RU2346819C1 - Laminated material and method of its manufacture - Google Patents

Abstract

FIELD: technological processes; construction.

SUBSTANCE: method includes formation of upper layer comprising the following actions: the first side of substrate is impregnated with the first thermosetting resin; the first side of substrate is coated by layer of suspension containing the second thermosetting resin and mixture of particles resistant to wear, where mixture of wear resistant particles contains at least approximately 5 percents of elliptical lamellate wear resistant particles, to form composite; and composite is hardened to form hard composite.

EFFECT: resistance to wear, tear and damage of the first layer.

31 cl, 11 dwg

Description

LINKS TO RELATED APPLICATIONS

This application claims the priority of US Provisional Application No. 60 / 803,165, filed May 25, 2006.

BACKGROUND

1. Field of invention

The present invention relates to laminates. In particular, the present invention relates to a laminate comprising abrasion / wear resistant, scratch, scuff and damage resistant decorative high-pressure or low-pressure decorative surface layer with high transparency, and to a new method for forming this patentable laminate.

2. Background of the invention

Decorative laminates are well known and used, for example, as a facing material for walls, cabinet doors, desk covers, tables and other furniture, flooring materials, etc. Such laminates are often made from two or more base paper sheets impregnated with phenol-formaldehyde resin; from a decorative paper sheet, monochrome or with a printed pattern, impregnated with melamine-formaldehyde resin; and from a thin top sheet of alpha cellulose impregnated with melamine-formaldehyde resin.

The top sheet is designed to protect the decorative paper sheet from scratching, abrasion, scuffing and damage. For many years, top sheets have been used over decorative surfaces to protect against decay and tearing. According to the main technology used in the production of high pressure laminate (HPL), it was necessary to use a top sheet with particles (usually alumina) that were resistant to abrasion, which were previously applied in the paper manufacturing method, and which provided wear and abrasion resistance to the upper layer. Abrasion resistant particles are mixed with paper fibers during the papermaking process. Then the upper layer with pre-deposited particles is impregnated with a thermosetting resin and pressed at high temperature and under pressure with a base and decorative components in order to create a laminate.

The method used in this industry has recently been further developed, namely, abrasion resistant particles are applied to the top sheet during the impregnation. This method is called "liquid coating". In this method, a continuous roll of alpha cellulose paper is impregnated with a thermosetting resin and then coated with a liquid suspension of abrasion resistant particles / thermosetting resin. The upper layer made by the liquid coating method, after pressing, has significantly better transparency compared to that of the upper layer with pre-deposited particles obtained according to the previously discussed method. Transparency is an important quality due to which the decorative layer located under the top layer is more clearly visible, and, therefore, the final color of the laminate more precisely matches the color chosen by the designer for the decorative layer.

Despite the achieved level of transparency, the need to improve transparency remains, as well as the need remains to improve scratch resistance, wear resistance, resistance to tearing, damage and abrasion of laminates subjected to wear. This is especially important when using laminates as floor coverings, desk covers and tables. In General terms, a known method of manufacturing laminates is described as follows.

The roll paper is impregnated with a thermosetting resin, for example, melamine-formaldehyde resin. At least one side of the roll paper is coated with a slurry containing a certain size and quantity of small, dry and hard, abrasion resistant particles uniformly distributed over the entire wet surface of the resin on the roll paper. After that, the resin is dried, and coated with particles, impregnated paper, the so-called prepreg, is cut into sheets. At least one such sheet or continuous layer is placed in the form of an upper layer on the base and fastened with it.

The base may contain many conventional dry or impregnated prepregs of roll paper or paper sheets, respectively, not coated with abrasion resistant particles. The resin impregnated with the topmost of these rolls of paper or paper sheets may include a thermosetting resin such as melamine-formaldehyde resin, while the remaining paper rolls or paper sheets preferably comprise a thermosetting resin such as phenol-formaldehyde resin or phenol-urea-formaldehyde resin. Rolls of paper or a stack of paper sheets are laminated continuously or discontinuously, respectively, with a surface layer under high pressure and elevated temperature. Alternatively, the substrate may include a chipboard or fiberboard, wherein the top layer may be attached to the substrate by gluing or laminating under the influence of high temperature and pressure.

Attempts have been made to improve the abrasion resistance and wear resistance of these laminates by adding abrasion resistant particles during the manufacturing process of alpha-cellulose topcoat paper. Once added, abrasion resistant particles propagate through a layer of moist alpha-cellulose fibers along the mesh on a paper machine.

When applying this method, the particles are distributed more or less irregularly throughout the entire fiber layer. Some of these particles even pass through the grid. Thus, abrasion resistant particles are distributed unregulated or randomly over the upper layer. Using this known method, it is very difficult to achieve a uniform distribution of abrasion resistant particles on the surface of the paper. Since the best anti-abrasion effect is achieved as a result of uniform distribution of particles, in the prior art, laminates obtained by incorporating such a top sheet will provide uneven abrasion resistance.

In addition, in the prior art, the visibility of the decorative layer located under the top layer is reduced, and the laminate looks cloudy. Consequently, through the laminate, the decorative design is not clearly visible. The reason for this blurred image is the fact that abrasion resistant particles are on the paper when the paper is placed in the resin. The resin does not have enough time for sufficient impregnation to encapsulate each abrasion resistant particle; accordingly, air cavities appear around the abrasion resistant particles, distorting the light and causing the effect of milk fog.

SUMMARY OF THE INVENTION

The above-described disadvantages of the prior art are overcome by the upper layer formed by impregnating the substrate with a thermosetting resin and coating the substrate with a suspension containing a thermosetting resin and a mixture of abrasion resistant particles, in which the mixture of abrasion resistant particles comprises a certain percentage of elliptical lamellar particles of abrasion resistant particles, in which this percentage is determined by the degree of desired transparency. The resulting top layer exhibits higher transparency, scratch resistance, damage resistance and abrasion resistance. Additionally, to further improve the aforementioned characteristics, the top layer may be formed with additional layers of thermosetting resin that are applied to the composite after curing the composite containing the thermosetting resin and suspension. The top layer of the present invention combines liquid coating technology using flat, lamellar, abrasion resistant particles to create a laminate that, when pressed, would have better clarity and abrasion resistance, tear resistance and damage resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a flowchart showing a method of forming an upper layer;

figure 2 presents a schematic illustration of the upper layer formed by the method displayed in figure 1;

figure 3 presents a block diagram depicting a method of forming the upper layer;

Figure 4-7 is a schematic illustration of the upper layers formed by the method shown in Figure 3;

on Fig presents a flowchart depicting a method of forming a laminate;

Fig. 9 is a schematic illustration of a laminate formed by the method depicted in Fig. 8;

figure 10 presents a photograph of abrasion resistant particles from the prior art; and

figure 11 presents a photograph of abrasion resistant particles of an elliptical lamellar shape.

DETAILED DESCRIPTION OF THE INVENTION

As stated above, until now there has not been a satisfactory way to avoid the above problems. However, in accordance with the present invention, it has become possible to solve the above problems and to implement a method for manufacturing a decorative thermoset laminate having improved characteristics, including improved transparency and improved abrasion resistance, resistance to scuffing and damage resistance. The method includes forming an upper layer containing a substrate impregnated with a thermosetting resin and coated with a suspension, the suspension containing a thermosetting resin and elliptical, plate-shaped particles that are resistant to abrasion. Then, the resulting composite is cured in order to obtain a solid composite. Additionally, this method may include adding to the solid composite at least one or more additional layers of thermosetting resin.

The substrate may include traditional topcoats. Thus, the substrate may include, for example, at least one of the materials: paper, glass gun, mica, etc., and may include one or multiple layers of these materials.

The thermosetting resin used to impregnate the substrate, the thermosetting resin used to form the slurry, and the additive thermosetting resin (s) can include a wide variety of thermosetting resin compositions and can be identical or different in composition. The thermosetting resin may include thermosetting resins traditionally used in laminate production, which include, for example, at least one of the resins: phenol-melamine, melamine-formaldehyde, phenol-urea-formaldehyde-melamine, polyester-melamine, urea-formaldehyde, polyurethane epoxy resin melamine and the like

Accordingly, the thermosetting resin may include low pressure and high pressure chemicals, depending on whether you want to obtain low pressure laminates or high pressure laminates. In general, high pressure chemicals have a low molar ratio, and low pressure chemicals have a high molar ratio. The molar ratio can vary widely and is a proportion between the concentration of the cross-linking reagent, for example formaldehyde, and the concentration of the thermosetting reagent, i.e. melamine, in the thermosetting resin, where the molar ratio is selected so as to give the laminate certain desired characteristics depending on the purpose of the laminate.

Additionally, the thermosetting resin used in the method disclosed herein may contain certain additives designed to enhance the preferred properties. For example, additives may include at least one of a substance: plasticizers that control the flexibility of the surface layer; saturating reagents that increase transparency; catalysts that control flexibility and promote curing of the surface layer; release agents involved in the manufacturing process; release agents that reduce the sticking or jamming of paper in a bale; additives that prevent damage and tearing, reduce the friction force on the surface of the surface layer. Additives may be added at various points in the process disclosed herein.

The suspension applied to the thermosetting resin, which is impregnated with the substrate of the upper layer, contains a thermosetting resin and abrasion resistant particles. The thermosetting resin included in the suspension may contain the thermosetting resins described above, the thermosetting resin impregnating the substrate may include compositions that are identical to or different from the thermosetting resin included in the suspension, both with respect to the specific reagents used and the amount of reagents used in the composition.

In addition to the thermosetting resin, the suspension includes abrasion resistant particles having an elliptical plate shape. Abrasion resistant particles can include many different substances, where exemplary substances include, for example, at least one of quartz, alumina, and silicon carbide. An important effect on the final result is exerted by the size and shape of the particles. If the particles are too large, the surface of the laminate will be rough and unpleasant. On the other hand, too small particles can give only very little resistance to abrasion. Accordingly, in an exemplary embodiment, the sizes of the abrasion resistant particles are in the range of from about 1 to about 100 micrometers.

As stated previously, abrasion resistant particles are elliptical, lamellar in shape. An exemplary abrasion resistant particle according to the present invention has an elliptical hexagonal plate shape similar to that shown in FIG. 11.

In traditional upper layers, it is generally accepted to use jagged, crystalline structures and spherically shaped abrasion resistant particles, as shown, for example, in FIG. 10. In the process of pressing, such jagged, spherical shapes leave significant points on the surface of the laminate. However, the elliptical relatively flat, plate-shaped abrasion resistant particles of the present invention create a smoother flat surface during the compaction process. Such a smooth surface increases resistance to scratching and damage to the upper layers. In particular, the abrasion resistant lamellar particles are visually superior to the spherical fused type shown in FIG. 10. In an exemplary embodiment, the elliptical, abrasion resistant particles have a width to thickness ratio of about 5: 1, meaning that the elliptical particles are wide but thin. Therefore, it is easier to see through abrasion resistant lamellar particles than through spherical particles that are abrasion resistant.

The shape of the abrasion resistant particles may also affect the life of the press plate. The standard spherical particles used in traditional upper layers quickly cause premature wear of the press plate during the pressing of the upper layer, since the abrasion resistant particles can act like sandpaper. However, the abrasion resistant particles of the present invention present in the upper layer, since they are relatively small, that is, their size ranges from about 1 micrometer to about 100 micrometers, have a plate shape, are less capable of causing premature wear to the plate.

Despite the benefits of using abrasion-resistant lamellar particles, if additional wear resistance is required, in addition to the relatively flat, elliptical, lamellar-shaped abrasion-resistant particles discussed earlier, the suspension may also contain abrasion-resistant crystalline particles, it being assumed that to achieve the desired characteristics of the final product, any combination of shapes, sizes, and concentrations of abrasion resistant particles can be used. However, in an exemplary embodiment, it is assumed that the suspension contains at least about 5 percent abrasion resistant lamellar particles, where the percentage is determined from the total amount of abrasion resistant particles contained in the suspension.

An illustrative method used to form the top layer and laminate according to the present invention is described with reference to FIG. 1. Referring to FIG. 1, the method includes preparing a suspension, the concentration of abrasion resistant particles in which is from about 1 percent to about 50 percent, determined from the total concentration of the suspension, in which at least about 5 percent of the abrasion resistant particles are elliptical where the percentage is determined from the total amount of abrasion resistant particles contained in the suspension. The method further includes applying a thermosetting resin to the substrate, and then, while the substrate has not yet dried after applying the thermosetting resin, applying the suspension to the substrate. In a preferred embodiment, the substrate includes paper containing a continuous roll of alpha cellulose and having a weight of from about 10 to about 100 grams per square meter.

The method of applying the suspension to impregnate the substrate may be different. However, in a preferred embodiment, the method may comprise spraying the suspension on a substrate under pressure, as is usually the case with ATM spray systems, and / or using a suspension tank and a rotating metering roller with a rough surface, placed inside or above the tank, as usually happens with a deep print. In intaglio printing, the substrate passes through the reservoir or into the reservoir, and the slurry continuously fed through the metering roller is evenly distributed across the substrate.

More specifically, in an ARP spray system, the suspension is continuously sprayed and an adjacent set of smoothing, rotating rollers is used. The substrate comes into contact with the suspension when it is sprayed from the sprayer. The substrate is then passed through smoothing, rotating rollers that remove excess slurry.

The intaglio printing system uses a rotating roller in which open cells are cut. The rotating roller contains a suspension that is continuously pumped into the cells. When the substrate passes under a rotating roller, the suspension is applied to the substrate.

In this description of the invention, a combination of two systems is considered, namely, a device using a sprinkler, rollers and open cells.

The device may also include a squeegee plate, designed to ensure uniform supply of suspension along the surface of the metering roller.

Other devices may be used to apply the slurry to the wet substrate. For example, an electrostatic coating can be used, along with, for example, reverse roll coating technology. It is also possible to charge the abrasion resistant particles by friction and then add the suspension to the thermoset resin layer on the wet substrate. A similar charge can be obtained, for example, by rubbing particles on a Teflon surface.

Once the composite containing the thermoset resin impregnated substrate and suspension is formed, the composite is dried and cured. After curing, the concentration of abrasion resistant particles in the coating is from about 0.1 grams per square meter (g / m ² ) to about 50 g / m ² . After drying and curing, the solid composite can be cut to be used as the top layer in the formation of the laminate.

Turning to FIG. 2, the top layer 10 can be formed by the method disclosed previously with reference to FIG. 1. The top layer 10 includes a suspension layer 24 and a substrate 26. The suspension layer 24 contains a thermosetting resin 12 and a mixture of abrasion resistant particles 14. Additionally, the substrate 26 contains a roll of alpha cellulose 16 and a thermosetting resin 18, with the thermosetting resin 18 and thermosetting resin 12 may be identical or different from each other.

FIG. 3 shows a method of forming another exemplary top layer, wherein the method of FIG. 3 is identical to that of FIG. 1, but includes applying one or more additional thermosetting resin layers and / or suspension layers to a cured composite formed according to the method of FIG. 1, wherein the additional thermosetting resin layers and / or the additional suspension layers may include the same or different thermosetting resin (s) and / or suspension layers used for Creating uncured composite. That is, after drying and curing the initial composite and before cutting it, one or more additional thermosetting resin layers and / or suspension layer (s) can be added to the cured composite. The resulting composite, now already containing additional layer (s) of thermosetting resin and / or layer (s) of suspension, can be re-dried and cured. The resulting final solid composite can then be cut or rewound to be used as a top layer in the formation of the laminate. It is contemplated that one or more additional thermosetting resin layers may be applied to any of the suspension layers, a substrate, or to a previously applied additional thermosetting resin layer and / or an additional suspension layer. Additionally, in a particularly preferred embodiment, an additional layer of the suspension is preferably applied to at least one of the following layers: the initial layer of the suspension, that is, the suspension layer that directly covers the substrate; on another additional layer of the suspension or on an additional layer of thermosetting resin, in which the additional layer of the suspension is preferably applied to the same side of the substrate as the initial layer of the suspension, but not directly, that is, when the laminate is formed, the additional layer of the suspension will preferably not be located between the substrate and the base.

An exemplary method of forming an upper layer containing one or more additional layers of thermosetting resin involves impregnating the substrate with a layer of thermosetting resin in an amount of from about 5 to about 250 g / m ² and then applying a suspension layer to the thermoset resin-impregnated substrate, an amount of from about 5 to about 250 g / m ² . The thermosetting resin layer and suspension are dried and cured in due time and at the proper temperature (from about 80 degrees Celsius to about 200 degrees Celsius), to achieve a volatile content of from about 2 percent to about 10 percent (measured at 165 degrees Celsius for 5 minutes). In this drying process, a solid composite is formed. After drying or partially during drying, one or more additional layers of thermosetting resin and / or layers of suspension can be added to the composite, while such additional layers of thermosetting resin and / or layers of suspension can be applied directly to the dried layer of the suspension, directly to the substrate, and / or directly onto an adjacent additional resin layer. After applying additional layers, the composite is dried at the proper time and at the proper temperature (from about 80 degrees Celsius to about 200 degrees Celsius), to achieve a volatile content of about 2 percent to about 10 percent (measured at 165 degrees Celsius for 5 minutes )

Exemplary upper layers obtained by the method of FIG. 3 are shown in FIGS. 4-7. Referring to FIG. 4, the top layer 100 comprises a substrate 102 impregnated with a thermosetting resin 104 and having a suspension layer 106 consisting of abrasion resistant particles 108 and a thermosetting resin 110 applied to the top of the substrate 102. In this embodiment, the top layer 100 also includes a layer of thermosetting resin 112 deposited on the top of the slurry layer 106. Referring to Figure 5, the top layer 120 contains a substrate 122 impregnated with a thermosetting resin 124 and having a layer of slurry 126, consisting of abrasion resistant particles 128 and thermosetting a jet 130 located on the upper part of the substrate 122. In this embodiment, the upper layer 120 also includes a thermosetting resin layer 132 located on the lower side of the substrate 122.

Referring to FIG. 5, the top layer 140 includes a substrate 142 impregnated with a thermosetting resin 144 and having a suspension layer 146 consisting of abrasion resistant particles 148 and a thermosetting resin 150 located on the upper side of the substrate 142. In this embodiment, the upper layer 140 also includes two additional layers of thermosetting resin 152 and 154, placed one on top of the other and on top of the suspension layer 146.

Referring to FIG. 7, the top layer 160 includes a substrate 162 impregnated with a thermosetting resin 164 and having a suspension layer 166 consisting of abrasion resistant particles 168 and a thermosetting resin 170 located on the upper surface of the substrate 162. In this embodiment, the upper layer 160 also includes a resin layer 172 and a suspension layer 174, the suspension layer 174 comprising abrasion resistant particles 176 and a thermosetting resin 178, in which the abrasion resistant particles 176 and thermosetting resin 178 may be identical or different from the corresponding abrasion resistant particles 168 and thermosetting resin 170.

In addition to the method of forming a new top layer, the present invention also provides a method for manufacturing a decorative thermoset laminate having a wear resistant top layer in which the top layer is formed according to the above methods. That is, as shown in FIG. 8, the top layer formed by any of the above methods can be compressed at a temperature of from about 200 degrees Fahrenheit to about 500 degrees Fahrenheit and under pressure from about 100 psi to about 1800 pounds per square inch, together with the base and decorative sheets, with the aim of manufacturing given as an example of a decorative laminate 200, shown in Fig.9. Referring to FIG. 9, an exemplary laminate 200 comprises a top layer 201 consisting of a substrate 202 impregnated with a thermosetting resin 204 and having a suspension layer 206 placed on top of it. The layer of suspension 206 contains abrasion resistant particles 208 and thermosetting resin 210. B in addition to the top layer 201, the laminate 200 also contains a decorative sheet 212 and a base 214. Preferably, the laminate 200 is pressed upward with a layer of slurry 206 to create a protective layer on the surface of the laminate 200 that provides wear resistance and improved performance ate scratch, damage and scratch resistance.

Although the present invention has been described with reference to the drawings, it is understood that the present invention is not limited to them. Of course, the present invention should include all modifications and changes to the present invention that can be made by a person skilled in the art.

Claims (31)

1. A method of manufacturing a decorative laminate with a top layer resistant to abrasion, scuffing, damage, and the method includes forming the upper layer, and the method of forming the upper layer includes the following:
the first side of the substrate is impregnated with a first thermosetting resin;
the first side of the substrate is coated with a slurry layer containing a second thermosetting resin and a mixture of abrasion resistant particles, wherein the mixture of abrasion resistant particles contains at least about 5% elliptical plate-shaped abrasion resistant particles to form a composite; and the composite is cured to form a solid composite. 2. The method according to claim 1, in which the mixture of abrasion resistant particles also contains abrasion resistant particles of crystalline form. 3. The method according to claim 1, in which the first thermosetting resin contains at least one of the following resins: melamine-formaldehyde resin, phenol-formaldehyde resin and phenol-urea-formaldehyde resin. 4. The method according to claim 3, in which the second thermosetting resin contains at least one of the following resins: melamine-formaldehyde resin, phenol-formaldehyde resin and phenol-urea-formaldehyde resin. 5. The method according to claim 1, wherein the substrate comprises alpha-cellulose-based paper. 6. The method according to claim 1, in which the mixture of abrasion resistant particles includes at least one of the following substances: quartz, alumina and silicon carbide. 7. The method according to claim 1, in which the elliptical plate-shaped abrasion resistant particles have an average size of from about 1 to about 100 microns. 8. The method according to claim 1, in which the elliptical plate-shaped abrasion resistant particles are in the form of hexagons. 9. The method according to claim 1, in which the elliptical plate-shaped abrasion resistant particles have a width to thickness ratio of about 5: 1. 10. The method according to claim 1, further comprising preparing a suspension layer, in which the suspension layer contains from about 1 to about 50% of abrasion resistant particles. 11. The method according to claim 10, in which the impregnation is the impregnation of the substrate with the first thermosetting resin in an amount of from about 5 to about 250 g / m ² . 12. The method according to claim 11, in which the coating on the first side of the substrate includes applying to the substrate a layer of suspension in an amount of from about 5 to about 250 g / m ² . 13. The method according to claim 1, further comprising placing a decorative sheet between the top layer and the base sheet to create a single product and the impact on the product with high temperature and pressure. 14. The method according to claim 1, in which the method of forming the upper layer further includes the steps of:
at least one or more additional layers of thermosetting resin and one or more additional layers of suspension are added to the solid composite to form a second composite; and cure the second composite. 15. The method according to 14, in which an additional layer of thermosetting resin is applied to the suspension layer. 16. The method according to clause 15, in which an additional layer of thermosetting resin is applied to the side of the substrate opposite to the layer of suspension. 17. The method according to 14, further comprising placing a decorative sheet between the upper layer and the base sheet in order to form a single product and the impact on the product with high temperature and pressure. 18. The method according to 14, in which at least one or more of the elliptical plate-shaped abrasion resistant particles has the shape of a hexagon. 19. The method according to 14, in which the elliptical plate-shaped abrasion resistant particles have a width to thickness ratio of about 5: 1. 20. The method according to 14, further comprising preparing a suspension layer, in which the suspension layer contains from about 1 to about 50% of abrasion resistant particles. 21. The method according to claim 20, in which the impregnation is the impregnation of the substrate with the first thermosetting resin in an amount of from about 5 to about 250 g / m ² . 22. The method according to item 21, in which the coating of the first side of the substrate is a coating of the substrate with a suspension in an amount of from about 5 to about 250 g / m ² . 23. A laminate formed by the method of claim 14. 24. The laminate formed by the method according to claim 1. 25. A decorative laminate having increased transparency, wear resistance, resistance to damage, resistance to scuffing, and the decorative laminate contains a top layer containing
a substrate impregnated with a first thermosetting resin; and
a slurry layer containing a second thermosetting resin and a mixture of abrasion resistant particles, where the mixture contains at least about 5% elliptical lamellar particles. 26. The decorative laminate of Claim 25, wherein the mixture also includes crystalline abrasion resistant particles. 27. The decorative laminate of Claim 25, wherein the at least one or more elliptical plate shaped abrasion resistant particles has a hexagon shape. 28. The decorative laminate of Claim 25, wherein the mixture of abrasion resistant particles comprises at least one of the following: quartz, alumina, and silicon carbide. 29. The decorative laminate of Claim 25, wherein the top layer comprises abrasion resistant particles in an amount of from about 0.1 g / m ² to about 50 g / m ² . 30. The decorative laminate of claim 25, wherein the abrasion resistant particles have a size of from about 1 to about 100 microns. 31. The decorative laminate of claim 25, wherein the top layer further comprises at least one of the following: one or more additional layers of thermosetting resin and one or more additional layers of suspension.

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