JPS5859801A - Crack arrester for 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] Wood has been indispensable in the construction of houses in Japan since ancient times. Wood is made from trees felled from forests and classified into boards, groats, groats, etc., and is used according to its purpose.

When a tree is cut down, its cells contain a large amount of water, which gradually loses water over time. This evaporation and drying occurs on the surface of the wood and gradually progresses toward the center, but if the drying process is not appropriate.

Cracks occur in the wood, resulting in a so-called cracking phenomenon.

In other words, the cells that make up the wood structure maintain a high water content, but the moisture in the cells on the surface rapidly evaporates, creating internal stress between the cells in the center of the upper surface. (Because the wood shrinks faster than the cells), cracks in the wood occur. This crack also affects the strength of the wood.
Needless to say, it is also a drawback in terms of aesthetics, and various efforts have been made to prevent this.

For example, by drying wood slowly, the moisture in the cells from the surface to the center can be evaporated at the same rate, and the shrinkage state of the cells is evened out, so no cracks occur. Therefore, a method called sewarishi is used in which cracks are artificially created in the radial direction from the surface to the center of square timbers with cores and round logs to speed up the evaporation of moisture in the core parts. In addition, some of the high-quality maro logs are left to dry naturally in warehouses for about two years, and occasionally moisture is added to the surface of the logs to prevent them from drying out too quickly. However, even with this method, it is still not possible to achieve the necessary and sufficient effect.

Therefore, in recent years, some high-quality materials for residential use have a skin at on the surface of the sawn wood. This method involves applying a collection liquid to the surface of the wood to form a breathable film, thereby suppressing rapid water evaporation on the surface of the wood and gradually drying it.

However, in reality, it is often used during drying, so if you use a planer on the surface at a construction site, the film will be scraped off by the planer, and if it is further dried afterwards, it will prevent moisture evaporation. Can not do it. There remains the drawback that cracks occur in the construction.

The present invention eliminates the drawbacks of the conventional methods as described above, by applying an aqueous solution of coal to the surface of the wood, and by scraping it with a planer not only after drying but also during the drying process, this agent can effectively prevent cracks. The purpose is to provide.

To explain the embodiments of the present invention, first, the chemical properties of polyethylene glycol are that ethylene oxide is added to ethylene glycol or water, and its molecular weight is defined by the average molecular weight like all polymeric chemicals. ing.

In this example, a 30% water bath solution of polyethylene glycol, which has a molecular weight of 1000 and is water-replaceable and non-hygroscopic, is applied to the surface of the lumber after sawing.

In this case, it is more effective to soak materials like Maromaru-dai, which have smooth surfaces and are difficult for chemical solutions to penetrate, in an aqueous solution or wrap them in a cloth soaked in the solution and leave them for 4 to 5 hours. Just apply enough to wet the surface you want to prevent.

After applying the polyethylene glycol water bath solution to the wood in this manner, the wood was left to stand in 8 spaces.

8. The aqueous solution of this example is completely absorbed into the wood in about one hour, and after that, no solution comes out on the surface of the wood at room temperature.

To explain the process by which polyethylene glycol permeates into wood, polyethylene glycol Fi first diffuses into the free water contained in the large intercellular spaces in the wood due to the moisture in the wood and the concentration gradient of the polyethylene glycol aqueous solution. . Then, as the water in the cell and the aqueous solution try to reach an equilibrium state, the polymer diffuses into the inner NM cell membrane one after another from the point in contact with the polyethylene glycol aqueous solution through the thin cell layer tissue, and the degree of polymerization gradually increases. This continues until there is no more tilt. When diffused to its best conditions, wood absorbs up to 35X polyethylene glycol.

After that, during the drying process of the wood, evaporation of water starts from free water, and the cell JI and IIl of bolier and ethylene glycol further accumulates. Finally, only the polyethylene glycol is continuously diffused into the cell membrane and maintained in a stable state, so that even after the wood dries, it can maintain its swollen state when absorbing moisture (before drying), and no cracks will occur.

In this example, a 30% aqueous solution of polyethylene glycol was used;
The molecular weight is not limited to 1000 but can be selected within the range of 40.
It can be selected within the range of 0 to 7000. The effect of this example constructed and used as described above is that since the polyethylene glycol penetrates into the interior of the wood, it has a semi-permanent effect even on architectural ridges, and will not be affected even if the surface is scraped with a plane etc. First, it can be easily used when the moisture content of wood is high or low, and the aqueous solution penetrates in a short time, so it can quickly and quickly apply crack prevention to large quantities of lumber, giving it high value. I can do it.

As mentioned above, the purpose of the present invention is Fi.

1 of polyethylene glycol with a molecular weight of 400 to 7000
Since it is a wood crack prevention agent consisting of a 5% to 40% aqueous solution, it has a semi-permanent crack prevention effect with easy and quick work.Patent applicant: Kaho Aomori Patent Attorney 1) Junior High School 2 Department .

1 other person

Claims (1)

[Claims] Polyethylene glycol with a molecular weight of 400 to 7000
A wood crack prevention agent consisting of an aqueous solution of 5X to 40511'.