JPS5925884B2 - rubber roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in rubber rollers, particularly relatively small diameter rubber rollers such as paper feed rollers and platen rollers in office equipment, or pinch rollers in tape recorders and the like.

Conventionally, this type of roller is required to have a considerable degree of hardness (JIS hardness 700 or higher) due to its use, so it has a considerable amount of It is made from a rubber composition containing 50 parts by weight or more of carbon black, silica, magnesium carbonate, and other inorganic reinforcing fillers.

Therefore, the Mooney viscosity of the unvulcanized rubber composition is extremely high (usually ML0T4 (100°C) ≧50),
Distortion of the metal core occurs during vulcanization molding of the roller, and after molding,
As the core returns to its straight state, the rubber roller portion on the outer periphery becomes distorted. This deformation is not so noticeable in appearance, but since the external dimensional accuracy allowed for this type of rubber roller is within 0.05 mwl, the outer peripheral surface is usually subjected to para-machining after vulcanization is completed. is being carried out. On the other hand, in order to suppress the above-mentioned increase in Mooney viscosity, there is a method known in rubber processing technology of mixing softeners, thermoplastic resins, processing aids, etc. This method is not suitable for this type of roller because it bleeds onto the rubber surface during use, causing problems such as surface adhesion, changes in the coefficient of friction, and contamination of the paper surface. It is an object of the present invention to eliminate the above-mentioned drawbacks, and to provide a rubber roller that does not cause any inconvenient distortion of the metal core during vulcanization molding, and therefore has extremely uniform external dimensional accuracy in the finished roller. The gist of this method is to make the rubber roller using a rubber composition made of natural rubber, butadiene rubber, or a mixture thereof, which is blended with a reactive reinforcing filler instead of the conventional inorganic reinforcing filler.

Examples of the reactive reinforcing filler used in the present invention include zinc methacrylate and polyfunctional monomers such as trimethylolpropane and trimethacrylate.

As described below, these reinforcing fillers do not increase the Mooney viscosity of the unvulcanized rubber composition and provide the finished rubber roller with the required high hardness, but they also provide stronger adhesion to the metal core. When required, it is preferable to use zinc methacrylate;
When lowering the S degree, improving processability, and achieving strict external dimensional accuracy, it is recommended to use polyfunctional monomers such as trimethylolpropane, trimethacrylate, tetramethylolmethane, and tetramethacrylate. preferable. As the main constituent rubber material, natural rubber, butadiene rubber, or a mixture thereof is selected in consideration of other physical properties required of the rubber roller, such as low abrasion, low heat generation, and low surface tack. 20 to 30 parts by weight of the above-mentioned reactive reinforcing filler is blended with 100 parts by weight of these rubbers. As a result, it is possible to lower the Move S degree of the unvulcanized rubber composition (45 or less), and therefore, the metal core is not distorted during vulcanization molding, and a rubber roller with uniform outer dimension accuracy can be produced. In addition, during vulcanization, the reinforcing filler undergoes a graft reaction with rubber molecules to achieve the high hardness (JIS hardness 70) required for the finished roller.
0 or more). The present invention will be explained below by showing examples. Example 1 A rubber cylindrical body 3 was integrally formed on a metal core body 2 using a rubber composition having the following composition to produce a rubber roller 1.

(See Figure 1) Butadiene BROl (manufactured by JSR) 10
0 parts by weight Zinc methacrylate 20 Dicumyl peroxide 0.5 Parts by weight (MLl)
Vulcanization conditions: 160° C. for 20 minutes The hardness (JIS) of the completed rubber roller 1 was 70, and the external dimensional accuracy was 0.02 mm.

Further, as a result of a test according to the adhesion test method for metal and vulcanized rubber stipulated in JIS63Ol-8, a phenomenon of rubber breakage occurred, indicating that it was strongly adhered to the metal. Example
2 A rubber roller having the same structure as in Example 1 was made using the following formulation in which natural comb was used instead of butadiene comb.

Natural rubber 100 parts by weight Zinc methacrylate 20 Dicumyl peroxide
1.0//Move S degree (MLl+41000C)
43 Vulcanization conditions: 160° C. x 2 O minutes The hardness of the rubber roller in this example was 70 mm.

Furthermore, as in the case of Example 1, the aforementioned adhesion test showed that the rubber broke. Example 3 In this example, a rubber roller was made using the following formulation, which was similar to Example 1 except that the amount of reactive reinforcing filler was increased.

Butadiene BROl (manufactured by JSR) 100 parts by weight Zinc methacrylate 30 Dicumyl peroxide 1,0 Mo[S degree (MLl+41000C)
) 45 Vulcanization conditions: 160°C x 20 minutes The hardness (JIS) of the rubber roller in this example is 900, and the external dimensional accuracy is 0.
02 mm, which is much smaller than the allowable external dimensional accuracy, and the adhesion to the metal core is also extremely strong.

Example 4 A rubber roller was made using the following compound.

This example uses trimethylolpropane, trimethacrylate (TMPT) as the reactive reinforcing filler.
Different from the example. Butadiene BROl (manufactured by JSR) 100
Weight part TMPT2O dicumyl peroxide
0.5 Move S degree (ML, +41000C) 35
Vulcanization conditions: 160°C x 20 minutes The hardness of the rubber roller in this example is 7
3 As is clear from the table, the Mooney viscosity is even lower than that of the rubber compositions of the previous three examples, and the external dimensional accuracy of the finished roller is also 0.01.
mm, more uniformity is obtained.

As detailed above, the present invention has less deviation in external dimensions,
To provide a rubber roller with required hardness and excellent wear resistance.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view and a cross-sectional view showing an example of the roller of the present invention. 1: Rubber roller, 2: Metal core, 3: Comb cylindrical body.

Claims (1)

[Claims] 1. About 20 to 30 parts by weight of a reactive reinforcing filler is mixed on a metal core with respect to 100 parts by weight of natural rubber or butadiene rubber or a mixture thereof, and the mixture is made of unvulcanized rubber. A rubber roller comprising an integrally formed rubber cylindrical body made of a rubber composition having a Mooney viscosity of 45 or less. 2. The rubber roller according to claim 1, wherein the reactive reinforcing filler is zinc methacrylate. 3. The rubber roller according to claim 1, wherein the reactive reinforcing filler is a polyfunctional monomer.