JPS6335419B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to laminates, particularly decorative laminates with high abrasion resistance. High-pressure decorative boards are conventionally manufactured by stacking multiple layers of paper impregnated with various synthetic thermosetting resins and curing them under high temperature and high pressure. In reality, such a pile consists of a plurality of sheets from the bottom, for example, 3 to 8 sheets.
Consists of a core sheet made of phenolic resin-impregnated kraft paper, a pattern sheet or decorative sheet on top of the core sheet impregnated with melamine resin, and an overlay sheet on top of the decorative sheet.In the laminate, the overlay sheet is almost transparent and protects the pattern sheet. are doing. Traditionally, core sheets have a series weight of approximately 41-57Kg (90
~125 lbs.) kraft paper. The weight of a series is the weight of 500 sheets of paper measuring 61 x 91 cm ² ( ²⁴ x 36 inches ² ), so the weight of a series is the weight of 3000 feet ² of paper. Before stacking, the kraft paper is impregnated with a water-alcoholic solution of phenol-formaldehyde resol resin, dried and partially cured in a hot air oven, and finally cut into sheets. The decorative sheets are of high quality and range in series weight from 23 to 57Kg (50 to 125 lbs)
α-cellulose paper filled with a pigment, impregnated with a water-alcoholic solution of melamine-formaldehyde resin, dried and partially cured, and finally cut into sheets. Decorative sheets are usually printed with decorative patterns or gravure reproductions of natural materials such as wood, marble, leather, etc. before being impregnated with resin. Overlay sheets are used whenever printing the surface of a decorative or patterned sheet to protect the print from abrasion. The overlay sheets are a series of high quality α weighing approximately 9-14Kg (20-30 lbs)
- Cellulose paper impregnated with melamine-formaldehyde resin in the same manner as for decorative sheets, except that the amount of resin per unit weight of paper is greater. When the individual sheets are stacked as described above, the final laminate thickness is approximately 1.3 mm (50 mils) when using 6 impregnated core sheets.
becomes. It goes without saying that laminates of different thicknesses can be obtained by using different numbers of sheets. A stack of sheets as described above is placed between polished steel plates and heated to approximately 110-171℃ (230-340〓) (for example, 149
℃ (300〓)) temperature and 56~112Kg/ ^cm2 (800~
A pressure of 1600 psi) (eg, 70 Kg/cm ² (1000 psi)) is applied for a sufficient time (eg, 25 minutes) to consolidate the laminates and cure the resin. This causes the resin within the sheets to flow and harden, and the sheets unite into a single laminate known to those skilled in the art as a high pressure decorative laminate. In practice, the two laminate stacks are separated by a release sheet and pressed back to back so that the two laminates are peeled off after separation. To obtain a laminate with a low gloss and slightly textured surface, the bulk of the deposit is placed between the overlay sheet and the metal plate with the aluminum foil-kraft paper composite with the aluminum side facing the overlay sheet. Insert and stack the sheets. After the lamination process is complete, the back of the laminate is papered and bonded to particle board, plywood, or other support. The bonded laminate-faced panels are then fabricated into furniture, kitchen counter decks, table decks, point-of-sale fixtures, and other end uses that are widely accepted for their combination of appearance, durability, and economy. . Many variations of the general process described above are known, particularly those designed to achieve special effects in appearance and texture. Other curing cycles are also possible, and indeed other resin systems are sometimes used as well. In addition to the high pressure decorative laminates described above, there are also a number of low pressure products that have been developed in recent years, including low pressure laminates using saturated polyester resins or melamine-formaldehyde resins. One of the fastest growing materials comparable to high-pressure laminate in recent years is a product called low-pressure melamine plank, which typically produces 12-16 kg/cm ² (175-225 psi) at 163-177°C (325-350〓). Pressed for a short time under pressure. These low-pressure products usually have the advantage of being inexpensive, but cannot be labeled as "high-pressure laminates." This is because the qualifications for high-pressure laminates include standards for wear, strain resistance, heat resistance, impact resistance, dimensional stability, etc.
Association (National Electric
Manufacturers Association）NEMA LD3−
This is because products must pass various stiffness standards promulgated in 1975. Although various other printed and surfaced materials, such as low pressure laminates, have desirable property criteria, no product other than high pressure decorative laminates currently on the market possesses all of these properties. One of the most important of these properties is abrasion resistance. High pressure veneers must have sufficient abrasion resistance to withstand use in highly exposed areas such as dining room furniture face decks, checkout counters, etc. The standard NEMA test for abrasion resistance is NEMA test LD-3.01. In this test, a sample of the laminate is pressed against a graduated sandpaper strip onto a rotating disk, and two weighted rubber wheels are placed above the rotating disk. As the surface of the laminate rotates under the wheels, the abrasive action of the sandpaper gradually cuts away at the overlay until the surface of the laminate is cut away and the printed pattern is exposed and destroyed. The NEMA standard for class 1 laminates is that pattern destruction of the laminate after 400 revolutions does not exceed 50%. The 50% end point is estimated by the average of the number of rotations when the pattern first shows wear and the number of rotations when the pattern is completely destroyed. When manufacturing high-pressure decorative laminates using conventional methods,
The resin content in the decorative or patterned sheet is usually 35-40% and the abrasion resistance is only about 50-75 times without the overlay sheet. If a specially formulated melamine resin is used in the pattern sheet, with a resin content of 50-55%, abrasion resistance of no more than about 150-200 cycles can sometimes be obtained without an overlay sheet, but in this latter case the laminate is It is quite difficult to prepare as it tends to cause surface cracking and is difficult to evenly impregnate the decorative sheet. Additionally, the latter laminates do not pass the minimum 400 cycles required by NEMA standards. Nevertheless, it is desirable to produce laminates without overlay sheets that can reach the performance characteristics of laminates using overlays, especially laminates that exhibit 400 wear resistance. Furthermore, it is possible to produce laminates that have an abrasion resistance of 400 cycles and have a first wear point at least equal to the first wear point of high pressure decorative laminates with conventional overlays, typically 175 to 200 cycles. desirable. This is because, in practical use, the appearance of the laminate becomes unsatisfactory not when 50% of the pattern is destroyed, but when a lower percentage of pattern destruction occurs. It is known from years of field experimentation that conventional laminates with overlays having a first wear point of 175 to 200 wears have a satisfactory appearance when used in severe applications, at least with normal replacement cycles, and commercial It can be appreciated that many laminates for commercial use are replaced for fashion reasons rather than pattern wear. Therefore, laminates without overlays should pass the same criteria. In other words, such a laminate is at least
It should have both a NEMA abrasion resistance of 400 times and a first wear point in the same test of at least 175-200 times. Even if the latter requirement is not part of the NEMA standard. It would be desirable to be able to exhibit these properties without using an overlay for the following reasons. 1 The use of overlays substantially increases raw material costs in the manufacture of laminates. That is, the cost of the overlay paper itself, the cost of the resin used to impregnate the overlay paper, and the in-process and handling losses of these raw materials are increased. 2. Overlays impair the brightness of the desired pattern by placing a significant intermediate layer between the decorative sheet and the viewer's eye. The refractive index of the cellulose fibers used to form the overlay paper is close to that of the cured melamine-formaldehyde resin. The fibers are therefore hardly visible within the cured laminate and the printed pattern is visible with little fading. However, modern printing technology is able to reproduce natural products very accurately, especially various wood veneers. Since the printed reproduction approaches natural veneer in appearance, even a small amount of haze caused by the overlay paper is visually dull and seriously impairs the realism desired by the user. 3 Additionally, overlays contribute to the reject rate of manufactured laminates. Impregnated and dried overlay sheets tend to attract small dust particles because they develop a static charge during drying. This dust is difficult to detect and remove before lamination, resulting in a dirty laminated sheet that cannot be recycled. Additionally, the impregnated and dried overlay is brittle and difficult to handle without breaking. Debris becomes trapped on the surface of the overlay, resulting in a visually defective sheet. Furthermore, laminates containing overlays, especially those with relatively high surface gloss, will dull very quickly even after being subjected to even slight abrasion. This is inconvenient when a glossy laminate is desired. Improving wear resistance is a long-standing problem in the field. Many solutions have been proposed for this problem,
There were some that actually developed industrially. Nevertheless, NEMA wear resistance of at least 400 times without the use of overlay sheets and at least
It has not been previously possible to provide a laminate with a first wear point of 175 to 200 identical tests. It is known that small, hard mineral particles in the overlay sheet or in the resin mixture coating the impregnated pattern sheet can improve the wear resistance of high pressure laminates (e.g., Michl, US Pat. No. 3,135,643). (see U.S. Pat. Nos. 3,373,071 and 3,373,070 to Fuerst).
These techniques do not eliminate the overlay, but provide improved wear resistance or alternation of the overlay and associated resin. For example, US patent no.
In No. 3,123,515, an overlay sheet is impregnated with fine frit powder. This overlay is used by placing it on top of a decorative or patterned sheet in the usual manner. Another technique, disclosed in US Pat. No. 3,798,111 to Lane et al., impregnates small mineral particles, preferably alumina, into and near the top layer of the base paper during manufacture. Experiments have shown that laminates made with Rain et al.'s decorative sheet without an overlay have initial wear values of less than 100 cycles, and some as high as 35 cycles. Furthermore, in the abrasion discoloration test to determine initial wear, such laminates exhibit only a slight
After 3,000 rubs, the pattern began to break down. Other prior art of interest related to the background of the present invention includes U.S. Pat. No. 3,445,327 to Ferst;
U.S. Patent No. 3928706 by Gibbons
No. 1 and Merriam U.S. Patent No.
There is No. 3661673. Other techniques of somewhat less interest include U.S. Pat. Nos. 3,259,537 and 3,157,518 to Battista and U.S. Pat. and U.S. Patent No. 3318760 by Boenig.
There is a number. Although there has been considerable activity in the field to solve the above-mentioned problems, to date these problems have not been resolved. It is an object of the present invention to pass the qualification of NEMA abrasion standards while not including an overlay sheet, and further to have an initial wear point of at least 175 in the same test.
It is to provide high pressure decorative board which is ~200 times. These and other objects of the present invention provide for the preparation of conventional printed or otherwise decorated patterned paper.
Covered with an ultra-thin layer containing small mineral particles fixed in place on the paper by a suitable binder, such decorative sheet is then conventionally impregnated with a suitable thermosetting resin, such as a melamine resin, to form an overlay sheet. This was achieved by using a decorative sheet that does not use decorative sheets. These and other objects in the nature and advantages of the present invention will become more apparent from the detailed description of the embodiments taken in conjunction with the accompanying drawings. A new composition containing small mineral particles has been discovered. When such compositions are coated on unimpregnated patterned paper without the use of resin, surprising properties are obtained due to the use of patterned paper in the manufacture of decorative laminates without the use of overlay sheets, and the abrasion resistance of the resulting laminates is improved. The quality is excellent. In a preferred embodiment, the coating composition is a mixture of small particles of alumina and smaller amounts of microcrystalline cellulose particles dispersed in a stable aqueous slurry. Alumina particles, small enough in size not to interfere with the visual effect in the final product, serve as the wear-resistant material, and microcrystalline cellulose particles serve as the preferred binder. The binder must be compatible with the resin system used in the lamination step, usually a melamine resin or, in the case of low pressure laminates, a polyester resin system. In addition to this function, microcrystalline cellulose also serves to stabilize small particles of alumina on the surface of the decorative sheet. Referring to Figure 1, a preferred operation involves dispersing conventional unimpregnated printed or patterned paper into a stable aqueous slurry of a mixture of hard mineral particles and a binder, preferably alumina and microcrystalline cellulose particles. (), and the coating is dried at high temperature, for example in a hot air oven (), with a thickness of only 0.5-8μ (0.02-
The coating should be 0.3 mil (0.3 mil) thick. The resulting anti-abrasion coated paper (FIG. 2) is then impregnated with melamine or polyester resin () and dried in a conventional manner. At this stage, the lamination process () is ready. According to FIG. 3, the wear-resistant resin-impregnated decorative sheet 6 with an ultra-thin coat of anti-wear agent on the upper surface of the decorative sheet is stacked for the lamination step in a conventional manner except that no overlay sheet is used. ing. The laminate is then cured under heat and pressure in a conventional manner. The properties of the ultra-thin coating 4 are that it provides wear resistance to the final laminate even if it is very thin;
Not only does it meet NEMA standards of 400 times, but also 175-200
Give the first wear point more than once. It is also surprising that when the printed paper is impregnated with melamine resin, the coating adheres firmly to the surface of the paper without any mineral particles remaining in the impregnating solution or migrating from the surface of the paper. A further feature of this coating is that it does not interfere with the penetration of the melamine-formaldehyde resin solution into the interior of the paper during the impregnation step. Such penetration is absolutely necessary.
That is, the patterned sheet may be irregularly deficient in resin, for example in its center, and may delaminate after pressing. A further desirable feature of this coating is that it does not scatter or attenuate light;
The result is a very clear and consistent pattern in the final laminate. Without being bound by the following theory, the improved features of the present invention can be explained as follows. That is, microcrystalline cellulose particles contain very large external forces that bind different polar substances such as cellulose and alumina. Thus, the aqueous slurry of microcrystalline cellulose and alumina is stable and does not readily settle, despite the instability of the alumina particles in the water. Furthermore, when this slurry is coated on paper, the microcrystalline cellulose apparently binds the alumina particles to the surface fibers of the paper and the surface of the ink pattern, preventing the alumina particles from migrating below the surface. This can explain that good wear resistance can be obtained with a small amount of alumina. All or substantially all of the alumina particles thus remain on the surface, which is more effective than being dispersed below the surface. This is because when dispersed below the surface, it contributes little to the initial wear resistance. As mentioned above, a preferred slurry composition is a mixture of small particles of alumina and smaller amounts of microcrystalline cellulose particles dispersed in water. The small mineral particles must be present in sufficient quantities to provide the product with the desired abrasion resistance properties as described above, and the binder must be present to hold the mineral particles in place on the surface of the decorative sheet. Must be present in sufficient quantity. Generally, satisfactory results have been obtained using about 5 to 10 parts by weight of microcrystalline cellulose to about 20 to 120 parts by weight of alumina. Although it is possible to do it outside this range, it provides no advantage and complicates handling issues. The amount of water in the slurry should also be considered empirically. This is because too little water will make the slurry thick and difficult to use. Similarly, too much water will dilute the slurry and make it difficult to maintain a constant thickness as the slurry flows during the coating process. Thus, a slurry containing about 2.0% microcrystalline cellulose and about 24% alumina by weight of water is stable. That is, alumina does not settle. However, if more than about 3.5% by weight of microcrystalline cellulose and about 24% by weight of alumina are used based on water, the slurry becomes thixotropic and difficult to use. Preferably, the composition also includes small amounts of a wetting agent, preferably a non-ionic wetting agent, and a silane. The amount of infiltrant is not critical, but a very small amount is desirable;
Excessive amounts are disadvantageous. When silane is used, it acts as a coupling agent that chemically bonds the alumina particles to the melamine matrix after impregnation and curing, so that the alumina particles are not only mechanically bonded to the melamine resin, but also chemically bonded. Even if it wears out, it remains in the appropriate place, so the initial wear resistance is good. The silane is selected from a group that is compatible with the particular thermoset laminating resin used. In this regard, silanes containing amino groups, such as gamma-aminopropyltrimethoxysilane, are particularly effective for use with melamine resins.
The amount of silane used does not need to be very large; in fact, as little as 0.5% based on the weight of the alumina is effective in improving the wear resistance of the final laminate. It is believed that about 2% by weight, based on the weight of the alumina, is the maximum. This is because more than that will make little difference to the result and will simply increase the cost of raw materials. It is an important feature of the invention that coatings using microcrystalline cellulose as a binder must be dried at high temperatures before the decorative sheet is impregnated with melamine resin. Thus, the minimum drying temperature is approximately 82°C.
(180〓), and the preferred drying temperature is 116-132℃
(240~270〓). Alumina is preferred as the wear-resistant mineral particles. Silica, which has been suggested in prior art patents as a wear-resistant material, shows considerably poorer results in the present invention than alumina. Other sufficiently hard minerals such as zirconium oxide, cesium oxide, diamond powder, etc., may also be used, but they are expensive in practice and may cause color shift in some environments.
Glass beads are not suitable. Silicone carbide was also tried, but although it showed good abrasion resistance, the color shift was severe. The size of the alumina particles is an important characteristic. 20μ
Particle sizes below provide insufficient abrasion resistance, and the preferred minimum particle size is about 25μ. The maximum particle size is limited by the surface roughness of the product and whether it interferes with the visual effect. The preferred maximum dimension of the alumina particles is about 50 microns. The binder nature of the mineral particles is a very important feature in the present invention. Of all the materials tried,
Microcrystalline cellulose is by far the most satisfactory material.
In addition to holding the mineral particles in place on the surface of the decorative sheet, the binder must also act as a suspending agent in the slurry (otherwise additional suspending agent must be added). The unique feature of microcrystalline cellulose is that it acts as a typical suspending agent and film-forming agent, but unlike other reagents, it is highly porous and can be penetrated by thermosetting resins without dissolving in water before or after suspension. It is to form a film. In addition, the binder must be compatible with the laminating resin, and microcrystalline cellulose is compatible with both melamine and polyester resins.
Furthermore, the binder must not scatter or attenuate light even at its concentration in the final laminate, and microcrystalline cellulose is equally satisfactory in this regard. Other binders that may be used, but with inferior results compared to microcrystalline cellulose, include:
There are a variety of typical suspending-binding agents, including anionic acrylic polymers, carboxymethyl cellulose, and similar materials such as hydroxypropyl cellulose, methyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, and the like. However, as mentioned above, microcrystalline cellulose is by far the preferred binder. Microcrystalline cellulose is a non-fibrous cellulose in which the cell walls of cellulose fibers are cut into pieces with a length of several microns to several + microns. It is purified α-cellulose rather than a chemical derivative. Microcrystalline cellulose is commercially available under the trade name ``AVICEL,'' and its manufacturing process is described in U.S. Patent No. 1 by Batista.
Disclosed in No. 3275580. AVICEL type RC581
is a white, odorless, hygroscopic powder. It is water-dispersible and contains about 11% sodium carboxymethyl cellulose as a protective colloid. Its particle size is less than 0.1% on a 60 mesh screen. Features and advantages of the invention that are considered to be of particular importance are as follows. (1) A mixture of alumina particles and microcrystalline cellulose is deposited from an aqueous slurry rather than used as a filler in a resin solution. (2) Coating such a slurry onto an unimpregnated printed pattern sheet rather than an impregnated pattern sheet. (3) Dry the coating at a high temperature of at least about 82°C (180°C). (4) The coating thickness is 0.5-5μ (0.02-0.2 mil) instead of 25-51μ (1-2 mil). (5) After coating and drying, the patterned sheet is impregnated with a thermosetting resin using conventional equipment rather than coating with a thick slurry that is difficult to control. (6) This ultra-thin layer exhibits good wear resistance. Desirable attributes of alumina particle binders, all of which apply to microcrystalline cellulose, are that the binder acts as a film former, acts as a binder for mineral particles, and acts as a suspending agent for mineral particles in slurries. The thermoset impregnation resin must be permeable (in fact Microcrystalline cellulose forms a porous film), is resistant to the heat generated during the lamination process, and does not scatter or attenuate light in the laminate. An example is shown below for explanation. Example 1 Microcrystalline cellulose (AVICEL RC 581) was added to water being stirred in a hot blender. 2
After ~3 minutes the AVICEL was completely dispersed in the blender. Add alumina (Microgrit WCA) and stir gently. Finally, three drops of TRITON X-100 (nonionic detergent) were added to promote infiltration. The resulting slurry was applied as a coating to 29 kg (65 lbs.)/ream of unimpregnated patterned sheet with a wood grain finish. The coating was dried at 130°C (265°C) for 3 minutes. The paper was then saturated using melamine-formaldehyde resin in conventional manner and dried by conventional procedures. The resin content is 45-48%,
The volatile content was 5-6%. Make a laminate,
Traditional general purpose work cycle, i.e. approx. 149
Approximately 25 at ℃ (300〓), 70Kg/cm ² (1000psi)
Pressed for a minute. Formulation and abrasion resistance results are shown below for a 38μ (1.5 mil) wet coating. The dry film thickness was calculated to be 4μ (0.15 mil).

[Table] In the above table, MICROGRIT WCA is a micro-computer in Westfield, Massachusetts.
Abrasives Corporation (Micro
Alumina wrap powder manufactured by Abrasives Corporation. From the above comparative experiments, it can be seen that satisfactory results cannot be obtained with microcrystalline cellulose alone (Experiment 2), and good results cannot be obtained even when alumina with a particle size of 20 μm or less is used (Experiment 6). When MICROGRIT alumina with an average particle size of 20μ or more was used, both the initial wear resistance and the NEMA wear resistance were satisfactory. Furthermore, the resulting laminates have sharper patterns compared to conventional laminates with overlay sheets, and such laminates also
It also passed the durability test. Example 2 Four slurries were prepared similarly to Experiment 3 in Example 1. Each was coated to 76μ (3 mil) on 29 Kg (65 lb) of unimpregnated paper and dried as in Example 1 to a dry coating thickness of about 8μ (0.3 mil). The dried papers were impregnated with melamine resin and stacked as shown in FIG. Lamination was performed as described in Example 1. The only variable in the four experiments was the average particle size of the alumina. The results are as follows.

[Table] Example 3 Example 2 using alumina particles with an average particle size of 40μ
We conducted three experiments in the same manner. The only variable in this experiment was the wet film thickness. The laminates were compared as in Example 2. Show the results. Table 3 Pattern breakage at 500 cycles of wet coating thickness 3 mils (dry coating 0.3 mils) 1% 2 mils (〃 0.2 mils) 10% 1 mils (〃 0.1 mils) 30% Example 4 Slurry to coat decorative sheets The procedure of Example 1 was repeated using the following composition. 250ml 7.5g water 60g microcrystalline cellulose 1 drop alumina with average particle size 40μ TRITON As for the wear resistance after lamination, the first pattern failure did not occur even after 500 times. Example 5 The procedure of Example 4 was repeated using the same coating composition except that 120 grams of alumina with an average particle size of 30 microns was used. Wet film thickness 13μ (1/2 mil), 25μ
(1 mil) and 38μ (1.5 mil). The wear resistance of the final laminate after 500 cycles was as follows. Table 4 1/2 mil (0.05 mil dry coating) 10% pattern failure 1 mil (0.1 mil dry coating) <1% 1.5 mil (0.15 mil dry coating) <1% The three laminates also I was satisfied. Machinability was good with no chipping. After impregnation and pressing, the physical properties examined for the third sample (prepared from paper with a 3μ (0.1 mil) coating) according to NEMA standard LD3-1975 were as follows: Table 5 Abrasion resistance ＞500 times contamination resistance No effect Moisture absorption 6.5% Swelling degree of core board 8.9% Impact resistance (no support) 36〃 Radiant heat (no support) Hot water for 185 seconds No effect Hot wax No effect Dimensional stability: 0.24% in longitudinal direction, 0.56% in transverse direction. All results were satisfactory or excellent. Example 6 In the experiment of Example 4, instead of alumina, 60g
Experiments using MICROGRIT SIC 400 (27μ silicone carbide) and 60μ instead of alumina
Experiments using MICROGRIT SIC 1000 (10 μm silicone carbide) were carried out similarly.
For each composition, 13μ (1/2 mil), 25μ (1 mil)
mil) and 38μ (1.5 mil) thickness (wet)
The coating was carried out. Decorative sheets are generally gray due to the color of the silicone carbide. The results were as follows.

[Table] As can be seen from the table, the abrasion resistance was satisfactory, but the 10μ silicone carbide was less satisfactory than the 27μ silicone carbide.
The coloring of decorative sheets can be treated leniently. Example 7 In the experiment of Example 4, 60 g glass spheres (-325 screen size), 240 g glass spheres and 60 g CABOSIL L were substituted for the alumina particles, respectively.
Similar experiments were carried out on three compositions using -5 (silica aerosol with particle size milliμ). 13μ (1/2 mil), 25μ (1 mil) of each composition
and 38μ (1.5 mils) thick (wet). The results were as follows. Table 7 Type: Sufficient abrasion on taper tester ^* 60g glass 200 times 240g glass 200 times 60g silica aerosol <100 times *The equipment for measuring abrasion resistance described on pages 17-18 is a Taber abrasion tester. It is known as a testing machine. None of these samples exhibited satisfactory wear resistance. Example 8 In a fourth experiment, the same procedure was repeated using a coating composition in which microcrystalline cellulose was replaced with 6 g each of an anionic acrylic polymer (RETENE 420 - Hercules Powder Company) and 9 g carboxymethyl cellulose. A Taber abrasion test was performed on both samples and showed approximately 5% wear at 500 cycles.
This value was a satisfactory performance. However, the anionic acrylic polymer causes a slight emulsion in the laminate, indicating that this material can only be used satisfactorily in limited colors. Laminates using carboxymethyl cellulose as a binder for alumina have insufficient resistance to boiling water;
It did not pass NEMA standards. This material could only be used in low pressure, low pressure laminates. Example 9 To study the effects of silane, an experiment was performed using the following procedure. 1 g of γ-aminopropyltrimethoxysilane was mixed and dispersed with a 10% water-90% methanol solution. The minimum amount of liquid sufficient to wet the alumina powder was used. The dispersion was then mixed with alumina (MICROGRIT WCA30) with a particle size of 30μ.
100 g and the alumina and solution were mixed until the alumina was sufficiently moistened. 6μ (1/
Example 4 except applying a coating to the decorative sheet with a thickness of 0.6μ (0.025 mils) in the dry state
The procedure was repeated. The resulting laminate is also 6μ
(1/4 mil) thick coating (without silane)
A comparison was made with a laminate prepared according to Example 4. All laminates were press-finished to a mirror finish. The results of the abrasion resistance test are shown in Table 8 below. Table 8 Silane Without Silane Initial wear (number of times) 300 525 Final wear (number of times) 1075 1250 Wear value 687 887 The above results show that silane improves the effectiveness of the wear-resistant coating. Example 10 The effectiveness of improving the performance of the low pressure plate in the present invention was investigated. 250g water, 6.5g microcrystalline cellulose, 30g alumina 30μ and 2 drops TRITON
A slurry was prepared in the same manner as in Example 1 using -100.
Printed pattern paper that is not impregnated with slurry
It was coated as a 13μ (1/2 mil) wet layer (1μ (0.05 mil) dry) and dried for 3 minutes at 127°C (260°C). The sheet was then impregnated and dried twice to ensure complete impregnation. Then place the impregnated sheet on top of the particle panel.
6 at 14Kg/cm ² (200psi), 149℃ (300〓)
Pressed for a minute. For comparison, a low-pressure laminate with no abrasion-resistant coating applied to the upper surface of the decorative sheet was prepared. NEMA wear resistance tests were conducted on both samples. The results were as follows. Table 9 Abrasion resistant coating Coating None Initial wear 200 times No NEMA abrasion resistance 1050 times 150-200
From the above experimental results summarized in Table 9, it can be seen that the present invention also greatly improves the wear resistance of low-pressure laminates. Example 11 Repeat the procedure of Example 9, leaving a wet coating of 38 μm.
(1 1/2 mil) thick (4μ (0.15 mil) dry)
And so. Four experiments were conducted with varying amounts of silane, and the resulting laminates were subjected to NEMA abrasion testing. Initial wear was measured and the results are shown in Table 10 below. Table 10 Amount of silane/100g of alumina First wear, times 0 175 2 475 3 510 6 400 The above experiment shows that the effect of silane becomes substantial when the amount of silane reaches about 2% by weight based on the weight of alumina. This shows that there is no improvement. And actually 6%
In the experiment using 2% silane, the results were better than when no silane was included, but poorer than when using 2% silane. Example 12 The procedure of Example 9 was repeated to determine the initial abrasion resistance of the final laminate as a function of the temperature used to dry the coating on the decorative sheet. The patterned sheet was then coated with 4-5 kg (8-10
lb)/ream speed (dry coating 5μ (0.2 mil))
coated. The coatings of each sample were dried for 3 minutes at various temperatures as shown in Table 11 below. After drying, the coated sheet was kept at 21℃ (70℃) and 50% relative humidity.
Moisture equilibrium was reached with indoor air. The sheet was then conventionally impregnated with melamine-formaldehyde resin and laminated to a matte finish plate as usual. The results were as follows. Table 11 Furnace temperature, °C (〓) First wear, times 71 (160) 225 82 (180) 550 93 (200) 550 116 (240) 575 130 (265) 575 Example 13 6.5 parts by weight of AVICEL microcrystals Cellulose, 2 parts by weight of carboxymethylcellulose, 30 parts of 30μ
A slurry was prepared as disclosed in Example 1 using alumina and 250 parts by weight of water. Trace amounts of TRITON
X-100 was added. The resulting slurry was coated onto a decorative sheet (4μ (0.15 mil) dry thickness) using a Meyer bar coater at a rate of 2.5 kg (5.5 lbs.)/ream. The decorative sheet was then impregnated with melamine-formaldehyde resin to a resin content of 41.7%. After drying, the volatile components were reduced to 4.2%. The laminates with the coated decorative sheets were pressed using a standard lamination cycle and mirror finished laminate plates. The surface of the final product had photoselectivity. The laminate thus produced was compared to another mirror finish laminate produced in a conventional manner using a 9 kg (20 lb) overlay. A "sliding test" described below was conducted on both laminates. The laminate according to the invention has an initial wear of 325 times,
The NEMA wear value was 1021 times. The results compared in the sliding can friction test were as follows.

[Table] In both samples, pattern destruction started after about 30,000 cycles, but the conventional laminate showed that the surface started to become cloudy even after only 1,500 cycles, and in fact, the surface almost became cloudy within the first few hundred cycles. began to occur. Furthermore, conventional laminates are completely fogged before the first pattern failure (30,000 cycles) occurs. Compared to the prior art, the present invention provides greatly improved results that are considered a revolutionary development in the decorative laminate field. The present invention provides at least 400
A laminate without an overlay sheet is provided that has a NEMA abrasion resistance standard and a first wear point of at least 175 to 200 identical tests. In many laminate applications, the initial pattern wear, rather than the NEMA wear value, determines the acceptable life of the surface. For example, supermarket checkout counters, food service counters, cafeteria tables, and other commercial surfaces are subject to friction from sliding unglazed tableware, canned foods, fiberglass dishes, and the like. If a small area of the pattern disappears after a relatively short period of use, the surface becomes objectionable to the owner, especially if the pattern is irregular, resulting in expensive replacement. If the surface wears out gradually and uniformly over a long period of time, the period of wear out will be longer than the normal replacement cycle due to changes in fashion of about 3 to 5 years.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing a method for manufacturing a printed layer according to the present invention, FIG. 2 is a schematic sectional view showing an embodiment of a decorative sheet according to the present invention, and FIG.
The figure is a schematic cross-sectional view showing a laminate according to the invention. ... application of a thin layer of wear-resistant particles and binder,
...Drying at elevated temperature, ...Impregnation with thermosetting resin, ...Lamination step, 1..Unimpregnated base paper pattern sheet, 2..Printing ink pattern, 3.
... Al ₂ O ₃ particles combined with microcrystalline cellulose particles in a very thin resin layer, 4 ... Ultra-thin layer of Al ₂ O ₃ and microcrystalline cellulose binder, 5 ... Patterned sheet, 6 ...Core sheet.

Claims (1)

[Scope of Claims] 1. A decorative sheet impregnated with a thermosetting resin for use in producing a highly abrasion-resistant decorative laminate, the decorative sheet having an ultra-thin abrasion-resistant coating on its surface. , the ultra-thin abrasion resistant coating comprises (i) an abrasion resistant mineral of fine particle size in an amount sufficient to provide an abrasion resistant layer without visual disturbance; and (ii) the decorative sheet. the mineral binder in an amount sufficient to bind and stabilize the wear-resistant mineral to the surface of the sheet, compatible with the impregnating thermosetting resin and without visual disturbance; A decorative sheet impregnated with a thermosetting resin containing a mixture of. 2. The decorative sheet impregnated with a thermosetting resin according to claim 1, wherein the thermosetting resin for impregnating the decorative sheet is a polyester resin or a melamine resin. 3. A thermosetting resin-impregnated decorative sheet according to claim 2, wherein the decorative sheet has a decoration in the form of a printed design provided on the sheet directly below the ultra-thin abrasion resistant coating. Curable resin-impregnated decorative sheet. 4. In the thermosetting resin-impregnated decorative sheet according to any one of claims 1 to 3,
A thermosetting resin-impregnated decorative sheet in which the binder contains microcrystalline cellulose. 5. In the thermosetting resin-impregnated decorative sheet according to any one of claims 1 to 4,
A decorative sheet impregnated with a thermosetting resin, wherein the wear-resistant mineral includes alumina with a particle size of 20 to 50μ. 6. In the thermosetting resin-impregnated decorative sheet according to claim 1, the wear-resistant mineral is alumina with a particle size of 20 to 50μ, the binder contains microcrystalline cellulose, and the ultra-thin coating is 0.5~
8μ (0.02-0.3 mils) and the coating has a thickness of about 20
A thermosetting resin-impregnated decorative sheet containing 5 to 10 parts by weight of the microcrystalline cellulose based on 120 parts by weight of the alumina, and wherein the thermosetting resin for impregnating the decorative sheet is a melamine resin. 7. A decorative sheet impregnated with a thermosetting resin used to produce a highly abrasion-resistant decorative board, wherein the decorative sheet has an ultra-thin abrasion-resistant coating on its surface; The adhesive coating comprises (i) an abrasion resistant mineral of fine particle size sufficient to provide an abrasion resistant layer without visual disturbance; and (ii) a thermosetting material for impregnating said decorative sheet. the mineral binder and (iii) an aminosilane compound in an amount compatible with the resin and sufficient to bind and stabilize the wear-resistant mineral to the surface of the sheet without causing visual disturbances; A decorative sheet impregnated with a thermosetting resin containing a mixture of. 8. The decorative sheet impregnated with a thermosetting resin according to claim 7, wherein the thermosetting resin for impregnating the decorative sheet is a polyester resin or a melamine resin. 9. The thermosetting resin-impregnated decorative sheet according to claim 7, wherein the wear-resistant mineral is alumina with a particle size of 20 to 50μ, the binder contains microcrystalline cellulose, and the ultra-thin coating is 0.5~
8μ (0.02-0.3 mils) and the coating has a thickness of about 20
A thermosetting resin-impregnated decorative sheet comprising 5 to 10 parts by weight of the microcrystalline cellulose and 0.5 to 2.0 weight % of an aminosilane compound based on 120 parts by weight of the alumina. 10 A wear-resistant decorative laminate that passes NEMA abrasion resistance standards and can withstand 175 to 200 initial abrasions in the same test, comprising a support layer and a thermosetting resin impregnated laminated on the support layer. a decorative sheet, the decorative sheet having an ultra-thin abrasion resistant coating on an upper surface thereof, the ultra-thin abrasion resistant coating (i) being sufficient to provide an abrasion resistant layer without visual disturbance; (ii) compatible with the thermoset resin for impregnating the decorative sheet;
and a decorative laminate comprising a mixture with the mineral binder in an amount sufficient to bind and stabilize the wear-resistant mineral to the surface of the sheet without creating a visual hindrance. 11. The decorative laminate of claim 10, wherein said decorative sheet has decoration in the form of a printed design provided directly beneath said ultra-thin abrasion resistant coating. 12. The decorative board according to claim 11, wherein the thermosetting resin is a melamine resin. 13. The decorative board according to claim 12, wherein the binder includes microcrystalline cellulose. 14. The decorative laminate according to claim 13, wherein the wear-resistant mineral particles have a particle size of 20 to 20.
A decorative board made of 50μ alumina. 15. The decorative board according to claim 11, wherein the ultra-thin wear-resistant coating has a thickness of 1.3 to 8 μm.
(0.05-0.3 mil) decorative board. 16. The decorative board according to claim 13, wherein the support comprises a plurality of phenolic resin-impregnated paper sheets, the decorative sheet comprises a melamine resin-impregnated paper sheet, and the wear-resistant particles
The binder includes microcrystalline cellulose and the wear-resistant coating includes alumina particles of about 20 to 50 microns.
A decorative board comprising about 5 to 10 parts by weight or more of the microcrystalline cellulose based on 120 parts by weight of the alumina, and wherein the coating has a thickness of about 1.3 to 8 microns (0.05 to 0.3 mil). 17 A wear-resistant decorative laminate that passes NEMA abrasion resistance standards and can withstand 175 to 200 initial abrasions in the same test, comprising a support layer and a thermosetting resin impregnated laminated on the support layer. a decorative sheet, the decorative sheet having an ultra-thin abrasion resistant coating on an upper surface thereof, the ultra-thin abrasion resistant coating (i) being sufficient to provide an abrasion resistant layer without visual disturbance; (ii) compatible with the thermoset resin for impregnating the decorative sheet;
and (iii) a cosmetic comprising a mixture of said mineral binder and (iii) an aminosilane compound in an amount sufficient to bind and stabilize said wear-resistant mineral to the surface of said sheet without causing a visual disturbance. Board. 18. A decorative laminate according to claim 17, wherein said decorative sheet has a decoration in the form of a printed design provided directly beneath said ultra-thin abrasion resistant coating. 19. The decorative board according to claim 18, wherein the thermosetting resin is a melamine resin. 20. The decorative laminate according to claim 19, wherein the binder comprises microcrystalline cellulose. 21. The decorative board according to claim 19, wherein the wear-resistant mineral is alumina, and the alumina is chemically bonded to the melamine resin by aminosilane. 22. The decorative board according to claim 20, wherein the support includes a plurality of phenolic resin-impregnated paper sheets, the decorative sheet includes a melamine resin-impregnated paper sheet, and the wear-resistant particles
20 to 50 micron alumina particles, the binder includes microcrystalline cellulose, and the wear-resistant coating has an alumina particle size of about 20 to 50 micron.
A decorative board comprising about 5 to 10 parts by weight or more of the microcrystalline cellulose based on 120 parts by weight of the alumina, and wherein the coating has a thickness of about 1.3 to 8 microns (0.05 to 0.3 mil). 23. The decorative board according to claim 22, wherein the alumina is bonded to the melamine resin by aminosilane.