Plywood is a multi-layered board material made of veneer spun from wood segments or thin wood planed from wood squares and glued together by adhesives, and is one of the common materials for furniture. However, most of the traditional wood adhesives are synthetic resin adhesives, synthetic resin adhesives contain large amounts of free formaldehyde, which not only causes air pollution, but also poses a great danger to people's health.
Due to the rapid development of the economy, people's environmental awareness and quality of life, the elimination of formaldehyde gas caused by the growing demand for harm. Looking for new raw materials for wood-based panel, the development of green, environmentally friendly wood-based panel, has become a hot issue of the current wood industry.
First, what is glueless plywood?
Glue-free plywood is a kind of synthetic resin adhesive without external traditional, relying mainly on the material itself contains chemical composition under specific process conditions to achieve "self-bonding" and bonding into the material technology. The principle is through a special treatment method so that the surface of the plant fiber raw material activation, while producing similar to the adhesive material and make the material to be glued under hot pressing conditions into a plate.
1. Oxidation bonding method
Activation of the wood surface occurs after oxidation treatment with oxidizing agents, forming a loose, plastic active layer, followed by uniform dispersion of fillers or cross-linking agents on the surface of the wood-based material, and finally gluing into plates under hot press conditions. Commonly used oxidizers are nitrate, nitrate, hypochlorite, perchlorate, chromate, pertechnetate and ozone.
2. Free radical initiation method
Free radical initiation is the use of chemical or physical methods to activate the surface of the wood to produce free radicals, with free radicals on the two surfaces at a distance of the free radicals to reach the range of action of the two radicals, the lone electron pairing of the two free radicals, the polymerization reaction glued into the board when the heat pressure. Commonly used treatment agent is mainly peroxide and some salts containing iron ions.
3. Acid-catalyzed polycondensation
Acid has a strong destructive effect on wood, the use of sulfuric acid can degrade the cellulose and hemicellulose in wood, the degradation products of dehydration and the formation of glycolytic substances, this material in the hot pressure conditions can produce a polymer can act as a glue, thus gluing wood. Commonly used acid for sulfuric acid.
4. Natural substance transformation method
Natural substance conversion method uses the inherent material of wood itself or external natural substances, in specific process conditions through chemical conversion into a new substance with a gluing effect, in the hot pressing conditions to achieve their own gluing. This glueless board process is not only applicable to wood fiber materials, but also some non-wood fiber raw materials such as corn stalks, cotton stalks and so on.
1. Environmental safety
Plywood is mainly made of natural materials as raw materials, with very few chemical products such as resin adhesives, which are free of harmful substances such as formaldehyde.
2. Wide range of application
Compared with the synthetic resin production of wood-based panels, glue-free plywood due to environmental protection, non-toxic, fireproof, anti-corrosion and thermal insulation and other excellent performance, its use is very wide.
First of all, plywood is added to the natural substances mixed with fire retardant, with excellent fire performance, can effectively inhibit the fire process, can be applied to high temperature, dry places. Secondly, the corrosion resistance of glueless plywood is significantly higher than that of synthetic resin plywood, which is suitable for the environment with strict requirements on anti-corrosion and anti-pest. Finally, compared with air-dried wood of similar density, glueless plywood has a small thermal conductivity, low thermal conductivity, so the thermal insulation performance is excellent, which can be used for floor mat, interior wall decorative panels and other thermal insulation building materials.
3. Low production costs
Synthetic resins are expensive to produce and are used in large quantities. In the costing of shredded boards, the cost of synthetic resin adhesive accounts for about half of the total cost of shredded production. And this plywood board making process without the use of synthetic resin glue, so that production costs are greatly reduced, compared with the previous production process, production costs can be reduced by 15% -25%.
4 simple production process
The glueless process eliminates the need for adhesives, so the gluing and blending process is eliminated in the manufacture of chipboard, as well as the pre-curing of the adhesive and the sanding process. This not only simplifies the production process, but also saves manpower and material resources.
Large-scale production of plywood can not only alleviate the contradiction between supply and demand of wood resources, reduce the consumption of forest resources, protect the human ecological environment, but also solve the problem of free formaldehyde pollution of interior decoration and furniture, in line with the current national policy of creating a resource-saving, environment-friendly society, with good ecological benefits and social benefits.
Post time: Nov-17-2020