JPH10278013A - Manufacture of woody board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the formaldehyde discharge amount to the specified amount or less and improve mothproofness and mildewproofness by adding borax or boric acid mothproofing and mildewproofing agents to a formalin bonding agent for a woody board. SOLUTION: As borax or boric acid used as a mothproofing agent or a mildewproofing agent is provided with the low solubility in water, a borax or boric acid reaction compound is used instead. The solubility of the reaction compound is approximately 25 %, and the reaction compound as a boric acid water solution of higher concentration is added into a bonding agent to prevent the lowering of the concentration of the bonding agent. First, a water solution of odorless urea resin bonding reaction compound is added and agitated sufficiently. The bonding agent is added to particle board surface layer chips and particle board inner layer chips respectively, at the ratio, for example, of 12% and 8% respectively as the resin solid contents. Chips are hot-pressed to manufacture a particle board. Thus a woody board of formaldehyde discharge amount of 1.5 mg/l or less is manufactured by adding borax or boric acid mothproofing and mildewproofing agents to a formalin bonding agent for the woody board by the arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
(Abbreviated PB), fiber board (abbreviated FB),
Furthermore, the present invention relates to a method for producing a wooden board such as plywood, and to a method for producing a wooden board which emits a small amount of formaldehyde.

[0002]

2. Description of the Related Art In recent years, the problem of environmental pollution has been greatly addressed by formaldehyde generated from building materials using wooden boards, and the development of wooden boards that emit less formaldehyde is strongly desired. . The living environment improves when the emission of formaldehyde decreases,
Deterioration of insect repellent performance and mold repellency becomes a new problem. Formaldehyde emission specified in JIS standard for formaldehyde emission such as PB and medium fiberboard (MDF), JISE ₂ (formaldehyde emission 5.0 mg / l or less) and JAS standard for formaldehyde emission for plywood, JAS F ₂ When the concentration was 5.0 mg / l or less (method for measuring the concentration in water using a desiccator), insect and fungicide performance was expected. However, the amount of formaldehyde released from the wood board is 1.5 mg / l or less, especially JIS.
E ₀ and JAS F ₁ (formaldehyde emission 0.5
(mg / l or less), the effect of formaldehyde on the human body in the living environment was reduced, but the insecticidal and mold-proof performance of formaldehyde could not be expected.

Although a method of adding an insect repellent and a fungicide to the above-mentioned adhesive for producing a wood board has been considered, the toxicity of organic phosphorus repellents and organic fungicides which are generally used at present is based on formaldehyde. Many are stronger than their toxicity. The organic insect repellent / antifungal agent is decomposed during the process of hot-pressing a wooden board at a high temperature to reduce its efficacy. And MDF and PB
If a pre-cured layer on the surface of such a wooden board is polished with a sander, there is a risk that the sand dust mixed with the insect repellent and the fungicide is absorbed by the human body. Further, chlorine and other halogen compounds contained in the organophosphorus insecticide and the organic fungicide have a problem that there is a risk of generating dioxin or a harmful substance having a structure similar to dioxin during combustion.

[0004]

Means for overcoming the above-mentioned drawbacks A wood board obtained by applying a formalin-based adhesive to wood chips, wood chips or wood fibers to form a mat and hot-press molding to a predetermined thickness;
For example, PB, FB, OSB (Oriented str)
plywood, LVL (single-ply laminate), LVB (single-ply laminate) obtained by laminating a plurality of veneers with a formalin-based adhesive therebetween and hot-press bonding. ) A method for producing a wood board, comprising: adding a borax-based or boric acid-based insect / mildew-proofing agent to the formalin-based adhesive, wherein the formaldehyde emission amount is 1.5 mg / l or less. Provided is a method for manufacturing a semiconductor device. Further, the present invention provides a method for producing a woody board having a formaldehyde emission amount of 1.5 mg / l or less by further adding a curing accelerator to the above-mentioned adhesive containing the insect repellent / antifungal agent.

When borax and boric acid are used as insect repellents and fungicides, the solubility of borax and boric acid becomes a problem. Originally, the solubility of borax and boric acid in water is about 4 to 5%. Therefore, if a large amount of borax or boric acid is dissolved in water and added to the adhesive for the purpose of improving insect- and mold-proof performance, the concentration of the adhesive decreases. When a low-concentration adhesive is used in the production of a wooden board, poor adhesion or a puncture phenomenon occurs. As described above, since the solubility of borax and boric acid in water is low, the use of a reactive compound for borax and boric acid (Folrealo (manufactured by Enikem Corporation)) has a solubility of about 25%, which is about 5 times the solubility of borax and boric acid. Get higher. Therefore, when the same addition amount is added to the adhesive, the foliarello produces a boric acid-based aqueous solution with a higher concentration, so that even if the foliarello aqueous solution is added to the adhesive, the decrease in the concentration of the adhesive can be reduced. Since the above foliarello aqueous solution exhibits weak alkalinity, it is expected that the pot life of the formalin-based adhesive can be extended and that the adhesive can be prevented from being pre-cured.

When a wood board is produced by adding a curing accelerator such as foliarello and ammonium chloride as an insect repellent and a fungicide to a formalin-based adhesive, the curing accelerator of the adhesive can be expected more, The time is reduced. Suitable examples of the curing accelerator include salts of strong acids and weak alkalis such as ammonium nitrate and ammonium sulfate, and esters of fatty acids and lower alcohols such as acetic acid and ethyl alcohol and formic acid and methyl alcohol. As the formalin-based adhesive, an aqueous adhesive of an amino resin such as a urea resin, a urea melamine co-condensation resin, a melamine resin or a urea phenol co-condensation resin is suitable.

[0007]

According to the first aspect of the present invention, the formaldehyde emission is small, the influence of the human body is small, and the action of borax, boric acid or a reaction compound thereof is effective in controlling insects on woody boards.
Increases mold resistance.

[0008]

EXAMPLES Examples of the present invention will be described in detail along with comparative examples.

Example 1 10 parts by weight of a 20% aqueous solution of foliarello was added to 100 parts by weight of an odorless urea resin adhesive having a fat content of 60% and stirred well. The adhesive was added to a PB surface layer chip having a water content of 5% in a resin solid content of 12%. This adhesive was added to a chip for PB inner layer having a water content of 5% in terms of resin solid content by 8%. A 12 mm particle board (JIS E ₁ ) having a specific gravity of 0.72 was produced by hot pressing at 165 ° C. and 25 kg / cm ² for 4.5 minutes.

EXAMPLE 2 20 parts by weight of a 20% aqueous solution of foliarello was added to 100 parts by weight of an odorless urea resin adhesive having a resin content of 60%, and the mixture was thoroughly stirred. 5% moisture content of this adhesive
12% in terms of resin solid content was added to the PB surface layer chip. 20% for 100 parts by weight of odorless urea resin adhesive with resin content of 60%
20 parts by weight of a foliarello aqueous solution and 5 parts by weight of a 20% ammonium chloride aqueous solution were added and stirred well. This adhesive was added to a PB inner layer chip having a water content of 5% in a resin solid content of 8%. 12mm particle board with specific gravity of 0.72 at 165 ° C and 25kg / cm ² for 4 minutes (JIS
E ₁₎ it was made.

Example 3 To 100 parts by weight of an odorless urea resin adhesive having a fat content of 60%, 20 parts by weight of a 20% aqueous solution of foliarello and 2 parts by weight of a 20% aqueous ammonium chloride solution were added and stirred well. The adhesive was applied to fibers above the fiber saturation point. The adhesive was added at a resin solid content of 15% based on the fiber-dry weight. The fiber to which the pre-mixed adhesive has been added is passed through a flash dryer to a water content of 15%, formed, inserted into a hot press at a temperature of 200 ° C. and a pressure of 25 kg / cm ^2.
For 3 minutes to produce an MDF (JIS E ₁ ) having a set thickness of 7 mm and a set specific gravity of 0.75.

Comparative Example 1 A 20% aqueous ammonium chloride solution was added to 100 parts by weight of an odorless urea resin adhesive having a fat content of 60%.
5 parts by weight of 20 parts by weight of hexamethylenetetramine water was added thereto, and the mixture was stirred well. The adhesive was added to a PB surface layer chip having a water content of 5% in a resin solid content of 12%. Fat content 60
5 parts by weight of a 20% ammonium chloride aqueous solution was added to 100 parts by weight of the odorless urea resin adhesive of 100% by weight and stirred well. This adhesive is applied to a PB inner layer chip with a water content of 5% and a resin solid content of 8%.
Was added. 12mm particle board with specific gravity of 0.72 at 165 ° C and 25kg / cm ² for 4 minutes (JIS
E ₁₎ it was made.

Comparative Example 2 Double parts of a 20% aqueous solution of hexamethylenetetramine and double parts of a 20% aqueous solution of ammonium chloride were added to 100 parts by weight of an odorless urea resin adhesive having a fat content of 60%, and the mixture was thoroughly stirred. The adhesive was applied to fibers above the fiber saturation point. The adhesive was added at a resin solid content of 15% based on the fiber-dry weight. The fiber to which the blended adhesive was added was passed through a flash dryer to a water content of 15%, then formed, inserted into a hot press, and placed at a temperature of 200 ° C. and a pressure of 2 ° C.
It was heated and pressed at 5 kg / cm ² for 3 minutes to produce an MDF (JIS E ₀ ) having a set thickness of 7 mm and a set specific gravity of 0.75.

Each of the test pieces of Examples 1 to 3 and Comparative Examples 1 and 2 was subjected to a fungicide test according to JIS Z2911 mold resistance test method, and the results were as shown in Table 1 below.

[0015]

[Table 1]

Further, the test pieces of Examples 1 to 3 and Comparative Examples 1 and 2 were each subjected to JWPA standard No. 11 comprehensive test (no weathering operation), and the results are shown in Table 2.

[0017]

[Table 2]

[Discussion] As is apparent from the results of Tables 1 and 2, the wood board made by adding and mixing the borax / boric acid-based insect repellent and fungicide of Examples 1 to 3 with the adhesive. With respect to the test piece, the degree of mold development was negative, that is, no mold erosion was observed, and the weight loss rate was small. On the other hand, the test pieces of woody boards made by adding the borax / boric acid-based insect repellent and the fungicide of Comparative Examples 1 and 2 to the adhesive were positive for the degree of mold development, that is, the mold erosion was considerable. Seen,
The rate of weight loss was also high.

[0019]

According to the first aspect of the present invention, the amount of formaldehyde released from the manufactured wooden board is considerably reduced, but the insecticide and fungicide, which has been conventionally proposed, can be expected to be greatly improved. became. According to the second aspect of the present invention, in addition to the above-described effects, it is possible to further expect a further reduction in the heat pressure time.

Claims (2)

[Claims] 1. A particle board or fiber obtained by applying a formalin-based adhesive to wood chips or wood fibers to form a forming mat and hot-press molding to a predetermined thickness.
A method for producing a wood board such as a plywood board obtained by laminating wood boards such as a board or a plurality of veneers with a formalin-based adhesive therebetween and hot-press bonding. A method for producing a woody board having a formaldehyde emission of 1.5 mg / l or less, characterized in that a borax-based or boric-acid-based insect / mold inhibitor is added to a formalin-based adhesive for a board. 2. A method for producing a wooden board according to claim 1, wherein a curing accelerator is added to said compounded adhesive.