JP3246536B2 - 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 weather (light) resistance and thermal stability. More specifically, the present invention relates to a polyacetal resin, a diene polymer, or one selected from acrylate derivatives, melamine, an alkali metal, or an alkaline earth metal compound, and a light stabilizer. ,
The present invention relates to a polyacetal resin composition having an improved weather (light) resistance, which is added and blended with an ultraviolet absorber and uniformly melt-kneaded.

[0002] The polyacetal resin of the present invention can be used for weathering (light) without impairing the inherent properties of the polyacetal resin.
Highly improved properties and thermal stability, and excellent mechanical properties, so it is used for a long time exposed to sunlight, room lights, etc. It can be awarded as a component, for example, a car out-handle, a wheel cover, a front fender, a component of an electric device, or a material such as a building material or a greenhouse packer.

[0003]

2. Description of the Related Art Polyacetal resin compositions are required to have physical properties such as friction and wear resistance, fatigue resistance, heat resistance and electrical properties, and chemical properties such as chemical resistance and water resistance. Because of its superiority, it has been awarded as a part in the fields of electric / electronics and architecture, as well as in the automobile industry and sundries.

[0004] It is known that polyacetal resin, which is a raw material of the polyacetal resin composition, has poor thermal stability and causes a thermal decomposition reaction in a melt-kneading operation performed at the time of molding. Therefore, various antioxidants, heat stabilizers, and the like are added in order to prevent a thermal decomposition reaction during the molding process.

[0005] When the polyacetal resin is exposed to sunlight or room lights for a long time, especially when exposed to the weather, cracks first occur on the surface, and as the progress proceeds, the gloss is lost and the appearance deteriorates. Then, it is known that, together with the deterioration of the external appearance, the mechanical properties are significantly reduced and the practicality and practical value are lost. In order to prevent the deterioration due to light such as sunlight, a light stabilizer and an ultraviolet absorber are added.

On the other hand, according to various industrial uses, natural pellets prepared by adding and blending an antioxidant and other heat stabilizers, for example, melamine and alkali metal compounds, to a polyacetal resin. In many cases, the polyacetal resin is functionalized by further adding other additives, sub-materials, and the like to the base material. For example, a sliding grade of a polyacetal resin can be produced by adding and kneading a lubricating oil or a silicone oil to the above natural pellets. Further, a flame-retardant grade of a polyacetal resin can be produced by adding and kneading a flame retardant or the like to the above natural pellets.

However, in the case where a weathering (light) resistant grade of a polyacetal resin is produced by adding and kneading a light stabilizer, an ultraviolet absorber and the like to the above natural pellets containing an antioxidant, a light stable Even if a large amount of an agent or an ultraviolet absorber is added, the effect of improving the weather (light) resistance of the polyacetal resin cannot be obtained, and the intended purpose cannot be often achieved. The cause is that the antioxidant present in the resin system captures the polyacetal radical generated by heat or photolysis, and at the same time, generates various quinone compounds by itself, and these quinone compounds are It may cause polyacetal coloring,
In particular, when the added amount of the antioxidant is large, it is decomposed rather and becomes a polyacetal decomposition accelerator. Nevertheless, many of these quinone-based compounds have absorption in the ultraviolet region and have a photosensitizing effect, so that when a polyacetal sample is irradiated with light, its weather (light) resistance rapidly deteriorates. . Further, even when an antioxidant is used in combination with a light stabilizer or an ultraviolet absorber, a chemical reaction occurs between the antioxidant, the light stabilizer, and the ultraviolet absorber, and the light stabilizer and the ultraviolet absorber are consumed. , Polyacetal resin weather resistance (light)
It is thought to decrease the sex. The solution of these problems remains as an industrially important technical problem.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies on polyacetal resin compositions in order to solve the above-mentioned problems. As a result, the polyacetal resin has a diene polymer or an acrylate derivative. When,
Melamine, an alkali metal, or an alkaline earth metal compound, to a natural pellet made by adding and kneading, further adding and blending a light stabilizer, an ultraviolet absorber, etc., and uniformly kneading, Without impairing the excellent friction and wear resistance and fatigue resistance of the original polyacetal resin, and the chemical and electrical properties,
With the knowledge that it is possible to obtain a polyacetal resin composition that is extremely excellent in thermal stability during molding and weather (light) resistance due to the occurrence of cracks and discoloration,
An experiment for confirming technical improvement and reproducibility was performed, and the present invention was completed.

[0009]

According to the present invention, a polyacetal resin is prepared by adding one kind selected from a diene polymer or an acrylate derivative, a melamine, an alkali metal or an alkaline earth metal compound to a polyacetal resin. The present invention relates to a polyacetal resin composition having improved weather (light) resistance, obtained by adding and blending a light stabilizer and an ultraviolet absorber, and uniformly kneading the mixture. More specifically, the present invention relates to (B1) based on 100 parts by weight of the polyacetal resin (A).
0.05 to 5.0 parts by weight of a diene polymer or (B
2) one kind selected from 0.01 to 10.0 parts by weight of an acrylate derivative, (C) melamine 0.01 to
5.0 parts by weight, (D) 0.01 to 1.0 parts by weight of an alkali metal or alkaline earth metal compound, (E) 0.10 to 1.50 parts by weight of a light stabilizer, (F) ultraviolet light The present invention relates to a polyacetal resin composition having improved weather (light) resistance obtained by adding and compounding 0.10 to 1.50 parts by weight of an absorbent and uniformly kneading the mixture.

In the present invention, in the first step, (B1) 0.05 to 5.0 parts by weight of a diene polymer or (B2) with respect to 100 parts by weight of a polyacetal resin.
One kind selected from 0.01 to 10.0 parts by weight of an acrylate derivative, (C) melamine 0.01 to 5.
0 parts by weight, and 0.01 to 1.0 parts by weight of an alkali metal or alkaline earth metal compound (D) are added and blended, and the mixture is uniformly melt-kneaded. In two steps, (E) 0.10 to 1.50 parts by weight of the light stabilizer, based on 100 parts by weight of the polyacetal resin,
(F) A polyacetal resin composition having improved weather (light) resistance, characterized by adding and blending 0.10 to 1.50 parts by weight of an ultraviolet absorber and uniformly melting and kneading.

In the present invention, the polyacetal resin (A) means a polyacetal (polyoxymethylene) and a polyacetal copolymer which are already commercially available. More specifically, for example, formaldehyde or its trimer (trioxane),
And an oxymethylene homopolymer substantially consisting of an oxymethylene unit structure and / or formaldehyde or its trimer (trioxane) produced from its tetramer (tetraoxane), and its tetramer (Tetraoxane) and ethylene oxide, epichlorohydrin, 1,3-dioxolan, 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, formal of glycol, formal of diglycol, and formal of diglycol. A methylene copolymer, or, and an oxymethylene homopolymer, or an oxymethylene copolymer as a main structure, a block structure other than an oxymethylene unit structure, or an oxymethylene block copolymer having a terminal structure, or an oxymethylene graft polymer, or It means a known oxymethylene crosslinked polymer having a crosslinked structure.

The diene polymer (B1) to be added and blended in the present invention is a homopolymer of a conjugated diolefin, or a conjugated diolefin and another conjugated diolefin, an olefin, an aromatic vinyl compound, acrylonitrile, It means that it is a copolymer of one type selected from the group consisting of an acrylate ester and an acetylene compound, or two or more types. More specifically, the conjugated diolefin homopolymer and the copolymer of a conjugated diolefin and another conjugated diolefin include, for example, butadiene, isoprene, 1,3 pentadiene, cyclopentadiene, Homopolymers such as 3-dimethylbutadiene, chloroprene, and 2-phenylbutadiene, and copolymers of these conjugated diolefins can be given. Also, conjugated diolefins, olefins, aromatic vinyl compounds,
Examples of the copolymer composed of an acrylate ester and an acetylene compound include ethylene, propylene, butene-1, isobutylene, pentene-1, hexene-1, heptene-1, octene-1, dodecene-1, and the like.
Styrene, α-methylstyrene, p-hydroxystyrene, acrylonitrile, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-methacrylate
-Butyl, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, dodecyl pentadecyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, Allyl methacrylate,
One type selected from the group consisting of acetylene or the like, or a copolymer of two or more types selected from the above-mentioned conjugated diolefins can be used.

In the present invention, the diene polymer is a natural product, a synthetic product, a degree of polymerization, a physical state, a molecular form, and
It is not limited to a double bond microstructure, ie, carbon-
As long as the carbon double bond is 5% or more of the whole polymer, natural and synthetic products having any degree of polymerization, vinyl group, trans-1,4 structure and cis-1,4 structure at various ratios Any double bond microstructure of the union, 1,2 polymer, 1,4 polymer, any of linear, graft, partial cyclic, block, random, and liquid forms , Powders, flakes, lumps, and pellets in any physical state are included in the present invention.

The acrylate derivative (B2) added / blended in the present invention is represented by the following general formula:

[0015]

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[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
Triple bonds and the like must contain at least one or more. When n ≧ 2, R ₂ is a residue of an n-valent alcohol]. More specifically, for example, unsaturated alkyl acrylate compounds having an acrylate-derived group consisting of various unsaturated alkyls,
Alternatively, ether acrylate compounds having an acrylate-derived group composed of various alkyl glycols, polyalkyl glycols, trimethylolethane, trimethylolpropane, pentaerythritol and the like can be mentioned.

The acrylate derivative of the present invention may be in any physical state such as liquid, powder, flake, lump, and pellet.

In the present invention, the alkali metal or alkaline earth metal compound (D) is a hydroxide or inorganic acid salt of an alkali metal or an alkaline earth metal.
Carboxylates, metal salts of alcohols and the like are meant. More specifically, the hydroxide includes, for example, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide and the like. As inorganic acid salts, for example, sodium, potassium, magnesium, calcium of carbonic acid, phosphoric acid, silicic acid, boric acid,
Barium and other metal salts and the like.
As the carboxylate, a monovalent, divalent, or polyvalent carboxylic acid salt, for example, sodium, potassium, magnesium, calcium, barium such as acetic acid, butyric acid, montanic acid, citric acid, adipic acid, stearic acid, and,
Other metal salts are included. Examples of the metal salt of alcohol include 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 included.

In the present invention, the light stabilizer (E) means a hindered amine compound of a piperidine derivative having steric hindrance or a high molecular weight piperidine-derived polycondensate. More specifically, for example, 4-acetoxy-2,2,6,6-tetramethylpiperidine,
-Stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6
-Tetramethylpiperidine, 4-methoxy-2,2,
6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2, 6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6
-Tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 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) adipate,
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (2,2,2
6,6-tetramethyl-4-piperidyl) terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4)
-Piperidyl) ethane, bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate, bis (1-methyl-2,2,6,6-tetramethyl-4) -Piperidyl) adipate, tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate, dimethyl-1- (2-hydroxyethyl) succinate-4-hydroxy -2,2,6,6-tetramethylpiperidine and the like.

In the present invention, the ultraviolet absorbent (F) is one selected from the group consisting of benzotriazole compounds, benzophenone compounds, aromatic benzoate compounds, cyanoacrylate compounds, and oxalic anilide compounds. The above compounds are meant. More specifically, for example, 2- (2′-hydroxy-5′-
Methyl-phenyl) benzotriazole, 2- (2′-
Hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′,
5'-di-isoamyl-phenyl) benzotriazole, 2- [2'-hydroxy-3 ', 5'-bis-
(Α, α-dimethylbenzyl) phenyl] benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy -4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4- Oxybenzylbenzophenone, 2-hydroxy-4-methoxy-5
Sulfobenzophenone, pt-butylphenyl salicylate, p-octylphenyl salicylate, 2-ethylhexyl-2-cyano-3,3′-diphenylacrylate, ethyl-2-cyano-3,3′-diphenylacrylate, N- ( 2-ethoxy-5-t-butylphenyl) oxalic acid diamide, N- (2-ethylphenyl)-
N '-(2-ethoxyphenyl) oxalic acid diamide and the like can be mentioned.

In the present invention, a diene polymer or an acrylate derivative is limited to a polyacetal resin which has an antagonistic action with a light stabilizer or an ultraviolet absorber when used in combination with or added to the compound. Deterioration of the effect of improving crack generation, and substantially no light-induced discoloration of the polyacetal resin due to the addition of the diene-based polymer or acrylate derivative, and further, the addition of a diene-based polymer or acrylate derivative Is based on the experimental result that the heat resistance of the polyacetal resin is improved.

The diene-based polymer or acrylate derivative of the present invention exhibits excellent crack resistance and weathering (light) resistance-improving effect due to discoloration resistance under the conditions of melting and kneading under the conditions of melt kneading. It is considered that they hardly react with the added ultraviolet absorbers and light stabilizers, that is, they have very little mutual antagonism, and they do not generate coloring or photosensitizing effects such as antioxidants.

In addition, the reason why the heat resistance of the polyacetal resin is improved by adding a diene polymer or an acrylate derivative to the polyacetal resin in the present invention will be described based on experimental results. Can be interpreted as follows. If one point in one polyacetal molecule is oxidatively cleaved by thermal oxidation, two polymer radicals are generated, and a formalin reaction occurs one after another from the radical end of the polymer radical. Is relatively long, and the number of polymer radicals in the system is relatively large because the polyacetal resin is easily decomposed by thermal oxidation. When a diene-based polymer or an acrylate derivative is added, the diene-based polymer or the acrylate derivative contains a large number of double bonds. The heavy bond captures the polymer radical of the polyacetal, thereby generating a diene polymer or a copolymer of an acrylate derivative and the polyacetal, and at the same time, preventing the decomposition of the polyacetal, thereby stabilizing the polyacetal resin.

In addition to the diene polymer or the acrylate derivative, the polyacetal resin further includes
When melamine, an alkali metal or an alkaline earth metal compound is added, a synergistic effect of these compounds is exerted, so that the heat resistance of the polyacetal resin is further improved.

In practicing the present invention, when the intended polyacetal resin composition is generally used for general purposes, it is not particularly necessary to select a polyacetal resin of a special quality. The purpose can be sufficiently achieved by appropriately selecting from among polyacetal resins commercially available in the form of flakes, flakes, or pellets in consideration of their uses.

In the present invention, the diene polymer (B
The amount of 1) is preferably 0.05 to 5.0 parts by weight, more preferably 0.5 to 5.0 parts by weight, based on 100 parts by weight of the polyacetal resin.
3.0 parts by weight. If the blending amount of the diene polymer (B1) is less than 0.05 parts by weight, the effect of stabilizing the heat of the polyacetal resin cannot be sufficiently exhibited, and conversely, the blending amount of the diene polymer (B1) If the content exceeds 5.0 parts by weight, the mechanical properties of the product may be lowered in some cases.

In the present invention, the compounding amount of the acrylate derivative (B2) is more preferably 0.01 to 10.0 parts by weight based on 100 parts by weight of the polyacetal resin.
0.5 to 3.0 parts by weight. Acrylate derivative (B
If the blending amount of 2) is less than 0.01 part by weight, the heat stabilizing effect of the polyacetal resin cannot be sufficiently exhibited, and conversely, the blending amount of the acrylate derivative (B2) is 1%.
If the amount is more than 0.0 parts by weight, the mechanical properties of the product may be deteriorated in some cases, which is not preferable.

In the present invention, the melamine (C) is added in an amount of 0.0 with respect to 100 parts by weight of the polyacetal resin.
It is more preferably 1 to 5.0 parts by weight, but more preferably 0.10 to 0.50 parts by weight. If the amount of the melamine (C) is less than 0.01 parts by weight, the synergistic effect with the diene polymer or the acrylate derivative cannot be sufficiently exerted. If the amount is more than 5.0 parts by weight, it is not preferable because the mechanical properties of the molded article decrease and the amount of mold deposit generated during molding increases.

In the present invention, the compounding amount of the alkali metal or alkaline earth metal compound (D) is 0.01 to 1.0 part by weight, preferably 0.05 to 0 part by weight, per 100 parts by weight of the polyacetal resin. .50 parts by weight.
Alkali metal or alkaline earth metal compound (D)
Is less than 0.01 part by weight, a synergistic effect with a diene polymer or an acrylate derivative or melamine cannot be obtained. Conversely, when the compounding amount of the alkali metal or alkaline earth metal compound (E) is 1.0%
If the amount is more than the weight part, coloring of the molded article and a decrease in weather (light) resistance occur, which is not preferable.

In the present invention, the light stabilizer (E) is compounded in an amount of 0.1 to 100 parts by weight of the polyacetal resin.
0 to 1.50 parts by weight, more preferably 0.10 to 0.5
0 parts by weight. When the compounding amount of the light stabilizer (E) is 0.10
When the amount is less than 1 part by weight, the synergistic effect with the ultraviolet absorber cannot be sufficiently exerted. On the contrary, when the amount of the light stabilizer (E) is more than 1.50 parts by weight, the bleed-out and the like are caused. This leads to poor appearance of the molded article and a decrease in mechanical properties, which is not preferable.

In the present invention, the compounding amount of the ultraviolet absorber (F) is preferably 0.10 to 1.50 parts by weight, more preferably 0.10 to 1.50 parts by weight, based on 100 parts by weight of the polyacetal resin.
0.50 parts by weight. If the amount of the ultraviolet absorber (F) is less than 0.10 parts by weight, sufficient weather resistance (light) is obtained.
I can not get the nature. Conversely, if the amount of the ultraviolet absorber (F) is more than 1.50 parts by weight, the coloring of the molded product and the mechanical properties are deteriorated, which is economically disadvantageous.

When carrying out the present invention, the polyacetal resin composition of the present invention may further contain carbon black, a known filler, a pigment, a surfactant,
One or more kinds of antistatic agents, lubricants, nucleating agents and the like can be appropriately added as long as the effects of the present invention are not impaired.

In practicing the present invention, the polyacetal resin composition of the present invention may be mixed with a generally known melt-kneading apparatus, more specifically, a single-screw or twin-screw extruder or kneader, and the like. It can be easily manufactured using a pelletizer. To explain this more specifically, the polyacetal resin composition of the present invention can be prepared by adding a predetermined amount of a diene polymer (B1) to a generally available polyacetal resin powder (A) according to a generally known method. ) Or acrylate derivative (B2), melamine (C), and alkali metal or alkaline earth metal compound (D) are added and blended and uniformly mixed using a super mixer or the like, and then biaxially mixed. The mixture is melt-kneaded using an extruder or the like and pelletized. After drying the obtained pellets, a predetermined amount of a light stabilizer (E) and an ultraviolet absorber (F) are added and blended to 100 parts by weight of the polyacetal resin, and the mixture is uniformly blended with a blender. After mixing, the mixture is melt-kneaded using a twin-screw extruder and pelletized.

The obtained polyacetal composition of the present invention is excellent in thermal stability at the time of injection molding, and is therefore generally known in molding methods, that is, injection molding, extrusion molding, compression molding, and blow molding. It can be easily formed by a molding method, a vacuum molding method, a foam molding method, or the like.

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

[0036]

【Example】

Example 1 100 parts by weight of a polyacetal resin (Mitsubishi Gas Chemical, Iupital, melt index MI 10 g / 10 min)
0.10 parts by weight of triethylene glycol dimethacrylate (manufactured by Mitsubishi Gas Chemical), 0.20 parts by weight of melamine, and 0.05 parts by weight of calcium stearate were weighed and uniformly mixed using a super mixer (manufactured by Kawada Seisakusho). Later
Twin screw extruder [Ikegai Iron Works, PCM-30,
Screw diameter 30 mm] and the screw rotation speed 5
After melt-kneading under the conditions of 0 rpm and a cylinder set temperature of 220 ° C., the mixture was pelletized. Subsequently, the pellets were dried using a hot air dryer at a temperature of 80 ° C. for 2 hours, and then bis- [N-methyl-2,2,6,6-tetramethyl-4 was added to 100 parts by weight of the polyacetal resin. −
Piperidinyl] sebacate [SANOL, manufactured by Sankyo Chemical Co., Ltd.
LS765] 0.35 parts by weight, 2- [2'-hydroxy-3 ', 5'-bis (α, α-dimethylbenzyl) phenyl] benzotriazole [manufactured by Ciba-Geigy, T
Inuvin 234] 0.35 parts by weight were weighed and uniformly mixed with a tumbler (manufactured by Matsui Seisakusho), and then melt-kneaded again using a twin screw extruder under the conditions of a screw rotation speed of 80 rpm and a cylinder set temperature of 200 ° C. And pelletized. The pellets obtained here were dried for 4 hours using a hot-air dryer at a temperature of 80 ° C., and then strip-shaped test pieces were injected using an injection molding machine (manufactured by Sumitomo Heavy Industries, Model SG125, theoretical injection capacity 163 ml). [Size 3.2 × 12.7 × 6
3.6 mm] [Operation conditions: mold temperature 80 ° C., cylinder set temperature 200 ° C., injection pressure 800 kg / c
m ² , molding cycle 40 seconds]. The strip-shaped test piece obtained here was used as a weather meter [manufactured by Suga Test Instruments, WBL-
SUN-HCH type], and the treatment was performed under the conditions of a black panel temperature of 83 ° C. and no rain spray. The strip-shaped test piece was taken out of the tester every 50 hours and observed for discoloration, cracks and bleed-out. At 800 hours, cracks were observed on the test piece surface [Cracks] Time of occurrence]. No discoloration or bleed-out of the additive on the surface of the test piece was observed. Table 1 shows the results.

Example 2 The procedure of Example 1 was repeated, except that the amount of triethylene glycol dimethacrylate was changed from 0.10 part by weight to 0.50 part by weight. The result shown in FIG.

Examples 3 to 5 In Example 1, the amount of triethylene glycol dimethacrylate was changed from 0.10 part by weight to 1.0
All treatments were carried out in the same manner as in Example 1 except that the amounts were changed to 3.0 and 10.0 parts by weight, and the results shown in Table 1 were obtained.

Examples 6 and 7 In Example 1, instead of 0.10 parts by weight of triethylene glycol dimethacrylate, 1.0 part by weight of diethylene glycol dimethacrylate (manufactured by Mitsubishi Gas Chemical Co., Ltd.) and allyl methacrylate [ Except that 1.0 part by weight of Mitsubishi Gas Chemical Co., Ltd. was used, all treatments were carried out in the same manner as in Example 1 to obtain the results shown in Table 1.

Example 8 The procedure of Example 1 was repeated except that in place of 0.10 parts by weight of triethylene glycol dimethacrylate, 0.05 parts by weight of polybutadiene (Nippon Petrochemical Co., Ltd., B-2000) was used. By performing the same treatment as in Example 1, the results shown in Table 1 were obtained.

Examples 9 to 11 In Example 1, instead of 0.10 parts by weight of triethylene glycol dimethacrylate, an acrylonitrile / butadiene / styrene copolymer (JSR12, manufactured by Nippon Synthetic Rubber Co., Ltd.) 0.50, Except that 1.0 and 5.0 parts by weight were used, all were treated in the same manner as in Example 1,
The results shown in Table 1 were obtained.

Example 12 Example 12 was the same as Example 1 except that 0.50 parts by weight of polybutadiene [Example 8] was used instead of 0.10 parts by weight of triethylene glycol dimethacrylate. And the results shown in Table 1 were obtained.

Example 13 In Example 1, the amount of triethylene glycol dimethacrylate was changed from 0.10 part by weight to 0.5 part by weight, and bis- [N-methyl-2,2,6 Instead of 0.35 parts by weight of 2,6-tetramethyl-4-piperidinyl] sebacate, bis- [2,2,6,6-tetramethyl-4-piperidinyl] sebacate [manufactured by Sankyo Chemical Co., Ltd., SA
NOL LS770] 0.35 parts by weight, bis- [2,2,6,6-tetramethyl-4-piperidinyl] sebacate and 2- [2'-hydroxy-
When mixing 3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] benzotriazole, 0.05 parts by weight of liquid paraffin was used based on 100 parts by weight of the pellet obtained in the first step. Except for the above, all treatments were performed in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Example 14 In Example 1, 0.10 parts by weight of triethylene glycol dimethacrylate and bis- [N-methyl-2,2,2 were added.
Instead of 0.35 parts by weight of 6,6-tetramethyl-4-piperidinyl] sebacate, 0.50 parts by weight of an acrylonitrile / butadiene / styrene copolymer [Example 9] and bis- [2,2,6 6-tetramethyl-4-piperidinyl] sebacate 0.35 parts by weight,
Bis- [2,2,6,6-tetramethyl-4-piperidinyl] sebacate and 2- [2′-hydroxy-3 ′,
When 5′-bis (α, α-dimethylbenzyl) phenyl] benzotriazole is mixed, 100 parts by weight of the pellet obtained in the first step is mixed with 0.1 part of liquid paraffin.
Except for using 05 parts by weight, all treatments were performed in the same manner as in Example 1 to obtain the results shown in Table 1.

Example 15 In Example 1, 0.10 parts by weight of triethylene glycol dimethacrylate and bis- [N-methyl-2,2,2 were added.
6,6-tetramethyl-4-piperidinyl] sebacate instead of 0.35 parts by weight, diethylene glycol dimethacrylate [Example 6] 0.50 parts by weight and bis-
[2,2,6,6-tetramethyl-4-piperidinyl]
In addition to using 0.35 parts by weight of sebacate,
[2,2,6,6-tetramethyl-4-piperidinyl]
When sebacate is mixed with 2- [2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] benzotriazole, 100 parts by weight of the pellet obtained in the first step is mixed with liquid Except for using 0.05 parts by weight of paraffin, all were treated in the same manner as in Example 1,
The results shown in Table 1 were obtained.

Example 16 In Example 1, the amount of triethylene glycol dimethacrylate was changed from 0.10 part by weight to 0.50 part by weight, and bis- [N-methyl-2,2,6, , 6-
Tetramethyl-4-piperidinyl] sebacate 0.35
Instead of parts by weight, 0.35 parts by weight of bis- [2,2,6,6-tetramethyl-4-piperidinyl] sebacate and 2- [2′-hydroxy-3 ′, 5′-bis ( Instead of 0.35 parts by weight of α, α-dimethylbenzyl) phenyl] benzotriazole, methyl-3- [3-
Condensation product with t-butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate-polyethylene glycol [manufactured by Ciba-Geigy,
Tinuvin 213], except that 0.35 parts by weight was used, and all the treatments were carried out in the same manner as in Example 1 to obtain the results shown in Table 1.

Comparative Example 1 100 parts by weight of a polyacetal resin (Mitsubishi Gas Chemical, Iupital, melt index MI 10 g / 10 min)
Melamine 0.20 parts by weight, calcium stearate 0.
After weighing out 05 parts by weight and uniformly mixing using a super mixer (manufactured by Kawada Seisakusho), using a twin-screw extruder (manufactured by Ikegai Iron Works, PCM-30, screw diameter 30 mm),
Screw rotation speed 50 rpm, cylinder set temperature 22
When melt-kneaded and pelletized at 0 ° C., the sample was foamed and decomposed, so that the light-fast formulation in the second stage was not performed (see Table 2).

Comparative Example 2 Example 1 was repeated except that the amount of triethylene glycol dimethacrylate was changed from 0.10 part by weight to 15.0 parts by weight. Table 2
Were obtained.

Comparative Examples 3 and 4 In Example 1, an acrylonitrile / butadiene / styrene copolymer [Example 9] was used instead of 0.10 parts by weight of triethylene glycol dimethacrylate.
Example 1 except that 0.0 and 15.0 parts by weight were used.
And the results shown in Table 2 were obtained.

Comparative Example 5 The procedure of Example 1 was repeated, except that 0.10 parts by weight of triethylene glycol dimethacrylate was replaced by triethylene glycol-bis- [3- (3-tert-butyl-4-hydroxy-hydroxy).
[5-Methylphenyl) propionate] [Ir245, manufactured by Ciba-Geigy Co.] In addition to changing the amount to 0.50 parts by weight, the same treatment as in Example 1 was carried out, and the results shown in Table 2 were obtained.

Comparative Examples 6 to 8 In Example 1, instead of 0.10 parts by weight of triethylene glycol dimethacrylate, triethylene glycol-bis- [3- (3-tert-butyl-4-hydroxy-5) was used. -Methylphenyl) propionate] [Ir245, manufactured by Ciba-Geigy Corporation], n-octadecyl-3
-(3,5-di-t-butyl-4-hydroxyphenyl) propionate [AO5 manufactured by Adeka Argus Co., Ltd.
0], and tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane [Ir1010, manufactured by Ciba-Geigy Corporation]
Except that 0.30 parts by weight were used, all treatments were performed in the same manner as in Example 1 to obtain the results shown in Table 2.

[0052]

The polyacetal resin composition of the present invention comprises a polyacetal resin (A) and a diene polymer (B
1) or one selected from acrylate derivatives (B2), melamine (C), an alkali metal,
Alternatively, an alkaline earth metal compound (D), a light stabilizer (E), and an ultraviolet absorber (F) are added and blended, and the mixture is uniformly melt-kneaded to improve the weather (light) resistance of the polyacetal. It is a resin composition. In the first step, the polyacetal resin composition of the present invention is a polyacetal resin (A), which is one type selected from diene polymers (B1) and acrylate derivatives (B2), and melamine. (C) and an alkali metal or alkaline earth metal compound (D) are added and blended, uniformly melt-kneaded, and the resulting pellets are further mixed with a light stabilizer (E) in a second step. A polyacetal resin composition having improved weather resistance (light), characterized by adding and blending an ultraviolet absorber (F) and a uniform melt-kneading.

The polyacetal resin composition of the present invention comprises:
In particular, a diene polymer (B1) or one selected from acrylate derivatives (B2), a melamine (C), an alkali metal or an alkaline earth metal compound (D), etc. are added and blended. Then, using the natural pellets made as a base material, and further adding and blending a light stabilizer (E) and an ultraviolet absorber (F) to produce a weather (light) resistant grade, discoloration due to an antioxidant, light Since there is no sensitizing action and no consumption reaction of the light stabilizer or ultraviolet absorber by the antioxidant, it has extremely excellent weather (light) resistance, for example, cracking resistance, light discoloration resistance, and heat stability. Therefore, it can be suitably used as a material for various polyacetal molded articles requiring extremely excellent weather (light) resistance, particularly weather (light) resistance due to crack generation and discoloration.

[0054]

[Table 1]

[0055]

[Table 2]

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-81242 (JP, A) US Patent 3,975,459 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 59 / 00-59/04

Claims (7)

(57) [Claims] 1. (A1) 0.05 to 5.0 parts by weight of a diene polymer or (B2) 0.01 to 100 parts by weight of a polyacetal resin with respect to 100 parts by weight of a polyacetal resin.
One kind selected from 10.0 parts by weight, (C)
Melamine 0.01 to 5.0 parts by weight, (D) an alkali metal or alkaline earth metal compound 0.01 to 1.0 part by weight
Parts by weight, (E) 0.10 to 1.50 parts by weight of a light stabilizer,
(F) A polyacetal resin composition having improved weather (light) resistance obtained by adding and blending 0.10 to 1.50 parts by weight of an ultraviolet absorber and uniformly melting and kneading. 2. In the first step, (B1) a diene-based polymer is added to 100 parts by weight of the polyacetal resin (A).
5 to 5.0 parts by weight, or (B2) one kind selected from 0.01 to 10.0 parts by weight of an acrylate derivative, (C) 0.01 to 5.0 parts by weight of melamine, and , (D) 0.01 to 1.0 parts by weight of an alkali metal or alkaline earth metal compound is added and blended, uniformly melt-kneaded, and then formed into pellets.
To 100 parts by weight of the polyacetal resin, (E) 0.10 to 1.50 parts by weight of a light stabilizer and (F) 0.10 to 1.50 parts by weight of an ultraviolet absorber are added and blended, and the mixture is uniformly mixed. The polyacetal resin composition according to claim 1, wherein the composition is melt-kneaded. 3. The diene polymer is a homopolymer of a conjugated diolefin, or a group consisting of a conjugated diolefin and another conjugated diolefin, an olefin, an aromatic vinyl compound, acrylonitrile, an acrylate ester, and an acetylene compound. one kind selected from, or a copolymer der Ru請 Motomeko 1 Symbol placement of the polyacetal resin composition with that of two or more. 4. An acrylate derivative 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, which must contain at least one carbon double bond or triple bond. n ≧
At 2, R ₂ is according to claim 1 Symbol placement of the polyacetal resin composition in which indicated by a is] residue of n-valent alcohol. 5. The alkali metal or alkaline earth metal compound is an alkali metal, or alkaline earth metal hydroxides, inorganic acid salts, carboxylates, claim 1 Symbol mounting an alcohol of metal salts Polyacetal resin composition. 6. The light stabilizer is a piperidine derivative having a steric hindrance, and, or, according to claim 1 Symbol placement of the polyacetal resin composition is a piperidine derived polycondensate molecular weight. 7. The ultraviolet absorber is one or more compounds selected from benzotriazole-based compounds, benzophenone-based compounds, aromatic benzoate-based compounds, cyanoacrylate-based compounds, and oxalic anilide-based compounds. claim 1 Symbol placement of the polyacetal resin composition is.