JPS62225303A - Manufacture of improved woody-material small piece - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to wood strips, such as phenolic resins, which are endowed with moisture resistance, antiseptic properties, thermoplasticity, and moldability.

Thermosetting resins such as urea resin and melamine resin, thermoplastic resins such as vinyl chloride and polyester resin, and modified powders, fibers, and flakes used as fillers and raw materials for fiberboard, and as soil conditioners. The present invention relates to a method for producing wood strips.

PRIOR ART AND THEIR PROBLEMS Conventionally, it has been proposed in Japanese Patent Laid-Open No. 135552/1983 to impart thermoplasticity to wood strips and use the mixture with a resin.

However, the disclosed method of treating wood flour by bringing it into contact with a reaction liquid is industrially performed by charging wood chips into a reactor and supplying the reaction liquid to the reactor from a reaction liquid storage tank. After the reaction is completed, it is necessary to collect the reaction solution into the reaction solution storage tank for repeated use, as well as drain the excess reaction solution from the treated wood strips and wash them. The reaction liquid is easily retained between the material strips, and P
Water-based or bad. For this reason, it took time and effort to recover the reaction solution, the recovery rate of the reaction solution was low, and it also took time and effort to wash the modified wood strips after the reaction.

However, there was a risk that the fine powder of wood chips mixed in the reaction solution would clog the valve portion of the piping, thereby interfering with the operation of the valve and the like.

Furthermore, since the wood strips are bulky, they have a larger volume compared to the same weight of raw wood material. Therefore, in order to modify wood chips of the same weight, it is necessary to increase the number of operations or increase the volume of the reactor, which requires a great deal of labor and effort.
There was a problem that equipment costs were required.

On the other hand, it has been proposed in JP-A-58-174699 to use a mixture of modified wood strips and untreated wood strips, but this method requires both to be weighed. There was a problem in that the number of production steps was increased because it had to be mixed by

Structure of the Invention The present invention, as a means to solve the above-mentioned problems, involves contacting at least the surface layer of a wood raw material in the form of a plate, block, or depression with a reactant capable of reacting with the hydroxyl groups in the wood component. After chemically modifying the raw wood material, the raw wood material is cut into pieces.

Wood raw materials include wood veneers, thin boards, and small square timbers.

These include items made by cutting, cutting, cutting, or crushing small pieces of lumber, wood chips, logs, and square lumber into small pieces or chunks.

Examples of reactants that can react with the hydroxyl groups in the wood component include esterifying agents and etherifying agents, as well as isocyanates (eg, methyl isocyanate, edyl isocyanate, etc.).

Esterifying agents include organic acid anhydrides (for example, anhydrides such as acetic acid, propionic acid, butyric acid, etc.), organic acid halides (for example, in addition to the above acids, halides such as caproic acid, lauric acid, stearic acid, and methacrylic acid). , especially their chlorides), and mixtures of organic acid anhydrides and fatty acids (
Examples include mixtures of trifluoroacetic anhydride or chloroacetic anhydride, and propionic acid, caproic acid, lauric acid, etc.). These esterifying agents can be used alone or in combination of two or more.

A catalyst for promoting the reaction with the wood component and/or a solvent for promoting the penetration of the esterifying agent into the wood cell membrane may be added to the esterifying agent. Examples of such catalysts include sulfuric acid, perchloric acid, urea (ammonium sulfate), fatty acid salts, and bilinone, and examples of solvents include benzene, toluene, dimedylformamide, and dinitrogen tetroxide-nomedylformamide, and each It may be used as a seed or a mixture of more than one.

These catalysts and/or solvents may be mixed with an esterifying agent or impregnated in advance into the wood material to be treated with the esterifying agent.

Next, as the etherification agent, for example, 1.2=epoxide such as ethylene oxide and propylene oxide;
Alkyl halides such as medyl chloride and edyl chloride, aromatic halides such as benzyl chloride, dialkyl sulfates such as dimethyl sulfate, α-halogen acids such as monochloroacetic acid, and vinyl compounds activated with negative groups such as vinyl cyanide. ,
Aldehydes such as formaldehyde can be used.

In the case of an etherification agent, as in the case of an esterification agent, a catalyst (for example, an alkaline catalyst such as sodium hydroxide) and a solvent (for example, a solvent similar to that used in the case of an esterification agent) are added as appropriate. It is preferable to impregnate the wood material in advance with the etherifying agent before treating it with the etherifying agent.

In order to bring the reactant into contact with the raw wood material, for example, the raw wood material may be immersed in the reactant, or the reactant may be vaporized and the raw wood material may be exposed to this. In addition, such a method can be carried out under reduced pressure, under increased pressure, or by a forced pressure method to promote impregnation of the reactant into the wood raw material.

Chemical modification is achieved by heating the wood material together with a reaction solution and causing the functional groups in the reaction solution to react with the hydroxyl groups in the wood component. After the reaction, the remaining reaction solution is washed or removed from the wood material either directly or by neutralization, and then dried.

The degree of chemical modification depends on the presence or absence of a catalyst and the type of catalyst.

Type of reactant 1 Reaction time varies depending on the size of the wood material.

Usually, the reaction rate is based on the weight of the dry raw wood material before the reaction, and is expressed as the weight increase rate of the dry chemically modified raw wood material after the reaction treatment.

For example, when using acetic anhydride to impart thermoplasticity or meltability to the reaction solution, it is necessary to swell the crystalline region of wood with sulfuric acid or pyridine and acetylate the wood components in the crystalline region. The conversion reaction rate will be 40 to 70%.

On the other hand, even if acetic anhydride is used, in the case of no catalyst or an acetate catalyst such as sodium acetate, only the amorphous region of the wood is acetylated, so most of the hydroxyl groups in the wood components in the amorphous region are converted to acetyl groups. Even with substitution, the reaction rate is about 30%.

As mentioned above, by finding the maximum reaction rate and changing it appropriately, it is possible to adjust the approximate ratio of the chemically modified part and the untreated part in the raw wood material, so it is possible to adjust the approximate ratio of the chemically modified part and the untreated part in the wood raw material. A mixture of modified wood strips and untreated wood strips can be made.

Furthermore, because the reaction solution is reused, odor becomes a problem if excess reaction solution remains in the wood, and adhesives and other chemical reactions using the modified wood strips are difficult. In order to prevent this, the excess reaction solution is removed and recovered under reduced pressure after the reaction treatment.

Note that chemically modified wood raw materials include modified plywood and waste materials produced during the production of LVL.

Means for cutting chemically modified wood raw materials into pieces include crushing with a crusher such as a roller mill or ball mill, cutting with a cutting machine such as a flaker or shaving machine,
Crushing using a crusher such as a crusher, and fiberization using a pulper or refiner can be used.

The shape of the wood material fragments obtained by the above-mentioned fragmentation includes powder-like, fibrous-like, and flake-like fragments (shavings, thin pieces, crushed pieces, and pulverized pieces).

The uses of the modified wood strips obtained by the above-mentioned operation are the same as those of conventional untreated wood strips. A molded product with good quality can be obtained.

Further, when the treated wood strips are used as a surface layer material of particle board, water resistance and surface smoothness are improved.

Furthermore, the fiberboard obtained by paper-making the untreated wood mixed wood strips obtained by adjusting the reaction rate has excellent rot resistance and three-dimensional stability.

Example 1 3jIJ! A thick wood veneer is immersed in a 5% by weight aqueous sodium acetate solution, impregnated and dried, and this wood veneer is placed in a reaction pot, which is a reaction vessel, and a reaction mixture consisting of acetic anhydride is added to the wood veneer. The liquid is pressurized and injected, the excess reaction liquid is removed from the reaction pot, and the remaining reaction liquid is removed from the reaction vessel. After reacting at a heating temperature of 120°C for 30 minutes to modify the wood veneer, the remaining reaction liquid remains in the wood veneer. The reaction solution was deliquified and removed, and further washed and dried to obtain an acedelized wood veneer with a reaction rate (weight increase rate) of 25%. The acedelized wood veneer was then crushed using a crusher and further crushed using a ball mill to obtain acedelized wood strips having a size of +00 mesh.

In this example, it was confirmed that the collected reaction solution could be used 20 times without replenishing new reaction solution, and had an excellent recovery rate.

Example 1 was mixed with urea resin in a dry weight ratio of 1.5 times,
When molded, a molded product with a smooth surface and good moldability was obtained.

It has been confirmed that this has the same moldability as that made using 100 mesh wood flour treated with acedel, and is superior in smoothness, gloss, and whiteness compared to that made using untreated wood flour. can.

Example 2 When the reaction time of Example 1 was changed to 5 minutes, the reaction rate was 10%.
An acetylated veneer was obtained. Furthermore, +00 mesh wood flour was obtained by the same operation. When this was sorted, it was confirmed that treated wood strips and untreated wood strips were mixed together.

Effects of the Invention As is clear from the above explanation, according to the present invention, the water retention property is good in the step of removing the reaction solution, which facilitates the recovery work of the reaction solution, increases the recovery rate, and improves the reaction rate. The liquid can be used repeatedly.

Additionally, cleaning of the treated material becomes easier.

However, since fine wood particles are less likely to be mixed into the reaction solution, the piping and valves of the reaction vessel are less likely to become clogged, making maintenance easier.

Furthermore, since the raw wood material is not as bulky as the wood strips, a large amount of modified wood strips can be obtained in one operation. In particular, if only the surface layer of raw wood material is chemically modified and the reaction rate is adjusted appropriately, a mixture of modified wood chips and untreated wood chips can be obtained in one operation. This has the effect of reducing production man-hours and increasing productivity.

Claims (1)

[Claims] (1) After chemically modifying at least the surface layer of a wood material in the form of a plate, block, or chip with a reactant capable of reacting with the hydroxyl group in the wood component, the wood material is A method for producing modified wood strips, the method comprising cutting into strips.