TRANSPARENT OVERLAYS FOR THE PROTECTION OF INTERIOR AND EXTERIOR SURFACES
An article for indoor or outdoor use having resistance to damage from wear and tear and exposure to weather comprising: a coated overlay comprising an untreated alpha-cellulose core layer which optionally is ink-jet printed with ornamental decors or full area print designs that is saturated with a melamine formaldehyde (MF) resin and a coating layer coated on a top surface of the core layer, said coating layer comprising a polyurethane(meth)acrylate resin; a panel substrate of wood, plywood, or non-wood; a midlayer between the overlay and the substrate, said midlayer is a veneer, paper foil, or medium density overlay (MDO); a backer sheet is a bottom layer attached to a bottom surface of the substrate, wherein the backer sheet and midlayer are optional. The nonprinted regions of the coated overlay on the panel are transparent to visible light.
1 . A thermally cured article ( 7 ) for indoor or outdoor use having resistance to damage from wear and tear and exposure to weather comprising:
a coated overlay ( 1 ) comprising an untreated alpha-cellulose core layer ( 3 ) that is saturated with a melamine formaldehyde (MF) resin and a coating layer ( 2 ) coated on a top surface of the core layer ( 3 ), said coating layer ( 2 ) comprising a polyurethane(meth)acrylate resin;
a panel substrate ( 4 ) of wood, plywood, or non-wood;
a midlayer ( 5 ) between the overlay ( 1 ) and the substrate ( 4 ), said midlayer ( 5 ) is a veneer, melamine impregnated paper, paper foil, melamine formaldehyde (MF) resin impregnated paper or melamine urea formaldehyde (MUF) resin impregnated paper or medium density overlay (MDO);
a backer sheet ( 6 ) is a bottom layer attached to a bottom surface of the substrate ( 4 ),
wherein the backer sheet ( 6 ) and midlayer ( 5 ) are optional.
2 . The article ( 7 ) according to claim 1 , wherein the untreated alpha-cellulose core layer ( 3 ) is a web having a base weight of 15-80 g/m 2 .
3 . The article ( 7 ) according to claim 1 , wherein the untreated alpha-cellulose core layer ( 3 ) is saturated with a MF saturating resin to a dry weight of 80-120 g/m 2 .
4 . The article ( 7 ) according to claim 1 , wherein the coating layer ( 2 ) is applied and then is dried and cured in an amount to give a dry weight of 20-100 g/m 2 .
5 . The article ( 7 ) according to claim 1 , wherein the article comprises a backer sheet ( 6 ), or midlayer ( 5 ) or both a backer sheet ( 6 ) and midlayer ( 5 ).
6 . The article ( 7 ) according to claim 1 , wherein the coating layer ( 2 ) has at least one of the following properties:
a) Resistance to environmental impact;
b) Mechanical properties sufficient to satisfy European Standard EN438 for high pressure laminates (HPL) of >5N;
c) Impact resistance of HPL;
d) Chemical and Stain resistance that meets SEFA 3 standard; and
e) Micro scratch resistance using Martindale test method that is better than micro-corundum fortified decor paper.
7 . The article ( 7 ) according to claim 1 , wherein a surface of the coating layer ( 2 ) is chemical resistant with grade ≥4, i.e. in particular 4 or 5, measured according to EN 438-2.26: 2005, has a scratch resistance of ≥6N, measured in accordance with EN 438-2.25: 2005, and a change in the degree of gloss after exposure to weathering for 3500 hours in accordance with the EN 438-2.29: 2005 method, measured in accordance with EN ISO 2813 at an angle of of not more than 5 units.
8 . The article ( 7 ) according to claim 1 , wherein a surface of the coating layer has a change in the degree of gloss after exposure to weathering for 3500 hours in accordance with the EN 438-2.29 of not more than 20% compared to the initial value before weathering as set at 100%.
9 . The article ( 7 ) according to claim 1 , wherein the article has a weathering resistance as measured by EN 438-2.28-29:2019, to give no visible change after 3000 hours.
10 . The article ( 7 ) according to claim 1 , wherein the impregnated untreated alpha-cellulose core layer ( 3 ) is formed with a printed untreated alpha-cellulose web wherein regions that are not printed are transparent; or the impregnated untreated alpha-cellulose core layer ( 3 ) is formed with a nonprinted untreated alpha-cellulose web.
11 . The article ( 7 ) according to claim 1 , wherein the impregnated untreated alpha-cellulose core layer ( 3 ) is formed with a printed untreated alpha-cellulose web.
12 . The article ( 7 ) according to claim 1 , wherein the impregnated untreated alpha-cellulose core layer ( 3 ) is formed with a nonprinted untreated alpha-cellulose web.
13 . The article ( 7 ) according to claim 1 , wherein the untreated alpha-cellulose core layer ( 3 ) is saturated with a melamine formaldehyde (MF) resin in a one-step or a two-step impregnation process, wherein in the first step of the two-step process, the saturating resin comprises MF and UF resin in a MF:UF weight ratio of 0:100-100:0, and in the second step, the saturating resin comprises MF and UF resin in a MF:UF weight ratio of 98.5:1.5-100:0.
14 . A product comprising the thermally cured article according to claim 1 forming an outer surface thereof, wherein the product is for indoor use and is a cabinet, kitchen counter, laboratory bench, or indoor flooring, or the product is for outdoor use and is fencing, door, an outdoor kitchen surface, a façade element, roofing, a garden shed surface, a tool shed surface or outdoor flooring.
15 . The product according to claim 14 , wherein the product is for indoor use and is a cabinet, kitchen counter, laboratory bench, or indoor flooring,
16 . The product according to claim 14 , wherein the product is for outdoor use and is fencing, a door, an outdoor kitchen surface, a façade element, roofing, a garden shed surface, a tool shed surface or outdoor flooring.
17 . A process for forming the article ( 7 ) according to claim 1 , comprising:
printing on the untreated alpha-cellulose core layer ( 3 );
saturating the printed core layer ( 3 ) with a melamine formaldehyde (MF) resin; and
coating a coating layer ( 2 ) on a top surface of the saturated printed core layer ( 3 ).
18 . The process according to claim 17 , wherein the printed core layer ( 3 ) is saturated with a melamine formaldehyde (MF) resin in a one-step or a two-step impregnation process, wherein in the first step of the two-step process, the saturating resin comprises MF and UF resin in a MF:UF weight ratio of 0:100-100:0, and in the second step, the saturating resin comprises MF and UF resin in a MF:UF weight ratio of 98.5:1.5-100:0.
19 . A process for forming the article ( 7 ) according to claim 1 , comprising
laminating the coated overlay ( 1 ) to the panel substrate ( 4 ) optionally with the midlayer ( 5 ) between the overlay ( 1 ) and the substrate ( 4 ) and/or the backer sheet ( 6 ) on a bottom surface of the substrate ( 4 ), and thermally curing the article ( 7 ),
wherein the laminating is performed at a temperature of from 140 to 200° C. at a pressure from 1-4 MPa for 20 to 600 seconds.
20 . The process for forming the article ( 7 ) according to claim 18 , wherein the laminating of the coated overlay ( 1 ) to the panel substrate ( 4 ) optionally with the midlayer ( 5 ) between the overlay ( 1 ) and the substrate ( 4 ) and/or the backer sheet ( 6 ) on a bottom surface of the substrate ( 4 ), is performed with the coated overlay ( 1 ) having essentially no solvent prior to the laminating.
21 . The process for forming the article ( 7 ) according to claim 20 , wherein the coated overlay ( 1 ) has less than 0.1 wt. % of solvent prior to the laminating based on the total weight of the coated overlay ( 1 ).