JPH03214183A - Rubber roll - Google Patents

Abstract

PURPOSE:To obtain a rubber roll adaptable to mass production, and low in friction and free from adhesiveness by forming a layer made of polyorganosiloxane having specified F-containing groups at least on the outermost part. CONSTITUTION:At least the outermost layer is made of the polyorganosiloxane having polyperfluorooxyalkylene groups or perfluoroalkyl groups on the side chains. This polyorganosiloxane is prepared by substituting the polyperfluorooxyalkylene groups, that is, polyoxyalkylene groups obtained by replacing all the hydrogen atoms by F atoms, or the like for parts of the side chains of the polyorganosiloxane, usually used for the silicone rubber, such as polydimethylsiloxane or polymethylphenylsiloxane, thus permitting the obtained rubber roll to be adaptable for mass production and to have the surface low in friction and antitackiness.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rubber roll such as a fixing roll for a facsimile reading machine and an electrophotographic apparatus. More specifically, the present invention makes the surface of the rubber roll low-friction and non-adhesive, thereby making it possible, for example, in the case of the reading roll, to perform low-torque starting from a close contact with a glass image sensor. In the case of the fixing roll, it relates to a rubber roll that can prevent toner from adhering.

Conventional technology Rubber rolls such as reading rolls for facsimile machines, fixing rolls for electrophotographic devices such as electrostatic copying machines and laser printers, platen rolls for thermal printers, and various paper feed rolls include silicone rubber, chloroprene rubber, Ethylene propylene rubber etc. are used.

Among these, the facsimile reading roll uses a glass contact image sensor (hereinafter referred to as a glass plate) to read the document.
The rubber material used for this is silicone rubber or ethylene propylene rubber, but in small personal facsimile machines, the drive motor for paper feeding is also small and has low torque. If the rubber roll has a high coefficient of friction, the rubber roll and the glass plate will be in close contact with each other before the base paper is inserted, making starting rotation difficult. Therefore, a rubber roll with a low coefficient of friction is desired.

Furthermore, the fixing roll for electrophotographic devices is a heater roll that heats and presses PPC paper with a toner pattern on it to fix the toner into the paper fiber structure. However, since silicone rubber has poor toner release properties, it has the disadvantage that toner adheres to it and contaminates the PPC paper.

For this reason, taking advantage of the low friction and non-adhesive properties of fluororesin, consideration has been given to rubber rolls whose surface is coated with fluororesin or rubber rolls coated with fluororesin tubes. Attempts have been made to use tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, and tetrafluoroethylene-ethylene copolymers with improved properties.

However, in order to coat with fluororesin, the usual method is to apply a fluororesin solution to the surface of a rubber roll by brushing, dipping, spraying, etc., then drying and baking. 4. Chloroprene rubber wax has low heat resistance because it has to be heated at a high temperature of 300°C or more for a long time to crosslink the highly fluororesin. It cannot be applied to ethylene propylene rubber rolls, and even if silicone rubber rolls with good heat resistance are used, quality deterioration due to heat deterioration and heat shrinkage cannot be avoided, and the coating film is thin and lacks durability.
Moreover, there are drawbacks such as low yield when crosslinking and high cost.

On the other hand, in order to coat a silicone rubber roll with a fluororesin tube, the inner surface of the tube is roughened by an alkali treatment, etc., a silane coupling agent is applied, and then liquid silicone rubber is filled into the tube and cured. However, this method involves operational difficulties in pre-treating the inner surface of the tube and filling it with liquid silicone rubber, which inevitably lowers productivity.

As described above, conventional rubber rolls surface-treated with fluororesin are not necessarily satisfactory when used industrially.

Problems to be Solved by the Invention The present invention has been made with the object of overcoming the drawbacks of conventional rubber rolls, providing a rubber roll that is excellent in mass productivity, and has a low friction and non-adhesive surface. It is something.

Means for Solving the Problems The present inventors have conducted various studies to develop a rubber roll having a low friction and non-adhesive surface. It was discovered that the purpose could be achieved by forming a polyorganosiloxane layer, and based on this knowledge, the present invention was completed.

That is, the present invention provides a rubber roll characterized in that at least the outermost layer is formed of a polyorganosiloxane having a polyperfluorooxyalkylene group or a perfluoroalkyl group in its side chain.

The present invention will be explained in detail below.

The polyorganosiloxane having a polyperfluorooxyalkylene group or perfluoroalkyl group in the side chain used in the present invention is a polyorganosiloxane that is usually used as a silicone rubber, such as poly-
At least a portion of the side chains of polyorganosiloxanes such as dimethylsiloxane, poly-methylphenylsiloxane, poly-methylvinylsiloxane, and poly-methylphenylvinylsiloxane are polyperfluorooxyalkylene groups, that is, all of the hydrogen atoms of the polyoxyalkylene group. is a group in which is substituted with a fluorine atom, or a perfluoroalkyl group, that is, a compound in which all of the hydrogen atoms of an alkyl group are substituted with a fluorine atom, typical examples of which are: , general formula (in the formula, R7 is a polyperfluorooxyalkylene group or a perfluoroalkyl group, n2 and ns are 0 or 1
(nl and n are integers of 1 or more, m is O or an integer from 1 to 10). Further, as a typical example of R1 in this formula, polyperfluorooxyalkylene group is composed of alkylene having 2 to 4 carbon atoms and has 1 to 10 circulating units, such as polyperfluorooxyethylene group, polyperfluorooxyalkylene group, polyperfluorooxyalkylene group, etc. Fluoroquinbrobylele group, polyperfluorooxybutylene group, etc., and perfluoroalkyl groups having 2 to 20 carbon atoms, such as perfluoroethyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorooxybutylene group, etc. Examples include fluorohexyl group, perfluorooctyl group, perfluorodecyl group, and perfluorooctadecyl group.

These groups may be linear or branched. Particularly preferred are a group in which 2 to 5 moles of oxyhexafluoro-0-propylene groups are bonded, and a perfluorooctyl group.

Regarding this R group, in general, if a perfluoroalkyl group is selected, the physical properties will be bulky and rigid, while if a polyperfluorooxyalkylene group is selected, the physical properties will tend to be flexible, so select it appropriately depending on the purpose of use of the rubber roll. be done.

Until now, polyorganosiloxanes having partially fluorinated alkyl groups, that is, γ-trifluoropropyl groups (CF3CH2CH2), have been known as fluorine-containing polyorganosiloxanes, but the polyorganosiloxanes used in the present invention are Due to its high fluorine content compared to
It has excellent weather resistance, water absorption resistance, etc., as well as low friction and non-descaling properties.

The rubber roll of the present invention can be formed entirely of polyorganosiloxane having a polyperfluorooxyalkylene group or a perfluoroalkyl group in the side chain, but considering material cost, only the outermost layer is made of this fluorine-containing polyester. Advantageously, it is formed from an organosiloxane.

When the entire body is made of the above-mentioned fluorine-containing polyorganosiloxane, for example, a solid fluorine-containing polyorganosiloxane solid rubber is formed into a roll around a metal shaft by extrusion molding or press molding. After molding,
It can be manufactured by crosslinking and curing, or by molding liquid rubber into a roll around a metal shaft by injection molding and then crosslinking and curing.

In addition, in order to form the outermost layer with this fluorine-containing polyorganosiloxane, the fluorine-containing polyorganosiloxane solid rubber is extruded onto the surface of a rubber roll that has been previously formed from a material such as chloroprene rubber, silicone rubber, or ethylene propylene rubber. Either by laminating and crosslinking and curing by a molding method or press molding method, or by laminating a fluorine-containing polyorganosiloxane liquid rubber by an injection molding method on the surface of a preformed rubber roll and then crosslinking and curing, or by curing the surface of a preformed rubber roll. This can be carried out by applying a fluorine-containing polyorganosiloxane resin solution to the surface by brushing, dipping, spraying, etc., and curing it after drying.

The thickness of the fluorine-containing polyorganosiloxane layer formed by these methods is selected from a range of 1 to 2000 μm. If it is thinner than this, it will lack durability, and if it is too thick, it will be disadvantageous in terms of cost.

The crosslinking and curing of the above fluorine-containing polyorganosiloxane is as follows:
For example, this can be easily carried out by heating in the presence of chloroplatinic acid and peroxide.

The heating time is selected from the range of 1 to 10 minutes at 150 to 170'C and 5 to 20 seconds at 250 to 350C. In this way, crosslinking can be carried out even under relatively non-severe heating conditions, so in the present invention, not only materials with high heat resistance such as silicone rubber but also materials with low heat resistance such as chloroprene rubber and ethylene propylene rubber can be used. A rubber roll made of can also be used.

Effects of the Invention The rubber roll of the present invention has a fluorine-containing polyorganosiloxane layer with a very high fluorine content compared to conventional fluorosilicone rubber rolls having γ-trifluoropropyl groups (CCF3CH2CH2-) etc. in their side chains.
It has the remarkable effect of being able to maintain a low friction and non-adhesive surface layer that is at least comparable to conventional 77 resin coated rolls.

Moreover, since the fluorine-containing polyorganosiloxane of the present invention can be crosslinked under gentle heating conditions, it does not adversely affect the quality of the inner layer rubber roll, and it is not a silicone rubber roll, but a heat-resistant material such as chloroprene rubber or ethylene propylene rubber. It is industrially advantageous because it can be applied to low-quality rubber rolls, mass production is possible, and the yield is high.

Example Next, the present invention will be explained in more detail with reference to Examples.

In addition, the frictional force and adhesiveness in each example were measured as follows.

(1) Hold the friction crab test roll horizontally, and place a long thin PPC paper (Xerox L paper, 20X 100mm) on its surface perpendicular to the axial direction, with approximately half of the long sides oriented horizontally and the rest vertically. A 20hf weight was suspended from one end, a tension gauge was connected to the other horizontal end, and this tension gauge was pulled at a speed of 100 mm/min. The scale (gf) of the gauge was read and used as the frictional force.

(2) Adhesiveness: Place the roll to be tested horizontally and apply black toner (manufactured by Fuji Xerox Co., Ltd., trade name B 228) on top.
) was deposited in a heap, the black toner was shaken off, and the presence or absence of adhesion on the surface was observed.

Example 1 Solid silicone rubber with hardness of 70°Hs (JIS-A)
100 parts by weight of peroxide crosslinking agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name KE-9710), product name C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.)
) and 7 parts by weight of a white pigment (manufactured by Shin-Etsu Polymer Co., Ltd., trade name: Color W) to form a rubber roll with a diameter of -18 mm and a length of 230 mm. Next, a polyorganosiloxane liquid rubber (manufactured by Shin-Etsu Chemical Co., Ltd., trade name:
7O-4000) 100 parts by weight, dicumyl peroxide (manufactured by Shin-Etsu Chemical Co., Ltd., trade name C-3) 1.5 parts by weight,
Chloroplatinic acid catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., trade name CAT-P
L-2) 0.04 parts by weight, control agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name R-153A), 0.1 part by weight, methylhydrodiene polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name C)
-153A) Rubber compound B consisting of 2 parts by weight was mixed and kneaded, and two-layer coextrusion molding method (crosslinking conditions, 350°C
05ec), the diameter I with a coating of thickness l+im
A two-layer rubber roll of 20 mm x length 230 m+i was molded.

When the frictional force of this material was measured, it was 240 gf. In terms of tackiness, no toner residue was observed at all.

For comparison, the frictional force and adhesion were measured for a rubber roll made only of Compound A without coating of Compound B. The frictional force was 9509'', and toner adhesion was observed.

Example 2 A silicone rubber roll with a diameter of 118 mm and a length of 230 + i + i was manufactured using compound A of Example 1 L f
-0 This was placed in a mold, and its surface had a hardness of 60°Hs (JIS-A
) polyorganosiloxane liquid rubber (manufactured by Shin-Etsu Chemical Co., Ltd., trade name X-70-301) was applied by injection molding, crosslinked and cured to a thickness of 1. Diameter with X-70301 layer as outer layer in mm! A two-layer rubber roll measuring 20 mm x 230 mm in length was obtained.

The friction force of the rubber roll obtained in this way is 350
Although the gf value was slightly higher than that of Example 1, no toner adhesion was observed as a result of the toner adhesion test.

Example 3 A silicone rubber roll having a diameter of -20 mm and a length of 23 km was manufactured using Funpound A of Example 1.

Next, a resin solution with a viscosity of 5 centistokes (manufactured by Shin-Etsu Chemical Co., Ltd.,
A solution containing 100 parts by weight of 100 parts by weight of the product (trade name: After preparing a solution dissolved in 100 parts by weight of FR thinner, the rubber roll was immersed in this solution, air-dried for 30 minutes or more, and cross-linked under the conditions of 180°C I got a rubber roll.

The friction force of the rubber roll thus obtained was measured and found to be 250 gf.

On the other hand, for comparison, a liquid silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd., product name KEL34O) was attached to a PFA tube (manufactured by Gunze Co., Ltd.) with a thickness of 50 μm x inner diameter I20 mm x length 230 mm.
The thickness of the fluororesin-coated rubber roll and fluororesin coating agent (manufactured by Nippon Acheson Co., Ltd., trade name: 1063 Clear) injection molded A/B) is 1OllI.
Diameter 120mm x length 230mm with I+ hardened film formed
When ethylene propylene rubber rolls having a diameter of 2 mm were prepared and the frictional force was measured in the same manner as in the above example, the former had a friction force of 220 gf, and the latter had a friction force of 240 gf. Further, as a result of the toner adhesion test, no toner adhesion was observed.

Claims (1)

[Claims] 1. A rubber roll comprising at least the outermost layer formed of a polyorganosiloxane having a polyperfluorooxyalkylene group or a perfluoroalkyl group in its side chain.