JP6820017B2 - Resin-coated bamboo and its manufacturing method - Google Patents

Description

The present invention relates to a resin-coated bamboo whose surface is coated with a resin and a method for producing the same.

Currently, due to the declining population, the forests and bamboo grove in the mountainous areas are not well maintained. The increase in abandoned and devastated bamboo grove is remarkable. From this point of view, the utilization of bamboo materials can be recognized as an urgent issue.
Bamboo (bamboo) is a general term for species of Poales, Poales, Bambusoideae, whose stems become woody, such as woody plants. Unlike normal wood, it does not grow secondary to hypertrophy, but bamboo is often regarded as wood in contrast to the closely related perfect herb.
Bamboo is divided into three types according to its growth type: bamboo in a narrow sense, bamboo grass, and bamboo. Bamboo rods that have been cut and dried are tough, easy to work with, and have abundant elasticity that wood does not have, so they are widely used as materials for products that require springiness, such as Japanese bows and fishing rods. It has been. Since the bamboo rod has a hollow inside, it has a strong property as a tube. It is a supple and strong material. Moreover, it is composed of elongated fibrous cells, which are also tubes. Therefore, it is particularly strong against pulling. However, the force from the side tends to cause the pipe to break. Also, it is not suitable for supporting weighting. Depending on the situation, it can be used as it is or in the form of a thin plate. The one crushed from the side is also used like a rope. The thinner rods are called bamboo strings and are used as materials for bamboo baskets. The rod is almost columnar and hollow, lightweight, durable and good. Therefore, there are special use cases such as fishing rods and pole vault rods. If you cut it to a certain length and pierce the partition in the middle, you can make a pipe. It is also used to cut this in half vertically and let water flow. If the bamboo is not cut or one knot is left as it is, it becomes a closed container. Easy to obtain and easy to sharpen and bend. The direction of the fiber is clear, and it is easy to break it into small pieces along the direction. Since cracking stops at the knots, it is easy to mass-produce rods of the same quality and length. If you cut it thinly and thinly, you can obtain a tip with appropriate elasticity depending on its thickness. Furthermore, it is relatively resistant to corrosion and easy to store even in the unprocessed state. It is often used for crafts and crafts, and is often used as a material for traditional crafts in various regions. As the days go by, the felled green bamboo gradually begins to reduce its color, becomes depleted, and cracks occur. Eating damage by bamboo insects and mold may occur depending on the surrounding environment. Specifically, the Aotake body begins to reduce its color in about a week in direct sunlight. Bamboo begins to contract in about 4 to 5 hours and leaves fall after a week. It will be exhausted in about half a year depending on the weather. After it is completely depleted, cracks gradually occur. In addition, bamboo insects cause feeding damage inside the bamboo. In addition, mold is generated by temperature and humidity. Research has been conducted on these, but no effective measures have been obtained.

On the other hand, as a method for increasing the strength of green bamboo, the method described in Patent Document 1 has been conventionally proposed. In this method, the cut bamboo material is treated with boiling water for a long time, then immersed in a synthetic resin solution, dried, and then coated with a two-component urethane resin. The purpose is to strengthen the material (prevent cracking), prevent bark from coming off, and prevent discoloration.

Japanese Unexamined Patent Publication No. 8-39515

However, in such a conventional technique, since urethane resin is applied to the surface of dried bamboo, its strength can be increased to some extent, but it is still not sufficient, and its biggest problem is. The process of hot water treatment, drying, and resin coating was complicated, and the manufacturing cost had to be excessive. In addition, the original surface color of bamboo could not be maintained by the hot water treatment.

Therefore, as a result of diligent research, the inventor made a resin solution containing a water-soluble resin sucked up from the cut end of the bamboo material immediately after cutting to form a film of the water-soluble resin on the surface and to form a vessel inside the structure of the bamboo material. By obtaining a resin-coated bamboo filled with a water-soluble resin, all the above-mentioned problems have been solved.

That is, an object of the present invention is to provide a high-strength bamboo material having excellent crack / crack prevention, mold prevention, food damage avoidance, and fading property, which can be sufficiently used as a building material in addition to a daily necessities material, for example. There is.

The invention according to claim 1 is a resin-coated bamboo in which the surface of the bamboo material is coated with the water-soluble resin by sucking up a resin solution containing a water-soluble resin from the cut end of the bamboo material . It is a resin-coated bamboo containing 2 to 10% by weight of a water-soluble resin and a liquid agent further containing an ion-oriented resin, a glass-based polymer, silicone, water, and a surfactant .
The type of bamboo material does not matter. Matake, Hontake, Meng Soutake, etc. The water-soluble resin needs to be able to be sucked up from the cut end of the bamboo material. For example, it is a resin solution in which a vinyl acetate resin solution, an acrylic resin solution, a polyvinyl chloride resin solution, a vinyl acetate resin solution, an acrylic resin solution, or the like having a predetermined concentration is mixed. The water-soluble resin contains a hydrophilic group (OH group, COOH group, NH2 group, SO3 group, etc.) in the polymer.
Examples of the water-soluble resin composition include a mixture of polyvinyl alcohol and a terpene-maleic anhydride copolymer resin.
The bamboo material may be an oblique cut that is perpendicular to the extending direction of the vegetated bamboo material or is inclined by a predetermined angle. One end of the vascular bundle (vessel element, phloem tube) is cut and exposed in the tissue of the cut end, which is the cut surface. Alternatively, the bamboo material may be further processed into a semi-cylindrical body or a strip shape instead of a cylindrical body.

In the invention according to claim 2, the vegetated bamboo material is cut out, and the bamboo material immediately after cutting is immersed in the resin solution for a predetermined time with the cut end exposed in a resin solution containing a water-soluble resin having a predetermined concentration. by, fulfills resin solution on the road canal siphoned resin solution from vessel of the bamboo, a resin coating bamboo coated with coating according to this water-soluble resin on the surface of the bamboo, the resin solution , A resin-coated bamboo containing 2 to 10% by weight of a water-soluble resin and a solution containing an ion-oriented resin, a glass-based polymer, silicone, water, and a surfactant .
Immediately after cutting the bamboo material, the cut end is immersed in a resin solution containing a water-soluble resin. If the cut is dry, make a new cut to form a new cut.
Although there are uncertain factors such as the immersion time fluctuating depending on the season, the immersion time is set to 6 hours or more until the suction stops, for example, 24 hours. During that time, it is desirable to stir the resin solution at regular intervals (for example, 2 hours). This is to prevent resin separation. The resin solution to be used is not limited to a single type, and may be a mixture of a plurality of types of resin solutions.

The resin solution contains liquid car wax .
As a liquid car wax, for example, there is a trade name "Zymol", which uses a plant-based oil as a solvent for a vegetable resin called Carnauba, which is a raw material of a film. Further, as a liquid car wax that can be used, the trade name "Urban Shine BODY WAX" is a spray type, weakly acidic, and contains an ion-oriented resin, a glass-based polymer, silicone, water, and a surfactant as its components.

According to the third aspect of the present invention, a vegetated bamboo material is cut out, and the bamboo material immediately after cutting is immersed in the resin solution for a predetermined time with the cut end exposed to a resin solution containing a water-soluble resin having a predetermined concentration. This is a method for producing a resin-coated bamboo, which sucks up the resin solution from the canal of the bamboo material to fill the canal with the resin solution and coats the surface of the bamboo material with a film of the water-soluble resin. The resin solution is a method for producing a resin-coated bamboo containing 2 to 10% by weight of a water-soluble resin and further containing a liquid agent containing an ion-oriented resin, a glass-based polymer, silicone, water, and a surfactant. ..
Immediately after cutting the bamboo material, the cut end is immersed in a resin solution. If the cut is dry, make a new cut to form a new cut. By immersing this cut end in a resin solution (including a water-soluble resin), suction becomes possible. The resin includes a water-soluble resin. Specifically, an aqueous solution of vinyl acetate resin, an aqueous solution of acrylic resin, or the like is applied. Cut at a cut end that is inclined at, for example, 30 to 45 degrees with respect to the extending direction of the bamboo (rod). The vascular bundle is exposed on the cut surface. The vascular bundle is dense on the outside (epidermis side) in the radial direction and sparsely distributed on the inside (inner air side).
The immersion time in the resin solution containing the water-soluble resin has uncertain factors such as fluctuation depending on the season, but it is, for example, until the suction disappears after 6 hours or more, for example, until 24 hours have passed. During that time, it is desirable to stir the resin solution at regular intervals (2 hours). This is to prevent resin separation.

The above resin solution contains 2 to 10% by weight of a water-soluble resin with respect to the entire solution.
As the resin solution, in addition to the resin solution containing a single type of water-soluble resin, a resin solution in which a plurality of types of water-soluble resins are mixed can also be used. The concentration of the resin solution is preferably 6 to 8% by weight, for example, for vinyl acetate resin. It is important that the viscosity of the solution is optimal for suction.

The invention according to claim 4 is the method for producing a resin-coated bamboo according to claim 3, which contains a vinyl acetate resin or an acrylic resin as the water-soluble resin.

The resin solution contains liquid car wax.
The water-soluble resin is easier to handle than other resin solutions using, for example, alcohol as a medium. When a water-soluble resin is used, when glass-containing car wax is mixed with it, the surface of the coated bamboo becomes the same state as polymer processing, and it is less affected by humidity than without wax, it is hard to crack, and mold is generated. Has the effect of preventing.

According to the inventions of claims 1 and 2, the surface of bamboo is coated with resin, and the vascular bundle (vessel element, etc.) of the internal structure of bamboo is filled with resin, so that the bamboo material (bamboo rod) ), The mechanical strength is increased. Therefore, it can be effectively used as various building materials. In addition, it is possible to prevent fading of the surface thereof, prevent the generation of mold, easily remove stains, and prevent feeding damage, and it is extremely useful as an interior decoration material and a material for daily necessities.
According to the inventions of claims 3 to 4, a resin-coated bamboo in which the canal in the bamboo tissue is filled with a water-soluble resin or the like and the bamboo surface (skin) is coated with the water-soluble resin is efficiently produced. Can be done.
Vinyl acetate resin, which is one of the water-soluble resins, is easily sucked up by bamboo.
The felled bamboo does not crack due to color reduction or depletion. When the bamboo itself sucks up the resin solution, the water and oil contained in the bamboo tissue are pushed out from the bamboo surface. For example, the water-soluble resin oozes out on the bamboo surface to form a hard resin film on the bamboo surface. It is considered to be. The increase in the strength of the bamboo itself was confirmed by a test.
Bamboo bamboo leaves also have a resin film formed at the base, which increases their strength and makes it difficult for the leaves to fall. Color reduction can also be prevented.
In particular, the influence of humidity could be eliminated by mixing, for example, a car wax containing a glass component or the like with a water-soluble resin. As a result, it is hard to crack and the generation of mold can be prevented. In addition, it is possible to increase the strength and prevent fading.

It is a schematic diagram which shows the relationship between the cut end of green bamboo and the resin solution at the time of sucking up the resin solution which concerns on this invention, (A) shows the state at the time of single-sided inclined cutting, and (B) shows the state at the time of double-sided inclined cutting. It is sectional drawing which shows the internal structure of the bamboo after sucking up the resin which concerns on embodiment of this invention in the state which a part of the epidermis is peeled off. It is a vertical cross-sectional view of a part of bamboo showing the internal structure of bamboo in a state where a part of the epidermis is peeled off as in FIG.

Hereinafter, examples of the present invention will be described.
For the sample to be used, the vegetated bamboo material is cut out, and the bamboo material immediately after cutting is immersed in this resin solution with the cut end exposed in the resin solution containing a water-soluble resin. This resin solution was sucked up from the surface to fill the canal with the resin solution, and the surface of the bamboo material was coated with a film of the water-soluble resin to process a resin-coated bamboo.
At this time, a resin solution containing a water-soluble resin (vinyl acetate resin, acrylic resin) containing 2 to 10% by weight of the water-soluble resin with respect to the entire solution may be used. In addition, the above resin solution can contain liquid car wax, which is a spray type, weakly acidic under the following trade name "Urban Shine BODY WAX", and its components are ion-oriented resin and glass-based polymer. , Silicone, water, surfactant included.

1) Manufacture of resin solution Commercially available woodworking glue (manufactured by Konishi Co., Ltd.) is used. It contains 41% vinyl acetate resin and 59% water. 2000cc to 2400cc of water is added to 400cc of this woodworking glue to prepare a water-soluble vinyl acetate resin solution. The concentration of acetic acid resin is 6.25% by weight to 7.41% by weight.
2) Cutting and cutting of bamboo As shown in FIGS. 1A and 1B, the vegetated bamboo material is cut out at an angle to the bamboo material 10, that is, so that the cut end is an inclined surface 10A. Alternatively, after the horizontally cut bamboo material 10 is conveyed, the cut end portion is cut diagonally to make the cut end an inclined surface 10A. The bamboo leaves may or may not be removed. Bamboo with a predetermined diameter (for example, about 20 cm) is cut out from the bamboo grove of Moso bamboo that grows in clusters in the Nakahanda district of Oita City, Oita Prefecture.
Immediately after cutting (about 1 to 2 hours after cutting), the bamboo material 10 is placed in a bucket 11 filled with the vinyl acetate resin solution, and the cut end 10A at the lower end of the inclined cut bamboo material is exposed to the resin solution. Immerse in the solution for a predetermined time (variation varies depending on the season for about 6 to 12 hours). As a result, the bamboo material sucks up the resin solution from its internal structure, that is, the canal, and fills the canal 10B inside the bamboo with the resin 12. A vinyl acetate resin film 12 having a predetermined thickness (for example, 10 to 500 μm, but varies depending on the viscosity of the resin solution) is formed on the surface of the bamboo material 10. That is, it is a resin-coated bamboo whose surface is coated with a transparent resin film 12. As shown in FIGS. 2 and 3, the inside of a large number of vessels 10B in the tissue is filled with the resin 12A.
Further, as the resin, a vinyl acetate resin having a predetermined concentration was used.
Although acrylic resin is sucked up, its hardness tends to be insufficient as compared with vinyl acetate resin. In addition, the bamboo surface coating becomes opaque.
Furthermore, it was confirmed that the suction is possible even if a synthetic resin (the main component of the water-soluble varnish) is used.
The vinyl acetate resin solution has a good suction condition, and a transparent film 12 having a predetermined thickness is formed on the surface thereof. The same effect can be obtained with a polyvinyl chloride resin solution.

Hereinafter, the property test of the resin-coated bamboo thus produced will be specifically described.
1) For the mechanical strength test, a bending tester (AGS-J10KN manufactured by Shimadzu Corporation) owned by the Oita Industrial Research Institute, located at 1-4364-10 Takaenishi, Oita City, was used for the bamboo material subject to the strip shape. I went using it.
The test conditions are a distance between fulcrums (span) of 100 mm, a lowering speed of the pressing head of 10 mm / sec, an elastic modulus of 10 to 50 N, and drying of the untreated material in 3 days. The treated material to be tested has a cross section of 4 to 5 mm in thickness, 10 mm in width, and 15 to 20 cm in length like the untreated material, and both the treated material and the untreated material are one (same) bamboo material. It was prepared by cutting out the internode parts from each of them.
As shown in FIG. 1 (A) or (B), the felled bamboo (main bamboo) is tilted by a predetermined angle with respect to the length direction of the bamboo material (not 90 degrees). ) Disconnect.
The container is placed in a bucket-like container filled with a vinyl acetate resin solution with the cut surface facing down. The end of the bamboo material on the cut side is completely immersed in the solution so that the inclined cut surface is exposed in the solution. The resin solution of the water-soluble resin is sucked up by the bamboo material from the cut surface through the canal.
As a result, as shown in FIGS. 2 and 3, it can be seen that the vessel of the internal structure of the bamboo material is filled with resin. In addition, a resin film is transparent and hard (solidified) on the surface of the bamboo material. During the suction, the mixture is stirred every 30 minutes to 2 hours to prevent the water-soluble resin from separating.
As the resin solution, a commercially available woodworking glue (vinyl acetate resin 40% water 60%) diluted with water was used.
Table 1 shows the results of the strength test.
As is clear from this, it was found that the bending strength of the bamboo material increased.

Since the water content of the treated material is higher than that of the untreated material, it is considered that the strength of the treated material is higher than that of the untreated material.

2) Discoloration test Table 2 shows the discoloration data of the resin-coated bamboo under direct sunlight.

In places where it is directly exposed to ultraviolet rays, the return color of the bamboo surface changes from around 150 days, and it turns brown after 360 days. There is no change in dirt on the front and back. Bamboo leaves begin to fall lyrically around 180 days and completely fall around 270 days.

Table 3 shows the discoloration data in the room.

Since it is not affected by ultraviolet rays indoors, the green change on the bamboo surface becomes slightly lighter than after about 10 months. It is equivalent to the time of felling. No change is observed in the dark room. Dirt can be removed by wiping with a waste cloth because the dirt contains bamboo oil. There is no fallen leaves on bamboo leaves.

Next, it is generally said that the strength of bamboo knots is weak (compared to the bamboo body part that does not contain knots). Therefore, an experiment was conducted to see if the strength of the bamboo material containing knots could be increased by impregnating the resin solution and coating the surface according to the present invention.

3) Next, the following test was performed using the above-mentioned testing machine "SHIMADZU AGS-J 10kN". First, a tensile test was conducted on bamboo material containing knots (matake produced in the above-mentioned production area).
Secondly, a bending test was conducted on bamboo materials containing knots (Matake from the same production area). As the coating agent, 5 ml of vinyl acetate resin, 10 ml of acrylic resin, and 15 ml of glass-containing wax (clean view glossy body wax (trade name)) were used for 1 liter of water. The coating method was the same as in the above examples.
Table 11 shows the specifications of the uncoated knotted sample.

表１２はコーティング処理が施された節つきサンプルの諸元を示す。

Table 12 shows the specifications of the coated knotted sample.

表１３は、未処理サンプル（節つき）の引っ張り強度試験結果を示す。

Table 13 shows the tensile strength test results of the untreated sample (with knots).

表１４は、処理済みサンプル（節つき）の引っ張強度試験結果である。

Table 14 shows the tensile strength test results of the treated sample (with knots).

Regarding the tensile strength test, when the breaking condition was visually confirmed, the bamboo sample was held at both ends, so the external force when the bamboo sample was split vertically along the bamboo streaks was set as the maximum tensile force. It was confirmed that no fracture occurred at the knots and that the knots had high strength. In this case, it was confirmed that the coated sample had higher tensile strength than the untreated sample.
Table 15 shows the bending strength test results of the untreated sample (with knots).

表１６は、処理済みサンプル（節つき）の曲げ強度試験結果である。

Table 16 shows the bending strength test results of the treated sample (with knots).

未処理サンプルに対して、コーティング処理を施したサンプルは、２６％程度高強度であることが確認できる。なお、曲げ試験におけるサンプルを水平支持する２つの支点の支点間距離は２００ｍｍである。
表１７は、未処理サンプル（節なし）の曲げ強度試験結果である。

It can be confirmed that the coated sample has about 26% higher strength than the untreated sample. The distance between the fulcrums of the two fulcrums that horizontally support the sample in the bending test is 200 mm.
Table 17 shows the bending strength test results of the untreated sample (no knots).

表１８は、処理済みサンプル（節なし）の曲げ強度試験結果を示す。

Table 18 shows the bending strength test results of the treated sample (no knots).

これら表に示すように、支点間距離２００ｍｍでの曲げ試験では、処理済み品が６０％程度の強度アップが認められる。なお、乾燥率は７．７％程度とされる。

表１９は、未処理サンプル（節なし、竹下部より６ｍの高さ部位のサンプル）の曲げ強度試験結果である。

As shown in these tables, in the bending test at a distance between the fulcrums of 200 mm, the strength of the treated product is increased by about 60%. The drying rate is about 7.7%.

Table 19 shows the bending strength test results of the untreated sample (no knot, sample at a height of 6 m from the lower part of the bamboo).

表２０は、処理済みサンプル（節なし、竹下部より６ｍ高さ部位）の曲げ強度試験結果である。

Table 20 shows the bending strength test results of the treated sample (no knots, 6 m above the bottom of the bamboo).

竹材サンプルを支点間距離２００ｍｍでの曲げ試験である。処理済みサンプルの方が未処理サンプルよりも１７％程度強度が高められたことが確認された。含水率は７〜８％の素材サンプルである。

This is a bending test of a bamboo sample at a distance between fulcrums of 200 mm. It was confirmed that the strength of the treated sample was increased by about 17% as compared with that of the untreated sample. The material sample has a water content of 7 to 8%.

4) Next, an experiment was conducted on the coloring state in the coating treatment on bamboo material. In addition to the above coating agent, the ink of a printing printer was used to make bamboo suck it up. A bamboo material with bamboo grass was cut in the same manner as described above, a container was filled with a mixed solution of the above coating agent and printer ink for printing, and the cut surface was dipped in the mixture to obtain a coloring test. Coloring could be confirmed visually on the surface of the bamboo leaves and the canal part of the bamboo material.
Further, in this treatment test, the color faded in about 2 weeks without treatment, but in the case of treated, no fading was observed in about 3 months.
As a printing ink that can be used in this test, there is an in-line water-based coating composition for an offset printing machine, which contains a water-soluble resin and a cross-linking agent. In this case, the water-soluble resin is selected alone or in plurality from acrylic resin, styrene-acrylic resin, styrene-maleic acid resin, urethane resin, epoxy resin, polyester resin, amide resin and copolymer resin of these resins. .. The cross-linking agent is selected from a blocked isocyanate compound, a compound containing a carbodiimide group, a compound containing an oxazoline group, a compound containing a hydrazide group, an epoxy compound, and an organic metal compound.

Further, the cut surface of the cut bamboo material dries when left for about 2 days, but the bamboo material can suck up the resin solution by cutting the interlude portion and immersing the surface containing water with a coating agent. Therefore, it was found that the felled bamboo material can be transported and coated at the factory. The felled bamboo materials can be aggregated and coated after 2 to 3 days. In addition, simultaneous processing of multiple bamboos is possible. It has become possible to improve work efficiency.

Regarding water-soluble resins, the coating treatment material may absorb moisture from the surface in high humidity environments such as rainy weather, but by mixing car wax containing glass components with the water-soluble resin, the influence of humidity is eliminated. We were able to. As a result, it is hard to crack and mold can be prevented.
It was also found that the whitening of bamboo leaves after coating was delayed in acrylic resin rather than vinyl acetate resin. Acrylic resin is suitable for maintaining green color.

According to the present invention, the coating treatment is useful for all kinds of bamboo materials. It was found that other materials belonging to the Poales, Poales, such as Japanese pampas grass and Miscanthus sinensis, can also be coated to increase their strength and prevent fading.

The resin-coated bamboo according to the present invention is useful as a building material, a material for crafts, and as a pipe / container.

Claims (4)

A resin-coated bamboo whose surface is coated with the water-soluble resin by sucking up a resin solution containing a water-soluble resin from the cut end of the bamboo material.
The resin solution is a resin-coated bamboo containing 2 to 10% by weight of a water-soluble resin, and further containing a liquid agent containing an ion-oriented resin, a glass-based polymer, silicone, water, and a surfactant . The vegetated bamboo material is cut out, and the bamboo material immediately after cutting is immersed in this resin solution for a predetermined time with the cut end exposed in a resin solution containing a water-soluble resin having a predetermined concentration. It is a resin-coated bamboo that sucks up this resin solution from the inside and fills the canal with the resin solution, and coats the surface of this bamboo material with a film of this water-soluble resin.
The resin solution is a resin-coated bamboo containing 2 to 10% by weight of a water-soluble resin, and further containing a liquid agent containing an ion-oriented resin, a glass-based polymer, silicone, water, and a surfactant . The vegetated bamboo material is cut out, and the bamboo material immediately after cutting is immersed in this resin solution for a predetermined time with the cut end exposed to a resin solution containing a water-soluble resin having a predetermined concentration. It is a method for producing a resin-coated bamboo that sucks up this resin solution from the surface to fill the canal with the resin solution and coats the surface of the bamboo material with the film of the water-soluble resin.
The above resin solution is a method for producing a resin-coated bamboo, which contains 2 to 10% by weight of a water-soluble resin and further contains a liquid agent containing an ion-oriented resin, a glass-based polymer, silicone, water, and a surfactant . The method for producing a resin-coated bamboo according to claim 3, further comprising a vinyl acetate resin or an acrylic resin as the water-soluble resin .

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