CH665995A5 - METHOD FOR THE PRODUCTION OF FIRE-PROTECTED CHIPBOARDS AND WOODEN CHIPS. - Google Patents

Description

DESCRIPTION The invention relates to a method for producing fire-protected chipboard and wood chip molded parts.

The use of non-fire-resistant chipboard and chipboard parts in the construction sector is limited. Even the area of use of little fire-protected chipboard is still severely restricted, because here too the fire behavior is still insufficient. Attempts have therefore been made to further improve the fire behavior of the chipboard and the chipboard molded parts, but so far there have been steps in which a significantly improved resistance of the plates and moldings to the effects of flame had to be bought with a substantial loss of the technological properties.

Fire-protected wood chipboards are manufactured according to the previously known methods by pretreating the wood chips with fire protection agents. The wood chips are impregnated in an expensive and technically complex process without pressure or under pressure, and then dried to a moisture level required for the production of chipboard. Other methods generate the flame retardant in an upstream operation, e.g. through the use of boron minerals such as colemanite and inorganic acids. The chips are pretreated with this mixture, dried and used together with the resulting gypsum for the production of fire-protected boards. The wood chips, e.g. Fly ash or vermiculite added. It has also been proposed to use inorganic binders such as cement or water glass instead of the organic binders, in particular the glue resins. It has also been proposed to largely replace the wood chip content with inorganic fillers, which has led to considerable losses in strength, particularly in the outer layers. When using magnesite mixtures as binders (DE-PS 2 550 857) it was found that the plates had a clear hygroscopicity after pressing and after storage for several days. The further processing and finishing of such fire-protected chipboard is also problematic. Decorative direct coatings of such chipboard with e.g. melamine impregnated papers are not possible. Special tools are required for further processing and special suction devices must be installed, since such materials with inorganic binders such as e.g. Cement specifically produces relatively heavy dust.

To the extent that attempts have been made to mix the usual glue resins with fire retardants while largely maintaining the wood content, as mentioned at the beginning, this has so far only led to inadequate fire protection which still severely limits the field of application.

Furthermore, it is very problematic that the glue resins that are preferably used here tend to harden prematurely after the addition of common fire protection materials, in particular boric acid.

The present invention is therefore based on the object of demonstrating a method for producing fire-protected chipboard and chipboard molded parts, with which very good fire protection can be achieved in conjunction with the extensive preservation of the technological properties of the chipboard materials, so that these chipboard and chipboard moldings can be obtained as not Fire-protected panels and molded parts can be further processed and refined without any problems.

The solution according to the invention consists in that the glue resin is made highly acidic by the addition of fire protection materials and the pre-glued wood chips are mixed with the fillers preventing fire formation and then filled with these fillers.

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The binder-wood chip mixture is neutralized to the extent that the binder hardens in the usual way.

The method according to the invention contains several surprising effects. It has surprisingly been found that the addition of fire protection materials to the glue resin is less problematic if the mixture is very strongly acidic, e.g. in the order of magnitude of the pH value of about 2. In addition, this strongly acidic mixture has an extraordinarily high impregnation ability on the wood chips. In this way, part of the fire protection material can be easily introduced into the material. According to the invention, a further part of fire protection substances and substances preventing the formation of fire is now added to the already pre-glued wood chips by admixing these fillers, which in turn can be achieved in a problem-free and, in particular, also very homogeneous form, because the pre-gluing of the wood chips to do so leads to the fact that these fillers, which are usually supplied in powder form, do not separate again, particularly when scattered, which would not lead to a homogeneous end product. In contrast, segregation is impossible with this procedure. A highly fire-protected end product is thus obtained while largely maintaining the technological properties of a wood chip product, in conjunction with the strength values and the processing options that result in particular from the use of conventional glue resins for the production of chipboard. By adding the powdered fillers that prevent the formation of fire, the binder-wood chip mixture, which is initially strongly acidic from the binder mixture, can also be largely neutralized in the manner required for further processing. The costly pretreatment of the chips is no longer necessary. The production can be carried out with only minor changes to the chipboard plant. Despite the very good fire protection filler content, which automatically leads to a reduction in the wood chip content in the end product, it has surprisingly been found that this procedure practically only requires the same amount of binder as for an unprotected board, which is due to a certain extender effect of the salts and aggregates close.

Despite the proportion of filler in this procedure, the end products have a surprisingly high strength and, on the other hand, a very low smoke density during combustion.

Due to the possibility of being able to use the usual binders despite the excellent fire protection, not only are the technological properties of the non-fire-resistant chipboard practically completely retained, but some properties are also significantly improved, in particular the water absorption and thickness swell as well as the smoke development. In the case of plates produced by this process, the 2-hour swellings were approximately 2% and the 24-hour swellings 3-4%. The smoke densities were around 10%. Fire tests have also shown that there were still considerable residual strength values. After a fire test of 20 minutes at 700e C, the bending strength of the test specimens only decreased to about! / 3 the bending strength of the raw plate.

The boards produced by the process according to the invention with their high strength values, in particular of the outer layers, can then be finished without problems, such as non-fire-resistant chipboard, e.g. veneered or coated with resin-impregnated papers. The coated or veneered panels can be processed using the tool known for chipboard processing. Special extraction systems at the processing sites are not required for these fire-protected particle boards.

The boards produced by this process can be manufactured with the press factors and the usual press temperatures that are customary for chipboard. Both single-layer and multilayer chipboard, as well as corresponding molded parts, can be easily produced using this method. Further preferred embodiments of the method according to the invention are characterized in the dependent claims, which essentially relate to the use of certain selected fire retardants to be added to the glue resin and the use of certain selected fillers which prevent the formation of fire and the appropriate proportions of the various components.

As glue resin, i.e. melamine-formaldehyde condensation products, urea-formaldehyde condensation products or melamine-urea-phenol-formaldehyde condensation products or mixtures can be used as binders. Next are additions of up to 25% isocyanates such. B. Diphenylmethane-4,4'-diisocyanate possible. Hardeners are expediently added to the amine resins, for example an addition of 2-10% ammonium chloride, ammonium sulfate or diammonium peroxydisulfate in the form of a 10-30% aqueous solution. Phosphoric acid, boric acid and / or aluminum sulfate are expediently added as fire protection substances which lead to a strongly acidic setting of the glue-resin / fire protection substance mixture. For this very strongly acidic setting of the mixture, phosphoric acid is of particular importance.

The weight ratio of glue resin to phosphoric acid in particular can be varied within relatively wide limits and is in the range from 4: 1 to 1: 4, preferably 1: 2 to 2: 1.

The concentration of the glue resin batches and the fire protection materials is preferably adjusted so that with an initial moisture content of the chips of approx. 4%, a moisture content of approx. 10-25% of the glued chip mixture and fillers which prevent fire formation is achieved. As a result, the concentration of the glue batches in the solids content can vary from 55 to 80%.

As inorganic fillers that prevent the formation of fire, aluminum oxide hydrate, aluminum sulfate, dolomite, kaolin, diatomaceous earth and heavy spar as well as mixtures of these substances, each in a proportion by weight of 10 to 50%, have proven to be expedient.

A strong fire-protected chipboard manufactured according to this information consists of approximately one third each of wood chips, the binder-fire protection mixture and the inorganic fillers that prevent fire formation. Various exemplary embodiments of the raw material mixtures for the process according to the invention are specified in detail below.

Example 1:

1.2000 g of wood shavings with a thickness of 0.2 to 0.6 mm and a length of 1 - 15 mm are used with a residual moisture of 4 - 5%

390 g melamine resin (60%), molar ratio melamine: formaldehyde as 1: 2.0 8 g ammonium chloride (25% aqueous solution) 410 g phosphoric acid (60%) mixed.

Then a mixture of the pre-glued chips is made

500 g aluminum sulfate

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130 g boric acid

340 g of diatomaceous earth and

360 g of heavy spar added and mixed further.

The chip mixture is then sprinkled into a chip fleece and pressed in a deck press.

The plate obtained is sanded and then coated with decor papers impregnated with melamine resin.

Example 2:

1,200 g of wood shavings, thickness 0.2 - 0.6 mm, length 1 - 35 mm moisture: 4 - 5% with a mixture of 600 g melamine resin (60%), molar ratio

Melamine: formaldehyde 1: 1.6 60 g diammonium peroxidisulfate (10%) 400 g phosphoric acid (60%) and 130 g boric acid mixed.

Then 500 g of aluminum sulfate, 340 g of diatomaceous earth and 360 g of heavy spar are added

The chip mixture is sprinkled into a chip fleece and pressed in a deck press. After sanding, the wood chipboard is glued with a 60% melamine resin solution, covered with a wood veneer and pressed in a multi-level press. The chipboard veneered in this way is demolded while hot, the veneer is lightly sanded and then treated with a fire protection lacquer.

Example 3:

1,200 g wood chips, thickness 0.2 - 0.6 mm, length: 1 - 15 mm, moisture: 4-5% with 800 g melamine urea resin (60%), molar ratio melamine: urea 1: 1, molar ratio melamine / urine - Substance: formaldehyde 1: 1.4 400 g phosphoric acid (60%)

80 g boric acid mixed.

Subsequently, 500 g of diatomaceous earth and 700 g of heavy spar are added to the pre-glued chips and mixed further until an even distribution is achieved.

The chips are further processed as described in Example 1.

Example 4:

1,200 g wood chips, thickness: 0.2-0.6 mm, length: 1 - 15 mm. Humidity: 4 - 5%) with 400 g melamine resin. Molar ratio melamine: formaldehyde 1: 1.4. which as a hardener 50 g of ammonium sulfate. 30%, and 800 g of phosphoric acid (60%) was added. and 250 g of boric acid are mixed and then mixed with 250 g of aluminum oxide hydrate, 300 g of diatomaceous earth and 700 g of heavy spar and mixed further.

The chips treated in this way are further processed as described in Example 1.

Example 5:

1,200 g wood chips. Thickness: 0.4 - 0.8 mm. Length: 5 - 25 mm. Humidity: 4 - 5%. are with a mixture of 600 g melamine resin (60%) molar ratio melamine: formaldehyde 1: 1.6 150 g phosphoric acid (60%) and

200 g of boric acid treated.

A mixture of 400 g heavy spar 400 g kaolin 400 g kieselguhr is then added to the pre-glued chips and mixed further.

The chips are used for the middle layer.

Example 6:

1,200 g of wood shavings, thickness: 0.2 - 0.6 mm, length: 2 - 8 mm, moisture: approx. 5% with a mixture of 600 g melamine resin (60%), molar ratio

Melamine: formaldehyde like 1: 1.6 100 g boric acid

400 g phosphoric acid (60%) and 200 g aluminum sulfate glued and then mixed with 500 g kaolin and 500 g diatomaceous earth.

The chips are used for the top layer.

Example 7:

1,200 g of wood shavings, thickness: 0.2 - 0.6 mm, length: 2 - 8 mm, moisture: approx. 5% with a mixture of 400 g melamine resin (60%), molar ratio

Melamine: formaldehyde 1: 1.8 400 g phosphoric acid (60%)

Glued to 200 g of aluminum sulfate and then mixed further with 500 g of heavy spar 500 g of kaolin and 400 g of boric acid.

The treated wood chips are further processed as described in Example 1.

Example 8:

1,200 g wood shavings, thickness: 0.2 - 0.6 mm, length: 2-15 mm, moisture: 4 - 5% with 400 g melamine resin (60%), molar ratio

Melamine: formaldehyde such as 1: 1.8, 100 g phosphoric acid (60%) and 150 g boric acid mixed and then mixed further with 400 g heavy spar and 400 g aluminum oxide hydrate.

Processing is carried out as described in Example 1.

Example 9:

1,200 g wood chips, thickness: 0.2 - 0.6 mm, length: 1 - 15 mm, moisture: 4 - 5% with a mixture of 200 g melamine resin (60%), molar ratio

Melamine: formaldehyde treated as 1: 2.0 200 g phosphoric acid 200 g aluminum sulfate.

The pre-glued chip mixture is then mixed further with 120 g of boric acid, 120 g of diatomaceous earth, 40 g of kaolin and 45 g of dolomite.

The chips are processed further - as described in Example 1.

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Example 10:

1,200 g of wood shavings, thickness: 0.2 - 0.6 mm, moisture: 4 - 5%, length: 1 - 15 mm with 400 g melamine resin (60%), molar ratio

Melamine: formaldehyde as 1: 1.6 200 g boric acid 400 g phosphoric acid mixed and then a mixture of 400 g heavy spar 400 g aluminum sulfate 400 g dolomite added and mixed further.

The chips treated in this way are further processed, as described in Example 1.

Example 11:

1,200 g of wood shavings, thickness 0.2-0.6 mm, length: 1 - 15 mm, moisture: approx. 4% are made with a mixture of

400 g melamine urea formaldehyde resin 60 g diphenylmethane-4,4'-diisocyanate 460 g phosphoric acid (60%) 40 g diammonium peroxydisulfate (10%) and 640 g aluminum sulfate glued and then 450 g diatomaceous earth 150 g kaolin 150 g dicyanidamide and 450 g boric acid added and mixed to the end. The chips treated in this way are further processed as described in Example 1.

Example 12:

1,200 g wood shavings, thickness: 0.2 to 0.6 mm, length: 1 - 15 mm, moisture: 5% are mixed with 200 g diphenylmethane-4,4'-diisocyanate, 400 g phosphoric acid (60%)

400 g aluminum sulfate 200 g water mixed and then a mixture of

400 g of diatomaceous earth

150 g dolomite

100 g kaolin

400 g of boric acid added and mixed further.

The treated chips are processed as described in Example 1.

Example 13:

1,200 g of wood shavings, thickness: 0.2-0.6 mm, length: 1 - 15 mm, 4% moisture content

450 g melamine-urea-phenol-formaldehyde resin (60%) 200 g water 370 g boric acid and 15 g sodium hydroxide solution (50%)

mixed and then a mixture of 300 g aluminum sulfate 100 g kaolin 250 g diatomaceous earth 120 g dolomite is added and mixed further.

The chips treated in this way are further processed as described in Example 1.

All features disclosed in the documents, insofar as they are new compared to the prior art, are regarded as essential to the invention.

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Claims (12)

665 995 1. Process for the production of fire-protected chipboard and wood chip molded parts, by adding fire protection materials, mixing the wood chips with glue resin, scattering the pre-glued wood chips and pressing them, characterized in that the glue resin is strongly acidified by adding fire protection materials and the pre-glued wood chips are mixed with fillers before scattering, which likewise prevent the formation of fire and with which fillers the glue resin / wood chip mixture is at least largely neutralized. 2. The method according to claim 1, characterized in that the concentration of the glue resin batch and the fire protection materials is adjusted so that at an initial moisture content of the wood chips of approx. 4%, a moisture content of the pre-glued chip mixture and the fillers preventing the fire formation of approximately 10 - 25% results. 2nd PATENT CLAIMS 3. The method according to claim 1 or 2, characterized in that the glue resin is mixed with phosphoric acid. 4. The method according to claim 3, characterized in that the glue resin is mixed in a weight ratio of 4: 1 to 1: 4 phosphoric acid. 5. The method according to any one of claims 1 to 3, characterized in that boric acid is added to the glue batch. 6. The method according to claims 3 or 5, characterized in that the glue batch is mixed with aluminum sulfate. 7. The method according to any one of claims 1 to 6, characterized in that the glue resin is a hardener, e.g. 2-10% ammonium chloride or ammonium sulfate or diammonium peroxydisulfate is added in the form of a 10-30% aqueous solution. 8. The method according to claim 1, characterized in that the pre-glued wood chips as fire-preventing fillers inorganic substances, for example aluminum oxide hydrate, aluminum sulfate, dolomite, kaolin, diatomaceous earth, heavy spar or mixtures of these substances are mixed. 9. The method according to claim 8, characterized in that the fillers are preferably mixed in parts by weight between 10 and 50% - based on the plate weight. 10. The method according to claim 8, characterized in that the pre-glued wood chips together with the fillers also phosphoric acid and / or boric acid is supplied. 11. The method according to any one of claims 1 or 2, characterized in that urea, melamine, melamine-urea, melamine-urea-phenol-formaldehyde resins are used as glue resins, the amine resins also containing additives of up to 25% Isocyanates such as Diphenyl methane -4,4'-diisocyanate can contain or pure isocyanate is used as glue resin. 12. The method according to any one of claims 1 or 2, characterized in that the proportion of wood is between 20 and 85%, preferably 20-50%, depending on the fire protection equipment.