JPH05295231A - Matte and weather-resistant polyacetal resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject new composition excellent in both matting characteristics and weather resistance by blending a polyacetal resin with a specific multiphase interpolymer, a specified ultraviolet ray absorber and a specific light stabilizer. CONSTITUTION:The objective composition is obtained by blending (A) 100 pts.wt. polyacetal resin with (B) 1-100 pts.wt. multiphase interpolymer having a multiphase structure of two or more phases composed of the repetition of soft phases and hard phases from the central phase to the outermost phase, (C) 0.01-5 pts.wt. ultraviolet ray absorber selected from benzotriazole-based and oxalanilide-based ultraviolet ray absorbers {preferably 2-[2'-hydroxy-3',5'-bis-(alpha,alpha-dimethylbenzyl) phenyl]benzotriazole} and (D) 0.01-5 pts.wt. hindered amine-based light stabilizer (preferably 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, etc.]. The hard layer is preferably a polymer composed of methyl methacrylate and the soft layer is a polymer composed of butadiene as the component (B).

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, and more particularly to a polyacetal resin composition excellent in both matting property and weather resistance.

[0002]

2. Description of the Related Art Polyacetal resins are plastics that are widely used as engineering resins in various fields, especially in the fields of automobiles and home appliances, because they have excellent mechanical properties and molding processability. However, the molded product of polyacetal resin has high surface gloss, and when used in automobile interior parts, etc., it may be a major obstacle such as impairing the sense of quality, and the matte property of the molded product is required. ing.

As a method for providing the matte property of a molded product, a method of subjecting the surface of the mold to a texture treatment and transferring it to the surface of the molded product and a method of applying a matte coating are known, but the former is sufficiently matte. The effect is not obtained, and in the case of coating, there is a problem such as environmental pollution by a solvent, which is not preferable. On the other hand, various methods of delustering the resin itself have been investigated, and a method of blending a rubber polymer in a resin matrix or an inorganic filler (Japanese Patent Laid-Open No. 64-54053 and Japanese Patent Laid-Open No. 1-54053). 170641 and Japanese Patent Laid-Open No. 1-319561
No. publication) is known. In the former case, in order to maintain and improve the impact resistance of the molded product, it is often used in ABS resin and the like, but the heat resistance may decrease, so that a polyacetal resin composition having excellent heat resistance can be obtained. Is not the preferred method.

There are many known inorganic fillers to be filled in the polyacetal resin. Further, the polyacetal resin composition containing such an inorganic filler results in fine irregularities on the surface of the molded product, which diffusely reflects the irradiated light and can realize a matte effect, but the degree of the effect is Not enough. Further, the polyacetal resin composition has a drawback that mechanical properties, particularly elongation and toughness are extremely deteriorated and the original characteristics of the polyacetal resin are impaired.

On the other hand, as a method of adding the multiphase interpolymer to the polyacetal resin, a method of adding an acrylic multiphase interpolymer having a two-phase structure to the polyacetal resin (JP-A-9-136343), -2
A method of adding a rubber elastic graft copolymer having a glass transition temperature of 0 ° C. or less to an acetal polymer (Japanese Patent Publication No.
No. 34830), and a method of adding a rubber elastic graft polymer having butadiene to a polyacetal resin (Japanese Patent Laid-Open No. 1-120849), all of the compositions obtained by the above method are essentially polyacetal resins. Has a problem that mechanical properties (particularly strength and elasticity) are greatly impaired, and thermal stability at the time of molding is insufficient.

Moreover, none of the compositions obtained by the above method is intended for matting properties, the degree of matting effect is not sufficient, and the weather resistance is also insufficient. Further, Japanese Patent Laid-Open No. 2-294352 discloses a composition obtained by blending a polyacetal resin with a multiphase interpolymer and a methacrylic acid ester-based polymer, but the composition only improves the weather resistance. It was intended, and did not have sufficient matte properties.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyacetal resin composition which overcomes the above-mentioned drawbacks of the prior art and simultaneously achieves sufficient matting properties and weather resistance.

[0008]

Means for Solving the Problems As a result of intensive studies made by the present inventors in order to solve the above problems, as a result, (1) a multiphase interpolymer having a specific composition in a polyacetal resin,
A polyacetal resin composition obtained by adding (2) a specific ultraviolet absorber and (3) a specific light stabilizer has extremely excellent matting properties and weather resistance, and impairs the mechanical properties inherent to the polyacetal resin. The present invention has been achieved by finding out that there is nothing.

That is, the present invention relates to a polyacetal resin 10
1 to 100 parts by weight of a multi-phase interpolymer having a multi-phase structure consisting of repeating soft and hard phases from the central phase to the outermost phase, relative to 0 parts by weight, selected from benzotriazole type and anilide oxalate type The present invention provides a polyacetal resin composition containing 0.01 to 5 parts by weight of at least one UV absorber and 0.01 to 5 parts by weight of a hindered amine light stabilizer.

The present invention will be described in detail below. The polyacetal resin used in the composition of the present invention is a oxymethylene unit produced from a cyclic oligomer such as a formaldehyde monomer or its trimer (trioxane) or tetramer (tetraoxane). An oxymethylene homopolymer having 2 to 8 carbon atoms, which is produced from the above-mentioned raw material and a cyclic ether such as ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolane, glycol formal, and diglycol formal. Is an oxymethylene copolymer containing 0.1 to 20% by weight. It also includes oxymethylene copolymers having branched molecular chains and oxymethylene block copolymers containing 50% by weight or more of repeating units of oxymethylene and less than 50% by weight of different polymer units.

The multiphase interpolymer which can be used in the present invention is a multiphase interpolymer having a multiphase structure of two or more phases composed of repeating soft phase and hard phase from the central phase to the outermost phase. .. For example, a multi-phase interpolymer having a two-phase structure, an elastomer phase which is a soft phase in a first phase which is a central phase, and a hard phase which is a second phase which is an outermost phase can be used in the present invention. ..

Further, it may be a multiphase interpolymer having an epoxy group or a hydroxyl group in its outermost phase.
The glass transition temperature (hereinafter abbreviated as Tg) of the polymer constituting the soft phase is preferably less than 25 ° C, more preferably less than 0 ° C. On the other hand, the Tg of the polymer constituting the hard phase is preferably 25 ° C. or higher, more preferably 50 ° C. or higher.

In the case of a three-phase structure, for example, the first phase (central phase) and the third phase (outermost phase) are hard phases, the second phase (central phase) is an elastomer phase, and the soft phase is The Tg of the constituting polymer is preferably less than 25 ° C, more preferably less than 0 ° C. Tg of the polymer constituting the hard phase is 2
It is preferably 5 ° C or higher, more preferably 50 ° C or higher. Furthermore, in order to improve the interfacial adhesion between the polyacetal resin and the multiphase interpolymer, the outermost phase of these multiphase interpolymers may have a functional group such as an epoxy group, a hydroxyl group or a carboxyl group.

The soft phase and hard phase of the multiphase interpolymer are specifically composed of homopolymers of the following monomers or copolymers of two or more kinds of monomers. Examples of usable monomers include aromatic vinyl monomers such as styrene, p-methylstyrene and α-methylstyrene; halogenated vinyl monomers such as vinyl chloride and vinylidene chloride; acrylonitrile,
Nitrile type monomers such as methacrylonitrile; methacrylic acid esters such as methyl methacrylate, butyl methacrylate and hydroxy methacrylate.
Methyl acrylate, ethyl acrylate, acrylic acid n-
Acrylic esters such as butyl, 2-ethylhexyl acrylate, dodecyl acrylate, hydroxyethyl acrylate; allyl acrylate, allyl methacrylate, etc., which have two or more double bonds in one molecule; acetic acid Examples thereof include vinyl esters such as vinyl and vinyl propionate; unsaturated amides such as acrylamide and methacrylamide; vinyl alkyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether; conjugated dienes such as butadiene and isoprene.

The soft phase of the multiphase interpolymer is preferably a polymer or copolymer of acrylic acid ester, methacrylic acid ester, or conjugated diene, and further, n-butyl acrylate, 2-ethylhexyl acrylate, Alternatively, a polymer or copolymer made of styrene butadiene is more preferable. The hard phase of the multiphase interpolymer is preferably a polymer composed of an acrylic ester, a methacrylic ester, an aromatic vinyl, or a vinyl halide, and further, methyl acrylate or methacrylic acid. Polymers consisting of methyl or styrene or vinyl chloride are preferred.

The preferred combination of polymers constituting the hard phase and soft phase in the multiphase interpolymer is, for example,
The hard phase is a polymer containing methyl methacrylate as a main component, and the soft phase is a polymer containing 2-ethylhexyl acrylate as a main component; the hard phase is a polymer containing methyl methacrylate as a main component, and Examples include polymers in which the soft phase is mainly composed of n-butyl acrylate; polymers in which the hard phase is mainly composed of methyl methacrylate and in which the soft phase is styrene-butadiene or butadiene.

The ratio of the hard phase and the soft phase in the multiphase interpolymer is not particularly limited, but preferably the hard phase 10
The range of 50 to 50% by weight and the soft phase of 90 to 50% by weight are preferable.
The epoxy group or hydroxyl group introduced into the outermost phase is usually obtained by copolymerizing a monomer constituting the outermost phase with a vinyl monomer having an epoxy group or a hydroxyl group.

As the vinyl monomer having an epoxy group, for example,

[0019]

[Chemical 1]

There is a glycidyl ester of an α, β-unsaturated acid represented by Specifically, glycidyl acrylate,
Glycidyl methacrylate, glycidyl ethacrylate, and the like, and glycidyl methacrylate is more preferable. As the vinyl monomer having a hydroxyl group, for example,
There are hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxyisopropyl acrylate, hydroxyisopropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, etc. Ethyl, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate are more preferable.

The vinyl monomers having these epoxy groups and hydroxyl groups are not particularly limited to these. In addition, the amount of the vinyl monomer having an epoxy group and a hydroxyl group which is copolymerized with the monomer forming the outermost phase is 0.5 with respect to the total monomer forming the multiphase interpolymer.
-10.0% by weight is desirable, and the most preferable addition amount is 1.0-5.0% by weight in terms of matting properties.

The most preferable multiphase interpolymer is a copolymer in which the outermost hard phase of the multiphase interpolymer is 80% by weight or more of methyl methacrylate and 20% by weight or less of another copolymerizable monomer. A two-phase structure composed of a polymer having a soft phase as an internal phase, which is obtained by copolymerizing 80% by weight or more of 2-ethylhexyl acrylate and 20% by weight or less of another copolymerizable monomer. An interpolymer of: an outermost hard phase composed of a copolymer of 80% by weight or more of methyl methacrylate and 20% by weight or less of another copolymerizable monomer,
A polymer obtained by copolymerizing 50% by weight or more of 2-ethylhexyl acrylate, 20% by weight or more of n-butyl acrylate, and 30% by weight or less of other copolymerizable monomer as a soft phase of the inner phase, There is a two-phase structure interpolymer formed from

The multiphase interpolymer in the present invention is disclosed in JP-B-55-27576 or JP-A-59-
It can be produced using a conventional emulsion polymerization technique described in JP-A-136343. A specific example of the production of a multi-phase interpolymer having a two-phase structure is as follows. In water containing an emulsifier such as sodium dioctylsulfosuccinate, the above-mentioned monomer necessary for forming a soft phase and diisopropylbenzene hydroperoxide are used. Polymerization is carried out at a usual temperature of 50 to 90 ° C. with stirring by adding a polymerization initiator. At this time, in order to impart appropriate elasticity to the soft phase, it is preferable to copolymerize a polyfunctional crosslinking agent such as a divinyl compound. The amount of the polyfunctional crosslinking agent added is preferably 0.1 to 5.0% by weight based on the total weight of the polymer constituting the soft phase. Further, in this case, it is preferable to use a polyfunctional grafting agent such as allyl of acrylic acid in order to chemically bond between the hard phase and the soft phase. The amount of the polyfunctional grafting agent added is 0.1-5.0 based on the total weight of the polymer constituting the soft phase.
Weight percent is preferred.

When the polymerization reaction forming the soft phase is completed, the monomer forming the hard phase and the vinyl monomer having an epoxy group or a hydroxyl group are then additionally added. At this time, a polymerization initiator can be additionally added. The multiphase polymer obtained by the emulsion polymerization can be separated from water while maintaining the particle form by using a conventional means such as salting out, freeze-thawing, or spray drying.

In the case of a multi-phase interpolymer having a three-phase structure, first, the monomer forming the central phase and the polyfunctional grafting agent are first polymerized, and then the intermediate phase which is the soft phase and then the hard phase are hardened by the above-mentioned method. It suffices to polymerize in order of the outermost phase which is a phase. The soft phase or hard phase of the present invention may be a uniform phase having the same monomer composition, or may be a phase having two or more layers having different monomer compositions.

The particle size of the multiphase interpolymer is preferably 1 μm or less from the viewpoint of matting properties. The optimum particle size is 0.5
μ to 0.05 μ. The addition amount of the multiphase interpolymer used in the present invention is 1 to 100 parts by weight with respect to 100 parts by weight of the polyacetal resin. This is because if the amount is less than 1 part by weight, these addition effects do not appear on the matte properties, and if the amount exceeds 100 parts by weight, the moldability of the polyacetal resin is significantly reduced. Among them, the preferable range for maximizing the effect of the present invention is 2 to 20 parts by weight, and the most preferable range is 4 to 15 parts by weight.

As the multiphase interpolymer, those containing less alkali metals and sulfur compounds as impurities are preferably used in view of thermal stability of the composition. The alkali metal and the sulfur compound referred to in the present invention are lithium dodecylbenzenesulfonate used in the production of a multiphase interpolymer,
This is due to a sulfonate such as soda or potassium, an emulsifier such as lithium lauryl sulfate, a sulfate ester salt such as sodium and potassium, and a salting-out agent such as sodium sulfate and sodium chloride.

That is, the alkali metal in the present invention means lithium, potassium and sodium. The content of the alkali metal in the multiphase interpolymer can be quantified by a general method, among which the atomic absorption method or the plasma emission method can be used. In the present invention, quantification was performed using the atomic absorption method. That is, this is a method of subjecting the multiphase interpolymer to carbonization or ashing, and extracting the alkali metal content from it with an aqueous acid solution and subjecting it to atomic absorption.

The content of the alkali metal in the present invention is the total of the alkali metals (lithium, potassium, sodium) analyzed by the atomic absorption method and needs to be 100 ppm or less with respect to the multiphase interpolymer.
Preferably 80 ppm or less, more preferably 60 pp
m or less. The sulfur content in the multiphase interpolymer can be quantified by a general method, of which the ion chromatography method is preferable. In the present invention, this ion chromatography method was used for quantification.
That is, it is a method in which a multiphase interpolymer is burned by a flask burning method, and a liquid obtained by extracting a sulfur content with an alkaline aqueous solution is subjected to ion chromatography.

The sulfur content in the present invention is calculated by converting the total amount of sulfur compounds analyzed by ion chromatography into the amount of elemental sulfur, and is required to be 200 ppm or less with respect to the multiphase interpolymer. Preferably 150 ppm or less, more preferably 100 ppm
It is below. The ultraviolet absorber used in the composition of the present invention is selected from benzotriazole type and anilide oxalate type ultraviolet absorbers.

Examples of the benzotriazole type 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] benzotriazole, 2-
(2'-hydroxy-4'-octoxyphenyl) benzotriazole etc. are mentioned.

On the other hand, examples of the anilide oxalic acid type ultraviolet absorber include 2-ethoxy-2'-ethyl oxalic acid bisanilide and 2-ethoxy-5-t-butyl-2'-ethyl oxalic acid bis. Anilid,
2-ethoxy-3'-dodecyl oxalic acid bisanilide and the like can be mentioned. Among these ultraviolet absorbers, 2- [2'-hydroxy-3 ', 5'-bis-
(Α, α-Dimethylbenzyl) phenyl] benzotriazole is particularly preferred. These ultraviolet absorbers may be used alone or in combination of two or more kinds.

The amount of the benzotriazole-based and anilide oxalate-based UV absorbers added to the composition of the present invention is 0.01 to 5 relative to 100 parts by weight of the polyacetal resin.
Parts by weight, preferably 0.05 to 2 parts by weight, more preferably 0.1 to 1.5 are selected. This addition amount is 0.
If it is less than 01 parts by weight, the weather resistance of the obtained composition is insufficient, and if it exceeds 5 parts by weight, the thermal stability of the obtained composition is lowered, and silver streaks and retention are caused during molding. It is not preferable because coloring tends to occur.

The hindered amine light stabilizer used in the composition of the present invention is preferably selected from the following two kinds of light stabilizers. The first of the preferred hindered amine light stabilizers is the general formula:

[0035]

[Chemical 2]

[Wherein R is a general formula:

[0037]

[Chemical 3]

(Wherein Y represents a hydrogen atom, a hydroxyl group, an alkyl group or an acyl group), and X is a piperidine derivative.

[0039]

[Chemical 4]

Where m is 1 to 4 and n is 1 to 10. ] It has a structure represented by. The general formula (I)
In, R is a general formula:

[0041]

[Chemical 5]

It is an N-substituted 2,2,6,6-tetramethylpiperidine residue represented by and is introduced via an ester bond. The number of R contained in one molecule is determined by m and n, and the minimum is 46 when m and n are 4 and 10. As described above, the hindered amine light stabilizer represented by the general formula (I) has N- in the molecule.
By having a large number of substituted 2,2,6,6-tetramethylpiperidine residues, it exerts an excellent effect as a light stabilizer.

Y in the general formula (II) is a hydrogen atom, an oxyl group, an alkyl group or an acyl group,
They may have a substituent. Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, amyl group, hexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl group,
Examples thereof include a decyl group, an octadecyl group, a benzyl group, a phenylethyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 2-hydroxybutyl group, and a 2,3-epoxypropyl group.

Examples of the acyl group include acetyl group, propionyl group, butyroyl group, acryloyl group,
Methacryloyl group, octanoyl group, benzoyl group and the like can be mentioned. X in the general formula (I) is a general formula:

[0045]

[Chemical 6]

It is a polyvalent acyloxy group represented by: This polyvalent acyloxy group has the general formula:

[0047]

[Chemical 7]

It is derived from the polycarboxylic acid represented by Examples of such polycarboxylic acid include propane-1,2,3-tricarboxylic acid, butane-1,2,3
3,4-tetracarboxylic acid, pentane-1,2,3
4,5-pentacarboxylic acid, hexane-1,2,3,
Examples include 4,5,6-hexacarboxylic acid, propane-1,2,3-tricarboxylic acid, butane-1,2,
3,4-tetracarboxylic acid is preferred. On the other hand, the second preferred hindered amine-based light stabilizer has the general formula:

[0049]

[Chemical 8]

[In the formula, R ₁ and R ₂ are the same or different alkyl groups, 1 is 1, 2 or 3 and R ₃ is 1
When = 1, a monovalent acyl group, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an N-substituted carbamoyl group, or a general formula:

[0051]

[Chemical 9]

(Wherein R ₄ and R ₅ represent the same or different alkyl groups), and when 1 = 2, a diacyl group, a dicarbamoyl group, a dicarbonyl group, a carbonyl group. A group, an alkylene group, an arylene group or an arylenedialkylene group,
= 3 indicates a triacyl group and an alkanetoluyl group. ] It has a structure represented by.

In the general formula (V), R ₁ and R ₂
Are the same or different alkyl groups. For example, it may be a methyl group, an ethyl group, an isopropyl group, a dodecyl group, or the like, and R ₁ and R ₂ may be bonded at a carbon atom to form a ring. R ₃ is a monovalent acyl group, alkyl group, cycloalkyl group, aryl group, aralkyl group or N-substituted carbamoyl group when 1 = 1. Examples of these include an acetyl group, a propionyl group,
Butyryl group, stearoyl group, acryloyl group, benzoyl group, phenoxyacetyl group, cyclohexanoyl group, α-naphthoyl group, ethylcarbamoyl group, n-butylcarbamoyl group, methyl group, ethyl group, n-butyl group, octyl group, Examples thereof include styryl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, benzyl group, phenethyl group, phenyl group, toluyl group and naphthyl group.

When l = 2, R ₁ is a diacyl group, a dicarbamoyl group, a carbonyl group, an alkylene group, an arylene group or an arylenedialkylene group.
Examples of these are carbonyl group, oxalyl group, malonyl group, adipyl group, sebacyl group, fumaryl group, terephthal group, methylene group, ethylene group, propylene group, hexamethylene group, p-phenylene group, p-xylylene group,
Examples thereof include a tolylene-2,4-dicarbamoyl group and a hexamethylene-1,6-dicarbamoyl group.

Further, R ₁ is a triacyl group or an alkanetriyl group when l = 3, and examples thereof include a benzene-1,3,5-tricarbonyl group and benzene-1,3,3.
4-tricarbonyl group, cyclohexane-1,3,5-
Tricarbonyl group, propane-1,2,3-yl group, hexane-1,3,6-yl group and the like can be mentioned. Specific examples of the hindered amine light stabilizer 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 (2,2,2
6,6-Tetramethyl-4-piperidyloxy) -p-
Xylene, bis (2,2,6,6-tetramethyl-4-
Piperidyl) tolylene-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-tricarboxylate, tris (2,2,6,6-tetramethyl-4-piperidyl)-
Examples thereof include benzene-1,3,4-tricarboxylate. Among these, bis (2,2,6,6-tetramethyl-4-piperidyl) -sebacate, bis (2,2,6,6) 6-tetramethyl-4-piperidyl)-
Adipate, 4-benzoyloxy-2,2,6,6-
Tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine and the like are preferable. The above hindered amine light stabilizers may be used alone or in combination of two or more.

The amount of the hindered amine-based stabilizer compounded in the composition of the present invention is 0.01 to 3 parts by weight, preferably 0.05 to 100 parts by weight, based on 100 parts by weight of the polyacetal resin.
It is selected in the range of 1.5 parts by weight. This compounding amount is 0.01
If it is less than part by weight, sufficient weather resistance cannot be obtained. On the other hand, if it exceeds 3 parts by weight, the thermal stability is lowered, silver streaks (silver stripes) are generated due to decomposition gas during molding, and the appearance of the molded product is remarkably deteriorated, which is not preferable.

The composition of the present invention further comprises additives conventionally used in polyacetal resin compositions, for example, heat stabilizers such as polyamide and melamine, and 2,2'-methylene-bis (4-methyl-6-t-). Butylphenol), triethylene glycol-bis [3- (3-t-butyl-5-
Methyl-4-hydroxyphenyl) propionate],
Antioxidants such as pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], antistatic agents such as polyethylene glycol, polypropylene glycol, polyethylene glycol alkyl ethers, lubricants, glass Reinforcing agents such as fiber, carbon fiber, potassium titanate fiber, organic fiber,
If desired, glass beads, talc, a permanent filler such as calcium carbonate, a nucleating agent, a release agent, a plasticizer, carbon black, a pigment, and the like can be added.

The composition of the present invention is obtained by blending the above-mentioned components and further melt-kneading. As the melt kneader, for example, a kneader, a roll mill, a known device that is usually used for kneading a resin melt such as an extruder can be used, but the extruder is most suitable from the viewpoint of blocking oxygen and working environment. is there. Types of this extruder include uniaxial type, biaxial type, vented type, and no vent type, and the composition of the present invention can be prepared by any type of extruder.

Further, the composition of the present invention can be used by blending with polyacetal homopolymers, copolymers, branched polymers and block copolymers which are generally used. The polyacetal resin composition according to the present invention imparts effective matting properties to a molded article having any surface, but a particularly large gloss is obtained for a molded article molded with a textured mold. It has an erasing effect.

Preferred applications of the polyacetal resin composition of the present invention are, for example, levers, instrumental panels, switch parts, handles, clips, housings and the like. Especially suitable for automobile interior parts.

[0061]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In each of the examples and the comparative examples, each characteristic was evaluated with a red-colored product of each composition. The color change due to weather resistance evaluation includes color change due to cracks, color change due to precipitation of decomposed products of additives and polyacetal resin on the surface of molded products, and color change due to deterioration of pigment. This is because it is practically meaningless to evaluate in the above, and comprehensive evaluation is important in practical use.

The properties of the compositions of the examples and comparative examples were determined as follows. Matting performance evaluation (glossiness measurement): A test piece (JIS No. 1 dumbbell) was molded with a 3 ounce molding machine (condition: mold temperature 80 ° C., cooling time 20 seconds). Incidence angle 60 °, reflection angle 60 using a color meter made by Color Industry
Measured in °.

Evaluation of weather resistance: The test piece used for the above-mentioned gloss measurement was measured by a fade meter (WEL- manufactured by Suga Test Instruments Co., Ltd.).
SUN-HC-B-EM type), and exposed under conditions of a black panel temperature of 83 ° C. and a humidity of 50%, and after 1200 hours of exposure, the color difference and the degree of cracking were determined under the following conditions.

(A) Color difference: The light irradiation surface of the test piece was measured by a color difference meter (Handy Color Tester HC-T manufactured by Suga Test Instruments Co., Ltd.).
Was used to determine the ΔE value (JIS Z-8730).
The smaller the value, the smaller the change in color. (B) Degree of cracking: The light-irradiated surface of the test piece was observed with a microscope of 100 times, and the degree was evaluated according to the following criteria.

Criteria: 0: There is no crack. 1: There are slight cracks. 2: The crack is long and clear. 3: Long cracks, 20 or more in one visual field.

4: Cracks are generated all over the surface. The symbols in the table indicate the following. (A) UV absorber : a-1: 2- (2'-hydroxy-3 ', 5'-t-butylphenyl) benzotriazole, a-2: 2- [2'-hydroxy-3', 5 ' -Bis-
(Α, α-Dimethylbenzyl) phenyl] benzotriazole, i-3: 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, i-4: 2-ethoxy-2′-ethyl oxalic acid Bisanilide, i-5: 2-hydroxy-4-methoxybenzophenone (b) hindered amine light stabilizer : b-1: a hindered amine light stabilizer of the general formula (I), wherein Y is a hydrogen atom and m is 2 , N is 1.5-2, which is a hindered amine-based light stabilizer of the general formula (I), Y is a methyl group, m is 2, and n is 1.5-3, and 3 is a hindered amine-based light stabilizer of the general formula (I). A light stabilizer, wherein Y is a methyl group, m is 1, and n is 1.5 ro-4: bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, ro-5: bis (2 , 2,6,6-tetramethyl-4 Piperidyl) adipate, b -6: 4-benzoyloxy-2,2,6,6-tetramethylpiperidine

[0067]

[Reference Example 1] <Production of polyacetal resin> Polyacetal homopolymer powder acetylated at both ends was prepared according to US Pat.
09 known method. The intrinsic viscosity of this product was 1.2. (Intrinsic viscosity is 2% by weight of alpha-pinene in a p-chlorophenol solution containing polymer 0.
1% by weight was melted and measured at 60 ° C.)
The melt index under D1238-57T (condition E) was 9.0 g / 10 minutes. This polyacetal is designated as P-1.

A polyacetal copolymerized with 2.8% ethylene oxide was synthesized by the known method described in US Pat. No. 3,027,352. The intrinsic viscosity of this product was 1.0. The melt index was 20.0 g / 10 minutes. This polyacetal is designated as P-2.

[0069]

[Reference Example 2] <Production of multi-phase interpolymer> In a 10-liter beaker equipped with a stirrer and a condenser, 5.7 liters of distilled water and sodium dioctylsulfosuccinate 2 as an emulsifier
0 g and Rongalit 1.2 g as a reducing agent are added and uniformly dissolved.

As a soft phase of the first phase, a monomer composition shown in the attached table and a uniform solution of 2 g of diisopropylbenzene hydroperoxide (hereinafter abbreviated as PBP) were added and polymerized at 80 ° C. The reaction was completed in about 40 minutes. The polymerization yield at this point was substantially 100%. Next, as the hard phase (outermost phase) of the second phase, the monomer composition and PB shown in the attached table
A uniform solution of 0.6 g of P and 0.2 g of n-octyl mercaptan (hereinafter abbreviated as OM) was added. The reaction at this stage was completed in about 15 minutes.

Then, the temperature was raised to 95 ° C. and kept for 1 hour. The obtained polymer was put into a 0.5% aluminum chloride aqueous solution to coagulate the polymer, washed 15 times with warm water, and dried to obtain a white floc-like multiphase interpolymer. The average particle size of this product was 0.2 μm.

[0072]

Examples 1 to 12 and Comparative Examples 1 to 12 <Production of Polyacetal Resin Composition> The above-described polyacetal and multiphase interpolymer were blended at a blending ratio shown in Tables 1 to 6 in a nitrogen atmosphere and heated to 200 ° C. The pellets obtained by melt-kneading with a twin-screw vent extruder (condition: screw rotation speed; 100 rpm, discharge 3 kg / hr) of L / D = 25 that was set were dried. Next, this pellet 1
0.2 parts by weight of a pigment (quinacridone red pigment), 0.2 parts by weight of each of the UV absorbers and hindered amine light stabilizers shown in Tables 1 to 6 were added to 00 parts by weight and blended, and a uniaxial extruder was used. Were melt-mixed again with, and the obtained colored pellets were dried and used for each evaluation.

<Evaluation of Composition> A test piece was prepared from the obtained colored pellets under the above-mentioned conditions, and each item was evaluated. The results are shown in Tables 1-6. The abbreviations in the table are as follows. BA: butyl acrylate EGA: ethylene glycol diacrylate ALMA: allyl methacrylate MMA: methyl methacrylate GMA: glycidyl methacrylate 2EHA: 2-ethylhexyl acrylate BD: butadiene ST: styrene

[0074]

[Table 1]

[0075]

[Table 2]

[0076]

[Table 3]

[0077]

[Table 4]

[0078]

[Table 5]

[0079]

[Table 6]

[0080]

According to the present invention, it is possible to obtain a polyacetal resin composition which is excellent in both matting properties and weather resistance.

Claims (1)

[Claims] 1. 1 to 100 parts by weight of a multiphase interpolymer having a multiphase structure of two or more phases composed of repeating soft phases and hard phases from the central phase to the outermost phase with respect to 100 parts by weight of a polyacetal resin 1 to 100 parts by weight benzotriazole type And 0.01 to 5 parts by weight of at least one UV absorber selected from anilide oxalates, and 0.01 to 5 parts by weight of a hindered amine light stabilizer.