JPS5893766A - Adhesive composition consisting of self-emulsifiable polyisocyanate and formalin condensation resin - Google Patents

Abstract

PURPOSE:To provide an adhesive compsn. having water resistance and stability and suitable as a wood adhesive, by using a formalin condensation resin and a self-emulsifiable polyisocyanate in combination. CONSTITUTION:A polyisocyanate emulsion (A) obtd. by emulsion-dispersing a self-emulsifiable polyisocyanate such as ''Colonate 3053 '' (a product of Nippon Polyurethane Kogyo K.K.) in water, and a resin soln. of a formalin condensation resin (B) such as a urea/formalin resin, are mixed together in a weight ratio (on a solid basis) of 1/10-10/10 to obtain an adhesive compsn. Components A and B may be simultaneously applied to an adherend while controlling the mixing ratio by using a sprayer which can simultaneously spray components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive composition having water resistance and excellent stability, and is particularly useful as a wood adhesive.

Currently, water-soluble formalin-based condensation resins such as urea resin, melamine resin, and phenolic resin are used as adhesives for plywood or secondary processing of plywood, chipboard, laminated wood, etc. Adhesive is generated during its application processing. Alternatively, formaldehyde remaining in products using these adhesives may be unfavorable from an environmental health perspective.

Conventionally, there has been a technique in which organic polyisocyanate is used in combination with other organic hydrophilic solvents or surfactants for the purpose of suppressing formalin release from formalin-based adhesives and enhancing water resistance, as disclosed in JP-A No. 49-22438. and Japanese Patent Application Publication No. 1973-
When using these in the C2 aqueous solvent described in No. 691.34, it is extremely difficult to disperse the polyisocyanate alone, and it is difficult to obtain uniformity in large processed products even by forced stirring. there were.

The inventors of the present invention carried out intensive research with the greatest goal of improving the above drawbacks, and as a result, they discovered that the above drawbacks could be improved by using a self-emulsifying polyisocyanate and a formalin-based condensation resin in combination.

That is, the present invention relates to an adhesive composition comprising a self-emulsifying polyisocyanate and a formalin-based condensation resin.

The greatest feature of the present invention is that the surface of the active incyanate is coated with a polyurea compound by using a self-emulsifying polyisocyanate and dispersing and emulsifying the polyisocyanate component, which is highly reactive with the active hydrogen source, in water. It generates fine particles, temporarily suppresses their reaction activity, and facilitates their use in combination with formalin-based condensed resins.Furthermore, by using self-emulsifying polyisocyanates, they can be used during wood processing or with these adhesives. The aim is to reduce the absolute amount of formalin emitted from products using this product, thereby reducing environmental pollution.

In addition, by using a formalin-based condensation resin and a self-emulsifying polyisocyanate in combination, the deterioration of various wood products over time, such as water resistance, etc. can be observed. Any of these can be used, but preferably the effective NCO content is high.

It has low viscosity and good water dispersibility. Two examples are RO (C
H, CH, 0)nCONHX (in the formula, R has 1 to 4 carbon atoms
, n is an integer such that the compound contains on average at least 5 oxyethylene groups, and X is the residue of a di- or polyincyanate containing at least one free (including incyanate) containing a nonionic surfactant represented by the general formula:

In addition, in the present invention, one of the self-emulsifying polyisocyanates
Species or mixtures of two or more species can be used.

The formalin-based condensation resins used in the present invention include urea-formalin-based resins, melamine-formalin-based resins, phenol-formalin-based resins, etc. One or more of these resins may be used in combination or they may be co-condensed. Things, etc.

Conventionally, these formalin-based condensation resins are generally commercially available in powder or liquid form, and when used, they must be diluted with water or other solvents or used in liquid form, but in this case, the solid content is generally 10% by weight. It is often used in a range of 76 parts by weight.

When using these resins alone for adhesion.

After adding curing agents, additives, thickeners, etc. suitable for each resin, it was applied to an object to be adhered, and was pressed by pressing at room temperature or under heating, and was then subjected to I & final curing to obtain adhesive strength.

Formalin-based adhesives are usually used with a solid content of about 50% and often contain about 50% moisture, so it is necessary to dry the adherend in order to shorten the heat pressure time. be.

However, since self-emulsifying polyisocyanate can be emulsified with water at any ratio, the ratio of water included when applying the glue can be easily adjusted, which can shorten the drying process of the adhesive and reduce the water content. It has the advantage of having a wide tolerance range.

The resin concentration of the adhesive according to the present invention ranges from 10% by weight to 70% by weight.
It can be used within a range of % by weight.

The self-emulsifying polyisocyanate/formalin resin can be mixed in almost any ratio, but in the present invention, a weight ratio of 1 ro-shoulder is preferred.

When using this adhesive composition, the self-emulsifying polyinsyanate and formalin-based condensation resin may be mixed in advance and applied to the adherend, or the mixing ratio may be adjusted to Section A using a two-liquid jetting type dispensing machine. After applying it to the object to be adhered, leave it at room temperature or under heating.

A product can be easily obtained by crimping with a press or the like. In addition, when using this adhesive composition, gypsum and clay may be used as publicly known fillers.

Talc, blood powder, soybean powder, wheat flour, aluminum hydroxide, etc. can also be used.

These additives useful for curing control can be used in an amount of 1 to 30 parts by weight per 100 parts by weight of the constituent resin components, but preferably 1 to 20 parts by weight.

Conditions 9 for curing, for example, temperature for 9 hours.

To adjust the pressure, etc., add acids and salts during 4 minutes of composition.

Base 9 etc. can be added.

EXAMPLES Next, the present invention will be further explained in detail with reference to Examples, but the present invention is not limited to these Examples.

Note that parts and % in Examples and Comparative Examples indicate parts by weight and % by weight, respectively.

Example 1 75 parts of a self-emulsifying polyisocyanate, Alcoronate 3053 (trade name, manufactured by Nippon Polyurethane Industries, Ltd., hereinafter the same), was added to 50 parts of water and mixed by stirring at 100 Orpm using a stirrer to obtain a polyisocyanate emulsion A liquid. ,,
:.

Next, 24 parts of a 20% aqueous anthone chloride solution was added to 300 parts of urea resin (Oshika Shinko W&170B, solid content 66% or less) and mixed at 100° rpm with a stirrer to obtain urea resin liquid B.

120 parts of polyisocyanate W"f solution A were added to 262 parts of urea resin solution B and mixed well at 100 rpm using a stirrer to obtain a blended paste solution α).

Use this as an adhesive and spray it on wood chips (lauan) under the following conditions while mixing using a blender.
One piece of particle board was made.

Spraying conditions Incyanate content: 3.5% Urea resin content: 7.
8% pressure 40 Kg/c4, temperature 120℃ 9 hours 15
Seconds - (pressure time per 1tIuR of board) Physical properties Normal bending strength 1) 215 K? Bending strength after Arl boiling 1) 82jl/ctI (strength retention rate 40%) Comparative example 1゜Flat content 1125 using only urea resin in the same manner as in Example 1
The physical property values of the board obtained by processing with % were as follows.

Normal bending strength 1) 205 KgAfI bending after boiling (bending after boiling) OK 9 shoulder Example 2゜ 30 parts of water was gradually added to 20 parts of wheat flour and mixed well, and the mixture obtained in Example 1. 100 parts of the blended paste solution (1) obtained in step (1) was added and mixed by stirring at 100 rpm using a stirrer to obtain a blended paste tablet (2). Using this as an adhesive, plywood was prepared under the following conditions.

9 red veneer veneer composition! , 0 +1. r-1-1
,0m coating amount 36 g / 30
X 30 Ro Cold Press Pressure 10? /m, time: 100 seconds hot press, pressure: 1oh/ilt, temperature: 105°C.

Time 240 seconds Adhesive strength Normal adhesive strength 18.4 Immediate/d Wood breakage rate 100% Boiling repeated bonding 11.0Kg/cI Wood breakage rate 61%
Adherence 2) Comparative Example 2 40 parts of water was gradually added to 40 parts of wheat flour and mixed well. To this, 100 parts of urea resin and 703 parts of ammonium chloride were added, and the mixture was stirred and mixed with a stirrer at 1 OOO rpm. A plywood was prepared in the same manner as in Example 2.

Adhesive Strength Ordinary Adhesive Strength 2) 15.5 Immediate/- Wood Breakage Rate 50% Boiled Repeated Adhesion Strength 2) 011/aI Wood Breakage Rate 0% Example 3 Add 50 parts of Coronet) 3053 to 50 parts of water.

The mixture was stirred and mixed using a stirrer at 200 rpm to obtain a polyisocyanate emulsion C solution.

Separately, 20% to 100 parts of melamine urea cocondensation resin (Aikayuri UM-82 manufactured by Aikanigyo, solid content 51% or less, same)
Add 10 parts of ammonium chloride aqueous solution and mix with a stirrer to 1000
The mixture was stirred and mixed at rpm to obtain a melamine urea cocondensation resin liquid.

100 parts of polyisocyanate emulsion solution C was added to 110 parts of the above solution, and the mixture was thoroughly mixed with a stirrer at 100° rpm to obtain a blended paste solution.

Using this as an adhesive, plywood was prepared under the following conditions.

Veneer veneer 2.0 mm 3-braid coating amount 40 g/30 x 30 cold press
Pressure 1oKf/*r time 100 seconds hot press Pressure 1oKy/cd, temperature 110°C.

Time 10 minutes Adhesive strength Normal adhesive strength 2) 18.5kC9/cM Wood breakage rate 100
% continuous boiling adhesive strength 2) 10.5 KP/cJ Wood breakage rate 70% Comparative Example 3 10 parts Y of a 20% ammonium chloride aqueous solution was added to 100 parts melamine urea co-condensed resin and mixed well to obtain a blended paste solution.

This mixed paste solution was used in Example 3. Plywood was prepared by processing in the same manner as above.

Adhesive strength Normal adhesive strength 2) 16.3Ilf/CrA Wood breakage rate 9
0% continuous boiling adhesive strength 2) 6.51f/Ci
Wood breakage rate: 20% Example 4 100 parts of water and 305 parts of Coronate were stirred and mixed with a stirrer and a trowel at 1000 rpm to obtain polyisocyanate emulsion F. Separately, 10 parts of soy flour was added.
30 parts of water was slowly added to the mixture and mixed well, and a water-soluble Funol resin (Aikaneo Resin P-7 manufactured by Aikani Co., Ltd.) was added to this mixture.
3. Add 100 parts (solid content 53%) and 0.1 part of caustic soda to a stirrer. The mixture was thoroughly mixed using Orpm to obtain water-soluble phenol-I solution F.

Add 90 parts of water-soluble Tuonol F solution to 35 parts of Polyisocyanate Emulgilon E solution, and stir at 1000 r' with a stirrer.
pm and mixed well to obtain a blended paste solution. Using this as an adhesive, plywood was prepared under the following conditions.

Veneer veneer 1.0m 3 ply coating Amount 30g/30x30σ Cold press Pressure 10Kp/cJ, time 100 seconds Hot press Pressure 10KIi/cJ, temperature 135°C 2 hours 180 seconds Adhesion strength Normal adhesive strength 2) 18.8 Immediately/ct! Wood breakage rate 1
00% hot/cold water adhesive strength 2) 16.0 Kg1ca Wood breakage rate 55% Comparative Example 4 Plywood was prepared in the same manner as in Example 4 using water-soluble Tuonol F liquid.

Adhesive strength

Claims (1)

[Claims] Adhesive composition consisting of self-emulsifying polyisocyanate and formalin-based condensation resin