JP2011068800A - Double-sided tacky adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double-sided tacky adhesive film that has excellent transparency, thins a tacky adhesive layer and has slight environmental load without requiring steps of coating, drying, crosslinking, etc., of a tacky adhesive solution. <P>SOLUTION: The double-sided tacky adhesive film includes a tacky adhesive layer comprising an acrylic block copolymer (A) as a main component composed of a methacrylic polymer block (a) and an acrylic polymer block (b), a release layer comprising a thermoplastic resin (B) as a main component on one side of the tacky adhesive layer and a release layer comprising a thermoplastic resin (C) as a main component on the other side. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a double-sided adhesive film having an adhesive layer made of an acrylic block copolymer and a release layer made of a thermoplastic resin on both sides of the adhesive layer.

  Conventionally, as a double-sided adhesive film, a resin film or foam such as polyester or polyethylene, or a paper or fabric film typified by high-quality paper, coated paper, or non-woven fabric is used as a base material (core material). An adhesive obtained by applying an adhesive on both surfaces of a substrate or impregnating the substrate is known. Double-sided adhesive films are used for various purposes such as fixing building materials and electronic device parts. However, a double-sided adhesive film using a substrate has a problem of low transparency. Further, since it is difficult to reduce the thickness, and particularly in applications for attaching electronic parts, a double-sided adhesive film having a very thin thickness is required, and further improvements have been required (Patent Document 1). ).

  Patent Document 2 discloses a double-sided pressure-sensitive adhesive tape that does not have a substrate. However, the production method is such that a cross-linkable acrylic pressure-sensitive adhesive is applied, dried, and cross-linked on a release film, and then the release film is further bonded. This is a complicated process. In addition, since an organic solvent is used, the environmental load is high, and there are problems such as bleeding and volatilization of a crosslinking agent.

  On the other hand, in recent years, an acrylic block copolymer composed of a methacrylic polymer block and an acrylic polymer block synthesized by living polymerization has been proposed (Patent Document 3). Such an acrylic block copolymer has the characteristics of maintaining the high weather resistance and light resistance inherent to the acrylic polymer while having excellent structure control and narrow molecular weight distribution derived from living polymerization. Moreover, various characteristics can be exhibited by appropriately selecting monomers constituting each polymer block, and development to various uses as an adhesive is expected (Patent Document 4). Also disclosed is a method for producing an adhesive film having an adhesive layer made of an acrylic block copolymer as a surface layer by coextrusion of a thermoplastic resin and an acrylic block copolymer (Patent Document 5). ). However, Patent Document 5 discloses a pressure-sensitive adhesive film having a pressure-sensitive adhesive layer on the outermost surface produced by co-extrusion of a base resin and a pressure-sensitive adhesive resin, and only a release layer on both sides of the pressure-sensitive adhesive layer. No description is given of a double-sided adhesive film having a base material layer having no substrate layer.

JP 2006-302941 A JP 2004-196867 A WO2003 / 068888 JP 2003-105300 A JP2009-125985A

  Provided is a double-sided adhesive film that does not require steps such as coating, drying, and crosslinking of an adhesive solution, is excellent in transparency, and can reduce the adhesive layer and has a low environmental load.

  As a result of intensive studies to solve the above problems, the present invention has been completed.

  That is, the present invention provides an adhesive layer mainly composed of an acrylic block copolymer (A) comprising a methacrylic polymer block (a) and an acrylic polymer block (b), and the pressure-sensitive adhesive layer. The present invention relates to a double-sided adhesive film comprising a release layer mainly composed of a thermoplastic resin (B) on one side and a release layer mainly composed of a thermoplastic resin (C) on the other side.

  As a preferred embodiment, the acrylic block copolymer (A) includes a methacrylic polymer block (a) having a glass transition temperature of 20 ° C. or higher, and an acrylic polymer block having a glass transition temperature of 0 ° C. or lower. It is related with said double-sided adhesive film characterized by consisting of (A).

  As a preferable embodiment, the acrylic block copolymer (A) is a triblock body, a diblock body, or a mixture thereof.

  As a preferred embodiment, the present invention relates to the above double-sided adhesive film, wherein the proportion of the methacrylic polymer block (a) in the acrylic block copolymer (A) is from 10 to 50% by weight.

  As a preferred embodiment, the acrylic polymer block (b) is at least one monomer selected from the group consisting of n-butyl acrylate, ethyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate. It is related with said double-sided adhesive film characterized by including a body.

  As a preferred embodiment, the acrylic block copolymer (A) is a metal having an organic halide or a sulfonyl halide compound as an initiator and at least one selected from Fe, Ru, Ni, and Cu as a central metal. The present invention relates to the above-mentioned double-sided adhesive film produced by an atom transfer radical polymerization method using a complex as a catalyst.

  As a preferred embodiment, the thermoplastic resin (B) and the thermoplastic resin (C) are each independently selected from the group consisting of polyolefin resins, polyester resins, polyvinyl chloride resins, polyamide resins, and polystyrene resins. The present invention relates to the above double-sided adhesive film characterized by comprising at least one selected resin as a main component.

  As a preferred embodiment, the thermoplastic resin (B) and the thermoplastic resin (C) are each independently related to the above double-sided adhesive film, characterized in that the polyolefin resin is a main component.

  As a preferred embodiment, the thermoplastic resin (B) and the thermoplastic resin (C) are each independently composed mainly of at least one resin selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer. It is related with said double-sided adhesive film characterized by becoming.

  As a preferred embodiment, the double-sided adhesive film as described above, wherein the release layer mainly comprising the thermoplastic resin (B) and the release layer mainly comprising the thermoplastic resin (C) are the same. About.

  As a preferred embodiment, the above-mentioned double-sided adhesive film, wherein the release layer mainly comprising the thermoplastic resin (B) and the release layer mainly comprising the thermoplastic resin (C) are different. About.

  Furthermore, this invention relates to the manufacturing method of a double-sided adhesive film characterized by manufacturing said double-sided adhesive film with a co-extruder.

  According to the present invention, it is possible to provide a double-sided adhesive film that is excellent in transparency and capable of thinning an adhesive layer without worrying about organic solvents, crosslinking agents, and residual monomers. Furthermore, the manufacturing method of the present invention does not use an organic solvent, does not require a process such as laminating a release film, and has a simple manufacturing process that does not substantially include foreign matter between layers, and has a low environmental impact. Can provide film.

  Hereinafter, the present invention will be described in detail.

<Double-sided adhesive film>
The double-sided adhesive film of the present invention comprises an adhesive layer mainly composed of an acrylic block copolymer (A) comprising a methacrylic polymer block (a) and an acrylic polymer block (b), The pressure-sensitive adhesive layer has a release layer mainly composed of a thermoplastic resin (B) on one side and a release layer mainly composed of a thermoplastic resin (C) on the other side. By peeling the two release layers, the adhesive layer is exposed and can be used as a double-sided adhesive film that does not have a base material (core material) such as paper, nonwoven fabric, or foam. Problems such as limitations and reduced transparency are eliminated. In addition, a film here shall generally mean the film-like article in general including a tape, a sheet | seat, etc.

<Peeling layer mainly composed of thermoplastic resin>
The double-sided adhesive film of the present invention has a release layer mainly composed of a thermoplastic resin (B) on one side of the adhesive layer and a thermoplastic resin (C) on the other side. The components constituting these two release layers may be the same or different. If the two are the same, the manufacturing process is simplified, which is advantageous in terms of cost, and there is an advantage that it can be used without distinguishing the front and back sides. On the other hand, when the two are different, the case where the distinctiveness is enhanced by the difference in color, the case where the workability is enhanced by the difference in peeling force, the heat resistance, weather resistance, light resistance, chemical resistance, etc. The case where it wants to give to a peeling layer is mentioned.

  It does not specifically limit as a thermoplastic resin (B) and a thermoplastic resin (C), Generally the thermoplastic resin which can be shape | molded in a film form can be used widely. Further, the thermoplastic resin (B) and the thermoplastic resin (C) may be the same or different, and can be used properly according to the purpose. Examples of the thermoplastic resin include polyolefin resin, polyester resin, polyvinyl chloride resin, polyamide resin, acrylic resin, polystyrene resin, polyimide resin, polyvinyl alcohol resin, polycarbonate resin, and ethylene vinyl acetate. Polymer based resins, cellulose based resins and the like can be mentioned, and thermoplastic resins modified with functional groups (carboxylic acid, acid anhydride, epoxy, etc.) are also included. These may be used alone or in combination. Among these, polyolefin resins, polyester resins, polyvinyl chloride resins, polyamide resins, and polystyrene resins are preferable, and polyolefin resins are more preferable from the viewpoint of peelability from the adhesive layer, and film moldability and cost. From the above, polyethylene, polypropylene, and ethylene-propylene copolymer are more preferable.

  Polyolefin resins include polyethylene, ethylene-propylene copolymer, ethylene-propylene-nonconjugated diene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, chlorinated polyethylene. Polyethylene resins such as polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer, polypropylene resins such as chlorinated polypropylene, poly-1-butene, polyisobutylene, polymethylpentene, cyclic olefin ( Examples thereof include (co) polymers. Among these, polyethylene, polypropylene, and ethylene-propylene copolymer can be preferably used from the viewpoint of balance between cost and physical properties.

  Modified polyolefin resins include those obtained by copolymerizing acid anhydrides such as maleic anhydride and fumaric anhydride, and those obtained by copolymerizing unsaturated carboxylic acids such as acrylic acid, methacrylic acid and vinyl acetate, or salts or esters thereof. Is mentioned. Moreover, modified polyolefin resin etc. which melt-modified the polyolefin resin using silyl group containing compounds, such as maleic anhydride, maleic acid, glycidyl methacrylate, vinyl silane, etc. in the presence of a radical initiator etc. are mentioned.

  Specific examples include Bond First 2C, which is an ethylene-glycidyl methacrylate copolymer (Each is manufactured by Sumitomo Chemical Co., Ltd., hereinafter the same), Bond First 2B, which is an ethylene-vinyl acetate-glycidyl methacrylate copolymer, 7B, Bond First 7L, 7M which is an ethylene-methyl acrylate-glycidyl methacrylate copolymer, Admer QE840 (manufactured by Mitsui Chemicals) which is an acid-modified polypropylene, Umex 1001 (manufactured by Sanyo Chemical Co., Ltd.), Ricosen PPMA1332 (Manufactured by Clariant Japan Co., Ltd.), Lycocene PPSI3262TP (manufactured by Clariant Japan Co., Ltd.) which is a silane-modified polypropylene, and Modiper A4100 (EGMA-g-P) which is a polyolefin-vinyl polymer graft copolymer. ), A8100 (E / EA / MAH-g-PS), A4200 (EGMA-g-PMMA), A8200 (E / EA / MAH-g-PMMA), A4400 (EGMA-g-AS), A8400 (E / EA / MAH-g-AS) (all manufactured by NOF Corporation).

  In the thermoplastic resin used for the release layer, generally used pigments, fillers, stabilizers, plasticizers, lubricants, flame retardants and the like can be blended as long as the present invention is not impaired. These may be used alone or in combination.

<Adhesive layer mainly composed of acrylic block copolymer>
The adhesive layer of the double-sided adhesive film of the present invention comprises an acrylic block copolymer (A) composed of a methacrylic polymer block (a) and an acrylic polymer block (b) as a main component. Such an acrylic block copolymer (A) has adhesive properties but is different from solvent-based adhesives, water-based emulsion adhesives, and reaction-curable liquid adhesives. Since it is a solid (pellet) at room temperature, it is very excellent in supply to an extruder and handling, ease of storage and transportation, and storage stability. In general, double-sided adhesive films are generally applied with a solution-type adhesive or water-based emulsion-type adhesive and dried, and then attached with a release film, or with a reaction-curable liquid adhesive. Manufactured in a complicated process of bonding a release film after curing. Since the present invention uses an acrylic block copolymer which is thermoplastic, an organic solvent used for a solution-type adhesive, a crosslinking agent or a residual monomer used for a reaction-curable liquid adhesive, etc. There are no problems such as bleeding or volatilization of the residue.

  The adhesive layer of the double-sided adhesive film of the present invention includes conventionally known tackifiers, plasticizers, softeners, liquid polymers (syrups), fillers, stabilizers, pigments, dyes and the like as optional components. These various additives can be appropriately blended.

  Although it does not specifically limit as a tackifier, For example, rosin resin, modified rosin resin, terpene resin, terpene phenol resin, aromatic modified terpene resin, C5 or C9 petroleum oil, coumarone resin, etc. Is used. When an acrylic block copolymer is used as an adhesive, rosin resin, modified rosin resin, and terpene phenol resin are preferred because of good compatibility. These are appropriately selected in order to adjust the adhesive properties of the adhesive layer, the peel strength between the adhesive layer and the release layer, and the like.

<Acrylic block copolymer>
The acrylic block copolymer (A) constituting the adhesive layer of the double-sided adhesive film of the present invention is mainly composed of a methacrylic polymer block (a) mainly composed of a methacrylic ester and an acrylic ester. The acrylic block copolymer (A) comprising the acrylic polymer block (b) as a component is preferred. The structure of the acrylic block copolymer (A) may be either a linear block copolymer, a branched (star) block copolymer, or a mixture thereof. The structure of such a block copolymer is appropriately selected according to the required physical properties of the acrylic block copolymer (A). However, in terms of cost and ease of polymerization, linear block copolymer Coalescence is preferred.

  The linear block copolymer may have any structure. From the viewpoint of the physical properties of the linear block copolymer and the composition, the methacrylic polymer block (a) is a, acrylic When the polymer block (b) is expressed as b, (ab) n type, b- (ab) n type, and (ab) na type (n is an integer of 1 or more, for example, 1 It is preferable that it consists of an at least 1 sort (s) of acrylic block copolymer selected from the group which consists of -3. Among these, an ab type diblock copolymer, an abb type triblock copolymer, or a mixture thereof is preferable from the viewpoint of easy handling during processing and physical properties of the composition.

  The number average molecular weight (Mn) of the acrylic block copolymer (A) can be appropriately set according to the properties required for the adhesive layer, but is preferably 10,000 to 300,000. If the number average molecular weight is less than 10,000, the adhesive property tends to be reduced and adhesive residue or the like tends to be generated. If the number average molecular weight is more than 300,000, the melt viscosity is too high and the workability and fluidity are reduced. Tend to. In addition, the said number average molecular weight shows the value measured by polystyrene conversion by the gel permeation chromatography (GPC) which uses chloroform as a mobile phase and uses a polystyrene gel column.

  The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the acrylic block copolymer (A) measured by GPC is not particularly limited, but is preferably 1.8 or less. It is more preferably 1.7 or less, and further preferably 1.5 or less. When Mw / Mn exceeds 1.8, the adhesive property may be deteriorated. It is preferable that Mw / Mn is small because problems such as adhesive residue due to low molecular weight components, problems such as deterioration in workability and poor appearance due to high molecular weight components can be reduced.

  The proportion of the methacrylic polymer block (a) in the acrylic block copolymer (A) is preferably 10 to 50% by weight. If the proportion of the methacrylic polymer block (a) is less than 10% by weight, the cohesive force tends to be insufficient and the holding power tends to be lowered, and the shape is difficult to be held and the handling property of the pellet tends to be poor. When the proportion of the methacrylic polymer block (a) is more than 50% by weight, the tackiness tends to be lowered or the workability tends to be lowered.

<Methacrylic polymer block (a)>
The methacrylic polymer block (a) is a block formed by polymerizing a monomer having a methacrylic acid ester as a main component. Here, the main component means that 50% by weight or more of the monomers constituting the methacrylic polymer block (a) is methacrylic acid and / or methacrylic acid ester.

  The glass transition temperature of the methacrylic polymer block (a) is preferably 20 ° C. or higher, and more preferably 50 ° C. or higher. If it is less than 20 ° C., the solid state cannot be maintained at room temperature and the handling property is inferior, and the cohesive force is insufficient and the adhesive properties such as holding force are lowered.

  Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, Methacrylic acid aliphatic hydrocarbons such as n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, stearyl methacrylate (for example, alkyl having 1 to 18 carbon atoms) ) Ester; Methacrylic acid alicyclic hydrocarbon ester such as cyclohexyl methacrylate and isobornyl methacrylate; Aralkyl methacrylate such as benzyl methacrylate; Phenyl methacrylate, Tolu methacrylate Methacrylic acid aromatic hydrocarbon esters such as dimethyl ether; esters of methacrylic acid such as 2-methoxyethyl methacrylate and 3-methoxybutyl methacrylate with functional group-containing alcohols having etheric oxygen; trifluoromethyl methacrylate, methacrylic acid Trifluoromethyl methyl, 2-trifluoromethyl ethyl methacrylate, 2-trifluoroethyl methacrylate, 2-perfluoroethyl ethyl methacrylate, 2-perfluoroethyl-2-perfluorobutyl ethyl methacrylate, 2-methacrylic acid 2- Perfluoroethyl, perfluoromethyl methacrylate, diperfluoromethyl methyl methacrylate, 2-perfluoromethyl 2-perfluoroethyl methyl methacrylate, 2-perfluorohexyl ethyl methacrylate, methacrylate Acid 2-perfluorodecyl ethyl, methacrylic acid fluorinated alkyl esters such as methacrylic acid 2-perfluoroalkyl-hexadecyl ethyl. Among these, methyl methacrylate is preferable. These may be used alone or in combination of two or more.

  The methacrylic polymer block (a) contains a methacrylic acid ester as a main component, but may contain 50 to 0% by weight of a vinyl monomer other than the methacrylic acid ester copolymerizable therewith. Examples of the copolymerizable vinyl monomer include acrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, halogen-containing unsaturated compounds, silicon-containing unsaturated compounds, vinyl ester compounds, and maleimides. Compound etc. can be mentioned.

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate, Acrylic aliphatic hydrocarbons such as n-heptyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, etc. (eg, alkyl having 1 to 18 carbon atoms) ) Esters; Acrylic alicyclic hydrocarbon esters such as cyclohexyl acrylate and isobornyl acrylate; Aromatic aromatic hydrocarbon esters such as phenyl acrylate and toluyl acrylate; Aralkyl acrylates such as benzyl acrylate; Esters of acrylic acid and functional group-containing alcohols having etheric oxygen such as 2-methoxyethyl acrylate and 3-methoxybutyl acrylate; trifluoromethyl methyl acrylate, 2-trifluoromethyl ethyl acrylate, acrylic acid 2 -Perfluoroethylethyl, 2-perfluoroethyl-2-perfluorobutylethyl acrylate, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethyl methyl acrylate, 2-perfluoromethyl acrylate Examples thereof include fluorinated alkyl acrylates such as 2-perfluoroethylmethyl, 2-perfluorohexylethyl acrylate, 2-perfluorodecylethyl acrylate, and 2-perfluorohexadecylethyl acrylate.

  Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, and the like.

  Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.

  Examples of the conjugated diene compound include butadiene and isoprene.

  Examples of the halogen-containing unsaturated compound include vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoropropylene, and vinylidene fluoride.

Examples of the vinyl ester compound include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate, and the like.
Examples of the maleimide compound include maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide and the like.

<Acrylic polymer block (b)>
The acrylic polymer block (b) is a block formed by polymerizing a monomer mainly composed of an acrylate ester. The main component means that 50% by weight or more of the monomers constituting the acrylic polymer block (b) is an acrylate ester.

  The glass transition temperature of the acrylic polymer block (b) is preferably 0 ° C. or lower, and more preferably −20 ° C. or lower. When it is 0 ° C. or higher, the adhesive strength is inferior, and the function as a double-sided adhesive film is lowered.

  As the acrylic ester, the same acrylic ester used in the methacrylic polymer block (a) can be used. Among these, n-butyl acrylate, ethyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate are preferable. These may be used alone or in combination of two or more.

  The acrylic polymer block (b) contains an acrylate ester as a main component, but may contain 50 to 0% by weight of a vinyl monomer other than the acrylate ester copolymerizable therewith. Examples of the different types of copolymerizable vinyl monomers include methacrylic acid esters, aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, halogen-containing unsaturated compounds, silicon-containing unsaturated compounds, and vinyl esters. Examples thereof include a compound and a maleimide compound.

<Functional group>
The acrylic block copolymer (A) constituting the adhesive layer of the double-sided adhesive film of the present invention can have a functional group in at least one polymer block. The functional group can be selected from the group consisting of a carboxyl group, an acid anhydride group, an epoxy group, and a hydroxyl group, and can be one or more.

  These functional groups may be contained in either the methacrylic polymer block (a) or the acrylic polymer block (b), and can be selected according to required characteristics. For example, it is preferably contained in the methacrylic polymer block (a) when heat resistance is required, and the acrylic polymer block (b) when elasticity or adhesive strength to a polar adherend is required. It is preferable that it is contained in.

  The method for introducing a functional group into the acrylic block copolymer (A) is not particularly limited, and a method of copolymerizing a monomer having the functional group, a single unit having a functional group serving as a precursor of the functional group. There is a method in which the functional group is generated by a known chemical reaction after copolymerization of the monomer.

  Examples of the monomer having a carboxyl group include unsaturated carboxylic acid compounds such as (meth) acrylic acid, unsaturated dicarboxylic acid compounds such as maleic acid and fumaric acid, and monoester compounds thereof. In addition, (meth) acryl shall mean acryl or methacryl.

  Examples of the monomer having a functional group that becomes a precursor of a carboxyl group include t-butyl (meth) acrylate, trimethylsilyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylic acid α. , Α-dimethylbenzyl, α-methylbenzyl (meth) acrylate, and the like. After these monomers are polymerized, a carboxyl group can be generated by hydrolysis, acid decomposition, thermal decomposition or the like.

  Examples of the monomer having an acid anhydride group include maleic anhydride.

  Examples of the monomer having a functional group that serves as a precursor of an acid anhydride group include the monomer having a carboxyl group and the monomer having a functional group that serves as a precursor of a carboxyl group. It is done. After these monomers are polymerized, an acid anhydride group can be generated by a dehydration reaction or a dealcoholization reaction.

  Examples of the monomer having an epoxy group include glycidyl (meth) acrylate, 2,3-epoxy-2-methylpropyl (meth) acrylate, (3,4-epoxycyclohexyl) methyl (meth) acrylate, and the like ( Examples include esters of (meth) acrylic acid and alcohols containing an epoxy group; and epoxy group-containing unsaturated compounds such as 4-vinyl-1-cyclohexene 1 and 2 epoxides.

  Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and ethylene oxide of (meth) acrylic acid. Examples include adducts.

<Method for producing acrylic block copolymer (A)>
Although it does not specifically limit as a method to manufacture an acryl-type block copolymer (A), It is preferable to use a control polymerization method. Controlled polymerization methods include living anion polymerization (JP-A-11-335432), polymerization using an organic rare earth transition metal complex as a polymerization initiator (JP-A-6-93060), radical polymerization using a chain transfer agent (special Kaihei 2-45511), a living radical polymerization method and the like.

  Living radical polymerization methods include, for example, a polymerization method using a chain transfer agent such as polysulfide, a polymerization method using a cobalt porphyrin complex, a polymerization method using a nitroxide (WO 2004/014926), and a high-cycle heteroelement compound such as an organic tellurium compound. And the like. (Polymer No. 3839829), Reversible Addition / Desorption Chain Transfer Polymerization (RAFT) (Patent No. 3639859), Atom Transfer Radical Polymerization (ATRP) (Patent No. 3040172), and the like. In the present invention, any of these methods is not particularly limited, but the atom transfer radical polymerization method is preferable from the viewpoint of easy control.

  As a method for producing the acrylic block copolymer (A) using the atom transfer radical polymerization method, for example, the method described in WO2004 / 013192 can be used.

  As the acrylic block copolymer (A) used for the adhesive layer of the double-sided adhesive film of the present invention, in particular, an organic halide or a sulfonyl halide compound is used as an initiator, and Fe, Ru, Ni Those produced by an atom transfer radical polymerization method using a metal complex having at least one selected from Cu as a central metal as a catalyst are preferable in terms of cost and polymerization control.

<Manufacture of double-sided adhesive film>
The production method of the double-sided adhesive film of the present invention is not particularly limited, and general adhesive film forming methods such as a solution coating method, a hot melt coating method, a laminating method, and a coextrusion method can be used. Especially, it is preferable to manufacture by a coextrusion method from points, such as productivity. Co-extrusion is a method of producing a laminate by supplying separate molten resins from two or more extruders and joining them together, and producing a film-like laminate (multilayer film) simply and with high production can do. When producing multilayer films, the T-die method is mainly used. The die shape is a feed block die that joins the molten resin and then discharges into a film shape, or the layers are joined into a film shape in the die. There are multi-manifold dies for discharging. Any of them can be used in the present invention, but the feed block die has an advantage that the equipment is simple and inexpensive.

  In general, a multilayer film produced by coextrusion is characterized in that the layers are firmly bonded to each other because the resins of the respective layers merge in a molten state. However, in the present invention, an adhesive layer mainly composed of the acrylic block copolymer (A), a release layer mainly composed of the thermoplastic resin (B) on one side of the adhesive layer, etc. By laminating a release layer containing the thermoplastic resin (C) as a main component on the surface by coextrusion, a double-sided adhesive film capable of easily peeling each layer can be produced. This eliminates the need for a solvent drying step, a pressure-sensitive adhesive resin curing step, a release film laminating step, and the like in a general manufacturing process of a double-sided adhesive film, thereby improving productivity. In addition, since each layer is formed at the same time, there is substantially no contamination between the layers, and a double-sided adhesive film used for optical film applications can be manufactured without the need for special equipment such as a clean room. it can.

  In order to produce the double-sided adhesive film of the present invention by coextrusion, a composition comprising a thermoplastic resin (B), a composition comprising an acrylic block copolymer (A), and a thermoplastic resin (C). The resulting composition is supplied to separate extruders and discharged into a film using a slit-shaped die. Although the thickness of the obtained multilayer film is not specifically limited, 5-3000 micrometers is preferable. Although the thickness of each layer can be freely set, the release layer is 5 to 300 μm, preferably 5 to 100 μm. A thick release layer is disadvantageous in terms of cost. The adhesive layer is 5 to 1000 μm, preferably 5 to 500 μm, more preferably 5 to 200 μm. If the adhesive layer is thick, the appearance may be poor when the article is attached as a double-sided adhesive film, and if it is thin, the adhesive property may be insufficient.

  The extrusion temperature of the release layer mainly composed of the thermoplastic resin (B) and the thermoplastic resin (C) is preferably 120 to 300 ° C, and more preferably 150 to 250 ° C. When extrusion temperature is low, fluidity | liquidity deteriorates, a sink and distortion are produced in a film, and there exists a possibility that adjustment of a film thickness may become difficult. When the extrusion temperature is high, voids or silver streaks due to thermal decomposition of the thermoplastic resin may occur, or molding defects such as yellowing of the film may occur.

  The extrusion temperature of the adhesive layer mainly composed of the acrylic block copolymer (A) is preferably 120 to 300 ° C, more preferably 150 to 250 ° C. When extrusion temperature is low, fluidity | liquidity deteriorates, a sink and distortion are produced in a film, and there exists a possibility that adjustment of a film thickness may become difficult. If the extrusion temperature is high, voids and silver streaks due to thermal decomposition of the acrylic block copolymer (A) may occur, and molding defects such as yellowing of the film may occur.

  The extrusion temperature of each layer is appropriately selected according to the melt viscosity. If the melt viscosity of each layer is greatly different, the film width may be different in each layer, not only the appearance of the multilayer film is deteriorated, but also the ratio (product yield) of functioning as a double-sided adhesive film is lowered.

  The multilayer film extruded from the die is cooled by being brought into close contact with a cooling roll or an endless belt. You may extend | stretch as needed. Thereafter, the paper is collected by being wound in a roll around a paper tube or a plastic tube.

<Use of double-sided adhesive film>
The double-sided adhesive film of the present invention is characterized in that in addition to the heat resistance, weather resistance, high tackiness, and transparency that are the characteristics of the acrylic block copolymer (A), it can be thinned because there is no substrate. To do. In addition, there are no problems such as bleeding and volatilization of residues such as organic solvents used in solution-type adhesives and cross-linking agents and residual monomers used in reaction-curing liquid adhesives. It can also be suitably used for optical, hygiene and medical applications. In addition, the multilayer film produced by coextrusion is characterized by being clean with no foreign matter at the interface of each layer, and can be suitably used for optical applications.

  Specifically, various metal materials, plastic materials, rubber materials, wood, etc., transparent nameplates, electronic devices, touch panels, etc., optical panels such as flat panel displays, etc. It is preferably used for application to the skin of medical equipment and decorations.

  EXAMPLES Although this invention is demonstrated further in detail based on an Example, this invention is not limited only to these Examples.

<Molecular weight measurement method>
The molecular weight shown in this example was measured by the GPC analyzer shown below, and the molecular weight in terms of polystyrene was determined using chloroform as the mobile phase. As a system, a GPC system manufactured by Waters was used, and Shodex K-804 (polystyrene gel) manufactured by Showa Denko Co., Ltd. was used for the column.

<Method for measuring conversion rate of polymerization reaction>
The conversion rate of the polymerization reaction shown in this example was measured using the following analyzer and conditions.
Equipment used: Gas chromatography GC-14B manufactured by Shimadzu Corporation
Separation column: J & W SCIENTIFIC INC, capillary column DB-17, 0.35 mmφ × 30 m
Separation conditions: Initial temperature 50 ° C., hold for 3.5 minutes
Temperature increase rate 40 ° C / min
Final temperature 140 ° C, hold for 1.5 minutes
Injection temperature 250 ° C
Detector temperature 250 ° C
Sample preparation: The sample was diluted about 10 times with ethyl acetate, and acetonitrile was used as an internal standard substance.

Production Example 1 Production of Acrylic Block Copolymer 1 A nitrogen-substituted 500 L reactor was charged with 80.9 kg of BA and 2.1 kg of TBA as monomers constituting the acrylic polymer block. 580 g of cuprous was charged and stirring was started. Thereafter, a solution prepared by dissolving 583 g of diethyl 2,5-dibromoadipate in 7.3 kg of acetonitrile was charged, and the jacket was heated and held at an internal temperature of 75 ° C. for 30 minutes. Thereafter, 70 g of pentamethyldiethylenetriamine was added to initiate polymerization of the acrylic polymer block. About 100 g of the polymerization solution was extracted from the polymerization solution for sampling at regular intervals from the start of polymerization, and the conversion rate of BA was determined by gas chromatogram analysis of the sampling solution. The polymerization rate was controlled by adding pentamethyldiethylenetriamine as needed.

  When the conversion rate of BA reached 97%, 82.5 kg of toluene, 400 g of cuprous chloride, 70 g of pentamethyldiethylenetriamine, and 35.6 kg of MMA were added as monomers constituting the methacrylic polymer block. Polymerization of the system polymer block was started. When the MMA conversion rate reached 90%, 120 kg of toluene was added to dilute the reaction solution, and the reactor was cooled to terminate the polymerization.

  Toluene was added to the resulting acrylic block copolymer solution to make the polymer concentration 25% by weight. 1.6 kg of p-toluenesulfonic acid monohydrate was added to this solution, the inside of the reactor was purged with nitrogen, and the mixture was stirred at 150 ° C. for 4 hours to convert the t-butyl group of TBA into a carboxyl group. Thereafter, 2.3 kg of Radiolite # 3000 manufactured by Showa Chemical Industry was added as a filter aid, and pressure filtered at 0.1 to 0.4 MPaG using a pressure filter equipped with a polyester felt as a filter medium. Separated the minutes.

  The obtained acidic solution was again put into a 500 L reactor, 3.4 kg of Kyowa Chemical Kyodo 500SH was added as a solid base, and the mixture was stirred at 30 ° C. for 1 hour. Thereafter, using a pressure filter equipped with a polyester felt as a filter medium, the solid content is separated by pressure filtration at 0.1 to 0.4 MPaG, and the target carboxyl group-containing acrylic block copolymer 1 is obtained. Solution was obtained. After adding 0.6 parts by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals) to the obtained polymer solution with respect to the weight of the polymer, SCP100 (manufactured by Kurimoto Steel Works, The solvent component was evaporated using a heat transfer area of 1 m2). The polymer was made into a strand through a φ4 mm die, cooled in a water bath, and polymer pellets were obtained by a pelletizer.

  When the GPC analysis of the obtained acrylic block copolymer 1 was conducted, the number average molecular weight (Mn) was 109,000 and the molecular weight distribution (Mw / Mn) was 1.34.

  This acrylic block copolymer 1 was dissolved in toluene so as to have a solid content concentration of 30% by weight. Using this toluene solution, an adhesive tape was prepared by coating a PET film having a thickness of 50 μm with a coater so that the thickness of the adhesive layer was 30 μm. When this adhesive tape was affixed to a stainless steel plate according to JIS Z-0237 as a width of 25 mm × length of 125 mm, and the adhesive force was measured under conditions of an ambient temperature of 23 ° C., a peeling angle of 180 °, and a tensile speed of 300 mm / min, It was 3.9 N / 25 mm. On the other hand, when the adhesive strength was measured by changing the stainless steel plate to a polypropylene plate, it was 0.4 N / 25 mm, and it can be seen that the acrylic block copolymer 1 has a low adhesive strength to the polyolefin resin.

Example 1
A multilayer film was manufactured using a three-layer film manufacturing apparatus (Toyo Seiki Seisakusho Co., Ltd.) having a screw diameter of 20 mm and L / D = 20. In this three-layer film manufacturing apparatus, three extruders are connected to a feed block die. The lip clearance of the die was set to 300 μm.

  From three extruders, low density polyethylene (Novatech LF441MD: manufactured by Nippon Polyethylene Co., Ltd.), acrylic block copolymer 1, and low density polyethylene (LF441MD) were coextruded so as to be laminated in this order. The screw rotation speed was set to 20 rpm / 50 rpm / 20 rpm in the above order. The extrusion temperature was set to 230 ° C. for all the extruders. The formed multilayer film was rolled up and collected. The thickness of the film was 110 μm / 140 μm / 110 μm in the above order.

  The polyethylene layer on one side is peeled off from the obtained multilayer film, and the exposed adhesive layer made of acrylic block copolymer 1 is pasted on a stainless steel plate according to JIS Z-0237 as a width of 25 mm and a length of 125 mm. When the adhesive force was measured under the conditions of an atmospheric temperature of 23 ° C., a peeling angle of 180 °, and a tensile speed of 300 mm / min, 2.0 N / 25 mm was sufficient, indicating a sufficient adhesive property.

  Also, after affixing a multilayer film from which only one polyethylene layer has been peeled off to a vertically positioned glass surface, the other polyethylene layer is peeled off to expose the layer made of acrylic block copolymer 1, and Then, a PMMA plate (weight 15 g, adhesion area 5 cm × 5 cm) was attached to adhere the glass and PMMA. When kept at room temperature in this state, it did not drop for more than 2 months and adhered.

  From the above results, it was found that this multilayer film can be suitably used as a double-sided adhesive film.

Claims (12)

An adhesive layer mainly composed of an acrylic block copolymer (A) comprising a methacrylic polymer block (a) and an acrylic polymer block (b), and a thermoplastic resin on one side of the pressure-sensitive adhesive layer A double-sided adhesive film comprising a release layer mainly comprising (B) and a release layer mainly comprising a thermoplastic resin (C) on the other surface. The acrylic block copolymer (A) comprises a methacrylic polymer block (a) having a glass transition temperature of 20 ° C. or higher and an acrylic polymer block (A) having a glass transition temperature of 0 ° C. or lower. The double-sided adhesive film according to claim 1. The double-sided adhesive film according to claim 1 or 2, wherein the acrylic block copolymer (A) is a triblock body, a diblock body, or a mixture thereof. The double-sided adhesive film according to any one of claims 1 to 3, wherein the proportion of the methacrylic polymer block (a) in the acrylic block copolymer (A) is 10 to 50% by weight. The acrylic polymer block (b) contains at least one monomer selected from the group consisting of n-butyl acrylate, ethyl acrylate, 2-methoxyethyl acrylate, and 2-ethylhexyl acrylate. The double-sided adhesive film according to any one of claims 1 to 4. Acrylic block copolymer (A) is an atom having an organic halide or sulfonyl halide compound as an initiator and a metal complex having at least one selected from Fe, Ru, Ni and Cu as a central metal as a catalyst. The double-sided adhesive film according to any one of claims 1 to 5, which is produced by a moving radical polymerization method. The thermoplastic resin (B) and the thermoplastic resin (C) are each independently at least one selected from the group consisting of polyolefin resins, polyester resins, polyvinyl chloride resins, polyamide resins, and polystyrene resins. The double-sided adhesive film according to claim 1, comprising a resin as a main component. The double-sided adhesive film according to claim 7, wherein the thermoplastic resin (B) and the thermoplastic resin (C) are each independently composed of a polyolefin-based resin. The thermoplastic resin (B) and the thermoplastic resin (C) are each independently composed mainly of at least one resin selected from the group consisting of polyethylene, polypropylene, and an ethylene-propylene copolymer. The double-sided adhesive film according to claim 8. The double-sided viscosity according to any one of claims 1 to 9, wherein the release layer mainly comprising the thermoplastic resin (B) and the release layer mainly comprising the thermoplastic resin (C) are the same. Adhesive film. The double-sided viscosity according to any one of claims 1 to 9, wherein the release layer mainly comprising the thermoplastic resin (B) is different from the release layer mainly comprising the thermoplastic resin (C). Adhesive film. A method for producing a double-sided adhesive film, wherein the double-sided adhesive film according to any one of claims 1 to 11 is produced by a co-extruder.