JPH05132656A - Supercritical fluid adhesive and production of planar space heating equipment using the same - Google Patents

Abstract

PURPOSE:To obtain the subject quick-drying and pollution-free adhesive without using a large quantity of solvent or dispersion medium, thus suitable for manufacturing an inexpensive and efficiently productive planar space heating equipment by compression of an adhesive composition containing an adhesive prepolymer and carbon dioxide under high pressures. CONSTITUTION:The objective supercritical fluid adhesive is obtained by compression, under high pressures, of an adhesive composition containing (A) either an adhesive prepolymer or an aqueous emulsion and (B) carbon dioxide. In terms of causing virtually no pollution, the adhesive prepolymer is pref., a moisture-setting polyurethane-based adhesive such as a moisture-reactive urethane polymer prepared by reaction of an alkyl ether polyol with an isocyanate among various kinds thereof. The aqueous emulsion is pref., an ethylene-vinyl acetate copolymer in terms of bond strength etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel supercritical adhesive and a method for manufacturing a surface warming tool using the same, and more particularly to a surface warming tool having a fibrous surface mounting member such as an electric carpet. Is effective in the field of.

[0002]

2. Description of the Related Art Adhesives, which are conventionally solvent type, are generally composed of a polymer, an active solvent (good solvent) and a diluting solvent (poor solvent). In addition to such solvent type adhesives, generally, there are various types of adhesives such as an aqueous emulsion type, a polymerization type and a hot melt type, which have low pollution properties. In addition, various methods such as brush coating, spraying, and roll coating are used as the coating method of the adhesive.

On the other hand, for adhesion of a sheet heating device having a large adhesion area such as an electric carpet, a hot-melt adhesive represented by polyethylene or a moisture-curable polyurethane (Japanese Patent Publication No. 63-19992, 62-53) is generally used.
911), or an aqueous emulsion. Aqueous emulsion is good because it is water-based and non-polluting,
It takes a long time to dry. Therefore, a drying method by hot pressing or an adhesion method by dielectric heating (Japanese Patent Laid-Open No. 1-2943).
92, 1-296583) and the like are used.

[0004]

Solvent-type adhesives, which have been used exclusively in the past, are useful for local adhesion, but they are of good quality when it is necessary to apply good quality adhesion over a large area. An adhesive coating film is required, and for this purpose a large amount of diluting solvent is added to reduce the viscosity of the paint. Diluting by adding a large amount of this solvent is not only the solvent type, but also the aqueous emulsion type, polymerization type or hot melt type adhesives,
Then, there is a problem that the diluent solvent is hard to volatilize at the time of adhesion.

[0005] This problem is, in particular, for quickly adhering a sheet heating device having a large adhering area, there is a problem of pollution of waste of volatile solvent, a problem of installing a large applicator, a problem of adhering speed, and an adhesive cost. Due to problems and the like, none of the above adhesives was a sufficient adhesive. Furthermore, the method of spray-coating a non-polluting and inexpensive aqueous emulsion adhesive is a good method without requiring large coating equipment, but it takes a long time to dry the aqueous emulsion adhesive, which is a major problem. It was The reason for this is that the viscosity required for atomization by spraying or good quality coating is much lower than the viscosity required for film formation, and a large amount of water is required in the adhesive.

[0006] Further, in the method of hot press drying using an aqueous emulsion that has been proposed in the step of adhering the surface warming tool, when the surface warming tool is, for example, an electric carpet or the like, the covering member is a pile material or the like. Had a problem that the pile collapsed due to heat pressure. In addition, the bonding method using dielectric heating has a problem in that a conductor such as a heater wire is included in the bonding portion and microwaves are absorbed and bonding conditions are difficult.

Therefore, the present invention uses such a large amount of solvent
A first object of the present invention is to provide a novel supercritical fluid adhesive that does not require a dispersion medium, is instantly dry, and is pollution-free.

A second object of the present invention is to provide a method for producing a surface warming tool which is high in production efficiency, inexpensive and non-polluting, using this supercritical fluid adhesive.

[0009]

In order to achieve the first object, the present invention provides a supercritical fluid adhesive obtained by compressing an adhesive composition comprising an adhesive prepolymer or an aqueous emulsion adhesive and carbon dioxide under high pressure. The agent is used.

Further, in order to achieve the second object, the present invention applies the above-mentioned supercritical fluid adhesive by spraying and adhering it in a step of adhering a sheet heating device including a surface mounting member, a heater and a heat insulating sheet. The present invention proposes a method for manufacturing a surface heating tool.

[0011]

The supercritical state of the supercritical fluid adhesive of the present invention is
It exists in a region beyond the critical point on the phase diagram and is effectively a liquid and gas phase. In this state, carbon dioxide has a significantly increased solubility in water or a solvent, and has a low viscosity and a high diffusivity. Therefore, when carbon dioxide is added to a high-concentration and high-viscosity adhesive composition to bring it to a supercritical state, a low-viscosity supercritical fluid adhesive having excellent coating properties is obtained. This property means that a general solvent type adhesive consists of an active solvent (good solvent) and a diluting solvent (poor solvent), and the diluting solvent occupies most of it due to its coatability, whereas it is a supercritical fluid adhesive. The agent can be used in a very small amount of solvent, and has a very effective property as, for example, a spray coating type adhesive. Carbon dioxide diffuses at the same time as spraying, a high-concentration coating film can be formed thinly on the substrate, and adhesion and drying can be performed in a short time.

Carbon dioxide has a critical point as low as 31 ° C. and 73 atm, is practical, and is almost non-polluting and non-flammable. Further, it has a high solubility in water and a solvent, and the effect of lowering the viscosity is extremely large.

As a material for the adhesive component contained in the supercritical fluid adhesive of the present invention, a conventional material such as an adhesive prepolymer or an adhesive emulsion proposed hitherto is applicable, but in any case. The amount of solvent or dispersant added is small, that is, the concentration of the adhesive component can be increased.

Further, when the supercritical fluid adhesive of the present invention is sprayed by using a spraying means, the sprayed supercritical fluid adhesive is easily atomized and easily becomes feathery, and especially fibers such as electric carpets are used. It is effective for adhering a large surface-shaped heating tool. Carbon dioxide is volatilized at the same time as spraying, and an adhesive with a high concentration of adhesive components is applied in a state where carbon dioxide has already escaped, and adhesion (drying / curing) can be performed in a short time.

[0015]

The present invention relates to a supercritical fluid adhesive obtained by pressure-compressing an adhesive composition containing an adhesive prepolymer or aqueous emulsion adhesive and carbon dioxide.

The present invention can be applied to any adhesive in principle, but an adhesive prepolymer or an aqueous emulsion adhesive can be used as a practical adhesive material that has sufficient characteristics and is highly pollution-free. Is preferably used.

As the adhesive prepolymer, there are polyurethane type, acrylic type, epoxy type, polyester type, silicone type and the like, which is selected according to the material to be adhered.
Moisture-curable polyurethane adhesives are the most suitable in terms of low pollution. There are various types of moisture-curable polyurethane adhesives, one of which is a water-reactive urethane prepolymer made by reacting an alkylene ether polyol with various isocyanates, which reacts with moisture in the air. And cure. Water or water containing a curing catalyst (amine, urea, etc.) can be simultaneously sprayed as a curing agent. In this case, a double-headed gun can be used for spraying. This polyurethane forms urea bonds, burette bonds, etc. and cures. In the case of the present invention, since the viscosity of the adhesive prepolymer can be made higher than usual because the viscosity can be lowered in a supercritical state, the adhesive curing rate can be increased, and at the same time, the monomer component is extremely small and does not volatilize, and thus excellent adhesion with low pollution Become an agent. Also, even if a solvent is required, a very small amount may be added.

On the other hand, as the emulsion adhesive, there are ethylene / acrylic copolymers, acrylic resins, vinyl urethane polymers, polymers having a vinyl acetate component, etc., which are selected according to the material to be adhered. Particularly, polymers having a vinyl acetate component such as polyvinyl acetate, ethylene / vinyl acetate copolymer, styrene / vinyl acetate copolymer, and vinyl chloride / vinyl acetate copolymer are suitable because they generally have strong adhesive force. .. Among them, the ethylene / vinyl acetate copolymer has excellent adhesive strength, and it is most practical that various adhesive properties can be designed by changing the compounding ratio of ethylene and vinyl acetate. A general emulsion adhesive requires a large amount of water (dispersion medium), but the supercritical fluid adhesive of the present invention does not require water to be added to the supercritical fluid in order to improve coatability, and water is evaporated. The heating energy used can be greatly reduced, and the drying speed can be made extremely high. These adhesive components may contain a small amount of active solvent.

No matter which adhesive component is used, the supercritical fluid adhesive of the present invention is a concentrated adhesive having a high solid content after the carbon dioxide in the supercritical fluid state is released, and has excellent adhesive properties. It is also applicable to adhesives made of higher molecular weight polymers.

The amount of supercritical carbon dioxide contained in the supercritical fluid adhesive of the present invention is determined by solubility, viscosity reducing effect, polymer concentration, spraying conditions, etc.
It is 0%. In the supercritical state, a single phase or a single dispersed phase can be formed. Also, the higher the temperature of the supercritical fluid adhesive, the lower the solubility of carbon dioxide.

Further, the supercritical fluid adhesive of the present invention may be added with a pigment, a filler, an antioxidant, a reaction catalyst, an adhesion promoter, and a plasticizer, if necessary.

The surface warming tool as referred to in the present invention is a heating appliance including a heater wire, such as an electric carpet, an electric blanket, an electric insulation haori, and a floor material. Among these surface heating devices, for example, for products requiring flexibility such as electric blankets or electric insulation haori, generally, the heater wire pre-coated with the supercritical fluid adhesive of the present invention is bonded to the mounting member or the heat insulating sheet. Although the method is adopted, when the supercritical fluid adhesive of the present invention is used, a strong adhesive strength can be obtained even with an extremely small coating amount as compared with the conventional one, and therefore the adhesive is coated over the entire surface mounting member or the heat insulating sheet. However, there are cases where flexibility can be demonstrated. However, it is preferable to apply the supercritical fluid adhesive of the present invention to, for example, an electric carpet or a flooring material, which is generally required to be coated with an adhesive on a large area and is required to be dried quickly, among the surface heating and warming tools. , Especially when it is required to bond fibrous material such as electric carpet.

Next, referring to FIG. 1, a process for manufacturing a sheet heating tool using the supercritical fluid adhesive of the present invention will be described by taking an electric carpet as an example. As shown in FIG. 1, the supercritical fluid adhesive 5 of the present invention is applied to the insulated heat insulating sheet 2 of the heater 3 by the spraying means 4 to bond the outer cloth 1 and the heat insulating sheet 2. .. Generally, a commercially available spray device can be used as the spraying means 4, but a heating type airless spray device is preferably used because cooling due to expansion of the supercritical fluid adhesive during spraying can be prevented. 6 is a pressurized tank of carbon dioxide, and 7 is a tank of thick adhesive. Carbon dioxide has a characteristic that the pressure and temperature in the supercritical state are within the operating range of a normal airless spray, and is industrially very preferable. Here, carbon dioxide is supplied from a gas cylinder, cryogenic container, tank,
A thick adhesive composed of an adhesive prepolymer or an aqueous emulsion adhesive is supplied from a pot, a tank or the like. The mixed supercritical fluid adhesive is supplied to the spray gun 4. The viscosity of this thick adhesive is about 500 to 10,000 centipoise. The spray gun can be manual, automatic or electrostatic. Supercritical fluid adhesive 5
The spray pressure is usually 80-150 kg / cm ² ,
The viscosity of the spray solution or supercritical fluid adhesive 5 is usually 5
It is about 0 centipoise or less. In order to prevent cooling due to expansion of the supercritical fluid adhesive 5 during spraying, the spray solution is generally heated to about 40 to 80 ° C.

In the case of a moisture-curable adhesive, the curing step after spray coating / adhesion of the adhesive of the present invention can be sufficiently cured with the moisture by using an insulating sheet containing a little moisture. On the other hand, in the case of an aqueous emulsion type adhesive, various heating methods such as hot plate, hot air and dielectric heating can be used as a drying step, but the supercritical fluid adhesive of the present invention has a high solid content and a high concentration. Since it forms a transparent adhesive coating,
The finishing drying process is easy. Specifically, if the surface cloth 1 and the heat insulating sheet 2 are sufficiently heated or dried before the adhesive is applied, the adhesive strength can be sufficiently increased only by the effect of water diffusion into the heat insulating sheet 2. ..

Since the present invention is a pressure-sensitive adhesive, some ingenuity is required when batch-changing the tank of the coating apparatus.
As a method of preventing hardening of the adhesive at the time of switching, there is a method of adding a solvent or a dispersion medium, for example.

In the method for manufacturing the surface heating tool of the present invention, in addition to the example shown in FIG. 1, the supercritical adhesive 5 may be applied to the surface mounting member 1, and the heater 3 is previously mounted on the surface mounting member 1. Needless to say, it may be wired, and the heater 3 and the heat insulating sheet 2 or the heater 3 and the mounting member 1 may be bonded.

Example 1 A concentrated aqueous emulsion adhesive of ethylene / vinyl acetate copolymer was placed in the tank 7 of FIG. Carbon dioxide was placed in the tank 6 and pressurized to maintain 100 atm to make a supercritical fluid. These were mixed as shown in FIG. 1 and led to a heating type airless spray 4. After the heat-insulating felt 2 in which the heater wire 3 and the temperature detection wire were wired was sufficiently dried, the adhesive 5 was spray-coated as shown in FIG. 1 by the heating airless spray 4 heated to 70 ° C. The napped surface cloth 1 was covered with hot air while applying hot air, and the adhesive was cured. The sprayed supercritical fluid adhesive 5 flew in a mist state and formed a thin and uniform adhesive thin film on the fibers of the non-woven fabric on the surface of the heat insulating sheet on which the heater was wired. Therefore, the amount of the adhesive was about 20 g / m ² which was extremely small compared with the conventional amount of about 150 g / m ² . The adhesive strength after leaving for 5 hours was as high as 10 kg / 2 cm width.

Example 2 A partially saponified ethylene / vinyl acetate / vinyl chloride copolymer concentrated aqueous emulsion adhesive was placed in the tank 7 of FIG. Carbon dioxide was placed in the tank 6 and pressurized to maintain 110 atm to be a supercritical fluid. These were mixed as shown in FIG. 1 and led to a heating type airless spray 4. After the heat-insulating felt 2 in which the heater wire 3 and the temperature detection wire were wired was sufficiently dried, the adhesive 5 was spray-coated as shown in FIG. 1 by the heating airless spray 4 heated to 70 ° C. The loop pile face cloth 1 was covered and adhered on this. 13MH as a drying process
It was passed through a high frequency dielectric heating and drying oven of z at 30 cm / sec to be dried and cured. The amount of adhesive was about 25 g / m ² , which is extremely smaller than the conventional amount of about 150 g / m ² . Also, the adhesive strength after standing for 5 hours was as high as 12 kg / 2 cm width.

Example 3 A moisture-curable urethane prepolymer adhesive was placed in the tank 7 shown in FIG. Carbon dioxide was placed in the tank 6 and pressurized to 120 atm to make it a supercritical fluid. These were mixed as shown in FIG. 1 and led to a heating type airless spray 4. The heat-insulating felt 2 in which the heater wire 3 and the temperature detection wire were wired was slightly moistened, and then the adhesive 5 was spray-coated as shown in FIG. 1 by the heating airless spray 4 heated to 60 ° C. Pile top cloth 1 on this
And was adhesively cured under a pressure press for 1 minute. The sprayed supercritical fluid adhesive flew in a mist state and formed a thin and uniform adhesive thin film on the fibers of the non-woven fabric on the surface of the heat insulating sheet on which the heater was wired. Therefore, the amount of the adhesive was 30 g / m ² which was extremely small compared with the conventional amount of 150 g / m ² . The adhesive strength after leaving for 5 hours was as high as 8 kg / 2 cm width.

In each of the above embodiments, only the example in which the heater is preliminarily wired on the heat insulating sheet is shown, but the method for manufacturing the planar heating tool of the present invention is not limited to this example.
It is natural that the supercritical fluid adhesive of the present invention may be applied to either or both of the heater and the mounting member, the heater and the heat insulating sheet, or the combination of the surface member and the heat insulating sheet. .. In addition, in each of the above-mentioned examples, an example of an electric carpet was shown, but the same effect was obtained with a floor material for floor heating, and the same effect was obtained with an electric blanket or the like.

[0031]

As described above, the present invention is a supercritical fluid adhesive obtained by compressing an adhesive composition comprising an adhesive prepolymer or an aqueous emulsion adhesive and carbon dioxide under high pressure. The present invention provides a novel supercritical fluid adhesive that does not need to be dried immediately and is pollution-free. Further, the present invention provides a method for producing a non-polluting surface warming tool which has high production efficiency, is inexpensive, and uses this supercritical fluid adhesive. The present invention provides such an inexpensive adhesive and can realize an extremely inexpensive and highly efficient bonding process with simple coating equipment. As described above, the present invention has great industrial value.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a method for manufacturing a planar heating tool according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Covering member 2 Heat insulating sheet 3 Heater 4 Spraying means 5 Supercritical fluid adhesive 6 Carbon dioxide pressure tank 7 Thick adhesive tank

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 14, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

[0015]

EXAMPLES The present invention is directed to adhesive prepolymer or an aqueous emulsion adhesive, a supercritical fluid adhesive an adhesive composition containing a carbon dioxide high pressure compressor.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

The surface warming tool as referred to in the present invention is a heating appliance including a heater wire, such as an electric carpet, an electric blanket, an electric insulation haori, and a floor material. Among these surface heating devices, for example, for products requiring flexibility such as electric blankets or electric insulation haori, generally, the heater wire pre-coated with the supercritical fluid adhesive of the present invention is bonded to the mounting member or the heat insulating sheet. Although the method is adopted, when the supercritical fluid adhesive of the present invention is used, a strong adhesive strength can be obtained even with an extremely small coating amount as compared with the conventional one, and therefore the adhesive is coated over the entire surface mounting member or the heat insulating sheet. However, there are cases where flexibility can be demonstrated. However, it is preferable to apply the supercritical fluid adhesive of the present invention to, for example, an electric carpet or a flooring material, which is generally required to be coated with an adhesive on a large area and is required to be dried quickly, among the surface heating and warming tools. , Especially when it is required to bond fibrous material such as electric carpet. Also, as a surface material for electric carpets
Is, for example, a needle punch felt or French pad.
There is a smooth surface cloth such as il, but for example, cut pie
Of loop, pile or jaggy
The supercritical fluid adhesive of the present invention is suitable for high napped surface adhesion
Is. On the other hand, the heat insulating sheet is, for example, a urethane foil.
Various sheets such as foam, felt or non-woven fabric are listed.
You can In the case of such a breathable adhesive sheet
From the spray gun when applying the supercritical fluid adhesive
Since carbon dioxide is vaporized, the air intake means should be installed behind the heat insulating sheet.
It is installed on the surface (sheet support side), and if it inhales by it
Prevents the spray particles from volatilizing and simplifies spraying.
The adhesive can be efficiently applied to the sheet surface by a single means. It
In addition, this prevents the pollution of the environment by spraying as much as possible.
You can stop it.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C09J 131/04 JCH 6904-4J JCW 6904-4J JCY 6904-4J 175/04 JEZ 8620-4J H05B 3 / 20 338

Claims (6)

[Claims] 1. A supercritical fluid adhesive characterized in that an adhesive composition containing at least one of an adhesive prepolymer or an aqueous emulsion adhesive and carbon dioxide is compressed under high pressure. 2. The supercritical fluid adhesive according to claim 1, wherein the adhesive prepolymer is a moisture-curable urethane adhesive. 3. The supercritical fluid adhesive according to claim 1, wherein the aqueous emulsion adhesive is mainly composed of a polymer having a vinyl acetate component. 4. The supercritical fluid adhesive according to claim 3, wherein the polymer having a vinyl acetate component is an ethylene / vinyl acetate copolymer. 5. In a process of manufacturing a heat collecting tool including a cover member, a heater and a heat insulating sheet, one surface of the cover member and the heater, and one surface of the heat insulating sheet and the heater, Hi
Supercritical by spraying means to at least one or both of the cover member and the heat insulating sheet in which the heater is wired on one surface or the heat insulating sheet and the cover member in which the heater is wired to one surface. A method of manufacturing a planar heating tool using a supercritical fluid adhesive, which comprises a step of coating and adhering a fluid adhesive. 6. The method for manufacturing a planar warming tool using a supercritical fluid adhesive according to claim 5, wherein the spraying means is a heating type airless spray.