JP2022156388A - Workpiece processing sheet - Google Patents

Abstract

To provide a workpiece processing sheet which has excellent adhesiveness between a substrate and an adhesive layer while exhibiting excellent antistatic properties.SOLUTION: There is provided a workpiece processing sheet 1 which comprises a substrate 11 having a layer containing an antistatic agent and an adhesive layer 12 formed from an adhesive composition comprising an acrylic polymer (A) in which an active energy ray-curable group is introduced into the side chain and an isocyanate-based crosslinking agent (B), wherein the content of the crosslinking agent is 2 pts.mass or more and 10 pts.mass or less, the polymer (A) is obtained by reacting a (meth)acrylic acid ester polymer (AP) having a functional group with an active energy ray-curable group-containing compound (A3) in the presence of an organometallic catalyst and the polymer (AP) contains at least one of a predetermined (meth)acrylic acid alkyl ester (A1) and an alkoxy alkyl group-containing (meth)acrylic acid ester (A2).SELECTED DRAWING: Figure 1

Description

The present invention relates to a work processing sheet used for processing a work such as a semiconductor wafer.

Semiconductor wafers made of silicon, gallium arsenide, etc. and various types of packages are manufactured in a state of large diameter, cut into chips (diced), separated (picked up), and then transferred to the next process, the mounting process. At this time, the workpiece such as a semiconductor wafer is subjected to back grinding, dicing, cleaning, and the like while being laminated on an adhesive sheet having a base material and an adhesive layer (hereinafter sometimes referred to as a "workpiece processing sheet"). Processing such as drying, expanding, picking up, and mounting is performed.

The work processing sheet is peeled off from the processed work after a predetermined treatment process is completed. At this time, static electricity called separation electrification is generated between the work processing sheet and the adherend. There is Such static electricity causes dust and the like to adhere to workpieces and devices, and causes destruction of workpieces and the like. Therefore, work processing sheets are required to have antistatic properties.

Patent Documents 1 and 2 disclose the use of a base material containing a predetermined antistatic agent for the purpose of providing an antistatic work processing sheet.

JP 2014-207355 A JP 2008-244377 A

By the way, as the work processing sheet, a sheet having an adhesive layer composed of an active energy ray-curable adhesive is sometimes used. In this case, the adhesive layer may be irradiated with active energy rays after the work is processed on the work processing sheet and before the processed work is separated from the work processing sheet. The pressure-sensitive adhesive layer irradiated with active energy rays is cured, thereby reducing the adhesion to the workpiece after processing. Therefore, it is possible to easily separate the work after processing from the work processing sheet.

However, the pressure-sensitive adhesive layer cured by irradiation with active energy rays may lose adhesion not only to the workpiece after processing but also to the base material. In particular, the adhesion to the base material containing the antistatic agent as disclosed in Patent Documents 1 and 2 is significantly reduced, and when separating the work after processing from the work processing sheet, the base material There is a problem that the pressure-sensitive adhesive layer is easily peeled off.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a work processing sheet which exhibits excellent antistatic properties and which exhibits excellent adhesion between a substrate and an adhesive layer. aim.

To achieve the above object, firstly, the present invention provides a work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, wherein the substrate comprises the adhesive a surface layer located proximal to the adhesive layer, a back layer located distal to the adhesive layer, and an intermediate layer located between the surface layer and the back layer, At least one of the surface layer, the intermediate layer and the back layer contains an antistatic agent, and the pressure-sensitive adhesive layer comprises an acrylic polymer (A) having active energy ray-curable groups introduced into side chains and an isocyanate. composed of an active energy ray-curable pressure-sensitive adhesive formed from a pressure-sensitive adhesive composition containing a cross-linking agent (B), and the content of the isocyanate-based cross-linking agent (B) in the pressure-sensitive adhesive composition is 2 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the acrylic polymer (A), and the acrylic polymer (A) contains an organic tin compound, a zirconium complex, a zinc complex and a zirconium-containing metal soap. In the presence of at least one organometallic catalyst selected from, a (meth)acrylic acid ester polymer (AP) having a functional group and an active energy ray-curable group having a functional group capable of reacting with the functional group It is obtained by reacting with the containing compound (A3), and the (meth)acrylic acid ester polymer (AP), as a monomer unit constituting the polymer, has a glass transition temperature (Tg) as a homopolymer. is −20° C. or less and the alkyl group has 4 or less carbon atoms (meth)acrylic acid alkyl ester (A1), and the glass transition temperature (Tg) as a homopolymer is −20° C. or less, and Provided is a work processing sheet comprising at least one alkoxyalkyl group-containing (meth)acrylic acid ester (A2) in which the alkoxyalkyl group has 4 or less carbon atoms (Invention 1).

The work processing sheet according to the above invention (invention 1) has the above-mentioned three layers as a substrate, and one of the layers contains an antistatic agent, thereby exhibiting excellent antistatic properties. On the other hand, if the pressure-sensitive adhesive layer satisfies the above conditions, the adhesion between the substrate and the pressure-sensitive adhesive layer is excellent even after the pressure-sensitive adhesive layer is cured by irradiation with active energy rays. .

In the above invention (Invention 1), the surface layer and the back layer contain the antistatic agent, and the intermediate layer does not contain the antistatic agent, or the intermediate layer contains the surface It is preferable that the antistatic agent is contained in a smaller content (unit: mass %) than each of the layer and the back layer (Invention 2).

In the above inventions (inventions 1 and 2), the antistatic agent is preferably a polyether polyolefin block copolymer (invention 3).

In the above inventions (Inventions 1 to 3), the organometallic catalyst is the organotin compound, and the content of the organotin compound in the adhesive composition is 100 parts by mass of the acrylic polymer (A). On the other hand, it is preferably 0.001 parts by mass or more and less than 0.13 parts by mass (Invention 4).

In the above inventions (Inventions 1 to 4), the surface layer preferably has a thickness of 1 μm or more and 10 μm or less (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferably a dicing sheet (Invention 6).

The work processing sheet according to the present invention exhibits excellent antistatic properties and also exhibits excellent adhesion between the substrate and the pressure-sensitive adhesive layer.

1 is a cross-sectional view of a work processing sheet according to an embodiment of the present invention; FIG.

Embodiments of the present invention will be described below.
FIG. 1 shows a cross-sectional view of a work processing sheet according to one embodiment. A work processing sheet 1 shown in FIG. 1 includes a substrate 11 and an adhesive layer 12 laminated on one side of the substrate 11 .

As shown in FIG. 1, the base material 11 includes a surface layer 111 located proximal to the adhesive layer 12, a back layer 113 located distal to the adhesive layer 12, and a surface layer 111 and an intermediate layer 112 positioned between the back layer 113 . In the substrate 11, at least one layer of the surface layer 111, intermediate layer 112 and back layer 113 contains an antistatic agent.

As described above, the work processing sheet 1 according to the present embodiment has excellent antistatic properties by providing the base material 11 with the layer containing the antistatic agent. Therefore, it is possible to satisfactorily suppress the release electrification when the release sheet and the work are separated from the work processing sheet 1 .

Furthermore, in the work processing sheet 1 according to the present embodiment, the pressure-sensitive adhesive layer 12 contains an acrylic polymer (A) having active energy ray-curable groups introduced into side chains and an isocyanate-based cross-linking agent (B). It is composed of an active energy ray-curable adhesive formed from an adhesive composition that can be used.

The content of the isocyanate cross-linking agent (B) in the adhesive composition is 2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic polymer (A).

In addition, the acrylic polymer (A) is a (meth)acrylic polymer having a functional group in the presence of at least one organometallic catalyst selected from organic tin compounds, zirconium complexes, zinc complexes and zirconium-containing metal soaps. It is obtained by reacting an acid ester polymer (AP) with an active energy ray-curable group-containing compound (A3) having a functional group capable of reacting with the functional group.

Furthermore, the (meth)acrylic acid ester polymer (AP) has a glass transition temperature (Tg) of −20° C. or less as a homopolymer as a monomer unit constituting the polymer, and the number of carbon atoms in the alkyl group is A (meth)acrylic acid alkyl ester (A1) having 4 or less, and an alkoxyalkyl having a homopolymer glass transition temperature (Tg) of −20° C. or less and an alkoxyalkyl group having 4 or less carbon atoms. It contains at least one group-containing (meth)acrylic acid ester (A2).

Since the adhesive layer 12 of the work processing sheet 1 according to the present embodiment satisfies the above conditions, the adhesion between the substrate 11 and the adhesive layer 12 is excellent. In particular, even after curing the adhesive layer 12 by irradiation with active energy rays, the substrate 11 and the adhesive layer 12 exhibit high adhesion. Therefore, when separating the processed work from the work processing sheet 1, even if the adhesive layer 12 is cured by irradiation with active energy rays, the adhesive layer 12 is separated from the base material 11. The workpiece after machining can be separated satisfactorily from the workpiece machining sheet 1.

In general, when a wafer is diced on the work processing sheet 1, the adhesive layer 12 may be cut together with the wafer. In this case, when the obtained chip is picked up from the work processing sheet 1, the possibility that the cut adhesive layer 12 is attached to the chip is very likely to be picked up. However, according to the work processing sheet 1 according to the present embodiment, even in such a case, adhesion of the adhesive layer 12 to the chip can be suppressed satisfactorily.

1. Structure of Work Processing Sheet (1) Base Material The base material 11 in the present embodiment includes the surface layer 111, the intermediate layer 112 and the back layer 113, as described above. The composition of these layers is not particularly limited as long as at least one of surface layer 111, intermediate layer 112 and back layer 113 contains an antistatic agent.

Materials other than the antistatic agent in each layer constituting the base material 11 are not particularly limited as long as the layers can be formed. For example, it is preferable to use a resin. In particular, it is preferable to use at least one of polyolefin resin and thermoplastic elastomer as the main material from the viewpoint of easily exhibiting the performance required for the work processing sheet, such as expandability and suppression of cutting chips. Note that the surface layer 111 and the back layer 113 may have different compositions, or may have the same composition.

(1-1) Polyolefin-based resin Specific examples of the above-described polyolefin-based resin are not particularly limited. In this specification, the term "polyolefin resin" refers to a homopolymer or copolymer of an olefin as a monomer, or a copolymer of an olefin and a molecule other than an olefin as a monomer, and the olefin unit in the resin after polymerization. A resin in which the mass ratio of the part based on is 1.0% by mass or more.

The polymer constituting the polyolefin resin may be linear or may have a side chain. Moreover, the polymer may have an aromatic ring or an aliphatic ring.

Examples of the olefin monomer constituting the polyolefin resin include olefin monomers having 2 to 8 carbon atoms, α-olefin monomers having 3 to 18 carbon atoms, and olefin monomers having a cyclic structure. . Examples of olefin monomers having 2 to 8 carbon atoms include ethylene, propylene, 2-butene and octene. α-olefin monomers having 3 to 18 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1 - Octadecene and the like are exemplified. Examples of olefin monomers having a cyclic structure include norbornene, cyclopentadiene, cyclohexadiene, dicyclopentadiene, tetracyclododecene, and derivatives thereof.

Polyolefin-based resins can be used singly or in combination of two or more.

Among the specific examples of the polyolefin resin described above, it is preferable to use at least one of polyethylene containing ethylene as a main polymer unit and polypropylene containing propylene as a main polymer unit.

As the polypropylene, it is preferable to use, for example, homopolypropylene, random polypropylene and block polypropylene. These can be used individually by 1 type or in mixture of 2 or more types. In particular, it is preferable to use a mixture of homopolypropylene and random polypropylene.

As the homopolypropylene, random polypropylene and block polypropylene described above, commercial products on the market may be used. Examples of commercially available homopolypropylene include the product name "Prime Polypro E111G", the product name "Prime Polypro E-100GV", the product name "Prime Polypro E-100GPL", and the product name "Prime Polypro E-200GP" and the like. Examples of commercial products of random polypropylene include "Prime Polypro B221WA", "Prime Polypro B241", "Prime Polypro E222", and "Prime Polypro E-333GV", all manufactured by Prime Polymer Co., Ltd. etc. Examples of commercially available block polypropylene include "Prime Polypro E701G", "Prime Polypro E702G", and "Prime Polypro E702MG" all manufactured by Prime Polymer.

The above polyethylene may be any of high density polyethylene, medium density polyethylene, low density polyethylene, ultra low density polyethylene and linear low density polyethylene, or a mixture of two or more thereof.

In particular, as the polyethylene, it is preferable to use low-density polyethylene, and examples of commercially available products thereof include the product name "Novatec LL" manufactured by Mitsubishi Chemical Corporation, the Neo-Zex series and Ultra-Zex series manufactured by Prime Polymer Co., Ltd., and the like. is mentioned.

When any of the layers constituting the base material 11 contains a polyolefin resin, the content of the polyolefin resin in the layer is preferably 10% by mass or more, particularly 15% by mass or more. Preferably, it is 20% by mass or more. The content is preferably 100% by mass or less, particularly preferably 95% by mass or less, and more preferably 90% by mass or less. When the content of the polyolefin-based resin is within the above range, the work processing sheet 1 according to the present embodiment tends to have better expandability.

(1-2) Thermoplastic Elastomer The above-described thermoplastic elastomer is not particularly limited as long as it is other than the above-mentioned polyolefin-based resin and enables formation of the base material 11 . Examples of thermoplastic elastomers include olefin elastomers, rubber elastomers, urethane elastomers, styrene elastomers, acrylic elastomers, and vinyl chloride elastomers. These may be used alone or in combination of two or more.

Among the elastomers described above, olefinic elastomers are preferable from the viewpoint that they are easy to obtain good expandability. In particular, at least one of surface layer 111 and back layer 113 preferably contains an olefin elastomer. As used herein, the term "olefin-based elastomer" refers to a copolymer containing structural units derived from an olefin or its derivative (olefin-based compound), and having rubber-like elasticity in a temperature range including room temperature. , means a material having thermoplasticity.

Examples of olefinic elastomers include ethylene/propylene copolymers, ethylene/α-olefin copolymers, propylene/α-olefin copolymers, butene/α-olefin copolymers, ethylene/propylene/α-olefin copolymers. At least one resin selected from the group consisting of polymers, ethylene/butene/α-olefin copolymers, propylene/butene/α-olefin copolymers and ethylene/propylene/butene/α-olefin copolymers things are mentioned. Among these, ethylene/propylene copolymers are preferred.

When any of the layers constituting the base material 11 contains an olefinic elastomer, the content of the olefinic elastomer in the layer is preferably 1% by mass or more, particularly 10% by mass or more. Preferably, it is 15% by mass or more. The content is preferably 90% by mass or less, particularly preferably 80% by mass or less, and further preferably 70% by mass or less. When the content of the olefinic elastomer is within the above range, the work processing sheet 1 according to the present embodiment can easily obtain better expandability.

Moreover, it is also preferable to use a styrene-based elastomer from the viewpoint of easily obtaining good expandability. In particular, intermediate layer 112 preferably contains a styrene-based elastomer. As used herein, the term "styrene-based elastomer" refers to a copolymer containing structural units derived from styrene or its derivative (styrene-based compound), and having rubber-like elasticity in a temperature range including room temperature. , means a material having thermoplasticity.

Styrene-based elastomers include styrene-conjugated diene copolymers and styrene-olefin copolymers, among which styrene-conjugated diene copolymers are preferred. Specific examples of styrene-conjugated diene copolymers include styrene-butadiene copolymers, styrene-butadiene-styrene copolymers (SBS), styrene-butadiene-butylene-styrene copolymers, styrene-isoprene copolymers, Unhydrogenated styrene-conjugated diene copolymer such as styrene-isoprene-styrene copolymer (SIS), styrene-ethylene-isoprene-styrene copolymer; styrene-ethylene/propylene-styrene copolymer (SEPS: styrene- Hydrogenated styrene-conjugated diene copolymer such as isoprene-styrene copolymer), styrene-ethylene-butylene-styrene copolymer (SEBS: hydrogenated styrene-butadiene copolymer), etc. be able to. The styrene-based thermoplastic elastomer may be hydrogenated (hydrogenated) or unhydrogenated, but hydrogenated is preferred. Among these, hydrogenated styrene-conjugated diene copolymers are preferred, and styrene-ethylene-butylene-styrene copolymers (SEBS) are particularly preferred, from the viewpoint of easily obtaining good expandability.

The content (styrene ratio) of structural units derived from styrene or styrene compounds in the styrene elastomer is preferably 1% by mass or more, particularly preferably 5% by mass or more, and further preferably 10% by mass or more. is preferably The content of the structural unit is preferably 80% by mass or less, particularly preferably 70% by mass or less, further preferably 60% by mass or less, from the viewpoint of film-forming properties. This makes it easier to achieve excellent expandability.

When any of the layers constituting the base material 11 contains a styrene-based elastomer, the content of the styrene-based elastomer in the layer is preferably 1% by mass or more, particularly 10% by mass or more. Preferably, it is 15% by mass or more. The content is preferably 90% by mass or less, particularly preferably 80% by mass or less, and further preferably 70% by mass or less. When the content of the styrene-based elastomer is within the above range, the work processing sheet 1 according to the present embodiment can easily obtain better expandability.

(1-3) Antistatic agent The antistatic agent in the present embodiment is not particularly limited, and known agents can be used. Examples of antistatic agents include low-molecular-weight antistatic agents and high-molecular-weight antistatic agents. A polymer-type antistatic agent is preferable from the viewpoint that it is easy to achieve higher adhesion between the base material 11 and the pressure-sensitive adhesive layer 12 .

Polymer type antistatic agents include copolymers having polyether units such as polyether ester amides and polyether polyolefin block copolymers. These copolymers include alkali metal salts and alkaline earth metal salts. A metal salt such as ionic liquid may be contained. Among these, polyether polyolefin block copolymers are preferable from the viewpoint of achieving sufficient antistatic properties and easily achieving high adhesion between the substrate 11 and the pressure-sensitive adhesive layer 12 .

A polyether polyolefin block copolymer is a copolymer comprising units of polyether moieties and polyolefin moieties. Since the polyether portion exhibits ionic conductivity, antistatic properties are exhibited, and the polyolefin portion provides excellent dispersibility with the polyolefin resin.

Examples of commercially available polyether polyolefin block copolymers include the product names "Perestat 300", "Perestat 230", "Pelectron PVH", "Pelectron PVL", "Pelectron HS", and "Pelectron HS", all of which are manufactured by Sanyo Kasei Co., Ltd. Perestat 201”, “Plectron UC” and the like, Sanko Kagaku Kogyo Co., Ltd. under the product name “Sunkonol TBX-310”, and the like.

In the substrate 11 of the present embodiment, as described above, at least one layer of the surface layer 111, the intermediate layer 112, and the back layer 113 contains an antistatic agent. It is preferable to contain an agent. As a result, the work processing sheet 1 according to the present embodiment tends to have an excellent antistatic property, and the separation electrification when the release sheet and the work are separated from the work processing sheet 1 can be suppressed satisfactorily. can be done.

Although the intermediate layer 112 may also contain an antistatic agent, the intermediate layer 112 does not contain an antistatic agent or contains an intermediate layer from the viewpoint of easily suppressing the generation of chips during dicing. Layer 112 preferably contains an antistatic agent in a smaller content (unit: mass %) than each of surface layer 111 and back layer 113 . As described above, the intermediate layer 112 that does not contain an antistatic agent or that contains a small amount of antistatic agent is present between the surface layer 111 and the back layer 113, so that the dicing blade can be placed in the intermediate layer during dicing. When reaching the layer 112, the generation of chips from the intermediate layer 112 can be well suppressed.

The content of the antistatic agent in the surface layer 111 is preferably 3% by mass or more, particularly preferably 5% by mass or more, further preferably 10% by mass or more. When the content of the antistatic agent is 3% by mass or more, it becomes easy to exhibit good antistatic properties. The content of the antistatic agent in the surface layer 111 is preferably 40% by mass or less, particularly preferably 35% by mass or less, and further preferably 30% by mass or less. When the content of the antistatic agent is 40% by mass or less, the adhesiveness between the substrate 11 and the pressure-sensitive adhesive layer 12 can be more easily improved.

The content of the antistatic agent in the back layer 113 is preferably 10% by mass or more, particularly preferably 20% by mass or more, further preferably 30% by mass or more. When the content of the antistatic agent is 10% by mass or more, it becomes easy to exhibit good antistatic properties. Also, the content of the antistatic agent in the back layer 113 is preferably 50% by mass or less, particularly preferably 45% by mass or less, further preferably 40% by mass or less. When the content of the antistatic agent is 50% by mass or less, the adhesiveness between the substrate 11 and the pressure-sensitive adhesive layer 12 can be more easily improved.

As described above, the intermediate layer 112 does not contain an antistatic agent, or the intermediate layer 112 has a smaller content (unit: mass %) than each of the surface layer 111 and the back layer 113. It preferably contains an inhibitor. When intermediate layer 112 contains an antistatic agent, the content in intermediate layer 112 is preferably 10% by mass or less, particularly preferably 5% by mass or less, and further preferably 3% by mass or less. Preferably. When the content of the antistatic agent in the intermediate layer 112 is 10% by mass or less, it becomes easy to suppress the generation of chips. In addition, as a lower limit of the said content, 0.01 mass % or more may be sufficient, for example.

(1-4) Acid-denatured resin Each layer constituting the base material 11 preferably contains an acid-denatured resin. In particular, the surface layer 111 preferably contains an acid-modified resin. As used herein, the term "acid-modified resin" means a polymer chain to which a structure derived from an acid component is added. The structure derived from the acid component may be in the form of an acid anhydride or may have a carboxy group. When the surface layer 111 contains the acid-modified resin as described above, the adhesion between the base material 11 and the adhesive layer 12 is further improved, and the adhesive can be further suppressed from remaining on the chip side during pickup. can.

Examples of the main chain of the acidic resin preferably include ethylene-acrylic copolymers such as ethylene-(meth)acrylic acid copolymers and ethylene-(meth)acrylic acid ester copolymers. Such a resin facilitates improving the adhesion between the surface layer 111 and the adhesive layer 12 . In this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.

As the (meth)acrylic acid ester, an alkyl (meth)acrylic acid ester having an alkyl group of 1 to 4 carbon atoms is preferable. For example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate and the like are preferably mentioned. Among them, ethyl (meth)acrylate is more preferable, and ethyl acrylate is particularly preferable.

The content of the structure derived from (meth)acrylic acid ester in the ethylene-(meth)acrylic acid ester copolymer is preferably 1% by mass or more, particularly preferably 3% by mass or more. Also, the content is preferably 20% by mass or less, particularly preferably 15% by mass or less, and further preferably 10% by mass or less.

In order to acid-modify the resin, it is preferable to react the resin with an unsaturated carboxylic acid. Examples of unsaturated carboxylic acids include maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, and aconitic anhydride. , norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, and the like. These can be used individually by 1 type or in combination of 2 or more types. Among the above, maleic anhydride is particularly preferable from the viewpoint of adhesion with the pressure-sensitive adhesive layer 12 .

The amount of the acid component (the amount of the structure derived from the acid component) in the acid-modified resin is preferably 1% by mass or more, particularly preferably 2% by mass or more. Moreover, the amount of the acid component is preferably 7% by mass or less, and particularly preferably 5% by mass or less. Adhesion between the surface layer 111 and the pressure-sensitive adhesive layer 12 is further improved when the amount of the acid component is within the above range.

When the surface layer 111 contains an acid-modified resin, the content of the acid-modified resin in the surface layer 111 is preferably 5% by mass or more, and particularly preferably 10% by mass or more. This further improves the adhesion between the surface layer 111 and the adhesive layer 12 . Also, the content is preferably 30% by mass or less, particularly preferably 25% by mass or less, and further preferably 20% by mass or less.

(1-5) Other Components The layer that constitutes the base material 11 may contain components other than those described above. In particular, the resin composition may contain components that are commonly used as substrates for work processing sheets.

Examples of such components include various additives such as flame retardants, plasticizers, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers. Although the content of these additives is not particularly limited, it is preferably within a range in which the base material exhibits the desired functions.

(1-6) Surface Treatment of Base Material The surface of the base material 11 on which the adhesive layer 12 is to be laminated is subjected to primer treatment, corona treatment, plasma treatment, roughening treatment, etc. in order to increase adhesion with the adhesive layer 12 . A surface treatment such as surface treatment (matte treatment) may be applied. Examples of the roughening treatment include embossing, sandblasting, and the like. Among these, corona treatment is preferred.

(1-7) Method for manufacturing base material The method for manufacturing the base material 11 in the present embodiment is not particularly limited. Solution methods and the like can be used. Among these, from the viewpoint of efficiently producing a base material, it is preferable to adopt the melt extrusion method, and it is particularly preferable to adopt the T-die method.

Further, when the base material 11 is produced by a melt extrusion method, the components constituting each layer are individually kneaded, and the resulting kneaded product is directly or once pellets are produced, and then a known extruder is used to produce a plurality of layers. are simultaneously extruded to form a film.

(1-8) Physical Properties of Substrate The surface resistivity of the surface of the substrate 11 facing the surface layer 111 is preferably 1.0×10 ¹³ Ω/□ or less, particularly 1.0×10 ¹² Ω. /□ or less, and more preferably 1.0×10 ¹¹ Ω/□ or less. When the surface resistivity is 1.0×10 ¹³ Ω/□ or less, the work processing sheet 1 according to the present embodiment tends to have good antistatic properties. The lower limit of the surface resistivity is not particularly limited, and may be, for example, 1.0×10 ⁸ Ω/□ or more, particularly 1.0×10 ⁹ Ω/□ or more. The details of the method for measuring the surface resistivity are as described in the test examples described later.

The thickness of the surface layer 111 in this embodiment is preferably 1 μm or more, particularly preferably 2 μm or more, and further preferably 4 μm or more. Also, the thickness of the surface layer 111 is preferably 10 μm or less, particularly preferably 8 μm or less, and further preferably 4 μm or less. When the thickness of the surface layer 111 is within the above range, the work processing sheet 1 can easily achieve excellent expandability, and the work processing sheet 1 can easily be provided with desired performance. Further, when the thickness of the surface layer 111 is 10 μm or less, the adhesiveness between the substrate 11 and the pressure-sensitive adhesive layer 12 can be easily improved.

The thickness of the intermediate layer 112 in the present embodiment is preferably 40 μm or more, particularly preferably 50 μm or more, further preferably 60 μm or more. Also, the thickness of the intermediate layer 112 is preferably 100 μm or less, particularly preferably 90 μm or less, further preferably 80 μm or less. When the thickness of the intermediate layer 112 is within the above range, the work processing sheet 1 can easily achieve excellent expandability, and the work processing sheet 1 can easily be provided with desired performance.

The thickness of the back layer 113 in this embodiment is preferably 2 μm or more, particularly preferably 4 μm or more, and further preferably 8 μm or more. Also, the thickness of the back layer 113 is preferably 40 μm or less, particularly preferably 30 μm or less, further preferably 25 μm or less. When the thickness of the back surface layer 112 is within the above range, the work processing sheet 1 can easily achieve excellent expandability, and the work processing sheet 1 can easily be provided with desired performance.

(2) Adhesive Layer As described above, the adhesive layer 12 in the present embodiment contains an acrylic polymer (A) having active energy ray-curable groups introduced into side chains and an isocyanate cross-linking agent (B). It is composed of an active energy ray-curable adhesive formed from an adhesive composition.

(2-1) Acrylic polymer (A) having active energy ray-curable groups introduced into side chains
As described above, the acrylic polymer (A) having active energy ray-curable groups introduced into side chains contains at least one organic metal selected from organic tin compounds, zirconium complexes, zinc complexes and zirconium-containing metal soaps. In the presence of a catalyst, a (meth)acrylic acid ester polymer (AP) having a functional group is reacted with an active energy ray-curable group-containing compound (A3) having a functional group capable of reacting with the functional group. It is what you get.

The (meth)acrylic acid ester polymer (AP) has a glass transition temperature (Tg) of −20° C. or less as a homopolymer as a monomer unit constituting the polymer, and the number of carbon atoms in the alkyl group is A (meth)acrylic acid alkyl ester (A1) having 4 or less, and an alkoxyalkyl having a homopolymer glass transition temperature (Tg) of −20° C. or less and an alkoxyalkyl group having 4 or less carbon atoms. At least one group-containing (meth)acrylic acid ester (A2) is included.

An adhesive obtained by the (meth)acrylic acid ester polymer (AP) containing at least one of the (meth)acrylic acid alkyl ester (A1) and the alkoxyalkyl group-containing (meth)acrylic acid ester (A2) However, even when cured by irradiation with active energy rays, good adhesion to the substrate can be maintained. In addition, the glass transition temperature (Tg) in the present specification is a calculated value obtained from the Fox formula.

Examples of the (meth)acrylic acid alkyl ester (A1) include n-butyl acrylate (Tg = -54°C), ethyl acrylate (Tg = -22°C), and isobutyl acrylate (Tg = -26°C). etc. Among these, it is preferable to use n-butyl acrylate.

When the (meth)acrylic acid ester polymer (AP) contains the (meth)acrylic acid alkyl ester (A1), the (meth)acrylic acid alkyl ester (A1) in the (meth)acrylic acid ester polymer (AP) ) is preferably 30% by mass or more, particularly preferably 40% by mass or more, further preferably 50% by mass or more. When the above ratio is 30% by mass or more, the resulting pressure-sensitive adhesive can maintain better adhesion to the substrate 11 . The above proportion is preferably 90% by mass or less, particularly preferably 80% by mass or less, further preferably 70% by mass or less. When the above ratio is 90% by mass or less, it becomes easy to secure the ratio of other desired monomers, and the pressure-sensitive adhesive obtained tends to have desired performance.

Examples of the alkoxyalkyl group-containing (meth)acrylic acid ester (A2) include methoxymethyl acrylate (Tg=-50°C). Among these, it is preferable to use methoxymethyl acrylate.

When the (meth)acrylic acid ester polymer (AP) contains the alkoxyalkyl group-containing (meth)acrylic acid ester (A2), the alkoxyalkyl group-containing (meth)acrylic acid ester polymer (AP) in the (meth)acrylic acid ester polymer (AP) ) The proportion of the structural portion derived from the acrylic acid ester (A2) is preferably 5% by mass or more, particularly preferably 10% by mass or more, and further preferably 15% by mass or more. When the above ratio is 5% by mass or more, the resulting pressure-sensitive adhesive can maintain better adhesion to the base material 11 . The above proportion is preferably 70% by mass or less, particularly preferably 60% by mass or less, further preferably 50% by mass or less. When the above ratio is 70% by mass or less, it becomes easy to secure the ratio of other desired monomers, and the pressure-sensitive adhesive obtained tends to have desired performance.

The (meth)acrylic acid ester polymer (AP) also preferably contains a functional group-containing monomer having a reactive functional group. The functional group can be used for reaction with the active energy ray-curable group-containing compound (A3) described above.

The functional group-containing monomer preferably has a reactive functional group capable of reacting with the functional group of the active energy ray-curable group-containing compound (A3). Examples of the functional group include a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, an epoxy group, etc. Among them, a hydroxyl group or a carboxyl group is preferable, and a hydroxyl group is particularly preferable. When using the isocyanate-based cross-linking agent (B), the reactive functional group of the functional group-containing monomer preferably reacts with the isocyanate-based cross-linking agent (B).

When a monomer having a hydroxyl group (hydroxyl group-containing monomer) is used as the functional group-containing monomer, examples thereof include hydroxyalkyl (meth)acrylates, and specific examples thereof include 2-hydroxyethyl (meth)acrylate. , 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate etc. Among these, 2-hydroxyethyl (meth)acrylate is preferred. These may be used alone or in combination of two or more.

When a monomer having a carboxy group (carboxy group-containing monomer) is used as the functional group-containing monomer, examples thereof include ethylenically unsaturated carboxylic acids, specific examples of which include acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and the like.

When the (meth)acrylic acid ester polymer (AP) contains a functional group-containing monomer, the mass ratio of the structural portion derived from the functional group-containing monomer in the (meth)acrylic acid ester polymer (AP) is 10% by mass or more. is preferably 15% by mass or more, and more preferably 20% by mass or more. Moreover, the ratio is preferably 70% by mass or less, particularly preferably 60% by mass or less, and further preferably 50% by mass or less. When the ratio of the mass of the structural portion derived from the functional group-containing monomer is within the above range, the active energy ray-curable group-containing compound ( The introduction amount of A3) can be set within a suitable range. Further, when the isocyanate-based cross-linking agent (B) is used to react the functional group-containing monomer and the isocyanate-based cross-linking agent (B), the degree of cross-linking by the isocyanate-based cross-linking agent (B), that is, the gel content The ratio can be set within a suitable range, and physical properties such as the cohesive strength of the pressure-sensitive adhesive layer 12 can be easily controlled.

The (meth)acrylic acid ester polymer (AP) may be obtained by copolymerizing other monomers together with the above-mentioned monomers. For example, the (meth)acrylic acid ester polymer (AP) may contain other (meth)acrylic acid alkyl esters other than the (meth)acrylic acid alkyl ester (A1) as monomer units constituting the polymer. good

The other (meth)acrylic acid alkyl ester preferably has an alkyl group with 1 to 18 carbon atoms, particularly preferably 1 to 4 carbon atoms.

Specific examples of the other (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl methacrylate, propyl (meth)acrylate, n-butyl methacrylate, isobutyl methacrylate, and n (meth)acrylate. -pentyl, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate , palmityl (meth)acrylate, stearyl (meth)acrylate, and the like. Among these, methyl methacrylate is preferred. These may be used alone or in combination of two or more.

When the (meth)acrylic acid ester polymer (AP) contains the other (meth)acrylic acid alkyl ester, the (meth)acrylic acid ester polymer (AP) derived from the other (meth)acrylic acid alkyl ester The mass ratio of the structural portion is preferably 1% by mass or more, particularly preferably 5% by mass or more, and further preferably 10% by mass or more. Moreover, the ratio is preferably 60% by mass or less, particularly preferably 50% by mass or less, and further preferably 40% by mass or less. When the ratio of the mass of the structural portion derived from the other (meth)acrylic acid alkyl ester is within the above range, the pressure-sensitive adhesive obtained tends to have desired performance.

In addition, the (meth)acrylic acid ester polymer (AP) includes, as monomer units constituting the polymer, other alkoxyalkyl group-containing (meth)acrylic acid esters other than the alkoxyalkyl group-containing (meth)acrylic acid ester (A2). It may also contain an acrylic acid ester. Examples thereof include methoxymethyl methacrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, ethoxyethyl (meth)acrylate and the like.

Furthermore, the (meth)acrylic acid ester polymer (AP) includes, as a monomer unit constituting the polymer, a (meth)acrylic acid ester having an aliphatic ring such as cyclohexyl (meth)acrylate; (meth)acrylic acid; (Meth) acrylic acid ester having an aromatic ring such as phenyl; N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone and other nitrogen-containing heterocyclic monomers; ) non-crosslinkable acrylamide such as acrylamide and N,N-dimethyl(meth)acrylamide; non-crosslinkable such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate (meth)acrylic acid ester having a tertiary amino group of; vinyl acetate; styrene and the like.

The polymerization form of the (meth)acrylate polymer (AP) may be a random copolymer or a block copolymer. Moreover, the polymerization method is not particularly limited, and polymerization can be performed by a general polymerization method such as a solution polymerization method.

On the other hand, the active energy ray-curable group-containing compound (A3) includes a functional group capable of reacting with the functional group of the (meth)acrylic acid ester polymer (AP), and a carbon-carbon dicarboxylic acid that is cleaved by irradiation with an active energy ray. It contains an active energy ray-curable group containing a double bond.

Examples of the functional group capable of reacting with the functional group of the (meth)acrylic acid ester polymer (AP) include an isocyanate group and an epoxy group, among which an isocyanate group having high reactivity with a hydroxyl group is preferred.

A (meth)acryloyl group and the like are preferable as the active energy ray-curable group containing a carbon-carbon double bond. It is preferable that 1 to 5 carbon-carbon double bonds cleaved by irradiation with an active energy ray are present in one molecule of the active energy ray-curable group-containing compound (A3), and in particular 1 to 3 are present. is preferred.

Examples of active energy ray-curable group-containing compounds (A3) include 2-methacryloyloxyethyl isocyanate, 2-acryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1 , 1-(bisacryloyloxymethyl)ethyl isocyanate; an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth)acrylate; a diisocyanate compound or polyisocyanate compound, a polyol compound, and a hydroxyl acryloyl monoisocyanate compounds obtained by reaction with ethyl (meth)acrylate; Among these, 2-methacryloyloxyethyl isocyanate is particularly preferred. In addition, the active energy ray-curable group-containing compound (A3) may be used alone, or two or more thereof may be used in combination.

In the obtained acrylic polymer (A), the amount of the active energy ray-curable group-containing compound (A3) is 60 mol% or more with respect to the amount of functional groups possessed by the (meth)acrylic acid ester polymer (AP). is preferably 70 mol % or more. Also, the amount of the active energy ray-curable group-containing compound (A3) is preferably 99 mol % or less, particularly preferably 95 mol % or less, further preferably 90 mol % or less.

In preparing the acrylic polymer (A), the preparation of the (meth) acrylic acid ester polymer (AP), and the (meth) acrylic acid ester polymer (AP) and the active energy ray-curable group-containing compound (A3 ) can be carried out by a conventional method. In this reaction step, a reactive functional group derived from the functional group-containing monomer (A2) in the (meth)acrylic acid ester polymer (AP) and a functional group in the active energy ray-curable group-containing compound (A3) reacts with the group. As a result, an acrylic polymer (A) having an energy ray-curable group introduced into the side chain is obtained.

As described above, the reaction between the (meth)acrylate polymer (AP) and the active energy ray-curable group-containing compound (A3) is selected from organic tin compounds, zirconium complexes, zinc complexes and zirconium-containing metal soaps. in the presence of at least one organometallic catalyst. Since the acrylic polymer (A) is produced by the action of such an organometallic catalyst, the resulting pressure-sensitive adhesive exhibits superior adhesion to the substrate 11 .

Examples of the above organotin compounds include dibutyltin dilaurate (DBTDL), dioctyltin dilaurate (DOTDL), dibutyltin diacetate (DBTDA), dioctyltin diacetate (DOTDA), dioctyltin maleate (DOTTM), dibutyltin maleate ( DBTM) and the like. Among these, it is preferable to use dibutyltin dilaurate (DBTDL).

When an organic tin compound is used as the organometallic catalyst, the content of the organic tin compound in the adhesive composition is 0.001 parts by mass or more with respect to 100 parts by mass of the acrylic polymer (A). is preferred, particularly preferably 0.01 parts by mass or more, and more preferably 0.02 parts by mass or more. Also, the content is preferably less than 0.13 parts by mass, particularly preferably 0.1 parts by mass or less, and more preferably 0.07 parts by mass or less. When the organic tin compound is used within these ranges, the resulting pressure-sensitive adhesive exhibits superior adhesion to the substrate 11 .

Examples of the above zirconium complexes include zirconium (IV) acetylacetonate, zirconium acetate, zirconium (IV) isopropoxide isopropanol, zirconium (IV) ethoxide, zirconium (IV) butoxide, zirconium (IV) propoxide, zirconium acrylate, zirconium carboxyethyl acrylate and the like. Among these, it is preferable to use zirconium (IV) acetylacetonate.

When a zirconium complex is used as the organometallic catalyst, the content of the zirconium complex in the adhesive composition is preferably 0.001 parts by mass or more with respect to 100 parts by mass of the acrylic polymer (A). In particular, it is preferably at least 0.01 parts by mass, more preferably at least 0.02 parts by mass. In addition, the content is preferably 0.2 parts by mass or less, particularly preferably 0.15 parts by mass or less, and further preferably 0.1 parts by mass or less. When the zirconium complex is used within these ranges, the adhesive obtained exhibits superior adhesion to the substrate 11 .

Examples of the zinc complex include zinc acetylacetonate (II) monohydrate, zinc acetate, trifluoroacetic acid, zinc methacrylate, and the like. Among these, zinc (II) acetylacetone monohydrate is preferably used.

When a zinc complex is used as the organometallic catalyst, the content of the zinc complex in the adhesive composition is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the acrylic polymer (A). In particular, it is preferably at least 0.03 parts by mass, more preferably at least 0.05 parts by mass. Also, the content is preferably 0.5 parts by mass or less, particularly preferably 0.3 parts by mass or less, and further preferably 0.2 parts by mass or less. When the zinc complex is used within these ranges, the resulting pressure-sensitive adhesive exhibits superior adhesion to the base material 11 .

Examples of the zirconium-containing metal soap include zirconium (2-ethylhexanoic acid) oxide IV, zirconium octylate, zirconium laurate, and zirconium oleate. Among these, it is preferable to use (2-ethylhexanoic acid) zirconium oxide IV.

When a zirconium-containing metal soap is used as the organometallic catalyst, the content of the zirconium-containing metal soap in the adhesive composition is 0.01 parts by mass or more with respect to 100 parts by mass of the acrylic polymer (A). It is preferably 0.03 parts by mass or more, and more preferably 0.05 parts by mass or more. Moreover, the content is preferably 0.5 parts by mass or less, particularly preferably 0.3 parts by mass or less, and further preferably 0.15 parts by mass or less. When the zirconium-containing metal soap is used within these ranges, the resulting pressure-sensitive adhesive exhibits superior adhesion to the substrate 11 .

The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably 100,000 or more, particularly preferably 200,000 or more, further preferably 300,000 or more. Also, the weight average molecular weight (Mw) is preferably 1,200,000 or less, particularly preferably 1,000,000 or less, and further preferably 800,000 or less. When the weight-average molecular weight (Mw) of the acrylic polymer (A) is within the above range, the obtained pressure-sensitive adhesive can be easily adjusted to have a viscosity suitable for coating, and can easily exhibit suitable pressure-sensitive adhesive physical properties.

(2-2) isocyanate cross-linking agent (B)
As the isocyanate cross-linking agent (B), it is preferable to use a compound having two or more isocyanate groups per molecule. Specific examples include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate and pentamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. etc. Furthermore, these biuret bodies, isocyanurate bodies, adduct bodies and the like are included. Adducts include reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among these, it is preferable to use at least one of trimethylolpropane-modified hexamethylene diisocyanate and trimethylolpropane-modified tolylene diisocyanate.

The isocyanate-based cross-linking agent (B) can be used singly or in combination of two or more. In addition, other cross-linking agents may be used in combination with the isocyanate-based cross-linking agent (B). Examples of other cross-linking agents include epoxy compounds, metal chelate compounds, polyimine compounds such as aziridine compounds, melamine resins, urea resins, dialdehydes, methylol polymers, metal alkoxides, and metal salts.

The content of the isocyanate cross-linking agent (B) in the adhesive composition is 2 parts by mass or more, preferably 3 parts by mass or more, with respect to 100 parts by mass of the acrylic polymer (A), particularly It is preferably 4 parts by mass or more. The content is 10 parts by mass or less, preferably 9 parts by mass or less, and particularly preferably 8 parts by mass or less. When the content of the isocyanate-based cross-linking agent (B) is within the above range, the pressure-sensitive adhesive obtained exhibits superior adhesion to the substrate 11 .

(2-3) Photoinitiator (C)
When ultraviolet rays are used as the active energy ray for curing the active energy ray-curable adhesive, the adhesive composition preferably further contains a photopolymerization initiator (C). By containing the photopolymerization initiator (C) in this way, it is possible to efficiently polymerize and cure the acrylic polymer (A) having an energy ray-curable group introduced into the side chain, and the polymerization curing time is And the irradiation amount of active energy rays can be reduced.

Examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4 -diethylthioxanthone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenylsulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4,6-trimethyl benzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, oligo{2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, 2,2-dimethoxy -1,2-diphenylethan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one etc. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator (C) in the adhesive composition is 0.1 parts by mass or more with respect to 100 parts by mass of the acrylic polymer (A) having an energy ray-curable group introduced into the side chain. It is preferably 0.5 parts by mass or more. In addition, the content of the photopolymerization initiator (C) is preferably 10 parts by mass or less with respect to 100 parts by mass of the acrylic polymer (A) in which an energy ray-curable group is introduced in the side chain, particularly It is preferably 8 parts by mass or less.

(2-4) Other components Desired additives such as antistatic agents and tackifiers as long as they do not impair the above-described effects of the adhesive composition P of the present embodiment and the work processing adhesive sheet 1 of the present embodiment Additives, antioxidants, light stabilizers, softeners, fillers, and the like can be added. It should be noted that the later-described diluent solvent is not included in the additives constituting the adhesive composition P.

(2-5) Preparation of adhesive composition The adhesive composition in the present embodiment is prepared by producing an acrylic polymer (A), adding an isocyanate cross-linking agent (B ), and, if desired, the photopolymerization initiator (C) and an additive. At this time, if desired, a diluent solvent may be added to obtain a coating liquid of the adhesive composition.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; Alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

The concentration/viscosity of the coating liquid thus prepared is not particularly limited as long as it is within a range that allows coating, and can be appropriately selected according to the situation. For example, it is diluted so that the concentration of the adhesive composition is 10% by mass or more and 60% by mass or less. When obtaining the coating liquid, the addition of a diluent solvent or the like is not a necessary condition, and the diluent solvent may not be added as long as the viscosity of the adhesive composition allows coating. In this case, the adhesive composition becomes a coating liquid in which the polymerization solvent for the acrylic polymer (A) is used as the diluting solvent.

(2-6) Thickness of adhesive layer The thickness of the adhesive layer 12 in the present embodiment is preferably 1 μm or more, particularly preferably 3 μm or more, and further preferably 5 μm or more. . Also, the thickness of the adhesive layer 12 is preferably 70 μm or less, particularly preferably 30 μm or less, further preferably 15 μm or less. When the thickness of the pressure-sensitive adhesive layer 12 is within the range described above, the work processing sheet 1 according to the present embodiment can easily exhibit the desired adhesiveness, and the adhesion to the substrate 11 is excellent. become a thing.

(3) Release sheet In the work processing sheet 1 according to the present embodiment, the surface of the adhesive layer 12 opposite to the base material 11 (hereinafter sometimes referred to as "adhesive surface") is attached to the work. A release sheet may be laminated on the surface for the purpose of protecting the surface during the cleaning.

The configuration of the release sheet is arbitrary, and an example thereof is a plastic film subjected to release treatment with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, a silicone-based, fluorine-based, long-chain alkyl, rubber-based, or the like can be used.

The thickness of the release sheet is not particularly limited, and may be, for example, 16 μm or more and 250 μm or less.

(4) Others In the work processing sheet 1 according to the present embodiment, an adhesive layer may be laminated on the surface of the adhesive layer 12 opposite to the base material 11 . In this case, the work processing sheet 1 according to this embodiment can be used as a dicing/die bonding sheet. In the sheet, a work is attached to the surface of the adhesive layer opposite to the adhesive layer 12, and the adhesive layer is diced together with the work, thereby forming chips laminated with the adhesive layer separated into pieces. Obtainable. The chip can be easily fixed to a target on which the chip is mounted by means of the individualized adhesive layer. Examples of the material constituting the adhesive layer include those containing a thermoplastic resin and a low-molecular-weight thermosetting adhesive component, those containing a B-stage (semi-cured) thermosetting adhesive component, and the like. It is preferable to use

In addition, in the work processing sheet 1 according to the present embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer 12 . In this case, the work processing sheet 1 according to this embodiment can be used as a protective film-forming and dicing sheet. In such a sheet, a work is attached to the surface of the protective film-forming layer opposite to the pressure-sensitive adhesive layer 12, and the protective film-forming layer is diced together with the work to obtain individualized protective film-forming layers. Stacked chips can be obtained. As the work, one having a circuit formed on one side is preferably used. In this case, a protective film-forming layer is usually laminated on the side opposite to the side on which the circuit is formed. By curing the individualized protective film-forming layer at a predetermined timing, a protective film having sufficient durability can be formed on the chip. The protective film-forming layer is preferably made of an uncured curable adhesive.

2. Method for Manufacturing Work Processing Sheet A method for manufacturing the work processing sheet 1 according to the present embodiment is not particularly limited. For example, after forming the adhesive layer 12 on the release sheet, the work processing sheet 1 can be obtained by laminating one side of the substrate 11 on the side of the adhesive layer 12 opposite to the release sheet. preferable.

Formation of the adhesive layer 12 mentioned above can be performed by a well-known method. For example, a coating liquid containing an adhesive composition for forming the adhesive layer 12 and optionally a solvent or a dispersion medium is prepared. Then, the coating liquid is applied to the peelable surface of the release sheet (hereinafter sometimes referred to as “release surface”). Then, the adhesive layer 12 can be formed by drying the obtained coating film.

The application of the coating liquid described above can be performed by a known method, such as bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, and the like. The properties of the coating liquid are not particularly limited as long as the coating liquid can be applied. be. Moreover, the release sheet may be released as a process material, or may protect the pressure-sensitive adhesive layer 12 until it is attached to an adherend.

When the adhesive composition for forming the adhesive layer 12 contains the above-described cross-linking agent, by changing the drying conditions (temperature, time, etc.) or by separately providing heat treatment, It is preferable to promote a cross-linking reaction between the polymer component in the coating film and the cross-linking agent to form a cross-linked structure with a desired existence density in the pressure-sensitive adhesive layer 12 . Furthermore, in order to allow the cross-linking reaction described above to proceed sufficiently, after bonding the adhesive layer 12 and the base material 11 together, curing is performed, for example, by allowing the adhesive layer 12 to stand in an environment of 23° C. and a relative humidity of 50% for several days. good too.

3. Method of Using Work Processing Sheet The work processing sheet 1 according to this embodiment can be used for processing a work such as a semiconductor wafer. That is, after the adhesive surface of the work processing sheet 1 according to this embodiment is attached to the work, the work can be processed on the work processing sheet 1 . Depending on the processing, the work processing sheet 1 according to this embodiment is used as a back grinding sheet, a dicing sheet, an expanding sheet, a pick-up sheet, or the like. Examples of the workpiece include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

As described above, the work processing sheet 1 according to the present embodiment has excellent adhesion between the base material 11 and the adhesive layer 12, and when the processed work is separated from the work processing sheet 1, the adhesive layer 12 can be effectively suppressed from being peeled off from the base material 11 and adhering to the work. Therefore, among the above-described work processing sheets, the work processing sheet 1 according to the present embodiment is particularly suitable for use as a dicing sheet and a pick-up sheet.

Furthermore, the work processing sheet 1 according to the present embodiment has excellent antistatic properties, as described above. The work processing sheet 1 according to the present embodiment can suppress separation electrification when separating the release sheet and when separating the work.

When the work processing sheet 1 according to the present embodiment includes the above-described adhesive layer, the work processing sheet 1 can be used as a dicing/die bonding sheet. Further, when the work processing sheet 1 according to this embodiment includes the protective film forming layer described above, the work processing sheet 1 can be used as a protective film forming and dicing sheet.

In addition, since the adhesive layer 12 in the work processing sheet 1 according to the present embodiment is composed of the active energy ray-curable adhesive described above, the following active energy ray irradiation is performed during use. is also preferred. That is, when the processing of the work is completed on the work processing sheet 1 and the work after processing is separated from the work processing sheet 1, the adhesive layer 12 is irradiated with an active energy ray before the separation. preferably. As a result, the adhesive layer 12 is cured, the adhesive strength of the adhesive sheet to the work after processing is favorably lowered, and the work after processing can be easily separated.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, another layer is laminated between the substrate 11 and the adhesive layer 12 in the work processing sheet 1 according to the present embodiment, or on the surface of the substrate 11 opposite to the adhesive layer 12. may In addition, the surface of the surface layer 111 opposite to the intermediate layer 112, between the surface layer 111 and the intermediate layer 112, between the intermediate layer 112 and the back layer 113, and on the back layer 113 opposite to the intermediate layer 112 Other layers may be laminated on the side faces, respectively.

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Preparation of base material A]
Random polypropylene resin (manufactured by Japan Polypropylene Corporation, product name "Novatec FX3B") 45 parts by mass, olefin-based thermoplastic elastomer (manufactured by Japan Polypropylene Corporation, product name "Wellnex RFX4V") 16 parts by mass, acid-modified resin (SK functional polymer company) manufactured by Sanyo Kasei, product name "BONDINE LX4110", ethyl acrylate content: 5% by mass, acid component amount: 3% by mass) 15 parts by mass, and antistatic agent (manufactured by Sanyo Kasei Co., Ltd., product name "Pelectron PVH") 25 parts by mass After drying each part, they were kneaded in a twin-screw kneader to obtain pellets for the surface layer.

In addition, random polypropylene resin (manufactured by Japan Polypro Co., Ltd., product name "Novatec FX3B") 28 parts by mass, olefinic thermoplastic elastomer (manufactured by Japan Polypropylene Co., Ltd., product name "Wellnex RFX4V") 39 parts by mass, and styrene thermoplastic elastomer (Asahi Kasei Corporation, product name “Tuftec H1041”, styrene/ethylene/butylene/styrene copolymer, styrene ratio: 30 wt%) 33 masses are dried and then kneaded in a twin-screw kneader. to obtain intermediate layer pellets.

Furthermore, 70 parts by mass of an olefinic thermoplastic elastomer (manufactured by Japan Polypropylene, product name "Wellnex RFX4V") and 30 parts by mass of an antistatic agent (manufactured by Sanyo Kasei Co., Ltd., product name "Pelectron PVH") were each dried. After that, by kneading with a twin-screw kneader, pellets for the back layer were obtained.

Using the three types of pellets obtained as described above, coextrusion molding is performed using a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name “Laboplastomill”), and a surface layer with a thickness of 4 μm and a thickness of A substrate A having a three-layer structure in which an intermediate layer of 64 μm and a back layer of 12 μm in thickness were laminated in this order was obtained.

[Preparation of base material B and base material C]
Substrates B and substrates were prepared in the same manner as substrate A, except that pellets for each layer prepared by changing the composition as shown in Table 1 were used, and the thickness of each layer was changed as shown in Table 1. Material C was produced.

[Example 1]
(1) Preparation of adhesive composition 62 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate are polymerized by a solution polymerization method to form a functional group ( A (meth)acrylic acid ester polymer (AP) having a hydroxyl group) was obtained.

Subsequently, 2-methacryloyloxyethyl isocyanate (MOI) is added in an amount corresponding to 80 mol% with respect to 2-hydroxyethyl acrylate constituting the (meth)acrylic acid ester polymer (AP), and an organic Dibutyltin dilaurate (DBTDL) as a metal catalyst was added in an amount of 0.03 parts by mass with respect to 100 parts by mass of the (meth)acrylate polymer (AP). After that, reaction was carried out at 50° C. for 24 hours to obtain an acrylic polymer (A) in which side chains were introduced with active energy ray-curable groups. It was 500,000 when the acrylic polymer (A) in which an active energy ray-curable group was introduced into the side chain was measured by the method described later.

100 parts by mass (in terms of solid content, the same shall apply hereinafter) of the acrylic polymer (A) having an active energy ray-curable group introduced into the side chain obtained above, and 2-hydroxy-1 as a photopolymerization initiator -{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (manufactured by BASF, product name “Omnilad 127”) 2 parts by mass, 5.7 parts by mass of hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate HL") as an isocyanate-based cross-linking agent was mixed in a solvent to obtain a coating liquid of an adhesive composition.

(2) Formation of adhesive layer On the release surface of a release sheet (manufactured by Lintec, product name "SP-PET381031") consisting of a polyethylene terephthalate film with a thickness of 38 μm and a silicone-based release agent layer formed on one side , By applying the coating liquid of the adhesive composition obtained in the above step (2) and drying at 90 ° C. for 1 minute, a comma coater was used on the release sheet to form an adhesive layer with a thickness of 5 μm. A laminated body was obtained.

(3) Preparation of work processing sheet After applying corona treatment to the surface layer side surface of base material A prepared as described above, the corona treatment surface and the laminate obtained in the above step (2) adhere to each other. After bonding the surface of the agent layer side, the work processing sheet was obtained by storing for two weeks under an environment of a temperature of 23° C. and a relative humidity of 50%.

Here, the weight average molecular weight (Mw) described above is a weight average molecular weight in terms of standard polystyrene measured under the following conditions using gel permeation chromatography (GPC).
<Measurement conditions>
・ Measuring device: HLC-8320 manufactured by Tosoh Corporation
・ GPC column (passed in the following order): TSK gel superH-H manufactured by Tosoh Corporation
TSK gel super HM-H
TSK gel super H2000
・Measurement solvent: tetrahydrofuran ・Measurement temperature: 40°C

[Examples 2 to 7, Comparative Examples 1 to 2]
The type of base material, the composition of the acrylic polymer (A), the type and content of the organometallic catalyst, and the type and content of the isocyanate cross-linking agent (B) were changed as shown in Table 2. A work processing sheet was obtained in the same manner as in Example 1.

[Test Example 1] (Measurement of surface resistivity)
After the substrates produced in Examples and Comparative Examples were conditioned at 23° C. and 50% relative humidity for 24 hours, the surface resistivity of the surface layer side was measured using DIGITAL ELECTROMETER (manufactured by ADVANTEST). Measured at an applied voltage of 100V. Table 2 shows the results.

[Test Example 2] (Evaluation of Adhesion)
The pressure-sensitive adhesive layer of the work processing sheet obtained in Examples and Comparative Examples was exposed through the base material under a nitrogen atmosphere using an ultraviolet irradiation device (manufactured by Lintec, product name "RAD-2000"). The pressure-sensitive adhesive layer was cured by irradiating with ultraviolet rays (light amount: 160 mJ/cm ² ).

Subsequently, the adhesive layer exposed by peeling off the release sheet was subjected to a cross-cut test method according to JIS K5400, and the number of squares (out of 100) remaining without being peeled off from the substrate was measured. . Then, the adhesion was evaluated according to the criteria shown below. Table 2 shows the number of squares and the results.
A: The number of remaining squares was 100.
◯: The number of remaining squares was 80 to 99.
Δ: The number of remaining squares was 50 to 79.
x: The number of remaining squares was 0 to 49.

Details of abbreviations and the like in Table 1 are as follows.
<Organometallic catalyst>
DBTDL: dibutyltin dilaurate zirconium (IV) acetylacetonate: zirconium (IV) acetylacetonate (manufactured by Nihon Kagaku Sangyo Co., Ltd., product name “Nasem zirconium compound”)
(2-Ethylhexanoic acid) zirconium oxide IV: (2-ethylhexanoic acid) zirconium oxide IV (Fujifilm Wako Pure Chemical Industries, Ltd., product name “Bis(2-ethylhexanoic acid) zirconium oxide IV Mineral spirit solution (Zr: 12%)”)
Zinc acetylacetonate (II) monohydrate: Zinc acetylacetonate (II) monohydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name “zinc acetylacetonate (II) monohydrate”)
<Isocyanate-based cross-linking agent>
Coronate HL: trimethylolpropane-modified hexamethylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate HL")
Coronate L: Trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L")

As is clear from Table 2, the work processing sheets produced in Examples had excellent adhesion between the substrate and the adhesive layer even after the adhesive layer was cured by irradiation with active energy rays. .

The work processing sheet of the present invention can be suitably used for processing a work such as a semiconductor wafer.

DESCRIPTION OF SYMBOLS 1... Sheet for work processing 11... Base material 111... Surface layer 112... Intermediate layer 113... Back layer 12... Adhesive layer

Claims (6)

A work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate,
The substrate is positioned between a surface layer proximal to the adhesive layer, a back layer distal to the adhesive layer, and between the top layer and the back layer. an intermediate layer;
At least one layer of the surface layer, the intermediate layer and the back layer contains an antistatic agent,
The active energy ray-curable adhesive layer is formed from an adhesive composition containing an acrylic polymer (A) having an active energy ray-curable group introduced into a side chain and an isocyanate cross-linking agent (B). is composed of an adhesive of
The content of the isocyanate cross-linking agent (B) in the adhesive composition is 2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the acrylic polymer (A),
In the presence of at least one organometallic catalyst selected from organotin compounds, zirconium complexes, zinc complexes and zirconium-containing metal soaps, the acrylic polymer (A) is subjected to a (meth)acrylic acid ester having a functional group. It is obtained by reacting the polymer (AP) with an active energy ray-curable group-containing compound (A3) having a functional group capable of reacting with the functional group,
The (meth)acrylic acid ester polymer (AP) has a glass transition temperature (Tg) of −20° C. or less as a homopolymer as a monomer unit constituting the polymer, and the number of carbon atoms in the alkyl group is 4. (Meth)acrylic acid alkyl ester (A1) having the following and an alkoxyalkyl group having a glass transition temperature (Tg) of −20° C. or less as a homopolymer and having 4 or less carbon atoms in the alkoxyalkyl group A work processing sheet comprising at least one (meth)acrylic acid ester (A2). The surface layer and the back layer contain the antistatic agent,
The intermediate layer does not contain the antistatic agent, or the intermediate layer contains the antistatic agent in a content (unit: mass%) less than each of the surface layer and the back layer. 2. The work processing sheet according to claim 1, wherein the work processing sheet is . 3. The work processing sheet according to claim 1, wherein the antistatic agent is a polyether-polyolefin block copolymer. The organometallic catalyst is the organotin compound,
The content of the organic tin compound in the adhesive composition is 0.001 parts by mass or more and less than 0.13 parts by mass with respect to 100 parts by mass of the acrylic polymer (A). The work processing sheet according to any one of claims 1 to 3. The work processing sheet according to any one of claims 1 to 4, wherein the surface layer has a thickness of 1 µm or more and 10 µm or less. The work processing sheet according to any one of claims 1 to 5, which is a dicing sheet.

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