TWI506111B - And then peeling off the adhesive composition, adhesive sheet, and electronic parts of the cutting process - Google Patents

Description

Re-peeling adhesive composition, adhesive sheet, and cutting method for electronic parts

The present invention relates to a re-peeling adhesive composition, an adhesive sheet produced using the re-peelable adhesive composition, and a cutting method for an electronic component using the adhesive sheet.

In the field of semiconductors and other fields, the diameter of the wafer is increased (450 mm) and the thickness is reduced (100 μm or less), and the demand for compound semiconductors that require attention during operation such as LEDs is greatly increased.

Moreover, in recent years, the development of electronic components has been miniaturized or refined. For example, in ceramic capacitors, the size of 0603 (0.6 mm × 0.3 mm) or 0402 (0.4 mm × 0.2 mm) is not as small as 1 mm. The high capacity caused by the high buildup of the particles, which is severely more than several hundred layers, becomes remarkable.

With such miniaturization or precision, high precision is required for processing of a ceramic pre-fired sheet (green sheet), such as a ceramic capacitor.

The ceramic capacitor is manufactured, for example, by the following steps.

(1) Steps for printing internal electrodes of green sheets

(2) Lamination step

(3) Pressurization step (pressurization pressing step)

(4) Cutting step

(5) Calcination step

(After repeating the layering step (2) and the pressurizing step (3) a certain number of times, the process proceeds to the cutting step (4))

In such a step, as the required precision, for example, the accuracy of the internal electrode printing in the internal electrode printing step (1) of the green sheet, and the accuracy of the electrode position alignment in the laminating step (2) can be cited. In the pressurization step (3), the position of the green sheet deformed by the pressurization is shifted, the accuracy of the offset of the electrode position is prevented, and the cutting accuracy in the step (4) is cut off. Etc. as an aspect that should be noted especially when manufacturing. Further, if one of the steps is inferior in accuracy, the obtained product becomes a defective product, and the productivity is drastically lowered.

In these steps, the internal electrode printing step (1), the laminating step (2), and the cutting step (4) of the green sheet are required to be improved by the improvement and precision of the device because mechanical precision is required. .

Further, in the cutting step of the step (4), the heat-peelable pressure-sensitive adhesive sheet is widely used in order to improve the cutting accuracy. Thereby, the green sheet is firmly fixed at the time of cutting, but the adhesive force is lost by heating after the cutting step, and the cut ceramic capacitor can be easily peeled off from the sheet.

However, in recent years, in order to improve the cutting accuracy at the time of cutting processing, a method of cutting in a state where the green sheet is softened by heating, in particular, during cutting processing is widely used.

Further, the heat-peelable pressure-sensitive adhesive sheet is required to have a higher green sheet retention property even in a high-temperature environment.

However, the conventional tape has a tendency that the green sheet retainability in a high-temperature environment is greatly deteriorated from the normal temperature, and there is a case where sufficient green sheet retention cannot be obtained in the high-temperature cutting process, and wafer splash or wafer shift occurs. Therefore, processing of a small, high-volume, high-capacity wafer becomes difficult.

In view of the above, there is a method in which the adhesion-imparting resin is added to the adhesive to increase the adhesive force and improve the retention of the adherend to the adhesive. Therefore, the adhesion is increased by the addition of the adhesion-imparting agent. Suppress wafer spatter. However, although the wafer splashes The frequency is slightly reduced, but it has nothing to do with the dramatic improvement. When the addition amount of the adhesion-imparting agent is further increased to increase the adhesion, the adhesion to the adhesive layer is sufficiently strong when the wafer is peeled off, which is a result of difficulty in peeling.

In order to eliminate such a phenomenon, it is known to use a non-thermally expandable releasable temporary fixing sheet to cut a green sheet as disclosed in Patent Document 1, and a heat-expandable adhesive layer containing a thermally expandable microsphere and a layered niobate is provided. The formed heat-peelable pressure-sensitive adhesive sheet is also known as described in Patent Document 2.

However, such known methods are not intended to maintain the retention characteristics of the wafer when the adhesive itself is heated.

Further, in the field of semiconductors, there is a need for a compound semiconductor such as an LED to be rapidly expanded, but a compound semiconductor is likely to be damaged by a small impact, and a back surface polishing or a wafer cutting step is performed when the wafer is thinned. Care must be taken when processing.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-52038

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-266455

The conventional heat-peelable adhesive sheet and tape cannot sufficiently eliminate the drop in yield caused by so-called "wafer splash" or the like due to insufficient adhesion in a high-temperature environment at the time of cutting.

Similarly, for example, when the semiconductor wafer is diced, the dicing blade becomes high in temperature due to friction, and the adhesive also becomes high in temperature, so that the shearing force of the adhesive sheet which is important for the retention of the wafer is lowered to cause "wafer splattering". Or the case of "wafer defect".

In order to solve such problems, for example, an operation of copolymerizing a monomer having a functional group such as acrylic acid with an acrylic copolymer to improve adhesion to a wafer component is performed. However, in the case of enhancing the adhesion of the adhesive, there is a part of being adhered to It is impossible to peel off when peeling.

Further, an adhesion-imparting agent (adhesion-imparting resin) may be added to improve adhesion. However, depending on the type of the adhesive, there is also a case where the adhesion-imparting agent having poor compatibility with the adhesive is present, and in this case, there is a case where the adhesion is decreased. Therefore, the adhesion-imparting agent must be strictly selected.

An object of the present invention is to prevent the wafer from being sufficiently fixed after the cutting in the cutting step of the wafer, and to prevent the wafer from splashing or the like during the cutting, thereby improving the yield when the wafer is cut.

The inventors of the present application have intensively studied to solve the above-mentioned problems, and have found that the composition containing the specific acrylic copolymer (A) and the crosslinking agent (B) can attain the above problems, and the present invention has been completed. That is, the present invention provides the following re-peeling adhesive composition, a re-peelable adhesive sheet using the same, and a cutting method for an electronic component.

The re-peeling adhesive composition of the present invention comprises an acrylic copolymer (A) and a crosslinking agent (B), and the monomer component constituting the acrylic copolymer (A) contains at least an alkyl group having a carbon number of a comonomer (b) having a glass transition temperature (Tg) of 80 or higher or higher and a functional group capable of reacting with the crosslinking agent (B) having an alkyl (meth) acrylate (a) or a homopolymer of 4 or less The ratio of the above-mentioned (meth)acrylic acid alkyl ester monomer (a) to the monomer (c) is 50% by weight or more based on the total amount of the monomer components.

Preferably, the ratio of the comonomer (b) is from 1 to 20% by weight based on the total amount of the monomer components constituting the acrylic copolymer (A), and the ratio of the monomer (c) is from 0.1 to 10 weight%.

Moreover, it is preferable that the monomer (c) is at least one of a carboxyl group-containing monomer, a carbonyl group-containing monomer, a hydroxyl group-containing monomer, and a glycidyl group-containing monomer.

Further, it is preferred that the comonomer (b) is methyl methacrylate, acrylonitrile or (meth)acrylic acid At least one of an ester, N,N-dimethylpropenylamine and N-propenylmorpholine.

The re-peeling adhesive composition of the present invention may further contain an adhesion-imparting agent.

The adhesion-imparting agent is preferably an indophenol resin having a hydroxyl value of 70 KOHmg/g or more.

The re-peeling adhesive composition of the present invention may further contain a foaming agent.

Preferably, the ratio of the re-peeling adhesive composition of the present invention to the dissolved component of the re-peeling adhesive composition to the dissolved component of toluene having a weight average molecular weight of 10,000 or less is 40% relative to the total amount of the re-peeling adhesive composition. the following.

Further, the re-peelable adhesive sheet of the present invention has a re-peeling adhesive layer comprising the re-peeling adhesive composition of the present invention.

It is preferred that the re-peeling adhesive sheet of the present invention has a shearing force at 23 ° C of 10 N / 25 mm × 25 mm or more.

Preferably, the re-peelable adhesive sheet has a substrate and a re-peeling adhesive layer formed of at least one side of the substrate by a re-peeling adhesive composition.

Further, the re-peeling adhesive layer may be directly provided on at least one side of the substrate.

Further, the re-peeling adhesive layer may be provided on at least one side of the substrate with a primer layer interposed therebetween.

Further, it is preferable that the thickness of the primer layer is 100 μm or less.

Preferably, the re-peelable adhesive sheet of the present invention is used in the cutting of electronic parts.

Further, it is preferable that the re-peelable adhesive sheet of the present invention is used for cutting a member for a ceramic capacitor.

The cutting method for an electronic component according to the present invention includes a step of bonding an electronic component to the re-adhesive sheet of the present invention, and a step of performing a cutting process on the electronic component.

According to the present invention, it is possible to perform a process such as cutting in a state in which the workpiece is temporarily fixed, whereby the cut wafer can be surely fixed, thereby preventing the wafer from being cut. Splash or offset, etc. occur.

Fig. 1 is a view showing a method of measuring shear adhesion.

Hereinafter, the re-peeling adhesive composition containing the acrylic copolymer (A) and the crosslinking agent (B) of the present invention, the re-peeling adhesive sheet, and the cutting method of the electronic component will be described in detail. Furthermore, in the present specification, "slice" is a concept including a tape.

The acrylic copolymer (A) is an acrylic copolymer in which one or two or more kinds of alkyl (meth)acrylates are used as a monomer component.

Examples of the alkyl (meth)acrylate include a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, a tert-butyl group, an isobutyl group, a pentyl group, an isopentyl group, and a hexyl group. Heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, decyl, isodecyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl An alkyl (meth)acrylate having a linear or branched alkyl group having a carbon number of 30 or less, such as a stearyl group, an octadecyl group or a dodecyl group. These may be used alone or in combination of two or more. In the present specification, the term "(meth)acrylic" means "acrylic" and/or "methacrylic".

In the present invention, in order to improve the adhesion at the time of processing and the peelability after the processing, it is preferred to use an alkyl (meth)acrylate having a linear or branched alkyl group having 4 or less carbon atoms (a). ). Specific examples of the alkyl (meth)acrylate (a) having 4 or less carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid. Propyl ester, butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, tert-butyl (meth)acrylate, etc., wherein the carbon number of the alkyl group is 4 or less The alkyl acrylate is preferably used, and ethyl acrylate or butyl acrylate is preferably used. The content of the alkyl (meth)acrylate (a) having a linear or branched alkyl group having 4 or less carbon atoms is relative to The total amount (100% by weight) of the monomer component constituting the acrylic copolymer is 50% by weight or more, preferably 55% by weight or more, and more preferably 80% by weight or more.

The acrylic copolymer (A) may contain a linear one having a carbon number of 5 or more, in addition to the alkyl (meth)acrylate (a) having a linear or branched alkyl group having 4 or less carbon atoms. Or an alkyl (meth)acrylate of a branched alkyl group. Specific examples of the alkyl (meth)acrylate having a linear or branched alkyl group having 5 or more carbon atoms include octyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate. As the isodecyl acrylate, decyl acrylate or the like, 2-ethylhexyl acrylate can be preferably used. In this case, the content of the alkyl (meth)acrylate having a linear or branched alkyl group having 5 or more carbon atoms is compared with the total amount of the monomer component (100% by weight) constituting the acrylic polymer. It is preferably 40% by weight or less, preferably 35% by weight or less.

The acrylic copolymer (A) may further contain a unit corresponding to another monomer component copolymerizable with the above (meth)acrylic acid alkyl ester. Examples of such a monomer component include carboxyl groups such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxy amyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Monomer; anhydride monomer such as maleic anhydride or itaconic anhydride; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyl group (meth)acrylate Hydroxyl-containing monomer such as hexyl ester, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl methacrylate ; styrene sulfonic acid, allyl sulfonic acid, 2-(methyl) propylene decylamine-2-methylpropane sulfonic acid, (meth) acrylamide propylene sulfonic acid, sulfopropyl (meth) acrylate, a sulfonic acid group-containing monomer such as (meth)acryloxynaphthalenesulfonic acid; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl (methyl) a (N-substituted) guanamine monomer such as acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide or the like; Ethyl ester, N,N-di(meth)acrylate Aminoalkyl (meth) acrylate monomer such as arylaminoethyl ester or tert-butylaminoethyl (meth)acrylate; methoxyethyl (meth)acrylate, (meth)acrylic acid (A) alkoxyalkyl (meth) acrylate monomer such as ethoxyethyl ester; N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl a maleimide-based monomer such as maleimide or N-phenyl maleimide; N-methyl Ikonide, N-ethyl Ikonide , N-butyl Ikonium imidate, N-octyl ikyl imine, N-2-ethylhexyl ketimine, N-cyclohexyl ketimine, N-Lauryl Ikon Ikonide imine monomer such as quinone imine; N-(methyl) propylene oxime methylene butyl quinone imine, N-(methyl) propylene fluorenyl-6-oxy hexamethylene Butadiene imine monomer such as butadiene imine, N-(methyl)propenyl-8-oxy octamethylbutanediimide; vinyl acetate, vinyl propionate, N- Vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiper Vinylpyr , vinyl pyrrole, vinyl imidazole, vinyl a vinyl monomer such as azole, vinylmorpholine, N-vinylcarboxamide, styrene, α-methylstyrene or N-vinyl caprolactam; cyano group such as acrylonitrile or methacrylonitrile Acrylate monomer; epoxy group-containing acrylic resin monomer such as glycidyl (meth)acrylate; (meth)acrylic acid polyethylene glycol ester, (meth)acrylic acid polypropylene glycol ester, (methyl) a diol-based acrylate monomer such as methoxyethylene glycol acrylate or methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, fluorenone a (meth) acrylate monomer having a hetero ring, a halogen atom or a ruthenium atom such as a (meth) acrylate; hexanediol di(meth) acrylate or (poly)ethylene glycol di(methyl) Acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol Tris (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, etc. Functional monomer; isoprene, butadiene, isobutylene and other olefin-based monomers; vinyl ether, vinyl ether-based monomers. These monomer components can be used alone or in combination of two or more.

In the present invention, in order to improve the cohesive force of the adhesive, the adhesion during processing, the adhesion of the adhesive to the substrate, and the removability of the adhesive tape after processing, the glass transition temperature of the homopolymer is used ( The comonomer (b) having a Tg) of 80 ° C or higher is used as another monomer component copolymerizable with the above alkyl (meth)acrylate. It is preferred to use a comonomer having a glass transition temperature (Tg) of a homopolymer of 90 ° C or higher, more preferably 100 ° C or higher. In particular, when it is used for the purpose of foaming and re-peeling a foaming agent or the like in an adhesive, the foaming state of the foaming agent during heating is stable, and re-peeling can be stably performed. Specific examples of such a comonomer include cyclohexyl methacrylate (Tg: 83 ° C), dicyclopentanyl acrylate (Tg: 120 ° C), and dicyclopentanyl methacrylate (Tg: 175). °C), acrylic acid Ester (Tg: 94 ° C), methacrylic acid Ester (Tg: 150 ° C), butyl methacrylate (Tg: 118 ° C), methyl methacrylate (Tg: 105 ° C), trimethylolpropane triacrylate (Tg: > 250 ° C), Styrene (Tg: 80 ° C), acrylonitrile (Tg: 97 ° C), N-propylene decylmorpholine (Tg: 145 ° C), N, N-dimethyl decylamine (Tg: 89 ° C), etc. Methyl methacrylate can be preferably used. Further, the Tg of the homopolymer of the alkyl (meth)acrylate other than the above can be judged according to "Polymer Handbook" (4th edition, John Wiley & Sons, Inc, 1999). Furthermore, in this document, when a plurality of Tg values are described, the value of "conventional" is used. The amount of the comonomer to be added is preferably from 1 to 20% by weight, and more preferably from 1 to 10% by weight, based on the total amount of the monomer component (100% by weight) constituting the acrylic copolymer.

In the present invention, the monomer (c) having a functional group reactive with the crosslinking agent (B) is used as a copolymerizable copolymer constituting the acrylic copolymer from the viewpoint of improving the adhesion at the time of processing. ingredient. Specific examples of the monomer having such a functional group include a carboxyl group-containing monomer, a carbonyl group-containing monomer, a hydroxyl group-containing monomer, and a glycidyl group-containing monomer. The amount of the monomer (c) having the functional group reactive with the crosslinking agent (B) is preferably 10% by weight based on the total amount of the monomer component (100% by weight) constituting the acrylic copolymer. The following (for example, 0.1 to 10% by weight or less) is particularly preferably 6% by weight or less (for example, 0.1 to 6% by weight or less).

As the above carboxylic acid group-containing monomer, for example, acrylic acid, methacrylic acid, and cis-butyl Acrylic acid anhydride or the like can be preferably used.

The carbonyl group-containing monomer is not particularly limited as long as it contains a ketone group and/or an aldehyde group, and examples thereof include diacetone acrylamide, diacetone methacrylamide, acrolein, and formamidine. Styrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, diacetone acrylate, diacetone methacrylate, acetonitrile acrylate, 2-hydroxypropyl acetate acetate , butanediol acrylate acetamidine acetate and the like. Among these, in particular, diacetone acrylamide can be preferably used.

As the hydroxyl group-containing monomer, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxyl (meth)acrylate As the butyl ester or the like, 2-hydroxyethyl acrylate can be preferably used.

The acrylic copolymer (A) can be produced by polymerizing the above monomer component by a known or conventional polymerization method, and examples thereof include a solution polymerization method, a bulk polymerization method, or a polymerization method by active energy ray irradiation (active energy). Line polymerization method) and so on. Among the above, in terms of transparency, water resistance, cost, and the like, a solution polymerization method and an active energy ray polymerization method are preferred, and a solution polymerization method is more preferred. Other polymerization methods include emulsion polymerization and the like. However, since an emulsifier, a chain transfer agent, or the like is used in the emulsion polymerization, contamination of the adherend is feared, which is not preferable in the present application. When the above solution is polymerized, various usual solvents can be used. Examples of such a solvent include esters such as n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; and alicyclic rings such as cyclohexane and methylcyclohexane. An organic solvent such as a hydrocarbon such as a ketone such as methyl ethyl ketone or methyl isobutyl ketone. These may be used alone or in combination of two or more. The acrylic copolymer of the adhesive used in the present application may be blended with at least two or more acrylic copolymers having different monomer composition ratios.

The weight average molecular weight of the acrylic copolymer is preferably at least 300,000 or more, and more preferably 400,000 or more from the viewpoint of removability. The weight average molecular weight (Mw) can be determined by a gel permeation chromatography (GPC) method. More specifically, it can be used The product name "HLC-8120GPC" (manufactured by Tosoh Co., Ltd.) was determined as a GPC measurement device by measuring the polystyrene conversion value under the measurement conditions of the following GPC.

GPC measurement conditions

. Sample concentration: 0.2% by weight (tetrahydrofuran solution)

. Sample injection amount: 10 μL

. Lysate: tetrahydrofuran (THF)

. Flow rate (flow rate): 0.6mL/min

. Column temperature (measuring temperature): 40 ° C

. Pipe column: trade name "TSKgelSuperHM-H/H4000/H3000/H2000" (manufactured by Tosoh Co., Ltd.)

. Detector: Differential Refractometer (RI)

In the re-peeling adhesive composition of the present invention, in order to further improve the re-peelability, a foaming agent may be formulated. As the foaming agent, an inorganic or organic foaming agent can be used. Examples of the inorganic foaming agent which is usually used include water, ammonium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate, ammonium nitrite, and hydrogen. Sodium boride, graphite, and the like.

Examples of the organic foaming agent include chlorofluorinated alkane such as trichloromonofluoromethane or dichloromonofluoromethane; azobisisobutyronitrile or azodimethylamine, hydrazine azodicarboxylate; An azo compound of an acid ester; p-toluenesulfonyl hydrazine or diphenyl hydrazine-3,3'-disulfonyl hydrazine, 4,4'-oxybis(phenylsulfonyl hydrazine), An oxime compound such as allyl bis(sulfonyl hydrazine); ρ-tolylsulfonyl semicarbazone or 4,4'-oxybis(phenylsulfonyl sulphonium) Carbene compound; triazole compound such as 5-morpholinyl-1,2,3,4-thiatriazole; N,N'-dinitrosopentamethylenetetramine or N,N' An N-nitroso compound such as dimethyl-N,N'-dinitroso-p-xylyleneamine or the like. Further, an azo compound or an azide compound which generates a gas by light or the like can also be used.

As a foaming agent which can be optimally used, a liquid having a low boiling point is enclosed in a shell. The heat-expandable microspheres of the microspheres may be, for example, a microsphere obtained by encapsulating a substance which is easily gasified and expanded by heating, such as isobutane, propane or pentane, in an elastic shell. In many cases, the shell is formed of a hot melt material or a substance that is destroyed by thermal expansion. Examples of the material for forming the above shell include a vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polyfluorene, and the like. . The heat-expandable microspheres can be produced by a conventional method such as a coacervation method, an interfacial polymerization method, or the like. In addition, as for the heat-expandable microspheres, for example, "Matsumoto Microsphere" manufactured by Matsumoto Oil & Fat Pharmaceutical Co., Ltd. (product names F-30, F-36LV, F-50, F-65, FN-100SS, FN-180SS) , F-190D, F-260D, F-2800D), "Expancel" manufactured by Japan Fillite Co., Ltd. (product names 053-40, 031-40, 920-40, 909-80, 930-120), Wu Yu "DAIFOAM" (product name H750, H850, H1100, S2320D, S2640D, M330, M430, M520) manufactured by Chemical Industry Co., Ltd., "ADVANCELL" manufactured by Sekisui Chemical Industry Co., Ltd. (product names EML101, EMH204, EHM301, Commercial products such as EHM302, EHM303, EM304, EHM401, EM403, EM501).

In the present invention, in order to improve the adhesion of the re-peeling adhesive composition, an adhesion-imparting agent can also be used. As such an adhesion-imparting agent, for example, a known or conventional adhesive-imparting agent (indophenol resin, rosin-based resin, petroleum resin, coumarone-indene resin, styrene-based resin, etc.) may be blended, and one or more types may be blended alone. Adhesive imparting agent. Among them, an indophenol resin can be preferably used.

The hydroxyl value of the adhesion-imparting resin is preferably 70 KOH mg/g or more. In particular, an acrylic copolymer (A) having a carbon number of alkyl (meth) acrylate monomer of 4 or less and having an alkyl (meth) acrylate monomer (a) as a main monomer is used. In the case where the hydroxyl value is less than 70 KOH mg/g, the compatibility with the acrylic copolymer is deteriorated, and the contamination due to the residual of the paste at the time of the characteristics or re-peeling is deteriorated. Further, the acid value of the adhesion-imparting resin is preferably 10 KOH mg/g or less, more preferably 7 KOH mg/g or less, and most Preferably it is 5 KOH mg/g or less. In the above-mentioned adhesion-imparting resin, a resin having an acid value of more than 10 KOH mg/g is used. When such an adhesion-imparting resin is used, when a crosslinking agent is blended in the acrylic copolymer, the adhesion-providing resin reacts with the crosslinking agent. Thereby reducing the reaction of the acrylic copolymer with the crosslinking agent. This cross-linking disorder is a cause, and the gel component of the adhesive is lowered, resulting in deterioration of contamination or re-peelability. The method for measuring the hydroxyl value or the acid value was evaluated in accordance with JIS K 0070-1992.

(Method for measuring hydroxyl value)

The hydroxyl value of the sample was evaluated in accordance with JIS K 0070-1992 (Ethyl acetate method). About 25 g of acetic anhydride was added and pyridine was added so that the total amount was 100 mL, and the mixture was sufficiently stirred to prepare an acetamidine reagent.

Accurately weigh about 2 g of the sample and place it in a flat-bottomed flask, add 5 mL of acetamidine reagent and 10 mL of pyridine, and install an air condenser. After heating at 100 ° C for 70 minutes, it was left to cool, and 35 mL of toluene was added as a solvent from the upper portion of the condenser, and the mixture was stirred. Then, 1 mL of water was added and stirred to decompose acetic anhydride. In order to complete the decomposition, it was heated again for 10 minutes and left to cool.

The condenser was washed with 5 mL of ethanol and removed, and 50 mL of pyridine was added as a solvent and stirred. To the solution, 25 mL of a 0.5 mol/L potassium hydroxide ethanol solution was added using a full pipette, and potentiometric titration was performed using a 0.5 mol/L potassium hydroxide ethanol solution, and a hydroxyl value was calculated according to the following formula (3).

B: The amount of 0.5 mol/L potassium hydroxide ethanol solution used in the blank test (mL)

C: The amount of 0.5 mol/L potassium hydroxide ethanol solution used in the sample (mL)

f: coefficient of 0.5 mol/L potassium hydroxide ethanol solution

S: the amount of sample taken (g)

D: acid value

(Method for measuring acid value)

The acid value of the sample was evaluated in accordance with JIS K 0070-1992 (potential difference titration method). To the solvent obtained by mixing diethyl ether and ethanol to a volume ratio of 4:1, a phenolphthalein solution was added as an indicator, and the mixture was neutralized with a 0.1 mol/L potassium hydroxide ethanol solution. Accurately weigh and take about 5 g of the sample in a beaker, add 50 mL of solvent, stir on a panel heater (80 ° C) to completely dissolve it, and perform potentiometric titration using a 0.1 mol/L potassium hydroxide ethanol solution. The acid value was determined according to the following formula (4).

B: The amount of 0.1 mol/L potassium hydroxide ethanol solution used in the sample (mL)

F: coefficient of 0.1 mol/L potassium hydroxide ethanol solution

S: the amount of sample taken (g)

Further, in the re-peeling adhesive composition of the present invention, it is preferable that the dissolved component having a weight average molecular weight of 10,000 or less in the dissolved component of p-toluene is preferably 40% or less based on the total amount of the re-peeling adhesive composition. Further, it is preferably 35% or less, more preferably 30% or less, still more preferably 25% or less, and most preferably 20% or less. If it contains more than 40%, it may have a bad influence on re-peelability and contamination. The method for measuring the weight average molecular weight of the re-peeling adhesive composition to the dissolved component of toluene is measured by the method described in detail below.

<Method for Measuring Weight Average Molecular Weight of Dissolved Components of Toluene>

Weighed and accurately weighed the sample (mass: W _a1 mg), and made a porous film made of tetrafluoroethylene resin having an average pore diameter of 0.2 μm (NITOFLON (registered trademark) NTF1122 manufactured by Nitto Denko Co., Ltd.) (average pore size 0.2 μm, The porosity is 75%, the thickness is 0.085 mm)) (mass: W _a2 mg) is wrapped into a waist pack, and the mouth is tied with a kite line (mass: W _a3 mg). The capacity of 50mL placed parcel (in the state without cover previously measured capacity of the main mass of the spiral 50mL: W _a4 mg) in a spiral (per one package using a spiral tube), in the helical tube filled with toluene. After leaving it at 23 ° C for 7 days, the above-mentioned package was taken out and the toluene solution in which the sol component was dissolved was dried under reduced pressure at 30 ° C to measure the weight of the spiral tube in the state of the solid matter containing the sol component (mass: W _a5 mg) The sol component (mass: W _a6 mg) was calculated.

W _a6 =(W _a5 -W _a4 )

The molecular weight of the sol component was then measured by GPC (gel permeation chromatography).

The weight average molecular weight (Mw) of the solid content component of the sol component can be measured by a gel permeation chromatography (GPC) method. More specifically, the product name "HLC-8120GPC" (manufactured by Tosoh Co., Ltd.) can be used as a GPC measuring device, and can be obtained by measuring the polystyrene-converted value under the measurement conditions of the following GPC.

GPC measurement conditions

. Sample concentration: 0.2% by weight (tetrahydrofuran solution)

. Sample injection amount: 10 μL

. Lysate: tetrahydrofuran (THF)

. Flow rate (flow rate): 0.6mL/min

. Column temperature (measuring temperature): 40 ° C

. Pipe column: trade name "TSKgelSuperHM-H/H4000/H3000/H2000" (manufactured by Tosoh Co., Ltd.)

. Detector: Differential Refractometer (RI)

The ratio Wm (%) of the weight average molecular weight of 10,000 or less is calculated from the curve of the weight average molecular weight of the sol component as a whole, and the sample is calculated as a dissolved component of toluene in the form of a ratio A ₁₀₀₀₀ (%) to the entire sample. A dissolved component having a weight average molecular weight of 10,000 or less.

A ₁₀₀₀₀ (%) = [W _a6 (mg) × Wm (%) / W _a1 (mg)] × 100

The crosslinking agent (B) to be blended as the re-peeling adhesive composition is, for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a melamine-based crosslinking agent, or a peroxide-based crosslinking agent. : a urea-based crosslinking agent, a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, a metal salt crosslinking agent, a carbon diimide crosslinking agent, As the oxazoline crosslinking agent, the aziridine crosslinking agent, the amine crosslinking agent, and the like, an isocyanate crosslinking agent or an epoxy crosslinking agent can be preferably used.

(isocyanate crosslinking agent)

Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; cyclopentyl diisocyanate and diisocyanate ring An alicyclic isocyanate such as an ester or isophorone diisocyanate; an aromatic isocyanate such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate or benzodimethyl diisocyanate; Propane/toluene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Japan Polyurethane Industry Co., Ltd.), trimethylolpropane/hexamethylene diisocyanate trimer adduct (trade name Coronate HL) , manufactured by Japan Polyurethane Industry Co., Ltd.), an isocyanate adduct such as hexamethylene diisocyanate isocyanurate (trade name: Coronate HX, manufactured by Japan Polyurethane Industry Co., Ltd.). These compounds may be used singly or in combination of two or more.

In the case of using an isocyanate crosslinking agent, a catalyst or the like can also be used. For example, tin dioctyltin laurate (EMBILIZER OL-1, manufactured by Tokyo Fine Chemical Co., Ltd.) or other usual amine or organometallic catalyst can be used. The blending amount of the isocyanate crosslinking agent can be appropriately determined depending on the adhesion to be controlled. Usually, 1 to 20 parts by weight, preferably 1 to 10 parts by weight, per 100 parts by weight of the base polymer are blended.

(epoxy crosslinker)

As the above epoxy-based crosslinking agent, for example, N,N,N',N'-tetraglycidyl meta-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-glycidol) Aminomethyl)cyclohexyl Alkane (product name "Tetrad C", manufactured by Mitsubishi Gas Chemical Co., Ltd.), 1,6-hexanediol diglycidyl ether (product name "Epolight 1600", manufactured by Kyoeisha Chemical Co., Ltd.), Niigata Alcohol diglycidyl ether (product name "Epolight 1500NP", manufactured by Kyoeisha Chemical Co., Ltd.), ethylene glycol diglycidyl ether (product name "Epolight 40E", manufactured by Kyoeisha Chemical Co., Ltd.), propylene glycol II Glycidyl ether (product name "Epolight 70P", manufactured by Kyoeisha Chemical Co., Ltd.), polyethylene glycol diglycidyl ether (product name "EPIOL E-400", manufactured by Nippon Oil Co., Ltd.), polypropylene glycol II Glycidyl ether (product name "EPIOL P-200", manufactured by Nippon Oil & Fat Co., Ltd.), sorbitol polyglycidyl ether (product name "DENACOL EX-611", manufactured by Nagase ChemteX Co., Ltd.), glycerol polyglycidyl Ether (product name "DENACOL EX-314", manufactured by Nagase chemteX Co., Ltd.), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (product name "DENACOL EX-512", Nagase chemt Manufactured by eX Co., Ltd., sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, tris(2-hydroxyethyl) In addition to the triglycidyl isocyanurate, the resorcinol diglycidyl ether, and the bisphenol-S-diglycidyl ether, an epoxy resin having two or more epoxy groups in the molecule may be mentioned. These crosslinking agents may be used singly or in combination of two or more.

The amount of the epoxy-based crosslinking agent can be appropriately determined depending on the control adhesion. Usually, 0.1 to 5 parts by weight, preferably 0.1 to 3 parts by weight, per 100 parts by weight of the base polymer are blended.

The crosslinking agent which can be used in the present invention is not particularly limited, and examples thereof include epoxy-based, isocyanate-based, guanidine-based, melamine-based, and carbodiimide-based. An oxazoline system, a metal chelate compound, and the like.

Examples of the other additives include a filler (including glass particles and the like), a colorant (pigment or dye), an antioxidant, an ultraviolet absorber, and an interfacial activity. Various known additives such as a agent, a plasticizer, and conductive particles.

The re-peelable adhesive sheet of the present invention has at least a re-peeling adhesive layer formed of the above-mentioned re-peeling adhesive composition. An adhesive sheet in which the re-peeling adhesive layer is provided on one side or both sides of a sheet-like substrate (support) (so-called adhesive sheet with a substrate) may be used, or the above-mentioned re-peelable adhesive may be used. The adhesive layer is provided on, for example, a form of a release sheet of a separator (a form in which a base material supporting the adhesive layer is removed to remove a release liner) (a so-called substrate-free adhesive sheet).

As the base material, for example, a plastic base material is often used, but the plastic base material is not particularly limited, and paper, metal foil, woven fabric, fiber, or the like can be used. Examples of the raw material of the plastic base material include polyester (polyethylene terephthalate, polyethylene naphthalate, polyethylene terephthalate, polybutylene naphthalate, etc.). , polyolefin (polyethylene, polypropylene, polymethylpentene, ethylene-propylene copolymer, etc.), polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate Ester, polyamide, polyimine, cellulose, fluorine resin, polyether, polyether amide, polyether nitrile, polyether ether ketone, polyphenylene sulfide, polystyrene resin (polystyrene) Etc.), polycarbonate, polyether oxime, etc. These may be used alone or in combination of two or more. In the present invention, in terms of heat resistance, a resin selected from the group consisting of polyesters such as polyethylene terephthalate and polyolefins such as polypropylene, polyimine and fluorine resins is preferably used. The substrate of the raw material. The thickness of the substrate is not particularly limited, but is preferably about 8 to 300 μm, more preferably about 10 to 200 μm. If the thickness of the base material is less than the above range, the strength of the adhesive tape is insufficient, which may impair the practicality.

The substrate may be a single layer or a laminate of two or more layers. In the case where the substrate is a laminate of two or more layers, each layer may have the same composition, or may be laminated by combining layers of different compositions.

Further, in order to improve the gripping force with the adhesive layer or the like, the surface of the substrate may be subjected to surface treatment as needed, for example, by corona treatment, chromic acid treatment, ozone exposure, flame storm The surface free energy of the surface of the substrate is preferably 35 mN/m or more, such as exposure, high-voltage electric shock exposure, ionizing radiation, oxidation treatment by chemical or physical methods such as metal sodium treatment.

In order to improve the grip of the substrate and the re-adhesive layer, it is also possible to provide a primer layer on the side of the adhesive layer of the substrate. The primer layer is a layer provided as needed, and may not necessarily be provided.

In the case where the foaming agent is contained in the above-mentioned re-peeling adhesive composition, it is preferred to provide a substrate and a re-peeling adhesive from the viewpoint of imparting deformability to the re-peelable adhesive sheet or improving the peeling property after heating. A primer layer is disposed between the layers. In this manner, by providing the primer layer, the re-peeling adhesive sheet including the re-peeling adhesive composition containing the foaming agent is adhered to the adherend (processed product, etc.) The surface of the re-adhesive adhesive layer satisfactorily follows the surface shape of the adherend, thereby increasing the adhesion area. Moreover, when the re-peelable adhesive sheet is heated and peeled off from the adherend, the thermal expansion of the re-adhesive adhesive layer can be controlled with high precision (precision), and the re-peeling adhesive layer can be preferentially and uniformly expanded in the thickness direction. That is, the primer layer is provided to provide a large contact area when the surface of the adherend adheres to the surface of the adherend when the re-peelable adhesive sheet and the adherend are attached. In addition, the primer layer also has the function of reducing the foaming of the re-peelable adhesive sheet in the surface direction in order to peel off the adherend from the re-peelable adhesive sheet and to heat and then peel the adhesive layer to cause foaming and/or expansion. / or expansion constraints, and then peeling the adhesive layer to undergo a three-dimensional structural change, thereby promoting the formation of the relief structure.

In the case where the adhesive sheet is a substrate-attached adhesive sheet, the primer layer is preferably disposed between the sheet substrate and the re-peeling adhesive layer, and the primer layer may be disposed on the substrate. Face or two sides. Further, in the case where the adhesive sheet is a substrate-free adhesive sheet, the primer layer is preferably provided on the surface of the re-peeling adhesive layer opposite to the side to which the adherend side is attached.

The primer layer may be an adhesive layer, and the material thereof is not particularly limited, and an adhesive or the like exemplified as the above-mentioned re-peeling adhesive composition can be preferably used as a constituent material. The adhesive may be an acrylic adhesive, a rubber adhesive, a vinyl alkyl ether adhesive, an anthrone adhesive, a polyester adhesive, a polyamide adhesive, or a urethane. The adhesive, the styrene-diene block copolymer-based adhesive, the creep-modified adhesive, and the radiation-curable adhesive are appropriately selected.

More specifically, for example, a rubber-based adhesive using natural rubber or synthetic rubber as a base polymer, an acrylic adhesive having a (meth)acrylic polymer as a base polymer, and the like: Acrylic polymer has methyl, ethyl, propyl, butyl, 2-ethylhexyl, isooctyl, isodecyl, isodecyl, dodecyl, lauryl, tridecyl , pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, etc., such as acrylic acid or methacrylic acid having an alkyl group having a carbon number of 20 or less (methyl) Acrylic alkyl ester, acrylic acid, methacrylic acid, itaconic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, N-methylol acrylamide, propylene Nitrile, methacrylonitrile, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, styrene, isoprene, butadiene, isobutylene, vinyl ether or the like as a main component.

The primer layer may be formed of natural rubber, synthetic rubber or a synthetic resin having rubber elasticity in addition to the above-mentioned adhesive. Examples of the synthetic resin include synthetic rubbers such as nitrile-based, diene-based, and acrylic-based resins; thermoplastic elastomers such as polyolefins and polyesters; and ethylene-vinyl acetate copolymers and polyurethanes. A rubber-elastic synthetic resin such as polybutadiene or soft polyvinyl chloride.

Further, even if it is a hard polymer as in the case of polyvinyl chloride or the like, it can be used by expressing a rubber elasticity by a combination with a compounding agent such as a plasticizer or a softener.

Further, the primer layer including the materials may be a crosslinking agent, an adhesion-imparting resin, a plasticizer, a filler, and an anti-aging agent in the adhesive or synthetic resin as in the above-mentioned re-peeling adhesive layer. Suitable additives such as agents.

The formation of the primer layer can be carried out, for example, in the following manner: A method in which a coating liquid of a constituent material of a coating layer is applied onto a sheet substrate (coating method), a film including a rubber-like organic elastic layer forming material, or a thermal expansion adhesive layer including one or more layers in advance a laminated film having a layer of the rubber-like organic elastic layer forming material and a sheet-form substrate formed thereon (dry lamination method), a resin composition containing a constituent material of the sheet-form substrate, and the rubber-like material A method of co-extruding a resin composition of an organic elastic layer forming material (co-extrusion method) or the like.

Further, the primer layer may be formed of a foamed film or the like mainly composed of the components. The foaming can be carried out by a conventional method such as a method of mechanical stirring, a method of generating a gas by a reaction, a method of using a foaming agent, a method of removing a soluble substance, a method of spraying, a method of forming a coagulation bubble, and sintering. Law and so on. The rubber-like organic elastic layer may be composed of a laminated structure including a single layer or a layer of two or more layers.

The primer layer has a thickness of 0.1 to 100 μm, preferably 0.1 to 50 μm, more preferably 0.1 to 5 μm. As long as it is in such a range, it is not too thin, and it can exhibit the function of providing a large contact area following the surface shape of the adherend by the re-peelable adhesive sheet, and promoting the three-dimensional structural change with the re-peeling adhesive layer. The function of the undulating structure. Further, since it is not thicker than necessary, it does not cause aggregation failure in the rubber-like organic elastic layer after foaming.

As a protective material for protecting the surface (adhesive surface) of the re-peeling adhesive layer or the like before use, such as during storage or transfer, a spacer for covering the surface may be used, but the spacer may be used as needed, and may not necessarily be used. use. As the separator, the both surfaces may be the release surface, or the one surface (one surface) may be the release surface. Further, the separator is peeled off when the adhesive layer protected by the separator is used.

As such a separator, a known or conventional release paper or the like can be used.

Specifically, as the separator, for example, a substrate having a release agent layer such as a plastic film or paper which has been surface-treated with a release agent such as an anthrone-based, a long-chain alkyl group, a fluorine-based or a molybdenum sulfide can be used. ; including PTFE, polychlorotrifluoroethylene, polyvinyl fluoride, polyethylene a low-adhesive substrate of a fluorine-based polymer such as a vinyl fluoride, a tetrafluoroethylene-hexafluoropropylene copolymer or a chlorofluoroethylene-vinylidene fluoride copolymer; and an olefin-based resin (for example, polyethylene, polypropylene, etc.) A low-adhesive substrate or the like of a non-polar polymer. Of course, in the case of a substrate having a release agent layer, the surface of the release agent layer is a release surface, and if it is a low adhesion substrate, the surface of the low adhesion substrate is a release surface.

The shearing force at 23 ° C of the above-mentioned re-peelable adhesive sheet is preferably 10 N / 25 mm × 25 mm or more, and further preferably 20 N / 25 mm × 25 mm or more. By setting it as such a range, it is possible to prevent the component from splashing during processing, and it is possible to obtain a re-peelable adhesive sheet having good peelability after processing.

After adhering the above-mentioned re-peelable adhesive sheet to a polyethylene terephthalate film (thickness: 25 μm) at 23 ° C, the adhesion of the adhesive layer at 23 ° C was further removed at 23 ° C for 30 minutes ( The peeling angle: 180°, the stretching speed: 300 mm/min) is preferably 0.2 to 20 N/20 mm width, preferably 0.5 to 20 N/20 mm width. When the adhesive force in the environment of 23 ° C is 0.2 to 20 N / 20 mm width, the adherend can be sufficiently held, and the wafer is not peeled off during the cutting process. When the adhesion is less than 0.2 N/20 mm, it is difficult to sufficiently hold the adherend, and peeling of the wafer occurs during the cutting process. Further, when the adhesive force is 20 N/20 mm or more, there is a case where the adhesive is not peeled off from the adherend.

In the above-mentioned re-peelable adhesive sheet, when a re-peeling adhesive layer containing a foamed layer is provided on one surface of the substrate, the other side of the substrate may be provided, for example, to fix the re-peelable adhesive sheet to at least The adhesive layer of the base which is prepared by fixing the object to be fixed while the object to be fixed is being fixed, such as when the object to be cut is cut. The adhesive layer at this time must also be stable to heat or vibration generated during processing such as cutting. As the adhesive layer, for example, a resin used as the above-mentioned adhesive can be used as a basis.

(Method of using the heat-peelable adhesive tape of the present invention)

The re-peelable adhesive sheet of the present invention can be used to make electricity when specifically cutting off electronic parts. The adhesive tape that the sub-parts are fixed on the substrate. The electronic component to be cut is a capacitor, an inductor, or a coil, or a resistor, or a piezoelectric element, or an oscillator, or an electronic component such as an LED, a semiconductor, or a display device, which is cut by an arbitrary mechanism. Broken electronic parts. It is especially preferable to use when cutting off the member for ceramic capacitors.

The electronic component is bonded and fixed on the substrate via the re-peeling adhesive sheet of the present invention by adhesive force. Thereafter, the electronic component is cut by any method such as a cutting method by a dicing blade or a cutting method by a rotary blade, and thereafter, the electronic component is picked up from the detached adhesive sheet of the present invention. In particular, when the foaming agent is contained in the re-adhesive adhesive layer, by foaming the re-peeling adhesive layer, the adhesion of the cut electronic component to the re-peeling adhesive layer can be lowered, thereby picking up Electronic parts that have been cut.

[Examples]

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by the examples. The evaluation methods in the examples are as follows. Further, in the examples, "parts" and "%" are based on weight unless otherwise specified.

(1) (Method for measuring adhesion)

The adhesive tape or sheet of the examples and the comparative examples was cut into a size of 20 mm in width and 140 mm in length, and after peeling off the separator on the side of the adhesive layer, it was adhered to the adhesive layer in accordance with JIS Z 0237 (2000). Polyethylene terephthalate film (trade name "Lumirror S-10" manufactured by Toray Co., Ltd.; thickness: 25 μm, width 30 mm) (specifically, at temperature: 23 ± 2 ° C and humidity: 65 In a ±5% RH environment, a 2 kg roller is subjected to one-way crimping and lamination), and placed in a tensile tester equipped with a thermostat set at 23 ° C (trade name "Shimadzu Auto-stereograph AG- 120kN", manufactured by Shimadzu Corporation, and placed for 30 minutes. After standing, the load to be peeled off from the adhesive tape or sheet of the examples and the comparative examples at a peeling angle of 180° and a stretching speed of 300 mm/min was measured (the load at the peak of the initial stage of the measurement was removed). Maximum) as adhesion.

(2) Method for measuring shear adhesion

The adhesive sheets obtained in the examples and the comparative examples were cut into a size of 20 mm in width and 20 mm in length to obtain test pieces.

Using a 5 kg load for 5 minutes, the surface of the adhesive layer of the obtained test piece was adhered to a stainless steel plate (SUS304BA, ground by sandpaper No. 360) to be adhered, and then left at 23 ± 2 ° C for 0.5 hour.

After standing, the test piece and the stainless steel plate were measured in a different direction (opposite direction) at a tensile speed of 50 mm as shown in Fig. 1 under the conditions of temperature: 23 ± 2 ° C and humidity: 65 ± 5% RH. The load (maximum load) at the time of stretching under the condition of /min is used as the shear adhesion.

(3) Heat stripping

The adhesive sheets 12 cm×12 cm obtained in the examples (except for the second embodiment and the eleventh embodiment) and the comparative examples were bonded to a stainless steel plate SUS304-BA of 15 cm×15 cm (thickness: 1 mm), and the cutting conditions were cut as described below. After the SUS304 plate was cut, it was heat-treated at 150 ° C for 10 minutes using a thermostat (hot air dryer) ("SPH-201" manufactured by ESPEC Co., Ltd.). After the heating, the peeling state of the SUS304 plate from the adhesive sheet was visually observed, and the case where all the wafers were peeled off was judged to be good (○), and the case where one piece was not peeled off was judged to be defective (×).

(cutting processing conditions)

Ambient temperature: room temperature (23 ° C)

Cutting device: DFD651 manufactured by DISCO

Cutting speed: 30mm/sec

Cutting blade: GIA850 manufactured by DISCO

Cutting blade revolutions: 30000rpm

Cutting depth: 25μm

Cutting size: 10mm × 10mm

Cutting mode: smooth

(4) Separation evaluation of small pieces after cutting

The laminated ceramic sheets of 40 × 50 mm (thickness: 500 μm) were bonded to the adhesive sheets obtained in Examples 1, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13 and 14 and Comparative Examples. In the cutting device "G-CUT8AA" manufactured by UHT, the laminated ceramic sheet on the adhesive sheet was cut into a sub-network shape so as to be a small piece of 1 mm × 0.5 mm.

The foaming agent which was heat-treated at 150 ° C for 10 minutes was foamed by using a thermostat (hot air dryer) ("SPH-201" manufactured by ESPEC Co., Ltd.), thereby peeling off the small piece from the adhesive sheet, and calculating the cut. The number of wafers that are not separated between the wafers of the portion. The number of wafers obtained by dividing the number of unseparated wafers by 100% completely separated is used as an index of separation. When the index is less than 2%, it is denoted by ◎, and the index is 2% or more and less than 5% is denoted by ○, and the index of 5% or more and less than 15% is denoted by Δ, and the index of 15% or more is denoted by ×.

Details of the composition of the laminated ceramic sheet and the cutting conditions of the cutting device are as follows.

(Laminated ceramic sheets)

100 parts of barium titanate powder, 15 parts of polyvinyl butyral resin, 6 parts of bis(2-ethylhexyl) phthalate, and 2 parts of diglyceryl stearate were added to a toluene solvent, and the ball mill disperser was used. The mixture was mixed and dispersed, whereby a toluene solution as a dielectric was obtained. The solution was applied to a polyethylene terephthalate film having a surface treated with an anthrone release agent by using an applicator, and the thickness of the solution was 50 μm (manufactured by Mitsubishi Polyester Film Co., Ltd., trade name) The "MRF38", thickness: 38 μm) was applied to the release agent treatment surface and dried to obtain a ceramic sheet. The obtained ceramic sheet was laminated in a plurality of sheets so as to have a thickness of 500 μm to obtain a laminated ceramic sheet.

(cutting condition)

. Cutting temperature: 60 ° C, cutting depth (residual amount from the table top): about 20 μm

. Cutting knife: "U-BLADE2" manufactured by UHT Co., Ltd.: knife thickness 50μm, tip angle 15°

(5) Cut surface cutting evaluation

The laminated ceramic sheet was cut into a sub-network shape so as to be a small piece of 1 mm × 0.5 mm in the same manner as the evaluation of the separation property of the small pieces after the cutting. Select any 10 pieces from the cut pieces, and observe the cut surface with a magnifying glass of 50 times to confirm the presence or absence of fragments (defects of the laminated ceramic sheets due to cutting processing), and average the total number of pieces generated in 10 small pieces. The value is set to the indicator. When the index is 0 to less than 10, it is denoted by ◎, and 10 or more and less than 20 are denoted by ○, and 20 or more and less than 40 shall be denoted by Δ, and 40 or more shall be denoted by ×.

(6) Grabber property of the substrate and the adhesive layer (Examples 3 to 8)

The adhesive sheet was attached to the laminated ceramic sheet in the same manner as in the above (5), and subjected to cutting and heat treatment, and then the "bumping" of the adhesive layer from the substrate was visually observed. The case where the "lift" is not seen is judged as good (○), and the case where the "lift" is seen is judged as bad (×).

(7) Method for determining hydroxyl value and acid value

(Method for measuring hydroxyl value)

The hydroxyl value of the sample was evaluated in accordance with JIS K 0070-1992 (Ethylation Method). About 25 g of acetic anhydride was added and pyridine was added so that the total amount was 100 mL, and the mixture was sufficiently stirred to prepare an acetamidine reagent.

Accurately weigh and take about 2 g of the sample in a flat-bottomed flask, add 5 mL of acetamidine reagent and 10 mL of pyridine, and install an air condenser. After heating at 100 ° C for 70 minutes, it was left to cool, and 35 mL of toluene as a solvent was added from the upper portion of the condenser tube and stirred, and then 1 mL of water was added thereto and stirred to decompose acetic anhydride. In order to completely decompose the decomposition for another 10 minutes and place to cool.

The condenser was washed with 5 mL of ethanol and removed, and 50 mL of pyridine as a solvent was added and stirred. To the solution, 25 mL of a 0.5 mol/L potassium hydroxide ethanol solution was added using a full pipette, and potentiometric titration was performed using a 0.5 mol/L potassium hydroxide ethanol solution, and a hydroxyl value was calculated according to the following formula (3).

B: The amount of 0.5 mol/L potassium hydroxide ethanol solution used in the blank test (mL)

C: The amount of 0.5 mol/L potassium hydroxide ethanol solution used in the sample (mL)

f: coefficient of 0.5 mol/L potassium hydroxide ethanol solution

S: the amount of sample taken (g)

D: acid value

(Method for measuring acid value)

The acid value of the sample was evaluated in accordance with JIS K 0070-1992 (potential difference titration method). To the solvent obtained by mixing diethyl ether and ethanol to a volume ratio of 4:1, a phenolphthalein solution was added as an indicator, and the mixture was neutralized with a 0.1 mol/L potassium hydroxide ethanol solution. Accurately weigh and take about 5 g of the sample into a beaker, add 50 mL of solvent, stir on a panel heater (80 ° C) to completely dissolve it, and perform potentiometric titration with a 0.1 mol/L potassium hydroxide ethanol solution. The acid value was determined according to the following formula (4).

B: The amount of 0.1 mol/L potassium hydroxide ethanol solution used in the sample (mL)

F: coefficient of 0.1 mol/L potassium hydroxide ethanol solution

S: the amount of sample taken (g)

(8) Evaluation of pollution

Each of the adhesive sheets obtained in the examples and the comparative examples was attached to a surface of a stainless steel plate SUS304-BA of 15 cm × 15 cm (thickness: 1 mm) without leaving air bubbles by a hand roll, and left for 1 hour. The mixture was heated in a hot air dryer at 130 ° C for 3 minutes and then placed at 23 ° C for 2 hours. Each of the adhesive sheets was peeled off, and the turbidity of the enamel wafer surface was visually observed, and even a slight blur was recorded as ×.

(9) Method for measuring weight average molecular weight of dissolved components of toluene

Weighed and accurately weighed the sample (mass: W _a1 mg), and made a porous film made of tetrafluoroethylene resin having an average pore diameter of 0.2 μm (NITOFLON (registered trademark) NTF1122 manufactured by Nitto Denko Co., Ltd.) (average pore size 0.2 μm, The porosity is 75% and the thickness is 0.085 mm)) (mass: W _a2 mg) is wrapped into a waist pack, and the mouth is tied with a kite line (mass: W _a3 mg). The package was placed in a spiral tube having a capacity of 50 mL (predetermined in a state of no cover, a main mass of a 50 mL spiral tube: W a ₄ mg) (one spiral tube per one package), and the spiral tube was filled with toluene. After leaving it at 23 ° C for 7 days, the above-mentioned package was taken out, and toluene was dried under reduced pressure from a toluene solution in which a sol component was dissolved at 30 ° C, and the weight of the spiral tube in the state of the solid matter containing the sol component was measured. :W _a5 mg) Calculate the sol component (mass: W _a6 mg).

W _a6 =(W _a5 -W _a4 )

The molecular weight of the sol component was then measured by GPC (gel permeation chromatography).

The weight average molecular weight (Mw) of the solid content of the above sol component can be measured by a gel permeation chromatography (GPC) method. More specifically, the product name "HLC-8120GPC" (manufactured by Tosoh Co., Ltd.) can be used as a GPC measuring device, and can be obtained by measuring the polystyrene-converted value under the measurement conditions of the following GPC.

GPC measurement conditions

. Sample concentration: 0.2% by weight (tetrahydrofuran solution)

. Sample injection amount: 10 μL

. Lysate: tetrahydrofuran (THF)

. Flow rate (flow rate): 0.6mL/min

. Column temperature (measuring temperature): 40 ° C

. Pipe column: trade name "TSKgelSuperHM-H/H4000/H3000/H2000" (manufactured by Tosoh Co., Ltd.)

. Detector: Differential Refractometer (RI)

The ratio Wm (%) of the weight average molecular weight of 10,000 or less is calculated from the curve of the weight average molecular weight of the sol component as a whole, and the sample is calculated as a dissolved component of toluene in the form of a ratio A ₁₀₀₀₀ (%) to the entire sample. A dissolved component having a weight average molecular weight of 10,000 or less.

A ₁₀₀₀₀ (%) = [W _a6 (mg) × Wm (%) / W _a1 (mg)] × 100

The base film used in the polymer preparation method, the primer adjustment method, the examples of the present invention, and the comparative examples will be described in detail below.

[Polymer Synthesis Example 1]

86 parts by weight of butyl acrylate, 10 parts by weight of methyl methacrylate, 4 parts by weight of acrylic acid, and a polymerization initiator (trade name "Nyper BW") were added to a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirring device. 0.4 parts by weight of ethyl acetate and 100 parts by weight of ethyl acetate were subjected to polymerization treatment in a nitrogen stream at 60 ° C for 8 hours to obtain an acrylic copolymer.

The acrylic copolymers of Synthesis Examples 1 to 18 described in Table 1 were obtained in accordance with Synthesis Example 1.

[Substrate preparation example]

Primer A: 50 parts by weight of the acrylic copolymer obtained in Synthesis Example 13 and a trifunctional isocyanate compound (trade name "Coronate L", Japan Polyurethane Industrial Co., Ltd. were blended in a ratio of 50 parts by weight to the solid content. Co., Ltd. manufactured) to obtain a primer A having a solid content of 5% in toluene.

Primer B: 100 parts by weight (solid content) of the acrylic copolymer obtained in Synthesis Example 13 and 5 parts by weight of a trifunctional isocyanate compound (trade name "Coronate L", manufactured by Japan Polyurethane Industry Co., Ltd.) (Solid component) to obtain primer B.

[Examples. Substrate film used in the comparative example]

The base film A1 was applied to the product name "Lumirror S10 #100" (manufactured by Toray Co., Ltd.) and the primer A was applied and dried to a thickness of 1 μm after drying.

Substrate film A2: under the trade name "Lumirror S10#100" (Toray Co., Ltd. The primer B was applied and dried to have a coating thickness after drying of 30 μm.

Substrate film A3: trade name "Lumirror S10#100" (manufactured by Toray Co., Ltd.)

Substrate film B: An adhesive was directly applied to a single-sided corona treatment type product name "Lumirror S105 #100" (manufactured by Toray Co., Ltd.).

(Example 1)

100 parts by weight of the acrylic copolymer (solid content) of the polymer synthesis example 1 and 0.5 part by weight of an epoxy-based crosslinking agent (Tetrad-C manufactured by Mitsubishi Gas Chemical Co., Ltd.), and the product name "Expancel" as a heat-expandable microsphere. 920-40" (manufactured by Japan Fillite Co., Ltd.) was blended in a ratio of 30 parts by weight to obtain an acrylic adhesive.

The obtained acrylic pressure-sensitive adhesive was applied onto the primer surface of the base film A1 so as to have a thickness of 35 μm after drying, and dried, and the release-treated film was bonded to obtain a re-peelable pressure-sensitive adhesive sheet.

(Examples 2 to 12, Comparative Examples 1 to 6)

In Examples 2 to 12 and Comparative Examples 1 to 6, the re-peelable adhesive sheets were obtained in the same manner as in Example 1 except that the respective compositions and components were set as shown in Table 2. Further, the evaluation results are also shown in Table 2.

Coronate L isocyanate crosslinker (manufactured by Japan Polyurethane Industry Co., Ltd.)

Tetrad C epoxy crosslinker: (Mitsubishi Gas Chemical Co., Ltd.)

YS Polyster U115 phenolic resin (manufactured by YASUHARA CHEMICAL Co., Ltd.)

YS Polyster T115 Indophenol Resin (manufactured by YASUHARA CHEMICAL Co., Ltd.)

YS Polyster S145 phenolic resin (manufactured by YASUHARA CHEMICAL Co., Ltd.)

Mighty Ace G125 phenolic resin (manufactured by YASUHARA CHEMICAL Co., Ltd.)

Mighty Ace k125 phenolic resin (manufactured by YASUHARA CHEMICAL Co., Ltd.)

SUMILITE RESIN PR12603 Indophenol resin (manufactured by SUMITOMO BAKELITE Co., Ltd.)

920-40 Thermal expansion microcapsule (manufactured by Japan Fillite Co., Ltd.)

As can be seen from Table 2, the re-peelable adhesive sheet of the present invention is subjected to cutting processing in a state in which the workpiece is temporarily fixed, whereby the cut wafer can be surely fixed, and excellent cutting precision can be achieved. Moreover, it is non-polluting when peeled off, and has good peelability.

Further, the present invention will be described in detail with reference to the specific embodiments thereof. It is obvious that various changes and modifications may be made without departing from the spirit and scope of the invention.

The present application is based on Japanese Patent Application No. 2013-151141, filed on Jan. 19, 2013, the content of which is incorporated herein by reference.

Claims (14)

A re-peeling adhesive composition comprising an acrylic copolymer (A) and a crosslinking agent (B), and the monomer component constituting the acrylic copolymer (A) contains at least an alkyl carbon a methacrylate (a) having a number of 4 or less alkyl acrylate (a), a homopolymer having a glass transition temperature (Tg) of 80 ° C or more, and a functional group reactive with the crosslinking agent (B) In the monomer (c), the ratio of the alkyl acrylate monomer (a) having 4 or less carbon atoms to the alkyl group is 50% by weight or more based on the total amount of the monomer components, and the re-peeling adhesive composition contains foaming. And the adhesion-imparting agent, wherein the adhesion-imparting agent is an indophenol resin, the acid value of the adhesion-imparting agent is 10 KOH mg/g or less, and the dissolved component of the toluene-soluble component having a weight average molecular weight of 10,000 or less is 20% by mass. Hereinafter, the re-peeling adhesive composition is one which is heated and foamed and then peeled off. The re-adhesive composition according to claim 1, wherein the comonomer (b) having a glass transition temperature (Tg) of the homopolymer of 80 ° C or more is a monomer component constituting the acrylic copolymer (A). 1 to 20% by weight, the monomer (c) having a functional group reactive with a crosslinking agent is 0.1 to 10% by weight. The re-peeling adhesive composition according to claim 1, wherein the monomer (c) having a functional group reactive with the crosslinking agent is a carboxyl group-containing monomer, a carbonyl group-containing monomer, a hydroxyl group-containing monomer, and At least one of the glycidyl group-containing monomers. The re-peeling adhesive composition according to claim 1, wherein the comonomer (b) having a glass transition temperature (Tg) of 80 ° C or more of the above homopolymer is methyl methacrylate, acrylonitrile or (meth)acrylic acid. different At least one of ester, N,N-dimethylpropenylamine and N-propenylmorpholine. The re-adhesive composition according to claims 1 to 4, wherein the adhesion-imparting agent is a nonylphenol resin having a hydroxyl value of 70 KOH mg/g or more. A re-peelable adhesive sheet having a re-peeling adhesive layer comprising the re-peeling adhesive composition according to any one of claims 1 to 5. The peeling adhesive sheet was peeled off at 23 ° C as in claim 6, and the shearing force was 10 N / 25 mm × 25 mm or more. The re-peelable adhesive sheet according to claim 7, wherein the re-peelable adhesive sheet has a substrate, and a re-peeling adhesive layer formed of the re-peelable adhesive composition on at least one side of the substrate. The adhesive sheet is further peeled off as claimed in claim 8, wherein the re-peeling adhesive layer formed of the re-peeling adhesive composition is directly disposed on at least one side of the substrate. The adhesive sheet is further peeled off according to claim 8, wherein the recoating adhesive layer formed of the re-peeling adhesive composition is provided on at least one side of the substrate with a primer layer interposed therebetween. The adhesive sheet is peeled off further according to claim 10, wherein the thickness of the primer layer is 5 μm or less. The adhesive sheets are peeled off as in claims 6 to 11, which are used when the electronic parts are cut. The peeling of the adhesive sheet as claimed in claim 12 can be used for cutting the member for a ceramic capacitor. A method for cutting an electronic component, comprising the steps of bonding an electronic component to a re-peelable adhesive sheet according to any one of claims 6 to 11, and performing a cutting process on the electronic component.