JPH11116929A - Reactive hot melt adhesive composition and adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a reactive hot melt adhesive compsn. which is less liable to deteriorate under heat and melt conditions, able to reduce application troubles, and less liable to deteriorate curability after photo irradiation, and to provide an adhesion method. SOLUTION: This reactive hot melt adhesive composition comprises a cation polymerization compd., a cation polymerization initiator to cure the cation polymerization compd. by photo irradiation, a stabilizer, and a compd. contg. a sulfur atom and a phenol group in one molecule. In the adhesion method, the reactive hot melt adhesive composition is heated and melted, and pasted on at least one of the bodies to be adhered, and, after irradiating photo energy, both of them are attached and pressed under room temperature or under heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactive hot-melt adhesive composition which is applied by heat-melt coating and cures by light irradiation, and a bonding method using the same. The present invention relates to a reactive hot melt adhesive composition and a bonding method capable of reducing deterioration in a molten state.

[0002]

2. Description of the Related Art Hot melt adhesives are widely used to bond paper, fiber, wood, glass, plastic or metal in various fields such as bookbinding, wrapping, textile processing, woodworking, light electric or transportation. ing.

When bonding with a hot melt adhesive, the hot melt adhesive is usually heated and melted at a temperature of about 70 to 200 ° C. in an applicator. Next, a hot melt adhesive in a molten state is applied to the adherends, and the adherends are bonded to each other. The adherends are bonded to each other by cooling and solidifying the hot melt adhesive.

[0004] In the case of hot melt adhesives, the adhesive strength is rapidly increased by cooling and solidification. Therefore, the time from bonding the adherends to realizing sufficient adhesive strength is very short, usually 1 minute or less. Therefore, the bonding operation can be completed in a short time.

[0005] However, hot melt adhesives can be used in an applicator at high temperatures, ie, 100-200.
Although it is heated and melted at a temperature of about ° C., it takes a long time to melt, so it is necessary to melt a larger amount of hot melt adhesive in the applicator than is actually used. For this reason, hot melt adhesives are usually kept at a high temperature for a long time in an applicator.

In some cases, the hot-met adhesive is kept at a high temperature for a long time on the hose of the applicator, inside the gun, and on the heating roll. In these cases, the hot-melt adhesive in the molten state is degraded by heat and decomposed, cross-linked, carbonized or adhered to the surface,
In some cases, the gun of the applicator was clogged or the amount of application fluctuated. In addition, the adhesive performance after application may be reduced.

Therefore, in order to prevent the deterioration in the molten state, a method of adding a small amount of a stabilizer to the hot melt adhesive has been conventionally attempted. However, in the case of reactive hot melt adhesives that cure with moisture, there are not many stabilizers that exhibit sufficient effects, and there is a possibility that the adhesive performance after application may be adversely affected. I didn't.

As another application, there is known an ultraviolet-crosslinkable solid composition used as a powder coating material, which has improved storage stability before irradiation (Japanese Patent Application Laid-Open No. Hei 7-1995).
-252344). In this prior art, a solid epoxy resin composition containing an epoxy compound having a glass transition point Tg higher than 35 ° C., a cationic photopolymerization initiator, and a polyfunctional nucleophilic chain transfer agent is disclosed. It is said that the storage stability of the compound is increased, the fluidity at a temperature lower than 130 ° C. is kept good, and sufficient reactivity is maintained.

However, even when the solid epoxy resin composition is maintained at a temperature of 130 ° C. or more for a long time, gelation occurs, the viscosity increases, and good fluidity cannot be obtained.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reactive hot melt which is hardly deteriorated when melted by heating at a high temperature, has good fluidity at the time of melt coating, and promptly causes a curing reaction when irradiated with light. An object of the present invention is to provide an adhesive and a bonding method using the same.

[0011]

Means for Solving the Problems The present invention has been made to achieve the above object, and the reactive hot melt adhesive composition according to the first aspect of the present invention comprises a cationically polymerizable compound. A cationic polymerization initiator for curing the cationically polymerizable compound by light irradiation, and a stabilizer comprising a compound having a sulfur atom and a phenol group in one molecule.

The invention according to claim 2 is characterized in that the stabilizer is:
It is characterized by being composed of a compound having a sulfur atom and a phenol group directly connected to an aromatic molecule in one molecule.
In the invention according to claim 1 or 2, preferably, as described in claim 3, as the cationically polymerizable compound, a compound having an average of one or more of a structure represented by the following formula (1) per molecule or An epoxy compound having an average of one or more epoxy groups per molecule is used.

[0013]

Embedded image

In the equation (1), m and n are 0,
1 or 2, R ¹ , R ² , R ³ and R ⁴ are a methyl group,
It is an ethyl group, an isopropyl group, an isoamyl group, a phenyl group or a hydrogen atom.

Further, the cationic polymerization initiator includes:
Preferably, at least one selected from the group consisting of an aromatic iodonium salt, an aromatic sulfonium salt and a metallocene salt, and an arylsilanol-aluminum complex is used.

The invention described in claim 5 is the first invention.
4. The reactive hot melt adhesive composition according to any one of (1) to (4), which is heated and melted, and is applied in a molten state to one or both of the adherends, and the applied reactive hot melt adhesive composition is irradiated with light. After that, the adherends are attached to each other and pressure-bonded to each other. Hereinafter, details of the present invention will be described.

(Cationically polymerizable compound) In the present invention, the above-mentioned cationically polymerizable compound is an organic compound having a portion which can be increased in molecular weight by cationic polymerization. The cationically polymerizable compound may be any of a monomer, an oligomer and a polymer, and may include carbon, hydrogen, oxygen,
It may contain organic compound constituent atoms such as nitrogen, sulfur and phosphorus.

The portion that can be made high molecular weight by cationic polymerization may be present at any of the terminal, side chain and in the molecular skeleton of the molecular skeleton. Furthermore, the specific structure and molecular weight of the cationically polymerizable compound are not particularly limited.

The cationically polymerizable compound itself may be a hot-melt resin, and in that case, the hot-melt resin described below may not be used. In addition, the cationically polymerizable compound does not necessarily need to constitute the hot melt component in the hot melt adhesive composition according to the present invention, and may be a liquid compound at room temperature. Is mixed with the hot melt resin.

Specific examples of the cationic polymerizable compound include cyclic ether compounds (such as epoxy compounds, oxetane compounds, and oxolane compounds), cyclic ester compounds, and vinyl ether compounds. These cationically polymerizable compounds may be used alone or in combination of two or more.

The cationically polymerizable compound preferably comprises a compound having at least one structure represented by the formula (1) on an average per molecule. Further, it is more preferable to use a compound having an average of two or more structures of the formula (1) per molecule.

As the cationically polymerizable compound, an epoxy compound is preferably used because of its excellent cationic polymerizability. Examples of the epoxy compound include an organic compound having at least one oxirane ring polymerizable by cationic polymerization, and may be a monomer, an oligomer, or a polymer, and may be any of aliphatic, alicyclic, and aromatic epoxy compounds. It may be a compound. The epoxy compound preferably has an average of 1 per molecule.
It has the above-mentioned epoxy group, and more preferably has an average of 2 or more epoxy groups per molecule.

The number of the “average” per molecule of the structure of the formula (1) or the epoxy group is determined by the number of the structure of the formula (1) or the number of the epoxy group in the compound. By the total number of compounds or epoxy molecules having the formula:

As the epoxy compound which is a polymer,
A linear polymer having a terminal epoxy group (for example, diglycidyl ether of polyoxyalkylene glycol), a polymer having an oxirane unit in its skeleton (for example, polybutadiene polyepoxide), and a polymer having an epoxy group in a side chain (glycidyl (meth) A) acrylate polymers or copolymers).

The molecular weight of the epoxy compound is not particularly limited, but may range from about 58 to about 100,000. Specific examples of the epoxy compound include, for example, aromatic epoxy resins such as bisphenol A type epoxy resin, alicyclic epoxy resins such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and Methylolpropane triglycidyl ether, 2,2-bis [4- (2,3
-Epoxypropoxy) cyclohexyl] propane, aliphatic epoxy resin, (meth) acrylate polymer or copolymer having an oxirane ring in the molecule such as glycidyl (meth) acrylate, epoxidized polybutadiene, and butadiene and other monomers And epoxidized copolymers of the above, modified products of these epoxy resins, and the like, but are not limited thereto. Further, the above epoxy compounds may be used alone or in combination of two or more.

(Cationic polymerization initiator) The cationic polymerization initiator is not particularly limited as long as it can generate a cation for initiating polymerization of the cationically polymerizable compound by light irradiation. Preferably, an aromatic iodonium salt, an aromatic sulfonium salt, and / or a metallocene salt, and an arylsilanol-aluminum complex are used. The aromatic iodonium salt and aromatic sulfonium salt effective as a cationic polymerization initiator,
For example, it is disclosed in U.S. Pat. No. 4,256,828. Further, regarding metallocene salts, US Pat.
No. 89,536. The amount of the cationic polymerization initiator varies depending on the type and intensity of light, the type and amount of the cationic polymerizable compound, the type of the cationic polymerization initiator, and the like, but is preferably 0.1 to 100 parts by weight of the cationic polymerizable compound. 01 to 10 parts by weight are blended.

(Stabilizer) In the present invention, the above-mentioned stabilizer is blended in order to prevent deterioration in a heated and molten state. This stabilizer is a compound having a sulfur atom and a phenol group in one molecule, and preferably a compound having a sulfur atom and a phenol group directly connected to an aromatic molecule in one molecule. This stabilizer may or may not contain a nitrogen atom. However, in order to maintain good heat-melt stability and curing reactivity after coating, the aromatic atom is contained in one molecule as described above. It is desirable that the compound be a compound having a sulfur atom and a phenol group directly bonded to the compound.

Examples of the compound used as the stabilizer include hindered phenol compounds and phosphorus compounds. More specifically, compounds having a sulfur atom and a phenol group in one molecule include Ciba Geigy Corporation. Trade name: Irganox 565L or a compound having a sulfur atom and a phenol group directly connected to an aromatic group in one molecule, manufactured by Ciba-Geigy, trade name: Irganox 565
And the like.

The compounding ratio of the stabilizer varies depending on the type and intensity of light to be irradiated, the type and mixing ratio of the cationically polymerizable compound, the type of the cationic polymerization initiator, and the like. The ratio is 0.01 to 10 parts by weight with respect to 100 parts by weight. If the compounding ratio of the stabilizer is less than 0.01 part by weight, the effect of preventing deterioration during heating and melting may not be sufficiently obtained. If it exceeds 10 parts by weight, the curing reactivity after application may be insufficient. May drop.

(Other components that can be added) The reactive hot melt adhesive composition according to the present invention may contain a hydroxyl compound, if necessary. The hydroxyl compounds that can be used can be liquid or solid, but have at least one, and preferably at least two, hydroxyl groups. In this case, the hydroxyl group may be at the terminal of the compound or may be present in a side group of the polymer or copolymer.

Examples of the hydroxyl compound include, but are not limited to, alkylene glycol, polyhydroxyalkane, and polyoxyalkylene polyol. The hydroxyl compound may be added alone or in combination of two or more.

In the reactive hot melt adhesive composition according to the present invention, a hot melt resin may be added as required. That is, when the cationically polymerizable compound itself is a hot-melt resin, it is not necessary to use another hot-melt resin, but another hot-melt resin may be added. When the reactive compound is not a hot melt resin,
A hot-melt resin is added to enable it to be used as a hot-melt adhesive.

As the hot melt resin, those having an appropriate molecular weight from low molecular weight to high molecular weight can be used. For example, tackifying resins such as styrene resin, petroleum resin and natural resin can be used. Resin, polyolefin resin such as ethylene-vinyl acetate copolymer resin, rubber resin such as butadiene-styrene block copolymer, acrylic copolymer resin, polyester resin or hot melt type thereof Various modified products of the resin can be exemplified, but not limited thereto, and two or more of these hot melt resins may be used in combination.

The reactive hot melt adhesive composition according to the present invention may further contain, if necessary, an adhesion improver (such as a silane coupling agent or a titanium coupling agent), a sensitizer, a dehydrating agent, Anti-aging agents, stabilizers, plasticizers, waxes, fillers, flame retardants, foaming agents, antistatic agents, fungicides,
Components such as a viscosity modifier can be added, but other components that can be added are not limited to the above components. Further, two or more kinds of the above-mentioned components may be added. In addition, these components may be added in advance during the production of the above-described hot melt resin, and such a case is also acceptable.

(Method for Producing Reactive Hot-Melt Adhesive Composition) The method for producing the reactive hot-melt adhesive composition according to the present invention is not limited as long as the components to be blended can be mixed and uniformly dispersed. Although a method may be adopted, it is necessary to manufacture under appropriate heating conditions under which the used materials can be melted. In addition, the mixing and dispersion of each component at the time of production may be performed without a solvent or may be performed in an inert solvent. Specifically, it can be performed using one or more of a double helical ribbon bath or gate bath, a butterfly mixer, a planetary mixer, a three-roll, a kneader-ruder kneader or an extruder-type kneader extruder. However, the apparatus for kneading each component is not limited to these.

Regardless of the type of equipment used for mixing and dispersing the components, it is preferable to mix and disperse the components under anhydrous conditions because the amount of water, which is a component inhibiting cationic polymerization, is reduced.

When mixing and dispersing the components, the components are mixed and dispersed at atmospheric pressure or, if necessary, at or above atmospheric pressure. In addition, the order of adding each component at the time of production is not particularly limited, but in order to shorten the melting time or reduce the deterioration of the obtained composition, generally, it is difficult to melt, or at the time of melting. It is desirable to charge in order from the one that is hardly deteriorated by heat or mechanical shearing force.

The above stabilizer has an effect of preventing the composition from deteriorating due to heat or mechanical shearing force at the time of melting. Therefore, it is desirable to charge the stabilizer at the earliest possible stage. Since it is liable to be decomposed or deteriorated by mechanical shearing force, it is desirable to feed it last.

When producing the reactive hot melt adhesive composition according to the present invention, it is necessary to carry out the production in a state where light effective for starting curing is blocked. The method for storing the reactive hot melt adhesive composition is not particularly limited as long as it can block light effective for initiating curing, but preferred storage containers include pale cans, tin cans, drums, and cartridges. , A release box, a release tray, a cardboard container, a paper bag, a plastic bag (for example, a composite film in which an aluminum foil is sandwiched), and a container opaque to light effective for initiating curing. However, it is not limited to these containers, and the material of these containers is not particularly limited as long as light can be blocked. Further, the reactive hot melt adhesive composition according to the present invention may be used immediately after production without being stored.

(Adhesion method) In the adhesion method according to the fifth aspect of the present invention, the reactive hot melt adhesive composition is heated and melted, and is applied to one or both of the adherends in a molten state. The reactive hot melt adhesive composition is irradiated with light, the adherends are adhered to each other, and bonded by pressing.

The method for applying the reactive hot melt adhesive composition by heating and melting is not particularly limited. For example, the hot melt adhesive composition heated and melted by an ordinary hot melt applicator or a hot melt coater may be used. A method of applying the adhesive composition to an adherend,
A method of immersing an adherend in a hot-melt reactive hot-melt adhesive composition, a method of spraying a hot-melt adhesive composition being heated and melted on an adherend by a hot-melt air gun, an extruder, etc. And extruding the hot melt adhesive composition heated and melted on the surface of the adherend.

The hot melt adhesive composition may be supplied to the hot melt applicator using a pail unloader, a cartridge dispenser, or the like, and the hot melt adhesive composition may be applied in the form of a stick, pellet, slug, block, pillow, billet, or the like. The apparatus may be supplied with a hot melt adhesive composition.

As for the heating, the entire reactive hot melt adhesive composition may be heated and melted, or may be heated and melted only in the vicinity of the heating body. In any case of using any of the melt coating methods, it is desirable that the melt coating be performed in a state where light effective for starting curing is blocked.

As the light, any light can be used as long as a cation can be generated from the above-mentioned cationic polymerization initiator, and the type of light is appropriately selected according to the type of the cationic polymerization initiator. UV light is used. Preferably, light having a wavelength of 200 to 600 nm is used. Particularly, when an aromatic iodonium salt, an aromatic sulfonium salt, or a metallocene salt is used as the cationic polymerization initiator, light having a wavelength of 200 to 400 nm is used. It is desirable to use.

The irradiation amount of the light also varies depending on the type of the cationic polymerization initiator and the thickness and the amount of the portion to which the reactive hot melt adhesive composition is applied. It is desirable to set it in the range of 0.001 J to 10 J.

When ultraviolet rays are used as the light source, those generally used as ultraviolet irradiation sources such as a fluorescent lamp and a high-pressure mercury lamp can be used. As for the method of irradiating the light, the hot melt adhesive may be directly irradiated, or a method of irradiating the hot melt adhesive with an effective amount of light through a transparent or translucent adherend may be employed. However, there is no particular limitation.

Regarding the method of bonding and pressing the adherends, after applying the reactive hot melt adhesive composition to one adherend, the other adherend is adhered and required under appropriate pressure and temperature. For example, a method of applying pressure for an appropriate time, a method of applying a reactive hot melt adhesive composition to both adherends, and applying pressure at an appropriate pressure and temperature for a necessary time can be exemplified.

The reactive hot-melt adhesive composition according to the present invention can be sufficiently cured by the above-mentioned light irradiation under normal conditions. However, if it is desired to further shorten the curing time, it can be heated to an appropriate temperature. Good. In this case, the heating method cannot be uniquely determined because it differs depending on the type of the reactive 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, and the like may be used, and two or more of these may be used in combination. However, the heating method is not limited to the above method. The heating temperature when shortening the curing time is preferably lower than the temperature at which the reactive hot melt adhesive composition itself softens. Otherwise, the softening of the composition may cause displacement of the bonded portion.

(Adherend to be Applied) The adherend to which the reactive hot melt adhesive composition according to the present invention is applied and the adherend to be used in the bonding method according to the present invention are particularly limited. Although not a thing, for example, metals or alloys such as iron and aluminum, plastics or plastic mixtures, inorganic materials such as glass, concrete, stone, mortar, and ceramics, cellulosic materials such as wood and paper, and a wide range of materials such as leather It can be applied to adherends. Also, regarding the shape of the adherend,
A rod, a sheet, a string, a fiber, a honeycomb, a tube, a particle, and the like may be used in any appropriate form, and it is also possible to use a different form for attaching an adherend.

(Use) The reactive hot melt adhesive composition according to the present invention is used as a reactive hot melt adhesive, particularly as an elastic adhesive, a structural adhesive, a pressure-sensitive adhesive, a sealing material, and the like. be able to. Such reactive hot melt adhesive composition, for example, door panels,
Adhesion of core and surface materials for sandwich panels such as partitions, shutters, furniture, blackboards, white boards, and panels for housing of office equipment, and core and surface materials for furniture, partitions, door panels and ceiling materials for automotive interior materials, etc. It is preferably used for applications such as bonding. However, the use of the reactive hot melt adhesive is not limited to the above use.

The reactive hot melt adhesive composition according to the invention described in the action claim 1-4, melted by heating, to soften, applying to an adherend in the same manner as normal hot-melt adhesive be able to. Further, since the adhesive hardly deteriorates due to the action of the above-mentioned stabilizer in the heat-melted state, the adhesive can be kept in the heat-melted state for a long time, and therefore, troubles due to thermal deterioration of the hot-melt adhesive during continuous use can be reduced. Can be. Furthermore, after application to the adherend, the cationic polymerization initiator generates cations by irradiating light, and the cations polymerize the cationically polymerizable compound, and have a high molecular weight, and the curing proceeds, so that the heat resistance is excellent. A cured adhesive product can be obtained and the hot-melt adhesive is hardly deteriorated by heat, so that the designed adhesive performance can be surely exhibited.

Therefore, since the curing is started only by the irradiation of the light, the reactive hot melt adhesive composition is applied to the adherend, and then the light is irradiated in accordance with the timing of the bonding. It is possible to prevent the curing from proceeding before. That is, by setting the timing of light irradiation, the application time can be set to a sufficient length.

In addition, since curing proceeds by light irradiation, the time from bonding to the development of heat resistance is not affected by the humidity of the surrounding atmosphere. Claim 2
In the invention described in the above, since a compound having a sulfur atom and a phenol group directly connected to an aromatic molecule in one molecule is used as the stabilizer, the stability of the hot melt adhesive in a heated and molten state is further enhanced, and The coating trouble at the time of use can be more effectively prevented.

According to the third aspect of the present invention, the cationically polymerizable compound is an epoxy compound having an average of one or more epoxy groups per molecule or a compound having an average of one or more structures of the formula (1) per molecule. Due to this structure, the light irradiation rapidly causes ring-opening polymerization and cure. Therefore, the adherends can be firmly bonded to each other, and the heat resistance can be improved.

In the invention according to claim 4, an aromatic iodonium salt, an aromatic sulfonium salt and / or a metallocene salt, and an arylsilanol / aluminum complex are used as the cationic polymerization initiator.
By irradiating with light having a wavelength of nm, curing can proceed promptly and an adhesive having excellent storage stability can be obtained.

According to the fifth aspect of the present invention, the first to fourth aspects are provided.
After heating and melting the reactive hot melt adhesive composition according to any one of the above, it is applied in a molten state to one or both of the adherends, and the light is applied to the applied reactive hot melt adhesive composition. After the irradiation, the adherends are bonded together, and the bonding is performed by pressure bonding at room temperature or under heating.
By setting the timing after the application until the light irradiation, the application time can be extended. That is, by extending the time from application to irradiation with light, the application time can be extended, and the optimal application time can be set according to the application and the bonded portion.

In addition, since the above-mentioned stabilizer hardly causes thermal deterioration in the heat-melted state, troubles when applying the hot-melt adhesive composition to the adherend after heat-melting can be reduced.

In addition, since the curing of the reactive hot-melt adhesive composition proceeds only by light irradiation, the time required for the heat resistance to develop varies depending on ambient humidity and weather. Difficult to do.

[0059]

The present invention will be clarified by the following non-limiting examples.

(Epoxy Resin Used) In the following Examples and Comparative Examples, one or more of the following epoxy resins were appropriately used. Epoxy resin 1: alicyclic epoxy resin manufactured by Union Carbide Japan Co., Ltd., trade name: ERL4221, pour point-3
7 ° C, epoxy equivalent 131-143. Epoxy resin 2: Epoxidized styrene-butadiene-styrene, manufactured by Daicel Chemical Industries, Ltd., trade name: Epofriend A1020, 180 ° C. melt viscosity 4170 poise, butadiene / styrene weight ratio 60/40.

(Stabilizers Used) In the following Examples and Comparative Examples, the following stabilizers were appropriately used. Stabilizer 1: Stabilizer manufactured by Ciba-Geigy, trade name: Irganox 1520L (liquid at normal temperature), a compound having a sulfur atom and a phenol group in one molecule. Stabilizer 2: Stabilizer manufactured by Ciba-Geigy Corp., trade name: Irganox 565 (melting point: 91 to 96 ° C.), a compound having a sulfur atom directly connected to an aromatic atom and a phenol group in one molecule. Stabilizer 3: Stabilizer manufactured by Ciba-Geigy Corporation, trade name: Irganox 1010 (melting point: 110 to 125 ° C.), a compound containing no sulfur atom in one molecule and having a phenol group.

(Example 1) 50 parts by weight of an epoxy resin 1, 50 parts by weight of a tackifying resin (hydrogenated petroleum resin manufactured by Mitsui Petrochemical Co., Ltd., trade name: FTR6125, softening point 125 ° C), and cationic polymerization As an initiator, an aromatic sulfonium salt-based cationic polymerization catalyst manufactured by Asahi Denka Kogyo KK, trade name: S
P-170 (liquid at normal temperature, catalyst: solvent = 50: 50)
5 parts by weight (catalyst amount) and 0.5 parts by weight of Stabilizer 1 (manufactured by Ciba Geigy, trade name: Irganox 1520L) are put into a planetary mixer provided with a jacket through which heated oil can be circulated. Then, the whole was covered with an aluminum foil, and mixed at 30 ° C. for 60 minutes at a temperature of 150 ° C. to prepare a reactive hot melt adhesive composition.

Example 2 Instead of stabilizer 1, stabilizer 2
(Ciba Geigy, product name: Irganox 56
A reactive hot melt adhesive composition was obtained in the same manner as in Example 1 except that 5) was used.

Example 3 40 parts by weight of the epoxy resin 1, 20 parts by weight of the epoxy resin 2, 40 parts by weight of the tackifying resin used in Example 1, and the cationic photopolymerization initiator 0 used in Example 1 A reactive hot melt adhesive composition was prepared in the same manner as in Example 1, except that 0.5 part by weight of Stabilizer 2 and 0.5 part by weight of Stabilizer 2 were used.

Comparative Example 1 A reactive hot melt adhesive composition was prepared in the same manner as in Example 1 except that no stabilizer was used.

(Comparative Example 2) As stabilizer, stabilizer 3 (trade name: Irganox 1010, manufactured by Ciba-Geigy)
A reactive hot melt adhesive composition was obtained in the same manner as in Example 1 except that 0.5 part by weight was used.

Comparative Example 3 A reactive hot melt adhesive composition was prepared in the same manner as in Example 3 except that stabilizer 3 was used instead of stabilizer 2.

(Evaluation) [1] Evaluation of Initial State For each of the reactive hot melt adhesive compositions obtained in Examples and Comparative Examples, the appearance and melt viscosity at 150 ° C. of the initial state were measured in the following manner. .

Appearance: The reactive hot melt adhesive composition maintained at 150 ° C. was placed in a 149 ml mayonnaise bottle in an amount of 8
0 ml was charged, the mayonnaise bottle was tilted, and the fluidity and appearance of the contents were observed. A spatula made of stainless steel was inserted into the contents, and the fluidity and appearance were observed.

Melt viscosity: 150 of hot melt adhesive
The viscosity at ℃ is a fluorescent lamp (Rapid white, manufactured by Matsushita Electric Industrial Co., Ltd., product number: FLR4)
0L-W-SDL. NU /. M. , 40W) Brookfield BM placed in a room illuminated only by
It measured according to JIS-K-6862 using a mold viscometer. Further, the reactive hot melt adhesive composition maintained at 150 ° C. was irradiated with UV light in the following manner,
The cured state after V light irradiation was evaluated.

Cured state after UV light irradiation: about 2 g of a hot-melt adhesive was dropped on a 50 μm PET (polyethylene terephthalate) film, and another release surface of a PET film was placed on the hot-melt adhesive. Crushed with a finger, and then the PET film above was removed. Using a fluorescent lamp (manufactured by Toshiba Lighting & Technology Corp., 20W chemical lamp, product number: FL20S · BL) as the thin film-like hot melt adhesive, 365 nm
UV light was applied for 60 seconds so that the intensity in the wavelength range of 2.7 W / cm ² was obtained. Next, after leaving at room temperature for 24 hours, the PET film was removed from the cured product with a finger,
It was collected in a ml sample tube, the weight of the cured product was measured, 45 ml of methylene chloride was charged, and the mixture was allowed to stand for 24 hours.
Thereafter, the mixture was filtered through a 200-mesh wire net, dried at 110 ° C. for 3 hours, the dry weight was measured, and the gel fraction was calculated based on the following equation. Gel fraction (%) = (residual dry weight (g) / cured product weight (g)) × 100

[2] Evaluation after 150 ° C. × 24 hours The reactive hot-melt adhesive composition was coated with a fluorescent lamp (Rapid white, manufactured by Matsushita Electric Industrial Co., Ltd., product number: FLR40S · W-SDL) cut off ultraviolet rays of a specific wavelength. .NU. /.
M. , 149ml in a room lit with only 40W
Was placed in a hot air dryer set at 150 ° C., and left for 24 hours. In addition, about the hot-air dryer, it was comprised so that light might not enter from a window and a ventilation opening.

After standing for 24 hours, the mayonnaise bottle was taken out of the hot-air dryer in the same manner as in the observation of the appearance in the initial state, the mayonnaise bottle was tilted in a hot state, and the fluidity and appearance of the contents were observed. A spatula made of stainless steel was inserted into the contents, and the fluidity and appearance were observed.

Melt viscosity: 24 ° C. at 150 ° C. as described above
After leaving for a period of time, the melt viscosity after 150 ° C. × 24 hours was measured at 150 ° C. in the same manner as the measurement of the melt viscosity in the initial state.

Cured state after UV light irradiation: After leaving at 150 ° C. for 24 hours as described above, UV light irradiation is performed in the same manner as in the initial state, and the cured state after UV light irradiation is determined. The rate was measured. The results are shown in Tables 1 and 2 below.

[0076]

[Table 1]

[0077]

[Table 2]

As is clear from Table 2, in Comparative Example 1,
Because it does not use a stabilizer, it remains solid at 150 ° C. after standing at 150 ° C. for 24 hours, making it impossible to measure the melt viscosity.
It could not be cured by light irradiation.

In Comparative Example 2 as well, because of the use of stabilizer 3 containing no sulfur, similar to Comparative Example 1, 150
When left at 24 ° C. for 24 hours, it solidified, the melt viscosity could not be measured, and it could not be used as a reactive hot melt adhesive.

Also, in Comparative Example 3, because the stabilizer 3 was used, the color was changed to brown and gelled after being left at 150 ° C. for 24 hours, and the melt viscosity was remarkably high at 97000 cps.

On the other hand, in Examples 1 and 2, the liquid state can be maintained at 150 ° C. even after standing at 150 ° C. for 24 hours, probably because of the use of the stabilizer 1 or 2. The gel fraction was 40
% And 50%.

In Example 3, similarly, at 150 ° C.
Even after maintaining for 4 hours, it remains liquid and has a melt viscosity of 4
It was relatively low at 200 cps, and thus could be used as a reactive hot melt adhesive, and it was possible to achieve a gel fraction of 60% by irradiation with UV light.

[0083]

The reactive hot-melt adhesive composition according to the first to fourth aspects of the present invention can be easily applied by heating and melting similarly to a conventional hot-melt adhesive, and can be cationically polymerized. Since the compound is cured by increasing the molecular weight, the heat resistance of the cured adhesive product is increased. further,
Since a stabilizer comprising a compound having a sulfur atom and a phenol group in one molecule is blended, thermal deterioration in a heated and melted state hardly occurs. Therefore, even when used continuously for a long time, coating trouble in the hot melt applicator hardly occurs.

Therefore, it can be used continuously for a long time,
In addition, workability at the time of application can be improved. In addition, the curing does not proceed until the molecular weight of the cationically polymerizable compound is increased by irradiation with light, so after applying the reactive hot melt adhesive composition, by timing the irradiation with light, The coating time can be extended. That is, even if the time until the light irradiation is extended after the application, the curing does not proceed until the light irradiation is performed, so that the adherends can be easily bonded to each other.

Therefore, depending on the application and the situation of the bonded portion,
The painting time can be set to an optimal time. In addition, the time required for the cured adhesive to exhibit heat resistance after lamination is not significantly affected by the season or weather.

In the second aspect of the present invention, since a stabilizer having a sulfur atom directly connected to an aromatic atom and a phenol group in one molecule is used as the stabilizer, the hot melt adhesive in a heated and molten state is used. Deterioration can be prevented more effectively, and coating troubles during long-time use can be further reduced.

In the bonding method according to the present invention, the reactive hot melt adhesive composition according to the present invention is heated and melted,
At least one of the adherends is applied in a molten state, the adherents are adhered to each other after irradiating the applied reactive hot melt adhesive composition with light, and pressed at room temperature or under heating, By adjusting the time from the application to the irradiation of light, the application time can be easily controlled according to the type of the adherend and the bonded portion. It is possible to reliably bond the two together and to provide an adhesive cured product having excellent heat resistance.

In addition, the action of the stabilizer enhances the stability at the time of heating and melting, and hardly causes thermal deterioration. Therefore, for example, it is possible to reduce coating troubles when coating with a hot melt applicator. Since long-term continuous use is possible and the curability after light irradiation is not reduced, the final heat resistance of the bonded product can be exhibited.

Claims (5)

[Claims] 1. A composition comprising a cationic polymerizable compound, a cationic polymerization initiator for curing the cationic polymerizable compound by light irradiation, and a stabilizer comprising a compound having a sulfur atom and a phenol group in one molecule. Reactive hot melt adhesive composition. 2. The reactive hot melt adhesive composition according to claim 1, wherein the stabilizer is a compound having a phenol group and a sulfur atom directly connected to an aromatic molecule in one molecule. 3. The compound according to claim 1, wherein the cationically polymerizable compound is a compound having a structure represented by the following formula (1) having an average of 1 or more per molecule or an epoxy compound having an average of 1 or more epoxy groups per molecule. The reactive hot melt adhesive composition according to any one of the above. Embedded image In the formula (1), m and n are 0, 1 or 2,
R ¹ , R ² , R ³ and R ⁴ are a methyl group, an ethyl group, an isopropyl group, an isoamyl group, a phenyl group or a hydrogen atom. 4. The method according to claim 1, wherein the cationic polymerization initiator comprises an aromatic iodonium salt, an aromatic sulfonium salt, and a metallocene salt.
The reactive hot melt adhesive composition according to any one of claims 1 to 3, wherein the composition is at least one selected from the group consisting of arylsilanol / aluminum complexes. 5. The reactive hot melt adhesive composition according to claim 1, which is heated and melted and applied to one or both of the adherends in a molten state. A bonding method comprising irradiating the adhesive composition with light, bonding the adherends together, and pressing the adherend.