Composition for coating and sealing the edges of wood fibre boards

Abstract

A composition for sealing/coating the edges of wood-fibre boards is provided. The composition includes at least one compound of general formula R.sup.1.sub.aSiX.sub.(4-a) (I), and/or their hydrolysis products. X is H, OH or a hydrolyzable group selected from alkoxy-, aryloxy-, and acyloxy-, R.sup.1 is an organic radical selected from the group including alkyl, aryl, and cycloalkyl, and R.sup.1 has at least one functional group Q.sub.1 selected from a hydroxy, amino, monoalkylamino, carboxy, mercapto, alkoxy, aldehyde, acrylic, acryloxy, methacrylic, methacryloxy, cyano, isocyano and epoxy group, and a=0, 1, 2, 3, The composition also includes at least one compound of general formula R.sup.2.sub.bSiX.sub.(4-b) (II), and/or their hydrolysis products. X has the above meaning, R.sup.2 is a non-hydrolyzable organic radical selected from alkyl, aryl, alkenyl, alkynyl, cycloalkyl, and cycloalkenyl, and b=1, 2, 3, or 4. The composition also includes at least one aqueous polymer dispersion.

Claims

1. A composition for sealing/coating the edges of wood-fibre boards, obtained from at least one compound of general formula (I)
SiX.sub.4(I), wherein X is alkoxy, and at least three compounds of general formula (II)
R.sub.2SiX.sub.3(II), wherein X is alkoxy, R.sup.2 is a C1-C10 alkyl moiety or a C6-C10 aryl moiety, wherein the ratio of the at least one compound of general formula (I) to the at least three compounds of general formula (II) is between 1:0.5 and 1:2; at least one aqueous polymer dispersion, wherein the at least one polymer is selected from the group comprising polyurethanes, epoxy resins, melamine resins, and/or polyacrylates; and inorganic particles selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2, and mixtures thereof, wherein the inorganic particles comprise 0.1 to 10% by weight of the composition based upon the total weight of the composition.

2. The composition according to claim 1, wherein each X is independently selected from C.sub.1-6-alkoxy.

3. The composition according to claim 2, wherein the C.sub.1-6-alkoxy comprises methoxy, ethoxy, n-propoxy or butoxy.

4. The composition according to claim 1, wherein non-hydrolyzable organic R.sup.2 is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, cyclohexyl, phenyl and naphthyl.

5. The composition according to claim 1, wherein the compound of general formula (I) is contained in a molar amount between 0.08-0.2 mol, and the compound of general formula (II) is contained in a molar amount between 0.05 and 0.1.

6. The composition according to claim 1, wherein the at least one polymer is selected from the group comprising polyurethanes.

7. A method for preparing a composition according to claim 1 comprising the steps of providing at least one compound of general formula (I) and at least three compounds of formula (II) optionally adding at least one dispersion of inorganic particles; adding at least one catalyst to the mixture of at least one compound of formula (I) and at least three compounds of formula (II); separating the aqueous phase of the reaction mixture of at least one compound of formula (I) and at least three compounds of formula (II), and adding at least one polymer to the separated aqueous reaction mixture of at least one compound of formula (I) and at least three compounds of formula (II).

8. A fibre board, comprising the composition according to claim 1 applied to the edges of the fibre board.

9. The composition according to claim 1, wherein the alkoxy comprises methoxy, ethoxy, n-propoxy, or i-propoxy.

10. The composition according to claim 1, wherein the inorganic particles are present in an amount from 5 to 20 weight percent, based on the solids content of the at least one compound of general formula (I) and the at least three compounds of general formula (II).

11. A wooden fibre board comprising edges, wherein the edges are coated with at least one composition obtained from at least one compound of general formula (I)
SiX.sub.4(I), wherein X is alkoxy, and at least three compounds of general formula (II)
R.sup.2SiX.sub.3(II), wherein X is alkoxy, R.sup.2 is a C1-C10 alkyl moiety or a C6-C10 aryl moiety, wherein the ratio of the at least one compound of general formula (I) to the at least three compounds of general formula (II) is between 1:0.5 and 1:2; at least one aqueous polymer dispersion, wherein the at least one polymer is selected from the group comprising polyurethanes, epoxy resins, melamine resins, and/or polyacrylates; and inorganic particles selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2, and mixtures thereof, wherein the inorganic particles comprise 0.1 to 10% by weight of the composition based upon the total weight of the composition.

12. The wooden fibre board according to claim 11, wherein the board is a high density fibre (HDF) board or a medium density fibre (MDF).

13. The wooden fibre board according to claim 11, wherein the layer thickness of the composition on the board edges is 10 m to 50 m.

14. A method for coating and/or sealing the edges of a wood fiber board comprising: applying a composition to the edges of the wood fibre board by spraying, rolling, or using vacuum, the composition obtained from at least one compound of general formula (I)
SiX.sub.4(I), wherein X is alkoxy, and at least three compounds of general formula (II)
R.sup.2SiX.sub.3(II), wherein X is alkoxy, R.sup.2 is a C1-C10 alkyl moiety or a C6-C10 aryl moiety, wherein the ratio of the at least one compound of general formula (I) to the at least three compounds of general formula (II) is between 1:0.5 and 1:2; at least one aqueous polymer dispersion, wherein the at least one polymer is selected from the group comprising polyurethanes, epoxy resins, melamine resins, and/or polyacrylates; and inorganic particles selected from the group consisting of SiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2, TiO.sub.2, and mixtures thereof, wherein the inorganic particles comprise 0.1 to 10% by weight of the composition based upon the total weight of the composition.

15. The method according to claim 14, wherein the wood fibre board is a high density fibre (HDF) board, a medium density fibre (MDF) board, or a wood plastic composite (WPC) board.

16. The method according to claim 15, wherein the composition is applied in liquid form to the edges of the wood fibre board in a quantity of 100 silane fl. g/m.sup.2 to 200 silane fl. g/m.sup.2 resulting in a solid content on the panel edge of 5 mg/cm.sup.2 to 25 mg/cm.sup.2.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The solution is explained in more detail below with reference to the examples.

Example 1: Preparation of a Sealant Composition

(2) 12.3 g Ocytltriethoxysilane, 2.4 g trimethylsilane, 6.1 g phenyltriethoxysilane, 20.8 g tetraethoxysilane and 28.8 g of an aqueous SiO.sub.2 dispersion (50% by weight) from Fa. Obermaier are added, heated to 80 C. and stirred, 3.6 g para toluenic acid is now added to water (30% by weight) while stirring and stirred for 120 minutes. After another 24 hours the pH value is raised to a pH value of 7 by adding a 25% ammonia solution (in the above example 6.2 g) while stirring.

(3) After a further stirring time of 2 hours, 80 g of water is now added, stirred again for 30 minutes and then the suspension is stored for 4 hours without stirring.

(4) After this waiting time, the aqueous phase with the binder portion separates from the ethanolic phase. The aqueous phase is now separated by a separating funnel. Thus, the inorganic aqueous coating system is obtained.

(5) 50 g of this coating system (solid: 52%) is now mixed with 20 g of an aqueous polyurethane solution (Fa. Alberdingk U 3251, solid: 35%).

(6) The coating system can now be applied to an edge with a foam roller or pipette and thermally cured (e.g. 100 C., 5 minutes).

Example 2: HDF with UF Glue and Prepolymer

(7) A 7.4 mm HDF with a density of approx. 850 kg/m.sup.3 is cast in a casting machine with a prepolymer in a quantity of 1.2 kg/m.sup.2. The board is transferred to a vacuum station and the prepolymer is sucked into the HDF by means of vacuum. The boards are then stored for three days, then coated in a KT press with melamine resin impregnated papers (overlay, decor and backing) under pressure and temperature (p=40 bar, T=200 C., t=15 sec).

(8) The boards are transferred to a ripening warehouse for cooling and after three days are cut into planks on a flooring line. They are then provided with tongue and groove, and then the profiles are sprayed in a continuous flow with the composition of example 1 (application quantity: 100 g fl./m.sup.2, solids content: approx. 42%). The silane was dried with an IR radiator. For comparison, a board was cut into planks without edge sealing.

Example 3: MDF with PMDI Glue

(9) HDF boards were produced on an MDF line using a PMDI binder. A gluing factor of 8% and a bulk density of 850 kg/m.sup.3 was used. The HDF was cooled and sanded after the press. The boards were then stored for three days, then coated in a KT press with melamine resin impregnated papers (overlay, decor and backing) under pressure and temperature (p=40 bar, T=200 C., t=15 sec).

(10) The boards are transferred to a ripening warehouse for cooling and after three days are cut into planks on a flooring line. They are then provided with tongue and groove, and then the profiles are sprayed in a continuous flow with the composition of example 1 (application quantity: 100 g fl./m.sup.2, solids content: approx. 42%). The silane was dried with an IR radiator. For comparison, a board was cut into planks without edge sealing.

Example 4: HDF with MUF Glue

(11) HDF boards were produced on an MDF line with a MUF binder. A gluing factor of 25%, a melamine reinforcement of 24% and a bulk density of 850 kg/m.sup.3 were used. The HDF was cooled and sanded after the press. The boards were then stored for three days, then coated in a KT press with melamine resin impregnated papers (overlay, decor and backing) under pressure and temperature (p=40 bar, T=200 C., t=15 sec).

(12) The boards are transferred to a ripening warehouse for cooling and after three days are cut into planks on a flooring line. They are then provided with tongue and groove, and then the profiles are sprayed in a continuous flow with the composition of example 1 (application quantity: 100 g fl./m.sup.2, solids content: approx. 42%). The silane was dried with an IR radiator. For comparison, a board was cut into planks without edge sealing.

Example 5: Edge Swell Test

(13) For the edge swelling test, twotwo samples were cut from each of the coated boards (15050 mmthickness). Half of the samples were then sealed at the cut edges with the composition of example 1, whereby the application quantity was always approx. 100 g/m.sup.2. Then the edge swelling test was carried out according to ISO 24336:2005.

(14) The swelling is determined according to DIN EN 13329:2016 or ISO 24336: 2005 using the so-called edge swelling test. In this test, a coated sample without profile (15050 mm) is vertically immersed 50 mm into a water bath (20 C.) and then the edge swelling is determined at three points in the immersed area after 24 h. The results are summarized in the following table.

(15) TABLE-US-00001 Reduction Edges- compared Thick- source to zero Exam- ness in sample ple Sample description.sup.* in mm % in %. Zero sample UF glue.sup.** 7.4 16.2 Zero sample UF glue + 7.4 8.1 50.0 edge sealing 2 HDF UF glue with 7.4 5.25 prepolymer 2 HDF UF glue with 7.4 2.3 56.2 prepolymer + edge sealant 3 HDF with PMDI.sup.*** 7.4 9.7 3 HDF with PMDI + 7.4 6.6 32 Edge sealing 4 HDF with MUF glue.sup.**** 7.4 8.1 4 HDF with MUF glue + 7.4 2.6 68 Edge sealing WPC with glued-on 4.5 11.0 PP film.sup.***** WPC with glued-on PP 4.5 5.9 46.4 film + edge sealing HDF UF glue with PVC film 9.0 9.9 HDF UF glue with PVC 9.0 4.8 51.5 film + edge sealing.sup.**** .sup.* The silane-based edge sealant was applied in a quantity of approx. 100 g fl. /m.sup.2. .sup.** The HDF had a density of approx. 850 kg/m.sup.3 and was coated with a standard Floor construction (overlay, decor and backing). .sup.*** The HDF had a bulk density of 850 kg/m.sup.3 and a gluing of approx. 8% related to fibres and was coated with a standard Floor construction (overlay, decor and backing). .sup.**** The HDF had a density of approx. 850 kg/m.sup.3 and a gluing of 25% of a with 24% melamine-reinforced UF glue and was coated with a standard Floor construction (overlay, decor and backing). .sup.***** The WPC consisted of approx. 50% by weight PET fibres and approx. 50% by weight Wood fibres. A 0.4 mm thick PET film was glued to the board with the help of a PU Hotmelts. .sup.****** The HDF had a bulk density of 850 kg/m3. A 0.5 mm thick PVC film is glued onto it with the help of a PU-Hotmelts.

(16) As can be seen from the table, a reduction in edge swelling is more or less clearly possible, regardless of the glue system used and the panel composition. This sealing system can therefore be used for a wide range of different panel types.