JPH082626B2 - Method for manufacturing surface-reinforced decorative plywood - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a novel method for producing a plywood having a surface veneer reinforced with a synthetic resin, that is, a surface-reinforced decorative plywood.

<Prior Art> A wood product surface-reinforced with a synthetic resin is made of a material obtained by impregnating wood with a synthetic resin and then polymerizing and curing the synthetic resin. Since it has excellent properties such as high mechanical strength, low water absorption and hygroscopicity, and high chemical resistance, it has attracted attention in the field of construction materials and the like.

This method for producing synthetic resin reinforced wood is characterized in that a treatment liquid consisting of a monomer or intermediate of a synthetic resin as a raw material and a polymerization initiator is injected into the wood by operations such as depressurization and pressurization.
It comprises a step and a second step of polymerizing and curing the synthetic resin by heat or light.

<Problems to be Solved by the Invention> When such a conventional method is used, special equipment is required for injecting the treatment liquid into the wood in order to carry out the first step, and sufficient recovery of the used chemicals is required. This is not practical as an industrial mass production method because the entire manufacturing process becomes complicated and long, because it cannot be performed and it takes a long time from the injection of the treatment liquid to the curing of the synthetic resin.

<Means for Solving the Problems> In view of the present situation as described above, the present invention omits the synthetic resin injection step, which has been performed separately from the conventional plywood manufacturing step, and is performed during the normal decorative plywood manufacturing step. It was completed for the purpose of injecting a synthetic resin and polymerizing and curing.

That is, the present invention, by applying a mixture of an adhesive and a radical polymerization initiator to the surface of the base plate, laminating a wood veneer on this, by applying a radical polymerizable resin on the surface of the wood veneer A method for producing a surface-reinforced decorative plywood characterized by comprising impregnating a mixture, the radical-polymerizable resin, and the wood veneer, and then activating the radical-polymerization initiator in the mixture to cure the radical-polymerizable resin. is there.

The radical polymerization initiator used in the method of the present invention can be generally classified into an initiator that initiates polymerization by heat (thermal polymerization initiator) and an initiator that initiates polymerization by light (photosensitizer). it can. Examples of the thermal polymerization initiator include peroxides such as benzoyl peroxide, cumene hydroperoxy and t-butyl peroxide, azo compounds such as azobisisobutyronitrile and diazominoazobenzene, and diazo compounds. Examples of the sensitizer include carbonyl compounds such as diacetyl, benzophenone, benzyl, benzaldehyde and cyclohexanone, and azo compounds such as azobisisobutyronitrile and azomethane. Use of one or more of these radical polymerization initiators You can

As the adhesive, an adhesive generally used in the plywood manufacturing process can be used, and specifically, it is represented by a phenol resin type, a resorcinol resin type, a urea resin type, a melamine resin type, an epoxy resin type, a latex type and the like. Thermosetting or room temperature curable adhesives are preferred.

The addition amount of the radical polymerization initiator in the mixture is preferably 0.1 to 10% by weight with respect to the adhesive.

A polymerization accelerator may be added to the mixture of the radical polymerization initiator and the adhesive, if necessary. The polymerization accelerator in this case is, for example, N.N-dimethylaniline, tetrahydroquinoline, triethylamine, triethanolamine, monoamine, polyamine, methylethylketone peroxide, iron sulfate, cobalt naphthenate and the like. The polymerization accelerator is preferably added within the range of 0.1 to 15% by weight with respect to the adhesive.

As the radical polymerizable resin, for example, unsaturated polyester resin, polyurethane resin, epoxy resin, acrylic resin or the like can be used. These radical-polymerizable resins are applied to the surface of the wood veneer and then pressed into the wood veneer to penetrate into the wood veneer. At the same time, the radical polymerization initiator is mixed with the radical polymerization initiator that has permeated from the side of the base veneer. Polymerization is initiated and cured by heat at the time of irradiation or by irradiation of electromagnetic waves performed later.

As the base plate, plywood, fiberboard, paperboard, particle board, synthetic resin plate, metal plate, concrete plate, or the like is used. Further, if a wood veneer having an excessively large thickness is used, it becomes difficult for the radical polymerizable resin and the initiator to permeate. Therefore, it is preferable to use a wood veneer having a thickness of 0.2 to 3 mm, preferably 0.2 to 1.2 mm.

In order to produce the surface-reinforced decorative plywood according to the present invention, a polymerization accelerator is added, if necessary, to one or more of a thermal polymerization initiator and a photosensitizer as an adhesive and a radical polymerization initiator. The mixture is applied to the surface of the base plate, a wood veneer is laminated thereon, and a radical-polymerizable resin is applied to the surface of the wood veneer. The amount of the mixture applied to the base plate surface is 80-
The amount of the radically polymerizable resin applied to the surface of the wood veneer is 200 g / m ² , and it is generally 30 to 250 g / m ² although it varies depending on the species and thickness of the wood veneer. . Then, the obtained laminate is pressed to impregnate the wood veneer with the mixture and the radical-polymerizable resin. Then 90
The adhesive is cured by heating to ~ 170 ° C, and in the wood veneer, the radical polymerizable resin that has penetrated from the front surface side and the radical polymerization initiator in the mixture that has penetrated from the back surface side are contact mixed. When a thermal polymerization initiator is used as the radical polymerization initiator, the radical polymerization is initiated by this heating, and the resin that has penetrated into the wood veneer is polymerized and cured. The pressing and heating may be performed in two steps as described above, or may be performed in one step by hot pressing. When a photosensitizer is used as the radical polymerization initiator, one or two kinds of microwaves, ultrasonic waves, light (ultraviolet rays or long-wavelength far-infrared rays of 3 to 50 μm), radiation, etc. are used after hot pressing. By irradiating the above electromagnetic waves, radical polymerization can be initiated and the resin that has penetrated into the wood veneer can be polymerized and cured.

<Operation> By heat-pressing a laminated body in which wood veneers are laminated on the surface of the base plate, the mixture of the adhesive and the radical polymerization initiator applied to the surface of the base plate is applied from the back side of the wood veneer. The wood-based veneer is impregnated with the radical-polymerizable resin applied to the surface of the wood-based veneer from the surface side. The adhesive is hardened by heat pressing to give sufficient adhesion to the wood veneer. When the radical polymerization initiator is a thermal polymerization initiator, polymerization of the radical polymerizable resin is initiated and cured at the same time when the heat compression is performed. When the radical polymerization initiator is a photosensitizer, the radical polymerizable resin is polymerized and cured by irradiating with an electromagnetic wave after hot pressing.

<Example> 90 parts by weight of an adhesive composed of SBR latex and urea-melamine cocondensate, 5 parts by weight of benzoyl peroxide as a radical polymerization initiator, and 1 part by weight of azobisisobutylnitrile as a polymerization accelerator are mixed. The mixture consisting of, is applied to the surface of the base plate consisting of polymerization at a rate of 100 g / m ² ,
A 0.5 mm thick wood veneer made of rice bran was laminated on top of this, and the radical polymerizable resin unsaturated polyester was applied to the surface of the wood veneer at a rate of 100 g / m ² . By heat-pressing the obtained laminated board at 140 ° C. for 10 minutes, a surface decorative plywood as shown in FIG. 1 was obtained. That is, this surface-decorated plywood is a coating layer made of a mixture of a radically polymerizable resin coating layer 1, a wood veneer 2, an adhesive and a radical polymerization initiator, and a polymerization accelerator if necessary, from the surface side. 3 and a base plate 4 are sequentially laminated, and a wood veneer 2
Is impregnated with the radically polymerizable resin from the front surface side and the mixture from the back surface side.

<Effects of the Invention> According to the method of the present invention, a wood veneer can be impregnated with a radical-polymerizable synthetic resin and a radical polymerization initiator in a normal plywood manufacturing process, and the synthetic resin can be polymerized and cured. No special equipment for liquid injection is required. Therefore, a decorative plywood whose surface is reinforced with a synthetic resin can be industrially manufactured within a short time, easily, inexpensively.

[Brief description of drawings]

FIG. 1 is a partial sectional view showing a schematic structure of a surface-reinforced decorative plywood manufactured by the method of the present invention. Explanation of signs 1: Coating layer of radically polymerizable resin 2: Wood veneer 3: Coating layer of mixture containing adhesive and radical polymerization initiator 4: Base plate

Claims (4)

[Claims] 1. A mixture of an adhesive and a radical polymerization initiator is applied to the surface of a base plate, a wood veneer is laminated on the coating layer of the mixture, and a radical polymerizable resin is further applied to the surface of the wood veneer. Production of a surface-reinforced decorative plywood characterized by coating and impregnating the wood veneer with the mixture and the radical-polymerizable resin, and then initiating radical polymerization to polymerize and cure the radical-polymerizable resin. Method. 2. A mixture of an adhesive and a thermal polymerization initiator that initiates radical polymerization by heat is applied to the surface of a base plate, a wood veneer is laminated on the coating layer of the mixture, and a wood veneer of the wood veneer is further prepared. After applying a radically polymerizable resin on the surface, the mixture and the radically polymerizable resin are impregnated in the wood veneer by hot pressing the obtained laminate to cure the adhesive and simultaneously heat the laminate. A method for producing a surface-reinforced decorative plywood, characterized by initiating radical polymerization by heat during compression to polymerize and cure the radical-polymerizable resin. 3. A mixture of an adhesive and a photosensitizer for initiating radical polymerization by light is applied to the surface of a base plate, a wood veneer is laminated on the coating layer of the mixture, and the wood veneer is further coated. After applying the radically polymerizable resin on the surface, the mixture and the radically polymerizable resin are impregnated into the wood veneer by hot pressing the obtained laminate to cure the adhesive, and then the electromagnetic wave is applied. Radical polymerization is initiated by irradiating the radical-polymerizable resin to polymerize and cure the radical-polymerizable resin. 4. The method according to claim 1, wherein a polymerization accelerator is added to the mixture.