JPH10306267A - Autohesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an autohesive sheet having excellent autohesivity, exhibiting excellent initial adhesivity even under the low-temperature environment, hard to be peeled off even after left to stand under the high-temperature environment for a long period, and high in durability. SOLUTION: This autohesive sheet is obtained by coating the release surface of a film base having a releasable surface with a photopolymerizable composition comprising the components (a) to (e) described below followed by photopolymerization of the composition; wherein the gel fraction of the partially crosslinked polymer in the adhesive layer of this sheet is 5-60 wt.%, the weight- average molecular weight of the sol portion is 50,000-70,000, and the glass transition temperature of the polymer is -10 to 30 deg.C. (a): 60-100 pts.wt. of a 2-18C alkyl (meth)acrylate, (b): 0-40 pts.wt. of an unsaturated double bond-bearing vinyl monomer copolymerizable with the component (a), (c): 0.01-5 pts.wt. of a photopolymerization initiator, (d): 0.01-2 pts.wt. of a polyfunctional vinyl compound having two or more unsaturated double bonds in one molecule, and (e): 0.05-2 pts.wt. of a radical chain transfer agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-adhesive sheet suitable mainly for binding and the like.

[0002]

2. Description of the Related Art Conventionally, a pressure-sensitive adhesive sheet or pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer provided on both sides of a flexible film substrate for binding or fixing various members (hereinafter simply referred to as "binding"). (Hereinafter simply referred to as "adhesive sheet")
However, it is widely used due to its simple joining property.
Such a binding adhesive sheet is required to have excellent adhesiveness between the adhesive layers (hereinafter, referred to as “self-adhesiveness”) and a property of not easily peeling even in a high temperature environment or a low temperature environment. Have been.

As an example of the above-mentioned adhesive sheet for binding, Japanese Patent Application Laid-Open No. Sho 58-149269 discloses that various articles such as vegetables, electronic parts, and building materials comprising a support and a self-adhesive polymer layer provided thereon are provided. In the self-adhesive tape for binding and fixing, the self-adhesive polymer layer is formed of an alkyl (meth) acrylate in the presence of a mixture of 20 to 80% by weight of neoprene rubber and 80 to 20% by weight of a butyl rubber. It contains a modified rubber obtained by subjecting at least one selected from esters, (meth) acrylonitrile and styrene-based unsaturated monomers to a radical polymerization reaction at a ratio of 10 to 100 parts by weight based on 100 parts by weight of the mixture. A self-adhesive tape for binding and fixing, characterized in that

[0004] As another example, Japanese Patent Application Laid-Open No. 61-1386 is disclosed.
Japanese Patent Publication No. 84, "On one surface of the tape base, for example,
20 to 40 parts by weight of factice and 30 parts by weight of a tackifying resin per 100 parts by weight of an elastomer containing a styrene-isoprene-styrene type block copolymer and natural rubber
A self-adhesive pressure-sensitive adhesive layer containing not more than parts by weight is provided, and on the other surface, a thermoplastic resin such as an ethylene-vinyl acetate copolymer, an acrylate ester copolymer or a vinyl chloride-vinyl acetate copolymer is provided. An adhesive tape for binding comprising a non-adhesive layer comprising a resin-based film-forming agent "has been proposed.

[0005] However, the conventional self-adhesive sheet as proposed in the above proposal, when exposed to a high temperature, causes the self-adhesive polymer layer or the self-adhesive pressure-sensitive adhesive layer to cohesively break and soften, thereby causing various kinds of binding objects to be bound. There is a problem of contaminating articles. Further, the self-adhesive polymer or self-adhesive pressure-sensitive adhesive containing a diene-based polymer also has a problem that it has poor long-term weather resistance.

[0006] As one method for solving the above problems,
A method of cross-linking a self-adhesive polymer or a self-adhesive pressure-sensitive adhesive is mentioned, but the self-adhesive sheet produced by this method is
There is a problem that the recovery force (repulsion force) of the film base material causes the peeling gradually from the end. Another method is to raise the glass transition temperature of the self-adhesive polymer or self-adhesive pressure-sensitive adhesive. However, the self-adhesive sheet produced by this method can be used at low temperatures such as in winter or in cold regions. When used in an environment, there is a problem that the initial adhesiveness is lacking.

As described above, a self-adhesive sheet that has excellent initial adhesiveness even in a low-temperature environment and does not easily peel off even in a high-temperature environment has not been put to practical use at present.

[0008]

SUMMARY OF THE INVENTION The present invention has excellent self-adhesiveness and solves the above-mentioned problems.
An object of the present invention is to provide a self-adhesive sheet which exhibits excellent initial adhesiveness even in a low-temperature environment, does not easily peel off even when left for a long time in a high-temperature environment, and has excellent durability.

[0009]

The self-adhesive sheet according to the invention of claim 1 (hereinafter referred to as "first invention") is a photopolymerizable composition containing the following components (a) to (e). A self-adhesive sheet obtained by applying the adhesive composition to a release surface of a film substrate having a releasable surface and photopolymerizing the gel composition of the partially crosslinked polymer of the adhesive layer of the self-adhesive sheet. Rate 5
-60% by weight, and the weight average molecular weight of the sol is 500
And the glass transition temperature is-
It is characterized by a temperature of 10 ° C to + 30 ° C. (A) Component: an alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms (b) Component: a vinyl monomer having an unsaturated double bond copolymerizable with the component (a) (c) component: Photopolymerization initiator (d) component: a polyfunctional vinyl compound having two or more unsaturated double bonds in one molecule (e) component: radical chain transfer agent

The self-adhesive sheet according to the invention of claim 2 (hereinafter referred to as “second invention”) is the self-adhesive sheet according to the first invention, wherein the photopolymerizable composition comprises (a) 60 to 100 parts by weight of component, (b) 0 to 40 parts by weight of component,
0.01 to 5 parts by weight of component (c), 0.01 to 5 parts by weight of component (d)
2 parts by weight, 0.005 to 2 parts by weight of component (e), and
The component (f) has a weight average molecular weight of 2,000 to 3,000.
0 to 1 to 50 parts by weight of an ethylene-butylene-based macromer.

Further, the self-adhesive sheet according to the invention of claim 3 (hereinafter referred to as "third invention") is the self-adhesive sheet according to the first or second invention, wherein component (b) is N -Is characterized by being vinylpyrrolidone.

The alkyl (meth) acrylate in which the alkyl group contained as the component (a) in the photopolymerizable composition used in the self-adhesive sheet according to the first invention has 2 to 18, preferably 4 to 14 carbon atoms. Is not particularly limited, for example, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, pentyl (amyl) (meth) acrylate,
Hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Isooctyl (meth) acrylate, isononyl (meth) acrylate, isomyristyl (meth) acrylate, isostearyl (meth) acrylate, octadecyl (meth) acrylate, and the like are preferably used. Here, “(meth) acrylate” means “acrylate” or “methacrylate”.

The above alkyl (meth) acrylate having 2 to 18 carbon atoms in the alkyl group may be used alone or in combination of two or more, but the adhesive layer of the resulting self-adhesive sheet may be used. In order to suitably maintain the balance between the tackiness and the cohesive force of the polymer, it is preferable to use an alkyl (meth) acrylate having a glass transition temperature of the homopolymer of 0 ° C. or lower.

The vinyl monomer having an unsaturated double bond copolymerizable with the component (a) contained as the component (b) in the photopolymerizable composition is not particularly limited. , N-vinylpyrrolidone, (meth) acrylonitrile, (meth) acrylamide, acryloylmorpholine, vinylpyridine, polycaprolactone mono (meth) acrylate, polyalkylene glycol mono (meth) acrylate, etc., and are preferably used.

The vinyl monomers having an unsaturated double bond may be used alone or in combination of two or more.

The vinyl monomer having an unsaturated double bond is, for example, a compound having a functional group weaker than the carboxyl group of a weak acid such as acrylic acid or methacrylic acid, or a secondary ammonium group. It is also preferable that the monomer be a low- or medium-polarity monomer such as a compound having a weakly basic functional group.

The heat resistance and self-adhesion rate of the adhesive layer of the self-adhesive sheet obtained by copolymerizing the vinyl monomer having an unsaturated double bond with the alkyl (meth) acrylate as the component (a). (Interdiffusion speed) and the like can be adjusted widely.

The photopolymerization initiator contained as the component (c) in the photopolymerizable composition is not particularly limited, but, for example, trade name “Irgacure 184” (manufactured by Ciba Geigy), trade name “Irgacure 651” (manufactured by Ciba-Geigy), 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone (for example, trade name “Darocure 2959”, manufactured by Merck),
Ketone-based photopolymerization initiators such as halogenated ketones; α-hydroxy-α, α′-dimethylacetophenone (for example,
Acetophenone-based photopolymerization initiators such as "Darocur 1173" (trade name, manufactured by Merck), methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone;
Benzoin ether photopolymerization initiators such as benzoin ethyl ether and benzoin isopropyl ether; ketal photopolymerization initiators such as benzyl dimethyl ketal; phosphorous-containing photopolymerization initiators such as acylphosphinoxide and acylphosphonate. Are preferably used.

The above photopolymerization initiators may be used alone or in combination of two or more.

A polyfunctional vinyl compound having two or more unsaturated double bonds in one molecule contained as the component (d) in the photopolymerizable composition (hereinafter simply referred to as "polyfunctional vinyl compound") ) Are not particularly limited, but include, for example, hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di). (Meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epo Shi acrylate, polyester acrylate, urethane acrylate and the like,
It is preferably used.

The above polyfunctional vinyl compounds may be used alone or in combination of two or more.

The above-mentioned polyfunctional vinyl compound has a function as a crosslinking agent and improves the heat resistance of the adhesive layer of the obtained self-adhesive sheet. However, since excessive crosslinking impairs the self-adhesiveness of the self-adhesive sheet, it is preferable to include it in such an amount that the degree of crosslinking falls within an appropriate range.

The radical chain transfer agent contained as the component (e) in the photopolymerizable composition is not particularly limited. For example, a compound having a mercapto group such as lauryl mercaptan in the molecule or a disulfide Group,
Compounds having a halogen group, a phenol group, a compound having a conjugated double bond group, or a compound having a functional group that causes a chain transfer reaction in a radical growth reaction of a vinyl group such as alpha methylstyrene dimer, and the like are preferably used. .

The above radical chain transfer agents may be used alone or in combination of two or more.

In the self-adhesive sheet according to the first invention, the photopolymerizable composition containing the above-mentioned components (a) to (e) is applied to the release surface of a film substrate having a release surface. The self-adhesive sheet has a gel fraction of 5 to 60% by weight, preferably 10 to 40% by weight, and a weight average molecular weight of the sol. 50,000 to 700,000, and a glass transition temperature of -10 ° C to + 30 ° C.

If the gel fraction of the partially crosslinked polymer in the adhesive layer is less than 5% by weight, the cohesive force at high temperatures becomes insufficient, causing a cold flow and sticking the side of the self-adhesive sheet. If it exceeds 60% by weight, on the other hand, if it exceeds 60% by weight, the time required for self-adhesion due to interdiffusion is prolonged. Even if the adhesive layers are adhered to each other, peeling may occur due to internal stress of the self-adhesive sheet. There is.

The gel fraction of the partially crosslinked polymer in the adhesive layer is determined by properly selecting the type and amount of the polyfunctional vinyl compound (crosslinking agent) as the component (d), and setting the degree of crosslinking within an appropriate range. Can be adjusted.

If the weight average molecular weight of the sol component of the adhesive layer is less than 50,000, the self-adhesive sheet may become sticky due to poor cohesive strength, and conversely 700
If it exceeds 000, the time until mutual diffusion and self-adhesion may be too long.

The weight average molecular weight of the sol component of the adhesive layer is as follows:
It can be adjusted by appropriately selecting the type and amount of the above-mentioned polyfunctional vinyl compound (crosslinking agent) as the component (d) and the radical chain transfer agent as the component (e), and by combining them.

Further, the glass transition temperature of the adhesive layer is-
When the temperature is lower than 10 ° C., the cohesive strength is poor, and the self-adhesive sheet may be sticky. On the contrary, when the temperature exceeds + 30 ° C., the self-adhesiveness may be poor.

The self-adhesive sheet according to the second aspect of the present invention is the self-adhesive sheet according to the first aspect, wherein the photopolymerizable composition comprises 60 to 100 parts by weight of the component (a) and 0 to 100 parts by weight of the component (b). 40 parts by weight, 0.01 to 5 parts by weight of component (c),
0.01 to 2 parts by weight of component (d), 0.005 of component (e)
To 2 parts by weight, and 1 to 50 parts by weight of an ethylene-butylene-based macromer having a weight average molecular weight of 2,000 to 30,000 described later as the component (f).

The content of the alkyl (meth) acrylate having 2 to 18 carbon atoms in the alkyl group as the component (a) is less than 60 parts by weight, or the component (a) as the component (b) When the content of the vinyl monomer having an unsaturated double bond copolymerizable with the above exceeds 40 parts by weight, the cohesive strength and heat resistance of the obtained self-adhesive sheet and the self-adhesion and self-adhesion speed Improper balance may result.

When the content of the photopolymerization initiator as the component (c) is less than 0.01 part by weight, photopolymerization may not be sufficiently caused. Conversely, when the content exceeds 5 parts by weight, The weight average molecular weight of the polymer obtained by photopolymerization becomes small, and the cohesive force, heat resistance, and the like of the self-adhesive sheet may become poor.

Furthermore, when the content of the polyfunctional vinyl compound (crosslinking agent) having two or more unsaturated double bonds in one molecule as the component (d) is less than 0.01 part by weight,
Necessary and sufficient cross-linking may not occur. Conversely, if it exceeds 2 parts by weight, cross-linking becomes excessive and the self-adhesiveness of the self-adhesive sheet may be poor.

Further, the content of the radical chain transfer agent as the component (e) is less than 0.005 parts by weight,
When the amount exceeds 2 parts by weight, chain transfer becomes insufficient or excessive, and it may be difficult to adjust the weight average molecular weight of the obtained polymer to an appropriate range.

The photopolymerizable composition used for the self-adhesive sheet according to the second invention has a weight average molecular weight of (f) component based on 100 parts by weight of the total of the above components (a) and (b). Contains 1 to 50 parts by weight of an ethylene-butylene-based macromer having a molecular weight of 2,000 to 30,000.

The above-mentioned ethylene-butylene macromer is a product obtained by grafting a compound having an acrylate group at the hydroxyl group portion, using an ethylene-butylene oligomer having a hydroxyl group at one end synthesized by anionic polymerization as a main raw material. is there.

Specific examples of the ethylene-butylene-based macromer are not particularly limited. For example, the trade name is “KRATON LIQUID Polym”.
erHPVM-1251 "(Shell Chemical
al.) and "KLP L-1203" (manufactured by Yuka Shell Co., Ltd.) and the like, and are preferably used.

The above ethylene-butylene macromer is
They may be used alone or in combination of two or more.

By including the ethylene-butylene macromer in the photopolymerizable composition, the adhesion to so-called poorly adherent adherends such as polyolefin, Teflon, silicone, and inorganic members having uneven surfaces was remarkably improved. A self-adhesive sheet can be obtained.

If the weight average molecular weight of the above ethylene-butylene macromer is less than 2,000, the cohesive strength of the polymer obtained by photopolymerization becomes poor, and the self-adhesive sheet may become sticky, and conversely, 30,000 If it exceeds, the polymer becomes hard and the self-adhesiveness of the self-adhesive sheet may be poor.

When the content of the ethylene-butylene-based macromer is less than 1 part by weight based on 100 parts by weight of the total of the components (a) and (b), self-adhesion to the poorly adherent adherend is achieved. In some cases, the adhesiveness of the self-adhesive sheet may not be sufficiently improved. On the other hand, when the amount exceeds 50 parts by weight, the polymer obtained by photopolymerization may be hard and the self-adhesiveness of the self-adhesive sheet may be poor.

The self-adhesive sheet according to the third invention is the self-adhesive sheet according to the first or second invention described above,
It is necessary that the vinyl monomer having an unsaturated double bond copolymerizable with the component (a), which is the component (b), is N-vinylpyrrolidone.

By using N-vinylpyrrolidone as the component (b), it is possible to obtain a self-adhesive sheet which is more excellent in self-adhesiveness, initial adhesiveness in a low-temperature environment, durability in a high-temperature environment, and the like. .

The photopolymerizable composition used in the self-adhesive sheets according to the first to third inventions may contain, if necessary, the above-mentioned (a) which is an essential component within a range that does not hinder the achievement of the object of the present invention. Component to component (e) (first invention or third invention)
Or one or more of various additives such as a tackifying resin, a thickening agent, a thixotropic agent, a bulking agent, and a filler, in addition to the components (a) to (f) (the second or third invention). May be contained.

The tackifying resin is not particularly restricted but includes, for example, rosin resin, hydrogenated rosin resin, rosin ester resin, hydrogenated rosin ester resin, disproportionated rosin resin, disproportionated rosin ester Rosin or modified rosin resins such as resins, polymerized rosin resins and polymerized rosin ester resins; terpene resins such as terpene resins and hydrogenated terpene resins; terpene phenolic resins such as terpene phenolic resins and hydrogenated terpene phenolic resins;
Petroleum resins such as quinone (aliphatic) petroleum resin and C9 (aromatic) petroleum resin; and coumarone indene resins such as coumarone indene resin and hydrogenated coumarone indene resin. Among them, a tackifier resin having less unsaturated bonds is more preferably used.

The above tackifier resins may be used alone or in combination of two or more.

The thickener is not particularly limited, and examples thereof include acrylic rubber, epichlorohydrin rubber, isoprene rubber and butyl rubber, and are preferably used. The thickeners may be used alone or in combination of two or more.

The thixotropic agent is not particularly restricted but includes, for example, colloidal silica and polyvinylpyrrolidone, which are preferably used.
The thixotropic agent may be used alone,
Two or more types may be used in combination.

The extender is not particularly restricted but includes, for example, calcium carbonate, clay, talc, titanium oxide and the like, and is preferably used. The extender may be used alone or in combination of two or more.

The filler is not particularly limited, but includes, for example, inorganic hollow bodies such as glass balloons, alumina balloons and ceramic balloons; and organic spherical bodies such as nylon beads, acrylic beads, silicone beads and polyethylene beads. Organic hollow bodies such as vinylidene chloride balloons and acrylic balloons; monofilaments such as polyester, rayon and nylon; and the like are preferably used.

The above fillers may be used alone or in combination of two or more.

The method for preparing the photopolymerizable composition used for the self-adhesive sheet according to the first to third inventions is not particularly limited, and may be a conventional mixer such as a universal mixer, a planetarium mixer, a Banbury mixer, a kneader, or a roll. Using a mixing device at room temperature or under heating, the essential components (a) to (e) (first invention or third invention)
Alternatively, a composition consisting of component (a) to component (f) (second invention or third invention) and one or more of various additives to be contained as needed is uniformly stirred and mixed. What is necessary is just to obtain a desired photopolymerizable composition.

The self-adhesive sheets according to the first to third inventions are prepared by applying the above-prepared photopolymerizable composition to a release surface of a film substrate having a release surface and irradiating the film with light. It is produced by causing a photopolymerization reaction and photopolymerizing the photopolymerizable composition.

The film substrate having the releasable surface is not particularly limited, and examples thereof include paper, polyethylene terephthalate (PET) film, polyethylene film, Teflon film, and polyimide film. Can be

The method for applying the photopolymerizable composition to the release surface of the film substrate is not particularly limited, and may be a conventional method such as a roll coater, a comma coater, a knife coater, a gravure coater, a curtain coater, a lip coater, and a die coater. What is necessary is just to carry out by a general solution coating system using a coating device.

The coating thickness of the photopolymerizable composition is not particularly limited, but is preferably 100 to 5000 μm in consideration of the product thickness of the self-adhesive sheet almost as it is.

Further, at the time of manufacturing the self-adhesive sheet, a core material may be used to impart a reinforcing effect and a thickness to the self-adhesive sheet.

The core material is not particularly limited, but nonwoven fabric, glass sheet, glass mat, trade name “Sof” (manufactured by Sekisui Chemical Co., Ltd.) and the like are preferably used. The above core material may be used alone, or two or more kinds may be used in combination.

When the above core material is used, the photopolymerizable composition is applied to the release surface of the film substrate, the core material is laminated thereon, and the photopolymerizable composition is further applied thereon. Irradiation may be carried out to photopolymerize the photopolymerizable composition to produce a self-adhesive sheet at once, or the steps may be divided to produce a self-adhesive sheet stepwise.

The type of lamp used for light irradiation for photopolymerizing the photopolymerizable composition includes a light wavelength of 400 n.
m is used, and is not particularly limited. Examples thereof include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide. Lamps and the like are mentioned, and are preferably used,
Above all, while efficiently emitting light in the active wavelength region of the photopolymerization initiator, and heating and evaporating short-wavelength light or a photopolymerizable composition that reduces the viscoelastic properties of the obtained polymer by crosslinking. A chemical lamp that does not emit much long-wavelength light is more preferably used.

The light irradiation intensity at the time of the light irradiation is a main factor affecting the degree of polymerization of the obtained polymer, and may be appropriately set according to the performance to be achieved by the target product.
For example, when a conventional cleavage type photopolymerization initiator having an acetophenone group is used, a wavelength region that is effective for photodecomposition of the photopolymerization initiator and does not involve light absorption by other composition components ( Irradiation intensity is usually 0.1 to 365 (420 to 420 nm) depending on the type of photopolymerization initiator.
Preferably, it is 〜100 mW / cm ² .

In the photopolymerization performed in the production of the self-adhesive sheet according to the present invention, the photopolymerization reaction may be inhibited by oxygen in the air or dissolved oxygen in the photopolymerizable composition. Light irradiation is preferably performed by a process technique capable of preventing reaction inhibition.

The process method capable of preventing the above-described reaction inhibition by oxygen is not particularly limited.
For example, a method of covering the photopolymerizable composition with a transparent film such as a PET film or a Teflon film to block air, irradiating the photopolymerizable composition with light through the transparent film to perform photopolymerization, Gas, air is replaced by an inert gas such as carbon dioxide, and a method of performing photopolymerization in an inert zone having a light-transmissive window, and the like,
Either is suitably adopted.

In the above method, when the inert zone is used, in order to sufficiently complete the polymerization of the photopolymerizable composition until the conversion is 99.7% or more, the oxygen concentration in the inert zone is 5000 ppm or less. It is preferred that

The weight average molecular weight of the polymer obtained by photopolymerizing the photopolymerizable composition decreases as the oxygen concentration in the atmosphere increases. Therefore, in order to obtain a polymer having the same weight average molecular weight as when photopolymerization is performed in a completely inert atmosphere, the oxygen concentration in the inert zone is more preferably 1000 ppm or less.

Since the surface layer of the photopolymerizable composition is more susceptible to reaction inhibition by oxygen than the inner layer, it is necessary to make the cohesive force of the surface layer of the obtained polymer equal to that of the inner layer. Means that the oxygen concentration in the inert zone is 3
More preferably, it is not more than 00 ppm.

[0068]

The self-adhesive sheet according to the first invention comprises the component (a)
(E) The photopolymerizable composition containing the component is obtained by photopolymerization, and the gel fraction, the weight average molecular weight and the glass transition temperature of the sol component of the partially crosslinked polymer of the adhesive layer are each specified. As it is set to be within the range, it excels in self-adhesiveness, exhibits excellent initial adhesion even in a low temperature environment, and does not easily peel off even if left for a long time in a high temperature environment, durable Excellent in nature.

The self-adhesive sheet according to the second invention is the self-adhesive sheet according to the first invention, wherein the photopolymerizable composition contains a specific amount of the components (a) to (e); Furthermore, since it contains a specific amount of the component (f), it exhibits more excellent self-adhesiveness, initial adhesiveness in a low-temperature environment, durability in a high-temperature environment, and the like, and adhesion to a poorly adherent adherend. Also excellent in nature.

Further, the self-adhesive sheet according to the third aspect of the present invention
In the self-adhesive sheet according to the first invention or the second invention, since N-vinylpyrrolidone is used as the component (b), more excellent self-adhesion, initial adhesion in a low-temperature environment,
In addition to exhibiting durability in a high-temperature environment, it also has excellent adhesion to hardly adherent adherends.

[0071]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight”, and “%” means “% by weight” unless otherwise specified.

(Example 1)

(1) Preparation of photopolymerizable composition In a separable flask, 60 parts of 2-ethylhexyl acrylate as the component (a), 40 parts of N-vinylpyrrolidone as the component (b), and trade name as the component (c) 0.1 part of "Irgacure 184" (manufactured by Ciba Geigy)
Hexanediol diacrylate 0.
And 0.5 parts of lauryl mercaptan as component (e).
After adding 0.05 parts and uniformly stirring and mixing, 3 parts of nitrogen gas were added.
Purging was performed for 0 minute to remove dissolved oxygen in the system, thereby preparing a photopolymerizable composition.

(2) Preparation of Self- Adhesive Sheet A polyethylene terephthalate (PET) film having a releasable surface in which the photopolymerizable composition obtained above was adhered to a cooled stainless steel plate maintained at 10 ° C. (Thickness: 38 μm) The coating thickness is 500 μm on the release surface of the substrate.
And a peeled surface of a PET film (38 μm thick) having a peelable surface was laminated on the coated surface. Next, a chemical lamp having a length of 600 mm and 40 W was used as an ultraviolet light source, and the height of the chemical lamp was set so that the light intensity of the irradiation surface was ² mW / cm ^2. UV light for 5 minutes through the photopolymerizable composition to perform photopolymerization.
The ET film substrate was peeled off to obtain a self-adhesive sheet having a non-adhesive surface. Note that the light intensity is a wavelength of 365 n.
light intensity measuring instrument (model “UVR-
1 ", Tokyo Optical Machine Co., Ltd.).

(3) Evaluation The performance (gel fraction, weight average molecular weight, glass transition temperature, and electric wire binding property) of the self-adhesive sheet obtained above was evaluated by the following methods. The results were as shown in Table 1. The evaluation was 23 unless otherwise stated.
The test was performed in an atmosphere at a temperature of -65% RH.

Gel Fraction 100 g of a sample collected from the self-adhesive sheet was dissolved in 50 cc of tetrahydrofuran (THF), and the solution was melted at 23 ° C.-65.
It was left for 24 hours in an atmosphere of% RH. Next, the obtained swollen gel solution was filtered through a 200-mesh stainless steel membrane, and the dry weight of the filtered residue was measured, and the ratio to the sample weight was calculated to determine the gel fraction (%).

Weight average molecular weight The eluted sol content obtained during the evaluation of the above gel fraction was determined to be 0.1% .
The solution was filtered through a Teflon filter having a pore size of 4 μm to obtain a filtrate. Next, GPC (gel permeation chromatography) measurement of the obtained filtrate was performed, and the weight average molecular weight was calculated as a so-called polystyrene equivalent molecular weight calculated from an elution time and a molecular weight calibration curve prepared using standard polystyrene.

Glass transition temperature The peak temperature of tan δ at a vibration frequency of 10 Hz was determined by using a viscoelastic spectrometer, which was defined as the glass transition temperature (° C.).

The electric wire binding self-adhesive sheet is used to bind 10 electric wires, observe the state of adhesion between the self-adhesive sheet surfaces (initial self-adhesion), and forcibly peel off immediately after adhesion and three days after adhesion. And the peeled state was observed.

(Example 2) In the preparation of the photopolymerizable composition, the composition was as follows: 50 parts of 2-ethylhexyl acrylate as the component (a), 30 parts of N-vinylpyrrolidone as the component (b), and 30 parts as the component (c). "Irgacure 1
84 "0.1 part, hexanediol diacrylate 0.04 part as component (d), lauryl mercaptan 0.02 part as component (e), and trade name" KR "as component (f).
ATON LIQUID Polymer HPVM-
1251 "(manufactured by Shell Chemical) 10
Part and tackifying resin (trade name “Alcon P-120”,
A self-adhesive sheet was obtained in the same manner as in Example 1 except that 20 parts (manufactured by Arakawa Chemical Industry Co., Ltd.) were used.

Comparative Example 1 A self-adhesive sheet was obtained in the same manner as in Example 1 except that lauryl mercaptan as the component (e) was not contained in the preparation of the photopolymerizable composition.

The performance of the two types of self-adhesive sheets obtained in Example 2 and Comparative Example 1 was evaluated in the same manner as in Example 1.
The results were as shown in Table 1.

[0083]

[Table 1]

As shown in Table 1, the self-adhesive sheet of Example 1 or Example 2 according to the present invention exhibits excellent initial self-adhesiveness and is capable of being peeled off immediately after bonding. After a lapse of time (3 days after bonding), an excellent bonding state is exhibited.

On the other hand, the self-adhesive sheet of Comparative Example 1 in which the photopolymerizable composition did not contain the radical chain transfer agent (e) was a weight average of the gel fraction and the sol content of the partially crosslinked polymer. Since the molecular weight was too high, not only the initial self-adhesiveness was insufficient, but also spontaneous peeling after a lapse of time (3 days after bonding).

[0086]

As described above, the self-adhesive sheets according to the first to third aspects have excellent self-adhesiveness,
It exhibits excellent initial adhesiveness even in a low-temperature environment, and does not easily peel off even when left for a long time in a high-temperature environment, and is excellent in durability. Therefore, it is suitable for use in binding or fixing various members. Can be

For example, when used for binding a wire harness of an automobile, the self-adhesive sheet cold-flows to fill not only the gaps of the bundled wire harnesses but also the wiring holes in the vehicle. As a result, a high sealing effect is exhibited, and after filling to a certain extent, the cold flow is stopped by the cohesive force due to crosslinking, so that no gap is formed in the wiring hole after a long time.

When the self-adhesive sheets according to the first to third aspects of the present invention are adhered to the surface of a hard-to-adhesive inorganic building material having an uneven surface, the sheet naturally adheres to the uneven surface. Finally, since it exhibits excellent adhesiveness, it is suitably used as an adhesive or a sealing agent.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 139/06 C09J 139/06

Claims (3)

[Claims] 1. A self-curable composition obtained by applying a photopolymerizable composition containing the following components (a) to (e) to a release surface of a film substrate having a releasable surface and photopolymerizing the composition. An adhesive sheet, wherein the gel fraction of the partially crosslinked polymer of the adhesive layer of the self-adhesive sheet is 5 to 60% by weight, the weight average molecular weight of the sol is 50,000 to 700,000, and
A self-adhesive sheet having a glass transition temperature of −10 ° C. to + 30 ° C. (A) Component: an alkyl (meth) acrylate having an alkyl group having 2 to 18 carbon atoms (b) Component: a vinyl monomer having an unsaturated double bond copolymerizable with the component (a) (c) component: Photopolymerization initiator (d) component: a polyfunctional vinyl compound having two or more unsaturated double bonds in one molecule (e) component: radical chain transfer agent 2. The photopolymerizable composition according to claim 1, wherein the component (a)
To 100 parts by weight, component (b) 0 to 40 parts by weight, component (c) 0.01 to 5 parts by weight, component (d) 0.01 to 2 parts by weight, component (e) 0.005 to 2 parts by weight And (f)
2. The self-adhesive sheet according to claim 1, comprising 1 to 50 parts by weight of an ethylene-butylene macromer having a weight average molecular weight of 2,000 to 30,000 as a component. 3. The self-adhesive sheet according to claim 1, wherein the component (b) is N-vinylpyrrolidone.