TW201938360A - Layered product and method for manufacturing same - Google Patents

Abstract

Provide are: a layered product that is obtained by stacking a film on at least one surface of a sheet-shaped foam, and that satisfies requirements (A) to (E); and a method for manufacturing the layered product. (A) The foam has a thickness of 0.05-1.5 mm. (B) The film has a thickness of 25-250 [mu]m. (C) The film has a surface resistivity of at least 1 * 10<SP>11</SP> [Omega]. (D) The foam and the film are directly joined together without an adhesive therebetween. (E) The peel strength between the foam and the film is 10-100 mN/25 mm. With the present invention, a layered product can be provided that enables various kinds of processing to be preferably performed on a thin foam thereof without causing deformation of the foam, a film can be properly detached from the layered product, and the foam can be readily used alone. Furthermore, since the layered product is formed without an adhesive, it is possible to eliminate the possibility of any adhesive remaining on the foam after detachment of the film.

Description

Laminated body and manufacturing method thereof

The present invention relates to a laminated body obtained by laminating a sheet-like foam and a film, and a method for manufacturing the same. In particular, the present invention relates to a laminated body that is not deformed by a laminated film even if the foam is thin. The laminated body can be processed as desired, and the laminated body can be easily and appropriately peeled off from the laminated body so that the foam can be used in a single form, and a method for producing the laminated body.

Foams (for example, polyolefin-based resin foams) are used for various applications because they have uniform and fine closed cells and have excellent cushioning or processability characteristics. Such a foam can be easily formed into a thin film by stretching, slice processing, or the like. Even in the state where the thin film is formed, it has good cushioning properties or shock absorption properties. Used as a cushioning material for electronic and electrical equipment such as mobile phones. The foam may be used in the form of a single foam, and may be used in a state where an adhesive layer is provided on one surface or both surfaces of the foam. Regardless of the presence or absence of an adhesive layer, this foam is used as a buffer after being subjected to various processes such as slit processing to adjust the width in accordance with the shape of the electronic and electrical equipment or press processing to match the shape. Materials and the like are assembled into a housing of an electronic or electrical device and used.

The foams used as described above are usually very thin, having a thickness of about 0.05 mm to 1.5 mm, and further about 0.05 mm to 0.5 mm. In addition, since the density is lowered to provide cushioning properties, the strength is low, so When various types of processing as described above are to be performed, problems such as deformation or wrinkles may occur due to being stretched due to tension during transportation. In addition, for the purpose of improving shock absorption, etc., when the resin itself has an adhesive foam such as ultra-low density polyethylene, ethylene-vinyl acetate copolymer, or the like, there is also the following problem: foaming When the body is rolled into a roll for long-term storage, the foams are in close contact with each other and a phenomenon called blocking occurs. When the foam is peeled and rolled out for use, the foam needs to be removed. Too much tension. As described above, when processing a foam having a thin thickness, particularly a low density, various problems such as deformation, wrinkles, and adhesion may occur.

In order to solve these problems, a method of winding a foam together with a release paper (including a concept of a release film) and the like are considered (for example, Patent Document 1). However, in the case of using the release paper alone, especially in the case of a thin foam, there is a possibility that problems such as air entering between the foam and the release paper, deformation of the foam, and the like may occur. In addition, there are also methods such as rolling a film with an adhesive onto the foam after laminating it, but even if the film is to be peeled off and used only to obtain the foam layer, it still locally adheres to the foam layer side and is used. There exists a possibility that a binder may remain, and it is difficult to obtain a desired foam utilization form.
[Prior Art Literature]
[Patent Literature]

[Patent Document 1] WO2016 / 093133A1

[Problems to be Solved by the Invention]

Therefore, an object of the present invention is to provide a foam that is not deformed during various processing of a thin foam and can be processed as desired, and that the film can be easily and appropriately peeled from the laminated body, thereby enabling A laminated body in which a foam is used in a single form without causing problems, and a method for producing the laminated body.
[Means for solving problems]

The present inventors conducted intensive studies, and as a result, found that the problems described above can be solved by the laminated body described below and a method for manufacturing the same.
That is, the laminated body of this invention has the following structures.
(1) A laminated body, which is a laminated body in which a thin film is laminated on at least a single surface of a sheet-like foam, and the laminated body is characterized in that the following necessary conditions (A) to (E) are satisfied:
(A) The thickness of the foam is 0.05 mm to 1.5 mm;
(B) The thickness of the film is 25 μm to 250 μm;
(C) The surface resistivity of the film is above 1 × 10 ¹¹ Ω;
(D) The foam and the film are directly bonded without an adhesive;
(E) The peel strength of the foam and the film is 10 mN / 25 mm to 100 mN / 25 mm.
(2) The laminated body according to (1), wherein the thickness of the foam is 0.05 mm to 0.5 mm.
(3) The laminated body according to (1) or (2), wherein the peel strength of the foam and the film is in a range of 25 mN / 25 mm to 100 mN / 25 mm.
(4) The multilayer body according to (1) or (2), wherein the potential of the multilayer body is in a range of -30 kV to +30 kV.
(5) The multilayer body according to (4), wherein the potential of the multilayer body is in a range of -15 kV to +15 kV.
(6) The laminated body according to (1) or (2), wherein either of the foam and the film is mainly composed of an olefin-based resin.
(7) The laminated body according to (1) or (2), wherein the apparent density of the foam is in a range of 100 kg / m ³ to 500 kg / m ³ .
(8) The laminated body according to (1) or (2), wherein a surface of the film on the side which is in close contact with the foam is charged.
(9) The laminated body according to (1) or (2), wherein the foam of the release film is used to fix parts constituting the electronic and electrical equipment to the equipment main body.

The manufacturing method of the laminated body of this invention has the following structures.
(10) A method for producing a laminated body, which is a method for producing a laminated body in which a sheet-like foam is closely adhered to a film. The method for producing the laminated body is characterized in that: Either a charging step of applying a charge to charge the battery, or an adhesion step of closely contacting the foam with the film.
(11) The method for manufacturing a laminated body according to (10), which, after the adhesion step, has a charge having an opposite polarity to the charge on the outer surface of the foam or the film, which is opposite to the charge on the close contact surface of the foam and the film, The step of increasing the adhesion force to increase the adhesion force on the adhesion surface.
(12) The method for producing a laminated body according to (10) or (11), wherein in the charging step, the surface of the film on the side which is in close contact with the foam is charged.
(13) The method for manufacturing a laminated body according to (10) or (11), wherein the adhesion step includes a step of pressure-bonding the foam and the film by a nip roller.
(14) The method for manufacturing a laminated body according to (10) or (11), which uses the following materials (A) and (B):
(A) Foam with a thickness of 0.05 mm to 1.5 mm;
(B) A thin film having a thickness of 25 μm to 250 μm and a surface resistivity of 1 × 10 ¹¹ Ω or more.
(15) The method for producing a laminated body according to (14), wherein the thickness of the foam is 0.05 mm to 0.5 mm.
[Effect of the invention]

According to the laminated body of this invention and its manufacturing method, the laminated body which can perform desired processing without deform | transformation of a foamed body at the time of various processing of a thin foamed body can be provided. Moreover, since the film can be appropriately peeled from the laminated body, the foam can be easily used in a single form. Furthermore, by forming a laminated body without using an adhesive, the possibility that an adhesive may remain on the foam after peeling a film can be eliminated.

Hereinafter, the present invention will be described in detail together with the embodiments.
The thickness of the sheet-like foam used in the present invention is 0.05 mm to 1.5 mm. When the thickness of the foam is less than 0.05 mm, impact absorption or cushioning properties become insufficient. On the other hand, if the thickness exceeds 1.5 mm, it is not preferable to reduce the thickness of the electronic and electrical equipment, especially when it is used to fix components constituting the electronic and electrical equipment to the equipment main body. A more preferable range is a thickness of 0.05 mm to 0.5 mm.

The foam used in the present invention is mainly composed of an olefin-based resin, particularly a polyolefin-based resin. The polyolefin-based resin is not particularly limited, and examples thereof include polyethylene-based resins represented by low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene (herein mentioned The definition of the density is as follows: ultra-low density: less than 0.910 g / cm ³ , low density: 0.910 g / cm ³ or more and 0.940 g / cm ³ or less, high density: more than 0.940 g / cm ³ and 0.965 g / cm ³ The following) or copolymers containing ethylene as the main component, or polypropylene resins such as homopolypropylene, ethylene-propylene random copolymers, and ethylene-propylene block copolymers, etc. Any mixture. Examples of the copolymer containing ethylene as the main component include ethylene and an α-olefin having 4 or more carbon atoms (for example, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, and the like), and ethylene-α-olefin copolymers, ethylene-vinyl acetate copolymers, and the like. As the polyolefin-based resin, polyethylene resins such as low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene, ethylene-α-olefin copolymers, and ethylene-vinyl acetate copolymers are more preferable. Further preferred are low-density polyethylene, linear low-density polyethylene, and ultra-low-density polyethylene. These polyolefin-based resins may be any one kind or a mixture of two or more kinds. The most preferable is a low density polyethylene, a linear low density polyethylene, a monomer of an ethylene-vinyl acetate copolymer, or a mixture thereof.

Furthermore, as long as it is in a range that does not significantly impair the characteristics of the foam, a thermoplastic resin other than a polyolefin-based resin may be added. In the case of thermoplastic resins other than the polyolefin-based resins mentioned herein, in the case of halogen-free resins, acrylic resins such as polystyrene, polymethyl methacrylate, or styrene-acrylic copolymer may be mentioned. , Styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, polyvinyl pyrrolidone, petroleum resin, cellulose, cellulose acetate, nitric acid Cellulose derivatives such as cellulose, methyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, low molecular weight polyethylene, high molecular weight polyethylene, polypropylene and other polyolefins, saturated alkyl polyester resins, polypairs Aromatic polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyarylate, polyamine resin, polyacetal resin, polycarbonate resin, polyester resin, polyphenylene sulfide Resins, polyetherketone resins, copolymers having vinyl polymerizable monomers and nitrogen-containing vinyl monomers, and the like. Further examples include polystyrene-based thermoplastic elastomers (SBC, TPS), polyolefin-based thermoplastic elastomers (TPO), vinyl chloride-based thermoplastic elastomers (TPVC), and polyurethane-based thermoplastic elastomers (TPU). ), Polyester based thermoplastic elastomers (TPEE, TPC), polyamide based thermoplastic elastomers (TPAE, TPA), polybutadiene based thermoplastic elastomers (RB), hydrogenated styrene butadiene rubber (HSBR), Styrene · ethylene butene · olefin crystalline block polymer (SEBC), olefin crystal · ethylene butene · olefin crystalline block polymer (CEBC), styrene · ethylene butene · styrene block polymer (SEBS) Block copolymers such as olefin block copolymers (OBC) or polyolefin-vinyl graft copolymers, polyolefin-amidamine graft copolymers, α-olefin copolymers, polyolefin-acrylic grafts Elastomers such as copolymers and graft copolymers such as polyolefin-cyclodextrin-based graft copolymers.

In the case of a halogen-containing resin, examples thereof include polyvinyl chloride, polyvinylidene chloride, polytrifluorochloroethylene, polyvinylidene fluoride resin, fluorocarbon resin, perfluorocarbon resin, and solvent solubility. Perfluorocarbon resin, etc. The thermoplastic resin other than these polyolefin-based resins may be one type, or may contain multiple types. In particular, for the purpose of imparting flexibility or impact absorption, a preferable aspect is to add an elastomer, and the type and amount are selected in accordance with desired physical properties.

To the foam used in the present invention, phenol-based, phosphorus-based, amine-based, sulfur-based antioxidants, metal inhibitors, mica, talc, etc. can be added within a range that does not impair the effects of the present invention. Fillers, flame retardants such as bromine and phosphorus, flame retardant additives such as antimony trioxide, antistatic agents, lubricants, pigments, and additives such as polytetrafluoroethylene.

The foam used in the present invention may be colored black. As a black colorant used when coloring to black, for example, carbon black (furnace black, groove black, acetylene black, thermal carbon black, lamp black, etc.), graphite, copper oxide, manganese dioxide, aniline black, and rhenium can be used. Black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, composite oxide system All known coloring agents, such as a black pigment and an anthraquinone organic black pigment. Among these, carbon black is preferred from the viewpoints of cost and availability.

Black colorants can be used alone or in combination of two or more. The amount of the black colorant used is not particularly limited, and an amount that is appropriately adjusted so as to provide desired optical characteristics to the double-sided adhesive sheet of the present invention can be used.

The apparent density of the foam used in the present invention is preferably 100 kg / m ³ to 500 kg / m ³ . When the apparent density is less than 100 kg / m ³ , the strength of the foam is reduced, wrinkles and the like are easily generated during processing, and impact absorption is reduced, which is not preferable. If it exceeds 500 kg / m ³ , it will become hard and the cushioning property will decrease, so it is not good. A more preferable range is 200 kg / m ³ to 400 kg / m ³ .

As the foam used in the present invention, any of a crosslinked foam (referred to as a crosslinked foam) and an uncrosslinked foam (a non-crosslinked foam) can be used. What is necessary is just to select an appropriate foam according to a use or a shape. However, in terms of the smoothness of the surface of the resin foam, improvement in heat resistance, and the ability to further reduce the thickness of the foam produced by stretching or calendering, a crosslinked foam is preferably used. The crosslinking degree of the crosslinked foam is preferably in the range of 5% to 50%.

The surface resistivity of the foam used in the present invention is not particularly limited, but is preferably 1 × 10 ¹⁰ Ω or more. When the surface resistivity is less than 1 × 10 ¹⁰ Ω, the adhesion to the film is reduced, and therefore, it is not good. It is more preferably 1 × 10 ¹² Ω or more. In order to adjust the surface resistivity, it is preferable to use a polyolefin-based resin as a main constituent, and to add an antistatic agent and the like as necessary. Examples of such an antistatic agent include monomeric antistatic agents such as N, N-bis (hydroxyethyl) alkylamine, alkylallylsulfonate, and alkylsulfonate; 1- Ionic liquids such as propyl-3-methylpyridinium ･ bistrifluoromethanesulfonate, 1-butyl-3-methylpyridinium ･ trifluoromethanesulfonate, polyethylene oxide, polypropylene oxide Quaternary ammonium salts such as polyethylene glycol, polyester ammonium amine, polyether ester ammonium amine, ethylene-methacrylic acid copolymer, polyethylene glycol methacrylate copolymer, etc., Japanese Patent Laid-Open No. 2001 A high-molecular-weight antistatic agent such as a copolymer of an olefin-based block and a hydrophilic block described in JP-278985.

The centerline surface roughness Ra of the foam used in the present invention is preferably 30 μm or less. When the surface roughness of the foam exceeds 30 μm, when a laminate of the foam and the film is formed, air easily enters the interface and the adhesiveness tends to decrease, which is not satisfactory. It is more preferably 25 μm or less.

As a method for producing a foam to be used in the present invention, a conventionally known method can be used. For example, using a thermally decomposable foaming agent, after molding the resin composition into a sheet shape, irradiating it with ionizing radiation to crosslink the resin, the sheet is heated to a temperature higher than the decomposition temperature of the foaming agent, and A method for producing an electron beam crosslinked foam obtained from a foam; forming the same thermally decomposable foaming agent and organic peroxide together with the resin composition into a sheet shape, and heating the same to make the resin side A method for producing a crosslinked foamed chemically crosslinked foamed body; injecting carbon dioxide gas or nitrogen gas or butane gas in a supercritical state from the middle of an extruder and extruding from a die to obtain a foamed body Production method of extruded foam and the like.

Furthermore, those obtained by thinning the foams produced by these methods can also be preferably used. The thinning is performed by slicing, cutting, and thinning the foam in the thickness direction. Uniaxial or biaxial stretching is performed while heating, and compression processing of a heated foam sandwiched by a roller or the like is performed alone or in combination.

The average cell diameter of the foam used in the present invention is not particularly limited, but when the average cell diameter is small, the surface becomes smooth, and the adhesiveness when the laminated body is made is improved, and from the viewpoint of flexibility, good. If it is to be too small, it is necessary to make the resin highly viscous, which will significantly reduce productivity. From such a viewpoint, the average cell diameter of the foam is preferably in the range of 20 μm to 400 μm, and more preferably in the range of 20 μm to 200 μm.

The average cell diameter of the foam is calculated as follows. A scanning electron microscope (SEM) (Hitachi High-technologies Co., Ltd., S-3000N) was used to observe the cross section of the foam sheet at a magnification of 50 times, and the obtained image and The measurement software determines the bubble diameter (diameter). In addition, the bubble diameter is measured in the length direction (MD) and width direction (TD) in the range of 1.5 mm × 1.5 mm of the captured image, and the average bubble diameter in each direction is calculated, and the average value is used as the average. Bubble diameter. In addition, the measurement was performed in 10 visual fields, and it was calculated | required as an arithmetic mean.

Next, the thin film used in the laminated body of this invention is demonstrated.
The thickness of the film used in the present invention is in the range of 25 μm to 250 μm. If it is less than 25 μm, wrinkles are easily generated when a cutting process for adjusting the laminated body to an optimal width is performed, and, for example, the laminated body is easily deformed during press processing, and workability is deteriorated. good. In the case of more than 250 μm, there is a lack of economic rationality. The film may be either a stretched film or a non-stretched film, but in order to prevent deformation of the laminate, a biaxially stretched film is most preferred.

The surface resistivity of the thin film used in the present invention needs to be 1 × 10 ¹¹ Ω or more, and preferably 1 × 10 ¹⁸ Ω or less. When the surface resistivity is less than 1 × 10 ¹¹ Ω, the potential disappears when it contacts the foamed volume layer, and it cannot be in close contact with the foam. The surface resistivity of the film can be adjusted by the amount of the antistatic agent added to the resin composition constituting the film. When an antistatic agent is added, a known one can be used.

The material of the film used in the present invention is not particularly limited, but in order to maintain the potential of the laminated body in an appropriate range, and from the viewpoint of economical rationality, it is preferably composed mainly of an olefin resin. Examples of the polyolefin-based resin include polyethylene resins represented by low-density polyethylene, high-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene (the definition of the density mentioned here is as follows) : Ultra-low density: less than 0.910 g / cm ³ , low density: 0.910 g / cm ³ or more and 0.940 g / cm ³ or less, high density: more than 0.940 g / cm ³ and 0.965 g / cm ³ or less) A copolymer based on a main component, or a polypropylene resin typified by a homopolypropylene, an ethylene-propylene random copolymer, an ethylene-propylene block copolymer, or the like, may also be any of these mixtures. Among these, from the viewpoint of making wrinkles less likely to occur when the laminated body is processed, a film mainly composed of polypropylene having high rigidity is preferable. Furthermore, even if it is a homopolymer including propylene, it may contain a copolymerization component formed from other unsaturated hydrocarbons, etc. within a range that does not impair the object of the present invention, or it may be blended with a polymer having propylene alone. . Examples of the monomer component constituting such a copolymerization component or blend include ethylene, propylene (in the case of a copolymerized blend), 1-butene, 1-pentene, and 3-methylpentene. -1, 3-methylbutene-1, 1-hexene, 4-methylpentene-1, 5-ethylhexene-1, 1-octene, 1-decene, 1-dodecene , Vinylcyclohexene, styrene, allylbenzene, cyclopentene, norbornene, 5-methyl-2-norbornene and the like. The copolymerization amount or the blending amount is preferably in terms of insulation breakdown resistance and rigidity in terms of a copolymerization amount of less than 1 mol% and a blending amount of less than 10% by mass.

Next, the laminated body of this invention is demonstrated.
The laminated body of the present invention needs to directly join the foamed body and the film without an adhesive. In the present invention, this direct bonding is achieved by applying an electric charge to either the foam or the film, and achieving the electrostatic adhesion using the electric charge. For this reason, after peeling a film from the laminated body of this invention, an adhesive does not exist on the film side surface of a foam.

The laminated body of the present invention can be assembled into an electronic / electrical equipment frame after performing various processes such as cutting or stamping. In particular, the foamed body in which the self-laminated body is peeled from the film can be used as a cushioning material having good cushioning or impact. Absorbent layers to assemble. As the assembly form of the foam, an adhesive layer is provided on the opposite side of the film of the foam, or a micro-adhesive layer is temporarily provided on the opposite side of the same film and aligned with the frame. Various forms, such as peeling a micro-adhesive layer, and providing an adhesive layer, or peeling a film on the film side surface of a foam, and providing an adhesive layer, are various. However, if there is an adhesive in advance on the surface of the foam, and in particular if an adhesive remains on the film-side surface of the foam after the film is peeled off, there is an adhesive that causes air to enter and then be applied. Interface, or the appearance is likely to drop, so it is not good.

In addition, the density of the foam is low, so the strength of the material is weak. When the adhesive layer provided or left on the foam is to be removed, the material of the foam may be damaged. Therefore, it is also difficult to remove an existing adhesive layer before a new adhesive layer is to be set.

On the other hand, since the laminated body of the present invention directly bonds the foam to the film without passing through an adhesive, there is no adhesive on the film-side surface of the foam after the film is peeled off, and the laminated body can be laminated. On the opposite side of the film of the foam supported by the film in the form, it is easy to provide an adhesive layer suitable for the application or part where the foam is used.

Conventionally, when an adhesive layer is provided on the surface of a foam, it is known to apply a liquid containing a solvent and an adhesive to a substrate such as a film or a release paper, and then to dry it using an oven or the like. A method of bonding to a foam and removing a film or release paper. Foam has low density and low strength, so it is easy to stretch under heating. Therefore, compared with coating a solution containing an adhesive on the foam side, apply adhesive to a film or release paper and dry it. The post-lamination method can improve the production speed, so it is preferably used. In this process, if a film is directly bonded to the non-adhesive side of the foam without using an adhesive in advance, deformation of the foam due to winding tension and the like can also be prevented.

As described above, in the present invention, by forming a laminated body in which a foam and a film are directly bonded without an adhesive, various processes are easily performed.

In the laminated body of the present invention, the peel strength of the foam and the film is in a range of 10 mN / 25 mm to 100 mN / 25 mm. If the peel strength of the foam and the film is less than 10 mN / 25mm, the foam and the film will peel during various processing of the laminated body, so it is not good. If it exceeds 100 mN / 25mm, peeling will occur. Poor deformation of the foam during the film is not preferred. More preferably, it is in the range of 25 mN / 25mm to 100 mN / 25mm. The peel strength of the foam and the film can be controlled by rationalizing conditions such as surface resistivity, surface roughness, and discharge amount of the foam or the film.

As mentioned above, the surface resistivity of the foam used in the present invention is preferably 1 × 10.¹⁰ Above Ω, the surface resistivity of the film used in the present invention is 1 × 10^{1 1} Ω or more, but if both materials have a low surface resistivity, there is a possibility that the adhesion strength between the foam and the film in the laminate may deviate from the range. Therefore, as a preferred combination, the surface resistivity is 1 × 10.¹⁶ Ω ～ 1 × 10¹⁸ Ω foam and surface resistivity 1 × 10¹¹ Ω ～ 1 × 10¹⁴ Laminated body of Ω thin film, surface resistivity is 1 × 10¹⁰ Ω ～ 1 × 10¹⁵ Ω foam and surface resistivity 1 × 10¹⁶ Ω ～ 1 × 10¹⁸ The laminated body of the Ω film is preferable because it can obtain a moderate adhesive strength that can achieve the range of the peel strength.

The potential of the multilayer body of the present invention is preferably in the range of -30 kV to +30 kV. If the absolute value of the potential exceeds ± 30 kV, in addition to the potential being too high, dust in the surrounding environment is likely to adhere, and self-discharge is liable to occur, which is not satisfactory. The range is more preferably -15 kV to +15 kV, and even more preferably -10 kV to +10 kV.

The laminated body of the present invention is preferably charged on the surface of the film that is in close contact with the foam. In order to make the film and the foam adhere to each other by charging, it is preferable to perform charging treatment on either or both of the film and the foam. However, when the foam is to be charged and processed at a high voltage, Since defects such as pin holes are liable to occur, it is preferred that the surface of the film that is in close contact with the foam is charged. Furthermore, any one of the surface of the film that is in close contact with the foam and the surface that is not in contact with the foam may be subjected to a charge treatment (in the case where the surface that is not in contact with the charge is subjected to a charge treatment, as a result, it is in contact with the foam Surface of the film), but in order to improve the adhesion strength, it is preferable to charge the surface of the film on the side that is in close contact with the foam.

In the laminated body, which side is charged can be confirmed by a toner method used in a spray copier called a dust figure method (Electrostatic Handbook, issued in 1981, edited by the Electrostatic Society, p .373). The powder image method is a method in which charged colored fine particles are floated near a charged body, and are attached and developed by electrostatic force. As a developing material used in the powder image method, a powder toner generally used in a color copying machine is suitable. The average particle diameter is preferably several μm to several tens μm. In addition, as the working environment, the adhesion of the powder varies depending on the surrounding humidity, so if the evaluation is performed in a fixed environment such as a humidity of 40% to 60%, the reproducibility is good.

For example, the following evaluation conditions can be applied.
Positively charged toner:
Color: Red Particle size: Weight average particle size: 14.8 μm (below 6 μm: 0.2% by weight, above 25 μm: 1.8% by weight)
Specific charge: -1.2 μC / g
Negatively charged toner:
Color: Blue Particle size: Weight average particle size: 12.5 μm (below 6 μm: 0.8% by weight, above 20 μm: 1.6% by weight)
Specific charge: -23.1 μC / g

The average particle diameter of the toner shown here is a value measured by using MULTISIZERII manufactured by COULTER and using an aperture tube having a diameter of 100 μm. The specific charge is a value measured by a blow off method charge amount measuring device (TB-500 model manufactured by Toshiba Chemical Co., Ltd.). Specifically, it was calculated | required by mixing the measured toner and the iron powder carrier (TSV-200R of powder-tech) at a weight ratio of 1:19, respectively, and using a ball mill 0.2 g of the powder sample after being stirred for 5 minutes was placed in a measurement cell of the charged amount measuring device, and was set at a blow pressure of 0.5 kg / cm ² and a blow time of 60 seconds. The mesh sieve was measured using a 400-mesh stainless steel sieve, and the value measured was divided by the weight of the toner (0.2 g × 1/20 = 0.01 g).

Next, referring to FIG. 1 which is one of the preferred aspects, a method for manufacturing the laminated body of the present invention using the foamed body and film will be described.

The manufacturing method of the laminated body 3 of this invention needs to have the charging step of applying a charge to either the sheet-like foam 2 or the film 1 sequentially, and the adhesion | attachment step of closely contacting a foam and a film. The charging step and the adhesion step may be performed by being connected to the step of manufacturing a foam, or may be performed after winding the foam.

The charging method of the charging device 4 that charges any one of the foam 2 or the film 1 and charges the charging device 4 is not particularly limited, and examples thereof include (1) on one side of the foam 2 or the film 1 A grounded flat electrode is overlapped, and needle electrodes or wire electrodes electrically connected to a DC high-voltage power supply are arranged at predetermined intervals on the other surface side of the foam 2 or the film 1. A method of generating a corona discharge by concentrating an electric field near the front end or the surface of a wire electrode to ionize the air to charge it; (2) using a pair of flat electrodes to sandwich the foam 2 or the thin film 1 and holding one of the flat plates A method for grounding an electrode, and connecting another flat electrode to a high-voltage DC power supply, and applying a DC or pulse-like high voltage to the foam 2 or the film 1 to charge them; (3) ionizing properties such as electron beams and X-rays As a method that can easily inject a charge, such as a method in which radiation or ultraviolet rays are irradiated to the foam 2 or the film 1 and ionize the nearby air to charge it, the method is preferably (1) a method using a corona discharge treatment. .

In the corona discharge treatment, the foam 2 or the film 1 can be charged by applying a voltage of 0 kV to ± 30 kV at a discharge distance of about 5 mm to 30 mm. In the case where the foam is charged, if the applied voltage is excessively increased, holes may appear when the discharge is concentrated, so it is preferably set to a range of 0 kV to ± 20 kV.

Further, the surface to be subjected to the corona discharge treatment may be any surface, and there is no limitation, but in order to improve the adhesion, it is more preferable to electrify the surface of the foam 2 or the film 1 that is in close contact with another material. Further, in order to uniformly adhere to the end of the product, it is necessary to widen the width of the electrode with respect to the width of the processing target of the film 1 or the foam 2.

The discharge amount at the time of charging treatment by corona discharge is preferably in the range of 0.5 J / m ² to 100 J / m ² . If the discharge amount is less than 0.5 J / m ² , the adhesion between the foam 2 and the film 1 is reduced, so it is not good. If it exceeds 100 J / m ² , pinholes may be generated in the film 1 or the foam 2. Possibility of waiting for a hole defect is therefore not good. More preferably, it is in the range of 1.0 J / m ² to 100 J / m ² .

The discharge amount is a value calculated by the following expression. Among them, the width of the electrode for discharging is wider than the width of the film 1 or the foam 2.

Discharge (J / m ² ) = Electricity (W) / {Linear speed (m / s) × Width of film or foam (m)}

As the step of bringing the foam 2 into close contact with the film 1, it can be achieved by bringing another material into contact with the foam 2 or the film 1 which has been subjected to a charging treatment to make it electrostatically tight. It is preferable to press the nip roll 6a, nip roll 6b, plate, or the like to the close contact surface as shown in FIG. In particular, from the viewpoint of continuous productivity, it is preferable to use the nip rollers 6a and 6b to make them in close contact. The material of the nip rolls 6a and 6b is not particularly limited, and conventionally known nip rolls made of metal-metal, nip rolls made of rubber-metal, and the like can be used.

In the present invention, it is particularly preferred that after the foam 2 is in close contact with the film 1, the foam 2 or the film 1 has an opposite polarity to that on the outer surface of the foam 2 and the film 1 on the close contact surface. Electric charge increases the contact force. For example, a positive charge is applied to the surface of the film 1 on the side in close contact with the foam body 2 by the charging device 4 as shown in FIG. 1 to perform a corona discharge treatment, and the foam body 2 is laminated to form a multilayer body 3. By using the static elimination device 5 to irradiate the outer surface of the foam 2 with negative charges, the charges are neutralized, the potential for the laminated body 3 can be reduced, and the adhesion between the foam 2 and the film 1 can be improved. In addition, it is also one of the preferable aspects to supply charges of opposite polarities in a state where positive charges and negative charges are mixed. The device for imparting charges of opposite polarity in this manner is not particularly limited, and examples thereof include a high-voltage application type static elimination device, a self-discharge type static elimination device, and a device that irradiates ionizing radiation such as soft X-rays or alpha rays. It is a high-voltage application type static elimination device using corona discharge. From the viewpoint of efficiently charging the foam 2 or the film 1, it is preferable to have the opposite roller 8 on the side opposite to the charging device 4 while sandwiching the foam 2 or the film 1. By providing the counter roller 8, an electric field can be formed between the counter roller 8 and the discharge electrode of the charging device 4, and the ions generated by the corona discharge can be efficiently sent to the foam 2 or film 1 on the roller, thereby Can improve the efficiency of charging process. The material of such an opposing roller 8 is not particularly limited, and any one of a metal roller and a rubber roller can be used. Among these, in the case of a rubber roller, if the roller is charged, the processing efficiency will be lowered. Therefore, a conductive rubber is preferred.

In addition, in order to manufacture the laminated body of the present invention, it is preferable to include a winder for winding the foam 2 and the film 1 at a constant tension and speed, and to apply appropriate tension to the foam 2 and the film 1 A guide roller 7 for preventing bending and the like is used to cut the laminated body 3 to a cutter having a target width, such as a cutter or a laser knife, and a winder for winding the laminated body.
[Example]

Hereinafter, the present invention will be described in detail using examples. The measurement methods and evaluation methods are shown below.

(1) Thickness of the foam The thickness of the foam is measured in accordance with ISO 1923 (1981) "Method for measuring foamed plastics and rubber-wire size". Specifically, a dial gauge with a circular measuring element having an area of 10 cm ^{2 was} used. After the foam cut into a fixed size was allowed to stand still on a flat table, The fixed pressure of g was in contact with the surface of the foam, and measurement was performed.

(2) Apparent density of the foam The apparent density of the foam is a value measured and calculated in accordance with JIS K6767 (1999) "Foam Plastics-Polyethylene-Test Method". The thickness of the foam cut into an area of 10 cm ² was measured, and the mass of the test piece was measured. The value obtained by the following formula was used as the apparent density, and the unit was set to kg / m ³ .

Apparent density (kg / m ³ ) = {mass of test piece (kg) / area of test piece 0.01 (m ² ) / thickness of test piece (m)}

(3) Degree of Crosslinking of Foam The measurement of the degree of crosslinking of the foam is performed as follows. The foam was cut into approximately 0.5 mm squares, and approximately 100 mg was weighed with an accuracy of 0.1 mg. After immersing in 200 ml of tetrahydronaphthalene at a temperature of 140 ° C for 3 hours, natural filtration was performed with a 100-mesh stainless steel metal mesh, and insoluble components on the metal mesh were dried in a hot air oven at 120 ° C for 1 hour. Then, it was cooled in a desiccator to which silica gel was added for 30 minutes, and the mass of the insoluble component was accurately weighed. The gel fraction of the foam was calculated as a percentage based on the following formula.

Degree of cross-linking (%) = {mass of insoluble component (mg) / mass of foam measured (mg)) × 100

(4) Surface roughness of the foam The surface roughness of the foam is measured with a surface roughness measuring device (model: SE-2300, manufactured by Kosaka Research Co., Ltd.), and the average roughness of the center line is determined. Degrees Ra. Here, the measurement part is a surface where the foam is laminated with the film. The measurement direction is the measurement in both the longitudinal direction and the direction perpendicular to the foam sheet in the plane of the foam sheet, and the number of measurements is one each. The highest value among these measured values is defined as the surface roughness of the foam.

(5) Thickness of the film The thickness of the film is a digital micrometer μ mate M-30 (Digital Micrometer μ mate M-30) manufactured by Sony Precision Technology Co., Ltd. The measurement was performed, and the average value was made into the film thickness.

(6) Surface resistivity of the foam and the film The surface resistivity was measured using R8340 manufactured by Advantest. The foam was cut into 50 mm × 50 mm, and left to stand for 24 hours under a temperature of 20 ° C. and a humidity of 50% RH. The surface resistivity after applying a voltage of 100 V for 1 minute was used. The average value was measured twice.

(7) Peel strength of the laminated body Regarding the peel strength of the laminated body, the produced laminated body was cut such that the length of the product in the longitudinal direction (winding direction in FIG. 1) became 150 mm and the width became 25 mm. Cut into test pieces. One end of this test piece was clamped together with the laminated body and fixed, and only the film of the laminated body was fixed at the other clamp entrance. TENSILON UCT-500 manufactured by ORIENTEC CORPORATION was used. The film was stretched at a speed of 200 mm / min, a peeling angle of 180 °, and a peeling distance of 80 mm, and a peeling test was performed. The obtained peeling strength is the maximum peeling strength value within a peeling distance of 80 mm, and the average value obtained from the values measured twice was taken as the peeling strength.

(8) Potential of the multilayer body The potential of the multilayer body was measured using a digital electrostatic potential measuring device KSD-1000 manufactured by Kasuga Electric Corporation. The film measurement and foam measurement of the self-laminated body were measured by approaching a potentiometer, and the average value was used as the potential of the laminated body.

(9) Evaluation of laminated body characteristics (cutting processability)
The produced laminated body was cut and evaluated for the presence or absence of wrinkles. A cutting machine connected to a mechanical motor and capable of unwinding and rewinding at an arbitrary speed is provided with a laser knife every 140 mm, and is cut at a processing speed of 40 m / min, and products with a width of 140 mm are simultaneously extracted. 6 pieces. A case where wrinkles were not found in even one of the six extracted products was regarded as acceptable (0), and a case where wrinkles existed even in one case was regarded as unacceptable (×).

Tables 1 and 2 show the foams and films used.
[Reference Example 1]
For 100 parts by weight of a linear low-density polyethylene resin with a density of 925 kg / m ³ , uniformly mix 2 kg of thermal decomposition type blowing agent Azodicarbonamide and 0.2 g of phenolic antioxidant Yilu Irganox 1010 was supplied to an extruder, extruded while being melt-kneaded at a resin temperature of 170 ° C, and formed into a long sheet shape. Next, the sheet was irradiated with an electron beam to crosslink the resin, and then continuously charged into a molten salt bath set at 235 ° C to produce a crosslinked foam A. The obtained foam had a thickness of 0.4 mm and a density of 250 kg / m ³ .

[Reference Example 2]
The foam produced in Reference Example 1 was stretched 200% in the lengthwise direction by four rollers set at 80 ° C, and then put into a tenter set at 120 ° C, while holding it with clamps Stretching 200% at both ends, a foam B having a thickness of 0.1 mm and a density of 300 kg / m ³ was produced.

[Reference Example 3]
In Reference Example 1, a foam having a thickness of 2 mm and a density of 430 kg / m ³ was produced by setting the amount of the thermally decomposable foaming agent to 4.5 kg. The surface layer of the produced foam was cut by 0.4 mm with a slicing machine, and then stretched in a lengthwise direction in a heating furnace set at a temperature of 110 ° C to produce a foam having a thickness of 0.5 mm and a density of 475 kg / m ³ Body C.

[Reference Example 4]
In Reference Example 1, a foamed body D was produced in the same manner except that 100 parts by weight of a polyethylene resin was added with 10 parts by weight of sodium dodecylbenzenesulfonate.

[Reference Example 5]
In Reference Example 1, a foamed body E was produced in the same manner except that 15 parts by weight of Ketjen Black was added to 100 parts by weight of the polyethylene-based resin.

[Reference Example 6]
Low-density polyethylene with a density of 918 kg / m ³ is fed from the hopper of the extruder, and supercritical carbon dioxide gas is injected in the middle of the first layer of the tandem extruder in which two uniaxial extruders are arranged. The second-layer extruder was used for cooling while extruding through a circular die, followed by molding with a mandrel, and then cutting to produce a non-crosslinked foam F.

[Reference Example 7]
For 100 parts by weight of an ethylene-vinyl acetate copolymer having a content of 14% of vinyl acetate, 2.7 kg of a thermal decomposition-type blowing agent azodimethylamine and 0.2 g of a phenolic antioxidant Irganox 1010, supplied to an extruder, extruded while melting and kneading at a resin temperature of 150 ° C, and formed into a long sheet shape having a thickness of 0.9 mm. Next, the sheet was irradiated with an electron beam to crosslink the resin, and then continuously charged into a molten salt bath set at 235 ° C to produce a crosslinked foam G. The obtained foam had a thickness of 1.5 mm and a density of 140 kg / m ³ .

The films shown in Table 2 were purchased and used as commercially available biaxially stretched polypropylene films.
Film a: P002 (40 μm thickness) manufactured by Toyobo Co., Ltd.
Film b: P2161 (thickness: 40 μm) manufactured by Toyobo Co., Ltd.
Film c: P2161 (thickness 30 μm) manufactured by Toyobo Co., Ltd.
Film d: PAS-P1M (thickness: 40 μm) manufactured by Futamura Chemical Co., Ltd.
Film e: PAS-P2 (thickness: 30 μm) manufactured by Futamura Chemical Co., Ltd.
Film f: P2102 (thickness 20 μm) manufactured by Toyobo Co., Ltd.

[Table 1]

[Table 2]

[Example 1]
As shown in Figure 1, the foam A with a product width of 1 m and the film b with a product width of 1 m were respectively installed on a winder, while being rolled out at a linear speed of 20 m / min. The charging device PST-2005N manufactured by the company set the distance between the electrode and the film surface at 15 mm at a voltage of -15 kV, and charged the side of the film that was in contact with the foam. Then, it was introduced into a nip roll and clamped under a pressure of 0.3 MPa, thereby laminating a foam and a film to form a laminate. Then, using a static eliminator (power supply: Power Unit 150, electrode ss-50) manufactured by SIMCO JAPAN Co., Ltd., the surface of the foam was neutralized at 4 kV, and the winding tension was set to 100. mN, convolution layer.

The potential of the produced laminated body was +3.1 kV, and the peel strength of the foam and the film was 40 mN / 25. Then, the laminated body was subjected to a cutting process, and as a result, a product having a good appearance without wrinkles and air intrusion caused by the deformation of the foam was obtained. The results are shown in Table 3.

[Example 2 to Example 14, Comparative Example 1, Comparative Example 2]
In Examples 2 to 14 and Comparative Examples 1 and 2, the laminated body was produced in the same manner as in Example 1 under the conditions shown in Table 3, and the obtained laminated body's potential, Measurement of adhesion strength and evaluation by cutting.

As shown in Table 3, in Examples 1 to 14 that satisfy the conditions prescribed by the present invention, good results were obtained, especially good cutting workability, but comparisons that did not satisfy the conditions prescribed by the present invention Good results were not obtained in Example 1 and Comparative Example 2.

[table 3]



[Industrial availability]

The laminated body of the present invention can be applied to applications in which a thin foam is particularly required, and is particularly preferably used when a cushioning material or an impact absorbing material is provided for electronic and electrical equipment such as a mobile phone.

1‧‧‧ film

2‧‧‧ foam

3‧‧‧ laminated body

4‧‧‧ charged device

5‧‧‧ static elimination device

6a, 6b ‧‧‧ pinch roller

7‧‧‧Guide roller

8‧‧‧ Opposite roller

FIG. 1 is a schematic configuration diagram showing a method for manufacturing a laminated body according to an embodiment of the present invention.

Claims (15)

A laminated body having a thin film laminated on at least a single surface of a sheet-like foam. The laminated body is characterized by satisfying the following requirements (A) to (E): (A) the foam The thickness of the film is 0.05 mm to 1.5 mm; (B) the thickness of the film is 25 μm to 250 μm; (C) the surface resistivity of the film is 1 × 10 ¹¹ Ω or more; (D) the foam It is directly bonded to the film without an adhesive; and (E) The peel strength of the foam and the film is 10 mN / 25 mm to 100 mN / 25 mm. The laminated body according to item 1 of the scope of patent application, wherein the thickness of the foam is 0.05 mm to 0.5 mm. The laminated body according to item 1 or item 2 of the scope of patent application, wherein the peel strength of the foam and the film is in a range of 25 mN / 25mm to 100 mN / 25mm. The laminated body according to item 1 or item 2 of the patent application scope, wherein the potential of the laminated body is in a range of -30 kV to +30 kV. The laminated body according to item 4 of the scope of patent application, wherein the potential of the laminated body is in a range of -15 kV to +15 kV. The laminated body according to item 1 or 2 of the scope of patent application, wherein either of the foamed body and the film is mainly composed of an olefin-based resin. The laminated body according to item 1 or item 2 of the scope of patent application, wherein the apparent density of the foam is in a range of 100 kg / m ³ to 500 kg / m ³ . The laminated body according to item 1 or item 2 of the scope of patent application, wherein the surface of the film that is in close contact with the foam is electrically charged. The laminated body according to claim 1 or claim 2, wherein the foamed body from which the film is peeled is used to fix parts constituting electronic and electrical equipment to a device body. A manufacturing method of a laminated body is a manufacturing method of a laminated body in which a sheet-like foam body and a film are closely adhered, and the manufacturing method of the laminated body is characterized in that: A charging step of applying a charge to either of the foam or the film to charge it; and In the adhesion step, the foam is closely adhered to the film. According to the method for manufacturing a laminated body according to item 10 of the scope of patent application, after the step of adhering, the method has a step of providing an outer surface of the foam or the film to the foam and the film. A step of increasing the adhesion force by increasing the adhesion force on the contact surface with a charge having an opposite polarity on the contact surface. The method for manufacturing a laminated body according to item 10 or item 11 of the scope of application for a patent, wherein in the charging step, a surface of the film on the side that is in close contact with the foam is charged. The method for manufacturing a laminated body according to item 10 or item 11 of the scope of patent application, wherein the adhesion step includes a step of pressure-bonding the foam and the film by a nip roller. The method for manufacturing a laminated body according to item 10 or 11 of the scope of patent application, which uses the following materials (A) and (B): (A) a foam having a thickness of 0.05 mm to 1.5 mm; and (B) A thin film having a thickness of 25 μm to 250 μm and a surface resistivity of 1 × 10 ¹¹ Ω or more. The method for manufacturing a laminated body according to item 14 of the scope of patent application, wherein the thickness of the foam is 0.05 mm to 0.5 mm.