JPH11140419A - Reactive hot melt adhesive agent and adhesion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesion technique without possibility of environmental pollution with a short adhering time and costly advantageous. SOLUTION: This reactive hot melt adhesive agent mainly comprises a urethane prepolymer containing 0.5-10.0 wt.% of isocyanate group in a principal chain molecule of a polyol polymer and having 500-10,000 molecular weight. Preferably, the principal chain molecule is arbitrarily selected from a polyether polyol, a polyester polyol and a polyurethane polyol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for bonding a heat insulating material to a metal roof. In particular, the present invention relates to a technique for bonding a heat insulating material such as glass fiber, synthetic resin fiber, plastic foam, or inorganic foam to the back surface of a metal roof for the purpose of heat insulation and dew condensation prevention.

[0002]

2. Description of the Related Art Conventionally, in order to bond a heat insulating material to a metal roof, a rubber-based solvent-based adhesive is applied to the metal roof by roll coating or spray coating, and is made to be in a semi-dry state at room temperature or in a drying oven. In addition, a method of attaching a heat insulating material to this is taken. Conventionally, the rubber-based solvent-based adhesive used in this case is prepared by dissolving chloroprene synthetic rubber, styrene, butadiene copolymer rubber together with phenol resin, petroleum resin, rubber compounding chemicals, etc. in an organic solvent such as toluene or xylene. Being manufactured.

[0003] When bonding a heat insulating material using the above-mentioned rubber-based solvent-based adhesive, an organic solvent evaporates into the air, so that measures for environmental protection and fire prevention are desired. ing.

[0004] On the other hand, another method of bonding a heat insulating material to a metal roof is to apply a heat-reactive solvent-based or water-dispersed (latex, emulsion) adhesive to the metal roof in advance, A method is also known in which the adhesive applied to the roof is heated until the adhesive softens and becomes viscous, and the heat insulating material is bonded.

[0005]

However, in the conventional rubber-based solvent-based adhesive described above, environmental pollution due to the evaporation of the solvent becomes a problem as described above, and a step of evaporating the organic solvent is required. There is also a problem that it takes time to work. On the other hand, in the case of the above-mentioned water-dispersed adhesive, there are problems in that it takes a long time to evaporate water, and high energy is required when a drying oven is used for volatilization. Furthermore, when bonding by heat reactivation, the equipment investment cost is high and uneconomical.

Accordingly, the present invention provides a bonding technique which is free from environmental pollution due to volatilization of an organic solvent, has a short bonding time and is advantageous in cost, for example, a technique for bonding a heat insulating material to a metal roof. The task is to

[0007]

In order to solve the environmental pollution caused by the organic solvent, a bonding technique which does not use an adhesive containing an organic solvent is desired. Such techniques include:
Adhesion with an adhesive tape, a technique using an aqueous adhesive such as an emulsion type or a latex type, or a technique using a non-solvent chemically reactive adhesive are exemplified. However, adhesion with an adhesive tape has many problems, such as time-consuming release paper processing and work. A water-based adhesive such as an emulsion type or a latex type requires a long time for drying water, and requires investment in equipment such as a drying oven. Further, a solventless chemically reactive adhesive is not practical because it takes a long time to cure or has a low initial adhesive strength until it is cured.

[0008] On the other hand, the above-mentioned method of bonding by thermal reactivation has the advantage that it does not lead to environmental pollution since it does not require the step of evaporating the organic solvent, although it requires capital investment.

Under the above background, the present inventors have:
We conceived of applying a heat-reactive adhesive from the beginning by melting it with heat, and found an adhesive technique using a hot-melt adhesive. At this time, the time required for the hot-melt adhesive to melt from heat, apply, cool, and harden is short,
In order to bond a wide area material such as a heat insulating material, a sufficient adhesion time cannot be obtained as it is. Therefore, in the present invention, as a method of extending the adhesion time, utilizing the fact that the above-mentioned chemically reactive adhesive is weakly adhesive until it is cured, a combination of the hot melt adhesive and the chemical reactivity is used. By doing so, a sufficient adhesion time is obtained.

That is, according to the present invention, the polyol polymer has 0.5% to 10.0% by weight of isocyanate groups in the main chain molecule and has a molecular weight of 500 to 1000%.
A reactive hot melt adhesive based on a urethane prepolymer of 0 is provided. Preferably, the main chain molecule is arbitrarily selected from a polyether polyol, a polyester polyol, and a polyurethane polyol.

Further, the present invention relates to a method for bonding a metal roof and a heat insulating material, wherein 0.5% by weight is contained in a main chain molecule having a polyol group.
A reactive hot-melt adhesive mainly containing a urethane prepolymer having a molecular weight of 500 to 10,000 having an isocyanate group of about 10.0% by weight and a metal roof and a heat insulating material in a state of blocking moisture. A bonding method comprising a step of applying to at least one of the above.

The present invention will be described in more detail as follows. As a raw material of the above reactive hot melt adhesive, a polyol polymer such as a polyether polyol, a polyester polyol and a polyurethane polyol is used as a main chain molecule, and 0.5% to 10% by weight thereof.
Having a molecular weight of 500 to 500% with 0% by weight of isocyanate groups
10,000 urethane prepolymers were selected. The urethane prepolymer has good heat stability, while the isocyanate group easily reacts with dew condensation water around the surface or moisture on the surface of the adherend during cooling to be cured.

Here, the curing reaction mechanism of the reactive hot melt adhesive is as follows.

[0014]

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As the main chain molecule, polyether, polyester and polyurethane are excellent in heat stability and adhesion to materials (metal, heat insulating material). Since the reactive hot melt adhesive reacts with moisture on the surface of the adherend in the air and cures, it is preferable to block moisture during heating and melting. Therefore, the reactive hot melt adhesive is
Applicator that shuts out moisture, for example, IT
It is preferable to bond the metal roof insulation material in combination with an applicator manufactured by W Dynatech Co., Ltd.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited by these embodiments. In the present embodiment, a chemical kneader blender that can be heated to 150 ° C. at the internal temperature is used.

Table 1 shows the compositions of the hot melt adhesive samples 1 to 9 manufactured in this embodiment.

[0018]

[Table 1]

As shown in Table 1, Samples 1 to 9 each have polyether polyol, polyester polyol, and polyurethane polyol as main chain molecules. The content of the isocyanate group in these samples was 0.5% by weight to 10% by weight, and the average molecular weight was 500 to 18,000.

In producing Samples 1 to 9, dehydrated polyether polyol, polyester polyol or polyurethane polyol was added, and heated and stirred at 80 to 100 ° C. while passing nitrogen gas. After heating and stirring for about 10 minutes, the diisocyanate compound is added little by little, and the mixture is kept in a nitrogen stream at 80 to 100 ° C. for about 30 minutes.
And heating and stirring were continued. Thereafter, a dehydrated inorganic filler was added. The composition thus obtained was filled in a metal pail can at the time of heating, filled with nitrogen gas and closed with a lid.

Using the adhesive obtained as described above, the steel sheet was bonded to polyethylene foam, and the steel sheet was bonded to glass wool. And normal 48
The peel strength after the passage of time was measured. In addition, heat aging (7
Tests were also conducted with respect to water resistance (soaking for 48 hours at 0 ° C.) and heat resistance (80 ° C.). The test method is based on the JIS test method. Table 2 shows the results.

[0022]

[Table 2]

As shown in Table 2, in all of Test Examples 1 to 9, when adhesion to polyethylene foam was performed, 1.7 to 1.9 (N / 25 m
m), a satisfactory peel strength of 1.9 to 2.3 (N / 25 mm) was obtained in the normal state when bonding with glass wool was performed. Further, it was excellent in heat aging resistance and water resistance, and there was not much change in peel strength.

Since the reactive hot melt adhesive according to the present invention reacts with the moisture in the air or on the surface of the adherend differently from the conventional one, it is preferable to block the moisture. Therefore, it is preferable to combine with a dedicated applicator, for example, an applicator manufactured by ITW Dynatech Co., Ltd. to block moisture and perform adhesion.

[0025]

As described above, according to the present invention,
The bonding can be performed using a reactive hot melt adhesive without using an organic solvent that has an adverse effect on the environment.
In particular, it is possible to adhere a heat insulating material to the back surface of the metal roof for the purpose of preventing heat insulation.

Claims (3)

[Claims] 1. The method according to claim 1, wherein said polyol polymer has a molecular weight of 0.
Having 5% to 10.0% by weight of isocyanate groups,
A reactive hot melt adhesive containing a urethane prepolymer having a molecular weight of 500 to 10,000 as a main component. 2. The method according to claim 2, wherein the main chain molecule is arbitrarily selected from a polyether polyol, a polyester polyol, and a polyurethane polyol.
The reactive hot melt adhesive according to the above. 3. A method for bonding a metal roof and a heat insulating material, wherein 0.5% by weight to 1% by weight in a main chain molecule having a polyol group.
A reactive hot melt adhesive containing 0.0% by weight of isocyanate groups and having a molecular weight of 500 to 10,000 and containing a urethane prepolymer as a main component is used to remove a moisture from the metal roof and the heat insulating material. A bonding method comprising a step of applying to at least one side.