JPH0912733A - Fixing chassis of optical writing unit - Google Patents

Abstract

PURPOSE: To obtain the subject chassis excellent in dimensional stability (low in warpage), high in rigidity and good in appearance, useful for laser beam printers, copiers, etc., by molding a resin composition comprising a thermoplastic resin and a mica-contg. filler. CONSTITUTION: This chassis is obtained by molding a resin composition comprising (A) 70-30wt.% of a thermoplastic resin such as an aromatic polycarbonate resin, a graft copolymer obtained by grafting an aromatic vinyl compound and a vinyl cyanide compound to a diene rubber component, or polyester resin and (B) 30-70wt.% of a filler containing >=60wt.% of mica 10-100μm in average particle size and 0.01-1μm in thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical writing unit fixed chassis. More specifically, a laser beam printer (LBP), a copying machine, a facsimile machine, which has excellent dimensional stability (low warpage), high rigidity, and good appearance,
The present invention relates to a chassis for fixing an optical writing unit such as an image processing device (image scanner), a barcode scanner and a plate making machine. The optical writing unit of the laser optical system has a complicated optical path for focusing the laser beam on the surface of the photosensitive drum or at the correct position of the reading device. The optical writing unit fixing chassis referred to here has a role of fixing various components (mirror, lens, scanner motor, etc.) necessary on this optical path.

[0002]

2. Description of the Related Art Thermoplastic resins have excellent productivity in simple melt processing methods such as injection molding and are used in a wide range of industrial fields. Further, a composition obtained by blending a thermoplastic resin with a fibrous filler such as glass fiber or carbon fiber is widely used in a field requiring high rigidity.

However, when a fibrous filler is blended with a thermoplastic resin, there is a drawback that the anisotropy of molding shrinkage increases. When a fibrous filler is added to a thermoplastic resin, the molding shrinkage decreases in the resin flow direction during molding, but in the orthogonal direction, even if the filling amount of the fibrous filler is increased, it does not decrease and warps the molded product. Occurs,
It is not practical for an optical writing unit fixed chassis that requires high dimensional stability in addition to high rigidity. From this point of view, there has been proposed a method of blending a thermoplastic resin with a filler such as glass powder, glass beads, glass flakes, or the like in a short fiber shape, a spherical shape, or a plate shape. However, this method satisfies high dimensional stability, but has low rigidity and is not practical for optical writing unit fixed chassis applications.

In addition, fibrous fillers and short fibrous, spherical,
A method of using together with a plate-like filler has been proposed. Japanese Patent Publication No. 2-54382 discloses a composition containing a polyalkylene terephthalate resin, a polycarbonate resin, a fibrous filler and a plate-like filler. Further, Japanese Patent Publication No. 4-1028 discloses a resin composition comprising a resin containing polybutylene terephthalate as a main component, a fibrous reinforcing agent and a plate reinforcing agent. All of them satisfy high rigidity and high dimensional stability to some extent. However, these publications do not teach the use of these resin compositions for optical writing unit fixed chassis applications. Moreover, when this resin composition was used for the optical writing unit fixed chassis, it was still unsatisfactory.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical writing unit fixed chassis which has excellent dimensional stability, high rigidity and good appearance. As a result of earnest studies by the inventor of the present invention, a resin composition obtained by mixing a thermoplastic resin with mica of a specific shape has excellent dimensional stability, high rigidity, and good appearance, and thus an optical writing unit. The present invention has been achieved by finding that it is suitable as a fixed chassis.

[0006]

That is, according to the present invention, (a) 70 to 30% by weight of a thermoplastic resin (a component) and (b) an average particle size of 10 to 100 μm and a thickness of 0.
Provided is a chassis for fixing an optical writing unit, which is made of a resin composition substantially consisting of a proportion of 30 to 70% by weight of a filler (component b) containing at least 60% by weight of mica having a diameter of 0 to 1 μm.

In the present invention, the thermoplastic resin used as the component a may be a resin which is usually used for obtaining a molded product. Examples of the thermoplastic resin include general-purpose resins such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, ABS resin and AS resin;
General-purpose engineering resins such as polycarbonate, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether and polyamide; high levels of polyphenylene sulfide, polysulfone, polyether sulfone, polyether-ether ketone, polyarylate, aromatic polyester and aromatic polyamide Performance engineering resin; special resins such as fluororesin, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polymethylmethacrylate and polycellulose acetate, etc., and these may be used alone or in admixture of two or more. Can be used.

On the other hand, in the present invention, as the filler of the component b, mica having a specific property is 60% by weight or more, preferably 7% by weight.
Those containing 0% by weight or more are used. This mica is a ground product of a silicate mineral containing aluminum, potassium, magnesium, sodium or iron. It is desirable that the filler of component b substantially consists of this mica. The average particle size of the mica is 10
To 100 μm, and preferably 20 to 50 μm. The average particle size here is a value measured by the Microtrack laser diffraction method. If the average particle size of mica is less than 10 μm, the rigidity is not sufficiently improved,
If it exceeds m, mica is cracked at the stage of melt processing and further improvement in rigidity is not recognized, which is not suitable.

The thickness of the mica is 0.01 to 1 μm.
And a range of 0.03 to 0.9 μm is preferable.
This thickness is a value measured by observation with an electron microscope.
If the thickness of the mica is less than 0.01 μm, the mica is likely to crack at the stage of melt processing, and further improvement in rigidity is not recognized. If it exceeds 1 μm, the rigidity is not sufficiently improved, which is not preferable.

The mica includes muscovite, phlogopite, biotite, artificial mica, etc., and any mica can be used as the component (b) of the present invention, and among them, muscovite is preferable. Phlogopite,
Biotite and artificial mica are more flexible than muscovite themselves, and iron is contained in the main component in a large amount, which is not preferable because the hue itself becomes dark.

Further, in the production of the mica, as a pulverization method, a dry pulverization method of pulverizing a mica rough stone by a dry pulverizer and a coarse pulverization of the mica rough stone by a dry pulverizer, and then adding water to obtain a slurry state After that, there is a wet pulverization method of performing main pulverization with a wet pulverizer, and then performing dehydration and drying. The dry pulverization method is economically advantageous and general, but it is difficult to pulverize mica thinly and finely. Therefore, in the present invention, it is preferable to employ a wet pulverization method which is a production method that easily satisfies the average particle size and thickness of the mica used.

Further, such mica may be surface-treated with a silane coupling agent or the like, or may be granulated with a binder to form a granule. As a commercial product of the mica,
For example, there are mica powder A-41 (manufactured by Yamaguchi Mica Industry Co., Ltd.) and the like, which are easily available on the market.

The blending ratio of the filler (b component) is 30 to 70% by weight, and 40 to 40% by weight based on 100% by weight of the resin composition comprising the thermoplastic resin (a component) and the filler (b component). 60% by weight is preferable, and 40 to 50% by weight is more preferable. If the blending ratio of the filler is less than 30% by weight, the rigidity is not sufficiently improved, and if it exceeds 70% by weight, the moldability of the resin composition is significantly deteriorated, which is not preferable.

Further, as long as the filler as a chassis for fixing the optical writing unit satisfies its rigidity, dimensional stability and the like, 60% by weight or more thereof should be the above-mentioned mica,
Other fillers may be used for less than 40% by weight. When using other fillers, it is preferably 1 to 35% by weight, more preferably 5 to 30% by weight. The fillers referred to here are roughly classified into fibrous fillers, short fibrous fillers, plate-like fillers and spherical fillers.

The fibrous filler has an aspect ratio of 3 or more, and examples of the fibrous filler include glass fiber, carbon fiber, silicon carbide, yellow steel fiber, stainless fiber, potassium titanate or aluminum borate. Or there are whiskers, aromatic polyamide fibers, etc.,
Of these, glass fibers or carbon fibers are preferable, and the glass fibers are amino-based silane coupling agents and / or
It is more preferable that the surface treatment is performed with an epoxy-based silane coupling agent and that the resin is bundled with an epoxy resin and / or a urethane resin.

Examples of the short fibrous filler include glass powder. The plate-like filler has an average particle size of 40μ.
m or more and a thickness of 0.1 to 10 μm is desirable,
Examples of the plate-like filler include talc, glass flakes, metal foils, etc., among which glass flakes are preferable. Examples of the spherical filler include glass beads and glass balloons.

In the present invention, the above-mentioned thermoplastic resin (a component) is, among others, (A) an aromatic polycarbonate resin, (B) a diene rubber component and a graft copolymer obtained by grafting an aromatic vinyl compound and a vinyl cyanide compound. , (C) polyester resin and (D) polyphenylene ether-based resin, at least one thermoplastic resin selected from at least 50% by weight based on the total weight of the component a.
At least one selected from the group consisting of (A) an aromatic polycarbonate resin, (B) a graft copolymer obtained by grafting an aromatic vinyl compound and a vinyl cyanide compound on a diene rubber component, and (D) a polyphenylene ether resin. It is more preferable that one amorphous thermoplastic resin is contained in at least 50% by weight based on the total weight of the component a. Amorphous thermoplastic resins are preferably used because they have a smaller molding shrinkage than crystalline thermoplastic resins, and there is no distortion or warpage due to crystal orientation, and no dimensional change due to recrystallization after molding, and superior dimensional stability. To be

The aromatic polycarbonate resin used in the present invention is a resin usually used as an engineering resin, and is an aromatic polycarbonate resin obtained by reacting a dihydric phenol and a carbonate precursor. Typical examples of the dihydric phenol used here include 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A), bis (4-hydroxyphenyl) methane, and 1,1-bis (4 -Hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-)
3,5-Dimethylphenyl) propane, 2,2-bis (4
-Hydroxy-3,5-dibromophenyl) propane,
2,2-bis (4-hydroxy-3-methylphenyl)
Propane, bis (4-hydroxyphenyl) ether,
4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone and the like can be mentioned. Preferred dihydric phenols are bis (4-hydroxyphenyl) alkanes, of which bisphenol A is particularly preferred.

As the carbonate precursor, carbonyl halide, carbonate ester, haloformate or the like is used, and specific examples thereof include phosgene, diphenyl carbonate or dihaloformate of dihydric phenol.

In producing the aromatic polycarbonate resin by reacting the above dihydric phenol with the carbonate precursor, the dihydric phenol can be used alone or in combination of two or more kinds, and the aromatic polycarbonate resin is trifunctional or more than trifunctional. It may be a branched polycarbonate resin obtained by copolymerizing the polyfunctional aromatic compound described above or a mixture of two or more kinds of aromatic polycarbonate resins. Further, if necessary, a catalyst, a molecular weight modifier, an antioxidant, etc. may be used.

Regarding the molecular weight of the aromatic polycarbonate resin, any molecular weight can be used. For example, when an aromatic polycarbonate resin is obtained by using bisphenol A as the dihydric phenol and phosgene as the carbonate precursor, the concentration is 0.7 g / It is preferable that the specific viscosity (η _sp ) measured with a dl methylene chloride solution at a temperature of 20 ° C. is 0.15 to 1.5.

The graft copolymer used in the present invention is a copolymer having a diene rubber component as a backbone and an aromatic vinyl compound component and a vinyl cyanide compound component graft-polymerized thereto. Examples of the diene rubber component include polybutadiene, polyisoprene and styrene-
Butadiene copolymers and the like are mentioned, and among them, polybutadiene is preferably used. Examples of the aromatic vinyl compound component grafted to these diene rubber components include styrene, α-methylstyrene, p-methylstyrene, alkoxystyrene and halogenated styrene, and among them, styrene is preferably used. Examples of the vinyl cyanide compound component include acrylonitrile, methacrylonitrile, chloroacrylonitrile, and the like, of which acrylonitrile is preferably used. Furthermore, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate and the like can be used. Among these graft copolymers, AB
S resin is preferably used.

These graft copolymers include bulk polymerization,
It may be produced by any of polymerization methods such as solution polymerization, suspension polymerization and emulsion polymerization, and the grafting method may be one-step grafting or multi-step grafting. Further, the graft copolymer can be used not only as one type but also as a mixture of two or more types.

The polyester resin used in the present invention is a resin obtained by a polycondensation reaction between a dicarboxylic acid component and a glycol component. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2,5-dichloroterephthalic acid, 2-methylterephthalic acid, 4,4-stilbenedicarboxylic acid, 4,
4-biphenyldicarboxylic acid, orthophthalic acid, 2,6
-Naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-
(Carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4-diphenyl ether carboxylic acid, 4,4-diphenoxyethane dicarboxylic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid and 1, 4-cyclohexanedicarboxylic acid and the like can be mentioned, and these can be used alone or in combination of two or more kinds. Among these dicarboxylic acid components, terephthalic acid and isophthalic acid are preferably used alone or as a mixture thereof.

Examples of the glycol component include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, trans- or cis-2,2,4, 4-Tetramethyl-1,3-cyclobutanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexane Examples include dimethanol, decamethylene glycol, cyclohexanediol, p-xylene diol, 2,2-bis (4-hydroxyphenyl) propane and 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane. These may be used alone or in combination of two or more. Among these glycol components, ethylene glycol and 1,4-butanediol are preferably used.

Specific examples of these polyester resins include polyethylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polycyclohexane dimethylene terephthalate, poly (ethylene terephthalate / cyclohexane dimethylene terephthalate) copolymer. , Poly (ethylene terephthalate / ethylene isophthalate) copolymer, poly (butylene terephthalate / butylene dodecadioate) polyester ether copolymer, polyarylate, and the like. These polyester resins may be used alone or in combination of two or more. May be used. Among these polyester resins, polyethylene terephthalate resin or polybutylene terephthalate resin is preferably used.

The polyphenylene ether resin used in the present invention is polyphenylene ether,
A modified polyphenylene ether obtained by blending the copolymer and another resin.

Examples of the polyphenylene ether include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether) and poly (2-methyl-6). -Phenyl-
1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene ether) and 2,6-dimethylphenol and other phenols (eg 2,3,6-trimethylphenol and 2-methyl-phenol). 6-butylphenol) and copolymers, among which poly (2,6)
-Dimethyl-1,4-phenylene ether) or 2,6
A copolymer of -dimethylphenol and 2,3,6-trimethylphenol is preferable, and poly (2,6-dimethyl-
1,4-phenylene ether) is more preferable. Also,
The polyphenylene ether and the α, β-unsaturated carboxylic acid or its derivative are preferably used in the molten state, dissolved state or slurry state in the presence of a radical generator.
Polyphenylene ether obtained by reacting at a temperature of 0 to 350 ° C. (0.01 to 10% by weight is α, β
-Unsaturated carboxylic acid or its derivative grafted or added).

Examples of the modified polyphenylene ether blended with another resin include a blend of the above polyphenylene ether and a vinyl aromatic compound polymer, a polyamide resin, or the like. Among them, a vinyl aromatic compound polymer is preferable. Is preferred.

The vinyl aromatic compound polymer is a vinyl aromatic compound polymer or a vinyl aromatic compound-conjugated diene compound copolymer, and examples of the vinyl aromatic compound polymer are styrene and α-methylstyrene. , Α-ethyl styrene, o-methyl styrene, m-methyl styrene and nuclear alkyl-substituted styrenes such as p-methyl styrene or o-chloro styrene, m-chloro styrene, p-
Examples thereof include polymers of nuclear halogenated styrenes such as chlorostyrene, p-bromostyrene, dichlorostyrene, dibromostyrene, trichlorostyrene and tribromostyrene. Among them, polymers of styrene or α-methylstyrene are preferable. . Examples of vinyl aromatic compound-conjugated diene compound copolymer include styrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer and methyl methacrylate-butadiene-styrene copolymer. Among these, styrene
Butadiene copolymers are preferred.

The polyphenylene ether resin was prepared by dissolving 0.5 g of this resin in 100 ml of chloroform,
The reduced viscosity measured at 0 ° C. is preferably in the range of 0.15 to 0.7.

A more preferable embodiment of the thermoplastic resin (component a) is that (1) an aromatic epoxy resin or phenoxy resin is contained in an amount of 0 to 20% by weight and an epoxy silane coupling agent is included in an amount of 0 to 5% by weight. Good aromatic polycarbonate resin (a-1 component), (2) 10 to 99% by weight of aromatic polycarbonate resin, 1 to 90% by weight of a graft copolymer obtained by grafting a diene rubber component with an aromatic vinyl compound and a vinyl cyanide compound, A mixture of 0 to 20% by weight of an aromatic epoxy resin or a phenoxy resin and 0 to 5% by weight of an epoxy silane coupling agent (a-2 component), (3) an aromatic polycarbonate resin 6
0 to 99% by weight, aromatic polyester resin 1 to 40% by weight, aromatic epoxy resin or phenoxy resin 0 to 2
0 wt% and epoxy silane coupling agent 0-5
A polyphenylene ether system which may contain 0 to 20% by weight of a mixture (a-3 component) or (4) an aromatic epoxy resin or a phenoxy resin, and 0 to 5% by weight of an epoxy silane coupling agent. Resin (a
-4 component). In particular, the a-1 component, the a-2 component and the a-3 component generate less gas during molding than the a-4 component and are excellent in mold fouling property, and therefore are preferably used.

As the component a-1, an aromatic polycarbonate resin capable of containing 20 wt% or less of an aromatic epoxy resin or phenoxy resin and 5 wt% or less of an epoxy silane coupling agent is used. As this aromatic polycarbonate resin, the same one as described above for the aromatic polycarbonate resin is used.

The aromatic epoxy resin or phenoxy resin is preferably used because it has the effect of further increasing the thermal stability of the aromatic polycarbonate resin during melt processing. The aromatic epoxy resin or phenoxy resin is an epoxy resin or a phenoxy resin synthesized from an aromatic polyol and epihalogenohydrin, preferably an epoxy resin or a phenoxy resin synthesized from bisphenol A and epichlorohydrin. Commercially available products of epoxy resin include, for example, Epotote YD series (manufactured by Toto Kasei Co., Ltd.), and commercially available products of phenoxy resin include, for example, Fenototo (manufactured by Toto Kasei Co., Ltd.) and the like. Easily available at. The compounding ratio of this aromatic epoxy resin or phenoxy resin is a-
20% by weight or less in one component, preferably 0.5 to 1
0% by weight. If the blending ratio exceeds 20% by weight, the molding processability of the composition is significantly deteriorated, which is not preferable.

The epoxy silane coupling agent is preferably used because it has the effect of further enhancing the thermal stability of the aromatic polycarbonate resin during melt processing. This epoxy-based silane coupling agent has the following general formula (1)

[0036]

Embedded image

Wherein R ¹ is a methyl group or an ethyl group, R ² is an alkyl group having 1 to 3 carbon atoms, R ³ is a γ-glycidoxypropyl group or β-
(3,4-epoxycyclohexyl) ethyl group, m + n
= 3, m = 1 or 0, and n = 2 or 3. Among the epoxy-based silane coupling agents represented by the general formula (1), particularly preferred are β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-. Examples thereof include glycidoxypropylmethyldiethoxysilane. These may be used alone or in combination of two or more.

The mixing ratio of this epoxy silane coupling agent is 5% by weight or less, preferably 0.1 to 2% by weight in the component a-1. If the blending ratio exceeds 5% by weight, the molding processability of the composition is significantly reduced, which is not preferable.

Further, the effect of heat stability can be further enhanced by using the above-mentioned aromatic epoxy resin or phenoxy resin and the epoxy silane coupling agent in combination.

As the component a-2, 10 to 99% by weight of an aromatic polycarbonate resin, 1 to 90% by weight of a graft copolymer obtained by grafting an aromatic vinyl compound and a vinyl cyanide compound on a diene rubber component, an aromatic epoxy resin or A mixture of 0 to 20% by weight of a phenoxy resin and 0 to 5% by weight of an epoxy-based silane coupling agent is used.

The same aromatic polycarbonate resin as described above is used, and the compounding ratio thereof is 10 to 99% by weight in the component a-2, preferably 30 to 95% by weight, and 60 to 90% by weight. Is more preferable. As the graft copolymer obtained by grafting the aromatic vinyl compound and the vinyl cyanide compound to the diene rubber component, the same one as described above is used, and the blending ratio thereof is 1 to 90 in the component a-2.
% By weight, preferably 5 to 70% by weight, 10 to 40
% Is more preferred.

As the aromatic epoxy resin or phenoxy resin, the same ones as described above are used, which has the effect of further increasing the thermal stability of the component a-2, and the mixing ratio thereof is 20% by weight in the component a-2. % Or less, preferably 0.5
10 to 10% by weight. The same epoxy silane coupling agent as described above is used, and it has an effect of further increasing the thermal stability of the component a-2, and the compounding ratio thereof is a-
It is 5% by weight or less, and preferably 0.1 to 2% by weight in the two components.

As component a-3, aromatic polycarbonate resin 60 to 99% by weight, aromatic polyester resin 1 to 40% by weight, aromatic epoxy resin or phenoxy resin 0 to 20% by weight, and epoxy type silane coupling agent. Mixtures of 0-5% by weight are used.

As this aromatic polycarbonate resin, the same one as described above is used, and the mixing ratio thereof is a-3.
The content is 60 to 99% by weight, preferably 70 to 95% by weight. As the aromatic polyester resin, the same ones as described above are used except that either the dicarboxylic acid component or the glycol component has an aromatic group, and the mixing ratio thereof is 1 to 40% by weight in the a-3 component. And 5 to 3
0% by weight is preferred.

As the aromatic epoxy resin or phenoxy resin, the same ones as described above are used, which has the effect of further increasing the thermal stability of the a-3 component, and the mixing ratio thereof is 20% by weight in the a-3 component. % Or less, preferably 0.5
10 to 10% by weight. As the epoxy silane coupling agent, the same one as described above is used, and it has an effect of further enhancing the thermal stability of the component a-3.
It is 5% by weight or less, preferably 0.1 to 2% by weight in the three components.

Further, as the component a-4, a polyphenylene ether resin which can contain 20% by weight or less of an aromatic epoxy resin or a phenoxy resin and 5% by weight or less of an epoxy silane coupling agent is used. As this polyphenylene ether-based resin, the same one as described above for the polyphenylene ether-based resin is used.

As the aromatic epoxy resin or phenoxy resin, the same one as described above is used, and it has the effect of further increasing the thermal stability of the component a-4, and the mixing ratio thereof is a.
-20% by weight or less in 4 components, preferably 0.5-
10% by weight. As the epoxy silane coupling agent, the same one as described above is used, and it has an effect of further increasing the thermal stability of the component a-4, and its compounding ratio is a-
It is 5% by weight or less, preferably 0.1 to 2% by weight in the four components.

Further, it is preferable to add a flame retardant to the resin composition comprising the thermoplastic resin (a component) and the filler (b component). The optical writing unit fixed chassis is often required to have flame retardancy, and a flame retardant is blended to satisfy this requirement. Examples of the flame retardant include brominated bisphenol, brominated epoxy resin, brominated polystyrene, brominated polycarbonate, triphenyl phosphate, phosphonic acid amide and red phosphorus. Among them, triphenyl phosphate or brominated polycarbonate, in particular, Tetrabrom bisphenol A
A polycarbonate oligomer having a specific viscosity of 0.02 to 0.2 obtained is more preferable. Further, addition of the triphenyl phosphate or the brominated polycarbonate oligomer to the above resin composition not only imparts flame retardancy but also enhances rigidity, and is preferably used. The blending amount thereof is preferably 1 to 20% by weight, more preferably 3 to 15 parts by weight, based on 100 parts by weight of the resin composition. If it exceeds 20 parts by weight, the heat resistance and impact resistance are remarkably reduced, which is not preferable.

Further, an elastic polymer may be added to the resin composition. The addition of an elastic polymer is preferably used because the impact strength of such a resin composition is improved. Examples of the elastic polymer include butadiene-alkyl methacrylate-styrene copolymer, butadiene-alkyl methacrylate-styrene-divinylbenzene copolymer and butadiene-alkyl acrylate-
Examples include acrylic elastic polymers such as alkyl methacrylate copolymers, and composite elastic polymers having a structure in which a polyorganosiloxane rubber and a polyalkyl (meth) acrylate rubber component are intertwined with each other. Alternatively, two or more kinds can be mixed and used. The compounding amount of the elastic polymer is 1 with respect to 100 parts by weight of the resin composition.
-20 parts by weight is preferable, and 3-15 parts by weight is more preferable. If it exceeds 20 parts by weight, the rigidity is lowered, which is not preferable.

The resin composition of the present invention contains a flame retardant aid (eg, antimony trioxide, sodium antimonate, etc.), a nucleating agent (eg, sodium stearate, ethylene-acrylic acid) to the extent that the object of the present invention is not impaired. Sodium copolymer, etc.), stabilizer (for example, phosphoric acid ester, phosphite ester, etc.), antioxidant (for example, hindered phenol compound, etc.), light stabilizer, colorant, foaming agent, lubricant, release agent , An antistatic agent or the like may be blended, and a small amount of rubber or the like may be added.

The optical writing unit fixing chassis of the present invention preferably has a bending elastic modulus of 9,800 MPa or more. Bending elastic modulus here means AST
It is a value measured according to MD-790 and is a value indicating the degree of rigidity. Since the optical writing unit fixed chassis is required to have high rigidity, it is desirable that the bending elastic modulus is 9,800 MPa or more as described above.

The optical writing unit fixing chassis of the present invention preferably has a warpage rate of 2.0% or less, and 1.5.
% Or less is more preferable. The warpage rate here is based on JIS
Measured according to K6911 and is a measure of dimensional stability. Further, the twist rate is preferably 4.0% or less, more preferably 2.0% or less. The twist ratio here is measured according to JIS K6911,
It is a measure of dimensional stability. Since the optical writing unit fixed chassis is required to have high dimensional stability, it is desirable that the warp rate is 2.0% or less and the twist rate is 4.0% or less.

Any method can be adopted to manufacture the optical writing unit fixing chassis of the present invention. For example, a thermoplastic resin, mica, and other additives as appropriate are thoroughly mixed using a mixing means such as a V-type blender, and then pelletized by a bend type uniaxial ruder, and the pellets are injection molded to form an optical writing unit. A method generally used in industry such as a method for manufacturing a fixed chassis is appropriately used.

[0054]

【Example】

Examples 1 to 11 and Comparative Examples 1 to 10 Examples will be further described below, but the present invention is not limited thereto. The thermoplastic resins, fillers and other additives described in Tables 1 and 2 were mixed in a tumbler at the ratios shown in Tables 1 and 2, and the mixture was mixed with a uniaxial ruder (VSK-30, Nakatani Machine Co., Ltd.) having a diameter of 30 mm. ,
Pellets were obtained by extruding at a cylinder temperature of 260 to 290 ° C. The obtained pellets were dried at 105 ° C. for 5 hours with a hot air circulation dryer, and then the cylinder temperature was 270 with an injection molding machine (Sumitomo Heavy Industries, Ltd. SG-150U).
-300 ° C, mold temperature 60 to 100 ° C Bending elastic modulus measuring test piece Bending elastic modulus measuring test piece and flat plate molding die 150 mm x 150 mm x 1.5 m
mt. A flat plate molded product of Next, the bending elastic modulus was measured by using the bending elastic modulus test piece, and the warpage rate and the twist rate were measured by using a flat plate molded article by the methods shown in the following (1) to (2). The evaluation results are shown in Tables 1 and 2.

(1) Flexural modulus (MPa): ASTM
It was measured according to D-790. (2) Warp rate and twist rate: Measured according to JIS K6911. The symbols showing the components shown in Tables 1 and 2 are as follows. (A) PC: aromatic polycarbonate resin (aromatic polycarbonate resin synthesized from bisphenol A and having a specific viscosity of 0.42; Panlite L-1 manufactured by Teijin Chemicals Ltd.)
225) (B) ABS: acrylonitrile-butadiene-styrene copolymer (UT-61 manufactured by Mitsui Toatsu Co., Ltd.) (C) PBT: polybutylene terephthalate resin (TRB-H manufactured by Teijin Ltd.) (D) PPE : Polyphenylene ether resin [poly (2,6-dimethyl-1,4-phenylene ether) GE
MPE PPE] (E) PS: Polystyrene resin (Denka Styrol MW manufactured by Denki Kagaku Kogyo Co., Ltd.) (F) M-1: Mica (average particle size by microtrack laser diffraction method is 39.97 μm, electron microscope Mica having a thickness of 0.03 to 0.3 μm observed by Mica Co., Ltd. (Yamaguchi Mica Industry Co., Ltd., mica powder A-41) (G) M-2: mica (average particle size by microtrack laser diffraction method is 5 Mica having a particle size of .18 μm and a thickness of 0.03 to 0.3 μm observed by an electron microscope, Mica powder A-11 manufactured by Yamaguchi Mica Industry Co., Ltd. (H) GFL: glass flakes (average particle size 600 μm,
Glass flakes with a thickness of 5 μm R manufactured by Nippon Sheet Glass Co., Ltd.
EFG-101) (I) CS: glass fiber (fiber diameter 13 μm, cut length 3)
mm glass fiber T-511 manufactured by Nippon Sheet Glass Co., Ltd. (J) CF: carbon fiber (fiber diameter 7 μm, cut length 6 mm)
Carbon fiber manufactured by Toho Rayon Co., Ltd. HTA-C-6
U) (K) PR: Aromatic phenoxy resin (polymer obtained from bisphenol A and epichlorohydrin, hydroxyl group equivalent 0.35 eq / 100 g Tonoto Kasei Co., Ltd. Phenototo YP-50) (L) SI: Epoxy silane cup Ring agent (γ-glycidoxypropyltrimethoxysilane, KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) (M) FR: Flame retardant (polycarbonate oligomer obtained from tetrabromobisphenol A, manufactured by Teijin Chemicals, Ltd., Fireguard FG) -7000) (N) TPP: flame retardant (triphenyl phosphate TPP manufactured by Daihachi Chemical Co., Ltd.)

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

EFFECT OF THE INVENTION The resin composition substantially composed of the thermoplastic resin of the present invention and the filler containing mica as a main component is excellent in dimensional stability, high in rigidity and good in appearance, so that it is fixed to the optical writing unit. It is suitable for chassis and its industrial effect is exceptional.

Claims (11)

[Claims] 1. A thermoplastic resin (a component) 70 to 3 (a)
30% to 70% by weight of filler (b component) containing 0% by weight and (b) at least 60% by weight of mica having an average particle size of 10 to 100 μm and a thickness of 0.01 to 1 μm.
An optical writing unit fixed chassis formed of a resin composition substantially consisting of 2. The optical writing unit fixing chassis according to claim 1, wherein the proportion of the thermoplastic resin (a component) is 60 to 40% by weight and the filler (b component) is 40 to 60% by weight. 3. The optical writing unit fixing chassis according to claim 1, wherein the mica has an average particle size of 20 to 50 μm and a thickness of 0.03 to 0.9 μm. 4. The optical writing unit fixed chassis according to claim 1, wherein the mica is mica obtained from muscovite as a raw material. 5. The optical writing unit fixed chassis according to claim 1, wherein the filler (b component) contains at least 70% by weight of the mica. 6. The thermoplastic resin (component a) is (A) an aromatic polycarbonate resin, (B) a diene rubber component grafted copolymer with an aromatic vinyl compound and a vinyl cyanide compound, and (C) a polyester. 2. The optical writing unit fixed chassis according to claim 1, which contains at least 50% by weight of the resin and at least one thermoplastic resin selected from (D) polyphenylene ether-based resin with respect to the total weight of the component a. 7. The thermoplastic resin (a component) may contain (1) 0 to 20% by weight of an aromatic epoxy resin or a phenoxy resin and 0 to 5% by weight of an epoxy silane coupling agent. Aromatic polycarbonate resin (a
-1 component), (2) aromatic polycarbonate resin 10
99% by weight, 1 to 90% by weight of a graft copolymer obtained by grafting an aromatic vinyl compound and a vinyl cyanide compound on a diene rubber component, 0 to 20% by weight of an aromatic epoxy resin or phenoxy resin, and an epoxy silane coupling agent 0 A mixture consisting of 5 wt% (component a-2),
(3) 60 to 99% by weight of aromatic polycarbonate resin,
A mixture (a-3 component) or (4) aromatic comprising 1 to 40% by weight of aromatic polyester resin, 0 to 20% by weight of aromatic epoxy resin or phenoxy resin, and 0 to 5% by weight of epoxy silane coupling agent. The optical writing unit according to claim 1, which is a polyphenylene ether resin (a-4 component) which may contain 0 to 20% by weight of an epoxy resin or a phenoxy resin and 0 to 5% by weight of an epoxy silane coupling agent. Fixed chassis. 8. The thermoplastic resin (a component) is the a-
The optical writing unit fixed chassis according to claim 1, wherein the chassis is a single component, a-2 component, or a-3 component. 9. The optical writing unit fixed chassis according to claim 1, which has a bending elastic modulus of 9,800 MPa or more. 10. The warpage rate is 2.0% or less.
Fixed optical writing unit chassis. 11. The optical writing unit fixed chassis according to claim 1, wherein the twist ratio is 4.0% or less.