JP2000156215A - Silicone resin-coated metal composite and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide silicone resin-coated metal composite and manufacturing method thereof, suitably used as a cushioning material, a packing material, and a spacer for an electrical and electronic components, and particularly as a separator of a fuel cell (a slid polymer fuel cell), easy to handle as a product and excellent in high productivity. SOLUTION: This silicone resin-coated metal composite comprises a specified shaped silicone resin layer formed by discharging silicone resin on one surface of a metal thin plate from an injection nozzle, and a silicone resin thin film layer formed on an other surface of the metal thin plate by screen printing. In manufacturing the silicone resin-coated metal composite, the injection nozzle is provided on an adjacent of the one surface of the metal thin plate, a specified shaped silicone resin layer is formed by relatively moving the metal thin plate and the injection nozzle and discharging silicone resin from the injecting nozzle. On the other surface, the silicon resin thin film layer is formed by screen printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silicone resin which can be suitably used as a cushioning material, a packing material, a spacer for electric and electronic parts, and particularly as a fuel cell separator. In particular, the product is easy to handle and has excellent production efficiency. The present invention relates to a coated metal composite and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, silicone rubber has been used in various applications such as the above cushioning materials and spacers because of its excellent properties such as heat resistance and electrical insulation. If a relatively thin thin film made of the above silicone rubber alone is incorporated into electrical or electronic parts, etc. 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, a laminate in which a silicone rubber alone and a non-stretchable metal thin plate are combined and integrated is known (for example, JP-A-4-86256,
No. 2-470).

As a method of the composite integration, a method of placing a silicone rubber sheet on at least one surface of a thin metal plate and applying heat and pressure is usually performed. There is a problem that it is difficult to bond the thin metal sheet evenly if the metal sheet has irregularities on the surface.

Therefore, a metal composite in which a silicone resin layer is formed by an injection molding method has been proposed. Although this method can improve the production efficiency to some extent, it is difficult to form an accurate silicone resin due to the occurrence of burrs by injection molding, and in the case of a fuel cell separator, replace or remove defective parts from the obtained separator. There is a problem that things are difficult to do. In addition, in the injection molding method, since a silicone resin having adhesiveness cannot be used due to a problem of releasability from a mold, a process of imparting easy adhesion such as a primer treatment is required for bonding the metal sheet and the silicone resin. This hindered mass production.

In particular, as a separator for a fuel cell, a laminated body in which a silicone rubber simple substance as a packing material is integrally integrated on one surface of a non-stretchable thin metal plate is used, and is stacked with an electrolyte membrane, an electrode material and the like interposed therebetween. Use is made. In this case, the silicone rubber having a specific shape performs the gas sealing function, but in order to ensure the sealing performance, when stacked, it is necessary to completely adhere the silicone rubber layer to the opposite back surface of the metal sheet opposite to the surface. There has been a demand for a separator that can satisfy various requirements.

[0006]

SUMMARY OF THE INVENTION The present invention has found a silicone resin-coated metal composite and a method for producing the same which can solve the above-mentioned problems. A silicone resin-coated metal composite formed by discharging a silicone resin from a nozzle to form a silicone resin layer of a specific shape and forming a silicone resin thin film layer on the opposite surface of the metal thin plate by screen printing, and a metal thin plate. An injection nozzle is provided close to one side, and while the metal sheet and the injection nozzle are relatively moved, a silicone resin is discharged from the injection nozzle to form a silicone resin layer of a specific shape, and a silicone resin thin film layer is formed on the opposite side by screen printing. Forming a silicone resin-coated metal composite.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
As the metal thin plate used in the present invention, a steel plate, a stainless steel plate, a plated steel plate, an aluminum plate, a copper plate, a titanium plate and the like are suitable, but not limited thereto. The thickness of the thin metal plate is preferably in the range of 0.1 to 2.0 mm, and a metal plate 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 metal composite of the present invention, a silicone resin is discharged from an injection nozzle on one side of the metal sheet to form a silicone resin layer of a specific shape, and a silicone resin thin layer is formed on the other side. The formation method is such that an injection nozzle is provided in proximity to one surface of a thin metal sheet, a silicone resin is discharged from the injection nozzle while relatively moving the thin metal sheet and the injection nozzle to form a silicone resin layer of a specific shape, and the opposite surface is formed. There is a method of forming a silicone resin thin film layer by a screen printing method.

A specific method of forming the silicone resin layer is as follows. A syringe in which the surface of a thin metal plate is filled with silicone resin in advance is moved by an XY robot while being discharged from a needle-like nozzle at the tip of the syringe by air pressure to form a linear shape. An example of a method of applying is shown. In this case, a method in which only the syringe is moved with the metal sheet fixed, or a method in which the syringe is moved while the metal sheet is moved uniaxially may be used. On the opposite surface of the metal sheet on which the silicone resin is formed, screen printing of the silicone resin is performed using a screen plate capable of printing a thin film on a portion corresponding to the position of the formed silicone resin layer on the front side.

After the silicone resin layer and the silicone resin thin film layer are formed on the surface opposite to the surface of the metal thin plate by the above-described method, crosslinking is performed by a curing method according to the characteristics of the resin. The crosslinking method may be any method such as heat curing, room temperature curing, ultraviolet curing, and electron beam curing.

In the present invention, the silicone resin used for the silicone resin layer formed on the surface of the metal thin plate by the above-mentioned discharge method is a liquid silicone resin, and a two-part type addition silicone liquid is a common addition type liquid silicone resin. A resin having a viscosity of 10 to 8000 poise (25 ° C.) can be suitably used. In the ejection formation from the ejection nozzle on the surface, if the viscosity is less than 1000 poise, the thickness cannot be maintained due to the flow after ejection, and if the viscosity exceeds 8,000 poise, the ejection becomes difficult, and the fluidity after ejection is insufficient, and the bonding area is insufficient. Is likely to decrease.

Further, in forming a thin film by screen printing provided on the opposite surface of the above-mentioned metal thin plate, a viscosity of 10 to 5 is used.
A 2,000 poise (25 ° C.) silicone resin can be suitably used. If the viscosity is less than 10 poise, the screen plate will pass through before printing, and if the viscosity exceeds 5000 poise, it will be difficult for the plate to pass through during printing. Further, a filler such as finely powdered silica, diatomaceous earth, or a high thermal conductive inorganic filler may be added to the silicone resin as needed.

Incidentally, it is preferable to provide various primer layers on the surface of the metal sheet 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 0.
It is preferably in the range of 01 μm to 5.0 μm,
If it is less than 0.01 μm, it is difficult to adjust the coating thickness,
If it exceeds 5.0 μm, the effect of improving the adhesion is small. Further, instead of the two-pack type, a one-pack type room-temperature-curable silicone resin having self-adhesiveness can also be used.
In this case, it is not necessary to provide the above-mentioned primer layer.

The present invention is characterized in that a silicone resin layer is discharged onto a surface of a metal thin plate while moving an injection nozzle to form a specific shape, and a silicone resin thin film layer is formed on the opposite surface by screen printing. The thickness of the silicone resin layer after injection molding from the injection nozzle is 0.05 mm
It is preferably in the range of 1.0 mm, 0.05 mm
If it is less than 1.0, the elasticity effect is not easily obtained, and the use as a packing material is inferior. If it exceeds 1.0 mm, it is difficult to reduce the size of the fuel cell, especially for a separator of a polymer electrolyte fuel cell, and the cost is high. Easy to be. The thickness of the silicone resin thin film layer on the opposite side is 0.01 mm to 0.05
If the thickness is less than 0.01 mm, there is a risk of generating voids. If the thickness exceeds 0.05 mm, the curing time becomes longer, and air bubbles are liable to be mixed during printing.

Further, the hardness of the silicone resin layer formed by the above method is preferably in the range of 10 to 70, preferably 20 to 60. (Measurement method of hardness is JIS
Performed in accordance with K6301 spring type hardness test A type. If the hardness is less than 10, the rubber repulsion force is low and the initial sealing force is insufficient, resulting in poor sealing. If it exceeds 70, the rubber tends to be too hard and lack elasticity.

The 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 preferably used for separators of fuel cells (polymer electrolyte fuel cells). it can. Such separators are required to be more miniaturized, and since a large number of separators are used in an overlapping manner, a separator having excellent precision and good productivity is required, and the metal composite of the present invention is required to meet such requirements. Is easy to satisfy.

[0017]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. (Example) Primer treatment (“X” manufactured by Toshiba Silicon Corporation)
P81-B0016 ”), a 1.0 mmt stainless steel plate (1.0 mm thick) was placed on a movable stage, and the capacity was 5 mm.
After defoaming in a 0 cc syringe, the filled silicone resin was linearly applied to a specific shape using a three-axis robot to form a silicone resin layer. The application was performed at a discharge air pressure of 2.0 kg / cm 2 using a needle-shaped nozzle having an inner diameter of 1.5 mm. "KE-1950-60" manufactured by Shin-Etsu Chemical Co., Ltd. was used as the liquid silicone resin.

After the application, the substrate is placed in a drying oven and is heated at 160 ° C. × 2
After curing under heating conditions for one minute, it is placed on the stage of a flat screen printing machine (FANAS company FA-1), and specified using a screen plate of stainless mesh # 60 and milk thickness of 300 μm on the opposite surface of the stainless steel plate. The shape silicone resin thin film layer was screen printed. Then, the composition was cured in a drying furnace under heating conditions of 160 ° C. × 2 minutes to obtain a fuel cell separator. The hardness of the silicone resin layer was 60. The obtained fuel cell separator has good adhesion between the stainless steel sheet and the silicone resin layer without peeling, and when the fuel cell is assembled using the separator, the sealing property (adhesion) between the separators is good. There was no problem in performance as a fuel cell separator.

[0019]

According to the metal composite of the present invention and the method for producing the same, the removal of burrs required in the injection molding method becomes unnecessary, and the multi-piece manufacturing is facilitated, so that the productivity is extremely good. Particularly, a fuel cell separator has an advantage that the production speed is significantly reduced. In addition, when used in stacking, a specific shape portion on the front surface is in contact with the silicone resin thin film layer on the back surface, so that the sealing property (adhesion) is very good, and a fuel cell separator with no internal gas leakage can be manufactured.
As described above, the metal composite manufacturing method of the present invention has an advantage that the metal composite can be manufactured accurately and efficiently, and the obtained metal composite has cushioning materials for various electric / electronic parts, It has great utility as a packing material and a spacer, particularly as a separator for a fuel cell (polymer electrolyte fuel cell).

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Claims (4)

[Claims] 1. A silicone formed by discharging a silicone resin from an injection nozzle on one side of a thin metal plate to form a silicone resin layer of a specific shape, and forming a silicone resin thin layer by screen printing on the opposite surface of the thin metal plate. Resin-coated metal composite. 2. An injection nozzle is provided in the vicinity of one side of a metal sheet, and while the metal sheet and the injection nozzle are relatively moved, a silicone resin is discharged from the injection nozzle to form a silicone resin layer of a specific shape. A method for producing a silicone resin-coated metal composite, wherein a silicone resin thin film layer is formed by screen printing. 3. The silicone resin layer to be formed has a thickness of 0.
It is characterized in that the hardness (JIS K6301 spring type hardness test A type) is in the range of 10 to 70 and the viscosity of the silicone resin at 25 ° C. when uncured is in the range of 10 to 8000 poise. The silicone resin-coated metal composite according to claim 1 or 2, and a method for producing the same. 4. The silicone resin-coated metal composite according to claim 1, which is used for a separator of a fuel cell, and a method for producing the same.