JPH10252743A - Rubber roller - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To combine the high abrasion resistance of urethane rubber and the high releasability (high non-adhesiveness) of silicone rubber, and to reduce the friction coefficient due to the change with time. Provide rubber roller. SOLUTION: The rubber roller of the present invention is composed of a foamed blend rubber containing urethane rubber and silicone rubber as main components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber roller for transporting a medium used in industrial machines, especially OA equipment.

[0002]

2. Description of the Related Art A rubber roller is mounted inside an industrial machine, and is widely used as a part for conveying paper and cloth. Printers used in rotary presses and word processors,
Rubber rollers of various shapes and materials are used in copiers, automatic teller machines (ATMs) installed in banks and post offices, and the like.

[0003] The required characteristics of the rubber transfer rollers used in these machines can be summarized in the following three points. 1) Satisfy the initial required characteristics. 2) Even if the device is used for a long time, the device cannot be used due to a change in the characteristics of the rubber roller (long life of the rubber roller). 3) Inexpensive molding into the used shape (low cost of the rubber roller).

Among the main required characteristics, the following factors can be cited as factors that affect the longevity of the rubber roller in 2). B) Due to external factors (environmental factors) such as operating temperature, humidity, ozone, etc., the rubber becomes viscous, dries or cracks, and the rubber material deteriorates with time. B) Due to the mechanical pressure on the rubber roller, the outer diameter of the rubber roller changes with use (the compression set characteristic is involved). C) The rubber is worn by contact friction with a transport medium (paper, ribbon, bill, etc.), and the outer diameter changes. D) Ink printed on the transport medium, oil attached to the transport medium, or the like adheres to the surface of the rubber roller as the transport medium is transported, thereby deteriorating the material of the rubber roller. E) Ink or oil adhering to the surface of the rubber roller lowers the friction coefficient of the rubber roller, causing a slip phenomenon with the medium, preventing normal conveyance. F) In addition, it has rubber elasticity even at a low temperature of about −10 ° C. as at room temperature.

On the other hand, the low cost of the rubber roller is dealt with by using an inexpensive raw material or devising the shape of the rubber roller to simplify the molding process.

[0006] Now, in the current commercially available apparatus, the above-mentioned a)
There is no satisfactory rubber roller that can cope with the factors (1) to (4), and when the transport performance is deteriorated, it is usual to replace the rubber roller with a new rubber roller. However, if the transport performance deteriorates early, the frequency of replacement is increased, and the user of the apparatus desires to extend the life of the transport performance. Further, in the case of a rubber roller mounted on a part where replacement work is difficult, it is desired that deterioration of the rubber roller does not determine the life of the apparatus.

As a technique for satisfying such a demand, a technique described in Japanese Patent Application Laid-Open No. 7-243436 has already been proposed. According to this, use of a blend rubber of urethane rubber and silicone rubber is mentioned as a material of the rubber. The technique described in this publication satisfies the above requirement by combining the high abrasion resistance of urethane rubber and the high mold release property (that is, high non-adhesion) of silicone rubber.

[0008] However, this technique may be inappropriately applied to a conveying device that requires a high friction coefficient for the rubber roller. That is, in order to achieve a high coefficient of friction, the rubber hardness must be low, but urethane rubber with low rubber hardness is susceptible to hydrolysis and degradation when exposed to high temperature and humidity conditions, Low wear. If the mixing ratio of silicone rubber is increased to cope with this, deterioration under high temperature and humidity conditions is unlikely to occur, but abrasion resistance remains low. Furthermore, it has been found that in a roller using a blend rubber of urethane rubber and silicone rubber, the coefficient of friction tends to decrease over time.

[0009]

The present invention combines the high abrasion resistance of urethane rubber and the high releasability (high non-adhesiveness) of silicone rubber, and at the same time, reduces the friction coefficient due to changes over time. An object of the present invention is to provide a rubber roller having low durability.

[0010]

The rubber roller according to the present invention comprises:
It is characterized by being composed of a foamed blend rubber containing urethane rubber and silicone rubber as main components.

According to the present invention, a roller obtained from a rubber obtained by simply blending these rubber components while maintaining the high abrasion resistance of the urethane rubber and the high release property (high non-adhesion) of the silicone rubber. It is possible to realize a rubber roller having a higher friction coefficient and less decrease in the friction coefficient due to aging. Hereinafter, the present invention will be described in detail.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The urethane rubber that can be used in the present invention can be appropriately selected from all kinds of known urethane rubbers such as ester-based urethane rubber, ether-based urethane rubber, and polycarbonate-based urethane rubber. The production method is not particularly limited either. For example, it may be synthesized starting from an appropriate monomer component (isocyanate component, polyol component, etc.), or may be produced using a so-called prepolymer method.

As an example, the urethane rubber obtained by the prepolymer method will be described. The molecular weight is 500 to 100 having isocyanate groups (-NCO) at both ends of the molecule.
A crosslinked urethane rubber obtained by using a liquid linear prepolymer of about 00 as a starting material and curing it with a monomer having a diamine group or a diol group can be used as the urethane rubber in the present invention. As the type of the prepolymer, any type of liquid urethane rubber prepolymer such as an ester urethane, an ether urethane, and a polycarbonate urethane may be used. Representative examples of the liquid urethane prepolymer include a prepolymer obtained by polycondensation of a polyol and a diisocyanate and having an isocyanate group at a molecular terminal. Urethane rubber prepolymers using ether diols as polyols are more preferred. Here, "liquid" means a urethane rubber prepolymer having a viscosity of 1500 poise or less at 100 ° C. As a curing agent for the urethane rubber prepolymer,
Compounds having active hydrogen can be used. Specific examples of the curing agent include diphenylamine, triisopropanolamine, and ethylene glycol.

Next, the silicone rubber which can be used in the present invention can be appropriately selected from all kinds of known silicone rubbers. The production method is not particularly limited either, and may be synthesized from a suitable starting monomer, for example, dimethyldichlorosilane, or may be produced using a prepolymer, for example, polydimethylsiloxane.

As an example, a silicone rubber produced by a prepolymer method will be described here. Basically, a molecular weight of 500 having a siloxane unit represented by the general formula-((R ₁ R ₂ ) SiO) _n- Starting from a liquid linear prepolymer of about 10,000 to about 10,000, a predetermined silicone rubber can be obtained. R ₁ and R ₂ in this general formula
Is an alkyl group having 1 to 5 carbon atoms (eg, a methyl group,
Ethyl group), an alkenyl group having 2 to 5 carbon atoms (eg, a vinyl group), and a phenyl group. Further, the silicone rubber prepolymer can be equally used whether it is an addition type or a condensation type such as an alcohol type or an oxime type in the classification regarding the curing reaction. The term “liquid” as used herein means that the viscosity of the prepolymer at 100 ° C. is 3 unlike the urethane rubber prepolymer.
It refers to a silicone rubber prepolymer of 000 poise or less. Also, the silicone rubber prepolymer can be used equally whether the cured form is one-part or two-part.

The mixing ratio of urethane rubber and silicone rubber is determined by the required characteristics (mainly,
Friction coefficient, abrasion resistance), and there is no particular limitation on the mixing ratio, but in order to express both the high abrasion resistance of urethane rubber and the high non-adhesion of silicone rubber, It is preferable that the mixing ratio of the urethane rubber and the silicone rubber is from 0.2: 0.8 to 0.8: 0.2.

In order to produce a foamed blend rubber comprising urethane rubber and silicone rubber, a so-called foaming agent is used. As the foaming agent in the present invention, for example,
Water, methylene chloride, chlorofluorocarbon, 2,2'-azobis (isobutyronitrile), azodicarbonamide, cyanoacetic acid, 4,4'-oxybis (benzenesulfonyl hydrazide), sodium hydrogen carbonate and the like can be used.

The rubber constituting the roller of the present invention may be mixed with one or more additional components such as an inorganic filler, a plasticizer, and an antioxidant generally added to rubber products. .

Examples of the inorganic filler include carbon fine particles, glass fine particles, silica fine powder, glass hollow particles, silicon carbide powder, silicon nitride powder, and white carbon. Particularly preferred as the inorganic filler is silicon carbide powder. Regardless of which filler is used, the average particle size of the filler is preferably 50 μm or less. 50 μm
The filler having a particle size exceeding the above range tends to be inconvenient for rubber roller molding. When an inorganic filler is used, its content is preferably 10 to 50% by weight of the total weight of the urethane rubber and the silicone rubber. 10% by weight
If the amount is less, the effect (reinforcing effect) due to the addition of the filler cannot be expected. On the other hand, if it exceeds 50% by weight, there are disadvantages such as an increase in rubber hardness and a decrease in friction coefficient.

Examples of the plasticizer include all oily low molecular weight components. The effect of the plasticizer is to lower the rubber hardness without lowering the abrasion resistance of the rubber and to increase the coefficient of friction, and to prevent the ink and the like adhering to the transport medium from adhering to the rubber surface ( (Release properties). Among the plasticizers, preferred are oily compounds often used as plasticizers for vinyl chloride, such as hydrocarbon oils, di-2-ethylhexyl phthalate, and dibutyl phthalate, and silicone oils. The plasticizer is preferably used in a range of 3 to 20% by weight of the total weight of the urethane rubber and the silicone rubber. If the amount is less than 3% by weight, the effect of adding the plasticizer is not exhibited.

Next, a method for producing the rubber roller of the present invention using the urethane-silicone foamed rubber will be described with reference to a case where a prepolymer is used as a rubber component. First, a predetermined amount of a urethane rubber prepolymer and a silicone rubber prepolymer are weighed and mixed. Further, a curing agent for urethane rubber, and in the case of two-part silicone rubber, a curing agent for silicone rubber (for example, a mixture of trimethoxysilane and an organotin compound, or a polysiloxane having a Si-H bond and a platinum compound) And a foaming agent. Since the foaming agent changes into a gas by heating from the outside or foams by releasing a gas component, the mixing process with the rubber prepolymer and the defoaming process are performed at room temperature as much as possible. Further, if necessary, other additives such as an inorganic filler and a plasticizer are added.

After all the components have been mixed, a defoaming operation is performed, and the rubber components are poured into a predetermined mold so as to be formed into a rubber roller, followed by casting. After casting, foaming is performed at a temperature suitable for foaming the used foaming agent.
Curing is performed for a predetermined time at a temperature up to about ° C to obtain a rubber roller having a predetermined shape.

[0023]

Next, the present invention will be further described with reference to the following examples. Of course, the invention is not limited to these examples.

Example 1 In this example, a cylindrical foam blend rubber roller having an outer diameter of 30 mm, an inner diameter of 20 mm, and a thickness of 7 mm was manufactured using the following components.

Urethane rubber 100 parts by weight (Sanprene P-664 manufactured by Sanyo Chemical Industries) Urethane rubber curing agent 5.9 parts by weight (triisopropanolamine) Silicone rubber 70 parts by weight (TSE-3450A manufactured by Toshiba Silicone Co., Ltd.) Silicone rubber curing agent 7.0 parts by weight (TSE-3450B manufactured by Toshiba Silicone Co., Ltd.) Blowing agent 2.5 parts by weight (2,2'-azobis (isobutyronitrile))

These components were mixed and stirred at 45 ° C. to remove bubbles. The obtained mixture was cast into a mold, and after defoaming, the mold was charged into a constant temperature bath at 80 ° C. for 60 minutes to foam. Thereafter, a curing reaction was performed at 100 ° C. for 10 hours. The obtained rubber roller was measured for A-type rubber hardness specified in JIS K 6301.
5 degrees.

Example 2 A foam-blended rubber roller was manufactured in the same manner as in Example 1 except that the following components were used.

Urethane rubber 70 parts by weight (Sanpreka P-664 manufactured by Sanyo Chemical Industries) Urethane rubber curing agent 4.1 parts by weight (triisopropanolamine) Silicone rubber 100 parts by weight (TSE-3450A manufactured by Toshiba Silicone Co., Ltd.) Silicone rubber curing agent 10 parts by weight (TSE-3450B manufactured by Toshiba Silicone Co., Ltd.) Blowing agent 2.5 parts by weight (2,2'-azobis (isobutyronitrile))

JIS K measured in the same manner as in Example 1.
The A-type rubber hardness according to 6301 was 40 degrees.

Example 3 Using the following components, a foam-blended rubber roller having the same dimensions as those produced in Example 1 was produced.

Urethane rubber 100 parts by weight (Takeda Pharmaceutical Co., Ltd. Takenate XC-15E-800) Urethane rubber curing agent 7.1 parts by weight (3,3'-dichloro-4,4'-diaminodiphenylmethane) Silicone rubber 70 parts by weight Part (TSE-3508A manufactured by Toshiba Silicone Co., Ltd.) 7.0 parts by weight of silicone rubber curing agent (TSE-3508B manufactured by Toshiba Silicone Co., Ltd.) Blowing agent 1.2 parts by weight (azodicarbonamide) Silicon carbide filler 50 parts by weight (Shinano (SFP-1.7 manufactured by Denki Smelting Co., average particle size 1.7 μm)

These components were mixed and stirred at 120 ° C., defoamed, and cast into a mold. Subsequently, the foam was defoamed, and the mold was placed in a thermostat at 180 ° C. for 20 minutes to foam. Next, the rubber was cured at 120 ° C. for 12 hours to obtain a rubber roller molded product. This molded product was a uniformly foamed rubber, and had an A-type rubber hardness of 48 degrees as measured by JIS K6301.

Example 4 A foam-blended rubber roller was manufactured in the same manner as in Example 3 except that the following components were used.

Urethane rubber 100 parts by weight (Takenate XC-15E-800 manufactured by Takeda Pharmaceutical Co., Ltd.) Urethane rubber curing agent 7.1 parts by weight (3,3'-dichloro-4,4'-diaminodiphenylmethane) Silicone rubber 70 parts by weight Part (TSE-3508A, manufactured by Toshiba Silicone Co., Ltd.) 7.0 parts by weight of silicone rubber curing agent (TSE-3508B, manufactured by Toshiba Silicone Co., Ltd.) 3.0 parts by weight of foaming agent (water) 40 parts by weight of silicon carbide filler (Shinano Electric Refining Co., Ltd.) 2.3 parts by weight of silicone-based oil (Paintad # 54 manufactured by Dow Corning Asia)

JIS K630 of the obtained rubber roller
The A-type rubber hardness according to No. 1 was 48 degrees.

Comparative Example 1 A rubber roller was manufactured in the same manner as in Example 1 using the following components. The A-type rubber hardness of the obtained roller was 60 degrees.

100 parts by weight of urethane rubber (Samprene P-664, manufactured by Sanyo Chemical Industries) 5.9 parts by weight of urethane rubber (triisopropanolamine) 70 parts by weight of silicone rubber (TSE-3450A, manufactured by Toshiba Silicone Co., Ltd.) Silicone rubber curing agent 7.0 parts by weight (TSE-3450B manufactured by Toshiba Silicone Co., Ltd.)

Comparative Example 2 A rubber roller was manufactured in the same manner as in Example 1 using the following components. The A-type rubber hardness of the obtained roller was 64 degrees.

Urethane rubber 100 parts by weight (Samprene P-664 manufactured by Sanyo Chemical Industries) Urethane rubber curing agent 5.9 parts by weight (triisopropanolamine)

Comparative Example 3 A rubber roller was manufactured in the same manner as in Example 1 using the following components. The A-type rubber hardness of the obtained roller was 45 degrees.

100 parts by weight of silicone rubber (TSE-3450A manufactured by Toshiba Silicone) 10 parts by weight of silicone rubber curing agent (TSE-3450B manufactured by Toshiba Silicone)

For each of the rubber rollers obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the friction coefficient was measured, and the abrasion resistance was evaluated by measuring the weight loss.

The measurement of the coefficient of friction was performed using the apparatus shown in FIG. In this measuring device, a suitable paper 2 (for example, bills) is placed on a moving table 1, and a rubber roller 3 fixed so as not to rotate on the upper surface thereof is brought into contact with the rubber roller 3. In addition, the friction coefficient of the roller when the moving table 1 is moved rightward in the figure is measured. The friction coefficient μ is obtained by calculation as μ = F / W by measuring the frictional force F with a load cell 6 that detects a load in the horizontal direction via the rod 5. Reference numeral 7 in the figure denotes a balance weight.

The weight reduction of the rubber roller for evaluating the abrasion resistance was carried out by an apparatus schematically shown in FIG. This apparatus includes a pick roller (test rubber roller) 11 to be evaluated and a feed roller 12, each of which is independently driven by a stepping motor (not shown). As the transport medium 13, an endless tape made of plain paper whose entire surface was blackened using a copying machine was used. Pickup roller 1 to be evaluated
1, a desired load can be applied by the pressure setting balancer 15 via the roller 14, and the same pressure as the mechanical pressure applied to the rubber roller by the actual machine in use can be applied to the pickup roller 11. (The details of this measuring device are described in JP-A-7-243436.) The weight loss of the test rubber roller after operating the device for 10 hours was measured to evaluate the abrasion resistance. The coefficient of friction (the coefficient of friction after 10 hours) was measured by the apparatus shown in FIG. The initial coefficient of friction in Table 1 corresponds to the coefficient of friction determined for the rubber roller before the weight loss measurement by the apparatus in FIG.

The friction coefficient and abrasion resistance of each of the above examples obtained by these measurements are shown in Table 1 as relative values.

[0046]

[Table 1]

[0047]

As described above, according to the present invention,
Without losing wear resistance, it is possible to effectively suppress a decrease in friction coefficient due to a change with time. Therefore, the rubber roller of the present invention is extremely effective as a component for repeatedly transporting paper or cloth, and is used as a media transport rubber roller for printers and copiers used in rotary presses and word processors, as well as for automatic cash depositing and depositing. It can be widely used as a rubber roller for transporting a medium of a machine such as a payment device (ATM) that requires particularly high reliability.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an apparatus used for measuring a coefficient of friction.

FIG. 2 is a diagram illustrating an apparatus used for measuring a weight loss amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Moving table 2 ... Paper 3 ... Rubber roller 4 ... Weight 6 ... Load cell 11 ... Test rubber roll 12 ... Feed roll 13 ... Conveying medium 15 ... Pressure setting balancer

Claims (8)

[Claims] 1. A rubber roller comprising a foamed blend rubber containing urethane rubber and silicone rubber as main components. 2. The urethane rubber is a prepolymer obtained from the polycondensation of a polyol and a diisocyanate, and is obtained from a urethane rubber prepolymer having an isocyanate group at a molecular terminal. Rubber roller. 3. The urethane rubber prepolymer is obtained using an ether-based diol.
Rubber roller as described. 4. The urethane rubber prepolymer of 100
The viscosity at ℃ is 1500 poise or less.
Or the rubber roller according to 3. 5. The rubber roller according to claim 1, wherein the silicone rubber is obtained from a silicone rubber prepolymer having a viscosity at 100 ° C. of not more than 3000 poise. 6. The rubber roller according to claim 1, wherein the foamed blend rubber further includes at least one of an inorganic filler and a plasticizer. 7. The rubber roller according to claim 6, wherein the inorganic filler is silicon carbide having an average particle size of 50 μm or less. 8. The plasticizer is a silicone oil,
The rubber roller according to claim 6.