JP2011162717A - Foaming seal material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foaming seal material which is excellent in the absorptiveness of the shock due to fall and in the dynamic dust-proofness. <P>SOLUTION: The foaming seal material is provided on at least one side of a foamed structural body with a pressure-sensitive adhesive layer having a polyoxyalkylene-based polymer as a principal component. Preferably, the pressure-sensitive adhesive layer is formed with a pressure-sensitive adhesive composition containing the following components (A) to (C): (A) is a polyoxyalkylene-based polymer having in one molecule at least one alkenyl group, (B) is a compound having in one molecule two or more hydrosilyl groups, and (C) is a hydrosilylation catalyst. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a foam sealing material. More specifically, the present invention relates to a foam sealing material used as a fixed sealing material for electric / electronic devices (cell phones, portable terminals, digital cameras, video movies, personal computers, other home appliances, etc.).

  In electrical / electronic devices (cell phones, portable terminals, digital cameras, video movies, personal computers, other household appliances, etc.), they are fixed to image display devices (displays) such as liquid crystal displays (LCD), electroluminescence displays, plasma displays, etc. When fixing an image display member or an optical member such as a camera or lens to a predetermined part (fixed part, etc.), a foam material [a pressure sensitive adhesive layer is laminated on at least one side of a foam structure (foam)) Laminates, foamed sealing materials] are used.

  Examples of the form of use of the foam material include a shock absorber (gasket) (a shock absorber for a mobile phone) around a display (for example, LCD) of a mobile phone. For example, a shock absorber for a mobile phone has a sheet thickness of about 1 mm, is punched into a frame shape with a width of 1 to 2 mm, is fixed to a container (housing, case) side with double-sided tape, and is compressed by about 30 to 50%. And used.

  In such a usage pattern, the foam material is not only used as a shock absorbing material for protecting the display from being damaged when the mobile phone is dropped, but also to a display unit (for example, an LCD unit). A dustproof property and an airtight function for preventing intrusion of dust are also required (see Patent Document 1).

  However, when receiving a large impact, such as when a mobile phone is dropped, the impact absorption and the dust resistance during impact (hereinafter sometimes referred to as “dynamic dust resistance”) are contradictory requirements. It was difficult to maintain dynamic dust resistance while having shock absorption. In other words, in order to prevent cracks in the display, considering the shock absorption in the foam material, a soft material is used as the foam material to reduce the stress generated between the display and the foam material, resulting in deformation of the foam material. It is necessary to relax the compressive load. Therefore, the shock absorbing performance requires the stress relaxation property of the foam material, but a material having a good relaxation performance tends to slow the strain recovery property after deformation. If the foam material has a slow strain recovery capability, the deformation of the foam material cannot follow the deformation of the display, and a gap will be formed between the foam material and the display. Will invade. As a result, foreign matter is present on the screen display of the display, resulting in disturbance. That is, as a result, foreign matter may be present on the display, and the visibility of the display may be reduced.

  For this reason, foam materials around the display of a mobile phone (frame shape foam material of a mobile phone, window frame-shaped foam material of a mobile phone) are required to have a shock absorption property and dynamic dustproof property when dropped.

JP 2005-97566 A

  As described above, the impact absorption and dynamic dust resistance at the time of dropping are in a trade-off relationship for the foam material. For example, when the stress relaxation property is improved, the strain recovery property tends to deteriorate. If the distortion recovery property of the foam material is poor, the deformation of the foam material cannot follow the recovery of the deformation of the display or the container (housing, case), and a gap is generated between the foam material and the display.

  Therefore, in order to prevent a gap between the foam material and the display at the time of impact, the present inventor (1) affixed between the foam material and the display with a double-sided tape, and the deformation of the foam material is displayed at the time of the drop impact Measures such as following the deformation of the display and (2) inserting an appropriate adhesive material (joining material) between the foam material and the display, and allowing the display material to follow the deformation during a drop impact by deformation of the adhesive material. investigated. Note that “double-sided tape” means “double-sided adhesive tape or sheet” and includes “double-sided tape” and “double-sided sheet”.

  The difference between the above (1) and the above (2) is that in the case of (1), deformation of the material to be used such as double-sided tape is not expected, and the compressed foam material is adhered when the deformation of the display is recovered. It is a method to follow with force. Since the recovery speed of the display at the time of dropping is high, peeling of the double-sided tape from the display interface or the container surface (housing surface, case surface) or destruction of the foam material may occur. Further, when the adhesive strength of the double-sided tape is increased, it is expected that the workability of the bonding of the foam material is lowered and the reworkability at the time of bonding becomes difficult.

  In the method (2), since the recovery speed of the display at the time of dropping is high, an instantaneous stress concentration can be considered at the interface between the foam material and the adhesive material. Therefore, this is a method of imparting viscoelasticity to the joining material used between the foam material and the display so as to be accompanied by elongation deformation when recovering the strain after impact in order to reduce stress concentration.

  In the case of an acrylic pressure-sensitive adhesive generally used, it corresponds to the above (1), is poor in stress relaxation, and cannot be expected to have an effect of improving impact absorption. Furthermore, although high adhesive force can be obtained, the reworkability may be inferior.

  In the case of a rubber-based pressure-sensitive adhesive, it corresponds to the above (2), and the impact absorption can be enhanced by viscoelasticity, but the adhesive strength is weak, and it is dustproof by rework by peeling from the foam or adherend. There was a risk of lowering.

  Accordingly, an object of the present invention is to provide a foamed sealing material that is excellent in shock absorption and dynamic dustproofness due to dropping.

  As a result of intensive studies to solve the above problems, the present inventor has provided a pressure-sensitive adhesive layer mainly composed of a polyoxyalkylene polymer on at least one side of the foam structure in the foam seal material. As a result of the construction, the present inventors have found that a foamed sealing material excellent in both properties of impact absorption at the time of dropping and dynamic dustproof property can be obtained, and the present invention has been completed.

  That is, the present invention provides a foamed sealing material characterized in that an adhesive layer mainly composed of a polyoxyalkylene polymer is provided on at least one side of a foamed structure.

Furthermore, the said adhesive layer provides the said foaming sealing material currently formed with the adhesive composition containing the component of the following (A)-(C).
(A): polyoxyalkylene polymer having at least one alkenyl group in one molecule (B): compound having two or more hydrosilyl groups in one molecule (C): hydrosilylation catalyst

  Furthermore, the foamed sealing material is provided, wherein an adhesive intermediate layer is provided between the foam structure and the pressure-sensitive adhesive layer containing a polyoxyalkylene polymer as a main component.

  Furthermore, the foamed sealing material is formed through the step of reducing the pressure after impregnating a resin composition containing a thermoplastic polymer with a high-pressure inert gas.

  Furthermore, the foamed seal is formed by a process in which the foamed structure is decompressed after impregnating a non-foamed resin molded article made of a resin composition containing a thermoplastic polymer with a high-pressure inert gas. Providing materials.

  Furthermore, the said foaming structure provides the said foaming sealing material formed by further heating after pressure reduction.

  Furthermore, the said foaming sealing material whose said inert gas is a carbon dioxide is provided.

  Furthermore, the foamed sealing material is provided in which the inert gas is in a supercritical state.

  Furthermore, the said foaming sealing material used for sealing around a display is provided.

  Since the foamed sealing material of the present invention has the above-described configuration, it is excellent with respect to both characteristics of impact absorption at the time of dropping and dynamic dust resistance.

It is the schematic showing the sample for evaluation used when evaluating dynamic dustproofness. It is a cut part end view of the evaluation container for dynamic dustproof evaluation which equipped with the sample for evaluation. It is a top view of the evaluation container for dynamic dustproof evaluation equipped with the sample for evaluation. It is a graph which shows the measurement result of the peeling strength by a micro servo apparatus.

  The foamed sealing material (foam material) of the present invention has a structure in which an adhesive layer mainly composed of a polyoxyalkylene polymer is provided on at least one side of a foamed structure (foam). Thus, the foamed sealing material of the present invention is a laminate having a structure in which the pressure-sensitive adhesive layer is laminated directly or via another layer on at least one surface side of the foam.

(Foam structure)
The foam structure in the foam sealing material of the present invention is a foam having a cell structure (foam structure). As the foam structure constituting the foam sealing material of the present invention, a resin foam obtained by foaming and molding a resin composition is suitably used. Since the foamed sealing material of the present invention has a foamed structure (particularly a resin foam), the foamed structure inherently has characteristics such as shock absorption, step following ability, dustproofness, flexibility, sealing properties, and soundproofing. Excellent.

  In addition, the said resin composition is a composition which forms a resin foam, and is a composition which contains at least the following thermoplastic polymer. Moreover, the resin composition may contain an additive as necessary. Examples of the resin composition include a composition containing at least a mixture of a polyolefin resin such as polypropylene and an olefin elastomer such as an ethylene-propylene copolymer.

  The cell structure of the foam structure (particularly the resin foam) is not particularly limited, but is a closed cell structure, a semi-continuous semi-closed cell structure (a cell structure in which a closed cell structure and an open cell structure are mixed, The ratio is not particularly limited), and a cell structure in which the closed cell structure part is 40% or less, preferably 30% or less from the viewpoint of flexibility in the cell structure of the resin foam is particularly suitable. The cell structure can be controlled, for example, by adjusting the expansion ratio according to the amount of gas to be impregnated and the pressure during the production of the resin foam described later.

  The average cell diameter of the foam structure (particularly resin foam) is not particularly limited, but is preferably 10 to 180 μm, more preferably 20 to 150 μm, from the viewpoint of impact absorption and dynamic dust resistance when dropped. Even more preferably, it is 30 to 120 μm.

  In addition, said average bubble diameter (average cell diameter) captures the enlarged image of a bubble structure part with a digital microscope (brand name "VH-8000" Keyence Corporation make), and image analysis software (brand name "Win ROOF"). It is calculated | required by analyzing an image using Mitani Corporation.

  The thermoplastic polymer (thermoplastic resin) that is the material of the resin foam is not particularly limited as long as it is a polymer exhibiting thermoplasticity and can be foamed. Examples of such thermoplastic polymers include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, a copolymer of ethylene and propylene, ethylene or propylene and other α-olefins (for example, , Butene-1, pentene-1, hexene-1, 4-methylpentene-1, etc.), ethylene and other ethylenically unsaturated monomers (for example, vinyl acetate, acrylic acid, acrylic ester) , Methacrylic acid, methacrylic acid ester, vinyl alcohol, etc.) and other polyolefin resins; polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin) and other styrene resins; 6-nylon, 66-nylon Polyamide resins such as 12-nylon; poly Polyimide; Polyetherimide; Acrylic resin such as polymethyl methacrylate; Polyvinyl chloride; Polyvinyl fluoride; Alkenyl aromatic resin; Polyester resin such as polyethylene terephthalate and polybutylene terephthalate; Bisphenol A polycarbonate Polycarbonate; polyacetal; polyphenylene sulfide and the like. In addition, when a thermoplastic polymer is a copolymer, the copolymer of any form of a random copolymer and a block copolymer may be sufficient.

  As the thermoplastic polymer, a polyolefin-based resin can be suitably used. As the polyolefin-based resin, it is preferable to use a resin having a broad molecular weight distribution and having a shoulder on the high molecular weight side, a slightly cross-linked resin (a slightly cross-linked resin), a long-chain branched resin, or the like.

  The thermoplastic polymer also includes rubber components and thermoplastic elastomers that exhibit rubber properties at room temperature and thermoplastic at high temperatures. Since the rubber component and the thermoplastic elastomer have a glass transition temperature of room temperature or lower (for example, 20 ° C. or lower), for example, in a foamed sealing material, flexibility and shape followability can be remarkably improved.

  The rubber component and the thermoplastic elastomer are not particularly limited as long as they have rubber elasticity and can be foamed. For example, natural or synthetic such as natural rubber, polyisobutylene, polyisoprene, chloroprene rubber, butyl rubber, and nitrile butyl rubber. Rubber; Ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, polybutene, olefinic elastomer such as chlorinated polyethylene; styrene-butadiene-styrene copolymer, styrene-isoprene- Styrene elastomers such as styrene copolymers and hydrogenated products thereof; polyester elastomers; polyamide elastomers; and various thermoplastic elastomers such as polyurethane elastomers. In the present application, “rubber component and thermoplastic elastomer” may be simply referred to as “thermoplastic elastomer”.

  In the resin composition, the thermoplastic polymer is used alone or in combination of two or more. In the resin composition, any of thermoplastic elastomers, thermoplastic polymers other than thermoplastic elastomers, thermoplastic elastomers, and mixtures of thermoplastic polymers other than thermoplastic elastomers may be used as the thermoplastic polymer.

  Examples of the thermoplastic polymer as a mixture of the thermoplastic elastomer and the thermoplastic polymer other than the thermoplastic elastomer include a mixture of an olefin elastomer such as an ethylene-propylene copolymer and an olefin polymer such as polypropylene. Can be mentioned.

  When a mixture of a thermoplastic elastomer and a thermoplastic polymer other than the thermoplastic elastomer is used as the thermoplastic polymer, the mixing ratio (% by weight) is the former / the latter = 1/99 to 99/1 (preferably 10/90). To 90/10, more preferably 20/80 to 80/20). When the ratio of the thermoplastic elastomer is less than 1% by weight, the cushioning property of the resin foam tends to be lowered. On the other hand, when it exceeds 99% by weight, gas is easily released during foaming, and a highly foamed resin foam. Getting a body becomes difficult.

  The resin foam may further contain powder particles. The powder particles exhibit a function as a foam nucleating agent during foam molding. Therefore, the resin foam of a favorable foaming state can be obtained by mix | blending powder particle. Examples of powder particles include powdered talc, silica, alumina, zeolite, calcium carbonate, magnesium carbonate, barium sulfate, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, mica, montmorillonite, etc., carbon particles Glass fiber, carbon tube, etc. can be used. The powder particles can be used alone or in combination of two or more.

  In the resin foam, powder particles having an average particle diameter (particle diameter) of about 0.1 to 20 μm can be suitably used as the powder particles. If the average particle size of the powder particles is less than 0.1 μm, it may not function sufficiently as a nucleating agent, and if the particle size exceeds 20 μm, it may cause gas loss during foam molding.

  Although it does not restrict | limit especially as a compounding quantity of a powder particle, For example, 0.1-150 weight part (preferably 1-130 weight part, More preferably, 2-120 weight part) with respect to 100 weight part of thermoplastic polymers. It can be suitably selected from the range. When the blending amount of the powder particles is less than 0.1 parts by weight, it becomes difficult to obtain a uniform foam. On the other hand, when the amount exceeds 150 parts by weight, the viscosity as the resin composition is remarkably increased and foaming is performed. Gas formation may occur during formation, which may impair foaming characteristics.

  Moreover, since the resin foam is comprised with the thermoplastic polymer, it has the characteristic of being easy to burn. Therefore, when using the foamed sealing material in which the resin foam of the present invention is used for an application indispensable to impart flame retardancy such as electrical / electronic equipment, it has flame retardancy as powder particles. It is preferable that powder particles (for example, various powdery flame retardants) are blended. In addition, a flame retardant can be used with powder particles other than a flame retardant.

  In the present invention, an inorganic flame retardant is suitable as the flame retardant in the powdery flame retardant. As the inorganic flame retardant, for example, a brominated flame retardant, a chlorinated flame retardant, a phosphorus flame retardant, an antimony flame retardant, etc. may be used. It produces gas components that are harmful and corrosive to equipment. Phosphorus flame retardants and antimony flame retardants have problems such as toxicity and explosive properties. A flame retardant can be suitably used. Examples of the non-halogen-nonantimony inorganic flame retardant include hydrated metal compounds such as aluminum hydroxide, magnesium hydroxide, magnesium oxide / nickel oxide hydrate, magnesium oxide / zinc oxide hydrate, and the like. . The hydrated metal oxide may be surface treated. In addition, a flame retardant is used individually or in combination of 2 or more types.

  When the flame retardant is used, the amount of the flame retardant used is not particularly limited, and is appropriately selected from the range of 5 to 130 parts by weight (preferably 10 to 120 parts by weight) with respect to 100 parts by weight of the thermoplastic polymer. can do. If the amount of the flame retardant used is too small, the flame retardant effect is reduced. Conversely, if the amount is too large, it is difficult to obtain a highly foamed foam.

  In the present invention, the resin composition forming the resin foam may contain a lubricant. The lubricant has the effect of improving the fluidity of the thermoplastic polymer and suppressing the thermal deterioration of the thermoplastic polymer. Such a lubricant is not particularly limited as long as it has an effect on improving the fluidity of the thermoplastic polymer. For example, hydrocarbon lubricants such as liquid paraffin, paraffin wax, microwax and polyethylene wax; stearic acid Fatty acid lubricants such as behenic acid and 12-hydroxystearic acid; and ester lubricants such as butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, hydrogenated castor oil, stearyl stearate, and the like. In addition, a lubricant is used individually or in combination of 2 or more types.

  The addition amount of the lubricant is, for example, 0.5 to 10 parts by weight (preferably 0.8 to 8 parts by weight, more preferably 1 to 6 parts by weight) with respect to 100 parts by weight of the thermoplastic polymer. When the addition amount exceeds 10 parts by weight, the fluidity becomes too high and the expansion ratio may be lowered. On the other hand, if it is less than 0.5 parts by weight, the fluidity cannot be improved, the stretchability at the time of foaming is lowered, and the foaming ratio may be lowered.

  Furthermore, in this invention, the shrinkage inhibitor may be contained in the resin composition which forms a resin foam. The shrinkage-preventing agent has a function of effectively suppressing permeation of a foaming agent gas (particularly, an inert gas described later) by forming a molecular film on the surface of the bubble (cell) film of the resin foam. Such a shrinkage-preventing agent is not particularly limited as long as it has an effect of suppressing the permeation of bubbles. For example, fatty acid metal salts (for example, fatty acid such as stearic acid, behenic acid, 12-hydroxystearic acid) A salt of aluminum, calcium, magnesium, lithium, barium, zinc, lead, etc.); fatty acid amide [fatty acid amide (monoamide or bisamide) having about 12 to 38 carbon atoms (preferably about 12 to 22 carbon atoms) Bisamide is preferably used to obtain a fine cell structure.), For example, stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, lauric acid bisamide, etc. ] Etc. are mentioned. In addition, an anti-shrink agent is used individually or in combination of 2 or more types.

  The addition amount of the shrinkage inhibitor is, for example, 0.5 to 10 parts by weight (preferably 0.7 to 8 parts by weight, more preferably 1 to 6 parts by weight) with respect to 100 parts by weight of the thermoplastic polymer. . If the addition amount exceeds 10 parts by weight, gas efficiency is lowered in the cell growth process, so that a cell having a small cell diameter can be obtained, but there are also many unfoamed portions, which may reduce the foaming ratio. On the other hand, if the amount is less than 0.5 part by weight, the coating film is not sufficiently formed, and gas escape occurs at the time of foaming, causing shrinkage and reducing the foaming ratio.

  The additive is not particularly limited, and for example, the lubricant and the shrinkage inhibitor may be used in combination. For example, a lubricant such as stearic acid monoglyceride and a shrinkage preventing agent such as erucic acid amide or lauric acid bisamide may be used in combination.

  In addition to the above, the additive added as necessary is not particularly limited. For example, crystal nucleating agent, plasticizer, colorant (pigment, dye, etc.), ultraviolet absorber, antioxidant, anti-aging Agents, fillers, reinforcing agents, antistatic agents, surfactants, tension modifiers, fluidity modifiers, clays, vulcanizing agents, surface treatment agents, various forms of flame retardants other than powders, etc. . The addition amount of the additive can be appropriately selected within a range that does not impair the formation of bubbles and the like, and the addition amount used in normal resin molding can be adopted.

  The resin composition can be obtained, for example, by mixing the thermoplastic polymer with an additive that is added as necessary.

  The foaming method used when foaming and molding the resin composition to obtain a resin foam is not particularly limited, and examples thereof include commonly used methods such as a physical method and a chemical method. A general physical method is a method in which a low boiling point liquid (foaming agent) such as chlorofluorocarbons or hydrocarbons is dispersed in a thermoplastic polymer, and then heated to volatilize the foaming agent to form bubbles. . In addition, a general chemical method is a method in which bubbles are formed by a gas generated by thermal decomposition of a compound (foaming agent) added to a thermoplastic polymer. However, general physical methods are concerned about flammability and toxicity of substances used as foaming agents, and environmental effects such as ozone layer destruction. In addition, in general chemical methods, the residue of foaming gas does not remain in the foam. Therefore, contamination with corrosive gas or impurities in the gas is a problem, especially in electronic equipment applications where low pollution requirements are high. Become. Moreover, in any of these physical methods and chemical methods, it is difficult to form a fine bubble structure, and it is particularly difficult to form a fine bubble of 300 μm or less.

  For this reason, as a foaming method used when a resin composition is foamed and molded to obtain a resin foam, a foam having a small cell diameter and a high cell density can be easily obtained. A method using a high-pressure gas is preferable, and a method using a high-pressure inert gas as a foaming agent is particularly preferable. In addition, an inert gas means the gas inert with respect to the thermoplastic polymer in a resin composition. That is, the cell structure of the resin foam constituting the sealing material of the present invention is particularly preferably formed by a method using a high-pressure inert gas as a foaming agent.

  As a method of obtaining a resin foam by foaming and molding a resin composition by a method using a high-pressure gas as a foaming agent, specifically, a high-pressure gas is applied to the resin composition (resin composition containing a thermoplastic polymer). After impregnating with, a method of forming through a step of reducing pressure, after impregnating a high-pressure gas into an unfoamed resin molded article made of a resin composition (resin composition containing a thermoplastic polymer), and then through a step of reducing pressure A method of forming, or impregnating a molten resin composition (a resin composition containing a molten thermoplastic polymer) with a gas (for example, an inert gas) under a pressurized state, and then subjecting it to molding with reduced pressure. A suitable method is a method formed by the above method. That is, it is preferable that the cellular structure (foamed structure) of the resin foam is formed through a step of reducing pressure after impregnating with a high-pressure gas.

  The inert gas is not particularly limited as long as it is inert with respect to the thermoplastic polymer and can be impregnated, and examples thereof include carbon dioxide, nitrogen gas, and air. These gases may be mixed and used. Among these, carbon dioxide can be suitably used because the amount of impregnation into the thermoplastic polymer used as the material of the resin foam is large and the impregnation speed is high.

  Furthermore, from the viewpoint of increasing the impregnation rate into the resin composition, the high-pressure gas (particularly inert gas, and further carbon dioxide) is preferably in a supercritical state. In the supercritical state, the solubility of the gas in the thermoplastic polymer is increased, and a high concentration can be mixed. In addition, when the pressure drops suddenly after impregnation, since it is possible to impregnate at a high concentration as described above, the generation of bubble nuclei increases, and the density of bubbles formed by the growth of the bubble nuclei has a porosity. Even if they are the same, they become larger, so that fine bubbles can be obtained. Carbon dioxide has a critical temperature of 31 ° C. and a critical pressure of 7.4 MPa.

  When a resin foam is produced by impregnating a resin composition with a high-pressure gas, the resin composition is pre-molded into an appropriate shape such as a sheet, for example, to obtain an unfoamed resin molded product (not yet formed). (Foamed resin molded body), this unfoamed resin molded product may be impregnated with a high-pressure gas and foamed by releasing the pressure, and the resin composition may be pressurized under a high-pressure gas. In addition, it may be kneaded and molded at the same time as the pressure is released, and the molding and foaming may be performed simultaneously. In this way, a pre-molded unfoamed resin molded product may be impregnated with a high-pressure gas, or a molten resin composition is impregnated with a high-pressure gas under pressure and then molded during decompression. You may attach to.

  That is, the resin foam as the foamed structure in the foamed sealing material of the present invention is obtained by impregnating a non-foamed resin molded article made of a resin composition containing a thermoplastic polymer with a high-pressure gas (particularly an inert gas). The resin composition containing a melted thermoplastic polymer may be impregnated with a gas (particularly an inert gas) under pressure, and then subjected to molding with pressure reduction. May be formed.

  Specifically, when producing a resin foam by a batch method, as a method for producing an unfoamed resin molded product, for example, a thermoplastic polymer and powder particles and other additives used as necessary are used. A method of forming a resin composition containing a extruder using a single screw extruder, a twin screw extruder, or the like, and a resin composition similar to the above mixed with a blade of a roller, a cam, a kneader, a Banbury type, or the like. Examples thereof include a method of kneading uniformly using a smelting machine, press forming to a predetermined thickness using a hot plate press, a method of forming using an injection molding machine, and the like. What is necessary is just to shape | mold by the appropriate method from which the molded object of desired shape and thickness is obtained. Put the unfoamed resin molded product (molded product of the resin composition) thus obtained in a pressure vessel (high pressure vessel), and inject (introduce) high pressure gas (especially inert gas, further carbon dioxide), Gas impregnation step for impregnating a high-pressure gas into an unfoamed resin molding, releasing the pressure (usually up to atmospheric pressure) when the sufficiently high-pressure gas is impregnated, and generating bubble nuclei in the thermoplastic polymer Bubbles are formed in the thermoplastic polymer through a depressurization step, and optionally (if necessary), a heating step of heating to grow bubble nuclei. Note that bubble nuclei may be grown at room temperature without providing a heating step. After growing the bubbles in this way, a resin foam can be obtained by rapidly cooling with cold water or the like as necessary to fix the shape. The shape of the unfoamed resin molded product is not particularly limited, and may be any of a roll shape, a plate shape, and the like. The introduction of high-pressure gas may be performed continuously or discontinuously. Furthermore, as a heating method for growing bubble nuclei, a known or conventional method such as a water bath, an oil bath, a hot roll, a hot air oven, a far infrared ray, a near infrared ray, or a microwave can be employed. Furthermore, the unfoamed resin molded product (unfoamed molded product) to be used for foaming is not limited to a sheet-like product, and can have various shapes (for example, a prismatic shape) depending on the application. Moreover, the non-foamed resin molded product used for foaming can be produced by other molding methods besides extrusion molding, press molding, and injection molding.

  On the other hand, in the case of producing a resin foam by a continuous method, for example, a resin composition containing a thermoplastic polymer and powder particles and other additives used as necessary is converted into a single screw extruder, a twin screw extruder, or the like. Kneading impregnation by injecting (introducing) high-pressure gas (especially inert gas or carbon dioxide) and impregnating the resin composition with high-pressure gas while kneading using an extruder such as a machine. The pressure can be released by extruding the resin composition through a process, a die provided at the tip of the extruder, etc. (usually up to atmospheric pressure), and can be produced by a molding decompression process in which molding and foaming are performed simultaneously. In some cases (if necessary), a heating step of growing bubbles by heating may be provided. After growing the bubbles in this way, a resin foam can be obtained by rapidly cooling with cold water or the like as necessary to fix the shape. The kneading impregnation step and the molding decompression step can be performed using an injection molding machine or the like in addition to the extruder. Moreover, what is necessary is just to select suitably the method of obtaining the resin foam of sheet shape, prismatic shape, and other arbitrary shapes.

  The mixing amount of the gas is not particularly limited, but is, for example, about 2 to 10% by weight with respect to the total amount of the thermoplastic polymer in the resin composition. What is necessary is just to mix suitably adjusting so that a desired density and expansion ratio may be obtained.

  In the gas impregnation step in the batch method or the kneading impregnation step in the continuous method, the pressure when impregnating the unfoamed resin molded product or resin composition with the gas can be appropriately selected in consideration of the type of gas and operability. For example, when an inert gas is used as the gas, particularly carbon dioxide, it is 6 MPa or more (for example, about 6 to 100 MPa), preferably 8 MPa or more (for example, about 8 to 100 MPa). When the gas pressure is lower than 6 MPa, the bubble growth during foaming is remarkable, the bubble diameter becomes too large, and disadvantages such as, for example, a reduction in the dustproof effect are likely to occur, which is not preferable. This is because, when the pressure is low, the amount of gas impregnation is relatively small compared to when the pressure is high, and the number of bubble nuclei formed is reduced due to a decrease in the bubble nucleus formation rate. This is because the bubble diameter becomes extremely large. Further, in the pressure region lower than 6 MPa, the bubble diameter and the bubble density change greatly only by slightly changing the impregnation pressure, so that it is difficult to control the bubble diameter and the bubble density.

  The temperature at which high-pressure gas is impregnated into a non-foamed resin molded product or resin composition in a gas impregnation step in a batch method or a kneading impregnation step in a continuous method varies depending on the type of gas used or the type of thermoplastic polymer, and is wide. Although it can be selected within a range, it is, for example, about 10 to 350 ° C. in consideration of operability. For example, in a batch method, the impregnation temperature when impregnating a high-pressure gas into a sheet-like unfoamed resin molded product is about 10 to 250 ° C. (preferably 40 to 230 ° C.). In the continuous method, the temperature at which high-pressure gas is injected into the resin composition and kneaded is generally about 60 to 350 ° C. When carbon dioxide is used as the high-pressure gas, the temperature during impregnation (impregnation temperature) is preferably 32 ° C. or higher (particularly 40 ° C. or higher) in order to maintain a supercritical state.

  In the decompression step, the decompression speed is not particularly limited, but is preferably about 5 to 300 MPa / second in order to obtain uniform fine bubbles. Moreover, the heating temperature in the said heating process is about 40-250 degreeC (preferably 60-250 degreeC), for example.

  In addition, according to such a method for producing a resin foam, a resin foam having a high expansion ratio can be produced, and thus there is an advantage that a thick resin foam can be produced. For example, when producing a resin foam by a continuous method, in order to maintain the pressure inside the extruder in the kneading impregnation step, the gap of the die attached to the tip of the extruder is as narrow as possible (usually 0.1 to 1). 0.0 mm). Therefore, in order to obtain a thick resin foam, the resin composition extruded through a narrow gap must be foamed at a high magnification. Conventionally, a foam that is formed because a high foaming magnification cannot be obtained. Has been limited to a thin thickness (for example, about 0.5 to 2.0 mm). On the other hand, the resin foam manufactured using high-pressure gas can continuously obtain a foam having a final thickness of 0.50 to 5.00 mm. In order to obtain such a thick resin foam, the relative density of the resin foam (density after foaming / density in an unfoamed state) is 0.02 to 0.30 (preferably 0.05 to 0). .25) is desirable. When the relative density exceeds 0.30, foaming is insufficient, which may cause a problem in flexibility, and when it is less than 0.02, the strength of the resin foam may be remarkably lowered.

In the foamed sealing material of the present invention, the density (apparent density) of the foamed structure is not particularly limited, but when the resin foam is used as the foamed structure, the density of the resin foam is shock absorption, step following ability, etc. in terms of, it is preferable 0.20 g / cm ³ or less (preferably 0.15 g / cm ³ or less, more preferably 0.13 g / cm ³ or less). The lower limit of the apparent density of the resin foam is preferably 0.02 g / cm ³ or more (preferably 0.03 g / cm ³ or more).

  The density of the resin foam can be controlled, for example, by adjusting the expansion ratio by the amount or pressure of gas impregnated in the resin composition when the resin foam is produced.

The density of the foam structure is determined as follows. The foam structure is punched with a 40 mm × 40 mm punching blade mold, and the dimensions of the punched sample are measured. Further, the thickness is measured with a 1/100 dial gauge having a measurement terminal diameter (φ) of 20 mm. From these values, the volume of the foam structure is calculated. Next, the weight of the foam structure is measured with an upper pan balance having a minimum scale of 0.01 g or more. From these values, the apparent density (g / cm ³ ) of the foam structure is calculated.

  The thickness, relative density, and density (apparent density) of the resin foam are, for example, operations such as temperature, pressure, and time in the gas impregnation process and the kneading impregnation process, depending on the type of gas and thermoplastic polymer used. It can be adjusted by appropriately selecting and setting conditions, operating conditions such as pressure reduction speed, temperature, pressure, etc. in the pressure reduction process or molding pressure reduction process, and heating temperature in the heating process after pressure reduction or pressure reduction after molding.

  In addition, the thickness of the foam structure (particularly the resin foam) can be adjusted by obtaining a thickness larger than a desired thickness and then performing a cutting process (for example, a slicing process) or the like so as to obtain a desired thickness.

  The thickness of the foam structure (particularly the resin foam) in the foam sealing material is preferably 0.1 to 2.0 mm, more preferably 0.2 to 1.5 mm, and even more preferably from the viewpoint of impact absorption. Is 0.5 to 1.2 mm.

(Adhesive layer)
The pressure-sensitive adhesive layer of the foamed sealing material of the present invention is a pressure-sensitive adhesive layer provided on at least one side of the foam structure, and is a pressure-sensitive adhesive layer containing a polyoxyalkylene polymer as a main component. The pressure-sensitive adhesive layer of the foamed sealing material of the present invention is formed of a pressure-sensitive adhesive composition containing a polyoxyalkylene polymer as a main component. In the present specification, the “pressure-sensitive adhesive composition” includes the meaning of “a composition for forming a pressure-sensitive adhesive layer”. Further, the “pressure-sensitive adhesive composition containing a polyoxyalkylene polymer as a main component” may be simply referred to as “pressure-sensitive adhesive composition”.

  Since the pressure-sensitive adhesive layer of the foamed sealing material of the present invention contains a polyoxyalkylene polymer as a main component, it is rich in stress relaxation, flexible, and excellent in step absorption performance and impact absorption performance in a thin thickness. .

The polyoxyalkylene polymer is not particularly limited as long as it has a repeating unit represented by the following general formula (1) in the main chain of the polymer, but a polyorganosiloxane structure can be introduced by hydrosilylation to form a crosslinked structure. A polyoxyalkylene polymer having at least one alkenyl group in one molecule is preferable from the viewpoint that it can be produced.
Formula (1): —R ¹ —O—
(Wherein R ¹ is an alkylene group)

R ¹ is preferably a linear or branched alkylene group having 1 to 14 carbon atoms, and more preferably a linear or branched alkylene group having 2 to 4 carbon atoms.

Specific examples of the repeating unit represented by the general formula (1) include —CH ₂ O—, —CH ₂ CH ₂ O—, —CH ₂ CH (CH ₃ ) O—, —CH ₂ CH (C ₂ H _{5 ) O -, - CH 2 C} (CH 3) 2 O -, - CH 2 CH 2 CH 2 CH 2 O- and the like. The main chain skeleton of the polyoxyalkylene polymer may be composed of only one type of repeating unit, or may be composed of two or more types of repeating units. In particular, from the viewpoints of availability and workability, a polymer having —CH ₂ CH (CH ₃ ) O— as the main repeating unit is preferred. The main chain of the polymer may contain a repeating unit other than the oxyalkylene group. In this case, the total of oxyalkylene units in the polymer is preferably 80% by weight or more, particularly preferably 90% by weight or more.

  The polyoxyalkylene polymer may be a linear polymer or a branched polymer, and may be a mixture thereof, but in order to obtain good adhesion, the linear polymer is 50 It is preferable to contain it by weight% or more.

  The molecular weight of the polyoxyalkylene polymer is preferably 500 to 50,000 in terms of number average molecular weight, and more preferably 5,000 to 30,000. If the number average molecular weight is less than 500, the resulting pressure-sensitive adhesive layer (cured product) tends to be too brittle, and conversely, if the number average molecular weight exceeds 50,000, the viscosity becomes too high and workability is high. Since it tends to be remarkably lowered, it is not preferable. The number average molecular weight here is a value determined by a gel permeation chromatography (GPC) method.

  In addition, the polyoxyalkylene polymer preferably has a weight average molecular weight to number average molecular weight ratio (Mw / Mn) of 1.6 or less and a relatively narrow molecular weight distribution. When the Mw / Mn is 1.6 or less, the viscosity of the pressure-sensitive adhesive composition containing the polyoxyalkylene polymer is lowered, and workability is improved. Therefore, Mw / Mn is more preferably 1.5 or less, and even more preferably 1.4 or less. In addition, Mw / Mn here is a value calculated | required by the gel permeation chromatography (GPC) method.

Here, the measurement of the molecular weight by GPC method is a polystyrene conversion value measured using a GPC apparatus (HLC-8120GPC) manufactured by Tosoh Corporation, and the measurement conditions are as follows.
Sample concentration: 0.2% by weight (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
Column: Sample column TSKgel GMH-H (S)
Detector: Differential refractometer

  In the polyoxyalkylene polymer having at least one alkenyl group in one molecule, the alkenyl group is not particularly limited, but an alkenyl group represented by the following general formula (2) is preferable.

General formula (2): H ₂ C═C (R ² )
(Wherein R ² is hydrogen or a methyl group)

  The bonding mode of the alkenyl group to the polyoxyalkylene polymer is not particularly limited, and examples thereof include a direct bond of an alkenyl group, an ether bond, an ester bond, a carbonate bond, a urethane bond, and a urea bond.

Specific examples of the polyoxyalkylene polymer having at least one alkenyl group in one molecule include
Formula _{(3): {H 2 C} = C (R 3a) -R 4a -O} a 1 R 5a
Wherein R ^3a is hydrogen or a methyl group, R ^4a is a divalent hydrocarbon group having 1 to 20 carbon atoms, and one or more ether groups may be contained, R ^5a is a polyoxy (It is an alkylene polymer residue, and a ₁ is a positive integer.)
The polymer shown by these is mentioned. R ^4a in the formula, _{specifically, -CH 2 -, - CH 2} CH 2 -, - CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH 2 CH 2 CH ₂ CH ₂ —, —CH ₂ CH ₂ OCH ₂ CH ₂ —, —CH ₂ CH ₂ OCH ₂ CH ₂ CH ₂ — and the like can be mentioned, but —CH ₂ — is preferred from the viewpoint of ease of synthesis. .

Specific examples of the polyoxyalkylene polymer having at least one alkenyl group in one molecule include
Formula _{(4): {H 2 C} = C (R 3b) -R 4b -OCO} a 2 R 5b
(Wherein R ^3b is hydrogen or a methyl group, R ^4b is a divalent hydrocarbon group having 1 to 20 carbon atoms, and one or more ether groups may be contained, R ^5b is a polyoxy An alkylene polymer residue, and a ₂ is a positive integer.)
The polymer which has an ester bond shown by these is mentioned.

Specific examples of the polyoxyalkylene polymer having at least one alkenyl group in one molecule include
General formula (5): {H ₂ C═C (R ^3c )} a ₃ R ^5c
(Wherein R ^3c is hydrogen or a methyl group, R ^5c is a polyoxyalkylene polymer residue, and a ₃ and a ₃ are positive integers.)
The polymer shown by these is also mentioned.

Furthermore, as a specific example of a polyoxyalkylene polymer having at least one alkenyl group in one molecule,
Formula _{(6): {H 2 C} = C (R 3d) -R 4d -O (CO) O} a 4 R 5d
Wherein R ^3d is hydrogen or a methyl group, R ^4d is a divalent hydrocarbon group having 1 to 20 carbon atoms, and one or more ether groups may be contained, R ^5d is a polyoxy alkylene polymer residues, a ₄ is a positive integer.)
The polymer which has a carbonate bond shown by these is also mentioned.

 In a polyoxyalkylene polymer having at least one alkenyl group in one molecule, there are at least one, preferably 1 to 5, more preferably 1.5 to 3 alkenyl groups in one molecule. It is good to do. If the number of alkenyl groups contained in one molecule is less than 1, the curability is insufficient, and if it exceeds 5, the network structure becomes too dense and may not exhibit good adhesive properties. .

 A polyoxyalkylene polymer (especially a polyoxyalkylene polymer having at least one alkenyl group in one molecule) can be synthesized according to the method described in JP-A No. 2003-292926, and is commercially available. For those that are, commercially available products can be used as they are.

  Since the pressure-sensitive adhesive layer of the foamed sealing material of the present invention contains a polyoxyalkylene polymer (particularly a polyoxyalkylene polymer having at least one alkenyl group in one molecule) as a main component, The content of the polyoxyalkylene polymer (especially a polyoxyalkylene polymer having at least one alkenyl group in one molecule) in the pressure-sensitive adhesive layer is 50% by weight or more (for example, , 50 to 100% by weight), and more preferably 60% by weight or more (for example, 60 to 100% by weight). When the content is less than 50% by weight, the stress relaxation property and flexibility are lowered, and there may be a problem in terms of the step absorbability performance and the impact absorption performance.

As described above, the pressure-sensitive adhesive layer of the foam sealing material of the present invention is formed of a pressure-sensitive adhesive composition containing a polyoxyalkylene polymer as a main component, and is suitable for imparting an appropriate cohesive force. It is preferable that it is comprised from the hardened | cured material which hardened the adhesive composition containing the following (A)-(C) component. That is, the pressure-sensitive adhesive layer of the foamed sealing material of the present invention is preferably formed of a pressure-sensitive adhesive composition containing the following components (A) to (C).
(A): The above polyoxyalkylene polymer (especially a polyoxyalkylene polymer having at least one alkenyl group in one molecule).
(B): Compound containing two or more hydrosilyl groups in one molecule (C): Hydrosilylation catalyst

  (B) As a compound containing two or more hydrosilyl groups in one molecule, any compound having a hydrosilyl group (a group having a Si—H bond) can be used without particular limitation. From the aspect of compatibility with the component (A), an organohydrogenpolysiloxane modified with an organic component is particularly preferable. The polyorganohydrogensiloxane modified with the organic component is more preferably one having 2 to 8 hydrosilyl groups on average in one molecule. In addition, (B) the compound containing 2 or more hydrosilyl groups in 1 molecule is used individually or in combination of 2 or more types.

（式中、２≦ｍ₁＋ｎ₁≦５０、２≦ｍ₁、０≦ｎ₁である。Ｒ^6aは、主鎖の炭素数が２〜２０の炭化水素基で１個以上のフェニル基を含有してもよい）、

（式中、０≦ｍ₂＋ｎ₂≦５０、０≦ｍ₂、０≦ｎ₂である。Ｒ^6bは、主鎖の炭素数が２〜２０の炭化水素基で１個以上のフェニル基を含有してもよい）、

（式中、３≦ｍ₃＋ｎ₃≦２０、２≦ｍ₃≦１９、０≦ｎ₃＜１８である。Ｒ^6cは、主鎖の炭素数が２〜２０の炭化水素基で１個以上のフェニル基を含有してもよい）等で示される鎖状又は環状のものが挙げられる。 Specifically showing the structure of the polyorganohydrogensiloxane, for example,

(In the formula, 2 ≦ m ₁ + n ₁ ≦ 50, 2 ≦ m ₁ , 0 ≦ n _1. R ^6a is a hydrocarbon group having 2 to 20 carbon atoms in the main chain, and one or more phenyl groups. May be contained),

(In the formula, 0 ≦ m ₂ + n ₂ ≦ 50, 0 ≦ m ₂ , 0 ≦ n _2. R ^6b is a hydrocarbon group having 2 to 20 carbon atoms in the main chain, and one or more phenyl groups. May be contained),

(In the formula, 3 ≦ m ₃ + n ₃ ≦ 20, 2 ≦ m ₃ ≦ 19, 0 ≦ n ₃ <18. R ^6c is one or more hydrocarbon groups having 2 to 20 carbon atoms in the main chain. Or may be a chain or a cyclic group represented by the above.

（式中、１≦ｍ₄＋ｎ₄≦５０、１≦ｍ₄、０≦ｎ₄である。Ｒ^6dは、主鎖の炭素数が２〜２０の炭化水素基で１個以上のフェニル基を含有してもよい。２≦ｂ₁である。Ｒ^8aは２〜４価の有機基であり、Ｒ^7aは２価の有機基である。ただし、Ｒ^7aは、Ｒ^8aの構造によってはなくても構わない。）、

（式中、０≦ｍ₅＋ｎ₅≦５０、０≦ｍ₅、０≦ｎ₅である。Ｒ^6eは、主鎖の炭素数が２〜２０の炭化水素基で１個以上のフェニル基を含有してもよい。２≦ｂ₂である。Ｒ^8bは２〜４価の有機基であり、Ｒ^7bは２価の有機基である。ただし、Ｒ^7bは、Ｒ^8bの構造によってはなくても構わない。）、又は

（式中、３≦ｍ₆＋ｎ₆≦５０、１≦ｍ₆、０≦ｎ₆である。Ｒ^6fは、主鎖の炭素数が２〜２０の炭化水素基で１個以上のフェニル基を含有してもよい。２≦ｂ₃である。Ｒ^8cは２〜４価の有機基であり、Ｒ^7cは２価の有機基である。ただし、Ｒ^7cは、Ｒ^8cの構造によってはなくても構わない。）
で示されるもの等が挙げられる。 Furthermore, as a specific example of the structure of the polyorganohydrogensiloxane, the following units having two or more of the above units are provided.

(Wherein the _{1 ≦ m 4 + n 4 ≦} 50,1 ≦ m 4, 0 a ≦ n ₄ .R ^6d is the backbone one or more phenyl groups with a hydrocarbon group from 2 to 20 carbon atoms in the 2 ≦ b ₁ , R ^8a is a divalent to tetravalent organic group, and R ^7a is a divalent organic group, provided that R ^7a is not ^{dependent on} the structure of R ^8a . It does not matter.)

(In the formula, 0 ≦ m ₅ + n ₅ ≦ 50, 0 ≦ m ₅ , 0 ≦ n _5. R ^6e is a hydrocarbon group having 2 to 20 carbon atoms in the main chain, and one or more phenyl groups. 2 ≦ b ₂ , R ^8b is a divalent to tetravalent organic group, and R ^7b is a divalent organic group, provided that R ^7b is not ^{dependent on} the structure of R ^8b . Or)

(In the formula, 3 ≦ m ₆ + n ₆ ≦ 50, 1 ≦ m ₆ , 0 ≦ n _6. R ^6f is a hydrocarbon group having 2 to 20 carbon atoms in the main chain, and is one or more phenyl groups. 2 ≦ b ₃ , R ^8c is a divalent to tetravalent organic group, and R ^7c is a divalent organic group, provided that R ^7c is not ^{dependent on} the structure of R ^8c . It does not matter.)
The thing etc. which are shown by are mentioned.

  The component (B) preferably has good compatibility with the component (A) and the component (C) or good dispersion stability in the system. In particular, when the viscosity of the entire system is low, if a component (B) having low compatibility with each of the above components is used, phase separation may occur and poor curing may occur.

（式中、ｎ₇は４以上１０以下の整数である、）

（式中、２≦ｍ₈≦１０、０≦ｎ₈≦５であり、Ｒ^6gは炭素数８以上の炭化水素基である。） Specific examples of the component (B) having relatively good compatibility with the component (A) and the component (C) or relatively good dispersion stability include the following.

(In the formula, n ₇ is an integer of 4 or more and 10 or less.)

(In the formula, 2 ≦ m ₈ ≦ 10, 0 ≦ n ₈ ≦ 5, and R ^6g is a hydrocarbon group having 8 or more carbon atoms.)

（式中、２≦ｍ₉≦２０、１≦ｎ₉≦２０である。） Preferable specific examples of the component (B) include polymethylhydrogensiloxane. In order to ensure compatibility with the component (A) and adjust the amount of SiH, α-olefin, styrene, α- Compounds modified with methyl styrene, allyl alkyl ether, allyl alkyl ester, allyl phenyl ether, allyl phenyl ester and the like are exemplified, and the following structures are given as an example.

(Wherein 2 ≦ m ₉ ≦ 20 and 1 ≦ n ₉ ≦ 20)

  (B) A component can be synthesize | combined by a well-known method, and about a commercially available thing, a commercial item can be used as it is.

In the present invention, the “hydrosilylation catalyst” of the component (C) is not particularly limited, and any one can be used. Specifically, chloroplatinic acid; platinum alone; solid platinum supported on a carrier such as alumina, silica, carbon black; platinum-vinylsiloxane complex {for example, Pt _n (ViMe ₂ SiOSiMe ₂ Vi) _m , Pt [(MeViSiO) ₄ ] _m, etc.]; platinum-phosphine complex {eg, Pt (PPh ₃ ) ₄ , Pt (PBu ₃ ) ₄ etc.}; platinum-phosphite complex {eg, Pt [P (OPh) ₃ ] ₄ , Pt [P (OBu) ₃ ] ₄ etc.}; Pt (acac) ₂ ; platinum-hydrocarbon complexes described in Ashby et al. US Pat. Nos. 3,159,601 and 3,159,662; Lamoreaux et al., US Pat. And platinum alcoholate catalysts described in the above No. (In the above formula, Me represents a methyl group, Bu represents a butyl group, Vi represents a vinyl group, Ph represents a phenyl group, acac represents acetylacetonate, and n and m represent an integer.)

Examples of catalysts other than platinum compounds include RhCl (PPh ₃ ) ₃ , RhCl ₃ , Rh / Al ₂ O ₃ , RuCl ₃ , IrCl ₃ , FeCl ₃ , AlCl ₃ , PdCl ₂ .2H ₂ O, NiCl _2. , TiCl _{4 and the} like.

These catalysts may be used alone or in combination of two or more. From the viewpoint of catalytic activity, chloroplatinic acid, platinum-phosphine complex, platinum-vinylsiloxane complex, Pt (acac) _{2 and the} like are preferable.

In the pressure-sensitive adhesive composition containing the components (A) to (C), the blending amount of the component (C) is not particularly limited, but from the viewpoint of securing the pot life of the pressure-sensitive adhesive composition, the component (A) In general, it is 1 × 10 ⁻¹ mol or less, preferably 5.3 × 10 ⁻² mol or less, particularly preferably 3.5 × 10 ⁻² mol or less, particularly preferably 1. 4 × 10 ⁻³ mol or less. When it exceeds 1 × 10 ⁻¹ mol with respect to 1 mol of the alkenyl group in the component (A), the finally obtained pressure-sensitive adhesive layer is easily yellowed and causes contamination. In addition, when there are too few compounding quantities of (C) component, since the cure rate of this adhesive composition tends to become slow and sclerosis | hardenability tends to become unstable, the compounding quantity of (C) component is 8.9x. 10 ⁻⁵ mol or more is preferable, and 1.8 × 10 ⁻⁴ mol or more is more preferable.

  In the pressure-sensitive adhesive composition containing the components (A) to (C), the hydrosilyl group of the component (B) has a functional group ratio of 0.3 or more and less than 2 with respect to the alkenyl group of the component (A). It is preferably contained (blended), more preferably in the range of 0.4 or more and less than 1.8, and still more preferably in the range of 0.5 or more and less than 1.5. When the functional group ratio is more than 2, the crosslink density of the formed pressure-sensitive adhesive layer becomes high, and it may become impossible to obtain pressure-sensitive adhesive properties. On the other hand, when the functional group ratio is less than 0.3, the formed pressure-sensitive adhesive layer is too cross-linked, and there are cases where adhesive residue is generated at the time of re-peeling and property retention is lowered at high temperatures.

  Thus, in the pressure-sensitive adhesive composition containing the components (A) to (C), the pressure-sensitive adhesive layer formed is good by selecting the blending ratio of the components (A) and (B) within a specific range. The adhesive layer can be obtained by curing at a sufficiently high line speed for practical use.

  In addition, the storage stability improving agent may be added to the adhesive composition (especially, the adhesive composition containing the components (A) to (C)) for the purpose of improving storage stability. As the storage stability improver, a known compound known as a storage stabilizer for the component (B) can be used without limitation. For example, a compound containing an aliphatic unsaturated bond, an organic phosphorus compound, an organic sulfur compound, a nitrogen-containing compound, a tin compound, an organic peroxide, or the like can be preferably used. More specifically, 2-benzothiazolyl sulfide, benzothiazole, thiazole, dimethylacetylene dicarboxylate, diethylacetylene dicarboxylate, 2,6-di-t-butyl-4-methylphenol, butylhydroxyanisole, Vitamin E, 2- (4-morpholinyldithio) benzothiazole, 3-methyl-1-buten-3-ol, 2-methyl-3-buten-2-ol, acetylenically unsaturated group-containing organosiloxane, acetylene Examples include alcohol, 3-methyl-1-butyl-3-ol, diallyl fumarate, diallyl maleate, diethyl fumarate, diethyl maleate, dimethyl maleate, 2-pentenenitrile, and 2,3-dichloropropene.

  If necessary, an adhesion-imparting agent for improving tackiness (adhesiveness) may be added to the pressure-sensitive adhesive layer. Examples of the adhesion imparting agent include various silane coupling agents and epoxy resins. Among them, the silane coupling agent having a functional group such as an epoxy group, a methacryloyl group, or a vinyl group is a curability of the pressure-sensitive adhesive composition (particularly, a curability of the pressure-sensitive adhesive composition containing the components (A) to (C)). This is preferable because it has a small effect on the adhesiveness and is highly effective in developing the adhesiveness of the pressure-sensitive adhesive layer.

  Moreover, the catalyst for making a silyl group or an epoxy group react can be added together with the silane coupling agent and epoxy resin as said adhesion imparting agent. In addition, in using these, the influence with respect to hydrosilylation reaction must be considered.

  Furthermore, various fillers, antioxidants, ultraviolet absorbers, pigments, surfactants, and silicon compounds may be appropriately added to the pressure-sensitive adhesive layer.

Specific examples of the filler include silica fine powder, calcium carbonate, clay, talc, titanium oxide, zinc white, diatomaceous earth, barium sulfate and the like. In particular, silica fine powder, especially fine powder silica having a particle size of about 50 to 70 nm (BET specific surface area of 50 to 380 m ² / g) is preferable. Among them, surface-treated hydrophobic silica improves strength in a preferable direction. It is particularly preferable because it has a large function to perform.

  Furthermore, a tackifier resin may be added to the pressure-sensitive adhesive layer as necessary in order to improve characteristics such as tack. Examples of the tackifier resin include terpene resin, terpene phenol resin, petroleum resin, rosin ester, and the like, and can be freely selected according to use.

  From the viewpoint of improving the characteristics, resins such as a phenol resin, an acrylic resin, a styrene resin, and a xylene resin may be added to the pressure-sensitive adhesive layer. Moreover, adhesive components, such as an acrylic adhesive, a styrene block adhesive, and an olefin adhesive, may be added for the same purpose.

  Moreover, the solvent (organic solvent) may be added to the adhesive composition from the point of workability | operativity. In particular, the pressure-sensitive adhesive composition containing the components (A) to (C) may be added with an organic solvent such as toluene, xylene, ethyl acetate, methyl ethyl ketone, etc., but the polyoxyalkylene type which is the component (A) By appropriately selecting the molecular weight of the polymer and / or the molecular weight or structure of the hydrosilyl group-containing compound as component (B), a composition that can flow at room temperature can be obtained with substantially no addition of a solvent or addition of a small amount. Can do.

  That is, the organic solvent content in the composition is less than 20% by weight, preferably less than 5% by weight, and the viscosity of the pressure-sensitive adhesive composition at 230 ° C. is 100 Pa · s or less, preferably 50 Pa · s or less. A pressure-sensitive adhesive composition (particularly a pressure-sensitive adhesive composition containing the components (A) to (C)) can be obtained. When the viscosity of the pressure-sensitive adhesive composition exceeds 100 Pa · s, it may be difficult to apply with a normal coating apparatus such as a roll coater method, a reverse coater method, or a doctor blade method.

  As described above, the pressure-sensitive adhesive composition (particularly the pressure-sensitive adhesive composition containing the components (A) to (C)) has fluidity even at room temperature without adding an organic solvent or only with a small amount of an organic solvent. Therefore, it is effective as a countermeasure for the indoor environment and skin irritation problems caused by solvent volatilization to the environment and the solvent contained in the adhesive layer. Moreover, when it has fluidity at room temperature, problems such as temperature control and tank heating, which are problems when applying a hot melt adhesive or the like, do not occur. Further, when the pressure-sensitive adhesive composition containing the components (A) to (C) is used as the pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition cures quickly only by heating, so that UV curing or electron beam curing is performed. No new equipment is required. Moreover, when using the adhesive composition containing (A)-(C) component as an adhesive composition, this adhesive composition is hardened | cured by addition reaction of the Si-H group with respect to the alkenyl group using the hydrosilylation catalyst. Therefore, the curing speed is very fast, which is convenient for line production.

  The pressure-sensitive adhesive composition can be prepared by mixing a polyoxyalkylene polymer and, if necessary, various additives using a known method. For example, the pressure-sensitive adhesive composition containing the components (A) to (C) is prepared by mixing the components (A) to (C) with various additives as necessary using known methods. Can be prepared.

  Although the formation method in particular of an adhesive layer is not restrict | limited, For example, the method of apply | coating and forming an adhesive composition on a predetermined surface is mentioned. In the formation method, heating, drying, light irradiation, pretreatment, and the like may be performed as necessary.

  As a typical method for forming a pressure-sensitive adhesive layer, a pressure-sensitive adhesive composition (particularly a pressure-sensitive adhesive composition containing components (A) to (C)) is mixed with an organic solvent as necessary, and a stirring device having a vacuum function. And defoaming by stirring in a vacuum state (under vacuum), applying (casting) the pressure-sensitive adhesive composition after vacuum defoaming onto various supports, and heat-treating it into a sheet. Is mentioned.

  For application to the support, for example, a known coater such as a roll coater such as gravure, kiss or comma, a die coater such as slot or phantom, a squeeze coater or a curtain coater can be used.

  The heat treatment conditions (particularly the heat treatment conditions of the pressure-sensitive adhesive composition containing the components (A) to (C)) are not particularly limited as long as the pressure-sensitive adhesive layer can be obtained, but are 50 to 200 ° C. (preferably 100 to 160 ° C.). Then, it is preferable to heat for about 0.01 to 24 hours (preferably 0.05 to 4 hours).

  In addition, what is necessary is just to use a well-known stirring apparatus with a vacuum apparatus as a stirring apparatus provided with said vacuum function, Specifically, a planetary type (revolution / autorotation system) stirring deaerator, a deaerator with a disper, etc. Is mentioned. Moreover, as a grade of the pressure reduction at the time of performing vacuum defoaming, 10 kPa or less is preferable and 3 kPa or less is more preferable. Moreover, although stirring time changes also with the amount of processing of a stirring apparatus and a fluid, about 0.5 to 2 hours are preferable.

  Although the thickness of an adhesive layer is not specifically limited, 5-1000 micrometers is preferable from points, such as adhesiveness, stress relaxation property, and the mounting property to clearance (gap), More preferably, it is 10-400 micrometers. The pressure-sensitive adhesive layer may have either a single layer or a multilayer.

(Release liner)
The pressure-sensitive adhesive layer surface (adhesive surface) of the foamed sealing material of the present invention may be protected by a release liner (separator) until use. The release liner is used as a protective material for the pressure-sensitive adhesive layer, and is peeled off when the foamed sealing material is used. Note that the release liner is not necessarily provided.

  As such a release liner, a conventional release paper or the like can be used, and is not particularly limited. For example, a substrate having a release treatment layer, a low-adhesive substrate made of a fluoropolymer, and a low adhesion made of a nonpolar polymer. Can be used. As a base material which has the said peeling process layer, the plastic film, paper, etc. which were surface-treated with peeling processing agents, such as a silicone type, a long-chain alkyl type, a fluorine type, and molybdenum sulfide, are mentioned, for example. Examples of the fluorine-based polymer in the low-adhesive substrate made of a fluorine-based polymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer, chloro Examples include fluoroethylene / vinylidene fluoride copolymers. Examples of the nonpolar polymer of the low-adhesive substrate made of a nonpolar polymer include olefin resins (for example, polyethylene and polypropylene). The release liner can be formed by a known or common method. Further, the thickness of the release liner is not particularly limited.

(Other layers)
The foamed sealing material of the present invention may have other layers (for example, an intermediate layer, an undercoat layer, etc.) as long as the effects of the present invention are not impaired. For example, another layer may be provided between the foam structure and the pressure-sensitive adhesive layer.

  In the foamed sealing material of the present invention, as a typical example of another layer in the case where another layer is provided between the foam structure and the pressure-sensitive adhesive layer, an adhesive layer (adhesive intermediate layer) as an intermediate layer is mentioned. It is done. In the foamed sealing material of the present invention, having such an adhesive intermediate layer is sufficient even when the adhesive force between the foamed structure and the pressure-sensitive adhesive layer mainly composed of a polyoxyalkylene polymer is low. Can give throwing power.

  The adhesive that forms such an adhesive intermediate layer is not particularly limited, and examples thereof include acrylic adhesives, rubber adhesives (natural rubber adhesives, synthetic rubber adhesives, etc.), silicone adhesives, and the like. A known pressure-sensitive adhesive such as a polyester-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a polyamide-based pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, or a fluorine-based pressure-sensitive adhesive can be appropriately selected and used. An adhesive can be used individually or in combination of 2 or more types. The pressure-sensitive adhesive may be any type of pressure-sensitive adhesive such as an emulsion-based pressure-sensitive adhesive, a solvent-based pressure-sensitive adhesive, a hot-melt pressure-sensitive adhesive, an oligomer-based pressure-sensitive adhesive, and a solid-type pressure-sensitive adhesive.

  As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive is preferable from the viewpoint of preventing contamination of the adherend.

  That is, in the foam sealing material of the present invention, when the foam structure and the pressure-sensitive adhesive layer mainly composed of the polyoxyalkylene polymer are difficult to adhere, the foam structure and the pressure-sensitive adhesive layer (polyoxyalkylene polymer) It is preferable to provide an adhesive intermediate layer between the adhesive layer and a pressure-sensitive adhesive layer formed of an acrylic adhesive as the adhesive intermediate layer.

  The thickness of the adhesive intermediate layer is preferably 1 to 100 μm, more preferably 2 to 50 μm, from the viewpoint of not adversely affecting the impact absorption and dynamic dust resistance when dropped.

  Moreover, 5-100% is preferable with respect to the thickness of the said adhesive layer, and, as for the thickness of an adhesive intermediate | middle layer, More preferably, it is 10-75%. If the thickness of the adhesive intermediate layer is too thin relative to the thickness of the pressure-sensitive adhesive layer, the anchoring force between the foam structure and the pressure-sensitive adhesive layer may not be exhibited. May adversely affect the shock absorption and dynamic dust resistance of

(Foam sealing material)
The foamed sealing material of the present invention has a pressure-sensitive adhesive layer containing the polyoxyalkylene polymer as a main component (in particular, the above (A) to (C) on one side or both sides of a foam structure (foam). A pressure-sensitive adhesive layer composed of a cured product obtained by curing a pressure-sensitive adhesive composition containing a component). In addition, the foaming sealing material of this invention may have the form on which the sheet-like thing was laminated | stacked, and may have the form wound by roll shape. In addition, the foam sealing material may be processed into various shapes according to the device, member, casing, and the like used.

  For example, the foam sealing material may be formed by applying an adhesive composition on at least one surface of the foam structure to form an adhesive layer, or separately on a predetermined surface on at least one surface of the foam structure. It is produced by transferring the produced pressure-sensitive adhesive layer. Further, when the foamed sealing material has the above-mentioned adhesive layer as an intermediate layer, such a foamed sealing material is, for example, the above-mentioned adhesive intermediate layer (adhesive layer as an intermediate layer) on at least one surface of the foam structure. And a pressure-sensitive adhesive layer (pressure-sensitive adhesive layer mainly composed of a polyoxyalkylene polymer) separately prepared on a predetermined surface is transferred onto the pressure-sensitive adhesive intermediate layer.

  The thickness of the foamed sealing material is not particularly limited, but is preferably about 0.1 mm to 5.0 mm, more preferably about 0.2 mm to 4.0 mm, from the viewpoint of impact absorption, step following ability, and the like. The thickness of the foamed sealing material includes the thickness of the adhesive intermediate layer. Further, the thickness of the foamed sealing material does not include the thickness of the release liner.

  Since the foamed sealing material has a foamed structure, the foamed structure has characteristics (for example, shock absorption, flexibility, step following ability, sealability, dustproof, soundproofing, etc.) inherent to the foamed structure.

  The foamed sealing material also has a pressure-sensitive adhesive layer (particularly a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition containing the components (A) to (C)) mainly composed of a polyoxyalkylene polymer. Since the pressure-sensitive adhesive layer is rich in viscoelasticity, the stress relaxation property and impact absorption property are good, and an appropriate adhesive force is exerted on the adherend. Moreover, the rework property from a to-be-adhered body is also favorable.

  Since the foamed sealing material has a structure in which a specific pressure-sensitive adhesive layer is laminated on the foamed structure, the foamed sealing material is excellent in impact absorption and dynamic dustproofness when dropped. This is because even if a sudden stress concentration occurs due to a drop or the like, a specific pressure-sensitive adhesive has the above-mentioned characteristics, so that the dynamic dustproofness is reduced while maintaining the shock absorption. This is because it can be prevented. The dynamic dustproof property refers to the dustproof property when receiving a large impact such as when falling.

  As a specific example, there is a case where the foam sealing material is used as a shock absorbing material (gasket material) in a display unit window frame (LCD unit window frame) such as a mobile phone or a liquid crystal television. Since the foamed sealing material has a structure in which a specific pressure-sensitive adhesive layer is laminated directly or indirectly on the foamed structure, even if the foamed sealing material receives a large impact, it maintains dustproof performance, Exhibits shock absorption.

  More specifically, when the foam sealing material is mounted as an impact absorbing material on the mobile phone, even if the foam sealing material receives a large impact due to the fall of the mobile phone, etc., while maintaining the dustproof performance, Exhibits shock absorption. For this reason, it is possible to prevent the cellular phone (particularly the display portion of the cellular phone) from being damaged and dust from entering the display portion.

  Thus, the foamed sealing material of the present invention is suitably used as a sealing material around the display.

  When the foam structure of the foam seal material is produced by a foaming method using an inert gas such as carbon dioxide as a foaming agent, the foam seal material generates harmful substances or remains pollutants in the foam structure. Since it is clean and not used, it is particularly suitable for use inside electronic equipment.

  In addition, the foamed sealing material of the present invention is useful as a sealing material, an impact absorbing material, or the like used when various members or parts (for example, optical members) are attached (attached) to a predetermined site. In particular, the foam sealing material can be suitably used even when a small member or component (for example, a small optical member) is mounted on a thin product.

  As an optical member that can be attached (attached) using a foam seal material, for example, an image display member (particularly, a small image display member) attached to an image display device such as a liquid crystal display, an electroluminescence display, or a plasma display. In addition, a camera or a lens (particularly, a small camera or lens) attached to a mobile communication device such as a so-called “mobile phone” or “portable information terminal” can be used.

  Furthermore, the foamed sealing material of the present invention can be used as a sealing material for preventing toner from leaking from the toner cartridge. As described above, examples of the toner cartridge that can be attached using the foam seal material include a toner cartridge used in an image forming apparatus such as a copying machine or a printer.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
(Foam structure)
Polypropylene having a density of 0.9 g / cm ³ and a melt flow rate of 4 at 230 ° C .: 50 parts by weight, ethylene propylene elastomer having a JIS-A hardness of 69: 50 parts by weight, magnesium hydroxide (average particle size: 0) 0.7 μm): 10 parts by weight and 10 parts by weight of carbon were kneaded at a temperature of 200 ° C. with a twin-screw kneader manufactured by Nippon Steel Works, then extruded into strands, cooled to water, and pelletized. Molded. This pellet was put into a single-shaft kneader manufactured by Nippon Steel Works, and carbon dioxide gas was injected under a 220 ° C. atmosphere and a pressure of 13 (12 after injection) MPa. Carbon dioxide gas was injected at a ratio of 5% by weight with respect to the total amount of the polymer. After sufficiently saturating the carbon dioxide gas, it was cooled to a temperature suitable for foaming and then extruded from a die to obtain a foamed structure having an average cell diameter of 100 μm, which was sliced to a thickness of 1 mm.

(Adhesive layer)
Polyoxyalkylene polymer (number average molecular weight: about 20,000) as component (A), hydrosilyl compound as component (B) (alkenyl of polyoxyalkylene group polymer whose hydrosilyl group amount is component (A)) A composition containing a hydrosilylation catalyst as component (C) (0.62 mol with respect to 1 mol of alkenyl groups in component A) as a component (C) The mixture was put into an attached stirring device (device name “Mini Dappo”, manufactured by Seatec Co., Ltd.), and deaerated by stirring for 1 hour in a vacuum state (100 Pa). Next, the vacuum degassed composition was applied (cast) onto a polyester film (thickness: 50 μm) subjected to a release treatment using a roll coater at room temperature so that the thickness of the composition was 200 μm. did. The composition was cured by heating at 130 ° C. for 5 minutes in a heating oven to obtain an adhesive layer (thickness 125 μm).
Next, the pressure-sensitive adhesive sheet (polyester film having been subjected to the release treatment / pressure-sensitive adhesive layer /) is bonded to the pressure-sensitive adhesive layer of the sheet thus obtained by bonding the polyester film (thickness: 50 μm) having been subjected to the release treatment. A polyester film subjected to a release treatment) was obtained.

(Foam sealing material)
An ultra-thin double-sided acrylic adhesive tape (trade name “No. 5601”, manufactured by Nitto Denko Corporation, double-sided adhesive tape / release liner configuration, thickness: 30 μm) is bonded to both sides of the foam structure, and a release liner is attached. A laminate of / double-sided acrylic pressure-sensitive adhesive tape / foamed structure / double-sided acrylic pressure-sensitive adhesive tape / release liner was obtained.
Next, the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is exposed by peeling off the polyester film subjected to the release treatment on the pressure-sensitive adhesive surface exposed by peeling off one release liner of the laminate, Bonded in contact with each other, foam sealing material 1 (polyester film subjected to release treatment / adhesive layer (thickness: 125 μm) / double-sided acrylic adhesive tape (thickness: 30 μm) / foamed structure (thickness: 1 mm) / Double-sided acrylic adhesive tape (thickness: 30 μm) / release liner) was prepared.

Comparative Example 1
On both sides of the foam structure (foam structure of Example 1), an ultra-thin double-sided acrylic adhesive tape (trade name “No. 5601”, manufactured by Nitto Denko Corporation, double-sided adhesive tape / release liner configuration, thickness : 30 μm), and foam sealing material 2 (release liner / double-sided acrylic adhesive tape (thickness: 30 μm) / foamed structure (thickness: 1 mm) / double-sided acrylic adhesive tape (thickness: 30 μm) / release liner Configuration).

Comparative Example 2
Toluene solvent is added to a thermoplastic elastomer resin (trade name “SIS5405”, manufactured by JSR, styrene-isoprene-styrene thermoplastic elastomer resin, styrene component content ratio: 18 mol%), and the solid content concentration is 20 weight. % Dilution was obtained.
The diluted solution is applied to one surface of the foamed structure (foamed structure of Example 1) with a Mayer bar at a coating amount of 15 g / m ² in terms of dry weight (solid content weight). A thermoplastic elastomer resin layer (coat layer) was formed on the surface of the foam structure by heating and drying at 80 ° C. for 3 minutes.
Next, an ultrathin double-sided acrylic adhesive tape (trade name “No. 5601”, manufactured by Nitto Denko Corporation, double-sided adhesive tape / peeling) Liner configuration, thickness: 30 μm), and foam sealing material 3 (thermoplastic elastomer resin layer / foam structure (thickness: 1 mm) / double-sided acrylic adhesive tape (thickness: 30 μm) / release liner configuration) Produced.

Reference example 1
As the foam sealing material, the foam structure of Example 1 was used as it was. The thickness was 1 mm.

Reference example 2
As the foam sealing material, urethane foam (a product in which the foam is supported on one side of the PET base material, thickness: 0.4 mm, trade name “PORON SRS-40P”, manufactured by Roger Inox Co., Ltd.) was used.

Evaluation The following evaluation was performed about the foaming sealing material obtained by said Example and comparative example. The evaluation results are shown in Tables 1 to 3.

(Dynamic dustproof)
Evaluation of dynamic dust resistance is performed when the compression rate is 70% and when the compression rate is 40%. The evaluation results when the compression rate is 70% are shown in Table 1, and when the compression rate is 40%. The evaluation results are shown in Table 2.

The foamed sealing materials of Examples and Comparative Examples were punched into a frame shape (window frame shape) (width: 2 mm) shown in FIG. 1 to prepare an evaluation sample. In the sample for evaluation, all release liners were excluded.
As shown in FIG. 2, this evaluation sample was attached to an evaluation container (an evaluation container for dynamic dustproof evaluation described later, see FIGS. 2 and 3). As shown in FIG. 2, the sample for evaluation is provided between the foam compression plate and the black acrylic plate on the aluminum plate fixed to the base plate. The evaluation container equipped with the evaluation sample is a system in which a certain region inside is closed by the evaluation sample.
As shown in FIG. 2, after mounting the evaluation sample in the evaluation container, 0.1 g of corn starch as dust is put in the powder supply unit, and the evaluation container is put in a drum type drop tester (rotary dropping device). Rotated at a speed of
Then, after rotating a predetermined number of times so that the desired number of collisions is obtained, the powder supply unit passes through the foam seal material to the black acrylic plate on the aluminum plate and the black acrylic plate as the cover plate. The adhered particles were observed with a microscope. Still images were created for the black acrylic plate on the aluminum plate side and the black acrylic plate on the cover plate side, binarized using image analysis software, and the total particle area was measured as the number of particles. The observation was performed in a clean bench to reduce the influence of airborne dust.

  Good when the total particle area of the particles adhering to the black acrylic plate on the aluminum plate side and the particles adhering to the black acrylic plate on the cover plate side is less than 1500 [Pixel × Pixel] (◯) When it was 1500 to 2000 [Pixel × Pixel], it was determined as slightly defective (Δ), and when it exceeded 2000 [Pixel × Pixel], it was determined as defective (×).

  FIG. 2 shows a cutaway end view of an evaluation container (an evaluation container for dynamic dustproof evaluation) equipped with an evaluation sample, and FIG. 3 shows an upper surface of the evaluation container for dynamic dustproof evaluation equipped with an evaluation sample. The figure is shown. FIG. 2 is an end view of the cutting section A-A ′ line with the evaluation sample mounted thereon. The evaluation container can evaluate the impact absorbability and dynamic dust resistance (dust resistance at the time of impact) of the evaluation sample by dropping after mounting the evaluation sample. 2 and 3, 2 is an evaluation container (evaluation container for dynamic dustproof evaluation) equipped with an evaluation sample, 211 is a black acrylic plate (black acrylic plate on the cover plate side), 212 is a black acrylic plate (aluminum) (Black acrylic plate on the plate side), 22 is a sample for evaluation (frame-shaped foam sealing material), 23 is an aluminum plate, 24 is a base plate, 25 is a powder supply unit, 26 is a screw, 27 is a foam compression plate, 28 is The cover plate fixing bracket is shown. The compression rate of the evaluation sample 22 can be controlled by adjusting the thickness of the black acrylic plate 212.

  As shown in Table 1, when the compression rate is 70%, except for Reference Example 1 in which the adhesion treatment is not performed, in Example 1, Comparative Examples 1 and 2, and Reference Example 2, good results were obtained for the dustproof performance. Obtained. However, when the compression ratio is around 70%, the compression state is high, and the impact absorption performance may be lowered. Considering both the impact absorbing performance and the dustproof performance, the dustproof performance at a compression rate of around 40% is important.

  When the compression ratio is 40%, in Reference Example 1 in which the adhesion treatment is not performed, the number of collisions is about 10 times, and the dust particles pass through the evaluation sample (foam seal material), and the number of collisions is about 20 times. Thus, a large amount of dust particles passed through the evaluation sample (foamed sealing material) and entered the evaluation container.

  In Reference Example 2, good dustproof performance was obtained when the compression rate was 70%. However, when the compression rate was 40%, the number of collisions was about 20 and the dustproof property was lowered.

  In Comparative Example 1, good dustproofness could not be obtained even when the number of collisions was 10 times or 20 times. This may be because stress concentration at the adhesive interface is not relaxed, and a part of the double-sided acrylic pressure-sensitive adhesive tape (No. 5601) bonded to the foamed structure may be peeled off.

  In the drum type drop tester, the dropping posture of the evaluation container (evaluation container for dynamic dustproof evaluation) was not controlled and was random. However, it was more likely to fall in a vertical posture than in a horizontal posture. Since the evaluation container is considered to cause bending deformation by colliding with the falling surface, the short side of the evaluation sample (frame-shaped foamed sealing material) fixed to the evaluation container is susceptible to compressive deformation. Permanent distortion and peeling of the pressure-sensitive adhesive layer (peeling of the pressure-sensitive adhesive treatment) are likely to occur.

  In the case of Reference Example 1 in which the adhesion treatment was not performed, dust passed from both short sides of the sample for evaluation and entered the inside. As the number of collisions increased, more dust particles passed through.

  In the case of the comparative example 1, dust has penetrated from only one side, and it is estimated that the double-sided pressure-sensitive adhesive tape (No. 5601) was partially peeled off. As a measure to improve the dust resistance with impacts, it was confirmed that it was not possible to respond by adjusting the adhesive force alone.

  In the case of Example 1, compared with the comparative example and the reference example, the passing dust particles were remarkably small and had good dust resistance. In contrast to Comparative Example 1, it is considered that the pressure-sensitive adhesive layer of Example 1 has stress relaxation properties, and interfacial peeling is suppressed during a drop impact.

(Stripping strength)
The foamed sealing materials of the examples and comparative examples were punched into a circle having a diameter of 20 mm to prepare a measurement sample. In the sample for evaluation, all release liners were excluded. As a measuring device, a micro servo device (device name “Micro Servo MMT250”, manufactured by Shimadzu Corporation) was used.
The sample for measurement is fixed to the support base of the micro servo device, and compressed from the height of 3 mm to the gap of 0.6 mm using the compression jig of the micro servo device (0.6 mm compression). ), Held at a position of 0.6 mm for 30 seconds. In the measurement sample of Example 1, the pressure-sensitive adhesive layer is in contact with the compression jig, and in the measurement sample of Comparative Example 1, the double-sided acrylic adhesive tape (No. 5601) is in contact with the compression jig. In the measurement sample of Example 2, the thermoplastic elastomer resin layer is in contact with the compression jig.
After holding, by moving the compression jig in the vertical direction at a speed of 0.5 mm / sec, pulling is started at a tensile speed of 0.5 mm / sec and peeling strength (tensile strength, tensile load, adhesive force) Was measured. The results are shown in Table 3 and FIG.

  From FIG. 4, the peeling strength showed a peak at a position of 1.1 to 1.4 mm. Table 3 shows peak values.

  From Table 3, the peak value of the peeling strength is 65 N in Comparative Example 1, which is the largest. However, in Comparative Example 1, as shown in FIG. 4, the peel strength is generated immediately after 0.6 mm compression, whereas in Example 1 and Comparative Example 2, the peel strength is from about 1 mm. Occurs and is slower than Comparative Example 1. This is presumably because the viscoelastic effect of the pressure-sensitive adhesive layer and the thermoplastic elastomer resin layer is expressed, and the stress is relaxed at the bonding interface of the pressure-sensitive adhesive treatment.

  From Table 3, it is considered that Example 1 is appropriate as the peel strength from the viewpoint of dust resistance and reworkability.

2 Evaluation container with evaluation sample (evaluation container for dynamic dustproof evaluation)
211 Black acrylic plate (black acrylic plate on the cover plate side)
212 Black acrylic plate (aluminum plate side black acrylic plate)
22 Sample for evaluation (frame-shaped foam sealing material)
23 Aluminum plate 24 Base plate 25 Powder supply unit 26 Screw 27 Foam compression plate 28 Cover plate fixing bracket

Claims (9)

  A foamed sealing material, wherein a pressure-sensitive adhesive layer comprising a polyoxyalkylene polymer as a main component is provided on at least one side of the foamed structure. The foaming sealing material according to claim 1, wherein the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing the following components (A) to (C).
(A): polyoxyalkylene polymer having at least one alkenyl group in one molecule (B): compound having two or more hydrosilyl groups in one molecule (C): hydrosilylation catalyst   The foaming sealing material of Claim 1 or 2 with which the adhesive intermediate | middle layer is provided between the foaming structure and the adhesive layer which has a polyoxyalkylene type polymer as a main component.   The said foaming structure is formed through the process of depressurizing, after impregnating the resin composition containing a thermoplastic polymer with a high-pressure inert gas. Foam sealing material.   The foamed structure is formed through a step of reducing pressure after impregnating a non-foamed resin molded article made of a resin composition containing a thermoplastic polymer with a high-pressure inert gas. The foam sealing material according to any one of the items.   The foamed sealing material according to claim 4 or 5, wherein the foamed structure is formed by further heating after decompression.   The foaming sealing material according to any one of claims 4 to 6, wherein the inert gas is carbon dioxide.   The foamed sealing material according to any one of claims 4 to 7, wherein the inert gas is in a supercritical state.   The foamed sealing material according to any one of claims 1 to 8, which is used for sealing around a display.

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