Halogen-free flame retardant compositions and use of said compositions for direct and indirect fireproofing layers on substrates

Abstract

The present invention relates to aqueous fire retardant compositions. It further relates to an improved method of imparting fire retardancy to wood and cellulosic materials which can be used for the production of furniture and interior building construction, such as wood and panel materials, such as wood (timber) and engineered wood, such as plywood, laminated wood, fiberboard (e.g. medium density fiberboard (MDF) or high density fiberboard (HDF)), particle board (PB), oriented strand board (OSB), laminated wood, parallel strand lumber (PSL), long strand shavings laminated wood (LSL) and oriented strand lumber (OSL), glued laminated wood (glulam) and laminated veneer lumber (LVL), as well as materials for decorative interior trim, such as decorative panels prepared from chipboard (CB) or chipboard laminate (CL).

Description

[0001] The present invention relates to an aqueous flame retardant composition. It further relates to an improved method of imparting flame retardancy to wood-based and cellulose-based materials which can be used for the production of furniture and interior building construction, such as wood-based materials, such as wood (timber) and engineered wood, such as plywood, laminated wood, fiberboard (e.g. medium density fiberboard (MDF) or high density fiberboard (HDF)), particle board (PB), oriented strand board (OSB), laminated wood, parallel strand lumber (PSL), long strand layer lumber (LSL) and oriented strand lumber (OSL), glued laminated wood (glulam) and laminated veneer lumber (LVL), as well as materials for decorative interior, such as decorative panels. Such materials are also referred to as "substrates" in the following.

[0002] [Description] [TECHNICAL FIELD]

[0003] The present invention provides an aqueous flame retardant composition. It further provides an improved method of imparting flame retardancy to wood-based and cellulose-based materials which can be used for the production of furniture and interior building construction, such as wood-based materials, such as wood (timber) and engineered wood, such as plywood, laminated wood, fiberboard (e.g. medium density fiberboard (MDF) or high density fiberboard (HDF)), particle board (PB), oriented strand board (OSB), laminated wood, parallel strand lumber (PSL), long strand layer lumber (LSL) and oriented strand lumber (OSL), glued laminated wood (glulam) and laminated veneer lumber (LVL), as well as materials for decorative interior, such as decorative panels. [BACKGROUND]

[0004] Wood-based and cellulose-based materials are widely used as construction for building materials and furniture. Furthermore, decorative panels are commonly used in the construction of furniture and in decorative interiors. From the aspect of safety in case of fire, the materials have to meet high standards of flame retardancy.

[0005] The European standard DIN EN 13823 is widely accepted for comparing the flame retardancy of different materials. Some older methods which still give reliable results are ISO 5658-2 (2006) and UNI 9174 (2010). Based on these methods, the materials can be classified (e.g. according to Euroclass of DIN EN 13501-1 (2019-05)).

[0006] When following the Euroclass system, the classification of combustible materials, such as wood-based and cellulosic materials, such as wood-based panels and oriented strand boards, is based on the results of the single burning item (SBI) test according to DIN EN 13823. The classification parameters of the SBI test are the fire growth rate index (FIGRA), the lateral flame spread (LFS), the total release heat (THR 600s ), the smoke growth rate (SMOGRA) and the total smoke production (TSP). The FIGRA and the THR index are the main factors on which the Euroclass rating relies.

[0007] In order to increase their fire retardancy, wood-based and cellulosic materials can be treated with fire retardant compositions and intumescent compositions. Fire retardant compositions can slow down the spread of fire by absorbing energy that would otherwise be used for the continuation of the combustion process. Intumescent compositions expand under the influence of heat to form a massive foam layer (intumescent char) that insulates the substrate from heat, thus slowing down the pyrolysis of the substrate. Furthermore, the intumescent char prevents oxygen from contacting the substrate, thus suppressing combustion.

[0008] Typical intumescent compositions contain an acid donor, a carbon donor and a blowing agent. Upon exposure to heat, the acid donor decomposes to release an acid. The acid in turn catalyzes the carbonization of the carbon donor to form a carbon layer, and the decomposition of the blowing agent to release an inert gas. The inert gas serves to expand the carbon skeleton formed by the carbonization of the carbon donor, thus producing intumescent char. As suitable acid donors, phosphates are known. As carbon donors, polyols or sugars can be used. As blowing agents, nitrogen-containing compounds have been used, such as dicyandiamide, melamine, urea or guanidine. Compositions using melamine as blowing agent are known, for example from US 2012 / 0295996 A1, US 6,989,113 B1 and WO 2018 / 122406 A1.

[0009] From an environmental and economic point of view, it is desirable and advantageous to formulate water-based intumescent compositions, preferably halogen-free compositions. However, when trying to prepare such compositions, solubility and compatibility issues have to be dealt with.

[0010] Different methods have been described for treating substrates, such as wood-based materials, e.g. wood-based panels or balsa, with flame retardant additives. A common approach involves the addition of flame retardant additives to the wood raw material, such as strands, chips or fibres, before forming the compressed board, as described for example in DE 103 61 878 A1, EP 2 586 849 A2 and WO 2018 / 122406 A1. However, in this approach, a large amount of active agent is required, since the active agent is finally contained in the entire volume of the finished product. Furthermore, raw materials that have been treated with aqueous solutions can be prone to subsequent leaching of the active agent. Finally, compatibility problems between the active agent and the binder or resin used to form the product from the treated raw material can also arise.

[0011] The flame retardant can be added as particulate matter to the wood particles in the case of the production of particle boards, or as a liquid suspension, dispersion or solution to the fibres in the case of the production of fibre boards or oriented strand boards. In this case, compatibility between the active agent and the binder can also be a problem, and the use of a large amount of active agent is still required.

[0012] Non-patent document 1 describes the use of a flame-retardant adhesive resin consisting of a mixture of ammonium polyphosphate (APP), pentaerythritol (PER) and melamine-urea-formaldehyde resin (MUF) for the production of flame-retardant decorative (FRD) plywood.

[0013] With respect to wood-based and cellulosic substrates, the use of flame retardants and intumescent compositions as a topcoat seems to have received little attention. In particular, the treatment of such substrates with aqueous compositions does not appear to have been extensively investigated. However, an example of an aqueous intumescent composition for coating a substrate is described in WO 99 / 35196 A1.

[0014] Intumescent coatings based on a mixture of melamine-formaldehyde resin and metaphosphates are described in documents such as DE 43 07 406 A1 and WO 99 / 35196 A1. However, since metaphosphates are relatively expensive, it would be desirable to find a means for reducing their use or to be able to replace them completely, while at the same time maintaining sufficient intumescence. Furthermore, when applying a coating prepared using phosphates, it is recommended to apply a protective facing, thereby increasing further effort and costs. Avoiding the use of metaphosphates would also be advantageous in view of their high acidity.

[0015] In addition to potential compatibility problems, methods for applying flame retardants or intumescent coatings to the surface of a substrate are faced with the obstacle of ensuring that the coating does not deteriorate excessively as a result of handling operations and / or exposure to elements. In other words, in contrast to flame retardants added to the raw material in the production process of wood-based materials, flame retardants or intumescent compositions in the form of a coating not only need to show sufficient stability, but also need to show sufficient durability.

[0016] Non-patent literature 1:

[0017] Wu M, Song W, Wu Y, Qu W. Preparation and Characterization of the Flame Retardant Decorated Plywood Based on the Intumescent Flame Retardant Adhesive Materials (Basel). 2020 Feb 3; 13(3): 676. doi: 10.3390 / ma13030676. PMID: 32028679; PMCID: PMC7040706.

[0018] Objectives

[0019] The present inventors have sought to solve the problems discussed above and provide a means for imparting flame retardancy to substrates such as wood-based and cellulosic materials that can be used to produce furniture and interior building construction, and materials for decorative interior trim, which is more effective than previous means, and does not cause any loss in the flame retardancy and physical properties of the treated products.

[0020] It is therefore an object of the present invention to provide an improved flame retardant composition, in particular an improved water-containing intumescent composition for improving the flame retardancy of wood-based and cellulosic materials. It is a further object to provide an improved method for imparting flame retardancy to wood-based and cellulosic materials. [SUMMARY]

[0021] The present invention solves the identified problems by the water-containing flame retardant composition (B), the water-containing intumescent composition (C) and the method for imparting flame retardancy to substrates described below.

[0022] By using the water-containing flame retardant composition (B), the water-containing intumescent composition (C) and the method for imparting flame retardancy to substrates described below, it is possible to obtain materials showing excellent flame retardancy using only a small amount of active agent. In particular, compared to conventional methods and compositions, the present invention achieves a significant reduction in the amount of flame retardant required to achieve a specific fire reaction performance (e.g. a specific classification level in the Euroclass system). For example, the amount of flame retardant used in the preparation of low combustible wood-based composite panels is typically 70-80 kg / m 3whereas the present invention requires only a fraction of this amount to achieve comparable performance. This reduction in the amount of flame retardant required represents an improvement, not only from an economic point of view, but also from an ecological point of view. Moreover, the compositions are halogen-free. These compositions are generally considered to be safer, non-toxic and do not accumulate in the environment or in living organisms.

[0023] Furthermore, by relying on a coating process, rather than on the addition of raw materials, it is possible to separate the process of manufacturing the substrate from the process of treating the substrate with the flame retardant. Thus, it is possible to eliminate the need to run at low temperature and to employ long pressing times in the production of materials such as flame retardant wood-based panels, and to increase productivity. Finally, the compositions and methods of the present invention enable to obtain a coating that is sufficiently stable and durable to allow the use of the treated product in interior construction applications, thus eliminating the need to apply a further outer coating.

[0024] In particular, the present invention relates to the method of claim 1. Further embodiments are described in the dependent claims.

[0025] In another aspect, the present invention also relates to the aqueous flame retardant composition of claim 18 and to the aqueous intumescent composition of claim 21.

[0026] Finally, the present invention also relates to the intumescent support of claim 25 and to the flame retardant product of claim 29 or 30. [DETAILED DESCRIPTION]

[0027] [Resinous aqueous solution (A)]

[0028] In the present invention, as the resinous aqueous solution (A), it is possible to use a melamine-formaldehyde resinous aqueous solution, a melamine-urea-formaldehyde resinous aqueous solution, mixtures thereof and mixtures thereof with urea-formaldehyde resinous aqueous solutions and / or phenol-formaldehyde resinous aqueous solutions.

[0029] The resin component contained in the resinous aqueous solution (A) has a dual function. On the one hand, the resin acts as a binder, which enables the formation of a stable coating. On the other hand, the melamine contained in the resinous aqueous solution (A) acts as a blowing agent upon exposure to heat, thus participating in the intumescent action of the coating. The dual function of the resin component makes it possible to eliminate the use of polyvinyl acetate (PVA) / acrylate mixtures, which were previously commonly used as binders for intumescent compositions. Thus, a reduction in the total number of components contained in the treated substrate is achieved, and the probability of encountering incompatibilities between the components is reduced. Moreover, it has been found that melamine-type coatings are more durable and elastic than PVA-type coatings.

[0030] Surprisingly, the inventors have found that it is possible to produce intumescent coatings showing superior properties using an aqueous resin composition. It is therefore believed that the reason lies in the fact that the melamine component is dissolved and thus present in the form of solute particles which are one or more orders of magnitude smaller in size than the solid resin particles, rather than being dispersed in the form of solid melamine particles of relatively large size in the range of mm or pm as is the case in commonly used flame retardant compositions. The presence of the dissolved form and the reduction in particle size associated therewith not only allows for a better distribution of the resin in the intumescent composition, but ultimately also serves to increase the reactivity of the intumescent coating since the resin component shows a greater reaction surface and is more evenly distributed.

[0031] A further advantage resulting from the use of a melamine or melamine component solution rather than a solid lies in the fact that the acid donor (b) and the carbon donor (c) will be encapsulated by the resin during curing, locking them in place, protecting them from any interference and consolidating the even distribution of the components.

[0032] The even distribution of the components present in the resin solution (A) ultimately reflected in the intumescent coating makes it possible to observe an increased and more uniform reactivity when comparing the effectiveness of the intumescent coating as described herein to other intumescent coatings. The increased uniformity of the component distribution allows for a reduction in the amount of coating compared to the prior art, while at the same time making it possible to form an intumescent char showing better structure and stability, thus improving the overall flame retardancy of the treated substrate.

[0033] The melamine-formaldehyde resin aqueous solution, the melamine-urea-formaldehyde resin aqueous solution, the urea-formaldehyde resin aqueous solution and the phenol-formaldehyde resin aqueous solution to be incorporated into the resin aqueous solution (A) can be obtained from the respective raw materials, i.e. melamine, formaldehyde, urea and phenol, by methods commonly used in the art, for example by the method described in EP 0767 214 A1, wherein an aqueous mixture of the individual components is reacted to produce the resin solution and, if necessary, the solids of the resin solution are adjusted by further addition or removal of water.

[0034] As an alternative, commercially available resin powders or resin solutions can be used to prepare the resin aqueous solution (A). Examples of commercially available resin powders and resin aqueous solutions which can be used in the present application include, but are not limited to (urea-formaldehyde type produced by BASF), (melamine-formaldehyde and melamine-urea-formaldehyde type produced by BASF), (phenol-formaldehyde type produced by Hexion GmbH) and (melamine-formaldehyde type produced by Prefere Resins).

[0035] The resin aqueous solution (A) used in the present application shows a total melamine content of 20 to 45 wt.-%, preferably 25 to 35 wt.-%, relative to the total weight of the resin aqueous solution (A). When the melamine content is in this range, a uniform and stable coating can be formed using the aqueous intumescent composition (C) as further described below, allowing to achieve an excellent flame retardancy, while also allowing the coating to show a good durability and mechanical stability. When preparing the resin aqueous solution from the corresponding raw materials, the melamine content can be adjusted by varying the amount of melamine used in the reaction. When using a commercially available resin powder or resin solution, its melamine content is usually determined by the supplier. However, if necessary, the melamine content can also be determined by a method as described in the database of the German Federal Institute for Risk Evaluation (BfR) (“Methodensammlung Papier, Karton und Pappe”, Section 5: “Bestimmung von Einzelsubstanzen”, Subsection 5.3, “Melamin”; https: / / www.bfr.bund.de / cm / 343 / melamin-aus-melamin-formaldehydharz.pdf; accessed on November 17, 2020; and Frind, H.; Hensel, R.; Pommer, W: 3.4.1 Melamin aus Melamin- Formaldehydharz. In: Methoden zur Untersuchung von Papieren, Kartons und Pappen für Lebensmittelverpackungen. Erich Goltze 1982).

[0036] From the point of view of ease of handling and operation, the resin aqueous solution (A) preferably shows a solids content (a A ) of 45 to 75 wt.-%, more preferably 50 to 70 wt.-%, and even more preferably 55 to 65 wt.-%, relative to the total weight of the resin aqueous solution (A). The solids content is determined according to DIN 53216-1 (1989).

[0037] From the point of view of avoiding brittleness and / or improving the transparency of the coating, the resin aqueous solution (A) is preferably:

[0038] a mixture of a melamine-formaldehyde (MF) resin aqueous solution and a urea-formaldehyde (UF) resin aqueous solution, or

[0039] a mixture of a melamine-formaldehyde (MF) resin aqueous solution and a urea-formaldehyde (UF) resin aqueous solution, or

[0040] - a mixture of a melamine-formaldehyde (MF) resin aqueous solution with a phenol-formaldehyde (PF) resin aqueous solution and a urea-formaldehyde (UF) resin.

[0041] In all these cases, the mass ratio of the solid content (a MF ) derived from the melamine-formaldehyde resin aqueous solution to the solid content (a X ) derived from all the resin components except the melamine-formaldehyde resin aqueous solution is preferably 2:1 to 10:1, more preferably 3:1 to 9:1, and even more preferably 4:1 to 8:1.

[0042] [acid donor (b) and carbon donor (c)]

[0043] Examples of the acid donor (b) for use in the present application include ammonium polyphosphate, amidine-based phosphoric acid, guanidine-based phosphoric acid, and mixtures thereof. One or more selected from the group consisting of ammonium polyphosphate, amidine-based phosphoric acid, and guanidine-based phosphoric acid, preferably one or more selected from the group consisting of ammonium polyphosphate and guanidine-based phosphoric acid, are used as the acid donor (b). This is from the viewpoint of maximizing the flame retardancy of the coating while avoiding the use of compounds showing high acidity. The use of the compounds is also considered to minimize health and environmental risks.

[0044] Examples of the carbon donor (c) for use in the present application include glucose, arabinose, and other monosaccharides; lactose, maltose, and other disaccharides; starch, cellulose, dextrin, and other polysaccharides; sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol, and other polyols; and mixtures thereof. One or more selected from the group consisting of starch, cellulose, dextrin, and other polysaccharides; sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol, and other polyols, and mixtures thereof are preferably used as the carbon donor (c). From the viewpoint of achieving uniform distribution of the components, the carbon donor (c) is more preferably one or more selected from the group consisting of sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol, and mixtures thereof, and even more preferably one or more selected from the group consisting of sorbitol, pentaerythritol, and dipentaerythritol. The use of the compounds is also considered to minimize health and environmental risks.

[0045] The acid donor (b) and the carbon donor (c) are generally used in the form of a granular powder in which at least 90% of the particles present have a particle size of less than 100 pm, and preferably at least 90% of the particles have a particle size of less than 50 pm, or at least 50% of the particles have a particle size of less than 10 pm. The average particle size of the powder can be determined by the laser diffraction method (ISO 13320 (2019)).

[0046] In the method and composition of the present application, the mass ratio of the acid donor (b) to the carbon donor (c) of the acid donor (b) and the carbon donor (c) used is from 10:1 to 1:1, preferably from 8:1 to 1:1, more preferably from 6:1 to 1:1, still more preferably from 6:1 to 2:1, most preferably from 5:1 to 3:1. When the mass ratio of the acid donor (b) to the carbon donor (c) falls within this range, a uniform and stable coating can be formed using the aqueous flame retardant composition (B) or the aqueous intumescent composition (C) as further described below, thereby allowing excellent flame retardancy to be achieved.

[0047] [Method of imparting flame retardancy]

[0048] A method of imparting flame retardancy to a wood or cellulose-based material for producing furniture, interior architectural structures, or decorative interior trim, the method comprising the following steps (1) and (2):

[0049] (1) introducing an acid donor (b) and a carbon donor (c) into a resin aqueous solution (A) to obtain an aqueous intumescent composition (C), wherein

[0050] The resin aqueous solution (A) is selected from the group consisting of a melamine-formaldehyde resin aqueous solution, a melamine-urea-formaldehyde resin aqueous solution, mixtures thereof, and mixtures thereof with urea-formaldehyde resin aqueous solutions and / or phenol-formaldehyde resin aqueous solutions; wherein

[0051] The resin aqueous solution (A) exhibits a total melamine content of from 20 to 45% by weight, preferably from 25 to 35% by weight, relative to the total weight of the resin aqueous solution (A);

[0052] The acid donor (b) is selected from the group consisting of ammonium polyphosphate, phosphoric acid amidinourea, phosphoric acid guanidine, and mixtures thereof;

[0053] The carbon donor (c) is selected from the group consisting of glucose, arabinose and other monosaccharides, lactose, maltose and other disaccharides, starch, cellulose, dextrin and other polysaccharides, sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol or other polyols, and mixtures thereof;

[0054] The mass ratio of the acid donor (b) to the carbon donor (c) of the acid donor (b) and the carbon donor (c) introduced into the resin aqueous solution (A) is from 10:1 to 1:1, preferably from 8:1 to 1:1, more preferably from 6:1 to 1:1; and

[0055] The amount of the acid donor (b) and the carbon donor (c) introduced into the resin aqueous solution (A) is such that the mass ratio of the solids (a A ) of the resin aqueous solution (A) to the total amount of the acid donor (b) and the carbon donor (c) (a A): (b) + (c) is 0.25:1 to 5:1, preferably 0.30:1 to 2.5:1;

[0056] The aqueous intumescent composition (C) exhibits 50 to 80 wt.-%, preferably 60 to 75 wt.-% solids (a C ) relative to the total weight of the aqueous intumescent composition (C);

[0057] (2) a step (2A) of applying the aqueous intumescent composition (C) to the wood-based material, or

[0058] a step (2B) of laminating one or more layers of intumescent carrier and decorative paper to the wood-based or cellulose-based material in a specified order,

[0059] wherein the intumescent carrier comprises kraft paper or a mat made of glass or other fibers which has been coated with the aqueous intumescent composition (C).

[0060] [Preparation of the aqueous intumescent composition (C)]

[0061] In step (1) of a method for imparting flame retardancy to a wood-based or cellulose-based material for the production of furniture, interior construction or decorative interior trim, an acid donor (b) and a carbon donor (c) are introduced into the aqueous resin solution (A) to obtain an aqueous intumescent composition (C).

[0062] Before their introduction into the aqueous resin solution (A), the acid donor (b) and the carbon donor (c) can be dispersed or suspended in water to form an aqueous flame retardant composition (B). When doing so, the acid donor (b) and the carbon donor (c) can be added to the water separately or together. Subsequently, the aqueous flame retardant composition (B) is added to the aqueous resin solution (A). As an alternative, the acid donor (b) and the carbon donor (c) can be introduced into the aqueous resin solution (A) as a granular powder.

[0063] Water can be added to the aqueous resin solution (A) simultaneously or subsequently to the introduction of the flame retardant components into the aqueous resin solution (A) to adjust the concentration of the components and / or solids of the aqueous intumescent composition (C) to the level required for the intended field of application and the intended means of applying the intumescent composition (C).

[0064] When the acid donor (b), the carbon donor (c) and optionally additional water are introduced into the aqueous resin solution (A) separately, this can be done simultaneously or sequentially.

[0065] As a result of the introduction of the acid donor (b) and the carbon donor (c) into the aqueous resin solution (A), an aqueous intumescent composition (C) is obtained.

[0066] To achieve a uniform distribution of components, the aqueous resin solution (A) can be stirred during the introduction of the acid donor (b) and carbon donor (c) or the addition of the aqueous flame retardant composition (B). Such stirring can be performed using a type of mixer commonly used in the art, such as a dispersion mixer or a propeller mixer.

[0067] When forming an aqueous flame retardant composition (B) by introducing the acid donor (b) and carbon donor (c) into water and then into the resin aqueous solution (A), this is preferably done while the water is being stirred using a dispersion mixer. In this case, the introduction of the acid donor (b) and carbon donor (c) may also be done simultaneously or sequentially.

[0068] The aqueous flame retardant composition (B) comprises, relative to the total weight of the aqueous flame retardant composition (B), a total of 40 to 80% by weight, preferably 45 to 75% by weight, more preferably 55 to 70% by weight, of an acid donor (b) and a carbon donor (c).

[0069] Optionally, the aqueous flame retardant composition (B) and the aqueous swelling composition (C) can be further formulated to include a functional compound comprising 0.5 to 10% by weight, preferably 1 to 5% by weight, relative to the total weight of the acid donor (b) and the carbon donor (c), said functional compound being selected from the group consisting of aluminosilicates, calcium and magnesium silicates, such as wollastonite or talc, silica, titanium dioxide, aluminum hydroxide, calcium and magnesium phosphates, and mixtures thereof. The functional compound can be added to the aqueous flame retardant composition (B) simultaneously with the acid donor (b) and the carbon donor (c). In the case where the acid donor (b) and the carbon donor (c) are added directly to the aqueous resin solution (A) to form the aqueous swelling composition (C), the functional compound can be introduced into the aqueous resin solution (A) alone or together with the acid donor (b) and the carbon donor (c).

[0070] Acid donor (b) and carbon donor (c) are introduced into resin aqueous solution (A), such that the solids (a) in resin aqueous solution (A) are... A The mass ratio of (a) to the total amount of added acid donor (b) and carbon donor (c) A The ratio of (b) to (c) is 0.25:1 to 5:1, preferably 0.30:1 to 2.5:1. This also applies when the acid donor (b) and carbon donor (c) are introduced into the aqueous resin solution (A) in the form of an aqueous flame retardant composition (B). When the solids of the aqueous resin solution (A) are... A The total amount of acid donor (b) and carbon donor (c) (a) AWhen the mass ratio of (b) + (c) is within the range, a uniform and stable coating can be formed using the aqueous intumescent composition (C), thereby allowing excellent flame retardancy to be obtained. Furthermore, the coating will also exhibit good durability and mechanical stability, thereby eliminating the need to apply an additional outer coating.

[0071] The aqueous intumescent composition (C) generally has 50 to 80% by weight, preferably 60 to 75% by weight, of solids (a C ) relative to the total weight of the aqueous intumescent composition (C). When the solids (a C ) of the aqueous intumescent composition (C) are within the range, the properties of the aqueous intumescent composition (C) will be achieved, for example, good handling. In particular, the aqueous intumescent composition (C) can be easily applied using methods and procedures commonly used in the art.

[0072] Optionally, additional additives (d) such as melamine, urea, curing agents, flow agents, antifoams and dyes can be added to the aqueous intumescent composition (C).

[0073] The amount of additive (d) added is not limited as long as the flame retardancy of the treated substrate is not impaired. However, the total amount of additive (d) added generally does not exceed 5% by weight relative to the total weight of the aqueous intumescent composition (C).

[0074] The additive (d) can be added to the aqueous resin solution (A) before, simultaneously with or after the introduction of the acid donor (b) and the carbon donor (c). The additive (d) can also be mixed with the acid donor (b) and / or the carbon donor (c) at a stage prior to combination with the aqueous resin solution (A).

[0075] The materials that can be treated with the aqueous intumescent composition (C) ("substrates") include, but are not limited to, materials used for the production of furniture and interior construction, such as wood-based materials, for example wood (timber) and engineered wood, such as plywood, reinforced wood, fiberboard (for example medium density fiberboard (MDF) or high density fiberboard (HDF)), particle board (PB), oriented strand board (OSB), laminated wood, parallel strand lumber (PSL), long strand shive lumber (LSL) and oriented strand lumber (OSL), glued laminated timber (glulam) and laminated veneer lumber (LVL), plastic reinforced substrates, such as wood-based thermal insulation boards or wood-plastic composites, and materials for decorative interior trim. In addition to wood-based materials, the aqueous intumescent composition (C) can also be used to treat other materials to which flame retardant coatings are typically applied, as long as these materials are compatible with aqueous systems.

[0076] The composition is halogen-free. There is currently a high demand for halogen-free compositions as halogen-containing compositions are considered to be toxic and can leach into the environment. Furthermore, they are generally not biodegradable. Therefore, providing halogen-free compositions ensures a safer way of passive fire protection.

[0077] [Application of the aqueous intumescent composition (C)]

[0078] In step (2) of the process for imparting flame retardancy, the aqueous intumescent composition (C) is applied to the substrate. This can be done by methods and procedures commonly used in the art, for example by spraying, pouring, blade coating, roll coating or brushing.

[0079] The applied coating will dry and self-cure at room temperature. However, the process can also be accelerated by employing convective and / or radiative heat transfer devices, for example a hot air gun or a drying lamp. A curing agent can also be included in the aqueous intumescent composition (C) in order to accelerate the curing process.

[0080] During the curing process, cross-linking of the resin component will occur, thereby encapsulating the acid donor (b) and the carbon donor (c) with the melamine in the resin and locking them into place within the coating. Thereby, a durable coating is formed in which the uniform distribution of the components is consolidated, while the components are protected from any interference.

[0081] The coating can be applied to one or more sides of the substrate. When this is done, the amount of coating applied to any given side is preferably 40 to 400 g / m 2 , more preferably 60 to 200 g / m 2 , and even more preferably 80 to 150 g / m 2 , calculated on the total amount of acid donor (b) and carbon donor (c).

[0082] The inventors have found that a coating amount of 40 to 150 g / m 2 , calculated on the total amount of acid donor (b) and carbon donor (c), is sufficient for most fields of application for the treated substrate to show excellent flame retardancy. For specialized applications or in order to achieve excellent flame retardancy, a coating amount of 150 g / m 2 , calculated on the total amount of acid donor (b) and carbon donor (c), can be used. For example, when the aqueous intumescent composition (C) is applied to a material intended for use in a roof application, it can be considered to increase the coating amount in order to increase the amount of intumescent char formed upon exposure to fire. This will help to ensure that the joints between the roof elements will be completely covered by intumescent char and prevent the fire from spreading to the insulation material located behind the roof elements, which is usually composed of highly flammable polyurethane or polyisocyanurate foam. The increased coating amount will also allow a significant reduction of the burn-through rate.

[0083] Depending on the substrate, it can be necessary to split step (2) of applying the aqueous intumescent composition (C) into two or more steps of sequentially applying a coating layer comprising a lower amount of the aqueous intumescent composition (C) in order to obtain a uniform and high quality coating, especially when applying a coating weight close to 400 g / m2of value. Of course, such a repeated application strategy can be used for any substrate or coating weight. If two or more coating layers are applied to the substrate, the applied coating layer should be allowed to dry and cure before applying the subsequent coating layer. 2

[0084] In case the aqueous intumescent composition (C) is used for fireproof wood-based decorative panels, the intumescent coating is applied to the panel substrate prior to the application of the decorative paper. When assessing the fire retardancy of a decorative panel treated in this way, the inventors observed that part of the decorative paper constituting the outer surface of the decorative panel can crumble during exposure to fire. It was also found that part of the intumescent coating can be taken away with the decorative paper fragments.

[0085] When using the aqueous intumescent composition (C) for fireproof decorative panels, the potential loss of intumescent coating due to the peeling of part of the decorative paper can be compensated by using a higher coating weight. Nevertheless, the inventors have also developed an alternative to ensure that sufficient fire retardancy is retained despite the possible peeling during exposure to fire. In this method, the aqueous intumescent composition (C) is not applied directly to the panel substrate, but one or more layers of an intumescent carrier, such as kraft paper that has already been coated with the aqueous intumescent composition (C) or a mat made of glass or other fibers, are applied to the panel substrate prior to the application of the decorative paper. When one or more layers of intumescent carrier are located between the panel substrate and the decorative paper, the loss of fire retardancy of the decorative panel due to the peeling of part of the decorative paper can be prevented. In addition, this method also allows to expand the range of treatable materials to include hydrophobic substrates, such as CB and CL, such as HPL and CPL.

[0086] In the following, the method with intumescent carrier will also be referred to as “indirect coating method”.

[0087] In the indirect coating method, in step (2), the kraft paper or mat made of glass or other fibers (hereinafter also referred to as “substrate for intumescent carrier”) is coated with the aqueous intumescent composition (C) and then one or more layers of the intumescent carrier are laminated to the substrate together with the decorative paper.

[0088] The type of kraft paper that can be used as substrate for intumescent carrier is not particularly limited and any kraft paper commonly used in the art can be used. Examples thereof are soda kraft paper. Commercially available kraft papers can be used, such as the ones by Zellstoff ​AG provided Brands or paper provided by APV Germany GmbH. Such kraft paper generally exhibits a grammage of 40 to 300 g / m 2 . From the viewpoint of easy handling and manipulation of the kraft paper before and after coating with the aqueous intumescent composition (C), the grammage of the kraft paper is preferably 60 to 200 g / m 2 , more preferably 80 to 150 g / m 2 . When the grammage of the kraft paper is within the range described, it is also possible to apply a high amount of the acid donor (b) and the carbon donor (c) when the kraft paper is coated with the aqueous intumescent composition (C).

[0089] The type of the mat made of glass or other fibers which can be used as the substrate for the intumescent carrier is not particularly limited, and any mat made of glass or other fibers commonly used in the art can be used. Such materials are available, for example, from Johns Manville Corp. From the viewpoint of easy handling and manipulation of the mat made of glass or other fibers before and after coating with the aqueous intumescent composition (C), the grammage of the mat made of glass or other fibers is generally 60 to 300 g / m 2 , preferably 80 to 200 g / m 2 . When the grammage of the mat made of glass or other fibers is within the range described, it is also possible to apply a high amount of the acid donor (b) and the carbon donor (c) when the mat made of glass or other fibers is coated with the aqueous intumescent composition (C).

[0090] Hereinafter, the kraft paper or the mat made of glass or other fibers which has been coated with the aqueous intumescent composition (C) will also be referred to as "treated kraft paper" or "treated mat".

[0091] In order to enable the intumescent carrier to be easily laminated with the substrate and the decorative paper, the substrate for the intumescent carrier can be impregnated with an adhesive resin before coating with the aqueous intumescent composition (C). As the adhesive, the same aqueous resin solution (A) as described above, for example, an aqueous melamine-formaldehyde resin solution, an aqueous melamine-urea-formaldehyde resin solution, an aqueous urea-formaldehyde resin solution, and / or an aqueous phenol-formaldehyde resin solution can be used. However, the adhesive is not limited to such resin solutions, and any adhesive which does not impair the application of the aqueous intumescent composition (C) can be used. The type and amount of the adhesive resin to be impregnated can vary depending on the type of the substrate and the decorative paper intended to be used, but the impregnation amount will generally be 40 to 400 g / m 2 .

[0092] Impregnation of the substrate for intumescent carrier with the binder resin and coating with the aqueous intumescent composition (C) can be carried out using a machine, for example those produced by the company Vits. In particular, it is possible to use devices as described, for example, in DE 198 14 212 C1, DE 199 01 525 A1 or DE 199 46 325 A1. When using such devices, the amount of binder impregnated into the substrate for intumescent carrier and the amount of aqueous intumescent composition (C) coated thereon can be adjusted by adjusting the working parameters of the device.

[0093] In the case where the substrate for intumescent carrier is impregnated with the binder resin before being coated with the aqueous intumescent composition (C), impregnation of the substrate for intumescent carrier with the binder resin and coating with the aqueous intumescent composition (C) can be carried out as consecutive steps of a single process. This can be done by using an application system for liquid coverage (e.g. an ARP coater).

[0094] While it is theoretically possible to coat the intumescent composition on both sides of the substrate for intumescent carrier, the inventors have surprisingly found that the best fire retardancy is obtained when coating the aqueous intumescent composition (C) on only one side of the substrate for intumescent carrier and further arranging the intumescent carrier such that its intumescent coating side faces away from the substrate.

[0095] From the point of view of ease of handling and operation and obtaining the best fire retardancy, the amount of aqueous intumescent composition (C) coated on the substrate for intumescent carrier, calculated on the total amount of acid donor (b) and carbon donor (c), is preferably from 30 to 200 g / m 2 , more preferably from 40 to 150 g / m 2 , still more preferably from 60 to 120 g / m 2 .

[0096] The type of decorative paper that can be used in the preparation of the fire-retardant decorative panel by indirect coating method is not particularly limited and any decorative paper commonly used in the art that is commercially available can be used.

[0097] Depending on the final intended use of the decorative panel, one or more layers of the combination of intumescent carrier and decorative paper can be laminated to one or both sides of the substrate. When doing so, the intumescent coating side of each intumescent carrier layer faces away from the substrate. Surprisingly, the inventors have found that this arrangement will result in the best fire retardancy.

[0098] If the decorative paper is applied on only one side of the substrate, a balancing paper can be laminated to the other side of the substrate to prevent warping.

[0099] Methods and conditions commonly used in the art can be used for the preparation of the laminate. Furthermore, in the case of the preparation of fire-retardant decorative panels based on a CB board and a CL board, the process of applying the intumescent carrier and the decorative paper can also be combined with the process of producing the substrate. In this case, the laminate can be prepared by stacking the elements to be composed of the laminate (from which the substrate or resin-impregnated core paper, the intumescent carrier and the decorative paper of the CB or CL board can be formed) and subsequently assembling the elements by means of a press. The exact processing conditions will vary depending on the properties of the substrate and the decorative paper, but will not go beyond those commonly employed in the art.

[0100] Examples of the arrangement of the layers that can be implemented in the preparation of the decorative panel are given below. However, the present application is not limited thereto.

[0101] A) decorative paper

[0102] one or more layers of intumescent carrier

[0103] substrate

[0104] one or more layers of intumescent carrier

[0105] decorative paper

[0106] B) decorative paper

[0107] one or more layers of intumescent carrier

[0108] substrate

[0109] balancing paper

[0110] If part of the decorative paper peels off during exposure to fire, part of the intumescent carrier can also detach. In view of this, from the perspective of optimizing the fire retardancy of the decorative panel, the use of more than one layer of intumescent carrier is preferred. It is even more preferred to use a multi-layered intumescent carrier containing different amounts of intumescent coating, wherein the layers are arranged such that the amount of intumescent coating on the adjacent layers continuously decreases from the layer adjoining the substrate to the layer adjoining the decorative paper, thereby effectively establishing a concentration gradient. For example, in the case of the use of two layers of intumescent carrier, the layer adjoining the decorative paper can be made to contain a coating amount of 40 g / m 2 of the total amount of acid donor (b) and carbon donor (c), and the layer adjoining the substrate can be made to contain a coating amount of 60 g / m 2 of the total amount of acid donor (b) and carbon donor (c).

[0111] The use of intumescent carriers to improve the fire retardancy of the substrate provides a further advantage of allowing the range of applications to be expanded. That is, the use of intumescent carriers makes it possible to also use hydrophobic substrates, such as CB boards and CL boards, for example high-pressure laminates (HPL) and continuous-pressure laminates (CPL).

[0112] The use of intumescent carriers to improve the flame retardancy of substrates also provides the following additional advantages: the intumescent carrier can be produced at a location different from the location where the laminate comprising the intumescent carrier is prepared and / or at a location different from the location where the treated product will be used or further processed. Thus, the weight and volume of material to be transported, and therefore also the transportation costs, can be reduced by transporting only the intumescent carrier to the location where the laminate comprising the intumescent carrier will be used and where the untreated substrate is already present (instead of having to transport the treated product). Furthermore, the packaging and transportation of the intumescent carrier can be simpler than the packaging and transportation of the treated product or ingredients required to form the intumescent composition.

[0113] The indirect coating method can also be extended so that intumescent compositions other than the aqueous intumescent composition (C) as described above are used. That is, when the intumescent carrier is coated with any intumescent composition comprising an acid, a char former and a blowing agent, the other advantages described above can be obtained. Suitable acid sources, char formers and blowing agents are the acid donor (b), the carbon donor (c) and the aqueous resin solution (A) as described above.

[0114] In a particularly preferred embodiment, the present application relates to a flame- retarded product comprising a wood or natural fiber based board or panel on which an intumescent carrier has been laminated, wherein the intumescent carrier comprises a kraft paper or a mat made of glass or other fibers to which an intumescent coating has been applied, the coating comprising a melamine containing resin such as an MF or MUF resin, a carbon donor selected from erythritol, pentaerythritol, di-pentaerythritol, tri-pentaerythritol, and an acid donor selected from ammonium polyphosphate and guanidine phosphate. Preferably, the melamine containing resin is a pre-condensed resin. In another preferred embodiment, the coating or composition applied to the carrier will be applied at a concentration of 20 to 100 g / 100 g carrier, preferably 20 to 75 g / 100 g carrier, more preferably 25 to 50 g / 100 g carrier.

[0115] [Advantages of the invention]

[0116] Thus, the present application provides an improved flame retardant composition, in particular an improved aqueous intumescent composition for imparting flame retardancy to a substrate. An improved method for imparting flame retardancy to a substrate is also provided.

[0117] The present application can eliminate organic solvents when formulating flame retardant compositions, thereby reducing environmental impact.

[0118] At the same time, it allows for a better distribution of the ingredients in the aqueous intumescent composition (C), thereby reducing the overall amount of material, in particular the amount of acid donor (b) and carbon donor (c) needed to impart a certain degree of flame retardancy to the substrate. This improvement acts as a further reduction of the environmental impact and also reduces the associated costs.

[0119] The aqueous resin solution used for the preparation of the aqueous intumescent composition (C) can in principle be identical to the resin solution used as a binder in the production of products such as particle boards or oriented strand boards, thereby making it possible to rely on raw materials already present at the production site for the preparation of the aqueous intumescent composition (C) and only the further acquisition of the ingredients for the preparation of the flame retardant composition (B) or for the preparation of such composition when it is intended to directly treat such substrates at their production site is necessary. The only treatment of the ingredients for the preparation of the flame retardant composition (B) also offers the advantage of being able to operate with solids or mixtures thereof which show a high degree of storage stability.

[0120] The aqueous intumescent composition (C) offers the advantage of being easy to handle, to work with and to apply. Furthermore, the coating formed therefrom, in which the acid donor (b) and the carbon donor (c) are encapsulated by the resin, combines stability and durability with excellent flame retardancy.

[0121] The advantage of the present invention over methods in which for example a flame retardant composition is added to the raw materials during the production of wood-based panels is the ability to use any conventional material as a substrate. This also means that the conditions for the production of the substrate do not have to take into account the presence of a flame retardant composition or intumescent composition and are therefore not limited thereto. In contrast to the method of the present invention, prior art methods in which the flame retardant additive is introduced at the same time as the production of the substrate itself would require a changeover time, lower temperatures and lower processing speeds, thereby resulting in a reduced productivity. Furthermore, the introduction of the flame retardant additive during the production of the substrate as carried out in the prior art would generally result in a requirement for the substrate to show a higher density and the necessity to use special glues in order for the product to show satisfactory mechanical properties.

[0122] The separation of the preparation of the intumescent composition from the production of the product to be treated also enables the optimization of the ratio of the resin ingredients to the flame retardant ingredients, i.e. the acid donor (b) and the carbon donor (c), since the resin contained in the intumescent composition does not need to perform the additional function of holding the ingredients making up the substrate together.

[0123] The indirect coating method of first applying the aqueous intumescent composition (C) to the substrate for the intumescent carrier enables the extension of the range of materials which can be treated to include hydrophobic substrates, thereby making it possible to prepare flame retardant decorative panels on the basis of chipboards (CB) and chipboard laminates (CL). Thus, the aqueous intumescent composition (C) is not only suitable for the treatment of materials used in construction projects, but also widely in the field of furniture construction and decorative interior.

[0124] The indirect coating method also offers the following further advantages: the expanded carrier can be produced at a location different from the location where the laminate containing the expanded carrier is assembled and / or at a location different from the location where the product to be used or further processed will be located.

[0125] The present invention will now be illustrated by specific embodiments. However, these embodiments are not intended to limit the invention in any way.

[0126] Example

[0127] Preparation of aqueous flame retardant composition (B) and aqueous intumescent composition (C)

[0128] Example 1

[0129] 80 parts by weight of ammonium polyphosphate (APP SD2-Ecochem) were mixed with 20 parts by weight of pentaerythritol (Penta F40-Ecochem). 65 parts by weight of the resulting mixture were alternately combined with 35 parts by weight of deionized water and then mixed using a dispersion mixer for 10 minutes to obtain an aqueous flame retardant composition (B) in suspension form.

[0130] 65 parts by weight of melamine with a content of 55% 650 is mixed with 35 parts by weight of deionized water to obtain a melamine content of approximately 36% and a solids content (a A A is a 65% aqueous solution of resin.

[0131] The water-containing flame retardant composition (B) is stirred to achieve a mass ratio (a) A A water-swellable composition (C) is prepared by mixing ((b)+(c)) (the ratio of solids derived from the aqueous resin solution (A) to flame-retardant components derived from the water-based flame retardant composition (B)) in an amount of 1:1.3 into the aqueous resin solution (A).

[0132] Example 2

[0133] 80 parts by weight of ammonium polyphosphate (APP SD2-Ecochem) and 20 parts by weight of pentaerythritol (Penta F40-Ecochem) were mixed to obtain the flame retardant component.

[0134] 65 parts by weight of melamine with a content of 55% 650 (BASF) was mixed with 35 parts by weight of deionized water to obtain a melamine content of approximately 36% and a solids content of (a A A is a 65% aqueous solution of resin.

[0135] An amount of the flame retardant ingredient, the resin aqueous solution (A) and water were mixed using a dispersion mixer, thereby obtaining an aqueous intumescent composition (C) containing 35% of water and showing a mass ratio (a A ):((b)+(c)) (ratio of solid content derived from the resin aqueous solution (A) to the flame retardant ingredient) of 1:1.3.

[0136] Example 3

[0137] An acid donor composition was prepared by mixing acid donor ingredients and functional compound silica of the types and relative amounts shown in Table 1.

[0138] A carbon donor composition was prepared by mixing carbon donor ingredients of the types and relative amounts shown in Table 1.

[0139] 80 parts by weight of the acid donor composition was mixed with 20 parts by weight of the carbon donor composition. 65 parts by weight of the resulting mixture was combined alternately with 35 parts by weight of deionized water, and then mixed for 10 minutes using a dispersion mixer, thereby obtaining an aqueous flame retardant composition (B) in the form of a suspension.

[0140] A resin aqueous solution (A) having a melamine content of about 29% and a solid content (a 650 (BASF), 13 parts by weight of 390 (BASF) and 35 parts by weight of deionized water was prepared. A

[0141] The aqueous flame retardant composition (B) was mixed with the resin aqueous solution (A) in an amount to obtain an aqueous intumescent composition (C) having a mass ratio (a A ):((b)+(c)) (ratio of solid content derived from the resin aqueous solution (A) to the flame retardant ingredient derived from the aqueous flame retardant composition (B)) of 1:1.3.

[0142] Example 4

[0143] An acid donor composition was prepared by mixing acid donor ingredients and functional compound silica of the types and relative amounts shown in Table 1.

[0144] A carbon donor composition was prepared by mixing carbon donor ingredients of the types and relative amounts shown in Table 1.

[0145] 80 parts by weight of the acid donor composition was mixed with 20 parts by weight of the carbon donor composition. 65 parts by weight of the resulting mixture was combined alternately with 35 parts by weight of deionized water, and then mixed for 10 minutes using a dispersion mixer, thereby obtaining an aqueous flame retardant composition (B) in the form of a suspension.

[0146] ​By using 52 parts by weight of melamine with a content of 55% 650 (BASF) was mixed with 26.3 parts by weight of deionized water to prepare melamine with a content of approximately 29% and a solids content of (a A A 65% aqueous resin solution (A) was then added while stirring the mixture. A 60% aqueous solution of PF 1981HD (HEXION).

[0147] A certain amount of aqueous flame retardant composition (B) is mixed with an aqueous resin solution (A) to obtain a mass ratio (a) A A water-swellable composition (C) having a ratio of solids derived from an aqueous resin solution (A) to flame-retardant components derived from an aqueous flame retardant composition (B) of 1:1.3.

[0148] Example 5

[0149] Acid donor compositions were prepared by mixing acid donor components of the types and relative amounts shown in Table 1 with the functional compound silica.

[0150] Carbon donor compositions were prepared by mixing carbon donor components of the types and relative amounts shown in Table 1.

[0151] 80 parts by weight of the acid donor composition were mixed with 20 parts by weight of the carbon donor composition. 65 parts by weight of the resulting mixture were alternately combined with 35 parts by weight of deionized water and then mixed with a dispersion mixer for 10 minutes to obtain an aqueous flame retardant composition (B) in suspension form.

[0152] By using 52 parts by weight of melamine with a content of 55% 650 (BASF), 6.5 parts by weight 390 (BASF) was mixed with 30.7 parts by weight of deionized water to prepare melamine with a content of approximately 29% and a solids content of (a A A 65% aqueous resin solution (A) was then added while stirring the mixture. A 60% aqueous solution of PF1981HD (HEXION).

[0153] A certain amount of aqueous flame retardant composition (B) is mixed with an aqueous resin solution (A) to obtain a mass ratio (a) A A water-swellable composition (C) having a ratio of solids derived from an aqueous resin solution (A) to flame-retardant components derived from an aqueous flame retardant composition (B) of 1:1.3.

[0154] Comparative Example 1

[0155] Ammonium polyphosphate (APP SD2 - Ecochem) 80 parts by weight was mixed with pentaerythritol (Penta F40 - Ecochem) 20 parts by weight. The resulting mixture 65 parts by weight was alternately combined with deionized water 35 parts by weight and then mixed for 10 minutes with a dispersing mixer, thus obtaining an aqueous flame retardant composition (B) in the form of a suspension.

[0156] An aqueous resin solution (A) having a melamine content of about 16% and solids (a A ) of 65% was prepared by mixing melamine (Melameen® 390 - BASF) 17.9 parts by weight with deionized water 23.1 parts by weight. An aqueous resin solution (A) having a melamine content of about 16% and solids (a A ) of 65% was prepared by mixing melamine (Melameen® 390 - BASF) 17.9 parts by weight with deionized water 23.1 parts by weight. A 60% aqueous solution of melamine (Melameen® 390 - BASF) 29.8 parts by weight was then added while stirring the mixture.

[0157] An aqueous intumescent composition (C) was prepared by mixing the aqueous flame retardant composition (B) into the aqueous resin solution (A) in an amount to achieve a mass ratio (a A ):((b)+(c)) (ratio of solids deriving from the aqueous resin solution (A) to flame-retardant ingredients deriving from the aqueous flame retardant composition (B)) of 1 : 1.3, under stirring.

[0158]

[0159] Testing of aqueous intumescent composition (C)

[0160] Direct coating

[0161] Examples 6 to 12

[0162] The aqueous intumescent composition (C) prepared according to one of examples 1 to 5 was applied on a substrate having dimensions of 15.5 cm x 30 cm using a brush in the amounts shown in Table 2. The coated substrate was placed in a drying oven at 80°C for 10 minutes. Fire resistance tests were performed on the treated substrate according to the standard UNI 9174 (2010).

[0163] Comparative example 2

[0164] The aqueous intumescent composition (C) prepared according to comparative example 1 was applied on a substrate having dimensions of 15.5 cm x 30 cm using a brush in the amounts shown in Table 2. The coated substrate was placed in a drying oven at 80°C for 10 minutes. Fire resistance tests were performed on the treated substrate according to the standard UNI 9174 (2010).

[0165]

[0166] Indirect coating

[0167] Preparation of Expandable Carriers

[0168] 65 parts by weight of melamine with a content of 55% 650 is mixed with 35 parts by weight of deionized water to obtain a resin aqueous solution.

[0169] Soda-soaked kraft paper was passed through an aqueous resin solution to impregnate the paper with the resin solution. Excess resin solution was removed from the surface of the impregnated kraft paper using a scraper. Subsequently, the water-swellable composition (C1) prepared according to Example 1 was applied to one side of the impregnated kraft paper using a brush, and the treated kraft paper was dried in a drying oven at 80°C to reduce the moisture content of the treated kraft paper to 6-7%. The moisture content was assessed using an infrared moisture analyzer (Sartorius MA35; 80°C, 16 minutes).

[0170] Using this method, a combined amount of supported acid donor (b) and carbon donor (c) of 40 g / m was prepared. 2 The combined amount of the first-treated kraft paper (TKP1), the supporting acid donor (b), and the carbon donor (c) is 60 g / m³. 2 The combined amount of the second-treated kraft paper (TKP2) and the supporting acid donor (b) and carbon donor (c) is 80 g / m. 2 The third-processed kraft paper (TKP3).

[0171] Testing of expandable carriers

[0172] Example 13

[0173] By using a sheet of ordinary pre-impregnated decorative paper (200g / m²) 2 The components include: a first expanded carrier (TKP1) with its bearing side facing the decorative paper; a second expanded carrier (TKP2) with its bearing side facing the first expanded carrier; a substrate (PB); a third expanded carrier (TKP2) with its bearing side facing away from the substrate; a fourth expanded carrier (TKP1) with its bearing side facing away from the third expanded carrier; and ordinary prepreg decorative paper (200g / m²). 2 The assembled components are stacked sequentially and pressed through a press (Bürkle Laborpresse) to produce a treated decorative panel. The treated product is then tested for fire resistance according to standard UNI 9174 (2010).

[0174] Example 14

[0175] By using a sheet of ordinary pre-impregnated decorative paper (200g / m²) 2), a first intumescent carrier facing the decorative paper on the intumescent load side (TKP1 ), a second intumescent carrier facing the first intumescent carrier on the intumescent load side (TKP3), a substrate (PB), a third intumescent carrier facing away from the substrate on the intumescent load side (TKP3), a fourth intumescent carrier facing away from the third intumescent carrier on the intumescent load side (TKP1 ) and a common pre-impregnated decorative paper (200 g / m 2 ) were stacked in sequence and the assembled elements were passed through a press (Bürkle Laborpresse) to produce a treated decorative panel. Fire resistance tests were carried out on the treated product according to the standard UNI 9174 (2010).

[0176] Example 15

[0177] A treated decorative panel was prepared by stacking in sequence one common pre- impregnated decorative paper (200 g / m 2 ), a first intumescent carrier facing the decorative paper on the intumescent load side (TKP2), a second intumescent carrier facing the first intumescent carrier on the intumescent load side (TKP2), a substrate (CB), a third intumescent carrier facing away from the substrate on the intumescent load side (TKP2), a fourth intumescent carrier facing away from the third intumescent carrier on the intumescent load side (TKP2) and a common pre-impregnated decorative paper (200 g / m 2 ), and passing the assembled elements through a press (Bürkle Laborpresse). Fire resistance tests were carried out on the treated product according to the standard UNI 9174 (2010).

[0178] Example 16

[0179] A treated decorative panel was prepared by stacking in sequence one common pre- impregnated decorative paper (200 g / m 2 ), a first intumescent carrier facing the decorative paper on the intumescent load side (TKP3), a substrate (MDF), a second intumescent carrier facing away from the substrate on the intumescent load side (TKP3) and a common pre-impregnated decorative paper (200 g / m 2 ), and passing the assembled elements through a press (Bürkle Laborpresse). Fire resistance tests were carried out on the treated product according to the standard UNI 9174 (2010).

[0180]

[0181] Test results

[0182] When testing the flame retardancy of the samples according to the UNI 9174 test conditions, a flame spread value of no more than 200 mm generally gives a rating of "Class 1 ", which is the highest rating that can be achieved when tested according to UNI 9174.

[0183] The inventors' experience is that samples that perform well under UNI 9174 test conditions will generally also perform well under DIN EN 13823 (SBI) test conditions, and a correlation can be established between the results of the two tests. A flame height over the first 2 minutes under UNI 9174 test conditions of < 10 cm above the frame height of the sample holder generally indicates a fairly good fire resistance, and is generally correlated to the FIGRA value under DIN EN 13823 test conditions required for classification as Euroclass B. Furthermore, a flame spread over the first 2 minutes of > 200 mm and / or a flame height over the frame height of the sample holder of > 12 cm generally indicates thresholds of THR and / or FIGRA that will be exceeded for classification as Euroclass B.

[0184] To confirm the above correlation, the treated substrates were prepared in the manner described in Example 6, and then tested according to standard DIN EN 13823 (2015) (SBI test). The test results were as follows:

[0185] FIGRA 0.2 MJ: 11 W / s

[0186] THR (600 s): 1.5 MJ

[0187] TSP (600 s): 61.5 m 2

[0188] SMOGRA: 4 m 2 / s 2

[0189] Smoke density corrected Bsl dO (Euroclass B)

[0190] Based on the correlation between the results of the tests under UNI 9174 test conditions and the tests under DIN EN 13823 test conditions, it can be predicted with high certainty that the fire resistance of the treated products obtained in Examples 13-15 will also meet the requirements for classification as Euroclass B, and that the fire resistance of the treated product obtained in Example 16 will be at the border between the properties for classification as Euroclass B and the properties for classification as Euroclass C, both of which describe conditions of low flammability.

[0191] In addition to the experiments described in detail above, further experiments were carried out in which different coating amounts were applied to the substrates (by direct coating as well as indirect coating). When evaluating the fire resistance of the treated substrates, it was found that when the substrates were coated directly, the use of 80-110 g / m 2of 100-120 g / m2of total coating amount usually enables a classification according to DIN EN 13823 (2015) of Euroclass B, and when the substrate is indirectly coated, using 100-120 g / m2of total coating amount usually enables a classification according to DIN EN 13823 (2015) of Euroclass B1. 2 of 100-120 g / m2of total coating amount usually enables a classification according to DIN EN 13823 (2015) of Euroclass B. The coating amounts mentioned refer to the amount coated on any given side of the substrate (applied as one or more layers).

[0192] Experiments with commercially available aqueous solutions of resins, such as The results of these experiments were in line with the results obtained with the powder type resin ingredients.

Claims

1. A method for imparting flame retardancy to wood or cellulosic materials, said materials being usable in the production of furniture, interior building structures, or decorative interiors, said method comprising the steps (1) and (2): (1) An acid donor (b) and a carbon donor (c) are introduced into an aqueous resin solution (A) to obtain an aqueous swellable composition (C), wherein... The resin aqueous solution (A) is selected from the group consisting of melamine-formaldehyde resin aqueous solution, melamine-urea-formaldehyde resin aqueous solution, mixtures thereof, and mixtures thereof with urea-formaldehyde resin aqueous solution and / or phenolic resin aqueous solution; wherein The resin aqueous solution (A) shows a total melamine content of 20 to 45% by weight relative to the total weight of the resin aqueous solution (A); The acid donor (b) is selected from the group consisting of ammonium polyphosphate, amidourea phosphate, guanidine phosphate, and mixtures thereof; The carbon donor (c) is selected from the group consisting of glucose, arabinose and other monosaccharides, lactose, maltose and other disaccharides, starch, cellulose, dextrin and other polysaccharides, sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol or other polyols and mixtures thereof; The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) introduced into the resin aqueous solution (A) is 10:1 to 1:1; and The amounts of the acid donor (b) and the carbon donor (c) introduced into the resin aqueous solution (A) are such that the solids (a) of the resin aqueous solution (A) as determined according to DIN 53216 are... A The mass ratio of (a) to the total amount of acid donor (b) and carbon donor (c) (a) A The ratio of (b) to (c) is 0.25:1 to 5:

1. Relative to the total weight of the aqueous swelling composition (C), the aqueous swelling composition (C) exhibits 50 to 80% by weight of solids (a C ); (2) Step (2B) of laminating one or more layers of expanded carrier and decorative paper onto the wood or cellulosic material in a specified order. in, The expandable carrier comprises a pad made of glass or other fibers that has been coated with the water-swellable composition (C).

2. The method as described in claim 1, wherein, The resin aqueous solution (A) shows a total melamine content of 25 to 35% by weight relative to the total weight of the resin aqueous solution (A).

3. The method as described in claim 1, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) introduced into the resin aqueous solution (A) is 8:1 to 1:

1.

4. The method of claim 1, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) introduced into the resin aqueous solution (A) is 6:1 to 1:

1.

5. The method of claim 1, wherein, The amounts of the acid donor (b) and the carbon donor (c) introduced into the resin aqueous solution (A) are such that the solids (a) of the resin aqueous solution (A) as determined according to DIN 53216 are... A The mass ratio of (a) to the total amount of acid donor (b) and carbon donor (c) (a) A The ratio of (b) to (c) is 0.30:1 to 2.5:

1.

6. The method of claim 1, wherein, The aqueous swelling composition (C) exhibits 60 to 75% by weight of solids relative to the total weight of the composition (C). C ).

7. The method according to any one of claims 1 to 6, wherein, The acid donor (b) and the carbon donor (c) are introduced as particulate powders into the resin aqueous solution (A).

8. The method of claim 7, wherein, The solids content (a) of the water-swellable composition (C) is adjusted by adding water. C Thus, the total weight relative to the water-swellable composition (C) is 50 to 80% by weight.

9. The method according to any one of claims 1 to 6, wherein, Before introducing the acid donor (b) and the carbon donor (c) into the resin aqueous solution (A), the acid donor (b) and the carbon donor (c) are dispersed or suspended in water to form an aqueous flame retardant composition (B) comprising a total of 40 to 80% by weight of the acid donor (b) and the carbon donor (c) relative to the total weight of the aqueous flame retardant composition (B).

10. The method according to any one of claims 1 to 6, wherein, Before introducing the acid donor (b) and the carbon donor (c) into the resin aqueous solution (A), the acid donor (b) and the carbon donor (c) are dispersed or suspended in water to form an aqueous flame retardant composition (B) comprising a total of 45 to 75% by weight of the acid donor (b) and the carbon donor (c) relative to the total weight of the aqueous flame retardant composition (B).

11. The method according to any one of claims 1 to 6, wherein, Before introducing the acid donor (b) and the carbon donor (c) into the resin aqueous solution (A), the acid donor (b) and the carbon donor (c) are dispersed or suspended in water to form an aqueous flame retardant composition (B) comprising a total of 55 to 70% by weight of the acid donor (b) and the carbon donor (c) relative to the total weight of the aqueous flame retardant composition (B).

12. The method according to any one of claims 1 to 6, wherein, The total amount of acid donor (b) and carbon donor (c) coated on the expanded support is 30 to 200 g / m³. 2 .

13. The method according to any one of claims 1 to 6, wherein, The total amount of acid donor (b) and carbon donor (c) coated on the expanded support is 40 to 150 g / m³. 2 .

14. The method according to any one of claims 1 to 6, wherein, The total amount of acid donor (b) and carbon donor (c) coated on the expanded support is 60 to 120 g / m³. 2 .

15. The method according to any one of claims 1 to 6, wherein, The resin aqueous solution (A) comprises a mixture of a melamine-formaldehyde resin aqueous solution and a phenolic resin aqueous solution, wherein the solids (a) derived from the melamine-formaldehyde resin aqueous solution MF ) and solids derived from the aqueous solution of the phenolic resin (a PF The mass ratio of ) is 2:1 to 10:

1.

16. The method according to any one of claims 1 to 6, wherein, The resin aqueous solution (A) comprises a mixture of a melamine-formaldehyde resin aqueous solution and a phenolic resin aqueous solution, wherein the solids (a) derived from the melamine-formaldehyde resin aqueous solution MF ) and solids derived from the aqueous solution of the phenolic resin (a PF The mass ratio of ) is 3:1 to 9:

1.

17. The method according to any one of claims 1 to 6, wherein, The resin aqueous solution (A) comprises a mixture of a melamine-formaldehyde resin aqueous solution and a phenolic resin aqueous solution, wherein the solids (a) derived from the melamine-formaldehyde resin aqueous solution MF ) and solids derived from the aqueous solution of the phenolic resin (a PF The mass ratio of ) is 4:1 to 8:

1.

18. The method according to any one of claims 1 to 6, wherein, The acid donor (b) is selected from the group consisting of ammonium polyphosphate and guanidine phosphate.

19. The method according to any one of claims 1 to 6, wherein, The carbon donor (c) is selected from the group consisting of starch, cellulose, dextrin and other polysaccharides, sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol or other polyols and mixtures thereof.

20. The method according to any one of claims 1 to 6, wherein, The carbon donor (c) is selected from the group consisting of sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol, and mixtures thereof.

21. The method according to any one of claims 1 to 6, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) is 6:1 to 2:

1.

22. The method according to any one of claims 1 to 6, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) is 5:1 to 3:

1.

23. The method according to any one of claims 1 to 6, wherein, The resin aqueous solution (A) exhibits 45 to 75% by weight of solids relative to the total weight of the resin aqueous solution (A). A ).

24. The method according to any one of claims 1 to 6, wherein, The resin aqueous solution (A) exhibits 50 to 70% by weight of solids relative to the total weight of the resin aqueous solution (A). A ).

25. The method according to any one of claims 1 to 6, wherein, The resin aqueous solution (A) exhibits 55 to 65% by weight of solids relative to the total weight of the resin aqueous solution (A). A ).

26. The method according to any one of claims 1 to 6, wherein, The wood-based materials are selected from the group consisting of timber, lumber, and engineered wood.

27. The method according to any one of claims 1 to 6, wherein, The expandable carrier comprises a pad made of glass or other fibers that has been pre-impregnated with an adhesive resin.

28. The method according to any one of claims 1 to 6, wherein, In step (2B), the expanded carrier and the decorative paper are laminated onto one or both sides of the HPL or wood panel.

29. The method according to any one of claims 1 to 6, wherein, The water-swellable composition (C) and / or the water-swellable flame retardant composition (B) further comprise 0.5 to 10% by weight of a functional compound relative to the total weight of the acid donor (b) and the carbon donor (c), the functional compound being selected from the group consisting of aluminosilicates, calcium and magnesium silicates, silicon dioxide, titanium dioxide, aluminum hydroxide, calcium and magnesium phosphates, and mixtures thereof.

30. The method of claim 29, wherein, The water-swellable composition (C) and / or the water-swellable flame retardant composition (B) further comprise 1 to 5% by weight of the functional compound relative to the total weight of the acid donor (b) and the carbon donor (c).

31. The method according to any one of claims 1 to 6, wherein, Relative to the total weight of the water-swellable composition (C), the water-swellable composition (C) further comprises no more than 5% by weight of additive (d), said additive (d) being selected from the group consisting of melamine, urea, curing agent, flow agent, defoamer and dye.

32. A water-swellable composition (C) comprising: The resin aqueous solution (A) is selected from the group consisting of melamine-formaldehyde resin aqueous solution, melamine-urea-formaldehyde resin aqueous solution, mixtures thereof, and mixtures thereof with urea-formaldehyde resin aqueous solution and / or phenolic resin aqueous solution. Acid donor (b) is selected from the group consisting of ammonium polyphosphate, urea phosphate, amidourea phosphate, guanidine phosphate, and mixtures thereof; and Carbon donor (c) is selected from the group consisting of glucose, arabinose and other monosaccharides, lactose, maltose and other disaccharides, starch, cellulose, dextrin and other polysaccharides, sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol, other polyols, and mixtures thereof; wherein The resin aqueous solution (A) shows a total melamine content of 20 to 45% by weight relative to the total weight of the resin aqueous solution (A); The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) is 10:1 to 1:1; and The amounts of the acid donor (b) and the carbon donor (c) contained are such that the solids (a) of the resin aqueous solution (A) as determined according to DIN 53216 A The mass ratio of (a) to the total amount of acid donor (b) and carbon donor (c) (a) A The ratio of (b) to (c) is 0.25:1 to 5:

1. Relative to the total weight of the aqueous swelling composition (C), the aqueous swelling composition (C) shows 50 to 80% by weight of solids (a) as determined according to DIN 53216. C ).

33. The water-swellable composition (C) as described in claim 32, wherein, The resin aqueous solution (A) is a mixture of melamine-formaldehyde resin aqueous solution and phenolic resin aqueous solution, wherein the solids (a) derived from the melamine-formaldehyde resin aqueous solution MF ) and solids derived from the aqueous solution of the phenolic resin (a PF The mass ratio of ) is 2:1 to 10:

1.

34. The water-swellable composition (C) as described in claim 33, wherein, Solids derived from the melamine-formaldehyde resin aqueous solution (a MF ) and solids derived from the aqueous solution of the phenolic resin (a PF The mass ratio of ) is 3:1 to 9:

1.

35. The water-swellable composition (C) as described in claim 33, wherein, Solids derived from the melamine-formaldehyde resin aqueous solution (a MF ) and solids derived from the aqueous solution of the phenolic resin (a PF The mass ratio of ) is 4:1 to 8:

1.

36. The water-swellable composition (C) as described in claim 32, wherein, The acid donor (b) is ammonium polyphosphate or guanidine phosphate.

37. The water-swellable composition (C) as described in claim 32, wherein, The carbon donor (c) is selected from the group consisting of starch, cellulose, dextrin and other polysaccharides, sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol, other polyols and mixtures thereof.

38. The water-swellable composition (C) as described in claim 32, wherein, The carbon donor (c) is selected from the group consisting of sorbitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, mannitol, and mixtures thereof.

39. The water-swellable composition (C) as described in claim 32, wherein, The resin aqueous solution (A) shows a total melamine content of 25 to 35% by weight relative to the total weight of the resin aqueous solution (A).

40. The water-swellable composition (C) according to claim 32, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) is 8:1 to 1:

1.

41. The water-swellable composition (C) according to claim 32, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) is 6:1 to 1:

1.

42. The water-swellable composition (C) according to claim 32, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) is 6:1 to 2:

1.

43. The water-swellable composition (C) as described in claim 32, wherein, The mass ratio (b):(c) of the acid donor (b) to the carbon donor (c) is 5:1 to 3:

1.

44. The water-swellable composition (C) as described in claim 32, wherein, The amounts of the acid donor (b) and the carbon donor (c) contained are such that the solids (a) of the resin aqueous solution (A) as determined according to DIN 53216 A The mass ratio of (a) to the total amount of acid donor (b) and carbon donor (c) (a) A The ratio of (b) to (c) is 0.30:1 to 2.5:

1.

45. The water-swellable composition (C) as described in claim 32, wherein, Relative to the total weight of the aqueous swelling composition (C), the aqueous swelling composition (C) shows 60 to 75% by weight of solids (a) as determined according to DIN 53216. C ).

46. ​​The water-swellable composition (C) according to any one of claims 32 to 45, wherein, The resin aqueous solution (A) exhibits 45 to 75% by weight of solids relative to the total weight of the resin aqueous solution (A). A ).

47. The water-swellable composition (C) according to any one of claims 32 to 45, wherein, The resin aqueous solution (A) exhibits 50 to 70% by weight of solids relative to the total weight of the resin aqueous solution (A). A ).

48. The water-swellable composition (C) according to any one of claims 32 to 45, wherein, The resin aqueous solution (A) exhibits 55 to 65% by weight of solids relative to the total weight of the resin aqueous solution (A). A ).

49. The water-swellable composition (C) according to any one of claims 32 to 45, wherein, Relative to the total weight of the water-swellable composition (C), the water-swellable composition (C) further comprises no more than 5% by weight of additive (d), said additive (d) being selected from the group consisting of melamine, urea, curing agent, flow agent, defoamer and dye.

50. The water-swellable composition (C) according to any one of claims 32 to 45, wherein, The composition is halogen-free.

51. An intumescent carrier comprising a pad made of glass or other fibers, said pad having been coated with the water-containing intumescent composition (C) according to any one of claims 32 to 50.

52. The expandable carrier as described in claim 51, wherein, The amount of the water-swellable composition (C) coated onto the mat made of glass or other fibers, based on the total amount of acid donor (b) and carbon donor (c), is 30 to 200 g / m². 2 .

53. The expandable carrier as described in claim 51, wherein, The amount of the water-swellable composition (C) coated onto the mat made of glass or other fibers, based on the total amount of acid donor (b) and carbon donor (c), is 40 to 150 g / m². 2 .

54. The expandable carrier as described in claim 51, wherein, The amount of the water-swellable composition (C) coated onto the mat made of glass or other fibers, based on the total amount of acid donor (b) and carbon donor (c), is 60 to 120 g / m². 2 .

55. The expandable carrier according to any one of claims 51 to 54, wherein, The mat, made of glass or other fibers, has been pre-impregnated with adhesive resin.

56. A flame-retardant product comprising a wood or natural fiber board or panel, wherein the board or panel has been laminated with an intumescent carrier and decorative paper as described in any one of claims 51 to 55.

57. The flame-retardant product as described in claim 56, wherein, The wood-based or natural fiber-based boards or panels are selected from the group consisting of timber, lumber, and engineered wood.

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