JP2000071216A - Wood material and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wood material which is manufactured by using a thinned- out log, a small dia. tree or a low density wood as a wood material hardly utilized heretofore and can be applied to structural uses as well as a method for manufacturing this wood material. SOLUTION: The method for manufacturing this wood material is to manufacture a wood material of a plurality of pieces of wood strand laminated and mutually bonded together in one piece. That is, the wood material of a strand shape with 5-100 mm width, 0.1-5 mm thickness and 150-200 mm length on the average and wood are cut, shaved or split in the strand form 5-100 mm wide, 0.1-5 mm thick and 150-200 mm long on the average. Further this wood strand has an applied adhesive and the pieces of the strand are laminated over each other into a matlike form, which is, in turn, pressurized and heated so that the adhesive is set and the entirety is integrated as one monolithic body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood-based material in which wood strands are bonded and integrated.

[0002]

2. Description of the Related Art In recent years, as a building material, raw wood has been subdivided into elements of a certain size, such as particle board and medium density fiberboard (MDF), and the elements have been integrated with an adhesive or the like to form a wood-based material. The use of reconstituted materials (hereinafter sometimes abbreviated as reconstituted EW) is increasing.

[0003] In these, by dividing wood as a raw material into elements, it is possible to disperse or remove performance defects such as knots inherent in wood, and to obtain uniform performance. It can be a material. In addition, since the raw wood is subdivided, it can be made from wood with many nodes, which cannot be used as it is, or thinned wood or small-diameter wood, which is useful from the viewpoint of effective use of resources.

[0004] However, those subdivided into very small elements, such as particle board and MDF, have low strength performance and cannot be used as structural members. On the other hand, it has been proposed to obtain a wooden board having sufficient strength and rigidity by bonding a large number of thin pieces of wood obtained by slicing wood using a wafer riser, a flaker, or the like to form a multilayer structure ( See JP-A-7-76004).

[0005]

However, it has been found that the wood board described in the above publication is not always satisfactory in terms of strength, and is not a product that can be used for all structural applications. The present invention has been completed in view of the above points, and is a wood material that can be used for thinning materials, small-diameter trees, and low-density materials that have been rarely used, and that can be used for structural applications. The purpose is to provide.

[0006]

The wood material according to claim 1 is a wood material in which a plurality of wood strands are integrated and bonded and integrated with each other, wherein the strand shape is 5-100 mm in width, 0.1-5mm thickness and average length
It is characterized by being 150-200mm.

According to a second aspect of the present invention, the woody material has a higher density than the raw wood and has a compression recovery ratio of 5% or less. The wood material according to claim 3 is the wood material according to claim 1 or 2 which is compressed by 10% or more with respect to the raw wood.

According to a fourth aspect of the present invention, there is provided a method for producing a woody material, comprising cutting, cutting or splitting wood to a width of 5-100 mm and a thickness of 5-100 mm.
The strand shape is 0.1-5mm and the average length is 150-200mm.Adhesive is applied to these wood strands, a plurality of them are integrated into a mat, and the mat is pressurized and heated. The method according to claim 1, wherein the adhesive is cured to integrate the whole.

According to a fifth aspect of the present invention, in the method for producing woody material, the adhesive is hardened in a state where the strands are compressed at the time of heating, the whole is integrated, and the density is made higher than that of the raw wood. The method according to claim 4, wherein the compression restoring stress is reduced by performing the treatment to reduce the compression restoring rate to 5% or less.

[0010] According to a sixth aspect of the present invention, there is provided a method for producing a woody material, wherein the raw wood is compressed by 10% or more. The method for producing a woody material according to claim 7 includes a step of compressing the strand to make it denser than the raw wood, a step of heating and curing the adhesive to integrate the whole, and a process using high-temperature and high-pressure steam. The method for producing a woody material according to claim 6, wherein the step of reducing the compressive restoring stress and reducing the compressive restoring rate to 5% or less is performed during one press clamping cycle.

Hereinafter, the present invention will be described in more detail. In the present invention, the strands are 5-100 mm in width and 0.1-5 m in thickness.
m and an average length of 150-200 mm are used.
Out of this range, narrow strands are particularly difficult to form with wafer risers and flakers, etc. Conversely, if the width is wide, the seams of the strands will be widened accordingly, and the effect of dispersing the defects with the strand shape will be weakened. It is because.

A strand having a thickness smaller than the above range is liable to cause a defect such as breakage in a manufacturing process. Conversely, if the thickness is large, a large gap is formed at a joint portion of the strand. As a result, the effect of dispersing the defects is reduced. If the length is shorter than this range, the required strength performance may not be obtained.On the other hand, long strands will increase the size of the wafer riser, flaker and other blades, and accordingly, laminating equipment and adhesive coating equipment This is because such a device becomes large and inefficient.

In the present invention, the compression ratio is defined as follows. Compression ratio (%) = [(density of product−density of raw wood) / density of product] × 100 Further, the compression recovery ratio is defined as follows. Compression recovery rate (%) = [(dimension after drying-dimension before immersion treatment) / dimension before immersion treatment] x 100 where, dimension: dimension of evaluation sample in dimension in compression molding direction of product Treatment: immersion treatment in water at a water temperature of 40 ° C. or less for 24 hours. Drying: Drying after immersion treatment to the water content before immersion treatment.

Known methods such as cutting, cutting, splitting and the like can be applied as a strand forming method. For example, a method of cutting by a wafer riser, a flaker, or the like is generally used. Alternatively, a veneer veneer may be prepared from a veneer log using a veneer racer, and a strand may be formed from the veneer by cutting, splitting, or the like. The strand may be formed by directly splitting from a lumber backboard, a small diameter tree, a veneer core, or the like.

As raw wood for forming the above-mentioned strand, for example, cypress, sawara, hiba, kaya, cedar,
Toga, maki, various pine, paulownia, maple, birch, spine, beech, oak, fir,
Domestic lumber, oak, kusu, zelkova, rice cypress, rice hiba, rice cedar,
North American lumber such as rice fir, spruce, rice pine, hard pine, soft pine, Yonega, redwood, aspen, etc., southern lumber such as Agati, Terminaria, Rawang, Merunch, Sengong Laut, Junkon, Chamelere, Karampayan, Amberoi, Melina, Teak etc. , Other materials such as balsa, cedro, mahogany, lignum vita, atapine, acacia mangum, douglasfa, mediterranean pine, etc. can be used. In addition, the form is not limited to ordinary logs and lumber products, but can also be used for lumber backboards, small-diameter trees, thinning materials, building scraps, construction waste materials, and the like.

An object of the present invention is to provide a wood material which can be used for small diameter trees, thinned wood, and low density wood and can be used for structural purposes. In the case of high-density tree species, such as rice pine, when compressing as high as 10% or more as described in claim 6 of the present invention, higher strength can be expected and knots and the like can be expected. Since defects are eliminated, the effect of uniform stabilization of performance can be obtained.

Further, in the case of lumber products made only from raw wood, low-density and low-physical materials which cannot be used for structural purposes, for example, aspen,
Sengon Laut (see Example 3), Chamelere (Example 4)
Even when the material is highly compressed as described in claim 6 of the present invention, it can be a material that can be suitably used for structural applications and is very useful. .

Since the strength performance of a product has a high correlation with the density of the product, the density of the product can be selected according to the strength performance required by a site where the product is used. Generally, 0.3 g / cm3 to 0.9 g / cm3 (dry) is suitable, and among them, 0.4 g / cm3 to 0.8 g / cm3 (dry) is more preferable.

The method of the present invention is very useful in that the required product density can be freely set unlike ordinary lumber products. In the present invention, a known method can be applied as the heat and pressure molding method. For example, batch methods such as hot plate press and steam injection press,
Any of a continuous press method using heating such as microwave, high-frequency dielectric, and steam injection, and a continuous batch method using a hot plate or steam injection can be applied. Among these methods, the method using continuous pressing is a preferable method because the length of the molded product can be arbitrarily set as required, so that the material efficiency is high.

Further, in the present invention, various methods can be adopted as a method of performing high-temperature and high-pressure steam treatment. For example, a method in which high-temperature and high-pressure steam is introduced into a molded product while maintaining the shape of the molded product in a mold placed in a closed container, or a molded product in a container is heated by a hot plate, microwave, or high-frequency dielectric. Heating by such a method, vaporizing the moisture in the molded article, or treating the mold, sealing around the mold, forming a closed space with the mold itself, placing the molded article in it, A method of performing steam treatment by the above-described method of introducing high-temperature and high-pressure steam or vaporizing water by a hot plate, microwave, high-frequency dielectric, or the like can be adopted.

In the present invention, a step of compressing a strand to make it denser than raw wood during a single mold clamping cycle of a press, a step of heating and curing an adhesive to integrate the whole, In order to reduce the compressive restoring stress by treating with high-temperature and high-pressure steam and perform the entire process of reducing the compressive restoring ratio to 5% or less, the following method is employed as a molding method.

Pressing is performed by holding a high-temperature and high-pressure steam for a certain period of time, for example, by placing a mold in a closed container or by sealing the periphery of the mold and creating a closed space by the mold itself. It must have a structure that can be used.

As a method of treating with high-temperature and high-pressure steam,
For example, there is a method in which a steam supply hole is provided in a closed container or a compression plate or a side plate of a closed mold and steam is supplied to the material from the outside through the supply hole, or a method in which the material is vaporized by heating the material. . As a heating method in the method of evaporating the contained water, there are methods such as a hot plate, microwave, and high frequency dielectric.

In the present invention, the adhesive may be cured simultaneously by heating or introducing steam for performing high-temperature and high-pressure steam treatment, or a material may be previously cured by a hot plate in order to cure the adhesive. Alternatively, heating may be performed by a method such as steam injection, microwave, or high-frequency dielectric, and then high-temperature and high-pressure steam treatment may be performed by further heating or introducing steam.

However, considering the shortening of the press cycle time and the deterioration of the material or the adhesive due to exposure to the heat in a high temperature state, it is preferable that the curing of the adhesive and the high-temperature and high-pressure steam treatment are performed in parallel. From this viewpoint, when the method of supplying steam to the material from the steam supply hole is adopted, if high-temperature and high-pressure steam is directly introduced into the strand from the compression surface of the mold, the adhesive can be quickly cured by the heat of the steam. In addition, the compression restoring stress can be alleviated simultaneously and quickly, so that the entire process can be completed within a short time, which is a preferable method.

As the adhesive in the present invention, a known adhesive such as used in the production of plywood can be applied. For example, a phenol-based, resorcinol-based, urea-based, melamine, maleic acid-based, isocyanate-based adhesive, a co-condensate thereof, or a mixture thereof is used. Among them, an isocyanate-based adhesive has a property that a curing reaction is caused by moisture and the reaction speed is very fast.

In the present invention, as described above, in order to perform high-temperature and high-pressure steam processing, a method of introducing steam or vaporizing moisture of a material is used.
When an isocyanate-based adhesive is used, the curing reaction is caused by the steam, so that the curing of the adhesive and the steam treatment can be performed simultaneously in parallel, which is very effective, and the entire process can be performed in a short time. Most preferred because it can be terminated. When compressive restoring stress is reduced by high-temperature and high-pressure steam processing, the required processing time is determined by the processing temperature, as shown in FIG. 1 (graph 1). For example, when the treatment is performed at 200 ° C., the treatment time may be about 4 minutes (holding time in the high-temperature and high-pressure state). When the treatment is performed at 180 ° C., the high-temperature and high-pressure state is preferably maintained for 10 minutes or more.

(Operation) In the present invention, by limiting the shape of the strand, a wood-based material that can be used for all structural applications can be provided. Wood naturally has the property of swelling when absorbing water and contracting when dried. Usually, lumbering is performed in a state close to freshly cut raw trees, and dried to produce lumber products. In such a case, irregularities such as warpage and bending due to drying shrinkage occur. In the case of conventional construction of houses, it is possible to make corrections at the construction site,
Such a disorder was not a big problem.

However, in the case of a method using precut wood, a house using a frame wall method, and an industrialized house (precut), etc., which are increasing in recent years, the material requires high dimensional accuracy, so that the drying shrinkage is large. It becomes a problem. Since the reconstituted EW generally uses a dried material as a raw material, such drying shrinkage does not occur and is useful. However, since high-density reconstructed EW is made by compression-molding raw wood, if water is absorbed by dew condensation in the wall or rainwater at the construction site, not only the original water absorption expansion of the wood but also the compression recovery Swelling, which in the wet state can lead to significant dimensional deviations.

The original water absorption and expansion of wood is about 3 to 5%, but it is reported that the compression / restoration expansion rate is about 10% even if it is small, and 20% or more if it is large. In the case of ordinary house construction, the expansion of about 5% is about the same as the original water absorption expansion of wood, so it is a size that can be sufficiently eliminated by the construction method, but if it is larger than that, the construction method needs to be changed And

Further, since the compression-recovery expansion is irreversible unlike the original water-absorbing expansion-drying shrinkage of wood, even if the water-absorbed product is dried, the irregularity of the dimensions remains. If such a disorder is large, the product cannot be used,
In the case of an industrialized house, it may be necessary to change the production line to correct the disorder. In addition, in a house after construction, if it exceeds the level that can be resolved by the construction method, steps will occur on the floor or wall, nails, bolts, brackets, etc. for fixing will be inset, or reverse. It will be lost.

In the case of the product according to the method of the present invention, since the compression / restoration ratio is set to a very small value of 5% or less, the product cannot be used as a defective product and the line is changed to correct the error. There is no need. Further, even in a house after construction, there is no step, no sinking or dropout of the bracket.

In a method for measuring the coefficient of water absorption swelling according to a normal standard or the like, expansion is performed by spraying or dipping, and the size is measured in a wet state. In such a method, there is no distinction between the natural water-absorbing swelling-drying shrinkage and the compression-restoring expansion of wood. Here, as described above, in the present invention, the ratio between the dimension before immersion and the dimension after drying is taken, and the ratio is defined as the compression recovery ratio, which is used as a reference. It is possible to clearly classify the compression-recovery expansion.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. (Example 1) From a log of Yonematsu (total dry density 0.5g / cm3), it was cut with a knife ring breaker to a width of 10mm and a thickness of 2mm.
A strand having an average length of 180 mm was created. The strand is dried to a moisture content of 7% and then 5 parts by weight of adhesive (Polymeric MDI), based on the total dry weight of the strand
Was spray applied.

7.5 kg of this strand is formed in a hot plate press at 120 ° C. for 10 minutes, and the width is 240 mm, the thickness is 45 mm, and the length is 100 mm.
It was a 0 mm plate. The density of the formed product is 0.6 g /
cm3, bending stress 850kgf / cm2, flexural modulus 120,000kgf
/ cm2 (measured at a water content of 10%).

Example 2 A plate prepared in the same manner as in Example 1 was subjected to a steam treatment in an autoclave at 180 ° C. for 10 minutes to relax the compression restoring stress. The density of the formed product is 0.6g / cm3 (compression rate 16.7%) in terms of total dryness, and the bending stress is 800k.
gf / cm2 and flexural modulus were 110,000 kgf / cm2 (measured at a water content of 10%). Also, after immersing in 20 ° C water for 24 hours, drying in a 60 ° C oven for 3 hours and measuring the compression recovery ratio, it was 2%
Met.

Example 3 Sengon Laut (Total Dry Density 0.
A strand was prepared from the raw wood (25 g / cm3) in the same manner as in Example 1, dried to a water content of 8%, and then coated with an adhesive in the same manner as in Example 1. The strand was sprayed with steam at 180 ° C. by a continuous steam spray press, held for 10 minutes, and then cut to form the same plate as in Example 1. This plate was steamed in an autoclave at 180 ° C. for 10 minutes to reduce the compression restoring stress.

The density of the resulting molded article is 0.55 g / cm on a dry basis.
At 3 (compression rate 54.5%), the bending stress was 480 kgf / cm2, and the flexural modulus was 79,000 kgf / cm2 (measured at a water content of 10%). After immersion in 20 ° C. water for 24 hours, drying in a 60 ° C. oven for 3 hours and measurement of the compression recovery rate revealed 4%.

(Example 4) Chamelere (total dry density 0.32 g / cm)
A strand was prepared from the raw wood of 3) in the same manner as in Example 1, dried to a water content of 8%, and then coated with an adhesive in the same manner as in Example 1. This strand (6.7 kg) was sprayed with steam at 180 ° C. in a closed-type steam spray press, held for 10 minutes, and subjected to compression stress relaxation treatment at the same time as molding. The density of the resulting molded product is 0.55 g / cm on a dry basis.
At 3 (compression rate 41.8%), the bending stress was 520 kgf / cm2, and the flexural modulus was 82000 kgf / cm2 (measured at a water content of 10%). After immersion in water at 20 ° C. for 24 hours, drying in a 60 ° C. oven for 3 hours and measurement of the compression recovery rate revealed 3%.

Comparative Example 1 A molded plate was prepared in the same manner as in Example 1 except that the average strand length was 90 mm. The density of the resulting molded article is 0.6 g / cm3 on a dry basis, the bending stress is 200 kgf / cm2, and the flexural modulus is 45000 kgf / cm2 (water content
10%).

(Comparative Example 2) A molded plate was prepared in the same manner as in Example 2 except that the compressive stress relaxation treatment was not performed and the average strand length was 90 mm. The density of the resulting molded article is 0.6 g / cm3 (compression rate 16.7%) in terms of total dryness, the bending stress is 180 kgf / cm2, and the flexural modulus is 42000 kgf / cm2 (water content 10
%). After immersion in water at 20 ° C for 24 hours,
After drying in an oven oven at 3 ° C. for 3 hours, the compression recovery was measured and found to be 10%.

(Comparative Example 3) A molded plate was prepared in the same manner as in Example 3 except that the compression stress relaxation treatment was not performed and the average length of the strand was 90 mm. The density of the resulting molded article is 0.55 g / cm3 (compression rate 54.5%) in terms of total dryness, the bending stress is 150 kgf / cm2, and the flexural modulus is 42000 kgf / cm2 (water content
10%). After immersion in 20 ° C water for 24 hours,
After drying for 33 hours in a 60 ° C. oven, the compression recovery rate was measured and found to be 25%.

(Comparative Example 4) A molded plate was prepared in the same manner as in Example 4 except that the compression stress relaxation treatment was not performed and the average length of the strand was 90 mm. The density of the resulting molded article is 0.55 g / cm3 (compressibility: 41.8%) on a dry basis, the bending stress is 140 kgf / cm2, and the flexural modulus is 40,000 kgf / cm2 (water content
10%). After immersion in 20 ° C water for 24 hours,
After drying in a 60 ° C. oven for 3 hours, the compression recovery ratio was measured and found to be 18%. Table 1 shows the physical properties of the molded plates obtained in the above Examples and Comparative Examples, such as the compressibility and the bending stress.

[0044]

[Table 1]

[0045]

According to the first aspect of the present invention, the wood material is a wood material in which a plurality of wood strands are integrated and bonded and integrated with each other, and the strand shape has a width of 5 to 100 mm.
, Thickness is 0.1-5mm, and average length is 150-200mm
Therefore, it is possible to use small-diameter wood, thinned wood, and low-density wood without using long and long lumber products as materials, and the strand shape is within an appropriate range. is there.

The woody material according to claim 2 has a higher density than the raw wood and has a compression recovery ratio of 5% or less. It is reduced to such an extent that it is not high, and is suitable as a woody material in Japan with high temperature and humidity. Since the woody material according to claim 3 is a woody material according to claim 1 or 2 which is compressed by 10% or more with respect to the raw wood, sufficient strength can be secured.

According to a fourth aspect of the present invention, there is provided a method for producing a woody material, comprising cutting, cutting or splitting wood to a width of 5-100 mm and a thickness of 5 mm.
The strand shape is 0.1-5mm and the average length is 150-200mm.Adhesive is applied to these wood strands, a plurality of them are integrated into a mat, and the mat is pressurized and heated. The method for manufacturing a woody material according to claim 1, wherein the adhesive is cured to integrate the entirety, so that a small-diameter tree, a thinned wood, and a low-density wood can be used without using a long and long lumber product. In addition, since the strand shape is within an appropriate range, a woody material that can be used for structural applications can be provided without requiring a long strand manufacturing apparatus.

According to a fifth aspect of the present invention, in the method for producing woody material, the adhesive is hardened in a state where the strands are compressed at the time of heating, the whole is integrated, and the density is made higher than that of the raw wood, and then the high-temperature and high-pressure steam is used. Since the compression-restoring stress is reduced by processing to reduce the compression-restoring ratio to 5% or less, the drying shrinkage and expansion due to aging, which is a problem in a normal lumber product, is reduced to a level that does not substantially cause a problem, and the normal re-heating is performed. Since the moisture absorption / expansion which is a problem in the configuration EW is very small, it is possible to provide a woody material suitable for high temperature and high humidity in Japan.

According to the method for manufacturing a woody material according to the sixth aspect, since the raw wood is compressed by 10% or more, a woody material capable of securing sufficient strength can be provided. The method for producing a woody material according to claim 7 includes a step of compressing the strand to make it denser than the raw wood, a step of heating and curing the adhesive to integrate the whole, and a process using high-temperature and high-pressure steam. The step of reducing the compression restoring stress and reducing the compression restoring rate to 5% or less is performed during a single mold clamping cycle of the press, so that the woody material can be obtained with high productivity.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a holding time in a high-temperature and high-pressure state and a temperature in a method for manufacturing a woody material according to the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2B241 DA01 DB15 2B250 AA01 AA05 AA06 BA05 BA09 CA11 DA04 EA01 EA13 FA03 FA13 FA21 FA31 FA37 FA46 HA01 2B260 AA12 AA20 BA01 BA20 CB01 CD02 CD03 CD04 DA01 DA05 DD02 EA05 EB05 EB05 EB05 EB05 EB05 EB19 EB21 EB42 EC18

Claims (7)

[Claims] 1. A wood material in which a plurality of wood strands are integrated and bonded and integrated with each other, wherein said strands have a width of 5-100 mm, a thickness of 0.1-5 mm and an average length. Woody material characterized by being 150-200mm. 2. The wood material according to claim 1, wherein the wood material has a higher density than the raw wood and has a compression recovery ratio of 5% or less. 3. The wood material according to claim 1, wherein the wood material is compressed by 10% or more with respect to the raw wood. 4. The width of wood is cut, cut or split.
5-100mm, thickness 0.1-5mm and average length is 150-20
A strand shape of 0 mm, an adhesive is applied to this wood strand, and a plurality of the strands are integrated into a mat shape.
2. The method according to claim 1, wherein the mat is pressurized and heated to harden the adhesive and integrate the whole. 5. After the strand is compressed at the time of heating, the adhesive is cured to integrate the whole, and the density is made higher than that of the raw wood, and then treated with high-temperature and high-pressure steam to reduce the compression restoring stress. The method for producing a woody material according to claim 4, wherein the compression / restoration ratio is 5% or less. 6. The method according to claim 4, wherein the raw wood is compressed by 10% or more. 7. A step of compressing the strand to make it denser than the raw wood, a step of heating to cure the adhesive and integrating the whole, and a treatment with high-temperature and high-pressure steam to reduce the compressive restoring stress. The process of reducing the compression / recovery ratio to 5% or less is
7. The method for producing a woody material according to claim 6, wherein the method is performed during a cycle of mold clamping.