CA2046469A1 - Low gloss polyacetal resin composition and molded article - Google Patents
Low gloss polyacetal resin composition and molded articleInfo
- Publication number
- CA2046469A1 CA2046469A1 CA002046469A CA2046469A CA2046469A1 CA 2046469 A1 CA2046469 A1 CA 2046469A1 CA 002046469 A CA002046469 A CA 002046469A CA 2046469 A CA2046469 A CA 2046469A CA 2046469 A1 CA2046469 A1 CA 2046469A1
- Authority
- CA
- Canada
- Prior art keywords
- polyacetal resin
- resin composition
- gloss
- low
- acrylic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L59/00—Compositions of polyacetals; Compositions of derivatives of polyacetals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/10—Block- or graft-copolymers containing polysiloxane sequences
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Abstract A low gloss polyacetal resin composition comprises:
(A) 100 parts by weight of a polyacetal resin and (B) 0.1 to 40 parts by weight of a silicone graft copolymer prepared by the radical copolymerization of (a) an acrylic-modified silicone with (b) a radical-polymerizable monomer.
It has a lowered surface gloss and provides a molded article having a spcial surface appearance.
(A) 100 parts by weight of a polyacetal resin and (B) 0.1 to 40 parts by weight of a silicone graft copolymer prepared by the radical copolymerization of (a) an acrylic-modified silicone with (b) a radical-polymerizable monomer.
It has a lowered surface gloss and provides a molded article having a spcial surface appearance.
Description
LO~-GLOSS POLYACETAL RESIN COMPOSITION AND MOLDED
ARTICLE
[Field of Industrial Application]
The present invention relates to a polyacetal resin composition which is lowered in surface gloss and exhibits excellent weathering ~light) resistance.
More particularly, the present invention pxovides a polyacetal resin composition which comprises a polyacetal resin, a specific silicone yraft copolymer and, if necessary, a weathering (light) stabilizer and which is lowered in surface gloss and improved in weathering resistance without impairing the well-balanced mechanical properties inherent in a polyacetal resin, and a molded article thereof.
[Prior Art As well known, a polyacetal rewin has recently been used in various fields as an engineering plastic excellent both in physical characteristics such as mechanical and electrical properties and in chemical characteristics such as resistance~ to chemicals and heat. As the field of use of a pol~acetal resin has been enlaxged, however, the resin has been frequently required to exhibit more special properties as materials.
One of such properties is low glossiness, i.e., low light reflectivity, which is requixed in the fields of automotive trim parts and optical ;~ 2~4~
instruments for the purpose of reducing the irritations to the eye due to the reflection of light, inhibiting the malfunction of devices and imparting a high-grade appearance. Meanwhile chances of using two or more materials combined depending upon the object have also increased in the fields of electrical appliances and building materials. In such cases, a polyacetal resin exhibits a higher surface gloss than those of other conventional resin materials, so that when an article is produced by assembling the parts made from various materials including a polyacetal resin, the polyacetal resin is inharmonious with the other materials. Therefore, the use of a polyacetal resin has been restricted not a little from the standpoint of surface appearance. A process for adding an inorganic filler such as calcium carbonate or talc to a polyacetal resin has been known as means for meeting the abo~e requirement of low surface glossiness.
According to this process, however, a large amount of talc or the like must be added in order to attain a desirable gloss-lowering effect, so that the resulting composition has another disadvantage that the mechanical characteristics, particularly elongation and toughness, are lowered to become liable 2~64~
to be broken by the stress applied during the post-processing or assembling of a molded article or the impact made on a molded article when, e.g., it is dropped during the handling thereof. Further, the polyacetal resin composition prepared according to the above process has another disadvantage that a molded article made therefrom causes surface deterioration (such as crack and discoloration) when exposed to sunlight (ultraviolet xays), rain and so on outdoors for a long period of time, because of the poor weathering resistance of the composition. Under these circumstances, the development of a polyacetal resin exhibiting lowered surface gloss and excellent weathering (light) resistance has been expected.
( Summary of the Invention ) , The inventors of the present invention have intensively studied for the purpose of lowering the surface gloss of a polyacetal resin and improving the weathering (light~ resistance thereof in the outdoor use without impairing the characteristics inherent in polyacetal resin and have accomplished the present invention.
Namely, the present invention provides a low-gloss polyacetal resin composition which comprises (A) 100 parts by weight of a polyacetal rasin and (B) o ~
0.1 to 40 parts by weight of a silicone graft copolymer prepared by the radical copolymerization of (a) an acrylic-modified silicone with (b) a radical-polymerizable monomer, another polyacetal resin composition which further contains (C) 0.01 to 5 parts by weight of a weathering (light) stabilizer in addition to the above essential components and which is lowered in surface gloss and exhibits excellent weathering resistance, and a low-gloss molded article made therefrom.
The constitution of the present invention will now be described in more detail.
First, the polyacetal resin (A) to be used in the pr sent invention is a high-molecular compound mainly composed of oxymethylene (-CH20-) units which may be either a polyoxymethylene homopolymer or a copolymer, terpolymer or block copolymer containing a small amount of other monomer(s) in addition to oxymethylene unitsO These (co)polymers may be linear, branched or crosslinked and the degree of polymerization thereof is not particularly limited.
Second, the silicone graft copolymer (B) to be used in the present invention is a high-molecular compound prepared by the radical copolymerization of (a) an acrylic-modified silicone with (b) a radical-;, 2~6~
polymerizable monomer. The acrylic-modified silicone (a) constituting the silicone graft copolymer (B) is a product of the condensation of a silicone represented by the following general formula (1) with an acryllc compound represented by the following general formula ~2):
R~
(1) HO ~ Si -D ~ H
wherein R1 and R2 are each an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, a phenyl group or a halogenated hydrocarbyl group;
and n is an integer of 2 or above, (2) CHa=C~C~O~CH~HaCHa- Si(Ri) 2X
O
and/or Ra CH2=C-C-O-CHzCH~CH~ ~ SiX3 wherein R3 is a hydrogen atom or a methyl group;
2 ~ 6 ~
R4 is a methyl, ethyl or phenyl group; and X is an alkoxy group having 1 to 10 carbon atoms, an acetoxy group or a chlorine atom.
The substituents R1 and R2 bonded to the silicon atom of the silicone represented by the above general formula (1) are each an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, a phenyl group or a halogenated hydrocarbyl group, preferably a methyl group.
The acrylic compound represented by the above general formula (2) includes ~-methacryloxypropyl-dimethylchlorosilane, ~-methacryloxypropyldiethoxy-silane, ~-methacryloxypropyldiethylchlorosilane, ~-acryloxypropyldimethylchlorosilane, ~-methacryloxy-propyltrichlorosilane and ~-methacryloxypropyltri-ethoxysilane.
Preferable examples of the acrylic-modified silicone (a) include condensation products of a,~
dihydroxypolydimethylsiloxane with ~-methacryloxy-propyldimethylchlorosilane and with ~-methacryloxy-propyltrichlorosilane.
N xt, the radical-polymerizable monomer (b) constituting the silicone graft copolymer (B) includes methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl 2 ~ 6 ~
methacrylate, cyclohexyl methacrylate, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, styrene, vinyl esters of organic acids such as vinyl acetate and low-molecular-weight, straight-chain hydrocarbons such as ethylene and propylene.
Among the monomers listed above, it is preferable to use acrylic or methacrylic acid or an ester thereof, still preferably acrylic acid, methyl acrylate, methacrylic acid or methyl methacrylate.
Among silicone graft copolymers prepared from the components as described above, it is particularly preferable to use one prepared by the radical copolymerization of (a) a condensation product of u,~
dihydroxypolydimethylsiloxane with ~-methacryloxy-propyldimethylchlorosilane with (b) methyl acrylate or methyl methacrylate.
The silicone graft copolymer (B) to be used in the present invention is characterized in that the acrylic-modified silicone polymer (a) and the radical-polymerizable monomer or polymer thereof (b), both of which constitute the main backbone chain of the copolymer (B), are used not each alone but as a graft copolymer of the both. As will be descrlbed below, remarbale effect can be attained in the present invention by virtue of this graft structure, whereas 2~6~9 the effect cannot be attained b~ the addition of the component (a) or (b) alone.
Although the process for the preparation of the graft copolymer is not particularly limited, for example, the acrylic-modified silicone (a) constituting the sillcone graft copolymer (B) can be very easily prepared by a conventional condensation process. That is, when an acrylic compound represented by the general formula (2) whereln X is a chlorine atom is used, the condensation may be conducted through dehydrochlorination in the presence of an acid acceptor, while when an acrylic compound represented by the general formula (2) wherein X is a methoxy or ethoxy group is used, the condensation may be conducted through elimination of an alcohol-molecule. In the condensation, the compound represented by the general formula (2) and the silicone represented by the general formula (1) may be used in such amounts as to give an e~uivalent ratio of the Si-X group to the SiOH group of between 0O25 and 1. When the amount of the compound (2) is too large, the resulting silicone graft copolymer (B) will be liable to gel easily, while when the ratio is less than 0.25, a large amount o~ unreacted silicone will remain unfavorably.
" 2n~4~
The acrylic-modified silicone (a) prepared by the above process can be very smoothly copolymerized with a conventional radical-polymerlzable monomer to give a sllicone graft copolymer (B). It is desirable that the amounts of the components (a) and (b) constituting the silicone graft copolymer (B) be selected so as to give a silicone graft copolymer having a silicone content of 5 to 80% by weight, preferably 10 to 70% by weight.
Although the molecular weight of the graft copolymer thus prepared is not particularly limited, it is generally 1000 to 200000, preferably 5000 to lS0000.
According to the present invention, the amount of the component (B) to be used is 0.1 to 40 parts by weight, preferably 5 to 20 parts by weight per 100 parts by weight of the component (A). When the amount of the component (B) is too small, the surface gloss-lowering effect will not sufficiently be attained, while when it is too large, the mechanical properties and/or the heat stability will be adversely affected and economic disadvantage will be brought about.
A molded article made from a composition comprising a polyacetal resin (A) and the silicone graft copolymer (B) is uniformly lGwered in surface i~
gloss to acquire a profound and high grade appearance and is sufficiently improved in weathering (light) resistance. The reasons why the surface gloss is lowered are thought to be that part of the silicone graft copolymer (B) dispersed in the molded article in the form of a particle having a size of 0.5 to 2 ~m reaches the surface of the article to roughen the surface, thus lowering the gloss thereof and that the silicone moiety uniformly dispersed in the surface area covers the polyacetal resin to lower the surface gloss. A practically desirable surface gloss is 40%
or below, still preferably 15% or below as determined by the process which will be described below, though the surface gloss varies depending upon molding conditions and the degree of mold surface finishing.
Although the composition of the present invention exhibits low gloss and excellent weathering resistance even when used as such, the additional use of a weathering (light) stabilizer (C) is more effective in improving the weathering (light) resistance, particularly inhibiting the crack of the surface of the molded article and the discoloration thereof.
The weathering (light) stabilizer to be preferably used in the present invention is one or more members selected from the group consisting of (1) i i 2~B~
benzotriazoles, (2) benzophenones, (3) oxanilides, (4) aromatic benzoates, (5) cyanoacrylates and (6) hindered amines.
Examples of the stabilizer are as follows.
Namely, examples of the benzotriazole (1) include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-diisoamylphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis( a, a-dimethylbenzyl)phenyl]-benzotriazole and 2-(2'-hydroxy-4'-octoxyphenyl)-benzotriazole.
Examples of the benzophenones (2) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxy benzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and 2-hydroxy-4-oxybenzylbenzophenone.
Examples of the oxanilindes (3) include N-(2-ethylphenyl)-N'-(2-ethoxy-5-t-butylphenyl)oxanilide and N-(2-ethylphenyl)-N'-(2-ethoxyphenyl)oxanilide.
Examples of the aromatic benzoates (4) include p-t-butylphenyl salicylate and p-octylphenyl salicylate.
2 ~ 9 Examples of the cyanoacrylates (5) include 2-ethylhexyl 2-cyano 3,3-diphenylacrylate and ethyl 2-cyano-3,3-diphenylacrylate.
The hindered amines (6) are piperidine derivatives each having a sterically hindering 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-tetra-methylpiperidine, 4-phenoxy-2,2,6,6-tetramethyl-piperidine, 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-peptamethyl-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-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate, bis(1-methyl-2,2,6,6-tetramethyl-4-piperidyl) adipate and tris(2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate. Further, 1 ~ 2 ~ 9 high-molecular polycondensates of piperidine derivatives, such as dimethyl succinate-l-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethyl-piperidine polycondensate, are effectively used.
According to the present invention, one or more of the above weathering (light) stabilizers may be used. Particularly, the simultaneous use of one of the above stabilizers(l) to (5) with a hindered amine (6) is effective and, more particularly, the simultaneous use of a benzotriazole (1) with a hindered amine (6) is most effective.
The weathering (light) stabilizer (C) may be used in an amount of 0.01 to 5 parts by weight, preferably 0.02 to 3 parts by weight, per 100 parts by weight of the component (A). When the amount of the stabilizer (C) is too small, no effect will be attained, while the use thereof in too large an amount will bring about not only an economic disadvantage but also lowering in the mechanical properties or pollution of a mold.
Although even a composition prepared by adding a weathering (light) stabilizer (C) alone to a polyacetal resin exhibits fairly excellent weathexing resistance, the weathering resistance is not enough to withstand the long-term exposure to sunllght 1 ~ 2~
(ultraviolet rays) or rain outdoors. The use of a weathering (light) stabilizer together with the silicone graft copolymer (B) can give a molded article exhibiting low surface gloss and more improved weathering resistance. Further, it is desirable that the composition of the present invention further contain various known stabilizers in order to improve the heat stability and so on. For this purpose, it is desirable to use one or more members selected from among known antioxidants, nitrogenous compounds and alkali and alkaline earth metal compounds.
Furthermore, the composition of the present invention may be arbitrarily colored by the addition of various carbon blacks or other dyes or pigments.
Particularly, the use of carbon black is effective in further improving the weathering (light) resistance of the composition~
The composition of the present invention may further contain one or more conventional additives in order to impart desirable characteristics thereto depending upon the object and examples of the additives include lubricant, nucleating agent, mold release agent, anbistatic agent, other surfactant, organic high-molecular materials other than the component (B) and inorganic or organic, fibrous, l ;j 2 ~ 9 granular, powdery or flaky fillers.
The additlonal use of a known additive having a gloss-lowering effect (for example~ talc, calcium carbonate or aluminum silicate) is somewhat effective.
The composition of the present invention can be prepared by a conventional process for the preparation of a synthetic resin composition with conventional equipment therefor. Namely, necessary components are mixed together and kneaded and extruded with a single-or twin-screw extruder to give pellets, followed by the molding of the pellets. Alternatively, the preparation of the composition may be conducted in a molding machine simultaneously with the molding thereof. Further, a process which comprises pulverizing a part or the whole of the resin components, mixing the pulverized components with the residual components, melt-extruding the obtained mixture to give pellets and molding the pellets may be employed.
The above stabilizers and additives may be added in any arbitrary step and, of course, even just before the production of a final molded article.
The resin composition of the present invention may be molded by extrusion, injection, compression, vacuum blow or expansion molding.
lt~ 20~69 As described above, the composition of the present invention comprising a polyacetal resin and a specific silicone graft copolymer exhibits an effect of giving a molded article which is remarkably lowered in surface gloss without impairing the well-balanced mechanical properties inherent in a polyacetal resin.
Further, the composition containing a weathering (light) stabilizer in addition to the above components is further improved in weathering resistance which has been problematic when an inorganic filler (such as talc or calcium carbonate) is used. Particularly, it exhibits a remarkably lengthened crack initiation time and reduced discoloration.
Accordingly, the low-gloss polyacetal resin composition of the present invention can be favorably used in the production of various molded articles necessitating high-grade appearances and high weathering (light) resistance, i.e., automotive internal trim parts (such as inner handle, regulator handle and trim clip) and in the fields which are required to have a profound appearance in spite of long-term exposure to sunlight and rain, for example, automotive exterior trim parts (such as outer handle and fuel lid), electrical appliances, building materials, cameras and housewares.
2 0 ~ 9 [Exarnple]
The present invention wi~l now be described by referring to the following Examples, though the present invention is not limited by them.
In the Examples, characteristic values such as surface appearance, weathering (light) resistance and so on were determined by the following methods.
(1) Surface appearance The surface appearance was ranked according to the following four criteria based on the dullness and uniformity of the surface, wherein a smaller numeral represents a state of more excellent dullness and uniformity.
l...when a sample was irradiated with a fluorescent lamp, no outlines of the lamp were recognized on the surface of a sample and the surface was uniformly rough.
2...the surface of a sample was ununiformly rough though no outlines of a fluorescent lamp were recognized on the surface.
ARTICLE
[Field of Industrial Application]
The present invention relates to a polyacetal resin composition which is lowered in surface gloss and exhibits excellent weathering ~light) resistance.
More particularly, the present invention pxovides a polyacetal resin composition which comprises a polyacetal resin, a specific silicone yraft copolymer and, if necessary, a weathering (light) stabilizer and which is lowered in surface gloss and improved in weathering resistance without impairing the well-balanced mechanical properties inherent in a polyacetal resin, and a molded article thereof.
[Prior Art As well known, a polyacetal rewin has recently been used in various fields as an engineering plastic excellent both in physical characteristics such as mechanical and electrical properties and in chemical characteristics such as resistance~ to chemicals and heat. As the field of use of a pol~acetal resin has been enlaxged, however, the resin has been frequently required to exhibit more special properties as materials.
One of such properties is low glossiness, i.e., low light reflectivity, which is requixed in the fields of automotive trim parts and optical ;~ 2~4~
instruments for the purpose of reducing the irritations to the eye due to the reflection of light, inhibiting the malfunction of devices and imparting a high-grade appearance. Meanwhile chances of using two or more materials combined depending upon the object have also increased in the fields of electrical appliances and building materials. In such cases, a polyacetal resin exhibits a higher surface gloss than those of other conventional resin materials, so that when an article is produced by assembling the parts made from various materials including a polyacetal resin, the polyacetal resin is inharmonious with the other materials. Therefore, the use of a polyacetal resin has been restricted not a little from the standpoint of surface appearance. A process for adding an inorganic filler such as calcium carbonate or talc to a polyacetal resin has been known as means for meeting the abo~e requirement of low surface glossiness.
According to this process, however, a large amount of talc or the like must be added in order to attain a desirable gloss-lowering effect, so that the resulting composition has another disadvantage that the mechanical characteristics, particularly elongation and toughness, are lowered to become liable 2~64~
to be broken by the stress applied during the post-processing or assembling of a molded article or the impact made on a molded article when, e.g., it is dropped during the handling thereof. Further, the polyacetal resin composition prepared according to the above process has another disadvantage that a molded article made therefrom causes surface deterioration (such as crack and discoloration) when exposed to sunlight (ultraviolet xays), rain and so on outdoors for a long period of time, because of the poor weathering resistance of the composition. Under these circumstances, the development of a polyacetal resin exhibiting lowered surface gloss and excellent weathering (light) resistance has been expected.
( Summary of the Invention ) , The inventors of the present invention have intensively studied for the purpose of lowering the surface gloss of a polyacetal resin and improving the weathering (light~ resistance thereof in the outdoor use without impairing the characteristics inherent in polyacetal resin and have accomplished the present invention.
Namely, the present invention provides a low-gloss polyacetal resin composition which comprises (A) 100 parts by weight of a polyacetal rasin and (B) o ~
0.1 to 40 parts by weight of a silicone graft copolymer prepared by the radical copolymerization of (a) an acrylic-modified silicone with (b) a radical-polymerizable monomer, another polyacetal resin composition which further contains (C) 0.01 to 5 parts by weight of a weathering (light) stabilizer in addition to the above essential components and which is lowered in surface gloss and exhibits excellent weathering resistance, and a low-gloss molded article made therefrom.
The constitution of the present invention will now be described in more detail.
First, the polyacetal resin (A) to be used in the pr sent invention is a high-molecular compound mainly composed of oxymethylene (-CH20-) units which may be either a polyoxymethylene homopolymer or a copolymer, terpolymer or block copolymer containing a small amount of other monomer(s) in addition to oxymethylene unitsO These (co)polymers may be linear, branched or crosslinked and the degree of polymerization thereof is not particularly limited.
Second, the silicone graft copolymer (B) to be used in the present invention is a high-molecular compound prepared by the radical copolymerization of (a) an acrylic-modified silicone with (b) a radical-;, 2~6~
polymerizable monomer. The acrylic-modified silicone (a) constituting the silicone graft copolymer (B) is a product of the condensation of a silicone represented by the following general formula (1) with an acryllc compound represented by the following general formula ~2):
R~
(1) HO ~ Si -D ~ H
wherein R1 and R2 are each an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, a phenyl group or a halogenated hydrocarbyl group;
and n is an integer of 2 or above, (2) CHa=C~C~O~CH~HaCHa- Si(Ri) 2X
O
and/or Ra CH2=C-C-O-CHzCH~CH~ ~ SiX3 wherein R3 is a hydrogen atom or a methyl group;
2 ~ 6 ~
R4 is a methyl, ethyl or phenyl group; and X is an alkoxy group having 1 to 10 carbon atoms, an acetoxy group or a chlorine atom.
The substituents R1 and R2 bonded to the silicon atom of the silicone represented by the above general formula (1) are each an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, a phenyl group or a halogenated hydrocarbyl group, preferably a methyl group.
The acrylic compound represented by the above general formula (2) includes ~-methacryloxypropyl-dimethylchlorosilane, ~-methacryloxypropyldiethoxy-silane, ~-methacryloxypropyldiethylchlorosilane, ~-acryloxypropyldimethylchlorosilane, ~-methacryloxy-propyltrichlorosilane and ~-methacryloxypropyltri-ethoxysilane.
Preferable examples of the acrylic-modified silicone (a) include condensation products of a,~
dihydroxypolydimethylsiloxane with ~-methacryloxy-propyldimethylchlorosilane and with ~-methacryloxy-propyltrichlorosilane.
N xt, the radical-polymerizable monomer (b) constituting the silicone graft copolymer (B) includes methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl 2 ~ 6 ~
methacrylate, cyclohexyl methacrylate, acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, styrene, vinyl esters of organic acids such as vinyl acetate and low-molecular-weight, straight-chain hydrocarbons such as ethylene and propylene.
Among the monomers listed above, it is preferable to use acrylic or methacrylic acid or an ester thereof, still preferably acrylic acid, methyl acrylate, methacrylic acid or methyl methacrylate.
Among silicone graft copolymers prepared from the components as described above, it is particularly preferable to use one prepared by the radical copolymerization of (a) a condensation product of u,~
dihydroxypolydimethylsiloxane with ~-methacryloxy-propyldimethylchlorosilane with (b) methyl acrylate or methyl methacrylate.
The silicone graft copolymer (B) to be used in the present invention is characterized in that the acrylic-modified silicone polymer (a) and the radical-polymerizable monomer or polymer thereof (b), both of which constitute the main backbone chain of the copolymer (B), are used not each alone but as a graft copolymer of the both. As will be descrlbed below, remarbale effect can be attained in the present invention by virtue of this graft structure, whereas 2~6~9 the effect cannot be attained b~ the addition of the component (a) or (b) alone.
Although the process for the preparation of the graft copolymer is not particularly limited, for example, the acrylic-modified silicone (a) constituting the sillcone graft copolymer (B) can be very easily prepared by a conventional condensation process. That is, when an acrylic compound represented by the general formula (2) whereln X is a chlorine atom is used, the condensation may be conducted through dehydrochlorination in the presence of an acid acceptor, while when an acrylic compound represented by the general formula (2) wherein X is a methoxy or ethoxy group is used, the condensation may be conducted through elimination of an alcohol-molecule. In the condensation, the compound represented by the general formula (2) and the silicone represented by the general formula (1) may be used in such amounts as to give an e~uivalent ratio of the Si-X group to the SiOH group of between 0O25 and 1. When the amount of the compound (2) is too large, the resulting silicone graft copolymer (B) will be liable to gel easily, while when the ratio is less than 0.25, a large amount o~ unreacted silicone will remain unfavorably.
" 2n~4~
The acrylic-modified silicone (a) prepared by the above process can be very smoothly copolymerized with a conventional radical-polymerlzable monomer to give a sllicone graft copolymer (B). It is desirable that the amounts of the components (a) and (b) constituting the silicone graft copolymer (B) be selected so as to give a silicone graft copolymer having a silicone content of 5 to 80% by weight, preferably 10 to 70% by weight.
Although the molecular weight of the graft copolymer thus prepared is not particularly limited, it is generally 1000 to 200000, preferably 5000 to lS0000.
According to the present invention, the amount of the component (B) to be used is 0.1 to 40 parts by weight, preferably 5 to 20 parts by weight per 100 parts by weight of the component (A). When the amount of the component (B) is too small, the surface gloss-lowering effect will not sufficiently be attained, while when it is too large, the mechanical properties and/or the heat stability will be adversely affected and economic disadvantage will be brought about.
A molded article made from a composition comprising a polyacetal resin (A) and the silicone graft copolymer (B) is uniformly lGwered in surface i~
gloss to acquire a profound and high grade appearance and is sufficiently improved in weathering (light) resistance. The reasons why the surface gloss is lowered are thought to be that part of the silicone graft copolymer (B) dispersed in the molded article in the form of a particle having a size of 0.5 to 2 ~m reaches the surface of the article to roughen the surface, thus lowering the gloss thereof and that the silicone moiety uniformly dispersed in the surface area covers the polyacetal resin to lower the surface gloss. A practically desirable surface gloss is 40%
or below, still preferably 15% or below as determined by the process which will be described below, though the surface gloss varies depending upon molding conditions and the degree of mold surface finishing.
Although the composition of the present invention exhibits low gloss and excellent weathering resistance even when used as such, the additional use of a weathering (light) stabilizer (C) is more effective in improving the weathering (light) resistance, particularly inhibiting the crack of the surface of the molded article and the discoloration thereof.
The weathering (light) stabilizer to be preferably used in the present invention is one or more members selected from the group consisting of (1) i i 2~B~
benzotriazoles, (2) benzophenones, (3) oxanilides, (4) aromatic benzoates, (5) cyanoacrylates and (6) hindered amines.
Examples of the stabilizer are as follows.
Namely, examples of the benzotriazole (1) include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-diisoamylphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis( a, a-dimethylbenzyl)phenyl]-benzotriazole and 2-(2'-hydroxy-4'-octoxyphenyl)-benzotriazole.
Examples of the benzophenones (2) include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxy benzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and 2-hydroxy-4-oxybenzylbenzophenone.
Examples of the oxanilindes (3) include N-(2-ethylphenyl)-N'-(2-ethoxy-5-t-butylphenyl)oxanilide and N-(2-ethylphenyl)-N'-(2-ethoxyphenyl)oxanilide.
Examples of the aromatic benzoates (4) include p-t-butylphenyl salicylate and p-octylphenyl salicylate.
2 ~ 9 Examples of the cyanoacrylates (5) include 2-ethylhexyl 2-cyano 3,3-diphenylacrylate and ethyl 2-cyano-3,3-diphenylacrylate.
The hindered amines (6) are piperidine derivatives each having a sterically hindering 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-tetra-methylpiperidine, 4-phenoxy-2,2,6,6-tetramethyl-piperidine, 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-peptamethyl-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-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate, bis(1-methyl-2,2,6,6-tetramethyl-4-piperidyl) adipate and tris(2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate. Further, 1 ~ 2 ~ 9 high-molecular polycondensates of piperidine derivatives, such as dimethyl succinate-l-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethyl-piperidine polycondensate, are effectively used.
According to the present invention, one or more of the above weathering (light) stabilizers may be used. Particularly, the simultaneous use of one of the above stabilizers(l) to (5) with a hindered amine (6) is effective and, more particularly, the simultaneous use of a benzotriazole (1) with a hindered amine (6) is most effective.
The weathering (light) stabilizer (C) may be used in an amount of 0.01 to 5 parts by weight, preferably 0.02 to 3 parts by weight, per 100 parts by weight of the component (A). When the amount of the stabilizer (C) is too small, no effect will be attained, while the use thereof in too large an amount will bring about not only an economic disadvantage but also lowering in the mechanical properties or pollution of a mold.
Although even a composition prepared by adding a weathering (light) stabilizer (C) alone to a polyacetal resin exhibits fairly excellent weathexing resistance, the weathering resistance is not enough to withstand the long-term exposure to sunllght 1 ~ 2~
(ultraviolet rays) or rain outdoors. The use of a weathering (light) stabilizer together with the silicone graft copolymer (B) can give a molded article exhibiting low surface gloss and more improved weathering resistance. Further, it is desirable that the composition of the present invention further contain various known stabilizers in order to improve the heat stability and so on. For this purpose, it is desirable to use one or more members selected from among known antioxidants, nitrogenous compounds and alkali and alkaline earth metal compounds.
Furthermore, the composition of the present invention may be arbitrarily colored by the addition of various carbon blacks or other dyes or pigments.
Particularly, the use of carbon black is effective in further improving the weathering (light) resistance of the composition~
The composition of the present invention may further contain one or more conventional additives in order to impart desirable characteristics thereto depending upon the object and examples of the additives include lubricant, nucleating agent, mold release agent, anbistatic agent, other surfactant, organic high-molecular materials other than the component (B) and inorganic or organic, fibrous, l ;j 2 ~ 9 granular, powdery or flaky fillers.
The additlonal use of a known additive having a gloss-lowering effect (for example~ talc, calcium carbonate or aluminum silicate) is somewhat effective.
The composition of the present invention can be prepared by a conventional process for the preparation of a synthetic resin composition with conventional equipment therefor. Namely, necessary components are mixed together and kneaded and extruded with a single-or twin-screw extruder to give pellets, followed by the molding of the pellets. Alternatively, the preparation of the composition may be conducted in a molding machine simultaneously with the molding thereof. Further, a process which comprises pulverizing a part or the whole of the resin components, mixing the pulverized components with the residual components, melt-extruding the obtained mixture to give pellets and molding the pellets may be employed.
The above stabilizers and additives may be added in any arbitrary step and, of course, even just before the production of a final molded article.
The resin composition of the present invention may be molded by extrusion, injection, compression, vacuum blow or expansion molding.
lt~ 20~69 As described above, the composition of the present invention comprising a polyacetal resin and a specific silicone graft copolymer exhibits an effect of giving a molded article which is remarkably lowered in surface gloss without impairing the well-balanced mechanical properties inherent in a polyacetal resin.
Further, the composition containing a weathering (light) stabilizer in addition to the above components is further improved in weathering resistance which has been problematic when an inorganic filler (such as talc or calcium carbonate) is used. Particularly, it exhibits a remarkably lengthened crack initiation time and reduced discoloration.
Accordingly, the low-gloss polyacetal resin composition of the present invention can be favorably used in the production of various molded articles necessitating high-grade appearances and high weathering (light) resistance, i.e., automotive internal trim parts (such as inner handle, regulator handle and trim clip) and in the fields which are required to have a profound appearance in spite of long-term exposure to sunlight and rain, for example, automotive exterior trim parts (such as outer handle and fuel lid), electrical appliances, building materials, cameras and housewares.
2 0 ~ 9 [Exarnple]
The present invention wi~l now be described by referring to the following Examples, though the present invention is not limited by them.
In the Examples, characteristic values such as surface appearance, weathering (light) resistance and so on were determined by the following methods.
(1) Surface appearance The surface appearance was ranked according to the following four criteria based on the dullness and uniformity of the surface, wherein a smaller numeral represents a state of more excellent dullness and uniformity.
l...when a sample was irradiated with a fluorescent lamp, no outlines of the lamp were recognized on the surface of a sample and the surface was uniformly rough.
2...the surface of a sample was ununiformly rough though no outlines of a fluorescent lamp were recognized on the surface.
3...the outlines of a fluorescent lamp were recognized on the surface of a sample, though they were indistinct.
4...distinct outlines of a fluorescent lamp were recognlzed on the surface and the surace was 4 ~
nearly smooth.
(2) Surface gloss The gloss of a test piece (70 mm x 40 mm x 3 mm) prepared by molding under the followlng conditions was determined according to the method of JIS K 7105 with a variable angle digital glossmeter (mfd. by Suga Test Instruments Co., Ltd.; UGV-40) at 45-45 reflection.
O molding machine: mfd. by Toshiba Corporation, O moldinq conditions:
nozzle Cl C2 C3 cylinder temp. 200 190 180 160 (C) injection 650 (kgtcm2) pressure injection 1.0 (m/min) speed mold temp. 80 (C) (3) Weathering test A test piece was irradiated with ultraviolet rays in a weathermeter (mfd. by Suga Test Instruments Co., Ltd., WBL-SUN-HCH type) under the conditions of a black panel temperature of 63C and weathering (including the spray with rain) to determine the crack initiation time and the change in the surface appearance.
~ crack initiation time 1~ 2~646~
A test piece was irradiated with ultraviolet rays under the above conditions. The sur~ace of the test piece was observed with a 10 x magnifier to determine the time elapsed until crack was recognized ~or the first time. This time was regarded as the crack initiation time. A higher value means a better weathering resistance.
~ change in the surface appearance A test piece was irradiated with ultraviolet rays under the above conditions for a predetermined time (600, 1000 or 2000 hours) to observe changes in the hue of the test piece before and after the irradiation and the crack. The observed changes were indicated by five ranks. A smaller numeral means less changes, i.e., less discoloration and less crack.
(4) Tensile test The tensile strength and tensile elongation were determined according to ASTM D 638.
Examples 1 to 19 and Comparative Examples 1 to 17 As shown in Table 1, a polyacetal resin (A) [a product of Polyplastics; trade name "Duracon (MgO)~
was mixed with a silicone graft copolymer (B) alone or together with a weathering (light) stabilizer (C) and, if necessary, carbon black. The obtained mixture was melt-kneaded with a 30-mm twin-screw extruder to give ~() a pelletized composition. Thls composition was molded into a test piece with an lnjection molding machlne.
This test piece was examined for gloss, weathering resistance and other characterlstics. For comparison, the same procedure as that described above was repeated except that ungrafted silicone oil, an acrylic resin, a weathering (light) stabilizer and/or a conventional additive having a gloss-lowering effect were used instead of the component (B) as specified in Table 2. The results are given in Tables 1 and 2.
2 ~ 9 ~1 _ O O m O ~ ~ ~. ~ _ _ _ _ L I Ln o ~' _ _ ~D O
-0 ~ ; 1~ Un' _ _ _ _ N- _ ~ ~
O O .1 O I O L L`~ r-~ O N ~ ~ ~') O Ln _ O ~1 C~ '.'.10 _ __ -_ L O-_ _ _~ ., Z ~/1 O O O O r L ~ N .-1 N _ .-1 L/~
g ~
~' ~
2 ~ 9 _~ ~ o~ ~ __ _ o, _ ~ ~ _ _ _ ~I ~
~ ~ , ~
'~0 EQ' ~ ~ i ~ ~ ~ ___ _ , ~ ~ ~ ~ ~
~1 O l O t.) O t.) O _ _ _ _ ~ o _ N _ ~_ o 4 ~ ~ ~
V V Q. O J~J 3 _ ~ 3 V V ~ JJ C "
e I .a 4 ,4 1:: ''I a) C . .~
_ ~ _, ~ ~ P. ~ ~ ~ O ~ ~ a~ ~ o ~ ~
_I tJ~ ~ h 3 ~1 ~r o . ~_ ,~ ~ ,~: j a v _ _ o ---- ~ ----~ . _ ~ L L ~
~ i ~ ~ ~
_ ~ ~ `
_ r o _ -- ~ o tJ o _ _ o o N N N _ Itl _ _ N
~D O _ _ ~.) O ~ O N O _ O _ r o _ _ _ r1 N
Z u~ o _ _ C.)~ ~o _ o _ _ _ r o N _ _ It> O
X ~r o 1~ o ~.) o o N 0 O 'r It) "_, 0:1 N
:' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ O ~ ~ O t.) O ~ O N O ~ r o ~r u~ ~ ~ N
~.1 ~3 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ N N O ~ O O O N ~r U~ N 1-~ Il) 1~1 r o ~0 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ,~ o t~ o ~ o ~ r o ~7 u~ u~ r N
o o _ ~ o~ L _r o---- _ ~ _ ~1 N ~ V O C O E
3 o ~:L o O ~ ~ ~ ~ o n 4~ q~ a ~ 3 3 A 3 ~ a C O v Q. ~ ~ 0 o nl S~ ~ 0 O
~J
~\ O . N :~ O A m o .r~
_ _ 3 u~-- o ~ ~ ~ u o I J ."
~ ~ ~ .~ _ 0 m o ,1 3 C) O
note 1) B-1: copolymer comprising methyl methacrylate and an acrylic-modified silicone prepared from a,~-dihydroxypolydimethylsiloxane and ~-methacryloxypropyldimethylchlorosilane B-2: copolymer comprising methyl methacrylate and an acrylic-modified silicone prepared from a,~fdihydroxypolydimethylsiloxane and ~-methacryloxypropyltrichlorosilane note 2) C-1: 2-[2-hydroxy-3,5-bis(a,a-dimethylbenzyl)-phenyl]benzotriazole C-2: 2-hydroxy-4-oxybenzylbenzophenone C-3: bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate C-4: dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate
nearly smooth.
(2) Surface gloss The gloss of a test piece (70 mm x 40 mm x 3 mm) prepared by molding under the followlng conditions was determined according to the method of JIS K 7105 with a variable angle digital glossmeter (mfd. by Suga Test Instruments Co., Ltd.; UGV-40) at 45-45 reflection.
O molding machine: mfd. by Toshiba Corporation, O moldinq conditions:
nozzle Cl C2 C3 cylinder temp. 200 190 180 160 (C) injection 650 (kgtcm2) pressure injection 1.0 (m/min) speed mold temp. 80 (C) (3) Weathering test A test piece was irradiated with ultraviolet rays in a weathermeter (mfd. by Suga Test Instruments Co., Ltd., WBL-SUN-HCH type) under the conditions of a black panel temperature of 63C and weathering (including the spray with rain) to determine the crack initiation time and the change in the surface appearance.
~ crack initiation time 1~ 2~646~
A test piece was irradiated with ultraviolet rays under the above conditions. The sur~ace of the test piece was observed with a 10 x magnifier to determine the time elapsed until crack was recognized ~or the first time. This time was regarded as the crack initiation time. A higher value means a better weathering resistance.
~ change in the surface appearance A test piece was irradiated with ultraviolet rays under the above conditions for a predetermined time (600, 1000 or 2000 hours) to observe changes in the hue of the test piece before and after the irradiation and the crack. The observed changes were indicated by five ranks. A smaller numeral means less changes, i.e., less discoloration and less crack.
(4) Tensile test The tensile strength and tensile elongation were determined according to ASTM D 638.
Examples 1 to 19 and Comparative Examples 1 to 17 As shown in Table 1, a polyacetal resin (A) [a product of Polyplastics; trade name "Duracon (MgO)~
was mixed with a silicone graft copolymer (B) alone or together with a weathering (light) stabilizer (C) and, if necessary, carbon black. The obtained mixture was melt-kneaded with a 30-mm twin-screw extruder to give ~() a pelletized composition. Thls composition was molded into a test piece with an lnjection molding machlne.
This test piece was examined for gloss, weathering resistance and other characterlstics. For comparison, the same procedure as that described above was repeated except that ungrafted silicone oil, an acrylic resin, a weathering (light) stabilizer and/or a conventional additive having a gloss-lowering effect were used instead of the component (B) as specified in Table 2. The results are given in Tables 1 and 2.
2 ~ 9 ~1 _ O O m O ~ ~ ~. ~ _ _ _ _ L I Ln o ~' _ _ ~D O
-0 ~ ; 1~ Un' _ _ _ _ N- _ ~ ~
O O .1 O I O L L`~ r-~ O N ~ ~ ~') O Ln _ O ~1 C~ '.'.10 _ __ -_ L O-_ _ _~ ., Z ~/1 O O O O r L ~ N .-1 N _ .-1 L/~
g ~
~' ~
2 ~ 9 _~ ~ o~ ~ __ _ o, _ ~ ~ _ _ _ ~I ~
~ ~ , ~
'~0 EQ' ~ ~ i ~ ~ ~ ___ _ , ~ ~ ~ ~ ~
~1 O l O t.) O t.) O _ _ _ _ ~ o _ N _ ~_ o 4 ~ ~ ~
V V Q. O J~J 3 _ ~ 3 V V ~ JJ C "
e I .a 4 ,4 1:: ''I a) C . .~
_ ~ _, ~ ~ P. ~ ~ ~ O ~ ~ a~ ~ o ~ ~
_I tJ~ ~ h 3 ~1 ~r o . ~_ ,~ ~ ,~: j a v _ _ o ---- ~ ----~ . _ ~ L L ~
~ i ~ ~ ~
_ ~ ~ `
_ r o _ -- ~ o tJ o _ _ o o N N N _ Itl _ _ N
~D O _ _ ~.) O ~ O N O _ O _ r o _ _ _ r1 N
Z u~ o _ _ C.)~ ~o _ o _ _ _ r o N _ _ It> O
X ~r o 1~ o ~.) o o N 0 O 'r It) "_, 0:1 N
:' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ O ~ ~ O t.) O ~ O N O ~ r o ~r u~ ~ ~ N
~.1 ~3 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ N N O ~ O O O N ~r U~ N 1-~ Il) 1~1 r o ~0 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ,~ o t~ o ~ o ~ r o ~7 u~ u~ r N
o o _ ~ o~ L _r o---- _ ~ _ ~1 N ~ V O C O E
3 o ~:L o O ~ ~ ~ ~ o n 4~ q~ a ~ 3 3 A 3 ~ a C O v Q. ~ ~ 0 o nl S~ ~ 0 O
~J
~\ O . N :~ O A m o .r~
_ _ 3 u~-- o ~ ~ ~ u o I J ."
~ ~ ~ .~ _ 0 m o ,1 3 C) O
note 1) B-1: copolymer comprising methyl methacrylate and an acrylic-modified silicone prepared from a,~-dihydroxypolydimethylsiloxane and ~-methacryloxypropyldimethylchlorosilane B-2: copolymer comprising methyl methacrylate and an acrylic-modified silicone prepared from a,~fdihydroxypolydimethylsiloxane and ~-methacryloxypropyltrichlorosilane note 2) C-1: 2-[2-hydroxy-3,5-bis(a,a-dimethylbenzyl)-phenyl]benzotriazole C-2: 2-hydroxy-4-oxybenzylbenzophenone C-3: bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate C-4: dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate
Claims (8)
1. A low-gloss polyacetal resin composition comprising (A) 100 parts by weight of a polyacetal resin and (B). 0.1 to 40 parts by weight of a silicone graft copolymer prepared by the radical copolymerization of (a) an acrylic-modified silicone with (b) a radical-polymerizable monomer.
2. A low-gloss polyacetal resin composition as set forth in claim 1, wherein said acrylic-modified silicone (a) constituting the component (B) is a product of the condensation of a silicone represented by the following general formula (1) with an acrylic compound represented by the following general formula (2):
wherein R1 and R2 are each an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, a phenyl group or a halogenated hydrocarbyl group;
and n is an integer of 2 or above, and/or wherein R3 is a hydrogen atom or a methyl group;
R4 is a methyl, ethyl or phenyl group; and X is an alkoxy group having 1 to 10 carbon atoms, an acetoxy group or a chlorine atom.
wherein R1 and R2 are each an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, a phenyl group or a halogenated hydrocarbyl group;
and n is an integer of 2 or above, and/or wherein R3 is a hydrogen atom or a methyl group;
R4 is a methyl, ethyl or phenyl group; and X is an alkoxy group having 1 to 10 carbon atoms, an acetoxy group or a chlorine atom.
3. A low-gloss polyacetal resin composition an set forth in claim 1 or 2, wherein the acrylic-modified silicone (a) constituting the component (B) is a product of the condensation of .alpha.,.omega.-dihydroxypoly-dimethylsiloxane with .gamma.-methacryloxypropyldimethyl-chlorosilane or .gamma.-methacryloxypropyltrichlorosilane.
4. A low-gloss polyacetal resin composition as set forth in any of claims 1 to 3, wherein the radical-polymerizable monomer (b) constituting the component (B) is acrylic or methacrylic acid or an ester thereof.
5. A low-gloss polyacetal resin composition as se forth in any of claims 1 to 4 which further contains (C) 0.01 to 5 parts by weight (per 100 parts by weight of the polyacetal) of a weathering (light) stabilizer.
6. A low-gloss polyacetal resin composition as set forth in claim 5, wherein said weathering (light) stabilizer (C) is one or more members selected from the group consisting of benzotriazoles, benzophenones, oxanilides, aromatic benzoates, cyanoacrylates and hindered amines.
7. A low-gloss polyacetal resin composition as set forth in claim 5 or 6, wherein said weathering (light) stabilizer (C) comprises a combination of one or more members selected from among benzotriazoles, benzophenones, oxanilides, aromatic benzoates and cyanoacrylates with a hindered amine.
8. A molded article of a low-gloss polyacetal resin made by molding the composition as set forth in any of claims 1 to 7.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2/181,117 | 1990-07-09 | ||
| JP2181117A JP2818475B2 (en) | 1990-07-09 | 1990-07-09 | Low gloss polyacetal resin composition and molded article |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2046469A1 true CA2046469A1 (en) | 1992-01-10 |
Family
ID=16095149
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002046469A Abandoned CA2046469A1 (en) | 1990-07-09 | 1991-07-08 | Low gloss polyacetal resin composition and molded article |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP2818475B2 (en) |
| KR (1) | KR950006139B1 (en) |
| BR (1) | BR9102880A (en) |
| CA (1) | CA2046469A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115181223A (en) * | 2022-08-15 | 2022-10-14 | 铨盛聚碳科技股份有限公司 | Low-gloss matte auxiliary agent, preparation method thereof and formed body |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002138186A (en) * | 2000-08-24 | 2002-05-14 | Mitsubishi Engineering Plastics Corp | Polyacetal resin composition and molding |
| KR101964094B1 (en) * | 2014-09-30 | 2019-04-02 | (주)엘지하우시스 | Matt coating composition, matt coating sheet and the manufacturing method of the same |
| JP6938267B2 (en) * | 2017-08-03 | 2021-09-22 | 旭化成株式会社 | Polyoxymethylene resin composition |
| JP6938266B2 (en) * | 2017-08-03 | 2021-09-22 | 旭化成株式会社 | Polyoxymethylene resin composition and molded article |
-
1990
- 1990-07-09 JP JP2181117A patent/JP2818475B2/en not_active Expired - Lifetime
-
1991
- 1991-07-08 CA CA002046469A patent/CA2046469A1/en not_active Abandoned
- 1991-07-09 KR KR1019910011628A patent/KR950006139B1/en not_active IP Right Cessation
- 1991-07-09 BR BR919102880A patent/BR9102880A/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115181223A (en) * | 2022-08-15 | 2022-10-14 | 铨盛聚碳科技股份有限公司 | Low-gloss matte auxiliary agent, preparation method thereof and formed body |
| CN115181223B (en) * | 2022-08-15 | 2023-08-29 | 铨盛聚碳科技股份有限公司 | Low-gloss matte auxiliary agent, preparation method thereof and molded body |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0468048A (en) | 1992-03-03 |
| BR9102880A (en) | 1992-02-11 |
| KR950006139B1 (en) | 1995-06-09 |
| KR920002694A (en) | 1992-02-28 |
| JP2818475B2 (en) | 1998-10-30 |
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