JPH04146101A - Surface processing method of lumber product - Google Patents

Abstract

PURPOSE:To facilitate surface curing treatment by removing resin contents of pine, by a method wherein after sawing of the pine into necessary dimensions, the same is put swiftly into a pressure kiln and heating and pressurization are applied to the same by blowing live steam into the kiln. CONSTITUTION:A board material having high resin contents such as pine is loaded on a pallet swiftly after sawing and the pallet is put into a pressure kiln. A temperature rise, pressure rise and water are given to the board material within the pressure kiln. Then the kiln is made into the normal temperature and pressure by exhausting gradually. During heating and pressurization, resin contents are extracted along with water through the board material and dehydration is performed along with deresination. The board material taken out of the pressure kiln is dried and the percentage of water contents is adjusted. The finish processing such as planing and grinding by a grinder are applied to both the surfaces. Then when surface curing and polish processing are applied to a finish-processed pine by heating, pressurization and compression, the surface is cured, the grain of wood is caused to appear and glossy pine is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement in a method for treating the surface of wood, particularly for hardening, polishing, and preventing discoloration of the surface of wood products containing high resin content such as those of the pine genus. related to things.

[Prior Art] Wood, especially softwood such as pine, cedar, and cypress, is generally soft and easily scratched, making it difficult to use for floorboards and the like.

Although pine wood is somewhat harder than other softwoods, it is still susceptible to scratches.

Therefore, conventionally, these softwood materials have been subjected to material improvement through plastic processing and surface hardening treatment.

For example, vinyl monomers such as MMA (methyl methacrylate) and styrene are heated and cured, or P
A film such as P (polyethylene) or EVA (ethylene-vinyl acetate copolymer) is heat-fused to the surface, or PEG
(polyethylene glycol), etc.

However, strengthening through plastic treatment increases the specific gravity of the wood, and also increases the cost of chemicals and processing. Moreover, it significantly reduces the moisture absorbing and discharging properties and warm feel that wood has, and has drawbacks such as being susceptible to soaking when wet, and the plastic peeling off from the surface after a long period of time, making it unsightly.

[Problems to be Solved by the Invention] In recent years, paper processing methods have been developed in which only the surface layer of wood is heated and compressed to increase its surface hardness and surface gloss. This utilizes the plasticity and permanent deformation of wood due to heat, moisture, and pressure, which increases the density and strength of the surface layer of the wood. The extent of this depends on the type of wood, moisture content, and processing conditions, but it is said that the surface strength is around 10% to 40%, and the surface wear resistance is around twice as high.

However, this processing method has no problems with cedar, cypress, etc., but in the case of wood with a high resin content, such as pine, a large amount of resin oozes out onto the surface of the material due to heating and pressure, making processing difficult. This will ruin the material again. Even if you remove the tar that has oozed out from the surface with a solvent, etc., it will gradually change color due to the tar that gradually oozes out from inside. Therefore, although there is a great demand, it has not been possible to harden the surface of pine wood by heating and pressurizing it.

Therefore, the present inventor focused on the tar content of pine wood, and as a result of intensive research, succeeded in removing the tar content from pine wood and surface hardening treatment by heating and pressurizing.

[Means for solving the problem] There are many types of pine, including district pine (red pine, black pine, etc.), rainbow pine, rice pine, new sealant pine, etc., but all of them contain resin (pine resin) in their wood. Contains. The resin content is broadly divided into oily terpenes and solid resin M (commonly known as rosin).As time passes, resin content oozes out onto the product surface, and the color gradually changes from brown to dull black. , there are drawbacks that lower the product value. When drying in the sun, this kind of phenomenon occurs to a greater or lesser extent.

It is not possible to remove the tar that has hardened on the surface of the wood, and the only way to remove the discoloration is to bleach it with bleach, but bleaching loses the wood's natural characteristics and weakens the quality of the wood.

Therefore, the inventor of the present invention sawn pine wood to the required dimensions, immediately put it in a pressure cooker, and heated and pressurized it by blowing live steam into it. As a result, the resin content in the pine wood was removed to the extent that there was almost no discoloration later on. succeeded in doing so.

I used a horizontal tank-type pressure cooker with several perforated pipes for blowing out live steam inside, but if it is a closed type that can store wood and supply heating and live steam, then It doesn't matter what you want.

The resin removal process depends on the type of product (board, hollow wood, square timber, straight grain or board, etc.) and dimensions (particularly thickness), but at a temperature of about 100 to 130 degrees Celsius, and at zero temperature. .5-1.5K
A pressure of about gf/- is applied for about 3 to 8 hours, depending on the case, over a day and a night.

In the case of normal plate materials, the temperature is 115 to 130°C, preferably about 120 to 125°C, and 0.8 to 1.5°C.
Kgf/cd, preferably 1.0 to 1.4 Kgf/
The pressure is applied for about 3 to 8 hours.

Among these, it is preferable to slowly increase the temperature and pressure over a period of about 1 to 2 hours, and to slowly decrease the temperature and pressure over a period of about 1 hour.

In the case of straight wood boards, warping and cracking are less likely to occur, so somewhat harsh conditions are acceptable. If the thickness is about 10 m or 201 Ill, tar can be completely removed by this level of treatment.

For products that are thick and have a high risk of cracking or deforming, such as thick plates or square timbers, especially pillars, apply a pressure of 0.5 to 1.3 K.
It is preferable to carry out gradually over a long period of time (for example, 8 hours or more or 1 day and night) under gentle conditions of gf/cd and a temperature of about 105 to 115°C. This is to prevent cracking and deformation due to drastic changes in temperature and humidity. In this case, the temperature and pressure are increased for about 2 to 3 hours, and after this state is maintained for several hours, the air is gradually evacuated to bring the temperature and pressure to room temperature. However, in the case of structural materials such as pillars, care must be taken as removing too much resin will weaken the material.
If the resin is removed to a depth of about mm, there will be little discoloration over time and little deterioration in strength, so the degree of resin removal is controlled by adjusting the temperature, pressure, and time.

The reason why resin removal is carried out immediately after sawing is that the seepage of tar components on the surface of the material and color development proceed immediately after sawing. Also, as logs in storage dry, they gradually change color from the end of the log to the inside.

- Since discolored components cannot be removed from discolored wood even by removing tar according to the present invention, it is necessary to keep the log constantly moist by immersing it in water or spraying it with water to prevent discoloration.

By the way, in the above-mentioned resin removal treatment, the wood is also dehydrated when the wood is opened. Normally, the moisture content of wood products immediately after sawing is 50.
It is about ~60%, but after the tar removal process this is ~20~
It will be about 30%. The condensed water and steam extracted from the wood become a black, smooth waste liquid that contains tar and a small amount of lignin and volatile components, and is discharged from the pressure cooker.

Next, it is further dried to a moisture content of about 10 to 13%. This is because permanent compression strain is less likely to occur if the water content is high in the next heating, pressurizing and compression process.

Drying may be natural drying such as air drying or sun drying, or artificial drying using various heat sources in a dryer. - Once the tar is removed, there will be no discoloration due to drying or subsequent aging. After drying, finishing treatments are applied depending on the wood product, such as cutting the surface with a plane, finishing with a grinder, or cutting.

The pine wood product that has gone through each of the above treatment steps is passed through a pressure roller to compress the surface. The pressure roller is small (and one of them is a heating roller, the temperature of which is 150 to 230℃,
Particularly preferred is about 190 to 210°C. The pressing force (compressive force) is controlled by the spacing between the upper and lower rollers, and is approximately equal to 8 of the product thickness.
It should be about 5 to 95%. The greater the pressure and the higher the temperature, the greater the strength and gloss of the surface layer of the product, but if the conditions are too harsh, cracks or discoloration will occur, so the above range is desirable. As mentioned above, since compressive strain is less likely to occur if the moisture content of the product is high, the moisture content of the wood product should be about 10 to 13%.

This heating and pressure compression causes the wood grain to stand out on the surface of the wood product that comes in contact with the heated roller, and the pressure and heating of some remaining lignin creates a beautiful gloss, and the surface condition is similar to that before processing. It changes completely. Wall materials, etc., have a more subdued luster even without the use of varnish, etc., and in the case of floor materials, there is a bar and the wood grain plays a role in preventing slipping, making it extremely easy to use. . In addition, if a dye or pigment is applied to the surface of the product before heat and pressure treatment, various colors can be applied, such as colors for high-quality materials or reddish colors for white materials. Partial discoloration and color variations can be covered by coloring.

However, when pine wood products subjected to the above-mentioned heating, pressure and compression treatment come into contact with water, they tend to lose their surface hardness and grains due to water absorption. Also, like other wood products, it has the disadvantage of being prone to stains. This is particularly a problem in the case of flooring. Therefore, in order to eliminate such defects, after the above treatment, a thin layer of surface treatment agent such as natural oil-based material (for example, a bending material derived from vegetable oil or a mixture of wax and coloring agent dissolved in a solvent) is applied. This improves its water resistance and water repellency while maintaining its moisture absorption, texture, and other qualities of wood, and when it is polished with a puff or motsup, it becomes beautiful.

The coloring in this case serves the same purpose as the staining solution described above.

On the other hand, when the surface of pine laminated wood is heated and pressurized to harden and polish the surface, the bonded area is difficult to compress, so streaks appear and reduce the product value. Therefore, after first applying various treatments such as removing resin, drying, and hooking to the square timbers and assembling them, at least one side is lightly applied with a heated pressure roller (about 1/3 to 2/3 of the time used for polishing). After applying pressure to make the bonded portion protrude, the surface may be smoothed again by planing, and then compressed with a predetermined pressure to harden and polish the entire surface. In addition, when pasting pine boards or sliced products onto the surface of laminated wood (any type of wood), the side of the laminated wood to be pasted must be subjected to pressure compression treatment and smoothing treatment such as plane finishing in advance. If you leave it in place, the surface of the product will have stripes that originate from the joints of the laminated wood, giving it a beautiful finish.

[Example J Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A large number of Japanese pine planks sawn to a width of 10 cm, a thickness of 12 cm, and a length of 4 m are immediately loaded onto pallets via vertical crosspieces (19 mm square), and the pallets are placed in a pressure cooker. .

A pressure cooker is a horizontally long cylindrical vessel, with several perforated vibrators placed around the inside of the cooker to blow live steam into it to increase temperature, pressure, and moisture. Temperature and pressure increase is 6
Gradually over 0 minutes, increase gf/ to 120℃ and 1.3
Maintain the cj state for about 2 hours.

Thereafter, the chamber was gradually evacuated over 60 minutes to bring it to normal temperature and pressure.

During heating and pressurization, black color S (stain content, etc.) is extracted from the board together with water, and dehydration is performed along with removal of tar.

No warpage or cracks were observed in the wood from which the resin had been removed. The moisture content of the board was approximately 25%.

The plate material taken out from the pressure cooker was further placed in a steam-heated dryer and dried for 2 to 3 days to reach a moisture content of 10%.

Next, finishing processes such as planing and grinding on both sides, and finishing on the mating surfaces were performed.

Next, the finished pine board material was subjected to surface hardening and polishing by heating and pressing. The heating and pressurizing was carried out by passing through a set of pressure rollers having a diameter of about 30 cm+ and a width of about 40 cm+1. The upper heating roller is approximately 2
It is heated to 0.5℃, and the distance between the upper and lower rollers is 10.
It is adjusted to 8mm (compression rate 90%). Further, the feeding speed was 1 m/min.

In this way, the surface was hardened and a board material with cracks was obtained.

Example 2 A large number of Japanese pine poles sawn to approximately 12 cm square (4 cm square) and 3 m long were loaded onto pallets via crosspieces above and below, and the pallets were placed in a pressure cooker and treated with resin in the same manner as in Example 1. It was drained and dehydrated. The conditions were: 110 degrees Celsius at about 3 o'clock.
The temperature and pressure are increased to 1.2Kgf/-. In this state, when the steam is turned off and the device is left overnight, the temperature and pressure gradually decrease, and the temperature and pressure in the chamber reach normal pressure after the valve is opened at about 16:00. During this time, the black pigment (
Tar, etc.) are extracted along with water, and dehydration is performed along with removing tar. No cracks were observed in the pillar material that had been removed from tar, and the tar up to about 71III11 had been removed from the surface. The moisture content of the pillar material was approximately 25%. The pillar material taken out from the pressure cooker was further air-dried for about two months to bring the moisture content to approximately 12%. Then,
Finishing was done by planing on all four sides and polishing with a grinder.

Next, all four sides of the finished pine post material were subjected to surface hardening and polishing by heating and pressing. In the apparatus of Example 1, heating, pressure and compression were performed using both the upper and lower rollers at 200 mm.
The test was carried out by heating to ℃. The distance between the upper and lower rollers is 10.2
cm (compression rate 85%), and the feed rate was In/min. In this way, the surface of all the surfaces was hardened, and a pine post material with ribs was obtained.

Example 3 A white pine board with the same dimensions as in Example 1 was subjected to various treatments similar to those in Example 1, and then a reddish dyeing solution (aqueous neo-power, 200 times diluted) was applied to one side. It was air-dried for about 5 hours.

Next, the dyed surface was subjected to the same heating, pressurizing and compression treatment as in Example 1 to obtain a board material with an excellent appearance and a reddish color similar to that of the core material.

Example 4 In Example 1, a pine-colored OS color (distributor: Sunmore Tsusho) was applied as a surface treatment agent (waterproofing and polishing agent) to the surface of the plate material that had been finally subjected to heat and pressure compression treatment. )
was applied at a rate of 15 to 20 cc/r+f, and then the surface was puff-finished. With this finish, it has a calmer color than the original polish, a woody texture, and moisture absorption and drainage properties.
Moreover, a board material with water repellency was obtained. This OS color is a mixture of oil columns derived from vegetable oils and colorants.
% dissolved in 30% alcohol.

Example 5 Test plates with a width of 40++u++ and a thickness of 13 mm that were finished in the same manner as in Example 1 were assembled to form a test plate with a thickness of 40 mm and a width of 12 mm.
A laminated timber of 0IIIll was obtained. This laminated wood was pressurized and compressed in the same manner as in Example 1 (roller gap 3B++v+: compression rate 95%), and then the protruding bonded parts were planed and smoothed. Next, the gap between the rollers was adjusted to 345 mg (compression rate: 85%), and the material was heated and compressed again to obtain a laminated wood whose surface was hardened and polished on one side.

[Effects of the Invention] As described in detail above, the present invention allows wood containing a high resin content, such as wood of the pine genus, to be immediately put into a pressure cooker after being sawn, removed with steam and dehydrated, and then dried and planed. After finishing the material, it is passed through a heated pressure roller to prevent discoloration over time due to tar, and at the same time harden and polish the surface.

Therefore, it is possible to easily and reliably process pine wood products, which were previously difficult or impossible to polish and surface harden by heating, pressurizing and compressing, and there is no discoloration over a long period of time.
This contributes greatly to the high quality and versatility of pine wood. Moreover, since no chemicals are used to remove tar, it is safe and has advantages such as low cost.

In addition, for decorative laminated lumber made of pine laminated lumber or various types of lumber laminated lumber with inspection boards or slices pasted on the surface, it similarly has the effect of easily and reliably hardening the surface, polishing it, and preventing discoloration.

Claims (1)

[Scope of Claims] 1. Immediately after sawing, high-resin-containing wood such as Pinus wood is placed in a pressure cooker to remove tar and dewater with steam, and then further dried, followed by finishing treatment such as planing. A method for surface treatment of wood products, which comprises passing at least one side of the wood product through a heated pressure roller to harden and polish the surface. 2. After applying various treatments such as removing tar, drying, planing, etc. to the square timbers of high resin content wood such as pine and assembling them, at least one side is lightly compressed with a heated pressure roller to seal the bonded parts. A method for surface processing a wood product, which comprises protruding the surface, smoothing the surface again, and then compressing with a predetermined pressure to polish the entire surface. 3. Claim 1 or Claim 2, wherein a dyeing solution is applied to the surface of the wood product before passing it through a heated pressure roller.
Surface treatment method for wood products described. 4. Surface treatment of a wood product according to claim 1 or claim 2, wherein the surface of the wood product is hardened and polished using a heated pressure roller, and then a surface treatment agent is applied to the surface of the wood product to give a puff finish. Method.