JPH07286158A - Bonding of porous material - Google Patents

Abstract

PURPOSE:To provide a process for bonding a porous material such as polyurethane foam, producible with a simple production facility compared with conventional process and achieving high bonding strength by the application of a small amount of adhesive. CONSTITUTION:A porous adherend is bonded to a porous or nonporous adherend by coating the surface of the adherend with a prepolymer having isocyanate group on the terminal and containing 1-10wt.% of free isocyanate group, contacting the prepolymer with steam, contacting both adherends with each other and bonding with pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adhering a porous material.

[0002]

2. Description of the Related Art Conventionally, as a method for adhering a porous material such as a plastic foam, a method using a water-soluble urethane prepolymer (Japanese Patent Publication No. 34994/1990, etc.) or a method using urethane foam (JP-A-58). No. 146386, etc.), a method using a heat-fusible skin (JP-A-55-1).
No. 23455, etc.) are known.

[0003]

However, in the method using the water-soluble urethane prepolymer, since the viscosity of the prepolymer is high, it is necessary to dilute it with a solvent, and the curing reaction is a two-component curing type. Therefore, there is a problem in that it must be mixed and cured in a strict mixing ratio. Further, the method using urethane foam has a problem that the adhesion strength to the porous adherend is low because the expansion ratio is low.
Further, the method of using the heat-meltable skin has a problem that the bonded portion becomes hard and a processed product having a soft touch cannot be obtained.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present inventors have proposed an adhesive method for applying a porous material with a small coating amount and a low elastic modulus and a high strength adhesive force. As a result of intensive studies, the present invention has been reached. That is, in the present invention, when adhering adherends at least one of which is porous, the content of free isocyanate groups (hereinafter abbreviated as NCO%) on the adherend surface is 1 to 10% by weight.
A prepolymer (A) having an isocyanate group (hereinafter, abbreviated as NCO group) at its end, which is then contacted with steam, and then superposed and pressure-bonded to each other. It is a bonding method.

In the present invention, the adherend which is porous includes wood, slate, paper, cloth, felt, plastic foam and the like having pores. Of these, preferred is plastic foam.

The NCO% of the prepolymer (A) used in the present invention is usually 1 to 10% by weight, preferably 1 to 8% by weight, more preferably 1 to 5% by weight. NCO% is 1
If the amount is less than 10% by weight or more than 10% by weight, the adhesive layer becomes hard and the processed product is uncomfortable when sitting on a car seat.

The solid content of the prepolymer (A) is usually 80.
˜100% by weight, preferably 90-100% by weight. Outside this range, (A) easily penetrates inside the porous material when applied, and high adhesive strength cannot be obtained.

The viscosity of the prepolymer (A) is usually 2000.
~ 10,000 cps / 30 ° C, preferably 3000-7
000 cps / 30 ° C. The viscosity of (A) is 2000
If it is lower than cps / 30 ° C., it penetrates into the inside of the porous material and a high adhesive strength cannot be obtained.

Prepolymer (A) used in the present invention
Can be obtained by reacting a stoichiometrically excess polyisocyanate with a polyol obtained by adding an alkylene oxide to an active hydrogen-containing compound by a conventional method.

Examples of the polyisocyanate constituting (A) include aliphatic polyisocyanates having 2 to 18 carbon atoms (excluding carbons in the NCO group) [eg stearyl isocyanate, hexamethylene diisocyanate (HDI), lysine diisocyanate]; carbon. Alicyclic isocyanate having a number of 4 to 15 [eg, cyclohexylene diisocyanate, isophorone isocyanate (IPDI), dicyclohexylmethane diisocyanate]; carbon number 8 to 15
Aroaliphatic polyisocyanate [for example, xylylene diisocyanate]; aromatic polyisocyanate having 6 to 20 carbon atoms [for example, phenylene diisocyanate, 2,4
-And / or 2,6-tolylene diisocyanate (TD
I), crude TDI, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), crude MD
I [crude diaminophenylmethane [a condensation product of formaldehyde and an aromatic amine (aniline) or a mixture thereof, diaminophenylmethane and a small amount (for example, 5 to 20).
% By weight) mixture with trifunctional or higher polyamine], polyarylene polyisocyanate (PAP)
I) and the like; modified products of these polyisocyanates (urethane group, carbodiimide group, allophanate group, urea group, buret group, uretdione group, uretonimine group, isocyanurate group, oxazolidone group-containing modified product, etc.); Polyisocyanates other than those described in JP-A-199160; and mixtures of two or more thereof. Among these, aromatic polyisocyanates and urethane group-modified products thereof are preferable, and among the aromatic polyisocyanates, TDI and crude TDI are particularly preferable.

Examples of the polyol constituting (A) include compounds having a structure in which alkylene oxide is added to an active hydrogen-containing compound such as polyhydric alcohol and polyhydric phenol.

Examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol and neopentyl glycol; glycerin, trimethylolpropane, pentaerythritol, Examples include polyhydric alcohols having 3 or more valences such as sorbitol and sucrose.

As polyhydric phenols, pyrogallol,
Polyphenols such as hydroquinone, bisphenols such as bisphenol A, condensates of phenol and formaldehyde (Novolak), US Pat. No. 3,265,641.
The polyphenols and the like described in the specification can be mentioned.

Two or more of these active hydrogen-containing compounds can be used in combination.

The preferred active hydrogen-containing compound is a polyhydric alcohol having two active hydrogen atoms in the molecule.

As the alkylene oxide (hereinafter abbreviated as AO) added to the above active hydrogen-containing compound, ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), tetrahydrofuran (hereinafter referred to as THF) (Abbreviation), butylene oxide, styrene oxide and the like. Of these, EO and PO
Are preferably used in combination, and PO alone is particularly preferably used.

The addition method of AO may be either block addition or random addition in which EO and other AO are mixed in advance and added, and there is no particular limitation.

The molecular weight of the polyol is usually 500 to 50.
00, preferably 1000 to 4000. Outside this range, the adhesive layer becomes hard and the processed product has a poor feel.

In the present invention, a catalyst may be used if necessary. As examples of the catalyst, amine catalysts and organometallic catalysts described on pages 118 to 122 of "Polyurethane Handbook" (published by Nikkan Kogyo Shimbun) can be used. Of these, preferred examples of the former are triethylenediamine and morpholine, and preferred examples of the latter are dibutyltin dilaurate, tin octylate and stannas octoate. You may use these in mixture of 2 or more types.

The method of applying the adhesive to the adherend in the bonding method of the present invention is not particularly limited, but a method of applying the adhesive to the adherend with a spatula or a brush, or a method of spraying can be used. Among these methods, the spray method is preferable from the viewpoint of workability.

The pressure conditions in the bonding method of the present invention are not particularly limited, but usually the temperature is 20 to 100 ° C., the pressure is 0.1 to 50 Kg / cm ² , and the time is 5 to 30 minutes.

[0022]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. In the following, "part" means part by weight and "%" means% by weight.

The abbreviations and compositions of the raw materials used in the examples and comparative examples are as follows. PPG-1: A polymer having a molecular weight of 1000 obtained by addition-polymerizing PO with propylene glycol. PPG-2: Propylene glycol with PO, then E
O is addition polymerized and has a molecular weight of 2000. EO in AO
The amount is 10% by weight. PPG-3: A polymer having a molecular weight of 400 obtained by addition-polymerizing PO with propylene glycol. Polyisocyanate-1: A reaction product of PPG-1 and a stoichiometric excess of TDI having an NCO% of 7.5%. Polyisocyanate-2: A reaction product of PPG-1 and a stoichiometric excess of MDI having an NCO% of 5.8%. Polyisocyanate-3: a reaction product of PPG-2 and a stoichiometric excess of TDI and having an NCO% of 4.0%. Polyisocyanate-4: A reaction product of PPG-1 and a stoichiometric excess of MDI and having an NCO% of 3.5%. Polyisocyanate-5: a reaction product of PPG-3 and a stoichiometric excess of TDI, having an NCO% of 14.6%.

Example 1 Soft Urethane Foam (Dimension 100 mm × 100 mm ×
10 mm) and polyisocyanate heated to 70 ° C.
No. 1 was sprayed so as to have the coating amount shown in Table 1, and then steam was sprayed, and it was sandwiched with the same kind of flexible urethane foam as described above, and 0.
It was pressure-bonded at 60 ° C. for 5 minutes with a pressure of ² kg / cm ² . The results of performance evaluation are shown in Table 1.

Example 2 The same operation as in Example 1 was carried out except that polyisocyanate-2 was used instead of polyisocyanate-1 in Example 1. The performance evaluation results are shown in Table 1.

Example 3 The same operation as in Example 1 was carried out except that polyisocyanate-3 was used instead of polyisocyanate-1 in Example 1. The performance evaluation results are shown in Table 1.

Example 4 The same operation as in Example 1 was carried out except that polyisocyanate-4 was used instead of polyisocyanate-1 in Example 1. The performance evaluation results are shown in Table 1.

Comparative Example 1 The same operation as in Example 1 was carried out except that a mixture of 80 parts of polyisocyanate-1 and 20 parts of methyl ethyl ketone was used in place of polyisocyanate-1. The performance evaluation results are shown in Table 1.

Comparative Example 2 Instead of polyisocyanate-1 in Example 1, 70 parts of polyisocyanate-2 and 3 parts of trichloroethane were used.
The same operation as in Example 1 was carried out except that a mixture with 0 part was used. The performance evaluation results are shown in Table 1.

Comparative Example 3 The same operation as in Example 1 was carried out except that polyisocyanate-5 was used in place of polyisocyanate-1 in Example 1. The performance evaluation results are shown in Table 1.

[0031]

[Table 1] ------------------ Coating amount Peel strength (Note 1) (g / m ² ) (kg / 25 mm) --- ------------- Example 1 50 1.5 or more (material destruction) Example 2 50 1.5 or more (material destruction) Example 3 501 .5 or more (material destruction) Example 4 50 1.5 or more (material destruction) ---------------------- Comparative Example 1 50 No adhesion Comparative Example 2 50 No Adhesion Comparative Example 3 50 No Adhesion ----------------------- (Note 1) Autograph (Shimadzu) used, Cross head speed 100 mm / min, T-shaped peeling.

[0032]

As compared with the conventional method, the method for adhering a porous material according to the present invention has a simpler manufacturing apparatus, has a stronger adhesive strength, and exhibits a sufficient adhesive strength in a short time with a small coating amount. ,
Furthermore, since the adhesive surface has the effect of having flexibility, it is most suitable when applied to the manufacture of automobile seats.

Claims (1)

[Claims] 1. A prepolymer (A) having an isocyanate group at the end thereof having a free isocyanate group content of 1 to 10% by weight on the surface of the adherend when adhering adherends at least one of which is porous. A method for adhering a porous material, which comprises applying the above, contacting it with water vapor, and superposing the two on each other and adhering them under pressure.