TW201425510A - Flame-retardant adhesive composition and flame-retardant adhesive sheet - Google Patents

Abstract

The present invention provides a flame-retardant adhesive composition using a flame retardant, said composition having flame retardancy without adding a halide, maintaining adhesive properties even at high temperatures, and allowing a homogenous coating solution of the flame-retardant adhesive composition to be easily prepared. A flame-retardant adhesive composition characterized by containing a (meth)acrylate polymer (A) and a nitrogenous phosphate-based flame retardant (B), the nitrogenous phosphate-based flame retardant (B) content being 20-50 parts by mass to 100 parts by mass of the (meth)acrylate polymer (A), and fulfiling the following requirements (1) and (2): (1) The (meth)acrylate polymer (A) contains 70-93% by weight of a (meth)acrylic acid alkyl ester (a) having a C1-12 alkyl group, and 7-30% by mass of a vinyl compound (b) having a carboxyl group in the molecule, as a monomer component when polymerizing. (2) The mass retention rate of the flame-retardant adhesive composition at 600 DEG C is 20% or higher in thermogravimetric measurements under a nitrogen atmosphere.

Description

Flame retardant adhesive composition and flame retardant adhesive sheet

The present invention relates to a flame retardant adhesive composition and a flame retardant adhesive sheet. More specifically, it is a flame retardant adhesive composition and a flame retardant adhesive sheet which are excellent in flame retardancy and excellent in initial adhesion and adhesion.

Conventionally, a conventional adhesive label is used as an adhesive sheet attached to a management label on an electronic component or the like. In recent years, it has been demanding flame retardant specifications for electronic components, and the label is also requiring flame retardancy.

In the past, the electrical insulation tape used for electronic components and the like is required to have a high flame retardancy of the VTM-0 level of the UL94 standard in terms of safety.

Therefore, as a method of improving the flame retardancy of the adhesive composition in an electric insulating tape or the like, a method of containing a flame retardant is generally employed for the adhesive composition.

Further, the flame retardant is generally a halogen compound such as chlorine or bromine, or a halogen compound or a cerium oxide.

However, the halogen-based flame retardant has a problem that it is difficult to use because it generates a halogen-based gas during combustion and is harmful to the human body.

Therefore, in order to solve such problems, a method of using a phosphate-based flame retardant as a flame retardant other than a halogen compound has been proposed.

For example, Patent Document 1 discloses a flame-retardant adhesive tape comprising an adhesive layer containing an aromatic condensed phosphate-based flame retardant α and a phosphate β on at least one side of a substrate, with respect to the adhesive. 100 parts by weight of the base polymer in the layer, α + β is 45 to 250 parts by weight, and α / β is a flame retardant adhesive tape blended in a manner of 0.3 to 3.

Further, Patent Document 2 discloses a flame retardant adhesive, which is a kit

Flame-retardant adhesion of acrylic polymer (A), isocyanate-based curing agent (B) and phosphonate (C) of specific structure containing at least 0.1 to 15% by mass of carboxyl group-containing monomer (a) The agent contains 30 to 70 parts by mass of the phosphonate (C) based on 100 parts by mass of the acrylic polymer (A), and the phosphonate (C) has an average particle diameter of 0.1 to 20 μm.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-323269

[Patent Document 2] Japanese Laid-Open Patent Publication No. 2012-149183

However, the present inventors have noticed that the flame-retardant adhesive sheet disclosed in Patent Document 1 has a problem that it is difficult to obtain a balance between the opposite characteristics of flame retardancy and adhesion. In other words, when a large amount of an aromatic phosphate-based flame retardant or an aromatic condensed phosphate-based flame retardant is added in order to achieve flame retardancy, the plasticizer can be plasticized at a high temperature due to the plasticizing effect of the flame retardant, and the adhesive softens. The adhesive properties are reduced.

On the other hand, in Patent Document 2, it is made as a flame retardant component. The phosphonate used is in the form of particles, and if the particulate phosphonate is contained in a large amount, it is difficult to uniformly disperse the coating liquid of the flame retardant adhesive. Further, if a large amount of the flame retardant is not used, there is a problem that sufficient flame retardancy or the like is not obtained.

The present invention has been made in such a situation, and it is an object of the present invention to provide a flame-retardant property without adding a halogen compound, and to maintain adhesive properties even at a high temperature, and to prepare a homogeneous coating liquid using a flame retardant adhesive composition as A flame retardant adhesive composition of an easy flame retardant, and a flame retardant adhesive sheet using the same.

In order to achieve the above object, the inventors of the present invention repeated the intensive research and obtained the following knowledge findings.

Found in a flame retardant adhesive composition comprising a (meth) acrylate polymer and a flame retardant, the flame retardant comprises a nitrogen-containing phosphate-based flame retardant, and the content thereof is made into a specific range, and As a monomer component of the (meth) acrylate polymer, a specific alkyl (meth) acrylate is contained in a specific ratio, and a vinyl compound having a carboxyl group in the molecule, particularly acrylic acid, and maintained at 600 ° C A flame retardant adhesive composition having a rate of 20% or more is suitable for the purpose.

The present invention has been completed on the basis of such knowledge.

That is, the present invention provides the following [1] to [6].

[1] A flame retardant adhesive composition comprising (A) a (meth) acrylate polymer and (B) a nitrogen-containing phosphate-based flame retardant, relative to 100 parts by mass (A) The (meth) acrylate polymer, (B) the content of the nitrogen-containing phosphate-based flame retardant is 20 to 50 parts by mass, and the following requirements (1) and (2) are satisfied: (1) The (A) (meth) acrylate polymer contains 70 to 93% by mass of (a) an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms, and 7 to 30% by mass ( b) a vinyl compound having a carboxyl group in the molecule as a monomer component during polymerization; (2) a thermogravimetric measurement in a nitrogen atmosphere, the mass retention rate of the flame retardant adhesive composition at 600 ° C is 20% or more .

[2] The flame retardant adhesive composition according to [1] above, which further comprises (C) a crosslinking agent.

[3] The flame retardant adhesive composition according to [1] or [2] above, wherein (B) the flame retardant is an ammonium phosphate-based flame retardant.

[4] A flame-retardant adhesive sheet characterized in that the adhesive layer of the flame-retardant adhesive composition according to any one of the above [1] to [3] is laminated on at least one side of the substrate.

[5] The flame-retardant adhesive sheet according to [4] above, wherein the thickness of the adhesive layer is 5 to 30 μm.

[6] The flame-retardant adhesive sheet according to the above [4] or [5] wherein the substrate has a flame retardancy in accordance with the test VTM-0 specified in the UL94 specification.

According to the present invention, it is possible to provide a flame retardancy which is easy to ignite without adding a halogen compound, and maintains an adhesive property even at a high temperature, and which is prepared by using a homogeneous coating liquid of a flame retardant adhesive composition. Adhesive composition, and a flame retardant adhesive sheet using the same.

1a, 1b, 1c‧‧‧ flame retardant adhesive sheets

11‧‧‧Substrate

12a, 12b‧‧‧Adhesive layer

13a‧‧‧ peeling film

Fig. 1 is a view showing the constitution of the flame-retardant adhesive sheet of the present invention. A schematic cross-section of a flame retardant adhesive sheet.

[Formation of the Invention]

[flame retardant adhesive composition]

The flame retardant adhesive composition of the present invention is characterized by comprising (A) a (meth) acrylate polymer and (B) a nitrogen-containing phosphate-based flame retardant, relative to 100 parts by mass of (A) (A) (meth) acrylate polymer, (B) nitrogen-containing phosphate-based flame retardant content of 20 to 50 parts by mass, and meet the following requirements (1) and (2): (1) (A) (methyl The acrylate polymer contains 70 to 93% by mass of (a) an alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms, and 7 to 30% by mass of (b) a vinyl group having a carboxyl group in the molecule. The compound is used as a monomer component during polymerization; (2) In the thermogravimetric measurement under a nitrogen atmosphere, the mass retention of the flame retardant adhesive composition at 600 ° C is 20% or more.

Here, in the above (2), "the mass retention rate of the flame retardant adhesive composition at 600 ° C in the thermogravimetric measurement in a nitrogen atmosphere is 20% or more" means a flame retardant adhesive composition. In a nitrogen atmosphere (nitrogen flow rate: 100 ml/min), the temperature was raised to 600 ° C at a temperature increase rate of 20 ° C / min, and the mass after heating was regarded as "residual mass", and the composition of the flame retardant adhesive was heated. When the former mass is regarded as "initial quality", the mass retention ratio expressed by the following formula is 20% or more.

Quality retention rate (%) = (residual quality / initial quality) × 100

The quality retention ratio of the flame retardant adhesive composition is preferably 21% from the viewpoint of coexisting the flame retardancy with the adhesive properties at normal temperature and high temperature. Above, it is more preferably 22% or more, and particularly preferably 24% or more. The mass retention ratio can be specifically measured by the method described in the examples.

[(A) (meth) acrylate polymer]

The flame retardant adhesive composition of the present invention (hereinafter also referred to simply as "adhesive composition") contains (B) a nitrogen-containing phosphate-based flame retardant and (A) (meth) acrylate described later. polymer.

In the following description, for example, "(meth)acrylic acid" means both acrylic acid and methacrylic acid, and other similar terms are also the same.

(A) The (meth) acrylate polymer contains (a) an alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms in a ratio of 70 to 93% by mass, and a ratio of 7 to 30% by mass. The (b) vinyl compound having a carboxyl group in the molecule is contained as a monomer component at the time of polymerization.

Examples of the (meth)acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms as the monomer component (a) include methyl (meth)acrylate, ethyl (meth)acrylate, and (methyl). Propyl acrylate, butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ( Isooctyl methacrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, and the like. Among these, from the viewpoint of the stability of the adhesive property, etc., butyl (meth)acrylate is preferable, and butyl acrylate is particularly preferable.

When the (meth)acrylic acid alkyl ester having an alkyl group having 13 or more carbon atoms is used as the monomer component (a), the glass transition temperature of the (A) (meth) acrylate polymer becomes too high. Not getting enough adhesion.

On the other hand, as a monomer component (b), there is a carboxy group in the molecule. Specific examples of the vinyl compound of the group include (meth)acrylic acid, β-carboxyethyl acrylate, itaconic acid, crotonic acid, fumaric acid, maleic acid, and monobutyl maleate. Not limited by this. Among these, (meth)acrylic acid is preferable, and acrylic acid is especially preferable.

(A) The (meth) acrylate polymer may be used by using the monomer component (a) in an amount of 70 to 93% by mass, preferably 75 to 92% by mass, and preferably 7 to 30% by mass, preferably 7 to 30% by mass. The monomer component (b) is used in a ratio of 8 to 25% by mass, and is copolymerized by a known method. The form of the copolymer is not particularly limited and may be any of random, block, and graft copolymers.

In addition, when the ratio of use of the monomer component (a) and the monomer component (b) is out of the above range, it is difficult to obtain a mass retention ratio of the obtained adhesive composition at 600 ° C of 20% or more, and it is impossible to obtain The desired adhesiveness.

Further, in addition to the monomer component (a) and the monomer component (b), other monomer component (c) may be contained to the extent that the effects of the present invention are not impaired. The other monomer component (c) is not particularly limited as long as it is a vinyl monomer copolymerizable with the monomer component (a) and the monomer component (b), and examples thereof include styrene and α-A. Styrene, vinyl toluene, vinyl formate, vinyl acetate, acrylonitrile, and the like.

The polymerization method of the (A) (meth) acrylate polymer is not particularly limited, and may be any of solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization, but is preferably solution polymerization and emulsion polymerization.

The weight average molecular weight of the (A) (meth) acrylate polymer is preferably from 300,000 to 1,200,000, more preferably from 400,000 to 800,000, and particularly preferably from 500,000 to 700,000. Gel permeation chromatography (GPC) The value of the standard polystyrene conversion measured.

[(B) Nitrogen-containing phosphate-based flame retardant]

The adhesive composition of the present invention comprises the above (A) (meth) acrylate polymer and (B) a nitrogen-containing phosphate-based flame retardant. By using (B) a nitrogen-containing phosphate-based flame retardant as a flame retardant, the preparation of a homogeneous coating liquid of a flame-retardant adhesive composition becomes easy. Further, it is possible to obtain a flame retardant adhesive composition which is flame retardant without adding a halogen compound and which maintains adhesive properties even at a high temperature.

As the nitrogen-containing phosphate-based flame retardant, an ammonium phosphate-based flame retardant such as ammonium phosphate or ammonium polyphosphate is preferably used.

Further, examples of the nitrogen-containing phosphate-based flame retardant other than the ammonium phosphate system include melamine phosphate, dimelamine phosphate, melamine pyrophosphate, melamine polyphosphate, phosphamide, ruthenium phosphate, and the like. These nitrogen-containing phosphate compounds may be used alone or in combination of two or more.

In the flame retardant adhesive composition of the present invention, the content of the (B) nitrogen-containing phosphate-based flame retardant is 20 to 50 with respect to 100 parts by mass of the above (A) (meth) acrylate polymer. Parts by mass. When the content is less than 20 parts by mass, the flame retardancy is insufficient. On the other hand, if it exceeds 50 parts by mass, the adhesive properties at normal temperature and high temperature are lowered. The content is preferably 25 to 45 parts by mass, more preferably 28 to 42 parts by mass.

In the flame retardant adhesive composition of the present invention, (B) a flame retardant other than the nitrogen-containing phosphate-based flame retardant may be used insofar as the effect of the present invention is not impaired, and the content is relative to 100 parts by mass of the (A) (meth) acrylate polymer, preferably 0 to 35 parts by mass, more preferably 0 to 28 The amount is preferably from 0 to 14 parts by mass, particularly preferably from 0 parts by mass.

The adhesive composition of the present invention may further comprise (C) a crosslinking agent.

[(C) Crosslinker]

In the above (A) (meth) acrylate polymer, a carboxyl group-containing vinyl compound unit can function as a crosslinking point. As a crosslinking agent of the polymer having such a crosslinking point, an isocyanate crosslinking agent, a metal chelate crosslinking agent, a carbodiimide crosslinking agent, an epoxy crosslinking agent, and a nitrogen-acrylic acid can be used. As the pyridine crosslinking agent or the like, an isocyanate crosslinking agent is preferably used.

Examples of the isocyanate crosslinking agent include toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, benzodimethyl diisocyanate, hydrogenated dimethyl diisocyanate, and diphenylmethane. Polyisocyanate compounds such as isocyanate, hydrogenated diphenylmethane diisocyanate, tetramethyl dimethyl diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate; and such polyisocyanates An adduct of a compound with a polyol compound such as trimethylolpropane; a biuret or isomeric cyanate of such a polyisocyanate compound; and such a polyisocyanate compound and a well-known polyether polyol Or an adduct of a polyester polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol, or the like.

Among these isocyanate-based crosslinking agents, from the viewpoint of physical properties as an adhesive, it is preferably selected from the group consisting of 4,4'-diphenylmethane diisocyanate and 2,4-toluene diisocyanate. 6-toluene diisocyanate, hexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, and one or more of these modified bodies, particularly preferably 2,4- Toluene A modified body of cyanate ester.

The isocyanate crosslinking agent is preferably used in a proportion of 0.01 to 10 parts by mass based on 100 parts by mass of the (meth) acrylate polymer.

(other ingredients)

In the adhesive composition, other components may be blended insofar as the effects of the present invention are not impaired. Examples of other components include an ultraviolet absorber, an antioxidant, a preservative, an antifungal agent, a plasticizer, an antifoaming agent, and a wettability adjuster.

Next, the flame-retardant adhesive sheet of the present invention (hereinafter also referred to simply as "adhesive sheet") will be described.

[flammable adhesive sheet]

The flame-retardant adhesive sheet of the present invention is characterized in that an adhesive layer of the above-described flame retardant adhesive composition of the present invention is laminated on at least one side of a substrate.

The adhesive sheet of the present invention is not particularly limited as long as it has the adhesive layer on one or both sides of the substrate.

Fig. 1 is a view showing an aspect of the constitution of the adhesive sheet of the present invention. The adhesive sheet of the present invention is not limited to the adhesive sheet 1a having the adhesive layer 12a on one surface of the substrate 11 as shown in Fig. 1(a), and may be as shown in Fig. 1(b) on the substrate 11. On the adhesive layer 12a formed on one side, the adhesive sheet 1b of the release sheet 13a is further laminated.

Further, the adhesive sheet of the present invention may have an adhesive sheet 1c having adhesive layers 12a and 12b on both sides of the substrate 11 as shown in Fig. 1(c), or may be on each of the adhesive layers 12a and 12b. The adhesive sheets of the release sheets 13a and 13b are laminated. Furthermore, in the first figure (c), the representation of the release sheets 13a and 13b It is omitted.

[substrate]

The substrate used in the adhesive sheet of the present invention is preferably one which has a flame retardancy which is in compliance with the test VTM-0 specified in the UL94 specification. In the present invention, the "test VTM-0 in accordance with the UL94 specification" refers to the vertical burning test of the thin material of the flame retardant test specification UL94 issued by the plastics laboratory company (UNDERWRITERS LABORATORIES INC.). In the test specified in the method, the VTM level was judged as VTM-0.

As such a substrate, a substrate composed of a resin having flame retardancy with a resin monomer, a substrate composed of a resin containing a flame retardant, and a base formed by coating or laminating the resin on a sheet can be used. Materials, metal foils, etc. In the present invention, it is preferred to use a substrate made of a resin.

Examples of the resin having a flame retardancy in a resin monomer include a polyimide imine resin such as a polyether fluorene imine resin or a polyphenylene quinone imide resin, a polyarsenamide resin, a polyphenylene sulfide resin, and a polyether. Ether ketone resin and the like.

Examples of the resin used for the substrate made of a resin containing a flame retardant include a polycarbonate resin, a polystyrene resin, a polyethylene resin, and a polyether in addition to the above-mentioned resin having a flame retardancy. Ester resin, polyolefin resin, polyurethane resin, phenol resin, urea resin, EVA resin, acrylic resin, acrylonitrile butadiene styrene resin (ABS resin), epoxy resin, polystyrene-polycarbonate Ester blend resin, polystyrene-ABS blend resin, polyamide resin, and the like.

Examples of the flame retardant include a phosphorus-based flame retardant, a polysulfonium-based compound, a melamine-based compound, a hindered amine-based compound, an anthraquinone-based compound, and the like. An organic flame retardant, or an inorganic flame retardant such as a lanthanoid compound or a metal hydroxide. The above-mentioned flame retardant may be used singly or in combination of two or more kinds.

Further, a substrate obtained by coating or laminating a resin having a flame retardancy of a resin monomer or a resin containing a flame retardant on a sheet may be used. Examples of the sheet include a sheet-like plastic, a paper such as impregnated paper, a woven fabric, a non-woven fabric, and the like.

Among the above substrates, from the viewpoint of flame retardancy, it is preferably composed of a polyimide resin, a polyarylamine resin, a polycarbonate resin, a polyphenylene sulfide resin, or a polyetheretherketone resin. The substrate or a substrate obtained by coating the resin on the sheet.

Further, from the viewpoint of environmental compatibility, a substrate which does not substantially contain a halogen-based flame retardant is preferable, and a substrate which does not substantially contain any flame retardant is more preferably used.

Specific examples of the substrate used in the adhesive sheet of the present invention include Lumirror ZV10 (trade name, a film coated with a polyimide resin on a polyethylene terephthalate film, Toray Co., Ltd. Co., Ltd.), Torelina (trade name, polyphenylene sulfide resin film, manufactured by Toray Industries, Inc.), Mictron (trade name, polyarsenamide resin film, manufactured by Toray Industries, Inc.), Kapton (trade name, poly醯imino resin film, manufactured by Toray-DuPont Co., Ltd.), Super UT (trade name, polyether phthalimide resin film, manufactured by Mitsubishi Plastics Co., Ltd.), Daiarami (trade name, containing flame retardant) A polyethylene terephthalate resin film, manufactured by Mitsubishi Plastics Co., Ltd., and the like.

Further, LAXRON Polyca SDB-3 (trade name, polycarbonate resin film containing flame retardant, TOKIWA Electric Co., Ltd.) , Sunloid Barrier (trade name, polyphenylene ether resin film, manufactured by Sumitomo BAKELITE Co., Ltd.), Sunloid Ecosheet Polyca (trade name, polycarbonate resin film containing non-halogen flame retardant, manufactured by Sumitomo BAKELITE Co., Ltd. ), Ultem (trade name, polyether phthalimide resin film, manufactured by Asahi Glass Co., Ltd.), Lexan (trade name, polycarbonate resin sheet, manufactured by Asahi Glass Co., Ltd.), Valox (trade name, poly-p-phenylene) A butadiene succinate resin film, manufactured by Asahi Glass Co., Ltd., and a safety film (trade name, polyethylene resin film, manufactured by Omachi Industrial Co., Ltd.). Furthermore, it is not limited by the product examples of these.

The thickness of the substrate can be appropriately determined depending on the use of the adhesive sheet, and is usually 1 to 100 μm, preferably 5 to 100 μm, more preferably 10 to 80 μm.

[Adhesive layer]

The pressure-sensitive adhesive sheet of the present invention is formed by laminating at least one surface of the above-mentioned base material with an adhesive layer formed by using the flame-retardant adhesive composition of the present invention.

In the adhesive sheet of the present invention, the thickness of each side of the adhesive layer is preferably from 5 to 30 μm, more preferably from 10 to 25 μm, from the viewpoint of coexistence of flame retardancy and adhesion.

In the present invention, the "thickness of each side of the adhesive layer" means the thickness of each of the adhesive layers provided on one or both sides of the substrate (Fig. 1 (a) to (c). Each of Z1 and Z2).

[Peeling sheet]

The adhesive sheet of the present invention can also be adhered, for example, as shown in FIG. 1(b). A release sheet is laminated on the layer of the agent.

The release sheet used in the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and from the viewpoint of ease of handling, a release sheet coated with a release agent on a sheet substrate is preferred. The release sheet may be a release treatment in which a release agent is applied to both surfaces of the sheet substrate, or may be a release treatment in which a release agent is applied to only one side of the sheet substrate.

Examples of the sheet base material used for the release sheet include a paper base material such as cellophane, coated paper, and cast coated paper; and a laminated paper in which a thermoplastic resin such as polyethylene is laminated on the paper base material; or A polyester film such as ethylene terephthalate, polybutylene terephthalate or polyethylene naphthalate; a plastic film such as a polyolefin film such as polypropylene or polyethylene.

Examples of the release agent include a rubber-based elastomer such as an olefin resin, an isoprene resin, and a butadiene resin, a long-chain alkyl resin, an alkyd resin, a fluorine resin, and a polyoxyl Resin or the like.

The thickness of the release sheet is not particularly limited and is usually 20 to 200 μm, preferably 25 to 150 μm.

The thickness of the layer formed of the release agent in the release sheet is not particularly limited. However, when the release agent is applied in a solution state, it is preferably 0.01 to 2.0 μm, more preferably 0.03 to 1.0 μm. When a plastic film is used as the sheet substrate of the release sheet, the thickness of the plastic film is preferably from 3 to 50 μm, more preferably from 5 to 40 μm.

[Method of manufacturing adhesive sheet]

The method for producing the adhesive sheet of the present invention is not particularly limited.

As a method of manufacturing the adhesive sheet 1a shown in Fig. 1(a), The adhesive composition of the present invention is applied onto the substrate 11 and a method for producing the adhesive layer 12a by drying, or the adhesive composition of the present invention is applied onto the release sheet 13a and dried to form an adhesive layer 12a. The adhesive layer 12a and the substrate 11 are bonded together, and after the adhesive sheet 1b is obtained, the release sheet is removed and manufactured.

Moreover, as a method of manufacturing the adhesive sheet 1b shown in Fig. 1(b), a method of manufacturing the release sheet 13a on the adhesive layer 12a after the production of the above-mentioned pressure-sensitive adhesive sheet 1a, or a release sheet 13a may be mentioned. The adhesive composition of the present invention is coated with a method of drying the adhesive layer 12a, bonding the adhesive layer 12a and the substrate 11, and the like.

As a method of producing the adhesive sheet 1c shown in Fig. 1(c), the adhesive composition of the present invention is applied to one surface of the substrate 11 and dried to form the adhesive layer 12a. On the other surface of the material 11, the method of manufacturing the adhesive layer 12b is similarly formed, or two sheets of the adhesive layer are provided on the release sheet, and the adhesive layer and the substrate of the sheet are bonded, and once the adhesive sheet 1b is obtained Thereafter, the method of removing the release sheet and the like is carried out.

When the adhesive composition is applied, in order to easily form a thin adhesive layer on the substrate, it is preferred to dilute the adhesive composition with a solvent to prepare a coating liquid having an appropriate solid concentration, and apply the coating.

The solvent to be used may, for example, be an organic solvent such as toluene, ethyl acetate or methyl ethyl ketone. The thinned adhesive layer can be formed by blending these organic solvents into an adhesive solution having a moderate solid concentration. The solid content of the adhesive solution is preferably from 5 to 60% by mass, more preferably from 10 to 40% by mass. If it is 5% by mass or more, it is used for coating. When the viscosity is 60% by mass or less, the adhesive solution has an appropriate viscosity, and workability is good when the adhesive solution is applied.

The method of forming the adhesive layer on the substrate or on the release sheet is not particularly limited, and examples thereof include a method of forming a coating liquid in which the organic solvent is blended by a well-known coating method.

Examples of the coating method include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a roll coating method, a blade coating method, a die coating method, and a gravure method. A well-known method such as a coating method.

Further, in order to prevent the solvent or the low-boiling component from remaining, and in the case where the crosslinking agent has been blended, in order to carry out the crosslinking (reaction), the adhesion is exhibited, and after application to the substrate or the release sheet, it is preferably carried out. Heat treatment.

[The physical properties of the adhesive sheet]

The adhesive sheet of the present invention produced as described above is in the measurement method described in the following examples, and the adhesive force at normal temperature (23° C., 50% RH (relative humidity)) is 8 N/25 mm or more, and high temperature (80° C.). When the adhesion is 8N/25mm or more and the flame retardancy is VTM-0 according to the UL94 specification, it can fully satisfy the room temperature adhesion, high temperature (80 °C) adhesion and flame retardancy.

[Examples]

The invention is described in more detail by way of examples, but the invention is not limited by the examples.

The weight average molecular weight (Mw) shown in the following examples was measured using the standard polystyrene conversion under the following conditions using "HLC-8020" manufactured by Tosoh Corporation.

(measurement conditions)

Column: "TSK gel GMHXL (×2)" "TSK gel G2000HXL" (made by Tosoh Co., Ltd.)

Column temperature: 40 ° C

Developing solvent: tetrahydrofuran

Flow rate: 1.0 mL/min

Detector: differential refractometer

Further, the room temperature adhesion test of the adhesive sheet obtained in the examples, the adhesion test at high temperature (80 ° C), the mass retention rate, and the evaluation of the flame retardancy were carried out by the methods shown below.

(1) Normal temperature adhesion test

In addition to the polyester film which is coated with polyimine on both surfaces (manufactured by Toray Industries, Inc., trade name "Lumirror ZV10 #25", thickness: 25 μm), the following examples and comparative examples were used. In the same way, an adhesive sheet for the adhesion test was produced.

The release sheet was peeled off, and a test piece of the above-mentioned adhesive sheet cut into 25 mm × 300 mm was placed in a 23 ° C, 50% RH environment, and a rubber roller having a weight of 2 kg was used for the attached body (SUS304 steel plate #360). The test piece was attached as a sample for the adhesion test. After 24 hours of attachment, the adhesion was measured by a peeling method under the conditions of a peeling angle of 180° and a peeling speed of 300 mm/min.

(2) Adhesion test at high temperature (80 ° C)

The same adhesive sheet as used in the room temperature adhesion test of the above (1) was used in the test.

The release sheet was peeled off, and the test piece of the above-mentioned adhesive sheet cut into 25 mm × 300 mm was cut in a 23 ° C, 50% RH environment. (SUS304 steel plate #360), a rubber roller having a weight of 2 kg was used for one round trip, and a test piece was attached as a sample for adhesion test. After attaching for 24 hours, after leaving to stand in an environment of 80 ° C for 60 minutes, the adhesion was measured by a peeling method under the conditions of a peeling angle of 180° and a peeling speed of 300 mm/min under the same environment.

(3) Quality retention rate

In place of the base material, a release sheet (manufactured by LINTEC Co., Ltd., trade name "SP-PET381031", a polyester film coated with a polyfluorene oxide on a release-treated surface, and a thickness of 38 μm) was used, and was produced in the same manner as in the examples and the comparative examples. An adhesive sheet for a quality retention test in which the flame-retardant adhesive layer is sandwiched between two release sheets.

The adhesive sheet was cut into a predetermined size, and two peeling sheets were peeled off and used as a sample for measurement, and the initial mass was measured. Then, using a thermal analyzer (manufactured by Shimadzu Corporation, trade name "DTG-60"), the sample for measurement was heated under a nitrogen atmosphere (nitrogen flow rate of 100 ml/min) and a temperature increase rate of 20 ° C/min. The heating was completed up to 600 ° C, and the remaining mass was measured.

Then, the mass retention ratio (%) was obtained from the following formula.

Quality retention rate (%) = (residual quality / initial quality) × 100

(4) Flame retardancy evaluation

The release sheet of the flame-retardant adhesive sheet produced was peeled off, and the test specified in the vertical flame test method for the thin material of UL94, which is issued by the insurance laboratory company, was conducted to determine the VTM level. The sample size of the flame-retardant adhesive sheet used for the evaluation was 50 mm × 200 mm, and the test was performed with the adhesive layer being the outer side.

Furthermore, the criterion for determining the VTM level is as follows.

VTM-0: The burning time of the sample is within 10 seconds, and the burning of the absorbent cotton is not caused by the burning or falling objects, and the burning of the marking line (125 mm from the lower end of the sample) is not seen.

VTM-1: The burning time of the sample is within 30 seconds, and the cotton wool does not catch fire due to burning or falling objects, and the burning to the marking line is not seen.

VTM-2: The burning time of the sample was within 30 seconds, and no burning was observed until the marking.

In addition, in Table 2, those who meet VTM-0 will be regarded as "VTM-0", those who do not comply with VTM-0 but who comply with VTM-1 will be regarded as "VTM-1", and will not comply with VTM-0 and VTM- 1 However, those who meet VTM-2 will be regarded as “VTM-2”, and those who do not meet VTM-0 and VTM-1 and VTM-2 will be regarded as “failed”.

Manufacturing example 1

(Modulation of Acrylic Copolymer Solution 1)

90 parts by mass of butyl acrylate and 10 parts by mass of acrylic acid as a monomer component, 200 parts by mass of ethyl acetate as a solvent, and 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator were charged into the reactor. And mix. After degassing under nitrogen for 4 hours, the temperature was gradually raised to 60 ° C, and polymerization was carried out while stirring for 24 hours to obtain an ethyl acetate solution containing an acrylic copolymer 1 having a weight average molecular weight of 650,000 (solid content concentration 33 mass). %).

Manufacturing Example 2

(Modulation of Acrylic Copolymer Solution 2)

In addition to using 80 parts by mass of butyl acrylate and 20 parts by mass of propylene The polymerization reaction was carried out in the same manner as in Production Example 1 except that the acid was used as the monomer component, and an ethyl acetate solution (solid content concentration: 33% by mass) containing the acrylic copolymer 2 having a weight average molecular weight of 600,000 was obtained.

Manufacturing Example 3

(Modulation of Acrylic Copolymer Solution 3)

A polymerization reaction was carried out in the same manner as in Production Example 1 except that 95 parts by mass of butyl acrylate and 5 parts by mass of acrylic acid were used as the monomer component, thereby obtaining an ethyl acetate solution containing the acrylic copolymer 3 having a weight average molecular weight of 600,000. (solid content concentration: 33% by mass).

Manufacturing Example 4

(Modulation of Acrylic Copolymer Solution 4)

A polymerization reaction was carried out in the same manner as in Production Example 1 except that 48 parts by mass of butyl acrylate, 48 parts by mass of 2-ethylhexyl acrylate, and 4 parts by mass of acrylic acid were used as the monomer component, and a weight average molecular weight of 60 was obtained. An ethyl acetate solution (solid content concentration: 33% by mass) of an acrylic copolymer 4.

Example 1

(Production of flame retardant adhesive sheet)

100 parts by mass (solid content) of the ethyl acetate solution containing the acrylic copolymer 1 obtained in Production Example 1 and 2.3 parts by mass (solid content) were diluted with ethyl acetate to have a solid content of 10% by mass. Isocyanate-based crosslinking agent (manufactured by Japan Polyurethane Co., Ltd., trade name "Coronate L", ethyl acetate solution of trimethylolpropane-modified toluene diisocyanate (solid content: 75 mass%) ), with 30 parts by mass of nitrogen-containing phosphate-based flame retardant (ADEKA Co., Ltd.) A mixture of the product name "Adekastab FP-2200" was prepared to prepare a solution of the adhesive composition.

This solution was applied to a polyfluorene-treated 38 μm polyester film (manufactured by LINTEC Co., Ltd., trade name "SP-PET381031"), and the thickness of the dried adhesive layer was 20 μm at 100 After drying at °C for 1 minute, it was transferred to a substrate and a polyester film coated with a polyimide resin on both sides (manufactured by Toray Industries, Inc., trade name "Lumirror ZV30#40", thickness: 47 μm, in accordance with UL94 specifications The test VTM-0) specified in the test was air-dried at 23 ° C and 50% RH for 7 days to produce a flame retardant adhesive sheet.

In addition, the thickness and the total thickness of each layer of the flame-retardant adhesive sheet were measured by observing the cross section of the sheet with an electron microscope (manufactured by KEYENCE Co., Ltd., trade name "VHX-1000").

Examples 2 to 5 and Comparative Examples 1 to 6

An adhesive sheet was produced in the same manner as in Example 1 except that the composition of the adhesive was changed to the one shown in Table 1.

The details of the main agent, flame retardant, and crosslinking agent in Table 1 are as follows.

BA: butyl acrylate

2EHA: 2-ethylhexyl acrylate

AAc: Acrylic

FP2200: Adekastab FP2200 (manufactured by ADEKA Co., Ltd., a phosphate-containing flame retardant)

TBP: Tributyl phosphate (manufactured by Daiba Chemical Industry Co., Ltd.) Coronate L: isocyanate-based crosslinking agent (manufactured by Japan Polyurethane Co., Ltd., trade name "Coronate L", trimethylolpropane modified Acetate solution of toluene diisocyanate (solid content: 75 mass%))

Table 2 shows the room temperature adhesion of the flame-retardant adhesive sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 6 (test 1), the adhesion at high temperature (80 ° C) (test 2), and the mass retention rate (test 3). And the results of the flame retardancy evaluation (UL94 vertical flammability, test 4).

[Industrial availability]

The flame-retardant adhesive composition of the present invention is flame-retardant without adding a halogen compound, and maintains adhesive properties even at a high temperature, and it is easy to prepare a homogeneous coating liquid using a flame-retardant adhesive composition. The flame retardant adhesive composition of the fuel can provide a flame retardant adhesive sheet having excellent flame retardancy and adhesion at room temperature and adhesion at high temperature (80 ° C) by using the adhesive composition.

1a, 1b, 1c‧‧‧ flame retardant adhesive sheets

11‧‧‧Substrate

12a, 12b‧‧‧Adhesive layer

13a‧‧‧ peeling film

Claims (6)

A flame retardant adhesive composition characterized by comprising (A) a (meth) acrylate polymer and (B) a nitrogen-containing phosphate-based flame retardant, relative to 100 parts by mass of (A) (A) (meth) acrylate polymer, (B) nitrogen-containing phosphate-based flame retardant content of 20 to 50 parts by mass, and meet the following requirements (1) and (2): (1) (A) (methyl The acrylate polymer contains 70 to 93% by mass of (a) an alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms, and 7 to 30% by mass of (b) a vinyl group having a carboxyl group in the molecule. The compound is used as a monomer component during polymerization; (2) In the thermogravimetric measurement under a nitrogen atmosphere, the mass retention of the flame retardant adhesive composition at 600 ° C is 20% or more. The flame retardant adhesive composition of claim 1, which further comprises (C) a crosslinking agent. A flame retardant adhesive composition according to claim 1 or 2, wherein (B) the flame retardant is an ammonium phosphate-based flame retardant. A flame-retardant adhesive sheet characterized in that an adhesive layer of the flame-retardant adhesive composition according to any one of claims 1 to 3 is laminated on at least one side of the substrate. The flame-retardant adhesive sheet of claim 4, wherein the thickness of the adhesive layer is 5 to 30 μm. A flame-retardant adhesive sheet according to claim 4 or 5, wherein the substrate has a flame retardancy in accordance with the test VTM-0 specified in the UL94 specification.