KR840001112B1 - Solid reactive catalyst for amino resins - Google Patents

Abstract

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Description

Solid Reactive Catalyst Composition for Amino Resin

The present invention relates to a solid reaction catalyst for amino resins composed of a mixture of organic and inorganic components. If this catalyst is added to an amino resin for wood fiber adhesion, a smaller amount of solid resin can increase the production rate without reducing the binding force.

The solid catalyst of the present invention contains organic and inorganic components. The organic component contains a solid, water-soluble aldehyde polymer and urea or melamine at room temperature, and the inorganic component is an alkali metal halide.

A method of converting a portion of the resin used to bond the fiber particles (but less than 50%) to a halide salt has already been proposed, for example in the case of particleboard production. However, the production rate cannot be increased in this way, and when a large amount of halide salt is used, the production rate is rather reduced due to the large amount of water used, in which case instead of using the usual methods used for particle board production This is because fibrin particles are separately sprayed with an aqueous solution of a halide salt, dried, and finally sprayed with an amino resin solution.

In addition, a method of using a high concentration aqueous solution of a mixture of organic and inorganic components as a catalyst has been proposed. The organic component contains a water-soluble condensate of formaldehyde and urea or urea and formaldehyde, and the inorganic component contains a water-soluble alkali metal halide. do.

In the polycondensation of amino resins for adhesion of fibrillar particles, if this catalyst solution is used together with a known catalyst, the polycondensation rate of the resin can be increased and at the same time, the amount of the solid resin can be reduced without decreasing the binding force. However, since the conventional catalyst is an aqueous solution, it is only stable for about two months at about 20 ° C. Therefore, it is not suitable for use in hot climates or when traveling over long distances.

The solid catalyst of the present invention, if its ingredients are firmly and reliably packed, its stability is substantially unlimited, surprisingly likewise increasing the polycondensation rate of the amino resin and at the same time reducing the amount of solid resin without reducing the binding force. Due to its solid and high solids content, the catalysts have high stability, making it easy to transport long distances at low cost, without any restrictions on climatic conditions or geographic location.

The solid reactive catalyst of the present invention has another advantage. Because of reduced resin usage and improved performance, the amount of free aldehydes in finished products such as mills and particle boards has been significantly reduced, and the plates produced are almost odorless.

By using the solid catalyst of the present invention, the curing rate of the resin at a high temperature was increased to a level that was not possible using only a known acid-curing catalyst. The addition of known acid curing catalysts increases the rate of cure, but above a certain level, further increases in the rate of cure degrade the properties of the bound fibrous material produced.

In addition, when known acid-curing catalysts are added to high levels, polycondensation occurs even at room temperature (in spite of the addition of inhibitors such as ammonia or hexamethylene tetramin). This shortens the shelf life of the adhesive at room temperature and causes foreground in the press prior to the introduction of the mat, which is a well known drawback.

However, using the catalyst of the present invention, the curing speed can be further increased, and consequently, the compression time can be shortened without causing any deterioration of the properties of the binder. However, the catalyst of the present invention that is added reacts only at high temperatures. Therefore, the polycondensation rate of the resin is significantly increased at the temperature of the compactor without any increase at room temperature, thereby avoiding the problem of foreground. The catalyst is combined with the resin itself to form a part thereof.

The combination of organic and inorganic constituents in the present catalyst exhibits a cooperative action. When only one of the components is added to the resin, the curing rate may be increased, but when combined, the increase is much greater than the sum of the two components. Moreover, the catalyst of the present invention significantly reduces the amount of resin used as the binder as compared to adding each component separately. The maximum possible reduction in the amount of solids is about 50%. What is necessary is just to use 50% of normal resin amount, and to add the catalyst of this invention to 25-50% with respect to normal resin amount. These percentages calculate all products as 100% solids by weight.

Examples of aldehyde polymers that are solid at room temperature and can be used in the present solid catalysts are the trimers of acetaldehyde known as paraaldehyde or 2,4,6-trimethyl-1,3,5-trioxane and acetaldehyde known as metaaldehyde There is a tetramer of, a trimer of formaldehyde known as trioxymethylene, a tetramer of formaldehyde known as tetraoxymethylene, and a mixture of formaldehyde polymers known as paraformaldehyde.

Examples of alkali halides used in the solid catalyst of the present invention include potassium chloride and lithium chloride, and preferred alkali halides are sodium chloride.

The solids content of this solid catalyst is 75 to 100% and depends on the amount of impurities and moisture contained in the starting materials used.

The fibrous material can be adhered to the wood fiber material by spraying a mixture of an amino resin, a conventional catalyst and the solid catalyst of the present invention, and curing the resin according to known methods at elevated temperatures and pressures. The catalyst can be used in all types of products using amino resins to bond wood fiber materials, including the production of particleboards using flat plate presses, continuous presses or calenders such as veneers such as wood grain or plywood, Or wood boards for the production of blackboards.

The following examples illustrate the invention and are not intended to be limiting, where% is by weight.

Example 1

This example illustrates the advantages of producing a particleboard by adding the solid catalyst according to the invention to the adhesive in the amounts given in the following table. It also shows the characteristics of the particleboard product.

[table]

Linear technology

Composition A is a urea formaldehyde adhesive, a conventional adhesive mixture made from traditional catalyst (ammonium chloride) as a curing agent, paraffin and water. Ammonia is usually added in all cases, and the pH of the composition is not critical.

The composition is sprayed onto the wood chips sufficient to bring the dry adhesive amount to 9% based on the wood chips.

Composition B contains 2250 g of a resin solution which is 75% of the amount of resin used in composition A. The remaining 750 g of resin solution (which contains 487.5 g of resin) is replaced by 297 g of a solid mixture of paraformaldehyde, urea and sodium chloride, which constitute the solid catalyst of the present invention. The ratio of resin solids replaced to solid catalysts is therefore 1.64: 1. The amount of hardener, which is a conventional catalyst, was also reduced to 215 g, which is 75% of the amount used in Composition A, because the catalyst of the present invention served as an adhesive and a hardener. In addition, the total weight of composition B reaches 94% of composition A, thus the spray amount of composition B is correspondingly reduced.

Composition C contains 2100 g of a resin solution which is 70% of the amount of resin used in composition A. The remaining 900g of resin solution (which contains 585g of solid resin) is replaced by 371g of the solid catalyst of the present invention. Thus, the ratio of replaced resin solids and solid resins is 1.57: 1. The amount of conventional catalyst is reduced to 205 g, which is about 70% compared to that of Composition A. Since the total weight of the composition C is 94.4% of the composition A, a smaller amount of the composition C is sprayed to obtain a sufficient adhesive saving effect.

Using the adhesive compositions A, B, and C, respectively, a particle board was produced according to the BISON system under the conditions kept constant at the following values.

As can be seen from the table, the three particleboards produced do not show much difference. However, when using Compositions B and C, the gel time was shorter than in the case of Composition A of the prior art which contained significantly more hardener.

Example 2

This example illustrates the use of melamine formaldehyde for the production of particleboard using the catalyst of the present invention.

The components used for the adhesive composition are as follows.

Two kinds of plates are prepared, one using composition 1 containing no catalyst of the present invention, and the other using composition 2 containing catalyst of the present invention.

The total amount of composition (1,5910 g of composition and 2,5352 g of composition) is sprayed onto 25 kg of homogeneous pieces, respectively.

The thickness of the plate produced was 17.5 mm, the press temperature was 200 ° C. and the pressure was 35 kg / cm ² .

The compression time is 10 seconds / mm. The manufactured plate has the following characteristics.

It can be seen from the above table that the two plates are equivalent.

Example 3

This example illustrates the use of the catalyst of the present invention in the production of particleboard, which has a higher inorganic content than the catalyst used in the previous examples.

The components used in the adhesive composition are as follows.

(i) The catalyst solution according to the present invention has the following composition.

Two types of plates are prepared, one using composition 1 without the catalyst of the invention and the other using composition 2 with the catalyst of the invention.

Each of these compositions is sprayed onto 25 kg of homogeneous wood chips. The gel time of composition 1 is 75 seconds and the gel time of composition 2 is 70 seconds.

The plate is manufactured under the following conditions.

The manufactured plate has the following characteristics.

It can be seen from the above results that the two types of plates are equal in quality and that the plates made at 8 seconds / mm are slightly better than the plates made with Composition 2.

Claims (1)

Sodium chloride and an organic component consisting of an aldehyde polymer and urea and / or melamine selected from trimers of acetaldehyde, tetramers of acetaldehyde, tetramers of formaldehyde, tetramers of formaldehyde and paraformaldehyde, which are solid and water-soluble at room temperature A solid reactive catalyst composition for polycondensation of amino resins used to bind wood cellulose, characterized in that consisting of inorganic metal constituents selected from the group consisting of potassium chloride and lithium chloride.