JP2023148013A - Press pressure control method of composite sheet, and composite sheet - Google Patents

Abstract

To apply a pressure uniformly onto a workpiece surface through a composite sheet, when processing a workpiece by pressing the composite sheet containing silicone rubber on the surface of the workpiece.SOLUTION: A three-dimensionally shaped composite sheet 1 is used, which is formed by differentiating thickness of a silicone rubber layer 11 according to a pressure distribution of a pressure applied onto a workpiece 2 when being pressed, and this is pressed onto the workpiece 2 surface, to thereby control a pressure applied onto the workpiece 2 surface. The thickness of the silicone rubber layer 11 is allowed to correspond to a rugged shape on the workpiece 2 surface, and an area with a high pressure is set to be thin, and an area with a low pressure is set to be thick.SELECTED DRAWING: Figure 1

Description

The present invention provides pressure applied to the surface of the workpiece through the composite sheet when the workpiece is processed by pressurizing a composite sheet containing silicone rubber onto the surface of the workpiece (hereinafter also referred to as "workpiece"). Concerning how to control.

Composite sheets containing silicone rubber are used as sheets for processing work surfaces in various industrial fields.

For example, FIG. 6 shows a processing mode in which a Fresnel lens is manufactured by pressurizing a composite sheet onto the surface of a workpiece.
What is shown in the figure is a workpiece, which is a transparent glass plate 102, a composite sheet 103 containing silicone rubber, and a Fresnel lens on the surface, between a fixed platen 101a and a movable platen 101b of a pressure press 101. A master mold 104 with a concavo-convex pattern formed thereon is placed, the movable platen 101b is lowered, and the concavo-convex pattern of the master mold 104 is transferred and formed on the surface of the composite sheet 103 by pressing at a predetermined pressure and temperature. At the same time, the composite sheet 103 is bonded to the workpiece 102 under heat and pressure, and then the movable platen 101b is raised to release the master mold 104 from the cured composite sheet 103 to obtain a Fresnel lens (for example, patent (See Reference 1).

Japanese Patent Application Publication No. 2007-212771

When processing a workpiece by stacking a composite sheet on the surface of the workpiece and pressing it with a pressure press machine as described above, if the workpiece has an uneven surface, the composite sheet is sandwiched between the workpiece and the workpiece. The pressure applied to the concave portion of the press and the pressure applied to the convex portion may be different, or the pressure applied to the workpiece through the composite sheet may be different between the center and the periphery of the press, that is, the center and periphery of the workpiece. Pressure may not be applied evenly throughout.
In a processing mode in which a composite sheet is heat-pressed to a workpiece, the pressure applied to the workpiece is unevenly distributed, resulting in insufficient pressure-bonding of the composite sheet to the workpiece, resulting in processes such as peeling of the composite sheet from the workpiece or partial lifting of the sheet. Defects may occur.

In view of such problems in the prior art, the present invention has been developed to process a workpiece by pressurizing a composite sheet containing silicone rubber on the surface of the workpiece, regardless of the surface shape of the workpiece. The objective is to apply pressure uniformly to the surface of the workpiece.

When processing a workpiece by pressurizing a composite sheet onto the surface of the workpiece, the pressure press machine partially applies pressure to the workpiece as a means to equalize the pressure applied to the workpiece through the composite sheet. One option is to provide a function to adjust the temperature, but the mechanism would be complicated and would be impractical. When the pressing force of a pressure press is constant over the entire workpiece, conventionally used composite sheets with uniform thickness disperse the pressing force in accordance with the uneven shape of the workpiece surface. cannot be adjusted so that pressure is applied uniformly.

Therefore, in the present invention, instead of the conventional composite sheet with a uniform thickness, we use a composite sheet with partially different thicknesses corresponding to the uneven shape of the workpiece surface, which is stacked on the workpiece surface and pressed under pressure. This effectively disperses the pressure applied to the surface of the workpiece when the work is done, so that the pressure is evenly applied to the entire workpiece.

That is, the press pressure control method for a composite sheet of the present invention is such that when processing a workpiece by pressure-pressing a composite sheet containing a silicone rubber layer and a synthetic resin film layer onto the workpiece surface, the pressure control method applies pressure to the workpiece surface through the composite sheet. This is a method of controlling the pressure applied to the workpiece, using a three-dimensional composite sheet formed by varying the thickness of the silicone rubber layer depending on the pressure distribution of the pressure applied to the workpiece during the pressure pressing. It is characterized by controlling the pressure applied to the work surface by pressurizing the work surface.

The distribution of the pressure applied to the workpiece during pressurization is the magnitude of the pressure applied to the workpiece surface when a conventional composite sheet with a flat surface and constant thickness is pressurized onto the workpiece surface. can be obtained by observing and evaluating.
For example, when a workpiece has a shape with convexities and concave parts on its surface, if a composite sheet of a certain thickness is stacked on top of the workpiece and pressure-pressed, a large pressure will be applied to the area of the workpiece where the convexities are provided. This makes it difficult for pressure to be applied to the area where the recessed portion is provided. Based on this pressure distribution, the thickness of the silicone rubber layer is reduced in the area of the composite sheet that is in contact with the area where the applied pressure is large, and the thickness of the silicone rubber layer is increased in the area that is in contact with the area where the applied pressure is small. A composite sheet is formed by setting the thickness of the area overlapping the convex portions to be small and the thickness of the area overlapping to the concave portions to be large, and when this is pressure-pressed onto a workpiece, the pressure is controlled to be applied uniformly to the surface of the entire workpiece. becomes possible. The pressure dispersion performance of the composite sheet can be improved by providing the composite sheet containing silicone rubber in a three-dimensional shape with partially different thicknesses instead of having a constant thickness.

The composite sheet formed by partially varying the thickness according to the pressure distribution applied to the workpiece is, for example, a composite sheet formed by reducing the thickness of the silicone rubber layer in the plane in contact with the workpiece surface. At least one concave portion that is not open is provided in the periphery. This concave portion is provided so as to be in contact with an area of the workpiece where the pressing pressure is high when the composite sheet is pressed onto the workpiece surface.
How to appropriately arrange the concave portions and set the thickness of the composite sheet can be determined by performing a structural analysis simulation to determine the pressure applied to the workpiece surface during pressure pressing, depending on the shape of the workpiece surface, etc. can be determined.

(Composition of composite sheet)
The composite sheet is a silicone rubber composite in which a silicone rubber layer made of a silicone elastomer resin is formed on at least one side of a sheet or film mainly made of crystalline polyester resin, so that the sheet or film and the silicone rubber layer are integrated. can be used.

Preferably, on one side of a base layer (layer A) mainly composed of a crystalline polyester resin, an undercoat layer (layer B) containing an amorphous polymer, a thin film layer (layer C) containing a silicone resin, It is a silicone rubber composite formed by laminating and integrating silicone rubber layers (D layer) containing silicone elastomer resin in the order, and the center line average of the other side different from the one side of the base material layer (A layer). A silicone rubber composite having a roughness (Sa) of 1.0 μm or more can be used.
Hereinafter, the structure of an example of a silicone rubber composite (hereinafter also referred to as "main composite") suitably used as the composite sheet will be described.

Because this composite is laminated with silicone rubber and a base material layer (layer A) mainly composed of crystalline polyester resin, it does not wrinkle or bend, and when used as a mold release material for press molding, it can be molded easily. It can improve your body's productivity. Furthermore, when forming a silicone rubber composite by winding it into a roll or stacking it in a sheet, it is important to ensure that the silicone rubber composites are in close contact with each other, that is, the base layer (layer A) and the silicone rubber layer (D layer). Deterioration in workability due to adhesion with the layer) can be improved.

[Base material layer (A layer)]
The main component of the base material layer (layer A) is a crystalline polyester resin from the viewpoint of heat resistance and mechanical strength. Examples of the crystalline polyester resin include polyethylene terephthalate, polyethylene naphthalate, and the like. Among these, polyethylene terephthalate is preferred from the viewpoint of heat resistance, film stiffness, smoothness, commercial availability, and adhesiveness with other layers.
Further, from the viewpoint of mechanical strength, the base material layer (layer A) is preferably oriented at least uniaxially, and more preferably stretched biaxially.

The thickness of the base material layer (layer A) is preferably 10 μm to 350 μm, more preferably 15 μm to 300 μm, even more preferably 20 μm to 250 μm. By setting the thickness to 10 μm or more, the occurrence of wrinkles etc. can be sufficiently suppressed when another layer is laminated on the surface. On the other hand, by setting the thickness to 350 μm or less, the base layer (layer A) does not become too hard, so it tends to be easier to coat an undercoat layer, etc., which will be described later.

The surface roughness of the base material layer (layer A) is determined at the center on the other side, which is different from the one side on which the undercoat layer (layer B), thin film layer (layer C), and silicone rubber layer (layer D) described below are laminated. It is important that the line average roughness (Sa) is 1.0 μm or more, preferably 2.0 μm or more, more preferably 10 μm or more. By setting the Sa to 1.0 μm or more, when the silicone rubber composites are stacked on top of each other, the base material layer (layer A) and the silicone rubber layer (layer D) described below are unlikely to be in excessive contact with each other. Therefore, when forming a silicone rubber composite that is rolled into a roll or stacked in sheets, the base material layer (layer A) and the silicone rubber layer (layer D) are too closely attached. Problems such as difficulty in peeling off of the silicone rubber composite can be suppressed. This is because by roughening the surface of the base layer, the contact area between the silicone rubber composites, that is, between the base layer (A layer) and the silicone rubber layer (D layer), becomes smaller. It is thought that even if they are stacked, they will peel off easily. On the other hand, the upper limit of the center line average roughness (Sa) is not particularly limited, but from the viewpoint of smoothness, it is preferably 300 μm or less, and more preferably 200 μm or less.
The centerline average roughness (Sa) is the average of the absolute values of the differences in height of each point with respect to the average surface of the surface, and is based on ISO25178.

In order to make the centerline average roughness (Sa) 1.0 μm or more, it is important to roughen the other side of the base material layer (layer A), which is different from one side. A known method can be applied to the surface roughening method. Specific methods for roughening the surface include physical methods such as corona treatment, plasma treatment, sandblasting, embossing, and laser ablation, and chemical methods such as corrosion treatment using chemicals such as solvents. Among these, sandblasting and laser ablation are preferred from the viewpoint of productivity.

[Undercoat layer (B layer)]
This composite has an undercoat layer (layer B) containing an amorphous polymer on one side of the base layer (layer A). By using the undercoat layer (B layer), the thin film layer (C layer) can be uniformly formed.

The amorphous polymer is not particularly limited as long as it can be applied uniformly to the surface of the base layer (layer A), and may be substantially crystalline, such as polyurethane resin, acrylic resin, or amorphous polyester resin. The polymer may be appropriately selected from polymers having no properties.
Specific examples include polyurethane resins made by increasing the molecular weight of polyester resins and/or polyether resins into linear chains with urethane bonds, acrylic resins made from copolymers of acrylic acid and/or methacrylic esters, acid components, or glycols. Examples include copolyester resins whose components are composed of two or more types of monomers. Since these amorphous resins are applied to a thin film, they are usually used diluted with an organic solvent or emulsified or solubilized in water to adjust the concentration to an appropriate level.

The undercoat layer (layer B) may have a crosslinked structure for the purpose of improving heat resistance and solvent resistance. In this case, the amorphous polymer has a carboxyl group in the main chain or side chain. , hydroxyl group, amino group, etc., and the crosslinking agent is appropriately selected from polyisocyanate, melamine, polyfunctional epoxy resin, metal compound, etc. Further, in addition to the above-mentioned crosslinking agent, the coating liquid may contain a leveling agent such as a surfactant, an antiblocking agent such as silica, a thickener, and the like.

The thickness of the undercoat layer (layer B) is preferably 0.01 to 5 μm. If the thickness of the undercoat layer (B layer) is 0.01 μm or more, it is preferable because the thickness can be easily adjusted and the adhesiveness with the thin film layer (C layer) containing a silicone resin described below is also good. . Moreover, if the thickness is 5 μm or less, coating of the undercoat layer (B layer) will not become difficult. From this point of view, the thickness of the undercoat layer (layer B) is more preferably 0.05 to 4 μm, and even more preferably 0.1 to 3 μm.

[Thin film layer (C layer)]
In this composite, a thin film layer (C layer) is further formed on the undercoat layer (B layer). The thin film layer (C layer) contains silicone resin, and among them, it has a high affinity for the undercoat layer (B layer) and forms a crosslinked film by heating or UV irradiation after application, and silicone resin It is preferable to form a crosslinked film at the same time as the rubber layer (layer D) is crosslinked.

Examples of silicone resins that can be used for the thin film layer (C layer) include addition-type silicone resins, condensation-type silicone resins, and UV-curable silicone resins.
Examples of addition-type silicone resins include those obtained by using polydimethylsiloxane containing vinyl groups as a base polymer, blending polymethylhydrogensiloxane as a crosslinking agent, and curing the resin by reaction in the presence of a platinum catalyst. Examples of condensation type silicone resins include those obtained by using polydimethylsiloxane containing a silanol group at the terminal as a base polymer, blending polymethylhydrogensiloxane as a crosslinking agent, and curing by heating in the presence of an organotin catalyst. .

Examples of UV-curable silicone resins include those whose base polymer is polydimethylsiloxane containing an acryloyl group or methacryloyl group, those whose base polymer is polydimethylsiloxane containing a mercapto group and a vinyl group, and the above-mentioned addition type silicone resins. Alternatively, examples include those in which a photopolymerization initiator is blended into a base polymer made of polydimethylsiloxane containing an epoxy group that hardens by a cationic curing mechanism, and the mixture is cured by irradiation with UV light.

Moreover, it is preferable that the coating liquid contains an additive such as a silane coupling agent for the purpose of increasing the affinity with the undercoat layer (layer B). A silane coupling agent that satisfies this purpose is a compound represented by the general formula YRSiX3, where Y is an organic functional group such as a vinyl group, epoxy group, amino group, or mercapto group, and R is an alkylene group such as methylene, ethylene, or propylene. X is a hydrolyzable functional group such as a methoxy group or an ethoxy group, or an alkyl group. Specific compounds include, for example, vinyltriethoxysilane, vinyltrimethoxysilane, γ-glycidylpropyltrimethoxysilane, γ-glycidylpropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N- Examples include β(aminoethyl)-γ-aminopropylmethyldimethoxysilane and γ-mercaptopropyltrimethoxysilane.

The thickness of the thin film layer (C layer) is preferably 0.01 to 1 μm after solvent drying. When the thickness is 0.01 μm or more, a cured film with a uniform thickness can be obtained, and sufficient adhesive strength with the silicone rubber layer (D layer) can be obtained. In addition, since silicone resins with the above composition generally do not have very strong film strength, when evaluating the peel strength of this composite, cohesive failure tends to occur in the thin film layer (C layer); If so, cohesive failure of the thin film layer (C layer) can be suppressed and sufficient strength can be obtained as a silicone rubber composite. From this viewpoint, the thickness of the thin film layer (C layer) is more preferably 0.03 to 0.7 μm, and even more preferably 0.05 to 0.5 μm.

[Silicone rubber layer (D layer)]
The silicone rubber layer (D layer) is characterized by containing a silicone elastomer resin.
As an example of the silicone elastomer resin that can be used for the silicone rubber layer (layer D), a silicone elastomer resin containing polydimethylsiloxane as a main component is preferably mentioned.
Further, it is also preferable from the viewpoint of adjusting the compression set that the silicone rubber layer (D layer) contains a silicone elastomer resin whose main component is polydimethylsiloxane containing a vinyl group. When containing a vinyl group, the content of the vinyl group based on the total amount of polydimethylsiloxane is preferably 0.05 to 5 mol%, more preferably 0.5 to 4 mol%, and 1 to 3 mol%. More preferably, it is mol%. When the content of vinyl groups is 0.05 mol%, the crosslinking density of the silicone elastomer resin can be easily adjusted, and a silicone elastomer resin having a desired compression set can be obtained. On the other hand, if it is 5 mol% or less, the silicone elastomer resin will not be cured excessively, which is preferable.

Commercially available products can also be used as such silicone elastomer resins. As commercially available products, a millable silicone compound manufactured by Shin-Etsu Chemical Co., Ltd. and a millable silicone rubber manufactured by Momentive Performance Materials can be used.

Here, silicone elastomer resin includes reinforcing fillers such as fumed silica, precipitated silica, diatomaceous earth, and quartz powder, various processing aids, and heat resistance improvers, as well as various additives that give it functionality as an elastomer. It may also contain an agent. Examples of the additives include flame retardant agents, heat dissipating fillers, conductive fillers, and the like.

The thickness of the silicone rubber layer (D layer) is preferably 50 μm or more. When the thickness is 50 μm or more, the present composite can sufficiently exhibit rubber elastic properties. Further, the lower limit of the thickness is preferably 1.5 mm or less in view of the intended use.

The silicone rubber layer (D layer) preferably has a hardness of 10 to 80, more preferably 20 to 70, when the silicone elastomer resin is cured. When the hardness is 10 or more, the present composite can have sufficient handling properties, and when the hardness is 80 or less, it can have sufficient elasticity.
The hardness measurement method is based on JIS K6301 spring type hardness test type A.

[Laminated structure]
The laminated structure of the present composite is such that layer A/layer B/layer C/layer D are laminated in this order and integrated. Alternatively, other layers such as a protective layer may be laminated on the surface of the silicone rubber layer (layer D), if necessary.

[Peeling properties]
The peeling force between the composites at room temperature is preferably 0.03 mN/20 mm or less, more preferably 0.02 mN/20 mm or less. On the other hand, the lower limit is not particularly limited from the viewpoint of release characteristics.
When using this composite as a mold release material, the lower the peeling force at room temperature, the less force is required when peeling the composites together during processing of the composite. Problems such as body deformation can be suppressed. Among these, the present composite can suppress the above-mentioned problems and have low peeling properties even if there is a silicone rubber layer (D layer) that reduces the adhesiveness.

<Method for manufacturing silicone rubber composite>
The manufacturing method of this composite includes a base layer (layer A) containing a crystalline polyester resin as a main component, an undercoat layer (layer B) containing an amorphous polymer, and a thin film layer containing a silicone resin on one side. (Layer C) and a silicone rubber layer containing a silicone elastomer resin (Layer D) are laminated in this order and integrated.

First, a coating liquid as an undercoat layer (B layer) is applied to one side of the base material layer (A layer) mainly composed of the above-mentioned polyester resin, then dried, and further thermally crosslinked as necessary. In this way, an undercoat layer (layer B) is formed. As a coating method, a known method suitable for the coating liquid can be applied, and it may be applied to a base material layer (layer A) that has been stretched in a separate process, or it may be applied to an unstretched sheet of the base material layer (layer A). An undercoat layer (layer B) may be formed by directly applying a coating liquid and then stretching. Further, the coated surface may be subjected to surface treatment such as corona treatment in advance in order to improve the leveling properties and adhesion of the coating liquid.

Next, a thin film layer (C layer) is applied on the undercoat layer (B layer). As with the undercoat layer (layer B) described above, the coating method is not particularly limited as long as a thin film can be obtained with high precision, and any known method can be used.

Furthermore, the silicone rubber layer (D layer) containing a silicone elastomer resin is preferably laminated by the following method. First, an uncrosslinked silicone elastomer resin is laminated on a thin film layer (C layer) containing a silicone resin. As for the lamination method, it is preferable to form an uncrosslinked silicone elastomer resin into a sheet by extrusion molding, injection molding, calendar molding, press molding, etc., and then laminate it on the thin film layer (C layer). Alternatively, the film may be directly formed on the thin film layer (C layer) by a known coating method.

Next, the present composite can be obtained by curing the uncrosslinked silicone elastomer resin. Examples of methods for curing the silicone elastomer resin include a method of adding a curing catalyst, a method of heating at high temperature, a method of adding a crosslinking agent, and a method of crosslinking by radiation irradiation.

Among these, the silicone rubber layer (D layer) of the present composite is preferably a radiation cured product cured by radiation irradiation. Curing by radiation irradiation is preferable because there is no concern that heat resistance and light resistance reliability will be impaired due to residues of the catalyst or crosslinking agent. Further, since no heat is applied during curing, there is no fear of thermal deterioration, which is preferable.

Examples of the radiation include electron beams, X-rays, and gamma rays. These radiations are widely used industrially, are easily available, and are energy efficient methods. Among these, it is preferable to use gamma rays from the viewpoint of almost no absorption loss and high transparency.

The irradiation dose of γ-rays can be appropriately selected and determined depending on the type of resin, the amount of crosslinking groups, and the type of radiation source. In the present composite, the γ-ray irradiation dose is preferably 20 to 150 kGy, for example. If the irradiation dose is 20 kGy or more, the silicone rubber layer (D layer) can be sufficiently cured, and as a result, desired compression set can be obtained. On the other hand, if the irradiation dose is 150 kGy or less, the increase in low molecular weight components due to decomposition reactions can be suppressed. From this point of view, the irradiation dose is more preferably 30 to 120 kGy, and even more preferably 40 to 110 kGy.

In addition, in selecting the irradiation dose, it is necessary to take into account the crosslinking density of the silicone elastomer resin as well as the radiation resistance of the plastic film used as the base layer (layer A). In this regard, the crystalline polyester resin used in the present composite generally has excellent resistance to radiation and is a base material that is extremely suitable for the purpose of the present invention.

(Method for manufacturing composite sheet)
As mentioned above, based on the magnitude of the pressure applied to the surface of the workpiece when the composite sheet is stacked on the workpiece and pressurized, the areas where pressure is unevenly distributed are observed and evaluated, and the areas of the workpiece where pressure is likely to be applied are determined. The three-dimensional shape of the composite sheet is determined so that the thin part of the composite sheet overlaps with the thin part of the composite sheet, and the thick part of the composite sheet overlaps with the area where pressure is not easily applied.
The production of a three-dimensional composite sheet can be carried out, for example, by pressing the uncured silicone rubber sheet of the present composite against a shaping roll, adjusting the thickness of the silicone rubber layer as appropriate, and forming the silicone rubber layer. This can be done by providing a three-dimensional shape such as a concave portion or a convex portion.

In the above description, the expression "main component" includes the meaning of allowing other components to be included as long as they do not interfere with the function of the main component, unless otherwise specified.
At this time, although the content ratio of the main component is not specified, the main component (if two or more components are the main components, the total amount of these components) is 50% by mass or more, preferably 70% by mass in the composition. It accounts for at least 90% by mass, particularly preferably at least 90% by mass (including 100%).
In addition, when expressed as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, it means "more than or equal to X and less than or equal to Y", and also means "preferably greater than ”.
Furthermore, when expressed as "more than or equal to X" (where X is any number), unless otherwise specified, it includes the meaning of "preferably greater than X" and is expressed as "less than or equal to Y" (where Y is any number). "preferably smaller than Y" is included unless otherwise specified.

Additionally, in general, a "sheet" is defined as a flat product that is thin and has a small thickness compared to its length and width, and a "film" generally refers to a flat product that is thin compared to its length and width. A thin, flat product with an extremely small thickness and an arbitrarily limited maximum thickness, usually supplied in the form of a roll (JIS K6900:1994). However, the boundary between "sheet" and "film" is unclear, and there is no need to distinguish between the two in terms of the wording in the present invention. However, "film" is also included.

According to the present invention, by stacking a composite sheet with partially different thicknesses on a workpiece and pressurizing it, it is possible to control the pressure applied to the workpiece surface through the composite sheet so that it is uniform over the entire workpiece. The pressure can be increased or decreased at specific points within the body. In the process of heat-pressing a composite sheet onto a workpiece, it eliminates the uneven distribution of pressure on the workpiece, improves the adhesion of the composite sheet to the workpiece, and prevents the composite sheet from peeling off from the workpiece or partially lifting. It is possible to suppress processing defects.

FIG. 2 is a diagram showing a schematic cross section of a composite sheet. FIG. 3 is a diagram showing a schematic cross section of a composite sheet of a comparative example. It is a figure showing the pressure distribution on the workpiece surface in a comparative example. FIG. 2 is a diagram showing a schematic cross section of a composite sheet of an example. It is a figure showing pressure distribution on the workpiece surface in an example. 1 is a diagram showing an example of a conventional processing mode in which a composite sheet is pressure-pressed onto a workpiece surface.

A method of controlling press pressure for a composite sheet according to the present invention will be described by exemplifying an embodiment. Note that the present invention is not limited to the following embodiments.

FIG. 1 shows the structure of a composite sheet used in the present invention.
The composite sheet 1 is the aforementioned silicone rubber composite, and is constructed by laminating a silicone rubber layer 11 and a synthetic resin film layer 12 made of a biaxially stretched polyester film.
As described above, the composite sheet 1 was obtained by observing and evaluating the areas where the pressure was unevenly distributed according to the pressure distribution applied to the workpiece surface when it was stacked on the workpiece 2 and pressurized. is processed into a three-dimensional shape with partially different thicknesses.
In the process of hot-pressing the composite sheet onto the surface of the workpiece, the three-dimensionally shaped composite sheet 1 is stacked on the workpiece 2 and pressed under pressure, so that the pressure applied to the surface of the workpiece 2 is uniform throughout the workpiece. It becomes possible to control.

The following describes the results of a computer simulation of the pressure applied to the workpiece surface during pressure pressing with respect to a molded product formed by pressurizing the composite sheet onto the workpiece surface.

(Comparative example)
As shown in FIG. 2, a simulation was performed in which a composite sheet 1 with a flat surface and a constant thickness was stacked on a workpiece and pressed under pressure.
The conditions for the composite sheet were set as a 600 μm thick silicone rubber composite formed by bonding and integrating a 100 μm thick polyester film with an elastic modulus of 4.2 GPa on one side of a 500 μm thick silicone rubber layer. The silicone rubber was modeled as a superelastic body with an initial transverse shear modulus of 1 MPa.
The workpiece was a synthetic resin molded body that was square in plan view.
The silicone rubber layer side of the composite sheet is placed on the top surface of the workpiece, and the top surface of the workpiece is covered with the composite sheet, and this is applied with a pressure press with a uniform surface pressure (24.0 kgf/cm ² ) over the entire top surface of the composite sheet. The magnitude of the pressure applied to the workpiece surface when pressed was observed through simulation. The horizontal size of the workpiece or composite sheet was assumed to be 10 mm x 10 mm, and the analysis was actually performed using a 1/4 model of 5 mm x 5 mm. LS-DYNA was used as the structural analysis software.

FIG. 3 shows the results of the simulation, and shows the pressure distribution applied to the workpiece surface in the first quadrant when the upper surface of the workpiece is divided into four by the X-axis and Y-axis passing through the center.
As shown in the figure, the pressure applied to the surface of the workpiece was large in the central area of the workpiece, and small in the peripheral area away from the center of the workpiece. During actual pressure press processing, when a composite sheet of a certain thickness is used, there are areas within the workpiece where pressure is not applied sufficiently due to the uneven shape of the workpiece surface, which is a problem mentioned above. The simulation results are as follows.

(Example)
Instead of the composite sheet of the comparative example, the same simulation as above was performed using composite sheets with partially different thicknesses as shown in FIG.
In this composite sheet, the thickness of the silicone rubber layer of the same silicone rubber composite as in the comparative example is made the smallest in the part that contacts the central area of the workpiece, and gradually increases over the part that contacts the peripheral area of the workpiece. In other words, it is processed to have a cross-sectional shape with a concave center. The simulation conditions were the same as in the comparative example, except that the thickness of the composite sheet was partially different.

FIG. 5 shows the simulation results of the example, and shows the pressure distribution applied to the workpiece surface in the first quadrant when the workpiece top surface is divided into four parts as described above.
As shown in the figure, it can be confirmed that pressure is applied widely and substantially uniformly to the surface of the workpiece, from the central region to the near-periphery region of the workpiece.

The thickness of the composite sheet of the example was determined based on the pressure distribution applied to the workpiece surface when using the composite sheet of the comparative example with a constant thickness, and the thickness of the area in contact with the area where the pressure was high was decreased, and the pressure was low. The portion that contacts the area is formed to be large. In this way, by using a composite sheet with a three-dimensional shape that has partially different thicknesses that correspond to the uneven shape of the workpiece surface and the magnitude of the pressure applied to it, when the composite sheet is stacked on the workpiece and pressure-pressed. Furthermore, it was verified by the simulation results of the example that the pressure applied to the surface of the workpiece via the composite sheet can be controlled so as to be uniform over the entire workpiece.

Although an example of the embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to this. The embodiments are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

The pressing pressure control method for a composite sheet of the present invention is applicable to a mode in which a composite sheet containing a silicone rubber layer and a synthetic resin film layer is pressure-pressed onto the surface of a workpiece to process the workpiece, for example, an IC incorporated in an electric/electronic product. It can be applied to the processing of products in various industrial fields, such as passive components, semiconductors and other display/touch panel related product parts, LED lighting product parts and other electrical parts, vehicle parts, building materials, medical products, and daily necessities.

1 composite sheet, 11 silicone rubber layer, 12 synthetic resin film layer, 2 workpiece

Claims (5)

A method for controlling the pressure applied to the surface of a workpiece through the composite sheet when processing the workpiece by pressure-pressing a composite sheet including a silicone rubber layer and a synthetic resin film layer onto the surface of the workpiece, the method comprising:
Pressure control of the composite sheet in which the composite sheet is pressurized onto the surface of the workpiece using a composite sheet formed by varying the thickness of the silicone rubber layer according to the pressure distribution of the pressure applied to the workpiece during pressure pressing. Method. Corresponding to the pressure distribution applied to the workpiece when a composite sheet with a flat surface is pressure-pressed onto the workpiece surface, convex parts with a thick silicone rubber layer and pressure 2. The press pressure control method for a composite sheet according to claim 1, wherein the composite sheet is provided so that a concave portion of the silicone rubber layer with a small thickness is in contact with an area where the pressure is high. A composite sheet containing a silicone rubber layer and a synthetic resin film layer, which is used for processing the workpiece by pressurizing it onto the workpiece surface, and is formed by reducing the thickness of the silicone rubber layer in the plane in contact with the workpiece surface. A composite sheet having a structure in which at least one concave portion that is not open is provided around the composite sheet. 4. The composite sheet according to claim 3, wherein the concave portion is provided so as to be in contact with an area of the workpiece to which a large pressing pressure is applied when the composite sheet is pressure-pressed onto the surface of the workpiece. The composite sheet is a silicone rubber composite in which a silicone rubber layer made of silicone elastomer resin is formed on at least one side of a sheet or film mainly made of crystalline polyester resin, so that the sheet or film and the silicone rubber layer are integrated. The composite sheet according to claim 3 or 4.

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