JP2010017974A - Multilayered laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer laminate in which metal and wood are firmly bonded.
SOLUTION: A multilayer laminate comprising a metal layer, an adhesive layer and wood in this order, wherein the metal layer and wood are adhered by an adhesive layer, wherein the adhesive layer is made of a modified polyolefin grafted with an unsaturated carboxylic acid. A multilayer laminate in which the modified polyolefin grafted with the unsaturated carboxylic acid contains a gel insoluble in xylene heated to 140 ° C., but its content is less than 0.02% by weight.
[Selection figure] None

Description

  The present invention relates to a multilayer laminate, and more particularly to a multilayer laminate composed of a metal layer, an adhesive layer and wood in this order.

  Molded articles such as vinyl chloride, styrene resin, acrylic resin, etc., which reproduce the high-class feel and texture of wood, such as furniture, interior walls, automobile interior parts, keyboard instrument decorations, etc., sheets, films, etc. are widely used (For example, Patent Document 1). However, since the high-class feel and texture of real wood cannot be reproduced, there is an increasing demand to use the wood itself as a decorative material. In order to reproduce the texture and weight of wood, wood is directly used as metal. There is a strong demand for bonding.

  However, when a liquid adhesive is used to bond wood and metal, the liquid adhesive is uniformly applied over a wide area, and the bonding is completed within the open time from coating to bonding, and bonding is performed after bonding. It was difficult to ensure the uniformity of the layer. Moreover, since wood and metal have greatly different polarities as materials, it is not easy to firmly bond these different materials.

  Therefore, there is a need for a film that can be easily and firmly bonded without special surface treatment to metal and wood at a relatively low temperature in a short time, and a laminate in which wood and metal are bonded by this film. It was.

JP 2004-268373 A

  The present invention has been made in view of the above problems, and an object thereof is to provide a multilayer laminate in which wood and metal are bonded.

  As a result of intensive studies, the inventors of the present invention have found that a film, a sheet, a tape, or the like produced from a specific polyolefin grafted with an unsaturated carboxylic acid is heated at a relatively low temperature under pressure for a short time, thereby forming a metal layer and wood. It has been found that a laminate comprising metal layer / adhesive layer / wood can be produced. That is, the present invention is a multilayer laminate composed of a metal layer, an adhesive layer and wood in this order, wherein the metal layer and wood are adhered by the adhesive layer, and the adhesive layer is modified by grafting an unsaturated carboxylic acid. A multilayer laminate comprising a polyolefin, wherein the modified polyolefin grafted with the unsaturated carboxylic acid contains a gel insoluble in xylene heated to 140 ° C., but its content is less than 0.02% by weight. .

  Hereinafter, the present invention will be described in detail.

  The multilayer laminate of the present invention is composed of a metal layer, an adhesive layer, and wood in this order, and the metal layer and wood are adhered by the adhesive layer.

  The metal layer in the multilayer structure of the present invention is a generic term for flat planar metal molded bodies such as foils, films, sheets, and plate-like bodies made of metal, and three-dimensional molded bodies having a three-dimensional shape. It is shown. There is no restriction | limiting in particular in the thickness in said planar metal molded object. In addition, the three-dimensional molded body referred to here includes those having a specific three-dimensional shape obtained by cutting a metal block. Here, examples of the metal include steel, copper, aluminum, tin-plated aluminum, silver-plated copper, and stainless steel, but this does not limit the present invention, and any metal can be used. Further, the present invention can be similarly applied to a metal whose surface is plated with a different metal.

  Wood in the multilayer laminate of the present invention is a sheet-like product obtained by thinly slicing wood, a molded product obtained by molding natural wood itself into a specific shape, a sheet, a film, solidified crushed wood with a binder, A plate, a molded material formed into a block shape, etc., and these molded products may be subjected to secondary processing such as curved surface processing if necessary. In the case of a sheet or film, for example, The back surface of the sheet or film may be reinforced with Japanese paper, paper, cellulosic polymer, synthetic resin film, or the like by an appropriate method. Here, examples of wood include birch, bamboo, oak, zebra wood, saberi, maple, bird's eye maple, rosewood, ebony, karin, cherry blossom, mahogany, sen, cedar, walnut, bubinka, etc. The present invention is not limited, and can be used without any limitation as long as it can be formed into a molded body having the shape shown above.

  The adhesive layer in the multilayer laminate of the present invention is a layer bonded to a metal layer and wood, and is composed of a modified polyolefin grafted with an unsaturated carboxylic acid (hereinafter referred to as an unsaturated carboxylic acid grafted polyolefin). When the adhesive layer is made of an unsaturated carboxylic acid grafted polyolefin, a laminate having excellent insulating properties, thermal shock properties, and adhesive strength can be produced.

  The unsaturated carboxylic acid grafted polyolefin contains a gel insoluble in xylene heated to 140 ° C., but its content is less than 0.02% by weight. It is good not to contain a gel insoluble in xylene heated to 140 ° C, but even if it contains a gel insoluble in xylene heated to 140 ° C, the content is less than 0.02% by weight. Metal and wood are firmly bonded. When the content of the gel insoluble in xylene heated to 140 ° C. is 0.02% by weight or more, not only the appearance of the product when it is made into a film is greatly impaired, but also the adhesive strength and durability as an adhesive layer depending on the amount of the gel. Such problems as deterioration of mechanical properties such as peeling of the laminate occur.

  The amount of the unsaturated carboxylic acid grafted polyolefin of the unsaturated carboxylic acid grafted polyolefin is not particularly limited. However, in order to maintain sufficient adhesiveness and moderately maintain the melt viscosity of the unsaturated carboxylic acid grafted polyolefin, it is preferably 0.00. It is 1 to 10% by weight, and more preferably 0.5 to 8% by weight.

  The unsaturated carboxylic acid grafted polyolefin is in accordance with the type of raw material polyolefin as described later, for example, unsaturated carboxylic acid grafted polyethylene, unsaturated carboxylic acid grafted ethylene / propylene copolymer, unsaturated carboxylic acid grafted ethylene / butene copolymer. And unsaturated carboxylic acid grafted ethylene / hexene copolymer, unsaturated carboxylic acid grafted ethylene / vinyl acetate copolymer, and unsaturated carboxylic acid grafted polypropylene.

  Examples of the unsaturated carboxylic acid include unsaturated monocarboxylic acids and derivatives thereof, unsaturated dicarboxylic acids and derivatives thereof, and acid anhydrides and derivatives of unsaturated dicarboxylic acids. Examples of unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and the like. Derivatives of unsaturated monocarboxylic acids include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl ( Examples include meth) acrylate, isopropyl (meth) acrylate, and butyl acrylate. Examples of unsaturated dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, citraconic acid, and tetrahydrophthalic acid. Desaturated dicarboxylic acids include monomethyl maleate, dimethyl maleate, monoethyl maleate, and maleic acid. Examples include diethyl, monomethyl fumarate, dimethyl fumarate, monoethyl fumarate, and diethyl fumarate. Examples of the acid anhydrides of unsaturated dicarboxylic acid and derivatives thereof include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride and the like. These may be used alone or in combination of two or more. In particular, from the viewpoint of adhesiveness, maleic anhydride alone or a combination of maleic anhydride and (meth) acrylic acid esters is preferable.

  Examples of the polyolefin include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (L-LDPE), and very low density polyethylene (V-LDPE). It is done. Examples of linear low density polyethylene (L-LDPE) include ethylene-α-olefin copolymers such as ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer. Can be mentioned. Other ethylene copolymers such as ethylene-4-methylpentene-1 resin, ethylene-vinyl acetate copolymer (EVA) and saponified products thereof, ethylene-vinyl alcohol resin (EVOH), ethylene-propylene copolymer (EPM), etc. , Polypropylene homopolymer, polypropylene block copolymer, polypropylene random copolymer, and the like, and chlorinated products of these polyolefins can be used in the same manner.

  The polymerization method for synthesizing these polyolefins may be a generally known method, including high-pressure radical polymerization, medium-low pressure polymerization, solution polymerization, slurry polymerization, etc., and the catalyst used is a peroxide catalyst, Ziegler-Natta. Examples of the catalyst include metallocene catalysts, and polyolefins polymerized with these catalysts can be used.

  The melt mass flow rate (MFR) that is a measure of the molecular weight of the polyolefin is not particularly limited, but it is preferable in order to make the solubility in a solvent good even when heated and to maintain the material strength of the final graft reaction product. It is 0.01-50000 (g / 10min), More preferably, it is 0.01-100 (g / 10min).

  Methods for chlorinating polyolefins are known. For example, a method of chlorinating polyolefins by bringing a solution dissolved in a halogen-based solvent such as carbon tetrachloride into contact with a chlorine-containing gas under ultraviolet irradiation (for example, JP 47-8643), a method of chlorinating olefins by blowing chlorine gas into a slurry in which polyolefin powder is suspended in water (for example, Japanese Examined Patent Publication No. 36-4745), a polyolefin without using a solvent. Is heated above its melting point and brought into contact with chlorine gas in a molten state, whereby a polyolefin is chlorinated without using a radical generator, ultraviolet irradiation or the like (for example, JP-A-3-199206) Is disclosed. The chlorinated polyolefin used in the present invention can be produced by any of these methods, and the production method of the chlorinated polyolefin is not limited.

  The unsaturated carboxylic acid grafted polyolefin used in the multilayer laminate of the present invention can be produced by grafting an unsaturated carboxylic acid onto the polyolefin using a radical generator in a halogen-based solvent. Examples of the halogen solvent include 1,1,2-trichloroethane, chloroform, carbon tetrachloride and the like. When 1,1,2-trichloroethane is used as the halogen-based solvent, commercially available 1,1,2-trichloroethane often contains 0.5 to 2.0% by weight of an alcohol compound and / or an epoxy compound. Is contained as an impurity. Here, the alcohol compound is a compound having a hydroxyl group, and examples thereof include ethyl alcohol and butyl alcohol. The epoxy compound is a compound having an epoxy group, such as 1,2-epoxypropane and 1,2 -Epoxybutane etc. are mentioned. In order to obtain an unsaturated carboxylic acid grafted polyolefin with colorless and transparent, good thermal stability and low gel content, when using 1,1,2-trichloroethane as a solvent, It is preferable to remove in advance the alcohol compound and / or the epoxy compound contained as impurities in 1,1,2-trichloroethane.

  As the radical generator, an azo compound or an organic peroxide is used. Examples of the azo compound include α, α-azobisisobutyronitrile, azobiscyclohexanecarbonitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), and the organic peroxide includes Examples include benzoyl peroxide, acetyl peroxide, t-butyl peroxide, and t-butyl perbenzoate.

  The amount of azo compound or organic peroxide added is not particularly limited, but the product maintains the graft amount of unsaturated carboxylic acid and prevents increase in melt viscosity of the resin to prevent deterioration of moldability. In order to maintain the quality, the amount is preferably 0.05 to 5 parts by weight, more preferably 0.05 to 3 parts by weight with respect to 100 parts by weight of the polyolefin.

  The reaction temperature is not particularly limited, but is preferably 40 to 130 ° C., more preferably 60 to 130 ° C. in order to increase the efficiency of the graft reaction and prevent coloring and crosslinking of the modified polyolefin. The reaction pressure is not particularly limited, but is preferably 0 to 1 MPa, more preferably 0 to 0.7 MPa, in order to graft a sufficient amount of unsaturated carboxylic acid and to suppress the generation of gel to prevent deterioration of quality. is there. In this reaction, depending on the reaction temperature and the type of polyolefin to be reacted, the grafting reaction proceeds from a uniform solution state to a suspended state, but the grafting reaction proceeds in the uniform solution state as much as possible. It is preferable to select the temperature appropriately.

  After completion of the grafting reaction, a stabilizer is added as necessary. Stabilizers are preferably added to eliminate radicals generated during the grafting reaction and stop the grafting reaction. It is preferable to use an antioxidant that is usually added to the polyolefin. For example, a phenolic antioxidant or a phosphorus antioxidant. , Sulfur-based antioxidants, and composite antioxidants thereof are preferably used.

  As the reaction vessel used for the grafting reaction, a vessel used for a batch-type reaction can be used. Any material can be used as long as it can withstand the above reaction temperature and reaction pressure, and the material is usually made of stainless steel. If necessary, it is possible to use a glass lining and fluorine coating treated on the inner surface.

  For separation of the unsaturated carboxylic acid grafted polyolefin produced by the grafting reaction from the solvent, a commonly used method such as a drum dryer, steam distillation, vented extruder or the like can be used, but it is economical to use a drum dryer. Particularly preferred from the use.

  When using a drum dryer as a method for separating the unsaturated carboxylic acid grafted polyolefin from the solvent in the reaction step, after the reaction step, the reaction solution is continuously fed from the reactor to a heated drum dryer. The product is isolated from the polymer solution. The temperature of the drum dryer at this time is preferably in the range of 120 to 200 ° C., more preferably 150 to 165 ° C. in order to suppress the coloring, thermal deterioration and crosslinking of the polymer while promoting drying. The polymer is a thin film that is peeled off from the drum and isolated.

  Further, 1,1,2-trichloroethane volatilized by the drum dryer can be recovered by using a recovery line installed at the upper part of the drum dryer and used again for the reaction.

  The time required for removing the solvent from the polymer solution by the drum dryer varies depending on the type of the solvent to be used and the temperature of the drum dryer, and can be selected as appropriate.

  The isolated polymer can be processed into strings, sheets, strands or chips as required, and these primary shaped polymers can be further uniaxially or biaxially extruded as required. It is also possible to feed to a machine, melt and extrude the polymer, and pelletize by strand cutting or underwater cutting. The extrusion temperature in this case is not particularly limited, but is preferably 100 to 300 ° C., more preferably 150 to 300 ° C. in order to sufficiently melt the used polyolefin and smoothly extrude it, and to further suppress the decomposition and coloring of the polyolefin. 250 ° C.

  Other resins can be blended with the unsaturated carboxylic acid grafted polyolefin. Examples of the other resin include not only the above polyolefin resin not subjected to graft reaction, but also styrene resins such as polystyrene, poly-α-methylstyrene, polystyrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene resin, and the like. Acrylic resins such as acrylic acid and polymethyl methacrylate-polyvinyl chloride resin, polyvinylidene chloride resin, polyamide, polyester, polycarbonate resin, fluorine resin, silicone resin, polyphenylene oxide resin (PPO), polyphenylene sulfide resin (PPS), polyimide, polysulfone, polyethersulfone, polyether-etherketone, polybutylene terephthalate resin (PBT), polyoxymethylene resin (POM), epoxy resin Polyurethanes, urea resins, phenol resins, melamine resins, cellulose, and petroleum resins. If necessary, it is possible to chemically react a reactive functional group or another resin having a terminal group with the unsaturated carboxylic acid group of the present invention, utilizing the physical interaction between these functional groups. Blending is possible. Furthermore, a coupling agent such as a silane coupling agent or a titanium coupling agent can be added as a third component to improve compatibility with other resins, or to improve adhesiveness.

  An elastomer or a rubber component can be blended with the unsaturated carboxylic acid grafted polyolefin. Examples of the elastomer or rubber component include natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, butyl rubber, ethylene-propylene rubber, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, epichlorohydrin rubber, nitrile rubber, and acrylic rubber. , Urethane rubber, silicone rubber, fluorine rubber and the like. In addition, as thermoplastic elastomer (TPE), SBS, SIS and other styrene TPE (SBC), polyolefin TPE (TPO), urethane TPE (TPU), polyester elastomer (TPEE), polymeramide elastomer (TPA), Examples include silicone-based TPE and fluorine-based TPE.

  The following various additives can be mix | blended with unsaturated carboxylic acid graft polyolefin. Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and composite antioxidants thereof. Other stabilizers include organic phosphite stabilizers, thioether stabilizers, hindered amine light stabilizers, and the like. Moreover, as a filler, a spherical filler, a plate-like filler, a fibrous filler etc. are mentioned, for example. Examples of adhesives include liquid and solid bisphenol A epoxy resins, epoxy cresol novolacs, epoxy phenol novolacs and mixtures of bisphenol A epoxy resins and epoxy cresol novolacs or epoxy phenol novolacs, bisphenol F epoxy resins, aliphatic epoxy resins, and the like. Can be mentioned. Examples of the epoxy crosslinking agent include boron trifluoride complex compounds, dicyandiamide, polyamides, and polyamines. Examples of the flame retardant include brominated flame retardants such as ethylene bistetrabromophthalimide, decabromodiphenyl oxide, SAYTEX 8010, tetradecabromodiphenoxybenzene, antimony trioxide, antimony pentoxide, zinc borate, FIREBRAKE ZB, and the like. Flame retardant aids, chlorinated flame retardants such as DECLORONE PLUS, and the like. As a lubricant, higher fatty acid metal salts such as magnesium salts of higher fatty acids such as stearic acid, oleic acid, lauric acid, alkaline earth metal salts such as calcium salts and barium salts, cadmium salts, zinc salts, lead salts, and Alkali metal salts such as sodium salt, potassium salt and lithium salt can be used. Other additives include antistatic agents, colorants, natural oils, synthetic oils, waxes, plasticizers, nucleating agents, heavy metal deactivators, processing aids, waxes, arc inhibitors, alumina, silane treatment And dripping inhibitors such as talc, mica, feldspar and wollastonite. The addition amount of the additive is not particularly limited, but 20 parts by weight to 40 parts by weight with respect to 100 parts by weight of the unsaturated carboxylic acid grafted polyolefin in order to develop the additive effect of the additive and maintain adhesiveness. Part.

  For mixing unsaturated carboxylic acid grafted polyolefin with other resins, elastomer or rubber components, and various additives, commonly used kneading methods can be used. Single screw extruder, twin screw extruder, Brabender internal mixer, Banbury A mixer, roll, kneader, Henschel mixer, V blender, tumbler mixer, or the like can be used.

  The adhesive layer in the multilayer laminate of the present invention can be formed into a film by a molding method for processing an unsaturated carboxylic acid grafted polyolefin with a normal polyolefin resin, blown film molding, cast molding, extrusion lamination molding, calendar molding, sheet molding, Examples include fiber molding, blow molding, injection molding, rotational molding, and coating molding. Moreover, in film forming, if necessary, it is also possible to perform coextrusion molding or multilayer lamination molding using an unsaturated carboxylic acid grafted polyolefin in at least one layer on one side.

  In the production of the multilayer laminate of the present invention, there is no particular limitation on the order of lamination of the metal layer, adhesive layer and wood constituting the multilayer laminate, and the unsaturated carboxylic acid graft polyolefin film which is the adhesive layer is heated on the metal layer. After laminating by the pressure bonding method, a method of adhering wood to this laminate, after manufacturing a thermocompressible wood in which an unsaturated carboxylic acid graft polyolefin film as an adhesive layer is laminated on the back surface of the wood by a thermocompression bonding method, Examples of the method of thermocompression bonding this thermocompressible wood to a metal layer, and a method of thermocompression bonding these in the state where the metal layer, the adhesive layer, and the wood are stacked together in this order are illustrated from the viewpoint of workability. Alternatively, a metal or wood in which an unsaturated carboxylic acid grafted polyolefin film is heat-pressed in advance on one side of the wood is manufactured, and then this metal / polyolefin film is produced. The lamina is adhered to the timber, or two-stage process for laminating the wood / polyolefin film laminate adheres to the metal are preferably used.

  If the metal layer or wood has a flat shape such as a sheet, foil, film, etc., the unsaturated carboxylic acid grafted polyolefin film that becomes the adhesive layer is continuously bonded to the metal layer or wood using an automated process. Thus, a roll-shaped heat-adhesive metal sheet, a heat-adhesive metal film, a heat-adhesive wood sheet and the like can be produced. For example, in the method of bonding by passing a laminating roller for bonding a film to the metal layer, the metal layer can be bonded by a method of preheating near the melting temperature of the bonding layer. On the other hand, a method of thermocompression bonding with a laminator without preheating the metal layer is also possible, and there is no limitation on the laminating method as long as the adhesive layer can be heated to a temperature at which adhesiveness is exhibited. When the metal is preheated, hot air blowing or induction heating can be used. In any case, making use of the unsaturated carboxylic acid grafted polyolefin being thermoplastic makes it easy to automate the production of the laminate. As with the metal layer, wood can be preheated in the adhesion to the unsaturated carboxylic acid grafted polyolefin film, but in this case, there are problems such as volatilization of moisture from the wood and discoloration due to burning. Therefore, the preheating temperature is preferably as low as possible, and 50 to 150 ° C. is suitably used.

  The temperature in the thermocompression bonding of the adhesive layer in the multilayer laminate of the present invention is 40 to 250 ° C. When the temperature is lower than 40 ° C., the adhesive layer may not be sufficiently melted and the adhesive strength may be lowered. When the temperature exceeds 250 ° C., coloring due to thermal deterioration of the adhesive layer may be observed. The deterioration of the adhesive strength may lead to a decrease in adhesive strength. Preferably it is 80-200 degreeC.

  The pressure used for the thermocompression bonding of the adhesive layer in the multilayer laminate of the present invention is not particularly limited as long as the adhesive layer is fused, but the thickness of the layer due to the flow of the adhesive layer is maintained while maintaining the adhesiveness of the adhesive interface. In order to suppress the decrease in the pressure, it is preferably 0.01 to 20 MPa, and more preferably 0.01 to 5 MPa. The pressure at the time of bonding is preferably selected according to the type of adherend.

  The multilayer laminate of the present invention uses an unsaturated carboxylic acid grafted polyolefin that can be firmly bonded to metal and wood as an adhesive layer, so that the metal and wood are firmly bonded to each other, and the multilayer, having a sense of texture, weight, and luxury. A laminated body is provided.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to a following example.

<Raw material>
The following raw materials were used in the examples of the present invention.

(1) EVA
Ethylene / vinyl acetate copolymer: Ultrasen (registered trademark) 751 manufactured by Tosoh Corporation (vinyl acetate content = 28 wt%, MFR = 5.7 g / 10 min, density = 952 kg / m ³ )
(2) L-LDPE
Ethylene / hexene-1 copolymer: Nipolon-Z (registered trademark) ZF230 (MFR = 2.0 g / 10 min, density = 920 kg / m ³ ) manufactured by Tosoh Corporation
(3) Benzoyl peroxide (BPO)
NIPPER B made by NOF Corporation
(4) Di (2-t-butylperoxyisopropyl) benzene (DBPIB)
Perbutyl P manufactured by Nippon Oil & Fat Co., Ltd.
(5) 2,6-di-tert-butyl-p-cresol (BHT)
API Corporation Yoshinox BHT
(6) Maleic anhydride, acrylic acid, 1,1,2-trichloroethane, methanol, dimethylformamide, BHT, 26% sulfuric acid aqueous solution, thymol blue indicator, N / 20 KOH solution is a first grade reagent manufactured by Kanto Chemical Co., Inc. Was used.

(7) Aluminum plate manufactured by Toyo Aluminum Co., Ltd. Count: A1N30H-H18 Thickness: 100 μm
(8) Stainless steel SUS304 753513 manufactured by Nilaco Corporation
(9) Wood Flower Art Yumecontinent Made Ebony Sheet, Karin Sheet, Birds Eye Maple Sheet, Oak Sheet, Zebra Wood Sheet Thickness: 0.3mm
<Acid value>
A polymer sample (1 g) is weighed and dissolved in 100 ml of toluene by heating, and then 10 ml of methanol, 10 ml of dimethylformamide and 0.5 ml of water are added. Subsequently, 1 ml of thymol blue indicator was added, titrated with an N / 20 KOH solution (n-propanol / benzene solution), and the point where the blue-violet color persisted for 1 minute or longer was calculated as the end point.

<Melt Mass Flow Rate (MFR)>
Melt mass flow rate (MFR) is measured according to JISK6922-1 for polyethylene and JISK6924-1 for ethylene vinyl acetate copolymer, using a melt indexer L244 manufactured by Takara Kogyo Co., Ltd. , And measured under conditions of a load of 2.16 kgf.

<Measurement of gel fraction>
After 50 mg of polymer was added to 50 ml of xylene and dissolved at 140 ° C. for 12 hours, this solution was filtered through a 200 mesh stainless steel mesh (75 μm), and the unmelted portion on the wire mesh was dried at 105 ° C. for 5 hours. Calculated.

<Melting extrusion>
A 10-zone twin screw extruder (115 mmφ, L / D = 50) manufactured by Nakatani Machinery Industry with a vent was used.

<Heat cycle test>
Using a thermal shock device TSA-71L-A manufactured by ESPEC CORP., Heat shock was applied to the adhesion test piece for 30 minutes at 85 ° C., 5 minutes at room temperature, and 30 minutes at −40 ° C., and the adhesion piece was peeled off. Etc. were observed.

<Adhesion test>
By using a reciprocating compression molding machine WFA-50 manufactured by Shindo Metal Industry Co., Ltd. as a press molding machine, under the press conditions of heating temperature 150 ° C., pressure 10 MPa, 10 minutes, cooling temperature 30 ° C., pressure 10 MPa, 5 minutes. A press film having a thickness of 100 μm was obtained. The film and adherend molded to a thickness of 100 μm were thermocompression bonded using a heat seal tester TP-701 manufactured by Tester Sangyo Co., Ltd. under the conditions of 180 ° C., 60 seconds, and 0.2 MPa. The adhesive strength was evaluated by a T-type peel test using a Tensilon universal tester RTE-1210 (Orientec Co., Ltd.) as a tensile tester under the condition of a tensile speed (peeling speed) of 300 mm / min.

Example 1
<Production of unsaturated carboxylic acid grafted polyolefin>
5000 parts by weight of 1,1,2-trichloroethane and 2500 parts by weight of a 26% sulfuric acid aqueous solution were placed in a 10-liter flask with a lower mouth and stirred vigorously. After standing at rest, the lower organic layer was extracted. Next, 5 kg of the extracted organic layer and distilled water was placed in a 10-liter flask with a lower mouth and stirred vigorously, and after standing, the operation of extracting the lower organic layer was repeated three times to remove impurities 1-butanol and 1,2 -Excluding epoxy butane. Further, 150 parts by weight of molecular sieves 4A was added to the extracted organic layer, and dehydrated by stirring with a stirrer to obtain purified 1,1,2-trichloroethane (hereinafter referred to as purified TCE).

  A 4-liter glass reaction vessel was charged with 3000 parts by weight of purified TCE, 200 parts by weight of EVA, and 5 parts by weight of maleic anhydride. The temperature of the reactor was raised to 80 ° C., and then maintained at 80 ° C. for 4 hours to uniformly dissolve EVA. During this time, nitrogen gas was introduced into the reactor at a flow rate of 5 liters / minute to eliminate air mixed in the reactor. As a catalyst for the graft reaction, 1.55 parts by weight of BPO was dissolved in 100 parts by weight of purified TCE. After this solution was added all at once to the reactor, a graft reaction was carried out for 3 hours while maintaining the reactor pressure at 1 MPa. After completion of the reaction, the pressure was returned to normal pressure, the temperature of the reactor was lowered to 70 ° C., and 0.06 part by weight of BHT was added as a stabilizer. This solution was poured into a large amount of methanol, and the product maleic anhydride grafted EVA was separated from the solvent.

  The product was analyzed and found to have 1.6% by weight of unsaturated carboxylic acid (maleic anhydride). The gel was 0.012% by weight.

<Production of unsaturated carboxylic acid grafted polyolefin film>
The unsaturated carboxylic acid graft EVA obtained as described above was subjected to heating temperature 150 ° C., pressure 10 MPa, heating time 10 minutes, cooling temperature 30 ° C., pressure 10 MPa, cooling time 5 using a reverse compression molding machine WFA-50. A film having a size of 100 mm × 100 mm and a thickness of 100 μm was obtained by press molding under the condition of minutes. The appearance and properties of the obtained film were good, and no defects such as fish eyes were observed.

<Manufacture of multilayer laminate>
The obtained 100 mm × 100 mm, 100 μm thick film and a 0.3 mm thick ebony sheet with the back side reinforced with Japanese paper are thermocompression bonded under the conditions of pressure 0.1 MPa, temperature 180 ° C. for 1 minute, and heat fusion. An ebony sheet with the properties was obtained. The obtained ebony sheet was overlaid on an aluminum plate having a size of 100 mm × 100 mm and a thickness of 1 mm that had not been subjected to surface treatment, and thermocompression bonded under conditions of a pressure of 0.1 MPa, a temperature of 180 ° C., and 1 minute to obtain a multilayer laminate. . Each layer of the obtained laminate was firmly bonded and heated to 40 to 80 ° C., but no peeling was observed. A peel test piece having the same structure as this laminate was prepared, and a T-type peel test was conducted under the condition of a pulling speed of 300 mm / min. The peel strength between the metal layer and the adhesive layer was excellent at 45 N / 15 mm. The peel strength between the wood and the adhesive layer exceeded the breaking strength of the wood itself. Further, it was confirmed that this laminate was bent at −40 ° C. and no peeling was observed, and it was excellent in low temperature characteristics. In addition, the laminate was a laminate having high adhesion strength without peeling after 200 heat cycle tests.

Example 2
The film of size 100 mm × 100 mm obtained in Example 1 and a 100 μm thick film and a 0.3 mm thick karin sheet whose back surface was reinforced with Japanese paper were subjected to thermocompression bonding under the conditions of pressure 0.1 MPa, temperature 180 ° C. and 1 minute. Thus, a karin sheet having heat fusion properties was obtained. The obtained karin sheet was superimposed on an aluminum plate having a size of 100 mm × 100 mm and a thickness of 1 mm that had not been subjected to surface treatment, and was thermocompression bonded under conditions of a pressure of 0.1 MPa, a temperature of 180 ° C., and 1 minute to obtain a multilayer laminate. . Each layer of the obtained laminate was firmly bonded and heated to 40 to 80 ° C., but no peeling was observed. When a peel test piece having the same structure as this laminate was prepared and a T-type peel test was conducted under the condition of a pulling speed of 300 mm / min, the peel strength between the metal layer and the adhesive layer was excellent at 50 N / 15 mm. The peel strength between the wood and the adhesive layer exceeded the breaking strength of the wood itself. Further, it was confirmed that this laminate was bent at −40 ° C. and no peeling was observed, and it was excellent in low temperature characteristics. In addition, the laminate was a laminate having high adhesion strength without peeling after 200 heat cycle tests.

Example 3
A 4-liter glass reaction vessel was charged with 3000 parts by weight of purified TCE, 200 parts by weight of L-LDPE, and 6 parts by weight of acrylic acid. The reactor was heated to 80 ° C., and then kept at 80 ° C. for 4 hours to uniformly dissolve L-LDPE. During this time, nitrogen gas was introduced into the reactor at a flow rate of 5 liters / minute to eliminate air mixed in the reactor. As a catalyst for the graft reaction, 1.4 parts by weight of BPO was dissolved in 100 parts by weight of purified TCE. After this solution was added all at once to the reactor, a graft reaction was carried out for 3 hours while maintaining the reactor pressure at 1 MPa. After completion of the reaction, the pressure was returned to normal pressure, the temperature of the reactor was lowered to 70 ° C., and 0.06 part by weight of BHT was added as a stabilizer. This solution was poured into a large amount of methanol, and the product, acrylic acid grafted L-LDPE, was separated from the solvent. The product was analyzed and found to have 1.8% by weight acrylic acid. The gel was 0.012% by weight.

  The obtained acrylic acid graft L-LDPE was formed into a film by the same method as in Example 1, and then heat-pressed with a bird's eye maple sheet under the conditions of pressure 0.1 MPa, temperature 180 ° C., 1 minute, and surface treatment was performed. A multilayer laminate was obtained by stacking on an aluminum plate having a size of 100 mm × 100 mm and a thickness of 1 mm, which was not performed, and thermocompression bonding under conditions of pressure 0.1 MPa, temperature 180 ° C., and 40 seconds.

  When a peel test piece having the same structure as this laminate was prepared and a T-type peel test was conducted under the condition of a pulling speed of 300 mm / min, the peel strength between the metal layer and the adhesive layer was excellent at 50 N / 15 mm. The peel strength between the wood and the adhesive layer exceeded the breaking strength of the wood itself. Further, it was confirmed that this laminate was bent at −40 ° C. and no peeling was observed, and it was excellent in low temperature characteristics. In addition, the laminate was a laminate having high adhesion strength without peeling after 200 heat cycle tests.

Example 4
A 4-liter glass reaction vessel was charged with 3000 parts by weight of purified TCE, 200 parts by weight of L-LDPE, and 5 parts by weight of maleic anhydride. The reactor was heated to 80 ° C., and then kept at 80 ° C. for 4 hours to uniformly dissolve L-LDPE. During this time, nitrogen gas was introduced into the reactor at a flow rate of 5 liters / minute to eliminate air mixed in the reactor. As a catalyst for the graft reaction, 1.8 parts by weight of BPO was dissolved in 100 parts by weight of purified TCE. After this solution was added all at once to the reactor, a graft reaction was carried out for 3 hours while maintaining the reactor pressure at 1 MPa. After completion of the reaction, the pressure was returned to normal pressure, the temperature of the reactor was lowered to 70 ° C., and 0.06 part by weight of BHT was added as a stabilizer. This solution was poured into a large amount of methanol, and the product, maleic anhydride grafted L-LDPE, was separated from the solvent. The product was analyzed and found to have 1.4 wt% maleic anhydride. The gel was 0.014% by weight.

  The obtained maleic anhydride grafted L-LDPE was formed into a film by the same method as in Example 1, and then thermocompression bonded with a zebrawood sheet under the conditions of a pressure of 0.1 MPa, a temperature of 150 ° C. and 30 seconds, and a thickness of 1 mm. A multilayer laminate was obtained by thermocompression bonding with a stainless steel plate under the conditions of pressure 0.1 MPa, temperature 180 ° C., and 60 seconds.

  A peel test piece having the same structure as this laminate was prepared, and a T-type peel test was conducted under the condition of a pulling speed of 300 mm / min. The peel strength between the metal layer and the adhesive layer was excellent at 45 N / 15 mm. The peel strength between the wood and the adhesive layer exceeded the breaking strength of the wood itself. Further, it was confirmed that this laminate was bent at −40 ° C. and no peeling was observed, and it was excellent in low temperature characteristics. In addition, the laminate was a laminate having high adhesion strength without peeling after 200 heat cycle tests.

Example 5
The acrylic acid graft L-LDPE film obtained in Example 3 was thermocompression bonded with an oak sheet having a thickness of 0.3 mm under the conditions of a pressure of 0.15 MPa, a temperature of 160 ° C., and 30 seconds, and a stainless steel having a thickness of 1 mm. A multilayer laminate was obtained by thermocompression bonding with a steel sheet under the conditions of pressure 0.1 MPa, temperature 170 ° C. and 70 seconds.

  A peel test piece having the same configuration as this laminate was prepared and a T-type peel test was conducted under the condition of a pulling speed of 300 mm / min. The peel strength between the metal layer and the adhesive layer was excellent at 44 N / 15 mm. The peel strength between the wood and the adhesive layer exceeded the breaking strength of the wood itself. Further, it was confirmed that this laminate was bent at −40 ° C. and no peeling was observed, and it was excellent in low temperature characteristics. In addition, the laminate was a laminate having high adhesion strength without peeling after 200 heat cycle tests.

Comparative Example 1
Using a 115mmφ, L / D = 50 twin screw extruder manufactured by Nakatani Machinery Industry, set zones C1, C2, and C3 to 150, 180, and 200 ° C, and zones C4 to C10, A, and D to 220 ° C. The unreacted unsaturated carboxylic acid was removed from the vent between C6 and C7 at a rotation speed of 110 rpm, and a graft reaction was performed. That is, a pre-blend uniformly mixed using a Henschel mixer at a ratio of 100 parts by weight of EVA, 3.6 parts by weight of maleic anhydride and 2 parts by weight of DBPIB was supplied to a twin screw extruder, and grafted to maleic anhydride. EVA was obtained. The resulting EVA contained 0.6 wt% maleic anhydride and contained 0.10 wt% gel.

  Using the compression-type compression molding machine WFA-50, the obtained maleic anhydride graft EVA was heated at a temperature of 160 ° C., a pressure of 10 MPa, a heating time of 10 minutes, a cooling temperature of 30 ° C., a pressure of 10 MPa, and a cooling time of 5 minutes. A film having a thickness of 110 μm was obtained by press molding.

  The obtained EVA grafted with maleic anhydride was formed into a film by the same method as in Example 1, and then thermocompression bonded with an ebony sheet under the conditions of a pressure of 0.1 MPa, a temperature of 150 ° C., and 30 seconds. The multilayer laminate was obtained by stacking on an aluminum plate and thermocompression bonding under conditions of pressure 0.1 MPa, temperature 180 ° C., and 1 minute.

  When a peel test piece having the same structure as this laminate was prepared and a T-type peel test was conducted under the condition of a pulling speed of 300 mm / min, the peel strength between the metal layer and the adhesive layer was excellent at 50 N / 15 mm. The peel strength between the wood and the adhesive layer exceeded the breaking strength of the wood itself. However, when this laminate was bent at −40 ° C., partial peeling was observed. In addition, in this laminate, a part of the aluminum plate was peeled off in 50 heat cycle tests, and the adhesiveness was clearly inferior to the examples.

Comparative Example 2
L-LDPE grafted with maleic anhydride was obtained in the same manner as in Comparative Example 1. That is, L-LDPE 100 parts by weight, maleic anhydride 4.0 parts by weight, DBPIB 2.2 parts by weight of the pre-blend uniformly mixed using a Henschel mixer is supplied to the twin screw extruder, zone C1, C2, C3 is set to 150, 180, 200 ° C, zones C4 to C10, A, D are set to 220 ° C, and unreacted maleic anhydride is removed from the vent between C6 and C7 at a rotation speed of 110 rpm. went. The resulting maleic anhydride grafted L-LDPE contained 0.4 wt% maleic anhydride and contained 0.13 wt% gel.

  The obtained maleic anhydride grafted L-LDPE was subjected to a heating compression temperature of 170 ° C., a pressure of 10 MPa, a heating time of 10 minutes, a cooling temperature of 30 ° C., a pressure of 10 MPa, and a cooling time of 5 minutes. A film having a thickness of 100 μm was obtained by press molding under the conditions described above.

  The obtained L-LDPE grafted with maleic anhydride was formed into a film by the same method as in Comparative Example 1, and then heat-pressed with a bird's eye maple sheet under the conditions of pressure 0.1 MPa, temperature 150 ° C., 30 seconds, A multilayer laminate was obtained by stacking on an aluminum plate having a thickness of 1 mm and thermocompression bonding under conditions of pressure 0.1 MPa, temperature 180 ° C., and 1 minute.

  When a peel test piece having the same structure as this laminate was prepared and a T-type peel test was conducted under a tensile speed of 300 mm / min, the peel strength between the metal layer and the adhesive layer was excellent at 43 N / 15 mm. The peel strength between the wood and the adhesive layer exceeded the breaking strength of the wood itself. However, when this laminate was bent at −40 ° C., partial peeling was observed, and in this laminate, the aluminum plate was partially peeled after 100 heat cycle tests. It was inferior to.

Claims (3)

A multilayer laminate composed of a metal layer, an adhesive layer and wood in this order, wherein the metal layer and wood are adhered by an adhesive layer, the adhesive layer comprising a modified polyolefin grafted with an unsaturated carboxylic acid, A multilayer laminate in which a modified polyolefin grafted with a saturated carboxylic acid contains a gel insoluble in xylene heated to 140 ° C., but its content is less than 0.02% by weight. The multilayer laminate according to claim 1, wherein the metal layer and the wood are bonded by the adhesive layer by heat-pressing the metal layer and / or the wood and the adhesive layer. The multilayer laminate according to claim 1 or 2, further comprising 20 to 40 parts by weight of a flame retardant with respect to 100 parts by weight of the modified polyolefin grafted with an unsaturated carboxylic acid.