JPS5925885B2 - rubber roller - Google Patents

Description

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

Conventionally, this type of roller has a metal core 7 coated with natural rubber, butadiene rubber, chloroprene rubber, or
It is made by integrally forming a rubber cylindrical body 3' made of synthetic rubber such as urethane rubber, silicone rubber, or fluorine rubber, but as shown in Table 1, these rubbers have one characteristic in terms of required performance. Just as it has been said that if one performance is good, another performance is bad, so there is no one that satisfies all performances. In addition, since this type of roller is required to have considerable hardness (JIS hardness 700 or higher) for its purpose, a considerable amount (usually 50 parts by weight or more) of carbon black, silica, and calcium carbonate are added to the above-mentioned rubber. It is made by blending inorganic reinforcing fillers such as As a result, the Mooney viscosity of the unvulcanized rubber becomes extremely high, causing distortion of the metal core due to the rubber pressure during rubber roller molding, and as the core returns to its straight state after molding, the outer rubber roller portion It becomes distorted. Although this deformation is not so noticeable in appearance, since the external dimensional accuracy allowed for this type of rubber roller is within 0.05 mm, the outer circumferential surface is subjected to parallax processing after vulcanization is completed. must be carried out. Furthermore, strong adhesion between the metal core body 2' and the rubber cylindrical body 3' is also a necessary requirement.

The object of the present invention is to eliminate the above-mentioned drawbacks at once and provide a rubber roller that can satisfy all the required performances at the same time. Forming a thin surface layer (hereinafter tentatively referred to as "urethane rubber coating layer") formed by applying urethane rubber on the surface of a rubber cylinder, and coating the rubber cylinder with a conventional inorganic reinforcing filler. Instead of this, a reactive reinforcing filler is blended to make the unvulcanized rubber have a low Mooney viscosity.

As can be seen from Table 1, the rubber material that is the main constituent material of the roller of the present invention is a natural rubber material that is superior on average to other rubber materials in terms of required performance, especially abrasion resistance, heat generation property, and surface tackiness. Use rubber and butadiene rubber selectively.

One of the features of the present invention is that a small amount of reactive reinforcing filler is blended into these rubbers in order to achieve uniform external dimensional accuracy in the finished roller, and this point will be explained in detail later. Other characteristics of the present invention are the above-mentioned properties of natural rubber and butadiene rubber, especially the aging resistance which is particularly poor compared to other rubber materials as shown in Table 1, and the aging resistance which is comparatively slightly poor. In order to compensate for surface tackiness, a surface layer 5 coated with urethane rubber is formed on the surface of the rubber cylindrical body 3 made of the rubber.

(See Figure 2) If the thickness of this urethane coating layer 5 is too thick, it will increase the internal heat storage in the rubber cylindrical body 3, and the allowable external dimensional accuracy of this type of roller is 0.05.
The thickness of the roller is 0.05 mm or less, taking into consideration that a roller that is worn out beyond that range will no longer be usable. Making it thicker than this is not only economically wasteful, but it cannot be formed by a simple method such as brush coating, so it is necessary to wrap it around the cylindrical body 3 in the form of a rubber sheet and press it. It must be done by a laborious method such as sulfur molding. When forming the urethane rubber coating layer 5 on the rubber cylindrical body 3, the surface of the cylindrical body 3 is previously treated with chlorine water to form the halogenated layer 4 in order to ensure strong adhesion between both layers. is preferred.

Examples of reactive reinforcing fillers that are blended into the rubber composition constituting the rubber cylindrical body 3 include zinc methacrylate,
Examples include polyfunctional monomers such as trimethylolpropane, trimethacrylate, tetramethylolmethane, and tetramethacrylate. Since these compounds do not react in the uncured, underground state, they graft react with the rubber molecules of unvulcanized rubber, increasing the hardness of the finished roller to the required value (JIS hardness 700) despite the addition of a small amount. above).

The reinforcing filler is preferably added in an amount of about 20 to 30 parts by weight per 100 parts by weight of rubber, thereby increasing the viscosity of the unvulcanized rubber composition (MLl+4100'C).
can be set to 45 or less, and therefore, it is possible to achieve uniform outer dimensional accuracy of the completed roller without causing distortion of the metal core 2 during vulcanization molding. Among the above-mentioned reactive reinforcing fillers, zinc methacrylate may be selected when strong adhesion between the metal core 2 and the rubber cylinder 3 is particularly important. In cases where importance is placed on lowering the processability and uniformity of strict external dimensional accuracy, it is preferable to use polyfunctional monomers such as trimethylolpropane and trimethacrylate.

As shown in Table 1, the rubber roller of the present invention has extremely superior wear resistance compared to conventional rollers, has extremely low temperature rise due to heat generated during use, and has almost no surface adhesion.
It satisfies all performance requirements, including excellent aging resistance.

Incidentally, while the abrasion resistance is improved by coating the surface with urethane, the urethane rubber coating layer, which is inherently inferior in terms of heat generation, is 0.05m7! In addition to being formed extremely thin, less than l,
Since the rubber material of the rubber cylindrical body 3 has a low heat generation property, by absorbing the heat of the urethane rubber coating layer 5, the entire body can have a low heat generation property as shown. Further, due to the properties unique to urethane rubber, surface tackiness is extremely low, and contact between atmospheric oxygen and the rubber of the internal cylindrical body is blocked to prevent accelerated aging of the rubber material. In addition, each evaluation score in the above table was determined based on the following test method and criteria.

Test method: A piece of test paper was held under pressure of 1 kg between the rubber roller of the present invention and a metal roller for testing installed parallel to the rubber roller, and then frictionally rotated at 1000 revolutions/minute for 100 hours. let

Note that the ambient atmosphere temperature is maintained at 30°C. Evaluation criteria: 1. Wear performance is determined by the amount of wear on the outer diameter of the rubber roller as follows.

0.01mm or less=excellent, 0.01~0.019=excellent,
0.02 to 0.04 Good, 0.04 or more = Bad 2 The heat generation performance is determined as follows based on the measured temperature of the rubber roller at the end of the test.

45°C or lower (2 small), 45 to 65°C (1 medium), 65°C or above (2 large) 3. Surface tack is rated as "high" if the test paper strips frequently adhere to the surface, and "small" if it does not occur at all. , and those in between are evaluated as "medium."

4. Aging resistance performance is determined as follows based on the amount of increase in hardness from the initial hardness when the temperature of the rubber roller drops to room temperature after the test.

±00 Excellent, +1 = Excellent, +2 First = Good, +30 - Poor Below, embodiments of the present invention will be shown and explained.

Example 1 1 A rubber cylindrical body 3 made of a rubber composition having the following composition is vulcanized and molded on a metal core body 2.

(See Figure 2) Butadiene BROl (manufactured by JSR) 10
0 parts by weight Zinc methacrylate 20 Dicumyl peroxide 0.5 Parts by weight Viscosity MLl
+4 (1000C) 43 Vulcanization conditions: 16
0°C x 20 minutes 2 The surface of the rubber cylinder 3 was sandblasted, and then heated at 25°C with chlorine water with a chlorine concentration of 0.5%.
Impregnation treatment is carried out for 20 minutes at room temperature.

3. On the surface-treated rubber cylindrical body 3, a solution of a millable urethane rubber compound is applied with a brush to a thickness of 0.05 mm to form a urethane coating layer 5.

4.Finally, the coating layer 5 is heated and vulcanized.

Hardness of the rubber roller completed in this example (JIS hardness)
The diameter was 70, and the external dimension accuracy was 0.02 mm. Moreover, as a result of the test using the aforementioned test method, the amount of wear was 0.
006mm1 calorific value is 40℃, aging (hardness change) is +
1 m, and no phenomenon of adhesion and wrapping of the test paper pieces was observed. Furthermore, the results of the adhesion test specified in JIS63Ol-8 also showed that the rubber part was broken and was strongly adhered to the metal.

Example 2 A rubber roller was manufactured in the same manner as in Example 1, except that the rubber cylindrical body 3 was made of a natural rubber composition having the following composition.

Natural rubber 100 parts by weight Zinc methacrylate 20 Dicumyl peroxide
1,0〃Move S degree (MLl+4100℃)
43 Vulcanization conditions: 160 lC x 20 minutes The hardness of the rubber roller in this example is 70 minutes, and the external dimension accuracy is 0.01 m7! 1, and as a result of the physical property test mentioned above, the wear amount was 0.006 mm, and the calorific value was 43°C.
, hardness change +1, no adhesion phenomenon of test paper pieces was observed, and the surface adhesion performance was extremely good.

Example 3 The rubber cylindrical body 3 is formed from a butadiene rubber composition with the following formulation, the halogenation treatment on the surface of the cylindrical body is performed twice by brush coating using an organic halide (Chemroc J-mo V01), and a two-liquid composition. This example differs from Example 1 in that a urethane coating layer is formed by heat curing using a solution of polyurethane comb.

Butadiene BROl (manufactured by JSR) 100 parts by weight Zinc methacrylate 30 Dicumyl peroxide 1.0 Move S degrees (MLl+4100 C
) 45 Vulcanization conditions: 160°C x 2O minutes The various performances of the rubber roller in this example are as follows.

Hardness (JIS) = 90, External dimension accuracy = 0.02mm1
Amount of wear = 0.005 mm1 Calorific value = 40°C, change in hardness - +150 Example 4 A rubber cylindrical body was made from the following compound using trimethylolpropane and trimethacrylate (TMPT) as reactive reinforcing fillers. A rubber roller was manufactured in the same manner as in Example 1 except for the following.

Butadiene BROl (manufactured by JSR) 100 parts by weight TMP
T2O〃Dicumyl peroxide 0.5〃mu
[Viscosity (MLl+4100℃) 35 Vulcanization conditions: 16
The various performances of the rubber roller in this example at 0°C x 2O are as follows.

Hardness (JIS) = 73, external dimension accuracy -0.01mm.
Amount of wear = 0.006mM1 Calorific value = 40℃, hardness change 1 + 1, surface adhesion excellent.

Example 5 A rubber roller was manufactured in the same manner as in Example 4 except that natural rubber was used instead of butadiene rubber in the rubber cylinder composition.

Natural rubber 100 parts by weight TMPT2
O〃Dicumyl peroxide 1.0〃Mu[Me
[Viscosity (MLl+41000C) 35 Vulcanization conditions: 1
60°C x 20 minutes The various performances of the rubber roller in this example are as follows.

Hardness (JIS) = 73, External dimension accuracy = 0.01mT1
11 Amount of wear 2 0.006 UW 1 Calorific value = 42℃, Hardness change - +16, Excellent surface tackiness.

As detailed above, the present invention satisfies all required performances such as abrasion resistance, heat generation property, surface tackiness, and aging resistance.
To provide a rubber roller with uniform external dimensions and firmly bonded to an internal metal core.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional roller, and FIG. 2 is a cross-sectional view and a longitudinal cross-sectional view of an example of the roller of the present invention. 1, 1': Rubber roller, 2, 2': Metal core, 3, 3'
: Rubber cylindrical body, 4: Halogenated layer, 5: Urethane rubber coating layer.

Claims (1)

[Scope of Claims] 1. From an unvulcanized rubber composition with a low Mooney viscosity containing about 20 to 30 parts by weight of a reactive reinforcing filler per 100 parts by weight of natural rubber, butadiene rubber, or a mixture thereof. A rubber roller with a formed metal core,
This roller is a rubber roller characterized by having a thin urethane rubber adhesion layer on its surface. 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. 4. The rubber roller according to any one of claims 1 to 3, wherein a halogenated layer is formed on the surface of the rubber cylinder prior to forming the urethane rubber coating layer.