TW201437320A - Double-faced pressure-sensitive adhesive sheet - Google Patents

Abstract

A double-faced pressure-sensitive adhesive sheet of the present invention includes a pressure sensitive adhesive layer having a first surface and a second surface, a first release film allowed to adhere to the first surface, and a second release film allowed to adhere to the second surface. A peel force of the second release film from the pressure sensitive adhesive layer is weaker than a peel force of the first release film from the pressure sensitive adhesive layer. An arithmetic average roughness Ra of an opposite surface with respect to a surface of each of the first release film and the second release film making contact with the pressure sensitive adhesive layer is 5 to 35 nm. A roughness Rp of maximum profile peak height of the opposite surface is 50 to 400 nm. It is possible for such a double-faced pressure-sensitive adhesive sheet to prevent minute irregularities from generating on the surfaces of the pressure sensitive adhesive layer when it is wound in a roll shape and stored.

Description

Double-sided adhesive sheet

The present invention relates to a double-sided adhesive sheet.

An optical functional film system such as a polarizing plate is fixed to a member such as a liquid crystal cell by using a double-sided adhesive sheet made of an adhesive. Here, such a double-sided adhesive sheet is produced, for example, by applying an adhesive on the first release film to form an adhesive layer, and then attaching a second release film to the formed adhesive layer. Moreover, the double-sided adhesive sheet thus manufactured is generally wound into a roll shape for storage or handling.

In recent years, in order to improve productivity, the winding length of a double-sided adhesive sheet wound into such a roll shape has gradually increased. Further, in the application as an optical functional film body, it is recognized that a low elastic modulus adhesive having a light leakage resistance and a printing error traceability is present in a large amount, and the adhesive is easily affected by external stress. As a result, when stored in a state of being wound into a roll, there is a problem that a large number of minute irregularities (orange peels) occur on the surface of the adhesive layer on the core portion of the roll.

Further, in the prior art, the polarizing plate with the adhesive is attached to the liquid crystal cell and then subjected to autoclave treatment. However, in recent years, the process is simplified and the autoclave treatment is not performed. Therefore, if the adhesive layer has orange peel, it will There is a possibility of increasing the incorporation of fine bubbles and causing a low yield. Further, if orange peel is formed in the adhesive layer, the appearance is poor when assembled in the display, resulting in a low yield.

For this reason, it has been attempted to prevent such an orange peel by making the surface roughness Ra of the release-shaped surface of the release film 100 nm or less (see, for example, Patent Document 1, Japanese Patent Laid-Open Publication No. 2010-185038).

However, as the length of the drum winding has increased in recent years, the conventional double-sided adhesive sheet has been unable to sufficiently prevent the problem of orange peel. Moreover, when one of the release films is peeled off from the adhesive layer, one of the adhesive layers partially adheres to the one of the release films, and the adhesive layer does not remain in the other of the good state in a smooth appearance. The problem of the phenomenon on the film, that is, the problem of the sticky phenomenon called crying separation.

An object of the present invention is to provide a double-sided adhesive sheet which can prevent a plurality of minute irregularities (orange peel) from occurring on the surface of the adhesive layer when being wound into a roll shape, and can prevent the separation from being called crying separation. Turn to stickiness.

The object is achieved by the present invention of (1) to (5) below.

(1) A double-sided adhesive sheet comprising an adhesive layer, a first release film, and a second release film. The adhesive layer has a first surface and a second surface. The first release film is attached to the aforementioned first surface of the aforementioned adhesive layer. A second release film is attached to the aforementioned second surface of the adhesive layer. The release force of the second release film peeled off from the adhesive layer is smaller than the first release film from the adhesive layer Stripped off the force. The surface of the first release film and the second release film opposite to the surface in contact with the adhesive layer has an arithmetic mean roughness Ra of 5 to 35 nm and a maximum protrusion height Rp of 50 to 400 nm.

(2) The double-sided adhesive sheet according to the above (1), wherein a ratio of the unevenness outside the range of ±0.2 μm from the reference surface to the first surface of the adhesive layer is 20% or less.

(3) The double-sided adhesive sheet according to the above (1) or (2), wherein the ratio of the unevenness outside the range of ±0.2 μm from the reference surface to the second surface of the adhesive layer is 20 %the following.

(4) The double-sided adhesive sheet according to any one of (1) to (3), wherein the adhesive constituting the adhesive layer is (meth)acrylic acid ester copolymerization Things.

(5) The double-sided adhesive sheet according to any one of (1) to (4) above, wherein the release force of the first release film peeled off from the adhesive layer is expressed as X [mN/25 mm] When the release force of the second release film peeled off from the adhesive layer is expressed as Y [mN / 25 mm], the relationship of XY ≧ 5 is satisfied.

According to the present invention, it is possible to provide a double-sided adhesive sheet which can be used, for example, to attach an optical functional film body such as a polarizing plate, and to prevent a plurality of minute on the surface of the adhesive layer when it is wound into a roll shape for storage. In the case of unevenness, it can prevent the phenomenon of turning into a sticky phenomenon called crying separation. Moreover, it is possible to provide a double-sided adhesive sheet which can, for example, suppress blocking and suppress static electricity when the release film is taken out from the drum.

1‧‧‧Double-sided adhesive sheet

10‧‧‧Adhesive layer

101‧‧‧ first surface

102‧‧‧ second surface

11‧‧‧First release film

111‧‧‧First release agent layer

112‧‧‧First substrate film

12‧‧‧Second release film

121‧‧‧Second release agent layer

122‧‧‧Second substrate film

Fig. 1 is a side sectional view showing the double-sided adhesive sheet of the present invention.

The invention will be described in detail below with reference to preferred embodiments.

The double-sided adhesive sheet will be described below.

The double-sided adhesive sheet of the present invention is used, for example, to bond an optical functional film such as a polarizing plate to a member such as a liquid crystal cell.

Fig. 1 is a side sectional view showing the double-sided adhesive sheet of the present invention.

As shown in FIG. 1, the double-sided adhesive sheet 1 includes an adhesive layer 10 having a first surface 101 and a second surface 102, and a first release member disposed on the first surface 101 of the adhesive layer 10. The film 11 and one of the second release films 12 disposed on the second surface 102 of the adhesive layer 10. For the adhesive layer 10, after the first release film 11 and the second release film 12 are removed, there is no support.

The double-sided adhesive sheet of the present invention is a double-sided adhesive sheet 1 having an adhesive layer 10, a first release film 11 and a second release film 12 as described above, and has the following features. That is, the feature that the release force of the second release film 12 peeled off from the adhesive layer 10 is smaller than the release force of the first release film 11 from the adhesive layer 10, and The surface of the release film 11 and the second release film 12 opposite to the surface in contact with the adhesive layer 10 has an arithmetic mean roughness Ra of 5 to 35 nm and a maximum protrusion height Rp of 50 to 400 nm. .

By having such a feature, the double-sided adhesive sheet 1 is wound into a roll When the tubular shape is stored or transported, it is possible to prevent the occurrence of minute irregularities (orange peel) on the first surface 101 and the second surface 102 of the adhesive layer 10.

Furthermore, the release force by the second release film 12 peeling off from the adhesive layer 10 is smaller than the release force of the first release film peeled off from the adhesive layer 10, and the second release film 12 can be prevented from occurring. When peeling off from the adhesive layer 10, one part of the adhesive layer 10 is adhered to the second release film 12, and the adhesive layer does not remain on the first release film in a smooth appearance, that is, it is called For the crying separation of the sticky phenomenon.

Further, in the present specification, the release force peeled off from the adhesive layer 10 is a release force measured as follows.

The measurement of the release force was carried out according to Japanese Industrial Standards JIS-Z0237, and the double-sided adhesive sheet 1 was cut into a width of 25 mm and a length of 200 mm, and the state of the adhesive layer 10 was fixed using a tensile tester. Next, the film was stretched in a direction of 180 degrees at a speed of 300 mm per minute.

Hereinafter, each layer constituting the double-sided adhesive sheet 1 of the present embodiment will be described in detail.

The adhesive layer 10 will be described below.

The adhesive layer 10 has a first surface 101 and a second surface 102.

The adhesive agent such as an acryl-based adhesive, a polyester-based adhesive, or a urethane-based adhesive can be used as the adhesive constituting the adhesive layer 10, but To use propylene-based adhesives It is better. The type of the adhesive may be of a solvent type or an emulsion type.

Among the propylene-based adhesives, a (meth)acrylic acid ester copolymer is preferably used. The acrylate copolymer has high transparency and can be suitably used for optical parts. Moreover, the acrylate copolymer is excellent in durability.

When the adhesive is a propylene-based adhesive, it can be composed of a polymer or a copolymer, and the polymer or copolymer mainly consists of a monomer component imparting adhesiveness, a polymer component imparting adhesion and cohesive force, and It is made of a monomer component containing a crosslinking point or a functional group for improving adhesion.

The main monomer component is, for example, methyl acrylate, ethyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate. ), carbon atoms of an alkyl group of an octyl acrylate, cyclohexyl acrylate, benzyl acrylate, and methoxyethyl acrylate A number of 1 to 20 alkyl acrylates, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, A material such as an alkyl group having an alkyl group having an ester moiety such as benzyl methacrylate and having 1 to 20 carbon atoms. The comonomer component is, for example, methyl acrylate, methyl methacrylate, ethyl methacrylate, Materials such as vinyl acetate, styrene, and acrylonitrile.

Further, the monomer component containing a functional group is preferably at least one of a hydroxyl group, a carboxyl group and an amino group as a functional group, and a specific example is (meth)acrylic acid. 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate (3-hydroxypropyl() Meth)acrylate), 2-hydroxybutyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, and (meth)acrylic acid (meth)acrylic acid hydroxy alkyl ester such as 4-hydroxybutyl (meth)acrylate; monomethylaminoethyl (meth) acrylate (monomethylaminoethyl (meth) Meth)acrylate), monoethylaminoethyl(meth)acrylate,monomethylaminopropyl(meth)acrylate, and (meth)acrylic acid monoethyl Monoalkylaminoalkyl (meth) acrylate, etc.; monoalkylaminoalkyl (meth)acrylate; Acid, methacrylic acid, crotonic acid (2-butenoic acid), maleic acid (maleic acid), itaconic acid (methylene succinic acid) and citrine A material such as ethylenic unsaturation carboxylic acid such as citraconic acid (methyl maleic acid). By containing these various components, the adhesion of the adhesive layer 10 can be improved cohesion.

Further, the (meth) acrylate-based copolymer is not particularly limited in its copolymerization form, and may be any random, block or graft copolymer.

Further, the (meth) acrylate-based copolymer is preferably a mass average molecular weight of 500,000 or more, preferably 600,000 to 2,000,000, and more preferably 700,000 to 1,800,000. Thereby, the double-sided adhesive sheet 1 and the adherend can have sufficient adhesion and adhesion durability, and the occurrence of floating, peeling, and the like can be more effectively prevented. Here, the mass average molecular weight is a value measured by a gel permeation chromatography (GPC) method and converted to a value converted by polystyrene.

In addition, in the (meth) acrylate-based copolymer, the content of the unit derived from the monomer component containing a functional group is preferably in the range of 0.01 to 10% by mass. When the content is 0.01% by mass or more, the crosslinking is sufficiently carried out by a reaction with a crosslinking agent to be described later, and the durability is good. The preferred content of the unit derived from the monomer component containing a functional group is from 0.05 to 7.0% by mass, and more preferably from 0.2 to 6.0% by mass.

Among them, one type or a combination of two or more types of materials may be used as the (meth) acrylate type copolymer (A).

Furthermore, such propylene-based adhesives are generally capable of improving the stability to light and oxygen due to the absence of unsaturated bonds in the molecule. Moreover, by appropriately selecting the type and molecular weight of the monomer, it is possible to obtain a product according to the use. Adhesives of quality and properties.

The adhesive layer 10 can be applied to the first release film 11 or the second release film 12 by preparing an adhesive solution (adhesive composition) in which such an adhesive is dissolved in an organic solvent. form.

Although any of the cross-linking type to which the cross-linking treatment is applied and the non-cross-linking type to which the cross-linking treatment is not applied can be used for such an adhesive composition, it is preferred to use a cross-linking type. In the case of using a crosslinked type, an adhesive layer having a better cohesive force can be formed. As a crosslinking agent using a crosslinked adhesive composition, it may be an isocyanate compound, an epoxy compound, a metal chelate compound, an alkoxide, a metal salt or an amine. (amine) a compound, a hydrazine compound, and an aldehyde compound.

The organic solvent used to prepare the adhesive composition may be, for example, toluene, xylene, methanol, ethanol, isobutanol, n-butanol (n-butanol). ), acetone (acetone), methyl ethyl ketone (MEK), tetrahydrofuran and ethyl acetate.

The concentration of the adhesive composition is adjusted to a range of a solid content of 5 to 60% by mass using such an organic solvent for coating convenience. The application of the adhesive composition to the first release film 11 or the second release film 12 can be performed, for example, by a bar coat method, a reverse roll coat method, or a knife coat method. , roll knife coat method, gravure coat method, air doctor coat method and doctor blade coat The method and the like are carried out in a conventionally known coating method.

The average thickness of the adhesive layer 10 is preferably 3 to 30 μm, more preferably 5 to 28 μm. Thereby, it can be suitably used for the thickness of a thin display.

On the first surface 101 of the adhesive layer 10, the proportion of the unevenness outside the range of ±0.2 μm from the reference surface is preferably 20% or less. Thereby, when the double-sided adhesive sheet 1 is attached to the adherend, it is possible to more effectively prevent the occurrence of appearance defects.

On the second surface 102 of the adhesive layer 10, the ratio of the unevenness outside the range of ±0.2 μm from the reference surface is preferably 20% or less. Thereby, when the double-sided adhesive sheet 1 is attached to the adherend, it is possible to more effectively prevent the occurrence of appearance defects.

The first release film will be described below.

The first release film 11 is attached to the first surface 101 of the adhesive layer 10.

This first release film 11 has a function of protecting the adhesive layer 10.

As shown in Fig. 1, the first release film 11 is formed by stacking the first release agent layer 111 and the first base material film 112 from the surface position in contact with the adhesive layer 10 to form a stacked body.

The first base film 112 has a function of imparting physical strength such as rigidity and flexibility to the first release film 11 .

The material constituting the first base film 112 may be various synthetic resins, for example, a polybutylene terephthalate (PBT) resin or a polyethylene terephthalate (PET) resin. And polyester resin such as polyethylene naphthalate (PEN) resin is preferred to use polyethylene terephthalate An ester resin is preferred. The first base film 112 may be a single layer film, or may be a multilayer film of two or more layers composed of the same or different materials. Such a multilayer film can be formed by laminating an adhesive layer interposed between the film bodies formed in advance, or by caking the resin layer on the film formed in advance. Formed by the composition. In order to form a resin layer forming composition of the resin layer, a compound such as an epoxy compound, an acrylate compound, an urethane acrylate compound, or a polyester compound may be used as a main component, and A crosslinking agent, a catalyst, a photopolymerization initiator, and a UV absorber are included as needed. The resin layer-forming composition may have curability, and may be, for example, any of curability such as thermosetting property, photocurability, or electron beam curability. Therefore, the multilayer film body in which the resin layer is formed by coating the resin layer forming composition on the film body formed in advance, the arithmetic mean roughness Ra and the maximum protrusion height of the outer surface of the first base film 112 can be adjusted. Rp.

In addition, the first base film 112 may also contain a filler. The filler may be, for example, a material such as silica, titania, calcium carbonate, kaolin, and alumina.

Although the thickness of the first base film 112 is not particularly limited, it is preferably 10 to 300 μm, and more preferably 15 to 200 μm.

Further, although the arithmetic mean roughness Ra of the surface of the first release film 11 opposite to the surface in contact with the adhesive layer 10 is 5 to 35 nm, it is preferably 13 to 30 nm. Thereby, the first surface 101 of the adhesive layer 10 can be more effectively prevented by the passage of time after the double-sided adhesive sheet 1 is wound into a roll shape. And the second surface 102 has an orange peel phenomenon. On the other hand, if the arithmetic mean roughness Ra does not reach the aforementioned lower limit value, the first release film 11 will agglomerate after the first release film 11 is wound into a roll shape, and it will not be prevented. The first release film 11 generates static electricity when it is taken out from the drum. On the other hand, when the arithmetic mean roughness Ra exceeds the upper limit value, the first surface 101 and the first layer 101 of the adhesive layer 10 cannot be prevented from passing through after the double-sided adhesive sheet 1 is wound into a roll shape. The surface of the second surface 102 is orange peel.

Further, the surface of the first release film 11 opposite to the surface in contact with the adhesive layer 10 has a maximum protrusion height Rp of 50 to 400 nm, preferably 90 to 240 nm. Thereby, after the double-sided adhesive sheet 1 is wound into a roll shape, the orange peel phenomenon can be effectively prevented from occurring on the first surface 101 and the second surface 102 of the adhesive layer 10 over time.

The first release agent layer 111 has a function of imparting a release property to the first release film 11.

The first release agent layer 111 is formed by applying a first release agent layer-forming composition containing a first release agent to the surface of the first base film 112 and drying it.

The first release agent is not particularly limited and may be an alkyd compound, a propylene oxime compound, a silicone compound, a long-chain alkyl group-containing compound, or a fluorine. Materials such as compounds. Among these materials, an alkyd-based compound, an acryl-based compound, an anthrone-based compound, and a compound having a long-chain alkyl group are preferably used as the first release agent.

As the alkyd compound, an alkyd compound having a crosslinked structure is usually used. For example, the formation of the alkyd compound layer having a crosslinked structure can be a method of heating and hardening a layer formed of an alkyd compound, a crosslinking agent, and a thermosetting composition containing a curing catalyst as required. . Further, the alkyd compound may be a denatured product such as a long-chain alkyl-modified alkyd compound or an anthrone-modified alkyd compound.

As the propylene oxime compound, a propylene oxime compound having a crosslinked structure is usually used. Among them, the propylene oxime compound may be a denatured product such as a long-chain olefin-modified acryl oxime compound and an fluorenone-modified acryl oxime compound.

The anthrone-based compound may be an anthrone-based compound containing polydimethyl siloxane as a basic skeleton. The anthrone-based compound has an addition reaction type, a condensation reaction type, an ultraviolet curing type, and an electron beam curing type. Compared with the condensation reaction type anthrone type compound, the addition reaction type anthrone type compound has high reactivity and can optimize productivity, and has the advantages of little change in the release force after production and no hardening and shrinkage.

Specifically, the above-described addition reaction type fluorenone compound may be an organopolysiloxane having two or more such as a vinyl group or an allyl group at a molecular terminal and/or a side chain. Alkenyl having 2 to 10 carbon atoms, such as (allyl), propenyl or hexenyl. When such an addition reaction type anthrone compound is used, it is preferred to use a crosslinking agent and a catalyst in combination.

The above crosslinking agent is, for example, having one molecule and at least two hydrazines An organic polyoxane of an atom-bonded hydrogen atom, specifically, for example, a dimethyl hydrogen siloxy-terminated dimethyl siloxane-methylhydroquinone (methyl hydrogen siloxane) copolymer, trimethyl siloxy-terminated dimethyl methoxy oxane-methylhydroquinoxane copolymer, trimethyl siloxy-terminated A material such as methyl hydrogen polysiloxane or poly (hydrogen silsesquioxane).

Further, the catalyst may be particulate platinum, particulate platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefinic complex of chloroplatinic acid, palladium, ruthenium. A platinum-based metal compound such as (rhodium). By using such a catalyst, the hardening reaction of the composition for forming a release agent layer can be performed more efficiently.

The long-chain alkyl group-containing compound is, for example, a polyvinylamino group obtained by reacting a long-chain alkyl isocyanate having a carbon number of 8 to 30 in a polyvinyl alcohol-based polymer. A polyvinyl carbamate, and an alkylurea derivative obtained by, for example, using a long-chain alkyl isocyanate having a carbon number of 8 to 30 in polyethyleneimine (PEI).

As the fluoride, a compound such as a fluorine silicone compound or a boron compound can be used.

In the composition for forming the first release agent layer, an additive may be appropriately mixed. The additives may be materials such as catalysts, dyes, and dispersants.

In the first release agent layer 111, the material of the first release agent layer forming composition is appropriately selected in such a manner that the release force of the first release film 11 is greater than the release force of the second release film 12. .

In the case where an anthrone compound is used as the first release agent, it is preferred to add an MQ resin in an appropriate amount as a heavy release controlling agent.

The first release agent composition may also suitably contain a dispersant or a solvent for the viscosity at the time of coating to fall within an appropriate range.

The dispersant or solvent is aromatic hydrocarbons such as toluene, fatty acid esters such as ethyl acetate, and methyl ethyl ketone (MEK). It is preferably an organic solvent such as a ketone or an aliphatic hydrocarbon such as hexane or heptane.

In the first release agent composition, the content of the first release agent is not particularly limited, but is preferably from 0.3 to 10% by mass.

Among them, the coating method can be, for example, a gravure coat method, a bar coat method, a spray coat method, a spin coat method, an air knife coat method, and a roll. A method such as a roll coat method, a blade coat method, a gate roll coat method, a die coat method, or the like, wherein a gravure coating method and a bar coating method are preferred, and a bar coating method is preferred. The law is especially good.

Further, the drying temperature is not particularly limited, preferably 100 to 150 degrees Celsius, and the drying time is preferably 10 seconds to 1 minute.

The thickness of the first release agent layer is preferably 0.01~5μm, and 0.03~ 3μm is especially good.

The arithmetic mean roughness Ra of the surface of the first release film 11 that is in contact with the adhesive layer 10 (the outer surface of the first release agent layer 111) is preferably 5 to 50 nm, and the maximum protrusion height Rp is 50 to 1000 nm. Preferably, the arithmetic mean roughness Ra of the surface in contact with the adhesive layer 10 is preferably from 13 to 50 nm, and the maximum protrusion height Rp is preferably from 120 to 1000 nm. Thereby, when the adhesive layer 10 is formed on the first release film 11, the surface shape of the first surface 101 of the adhesive layer 10 can be kept good. Further, even when the first release film 11 is stored at a relatively high temperature, no agglomeration occurs, and it is possible to effectively prevent the core portion of the first release film 11 from being lifted due to an increase in the release force. Bad situation.

Further, on the outer surface of the first release agent layer 111, the proportion of the unevenness outside the range of ±0.2 μm from the reference surface is preferably 20% or less. Thereby, when the adhesive layer 10 is formed on the first release film 11, the surface shape of the first surface 101 of the adhesive layer 10 can be kept good.

The second release film will be described below.

The second release film 12 is attached to the second surface 102 of the adhesive layer 10.

This second release film 12 has a function of protecting the adhesive layer 10.

As shown in Fig. 1, the second release film 12 is formed by stacking the second release agent layer 121 and the second base film 122 in this order from the surface contact with the adhesive layer 10.

As the second base film 122, the same material as that of the first base film 112 described in the item of the first release film 11 described above can be used.

Further, the surface of the second release film 12 opposite to the surface in contact with the adhesive layer 10 has an arithmetic mean roughness Ra of 5 to 35 nm, preferably 12 to 30 nm. Thereby, when the double-sided adhesive sheet 1 is wound into a roll shape, it is possible to more effectively prevent the orange peel phenomenon from occurring on the first surface 101 and the second surface 102 of the adhesive layer 10. On the other hand, if the arithmetic mean roughness Ra does not reach the aforementioned lower limit value, the second release film 12 will agglomerate after the second release film 12 is wound into a roll shape, and the second release film 12 will be agglomerated and cannot be prevented. The second release film 12 generates static electricity when it is taken out from the drum. On the other hand, when the arithmetic mean roughness Ra exceeds the upper limit value, the first surface 101 and the first layer 101 of the adhesive layer 10 cannot be prevented from passing through after the double-sided adhesive sheet 1 is wound into a roll shape. The surface of the second surface 102 is orange peel.

Further, the maximum protrusion height Rp of the surface of the second release film 12 opposite to the surface in contact with the adhesive layer 10 is preferably 50 to 400 nm, more preferably 120 to 240 nm. Thereby, after the double-sided adhesive sheet 1 is wound into a roll shape, the orange peel phenomenon can be effectively prevented from occurring on the first surface 101 and the second surface 102 of the adhesive layer 10 over time.

The second release agent layer 121 is formed by applying a second release agent layer-forming composition containing a second release agent to the surface of the second base film 122 and drying it.

The second release agent can be appropriately selected from the materials constituting the first release agent described in the item of the first release film described above.

In the second release agent layer 121, the second release film 12 is separated from the shape The material of the second release agent layer-forming composition is appropriately selected in such a manner that the force is smaller than the release force of the first release film 11.

The second release agent layer 121 may have only one layer, or may have two or more layers, and it is preferable to use one layer for simplifying the operation.

The thickness of the second release agent layer 121 is preferably 0.01 to 5 μm, more preferably 0.03 to 3 μm.

The arithmetic mean roughness Ra of the surface of the second release film 12 that is in contact with the adhesive layer 10 (the outer surface of the second release agent layer 121) is preferably 5 to 50 nm, and the maximum protrusion height Rp is 50 to 1000 nm. Preferably, the arithmetic mean roughness Ra of the surface in contact with the adhesive layer 10 is preferably from 13 to 50 nm, and the maximum protrusion height Rp is preferably from 120 to 1000 nm. Thereby, when the second release film 12 is attached to the second surface 102 of the adhesive layer 10 to form the double-sided adhesive sheet 1, the surface shape of the second surface 102 of the adhesive layer 10 can be kept good. Further, even if the second release film 12 is stored at a relatively high temperature, the agglomeration does not occur, and the core portion of the second release film 12 can be effectively prevented from being released due to the increase in the release force. Bad situation.

Further, on the outer surface of the second release agent layer 121, the proportion of the unevenness outside the range of ±0.2 μm from the reference surface is preferably 20% or less. Thereby, when the second release film 12 is attached to the second surface 102 of the adhesive layer 10 to form the double-sided adhesive sheet 1, the surface shape of the second surface 102 of the adhesive layer 10 can be kept good.

When the release force of the first release film 11 peeled off from the adhesive layer 10 is expressed as X [mN / 25 mm], and the second release film 12 is peeled off from the adhesive layer 10 When the pull-out force is expressed as Y [mN/25 mm], it is preferable to satisfy the relationship of X-Y≧5, and it is preferable to satisfy the relationship of 60≧X-Y≧10. Thereby, it is possible to more effectively prevent the phenomenon that one part of the adhesive layer adheres to the second release film when the second release film is peeled off from the adhesive layer, that is, the transfer phenomenon called crying separation.

The present invention has been described in detail above based on preferred embodiments, but the present invention is not limited thereto.

The embodiment will be described below.

Next, a specific embodiment of the double-sided adhesive sheet relating to the present invention will be explained.

The production of the double-sided adhesive sheet will be described below.

Embodiment 1 will be explained below.

The production of the first release film will be described below.

A polyethylene terephthalate (PET) film (thickness: 38 μm, arithmetic mean roughness Ra: 20 nm, maximum protrusion height Rp: 203 nm) having the same roughness on the back surface was prepared as the first substrate film.

Next, the first release agent layer-forming composition A having the following composition was applied to one of the surfaces of the first substrate film by a bar coater in a thickness of 0.1 μm after drying to Celsius The first release agent layer was set by continuously drying at 120 degrees for 1 minute. Thereby a first release film is obtained. The calculated surface average roughness Ra and the maximum of the surface of the first release film in the direction of the first release agent layer and the surface of the first substrate film (the surface opposite to the surface in contact with the adhesive layer) The protrusion height Rp is also from the reference surface of the surface of the first release film in the direction of the first release agent layer The ratio of the unevenness outside the range of 0.2 μm is shown in Tables 1-1 to 1-3.

The preparation of the first release agent layer-forming composition A will be described below.

An anthrone resin solution containing an organic polysiloxane having a vinyl group and an organopolyoxane having a hydrogenated hydrosilyl group (manufactured by Dow Corning Toray, trade name "BY24-561", a solid content of 30 The mass percentage) is 30 parts by mass based on the solid content, and the MQ resin having a vinyl group (manufactured by Dow Corning Toray, trade name "SD7292", the solid content is 71% by mass), and 15 masses are calculated as solid content. The mixture was diluted and mixed with a toluene solvent in such a manner that the solid content concentration was 1.0% by mass. A platinum catalyst (manufactured by Dow Corning Toray Co., Ltd., trade name "SRX-212", a solid content of 100% by mass) was added to the solution in an amount of 2 parts by mass to prepare a composition for forming a first release agent layer. A.

The production of the second release film will be described below.

A polyethylene terephthalate (PET) film (thickness: 38 μm, arithmetic mean roughness Ra: 19 nm, maximum protrusion height Rp: 194 nm) having the same roughness on the back surface was prepared as a second substrate film.

Next, a second release agent layer-forming composition B having the following composition was applied to a surface of the second substrate film by a bar coater in a thickness of 0.1 μm after drying to Celsius The second release agent layer was set by continuously drying at 120 degrees for 1 minute. Thereby, a second release film is produced. The calculated average roughness Ra and the maximum of the surface of the second release film in the direction of the second release agent layer and the surface of the second substrate film (the surface opposite to the surface in contact with the adhesive layer) High protrusion The degree of the Rp and the surface of the second release film in the direction of the second release agent layer from the reference surface ± 0.2 μm are shown in Tables 1-1 to 1-3.

The preparation of the second release agent layer-forming composition B will be described below.

Anthrone resin (manufactured by Shin-Etsu Chemical Co., Ltd.: trade name "KS-847H", solid content concentration: 30% by mass), 100 parts by mass, and platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd.: trade name "CAT-PL50T" 1 part by mass of the solid content concentration of 100 parts by mass, and the above-mentioned composition of the release agent layer B was prepared by diluting the above toluene to prepare a second release agent layer-forming composition B having a solid content concentration of 1.

The production of the adhesive composition will be described below.

99.0 parts by mass of n-butyl acrylate, 1.0 parts by mass of 4-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate and 0.08 2,2' azobisisobutyronitrile-(2-2'-azobisisobutyronitrile) is added to a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen introduction tube, and the reaction is replaced with nitrogen. The air inside the container. Under the nitrogen atmosphere, the reaction solution was heated to 60 ° C while stirring, and after reacting for 16 hours, the reaction liquid was cooled to room temperature. At this time, a part of the obtained solution was measured by a GPC method, and it was confirmed that the produced polymer (A) had a mass average molecular weight of 1.6 million. To 100 parts by mass (solid content) of the above polymer (A), 0.15 parts by mass of a polyisocyanate crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "TAKENATE D-110N") was added, and the solid content concentration was Quality of 75 Percentage) and 0.1 parts by mass of a decane coupling agent ("KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd., a solid content concentration of 100% by mass), and added toluene as a solvent to adjust the solid content to 15% by mass. And the adhesive composition A is prepared.

Here, the mass average molecular weight is a value obtained by a gel permeation chromatography (GPC) method and converted to a value converted by polystyrene.

The production of the double-sided adhesive sheet will be described below.

The adhesive composition A was applied onto the release agent layer of the first release film so as to have a thickness of 25 μm after drying, and dried at 90 ° C for 1 minute to form an adhesive layer. Next, the second release film is attached to the adhesive layer at a rate of 50 m per minute under normal temperature conditions in such a manner that the release agent layer of the second release film contacts the formed adhesive layer. A double-sided adhesive sheet was prepared by sandwiching a silicone gum roll (glue hardness: 80) adjusted to a lamination pressure of 0.5 MPa and a metal roll. Thereafter, the curing was continued for 10 days under conditions of 23 degrees Celsius and 50% relative humidity.

Embodiment 2 will be described below.

A double-sided adhesive sheet was produced in the same manner as in the above-mentioned Example 1, except that the second release film obtained in the following manner was used.

A polyethylene terephthalate (PET) film having the same roughness on the back surface of the surface (thickness: 38 μm, arithmetic mean roughness Ra: 40 nm, maximum protrusion height Rp: 495 nm) was prepared.

Next, for the outer surface of the above PET film, coating with a bar coater The resin layer-forming composition A was dried at 150 ° C for 40 seconds to cure the resin material, and a second base film was produced by forming a resin layer having a thickness of 0.6 μm.

Among them, the resin layer-forming composition A is a mixed solvent of toluene/methyl ethyl ketone (MEK) in which a crosslinking agent and a catalyst are added to a main component (toluene: methyl ethyl ketone (mass ratio) = 50:50) diluted and obtained, wherein an ester resin solution of a bisphenol A (BPA) type epoxy resin (solid content concentration of 60% by mass): 100 parts by mass as a main agent , methylated melamine resin (solid content concentration of 100% by mass): 40 parts by mass as a crosslinking agent, p-toluenesulfonic acid in methanol solution (solid content concentration of 50 Percent by mass): 5 parts by mass as a catalyst.

Next, the second release agent composition B was applied to the surface of the second base film opposite to the direction in which the resin layer was formed by a bar coater so as to have a thickness of 0.1 μm after drying (PET film) Direction), the second release agent layer was set by continuously drying at 120 degrees Celsius for 1 minute, thereby producing a second release film.

The calculated average roughness Ra and the maximum of the surface of the second release film in the direction of the second release agent layer and the surface of the second substrate film (the surface opposite to the surface in contact with the adhesive layer) The protrusion height Rp and the ratio of the surface of the second release film in the direction of the second release agent layer from the reference surface ± 0.2 μm are described in Tables 1-1 to 1-3. .

Embodiment 3 will be explained below.

A double-sided adhesive sheet was produced in the same manner as in the above Example 2 except that the thickness of the resin layer of the second base film was changed to 0.8 μm.

Embodiment 4 will be explained below.

A double-sided adhesive sheet was produced in the same manner as in the above-described Example 2 except that the thickness of the resin layer of the second base film was changed to 0.5 μm.

Embodiment 5 will be explained below.

In addition to changing the second substrate film of the second release film to a polyethylene terephthalate (PET) film having the same roughness on the front and back surfaces (thickness 38 μm, arithmetic mean roughness Ra: 32 nm, maximum protrusion height Rp: A double-sided adhesive sheet was produced in the same manner as in the above-described Example 1 except for 230 nm.

Embodiment 6 will be explained below.

In addition to changing the second substrate film of the second release film to a polyethylene terephthalate (PET) film having the same roughness on the front and back surfaces (thickness 38 μm, surface of the second release agent layer direction (calculus average roughness) Degree Ra: 40 nm, maximum protrusion height Rp: 900 nm), the surface opposite to the second release agent layer (arithmetic average roughness Ra: 19 nm, maximum protrusion height Rp: 194 nm), and the rest are the same as the foregoing examples 1 Make a double-sided adhesive sheet in the same way.

Example 7 will be explained below.

In addition to changing the second substrate film of the second release film to a polyethylene terephthalate (PET) film having the same roughness on the front and back surfaces (thickness 38 μm, arithmetic mean roughness Ra: 15 nm, maximum protrusion height Rp: A double-sided adhesive sheet was produced in the same manner as in the above Example 1 except for 131 nm.

Embodiment 8 will be explained below.

In addition to changing the first substrate film of the first release film and the second substrate film of the second release film to a polyethylene terephthalate (PET) film having the same roughness on the front and back surfaces (thickness 38 μm, arithmetic) A double-sided adhesive sheet was produced in the same manner as in the above Example 1 except that the average roughness Ra: 10 nm and the maximum protrusion height Rp: 93 nm.

Comparative Example 1 will be described below.

In addition to changing the second substrate film of the second release film to a polyethylene terephthalate (PET) film having the same roughness on the front and back surfaces (thickness 38 μm, arithmetic mean roughness Ra: 40 nm, maximum protrusion height Rp: A double-sided adhesive sheet was produced in the same manner as in the above Example 1 except for 535 nm.

Comparative Example 2 will be described below.

In addition to changing the first substrate film of the first release film and the second substrate film of the second release film to a polyethylene terephthalate (PET) film having the same roughness on the front and back surfaces (thickness 38 μm, arithmetic) A double-sided adhesive sheet was produced in the same manner as in the above Example 1 except that the average roughness Ra: 40 nm and the maximum protrusion height Rp: 535 nm.

Comparative Example 3 will be described below.

A double-sided adhesive sheet was produced in the same manner as in the above-mentioned Example 1, except that the second release film obtained in the following manner was used.

Preparation of polyethylene terephthalate (PET) film of the same roughness on the back surface of the surface (thickness 38 μm, arithmetic mean roughness Ra: 19 nm, maximum protrusion) Height Rp: 405 nm).

Next, the resin layer-forming composition A was applied to the outer surface of the PET film by a bar coater, and dried at 150 ° C for 40 seconds to cure the resin material, thereby forming a resin layer having a thickness of 0.6 μm. a second substrate film.

Among them, the resin layer-forming composition A is a mixed solvent of toluene/methyl ethyl ketone (MEK) in which a crosslinking agent and a catalyst are added to a main component (toluene: methyl ethyl ketone (mass ratio) = 50:50) diluted and obtained, wherein an ester resin solution of a bisphenol A (BPA) type epoxy resin (solid content concentration of 60% by mass): 100 parts by mass as a main agent , methylated melamine resin (solid content concentration of 100% by mass): 40 parts by mass as a crosslinking agent, p-toluenesulfonic acid in methanol solution (solid content concentration of 50 Percent by mass): 5 parts by mass as a catalyst.

Next, the second release agent composition B was applied by a bar coater to the surface of the second base film opposite to the surface on which the resin layer was formed by drying to a thickness of 0.1 μm (PET film) Direction), the second release agent layer was set by continuously drying at 120 degrees Celsius for 1 minute, thereby producing a second release film.

Comparative Example 4 will be described below.

A double-sided adhesive sheet was produced in the same manner as in the above Comparative Example 2, except that the thickness of the release agent layer of the second release film was changed to 0.6 μm.

Comparative Example 5 will be described below.

In addition to changing the second substrate film of the second release film to a polyethylene terephthalate (PET) film having the same roughness on the front and back surfaces (thickness 38 μm, arithmetic mean roughness Ra: 4 nm, maximum protrusion height Rp: A double-sided adhesive sheet was produced in the same manner as in the above Example 1 except for 35 nm.

Wherein, the first release film and the second release film of the double-sided adhesive sheet used in each of the examples and the comparative examples, the surface of the adhesive layer direction and the surface of the base film direction (with the adhesive layer) The arithmetic mean roughness Ra and the maximum protrusion height Rp of the surface in the opposite direction of the contact surface are the surface roughness measuring machine SV3000S4 (stylus type) manufactured by Mitutoyo Co., Ltd. and in accordance with Japanese Industrial Standard JIS B 0601. -1994 determination.

The first release film and the second release film used in the double-sided adhesive sheets of the respective examples and the comparative examples are on the surface in the direction of the adhesive layer from the reference surface ± 0.2 μm. The ratio of the unevenness was determined by using the optical interference type surface shape observation device "Wyko NT-1100" (manufactured by Veeco Co., Ltd.), and stitching was performed at a magnification of 2.5 in the VSI mode, and the obtained 4 × 4 mm was obtained. In the surface shape profile in the range, the contour map is binarized so as to be divided into a portion outside the range of ±0.2 μm from the reference surface and a portion within the range of ±0.2 μm to calculate the reference surface ± The ratio of the area occupied by the unevenness of the portion outside the range of 0.2 μm.

In addition, the release force of each of the first release film and the second release film used in the double-sided adhesive sheets of the respective examples and the comparative examples for the adhesive layer was double-sided according to Japanese Industrial Standard JIS-Z0237. The adhesive sheet is cut into a width of 25mm and the length is 200 mm was measured by stretching the first release film or the second release film in a direction of 180 degrees at a speed of 300 mm per minute using a tensile tester in a state where the adhesive layer was fixed.

In the double-sided adhesive sheet used in each of the examples and the comparative examples, the first surface (the first release film direction) and the second surface (the second release film direction) of the adhesive layer were each measured from the reference. The area occupied by the unevenness outside the range of ±0.2 μm. If the surface of the adhesive layer is smooth, this value will be close to 0%. The optical interference type surface shape observation device "Wyko NT-1100" (manufactured by Veeco Co., Ltd.) was used to splicing at a magnification of 2.5 in the VSI mode. In the obtained surface shape profile in the range of 4 × 4 mm, the contour map is binarized so as to be divided into a portion outside the range of ±0.2 μm from the reference surface and a portion within the range of ±0.2 μm. The area ratio of the unevenness in the portion outside the range of ±0.2 μm from the reference surface was calculated.

The results are shown in Tables 1-1~1-3.

The evaluation of each of the examples and the comparative examples will be described below.

Evaluation of the double-sided adhesive sheet obtained as described above was carried out below.

The surface state appearance evaluation (visual) of the first surface of the adhesive layer will be described below.

The second release film of the double-sided adhesive sheet of each of the examples and the comparative examples was peeled off, and the exposed adhesive layer was attached to a black acrylic plate (manufactured by MITSUBISHI RAYON Co., Ltd.). After that, the first release film is stripped, and the light of the fluorescent lamp is reflected for observation, and the image of the fluorescent lamp that is illuminated looks In the case of no distortion, it was judged that the appearance was good (A), and it was judged that the appearance was poor (B) when it was distorted.

The surface state appearance evaluation (visual) of the second surface of the adhesive layer will be described below.

The second release film of the double-sided adhesive sheet of each of the examples and the comparative examples was peeled off and placed on a black acrylic plate (manufactured by MITSUBISHI RAYON Co., Ltd.) with the exposed adhesive layer facing upward. On the other hand, the light of the fluorescent lamp is reflected for observation, and the image of the fluorescent lamp that is illuminated is judged to be good in appearance (A), and it is judged that the appearance is poor (B).

The evaluation of the amount of static electricity taken out of the release film cylinder will be described below.

The "explosion-proof type electrostatic potential measuring device KSD-0108" manufactured by Kasuga Electric Co., Ltd. was used for the amount of static electricity when the release film obtained in each of the examples and the comparative examples was taken up in a roll shape and then taken out from each of the release films. Determination. Less than 5kV is indicated as "A", 5 or more is less than 10kV and is indicated as "B", and 10kV or more is indicated as "C".

Among them, this evaluation is based on Condition 1: "After each release film is produced, it is stored for 10 days in an environment of 23 degrees Celsius and a relative humidity of 50%" and Condition 2: "After each release film is produced, it is 40 degrees Celsius. Under the conditions of continuous storage for 10 days in the environment.

The evaluation of the transfer phenomenon called crying separation will be described below.

The double-sided adhesive sheet of each of the examples and the comparative examples was wound into a roll form having a width of 500 mm, and when the second release film was peeled off by 10 m under conditions of a peeling speed of 10 m per minute and a peeling angle of 90 degrees, Visually confirm adhesion Whether the agent is transferred to the second release film and judged by the following evaluation criteria.

Among them, this evaluation is based on Condition 1: "After each release film is produced, it is stored for 10 days in an environment of 23 degrees Celsius and a relative humidity of 50%" and Condition 2: "After each release film is produced, it is 40 degrees Celsius. Under the conditions of continuous storage for 10 days in the environment.

A: No transfer to the second release film.

B: Transfer to the second release film occurs.

The cake evaluation will be explained below.

The release film obtained by each of the examples and the comparative examples had a width of 1,290 mm and a length of 6000 m, and was wound into a roll shape. The release film roll was continuously stored for 10 days in an environment of 23 degrees Celsius and a relative humidity of 50%, and the appearance of the release film roll was visually observed. No change is shown as no agglomeration phenomenon (A) when it is wound into a roll shape, and a case where half or less has a color tone change is represented by a plurality of agglomerates (B), and a half of the area has a color tone change. Expressed as having agglomeration (C).

Among them, this evaluation is based on Condition 1: "After each release film is produced, it is stored for 10 days in an environment of 23 degrees Celsius and a relative humidity of 50%" and Condition 2: "After each release film is produced, it is 40 degrees Celsius. Under the conditions of continuous storage for 10 days in the environment.

The increase in the release force at the core portion of the release film will be described below.

The release film obtained by each of the examples and the comparative examples had a width of 1,290 mm and a length of 6000 m, and was wound into a roll shape.

The release film roll was stored under the following conditions 1, 2, and the release force of the surface portion of the release film roll and the core portion (in the above test method) was measured, and the core portion/surface portion was numerically quantized.

Among them, this evaluation is based on Condition 1: "After each release film is produced, it is stored for 10 days in an environment of 23 degrees Celsius and a relative humidity of 50%" and Condition 2: "After each release film is produced, it is 40 degrees Celsius. Under the conditions of continuous storage for 10 days in the environment.

A: Less than 1.1.

B: 1.1 or above did not reach 1.3.

C: 1.3 or more.

These results are shown in Tables 2-1~2-2.

As is apparent from Table 2, the double-sided adhesive sheet of the present invention prevents the occurrence of orange peel and does not cause a problem of poor appearance. Moreover, the double-sided adhesive sheet of the present invention optimizes the release property, blocking resistance and antistatic property of each of the release films. Furthermore, the double-sided adhesive sheet of the present invention prevents the occurrence of a sticky phenomenon called crying separation.

On the contrary, the comparative example did not give satisfactory results.

1‧‧‧Double-sided adhesive sheet

10‧‧‧Adhesive layer

101‧‧‧ first surface

102‧‧‧ second surface

11‧‧‧First release film

111‧‧‧First release agent layer

112‧‧‧First substrate film

12‧‧‧Second release film

121‧‧‧Second release agent layer

122‧‧‧Second substrate film

Claims (5)

A double-sided adhesive sheet comprising: an adhesive layer having a first surface and a second surface; a first release film attached to the first surface of the adhesive layer; and a second release a film attached to the second surface of the adhesive layer; wherein the release force of the second release film from the adhesive layer is less than the peeling of the first release film from the adhesive layer a surface force; wherein, the surface of the first release film and the surface of the second release film opposite to the surface of the adhesive layer has an arithmetic mean roughness Ra of 5 to 35 nm and a maximum protrusion height thereof Rp is 50~400nm. The double-sided adhesive sheet according to claim 1, wherein a ratio of the unevenness outside the range of ±0.2 μm from the reference surface to the first surface of the adhesive layer is 20% or less. The double-sided adhesive sheet according to claim 1, wherein a ratio of the unevenness outside the range of ±0.2 μm from the reference surface to the second surface of the adhesive layer is 20% or less. The double-sided adhesive sheet according to claim 1, wherein the adhesive constituting the adhesive layer is a (meth)acrylic acid ester copolymer. The double-sided adhesive sheet according to any one of claims 1 to 4, wherein the release force of the first release film peeled off from the adhesive layer is expressed as X [mN/25 mm], and the second When the release force of the release film peeled off from the adhesive layer is expressed as Y [mN / 25 mm], the relationship of XY ≧ 5 is satisfied.