JPH06270303A - Manufacture of composite panel - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for producing a composite panel having excellent workability by using an aqueous adhesive having excellent heat resistance and adhesive strength. [Structure] An aqueous adhesive containing a polyurethane resin and polyisocyanate is applied to a honeycomb core material or a base material, and after drying, the application surface of the adhesive is brought into contact with the adhered surface of the honeycomb core material or the base material, Composite panel manufacturing method characterized by thermocompression bonding

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a composite panel having a sandwich structure used for interiors and exteriors of buildings, especially doors.

[0002]

2. Description of the Related Art A sandwich type composite panel constructed by sandwiching a honeycomb-shaped core (honeycomb core) between two base materials and assembling the composite core generally has high strength to weight ratio. It is widely used for furniture, building materials, vehicles, aircraft, etc. because of its rigidity.

Conventionally, as an adhesive used for manufacturing a composite panel, a chloroprene-based solvent-based adhesive or a urethane resin-based solvent-based adhesive containing a polyisocyanate has excellent flame resistance and chemical resistance. Etc. were used. (JP-A 61-127341)

When a chloroprene-based solvent-based adhesive is conventionally used in the production of composite panels, it is necessary to apply it to both the honeycomb core material and the base material, that is, to apply it to both sides, because the adhesive strength is weak. Workability was extremely poor in manufacturing the panel, and heat resistance was not sufficiently satisfactory. On the other hand, when a urethane resin-based solvent-based adhesive containing polyisocyanate was used, one-side coating was possible.

[0005]

However, since all such adhesives are solvent-based, there is a risk that an organic solvent will volatilize during application and drying of the adhesive, causing a fire. In addition, there was a problem of environmental pollution in terms of hygiene and pollution.

For this reason, there is a strong demand for solvent-free adhesives, and the use of water-based adhesives in the production of composite panels has been investigated. An example of such an adhesive is a water-based chloroprene-based adhesive, but like the chloroprene-based solvent-based adhesive, double-sided coating is always required and heat resistance is not satisfactory.

The present invention is intended to solve the above-mentioned problems, and an object thereof is to provide a method for producing a composite panel using an adhesive having excellent heat resistance and workability without causing environmental pollution. To do.

[0008]

A method for manufacturing a composite panel according to the present invention comprises a honeycomb core material or a base material containing an aqueous adhesive containing a polyurethane resin and a polyisocyanate,
After coating and drying, the above-mentioned object is achieved by bringing the coated surface of the adhesive into contact with the adhered surface of the honeycomb core material or the base material and heating and pressure bonding.

The above water-based adhesive is generally produced by mixing a polyurethane resin and polyisocyanate immediately before use. After the water-based adhesive is applied to the honeycomb core material and / or the base material, the water content is evaporated by heating. Usually, the back surface of the base material is brought into contact with the application surface of the water-based adhesive applied to the honeycomb core material, and pressure bonding is performed using a roll press, a flat press or the like. The crimping advantageously uses a flat press in order to sufficiently heat and reactivate the adhesive layer. The temperature and pressure at the time of pressure bonding depend on the type and strength of the base material and honeycomb core material,
The temperature is generally selected from room temperature to 110 ° C., preferably 60 to 80 ° C., although it is appropriately selected depending on the required dimensional accuracy.

The above polyurethane resin is a polyurethane resin emulsion in which a urethane resin having sulfonic acid, carboxyl group, hydroxyl group or the like introduced into the main chain or side chain is dispersed in water.

The polyurethane resin emulsion used in the present invention preferably has a softening point in the range of 30 to 110 ° C. When the softening point is less than 30 ° C, the initial cohesive force of the obtained water-based adhesive is reduced, and when the softening point is 110 ° C or more, the reactivation temperature is too high, and the honeycomb core material and the base material are damaged. There is a risk of

The above polyurethane resin emulsion contains
A tackifying resin may be contained in order to improve the adhesion to the honeycomb core material and the substrate, and specific examples of the tackifying resin include terpene-modified phenol resin, rosin-modified phenol resin, rosin, rosin ester, and petroleum. Examples of the resin include rosin and rosin ester.

The polyurethane resin emulsion may contain a thickener for adjusting the viscosity. Specific examples of the thickener include polyvinyl alcohol,
Urethane-based, acrylic-based, and cellulose-based are used, but urethane-based thickeners are preferably used.

The polyisocyanate used in the present invention is a water-dispersible aliphatic isocyanate used as a main component of a curing agent. As a representative example, a trimer of an aliphatic isocyanate is modified so that it can be dispersed in water.

The mixing amount of the above-mentioned curing agent containing polyisocyanate as a main component in the water-based adhesive is not specified, but is generally 1 to 20 parts by weight with respect to 100 parts by weight of the polyurethane resin emulsion. .

The substrate used in the present invention includes
Examples thereof include, but are not limited to, a synthetic resin plate, a synthetic rubber plate, a decorative plate, a synthetic wood, a metal plate made of iron or aluminum, particularly zinc, or a coated metal plate, and a laminated plate thereof.

Examples of the honeycomb core material used in the present invention include synthetic resin-impregnated paper such as phenol resin, non-impregnated paper, and aluminum foil, but are not particularly limited.

The above water-based adhesive is usually applied only to the substrate by a method such as an air spray, a curtain flow coater, a roll coater, a knife coater, etc., but in some cases, if necessary, the honeycomb core material and the substrate may be coated. It may be applied on both sides or only on the honeycomb core material.

[0019]

[Function] Polyurethane resin has a flexible film originally,
It has excellent strength, heat resistance, durability, and adhesion to base materials. However, if a sulfonic acid, a carboxyl group, a hydroxyl group or the like is introduced into the side chain or main chain of the polyurethane resin in order to make it water-soluble, it is unavoidable that the characteristics of the polyurethane resin are impaired. Therefore, by containing polyisocyanate in the polyurethane resin as a curing agent, the film of the polyurethane resin was strengthened and single-side coating was made possible.

[0020]

EXAMPLES Examples and comparative examples of the present invention will be shown below. Example 1 An emulsion composed of a water-soluble urethane resin having a softening point of 35 ° C. (trade name “Sampren UXA3004” manufactured by Sanyo Kasei Co., Ltd.
A ") 100 parts by weight and a mixture of 100 parts by weight of a urethane thickener (trade name" Bortigel L-75 "manufactured by Sumitomo Bayer Urethane Co., Ltd.)" and a water-dispersible compound obtained by modifying an aliphatic isocyanate trimer. 3 parts by weight of a curing agent (trade name “Esdyne UX-W” manufactured by Sekisui Chemical Co., Ltd.) was added to obtain a water-based adhesive. This water-based adhesive has a thickness of 0.
Apply a roll coater on both sides of a honeycomb core material made of paper 2 mm in height and 4 cm in height to a thickness of about 300 μm.
After drying for 3 minutes at 0 ° C, epoxy coated boards (thickness 2
mm), and pressure-bonded for 2 minutes under a press condition of 60 ° C. and 2 kg / cm ² . Then, it was left to stand in a normal temperature atmosphere for 24 hours to obtain a composite panel having a sandwich structure in which the base material and the honeycomb core material were firmly bonded. The tensile strength of the obtained composite panel was measured, and the fracture state was observed. The results are shown in Table 1.

(1) Tensile strength Using the obtained composite panel as a test piece, 20 ° C. or 80 ° C.
The plane tensile strength was measured at 50 mm / min in the direction perpendicular to the bonded surface under the atmosphere of.

(2) State of Breakage The portion where the test piece used for tensile strength was broken was visually determined. The judgment criteria were: core material destruction- ○, adhesive layer cohesive failure- △, adhesive layer-base material interface failure- ×.

Example 2 Emulsion composed of water-soluble urethane resin having a softening point of 40 ° C. (trade name “HYDRAN H” manufactured by Dainippon Ink and Chemicals, Inc.)
W337 ")) A composite panel having a sandwich structure was manufactured in the same manner as in Example 1 except that 100 parts by weight was used. The results of tensile strength and fracture state of the obtained composite panel are shown in Table 1.

Example 3 Emulsion composed of water-soluble urethane resin having a softening point of 35 ° C. (trade name “Sampren UXA3004” manufactured by Sanyo Kasei Co., Ltd.)
A ") 100 parts by weight and a rosin ester-based tackifying resin (SN-754 manufactured by San Nopco Co.) are mixed, and 100 parts by weight of this mixture is formed by modifying a trimer of an aliphatic isocyanate to be water-dispersible. A water-based adhesive was obtained by adding 5 parts by weight of a curing agent (trade name “Esdyne UX-W” manufactured by Sekisui Chemical Co., Ltd.). This water-based adhesive was used in Example 1.
A composite panel having a sandwich structure was manufactured in the same manner as in. The results of tensile strength and fracture state of the obtained composite panel are shown in Table 1.

[0025]Comparative Example 1 Chloroprene-based solvent-based adhesive (Sekisui Chemical Co., Ltd. trade name
"Esdyne 276FS") on epoxy coated board (thickness
2mm) with a roll coater to a thickness of about 300μm
And dried at 50 ° C. for 5 minutes and then used in Example 1.
EPO coated with adhesive from both sides of similar honeycomb core material
It is sandwiched by a sheet of kisshi coating, 60 ℃, 2kg / cm ²Press Article
It was crimped for 2 minutes. After that, in normal temperature atmosphere for 24 hours
After standing, a composite panel having a sandwich structure was obtained. Obtained
The tensile strength of the composite panel
Shown in 1.

Comparative Example 2 Urethane resin-based solvent type adhesive containing polyisocyanate (Sekisui Chemical Co., Ltd. trade name "ESDINE UX-10")
100 parts by weight and 50 parts by weight of methylenebis P-phenylene diisocyanate (MDI) as a curing agent were mixed to obtain an adhesive. This adhesive was applied to an epoxy coated plate with a roll coater to a thickness of about 300 μm, dried at 50 ° C. for 5 minutes, and the same honeycomb core material as that used in Example 1 was coated with epoxy coated plates from both sides. Sandwich, 60 ℃, 2kg
It was pressure-bonded for 2 minutes under a pressing condition of / cm ² . Then, it was left to stand in a normal temperature atmosphere for 24 hours to obtain a composite panel having a sandwich structure. The tensile strength of the obtained composite panel and the result of the fracture state are shown in Table 1.

Comparative Example 3 Urethane resin solvent type adhesive containing polyisocyanate (trade name "ESDINE UX-10" manufactured by Sekisui Chemical Co., Ltd.)
100 parts by weight and 50 parts by weight of methylenebis P-phenylene diisocyanate (MDI) as a curing agent were mixed to obtain an adhesive. This adhesive was applied to an epoxy coated plate with a roll coater to a thickness of about 300 μm, dried at 50 ° C. for 5 minutes, and the same honeycomb core material as that used in Example 1 was coated with epoxy coated plates from both sides. Sandwich, 60 ℃, 2kg
It was pressure-bonded for 2 minutes under a pressing condition of / cm ² . Then, it was left to stand in a normal temperature atmosphere for 24 hours to obtain a composite panel having a sandwich structure. The tensile strength of the obtained composite panel and the result of the fracture state are shown in Table 1.

Comparative Example 4 As a water-based adhesive, a chloroprene-based emulsion adhesive (trade name "ESDINE 127K" manufactured by Sekisui Chemical Co., Ltd.)
50 g / cm ^{2 on} both sides of a honeycomb core material similar to that used in Example 1, and about 300 μm on an epoxy coated plate.
To the thickness of 60 ° C and dried for 3 minutes at 60 ° C, sandwich the honeycomb core material from both sides with epoxy coated plates,
It was pressure-bonded for 2 minutes under a pressing condition of / cm ² . Then, it was left to stand in a normal temperature atmosphere for 24 hours to obtain a composite panel having a sandwich structure. The tensile strength of the obtained composite panel and the result of the fracture state are shown in Table 1.

[0029]

[Table 1]

As is clear from Table 1, in the composite panel obtained by the method for producing a composite panel of the present invention, the composite panel using the solvent-based adhesives of Comparative Examples 2 and 3 while using the water-based adhesive was used. Adhesive strength equivalent to is obtained.

[0031]

As described above, according to the method for producing a composite panel of the present invention, substantially sufficient adhesive strength is exhibited even by applying one side of a water-based adhesive containing a polyurethane resin and a polyisocyanate to a honeycomb core material or a base material. Therefore, the workability can be improved. Further, since the water-based adhesive used in the present invention is solvent-free, it does not pollute the environment and has excellent heat resistance and adhesive strength.

Claims (1)

[Claims] 1. A honeycomb core material or a base material is coated with an aqueous adhesive containing a polyurethane resin and a polyisocyanate, dried, and then the coated surface of the adhesive is brought into contact with the adhered surface of the honeycomb core material or the base material. Composite panel manufacturing method characterized by thermocompression bonding