JP2543859B2 - Silicon rubber roll - Google Patents

Description

TECHNICAL FIELD The present invention relates to a silicon rubber roll having a silicon rubber layer on a metal cored bar.

[Conventional technology]

This type of silicone rubber roll has heat resistance, chemical resistance, elastic properties that hardly change at high temperature, surface sliding property of silicone rubber itself,
It is used in many industries due to its non-stick property.

Especially with the spread of OA equipment, silicone rubber rolls
It is widely used for fixing rolls for copiers, paper feed rolls, printer rolls for computers, fixing rolls for laser printers, etc., but the recent advances in OA equipment technology are remarkable, and in this type of field, durability Silicone rolls, which are more excellent in heat resistance and releasability, have higher strength, and are more non-adhesive, have been required.

Therefore, by coating the surface of the silicone rubber roll with a fluororesin, it is attempted to add the excellent properties such as chemical resistance, heat resistance, electrical insulation, self-lubrication, and non-adhesiveness of the fluororesin to the silicone rubber roll. Attempts have been made to do so.

[Problems to be Solved by the Invention]

By the way, since silicone rubber and fluororesin are materials having excellent non-adhesiveness and basically cannot be adhered to each other, conventionally, an adhesive force has been applied to the boundary surface between the silicone rubber layer and the fluororesin layer. The pliers for strengthening and an intermediate material such as a reinforcing material are interposed, or another material is mixed with the fluororesin to bond them.

However, interposing an intermediate material between the silicone rubber layer and the fluororesin layer may impair the original flexibility and elasticity of the silicone rubber roll. Further, when other materials are mixed with the fluororesin, there is a problem that the original characteristics of the fluororesin are impaired.

Further, in the use of printing machines and OA equipment, the adhesion between the silicone rubber layer and the fluororesin layer requires a peel strength of at least 130 g / 20 mm width or more, but the conventional method provides the desired peel strength. There was a problem of not having.

Therefore, the present invention is intended to obtain a silicone rubber roll having a fluororesin layer directly on the silicone rubber layer and having high peel strength between the silicone rubber layer and the fluororesin layer.

[Means for solving the problem]

This invention controls the amount of the filler to be dispersed and mixed in the silicone rubber layer and the thickness of the fluororesin layer, so that the silicone rubber layer and the fluororesin layer can be bonded to each other without using a primer or an adhesive at the interface. The adhesion between the rubber layer and the fluororesin layer is improved.

The silicone rubber layer and the fluororesin layer are firmly adhered to each other, and the high peel strength is obtained. The amount of the filler in the silicone rubber layer is 50% by weight or more and 90% by weight or more based on the total amount of the rubber layer.
Is less than. The thickness of the fluororesin is in the range of 6 to 24 μm.

The fluororesin layer is provided by directly coating the surface of the silicon rubber layer with an unsintered fluororesin, and then heating and firing at a temperature equal to or higher than the melting point of the fluororesin.

〔Example〕

The metal core bar used in the present invention includes, for example, a pipe made of aluminum, iron, stainless steel or the like whose surface is surface-treated by a method such as sandblasting or polishing.

A silicon rubber layer is provided on the surface of the metal core bar as follows. First of all, apply a primer to a metal core bar, and put the metal core bar wound with silicon compound on the surface by a method such as extrusion method, processing method, hand winding method, etc., put it in a vulcanization pot and vulcanize it, and further about 200 ° C After vulcanizing again in the furnace, the surface is polished and finished to the diameter as specified.

The silicone rubber compound is, for example, mixed with silica powder in an amount equal to or almost the same as that of silicon raw rubber, and further added in small amounts such as red husk, vulcanizing agent, manganese, etc. so that the amount becomes larger than the amount of silicone resin. Optimally, it should be kneaded so that it is 55% (wt%) or more.

The filler mixed with the silicone raw rubber, for example,
Silica, iron oxide, manganese, cobalt, alumina curing agent, vulcanizing agent, etc. are included, so that the total amount is at least a proportion of silicone raw rubber, that is, at least 50% by weight, especially,
In order to improve the adhesiveness with the fluororesin layer, the amount is 55 to 90% by weight. The amount of filler is 90
If it is more than weight%, it will not become silicone rubber.

Next, on the surface of the silicone rubber layer formed as described above, an unbaked fluororesin, such as tetrafluoroethylene resin, tetrafluoroethylene-perfluorovinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene. A resin such as an enamel, a dispersion and a powder such as a copolymer is applied by a method such as spraying, tepping and powder coating so as to have a film thickness of 6 μm to 24 μm.

Thereafter, the temperature of the unsintered fluororesin layer is equal to or higher than the melting point of the fluororesin, that is, 327 ° C. in the case of tetrafluoroethylene resin, 306 ° C. in the case of tetrafluoroethynylene-perfluorovinyl ether copolymer. In the case of a tetrafluoroethylene-hexafluoropropylene copolymer, the fluororesin layer is baked by heating at a temperature of 280 ° C or higher.

The composite roll of the metal cored bar, the silicone rubber layer and the fluororesin layer thus obtained shows a slightly shiny luster covered with the surface layer of the baked fluororesin layer and has a heat resistance of 220 ° C.
Withstands temperatures of ℃ and shows releasability, it is a very suitable roll for printing machines and fixing rolls for OAB equipment.

The following table shows the relationship between the amounts of silicone raw rubber and other fillers in the silicone rubber layer and the adhesiveness (peel strength) of the fluororesin coating.

When used as a fixing roll in OA equipment, the peel strength between the silicone rubber layer and the fluororesin layer is at least 130g / 20m
A width of m or more is required, and life of 130g / 20mm or less is a problem in terms of life. Further, the above table shows that the adhesiveness increases as the amount of the filler increases, but when 90% or more of the filler is contained, the silicone rubber roll cannot be used. Also, from the characteristics of silicone rubber, it is most suitable for use as a printing machine roll and a fixing roll for OA equipment when the amount of filler contained in the silicone rubber is 55-80%. If the film thickness is 30 μm, the peel strength becomes weak and it is not suitable for use.

Example 1 An aluminum roller was trial-produced with a roll effective surface length of 300 mm, a diameter of 30 mmφ, and bosses into which bearings are inserted at both ends, and the effective surface was surface-treated with Sandplast ^# 600.

Next, Toray Silicone Co., Ltd., silicon 40% (wt%) is mixed with silicon raw rubber, and 4% (wt%) of Magne powder and 15% (wt%) of red moth are mixed with several% of vulcanizing agent. Then
A kneading machine was used to obtain a viscous silicon compound.

The silicon compound thus obtained was coated with a primer on the surface of an aluminum cored bar, and was further hand-rolled to form a film having a thickness of about 3 mmt. Further, this product was left in a steam vulcanizer 160 ° C. for about 6 hours and then taken out, and then left again in an electric furnace at 220 ° C. for 4 hours and taken out. Then, the surface of the silicone rubber roll was polished to a predetermined size.

10 mg of the silicon rubber layer of the roll wrapped with the silicone rubber thus obtained was scraped off, and the temperature was adjusted to 600 ° C. with a differential thermal balance.
After heating until the silicon component was decomposed and blown off, the residue was examined and found to be 68% and 32% silicoresin.

The surface of the silicone rubber roll thus obtained was spray-coated with enamel tetrafluoroethylene resin to a film thickness of about 15 μm and dried at 180 ° C. for about 10 minutes. Later, when heat was applied to the tetrafluoroethylene resin coating at 327 ° C or higher, the white unfired tetrafluoroethylene resin film became transparent, and the red color of the underlying silicon rubber clearly emerged. A fixing roll for a copying machine, which was covered with a resin and showed luster, had a silicon rubber layer on an aluminum core metal, and further had a baked tetrafluoroethylene resin layer was obtained. One of the rolls thus obtained was crushed for a destructive test and the adhesion of the tetrafluoroethylene resin coating was measured with a width of 20 mm. The peel strength was 230 g and the film thickness was 15 μm. As a result of putting this roll in a copying machine and performing a durability test, it was found that the tetrafluoroethylene resin film did not peel off even after passing 200,000 sheets of paper, and that it was very suitable as a fixing roll for copying machines. all right.

[Comparative Example 1] A composite roll was prototyped by the same method as in Example 1, the amount of silicon raw rubber in the silicon rubber was increased, and the value of the differential thermal balance obtained by the same method as in Example 1 was 48%, that is, silicon raw rubber. A roll having an amount of 52% was prototyped, and the other conditions were exactly the same as in Example 1. The peel strength between the tetrafluoroethylene resin coating of this roll and the silicone rubber layer was measured to be 60g / 20
It was mm width. The roll thus obtained was set in a copying machine, and a durability test was carried out on an actual machine.When approximately 15,000 sheets were passed, the tetrafluoroethylene resin coating partly floated from the silicone rubber layer, causing white spots and durability. It turned out that there was no sex.

[Comparative Example 2] Similar to Example 1, the thickness of the tetrafluoroethylene resin coating was set to 5 μm, and the same as in Example 1 except that the peel strength of the tetrafluoroethylene resin coating was 200 g. Although it was good, it was found that when applied to an actual machine, offset occurred after passing about 20,000 sheets, and there was a problem in releasability.

Example 2 A stainless steel core 60 mmφ roll was prepared, the surface was sandblasted, and then 75% of a filler such as silica, quartz, alumina, carbon, and a vulcanizing agent was added to silicon raw rubber, and kneaded. A silicone rubber roll similar to that of Example 1 was obtained by using. The color was black. Powder of tetrafluoroethylene-perfluorovinyl ether copolymer is applied to this silicone rubber roll to a thickness of about 20 μm, and then powder of tetrafluoroethylene-perfluorovinyl ether copolymer is melted. Then, it was baked by heating to cover the fluororesin film. The peel strength between the fluororesin layer and the silicone rubber layer of the roll thus obtained was 230 g / 20 mm width, and it was found in an actual machine durability test that it had more than 200,000 sheets and was suitable for a fixing roll and a printing roll.

〔The invention's effect〕

As described above, the silicone rubber roll of the present invention, in which the fluorocarbon resin layer is directly coated on the silicone rubber layer, and since the peeling strength between the silicone rubber layer and the fluorocarbon resin layer is high, particularly, the fixing roll of the copying machine, It can be suitably used for printing rolls.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 61-158361 (JP, A) JP 61-89845 (JP, A) JP 61-84670 (JP, A) JP 58- 51262 (JP, B2)

Claims (2)

(57) [Claims] 1. A silicone rubber roll having a silicone rubber layer on a metal core, wherein the amount of the filler in the silicone rubber layer is 50% by weight or more and less than 90% by weight based on the total amount of the rubber layer. A silicon rubber roll having a fluororesin layer having a thickness of 6 to 24 μm, which is obtained by directly coating an unsintered fluororesin on the surface of and heating and firing. 2. The fluororesin is tetrafluoroethylene resin,
The silicone rubber roll according to claim 1, comprising one of a tetrafluoroethylene perfluorovinyl ether copolymer and a tetrafluoroethylene hexafluoropyropyrene copolymer.