trends and prospects of aldehyde-free wood-based panel technology

In-depth analysis: trends and prospects of aldehyde-free wood-based panel technology

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“Reducing the amount of formaldehyde released” and “looking for new materials” have become two “big mountains” that stand in front of domestic wood-based panel companies. The new material is free from aldehyde wood-based panels

In fact, some forward-thinking companies in China have begun to explore the fields of “aldehyde-free wood-based panel technology” and “new type of alternative raw materials” in the late 1980s.

Taking the trend of patent applications for “aldehyde-free wood-based panels” (Figure 4) as an example, the increase in the number of patent applications in this area can be said to be accompanied by a gradual increase in consumer awareness of home-based environmental safety.

1. Patent application trend and technology life cycle of Chinese aldehyde-free wood-based panels

From statistical data, the development of “aldehyde-free wood-based panels” technology is roughly divided into two phases:

(1) The embryonic stage of technology (1989-2000): In the 1990s, research on soy protein-based adhesives promoted by the American Soybean Association made the field of biomass adhesives a new research hotspot. China’s aldehyde-free technology began in 1989 when Wang Chunlei studied plastic composites of waste plastics and plant fibers. The Chinese Academy of Forestry Sciences later studied the method of producing hard fiberboards using colloidal silica gel as a rubber compound. However, at this time, the Chinese people’s awareness of the environmental safety of their homes is still rather weak, and the lack of demand has left the “aldehyde-free wood-based panel technology” in the stage of exploration and the number of related patent applications is also very small.

(2) Technology growth (2001 to date): In 2001, the AQSIQ issued the first national mandatory standard for “the formaldehyde release limit of interior decoration”. Since then, the “aldehyde-free wood-based panel” technology has been developed. The laboratory of the scientific research unit truly enters the horizon of the people. However, due to weak basic research, until 2006, the research and development of urea-formaldehyde resin curing technology, formaldehyde scavenger, and soybean protein-based adhesive really got the attention of the market.

2. Applicant Analysis

Through the analysis of “standard applicants”, it is not difficult to find that the production technology of aldehyde-free wood-based panels is mainly concentrated in universities, research institutes, and plate production companies.

Among them, Nanjing Forestry University topped the list with 48 patent applications, followed by the Chinese Academy of Forestry and Anhui Baiyi Furniture.

The patents applied by Nanjing Forestry University were mainly based on the research of non-adhesives, modified adhesives, formaldehyde scavengers, wood reorganization technology and flame-retardant functions, among which “modified adhesives” were the most studied; the Chinese Academy of Forestry Research studied formaldehyde scavenging, Plastic film, new production process technology improvements, soybean protein adhesives are the main focus, and the focus is on the improvement of new production processes;

Based on the above analysis, there is a lot of research in the industry, such as the improvement of non-adhesive production processes and the removal of formaldehyde. In order to verify this inference, we need to analyze in depth the technical efficacy of the aldehyde-free wood-based panel production process.

3. Analysis of production process of aldehyde-free wood-based panels

At present, there are many technologies for producing aldehyde-free wood-based panels. The common ones are: the use of formaldehyde-free adhesives, the use of formaldehyde scavengers, and the improvement of the production process with little or no addition of glue. Each has its own advantages and disadvantages. After the analysis and summary of the Fangxiang Academy, a bubble diagram of different aldehyde-free wood-based panel production process (Figure 7) and the performance performance diagram of different aldehyde-free wood-based panels were formed.

The analysis found that a large number of patents mainly focused on the mixing, drying and hot pressing technologies of fiberboards, particleboards, plywood, and composite boards, with special emphasis on the research and development of fireproof, waterproof, and thermal insulation properties. However, in the production process of aldehyde-free wood-based panels, the main source of formaldehyde is in the sizing phase, and there are few studies on sizing. The industry generally believes that it is difficult to develop aldehyde-free adhesives and it is difficult to break through the limiting factors. For example, MDI (diphenylmethane diisocyanate) (MDI), which is widely used in production at present, does not produce formaldehyde, but it easily generates a great adhesion with metal. In order to avoid sticking to the pad and the hot platen, The layers of wood shavings are usually glued or used as special mold release agents, and the price of MDI is relatively high. In 2017, the average price of imported pure MDI in China was 2,852.63 US dollars per ton, which was 4 to 5 times that of ordinary urea formaldehyde resin.

In addition, there is more research on soy-based protein glue in aldehyde-free adhesives, which is also the earliest commercially available adhesive without aldehyde. As a bio-based aldehyde-free adhesive, soy protein gum uses soybean powder, soybean meal, soy protein isolate, etc. as raw materials, and water as a dispersion medium, adding an adhesive made of other additives, but it still exists in the process of separating soybean protein. The problem of environmental pollution.

According to relevant foreign data shows that chemically modified soybean gum, whether it is resistant to boiling water glue, or resistance to cold water bonding strength, both to meet the national standard adhesive strength requirements of the adhesive. However, though the phenolic modification can greatly improve the water-resistant adhesive strength of the soy-based adhesive, the phenolic product is relatively toxic and still poses a safety risk to human health. In recent years, many domestic companies have claimed that their products use “zero-formaldehyde” bio-adhesives of soybean gum, but the results of investigations by relevant regulatory authorities are not.

Taking wood flooring as an example, the associations of consumers in 28 provinces and cities including Beijing, Tianjin, and Hebei have been associated with the China Green House Environmental Technology Working Committee of the China Interior Decoration Association, according to the national standard GB18580-2001 “Interior Decoration Materials”. Formaldehyde emission limits for wood-based panels and their products. Environmental performance comparison tests were conducted on 35 mainstream brand samples collected on the market. The results showed that the formaldehyde release rate of the 35 samples was 97.14%, but none of the floors contained formaldehyde.

Although from a theoretical and technical point of view, biological glue can be achieved without formaldehyde at all. However, different companies have different R&D capabilities. Some companies are actually doing research, and more may be confused to increase publicity. The concept deceives consumers. Fang Chongrong, director of Zhejiang Provincial Forest Products Quality Inspection Station, said that formaldehyde is a material that increases the viscosity and adhesion of glue. Under the current technical conditions, the technical indexes of the density and water absorption expansion rate of the composite floor require the use of formaldehyde to ensure the quality stability. The use of aldehyde-free adhesive floor products is more costly first, and secondarily after leaving formaldehyde, the overall performance of the floor is difficult to stabilize and may not be able to meet the national standards for wood-based panels. Further in-depth analysis of the development of plywood, fiberboard and particle board three different wood-based panels:

4. Patent Application Trends and Technology Life Cycles of China’s No Aldehyde “Three Boards”

Since it takes a certain amount of time from the filing of a patent application to the disclosure, data in recent years can only serve as a reference. Looking at the trend of the number of applications, the overall trend of the “three-board” patent application is on the rise.

The three technical life cycle charts show that the overall trend is technology long-term. Although the development process is different, the technology life cycle of the production process patents is similar to that of the wood-based panels, so it will not be repeated here.

It is not difficult to see from the trend chart of the number of applications for related patents that the new technology for sheet metal production has grown explosively, which is inseparable from the high demands of the market, especially consumers, on the environmental performance of sheets.

The demand of the market and the attention of consumers have greatly promoted the research and development speed of related technologies, improved the ratio of urea-formaldehyde rubber, and developed new types of non-aldehyde adhesives, but due to factors such as material properties, process level, and production costs, etc. At present, there is no adhesive technology that can simultaneously meet the needs of large-scale production, process maturity, and low-cost industrialization.

There is a shortage of timber resources. How far is the alternative raw material from us?

While exploring the production process of “aldehyde-free wood-based panels”, China’s wood-based panel manufacturers also have to face the problem of shortage of raw materials.

Although the wood-based panel industry is conducive to saving timber resources, it eases the contradiction between China’s supply and demand for wood. With the rapid development of the building decoration and furniture industry, the domestic demand for wood is still growing rapidly, and the gap in timber supply is becoming increasingly prominent. In particular, policies have been introduced at home and abroad to strictly limit deforestation and export restrictions. This is a tantamount to artificial weaning and breaking the rice bowl.

At present, China’s wood-based panel companies must not only face the technical bottleneck of breaking the “aldehyde-free wood-based panel”, but also must find suitable wood alternatives as soon as possible. These seemingly unbreakable crises allow companies that are good at thinking and brave to innovate to see opportunities.

In the face of increasingly stringent wood cutting and export restriction policies at home and abroad, domestic wood-based panel companies urgently need to find alternative raw materials for wood. Our country is vast in size and rich in natural resources. In fact, the raw material that can perfectly replace wood is around us. It is a small bamboo.

However, although China’s bamboo production is rich, but in the face of huge market demand, only a small bamboo can handle it?

In addition, the bamboo charcoal, a derivative of bamboo, is widely used in many aspects such as purifying air, eliminating odor, absorbing moisture and mildew, inhibiting bacteria and repelling insects with its strong adsorption ability. Then, in the face of increasingly stringent challenges to the market’s demand for “aldehyde-free”, can the bamboo derivative be able to stand alone?

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