JPS6339419B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for bonding a honeycomb sandwich structure panel, and more specifically, a novel urethane adhesive is applied to both sides of a honeycomb core core material to bond a surface plate. Concerning the manufacturing method of Sanderutsch structural panels.

Honeycomb sandwich structure panels are lightweight, have high strength, excellent dimensional stability, and have heat insulation and soundproofing functions, so they are widely used for furniture, room partition panels, blackboards, etc. Conventionally, such honeycomb sandwich structure panels have generally been manufactured by using a honeycomb core as a core material and bonding various surface plates (painted or surface-treated steel plates, plastic plates, aluminum alloy plates, etc.) to this with adhesives. ing. In such adhesive processing, epoxy resin adhesives and chloroprene rubber solution adhesives are used, but usually in order to increase the adhesive strength between the honeycomb core and the top plate, the adhesive is applied to the entire back surface of the top plate and as needed. Accordingly, it could not be put into practical use unless coated on both sides of the honeycomb core. As a result, even though the effective bonding area is the linear bonding area of the honeycomb core, the entire back surface of the surface plate is forced to be coated, so the use of adhesive is unavoidable. Further, the following problems arise due to the adhesive. In other words, in the case of epoxy resin adhesives, the main ingredient and curing agent must be measured and mixed, and the cured material is not flexible enough to cause peeling due to impact, etc., and the edges may There were problems such as peeling of the entire surface from areas with poor adhesion.

In addition, in the case of a chloroprene rubber solution type adhesive, there were problems such as the safety and health issues of organic solvents and fire safety issues, and the need to apply the adhesive to both the honeycomb core and the surface plate.

Furthermore, in order to solve the problem of applying both adhesives to the entire surface of the surface plate, attempts have been made to increase their viscosity to give them thixotropic properties and apply them only to the honeycomb core side. The current situation is that it has not been put into practical use due to the above problems. Moreover, in response to the demand that the surface plate must also be adhered to the peripheral edge of the honeycomb sandwich structure panel, a so-called bento box-shaped structure in which the peripheral edge is pre-molded on one side of the surface plate has recently been developed. Surface plates are being adopted, and in this case it is not possible to automate the coating work using a roll coater, and in the end the coating must be done manually using a brush or roller brush, which poses problems in terms of labor saving. It was hot.

Therefore, the present inventors conducted intensive research to solve the above problems, and found that if a special moisture-curing liquid-type urethane adhesive was used as the adhesive,
By applying roll coating only to both sides of the honeycomb core side and overlapping the surface plate, it is possible to create the desired honeycomb sandwich structure panel without applying it to the surface plate, while reducing the amount of adhesive used and the work required. The present inventors have discovered that the process can be streamlined and speeded up, and have completed the present invention.

That is, the present invention uses a honeycomb core as a core material,
To manufacture a sandwich structure panel by bonding a face plate to this, a moisture-curable one-component urethane adhesive with a viscosity of 8,000 to 18,000 cps and a thixotropy coefficient of 1.2 to 3.5 (described later) is applied to the front and back surfaces of the honeycomb core using a roll coater. The present invention provides an adhesive processing method for a honeycomb sandwich structure panel, which is characterized by coating the honeycomb core, and then superimposing and bonding face plates on both sides of the honeycomb core.

The moisture-curable one-component urethane adhesive used in the present invention (hereinafter referred to as the adhesive of the present invention) contains an excessive amount of polyisocyanate compounds (diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, cyclohexylmethane diisocyanate, tolylene diisocyanate, etc.). isocyanate, hexamethylene diisocyanate, xylene diisocyanate, p-phenylene diisocyanate, etc.) and 1
Polyols (polyoxyalkylene ether polyols, polyester polyols,
Urethane obtained by appropriately selecting and using one or more types of acrylic polyols, butadiene polyols, castor oil derivatives, etc. to achieve the desired physical properties and viscosity, and reacting them under heating at 60 to 100°C for several hours. The main component is a prepolymer, and if necessary, conventional additives such as plasticizers (dioctyl phthalate, butylbenzyl phthalate, dinonyl phthalate, diethylene glycol dibenzoate, alkyl polycyclic aromatic hydrocarbons, chlorinated paraffin, etc.) are added. ), small amounts of solvents (toluene, xylene, esters, ketones,
ethers, etc.), fillers (calcium carbonate, clay, talc, etc.), pigments, catalysts (dibutyltin dilaurate, dibutyltin dioctate, tin octoate, dioctyltin dilaurate, dimethylcyclohexylamine, tributylamine,
triethylenediamine, dimethylbenzylamine, etc.), thixotropic agents (finely powdered silica,
It is composed of a system containing hydrogenated castor oil, higher monohydric alcohol, etc.) and adhesion agents (silane compounds, etc.). In producing the above urethane prepolymer, a polyisocyanate compound and a polyol are
The reaction is carried out at a ratio of NCO groups/OH groups of greater than 2.0, and the active NCO group content in the urethane prepolymer usually obtained is set to 2.0 to 13.0% by weight. In addition, when preparing the adhesive of the present invention, the blending ratio of additives is usually 100% of the urethane prepolymer.
(parts by weight, the same applies hereinafter), 20 to 50 parts (preferably 30 to 40 parts) of liquid components such as plasticizers and solvents,
The filler may be selected in an amount of 100 to 150 parts, and the amount of the catalyst, thixotropic agent, adhesion agent, etc. may be selected within an appropriate range.

The adhesive of the present invention prepared in this way usually has a viscosity range of 8,000 to 18,000 cps and has some thixotropy.
For example, if the thixotropic coefficient [the value obtained by dividing the viscosity at a shear rate of 2 rpm by the viscosity at 20 rpm in a B-type viscometer] is in the range of 1.2 to 3.5, and this is applied to the linear bonded part of the honeycomb core. Also,
The adhesive of the present invention flows less and the difference in adhesive strength between the front surface and the back surface is negligibly small, making it possible to obtain the desired adhesive strength. In addition, the adhesive of the present invention is a one-component type that cures through the reaction of its active NCO groups with moisture in the air, so there is no need to mix a main ingredient and a curing agent like in conventional epoxy resin adhesives. Work can be streamlined. Furthermore, the cured product has an elongation of 100% or more and a tensile strength of 20Kg/cm ² or more in the dumbbell physical property test specified in the vulcanized rubber physical testing method JISK6301, so it can be peeled off by impact like epoxy resin adhesives. There's nothing to do.

Below, based on the attached drawings, the adhesive processing method for the honeycomb sandwich structure panel according to the present invention will be explained.
Explain in detail.

A honeycomb sandwich structure panel obtained by the method of the present invention is shown, for example, in FIG. Surface plate 3a, 3
b are stacked and glued together.

In the method of the present invention, for example, as shown in FIG. 2, adhesives 2a and 2b are first applied to the front and back surfaces of a honeycomb core 1 cut into a predetermined shape using rolls 4a, 5a, 4b, and 5b of a roll coater, usually in an amount of 100 to 200 g, respectively. /
Apply at the same time with a coating amount of m ² . Adhesive 2a, 2
As shown in Fig. 1, since adhesive is applied only to the linear portion of the honeycomb core 1, waste of adhesive is clearly reduced compared to the case where the adhesive is applied to the entire surface plate as in the conventional method, and the effective adhesive surface is increased. Can be applied only to In this way, the adhesive can be applied to the front and back surfaces of the honeycomb core almost simultaneously, which saves labor in applying the adhesive. Next, if a surface plate (not shown) is superimposed on the adhesive layers 2a and 2b on the front and back surfaces of the honeycomb core 1 and compression bonded under normal conditions, the
The curing is completed within a few days and the desired honeycomb sandwich structure panel is completed.

According to the method of the present invention having the above configuration, the adhesive of the present invention used has a viscosity and thixotropy within the above-mentioned range, and the adhesive of the present invention on the upper surface applied to the honeycomb linear portion flows. There is almost no decrease in adhesive strength due to insufficient adhesive, and good adhesive strength can be obtained on both the front and back sides. Furthermore, even if the surface plate is in the shape of a bento box with bent peripheral edges, the adhesive of the present invention can be applied to the honeycomb core, so there is no need to separately adhere the peripheral edges after creating the target panel. This leads to significant labor savings in bonding work. The method of the present invention has many advantages, such as adequate fluidity of the applied adhesive, which eliminates adhesive shortages, and eliminates the need to apply adhesive to both the honeycomb core and the top plate.

Next, the present invention will be specifically explained with reference to Examples.

Production example 1 (Preparation of adhesive) 800 g of polyethylene-propylene ether diol (molecular weight 2000), 200 g of polyester polyol (number of functional groups 2.0, molecular weight 1500) and DOP500
g and 400 g of diphenylmethane diisocyanate.
The mixture was reacted at 80°C for 2 hours with stirring to obtain a urethane prepolymer (viscosity 9000 cps, active NCO group content 4.6% by weight). Calcium carbonate, which has been heated and dried in advance, is added to the entire amount of the urethane prepolymer.
2000g and 50g of finely powdered anhydrous silica are mixed and kneaded. Next, 200 g of toluene and 1.2 g of dibutyltin dilaurate are blended and mixed to prepare a moisture-curable one-component urethane adhesive (viscosity 12000 cps, thixotropy coefficient 2.5). When this adhesive was applied to a thickness of 2 mm on a glass plate and cured for 7 days, it had an elongation of 300% and a tensile strength of 30 Kg/cm ² in terms of dumbbell physical properties.

Example 1 (Adhesive processing of honeycomb sandwich structure panel) A honeycomb core (thickness 20 mm, width 600
mm, length 900 mm) and transferred, and the adhesive of Production Example 1 was applied to the front and back surfaces of each at almost the same time using a roll coater at a coating amount of 150 g/m ² . on the other hand,
One surface board installed (0.8mm thickness x 1.2m width x 1.8m
The coated honeycomb core is superimposed on a length of coated steel plate, and then another surface plate is superimposed on it. In order to cure the adhesive, the laminated state was left under a compression pressure of 0.2 kg/cm ² for one day.
Create a honeycomb sandwich structure panel.

After cutting this panel into 5 cm width and 5 cm length, the tensile adhesive strength of each face plate was measured using an autograph, and it was found to be 3.7 Kg/cm ² and 3.5 Kg/cm ² , respectively. The difference was only slight. In addition, even though one end of the panel was held and force was applied in the direction of splitting, it did not peel off.

Comparative Example 1 The adhesive of Production Example 1 is applied to the entire back surface of each face plate as in the conventional method, and is pressed and bonded to a honeycomb core core material to create a honeycomb sandwich structure panel. When this panel was subjected to a surface plate tensile adhesive strength test, the strengths were 3.1 Kg/cm ² and 3.0 Kg/cm ² .

In this way, in Example 1, unlike Comparative Example 1, which applied the adhesive to the entire surface, the adhesive was effectively applied only to the effective adhesive area, and the adhesive strength was superior to that in Comparative Example 1. The amount of adhesive used can also be significantly reduced, resulting in significant labor savings in bonding work.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an example of a honeycomb sandwich structure panel obtained by the method of the present invention;
and FIG. 2 is a simplified side view showing an example of the operating steps of the method of the present invention, 1: honeycomb core core material, 2a, 2b: adhesive,
3a, 3b: surface plate, 4a, 5a and 4b, 5
b: Roll vs.

Claims (1)

[Claims] 1. When manufacturing a sandwich structure panel consisting of a honeycomb core as a core material and a surface plate adhered to it, a roll coater is used to coat the front and back surfaces of the honeycomb core with a viscosity of 8000 to 18000 cps and a thixotropy coefficient of 1.2.
An adhesive processing method for a honeycomb sandwich structure panel characterized by applying a moisture-curable liquid urethane adhesive of ~3.5 and then superimposing and bonding face plates on both sides of a honeycomb core.