JP2001310421A - Elastic rubber coated composite - Google Patents

Abstract

(57) [Summary] PROBLEM TO BE SOLVED: It can be suitably used as a cushion material, a packing material, a spacer for electric / electronic parts, etc., and particularly as a separator of a fuel cell. An elastic rubber-coated composite is provided. A discharge nozzle is provided near at least one surface of a non-stretchable thin plate, and a liquid rubber is discharged from the discharge nozzle while relatively moving the non-stretchable thin plate and the discharge nozzle, and then cured to form an elastic rubber having a specific shape. An elastic rubber-coated composite formed by forming a layer, wherein the liquid rubber is a mixture of a liquid silicone resin and a liquid fluororesin, and has a viscosity at 25 ° C. (based on JIS K-6381) of 70 to 300 Pa.
-An elastic rubber-coated composite, which is in the range of S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be suitably used as a cushion material, a packing material, a spacer for electric and electronic parts and the like, particularly as a separator of a fuel cell, the product is easy to handle, the production efficiency is excellent, and the durability is particularly high. The present invention relates to an elastic rubber-coated composite having excellent properties.

[0002]

2. Description of the Related Art Conventionally, elastic rubbers such as silicone rubber and fluoro rubber have excellent properties such as heat resistance, electrical insulation and chemical resistance. Used for applications. When a thin film made of the above elastic rubber and having a relatively thin thickness is to be incorporated into electric / electronic parts as it is, wrinkles may occur on the thin film, or the thin films may adhere to each other and become difficult to peel off. There was a problem with sex. Therefore, in order to solve such a problem, there has been known a laminate in which a single elastic rubber and a non-stretchable thin plate such as a metal thin plate are combined and integrated.

[0003] As a method of the above-mentioned composite integration, a method of placing an elastic rubber sheet on at least one side of a thin plate and heating and pressurizing is usually performed.
If the alignment is difficult or if the thin plate has irregularities on the surface, there is a problem that it is difficult to bond the thin plate uniformly.

Therefore, a laminate in which an elastic rubber layer is formed by an injection molding method has been proposed. Although this method can improve the production efficiency to some extent, it has a problem that non-stretchable thin plates other than metal plates are liable to be broken, and burrs are generated in gaps such as a mating surface of a mold and it is difficult to form an accurate elastic rubber layer. there were.

Therefore, a discharge nozzle is provided in the vicinity of at least one surface of a metal or carbon thin plate, and liquid rubber is discharged from the discharge nozzle while relatively moving the thin plate and the discharge nozzle, and then cured to form an elastic rubber layer having a specific shape. Have been proposed. This method has an advantage that a rubber layer having a complicated shape can be easily formed without generation of burrs or the like. However, since the viscosity is low depending on the liquid rubber used, it flows after discharge and the thickness cannot be maintained. In addition, there is a problem that the versatility is likely to be inferior due to relatively high material costs.

[0006]

DISCLOSURE OF THE INVENTION The present invention has found an elastic rubber-coated composite which can solve the above-mentioned problems. The gist of the present invention is to provide a composite which is close to at least one surface of a non-stretchable thin plate. An elastic rubber-coated composite formed by providing a discharge nozzle, discharging liquid rubber from the discharge nozzle while relatively moving the non-stretchable thin plate and the discharge nozzle, and then curing to form an elastic rubber layer of a specific shape, The liquid rubber is a mixture of a liquid silicone resin and a liquid fluororesin, and has a viscosity at 25 ° C. (according to JIS K-6381) of 7
An elastic rubber-coated composite having a range of 0 to 300 Pa · S.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The non-stretchable thin plate used in the present invention may be a hard base material capable of holding a rubber layer to be coated, and in particular, a fuel cell separator having a specific resistance of 1 × 10 ⁻¹ Ωcm or less. A thin plate is preferably used. As such a conductive thin plate, a metal thin plate such as a steel plate, a stainless steel plate, a plated steel plate, an aluminum plate, or the like, or a carbon thin plate made of resin-impregnated graphite or the like can be used, but is not limited thereto. The thickness of the non-stretchable thin plate is preferably in the range of 0.1 to 3.0 mm, and those having irregularities on the surface can also be used. Although the shape of the unevenness varies depending on the use or the like, the unevenness has a three-dimensional structure. In a case where the use is a fuel cell, particularly a separator of a polymer electrolyte fuel cell, the groove corresponds to a fuel gas flow channel groove.

In the present invention, a discharge nozzle is provided near at least one surface of the non-stretchable thin plate, and a liquid rubber of a specific composition is discharged while relatively moving the non-stretchable thin plate and the discharge nozzle to form an elastic rubber layer. In particular, the moving speed is 5 to 100 mm / sec, and the discharge pressure is 50 to 100 mm / sec.
What is necessary is just to determine and shape | mold suitably in the range of 1,000 kPa.

The liquid rubber used in the present invention is a polymer that flows at room temperature, has a three-dimensional network structure by an appropriate chemical reaction, and has the same physical properties as ordinary crosslinked rubber. The liquid rubber is a mixture of a liquid silicone resin and a liquid fluororesin, and has a viscosity at 25 ° C. (JISK
(According to −6681) in the range of 70 to 300 Pa · S. Liquid silicone resin alone has the problem that it is difficult to maintain its thickness due to flow after discharge, and liquid fluorine resin has the problem of increased cost. An excellent rubber layer can be formed, and a low-cost elastic rubber-coated composite can be obtained. The viscosity after mixing is 7
If the pressure is less than 0 Pa · S, the thickness cannot be maintained due to the flow after the discharge, and 3
If it exceeds 00 Pa · S, there is a problem that the fluidity after discharge is insufficient and the area of adhesion to the thin plate is reduced. The viscosity may be measured by a single cylinder rotary viscometer according to JIS K-6381.

Here, the composition of the liquid silicone resin used for the liquid rubber is an addition type silicone obtained by subjecting the following liquid A and liquid B to a cross-linking reaction, and contains 30 to 90% by weight of a vinyl group-containing silicone resin. Liquid silicone resins can be suitably used.

[0011]

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The silicone resin may appropriately contain a silicone resin as a reinforcing agent. Further, as the composition of the liquid fluororesin used in the liquid rubber, a liquid C resin having the following skeletal structure can be suitably used.

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The mixing ratio of the liquid silicone resin and the liquid fluororesin is preferably in the range of 3/7 to 9/1. If the mixing ratio is less than 3/7, the fluidity after discharge is insufficient, and the mixing ratio with the thin plate is low. If the adhesive area is apt to decrease, and if it exceeds 9/1, it is difficult to maintain the thickness due to flow after ejection.

The surface of the above-mentioned non-stretchable thin plate has
It is preferable to provide various primer layers from the viewpoint of adhesion. This primer layer may be coated by a usual method such as a spray method or a dipping method. The thickness of the primer layer is preferably in the range of 0.01 μm to 5.0 μm. If the thickness is less than 0.01 μm, it is difficult to adjust the coating thickness. Few. The thickness of the elastic rubber layer after discharge molding is 0.05 m
m to 4.0 mm, preferably 0.05 to 4.0 mm.
When the thickness is less than 0.08 mm, the elasticity effect is hardly obtained, and the use as a packing material is poor. When the thickness exceeds 4.0 mm, it is difficult to reduce the size of a combustion battery, particularly for a separator of a polymer electrolyte fuel cell, and the cost is high. Easy to be.

Further, the hardness of the elastic rubber layer after the discharge molding is preferably in the range of 20 to 70, preferably 30 to 60. The hardness is measured according to JIS K6301 spring type hardness test A type. If the hardness is less than 20, the rubber repulsion force is low, and the initial sealing force as a packing material is insufficient, resulting in poor sealing. If the hardness is more than 70, the rubber tends to be too hard and lack elasticity.

The elastic rubber-coated composite of the present invention can be used for cushioning materials, packing materials, spacers, O-rings and the like of electric / electronic parts, etc., and is particularly used for separators of fuel cells (polymer electrolyte fuel cells). It can be suitably used. Such separators are required to be more miniaturized, and have excellent accuracy because a large number of separators are used in an overlapping manner.
There is a demand for a separator having good productivity and particularly good durability, and the elastic rubber composite of the present invention can easily satisfy such a demand.

[0017]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. (Example 1) Specific resistance 1 × 10 ⁻⁵ Ω after primer treatment (“XP81-B0016” manufactured by Toshiba Silicon Corporation)
A liquid silicone resin containing silicone resin defoamed into a 50 cc syringe with a stainless steel plate (1.0 mm thick) placed on a movable stage (Shin-Etsu Chemical Co., Ltd.)
(KE1935, manufactured by Shin-Etsu Chemical Co., Ltd.) and 30% by weight of defoamed liquid fluororesin (SIFEL3510, manufactured by Shin-Etsu Chemical Co., Ltd.). Further, the mixed resin in the syringe was defoamed, and the mixed resin was discharged from a nozzle at the tip of the syringe using a three-axis robot, and moved in a specific shape in a linear manner, thereby applying the mixed resin onto a steel plate to form a rubber layer. Nozzle diameter 1.5
The coating was performed at a discharge pressure of 400 kPa using a needle-shaped nozzle having a diameter of 2 mm.

After the application, the substrate is placed in a drying oven and is heated at 160 ° C. × 2
The fuel cell was cured under the heating condition for one minute to obtain a fuel cell separator.
In the obtained fuel cell separator, the adhesion between the stainless steel plate and the rubber layer was good and there was no separation or the like, and the thickness of the rubber layer was 0.8 mm, and there was no problem in performance as a fuel cell separator. The viscosity of the mixed resin of the liquid silicone resin and the liquid fluororesin used was 150 Pa · s at 25 ° C., and the hardness of the rubber layer after curing was 50.

[0019]

The elastic rubber-coated composite of the present invention has the advantages that it can maintain elasticity for a long time, has excellent durability, and can be manufactured at low cost.・ Cushion materials and packing materials for electronic components, etc.
It is very useful as a spacer, particularly as a separator for a fuel cell (polymer electrolyte fuel cell).

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme coat II (reference) // H01M 8/10 H01M 8/10 F term (reference) 4F100 AB04 AK17B AK52B AL05B AN02B AR00A BA02 BA03 BA06 BA10B BA13 EH46B EJ05B GB41 JA06B JG01A JG04A JK06 JK08A JL00 YY00A YY00B 4J002 CH00Y CH05Y CP04X CP14W GD00 GG02 GJ02 5H026 AA06 CX08 EE18

Claims (5)

[Claims] 1. A discharge nozzle is provided in proximity to at least one surface of a non-stretchable thin plate, and liquid rubber is discharged from the discharge nozzle while relatively moving the non-stretchable thin plate and the discharge nozzle, and then cured to obtain a specific shape of elasticity. An elastic rubber-coated composite formed by forming a rubber layer, wherein the liquid rubber is a mixture of a liquid silicone resin and a liquid fluororesin, and has a viscosity at 25 ° C (based on JIS K-6381) of 70 to 300 Pa.
-An elastic rubber-coated composite, which is in the range of S. 2. A non-stretchable thin plate having a specific resistance of 1 × 10
The elastic rubber-coated composite according to claim 1, comprising a conductive thin plate having a resistivity of ^-1 Ωcm or less. 3. A liquid silicone resin having an addition type silicone as a main component obtained by subjecting a liquid rubber to a crosslinking reaction between the following liquid A and liquid B, and a liquid fluorine resin of liquid C having the following skeletal structure. The elastic rubber-coated composite according to claim 1, wherein Embedded image Embedded image Embedded image 4. The elastic rubber-coated composite according to claim 3, wherein the mixing ratio of the liquid silicone resin and the liquid fluororesin is in the range of 3/7 to 9/1. 5. The elastic rubber-coated composite according to claim 1, which is used for a separator of a fuel cell.