JP2627436B2 - Foam resin adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention has a density of 0.6 g / cm ³ or less and a viscosity of 100 to 500 poise / 25.
At 500 ° C, bubbles with a diameter of 500 μm or less immediately after foaming
The adhesive of the present invention relates to a formaldehyde-based foamed resin adhesive occupying 0% or more, and is particularly suitable for bonding hardly adherent wood.

Hard-to-adhesive wood as referred to in the present invention includes coniferous wood such as hemlock, Douglas fir, larch, etc., which are liable to break, break out, or damage the surface, wood containing a high water content of 15% or more, and a lot of dirt. High-viscosity adhesives including foam of the present invention are bonded to veneers with lumber temperature of 45 ° C or higher, such as cruin wood and APITON wood, sawn wood, hard-wood with cracking, kapole wood and cracks. It has an excellent effect in the work process of wood that is difficult to do.

Therefore, the present invention provides a foamed resin adhesive capable of achieving high productivity and economic efficiency demanded by the recent wood industry, such as utilization of low-quality raw wood, energy saving, and cost reduction.

[Conventional technology]

Veneer cosmetic stick plywood, paper laminated plywood, laminated wood, manufacture of plywood, a roll method, such as a conventional spreader roll and reverse coater, a density 1 g / cm ³ or more, the adhesive viscosity of 100 poise or less at 25 ° C. A general method is to apply and adhere to an adherend.

[Problems to be solved by the invention]

However, according to this conventional method, the adhesive is relatively low in viscosity, so that the paste easily exudes to the surface of the veneer. The pressure is applied to the adherend passing through the spreader roll from above and below, so that the surface of the fragile material is damaged. Easy to occur, Transient infiltration into porous adherends due to small adhesive particle diameter, easy to cause glue, Uniform coating with adhesive on adherends with uneven surface Therefore, it is difficult to apply a very small amount of adhesive to the material.For materials that have oozes on the surface, the adhesive is poorly wetted and the adhesiveness is reduced. When attached, the viscosity drops rapidly, easily causing hyperpenetration and lack of glue.For adherends with a high water content, the solid content concentration of the adhesive decreases due to the effect of moisture and the adhesive strength decreases. It has many problems and has a satisfactory adhesion to the adhesion of hard-to-bond wood. Could not Rukoto.

In addition, a foamed resin adhesive mainly composed of a formaldehyde-based resin solution and added with a general-purpose surfactant or a foam reinforcing agent such as a protein and foamed is usually used within 30 minutes to 2 hours after foaming. Although the method of applying and bonding to is also already known, the foamed resin adhesive obtained by these known methods,
Both generally have a viscosity of 100 poise / 25 ° C or less and a density of 0.6 g
/ cm ³ or more, the diameter of the bubble immediately after foaming is 500 μm or less, and the bubble is 50% or less, so that the bubble is uneven and fragile. Prevents seepage, prevents permeation of porous materials and hot veneers by over-penetration, enables application of a small amount even to rough surface materials, improves adhesive wetting of varnish materials, improves moisture content veneers No effect such as prevention of a decrease in adhesive strength has been obtained.

[Means for solving the problem]

The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, mainly use a known formaldehyde-based resin solution, and add a special anionic surfactant and a foam reinforcing agent such as protein to the resin solution. As a result, it is possible to obtain a foamed resin adhesive having high viscosity and uniform fine bubbles, and by using this foamed resin adhesive, it is possible to improve not only the adhesive performance of hardly adherent wood but also The present inventors have found that the bonding process can be stabilized and productivity and economy can be improved, and the present invention has been completed.

That is, the foamed resin adhesive of the present invention comprises 0.1 to 3 parts by weight of an anionic surfactant having at least one sulfone group and one or more carboxyl groups in the molecule per 100 parts by weight of a formaldehyde-based resin solution at room temperature. Using 0.2 to 10 parts by weight of a protein that swells or dissolves in water, the viscosity measured at 25 ° C by a BM type viscometer No. 4 rotor 12 rpm is 100
It is characterized in that the paste liquid has a size of up to 500 poise, a density of 0.6 g / cm ³ or less, and a bubble liquid having a diameter of 500 μm or less immediately after foaming (within 5 minutes after foaming) of 50% or more. At this time, the diameter of the foam and its content were measured by a method in which a foam paste solution was collected on a glass slide containing a scale, the diameter of the foam was measured with a microscope, and the number was counted to obtain an area ratio. .

Formaldehyde resin liquid used in the present invention, melamine, urea, guanamine, dicyandiamide, benzoguanamine, one or more compounds such as phenol, methanol, lower alcohols such as ethanol, formaldehyde, or glyoxal, acetaldehyde, Formaldehyde-based resin solution obtained by reacting aldehydes substituted with about 20% of formaldehyde with furfural and benzaldehyde together. The appropriate amount of use is 25 to 95 parts by weight based on 100 parts by weight of total resin solution. .

The formaldehyde-based resin liquid is used by adding an extender or / and a filler as needed. The extender or / and the filler used in this case are usually used for this kind of application. Specific examples thereof include rice flour, barley flour, wheat flour, wood flour, pulp powder, starch powder, resin powder, coconut shell powder, peach core husk powder, walnut husk powder, talc, clay, and zeolite. Examples thereof include organic and inorganic fillers such as titanium, and the amount thereof varies depending on the type, but is usually 1 to 50 parts by weight, preferably about 10 to 25 parts by weight, per 100 parts by weight of the formaldehyde-based resin liquid. Is appropriate.

The anionic surfactant having a sulfone group and a carboxyl group in the molecule is an acid such as diisobutylsulfosuccinic acid, diisooctylsulfosuccinic acid, ditridecylsulfosuccinic acid or a salt thereof, and the alkyl group has 4 carbon atoms.
To 24 linear or branched compounds. Examples of the salt include a sodium salt, an ammonium salt, a potassium salt, a calcium salt and the like, and a sodium salt is particularly preferable.

In addition, to these anionic surfactants, as long as the effect is not impaired, general-purpose surfactants such as higher alcohol sulfates, salts such as sodium alkylbenzene sulfonate and amine, alkyl naphthalene sulfonate, alkyl Diphenyl ether disulfonate,
A mixture of potassium oleate and the like can also be used.

The amount of the anionic surfactant to be added is 0.1 to 3 parts by weight, preferably 0.5 to 1.5 parts by weight, based on 100 parts by weight of the formaldehyde resin liquid.

If the added amount of the anionic surfactant is too large, the adhesiveness of the high moisture content wood becomes extremely poor, and if the amount is small, the foaming effect is insufficient and the improvement effect is not remarkable.

Proteins that swell or dissolve in water at room temperature are protein-containing substances such as low-temperature defatted soy flour, milk casein, blood meal, wheat gluten, and the amount added is formaldehyde resin solution 10.
It is used in an amount of 0.2 to 10 parts by weight, preferably 3 to 5 parts by weight based on 0 parts by weight.

Here, "normal temperature" means "average temperature throughout the year", and "swells or dissolves in water at normal temperature" means water of normal water temperature without heating, for example, water at room temperature. , Has the same meaning as swelling or dissolving.

If the amount of protein added is 10 parts by weight or more, the foam viscosity is high and the viscosity change is large, making it difficult to use as an adhesive.If the amount is 0.2 parts by weight or less, the effect of reinforcing the cell membrane of the foam is insufficient and the foam is insufficient. Is easy to break and has no improvement effect.

For the foamed resin adhesive of the present invention, an aqueous emulsion, a water-soluble polymer, a curing agent, and the like can be used as necessary.

Aqueous emulsions are those obtained by copolymerizing styrene, methyl methacrylate, and various vinyl monomers such as acrylonitrile with conjugated dienes such as butadiene and isoprene, aqueous emulsions such as polyvinyl acetate and polyvinyl chloride, chloroprene, butyl rubber, and polyvinylidene chloride. A latex such as polybutadiene, the amount of which is 75 parts by weight or less based on 100 parts by weight of a formaldehyde-based resin liquid.
The appropriate amount is 10 to 50 parts by weight, 10 to 50 parts by weight as a film-forming property and a softening agent, and 50 to 75 parts by weight as shrinkage and crack prevention.

If the content is 75 parts by weight or more, the price becomes high, which is economically disadvantageous.

The water-soluble polymer is methylcellulose, methylhydroxyethylcellulose, cellulose ethers such as methylhydroxypropylcellulose, polyvinyl alcohol, and the like. The compounding amount is 5 parts by weight or less, preferably 1 to 1 part by weight, based on 100 parts by weight of the formaldehyde resin liquid. 2 parts by weight.

The water-soluble polymer exhibits synergistic curing with the anionic surfactant, and improves the foaming property and foam stability of the adhesive. When the content of the water-soluble polymer is 5 parts by weight or more, not only does the flowability of the foam deteriorate, but also the water-resistant adhesive strength decreases.

The curing agent is necessary when using an amino resin liquid as a formaldehyde resin liquid, and acids such as citric acid, malic acid, oxalic acid, tartaric acid, phosphoric acid, hydrochloric acid, sulfuric acid, organic sulfonic acid, and the like. Salts such as sodium salt, potassium salt and ammonium salt can be used, and it is preferable to use an aqueous solution of these in an amount of 2 parts by weight or less based on 100 parts by weight of the resin liquid.

The adhesive of the present invention can be foamed using the usual foaming equipment used to foam this type of adhesive. At the time of foaming, a foamed resin adhesive having desired air bubbles and density can be obtained by adjusting the amount of compressed air, the stirring speed, and the like according to a usual method without particular consideration.

〔The invention's effect〕

The foamed resin adhesive of the present invention has a moderately adjustable viscosity and stable air bubbles, and can easily adjust the amount of coating. Can be applied.

In addition, due to the presence of the surfactant having a sulfone group and a carboxyl group, the adhesion of a poorly wet adherend such as a varnish material is improved. The presence of water-swellable or soluble proteins and, if desired, aqueous emulsions and water-soluble polymers enhance the cell membrane of the foamed foam, making it even and stable without causing high penetration of the adherend with high material temperature A good adhesive coating can be maintained.

Since the diameter of the foam immediately after the foaming of the adhesive is fine and uniform, that is, 500 μm or less, and forming a hard cell film, transient seepage and diffusion are unlikely to occur, and a stable adhesive force to high-moisture-content wood is exhibited.

〔Example〕

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

Example 1 A commercially available modified phenol resin liquid (manufactured by Hosei Oil Co., Ltd., PL
-160, non-volatile content 55%) 100g, defatted soy flour 5g, flour 2
0g, carboxy-modified SBR (manufactured by Nippon Synthetic Rubber Co., Ltd., SBR-
0597) 10 g, water 10 g, ammonium chloride 0.5 g as a curing agent
Was mixed with a resin solution, and various surfactants were added to prepare an adhesive solution.

The adhesive liquid was mixed with compressed air in the middle of the line, and foamed and foamed with an Oaks mixer (manufactured by Suga Machine Co., Ltd.) under the conditions of a back pressure of 2 kg / cm ² , a rotor rotation speed of 400 rpm, and a discharge hose of 2 m. An adhesive was obtained.

The resulting foamed resin adhesive was discharged from a nozzle in a curtain shape onto the surface of a high moisture content veneer, applied in a fixed amount, and then subjected to an adhesion test. Table 1 shows the results.

Example 2 Table 2 shows the results of bonding a quinine single veneer of hardly adherent wood with the foamed resin adhesive obtained by the method of Test Nos. 1, 2, 6, and 9 of Example 1.

As a comparative example, 100 g of a commercially available modified phenol resin solution (PL-160, non-volatile content: 55%, manufactured by Hosei Oil Co., Ltd.)
A similar test was conducted using a foamed resin adhesive prepared by mixing 20 g of flour, 10 g of water, and 0.5 g of ammonium chloride.

Example 3 In the formulation of Test No. 6 of Example 1, a foamed resin adhesive prepared by changing the content of the protein, the aqueous emulsion, and the water-soluble polymer was used, and there were many surface irregularities as an adherend. Therefore, the same test was performed using larch veneer, which is difficult to apply in a small amount. Table 3 shows the results.

Example 4 0.3 m thick using the foamed resin adhesive prepared by the formulation of Test No. 6 of Example 1 and the formulation of Comparative Example of Example 2.
The bonding of the veneer veneer was carried out. Table 4 shows the results.

Example 5 Commercially available urea resin liquid (manufactured by Hosei Oil Co., Ltd., UL-002, nonvolatile content 50%), melamine resin solution (manufactured by Hosei Oil Co., Ltd., ML-044, nonvolatile content 5) were used as formaldehyde resin liquids.
5%) and phenol resin liquid (manufactured by Hosei Oil Co., Ltd., PF
-109, 45% non-volatile content) were separately used, and in each of these resin solutions, blood powder as a protein, and dialkyl sulfosuccinate soda salt as an anionic surfactant (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. ) [Invention] and sodium alkylbenzenesulfonate (Neogen, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) [control] were added separately, and the other adhesive liquids were prepared according to the formulations shown in Tables 5 to 7 for the others. did.

The adhesive liquid was foamed and foamed in the same manner as in Example 1 to obtain a foamed resin adhesive.

The obtained foamed resin adhesive was bonded to a veneer under the bonding conditions for each resin liquid described in Tables 5 to 7, and an adhesion test was performed. The results are summarized for each resin liquid, and
It is shown in the table.

As clearly seen from the above results, the foamed resin adhesive of the present invention is extremely effective especially for bonding hardly adherent wood.

Claims (2)

(57) [Claims] 1. A foamed resin adhesive mainly composed of a formaldehyde resin liquid, wherein 100 parts by weight of the resin liquid is
Using 0.1 to 3 parts by weight of an anionic surfactant having a sulfone group and a carboxyl group in the molecule and 0.2 to 10 parts by weight of a protein which swells or dissolves in water at normal temperature, the viscosity is 25%.
100-500 poise at ° C., density of 0.6 g / cm ³ or less, foaming resin adhesive, wherein the diameter of the foam immediately after foaming was sizing liquid containing less bubbles 500 [mu] m 50% or more. 2. The method according to claim 1, wherein 75 parts by weight or less of an aqueous emulsion and / or 5 parts by weight or less of a water-soluble polymer are used in addition to said anionic surfactant and protein. Foam resin adhesive.