Active energy ray-curable peelable pressure-sensitive adhesive composition

Abstract

The present invention addresses the problem of providing an active energy ray-curable peelable pressure-sensitive adhesive composition which has a high biomass-derived carbon content ratio (bio-based carbon content ratio), does not cause an adhesive residue to remain when peeled from an adherend, and is suitable for use in dicing tape. The means for solving the problem is an active energy ray-curable peelable pressure-sensitive adhesive composition comprising a photopolymerization initiator, a crosslinking agent, and an acrylic pressure-sensitive adhesive polymer having an active energy ray-reactive carbon-carbon double bond, wherein the acrylic pressure-sensitive adhesive polymer is a polymer having the active energy ray-reactive carbon-carbon double bond in a side chain of a (meth)acrylic acid ester-based copolymer; the (meth)acrylic acid ester-based copolymer contains, as constitutional units of the copolymer, a constitutional unit derived from a (meth)acrylic acid alkyl ester having a biomass-derived alkyl group at an ester terminal and a constitutional unit derived from a monomer having a functional group; the glass transition temperature (Tg) is -18°C or lower; and a bio-based carbon content ratio of the acrylic pressure-sensitive adhesive polymer is 50% by mass or more.

Description

Active energy ray curable release adhesive composition

[0001] The present invention relates to an active energy ray-curable release adhesive composition, and an active energy ray-curable release adhesive composition that can be used in adhesive tapes for semiconductor processing.

[0002] Dicing tapes used in the dicing process of semiconductor device manufacturing have a structure in which an adhesive layer is provided on a base film, and are used to fix and hold semiconductor chips that have been separated by dicing during the dicing of semiconductor wafers or packages, preventing them from scattering. The separated semiconductor chips are then peeled off from the adhesive layer of the dicing tape. The adhesive layer of the dicing tape is required to have sufficient adhesive strength to fix and hold the separated semiconductor chips in place during dicing, while at the same time, it is required that the adhesive strength be reduced during the subsequent pick-up process when the separated semiconductor chips are peeled off from the adhesive layer of the dicing tape, so as not to damage the semiconductor chips.

[0003] In recent years, due to growing environmental awareness, there has been a shift in the use of materials in such adhesive layers from conventional petroleum-derived raw materials to biomass-derived raw materials.

[0004] Patent Document 1 discloses an adhesive composition comprising an adhesive, wherein the adhesive is an acrylic adhesive comprising an acrylic polymer, the acrylic polymer is a polymer of a monomer component containing more than 50% by weight of an acrylic monomer, more than 50% of the total carbon contained in the adhesive is biomass-derived carbon, the monomer component comprises an alkyl (meth)acrylate having a biomass-derived alkyl group having 12 or more carbon atoms at its ester end, the monomer component comprises 30% by weight or more of an alkyl (meth)acrylate having a biomass-derived alkyl group having 16 or more carbon atoms at its ester end, at least a portion of the alkyl (meth)acrylate having a biomass-derived alkyl group having 12 or more carbon atoms at its ester end is a branched alkyl (meth)acrylate having a biomass-derived branched alkyl group having 12 or more carbon atoms at its ester end, and the monomer component comprises two or more types of alkyl (meth)acrylates having different biomass-derived alkyl groups having 12 or more carbon atoms.

[0005] Patent Document 2 describes an active energy ray-curable release adhesive composition that contains an acrylic resin (A) and a urethane (meth)acrylate (B), wherein the acrylic resin (A) is derived from a biological raw material and contains an alkyl (meth)acrylate (a1-BIO) having an alkyl group with 8 to 24 carbon atoms as a constituent unit (α), and the urethane (meth)acrylate (B) contains a polyvalent isocyanate compound (b2-BIO) containing carbon derived from a biological raw material and / or a polyol compound (b3-BIO) containing carbon derived from a biological raw material as a constituent unit (β).

[0006] Japanese Patent Publication No. 7386609, Japanese Unexamined Patent Publication No. 2024-064172

[0007] However, the adhesive composition disclosed in Patent Document 1 is an adhesive composition mainly used for fixing or joining members, and is not an active energy ray curable release-type adhesive composition having a function of reducing the adhesive force by irradiation with active energy rays. Therefore, for example, it is not suitable for use as a dicing tape for dicing a semiconductor wafer and picking up the diced semiconductor chips. In addition, when an alkyl (meth) acrylate having a biomass-derived alkyl group with an excessively large number of carbon atoms at the ester terminal is used as the main component of the copolymer, the copolymerization reaction becomes difficult to proceed smoothly, and it may be difficult to obtain a polymer with a high molecular weight.

[0008] Also, in an adhesive composition containing both an acrylic resin that is not curable by active energy rays and an urethane (meth) acrylate-based oligomer that is curable by active energy rays as in Patent Document 2, depending on the compatibility of the oligomer with the acrylic resin, the molecular weight and the addition amount of the oligomer, there is a risk that the adhesive characteristics may not be stable, and there is a risk that adhesive residue may occur when peeling from an adherend such as a semiconductor wafer, leaving room for improvement.

[0009] Therefore, an aspect of the present invention is to provide an active energy ray curable release-type adhesive composition suitable for use as a dicing tape, which has a high biomass-derived carbon content ratio (bio-based carbon content rate) and does not cause adhesive residue when peeling from an adherend.

[0010] The present invention includes the following aspects.

[0011] [Form 1] An active energy ray-curable release-type adhesive composition containing an acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond, a photoinitiator, and a crosslinking agent, wherein the acrylic adhesive polymer is a polymer having an active energy ray-reactive carbon-carbon double bond in the side chain of a (meth)acrylic acid ester copolymer, the (meth)acrylic acid ester copolymer contains, as a constituent unit of the copolymer, a constituent unit derived from a (meth)acrylic acid alkyl ester having a biomass-derived alkyl group at the ester terminal and a constituent unit derived from a monomer having a functional group, and the glass transition temperature (Tg) is -18°C or lower, preferably in the range of -50°C or higher to -18°C or lower, -45°C or higher to -25°C or lower, -40°C or higher to -30°C or lower, or -40°C or higher to -18°C or lower, and the bio-based carbon content of the acrylic adhesive polymer is 50% by mass or higher, preferably in the range of 50% by mass or higher to 72% by mass or lower, 51% by mass or higher to 70% by mass or lower, 52% by mass or higher to 65% by mass or lower, or 52% by mass or higher to 60% by mass or lower.

[0012] [Form 2] The active energy ray-curable release-type adhesive composition according to Form 1, wherein the (meth)acrylic acid alkyl ester having a biomass-derived alkyl group at the ester terminal contains a (meth)acrylic acid alkyl ester having a biomass-derived alkyl group having 4 or more and 12 or less carbon atoms, preferably 4 or more and 8 or less carbon atoms, more preferably 6 or more and 8 or less carbon atoms, at the ester terminal.

[0013] [Form 3] The active energy ray-curable release-type adhesive composition according to Form 2, wherein the (meth)acrylic acid alkyl ester having a biomass-derived alkyl group at the ester terminal further contains a (meth)acrylic acid alkyl ester having a biomass-derived alkyl group having 14 or more and 18 or less carbon atoms at the ester terminal.

[0014] [Form 4] The active energy ray curable peelable adhesive composition according to Form 2, wherein the content of constituent units derived from (meth)acrylate alkyl esters having a biomass-derived alkyl group having 4 to 12 carbon atoms at the ester terminus is in the range of 65.0% to 93.9% by mass, preferably 70.0% to 89.7% by mass, or 78.0% to 84.5% by mass, relative to the total constituent units contained in the (meth)acrylate ester copolymer, and the content of constituent units derived from monomers having the functional group is in the range of 6.1% to 35.0% by mass, preferably 10.3% to 30.0% by mass, more preferably 15.5% to 22.0% by mass, relative to the total constituent units contained in the (meth)acrylate ester copolymer.

[0015] [Form 5] The content of constituent units derived from alkyl (meth)acrylate esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus is in the range of 36.9% by mass or more and 93.8% by mass or less, preferably 45.5% by mass or more and 88.7% by mass or less, or 58.0% by mass or more and 79.5% by mass or less, relative to the total constituent units contained in the (meth)acrylate ester copolymer, and the content of constituent units derived from alkyl (meth)acrylate esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus is The active energy ray curable peelable adhesive composition according to Embodiment 3, wherein the amount of the functional group is in the range of 0.1% to 30.0% by mass, preferably 1.0% to 25.0% by mass, or 5.0% to 20.0% by mass, relative to the total structural units contained in the ster-based copolymer, and the content of structural units derived from the monomer having the functional group is in the range of 6.1% to 33.1% by mass, preferably 10.3% to 29.5% by mass, more preferably 15.5% to 22.0% by mass, relative to the total structural units contained in the (meth)acrylic acid ester copolymer.

[0016] [Form 6] The active energy ray curable release adhesive composition according to any one of Forms 1 to 5, wherein the monomer having the functional group comprises a hydroxyl group-containing monomer and a carboxyl group-containing monomer.

[0017] [Form 7] The monomer having the functional group is a hydroxyl group-containing monomer and a carboxyl group-containing monomer, the content of the constituent units derived from the hydroxyl group-containing monomer is in the range of 6.0% by mass or more and 30.0% by mass or less, preferably 10.0% by mass or more and 27.0% by mass or less, more preferably 15.0% by mass or more and 20.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer, and the content of the constituent units derived from the carboxyl group-containing monomer is in the range of 0.1% by mass or more and 5.0% by mass or less, preferably 0.3% by mass or more and 3.0% by mass or less, more preferably 0.5% by mass or more and 2.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer, the active energy ray-curable peelable adhesive composition according to Form 4.

[0018] [Form 8] The monomer having a functional group is a hydroxyl group-containing monomer and a carboxyl group-containing monomer, the content of constituent units derived from the hydroxyl group-containing monomer is in the range of 6.0% by mass or more and 30.0% by mass or less, preferably 10.0% by mass or more and 27.0% by mass or less, more preferably 15.0% by mass or more and 20.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer, and the content of constituent units derived from the carboxyl group-containing monomer is in the range of 0.1% by mass or more and 3.1% by mass or less, preferably 0.3% by mass or more and 2.5% by mass or less, more preferably 0.5% by mass or more and 2.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer, the active energy ray-curable peelable adhesive composition according to Form 5.

[0019] [Form 9] The active energy ray curable release adhesive composition according to any one of Forms 2 to 8, wherein the alkyl (meth)acrylate ester having a biomass-derived alkyl group having 4 to 12 carbon atoms at its ester terminus is an alkyl (meth)acrylate ester having a biomass-derived alkyl group having 4 to 8 carbon atoms at its ester terminus.

[0020] [Form 10] The active energy ray-curable peelable adhesive composition according to any one of Forms 1 to 9, wherein the acrylic adhesive polymer has an active energy ray-reactive carbon-carbon double bond concentration in the range of 0.30 mmol / g or more and 1.30 mmol / g or less, preferably 0.40 mmol / g or more and 1.10 mmol / g or less, and more preferably 0.55 mmol / g or more and 0.95 mmol / g or less.

[0021] [Form 11] The active energy ray-curable release adhesive composition according to any one of Forms 1 to 10, wherein the content of the acrylic adhesive polymer is 85% by mass or more, in terms of solid content, in the range of 85.00% by mass or more and less than 100.00% by mass, preferably 94.00% by mass or more and 99.50% by mass or less, more preferably 97.50% by mass or more and 99.00% by mass or less, and particularly preferably 98.00% by mass or more and 98.50% by mass or less, based on solid content.

[0022] [Form 12] An adhesive tape for semiconductor processing comprising an adhesive layer containing a crosslinked material of the active energy ray curable peelable adhesive composition described in any of Forms 1 to 11.

[0023] [Form 13] The adhesive layer of the semiconductor processing adhesive tape is prepared after ultraviolet irradiation of a SUS304BA plate at 23°C (integrated ultraviolet light intensity: 300 mJ / cm²). ２ The semiconductor processing adhesive tape according to Embodiment 12, wherein the adhesive strength at a peeling angle of 90 degrees and a peeling speed of 5 mm / sec is in the range of 0.01 N / 10 mm to 0.45 N / 10 mm, preferably in the range of 0.02 N / 10 mm to 0.35 N / 10 mm, 0.03 N / 10 mm to 0.25 N / 10 mm, and more preferably in the range of 0.01 N / 10 mm to 0.10 N / 10 mm.

[0024] [Form 14] An article manufactured using the active energy ray curable release adhesive composition or a crosslinked product thereof described in any of Forms 1 to 11.

[0025] According to one aspect of the present invention, it is possible to provide an active energy ray-curable release adhesive composition suitable for dicing tape applications, which has a high biomass-derived carbon content (bio-based carbon content) and does not leave any adhesive residue when peeled off from the adherend.

[0026] Embodiments of the present invention will be described in detail below. However, the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the invention. The upper and lower limits of the numerical ranges described herein can be arbitrarily selected and combined from the numerical values ​​exemplified as numerical ranges to create a suitable numerical range.

[0027] [Active Energy Ray Curable Release Adhesive Composition] The active energy ray curable release adhesive composition (hereinafter also simply referred to as "adhesive composition") comprises an acrylic adhesive polymer having an active energy ray reactive carbon-carbon double bond (hereinafter also simply referred to as "acrylic adhesive polymer"), a photopolymerization initiator, and a crosslinking agent. In this specification, the active energy ray curable release adhesive composition means an adhesive composition that hardens and shrinks upon irradiation with active energy rays, thereby reducing its adhesive strength to the adherend. Examples of active energy rays include ultraviolet rays (UV), visible light, infrared rays, electron beams (EB), beta rays, gamma rays, etc. Among these active energy rays, ultraviolet rays and electron beams are preferred, and ultraviolet rays are particularly preferred. The content of the acrylic adhesive polymer in the total mass of the active energy ray curable release adhesive composition is preferably 85% by mass or more, and more preferably 94% by mass or more. The adhesive composition of the present invention may contain only one type of acrylic adhesive polymer of the present invention, or it may contain two or more types.

[0028] <Acrylic Adhesive Polymer> The acrylic adhesive polymer in the present invention is a polymer based on a (meth)acrylic acid ester copolymer. The acrylic adhesive polymer in the present invention is a polymer having an active energy ray-reactive carbon-carbon double bond in the side chain of its base polymer, the (meth)acrylic acid ester copolymer. The (meth)acrylic acid ester copolymer contains, as constituent units of the copolymer, constituent units derived from a biomass-derived alkyl group at the ester terminus of an alkyl (meth)acrylate (hereinafter also simply referred to as "biomass (meth)acrylate alkyl ester") and constituent units derived from a monomer having a functional group, and has a glass transition temperature (Tg) of -18°C or lower, and the bio-based carbon content of the acrylic adhesive polymer is 50% by mass or more.

[0029] In this specification, "(meth)acrylic" refers to the general term for acrylic and methacrylic, and can represent one or both of them. Furthermore, (meth)acrylic acid ester copolymers having an active energy ray-reactive carbon-carbon double bond in their side chains (hereinafter also simply referred to as "copolymers") can be obtained by reacting (e.g., addition reaction, condensation reaction) a "compound having a functional group and a carbon-carbon double bond (active energy ray-reactive compound)" that can undergo addition or condensation reactions with the functional group of the "(meth)acrylic acid ester copolymer," which is the base polymer of the acrylic adhesive polymer. In this specification, "glass transition temperature (Tg) of the (meth)acrylic acid ester copolymer" refers to the glass transition temperature (Tg) of the "(meth)acrylic acid ester copolymer," which is the base polymer before the active energy ray-reactive carbon-carbon double bond is introduced by the above addition or condensation reaction.

[0030] The above-mentioned acrylic adhesive polymer is a polymer having an active energy ray-reactive carbon-carbon double bond in the side chain of its base polymer, a (meth)acrylic acid ester copolymer. Therefore, when an adhesive composition containing the acrylic adhesive polymer is used as the adhesive layer of an adhesive tape, an adherend can be attached to the adhesive layer, and after the adherend has been processed as desired, the adherend can be easily peeled off the adhesive layer of the adhesive tape by irradiation with active energy rays. Because the above-mentioned acrylic adhesive polymer has an active energy ray-reactive carbon-carbon double bond, there is no need to include low molecular weight components such as oligomers having an active energy ray-reactive carbon-carbon double bond in the adhesive composition, thus significantly reducing adhesive residue on the adherend after peeling. Therefore, the above-mentioned acrylic adhesive polymer can be suitably used, for example, as an adhesive polymer in the adhesive composition of adhesive tapes for semiconductor processing.

[0031] Furthermore, since the above-mentioned acrylic adhesive polymer has a bio-based carbon content of 50% by mass or more, its dependence on fossil fuel-based materials can be moderately suppressed. The higher the bio-based carbon content, the more highly the dependence on fossil fuel-based materials can be suppressed. The bio-based carbon content of the above-mentioned acrylic adhesive polymer, that is, the proportion of biomass-derived carbon in the total carbon contained in the acrylic adhesive polymer, can be calculated from the carbon isotope content with mass number 14, measured in accordance with ASTM D6866. Here, biomass-derived carbon means carbon derived from biomass materials, that is, materials derived from renewable organic resources (renewable carbon). The above-mentioned biomass materials typically refer to materials derived from biological resources (typically photosynthetic plants) that can be sustainably reproduced if sunlight, water, and carbon dioxide are present. Therefore, materials derived from fossil resources that are depleted by use after mining (fossil fuel-based materials) are excluded from the concept of biomass materials as used here.

[0032] Furthermore, since the glass transition temperature (Tg) of the (meth)acrylic acid ester copolymer, which is the base polymer of the acrylic adhesive polymer, is -18°C or lower, the adhesive layer made from the adhesive composition containing the acrylic adhesive polymer has appropriate adhesive strength to the adherend. Here, in this specification, the glass transition temperature (Tg) of the (meth)acrylic acid ester copolymer refers to the Tg determined by Fox's formula based on the composition of the monomer components used in the preparation of the polymer. Fox's formula is a relationship between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below.

[0033] 1 / Tg=Σ(Wi / Tgi)

[0034] In the above Fox equation, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction of monomer i in the copolymer (weight-based copolymerization ratio), and Tgi represents the glass transition temperature of the monomer i homopolymer (unit: K). When the polymer for which Tg is to be specified is a homopolymer, the Tg of the homopolymer and the Tg of the polymer in question are the same.

[0035] The glass transition temperature of the homopolymer used in calculating Tg shall be the value specified in publicly available documents. Specifically, the values ​​are given in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989).

[0036] The (meth)acrylic acid ester copolymer, which is the base polymer of the acrylic adhesive polymer of the present invention, mainly contains constituent units derived from (meth)acrylic acid alkyl esters having a biomass-derived alkyl group at the ester terminus. Here, a main constituent unit refers to a constituent unit that accounts for more than 50% by mass of the total constituent units of the copolymer. In other words, the (meth)acrylic acid ester copolymer used as the base polymer of the acrylic adhesive polymer of the present invention is a copolymer of monomers in which (meth)acrylic acid alkyl esters having a biomass-derived alkyl group at the ester terminus (biomass (meth)acrylic acid alkyl esters) are contained in proportion to more than 50% by mass of the total copolymer monomer components as part of the copolymer monomer composition.

[0037] The alkyl (meth)acrylate esters having the biomass-derived alkyl group at the ester terminus are not particularly limited, but examples include esters of biomass-derived alkanol and biomass-derived or non-biomass-derived (meth)acrylic acid. In some embodiments, esters of biomass-derived alkanol and non-biomass-derived (meth)acrylic acid are used as biomass (meth)acrylate alkyl esters used in the synthesis of (meth)acrylic acid ester copolymers that serve as the base polymer for acrylic adhesive polymers. In such biomass (meth)acrylate alkyl esters, the more carbon atoms the alkanol has, the higher the proportion of biomass-derived carbon to the total number of carbon atoms in the biomass (meth)acrylate ester, i.e., the higher the bio-based carbon content of the (meth)acrylate alkyl ester. Therefore, in the above alkyl (meth)acrylate esters, a large number of carbon atoms in the biomass-derived alkyl group is desirable in terms of reducing dependence on fossil fuel-based materials. On the other hand, if the number of carbon atoms in the alkyl group constituting the (meth)acrylate alkyl ester is too high, it tends to be difficult to obtain good adhesive properties, and it can also be disadvantageous in terms of productivity such as synthesis, handling, and cost. In embodiments in which the biomass (meth)acrylate alkyl ester is used as described above, an ester of biomass-derived alkanol and non-biomass-derived (meth)acrylic acid, it is preferable to use a material that balances good adhesive properties (for example, a desired Tg of the copolymer as an indicator) and reduced dependence on fossil resource-based materials (for example, a desired bio-based carbon content of the acrylic adhesive polymer as an indicator).

[0038] Typical examples of (meth)acrylate alkyl esters having the above-mentioned biomass-derived alkyl group at the ester terminus include, as described above, esters of biomass-derived alkanol and non-biomass-derived (meth)acrylic acid. The biomass (meth)acrylate alkyl ester is not particularly limited as long as the bio-based carbon content of the acrylic adhesive polymer using the above-mentioned (meth)acrylate ester copolymer as the base polymer and the glass transition temperature (Tg) of the copolymer achieve the desired values. However, from the viewpoint of imparting adhesive strength suitable for dicing tape applications, the biomass (meth)acrylate alkyl ester used as a constituent unit of the (meth)acrylate ester copolymer in the present invention is, for example, a biomass-derived alkyl group having 4 to 12 carbon atoms. ４～１２ Biomass (meth)acrylate alkyl ester (BIO-C) containing an ester of alkanol and non-biomass derived (meth)acrylic acid, i.e., at least one selected from the group "(meth)acrylate alkyl ester having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus". ４～１２ It is preferable to use ).

[0039] Examples of "alkyl (meth)acrylate esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" include n-butyl (meth)acrylate [biomass-derived, 4 carbon atoms], isoamyl (meth)acrylate [biomass-derived, 5 carbon atoms], n-hexyl (meth)acrylate [biomass-derived, 6 carbon atoms], n-heptyl (meth)acrylate [biomass-derived, 7 carbon atoms], 1-methylheptyl (meth)acrylate [biomass-derived, 8 carbon atoms], n-octyl (meth)acrylate [biomass-derived, 8 carbon atoms], lauryl (meth)acrylate [biomass-derived, 12 carbon atoms], etc. These may be used individually or in combination of two or more. Among these, biomass-derived C is preferred in terms of ease of adjusting the Tg of the resulting copolymer and ease of obtaining the materials. ４～１２It is preferable to use an ester of alkanol and acrylic acid derived from non-biomass. Specifically, examples include biomass alkyl acrylates such as n-butyl acrylate [biomass-derived, 4 carbon atoms], isoamyl acrylate [biomass-derived, 5 carbon atoms], n-hexyl acrylate [biomass-derived, 6 carbon atoms], n-heptyl acrylate [biomass-derived, 7 carbon atoms], n-octyl acrylate [biomass-derived, 8 carbon atoms], 1-methylheptyl acrylate [biomass-derived, 8 carbon atoms], and lauryl acrylate [biomass-derived, 12 carbon atoms]. These can be appropriately selected and used alone or in combination of two or more to achieve a good balance between good adhesive properties (for example, a desired Tg of the (meth)acrylic acid ester copolymer as an indicator) and reduced dependence on fossil fuel-based materials (for example, a desired bio-based carbon content of the acrylic adhesive polymer as an indicator).

[0040] From the viewpoint of providing tackiness more suitable for dicing tape applications, among the group of "alkyl (meth)acrylate esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus," it is preferable to use "alkyl (meth)acrylate esters having a biomass-derived alkyl group with 4 to 8 carbon atoms at the ester terminus," and from the viewpoint of balancing with the bio-based carbon content of the acrylic adhesive polymer, it is even more preferable to use "alkyl (meth)acrylate esters having a biomass-derived alkyl group with 6 to 8 carbon atoms at the ester terminus." The above-mentioned "alkyl (meth)acrylate ester having a biomass-derived alkyl group with 4 to 8 carbon atoms at its ester terminus" specifically includes, for example, n-butyl acrylate [biomass-derived with 4 carbon atoms], isoamyl acrylate [biomass-derived with 5 carbon atoms], n-hexyl acrylate [biomass-derived with 6 carbon atoms], n-heptyl acrylate [biomass-derived with 7 carbon atoms], n-octyl acrylate [biomass-derived with 8 carbon atoms], and 1-methylheptyl acrylate [biomass-derived with 8 carbon atoms]. Among these, n-hexyl acrylate, n-heptyl acrylate, n-octyl acrylate, and 1-methylheptyl acrylate, which are alkyl (meth)acrylate esters having a biomass-derived alkyl group with 6 to 8 carbon atoms, are more preferably used. These may be used individually or in combination of two or more.

[0041] As described above, in a preferred embodiment of the present invention, the alkyl (meth)acrylate ester having the biomass-derived alkyl group at the ester terminus may include an alkyl (meth)acrylate ester having a biomass-derived alkyl group with 4 to 12 carbon atoms, preferably 4 to 8 carbon atoms, and more preferably 6 to 8 carbon atoms at the ester terminus.

[0042] The biomass (meth)acrylate alkyl ester used as a constituent unit of the (meth)acrylate copolymer of the present invention is one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the above-mentioned "biomass-derived alkyl groups having 4 to 12 carbon atoms" within a range that does not hinder the effects of the present invention. ４～１２ In addition to the above, other biomass (meth)acrylate alkyl esters with different numbers of carbon atoms in the alkyl group may be included. These other biomass (meth)acrylate alkyl esters are not particularly limited as long as the bio-based carbon content of the acrylic adhesive polymer and the glass transition temperature of the (meth)acrylate copolymer achieve the desired values, but for example, a biomass (meth)acrylate alkyl ester (BIO-C) containing at least one selected from the group "(meth)acrylate alkyl ester having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus" is included. １４～１８ It is preferable to use the above-mentioned "(meth)acrylate alkyl ester having a biomass-derived alkyl group with 14 to 18 carbon atoms at its ester terminus." Specifically, examples of the above-mentioned "biomass-derived alkyl group with 14 to 18 carbon atoms" include 2-butyldecyl (meth)acrylate [biomass-derived with 14 carbon atoms], 2-hexyldecyl (meth)acrylate [biomass-derived with 16 carbon atoms], stearyl (meth)acrylate [biomass-derived with 18 carbon atoms], etc. These may be used individually or in combination of two or more.

[0043] As the above-mentioned alkyl biomass (meth)acrylate, one or more alkyl biomass (meth)acrylates (BIO-C) selected from the above-mentioned "alkyl (meth)acrylates having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus" １４～１８ When using ), one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the aforementioned "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" may be used. ４～１２It is preferably used in combination with ( ). That is, when the number of carbon atoms of the alkyl group at the ester terminal in the (meth)acrylic acid alkyl ester increases, the alkyl group tends to crystallize. Also, depending on the structure, the Tg of the resulting polymer may increase. Then, although the bio-based carbon content of the acrylic adhesive polymer increases, the crystallization of the adhesive layer progresses or the Tg increases, and these phenomena can be factors that reduce the adhesive strength of the adhesive layer to the adherend and the performance stability. Therefore, as the biomass (meth)acrylic acid alkyl ester, one or more biomass (meth)acrylic acid alkyl esters (BIO-C １４～１８ When using ), in order to suppress the influence of the above crystallization and Tg increase, one or more biomass (meth)acrylic acid alkyl esters (BIO-C １４～１８ selected from these groups are not used alone, but one or more biomass (meth)acrylic acid alkyl esters (BIO-C ４～１２ selected from the group of "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminal" are preferably used in combination. By doing so, good adhesive properties (for example, the desired Tg of the (meth)acrylic acid ester copolymer as an index) and a reduced dependence on fossil resource-based materials (for example, the desired bio-based carbon content of the acrylic adhesive polymer as an index) can be achieved in good balance.

[0044] As described above, in one embodiment of the present invention, the (meth)acrylic acid alkyl ester having a biomass-derived alkyl group at the ester terminal may further include a (meth)acrylic acid alkyl ester having a biomass-derived alkyl group with 14 to 18 carbon atoms in addition to the (meth)acrylic acid alkyl ester having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminal.

[0045] A preferred embodiment of the biomass (meth)acrylate alkyl ester used as a constituent unit (copolymer monomer) of the (meth)acrylate ester copolymer in the present invention is: Embodiment (1): One or more biomass (meth)acrylate alkyl esters selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" (BIO-C ４～１２ ), and embodiment (2): one or more biomass (meth)acrylate alkyl esters selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" (BIO-C ４～１２ ) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus". １４～１８ ) combined with two or more alkyl biomass (meth)acrylates (BIO-C ４～１２ +BIO-C １４～１８ ), are some examples.

[0046] The proportion of the (meth)acrylic acid alkyl ester having the biomass-derived alkyl group at the ester terminus in the total copolymer monomer components of the (meth)acrylic acid ester copolymer is not particularly limited, as long as the glass transition temperature (Tg) of the (meth)acrylic acid ester copolymer and the bio-based carbon content of the acrylic adhesive polymer achieve the desired values, that is, as long as the Tg is -18°C or lower and the bio-based carbon content is 50% by mass or more, and can be determined by appropriately selecting and combining the biomass (meth)acrylic acid alkyl ester and other monomers described later.

[0047] As the above biomass (meth)acrylate alkyl ester, one or more biomass (meth)acrylate alkyl esters selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in embodiment (1) above (BIO-C ４～１２In some embodiments, when using the above (meth)acrylic acid ester copolymer, one or more biomass (meth)acrylic acid alkyl esters (BIO-C) selected from the group "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" are used in the entire copolymer monomer component of the above (meth)acrylic acid ester copolymer. ４～１２ The content of ) may be, for example, 65.0% by mass or more, 70.0% by mass or more, or 78.0% by mass or more. In some embodiments, the above "biomass (meth)acrylate alkyl ester (BIO-C)" in the entire copolymer monomer component of the copolymer. ４～１２ The content of ) may be, for example, 93.9% by mass or less, 89.7% by mass or less, or 84.5% by mass or less. In some preferred embodiments, the "biomass (meth)acrylate alkyl ester (BIO-C)" in the entire copolymer monomer component of the copolymer ４～１２ The content of ) may be, for example, in the range of 65.0% by mass or more and 93.9% by mass or less, in the range of 70.0% by mass or more and 89.7% by mass or less, or in the range of 78.0% by mass or more and 84.5% by mass or less. Note that the above-mentioned "biomass (meth)acrylate alkyl ester (BIO-C ４～１２ When using two or more of the above, the total mass of those substances shall be treated as the mass of biomass alkyl (meth)acrylate contained therein, and the same shall apply in the following explanation.

[0048] Furthermore, as the above biomass (meth)acrylate alkyl ester, one or more biomass (meth)acrylate alkyl esters selected from the group of "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in embodiment (2) above (BIO-C ４～１２ ) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus". １４～１８) combined with two or more alkyl biomass (meth)acrylates (BIO-C ４～１２ +BIO-C １４～１８ When using the above (meth)acrylic acid ester copolymer, one or more biomass (meth)acrylic acid alkyl esters (BIO-C) selected from the group "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus" are used in the entire copolymer monomer component of the above (meth)acrylic acid ester copolymer. １４～１８ The content of ) is preferably 30.0% by mass or less, more preferably 25.0% by mass or less, and even more preferably 20.0% by mass or less. The above "Biomass (meth)acrylate alkyl ester (BIO-C １４～１８ If the content of ) exceeds 30.0% by mass, the polymerization reaction during the synthesis of (meth)acrylic acid ester copolymers will not proceed smoothly, making it difficult to obtain high molecular weight polymers. For example, when dicing tape is peeled from the adherend, adhesive residue may easily be generated on the adherend. In addition, the Tg of the resulting copolymer may become too high, potentially reducing the adhesive strength of the adhesive layer. Furthermore, in some embodiments, the content of the above copolymer monomer component exceeds 30.0% by mass of the above "biomass (meth)acrylic acid alkyl ester (BIO-C １４～１８ The content of ) may be, for example, 0.1% by mass or more, 1.0% by mass or more, or 5.0% by mass or more. In some preferred embodiments, the "biomass (meth)acrylate alkyl ester (BIO-C)" in the entire copolymer monomer component of the copolymer １４～１８ The content of ) may be, for example, in the range of 0.1% by mass or more and 30.0% by mass or less, in the range of 1.0% by mass or more and 25.0% by mass or less, or in the range of 5.0% by mass or more and 20.0% by mass or less.

[0049] In this case, the entire copolymer monomer component of the above (meth)acrylic acid ester copolymer contains one or more biomass (meth)acrylic acid alkyl esters selected from the group "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" (BIO-C ４～１２ The content of ) may be, for example, 36.9% by mass or more, 45.5% by mass or more, or 58.0% by mass or more. In addition, the above "biomass (meth)acrylate alkyl ester (BIO-C)" in the entire copolymer monomer component of the above copolymer. ４～１２ The content of ) may be, for example, 93.8% by mass or less, 88.7% by mass or less, or 79.5% by mass or less. In some preferred embodiments, the "biomass (meth)acrylate alkyl ester (BIO-C)" in the entire copolymer monomer component of the copolymer ４～１２ The content of ) may be, for example, in the range of 36.9% by mass or more and 93.8% by mass or less, in the range of 45.5% by mass or more and 88.7% by mass or less, or in the range of 58.0% by mass or more and 79.5% by mass or less.

[0050] Furthermore, the copolymer monomer component of the above copolymer contains one or more biomass (meth)acrylate alkyl esters selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" (BIO-C ４～１２ ) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus" above. １４～１８ ) combined with two or more alkyl biomass (meth)acrylates (BIO-C ４～１２ +BIO-C １４～１８The total content of ) may be, for example, 66.9% by mass or more, 70.5% by mass or more, or 78.0% by mass. Furthermore, the above "biomass (meth)acrylate alkyl ester (BIO-C)" in the entire copolymer monomer component of the above copolymer. ４～１２ +BIO-C １４～１８ The content ratio of the total of the above copolymer monomer components may be, for example, 93.9% by mass or less, 89.7% by mass or less, or 84.5% by mass or less. In some preferred embodiments, the above "biomass (meth)acrylate alkyl ester (BIO-C)" in the whole copolymer monomer component of the above copolymer ４～１２ +BIO-C １４～１８ The content ratio of the total of the above may be, for example, in the range of 66.9% by mass or more and 93.9% by mass or less, in the range of 70.5% by mass or more and 89.7% by mass or less, or in the range of 78.0% by mass or more and 84.5% by mass or less.

[0051] In the technologies disclosed herein, the (meth)acrylic acid ester copolymer, which is the base polymer of the acrylic adhesive polymer of the present invention, is one or more biomass (meth)acrylic acid alkyl esters (BIO-C) selected from the group of "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" as described above, provided that a desired bio-based carbon content is achieved. ４～１２ ) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus". １４～１８ It is not prohibited to replace a portion of the above copolymer with a non-biomass derived alkyl (meth)acrylate [fossil resource derived alkyl (meth)acrylate]. That is, in order to adjust the Tg of the copolymer or to reduce material costs, the above copolymer may contain the above biomass alkyl (meth)acrylate (BIO-C) in its copolymer monomer component. ４～１２ ) and biomass (meth)acrylate alkyl ester (BIO-C １４～１８Other copolymerizable alkyl (meth)acrylate monomers may include non-biomass-derived alkyl (meth)acrylates [alkyl (meth)acrylates derived from fossil resources].

[0052] The above non-biomass-derived alkyl (meth)acrylate [fossil resource-derived alkyl (meth)acrylate] is not particularly limited, but from the viewpoint of the glass transition temperature (Tg) of the copolymer, it is preferable to use an alkyl (meth)acrylate whose Tg when homopolymerized is -40°C or lower. Specifically, examples include n-butyl acrylate, isoamyl acrylate, n-heptyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. Among these, from the viewpoint of low Tg and material cost, it is preferable to use n-butyl acrylate or 2-ethylhexyl acrylate, and more preferably 2-ethylhexyl acrylate. These may be used alone or in combination of two or more.

[0053] When using the above non-biomass derived (meth)acrylate alkyl ester [fossil resource derived (meth)acrylate alkyl ester], the content of the "non-biomass derived (meth)acrylate alkyl ester" in the total copolymer monomer components of the copolymer is preferably kept at, for example, 13.0% by mass or less, and more preferably 10.0% by mass or less, from the viewpoint of appropriately maintaining the high bio-based carbon content of the acrylic adhesive polymer. In some embodiments, the content of the "non-biomass derived (meth)acrylate alkyl ester" in the total copolymer monomer components of the copolymer may be, for example, 0.1% by mass or more, or 3.0% by mass or more. In some preferred embodiments, the content of the "non-biomass derived (meth)acrylate alkyl ester" in the total copolymer monomer components of the copolymer may be, for example, in the range of 0.1% by mass or more and 13.0% by mass or less, or in the range of 3.0% by mass or more and 10.0% by mass or less. In this case, the "biomass (meth)acrylate alkyl ester (BIO-C ４～１２) and "Biomass (meth)acrylate alkyl ester (BIO-C １４～１８ The content ratio of ) can be appropriately adjusted within the range obtained by subtracting the content ratio of the "non-biomass derived (meth)acrylate alkyl ester" from the aforementioned content ratio, so that the glass transition temperature (Tg) of the (meth)acrylate copolymer and the bio-based carbon content of the acrylic adhesive polymer reach the desired values. From the viewpoint of maintaining a high bio-based carbon content of the acrylic adhesive polymer, it is basically preferable not to include the "non-biomass derived (meth)acrylate alkyl ester" as a copolymer monomer component of the copolymer.

[0054] The (meth)acrylic acid ester copolymer, which is the base polymer of the acrylic adhesive polymer of the present invention, contains constituent units derived from monomers having functional groups as constituent units of the copolymer. That is, the copolymer monomer composition of the copolymer contains monomers having functional groups. The functional group referred to here is a thermally reactive functional group that can coexist with an active energy ray reactive carbon-carbon double bond. The monomer having the functional group is copolymerized mainly as a constituent unit that functions as a reaction site for introducing an active energy ray reactive carbon-carbon double bond into the side chain of the copolymer. It also has the function of introducing crosslinking sites for crosslinking and curing by a crosslinking agent, and polar groups to enhance the cohesive force of the adhesive and the adhesiveness to the adherend into the copolymer.

[0055] The monomers having the above-mentioned functional groups are not particularly limited, but examples include hydroxyl group-containing monomers, carboxyl group-containing monomers, acid anhydride group-containing monomers, epoxy group-containing monomers, amino group-containing monomers, amide group-containing monomers, and the like.

[0056] Examples of the above-mentioned hydroxyl group-containing monomers include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

[0057] Examples of the above-mentioned carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, monohydroxyethyl (meth)acrylate phthalate, and the like.

[0058] Examples of monomers containing acid anhydride groups include maleic anhydride and itaconic anhydride.

[0059] Examples of epoxy group (glycidyl group)-containing monomers include epoxy group-containing acrylates such as glycidyl (meth)acrylate, 2-ethyl glycidyl ether (meth)acrylate, and 4-hydroxybutyl acrylate glycidyl ether, as well as allyl glycidyl ether.

[0060] Examples of amino group-containing monomers include aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and (meth)t-butylaminoethyl (meth)acrylate.

[0061] Examples of monomers containing amide groups include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide.

[0062] These monomers having functional groups may be used individually or in combination of two or more.

[0063] Among the monomers having the above-mentioned functional groups, from the viewpoint of control stability when adding or condensing a "compound having a functional group and a carbon-carbon double bond (active energy ray reactive compound)" that can react (e.g., addition reaction, condensation reaction) with the functional group of the (meth)acrylic acid ester copolymer, and from the viewpoint of function as a polar group or crosslinking site, it is preferable to use hydroxyl group-containing monomers or carboxyl group-containing monomers as the monomers having functional groups. Furthermore, considering the Tg of the resulting copolymer, it is even more preferable to mainly use hydroxyl group-containing monomers that have a low Tg when formed into a homopolymer. Specifically, as hydroxyl group-containing monomers, for example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, etc. are preferred, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are more preferred. Also, as carboxyl group-containing monomers, for example, acrylic acid or methacrylic acid are preferred, and from the viewpoint of appropriately maintaining the high bio-based carbon content of the acrylic adhesive polymer, it is even more preferable to use biomass-derived methacrylic acid.

[0064] The proportion of the above-mentioned "monomer having a functional group" in the total copolymer monomer components of the above copolymer is not particularly limited, but should be appropriately determined depending on the form of the biomass (meth)acrylate alkyl ester used, from the viewpoint of setting the active energy ray-reactive carbon-carbon double bond concentration of the acrylic adhesive polymer within an appropriate range and appropriately maintaining the high bio-based carbon content of the acrylic adhesive polymer. For example, as the above-mentioned biomass (meth)acrylate alkyl ester, one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group of "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in the above-mentioned form (1) may be used. ４～１２When using the above copolymer, the content of the above "monomer having a functional group" in the total copolymer monomer components of the above copolymer is preferably in the range of 6.1% by mass or more and 35.0% by mass or less. More preferably, it is in the range of 10.3% by mass or more and 30.0% by mass or less, and even more preferably, in the range of 15.5% by mass or more and 22.0% by mass or less.

[0065] Furthermore, as the above biomass (meth)acrylate alkyl ester, one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group of "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in the above embodiment (2) ４～１２ ) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus". １４～１８ ) combined with two or more alkyl biomass (meth)acrylates (BIO-C ４～１２ +BIO-C １４～１８ When using the above copolymer, the content of the above "monomer having a functional group" in the total copolymer monomer components of the above copolymer is preferably in the range of 6.1% by mass or more and 33.1% by mass or less. More preferably, it is in the range of 10.3% by mass or more and 29.5% by mass or less, and even more preferably, in the range of 15.5% by mass or more and 22.0% by mass or less.

[0066] In some preferred embodiments, monomers combining a "hydroxyl group-containing monomer" and a "carboxyl group-containing monomer" may be used as the monomer having the above functional group. For example, as the above biomass (meth)acrylate alkyl ester, one or more biomass (meth)acrylate alkyl esters selected from the group of "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in embodiment (1) described above (BIO-C ４～１２When using the above copolymer, it is preferable to use them in combination with the content of the "hydroxyl group-containing monomer" in the entire copolymer monomer component being in the range of 6.0% by mass or more and 30.0% by mass or less, and the content of the "carboxyl group-containing monomer" being in the range of 0.1% by mass or more and 5.0% by mass or less. Regarding the content of the "hydroxyl group-containing monomer" and the "carboxyl group-containing monomer" in the entire copolymer monomer component of the above copolymer, it is more preferable to use them in combination with the content of the "hydroxyl group-containing monomer" in the range of 10.0% by mass or more and 27.0% by mass or less, and the content of the "carboxyl group-containing monomer" being in the range of 0.3% by mass or more and 3.0% by mass or less, and it is even more preferable to use them in combination with the content of the "hydroxyl group-containing monomer" in the range of 15.0% by mass or more and 20.0% by mass or less, and the content of the "carboxyl group-containing monomer" being in the range of 0.5% by mass or more and 2.0% by mass or less. By using a combination of "hydroxyl group-containing monomers" and "carboxyl group-containing monomers" in this way, the Tg of the resulting (meth)acrylic acid ester copolymer can be maintained within a desired range, and the addition reaction of "functional groups (e.g., isocyanate groups) and compounds having carbon-carbon double bonds (active energy ray reactive compounds)" described later can be appropriately carried out on the copolymer, and polar groups can also be appropriately introduced.

[0067] Furthermore, as the above biomass (meth)acrylate alkyl ester, one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group of "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in the above embodiment (2) ４～１２ ) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus". １４～１８ ) combined with two or more alkyl biomass (meth)acrylates (BIO-C ４～１２ +BIO-C １４～１８When using the above copolymer, it is preferable to use them in combination with the content of the "hydroxyl group-containing monomer" in the entire copolymer monomer component being in the range of 6.0% by mass or more and 30.0% by mass or less, and the content of the "carboxyl group-containing monomer" being in the range of 0.1% by mass or more and 3.1% by mass or less. Regarding the content of the "hydroxyl group-containing monomer" and the "carboxyl group-containing monomer" in the entire copolymer monomer component of the above copolymer, it is more preferable to use them in combination with the content of the "hydroxyl group-containing monomer" in the range of 10.0% by mass or more and 27.0% by mass or less, and the content of the "carboxyl group-containing monomer" being in the range of 0.3% by mass or more and 2.5% by mass or less, and it is even more preferable to use them in combination with the content of the "hydroxyl group-containing monomer" in the range of 15.0% by mass or more and 20.0% by mass or less, and the content of the "carboxyl group-containing monomer" being in the range of 0.5% by mass or more and 2.0% by mass or less.

[0068] Furthermore, the (meth)acrylic acid ester copolymer may optionally contain other monomer components as copolymer monomer components, to the extent that they do not interfere with the effects of the present invention, for the purpose of imparting cohesive force, heat resistance, and other properties. Examples of other monomer components include, specifically, cyano group-containing monomers such as (meth)acrylonitrile, olefin monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene, styrene monomers such as styrene, α-methylstyrene, and vinyltoluene, vinyl ester monomers such as vinyl acetate and vinyl propionate, vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether, halogen atom-containing monomers such as vinyl chloride and vinylidene chloride, alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and monomers having nitrogen atom-containing rings such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine. These other monomer components may be used individually or in combination of two or more. From the viewpoint of increasing the bio-based carbon content of the acrylic adhesive polymer, it is preferable not to include these other monomers as copolymer monomer components of the copolymer, unless they are biomass materials.

[0069] The preferred (meth)acrylic acid ester copolymers obtained by copolymerizing the above-mentioned monomers are not particularly limited, but typical examples include ternary copolymers containing at least a biomass-derived alkyl (meth)acrylic acid ester, a hydroxyl group-containing monomer, and a carboxyl group-containing monomer. Specifically, for example, a terpolymer of "biomass-derived n-octyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a terpolymer of "biomass-derived n-heptyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a terpolymer of "biomass-derived 1-methylheptyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a terpolymer of "biomass-derived lauryl (meth)acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a terpolymer of "biomass-derived n-octyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a quaternary copolymer of "biomass-derived n-butyl acrylate / biomass-derived n-octyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", and "biomass-derived n-butyl acrylate / biomass-derived n-heptyl acrylate / 2-hydroxyethyl acrylate A quaternary copolymer of "roxyethyl acrylate / methacrylic acid", a quaternary copolymer of "biomass-derived n-butyl acrylate / biomass-derived 1-methylheptyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a quaternary copolymer of "biomass-derived n-butyl acrylate / biomass-derived lauryl (meth) acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a quaternary copolymer of "biomass-derived n-butyl acrylate / biomass-derived stearyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a quaternary copolymer of "biomass-derived n-octyl acrylate / biomass-derived stearyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid", a quaternary copolymer of "biomass-derived 1-methylheptyl acrylate / biomass-derived stearyl acrylate / 4-hydroxybutyl acrylate / methacrylic acid",Examples include, but are not limited to, pentomer copolymers of "biomass-derived n-octyl acrylate / biomass-derived stearyl acrylate / 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid" and pentomer copolymers of "biomass-derived n-butyl acrylate / biomass-derived n-octyl acrylate / biomass-derived stearyl acrylate / 2-ethylhexyl acrylate / 2-hydroxyethyl acrylate / methacrylic acid". Here, monomers not explicitly labeled "biomass-derived" refer to monomers derived from fossil resources.

[0070] The (meth)acrylic acid ester copolymer, which includes constituent units derived from an alkyl (meth)acrylate ester (biomass (meth)acrylic acid ester) having a biomass-derived alkyl group at its ester terminus and constituent units derived from a monomer having a functional group, has a glass transition temperature (Tg) of -18°C or lower, and in some embodiments, it may be, for example, -25°C or lower, or -30°C or lower. Also, in some embodiments, it may be, for example, -50°C or higher, -45°C or higher, or -40°C or higher. Furthermore, in some preferred embodiments, the glass transition temperature (Tg) may be in the range of -50°C or higher and -18°C or lower, in the range of -45°C or higher and -25°C or lower, or in the range of -40°C or higher and -30°C or lower. Also, in another embodiment, it may be in the range of -40°C or higher and -18°C or lower.

[0071] The acrylic adhesive polymer of the present invention can be obtained by using the above-mentioned "(meth)acrylic acid ester copolymer containing constituent units derived from monomers having functional groups as constituent units of the copolymer" as a base polymer, and reacting it with a "compound having functional groups and carbon-carbon double bonds (active energy ray reactive compound)" that can react with the functional groups of the copolymer (e.g., addition reaction, condensation reaction).

[0072] As such "compounds having a functional group and a carbon-carbon double bond," for example, when performing an addition reaction to a hydroxyl group in the side chain of the copolymer, isocyanate compounds having a (meth)acryloyloxy group, such as 2-methacryloyloxyethyl isocyanate, 4-methacryloyloxy-n-butyl isocyanate, 2-acryloyloxyethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate, can be used as "compounds having a functional group and a carbon-carbon double bond." Furthermore, when performing an addition reaction to a carboxyl group in the side chain of the copolymer, glycidyl (meth)acrylate and 2-(1-aziridinyl)ethyl (meth)acrylate can be used as "compounds having a functional group and a carbon-carbon double bond." In addition, when performing an addition reaction to a glycidyl group in the side chain of the copolymer, (meth)acrylic acid can be used as "compounds having a functional group and a carbon-carbon double bond." In other words, examples of combinations between the functional groups of the above-mentioned "(meth)acrylic acid ester copolymer" and the functional groups of the above-mentioned "compound having a functional group and a carbon-carbon double bond" include combinations of a hydroxyl group and an isocyanate group, a carboxyl group and a glycidyl group, a carboxyl group and an aziridine group, and a glycidyl group and a carboxyl group.

[0073] The above reaction is not particularly limited, but from the viewpoint of ease of reaction tracking (stability of control) and technical difficulty, the most preferred method is to add a compound having an isocyanate group and a carbon-carbon double bond (an isocyanate compound having a (meth)acryloyloxy group) that can react with the hydroxyl group in the side chain of the (meth)acrylic acid ester copolymer. In this case, for example, as described above, it is preferable to keep the content of the "hydroxyl group-containing monomer" in the total copolymer monomer components of the copolymer in the range of 6.0% by mass or more and 30.0% by mass or less.

[0074] For example, when performing the above addition reaction, the amount of "compound having a functional group and a carbon-carbon double bond (active energy ray reactive compound)" used is preferably in the range of 5.0 parts by mass to 25.0 parts by mass, more preferably in the range of 7.0 parts by mass to 20.0 parts by mass, and even more preferably in the range of 10.0 parts by mass to 17.0 parts by mass, per 100 parts by mass of the base polymer, the (meth)acrylic acid ester copolymer. If the amount of "compound having a functional group and a carbon-carbon double bond" used is less than 5.0 parts by mass, the amount of active energy ray reactive carbon-carbon double bond introduced is too small, which may result in insufficient curing and shrinkage of the adhesive layer after irradiation with active energy rays, and the adhesive strength may not decrease sufficiently. On the other hand, if the amount of "compound having a functional group and a carbon-carbon double bond" used exceeds 25.0 parts by mass, the effect of curing and shrinking of the adhesive layer by irradiation with active energy rays will saturate, and the stability of the (meth)acrylic acid ester copolymer will decrease, which may make it difficult to manufacture the acrylic adhesive polymer. Furthermore, "compounds having functional groups and carbon-carbon double bonds (active energy ray reactive compounds)" are typically derived from fossil resources, which makes it impossible to satisfy the desired value for the bio-based carbon content of acrylic adhesive polymers.

[0075] Furthermore, when carrying out the above addition reaction, it is preferable to adjust the amount of the "compound having functional groups and carbon-carbon double bonds" used so that functional groups such as hydroxyl groups, carboxyl groups, and glycidyl groups remain, in order to crosslink the above-mentioned active energy ray-curable acrylic adhesive polymer with a crosslinking agent and further increase its molecular weight.

[0076] In the above addition reaction, it is preferable to use a polymerization inhibitor so as to maintain the ray reactivity of the carbon-carbon double bond. As such a polymerization inhibitor, quinone-based polymerization inhibitors such as hydroquinone monomethyl ether are preferred. The amount of polymerization inhibitor is not particularly limited, but it is usually in the range of 0.01 parts by mass or more and 0.1 parts by mass or less, relative to the total amount of the "base polymer (meth)acrylic acid ester copolymer" and the "compound having a functional group and a carbon-carbon double bond".

[0077] In the (meth)acrylic acid ester copolymer, which is the base polymer of the acrylic adhesive polymer of the present invention, the content of constituent units derived from the (meth)acrylic acid alkyl ester having the biomass-derived alkyl group at the ester terminus is not particularly limited as long as the glass transition temperature (Tg) of the (meth)acrylic acid ester copolymer and the bio-based carbon content of the acrylic adhesive polymer using the copolymer as the base polymer achieve the desired values. For example, as the (meth)acrylic acid alkyl ester having the biomass-derived alkyl group at the ester terminus, one or more biomass (meth)acrylic acid alkyl esters (BIO-C) selected from the group of "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in the above-described embodiment (1) may be used. ４～１２ When using the above-mentioned "alkyl (meth)acrylate ester having a biomass-derived alkyl group with 4 to 12 carbon atoms at its ester terminus," the content of constituent units derived from the above-mentioned "alkyl (meth)acrylate ester having an alkyl group derived from biomass with 4 to 12 carbon atoms at its ester terminus" may be in the range of, for example, 65.0% to 93.9% by mass, preferably 70.0% to 89.7% by mass, and more preferably 78.0% to 84.5% by mass, relative to the total constituent units contained in the above-mentioned (meth)acrylate ester copolymer. In this case, the content of constituent units derived from monomers having the above-mentioned functional group may be in the range of, for example, 6.1% to 35.0% by mass, preferably 10.3% to 30.0% by mass, and more preferably 15.5% to 22.0% by mass, relative to the total constituent units contained in the above-mentioned (meth)acrylate ester copolymer.

[0078] Furthermore, as the (meth)acrylate alkyl ester having the above biomass-derived alkyl group at the ester terminus, one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group of "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in the above embodiment (2) ４～１２) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus". １４～１８ ) combined with two or more alkyl biomass (meth)acrylates (BIO-C ４～１２ +BIO-C １４～１８ When using the above-mentioned "alkyl (meth)acrylate ester having a biomass-derived alkyl group with 4 to 12 carbon atoms at its ester terminus" and "alkyl (meth)acrylate ester having a biomass-derived alkyl group with 14 to 18 carbon atoms at its ester terminus", the total content ratio of constituent units derived from these two groups may be, for example, 66.9% by mass or more and 93.9% by mass or less, preferably 70.5% by mass or more and 89.7% by mass or less, and more preferably 78.0% by mass or more and 84.5% by mass or less, relative to the total constituent units contained in the above-mentioned (meth)acrylate ester copolymer. In this case, the content ratio of constituent units derived from monomers having the above-mentioned functional group may be, for example, 6.1% by mass or more and 33.1% by mass or less, preferably 10.3% by mass or more and 29.5% by mass or less, and more preferably 15.5% by mass or more and 22.0% by mass or less, relative to the total constituent units contained in the above-mentioned (meth)acrylate ester copolymer.

[0079] Furthermore, in the (meth)acrylic acid ester copolymer, which is the base polymer of the acrylic adhesive polymer, one or more biomass (meth)acrylic acid alkyl esters selected from the group of "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in the above-described embodiment (1) (BIO-C) are used as the (meth)acrylic acid alkyl esters having the biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus. ４～１２When using ) and using hydroxyl group-containing monomers and carboxyl group-containing monomers as monomers having the above-mentioned functional groups, the content of constituent units derived from the hydroxyl group-containing monomer may be in the range of, for example, 6.0% by mass or more and 30.0% by mass or less, preferably 10.0% by mass or more and 27.0% by mass or less, and more preferably 15.0% by mass or more and 20.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer. The content of constituent units derived from the carboxyl group-containing monomer may be in the range of, for example, 0.1% by mass or more and 5.0% by mass or less, preferably 0.3% by mass or more and 3.0% by mass or less, and even more preferably 0.5% by mass or more and 2.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer.

[0080] Furthermore, in a (meth)acrylic acid ester copolymer which is the base polymer of an acrylic adhesive polymer, one or more biomass (meth)acrylic acid alkyl esters selected from the group of "(meth)acrylic acid alkyl esters having a biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus" in the above-described embodiment (2) (BIO-C) are used as the (meth)acrylic acid alkyl esters having the biomass-derived alkyl group with 4 to 12 carbon atoms at the ester terminus. ４～１２ ) and one or more biomass (meth)acrylate alkyl esters (BIO-C) selected from the group "(meth)acrylate alkyl esters having a biomass-derived alkyl group with 14 to 18 carbon atoms at the ester terminus". １４～１８ ) combined with two or more alkyl biomass (meth)acrylates (BIO-C ４～１２ +BIO-C １４～１８When using ) and using hydroxyl group-containing monomers and carboxyl group-containing monomers as monomers having the above functional groups, the content of constituent units derived from the hydroxyl group-containing monomer may be in the range of, for example, 6.0% by mass or more and 30.0% by mass or less, preferably 10.0% by mass or more and 27.0% by mass or less, and more preferably 15.0% by mass or more and 20.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer. The content of constituent units derived from the carboxyl group-containing monomer may be in the range of, for example, 0.1% by mass or more and 3.1% by mass or less, preferably 0.3% by mass or more and 2.5% by mass or less, and even more preferably 0.5% by mass or more and 2.0% by mass or less, relative to the total constituent units contained in the (meth)acrylic acid ester copolymer.

[0081] The above-mentioned acrylic adhesive polymer preferably has a hydroxyl value in the range of, for example, 3.0 mg KOH / g to 95.0 mg KOH / g, more preferably in the range of 19.0 mg KOH / g to 65.0 mg KOH / g, and even more preferably in the range of 20.0 mg KOH / g to 55.0 mg KOH / g.

[0082] The above-mentioned acrylic adhesive polymer preferably has an acid value in the range of, for example, 0.5 mg KOH / g to 30.0 mg KOH / g, more preferably in the range of 1.5 mg KOH / g to 20.0 mg KOH / g, and even more preferably in the range of 2.0 mg KOH / g to 12.0 mg KOH / g.

[0083] The carbon-carbon double bond concentration of the above-mentioned acrylic adhesive polymer (molar concentration per gram of acrylic adhesive polymer) should be an amount that provides a sufficient reduction in adhesive strength in the adhesive layer containing the adhesive composition after irradiation with active energy rays such as ultraviolet (UV) rays. This concentration varies depending on the usage conditions, such as the amount of active energy ray irradiation, and is not unique. However, it is preferably in the range of 0.30 mmol / g to 1.30 mmol / g, more preferably in the range of 0.40 mmol / g to 1.10 mmol / g, and even more preferably in the range of 0.55 mmol / g to 0.95 mmol / g.

[0084] The bio-based carbon content of the above-mentioned acrylic adhesive polymer is 50% by mass or more. A high bio-based carbon content in the acrylic adhesive polymer means that the amount of fossil resource-based materials, such as petroleum, used is small, and from this viewpoint, a higher bio-based carbon content in the acrylic adhesive polymer is preferable. The bio-based carbon content of the acrylic adhesive polymer may be, for example, 51% by mass or more, or 52% by mass or more. Although the upper limit of the bio-based carbon content is 100% by definition, the acrylic adhesive polymer disclosed herein may contain fossil resource-derived materials as constituent units of the (meth)acrylic acid ester copolymer, which is its base polymer, or as compounds introduced into its side chains. Therefore, the bio-based carbon content of the acrylic adhesive polymer is typically less than 100%. From the viewpoint of making it easier to ensure adhesive performance suitable for dicing tape applications and from the viewpoint of ease of obtaining materials, in some embodiments, the bio-based carbon content of the acrylic adhesive polymer may be, for example, 72% by mass or less, 70% by mass or less, and 65% by mass or less when adhesive properties are more important. In some preferred embodiments, the bio-based carbon content of the acrylic adhesive polymer may be in the range of 50% by mass or more and 72% by mass or less, in the range of 51% by mass or more and 70% by mass or less, in the range of 52% by mass or more and 65% by mass or less, and in the range of 52% by mass or more and 60% by mass or less.

[0085] In some embodiments of the present invention, the non-volatile component (adhesive layer) of the active energy ray-curable peelable adhesive composition is prepared by mainly comprising an acrylic adhesive polymer having a bio-based carbon content of 50% by mass or more. In such embodiments, the non-volatile component (adhesive layer) of the adhesive composition has a bio-based carbon content of a predetermined value or higher. The bio-based carbon content of the non-volatile component (adhesive layer) of the above adhesive composition is not particularly limited, but may be, for example, 43% by mass or more, 45% by mass or more, 49% by mass or more, or 51% by mass or more. From the viewpoint of making it easier to ensure adhesive performance suitable for dicing tape applications and from the viewpoint of ease of obtaining materials, in some embodiments, the bio-based carbon content of the non-volatile component (adhesive layer) of the above adhesive composition may be, for example, 72% by mass or less, 70% by mass or less, or 65% by mass or less when adhesive properties are more important. In some preferred embodiments, the bio-based carbon content of the non-volatile components (adhesive layer) of the adhesive composition may be in the range of 43% by mass or more and 72% by mass or less, in the range of 45% by mass or more and 70% by mass or less, in the range of 49% by mass or more and 65% by mass or less, or in the range of 49% by mass or more and 60% by mass or less.

[0086] Furthermore, the bio-based content of the non-volatile components (adhesive layer) of the acrylic adhesive polymer and adhesive composition, that is, the proportion of biomass-derived carbon in the total carbon contained in the non-volatile components (adhesive layer) of the acrylic adhesive polymer and adhesive composition, can be calculated from the carbon isotope content with mass number 14, measured in accordance with ASTM D6866.

[0087] The (meth)acrylic acid ester copolymer, which serves as the base polymer for the acrylic adhesive polymer in the present invention, contains constituent units derived from biomass (meth)acrylic acid acrylic ester and constituent units derived from monomers having functional groups. This copolymer is obtained by polymerizing a mixture of the above-mentioned monomers, and this polymerization can be carried out by any method such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization. Preferred reaction modes for this polymerization include free radical polymerization and living radical polymerization.

[0088] The active energy ray-curable release adhesive composition of the present invention contains the above-mentioned acrylic adhesive polymer as a main component, and also contains a photopolymerization initiator and a crosslinking agent, which will be described later. The content of the acrylic adhesive polymer included as a main component may be in the range of, for example, 85.00% by mass or more and less than 100.00% by mass, preferably 94.00% by mass or more and 99.50% by mass or less, more preferably 97.50% by mass or more and 99.00% by mass or less, and particularly preferably 98.00% by mass or more and 98.50% by mass or less, based on solid content.

[0089] <Photopolymerization Initiator> The active energy ray curable release adhesive composition of the present invention contains a photopolymerization initiator that generates radicals upon irradiation with active energy rays. The photopolymerization initiator senses irradiation of the adhesive layer with active energy rays during adhesion and release, generates radicals, and initiates the crosslinking reaction of carbon-carbon double bonds in the acrylic adhesive polymer in the adhesive layer. As a result, the adhesive layer further hardens and shrinks under irradiation with active energy rays, reducing the adhesive strength to the adherend. Preferred photopolymerization initiators are compounds that generate radical active species upon irradiation with ultraviolet light (UV) or the like. Examples include alkylphenone-based radical polymerization initiators, acylphosphine oxide-based radical polymerization initiators, and oxime ester-based radical polymerization initiators. These photopolymerization initiators may be used alone or in combination of two or more.

[0090] Examples of the alkylphenone-based radical polymerization initiators mentioned above include benzylmethyl ketal-based radical polymerization initiators, α-hydroxyalkylphenone-based radical polymerization initiators, and α-aminoalkylphenone-based radical polymerization initiators.

[0091] Examples of the above-mentioned benzylmethyl ketal-based radical polymerization initiators include, for example, 2,2'-dimethoxy-1,2-diphenylethane-1-one (e.g., trade name: Omnirad 651, manufactured by IGM Resins B.V.). Examples of the above-mentioned α-hydroxyalkylphenone-based radical polymerization initiators include, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one (trade name: Omnirad 1173, manufactured by IGM Resins B.V.), 1-hydroxycyclohexylphenyl ketone (trade name: Omnirad 184, manufactured by IGM Resins B.V.), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one (trade name: Omnirad 2959, manufactured by IGM Resins B.V.), and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one (trade name: Omnirad 127, manufactured by IGM Resins B.V.). Examples of the above-mentioned α-aminoalkylphenone-based radical polymerization initiators include, for example, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: Omnirad 907, manufactured by IGM Resins B.V.), 2-benzyl-2-(dimethylamino)-4'-morpholinobylophenone (trade name: Omnirad 369, manufactured by IGM Resins B.V.), and 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one (trade name: Omnirad 379EG, manufactured by IGM Resins B.V.).

[0092] Examples of the above-mentioned acylphosphine oxide-based radical polymerization initiators include, for example, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Omnirad TPO, manufactured by IGM Resins B.V.) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name: Omnirad 819, manufactured by IGM Resins B.V.).

[0093] Examples of the above-mentioned oxime ester-based radical polymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl]-,2-(O-benzoyl oxime) (trade name: OmniradOXE-01, manufactured by IGM Resins B.V.).

[0094] The content of the above-mentioned photopolymerization initiator may be in the range of, for example, 0.10 parts by mass or more and 10.00 parts by mass or less, preferably 0.50 parts by mass or more and 5.00 parts by mass or less, and more preferably 1.00 parts by mass or more and 2.00 parts by mass or less, per 100.00 parts by mass of the solid content of the acrylic adhesive polymer. If the content of the photopolymerization initiator is less than 0.10 parts by mass, the photoreactivity to active energy rays is insufficient, and even if the acrylic adhesive polymer is irradiated with active energy rays, the photoradical crosslinking reaction of the acrylic adhesive polymer does not occur sufficiently, resulting in insufficient curing and shrinkage of the adhesive. As a result, for example, when the adhesive composition of the present invention is used in the adhesive layer of semiconductor processing adhesive tapes such as dicing tapes, the effect of reducing the adhesive strength in the adhesive layer after irradiation with active energy rays becomes small, and there is a risk that semiconductor chip pickup failures will increase. On the other hand, if the content of the photopolymerization initiator exceeds 10.0 parts by mass, its effect saturates, which is undesirable from an economic standpoint. In addition, depending on the type of photopolymerization initiator, the adhesive layer may yellow and have an undesirable appearance. Furthermore, since the above-mentioned photopolymerization initiators are typically materials derived from fossil resources, the bio-based carbon content of the non-volatile components (adhesive layer) of the adhesive composition decreases, which is undesirable from the viewpoint of reducing dependence on fossil resource-based materials.

[0095] Furthermore, compounds such as dimethylaminoethyl methacrylate and isoamyl 4-dimethylaminobenzoate may be included in the adhesive composition as sensitizers for such photopolymerization initiators.

[0096] <Crosslinking Agent> The active energy ray curable release adhesive composition of the present invention further contains a crosslinking agent for increasing the molecular weight of the acrylic adhesive polymer. The crosslinking agent is not particularly limited, and known crosslinking agents having functional groups that can react with functional groups such as hydroxyl groups, carboxyl groups, and glycidyl groups, which are functional groups of the acrylic adhesive polymer, can be used. Specifically, examples include polyisocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, melamine resin crosslinking agents, urea resin crosslinking agents, acid anhydride compound crosslinking agents, polyamine crosslinking agents, and carboxyl group-containing polymer crosslinking agents. Among these, polyisocyanate crosslinking agents or epoxy crosslinking agents are preferred from the viewpoint of reactivity and versatility. These crosslinking agents may be used alone or in combination of two or more.

[0097] Examples of the polyisocyanate crosslinking agents mentioned above include polyisocyanate compounds having an isocyanurate ring, adductopolyisocyanate compounds obtained by reacting trimethylolpropane with hexamethylene diisocyanate, adductopolyisocyanate compounds obtained by reacting trimethylolpropane with tolylene diisocyanate, adductopolyisocyanate compounds obtained by reacting trimethylolpropane with xylylene diisocyanate, and adductopolyisocyanate compounds obtained by reacting trimethylolpropane with isophorone diisocyanate. These can be used individually or in combination of two or more.

[0098] Examples of the epoxy crosslinking agents mentioned above include bisphenol A / epichlorohydrin type epoxy resins, 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 erythritol, diglycerol polyglycidyl ether, 1,3'-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-m-xylenediamine. These can be used individually or in combination of two or more.

[0099] The crosslinking agent content may be, for example, in the range of 0.01 parts by mass to 5.00 parts by mass per 100.00 parts by mass of the solids content of the acrylic adhesive polymer, preferably in the range of 0.05 parts by mass to 1.00 parts by mass, and more preferably in the range of 0.10 parts by mass to 0.50 parts by mass. If the crosslinking agent content is less than 0.01 parts by mass, the crosslinking and curing of the adhesive layer may be insufficient, and the cohesive force of the adhesive layer may decrease. On the other hand, if the crosslinking agent content exceeds 5.00 parts by mass, the adhesive layer may become too hard, and the adhesive strength of the adhesive layer may decrease. Furthermore, since the above crosslinking agent is typically a material derived from fossil resources, the bio-based carbon content of the non-volatile components (adhesive layer) of the adhesive composition decreases, which is undesirable from the viewpoint of reducing dependence on fossil resource-based materials.

[0100] The conditions for aging to react the crosslinking agent with the functional groups of the acrylic adhesive polymer after forming an adhesive layer with the active energy ray curable peelable adhesive composition of the present invention are not particularly limited, but for example, the temperature can be set appropriately within the range of 23°C to 80°C, and the time within the range of 24 hours to 168 hours.

[0101] <Other> The active energy ray-curable peelable adhesive composition of the present invention may optionally contain other additives such as polyfunctional acrylic monomers, polyfunctional acrylic oligomers, tackifiers, fillers, antioxidants, colorants, flame retardants, antistatic agents, surfactants, silane coupling agents, and leveling agents, as long as they do not impair the effects of the present invention. However, from the viewpoint of increasing the bio-based carbon content of the adhesive composition and reducing the dependence on fossil fuel-based materials, it is preferable not to include these additives in the adhesive composition unless they are biomass materials.

[0102] The adhesive composition of the present invention has a high biomass-derived carbon content and reduces reliance on fossil fuel-based materials, yet exhibits physical properties equivalent to conventional adhesive compositions with a low biomass-derived carbon content or no biomass-derived carbon at all. Therefore, the adhesive composition of the present invention can be used in various applications where conventional adhesive compositions are used. The adhesive composition of the present invention is an active energy ray-curable release-type adhesive composition that has sufficient adhesive strength before irradiation with active energy rays such as ultraviolet rays, and its adhesive strength decreases after irradiation with active energy rays such as ultraviolet rays. For example, it can be used as the adhesive layer of a release-type adhesive sheet for temporary protection when processing workpieces such as semiconductor devices, printed circuit boards, LED substrates, glass substrates, glass processed products, metal plates, and plastic plates.

[0103] [Adhesive Tape for Semiconductor Processing] In one embodiment, the present invention includes an adhesive tape for semiconductor processing comprising an adhesive layer containing an active energy ray curable adhesive composition. The adhesive layer containing the active energy ray curable adhesive composition has the property of hardening and shrinking when irradiated with active energy rays such as ultraviolet rays (UV), thereby reducing its adhesive strength to the adherend.

[0104] The above adhesive layer can be produced by, for example, applying and drying the above active energy ray-curable adhesive composition to form a film.

[0105] The thickness of the adhesive layer may be, for example, in the range of 1 μm to 30 μm, preferably 3 μm to 25 μm, and more preferably 5 μm to 20 μm.

[0106] The adhesive tape for semiconductor processing may comprise a base film and an adhesive layer on the base film containing an active energy ray-curable adhesive composition.

[0107] The base film is not particularly limited in material or form, and may be, for example, a resin film. The resin film may be a film comprising, for example, a resin composition containing polyethylene terephthalate (PET), linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE) ethylene-α-olefin copolymer, polypropylene (PP), ionomer resin (e.g., ethylene-unsaturated carboxylic acid copolymer, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid alkyl ester terpolymer, ethylene-unsaturated carboxylic acid alkyl ester copolymer, ethylene-vinyl ester copolymer, ethylene-unsaturated carboxylic acid alkyl ester-carbon monoxide copolymer, or unsaturated carboxylic acid grafts thereof), polyamide resin (PA), or mixtures thereof, or composed of such resin compositions.

[0108] The base film disclosed herein may contain biomass materials in the resin composition from the viewpoint of reducing the amount of fossil resource-based materials used. The biomass materials that can constitute the base film are not particularly limited, but examples include: biomass polyesters such as biomass polyethylene terephthalate (biomass PET) and biomass polytrimethylene terephthalate (biomass PTT); polylactic acid; biomass polyethylene such as biomass high-density polyethylene (biomass HDPE), biomass low-density polyethylene (biomass LDPE), and biomass linear low-density polyethylene (biomass LLDPE), and biomass polyolefins such as biomass polypropylene (biomass PP); biomass poly(3-hydroxybutyrate-co-3-hydroxyhexanoate); biomass polyamides such as polyhexamethylene sebakamid and poly(xylylene sebakamid); biomass polyurethanes such as biomass polyester ether urethane and biomass polyether urethane; cellulose resins; and the like. These can be used individually or in combination of two or more. In particular, biomass polyolefins such as biomass HDPE, biomass LDPE, biomass LLDPE, and biomass PP, and biomass polyesters such as biomass PET and biomass PTT are preferred, with biomass polyolefins being more preferred. In adhesive tapes and adhesive sheets that use a film made from a resin composition containing the above biomass materials as a base material, the amount of fossil resource-based materials used can be reduced.

[0109] The composition of the base film is not particularly limited and may be a single layer of a single resin composition, a laminate consisting of multiple layers of the same resin composition, or a laminate consisting of multiple layers of different resin compositions. In the case of a laminate consisting of multiple layers, the number of layers is not particularly limited, but is preferably in the range of two to five layers, and more preferably two or three layers.

[0110] The thickness of the base film may be, for example, in the range of 60 μm to 150 μm, preferably 70 μm to 120 μm.

[0111] Depending on the manufacturing conditions and usage conditions of the semiconductor processing adhesive tape, an anchor coat layer may be provided between the base film and the adhesive layer, with the composition of the base film matching the base film. Providing an anchor coat layer improves the adhesion between the base film and the adhesive layer.

[0112] Adhesive tapes for semiconductor processing may have a release liner on the side opposite to the substrate film of the adhesive layer (one side of the surface) as needed. The release liner can be used in any way, but examples include resin films made from synthetic resins such as polyethylene, polypropylene, and polyethylene terephthalate. Furthermore, the surface of these release liners may be treated with a release agent such as a silicone-based release agent, a long-chain alkyl-based release agent, or a fluorine-based release agent to improve their release properties from the adhesive layer. The thickness of the release liner is not particularly limited, but a thickness in the range of 10 μm to 200 μm is preferably used.

[0113] The adhesive tape for semiconductor processing may preferably be a dicing tape that can be used in the manufacturing process of semiconductor devices.

[0114] In some embodiments, the adhesive layer of the adhesive tape for semiconductor processing may have an adhesive strength of, for example, 0.55 N / 10 mm to 5.60 N / 10 mm, preferably 0.70 N / 10 mm to 4.20 N / 10 mm, and more preferably 1.00 N / 10 mm to 2.80 N / 10 mm before UV irradiation at 23°C.

[0115] In some embodiments, the adhesive layer of the adhesive tape for semiconductor processing has an adhesive strength (integrated UV light intensity: 300 mJ / cm²) after UV irradiation to a SUS304BA plate at 23°C. ２The peeling angle (90 degrees, peeling speed (5 mm / sec)) may be, for example, 0.45 N / 10 mm or less, 0.35 N / 10 mm or less, 0.25 N / 10 mm or less, or 0.10 N / 10 mm or less. Furthermore, the adhesive strength to the SUS304BA plate after UV irradiation at 23°C may be, for example, 0.01 N / 10 mm or more, 0.02 N / 10 mm or more, 0.03 N / 10 mm or more, or 0.04 N / 10 mm or more. In some preferred embodiments, the adhesive strength to the SUS304BA plate after UV irradiation at 23°C may be in the range of, for example, 0.01 N / 10 mm to 0.45 N / 10 mm, 0.02 N / 10 mm to 0.35 N / 10 mm, 0.03 N / 10 mm to 0.25 N / 10 mm, and particularly preferably in the range of 0.01 N / 10 mm to 0.10 N / 10 mm.

[0116] The adhesive layer of the adhesive tape for semiconductor processing preferably has an adhesive strength of, for example, 0.45 N / 10 mm to 5.30 N / 10 mm before UV irradiation to a polished SUS304 steel plate (SUS304 steel plate polished in the same direction with #360 waterproof sandpaper) at 23°C, more preferably 0.60 N / 10 mm to 4.00 N / 10 mm, and even more preferably 0.90 N / 10 mm to 2.70 N / 10 mm.

[0117] In some embodiments, the adhesive layer of the adhesive tape for semiconductor processing has an adhesive strength (integrated UV light intensity: 300 mJ / cm²) after UV irradiation to a polished SUS304 steel plate at 23°C. ２The peeling angle (90 degrees, peeling speed (5 mm / sec)) may be, for example, 0.45 N / 10 mm or less, 0.35 N / 10 mm or less, 0.25 N / 10 mm or less, or 0.10 N / 10 mm or less. Furthermore, the adhesive strength to the polished SUS304 steel plate at 23°C after UV irradiation may be, for example, 0.01 N / 10 mm or more, 0.02 N / 10 mm or more, 0.03 N / 10 mm or more, or 0.04 N / 10 mm or more. In some preferred embodiments, the adhesive strength to the polished SUS304 steel sheet at 23°C after UV irradiation may be in the range of, for example, 0.01 N / 10 mm to 0.45 N / 10 mm, 0.02 N / 10 mm to 0.35 N / 10 mm, 0.03 N / 10 mm to 0.25 N / 10 mm, and particularly preferably in the range of 0.01 N / 10 mm to 0.10 N / 10 mm.

[0118] In some embodiments, the adhesive layer of the adhesive tape for semiconductor processing may have an adhesive strength to a Si wafer at 23°C before UV irradiation, for example, in the range of 0.50 N / 10 mm to 5.75 N / 10 mm, preferably 0.65 N / 10 mm to 4.30 N / 10 mm, and more preferably 1.00 N / 10 mm to 2.90 N / 10 mm.

[0119] In some embodiments, the adhesive layer of a semiconductor processing adhesive tape has an adhesive strength (integrated UV light intensity: 300 mJ / cm²) after UV irradiation to a Si wafer at 23°C. ２The peeling angle (90 degrees, peeling speed (5 mm / sec)) may be, for example, 0.35 N / 10 mm or less, 0.25 N / 10 mm or less, 0.15 N / 10 mm or less, or 0.10 N / 10 mm or less. Furthermore, the adhesive strength to the Si wafer after UV irradiation at 23°C may be, for example, 0.01 N / 10 mm or more, 0.02 N / 10 mm or more, 0.03 N / 10 mm or more, or 0.04 N / 10 mm or more. In some preferred embodiments, the adhesive strength to the Si wafer after UV irradiation at 23°C may be in the range of, for example, 0.01 N / 10 mm to 0.35 N / 10 mm, 0.02 N / 10 mm to 0.25 N / 10 mm, 0.03 N / 10 mm to 0.15 N / 10 mm, and particularly preferably in the range of 0.01 N / 10 mm to 0.10 N / 10 mm.

[0120] The above adhesive strength can be measured more specifically by the method described in the examples.

[0121] The adhesive layer of the adhesive tape for semiconductor processing may have a holding force against a polished SUS plate (SUS304 plate polished in the same direction with #360 waterproof sandpaper) at 40°C, for example, in the range of 0.15 mm (amount of displacement) to 1.40 mm, preferably 0.20 mm to 1.00 mm, and more preferably 0.25 mm to 0.70 mm. The above holding force can be measured more specifically by the method described in the examples.

[0122] The ball tack of the adhesive layer of the adhesive tape for semiconductor processing may be in the range of, for example, 2 to 25, preferably 3 to 19, more preferably 4 to 13, and particularly preferably 8 to 12. The above ball tack can be measured more specifically by the method described in the examples.

[0123] The method for manufacturing adhesive tapes for semiconductor processing is not particularly limited and can be manufactured by known methods. For example, an adhesive tape for semiconductor processing can be manufactured by a method that includes the steps of: preparing a release liner; preparing a solution of an adhesive composition which is a material for forming an adhesive layer (a coating solution for forming an adhesive layer); applying the prepared coating solution for the adhesive layer onto the release surface of the release liner and drying it to form an adhesive layer of a predetermined thickness; preparing a base film; laminating the base film onto the adhesive layer formed on the release liner; and crosslinking and curing the formed adhesive layer by aging it for 72 hours in an environment of 40°C, for example, to react an active energy ray curable acrylic adhesive polymer with a crosslinking agent (i.e., a step to obtain a crosslinked product of the adhesive composition).

[0124] A solution of the above adhesive composition (coating solution for forming the adhesive layer) can be prepared, for example, by uniformly mixing and stirring an acrylic adhesive polymer, a photopolymerization initiator, a crosslinking agent, and a diluent solvent, which are components of the adhesive layer. As the solvent, a general-purpose organic solvent such as toluene or ethyl acetate can be used.

[0125] The method of applying the adhesive layer-forming coating solution is not particularly limited, and can be applied using, for example, a die coater, comma coater (registered trademark), gravure coater, roll coater, reverse coater, etc. Furthermore, the drying conditions are not particularly limited, but it is preferable, for example, that the drying temperature be within the range of 80°C to 150°C and the drying time be within the range of 0.5 minutes to 5 minutes.

[0126] As an example of forming an adhesive layer on the base film, a method was given in which an adhesive layer-forming coating solution is applied to a release liner and dried, and then the base film is laminated onto the adhesive layer. However, a method of directly applying the adhesive layer-forming coating solution to the base film and drying it may also be used. From the viewpoint of stable production, the former method is preferred.

[0127] Adhesive tapes for semiconductor processing may be in the form of a roll or in the form of a stack of wide sheets. Alternatively, these forms of adhesive tapes for semiconductor processing may be cut to predetermined sizes to form sheets or tapes.

[0128] The present invention will be described in more detail by the following examples, but the present invention is not limited to these examples.

[0129] [Preparation of the adhesive composition] The materials used in the preparation of the adhesive composition are listed below.

[0130] The monomers used in the preparation of the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond are listed below.・BIO-BA: n-butyl acrylate with a biomass-derived butyl group [4 carbon atoms] at the ester end (bio-based carbon content: 57% by mass, homopolymer Tg: -54°C) ・BIO-OA: n-octyl acrylate with a biomass-derived octyl group [8 carbon atoms] at the ester end (bio-based carbon content: 71% by mass, homopolymer Tg: -44°C) ・BIO-2OA: 1-methylheptyl acrylate [also known as 2-octyl acrylate] with a biomass-derived 1-methylheptyl group [8 carbon atoms] at the ester end (bio-based carbon content: 73% by mass, homopolymer Tg: -44°C) ・BIO-LA: lauryl acrylate with a biomass-derived lauryl group [12 carbon atoms] at the ester end (biomass carbon content: 79% by mass, homopolymer Tg: -23°C) • BIO-STA: Stearyl acrylate having a biomass-derived stearyl group [18 carbon atoms] at the ester terminus (biomass carbon content: 85% by mass, homopolymer Tg: 30°C) • 2EHA: 2-ethylhexyl acrylate (homopolymer Tg: -70°C) • MA: Methyl acrylate (homopolymer Tg: 8°C) • MAA: Methacrylic acid (homopolymer Tg: 228°C) • AA: Acrylic acid (homopolymer Tg: 105°C) • HEA: 2-hydroxyethyl acrylate (homopolymer Tg: -15°C) • 4HBA: 4-hydroxybutyl acrylate (homopolymer Tg: -40°C) MOI: 2-Isocyanate ethyl methacrylate (Chemical name alternative: 2-methacryloyloxyethyl isocyanate, trade name: Karenz MOI, manufactured by Resonac Co., Ltd., molecular weight: 155.15, isocyanate group: 1 / molecule, double bond group: 1 / molecule)

[0131] Materials other than acrylic adhesive polymers are listed below.

[0132] - Urethane acrylate oligomer (weight-average molecular weight Mw: 1000, hydroxyl value: 1 mg KOH / g, number of carbon-carbon double bonds: 6 / molecule) - Photopolymerization initiator: Acyl phosphine oxide photopolymerization initiator (manufactured by IGM Resins B.V., trade name: Omnirad 819) - Crosslinking agent: TDI polyisocyanate crosslinking agent (manufactured by Soken Chemical Co., Ltd., trade name: Curing agent L-45K, solid content concentration: 45% by mass)

[0133] (Example 1) BIO-OA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-OA / MAA / HEA = 78.80% by mass / 1.20% by mass / 20.00% by mass (= 427.61 mmol / 13.94 mmol / 172.24 mmol). Using ethyl acetate as the solvent and azobisisobutyronitrile (AIBN) as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -37.2°C.

[0134] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0135] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 1 with a solids concentration of 31.00% by mass.

[0136] (Example 2) BIO-OA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-OA / MAA / HEA = 81.80% by mass / 1.20% by mass / 17.00% by mass (= 443.89 mmol / 13.94 mmol / 146.40 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -38.0°C.

[0137] Next, 16.00 parts by mass (103.13 mmol: 70.44 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 20.9 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0138] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 2 with a solids concentration of 31.00% by mass.

[0139] (Example 3) BIO-OA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-OA / MAA / HEA = 78.80% by mass / 1.20% by mass / 20.00% by mass (= 427.61 mmol / 13.94 mmol / 172.24 mmol), and a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization) using ethyl acetate as the solvent and AIBN as the initiator. The Tg of the obtained base polymer, calculated from Fox's formula, was -37.2°C.

[0140] Next, 10.00 parts by mass (64.45 mmol: 37.42 mol%) of MOI as an active energy ray reactive compound was added to 100.00 parts by mass of the solids content of this base polymer and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 55.0 mg KOH / g, solids acid value: 7.1 mg KOH / g, carbon-carbon double bond concentration: 0.59 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0141] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 3 with a solids concentration of 31.00% by mass.

[0142] (Example 4) BIO-OA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-OA / MAA / HEA = 82.50% by mass / 0.50% by mass / 17.00% by mass (= 447.69 mmol / 5.81 mmol / 146.40 mmol), and a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization) using ethyl acetate as the solvent and AIBN as the initiator. The Tg of the obtained base polymer, calculated from Fox's formula, was -38.9°C.

[0143] Next, 10.00 parts by mass (64.45 mmol: 44.03 mol%) of MOI as an active energy ray reactive compound was added to 100.00 parts by mass of the solids content of this base polymer and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 41.8 mg KOH / g, solids acid value: 3.0 mg KOH / g, carbon-carbon double bond concentration: 0.59 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0144] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 4 with a solids concentration of 31.00% by mass.

[0145] (Example 5) BIO-2OA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-2OA / MAA / HEA = 78.80% by mass / 1.20% by mass / 20.00% by mass (= 427.61 mmol / 13.94 mmol / 172.24 mmol). Using ethyl acetate as the solvent and azobisisobutyronitrile (AIBN) as the initiator, a solution of a hydroxyl-containing base polymer was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -37.2°C.

[0146] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 870,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0147] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 5 with a solids concentration of 31.00% by mass.

[0148] (Example 6) BIO-LA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-LA / MAA / HEA = 78.80% by mass / 1.20% by mass / 20.00% by mass (= 327.81 mmol / 13.94 mmol / 172.24 mmol), and a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization) using ethyl acetate as the solvent and AIBN as the initiator. The Tg of the obtained base polymer, calculated from Fox's formula, was -19.9°C.

[0149] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 850,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0150] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 6 with a solids concentration of 31.00% by mass.

[0151] (Example 7) BIO-LA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-LA / MAA / HEA = 92.80% by mass / 1.20% by mass / 6.00% by mass (= 386.06 mmol / 13.94 mmol / 51.67 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -21.0°C.

[0152] Next, 7.00 parts by mass (45.12 mmol: 87.32 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound. This was reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 850,000, solids hydroxyl value: 3.44 mg KOH / g, solids acid value: 7.3 mg KOH / g, carbon-carbon double bond concentration: 0.42 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0153] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 7 with a solids concentration of 31.00% by mass.

[0154] (Example 8) BIO-LA, 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-LA / 2EHA / MAA / HEA = 66.80% by mass / 13.00% by mass / 1.20% by mass / 19.00% by mass (= 277.89 mmol / 70.54 mmol / 13.94 mmol / 163.62 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -27.5°C.

[0155] Next, 16.00 parts by mass (103.13 mmol: 63.03 mol%) of MOI as an active energy ray reactive compound was added to 100.00 parts by mass of the solids content of this base polymer and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 850,000, solids hydroxyl value: 29.3 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0156] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 8 with a solids concentration of 31.00% by mass.

[0157] (Example 9) BIO-OA, 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-OA / 2EHA / MAA / HEA = 75.00% by mass / 3.00% by mass / 2.00% by mass / 20.00% by mass (= 406.99 mmol / 16.28 mmol / 23.23 mmol / 172.24 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -37.0°C.

[0158] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 11.2 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0159] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare adhesive composition 9 with a solids concentration of 31.00% by mass.

[0160] (Example 10) BIO-OA, BIO-STA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-OA / BIO-STA / MAA / HEA = 77.00% by mass / 1.00% by mass / 2.00% by mass / 20.00% by mass (= 417.84 mmol / 3.08 mmol / 23.23 mmol / 172.24 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -35.5°C.

[0161] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 880,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 11.2 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0162] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 10 with a solids concentration of 31.00% by mass.

[0163] (Example 11) BIO-OA, BIO-STA, 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to achieve a copolymerization ratio of BIO-OA / BIO-STA / 2EHA / MAA / HEA = 68.50% by mass / 5.00% by mass / 4.50% by mass / 2.00% by mass / 20.00% by mass (= 371.72 mmol / 15.418 mmol / 24.42 mmol / 23.23 mmol / 172.24 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -34.5°C.

[0164] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 880,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 11.2 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0165] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 11 with a solids concentration of 31.00% by mass.

[0166] (Example 12) BIO-OA, BIO-STA, BIO-BA, 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to achieve a copolymerization ratio of BIO-OA / BIO-STA / BIO-BA / 2EHA / MAA / HEA = 58.00% by mass / 10.00% by mass / 6.00% by mass / 4.00% by mass / 2.00% by mass / 20.00% by mass (= 314.74 mmol / 30.81 mmol / 32.56 mmol / 21.71 mmol / 23.23 mmol / 172.24 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -32.0°C.

[0167] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 870,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 11.2 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0168] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 12 with a solids concentration of 31.00% by mass.

[0169] (Example 13) BIO-OA, BIO-STA, BIO-BA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to achieve a copolymerization ratio of BIO-OA / BIO-STA / BIO-BA / MAA / HEA = 40.00% by mass / 15.00% by mass / 23.00% by mass / 2.00% by mass / 20.00% by mass (= 217.06 mmol / 46.22 mmol / 124.81 mmol / 21.71 mmol / 23.23 mmol / 172.24 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -29.5°C.

[0170] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 860,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 11.2 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0171] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 13 with a solids concentration of 31.00% by mass.

[0172] (Example 14) BIO-2OA, BIO-STA, MAA, and 4HBA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-2OA / BIO-STA / MAA / 4HBA = 36.90% by mass / 30.00% by mass / 3.10% by mass / 30.00% by mass (= 200.24 mmol / 92.44 mmol / 36.01 mmol / 208.04 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -19.9°C.

[0173] Next, 17.00 parts by mass (109.57 mmol: 52.67 mol%) of MOI as an active energy ray reactive compound was added to 100.00 parts by mass of the solids content of this base polymer and reacted with some of the hydroxyl groups of 4HBA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids concentration: 34.00% by mass, weight-average molecular weight Mw: 860,000, solids hydroxyl value: 17.3 mg KOH / g, solids acid value: 47.2 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0174] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 14 with a solids concentration of 31.00% by mass.

[0175] (Comparative Example 1) 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of 2EHA / MAA / HEA = 78.80% by mass / 1.20% by mass / 20.00% by mass (= 427.61 mmol / 13.94 mmol / 172.24 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -59.4°C.

[0176] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0177] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 15 with a solids concentration of 31.00% by mass.

[0178] (Comparative Example 2) 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of 2EHA / MAA / HEA = 81.80% by mass / 1.20% by mass / 17.00% by mass (= 443.89 mmol / 13.94 mmol / 146.40 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -60.8°C.

[0179] Next, 16.00 parts by mass (103.13 mmol: 70.44 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 20.9 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0180] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 16 with a solids concentration of 31.00% by mass.

[0181] (Comparative Example 3) 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of 2EHA / MAA / HEA = 78.80% by mass / 1.20% by mass / 20.00% by mass (= 427.61 mmol / 13.94 mmol / 172.24 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -59.4°C.

[0182] Next, 10.00 parts by mass (64.45 mmol: 37.42 mol%) of MOI as an active energy ray reactive compound was added to 100.00 parts by mass of the solids content of this base polymer and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 55.0 mg KOH / g, solids acid value: 7.1 mg KOH / g, carbon-carbon double bond concentration: 0.59 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0183] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 17 with a solids concentration of 31.00% by mass.

[0184] (Comparative Example 4) 2EHA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of 2EHA / MAA / HEA = 82.50% by mass / 0.50% by mass / 17.00% by mass (= 447.69 mmol / 5.81 mmol / 146.40 mmol). Using ethyl acetate as the solvent and AIBN as the initiator, a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization). The Tg of the obtained base polymer, calculated from Fox's formula, was -61.7°C.

[0185] Next, 10.00 parts by mass (64.45 mmol: 44.03 mol%) of MOI as an active energy ray reactive compound was added to 100.00 parts by mass of the solids content of this base polymer and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 890,000, solids hydroxyl value: 41.8 mg KOH / g, solids acid value: 3.00 mg KOH / g, carbon-carbon double bond concentration: 0.59 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0186] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad 819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 18 with a solids concentration of 31.00% by mass.

[0187] (Comparative Example 5) BIO-OA, MA, and AA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-OA / MA / AA = 39.00% by mass / 59.00% by mass / 2.00% by mass (= 211.63 mmol / 589.29 mmol / 27.74 mmol), and a solution of the base polymer was synthesized by free radical polymerization (solution polymerization) using ethyl acetate as the solvent and AIBN as the initiator. The Tg of the obtained base polymer, calculated from Fox's formula, was -13.6°C.

[0188] Next, the acrylic adhesive polymer synthesized above was blended in the following proportions: 147.06 parts by mass of urethane acrylate oligomer and 2.65 parts by mass (4.03 mmol) of curing agent L-45K per 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 19 with a solids concentration of 31.00% by mass.

[0189] (Comparative Example 6) BIO-STA, MAA, and HEA were prepared as copolymer monomer components. These copolymer monomer components were mixed to a copolymerization ratio of BIO-STA / MAA / HEA = 78.80% by mass / 1.20% by mass / 20.00% by mass (= 242.80 mmol / 13.94 mmol / 172.24 mmol), and a solution of a base polymer having hydroxyl groups was synthesized by free radical polymerization (solution polymerization) using ethyl acetate as the solvent and AIBN as the initiator. The Tg of the obtained base polymer, calculated from Fox's formula, was 21.1°C.

[0190] Next, 16.00 parts by mass (103.13 mmol: 59.87 mol% relative to HEA) of MOI was added to 100.00 parts by mass of the solids content of this base polymer as an active energy ray reactive compound, and reacted with some of the hydroxyl groups of HEA to synthesize a solution of an acrylic adhesive polymer having carbon-carbon double bonds in its side chains (solids content concentration: 34.00% by mass, weight-average molecular weight Mw: 830,000, solids hydroxyl value: 33.4 mg KOH / g, solids acid value: 6.7 mg KOH / g, carbon-carbon double bond concentration: 0.89 mmol / g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bonds.

[0191] Next, the acrylic adhesive polymer synthesized above was mixed with 1.47 parts by mass of Omnirad819 and 0.13 parts by mass (0.20 mmol) of the curing agent L-45K in a ratio of solids to 100.00 parts by mass of solids. The mixture was then diluted with ethyl acetate and stirred to prepare an adhesive composition 20 with a solids content of 31.00% by mass.

[0192] [Bio-based carbon content] The bio-based carbon content of the nonvolatile components of the acrylic adhesive polymers synthesized in the above examples and comparative examples and the prepared adhesive compositions was calculated from the carbon isotope content with mass number 14, measured in accordance with ASTM D6866.

[0193] [Preparation of Adhesive Tape] A release-treated PET film with a thickness of 38 μm (manufactured by Nakamoto Pax Co., Ltd., product name "NS-38+A") was coated with an adhesive composition solution for forming the adhesive layer so that the thickness of the adhesive layer after drying would be 10 μm. The solvent was dried in a drying oven at 110°C at a speed of 1.0 m / min to form the adhesive layer, which was then laminated to a predetermined base film (manufactured by Gunze Corporation, product name "Funcrea DDZ", thickness 90 μm) and wound up. After that, the tape was aged at 23°C for 4 days to crosslink and cure the adhesive layer, thereby producing an adhesive tape having an adhesive layer containing crosslinked products of the adhesive composition.

[0194] [Evaluation Method] The adhesive tapes prepared using the adhesive compositions prepared in the examples and comparative examples were evaluated as follows. The results are shown in Tables 1 to 3.

[0195] <Adhesive Strength> (Adhesive strength to SUS304BA plate) The prepared adhesive tape was cut, and a test piece measuring 25 mm in width and 250 mm in length was taken.

[0196] - The adhesive surface of the adhesion strength test specimen was exposed before UV (ultraviolet) irradiation, and this adhesive surface was attached to a SUS304BA plate (bright annealed stainless steel plate, JIS G 4305). A 2000g roller was used to press the specimen back and forth at a speed of 5 mm / sec. After roller pressing, the specimen was left at 23°C for 20 to 40 minutes before the measurement test was performed. The adhesion strength was measured by continuously peeling the specimen at a speed of 5 mm / sec using a test apparatus (JIS B 7721) equipped with a 90° peeling jig.

[0197] - After UV irradiation, the adhesive surface of the adhesion strength test specimen was exposed, and this adhesive surface was attached to the SUS304BA plate. A roller with a mass of 2000 g was used to press it back and forth once at a speed of 5 mm / sec. After roller pressing, it was left at 23°C for 20 to 40 minutes before UV irradiation. The UV irradiation conditions were a high-pressure mercury lamp (center wavelength 365 nm) with an irradiation intensity of 70 mW / cm². ２ , irradiation amount 300mJ / cm ２ Subsequently, the adhesive strength was measured by continuously peeling the samples at a speed of 5 mm / sec using a test apparatus (JIS B 7721) equipped with a 90° peeling jig.

[0198] (Adhesion to polished SUS plate) The adhesive surface of the test piece was exposed and attached to a polished SUS plate (SUS304 steel plate polished in the same direction with #360 waterproof sandpaper) before and after UV irradiation, in the same manner as the measurement of "adhesion to SUS304BA plate".

[0199] (Adhesion to Si wafer) The adhesive surface of the test piece was exposed and attached to the mirror surface of the Si wafer. Except for this, the adhesion before and after UV irradiation was measured in the same manner as the measurement of "adhesion to SUS304BA plate".

[0200] <Holding Force> A test specimen measuring 25 mm in width and 150 mm in length was taken. The holding force against a polished stainless steel plate was measured. Specifically, the test specimen was backed with film tape, then attached to the polished stainless steel plate over an area of ​​25 mm x 25 mm, and pressed down once back and forth with a 2000 g roller at a speed of 5 mm / sec. After that, it was left at 40°C for 20 to 40 minutes. Next, the test plate and test specimen were mounted on a test stand so that they hung vertically. A 9.8 N weight was attached to the end of the test specimen, and the amount of displacement of the test specimen was measured after being stored in a 40°C environment for 24 hours.

[0201] <Ball Tack> A test specimen measuring 25 mm in width and 300 mm in length was taken. In accordance with the "inclined ball tack" method described in JIS Z 0237 (2009), a ball rolling device equipped with an inclined plate at an inclination angle of 30° and a runway length of 100 mm was used, and a ball specified in JIS B 1501 was rolled. The ball number of the longest ball that stopped within the 100 mm measurement range was taken as the ball tack value.

[0202] <Presence or absence of adhesive residue on Si wafers> After measuring the adhesive strength following UV irradiation of Si wafers, the Si wafers were observed and visually checked for the presence or absence of stain-like or clump-like adhesive residue.

[0203] The results of each evaluation are shown in Tables 1 to 3. In the adhesive strength measurement results, if no adhesive strength was detected to the adherend, it was indicated as "Measurement not possible".

[0204]

[0205]

[0206]

[0207] As shown in Tables 1 and 2, the adhesive tapes of Examples 1 to 14, which have an adhesive layer containing an adhesive composition mainly composed of an acrylic adhesive polymer with a bio-based carbon content of 50% by mass or more, exhibited sufficient adhesive strength to SUS304BA plates, polished SUS plates, and Si wafers before UV irradiation, and a reduction in adhesive strength was observed after UV irradiation. Furthermore, it was found that the adhesive strength before and after UV irradiation was comparable to that of the conventional adhesive tapes of Comparative Examples 1 to 4, which have a non-biomass adhesive layer containing an adhesive composition mainly composed of an acrylic adhesive polymer with a bio-based carbon content of 0% by mass as shown in Table 3. Therefore, it was confirmed that the adhesive compositions of Examples 1 to 14, which have reduced dependence on fossil resource-based materials, are active energy ray-curable, peelable adhesive compositions suitable for dicing tape applications. In addition, no adhesive residue was observed on the Si wafer when the adhesive tapes of Examples 1 to 14 were peeled off after UV irradiation. In contrast, as shown in Table 3, in the adhesive tape of Comparative Example 5, which had an adhesive layer containing an active energy ray curable release adhesive composition comprising an acrylic adhesive polymer with a bio-based carbon content of less than 50% by mass (34.3% by mass) and no active energy ray reactive carbon-carbon double bonds in its side chains, and a urethane acrylate oligomer, adhesive residue due to low molecular weight oligomers was observed on the Si wafer when the adhesive tape was peeled off after UV irradiation. Furthermore, although the bio-based carbon content of the acrylic adhesive polymer in the adhesive tape of Comparative Example 6 was 50% by mass or more, the Tg of its base polymer did not satisfy the desired value, so it had almost no function as an adhesive tape, and the adhesive strength could not be measured.

Claims

1. An active energy ray curable release adhesive composition comprising an acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond, a photopolymerization initiator, and a crosslinking agent, wherein the acrylic adhesive polymer is a polymer having an active energy ray-reactive carbon-carbon double bond in the side chain of a (meth)acrylic acid ester copolymer, the (meth)acrylic acid ester copolymer comprises, as constituent units of the copolymer, constituent units derived from an alkyl (meth)acrylate ester having a biomass-derived alkyl group at the ester terminus and constituent units derived from a monomer having a functional group, and having a glass transition temperature (Tg) of -18°C or lower, and the bio-based carbon content of the acrylic adhesive polymer is 50% by mass or more.

2. The active energy ray curable release adhesive composition according to claim 1, wherein the alkyl (meth)acrylate ester having a biomass-derived alkyl group at its ester terminus comprises an alkyl (meth)acrylate ester having a biomass-derived alkyl group with 4 to 12 carbon atoms at its ester terminus.

3. The active energy ray curable release adhesive composition according to claim 2, wherein the alkyl (meth)acrylate ester having a biomass-derived alkyl group at its ester terminus further comprises an alkyl (meth)acrylate ester having a biomass-derived alkyl group with 14 to 18 carbon atoms at its ester terminus.

4. The active energy ray curable release adhesive composition according to claim 2, wherein the content of constituent units derived from (meth)acrylate alkyl esters having a biomass-derived alkyl group having 4 to 12 carbon atoms at the ester terminus is in the range of 65.0% by mass or more and 93.9% by mass or less, relative to the total constituent units contained in the (meth)acrylate ester copolymer, and the content of constituent units derived from monomers having the functional group is in the range of 6.1% by mass or more and 35.0% by mass or less, relative to the total constituent units contained in the (meth)acrylate ester copolymer.

5. The active energy ray curable peelable adhesive composition according to claim 3, wherein the content of constituent units derived from (meth)acrylate alkyl esters having a biomass-derived alkyl group having 4 to 12 carbon atoms at the ester terminus is in the range of 36.9% by mass or more and 93.8% by mass or less with respect to the total constituent units contained in the (meth)acrylate ester copolymer, the content of constituent units derived from (meth)acrylate alkyl esters having a biomass-derived alkyl group having 14 to 18 carbon atoms at the ester terminus is in the range of 0.1% by mass or more and 30.0% by mass or less with respect to the total constituent units contained in the (meth)acrylate ester copolymer, and the content of constituent units derived from monomers having a functional group is in the range of 6.1% by mass or more and 33.1% by mass or less with respect to the total constituent units contained in the (meth)acrylate ester copolymer.

6. The active energy ray curable peelable adhesive composition according to any one of claims 1 to 5, wherein the monomer having the functional group includes a hydroxyl group-containing monomer and a carboxyl group-containing monomer.

7. The active energy ray curable release adhesive composition according to claim 4, wherein the monomer having the functional group is a hydroxyl group-containing monomer and a carboxyl group-containing monomer, the content of the constituent units derived from the hydroxyl group-containing monomer is in the range of 6.0% by mass or more and 30.0% by mass or less with respect to the total constituent units contained in the (meth)acrylic acid ester copolymer, and the content of the constituent units derived from the carboxyl group-containing monomer is in the range of 0.1% by mass or more and 5.0% by mass or less with respect to the total constituent units contained in the (meth)acrylic acid ester copolymer.

8. The active energy ray curable release adhesive composition according to claim 5, wherein the monomer having the functional group is a hydroxyl group-containing monomer and a carboxyl group-containing monomer, the content of the constituent units derived from the hydroxyl group-containing monomer is in the range of 6.0% by mass or more and 30.0% by mass or less with respect to the total constituent units contained in the (meth)acrylic acid ester copolymer, and the content of the constituent units derived from the carboxyl group-containing monomer is in the range of 0.1% by mass or more and 3.1% by mass or less with respect to the total constituent units contained in the (meth)acrylic acid ester copolymer.

9. The active energy ray curable peelable adhesive composition according to any one of claims 2 to 8, wherein the alkyl (meth)acrylate ester having a biomass-derived alkyl group having 4 to 12 carbon atoms at its ester terminus is an alkyl (meth)acrylate ester having a biomass-derived alkyl group having 4 to 8 carbon atoms at its ester terminus.

10. The active energy ray curable release adhesive composition according to any one of claims 1 to 9, wherein the acrylic adhesive polymer has an active energy ray reactive carbon-carbon double bond concentration in the range of 0.30 mmol / g or more and 1.30 mmol / g or less.

11. The active energy ray curable release adhesive composition according to any one of claims 1 to 10, wherein the content of the acrylic adhesive polymer is 85% by mass or more on a solid content basis relative to the entire active energy ray curable release adhesive composition.

12. An adhesive tape for semiconductor processing comprising an adhesive layer containing a crosslinked material of the active energy ray curable peelable adhesive composition according to any one of claims 1 to 11.

13. The adhesive layer of the semiconductor processing adhesive tape is subjected to ultraviolet irradiation of a SUS304BA plate at 23°C (integrated ultraviolet light intensity: 300 mJ / cm²). ２ The semiconductor processing adhesive tape according to claim 12, wherein the adhesive strength at a peeling angle of 90 degrees and a peeling speed of 5 mm / sec is in the range of 0.01 N / 10 mm or more and 0.45 N / 10 mm or less.

14. An article manufactured using the active energy ray curable release adhesive composition or a crosslinked product thereof according to any one of claims 1 to 11.

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