JP2002363237A - Electroconductive polyurethane foam member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroconductive polyurethane foam member having stable microcells and good appearance. SOLUTION: This electroconductive polyurethane foam member is obtained by mixing together under agitation of a polyol, a polyisocyanate, an electrolyte, a foam stabilizer, a catalyst and water, wherein the foam stabilizer consists of a polyether-modified silicone represented by formula (1) (where, R<1> is a 1-8C alkylene group; R<2> is a 1-20C hydrocarbon group; EO is ethylene oxide; PO is propylene oxide; (n) is an integer of 1-5; (a) is an integer of 10-30; and (b) is an integer of 5-20).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polyurethane foam member comprising a polyurethane foam having fine cells, which is used in an image forming apparatus such as an electrophotographic apparatus, an electrostatic recording apparatus and a toner flying recording apparatus. And an image forming apparatus equipped with the conductive polyurethane foam member.

[0002]

2. Description of the Related Art In recent years, with the progress of electrophotographic technology, image forming apparatuses such as dry electrophotographic apparatuses have been used as members for charging, developing, transferring, and supplying toner.
Attention has been paid to members made of polymer materials, and they are used in the form of elastic rollers such as a charging roller, a developing roller, a transfer roller, and a toner supply roller. Conventionally, members used for such purposes include NBR, EP
There are elastomers and foams such as DM, silicone rubber, and polyurethane, and among them, polyurethane foam is preferably used because a low-hardness member suitable for the above-mentioned members can be obtained. As a method for obtaining a conductive polyurethane foam, a water foaming method in which a conductive carbon such as carbon black, a foam stabilizer, and a catalyst are blended with a polyol and a polyisocyanate, and foaming is performed using water as a foaming agent, a polyol and a polyisocyanate To
A method in which an electrolyte, a foam stabilizer, and a catalyst are blended and foamed by mechanical stirring has been used. However, in the above method, there is a problem that the conductive position variation in the polyurethane foam is large, and in the above method, there is a problem that a polyurethane foam having a low Asker C hardness of 30 ° or less cannot be obtained. . Therefore, in the water foaming method, a method of producing a polyurethane foam using an electrolyte instead of conductive carbon was attempted, but in this method, due to salting out, the effectiveness of a foam stabilizer as a surfactant is reduced. Therefore, there is a problem that the cell state of the polyurethane foam deteriorates, that is, the foam shrinks. As a catalyst, dibutyltin diacetate,
Tin compounds such as dibutyltin dilaurate, dibutyltin marker peptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker peptide, and dioctyltin thiocarboxylate are frequently used. When water is contained in the polyurethane, it is hydrolyzed and the catalytic activity is deteriorated, so that it is not possible to obtain a good foam continuously. It was desired to get the form.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a conductive polyurethane foam member having fine cells and good appearance, and an image forming apparatus equipped with the member. It is intended to provide.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, when producing a conductive polyurethane foam member by a water foaming method, a polyol and a polyisocyanate are specified. It has been found that, by blending the foam stabilizer, a ionic conductive polyurethane foam member having stable fine cells and good appearance can be obtained without using a tin compound as a catalyst. The present invention has been completed based on such findings. That is, the present invention provides a member comprising a conductive polyurethane foam obtained by stirring and mixing a polyol, a polyisocyanate, an electrolyte, a foam stabilizer, a catalyst and water, wherein the foam stabilizer is represented by the following general formula (1):

[0005]

Embedded image

Wherein R ¹ is an alkylene group having 1 to 8 carbon atoms, R ² is a hydrocarbon group having 1 to 20 carbon atoms, EO is ethylene oxide, and PO is propylene oxide.
Is an integer of 1 to 5, a is an integer of 10 to 30, b is 5 to 20
Is an integer. The present invention provides a conductive polyurethane foam member which is a polyether-modified silicone represented by the formula (1) and an image forming apparatus equipped with the polyurethane foam member.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyurethane foam member of the present invention is composed of a polyurethane foam produced using polyol and polyisocyanate as main raw materials. As the polyol, a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide, polytetramethylene ether glycol, a polyester polyol obtained by condensing an acid component and a glycol component, a polyester polyol obtained by ring-opening polymerization of caprolactone, and a polycarbonate diol are used. Can be. Polyether polyols obtained by addition polymerization of ethylene oxide and propylene oxide include, for example, water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, methylglucode, Starting materials are aromatic diamines, sorbitol, sucrose, phosphoric acid, and the like, and examples of addition polymerization of ethylene oxide and propylene oxide include water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, and the like. Those using hexanetriol as a starting material are preferred. As for the ratio of ethylene oxide and propylene oxide to be added and the microstructure, the ratio of ethylene oxide is preferably from 2 to 95% by mass, more preferably from 5 to 90% by mass, and particularly preferably from 5 to 30% by mass.
It is. Those having ethylene oxide added to the terminal are preferably used. Also, the arrangement of ethylene oxide and propylene oxide in the molecular chain is preferably random. Although the molecular weight of this polyether polyol is not particularly limited, the number of functional groups is 1.5 to 4
And a weight average molecular weight of 2000 to 6000 is preferable, and 4000 to 5500 is more preferable.

The polyol may be pre-polymerized with a polyisocyanate in advance. The method is as follows. The polyol and the polyisocyanate are put in an appropriate container, sufficiently stirred, and kept at 30 to 90 ° C., more preferably 40 to 90 ° C.
~ 70 ° C for 6-240 hours, more preferably 24-7
There is a method of keeping the temperature for 2 hours. In this case, the ratio of the amounts of polyol and polyisocyanate is preferably adjusted so that the isocyanate content of the obtained prepolymer is 4 to 30% by mass, more preferably 6%.
１５15% by mass. If the content of the isocyanate is less than 4% by mass, the stability of the prepolymer may be impaired, and the prepolymer may be hardened during storage and may not be usable. On the other hand, when the isocyanate content exceeds 30% by mass, the content of the non-prepolymerized polyisocyanate increases, and the polyisocyanate reacts with the polyol component used in the subsequent polyurethane curing reaction with the prepolymerization reaction. Since the curing is carried out by a reaction mechanism similar to the one-shot production method without passing through, the effect of using the prepolymer method is weakened.

Examples of the polyisocyanate constituting the polyurethane foam include toluene diisocyanate, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), isophorone diisocyanate and derivatives thereof. The diphenylmethane diisocyanate or a derivative thereof is not particularly limited. For example, diphenylmethane diisocyanate or a derivative thereof obtained by phosgenating diaminodiphenylmethane or a derivative thereof is used. Examples of the derivative of diaminodiphenylmethane include polynuclear substances, such as pure diphenylmethane diisocyanate obtained from diaminodiphenylmethane, and polymeric diphenylmethane diisocyanate obtained from a polynuclear substance of diaminodiphenylmethane. Polymeric
The number of functional groups of diphenylmethane diisocyanate is not particularly limited, but usually a mixture of pure diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate having various functional groups is used, and the average number of functional groups is preferably from 2.05 to 4.00, Preferably
2.50 to 3.50 are used. Derivatives obtained by modifying these diphenylmethane diisocyanates or derivatives thereof, for example, urethane-modified products modified with polyols, dimers formed by forming uretdione, isocyanurate-modified products, carbodiimide / uretonimine-modified products, allohanate-modified products, urea Modified products, buret modified products and the like can also be used.

In the present invention, diphenylmethane diisocyanate or a derivative thereof may be used alone or in a combination of two or more. Further, if desired, various aromatic isocyanates such as tolylene diisocyanate, various aliphatic isocyanates such as hexamethylene diisocyanate, and alicyclic rings such as isophorone diisocyanate together with the above diphenylmethane diisocyanate and derivatives thereof within a range that does not impair the object of the present invention. Aromatic isocyanates or derivatives thereof can be used in combination. Among these isocyanates, in the present invention, toluene diisocyanate, tolylene diisocyanate (T
DI), a mixture of TDI and polymeric diphenylmethane diisocyanate, a modified polyol of TDI,
And a polyol-modified product of polymeric diphenylmethane diisocyanate. In the present invention, the compounding amount of the isocyanate is not particularly limited, but the compounding amount is preferably such that the NCO group (isocyanate group) content is 2 to 48.2% by mass, more preferably 20 to 4%.
8.2% by weight.

[0011] The conductive polyurethane foam member of the present invention is provided with conductivity by an electrolyte. Examples of the electrolyte include tetraethylammonium, tetrabutylammonium, dodecyltrimethylammonium (eg, lauryltrimethylammonium), hexadecyltrimethylammonium, octadecyltrimethylammonium (eg, stearyltrimethylammonium),
Perchlorates and chlorates of quaternary ammoniums such as benzyltrimethylammonium, modified fatty acid dimethylethylammonium, lauroylaminopropyldimethylethylammonium, alkali metals such as lithium and sodium or alkaline earth metals such as calcium and magnesium , Hydrochloride, bromate, iodate, borofluoride, sulfate, alkyl sulfate, carboxylate, sulfonate, trifluoromethyl sulfate and the like. In the present invention, among these, alkali metal perchlorates (such as sodium perchlorate) are preferable. The amount of the electrolyte is preferably from 0.3 to 3.5 parts by mass, more preferably from 2.0 to 3.3 parts by mass, per 100 parts by mass of the polyol. In the present invention, the following general formula (1) is used as a foam stabilizer.

[0012]

Embedded image

Wherein R ¹ is an alkylene group having 1 to 8 carbon atoms, R ² is a hydrocarbon group having 1 to 20 carbon atoms, EO is ethylene oxide, and PO is propylene oxide.
Is an integer of 1 to 5, a is an integer of 10 to 30, b is 5 to 20
Is an integer. ) Is used. The polyether-modified silicone, polyether - is called a _{^{(-R 1 (EO) a /}} (PO) b -R 2) is pendant attached to the intermediate portion (P-type). R ¹ is an alkylene group having 1 to 8 carbon atoms,
Preferably an alkylene group having 2 to 6 carbon atoms, especially trimethylene group _{(-CH 2 CH 2 CH 2 -} ) is preferred. Examples of the hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group,
alkyl groups such as tert-butyl group and n-hexyl group;
Examples thereof include an aryl group such as a phenyl group and an aralkyl group such as a benzyl group. In the present invention, the number of carbon atoms is 1
~ 5 alkyl groups are preferred. n is an integer of 1 to 5; a is an integer of 10 to 30; b is an integer of 5 to 20; n is preferably 2 to 4; a is preferably 15 to 28;
To 15 are preferred. The compounding amount of the foam stabilizer is preferably 0.5 to 2.5 parts by mass, more preferably 0.7 to 1.5 parts by mass, per 100 parts by mass of the polyol.

As a reaction catalyst for curing a composition containing a polyol, an isocyanate, an electrolyte and a foam stabilizer, for example, monoamines such as triethylamine and dimethylcyclohexylamine, tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexane Diamines such as diamines, triamines such as pentamethyldiethylenetriamine, pentamethyldipropylenetriamine and tetramethylguanidine; cyclic amines such as triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine and dimethylimidazole; Dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methylhydroxyethyl Piperazine, alcohol amines such as hydroxyethyl morpholine, bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl) ether amines such as aminopropyl ether. Of these, triamines (tertiary amines) are preferred from the viewpoint of optimizing the reaction rate (curing rate). These catalysts may be used alone or in combination of two or more.

The conductive polyurethane foam member of the present invention is prepared by mixing polyol, isocyanate, electrolyte, foam stabilizer, catalyst and water with stirring and casting the mixture into a predetermined mold or the like, or performing free foaming in a block shape. After that, a method of curing by heating is preferably used. The polyurethane foam member of the present invention can be used for various applications.
It can be particularly preferably used as a transfer roller or a toner supply roller. These rollers have a polyurethane shaft formed around a metal shaft.
As the metal shaft, a steel shaft such as sulfur free-cutting steel plated with zinc or the like, or a shaft made of aluminum, stainless steel, phosphor bronze, or the like can be used.

FIG. 1 is an explanatory view showing an example of an electrophotographic image forming apparatus in which the conductive polyurethane foam member of the present invention is mounted as a transfer roller 5, and illustrates a toner supply roller 3 and a latent electrostatic latent image. The developing roller 2 is disposed between the held image forming body 1 and the outer peripheral surface thereof close to the surface of the image forming body 1, and the developing roller 2 is provided on the image forming body 1 via a recording medium 8 such as paper. The structure in which the transfer roller 5 is brought into contact is shown. The toner is supplied to the surface of the developing roller 2 by the toner supply roller 3 by rotating the toner supply roller 3, the developing roller 2, and the image forming body 1 in the direction of the arrow, and the uniform thin layer is formed by the layer regulating blade 4. Then, the latent image is adhered to the latent image on the image forming body 1 and the latent image is visualized. Then, by generating an electric field between the image forming body 1 and the transfer roller 5, the toner image on the image forming body 1 is transferred to the recording medium 8. A cleaning roller 6 removes toner remaining on the surface of the image forming body 1 after transfer. Reference numeral 7 denotes a charging roller. Specific examples of the image forming apparatus include a plain paper copying machine, a plain paper facsimile machine, a laser beam printer, a color laser beam printer, and a toner jet printer.

[0017]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 and Comparative Examples 1 and 2 The components shown in Table 1 were stirred and mixed, the mixture was cast into a cup, and then heated and cured at 60 ° C. for 1 hour to produce a cylindrical polyurethane foam. Was visually determined. Table 1 shows the results.

[0018]

[Table 1]

(Note) Hiflex 445: Polyether polyol Kaorizer No. manufactured by Daiichi Pharmaceutical Co., Ltd. 31: Kao Corporation, tertiary amine catalyst SF2965: Toray Dow Corning Silicone Co., Ltd.
Silicone foam stabilizer (branched polyether-modified silicone) SRX274C: Silicone foam stabilizer (pendant polyether-modified silicone) manufactured by Dow Corning Toray Silicone Co., Ltd.

[0020]

The conductive polyurethane foam member of the present invention has stable fine cells and good appearance.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of an electrophotographic image forming apparatus in which a conductive polyurethane foam member of the present invention is mounted as a transfer roller.

[Explanation of symbols]

 1: Image forming body 2: Developing roller 3: Toner supply roller 4: Layer regulating blade 5: Transfer roller 6: Cleaning roller 7: Charging roller 8: Recording medium

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/16 103 G03G 15/16 103 // C08J 9/12 C08J 9/12 (C08G 18/00 C08G 101 : 00 101: 00) (72) Inventor Yuichiro Mori 1 Kashio-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in Bridgestone Yokohama Plant (reference) 2H077 AA15 AC04 AD06 FA22 FA27 2H200 FA02 HA02 HA28 HB12 HB45 HB46 JA02 JA25 JA26 JB10 MA04 MA08 MA20 MB01 3J103 AA02 BA41 FA14 GA02 GA57 GA58 GA60 GA74 HA03 HA12 HA20 HA48 4F074 AA79 AA83 BA34 BC01 BC05 4J034 BA03 DB03 DB04 DB05 DC50 DG03 DG04 HA07 HC12 HC61 HC64 KA01 KB04 KB05 KD12 MA03 MA01

Claims (8)

[Claims] 1. A member made of a conductive polyurethane foam obtained by stirring and mixing a polyol, a polyisocyanate, an electrolyte, a foam stabilizer, a catalyst and water, wherein the foam stabilizer is represented by the following general formula (1): ] (Wherein, R ¹ is an alkylene group having 1 to 8 carbon atoms, R ² is a hydrocarbon group having 1 to 20 carbon atoms, EO is ethylene oxide, PO is propylene oxide, n is an integer of 1 to 5, a is Is an integer of 10 to 30, and b is an integer of 5 to 20.) 2. The conductive polyurethane foam member according to claim 1, wherein in the general formula (1), R ¹ is a trimethylene group. 3. The conductive polyurethane foam member according to claim 1, wherein the electrolyte is an alkali metal perchlorate. 4. The conductive polyurethane foam member according to claim 1, wherein the amount of the electrolyte is 0.3 to 3.5 parts by mass based on 100 parts by mass of the polyol. 5. The conductive polyurethane foam member according to claim 1, wherein the amount of the foam stabilizer is 0.5 to 2.5 parts by mass based on 100 parts by mass of the polyol. 6. The catalyst according to claim 1, wherein the catalyst is a tertiary amine.
The conductive polyurethane foam member according to any one of the above. 7. The conductive polyurethane foam member according to claim 1, wherein the conductive polyurethane foam member is a charging roller, a developing roller, a transfer roller, or a toner supply roller. 8. An image forming apparatus comprising the conductive polyurethane foam member according to claim 1.