JPS621822B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a decorative board having a resin-coated cured thin paper as a surface layer.

Conventionally, so-called printed decorative hardened paper, which is made by applying a small amount of urethane resin or aminoalkyd resin to printed thin paper and curing it, is well known as a pre-coated decorative hardened paper using thin paper. The production speed of this decorative hardened paper is extremely fast, at around several tens to 100 m/min, and the speed at which it can be laminated onto base materials such as plywood and particle board using a vinyl acetate emulsion type adhesive is also several tens of meters per minute.
It is quite fast at m/min. Therefore, this laminated decorative board is low in price and has excellent economic efficiency. However, because this decorative board has a very small amount of resin attached to the surface decorative paper, it does not have sufficient physical properties such as stain resistance, abrasion resistance, and weather resistance, and its appearance is similar to that of the surface layer of the base material. The so-called smearing phenomenon that appears on the surface of the laminate was conspicuous, and the laminate was poorly evaluated as a decorative laminate with poor surface smoothness and a lack of luxury.

On the other hand, decorative boards with a large amount of resin adhesion using decorative paper such as ordinary patterned paper include resin-coated hot-press type decorative boards such as melamine resin decorative boards and diallyl phthalate resin decorative boards, and polyester decorative boards. After-coat decorative laminates are known, and these decorative laminates have high resin content and have excellent physical properties such as abrasion resistance and stain resistance, as well as surface smoothness. It is difficult to reduce and is not necessarily economical.

The present applicant has previously proposed a method for producing decorative hardened paper using thin paper, which has a relatively large amount of resin deposited and can be mass-produced (Japanese Patent Application Laid-open No. 57098/1983). This decorative hardened paper can be continuously bonded to a base material such as plywood or particle board using a vinyl acetate emulsion type adhesive to form a decorative board. Furthermore, the obtained decorative board has a large amount of resin, unlike conventional so-called printed decorative boards, and therefore has excellent physical properties such as abrasion resistance, stain resistance, and weather resistance, and is also excellent in processability. However, the fading phenomenon caused by the base material during the production of decorative laminates cannot be alleviated unless a sealing treatment is performed using a composition containing abrasive powder and fillers such as calcium carbonate, which requires an increase in extra steps. There was a cost increase factor in not being able to do so.

The present inventors have investigated various methods of obtaining decorative laminates without any graining without performing the above-mentioned sealing treatment when producing decorative laminates using decorative hardened paper made of thin paper. The present inventors have discovered that a decorative board that fully achieves the above objectives can be obtained by laminating the two under pressure using a moisture-curing urethane adhesive as the adhesive for bonding the two together, and have thus arrived at the present invention. It is something.

That is, the present invention provides an unsaturated polyester resin composition containing a diallyl phthalate monomer with a basis weight of 15
When manufacturing decorative laminates by laminating hardened paper coated on ~55g/ ^m2 thin paper and cured, on a base material,
A moisture-curing urethane adhesive with an isocyanate group content of 7 to 20% by weight is used as the adhesive, and 30 to 100 g/ ^m2 of this is applied to the base material and laminated under pressure. It is a manufacturing method.

The cured paper used in the present invention is preferably one obtained by the method described in JP-A-55-57098, but is not limited to this method and can be obtained by applying the resin composition of the present invention. Any hardened paper will do. Thin paper having a basis weight of 15 to 55 g/m ² is suitable, and may be printed or untreated. Further, the thin paper may be treated with a resin in order to adjust the permeability of the resin or to increase the interpaper strength.
Thin paper with a basis weight of less than 15 g/m ² is undesirable because the strength of the paper itself is low, causing problems in workability when producing hardened paper, and poor hiding power as decorative paper. In addition, if the basis weight exceeds 55 g/ ^m2 , the permeability of the coating resin into the paper increases, and therefore the amount of resin deposited on the surface of the cured paper is relatively reduced, so that the surface characteristics as a decorative board are not sufficiently obtained. It is also undesirable that the flexibility of the cured paper itself is deteriorated.

In the present invention, as the resin component applied to the thin paper, an unsaturated polyester resin containing a diallyl phthalate monomer consisting of ortho, iso, and tele isomers is suitable from the viewpoint of physical properties as a decorative board.

Examples of unsaturated polyester resins include common unsaturated polyester resins, such as polybasic unsaturated acids such as maleic acid, fumaric acid, itaconic acid, phthalic acid, and adipic acid, or mixtures with saturated acids and ethylene glycol, propylene glycol. , reaction products with polyhydric alcohols such as diethylene glycol, or air-curable unsaturated polyester resins, such as tetrahydrophthalic acid, 3,6-endomethylenetetrahydrophthalic acid, methyl-3,6- Suitable are polyester resins produced from acids containing aliphatic cyclic unsaturated acids such as endomethylenetetrahydrophthalic acid, or alcohols containing allyl glycidyl ether in addition to the above as the alcohol component.

The proportion of diallyl phthalate monomer in the resin component is suitably 20 to 60% by weight. If the amount is less than 20% by weight, unfavorable surface properties may occur depending on the intended use of the decorative board. If it exceeds 60% by weight, the resin will shrink significantly during curing, making it difficult to produce cured paper.

As the base material for the decorative board, any commonly used base material may be used, but those containing an appropriate amount of moisture, such as lauan plywood and particle board, are particularly preferred. The present invention is characterized in that a moisture-curing urethane adhesive is used as the adhesive when laminating the cured paper on the base material. As mentioned above, when conventionally used vinyl acetate adhesives are applied without pre-treatment of the base material, the surface hardened paper uses tissue paper as a base paper, so the surface of the base material is exposed as is, making it possible to suppress the fading phenomenon. I couldn't do it. The effect of using the urethane adhesive according to the present invention is that the gas partially generated when the adhesive is cured by moisture is well balanced with the pressure during pressure bonding, and the unevenness on the surface of the base material is smoothed. It is presumed that this was to conceal it.

There are two types of moisture-curable urethane adhesives of the present invention: solvent-based and solvent-free, and either of them can be used. The urethane adhesive is a general term for adhesives made of compounds having terminal isocyanate groups such as polyisocyanate monomers, adducts of diisocyanate and alcohol, terminal isocyanate prepolymers, terminal isocyanate polyurethanes, etc. , tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), triphenylmethane triisocyanate (TTI), trimethylolpropane and TDI
and the above-mentioned MDI-based, TDI-based, and TTI-based prepolymers. The content of isocyanate groups in the adhesive is preferably in the range of 7 to 20% by weight, preferably 12 to 18% by weight from the viewpoint of adhesive performance and workability. If it is less than 7% by weight, the adhesive strength will not be sufficient, and if it exceeds 20% by weight, the pot life will be shortened and workability will be reduced. The adhesive of the present invention may contain fillers such as titanium oxide, calcium carbonate, clay, etc., if necessary.

One embodiment of the present invention will be described below.
To first apply the adhesive to the substrate, a commonly used roll coater or knife coater is suitable. The coating amount varies depending on the type of substrate, but is usually in the range of 30 to 100 g/m ² . The amount of application
If it is less than 30 g/m ² , it is not preferable because it may cause dullness. Moreover, if the amount exceeds 100 g/m ² , it will take too long to cure to obtain sufficient adhesive strength. When using a solvent-based adhesive as an adhesive, a suitable drying step is required. Next, the cured paper is laminated on the base material using a roll laminator or the like at room temperature, and about 10 to 100 sheets are stacked in a suitable press with a plate placed on the decorative side of the cured paper. As the caul plate, a smooth plate such as a stainless steel plate, an aluminum plate, or a polyvinyl chloride plate is used, and if both sides of the caul plate can be used, they can be stacked so that the decorative surfaces face each other. The surface of the backing plate must be free of foreign matter such as dust and scratches. The decorative boards stacked inside the press weigh 5 to 7 kg at room temperature.
A pressure of cm ² is applied. In this state, it is removed from the clamping set press machine using a turnbuckle and left in the clamped state. The pressing time may be appropriately determined depending on the moisture in the base material, the temperature, and the amount of adhesive applied. After a predetermined period of time has elapsed, the turnpeckle is released, and a well-bonded decorative board without any markings is obtained.

The decorative board thus obtained has excellent surface properties and a luxurious appearance.

The present invention will be explained below with reference to Examples.

Example: Air-curing unsaturated polyester resin produced from maleic acid, tetrahydrophthalic acid, and diethylene glycol by a conventional method (acid value 16, softening point 5°C)
65 parts by weight, diallyl orthophthalate monomer 35
A resin composition consisting of 1 part by weight of benzoyl peroxide, 1 part by weight of methyl ethyl ketone peroxide, 0.2 parts by weight of cobalt octylate (cobalt content 8% by weight), 4 parts by weight of a matting agent, and 0.3 parts by weight of a leveling agent was mixed with wood grain. Basis weight 30 with printed pattern
The composition was continuously coated onto a thin paper of 40 g/m ² using a roll coater, and then cured in a hot air oven at 100° ^C. while applying tension to the thin paper to obtain a decorative cured paper. Next, the rough thickness of the conduit part is 2.7
Solvent-free moisture-curing urethane adhesive (TDI prepolymer "A-
439'' (manufactured by Takeda Pharmaceutical Company) using a roll coater.
60 g/m ² was applied, and this was laminated at room temperature using the above-mentioned decorative hardened paper roll laminator, and 150 sheets of the above-mentioned decorative board were stacked in a press using a polyvinyl chloride board with a thickness of about 2 mm as a backing plate. 6Kg/ ^cm2 at room temperature
After applying the load, tighten the turnbuckles on all sides in this state, take it out of the press and press it for 15 minutes.
I left it for a while. After 15 hours, the turnbuckle was released and the resulting decorative board had no graininess.
It was a decorative board with an almost completely smooth surface.

Comparative Example The same decorative hardened paper and plywood as in the example were used, and vinyl acetate emulsion type adhesive (solid content 46
Roll coater on the above plywood using 80% by weight)
After drying for ³ seconds in a hot air dryer at 110°C, the decorative hardened paper was applied using a rolleminator heated to 90°C. The decorative board thus obtained had significant fading in some areas.

Claims (1)

[Claims] 1. When manufacturing a decorative board by laminating the cured paper, which is obtained by applying an unsaturated polyester resin composition containing a diallyl phthalate monomer to a thin paper with a basis weight of 15 to 55 g/m ² and curing it, to a base material, isocyanate is used as an adhesive. Using a moisture-curing urethane adhesive with a base content of 7 to 20% by weight, apply 30 to 100% of adhesive to the base material.
A method for producing a decorative board characterized by applying g/m ² and laminating it under pressure.