JP5996985B2 - Manufacturing method of pressure-sensitive adhesive sheet, and pressure-sensitive adhesive sheet obtained by the manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a pressure-sensitive adhesive sheet, and a pressure-sensitive adhesive sheet obtained by the production method.

  The pressure-sensitive adhesive sheet is used in various applications, for example, for fixing a semiconductor wafer in a semiconductor wafer processing step. As a material for forming the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, a polymer having a urethane bond is typically used. Urethane bonds can be formed by reacting hydroxyl groups with isocyanate groups. In this reaction for forming a urethane bond, organotin compounds such as dioctyltin dilaurate and dibutyltin dilaurate are generally used as a catalyst (for example, Patent Document 1). However, organotin compounds are known to have effects on the human body and the environment, and their use is restricted by REACH. Therefore, there is a need for a catalyst that can replace the organotin compound.

  However, since the effect varies depending on the catalyst, it is difficult to apply another catalyst as it is to the reaction process in which the organotin compound has been used so far. Therefore, when a new catalyst is used, the reaction process needs to be examined again. Further, when a catalyst replacing the organotin compound is used, there is a problem that the reaction efficiency is lowered.

JP 2010-24255 A

  The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to allow the reaction to proceed smoothly without using an organotin compound as a catalyst, and to achieve excellent production efficiency. It is to provide a method for manufacturing a sheet.

As a result of repeated studies, the present inventors have selected from zirconium, titanium, and aluminum as a catalyst for the reaction between a (meth) acrylic polymer having two or more hydroxyl groups in the side chain and a compound having an isocyanate group. By using an amine catalyst as a catalyst for the reaction of at least one metal complex with a (meth) acrylic polymer having a urethane bond and a compound having two or more isocyanate groups in one molecule, the conventional reaction It has been found that the above problems can be solved without changing the process.
That is, the method for producing a pressure-sensitive adhesive sheet according to the present invention comprises reacting a (meth) acrylic polymer having two or more hydroxyl groups in the side chain with a compound having an isocyanate group in the presence of the first catalyst, thereby forming a urethane bond. A step of forming a (meth) acrylic polymer having the urethane bond, and a reaction of the (meth) acrylic polymer having a urethane bond with a compound having two or more isocyanate groups in one molecule in the presence of a second catalyst. And forming a pressure-sensitive adhesive layer. The first catalyst is a complex of at least one metal selected from zirconium, titanium, and aluminum, and the second catalyst is an amine catalyst.
In a preferred embodiment, the first catalyst is a metal complex in which at least one metal selected from zirconium, titanium, and aluminum is chelated with acetylacetone.
In a preferred embodiment, the second catalyst is a tertiary diamine.
In a preferred embodiment, the compound having two or more isocyanate groups in one molecule is a compound having three or more isocyanate groups in one molecule.
In a preferred embodiment, the compound having an isocyanate group is 2-isocyanatoethyl (meth) acrylate.
According to another aspect of the present invention, an adhesive sheet is provided. This pressure-sensitive adhesive sheet is obtained by the above-described method for producing a pressure-sensitive adhesive sheet.

  According to the present invention, in the reaction between a (meth) acrylic polymer having two or more hydroxyl groups in the side chain and a compound having an isocyanate group, at least one selected from zirconium, titanium, and aluminum is used as the first catalyst. In the reaction of a metal complex with a (meth) acrylic polymer having a urethane bond and a compound having two or more isocyanate groups in one molecule, an amine-based catalyst is used as the second catalyst, so that an organotin compound is used as a catalyst. The reaction to form a urethane bond smoothly can be advanced without using. Moreover, in the manufacturing method of this invention, an adhesive sheet can be manufactured with the same manufacturing efficiency as the case where an organotin compound is used as a catalyst. Furthermore, these catalysts can produce a pressure-sensitive adhesive sheet by using the reaction step using the organotin compound as it is.

<A. Manufacturing method of pressure-sensitive adhesive sheet>
In the method for producing a pressure-sensitive adhesive sheet of the present invention, a (meth) acrylic polymer having two or more hydroxyl groups in the side chain is reacted with a compound having an isocyanate group in the presence of the first catalyst to have a urethane bond ( A step of forming a (meth) acrylic polymer (hereinafter referred to as a first reaction), a (meth) acrylic polymer having the urethane bond, and a compound having two or more isocyanate groups in one molecule; A step of forming a pressure-sensitive adhesive layer by reacting in the presence of a catalyst (hereinafter referred to as a second reaction). The first catalyst is a complex of at least one metal selected from zirconium, titanium, and aluminum. The second catalyst is an amine catalyst. By using the metal complex as the first catalyst and the amine catalyst as the second catalyst, the reaction for smoothly forming a urethane bond can be advanced without using an organotin compound as the catalyst. Moreover, an adhesive sheet can be manufactured with the same manufacturing efficiency as the case where an organotin compound is used as a catalyst. Furthermore, by using these catalysts, a pressure-sensitive adhesive sheet can be produced using the reaction step using an organotin compound as a catalyst as it is.

<A-1. First reaction>
In the first reaction, a (meth) acrylic polymer having a urethane bond is reacted with a (meth) acrylic polymer having two or more hydroxyl groups in the side chain in the presence of the first catalyst. Form. As described above, the first catalyst is a complex of at least one metal selected from zirconium, titanium, and aluminum. By using a complex of these metals as the first catalyst, the urethane bond forming reaction can proceed smoothly as in the case where the organotin compound is used as the catalyst.

<A-1-1-2 (meth) acrylic polymer having a hydroxyl group in the side chain>
The (meth) acrylic polymer having two or more hydroxyl groups in the side chain can be obtained by polymerizing any appropriate (meth) acrylic monomer. The (meth) acrylic polymer having two or more hydroxyl groups in the side chain is preferably obtained by copolymerizing a (meth) acrylic monomer having a hydroxyl group and a (meth) acrylic monomer having no hydroxyl group. Polymer. The (meth) acrylic polymer having two or more hydroxyl groups in the side chain may be used alone or in combination of two or more.

  Any appropriate (meth) acrylic monomer can be used as the (meth) acrylic monomer having a hydroxyl group. For example, (meth) acrylic acid hydroxyethyl ester, (meth) acrylic acid hydroxybutyl ester, (meth) acrylic acid hydroxyhexyl ester and the like (meth) acrylic acid hydroxyalkyl ester and the like can be mentioned.

  Any appropriate (meth) acrylic monomer can be used as the (meth) acrylic monomer having no hydroxyl group. For example, carbon such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isononyl (meth) acrylate, etc. Examples include (meth) acrylic acid alkyl esters having 1 to 20 alkyl groups, epoxy (meth) acrylate, (meth) acrylic acid, 2-methoxyethyl acrylate, and the like.

  The mixing ratio of the (meth) acrylic monomer having a hydroxyl group and the (meth) acrylic monomer having no hydroxyl group used for the polymerization of the (meth) acrylic polymer having two or more hydroxyl groups in the side chain is arbitrary. An appropriate ratio can be set. For example, the compounding ratio of the (meth) acrylic monomer having a hydroxyl group to the (meth) acrylic monomer having no hydroxyl group can be set to 20/80 to 5/95 by weight. If the compounding ratio of the (meth) acrylic monomer having a hydroxyl group and the (meth) acrylic polymer having no hydroxyl group is within the above range, the obtained (meth) acrylic polymer and the compound having an isocyanate group A sufficient urethane bond can be formed between the two.

  The (meth) acrylic polymer having two or more hydroxyl groups in the side chain may be any suitable other polymerizable with the (meth) acrylic monomer having the hydroxyl group and the (meth) acrylic monomer having no hydroxyl group. The monomer component may be copolymerized. Examples of the monomer polymerizable with a (meth) acrylic monomer having a hydroxyl group and a (meth) acrylic monomer having no hydroxyl group include monomers having a functional group such as an epoxy group, a carboxyl group, and an acid anhydride group. It is done. Specific examples include acrylonitrile, acryloylmorpholine, vinyl acetate and the like.

  The use amount of the above-mentioned (meth) acrylic monomer having a hydroxyl group and the above (meth) acrylic monomer having no hydroxyl group is preferably a (meth) acrylic polymer having two or more hydroxyl groups in the side chain. It is 20% by weight or less of the total amount of the monomer components used for polymerization.

  The (meth) acrylic polymer having two or more hydroxyl groups in the side chain can be obtained by any appropriate polymerization method. For example, using any appropriate polymerization initiator, in any appropriate solvent, the (meth) acrylic monomer having a hydroxyl group and the (meth) acrylic monomer having no hydroxyl group, and if necessary, these Is polymerized with other polymerizable monomers to obtain a (meth) acrylic polymer having two or more hydroxyl groups in the side chain.

  Examples of the solvent include ethyl acetate, toluene, n-butyl acetate, n-hexane, cyclohexane, methyl ethyl ketone, and methyl isobutyl ketone.

  Any appropriate thermal polymerization initiator can be used as the polymerization initiator. Examples thereof include organic peroxides and azo compounds. The usage-amount of a polymerization initiator can be set to arbitrary appropriate values. For example, it is 0.01 part by weight to 1.0 part by weight with respect to 100 parts by weight of the total amount of monomer components used for the polymerization of the (meth) acrylic polymer having two or more hydroxyl groups in the side chain.

<A-1-2. Compound having isocyanate group>
Any appropriate compound having an isocyanate group can be used as the compound having an isocyanate group. For example, (meth) acryloyl isocyanate, 2-isocyanatoethyl (meth) acrylate, m-isopropenyl-α, α-dimethylbenzyl isocyanate and the like can be mentioned. Only 1 type may be used for the compound which has an isocyanate group, and it may be used in combination of 2 or more type.

  The compound having an isocyanate group is preferably 2-isocyanatoethyl (meth) acrylate. When 2-isocyanatoethyl (meth) acrylate is used as the compound having an isocyanate group, the resulting (meth) acrylic polymer further has a polymerizable unsaturated bond group. Therefore, the pressure-sensitive adhesive layer of the obtained pressure-sensitive adhesive sheet can function as a radiation curable pressure-sensitive adhesive layer.

  A commercially available product may be used as the compound having an isocyanate group. Examples of commercially available products include “Karenz MOI”, “Karenz AOI”, “Karenz BEI”, and “Karenz MOI-EG” manufactured by Showa Denko KK.

  The amount of the compound having an isocyanate group is preferably 5 to 30 parts by weight, more preferably 7 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer having two or more hydroxyl groups in the side chain. ~ 20 parts by weight.

<A-1-3. First catalyst>
As described above, the first catalyst is a metal complex selected from zirconium, titanium, and aluminum. By using the metal complex as the first catalyst, a reaction for smoothly forming a urethane bond can be performed without using an organotin compound as the catalyst. Moreover, even when these metal complexes are used, a reaction for forming a urethane bond can be performed with the same reaction efficiency as when an organotin compound is used as a catalyst. Furthermore, zirconium, titanium, and aluminum are highly safe metals, and can be suitably used from the viewpoint of influence on the human body and the environment. These metal complexes may be used alone or in combination of two or more.

  Any appropriate complex can be used as the metal complex. Examples of zirconium complexes include zirconium tetraacetylacetonate and tetranormalbutoxyzirconium; titanium complexes include titanium tetraacetylacetonate, titanium tetra-2-ethylhexoxide, dibutoxytitanium bisacetylacetonate, and the like; aluminum complexes Examples thereof include aluminum monoacetylacetonate bis (ethylacetoacetate).

  The metal complex is preferably a chelate of the metal and acetylacetone. The metal complex of the said metal and acetylacetone has diketone as a ligand. For this reason, there is a strong electrical attraction to active hydrogen by metals and ketones, and even better catalytic ability can be exhibited and the urethanization reaction can proceed effectively. Furthermore, gelation in the polymerization process of the (meth) acrylic polymer having a urethane bond can be prevented.

  A commercial product may be used as the metal complex in which the metal and acetylacetone are chelated. Examples of the chelated zirconium complex include “Orgachix ZC” series such as “Orgachix ZC-150” manufactured by Matsumoto Fine Chemical Co., Ltd. Examples of the chelated titanium complex include “Orgatics TC” series such as “Orgatics TC-401” manufactured by Matsumoto Fine Chemical Co., Ltd. Examples of the chelated aluminum complex include “aluminum chelate” series such as “Aluminum Chelate D” manufactured by Kawaken Fine Chemical Co., Ltd.

  The amount of the first catalyst used is preferably 0.0001 to 1 part by weight with respect to 100 parts by weight of the total amount of the polymer component and / or monomer component used for the polymerization of the (meth) acrylic polymer having a urethane bond. More preferably, it is 0.001 part by weight to 0.5 part by weight, and further preferably 0.003 part by weight to 0.3 part by weight. When the usage-amount of a 1st catalyst is less than 0.0001 weight part, the reactivity of a urethanation reaction is low, and a long time may be required by the completion | finish of a 1st reaction. When the usage-amount of a 1st catalyst exceeds 1 weight part, the catalyst itself may act as a low molecular-weight component and may reduce the adhesion characteristic of the adhesive layer obtained.

<A-1-4. Reaction method>
The first reaction can be performed by any appropriate method. For example, it is performed as follows. In any appropriate reaction vessel, a (meth) acrylic polymer having two or more hydroxyl groups in the side chain, a compound having an isocyanate group, a first catalyst, and optionally two or more hydroxyl groups in the side chain It is carried out by adding a (meth) acrylic polymer and a compound having an isocyanate group, a polymerizable monomer, and any appropriate solvent, and allowing them to react under inflow of dry air.

  The reaction temperature of the first reaction can be set to any appropriate value. The said reaction temperature can be set to 40 to 65 degreeC, for example. The reaction temperature can be adjusted in any suitable heating means. An example of the heating means is a water bath. When the reaction temperature rises excessively by heating, the temperature can be adjusted by dropping the solvent used in the first reaction.

The reaction time of the first reaction is usually 6 hours to 24 hours. When the reaction time of the first reaction is within the above range, there is no difference in the time required for the reaction as compared with the case where an organotin compound is used as the catalyst. Therefore, an adhesive sheet can be manufactured without reducing manufacturing efficiency. The first reaction may be completed when the isocyanate group is no longer confirmed by confirming the presence or absence of the isocyanate group (specifically, the presence or absence of absorption at 2270 cm ⁻¹ ) using FT-IR.

  Examples of the solvent include toluene, ethyl acetate, n-butyl acetate, n-hexane, cyclohexane, methyl ethyl ketone, and methyl isobutyl ketone.

  The polymerization reaction of the (meth) acrylic polymer having a urethane bond may be performed continuously with the polymerization reaction of the (meth) acrylic polymer having two or more hydroxyl groups in the side chain. For example, the reaction solution containing the (meth) acrylic polymer having two or more hydroxyl groups in the side chain has a first catalyst, a compound having an isocyanate group, and, if necessary, two or more hydroxyl groups in the side chain ( It may be prepared by adding a (meth) acrylic polymer and a compound having an isocyanate group and a polymerizable monomer and reacting them.

<A-2. Second reaction>
In the second reaction, a (meth) acrylic polymer having a urethane bond and a compound having two or more isocyanate groups in one molecule are reacted in the presence of a second catalyst to form an adhesive layer of an adhesive sheet. To do.

<A-2-1. (Meth) acrylic polymer having urethane bond>
The (meth) acrylic polymer having a urethane bond is a polymer obtained by the first reaction. The (meth) acrylic polymer having a urethane bond may be used alone or in combination of two or more.

<A-2-2. Compound having two or more isocyanate groups in one molecule>
A compound having two or more isocyanate groups in one molecule can function as a crosslinking agent. The (meth) acrylic polymer having a urethane bond may contain an unreacted hydroxyl group in the first reaction. The pressure-sensitive adhesive layer is formed by reacting the hydroxyl group with an isocyanate group of a compound having two or more isocyanate groups in one molecule in the presence of the second catalyst. Any appropriate compound can be used as the compound having two or more isocyanate groups in one molecule. The compound having two or more isocyanate groups in one molecule is preferably a compound having three or more isocyanate groups in one molecule. Examples of the compound having two or more isocyanate groups in one molecule include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates and the like. Only one type of compound having two or more isocyanate groups in one molecule may be used, or two or more types may be used in combination.

  Examples of the aliphatic polyisocyanates include 1,2-ethylene diisocyanate; tetramethylene diisocyanate such as 1,2-tetramethylene diisocyanate, 1,3-tetramethylene diisocyanate, 1,4-tetramethylene diisocyanate; 1,2- Hexamethylene diisocyanate such as hexamethylene diisocyanate, 1,3-hexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, 1,5-hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,5-hexamethylene diisocyanate; 2 -Methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, lysine diisocyanate and the like.

  Examples of the alicyclic polyisocyanates include isophorone diisocyanate; cyclohexyl diisocyanate such as 1,2-cyclohexyl diisocyanate, 1,3-cyclohexyl diisocyanate, 1,4-cyclohexyl diisocyanate; 1,2-cyclopentyl diisocyanate, 1,3- Examples include cyclopentyl diisocyanate such as cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and the like.

  Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, 4,4′-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4′-diisocyanate, 2,2′-diphenylpropane-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxy Diphenyl-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate.

  A commercially available product may be used as the compound having two or more isocyanate groups in one molecule. Specifically, product names “Duranate TPA-100” manufactured by Asahi Kasei Chemicals Corporation, product names “Coronate L”, “Coronate HL”, “Coronate HK”, “Coronate HK” manufactured by Nippon Polyurethane Industry Co., Ltd. "Coronate 2096" etc. are mentioned.

  The amount of the compound having two or more isocyanate groups in one molecule can be set to any appropriate value. The amount is, for example, 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer having a urethane bond.

<A-2-3. Second catalyst>
Any appropriate amine-based catalyst is used as the second catalyst. By using an amine-based catalyst as the second catalyst, the urethane bond formation reaction can proceed smoothly as in the case where the organotin compound is used as the catalyst. Examples of the amine catalyst include triethylenediamine, tetramethylbutanediamine, 1,8-diazabicyclo [5,4,0] undencene-7, bis (2,2′-dimethylamino) ethyl ether, trimethylamine, triethylamine, N -Methylmorpholine, N-ethylmorpholine, N, N-dimethylbenzylamine, N, N'-dimethylethanolamine, N, N, N ', N'-tetramethyl-1,3-butanediamine, triethanolamine, Examples include hexamethylenetetramine and pyridine oxide. Only one type of catalyst may be used, or two or more types may be used in combination.

  The second catalyst is preferably a tertiary diamine, more preferably a tertiary diamine in which all groups bonded to two nitrogen atoms are alkyl groups. Tertiary diamines in which all the groups bonded to two nitrogen atoms are alkyl groups are more suitable because they have low steric hindrance around the unshared electron pair of amine, high nucleophilicity, and high reactivity. Can be used. Specific examples of the tertiary diamine in which all the groups bonded to two nitrogen atoms are alkyl groups include triethylenediamine.

  The usage-amount of a 2nd catalyst can be set to arbitrary appropriate values. For example, it is 0.001 part by weight to 1 part by weight with respect to 100 parts by weight of the (meth) acrylic polymer having the urethane bond. If the usage-amount of a 2nd catalyst is in said range, a 2nd reaction can be performed efficiently.

<A-2-4. Other ingredients>
The pressure-sensitive adhesive layer may further contain other components as long as the reaction promoting effect of the second catalyst is not impaired. Examples of the other components include crosslinkers other than isocyanate compounds, photopolymerization initiators, antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, and antistatic agents. The kind and usage-amount of another component can be suitably selected according to the objective.

<A-2-4-1. Photopolymerization initiator>
Any appropriate photopolymerization initiator can be used as the photopolymerization initiator. By further adding a photopolymerization initiator, it is possible to cure the pressure-sensitive adhesive layer more quickly by irradiating the obtained pressure-sensitive adhesive sheet with ultraviolet rays, and to provide a pressure-sensitive adhesive sheet with improved light peelability Can do.

  Any appropriate initiator can be used as the photopolymerization initiator. For example, benzoin alkyl ethers such as benzoin methyl ether, benzoisopropyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzyl, benzoin, benzophenone, aromatic ketones of α-hydroxycyclohexyl phenyl ketone; benzyldimethyl ketal, etc. And aromatic ketals such as polyvinylbenzophenone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone, and diethylthioxanthone. Only one type of photopolymerization initiator may be used, or two or more types may be used in combination.

  A commercial product may be used as the photopolymerization initiator. For example, trade names “Irgacure 651”, “Irgacure 184”, “Irgacure 369”, “Irgacure 819”, “Irgacure 2959” and the like manufactured by BASF may be mentioned.

  The usage-amount of a photoinitiator is 0.01 weight part-20 weight part with respect to 100 weight part of (meth) acrylic-type polymers which have a urethane bond, Preferably it is 0.1 weight part-10 weight part. Parts, more preferably 0.5 parts by weight to 10 parts by weight.

<A-2-5. Reaction method>
The second reaction is performed by any appropriate method. For example, the (meth) acrylic polymer having a urethane bond and a compound having two or more isocyanate groups in one molecule are reacted in the presence of the second catalyst and any other suitable components as necessary. Can be done.

  The reaction temperature of the second reaction can be set to any appropriate value. The said reaction temperature can be set to 40 to 65 degreeC, for example. The reaction temperature can be adjusted in any suitable heating means.

The reaction time of the second reaction is usually 48 hours to 96 hours. If the reaction time of the second reaction is within the above range, the hydroxyl group that can be contained in the (meth) acrylic polymer having a urethane bond and two or more in one molecule as in the case where the organotin compound is used as a catalyst. The cross-linking reaction with the isocyanate group of the compound having an isocyanate group can proceed smoothly. Therefore, an adhesive sheet can be manufactured without reducing manufacturing efficiency. The second reaction may be terminated when the presence or absence of an isocyanate group (specifically, the presence or absence of absorption at 2270 cm ⁻¹ ) is confirmed using FT-IR, and the isocyanate group is no longer confirmed.

  The second reaction may be performed continuously with the first reaction. That is, a compound having two or more isocyanate groups in one molecule, a second catalyst, and any appropriate other components as necessary are added to the reaction solution in which the first reaction is performed, and the second reaction is performed. You may go.

  The second reaction is a solution containing a (meth) acrylic polymer having a urethane bond, a second catalyst, and, if necessary, other additives from the viewpoint of production efficiency of the pressure-sensitive adhesive sheet (hereinafter referred to as pressure-sensitive adhesive layer). It is preferable to carry out the reaction by forming the pressure-sensitive adhesive layer on the base material layer of the pressure-sensitive adhesive sheet or the film subjected to the peeling treatment for transfer, and then heating.

  When the pressure-sensitive adhesive layer is formed on the base material layer or the transfer-released film, the second reaction can be performed, for example, by heating the pressure-sensitive adhesive sheet on which the pressure-sensitive adhesive layer is formed to a desired temperature. Examples of the heating means include an oven.

  The thickness of the pressure-sensitive adhesive layer when applied to the base material layer of the pressure-sensitive adhesive sheet or the film subjected to the release treatment for transfer can be set to any appropriate value. For example, the thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is 3 μm to 100 μm, preferably 5 μm to 65 μm.

  The base material layer is formed of any appropriate resin. Examples of the resin include polyolefins such as low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene, polybutene, and polymethylpentene. , Ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene Copolymer, polyurethane, polyester such as polyethylene terephthalate, polyimide, polyetherketone, polystyrene, polyvinyl chloride, polyvinylidene chloride, fluororesin, silicone resin, cellulosic resin, and cross-linking thereof And the like. In addition, you may use a commercially available polymer film as a base material layer.

  The base material layer may further contain other components as long as the effects of the present invention are not impaired. As said other component, the component similar to the other component which can be contained in the adhesive layer illustrated above can be used, for example.

  The thickness of the base material layer is preferably 30 μm to 185 μm, more preferably 55 μm to 175 μm.

  The base material layer can be formed by any appropriate method. Specifically, for example, a calendar method, a casting method, an inflation method, and a T-die extrusion method are preferably used. Moreover, you may use a commercially available plastic film as a base material layer.

  Any appropriate release film can be used as the release-treated film for transfer. For example, a plastic (for example, polyethylene terephthalate (PET), polyethylene, polypropylene) film, nonwoven fabric, or paper surface-coated with a release agent such as a silicon release agent, a fluorine release agent, or a long-chain alkyl acrylate release agent. It is done.

  A commercially available release film may be used as the release-treated film. As a commercially available peeling film, the brand name "Diafoil MRF38" by Mitsubishi Plastics, etc. are mentioned, for example.

  When forming the pressure-sensitive adhesive layer on the peel-treated film, after applying and drying the pressure-sensitive adhesive layer-forming material to the peel-treated film, the film to be the base material layer may be bonded to the formed pressure-sensitive adhesive layer. .

<A-3. Other processes>
The production method of the pressure-sensitive adhesive sheet of the present invention may include any other appropriate process other than the first reaction and the second reaction as necessary. For example, the process of forming arbitrary appropriate other layers in an adhesive sheet is mentioned. Examples of the other layers include a surface layer (heat resistant layer) that can impart heat resistance to the pressure-sensitive adhesive sheet, an antistatic layer, a back surface light release treatment layer, a friction reduction layer, and an easy adhesion treatment layer. These layers can be formed by any appropriate method.

  Usually, the pressure-sensitive adhesive sheet can be protected and provided by a separator that functions as a protective material that protects the pressure-sensitive adhesive sheet until it is practically used. Therefore, in one embodiment, the manufacturing method of the adhesive sheet of the present invention includes the process of laminating a separator. Separation of the separators can be performed by any appropriate method. As the separator, for example, a plastic (for example, polyethylene terephthalate (PET), polyethylene, polypropylene) film, a nonwoven fabric or a surface-coated with a release agent such as a silicon release agent, a fluorine release agent, and a long chain alkyl acrylate release agent For example, paper.

<B. Adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention is obtained by the method for producing the pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet of the present invention typically includes a base material layer and a pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet of the present invention may further include any appropriate other layer. Examples of other layers include a surface layer (heat-resistant layer) that can impart heat resistance to the pressure-sensitive adhesive sheet, an antistatic layer, a back surface light release treatment layer, a friction reduction layer, and an easy adhesion treatment layer.

  The pressure-sensitive adhesive sheet of the present invention can be provided while being protected by a separator. The pressure-sensitive adhesive sheet of the present invention can be rolled up in a state protected by a separator. Specific examples of the separator include those of the above item A.

  The thickness of the pressure-sensitive adhesive sheet can be set to any appropriate value. The thickness of the pressure-sensitive adhesive sheet is preferably 50 μm to 700 μm, more preferably 80 μm to 225 μm.

  The pressure-sensitive adhesive sheet of the present invention can be suitably used for semiconductor wafer processing. The pressure-sensitive adhesive sheet of the present invention is produced by a method that does not use an organotin compound as a catalyst. Therefore, even when the pressure-sensitive adhesive sheet is used and when the pressure-sensitive adhesive sheet after use is discarded, adverse effects on the human body and the environment due to the organotin compound can be prevented. Furthermore, in the method for producing a pressure-sensitive adhesive sheet of the present invention, a metal complex of zirconium, titanium, and aluminum is used as a catalyst for the first reaction. Conventionally, when a metal complex is used when preparing the polymer component contained in the pressure-sensitive adhesive composition, there is a problem of metal contamination of the semiconductor wafer due to the metal complex remaining in the pressure-sensitive adhesive layer. However, the metal complex used as the first catalyst has a low diffusion rate into the semiconductor wafer, and even when metal contamination occurs, the influence on the function of the semiconductor circuit is small. Therefore, the pressure-sensitive adhesive sheet of the present invention can be suitably used for semiconductor wafer processing applications. Furthermore, when the photopolymerization initiator is further included in the step of preparing the pressure-sensitive adhesive layer forming material, the pressure-sensitive adhesive layer is cured by irradiating the pressure-sensitive adhesive sheet, and light peelability can be exhibited. Therefore, the adhesive sheet can be easily peeled from the processed semiconductor wafer.

  When using the adhesive sheet of this invention for a semiconductor wafer processing use, it can be used as an adhesive sheet for back grinding processes, an adhesive sheet for dicing processes, etc., for example.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. Moreover, a part means a weight part.

[Example 1]
To a 1 L round bottom separable flask, separable cover, separatory funnel, thermometer, nitrogen inlet tube, Liebig condenser, vacuum seal, stirring rod and stirring blade to polymerization experimental apparatus to 2-ethyl acrylate 80 parts by weight of xyl (manufactured by Toa Gosei Co., Ltd.), 20 parts by weight of 2-hydroxyethyl acrylate (manufactured by Toa Gosei Co., Ltd.), 100 parts by weight of solvent (toluene), and benzoyl peroxide (Nippon Yushi Co., Ltd.) as a thermal polymerization initiator 0.2 parts by weight were manufactured. While stirring the charged mixture, nitrogen substitution was performed at room temperature for 1 hour. Next, while stirring under nitrogen flow, the solution temperature in the experimental apparatus was controlled to be 62 ° C. ± 2 ° C. with a water bath and maintained for 12 hours. In addition, toluene was added appropriately for temperature control during the polymerization process. Then, it cooled to normal temperature and obtained the (meth) acrylic-type polymer solution which has a 2 or more hydroxyl group in a side chain.
(First reaction)
To the obtained (meth) acrylic polymer solution, 20 parts by weight of 2-isocyanatoethyl methacrylate (made by Showa Denko KK, trade name “Karenz MOI”), zirconium tetraacetylacetonate (made by Matsumoto Fine Chemical Co., Ltd.) as the first catalyst , Trade name “Orgatechx ZC-150”) was added in an amount of 0.05 parts by weight, and the reaction temperature was controlled to 50 ° C. ± 2 ° C. while flowing in dry air. A sample of 1 cc was extracted from the reaction container every 2 hours, and the presence or absence of absorption at 2270 cm ⁻¹ was confirmed by FT-IR to confirm the presence or absence of isocyanate groups. The reaction time was 10 hours.
(Second reaction)
1 part by weight of a polyisocyanate-based crosslinking agent (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.) and 100% by weight of the (meth) acrylic polymer solution (solid content) having a urethane bond, the second catalyst As an adhesive layer forming material, 0.05 part by weight of triethylenediamine (trade name “TEDA” manufactured by Tosoh Corporation) and 3 parts by weight of a photopolymerization initiator (trade name “Irgacure 651” manufactured by BASF Corporation) are added. Obtained.
The obtained pressure-sensitive adhesive layer forming material is applied to a release-treated polyester film (trade name “Diafoil MRF38” manufactured by Mitsubishi Plastics) and dried at 120 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm. did. A polyester film (trade name “Lumirror S10 # 50” manufactured by Toray Industries, Inc.) was attached to the surface of the pressure-sensitive adhesive layer so as not to generate air bubbles to obtain a laminate. The obtained laminate was aged (second reaction) in an oven at 50 ° C. Every 12 hours, the presence or absence of an isocyanate group in the pressure-sensitive adhesive layer was confirmed by the presence or absence of absorption at 2270 cm ⁻¹ by FT-IR. The reaction was terminated when the isocyanate group disappeared to obtain an adhesive sheet. The reaction time for the second reaction was 48 hours.
Table 1 shows the catalyst used for the production and the reaction time.

[Example 2]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the amount of the first catalyst used was 0.1 parts by weight. In Example 2, the reaction time of the first reaction was 8 hours, and the reaction time of the second reaction was 48 hours. Table 1 shows the catalyst used for the production and the reaction time.

[Example 3]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the amount of the first catalyst used was 0.2 parts by weight. In Example 3, the reaction time of the first reaction was 6 hours, and the reaction time of the second reaction was 48 hours. Table 1 shows the catalyst used for the production and the reaction time.

[Example 4]
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 0.1 parts by weight of titanium tetraacetylacetonate (manufactured by Matsumoto Fine Chemical Co., Ltd., trade name “Orgatechs TC-401”) was used as the first catalyst. In Example 4, the reaction time of the first reaction was 12 hours, and the reaction time of the second reaction was 48 hours. Table 1 shows the catalyst used for the production and the reaction time.

[Example 5]
In the same manner as in Example 1, except that 0.1 parts by weight of aluminum monoacetylacetonate bis (ethylacetoacetate) (manufactured by Kawaken Chemical Co., Ltd., trade name “aluminum chelate D”) was used as the first catalyst. A sheet was obtained. In Example 5, the reaction time of the first reaction was 24 hours, and the reaction time of the second reaction was 48 hours. Table 1 shows the catalyst used for the production and the reaction time.

(Comparative Example 1)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that 0.05 part by weight of zirconium tetraacetylacetonate (manufactured by Matsumoto Fine Chemical Co., Ltd., trade name “Orgachix ZC-150”) was used as the second catalyst. In Comparative Example 1, the reaction time of the first reaction was 10 hours, and the reaction time of the second reaction was 288 hours. Table 1 shows the catalyst used for the production and the reaction time.

(Comparative Example 2)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 0.05 part by weight of triethylenediamine (trade name “TEDA”, manufactured by Tosoh Corporation) was used as the first catalyst. In Comparative Example 2, the reaction time of the first reaction was 72 hours, and the reaction time of the second reaction was 48 hours. Table 1 shows the catalyst used for the production and the reaction time.

(Reference example)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 0.05 part by weight of dibutyltin dilaurate (IV) (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the first catalyst and the second catalyst was not added. In Reference Example 1, the reaction time of the first reaction was 10 hours, and the reaction time of the second reaction was 48 hours. Table 1 shows the catalyst used for the production and the reaction time.

[Evaluation of adhesive strength]
The pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were cut into a width of 20 mm and a length of 150 mm to obtain test pieces. The test piece was attached to a silicon mirror wafer and allowed to stand at room temperature for 30 minutes, and then the adhesive strength was measured at a peeling angle of 90 degrees and a peeling speed of 300 mm / min. The adhesive strength of any adhesive sheet was 1.0 N / 20 mm, which was applicable as an adhesive sheet.
Similarly, each test piece was affixed to a silicon mirror wafer and allowed to stand at room temperature for 30 minutes, and then a UV irradiation device (made by Nitto Seiki Co., Ltd., trade name “ UM-810 ") was used for UV irradiation (illuminance: 60 mW / cm ² , light amount: 300 mJ / cm ² ), and then the adhesive strength was measured in the same manner. The pressure-sensitive adhesive strength of any pressure-sensitive adhesive sheet was 0.1 N / 20 mm and had light peelability.

  In Examples 1 to 5 using a complex of at least one metal selected from zirconium, titanium, and aluminum as the first catalyst and an amine compound as the second catalyst, the first reaction and the second reaction proceed smoothly. And an adhesive sheet could be obtained efficiently. Moreover, the time required for reaction was able to be adjusted by adjusting the usage-amount of a 1st catalyst (Examples 1-3). In Comparative Example 1 using a zirconium complex as the first catalyst and the second catalyst, the time until the end of the second reaction was lengthened, and the production efficiency was significantly reduced. Moreover, in the comparative example 2 using a triethylenediamine as a 1st catalyst and a 2nd catalyst, the reaction time of the 1st reaction became longer than Examples 1-5, and the manufacture efficiency of the adhesive sheet fell.

  The method for producing a pressure-sensitive adhesive sheet of the present invention can efficiently produce a pressure-sensitive adhesive sheet without using an organotin compound having a bad influence on the human body and the environment as a catalyst.

Claims (5)

(Meth) acrylic polymer having two or more hydroxyl groups in the side chain, and selected from the group consisting of (meth) acryloyl isocyanate, 2-isocyanatoethyl (meth) acrylate, m-isopropenyl-α, α-dimethylbenzyl isocyanate And reacting the compound having at least one isocyanate group in the presence of the first catalyst to form a (meth) acrylic polymer having a urethane bond, and
A pressure-sensitive adhesive sheet comprising a step of reacting the (meth) acrylic polymer having a urethane bond with a compound having two or more isocyanate groups in one molecule in the presence of a second catalyst to form a pressure-sensitive adhesive layer. A manufacturing method of
The first catalyst is a complex of at least one metal selected from zirconium, titanium, and aluminum;
The manufacturing method of the adhesive sheet whose said 2nd catalyst is an amine catalyst.   The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the first catalyst is a metal complex obtained by chelating at least one metal selected from zirconium, titanium, and aluminum with acetylacetone.   The manufacturing method of the adhesive sheet of Claim 1 or 2 whose said 2nd catalyst is tertiary diamine.   The method for producing a pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the compound having two or more isocyanate groups in one molecule is a compound having three or more isocyanate groups in one molecule. The manufacturing method of the adhesive sheet in any one of Claim 1 to 4 whose compound which has the said isocyanate group is 2-isocyanatoethyl (meth) acrylate.