CA2261403A1 - Diboride coated pressing surfaces for abrasion resistant laminate and making pressing surfaces - Google Patents

Abstract

A press plate for producing decorative laminate from resin impregnated paper, with alumina particles on its pressing surface, is coated with diborides selected from the group consisting of hafnium diboride, molybdenum diboride, tantalum diboride, titanium diboride, tungsten diboride, vanadium diboride, or zirconium diboride or mixtures thereof for making the press plate resistant to scratching. The preferred diborides are titanium and zirconium. The most preferred diboride is titanium. The color, gloss and surface appearance of laminate pressed with a titanium diboride coated press plate is substantially the same as laminate pressed with the press plate before coating.

Description

TITLE. O1BORIDE COATED PRESSING SURFACES FOR ABRASION
RESISTANT LAMINATE AND MAKING PRESSING SURFACES
INVENTOR: MUYUAN M MA AND JAY T. OLIVER
BACKGROUND OF THE INVENTION
1. Field of the invention This invention relates to coated) abrasion resistant press plates used in making abrasion resistant decorative laminate, to the coating of press plates and to the making of laminate with these press plates. Grit, e.g., alumina particles, on the pressing surface of abrasion resistant decorative laminate can scratch press plates and reduce the casual quality of laminate thereafter made with the press plate. Press plates of this invention are particularly useful in making abrasion resistant high gloss decorative laminate.

2. Description of the Related Art In the manufacture of decorative laminate, layers of resin impregnated paper are pressed against press plates under conditions of temperature and pressure to cure the resin and bond the layers together. A high gloss press plate imparts a high gloss surface to laminate. A textured surtace imparts a textured surface to laminate. These press plates are extremely uniform, with even microscopic discontinuities being minimized. The quality of a high gloss polished press plate can be determined by viewing reflected images on its surface and scrutinizing the reflected images for optical discrepancies. Grit on the surface of laminate causes micro scratching of stainless steel press plates normally used in the manufacture of decorative laminate, thus destroying the micro finish of the press plate. Press plates can also be scratched by press plate handling equipment and by debris from pressing equipment or materials used in making laminate. (Lawrence U.S. Patent 5,244,375) Melamine resin coated decorative laminate is pressed at temperatures of about 310°F (110-155°C) and pressures of about 300-2000 psi (20-136 bar) and preferably about 750-1500 psi (51-102'bar). Heating to these temperatures and cooling to room temperature results in substantial expansion and contraction of the laminate and of the press plate. Expansion and contraction of the laminate and press plate will not be the same, resulting in the movement of grit on the pressing surface of laminate across the press plate.
It is disclosed m National Electrical Manufacturers Association (NEMA) Standards Publication No. LD 3, that gloss finish laminate has a gloss of 70-100+. High gloss textured finish laminate is disclosed as having a gloss of 21-40. Black glass with a gloss of 9411 degrees. measured at an angle of 60 degrees, is disclosed as the NEMA
Standard 3.13.2) for calibrating a gloss meter for 60 degree angle gloss measurements.
Even discontinuities in high gloss press plates that can only be seen with a microscope can impart visible surface defects to a high gloss surface of laminate. Any scratching of high gloss press plates imparts visible surface defects to high gloss surfaces of laminate and reduce gloss level.
Grit on the decorafrve surface of laminate imparts abrasion resistance, a commercially desirable characteristic of laminate. Particles of alumina are commonly used as grit in making decorative laminate. The Vickers hardness of alumina is disclosed in 'Tribology: Friction and wear of Engineering Materials") I. M. Hutchings) CRC
Press, 24 1992, to be 1800 to 2000. A useful range of particle sizes is about 10 to about 75 microns. Grit of about 25-60 microns is preferred. Optimum abrasion resistance is obtained in the particle size range of about 40 to 60 microns. (Lane et. al.
U.S. Patent 3,798,111 ) Alumina having a maximum particle size of 9 microns is disclosed as being effective for imparting a wear resistant surface to glossy decorative laminate. Wear resistance is defined as ttie resistance of a glossy laminate to toss of gloss when the surface of laminate is exposed to the abrasive effects of sliding objects. It is acknowledged that the resulting laminate does not meet NEMA LD 3.01 requirements to be considered as ~0 abrasion resistant. However, it is disclosed that glossy press plates an:
not scratched substantially if the grit particle size is maintained at less than 9 micxons.
(Lex et. al.
U.S. Patent 4,971,855) The use of a 410 stainless steel press plate hardened by nitriding is disclosed for making high gloss decorative laminate. After pressing 100 sheets of high gloss laminate with 6 micron and 15 micron grit) the gloss of the pressed laminate remained good to very good. The rntnded press plate exposed to the 6 micron grit was rebuffed after 234 cycles and produced acceptable laminate quality for at least another cycles. Nitrided press plates exposed to 30 micron grit offered limited durability. It is disclosed that the 410 sta~niess steel press plate used for nitriding had a Rockwell) "C"
scale hardness of 38-45 and that the rntrided surface had a Rockwell, "C"
scale hardness of 60-70. The equwalent Vickers hardness of 410 stainless steel is about 370-440. based on a conversion table published in "Metals Handbook. Mechanical Testing") Vol. 8, 9th ed.. ASM. 1985. The equivalent Vickers hardness of nitrided 410 stainless steel is about 500-1000) based on a conversion table published in "Metals Handbook) Mechanical Testing", Vol. 8) 9th ed., ASM) 1985. (Lawrence U.S.
Patent 5,244,375) Laminate with 35 micron average particle size alumina at its surface (PGA 822 overlay, available commercially from Mead Corporation) has been pressed with high gloss press plates coated with titanium rntride. After ten pressings, the titanium nitride coated press plates had about 15 scratches per square centimeter. A control 410 stainless steel press plate had about 500 scratches per square centimeter. The Vickers hardness of titanium nitride is disclosed in 'Tribology: Friction and wear of Engineering Materials", I.
M. Hutchings, CRC Press. 1992, to be 1200 to 2000.
The control press plate and the press plate on which the titanium nitride was coated were cut from the same stainless steel pressing plate. The scratches was visible under a light microscope at 40X magrnfication. Titanium nitride was coated onto 410 stainless steel high gloss press plates m a magnetron sputter coating system. The use of a magnetron sputter coating system for applying a titanium nitride coating is disclosed in "Multi-Cathode Unbalanced Magnetron Sputtering Systems," Sprout. Surface and coating Technology, 49 (1991 ). The use of a magnetron sputter coating system for cleaning the surface that is to be coated is disclosed in "A New Sputter Cleaning System For Metallic Substrates," Schiller et. al., Thin Solid Films, 33 (1976).
Additionally, the color of the laminate pressed with the titanium nitride coated press plate was different than the color of the laminate pressed with the control press plate.
An ASTM D 2244 color difference in comparison to a standard of less than (t0.5) DE is considered as an acceptable. color match to the standard. The ASTM D 2244 color difference between a standard and laminate pressed with the titanium nitride coated press plate was greater than (0.5) DE. The titanium nitride coated press plate and laminate pressed therefrom had a bronze appearance. The control press plate and the laminate pressed therefrom did not have a bronze appearance. Laminate pressed with the control press plate had an ASTM D 2244 color difference when compared with the standard of less than (0.5)oE.
Iron-based cutting tools have been sputter coated w'tth 2-6 microns of titanium diboride.
The sputtering is carried out in an argon or krypton beam of ions accelerated to 1300-1800 volts as a broad-beam ion source. A titanium diboride target is arranged as a cathode. The tool is heated to about 200°C(392°~. Sputtering is done under a vacuum of about 4-6 milli-Torr. Titanium diboride has an extremely high Vickers micro-hardness value, typically about 3600, which is not only considerably higher than other borides but also substantially higher than other carbides or nitrides.
Titanium diboride is also particularly noted for its high density, e.g., 88% of theoretical density) a low resistivity of 30 micro-ohms centimeters) a high strength of about 40,000 psi, and a coefficient of thermal expansion which is about 8.1 x 10'" at the temperature range of 20°-800°C(68-1472°F). (Moskowitz et al., U.S. Patent Number 4,820,392) Control conditions for sputter coating are disdosed in "influence of Apparatus Geometry and Deposition Conditions on the Structure and Topography of Thick Sputtered ?0 Coatings" Thomton, Journal of Vacuum Science Technology, Volume 11, Number 4, (July/August 1974) and "Sputtering" Thomton et al.; Metals Handbook. Ninth Edition) American Society for Metals, Metals Park, Ohio) 44073) Volume 5, pp 412-416, (1982).
There is a need for a hard coating on a press plates, continuous belt, and other pressing surfaces that imparts a color to laminate having an ASTM D 2244 color difference in comparison to a standard of less than (~5) DE. There is a need for a coating that can be applied to a pressing surface without changing the appearance of the finish on the pressing surface. There is a need for a pressing surface that is not scratched when used in pressing laminate coated with alumina particles of greater than 10 microns and preferably greater than 25 microns. There is a particular need for a pressing surface that is not scratched when used in pressing high gloss laminate with an ASTM 2457 60 degree angle gloss of greater than 70, when the surface of the laminate is coated with 25-60 micron alumina particles.

SUMMARY OF THE~NVENTinN
It has now been discovered that the color, gloss and surface appearance of laminate made with pressing surfaces coated with diborides selected from the group consisting of hafnium dibonde, molybdenum diboride, tantalum diboride, titanwm diboride, tungsten diboride. vanadium diboride, or zirconium dibonde or mixtures thereof are substantially the same as the color and gloss of laminate made with the pressing surfaces before the coating is applied. The preferred diborides for coating laminate pressing surfaces are titanium diboride or zirconium diboride. The most preferred diboride for coating laminate pressing surtaces is titanium diboride. It is believed that titanium diboride is more commonly used commercially fot coating surfaces than other members of the diborides of this invention because it can be sputter coated in a magnetron sputtering system at a higher deposition rate.
The diboride coating of this invention can be applied on laminate pressing surfaces to have a Vickers hardness of at least 2000 and preferably at least 2200, suffiaent for pressing laminate with 25-60 micron or larger alumina particles at the pressing surface of the laminate without being scratched. A coating of about 3 microns has sufficient hardness to resist scratching by alumina particles on the: pressing surface of laminate.
The hardness of the coating can be controlled in a planar magnetron sputter coating system by those skilled in the use of these systems.
It has been discovered that the diboride coating of this invention can be coated on a pressing surface with sufficient bond strength for use in pressing high pressure laminate. A minimum bond strength of 1.6 and preferably 1.8 kilogram force (kgf) determined by diamond scratching bond testing is believed sufficient. Diboride coatings of greater than 6 microns can have lower bond strengths due to stresses produced during coating.
Bonding of the diboride coating of this invention to the pressing surface is enhanced by thoroughly cleaning the pressing surtace before introducing the pressing surface into a magnetron sputter coating system. Bonding is further enhanced by etching the pressing surtace with the magnetron sputter coating system prior to applying the titanwm diboride coating. Cleaning, anodic etching ( cathodic etching and etching with radio frequency (RF) can be' accomplished by methods known to those skilled in the use of a magnetron sputter coating system. It has been discovered that a layer of titarnum applied directly onto the pressing surface before applying the diboride coating of this invention further enhances the bonding of the dibonde. Improving bonding by cleaning, etching and the use of an intermediate layer between the coating and substrate are known to those skilled in the art of using magnetron sputter coating systems.
DETAILED DESCRIPTION OF THE INVENTION
Black. high gloss) high pressure laminate was pressed with titanium diboride coated press plates shown on Table 1. These press plates had been finished for imparting an ASTM D 2457 60 degree angle gloss of about 100 to laminate before being coated with titanium diboride. The ASTM O 2244 color difference between a standard and laminate pressed with the titanium dibonde coated press plates shown on Table 1 was less than (0.5) AE. Gloss and color differences on Table 1, are averages of measurements made on 10 laminates.
Table 1 Gloss and olor Diffpr~Pmr~s Press PIa~ ASTM Glo (a~ 60 A STM Color Diff er nc . D
3000-1 101 0.20 3000-2 100 0.25 0.35 6000-2 103 0.40 6000-3 102 0.30 6000-4 102 0.40 6000-5 103 0.45 6000-6 101 0.45 Additionally, high gloss Press Plate 3000-2 and a control press plate have been used in the pressing of 760 sheets of high pressure, black) high gloss laminate with 35 micron average particle size alumina particles on its pressing surface. Laminate was pressed with these press plates at about 1000 psi (68 bar) and 280°F
(138°C). The pressing surface of the laminate is commercially available overlay sheet with 35 micron alumina grit (PGA 822 from Mead). Press Plate 3000-2 and the control press plate were cut from a high gloss. 410 stainless steel press plate that had been finished for imparting an ASTM D 2457 60 degree angle gloss of about 100 to laminate. Press Plate s and the control press plate measure about twelve inches along one side and eleven inches along their other side. Press Plate 3000-2 was coated with about five microns of titanium diboride in a magnetron sputter coating system. The titanium diboride coating was applied in 17 scans, applying about 3000 angstroms of titanium diboride per scan.
The other was used as a control.
The first sheet of black. high gloss laminate with 35 micron average particle size alumina particles on its pressing surface pressed with the control press plate had an ASTM D 2244 color difference in comparison to a standard of about (0.25)AE.
The first sheet of black, high gloss laminate pressed with Press Plate 3000-2 had an ASTM D
2244 color difference in comparison to a standard of about (0.15) 0E.
The first sheet of black laminate pressed with the control press plate had an ASTM D
2457 60 degree angle gloss of about 100 to laminate. The 760th sheet of black laminate pressed with the control press plate had an ASTM D 2457, 60 degree angle gloss of less than 70. The control press plate imparted a 60 degree angle gloss of less than 90 to black laminate after it had pressed about 160 sheets. It is believed that laminate with a 60 degree angle gloss of less than 90 is not commercially acceptable as a high gloss laminate.
These 760 sheets of black laminate pressed with Press Plate 3000-2 had an ASTM
D
2457 60 degree angle gloss of about 100. Press Plate 3000-2 has been viewed under a microscope for scratches after pressing these 760 sheets of black laminate and none have been found. The control press plate is heavily scratched.
No differences were observed in the surface appearance of laminate pressed with the Press Plates shown on Table 1 and control press plates.
T'rtanwm diboride was coated onto the high gloss press plate in a magnetron sputter coating system under a number of conditions It is also believed that a coating of at least 3 microns is necessary for achieving a Vickers hardness of at least 2000 and that adhesion decreases at coating thicknesses of 6 microns or greater. . Hardness and adhesion can be controlled, as known to those skilled in the art, by the pressure and temperature under which press plates are coated with the diborides of this invention and the power (amperes and volts) used in coating the diborides of this invention on press plates.

A textured press plate coated with titanium dibonde, hereinafter "Press Plate 3000-3", and a control press plate been used in the pressing of greater than 450 sheets of high pressure. black. textured laminate with 35 micron average particle size alumina particles on its pressing surface. This laminate was pressed at about 1000 psi (68 bar) and 280°F (138°C). Press Plate 3000-3 and the control press plate were cut from a textured. 630 stainless steel press plate that had been finished for imparting an ASTM
0 2457 60 degree angle gloss of about 10 to laminate. Press Plate 3000-3 and the control press plate measure about twelve inches along each side. Press Plate 3000:3 was coated with about six microns of titanium diboride in a magnetron sputter coating system. The titanium diboride coating was applied in 20 scans, applying about angstroms of titanium dibonde per scan.
The first sheet of this black, textured laminate pressed with the control press plate had an ASTM D 2244 color difference in comparison to a standard of about (0.22) eE.
Black) high gloss laminate pressed with Press Plate 3000-3 had an ASTM D 2244 color difference in comparison to a standard of about (0.08) oE.
The first sheet of this black laminate pressed with the control press plate had an ASTM
D 2457) 60 degree angle gloss of about 9.5. The 450th sheet of this black laminate pressed with the control press plate had an ASTM D 2457) 60 degree angle gloss of about 8. This black laminate pressed with Press Plate 3000-3 had an ASTM D
2457, 60 degree angle gloss of about 10.
No differences were observed in the surface appearance of laminate pressed with the Press Plate 3000-3 and a control press plate.
The press plates on Table 1 and Press Plate 3000-3 were cleaned and then etched under radio frequency conditions in a planar magnetron sputter coating system.
These press plates were then coated with titanium diboride in the magnetron sputter coating system under the following averaged conditions.
Cleaning ~ chemical cleaning wipe with ethanol, trichloroethane and acetone ~ physical cleaning 5 minute nitrogen gas blow over press plate Radio Freau _nrh. ~trhing Conditions gas medium argon in./ minute (cm.J minute) scan speedi(2.54}

mTorr 10 mA/sq. in. (mA/sq. cm.) 3.5(.54) kV .75 Titanwm Diboride oatina ('re diti n ons argon gas medium in./ minute (cm./ minute) scan speed1(2.54) mTorr 7 mA/sq. in. (mA/sq. cm.) 83(13) kV .3 Coating Condition and ProoPrti~Pt Press Plate Scan RateScans ThicknessAdhesionHardness /scan microns kgf kgf 3000-1 3000 14 4.2 1.T 2280 3000-2 3000 17 5.1 2.1 2830 3000-3 3000 20 5.5 2.0 2700 6000-1 6000 6 3.7 1.8 1940 6000-2 6000 6 3.7 1.8 2160 6000-3 6000 7 4.4 1.8 2250 6000-4 6000 7 4.3 2.0 2190 6000-5 6000 10 6 2.2 2880 6000-6 6000 10 6 2.0 2850 micron =
10.000 A
units Three high gloss press plates, measuring about four feet by eight feet, of this invention have been made. These press plates are referred to as Press Plates 3-1, 3-2) and 3-3.
These press plates were sputter coated with titanium diboride under planar magnetron discharge conditions.
Press Plates 3-1, 3-1, and 3 ~3 were anodically etched and then coated with titanium and titanium diboride in a planar magnetron sputter coating system under the following averaged conditions. These press plates were chemically cleaned before they were s placed into the sputter coating system. The temperature of these press plates during etching_ and coating was about These press 300F(149C). plates did not warp at this temperature Cleanma Press Plat ~ -1 '~ 2 and 3 p chemical cleaning wipe with ethanol) trichioroethane and acetone Anodic Etching Conditions lprecc 3 1 3 3 31 Plafag gas medium argon argon argon in.l minute (cm.l minute) scan 3(7.6) 3(7.6)3(7.6) speed mTorr 25 24 10 mAlsq. in. (mA/sq. cm.) 4.6(.72) 2.9(.45)2.9(.45) kV .24 .23 .24 number of scans 1 1 5 ~t ium Coating Conditions lPrPCC 3 1 ~ ~ 3 ~
plates gas medium argon argon argon in.l minute (cm.l minute) scan 3(7.6) 3(7.6)3(7.6) speed mTorr i .6 1.2 2.7 mAlsq. in. (mAlsq. cm.) 70(11) 70(11)70(11) kV .52 .52 .43 - number of Ti scans 1 1 1 Titanium piboride Coating iC'~~r~itionstes 3 1 ~~
(Press Pla 3~3~
gas medium argon argon argon in./ minute (cm./ minute) scan 3(7.6) 3(7.6)3(7.6) speed mTorr 1.6 1.2 2.7 mA/sq. in. (mA/sq. cm.) 71(11) 75(12)70(11) kV .52 .60 .50 number of TiBz scans 8 12 18 deposition rate (A/scan) 4125 5500 3000 Properties of T'id2~ Coating (Pr cc pl a~c ~ 1 ~ 9 3 3) thickness (microns) 3.3 6.6 5.4 adhesion (kgf) . 1.2' hardness (kgf) 2000 2500 *' * TiBz~ coating separated from during Press Plates 3-1 and 3-2 the pressing of laminate.

"' The hardness and adhesiq~n of Press Plate 3-3 has not been measured. Hardness and adhesion testing destroys the surface of a press plate.

Press Plate 3-3 has been used in the pressing of greater than 1200 sheets of high pressure. black, high gloss laminate with 35 micron average particle size alumina particles on their pressing surfaces. Press Plates 3-3 was viewed for scratches after pressing these 1200 sheets of laminate and none have been found. The titanium dibonde coating on Press Plates 3-1 and 3-2) separated from the stainless steel substrate after pressing less than 100 sheets of laminate.
A zirconium diboride coated high gloss press plate of this invention and a control press plate have each been used in the pressing of 10 sheets of black) high gloss laminate.
This laminate had an ASTM 0 2244. color difference in comparison to a standard of about (0.26) of and an ASTM D 2457) 60 degree angle gloss of about 100. No differences were observed in the surface appearance of laminate pressed with the zirconium coated and control press plates.
A zirconium diboride coated high gloss press plate of this invention has been used in i 5 the pressing of 10 sheets of btadc, high gloss laminate with 35 micron average partite size alumina particles on its pressing surface. This laminate was pressed at about 1000 psi (68 bar) and 280°F (138°C). A commercially available overlay sheet with 35 micron alumina grit {PGA 822 from Mead) is the pressing surface of the laminate. No scratches were observed on this press plate after the pressing of these 10 sheets of laminate.
This zirconium diboride press plate was cut from a high gloss) 410 stainless steel press plate having an ASTM D 2457) that had been finished for imparting a 60 degree angle gloss of about 100 to laminate. Two press plates measuring about twelve inches along each side were cut from this press plate. One was coated with about five microns of zirconium diboride in a planar magnetron sputter coating system. This press plate was etched under radio frequency conditions for about 15 minutes before the titanium diboride coating was applied. A 6 micron zirconium diboride coating was applied in 15 scans, applying about 4,000 angstroms of zirconium diboride per scan in a planar magnetron sputter coating system under the following averaged condi5ons.
Clef ~ chemical cleaning wipe with ethanol, trichloroethane and acetone ~ physical cleaning 5 minute nitrogen gas blow over press plate m Radio Freauencyr t hin9 Conditions gas medium argon in./ minute (cm./ minute) scan speed1 (2.54}

mTorr 10 mA/sq. in. (mA/sq. cm. ) 3.5(.54) kV .75 Zirconium Diborid C
ti C
it e oa argon ng on- d ~
gas medium in.l minute (cm.l minute) scan speed1(2.54) mTorr 7 mAlsq. in. (mA/sq. cm.) 56(9) kV .4 Black) laminate has been pressed with press plates, measuring six inches by six inches (15.24 cm X 15.24 cm), coated with titanium nitride in a magnetron sputter coating system. The test results shown on Table 3 are the average results of pressing five sheets of laminate with each press plate.
Table 4 Laminate Pressed With Titani ~m Nitride Coated Press plates control #8#8 TiN #8 control..l~2 ASTM Gloss @ 60° 100 95 100 95 ASTM Color Difference, AE 0.30 0.75 0.35 0.90 The gloss of the laminate pressed with the titanium nitride coated press plate was tower than the gloss of laminate pressed with the control press plate. The color of the laminate pressed with the titanium nitride coated press plate was significantly different from the color of the laminate pressed with the uncoated control press plate.
The titanium nitride coated press plates and laminate pressed with the titanium nitride press plates had a bronze appearance. .
Black, laminate has been pressed with press plates) measuring six inches by six inches (15.24 cm X 15.24 cm)) coated with niobium nitride in a magnetron sputter coating system. The test results shown on Table 4 are the average results of pressing five sheets of laminate with each press plate.

Claims (24)

1. A planar pressing surface for producing decorative laminate from resin impregnated paper, said pressing surface comprising:
a planar surface coated with diborides selected from the group consisting of hafnium diboride, molybdenum diboride, tantalum diboride, titanium diboride, tungsten diboride, vanadium diboride, or zirconium diboride or mixtures thereof in a planar magnetron sputter coating system to a Vickers hardness of at least 2000.

2. A planar pressing surface of claim 1, wherein the surface is coated with diborides in a planar magnetron sputter coating system to a Vickers hardness of at least 2200.

3. A planar pressing surface of claim 1, wherein the surface is coated with diborides selected from the group consisting of titanium diboride or ziconium diboride or mixtures thereof.

4. A planar pressing surface of claim 1, wherein the surface is coated with titanium diboride.

5. A planar pressing surface of claim 1, wherein the surface is first coated with titanium in a planar magnetron sputter coating system and then with diborides.

6. A pressing surface of claim 1, wherein the diboride coating has a thickness of at least 3 microns.

7. A planar pressing surface of claim 1, wherein the diboride coasting has a thickness of not more than 8 microns.

8. A press plate having planar pressing surfaces for producing decorative laminate from resin impregnated paper, said press plate comprising:
planar surfaces coated with titanium diboride in a planar magnetron sputter coating system to a Vckers hardness of at least 2000.

9. A pressing surface of claim 8, wherein the planar surfaces are coated with titanium diboride in a planar magnetron sputter coating system to a Vickers hardness of at feast 2200.

10. A press plate of claim 8, wherein the planar surfaces are first coated with titanium in a planar magnetron sputter coating system and then with titanium diboride.

11. A press plate of claim 8, wherein the titanium diboride coating has a thickness of at least 3 microns.

12. A press plate of claim 8, wherein the titanium diboride coating has a thickness of not more than 6 microns.

13 13. A method of making a planar pressing surface for producing decorative laminate from resin impregnated paper, comprising;
imparting a desired finish on a planar pressing surface;
removing contaminants from the planar surface; and coating the planar surface with diborides selected from the group consisting of hafnium diboride, molybdenum diboride, tantalum diboride, titanium diboride, tungsten diboride, vanadium diboride, or zirconium diboride, or mixtures thereof in a planar magnetron sputter coating system to a Vickers hardness of at least 2000.

14. A method of making a planar pressing surface of claim 13, wherein the surface is coated with diborides in a planar magnetron sputter coating system to a Vickers hardness of at least 2200.

15. A method of making a planar pressing surface of claim 13, wherein the surface is coated with diborides selected from the group consisting of titanium diboride or zirconium diboride or mixtures thereof.

16. A method of making a planar pressing surface of claim 13, wherein the surface is coated with titanium diboride.

17. A method of making a planar pressing surface of claim 13, wherein the surface is first coated with titanium in a magnetron sputter coating system and then with diborides.

18. A method of making a planar pressing surface of claim 13, wherein the diboride coating has a thickness of at least 3 microns.

19. A method of making a planar pressing surface of claim 13, wherein the diboride coating has a thickness of not greater than 6 microns.

20. A method of making a press plate having planar pressing surfaces for producing decorative laminate from resin impregnated paper, comprising:
imparting a desired finish on the planar pressing surfaces;
removing contaminants from the pressing surfaces; and coating the planar surfaces with titanium diboride to a Vickers hardness of at least 2000.

21. A method of making a press plate of claim 20, wherein the planar surfaces are coated with titanium diboride in a planar magnetron sputter coating system to a Vickers hardness of at least 2200.

22. A method of making a press plate of claim 20, wherein the planar surfaces are first coated with titanium in a magnetron sputter coating system and then with titanium diboride.

23. A method of making a press plate of claim 20, wherein the titanium diboride coating has a thickness of at least 3 microns.

24. A method of making a press plate of claim 20, wherein the titanium diboride coating has a thickness of not greater than 6 microns.