KR20050114043A - Method for preparing an electro-conductive rubber roller - Google Patents

Abstract

The present invention relates to a method for producing a conductive rubber roller, specifically, the step of dispersing a conductive polymer material and a crosslinking agent; Aging step; Extrusion step; Crosslinking step; Cutting and adjusting the outer diameter and surface roughness; Foreign material removal step; Ultraviolet treatment and volatilization of residual organics; And confirming the appearance, resistance and dimensions of the conductive rubber roller, wherein the crosslinking is performed by passing the extrudate in the extrusion step through a chamber filled with solid particles. It relates to a method for producing a conductive rubber roller. According to the present invention, while maintaining the advantages of the existing extrusion method as it is, without the continuous continuous crosslinking operation, by adopting a continuous crosslinking method immediately after extrusion, to eliminate the risk of the kiln work of high temperature and high pressure, The roller of uniform quality can be manufactured, and the manufacturing method of the conductive rubber roller which can shorten a production yield and time can be provided.

Description

Method for preparing an electroconductive rubber roller

The present invention relates to a method for manufacturing a conductive rubber roller used in an electrophotographic image forming apparatus. Specifically, the present invention relates to a method of manufacturing a conductive rubber roller. By adopting the formula crosslinking method, it is possible to eliminate the risks associated with the operation of the kiln at high temperature and high pressure, to produce a roller of uniform quality, and to significantly reduce the production yield and time. It is about.

In general, the conductive rubber roller used in the electrophotographic image forming apparatus should be: i) low hardness to obtain a suitable nip width, ii) the conductive roller being contacted will not be permanently deformed, i) electric resistance 10 ⁵ In the semiconductor region of ¹⁰ to 10 kPa, i) excellent in abrasion resistance and durability, i) no transfer from the developing roller to the photosensitive member, i) desired charging polarity and charge amount by friction with the toner To be obtained, i) good releasability with toner, no toner filming on the surface of the developing roller during use, and iii) the surface should have a suitable surface roughness to obtain a uniform toner layer on the surface of the developing roller. It needs characteristics such as to have.

As a method for producing a conductive rubber roller having the above properties, conventionally, an extrusion method and a press method have been commonly used.

1 schematically shows a manufacturing process of the conductive rubber roller by the extrusion method. Referring to Figure 1, the forming and processing steps of the conductive rubber roller by extrusion may include the steps of: i) cutting and metering raw rubber and chemicals, ii) compounding, i) aging, i) extrusion, i) Curing, (i) cutting, (i) polishing, (i) cleaning, (i) UV treatment, and (i) inspection are performed.

In step iii), a conductive polymer such as rubber and a crosslinking agent are selected according to a predetermined formulation table. In step ii), a mixer such as an open roller, a kneader or a Banbury mixer is selected. To uniformly disperse the material, and in step iii), aged at room temperature for a certain period of time to recover the tangled structural arrangement in the compounding step, and in step iii) to minimize the effects of high viscosity of the rubber and heat damage of the additives. In order to perform low temperature extrusion with a single screw or twin screw extruder, in step iii), by adding heat alone or by applying heat and pressure, the added crosslinking agent is decomposed to form a three-dimensional network structure so as to give elasticity to the high-viscosity liquid phase and solidify. In the step of cutting to the size of the desired product, in step iii) the outer diameter and surface roughness of the product In step iii), foreign matters on the outside of the roller generated during the process are removed, and in step iii), UV treatment is performed to lower the surface friction force and volatilize residual organic substances. Check the appearance, resistance and dimensions.

Another conventional technique for manufacturing a conductive rubber roller is a press method, and Fig. 2 schematically shows a manufacturing process of the conductive rubber roller by the press method. Referring to Figure 2, the forming and processing steps of the conductive rubber roller by the press method, i) cutting and metering of raw rubber and chemicals, ii) compounding, v) curing, v) cutting, v A) grinding, v) cleaning, v) UV treatment, and v) inspection, and a similar process to extrusion, except that the aging and extrusion steps are omitted.

In the prior art, the manufacture of the conductive rubber roller by the extrusion method requires a lot of man-hours because each series of processes such as kneading, extrusion, crosslinking, polishing, etc. of raw materials is required, and the kiln process is essential as a separate process. The disadvantage is that it must proceed. That is, the conductive compound is introduced into the extruder, and the compound compressed in the cylinder is first molded through a cross die, and the first molded product is transferred to a standardized shelf, and then placed in a closed space at an average pressure of 4 kg / cm ² or more. The roller which maintains elasticity is produced by making it react at the temperature more than degreeC. However, the molding process and the crosslinking process must be performed separately, resulting in excessive time and manpower input costs between the pretreatment and the post-treatment, resulting in an increase in product defects, thereby causing a price increase. .

In addition, unlike the extrusion method, the production of the conductive rubber roller by the press method does not require a separate extrusion process, and since the crosslinking operation can be performed simultaneously with the molding, the workability is easy, the manufacturing time is shortened, and the cost is reduced. There is an advantage over the extrusion method. However, high temperature and high pressure must be applied to mold the compound in the mold, and this high pressure can deflect the metal shaft and result in deformation of the roller. In addition, there is a problem that the product value is lowered by causing a partial resistance unevenness to leave a trace in the upper and lower plate joint portion of the molding.

The technical problem to be achieved by the present invention, while maintaining the advantages of the existing extrusion method, without adopting a non-continuous separate cross-linking operation, by adopting a continuous cross-linking method immediately after extrusion, there is a risk of high temperature and high pressure kiln work It is to provide a method of manufacturing a conductive rubber roller that can remove the, to produce a roller of uniform quality, and can greatly shorten the production yield and time.

In order to achieve the above technical problem, the present invention in one aspect,

Uniformly dispersing the conductive polymer material and the crosslinking agent using a mixer;

Aging at room temperature;

Extruding by an extruder;

Continuously crosslinking by passing through a crosslinking zone;

Cutting and adjusting outer diameter dimensions and surface roughness;

Removing foreign matter generated during the steps;

Performing ultraviolet treatment to lower the surface friction and volatilize residual organics; And

In the manufacturing method of the conductive rubber roller comprising the step of checking the appearance, resistance and dimensions of the completed conductive rubber roller,

The crosslinking is carried out by passing the extrudate in the extrusion step through a chamber filled with solid particles, thereby providing a method for producing a conductive rubber roller.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a method for manufacturing a conductive rubber roller used in an electrostatic recording device such as a printer, a fax machine, a copier, etc., while maintaining the advantages of the conventional extrusion method, the crosslinking reaction is carried out immediately after extrusion to obtain a high temperature and high pressure. The present invention relates to a method for manufacturing a conductive rubber roller, which can eliminate the risks associated with kiln work, to produce rollers of uniform quality, and to enable continuous mass production. In other words, the method for producing a conductive rubber roller according to the present invention is continuously cut in a short time by eliminating the process of separately performing the crosslinking reaction for a long time by applying a high temperature and high pressure after cutting the rollers individually and extrusion into the kiln for crosslinking reaction. Mass production of food is possible. In addition, since the crosslinking can be performed simultaneously with molding, uniform quality can be obtained and a low-cost product can be produced in which the defective rate is reduced due to the shortening of the man-hour.

Conductive rubber rollers used in electrostatic recording devices, such as printers, fax machines, copiers, etc., mix a base material on rubber with a mixture of peroxide alone or with other crosslinking agents and add heat alone or external energy such as heat and pressure. It can manufacture by adding. At this time, the unstable portion of the crosslinking agent takes a hydrogen atom in the rubber main chain or branched chains thereof so that the crosslinking agent itself is stabilized and the rubber main chain or branched chains undergo a continuous reaction, thereby producing an elastic body having a three-dimensional network crosslinked structure. Done.

In general, as a crosslinking agent of elastomers having a low T _g value such as rubber, sulfur-containing materials have been used that exhibit stable properties even at room temperature. Sulfur is insoluble and odorless, imparts elastic properties to the crosslinked product, and has a high reaction temperature, which makes it easy to handle even at the kneading temperature of the rubber.

However, since the temperature at which the ring-opening reaction occurs for sulfur to perform its function as a crosslinking agent is 180 ° C. or higher, high energy is required and the reaction time is slow and the reaction time is long. In addition, when the amount of addition or the reaction conditions are different, there is a problem that the unreacted residue may be exposed to the surface of the roller may cause deterioration of the product.

On the other hand, since the sulfur of the octagon structure reacts with the rubber chains to form a three-dimensional network structure, heat is inevitably required in order to give elasticity to the rubber and to act as a roller. React to form a network structure. Means for providing this heat to sulfur include various heat sources as follows.

Iii) steam

In the case of steam crosslinking, which is most widely used in the rubber industry, it is required to react for a long time under high temperature and high pressure for sufficient sulfur reaction. In addition, the extruded uncrosslinked rollers are required to be individually manufactured individually in order to be put in a kiln of a limited space. Therefore, a separate cutting operation is involved, and a predetermined reaction time is required for preheating the kiln before the kiln addition and cooling for the next step after the crosslinking reaction. In addition, high pressure conditions are required for shortening the crosslinking time and performing the process efficiently, but this makes the process very dangerous.

Ii) thermal medium

A method of using a thermal medium such as Dowthern, which is very expensive and is only used for some special applications.

Iii) thermal air

In the case of a closed type by a double vulcanizing tube, a significant pressure of hot air is injected to prevent sagging of the rubber, and to minimize the quality deviation by equalizing the temperature above and below. However, this method also has inefficient aspects such as the rubber surface is easy to oxidize or age, crosslinking time is more than 1 hour.

Heat transfer

In the case of the heating method by electric heat, there is no need for a boiler and piping, heat loss is low, high temperature is easily obtained, it is easy to adjust. However, when the temperature distribution is uneven and the thickness of the rubber is thick, there is a disadvantage that the degree of crosslinking inside and outside is different.

기타) Other

And a method of crosslinking the extrudate by infrared irradiation or high frequency heating.

In the present invention, a crosslinking method using solid particles is used, and the crosslinking method enables the continuous crosslinking immediately after extrusion without performing any discontinuous separate crosslinking operation while maintaining the advantages of the conventional extrusion method. It eliminates the risk of kiln operation at high temperature and high pressure, can produce rollers of uniform quality, and can greatly reduce production yield and time.

The solid particles are not limited as long as they are materials capable of forming a kind of solid particle smoke film, but are preferably glass beads, metal beads, sand, or mixtures thereof.

Preferably, the drying air of 180 to 230 ℃ is introduced in the lower portion of the chamber filled with the solid particles.

Further, preferably, the particle diameter of the solid particles is 0.01 to 5 mm.

If the temperature of the dry air and the particle diameter of the solid particles are outside the above range, partial vulcanization or local unvulcanization may occur, which is not preferable.

In the present invention, the solid particles as described above are placed in a narrow and long tube, and a dry hot air is introduced from the bottom to form a state similar to that of a heating vessel, that is, a liquid volatilization, such as a smoke screen of solid particles. By such a heating bath, it is possible to provide a heat medium having a thermal conductivity of about 50 times that of simple heating air.

Conductive polymer materials that can be used in the conductive rubber rollers according to the present invention include acrylonitrile butadiene rubber, epichlorohydrin rubber, ethylene-propylene diene rubber, styrene butadiene rubber, ethylene propylene rubber, acrylonitrile butadiene isoprene rubber and these And mixtures thereof. Among these, epichlorohydrin rubber is excellent in compatibility with an acrylonitrile butadiene rubber.

In addition, it is preferable that epichlorohydrin rubber uses the ternary copolymer of ethylene oxide, allyl glycidyl ether, and epichlorohydrin, or the binary copolymer of ethylene oxide and epichlorohydrin.

In addition, crosslinking agents commonly used in the art may be used in the conductive rubber roller according to the present invention, and non-limiting examples of such crosslinking agents include dicumyl peroxide, t-butyl peroxyhexane, benzoyl peroxide or t. Organic peroxides such as butyl peroxybenzoate; brimstone; Thiuram polysulfite; Polyamines such as ethylene diamine, diethylene triamine, triethylene tetraamine, hexamethylene tetraamine or ethylene diamine carbamate; Thioureas such as 2-mercapto imidazoline, 1,3-diethyl thiourea, 1,3-dibutyl thiourea or trimethyl thiourea; And mercaptan triazines such as 2,4,6-trimercapto-1,3,5-triazine or 1-methoxy-3,5-dimercaptotriazine.

In addition to the conductive polymer material and the crosslinking agent, if necessary, a conductive filler, an anti-aging agent, a crosslinking accelerator, and the like may be further included.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

Example 1

50 parts by weight of acrylonitrile butadiene rubber containing 25% acrylonitrile and 50 parts by weight of a hydrin rubber mixture in which epichlorohydrin, ethylene oxide and arylglycidyl ether are mixed in a weight ratio of 40: 56: 4, respectively. The molten rubber is first melted in a preheated Banbury mixer, removed and transferred to an open roller, and then 7 parts by weight of carbon black, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 2, 0.5 parts by weight of 2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ), 1 part by weight of dicumyl peroxide and 20 parts by weight of diallylphthalate were added to disperse uniformly. Aged for 24 hours at room temperature, and then extruded into a tube at 80 ~ 90 ℃ by single or twin screw extruder. For the extrudate, vulcanization was carried out by filling glass tubes filled with glass beads with an average particle diameter of 0.2 mm and passing dry air at 180 ° C. from the bottom. The obtained vulcanized rubber tube was heat-bonded to the outer circumferential surface of a shaft made of sus material having a diameter of 6 pies and a length of 26 cm using chemlock as an adhesive. Adjust the outer diameter of the obtained conductive rubber roller to 14 pies, adjust the surface roughness to 2 to 3, lower the surface friction coefficient to 0.1 to 0.3 by ultraviolet irradiation, and then check the appearance, resistance and dimensions of the finished conductive rubber roller. A conductive rubber roller was produced.

According to the present invention, while maintaining the advantages of the existing extrusion method as it is, without the continuous continuous crosslinking operation, by adopting a continuous crosslinking method immediately after extrusion, to eliminate the risk of the kiln work of high temperature and high pressure, The roller of uniform quality can be manufactured, and the manufacturing method of the conductive rubber roller which can shorten a production yield and time can be provided.

1 is a view showing a schematic process diagram for the extrusion method as a method of manufacturing a conductive rubber roller according to the prior art.

Figure 2 is a view showing a schematic process diagram for the use of the press as a method of manufacturing a conductive rubber roller according to the prior art.

Claims (4)

Uniformly dispersing the conductive polymer material and the crosslinking agent using a mixer; Aging at room temperature; Extruding by an extruder; Continuously crosslinking by passing through a crosslinking zone; Cutting and adjusting outer diameter dimensions and surface roughness; Removing foreign matter generated during the steps; Performing ultraviolet treatment to lower the surface friction and volatilize residual organics; And In the manufacturing method of the conductive rubber roller comprising the step of checking the appearance, resistance and dimensions of the completed conductive rubber roller, The crosslinking is carried out by passing the extrudate in the extrusion step through a chamber filled with solid particles. The method of claim 1, wherein the solid particles are glass beads, metal beads, sand, or a mixture thereof. The method of claim 1, wherein the lower part of the chamber filled with the solid particles, the drying air of 180 to 230 ℃ flows. The method for producing a conductive rubber roller according to claim 1, wherein the particle diameter of the solid particles is 0.01 to 5 mm.