JP2021024869A - Adhesive sheet - Google Patents

Abstract

To provide an adhesive sheet that has heat resistance to withstand a solder reflow process, has excellent re-peelability, and is transparent, at low cost.SOLUTION: A adhesive sheet at least has an adhesive layer and a support layer. The support layer is composed of nonwoven fabric and a binder. The nonwoven fabric at least contains a glass fiber. The binder is composed of an organic component and an inorganic component, and the content of the inorganic component in the binder is 10-50 vol.%. The binder preferably contains an antioxidant.SELECTED DRAWING: None

Description

The present invention relates to an adhesive sheet, and more particularly to an adhesive sheet that can be used as a process film having removability used in the production of electronic industrial materials such as printed wiring boards.

The printed wiring board is a wiring board in which the circuit pattern of the conductor required for connecting the electric / electronic components mounted on the printed wiring board is formed on the surface or surface of the insulating substrate and the inside thereof by printing or the like. Such a printed wiring board can be roughly classified into a rigid printed wiring board and a flexible printed wiring board from the viewpoint of shape, and structurally, it is divided into a single layer and two or more layers. Among these printed wiring boards, the flexible printed wiring board is a flexible printed wiring board in which a circuit pattern of a conductor is formed on a highly flexible insulating base sheet, and is contained in a space having a narrow and complicated structure inside an electronic device. It is an indispensable substrate for three-dimensional high-density mounting in. Such flexible printed wiring boards are one of the most promising electronic device components that can meet the demands of recent years for smaller size, lighter weight, higher density, and higher accuracy, and their demand is rapidly increasing. It's growing.

Since flexibility is required in the flexible printed wiring board, a plastic sheet as an insulating base sheet, particularly a plastic sheet having excellent heat resistance and insulating properties such as a polyimide sheet and a polyphenylene sulfide sheet, is used. It is used, and a circuit pattern is formed on the surface or the surface of the base material sheet and the inside thereof by a metal material such as copper. As a method for forming a circuit pattern, for example, an additive method is known as well as a constructive method in which only a necessary portion of a copper foil of a copper-clad laminate is left and the other portion is dissolved and removed by an etching process. This additive method is a method in which a circuit pattern is formed by plating only a necessary part of a substrate, and there are a semi-additive method and a full additive method. The performance required for such a flexible printed wiring board includes, for example, dimensional accuracy, low warpage / twist rate, heat resistance, peeling strength, bending strength, high volume resistivity, chemical resistance, and heat bending strength. In addition to the above, the processing suitability of the printed wiring board is also important.

In such a flexible printed wiring board, in the process of forming the above-mentioned circuit and mounting the electric / electronic components, in order to suppress solvent contamination, foreign matter contamination, generation of defects, etc. on the wiring board, those treatments are generally performed. A process film having removability (hereinafter, referred to as “removable process film”) is attached to the base material sheet to be used in advance. This re-peeling step film is provided with an adhesive layer that can be re-peeled on one surface of the base film, and is attached to a base sheet for a flexible printed wiring board, and then punched and subjected to a solvent. After undergoing various steps such as immersion in a film and hot pressing, the film is peeled off from the produced flexible printed wiring board. Therefore, in addition to not causing floating or peeling during the process, there is no adhesive residue on the adherend (base sheet) after peeling, and the adherend does not curl. It is important to have peelability.

Further, in recent years, in the component mounting process on a flexible printed wiring board, a method of collectively connecting and mounting by putting the component and the board into a solder reflow furnace in a aligned state has been widely adopted. In this case, since operations in a high temperature region such as soldering are included, heat resistance is required for the base material and the adhesive layer of the re-peeling step film. Currently, when a solder reflow furnace having a temperature of about 200 ° C. or higher is used, it is the mainstream to use a polyimide film having high heat resistance as a base material for the re-peeling step film (for example, Patent Document 1). Alternatively, a method using a polyetheretherketone film as a base material has also been proposed (for example, Patent Document 2).

An organic-inorganic composite sheet obtained by impregnating glass fibers with a curable resin and curing it is known as a so-called "Galaepo substrate" and is widely used as a base material for various hard printed wiring boards. It has also been proposed that such an organic-inorganic composite sheet can be used as a base material for an adhesive sheet (for example, Patent Document 3).

Adhesive sheets based on a cloth containing glass fibers are known to be used as a base material when heat resistance and durability are required (for example, Patent Documents 4 and 5). It has also been proposed that an adhesive layer is provided on a base material obtained by impregnating a polyester non-woven fabric with a resin and used as an adhesive sheet (for example, Patent Document 6).

Japanese Unexamined Patent Publication No. 2010-116532 Japanese Unexamined Patent Publication No. 2013-159616 Japanese Unexamined Patent Publication No. 2014-234500 Japanese Unexamined Patent Publication No. 2014-9318 Japanese Unexamined Patent Publication No. 2003-261835 Japanese Unexamined Patent Publication No. 2010-76261

The film-like base materials of various super engineering plastics such as the polyimide film and polyetheretherketone film described in Patent Document 1 or Patent Document 2 have high heat resistance and have sufficient heat resistance even in the solder reflow process. However, the price is high, and there is a problem that the process cost becomes high, especially when it is used for a re-peeling process film which is supposed to be discarded after a short period of use. Further, Patent Document 1 also proposes that a metal material is used as a base material, but the metal material is not transparent, and the state of the mounted parts and the like cannot be confirmed with the re-peeling process film attached. ..

A method of impregnating a glass fiber cloth with a curable resin, particularly an epoxy resin, has been known for a long time, but the epoxy resin has poor reactivity, and it is necessary to pressurize the resin impregnation at a high temperature after making a prepreg once. , Has the drawback of poor productivity.

Since the non-woven fabric can be made into a sheet as it is, it is not necessary to spin the fiber as in the case of woven fabric or knitted fabric. Therefore, the cost can be lower than that of woven fabrics and knitted fabrics, but on the other hand, it has the disadvantage of being less durable than woven fabrics and knitted fabrics. In Patent Documents 4 and 5, a cloth made of glass fiber is used, and in particular, in Patent Document 4, a material bonded with a metal foil and an adhesive is used as a base material, and no consideration is given to problems peculiar to non-woven fabric. Absent. Further, in these documents, the general use of the pressure-sensitive adhesive sheet is assumed, and no problem is considered in order to obtain a re-peeling process film that can withstand the solder reflow process.

Patent Document 6 proposes a method for using a polyester non-woven fabric as an adhesive sheet. However, the heat resistance of polyester is less than 200 ° C., and it is not assumed to be used in a high temperature environment such as a solder reflow process, and it does not solve the problem of a re-peeling process film that can withstand the solder reflow process.

Therefore, an object of the present invention is to provide an adhesive sheet having heat resistance that can withstand a solder reflow process, excellent removability, and transparency at low cost.

As a result of diligent studies to solve the above problems, the present inventor has found that the problem can be solved by an adhesive sheet having the following configuration.

1. 1. It has at least an adhesive layer and a support layer, the support layer is composed of a non-woven fabric and a binder, the non-woven fabric contains at least glass fibers, the binder is composed of an organic component and an inorganic component, and the ratio of the inorganic component in the binder is An adhesive sheet in the range of 10 to 50% by volume.
2. 2. The pressure-sensitive adhesive sheet according to 1, wherein the binder contains an antioxidant.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an adhesive sheet having heat resistance that can withstand solder reflow, excellent removability, and transparency at low cost.

The pressure-sensitive adhesive sheet of the present invention has at least a pressure-sensitive adhesive layer and a support layer.

<Adhesive layer>
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention can contain known pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, and silicone pressure-sensitive adhesives. Among these, acrylic pressure-sensitive adhesives and urethane pressure-sensitive adhesives that do not generate siloxane gas are preferable, and in order to have heat resistance that can withstand the solder reflow process, the 5% weight loss temperature of the dried product must be 200 ° C. or higher. , More preferably 250 ° C. or higher, and in this respect, an acrylic pressure-sensitive adhesive having high heat resistance is preferable. The 5% weight loss temperature of the dried product can be measured by a thermogravimetric differential thermal analyzer (TG-DTA).

As the acrylic pressure-sensitive adhesive preferably used for the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention, an acrylic copolymer obtained by polymerizing a plurality of monomer components including an acrylic monomer can be used. Examples of the monomer component that can be used including the acrylic monomer include carboxyl group-containing monomers such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, or anhydrides thereof (for example, maleic anhydride and the like). ), Methyl (meth) acrylate, Ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, s (meth) acrylate -Butyl, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, (meth) 2-Ethylhexyl acrylate, Isooctyl (meth) acrylate, Nonyl (meth) acrylate, Isononyl (meth) acrylate, decyl (meth) acrylate, Isodecyl (meth) acrylate, Undecyl (meth) acrylate, (meth) ) Dodecyl acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, (meth) (Meta) acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms, such as isostearyl acrylate, nonadecil (meth) acrylate, and eicosyl (meth) acrylate, (meth) acrylic. 2-methoxyethyl acid, 2-ethoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, (meth) acrylic (Meta) acrylic acid alkoxyalkyl ester such as 4-methoxybutyl acid, 4-ethoxybutyl (meth) acrylic acid, 2-hydroxyethyl (meth) acrylic acid, 3-hydroxypropyl (meth) acrylic acid, (meth) acrylic Hydroxyalkyl (meth) acrylate such as 4-hydroxybutyl acid, 6-hydroxyhexyl (meth) acrylate, hydroxyl group (hydroxyl) -containing monomer such as allyl alcohol, (meth) acrylamide, N, N-dimethyl (meth) Acrylic, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-hydroxy Amid group-containing monomers such as ethyl acrylamide, amino group-containing monomers such as (meth) aminoethyl acrylate, dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, Glycidyl group-containing monomers such as methylglycidyl (meth) acrylate, cyano group-containing monomers such as acrylonitrile and methacrylonitrile, N-vinyl-2-pyrrolidone, (meth) acryloylmorpholin, N-vinylpyridine, N-vinylpiperidone , N-vinylpyrimidine, N-vinylpiperazin, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole and other heterocyclic monomer, sulfonic acid group-containing monomer such as sodium vinylsulfonate, 2-hydroxyethyl Examples thereof include a phosphate group-containing monomer such as acryloyl phosphate, an imide group-containing monomer such as cyclohexyl maleimide and isopropyl maleimide, and an isocyanate group-containing monomer such as 2-methacryloyloxyethyl isocyanate.

The acrylic pressure-sensitive adhesive used in the present invention may also contain a thermoplastic resin. Thermoplastic resins include polyamide, polyurethane resin, polyvinyl acetate, polyvinyl acetal, polystyrene, fluororesin, polycarbonate, polyether, polyisobutylene, petroleum resin, rosin, nitrocellulose, sucrose ester, vinyl chloride / vinyl acetate copolymer. Examples thereof include coalescence, ethylene / vinyl acetate-based copolymer, α-olefin / maleic anhydride-based copolymer, styrene / maleic anhydride-based copolymer, and the like. The thermoplastic resin is preferably used in the range of 10 to 80% by mass with respect to the acrylic copolymer.

The acrylic pressure-sensitive adhesive used in the present invention may contain a pressure-sensitive adhesive. Examples of the tackifier include rosin esters obtained by esterifying unmodified rosin of gum rosin, tall oil rosin, and wood rosin with alcohol, and modified rosins such as disproportionated rosin modified from unmodified rosin, polymerized rosin, and hydrogenated rosin. Disproportionate rosin ester obtained by further esterifying these modified rosins with alcohol or the like, polymerized rosin ester, modified rosin ester such as hydrogenated rosin ester, rosin phenol obtained by adding phenol to unmodified rosin, terpenephenol resin, dipentene resin, aromatic Examples thereof include group-modified terpene resin, hydrogenated terpene resin, acid-modified terpene resin, terpene-based resin such as styrene terpene resin, and petroleum resin. The tackifier may be used alone or in combination of two or more, and it is particularly preferable to use a rosin-based tackifier and a terpene-based tackifier in combination. The amount of the tackifier is preferably used in the range of 5 to 100% by mass with respect to the acrylic copolymer.

Examples of commercially available products of the acrylic pressure-sensitive adhesive described above include Oliveine (registered trademark) BPS6430OP, Oliveine BPS5978, Oliveine BPS5227-1 manufactured by Toyochem Co., Ltd.

In the present invention, in order to further improve the cohesive force of the acrylic pressure-sensitive adhesive and obtain stable thermal conductivity, it is preferable that the heat conductive layer contains a cross-linking agent together with the acrylic pressure-sensitive adhesive. As the cross-linking agent, an isocyanate cross-linking agent, an epoxy cross-linking agent, a metal chelate cross-linking agent, an aziridine cross-linking agent and the like can be used. Of these, it is preferable to use an isocyanate cross-linking agent or an aziridine cross-linking agent.

In the present invention, the adhesive layer preferably contains an antioxidant. Examples of the antioxidant include radical chain inhibitors such as phenolic antioxidants and amine-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants and the like. Among these, phenol-based antioxidants and amine-based antioxidants are preferable.

The phenolic antioxidants are, for example, 2,6-di-t-butyl-p-cresol, butylated hydroxyanisol, 2,6-di-t-butyl-4-ethylphenol, and stea-β- (3). , 5-Di-t-butyl-4-hydroxyphenyl) propionate and other monophenolic antioxidants, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4) -Ethyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl-6-t-butylphenol), and 3,9 -Bis [1,1-dimethyl-2- [β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxaspiro [5,5 ] Bisphenol antioxidants such as undecane, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [ 3,3'-bis- (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, and 1,3,5-tris (3', 5'-di-t-butyl-4) Examples thereof include high molecular weight phenolic antioxidants such as ′ -hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione and tocophenol.

Examples of amine-based antioxidants include N-phenyl-1-naphthylamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, p, p'-dioctyldiphenylamine, phenyl-α-naphthylamine, and 6-ethoxy-. Examples thereof include aromatic amine-based antioxidants such as 1,2-dihydro-2,2,4-trimethylquinolin and phenothiazine.

Examples of the sulfur-based antioxidant include dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearyl 3,3'-thiodipropionate.

Examples of the phosphorus-based antioxidant include triphenylphosphine, diphenylisodecylphosphine, phenyldiisodecylphosphine and the like.

The antioxidant may be used alone or in combination of two or more. The amount of the antioxidant used is preferably in the range of 0.1 to 10% by mass of the total amount of the acrylic copolymer, the thermoplastic resin, and the tackifier.

As the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention, known substances such as plasticizers, matting agents, surfactants, metal soaps, and flame retardants can be further used.

The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention is preferably 5 to 100 μm, more preferably 10 to 50 μm.

<Support layer>
The support layer of the pressure-sensitive adhesive sheet of the present invention comprises a non-woven fabric containing at least glass fibers and a binder. Further, the binder is composed of an organic component and an inorganic component, and the ratio of the inorganic component in the binder is in the range of 10 to 50% by volume.

As the non-woven fabric having the support layer, a non-woven fabric produced by a known method can be used. As the glass fiber contained in the non-woven fabric, known glass fibers such as E glass, C glass, S glass, D glass, ECR glass, and AR glass can be used. The fiber diameter is not particularly limited, but from the viewpoint of cost, those having a fiber diameter of 4 to 18 μm, particularly preferably 6 to 13 μm. Further, organic fibers may be added if necessary. For example, para-aramid fiber, meta-aramid fiber, liquid crystal polyester fiber, Teflon (registered trademark) fiber, polyimide fiber, polyparaphenylene sulfide fiber and the like can be used. The fiber used for the non-woven fabric is most preferably 100% by mass of glass fiber, preferably at least 50% by mass or more, and more preferably 90% by mass or more.

An adhesive can also be used for the non-woven fabric to bond the fibers to each other. As the adhesive, a known resin-based adhesive can be used. For example, a one-component adhesive, a two-component adhesive, a thermosetting adhesive, a hot melt type adhesive, and an ultraviolet curable Examples include mold adhesives and electron beam curable adhesives. Specifically, one kind or a mixture of two or more kinds selected from urethane-based resin, vinyl acetate-based resin, styrene-butadiene copolymer-based, acrylic-based resin, vinyl chloride-based resin and epoxy-based resin is exemplified.

The thickness of the non-woven fabric contained in the support layer is preferably 10 to 200 μm, more preferably 20 to 150 μm. The basis weight is ^{2 to} 500 g / m 2, preferably 5 to 200 g / m ² .

The binder contained in the support layer is composed of an inorganic component and an organic component. As the inorganic component, inorganic particles composed of known inorganic components such as silica, zirconia, aluminum hydroxide, magnesium hydroxide, zeolite, aluminum oxide, magnesium oxide, zinc oxide, titanium oxide, cerium oxide, talc, calcium carbonate, magnesium carbonate and the like. Can be used. The particle size (median diameter) is preferably 200 μm or less, more preferably 100 μm or less in order to maintain transparency. Further, it is preferable that the surface of the inorganic particles is surface-treated with a silane coupling agent or the like. As a commercially available product of such inorganic particles, an organosilica sol manufactured by Nissan Chemical Industries, Ltd., for example, MEK-AC-2140Z, MEK-AC-4130Y, MEK-AC-5140Z and the like can be mentioned as preferable examples.

Further, as an inorganic component of the binder contained in the support layer, a so-called matting agent having a particle size of more than 200 μm can be used in combination. However, the amount of the matting agent used is preferably 10% by volume or less, and more preferably 5% by volume or less of the inorganic component in order to maintain transparency.

As the organic component of the binder contained in the support layer, known resins such as polyimide resin, polyamideimide resin, polyamide resin, epoxy resin, silicone resin, acrylic resin and urethane resin can be used, but the acrylic pressure-sensitive adhesive used in the pressure-sensitive adhesive layer. Is preferable because it improves the adhesion between the adhesive layer and the support layer, the thermal expansion rate, and the like.

It is preferable that the binder contained in the support layer of the pressure-sensitive adhesive sheet of the present invention contains an antioxidant. As the antioxidant, the same ones used for the adhesive layer can be used, and among them, phenolic antioxidants and amine-based antioxidants are preferable. The antioxidant is preferably contained in an amount of 0.1 to 10% by mass, more preferably 0.5 to 7.5% by mass, of the organic component of the binder, although it depends on the type of the antioxidant used. .. Further, the binder can contain known substances such as plasticizers, surfactants, metal soaps, flame retardants, antifoaming agents and antistatic agents.

As described above, the inorganic component of the binder contained in the support layer is contained in an amount of 10 to 50% by volume, preferably 20 to 40% by volume, based on the entire binder. The thickness of the support layer is preferably 20 to 250 μm, more preferably 40 to 150 μm.

<Adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention preferably comprises a pressure-sensitive adhesive layer coating liquid containing the above-mentioned components and diluted with an organic solvent, which is laminated on a release film, applied, dried, and then a non-woven fabric is bonded to the non-woven fabric. It can be easily produced by applying a binder coating solution containing the above-mentioned components and diluted with an organic solvent to the other surface and drying the mixture. Examples of the release film include polyethylene terephthalate (PET) film, polypropylene (PP) film, polyethylene (PE) film, and the like, or a release film obtained by applying a known release agent such as a silicone release agent on the surface thereof. ..

In addition to the adhesive layer and the support layer, the adhesive sheet of the present invention may be provided with known layers such as an antistatic layer, a hard coat layer, and a release layer.

Hereinafter, the present invention will be described in more detail with reference to Examples, and the present invention will be specifically described, but the present invention is not limited to the following Examples. In addition, in calculating the content volume of each component, the following values were used for the density of each component. Silica: 2.2 g / cm ³ , acrylic adhesive (combined with aziridine cross-linking agent): 1.19 g / cm ³ , Nocrack (registered trademark) CD: 1.1 g / cm ³ .

"5% weight loss temperature measurement of adhesive"
The following physical property measurement coating solution was prepared and coated on a release film (RF-CS001 manufactured by Aim Co., Ltd., thickness 75 μm) so as to have a dry film thickness of 30 μm. After the obtained adhesive film was attached to an aluminum pan and the release film was peeled off, it was considered to be a dried product at 130 ° C. (all residual solvent was evaporated) by a DTG-60 thermogravimetric differential thermal analyzer manufactured by Shimadzu Corporation. The 5% weight loss temperature with respect to the state of) was measured and found to be 256 ° C. Therefore, the pressure-sensitive adhesive sheet using the acrylic pressure-sensitive adhesive contained in the following physical property measurement coating liquid has heat resistance that can withstand the solder reflow process.

<Physical characteristic measurement coating solution>
Oliveine BPS5978 (Acrylic adhesive manufactured by Toyochem Co., Ltd. Solid content 35% by mass)
100g
Oliveine BXX5134 (Aziridine cross-linking agent manufactured by Toyochem Co., Ltd. Solid content 5% by mass)
9g
Ethyl acetate was added to bring the total amount to 350 g.

"Preparation of adhesive sheet 1"
The following adhesive coating solution 1 was prepared and coated on a release film (RF-CS001 manufactured by Aim Co., Ltd.) so as to have a dry film thickness of 30 μm. Subsequently, a non-woven fabric (basis weight 30 g / m ² , thickness 150 μm) made of glass fiber having a fiber content of 100% by mass was bonded to prepare a glass fiber non-woven fabric 1 coated with an adhesive layer.

<Adhesive coating liquid 1>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD (Amine-based antioxidant manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. Solid content 100% by mass)
1.75g
Ethyl acetate was added to bring the total amount to 350 g.

A binder coating solution 1 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 1. The weight increase due to the application and drying of the binder coating solution 1 was 197.5 g / m ² . The thickness of the pressure-sensitive adhesive sheet 1 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 32.6% by volume.

<Binder coating liquid 1>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD 1.75g
Organo silica sol MEK-AC-5140Z (Nissan Chemical Industries, Ltd. silica sol. Particle size (median diameter) 80 μm. Solid content 40% by mass) 83.3 g
Ethyl acetate was added to bring the total amount to 350 g.

"Preparation of adhesive sheet 2"
A binder coating solution 2 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 2. The weight increase due to the application and drying of the binder coating solution 2 was 161.9 g / m ² . The thickness of the pressure-sensitive adhesive sheet 2 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 5.5% by volume.

<Binder coating liquid 2>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD 1.75g
Organo Silica Sol MEK-AC-5140Z 10g
Ethyl acetate was added to bring the total amount to 350 g.

"Preparation of adhesive sheet 3"
A binder coating solution 3 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 3. The weight increase due to the application and drying of the binder coating solution 3 was 174.1 g / m ² . The thickness of the pressure-sensitive adhesive sheet 3 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 14.8% by volume.

<Binder coating liquid 3>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD 1.75g
Organo Silica Sol MEK-AC-5140Z 30g
Ethyl acetate was added to bring the total amount to 350 g.

"Preparation of adhesive sheet 4"
A binder coating solution 4 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 4. The weight increase due to the application and drying of the binder coating solution 4 was 188.6 g / m ² . The thickness of the pressure-sensitive adhesive sheet 4 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 25.8% by volume.

<Binder coating liquid 4>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD 1.75g
Organo Silica Sol MEK-AC-5140Z 60g
Ethyl acetate was added to bring the total amount to 350 g.

"Preparation of adhesive sheet 5"
A binder coating solution 5 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 5. The weight increase due to the application and drying of the binder coating solution 5 was 200.0 g / m ² . The thickness of the pressure-sensitive adhesive sheet 5 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 34.3% by volume.

<Binder coating liquid 5>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD 1.75g
Organo Silica Sol MEK-AC-5140Z 90g
Ethyl acetate was added to bring the total amount to 350 g.

"Preparation of adhesive sheet 6"
A binder coating solution 6 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 6. The weight increase due to the application and drying of the binder coating solution 6 was 213.5 g / m ² . The thickness of the pressure-sensitive adhesive sheet 6 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 44.8% by volume.

<Binder coating liquid 6>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD 1.75g
Organo Silica Sol MEK-AC-5140Z 140g
Ethyl acetate was added to bring the total amount to 350 g.

"Preparation of adhesive sheet 7"
A binder coating solution 7 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 7. The weight increase due to the application and drying of the binder coating solution 7 was 227.5 g / m ² . The thickness of the pressure-sensitive adhesive sheet 7 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 55.5% by volume.

<Binder coating liquid 7>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Nocrack CD 1.75g
Organo Silica Sol MEK-AC-5140Z 215g
Ethyl acetate was added to bring the total amount to 365 g.

"Preparation of adhesive sheet 8"
A binder coating solution 8 having the following formulation was applied to the non-woven fabric surface side of the glass fiber non-woven fabric 1 coated with the adhesive layer and dried to prepare an adhesive sheet 8. The weight increase due to the application and drying of the binder coating solution 8 was 198.9 g / m ² . The thickness of the pressure-sensitive adhesive sheet 8 was 265 μm including the release film. The ratio of the inorganic component of the binder coating solution (to the sum of the organic component excluding the solvent and the inorganic component) was 33.7% by volume.

<Binder coating liquid 8>
Oliveine BPS5978 100g
Oliveine BXX5134 9.0g
Organo Silica Sol MEK-AC-5140Z 83.3g
Ethyl acetate was added to bring the total amount to 350 g.

The unheated adhesive strength immediately after the production of the obtained adhesive sheets 1 to 8, the adhesive strength after heating at 260 ° C. for 20 minutes, the adhesive residue, and the transparency were measured according to the following method. The results are shown in Table 1.

<Evaluation of unheated adhesive strength>
The release film (RF-CS001) of the adhesive sheet was peeled off and attached to an aluminum plate having a thickness of 0.1 mm to prepare an adhesive strength measurement sample. The obtained bonded product was cut to a width of 25 mm. The adhesion strength of the obtained test piece was measured with a peeling machine (combination of a T-shaped peeling method attachment manufactured by Imada Co., Ltd. and a force gauge DST).

<Adhesive strength evaluation after 20 minutes at 260 ° C>
The release film (RF-CS001) of the adhesive sheet was peeled off, attached to an aluminum plate having a thickness of 0.1 mm, left at 260 ° C. for 20 minutes, and then cut to a width of 25 mm. The adhesion strength of the obtained test piece was measured with a peeling machine (combination of a T-shaped peeling method attachment manufactured by Imada Co., Ltd. and a force gauge DST). The closer the adhesive strength after heating is to the adhesive strength without heating, the better the removability.

<Remaining glue>
After 20 minutes at 260 ° C., the aluminum surface of the sample whose adhesive strength was evaluated was observed, and the one with the adhesive layer component was marked with x, and the one without it was marked with ◯.

<Transparency>
The adhesive sheet was placed on the newspaper, and those that could read the characters from the adhesive sheet were marked with ○, and those that could not be read were marked with ×.

Adhesive sheet except that Nocrack 300 (phenolic antioxidant manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., density 1.12 g / cm ³ ) was used instead of Nocrack CD in the binder coating so that the solid content was the same. Adhesive sheets were prepared in the same manner as in 1 to 7 and evaluated in the same manner, and the same results as in adhesive sheets 1 to 7 were obtained.

An adhesive sheet was prepared in the same manner as the adhesive sheet 1 except that the following binder coating solution 9 was used instead of the binder coating solution 1, and the same evaluation was performed. As a result, the same results as those of the adhesive sheet 1 were obtained. However, the transparency was ○ because the characters could be read, but it was harder to read than the adhesive sheet 1 because the support layer was colored brown. Further, since the density of polyamide-imide was 1.42 g / cm ³ , the ratio of the inorganic components in the binder coating solution (relative to the sum of the organic components excluding the solvent and the inorganic components) was 32.6% by volume.

<Binder coating liquid 9>
HPC-6000-26 (Polyamide-imide manufactured by Hitachi Kasei Co., Ltd. Solid content 25.7% by mass)
164.6g
Nocrack CD 1.75g
Organo Silica Sol MEK-AC-5140Z 83.3g
Ethyl acetate was added to bring the total amount to 350 g.

From the above results, the effect of the present invention can be clearly seen. Further, since the support layer of the pressure-sensitive adhesive sheet of the present invention does not use a film-like base material of super engineering plastic such as a polyimide film or a polyetheretherketone film, it can be provided at low cost.

Claims (2)

It has at least an adhesive layer and a support layer, the support layer is composed of a non-woven fabric and a binder, the non-woven fabric contains at least glass fibers, the binder is composed of an organic component and an inorganic component, and the ratio of the inorganic component in the binder is An adhesive sheet in the range of 10 to 50% by volume. The pressure-sensitive adhesive sheet according to claim 1, wherein the binder contains an antioxidant.