CN-118181436-B - Preparation method of formaldehyde-free low-carbon wood composite material

Abstract

The invention discloses a preparation method of an aldehyde-free low-carbon wood composite material, which comprises the steps of preparing impregnating solution, removing lignin on wood by using alkaline solution to obtain a wood matrix, pretreating the obtained wood matrix by adopting a gas phase treatment process to control and regulate pores on the wood matrix, carrying out cyclic freezing impregnation treatment on the wood matrix by using the impregnating solution, heating the wood matrix after S3 treatment, carrying out ultraviolet curing, and carrying out gas phase treatment to enable the pores on the wood after lignin removal to be more uniform, so that the impregnating solution is easier to impregnate in the impregnation process in the later stage, the occurrence of the condition that all areas cannot be filled is avoided, the uniformity of the pores is greatly improved, and the physical property and stability of the wood are improved while the impregnation degree and impregnation efficiency in the impregnation process in the later stage are improved.

Inventors

• GE SHENGBO
• ZHANG MINGLONG
• SHI YANG
• Ma Tonghua
• LU TONGHUA
• WEI RENZHONG
• XIE XIAOBING
• TANG ZHENZHONG
• HUANG RUNZHOU
• JIA LI

Assignees

• 南京林业大学

Dates

Publication Date

20260512

Application Date

20240424

Claims (5)

1. 1. The preparation method of the formaldehyde-free low-carbon wood composite material is characterized by comprising the following steps of: S1, preparing impregnating solution, and removing lignin on wood by using alkaline solution to obtain a wood matrix; s2, pretreating the wooden substrate obtained in the step S1 by adopting a gas-phase treatment process, so as to control and regulate the pores on the wooden substrate; S3, carrying out cyclic freezing and dipping treatment on the wood matrix by using a dipping solution, and carrying out heating treatment and ultraviolet curing on the wood matrix after the treatment of S3 to obtain a wood composite; in the step S1, the impregnating solution consists of a high molecular monomer, an initiator and a crosslinking agent; in the step S2, the gas phase treatment method comprises the steps of placing the lignin-removed wood substrate in a vacuum furnace, and introducing inert gas into the vacuum furnace to control the uniformity of pores of the wood substrate; The inert gas is one or two of steam, argon and nitrogen, the gas phase treatment parameters are that the temperature is 100-200 ℃, the pressure is 95-105kpa, and the time is 5-15h; in the step S3, the cyclic freezing and dipping treatment is specifically that the wooden substrate after the gas phase treatment is placed in a dipping tank with a circulating system and a freezing function, and dipping liquid is continuously circulated in the dipping tank; The parameters of the circulating freezing soaking treatment are that the temperature is between 15 ℃ below zero and 25 ℃, the soaking time is 20 to 30 hours, and the circulating speed is 5L/min to 15L/min; The heating treatment parameters are that the temperature is 65-80 ℃ and the time is 2-4h.
2. 2. The preparation method of the formaldehyde-free low-carbon wood composite material according to claim 1, wherein in the step S1, the alkaline solution is a solution formed by mixing sodium hydroxide, sodium carbonate or ammonia water with water, the concentration is 2% -4%, and the treatment time is 15-20h.
3. 3. The method for preparing the formaldehyde-free low-carbon wood composite material according to claim 1, wherein the high-molecular monomer is one of methyl methacrylate, ethyl acrylate and butyl acrylate, the initiator is one of acetyl peroxide, benzoyl peroxide and propionyl peroxide, and the cross-linking agent is one of melamine formaldehyde resin or glycerol triacrylate.
4. 4. The preparation method of the formaldehyde-free low-carbon wood composite material is characterized in that the impregnating solution is prepared by mixing 60-80% of high-molecular monomer, 1-5% of initiator and 10-30% of cross-linking agent by mass percent, and the impregnating solution is prepared by stirring and mixing the high-molecular monomer, the initiator and the cross-linking agent.
5. 5. The method for preparing the formaldehyde-free low-carbon wood composite material according to claim 1, wherein in the step S3, the mode parameter of ultraviolet curing is that the ultraviolet wavelength is 200-400nm and the irradiation time is 20-50min.

Description

Preparation method of formaldehyde-free low-carbon wood composite material Technical Field The invention relates to the field of preparation of wood composite materials, in particular to a preparation method of an aldehyde-free low-carbon wood composite material. Background As a novel environment-friendly material, wood composite materials have been widely used in various fields in recent years. The method takes wood as a base, realizes the optimization and improvement of the performance of the wood through the combination with other materials, and meets the requirements of the modern society on high-performance and environment-friendly materials. However, as the range of use of wood composite materials is expanded, problems such as formaldehyde release problems and curing unevenness during the freeze impregnation process are also gradually developed. The wood composite material has unique performance advantages and is widely applied to industries such as automobiles, buildings, indoor and outdoor decorations, household appliances, transportation and the like. In the automotive field, wood composite materials are used for manufacturing body parts and interior trim, so that the overall weight of an automobile is reduced, the fuel efficiency is improved, and design elements are added to the interior of the automobile. In the field of construction, wood composite materials are widely used for manufacturing parts such as doors, windows, walls and the like due to good heat preservation performance and environmental protection characteristics. In addition, in the indoor and outdoor decoration and household appliance industries, wood composite materials are also widely popular due to the characteristics of beautiful appearance, durability and the like. However, with the widespread use of wood composites, formaldehyde emissions have also become a concern. Formaldehyde is a common indoor air pollutant and long-term exposure to high-concentration formaldehyde environments can cause harm to human health. The use of adhesives is a major source of formaldehyde emissions in the manufacture of wood composites. Although low formaldehyde or formaldehyde-free adhesives are currently available, their use is not widespread due to cost and technical limitations. Therefore, how to reduce the formaldehyde content in the wood composite material and reduce formaldehyde release is a current problem to be solved. In addition to the formaldehyde problem, wood composites have the problem of non-uniform curing during the freeze impregnation process. The freezing impregnation treatment is a common modification method of the wood composite material, and the material performance can be further improved through the impregnation treatment under the low-temperature condition. However, in the actual operation process, due to the complex pore structure of the wood itself, the penetration and diffusion of the impregnation liquid in the wood tend to be uneven, resulting in a difference in the properties of the cured material. The non-uniform curing not only affects the overall performance of the wood composite material, but also can cause problems such as cracking, deformation and the like in the use process. Disclosure of Invention The invention overcomes the defects of the prior art and provides a preparation method of an aldehyde-free low-carbon wood composite material. In order to achieve the purpose, the technical scheme adopted by the invention is that the preparation method of the formaldehyde-free low-carbon wood composite material comprises the following steps: S1, preparing impregnating solution, and removing lignin on wood by using alkaline solution to obtain a wood matrix; s2, pretreating the wooden substrate obtained in the step S1 by adopting a gas-phase treatment process, so as to control and regulate the pores on the wooden substrate; and S3, carrying out cyclic freezing and dipping treatment on the wood matrix by using the dipping liquid, and carrying out heating treatment and ultraviolet curing on the wood matrix after the treatment of S3 to obtain the wood composite. In a preferred embodiment of the invention, in S1, the impregnating solution is composed of a high molecular monomer, an initiator and a cross-linking agent, the alkaline solution is a solution formed by mixing alkaline substances such as sodium hydroxide, sodium carbonate, ammonia water and the like with water, the concentration is 2-4%, and the treatment time is 15-20h. In a preferred embodiment of the present invention, the polymer monomer is one of Methyl Methacrylate (MMA), ethyl Acrylate (EA) and Butyl Acrylate (BA), the initiator is one of acetyl Peroxide (PA), benzoyl Peroxide (BPO) and Propionyl Peroxide (PPA), and the crosslinking agent is one of melamine formaldehyde resin (MF) or Glycerol Triacrylate (GTA). In a preferred embodiment of the invention, the impregnating solution is prepared by mixing 60-80% of high molecular monomer, 1-5% of initiator and