JP3187917B2 - 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 a reduced surface gloss. More specifically, a polyacetal resin composition with a specific core-shell polymer and an inorganic filler added to and mixed with a polyacetal resin, while maintaining the inherent mechanical properties and moldability of polyacetal while significantly reducing the gloss of the molded product surface And a molded product thereof.

[0002]

2. Description of the Related Art As is well known, polyacetal resins have excellent mechanical properties, physical properties such as electrical properties, or chemical properties such as chemical resistance and heat resistance. In recent years, it has been used in a very wide field as a resin. However, with the expansion of fields in which polyacetal resins are used, there may be cases where the properties of the materials are required to be more specific. One of these properties is the interior and exterior of automobiles,
In the field of optical machines and the like, for the purpose of suppressing irritation to the eyes due to light reflection, preventing malfunction of equipment, and further giving a sense of quality, a material having low gloss, that is, low light reflection is required. There are cases. In addition, in the fields of general electric equipment and building materials, the use of various materials in combination is increasing according to the purpose, but polyacetal resin has better surface gloss than other general resin materials. Therefore, products incorporating various materials have a poor sense of harmony with other materials, and their use in fields that emphasize surface appearance has been somewhat limited. Furthermore,
Since these materials go outside, it is necessary to maintain excellent weather resistance. In order to meet this demand and reduce the surface gloss, a method of adding an inorganic filler such as calcium carbonate or talc to a polyacetal resin has been conventionally known. However, in order to obtain the desired gloss reduction effect by these methods, it is necessary to incorporate a large amount of talc or the like, and as a result, other mechanical properties, particularly, elongation and toughness are reduced, and post-processing of the molded product is performed. It has the disadvantage that it is easily broken when subjected to stresses such as stress during assembly or dropping during the handling of a molded product, or whitening of the resin due to reduced weather resistance. Therefore, it has been desired to develop a polyacetal resin material having excellent mechanical properties such as elongation and toughness, and having excellent weather resistance and sufficiently suppressed surface gloss.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have developed a polyacetal resin in which the gloss of the surface of a molded article is extremely suppressed without sacrificing as much as possible the excellent characteristics inherent in the polyacetal resin. As a result of intensive studies, the present invention has been completed. That is, the present invention relates to (A) 100 to 100 parts by weight of a polyacetal resin, 0.5 to 100 parts by weight of a core-shell polymer having (B) a glassy polymer shell comprising a rubbery polymer core and a vinyl copolymer having an oxygen-containing polar group. and with (C) average grain structure of grain size 0.5 ～50Myuemu, calcium carbonate, a Ruminokei salt, polyacetal resin composition obtained by blending an inorganic filler from 0.5 to 30 parts by weight selected from talc and to a molded article Things. Further, the present invention relates to a polyacetal resin composition comprising, as required, 0.01 to 5 parts by weight of (D) a weather (light) -resistant stabilizer in addition to the above basic components.

Hereinafter, the components of the present invention will be described in detail. The (A) polyacetal resin used in the present invention is a polymer compound having an oxymethylene group (—CH ₂ O—) as a main constituent unit, and contains a small amount of other constituent units in addition to the polyoxymethylene homopolymer and the oxymethylene group. May be any of copolymers, terpolymers, and block copolymers, and may have not only a linear molecule but also a branched or crosslinked structure. There are no particular restrictions on the degree of polymerization or the like.

Next, the core-shell polymer (B) used in the present invention has a rubber-like polymer core and a glass-like polymer shell composed of a vinyl copolymer having an oxygen-containing polar group. Of these, it is usually obtained by a continuous multi-stage emulsion polymerization method in which the polymer of the previous stage is sequentially coated with the polymer of the subsequent stage. At the time of particle-generating polymerization, it is preferable to start the emulsion polymerization reaction by adding a monomer, a surfactant, and water to a reactor, and then adding a polymerization initiator. The first stage of polymerization is a reaction that forms a rubbery polymer. Examples of the monomer constituting the rubbery polymer include a conjugated diene, an alkyl acrylate having an alkyl group having 2 to 8 carbon atoms, and a mixture thereof. These monomers are polymerized to form a rubbery polymer. Such conjugated dienes include, for example, butadiene, isoprene,
Chloroprene and the like can be mentioned, but butadiene is particularly preferably used. Further, when the alkyl group has 2 carbon atoms.
Examples of the alkyl acrylate of No. 8 to 8 include ethyl acrylate, propyl acrylate, butyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate, and butyl acrylate is particularly preferably used. In the first stage of polymerization, monomers copolymerizable with conjugated dienes and alkyl acrylates, for example, styrene, vinyl toluene, α
-An aromatic vinyl such as methylstyrene, an aromatic vinylidene, vinyl cyanide such as acrylonitrile and methacrylonitrile, and vinyl methacrylate, an alkyl methacrylate such as methyl methacrylate and butyl methacrylate can be copolymerized.

Examples of the crosslinkable monomer include aromatic divinyl monomers such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate, oligoethylene glycol diacrylate, and oligoethylene glycol diacrylate. Ethylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate and the like alkane polyol polyacrylate or alkane polyol polymethacrylate, etc.
Particularly, butylene glycol diacrylate and hexanediol diacrylate are preferably used. Examples of the grafting monomer include allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, and allyl unsaturated carboxylic acid esters such as diallyl itaconate. Particularly, allyl methacrylate is preferably used. Such a crosslinking monomer and a grafting monomer are used in an amount of 0 to 5% by weight, preferably 0.1 to 2% by weight, based on the total amount of the first-stage monomers.

In the shell phase, a glassy polymer comprising a vinyl copolymer having an oxygen-containing polar group is formed.
As the oxygen-containing polar group in the present invention, for example, a hydroxyl group,
Groups having an ether bond (-O-) (such as glycidyl group), an amide group (-CONH) and nitro group (-NO ₂₎ Although the like, a group especially having a hydroxyl group and an ether bond preferably.

[0008] In a core-shell polymer having no oxygen-containing polar group in the shell phase, a matting effect (gloss-reducing effect) is hardly recognized, and the core-shell structure of the present invention is taken even if it has an oxygen-containing polar group. For vinyl polymer particles which are not used, a slight effect is recognized but not sufficient. As a monomer constituting the vinyl copolymer having an oxygen-containing polar group, for example, a (meth) acrylate of an alcohol having two or more oxygen-containing polar groups in a molecule is used. Here, the alcohol having two or more oxygen-containing polar groups in the molecule refers to an alcohol having at least one oxygen-containing polar group in addition to the hydroxyl group in the alcohol part. Examples of the (meth) acrylate of an alcohol having an oxygen-containing polar group include (meth) acrylate of an alcohol having a hydroxyl group and / or a glycidyl group. As the (meth) acrylate of the alcohol having a hydroxyl group, for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and the like can be mentioned, but hydroxyethyl methacrylate is preferably used. Examples of the (meth) acrylate of the alcohol having a glycidyl group include glycidyl (meth) acrylate.
Preferably, glycidyl methacrylate is used. Further, a vinyl monomer having an oxygen-containing polar group such as allyloxyethanol and allyl glycidyl ether other than the above (meth) acrylate can also be used as a component of the vinyl copolymer having an oxygen-containing polar group. . Examples of the monomer constituting the glassy polymer other than the monomer having an oxygen-containing polar group include methyl (meth)
Alkyl (meth) acrylates such as acrylate, ethyl (meth) acrylate and butyl (meth) acrylate; aromatic vinyls such as styrene, vinyltoluene and α-methylstyrene; vinyl cyanide such as aromatic vinylidene, acrylonitrile and methacrylonitrile. And vinyl polymerizable monomers such as vinylidene cyanide. Particularly preferred are methyl methacrylate, styrene-acrylonitrile and the like. Further, an intermediate phase may be present between the first stage and the final polymerization phase. For example, a polymerizable monomer having a functional group such as glycidyl methacrylate, methacrylic acid, hydroxyethyl methacrylate, a polymerizable monomer forming a glassy polymer such as methyl methacrylate, a polymerizable monomer forming a rubbery polymer such as butyl acrylate, etc. Is subjected to seed emulsion polymerization to form an intermediate phase. Such an intermediate phase can be selected variously depending on the properties of the desired core-shell polymer. The structure of the core-shell polymer having such an intermediate phase is, for example, a multilayer structure in which another layer is present between the core and the shell, or a dispersion in which the intermediate phase becomes fine particles in the core. One that has a salami structure is used. In a more extreme case of a core-shell polymer having a salami structure, the mesophase to be dispersed may form a new core at the center of the core. The core-shell polymer having such a structure may occur when a monomer represented by styrene is used as a monomer constituting the intermediate phase. In addition, when a core-shell polymer having a mesophase is used, the impact resistance is improved, the flexural modulus is improved, the heat distortion temperature is increased, and the appearance (suppression of surface peeling and pearl luster, color change due to refractive index change) is improved. May be improved.

In the emulsion polymerization of the present invention, surfactants such as nonionic surfactants, oligomeric anionic or oligomeric nonionic surfactants, and azo polymerization initiators and peroxide polymerization initiators are used. Of the polymerization initiator. As the nonionic surfactant used in the present invention, polyoxyethylene nonyl phenyl ether,
Polyoxyethylene stearyl ether, ether type such as polyoxyethylene lauryl ether, ester type such as polyoxyethylene monostearate, sorbitan ester type such as polyoxyethylene sorbitan monolaurate, polyoxyethylene polyoxypropylene block copolymer, etc. Most widely used nonionic surfactants such as block polymer type surfactants can be used. The oligomer-type anionic or oligomer-type nonionic surfactant used in the present invention is an oligomer-type surfactant conventionally used in an emulsion polymer for a special purpose, for example, an oligomer-type surfactant of the following formula: Is used.

[0010]

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The oligomer type surfactant is already water-soluble, or is converted into a water-soluble salt by reacting with an oxide, hydroxide or alcohol. Examples of the water-soluble salt include alkali metal salts, alkaline earth metal salts,
Examples include Group I heavy metal salts, ammonium salts, substituted ammonium salts, and the like, with ammonium salts being particularly preferred. The oligomer type surfactant is, for example, as described in JP-B-47-34832, addition polymerization of a suitable monomer in a water-free solvent in the presence of an alkyl mercaptan, or It is then obtained by oxidation with hydrogen peroxide or ozone to the corresponding sulphoxide or sulphone. Examples of the alkyl mercaptan include alkyl mercaptans such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and n-decyl mercaptan. Examples of the monomer include (meth) acrylic acid, α-ethylacrylic acid, β-methylacrylic acid, α, β-dimethylacrylic acid, caproic acid, itaconic acid, fumaric acid,
Maleic acid, (meth) acrylamide, vinyl ethyl ether, vinyl methyl ether, allyl alcohol, vinyl pyrrolidone, (meth) acrylonitrile, ethyl acrylonitrile, methyl (meth) acrylate, ethyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) A) having at least one polar group in a molecule such as acrylate, vinyl acetate, vinyl propionate, N-isopropylacrylamide, N-ethylacrylamide, N-methylacrylamide, glycidyl (meth) acrylate, and N-methylolacrylamide; , Β-ethylenically unsaturated monomers are used. As the solvent used in the addition polymerization, for example, lower alkanols such as methanol, ethanol, and isopropanol are preferable. Usually, the above addition polymerization is performed at 20 to 100 ° C.
It is performed in the range of about In the present invention, the addition amount of the surfactant is appropriately selected depending on the particle stabilizing ability of the surfactant. As the polymerization initiator, azobisisobutyronitrile, dimethyl 2,2'-azobisisobutyrate, 2,2'-azobis (2-amidinium Nopuropan) azo-based polymerization initiators such as dihydrochloride, cumene hydroperoxide And peroxide polymerization initiators such as diisopropylbenzene hydroperoxide and hydrogen peroxide are used alone or in combination of two or more. The nonionic surfactant and / or
Alternatively, if emulsion polymerization is carried out in a reaction system using an oligomer type surfactant and an azo-based and / or peroxide-based polymerization initiator, a sulfur-oxidized compound (eg, sulfate, sulfate ester, peroxide, etc.) (Sulfate, sulfite, sulfonate, etc.), or a very small amount of a core-shell polymer. The addition amount of the core-shell polymer of the present invention to 100 parts by weight of the polyacetal resin is 0.
The amount is 5 to 100 parts by weight, preferably 1 to 50 parts by weight, more preferably 1 to 30 parts by weight. If the addition amount of the core-shell polymer is too small, the effect of lowering the surface gloss is not sufficiently exhibited, and even if added unnecessarily, a large decrease in mechanical properties, particularly rigidity, is observed, and it is not preferable for heat stability. Affects.

By adding and blending the core-shell polymer (B) into the polyacetal resin (A), the gloss of the surface of the obtained molded article is uniformly reduced, and a calm and high-grade feeling is obtained. Retains excellent mechanical properties. Such a gloss reduction effect is due to the fact that the core-shell polymer (B) is present on the surface of the molded product obtained by adding and blending the core-shell polymer in the polyacetal resin.
Oxygen-containing polar groups are uniformly dispersed on the surface at the same time that the surface of the polyacetal resin is roughened while dispersing in the form of particles of about 0.5 to 2 μm, and the surface of the polyacetal resin molded product is modified to maintain the surface smoothness to some extent. It is considered that the gloss becomes low while the color is low.

Further, the composition of the present invention can be used as it is ((A) +
The component (B) also has an effect on lowering the gloss of the surface of the molded article when used in combination with the component (A) to the component (B). Further effects can be obtained. Here, the inorganic filler of the component (C) has a granular structure having an average particle diameter of 0.5 to 50 μm, and preferably has an average particle diameter of 2 to 30 μm. Although not particularly limited for the type, in consideration of the efficiency or the physical properties such as for gloss reduction is an object of the present invention, calcium carbonate, A Ruminokei salt, Ru talc is preferably used.

The amount of the inorganic filler used in the present invention is 0.5 to 30 per 100 parts by weight of the polyacetal resin.
Parts by weight, preferably 1 to 20 parts by weight. If the amount is less than this, the synergistic effect of lowering the gloss of the molded product surface is small,
If the amount is too large, the uniformity of the surface of the molded product is reduced, and unevenness is generated, and at the same time, the physical properties (particularly, elongation and toughness) are adversely affected.

The degree of surface gloss is practically preferably 20% or less, more preferably 15% or less, and particularly preferably 10% or less, as measured by the measurement method described below (using a mirror mold). Also, with the recent sophistication of the interior of automobile interiors, and in order to improve the feel, most of the interior parts have been subjected to a grain finish called leather grain and satin grain to reduce the gloss on the mirror surface. At the same time, high transferability to the textured surface is required. Ordinary polyacetal resin is poor in transferability, probably because of high crystallinity, and the rate of decrease is smaller than the decrease in gloss on a mirror surface. In the composition of the present invention, by modifying the surface of the polyacetal resin molded product, not only the gloss on the mirror surface is reduced, but also the transferability to the textured surface is extremely improved, and the gloss on the textured surface is improved. Is even lower. As the molded article of the present invention, a molded article whose surface is formed into an embossed shape by using an injection molding machine equipped with an injection molding die in which the inner surface of the resin composition is embossed is preferable. Further, the molded article having a grain shape includes a molded article in which part or all of the surface of the molded article has a grain shape. Therefore, the inner surface of the mold used at that time only needs to be partially or entirely grained according to the purpose. The graining of the inner surface of these molds can be performed by a corrosion process such as chemical etching, electric discharge machining, or the like, and the surface roughness of the grain pattern can be selected according to the appearance of a target molded product.

By using (A) the polyacetal resin of the present invention in combination with (B) a specific core-shell polymer and (C) an inorganic filler, the polyacetal resin can be used in comparison with the case of using the component (B) alone or the component (C) alone. It is possible to remarkably reduce the gloss of the surface of the molded article with a very small amount, and to maintain the balanced mechanical properties of the polyacetal. Such a gloss reduction effect is caused by a synergistic effect of the components (B) and (C). In other words, in the molded article obtained by adding and blending the core-shell polymer and the inorganic filler into the polyacetal, the core-shell polymer (B) is dispersed in the surface to a particle size of about 0.5 to 2 μm to modify the molding surface, and (C) It is considered that the inorganic filler is dispersed on the surface and the surface of the polyacetal is roughened, thereby reducing the gloss. The component (B) alone has a small effect of roughening the surface, and the component (C) alone requires a large amount of compounding in order to obtain a desired reduction in gloss, and has the disadvantage of deteriorating mechanical properties and the like. I have.

Although the present invention shows excellent effects as it is, by adding (D) a weathering (light) stabilizer to the components (A) to (C), very excellent weathering (light) resistance can be obtained. It becomes a composition having. Among the (D) weather (light) -resistant stabilizers used herein, those preferably used are benzotriazole-based substances, benzophenone-based substances, oxalic anilide-based substances, aromatic benzoate-based substances, cyanoacrylate-based substances, and hindered amines. One or more selected from the group consisting of system substances. The following are examples of these substances.

That is, as the benzotriazole-based substance, 2- (2'-hydroxy-5'-methyl-phenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butyl- Phenyl) benzotriazole, 2-
(3,5-di-t-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-isoamyl-phenyl) benzotriazole, 2-
Benzophenone-based substances such as [2-hydroxy-3,5-bis- (α, α-dimethylbenzyl) phenyl] benzotriazole and 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole include , 4-Dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2 Examples of oxalic anilide-based substances such as'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, and 2-hydroxy-4-oxybenzylbenzophenone include N- (2-ethyl- Phenyl) -N '-(2-ethoxy-5-t-butylphenyl) oxalic acid Amide, N-(2-ethyl-- phenyl) -N '
-(2-ethoxy-phenyl) oxalic acid diamide and the like aromatic benzoate-based substances such as pt-butylphenyl salicylate and p-octylphenyl salicylate; and cyanoacrylate-based substances such as 2-ethylhexyl-2-cyano- Hindered amine-based substances such as 3,3-diphenyl acrylate and ethyl-2-cyano-3,3-diphenyl acrylate are piperidine derivatives having a sterically hindered group, and examples thereof include 4-acetoxy-2,2. , 6,6-tetramethylpiperidine, 4-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,
2,6,6-tetramethyl-4-piperidyl) terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ethane, bis (2,2,6,6-tetra) Methyl-
4-piperidyl) hexamethylene-1,6-zircabamate, bis (1-methyl-2,2,6,6-tetramethyl-4-
Piperidyl) adipate, tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate and the like. Also effective are polycondensates of high molecular weight piperidine derivatives, for example, polycondensates of dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate. At least one or two of these weather (light) stabilizers are used.
It is preferable to mix more than one kind, and it is particularly preferable to use a combination of the above-mentioned weather-resistant stabilizer and a hindered amine-based substance,
Further, a combination of a benzotriazole-based substance and a hindered amine-based substance is most preferable. The weathering (light) stabilizer (D) used here is 0.01 to 100 parts by weight of the component (A).
The amount is suitably from 5 to 5 parts by weight, and particularly preferably from 0.02 to 3 parts by weight. If these ingredients are too small, the effect cannot be expected,
Also, even if it is added excessively unnecessarily, it is not only economically disadvantageous,
This results in problems such as deterioration of mechanical properties and contamination of the mold.

In the composition of the present invention, it is preferable to add a coloring component such as a dye or a pigment described below.
There are no particular restrictions on the types of dyes and pigments to be used, and any type may be selected from those conventionally used in polyacetal compositions. As the dye, for example, anthraquinone-based dyes and the like are preferable, and as the pigment, carbon black, azo-based, phthalocyanine-based, perylene-based, quinacridone-based, anthraquinone-based, indoline-based, titanium-based, iron oxide-based, cobalt-based, and the like are preferable. . These coloring components may be used alone or in combination of two or more. In particular, when carbon black is added as a coloring component, there is an effect of further improving the weather resistance stability. As the carbon black, those usually used for coloring plastics, for example, Micronex, acetylene black, Ketjen black and the like can be used. In the composition of the present invention, the amount of the coloring component is preferably in the range of 0.1 to 10 parts by weight per 100 parts by weight of the polyacetal resin. In particular, 0.3 to 5 parts by weight is suitable. If the amount is less than 0.1 part by weight, the coloring effect is not sufficiently exhibited, and it is not necessary to add the amount of coloring more than 10 parts by weight.If the amount is too large, the physical properties and thermal stability of the composition are rather reduced. Lower.

The composition of the present invention is preferably further added with various known stabilizers to reinforce the heat stabilizer. For this purpose, known antioxidants, nitrogen-containing compounds, alkali or alkaline earth metal compounds are used. It is desirable to use one or more of these. In order to further impart desired characteristics to the composition of the present invention, conventionally known additives such as a lubricant, a nucleating agent, a release agent, an antistatic agent and other surfactants, or components other than the component (B) It is possible to add and contain one or two or more kinds of organic polymer materials or inorganic fillers other than the component (C).

The composition of the present invention can be prepared by equipment and a method generally known as a method for preparing a synthetic resin composition. That is, necessary components are mixed, kneaded using a single-screw or twin-screw extruder, and extruded to form pellets for molding. The composition can be adjusted by molding with a molding machine. It is also possible to do it at the same time. Further, in order to improve the dispersion and mixing of the components, a method in which a part or all of the resin component is pulverized, mixed, and molded into a melt-extruded pellet may be used. The compounds such as the stabilizers and additives may be added at any arbitrary stage, and may be added or mixed immediately before obtaining a final molded article. Further, the resin composition according to the present invention is extrusion molding, injection molding,
It can be formed by any of compression molding, vacuum molding, blow molding and foam molding.

[0022]

The present invention will be described below with reference to examples.
The present invention is not limited to these. In the Examples and Comparative Examples, all “parts” represent parts by weight. The methods used for evaluating the surface state and the characteristic values of the mechanical properties in the examples are as follows. (1) Measurement of surface condition and surface glossiness The surface condition and surface glossiness were measured using a test piece (70 mm × 40 mm × 3 mm thick) molded under the following conditions using a mirror and a mold with a grain. . (A) Surface The surface condition is 1
The matte state and the uniformity of the molding surface were evaluated. The smaller the number, the better the uniformity and the better the matte state. 1: The surface is uniform and the matte state is good. 2: The surface gloss is reduced, but the surface irregularities are uneven and rough. 3: The surface gloss is uneven and mottled in the unerased and unerased parts. 4: The gloss of the surface is hardly reduced. Alternatively, the mottled pattern on the surface is large, and the portion where gloss is not reduced is large. (B) The surface gloss was measured in accordance with the JIS K7105 gloss measurement using a digital variable-angle gloss meter (UGV-4 manufactured by Suga Test Instruments Co., Ltd.).
At 0), the glossiness at 45 ° -45 ° reflection was measured. * Molding machine: IS80 manufactured by Toshiba Corporation * Molding conditions Nozzle C1 C2 C3 Cylinder temperature (° C) 200 190 180 160 Injection pressure 650 (kg / cm ² ) Injection speed 1.0 (m / min) Mold temperature 80 (° C) (2) Weather resistance test Ultraviolet fade meter (FAL-AU ・ H manufactured by Suga Test Instruments Co., Ltd.)
· B · Em type), and ultraviolet rays were irradiated at a black panel temperature of 83 ° C to evaluate the crack generation time and changes in the surface state. Crack generation time The test piece was irradiated with ultraviolet rays under predetermined conditions, and the presence or absence of cracks on the test piece surface was observed with a 10-fold loupe to determine the crack generation time for the first time. The higher the value, the better. Changes in surface condition The test piece is exposed to ultraviolet light for a certain period of time (600 hours, 10 hours).
(00 hours) Irradiation, changes in the hue of the test piece before and after irradiation, and the state of cracks are observed, and the degree of those changes is displayed in five stages. The smaller the number, the smaller the change, that is, the less discoloration and occurrence of cracks. (3) Tensile test Tensile strength and elongation were measured in accordance with ASTM D638. (4) Izod impact value Izod impact value was measured according to ASTM D256.

Abbreviations used in Examples and Comparative Examples are as follows. Ethyl acrylate EA Methyl methacrylate MMA Butyl acrylate BA 1,4-butylene glycol acrylate BGA Allyl methacrylate AlMA Methacrylamide MAM Nonionic surfactant (Emulgen 950 manufactured by Kao) E950 Oligomer type anionic surfactant Surfactant A It was synthesized according to the description of JP-A-53-10682 and Example 13, adjusted to pH 7.5 with aqueous ammonia, and adjusted to a solid content of 10% with pure water.

[0024]

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(Where a: b = 7: 3, a + b = about 13.6) <Composition> Methacrylic acid 155 g MMA 360 g n-Dodecylmercaptan 109 g Azobisisobutyronitrile 4.4 g Isopropanol 314 g Molecular weight 1310 Deionized water DIW 2,2'-azobis (2-amidinium Nopuropan) dihydrochloride V50 (Wako pure Chemical (manufactured) V50) of 2-hydroxyethyl methacrylate HEMA styrene St glycidyl methacrylate GMA production example 1-3 <core-shell polymer B-. 1 to Production of 3> In a polymerization vessel equipped with a 5-liter reflux condenser, DIW 1200 g, 25%
1.68 g of aqueous ammonia, 7 g of surfactant A, and 0.14 g of MAM were charged and heated to 70 ° C. while stirring under a nitrogen stream. After adding 27.86 g of a seed monomer mixture having the following composition and dispersing it for 10 minutes, 21 g of a 10% aqueous solution of V50 was added.
Was added to polymerize the seed particles. Subsequently, 7 g of MAM was added, and 210 g of surfactant A, 900 g of DIW, and 25 g of DIW were added to 1365 g of the core monomer mixture having the following composition.
And 2.80 g of a 10% V50 aqueous solution 21.0 g of 1% ammonia water 0.63 g
Was continuously fed over 180 minutes to perform seed polymerization. After the temperature was raised to 80 ° C and aged for 1 hour, it was cooled to 70 ° C.

Next, 9 g of a 10% aqueous solution of V50 and 0.27 g of 1% aqueous ammonia were added, and 12 g of a 10% aqueous solution of the shell monomer having the following composition and 10% aqueous solution of V50 were added to 60 g of 60%. Feeding was continued over a period of minutes to perform seed polymerization. Shell part monomer emulsion MMA 265.8 g EA 60.0 g Surfactant A 30.0 g DIW 500.0 g 25% ammonium water 0.72 g St 180.0 g HEMA 90.0 g BGA 1.2 g MAM 3.0 g After heating to 80 ° C and aging for 1 hour, After cooling, the mixture was filtered through a 300-mesh stainless steel wire mesh to obtain a core-shell polymer latex. This latex is frozen at −15 ° C.,
Melt to room temperature and filter through a glass filter, then
Blow dry at 60 ° C for 24 hours.
1 was obtained. The polymerization was carried out in the same manner as in Production Example 1 except that the monomers having the compositions shown in Table 1 were used, and core-shell polymers B-2 and B-3 were obtained.

[0027]

[Table 1]

Example 1 Polyacetal resin (A) (Polyplastics Co., Ltd.)
And Duracon (trade name) were mixed with the core-shell polymer (B-1) and the inorganic filler (C-1) produced as described above in the composition shown in Table 2, and mixed using a Henschel mixer. The mixture was melt-kneaded using a screw extruder to prepare a pellet-shaped composition. Next, a test piece was molded from the pellet under the aforementioned molding conditions using an injection molding machine.
Gloss and other properties were measured and evaluated. Table 2 shows the results. Comparative Example 1 Example 1 was repeated except that the polyacetal resin was not blended with the core-shell polymer and the inorganic filler.
In the same manner as in the above, a polyacetal composition was obtained. Similarly, test pieces were prepared from this composition and evaluated. Table 3 shows the results. Examples 2 to 15 The core-shell polymer (B-1) produced as described above
To B-3) and inorganic fillers (C-1 to C-3), and the composition shown in Table 2 was used to obtain a polyacetal composition in the same manner as in Example 1. Similarly, each test piece was prepared from this composition and evaluated. Table 2 shows the results. Comparative Examples 2 to 13 As shown in Table 3, a composition was prepared, a test piece was prepared and evaluated in the same manner as in Example 1 for a polyacetal resin obtained by adding a core-shell polymer alone or an inorganic filler alone. . Table 3 shows the results. Comparative Examples 14 to 17 As shown in Table 3, the acrylic resin in a non-grafted state was added instead of the component (B), or a system in which the acrylic resin and an inorganic filler were used in combination, or the average particle diameter was A composition was prepared in the same manner as in Example 1 except that an inorganic filler exceeding 50 μm was added to the core-shell polymer, and a test piece was prepared and evaluated. Table 3 shows the results. Examples 16 to 19 A core-shell polymer, an inorganic filler, and a weather (light) stabilizer (D-1 to D-3) were mixed with a polyacetal resin in the composition shown in Table 4, and the polyacetal composition was prepared in the same manner as in Example 1. , And similarly, each test piece was prepared from this composition and evaluated. Table 4 shows the results. Comparative Examples 18 to 22 As shown in Table 5, the same as in Example 1 except that a polyacetal resin alone, a core-shell polymer or an inorganic filler was added, and a weather (light) stabilizer was added in combination. The composition was prepared, test pieces were prepared and evaluated. Table 5 shows the results.

[0029]

[Table 2]

[0030]

[Table 3]

[0031]

[Table 4]

[0032]

[Table 5]

Note-2) C-1: Talc (Crown Talc PP (Matsumura Sangyo)
C ) : Talc (Crown Talc DR (Matsumura Sangyo)
C ) : calcium carbonate (Whiteton P30 (Shiraishi Kogyo)
Ltd.)), an average particle size of about 5 [mu] m C-4: Aluminosilicate (Translink 445 (En
gelhald Corporation)), average particle size about 2.5 μm C ′ -1: calcium carbonate average particle size about 60 μm Note-3) D-1: 2- [2-hydroxy-3,5-bis (α, α-
Dimethylbenzyl) phenyl] benzotriazole D-2: 2-hydroxy-4-oxybenzylbenzophenone Note-4) D-3: Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate Note-5) Acrylic resin B'-1: P (MMA-HEMA) Random copolymer of methyl methacrylate and hydroxyethyl methacrylate (MMA / HEMA; 8/2 (wt%)) B'-2: P (MMA-GMA) methyl methacrylate Copolymer of glycidyl and glycidyl methyl methacrylate (MMA / GMA; 8/2 (Wt%))

[0034]

As is clear from the above description and Examples, the composition of the present invention obtained by adding a specific core-shell polymer and an inorganic filler to a polyacetal resin and blending the polyacetal resin with a mechanically balanced polyacetal resin. A remarkable effect of significantly lowering the gloss of the molding surface while maintaining the physical properties was exhibited. By using a weather (light) stabilizer in combination with the above components, a composition having excellent weather (light) resistance can be obtained. Therefore, the polyacetal resin composition having a low gloss of the present invention has a high-grade appearance, and it is difficult to reflect light.
Interior clips, ventilator knobs, etc.), and outer handles of automobiles, key tops of keyboards, optical machines, housings, household goods, and other applications.

Claims (11)

(57) [Claims] 1. A core-shell polymer having (A) 100 parts by weight of a polyacetal resin and (B) a glassy polymer shell comprising a rubbery polymer core and a vinyl copolymer having an oxygen-containing polar group in an amount of 0.5 to 100 parts by weight. and (C) having a grain structure having an average particle diameter of 0.5 ～50Myuemu, calcium carbonate, a Ruminokei salt, polyacetal resin composition obtained by blending an inorganic filler from 0.5 to 30 parts by weight selected from talc. (B) One component of the vinyl copolymer having an oxygen-containing polar group of the core-shell polymer is (meth) an alcohol having two or more oxygen-containing polar groups in the molecule.
The polyacetal resin composition according to claim 1, which is an acrylate. 3. The (B) core-shell polymer wherein the oxygen-containing polar group is a hydroxyl group and / or a glycidyl group.
Or the polyacetal resin composition according to 2. 4. The polyacetal resin composition according to claim 2, wherein (B) the (meth) acrylate of the core-shell polymer is hydroxyethyl methacrylate or glycidyl methacrylate. 5. The polyacetal resin composition according to claim 1, wherein the core-shell polymer (B) is obtained by emulsion polymerization using an oligomer type surfactant. object. 6. The polyacetal resin composition according to claim 1, wherein the core-shell polymer (B) is obtained by emulsion polymerization using a nonionic surfactant. object. 7. The composition according to claim 1, further comprising (D) weather resistance
A polyacetal resin composition obtained by adding and mixing 0.01 to 5 parts by weight of a (light) stabilizer . 8. The method according to claim 1, wherein (D) the weather (light) -resistant stabilizer is benzotriazo.
-Based substances, benzophenone-based substances, oxalic anilide-based substances
Quality, aromatic benzoate, cyanoacrylate
Selected from the group consisting of substances and hindered amines
The polyacetal resin composition according to claim 7, which is one or more selected from the group consisting of: 9. The (D) weather (light) resistant stabilizer is benzotriazo.
-Based substances, benzophenone-based substances, oxalic anilide-based substances
Quality, aromatic benzoate, cyanoacrylate
One or more of the substances and a hindered amine-based substance
The polyacetal resin composition according to claim 7, which is used in combination . 10. The composition according to claim 1, wherein
Polyacetal resin molded product obtained by molding a product. 11. The molded article according to claim 10 is the one described in the text.
The surface glossiness measured by the method (using a mirror mold) is 20% or less.
A polyacetal resin molded product shown below.