JPS6021695B2 - Adhesion method of soft urethane foam and sheet material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of adhering a sheet-like material to a soft urethane foam that is widely used as cushioning materials and cold weather clothing.

A product in which a soft urethane foam and a sheet-like material are bonded has the effect of stabilizing the dimensions and simplifying the sewing process with the sheet-like material.

Methods for obtaining this adhesive include the flame method, in which a gas flame is applied directly to the surface of the urethane foam, and the sheet material is immediately crimped immediately after the surface melts; the adhesive is a two-component solution type, a powder type; A method using an acrylic emulsion has been proposed. However, each of these methods has its own drawbacks. That is, in the flame method, since urethane foam, which is a special combustible material, is directly exposed to flame, it is necessary to strictly control the flame.
Furthermore, in the method of using a two-component adhesive solution, it is not only necessary to mix the base resin and hardening agent in an appropriate ratio, but also requires equipment to prevent environmental pollution caused by organic solvents generated when drying the adhesive. Become. In addition, in the method using acrylic emulsion, it is easy to use because it is based on water content, but there is a problem with water resistance, and it cannot be used in areas that require such characteristics. Furthermore, as is well known, sensitive urethane foam has continuous cells, and textiles and the like also have many pores.

If a liquid adhesive is simply applied to such a porous structure, the adhesive will penetrate into the pores and the effective coating amount required for bonding will not be obtained. Increasing the amount of application is effective from the viewpoint of adhesive strength, but not only is it less economical, but it also causes the adhesive that has penetrated into the pores to solidify, giving it a hard feel and reducing the feel of the adhesive. This results in the disadvantage that the particles may spill out onto the surface of the sheet-like material. To solve these problems, fillers such as silicasil are added to the adhesive to prevent penetration through thickening and sealing effects, or the adhesive is applied to silicone paper in advance and allowed to dry halfway to increase the occupancy. A method of transferring the image onto an adherend has been proposed. However, the former has the drawback that it has a weak thickening effect in non-aqueous systems and settles during long-term storage, and the emulsion system has the drawback that it is difficult to thicken to the extent that penetration can be prevented.
The latter method also has the disadvantage of increased equipment costs. An object of the present invention is to provide an inexpensive method for obtaining an adhesively integrated product of a flexible urethane foam and a sheet-like material without the above-mentioned drawbacks.

That is, in the method of the present invention, a prepolymer composition containing 20% or more of a hydrophilic urethane prepolymer having an isocyanate group at the end is applied to a urethane foam or sheet, and the composition is made into a foam by adding moisture. Alternatively, a paste is formed, a sheet or urethane foam is pressed through the paste, and then dried. Hydrophilic urethane prepolymers with isocyanate groups at the ends are highly reactive with moisture, and during the process of curing, the -NCO groups react with water to generate carbon dioxide gas and form a foam. , to form a paste by thickening.

At this stage, the adhesive loses its normal fluidity, but it has a chicken-tropic character that flows when force is applied. Therefore, at this stage, the adhesive does not penetrate into the pores of the urethane foam or sheet material, but when the adherends are pressed together, a slight flow occurs and the anchor has a large effect on the adhesive strength. It is effective and maintains sufficient adhesion because the adhesive is not completely cured. The mixing ratio of the hydrophilic urethane prepolymer and other prepolymers varies depending on the temperature and humidity during the bonding process, the method of application, the speed of bonding, etc., but if the content of the hydrophilic urethane prepolymer is 10% or less, it will not be added. Moisture is separated and foaming and pasting do not occur.
If it is 10 to 20%, the degree of foaming and pasting is small, resulting in insufficient adhesion.

If it is 20% or more, foaming and pasting will occur sufficiently and the method of the present invention will be suitable.

An example of a method for carrying out the present invention will be described with reference to the drawings.

A urethane foam 1 wound into a roll is continuously unwound, and an adhesive 2 is applied by a roll coater 3. Next, moisture is applied to the surface of the adhesive using a spray 4, and the adhesive is overlapped with a sheet-like material 5 and rolled up. After that, it is dried to form an adhesive. Here, a general method such as a roll coating method or a spray coating method can be adopted as a method for applying the adhesive. Moisture can be added to the applied composition by steam, spray, etc., but it is not necessary to add moisture in times of high temperature and humidity, such as during the rainy season, or when the bonded material is left for a long time. None. The rolled-up bond may be dried naturally in the rolled state, or may be heated and dried while being unrolled again. It is also possible to attach urethane foam to a sheet-like material and dry it without winding it up. A feature of the present invention is that moisture is applied after applying the adhesive.

This method does not require fire and can use organic solvents to adjust the viscosity, making it a highly safe and useful method with little environmental pollution. The prepolymer composition used in the present invention is a urethane prepolymer containing at least 20% of a hydrophilic prepolymer having terminal isocyanate groups. The hydrophilic prepolymer is a polyether type polyol having two or more hydroxyl groups per molecular weight (for example, polyhydroxy compounds such as polyethylene glycol, polypropylene glycol, copolymers of ethylene oxide and propylene oxide, and trimethylolpropane) in which ethylene oxide or propylene oxide is added. It is a prepolymer obtained by reacting a polyisocyanate compound (for example, TD1, MDI, etc.) with a polyisocyanate compound (for example, TD1, MDI, etc.) under the condition of NCO/OH>2. In addition, in the reaction between the polyether type polyol and the polyisocyanate compound, the exemplified compounds may be used alone or in combination. The prepolymer to be mixed with the hydrophilic prepolymer is a polyester polyol (for example, a reaction product of a polycarboxy compound such as adipic acid or phthalic acid and a polyhydric alcohol such as ethylene glycol or trimethylolpropane).
This is a non-hydrophilic urethane prepolymer, such as a urethane prepolymer with terminal isocyanate groups obtained by reacting a polyisocyanate compound with a polyisocyanate compound.

Further, the prepolymer composition that is the adhesive of the present invention may be mixed after producing each prepolymer, or may be used by mixing polyether polyol and polyester polyol during reaction.

The prepolymer composition of the present invention is usually used in a solvent-free state, but depending on the conditions of the polymer, a small amount of a solvent such as methyl ethyl ketone, toluene, or ethyl keyate may be added to adjust the viscosity.

It is also possible to add a surfactant to hold the carbon dioxide gas generated when water is added in the adhesive. In this case, the foaming of the adhesive increases the volume expansion, reducing the amount of application and making it even more economical. Moreover, the texture can be improved.

Examples are shown below.

Example 1 400 parts of polypropylene glycol with a molecular weight of 2000 and diphenylmethane diisocyanate 13 with a molecular weight of 70 to 8
The reaction was carried out at 0 qo to obtain a hydrophilic prepolymer A having a viscosity of 50 poise.

Next, 40 bases of polyester diol of 9 KOH/240% of hydroxyl value, which is a reaction product of adipic acid and ethylene glycol, and 24 bases of tolylene diisocyanate were added.
The reaction was carried out at 0 to 90 qo to obtain a non-hydrophilic prepolymer B having a viscosity of 150 poise.

A and B were mixed in a nitrogen stream to produce a prebolimer composition. This composition was applied using the equipment shown in the figure, and 105q
Table 1 shows the performance of the adhesive obtained by drying at o for 1 minute. Example 2 Polyol 40 with a molecular weight of 2500 obtained by copolymerizing ethylene oxide and propylene oxide
Anchorage and tolylene diisocyanate 9 anchorage were reacted in the same manner as in Example 1 to obtain a prepolymer C having a viscosity of 60 poise.

Table 2 shows the results of mixing prepolymers B and C and surfactant SH-193 (manufactured by Toray Silicone) and bonding urethane foam and fabric in the same manner as in Example 1.

Table 1 Pre-bolimer formulation and adhesion (Note) The adhesion rate of urethane foam to textiles is shown in parentheses (*).

(During test) Table 2 Effect of surfactant

[Brief explanation of drawings]

FIG. 2 is a process diagram illustrating implementation of the present invention.

Claims (1)

[Scope of Claims] 1. In a method for bonding a flexible urethane foam and a sheet-like article, a urethane prepolymer composition containing at least 20% of a hydrophilic urethane prepolymer having an isocyanate group at the end is applied to an unwound urethane foam or The urethane prepolymer is applied to a sheet, and then water is added to make the urethane prepolymer into a foam or paste, and a sheet or urethane foam is pressed through the foam to obtain an adhesive, which is then dried. A method for adhering a soft urethane foam and a sheet-like object, characterized in that the adhesive is made from a soft urethane foam. 2. The adhesion method according to claim 1, wherein the hydrophilic urethane prepolymer is a polyether type polyol and a polyisocyanate. 3. The adhesion method according to claim 1, wherein the polyether type polyol is an ethylene oxide and propylene oxide copolymer.