Laminate, sealing material, and method for producing laminate

Abstract

To provide a laminate which can be manufactured by a simpler method and can be stuck with excellent strength, a seal material including the laminate, and a method for manufacturing the laminate.SOLUTION: The laminate includes a resin base material, a coating layer covering one surface of the resin base material, and a silicone foam layer laminated on the coating layer, in which the coating layer is formed of one or more selected from an acrylic resin, a urethane-based resin, a silicone-based resin, and a melamine-based resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate, a sealing material, and a method for manufacturing a laminate. [Background technology]

[0002] Silicone foams, which have excellent heat resistance, cold resistance, weather resistance, flame retardancy, cushioning properties, etc., have traditionally been used as sealing materials, heat insulating materials, vibration damping materials, etc. in electronic devices, electrical devices, automobiles, building materials, gas appliances, etc.

[0003] Known methods for fixing silicone foam to an adherend include attaching one side of double-sided tape to the silicone foam and then attaching the other side to the adherend, and also known is a method of applying an adhesive to the surface of the silicone foam to fix it to the adherend (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-326991 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, silicone foam does not have good adhesion to acrylic, urethane, or other adhesives. Therefore, to improve adhesion, the surface of the silicone foam may be subjected to a surface treatment such as plasma treatment or primer treatment, and then fixed to an adherend using double-sided tape, adhesive, or the like.

[0006] However, the above-mentioned method involves surface-treating the silicone foam and then laminating the adhesive, which increases the number of processing steps and makes the process complicated.

[0007] The problem that the present invention aims to solve is to provide a laminate that can be manufactured by a simpler method and can be attached with excellent strength, a sealing material that includes the laminate, and a method for manufacturing the laminate. [Means for solving the problem]

[0008] One aspect of the present invention is a laminate comprising a resin substrate, a coating layer covering one surface of the resin substrate, and a silicone foam layer laminated on the coating layer, wherein the coating layer is formed from one or more resins selected from the group consisting of acrylic resins, urethane resins, silicone resins, and melamine resins.

[0009] In the laminate of the above aspect, the thickness of the resin substrate is preferably 100 μm or less.

[0010] The laminate of the above aspect preferably further comprises a pressure-sensitive adhesive layer provided on the other surface of the resin substrate.

[0011] Another aspect of the present invention is a sealing material. The sealing material includes the laminate of the above aspect.

[0012] Another aspect of the present invention is a method for producing a laminate, comprising the steps of preparing a resin substrate having a coating layer on one side and a pressure-sensitive adhesive layer on the other side, applying a silicone foam-forming composition onto the coating layer, and foaming and curing the applied silicone foam-forming composition. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a laminate that can be manufactured by a simpler method and can be attached with excellent strength, a sealing material including the laminate, and a method for manufacturing the laminate. [Brief explanation of the drawings]

[0014] [Figure 1]FIG. 1 is a schematic cross-sectional view showing a laminate of the present embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing a test method for 180° peel strength. DETAILED DESCRIPTION OF THE INVENTION

[0015] The laminate according to this embodiment will be described in detail below.

[0016] The shape of the laminate of this embodiment can be any appropriate shape depending on the application.

[0017] In this specification, the density (apparent density) is the apparent density measured in accordance with JIS K7222:2005 "Foamed plastics and rubber - Determination of apparent density".

[0018] In this specification, hardness is the compressive stress when a φ50 mm sample is compressed by 25% at a rate of 1 mm / min in an environment of normal temperature and humidity, based on JIS K6254.

[0019] In this specification, the weight average molecular weight (number average molecular weight) can be measured by a known measurement method, for example, as a polystyrene-equivalent molecular weight using gel permeation chromatography (GPC).

[0020] 1.Laminate Fig. 1 is a schematic cross-sectional view showing a laminate of this embodiment. As shown in Fig. 1, the laminate 10 of this embodiment includes a resin substrate 13, a coating layer 12 covering one side of the resin substrate 13, and a silicone foam layer 11 laminated on the coating layer 12. An optional pressure-sensitive adhesive layer 14 is provided on the other side of the resin substrate 13. Furthermore, a separator 15 is provided on the surface of the pressure-sensitive adhesive layer 14 opposite the resin substrate 13.

[0021] In the laminate 10 of this embodiment, the silicone foam layer 11 is laminated on the resin substrate 13 via the coating layer 12. The coating layer 12 and the silicone foam layer 11 have excellent adhesion to each other, which can improve the peel strength of the silicone foam layer 11 with respect to the resin substrate 13.

[0022] The resin substrate 13, coating layer 12, silicone foam layer 11, adhesive layer 14, and separator 15 that constitute the laminate 10 will be described in detail below.

[0023] 1-1.Resin substrate 13 1-1-1.Material The material of the resin substrate 13 is not particularly limited, and known materials can be used. Examples include various materials such as polyesters such as polyethylene terephthalate (PET), polyolefins such as polyurethane, polyethylene (PE), and polypropylene (PP), and polyamides. In this embodiment, polyester is preferred as the resin substrate 13 from the viewpoints of strength, heat resistance, and adhesiveness of the adhesive. PET is more preferred.

[0024] 1-1-2.Shape The shape of the resin substrate 13 is not particularly limited as long as it is a shape that allows the raw material of the coating layer 12, which will be described later, to be applied (coated). For example, any shape such as a film or plate can be used.

[0025] 1-1-3. Thickness The thickness of the resin substrate 13 is preferably 1 μm or more, 3 μm or more, 5 μm or more, 7 μm or more, 10 μm or more, and is preferably 100 μm or less, 90 μm or less, 80 μm or less, 50 μm or less, etc. By setting the thickness of the resin substrate 13 within the above range, a laminate with excellent flexibility can be obtained, which makes it possible to attach the laminate to a curved adherend. Furthermore, the laminate can be firmly attached to the adherend via an adhesive or the like.

[0026] 1-2. Coating layer 12 As described above, the coating layer 12 covers one surface of the resin substrate 13. That is, the coating layer 12 is formed by applying (coating) the raw material of the coating layer 12 to one surface of the resin substrate 13 and drying it.

[0027] 1-2-1.Material The coating layer 12 is formed from one or more resins selected from an acrylic resin, a urethane resin, a silicone resin, and a melamine resin. Among these, the coating layer 12 is preferably formed from an acrylic resin, a urethane resin, or a melamine resin. By forming the coating layer 12 from the above-mentioned resin, adhesion to the silicone foam layer 11 can be further improved.

[0028] Acrylic resins refer to polymer resins obtained by addition polymerization of acrylic acid, methacrylic acid, and their derivatives (e.g., acrylamide, acrylonitrile, etc.) as monomers. Specific examples of acrylic resins include polyacrylic acid acrylic resins, polymethacrylic acid resins, and polymethyl methacrylate resins.

[0029] Urethane resins are polymeric compounds containing urethane bonds in the molecule, and are typically prepared by reacting polyols with isocyanates. Examples of polyols include polycarbonate polyols, polyether polyols, polyester polyols, and polyolefin polyols. These compounds may be used alone or in combination.

[0030] By silicone-based resin is meant a crosslinked, network-like polymer containing one or more silicon atoms (Si), in particular one or more SiO groups.

[0031] The melamine-based resin is a thermosetting resin obtained by polycondensing a condensate of melamine and aldehyde by heating, and examples thereof include methylated melamine resin, butylated melamine resin, and octylated melamine resin.

[0032] 1-2-2. Thickness The thickness of the coating layer 12 is preferably 0.5 μm or more, 0.6 μm or more, 0.7 μm or more, etc., and is preferably 10 μm or less, 9 μm or less, 8 μm or less, etc. By setting the thickness of the coating layer 12 within the above range, the adhesion to the silicone foam layer 11 can be further improved.

[0033] 1-3. Silicone foam layer 11 1-3-1.Material / Type The silicone resin forming the silicone foam layer 11 is a resin having organopolysiloxane as the main chain, and is not particularly limited.

[0034] The type of silicone foam layer 11 is not particularly limited, and examples thereof include solid raw material type silicone foam (such as millable silicone foam) and liquid raw material type silicone foam (such as two-component silicone foam).

[0035] Millable silicone foam is a silicone foam made from organopolysiloxane as the main raw material, which is mixed with various additives (fillers, dispersants, vulcanizing agents, etc.), kneaded, and then thermally cured. By using a blowing agent (chemical blowing agent) as an additive, it can be made into a foamed silicone resin.

[0036] Two-component silicone foam is a foam that forms bubbles (cells) when gas (hydrogen) is generated during hardening by mixing and stirring two liquid silicone materials.

[0037] Silicone foam layer 11 is preferably a two-component silicone foam.

[0038] 1-3-2.Thickness The thickness of the silicone foam layer 11 is not particularly limited, and is preferably, for example, 0.5 mm or more, 1.0 mm or more, 1.5 mm or more, 2.0 mm or more, and is preferably 20.0 mm or less, 15.0 mm or less, 10.0 mm or less, 5.0 mm or less.

[0039] 1-3-3. Density The density of the silicone foam layer 11 is not particularly limited, and is, for example, 100 kg / m 3 More than 125kg / m 3 More than 150kg / m 3 More than 175kg / m 3 More than 200kg / m 3 More than 900 kg / m 3 Below 800kg / m 3 Below 700kg / m 3 Below 600kg / m 3 Below 500kg / m 3 Below 400kg / m 3 Below 300kg / m 3 The following are preferred:

[0040] 1-3-4. Hardness (25% CLD) The hardness {25% CLD (kPa)} of the silicone foam layer 11 is preferably, for example, 1,000 kPa or less, 500 kPa or less, 300 kPa or less, 250 kPa or less, 200 kPa or less, 150 kPa or less, or 100 kPa or less.

[0041] The hardness {25% CLD (kPa)} of the silicone foam layer 11 can be adjusted by changing the material of the silicone foam, the cell diameter and density of the silicone foam, and the like.

[0042] 1-4. Adhesive layer 14 1-4-1.Material The material of the adhesive layer 14 is not particularly limited, and any known adhesive can be used, such as an acrylic adhesive, a urethane adhesive, a silicone adhesive, or a rubber adhesive, depending on the type of adherend, the application, the design requirements, and the like.

[0043] 1-4-2.Thickness The thickness of the adhesive layer 14 is not particularly limited and can be, for example, 1 μm or more and 100 μm or less, and can be selected depending on the type of adhesive, the application, design requirements, and the like.

[0044] 1-4-3. Structure The pressure-sensitive adhesive layer 14 may be in the form of a uniform film, a film having grooves or through holes, a dotted, fibrous, lattice, or other structure.

[0045] 1-5. Separator 15 When the laminate 10 includes a pressure-sensitive adhesive layer 14, a separator 15 may be further provided to protect the pressure-sensitive adhesive layer 14 until use. The material of the separator 15 and the release agent applied to the surface are not particularly limited, and known materials can be used. For example, the material of the separator 15 may be a resin film such as PET or PP, or paper. An example of the release agent is dimethylsiloxane.

[0046] The thickness of the separator 15 is not particularly limited, and can be, for example, 10 μm or more and 100 μm or less.

[0047] 2. Manufacturing method of laminate 10 The laminate 10 of this embodiment can be manufactured as follows: Here, an example will be described in which the silicone foam layer 11 is the two-component silicone foam described above.

[0048] The method for producing laminate 10 includes the steps of preparing resin substrate 13 having coating layer 12 on one side and pressure-sensitive adhesive layer 14 on the other side (preparation step), applying a silicone foam molding composition onto coating layer 12 (application step), and foaming and curing the applied silicone foam molding composition (foaming and curing step). Furthermore, the method for producing laminate 10 may include additional steps in addition to those described below.

[0049] This manufacturing method reduces the number of processing steps, such as surface treatment, compared to conventional methods in which a silicone foam layer is surface-treated and then an adhesive or the like is applied. This allows for a simpler manufacturing method and reduces costs. Each step is described in detail below.

[0050] 2-1. Preparation process In the preparation step, a resin substrate 13 is prepared which has a coating layer 12 on one side and a pressure-sensitive adhesive layer 14 on the other side. A separator 15 may be attached to the surface of the pressure-sensitive adhesive layer 14 opposite to the resin substrate 13. If the effects of the present invention can be achieved, a commercially available product (a resin substrate 13 having a coating layer 12 and / or a pressure-sensitive adhesive layer 14) may be used.

[0051] 2-2.Coating process In the application step, a silicone foam molding composition is prepared and applied onto coating layer 12. The silicone foam molding composition is obtained by mixing and stirring two-component liquid silicone in the presence of a catalyst such as a platinum catalyst. The silicone foam molding composition will be described in detail in "2-3. Foaming and curing step."

[0052] 2-3. Foaming and curing process In the foaming and curing step, the silicone foam molding composition is foamed (by the generated hydrogen gas) and cured by the following reaction, thereby obtaining a self-foaming reactive silicone foam.

[0053] Reaction 1: Reaction of a silanol-containing organopolysiloxane such as hydroxyl-terminated polydimethylsiloxane or a hydroxyl-containing compound (foaming aid) with an organohydrogenpolysiloxane such as methylhydrogenpolysiloxane having SiH groups at both ends and in the side chains. Reaction 2: Reaction of a vinyl-containing organopolysiloxane, such as dimethylpolysiloxane, whose both ends are blocked with dimethylvinylsiloxy groups, with an organohydrogenpolysiloxane, such as methylhydrogenpolysiloxane, which has SiH groups at both ends and in the side chains.

[0054] In addition, an inert gas such as air or nitrogen may be added when mixing and stirring the two-component liquid silicone raw materials. In this case, the inert gas acts as a foaming nucleus, allowing more uniform cells to be formed.

[0055] Specific examples of platinum catalysts include chloroplatinic acid, elemental platinum, chloroplatinic acid hexahydrate, complexes of chloroplatinic acid with sym-divinyltetramethyldisiloxane, dichloro-bis(triphenylphosphine)platinum(II), cis-dichlorobis(acetonitrile)platinum(II), dicarbonyldichloroplatinum(II), platinum chloride, platinum oxide, zero-valent platinum metal complexes such as Karstedt's catalyst, [Cp*Ru(MeCN)3]PF6, [PtCl2(cyclooctadiene)], solid platinum supported on a carrier (e.g., alumina, silica, or carbon black), platinum-vinylsiloxane complexes {e.g., Pt n (ViMe2SiOSiMe2Vi) c and Pt[(MeViSiO)4] d}, platinum-phosphine complexes {e.g., Pt(PPh3)4 and Pt(PBu3)4}, and platinum-phosphite complexes {e.g., Pt[P(OPh)3]4 and Pt[P(OBu)3]4}, where in the above formulae, "Me" represents methyl, "Bu" represents butyl, "Vi" represents vinyl, "Ph" represents phenyl, and c and d represent integers.

[0056] The hydroxyl group-containing compound (foaming aid) can be an alcohol such as benzyl alcohol or ethanol, or water. In this case, a stock solution containing the vinyl group-containing organopolysiloxane (main polymer), the hydroxyl group-containing compound (foaming aid), and the catalyst is prepared as Liquid A, and a stock solution containing the vinyl group-containing organopolysiloxane (main polymer) and the organohydrogenpolysiloxane (crosslinking agent) is prepared as Liquid B. Liquid A and Liquid B can be mixed and stirred to allow the foaming reaction and curing reaction to proceed.

[0057] The number average molecular weight of the main polymer is preferably 500 to 100,000, more preferably 1,000 to 70,000, and even more preferably 1,500 to 50,000. When two liquids consisting of liquid A and liquid B are used as described above, the mixing ratio (mass ratio) of liquid A to liquid B varies depending on the density and cell shape of the foam to be obtained, but is typically preferably 100:1 to 100:50.

[0058] The above-mentioned Liquid A may contain silica as a reinforcing material. The amount of silica added is not particularly limited and is greater than 0 to 40% by mass based on the total mass of Liquid A. Liquid A may also contain titanium oxide, aluminum hydroxide, calcium carbonate, etc. as a filler for adjusting viscosity and / or imparting functionality such as strength and flame retardancy. The total content of these fillers is not particularly limited and is greater than 0 to 50% by mass based on the total mass of Liquid A.

[0059] The reaction time for hydrogen generation is adjusted as appropriate depending on the density and cell shape of the foam to be obtained. It is usually 1 to 10 minutes, and preferably 2 to 6 minutes. The mixing temperature is adjusted as appropriate depending on the density and cell shape of the silicone foam layer 11 to be obtained. It is usually room temperature.

[0060] The density of silicone foam layer 11 can be adjusted by optimizing the temperature during hardening and foaming (molding), the amount of foaming aid, and the ratio of liquid A to liquid B (amount of Si-H added).

[0061] 3. Uses of the laminate 10 The laminate 10 according to this embodiment can be produced by a simpler method and can be attached with excellent strength, and therefore can be used as a gasket sealing material, heat insulating material, vibration-proof material, etc. in electronic devices, electrical devices, automobiles, building materials, gas appliances, etc. The sealing material of this embodiment includes the laminate 10 of the above aspect. Therefore, the sealing material can be produced by a simpler method and can be attached with excellent strength. [Example]

[0062] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0063] (Silicone foam raw material) Liquid A: Polyorganosiloxane with vinyl groups (contains platinum catalyst, etc.) (MOMENTIVE TSE571) (manufactured by Momentive Performance Materials Japan, LLC) Liquid B: Polyorganohydrogensiloxane with Si-H bonds (MOMENTIVE NI0539) (manufactured by Momentive Performance Materials Japan, LLC)

[0064] (Preparation of laminate) In each example and comparative example, the resin substrate shown in Table 1 was used. 65 g of liquid A and 5 g of liquid B were weighed out in a room temperature (25°C) environment. Liquid A was stirred at a rotation speed of 480 rpm for 30 seconds. Liquid B was added to the stirred liquid A, and further stirred at a rotation speed of 480 rpm for 20 seconds. The stirred mixture was poured onto the coating layer side of the resin substrate and molded. In this state, it was reacted in a drying oven at a heating temperature of 60°C for 3 minutes. It was then removed and further reacted in a curing oven at a heating temperature of 120°C for 4 minutes to obtain a laminate for each example and comparative example.

[0065] (Measurement / Evaluation) For each of the laminates of the Examples and Comparative Examples, the thickness, density, and hardness (25% CLD) of the silicone foam layer were measured.

[0066] The 180° peel strength (N / 24 mm) of each laminate of each Example and Comparative Example was measured. The peel strength test method is shown below. In addition, based on the state of the laminate after the peel strength test, the adhesion was evaluated according to the following evaluation criteria.

[0067] Peel strength test The laminates of each example and comparative example were cut into a 24 mm wide x 130 mm long piece. A lead-use PET film was attached to the edge of the resin substrate of the laminate using double-sided tape (not shown). Single-sided adhesive tape A (Teraoka Seisakusho Co., Ltd., No. 648#50) using a silicone-based adhesive was attached to the surface of the laminate opposite the resin substrate. Double-sided tape B (Nitto Denko Corporation, No. 5000NS) using an acrylic-based adhesive was then attached to the surface of single-sided adhesive tape A to prepare a test sample. The test sample was attached to a SUS plate, pressed back and forth twice with a 2 kg roller, and left at room temperature (23°C, 55% RH) for 24 hours. A 180° peel strength test was then performed using an autograph at room temperature (23°C, 55% RH) at a pulling rate of 200 mm / min (see Figure 2). Evaluation criteria A: Material fracture occurred in the silicone foam layer, and no interfacial peeling occurred between the silicone foam layer and the resin substrate. C: No material fracture occurred in the silicone foam layer, and interfacial peeling occurred between the silicone foam layer and the resin substrate.

[0068] The laminates of each Example and Comparative Example were aged at room temperature for one month, and then subjected to the peel strength test described above. Based on the state of the laminate after the peel strength test, the adhesion after aging at room temperature for one month was evaluated using the same evaluation criteria as above. Table 1 shows the measurement / evaluation results.

[0069] [Table 1] [Industrial Applicability]

[0070] The laminate of the present invention can be produced by a simpler method and can be attached with excellent strength, and therefore can be used as a gasket sealing material, heat insulating material, vibration-proof material, etc. in electronic devices, electrical devices, automobiles, building materials, gas appliances, etc.

Claims

1. The present invention comprises a resin substrate, a coating layer that covers one surface of the resin substrate, and a silicone foam layer that is laminated on the coating layer, The coating layer is formed from at least one resin selected from the group consisting of an acrylic resin, a urethane resin, a silicone resin, and a melamine resin.

2. The laminate according to claim 1 , wherein the resin substrate has a thickness of 100 μm or less.

3. The laminate according to claim 1 , further comprising a pressure-sensitive adhesive layer provided on the other surface of the resin substrate.

4. A sealing material comprising the laminate according to claim 1.

5. preparing a resin substrate having a coating layer on one side and a pressure-sensitive adhesive layer on the other side; applying a silicone foam molding composition onto the coating layer; and foaming and curing the applied silicone foam molding composition.

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