JP7166706B2 - Thin film support adhesive film - Google Patents

Description

The present invention is an adhesive used to reinforce thin film substrates and thin film sheets in order to facilitate handling of the parts during processes including heating processes in the manufacture and processing of parts using thin film substrates and thin film sheets. Regarding film.

In recent years, devices (electronic devices) such as solar cells (PV), liquid crystal panels (LCD), and organic EL panels (OLED) are becoming thinner and lighter. Thinning is progressing. If the strength of the glass substrate is insufficient due to thinning, it becomes difficult to handle the glass substrate in device manufacturing and processing steps.

In addition, there is a demand for a thin film in the manufacturing and processing steps of semiconductors, circuit boards, and the like. Specifically, semiconductor chips themselves, substrates on which semiconductor chips are mounted and bonded, and flexible substrates for electronic circuits mainly made of polyimide or so-called glass epoxy are becoming thinner.

In order to facilitate the handling of these thinned parts, in order to support the thinned parts, an adhesive film with adhesive applied to the base material is attached as a support film to ensure strength. A method is conceivable in which the work is performed and the adhesive film is peeled off after the work is completed. For example, Patent Literature 1 discloses an easily peelable plastic film for improving the handleability and workability of a thin glass substrate. Further, Patent Document 2 discloses an example of a reinforcing film for producing a thin polyimide film.

Furthermore, in the manufacturing and processing processes of these devices and parts, for example, when semiconductors are sealed, circuits are fixed, and protective layers are formed, the resin placed on the substrate is thermally cured. For example, high temperature heating of about 180° C. is performed.

Adhesive films that support parts subjected to such high-temperature heating must have sufficient heat resistance for the base material and adhesive, and the adhesive will adhere to the parts when the adhesive film is peeled off after passing through a high-temperature environment. It is necessary not to cause so-called adhesive residue. However, Patent Document 1 does not consider heat resistance as described above.

Further, Patent Document 2 describes a pressure-sensitive adhesive layer in a reinforcing film in consideration of heat resistance, and discloses an example of a silicone-based pressure-sensitive adhesive layer in Examples. However, as an adherend of the pressure-sensitive adhesive layer in Patent Document 2, only a thin film of a capacitor material or a piezoelectric material made of a metal, a semiconductor, or a metal compound is disclosed as a functional thin film layer. No consideration is given to heat resistance (adhesive residue) when a thin film containing an organic substance is used as an adherend.

In fact, the present inventors prepared an adhesive film in which a silicone-based pressure-sensitive adhesive layer was directly placed on a substrate made of a resin having a Tg of 85° C. or higher as a heat-resistant substrate, based on Patent Document 2. Experiments were carried out by attaching the adherend directly to the adhesive layer as a thin film of polyimide or glass epoxy. was confirmed. Even when a base material subjected to an easy-adhesion treatment such as corona treatment was used, the degree of adhesive residue was improved, but the problem could not be completely solved.

JP-A-2001-97733 JP 2009-154293 A

The present invention is applicable not only to adherends consisting of only inorganic substances, but also to adherends consisting of organic substances and adherends containing organic substances. To provide a silicone-based adhesive film which can be easily peeled without peeling.

As a result of intensive studies, the present inventors have found that a resin having a Tg of 85° C. or higher is used for the base material, and one surface of the base material is made of a silicone resin obtained by curing a silicone composition through an addition reaction. In an adhesive film having a silicone pressure-sensitive adhesive layer, by providing an easy-adhesion layer composed of a specific composition between the base material and the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer can be applied to the adherend at a high temperature. It has become possible to provide an adhesive film that can be easily peeled from an adherend without leaving adhesive residue even after exposure to environmental conditions.

A first invention is an adhesive film in which an easy-adhesion layer and an adhesive layer are laminated in this order on one side of a substrate made of a resin having a Tg of 85° C. or higher, wherein the adhesive layer cures a silicone composition through an addition reaction. wherein the easy-adhesion layer contains 40 to 85% by weight of silica, 10 to 30% by weight of acrylic urethane resin, and 5 to 30% by weight of ethyl silicate. is.

In the second invention, the pressure-sensitive adhesive layer is formed by curing a silicone composition containing at least a vinyl group-containing polydimethylsiloxane composition, an organohydrogenpolysiloxane having an SiH group, and a silicone resin as the silicone composition through an addition reaction. The adhesive film according to the first invention, characterized in that it is made of a silicone resin consisting of:

A third invention is the adhesive film according to the first invention or the second invention, wherein the easily adhesive layer contains 1 to 30% by weight of polystyrene sulfonic acid.

A fourth invention is the adhesive film according to any one of the first to third inventions, wherein the easily adhesive layer has a thickness of 0.01 to 3.00 μm.

The adhesive film of the present invention comprises a base material made of a resin having a Tg of 85° C. or higher, and an easy-adhesion layer and a silicone-based pressure-sensitive adhesive layer provided in this order, and is an adherend used as a support film for manufacturing thin-film parts. Even after passing through a high-temperature environment during the process, it can be easily peeled off from an adherend without adhesive residue.

The adhesive film of the present invention will be described in more detail below based on its constituent elements.

(overall structure)
The adhesive film of the present invention comprises a substrate made of a resin having a Tg of 85° C. or higher, an easy-adhesion layer provided on one side of the substrate, and a silicone composition cured thereon by an addition reaction. It is an adhesive film provided with a silicone pressure-sensitive adhesive layer made of a silicone resin.

(Base material)
Among the constituent elements of the adhesive film of the present invention, a resin that is heat-resistant and can withstand high-temperature heating is used as the base resin. Specifically, resins having a Tg of 85° C. or higher can be favorably used, and resins such as polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), and polyphenylene sulfide (PPS) can be mentioned. Among them, polyetherimide is particularly favorably used because of its heat resistance, adhesiveness with the easily adhesive layer, and availability of a film as a base material.

The thickness of the substrate is preferably 12-200 μm, more preferably 25-125 μm. If the thickness of the base material is less than 12 μm, the strength as a support film during processing is insufficient. If the thickness is more than 200 μm, the flexibility will be lost and the peeling from the adherend will be difficult. Moreover, the adherend may be damaged during peeling, resulting in a high price.

The surface of the substrate may be subjected to a treatment such as corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, flame treatment, etc., as desired.

(Easy adhesion layer)
In the present invention, an easy-adhesion layer is provided between the substrate and the pressure-sensitive adhesive layer. Examples of materials for the easy adhesion layer include polyester resins, acrylic resins, urethane resins, and various additives. It becomes possible to maintain the adhesion between the adhesive layer and the adhesive base material and the silicone-based pressure-sensitive adhesive layer. Furthermore, by containing silica in the easy-adhesion layer, the adhesive layer leaves an adhesive residue on the adherend when the adhesive film is peeled off from the adherend even after being subjected to a high-temperature environment after being adhered to the adherend. It becomes a heat-resistant and easy-adhesion layer.

The thickness of the easy adhesion layer is preferably 0.01 to 3.00 μm, more preferably 0.03 to 1.50 μm. If the thickness of the easy-adhesion layer is less than 0.01 μm, the adhesive strength between the substrate of the easy-adhesion layer and the pressure-sensitive adhesive layer is insufficient, making it difficult to obtain desired performance. If the thickness is more than 3.00 μm, the adhesive film loses flexibility and becomes difficult to handle. Also, the price will be higher.

The type of silica used in the easy-adhesion layer of the present invention is not particularly limited, and general dry silica and wet silica can be used. Colloidal silica obtained by a so-called wet manufacturing method can be suitably used in that it can be uniformly dispersed in the easy-adhesion layer and can exert its function.

The content of silica in the easy-adhesion layer is preferably in the range of 40 to 85% by weight. Within this range, the easily adhesive layer has sufficient heat resistance, and when the adhesive film and the adherend are peeled off after the adhesive film is adhered to the adherend and passed through a high-temperature environment. In addition, the adhesive layer does not leave any adhesive residue on the adherend. If the content is less than 40% by weight, sufficient heat resistance in the present invention cannot be obtained, and when the adhesive film is peeled from the adherend after passing through a high temperature environment, the pressure-sensitive adhesive layer does not adhere to the adherend. Adhesive residue may occur. If the content exceeds 85% by weight, the content of acrylic urethane resin and ethyl silicate will be relatively small, and the adhesion between the substrate and the easy-adhesion layer, and between the easy-adhesion layer and the silicone pressure-sensitive adhesive layer will be low. Therefore, when the adhesive film of the present invention is attached to an adherend and handled, the adhesive film may be peeled off, or when the adhesive film and the adherend are peeled off after being exposed to a high temperature environment, the pressure-sensitive adhesive Adhesive residue on the adherend of the layer may occur.

The acrylic urethane resin used in the easy-adhesion layer of the present invention forms an easy-adhesion layer by thermally bonding with ethyl silicate in the easy-adhesion layer, and strengthens the adhesion between the substrate and the adhesive layer. Acrylic urethane resins capable of reacting with ethyl silicate are preferred.

The content of the acrylic urethane resin in the easy-adhesion layer in the present invention is preferably in the range of 10 to 30% by weight. If the content is less than 10% by weight, the adhesive strength of the easy-adhesion layer to the base material is insufficient, making it difficult to obtain desired performance. When the content exceeds 30% by weight, the amount of silica and/or ethyl silicate relatively decreases. If the amount of silica decreases, sufficient heat resistance in the present invention cannot be obtained, and when the adhesive film and the adherend are peeled off after passing through a high temperature environment, the adhesive layer leaves an adhesive residue on the adherend. can occur. When the amount of ethyl silicate is reduced, the adhesive strength between the silicone-based pressure-sensitive adhesive layer and the easy-adhesion layer, which will be explained later, is lowered, and the adhesive film may peel off during handling of the adherend to which the adhesive film is attached. Adhesive residue may occur when peeled off after passing through the environment.

The acrylic urethane resin can be obtained by reacting a hydroxyalkyl (meth)acrylate having a hydroxyl group and a (meth)acryloyl group with an isocyanate. It can also be obtained by reacting a polyurethane chain having an isocyanate group at its end, which is produced by the reaction of a diol and an isocyanate, with a hydroxyalkyl (meth)acrylate having a hydroxyl group and a (meth)acryloyl group.

The hydroxyalkyl (meth)acrylates having a hydroxyl group and a (meth)acryloyl group include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy Examples include, but are not limited to, butyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, pentaerythritol tri(meth)acrylate and 1,4-cyclohexanedimethanol mono(meth)acrylate. These compounds may be used singly or in combination of two or more.

Examples of the isocyanate include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethylene diisocyanate, and adducts, biurets, and isocyanurates in which three molecules of these isocyanate monomers are bonded. Examples include, but are not limited to, bodies. These compounds may be used singly or in combination of two or more.

Examples of the diols include polycarbonate diols, polyester diols, polyether diols, and the like, but are not limited to these. These compounds may be used singly or in combination of two or more.

Moreover, the easy-adhesion layer of the present invention contains ethyl silicate. By containing ethyl silicate, the adhesive strength between the easy-adhesion layer and the silicone pressure-sensitive adhesive layer becomes a sufficient value in the present invention.

The content of the ethyl silicate in the easy-adhesion layer is preferably in the range of 5 to 30% by weight. If the content is less than 5% by weight, the adhesion between the easy-adhesion layer and the silicone-based pressure-sensitive adhesive layer is insufficient, making it difficult to obtain the desired performance. If the content exceeds 30% by weight, the amount of silica and/or acrylic urethane resin is relatively decreased. If the amount of silica decreases, sufficient heat resistance in the present invention cannot be obtained, and when the adhesive film and the adherend are peeled off after passing through a high temperature environment, the adhesive layer leaves an adhesive residue on the adherend. can occur. When the amount of the acrylic urethane resin decreases, the adhesive strength between the base material and the easy-adhesion layer decreases. When the adhesive film and the adherend are peeled off after passing through, the adhesive layer may leave an adhesive residue on the adherend.

Moreover, in the thermal bonding between the acrylic urethane resin and the ethyl silicate, a polyanion may be contained as an acidic catalyst for promoting the reaction. By containing a polyanion, the speed of the reaction can be increased. Among the polyanions, polystyrene sulfonic acid can be preferably used from the viewpoint of the heat resistance and flexibility of the easy-adhesion layer and the adhesion to the substrate and the pressure-sensitive adhesive layer.

The content of the polystyrene sulfonic acid in the easy-adhesion layer is preferably 1 to 30% by weight. If the content is less than 1% by weight, it is difficult to obtain the desired performance. If the content exceeds 30% by weight, the ratio of one of the other components will be relatively low, and the function of the other component whose content ratio is low is heat resistance in the case of silica, and easy to use as the base material in the case of acrylic urethane resin. The adhesive strength of the adhesive layer, and the adhesive strength of the easy-adhesive layer and the pressure-sensitive adhesive layer decreases in the case of ethyl silicate. As a result, the adhesive film of the present invention may be peeled off during handling of an adherend to which the adhesive film is adhered, or when the adhesive film is peeled off from the adherend after passing through a high-temperature environment, the pressure-sensitive adhesive layer may be damaged. Adhesive residue may be left on the adherend.

(Adhesive layer)
The pressure-sensitive adhesive layer of the adhesive film of the present invention is required to be reliably adhered to an adherend and to be peelable without adhesive residue even after exposure to a high-temperature environment. As the adhesive layer for such applications, resins such as natural and synthetic rubbers, silicone resins, urethane resins, acrylic resins, and resins obtained by curing these individual resins with a curing agent can be used. Because of its flexibility, an addition reaction type silicone resin obtained by curing a silicone composition through an addition reaction with heat is particularly suitable for use. Adhesive film that can be easily peeled off from the adherend without adhesive residue even after being exposed to a high-temperature environment by forming an adhesive layer with an addition-reactive silicone resin and combining it with the base material and the easy-adhesion layer of the present invention. can be

The addition reaction type silicone resin used in the pressure-sensitive adhesive layer of the present invention includes polyorganosiloxane and silicone resin having two or more vinyl groups in one molecule as a silicone composition, and an organo resin having a SiH group as a curing agent. A material obtained by thermally curing the hydrogen polysiloxane through an addition reaction is preferably used. A suitable pressure-sensitive adhesive layer can be obtained by containing the above-mentioned polyorganosiloxane, the above-mentioned silicone resin, and the above-mentioned organohydrogenpolysiloxane having an SiH group as a silicone composition and thermally curing the composition.

The pressure-sensitive adhesive layer using a silicone resin will be described in more detail below.

(Silicone resin adhesive layer)
As for the properties of the silicone resin used for the pressure-sensitive adhesive layer of the present invention, it is required that the surface of the pressure-sensitive adhesive layer conforms to the surface of the adherend with rubber-like flexibility. be done. Furthermore, when peeling, it is required that the film can be easily peeled off with a small peeling force. In order to form a pressure-sensitive adhesive layer with a thickness of at least 5 µm or more only by coating and heat treatment, the curing reaction of the silicone composition must be carried out at a low temperature of 150°C or less for a short period of time under an addition reaction catalyst such as a platinum catalyst. Diorgan polysiloxane and silicone resin having two or more vinyl groups per molecule, which are transparent, heat resistant, have excellent compression set properties, are liquid type with low viscosity, and cure to the deep part, and as a curing agent. It is preferred to use an addition reaction type liquid silicone composition which is heat cured by an addition reaction with an organohydrogenpolysiloxane having SiH groups.

The diorganopolysiloxane having two or more vinyl groups per molecule includes a linear diorganopolysiloxane having vinyl groups only at both ends and a linear diorganopolysiloxane having vinyl groups at both ends and side chains. It is preferable to use at least one selected from organopolysiloxane, branched diorganopolysiloxane having vinyl groups only at the terminals, and branched diorganopolysiloxane having vinyl groups at terminals and side chains.

One form of these diorganopolysiloxanes is a linear diorganopolysiloxane having vinyl groups only at both ends, and is a compound represented by the following general formula (Chem. 1).

(In the formula, R represents the following organic group, and n represents an integer.)

(In the formula, R represents the following organic group, and n and m represent integers.)

The organic group (R) bonded to the silicon atom other than the vinyl group may be different or the same type. Specific examples include alkyl groups such as methyl group, ethyl group and propyl group, and aryl groups such as phenyl group and tolyl group. , or monovalent hydrocarbon groups excluding the same or different unsubstituted or substituted aliphatic unsaturated groups in which some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms, cyano groups, etc. Preferably, at least 50 mol % of the diorganopolysiloxane is a methyl group, and this diorganopolysiloxane may be used alone or in combination of two or more.

Linear diorganopolysiloxane having vinyl groups at both ends and side chains is a compound in which part of R in the general formula (1) is a vinyl group. A branched polyorganosiloxane having vinyl groups only at the terminals is a compound represented by the general formula (2). A branched polyorganosiloxane having vinyl groups at its terminals and side chains is a compound in which part of R in the general formula (2) is a vinyl group.

The weight average molecular weight of the diorganopolysiloxane having two or more vinyl groups per molecule is preferably in the range of 20,000 to 700,000. When the weight-average molecular weight of the diorganopolysiloxane is less than 20,000, the curability is lowered and the adhesive strength to adherends is lowered. On the other hand, if it exceeds 700,000, the viscosity of the composition becomes too high, making stirring during production difficult.

The silicone resin used in the adhesive layer of the present invention includes M units (R ₃ SiO _1/2 : R is a monovalent organic group such as a methyl group and a phenyl group) and D units (R ₂ SiO _2/2 ). , T units (RSiO _3/2 ), and Q units (SiO _4/2 ). It is preferable to contain a so-called conventionally known MQ-type organopolysiloxane resin (hereinafter sometimes abbreviated as MQ resin) consisting of units. The content of the MQ resin in the adhesive layer is preferably in the range of 0.01 to 20.00% by weight. A range of 0.10 to 15.00% by weight is particularly preferred. If the content is less than 0.01% by weight, it is difficult to obtain the effect of improving the adhesive strength. If the content exceeds 20.00% by weight, the adhesive strength becomes too strong, and when the pressure-sensitive adhesive layer is peeled from the adherend, the thin film substrate or thin film sheet that is the adherend may be damaged.

In the combination of the diorganopolysiloxane and the silicone resin, the curing agent used for the curing reaction may be a known one, and examples of the curing agent include organohydrogenpolysiloxanes having SiH groups in the molecule. be done. Among them, it is particularly preferable to use a methylhydrogensiloxane-dimethylsiloxane copolymer. The methylhydrogensiloxane portion of the copolymer preferably has at least 3 silicon-bonded hydrogen atoms in one molecule, but from a practical standpoint, those having two ≡SiH bonds in the molecule are preferred. Preferably, the total amount is up to 50% by weight, the remainder containing at least 3 ≡SiH bonds in the molecule. As for the shape of the molecule, linear, branched, and cyclic ones can be used.

Further, the molar ratio (A)/(B) of the SiH groups (B) in the organohydrogenpolysiloxane to the vinyl groups (A) in the diorganopolysiloxane having vinyl groups is 1.0 to 2.0. is preferably blended so as to be in the range of If the molar ratio (A)/(B) is less than 1.0, the cured density may be insufficient, resulting in a decrease in cohesive strength and holding power. As a result, it becomes difficult to obtain a suitable adhesive force, and it becomes difficult to obtain a sufficient adhesive force due to the bonding between the hydroxyl groups and the SiH groups on the surface of the easy-adhesion layer.

The addition reaction catalyst used for the curing reaction is chloroplatinic acid, an alcohol solution of chloroplatinic acid, a reaction product of chloroplatinic acid and alcohol, a reaction product of chloroplatinic acid and an olefin compound, and chloroplatinic acid and vinyl group-containing siloxane. reaction products, platinum-olefin complexes, platinum-vinyl group-containing siloxane complexes, rhodium complexes, ruthenium complexes, and the like. Alternatively, these substances may be used by dissolving or dispersing them in a solvent such as isopropanol or toluene, silicone oil or the like. The cured pressure-sensitive adhesive layer becomes flexible like silicone rubber, and this flexibility facilitates adhesion to the adherend.

The addition amount of the addition reaction catalyst is preferably 5 to 2,000 ppm, more preferably 10 to 500 ppm, in terms of noble metal content per 100 parts by weight of the silicone composition. If it is less than 5 ppm, the curability may be lowered, the cured density may be lowered, and the holding power may be lowered.

Commercially available forms of the silicone composition according to the present invention include non-solvent type, solvent type, and emulsion type, and any type can be used. Among them, the non-solvent type is very advantageous in terms of safety, sanitation and air pollution because it does not use a solvent. However, even in the solventless type, aromatic hydrocarbon solvents such as toluene and xylene, and fats such as hexane, heptane, octane, and isoparaffin may be used to adjust the viscosity to obtain the desired film thickness. group hydrocarbon solvents, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and isobutyl acetate, ether solvents such as diisopropyl ether and 1,4-dioxane, and mixed solvents thereof. is used.

The amount of the solvent added is preferably 20 to 1,000 parts by weight, particularly 25 to 900 parts by weight, per 100 parts by weight of the silicone composition. If the amount is less than 20 parts by weight, the adhesion between the adhesive layer and the easy-adhesion layer may deteriorate and the adhesive layer may peel off. During the period from coating to curing, the coated pressure-sensitive adhesive layer partially flows, and the smoothness of the surface of the pressure-sensitive adhesive layer decreases.

The properties of the pressure-sensitive adhesive layer of the present invention are required to have rubber-like flexibility and follow the irregularities of the surface of the adherend when adhered to the adherend to ensure adhesion. And, for example, when used as a support film for manufacturing the above-mentioned parts, the thickness of the adhesive layer is at least 5 μm or more, usually 10 to 100 μm, in order to secure a shearing force in the direction of the adhesion surface of the adhesive layer to the adherend. is preferred, and 20 to 50 μm is more preferred. If the thickness is less than 5 μm, the shearing force in the direction of the contact surface of the protective member against the adherend cannot be ensured, and the adhesive film is easily peeled off from the adherend, especially during long-term application. Moreover, when the thickness of the pressure-sensitive adhesive layer exceeds 100 μm, the amount of the resin constituting the pressure-sensitive adhesive layer used increases, resulting in an increase in the manufacturing cost of the adhesive film.

As a method for forming the adhesive layer in the present invention, there is a method of dissolving the resin constituting the adhesive layer in an organic solvent and applying a resin solution whose viscosity is adjusted, or a method of dispersing the resin constituting the adhesive layer in water. A known method such as a coating method can be used. As the organic solvent, a general organic solvent can be used without particular limitation. Examples include, but are not limited to, organic solvents for adjusting the viscosity described above.

Examples of coating methods for the pressure-sensitive adhesive layer of the present invention include a comma knife coater, a die coater, a reverse coater and the like.

(separator)
In the present invention, it is preferable to use a separator made of a plastic film attached to the surface of the pressure-sensitive adhesive layer for the purpose of preventing contamination and adhesion of foreign matter to the surface of the pressure-sensitive adhesive layer and improving the handling of the adhesive film. The separator is made of a highly releasable plastic film, and if desired, a release agent is formed on the surface of the plastic film.

Examples of the plastic film for the separator include cellophane film, polyester film, polypropylene film, polyethylene film, polycarbonate film, and polystyrene film. The thickness of the plastic film is preferably 25-200 μm. If the thickness is less than 25 μm, the film strength is insufficient, and sufficient protective performance cannot be obtained. On the other hand, if the thickness is more than 200 μm, problems such as difficulty in handling and an increase in the cost of the plastic film itself occur.

As the release agent, a polyolefin-based material such as polyethylene or polypropylene, or a fluorine-based material having a high release effect can be used.

As a method for forming the release agent on the plastic film, the same method as the method for forming the pressure-sensitive adhesive layer on the substrate can be used. Moreover, the surface on which the release agent is formed on the plastic film may be either one surface or both surfaces, as desired.

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In addition, "parts" in each example indicate parts by weight unless otherwise specified.

(Examples 1 to 14, Comparative Examples 1 to 6)
One side of each substrate of Examples 1 to 14 and Comparative Examples 1 to 6 in Table 2 was subjected to corona discharge treatment, and each easy-adhesion layer coating of each Example and Comparative Example mixed according to the formulation shown in Table 2. The liquid was adjusted so that the thickness after drying was each of the values shown in Table 2, applied to the corona discharge-treated surface of each substrate, and heated at 100°C for 2 minutes to remove the organic solvent. Each easy-adhesion layer was formed by drying. Each pressure-sensitive adhesive layer coating solution shown in Table 1 below was coated thereon so that the thickness after drying would be 15 μm, then dried by heating at 100° C. for 2 minutes to remove the organic solvent, and then dried at 150° C. The coating liquid was cured by heating for 100 seconds to form an adhesive layer, and adhesive films of Examples 1 to 14 and Comparative Examples 1 to 6 were produced. Each adhesive film thus prepared was cut into a width of 25 mm, and the pressure-sensitive adhesive layer of each adhesive film was attached to a glass plate or glass epoxy substrate having a thickness of 100 μm, followed by heating at 180° C. for 2 minutes and cooling to room temperature. A laminate was prepared by attaching each adhesive film to a glass plate and a glass epoxy substrate.

単位：重量部

Unit: part by weight

Table 2 shows the material composition ratio and evaluation results of each example and comparative example, and each evaluation method is shown below.

(Evaluation method)

(Adhesion evaluation: Easy adhesion layer)
In the films of Examples 1 to 14 and Comparative Examples 1 to 6 on which the easy adhesion layers were installed, the adhesion between the base material and the easy adhesion layer was visually observed by rubbing the easy adhesion layer with a finger, and evaluated according to the following criteria. did.
A: No detachment from the base material after 50 finger rubbings.
◯: Detachment from the substrate after rubbing with fingers 10 times or more and less than 50 times.
x: Falling off from the base material after less than 10 finger rubbings.

(Adhesion evaluation: adhesive layer)
The adhesive layers of the adhesive films of Examples 1 to 14 and Comparative Examples 1 to 6 were rubbed with a finger to visually observe the adhesiveness between the easily adhesive layer and the adhesive layer, and evaluated according to the following criteria.
A: No detachment from the base material after 15 finger rubbings.
◯: Detachment from the base material after finger rubbing 5 times or more and less than 15 times.
x: Less than 5 rubbings with a finger, falling off from the base material.

(Evaluation of heat resistance and adhesive residue property of adhesive layer)
In the laminates of the glass plate and each adhesive film prepared in Examples 1 to 14 and Comparative Examples 1 to 6, when the adhesive film was peeled at 180° at a speed of 300 mm / min, after peeling the adhesive film Adhesion of the adhesive layer to the glass plate was evaluated by visually confirming the adhesive residue.
Evaluation Criteria ◯: No adhesion of the pressure-sensitive adhesive layer to the glass plate.
x: Adhesion of the pressure-sensitive adhesive layer to the glass plate is observed.

(Peelability evaluation)
In the laminates of the glass epoxy substrate and each adhesive film prepared in Examples 1 to 14 and Comparative Examples 1 to 6, when the adhesive film was peeled at 180° at a speed of 300 mm/min, the adhesive film was It was visually confirmed whether it stuck to the glass epoxy substrate and whether the substrate was broken, and the peelability was evaluated.
Evaluation Criteria ⊚: Easy peeling without occurrence of sticking.
◯: Sticking occurred and could not be easily peeled off, but the glass epoxy substrate did not break.
x: Sticking occurred, and breakage occurred in the glass epoxy substrate.

Claims (4)

An adhesive film in which an easy-adhesion layer and an adhesive layer are laminated in this order on one side of a substrate made of a resin having a Tg of 85° C. or higher, wherein the adhesive layer is made of a silicone resin obtained by curing a silicone composition through an addition reaction. The adhesive film, wherein the easily adhesive layer contains 40 to 85% by weight of silica, 10 to 30% by weight of acrylic urethane resin, and 5 to 30% by weight of ethyl silicate. The pressure-sensitive adhesive layer is made of a silicone resin obtained by curing, by an addition reaction, a silicone composition containing at least a vinyl group-containing polydimethylsiloxane composition, an organohydrogenpolysiloxane having an SiH group, and a silicone resin as the silicone composition. The adhesive film according to claim 1, characterized by: 3. The adhesive film according to claim 1, wherein the easy-adhesion layer contains 1 to 30% by weight of polystyrene sulfonic acid. The adhesive film according to any one of claims 1 to 3, wherein the easily adhesive layer has a thickness of 0.01 to 3.00 µm.