JPH0569414A - Manufacture of lumber improved in its incombustibility and dimensional stability - Google Patents

Abstract

PURPOSE:To simply obtain an improved lumber with good incombustibility and dimensional stability by applying and subsequently drying the salt or compound of a basic nitrogen compound and phosphoric acid on the surface of lumber, and thereafter inserting and then heat-treating it into the hot plates of a hot press. CONSTITUTION:A compound consisting mainly of the salt of basic nitrogen compound and phosphoric acid (e.g. phosphoric guanidine, dicyandiamide- formaldehyde-phosphoric acid) is applied, and then impregnation-dried, on the surface of lumber, following this, it is inserted into hot plates of a hot press of 100-200 deg.C, furthermore, heat-treatment is effected thereto under the condition of 3-25kg/cm<2>, and 3-30mins.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to flame retardation and dimensional stabilization of wood or wood materials (hereinafter referred to as wood).

[0002]

2. Description of the Related Art Conventionally, in order to improve the properties of wood such as flammability and fragility, a flame-retardant compound containing elements such as phosphorus, boron, nitrogen, and halogen,
A method of impregnating or injecting a dimensional stability-imparting compound such as polyethylene glycol or polyethylene glycol monomethacrylate into the inside of the wood by a pressure reduction method, a diffusion method, or the like, and then heating or drying or curing the method. well known.

[0003]

However, the method of impregnation and injection requires a large amount of chemicals and time, and
It is not easy to make a drug penetrate into the wood. Furthermore, a great deal of time and energy are required for the heat drying or curing process after impregnation and injection.

In Japanese Patent Laid-Open No. 1-267001, a surface compact is prepared by feeding a material to be treated coated with a thermosetting resin between a plurality of sets of heat and pressure rolls and subjecting the surface layer of the material to be hardened. Although a treated wood and a method for continuously producing the same are disclosed, the above-mentioned method using a hot pressure roll is difficult to provide sufficient energy to carry out the intended surface treatment, and the flame retardancy of the treated material is low. In addition, the improvement of dimensional stability is not satisfactory.

The present invention is flammable, which is a drawback of wood,
The present invention provides a method for producing improved wood (hereinafter referred to as improved wood) having flame retardancy and dimensional stability by improving the property of being prone to misalignment by a phosphoric acid esterification reaction on the surface layer of wood. Here, the phosphoric acid esterification refers to a reaction involving a dehydration reaction in a reaction between a hydroxyl group such as cellulose contained in wood and phosphoric acid, which is 100 ° C. or higher regardless of the state of wood. Temperature is required continuously.

[0006]

Means and Actions for Solving the Problems The present invention relates to the heat of a hot press in which the temperature of the wood to which the compound containing a salt of a basic nitrogen compound and phosphoric acid as a main component is added is set to 100 to 200 ° C. Insert between the plates, then pressure 3-25Kg / cm ² ,
A method for producing wood with improved flame retardancy and dimensional stability, which comprises subjecting the surface layer of the wood to a phosphoric acid esterification reaction under heat and pressure treatment for 1 to 30 minutes.

As the basic nitrogen compound in the present invention, urea, dicyandiamide, melamine, guanidine, monoethanolamine, diethylenetriamine, aniline, N, N-dimethylformamide, acetamide, etc., or a mixture thereof, For resinification and solidification in the wood surface layer and inside, it may be a methylol compound or an initial condensate obtained by reaction with formaldehyde such as formalin, dioxane, and paraformaldehyde, for example, an initial stage of dicyandiamide and formaldehyde. It may be used as a compound such as a condensate or an initial condensate of a mixture of melamine and dicyandiamide and formaldehyde.

[0008] The conditions of hot pressing are sufficient as long as they cause phosphoric acid esterification on the surface layer of the wood, but as mentioned above, phosphoric acid esterification requires a temperature of 100 ° C or higher continuously. On the other hand, treatment at high temperature, high pressure, and long time causes discoloration, deformation, deterioration and the like of the wood, which is not preferable. Preferable heat and pressure treatment conditions vary depending on the condition of the wood to be treated such as tree species, shape, size, water content, etc., but generally, temperature is 130 to 180 ° C., pressure is 8 to 15 Kg / cm ² , and time is 5 to 15 minutes. Is suitable.

It is well known that the introduction of nitrogen and phosphorus into a material mainly composed of cellulose such as wood or cotton cloth improves the flame retardancy. This is because the formation of a carbonized layer in the carbonaceous material is promoted, and the addition of the compound containing the salt of the basic nitrogen compound and phosphoric acid as the main component to the wood is not advantageous in terms of formation of the carbonized layer. It is not necessary to penetrate to the inside, and it is also achieved by surface application to the wood.

The present invention is intended to selectively cause a phosphoric acid esterification reaction on the surface layer of wood to impart flame retardancy and dimensional stability to the wood. However, a strong acid such as phosphoric acid is used. Addition to wood also contributes to deterioration of wood. However, the basic nitrogen compound not only serves as an acid buffer which is one factor that deteriorates wood,
It also serves as a catalyst when the esterified product is formed by the reaction between phosphoric acid and a hydroxyl group such as cellulose.

Further, by heat-pressing the wood to which the above compound is added, a large amount of energy is efficiently and uniformly applied to the surface layer of the wood, so that the above phosphoric acid esterification reaction is not only promoted. Without the hot-pressing treatment, the water in the wood and the water generated by the esterification reaction are superheated to serve as an expansion medium for the wood and serve as a transfer medium for the compound into the cells of the wood,
It accelerates the phosphoric acid esterification reaction not only on the surface layer of wood but also inside the wood. The heat and pressure treatment is generally performed by inserting a material to be treated between hot plates heated by steam or the like and treating it in a state of being in close contact with the hot plates, and the reaction system is a closed system in which water or the like is hard to escape. Therefore, the above-described actions and reactions are promoted.

Further, when the wood is hot-pressed, the components such as hemicellulose in the wood, which are easily decomposed by heating, are decomposed and the crystallization of the cellulose is promoted, which synergizes with the above phosphoric esterification. The effect improves the dimensional stability of the wood.

Therefore, in the method by the hot pressure roll as disclosed in Japanese Patent Laid-Open No. 1-267001, the energy for esterification reaction and superheated vaporization of water as a medium is not sufficient, and The simultaneous provision of flame retardancy and dimensional stability to wood, which is the object of the invention, is not preferable from the viewpoint of thermal efficiency.

[0014]

【Example】

Examples 1, 2, 3 and Comparative Examples 1, 2, 3 Guanidine phosphate (P / G = 1/2, mol) as a compound containing a salt of a basic nitrogen compound and phosphoric acid as a main component,
Phosphoric acid dicyandiamide (P / D = 1/1, mol) and urea phosphate (P / U = 1/1, mol) were added to distilled water in Table 1.
The treatment solution adjusted to have the respective impregnation rates as shown in Fig. 5 is applied and impregnated on a 5 mm-thick Burswood veneer,
The impregnation rate after air drying was adjusted to about 10%, 20%, and 30%, and the treated material was inserted between the hot presses set at a temperature of 160, and then heated at a pressure of 10 Kg / cm ² for 15 minutes. Pressure treatment was performed to obtain the improved wood of Examples 1, 2, and 3. Also,
For comparison, Comparative Examples 1, 2 and 3 were obtained by heating the treated material having the impregnation rate after air drying adjusted to about 20% in a hot air dryer set at a temperature of 160 ° C. Next, JIS A 1
Flame retardancy (carbonization length: cm) by the test method of 322, 4
The anti-swelling ability (Anti Swelling Efficity) was maintained by leaving it in a thermo-hygrostat set to 0 ℃ -30% RH and 40 ℃ -90% RH.
The dimensional stability was evaluated by iency: ASE:%). The measurement results are shown in Table 1.

[0015]

[Table 1]

Examples 4, 5, 6, 7 and Comparative Example 4 1 mol of 37% formalin as formaldehyde was added to 1 mol of dicyandiamide, and water was added so that the solid content after the reaction was 30%. The resulting solution was reacted under reflux and then cooled to 50 to 60%, then 0.5 mol of 85% phosphoric acid aqueous solution as phosphoric acid was added and stirred to give a treatment solution consisting of dicyandiamide-formaldehyde-phosphoric acid. Obtained. Then, the above treatment solution was added to a 5 mm-thick burswood veneer by coating or dipping so that the impregnation rate (%) shown in Table 2 was obtained, air-drying, and then hot pressing at a temperature of 160 ° C. Insert between the hot plates,
Heat-pressed treatment was carried out under the conditions of a pressure of 10 kg / cm ² and a time of 10 minutes to obtain improved woods of Examples 4, 5, 6 and 7. In addition, as a comparison, Comparative Example 4 was prepared by subjecting the treated material whose impregnation rate after air drying was adjusted to 15.7% to heat treatment with a hot air dryer set at a temperature of 160 ° C. Next, flame retardancy and dimensional stability were evaluated in the same manner as in Example 1, and the results are shown in Table 2.
Shown in.

[0017]

[Table 2]

Example 8 and Comparative Example 5 The treatment solution used in Example 4 was adjusted to a impregnation rate of 30% by pressure and pressure impregnation on a 20 mm-thick burswood veneer, and the air-dried treated wood was subjected to temperature control. The wood was inserted between hot press hot plates set at 160 ° C. and heat-pressed under the conditions of a pressure of 10 kg / cm ² and a time of 15 minutes to obtain improved wood of Example 8. Further, as a comparison, the above wood to be treated was subjected to hot air heat treatment in the same manner as in Comparative Example 1 to obtain Comparative Example 5. Next, JIS A 1
Flame retardance (surface temperature 10
Table 3
Shown in. The ASE of the treated wood was as good as 53%.

[0019]

[Table 3]

[0020]

EFFECTS OF THE INVENTION The improved wood obtained by the method of the present invention relates to flame retardancy of wood, as shown in Examples, in which the phosphoric acid esterification of the surface layer is selectively promoted uniformly by hot pressing. It promotes the formation of a carbonized layer on the surface layer of wood and improves the flame barrier performance.

Furthermore, according to the present invention, the disadvantages such as the tendency of wood to be easily burned and misaligned are simultaneously improved.
Since it can be improved by easy means such as coating as shown in FIG. Does not require large amounts of flame retardant resin or energy.

Claims (2)

[Claims] 1. A wood or wood material to which a compound containing a salt of a basic nitrogen compound and phosphoric acid as a main component is added,
Insert between hot plates of hot press set at temperature 100-200 ℃, then pressure 3-25Kg / cm ² , time 1-30
A process for producing improved wood having improved flame retardancy and dimensional stability, which comprises subjecting the surface of the wood or woody material to a phosphoric esterification reaction by heat-pressing under the conditions of minutes. 2. The method for producing a wood having improved flame retardancy and dimensional stability according to claim 1, wherein the compound containing a salt of a basic nitrogen compound and phosphoric acid as a main component is added by coating.