JPH02145669A - Pasting film and film-forming process - Google Patents

Abstract

PURPOSE:To obtain a pasting film which is easily applicable to an adherend to give a pasted film having excellent appearance and adhesivity by using a tacky adhesive composed of a specific curable resin and a curing agent having a curing property different from that of the curable resin and applying the tacky adhesive to one surface of a specific synthetic resin film. CONSTITUTION:One surface of a synthetic resin film having a glass transition point of <=5 deg.C and an elongation of >=3% and made of one or more resins selected from polyimide, bismaleimide, polyamide imide, polyimide epoxy, polyamide, polysiloxane, polyoxadiazole, polybenzimidazole, triazine, polyvinyl fluoride and polyvinylidene fluoride is coated with a tacky adhesive composed of a curable resin having a glass transition point of <=5 deg.C and a curing agent having a curability different from that of the resin. The applied adhesive is cured until the tack value reaches 1-8, bonded to an adherend under pressure and heated to laminate the film to the adherend.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an adhesive film and a method of forming an adhesive film.

(Prior art and its problems) Conventionally, adhesive films with an adhesive layer on one side have been processed with characters, designs, etc., or left unprocessed and adhered to adherends under pressure to create signs, advertising signs, etc. , used for purposes such as decoration and recording.

The properties required of this adhesive are that it has appropriate adhesiveness from the viewpoint of workability and that it does not peel off even when the adherend (e.g. ships, vehicles, buildings, etc.) is exposed to the external environment. It must be satisfied that the adhesion is excellent for a long period of time without any oxidation.

In order to impart the above-mentioned adhesive with appropriate adhesive properties and excellent adhesion to adherends, thermoplastic resins with a low glass transition point and high molecular weight (e.g. rubber-based, acrylic-based, (vinyl type, silicone type, etc.) are used. However, when a film is attached to a high-temperature adherend such as a vehicle or steam pipe, which has a high temperature surface in the summer, the film easily peels off from the adherend due to thermal softening of the adhesive. . Furthermore, if the molecular weight of the resin is increased to such an extent that the adhesive does not cause thermal flow, it becomes difficult to form a thin film of the adhesive M on the film surface, and moreover, when pressure-bonded to an adherend, there is no air on the adhesive surface. This has the drawback that the film is more likely to contain wrinkles, resulting in a film with poor finished appearance.

However, as a method to improve the above-mentioned drawbacks, it is possible to use a thermosetting composition formed by blending a thermosetting resin and a curing agent as an adhesive, but as a curing agent, a curing agent that is reactive at low temperature is used. The film must be attached to the adherend before the reaction between the resin and the curing agent progresses and the adhesive loses its tackiness, so the time it takes to attach the film to the adherend is short. On the other hand, when a high temperature reactive curing agent is used, the adhesive flows and protrudes from the film before being thermally cured, resulting in poor appearance of the film after application.

The present invention was made for the purpose of providing an adhesive film that can be easily applied to an adherend and has excellent appearance and adhesion to the adherend after application, and a method for forming the same. It is something.

(Means for Solving the Problems) As a result of intensive research aimed at resolving these drawbacks, the present inventors have determined that the glass transition point is 50°C or higher and the elongation rate is 3% or higher. The surface of the cured film is coated with an adhesive whose essential components are a curable resin with a glass transition point of 5°C or less and a curing agent with different curability. The present inventors have discovered that a film can be formed that can be pasted, and has excellent appearance after pasting and long-term adhesion to adherends, leading to the completion of the present invention.

That is, the present invention applies to polyimide, bismaleimide, polyamideimide, polyimide epoxy, polyamide, polysiloxane, polyoxadiazole, polypenzimidazole, triazine, polyvinyl fluoride, and polyvinylidene fluoride. at least one selected from
A curable resin (A) with a glass transition point of 5°C or less and a curing agent (B) with different curability are essential components on one side of a synthetic resin film with a glass transition point of 50°C or more and an elongation rate of 3% or more. A pasting film characterized in that it is provided with an adhesive, and the adhesive is applied to one side of a synthetic resin film, the adhesive is cured to a tack value of 1 to 8, and then The present invention relates to a film forming method characterized in that the surface of the adhesive layer is brought into contact with the surface of an adherend and bonded under pressure, followed by heating.

The synthetic resin films used in the adhesive film of the present invention include polyimide, bismaleimide, polyamideimide, polyimide epoxy, polyamide, polysiloxane, polyoxadiazole, polypenzimidazole, triazine, Examples include those based on polyvinyl fluoride and polyvinylidene fluoride. These synthetic resin films can be obtained by applying, for example, a commercially available solution of synthetic resin in an organic solvent or a mixed solution containing a hardening agent to a predetermined film thickness and drying. Can be done. The thickness of the film is 5 to 1000μ, preferably 10 to 500μ.

The temperature of the film is 50°C or higher, preferably 70°C to 400°C.
and 3% or more, preferably 5% to 3
00% elongation rate. If the glass transition point is lower than 50°C, when the film formed on the surface of the adherend is heat-treated, the film will soften, resulting in the formation of displays with different dimensions, or designs with poor appearance such as distortions and wrinkles. There is a disadvantage that the film may form decorations or decorations, and when the film is exposed to a high temperature environment, the mechanical strength of the film is lost.
This is undesirable because it may break, deform, or peel off with a slight external force, and if the elongation rate is less than 3%, it is undesirable because film defects such as cracks and chips are likely to occur during handling.

The elongation rate (tensile elongation rate at break) of the above film was measured using a universal tensile tester with a constant temperature bath (Shimadzu Autograph S-D model).
This is the value when measured at a tensile rate of 20 mm/min at +20° C. using a sample with a length of 20 mm.

In addition, the glass transition point of the film is DAYNAMIC:
VISCOELASTOMETERMODEL VIB
RON DDV-If-EA type (TOYOBALDWI
This is a value measured using NCO, Ltd.

In the present invention, the synthetic resin film may contain an extender, a coloring pigment, a dye, a colorant such as a metal powder, a pigment dispersant, a surface conditioner, an ultraviolet absorber, a plasticizer, a light stabilizer, etc. as necessary. Can be mixed.

The adhesive used in the adhesive film of the present invention is a composition containing a curable resin (A) and a curing agent (B) having different curability as essential components.

The curable resin (A) has a glass transition point of 5° C. or less and has an average of at least two functional groups in one molecule that can react with the curing agent of the curing agent (B) component. be. Examples of the functional group include a hydroxyl group, an epoxy group, a carboxyl group, a methylol group, an alkylmethylol group, and an isocyanate group.

The above functional group may be one type or two types of functional groups that are non-reactive with each other.
Can be used in combination of more than one species.

As the curable resin (A), specifically, for example, an epoxy resin having a hydroxyl group or an epoxy group [e.g., bisphenol-epichlorohydrin type [e.g. Epon 812.815.820.828.834 manufactured by Shell Chemical Co., Ltd., manufactured by Dow Chemical Company] DER-331, DER-337, etc.'', Novolak type ``For example, Dow Chemical Company DEN-431, D
EN-438, etc.", polyalkylene ether type "e.g. DER-732 manufactured by Dow Chemical Co., etc.", fatty acid ester type "e.g. epoxidized soybean oil etc.", aromatic carboxylic acid ester type "e.g. Shodyne 508 manufactured by Showa Denko Co., Ltd. etc.'', alicyclic type [e.g. Chinnox 20 manufactured by Chisonox Co., Ltd.
6, etc.]: Vinyl resins having hydroxyl groups, carboxyl groups, epoxy groups, methylol groups, alkylmethylol groups, isocyanate groups [e.g. hydroxyl group-containing acrylic monomers such as hydroxyethyl (meth)acrylate,
Hydroxypropyl (meth)acrylate, etc.”, carboxyl group-containing vinyl monomers “e.g. (meth)acrylic acid, (anhydride)maleic acid, iconic acid, etc.”, epoxy group-containing acrylic monomers “e.g. glycidyl (meth)acrylate, etc.” , vinyl monomers containing methylol groups or alkylmethylol groups (e.g. N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylamide, etc.), vinyl monomers containing isocyanate groups (e.g. α,α-dimethyl-m-isopropenyl) Polymers or copolymers obtained by copolymerizing one or more monomers having a functional group such as "benzyl isocyanate, etc." with other monomers capable of radical copolymerization as necessary, but the above-mentioned Examples of other monomers include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate.
Examples include acrylate, styrene, vinyltoluene, perfluorooctylethyl methacrylate, perfluoroisononylethyl methacrylate. ]: Polyester or alkyd resin having hydroxyl group or carboxyl group [e.g., polyhydric alcohol such as ethylene glycol, trimethylolpropane, glycerin, polybasic acid such as phthalic acid, isophthalic acid, terephthalic acid, adipic acid, and fatty acid if necessary and phenolic resins having a phenolic hydroxyl group or a phenolic methylol group.

Among the above-mentioned resins, it is preferable to use epoxy resins because a film with excellent adhesion to the adherend, chemical properties, and mechanical properties can be obtained.

The curable resin (A) has a temperature range of 5°C or lower, preferably -20°C.
It has a glass transition point (value determined by differential scanning calorimetry) in the range of 0°C to 0°C. If the glass transition point is higher than 5° C., the adhesiveness of the film in a low-temperature atmosphere will decrease, which is not preferable because the adhesiveness to the adherend during attachment will be poor.

The curing agent (B) used in the present invention is a low temperature reactive curing agent (B
-1) and a high temperature reactive curing agent (B-2). The curing agent (B-1) and the curing agent (B-27
each has an average of at least two functional groups in one molecule, and the functional groups are reactive with the functional groups in the curable resin (A).

As the low temperature reactive curing agent (B-1), a conventionally known curing agent can be used so that the tack value falls within the range of 1 to 8 by heating a film with a tack value of more than 8 at room temperature or a low temperature of about 100°C or less. It can be selected and used as appropriate. The type of the low-temperature-reactive curing agent (B-1) can be appropriately selected depending on the functional group of the curable resin (A) to be combined. B-1)
To give a few examples of combinations with hydroxyl group-containing resins, polyisocyanate compounds [e.g., aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and combinations of these with polyhydric alcohols] adducts etc.], amino resins [e.g. melamine resins,
urea resin, etc.] etc.: For epoxy group-containing resins, examples include polyamine compounds [for example, aliphatic polyamines, alicyclic polyamines, aromatic polyamines, etc.], polymercaptan compounds, polyamide resins, aminopolyamide resins, etc.

The blending ratio of the low-temperature-reactive curing agent (B-1) can be appropriately blended so that the tack value of the film falls within the range of 1 to 8. Specifically, for example, when the functional group of the curable resin (A) to be reacted with the low-temperature-reactive curing agent (B-1) is the same as the functional group to be reacted with the high-temperature-reactive curing agent (B-2), [For example, hydroxyl group-containing vinyl resin as component (A), (, B
-1) A polyisocyanate compound and (B
-2) Combination with block polyisocyanate compound as a component] Even after the reaction between the low temperature reactive curing agent (B-1) and the curable resin (A), the curable resin (A)
It can be blended so that a functional group that reacts with the functional group in the high temperature reactive curing agent (B-2) remains in the curing agent (B-2). In this case, usually
Curing agent (B-1) per functional group of curable resin (A)
) has a functional group number of about 0.05 to 0.7, preferably about 0.
．． It can be blended in a range of 1 to 0.5. In addition, when the functional group of the curable resin (A) to be reacted with the low-temperature-reactive curing agent (B-1) is different from the functional group to be reacted with the high-temperature-reactive curing agent (B-2), [for example, (A) A combination of an epoxy resin containing a hydroxyl group and an epoxy group as a component, a polyisocyanate compound as a component (B-1), and an acid anhydride as a component (B-2)], a low temperature reactive curing agent (B-1)
It can be blended so as to react with some or all of the functional groups of the curable resin (A) that react with the curable resin (A).

The high-temperature-reactive curing agent (B-2) is a curing agent with lower reactivity than the low-temperature curing agent (B-1), and is about 10
It can react at temperatures higher than 0°C, preferably at about 140°C or higher, and can be appropriately selected from conventionally known curing agents. Typical specific examples include, for hydroxyl group-containing resins, blocked products of the polyisocyanate compounds [blocking agents include phenols, alcohols, oximes, lactams, etc.], amino resins, etc.; Examples of resins include (anhydrous) polycarboxylic acids, basic active hydrogen compounds (eg, dicyandiamide, organic acid dihydrazide, etc.).

The blending ratio of the high temperature reactive curing agent (B-2) is such that the number of functional groups in the curing agent (B-2) is approximately 0.3 to 1.5 per functional group of the curable resin (A). , preferably about 0.4-1
．． It seems that 2 pieces is sufficient.

In the film forming method of the present invention, a 100% by weight liquid or organic solvent solution adhesive prepared by blending the curable resin (A) and the curing agent (B) is applied to one side of the synthetic resin film, and the adhesive is This can be carried out by curing the adhesive until it has a tack value within the range of 1 to 8, then applying the adhesive layer surface to the surface of the adherend and adhering it under pressure, followed by heating.

As a method for coating one side of the synthetic 1ii4 fat film, 1, for example, a coating method such as a spray method, an electrostatic spray method, a brush coating method, a flow coating method, a roll coating method, a reverse roll coating method, a knife coating method, etc. may be used. Can be done.

Next, the adhesive layer formed on one side of the synthetic resin film is formed at a temperature at which the curable resin (A) and the low-temperature reactive curing agent (B-1), which are the constituent components of the adhesive, react (for example, about 120°C).
(preferably about 100°C or less) and a tack value of 1 to 8,
It is preferably cured until it reaches a range of 2 to 5. If the tack value is less than 1, the adhesion to the adherend is poor, and there is a risk that it will peel off immediately after pasting, resulting in poor pasting workability and poor adhesion of the final adhesive film. Adhesion to the body is also not sufficient, which is undesirable. On the other hand, if the tack value is greater than 8, the adhesive will protrude from the periphery of the synthetic resin film during heating, resulting in a film with poor appearance, adhesion, etc., which is undesirable.

Furthermore, the adhesive layer of the adhesive film adhered to the surface of the adherend is cured by heating, and it can exhibit good adhesion to many types of adherends, but the heating is performed at approximately 120°C.
As mentioned above, preferably about 140°C to 200°C seems to be sufficient.

The above tack value is calculated by placing the adhesive surface of the sample (length 10 cm, width 2
0cm) is on top. 32 types of bearing balls with inclinations up to h--R inches (32 to 1+ in order from sparrow to
The value of l is the ball N.

This is the value shown by the ball number of the maximum method of the ball that is rolled and stopped on the sticky surface.

In the adhesive film of the present invention, a releasable sheet layer can be provided on the pressure-sensitive adhesive layer surface of the film. The releasable sheet is removed when the adhesive film is pressed onto the surface of the adherend to adhere it. As the sheet, high-quality paper, art paper, coated paper (filler), film laminated paper, cloth, etc. are used. In addition, the sheet treated with a mold release agent such as oil or fat, polyolefin, silicone, or fluorine is used in -R9.

Furthermore, in the adhesive film of the present invention, a colored or printing ink layer and a clear layer may be formed on the surface of the film opposite to the pressure-sensitive adhesive layer, if necessary.

Furthermore, the adhesive film of the present invention can be used by adhering under pressure to adherends such as metal, wood, inorganic materials, plastics, and the like.

(Function and Effects of the Invention) In the adhesive film of the present invention, by using a composition consisting of a curable resin and a curing agent with different curability as an adhesive, it has excellent application workability and is also effective against adherends. The reason for the excellent long-term adhesion effect is presumed to be as follows.

First, when the composition is applied to a synthetic resin film, the reaction between the curable resin and the low-temperature-reactive curing agent proceeds, resulting in an adhesive layer having a tack value within a specific range with excellent workability in pasting.

Next, the adhesive layer of the film attached to the adherend is cured by heating, but since the adhesive layer does not flow due to heat, the adhesive does not protrude from the periphery of the synthetic resin film and the appearance , a film with excellent adhesion is formed. Furthermore, by heating, the reaction between the curable resin and the high temperature reactive curing agent proceeds, and a cured layer having excellent mechanical strength, heat resistance, adhesion to adherends, and adhesion to films is formed.

The adhesive layer of the present invention uses two types of curing agents having particularly different reactivities, so that the functional roles of the respective curing agents are shared.

(Example) The present invention will be described in more detail with reference to Examples below. In the examples, "part" and "r%" are each based on weight.

Preparation of sample (1) Synthetic resin film (a) The following synthetic resin solution was coated with release paper (Shikoku Paper Co., Ltd., 100X 1-
00 mm) using a doctor blade so that the dry film thickness was 10 to 30 μm, and drying was performed under the following conditions to obtain films (a-1) to (a-11). The numbers correspond to the numbers obtained from the synthetic resin solution below.

(a-1): HPC-6000 (manufactured by Hitachi Chemical Co., Ltd.
Product name, polyamideimide resin, solid content 30%), 23
Drying at 0°C for 30 minutes (fa-2): Trainice #3C100 (manufactured by Toshikukiki, product model name, polymide resin, solid content 23%), drying at 230°C for 30 minutes (a-3): Br3170 (Mitsubishi Gas) Chemistry (..., trade name, bismaleimide resin) 90 parts/Epon 1009 (manufactured by Yuka Shell Co., Ltd., trade name, epoxy resin)
10 parts/2MZ (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name, 2-methylimidazole) 02 parts/cellosolve acetate 80
/20 parts of N-methyl-2-pyrrolidone, dried at 200°C for 30 minutes (a-4): 4,4-bismaleimidiphenylmethane was mixed with Epon 1007 (manufactured by Yuka Shell Co., Ltd., trade name, epoxy resin 4 resin). 80 parts of imide epoxy resin obtained by the reaction / 20 parts of Takenate B-800 (manufactured by Gakoku Yakuhin ((1), trade name, block isocyanate) / 80 parts of methylcarpitol / 10 parts of ethyl acetate, 200°C x 20
Dry for minutes (a-51: K Y N A R# 500 (Pen
NWALT Co., trade name, vinylidene fluoride resin) 70 parts / acrylic resin (copolymer of methyl methacrylate and isobutyl methacrylate) 30 parts / carpitol acetate 30 parts / isophorone 100 parts, dried at 210°C for 20 minutes / (a -6): Epon 828 (manufactured by Yuka Shell Co., Ltd., trade name, epoxy equivalent weight 190) 100 parts/2MZ (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name, 2-methylimidazole) 3 parts/xylene 100 parts, 180°C -20 Dry for minutes (a-7 acrylic resin (styrene/methyl methacrylate/n-butyl acrylate/2-ethylhexyl acrylate/lauryl methacrylate/hydroxyethyl nucleate, 08 value 60) 100 parts/knee pan 2
0SE (manufactured by Mitsui Toatsu Co., Ltd., trade name, melamine resin) 40
parts/100 parts of xylene, dried at 180°C for 20 minutes (2) Composition for adhesive (b) Mixed and dispersed with the composition and amount (parts) shown in Table 1,
A pressure-sensitive adhesive composition was produced.

(Mura) Epon 1004 (manufactured by Yuka Shell Co., Ltd., trade name, Tg
Point approx. 59℃, epoxy equivalent 925) (*2) Acrylic resin (styrene/n-butyl acrylate/n-butyl methacrylate/stearyl methacrylate/methyl methacrylate/2-ethyl hydroxy methacrylate/acrylic acid, Tg point -16℃ 1OH value 80) (Touge) Polyester resin (trimethylolpropane/1,6-hexanediol/isophthalic acid/hexamethylene diisocyanate, Tg point 0・℃ or less, 08 valence 8
0) (*4) Blocked isocyanate (methyl ethyl ketoxime blocking agent, hexamethylene diisocyanate, NCoa degree 8.7%) Examples and comparative examples A film was attached to an adherend in the following order.

(1) Apply adhesive compositions (b-1) to (b-g) on the films (a-1) to (a-7) using a doctor blade until the dry film thickness is 5 to 20 μm. Paint it like this.

(2) Dry at 100°C for 20 minutes.

(3) Paste release paper (Shikoku Paper, 100100X100).

(4) Cut with a cutter to 50xlOOmm.

(5) Peel off the release paper on the adhesive layer.

(6) Steel plate (SPCC-3B, 100100X150
Attach the film (5) to X1 by hand.

(7) Peel off the release paper.

(8) Bake at 200°C for 20 minutes.

The results are summarized in Table-2.

(*5) Film tackiness: The adhesive layer surface of the film subjected to the above-mentioned pasting film forming steps (1) to (5) is pasted onto a member (aluminum casting).

The degree of tackiness of the adhesive layer surface was examined.

(0) The adhesive layer has adhesive properties and can be easily attached to a member.

(△) The adhesive layer surface has low tackiness and easily peels off even when attached to a member.

(x) The adhesive layer has no tackiness at all and easily peels off even if pasted.

(*6) Finish: Visually inspect the appearance of the film.

(○) Good smoothness, especially no defects such as discoloration, shrinkage, or wrinkles on the surface.

(*7) Hardness: Evaluated according to JIS K5400 6.14 (medium 8) Adhesiveness: Use a knife to make 100 squares with a spacing of 2+ nm that reach the adherend (steel plate). Then apply cellophane tape, press firmly, and peel off.

(○) Does not peel off at all.

(Δ) 10 to 20 squares peel off.

(X) 50 or more squares come off.

(*9) Heat Resistance: Adhesion to the adherend was examined by strongly pulling the film while keeping it at 0°C.

(0) No peeling at all.

(△) It peels off easily or the film softens easily.

(x) Easily peeled off or the film softened and deformed.

Claims (1)

[Claims] 1. Polyimide-based, bismaleimide-based, polyamide-imide-based, polyimide-epoxy-based, polyamide-based, polysiloxane-based, polyoxadiazole-based, polypenzimidazole-based, triazine-based, polyvinyl fluoride-based, polyfluorinated A curable resin (with a glass transition point of 5°C or less) is coated on one side of a synthetic resin film of at least one type selected from vinylidene chloride, which has a glass transition point of 50°C or more and an elongation rate of 3% or more.
An adhesive film comprising a pressure-sensitive adhesive containing A) and a curing agent (B) having different curability as essential components. 2. Apply the adhesive according to claim 1 to one side of a synthetic resin film, cure the adhesive until the tack value falls within the range of 1 to 8, and then apply the adhesive layer side to the surface of the adherend. A film forming method characterized by interviewing and bonding under pressure, followed by heating.