CN113664937A

CN113664937A - Method for reducing internal stress of wood

Info

Publication number: CN113664937A
Application number: CN202111056777.6A
Authority: CN
Inventors: 王书香; 郑可馨
Original assignee: Suzhou Haosheng Muyi Biotechnology Co ltd
Current assignee: Suzhou Haosheng Muyi Biotechnology Co ltd
Priority date: 2021-09-09
Filing date: 2021-09-09
Publication date: 2021-11-19

Abstract

The application discloses a method for reducing internal stress of wood, which comprises the following steps: (1) uniformly mixing 30-70 g of pentaerythritol with 1L of water, and putting the mixture into a wood block for impregnation, wherein the impregnation temperature is 25-45 ℃, and the impregnation time is 24-48 h; (2) taking out the wood blocks and putting the wood blocks into a blast drying box for drying; (3) taking out the wood blocks and putting the wood blocks into a vacuum drying box for drying; (4) repeating the step (3) for 3-5 periods. In the method, because the molecules of pentaerythritol contain a large number of hydroxyl groups, the pentaerythritol and cellulose can form hydrogen bonds, and can be effectively combined with the cellulose to enable the cell walls of the wood to be in an expanded state, so that warping and cracking are prevented.

Description

Method for reducing internal stress of wood

Technical Field

The application relates to the field of wood, in particular to a method for reducing internal stress of wood.

Background

The water on the surface of the wood evaporates quickly and the water content decreases first, causing the surface to begin to dry out. However, the moisture content of the inner layer of the wood is still high, and no simultaneous drying and shrinkage occurs, internal stress of external tension and internal compression is generated, and when the stress exceeds the tensile strength limit of the wood, the wood tissue is damaged to generate cracking. In addition, the dry shrinkage and wet expansion anisotropy (axial dry shrinkage of 0.1-0.3%, radial dry shrinkage of 3-6%, chord dry shrinkage of 6-12%) also causes warpage, cracking and the like in the drying process of the wood. Reducing internal stress in wood is an effective way to reduce cracking of wood, and many attempts have been made to improve dimensional stability of wood, and many have been successful, but no convenient and economical solution has been found to solve this problem. The wood is successfully inflated by using the inflating agent, and the inflating agent permeates into the cell walls of the wood, so that the cell walls of the wood are in an expanded state and do not shrink any more. Among the various inflation treatments, polyethylene glycol 1000(PEG1000) treatment, wood acetylation, and phenol resin treatment were most remarkably effective. PEG1000 moisture-absorption treatment is only suitable for special purposes. The acetylation of wood has not been put into production formally due to economic and technical problems. The phenolic resin-treated wood is used as a mold material, but the toughness of the wood is greatly reduced, so that the use is limited.

Disclosure of Invention

The invention aims to provide a method for reducing internal stress of wood so as to overcome the defects in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

the embodiment of the application discloses a method for reducing internal stress of wood, which is characterized by comprising the following steps:

(1) uniformly mixing 30-70 g of pentaerythritol with 1L of water, and putting the mixture into a wood block for impregnation, wherein the impregnation temperature is 25-45 ℃, and the impregnation time is 24-48 h;

(2) taking out the wood blocks and putting the wood blocks into a blast drying box for drying;

(3) taking out the wood blocks and putting the wood blocks into a vacuum drying box for drying;

(4) repeating the step (3) for 3-5 periods.

Preferably, in the method for reducing the internal stress of the wood, the dipping temperature in the step (1) is 25 ℃, and the dipping time is 36-48 h.

Preferably, in the method for reducing the internal stress of the wood, 50 to 70g of pentaerythritol is used in the step (1).

Preferably, in the method for reducing the internal stress of the wood, the drying temperature in the step (2) is 40 ℃, and the drying time is 24 hours.

Preferably, in the method for reducing the internal stress of the wood, the absolute pressure of the vacuum in the step (3) is-60 kp, the temperature is 80 ℃, and the vacuum is kept for 10-12 h.

Compared with the prior art, the invention has the advantages that:

in the method, because the molecules of pentaerythritol contain a large number of hydroxyl groups, the pentaerythritol and cellulose can form hydrogen bonds, and can be effectively combined with the cellulose to enable the cell walls of the wood to be in an expanded state, so that warping and cracking are prevented.

Detailed Description

The technical solutions in the embodiments of the present invention will be described in detail below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The method for reducing the internal stress of the wood in the embodiment comprises the following steps:

(4) repeating the step (3) for 3-5 periods.

Further, in the step (1), the dipping temperature is 25 ℃, and the dipping time is 36-48 h.

Further, 50-70 g of pentaerythritol is used in the step (1).

Further, in the step (2), the drying temperature is 40 ℃, and the drying time is 24 h.

Further, in the step (3), the absolute pressure of vacuum is-60 kp, the temperature is 80 ℃, and the temperature is kept for 10-12 h.

In the technical scheme, in the method, because molecules of pentaerythritol contain a large number of hydroxyl groups, the pentaerythritol and cellulose can form hydrogen bonds, and can be effectively combined with the cellulose to enable the cell walls of the wood to be in an expanded state, so that warping and cracking are prevented.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely a detailed description of the present application, and it should be noted that modifications and embellishments could be made by those skilled in the art without departing from the principle of the present application, and these should also be considered as the protection scope of the present application.

Claims

1. A method of reducing internal stress in wood, comprising the steps of: (1) uniformly mixing 30-70 g of pentaerythritol with 1L of water, and putting the mixture into a wood block for impregnation, wherein the impregnation temperature is 25-45 ℃, and the impregnation time is 24-48 h; (2) taking out the wood blocks and putting the wood blocks into a blast drying box for drying; (3) taking out the wood blocks and putting the wood blocks into a vacuum drying box for drying; (4) repeating the step (3) for 3-5 periods.

2. A method of reducing internal stress in wood according to claim 1, wherein: the dipping temperature in the step (1) is 25 ℃, and the dipping time is 36-48 h.

3. A method of reducing internal stress in wood according to claim 1, wherein: taking 50-70 g of pentaerythritol in the step (1).

4. A method of reducing internal stress in wood according to claim 1, wherein: and (3) drying at the drying temperature of 40 ℃ for 24h in the step (2).

5. A method of reducing internal stress in wood according to claim 1, wherein: and (3) keeping the absolute vacuum pressure of-60 kp and the temperature of 80 ℃ for 10-12 h.