KR102218808B1 - Resin foam composite - Google Patents

Abstract

A flexible resin foam composite that can be used for an extremely narrow design gap is provided with the thinning of electronic devices. A resin foam composite in which a resin foam layer and an adhesive layer are laminated, the apparent density of the resin foam layer is 0.03 to 0.30 g/cm ³ , the compressive stress at 50% compression is 5.0 N/cm ² or less, and the thickness of the adhesive layer Is 0.0005mm to 0.06mm, and the total thickness of the resin foam composite is 0.35mm or less. It is preferable that the ratio of the thickness of the resin foam layer and the thickness of the pressure-sensitive adhesive layer (thickness of the resin foam layer/thickness of the adhesive layer) is 2.1 or more.

Description

Resin foam composite {RESIN FOAM COMPOSITE}

The present invention relates to a resin foam composite in which a resin foam layer and an adhesive layer are laminated.

The resin foam is used as a sealing material or a cushioning material for electronic devices such as mobile phones, smart phones, and tablet PCs. In particular, in order to facilitate the alignment of the adhesive layer during the bonding operation, a resin foam composite provided with an adhesive layer is suitably used. In recent years, with the miniaturization of electronic devices and the enlargement of the screen, the area of the resin foam composite used as a sealing material or a cushioning material has become smaller, and the resin foam composite is required to have sufficient flexibility to exhibit sufficient sealing and buffering properties even in a small area. Has become. In addition, in electronic devices, thinning is also progressing, and thinning is also required for the resin foam composite.

As a thin resin foam, a foam sheet obtained by a method of performing compression treatment or stretching treatment during or after foaming, or a method of applying coating treatment after foaming is known (see, for example, Patent Document 1 and Patent Document 2). . However, the foam sheet has a problem that it is difficult to increase the expansion ratio, and the repulsive force when compressed by 25% (repulsive stress at 25% compression) exceeds 3N/cm ² , etc. There was this big problem.

In addition, with the recent thinning of portable devices, the design gap (gap, gap) in which the resin foam is used is very narrow (e.g., a gap of 0.1 mm or less), and the resin foam composite is 50% or more in consideration of design errors. It is not uncommon to be compressed and used. However, if the resin foam composite having a large repulsive force when compressed in the very narrow design gap of such a display device is used, due to the high repulsive force, for example, display unevenness in the liquid crystal of the display unit may occur, causing display defects. there was.

Further, it is considered to reduce the repulsive force by lowering the compressibility by using a thin resin foam. However, as described above, in the case of a resin foam composite in which an adhesive layer is provided on a resin foam, since the adhesive layer itself is not compressed, when a thick adhesive layer is used, the repulsive force is increased and display unevenness may occur.

Japanese Patent Publication No. 2009-190195 Japanese Patent Laid-Open No. 2010-1407

Accordingly, it is an object of the present invention to provide a flexible resin foam composite that can be used with respect to a design gap that is very narrow along with the thinning of electronic devices. In addition, it is to provide a resin foam composite that can be easily aligned during the bonding operation.

The present inventors, as a result of earnestly examining in order to achieve the above object, use a specific resin foam layer, and by setting the thickness of the resin foam composite and the thickness of the pressure-sensitive adhesive layer to predetermined, the repulsive force is suppressed and alignment is simplified. It has been discovered that a possible resin foam composite can be obtained. The present invention was completed based on these findings.

That is, the present invention is a resin foam composite in which a resin foam layer and an adhesive layer are laminated, the apparent density of the resin foam layer is 0.03 to 0.30 g/cm ³ and the compressive stress at 50% compression is 5.0 N/cm ² Hereinafter, the thickness of the pressure-sensitive adhesive layer is 0.0005 mm to 0.06 mm, and the total thickness of the resin foam composite is 0.35 mm or less.

In particular, the ratio of the thickness of the resin foam layer to the thickness of the pressure-sensitive adhesive layer (thickness of the resin foam layer/thickness of the adhesive layer) is preferably 2.1 or more.

In addition, the pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive layer.

Moreover, in the said resin foam composite, it is preferable that the resin which comprises the said resin foam layer is a thermoplastic resin, and it is still more preferable that it is a polyolefin resin.

Further, in the resin foam composite, it is preferable to have a surface layer formed by heat melting treatment on at least one surface of the resin foam layer.

Further, in the resin foam composite, it is preferable that the resin foam layer is formed through a step of depressurizing after impregnating the resin with a high-pressure gas.

Further, in the resin foam composite, the gas is preferably an inert gas, and more preferably carbon dioxide.

Further, in the resin foam composite, it is more preferable that the high-pressure gas is in a supercritical state.

Further, in the resin foam composite, it is preferable that the resin foam layer has a closed cell structure or a semi-continuous semi-independent cell structure.

Since the resin foam composite of the present invention has the above configuration, it is flexible and can suppress an increase in repulsive force when compressed. For this reason, even if the resin foam composite of the present invention is used for, for example, a very narrow gap in a liquid crystal display device, it does not cause uneven display or poor display. In addition, the resin foam composite of the present invention can be easily aligned, particularly during bonding.

1 is a schematic diagram of a continuous slicing device.
2 is a schematic diagram of a continuous processing apparatus having a heating roll.

The resin foam composite of the present invention has at least a configuration in which a resin foam layer and an adhesive layer (pressure sensitive adhesive layer) are laminated.

[Resin foam layer]

The resin foam layer in the resin foam composite of the present invention is a layer made of a resin foam. The resin foam is obtained by foaming a resin composition.

In the resin foam layer, the apparent density of ^{0.03g / cm 3 ~0.30g / cm 3} . In the resin foam layer, since the apparent density is 0.03 g/cm ³ or more, strength can be ensured, and since the apparent density is 0.30 g/cm ³ or less, good flexibility can be obtained. The apparent density of the foamed resin layer is preferably from ^{0.04g / cm 3 ~0.25g / cm 3} , more preferably ^{0.045g / cm 3 ~0.20g / cm 3} . The apparent density of the resin foam layer can be controlled by adjusting the expansion ratio by the amount or pressure of the foaming agent impregnated into the resin composition.

In the resin foam layer, the compressive stress at 50% compression is 5.0 N/cm ² or less. In the resin foam layer, since the compressive stress at 50% compression is 5.0 N/cm ² or less, good flexibility is obtained, and the repulsive force when compressed can be reduced. The compressive stress at 50% compression of the resin foam layer is preferably 4.0 N/cm ² or less, and more preferably 3.0 N/cm ² or less. Moreover, it is preferable that it is 0.1 N/cm ² or more, and it is more preferable that it is 0.2 N/cm ² or more. The compressive stress at the time of 50% compression of the resin foam layer can be controlled by adjusting the expansion ratio and the degree of softness due to the temperature at the time of expansion. The soft grape degree refers to the degree to which the closed cell structure becomes continuous (soft saturation) when the resin composition is foamed.

On the other hand, the compressive stress at the time of 50% compression is based on JIS K 6767, the stress (N) when compressed by 50% of the initial thickness in the thickness direction of the resin foam layer is measured, and the stress is measured in a unit area ( It is obtained by converting to per cm ² ).

The resin foam layer in the resin foam composite of the present invention is obtained by foaming the resin composition as described above. The resin foam layer is not particularly limited, but is preferably formed by foaming a thermoplastic resin composition containing a thermoplastic resin. Especially, it is preferable to form by foaming a polyolefin resin composition containing a polyolefin resin. That is, it is preferable that the said resin foam layer in the resin foam composite of this invention is a polyolefin resin foam layer. On the other hand, the resin composition may contain other components and additives in addition to the resin. Further, the resin, the other components, the additives, and the like may be used alone or in combination of two or more.

On the other hand, the content of the resin in the resin composition is not particularly limited, but is preferably 50% by mass or more, and more preferably 60% by mass or more with respect to the total amount (100% by mass) of the resin composition.

The cell structure (cell structure) of the resin foam layer in the resin foam composite of the present invention is not particularly limited, but a closed cell structure, a semi-continuous semi-independent cell structure (a cell structure in which an independent cell structure and a continuous cell structure are mixed And the ratio is not particularly limited), more preferably a semi-continuous semi-independent cell structure. The proportion of the closed cell structure portion of the resin foam layer is not particularly limited, but from the viewpoint of flexibility, it is preferably 40% or less, more preferably 30% or less with respect to the total (100%) of the resin foam layer. . The cell structure can be controlled, for example, by controlling the expansion ratio by the amount or pressure of the foaming agent impregnated into the resin composition during foam molding.

The average cell diameter (average cell diameter) in the cell structure of the resin foam layer in the resin foam composite of the present invention is not particularly limited, but, for example, 10 μm to 150 μm is preferable, and 20 μm to 120 μm is more preferable. , 30 μm to 80 μm are more preferable. When the average cell diameter of the said resin foam layer is 10 micrometers or more, the impact absorption property (cushion property) becomes easy to improve. In addition, when the average cell diameter of the resin foam layer is 150 μm or less, it becomes a foam having a finer cell structure, so it becomes easier to use it in a minute gap, and the dustproof property is more easily improved.

The resin which is the material of the resin foam layer in the resin foam composite of the present invention is not particularly limited, but a thermoplastic resin (thermoplastic polymer) is preferable. That is, it is preferable that the resin foam layer in the resin foam composite of the present invention is obtained by foaming a thermoplastic resin composition containing at least a thermoplastic resin. The thermoplastic resin (thermoplastic polymer) that is a material of the resin foam layer is not particularly limited as long as it is a polymer exhibiting thermoplasticity and can be impregnated with high-pressure gas. Examples of such thermoplastic resins include polyolefin resins (details will be described later); Styrene resins such as polystyrene and acrylonitrile-butadiene-styrene copolymer (ABS resin); Polyamide resins such as 6-nylon, 66-nylon, and 12-nylon; Polyamideimide; Polyurethane; Polyimide; Polyetherimide; Acrylic resins such as polymethyl methacrylate; Polyvinyl chloride; Polyvinyl fluoride; Alkenyl aromatic resins; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonates such as bisphenol A polycarbonate; Polyacetal; Polyphenylene sulfide, etc. are mentioned. Thermoplastic resins can be used alone or in combination of two or more. On the other hand, when the thermoplastic resin is a copolymer, any type of a random copolymer or a block copolymer may be used.

The polyolefin-based resin is not particularly limited, but a polymer composed (formed) of an α-olefin as an essential monomer component, that is, a polymer having a constitutional unit derived from at least an α-olefin in the molecule (in one molecule). It is preferable to be. The polyolefin resin may be, for example, a polymer composed of only α-olefins or may be a polymer composed of monomer components other than α-olefins and α-olefins.

The polyolefin resin may be a homopolymer (homopolymer) or a copolymer (copolymer) containing two or more types of monomers. Further, when the polyolefin resin is a copolymer, a random copolymer or a block copolymer may be used. The polyolefin resin may be one type of polymer or a combination of two or more types of polymers.

The polyolefin resin is not particularly limited, but it is preferably a linear polyolefin from the viewpoint of obtaining a polyolefin resin foam having a high expansion ratio.

As the α-olefin, for example, an α-olefin having 2 to 8 carbon atoms (e.g., ethylene, propylene, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, heptene-1, octene-1 Etc.). Incidentally, the α-olefin may be used alone or in combination of two or more.

As a monomer component other than the said α-olefin, ethylenically unsaturated monomers, such as vinyl acetate, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, and vinyl alcohol, are mentioned, for example. Monomer components other than α-olefin may be used alone or in combination of two or more.

Examples of the polyolefin resin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene (propylene homopolymer), ethylene and propylene copolymer, ethylene and other α-olefin copolymers, and propylene. And copolymers of α-olefins other than propylene, copolymers of ethylene and propylene with ethylene and α-olefins other than propylene, and copolymers of propylene and ethylenically unsaturated monomers.

As the polyolefin resin, from the viewpoint of heat resistance, a polymer composed of propylene as an essential monomer component (polypropylene polymer), that is, a polymer having at least a structural unit derived from propylene is preferable. That is, examples of the polyolefin-based resin include polypropylene-based polymers such as polypropylene (propylene homopolymer), a copolymer of ethylene and propylene, and a copolymer of propylene and an α-olefin other than propylene. The α-olefins other than propylene may be used alone or in combination of two or more.

Although the content of the α-olefin is not particularly limited, for example, 0.1% by mass to 10% by mass is preferable, more preferably 1% by mass, based on the total amount (100% by mass) of the monomer components constituting the polyolefin resin. % To 5% by mass.

Further, the thermoplastic resin composition may contain "rubber and/or thermoplastic elastomer" as other components other than the thermoplastic resin.

Although it does not specifically limit as said rubber, For example, natural or synthetic rubbers, such as natural rubber, polyisobutylene, isoprene rubber, chloroprene rubber, butyl rubber, and nitrile butyl rubber, are mentioned. These rubbers may be used alone or in combination of two or more.

The thermoplastic elastomer is not particularly limited, but for example, thermoplastic olefins such as ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, polybutene, polyisobutylene, and chlorinated polyethylene. Elastomer; Thermoplastic styrene elastomers such as styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-isoprene-butadiene-styrene copolymer, and hydrogenated polymers thereof; Thermoplastic polyester elastomers; Thermoplastic polyurethane elastomers; And thermoplastic acrylic elastomers. The thermoplastic elastomer may be used alone or in combination of two or more.

The content of the ``rubber and/or thermoplastic elastomer'' in the thermoplastic resin composition is not particularly limited, but is preferably 0% by mass to 70% by mass, more preferably based on the total amount (100% by mass) of the thermoplastic resin composition. Is 20% by mass to 60% by weight, more preferably 20% by mass to 50% by weight.

In addition to the thermoplastic resin, the thermoplastic resin composition may contain “a mixture (composition) containing a rubber and/or a thermoplastic elastomer and a softener” as other components. Incidentally, the "mixture (composition) containing a rubber and/or thermoplastic elastomer and a softener" may contain an additive as necessary.

Examples of the ``mixture (composition) containing a rubber and/or thermoplastic elastomer and a softener'' include, for example, a mixture containing at least a rubber and a thermoplastic elastomer and a softener, a mixture containing at least a rubber and a softener, and a thermoplastic elastomer and a softener. And a mixture to be included. Among them, "a mixture comprising only a rubber and/or thermoplastic elastomer and a softener" is preferred.

Although it does not specifically limit as rubber in the said "mixture containing a rubber and/or a thermoplastic elastomer, and a softener", the said rubber exemplified as the rubber of the said "rubber and/or thermoplastic elastomer" is mentioned preferably. Incidentally, the rubber may be used alone or in combination of two or more.

In addition, the rubber and/or thermoplastic elastomer in the above ``mixture containing a rubber and/or thermoplastic elastomer and a softener'' is not particularly limited as long as it can be foamed. For example, a known and commonly used ``rubber and/or thermoplastic elastomer'' Can be mentioned. Among them, the thermoplastic elastomer exemplified as the thermoplastic elastomer of the "rubber and/or thermoplastic elastomer" is preferably mentioned. Incidentally, the thermoplastic elastomer may be used alone or in combination of two or more.

In particular, in the polyolefin resin composition using a polyolefin resin as a thermoplastic resin, as the ``rubber and/or thermoplastic elastomer'' in the ``mixture containing a rubber and/or thermoplastic elastomer and a softener'', an olefin elastomer is used. Preferred, and particularly preferably, is an olefin-based elastomer having a structure in which a polyolefin component and an olefin-based rubber component are micro-phase separated. As the olefin elastomer having a structure in which the polyolefin component and the olefin rubber component are microphase separated, an elastomer composed of polypropylene resin (PP) and ethylene-propylene rubber (EPM) or ethylene-propylene-diene rubber (EPDM) is preferable. Is illustrated. On the other hand, the mass ratio of the polyolefin component and the olefin-based rubber component is preferably a polyolefin component/olefin-based rubber = 90/10 to 10/90, and more preferably 80/20 to 20/80 from the viewpoint of compatibility. .

Although it does not specifically limit as said softener, The softener generally used for rubber products is mentioned preferably. By containing the said softener, processability and flexibility can be improved.

Specific examples of the softener include petroleum substances such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and petrolatum; Coal tar, such as coal tar and coal tar pitch; Fatty oils such as castor oil, linseed oil, rapeseed oil, soybean oil, and palm oil; Waxes such as sesame oil, beeswax, carnauba wax, and lanolin; Synthetic polymer substances such as petroleum resin, coumarone indene resin, and atactic polypropylene; Ester compounds such as dioctylphthalate, dioctyl adipate, and dioctyl sebacate; Microcrystalline wax, sub (Factis), liquid polybutadiene, modified liquid polybutadiene, liquid thiocol, liquid polyisoprene, liquid polybutene, liquid ethylene/α-olefin copolymer, etc. Can be lifted. Among them, paraffinic, naphthenic, aromatic mineral oils, liquid polyisoprene, liquid polybutene, and liquid ethylene/α-olefin-based copolymers are preferred, and more preferably liquid polyisoprene, liquid polybutene, and liquid It is an ethylene/α-olefin-based copolymer. In addition, the said softener may be used individually or in combination of 2 or more types.

The content of the softener in the ``mixture containing the rubber and/or thermoplastic elastomer and the softener'' is not particularly limited, but is preferably 1 part by mass to 200 parts by mass based on 100 parts by mass of the rubber and/or thermoplastic elastomer component, More preferably, it is 5 mass parts-100 mass parts, More preferably, it is 10 mass parts-50 mass parts. On the other hand, when the content of the softening agent is too large, dispersion failure may occur during kneading of the rubber and/or thermoplastic elastomer.

In the "mixture containing rubber and/or thermoplastic elastomer and softener", an additive may be added. Although it does not specifically limit as such an additive, For example, an anti-aging agent, a weathering agent, an ultraviolet absorber, a dispersing agent, a plasticizer, a carbon black, an antistatic agent, a surfactant, a tension modifier, a fluidity modifier, etc. are mentioned. On the other hand, such additives may be used alone or in combination of two or more.

The content of the additive in the ``mixture containing a rubber and/or thermoplastic elastomer and a softener'' is not particularly limited, but for example, 0.01 to 100 parts by mass per 100 parts by mass of the rubber and/or thermoplastic elastomer component It is preferred, more preferably 0.05 parts by mass to 50 parts by mass, still more preferably 0.1 parts by mass to 30 parts by mass. On the other hand, when the said content is 0.01 mass part or more, since it becomes easier to express the effect by adding an additive, it is preferable.

The melt flow rate (MFR) (230°C) of the above "mixture containing rubber and/or thermoplastic elastomer and softener" is not particularly limited, but from 3 g/10 min to 10 g/10 min in terms of obtaining good moldability Preferably, it is 4 g/10 minutes-9 g/10 minutes more preferably.

The ``JIS A hardness'' in the ``mixture containing a rubber and/or thermoplastic elastomer and a softener'' is not particularly limited, but is preferably 30° to 90°, and more preferably 40° to 85°. . When the said "JIS A hardness" is 30 degrees or more, it becomes easy to obtain a resin foam with a high foaming ratio, and it is preferable. Moreover, when the said "JIS A hardness" is 90 degrees or less, it becomes easy to obtain a flexible resin foam, and is preferable. In addition, "JIS A hardness" in this specification shall mean the hardness measured based on ISO 7619 (JIS K6253).

The resin composition, such as the thermoplastic resin composition, may contain an additive within a range that does not impair the effects of the present invention. Examples of the additives include bubble nucleating agents, crystal nucleating agents, plasticizers, lubricants, colorants (pigments, dyes, etc.), ultraviolet absorbers, antioxidants, anti-aging agents, fillers, reinforcing agents, antistatic agents, surfactants, tension modifiers, shrinkage inhibitors, fluidity Modifiers, clays, vulcanizing agents, surface treatment agents, flame retardants, etc. are mentioned. Meanwhile, the additives may be used alone or in combination of two or more.

From the viewpoint of obtaining a resin foam layer having a uniform and fine cell structure, it is preferable that a cell nucleating agent is contained in the resin composition. For example, if the foam nucleating agent is contained in the thermoplastic resin composition, since a resin foam having a uniform and fine cell structure can be easily obtained, it is preferable that the foam nucleating agent is contained in the thermoplastic resin composition.

Examples of the bubble nucleating agent include particles. Examples of the particles include talc, silica, alumina, zeolite, calcium carbonate, magnesium carbonate, barium sulfate, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, mica, clay such as montmorillonite, carbon particles, glass fibers, carbon tubes. And the like. On the other hand, particles may be used alone or in combination of two or more.

In resin compositions such as the thermoplastic resin composition, the content of the bubble nucleating agent is not particularly limited. For example, when the thermoplastic resin composition is a resin composition containing the thermoplastic resin and ``a mixture containing a rubber and/or a thermoplastic elastomer, and a softener'', the content of the bubble nucleating agent in such a resin composition is not particularly limited. , 0.5 to 125 parts by mass per 100 parts by mass of the total amount of the thermoplastic resin and the ``mixture (composition) containing a rubber and/or thermoplastic elastomer and a softener (composition)'' (hereinafter sometimes referred to as ``total amount of resin components'') The mass part is preferable, More preferably, it is 1 mass part-120 mass part.

The average particle diameter (particle diameter) of the particles is not particularly limited, but is preferably 0.1 μm to 20 μm. If the average particle diameter is less than 0.1 μm, it may not function as a foam nucleating agent, while if the particle diameter exceeds 20 μm, it may cause degassing during foam molding.

When the flame retardant is contained in the resin composition, the resin foam layer becomes flame retardant, and can be used in applications requiring flame retardancy such as electric or electronic device applications. For this reason, a flame retardant may be contained in resin compositions, such as the said thermoplastic resin composition.

The flame retardant may be in a powder form or may have a form other than a powder form. As a powdery flame retardant, an inorganic flame retardant is preferable. Examples of the inorganic flame retardant include a bromine flame retardant, a chlorine flame retardant, a phosphorus flame retardant, an antimony flame retardant, and a non-halogen-nonantimony inorganic flame retardant. Here, the chlorine-based flame retardant or bromine-based flame retardant generates a gas component that is harmful to the human body and corrosive to equipment during combustion, and the phosphorus-based flame retardant and antimony-based flame retardant have problems such as harmfulness and explosive properties. For this reason, as the inorganic flame retardant, a non-halogen-non-antimony inorganic flame retardant is preferable. Examples of the non-halogen-non-antimony-based inorganic flame retardant include hydrated metal compounds such as aluminum hydroxide, magnesium hydroxide, magnesium oxide/nickel oxide hydrate, and magnesium oxide/zinc oxide hydrate. In addition, the hydrated metal oxide may be surface-treated. On the other hand, flame retardants may be used alone or in combination of two or more.

It is preferable that the flame retardant also has a function as a cell nucleating agent from the viewpoint of obtaining a resin foam layer having flame retardancy and a high expansion ratio. As a flame retardant having a function as a bubble nucleating agent, magnesium hydroxide, aluminum hydroxide, etc. are mentioned, for example.

In resin compositions such as the thermoplastic resin composition, the content of the flame retardant is not particularly limited. For example, the content of the flame retardant in the thermoplastic resin composition is not particularly limited, but is preferably 30 parts by mass to 150 parts by mass, more preferably 60 parts by mass to 120 parts by mass based on 100 parts by mass of the total amount of the resin component. to be. If the amount of the flame retardant is too small, the flame-retardant effect becomes small, and if it is too large, it becomes difficult to obtain a foam with high foaming.

Further, when the lubricant is contained in the resin composition, the fluidity of the resin composition can be improved, and thermal deterioration can be suppressed. For this reason, a lubricant may be contained in a resin composition such as the thermoplastic resin composition.

Although it does not specifically limit as said lubricant, For example, hydrocarbon-type lubricants, such as liquid paraffin, paraffin wax, micro wax, and polyethylene wax; Fatty acid lubricants such as stearic acid, behenic acid and 12-hydroxystearic acid; Ester-based lubricants such as butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, hydrogenated castor oil, stearyl stearate, and the like. In addition, lubricants may be used alone or in combination of two or more.

In resin compositions such as the thermoplastic resin composition, the content of the lubricant is not particularly limited. For example, when the thermoplastic resin composition is a resin composition containing the thermoplastic resin and ``a mixture containing a rubber and/or a thermoplastic elastomer, and a softener'', the content of the lubricant in such a resin composition is not particularly limited, With respect to 100 parts by mass of the total amount of the resin component, 0.1 to 10 parts by mass is preferable, and more preferably 0.5 to 5 parts by mass. When the addition amount exceeds 10 parts by mass, the fluidity becomes too high, and the foaming ratio may decrease. In addition, if it is less than 0.1 parts by mass, the fluidity cannot be improved, the stretchability at the time of foaming decreases, and the foaming ratio may decrease.

Further, the anti-shrinkage agent has an effect of effectively suppressing the permeation of the foaming agent gas by forming a molecular film on the surface of the foam film of the foam. For this reason, from the viewpoint of obtaining a cell structure having a high foaming ratio in the resin foam layer, the resin composition such as the thermoplastic resin composition may contain a shrinkage inhibitor. The shrinkage inhibitor is not particularly limited as long as it exhibits an effect of suppressing the permeation of the blowing agent gas, and, for example, fatty acid metal salts (e.g., aluminum, calcium, magnesium of fatty acids such as stearic acid, behenic acid, and 12-hydroxystearic acid), Salts of lithium, barium, zinc, lead, etc.); Fatty acid amide (fatty acid amide of about 12 to 38 carbon atoms (preferably about 12 to 22) of fatty acid (any of monoamide and bisamide may be used, but bisamide is suitably used to obtain a fine cell structure), for example , Stearic acid amide, oleic acid amide, erucic acid amide, methylene bisstearic acid amide, ethylene bisstearic acid amide, lauric acid bisamide, etc.] and the like. On the other hand, such shrinkage inhibitors can be used alone or in combination of two or more.

In resin compositions such as the thermoplastic resin composition, the amount (content) of the shrinkage inhibitor is not particularly limited. For example, when the thermoplastic resin composition is a resin composition containing the thermoplastic resin and ``a mixture containing a rubber and/or a thermoplastic elastomer, and a softener'', the amount of the shrinkage inhibitor added in the resin composition is not particularly limited. , With respect to 100 parts by mass of the total amount of the resin component, it is preferably 0.5 parts by mass to 10 parts by mass, more preferably 0.7 parts by mass to 8 parts by mass, and still more preferably 1 to 6 parts by mass. If the addition amount exceeds 10 parts by mass, the gas efficiency is lowered in the cell growth process, so that a small cell diameter is obtained, but the unfoamed portion also increases, and the expansion ratio may decrease. In addition, if it is less than 0.5 parts by mass, formation of the film is not sufficient, degassing occurs during foaming, shrinkage occurs, and the foaming ratio may decrease.

On the other hand, although it does not specifically limit as an additive, For example, you may use combining the said lubricant and the said shrinkage prevention agent. For example, a lubricant such as stearic acid monoglyceride and a shrinkage inhibitor such as erucic acid amide and lauric acid bisamide may be used in combination.

The manufacturing method of the said resin composition is not specifically limited. For example, the thermoplastic resin composition is not particularly limited, but may be produced by kneading the thermoplastic resin, other components as necessary, and additives added as necessary. Further, it may be obtained by kneading by a known melt-kneading extrusion device such as a single-screw (single-screw) kneading extruder or a twin-screw kneading extruder, and extruding.

Although it does not specifically limit as a form of the said resin composition, such as the said thermoplastic resin composition, For example, Strand shape; Sheet shape; Reputation; The strand is water-cooled or air-cooled, and a pellet shape is cut into an appropriate length. Among them, it is preferable to mix and pelletize from the viewpoint of productivity.

The resin foam layer in the resin foam composite of the present invention is not particularly limited, but is preferably formed by foaming the resin composition. In particular, after foaming the resin composition, the surface is further heated and melted. It is preferable to process to form a surface layer. For example, it is preferably formed by foaming the thermoplastic resin composition (eg, the polyolefin resin composition). In particular, after foaming the thermoplastic resin composition (eg, the polyolefin resin composition), it is preferable to further heat-melt the surface to form a surface layer.

Although it does not specifically limit as a method of foaming a resin composition, such as the said thermoplastic resin composition (for example, said polyolefin resin composition), For example, a physical foaming method and a chemical foaming method can be mentioned. The physical foaming method is a method of forming cells (bubbles) by impregnating (dispersing) a low boiling point liquid (foaming agent) into a resin composition and then volatilizing a foaming agent. In addition, the chemical foaming method is a method of forming cells with gas generated by thermal decomposition of a compound added to a resin composition. Among them, a physical foaming method is preferable, and a physical foaming method using a high-pressure gas as a foaming agent is more preferable from the viewpoint of avoiding contamination of the resin foam layer and easy to obtain a fine and uniform cell structure. Therefore, the resin foam layer in the resin foam composite of the present invention, in particular, to a resin composition such as the thermoplastic resin composition (for example, the polyolefin resin composition), a high pressure gas (for example, an inert gas described later) After impregnation, it is preferably formed by foaming.

The inert gas is not particularly limited, and examples thereof include carbon dioxide, nitrogen gas, air, helium, argon, and the like. Particularly, the inert gas is preferably carbon dioxide since the amount of impregnation into the resin composition such as the thermoplastic resin composition is large and the impregnation rate is high. Incidentally, the inert gas may be used alone or in combination of two or more.

The mixing amount (content, impregnation amount) of the foaming agent is not particularly limited, but is preferably 2% by mass to 10% by mass based on the total weight (100% by mass) of the resin composition such as the thermoplastic resin composition. By setting it within the said range, the apparent density of the said resin foam layer in the resin foam composite of this invention can be made into a predetermined range easily.

The inert gas is preferably in a supercritical state at the time of impregnation from the viewpoint of speeding up the impregnation rate into a resin composition such as a thermoplastic resin composition. For example, it is preferable that the resin foam layer in the resin foam composite of the present invention is formed by foaming the thermoplastic resin composition (eg, the polyolefin resin composition) using a supercritical fluid. When the inert gas is a supercritical fluid (supercritical state), the solubility in a resin composition such as a thermoplastic resin composition is increased, and impregnation (mixing) of a high concentration is possible. In addition, since it is possible to impregnate at a high concentration, when the pressure is rapidly lowered after impregnation, the generation of bubble nuclei increases, and the density of the bubbles formed by the growth of the bubble nuclei increases even if the porosity is the same, thus obtaining fine bubbles. I can. On the other hand, the critical temperature of carbon dioxide is 31°C and the critical pressure is 7.4 MPa.

As a physical foaming method using gas as a foaming agent, a resin composition such as a thermoplastic resin composition is impregnated with a high-pressure gas (e.g., inert gas, etc.), followed by a step of depressurizing (e.g., to atmospheric pressure) (a step of releasing pressure). A method of forming by foaming is preferred. Specifically, a non-foamed molded product is obtained by molding a resin composition such as a thermoplastic resin composition, and the non-foamed molded product is impregnated with a high-pressure gas, and then foamed through a step of reducing pressure (e.g., to atmospheric pressure). Or a method of impregnating a resin composition such as a molten thermoplastic resin composition with a gas (e.g., inert gas) under a pressurized state, then reducing the pressure (e.g., to atmospheric pressure) to foam, and submitting to molding to form, etc. Can be mentioned.

That is, in the case of forming the resin foam layer in the resin foam composite of the present invention, a resin composition such as the thermoplastic resin composition (eg, the polyolefin resin composition) is molded into a suitable shape such as a sheet, After making a foamed resin molded product (non-foamed molded product), this non-foamed resin molded product may be impregnated with a high-pressure gas and foamed by releasing the pressure, and may be carried out in a batch manner, or resin such as the thermoplastic resin composition. The composition may be kneaded together with a high-pressure gas under high-pressure conditions, molding, and releasing the pressure, and molding and foaming may be performed in a continuous manner.

In the above arrangement method, the method of forming the non-foamed resin molded body is not particularly limited, for example, a method of molding a resin composition such as a thermoplastic resin composition using an extruder such as a single screw extruder or a twin screw extruder; A method of uniformly kneading a resin composition such as a thermoplastic resin composition using a kneader equipped with blades such as rollers, cams, kneaders, Banbury type, etc., and press molding to a predetermined thickness using a press of a hot plate or the like; A method of molding a resin composition such as a thermoplastic resin composition using an injection molding machine, etc. are mentioned. In addition, the shape of the non-foamed resin molded body is not particularly limited, and examples thereof include a sheet shape, a roll shape, and a plate shape. In the above arrangement method, a non-foamed resin molded body is molded from a resin composition such as a thermoplastic resin composition by a suitable method for obtaining a non-foamed resin molded body having a desired shape or thickness.

In the above arrangement method, a gas impregnation process in which a non-foamed resin molded body is placed in a pressure-resistant container and a high-pressure gas is injected (introduced, mixed) to impregnate the gas into the non-foamed resin molded body, and the pressure is released when sufficiently impregnated with gas Then (usually to atmospheric pressure), a bubble structure is formed through a decompression step of generating bubble nuclei in the unfoamed resin molded body.

On the other hand, in the continuous method, (i) a resin composition such as a thermoplastic resin composition is kneaded using an extruder (e.g., a single screw extruder, a twin screw extruder, etc.) or an injection molding machine, while injecting (introducing, mixing) a high pressure gas. Then, the kneading impregnation step of impregnating a resin composition such as a thermoplastic resin composition with a sufficiently high pressure gas, (ii) extruding a resin composition such as a thermoplastic resin composition impregnated with gas through a die installed at the tip of the extruder A resin composition such as a thermoplastic resin composition is foam-molded by a molding decompression step in which the pressure is released (usually to atmospheric pressure) and molding and foaming are simultaneously performed.

In the above-described batch method or continuous method, if necessary, a heating step of growing bubble nuclei by heating may be provided. On the other hand, you may grow a bubble core at room temperature without providing a heating process. Further, after growing the air bubbles, if necessary, it may be rapidly cooled with cold water or the like to fix the shape. The high-pressure gas may be introduced continuously or discontinuously. On the other hand, the method of heating when growing the bubble core is not particularly limited, and known or commonly used methods such as a water bath, an oil bath, a heat roll, a hot air oven, a far infrared ray, a near infrared ray, and a microwave are mentioned.

In the batch method gas impregnation step or the continuous method kneading impregnation step, the pressure at the time of impregnating the gas is appropriately selected in consideration of the type and operability of the gas, but, for example, 5 MPa or more (e.g., 5 MPa to 100 MPa). ) Is preferable, more preferably 7 MPa or more (eg, 7 MPa to 100 MPa). That is, it is preferable to impregnate a resin composition such as the thermoplastic resin composition with a gas having a pressure of 5 MPa or more (e.g., pressure 5 MPa to 100 MPa), and impregnating an inert gas with a pressure of 7 MPa or more (e.g., pressure 7 MPa to 100 MPa). More preferable. When the pressure of the gas is lower than 5 MPa, bubble growth during foaming is remarkable, the cell becomes too large, and incompatibility such as, for example, a decrease in the dustproof effect, is liable to occur, which is not preferable. This is because when the pressure is low, the amount of impregnation of the gas is relatively small compared to the high pressure, and the bubble nucleus formation rate is lowered, so that the number of bubble nuclei formed decreases, so the amount of gas per bubble is increased oppositely, resulting in an extremely large bubble diameter. to be. Further, in a pressure region lower than 5 MPa, since the cell diameter and the cell density largely change only by slightly changing the impregnation pressure, control of the cell diameter and cell density is liable to be difficult.

In addition, in the gas impregnation step in the batch method or the kneading impregnation step in the continuous method, the temperature (impregnation temperature) at the time of impregnating the gas varies depending on the type of gas or resin to be used, and can be selected from a wide range. However, in the case of considering operability and the like, 10°C to 350°C is preferable. More specifically, the impregnation temperature in the batch method is preferably 10°C to 250°C, more preferably 40°C to 240°C, and still more preferably 60°C to 230°C. In addition, in the continuous system, the impregnation temperature is preferably 60°C to 350°C, more preferably 100°C to 320°C, and still more preferably 150°C to 300°C. On the other hand, in the case of using carbon dioxide as a high-pressure gas, in order to maintain a supercritical state, the temperature at the time of impregnation (impregnation temperature) is preferably 32°C or higher (especially 40°C or higher). Further, after impregnating with gas, before foaming, a resin composition such as a thermoplastic resin composition impregnated with gas may be cooled to a temperature suitable for foam molding (for example, 150°C to 190°C).

Further, in the batch method or the continuous method, the depressurization rate in the decompression step (the step of releasing the pressure) is not particularly limited, but from the viewpoint of obtaining a cell structure having uniform and fine cells, preferably 5 MPa/ It is from second to 300 MPa/second.

In order to grow the bubble nuclei, in the case of providing a heating step, the heating temperature is preferably 40°C to 250°C, and more preferably 60°C to 250°C, for example.

On the other hand, the cell structure and the apparent density of the resin foam layer in the resin foam composite of the present invention depend on the type of the constituent resin, for example, a foaming method or foaming method when foaming a resin composition such as a thermoplastic resin composition. It is adjusted by selecting the conditions (eg, the type and amount of the foaming agent, the temperature, pressure or time at the time of foaming).

In particular, the resin foam layer in the resin foam composite of the present invention is preferably formed by foaming a resin composition such as a thermoplastic resin composition and then slicing the surface. Specifically, after foaming a resin composition such as the thermoplastic resin composition to obtain a foam (sheet-shaped foam A), it is preferably formed by slicing the surfaces on both sides of the foam. The above sheet-shaped foam A (a foam obtained by foaming a resin composition such as the thermoplastic resin composition) is a layered portion having a high density compared to the inside (a layered portion having a low expansion ratio compared to the inside, a skin layer) near the surface. ) In many cases. According to the slicing process, this layered portion (skin layer) can be removed, the internal cell structure can be exposed on the surface of the foam, and an opening can be provided. Further, by slicing, a resin foam layer having an arbitrary thickness can be obtained with good thickness accuracy.

As the slicing process, the surface skin layer can be peeled off one by one using a continuous slicing apparatus (slice line) as shown in FIG. 1. That is, by passing a long foam original (eg, sheet-like foam A, etc.) through the continuous slicing device twice to remove the skin layer on the surface, openings are formed on both surfaces.

The resin foam layer used in the present invention preferably forms a surface layer by further heating and melting the surface after foaming the resin composition. In particular, after foaming the thermoplastic resin composition, it is preferable to further heat-melt the surface to form a surface layer. More specifically, after foaming a resin composition such as the thermoplastic resin composition to obtain a foam (sheet-shaped foam), it is preferable to form a surface layer by heat-melting the surface of the foam. Thus, by melting the surface in the thickness direction, the thickness of the resin foam layer can be thinly adjusted. Further, while suppressing the decrease in flexibility to a minimum, the tensile strength in the longitudinal direction is increased, the occurrence of breakage or tearing is suppressed, and a long resin foam layer can be easily and continuously obtained. In addition, by returning the foamed portion to the non-foaming state (bulk), the roughness (error in thickness) of the original surface becomes smaller, and the thickness accuracy is improved. Therefore, even at high speed, wrinkles (wound wrinkles at the time of winding) are reduced. It can suppress the outbreak. On the other hand, in this specification, as a sheet-like foam obtained by foaming the resin composition, the foam before heat-melt treatment is sometimes referred to as a "foam structure".

The heat-melting treatment is not particularly limited, but the foaming is to suppress the occurrence of wrinkles during winding, particularly wrinkles during winding at high speed, to obtain better winding stability, and to improve thickness accuracy. It is preferred that it be implemented entirely on at least one side of the structure. That is, in the case of forming the resin foam layer used in the present invention by foaming the thermoplastic resin composition and then further subjecting the surface to heat-melt treatment, after obtaining a foamed structure by foaming the thermoplastic resin composition, It is preferable to form by subjecting one side or both sides of the foamed structure to a heat-melt treatment. Moreover, you may heat-melt-process 2 or more times on the same surface.

Moreover, you may heat-melt-process using it as the resin foam composite which laminated|stacked the pressure-sensitive adhesive layer mentioned later. After forming a resin foam composite in which a foam structure and an adhesive layer are laminated, heat-melt treatment may be performed on the foam structure to form a surface layer.

Although it does not specifically limit as said heat-melt treatment, For example, a press treatment with a hot roll, a laser irradiation treatment, a contact melt treatment on a heated roll, a flame treatment, etc. are mentioned. In the case of a press treatment using a heat roll, it can be suitably treated using a heat laminator or the like. On the other hand, examples of the material of the roll include rubber, metal, and fluorine-based resin (for example, Teflon (registered trademark)).

The temperature at the time of the heat-melt treatment is not particularly limited, but is 15°C lower than the softening point or melting point of the resin contained in the foamed structure (more preferably 12°C lower than the softening point or melting point of the resin included in the foamed structure) It is preferable that it is above, and it is preferable that it is 20 degrees C higher than the softening point or melting point of the resin contained in the foamed structure (more preferably, 10 degreeC higher than the softening point or melting point of the resin contained in the foamed structure) or lower.

In addition, when heat-melting treatment is performed using a resin foam composite in which the pressure-sensitive adhesive layers are laminated, the temperature at the time of heat-melt treatment is not particularly limited, but it is preferably at least 40°C higher than the softening point or melting point of the resin.

For example, 15°C lower than the softening point or melting point of the thermoplastic resin (eg, the polyolefin resin, etc.) contained in the foamed structure (more preferably 12°C lower than the softening point or melting point of the thermoplastic resin included in the foamed structure) In addition, it is preferable that the temperature is 20°C higher than the softening point or melting point of the thermoplastic resin contained in the foamed structure (more preferably 10°C higher than the softening point or melting point of the thermoplastic resin included in the foamed structure). When the temperature at the time of the heat-melt treatment is higher than a temperature 15°C lower than the softening point or melting point of a resin such as a constituting thermoplastic resin, it is preferable from the viewpoint that the heat-melt treatment can be efficiently performed. In addition, when the temperature during the heat-melt treatment is lower than a temperature 20°C higher than the softening point or melting point of a resin such as a constituting thermoplastic resin, it is possible to suppress the occurrence of shrinkage and wrinkles, which is preferable.

In addition, the treatment time of the heat-melt treatment depends on the treatment temperature, but, for example, about 0.1 second to 10 seconds is preferable, and preferably about 0.5 second to 7 seconds. If the time is too short, melting may not proceed, and if the time is too long, it may shrink and wrinkles or the like may occur.

In particular, the heat-melting treatment suppresses the occurrence of wrinkles during winding, particularly during winding at high speed, to obtain better winding stability, and to further improve thickness precision, so that the foamed structure is It is preferable to use a heat-melting apparatus capable of adjusting the gap (gap, gap) passing through.

As such a heat-melt processing apparatus, a continuous processing apparatus including a heating roll (thermal dielectric roll) 23 capable of adjusting the gap in FIG. 2 is exemplified. That is, the foamed structure fed out from the feeding roll 21 is passed through the gap between the heating roll (thermal dielectric roll) 23 and the cooling roll 24, and is then passed through the heat roll (thermal dielectric roll) 23. Thus, a contact melting treatment is performed, and the resin foam layer having a surface layer formed thereon is wound by a take-up roll 25 by a heat melting treatment.

The resin foam constituting the resin foam layer in the resin foam composite of the present invention has a low apparent density, is thin and flexible, and is excellent in winding stability (winding stability). For this reason, a wide and long long roll can be obtained. Further, the resin foam constituting the resin foam layer is thin, and the thickness accuracy can be increased.

In the case where a surface layer is provided on the resin foam layer in the resin foam composite of the present invention, it is preferable that it is a surface having a surface coverage of 40% or more. That is, it is preferable that the resin foam layer has a surface layer having a surface coverage of 40% or more.

The surface coverage is preferably 40% or more, more preferably 45% or more, and still more preferably 50% or more.

The surface coverage is an index representing the ratio of non-porous portions (non-porous portions present on the surface, bulk, non-foamed portions) present on the surface, and is defined by the following equation (1). On the other hand, if the surface coverage is 100%, there is no hole in the surface.

Surface coverage (%) = [(surface area)-(area of holes existing on the surface)]/(surface area)×100 (1)

The thickness of the resin foam layer in the resin foam composite of the present invention is not particularly limited as long as it is designed so that the layer thickness of the resin foam composite is 0.35 mm or less, but it is preferably 0.03 mm to 0.34 mm, and 0.04 mm to 0.28. It is more preferable that it is mm, and it is more preferable that it is 0.05 mm-0.20 mm. If the thickness of the resin foam layer is within the above range, there is an advantage that it can be compressed and inserted into a narrow gap while maintaining high impact absorption. On the other hand, if the thickness of the resin foam is less than 0.03 mm, the main purpose of impact absorption may be lowered. On the other hand, if the thickness of the resin foam exceeds 0.34 mm, it may not be inserted into a narrow gap such as 0.1 mm. On the other hand, in the resin foam composite of the present invention, the thickness of the resin foam layer refers to the thickness including the surface layer.

Although the value calculated by the following formula (2) of the resin foam layer in the resin foam composite of the present invention is not particularly limited, it is preferably 25% or less, more preferably 15% or less, further preferably 10%. Below. When the "value obtained from the equation (2)" is within 25%, occurrence of wrinkles during winding, particularly wrinkles during winding at high speed, can be suppressed and better winding stability can be obtained, which is preferable. Further, since high thickness precision can be obtained, it is preferable to prevent occurrence of wrinkles at the time of bonding with the pressure-sensitive adhesive layer. In addition, in this specification, the high speed at the time of winding means, for example, a speed of 10 to 40 m/min.

(Thickness tolerance)/(Center value of thickness)×100 (2)

Thickness tolerance: The thickness is measured every 10 mm in the width direction from one point in the length direction to the other end, and from one point in the length direction in the length direction, the thickness is measured from one end to the other. It refers to the difference between the maximum and minimum values of all measured values obtained by measuring the thickness every 10 mm in the width direction to the end.

Center value of thickness: The thickness is measured every 10 mm in the width direction from one point in the length direction to the other end, and from one point in the length direction to the other at a point moved 1 m in the length direction. The thickness is measured every 10 mm in the width direction to the end of the side, and when all the obtained measured values are arranged in small order, it refers to the value located in the center.

In the resin foam layer in the resin foam composite of the present invention, the resin foam used for the resin foam layer may be a sheet-like material or may be wound up and in a roll shape (wound body).

In the resin foam layer in the resin foam composite of the present invention, when the resin foam used for the resin foam layer is produced as a sheet-like material, the width is not particularly limited, but it is preferably 300 mm or more (for example, 300 mm to 1500 mm). And, it is more preferably 400 mm or more (for example, 400 mm to 1200 mm), and more preferably 500 mm or more (for example, 500 mm to 1000 mm). Since the width is 300 mm or more, it is preferable to design or process a high degree of freedom.

In addition, in the resin foam layer in the resin foam composite of the present invention, when the resin foam used for the resin foam layer is produced as a sheet-like material, the length is not particularly limited, but not less than 5 m (for example, 5 m to 1000 m). It is preferable that it is 30m or more (for example, 30m-500m), and it is more preferable that it is 50m or more (for example, 50m-300m).

[Adhesive layer]

In the resin foam composite of the present invention, the pressure-sensitive adhesive layer refers to a layered product that provides an adhesive surface to the resin foam layer and an adhesive surface to an adherend. For example, in the pressure-sensitive adhesive layer in the resin foam composite of the present invention, a double-sided pressure-sensitive adhesive sheet without a substrate (a pressure-sensitive adhesive sheet composed of only one pressure-sensitive adhesive layer) or a double-sided pressure-sensitive adhesive sheet with a substrate (a pressure-sensitive adhesive sheet having pressure-sensitive adhesive layers on both sides of the substrate) ), a pressure-sensitive adhesive layer with a substrate to be described later, and the like.

The pressure-sensitive adhesive layer in the resin foam composite of the present invention is not particularly limited, but examples include acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives (natural rubber-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, etc.), silicone-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, poly It can be formed with an adhesive such as an amide adhesive, an epoxy adhesive, a vinyl alkyl ether adhesive, or a fluorine adhesive. In particular, since it has high adhesive properties and heat resistance, it is preferable to use an acrylic adhesive. The pressure-sensitive adhesive may be used alone or in combination of two or more. On the other hand, 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-type pressure-sensitive adhesive, an oligomer-based pressure-sensitive adhesive, and a high-based pressure-sensitive adhesive.

Particularly, since the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer in the resin foam composite of the present invention has high transparency and excellent heat resistance and light resistance, an acrylic pressure-sensitive adhesive is preferable. That is, it is preferable that the adhesive layer in the resin foam composite of this invention is an acrylic adhesive layer.

The pressure-sensitive adhesive contains a base polymer and, if necessary, suitable additives such as a crosslinking agent, a tackifier, a softener, a plasticizer, a filler, an anti-aging agent, and a colorant. For example, the acrylic pressure-sensitive adhesive includes an acrylic polymer as an adhesive component (base polymer) or main material, and if necessary, suitable additives such as a crosslinking agent, a tackifier, a softener, a plasticizer, a filler, an anti-aging agent, and a colorant are included. have.

In the acrylic pressure-sensitive adhesive, in the acrylic polymer, an alkyl (meth)acrylate is used as a monomer main component, and if necessary, a monomer capable of copolymerization with the alkyl (meth)acrylate (copolymerizable monomer) is another monomer component. It is preferably used as. Examples of the alkyl (meth)acrylate ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, ( S-butyl meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylate )Isooctyl acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, (meth) Tridecyl acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, (meth) acrylic acid (Meth)acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms such as eicosyl (sometimes referred to as "(meth)acrylic acid C _1-20 alkyl ester") is mentioned. Examples of the (meth)acrylic acid alkyl ester include, among others, a (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms (a case referred to as ``(meth)acrylic acid C _4-18 alkyl ester'') Yes) is mentioned preferably. The said (meth)acrylic acid alkyl ester can be appropriately selected depending on the target adhesiveness and the like. In addition, the said (meth)acrylate alkyl ester may be used individually or in combination of 2 or more types.

Further, examples of the copolymerizable monomer in the acrylic polymer include carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, or anhydrides thereof; Sulfonic acid group-containing monomers such as sodium vinyl sulfonate; Aromatic vinyl compounds such as styrene and substituted styrene; Cyano group-containing monomers such as acrylonitrile; Olefins such as ethylene, propylene, and butadiene; Vinyl esters such as vinyl acetate; Vinyl chloride; Amide group-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, and N,N-dimethyl(meth)acrylamide; Hydroxyl group-containing monomers such as hydroxyalkyl (meth)acrylate and glycerindimethacrylate; Amino group-containing monomers such as aminoethyl (meth)acrylate and (meth)acryloylmorpholine; Imide group-containing monomers such as cyclohexyl maleimide and isopropyl maleimide; Epoxy group-containing monomers such as glycidyl (meth)acrylate and methylglycidyl (meth)acrylate; And isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate. In addition, triethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylic Rate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, And polyfunctional copolymerizable monomers (polyfunctional monomers) such as divinylbenzene. These copolymerizable monomers may be used alone or in combination of two or more. As a copolymerizable monomer, a monomer for modification which has functional groups, such as a carboxyl group, is mentioned suitably.

The base polymer in the pressure-sensitive adhesive can be prepared by a commonly used polymerization method. For example, the acrylic polymer can be prepared by a conventional polymerization method such as a solution polymerization method, an emulsion polymerization method, and an ultraviolet irradiation polymerization method.

The pressure-sensitive adhesive layer can be formed using a known or common forming method, for example, a method of applying a pressure-sensitive adhesive on a predetermined area or surface (coating method), and applying the pressure-sensitive adhesive on a release film such as a release liner for adhesion. After forming the layer, a method of transferring the pressure-sensitive adhesive layer onto a predetermined portion or surface (transfer method), etc. are mentioned. On the other hand, in the formation of the pressure-sensitive adhesive layer, a known or common application method (flexible method, roll coater method, reverse coater method, doctor blade method, etc.) can be appropriately used.

The pressure-sensitive adhesive layer in the resin foam composite of the present invention may be a single layer or a laminate. Further, the pressure-sensitive adhesive layer in the resin foam composite of the present invention may be a pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer with a substrate containing a suitable substrate. The adhesive layer with a substrate may be, for example, a double-sided adhesive type having an adhesive layer on both sides of the substrate. On the other hand, when the pressure-sensitive adhesive layer in the resin foam composite of the present invention is the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer with a substrate, the total thickness of the resin foam composite includes the thickness of the resin foam and the thickness of the pressure-sensitive adhesive layer with a substrate.

That is, the resin foam composite of the present invention may be a resin foam composite in which the resin foam layer and the pressure-sensitive adhesive layer with a substrate are laminated. For example, in the resin foam composite of the present invention, the resin foam layer, the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer with a substrate, the substrate in the pressure-sensitive adhesive layer with the substrate, and the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer with a substrate, in this order You may have a structure laminated with On the other hand, this configuration corresponds to a configuration in which the above resin foam layer and a double-sided adhesive type adhesive layer with a base material are laminated.

The pressure-sensitive adhesive layer with a substrate may be a pressure-sensitive adhesive layer with a substrate in which a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive is provided on both surfaces of a paper-based substrate, a fiber-based substrate, a metal-based substrate, a plastic-based substrate such as a PET film. On the other hand, when the adhesive layer with a base material is a double-sided adhesive type, the composition of the two adhesive layers may be the same or different. In addition, the thickness of the two pressure-sensitive adhesive layers may be the same or different.

Although it does not specifically limit as a material of a base material in the said adhesive layer with base material, Plastic material is suitable. As such a plastic material (material of a plastic film), various engineering plastic materials are mentioned suitably. Examples of the plastic material include polyester (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.); Olefin-based resins [olefin-based resins containing α-olefins as a monomer component such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer (EVA)]; Polyethersulfone (PES) (polyethersulfone); Polysulfone; Polyvinyl chloride (PVC); Polyphenylene sulfide (PPS); Amide resin [polyamide (nylon), wholly aromatic polyamide (alamide), etc.], polyimide (PI), polyamideimide, polyetherimide (PEI), polyesterimide, methacrylate resin [poly Methyl methacrylate (PMMA), etc.]; Styrene resins (polystyrene, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), etc.); Polycarbonate (PC); Polyacetal; Polyarylene ether (polyphenylene ether, etc.); Polyphenylene sulfide; Polyallylate; Polyaryl; Polyurethanes; Polyether ketones [polyether ether ketone (PEEK), polyether ketone ketone, etc.]; Polyacrylic acid esters [butyl polyacrylate, ethyl polyacrylate, etc.]; Epoxy resin, etc. are mentioned. These materials (plastic materials) may be used alone or in combination of two or more.

As the plastic material, from the viewpoints of thickness accuracy, economy (cost), tensile strength, workability, and the like, polyester (especially polyethylene terephthalate) is suitably mentioned. That is, as the substrate in the pressure-sensitive adhesive layer with a substrate, a polyester film (especially, a polyethylene terephthalate film) is particularly preferably mentioned.

On the other hand, the substrate may have either a single layer or a laminated layer, and is not subject to structural restrictions.

The thickness of the substrate is not particularly limited, but is preferably 0.0005 mm to 0.038 mm, more preferably 0.001 mm to 0.025 mm, and still more preferably 0.002 mm to 0.012 mm.

In addition, the adhesive surface may be protected by a release film (separator) (for example, a release paper, a release film, etc.) in the said adhesive layer. On the other hand, the release film (separator) is not included in the total thickness of the resin foam composite of the present invention.

The thickness of the pressure-sensitive adhesive layer in the resin foam composite of the present invention is 0.0005 mm to 0.06 mm, preferably 0.0007 mm to 0.05 mm, more preferably 0.001 mm to 0.04 mm, further preferably 0.002 mm. It is ∼0.04mm. When the thickness of the pressure-sensitive adhesive layer is within the above range, there is an advantage that the foam can be compressed while maintaining an appropriate adhesive force. On the other hand, if the thickness of the pressure-sensitive adhesive layer is less than 0.0005 mm, sufficient adhesive strength cannot be obtained, on the other hand, if the thickness of the pressure-sensitive adhesive layer exceeds 0.06 mm, even if the pressure-sensitive adhesive layer is compressed in the thickness direction, the thickness of the pressure-sensitive adhesive layer after compression is sufficiently small. In some cases, the foam may not be smaller than the size of the gap to be applied even when the foam is compressed. As a result, when applying the resin foam composite to the gap, it may become difficult to use. On the other hand, in the resin foam composite of the present invention, the thickness of the pressure-sensitive adhesive layer refers to the thickness including the substrate when the pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer with a substrate. For example, when the pressure-sensitive adhesive layer in the resin foam composite of the present invention is a pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer with a substrate of a double-sided adhesive type, the thickness of the pressure-sensitive adhesive layer includes the thickness of the substrate and two on both sides of the substrate. The thickness of the adhesive layer is included.

[Resin foam composite]

The resin foam composite of the present invention has a structure in which the resin foam layer and the pressure-sensitive adhesive layer are laminated. If it has a pressure-sensitive adhesive layer, it is advantageous for fixation to an adherend or temporary fixation, and is advantageous in terms of assembly properties. On the other hand, the shape of the resin foam composite of the present invention is not particularly limited, but may be a sheet (film) or roll, and may be punched or cut into various shapes depending on the application.

The method for producing the resin foam composite of the present invention is not particularly limited. For example, the resin foam composite of the present invention is produced by providing the pressure-sensitive adhesive layer on the resin foam layer. When installing the pressure-sensitive adhesive layer on the resin foam layer, by adjusting the tension applied to the resin foam layer and the pressure-sensitive adhesive layer to be as low as possible, even if the thickness of the resin foam layer and the pressure-sensitive adhesive layer is very thin, wrinkles, etc. are not generated. , It is possible to manufacture a resin foam composite in a good state, particularly a good appearance state. The tension at the time of applying tension for the purpose of producing a resin foam composite in a good state, particularly in a good appearance state, is not particularly limited, but for example, when the width of the resin foam layer and the pressure-sensitive adhesive layer is 500 mm, 1 to 100 N is preferable. And more preferably 1 to 90 N, and still more preferably 2 to 80 N. In addition, when the width of the resin foam layer and the pressure-sensitive adhesive layer is 1000 mm, the tension is preferably 2 to 200 N, more preferably 2 to 180 N, and still more preferably 4 to 160 N. For example, when a tension of 100 N or more with a width of 500 mm and a tension of 200 N or more with a width of 1000 mm is applied, and the thickness of the resin foam layer and the pressure-sensitive adhesive layer is thin, the resin foam layer and the pressure-sensitive adhesive layer become elongated by the tension, and in the subsequent process , When the tension on the resin foam layer and the pressure-sensitive adhesive layer is removed, the resin foam layer and the pressure-sensitive adhesive layer shrink from the elongated state to the original state (shrink), and wrinkles when installing the pressure-sensitive adhesive layer on the resin foam layer by bonding, etc. It becomes easy to have back. On the other hand, the tension related to the resin foam layer and the pressure-sensitive adhesive layer is adjusted as, for example, a winding tension when winding in a roll shape when obtaining a long resin foam composite.

In the resin foam composite of the present invention, the pressure-sensitive adhesive layer may be provided only on one side of the resin foam layer, or may be provided on both sides. In addition, when the resin foam layer has a surface layer formed by heat-melting treatment, the pressure-sensitive adhesive layer may be provided on the surface having the surface layer in the resin foam layer, and does not have a surface layer in the resin foam layer. Although it may be provided on a surface, it is preferable to provide it on a surface not having a surface layer of the resin foam layer. On the other hand, in the resin foam composite of the present invention, the resin foam layer and the pressure-sensitive adhesive layer may be configured to be in direct contact with each other, but an intermediate layer such as a undercoat layer may be provided for the purpose of improving adhesion.

The total thickness of the resin foam composite of the present invention is 0.35 mm or less. The total thickness of the resin foam composite is not particularly limited as long as it is 0.35 mm or less, but is preferably 0.06 mm to 0.33 mm, more preferably 0.07 mm to 0.30 mm, and still more preferably 0.08 mm to 0.25 mm. Since the total thickness is 0.35 mm or less, even if the gap to which the resin foam composite is applied is small, the functions of the resin foam (eg, sealability, flexibility, shock absorption, etc.) can be exhibited. Further, when the total thickness of the resin foam composite is 0.05 mm or more, it becomes easy to secure the required strength.

In the resin foam composite of the present invention, the ratio of the thickness of the resin foam layer and the thickness of the pressure-sensitive adhesive layer (the thickness of the resin foam layer/the thickness of the adhesive layer) is not particularly limited, but the resin foam layer is 2.1 or more. And it is preferable to determine the thickness of the pressure-sensitive adhesive layer. The ratio of the thickness of the resin foam layer and the thickness of the pressure-sensitive adhesive layer (thickness of the resin foam layer/thickness of the adhesive layer) is more preferably 3.0 or more, and still more preferably 5.0 or more. In addition, the ratio of the thickness of the resin foam layer and the thickness of the pressure-sensitive adhesive layer (thickness of the resin foam layer/thickness of the adhesive layer) is usually 13 or less, and preferably 11 or less. If the ratio of the thickness is 2.1 or more, there is an advantage that the foam can also be compressed within an appropriate range of adhesive strength. That is, since the foam can be compressed while securing sufficient adhesive force, the resin foam composite can be suitably applied to a smaller gap.

The resin foam composite of the present invention is suitably used for a purpose of attaching (attaching) various members or parts to predetermined sites. In particular, in an electric or electronic device, it is suitably used when attaching (mounting) components constituting the electric or electronic device to a predetermined portion. That is, it is preferable that the resin foam composite of this invention is for electric or electronic devices.

Although it does not specifically limit as said various members or parts, For example, various members or parts etc. in electric or electronic devices are mentioned preferably. As such a member or component for an electric or electronic device, for example, an image display member (display unit) (especially a small image display member) mounted on an image display device such as a liquid crystal display, an electroluminescent display, or a plasma display, or a so-called Optical members or optical parts, such as a camera or a lens (especially, a small camera or lens) mounted on a mobile communication device such as a "mobile phone" or a "mobile information terminal", may be mentioned.

More specifically, the resin foam composite of the present invention is for the purpose of vibration-proofing, light-shielding, buffering, etc., around a display portion such as an LCD (liquid crystal display), or a display portion and a housing (window portion) such as an LCD (liquid crystal display). It can be used between )).

In addition, the resin foam composite of the present invention is thin and flexible, and the thickness accuracy can be increased. For this reason, even if the resin foam composite of the present invention is used in an electric or electronic device in which a number of parts or members are laminated, such as a smart phone equipped with a touch panel, it does not cause a high repulsive force. It does not cause display defects such as unevenness.

Example

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

[Example]

Polypropylene [melting flow rate (MFR): 0.35 g/10 min]: 45 parts by mass, a mixture of polyolefin elastomer and softener (paraffinic extender oil) [MFR (230°C): 6 g/10 min, JIS A Hardness: 79°, 30 parts by mass of softener blended with respect to 100 parts by mass of polyolefin elastomer]: 55 parts by mass, magnesium hydroxide: 10 parts by mass, carbon (brand name "Asahi #35" manufactured by Asahi Carbon Co., Ltd.): 10 parts by mass, Stearic acid monoglyceride: 1 part by mass, and fatty acid amide (lauric acid bisamide): 1.5 parts by mass, kneaded at a temperature of 200°C with a twin-screw kneader manufactured by Japan Steel Works (JSW), and then extruded into strands. Then, it was molded into pellets after water cooling. This pellet was put into a single screw extruder manufactured by Nippon Steelworks Co., Ltd., and carbon dioxide gas was injected under an atmosphere of 220°C at a pressure of 13 (12 MPa after injection). Carbon dioxide gas was injected at a ratio of 5.7 mass% based on the total amount of the pellets. After sufficient saturation of carbon dioxide gas, cooling to a temperature suitable for foaming, the mandrel is extruded from the die in a cylindrical shape to cool the inner surface of the foam, and the outer surface of the cylindrical foam extruded from the annular die of the extruder is cooled. It passed through the said foam cooling air ring, cut a part of the diameter, and expanded into a sheet shape, and obtained the long foam disk.

This elongated foam original is cut to a predetermined width (slit processing), and the low foaming layer on the surface is peeled off one by one using a continuous slicing device (slice line) shown in Fig. 1, and resin foam layer A and resin having different thicknesses A foam layer B and a resin foam layer C were obtained. In addition, in the resin foam layer A, the resin foam layer B, and the resin foam layer C, the average cell diameter was 60 µm and the apparent density was 0.047 g/cm ³ .

Resin foam layer A: 0.20 mm thick

Resin foam layer B: 0.30 mm thick

Resin foam layer C: 0.40 mm thick

(Example 1)

To one side of the resin foam layer A, a double-sided adhesive tape (trade name "No. 5603", manufactured by Nitto Denko, an adhesive tape having an acrylic adhesive layer on both sides of a PET substrate, tape thickness: 0.03 mm) was bonded to form resin foam. A composite was obtained. The total thickness of this resin foam composite was 0.23 mm.

(Example 2)

To one side of the resin foam layer B, a double-sided adhesive tape (trade name "No. 5603", manufactured by Nitto Denko, an adhesive tape having an acrylic adhesive layer on both sides of a PET substrate, tape thickness: 0.03 mm) was bonded to form resin foam. A composite was obtained. The total thickness of this resin foam composite was 0.33 mm.

(Example 3)

The resin foam layer A is passed through the continuous processing apparatus in which the temperature of the induction heating roll is set to 160° C. and the gap is set to 0.10 mm, thereby melting one side with heat, and having a thickness of 0.10 mm in which one side is heat-melted. The resin foam layer was obtained. The surface coverage of the hot-melt-treated surface layer was 89.1%. Thereafter, a double-sided adhesive tape (trade name ``No. 5603'', manufactured by Nitto Denko, an adhesive tape having an acrylic adhesive layer on both sides of a PET substrate, tape thickness: 0.03 mm) was bonded to the surface not subjected to heat melting treatment. , A resin foam composite was obtained. The total thickness of this resin foam composite was 0.13 mm.

(Example 4)

To one side of the resin foam layer A, a double-sided adhesive tape (trade name "No. 5603", manufactured by Nitto Denko, an adhesive tape in which an acrylic adhesive layer was provided on both sides of a PET substrate, tape thickness: 0.03 mm) was bonded. The total thickness of the obtained structure was 0.23 mm. With a PET release liner (thickness 0.075 mm) that protects the pressure-sensitive adhesive layer surface affixed, the structure is passed through the continuous processing apparatus in which the temperature of the induction heating roll is set to 220°C and the gap is set to 0.15 mm. The surface of the structure on which the double-sided adhesive tape was not affixed was melt-treated with heat to obtain a resin foam composite. In this resin foam composite, the thickness of the resin foam layer on which one side was heat-melted was 0.07 mm, the thickness of the pressure-sensitive adhesive layer was 0.03 mm, and the total thickness was 0.10 mm. In addition, the surface coverage of the hot melt-treated surface layer was 88.4%.

(Example 5)

The resin foam layer A is passed through the continuous processing apparatus in which the temperature of the induction heating roll is set to 160° C. and the gap is set to 0.10 mm, thereby melting one side with heat, and having a thickness of 0.10 mm in which one side is heat-melted. The resin foam layer was obtained. The surface coverage of the heat-melt-treated surface layer in this resin foam layer was 89.1%. Thereafter, a double-sided adhesive tape (trade name ``No. 5601'', manufactured by Nitto Denko, an adhesive tape in which an acrylic adhesive layer was provided on both sides of a PET substrate, tape thickness: 0.01) on the surface of the resin foam layer not subjected to heat melting treatment. mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.11 mm.

(Example 6)

To one side of the resin foam layer A, a double-sided adhesive tape (trade name "No. 5601", manufactured by Nitto Denko, an adhesive tape having an acrylic adhesive layer provided on both sides of a PET substrate, tape thickness: 0.01 mm) was bonded. The total thickness of the obtained structure was 0.21 mm. With a PET release liner (thickness 0.075mm) that protects the pressure-sensitive adhesive layer surface affixed, the structure is passed through the continuous processing apparatus in which the temperature of the induction heating roll is set to 220°C and the gap is set to 0.15mm, The surface to which the adhesive tape was not affixed was melt-treated with heat to obtain a resin foam composite. In this resin foam composite, the thickness of the resin foam layer on which one side was heat-melted was 0.07 mm, the thickness of the pressure-sensitive adhesive layer was 0.01 mm, and the total thickness was 0.08 mm. In addition, the surface coverage of the hot melt-treated surface layer was 94.1%.

(Example 7)

The resin foam layer A is passed through the continuous processing apparatus in which the temperature of the induction heating roll is set to 160° C. and the gap is set to 0.10 mm, thereby melting one side with heat, and having a thickness of 0.10 mm in which one side is heat-melted. The resin foam layer was obtained. The surface coverage of the heat-melt-treated surface layer in this resin foam layer was 89.1%. Thereafter, on the surface of the resin foam layer that has not been subjected to heat melting treatment, a double-sided adhesive tape (trade name "No. 5600", manufactured by Nitto Denko, an adhesive tape in which an acrylic adhesive layer is provided on both sides of a PET substrate, and the thickness of the tape : 0.005 mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.105 mm.

(Comparative Example 1)

To one side of the resin foam layer A, a double-sided adhesive tape (trade name "No. 5610", manufactured by Nitto Denko, an adhesive tape having an acrylic adhesive layer on both sides of a PET substrate, tape thickness: 0.10 mm) was bonded to form resin foam. A composite was obtained. The total thickness of this resin foam composite was 0.30 mm.

(Comparative Example 2)

To one side of the resin foam layer C, a double-sided adhesive tape (trade name "No. 5603", manufactured by Nitto Denko, an adhesive tape having an acrylic adhesive layer on both sides of a PET substrate, tape thickness: 0.03 mm) was bonded to form resin foam. A composite was obtained. The total thickness of this resin foam composite was 0.43 mm.

(Comparative Example 3)

The resin foam layer A is passed through the continuous processing apparatus in which the temperature of the induction heating roll is set to 160° C. and the gap is set to 0.10 mm, thereby melting one side with heat, and having a thickness of 0.10 mm in which one side is heat-melted. The resin foam layer was obtained. The surface coverage of the heat-melt-treated surface layer in this resin foam layer was 87.2%. Thereafter, a double-sided adhesive tape (trade name ``No. 5608'', manufactured by Nitto Denko, an adhesive tape in which an acrylic adhesive layer is provided on both sides of a PET substrate, tape thickness on the surface of the resin foam layer not subjected to heat melting treatment) : 0.08 mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.18 mm.

(Comparative Example 4)

On the PET side of urethane foam (brand name ``PORON SR-S-32P'', thickness 0.20mm, foam layer density 0.32g/cm ³ , made by Roger Suinoax), one side is supported by PET film, double-sided adhesive tape ( A brand name "No. 5603", manufactured by Nitto Denko Corporation, an adhesive tape having an acrylic adhesive layer provided on both surfaces of a PET substrate, and a tape thickness: 0.03 mm) were bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.23 mm.

(Comparative Example 5)

Polyolefin-based foam (trade name "Bolara WF03", manufactured by Sekisui Chemical Industries, Ltd., thickness 0.30mm, density: 0.20g/cm ³ , in sheet form), double-sided adhesive tape (brand name "No. 5603", manufactured by Nitto Denko, PET A pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of the substrate, tape thickness: 0.03 mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.33 mm.

[evaluation]

(Apparent density)

The resin foam layer was punched out in a punching blade shape having a width of 40 mm x a length of 40 mm to obtain a sheet-shaped sample for measurement. And from the sample for measurement, the apparent density (g/cm ³ ) was calculated according to JIS K 6767.

Specifically, the width and length of the measurement sample were measured, and the thickness (mm) of the measurement sample was measured with a 1/100 dial gauge having a diameter (φ) of 20 mm of the measurement terminal. The volume (cm ³ ) of the resin foam layer was calculated from these measured values. Next, the mass (g) of the sample for measurement was measured with a top plate balance of 0.01 g or more of the minimum scale. The apparent density (g/cm ³ ) was calculated from the measured values of the volume and mass.

(Average cell diameter)

By taking an enlarged image of the foam part with a digital microscope (brand name "VHX-500" manufactured by Giens Corporation) and analyzing the image using image analysis software (brand name "Win ROOF" manufactured by Mitani Corporation), The average cell diameter (μm) was calculated. On the other hand, the number of bubbles in the blown enlarged image is about 100.

(Surface coverage)

The surface coverage of the melt-treated surface of the resin foam layer was measured, and the value was taken as the surface coverage of the resin foam layer.

The surface coverage was calculated|required from following formula (1).

Surface coverage (%) = [(surface area)-(area of holes existing on the surface)]/(surface area)×100 (1)

The area of the surface and the area of the pores present on the surface were determined from the image of the measurement surface obtained using a microscope (device name "VHX600", manufactured by Giens Corporation).

In observation with a microscope, side-view illumination was employed as an illumination method, and the illuminance was 17,000 lux. In addition, the magnification was 500 times.

A built-in illumination lens camera (device name "0P72404", manufactured by Giens Co., Ltd.) was used as both the lighting and camera, and a zoom lens (brand name “VH-Z100”, manufactured by Giens Corp.) was used as the lens.

On the other hand, the illuminance was adjusted using an illuminance meter (brand name "VHX600", manufactured by Custom Corporation).

(Compression load at 50% compression)

Based on JIS K 6767, after compression by 50% of the initial foam thickness in the thickness direction of the resin foam layer, the stress (N) after 10 seconds is measured, and the corresponding stress is measured per unit area (cm ² ). In conversion, it was set as the compressive stress (N/cm ² ) at 50% compression. The results are shown in Tables 1 and 2.

(Compression load when 0.10mm is inserted)

For the resin foam composites of Examples and Comparative Examples, based on JIS K 6767, the stress (N) when 10 seconds elapsed after compression so as to have a thickness of 0.10 mm in the thickness direction was measured, and the stress was measured in a unit area ( It converted into per cm ² ), and it was set as the compressive load (N/cm ² ) at the time of 0.10 mm insertion. If the compressive load at the time of insertion of 0.10 mm is 3.5 N/cm ² or less, it is judged that it has flexibility that does not cause deformation or the like even when used for a narrow gap of 0.1 mm. The results are shown in Tables 1 and 2.

(Compressive load at the time of 0.05mm insertion)

For the resin foam composites of Examples and Comparative Examples, based on JIS K 6767, the stress (N) when 10 seconds elapsed after compression so as to have a thickness of 0.05 mm in the thickness direction was measured, and the stress was measured in a unit area ( It converted into per cm ² ), and it was set as the compressive load (N/cm ² ) at the time of insertion of 0.05 mm. If the compressive load at the time of insertion of 0.05 mm is 3.5 N/cm ² or less, it is judged that it has flexibility that does not cause deformation or the like even if it is used for a narrow gap of 0.05 mm. The results are shown in Tables 1 and 2.

(adhesiveness)

After storing the resin foam composite (width: 20 mm x length: 120 mm) in an atmosphere of temperature: 23±2°C and humidity: 50±5%RH for 24 hours or more (pretreatment conditions are in accordance with JIS Z 0237), adherend In a form in which (SUS) and the surface of the pressure-sensitive adhesive layer of the resin foam composite were in contact, pressure-bonded under the conditions of a 2 kg roller and one reciprocation, and allowed to stand for 30 minutes to obtain a sample for measurement. Then, with a universal tensile tester (equipment name "TCN-1kNB" manufactured by Minevea), in an atmosphere of temperature: 23±2°C, humidity: 50±5%RH, one end of the resin foam composite was pulled at a tensile speed of 300 mm/ The adhesive force when peeled at min, peeling angle 90 degrees was measured. If the adhesive force is 2N/20mm or more, it is judged that it has an adhesive force that does not interfere with alignment at the time of bonding operation. The results are shown in Tables 1 and 2.

In the examples, by using a resin foam layer having an apparent density of 0.03 to 0.30 g/cm ³ and a compressive stress at 50% compression of 5.0 N/cm ² or less, combined with a pressure-sensitive adhesive layer having a thickness of 0.005 mm to 0.06 mm, By setting it as a resin foam composite having a total thickness of 0.35 mm or less, a good result was obtained that the compressive load was 3.5 N/cm ² or less in a considerable evaluation when inserted into a gap of 0.1 mm. In addition, it was possible to obtain a resin foam composite that was adaptable to a gap of 0.05 mm. In addition, it is judged that the adhesive force at that time also has an adhesive force that does not interfere with alignment during the bonding operation.

On the other hand, in Comparative Examples 1 and 3, the thickness of the pressure-sensitive adhesive layer is more than a specific range, and in Comparative Example 2, since the total thickness of the resin foam composite is more than a specific range, the compressive load value at the time of 0.1 mm insertion You can see that it gets higher. In addition, it can be seen that in Comparative Example 4, which is a foam having an apparent density of not less than a specific value, the cushioning property is insufficient, and the compressive load value at the time of 0.1 mm insertion is increased. In addition, in Comparative Example 5 using a foam in which the compressive stress at 50% compression was equal to or higher than a specific value, it was found that the cushioning property was insufficient, and the compressive load value at the time of 0.1 mm insertion was increased.

The resin foam composite of the present invention is used, for example, in applications such as a vibration isolator, a sealing material, a sound insulation material, a buffer material, etc. used when attaching various members or parts to a predetermined site.

1: Continuous slicing device (slice line)
11: feed roll
12: pinch roll
13: Blade (slice blade)
14: guide roll
15: winding roll
16: resin foam
2: Continuous processing device with heating roll
21: feed roll
22: guide roll
23: heating roll (thermal dielectric roll)
24: cooling roll
25: winding roll
26: resin foam
a: flow direction

Claims (11)

A resin foam composite in which a resin foam layer and an adhesive layer are laminated,
The resin foam layer has an apparent density of 0.03 to 0.30 g/cm ^3, and a compressive stress at 50% compression is 5.0 N/cm ² or less,
The thickness of the pressure-sensitive adhesive layer is 0.0005 mm to 0.06 mm,
The total thickness of the resin foam composite is 0.35mm or less,
A resin foam composite having a compressive load (according to JIS K 6767) of 3.5 N/m ² or less at the time of insertion of 0.10 mm. The method of claim 1,
The resin foam composite, wherein the ratio of the thickness of the resin foam layer and the thickness of the pressure-sensitive adhesive layer (thickness of the resin foam layer/thickness of the adhesive layer) is 2.1 or more. The method according to claim 1 or 2,
The pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer, a resin foam composite. The method according to claim 1 or 2,
The resin foam composite, wherein the resin constituting the resin foam layer is a thermoplastic resin. The method of claim 4,
The thermoplastic resin is a polyolefin resin, resin foam composite. The method according to claim 1 or 2,
A resin foam composite having a surface layer formed by heat melting treatment on at least one surface of the resin foam layer. The method according to claim 1 or 2,
The resin foam composite, wherein the resin foam layer is formed through a step of reducing pressure after impregnating a resin with a high-pressure gas. The method of claim 7,
The resin foam composite, wherein the gas is an inert gas. The method of claim 8,
The inert gas is carbon dioxide, the resin foam composite. The method of claim 7,
The high-pressure gas is in a supercritical state, the resin foam composite. The method according to claim 1 or 2,
The resin foam composite, wherein the resin foam layer has a closed cell structure or a semi-continuous semi-independent cell structure.

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