WO2018131619A1 - Feuille d'amortissement de chocs - Google Patents

Feuille d'amortissement de chocs Download PDF

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Publication number
WO2018131619A1
WO2018131619A1 PCT/JP2018/000380 JP2018000380W WO2018131619A1 WO 2018131619 A1 WO2018131619 A1 WO 2018131619A1 JP 2018000380 W JP2018000380 W JP 2018000380W WO 2018131619 A1 WO2018131619 A1 WO 2018131619A1
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WO
WIPO (PCT)
Prior art keywords
absorbing sheet
impact
mass
resin
sheet
Prior art date
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PCT/JP2018/000380
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English (en)
Japanese (ja)
Inventor
康司 谷内
平池　宏至
弘二 下西
Original Assignee
積水化学工業株式会社
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Filing date
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Application filed by 積水化学工業株式会社 filed Critical 積水化学工業株式会社
Priority to JP2018504298A priority Critical patent/JP7000310B2/ja
Priority to CN201880006432.XA priority patent/CN110191913A/zh
Priority to KR1020197020167A priority patent/KR20190104540A/ko
Publication of WO2018131619A1 publication Critical patent/WO2018131619A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L21/00—Compositions of unspecified rubbers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L21/00—Compositions of unspecified rubbers
    • C08L21/02—Latex
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
    • C08L25/02—Homopolymers or copolymers of hydrocarbons
    • C08L25/04—Homopolymers or copolymers of styrene
    • C08L25/08—Copolymers of styrene
    • C08L25/10—Copolymers of styrene with conjugated dienes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L53/00—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
    • C08L53/02—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers of vinyl-aromatic monomers and conjugated dienes
    • C08L53/025—Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers of vinyl-aromatic monomers and conjugated dienes modified
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
    • C08L9/06—Copolymers with styrene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L91/00—Compositions of oils, fats or waxes; Compositions of derivatives thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F7/00—Vibration-dampers; Shock-absorbers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2207/00—Properties characterising the ingredient of the composition
    • C08L2207/32—Properties characterising the ingredient of the composition containing low molecular weight liquid component
    • C08L2207/322—Liquid component is processing oil

Definitions

  • the present invention relates to a thin shock absorbing sheet, and more particularly to a shock absorbing sheet used in a display device of a portable electronic device.
  • an impact absorbing material for absorbing shock and vibration is provided.
  • electronic devices including a display device, particularly portable electronic devices are required to be thin due to space limitations, and accordingly, the shock absorber is also required to be a thin sheet.
  • a thin impact absorbing material it is widely known that it is formed of a foam made of a polyolefin resin typified by polyethylene. In the foam made of a polyolefin resin, the shape of bubbles is constant. It is considered that the impact absorption performance is improved by controlling the flexibility by controlling the material (see, for example, Patent Document 1).
  • the shock absorbing performance may not be sufficiently improved by simply controlling the shape of the bubbles to be constant and controlling the flexibility.
  • the glass constituting the surface of the display device may be damaged when a relatively large impact force of several tens to hundreds of MPa is applied locally, but the flexibility of the foam sheet made of polyolefin resin is controlled. Even so, it is difficult to sufficiently mitigate such impact force.
  • the present invention has been made in view of the above problems, and an object of the present invention is to have excellent shock absorption performance even when it is thin, and particularly, to absorb relatively large impact force applied locally.
  • An object of the present invention is to provide an impact absorbing sheet capable of improving the performance.
  • the present invention provides the following (1) to (11).
  • the impact-absorbing sheet according to (1) or (2) which comprises a solid resin (A) and a liquid rubber (B).
  • the impact-absorbing sheet according to (3) wherein the resin (A) is a styrene-based thermoplastic elastomer.
  • the impact-absorbing sheet according to (3) or (4) further including process oil (C).
  • the total content of the liquid rubber (B) and the process oil (C) is 10 parts by mass or more and 130 parts by mass or less with respect to 100 parts by mass of the resin (A).
  • the present invention it is possible to provide an impact-absorbing sheet having excellent impact-absorbing performance. For example, even if it is thin, the impact-absorbing sheet improves the absorbing performance against a relatively large impact force applied locally.
  • the impact-absorbing sheet of the present invention has a storage elastic modulus of 1.0 ⁇ 10 5 Pa to 2.5 ⁇ 10 7 Pa, tan ⁇ of 0.3 or more, and a density of 600 kg / m 3 or more.
  • the storage elastic modulus and tan ⁇ mean the storage elastic modulus at 23 ° C. and tan ⁇ at 23 ° C., respectively, unless otherwise specified.
  • the impact-absorbing sheet of the present invention is thin and the impact-absorbing performance can be improved even when a relatively large impact force is locally applied to the resin sheet.
  • the storage elastic modulus is 2.5 ⁇ 10 7 Pa or less and tan ⁇ is 0.3 or more, the point load is easily converted into the surface load and the energy loss is increased. And since the density becomes 600 kg / m 3 or more and the storage elastic modulus becomes 1.0 ⁇ 10 5 Pa or more, the shock wave easily propagates along the surface direction of the resin sheet. It is estimated that performance will be exhibited.
  • the storage elastic modulus of the shock absorbing sheet is preferably 2.0 ⁇ 10 5 Pa or more and 2.0 ⁇ 10 7 Pa or less, more preferably 4.0 ⁇ 10 5 Pa or more, from the viewpoint of improving impact absorbing performance. 0 ⁇ 10 7 Pa or less.
  • tan ⁇ is less than 0.30, the energy loss cannot be increased, and the shock absorption performance cannot be sufficiently improved. From the viewpoint of increasing the energy loss and further improving the impact absorption performance, tan ⁇ is preferably 0.33 or more, and more preferably 0.36 or more.
  • the upper limit of tan ⁇ is not particularly limited, but is preferably 1.5 or less, more preferably 1.2 or less, and still more preferably 0.9 or less, in order to make the storage elastic modulus easily in the above range. Furthermore, if the density of the shock absorbing sheet is less than 600 kg / m 3 , when the shock is applied to the shock absorbing sheet, the impact absorbing sheet cannot be absorbed by the shock absorbing sheet and propagates to the member on the back side. May occur.
  • the density of the impact absorbing sheet is preferably 650 kg / m 3 or more, more preferably 700 kg / m 3 or more, and even more preferably 700 kg / m 3 from the viewpoint of further improving the impact absorbing performance. .
  • the upper limit of the density of the shock absorbing sheet is not particularly limited, but is usually 1200 kg / m 3 or less because of the characteristics of the resin used for the shock absorbing sheet.
  • the peak temperature of tan ⁇ is preferably less than 15 ° C., more preferably from ⁇ 60 ° C. to less than 15 ° C., and even more preferably from ⁇ 50 ° C. to less than 15 ° C. from the viewpoint of improving impact absorption performance.
  • the peak temperature can be within the above range by using a styrene-based thermoplastic elastomer or the like.
  • the thickness of the impact absorbing sheet is preferably 0.02 mm or more and 0.9 mm or less.
  • the thickness of the impact absorbing sheet is more preferably 0.02 mm or more and 0.5 mm or less, and further preferably 0.05 mm or more and 0.2 mm or less.
  • the impact absorbing sheet may be non-foamed or foamed as long as the density falls within the above range.
  • the foam may have closed cells, may have open cells, or may have both closed cells and open cells, but mainly has closed cells. It is preferable.
  • the closed cell ratio of the impact absorbing sheet is preferably 60% or more and 100% or less, more preferably 70% or more and 100% or less, and further preferably 80% or more and 100% or less.
  • the closed cell ratio can be determined according to, for example, JIS K7138 (2006).
  • the impact-absorbing sheet of the present invention has a relatively high density. Therefore, even a foamed body has a low foaming ratio and becomes finely foamed.
  • the impact-absorbing sheet may be a crosslinked body or a non-crosslinked body. However, when the impact absorbing sheet is a foam, it is preferably a crosslinked body.
  • the gel fraction indicating the degree of crosslinking of the impact absorbing sheet is preferably 10% by mass or more and 70% by mass or less, and more preferably 20% by mass or more and 60% by mass or less.
  • the gel fraction is measured by the following method. A test piece (test piece mass A (mg)) was cut out from the shock-absorbing sheet so as to have a mass of about 50 mg, and the test piece was immersed in 30 cm 3 of xylene at 105 ° C. and allowed to stand for 24 hours, and then 200 mesh.
  • the impact absorbing sheet of the present invention preferably has an impact absorption rate of 50% or more.
  • an impact absorption rate is measured by the method described in the Example mentioned later.
  • the impact-absorbing sheet is obtained by adding various additives, which will be described later, to the resin component as necessary.
  • the resin component constituting the shock absorbing sheet preferably contains an elastomer.
  • an impact-absorbing sheet uses the resin (A) and liquid rubber (B) which are shown below as a resin component, and resin (A) is elastomer (A1). ) Is more preferable.
  • the resin (A) such as the elastomer (A1) a solid resin that does not exhibit fluidity under conditions of 23 ° C. and 1 atm (1.01 ⁇ 10 ⁇ 1 MPa) is used.
  • the resin (A) for example, one having a storage elastic modulus higher than the storage elastic modulus of the shock absorbing sheet is used.
  • the resin (A) such as the elastomer (A1) preferably has a storage elastic modulus of 5.0 ⁇ 10 5 Pa or more and 1.0 ⁇ 10 8 Pa or less, more preferably storage elasticity. Those having a rate of 1.0 ⁇ 10 6 Pa to 5.0 ⁇ 10 7 Pa are used.
  • the storage elastic modulus was measured when the resin (A) was made into a sheet having a thickness of 150 ⁇ m, and details of the measurement method are as shown in the examples described later.
  • the resin (A) has an MFR (230 ° C., 21.2 N) of preferably 2 g / 10 min to 30 g / 10 min, more preferably 4 g / 10 min to 20 g / 10 min, and more preferably 6 g / 10 min to 15 g. / 10 min or less is more preferable.
  • the MFR is measured in accordance with JIS K 7210.
  • the content of the resin (A) is preferably 30% by mass or more and 90% by mass or less, more preferably 35% by mass or more and 80% by mass or less, and further preferably 40% by mass or more and 70% by mass or less, based on the total amount of the shock absorbing sheet.
  • a styrene thermoplastic elastomer, an olefin elastomer, a vinyl chloride elastomer, a urethane elastomer, a polyvinyl butyral resin, a polyvinyl alcohol resin, and the like can be used, and among them, a styrene thermoplastic elastomer is preferable.
  • thermoplastic elastomer examples include styrene-conjugated diene copolymers and hydrogenated products thereof.
  • the styrenic thermoplastic elastomer may be, for example, a random copolymer or a block copolymer in which each block constitutes either a hard segment or a soft segment. preferable.
  • the hard segment or the soft segment may be configured by randomly copolymerizing two or more components.
  • conjugated dienes include isoprene and butadiene.
  • the styrene content is preferably 5% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less.
  • the styrene-conjugated diene copolymer has a polystyrene block as a hard segment (X) at the molecular end, and a small amount of styrene is randomly copolymerized with the conjugated diene polymer block or conjugated diene as a soft segment (Y). And those having a styrene-conjugated diene random copolymer block.
  • the said small amount of styrene is a case where it is 20 mol% or less of the conjugated diene in a soft segment, for example. Examples of structures that can be adopted include the following.
  • the styrene-conjugated diene copolymer is preferably one having a structure of XYX.
  • the styrene-conjugated diene copolymer include a styrene content in the copolymer of 5% by mass to 20% by mass and a styrene content constituting the hard segment (X). What is 3 mass% or more and 15 mass% or less with respect to the whole coalescence is mentioned.
  • the styrene content in the segment is preferably 10% by mass or less based on the entire copolymer.
  • Such a styrene-conjugated diene copolymer is preferably a hydrogenated product.
  • the conjugated diene is preferably butadiene.
  • such a styrene-conjugated diene copolymer may be a styrene-ethylene-butylene-styrene block copolymer (SEBS).
  • SEBS styrene-ethylene-butylene-styrene block copolymer
  • Specific examples of the hydrogenated product of the styrene-conjugated diene elastomer described above include trade names “Dynalon 1320P” and “Dynalon 1321P” manufactured by JSR Corporation.
  • styrene-conjugated diene copolymer is a styrene-isoprene-styrene polymer (SIS) in which the blocks at both ends are made of polystyrene and the intermediate block is made of isoprene.
  • SIS styrene-isoprene-styrene polymer
  • the resin (A) described above may be used alone or in combination of two or more.
  • the impact-absorbing sheet preferably contains liquid rubber (B) in addition to the resin (A), and it is more preferable to use a styrene-based thermoplastic elastomer and liquid rubber (B) in combination.
  • the liquid rubber (B) has fluidity under the conditions of 20 ° C. and 1 atm (1.01 ⁇ 10 ⁇ 1 MPa) and becomes liquid.
  • the liquid rubber (B) has a viscosity at 38 ° C. of preferably 5 Pa ⁇ s to 1500 Pa ⁇ s, more preferably 10 Pa ⁇ s to 1300 Pa ⁇ s.
  • the viscosity is a value measured with a B-type rotational viscometer at a rotational speed of 100 rpm.
  • liquid rubber (B) examples include liquid acrylonitrile-butadiene rubber, liquid hydrogenated acrylonitrile-butadiene rubber, liquid carboxylated acrylonitrile-butadiene rubber, liquid acrylonitrile-butadiene-isoprene rubber, liquid acrylonitrile-isoprene.
  • Liquid acrylonitrile rubbers such as rubber and liquid terpolymers of acrylonitrile, butadiene and functional monomers having anti-aging function, etc., liquid chloroprene rubber, liquid isoprene rubber, liquid butyl rubber, liquid butadiene rubber, liquid ethylene-propylene -Diene rubber, liquid ethylene-propylene rubber, liquid natural rubber and the like.
  • liquid rubber (B) when the resin (A) is a styrene-based thermoplastic elastomer, it is preferable to use liquid isoprene rubber from the viewpoint of compatibility, storage elastic modulus, tan ⁇ , and the like.
  • the impact absorbing sheet may contain a process oil (C) in addition to the resin (A) and the liquid rubber (B).
  • a process oil (C) in addition to the resin (A) and the liquid rubber (B).
  • the storage modulus of the impact-absorbing sheet can be set to a suitable value and the moldability and the like can be improved.
  • the procell oil (C) include mineral oil such as paraffin oil, vegetable oil, and the like. Among these, paraffin oil is preferable.
  • a process oil for example, an oil-extended elastomer obtained by adding a process oil to a resin (A) such as an elastomer (A1) in advance may be used.
  • the process oil (C) preferably has a viscosity at 40 ° C. of 0.01 Pa ⁇ s to 1.0 Pa ⁇ s, more preferably 0.02 Pa ⁇ s to 0.5 Pa ⁇ s.
  • Process oil (C) may be used individually by 1 type, and may use 2 or more types together.
  • the total content of the liquid rubber (B) and the process oil (C) is preferably 10 parts by mass or more and 130 parts by mass or less with respect to 100 parts by mass of the resin (A) described above. 40 parts by mass or more and 120 parts by mass or less are more preferable, and 70 parts by mass or more and 110 parts by mass or less are more preferable.
  • an impact-absorbing sheet may contain (C) component and does not need to contain it.
  • the ratio (C / B) of the content of the process oil (C) to the content of the liquid rubber (B) is preferably 0.1 or more and 1.5 or less, 0.3 or more and 1.3 or less are more preferable, and 0.5 or more and 1.1 or less are still more preferable.
  • the shock absorbing sheet preferably contains an antioxidant.
  • the antioxidant include phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, and amine-based antioxidants.
  • phenolic antioxidants include 2,6-di-tert-butyl-p-cresol, n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2- tert-Butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate] methane and the like.
  • sulfur-based antioxidants examples include dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythrityl tetrakis (3-lauryl thiopropionate), and the like. .
  • An antioxidant may be used individually by 1 type and may use 2 or more types together.
  • the antioxidant is preferably 0.1 parts by mass or more and 2.0 parts by mass or less with respect to 100 parts by mass in total of the contents of the resin (A), the liquid rubber (B), and the process oil (C) described above. 0.2 parts by mass or more and 1.5 parts by mass or less are more preferable.
  • the impact absorbing sheet includes metal damage inhibitors, antistatic agents, stabilizers, nucleating agents, crosslinking agents, crosslinking aids, pigments, halogen-based, phosphorus-based flame retardants, and fillers.
  • Other additives such as these may be contained within a range not impairing the object of the present invention.
  • the impact-absorbing sheet of the present invention is a mixture of the resin (A), the liquid rubber (B), the process oil (C) blended as necessary, the antioxidant, and other additives. Then, it can be obtained by molding into a sheet shape. Specifically, each component is supplied to an extruder such as a single-screw extruder or a twin-screw extruder, melted, kneaded, and extruded by extrusion or the like to obtain a sheet-like resin composition. Although it is possible, the sheet-like resin composition can be used as an impact absorbing sheet.
  • the resin composition may appropriately perform either one or both of crosslinking and foaming.
  • the foaming of the resin composition is performed by, for example, mixing a thermal decomposable foaming agent together with the above components in the resin composition, heating the sheet-shaped resin composition to a temperature higher than the decomposition temperature of the pyrolyzable foaming agent, It is preferable to foam the sheet-shaped resin composition by thermally decomposing the decomposable foaming agent.
  • the pyrolytic foaming agent one having a decomposition temperature higher than the melting temperature of the resin can be used.
  • an organic or inorganic chemical foaming agent having a decomposition temperature of 160 ° C. or higher and 270 ° C. or lower can be used.
  • Organic foaming agents include azodicarbonamide, azodicarboxylic acid metal salts (such as barium azodicarboxylate), azo compounds such as azobisisobutyronitrile, nitroso compounds such as N, N′-dinitrosopentamethylenetetramine, And hydrazine derivatives such as hydrazodicarbonamide, 4,4′-oxybis (benzenesulfonylhydrazide) and toluenesulfonylhydrazide, and semicarbazide compounds such as toluenesulfonyl semicarbazide.
  • azodicarbonamide azodicarboxylic acid metal salts (such as barium azodicarboxylate)
  • azo compounds such as azobisisobutyronitrile
  • nitroso compounds such as N, N′-dinitrosopentamethylenetetramine
  • hydrazine derivatives such as hydrazodicarbonamide, 4,4′
  • the inorganic foaming agent examples include ammonium acid, sodium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, anhydrous monosodium citrate, and the like.
  • azo compounds and nitroso compounds are preferable from the viewpoint of obtaining fine bubbles, and from the viewpoints of economy and safety, and azodicarbonamide, azobisisobutyronitrile, N, N′-dinitrosopentamethylene. Tetramine is more preferred, and azodicarbonamide is still more preferred.
  • These pyrolytic foaming agents can be used alone or in combination of two or more. Even when the shock absorbing sheet is foamed, it is slightly foamed as described above.
  • the amount of the pyrolytic foaming agent is small.
  • the blending amount of the pyrolytic foaming agent in the resin composition is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass in total of the components (A) to (C). More preferably, it is 3 parts by mass or more and 3.0 parts by mass or less.
  • a decomposition temperature adjusting agent such as zinc oxide, zinc stearate or urea may be added to the resin composition.
  • the decomposition temperature adjusting agent is used in an amount of, for example, about 0.01 to 5 parts by mass with respect to 100 parts by mass in total of the above components (A) to (C) in order to adjust the surface condition of the heating equipment and foam. can do.
  • the foaming may be performed by means other than the above-described pyrolytic foaming agent, for example, by physical foaming.
  • a gas for forming bubbles instead of using the pyrolytic foaming agent.
  • a high-pressure inert gas is preferably used.
  • the inert gas include carbon dioxide, nitrogen gas, air, butane gas, and carbon dioxide is preferable. These gases may be used alone or in combination of two or more.
  • the inert gas is preferably impregnated into the resin composition in a supercritical state or a subcritical state.
  • the foaming in the present invention is not limited to the above-described chemical foaming and physical foaming, but includes foaming performed by other means for containing bubbles in the impact absorbing sheet.
  • hollow particles may be contained in the shock absorbing sheet.
  • the hollow particles include inorganic hollow particles and organic hollow particles.
  • the inorganic hollow particles include alumina bubbles, glass microballoons, shirasu balloons, fly ash balloons, kanamite, obsidian perlite, diamond balloons, and inorganic microcapsules.
  • organic hollow particles hollow particles made of polyvinylidene chloride resin such as phenol resin microballoons, Saran microspheres (trade name: manufactured by Dow), hollow particles made of epoxy resins such as ecospheres, clecas spheres, Carbon hollow particles, such as other carbon spheres, etc. are mentioned.
  • the crosslinking of the resin composition may be performed when the impact absorbing sheet is a non-foamed body or a foamed body, but is preferably performed when the impact absorbing sheet is a foamed body.
  • Crosslinking of the resin composition may be performed on the resin composition formed into a sheet shape, but in the case of a foam, it may be performed on the sheet-shaped resin composition before foaming.
  • Crosslinking is preferably performed by irradiating the resin composition formed into a sheet shape with ionizing radiation. Examples of ionizing radiation include ⁇ -rays, ⁇ -rays, ⁇ -rays, and electron beams, and electron beams are more preferable.
  • the irradiation dose of ionizing radiation is preferably 0.5 Mrad to 10 Mrad, and more preferably 1 Mrad to 8 Mrad.
  • Crosslinking may be performed by a method in which a crosslinking agent such as an organic peroxide is previously blended in the resin composition and the organic peroxide is decomposed by heating the resin composition.
  • a crosslinking agent such as an organic peroxide
  • organic peroxides include 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, and the like.
  • the impact absorbing sheet may be appropriately stretched.
  • the stretching may be performed while foaming the resin composition, or may be performed after foaming the resin composition.
  • the foam when the foam is stretched after foaming the resin sheet, the foam may be stretched while maintaining the molten state during foaming without cooling the foam. After cooling the foam, the foam may be stretched again by heating it to a molten or softened state. Stretching may be performed in one or both of the MD direction and the TD direction.
  • the stretching is preferably performed on the sheet-like resin composition, but when it is crosslinked, it may be performed after crosslinking.
  • the shock absorbing sheet of the present invention is used for various electronic devices, preferably portable electronic devices such as notebook personal computers, mobile phones, electronic paper, digital cameras, video cameras and the like. More specifically, it is used as an impact absorbing sheet for a display device provided in these electronic devices.
  • the display device include an organic EL display device and a liquid crystal display device, and an organic EL display device is preferable. Further, it is preferable that the display device, particularly the organic EL display device, be a flexible display.
  • An organic EL display device is flexible by forming an organic EL element including both electrodes, a light emitting layer formed between the electrodes, and a sealing material for sealing the light emitting layer on a film substrate. It can be a display.
  • the impact absorbing sheet When used in a display device, the impact absorbing sheet is disposed on the back side of various display devices and absorbs impacts applied to the display device. More specifically, the shock absorbing sheet is placed on, for example, a housing of an electronic device and is disposed between the housing and the display device. In addition, the shock absorbing sheet is usually compressed and arranged between a component constituting an electronic device such as a housing and the display device. Since the impact absorbing sheet of the present invention has high impact absorbing performance even if it is thin, it is possible to appropriately prevent damage to the display device while reducing the thickness of the electronic device. In addition, even when a relatively large impact is applied locally, the impact-absorbing sheet can absorb the impact appropriately, so that display defects such as glass breakage and flexible displays can be avoided. It becomes possible to prevent appropriately.
  • the shock absorbing sheet may be used by appropriately laminating a resin sheet on one side and both sides thereof.
  • the resin used for the resin sheet include polyolefin resins such as polyethylene and polypropylene, and thermoplastic resins such as polyethylene terephthalate resin.
  • Each resin sheet is preferably thinner than the impact absorbing sheet, and has a thickness of, for example, 10 ⁇ m to 300 ⁇ m, preferably 10 ⁇ m to 200 ⁇ m.
  • the resin sheet may be bonded to the shock absorbing sheet by thermocompression bonding, or may be bonded to the shock absorbing sheet using an adhesive or the like.
  • the impact absorbing sheet may be used as an adhesive tape by providing an adhesive material on one side or both sides.
  • the pressure-sensitive adhesive material only needs to have at least a pressure-sensitive adhesive layer, and may be composed of a single pressure-sensitive adhesive layer laminated on the surface of the shock-absorbing sheet, or a double-sided pressure-sensitive adhesive stuck to the surface of the shock-absorbing sheet.
  • it may be a sheet, it is preferably a pressure-sensitive adhesive layer alone.
  • a double-sided adhesive sheet is provided with a base material and the adhesive layer provided in both surfaces of the base material.
  • the double-sided pressure-sensitive adhesive sheet is used for bonding one pressure-sensitive adhesive layer to the shock absorbing sheet and bonding the other pressure-sensitive adhesive layer to other components.
  • an adhesive which comprises an adhesive layer For example, an acrylic adhesive, a urethane type adhesive, a rubber-type adhesive etc. can be used.
  • the thickness of the adhesive material is preferably 5 ⁇ m or more and 200 ⁇ m or less, and more preferably 7 ⁇ m or more and 150 ⁇ m or less.
  • a release sheet such as a release paper may be further bonded onto the adhesive material, and the adhesive layer may be protected by the release paper before use.
  • each physical property and performance of the shock absorbing sheet are evaluated by the following methods.
  • the storage elastic modulus and tan ⁇ at 23 ° C. were determined under the condition of min.
  • the sample size was 40 mm in length (however, the distance between grips was 25 mm) and 5 mm in width.
  • the density of the shock absorbing sheet is an apparent density value measured according to JIS K6767.
  • ⁇ Shock absorption test> A shock absorbing sheet (50 mm square) was placed on the center of an acrylic plate (100 mm square, thickness 10 mm), and an acceleration sensor was attached to the surface opposite to the surface of the acrylic plate on which the shock absorbing sheet was placed.
  • the acrylic plate has four corners fixed to a pedestal with bolts having a length of 35 mm, and the upper surface of the acrylic plate is held at a position 25 mm from the pedestal surface.
  • TPS1 Styrenic thermoplastic elastomer
  • MFR 230 ° C., 21.2 N
  • storage elastic modulus at 23 ° C. 1.7 ⁇ 10 6 Pa, 23 ° C.
  • Tan ⁇ 0.11 and styrene content 10% by mass
  • Liquid isoprene rubber trade name “Kuraprene LIR-290”, manufactured by Kuraray Co., Ltd., viscosity at 38 ° C .: 1200 Pa ⁇ s
  • Process oil PO
  • TPS2 Styrenic thermoplastic elastomer
  • Styrenic thermoplastic elastomer TPS3: Trade name “Arneston CJ103”, Kuraray Plastics Co., Ltd.
  • PE polyethylene resin
  • PE Polyvinyl butyral resin
  • antioxidant phenolic antioxidant
  • ADEKA thermal decomposition type foaming agent azodicarbonamide
  • Example 1 50 parts by mass of styrene thermoplastic elastomer (TPS1) as resin (A), 50 parts by mass of liquid isoprene rubber (IR) as liquid rubber (B), and 1 part by mass of antioxidant are kneaded at 160 ° C.
  • TPS1 styrene thermoplastic elastomer
  • IR liquid isoprene rubber
  • antioxidant 1 part by mass of antioxidant
  • Example 2 50 parts by mass of styrene-based thermoplastic elastomer (TPS1) as resin (A), 25 parts by mass of liquid isoprene rubber (IR) as liquid rubber (B), and paraffin oil (PO) 25 as process oil (C)
  • TPS1 styrene-based thermoplastic elastomer
  • IR liquid isoprene rubber
  • PO paraffin oil
  • C process oil
  • Example 3 The same operation as in Example 1 was carried out except that both surfaces of the sheet-shaped resin composition were crosslinked by irradiation with an electron beam of 800 kV at an acceleration voltage of 4.0 Mrad.
  • Example 4 The same operation as in Example 2 was performed except that both surfaces of the sheet-shaped resin composition were crosslinked by irradiation with an electron beam of 800 kV at an acceleration voltage of 4.0 Mrad.
  • Example 5 In addition to the components (A) and (B) and the antioxidant, in the same manner as in Example 3, except that 1 part by mass of azodicarbonamide (ADCA) as a pyrolytic foaming agent was added. The resin composition was molded and then crosslinked. Then, the cross-linked sheet-shaped resin composition is passed through a heating furnace at 250 ° C. to be foamed and stretched in the MD and TD directions to obtain a cross-linked foam having a thickness of 0.15 mm. Was used as an impact absorbing sheet.
  • ADCA azodicarbonamide
  • Example 6 In the same manner as in Example 4 except that 1 part by mass of azodicarbonamide (ADCA) as a pyrolytic foaming agent was added in addition to the components (A), (B) and (C) and the antioxidant. Next, a sheet-like resin composition was molded and then crosslinked. Then, the cross-linked sheet-shaped resin composition is passed through a heating furnace at 250 ° C. to be foamed and stretched in the MD and TD directions to obtain a cross-linked foam having a thickness of 0.15 mm. Was used as an impact absorbing sheet. [Example 7] The same procedure as in Example 5 was performed except that 0.8 part by mass of azodicarbonamide (ADCA) as a pyrolytic foaming agent was added.
  • ADCA 0.8 part by mass of azodicarbonamide
  • the impact absorption rate could be increased to 50% or more.
  • the shock absorption rate is less than 50%, and the shock absorption performance is not sufficient. It was.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Laminated Bodies (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

La présente invention concerne une feuille d'amortissement de chocs qui présente un module élastique de conservation de 1,0×105 <sp /> à 2,5×107 Pa à 23 oC, une tanδ supérieure ou égale à 0,3 à 23 oC, et une masse volumique supérieure ou égale à 600 kg/m3. Selon la présente invention, il est possible de fournir : une feuille d'amortissement de chocs qui présente d'excellentes propriétés d'amortissement de chocs, de sorte que même si, par exemple, la feuille d'amortissement de chocs est mince, ses propriétés d'amortissement de chocs contre un impact relativement grand et appliqué localement sont bonnes.
PCT/JP2018/000380 2017-01-11 2018-01-10 Feuille d'amortissement de chocs WO2018131619A1 (fr)

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CN201880006432.XA CN110191913A (zh) 2017-01-11 2018-01-10 冲击吸收片
KR1020197020167A KR20190104540A (ko) 2017-01-11 2018-01-10 충격 흡수 시트

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CN109943005A (zh) * 2018-08-21 2019-06-28 广西沙沙岛实业有限公司 弹性颗粒及其制备方法和应用
JP2020037602A (ja) * 2018-08-31 2020-03-12 積水化学工業株式会社 樹脂発泡体シート
CN112585527A (zh) * 2018-08-28 2021-03-30 富士胶片株式会社 液晶面板及图像显示装置
KR20230041697A (ko) 2020-07-21 2023-03-24 파나소닉 아이피 매니지먼트 가부시키가이샤 충격 흡수 시트

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WO2001074964A1 (fr) * 2000-04-05 2001-10-11 Kaneka Corporation Composition amortissant les vibrations
JP2007070595A (ja) * 2004-12-21 2007-03-22 Tokai Rubber Ind Ltd 高減衰エラストマー組成物およびそれによって得られた制震ダンパー
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Publication number Priority date Publication date Assignee Title
CN109943005A (zh) * 2018-08-21 2019-06-28 广西沙沙岛实业有限公司 弹性颗粒及其制备方法和应用
CN109943005B (zh) * 2018-08-21 2020-05-26 广西沙沙岛实业有限公司 弹性颗粒及其制备方法和应用
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CN112585527A (zh) * 2018-08-28 2021-03-30 富士胶片株式会社 液晶面板及图像显示装置
JP2020037602A (ja) * 2018-08-31 2020-03-12 積水化学工業株式会社 樹脂発泡体シート
KR20230041697A (ko) 2020-07-21 2023-03-24 파나소닉 아이피 매니지먼트 가부시키가이샤 충격 흡수 시트

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CN110191913A (zh) 2019-08-30
KR20190104540A (ko) 2019-09-10
JPWO2018131619A1 (ja) 2019-11-07

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