Formaldehyde scavenger for urea-formaldehyde glue and technique for producing the same

Abstract

The invention relates to formaldehyde scavenger which belongs to novel aldehyde remover used in urea-formaldehyde glue; the formaldehyde scavenger essentially solves the problems that the urea-formaldehyde glue adhesive materials reduce the release of formaldehyde during the production and use processes, which belongs to the aldehyde reducing technology during the urea-formaldehyde glue use process; the formaldehyde scavenger is characterized by comprising compositive polyphosphate, monadic organic amine, binary organic amine, phenolic compounds, lignin-containing compounds, hydrazine compounds, urea and products thereof produced by the reaction with acid, sulfite and the like, being added with water according to the weight ratio of the materials. The synthesis and composite technology of the formaldehyde scavenger is a special method to prepare formaldehyde scavenger for man-made board. The formaldehyde scavenger has the advantages of easy and even mixture with glue, good aldehyde removing effectiveness without changing the plate, no impact on the strength and other physical and chemical properties of the plate when being added simultaneously with a curing agent when adjusting the glue, convenient use, storage and transportation, cheap price and the like, and is a novel aldehyde remover of environmental protection, high efficiency and excellent aldehyde removing performance.

Description

technical field [0001] The formaldehyde scavenger for urea-formaldehyde glue and its production process mainly solve the problem of reducing the release of formaldehyde during the hot pressing process of materials bonded by urea-formaldehyde glue, and belong to the formaldehyde-reducing technology in the use of urea-formaldehyde glue. Background technique [0002] Urea-formaldehyde glue is the most important glue for plywood such as particleboard, density board, and fiberboard, but the board produced by this type of glue has the disadvantage of releasing formaldehyde. Since the 1980s, many foreign countries have imposed strict formaldehyde emission restrictions on plywood production. my country also promulgated 10 mandatory national standards for interior decoration materials and building materials in 2002. All board manufacturers have to adopt Various measures are used to achieve this goal. Such as improving the production process of glue, adding formaldehyde scavenger, pos...

AI Technical Summary

Problems solved by technology

From the rubber-making process itself, whether it is an alkali-acid-alkali process or an acid-base process, whether it is to generate Urocycline or to generate mono-hydroxytotetrahydroxymethylurea, some of the chemical bonds will generate formaldehyde during the hot-pressing process, and a low molar ratio is used. Although glue-making can reduce the free formaldehyde in the glue, it can also reduce the amount of formaldehyde released in the board to a certain extent, but the glue is difficult to cure, and at the same time it will increase the water absorption expansion rate of the board, and the static bending strength and internal bonding strength of the board. Reduce, because to meet the product standard of plywood, the ratio of the amount of urea and aldehyde is generally above 1:1.05, and the molar ratio should not be too low.

[0003] Using post-processing methods, such as using ammonia gas to fumigate complex equipment, will cause environmental pollution and increase costs; spraying aldehyde remover on the pressed board and then hot pressing, although it can reduce the formaldehyde emission of the board to a certain extent , but reduce productivity, increase energy consumption, increase cost, repeat operations, increase labor, and greatly increase the cost of products

[0004] Through the surface coating process and spraying formaldehyde scavenger, the formaldehyde emission of the board can be reduced. After the scavenger is consumed or the film formed on the surface is incomplete, the release of formaldehyde cannot be prevented; the board with complete and tight film formation, Formaldehyde can be sealed in the board, but when there is a damaged place on the surface of the coating film, the formaldehyde will overflow from the damaged place, just like the surface of a balloon has holes, and the air will slowly overflow, while the furniture and boards will leak out during decoration. It is impossible for the membrane to be completely closed, so it is generally impossible to fundamentally eliminate formaldehyde by using the coating process, and the surface coating may bring new pollution of benzene compounds. And spraying formaldehyde scavenger may also make the surface coating Discoloration, bringing new pollution

[0005] During the hot pressing and curing process of the board, the decomposition of methylol urea, ether bond and part of the methylene bond and the oxidation of part of the methanol lead to the emission of formaldehyde in the board. This is because the scavenger for removing free formaldehyde in the glue cannot effectively act Due to the technical barriers caused by the mandatory standard for formaldehyde emission of wood-based panels and foreign technical standards in 2002, many panel manufacturers in China who lack the means of reducing formaldehyde are facing difficulties, and the export of domestic panels has been severely restricted. Therefore, domestic board manufacturers are in urgent need of effective means of reducing aldehydes and methods of removing aldehydes. Therefore, to fundamentally solve the problem of indoor formaldehyde release, we must solve the problem from the source of board production, that is, from the glue and hot pressing process of bonding boards. Most of the existing formaldehyde scavengers are based on eliminating free formaldehyde in the glue and adding active hydrogen to the glue as the direction of effort. Like CN92107276.7, a microcrystal containing magnesium and soaked in urea is used. Porous clay attapulgite is used as a free formaldehyde scavenger in the glue. CN93121414.9 adopts sulfanilic acid, urea, etc. to join in the urea glue to be used as a free formaldehyde catcher in the glue, which can reduce the free formaldehyde in the glue more, However, the plate after hot pressing still releases more formaldehyde

Some materials use hydrogen peroxide, persulfate, etc. to promote the oxidation of formaldehyde, but also oxidize the methanol in the glue. CN02138527.0 proposes to use hydrazide compound and penetrant as the post-treatment agent for the industrial production of wood-based panels. CN02113857.5 Adopt hydrazide, metal chloride, vitamin C, ferrous sulfate, penetrating agent etc. as the free formaldehyde trapping agent that releases in the newly-built house, CN01133329.4 adopts triethanolamine, EDTA, glucuronide etc. as the scavenging agent of indoor formaldehyde pollution and CN01140051.X is also used as a scavenger for indoor formaldehyde pollution. CN03100568.3 uses tea phenol as a formaldehyde absorption and conversion substance. These patents are for processing the formaldehyde produced after the production of wood-based panels, which are palliative means and have not solved the problem from the source. So far, no patent has been found to solve the release problem of formaldehyde in the production process of wood-based panels. The composition of the formaldehyde catcher sprayed on the surface of plywood in 1967 abroad: 4% ammonia (25%), 1.5% hydrazine hydrate (80% ), 1.5% casein and 90% water, it can only react with aldehydes under liquid and acidic conditions, and bring new pollution. It is powerless for subsequent formaldehyde release, and it provides more active hydrogen than urea to the glue. Substances that can react with aldehydes, such as hydrazine, aromatic amines, long-chain amines, urea, phenol, ammonia, inorganic ammonium salts, etc., adding such additives to urea-formaldehyde glue can effectively eliminate free aldehydes in the glue, but Although the amount of formaldehyde released in the board after hot pressing has been reduced, it still cannot meet the higher requirements of foreign indicators. The characteristic of the glue partner sold on the market is that it can remove free formaldehyde in the glue, which is very important for the hot pressing process. The removal ability of formaldehyde in the plywood is poor. Most of the domestic plywood manufacturers lack the corresponding means of reducing aldehydes and methods of removing aldehydes. The level of manufacturers is very small