Impregnate with antistatic properties

Abstract

An impregnate with antistatic properties for use in laminates or for coating wood-based panels is disclosed. A resin used for impregnating and/or coating paper may include carbon-based particles, at least one compound of the general formula (Ia) R.sup.1.sub.aSiX.sub.(4-a), R.sup.3.sub.cSiX.sub.(4-c) (II), and inorganic particles. X is methoxy, ethoxy, n-propoxy or i-propoxy. R.sup.1 is an organic radical selected from the group including methyl, ethyl, propyl, or vinyl, and has at least one functional group Q.sub.1, selected from the group including acrylic, acryloxy, methacrylic, methacyloxy, or epoxy. R.sup.3 is a non-hydrolyzable organic radical selected from the group including C1-C10 alky, C6-10 aryl, wherein C is 1, 2, or 3, and the inorganic particles have a size between 2 nm and 400 nm.

Claims

1. An impregnate with an impregnated paper layer with antistatic properties for use in laminates or for coating wood-based panels, wherein at least one resin used to impregnate and/or coat a paper comprises: carbon-based particles, wherein a surface of the carbon-based particles comprises: at least one compound having the general formula (Ia)
R.sup.1.sub.aSiX.sub.(4-a)  (Ia), wherein X is methoxy, ethoxy, n-propoxy or i-propoxy, wherein R.sup.1 is an organic radical selected from the group consisting of methyl, ethyl, propyl or vinyl, and R.sup.1 has at least one functional group Q.sub.1 selected from a group consisting of an acrylic, acryloxy, methacrylic, methacryloxy, and epoxy group, and, wherein a is 1 or 2; at least one further compound of the general formula (II)
R.sup.3.sub.cSiX.sub.(4-c)  (II), wherein X is methoxy, ethoxy, n-propoxy or i-propoxy, wherein R.sup.3 is a non-hydrolyzable organic radical R.sup.3 selected from the group consisting of C1-C10 alkyl, C6-C10 aryl, and wherein c is 1, 2 or 3; and, inorganic particles with a size in the range of 2 nm to 400 nm.

2. The impregnate according to claim 1, wherein the carbon-based particles comprise at least one of carbon nanotubes (CNTs) or graphene.

3. The impregnate according to claim 1, wherein the inorganic particles have a size in the range of 2 nm to 100 nm.

4. The impregnate according to claim 1, wherein the inorganic particles have a size in the range of 2 nm to 50 nm.

5. The impregnate according to claim 1, wherein the inorganic particles comprise at least one of SiO.sub.2, AlO.sub.23, ZrO.sub.2, or TiO.sub.2 particles.

6. The impregnate according to claim 1, wherein the molar ratio of the silane compound of formula (Ia) to the silane compounds of formula (II) is between 1:0.5 and 1:2.

7. The impregnate according to claim 1, wherein the inorganic particles are used in a quantity range of 0.1 to 25% by weight, based on the solids content of the silane.

8. The impregnate according to claim 7, wherein the molar ratio of the silane compound of formula (Ia) to the silane compounds of formula (II) is between 1:1 and 1.1.5.

9. The impregnate according to claim 1, wherein the at least one resin comprises carbon nanotubes, the carbon nanotubes comprising glycidyloxypropylmethyldiethoxysilane, glycidyloxypropyltriethoxysilane and octyltriethoxysilane, or a mixture thereof.

10. The impregnate according to claim 1, wherein the paper to be impregnated and/or coated with the resin is a decorative, kraft, overlay or base paper.

11. The impregnate according to claim 2, wherein the carbon nanotubes comprise a mixture of glycidyloxypropyltriethoxysilane and octyltriothoxysilane.

12. The impregnate according to claim 1, wherein the at least one resin used for impregnation and/or coating is an aqueous formaldehyde-containing resin comprising at least one of a melamine-formaldehyde resin, urea-formaldehyde resin, melamine-urea-formaldehyde resin, phenol-formaldehyde resin or a mixture thereof.

13. The impregnate according to claim 1, wherein the solids content of the resin is between 50 and 75% by weight.

14. A method of making an impregnate according to claim 1, the method comprising the steps of: providing a resin suspension comprising carbon-based particles, an at least one compound of the general formula (Ia) and at least one compound of the general formula (II); providing a paper layer, impregnating the paper layer with the resin suspension and/or coating the paper layer with the resin suspension; and drying the impregnated and/or coated paper layer.

15. A laminate comprising an at least one impregnate having antistatic properties according to claim 1.

16. The laminate according to claim 15, wherein the at least one impregnate having antistatic properties is an overlay impregnate, kraft impregnate, and/or a decorative impregnate.

17. The laminate according to claim 15, wherein, comprising an at least one further paper layer not provided with the present resin, an at least one transparent paper layer (glassine), an at least one plastic film layer, or a combination thereof.

18. The laminate according to claim 15, wherein the laminate comprises an at least one kraft impregnate with antistatic properties, an at least one transparent paper layer, an at least one decorative paper layer, and an at least one overlay paper layer.

19. A wood-based panel comprising an at least one carrier board and an at least one impregnate having antistatic properties according to claim 1 deposited on at least one side of the carrier board.

20. The wood-based panel according to claim 19, wherein the at least one impregnate with antistatic properties is a decorative impregnate.

Description

DETAILED DESCRIPTION OF THE INVENTION

Example 1: Preparation of a First Resin Suspension with Modified Carbon Particles

(1) For modification, 90 g (or 80 g) of melamine-formaldehyde resin and 8.5 g (or 17 g) of water are added, followed by 0.08 g (or 0.16 g) of para-toluenesulphonic acid. To this aqueous solution 0.7 g (or 1.4 g) of gylcidyloxypropyltriethoxysilane and 0.16 g (or 0.32 g) of ocytyltriethoxysilane are added.

(2) Then 1.5 g (or 3 g) of CNTs are dispersed in the solution using ultrasound and high shear (15 000 rpm ultraturray) and stirred at 40° C. for 30 minutes. This solution can now be processed like a normal resin system. (In parentheses are the specifications for the sample with 3% CNT in the resin)

Example 2: Preparation of a Second Resin Suspension with Modified Carbon Particles

(3) For modification, 98.5 g water is added and then 0.08 g para-toluenesulfonic acid. To this aqueous solution 0.7 g of gylcidyloxypropyltriethoxysilane and 0.16 g of ocytyltriethoxysilane are added.

(4) Subsequently, 1.5 g CNTs are dispersed in the solution using ultrasound and high shear forces (15 000 rpm ultraturray) and stirred at 40° C. for 30 minutes. This pure aqueous solution can now be dosed to melamine resin directly at the application machine.

Example 3: Production of a First Impregnate

(5) In an impregnation channel, a printed decorative paper (paper weight: 80 g/m.sup.2) is subjected to a core impregnation in the first impregnation bath. The impregnation is carried out with a standard melamine resin, which contains the usual additives (hardeners, wetting agents, defoamers, etc.) in normal quantities. The impregnating liquor had a solids content of approx. 65 wt %.

(6) To ensure that only a core impregnation was achieved, the decorative paper was sharply peeled off on both sides with a knife blade after impregnation. The resin application was approx. 80 wt % solid resin.

(7) The impregnate was dried in a floatation dryer and then coated on the back with a melamine resin in a screen unit. In addition to the usual auxiliary materials, the impregnate contained approx. 2.5% by weight carbon nanotubes from example 2. Approx. 30 g resin fl./m.sup.2 were applied.

(8) The impregnate was dried in a second air flotation dryer to a residual moisture content of approx. 6% by weight. The impregnate was cut to size and stacked.

(9) The decorative impregnate was pressed onto a large-format HDF (2.8×2.07 m, 8 mm) at approx. 200° C., 15 sec. and 40 kg/cm.sup.2 with an overlay and a backing in a KT press. Then a sample 50×50 cm was cut out of the large-format panel and conditioned for two weeks at 50% relative humidity, 23° C.

(10) Then the surface resistance was determined on the sample in accordance with DIN EN 1081: 2018. This resulted in a value of 1.0×10.sup.9Ω. A value of 5×10.sup.12Ω was found for a zero sample without carbon nanotubes

Example 4: Production of a Second Impregnate

(11) In an impregnation channel, a printed decorative paper (paper weight: 80 g/m.sup.2) is impregnated with a melamine resin in the first impregnation bath. The impregnation is carried out with a standard melamine resin in which the usual additives (hardeners, wetting agents, defoamers etc.) were contained in the normal quantities. The solids content in the resin was approx. 65 wt %. In addition, the resin contained approx. 2.5% by weight carbon nanotubes from example 2.

(12) After the squeeze rolls, approx. 140 g resin fl./m.sup.2 were still contained in the decor paper. The impregnate was dried in an air flotation dryer to a residual moisture content of approx. 6% by weight. The resin application rate was approx. 110% by weight. The impregnate was then cut to size and stacked.

(13) The decorative impregnate was pressed onto a large-format HDF (2.8×2.07 m, 8 mm) at approx. 200° C., 15 sec. and 40 kg/cm.sup.2 with an overlay and a backing in a KT press. Then a sample 50×50 cm was cut out of the large-format panel and conditioned for two weeks at 50% relative humidity, 23° C.

(14) Then the surface resistance was determined on the sample in accordance with DIN EN 1081: 2018. This resulted in a value of 8.0×10.sup.8Ω. A value of 5×10.sup.12Ω was found for a zero sample without carbon nanotubes.

Example 5: Production of a Third Impregnate

(15) A soda kraft paper (paper weight: 150 g/m.sup.2), which is to serve as the core layer for a CPL (continous produced laminate), is subjected to impregnation in an impregnation channel. An impregnating resin consisting of approx. 65% by weight of melamine resin and 35% by weight of a phenolic resin is placed in an impregnation trough. The two resins had a solids content of approx. 65 wt %. The total solids content after addition of the auxiliary materials and water was approx. 60% by weight. The resin mixture contained the usual additives (hardeners, wetting agents, defoamers, etc.) in normal quantities. In addition, the resin contained approx. 2.5 wt % carbon nanotubes from example 2.

(16) The soda kraft paper was impregnated with the impregnating resin in the impregnating trough. After the squeeze rolls, the soda kraft paper still contained approx. 215 g resin fl./m.sup.2. The impregnate was dried in an air flotation dryer to a residual moisture content of approx. 6% by weight. The resin application rate was approx. 85 wt %. The impregnate was then rolled up.

(17) The force impregnate was pressed with an overlay impregnate, a decorative impregnate and a pergament in a CPL press to form a thin laminate (T=approx. 200° C., v=15 m/min and 60 kg/cm.sup.2). Then a sample 50×50 cm was cut out of the laminate and conditioned for two weeks at 50% relative humidity, 23° C.

(18) Then the surface resistance was determined on the sample in accordance with DIN EN 1081: 2018. This resulted in a value of 6.0×10.sup.8Ω. A value of 9×10.sup.11Ω was found for a zero sample without carbon nanotubes.