When it comes to the formaldehyde problem of furniture boards, many friends will say, buy solid wood.
In fact, the average person is unlikely to avoid wood-based panels in their homes. On the one hand, it is because the cost of using solid wood in the whole house is too high, and the other is because the properties of solid wood are not necessarily suitable for all occasions, such as cabinets, balcony cabinets, bathroom cabinets, such as dining tables and coffee tables that need wear resistance and corrosion resistance.
If it is inevitable to use wood-based panels, how to choose wood-based panels? It must be environmentally friendly.
The international indoor air quality standard stipulates that the indoor formaldehyde safety value should be lower than 0.1mg/m3. And the test proves that in a standard enclosed space of 20 cubic meters, the temperature is 25 ℃ and the humidity is 65% (equivalent to an air-conditioned indoor environment):
Using 10 sheets of E1 grade board, the cumulative concentration of formaldehyde in the air can reach 0.5mg/m3 after 1.6 hours, and using 10 sheets of E0 grade board, the cumulative concentration of formaldehyde in the air can reach 0.5mg/m3 after 2 hours.
Under normal circumstances, in a 30-square-meter living space, the total usage of E1 grade boards shall not exceed 14 sheets, and the total usage of E0 grade boards shall not exceed 17 sheets, otherwise the cumulative concentration of indoor formaldehyde is likely to exceed the safety level. value.
Under these conditions, in general, it is common to use the main environmental protection E0 grade board, and it is common to use 15 boards for 30 square meters. If you add 30 square floors, that is, 10 boards, you can make some siding if possible. Yes, this does not include walls, ceilings, and the accumulated formaldehyde has already exceeded the standard.
This is why there are so many formaldehyde treatment units and all kinds of ineffective formaldehyde removal products flying all over the sky.
OK, back to the topic.
So when it comes to the manufacture of aldehyde-free man-made veneers, I think there are actually three key parts, one is the aldehyde-free substrate, the second is the aldehyde-free veneer, and the third is the aldehyde-free process.
I would like to point out the formaldehyde-free mentioned here. Formaldehyde-free does not mean that this sheet does not contain formaldehyde, because most of the things in the world contain formaldehyde. Vegetables, fruits, cigarettes, human bodies, etc., all contain trace amounts. Formaldehyde, what we are talking about is that artificial formaldehyde is no longer added as a binder in the artificial board manufacturing process. The formaldehyde content we pursue for the final detection of artificial boards is actually almost the same as that of solid wood, so that the indoor formaldehyde released by the products produced by the board is released. The amount is very small, and the inspection report will be verified later.
In this way, there will be no E0, E1 standards. In other words, in a sense, it is not a question of how low the formaldehyde emission is, but a question of yes and no, that is, we will fundamentally solve it in the plate. The presence.
Let’s talk about the selection and process of aldehyde-free substrates
For the manufacture of aldehyde-free substrates, in recent years, there have been relatively mature solutions in the industry. We have summarized three types:
One is to use MDI adhesive to make OSB substrate
The second is to use polyethylene film to make plywood substrates
The third is to use biomass adhesives to manufacture blockboard substrates
Combining our actual situation, first of all, we confirmed the process of ecological board, not other wood-based boards, such as multi-layer board, particle board, MDF, etc. This is the basis, because the amount of glue applied in the ecological board process is relatively minimal, even if it is used Very expensive glue can also take advantage of the coating amount. The process of ecological board substrate is the process of blockboard.
Then talk about the adhesive part
The research and development of aldehyde-free glue by rubber factories has long been eager for foreign countries such as Tier, Bayer, Huntsman, Henkel, Crepo, German Rubber King, Japan Sika, etc. Domestic Wanhua MDI, Ningbo Eight Yiji and Zhengzhou Chensheng’s soybean glue and Shandong Dongying modified polyurethane have been recommended by the Forestry Association for many times. Our laboratory has participated in the experimental test, but the effect was not good at that time, mainly because the formaldehyde was not available, and the bonding strength was always low. , Open glue all day long, the second-class board standard has been difficult to pass.
During this time, we still used Wanhua’s MDI and Finnish Tyre’s phenolic glue. The main component of MDI is isocyanate, which requires high production requirements, the process is highly toxic, and the price is not cheap. In addition, we also At that time, I was always worried about the release of C6H6. Tyre phenolic, the formaldehyde content is 20%, in addition, we are also worried about the problem of free phenol, but these two adhesives are very stable in use. Urea-formaldehyde, Kang-aldehyde or something is still much stronger.
Next, let’s talk about our pursuit of a formaldehyde-free finish.
At that time, even now all the eco-boards on the market were all melamine veneer paper, which were all aldehydes added. At present, even the international IP paper industry has not overcome the aldehyde-free problem of melamine-finished stained paper, so these sheets cannot even be added without aldehyde, and it is no problem to say that E0E1.
At that time, schattdecor in Germany and Mead in the United States had technical expertise in research and development. We proposed the products we needed, but due to technological limitations, after all, the laminate flooring market, the fireproof board market and the melamine decorative panel market made them too busy. In the end, we gave up paper, Turn to plastic film materials. Now think about what we have set for ourselves. The paper transfer film seems to be simple and nothing, but the actual later process has completely changed, because the later process of the paper transfer film is from the sheet lamination process to the coil lamination process. , We all know that the coil is not as good as the sheet!
In fact, the process of aldehyde-free veneer is very similar to the process of core board research and development. Formaldehyde-free veneer has long been available. The polypropylene printing film developed by DNP and TOPPAN in Japan, also known as PP, is very realistic. The wood grain texture is very good, and it is very environmentally friendly, but the price is super expensive, and the flatness of the substrate board is very high.