JPH11133786A - Separation pawl for copying machine composed of polyimide resin crystallizing in metallic mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve surface smoothness and sliding property, to eliminate the need of after-anneal and to reduce production cost by using a resin composition containing a specific thermoplastic crystalline polyimide resin crystallizing in a metallic mold. SOLUTION: A separation pawl for copying machine is composed of the crystalline polyimide resin having a repeating unit expressed by the formula and 0.1-3.0 dl/g logarithmic viscosity (ηinh). And the separation pawl is composed of a fiber reinforced resin composition containing 5-100 pts.wt. fibrous reinforcing material per 100 pts.wt. crystalline polyimide resin. And at the time of injection molding, the composition is crystallized in the metallic mold. By attaining the crystallization in the metallic mold, the heat resistance of the crystalline polyimide resin of its own is exhibited and a molding small in the dimensional change caused by a technique such as after-crystallization is obtained. That is, the tip shape, which is a key point of the separation pawl, is accurately molded and the separation actin for copying machine is surely improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention has excellent surface smoothness,
The present invention relates to a separating claw for a copying machine, which has good sliding characteristics, does not require post-annealing, and significantly reduces manufacturing costs.

[0002]

2. Description of the Related Art A separating claw for a copying machine is used to remove the paper onto which a toner image has been transferred from a fixing roller in a copying machine without causing the paper to be wrapped around the roller. Used to scoop the edge of Therefore, the separating claw for a copying machine is required to be excellent in friction and wear characteristics, not to damage the outer peripheral surface of the roller, and to be excellent in so-called sliding characteristics so as not to damage itself. In addition, characteristics such as excellent mechanical strength at high temperatures, and particularly excellent dimensional accuracy of the shape of the tip portion are required.

[0003] In particular, in recent years, the copying speed has been increased, and accordingly, the heating temperature of the fixing roller is often higher than before. Separating claw in contact with roller is also 2
Heat resistance of 50 ° C. or more, sometimes 300 ° C. or more, is required. As a polymer material that can be used at such a high temperature, a polyimide resin can be given. A conventionally developed separating claw for a copying machine is disclosed in JP-A-62-236858,
Although a thermoplastic polyimide resin is used as disclosed in JP-A-62-253655, it is difficult to take out a crystallized state in a mold during injection molding due to a low crystallization rate. It had to be used in a crystalline state, and thus it could not be said that the heat resistance characteristic of the polyimide resin was sufficiently exhibited. In order to sufficiently exhibit heat resistance, there is a means called crystallization. The polyimide resin can be post-crystallized using an oven or the like, but it takes time, or a dimensional change occurs due to crystallization when post-crystallizing, and the dimensional accuracy required for the separation claw is not sufficient. However, it cannot be said that this is a sufficient method, and it has been required that crystallization be achieved in a mold for injection molding. Then, the present inventors further disclosed in JP-A-07-19036.
As disclosed in No. 9, it has been found that the crystallization rate can be remarkably improved by adding a specific graphite to a thermoplastic polyimide. As a result, a polyimide resin crystallized in the mold could be obtained.However, the mold temperature was extremely high, and there were various problems such as galling of the mold and deformation of the product at the time of protrusion. It was inadequate and was not satisfactory as a material for separation nails for copying machines.

[0004]

The problem to be solved by the present invention is to overcome the above-mentioned problems, to provide excellent surface smoothness, good sliding properties, no need for post-annealing, and significant production costs. It is an object of the present invention to provide a separating claw for a copying machine which is reduced.

[0005]

In order to solve these problems, the present inventors have studied various types of separation claws for general-purpose plastics and engineering plastics for copying machines, and have found that thermoplastic crystallization occurs in a mold. Using a resin composition containing a crystalline polyimide resin, the separation claw for a copying machine crystallized in a mold by injection molding was found to be optimal,
The present invention has been completed. That is, the present invention is specified by the following items [1] to [5]. [1] General formula (1)

[0006]

Embedded image And a logarithmic viscosity (ηinh) is
Separation claws for a copying machine made of a crystalline polyimide resin having a weight ratio of 0.1 to 3.0 dl / g.

[2] It has a repeating structural unit of the general formula (1) (Formula 2), and has a logarithmic viscosity (ηinh) of 0.1 to
A separation nail for a copying machine, comprising a fiber reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin having a weight of 3.0 dl / g. [3] It has a repeating structural unit of the general formula (1) (Formula 2), and has a logarithmic viscosity (ηinh) of 0.1 to 3.0 dl / g.
When injection molding a crystalline polyimide resin that is
A method for producing a separation claw for a copying machine, wherein the separation claw is crystallized in a mold.

[4] It has a repeating structural unit of the general formula (1) (formula 2) and has a logarithmic viscosity (ηinh) of 0.1 to
When performing injection molding of a fiber reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin of 3.0 dl / g, crystallization is performed in a mold. A method for manufacturing a separating claw for a copying machine, which is characterized by the following. [5] A separating claw for a copying machine obtained by the manufacturing method according to [3] or [4].

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Crystallization of a resin composition for use in a separation nail for a copying machine of the present invention is achieved in a mold. By achieving crystallization in the mold, the heat resistance inherent to the polyimide resin is exhibited, and a molded product with less dimensional change due to a method such as post-crystallization can be obtained. The polyimide resin used in the present invention is a diamine represented by the general formula (2)

[0010]

Embedded image And a tetracarboxylic dianhydride represented by the general formula (3):

[0011]

Embedded image And dehydration co-condensation of

The molecular weight of the polyimide is a logarithmic viscosity (ηin
h) is in the range of 0.1 to 3.0 dl / g. Preferably it is in the range of 0.2 to 2.0 dl / g, more preferably 0.1 to 2.0 dl / g.
Range from 3 to 1.5 dl / g, most preferably from 0.4 to
It is in the range of 1.0 dl / g. If it is less than 0.1 dl / g, the molecular weight is low and the strength as a molded product cannot be sufficiently exhibited. If it exceeds 3.0 dl / g, the molecular weight is too high, and melt molding such as injection molding becomes difficult.

In the present invention, the logarithmic viscosity (ηin)
h) is p-chlorophenol / phenol (weight ratio 9)
/ 1) A value measured at 35 ° C. after heating and dissolving 0.50 g of polyimide powder in 100 ml of a mixed solvent. A known imidization reaction can be applied to the method for producing the polyimide resin. The amount of the starting compound used is usually 0.90 equivalent of tetracarboxylic dianhydride to 1 equivalent of diamine.
It is in the range of 0.99 equivalents. Preferably 0.93-0.
985, more preferably 0.95 to 0.98. If the molecular weight is less than 0.90 equivalent, the molecular weight is not sufficiently high, so that the mechanical properties of the obtained polymer may not be sufficient. If it exceeds 0.99, there is a problem that the molecular weight becomes too high and the fluidity is impaired.

In the synthesis of the polyimide, it is desirable to seal the reactive end of the molecule with phthalic anhydride or the like. By sealing the reaction end, the thermal stability is significantly improved. The reaction is particularly preferably performed in an organic solvent. Examples of the solvent usable here include N, N-dimethylformamide, N, N-diethylacetamide, N, N-dimethoxyacetamide, N-methyl-2-pyrrolidone,
3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2 -Methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,3-
Dioxane, 1,4-dioxane, pyrroline, picoline, dimethylsulfoxide, dimethylsulfone, tetramethylurea hexamethylphosphoramide, phenol,
o-cresol, m-cresol, p-cresol, p
-Chlorophenol, anisole, benzene, toluene, xylene and the like. These may be used alone or in combination of two or more.

[0015] The reaction temperature is usually in the range of room temperature to 250 ° C, preferably in the range of 140 ° C to 200 ° C. The reaction pressure is not particularly limited, and the reaction can be sufficiently performed at normal pressure. The reaction time varies depending on the type of the solvent and the reaction temperature, but is usually 4 to 24.
Time. Further, as a method of imidation, a polyamide acid as a precursor is heated to 100 to 300 ° C. to imidize or chemically imidized using an imidizing agent such as acetic anhydride to obtain a desired polyimide resin. Is obtained. When using the resin composition, the mold temperature is from 180 to
280 ° C. range. It is preferably in the range of 190 to 270 ° C, more preferably in the range of 200 to 265 ° C, and most preferably in the range of 210 to 260 ° C. If the mold temperature exceeds 280 ° C., the molded product may not be released.
At a mold temperature of less than 180 ° C., the crystallization of the crystalline polyimide resin does not sufficiently proceed, and the heat resistance at a high temperature peculiar to the polyimide resin cannot be exhibited as it is. When a molded article is taken out in an amorphous state and then crystallized, deformation may increase with the post-crystallization, and a shape that can withstand use may not be maintained.

Other thermoplastic resins can be added in an appropriate amount according to the purpose within a range not to impair the object of the present invention. Thermoplastic resins that can be blended include polyether ketone, polyether ether ketone, polyether ketone ketone, polyether ketone ether ketone ketone, polyethylene, polypropylene, polystyrene, polycarbonate, polyester, polyamide,
Polyamide imide, polyphenylene ether, polyacetal, polyether imide, polyether sulfone,
Polysulfone and other thermoplastic polyimides.

It is also possible to mix a thermosetting resin and a filler to such an extent that the object of the invention is not impaired. Examples of the thermosetting resin include a phenol resin and an epoxy resin. Examples of the filler include a silica powder, molybdenum disulfide, an abrasion resistance improving material such as a fluororesin, carbon fiber, glass fiber, aromatic polyamide fiber, alumina fiber, boron fiber, silicon carbide fiber, potassium titanate whisker, and aluminum borate. Reinforcing materials such as whiskers, carbon whiskers, asbestos, metal fibers, and ceramic fibers; flame retardant materials such as antimony trioxide, magnesium carbonate, and calcium carbonate; electric property improving materials such as clay and mica; asbestos and silica; Tracking resistant material,
Acid-resistance improving materials such as barium sulfate, silica, calcium metasilicate, etc .; thermal conductivity improving materials such as iron powder, zinc powder, aluminum powder, and copper powder; and other polybenzimidazole resins, silicon resins, glass beads, talc, and diatoms Soil, alumina, silas balun, hydrated alumina, metal oxides, coloring agents, release agents, various stabilizers, plasticizers and the like.

The resin composition of the present invention can be produced by a generally known method, but the following method is particularly preferable. (1) Crystalline polyimide resin powder, fibrous reinforcing material such as carbon fiber, and other additives are mixed with a mortar, a Henshal mixer,
Premixing is performed using a drum blender, a tumbler blender, a ball mill, a ribbon blender, and the like, and the mixture is kneaded with a generally known melt extruder, melt mixer, hot roll, or the like, and then pelletized or powdered.

(2) A crystalline polyimide resin powder and other additives are dissolved or suspended in an organic solvent in advance, and a fibrous reinforcing material such as carbon fiber is immersed in the solution or suspension. Is removed in a hot air oven and then pelletized or powdered. In this case, examples of the solvent used include N, N-dimethylformamide, N, N
-Dimethylacetamide, N, N-diethylacetamide, N, N-dimethylmethoxyacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, 1,2-dimethoxyethane , Bis (2-methoxyethyl) ether,
1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, pyridine, picoline, dimethylsulfoxide,
Examples include dimethyl sulfone, tetramethyl urea, and hexamethyl phosphoramide. These organic solvents may be used alone or in combination of two or more.

The resin composition of the present invention is molded by a known molding method such as an injection molding method, an extrusion molding method, a compression molding method, or a transfer molding method, and put into practical use. The separation claw according to the present invention is significantly improved in surface properties as compared with a post-annealed one by crystallization in a mold during injection molding. This improvement in the surface properties leads to a marked improvement in the properties of the separating claw, namely the friction and wear properties. The surface properties are clearly superior to those crystallized in the mold as compared with the amorphous separation claws of the prior art.

Also, by crystallization in the mold during injection molding, the dimensional accuracy can be more easily predicted than in the case of post-annealing, and the dimensional accuracy can be accurately controlled in practice. That is, the tip shape serving as the key point of the separation claw can be molded with high precision, and the separating action for the copying machine is surely improved. The appearance of the molded article is extremely good. It is clear that the crystallization in the mold does not require post-annealing to complete the crystallization, greatly reducing the processing cost.

[0022]

The present invention will be described in more detail with reference to the following examples. Synthesis Example of Polyimide Resin 140 g of 3,4′-diaminodiphenyl ether (0.1 g) was placed in a container equipped with a stirrer, a reflux condenser, and a nitrogen inlet tube.
7 mol), 195.5 g (0.665 mol) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 10.4 g (0.1 mol) of phthalic anhydride, m-cresol 1
480 g were charged, and the mixture was stirred for 200 hours under a nitrogen atmosphere.
The temperature was raised to ℃. Thereafter, the reaction was carried out at 200 ° C. for 4 hours, during which time about 9 ml of water was distilled off.
After the completion of the reaction, the mixture was cooled to room temperature, charged with about 2000 ml of toluene, and then the polyimide powder was separated by filtration. After washing this polyimide powder with toluene, it was dried at 250 ° C./5 hours in nitrogen to obtain a polyimide powder. Η of the obtained polyimide powder
inh was 0.55 dl / g.

Example 1 The polyimide resin and carbon fiber (HTA-C6-TX manufactured by Toho Rayon Co., Ltd.) obtained in the synthesis example were blended in the proportions shown in Table 1 and mixed, and then heated at 410 ° C. with a 40 mm diameter extruder. The pellets were melt-kneaded to obtain pellets. The obtained pellets were subjected to a cylinder temperature of 410 using an injection molding machine having a mold clamping force of 100 tons.
C. and a mold temperature of 230.degree. C. to obtain an ASTM bending test piece, a Suzuki-type friction and wear test piece, and a molded product in the shape of a separation claw. The appearance was good and a glossy separation nail was obtained. The molding conditions and the like are summarized in Table 1 [Table 1].

(1) Deflection temperature under load Measured according to ASTM-D-648 using a bending test piece. (2) Dimensional change before and after crystallization The shrinkage in the MD direction before and after crystallization was measured using a bending test piece. (3) Friction coefficient and specific wear amount A Suzuki-type friction wear test was performed at a surface pressure of 5 kg / cm2 and a speed of 50 m / min under conditions of SUS304 as a mating material and 7 hours of non-lubrication. After 7 hours, the friction coefficient and the specific wear amount were measured. Further, the separation claw was attached to a predetermined position in contact with a heating roller (PFA coating) of the copying machine. The separation claw of the present invention has good properties without damaging the roller, has no toner adhesion, and does not show any wear of the claw itself. I was satisfied with. The experimental results are summarized in Table 2 [Table 2].

Comparative Example 1 The resin used was a thermoplastic polyimide "AURUM PL"
An experiment was performed in the same manner as in Example 1 except that the test piece was changed to 450 "(registered trademark: manufactured by Mitsui Chemicals, Inc.). The test results and the like are summarized in Tables 1 and 2. The test pieces obtained in this comparative example are: Since it was obtained in an all-amorphous state, it was crystallized by post-annealing at 260 ° C./10 h and then 300 ° C./2 h. Furthermore, the tip of the separation claw was significantly worn as compared with Example 1, and the service life was about 比 べ of that obtained in Example 1.

[0026]

[Table 1] Table 1 Example Composition Comparative example AURUM CF cylinder temperature obtained by synthesis example Mold temperature Remarked polyimid (° C) (° C) ───────────────── ─────────────────── Example 1 70 30 410 230 Comparative Example 1 70 30 400 200 No crystallization in mold ───────────────────────────

[0027]

[Table 2] Table 2 Example 1 Comparative Example 1 ──────────────────────────────────── Load deflection Temperature (° C) (1) 260 or more 248 収縮 Shrinkage (% 1.1) ──────────────────────────────────── Friction coefficient 10 0.20 Specific wear (3) 52 140 ──────────────────────────────────── (1 All figures are for mold removal products. (2) Since Example 1 is crystallized in the mold, post-crystallization is unnecessary. Comparative Example 1 does not crystallize in the mold, and thus shows the shrinkage ratio before and after post-crystallization. (3) Unit: 10 ^-10 cm ³ / kgfm

[0028]

As described above, the separating claw for a copying machine using the crystalline polyimide resin composition which crystallizes in the mold according to the present invention is crystallized in the mold. Compared with the dimensional accuracy, heat resistance is improved, and friction and wear characteristics are improved.

Claims (5)

[Claims] 1. A compound represented by the general formula (1): And a logarithmic viscosity (ηinh) is
Separation claws for a copying machine made of a crystalline polyimide resin having a weight ratio of 0.1 to 3.0 dl / g. 2. It has a repeating structural unit of the general formula (1) (formula 1), and has a logarithmic viscosity (ηinh) of 0.1 to 3.0 d.
A separating claw for a copying machine, comprising a fiber reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin of 1 / g. 3. It has a repeating structural unit of the general formula (1) (formula 1), and has a logarithmic viscosity (ηinh) of 0.1 to 3.0 d.
A method for producing a separating claw for a copying machine, wherein a l / g crystalline polyimide resin is crystallized in a mold at the time of injection molding. 4. It has a repeating structural unit of the general formula (1) (formula 1), and has a logarithmic viscosity (ηinh) of 0.1 to 3.0 d.
When injection molding of a fiber reinforced resin composition containing 5 to 100 parts by weight of a fibrous reinforcing material with respect to 100 parts by weight of a crystalline polyimide resin of 1 / g, crystallization is performed in a mold. Manufacturing method of a separation claw for a copying machine. 5. A separating claw for a copying machine obtained by the method according to claim 3.