JPS62292404A - Conservative treated wood - 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] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to preserved wood used as a material for buildings, etc., specifically, preservatives, insect repellents, and termiticides. , relates to the improvement of preserved wood treated with various wood preservatives such as fire retardants to extend the useful life of the wood.

[Conventional technology] In general, wood is cheaper and easier to process than other structural materials, has a high specific strength, is rich in toughness, is soft to the touch, and has an elegant appearance, so it is used for buildings such as houses. It is widely used in various industrial fields including.

However, since it is an organic material, it is susceptible to biological deterioration such as decay, insect damage, and ant damage, and because it expands and contracts when it absorbs moisture and dries, and its strength is directional, it is susceptible to warping, warping, cracking, etc. It also has various drawbacks such as being easily flammable.

Especially for wood used as structural material for housing,
In addition to maintaining biological deterioration resistance for at least 10 years, workers who handle wood that has been treated with various preservatives may become contaminated with the preservatives and pose a health risk. It is required that the treated wood does not cause any deformation such as warping or warping, or dimensional changes until it is finally used.

Traditionally, wood preservation technology has mainly focused on preventing biological deterioration, such as preservatives, insect repellents, and termite repellents, and the preservatives used for this purpose are chromium/copper/arsenic compound wood preservatives (CCA) and boronic compounds. Water-soluble drugs such as, oil-based drugs such as creosote oil, chlordane, tributyltin oxide (TBT)
Various fungicides, insecticides, and termiticides such as organic solvent-soluble (oil-soluble) drugs such as -0) are used. Common methods for adhering and absorbing these preservatives to wood include pressurized injection, coating, and dipping.

[Problem that the invention seeks to solve]

However, various problems have been pointed out in wood preservation treatment techniques using such preservatives.

In other words, for example (if we look at 11CCA, preservatives,
It has excellent insect repellent and termite repellent properties, and is a typical preservative for wood that is treated exclusively by pressure injection. Although it is toxic itself, it is reduced to a substantially harmless form when it comes into contact with wood. Change. However, since this reduction reaction progresses gradually, it usually takes 2 to 3 weeks, although it varies depending on the temperature conditions. During this period, it is necessary to store the CCA in the processing plant from the viewpoint of protecting the natural environment and the health and hygiene of humans and animals, and this period is usually called the curing period of CCA. During this curing period, the treated wood is stored in the factory, which is considered to be the biggest drawback of CCA conservation treatment. Therefore, as a solution, CCA
Attempts have been made to shorten the curing period by steaming or drying wood that has been pressure-injected with wood, but such treatment methods have the problem of significantly deforming the treated wood and significantly reducing yield. be. Furthermore, since pressurized injection of CCA into wood simultaneously results in a large amount of moisture being retained in the wood, the treated wood may become deformed during subsequent drying, resulting in an even more significant drop in yield. To prevent cracks at the end of the wood that occur due to drying and shrinkage, there is a method of applying resin paint to the end of the wood in order to delay the evaporation of water, but the density of the paint on wet wood and the The effect is not sufficient because the coating film has low followability to deformation. There is also a method of applying polyethylene glycol (PEG) to the end of the wood as a dimensional stabilizer, but it has not been put into practical use due to difficulties in terms of effectiveness, workability, cost, etc.

(2) Oil-based creosote oil is a chemical that has been commonly used as a preservative and insect repellent for a long time, and is applied to wood by pressure injection or coating, but it has a strong odor and is irritating to the skin. In recent years, there have been concerns about carcinogenicity. Furthermore, since it is difficult to dry, it has various drawbacks such as contaminating the skin of workers' clothes and hands during the distribution and use process of treated wood, and causing skin rashes.

Therefore, attempts have been made to overlay treated surfaces with resin paints, etc., but these have not been sufficiently effective, and the reality is that the use of wood treated with creosote oil is decreasing year by year.

(3) Furthermore, most oil-soluble organic chemicals such as TBT-0 are applied to wood by surface treatment methods such as dipping, coating, and spraying after being dissolved in an organic solvent. Since many of these are relatively easily volatile, the active ingredients that have lost their carriers due to the volatilization of the solvent after wood treatment cannot penetrate into the interior of the wood, and at most
It often remains in the surface layer within μ and does not have sufficient effect.

Furthermore, since many organic chemicals themselves are highly volatile, they are lost from the treated wood in a relatively short period of 3 tJ1, resulting in a lack of long-lasting effects. Therefore, as a preventive measure, attempts have been made to treat wood by dissolving chemicals in a non-volatile solvent, but since it is non-volatile, it has the same drawbacks as the creosote oil mentioned above and is not practical. There is a problem.

The present invention was made by focusing on the above-mentioned various problems of so-called preservation-treated wood treated with preservatives. (1) The preservation effect of preservation-treated wood can be sustained for a longer period of time; (2) To prevent workers from being contaminated by preservatives adhering to the wood, and (3) to provide preserved wood that does not warp, warp, or crack during the distribution and use processes. With the goal.

[Means for solving problems]

That is, the present invention is a preservative-treated wood obtained by covering wood treated with a preservative with a moisture-releasing film.

The method for producing preserved wood of the present invention will be explained below.

First, the wood is sawn into a square lumber or other predetermined shape from a log, and the moisture content is maintained at a moisture content (approximately 25%, although it varies depending on the tree species) without drying or causing deviation in the shape and dimensions. After drying (as above), various wood preservatives such as preservatives, insect repellents, termiticides, etc.
One or more types of fire retardants, dimensional stabilizers, etc. are appropriately selected depending on the purpose of use, and the wood is treated by a known method to obtain chemically treated wood. Next, if necessary, the chemically treated wood with shallow molding is drained and then covered with a film with low moisture permeability.

As the film having low moisture permeability, plastic films having low water permeability and low moisture permeability and thermoplasticity, such as films of vinyl chloride, vinylidene chloride, polyethylene, polypropylene, etc., can be suitably used. In addition, wood can be covered with a film by any known means as appropriate, but it is possible to utilize the heat shrinkability of the film to heat the entire film from the outer periphery of the film wrapped around the wood to shrink the film while wrapping it on the surface of the wood. The simplest method is so-called shrink packaging. According to this method, the plastic film described above can be used as it is, and by simply passing the film wrapped around the wood through a hot blast oven, it is possible to cover the outer peripheral surface of the wood in close contact with the film. in this case,
It is not necessary to coat the chemically treated wood with a film over the entire outer circumferential surface of the wood, and covering the end surfaces and the like may be omitted. Further, although it is preferable to coat the chemically treated wood pieces individually, it is also possible to bundle and coat several pieces of wood.

[Effect]

Since the preserved wood of the present invention is constructed as described above,
■Deformation, cracking, etc. caused by drying shrinkage of wood treated with preservatives is prevented. ■Encourage the infiltration of treatment chemicals into the interior of the wood during wood preservation, improving effectiveness and sustainability. ■It has remarkable effects such as preventing contamination and health problems for workers during the distribution and use process of chemically treated wood.

Conventionally, covering many products, not just wood, with protective films has been widely used to prevent staining and quality changes during the distribution process, but as mentioned above, there are chemicals that have completely different effects. Film coating on treated wood is not yet known.

〔Example〕

The present invention will be described in further detail below with reference to Examples and Comparative Examples.

Example 1 15 base timbers measuring 1Q, 5cm x IQ, 5cm x 4m were sawn from logs with an average moisture content of 90%.
It was naturally dried to a moisture content of about 60%, and a 2% aqueous solution of CCA was injected under pressure, and the liquid was drained for 24 hours. This chemically treated wood was immediately individually shrink-wrapped using a 40 μm thick polyethylene film to obtain the preservation-treated wood of the present invention.

Comparative Example 1 Thirteen pieces of wood similar to those in Example 1 were sawn and dried in the same manner as CC.
After injecting a 2% A aqueous solution under pressure, the wood was left to cure naturally for 3 weeks to obtain preserved wood.

The preserved wood obtained in Example 1 and Comparative Example 1 was subjected to a normal distribution process, and after about one month, was used as a base for construction.

Note that the treated wood of Example 1 was used at a construction site with the coating film removed.

Both the treated wood of Example 1 and Comparative Example 1 showed no environmental pollution during the distribution process, and in both cases, the fixation reaction of CCA to the wood had been completed and there was no contamination to workers handling the wood. However, while the treated wood in Example maintained its straight state when it was sawn, in Comparative Example 1, one bent and three twisted (one of them overlapped with the bend). It was not suitable for use.

Example 2 10.5 Ca1l x 10.5 ctn x in the United States
Apply creosote oil No. 1 specified in JISK 2470 twice to a coating amount of 300 g/rrr to 10 hemlock base timbers (average moisture content about 60%) that were sawn to 4 m in length, and then immediately The wood was individually shrink-wrapped using a 40 μm thick polypropylene film to obtain the preserved wood of the present invention.

Comparative Example 2 Eleven pieces of wood similar to those in Example 2 were coated with creosote oil twice in the same manner to obtain preservation-treated wood.

The preserved wood of Example 2 and Comparative Example 2 was used as a base for construction after about 10 months through a normal distribution process. In addition,
The product of Example 2 was used as it was without removing the covering film.

When used for construction, a part of the creosote oil treated area was scraped off and extracted with xylene, and then the creosote oil was quantitatively analyzed using JI SK2425, and there was no difference between the two, but a similar test was conducted one year later. As a result, there was no change in the case of Example 2 from the beginning, but in the case of Comparative Example 2, the distillation amount up to 235℃ was 70%, and the distillation rate was 235-315℃.
The distillation amount at °C was reduced to 90%.

It was found that the preserved wood of the present invention particularly contributes to retaining the low-temperature fraction of creosote oil compared to conventional products, and has a long-lasting effect.

In addition, when a soaking degree test was conducted in accordance with JISA9104, the soaking length of the preserved wood of Example 2 at the time of construction was 4 dragons, and that of Comparative Example 2 was 2 cranes, whereas the length of soaking after 1 year was In the later tests, the thickness of Example 2 was 8 mm, and the thickness of Comparative Example 2 was 3 mm.

From these results, it was found that the preserved wood of the present invention, whose surface was treated with the creosote oil of the present invention, could be given a deeper immersion length over time.

Furthermore, while the preserved wood of the present invention did not contaminate workers or adversely affect their health during the distribution and use process, the left and right lower arms of the workers who handled the preserved wood of Comparative Example 2 Moderate rash occurred on the body and neck. In addition, the preservation treated wood of Comparative Example 2 had 2 out of 11 pieces when used.
While the books were twisted and unsuitable for use, all of the books of the present invention had no problems such as deformation.

Example 3 Spruce Pine Fir (SPF) mixture sawn to 9 cm x 9 cm x 4 m in the United States (average moisture content approximately 70%)
) 28 The amount of TBT-01% kerosene solution applied to wood is 20
0 g/g and immediately individually shrink-wrapped using a 20μ thick vinyl chloride film to obtain the preserved wood of the present invention.

Comparative Example 3 TBT-01 was applied to 28 pieces of wood similar to Example 3 in the same manner.
% kerosene solution was applied to obtain preserved wood.

The preserved wood of Example 3 and Comparative Example 3 was subjected to a normal distribution process, and about one month later, it was used as a lumber for construction. In addition, the product of Example 3 was used as it was without removing the covering film.

When used for construction, the surface of the wood was scraped to a depth of 9 cal, extracted with ether, and analyzed by gas chromatography to determine TBT-0.
Quantitative analysis revealed that 100% remained in the preserved wood of Example 3 compared to immediately after treatment, whereas in Comparative Example 3
This had decreased to 82% of its original value. Furthermore, when a similar analysis was conducted one year later, more than 99% of TBT-0 remained in the sample of Example 3, whereas the remaining amount of TBT-0 in Comparative Example 3 decreased to 42%. It has been found that the preserved wood of the present invention maintains its effect over a long period of time.

In addition, when a dithizone reagent was used to test the degree of immersion after one year, the immersion length of Example 3 was 1.3 fins, whereas the immersion length of Comparative Example 3 was Q, 4 mm. It can be seen that the preservative-treated wood of the present invention has a drug-infiltrated layer three times or more larger than that of conventionally-treated wood, and maintains a high preservative effect.

In addition, during the distribution and use process of these treated wood, the preserved wood of the present invention did not contaminate workers or adversely affect their health, whereas the workers who handled the treated wood of Comparative Example 3 did not. A moderate rash occurred on the left and right lower buttocks.

Furthermore, when using the preservative treated wood of Comparative Example 3, 6 out of 28 pieces were twisted and 2 pieces were bent, making them unsuitable for use, whereas all of the wood pieces of the present invention had no problems such as deformation. I didn't.

In addition, wood that has been surface treated with chlordane, an anti-termite insect repellent, pressurized injection treatment with borate, an insect repellent, and pressure injection treatment with a fire retardant consisting of a mixture of phosphorus compounds and boronic compounds. However, for all volatile chemicals, we suppressed their volatilization and increased the infiltration length of the chemicals into the wood, resulting in sustained effects. Moreover, it did not contaminate workers and did not cause any distortions such as bending or twisting during use.

Claims (1)

[Claims] Preservation-treated wood characterized by covering wood treated with a preservative with a moisture-resistant film.