JPH107879A - Abrasion-resistant resin composition and coating composition for electrophotographic photosensitizer and charge transfer layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject inexpensive composition comprising a styrene- butadiene block copolymer and a specific copolymer, capable of being dissolved in general solvents such as toluene, excellent in abrasion resistance and suitable for charge transfer layers for electrophotographic photosensitizers, etc. SOLUTION: This abrasion-resistant resin composition comprises (A) 99-30wt.% of a styrene-butadiene block copolymer comprising (i) a polymer block consisting mainly of a vinyl aromatic hydrocarbon in an amount of 60-90wt.% and (ii) a polymer block consisting mainly of a conjugated diolefin in an amount of 40-10wt.%, and (B) 1-70wt.% of a styrene-methacrylate copolymer having a Taber abrasion loss of <20mg measured by JIS K-7204 and satisfying the inequality: 1.3<(0.0515Y+X)<1.5 (X is a reduced viscosity (dl/g); Y is a methacrylate ester content (%); 5<Y<18; 0.5<X<1.1). The component A is preferably a radially branched block copolymer of the formula: (A-B)n Z [A is the component (i); B is the component (ii); Z is the residue of a multifunctional coupling agent].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abrasion-resistant styrenic resin composition, and more particularly to a coating composition for an electrophotographic photosensitive member using the same as a binder, and a charge transport layer and / or a protective layer.

[0002]

2. Description of the Related Art Styrene resins are widely used in the field of light electric appliances, machine parts, miscellaneous goods, etc. because they have both good moldability and transparency, and impart impact resistance by being modified with rubber. However, when using styrene-based resin for sliding parts with friction or wear, a part of the resin is deformed or scraped due to its low abrasion resistance, making full use of the inherent properties of the resin. There was a drawback that it could not be used in the field.

Attempts have been made to improve abrasion resistance by adding additives such as polydimethylsiloxane. However, according to this method, transparency is impaired probably because of a problem with compatibility with styrene resins. Not only can it not be used especially in areas where transparency is required, but also because of the bleed-out of polydimethylsiloxane on the molded product surface, causing mold contamination during molding, and the high price of additives The problem was that the cost was increased.

[0004] One of the uses of the transparent resin is as a binder resin for an electrophotographic photosensitive member. In this method, an appropriate viscosity is adjusted by utilizing the solubility of a resin in a solvent, and an organic pigment or a functional organic pigment is dispersed therein and applied to a substrate. When an electrophotographic photoreceptor using this binder resin is applied to a copying process or a printing process, processes such as charging, exposure, development, transfer, static elimination and cleaning are repeatedly performed, so that a charge transport layer (protection) on the photoreceptor surface is protected. The binder resin used for the layer) is required to be particularly excellent in transparency and abrasion resistance. With the recent increase in the performance and speed of copying machines, there has been an increasing demand for resin compositions having even better abrasion resistance.

In general, a technique for improving abrasion resistance and printability by using a polycarbonate-based material as a binder resin for a charge transport layer of an electrophotographic photosensitive member has been proposed (JP-A-6-266143, JP-A-6-332234
issue). However, since the resin as described above needs to be dissolved in a halogen-based special solvent such as dichloromethane, which has good abrasion resistance but is highly toxic, a binder resin that is soluble in a general aromatic solvent such as toluene has been desired. .

Japanese Patent Application Laid-Open No. 2-158746 discloses an electrophotographic photosensitive member in which a charge generation layer (photosensitive layer) and a charge transport layer (protective layer) are sequentially provided on a conductive substrate. Layer) contains at least one binder selected from a polyarylate resin, a polysulfone resin, a styrene-acrylonitrile copolymer and a styrene-butadiene copolymer, and metal oxide fine powder, and a developer such as a toner adheres to the surface. An electrophotographic photoreceptor that provides a clear copy screen has been proposed. However, also in this case, the abrasion resistance to the repeated copying process was not sufficient.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a styrene-based resin composition which is soluble in general aromatic solvents such as toluene, is inexpensive, and has excellent wear resistance which can be used for sliding parts with wear. And a coating composition for an electrophotographic photoreceptor and a charge transport layer and / or a protective layer.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a specific styrene-butadiene block copolymer and a special styrene-methacrylic acid ester-based copolymer have been identified. The compounded composition is not only a material excellent in abrasion resistance, but also soluble in general aromatic solvents such as toluene, inexpensive, and suitable for a charge transport layer and a protective layer for an electrophotographic photosensitive member. To complete the present invention. That is, the wear-resistant resin composition of the present invention,
The content of the polymer block composed mainly of a vinyl aromatic hydrocarbon 60~90wt%, the content of the polymer block composed mainly of a conjugated diolefin consists 40～10Wt% styrene - butadiene block copolymer (I ) 99-3
A blend resin composition of 0 wt% and 1 to 70 wt% of a styrene-methacrylic ester copolymer (II), wherein the styrene-methacrylic ester copolymer (II) has a reduced viscosity (dl / g) is defined as X and the methacrylate content (wt%) is defined as Y.
1.3 <0.0515Y + X <1.5 is satisfied (provided that 5 <Y <18 and 0.5 <X <1.1), and Taber measured according to JIS K-7204 The wear amount is less than 20 mg.

Further, a coating composition for an electrophotographic photoreceptor of the present invention comprises the above-mentioned abrasion-resistant styrenic resin composition, a solvent and an organic photoconductive material. The transport layer and / or the protective layer is characterized in that an organic photoconductive material is dispersed and contained using the above-mentioned abrasion-resistant styrenic resin composition as a binder.

Hereinafter, the present invention will be described in detail. As the styrene-butadiene block copolymer in the present invention,
At least one selected from linear block copolymers and radially branched block copolymers may be used, but a mixture of two or more types may be used. Here, as the linear block copolymer, general formulas (AB) _n , A- (BA) _n ,
B- (AB) _n (where A is a polymer block mainly composed of vinyl aromatic hydrocarbon, B is a polymer block mainly composed of conjugated diolefin, and n is an integer of 1 or more. (Usually an integer of 1 to 5). Further, as the radially branched block copolymer, a general formula (AB) _n Z (where A and B are the same as described above, but Z is used for forming a radially branched block copolymer) And n represents the number of functional groups of the polyfunctional coupling agent, and is an integer of at least 3).

In these block copolymers, the polymer block A mainly composed of vinyl aromatic hydrocarbon includes styrene, styrene derivatives such as side-chain alkyl-substituted styrene such as α-methylstyrene, and core alkyl such as vinyltoluene. Blocks formed of halogenated styrenes such as substituted styrene and chlorostyrene, divinylbenzene and the like can be raised. The conjugated diene polymer block B is, for example, a copolymer block formed of any of conjugated diene compounds such as butadiene and isoprene. The ratio of A and B is such that the polymer of A is 60 to 60%.
It is a so-called resin-like styrene-butadiene block copolymer having a low rubber component, comprising 90 Wt% and a polymer of B of 40 to 10 Wt%.

The styrene-butadiene block copolymer particularly preferred in the present invention includes the above-mentioned general formula (A-
B) is a radial branched block copolymer represented by _n Z. Examples of the polyfunctional treating agent used for forming the residue Z (s) of the polyfunctional coupling agent of the resin include, for example, polyepoxides, polycisocyanates, polyaldehydes, polyketones, polyamines ,
A center or a central atomic group of a radially branched block copolymer derived from a coupling agent having three or more functionalities such as a tin compound such as tetraallyl tin or stannic fluoride;
n is an integer of at least 3 or more. Specific methods for producing these styrene-butadiene block copolymers include:
JP-B-43-14979, JP-B-48-4106, JP-B-49-86959
An example is described in detail in the issue.

In the present invention, the styrene-methacrylic ester copolymer is obtained by copolymerizing a styrene monomer and a methacrylic ester monomer. Styrene monomers that are constituents thereof include styrene, styrene derivatives such as side-chain alkyl-substituted styrene such as α-methylstyrene, nuclear alkyl-substituted styrene such as vinyltoluene, halogenated styrene such as chlorostyrene, divinylbenzene, etc. Can be raised.

[0014] Examples of the methacrylate-based monomers include, in addition to methyl methacrylate, ethyl methacrylate, propylene methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate,
Alkyl methacrylates such as phenyl methacrylate can be mentioned. Examples of acrylates include methyl acrylate, ethyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, phenyl acrylate, and benzyl acrylate. In particular, the methacrylate content is 5 to 18 wt.
% Is preferred.

In the present invention, the styrene-methacrylic acid ester-based copolymer has a reduced viscosity (dl / g) of X,
When the methacrylate content (Wt%) is Y, the relational expression satisfies 1.3 <0.0515Y + X <1.5 (provided that 5 <Y <18 and 0.5 <X <1. 1). Here, when the reduced viscosity (ηsp / c) X is 0.5 or less, the impact resistance and the abrasion resistance are poor, which is not preferable. Reduced viscosity (ηsp / c)
When X is 1.1 or more, it is not preferable in that a pear-skin pattern such as frosted glass easily occurs on the surface.

The content of methacrylic acid ester (Wt%)
If Y is less than 5% by weight, the impact resistance is impaired, which is not preferable, and the methacrylate content Y is 18% by weight.
If it exceeds, transparency is impaired, and it cannot be used as a binder resin for a charge transport layer of an electrophotographic photoreceptor. Further, when the value of the above relational expression is 1.3 or less, the falling weight impact strength deteriorates, which is not preferable. On the other hand, when the value of the above relational expression is 1.5 or more, it is not preferable because a satin pattern is easily generated, the haze is increased, and the transparency is inferior. In order to satisfy these conditions, the reduced viscosity can be adjusted by changing the polymerization temperature, initiator, chain transfer agent, solvent, and the like. The polymerization method includes bulk polymerization or solution polymerization, but is not particularly limited.

In the present invention, the method of compounding these components is not particularly limited, and a conventionally known melt kneader can be used. For example, a continuous kneader equipped with a twin-screw rotor, an extruder, a calender roll, a Banbury mixer and the like can be mentioned. The styrene resin composition of the obtained blend is J
20 mg of Taber abrasion measured by ISK-7204
Must be less than. This Taber wear amount is 20m
If it is more than g, it is not preferable because the shaved resin is mixed into the product when it is used for a sliding part with friction or wear. Furthermore, tensile strength (σ: kgf / mm unit)
The product (σ · ε) of 2) and elongation (ε: unit%) is preferably 600 or more. If this product (σ · ε) is less than 600, the material will not only be a material having a good balance of mechanical strength and impact resistance, but also will not be able to suppress the Taber abrasion amount to 20 mg or less.

The abrasion-resistant styrenic resin composition of the present invention may optionally contain n-octadecyl 3- (3,5-di-tert-b
uyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-
Hindered phenols such as 4-methylphenol, trisnon
ylphenyl phosphite, tris (2,4-di-tert-butylphenyl) p
Phosphorus such as hosphite, pentaerythrityl tetrakis (3-la
uryl thiopropionate), 2- [1- (2-hydroxy-
3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentyl
A phenol acrylate-based antioxidant such as phenyl acrylate may be added.

The abrasion-resistant styrenic resin composition obtained by the present invention can be used for a sheet, a film, an injection molded product of various shapes, a hollow molded product, a vacuum molded product, etc. by a known molding method. Can be widely used for parts with wear in the miscellaneous goods and mechanical fields. In particular, a coating composition for an electrophotographic photoreceptor utilizing the properties of abrasion resistance,
Further, it is suitable as a charge transport layer and / or a protective layer in which an organic photoconductive material is dispersed and contained as a binder resin. Hereinafter, a case where the charge transport layer (protective layer) of the electrophotographic photosensitive member is used will be described. The charge transport layer and / or the protective layer are formed together with the charge generation layer on the conductive substrate and become a part of the electrophotographic photosensitive member.

Here, the electrophotographic photoreceptor has a charge generation layer in which a photoconductive material such as a phthalocyanine pigment which generates a charge by specific light is formed on a conductive substrate with a resin binder, and further on the charge generation layer. And a charge transport layer formed thereon, and may be further provided with a protective layer. The charge transport layer is formed of a binder containing an organic photoconductive material such as a hydrazone compound so as to carry the charge generated in the charge generation layer to the outermost layer of the electrophotographic photosensitive member. The copy process called the Carlson process is composed of charge-exposure-development-transfer-static elimination / cleaning. Since the copy process is performed in one cycle, the conductive substrate (usually metal) has a cylindrical drum shape. .

The performance of a copying machine is affected by its copy resolution and the number of copies per minute. The higher the performance, the shorter the time required for the copying process per cycle. Accordingly, the drum-shaped conductive substrate is forced to rotate at high speed, and is required to have wear resistance. The improvement in the wear resistance of the charge transport layer and the protective layer largely depends on the resin binder, and thus, in addition to compatibility with the organic photoconductive material as the charge transport substance, film forming properties and wear resistance are required. Therefore, in the present invention, the above-mentioned abrasion-resistant styrene-based resin composition is used as a resin binder for a charge transport layer (protective layer).

When the abrasion-resistant material of the present invention is used as a charge transport layer in an electrophotographic photoreceptor, the conductive substrate includes
There is no particular limitation, and a commonly used metal plate such as aluminum, a metal drum, a plastic film in which aluminum foil is laminated, or the like can be appropriately used. The charge generation layer formed on the conductive substrate is generally formed from a binder resin and an organic photoconductive material which is a charge generation substance. The binder resin used for the charge generation layer includes, but is not particularly limited to, polycarbonate resins, polystyrene resins, polyester resins, methacrylate resins, acrylate resins, and the like.

Examples of the charge generating material include, but are not particularly limited to, phthalocyanine pigments, perylene pigments, squaric salt pigments, azulenium salt pigments, and quinone condensed polycyclic compounds. Further, the charge transporting layer (protective layer) of the present invention provided on the charge generating layer comprises an organic photoconductive material serving as a charge transporting substance using the above-mentioned abrasion-resistant styrenic resin composition as a binder and other additives ( Weathering aid, antioxidant, plasticizer, etc.).

The organic photoconductive material serving as a charge transporting substance dispersed and contained in the abrasion-resistant styrenic resin composition may be a known poly-n-vinylcarbazole compound,
Pyrazoline compounds, α-phenylstilbene compounds, hydrazone compounds, diarylmethane compounds,
Examples include, but are not particularly limited to, triphenylamine-based compounds, diaminocarbazole-based compounds, fluorein-based compounds, anthracene-based compounds, oxadiazole-based compounds, and divinylbenzene-based compounds. Also,
The charge transporting material may contain a weathering aid, an antioxidant, a plasticizer, and the like, if necessary.

In the present invention, the binder of the coating composition used for the charge transport layer and the protective layer has a content of a polymer block mainly composed of a vinyl aromatic hydrocarbon of 60 to 90 wt% and a conjugated diolefin as described above. Styrene-butadiene block copolymers having a content of polymer blocks mainly composed of 40 to 10 wt% 99 to 30
A styrene resin comprising a blend resin composition of 1 wt% and 1 to 70 wt% of a styrene-methacrylic ester copolymer, wherein the styrene-methacrylic ester copolymer (II) has a reduced viscosity ( dl / g) as X and methacrylic acid ester content (wt%) as Y 1.3 <0.0515Y + X <1.5
(However, 5 <Y <18 and 0.5 <X <1.1)
And a wear-resistant styrenic resin composition having a Taber abrasion of less than 20 mg as measured by JIS K-7204. When a charge transport layer (protective layer) is formed using this, the organic photoconductive material is generally dispersed.

In order to form a charge transport layer or a protective layer on a conductive substrate in the present invention, the above-mentioned abrasion-resistant styrenic resin composition and organic photoconductive material have a ratio of about 1: 1. After uniformly dissolving in a suitable solvent to form a coating composition, apply and dry on the charge generation layer by a coating method such as a dip coating method, a spray coating method, a coating method using a roll coater, or a coating method using an applicator. To remove the solvent. The solvent may be any organic solvent capable of dissolving the abrasion-resistant styrene resin composition and the organic photoconductive material, such as aromatics such as toluene, cyclohexane, benzene, and dichlorobenzene, acetone, and methyl ethyl ketone. And the like with ketones.

In the present invention, the thickness of the charge transport layer is 0.0
It is between 1 and 20 microns, preferably between 0.1 and 10 microns. If the thickness is less than 0.01 micron, it is difficult to make the thickness of the layer uniform. On the other hand, if it exceeds 20 microns, the electrophotographic characteristics are undesirably deteriorated. Further, the thickness of the protective layer is 0.5 to 10 μm, and more preferably 1 to 5 μm.
Preferably it is in the micron range.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below together with examples. First, a method for producing a resin used in Examples of the present invention, a method for evaluating characteristics, and the like will be described. (1) Styrene-methacrylate copolymer (M
Production method of S) As a raw material monomer, various ones in which the mixing ratio of methyl methacrylate (MMA) and styrene (St) is changed are used.
Further, EB was used as a solvent, and t-butyl peroxyisopropyl monocarbonate was used as an initiator in an amount of 200 ppm based on the raw material.
The added mixed raw material is continuously supplied to a complete mixing type full-bed reactor, and polymerization is continued by a bulk polymerization method while maintaining the inside of the reactor at a predetermined temperature and a constant pressure to stabilize the conversion to about 80%. The styrene-methacrylic acid ester having different MMA contents as shown in Table 1 was obtained by a radical polymerization process in which the remaining polymer and the solvent were removed by a twin-screw extruder having a reduced-pressure vent port. Polymer (MS-
1 to MS-13).

[0029]

[Table 1]

(2) Styrene butadiene block copolymer The following two types of commercial products were used. (A) A radially branched block copolymer having a styrene content of about 75 wt% (trade name: K-Resin KR03, manufactured by Philips). (B) Linear block copolymer having a styrene content of about 75 wt% (trade name: TR200, manufactured by Nippon Synthetic Rubber Industry Co., Ltd.)
4).

(3) Blend production method of blended resin composition Each blend ratio of each MS resin and styrene-butadiene block copolymer shown in Table 1 was varied and mixed.
The mixture was kneaded with a biaxial extruder having a diameter of 0 mm to obtain pellets of various compounded resin compositions.

(4) Test Method for Characteristic Evaluation of Compounded Resins, etc. (a) MMA Content of MS Resin The MMA content of the obtained MS resin was determined by pyrolysis gas chromatography analysis (peak area ratio method). Pyrolyzer is Curie Point Pyrolyzer JHP2
The mold (manufactured by Nippon Kayaku Kogyo) and a gas chromatograph analyzer used were GC6AM (manufactured by Shimadzu Corporation) equipped with an FID detector. (B) Melt flow rate of MS resin (MFR: g / 1
0 min) The MFR of the obtained MS resin was determined under the conditions of 200 ° C. and 5 kg according to JIS K-7207.

(C) Measurement of reduced viscosity of MS resin MS resin pellets are dissolved in toluene, reprecipitated with methanol, dried under reduced pressure in a vacuum dryer at 80 ° C. for 24 hours, and pretreated. After dissolving 0.2 g of the pretreated product in 50 ml of toluene, the relative viscosity at 30 ° C. was measured using an Ubbelohde viscometer and converted into a specific viscosity, and then the sample concentration was corrected. The reduced viscosity was calculated from the following formula. Relative viscosity (ηrel) = ts / to Specific viscosity (ηsp) = ηrel-1 Reduced viscosity (ηsp / c) = ηsp ÷ c ts: Flowing time of blank solvent (second) to: Flowing time of sample solution (second) c ; Adjusted concentration of sample solution (g / dl)

(D) Tensile strength and elongation at break of the blended resin composition The tensile strength and elongation at break were measured according to JIS K6301.
A No. 3 dumbbell specimen was prepared and subjected to a tensile test at a test speed of 500 mm / min. (E) Haze calculation of blend resin composition Haze (%) is 0.6 m in thickness according to JIS K6714.
m was measured. (F) Drop Weight Impact Test of Blend Resin Composition Drop weight impact strength (kg · cm) was tested according to JIS K7124.

(G) Taber abrasion test of the blended resin composition 5 g of the obtained blended resin composition and 5 g of the pigment were mixed.
A coating solution dissolved in 60 ml of dichlorobenzene solvent,
This was applied to a glass substrate using a coater. After removing the solvent with a vacuum dryer, a cast plate of about 30 μm was obtained. A Taber abrasion test was performed using a worn wheel CS-10 according to JIS K-7204 (a method of testing abrasion of a plastic with a worn wheel). The turntable rotation speed is 60
The rpm and the load were 1000 gf. The test was performed three times, and the average of the test values was calculated and shown as the amount of wear (mg).

Examples 1 to 5 and Comparative Examples 1 to 8 Various MS resins shown in Table 1 (MS1-MS13 and K-resin KR03 were blended at a blend ratio of 40:60 each (total
100), after kneading with a 40 mm diameter extruder to obtain a blended resin composition, the results of the various physical property evaluation tests described above are summarized in Tables 2 and 3. From Table 2 and Table 3,
The physical properties and the like of the blended resin compositions (Examples 1 to 5) satisfying the requirements stipulated in the present invention are the same as the blended resin compositions (Comparative Examples 1 to 8) that do not satisfy the requirements stipulated in the present invention. It turns out that it is excellent compared with ()).

Examples 6 and 7 The blend ratio of MS resin to K-resin KR03 and TR2004 was 34: 60: 6, respectively (total 100).
After kneading into a blended resin composition with an extruder having a diameter of 0 mm, the results of the various physical property evaluation tests described above are summarized in Tables 2 and 3. It can be seen that all of them show excellent physical properties.

Examples 8 to 13 MS-2 was used as the MS resin, and the blending ratio with K-Resin KR03 was changed (total 100).
After kneading with a m-diameter extruder to obtain a blended resin composition, Table 2 shows the test results of the falling weight impact strength and the haze among the physical properties described above. It can be seen that all of them show excellent physical properties.

Comparative Example 9 The MS resin was changed to a general-purpose polystyrene (GP-1) and K-
The blend ratio with resin KR03 is 40/60 (t
otal 100), kneaded with a 40 mm diameter extruder to form a blended resin composition, and the results of the various physical property evaluation tests described above are summarized in Tables 2 and 3. It can be seen that the falling weight impact strength, tensile strength, Taber abrasion characteristics and the like are inferior.

[0040]

[Table 2]

[0041]

[Table 3]

Example 14 3.5 g of a polyamide resin CM8000 (manufactured by Toray Industries, Ltd.) and 3.5 g of melamine ML2000 (manufactured by Hitachi Chemical Co., Ltd.) were mixed in a methanol / methylene chloride 50/50 mixed solvent 93 g.
And applied to a conductive substrate made of an aluminum plate having a thickness of 1 mm with an applicator, and dried at 120 ° C. for 20 minutes to form an undercoat layer having a thickness of 0.4 μm. Next, a bisazo pigment (the following chemical formula 1) as a charge generating substance was added to 1
0 g and 10 g of polyvinyl formal resin are kneaded using a ball mill for 30 hours, and then tetrahydrofuran (T
HF) was added, and the dispersion was applied from above the undercoat layer with an applicator and dried at 120 ° C. for 30 minutes to form a charge generation layer having a thickness of 0.4 μm.

Next, 10 g of a hydrazone-based pigment (the following chemical formula 2), which is an organic photoconductive material, was added to MS obtained in Example 6.
Dissolve 10 g of the resin composition of -1 / KR03 / TR2004 in 34/60/6 in 80 g of dichlorobenzene solvent, apply the solution on the charge generation layer with an applicator, and dry at 100 ° C. for 1 hour to obtain a film thickness of 1
An electrophotographic photoreceptor having a 0 μm charge generation layer and a charge transport layer (protective layer) was formed. A cross-cut tape method (JIS K-) was applied on the charge transport layer (protective layer) of the electrophotographic photoreceptor.
5400), the adhesion of the electrophotographic photosensitive member was evaluated. The interval between the cuts was 2 mm, and the number of cuts was 25. As a result of the test five times, the evaluation score was 8 to 10 points, and although a slight peeling was confirmed at the intersection of the cuts, there was no peeling at a glance of the square, and the area of the defective part was within 5% of the total square area. Alternatively, each cut was fine and smooth, and there was no separation between the intersection of the cut and each square.

[0044]

Embedded image

[0045]

Embedded image

Comparative Example 10 The same procedure as in Example 14 was carried out except that the GP-1 / KR03 obtained in Comparative Example 9 was used as the resin for the charge transport layer (protective layer). The evaluation score of the adhesion by the crosscut tape method was 4 points as a result of the test five times, and the width of the peeling due to the cut was wide, and the area of the defective portion was about 15 to 35% of the entire square area.

[0047]

The styrenic resin composition according to the present invention comprises:
Excellent in wear resistance when evaluated by the Taber abrasion amount and excellent adhesion to the substrate of the electrophotographic photoreceptor formed, so it is widely used for sliding parts with wear in the electrical and mechanical fields. can do. In particular, when it is used in a charge transport layer (protective layer) of an electrophotographic photoreceptor by being dissolved in a general aromatic solvent such as toluene and making use of its abrasion resistance, it is economically excellent because it is inexpensive.

Claims (5)

[Claims] 1. A 60～90Wt% content of the polymer block mainly composed of vinyl aromatic hydrocarbon content of the polymer block composed mainly of a conjugated diolefin is 40 to 10
A blend resin composition comprising 99 to 30 wt% of a styrene-butadiene block copolymer (I) of 1 to 70 wt% and 1 to 70 wt% of a styrene-methacrylic acid ester-based copolymer (II). When the acid ester-based copolymer (II) has a reduced viscosity (dl / g) of X and a methacrylate content (wt%) of Y, 1.3 <0.0515Y + X <1.5
(However, 5 <Y <18 and 0.5 <X <1.1)
And a Taber abrasion amount of less than 20 mg measured according to JIS K-7204. 2. The styrene-butadiene block copolymer (I) has a general formula (AB) _n Z (where A is a vinyl aromatic hydrocarbon polymer block and has a content of 60 to 9).
0 wt%, B is a conjugated diene polymer block having a content of 40 to 10 wt%, Z represents a residue of a polyfunctional coupling agent used for forming a radially branched block copolymer, and n represents a residue. The styrenic resin composition according to claim 1, which is a radially branched block copolymer represented by the following formula (indicating the number of functional groups of the polyfunctional coupling agent and being an integer of at least 3). 3. Tensile strength (σ: kgf / mm ² )
The styrenic resin composition according to claim 1 or 2, wherein the product (σ · ε) of the elongation and the elongation (ε: unit%) is 600 or more. 4. A coating composition for an electrophotographic photosensitive member, comprising the abrasion-resistant styrenic resin composition according to claim 1, a solvent, and an organic photoconductive material. 5. An electric charge for an electrophotographic photosensitive member, wherein an organic photoconductive material is dispersed and contained using the abrasion-resistant styrenic resin composition according to claim 1 as a binder. Transport layer and / or protective layer.