JP3638540B2 - Buffer sheet for hot press - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cushioning sheet such as a cushioning material interposed between a hot platen of a press machine and a glass substrate heated and pressed for bonding, for example, during hot pressing in an assembly process of a liquid crystal cell, and a method for manufacturing the same. It is.
[0002]
[Prior art]
A liquid crystal cell used as a liquid crystal display panel is formed by arranging two glass substrates provided with electrodes with a predetermined gap, and curing and sealing the adhesive printed on the periphery by pressure heating. It is assembled. During pressurizing and heating in this assembly process, it is an object to be pressed on the upper and lower surface plates of the press machine in order to avoid local load concentration on the glass substrate and stably maintain the fine spacing between the glass substrates. Japanese Unexamined Utility Model Publication No. 5-36425 discloses that a buffer material is interposed on the contact surface of the glass substrate. However, this cushioning material is not always attached and fixed to the surface plate, particularly the upper surface plate.
[0003]
On the other hand, JP-A-10-151703 discloses a buffer for hot press in which a cushion layer made of silicone rubber sponge and a magnetic layer made of magnetic rubber sheet are integrated through an adhesive layer made of nonwoven fabric as this kind of buffer material. A sheet is disclosed, and is a buffer material magnetically attached to the upper and lower heating plates using the magnetic layer, and is particularly characterized in that it can be always fixed to the upper heating plate.
[0004]
[Problems to be solved by the invention]
However, in recent years, there has been a tendency for the material of the hot platen of the press machine to be changed from iron to graphite with higher thermal conductivity and lower thermal expansion. Since it cannot be attached, there has been a problem in that it is necessary to change the mounting method to a simple hot plate using the magnetic layer in the conventional buffer sheet.
[0005]
An object of the present invention is to provide a shock-absorbing sheet that can be easily attached to a graphitized hot plate and a method for manufacturing the same.
[0006]
[Means for Solving the Problems]
Buffer sheet to be interposed between the press and the press object of the present invention, a cushion layer composed of a heat resistant sponge rubber layer thick, press consisting of thin solid rubber layer adhered integrally on one surface of the cushion layer The mounting layer is formed by laminating an unvulcanized heat-resistant rubber coated on a transfer film on a heat-resistant sponge rubber layer, and vulcanizing and molding by pressurization and heat-resistant sponge rubber. It is a thin solid rubber layer that is bonded and integrated with the layer, and then the transfer film is peeled off. The contact surface with the heating plate is given adhesive force by transfer of the glossy surface of the transfer film, and the adhesive force causes the heat It can be fixed to the board. Specifically, the buffer sheet is interposed as a cushioning material between the hot platen of the press machine and the glass substrate in the liquid crystal cell assembly process.
[0007]
Moreover, the buffer sheet according to the present invention, the cushion layer is a heat-resistant sponge rubber layer unvulcanized heat-resistant rubber sheet obtained by vulcanized foam molding containing a blowing agent, coated with unvulcanized heat-resistant rubber the transfer film which is preferably a large plastic film gloss.
[0008]
The cushion sheet manufacturing method according to the present invention includes a cushion layer molding step of vulcanizing and foaming an unvulcanized rubber sheet containing a foaming agent into a thick sponge rubber layer, and coating the transfer film with unvulcanized rubber. Forming a thin unvulcanized rubber sheet, and laminating the thin unvulcanized rubber sheet on the thick sponge rubber layer, and pressurizing and heating to vulcanize and simultaneously form the thick sponge rubber layer. It includes an attachment layer forming step for bonding and integration, and a step for peeling the transfer film to expose the transfer surface of the attachment layer.
[0009]
In the present invention, the cushion layer that is the main component of the cushioning sheet is formed of a thick sponge rubber layer, and the surface that contacts the hot platen is attached by a thin solid rubber layer whose adhesion has been enhanced by transfer of a transfer film. Regardless of whether the heating plate is made of iron or graphite, the heating plate can be always fixed to the heating plate, especially the upper heating plate, regardless of whether the heating plate is made of iron or graphite, and no separate mounting means is required.
[0010]
【Example】
Hereinafter, an embodiment in which the buffer sheet for hot press according to the present invention is used as a cushioning material for assembling a liquid crystal cell will be described with reference to the accompanying drawings.
[0011]
FIG. 1 shows a state in which heat and pressure are applied by upper and lower heating plates 12 and 12 of a press machine in order to bond two upper and lower glass substrates 11 and 11 in an assembly process of a liquid crystal cell. Cushion materials 1 and 1 are interposed between the upper and lower sides of 11 and 11, respectively. With the cushion materials 1, 1, the sealing material 13 between the glass substrates 11, 11 is uniformly crushed, and the gap between the upper and lower glass substrates 11, 11 is kept constant. Reference numeral 14 denotes a spacer interposed between the glass substrates 11 and 11.
[0012]
The cushion material 1 is formed by bonding and integrating a cushion layer 2 made of a thick sponge rubber layer and a mounting layer 4 made of a thin solid rubber layer laminated on one surface of the cushion layer 2.
[0013]
2 and 3 show the manufacturing process of the cushion material 1. FIG. 2 shows molding of a solid rubber layer constituting the attachment layer 4 forming one side of the cushion material 1, and heat-resistant rubber such as unvulcanized silicone rubber compound 6 is rolled into a sheet by an inverted L-shaped calendar 15. The unvulcanized thin-walled solid rubber sheet 4 being molded and the transfer film 5 continuously supplied in the direction of the arrow are pressed between the pair of rolls 16 and 16 of the inverted L-shaped calendar 15 by rolling.
[0014]
As the transfer film 5, a plastic film, for example, a PET film having a high glossiness specified by JIS K7105 (for example, product name Emblet (SA-100, TA-100, etc.) manufactured by Unitika Ltd.) is used. The rubber sheet 4 is pressed and transferred onto the surface. As an effect of this transfer, the adhesive force on the surface of the rubber sheet 4 which finally becomes the attachment layer is remarkably increased. As the PET film having a high glossiness, a film having a 60 ° specular glossiness of 70% or more, more preferably 100% or more can be selected.
[0015]
The unvulcanized thin solid rubber sheet 4 with the topping coated on the transfer film 5 as described above, and the unvulcanized silicone rubber sheet containing a foaming agent in a separate process is vulcanized and foamed by press molding or the like. It is laminated on the silicone sponge rubber layer 2 (see FIG. 3A). Thin skin layers 3 and 3 are formed on the surface of the silicone sponge rubber layer 2. After the lamination, pressure is heated by a press machine (not shown) to vulcanize and form an unvulcanized thin solid rubber sheet 4 with the transfer film 5 coated on the surface, and at the same time a thick silicone sponge rubber layer (cushion layer) ) 2 by vulcanization adhesion (see FIG. 3B). The integrated laminated sheet is further subjected to treatment such as secondary vulcanization as necessary.
[0016]
Thereafter, the transfer film 5 is peeled off from the laminated sheet, the surface 4a of the mounting layer 4 to which the gloss is transferred and the adhesive force is applied is exposed, and the final molding of the cushion material 1 is completed (FIG. 3C). reference). The attachment layer 4 is fixed by simply being in direct contact with the upper and lower heating plates 12, 12, and there is no possibility of peeling off from the upper heating platen 12. In the present embodiment, the thickness of the cushion material 1 as a whole is 5.0 mm, of which the thickness of the cushion layer 2 is 4.5 mm and the thickness of the mounting layer 4 is 0.5 mm.
[0017]
The present invention is not limited to the above embodiment, heat-resistant rubber other than silicone rubber can be used as the material constituting the cushioning material, and transfer film made of plastic other than PET film or other materials can be used as the transfer film. Other known methods can be used for coating the transfer film with thin rubber, and the thicknesses of the cushion layer and the attachment layer can be arbitrarily adjusted.
[0018]
【The invention's effect】
According to the buffer sheet of the present invention, it is possible to easily and firmly attach the mounting layer to the graphitized hot platen, and in particular, it is possible to perform hot-breathing work in a state of being always fixed to the upper hot platen, There is a practical value that can be expected to improve the molding efficiency.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of use of a buffer sheet according to the present invention.
FIG. 2 is a schematic view showing a coating process of a transfer film and a rubber sheet.
FIG. 3 is a cross-sectional view illustrating a buffer sheet forming step.
[Explanation of symbols]
1 Buffer sheet (cushion material)
2 Cushion layer (thick sponge rubber layer)
3 Skin layer 4 Mounting layer (thin solid rubber layer)
5 Transfer film 6 Rubber compound 11 Glass substrate 12 Hot platen

Claims (1)

A cushioning sheet interposed between a pressing machine and an object to be pressed, comprising a cushion layer made of a thick heat-resistant sponge rubber layer and a thin solid rubber layer bonded and integrated on one side of the cushion layer. A mounting layer to a heating plate, and the mounting layer is formed by laminating an unvulcanized heat-resistant rubber coated on a transfer film on a heat-resistant sponge rubber layer, and vulcanizing and molding by pressure heating at the same time. A thin solid rubber layer that is bonded and integrated with the transfer film, and then the transfer film is peeled off. The contact surface with the heat plate is given adhesive force by transfer of the glossy surface of the transfer film. A buffer sheet for hot pressing, characterized in that it can be fixed to a hot press.

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