JP2002356666A - Photoreactive hot-melt adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreactive, hot-melt adhesive composition that cures rapidly by light irradiation, and shows, after curing, excellent initial adhesion strength and excellent high-temperature adhesion strength when applied to wide kinds of adherends, that has excellent storing stability, and that does not give undesirable influence on working circumstances. SOLUTION: This photoreactive hot-melt adhesive composition comprises a cationically polymerizable compound A that is solid at an ordinary temperature, and has not less than one cationically polymerizable groups on average represented by the specific general formula (1) in a molecule, a cationically polymerizable compound B represented by specific general formula (2) or a cationically polymerizable compound C represented by the specific general formula (3), and a photocationic polymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo-reactive hot-melt type adhesive composition which is applied by heat-melt coating and is cured by light irradiation.

[0002]

2. Description of the Related Art A hot-melt type adhesive has an advantage that it exhibits a high adhesive force and is advantageous in terms of safety and hygiene because it is a solventless type. , Light electricity, transportation and other fields,
It is widely used for bonding various adherends such as paper, fiber, wood, plastic, metal and glass.

[0003] The hot-melt type adhesive is usually used in an applicator for hot-melt for 100 to 100 hours.
It is heated and melted at a temperature of about 200 ° C., and is applied to the adherend in a molten state. The melt-coated hot melt adhesive adheres to the adherend by cooling and solidifying. Such a hot-melt type adhesive has the advantage that the time from bonding the adherends to the development of the bonding strength is very fast, usually within 1 minute, and the bonding operation can be performed in a very short time. Having.

[0004] However, hot-melt type adhesives have a problem that they need to be melted by heating and are therefore composed of a thermoplastic component, and generally have insufficient heat resistance. Therefore, when applying or laminating hot melt type adhesive, by introducing a curing system by some kind of chemical reaction,
Studies for improving heat resistance have been widely conducted.

As a hot-melt adhesive incorporating the above curing system, for example, JP-A-49-98445 discloses urethane prepolymer, ethylene-vinyl acetate copolymer, abietic acid type rosin derivative and terpene-type rosin. A moisture-reactive (moisture-curable) hot-melt adhesive made of a phenolic copolymer resin is disclosed.

However, the moisture-reactive hot-melt type adhesive disclosed in the above-mentioned publication has a curing reaction that proceeds due to moisture (humidity) in the air or in an adherend, and therefore generally has a slow curing reaction. In particular, when the adherend is made of a moisture-impermeable material, the curing becomes insufficient or the curing takes a very long time, and the moisture-curing reaction proceeds at room temperature, so that the storage stability is low. There is a problem that it is hindered, and furthermore, since it contains an isocyanate compound (urethane prepolymer), it adversely affects the working environment.

On the other hand, as a curing system instead of a moisture reaction (moisture curing), curing of a cationically polymerizable compound such as an epoxy compound by using a photo-cationic polymerization initiator capable of decomposing by light to generate a Lewis acid. Investigations have been made on a curing system for achieving this.

For example, JP-B-3-30633 discloses a bisphenol type and / or novolak type epoxy compound, a liquid alicyclic epoxy compound having a viscosity of 500 centipoise or less, and a photocation which is an aromatic sulfonium salt of Lewis acid. An optical adhesive comprising a polymerization initiator as a main component and having a viscosity of 800 centipoise or less is disclosed.

However, the optical adhesive disclosed in the above publication is liquid at room temperature and is not of a hot-melt type, and thus does not have the above-mentioned advantages of a hot-melt type adhesive.

If a curing system using a cationically polymerizable compound such as an epoxy compound and a photo-cationic polymerization initiator is introduced into a hot-melt adhesive, a photoreactive (photo-curable) hot-melt adhesive can be obtained. By curing by irradiation with light, the heat resistance of the hot melt adhesive can be increased.

However, in a hot-melt type adhesive obtained by simply combining an epoxy compound and a photo-cationic polymerization initiator, internal distortion occurs in a cured product due to shrinkage during photo-curing,
There is a problem that the adhesiveness between the adherend and the adhesive is reduced, and sufficient adhesive strength cannot be obtained.

[0012]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the conventional hot-melt adhesive, the object of the present invention is to cure quickly by light irradiation, and to cure a wide range of adherends after curing. Another object of the present invention is to provide a photo-reactive hot-melt adhesive composition which exhibits excellent normal-state adhesive strength and excellent heat-resistant adhesive strength, has excellent storage stability, and does not adversely affect the working environment.

[0013]

According to the present invention, there is provided a photoreactive hot-melt adhesive composition according to the present invention, comprising a cationically polymerizable reactive group represented by the following general formula (1) in an average of 1 per molecule. It is characterized by comprising a cationic polymerizable compound A having a solid state at room temperature, a cationic polymerizable compound B represented by the following general formula (2), and a cationic photopolymerization initiator.

Embedded image (Wherein R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an isoamyl group or a phenyl group, and R ₅ , R ₆ and R ₇ represent a hydrogen atom or Represents an organic group, and k and m are 0, 1 or 2
Indicates)

Embedded image In the formula, R ₈ and R _{9 each} represent a hydrogen atom or a methyl group; R ₁₀ and R _{11 each} represent a cationically polymerizable reactive group represented by the above general formula (1); And n represents a positive integer of 1 or more.

The photoreactive hot-melt adhesive composition according to the second aspect of the present invention has an average of at least one cationically polymerizable reactive group represented by the following general formula (1) per molecule. And a solid cationic polymerizable compound A, a cationic polymerizable compound C represented by the following general formula (3), and a cationic photopolymerization initiator.

Embedded image (Wherein R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an isoamyl group or a phenyl group, and R ₅ , R ₆ and R ₇ represent a hydrogen atom or Represents an organic group, and k and m are 0, 1 or 2
Indicates)

Embedded image In the formula, R ₈ and R _{9 each} represent a hydrogen atom or a methyl group; R ₁₀ and R _{11 each} represent a cationically polymerizable reactive group represented by the above general formula (1); And n represents a positive integer of 1 or more.

Hereinafter, the present invention will be described in more detail. The cationic polymerizable compound A (hereinafter simply referred to as “cationic polymerizable compound A”) which is a solid at room temperature and has an average of one or more cationically polymerizable reactive groups represented by the above general formula (1) used in the present invention per molecule. ) Is not particularly limited, as long as it is a compound which has at least one cationically polymerizable reactive group represented by the general formula (1) in the molecule and is solid at ordinary temperature.

The cationically polymerizable compound A may have the cationically polymerizable reactive group represented by the general formula (1) in the molecular skeleton, at the terminal of the molecular skeleton, or as a side chain. May be. In addition, the cationic polymerizable compound A
May contain a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or the like as a constituent atom.

The structure, molecular weight and properties of the cationic polymerizable compound A are not particularly limited, either.
Any of an oligomer, a polymer and the like may be used.

Examples of the cationic polymerizable compound A include, but are not particularly limited to, an epoxy compound which is solid at room temperature, an oxetane compound which is solid at room temperature, and an oxolane compound which is solid at room temperature. Examples thereof include cyclic ether compounds that are solid at room temperature such as compounds, and among them, epoxy compounds that are solid at room temperature are preferably used because of their excellent cationic polymerization properties. These cationically polymerizable compounds A may be used alone or in combination of two or more.

Specific examples of the epoxy compound which is solid at room temperature include, but are not particularly limited to, a bisphenol A type epoxy resin which is solid at room temperature, a bisphenol F type epoxy resin which is solid at room temperature, and room temperature. And a solid novolak type epoxy resin. These epoxy compounds which are solid at room temperature may be used alone or in combination of two or more.

The cationically polymerizable compound B (hereinafter simply referred to as “cationically polymerizable compound B”) represented by the general formula (2) used in the present invention according to claim 1 is:
Having at least one alkylene oxide in the molecule, and
The cationically polymerizable reactive group represented by the general formula (1)
Any compound having an average of two or more molecules per molecule may be used, and is not particularly limited.

The cationically polymerizable compound B may have the cationically polymerizable reactive group represented by the general formula (1) in the molecular skeleton, at the terminal of the molecular skeleton, or as a side chain. May be. In addition, the cationic polymerizable compound B
May contain a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or the like as a constituent atom.

The structure, molecular weight and properties of the cationic polymerizable compound B are not particularly limited, either.
Any of an oligomer, a polymer and the like may be used.

The cationically polymerizable compound B is solid at room temperature, and may be a hot-melt resin itself, or may be a semi-solid or liquid at room temperature.

The cationic polymerizable compound B is not particularly limited, but examples thereof include cyclic ether compounds such as epoxy compounds, oxetane compounds, and oxolan compounds. Epoxy compounds are preferably used because of their excellent cationic polymerizability. These cationically polymerizable compounds B may be used alone or in combination of two or more.

Specific examples of the epoxy compound include:
Although not particularly limited, for example, diglycidyl compounds of polyoxyethylene, diglycidyl compounds of polyoxypropylene, diglycidyl compounds of isobutylene and diglycidyl compounds of neopentylene, diglycidyl compounds of alkylene having a branched chain, bisphenol A and bisphenol And a diglycidyl compound of a polyol in which F is added with ethylene oxide or propylene oxide. These epoxy compounds,
They may be used alone or in combination of two or more.

The cationically polymerizable compound C represented by the general formula (3) used in the present invention according to claim 2 (hereinafter simply referred to as “cationically polymerizable compound C”) is
Having at least one alkylene oxide in the molecule, and
The cationically polymerizable reactive group represented by the general formula (1)
A compound having an average of two or more compounds per molecule, wherein 2 in the general formula (2) of the “cationically polymerizable compound B”
Any aromatic ring may be used as long as it has a hydrogenated structure, and is not particularly limited.

The cationically polymerizable compound C may have the cationically polymerizable reactive group represented by the general formula (1) in the molecular skeleton, at the terminal of the molecular skeleton, or as a side chain. May be. The cationic polymerizable compound C
May contain a carbon atom, a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, or the like as a constituent atom.

The structure, molecular weight and properties of the cationic polymerizable compound C are not particularly limited, either.
Any of an oligomer, a polymer and the like may be used.

The cationically polymerizable compound C is solid at room temperature, and may be a hot-melt resin itself, or may be a semi-solid or liquid at room temperature.

Examples of the cationic polymerizable compound C include, but are not particularly limited to, cyclic ether compounds such as an epoxy compound, an oxetane compound, and an oxolane compound. Epoxy compounds are preferably used because of their excellent cationic polymerizability. These cationically polymerizable compounds C may be used alone or in combination of two or more.

Specific examples of the epoxy compound include:
Although not particularly limited, for example, diglycidyl compounds of polyoxyethylene, diglycidyl compounds of polyoxypropylene, diglycidyl compounds of isobutylene and diglycidyl compounds of neopentylene, diglycidyl compounds of alkylene having a branched chain, bisphenol A and bisphenol And a diglycidyl compound of a polyol in which F is added with ethylene oxide or propylene oxide. These epoxy compounds,
They may be used alone or in combination of two or more.

By using the cationically polymerizable compound A and the cationically polymerizable compound B or the cationically polymerizable compound C together, the photoreactive hot-melt adhesive composition of the present invention exhibits shrinkage during photocuring. The internal strain is absorbed and alleviated, and the adhesion to the adherend is improved, so that excellent adhesive strength can be exhibited.

The mixing ratio of the cationically polymerizable compound A to the cationically polymerizable compound B or the cationically polymerizable compound C is not particularly limited. Compound A
Is preferably 1/99 to 70/30.

When the ratio of the cationically polymerizable compound B or C / the cationically polymerizable compound A (by weight) is less than 1/99, the initial adhesive strength of the resulting photoreactive hot-melt adhesive composition to an adherend is low. On the contrary, if the cationic polymerizable compound B or C / cationic polymerizable compound A (weight ratio) exceeds 70/30, the photoreactive hot-melt adhesive composition irradiated with light may be insufficient. If the cohesive force immediately after bonding is insufficient, and if not held down or allowed to stand, displacement may occur in the bonded portion.

As the photocationic polymerization initiator used in the present invention, any one capable of generating a cation for initiating the polymerization of the cationically polymerizable compound A and the cationically polymerizable compound B or C by irradiation with light can be used. Although not particularly limited, examples thereof include an ionic photoacid generating type photocationic polymerization initiator. These cationic photopolymerization initiators may be used alone or in combination of two or more.

The ionic photoacid generating type photocationic polymerization initiator is not particularly limited, but examples thereof include an aromatic iodonium salt, an aromatic sulfonium salt, an aromatic diazonium salt and an aromatic halonium salt. Organic metal complexes such as onium salts, metallocene salts, arylsilanol / aluminum complexes, iron / allene complexes, titanocene complexes, and the like. These ionic photoacid generating type photocationic polymerization initiators may be used alone or in combination of two or more.

Specific examples of these cationic photopolymerization initiators include:
For example, aromatic iodonium salts and aromatic sulfonium salts are disclosed in US Pat. No. 4,256,828, and metallocene salts are disclosed in US Pat. No. 5,089,536.

The photoreactive hot-melt adhesive is incorporated into the photoreactive hot-melt adhesive composition, for example, by irradiating light having a wavelength of 200 to 600 nm. The composition can be rapidly cured, and can exhibit excellent normal state adhesive strength and excellent heat resistant adhesive strength. Further, if the light is blocked, no curing reaction occurs, so that the storage stability is also excellent.

The amount of the above-mentioned cationic photopolymerization initiator in the photoreactive hot-melt adhesive composition is determined by the type and intensity of light, the type and amount of the cationic polymerizable compound A and the cationic polymerizable compound B or C, It may be appropriately set according to the type of the cationic photopolymerization initiator and is not particularly limited, but generally, the total amount of the cationically polymerizable compound A and the cationically polymerizable compound B or C is 1
Photocationic polymerization initiator 0.01 to 100 parts by weight
It is preferably 10 parts by weight.

If the amount of the cationic photopolymerization initiator is less than 0.01 part by weight based on 100 parts by weight of the total amount of the cationically polymerizable compound A and the cationically polymerizable compound B or C, the cationically polymerizable compound A and the cationically polymerizable compound B In some cases, the photopolymerization reaction of the reactive compound B or C may not proceed smoothly. On the contrary, when the amount of the cationic photopolymerization initiator exceeds 10 parts by weight based on the total amount of 100 parts by weight, the photoreactive hot-melt type adhesive may be used. The physical properties of the cured product of the agent composition may be rather deteriorated.

The photoreactive hot-melt adhesive composition of the present invention needs to be solid at room temperature. Also,
The photoreactive hot melt adhesive composition of the present invention may have tackiness (tack) at room temperature.

The photoreactive hot-melt adhesive composition of the present invention has attained the object of the present invention in addition to the cationic polymerizable compound A, the cationic polymerizable compound B or C, and the cationic photopolymerization initiator, which are essential components. If necessary, a thermoplastic resin (including a thermoplastic elastomer) may be blended as long as it does not hinder.

The thermoplastic resin may be any resin that can be melted by heating and solidified by cooling, and is not particularly limited. Examples thereof include polyolefin resins such as polyethylene and polypropylene, polybutadiene, and the like.
Elastomers such as polychloroprene, polyisoprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polyether resins such as polyethylene oxide, polypropylene oxide, polytetramethylene oxide, polyvinyl acetate, ethylene-vinyl acetate copolymer Coal, polyvinyl chloride, ethylene-vinyl chloride copolymer, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinyl resin such as polyvinyl formal, polyvinyl butyral, polyvinyl ether, and (meth) acrylate ester Polyacrylic resin such as polymer, polystyrene resin, polyester resin, polycarbonate resin, ketone resin, acrylonitrile-styrene copolymer resin, acrylonitrile -Butadiene-styrene copolymer-based resin, etc., among which, among others, a cured product of the photoreactive hot melt type adhesive composition is excellent in adhesiveness, so that a solid thermoplastic resin at normal temperature is used. Are preferably used, and specifically, polyvinyl resins, polyacrylic resins, polyester resins, polycarbonate resins, and the like are preferably used. These thermoplastic resins may be used alone or in combination of two or more.

The mixing ratio of the thermoplastic resin to the total amount of the cationically polymerizable compound A and the cationically polymerizable compound B or C is not particularly limited. The total amount of the compound A and the cationically polymerizable compound B or C is from 5/95 to 9
It is preferably 5/5, more preferably 10/9.
0 to 80/20.

When the total amount (weight ratio) of the thermoplastic resin / the cationically polymerizable compound A and the cationically polymerizable compound B or C is less than 5/95, the effect of blending the thermoplastic resin can be sufficiently obtained. On the contrary, the total amount (weight ratio) of the thermoplastic resin / cationic polymerizable compound A and the cationic polymerizable compound B or C is 95/5.
If the ratio exceeds the above, the photoreactivity (photocurability) of the obtained photoreactive hot melt adhesive composition may be insufficient.

The photoreactive hot-melt adhesive composition of the present invention may have, if necessary, an adhesive property improving agent such as a silane coupling agent or a titanium coupling agent within a range not to impair the achievement of the object of the present invention. Benzophenone and 9,10-
Photosensitizers such as anthraquinone, dehydrating agents, antioxidants (antiaging agents), heat stabilizers, softeners, plasticizers, waxes, fillers, flame retardants, foaming agents, antistatic agents, fungicides, and viscosities One or more kinds of various additives such as an adjusting agent and a coloring agent may be blended.

One or more of the above additives are previously blended with each of the above-mentioned components such as the cationically polymerizable compound A, the cationically polymerizable compound B or C, the cationic photopolymerization initiator, and the thermoplastic resin. May be
It may be blended after preparing a composition comprising the above components.

The method for producing the photoreactive hot-melt adhesive composition of the present invention is not particularly limited, and any kneading equipment or method may be employed as long as the components to be blended can be uniformly kneaded. However, it is preferable to manufacture under appropriate heating conditions under which each component can be melted. The kneading of each component at the time of production may be carried out without a solvent, or after kneading in an inert solvent, the solvent may be removed. Specific kneading equipment is not particularly limited, for example, double helical ribbon bath, gate bath, butterfly mixer, planetary mixer, three rolls, kneader-ruder type kneader, extruder-type kneading extruder, etc. Is mentioned. Further, as these kneading equipment and kneading method, a single equipment and a single method may be used.
More than one kind of equipment and two or more kinds of methods may be used in combination.

The production of the photoreactive hot-melt adhesive composition is carried out in order to reduce the incorporation of water which is a component that inhibits the cationic polymerization of the cationically polymerizable compound A and the cationically polymerizable compound B or C. Preferably, the reaction is performed under anhydrous conditions. Further, the above production may be performed under atmospheric pressure, or may be performed under reduced pressure or under increased pressure as needed. Further, the above-mentioned production is preferably performed in a state in which light including light having a wavelength effective for initiating curing by the cationic polymerization reaction is substantially blocked. The heating temperature range during the production is not particularly limited, but is 50 to 2 hours.
50 ° C is preferable, and more preferably 80 to 200 ° C.

The thus obtained photoreactive hot-melt adhesive composition of the present invention may have tackiness (tack) at room temperature or may be non-tacky at room temperature.

In the photoreactive hot-melt adhesive composition of the present invention, the cationic polymerization reaction proceeds by irradiation with light. It is preferable to use a storage container that can be substantially shut off. Preferred storage containers include, for example, opaque containers and container materials that do not transmit light such as pail, tin can, drum, cartridge, release box, release tray, cardboard case, paper bag, and plastic container. However, the present invention is not limited to these containers and container materials. Further, the photoreactive hot melt adhesive composition of the present invention may be used immediately after production without employing these storage methods.

The method of bonding an adherend using the photoreactive hot melt adhesive composition of the present invention includes, for example,
Heat and melt the photoreactive hot melt adhesive composition,
One or both of the adherends are applied in a molten state, and the coated photoreactive hot-melt adhesive composition is irradiated with light, and then both adherends are bonded together at room temperature or under heating. A film is produced by a roll coater, a flow coater, a bar coater, or the like from a photoreactive hot-melt adhesive composition that has been heated and melted, or a film-form photoreactive hot After irradiating the melt-type adhesive composition with light, a method of bonding both adherends and bonding by bonding under normal temperature or under heating may be mentioned, but the method is limited to these bonding methods. Not something. In the case where a material that transmits light is used as the adherend, a method of irradiating light after bonding the adherend or pressing the adherend may be employed.

As a method of applying the photoreactive hot-melt type adhesive composition to an adherend by heating and melting, for example, a photoreactive hot-melt type adhesive which is heated and melted by a usual hot-melt applicator or a hot-melt coater is used. To apply an adhesive composition to an adherend, a method of immersing (dipping) an adherend in a photoreactive hot-melt adhesive composition that has been melted by heating, a photoreactivity that has been heated and melted by a hot melt air gun, etc. Examples include a method of spraying (spraying) the hot-melt adhesive composition onto an adherend, and a method of extruding and coating a photoreactive hot-melt adhesive composition heated and melted by an extruder or the like onto an adherend. However, the present invention is not limited to these coating methods.

In the above coating, the photoreactive hot-melt adhesive composition may be supplied to a hot-melt applicator or a hot-melt coater using a pail unloader or a cartridge dispenser, or may be in the form of a stick. It may be supplied to the above various coating apparatuses in the form of pellets, slugs, blocks, pillows, billets, and the like. In the heating and melting, the entire photoreactive hot-melt adhesive composition may be heated and melted, or only the photoreactive hot-melt adhesive composition located in the vicinity of the heating device may be heated and melted. May be.
In any of the above-mentioned heat-melt coating methods, it is preferable to carry out the method in a state where light including light having a wavelength effective for initiating curing of the photoreactive hot-melt adhesive composition by a cationic polymerization reaction is blocked.

The light used to excite the cationic polymerization reaction of the photoreactive hot-melt adhesive composition of the present invention may be any light as long as it can generate cations from the photocationic polymerization initiator. Can be used. The type of light may be appropriately selected according to the type of the cationic photopolymerization initiator, but is generally 200 to 600.
It is preferable to use light including light having a wavelength of nm. In particular, when an onium salt such as an aromatic iodonium salt or an aromatic sulfonium salt, a metallocene salt, or the like is used as the photocationic polymerization initiator, it is preferable to use light having a wavelength of 200 to 400 nm. The light irradiation method may be a method of directly irradiating an effective amount of light to the photoreactive hot-melt adhesive composition coated by heating and melting, or a method in which the adherend is transparent or semi-transparent. In the case of a transparent light-transmitting material, a method of indirectly irradiating an effective amount of light to the photoreactive hot-melt adhesive composition coated by heating and melting through the adherend may be used. good.

Since the amount of light irradiation varies depending on the type of the cationic photopolymerization initiator and the coating thickness and the coating amount of the photoreactive hot-melt type adhesive composition, it is difficult to determine uniquely,
Generally, it is preferable to be in the range of 0.001 to 10J. Since the photoreactive hot-melt adhesive composition of the present invention cures with a low irradiation amount of light, the coating thickness is 200 μm.
If it is on the order, it is sufficiently cured with a light irradiation amount of 60 mJ or more. The light irradiation source is not particularly limited when, for example, ultraviolet light is used as the light, and examples thereof include a fluorescent lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a chemical lamp, and a xenon lamp. These irradiation sources may be used alone or 2
More than one type may be used in combination.

The photoreactive hot-melt adhesive composition of the present invention can be sufficiently cured by irradiating light. However, if the curing time is to be further shortened, appropriate heating may be performed during or after the light irradiation. May be performed. As a heating method in this case, an appropriate method may be appropriately adopted depending on the type of the photoreactive hot melt adhesive composition, the shape and properties of the adherend, the heating conditions, and the like. , A method of placing in a heated oven, a method of heating with a heater or the like, but are not limited to these heating methods. These heating methods may be used alone or in combination of two or more.

The adherend to which the photoreactive hot melt adhesive composition of the present invention is suitably applied includes, for example, metals such as aluminum, iron and copper and alloys thereof, plastics and composites thereof, glass, Concrete, stone, gypsum, mortar, inorganic materials such as ceramics, wood, cellulose materials such as paper, various adherends such as leather,
Among them, it is particularly preferably applied to aluminum, but it is not limited to these adherends. The shape of these adherends is not particularly limited, for example, plate-like, lump-like, rod-like, sheet-like, string-like, woven, non-woven,
Any shape such as a honeycomb shape, a tubular shape, and a particle shape may be used. Further, the photoreactive hot-melt adhesive composition of the present invention may be applied to adhesion of the same type of adherend or may be applied to adhesion of a different type of adherend.

The photoreactive hot-melt adhesive composition of the present invention can be widely used, for example, as an elastic adhesive, a structural adhesive, a pressure-sensitive adhesive, a sealing agent, a coating agent and the like. Particularly preferred uses include those in which at least one adherend is aluminum. In addition, the core material of sandwich panels, such as door panels, partitions, shutters, furniture, blackboards, white boards, and panels for housing of office equipment, is bonded to the surface material, and door panels and ceiling materials for furniture, partitions, automotive interior materials, etc. It is also suitably used for applications such as adhesion between a core material and a surface material, but is not limited to these applications.

(Function) The photoreactive hot-melt adhesive composition of the present invention has a solid state at room temperature and has an average of one or more cationically polymerizable reactive groups represented by the general formula (1) per molecule. A cationically polymerizable compound in which the cationically polymerizable compound A and the cationically polymerizable compound B represented by the general formula (2) or the cationically polymerizable compound C represented by the general formula (3) are used in combination is mainly used. As a component, a cationic photopolymerization initiator is blended with this, so by irradiation of light,
The cationically polymerizable reactive group can be cured rapidly by a cationic polymerization reaction. Further, since the cationic polymerizable compound A and the cationic polymerizable compound B or the cationic polymerizable compound C are used in combination as the cationic polymerizable compound, the cured product exhibits excellent normal-state adhesive strength and excellent heat-resistant adhesive strength. I do. Furthermore, if the light is not blocked, the composition is not cured, so that it has excellent storage stability and does not contain an isocyanate compound such as a urethane prepolymer, so that it does not adversely affect the working environment.

[0061]

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”.

Example 1 (1) Preparation of Photoreactive Hot Melt Adhesive Composition Bisphenol A type epoxy resin (trade name “Epicoat 100”) which is solid at room temperature as cationically polymerizable compound A
1 ", manufactured by Japan Epoxy Resin Co., Ltd., 85 parts of a cationically polymerizable compound A (I) described in Table 1 below), and a diglycidyl compound of a polyol obtained by adding propylene oxide to bisphenol A as a cationically polymerizable compound B (I) (Trade name “Likaresin BPO-20E”, average number of propylene oxide in the molecule: about 2, manufactured by Nippon Rika Co., Ltd.) 15 parts and photocationic polymerization initiator (trade name “UV
I-6990 "(manufactured by Nippon Union Carbide Co., Ltd.), heated and melted at 150 DEG C. using a jacketed planetary mixer capable of circulating heated oil, and uniformly kneaded. A reactive hot melt adhesive composition was produced.

(2) Preparation of Composite Sheet The photoreactive hot-melt adhesive composition obtained above was applied on an aluminum sheet having a thickness of 0.3 mm at 120 ° C., and an ultra-high pressure mercury lamp of 50 mW / cm ² was used. And then irradiating with ultraviolet rays for 30 seconds so that the irradiation amount of light having a wavelength of 365 nm becomes 1500 mJ / cm ^2, and then a thickness of 0.3 prepared separately on the photoreactive hot-melt adhesive composition layer.
mm aluminum sheets were laminated and thermally laminated at 75 ° C. to produce a composite sheet.

Example 2 The composition of the photoreactive hot-melt adhesive composition was changed to a cationically polymerizable compound A, a bisphenol A type epoxy resin "Epicoat 1001" solid at room temperature (manufactured by Japan Epoxy Resin Co., Ltd.). 80 parts of a cationically polymerizable compound A (I), a diglycidyl compound of a polyol obtained by adding ethylene oxide to bisphenol A as a cationically polymerizable compound B (II) (trade name “Likaresin BEO-60E”, average number of ethylene oxide in the molecule) Photoreactive hot-melt adhesive in the same manner as in Example 1 except that 20 parts and about 1 part of a cationic photopolymerization initiator “UVI-6990” were used. A composition was prepared. Next, a composite sheet was produced in the same manner as in Example 1 except that this photoreactive hot-melt adhesive composition was used.

Example 3 The composition of the photoreactive hot melt type adhesive composition was changed to a bisphenol A type epoxy resin “Epicoat 1001” which was solid at room temperature as a cationic polymerizable compound A (manufactured by Japan Epoxy Resin Co., Ltd.). 85 parts of a cationically polymerizable compound A (I), a diglycidyl compound of a polyol obtained by adding ethylene oxide to a hydrogenated product of bisphenol A as a cationically polymerizable compound C (prototype name: “CHDM (EO) 10”, average ethylene in the molecule) Oxide number: about 10 (Yokkaichi Gosei Co., Ltd.) 15
Part and photocationic polymerization initiator "UVI-6990" 1
The photoreactive hot-melt adhesive composition was manufactured in the same manner as in Example 1 except that the above-mentioned parts were used. Next, a composite sheet was produced in the same manner as in Example 1 except that this photoreactive hot-melt adhesive composition was used.

Example 4 A photoreactive hot-melt adhesive composition was prepared by mixing a cationically polymerizable compound A with a bisphenol F type epoxy resin “Epicoat 4004P” which is solid at room temperature (manufactured by Japan Epoxy Resin Co., Ltd.). 80 parts of a cationically polymerizable compound A (II), a diglycidyl compound of a polyol obtained by adding ethylene oxide to a hydrogenated product of bisphenol A as a cationically polymerizable compound C (prototype name "CHDM (EO) 10", average ethylene in the molecule) Number of oxides: about 10, manufactured by Yokkaichi Gosei Co., Ltd.) 2
0 parts and photo cationic polymerization initiator "UVI-6990"
1 in the same manner as in Example 1 except that
A photoreactive hot melt adhesive composition was produced. Next, a composite sheet was produced in the same manner as in Example 1 except that this photoreactive hot-melt adhesive composition was used.

Comparative Example 1 The composition of the photoreactive hot-melt adhesive composition was changed to a bisphenol A type epoxy resin “Epicoat 1001” solid at room temperature as a cationic polymerizable compound A (manufactured by Japan Epoxy Resin Co., Ltd.). A photoreactive hot melt adhesive composition was prepared in the same manner as in Example 1 except that 100 parts of the cationically polymerizable compound A (I)) and 1 part of the cationic photopolymerization initiator “UVI-6990” were used. Was manufactured. Next, a composite sheet was produced in the same manner as in Example 1 except that this photoreactive hot-melt adhesive composition was used.

Performance of Composite Sheets Obtained in Examples 1 to 4 and Comparative Example 1 (Normal Adhesive Strength, Heat Resistant Adhesive Strength)
Was evaluated by the following method. The results were as shown in Table 1.

Normal adhesive strength: A T-peel test was performed on the composite sheet using a tensile tester at a measurement temperature of 23 ° C. and a peel rate of 50 mm / min, and the T-peel strength at 23 ° C. was measured. Average value is normal adhesive strength (N / m)
And Heat resistant adhesive strength: Measured at 80 ° C using a tensile tester
A T-peel test was performed on the composite sheet under the conditions of a peel speed of 50 mm / min and the T-peel strength at 80 ° C. was measured, and the average value was taken as the heat-resistant adhesive strength (N / m).

[0070]

[Table 1]

As is clear from Table 1, the photoreactive hot-melt adhesive compositions of Examples 1 to 4 according to the present invention are:
Both the normal adhesive strength and the heat resistant adhesive strength were excellent.

On the other hand, in the photoreactive hot melt adhesive composition of Comparative Example 1 in which the cationic polymerizable compounds B and C were not blended, an internal strain was generated in the cured product due to shrinkage at the time of photocuring. Since the adhesion between the adherend (aluminum sheet) and the adhesive was reduced, both the normal adhesive strength and the heat resistant adhesive strength were poor.

[0073]

As described above, the photoreactive hot-melt adhesive composition of the present invention cures rapidly by light irradiation, and after curing, has excellent normal adhesion to a wide range of adherends. Since it exhibits strength and heat-resistant adhesive strength, and has excellent storage stability and does not adversely affect the working environment, elastic adhesives for various adherends including aluminum, structural adhesives, Pressure-sensitive adhesives, sealing agents,
It is suitably used as a coating agent or the like.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J040 EC021 EC061 EC071 EE031 GA08 GA19 GA23 GA26 HB14 HC14 HD18 HD41 JB01 JB08 KA13

Claims (2)

[Claims] 1. A cationic polymerizable compound A having an average of at least one cationically polymerizable reactive group represented by the following general formula (1) per molecule and solid at room temperature, represented by the following general formula (2) A photoreactive hot-melt adhesive composition comprising a cationically polymerizable compound B and a cationic photopolymerization initiator. Embedded image (Wherein R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an isoamyl group or a phenyl group, and R ₅ , R ₆ and R ₇ represent a hydrogen atom or Represents an organic group, and k and m are 0, 1 or 2
Is shown). In the formula, R ₈ and R _{9 each} represent a hydrogen atom or a methyl group; R ₁₀ and R _{11 each} represent a cationically polymerizable reactive group represented by the above general formula (1); And n represents a positive integer of 1 or more. 2. A cationic polymerizable compound A which has at least one cationically polymerizable reactive group represented by the following general formula (1) per molecule on average and is solid at room temperature and is represented by the following general formula (3) A photoreactive hot-melt adhesive composition comprising a cationic polymerizable compound C and a cationic photopolymerization initiator. Embedded image (Wherein R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, an isoamyl group or a phenyl group, and R ₅ , R ₆ and R ₇ represent a hydrogen atom or Represents an organic group, and k and m are 0, 1 or 2
Is shown). In the formula, R ₈ and R _{9 each} represent a hydrogen atom or a methyl group; R ₁₀ and R _{11 each} represent a cationically polymerizable reactive group represented by the above general formula (1); And n represents a positive integer of 1 or more.