JP2002361649A - Method for manufacturing polyurethane foam roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polyurethane foam roller which is of a low hardness with almost no hardness variability and has a good appearance, using a water foaming process. SOLUTION: The method for manufacturing a polyurethane foam roller comprises the steps of placing a shaft in a cylindrical mold, then casting a polyurethane stock into the mold and expand the stock using the water foaming process. The viscosity of the polyurethane stock is 10 to 5,000 mPa and the cream time is 5 to 10 seconds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a polyurethane foam roller used in an electrophotographic apparatus such as a copying machine, a facsimile, a printer, or an electrostatic recording apparatus, a polyurethane foam roller manufactured by the manufacturing method, and a method of manufacturing the same. The present invention relates to an image forming apparatus equipped with the rollers.

[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 for charging, developing,
Polyurethane members have attracted attention as members used for transfer, toner supply, cleaning, etc., and include a charging roller, a developing roller, a transfer roller, a toner supply roller,
An elastic roller such as a cleaning roller or an elastic blade such as a toner layer regulating blade or a cleaning blade is used. When the polyurethane member is used for an application that requires particularly low hardness, it is preferable to apply a polyurethane foam. A polyurethane member is produced by reacting and curing a liquid polyisocyanate component and a liquid polyol component. As a method for forming a polyurethane foam, a method of mechanically stirring gas while blowing gas such as nitrogen gas during the reaction curing (mechanical floss method), adding water to a polyol component, and adding water and a polyisocyanate component (Water blowing method), a method of adding a low-boiling liquid such as fluorocarbons and hydrocarbons to a polyol component, and evaporating the low-boiling liquid by raising the temperature during reaction curing. (Blowing agent floss method). The mechanical floss method is a manufacturing method in which the volume change during foam hardening is small.
It is a suitable method for obtaining a medium-hardness high-density foam having a hardness of 25 to 65 degrees and a density of about 0.3 to 0.8 g / cm ³ , and the water foaming method has an Asker F hardness of 30 to 100 degrees. This is a suitable method for obtaining a low-hardness low-density foam having a density of about 0.01 to 0.3 g / cm ³ . To produce polyurethane foam roller by mechanical floss method,
A metal shaft or the like may be arranged in advance, and a polyurethane material foamed by mechanical stirring may be cast into a metal mold having a preheated inner surface having a cylindrical shape, and may be cured by reaction. Also, cast polyurethane raw material into metal mold,
The reaction may be cured while adding mechanical stirring. In order to manufacture a polyurethane foam roller by a water foaming method, first, for example, a polyurethane material is poured into a mold having an inner dimension of 1 m × 1 m × 1 m to a height of about 0.1 m, and the material expands and expands and hardens as well. 1m × 1m
A polyurethane foam block of about × 1 m is obtained. Next, the obtained block is cut into a predetermined size,
A roller is manufactured through a process of making a hole, press-fitting a shaft, and cutting or polishing. However, when a roller is manufactured by such a manufacturing method, there is a problem that a large amount of grinding dust is generated by cutting or polishing. Further, when casting molding is performed using a cylindrical mold, there is a problem that the hardness of the polyurethane foam varies and a high hardness linear portion called a weld line is generated.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a method for producing a polyurethane foam roller having a low hardness, a small variation in hardness, and a good appearance by a water foaming method. The purpose is to do so.

[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, poured a polyurethane raw material into a cylindrical mold on which a shaft was placed, and then obtained the polyurethane material by a water foaming method. In producing a foam roller, it has been found that by optimizing the physical properties of the polyurethane raw material, a polyurethane foam roller having a low hardness, a small variation in hardness and a good appearance can be obtained. The present invention has been completed based on such findings. That is, the present invention is a method for producing a polyurethane foam roller by placing a shaft in a cylindrical mold, casting a polyurethane raw material, and foaming the polyurethane raw material by a water foaming method, wherein the viscosity of the polyurethane raw material is 10 to 5000 m.
The present invention provides a method for producing a polyurethane foam roller, wherein the Pa and the cream time are 5 to 10 seconds.

[0005]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, foaming of a polyurethane raw material is carried out by a water blowing method in which a foaming reaction proceeds simultaneously with a curing reaction. It does not include those containing air bubbles in advance. Polyols constituting polyurethane raw materials include polyether polyols obtained by addition polymerization of ethylene oxide and propylene oxide, polytetramethylene ether glycol, polyester polyols obtained by condensing an acid component and a glycol component, polyester polyols obtained by ring-opening polymerization of caprolactone, and polycarbonate. A diol or the like can be used. Polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide, for example,
Water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, methylglucode,
Starting from aromatic diamine, sorbitol, sucrose, phosphoric acid and the like, there can be mentioned those obtained by addition polymerization of ethylene oxide and propylene oxide.
Those starting from water, propylene glycol, ethylene glycol, glycerin, trimethylolpropane, and hexanetriol are preferred. As to the ratio of ethylene oxide to propylene oxide and the microstructure to be added, the ratio of ethylene oxide is preferably from 2 to 95% by mass, more preferably from 5 to 90% by mass.
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. The molecular weight of this polyether polyol is
When water, propylene glycol or ethylene glycol is used as a starting material, it becomes bifunctional and has a weight average molecular weight of 30.
It is preferably in the range of 0 to 6000, particularly 400 to 3
000 is preferred. When glycerin, trimethylolpropane, or hexanetriol is used as a starting material, the compound becomes trifunctional and has a weight average molecular weight of 900 to 900.
It is preferably in the range of 9000, particularly 1500 to 60
A range of 00 is preferred. In addition, a bifunctional polyol and a trifunctional polyol can be appropriately blended and used. In the present invention, in order to achieve the viscosity of the polyurethane raw material, the weight average molecular weight is 9000 or less, 3
It is preferable to use a polyether polyol having a functionality lower than the functionality.

Polytetramethylene ether glycol is obtained, for example, by cationic polymerization of tetrahydrofuran, and those having a weight average molecular weight of 400 to 4000, particularly preferably 650 to 3000 are preferably used. It is also preferable to blend polytetramethylene ether glycols having different molecular weights. Furthermore, polytetramethylene ether glycol obtained by copolymerizing an alkylene oxide such as ethylene oxide or propylene oxide can also be used. It is also preferable to use a blend of polytetramethylene ether glycol and a polyether polyol obtained by addition polymerization of ethylene oxide and propylene oxide.In this case, polytetramethylene ether glycol and addition polymerization of ethylene oxide and propylene oxide are used. The ratio with the polyether polyol is 95:
It is preferably used in a range of 5 to 20:80, and particularly preferably in a range of 90:10 to 50:50. Further, together with the polyol component, a polymer polyol obtained by modifying the polyol with acrylonitrile, a polyol obtained by adding melamine to the polyol, a diol such as butanediol, a polyol such as trimethylolpropane, or a derivative thereof can be used in combination.

The polyol may be pre-polymerized with a polyisocyanate in advance. The method is as follows. The polyol and the polyisocyanate are placed in an appropriate container and sufficiently stirred 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 raw material 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. Regarding the number of functional groups of polymeric diphenylmethane diisocyanate,
Although there is no particular limitation, a mixture of pure diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate having various functional groups is usually used, and the average number of functional groups is preferably 2.05 to 4.00, more preferably 2.0.
5 to 3.00 is 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.

Polyurethane raw materials include a conductive agent such as an electrolyte, a conductive material such as carbon black, a filler such as carbon black and inorganic carbonate, an antioxidant such as phenol and phenylamine, a low friction agent, and a charge control agent. Etc. can be added. Examples of the catalyst used for the curing reaction of the polyurethane raw material include monoamines such as triethylamine and dimethylcyclohexylamine; diamines such as tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexanediamine; pentamethyldiethylenetriamine, pentamethyldipropylenetriamine;
Triamines such as tetramethylguanidine, cyclic amines such as triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methyl Alcohol amines such as hydroxyethylpiperazine, hydroxyethylmorpholine, bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl)
Ether amines such as aminopropyl ether, stannas octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker, dioctyltin thiocarboxylate, phenylmercurypropion And organometallic compounds such as lead octenoate. These catalysts may be used alone or in combination of two or more.

In the present invention, it is preferable to blend a silicone foam stabilizer and various surfactants with the polyurethane raw material in order to stabilize the cells of the foam material. As the silicone foam stabilizer, a dimethylpolysiloxane-polyoxyalkylene copolymer or the like is preferably used and has a molecular weight of 35.
Those comprising a dimethylpolysiloxane moiety of 0 to 15000 and a polyoxyalkylene moiety having a molecular weight of 200 to 4000 are particularly preferred. The molecular structure of the polyoxyalkylene moiety is preferably an ethylene oxide addition polymer or a co-addition polymer of ethylene oxide and propylene oxide, and it is also preferable that the molecular terminal is ethylene oxide. Examples of the surfactant include cationic surfactants, anionic surfactants, ionic surfactants such as amphoteric surfactants, and nonionic surfactants such as various polyethers and various polyesters. The compounding amount of the silicone foam stabilizer and various surfactants is based on 100 parts by mass of the polyol.
It is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass. The mixing amount of the silicone foam stabilizer and various surfactants is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the polyol.

The cylindrical mold used in the production method of the present invention has a size necessary and sufficient for producing rollers used for charging, developing, transferring, supplying toner, cleaning and the like. Refers to mold. Specifically, for example, the roller outer diameter is 16.5 mm, and the roller length is 210.0.
When a roller having a diameter of 1 mm is manufactured, a hollow cylinder having an inner diameter of 16.5 to 20.0 mm and a length of 210 to 250 mm can be used as a mold. The mold used in the present invention includes metals such as aluminum, polyethylene,
Those made of synthetic resins such as polypropylene, polyethylene terephthalate, and polyvinyl chloride can be used. Among these, a synthetic resin mold is preferable because it is lightweight, easy to handle, and can be used repeatedly.

In the production method of the present invention, it is necessary that the viscosity of the polyurethane raw material is 10 to 5000 mPa and the cream time is 5 to 10 seconds. The viscosity of the polyurethane raw material is preferably 100 to 1000 mPa. As raw materials for obtaining polyurethane foam,
Usually, the viscosity is 10 mPa or more, and this viscosity is 500 mPa.
If it exceeds 0 mPa, it is difficult to uniformly inject the polyurethane raw material into the mold. If the injection is not performed uniformly, voids are generated and the surface of the roller becomes rough, resulting in a large variation in the hardness of the polyurethane foam. The cream time refers to the time from when water as a foaming agent is mixed with polyol and polyisocyanate until foaming (rise) is started. If the cream time is less than 5 seconds, it is difficult to uniformly inject the polyurethane raw material into the mold. If the cream time exceeds 10 seconds, the polyurethane raw material cannot be cured uniformly. In the present invention, the cream time is determined by weighing 50 g of a polyol in a 500 ml cup and adding an equivalent amount of polyisocyanate.
It is a value obtained by measuring the time required for starting foaming after high-speed stirring for 2 seconds.

In the manufacturing method of the present invention, the shaft is disposed in the cylindrical mold, and the foamed polyurethane raw material is cast therein, so that steps such as demolding, drilling, and press-fitting of the shaft after curing become unnecessary. A polyurethane foam roller can be obtained by performing finishing processing such as slight cutting and polishing as necessary, so that even when a small amount of various types of polyurethane foam rollers are produced, they can be manufactured at lower cost.

According to the production method of the present invention, the Asker F hardness is 3
This is a suitable method for obtaining a polyurethane foam having a low hardness and a low density of about 0.01 to 0.3 g / cm ³ at a density of 0 to 100 degrees. The obtained polyurethane foam roller is
The hardness variation is small, and the difference between the highest value and the lowest value of Asker F hardness is within 15 degrees. Examples of the polyurethane foam roller of the present invention include a charging roller, a developing roller, a transfer roller, a toner supply roller, and a cleaning roller. FIG. 1 is an explanatory view showing an example of an electrophotographic image forming apparatus in which a polyurethane foam roller of the present invention is mounted as a transfer roller, and shows an image forming body 1 holding a toner supply roller 3 and a latent electrostatic latent image. The transfer roller according to the present invention is disposed between the developing roller 2 and the image forming body 1 via a recording medium 8 such as paper. 5 shows a structure in which 5 is brought into contact. 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 toner jet printer, and the like.

[0016]

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, and the mixture was cast into a cylindrical acrylic mold having an inner diameter of 17.0 mm and a length of 250.0 mm. Inside the mold, a shaft coated with an adhesive and having an outer diameter of 6.0 mm and a length of 240 mm, which is obtained by plating zinc on sulfur free-cutting steel, is arranged. Then
The mold into which the foamed polyurethane raw material was cast was left in a hot air oven adjusted to 60 ° C. for 3 hours to cure the foamed polyurethane raw material. The cured polyurethane foam was removed from the mold, polished with a grindstone so that the outer diameter became 16.5 mm, and then both ends were cut to make the total length of the foam portion 210 mm, thereby producing a polyurethane foam roller. The density of polyurethane foam is 0.15g /
cm ³ (Example 1), 0.18 g / cm ³ (Comparative Example 1),
0.12 g / cm ³ (Comparative Example 2). When Asker F hardness was measured at three places of the polyurethane foam, it was found to be 64 to 71 degrees (Example 1), 52 to 75 degrees (Comparative Example 1), and 43 to 68 degrees (Comparative Example 2). The difference between the highest value and the lowest value of Asker F hardness obtained by the measurement was determined, and the variation in hardness was evaluated according to the following evaluation criteria.
That is, a case where the difference was within 10 degrees was rated as ○, a case where the difference was more than 10 degrees and 20 degrees or less, and a case where the difference was more than 20 degrees. Table 1 shows the results.

[0017]

[Table 1]

(Note) FA703: manufactured by Sanyo Chemical Co., Ltd., polyol (OH value: 3)
3) POP31-28: manufactured by Mitsui Chemicals, Inc., polyol (OH
Value: 28) diethanolamine: manufactured by Kanto Chemical Co., Ltd. Ketjen Black: manufactured by Ketjen Black International SRX274C: manufactured by Toray Dow Corning Silicone Co., Ltd., silicone foam stabilizer Kaorizer No. 31: Kao Corporation, tertiary amine catalyst 1: aliphatic tertiary amine catalyst manufactured by Kao Corporation Dabco BL19: manufactured by Sankyo Air Products T-80: manufactured by Sumitomo Bayern, tolylene diisocyanate

[0019]

According to the production method of the present invention, a polyurethane foam roller having a low hardness, a small variation in hardness and a good appearance can be produced by a water foaming method. In addition, even when a small amount of various types of polyurethane foam rollers are produced, they can be manufactured economically, so that an image forming apparatus equipped with the polyurethane foam rollers can be provided at low cost.

[Brief description of the drawings]

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

[Explanation of symbols]

 1: image forming body 2: developer carrying member 3: developer supplying member 4: developer layer forming blade 5: transfer member 6: cleaning member 7: charging member 8: recording medium

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G03G 15/08 501 G03G 15/08 501A 4J034 501D 15/16 103 15/16 103 21/10 B29K 75:00 // B29K 75:00 105: 04 105: 04 B29L 31:32 B29L 31:32 G03G 21/00 312 (72) Inventor Koji Achiba 1 Kashiocho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Bridgestone Yokohama Plant F-term (reference) 2H077 AA15 AC04 AD06 AD14 FA22 2H134 HA05 HA17 HA18 KD08 KD09 KE02 KH10 2H200 FA13 HA01 HA28 HB12 HB22 HB45 HB47 JA25 JA27 LC03 MA02 MA08 MC02 MC10 MC11 3J103 AA02 BA41 FA15 GA02 AD04 AGA04 GA04 AGA04 EA01 EB01 EB12 EK13 4J034 CA04 CA05 CB03 CB04 CB07 CC03 DA01 DB03 DB07 DG03 DG04 DG06 DG08 DG10 DG14 DG16 DG22 DQ0 5 DQ16 HA01 HA02 HA06 HA07 HB06 HB07 HB08 HB09 HC03 HC12 HC17 HC22 HC25 HC26 HC34 HC35 HC46 HC52 HC61 HC63 HC64 HC67 HC71 HC73 JA42 KA01 KB02 KC08 KC17 KC18 KD02 KD12 KD21 KE02 NA03 NA07 NA08 QA05 QC01

Claims (7)

[Claims] 1. A shaft is placed on a cylindrical mold,
A method of manufacturing a polyurethane foam roller by casting a polyurethane raw material and foaming by a water foaming method,
A method for producing a polyurethane foam roller, wherein the viscosity of a polyurethane raw material is 10 to 5000 mPa and the cream time is 5 to 10 seconds. 2. The method according to claim 1, wherein the polyurethane raw material contains a polyether polyol having a weight average molecular weight of 9000 or less and trifunctional or less in order to achieve the viscosity of the polyurethane raw material. 3. The method according to claim 1, wherein the mold is made of a synthetic resin. 4. The method according to claim 1, wherein the polyurethane foam has an Asker F hardness of 40 to 90 degrees. 5. A polyurethane foam roller produced by the production method according to claim 1. 6. The polyurethane foam roller according to claim 5, wherein the polyurethane foam roller is a charging roller, a developing roller, a transfer roller, a developer supply roller, or a cleaning roller. 7. An image forming apparatus comprising the polyurethane foam roller according to claim 5 mounted thereon.