the present invention, when the intended polyacetal resin composition is used for ordinary general applications, it is not particularly necessary to select a polyacetal resin having a special quality, and generally, a powder is generally used. The objective can be sufficiently achieved by appropriately selecting from the polyacetal resins commercially available in the form of flakes or flakes in consideration of the application.

In the present invention, the compounding amount of the acrylate derivative (B) is 0.01 to 10.0 parts by weight, more preferably, 100 parts by weight of the polyacetal resin.
It is 0.5 to 3.0 parts by weight. If the blending amount of the acrylate derivative (B) is less than 0.01 parts by weight, the heat stabilizing effect of the polyacetal resin cannot be sufficiently exhibited, and conversely, the blending amount of the acrylate derivative (B) is 10.
If the amount is more than 0 parts by weight, the mechanical properties of the product may be deteriorated in some cases, which is not preferable.

In the present invention, the blending amount of melamine (C) is 0.0 based on 100 parts by weight of the polyacetal resin.
1 to 5.0 parts by weight, more preferably 0.10 to 0.50
Parts by weight. If the blending amount of melamine (C) is less than 0.01 part by weight, a thermal synergistic effect with an acrylate derivative or the like cannot be sufficiently obtained. On the other hand, if the content of melamine (C) is more than 5.0 parts by weight, the mechanical properties of the product may be deteriorated and mold deposit during injection molding may occur, which is not preferable.

When carrying out the present invention, an alkali metal,
Alternatively, the blending amount of the alkaline earth metal compound (D) is 0.
01-1.0 parts by weight, more preferably 0.05-0.5
Is. If the blending amount of the alkali metal or alkaline earth metal compound (D) is less than 0.01 part by weight, the thermal synergistic effect due to the blending cannot be sufficiently exerted, and
On the contrary, if the compounding amount of the alkali metal or alkaline earth metal compound (D) is more than 1.0 part by weight, the resin may be discolored, which is not preferable.

When carrying out the present invention, the blending amount of the hydrazide derivative (E) is 0.01 to 5.0 parts by weight, more preferably 0.1 part by weight with respect to 100 parts by weight of the polyacetal resin.
1 to 3.0 parts by weight. When the compounding amount of the hydrazide derivative (E) is less than 0.01 part by weight, the thermal synergistic effect due to the compounding is small, and conversely, the compounding amount of the hydrazide derivative (E) is less than 5.0 parts by weight. If the amount increases, the mechanical properties of the product deteriorate, which is economically disadvantageous.

Further, when carrying out the present invention, the polyacetal resin composition of the present invention may further contain various antioxidants, light stabilizers, ultraviolet absorbers, lubricants, nucleating agents, carbon black and known compounds if desired. Fillers and pigments,
Two or more kinds of surfactants, antistatic agents and the like can be appropriately used in combination.

When the present invention is carried out, the polyacetal resin composition of the present invention is a melt kneading apparatus which is generally known, more specifically, a single-screw or twin-screw extruder, a kneader, etc., and a pelletizer. Can be easily manufactured. More specifically explaining this,
The polyacetal resin composition of the present invention can be produced, for example, by a generally known method, for example, a polyacetal resin powder (A).
A predetermined amount of an acrylate derivative (B), melamine (C), or an alkali metal or alkaline earth metal compound (D) and a hydrazide derivative (E).
One kind or two or more kinds selected from the above are mixed and mixed uniformly using a super mixer, and then melt-kneaded using a twin-screw extruder or the like, and then pelletized. It is obtained by converting.

The polyacetal composition of the present invention obtained here is easily prepared by a generally known molding method, that is, an injection molding method, an extrusion molding method, a compression molding method, a blow molding method, a vacuum molding method, a foam molding method or the like. Can be molded into.

Hereinafter, the present invention will be specifically and in detail described with reference to examples and comparative examples, and the following examples are for concrete explanation. It is not intended to limit the embodiments of the invention or the scope of the invention.

[0029]

【Example】

Example 1 100 parts by weight of polyacetal resin [manufactured by Mitsubishi Gas Chemical Co., Inc., Iupital, melt index MI10 g / 10 min], 0.10 parts by weight of diethylene glycol dimethacrylate [manufactured by Mitsubishi Gas Chemical Co., Ltd.] and 0.20 part by weight of melamine were uniformly weighed. After mixing it into the sample, weigh 48 g and measure its heat resistance with a Labo Plastomill under the following conditions. Heat resistance is measured by changing the torque of the sample every 5 minutes and by foaming or discoloration after kneading for 30 minutes. The sex was evaluated. The obtained results are shown in Table 2. Measurement conditions of Labo Plastomill Measuring machine: Toyo Seiki 30C150 type Labo Plastomill, test temperature: 220 ° C Z type screw rotation speed: 60 rpm Atmosphere: Air

Examples 2 to 9 All the same measurements as in Example 1 were carried out except that the respective components were mixed in the ratios shown in Table 1 to obtain the results shown in Table 2.

Comparative Examples 1 to 3 The same results as in Example 1 were obtained except that the components were mixed at the ratios shown in Table 3 and the results obtained were shown in Table 4.

Comparative Example 4 Instead of 0.10 parts by weight of diethylene glycol dimethacrylate and 0.20 parts by weight of melamine in Example 1, tetrakis [methylene-3- (3 ', 5'-di-t] was used.
-Butyl-4-hydroxyphenyl) propionate]
Methane [Ciba-Geigy, Irganox101
0] Example 1 except that 0.50 parts by weight was used.
The measurement was performed in the same manner as above, and the obtained results are shown in Table 4.

Comparative Example 5 In Example 1, instead of 0.10 parts by weight of diethylene glycol dimethacrylate, tetrakis [methylene-
3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane [Ciba-Geigy Irganox 1010] 0.50 parts by weight except that all were the same as in Example 1. The results obtained are shown in Table 4.

Examples 10 to 14 All measurements were made in the same manner as in Example 1 except that the components were mixed in the proportions shown in Table 5, and the obtained results are shown in Table 6.

Examples 15 to 22 All measurements were made in the same manner as in Example 1 except that the components were mixed in the proportions shown in Table 7, and the results obtained are shown in Table 8.

Comparative Examples 6 to 8 In Example 1, instead of 0.10 parts by weight of diethylene glycol dimethacrylate, tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4-hydroxyphenyl] was used. ) Propionate] methane [Ciba Geigy, Irganox 1010], triethylene glycol-bis- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate] [Ciba.
0.30 parts by weight of Irganox 245] manufactured by Geigy, 1,6-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionamide] hexane [Irganox 1098 manufactured by Ciba Geigy] is used. In addition, 0.05 part by weight of calcium stearate was added and the measurement was carried out in the same manner as in Example 1. The obtained results are shown in Table 9.
It was shown to.

Comparative Examples 9 to 10 In Example 1, instead of 0.10 parts by weight of diethylene glycol dimethacrylate, tetrakis [methylene-
3- (3 ', 5'-di-t-butyl-4-hydroxyphenyl) propionate] methane [Ciba Geigy, Irganox 1010] 0.50 parts by weight was used in addition to calcium stearate and magnesium hydroxide. 0.05 part by weight was added to each, and measurement was performed in the same manner as in Example 1. The obtained results are shown in Table 9.

[0038]

The polyacetal resin composition of the present invention comprises a polyacetal resin (A), an acrylate derivative (B), a melamine (C), or an alkali metal or alkaline earth metal compound (D), It is a novel polyacetal resin composition obtained by adding and blending one kind or two or more kinds selected from hydrazide derivatives (E) and uniformly melt-kneading. The polyacetal resin composition of the present invention has extremely excellent heat resistance, and also has excellent friction and wear resistance and fatigue resistance of the polyacetal resin that it originally has, and chemical resistance and electrical properties. In particular, since it does not cause discoloration or photosensitization effect due to the antioxidant, it can be suitably used as a material for various polyacetal molded articles.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

[0045]

[Table 7]

[0046]

[Table 8]

[0047]

[Table 9]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C08K 5/3477 (72) Inventor Toshiaki Okuzono 5-6-2 Higashiyawata, Hiratsuka-shi, Kanagawa Gas Chemical Co., Ltd. Plastics Center

Claims (4)

[Claims] 1. An acrylate derivative (B) of 0.01 to 10 parts by weight per 100 parts by weight of the (A) polyacetal resin.
0 parts by weight, (C) melamine 0.01 to 5.0 parts by weight, or (D) alkali metal or alkaline earth metal compound 0.01 to 1.0 parts by weight, (E) hydrazide derivative A polyacetal resin composition obtained by adding and blending one kind or two or more kinds selected from 0.01 to 5.0 parts by weight and uniformly melt-kneading. 2. An acrylate derivative is represented by the following general formula: [R ₁ is hydrogen or a methyl group, and n is an integer of 1 or more. However, when n = 1, R ₂ is an n-valent unsaturated hydrocarbon, and it must contain at least one carbon double bond or triple bond. n ≧
At 2 o'clock, R ₂ is a residue of an n-hydric alcohol]. The polyacetal resin composition according to claim 1. 3. The alkali metal or alkaline earth metal compound is an alkali metal or alkaline earth metal hydroxide, inorganic acid salt, carboxylate, alcohol metal salt, or the like. Polyacetal composition of. 4. A hydrazide derivative is represented by the following general formula: [Chemical 3] [Wherein R ₁ and R ₂ represent a saturated or unsaturated alkyl group, an aryl derivative group, etc., and R ₃ represents a divalent saturated or unsaturated alkyl group, an aryl derivative group, etc.] The polyacetal resin composition according to claim 1, which is