JP5464810B2 - Peelable pressure-sensitive adhesive, peelable pressure-sensitive adhesive sheet, peeling method of peelable pressure-sensitive adhesive sheet - Google Patents

Description

  The present invention relates to an adhesive sheet for temporary surface protection such as a metal plate, a glass plate, and a plastic plate, and an adhesive sheet for processing an electronic component, and more particularly, a dicing process or a back grinding process for a semiconductor wafer or a semiconductor substrate. The present invention relates to a peelable pressure-sensitive adhesive used as a pressure-sensitive adhesive such as a pressure-sensitive adhesive sheet for fixing a semiconductor, a peelable pressure-sensitive adhesive sheet obtained thereby, and a method for peeling the peelable pressure-sensitive adhesive sheet.

In recent years, in order to prevent the occurrence of rust on the surface of metal plates, glass plates, plastic plates, etc. (in the case of metal plates), dirt and damage, adhesive sheets have been temporarily used as surface protection sheets, or semiconductor wafers Adhesive sheets are used for temporary bonding in the dicing process and back grinding process.
In addition, for semiconductor products such as glass, quartz, quartz, sapphire, and lenses, or optical related products, glass substrates on which various circuit formations or surface treatments have been applied are cut and separated (diced) into small pieces to obtain individual elements. Or it is manufactured by making parts, but in the manufacturing process, each process of the dicing process, the cleaning process, the drying process, and the pick-up process is performed in a state where the adhesive sheet is stuck on the glass substrate. It is transferred to the process. In such a glass substrate dicing process or pick-up process, there is sufficient adhesion to the cut piece from the dicing process to the drying process, and adhesion is such that the adhesive does not adhere to the cut piece in the pick-up process. A pressure-sensitive adhesive sheet is used.

  The pressure-sensitive adhesive used for these pressure-sensitive adhesive sheets has a sufficient pressure-sensitive adhesive force when affixed to an adherend, and then the pressure-sensitive adhesive strength is sufficiently reduced when cured and peeled off by ultraviolet irradiation or the like, and It is required to have a property that there is no contamination such as adhesive remaining on the adherend surface. In addition, the pressure-sensitive adhesive sheet used in the glass substrate dicing process or pick-up process has a sufficient adhesive force to the cut pieces from the dicing process to the drying process, and the pressure-sensitive adhesive adheres to the cut pieces in the pick-up process. It is desired to have such an adhesive strength that it does not.

As a pressure-sensitive adhesive used for such applications, Patent Document 1 discloses a pressure-sensitive adhesive in which an acrylic pressure-sensitive adhesive having a specific glass transition temperature and a weight average molecular weight and a radiation-curing polyfunctional liquid resin are blended at a specific ratio. In addition, a method for peeling a surface protective film is described in which the pressure-sensitive adhesive film for surface protection is irradiated with radiation to cure the pressure-sensitive adhesive, thereby peeling the film from the adherend.
Furthermore, Patent Document 2 discloses a re-peelable pressure-sensitive adhesive composition containing a functional group-containing acrylic resin, a urethane acrylate oligomer having a specific structure, a photopolymerization initiator, and a crosslinking agent. Good re-peelability, stain resistance, flexibility, etc., excellent dicing suitability for temporary bonding in the above-mentioned semiconductor wafer dicing process, and excellent elongation of cured products after UV or radiation curing It is described that the expandability is good and the curability is excellent, so that the pickup efficiency is excellent.

JP-A 62-138576 JP 2000-44893

  However, as a result of examining the above disclosed technology, the pressure-sensitive adhesive composed of the acrylic resin has a sufficient rate of decrease in the adhesive strength when comparing the adhesive strength before irradiation with the adhesive strength after radiation irradiation, In the first place, the adhesive strength with adherends such as metal plates, glass plates, and plastic plates was still insufficient when used in dicing and back grinding processes.

  Adhesion using acid-based acrylic resin (which uses acid-based monomer as a raw material monomer), which is generally known to exhibit high adhesive strength, as a method for increasing such insufficient adhesive force It is also conceivable to use agents. However, it has been found that acid-based acrylic pressure-sensitive adhesives have higher adhesive strength than non-acid-based acrylic pressure-sensitive adhesives, but corrosion may occur depending on the type of substrate and adherend. Yes. In particular, when used in a back grinding process, the problem of corrosion is very important because it is necessary to protect the circuit surface.

  Therefore, in the present invention, under such a background, the pressure-sensitive adhesive used for the application to be bonded on the assumption that the adhesive sheet once bonded and the adherend are peeled off, the adhesive before and after irradiation with active energy rays The purpose of the present invention is to provide a releasable pressure-sensitive adhesive that has a large reduction rate of force, excellent releasability, and excellent adhesion to an adherend before peeling, and does not exhibit corrosiveness to the substrate and adherend. It is what.

  However, as a result of intensive studies in view of such circumstances, the present inventor used a polyester resin instead of an acrylic resin often used as a base resin for an adhesive, and further blended an unsaturated group-containing compound. The pressure-sensitive adhesive obtained by cross-linking the resin composition with a cross-linking agent was found to have excellent releasability at the time of peeling, adhesion to an adherend, and corrosion resistance, and the present invention was completed.

That is, the gist of the present invention is that the active energy ray-curable resin composition [I] containing the polyester resin (A) and the unsaturated group-containing compound (B) is cross-linked by the cross-linking agent (C). a sexual adhesives, Ri Oh aliphatic diol starting material of the diol component of the polyester resin (a) having a hydrocarbon group in a straight chain aliphatic diol and a side chain, unsaturated group-containing compound (B) is a polyfunctional of an unsaturated group-containing compound, the amount of the unsaturated group-containing compound (B) is related to removable pressure sensitive adhesive Ru 7-100 parts by der the polyester resin (a) 100 parts by weight of.

The pressure-sensitive adhesive mainly composed of a polyester-based resin has a very small molecular weight compared to a pressure-sensitive adhesive made of an acrylic resin (acrylic pressure-sensitive adhesive: usually about 500 to 1,000,000, polyester-based pressure-sensitive adhesive: 5,000. Furthermore, compared to acrylic resins that can arbitrarily adjust the functional group concentration and introduce a large number of functional groups into one polymer, polyester resins have functional groups only at the molecular chain ends. Generally, it is difficult to introduce a functional group into the molecular chain and it is difficult to adjust the concentration of the functional group.
For this reason, when a polyester resin is used as the pressure-sensitive adhesive, there are few reactive sites with the cross-linking agent. Therefore, although cross-linking by the cross-linking agent occurs, there is a tendency that there are few molecular branches and few molecular chains are entangled. In addition, even when an unsaturated group-containing compound is contained in the pressure-sensitive adhesive and polymerized, physical interaction (formation of a network by physical crosslinking) between the polymer of the compound and the polyester resin as the main component is difficult to occur. It was thought to be.
Therefore, usually, it is difficult to consider that a pressure-sensitive adhesive made of a polyester resin is used, and it is difficult to think that a peelability equivalent to that of a pressure-sensitive adhesive made of an acrylic resin can be obtained. Adhesives based on acrylic resins have excellent peelability comparable to adhesives based on acrylic resins, and there is no problem of corrosion on the adherend, resulting in adhesive properties It was found to be excellent.

  In this invention, this peelable adhesive is provided with the peelable adhesive sheet laminated | stacked on a base material, and the peeling method of this adhesive sheet bonded with the to-be-adhered body is also provided.

  Although the peelable adhesive of the present invention has a low adhesive strength immediately after pasting so that it can be re-applied, the final ultimate adhesive strength after a certain period of time shows very high adhesive strength. It is possible to bond firmly. Furthermore, since the adhesive force is remarkably lowered by irradiating active energy rays, etc., it can be easily peeled off and is very useful. In addition, even when the adherend is a metal, it is not corrosive, and therefore has an effect that there is no fear of deteriorating the adherend.

The present invention is described in detail below.
The peelable adhesive of the present invention is obtained by crosslinking an active energy ray-curable resin composition [I] containing a polyester resin (A) and an unsaturated group-containing compound (B) with a crosslinking agent (C). It is

  The polyester-based resin (A) used in the present invention may be any polyester-based resin used for an adhesive, and includes a dicarboxylic acid component and a diol component as essential components, and a trivalent or higher polyvalent carboxylic acid component as necessary. And / or a well-known general polyester resin which consists of a polyhydric alcohol component more than trivalence can be used.

Examples of the dicarboxylic acid component in the present invention include succinic acid, methyl succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, pimelic acid, decanedicarboxylic acid, octadecanedicarboxylic acid, 1,12-dodecanoic acid, 1,14- Aliphatic acyclic dicarboxylic acids such as tetradecanoic acid and dimer acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanediacetic acid, 1,3 -Aliphatic cyclic dicarboxylic acids such as cyclohexanediacetic acid and 1,4-cyclohexanediacetic acid, aliphatics such as fumaric acid, maleic acid, itaconic acid, tetrahydrophthalic acid, tetrachlorophthalic acid, hexahydrophthalic acid and dimer acids Unsaturated dicarboxylic acid, terephthalic acid, isophthalic acid Benzene dicarboxylic acids such as orthophthalic acid, aromatic dicarboxylic acids such as 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and 4,4'-biphenyldicarboxylic acid, and acid anhydrides and lower alkyl esters thereof These can be used alone or in combination of two or more.
Among these, it is preferable to use an aromatic dicarboxylic acid or an aliphatic acyclic dicarboxylic acid. In particular, an aromatic sidicarboxylic acid and an aliphatic dicarboxylic acid are used in combination, because both durability and flexibility can be achieved. More preferably, it is particularly preferable to use isophthalic acid and sebacic acid in combination.

Examples of the diol component in the present invention include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,8-octanediol. 1,9-nonanediol, 1,10-decanediol, 1,18-octadecanediol, linear aliphatic diol such as 1,4-cyclohexanediol, neopentyl glycol, 2-methyl-1,3-propanediol 1-methyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1, 3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5 Pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3,5-trimethyl-1,3-pentanediol, 2-methyl-1,6- Hexanediol, 2-methyl-1,8-octanediol, 2-methyl-1,9-nonanediol, dimer diol, 4-methyl-1,7-heptanediol, 3-methyl-1,6-hexanediol, Aliphatic diols having a hydrocarbon group in the side chain such as 1-methyl-1,6-hexanediol, 4-methyl-1,9-nonanediol, 3-methyl-1,9-nonanediol, etc. Can be used alone or in combination of two or more.
Among these, it is necessary to use a linear aliphatic diol and an aliphatic diol having a hydrocarbon group in the side chain in view of controlling the glass transition temperature so as not to cause crystallization. At least one selected from ethylene glycol, 1,4-butanediol and 1,6-hexanediol as the aliphatic diol, and neopentyl glycol, 2-butyl-2-butyl as an aliphatic diol having a hydrocarbon group in the side chain It is particularly preferred to use at least one selected from ethyl-1,3-propanediol.

  Furthermore, as the diol component, a commercially available polyester diol component, polyether diol component, polycaprolactone diol component, polycarbonate diol component, or the like can be used in order to easily obtain a polymer having a desired molecular weight. Specifically, as the polyester diol component, for example, ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,10-decanediol, Diol components such as octadecanediol, succinic acid, methyl succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, 1,14-tetradecanedioic acid, their acid anhydrides or lower alkyl esters In a single or mixed state with a dicarboxylic acid component such as Examples of the commercially available products include polyester diols obtained by water reaction. For example, trade names “Kuraray polyol P-510”, which is a polyester diol of 3-methyl-1,5-pentanediol and adipic acid, “ Kuraray polyol P-1010 "," Kuraray polyol P-2010 "," Kuraray polyol P-3010 "," Kuraray polyol P-5010 "[manufactured by Kuraray Co., Ltd.] and the like.

  Examples of the polyether diol component include polyethylene glycol obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran and the like, polypropylene glycol, polytetramethylene glycol, and a copolyether obtained by copolymerizing these, and are commercially available products. For example, trade names “Adeka Polyether P-400”, “Adeka Polyether P-1000”, “Adeka Polyether P-2000”, “Adeka Poly”, which are polyether diols obtained by adding propylene oxide to propylene glycol. Ether P-3000 ”[manufactured by Asahi Denka Kogyo Co., Ltd.].

  Examples of the polycaprolactone diol component include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and δ-valerolactone, and commercially available products include, for example, trade name “PLAXEL L205AL”. ”,“ Placcel L212AL ”,“ Placcel L220AL ”,“ Placcel L220PL ”,“ Placcel L230AL ”[above, manufactured by Daicel Chemical Industries, Ltd.], and the like.

  Examples of the polycarbonate diol component include carbonate diols such as propylene carbonate diol, hexamethylene carbonate diol, 3-methylpentene carbonate diol, ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6- And polycarbonate diols obtained by dealcoholization reaction of polyhydric alcohols such as hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol and dialkyl carbonates such as diethylene carbonate and dimethyl carbonate. As commercial products, for example, trade names “PLACCEL CD205”, “PLACCEL CD210”, “PLACCEL CD220”, “PLACCEL CD205PL”, “P ACCEL CD210PL "," PLACCEL CD220PL "[or more, manufactured by Daicel Chemical Industries, Ltd.] and the like.

Examples of the trivalent or higher polyvalent carboxylic acid component in the present invention include aromatic polycarboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid, 1,2,4-butanetricarboxylic acid, 1,2,5, and the like. -Aliphatic polycarboxylic acids such as hexanetricarboxylic acid 1,2,4-cyclohexanetricarboxylic acid and 1,2,3,4-butanetetracarboxylic acid, and acid anhydrides and lower alkyl esters thereof. These can be used alone or in combination of two or more.
Among these, from the viewpoint of appropriately controlling the degree of dispersion, it is preferable to use a trivalent carboxylic acid, in particular, it is preferable to use a trivalent aromatic carboxylic acid, and particularly to use trimetic acid.

Examples of the trihydric or higher polyhydric alcohol component in the present invention include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 1,2, Examples thereof include aliphatic polyhydric alcohols such as 6-hexanetriol, pentaerythritol and dipentaerythritol, and these are used alone or in combination of two or more.
Among these, from the viewpoint of appropriately controlling the degree of dispersion, it is preferable to use a trivalent aliphatic alcohol, and it is particularly preferable to use trimethylolpropane.

  The polyester-based resin (A) used in the present invention has the above-mentioned dicarboxylic acid component, diol component, preferably a trivalent or higher polyvalent carboxylic acid component and / or a trivalent or higher polyhydric alcohol component as a polycondensation component. And obtained by polycondensation by a known method in the presence of a catalyst.

In the polycondensation reaction, an esterification reaction is first performed and then a condensation reaction is performed.
In such esterification reaction, a catalyst is used. Specifically, titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, antimony-based compounds such as antimony trioxide, germanium-based catalysts such as germanium oxide, zinc acetate, Examples thereof include manganese acetate and dibutyltin oxide, and one or more of these are used. Among these, antimony trioxide and tetrabutyl titanate are preferable from the viewpoint of high catalyst activity.

  The blending amount of the catalyst is preferably 1 to 10,000 ppm, more preferably 10 to 5000 ppm, and still more preferably 10 to 3000 ppm with respect to all copolymer components. If the blending amount is too small, the polymerization reaction tends not to proceed sufficiently. Conversely, if the blending amount is too large, there is no advantage such as shortening of the reaction time and a side reaction tends to occur.

  About the temperature at the time of esterification, 160-260 degreeC is preferable, 180-250 degreeC is more preferable, 200-250 degreeC is further more preferable. If the temperature is too low, the reaction tends not to proceed sufficiently, while if it is too high, side reactions such as decomposition tend to occur. Moreover, a pressure is normally implemented under a normal pressure.

  After the esterification reaction is performed, a condensation reaction is performed. The conditions at this time are such that the same amount of catalyst as in the above esterification is further added and the reaction temperature is preferably 220. It is preferable that the reaction system is gradually reduced in pressure to ˜260 ° C., more preferably 230 to 250 ° C., and the reaction is finally carried out at 5 hPa or less. If the reaction temperature is too low, the reaction tends not to proceed sufficiently, whereas if it is too high, side reactions such as decomposition tend to occur.

  A polyester resin (A) can be obtained by performing the reaction according to the above method.

  The number average molecular weight of the polyester resin (A) is preferably 5000 or more, more preferably 10,000 to 100,000, and particularly preferably 15,000 to 80,000. If the number average molecular weight is too small, sufficient cohesive force as an adhesive cannot be obtained, and heat resistance and mechanical strength tend to decrease, and if it is too large, flexibility is lost, initial adhesiveness decreases, and acupressure level There is a tendency that sufficient adhesive force cannot be exhibited at a pressure of.

  The weight average molecular weight of the polyester resin (A) is preferably 10,000 or more, particularly preferably 20,000 or more, and further preferably 50,000 or more. The upper limit is usually 500,000. If the weight average molecular weight is too small, sufficient cohesive force as a pressure-sensitive adhesive cannot be obtained, and heat resistance and mechanical strength tend to decrease. If it is too large, flexibility is lost, initial adhesiveness decreases, and finger pressure is reduced. There is a tendency that sufficient adhesive strength cannot be exhibited at a certain pressure.

The number average molecular weight and the weight average molecular weight are average molecular weights in terms of standard polystyrene molecular weight. High-performance liquid chromatography (manufactured by Nippon Waters Co., Ltd., “Waters 2695 (separation module)” and “Waters 2414 (detector)) )), Column: Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, packing material: styrene-divinylbenzene Measured using three series of polymer and filler particle size: 10 μm).

  The degree of dispersion (average molecular weight / weight number average molecular weight) of the polyester resin (A) is preferably 2 or more, more preferably 2 to 20, particularly preferably 2.2 to 10. If the degree of dispersion is too low, sufficient heat resistance tends not to be exhibited. If the degree of dispersion is too high, gelation tends to occur and the adhesive strength tends to decrease.

  The degree of dispersion depends on the content of the trihydric or higher polyhydric alcohol component and / or trihydric or higher polyhydric carboxylic acid component for constituting the polyester resin (A), and the condensation reaction conditions (temperature, degree of vacuum, Stirring, reaction time, etc.).

  The glass transition temperature of the polyester resin (A) is preferably -100 to -10 ° C, particularly preferably -80 to -15 ° C, and particularly preferably -70 to -20 ° C. If the glass transition temperature is too high, the flexibility is lost, the initial tackiness is lowered, and there is a tendency that sufficient adhesive force cannot be exerted at a pressure of a finger pressure, and if it is too low, the mechanical strength and heat resistance tend to be lowered. is there.

  The polyester resin (A) is more preferably not crystallized, and even when crystallization occurs, the crystallization temperature is preferably 0 ° C. or less, particularly preferably −30 ° C. or less, and the crystallization temperature is high. If it is too much, the tack tends to disappear. The crystallization energy is also preferably as low as possible, preferably 35 J / g or less, particularly 20 J / g or less, more preferably 15 J / g or less. If the crystallization energy is too high, tack tends to disappear. .

  In the present invention, the polyester resin (A) contains a dicarboxylic acid component, a diol component containing a glycol having a hydrocarbon group in the side chain, a trivalent or higher polyhydric alcohol and / or a trivalent or higher polyvalent. It is a polycondensation of a polyvalent carboxylic acid, and contains 0.1 to 5 mol% of a structural moiety derived from a trihydric or higher polyhydric alcohol and / or trihydric or higher polyhydric carboxylic acid. It is preferable in terms of increasing durability before UV irradiation.

  It is preferable in terms of mechanical strength and heat resistance that the dicarboxylic acid component in such a polyester resin contains an aromatic dicarboxylic acid, and it is particularly preferable to use an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid in combination. . As the aromatic dicarboxylic acid, benzine dicarboxylic acid is preferably used, and terephthalic acid and isophthalic acid are particularly preferable.

  Such a structural site derived from an aromatic dicarboxylic acid is preferably contained in the polyester-based resin in an amount of 5 to 35 mol%, more preferably 10 to 30 mol%. If the content is too small, the heat resistance and mechanical strength tend to decrease. If the content is too large, the flexibility is lost, the initial tackiness decreases, and sufficient adhesive strength tends not to be exhibited at a pressure of about a finger pressure. There is.

In such a polyester resin, the glycol-derived structural portion having a hydrocarbon group in the side chain is preferably contained in the polyester resin in an amount of 3 to 50 mol%, more preferably 5 to 40 mol%. .
When the content is too small, crystallization occurs and tack tends to disappear. When the content is too large, it tends to be difficult to obtain a high molecular weight polyester resin.

Moreover, it is preferable that 0.1-5 mol% of structural parts derived from a polyvalent carboxylic acid component having a valence of 3 or more and / or a polyhydric alcohol component having a valence of 3 or more are contained in the polyester resin. The content is particularly preferably 1 to 2.5 mol%, particularly preferably 0.2 to 2 mol%.
If the content is too small, the heat resistance tends to decrease, and if it is too large, gelation occurs and the adhesive strength tends to decrease.

In obtaining such a polyester resin, the aromatic dicarboxylic acid is preferably charged in an amount of 10 to 70 mol%, more preferably 20 to 60 mol%, based on the entire acid component.
If the amount of the aromatic dicarboxylic acid charged is too small, the heat resistance and mechanical strength tend to decrease, and if it is too large, the flexibility is lost and the initial tackiness decreases, and sufficient adhesive strength can be obtained with a pressure of about a finger pressure. There is a tendency to become unable to demonstrate.
The total acid component includes a trivalent or higher polyvalent carboxylic component when a trivalent or higher polyvalent carboxylic acid component is used.

Moreover, it is preferable to charge 5-100 mol% of glycol which has a hydrocarbon group in a side chain with respect to the whole polyhydric alcohol component, and it is still more preferable to charge 10-80 mol%. If the amount of glycol (b1) having a hydrocarbon group in the side chain is too small, crystallization occurs and tack tends to disappear.
The whole polyhydric alcohol component includes a trihydric or higher polyhydric alcohol component when a trihydric or higher polyhydric alcohol component is used.

  Furthermore, it is preferable to add 0.1 to 5 mol% of a trivalent or higher polyvalent carboxylic acid component and / or a trivalent or higher polyhydric alcohol component with respect to the total polycondensation component, and 0.2 to 2.5 More preferably, it is charged in mol%. If the amount charged is too small, the heat resistance tends to decrease, and if too large, gelation occurs and the adhesive strength tends to decrease.

  As a blending ratio of the acid component and the polyhydric alcohol component, the polyhydric alcohol component is preferably 1 to 2 equivalents, more preferably 1.2 to 1.7 equivalents per equivalent of the acid component. If the polyhydric alcohol component is too small, the acid value tends to be high and it tends to be difficult to increase the molecular weight, and if it is too large, the yield tends to decrease.

Furthermore, in the present invention, the polyester-based resin (A) is an unsaturated group-containing polyester-based resin into which an unsaturated group has been introduced, which also increases the cohesive strength of the adhesive layer after energy application and decreases the adhesive strength. Is preferable.
In that case, what is necessary is just to contain a polymerizable unsaturated group in the structure of the polyester-based resin, and preferably the one containing a polymerizable unsaturated group at the end of the main chain or the side chain of the polyester-based resin. preferable.
The polyester-based resin contains an aliphatic polyvalent carboxylic acid as an acid component and an aliphatic polyhydric alcohol as an alcohol component, and these are polycondensed. And unsaturated group containing polyester-type resin can be obtained by introduce | transducing an unsaturated group into the polyester-type resin by the method of following [1]-[4], for example.

[1] The hydroxyl group at the end of the main chain and / or the side chain of the polyester resin is reacted with the carboxyl group of the unsaturated group-containing carboxylic acid.
[2] The carboxyl group of the main chain end and / or side chain end of the polyester resin is reacted with the hydroxyl group of the unsaturated group-containing alcohol.
[3] After reacting the hydroxyl group and / or carboxyl group of the main chain end and / or side chain end of the polyester resin with a part of the isocyanate group of the polyisocyanate compound, the remaining isocyanate group and The carboxyl group of the saturated group-containing carboxylic acid or the hydroxyl group of the unsaturated group-containing alcohol is reacted.
[4] The isocyanate group of the isocyanate group-containing unsaturated compound having both an isocyanate group and an unsaturated group is reacted with the hydroxyl group and / or carboxyl group at the main chain end and / or side chain end of the polyester resin.
In addition, it is preferable that the unsaturated group of the unsaturated group-containing polyester resin (A) is a (meth) acryloyl group from the viewpoint of easy curing by ultraviolet rays.

Examples of the unsaturated group-containing compound used in the present invention (B), to increase the crosslink density of the viscosity Chakuzai, it is used polyfunctional urethane (meth) acrylate compound or a polyfunctional ethylenically unsaturated monomer In particular, it is preferable to use a compound having 3 or more unsaturated groups. In order to improve the adhesion to the substrate and the adherend, it is also preferable to use a highly polar urethane (meth) acrylate compound or an ethylenically unsaturated monomer having a polar site.

  A urethane (meth) acrylate compound is a (meth) acrylate compound having a urethane bond in the molecule, a (meth) acrylic compound containing a hydroxyl group, a polyvalent isocyanate compound, and a polyol as necessary. Can be produced by reaction. It is also possible to leave the isocyanate group consciously, make urethane acrylate having an isocyanate group and an unsaturated bond in the molecule, create a crosslinking point with the polyester resin, and have a reactive site in the adhesive main agent. This is effective for reducing the adhesive strength after irradiation.

  Examples of the (meth) acrylic compound containing a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth). Acrylate, 6-hydroxyhexyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, caprolactone modified 2-hydroxy Ethyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, caprolactone modified pen Examples include erythritol tri (meth) acrylate, ethylene oxide-modified dipentaerythritol penta (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, etc. Among them, a hydroxyl group-containing (meth) acrylic group having three or more acryloyl groups A compound is preferably used. Moreover, these can be used 1 type or in combination of 2 or more types.

  The polyvalent isocyanate compound is not particularly limited, and examples thereof include aromatic, aliphatic, and alicyclic polyisocyanates, among which tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, Polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanato) Methyl) cyclohexane, phenylene diisocyanate, lysine diisocyanate, lysine triisocyanate And polyisocyanates such as naphthalene diisocyanate or trimer compounds or multimeric compounds of these polyisocyanates, burette type polyisocyanates, water-dispersed polyisocyanates (for example, “Aquanate 100” manufactured by Nippon Polyurethane Industry Co., Ltd., ("Aquanate 110", "Aquanate 200", "Aquanate 210", etc.), or the reaction products of these polyisocyanates and polyols.

  Examples of such polyols include, but are not limited to, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, polybutylene glycol, 1,6 -Hexanediol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, polycaprolactone, trimethylolethane, trimethylolpropane, polytrimethylolpropane, pentaerythritol, polypentaerythritol, sorbitol, mannitol, glycerin, polyglycerin, poly Polyhydric alcohols such as tetramethylene glycol; polyethylene oxide, poly Polyether polyol having at least one structure of propylene oxide, ethylene oxide / propylene oxide block or random copolymerization; the polyhydric alcohol or polyether polyol and maleic anhydride, maleic acid, fumaric acid, itaconic anhydride, itacone Examples include polyester polyols that are condensates of polybasic acids such as acids, adipic acid, and isophthalic acid; caprolactone-modified polyols such as caprolactone-modified polytetramethylene polyol; polyolefin-based polyols; polybutadiene-based polyols such as hydrogenated polybutadiene polyol, and the like. .

  Furthermore, as such polyols, for example, 2,2-bis (hydroxymethyl) butyric acid, tartaric acid, 2,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxyethyl) propionic acid, 2,2-bis (hydroxypropyl) propionic acid, dihydroxymethylacetic acid, bis (4-hydroxyphenyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid Also included are carboxyl group-containing polyols such as homogentisic acid, sulfonic acid group or sulfonate group-containing polyols such as sodium 1,4-butanediol sulfonate, and the like.

  When using the reaction product of polyisocyanate and polyol, for example, it may be used as a terminal isocyanate group-containing polyisocyanate obtained by reacting the polyol with the polyisocyanate. In the reaction between the polyisocyanate and the polyol, a metal catalyst such as dibutyltin dilaurate or an amine catalyst such as 1,8-diazabicyclo [5.4.0] undecene-7 is used for the purpose of promoting the reaction. Is also preferable.

  The method for producing the urethane (meth) acrylate compound is not particularly limited. For example, a hydroxyl group-containing (meth) acrylic compound and a polyvalent isocyanate compound are mixed in an inert gas atmosphere, and usually 30 to 80 ° C., The method of making it react for 2 to 10 hours is mentioned. In this reaction, it is preferable to use a urethanization catalyst such as tin octenoate, di-n-butyltin dilaurate, lead octylate, potassium octylate, potassium acetate, stannous octoate, or triethylenediamine.

  The weight average molecular weight of the urethane (meth) acrylate compound is preferably 300 to 4000, more preferably 1000 to 3500, and particularly preferably 1200 to 3000. The method for measuring the weight average molecular weight is the same as described above.

  The bifunctional monomer may be any monomer containing two ethylenically unsaturated groups. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene oxide Modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate 1,6-hexanediol ethylene oxide modified di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) Examples include acrylate, diglycidyl phthalate di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate, and 2- (meth) acryloyloxyethyl acid phosphate diester.

  The tri- or higher functional monomer may be any monomer containing three or more ethylenically unsaturated groups. For example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) Acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, glycerin Polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ethylene oxide modified dipentaerythritol pen (Meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) acrylate, succinic acid modified pentaerythritol tri (meth) acrylate, etc. Is mentioned.

  These urethane (meth) acrylate compounds and ethylenically unsaturated monomers constituting the unsaturated group-containing compound (B) may be used alone or in combination of two or more.

The content of the unsaturated group-containing compound (B), is 7 to 100 wt parts of the polyester resin (A) 100 parts by weight of, more preferably 7-90 parts by weight, more preferably 7 to 70 weight Part. If the content is too large, the cohesive force of the pressure-sensitive adhesive layer before UV irradiation tends to be low, and the durability tends to deteriorate. If the content is too small, the pressure-sensitive adhesive strength after UV irradiation tends not to decrease much.

  These unsaturated group-containing compounds usually contain a polymerization inhibitor, but in addition to this, adding a polymerization inhibitor further increases the stability of the pressure-sensitive adhesive sheet and severe conditions such as heat-resistant applications. After use, it is preferable in that it can withstand use with a peeling process.

  The content of the added polymerization inhibitor is not limited, but is usually 20 ppm to 1%, particularly 50 ppm to 1000 ppm, based on the unsaturated group-containing compound.

  As such a polymerization inhibitor, methoxyhydroquinone or hydroquinone is preferably used.

The crosslinking agent (C) in the present invention may be a compound having a functional group that reacts with the functional group contained in the polyester resin (A). For example, bisphenol A / epichlorohydrin type epoxy resin, ethylene glycol diglycidyl Ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl Epoxy compounds such as erythritol and diglycerol polyglycidyl ether, tetramethylolmethane-tri-β-aziridinylpropionate , Trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), N, N′-hexamethylene-1,6-bis Aziridine compounds such as (1-aziridinecarboxyamide), hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexaptoxymethylmelamine, hexapentyloxymethylmelamine, hexahexyloxymethylmelamine, melamine resin, etc. Melamine compounds such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, hexamethylene diiso Anate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, and polyisocyanate compounds thereof And adducts of polyol compounds such as trimethylolpropane, isocyanate compounds such as burettes and isocyanurates of these polyisocyanate compounds, glyoxal, malondialdehyde, succindialdehyde, maleindialdehyde, glutardialdehyde, formaldehyde, Aldehyde compounds such as acetaldehyde and benzaldehyde, hexamethylenediamine, triethyldiamine, polyester Renimine, hexamethylenetetraamine, diethylenetriamine, triethyltetraamine, isophoronediamine, amino resin, amine compounds such as polyamide, aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, panadium, chromium, zirconium And metal chelate compounds such as polymetallic acetylacetone and acetoacetyl ester coordination compounds, etc. Among them, in terms of improving adhesion with a base material and reactivity with a base polymer, an isocyanate compound is used. Preferably used.
Moreover, these crosslinking agents (C) may be used independently and may be used together 2 or more types.

  The amount of the crosslinking agent (C) used can be appropriately selected depending on the amount of the functional group contained in the polyester resin (A), the molecular weight of the polyester resin (A), and the purpose of use. Usually, the polyester resin (A ) It is preferably 0.1 to 15 parts by weight, more preferably 0.2 to 12 parts by weight, and particularly preferably 0.8 to 10 parts by weight with respect to 100 parts by weight.

  If the amount of the crosslinking agent (C) is too small, the cohesive force tends to be insufficient, and sufficient durability tends not to be obtained. If the amount is too large, the flexibility before energy application tends to decrease and the adhesive strength tends to decrease. is there.

  In the peelable pressure-sensitive adhesive of the present invention, the active energy ray-curable resin composition [I] containing the polyester resin (A) and the unsaturated group-containing compound (B) is crosslinked by the crosslinking agent (C). Can be obtained. In crosslinking by such a crosslinking agent, crosslinking (chemical crosslinking) is performed by the crosslinking agent (C) reacting with the functional group of the polyester resin (A). Here, it is preferable that this active energy ray-curable resin composition [I] further contains a crosslinking agent (C) in the polyester resin (A) and the unsaturated group-containing compound (B).

  For example, after the active energy ray-curable resin composition [I] is applied to the substrate, the crosslinking is usually performed at 20 to 60 ° C., particularly 20 to 40 ° C., for 1 hour to 10 days, particularly 1 day. It is carried out by aging under the condition of ˜1 week.

  Thus, in the present invention, a releasable pressure-sensitive adhesive obtained by crosslinking the active energy ray-curable resin composition [I] with the cross-linking agent (C) is obtained. In many cases, it is applied to a base material sheet and is practically used as a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape. In order to produce such a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape, the active energy ray-curable resin composition [I] is first prepared. The concentration is adjusted as it is or with an appropriate organic solvent, and is applied to the treated surface of the substrate that has been subjected to silicon treatment or the like, or directly applied to the substrate, for example, 80 to 120 ° C., 30 seconds to 10 The peelable pressure-sensitive adhesive layer can be formed by drying by heat treatment or the like for a minute.

  The gel fraction of the pressure-sensitive adhesive layer produced by the above method is preferably in the range of 10% to 90% from the viewpoint of the balance between adhesive strength before energy application and durability, and in particular, 20 to 70% is preferred. If the gel fraction is too low, durability due to insufficient cohesive force tends to be insufficient, and if it is too high, flexibility may be lost and adhesive strength may be reduced.

In addition, the said gel fraction becomes a standard of a crosslinking degree, and is computed with the following method.
That is, an adhesive sheet (not provided with a separator) obtained as described below is wrapped in a 200 mesh SUS wire mesh, immersed in toluene at 23 ° C. for 24 hours, and the insoluble adhesive component remaining in the wire mesh The weight percentage is the gel fraction (%). However, the weight of the substrate is subtracted.

  Such a substrate is not particularly limited as long as it is a film that transmits ultraviolet rays or the like. For example, polyvinyl chloride, polybutene, polybutadiene, polyurethane, ethylene-vinyl acetate copolymer, polyethylene terephthalate, polyethylene, polypropylene, ethylene-propylene. Examples include transparent films such as copolymers, polymethylpentene, and polybutylene terephthalate. Especially when used in applications that require expansion in the dicing process of semiconductor wafers, polyvinyl chloride and polyethylene that have excellent stretchability during expansion. Colored films that are transparent or capable of transmitting ultraviolet light, such as polypropylene, ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer, are preferably used.

  In the present invention, the active energy ray-curable resin composition [I] containing the polyester resin (A) and the unsaturated group-containing compound (B) is cross-linked by the cross-linking agent (C) as an adhesive. However, when an active energy ray is irradiated there, the unsaturated group-containing compound (B) is polymerized and the pressure-sensitive adhesive is cured, and the peel strength is reduced, thereby exhibiting peelability. . In such active energy ray irradiation, the resin composition [I] preferably contains a polymerization initiator (D).

  As the polymerization initiator (D), various polymerization initiators such as a photopolymerization initiator (D1) and a thermal polymerization initiator (D2) can be used, and in particular, the photopolymerization initiator (D1). Is preferable in that it can be cured by irradiation with active energy rays such as ultraviolet rays for a very short time.

  Further, when the photopolymerization initiator (D1) is used, the sexual energy ray-curable resin composition [I] is crosslinked by irradiation with active energy rays, and when the thermal polymerization initiator is used, the active energy ray-curable type is heated. Although resin composition [I] is bridge | crosslinked, it is also preferable to use both together as needed.

  Examples of the photopolymerization initiator (D1) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4- Acetophenones such as morpholinophenyl) butanone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Ether etc. Zoins; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium Benzophenones such as chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy ) -3, -Thioxanthones such as dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Acylphosphine oxides such as phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; In addition, as for these photoinitiators (D1), only 1 type may be used independently and 2 or more types may be used together.

  These auxiliary agents include triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, 4-dimethylaminobenzoic acid. Ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone Etc. can be used in combination.

  Among these, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1- It is preferable to use phenylpropan-1-one.

  Examples of the thermal polymerization initiator (D2) include methyl ethyl ketone peroxide, cyclohexanone peroxide, methyl cyclohexanone peroxide, methyl acetoacetate peroxide, acetyl acetate peroxide, 1,1-bis (t-hexylperoxy). −3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1 -Bis (t-butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 1,1-bis (T-Butylperoxy) butane, 2,2-bis (4,4- -T-butylperoxycyclohexyl) propane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t- Butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide Oxide, octanoyl peroxide Id, lauroyl peroxide, stearoyl peroxide, succinic acid peroxide, m-toluoyl benzoyl peroxide, benzoyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butyl) (Cyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethoxyhexyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-s-butyl peroxydicarbonate, Di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α′-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethyl Rubutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypi Valate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) ) Hexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-hexyl Peroxyisopropyl monocarbonate, t-butyl peroxyisobutyrate, t-butyl Tilperoxymalate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexyl Monocarbonate, t-butylperoxyacetate, t-butylperoxy-m-toluylbenzoate, t-butylperoxybenzoate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5-bis (M-toluylperoxy) hexane, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, t-butyltrimethylsilyl peroxide, 3,3 ′, 4,4′-tetra (t-bu Organic peroxide initiators such as tilperoxycarbonyl) benzophenone and 2,3-dimethyl-2,3-diphenylbutane; 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 1-[(1 -Cyano-1-methylethyl) azo] formamide, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobisiso Butyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis (2-methyl-N-phenylpropiyl) Onamidine) dihydrochloride, 2,2′-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] dihydride chloride 2,2′-azobis [N- (4-hydrophenyl) -2-methylpropionamidine] dihydrochloride, 2,2′-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydrochloride, 2, , 2′-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2,2′-azobis [N- (2-hydroxyethyl) -2-methylpropionamidine] dihydrochloride, 2, 2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2, 2′-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (5-hydroxy-3,4,5, 6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane] dihydrochloride, 2,2 ′ -Azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide], 2,2′-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide], 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propyl Lopionamide], 2,2′-azobis (2-methylpropionamide), 2,2′-azobis (2,4,4-trimethylpentane), 2,2′-azobis (2-methylpropane), dimethyl- Initiation of azo compounds such as 2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis [2- (hydroxymethyl) propionitrile] Agents; and the like. In addition, only 1 type may be used independently for these thermal polymerization initiators, and 2 or more types may be used together.

  In the active energy ray irradiation, in addition to rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X rays and γ rays, electron beams, proton rays, neutron rays, etc. can be used. Curing by ultraviolet irradiation is advantageous from the standpoint of availability of the device and price. In addition, when performing electron beam irradiation, it can harden | cure even without using a photoinitiator (D1).

As a light source for such ultraviolet irradiation, a high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, or the like is used. In the case of a high-pressure mercury lamp, for example, it is performed under conditions of 5 to 3000 mJ / cm ² , preferably 10 to 1000 mJ / cm ² . In the case of an electrodeless lamp, it is performed under the conditions of, for example, ^{2 to} 1500 mJ / cm ² , preferably 5 to 500 mJ / cm ² . The irradiation time varies depending on the type of light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but it may be usually from several seconds to several tens of seconds, and in some cases, may be a fraction of a second. In the case of electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 Kev is used, and the irradiation amount is preferably 2 to 50 Mrad.

  Moreover, when using a thermal polymerization initiator (D2) as a polymerization initiator (D), a crosslinking reaction is started and advanced by heating.

  About content of a polymerization initiator (D), 0.01-20 weight part with respect to 100 weight part of unsaturated group containing compound (B), Especially 0.1-10 weight part, Furthermore, 1-8. It is preferable that it is a weight part. If the content is too small, the curability tends to be poor and the physical properties tend to become unstable, and if it is too much, no further effect tends to be obtained.

  As a method for preparing the peelable adhesive of the present invention, the above (A) to (C), preferably (A) to (D) may be blended (mixed), and the blending order thereof is not particularly limited. A method of blending (C) or (D) after mixing (A) and (B) in a solvent is preferred.

  The solvent used at this time is not particularly limited as long as it dissolves (A) to (D), but esters such as methyl acetate, ethyl acetate, methyl acetoacetate, ethyl acetoacetate, acetone, methylisobutyl Examples thereof include ketones such as ketones and aromatic compounds such as toluene and xylene. However, ethyl acetate is preferably used from the viewpoints of solubility, drying property, price, and the like.

  Thus, the active energy ray-curable resin composition of the present invention can be obtained. However, within the range not impairing the effects of the present invention, a polymer blend of the polyester-based pressure-sensitive adhesive (A) is carried out, or other than the above (A) Adhesives such as adhesive, urethane resin, rosin, rosin ester, hydrogenated rosin ester, phenol resin, aromatic modified terpene resin, aliphatic petroleum resin, alicyclic petroleum resin, styrene resin, xylene resin Known additives and compounds that cause coloration or discoloration by irradiation with ultraviolet rays or radiation can be blended.

The peelable pressure-sensitive adhesive of the present invention is particularly useful for temporary bonding applications in a semiconductor wafer dicing step, and such applications will be specifically described.
In this application, a semiconductor wafer (silicon wafer) is attached and fixed to an adhesive sheet or adhesive tape coated with the active energy ray-curable resin composition [I] of the present invention on a base material, and then rotated. A semiconductor wafer is cut into chips with a blade. Then, active energy rays such as electron rays, proton rays, and neutron rays as well as rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X rays and γ rays from the substrate side such as an adhesive sheet or an adhesive tape. Irradiate to cure.
As a light source for performing such active energy ray irradiation, a high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, or the like is used.
In the case of a high pressure mercury lamp, it is performed under the conditions of 5 to 3000 mJ / cm ² , preferably 10 to 1000 mJ / cm ² , more preferably 50 to 500 mJ / cm ² . In the case of an electrodeless lamp, it is performed under the conditions of, for example, ^{2 to} 1500 mJ / cm ² , preferably 5 to 500 mJ / cm ² . The irradiation time varies depending on the type of the light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but it is usually several seconds, and may be a fraction of a second in some cases. In the case of electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 Kev is used, and the irradiation amount is preferably 2 to 50 Mrad.
Such an active energy ray irradiation reduces the adhesive force and can be easily peeled off from the adherend.

Moreover, in this invention, the peelable adhesive sheet which satisfy | fills the following conditions is also provided.
The adhesive strength is measured according to the following conditions (1) and (2), and other measurement conditions are determined according to JIS Z0237 (10. Adhesive strength).

That is, the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer composed of a polyester resin (A) as a main component and measured under the following condition (2) with respect to the adhesive force (X1) measured under the following condition (1). A peelable pressure-sensitive adhesive sheet characterized in that the reduction rate Y (%) of the adhesive strength (X2) satisfies the following formula (3).
(1) SUS plate (SUS304BA mirror surface plate: thickness 0.5 mm × length 150 mm × width 70 mm) that has been mirror-treated as an adherend is coated with an adhesive sheet weighing 2 kg under an atmosphere of 23 ° C. × 50% relative humidity. After applying pressure by reciprocating twice using a roller, it was allowed to stand in an atmosphere of 60 ° C. for 24 hours, and then allowed to stand in an atmosphere of 23 ° C. × 50% relative humidity for 3 hours, followed by a peeling speed of 300 mm / min. 180 ° peel adhesive strength (N / 25 mm) is measured.
(2) A SUS plate (SUS304BA mirror plate: thickness 0.5 mm × length 150 mm × width 70 mm) mirror-treated as an adherend is coated with an adhesive sheet weighing 2 kg under an atmosphere of 23 ° C. × 50% relative humidity. Applying pressure by reciprocating twice using a roller, leaving it in an atmosphere of 60 ° C. for 24 hours, applying light and / or heat energy, and then peeling off 180 ° at a peeling speed of 300 mm / min ( N / 25 mm).
(3) 50 <Y ≦ 100
However, the decrease rate Y (%) is represented by (1- (X2 / X1)) × 100.

  Such a peelable pressure-sensitive adhesive sheet is one that reduces the pressure-sensitive adhesive strength of a pressure-sensitive adhesive containing a polyester resin by giving light and / or heat energy, and peels off. (1) A method of curing an active energy ray-curable resin composition by irradiation with active energy rays as described above to reduce adhesive strength ”,“ (2) Thermally expandable fine particles are blended in an adhesive, and thermal energy And (3) a gas contained in the microcapsule by applying thermal energy by blending a thermally expandable microcapsule in the adhesive. Method of foaming and lowering the adhesive strength "," (4) Mixing microcapsules etc. destroyed by active energy rays in the adhesive and irradiating with active energy rays The method of method "or the like to lower the adhesive strength by foaming gas contained in the microcapsules and the like can be preferably used.

The preferable range of the above-mentioned decrease rate Y is 70-100, Most preferably, it is 90-100, More preferably, it is 95-100. When the rate of decrease Y is too small, the adhesive strength at the time of peeling tends to be high, and the peelability tends to decrease. As the rate of decrease Y approaches 100, the peelability is improved and tends to be preferable.
Moreover, the polyester-type resin demonstrated above is used for this polyester-type resin (A).

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the examples, “parts” and “%” mean weight basis unless otherwise specified.

[Production of polyester resin (A-1)]
In a four-necked separable flask equipped with a thermometer, a stirrer, a distillation tube and a condenser, neopentyl glycol 108.4 g (0.9 mol), 1,4-butanediol 52 g (0.5 mol), 1, 6-hexanediol 12 g (0.087 mol), trimethylolpropane 2.0 g (0.013 mol), isophthalic acid 38.4 g (0.2 mol), sebacic acid 187.2 g (0.8 mol) and tetra 0.18 g of butyl titanate is charged and heated at 150 to 260 ° C. for 210 minutes to carry out an esterification reaction, then the pressure of the reaction system is gradually decreased to 133 Pa after 30 minutes, and further reacted for 270 minutes while continuing to reduce the pressure. It was. Various physical properties of the obtained polyester resin are as shown in Table 1.

[Production of polyester-based resin (A-2)]
In a four-neck separable flask equipped with a thermometer, a stirrer, a distillation tube, and a condenser, neopentyl glycol 86.4 g (0.7 mol), 1,4-butanediol 53.2 g (0.5 mol), 1,6-hexanediol 40 g (0.287 mol), trimethylolpropane 2.0 g (0.013 mol), isophthalic acid 98.4 g (0.5 mol), sebacic acid 119.6 g (0.5 mol) Then, 0.18 g of tetrabutyl titanate was added, and the esterification reaction was carried out by heating at 150 to 260 ° C. for 210 minutes, and then the pressure of the reaction system was gradually reduced to 133 Pa after 30 minutes, and the reaction was continued for 270 minutes while continuing to reduce the pressure. Went. Various physical properties of the obtained polyester resin are as shown in Table 1.

  The physical properties of the polyester resins (A-1) and (A-2) were measured and summarized in [Table 1] below.

  In addition, the measuring method of each physical property is as follows.

<Weight average molecular weight, number average molecular weight>
The weight average molecular weight and the number average molecular weight are average molecular weights in terms of standard polystyrene molecular weight, and are used in high performance liquid chromatography (manufactured by Nippon Waters Co., Ltd., “Waters 2695 (Separation Module)” and “Waters 2414 (Detector)”). Column: Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / pack, filler material: styrene-divinylbenzene copolymer, The particle size was measured by using three filler particles having a particle diameter of 10 μm.

<Dispersity>
It was calculated from the weight average molecular weight and the number average molecular weight.

<Glass transition temperature>
The test piece is heated and cooled from room temperature at a rate of 10 ° C./min, the calorific value is measured with a differential scanning calorimeter, two extension lines are drawn on the endothermic curve or exothermic curve, and 1 between the extension lines. The temperature at the intersection of the / 2 line and the endothermic curve or exothermic curve was taken as the glass transition temperature.

<Crystalization temperature>
The test piece was heated and cooled from room temperature at a rate of 10 ° C./min, the calorific value was measured with a differential scanning calorimeter, and the top of the exothermic peak was taken as the crystallization temperature.

<Crystalization energy>
The test piece was heated and cooled from room temperature at a rate of 10 ° C./min, and the calorific value was measured with a differential scanning calorimeter, and was determined from the exothermic peak.

[Production of Acrylic Resin (A-1)]
A 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer was charged with 140 parts of ethyl acetate, and 0.03 part of azobisisobutyronitrile (AIBN) as a polymerization initiator. The mixture was heated with stirring, and at 78 ° C., a mixture of 95 parts of butyl acrylate and 5 parts of acrylic acid was added dropwise over 2 hours. While adding polymerization initiator solution in which 0.03 part of AIBN was dissolved in 10 parts of ethyl acetate during the polymerization, the mixture was polymerized at ethyl acetate reflux temperature for 5 hours and then diluted to obtain an acrylic resin solution (A-1). (Weight average molecular weight (Mw) 600,000, solid content 40%, viscosity 10,000 mPa · s (25 ° C.)) was obtained.

[Manufacture of acrylic resin (A-2)]
A 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer was charged with 140 parts of ethyl acetate, and 0.03 part of azobisisobutyronitrile (AIBN) as a polymerization initiator. The mixture was heated with stirring, and a mixture of 95 parts of butyl acrylate and 5 parts of 2-hydroxyethyl acrylate was added dropwise at 78 ° C. over 2 hours. While adding polymerization initiator solution in which 0.03 part of AIBN was dissolved in 10 parts of ethyl acetate during the polymerization, the mixture was polymerized at ethyl acetate reflux temperature for 5 hours, and then diluted to obtain an acrylic resin solution (A-2). (Weight average molecular weight (Mw) 600,000, solid content 40%, viscosity 10,000 mPa · s (25 ° C.)) was obtained.

[Production of unsaturated group-containing compound (B-1)]
In a four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 6.6 parts of isophorone diisocyanate (IPDI), 93.4 parts of dipentaerythritol pentaacrylate, di-t- 0.03 part of butylhydroxyphenol and 0.02 part of dibutyltin dilaurate were charged, and the reaction was continued at 50 ° C. to obtain an unsaturated group-containing compound (B-1). The weight average molecular weight of the unsaturated group-containing compound (B-1) was 1500.

[Production of unsaturated group-containing compound (B-2)]
In a four-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 19.2 parts of isophorone diisocyanate (IPDI), 0.05 part of di-t-butylhydroxyphenol, dibutyltin dilaurate 0.02 part was charged, and at 50 ° C. or less, 80.8 parts of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (Kyoeisha Chemical Co., Ltd., Light Acrylate PE-3A, hydroxyl value 120 mgKOH / g) at 70 ° C. The reaction was continued to obtain an unsaturated group-containing compound (B-2). The weight average molecular weight of the unsaturated group-containing compound (B-2) was 3,500.

[Crosslinking agent (C)]
The following were prepared as a crosslinking agent (C-1).
-50% butyl acetate solution of tolylene diisocyanate trimer (manufactured by Nippon Polyurethane, “Coronate 2030”)
The following were prepared as a crosslinking agent (C-2).
・ 55% ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct (manufactured by Nippon Polyurethane Co., Ltd., “Coronate L-55E”)

[Polymerization initiator (D)]
The following were prepared as the photopolymerization initiator (D-1).
1-hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by Ciba Specialty Chemicals)

Examples 1-6, Comparative Examples 1-4
As shown in [Table 2], a resin composition diluted to a viscosity (1000-5000 mPa · s / 25 ° C.) that can be applied with ethyl acetate was prepared. Using this resin composition, an adhesive sheet with a peelable adhesive was produced by the following method.

[Preparation of adhesive sheet with peelable adhesive]
After preparing a polyethylene terephthalate (PET) film (thickness 38 μm) as a base material and applying the pressure-sensitive adhesive composition to the PET film surface to a thickness of 25 μm after drying on the surface of the PET film in a state where ultraviolet rays are blocked. And dried at 100 ° C. for 2 minutes. Thereafter, a release-treated PET film was attached to the surface of the pressure-sensitive adhesive composition for protection to obtain a pressure-sensitive adhesive sheet with a peelable pressure-sensitive adhesive.

  The adhesive sheets of Examples and Comparative Examples thus obtained were cured at 40 ° C. for 4 days, and then various physical properties were evaluated according to the following methods. The results are shown in [Table 3]. The release-treated PET sheet was peeled off when performing various measurement tests.

<Achieved adhesive strength>
In a 23 ° C. × 50% relative humidity atmosphere, a mirror-treated SUS plate (SUS304BA mirror plate: thickness 0.5 mm × length 150 mm × width 70 mm) is placed on a 2 kg weight roller. After being used and pressed twice by reciprocating in 40 seconds, it was left in an atmosphere at 60 ° C. for 24 hours. Subsequently, after being left for 3 hours in an atmosphere of 23 ° C. × 50% relative humidity, 180 ° peeling strength (N / 25 mm) was measured at a peeling speed of 300 mm / min. Such 180 ° peeling adhesive force is defined as ultimate adhesive force (X1).

<Adhesive strength after UV irradiation>
In a 23 ° C. × 50% relative humidity atmosphere, a mirror-treated SUS plate (SUS304BA mirror plate: thickness 0.5 mm × length 150 mm × width 70 mm) is placed on a 2 kg weight roller. After being used and pressed twice by reciprocating in 40 seconds, it was left in an atmosphere at 60 ° C. for 24 hours. Next, ultraviolet irradiation (high-pressure mercury lamp lamp 80W, 1 lamp is used and ultraviolet irradiation of 2 passes (accumulated irradiation amount 420 mJ / cm ² ) is performed at a conveyor speed of 4.6 m / min from a height of 18 cm) at 23 ° C. X After standing for 3 hours in an atmosphere with a relative humidity of 50%, the adhesive strength (N / 25 mm) was measured by peeling 180 ° at a peeling speed of 300 mm / min. The 180 ° peeling adhesive strength is defined as an adhesive strength after UV irradiation (X2).

<Adhesion reduction rate after UV irradiation>
The value calculated by the formula: (1- (X2 / X1)) × 100 was defined as the adhesive strength reduction rate after UV irradiation (Y (%)).

<Metal corrosion resistance>
The adhesive sheet is attached to a copper plate, left in a dark room at 60 ° C. × 90% relative humidity for 1 week, then left at 23 ° C. and 50% relative humidity for 1 hour, irradiated with ultraviolet rays, The pressure-sensitive adhesive sheet was peeled, and the peeled surface of the copper plate was visually compared with a blank copper plate and evaluated as follows.
○: It does not replace the blank copper plate surface.
X: The copper plate surface discolors and corrosion is recognized.

From the above results, the pressure-sensitive adhesive sheets of Examples 1 to 6 composed of pressure-sensitive adhesives using the polyester resins (A-1) and (A-2) exhibit sufficiently strong adhesive strength in about 24 hours after being attached. Further, it can be seen that the adhesive strength is sufficiently lowered after UV irradiation, it can be easily peeled off, and it has excellent metal corrosion resistance.
On the other hand, both of the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2 composed of pressure-sensitive adhesives using acrylic resins (A-1) and (A-2) have sufficient reduction in adhesive strength after UV irradiation. Comparative Example 1 using an acid acrylic resin shows corrosivity to metals, and Comparative Example 2 using a non-acid acrylic resin does not show corrosivity, but has low adhesive strength. It can be seen that stable adhesion at the time of fixation is difficult.
Further, in the pressure-sensitive adhesive sheets of Comparative Examples 3 and 4 using a pressure-sensitive adhesive made of a polyester resin not containing an unsaturated group-containing compound, the pressure-sensitive adhesive force does not decrease due to UV irradiation, and the peelable pressure-sensitive adhesive is premised on peeling. It turns out that it cannot be used for a use.
As described above, the peelable pressure-sensitive adhesive of the present invention has a large decrease rate of the adhesive strength before and after irradiation with active energy rays, and is excellent not only in peelability but also with the adherend before irradiation with active energy rays. It is a very useful peelable adhesive that is excellent in strength, can be easily peeled off after irradiation, and does not show corrosive properties to the substrate and adherend.

The peelable adhesive of the present invention exhibits strong adhesive strength while being corrosion resistant, and has a very low adhesive strength when peeled off, so it can be firmly fixed when fixed and easily peeled off when peeled Therefore, it can also be used for adherends that are prone to corrosion.
Therefore, it is very useful as a peelable pressure-sensitive adhesive used for metal plates, glass plates, synthetic resin plates, laminated steel plates, etc. for labels and sheets, for tapes, for building materials, for packaging materials, and for electronics.

Claims (7)

An active energy ray-curable resin composition [I] containing a polyester resin (A) and an unsaturated group-containing compound (B) is a peelable pressure-sensitive adhesive formed by crosslinking with a crosslinking agent (C). Ri raw material diol component of the resin (a) is Ah aliphatic diol having a hydrocarbon group in a straight chain aliphatic diol and a side chain, unsaturated group-containing compound (B) is be unsaturated group-containing compound of the polyfunctional , removable pressure sensitive adhesive, wherein 7-100 parts by der Rukoto amount is the polyester resin (a) 100 parts by weight of an unsaturated group-containing compound (B).   The peelable pressure-sensitive adhesive according to claim 1, wherein the polyester resin (A) has a glass transition temperature (Tg) of -100 to -10 ° C.   The peelable pressure-sensitive adhesive according to claim 1 or 2, wherein the unsaturated group-containing compound (B) is a compound having 3 or more unsaturated groups. The peelable adhesive according to any one of claims 1 to 3 , wherein the amount of the crosslinking agent (C) used is 0.1 to 20 parts by weight with respect to 100 parts by weight of the polyester resin (A). . The active energy ray-curable resin composition [I] further contains a polymerization initiator (D), the peelable adhesive according to any one of claims 1 to 4 . Peelable adhesive sheet peelable pressure-sensitive adhesive in accordance with claim 1-5, characterized in that the formed by stacking on a substrate. A method for peeling a peelable pressure-sensitive adhesive sheet, comprising: bonding the peelable pressure-sensitive adhesive sheet according to claim 6 to an adherend, and then peeling the pressure-sensitive adhesive sheet and the adherend by irradiating active energy rays. .