JP2006205653A - Reinforced wood impregnated with resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforced wood which retains inherent advantages of wood such as aqueous respiratory properties, is free from adverse effects and toxic influences upon health caused by an organic solvent or an unreacted chemical substance, does not produce a poisonous gas in a fire, is extremely safe from a viewpoint of health and environments, and retains the advantages of a natural wood and a strength equivalent to a conventional reinforced wood. <P>SOLUTION: This reinforced wood is manufactured by impregnating a temporary wooden conduit or a wooden conduit of pine or cedar with a water-soluble cellulose polymer derivative and drying/hardening it. The water-soluble cellulose polymer derivative to be used is a methyl cellulose (MC), a hydroxypropylmethyl cellulose(HPMC), a hydroxyethylmethyl cellulose (HEMC) or their mixture. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a reinforced wood obtained by impregnating a temporary wood conduit or a conduit with a water-soluble cellulose polymer derivative and drying and solidifying it. More specifically, the present invention relates to a reinforced wood obtained by vacuum-impregnating a water-soluble cellulose polymer derivative into a minute gap in wood, particularly a temporary conduit or a conduit, and drying and solidifying this.

There is a lot of moisture in the raw wood. It is well known that wood containing a lot of moisture cannot exhibit its original strength as wood and has problems of warping and cracking. These warps and cracks are not limited to just the strength and dimensional stability of wood, but also cause problems such as floor noise, difficulty in opening and closing of joinery, and cross cracks.
The simplest method for solving this problem is drying of wood.
Drying wood not only removes moisture from the wood, but also makes it a moisture condition where the moisture content of the wood does not fluctuate significantly and expansion and contraction are minimized under the conditions used for the product. It is aimed.
Moisture in wood can be divided into two types: “bound water” chemically bound to wood cells and “free water” that is physically and simply contained. The expansion and contraction of wood is mainly caused by “free water” contained in the wood. The presence of “free water” not only causes a decrease in the strength of wood, warpage / twisting, a decrease in the holding power of nails and bolts, but also causes decay.
The so-called equilibrium water content (water content = (wood weight-completely dry weight) / completely dry weight) that eliminates the entry and exit of water, especially free water, with respect to the external environment is determined by the relative humidity with the environment, but its value is roughly It is said to be 20% to 15%. More specifically, if it is 20% or less for pillars, 18% or less for sills and duck, and 15 to 10% for floorboards and interior materials, there will be almost no shrinkage or deformation of the wood, and bonding with nails, etc. It is said that the resistance is improved and the decay resistance is also improved.
This is the main purpose of wood drying. In recent years, adhesives are also frequently used in place of nails and bolts, but it is said that the moisture content of wood for achieving the maximum effect is 7-10%.
The strength of wood is generally expressed by Young's modulus (E), but it has been reported that the average is 122.13 for firewood and 90.95 for cedar.
However, strength and the like are sometimes insufficient only by drying, and a method of impregnating a curable resin into wood is adopted as one of the methods for further strengthening. This is what is called resin-impregnated reinforced wood.

There is already known a reinforced wood obtained by impregnating wood with oil, resin, wax or the like dissolved or emulsified in a solvent and then removing the solvent and drying. For example, JP 2003-73608 A discloses polyterpenes, hydrated resins, hydrated resin acids, esterified resins, esterified resin acids, dimerized resins, dimerized resin acids, oligomerized resins, oligomerized resin acids, and the like. Reported wood impregnated with a solvent-free melt of a chemically modified natural resin. However, the natural resin mentioned here is a special natural resin made of, for example, abietic acid derived from pine trees or roots, levovirumanic acid, or the like, or terpene, and does not necessarily have excellent impregnation properties. Therefore, since the wood referred to here is limited (not easy) to impregnate the melt into a large log-shaped wood, its application range is veneer, beams, panels, etc. with a thickness of several centimeters. The so-called plate material was limited.
Also known is a surface resin-injected wood (surface WPC (wood plastic combination)) in which the surface of the wood is impregnated with a resin. Resins used for WPC are unsaturated polyester resins and methyl methacrylate (MMA) monomers, which are solidified by heat polymerization or radical polymerization. However, many of these resins are hydrophobic and have poor affinity with hydrophilic wood, and it is extremely difficult to penetrate deep into wood, especially deep into temporary conduits and conduits. What you get is at most a few millimeters from the surface. Therefore, although WPC has been mass-produced industrially and has been effective, most of them are limited to plate-like timber with a thickness of several centimeters. Japanese Patent Laid-Open No. 2002-234002 reports a method for solving these problems by impregnating wood with an organic polyisocyanate and then curing it by bringing it into contact with water vapor.
JP 2003-73608 A JP 2002-234002 A

As mentioned above, the impregnating resin such as unsaturated polyester resin used for reinforced wood is not only hydrophobic but also has a large molecular weight, so it is extremely difficult to impregnate wood, especially in the fiber direction of wood. Yes, it could only be impregnated from the wood surface to a very slight depth. In addition, if the wood is not sufficiently dried and there is moisture in the temporary conduit or conduit, there are various problems such as the moisture in the wood preventing the resin from penetrating, and the resin penetrates deep into the wood. It was difficult to do.
Furthermore, since these unsaturated polyester resins are artificial resins, they are not only unfamiliar with wood, but also cannot fully exhibit the original characteristics of wood, such as moderate moisture absorption and release and the natural scent of natural wood. It was.
In addition, since many impregnating resins are hydrophobic and have a large molecular weight, a large amount of organic solvent is used for impregnation, so that the organic solvent remaining on the wood and unreacted chemical substances are gradually removed over time. It was released into the atmosphere and could have a negative impact on health. In addition, there were problems with health and the environment, such as the generation of toxic gases in the event of a fire.

  Therefore, the object of the present invention is not only to have the same strength as conventional reinforced wood, but also has water breathability, which is the original merit of wood, and has adverse effects on health and toxicity due to organic solvents and unreacted chemical substances. This is a provision of reinforced wood that does not generate toxic gas in the event of a fire, is extremely safe in terms of health and the environment, and maintains the merits of natural wood.

As a result of intensive studies to solve the above problems, the present inventors have used water-soluble cellulose polymer derivatives such as methylcellulose (MC), hydroxypropylmethylcellulose (HPMC), and hydroxyethylmethylcellulose (HEMC). The present invention has been completed by finding that these problems can be solved.
That is, the reinforced wood of the present invention is specifically as follows.
1. Reinforced wood obtained by impregnating a temporary wood conduit or a conduit with a water-soluble cellulose polymer derivative, followed by drying and solidification.
2. 2. The reinforced wood according to 1 above, wherein the water-soluble cellulose polymer derivative is methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), or a mixture thereof.
3. 3. The reinforced wood according to 1 or 2 above, wherein the wood is coniferous wood.

Since the water-soluble cellulose polymer derivative used as the impregnation resin in the present invention is a natural material or a material obtained by subjecting the natural material to some processing, various excellent effects as described below are exhibited.
・
The water-soluble cellulose polymer derivative is the same as the cellulose that forms wood and is more hydrophilic, so it can be impregnated not only on the wood surface but also on temporary conduits and conduits that were previously impossible. It is possible to impregnate to the deep part.
・
Although the physical strength of the water-soluble cellulose polymer derivative itself is inferior to that of the conventional unsaturated polyester resin, etc., it can be impregnated to the deep part of the wood. Compared with wood, the strength can be increased from 1.3 times to 1.5 times, and it is possible to obtain strength equal to or higher than that of conventional reinforced wood. In particular, when applied to inexpensive pine, etc., the strength equivalent to that of cocoons can be obtained, and the range of use of pine can be greatly expanded.
・
Thus, the reinforced wood of the present invention has the same strength as conventional reinforced wood reinforced with unsaturated polyester resin, etc., so that it is not only suitable for use as various structural materials such as columns and beams, but also warps, bends, Cracking, wood thinning (dry shrinkage) is prevented, brittleness is reduced, and mechanical strength is improved, so that the utility value as a plate material is significantly improved.
・
Water-soluble cellulosic polymer derivatives have high familiarity and binding properties with wood, and are water-soluble. Therefore, they are water-respirable, which is the original merit of wood (wood absorbs moisture from the outside at high humidity, and when dry, Conversely, the natural effects of natural wood can be exerted without damaging the water in the wood).
・
In addition, since the water-soluble cellulose polymer derivative is water-soluble, there is no adverse health effect or toxicity due to organic solvents or unreacted chemical substances.
・
Furthermore, in the case of a fire, no toxic gas is generated and it is extremely safe in terms of health and environment.

As described above, the present invention is a reinforcing material obtained by impregnating a temporary conduit or conduit of wood with a water-soluble cellulose polymer derivative such as methylcellulose (MC), hydroxypropylmethylcellulose (HPMC), or hydroxyethylmethylcellulose (HEMC) and drying and solidifying it. It is wood.

`` Wood '' for impregnating resin is not particularly limited, but means wood used for buildings and furniture such as houses, even conifer wood such as cedar and pine, Hardwood wood such as firewood, firewood, firewood and beech wood may be used. Specifically, cedar and pine are suitable, but the present invention is not limited to this, and can also be suitably applied to firewood, firewood, firewood, and beech wood. In the case of conifers such as cedar, a temporary conduit is impregnated, and in the case of hardwoods such as timber, the conduit is impregnated with a water-soluble cellulose polymer derivative. Here, the “temporary conduit” is a thin tube for sucking up water in a conifer, and the “conduit fence” is a thin tube for sucking up water in a hardwood.
The shape of the wood is not particularly limited as long as it is a dried wood, but is preferably a log, a square, a plate made by peeling off the bark, particularly preferably a log, a square, but a beam, a panel, a veneer, It may be a frame, laminated wood or the like.

The “water-soluble cellulose polymer derivative” is a polymer obtained by chemically modifying a part of so-called “natural cellulose” that forms a plant cell wall. These water-soluble cellulose polymer derivatives are also known as a shape retention agent for cement in water and a compounding agent for pharmaceutical preparations. It is stable without change over time, secures safety, and its aqueous solution has high surface activity, and is advantageous for impregnation into various substrates. Further, it can be easily dissolved in cold water or water / alcohol, and the film-forming ability is very excellent.
"Water-soluble cellulose polymer derivative"
For example, methyl cellulose (MC), hydroxypropyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), sodium carboxymethyl cellulose (CMC-Na), hydroxyethyl cellulose, etc. Cellulose derivatives; Lignocellulose (plant fibrin) materials obtained from agricultural waste such as rice straw, rice straw, and other residues generated in the lumbering process such as wood flour; Synthetic polymers such as polyvinylpyrrolidone and polyvinyl alcohol; pullulan, dextrin And starch derivatives such as
Among these, methylcellulose is a typical water-soluble cellulose and has excellent protective colloid properties, thermal gelation properties, lubrication properties, and water retention properties in addition to viscosity.
In addition, HPMC is frequently used as a cement mortar compounding agent and in cosmetics, medicines, and health foods by utilizing its characteristics. Since it is also used for food, its safety is extremely high.
Among them, methyl cellulose (MC), hydroxypropyl cellulose (HPC)
, Hydroxyethylmethylcellulose (HEMC) Hydroxypropylmethylcellulose (HPMC)
Sodium carboxymethyl cellulose (CMC-Na) is preferred.
Particularly preferred are methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), and hydroxyethyl methyl cellulose (HEMC). Specifically, from the “Metrozu (registered trademark)” series of Shin-Etsu Chemical Co., Ltd., “SM type” for MC, “SH type” for HPMC, and “SE type” for HEMC. Can be obtained from each grade.
These are nonionic water-soluble cellulose ethers obtained by chemically treating natural cellulose (natural pulp) and substituting some of the hydroxyl groups with methoxy groups, hydroxypropoxy groups, and hydroxyethoxy groups, respectively. is there.
Such water-soluble cellulose polymer derivatives may be used alone or in combination of two or more as required.

Moreover, you may add a flame retardant, a coloring agent, antioxidant, an antimicrobial agent, an insecticide, a repellent, an ultraviolet protective agent, etc. to these water-soluble cellulose polymer derivatives as needed. However, in order to achieve the original object of the present invention, it is preferable that these compounding agents have a minimum compounding amount.
Examples of the flame retardant include ammonium phosphate, zinc borate, organic phosphate ester, and organic halogen compound.
The colorant is not particularly limited, and various dyes, contents, paints, lacquers and the like can be used.
If necessary, antimicrobial agents such as bactericides and fungicides, insecticides, and repellents for mammals such as rodents may be blended. Moreover, when the use in the place exposed to sunlight is considered, you may mix | blend a ultraviolet-ray protective agent.

The manufacturing method of the reinforced wood of this invention is as follows.
The impregnation of the polymer derivative into wood is performed by a vacuum pressure impregnation method combining vacuum and pressure. When wood has moisture, it impedes the impregnation of the polymer derivative. Therefore, the wood is dried in advance to have a moisture content of 30% or less, preferably 20% or less. Moreover, since air has entered the dried wood, which prevents impregnation of the polymer derivative solution, it is necessary to perform a pre-vacuum process prior to the impregnation to remove the air in the wood.
As an apparatus for the vacuum pressure impregnation method, for example, “SBK type vacuum pressure impregnation apparatus” manufactured by Yasima Co., Ltd. can be used.
The impregnation amount of the polymer derivative is 250 L / m ³ in the diluent. The dilution rate may be appropriately diluted according to the type of polymer derivative.
The pressurizing method for impregnation may be a “liquid pressurizing method” or an “air pressurizing method”.
The “liquid pressurization method” includes the following steps.
1. 5 to 20 woods dried to a moisture content of 15% to 20% (water content = (wood weight−completely dry weight) / completely dry weight) are placed on a cart and cans (vacuum / pressurized) Into the tank).
2. Close the door and seal the inside of the can.
3. “Pre-vacuum”: The inside of the can is evacuated to remove the air in the wood so that the resin is easily impregnated into the wood.
4). The impregnating liquid is poured into the pressurized tank by a drop from the impregnating liquid storage tank at the top of the “liquid container” can.
5. “Pressurization”: When the tank is filled with the impregnating liquid, pressurization is performed with a pressure pump (the set time is until the injection amount is reached). The liquid pressurization is usually 10 kg / cm ² and the injection amount is 250 kg / m ³ .
6). Fluid pressure leak: Return fluid pressure to atmospheric pressure.
7). Liquid return; The impregnating liquid is pumped back to the head tank.
8). Post-vacuum: A vacuum is applied to remove excess impregnating liquid after impregnation or prevent dripping from the wood.
9. Leak; return to atmospheric pressure10. Recovery of residual liquid; recover excess surplus impregnating liquid that was discharged in a vacuum afterwards.
"Air pressurization method"
In the pressurizing step 5 of the “liquid pressurizing method”, pressurization is performed using an air compressor instead of the pressurizing pump.
After the impregnation of the polymer derivative into the wood is completed as described above, it is dried by an appropriate method.
The drying method of the impregnated wood may be either a wet method or a dry method.
In the wet method, after impregnating dry wood, the product is taken out in a wet state and then dried.
The dry method is a method of impregnating dry wood and taking out the product in a dry state.
Moreover, drying may be naturally dried or forcedly dried.

After 10 pine materials (logs with bark peeled) dried to a moisture content of 15% to 20% were placed on a carriage, carried into a can (pressurized tank), closed and sealed, The inside of the can container is evacuated to a vacuum. Next, the impregnating liquid is poured and filled into a can container (pressurized tank) by a drop from an impregnating liquid storage tank filled with a natural cellulose resin aqueous solution (methyl cellulose). The impregnation with the aqueous resin solution is performed under a reduced pressure. That is, with pine wood immersed in an aqueous resin solution, the pressure was reduced at 0.3-0.8 atm for 15 minutes, then 0.8-0.95 atm for 30 minutes, and then 3.0-7.0 atm. And pressurizing for 45 minutes. After confirming that the impregnation injection amount is about 250 kg / m ³ , the remaining resin solution is returned to the impregnation liquid storage tank, and forcedly dried while the carriage is placed in the can container (pressurized tank).
When pine wood was impregnated experimentally with methylcellulose, the resulting pinewood was sufficiently impregnated with methylcellulose up to the temporary conduit, and its Young's modulus was increased 1.4 times, and the color tone started. The nature of natural wood was maintained.

  Since the reinforced wood of the present invention is impregnated with a water-soluble cellulose polymer derivative to the deep part of the wood, it has not only the same strength as a conventional reinforced wood reinforced with unsaturated polyester resin, but also the original wood. It has the advantage of water respiration, has no adverse effects or toxicity to health due to organic solvents or unreacted chemicals, does not generate toxic gases in the event of a fire, and is extremely safe in terms of health and the environment. The merit of natural wood is maintained as it is. Therefore, it is useful as a building material such as a pillar, a sill, a duck, a floorboard, and an interior material, or as a wooden furniture material. In particular, when it is applied to inexpensive and easily available pine, etc., the strength equivalent to that of cocoons can be obtained, so the range of use can be greatly expanded.

Claims (3)

  Reinforced wood obtained by impregnating a temporary wood conduit or a conduit with a water-soluble cellulose polymer derivative, followed by drying and solidification. The reinforced wood according to claim 1, wherein the water-soluble cellulose polymer derivative is methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), or a mixture thereof.   The reinforced wood according to claim 1 or 2, wherein the wood is coniferous wood.