WO2014168036A1

WO2014168036A1 - Resin foam composite

Info

Publication number: WO2014168036A1
Application number: PCT/JP2014/059400
Authority: WO
Inventors: 畑中逸大; 齋藤誠; 加藤和通; 山成悠介
Original assignee: 日東電工株式会社
Priority date: 2013-04-10
Filing date: 2014-03-31
Publication date: 2014-10-16
Also published as: TW201500201A; CN105121529A; KR102218808B1; JP6358825B2; KR20150140761A; JP2014218077A; CN105121529B

Abstract

Provided is a flexible resin foam composite that can be used for design gaps, which have become extremely narrow as electronics have become thinner. A resin foam composite obtained by laminating a resin foam layer and an adhesive layer, wherein the apparent density of the resin foam layer is 0.03-0.30 g/cm³, the compressive stress during 50% compression is 5.0 N/cm² or lower, the thickness of the adhesive layer is 0.0005 mm-0.06 mm, and the total thickness of the resin foam composite is 0.35 mm or less. The ratio of the thickness of the resin foam layer and the thickness of the adhesive layer (thickness of resin foam layer/thickness of adhesive layer) is preferably 2.1 or higher.

Description

Resin foam composite

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

Resin foams are used as sealing materials and cushioning materials for electronic devices such as mobile phones, smartphones, and tablet PCs. In particular, a resin foam composite provided with a pressure-sensitive adhesive layer is preferably used in order to simplify the alignment during the bonding operation. In recent years, the area of resin foam composites used as sealing materials and cushioning materials has become smaller along with the downsizing of electronic devices and the enlargement of screens. There is a demand for flexibility to exhibit buffering properties. Electronic devices are also being made thinner, and resin foam composites are also required to be thinner.

As a thin resin foam, there is known a foam sheet obtained by a method in which a compression treatment or a stretching treatment is performed during foaming or in a later step or a method in which a coating treatment is performed after foaming (for example, Patent Document 1, Patent Document 2). However, the foamed sheet has a problem that it is difficult to increase the expansion ratio, and when the compression is performed such that the repulsion force at 25% compression (repulsion stress at 25% compression) exceeds 3 N / cm ^2. There was a problem that the repulsive force of.

In recent years, with the thinning of mobile devices, the design gap (gap, gap) in which resin foam is used becomes very narrow (for example, a gap of 0.1 mm or less), and design tolerances are taken into account for resin foam composites. Thus, it is not uncommon to use compressed to 50% or more. However, when using a resin foam composite that has a large repulsive force when compressed in a very narrow design gap of such a display device, for example, display unevenness occurs in the liquid crystal of the display unit due to the high repulsive force, Display failure may occur.

Also, it is conceivable to reduce the repulsive force by reducing the compression rate using a thin resin foam. However, as described above, in the case of a resin foam composite in which a resin foam is provided with a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer itself is not compressed. Therefore, if a thick pressure-sensitive adhesive layer is used, the repulsive force increases and display unevenness occurs. There was a thing.

JP 2009-190195 A JP 2010-1407

Therefore, an object of the present invention is to provide a flexible resin foam composite that can be used for a design gap that has become very narrow as the electronic equipment is made thinner. Moreover, it is providing the resin foam composite which can make the position alignment simple at the time of bonding operation | work.

As a result of intensive studies to achieve the above object, the present inventors have used a specific resin foam layer, and by making the thickness of the resin foam composite and the thickness of the adhesive layer predetermined, It was found that a resin foam composite capable of simplifying the alignment while suppressing the rise can be obtained. The present invention has been 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, and the apparent density of the resin foam layer is 0.03 to 0.30 g / cm ³ , 50% compression. Resin foam composite in which the compression stress at the time is 5.0 N / cm ² or less, 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 I will provide a.

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

The pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive layer.

Further, in the resin foam composite, the resin constituting the resin foam layer is preferably a thermoplastic resin, and more preferably a polyolefin resin.

Further, the resin foam composite preferably has a surface layer formed by heat melting treatment on at least one surface of the resin foam layer.

In the resin foam composite, the resin foam layer is preferably formed through a process 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.

Furthermore, in the resin foam composite, the high-pressure gas is more preferably in a supercritical state.

In the resin foam composite, the resin foam layer preferably has a closed cell structure or a semi-continuous semi-closed 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 this invention is used with respect to the very narrow gap of a liquid crystal display device, for example, it does not cause a display nonuniformity or a display defect. Moreover, the resin foam composite of this invention can simplify the positioning especially at the time of bonding operation.

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

The resin foam composite of this invention has at least the structure which laminated | stacked the resin foam layer and the adhesive layer (pressure-sensitive adhesive layer).

[Resin foam layer]
The resin foam layer in the resin foam composite of the present invention is a layer composed of a resin foam. The resin foam is obtained by foaming a resin composition.

The resin foam layer has an apparent density of 0.03 g / cm ³ to 0.30 g / cm ³ . In the resin foam layer, since the apparent density is 0.03 g / cm ³ or more, the strength can be secured, and since the apparent density is 0.30 g / cm ³ or less, good flexibility can be obtained. it can. The apparent density of the resin foam layer is preferably ^{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 and pressure of the foaming agent impregnated in the resin composition.

In the said resin foam layer, the compressive stress at the time of 50% compression is 5.0 N / cm < ² > or less. In the said resin foam layer, since the compressive stress at the time of 50% compression is 5.0 N / cm < ² > or less, favorable softness | flexibility is obtained and the repulsive force at the time of compression can be made small. The compressive stress at the time of 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. Also it is preferably 0.1 N / cm ² or more, and more preferably 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 foaming ratio and the degree of openness depending on the temperature at the time of foaming. The degree of open cell refers to the degree to which the closed cell structure is continuous (open cell) when the resin composition is foamed.

The compressive stress at the time of 50% compression is the stress (N) measured when compressed by 50% of the initial thickness in the thickness direction of the resin foam layer based on JIS K 6767, and the stress is expressed in units. It is determined by converting per area (cm ² ).

The resin foam layer in the resin foam composite of the present invention can be 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 the polyolefin resin composition containing polyolefin resin. That is, the resin foam layer in the resin foam composite of the present invention is preferably a polyolefin resin foam layer. In addition to the resin, the above resin composition may contain other components and additives. Moreover, the said resin, said other component, said additive, etc. may be used individually or in combination of 2 or more types.

In addition, although content of resin in the said resin composition is not specifically limited, 50 mass% or more is preferable with respect to the resin composition whole quantity (100 mass%), More preferably, it is 60 mass% or more.

The cell structure (cell structure) of the resin foam layer in the resin foam composite of the present invention is not particularly limited, but is closed cell structure, semi-continuous semi-closed cell structure (closed cell structure and open cell structure are mixed) The ratio is not particularly limited), and a semi-continuous semi-closed cell structure is more preferable. The ratio of the closed cell structure part of the resin foam layer is not particularly limited, but is preferably 40% or less with respect to the total volume (100%) of the resin foam layer from the viewpoint of flexibility. More preferably, it is 30% or less. The cell structure can be controlled, for example, by adjusting the expansion ratio by the amount and pressure of the foaming agent impregnated in 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 is preferably 10 μm to 150 μm, more preferably 20 μm to 120 μm, and more preferably 30 μm to 80 μm. Is more preferable. When the average cell diameter of the resin foam layer is 10 μm or more, impact absorbability (cushioning property) is easily improved. When the average cell diameter of the resin foam layer is 150 μm or less, the foam has a finer cell structure, so that it can be used more easily for minute clearances, and the dust resistance is easily improved.

The resin that is the material of the resin foam layer in the resin foam composite of the present invention is not particularly limited, but is preferably a thermoplastic resin (thermoplastic polymer). In other words, the resin foam layer in the resin foam composite of the present invention is preferably obtained by foaming a thermoplastic resin composition containing at least a thermoplastic resin. The thermoplastic resin (thermoplastic polymer) that is the material of the resin foam layer is not particularly limited as long as it is a polymer exhibiting thermoplasticity and can be impregnated with a 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 copolymers (ABS resins); 6-nylon, 66-nylon, 12- Polyamide resins such as 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 Resins; polycarbonates such as bisphenol A-based polycarbonates; polyacetals; polyphenylene sulfides. A thermoplastic resin can be used individually or in combination of 2 or more types. In addition, when a thermoplastic resin is a copolymer, the copolymer of any form of a random copolymer and a block copolymer may be sufficient.

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

The polyolefin resin may be a homopolymer (homopolymer) or a copolymer (copolymer) containing two or more monomers. When the polyolefin resin is a copolymer, it may be a random copolymer or a block copolymer. One type of polymer may be sufficient as the said polyolefin resin, and what combined 2 or more types of polymers may be sufficient as it.

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

Examples of the α-olefin include α-olefins having 2 to 8 carbon atoms (for example, ethylene, propylene, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, heptene-1, Octene-1). The α-olefin may be used alone or in combination of two or more.

Examples of monomer components other than the α-olefin include ethylenically unsaturated monomers such as vinyl acetate, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, and vinyl alcohol. 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), a copolymer of ethylene and propylene, and α- other than ethylene and ethylene. Copolymers of olefins, copolymers of propylene and α-olefins other than propylene, copolymers of ethylene and propylene and ethylene and α-olefins other than propylene, propylene and ethylenically unsaturated monomers A copolymer etc. are mentioned.

From the viewpoint of heat resistance, the polyolefin resin is preferably 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. That is, examples of the polyolefin resin include polypropylene 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.

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

In addition to the thermoplastic resin, the thermoplastic resin composition may contain “rubber and / or thermoplastic elastomer” as other components.

The rubber is not particularly limited, and examples thereof include natural or synthetic rubber such as natural rubber, polyisobutylene, isoprene rubber, chloroprene rubber, butyl rubber, and nitrile butyl rubber. The said rubber | gum may be used individually or in combination of 2 or more types.

The thermoplastic elastomer is not particularly limited. For example, thermoplastics such as ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, polybutene, polyisobutylene, chlorinated polyethylene, etc. Olefin-based elastomers; thermoplastic styrene-based elastomers such as styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers, styrene-isoprene-butadiene-styrene copolymers, and their hydrogenated polymers; thermoplastic polyesters Elastomers; thermoplastic polyurethane elastomers; thermoplastic acrylic elastomers and the like. The said thermoplastic elastomer may be used individually or in combination of 2 or more types.

The content of the “rubber and / or thermoplastic elastomer” in the thermoplastic resin composition is not particularly limited, but is 0% by mass to 70% with respect to the total amount of the thermoplastic resin composition (100% by mass). % By mass is preferable, more preferably 20% by mass to 60% by mass, and still more preferably 20% by mass to 50% by mass.

Furthermore, 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 softening agent” as other components. Good. The above-mentioned “mixture (composition) containing rubber and / or thermoplastic elastomer and softener” may contain additives as necessary.

Examples of the “mixture (composition) containing rubber and / or thermoplastic elastomer and softening agent” include, for example, a mixture containing at least rubber, a thermoplastic elastomer and a softening agent, a mixture containing at least rubber and a softening agent, Examples thereof include a mixture containing at least a thermoplastic elastomer and a softening agent. Among these, “a mixture composed of only rubber and / or thermoplastic elastomer and softener” is preferable.

The rubber in the “mixture containing a rubber and / or thermoplastic elastomer and a softening agent” is not particularly limited, but the rubber exemplified as the rubber of the “rubber and / or thermoplastic elastomer” is preferably exemplified. In addition, this rubber | gum may be used individually or in combination of 2 or more types.

Further, the rubber and / or thermoplastic elastomer in the above-mentioned “rubber and / or thermoplastic elastomer and mixture containing softener” is not particularly limited as long as it can be foamed. And / or thermoplastic elastomer ”. Among these, the thermoplastic elastomer exemplified as the thermoplastic elastomer of the “rubber and / or thermoplastic elastomer” is preferable. In addition, this thermoplastic elastomer may be used individually or in combination of 2 or more types.

In particular, in a polyolefin resin composition using a polyolefin resin as a thermoplastic resin, the “rubber and / or thermoplastic elastomer” in the “mixture containing a rubber and / or a thermoplastic elastomer and a softener” is an olefin. An olefin elastomer having a structure in which a polyolefin component and an olefin rubber component are microphase-separated is particularly preferable. Examples of the olefin elastomer having a structure in which the polyolefin component and the olefin rubber component are microphase-separated include an elastomer comprising polypropylene resin (PP) and ethylene-propylene rubber (EPM) or ethylene-propylene-diene rubber (EPDM). Is preferably exemplified. The mass ratio of the polyolefin component to the olefin rubber component is preferably polyolefin component / olefin rubber = 90/10 to 10/90, more preferably 80/20 to 20 from the viewpoint of compatibility. / 80.

The above-mentioned softener is not particularly limited, but a softener generally used for rubber products is preferable. By containing the softening agent, processability and flexibility can be improved.

Specific examples of the softener include petroleum oils such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt and petroleum jelly; coal tars such as coal tar and coal tar pitch; castor oil, linseed oil and rapeseed oil Fatty oils such as soybean oil and coconut oil; waxes such as tall oil, beeswax, carnauba wax and lanolin; synthetic polymer substances such as petroleum resin, coumarone indene resin and atactic polypropylene; dioctyl phthalate, dioctyl adipate, dioctyl Examples include ester compounds such as sebacate; microcrystalline wax, sub (factis), liquid polybutadiene, modified liquid polybutadiene, liquid thiocol, liquid polyisoprene, liquid polybutene, and liquid ethylene / α-olefin copolymers. Of these, paraffinic, naphthenic and aromatic mineral oils, liquid polyisoprene, liquid polybutene, and liquid ethylene / α-olefin copolymers are preferable, and liquid polyisoprene, liquid polybutene, and liquid ethylene / α-α are more preferable. It is an olefin copolymer. In addition, the said softener may be used individually or in combination of 2 or more types.

The content of the softening agent in the “mixture containing rubber and / or thermoplastic elastomer and softening agent” is not particularly limited, but is 1 part by mass with respect to 100 parts by mass of the rubber and / or thermoplastic elastomer component. Is preferably 200 parts by mass, more preferably 5 parts by mass to 100 parts by mass, and still more preferably 10 parts by mass to 50 parts by mass. In addition, when there is too much content of a softening agent, a dispersion | distribution defect may arise at the time of kneading | mixing with rubber | gum and / or a thermoplastic elastomer.

In the above “mixture containing rubber and / or thermoplastic elastomer and softener”, an additive may be added. Examples of such additives include, but are not limited to, anti-aging agents, weathering agents, ultraviolet absorbers, dispersants, plasticizers, carbon black, antistatic agents, surfactants, tension modifiers, fluidity. Examples thereof include modifiers. In addition, such an additive may be used individually or in combination of 2 or more types.

The content of the additive in the “mixture containing rubber and / or thermoplastic elastomer and softener” is not particularly limited. For example, with respect to 100 parts by mass of the rubber and / or thermoplastic elastomer component, The amount is preferably 0.01 to 100 parts by mass, more preferably 0.05 to 50 parts by mass, and still more preferably 0.1 to 30 parts by mass. In addition, it is preferable for the content to be 0.01 parts by mass or more because the effect of adding the additive is more easily exhibited.

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

The “JIS A hardness” in the “mixture containing rubber and / or thermoplastic elastomer and softener” is not particularly limited, but is preferably 30 ° to 90 °, more preferably 40 ° to 85 °. When the “JIS A hardness” is 30 ° or more, a resin foam having a high expansion ratio is easily obtained, which is preferable. Moreover, it is preferable that the “JIS A hardness” is 90 ° or less because a flexible resin foam is easily obtained. In addition, the “JIS A hardness” in this specification refers to the hardness measured based on ISO7619 (JIS K6253).

The resin composition such as the thermoplastic resin composition may contain an additive as long as the effects of the present invention are not impaired. Examples of the additives include cell nucleating agents, crystal nucleating agents, plasticizers, lubricants, colorants (pigments, dyes, etc.), ultraviolet absorbers, antioxidants, anti-aging agents, fillers, reinforcing agents, and antistatic agents. Agents, surfactants, tension modifiers, shrinkage inhibitors, fluidity modifiers, clays, vulcanizing agents, surface treatment agents, flame retardants and the like. In addition, the said additive may be used individually or in combination of 2 or more types.

From the viewpoint of obtaining a resin foam layer having a uniform and fine cell structure, the resin composition preferably contains a cell nucleating agent. For example, when the cell nucleating agent is contained in a thermoplastic resin composition, a resin foam having a uniform and fine cell structure can be easily obtained. It is preferable that an agent is included.

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, montmorillonite and other clays, carbon particles, and glass fibers. And carbon tubes. In addition, particle | grains may be used individually or in combination of 2 or more types.

In the resin composition such as the thermoplastic resin composition, the content of the cell 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 rubber and / or thermoplastic elastomer and softener”, in such a resin composition, The content of the cell nucleating agent is not particularly limited, but is the total amount of the thermoplastic resin and the “mixture (composition) containing rubber and / or thermoplastic elastomer and softener” (hereinafter referred to as “total amount of resin component”). 0.5 parts by mass to 125 parts by mass, and more preferably 1 part by mass to 120 parts by mass with respect to 100 parts by mass.

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

When the above flame retardant is contained in the resin composition, the resin foam layer becomes flame retardant and can be used for applications requiring flame resistance such as electrical or electronic equipment. For this reason, the flame retardant may be contained in resin compositions, such as the said thermoplastic resin composition.

The flame retardant may be in the form of powder or may be in a form other than powder. As the powdery flame retardant, an inorganic flame retardant is preferable. Examples of the inorganic flame retardant include bromine-based flame retardant, chlorine-based flame retardant, phosphorus-based flame retardant, antimony-based flame retardant, and non-halogen-non-antimony-based inorganic flame retardant. Here, chlorinated flame retardants and brominated flame retardants generate gas components that are harmful to the human body and corrosive to equipment during combustion, and phosphorous flame retardants and antimony flame retardants are There are problems such as toxicity and explosiveness. Therefore, as the inorganic flame retardant, a non-halogen-nonantimony inorganic flame retardant is preferable. Examples of the non-halogen-nonantimony inorganic flame retardant include hydrated metal compounds such as aluminum hydroxide, magnesium hydroxide, magnesium oxide / nickel oxide hydrate, magnesium oxide / zinc oxide hydrate, and the like. . The hydrated metal oxide may be surface treated. In addition, a flame retardant may be used individually or in combination of 2 or more types.

The flame retardant preferably 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. Examples of the flame retardant having a function as a cell nucleating agent include magnesium hydroxide and aluminum hydroxide.

In the resin composition 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 to 150 parts by mass, more preferably 60 parts with respect to 100 parts by mass of the total resin component. Parts by mass to 120 parts by mass. If the amount of the flame retardant used is too small, the flame retardant effect is reduced. Conversely, if the amount is too large, it is difficult to obtain a highly foamed foam.

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

The lubricant is not particularly limited. For example, hydrocarbon lubricants such as liquid paraffin, paraffin wax, microwax and polyethylene wax; fatty acid lubricants such as stearic acid, behenic acid and 12-hydroxystearic acid; butyl stearate , Ester-based lubricants such as stearic acid monoglyceride, pentaerythritol tetrastearate, hydrogenated castor oil, stearyl stearate, and the like. In addition, a lubricant may be used alone or in combination of two or more.

In the resin composition 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 rubber and / or thermoplastic elastomer and softener”, in such a resin composition, The content of the lubricant is not particularly limited, but is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the total resin component. . When the addition amount exceeds 10 parts by mass, the fluidity may become too high, and the expansion ratio may decrease. On the other hand, if it is less than 0.1 parts by mass, the fluidity cannot be improved, the stretchability at the time of foaming is lowered, and the foaming ratio may be lowered.

The shrinkage-preventing agent has a function of effectively suppressing permeation of the foaming agent gas by forming a molecular film on the surface of the foam film. For this reason, the said resin composition, such as the said thermoplastic resin composition, may contain the shrinkage-preventing agent from the point which obtains the cell structure of the high expansion ratio in the said resin foam layer. The shrinkage-preventing agent is not particularly limited as long as it has an effect of suppressing the permeation of blowing agent gas. For example, fatty acid metal salts (for example, fatty acid such as stearic acid, behenic acid, 12-hydroxystearic acid) A salt of aluminum, calcium, magnesium, lithium, barium, zinc, lead, etc.); fatty acid amide [fatty acid amide (monoamide or bisamide) of about 12 to 38 carbon atoms (preferably about 12 to 22 carbon atoms) Bisamide is preferably used to obtain a fine cell structure.), For example, stearic acid amide, oleic acid amide, erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, lauric acid bisamide, etc. ] Etc. are mentioned. Such anti-shrinkage agents can be used alone or in combination of two or more.

In the resin composition such as the thermoplastic resin composition, the addition 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 rubber and / or thermoplastic elastomer and softener”, in such a resin composition, The addition amount of the shrinkage inhibitor is not particularly limited, but is preferably 0.5 to 10 parts by mass, more preferably 0.7 to 10 parts by mass with respect to 100 parts by mass of the total amount of resin components. The amount is 8 parts by mass, more preferably 1 part by mass to 6 parts by mass. When the addition amount exceeds 10 parts by mass, gas efficiency is lowered in the cell growth process, so that a cell with a small cell diameter can be obtained, but the number of unfoamed portions increases, and the expansion ratio may decrease. On the other hand, if the amount is less than 0.5 parts by mass, the coating film is not sufficiently formed, gas escape occurs at the time of foaming, shrinkage occurs, and foaming ratio may decrease.

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

The method for producing the resin composition is not particularly limited. For example, the thermoplastic resin composition is not particularly limited, but may be prepared by kneading the thermoplastic resin, other components as necessary, and additives added as necessary. Alternatively, it may be obtained by kneading and extruding with a known melt-kneading extruder such as a uniaxial (single-axis) kneading extruder or a biaxial kneading extruder.

The form of the resin composition such as the thermoplastic resin composition is not particularly limited. For example, a strand shape; a sheet shape; a flat plate shape; a strand shape that is water-cooled or air-cooled and cut into an appropriate length. Is mentioned. Especially, it is preferable to knead | mix and pelletize from a point 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, It is preferable to heat-melt the surface to form a surface layer. For example, it is preferably formed by foaming the thermoplastic resin composition (for example, the polyolefin resin composition). In particular, it is preferable to foam the thermoplastic resin composition (for example, the polyolefin resin composition) and then heat-melt the surface to form a surface layer.

The method of foaming a resin composition such as the thermoplastic resin composition (for example, the polyolefin resin composition) is not particularly limited, and examples thereof include a physical foaming method and a chemical foaming method. The physical foaming method is a method of forming cells (bubbles) by impregnating (dispersing) a low boiling point liquid (foaming agent) in a resin composition and then volatilizing the foaming agent. Moreover, the said chemical foaming method is a method of forming a cell with the gas produced by the thermal decomposition of the compound added to the resin composition. Among these, the physical foaming method is preferable from the viewpoint of avoiding contamination of the resin foam layer and the ease of obtaining a fine and uniform cell structure, and the physical foaming method using a high-pressure gas as a foaming agent is more preferable. Therefore, the resin foam layer in the resin foam composite of the present invention is particularly suitable for a resin composition such as the thermoplastic resin composition (for example, the polyolefin resin composition) or the like with a high-pressure gas (for example, described later). It is preferably formed by foaming after impregnating with an inert gas.

The inert gas is not particularly limited, and examples thereof include carbon dioxide, nitrogen gas, air, helium, and argon. In particular, the inert gas is preferably carbon dioxide from the viewpoint that the amount of impregnation into the resin composition such as the thermoplastic resin composition is large and the impregnation rate is high. In addition, the said inert gas may be used individually or in combination of 2 or more types.

The mixing amount (content, impregnation amount) of the foaming agent is not particularly limited, but is 2% by mass to 10% by mass with respect to the total weight (100% by mass) of the resin composition such as the thermoplastic resin composition. Is preferred. By setting it within the above range, the apparent density of the resin foam layer in the resin foam composite of the present invention can be easily set within a predetermined range.

The above-mentioned inert gas is preferably in a supercritical state at the time of impregnation from the viewpoint of increasing the impregnation rate into a resin composition such as a thermoplastic resin composition. For example, the resin foam layer in the resin foam composite of the present invention may be formed by foaming the thermoplastic resin composition (for example, the polyolefin resin composition) using a supercritical fluid. preferable. When the inert gas is a supercritical fluid (supercritical state), the solubility in a resin composition such as a thermoplastic resin composition increases, and high concentration impregnation (mixing) is possible. In addition, since it is possible to impregnate at a high concentration, when the pressure is drastically lowered after the impregnation, the generation of bubble nuclei increases, and the density of bubbles formed by the growth of the bubble nuclei has a porosity. Even if they are the same, they become larger, so that fine bubbles can be obtained. Carbon dioxide has a critical temperature of 31 ° C. and a critical pressure of 7.4 MPa.

As a physical foaming method using a gas as a foaming agent, a resin composition such as a thermoplastic resin composition is impregnated with a high-pressure gas (for example, an inert gas) and then reduced in pressure (for example, to atmospheric pressure). A method of forming by foaming through (the step of releasing pressure) is preferable. Specifically, an unfoamed molded product is obtained by molding a resin composition such as a thermoplastic resin composition, and the unfoamed molded product is impregnated with a high-pressure gas, and then reduced in pressure (for example, up to atmospheric pressure). A method of forming by foaming through a step of performing, or impregnating a molten resin composition such as a thermoplastic resin composition with a gas (for example, an inert gas) under a pressurized state, and then reducing the pressure (for example, And a method of forming by foaming and forming by molding.

That is, when forming the resin foam layer in the resin foam composite of the present invention, a resin composition such as the thermoplastic resin composition (for example, the polyolefin resin composition) is appropriately used in a sheet form or the like. After forming into a non-foamed resin molded body (unfoamed molded product), the unfoamed resin molded body is impregnated with a high-pressure gas and foamed by releasing the pressure. Alternatively, a resin composition such as the above-mentioned thermoplastic resin composition may be kneaded with a high-pressure gas under high-pressure conditions, and may be molded in a continuous manner in which the pressure is released and molding and foaming are performed simultaneously.

In the batch method, the method for forming the unfoamed resin molded body is not particularly limited. For example, a resin composition such as a thermoplastic resin composition is used using an extruder such as a single screw extruder or a twin screw extruder. The resin composition such as a thermoplastic resin composition is uniformly kneaded using a kneader equipped with blades such as a roller, a cam, a kneader, and a banbari type, and a hot plate press or the like is used. And a method of press molding to a predetermined thickness using a resin composition such as a thermoplastic resin composition using an injection molding machine. The shape of the unfoamed resin molded body is not particularly limited, and examples thereof include a sheet shape, a roll shape, and a plate shape. In the above batch method, an unfoamed resin molded body is molded from a resin composition such as a thermoplastic resin composition by an appropriate method for obtaining an unfoamed resin molded body having a desired shape and thickness.

In the above batch method, a non-foamed resin molded product is placed in a pressure-resistant container, a high-pressure gas is injected (introduced and mixed), and the non-foamed resin molded product is impregnated with gas. When the pressure is released, the pressure is released (usually up to atmospheric pressure), and a bubble structure is formed through a decompression step for generating bubble nuclei in the unfoamed resin molded body.

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

In the batch method or the continuous method, a heating step for growing bubble nuclei by heating may be provided as necessary. Note that bubble nuclei may be grown at room temperature without providing a heating step. Furthermore, after the bubbles are grown, if necessary, the shape may be fixed rapidly by cooling with cold water or the like. The high-pressure gas may be introduced continuously or discontinuously. The heating method for growing the cell nuclei is not particularly limited, and examples thereof include known or conventional methods such as a water bath, an oil bath, a hot roll, a hot air oven, far infrared rays, near infrared rays, and microwaves.

In the batch type gas impregnation step and the continuous type kneading impregnation step, the pressure when impregnating the gas is appropriately selected in consideration of the type of gas, operability, etc., for example, 5 MPa or more (for example, 5 MPa to 100 MPa), more preferably 7 MPa or more (for example, 7 MPa to 100 MPa). That is, the resin composition such as the thermoplastic resin composition is preferably impregnated with a gas having a pressure of 5 MPa or more (for example, a pressure of 5 MPa to 100 MPa), and an inert gas having a pressure of 7 MPa or more (for example, a pressure of 7 MPa to 100 MPa). It is more preferable to impregnate. When the gas pressure is lower than 5 MPa, the bubble growth at the time of foaming is remarkable, the cell becomes too large, and disadvantages such as a decrease in the dustproof effect are likely 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 when the pressure is high, and the number of bubble nuclei formed by decreasing the bubble nucleus formation rate is reduced. This is because the bubble diameter is extremely increased. Further, in the pressure region lower than 5 MPa, the cell diameter and the bubble density are greatly changed only by slightly changing the impregnation pressure, so that it is difficult to control the cell diameter and the bubble density.

In addition, in the gas impregnation step in the batch method and the kneading impregnation step in the continuous method, the temperature at which the gas is impregnated (impregnation temperature) varies depending on the type of gas and resin used and can be selected in a wide range. In consideration of the above, it is preferably 10 ° C. to 350 ° C. More specifically, the impregnation temperature in the batch method is preferably 10 ° C to 250 ° C, more preferably 40 ° C to 240 ° C, and further preferably 60 ° C to 230 ° C. In the continuous method, the impregnation temperature is preferably 60 ° C. to 350 ° C., more preferably 100 ° C. to 320 ° C., and further preferably 150 ° C. to 300 ° C. When carbon dioxide is used as the high-pressure gas, the temperature during impregnation (impregnation temperature) is preferably 32 ° C. or higher (particularly 40 ° C. or higher) in order to maintain a supercritical state. In addition, after the impregnation with the gas and before foam molding, the resin composition such as the thermoplastic resin composition impregnated with the gas is cooled to a temperature suitable for foam molding (for example, 150 ° C. to 190 ° C.). Also good.

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

When a heating step is provided for growing bubble nuclei, the heating temperature is preferably 40 ° C. to 250 ° C., and more preferably 60 ° C. to 250 ° C., for example.

In addition, the cell structure and apparent density of the resin foam layer in the resin foam composite of the present invention are, for example, when foam-molding a resin composition such as a thermoplastic resin composition, depending on the type of resin constituting the resin foam layer. It is adjusted by selecting a foaming method and foaming conditions (for example, the type and amount of a foaming agent, the temperature, pressure and time during foaming).

The resin foam layer in the resin foam composite of the present invention is particularly preferably formed by foaming a resin composition such as a thermoplastic resin composition and then slicing the surface. Specifically, it is formed by foaming a resin composition such as the thermoplastic resin composition to obtain a foam (sheet-like foam A), and then slicing the surfaces on both sides of the foam. It is preferable. The sheet-like foam A (foam obtained by foaming a resin composition such as the thermoplastic resin composition) is a layered portion having a higher density than the inside (compared to the inside) near the surface. It often has a layered portion having a low expansion ratio, a skin layer). According to the slicing process, this layered portion (skin layer) can be removed, and the opening can be provided by exposing the internal cell structure to the foam surface. Moreover, the resin foam layer of arbitrary thickness can be obtained with sufficient thickness precision by slicing.

As the slicing process, the skin layer on the surface can be peeled off one surface at a time using a continuous slicing device (slice line) as shown in FIG. In other words, an opening is formed on both surfaces of a long foam original fabric (for example, sheet-like foam A) by passing it twice through a continuous slicing device in order to remove the skin layer on the surface.

The resin foam layer used in the present invention is preferably formed by foaming the resin composition and further heat-melting the surface to form a surface layer. 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-like foam), the surface layer is obtained by subjecting the surface of the foam to heat-melting treatment. Is preferably formed. Thus, the thickness of the resin foam layer can be adjusted to be thin by melting the surface in the thickness direction. Furthermore, it is possible to obtain a long resin foam layer easily and continuously by increasing the tensile strength in the length direction while minimizing the decrease in flexibility and suppressing the occurrence of breakage and tearing. I get out. Furthermore, since the foamed portion returns to the non-foamed state (bulk), the original surface roughness (thickness error) is reduced and the thickness accuracy is improved. The occurrence of winding wrinkles) can be suppressed. In the present specification, a sheet-like foam obtained by foaming the resin composition and before the heat-melting treatment may be referred to as a “foam structure”.

The heat-melting treatment is not particularly limited, but it suppresses the generation of wrinkles during winding, particularly the generation of wrinkles during high-speed winding, and obtains better winding stability and improves the thickness accuracy. In view of the above, it is preferable to apply the entire foam structure to at least one surface. That is, when the resin foam layer used in the present invention is formed by foaming the thermoplastic resin composition and then subjecting the surface to heat-melting treatment, foaming is performed by foaming the thermoplastic resin composition. After obtaining the structure, it is preferable to form by heating and melting one or both sides of the foam structure. In addition, the same surface may be heat-melted twice or more.
Furthermore, you may heat-melt as a resin foam composite which laminated | stacked the adhesive layer mentioned later. After forming the resin foam composite in which the foam structure and the pressure-sensitive adhesive layer are laminated, the foam structure may be heat-melted to form a surface layer.

The heating and melting treatment is not particularly limited, and examples thereof include a press treatment using a hot roll, a laser irradiation treatment, a contact melting treatment on a heated roll, and a flame treatment. In the case of press treatment with a hot roll, the treatment can be suitably performed using a thermal laminator or the like. Examples of the material of the roll include rubber, metal, and fluorine-based resin (for example, Teflon (registered trademark)).

The temperature during the heat-melting treatment is not particularly limited, but is 15 ° C. lower than the softening point or melting point of the resin included in the foam structure (more preferably, 12 degrees lower than the softening point or melting point of the resin included in the foam structure). Preferably, the temperature is 20 ° C. higher than the softening point or melting point of the resin contained in the foam structure (more preferably, 10 ° C. higher than the softening point or melting point of the resin contained in the foam structure). It is preferable that
Further, when a heat-melting treatment is performed as a resin foam composite in which an adhesive layer is laminated, the temperature during the heat-melting treatment is not particularly limited, but is 40 ° C. or higher than the softening point or melting point of the resin. It is preferable.
For example, a temperature that is 15 ° C. lower than the softening point or melting point of a thermoplastic resin (for example, the above-mentioned polyolefin resin) included in the foam structure (more preferably 12 from the softening point or melting point of the thermoplastic resin included in the foam structure). Preferably, the temperature is 20 ° C. higher than the softening point or melting point of the thermoplastic resin contained in the foam structure (more preferably from the softening point or melting point of the thermoplastic resin contained in the foam structure). The temperature is preferably 10 ° C. or higher). It is preferable that the temperature during the heat-melting treatment is higher than a softening point or a temperature 15 ° C. lower than the melting point of a resin such as a thermoplastic resin constituting the heat-melting treatment because the heat-melting treatment can be performed efficiently. Moreover, it is preferable that the temperature during the heat-melting treatment is lower than a temperature higher by 20 ° C. than the softening point or melting point of a resin such as a thermoplastic resin, which can be suppressed from shrinking and generating wrinkles.

Further, the treatment time of the heat-melting treatment is preferably about 0.1 seconds to 10 seconds, and preferably about 0.5 seconds to 7 seconds, although it depends on the treatment temperature. If the time is too short, melting may not proceed, and if the time is too long, shrinkage may cause wrinkles.

In particular, the above heat-melting treatment suppresses the generation of wrinkles during winding, particularly the generation of wrinkles during winding at high speed, and obtains better winding stability and further improves the thickness accuracy. In view of this, it is preferable to use a heat-melting treatment apparatus that can adjust a gap (gap, interval) through which the foam structure passes.

As such a heat-melting processing apparatus, for example, a continuous processing apparatus having a heating roll (thermal dielectric roll) 23 capable of adjusting the gap shown in FIG. That is, the foamed structure fed from the feed roll 21 is passed through the gap between the heating roll (thermal dielectric roll) 23 and the cooling roll 24, and contact melting processing is performed by the thermal roll (thermal dielectric roll) 23, and the thermal melting processing is performed. The resin foam layer on which the surface layer is formed is wound with a winding roll 25.

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 has excellent winding stability (winding stability). For this reason, a wide and long long roll can be obtained. Moreover, the resin foam which comprises the said resin foam layer is thin, and can make thickness accuracy high.

When the surface layer is provided on the resin foam layer in the resin foam composite of the present invention, the surface coverage is preferably 40% or more. That is, the resin foam layer preferably 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 indicating the ratio of non-porous portions (portions that are not pores, bulk, non-foamed portions) existing on the surface, and is defined by the following formula (1). If the surface coverage is 100%, there will be no holes on the surface.
Surface coverage (%) = [(surface area) − (area of pores 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 the thickness of the resin foam composite is designed to be 0.35 mm or less, but is 0.03 mm to 0.34 mm. The thickness is preferably 0.04 mm to 0.28 mm, and more preferably 0.05 mm to 0.20 mm. When the thickness of the resin foam layer is within the above range, there is an advantage that the resin foam layer can be compressed and inserted into a narrow gap while maintaining high shock absorption. On the other hand, if the thickness of the resin foam is less than 0.03 mm, the shock absorption, which is the main application, may be reduced. On the other hand, if the thickness of the resin foam exceeds 0.34 mm, it is inserted into a narrow gap of 0.1 mm. There are cases where it is impossible. 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 | required by following formula (2) of the resin foam layer in the resin foam composite of this invention is not specifically limited, It is preferable that it is 25% or less, More preferably, it is 15% or less, More preferably, it is 10% or less. It is. When the “value obtained from the formula (2)” is within 25%, the generation of wrinkles at the time of winding, particularly the generation of wrinkles at the time of winding at high speed, is suppressed, and better winding stability is obtained. Can be preferable. Moreover, since high thickness precision can be obtained, generation | occurrence | production of a wrinkle can be prevented at the time of bonding with an adhesive layer, and it is preferable. In the present specification, the high speed during winding refers to a speed of 10 to 40 m / min, for example.
(Thickness tolerance) / (median thickness) × 100 (2)
Thickness tolerance: The thickness is measured every 10 mm in the width direction from one end to the other at one point in the length direction, and one point at a point moved 1 m in the length direction from one point in the length direction. The thickness is measured every 10 mm in the width direction from the end to the other end, and the difference between the maximum value and the minimum value of all the measured values obtained.
Median thickness: Measured thickness every 10 mm in the width direction from one end to the other at one point in the length direction, and further moved 1 m in the length direction from one point in the length direction. The thickness is measured every 10 mm in the width direction from one end portion to the other end portion, and is a value located in the center when all the obtained measurement values are arranged in ascending order.

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, wound up, or in a roll shape (rolled body). .

In the resin foam layer in the resin foam composite of the present invention, the width of the resin foam used for the resin foam layer is not particularly limited, but is 300 mm or more (for example, 300 mm to 1500 mm). Preferably, it is 400 mm or more (for example, 400 mm to 1200 mm), more preferably 500 mm or more (for example, 500 mm to 1000 mm). Since the said width | variety is 300 mm or more, design and processing with a high freedom degree can be performed and it is preferable.

Moreover, 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 made of a sheet-like material, the length is not particularly limited, but is 5 m or more (for example, 5 m To 1000 m), preferably 30 m or more (for example, 30 m to 500 m), and more preferably 50 m or more (for example, 50 m to 300 m).

[Adhesive layer]
In the resin foam composite of the present invention, the pressure-sensitive adhesive layer refers to a layered material that provides an adhesive surface for the resin foam layer and an adhesive surface for an adherend. For example, the pressure-sensitive adhesive layer in the resin foam composite of the present invention includes a base material-less double-sided pressure-sensitive adhesive sheet (a pressure-sensitive adhesive sheet composed of only one pressure-sensitive adhesive layer), a double-sided pressure-sensitive adhesive sheet with a base material (both sides of the base material) The pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer), a pressure-sensitive adhesive layer with a substrate described later, and the like are included.

The pressure-sensitive adhesive layer in the resin foam composite of the present invention is not particularly limited. For example, acrylic pressure-sensitive adhesive, rubber pressure-sensitive adhesive (natural rubber pressure-sensitive adhesive, synthetic rubber pressure-sensitive adhesive, etc.), silicone pressure-sensitive adhesive, polyester It can be formed from a pressure-sensitive adhesive such as a pressure-sensitive adhesive, urethane pressure-sensitive adhesive, polyamide-based pressure-sensitive adhesive, epoxy-based pressure-sensitive adhesive, vinyl alkyl ether-based pressure-sensitive adhesive, or fluorine-based pressure-sensitive adhesive. In particular, an acrylic pressure-sensitive adhesive is preferably used because it has high adhesive properties and heat resistance. The pressure-sensitive adhesives may be used alone or in combination of two or more. The pressure-sensitive adhesive may be any form of pressure-sensitive adhesive such as an emulsion-based pressure-sensitive adhesive, a solvent-based pressure-sensitive adhesive, a hot-melt pressure-sensitive adhesive, an oligomer-based pressure-sensitive adhesive, or a solid-based pressure-sensitive adhesive.

In particular, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer in the resin foam composite of the present invention is preferably an acrylic pressure-sensitive adhesive because of its high transparency and excellent heat resistance and light resistance. That is, the pressure-sensitive adhesive layer in the resin foam composite of the present invention is preferably an acrylic pressure-sensitive adhesive layer.

The pressure-sensitive adhesive contains a base polymer and, as necessary, appropriate 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 has an acrylic polymer as a pressure-sensitive adhesive component (base polymer) or a main agent, and if necessary, a crosslinking agent, a tackifier, a softener, a plasticizer, a filler, an anti-aging agent. And appropriate additives such as colorants.

In the acrylic pressure-sensitive adhesive, in the acrylic polymer, a monomer that has (meth) acrylic acid alkyl ester as a main monomer component and can be copolymerized with the (meth) alkyl ester, if necessary. (Copolymerizable monomer) is preferably used as the other monomer component. Examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth ) Isobutyl 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, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, (meth) acrylic acid Undecyl, dodecyl (meth) acrylate, tridecyl (meth) acrylate, Carbons such as tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate (Meth) acrylic acid alkyl ester having a linear or branched alkyl group having a number of 1 to 20 (sometimes referred to as “(meth) acrylic acid C _1-20 alkyl ester”). As the above (meth) acrylic acid alkyl ester, among them, a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms (“(meth) acrylic acid C _4-18 (It may be referred to as “alkyl ester”). The said (meth) acrylic-acid alkylester can be suitably selected according to the target adhesiveness etc. Moreover, the said (meth) acrylic-acid alkylester may be used individually or in combination of 2 or more types.

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 acetate, etc. Vinyl esters; vinyl chloride; amide group-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, N, N-dimethyl (meth) acrylamide; hydroxyl such as hydroxyalkyl (meth) acrylate and glycerin dimethacrylate Group-containing monomer; ) Amino group-containing monomers such as aminoethyl acrylate and (meth) acryloylmorpholine; Imido group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; Glycidyl (meth) acrylate, Methyl glycidyl (meth) acrylate, etc. Epoxy group-containing monomer; isocyanate group-containing monomer 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) acrylate, 1,6- Multifunctional copolymerizable monomers such as hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, divinylbenzene Functional monomers) and the like. The copolymerizable monomers may be used alone or in combination of two or more. Suitable examples of the copolymerizable monomer include a modifying monomer having a functional group such as a carboxyl group.

The base polymer in the pressure-sensitive adhesive can be prepared by a conventional 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, or an ultraviolet irradiation polymerization method.

The pressure-sensitive adhesive layer can be formed by using a known or conventional forming method. For example, a method of applying a pressure-sensitive adhesive on a predetermined site or surface (application method), a release film such as a release liner, Examples thereof include a method (transfer method) of applying an adhesive to form an adhesive layer and then transferring the adhesive layer onto a predetermined site or surface. In forming the pressure-sensitive adhesive layer, a known or conventional coating method (such as a casting method, a roll coater method, a reverse coater method, a doctor blade method) can be used as appropriate.

The pressure-sensitive adhesive layer in the resin foam composite of the present invention may be a single layer or a laminate. Moreover, the adhesive layer in the resin foam composite of this invention may be an adhesive layer in the adhesive layer with a base material containing a suitable base material. The pressure-sensitive adhesive layer with a substrate may be, for example, a double-sided pressure-sensitive adhesive type having pressure-sensitive adhesive layers on both sides of the substrate. In addition, when the adhesive layer in the resin foam composite of this invention is an adhesive layer in an adhesive layer with a base material, the total thickness (thickness) of the resin foam composite includes the thickness of the resin foam and the base material. And the thickness of the adhesive layer with adhesive.

That is, the resin foam composite of the present invention may be a resin foam composite in which the resin foam layer and the adhesive layer with a base material are laminated. For example, the resin foam composite of the present invention includes the resin foam layer, the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer with the base material, the base material in the pressure-sensitive adhesive layer with the base material, and the pressure-sensitive adhesive in the pressure-sensitive adhesive layer with the base material. The layers may have a configuration in which the layers are stacked in this order. In addition, this structure is corresponded to the structure by which the said resin foam layer and the adhesive layer with a double-sided adhesive type base material were laminated | stacked.

The above-mentioned adhesive layer with a substrate is provided with a substrate in which an adhesive layer made of the above-mentioned adhesive is provided on both sides of a paper-based substrate, a fiber-based substrate, a metal-based substrate, a plastic substrate such as a PET film, etc. It may be an adhesive layer. In addition, when an adhesive layer with a base material is a double-sided adhesive type, the composition of two adhesive layers may be the same, and may differ. Moreover, the thickness of two adhesive layers may be the same, and may differ.

The material of the base material in the adhesive layer with a base material is not particularly limited, but a plastic material is suitable. As such a plastic material (material of the plastic film), various engineer plastic materials are preferably exemplified. Examples of the plastic material include polyester [polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.]; olefin resin [polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer Olefin-based resin containing α-olefin as monomer component such as polymer, ethylene-vinyl acetate copolymer (EVA), etc.]; polyethersulfone (PES) (polyethersulfone); polysulfone; polyvinylchloride (PVC); Polyphenylene sulfide (PPS); amide resin [polyamide (nylon), wholly aromatic polyamide (aramid), etc.], polyimide (PI), polyamideimide, polyetherimide (PEI), polyesterimide, methacrylate tree [Polymethyl methacrylate (PMMA), etc.]; Styrenic resin [Polystyrene, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), etc.]; Polycarbonate (PC); Polyacetal; Poly Arylene ether (polyphenylene ether, etc.); polyphenylene sulfide; polyarylate; polyaryl; polyurethanes; polyether ketones [polyether ether ketone (PEEK), polyether ketone ketone, etc.]; polyacrylates [polybutyl acrylate, Polyethyl acrylate, etc.]; epoxy resins and the like. These materials (plastic materials) may be used alone or in combination of two or more.

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

In addition, the said base material may have any form of a single layer and a lamination | stacking, and does not receive the restrictions on a structure.

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. is there.

The pressure-sensitive adhesive layer may have a pressure-sensitive adhesive surface protected by a release film (separator) (for example, release paper, release film, etc.). The release film (separator) is not included in the total thickness (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. More preferably, it is 0.002 mm to 0.04 mm. 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 may not be sufficiently small, and even when the foam is compressed, it may not be smaller than the size of the gap to be applied. As a result, when trying to apply the resin foam composite to the gap, it may be difficult to use. In addition, in the resin foam composite of this invention, when the adhesive layer is an adhesive layer in an adhesive layer with a base material, the thickness of an adhesive layer means the thickness containing a base material. For example, when the pressure-sensitive adhesive layer in the resin foam composite of the present invention is a pressure-sensitive adhesive layer in a double-sided pressure-sensitive adhesive layer with a base, the thickness of the pressure-sensitive adhesive layer includes the thickness of the base and the both sides of the base And the thickness of the two pressure-sensitive adhesive layers.

[Resin foam composite]
The resin foam composite of this invention is the structure by which the said resin foam layer and the said adhesive layer were laminated | stacked. Having an adhesive layer is advantageous for fixing to the adherend and temporary fixing, and is advantageous in terms of assembly. The shape of the resin foam composite of the present invention is not particularly limited, but may be a sheet shape (film shape) or a roll shape, and is punched or cut into various shapes depending on the application. Also good.

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 the pressure-sensitive adhesive layer is provided on the resin foam layer, by adjusting the tension applied to the resin foam layer and the pressure-sensitive adhesive layer as low as possible, the thickness of the resin foam layer and the pressure-sensitive adhesive layer is very high. Even if it is thin, it does not cause wrinkles and the like, and a resin foam composite can be produced in a good state, particularly in a good appearance. The tension at the time of applying a tension for the purpose of producing a resin foam composite in a good state, particularly in a good appearance state is not particularly limited. For example, when the width of the resin foam layer and the pressure-sensitive adhesive layer is 500 mm 1 to 100N is preferable, more preferably 1 to 90N, and still more preferably 2 to 80N. 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 further preferably 4 to 160 N. For example, when a tension of 100 N or more at a width of 500 mm and a tension of 200 N or more at a width of 1000 mm is applied, if the resin foam layer and the pressure-sensitive adhesive layer are thin, the resin foam layer and the pressure-sensitive adhesive layer are stretched due to the tension. In the subsequent process, when the tension applied to the resin foam layer and the pressure-sensitive adhesive layer is removed, the resin foam layer and the pressure-sensitive adhesive layer are contracted (shrinked) from the stretched state to the original state. When the pressure-sensitive adhesive layer is provided on the resin foam layer, wrinkles or the like are likely to occur. In addition, the tension | tensile_strength which concerns on a resin foam layer and an adhesive layer is adjusted as winding tension | tensile_strength at the time of winding in roll shape, for example, when obtaining a long-shaped 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. Moreover, when the said resin foam layer has a surface layer formed by heat-melting process, the said adhesive layer may be provided in the surface which has the surface layer in the said resin foam layer, or the said resin foam layer However, it is preferably provided on the surface of the resin foam layer that does not have the surface layer. 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 an undercoat layer is provided for the purpose of improving adhesion. May be.

The total thickness (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. It is 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 function of the resin foam (for example, sealability, flexibility, shock absorption, etc.) can be exhibited. Moreover, if the total thickness (thickness) of a resin foam composite is 0.05 mm or more, it will become easy to ensure required intensity | strength.

In the resin foam composite of the present invention, the ratio of the thickness of the resin foam layer to the thickness of the pressure-sensitive adhesive layer (the thickness of the resin foam layer / the thickness of the pressure-sensitive adhesive layer) is not particularly limited. It is preferable to determine the thickness of the resin foam layer and the pressure-sensitive adhesive layer so as to be 1 or more. The ratio of the thickness of the resin foam layer to the thickness of the pressure-sensitive adhesive layer (the thickness of the resin foam layer / the thickness of the pressure-sensitive adhesive layer) is more preferably 3.0 or more, and further preferably 5.0 or more. It is. The ratio of the thickness of the resin foam layer to the thickness of the pressure-sensitive adhesive layer (the thickness of the resin foam layer / the thickness of the pressure-sensitive adhesive layer) is usually 13 or less, preferably 11 or less. If the thickness ratio is 2.1 or more, there is an advantage that the foam can also be compressed within a range of appropriate adhesive strength. That is, since the foam can be compressed while ensuring sufficient adhesive force, the resin foam composite can be suitably applied to a smaller gap.

The resin foam composite of the present invention is preferably used for the purpose of attaching (attaching) various members or parts to a predetermined site. In particular, in an electrical or electronic device, it is suitably used when attaching (attaching) a component constituting the electrical or electronic device to a predetermined part. That is, the resin foam composite of the present invention is preferably for electric or electronic equipment.

The above-mentioned various members or parts are not particularly limited, but for example, various members or parts in electrical or electronic devices are preferably mentioned. Examples of such a member or component for electric or electronic equipment include an image display member (display unit) (particularly a small image display member) mounted on an image display device such as a liquid crystal display, an electroluminescence display, or a plasma display. ), Optical members or optical parts such as cameras and lenses (particularly small cameras and lenses) that are mounted on mobile communication devices such as so-called “mobile phones” and “portable information terminals”.

More specifically, the resin foam composite of the present invention is provided around the display unit such as an LCD (liquid crystal display) or the display unit and the casing (such as an LCD (liquid crystal display)) for the purpose of dust prevention, light shielding, buffering, etc. (Window part) and can be used.

Also, the resin foam composite of the present invention is thin and flexible and can further increase the thickness accuracy. For this reason, even if the resin foam composite of the present invention is used for an electrical or electronic device in which a large number of parts and members such as a smartphone equipped with a touch panel are laminated, a high repulsive force is not generated. Display defects such as liquid crystal display unevenness in the display section are not caused.

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

[Example]
Polypropylene [melt flow rate (MFR): 0.35 g / 10 min]: 45 parts by mass, 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 with respect to 100 parts by mass of polyolefin elastomer]: 55 parts by mass, magnesium hydroxide: 10 parts by mass, carbon (trade name “Asahi # 35” manufactured by Asahi Carbon Co., Ltd.): 10 Part by mass, stearic acid monoglyceride: 1 part by mass, and fatty acid amide (lauric acid bisamide): 1.5 parts by mass were kneaded at a temperature of 200 ° C. in a twin-screw kneader manufactured by Japan Steel Works (JSW). Thereafter, it was extruded into a strand shape, cooled to water, and formed into a pellet shape. The pellets were put into a single screw extruder manufactured by Nippon Steel Works, and carbon dioxide gas was injected under an atmosphere of 220 ° C. at a pressure of 13 (12 after injection) MPa. Carbon dioxide gas was injected at a rate of 5.7% by mass with respect to the total amount of pellets. After sufficiently saturating the carbon dioxide gas, cooling to a temperature suitable for foaming, extruding from the die into a cylindrical shape, and a cylindrical mandrel extruded from the annular die of the extruder to cool the inner surface of the foam It passed between the foam cooling air rings that cool the outer surface of the foam, and a part of the diameter was cut and developed into a sheet to obtain a long foam original fabric.
This long foam original fabric is cut into a predetermined width (slit processing), and by using the continuous slicing device (slice line) shown in FIG. A foam layer A, a resin foam layer B, and a resin foam layer C were obtained. Further, 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: thickness 0.20 mm
Resin foam layer B: thickness 0.30 mm
Resin foam layer C: thickness 0.40 mm

(Example 1)
Double-sided pressure-sensitive adhesive tape (trade name “No. 5603”, manufactured by Nitto Denko Corporation, pressure-sensitive adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both surfaces of a PET substrate, tape thickness (thickness): 0.03 mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.23 mm.

(Example 2)
Double-sided pressure-sensitive adhesive tape (trade name “No. 5603”, manufactured by Nitto Denko Corporation, pressure-sensitive adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both sides of a PET substrate, tape thickness (thickness): 0.03 mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.33 mm.

(Example 3)
By passing the resin foam layer A 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, one side is melt-processed by heat, and one side is heat-melted. A resin foam layer having a thickness of 0.10 mm was obtained. The surface coverage of the heat-melted surface layer was 89.1%. Thereafter, a double-sided pressure-sensitive adhesive tape (trade name “No. 5603”, manufactured by Nitto Denko Corporation, a pressure-sensitive adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both sides of a PET base material, tape thickness (thickness) : 0.03 mm) was bonded together to obtain a resin foam composite. The total thickness of this resin foam composite was 0.13 mm.

Example 4
Double-sided pressure-sensitive adhesive tape (trade name “No. 5603”, manufactured by Nitto Denko Corporation, pressure-sensitive adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both surfaces of a PET substrate, tape thickness (thickness): 0.03 mm) was bonded. The total thickness of the obtained structure was 0.23 mm. With the PET release liner (thickness 0.075 mm) protecting the pressure-sensitive adhesive layer surface attached, 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. As a result, the surface of the structure to which the double-sided pressure-sensitive adhesive tape was not applied was melted with heat to obtain a resin foam composite. In this resin foam composite, the thickness of the resin foam layer whose one surface 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. The surface coverage of the heat-melted surface layer was 88.4%.

(Example 5)
By passing the resin foam layer A 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, one side is melt-processed by heat, and one side is heat-melted. A resin foam layer having a thickness of 0.10 mm was obtained. The surface coverage of the heat-melted surface layer in this resin foam layer was 89.1%. Thereafter, a double-sided pressure-sensitive adhesive tape (trade name “No. 5601”, manufactured by Nitto Denko Corporation, an acrylic pressure-sensitive adhesive layer on both sides of a PET base material is provided on the surface of the resin foam layer that has not been heat-melted. And a tape thickness (thickness): 0.01 mm) to obtain a resin foam composite. The total thickness of this resin foam composite was 0.11 mm.

(Example 6)
Double-sided pressure-sensitive adhesive tape (trade name “No. 5601”, manufactured by Nitto Denko Corporation, pressure-sensitive adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both surfaces of a PET substrate, tape thickness (thickness): 0.01 mm). The total thickness of the obtained structure was 0.21 mm. With the PET release liner (thickness 0.075 mm) protecting the pressure-sensitive adhesive layer surface attached, 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. Thus, the surface on which the double-sided pressure-sensitive adhesive tape was not attached was melted with heat to obtain a resin foam composite. In this resin foam composite, the thickness of the resin foam layer whose one surface 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. The surface coverage of the heat-melted surface layer was 94.1%.

(Example 7)
By passing the resin foam layer A 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, one side is melt-processed by heat, and one side is heat-melted. A resin foam layer having a thickness of 0.10 mm was obtained. The surface coverage of the heat-melted surface layer in this resin foam layer was 89.1%. Thereafter, a double-sided pressure-sensitive adhesive tape (trade name “No. 5600”, manufactured by Nitto Denko Corporation, an adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both surfaces of a PET base material on the surface of the resin foam layer that has not been heat-melted. And a tape thickness (thickness: 0.005 mm) were bonded together to obtain a resin foam composite. The total thickness of this resin foam composite was 0.105 mm.

(Comparative Example 1)
Double-sided pressure-sensitive adhesive tape (trade name “No. 5610”, manufactured by Nitto Denko Corporation, pressure-sensitive adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both surfaces of a PET substrate, tape thickness (thickness): 0.10 mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.30 mm.

(Comparative Example 2)
Double-sided pressure-sensitive adhesive tape (trade name “No. 5603”, manufactured by Nitto Denko Corporation, pressure-sensitive adhesive tape provided with an acrylic pressure-sensitive adhesive layer on both sides of a PET substrate, tape thickness (thickness): 0.03 mm) was bonded to obtain a resin foam composite. The total thickness of this resin foam composite was 0.43 mm.

(Comparative Example 3)
By passing the resin foam layer A 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, one side is melt-processed by heat, and one side is heat-melted. A resin foam layer having a thickness of 0.10 mm was obtained. The surface coverage of the heat-melted surface layer in this resin foam layer was 87.2%. Thereafter, a double-sided pressure-sensitive adhesive tape (trade name “No. 5608”, manufactured by Nitto Denko Corporation, an acrylic pressure-sensitive adhesive layer on both surfaces of a PET base material is provided on the surface of the resin foam layer that has not been heat-melted. And a tape thickness (thickness): 0.08 mm) to obtain a resin foam composite. The total thickness of this resin foam composite was 0.18 mm.

(Comparative Example 4)
On the PET surface side of urethane foam (trade name “PORON SR-S-32P”, thickness 0.20 mm, foam layer density 0.32 g / cm ³ , manufactured by Roger Sinoac Co., Ltd.) whose one side is supported by PET film, Double-sided adhesive tape (trade name “No. 5603”, manufactured by Nitto Denko Corporation, adhesive tape with acrylic adhesive layer provided on both sides of PET base material, tape thickness (thickness): 0.03 mm) are bonded together, and resin A foam composite was obtained. The total thickness of this resin foam composite was 0.23 mm.

(Comparative Example 5)
Double-sided adhesive tape (trade name “No. 5603”, Nitto) on polyolefin-based foam (trade name “Bora La WF03”, manufactured by Sekisui Chemical Co., Ltd., thickness 0.30 mm, density: 0.20 g / cm ³ , sheet shape) A resin foam composite was obtained by pasting together an adhesive tape made by Denko Co., Ltd., and an adhesive tape provided with an acrylic adhesive layer on both sides of the PET substrate, tape thickness (thickness): 0.03 mm. The total thickness of this resin foam composite was 0.33 mm.

[Evaluation]
(Apparent density)
The resin foam layer was punched with a punching blade mold having a width of 40 mm and a length of 40 mm to obtain a sheet-like measurement sample. And the apparent density (g / cm < ³ >) was calculated | required from the said sample for a measurement according to JISK6767.
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 measurement terminal diameter (φ) of 20 mm. The volume (cm ³ ) of the resin foam layer was calculated from these measured values. Next, the mass (g) of the measurement sample was measured with an upper pan balance having a minimum scale of 0.01 g or more. The apparent density (g / cm ³ ) was calculated from the measured values of the volume and mass.

(Average cell diameter)
A digital microscope (trade name “VHX-500” manufactured by Keyence Corporation) is used to capture an enlarged image of the foam bubble, and image analysis is performed using image analysis software (trade name “Win ROOF”, manufactured by Mitani Corporation). The average cell diameter (μm) was determined. Note that the number of bubbles in the captured enlarged image is about 100.

(Surface coverage)
The surface coverage of the surface of the resin foam layer that was melt-treated with heat was measured, and the value was defined as the surface coverage of the resin foam layer.
The surface coverage was obtained from the following formula (1).
Surface coverage (%) = [(surface area) − (area of pores existing on the surface)] / (surface area) × 100 (1)
The area of the surface and the area of the holes existing on the surface were determined from the image of the measurement surface obtained using a microscope (device name “VHX600”, manufactured by Keyence Corporation).
In observation with a microscope, side illumination was adopted as the illumination method, and the illuminance was 17000 lux. The magnification was 500 times.
A lens camera with built-in illumination (device name “0P72404”, manufactured by Keyence Corporation) was used as the illumination and camera, and a zoom lens (trade name “VH-Z100”, manufactured by Keyence Corporation) was used as the lens.
The illuminance was adjusted using an illuminometer (trade name “VHX600”, manufactured by Custom Inc.).

(Compression load at 50% compression)
Based on JIS K 6767, the stress (N) is measured when 10 seconds have elapsed after compression of 50% of the initial foam thickness in the thickness direction of the resin foam layer, and the stress is measured in unit area (cm ² ). Converted to hit, it was defined as compression stress (N / cm ² ) at 50% compression. The results are shown in Tables 1 and 2.

(Compression load when 0.10 mm is inserted)
For the resin foam composites of Examples and Comparative Examples, the stress (N) was measured when 10 seconds passed after compression so that the thickness was 0.10 mm in the thickness direction based on JIS K 6767. Was converted per unit area (cm ² ) to obtain a compressive load (N / cm ² ) upon insertion of 0.10 mm. 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 if it is used for a narrow gap of 0.1 mm. The results are shown in Tables 1 and 2.

(Compression load when 0.05 mm inserted)
For the resin foam composites of Examples and Comparative Examples, the stress (N) was measured when 10 seconds passed after compression so that the thickness was 0.05 mm in the thickness direction based on JIS K 6767. Was converted per unit area (cm ² ) to obtain a compressive load (N / cm ² ) when 0.05 mm was inserted. If the compressive load at the time of 0.05 mm insertion 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.

(Adhesive force)
After the resin foam composite (width: 20 mm × length: 120 mm) is stored for 24 hours or more in an atmosphere of temperature: 23 ± 2 ° C. and humidity: 50 ± 5% RH (pretreatment conditions are in JIS Z 0237) In the form where the adherend (SUS) and the pressure-sensitive adhesive layer surface of the resin foam composite are in contact with each other, they are pressure-bonded under conditions of 2 kg roller and 1 reciprocation, and left for 30 minutes to obtain a measurement sample. Thereafter, one end of the resin foam composite is pulled with an all-purpose tensile tester (device name “TCN-1kNB” manufactured by Minebea Co., Ltd.) in an atmosphere of temperature: 23 ± 2 ° C. and humidity: 50 ± 5% RH. The adhesive strength when peeled at a speed of 300 mm / min and a peel angle of 90 ° was measured. If the adhesive force is 2 N / 20 mm or more, it is determined that the adhesive force does not hinder the alignment during the bonding operation. The results are shown in Tables 1 and 2.

In Examples, a resin foam layer having an apparent density of 0.03 to 0.30 g / cm ³ and a compressive stress of 50 N / cm ² or less at 50% compression is used, and a thickness is 0.005 mm to 0.00. In combination with the 06 mm pressure-sensitive adhesive layer, a resin foam composite having a total thickness of 0.35 mm or less is used, and in a corresponding evaluation when inserted into a 0.1 mm gap, the compression load is 3.5 N / cm. Good results with ² or less could be obtained. Furthermore, it was possible to obtain a resin foam composite that can be applied to a gap of 0.05 mm. Further, the adhesive force at that time is also determined to have an adhesive force that does not hinder the alignment during the bonding operation.

On the other hand, in Comparative Example 1 and Comparative Example 3, the thickness of the pressure-sensitive adhesive layer is not less than a specific range, and in Comparative Example 2, the total thickness of the resin foam composite is not less than the specific range. It can be seen that the compressive load value when 1 mm is inserted is high. Moreover, in the comparative example 4 which is a foam whose apparent density is a specific value or more, it is understood that the cushioning property is poor and the compression load value when 0.1 mm is inserted becomes high. Furthermore, it can be seen that also in Comparative Example 5 using a foam having a compressive stress at the time of 50% compression of a specific value or more, the cushioning property is poor, and the compressive load value when 0.1 mm is inserted becomes high.

The resin foam composite of the present invention is used for applications such as a dustproof material, a seal material, a soundproof material, and a buffer material used when attaching various members or parts to a predetermined site.

1 Continuous slice device (slice line)
11 Feeding roll 12 Pinch roll 13 Blade (slicing blade)
DESCRIPTION OF SYMBOLS 14 Guide roll 15 Winding roll 16 Resin foam 2 Continuous processing apparatus which has a heating roll 21 Feeding roll 22 Guide roll 23 Heating roll (thermal dielectric roll)
24 Cooling roll 25 Winding roll 26 Resin foam a Flow direction

Claims

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 or less,
The pressure-sensitive adhesive layer has a thickness of 0.0005 mm to 0.06 mm;
A resin foam composite in which the total thickness of the resin foam composite is 0.35 mm or less.
2. The resin foam composite according to claim 1, wherein the ratio of the thickness of the resin foam layer to the thickness of the pressure-sensitive adhesive layer (the thickness of the resin foam layer / the thickness of the pressure-sensitive adhesive layer) is 2.1 or more. .
The resin foam composite according to claim 1 or 2, wherein the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer.
The resin foam composite according to any one of claims 1 to 3, wherein the resin constituting the resin foam layer is a thermoplastic resin.
The resin foam composite according to any one of claims 1 to 4, wherein the thermoplastic resin is a polyolefin resin.
6. The resin foam composite according to any one of claims 1 to 5, which has a surface layer formed by heat melting treatment on at least one surface of the resin foam layer.
The resin foam composite according to any one of claims 1 to 6, wherein the resin foam layer is formed through a step of depressurizing after impregnating a resin with a high-pressure gas.
The resin foam composite according to claim 7, wherein the gas is an inert gas.
The resin foam composite according to claim 8, wherein the inert gas is carbon dioxide.
The resin foam composite according to any one of claims 7 to 9, wherein the high-pressure gas is in a supercritical state.
The resin foam composite according to any one of claims 1 to 10, wherein the resin foam layer has a closed cell structure or a semi-continuous semi-closed cell structure.