EP1699877A1

EP1699877A1 - Flame-retardant mixture for lignocellulose composites

Info

Publication number: EP1699877A1
Application number: EP04804337A
Authority: EP
Inventors: Manfred Rätzsch; Irmgard Bergmann; Uwe Müller; Michael Roth
Original assignee: AMI Agrolinz Melamine International GmbH
Current assignee: AMI Agrolinz Melamine International GmbH
Priority date: 2003-12-19
Filing date: 2004-12-17
Publication date: 2006-09-13
Also published as: RU2006121358A; RU2350636C2; WO2005061625A1; DE10361878A1; KR20060109949A; CN1898333A; US20070278463A1; NO20063333L; CA2549649A1

Abstract

The invention relates to a flame-retardant mixture for lignocellulose composites comprising 60 to 90 percent by weight of particulate and/or fibrous lignocellulose materials and 40 to 10 percent by weight of a flame retardant concentrate that is immobilized on and/or in the particulate and/or fibrous lignocellulose materials acting as carriers. Said flame retardant concentrate contains flame retardants of the boric acid type and/or the salts thereof, melamine resins, optional synergists, and other additives. The flame retardants are chemically coupled to the melamine resins while the flame retardant concentrates are immobilized on and/or in the carrier substance of the particulate and/or fibrous lignocellulose materials. The flame retardant mixture can be produced using a liquid impregnation method, a melt impregnation method, and a liquid impregnation-solid mixing method. Flame-resistant lignocellulose composites can be produced by melt-processing mixtures comprising 40 to 95 percent by weight of flame retardant and 60 to 5 percent by weight of duromer prepolymers, the duromers being hardened. As flame-resistant semifinished products and molding materials, the inventive lignocellulose composites provide great resistance against infestations by insects, fungi, and mold while the flame-retardant mixture is provided with great resistance against washing out. Preferably, said lignocellulose composites are suitable for exterior applications in the construction and leisure sector.

Description

Flame retardant mixture for lignocellulosic composites

The invention relates to a flame retardant mixture, in particular a flame retardant mixture for lignocellulosic composites, processes for their production, molding compositions for the production of flame retardant lignocellulosic composites and their use.

The use of boric acid and its salts (US 2002 011 593 A; GB 2 208 150 A1, WO 9913022 A1, US 6 306 317 A) and of melamine resins (PL 175 517 A) for flame retardant treatment of wood is known. The partial washability of the flame retardants in contact with water is a disadvantage.

It is also known to use formaldehyde resins such as urea-formaldehyde resins or melamine-formaldehyde resins in combination with glass fibers as carrier materials for flame retardant treatment of polyolefins such as polyethylene or ethylene-vinyl acetate copolymers (EP 0 219 024 A2) or polybutylene terephthalate (JP 2000 80 253 A ) to use. Flame retardant mixtures of phosphates and aminoplasts, which are applied to polypropylene fibers as a carrier material, are described in DE 23 14 996 A1. Are also known

Flame retardant materials made from aromatic polyamide fibers (EP 1 253 236 A1, US 4 162 275 A) or polyester fibers (DE 21 28 691 A1), which are impregnated with crosslinkable melamine resins. Layered silicates (JP 09 227 119 A, US 5 853 886 A), talc (CA 2 000 472 A) and clay (US 3 912 532 A) are also described as carrier materials for the fixation of melamine resins. However, these carrier-fixed melamine resins are unsuitable as flame retardants for lignocellulosic composites because of the limited compatibility of the carrier material with lignocellulosic substances.

It is the object of the present invention to provide a flame retardant mixture for lignocellulosic composites which has a high resistance to the ability to wash out the flame retardants when in contact with water and which provides reliable flame retardancy in lignocellulosic composites The object of the invention was achieved by a flame retardant mixture for lignocellulosic composites, the flame retardant mixture according to the invention comprising 60 to 90% by mass of particulate and / or fibrous lignocellulosic substances and 40 to 10% by mass of a flame retardant concentrate fixed to the particulate and / or fibrous lignocellulosic substances 16 to 60% by mass of flame retardants of the boric acid type and / or their salts, 16 to 75% by mass of melamine resins, and the flame retardants chemically coupled to the melamine resins, and the flame retardant concentrates on and / or in the carrier substance of the particulate and / or fibrous lignocellulosic ! Substances are fixed to the carrier.

Advantageously, the flame retardant concentrate fixed to the particulate and / or fibrous lignocellulosic substances, consisting of 16 to 60 mass% of flame retardants of the boric acid type and / or their salts and 16 to 75 mass% of melamine resins, additionally has up to 50 mass% of synergists and / or up to 0 to 25% by mass of other additives.

The term "carrier-fixed" is to be understood to mean that the final

Hardening of the melamine resins, the flame retardant concentrates are fixed on and / or in the lignocellulosic carrier substance.

The particulate and / or fibrous lignocellulosic substances contained in the flame retardant mixture are preferably chips, fibers and / or

Granulate particles from softwoods and / or hardwoods, regenerated cellulose fibers, paper fibers, cotton fibers and / or bast fibers from flax, hemp, jute, ramie, sisal or kenaf. The particulate lignocellulosic substances preferably have an average diameter of 0.05 to 2 mm. Fibrous lignocellulosic substances preferably have an average diameter of 0.02 to 2 mm and an average fiber length of 3 to 35 mm. Examples of the melamine resins contained in the flame retardant mixture are polycondensates of melamine or melamine derivatives and Ci-Cio-aldehydes with a molar ratio of melamine or melamine derivative / d-Cio-aldehyde 1: 1 to 1: 6 and their partial etherification products with CiC-IO alcohols, the melamine derivatives preferably ammeline, ammelide, acetoguanamine, Caprino- guanamine and / or butyroguanamine, and Cι-Cι ₀ -aldehydes preferably formaldehyde, acetaldehyde, trimethylolacetaldehyde, furfural, glyoxal and / or glutaraldehyde are. The melamine resins can also contain 0.1 to 10% by mass, based on the sum of melamine and melamine derivatives, of urea. 0

The melamine resins contained in the flame retardant mixture are preferably partially or completely etherified with C 1 -C ₈ onoalcohols, dialcohols and / or polyalcohols, polycondensates of melamine and CrC ₈ aldehydes, particularly preferably of melamine and formaldehyde. 5

The melamine resins are particularly preferably higher molecular weight melamine resin ethers with a number average molecular weight of 500 to 50,000.

The flame retardants of the type boric acids and / or their salts contained in the flame retardant mixture are preferably boric acid, metaboric acid,

Sodium tetraborate, sodium octaborate and / or ammonium pentaborate, the molar ratio B ₂ O ₃ : Na ₂ O being 1: 0 to 2: 1.

The synergists contained in the flame-retardant mixture are preferably 5 urea, melamine, melamine cyanurate, nichtveretherte melamine resin, partieii etherified melamine resin precondensates, cyanuric acid, and / or phosphorus salts of the type sodium phosphates, mono-ammonium phosphates and / or ammonium polyphosphates, wherein the proportion of the phosphorus salt, based on the ■ ^■ Total of synergists, is 0 to 60 mass%. To reduce the wash-out and better compatibility with the other ^ components, the phosphorus salts are preferably used encapsulated with melamine resin. The further additives contained in the flame retardant mixture are preferably hydrophobizing agents, impregnation aids and / or fixing aids for flame retardants.

Examples of hydrophobizing agents which can be contained in the flame retardant mixture are organic silicon compounds of the type organosilanols, organosiloxanes, organosilanes, organoaminosilanes, amino-terminated or hydroxyl-terminated polyorganosiloxanes; Surface fluorinated SiO ₂ nanoparticles, polytetrafluoroethylene nanoparticles and / or copolymers of ethylenically unsaturated C4-C20 dicarboxylic acid anhydrides containing imide groups.

Examples of impregnation aids that can be contained in the flame retardant mixture are methyl cellulose, oxyethyl cellulose and carboxymethyl cellulose.

Examples of fixing agents for flame retardants that can be included in the flame retardant blend ^', are methylolated melamine and methylolated acetoguanamine.

Flame retardant lignocellulosic composites, in particular flame retardant mixtures, can be produced according to the invention by a liquid impregnation process, a melt impregnation process and a liquid impregnation-solid mixing process.

In the liquid impregnation process for producing the flame retardant mixture for iignocellulosic composites, according to the invention, 60 to 90% by mass of particulate and / or fibrous lignocellulosic substances and 40 to 10% by mass of a flame retardant concentrate, composed of 16 to 60% by mass, fixed to the particulate and / or fibrous lignocellulosic substances Type boric acids and / or their salts, 16 to 75

% By mass of melamine resins, 0 to 50% by mass of synergists and 0 to 25% by mass of further additives, the flame retardants of the boric acid type and / or. the salts of which are chemically coupled to the melamine resins, and the flame retardant concentrates are present in a fixed manner on and / or in the carrier substance of the particulate and / or fibrous lignocellulosic substances, produced by the particulate and / or fibrous 5 lignocellulosic substances by spraying or dipping with solutions or

Dispersions of flame retardants of the boric acid type and / or their salts are impregnated at temperatures of 20 to 90 ° C, and the particulate and / or fibrous lignocellulosic substances impregnated with flame retardant concentrates are dried at 55 to 170 ° C with partial l o curing of the melamine resins.

The production is preferably carried out in that the particulate and / or fibrous lignocellulosic substances by spraying or dipping

15 - either with solutions of melamine resins in water, Ci-Cs alcohols or mixtures of 10 to 90 mass% water and 90 to 10 mass% Cι-C ₈ - alcohols with a solids content of melamine resins of 10 to 60 mass%, which the Contain flame retardants of the boric acid type and / or their salts and optionally synergists in dissolved or dispersed form,

20 - or with solutions or dispersions of the synergists, and subsequently with solutions of melamine resins in water, -C ₈ alcohols or mixtures of 10 to 90% by mass of water and 90 to 10 IVIasse% -C ₈ alcohols with a solids content Melamine resins of 10 to 60% by mass, which dissolved the flame retardants of the boric acid type and / or their salts

25 dispersed,

- Or with solutions or dispersions of the flame retardants of the boric acid type and / or their salts and the synergists and subsequently with solutions of melamine resins in water, -CC ₈ alcohols or mixtures of 10 to 90% by mass of water and 90 to 10% by mass of Cι -C ₈ alcohols with

30 a solids content of melamine resins of 10 to 60% by mass,

- or with solutions of melamine resins in water, Ci-Cs alcohols or mixtures of 10 to 90 mass% water and 90 to 10 mass% CC ₈ - Alcohols with a solids content of IVlamine resins of 10 to 60% by mass and subsequently with solutions of the flame retardants of the boric acid type and / or their salts, - or with solutions of the flame retardants of the boric acid type and / or their salts, subsequently with solutions or dispersions of the synergists, and subsequently with solutions of melamine resins in water, CrC ₈ alcohols or mixtures of 10 to 90 mass% water and 90 to 10 mass% Ci-Ca alcohols with a solids content of melamine resins of 10 to 60 mass%,

The further additives are added to the IVlamine resins, the flame retardants of the boric acid type and / or their salts and / or the synergists, and the impregnation steps take place with or without intermediate drying of the partially impregnated lignocellulosic substances.

In the melt impregnation process for producing the flame retardant mixture for lignocellulosic composites, according to the invention 60 to 90% by mass of particulate and / or fibrous lignocellulosic substances and 40 to 10% by mass of a flame retardant concentrate fixed to the particulate and / or fibrous lignocellulosic substances, consisting of 16 to 60% by mass Flame retardants of the boric acid type and / or their salts, 16 to 75% by mass of melamine resins, 0 to 50% by mass of synergists and 0 to 25% by mass of further additives, with flame retardants chemically coupled to the melamine resins, and the flame retardant concentrates on and / or in the carrier substance the particulate and / or fibrous lignocellulosic substances are fixed to the carrier, produced in that in melts of

Melamine resins at 35 to 130 ° C flame retardants of the boric acid type and / or their salts and optionally synergists are dispersed and partially dissolved and subsequently the particulate and / or fibrous lignocellulosic substances are dispersed and melt-impregnated in the mixtures, increasing the temperature to 90 to 170 ° C partial curing of the

Melamine resin takes place, and the other additives are the melamine resins Flame retardants of the boric acid type and / or their salts and / or the synergists are added.

In the liquid impregnation-solid mixing process for producing the flame retardant mixture for lignocellulosic composites, according to the invention, 60 to 90% by mass of particulate and / or fibrous lignocellulosic substances and 40 to 10% by mass of a flame retardant concentrate 60 fixed to the particulate and / or fibrous lignocellulosic substances consist of 16 % Flame retardants of the type boric acids and / or their salts, 16 to 75% by mass of melamine resins, 0 to 50% by mass of synergists and 0 to 25% by mass of further additives, the flame retardants being chemically coupled to the melamine resins, and the flame retardant concentrates to and / or present in the carrier substance of the particulate and / or fibrous lignocellulosic substances in a carrier-fixed manner, produced by the particulate and / or fibrous lignocellulosic substances by spraying or dipping with solutions or dispersions of flame retardants from the front T yp boric acids and / or their salts impregnated at temperatures of 20 to 90 ° C and the impregnated particulate and / or fibrous lignocellulosic substances are dried.

The particulate and / or fibrous lignocellulosic substances are preferred by spraying or dipping - either with solutions of melamine resins in water, C ₈ -C alcohols or mixtures of 10 to 90% by mass water and 90 to 10% by mass C 1 -C ₈ -

Aikohoien with a solids content of melamine resins of 10 to 60 mass% and simultaneously or subsequently impregnated with solutions of the flame retardants of the boric acid type and / or their salts at temperatures of 20 to 90 ° C, the impregnated particulate and / or fibrous lignocellulosic substances at 55 to 170 ° C with partial curing of the

Dried melamine resins and admixed synergists as solids with the impregnated particulate and / or fibrous lignocellulosic substances, - or impregnated with solutions of the flame retardants of the boric acid type and / or their salts at temperatures of 20 to 90 ° C, the impregnated particulate and / or fibrous lignocellulosic substances dried at 55 to 170 ° C, and the impregnated particulate and / or fibrous lignocellulosic Substances synergists and melamine resins as

Mixed solids,

- or impregnated with solutions and / or dispersions of the flame retardants of the boric acid type and / or their salts and synergists at temperatures of 20 to 90 ° C, the impregnated particulate and / or fibrous lignocellulosic substances dried at 55 to 170 ° C, and the impregnated Particulate and / or fibrous lignocellulosic substances mixed with melamine resins as a solid,

The further additives are added to the melamine resins, the flame retardants of the boric acid type and / or their salts and / or the synergists, and the impregnation steps are carried out with intermediate drying or without intermediate drying of the partially impregnated lignocellulosic substances.

The chemical coupling of the borate flame retardants to the melamine resins can be done during the production of the flame retardant mixture by ATR-IR

Track spectroscopy. With a sharp decrease in typical borate bands, melamine resin bands are shifted in the IR spectrum.

In the process variants for producing a flame retardant mixture for lignocellulosic composites, higher molecular weight melamine resin ethers with molar mass numbers of 500 to 50,000 are preferably used as melamine resins. Preference is given to higher molecular weight etherified melamine resin condensates which have been prepared by etherification of the hydroxymethylamino groups of the non-etherified melamine resin condensates by C 1 -C ₈ -alcohols and / or polyols of the type diols, triols and / or tetrols with molecular weights from 62 to 20,000. According to the invention are also molding compositions for the production of flame-retardant lignocellulosic composites, consisting of 40 to 95% by mass of the above-described flame retardant mixture, 60 to 5% by mass of duromer prepolymers of the phenol type, urea type, melamine type, guanidine type, cyanamide type and / or aniline type and 0.1 to 10% by mass of processing aids and / or auxiliaries, produced by dry premixing of the components and, if appropriate, subsequent melt compounding at 100 to 170 ° C. and granulation.

Examples of thermosetting prepolymers type phenol resins which can be contained in the molding compositions for producing the flame-retardant lignocellulosic composites, phenolic resins based on phenol, C _ϊ -Cg- alkylphenols, hydroxyphenols and / or bisphenols.

In addition to urea-formaldehyde resins, mixed condensates with phenols, acid amides or sulfonic acid amides are also examples of duromer prepolymers of the urea resin type which may be contained in the molding compositions for producing the flame-retardant lignocellulosic composites.

Examples of thermoset prepolymers of the melamine resin type which can be contained in the molding compositions for producing the flame-retardant lignocellulosic composites are condensates of melamine and C- _t- cio aldehydes with a molar ratio of melamine or melamine derivative / Ci-Cior aldehyde 1: 1 to 1: 6 and their partial etherification products with C 1 -C ₁₀ alcohols.

Examples of duromer prepolymers of the guanamine resin type which can be contained in the molding compositions for producing the flame-retardant lignocellulosic composites are resins which contain benzoguanamine, acetoguanamine, tetramethoxymethylbenzoguanamine, caprinoguanamine and / or butyroguanamine as guanamine component. Examples of duromer prepolymers of the aniline resin type which can be contained in the molding compositions for producing the flame-retardant lignocellulosic composites are aniline resins which, as aromatic diamines, can also contain toluidine and / or xylidines in addition to aniline.

Suitable processing aids that can be contained in the molding compositions are lubricants of the zinc stearate, calcium stearate and / or magnesium stearate type, non-stick agents of the talc type, aluminum oxide, sodium carbonate, calcium carbonate, silica and / or polytetrafluoroethylene polymer and / or thermoplastic polymers as flow improvers such as polycaprolactone or ethylene-vinyl acetate copolymer wax.

The molding compositions may contain pigments, UV absorbers and / or radical scavengers as auxiliary substances.

Examples of suitable pigments which can be contained in the molding compositions according to the invention are iron oxide, ester group-containing isoindoline pigments, anthracene fluorescent dyes, carbazole dioxazine and delta indanthrone blue pigment.

Examples of suitable UV absorbers which can be contained in the molding compositions according to the invention are 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) benzotriazole, 2,4-dihydroxybenzophenone and sodium 3- (2H-benzotriazol-2-yl) -5-sec-butyl-4-hydroxybenzenesulfate.

Examples of suitable radical scavengers which can be contained in the molding compositions according to the invention are bis- [2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl] ester sebacic acid, bis (2,2,6, 6-tetramethyl-4-piperidinyl) sebacate, N, N'- (2-hydroxyphenyl) ethanediamide and N, N - diformyl-N, N'-di- (1-oxyl radical-2,2,6,6-tetramethyl -4-piperidinyl) -1, 6-hexanediamine. Also according to the invention are flame-retardant lignocellulosic composites, produced by extrusion, injection molding or pressing of the above-described molding compositions at 100 to 220 ° C. with simultaneous curing.

The lignocellulosic composites can preferably be used as flame-retardant semi-finished products and molding materials with high resistance to insect attack, mold and mold attack and with high wash-out resistance of the flame retardant for outdoor use in the construction and leisure sectors.

The flame-retardant lignocellulosic composites according to the invention are flame-retardant. They decompose very slowly at high temperatures and emit little flammable and toxic gases. Without an external flame, they do not or hardly continue to burn on their own, the heat given off by the thermal

Decomposition is low, they glow and hardly glow. The flame retardant lignocellulosic composites can be classified as flame retardant (class B1) according to DIN 4102.

In the flame-retardant lignocellulosic composites according to the invention, the flame retardants have a high water resistance, since they are protected against washing out, only about 20% by mass of flame retardants which are not fixed to the carrier are slowly washed out. This provides permanent flame protection in a damp or wet environment.

The flameproofed iignoceiosic composites are highly protected against fungal and mold infestation due to the content of boron compounds. Because the boron compounds are protected against leaching, the lignocellulosic composites can be used in a damp or wet environment.

The invention is illustrated by the following examples: example 1

1.1 Production of the flame retardant mixture using the liquid impregnation process

840 g of spruce wood shavings (particle size 0.8 to 3 mm, residual moisture 5% by mass) are heated to 95 ° C in a high-speed mixer (capacity 10 l) at 500 rpm. 870 g of a solution of 40 g melamine, 15 g borax and 815 g water heated to 95 ° C. are sprayed onto the moving spruce wood particles through a nozzle within 20 minutes. The temperature is then raised to 120 ° C., dry air is blown in, and the impregnated spruce wood particles are dried to a residual moisture of 2.5% by mass within 90 minutes.

After cooling the spruce wood particles treated in the first impregnation step to 40 ° C, 280 g of a solution of 80 g of a methyl etherified melamine resin (average molar mass 700, molar ratio melamine / formaldehyde 1: 3, free OH groups) are not detectable on the spruce wood particles in the second impregnation step ), 60 g boric acid and 140 g methanol and water (volume ratio 2: 1) sprayed through a nozzle within 10 min. 0

The spruce wood particles impregnated with boric acid / borax as a flame retardant, melamine resin, and melamine as a synergist are dried at 60 ° C in a dry air stream with removal of water and methanol to a residual moisture of 2% by mass, with a partial hardening of the 5 etherified melamine resin ,

ATR / IR studies of the dry residue of the impregnation solutions show a chemical coupling of the boric acid to the methyl etherified melamine resin based on the decrease in typical BOH bands, shift in the BO bands and decrease in the NH bands in the methyl etherified melamine resin. 1.2 Production of the molding compounds and processing of the molding compounds into lignocellulosic composites

1050 g of the in 1.1. The flame retardant mixture produced is mixed with 250 g of a 5 granulated melamine resin prepolymer (with methanol and oligocaprolactone, average molecular weight 900, etherified melamine resin oligomer, average molecular weight 5000, molar ratio melamine / formaldehyde 1: 3, free OH groups undetectable, 10 mol% of the methylol groups etherified with oligocaprolactone), and 100 g processing aid (mixture of 92 g polycaprolactone, 0 mol mass 38000, and 8 g zinc stearate) mixed, compounded in a Brabender laboratory extruder at 115 ° C and granulated.

The molding compounds produced are pressed at 165 ° C / 50 bar to 15 mm and 30 mm composite panels 150 x 150 mm. 5

1.3 Testing the lignocellulosic composite

To test the fire behavior, test specimens milled out of the composite panel are tested. The test specimens do not continue to burn after 60 s o flame exposure to the test flame (self-extinguishing). The test specimens do not glow after removing the test flame. In contrast to composite test specimens, in which the spruce chips were not treated by impregnation, the charring is significantly slowed down. The lignocellulosic composite can be classified in B1 according to DIN 4102. 5

To test the washability of the flame retardant mixture, test specimens (15 x 15 x 15 mm) from the composite plate are stored in 1000 ml of water at 25 ° C. with moderate stirring to extract the boron compounds, samples are taken after 24 to 240 hours, and the boron content the extraction solution, o determined photometrically.

The extraction of the test specimens leads to the following results: Extraction time (hours) 24 48. 120 240

Washed-out amount of boron, based on 11.2 16.0 19.4 20.1 on the total content of the test specimen (mass%)

Around 20% by mass of the boron compounds are only weakly bound in the composite and are extracted from the composite during long extraction times, approx. 80% by mass of the boron compounds are stably bound in the composite in a carrier-fixed manner.

Example 2

Carrying out the experiment as in Example 1, but in the first impregnation step 870 g of a solution of 40 g melamine and 830 g water heated to 95 ° C. are sprayed through a nozzle within 20 minutes. In the second impregnation step, 280 g of a solution of 80 g of a methyl etherified melamine resin (average molar mass 1200, molar ratio melamine / formaldehyde 1: 3, free OH groups undetectable), 60 g boric acid and 140 g a mixture of methanol and water ( Volume ratio 2: 1) sprayed through a nozzle within 10 min.

The extraction of test specimens which were produced from the flame retardant mixture and granulated melamine resin prepolymer prepared in Example 2 leads to the following results:

Extraction time (hours) 24. 48 120 240

Washed-out amount of boron, based on 10.5 14.2 17.1 17.7 on the total content of the test specimen (mass%)

Example 3 Carrying out the experiment as in Example 1, but in the first impregnation step 180 g of a solution of 40 g of urea heated to 95 ° C. and 15 g of borax in 125 g of water are sprayed through a nozzle within 20 minutes. In the second impregnation step, 280 g of a solution of 80 g of a methyl etherified melamine resin (average molecular weight 1200, molar ratio melamine / formaldehyde 1: 3, free OH groups undetectable), 60 g boric acid and 140 g of a mixture of methanol and water ( Volume ratio 2: 1) sprayed through a nozzle within 10 min.

The extraction of test specimens which were produced from the flame retardant mixture and granulated melamine resin prepolymer prepared in Example 3 leads to the following results:

Extraction time (hours) 24 48 120 240

Washed-out amount of boron, based on 14.1 19.0 22.9 23.7 on the total content of the test specimen (mass%)

Example 4

Carrying out the experiment as in Example 1, but in the first impregnation step 140 g of a solution of 40 g urea in 100 g water heated to 95 ° C. are sprayed through a nozzle within 20 minutes. In the second impregnation step, 280 g of a solution of 80 g of a methyl etherified melamine resin (average moimass 1200, molar ratio melamine / formaldehyde 1: 3, free OH groups undetectable), 60 g boric acid and 140 g a mixture of methanol and water ( Volume ratio 2: 1) sprayed through a nozzle within 10 min. The extraction of test specimens which were produced from the flame retardant mixture and granulated melamine resin prepolymer prepared in Example 4 leads to the following results:

Extraction time (hours) 24 48, 120 240

Washed-out amount of boron, based on 12.7 17.6 21, 0 21, 8 on the total content of the test specimen (mass%)

Example 5

5.1 Preparation of the flame retardant mixture using the liquid impregnation / solid mixing method

60 g of boric acid in 280 g of a solution of 40 g of a methyl etherified melamine resin (average molecular weight 1500, molar ratio melamine / formaldehyde 1: 2.5, free OH groups undetectable), 40 g hexamethylmethylolmelamine and 200 g of a mixture of methanol and water (5: 2 by volume) dissolved with heating at 45 ° C. The solution is mixed in a high-speed mixer (capacity 10 l) at 55 ° C and 450 rpm on a moving mixture of 770 g pine wood chips (particle size 0.4 to 2.5 mm, residual moisture 10% by mass) and 143 g flax fibers (length 1 up to 15 mm, average diameter 0.07 mm, residual moisture 10 mass%) sprayed on.

30 g of melamine-encapsulated ammonium polyphosphate (average particle size 20 μm) are then metered into the mixer, the temperature is raised to 75 ° C., dry air is blown in, and the impregnated lignocellulose particles are dried to a residual moisture content of 2.0% by mass, with a partial hardening of the etherified melamine resin.

ATR / IR analyzes of the dry residue of the impregnation solution show, based on the decrease in typical BOH bands, shifting of the BO bands and decrease of the NH bands in the methyl etherified melamine resin a chemical coupling of the boric acid to the methyl etherified melamine resin.

5.2 Production of the molding compounds and processing of the molding compounds into 5 lignocellulosic composites

1075 g of the in 5.1. The flame retardant mixture prepared is mixed with 350 g of a granulated melamine resin prepolymer (with methanol and polyethylene glycol, average molecular weight 1000, etherified melamine resin oligomer, average molecular weight 0 5000, molar ratio of melamine / formaldehyde 1: 3.5, free OH groups undetectable, 18 mol% of Methylol groups are etherified with polyethylene glycol), and 75 g processing aid (mixture of 57 g polycaprolactone, molecular weight 38000, and 18 g polycaprolactone, molecular weight 2000) are mixed, compounded in a Brabender laboratory extruder at 110 ° C. and granulated. 5 The molding compounds produced are pressed at 165 ° C / 60 bar to 15 mm composite panels 150 x 150 mm.

5.3 Testing the lignocellulosic composite

o To check the washability of the flame retardant mixture

Test specimens (15 x 15 x 15 mm) from the composite plate were stored in 1000 ml of water at 25 ° C. with moderate stirring to extract the boron compounds, samples were taken after 24 to 240 hours, and the boron content of the extraction solution was determined photometrically. 5

The extraction of the test specimens leads to the following results:

Extraction time (hours) 24 48 120 240 0 Washed-out amount of boron, related to 10.8. 14.4 17.1 17.6 on the total content of the test specimen (mass%) Example 6

6.1 Production of the flame retardant mixture according to the liquid impregnation process

5

900 g of spruce wood shavings (particle size 0.8 to 3 mm, residual moisture 10 mass%) are heated in a high-speed mixer (capacity 10 1) at 700 rpm to 70 ° C. A solution of 45 g disodium octaborate, 30 g urea and 10 g boric acid in 160 g water at 70 ° C0 is sprayed onto the moving spruce wood particles. Immediately afterwards, 205 g of a solution of 90 g of a methyl etherified melamine resin heated to 70 ° C. (average molar mass 1200, molar ratio melamine / formaldehyde 1: 3, free OH groups not detectable) in 115 g of a mixture of methanol and water (Volume ratio 2: 1) sprayed on, and the impregnated spruce wood chips 5 dried at 110 ° C in a dry air stream with removal of water and methanol to a residual moisture of 2% by mass, whereby the etherified melamine resin is partially cured.

ATR / IR - Studies of the dry residue of the impregnation solutions show o a chemical coupling of the boric acid to the methyl-etherified melamine resin based on the decrease in typical B-O-H bands, shift in the B-O bands and decrease in the N-H bands in the methyl-etherified melamine resin.

6.2 Production of the molding compounds and processing of the molding compounds into 5 lignocellulosic composites

1090 g of the in 7.1. The flame retardant mixture produced is mixed with 320 g of a granulated melamine resin prepolymer (with methanol and polycapro-lactone, trifunctional, average molecular weight 2000, etherified melamine resin oligomer, average 0 molecular weight 6500, molar ratio melamine / formaldehyde 1: 3.5, free OH groups not detectable, 15 mol% of the methylol groups are with polycaprolactone etherified) mixed, compounded in a Brabender laboratory extruder at 110 ° C and granulated.

The molding materials produced are pressed at 170 ° C / 65 bar to 15 mm composite 5 plates 150 x 150 mm.

6.3 Testing the lignocellulosic composite

To test the washability of the flame retardant mixture, 10 test specimens (15 x 15 x 15 mm) from the composite panel in 1000 ml of water are added

Stored at 25 ° C with moderate stirring to extract the boron compounds, after

Samples are taken for 24 to 240 hours, and the boron content of the extraction solution is determined photometrically.

The extraction of the test specimens leads to the following results: 15 extraction time (hours) 24 48 120 240

Washed-out amount of boron, based on the total content of the test specimen (mass%) 14.2 18.5 22.8 23.7

Example 7

20

7.1 Production of the flame retardant mixture using the liquid impregnation / solid mixing method

60 g boric acid, 6 g borax decahydrate and 75 g methyl-etherified 25 melamine resin (average molar mass 1500, molar ratio melamine / formaldehyde 1:

2.5, free OH groups undetectable) are made in 250 g of a mixture

Methanol and water (volume ratio 1: 2) dissolved with heating at 60 ° C.

The solution is in a high-speed mixer (capacity 10 l) at 60 ° C and 600

Rpm to a moving mixture of 800 g pine wood shavings (particle size 0.4 30 to 2.5 mm, residual moisture 10 mass%) and 110 g hemp fibers (length 1.5 to 18 mm, average diameter 0.06 mm, residual moisture 10 Mass%) sprayed on within 15 min. 35 g of melamine cyanurate (average particle size 15 μm) are then metered into the mixer at 1200 rpm, the temperature is raised to 90 ° C., dry air is blown in, and the impregnated lignocellulose particles are dried to a residual moisture content of 5% by mass, one partial hardening of the etherified melamine resin takes place.

ATR / IR studies of the dry residue of the impregnation solution show a chemical coupling of the boric acid to the methyl etherified melamine resin based on the decrease in typical B-O-H bands, shift of the B-O bands and decrease in N-H bands in the methyl etherified melamine resin.

7.2 Production of the molding compounds and processing of the molding compounds into lignocellulosic composites 5

1085 g of the in 7.1. The flame retardant mixture prepared is mixed with 220 g of a granulated melamine resin prepolymer (melamine resin oligomer etherified with methanol and triethylene glycol, average molecular weight 3000, molar ratio melamine / formaldehyde 1: 3, free OH groups not detectable, 7 mol% of the o methylol groups are etherified with triethylene glycol ), and 75 g of processing aids (ethylene-vinyl acetate copolymer wax, molecular weight average 6500, vinyl acetate content 16% by mass) mixed, compounded in a Brabender laboratory extruder at 110 ° C and granulated. , ,

The molding compounds produced are pressed at 165 ° C / 60 bar to 15 mm composite 5 plates 150 x 150 mm.

7.3 Testing the lignocellulosic composite

To test the washability of the flame retardant mixture, o test specimens (15 x 15 x 15 mm) from the composite panel in 1000 ml of water are added

Stored at 25 ° C with moderate stirring to extract the boron compounds, after Samples are taken for 24 to 240 hours, and the boron content of the extraction solution is determined photometrically.

The extraction of the test specimens leads to the following results: Extraction time (hours) 24 48 120 240

Washed-out amount of boron, based on the total content of the test specimen (mass%) 12.8 17.8 21, 8 22.4

Example e

8.1 Production of the flame retardant mixture using the melt impregnation process

85 g of a granulated melamine resin prepolymer (melamine resin oligomer etherified with methanol and bis (hydroxyethyl) terephthalate, average molar mass 4500, molar ratio melamine / formaldehyde 1: 3.2, free OH groups) are placed in a Brabender kneader (capacity 500 ml) undetectable, 22 mol% of the methylol groups are etherified with bis (hydroxyethyl) terephthalate) melted at 85 ° C. and 25 g of boric acid, 12 g of borax and 6 g of melamine are metered into the melt and homogenized for 10 minutes with the melamine resin melt. 260 g of oak wood particles (average diameter 0.35 mm, residual moisture 1.0% by mass) are then metered into the melt and kneaded at 85 ° C. for 8 minutes to impregnate with the melt. By increasing the temperature to 105 ° C. and kneading for 4 minutes, the etherified part is partially cured

Melaminharzoligomers. The flame retardant mixture is discharged and, after solidification, ground in a granulator.

8.2 Production of the molding compounds and processing of the molding compounds into lignocellulosic composites 400 g of the in 8.1. The flame retardant mixture prepared is mixed with 100 g of a ground phenol novolak (average molar mass 720, molar ratio phenol / formaldehyde 1: 0.68) and 25 g polycaprolactone (molar mass 38000), compounded in a Brabender laboratory extruder at 120 ° C. and granulated. 5 The molding materials produced are pressed at 15 ° C / 50 bar to 15 mm composite sheets 150 x 150 mm.

8.3 Testing the lignocellulosic composite

l o To check the washability of the flame retardant mixture

Test specimens (15 x 15 x 15 mm) from the composite plate were stored in 1000 ml of water at 25 ° C. with moderate stirring to extract the boron compounds, samples were taken after 24 to 240 hours, and the boron content of the extraction solution was determined photometrically.

15 The extraction of the test specimens leads to the following results:

Extraction time (hours) 24 48 120 240

Washed-out amount of boron, based on the total content of

Test specimen (mass%) 12.8 15.9 21, 8 22.6

20

Claims

claims

5 1. Flame retardant mixture for lignocellulosic composites,

marked by,

-60 to 90% by mass of particulate and / or fibrous lignocellulosic substances and

-40 to 10% by mass of a flame retardant concentrate fixed on and / or in the particulate and / or fibrous lignocellulosic substances, with 5

16 to 60% by mass of flame retardants of the boric acid type and / or their salts, and

16 to 75% by mass of melamine resins,

o wherein the flame retardants of the boric acid type and / or their salts are chemically coupled to the melamine resins, and the flame retardant concentrates are present on and / or in the carrier substance of the particulate and / or fibrous lignocellulosic substances. 5

2. Flame retardant mixture according to claim 1, characterized in that the flame retardant concentrate fixed to and / or in the particulate and / or fibrous lignocellulosic substances further comprises up to 50% by mass of synergists and / or up to 25% by mass of further additives.

3. Flame retardant mixture according to claim 1 or 2, characterized in that the particulate and / or fibrous lignocellulosic substances Chips, fibers and / or granulate particles from softwood and / or hardwood, regenerated cellulose fibers, paper fibers, cotton fibers and / or bast fibers from flax, hemp, jute, ramie, sisal or kenaf.

\. Flame retardant mixture according to at least one of Claims 1 to 3,. characterized in that the melamine resins are partially or completely etherified with C 1 -C ₈ -monoalcohols, dialcohols and / or polyalcohols, polycondensates of melamine and C 1 -C ₈ -aldehydes, preferably of melamine and formaldehyde.

5. Flame retardant mixture according to at least one of the preceding claims, characterized in that the melamine resins are higher molecular weight melamine resin ethers with a number average molecular weight of 500 to 50,000.

6. Flame retardant mixture according to at least one of the preceding claims, characterized in that the flame retardants are of the boric acid and / or salt type, boric acid, metaboric acid, sodium tetraborate, sodium octaborate and / or ammonium pentaborate, the molar ratio being B ₂ O ₃ : Na ₂ O 1 : 0 to 2: 1.

7. Flame retardant mixture according to at least one of the preceding claims, characterized in that the synergists urea, melamine, melamine cyanurate, non-etherified melamine resin precondensates, partially etherified melamine resin precondensates, cyanuric acid and / or

Are phosphorus salts of the sodium phosphate, mono-ammonium phosphate and / or ammonium polyphosphate type, the proportion of the phosphorus salts, based on the total sum of the synergists, being 0 to 60% by mass.

8. Flame retardant mixture according to at least one of the preceding

Claims, characterized in that the further additives Hydrophobing agents, impregnation aids and / or fixing aids for flame retardants are.

9. A method for producing a flame-retardant lignocellulosic composite with a flame retardant mixture according to at least one of the

Claims 1 to 8,

characterized in that

the composite is produced by a liquid impregnation process in which the particulate and / or fibrous lignocellulosic substances are impregnated by spraying or dipping with solutions or dispersions of flame retardants of the boric acid type and / or their salts at temperatures of 20 to 90 ° C, and with Flame retardant concentrates impregnated particulate and / or fibrous lignocellulosic substances are dried at 55 to 170 ° C with partial curing of the melamine resins.

10. The method according to claim 9, characterized in that the particulate and / or fibrous lignocellulosic substances with

Solutions of melamine resins in water, -C ₈ alcohols or mixtures of 10 to 90 mass% water and 90 to 10 mass% C ^ Ca alcohols with a solids content of melamine resins of 10 to 60 mass%, which are the flame retardants of the boric acid type and / or their salts and optionally synergists, dissolved or dispersed; be impregnated.

11. The method according to claim 9, characterized in that the particulate and / or fibrous lignocellulosic substances with solutions or dispersions of the synergists, and subsequently with solutions of melamine resins in water, Ci-Cs alcohols or mixtures of 10 to 90 mass% water and 90 to 10 mass% -C ₈ alcohols with a Solids content of 10 to 60% by mass of melamine resins, which contain the flame retardants of the boric acid type and / or their salts in dissolved or dispersed form; be impregnated.

12. The method according to claim 9, characterized in that the particulate and / or fibrous lignocellulosic substances with solutions or dispersions of the flame retardants and the synergists and subsequently with solutions of melamine resins in water, CrC ₈ alcohols or mixtures of 10 to 90 mass% water and 90 to 10% by mass of Ci-C ₈ alcohols with a solids content of melamine resins of 10 to 60

Mass%, to be impregnated.

13. The method according to claim 9, characterized in that the particulate and / or fibrous lignocellulosic substances with solutions or dispersions of the flame retardants and the synergists and subsequently with solutions of melamine resins in water, -CC ₈ alcohols or mixtures of 10 to 90 mass % Water and 90 to 10 mass% Cr Ca alcohols with a solids content of melamine resins of 10 to 60 mass%; be impregnated.

14. The method according to claim 9, characterized in that the particulate and / or fibrous lignocellulosic substances with solutions of melamine resins in water, -CC ₈ alcohols or mixtures of 10 to 90 mass% water and 90 to 10 mass% CrCs alcohols with a solids content of melamine resins of 10 to 60% by mass and subsequently impregnated with solutions of the flame retardants of the boric acid type and / or their salts.

15. The method according to claim 9, characterized in that the particulate and / or fibrous lignocellulosic substances with

Solutions of the flame retardants of the boric acid type and / or their salts, subsequently with solutions or dispersions of the synergists, and subsequently impregnated with solutions of melamine resins in water, -C ₈ alcohols or mixtures of 10 to 90% by mass of water and 90 to 10% by mass of CC ₈ alcohols with a solids content of melamine resins of 10 to 60% by mass.

16. The method according to at least one of claims 9 to 15, characterized in that the further additives are added to the melamine resins, the flame retardants of the boric acid type and / or their salts and / or the synergists.

17. A method for producing a flame-retardant lignocellulosic composite with a flame retardant mixture as claimed in at least one of claims 1 to 8,

characterized in that

the flame retardant mixture is produced by a melt impregnation process in which flame retardants are dispersed and partially dissolved in melts of melamine resins at 35 to 130 ° C., and subsequently the particulate and / or fibrous lignocellulosic substances are dispersed and melt-impregnated in the mixtures,

whereby a partial curing of the melamine resin takes place by increasing the temperature to 90 to 170 ° C., and wherein the further additives

Melamine resins, the flame retardants of the boric acid type and / or their salts and / or the synergists are added.

18. The method according to claim 17, characterized in that in the

Melt impregnation process in the melts of melamine resins at 35 up to 130 ° C in addition to the flame retardants of the boric acid type and / or their salts and also synergists.

19. The method with a flame retardant mixture according to at least one of claims 1 to 8,

characterized in that

the composite is produced by a liquid impregnation-solid mixing process in which the particulate and / or fibrous lignocellulosic substances are impregnated by spraying or dipping with solutions or dispersions of flame retardants of the boric acid type and / or their salts at temperatures of 20 to 90 ° C. and impregnating them particulate and / or fibrous lignocellulosic substances are dried.

20. The method according to claim 19, characterized in that the particulate and / or fibrous lignocellulosic substances with solutions of melamine resins in water, -CC ₈ alcohols or mixtures of 10 to 90 mass% water and 90 to 10 mass% Cι-C ₈ -alcohols with a solids content of melamine resins of 10 to 60% by mass and simultaneously or subsequently impregnated with solutions of the flame retardants of the boric acid type and / or their salts at temperatures of 20 to 90 ° C, the impregnated particulate and / or fibrous lignocellulosic substances 55 to 170 ° C with partial curing of the melamine resins dried, and the impregnated particulate and / or fibrous lignocellulosic substances synergists are mixed as solids.

21. The method according to claim 19, characterized in that the particulate and / or fibrous lignocellulosic substances with Solutions of the flame retardants of the boric acid type and / or their salts are impregnated at temperatures of 20 to 90 ° C, the impregnated particulate and / or fibrous lignocellulosic substances are dried at 55 to 170 ° C and the impregnated particulate and / or 5 fibrous lignocellulosic substances synergists and melamine resins as

Solids are added.

22. The method according to claim 19, characterized in that the particulate and / or fibrous lignocellulosic substances with 0 solutions and / or dispersions of the flame retardants of the boric acid type and / or their salts and synergists are impregnated at temperatures of 20 to 90 ° C, which impregnated Particulate and / or fibrous lignocellulosic substances are dried at 55 to 170 ° C. and the impregnated particulate and / or fibrous lignocellulosescr en5 substances are mixed with melamine resins as a solid.

23. The method according to at least one of claims 19 to 22, characterized in that the further additives are added to the melamine resins, the flame retardants of the boric acid type and / or their salts and / or en o synergists.

24. Molding compositions for the production of flame-retardant lignocellulosic composites, 5 produced by

dry premixing of the components

-40 to 95% by mass of flame retardant mixture according to at least one of Claims 1 to 8, -5 to 60% by mass of thermoset prepolymers of the phenolic, urea, melamine, guanidine, cyanamide and / or aniline type and -0.1 to 10% by weight of processing aids and / or auxiliaries,

and granulation.

25. Molding compositions according to claim 24, characterized in that the production takes place by melt compounding following the dry premixing of the components at 100 to 170 ° C and granulation.

26. Flame retardant lignocellulosic composites, produced by extrusion, injection molding or pressing of the molding compositions according to claim 24 or 25 and curing.

27. Use of the lignocellulosic composites according to claim 26 as flame-retardant semi-finished products and molding materials for outdoor applications in the construction and leisure sectors.