JP5001532B2 - Cooling peelable pressure-sensitive adhesive composition, cooling peelable pressure sensitive adhesive sheet, and film processing method using the same - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as an adhesive sheet for temporarily fixing a workpiece in the processing of a film-like workpiece such as production of a flexible printed board, an optical film, a mask film, and various protective films. Regarding the cooling and peeling type pressure-sensitive adhesive sheet, in particular, when processing a film as an adherend, particularly when processing at a high temperature, it can be securely adhered to the adherend and can be easily peeled off at room temperature before and after processing. The present invention relates to a cooling peelable pressure-sensitive adhesive composition capable of exhibiting an appropriate degree of adhesive strength, a cooling peelable pressure sensitive adhesive sheet, and a film processing method using the cooling peelable pressure sensitive adhesive sheet.

  In recent years, the thickness of an insulating substrate of a flexible printed circuit board (FPC) has been reduced, and a reinforcing sheet is applied to the insulating substrate in various processes for processing the insulating substrate, such as a process of depositing metal on the insulating substrate, a step of plating, and a step of etching. It is indispensable to improve the handling property by sticking. In addition to the manufacture of FPC, in order to improve handling properties and prevent damage to the substrate when performing various processes such as sputtering, corona treatment, plasma treatment, matte treatment by sanding on the film-like substrate, A reinforcement sheet is pasted on the material.

  Since such a reinforcing sheet needs to be peeled after processing is completed, a re-peelable pressure-sensitive adhesive sheet is usually used as the reinforcing sheet. As such a releasable pressure-sensitive adhesive sheet, for example, a UV-curing that has a pressure-sensitive adhesive layer containing a UV-curable oligomer and reduces the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer by using the curing of the oligomer by UV irradiation. A mold pressure-sensitive adhesive sheet has been proposed (see, for example, Patent Document 1).

  In addition, it has a pressure-sensitive adhesive layer containing heat-expandable microspheres, and makes use of the expansion of the heat-expandable microspheres by heating, and hence the reduction in the contact area between the adherend and the pressure-sensitive adhesive layer. A heat-peelable pressure-sensitive adhesive sheet that reduces the force has been proposed (see, for example, Patent Documents 2 to 5).

Furthermore, it has an adhesive layer containing an adhesive polymer whose main chain and / or side chain is a crystalline polymer, and reduces the adhesive force of the adhesive layer by utilizing crystallization of the crystalline polymer by cooling. A cooling peelable adhesive sheet has also been proposed (see, for example, Patent Documents 6 and 7).
JP-A-9-291258 JP-A-11-302614 JP 2000-351947 A JP 2002-69422 A JP 2003-160765 A JP-A-9-251923 JP 2003-138237 A

  All of these removable pressure-sensitive adhesive sheets have sufficient adhesive strength when used, but can reduce the adhesive strength after use and can be peeled off without leaving the adhesive on the adherend. It is supposed to be possible.

  However, the ultraviolet curable adhesive sheet and the heat-peelable adhesive sheet are irreversibly reduced in adhesive force, and are designed to have a large adhesive force at room temperature in consideration of the film processing temperature range. For this reason, when the film thickness of the adherend is thin, the re-sticking operation is particularly difficult, and forcibly removing it may destroy the adherend or adversely affect the intended film characteristics. In addition, when UV irradiation or heat treatment is performed for re-sticking, the pressure-sensitive adhesive sheet that can be peeled off can no longer be used.

  On the other hand, a pressure-sensitive adhesive that can be re-removed at room temperature usually has a tendency to reduce the adhesive strength at high temperatures, and therefore cannot provide sufficient adhesion at the film processing temperature. Therefore, there is no pressure-sensitive adhesive sheet that meets the requirements for re-peelability at room temperature and high adhesive strength at high temperatures, so re-releasable holding film during processing near room temperature and when processing at high temperatures is required A non-reusable releasable holding film, for example, an irreversible releasable sheet such as an ultraviolet curable pressure sensitive adhesive sheet or a heat peelable pressure sensitive adhesive sheet, was used in each step. Such UV curable pressure sensitive adhesive sheets and heat-peelable pressure sensitive adhesive sheets require UV irradiation or high-temperature heating when reducing the adhesive strength, and UV or heat is applied not only to the pressure sensitive adhesive layer but also to the adherend or pressure sensitive adhesive sheet. It will also act on the material. Therefore, there is a risk of adverse effects on the adherend and the like.

  In addition, after the ultraviolet curable adhesive sheet is used at a high temperature, the heat-peelable adhesive sheet has unevenness in the expansion of the thermally expandable microsphere. When re-bonding occurs, there are cases where the decrease in adhesive strength is not sufficient, and there is a problem in terms of peelability after use. If the peelability after use is inferior, the adherend may be damaged at the time of peeling, or the adhesive layer remains on the adherend until it does not break (often referred to as “glue residue”), and the firing step This is not preferable in that it causes blocking, voids, cracks, and the like, leading to a decrease in reliability and yield of the final product.

  On the other hand, unlike the ultraviolet curable pressure sensitive adhesive sheet and the heat peelable pressure sensitive adhesive sheet, the cooling peelable pressure sensitive adhesive sheet described in Patent Documents 6 and 7 does not require ultraviolet irradiation or high temperature heating when reducing the adhesive force. . Therefore, ultraviolet rays and heat do not adversely affect the workpiece and the like, and there is an advantage that it can be reused even after the adherence is peeled off once the adhesive force is reduced. .

  However, since the cooling peelable pressure-sensitive adhesive sheet described in Patent Document 6 or 7 has a small initial peel force, it is difficult to hold the adherend at room temperature, and adhesive residue or the like tends to occur. Such a problem becomes a particularly serious problem when processing a very thin film.

  As described above, at present, there is little adverse effect on the adherend due to ultraviolet rays or heat, and it can be reused even after the adherend has been peeled off once the adhesive force has been reduced. When the film as the adherend is processed, particularly when processed at high temperatures, the adherend can be securely adhered to the adherend. A cooling peelable pressure-sensitive adhesive sheet capable of exhibiting an appropriate adhesive strength to such an extent that it can be easily peeled has not been disclosed yet, and the creation of such a cooling peelable pressure sensitive adhesive sheet has been eagerly desired by the industry.

  The present invention has been made to address the problems of the prior art as described above, and has little adverse effect on the adherend due to ultraviolet rays or heat, and after the adherend has been peeled off once the adhesive force has been reduced. In addition to being reusable, it can be securely attached to the adherend during film processing and has a certain level of holding power before and after processing, but is easy when holding is no longer necessary. The present invention provides a cooling peelable pressure-sensitive adhesive composition, a cooling peelable pressure-sensitive adhesive sheet, and a film processing method using the same.

  According to the present invention, the following cooling peelable pressure-sensitive adhesive composition, cooling peelable pressure sensitive adhesive sheet, and a film processing method using the same are provided.

[1] It is formed from a raw material composition containing A to C components, the mass ratio of the A component to the B component is 99.5: 0.5 to 50:50, and the amount of the C component is the above It is 0.3-4.0 mass parts with respect to 100 mass parts in total of A component and the said B component, The said A component is (meth) acrylic acid by which the C1-C4 alkyl group was ester-bonded. It is a temperature-sensitive adhesive polymer obtained by polymerizing a monomer component containing 50% by mass or more of an ester, and the B component has 6 to 8 carbon atoms having a polarity lower than that of the alkyl group having 1 to 4 carbon atoms. It is a low-polarity adhesive polymer obtained by polymerizing a monomer component containing 40% by mass or more of an (meth) acrylic ester ester-bonded with an alkyl group, and the C component is an isocyanate-based crosslinking agent, and Adhesive strength in the adhesive strength test is 40- A cooling peelable pressure-sensitive adhesive composition that exhibits a maximum value in a temperature range of 100 ° C., and the maximum value is 0.4 N / cm or more.
Adhesion test:
After cooling the peelable pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer made of a cold-peelable adhesive having a thickness of 7 μm is disposed on the surface of a PET film having a thickness of 50 μm, to 10 mm wide and 250 mm long and heated to 60 ° C. Then, an aramid film having a thickness of 4.2 μm is attached to the adhesive layer, and a rubber roller is reciprocated once under the conditions of a pressing force of 2 kg and a speed of 300 mm / min to obtain a test piece. After leaving this test piece at a predetermined temperature and humidity of 65% RH for 20 minutes, the aramid film was pulled from the test piece in the 180 ° direction at a tensile speed of 300 mm / min with the tensile tester at the predetermined temperature and humidity. The peeling force at the time of peeling is measured, and this peeling force is defined as the adhesive strength at the predetermined temperature.

[2] The cooling peelable pressure-sensitive adhesive composition according to the above [1], wherein the adhesive strength at 23 ° C. is 0.005 to 0.1 N / cm.

[ 3 ] The cooling peelable pressure-sensitive adhesive composition according to [ 1 ] or [2] , wherein the temperature-sensitive adhesive polymer has a glass transition temperature (Tg) of −10 to 50 ° C.

[ 4 ] A cooling peelable pressure-sensitive adhesive sheet comprising a film-like substrate and an adhesive layer on one surface of the substrate, wherein the adhesive layer is cooled according to any one of the above [1] to [ 3 ]. A cooling peelable pressure-sensitive adhesive sheet comprising a peelable pressure-sensitive adhesive composition.

[ 5 ] A step of processing a laminated body in which the cooling peelable pressure-sensitive adhesive sheet according to [ 4 ] above is attached to a film-like workpiece, and a step of peeling the cooling peelable pressure sensitive adhesive sheet from the laminate. Including film processing method.

  The cooling peelable pressure-sensitive adhesive composition and the cooling peelable pressure-sensitive adhesive sheet of the present invention are capable of reliably adhering to an adherend during the processing of a film, and have an appropriate adhesive strength that allows easy peeling before and after processing. Can show.

  Hereinafter, the best mode for carrying out the cooling peelable pressure-sensitive adhesive composition of the present invention, the coolable peelable pressure sensitive adhesive sheet, and the film processing method using the same will be specifically described. The form is not limited.

[1] Cooling Peelable Adhesive Composition FIG. 1 is a schematic diagram showing the temperature dependence of the adhesive strength in the following adhesive strength test of the cooled peelable adhesive composition of the present invention.

Adhesion test:
A cooling peelable pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer made of a 7 μm-thick cooling peelable pressure-sensitive adhesive is disposed on the surface of a 50 μm-thick PET (polyethylene terephthalate) film is cut into a width of 10 mm and a length of 250 mm, and then heated to 60 ° C. After raising the temperature, an aramid film having a thickness of 4.2 μm is attached to the adhesive layer, and a rubber roller is reciprocated once under the conditions of a pressing force of 2 kg and a speed of 300 mm / min to obtain a test piece. After leaving this test piece at a predetermined temperature and humidity of 65% RH for 20 minutes, the aramid film was pulled from the test piece in the 180 ° direction at a tensile speed of 300 mm / min with the tensile tester at the predetermined temperature and humidity. The peeling force at the time of peeling is measured, and this peeling force is defined as the adhesive strength at the predetermined temperature.

  As shown in FIG. 1, the cooling peelable pressure-sensitive adhesive composition of the present invention exhibits a maximum in the temperature range of 40 to 100 ° C., and this maximum value is the maximum value A. The maximum value A is 0.4 N / cm or more, preferably 0.5 N / cm or more, and more preferably 0.6 N / cm or more. Further, the adhesive force B at 23 ° C. is preferably 0.005 to 0.3 N / cm, more preferably 0.005 to 0.1 N / cm, and 0.005 to 0.08 N / cm. It is particularly preferred that

  The cooling peelable pressure-sensitive adhesive composition of the present invention is not particularly limited as long as it has the above properties, but is formed from a raw material composition containing the following temperature-sensitive pressure-sensitive adhesive polymer as a main component. A suitable example is a cooling peelable pressure-sensitive adhesive composition.

(1) Temperature-sensitive adhesive polymer (component A)
The temperature-sensitive adhesive polymer in the present invention is an adhesive polymer having a property that the adhesive force changes depending on a temperature change, and an alkyl group having 1 to 4 carbon atoms is ester-bonded (meth) It is an adhesive polymer obtained by polymerizing a monomer component mainly composed of an acrylate ester.

  In this specification, “(meth) acrylic acid” means acrylic acid or methacrylic acid, and “(meth) acrylic acid ester” means acrylic acid ester or methacrylic acid ester. The (meth) acrylic acid ester in which an alkyl group having 1 to 4 carbon atoms is ester-bonded is an alkyl ester of (meth) acrylic acid, and the (meth) acrylic having 1 to 4 carbon atoms in the alkyl group. It is an acid ester (hereinafter, a (meth) acrylic acid ester in which an alkyl group having 1 to 4 carbon atoms is ester-bonded is referred to as a component (a1)).

  The temperature-sensitive adhesive polymer is preferably an adhesive polymer having a glass transition temperature in the temperature range of −10 to 50 ° C., preferably 0 to 30 ° C. By having the glass transition temperature in such a temperature range, the above-described temperature-dependent characteristics of adhesive force can be easily expressed. That is, when the temperature rises above the glass transition temperature in the above range, the adhesive polymer softens and exhibits high adhesive strength, while the adhesive polymer cures and adheres in the temperature range near and below the glass transition temperature. As a result of the decrease, the temperature-dependent characteristics of the adhesive force as described above can be easily expressed. That is, by setting the glass transition temperature to −10 ° C. or higher, preferably 0 ° C. or higher, it is possible to moderately reduce the adhesive strength at room temperature, and by setting the glass transition temperature to 50 ° C. or lower, 40 to 100 Adhesive strength in the temperature range of ° C. can be improved.

  The temperature-sensitive adhesive polymer can be obtained by polymerizing a monomer component having the component (a1) as a main component, but one or more (a1) components are used to arbitrarily add another monomer component (a2). By polymerizing with the components, the glass transition temperature of the temperature-sensitive adhesive polymer can be set to the above temperature range.

  As the alkyl group having 1 to 4 carbon atoms in the component (a1), 1-propyl group (n-propyl group), 1-methylethyl group (iso-propyl group), 1-butyl group (n-butyl group), Examples include 2-methylpropyl group (iso-butyl group), 1-methylpropyl group (sec-butyl group), 1,1-dimethylethyl group (tert-butyl group) and the like. Therefore, as the component (a1), methyl methacrylate, ethyl ester, 1-propyl ester (n-propyl ester), 1-methyl ethyl ester (iso-propyl ester), 1-butyl ester (n -Butyl ester), 2-methylpropyl ester (iso-butyl ester), 1-methylpropyl ester (sec-butyl ester), 1,1-dimethylethyl ester (tert-butyl ester) and the like.

  Examples of the component (a2) include acrylonitrile, acrylamide, (meth) acrylic acid, acrylic monomers such as (meth) acrylic acid esters other than the component (a1), styrene, vinyl acetate, N-vinylpyrrolidone, and the like. . Moreover, the monomer which has a functional group (henceforth "reactive functional group") which can react with a crosslinking agent as (a2) component is also preferable.

  As the reactive functional group, a carboxyl group, a hydroxyl group, an amino group, or the like is known, but the adhesive strength at room temperature can be lowered, and it can be characterized by excellent removability after processing. A hydroxyl group is preferred. Examples of the acrylic monomer having a hydroxyl group as a reactive functional group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, and 4-hydroxybutyl acrylate. , 4-hydroxybutyl methacrylate and the like.

  The proportion of the component (a1) in the monomer component is 50% by mass or more, preferably 55% by mass or more, and more preferably 70% by mass or more. The proportion of the component (a2) in the monomer component is 50% by mass or less, preferably 45% by mass or less, and more preferably 30% by mass or less.

  The temperature-sensitive adhesive polymer preferably has a weight average molecular weight (sometimes abbreviated as “Mw”) of 200,000 or more, more preferably in the range of 200,000 to 1,000,000. It is particularly preferable that it is in the range of 10,000 to 500,000. When the weight average molecular weight is less than the above range, it is not preferable in that the adhesive force may be lowered in a temperature range of 40 to 100 ° C., and when it exceeds the above range, it is preferable in that removability tends to be insufficient. Absent.

  The weight average molecular weight (Mw) is determined by appropriately controlling the type and amount of the chain transfer agent, the molar ratio of the monomer to the polymerization initiator, and the like when polymerizing the “temperature-sensitive adhesive polymer”. Adjustment can be made within the above range. Moreover, you may select suitably and use what has a desired weight average molecular weight from commercially available adhesive polymers.

  The temperature-sensitive adhesive polymer can be obtained, for example, by a method of radical polymerization of the aforementioned component (a1) and optional component (a2). The polymerization method is not particularly limited, and a conventionally known polymerization method such as an emulsion polymerization method, a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or a photopolymerization method can be suitably used.

(2) Low polarity adhesive polymer (component B)
The raw material composition forming the cooling peelable pressure-sensitive adhesive composition of the present invention preferably contains a low-polarity adhesive polymer in addition to the above-mentioned temperature-sensitive adhesive polymer. Low-polar adhesive polymer means (meth) acrylic acid ester ((b1) component) in which an alkyl group having a lower polarity than the alkyl group (C1-C4 alkyl group) of component (a1) is ester-bonded An adhesive polymer obtained by polymerizing a monomer component containing As the component (b1), a (meth) acrylic ester in which an alkyl group having 6 to 8 carbon atoms is ester-bonded is preferable. When the raw material composition contains such a low-polarity adhesive polymer, it becomes easy to show moderate slight adhesiveness at room temperature.

  Examples of the alkyl group having 6 to 8 carbon atoms include 1-hexyl group (n-hexyl group), 1-heptyl group (n-heptyl group), 1-octyl group (n-octyl group), 6-methylheptyl. Group (iso-octyl group), 2-ethylhexyl group and the like. Accordingly, acrylic acid or methacrylic acid ester monomers having an ester bond with an alkyl group having 6 to 8 carbon atoms include 1-hexyl ester (n-hexyl ester) and 1-heptyl ester (n-heptyl ester) of acrylic acid or methacrylic acid. Ester), 1-octyl ester (n-octyl ester), 6-methylheptyl ester (iso-octyl ester), 2-ethylhexyl ester and the like. Among them, it is preferable to use 2-ethylhexyl ester which is inexpensive and easily available. The component (b1) is preferably contained in an amount of 40% by mass or more, preferably 50 to 98% by mass with respect to all monomers forming the component B in order to ensure the effect.

  The monomer component forming the B component may contain another monomer component (component (b2)) in addition to the component (b1) described above. Examples of the optional component (b2) include the same components as the component (a2) described above. A monomer having a reactive functional group is also preferred as the component (b2). Examples of the reactive functional group and the monomer having a reactive functional group include the same ones as mentioned in the component (a2). The ratio of the component (b2) to the total monomer components forming the component B is 0 to 60% by mass, preferably 2 to 50% by mass. Moreover, the ratio with respect to all the monomer components which form B component of the monomer which has a reactive functional group is 0-50 mass%, Preferably it is 1-40 mass%. In addition, since it is preferable that B component has a glass transition temperature in the temperature range of -30--80 degreeC, it is preferable to select the combination of a monomer so that a glass transition point may exist in this temperature range.

  The weight average molecular weight (Mw) of the low polarity adhesive polymer is preferably 100,000 to 700,000, and more preferably 100,000 to 600,000. When the weight average molecular weight (Mw) is less than 100,000, it is not preferable because the low-polar adhesive polymer easily migrates to the adherend, and when it is 700,000 or more, it is possible to effectively prevent adhesive residue. This is not preferable in that it cannot be performed.

  In addition, a weight average molecular weight (Mw) can be adjusted in said range by the method similar to a temperature-sensitive adhesive polymer. The low-polarity adhesive polymer can be produced in the same manner as the production method (polymerization method) described in the section of the temperature-sensitive adhesive polymer.

(3) Crosslinking agent (component C)
The “crosslinking agent” in the present invention means a substance that can form a crosslinked polymer by crosslinking the temperature-sensitive adhesive polymer or the low-polarity adhesive polymer described above. When the polymer and / or the low-polar adhesive polymer has a reactive functional group, it reacts with these to form a crosslinked polymer. By forming the crosslinked polymer, it becomes easy to exhibit sufficient adhesive force during film processing and excellent peelability after cooling.

  Generally, as the crosslinking agent, an isocyanate crosslinking agent, a metal chelate crosslinking agent, an epoxy crosslinking agent, or the like is known. In the present invention, an isocyanate crosslinking agent can be preferably used.

  As an isocyanate type crosslinking agent, a conventionally well-known isocyanate type crosslinking agent, for example, a polyvalent isocyanate compound, its oligomer, a prepolymer, etc. can be used conveniently. Examples of the polyvalent isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane. Examples include -2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and lysine isocyanate. Among them, hexamethylene diisocyanate trimer (for example, trade name: Takenate D-170N, manufactured by Mitsui Takeda Chemical Co., Ltd.) can be preferably used. This cross-linking agent is preferable in that it has the effect of imparting excellent removability and heat resistance. In addition, a "crosslinking agent" may be used independently and may be used in combination of 2 or more type.

  As described above, the preferred cooling-peelable pressure-sensitive adhesive composition of the present invention can be formed from a raw material composition containing the component A as a main component and the components B and C. The mass ratio of component A: component B is preferably in the range of 99.5: 0.5 to 50:50, more preferably in the range of 90:10 to 60:40. The amount of component C is preferably 0.3 to 4.0 parts by mass, and more preferably 0.3 to 1.5 parts by mass with respect to 100 parts by mass of the total of component A and component B. By crosslinking such a raw material composition, it is possible to easily develop the adhesive property as shown in FIG.

  In addition, the cooling release pressure-sensitive adhesive formed from the raw material composition containing the A component, the B component, and the C component in the above-described proportions is a low molecular weight material when used under conditions close to vacuum such as sputtering. It also has the feature that it does not easily migrate to the surface. Furthermore, it has the feature that it can be used without curing.

[2] Cooling-peelable pressure-sensitive adhesive sheet The cooling-peelable pressure-sensitive adhesive sheet of the present invention includes a film-like substrate, and an adhesive layer containing the above-described cooling-peelable pressure-sensitive adhesive composition is provided on at least one surface thereof. It is.

  There are no particular restrictions on the constituent material of the base material that constitutes the cooling peelable pressure-sensitive adhesive sheet, and it is appropriately selected from the materials conventionally used as the base material for pressure-sensitive adhesive sheets according to the use of the cooling peelable pressure-sensitive adhesive sheet can do. Specifically, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polycarbonate, triacetyl cellulose, cellophane, polyimide, polyamide, polyphenylene sulfide, polyetherimide, polyethersulfone, aromatic polyamide, or polysulfone, or other synthetic resin, It can be selected from glass, metal, ceramic and the like. The base material may be transparent or colored. Coloring can be performed by a method of blending various pigments or dyes into the constituent material of the substrate. The surface of the substrate is not limited to a smooth surface, and the surface may be processed into a mat shape.

Even if a base material contains the conventionally well-known additive in the constituent material, specifically, a heat stabilizer, an oxidation stabilizer, a weather stabilizer, a ultraviolet absorber, an antistatic agent, etc. Good. Moreover, it is preferable to use what gave surface treatment for the purpose of improving adhesiveness with an adhesion layer. Examples of the surface treatment include discharge treatment such as corona discharge treatment and glow discharge treatment, plasma treatment, flame treatment, ozone treatment, ionizing active ray treatment such as ultraviolet treatment, electron beam treatment and radiation treatment, sand mat treatment and anchor treatment, Examples thereof include surface roughening treatment such as hairline treatment, chemical treatment, and easy adhesion layer coating treatment. The thickness of the substrate may be appropriately selected according to the field of application of the cooling peelable pressure-sensitive adhesive sheet, but is usually 12 to 250 μm, and preferably 25 to 125 μm from the viewpoint of followability to the adherend and transportability. .

  The thickness of the adhesive layer is not particularly limited, but is preferably 2 to 100 μm, more preferably 2 to 50 μm, and particularly preferably 2 to 20 μm. When the thickness of the pressure-sensitive adhesive layer is less than the above range, it is not preferable in that sufficient adhesive force to the adherend may not be obtained.

  The adhesive layer is prepared by, for example, dissolving or dispersing the above-described raw material composition in an appropriate solvent to form an adhesive layer forming coating solution having a solid content concentration of about 10 to 50% by mass. Can be obtained by a method in which at least one surface of a substrate is coated according to a conventional method and dried.

At this time, the adhesive layer-forming coating solution includes various conventionally used additives such as a crosslinking accelerator, an antioxidant, a stabilizer, a viscosity modifier, a tackifier resin, or an organic or inorganic filler. May be added. Examples of the crosslinking accelerator include triethylamine-based, cobalt naphthenate-based, and tin-based crosslinking accelerators, and in particular, stannous chloride, tetra-n-butyltin, trimethyltin hydroxide, dimethyltin chloride, dilaurate. It is preferable to use a tin-based crosslinking accelerator such as -n-butyltin. In addition, as an antioxidant, a phenolic antioxidant, etc., as a tackifier resin, a terpene resin, etc., as an organic filler, an acrylic or urethane spherical fine particle, etc., as an inorganic filler Silica, calcium carbonate, alumina and the like can be preferably used.

  There are no particular restrictions on the method of application, and a conventionally known application using a Mayer bar, applicator, brush, spray, roller, gravure coater, die coater, lip coater, comma coater, knife coater, reverse coater, spin coater, etc. The method can be used. The surface of the substrate to which the adhesive layer-forming coating solution is applied or the film having releasability (hereinafter referred to as “substrate etc.”) may be subjected to surface treatment in advance as necessary. .

  There is no restriction | limiting in particular also about a drying method, Conventionally well-known drying methods, such as hot air drying and reduced pressure drying, can be utilized. About drying conditions, what is necessary is just to set suitably according to the kind of adhesive, the kind of solvent used by coating liquid, the film thickness of an adhesion layer, etc., but it is common to dry at the temperature of about 60-180 ° C. Is. In the case where the raw material composition has a crosslinkable composition, the raw material composition can be crosslinked by this heating.

  Depending on the amount of volatile matter remaining in the adhesive layer (hereinafter referred to as “residual volatile matter amount”), the adhesiveness between the adhesive layer and the substrate or the peelability after cooling may be adversely affected. Accordingly, the residual volatile content in the adhesive layer is preferably 4% by mass or less, and more preferably 2% by mass or less. In addition, what is necessary is just to adjust the quantity of the solvent for preparing the adhesion layer formation coating liquid, the drying time after coating, etc. in order to set it as the desired residual volatile matter amount.

[3] Film Processing Method The film processing method of the present invention is a method in which a releasable pressure-sensitive adhesive sheet is attached to a film-like workpiece to form a laminate, and the laminate is processed, and then the releasable pressure-sensitive adhesive sheet. It is the processing method of the film provided with the process of peeling and obtaining a processed body, and uses the cooling peeling type adhesive sheet of this invention as a releasable adhesive sheet.

  The film processing method of the present invention is characterized in that the cooling-peelable pressure-sensitive adhesive sheet of the present invention is used as the re-peelable pressure-sensitive adhesive sheet, and the other points are the same as the conventional method. Although there is no restriction | limiting in particular in the film which is a to-be-processed body, An aramid film, a polyimide film, PET film, a liquid crystal polymer film etc. are mentioned. Although there is no restriction | limiting also in the thickness of a film, Usually, it is 2-100 micrometers. Moreover, the cooling peeling type adhesive sheet of this invention can be applied especially suitably for thin film processing, and it is preferable from this viewpoint that the thickness of a film is 2-50 micrometers. Examples of film processing include plating, sputtering, vapor deposition, plasma treatment, matting treatment by sanding, exposure, development, and etching. In particular, the cooling peelable pressure-sensitive adhesive sheet of the present invention can be used in many processing steps in the FPC manufacturing process, and a number of processing steps can be performed using a single cooling peelable pressure sensitive adhesive sheet. Further, in the plating step, it is possible to effectively suppress the penetration of the plating solution between the adherend and the adhesive sheet. Moreover, in the affirmation using a roll, such as a sputtering process, generation | occurrence | production of the wrinkle at the time of winding up by a roll can be suppressed effectively.

  Hereinafter, the cooling peelable pressure-sensitive adhesive composition of the present invention and the cooling peelable pressure sensitive adhesive sheet will be specifically described with reference to examples, but the cooling peelable pressure sensitive adhesive composition of the present invention and the cooling peelable pressure sensitive adhesive sheet are It is not limited at all by these examples.

[Temperature dependence of adhesive strength]
After production, the pressure-sensitive adhesive sheets of Examples and Comparative Examples, which were not subjected to heat treatment or ultraviolet irradiation treatment, were cut to a width of 10 mm and a length of 250 mm and heated to 60 ° C., and then the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was thickened. A 4.2 μm aramid film (trade name: Aramika, manufactured by Teijin Advanced Film Co., Ltd.) was attached, and a rubber roller was reciprocated once under the conditions of a pressing force of 2 kg and a speed of 300 mm / min to obtain a test piece. After leaving this test piece for 20 minutes under the following test temperature and 65% RH, the aramid film was peeled off from the test piece in the direction of 180 ° at a tensile speed of 300 mm / min under the temperature and humidity conditions. The peel force was measured and the peel force was defined as the adhesive strength at this test temperature.
Test temperature: 23 ° C, 40 ° C, 60 ° C, 80 ° C, 100 ° C

[Adhesive strength after heating]
After preparing a test piece and allowing it to stand for 20 minutes, the test piece is heated in a circulating oven at 100 ° C. for 2 hours, and then cooled under conditions of a temperature of 23 ° C. and a humidity of 65% RH. The peel strength was measured in the same manner as in the temperature dependence test of the adhesive strength, except that the peel strength was measured in the above, and the post-heating adhesive strength was obtained.

[Adhesive strength after hot pressing]
After applying the aramid film, it was pressure-bonded by heating and pressurizing at 150 ° C. and 2.4 kg / cm ² for 60 minutes, and the test piece was heated at 23 ° C. and humidity 65% RH for 20 minutes. After leaving, the peel strength was measured in the same manner as in the temperature dependence test of the adhesive strength except that the peel strength was measured under the temperature and humidity conditions, and the adhesive strength was determined after hot pressing.

[Characteristic evaluation]
After production, the pressure-sensitive adhesive sheets of Examples and Comparative Examples, which were not subjected to heat treatment or ultraviolet irradiation treatment, were cut to a width of 10 mm and a length of 250 mm and heated to 60-80 ° C. The adherend 1 or the adherend 2 was affixed and pressure-bonded by reciprocating a rubber roller having a mass of 2 kg to obtain a test piece. The test piece was allowed to stand at room temperature for 20 minutes and then evaluated 1 or 2 below.
Substrate 1: Aramid film with a thickness of 4.2 μm (trade name: Aramika, manufactured by Teijin Advanced Films)
Adherent 2: PET film with a thickness of 25 μm

Evaluation 1:
The surface on the adherend side of the test piece to which the adherend 1 is attached is subjected to Ni / Cr sputtering treatment in a vacuum, and then copper plating is performed on the sputtered surface by electrolytic plating at 50 ° C., followed by 90 Gold plating was performed by electroless plating at ° C. After this test piece was cooled under the conditions of 23 ° C. and humidity 65% RH, the adherend 1 was peeled from the test piece by hand. There is no deviation or peeling between the adherend 1 and the pressure-sensitive adhesive sheet during the sputtering process, and there is no penetration of the plating solution between the adherend 1 and the pressure-sensitive adhesive sheet during the plating process. When the body 1 can be peeled off, “◯” indicates that there is no deviation or peeling between the adherend 1 and the adhesive sheet during the sputtering process, and plating is performed between the adherend 1 and the adhesive sheet during the plating process. Although there is no liquid intrusion, it is “△” when it is difficult to peel off the adherend 1 after cooling, and when the adherend 1 and the adhesive sheet are displaced or peeled off during the sputtering process, At that time, the case where there was an infiltration of the plating solution between the adherend 1 and the adhesive sheet and the case where the adherend 1 could not be peeled after cooling were evaluated as “x”.

Evaluation 2:
The surface on the adherend side of the test piece to which the adherend 2 was attached was subjected to aluminum sputtering treatment in a vacuum. After this test piece was cooled under the conditions of 23 ° C. and humidity 65% RH, the adherend 1 was peeled from the test piece by hand. In the sputtering process, there is no deviation or peeling between the adherend 2 and the pressure-sensitive adhesive sheet, and “○” indicates that the adherend 2 can be easily peeled off after cooling. When there is no deviation or peeling from the pressure-sensitive adhesive sheet, but it is difficult to peel the adherend 2 after cooling, or when adhesion of components derived from the pressure-sensitive adhesive sheet is observed on the surface of the adherend 2, "△", sputtering treatment In this case, the case where there was a deviation or peeling between the adherend 1 and the pressure-sensitive adhesive sheet or the case where the adherend 2 could not be peeled after cooling was evaluated as “x”.

Evaluation 3:
Adhering the pressure-sensitive adhesive sheet having a length of 50 m and a width of 600 mm and the adherend 1 having the same length and width as the pressure-sensitive adhesive sheet with a roll-to-roll under the following lamination conditions so that the adherend is inside. Winding up and preparing a test specimen. The test specimen was unwound under an environment of a temperature of 23 ° C. and a humidity of 65% RH at a tension of 4 kgf and a conveyance speed of 5 m / min, and the state of the adherend and the adhesive sheet when taken up with a take-up roll was visually observed. Observed. The case where peeling between the adherend and the pressure-sensitive adhesive sheet was not observed was evaluated as “◯”, and the case where peeling between the adherend and the pressure-sensitive adhesive sheet was observed was evaluated as “x”.
Lamination conditions:
Laminate roll temperature 160 ° C,
Pasting pressure 2kg / cm ² ,
Pasting speed 5m / min

  In the examples and comparative examples, the following polymers (component A and component B) and crosslinking agent (component C) were used.

(A-1 component)
It is an acrylic resin having a weight average molecular weight of 240,000 and a glass transition temperature of 15 ° C. It is a polymer obtained by polymerizing monomer components of 20% by mass of methyl methacrylate, 70% by mass of ethyl acrylate, and 10% by mass of acrylonitrile. That is, it is a polymer containing 90% by mass of a structural unit derived from a (meth) acrylic acid ester in which an alkyl group having 1 to 4 carbon atoms is ester-bonded.

(A-2 component)
It is an acrylic resin having a weight average molecular weight of 370,000 and a glass transition temperature of 11 ° C. It is a polymer obtained by polymerizing monomer components of 15% by mass of methyl methacrylate, 70% by mass of ethyl acrylate, and 15% by mass of acrylonitrile. That is, it is a polymer containing 85% by mass of a structural unit derived from a (meth) acrylic acid ester in which an alkyl group having 1 to 4 carbon atoms is ester-bonded.

(A-3 component)
It is an acrylic resin having a weight average molecular weight of 360,000 and a glass transition temperature of 24 ° C. It is a polymer obtained by polymerizing monomer components of 15% by mass of methyl methacrylate, 60% by mass of ethyl acrylate, and 25% by mass of acrylonitrile. That is, it is a polymer containing 75% by mass of a structural unit derived from a (meth) acrylic acid ester in which an alkyl group having 1 to 4 carbon atoms is ester-bonded.

(A-4 component)
It is an acrylic resin having a weight average molecular weight of 700,000 and a glass transition temperature of 15 ° C. Highly obtained by polymerizing monomer components of 43.7% by mass of ethyl acrylate, 25% by mass of methyl acrylate, 20% by mass of methyl methacrylate, 1.3% by mass of 2-hydroxyethyl methacrylate and 10% by mass of acrylonitrile. Is a molecule. That is, a high component containing 88.7% by mass of a structural unit derived from a (meth) acrylic ester ester-bonded with an alkyl group having 1 to 4 carbon atoms and 1.3% by mass of a structural unit derived from a reactive functional group-containing monomer. Is a molecule.

(A-5 component)
It is an acrylic resin having a weight average molecular weight of 360,000 and a glass transition temperature of 20 ° C. It is a polymer obtained by polymerizing 98.7% by mass of butyl methacrylate and 1.3% by mass of 2-hydroxyethyl methacrylate. That is, a high component containing 98.7% by mass of a structural unit derived from a (meth) acrylic ester ester-bonded with an alkyl group having 1 to 4 carbon atoms and 1.3% by mass of a structural unit derived from a reactive functional group-containing monomer. Is a molecule.

(B-1 component)
It is an acrylic resin having a weight average molecular weight of 390,000 and a glass transition temperature of −42 ° C. It is a polymer obtained by polymerizing monomer components of 65% by mass of 2-ethylhexyl acrylate, 2% by mass of 2-hydroxyethyl methacrylate and 33% by mass of vinyl acetate.

(B-2 component)
It is an acrylic resin having a weight average molecular weight of 550,000 and a glass transition temperature of −49 ° C. It is a polymer obtained by polymerizing a monomer component of 94% by mass of butyl acrylate and 6% by mass of acrylic acid.

(B-3 component)
It is an acrylic resin having a weight average molecular weight of 550,000 and a glass transition temperature of −49 ° C. It is a polymer obtained by polymerizing 97% by mass of 2-ethylhexyl acrylate and 3% by mass of 2-hydroxyethyl methacrylate.

(C-1 component)
It is an isocyanate-based crosslinking agent, and its constituent component is a trimer of hexamethylene diisocyanate (trade name: Takenate D-170N, manufactured by Mitsui Takeda Chemical Co., Ltd.).

(C-2 component)
It is an epoxy-based crosslinking agent, and its constituent component is 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane.

Example 1
85 parts by weight of component A-2 as a temperature-sensitive adhesive polymer, 15 parts by weight of component B-1 as a low-polarity adhesive polymer, 0.6 parts by weight of component C-1 as a crosslinking agent, and 1 methylethylketone and toluene 300 parts by mass of a mixed solvent mixed at a mass ratio of 1 was added and stirred and mixed to prepare an adhesive layer forming coating solution.

  Next, this coating solution was applied to the surface of a PET film having a thickness of 50 μm as a base material with a baker type applicator so that the film thickness after drying was 7 μm, and this was further applied at 80 ° C. for 1 minute. An adhesive layer was formed by heating and drying at 130 ° C. for 3 minutes. A stretched polypropylene (OPP: Oriented Polypropylene, trade name: Alphan, Oji Paper Co., Ltd.) film having a thickness of 30 μm was stuck on the surface of the adhesive layer as a release liner to obtain an adhesive sheet.

(Example 2)
Except for using 80 parts by mass of the A-1 component as the temperature-sensitive adhesive polymer, 20 parts by mass of the B-1 component as the low-polarity adhesive polymer, and 1.5 parts by mass of the C-1 component as the crosslinking agent. In the same manner as in Example 1, a pressure-sensitive adhesive sheet was obtained.

(Example 3)
40 parts by mass of A-1 component and 40 parts by mass of A-2 component as a temperature-sensitive adhesive polymer, 20 parts by mass of B-1 component as a low polarity adhesive polymer, 0.8 mass of C-1 component as a crosslinking agent The adhesive sheet was obtained like Example 1 except having used the part.

(Comparative Example 1)
The same procedure as in Example 1 was conducted except that 30 parts by mass of the B-2 component, 70 parts by mass of the B-3 component, and 9 parts by mass of the C-2 component were used without using the temperature-sensitive adhesive polymer (component A). An adhesive sheet was obtained.

(Comparative Example 2)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 20 parts by mass of the A-1 component, 80 parts by mass of the B-1 component, and 0.6 parts by mass of the C-1 component were used.

(Comparative Example 3)
A pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that 100 parts by mass of the A-1 component and 0.8 parts by mass of the C-1 component were used without using the low-polarity adhesive polymer (component B).

  These formulations and evaluation results are shown in Table 1.

  As is clear from the results in Table 1, the cooling peelable adhesive sheets of Examples 1 to 3 showed the maximum value of the adhesive force in the temperature range of 40 to 100 ° C., and the maximum value was 0.4 N / cm. As described above, in any processing of the adherend 1 and the adherend 2, there is no occurrence of peeling or misalignment or infiltration of plating after bonding, and it is easy to remove from the adherend when cooling and peeling. It can be seen that it can be peeled off.

  The cooling peelable pressure-sensitive adhesive composition and the cooling peelable pressure-sensitive adhesive sheet of the present invention can be reliably peeled off when the film is securely fixed to a film as an adherend and when it is desired to peel from the adherend. Therefore, it can be suitably used for processing various films.

It is a figure which shows typically the temperature dependence of the adhesive force of the cooling peeling adhesive composition of this invention.

Claims (5)

Formed from a raw material composition containing A to C components,
The mass ratio of the component A: component B is 99.5: 0.5-50: 50, and
The amount of the C component is 0.3 to 4.0 parts by mass with respect to a total of 100 parts by mass of the A component and the B component,
The component A is a temperature-sensitive adhesive polymer obtained by polymerizing a monomer component containing 50% by mass or more of a (meth) acrylic ester ester-bonded with an alkyl group having 1 to 4 carbon atoms,
The B component is obtained by polymerizing a monomer component containing 40% by mass or more of a (meth) acrylic ester ester-bonded with an alkyl group having 6 to 8 carbon atoms having a polarity lower than that of the alkyl group having 1 to 4 carbon atoms. Low polar adhesive polymer obtained,
The component C is an isocyanate crosslinking agent,
A cooling peelable pressure-sensitive adhesive composition having a maximum value in a temperature range of 40 to 100 ° C. and having a maximum value of 0.4 N / cm or more.
Adhesion test:
After cooling the peelable pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer made of a cold-peelable adhesive having a thickness of 7 μm is disposed on the surface of a PET film having a thickness of 50 μm, to 10 mm wide and 250 mm long and heated to 60 ° C. Then, an aramid film having a thickness of 4.2 μm is attached to the adhesive layer, and a rubber roller is reciprocated once under the conditions of a pressing force of 2 kg and a speed of 300 mm / min to obtain a test piece. After leaving this test piece at a predetermined temperature and humidity of 65% RH for 20 minutes, the aramid film was pulled from the test piece in the 180 ° direction at a tensile speed of 300 mm / min with the tensile tester at the predetermined temperature and humidity. The peeling force at the time of peeling is measured, and this peeling force is defined as the adhesive strength at the predetermined temperature.   The cooling peelable pressure-sensitive adhesive composition according to claim 1, wherein the adhesive strength at 23 ° C is 0.005 to 0.1 N / cm. The cooling peelable pressure-sensitive adhesive composition according to claim 1 or 2 , wherein the temperature-sensitive adhesive polymer has a glass transition temperature (Tg) of -10 to 50 ° C. A cooling peelable pressure-sensitive adhesive sheet according to any one of claims 1 to 3 , wherein the pressure sensitive adhesive sheet is provided with a film-like base material and an adhesive layer on one surface of the base material. A cooling peelable pressure-sensitive adhesive sheet comprising the composition. A method for processing a film, comprising: a step of processing a laminate in which the cooling release adhesive sheet according to claim 4 is attached to a film-like workpiece; and a step of peeling the cooling release adhesive sheet from the laminate. .

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