JP2014201014A - Multi-layered sheet - Google Patents

Abstract

The problem to be solved by the present invention is to provide a multilayer sheet in which the occurrence of warpage is suppressed. A multilayer sheet according to an embodiment includes a sheet-like composite material including a fluororesin and a heat-resistant woven fabric, or a core material made of a fluororesin sheet and having a bending resistance of 0.05 mN or more, And a silicone resin having a thickness of 10 to 150 μm provided on one side of the core material. [Selection] Figure 1

Description

  The present invention relates to a multilayer sheet.

  A multilayer sheet in which a fluororesin processed product and a different material of silicone rubber are laminated has been proposed. Such a multilayer sheet is manufactured by lamination using a continuous coating apparatus in consideration of manufacturing efficiency. For example, it is manufactured by coating a thermosetting silicone resin (knives, reverses, commas, slot dies, transfers, etc.) on a sheet-like fluororesin processed product, and then heating to cure.

  However, when a multilayer sheet in which such different materials are laminated receives heat in the manufacturing stage, warpage may occur due to a difference in thermal expansion generated in each material. When such a multi-layer sheet is used as a work sheet laid on a workbench, it will rise from the workbench due to the warpage that occurs, so it must be fixed with a weight, adhesive tape, etc., and workability is poor. .

  Therefore, there is a need for a multilayer sheet that provides stable workability without warping.

JP 2007-190802 A

  The problem to be solved by the present invention is to provide a multilayer sheet in which the occurrence of warpage is suppressed.

  The multilayer sheet according to the embodiment is composed of a sheet-like composite material including a fluororesin and a heat-resistant woven fabric, or a fluororesin sheet, a core material having a bending resistance of 0.05 mN or more, and the core material And a silicone resin having a thickness of 10 to 150 μm provided on one side.

  According to the embodiment, a multilayer sheet in which the occurrence of warpage is suppressed is provided.

FIG. 1 is a cross-sectional view of a multilayer sheet according to an embodiment. FIG. 2 is a cross-sectional view of the multilayer sheet according to the embodiment when a composite material is used as the core material. Drawing 3 is a sectional view for explaining the measuring method of the amount of curvature of the multilayer sheet concerning an embodiment. FIG. 4 is a graph showing the relationship between the amount of warpage and the bending resistance of the core material in various multilayer sheets.

  Hereinafter, a multilayer sheet according to an embodiment will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a multilayer sheet according to an embodiment. As illustrated, the multilayer sheet 10 according to the embodiment includes a sheet-like core material 1 and a silicone resin 2 provided on one surface thereof.

  The core material 1 has a bending resistance of 0.05 mN or more. This bending resistance is measured based on the Gurley bending resistance test (JIS L 1096). The bending resistance of the core material 1 is preferably 0.35 mN or more.

  The thickness of the core material 1 is, for example, 50 to 250 μm.

  The core material 1 is made of a sheet-like composite material including a fluororesin and a heat-resistant woven fabric. Or the core material 1 consists of a fluorine resin sheet.

  The composite material is obtained, for example, by impregnating a heat-resistant woven fabric with a fluororesin fine particle aqueous dispersion, followed by drying, firing and the like. In FIG. 2, sectional drawing of the multilayer sheet 10 at the time of using the composite material 4 as a core material is shown. The composite material 4 is composed of a heat-resistant woven fabric composed of warp yarns 5 and weft yarns 6 and a fluorine resin 7 filling the periphery of the fabric. The heat-resistant woven fabric is a woven fabric made of fibers that can withstand the firing temperature of the fluorine resin, and is made of, for example, at least one fiber selected from the group consisting of glass, aramid resin, carbon, and stainless steel. The composite material is obtained by impregnating a glass cloth with a fluororesin dispersion obtained by stabilizing an emulsion-polymerized aqueous dispersion with a surfactant, drying the glass cloth, and firing the glass cloth. It may be. The firing temperature at this time is, for example, 350 to 420 ° C.

  The fluororesin sheet means a sheet made of fluororesin. For example, a fluororesin sheet can be obtained by cutting a molded body of fluororesin. Specifically, the fluororesin molding powder obtained by suspension polymerization is compression-molded into a cylindrical shape, fired, and then cut. The compression molding pressure at this time is, for example, 50 MPa, and the firing temperature is, for example, 350 to 420 ° C.

  Examples of the fluororesin contained in the core material include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and tetrafluoroethylene. Ethylene-ethylene copolymer resin (ETFE) or vinylidene fluoride resin (PVDF).

  The thickness of the silicone resin 2 is 10 to 150 μm.

  The silicone resin 2 is selected to provide a sufficient grip force when the multilayer sheet is laid on the work table.

  The bonding strength between the silicone resin 2 and the core material can be improved by subjecting the core material to a surface treatment. For example, after one surface of the core material is activated by the inorganic particle adhesion baking treatment, a silicone resin material can be applied to the one surface and heat-cured.

Moreover, you may utilize the strong reducing power of metal Na by the THF solution of Na / naphthalene complex, or ether as this surface treatment. In this case, due to the reducing power, F atoms are extracted from —CF ₂ — on the surface of the fluororesin to generate carbon radicals, and these carbon radicals react with H ₂ O and O ₂ in the atmosphere to produce C—H , C—OH, C═O and other functional groups are formed. As a result, the surface free energy of the fluororesin is increased, and a silicone resin material can be applied to the surface and subjected to a thermosetting treatment.

  Examples of silicone resin materials include polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule, polyorganosiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, addition reaction Thermosetting liquid silicone rubber containing a platinum catalyst and surface-treated powdered silica.

  According to the embodiment, a multilayer sheet in which the occurrence of warpage is suppressed is provided. Since the occurrence of warpage is suppressed, when placed on a flat surface such as a work table, the sheet does not partially float and adheres to the surface. Therefore, high workability is achieved.

  Moreover, since the thickness of the silicone resin is 10 to 150 μm in the multilayer sheet according to the embodiment, the manufacturing cost can be suppressed while achieving a sufficient grip force with respect to the work table. When it is less than 10 μm, the grip force is insufficient, and when it exceeds 150 μm, the grip force is sufficient, but the manufacturing cost increases.

  Moreover, since the multilayer sheet which concerns on embodiment uses the fluororesin as material, it is excellent in heat resistance and non-adhesiveness.

  Another embodiment is a work sheet. The working sheet may be obtained by cutting the above-described multilayer sheet as necessary.

  The work sheet can be used, for example, for kneading work of an adhesive body such as bread dough using its non-adhesive property. Further, the working sheet can be used as a sheet when mixing chemicals or the like by utilizing its chemical resistance characteristics. The working sheet can also be used to handle delicate or elaborate products using its softness. Further, the work sheet can be used as a white board by writing on the surface of the core material with a marker using the non-adhesive property. Moreover, the work sheet can be used as a mouse pad or as a seismic isolation sheet for preventing furniture from falling due to its sliding characteristics.

  Various multilayer sheets were produced, and their warpage amount and grip force were measured.

(Production method)
After laminating a silicone resin material on one side of the core material, it was heated for 5 minutes at a temperature of 180 ° C. using an oven to produce 20 types of multilayer sheets. Examples of the silicone resin material include polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule, polyorganosiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, and addition reaction type A thermosetting liquid silicone rubber containing a platinum catalyst and surface-treated powder silica was used.

  As the core material, a composite material or a fluorine resin sheet was used. The composite material is obtained by impregnating a glass cloth with a fluororesin dispersion obtained by stabilizing an emulsion-polymerized aqueous dispersion with a surfactant, drying the glass cloth, and firing at 350 to 420 ° C. It was. The fluororesin sheet was obtained by compressing and molding a fluororesin molding powder obtained by suspension polymerization into a cylindrical shape at 50 MPa, firing at 350 to 420 ° C., and then cutting.

  The types of core materials used, the mass per fixed area, the thickness and the bending resistance, and the thickness of the laminated silicone resin are summarized in Table 1 below. The bending resistance of the core material was measured based on the Gurley bending resistance test (JIS L 1096). Further, the thickness of the silicone resin was calculated by subtracting only the thickness of the core material from the total thickness of the core material and the silicone resin in accordance with ISO 2286-3.

(Measuring method)
The amount of warpage of the produced multilayer sheet was measured based on a polymeric tension floor test method (JIS A 1454). That is, a test piece of 100 mm × 100 mm was prepared and allowed to stand for 12 hours, and then the amount of warpage was measured. FIG. 3 is a cross-sectional view for explaining a method for measuring the amount of warpage of a multilayer sheet. As shown in this figure, the core material 1 side was placed in contact with the installation surface 3, and the distance l between the installation surface 3 and the end of the core material was taken as the amount of warpage. The warp amount was the largest of the four side warp amounts.

  Moreover, the grip force of the produced multilayer sheet was measured. As the grip force, the multilayer sheet was placed on the float glass so that the silicone resin was in contact with the glass surface, and whether or not there was a shift when a force was applied in the shear direction from the core material side was determined.

The measured warpage amount and grip force are shown in Table 1 below.

  FIG. 4 is a graph showing the relationship between the measured amount of warpage and the bending resistance. In this graph, Examples 1 to 18 were plotted based on the results in Table 1, with the horizontal axis representing the bending resistance and the vertical axis representing the amount of warpage. Furthermore, the points of the example in which the kind of the core material used and the thickness of the silicone resin are common are connected by a line and divided into six series. For example, in the series 1 “composite a + 50 μm thick silicone resin”, points of Examples 1, 4 and 7 are connected.

  From the results of series 2, 3, 5 and 6 in FIG. 4, it can be seen that the amount of warpage decreases as the bending resistance increases. Furthermore, it can be seen from the comparison of series 1 to 3 and the comparison of series 4 to 6 that the amount of warpage decreases as the thickness of the silicone resin decreases. In particular, in series 1 and 4 in which the thickness of the silicone resin was 50 μm, the warpage amount was 0 at all points regardless of the bending strength of the core material.

  Moreover, it can be seen from the results of Example 20 in Table 1 that the grip strength is insufficient when the thickness of the silicone resin is less than 10 μm.

  DESCRIPTION OF SYMBOLS 1 ... Core material, 2 ... Silicone resin, 3 ... Installation surface, 4 ... Composite material, 5 ... Warp, 6 ... Weft, 7 ... Fluororesin, 10 ... Multi-layer sheet.

Claims (6)

A sheet-like composite material including a fluororesin and a heat-resistant woven fabric, or a core material composed of a fluororesin sheet and having a bending resistance of 0.05 mN or more;
A multilayer sheet comprising a silicone resin having a thickness of 10 to 150 μm provided on one side of the core material.   2. The multilayer sheet according to claim 1, wherein one side of the core material is activated by an inorganic particle adhesion firing process, and then the silicone resin material is applied to the one side and heat-treated.   The silicone resin material is a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule, a polyorganosiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, an addition reaction type The multilayer sheet according to claim 2, which is a thermosetting liquid silicone rubber containing a platinum catalyst and surface-treated powder silica.   The multilayer sheet according to claim 1, wherein the heat-resistant woven fabric comprises at least one fiber selected from the group consisting of glass, aramid resin, carbon, and stainless steel.   The composite material is obtained by impregnating a glass cloth with a fluororesin dispersion obtained by stabilizing an emulsion-polymerized aqueous dispersion with a surfactant, drying the glass cloth, and then firing the glass cloth. 4. The multilayer sheet according to any one of items 1 to 3.   The composite sheet according to any one of claims 1 to 3, wherein the fluororesin sheet is obtained by compressing and molding a fluororesin molding powder obtained by suspension polymerization into a cylindrical shape, followed by firing. Layer sheet.

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