RU2100210C1 - Sheet with ornament used in production of decorative laminated material, decorative laminated material and method for manufacture such material - Google Patents

Abstract

FIELD: production of decorative laminated material. SUBSTANCE: method involves using preliminarily hardened materials in the form of particles of impregnating resin in conjunction with basic binding material, as well as, preferably, particles of wear-resistant mineral. Protective surface covering may be applied in the form of thick layer to impart resistance to pressing through force and produce the feeling of depth. Impregnating resin and materials in the form of preliminarily hardened particles have equal refraction coefficient to provide excellent covering transparency and final sharpness of lower sheet with ornament. EFFECT: increased efficiency, wider operational capabilities and enhanced reliability in operation. 47 cl, 2 tbl

Description

 The invention relates to sheets with ornaments used in the production of decorative laminated materials, to decorative laminated materials suitable for the upper parts of trading tables and counters, wall panels, floor surfaces, upper parts of desks, in particular for laminated materials obtained using high pressure, and to methods for the manufacture of sheets with ornament and layered materials.

 A known sheet with an ornament for use in the manufacture of decorative laminated material containing a thermoset resin impregnated sheet of paper with a protective layer placed on top of a sheet of paper (UK patent N 1399592).

 From the same UK patent N 1399592, a decorative laminate is known comprising a substrate with a decorative top layer formed from a cured and bonded ornamental paper impregnated with a thermosetting resin and a protective layer placed on top of the decorative layer.

 In addition, this UK patent N 1399592 discloses a method for manufacturing an ornamental sheet used in the manufacture of decorative laminate, which consists in applying a protective layer to an ornamental sheet and impregnating the thermosetting resin with the ornamental sheet.

 Finally, from British Patent No. 1399592, a method for manufacturing a decorative laminate is known, comprising assembling a substrate and a thermoset resin impregnated with a decorative top layer with a protective layer placed on top of it, applying heat and pressure to the assembly with the possibility of spreading and at least partial curing thermosetting resin.

 In a known sheet with an ornament used in the production of decorative laminate, decorative laminate, and also when using known methods for their manufacture, a quality sufficient for commercial purposes is not achieved, i.e. cracks in the products, creasing, products are possible, they are characterized by excessive stiffness, insufficient transparency, have a high cost and often have a dirty look. In addition, the well-known ornamental sheet and decorative laminate do not have abrasion resistance that meets the requirements of NAEP (National Association of the Electrotechnical Industry).

 The basis of the invention is the task of creating a sheet with an ornament used in the production of decorative layered material, and decorative layered material with an ultra-pure, creating a sense of depth appearance, resistance to bursting and characteristic of abrasion resistance, satisfying the requirements of NAEP, and having a thick protective coating on a sheet with an ornament, and also develop methods from the manufacture.

 This problem according to one aspect of the invention is achieved by the fact that in an ornamental sheet for use in the production of decorative laminate containing a thermosetting resin impregnated paper sheet with a protective layer placed on top of the paper sheet, according to the invention, the protective layer is essentially transparent and contains particles of the previously cured thermosetting resin, and the refractive index of the particles of the pre-cured resin is essentially the same as the refractive index impregnated thermosetting resin.

 It is advisable that the protective layer contains particles of mineral material of small sizes having a Mohs hardness of at least 7 in the matrix of the thermosetting resin. Preferably, the protective layer contains the starting binder material.

 It is useful that the particles of the pre-cured resin and the impregnating thermosetting resin represent the same resin.

 Preferably, the resin is a polyester, melamine or urea resin.

 It is advisable that the mineral particles of the protective layer have an average particle size of not more than 50 microns.

 Preferably, the protective binder starting material comprises microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.

 It is useful that the transparent protective layer has a thickness of 2-3 ml, preferably 3 ml.

 This problem according to another aspect of the invention is solved by the fact that in a decorative laminate containing a substrate with a decorative top layer formed from a cured and bonded with a substrate sheet of ornamented paper impregnated with a thermosetting resin, and a protective layer placed on top of the decorative layer, according to the invention, is protective the layer is abrasion-resistant, substantially transparent and contains particles of a pre-cured thermosetting resin, with a preliminary index of refraction of particles the flax cured resin is essentially the same as the refractive index of the impregnating thermosetting resin.

 Preferably, the protective layer contains particles of mineral material of small sizes having a Mohs hardness of at least 7 in the matrix of the thermosetting resin.

 It is advisable that the protective layer contains the original binder material.

 It is useful that the particles of the pre-cured resin and the thermosetting resin represent the same resin.

 Preferably, the resin is a polyester, melamine or urea resin.

 Preferably, the mineral particles of the protective layer have an average particle size of not more than 50 μm.

 It is advisable that the starting binder material of the protective layer contains microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.

 It is useful that the protective layer has a thickness of 2-3 ml, preferably 3 ml.

 It is desirable that the substrate is formed of wood, but it is possible that the substrate is made of wood veneer.

 Preferably, the decorative laminate would be a low pressure laminate, the resin being a polyester or melamine resin.

 It is advisable that the decorative laminate be a high pressure laminate, the resin being a melamine or urea resin, the substrate would be heart-shaped sheets impregnated with a resin, which is preferably a phenol-aldehyde resin.

Most preferably, the protective layer contains:
(1) 5 to 30 wt. including particles of a mineral selected from the group consisting of alumina, silica and mixtures thereof;
(2) 1 5 parts by weight a starting binder material selected from the group consisting of microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, and mixtures thereof;
(3) particles of pre-cured resin, taken in an amount from an equal number of particles of a mineral to an amount six times the number of particles of a mineral;
(4) a thermosetting resin with a refractive index substantially equal to the refractive index of the pre-cured resin particles, taken in an amount sufficient to form a constant matrix for the mineral particles and for the pre-cured resin particles.

 It is advisable that essentially all of the particles of the pre-cured resin have sizes less than 250 microns.

 It is desirable that the protective layer contains 100 parts by weight of particles of pre-cured resin up to 100 wt.h. particles of a finely dispersed colorless, abrasion resistant mineral material with a Mohs hardness of at least 7 and an average particle size of at least 50 μm and the starting binder in an amount sufficient to hold the particles of mineral material and particles of pre-cured resin on the sheet surface paper with ornament.

It is useful that the protective layer contains 0.212-0.282 g / m ² particles of pre-cured melamine resin.

It is possible that the transparent protective layer has a thickness corresponding to 0.085-0.113 g / m ² particles of pre-cured resin and particles of mineral material.

 This problem according to another aspect of the invention is solved by the fact that in the method of manufacturing a sheet with an ornament used in the manufacture of decorative laminated material, which consists in applying a protective layer to the sheet with the ornament and impregnating the sheet with the ornament with a thermosetting resin, according to the invention, a protective layer containing particles pre-cured thermosetting resin, and the refractive index of the particles of the pre-cured resin is essentially the same as the refractive index matrices of impregnating thermosetting resin.

 It is preferable to use a protective layer containing small mineral particles having a Mohs hardness of at least 7 in the thermosetting resin matrix.

 It is useful to use a protective layer containing the starting binder material.

 It is desirable to use the same resin as the particles of the pre-cured resin and the thermosetting resin.

 It is advisable to use a resin, which is a polyester resin, melamine resin or urea resin.

 It is possible to use mineral particles of the protective layer with an average particle size of not more than 50 microns.

 It is preferable to use the starting binder material of the protective layer containing microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.

 It is desirable that the transparent protective layer has a thickness of 2-3 ml, preferably 3 ml.

 It is advisable that the protective layer was applied to the sheet with the ornament and the thermosetting resin ornament was impregnated in two separate stages, and the protective layer was first applied to the ornamented sheet by applying a wet layer of particles of the previously cured thermosetting resin and the starting binder material, and the wet layer was dried , and then impregnated with a sheet of ornaments with thermosetting resin.

 It is possible that when applied to a sheet with an ornament of the protective layer, use a wet layer containing mineral particles.

 It is useful that applying a protective layer to the sheet with the ornament and impregnating the sheet with the thermosetting resin ornament is carried out in one step, and first a mixture of thermosetting resin and particles of pre-cured thermosetting resin having a viscosity of no more than 250 cP is prepared, and this mixture is applied to the sheet with with an ornament overlaid on a sheet with an ornament a layer of particles of a previously cured resin and at the same time impregnating a sheet with an ornament with a thermosetting resin, and then the coated and impregnated ones were dried about a sheet with an ornament.

 Preferably, the mixture includes mineral particles of small sizes and the starting binder material.

 This problem according to the last aspect of the invention is solved by the fact that in the method of manufacturing a decorative layered material, which consists in assembling a substrate and a decorative top layer impregnated with a thermosetting resin with a protective layer placed on top of it, applying heat and pressure to the assembly with the possibility of spreading and at least as the thermosetting resin is partially cured, according to the invention, a protective layer containing a cured thermosetting resin, about azovannuyu particulate pre-cured resin particles and the refractive index precured resin is substantially the same as the refractive index of the thermosetting resin impregnating the at least partially cured form, and the protective layer is transparent and resistant to abrasion.

 Preferably, the cured thermosetting resin includes small mineral particles having a Mohs hardness of at least 7 in the matrix of the thermosetting resin, the thermosetting resin being compatible with the thermosetting resin, which is impregnated with a decorative topcoat.

 It is advisable that the cured thermosetting resin includes a starting binder.

 It is useful that the same resin be used as particles of the pre-cured resin and the thermosetting resin.

 It is possible to use a resin which is a polyester, melamine or urea resin.

 It is desirable to use mineral particles of the protective layer with an average particle size of not more than 50 microns.

 It is preferable to use the starting binder material of the protective layer containing microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.

 It is useful that the transparent protective layer has a thickness of 2-3 ml, preferably 3 ml.

 It is possible that the resulting laminate was a low pressure material, with polyester or melamine resin being used.

 It is advisable that the resulting layered material be a high pressure material, using melamine or urea resin, and the substrate is made of heart-shaped sheets impregnated with a resin, which is preferably a phenol-aldehyde resin.

 The essence and advantages of the present invention will be more apparent from the following detailed description of various embodiments of the invention.

 One of the key features of the present invention is the use of particles of a pre-cured thermosetting resin, which are formed from a resin having the same or essentially the same refractive index as the uncured or partially cured resin used as a binder for laminate, which is used in the process of forming the layered material after the latter has become thermoset during the formation of the layered material. The term "pre-cured" means that the curing or embracing of the resin particles has reached either the maximum extent possible, or at least the curing stage, where its melt viscosity is high enough to prevent the dissolution of these particles in the liquid resin used in as a binder for laminated plastics, and / or from melting and flow under normal conditions, the formation of a layered structure and the resulting undesirable impregnation of paper below, for example, paper with ornament volume during pressing / lamination to form a layered material.

 The invention uses the principle that the material having the closest refractive index with the cured resin used as a binder for laminates is a cured resin used as a binder for laminated plastics. Therefore, in the case when the resin used as a binder for laminated plastics, the ornamented sheet is a melamine-formaldehyde resin (hereinafter “melamine” resin), as is the case in typical cases, the main material in the form of particles from which it is formed protective coating layer, there will be particles of pre-cured melamine resin.

 Melamine resin is a typical resin used as a binder for laminated plastics, and it is usually used to saturate / impregnate an ornamental sheet and a covering sheet in the process of producing decorative high-pressure laminated materials that meet NAEP standards. Therefore, melamine resin is a preferred resin used as a binder for laminates for use in the top layer or layers of the present invention.

 Therefore, the particles of the pre-cured thermosetting resin are also preferably referred to as melamine resin. However, other resin systems are possible, for example polyesters, urea-formaldehyde, dicyanodiamide-formaldehyde, epoxides, polyurethane, curable acrylic compounds and mixtures thereof. Thus, the material from the particles of pre-cured polymers can be selected from melamine resin, polyester, epoxide, cured acrylic compound, and the like. as well as mixtures thereof.

 Under certain conditions and in order to achieve special effects, it is also possible to use some incompatible mixtures, for example, cured polyester resin particles or polyurethane resin particles together with cured melamine resin particles, with liquid melamine resin used as a binder for laminates, however usually the cured resin is the same as the liquid resin used as a binder for laminates, and any particles of incompatible cured resin are present dissolved only in small quantities.

 It is also possible to use mixtures of particles of pre-cured resin that are pre-cured to various degrees of setting, and even a small number of resin particles that are still able to partially dissolve in liquid melamine resin and thus have the ability to melt and flow into the underlying paper; however, the number of such less cured particles should not be so large that the desired product will not be obtained, that is, the final laminate should have a transparent protective surface layer, mainly formed from a pre-cured resin. However, in those cases where the transparent surface layer is very thin, the abrasion resistant mineral particles can be up to about 50% or more.

 With the exception of the transparent protective layer covering the ornamental sheet, the laminate of the present invention is conveniently made in accordance with standard practice, therefore, its conventional construction is acceptable, for example, it may include 2-8 inner sheets formed by kraft paper impregnated with phenol-aldehyde resin with an ornamented sheet overlaid with melamine resin, plus a protective layer according to the invention over the ornament layer. The final laminate is made in the usual way, such as folding into a stack of inner sheets in a suitable press, applying a decorative sheet coated with a protective layer over them and exposing the resulting assembly to sufficient heat and pressure applied between the two plates of the compression dies for a sufficient time to obtain the desired decorative laminate. The pressing conditions of both the high pressure laminate and the low pressure laminate are standard and well known.

The coating of a thick transparent protective surface layer mainly includes particles of a pre-cured thermosetting resin together with the starting binder and (optionally, but preferably) a small amount of abrasion resistant mineral with a relatively small particle size, preferably with an average particle size in the range of 0.5 -50 μm, preferably about 1-30 μm, and most preferably with an average particle size of about 1 μm. A typical protective surface layer of this type will include 15-20 lb / rm (0.212-0.282 g / m ² ) of pre-cured melamine resin particles and 6 lb / rm (0.085 g / m ² ) of Al ₂ O ₃ particles. Particles of abrasion resistant mineral are preferably present in an amount sufficient to partially cover the larger particles of the pre-cured resin, which can reach 250 microns, but preferably have a maximum size of 100 microns. The mineral particles must have a hardness of at least 7 on the Mohs scale, these particles are preferably alumina or a mixture of alumina and silica, although the mineral particles may include zirconium oxide, cerium oxide, hard glass granules, silicon carbide and diamond dust. Significant amounts of other materials, such as flocculated fiber deposits, etc., should be avoided. as they reduce transparency.

The starting binder material can be any system-compatible material that holds the coating of the protective layer in place on the top surface of the ornamental sheet before completing the process of forming a layered structure, including a plurality of resin-based adhesives that are compatible with the selected resin system used as a binder for laminated plastics, a highly viscous or thick, partially cured resin or any other materials that are referred to as suitable as binder materials erialov in accordance with ARP ^® technology such as sodium alginate, fumed silica, microcrystalline cellulose or mixtures thereof, for example, a mixture of a large amount of microcrystalline cellulose with a small amount of carboxymethylcellulose (CMC).

Another typical product of the present invention has a much thinner protective surface layer corresponding to a thickness of 6-8 lb / rm (0.085-0.113 g / m ² ) of solid, which includes approximately equal amounts of pre-cured resin particles and mineral particles. This is an ARP ^® type product containing only about half the amount of mineral particles compared to the ARP ^® laminate but has complete abrasion and wear resistance along with improved tool wear and reduced wear on the compression die plates.

A protective coating can be applied to a sheet with an ornament in different ways. These include a two-stage method similar to the ARP ^® method, a one-stage method, the same as the ARP ^® method, a transfer method, and also a method of applying a varnish in which the composition of the protective surface layer is applied directly onto a wood veneer or similar material and then pressed.

 In a preferred form for use in the two-step method, the coating composition is prepared from a mixture of small alumina particles or other abrasion resistant particles, preferably with an average particle size of about 1 30 microns, pre-cured resin particulate material with a maximum particle size of 250 microns and preferably with a maximum particle size 100 microns, as well as fewer particles of microcrystalline cellulose, all of which are dispersed in a stable aqueous suspension. The abrasion resistant material is alumina particles of such a small size that they do not interfere with the visual effects in the final product, and microcrystalline cellulose particles are used as the preferred starting binder material. It will be understood that the starting binder material must be compatible with the resin system used in the process of forming a layered structure (usually melamine resin) or, in the case of certain low pressure laminate materials with a polyester resin system, microcrystalline cellulose performs this function and also stabilizes small particles of alumina and pre-cured resin on the surface of the ornamental sheet.

 Thus, a preferred suspension composition contains a mixture of small particles of alumina and material in the form of particles of a pre-cured resin and a smaller number of particles of microcrystalline cellulose, all dispersed in water. The amount of pre-cured resin particulate material and preferably small mineral particles should be sufficient to provide the final product with the desired abrasion resistance, as discussed above, and the amount of starting binder material should be sufficient to hold the mineral particles and particulate materials pre-cured resin on the surface of the sheet from the side of the ornament. It was found that, as a rule, satisfactory results are achieved when using about 2 to 10 parts by weight. microcrystalline cellulose approximately 20-120 wt.h. alumina and pre-cured resin particulate material, however, it is possible to work outside this range. The number of particles of the pre-cured resin should be about 1 to 6 parts by weight on one part by weight mineral particles, although it is clear that it is not only possible to work outside this range, but also that a suitable product with a thick transparent protective surface layer can be made without any mineral particles at all.

 The amount of water in the suspension is also dictated by practical considerations, because if there is too little water, the suspension becomes so thick that it is difficult to apply, on the contrary, if there is too much water, the suspension becomes so liquid that it is difficult to maintain a stable thickness due to spreading during the coating operation suspensions. So, a suspension based on water containing about 2.0 wt. microcrystalline cellulose and about 24 wt. alumina and materials in the form of particles of pre-cured resin is stable, that is, alumina and particles of pre-cured resin are not deposited, however, if more than about 3.5 wt. microcrystalline cellulose and about 24 wt. alumina and particles in the form of particles of pre-cured resin, the suspension becomes very viscous and difficult to apply.

 A composition of particles containing minerals should also desirably contain a small amount of a wetting agent, preferably a nonionic wetting agent, as well as a silane. The amount of wetting agent is not critical, but only a very small amount is desirable, and an excess does not give any advantages. In accordance with normal practice, a humidifier, a lubricant that facilitates removal of the molds, a catalyst and / or antifoam may also be present.

 If silane is used, it acts as a binder that chemically binds alumina or other inorganic particles with particles of pre-cured melamine resin and / or with a matrix of melamine resin after impregnation and curing, this provides better initial wear, since alumina particles chemically bind to melamine resin, in addition to the fact that they are connected with it mechanically and, therefore, remain more in place during abrasive wear. The silane should be selected from among silanes that are compatible with the particular thermosetting resin used as a binder for laminates, in this regard, silanes having amino groups such as gamma-amino-propyltrimethoxysilane are particularly effective for use with melamine resins. It does not require a large amount of the silane used, and in fact, only 0.5 wt.% Is sufficient to increase the abrasion resistance of the final laminate. mineral in the form of particles, it is proposed to use a maximum amount of about 2 wt. alumina or other solid particles, since large quantities will not lead to any significantly better results, but simply increase the cost of raw materials.

After coating with the aforementioned coating composition, the decorative paper is dried and then impregnated in the usual way with a suitable thermosetting resin, for example, melamine resin or polyester. Before the ornamental sheet is impregnated with melamine resin, a coating that uses microcrystalline cellulose as a binder must be dried at elevated temperature. So, the minimum temperature during drying is about 140 ^o F (60 ^o C), and the preferred temperature during drying is in the range from 240-270 ^o F (115.6-132 ^o C). After drying, the impregnated and coated ornamental paper is folded with a plurality of inner sheets impregnated with resin, or other substrate material, and layered material is formed in the usual manner by heating and under pressure.

 Another method for achieving the objectives of the present invention is a one-step method of applying a layer of material in the form of particles of pre-cured resin to the surface of an ornamental sheet, while completely saturating the ornamental sheet with resin in a one-step operation, in which the uncured liquid resin is a carrier of particles of pre-cured resin and particles of minerals, abrasion resistant. This method by which the present invention is achieved is best described as follows.

 (1) Preparation of a mixture of a liquid thermosetting impregnating resin and a coating composition, wherein the coating composition comprises particles in the form of particles of a pre-cured synthetic resin in a concentration sufficient to allow the resin to deposit a pre-selected thickness on the surface of the laminate, and a binder starting material for particles of pre-cured resin, for example, microcrystalline cellulose or even sticky particles of partially cured melamine resin, moreover, the starting binder material is compatible with the thermosetting impregnating resin and can withstand the following conditions when forming a layered material, while the starting binder material is in the form of particles of a pre-cured resin with the surface of the unsaturated paper sheet, the starting binder material also serves to suspend the material in the form of particles pre-cured resin in a liquid thermosetting impregnating resin.

 (2) Applying a protective surface layer and impregnation in one operation by coating a mixture of a liquid thermosetting impregnating resin and a coating composition, preferably having a viscosity of approximately not more than 200-250 cP, on the outer surface of the unsaturated paper sheet at such a rate that the unsaturated paper sheet becomes essentially saturated liquid thermosetting impregnating resin and the coating composition has become deposited on the outer surface.

 (3) Drying the coated and impregnated ornamental paper sheet in order to obtain a decorative sheet ready to produce a laminate.

 As noted above, in stage (1), it is not necessary to add a solid mineral with a small particle size in a concentration sufficient to increase abrasion resistance without reducing visibility to the materials in the form of particles of pre-cured resin, in which case it is possible to reduce the coating thickness without loss of abrasion resistance.

 The solid mineral that can be used in the composition for the material in the form of particles of a cured polymer has a small particle size, as described above, preferably an average particle size of between about 0.5 and 9 μm, although, as indicated above, large sizes can be used in quantities sufficient to provide an abrasion resistant layer without reducing visibility. It will be clear that the viscosity of the liquid must be sufficient to maintain the mineral particles in suspension together with the particles of the pre-cured resin.

 The coating / impregnation step in one operation can be carried out in one or several stages, that is, it is possible to carry out a complete impregnation at the same stage where the coating is applied, or (in the alternative case) partial impregnation can be carried out in a continuous process according to the first stage with the coating followed by a second impregnation in the stream of resin solution from the bottom.

 As noted above, pre-cured resin particulate materials are selected from the group consisting of melamine, polyester, epoxy, cured acrylic and the like, or mixtures thereof. The binder material is preferably Avicel, sold as a mixture of approximately 89% microcrystalline cellulose and 11% carboxymethyl cellulose (CMC). It is also possible, although not preferable, that the starting binder material is a resin used as a binder for laminate, in this case, the resin used as a binder for laminate should be a relatively viscous type of syrup and the like.

 A suitable preferred composition contains 1 parts by weight "Avicel" for 4-60 wt. including a combination of mineral particles and materials in the form of particles of pre-cured resin. As indicated above, a suitable range is about (1-6): 1, although the ratio of materials in the form of particles of pre-cured resin to mineral particles is subject to wide variation. It is also possible to add small additional amounts of CMC (or not to add at all) and a small amount of silane. It is preferable to introduce a small amount of surfactant and a small amount of solid lubricant to provide abrasion resistance.

 There are six important variables in the composition, three of which are independent, and three are dependent. The weight of ornamented paper, the content of liquid resin, and the weight of the abrasion resistant composition are independent of composition. The requirements for these variables are determined by external factors such as color, degree of final saturation, and abrasion resistance. The weight of the (dry) impregnating resin per unit surface area depends on the combination of the main weight of the paper and the resin content. Viscosity depends on the total volume of liquid in comparison with the content of the material in the form of particles. Therefore, the amount of water added to the liquid resin depends on the viscosity achieved by mixing the abrasion-resistant composition and undiluted resin and the additional volume required to reduce the viscosity to the desired level to facilitate simultaneous coating and impregnation to less than about 250 cP (preferably about 100 cP).

 As indicated above, the third method is the transfer method. In this method, the coating of the present invention is applied to a transfer substrate and dried thereon. The transfer substrate is then laid down face down on a fully or partially saturated sheet with an ornament in the usual operation of pressing the laminate or on another suitable surface, for example, a layer of wood veneer. After the operation of forming the layered material is completed under conditions of sufficient magnitude, sufficient heat, time and sufficient pressure, the laminated material is peeled off from the transfer substrate or, conversely, the protective coating of the present invention is transferred to the upper surface of the ornamented sheet or substrate.

 A fourth method by which the present invention can be carried out is a method of applying varnish. Here, the composition is directly applied to a substrate, such as wood veneer, and then dried and finally pressed by heating and pressure.

 In preferred embodiments of the invention, a fully cured melamine resin is used, finely ground to a powder, which during pressing acts as a physical spacer between the pressing plate and the decorative layer. As a result of the selection of a particle that is a particle of the same resin as the impregnating resin, the refractive index of the protective surface layer in the final laminate will be the same, which leads after pressing to a non-turbid highly transparent surface of the laminate. The transparency achieved in this way is clean enough to use a single-color sheet without losing brightness or hue.

 In addition to a coating with a clean, thick surface, many other decorative coatings can be obtained by changing the material in the form of particles of pre-cured resin and the size of its particles. Such decorative coatings include various textures. Interesting visual effects can be obtained by using materials in the form of colored pre-cured particles. It is expected that changes in appearance are numerous and depend on particle size, pre-cured resin particulate materials, amounts, layer thickness and pigmentation. The actual achievement of the desired appearance can be determined on the basis of ordinary experiments from the point of view of the present description.

 Example 1

Суспензия ингредиентов, включающая 60 частей вышеуказанных частиц предварительно отвержденной меламиновой смолы и 60 частей Al₂O₃ со средним размером частиц 1 мкм, была получена в смесителе Уоринга, как указано ниже. К перемешиваемой воде добавили семь с половиной частей микрокристаллической целлюлозы (Avicel RC 581) и 2,5 части КМЦ. После пребывания в смесителе в течение 2-3 мин Avicel был полностью диспергирован, затем примешивали оксид алюминия и частицы предварительно отвержденной смолы.Melamine resin particulate materials were prepared by heating the melamine resin at 300 ^° F until curing. Once cured, the material is milled to the following approximate particle size distribution:

A suspension of ingredients, including 60 parts of the above particles of pre-cured melamine resin and 60 parts of Al ₂ O ₃ with an average particle size of 1 μm, was obtained in a Waring mixer, as described below. To the stirred water, seven and a half parts of microcrystalline cellulose (Avicel RC 581) and 2.5 parts of CMC were added. After staying in the mixer for 2-3 minutes, Avicel was completely dispersed, then alumina and particles of pre-cured resin were mixed.

The final suspension was applied up to 50 lb / rm (0.705 g / m ² ) and 65 lb / rm (0.917 g / m ² ) on unimpregnated sheets, on the surface of which a wood texture pattern and a kaleidoscopic pattern were printed, respectively. The coating was dried for 3 minutes at approximately 265 ^° F (129.4 ^° C). After that, the paper was normally saturated using melamine formaldehyde resin and dried in accordance with conventional methods. The resin content was 51-55.6% and the volatiles content was 4.6-5.2%. The layered material was made and pressed using a general general cycle, i.e., at about 290 ^° F (143.3 ^° C) 1000 psi ( 6894.76 kPa) for about 25 minutes.

 Example 2

 1575 lb (714.41 kg) liquid melamine resin was prepared for ornamental-impregnated paper in accordance with standard practice. The surfactant TRITON CF 21 was added in an amount of 0.001 wt. including 192.8 pounds of liquid resin. Stirring was carried out at high speed in a mixer with a low shear force for 5 minutes 11 pounds of Avicel were quickly added in such a way as to avoid clumping or the formation of separate pieces. Immediately thereafter, 47 pounds (27.32 kg) of pre-cured melamine resin particles and 47 pounds (27.32 kg) 30 μm alumina were quickly added.

 The viscosity was measured after adding 70 gal (264.98 L) of water in order to obtain a viscosity of not more than 150 cP (Brookfield viscometer # 3, the shaft rotated at 12 rpm).

65 pound / rim (0.916 g / m ² ) coated paper was coated at a rate of 196.1 pound / rm (2.765 g / m ² ). The paper was dried at an elevated temperature, and using this paper, a layered material was prepared in the usual manner.

 Abrasion results (see table 1).

 Example 3

 Carried out as well as the above example 2, using 20 and 25 μm alumina for each additional sample.

 Abrasion results (see table 2).

 Example 4. Protective surface layer of medium weight.

To apply the surface layer and simultaneously saturate the paper with the printed ornament, the following composition was prepared:
150 gallons (567.82 L) undiluted melamine resin 1,575 pounds (714.41 kg);
70 gallons (264.98 L) of water;
11 pounds Avicel (4,990 kg);
92 pounds (41.73 kg) 30 microns (average particle size) alumina;
92 pounds (41.73 kg) of pre-cured melamine resin particles, maximum particle size 100 μm;
0.27 pounds (0.122 kg) of grease for Infirnol molds;
6.2 pounds (2.812 kg) of a Nacure 3525 melamine resin curing catalyst;
32 lbs (14.515 kg) diethylene glycol based moisturizer;
1.36 lbs (0.617 kg) of Bubrake Antifoam.

Coating (impregnation) was carried out at a rate of 57.8 lb / rm (0.815 g / m ² ) of undiluted solid melamine resins, with Avicel being applied at a rate of 0.66 lb / rm (0.009 g / m ² ), alumina at a rate of 5 , 62 lb / rm (0.079 g / m ² ), particles of pre-cured melamine resin with a flow rate of 5.62 lb / rm (0.0079 g / m ² )? and a moisturizer with a flow rate of 1.64 lb / riv (0.0231 g / m ² ). After passing through the dryer, the ornamented sheet had a resin content of 52% and a volatile matter content of 6%
A sheet with an ornament was pressed into a decorative high-pressure laminate in the usual way, the resulting laminated material met all the standards of NAEP and had excellent abrasion resistance and wear resistance on a sliding drum.

 Example 5. A laboratory composition that creates a sense of depth, resistant to strong punching.

The laboratory composition for impregnation / coating was obtained and applied to an ornamental sheet at a rate of 58.31 lb / rm (0.822 g / m ² ) of undiluted solid resin, 0.67 lb / rm (0.009 g / m ² ) Avicel, 26, 1 lb / rm (0.368 g / m ² ) of pre-cured melamine resin solids having a maximum particle size of 100 μm, and 6.53 lb / rm (0.092 g / m ² ) of aluminum oxide. After the paper passed through the dryer, the resin content of the paper was 60% and the volatile content of 6%. The transparent protective surface layer had a thickness equivalent to more than 20 lb / rm (0.282 g / m ² ) of solids. After pressing the ornamental sheet together with several inner sheets impregnated with phenol-aldehyde resin, a layered material was obtained that fully complies with the NAEP standards, which, in addition, had excellent resistance to bursting and in which the ornamental sheet could be clearly visible but created the impression of a deep layered material.

Example 6. Replacement ARP ^® .

The following composition was obtained for simultaneous coating and impregnation of a sheet with one color:
195 gallons (738.15 L) of undiluted melamine resin (2.047.5 pounds) (928.73 kg);
50 gallons of water (189.27 L);
15 pounds Avicel (6.803 kg);
2.9 pounds of wax (1.315 kg);
44 pounds (19.958 kg) alumina 15 microns;
44 pounds (19.958 kg) of pre-cured melamine resin particles (maximum particle size 100 μm);
0.35 lbs (0.158 kg) of wetting agent Emerset 2652;
0.32 lbs (0.145 kg) lubricant for Infirnol molds;
8.2 lbs. (3.719 kg) of Nacure 3525 catalyst;
1.1 lbs. (0.499 kg) of Bubrake Defoamer.

The above composition was applied at a rate of 60.93 lb / rm (0.859 g / m ² ) uncured resin solid, 0.74 lb / rm (0.017 g / m ² ) Avicel, 0.13 lb / rm (0.002 m ² ) wax, 2.17 lb / rm (0.031 g / m ² ) alumina and 2.17 lb / rm (0.0031 g / m ² ) particles of pre-cured melamine resin. The single color coated and soaked sheet was then passed through a drying oven in the usual manner. When developing, it had a resin content of 52% and a volatiles content of 6%. A single color sheet was used to form the laminate in the usual manner. The final layered material had excellent abrasion resistance on a sliding drum and fully met all the standards of NAEP. Due to the relatively small amount of alumina present, tool wear is reduced when cutting this laminate.

 Example 7

The following composition was obtained for simultaneous coating and impregnation of a sheet with an ornament (laboratory quantities):
447 g of melamine resin (268.2 g of solids);
166 g of water;
3.12 g of Avicel;
0.87 antifoaming wetting agent (31 drops);
26.1 g alumina with an average particle size of 30 microns;
26.1 g of the pre-cured melamine resin particle of Example 1;
0.09 g grease for Infirnol molds (3 drops);
9.08 g diethylene glycol;
1.78 g of Nacure 3525 catalyst (88 drops);
0.31 g defoamer Bubrake (10 drops).

The above composition with a total solids content in the range of 56-58% and a total resin solids content (excluding pre-cured resin particles) in the range of about 51-53% was applied to the ornament sheet at the following rate:
Uncured melamine resin 62.69 (0.884 g / m ² ) 68.02 (0.959 g / m ² ) lb / Rome;
Avicel (3,000 ft ² ) 0.72 (0.010 g / m ² ) 0.78 (0.011 g / m ² ) lb / Rome;
Particles of pre-cured melamine resin 6.09 (0.086 g / m ² ) 6.61 (0.093 g / m ² ) lb / Rome;
Alumina particles 6.09 (0.086 g / m ² ) 6.61 (0.093 g / m ² ) lb / Rome;
Diethylene glycol 2.12 (0.031 g / m ² ) 2.30 (0.032 g / m ² ) lb / Rome.

 Example 8

Example 7 was repeated using the following composition:
Melamine resin 361.0 g (216.6 g solids);
Water 201.0 g;
Avicel 3.12 g;
Anti-foaming wetting agent 0.87 g (31 drops);
Alumina (average particle size 30 microns) 26.1 g;
Particles of the pre-cured melamine resin of Example 1 26.1 g;
Lubricant for Infirnol forms 0.09 g (3 drops);
Diethylene glycol 9.08 g;
Nacure Catalyst 1.78 g (88 drops);
Bubrake Antifoam 0.31 g (10 drops).

This composition was applied to an ornamental paper sheet at a rate of 51.01 lb / rm (0.719 g / m ² ) for uncured melamine resin, plus 4.22 lb / rm (0.06 g / m ² ) of other components, which provided total consumption when applied 55.23 lb / rm (0.779 g / m ² ).

Additional examples
An example similar to Example 5 above was prepared, but no alumina was used at all. Received a product that meets the standards of NAEP, which has excellent transparency and resistance to punching. The application rate of the pre-cured particles is 35 lb / rm (0.494 g / m ² ).

 Another example was carried out similarly to example 6, but Avicel was replaced by sodium alginate. The results are satisfactory.

 Another example was carried out using a composition similar to the composition of Example 1, the composition being applied directly to the upper surface of a wooden plywood panel. After coating and drying, the panel was pressed under the influence of heat and pressure to obtain a protective coating on the wood panel.

Another test for the production of low-pressure paperboard using polyester resin was conducted. As the substrate used cardboard Masonite ^® . A wood texture ornament sheet was used, and the coating / impregnation composition was similar to that of Example 5, but the pre-cured resin particles were polyester particles and the impregnated resin was the same uncured polyester resin. The final product had excellent abrasion resistance.

 The preceding description of specific embodiments of the invention reveals the general nature of the invention, so that other persons, using well-known knowledge, can easily modify and / or adapt these specific options for various applications without deviating from general concepts, therefore, such adaptations and modifications should be interpreted as being within the described options and within the concept of the invention.

Claims (47)

 1. An ornamental sheet for use in the manufacture of a decorative laminate, comprising a sheet of paper impregnated with a thermosetting resin and a protective layer placed on top of the paper sheet, characterized in that the protective layer is substantially transparent and contains particles of a previously cured thermosetting resin, the refractive index of the particles being preliminarily the cured resin is substantially the same as the refractive index of the impregnating thermosetting resin.  2. The sheet according to claim 1, characterized in that the protective layer contains particles of mineral material of small sizes having a Mohs hardness of at least 7 in the matrix of the thermosetting resin.  3. The sheet according to claim 1 or 2, characterized in that the protective layer contains the original binder material.  4. A sheet according to any one of claims 1 to 3, characterized in that the particles of the pre-cured resin and the impregnating thermosetting resin represent the same resin.  5. The sheet according to claim 4, characterized in that the resin is a polyester resin, melamine resin or urea resin.  6. The sheet according to any one of paragraphs.2 to 5, characterized in that the mineral particles of the protective layer have an average particle size of not more than 50 microns.  7. The sheet according to any one of paragraphs.3 to 6, characterized in that the starting binder material of the protective layer contains microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.  8. The sheet according to any one of paragraphs.1 to 7, characterized in that the transparent protective layer has a thickness of 2 to 3 mm, preferably 3 mm  9. A decorative laminate comprising a substrate with a decorative top layer formed from a cured and bonded ornamental paper impregnated with a thermosetting resin, and a protective layer placed on top of the decorative layer, characterized in that the protective layer is abrasion resistant essentially transparent and contains particles of a pre-cured thermosetting resin, the refractive index of the particles of the pre-cured resin is essentially the same as the refractive index the impregnation of thermosetting resin.  10. The material according to claim 9, characterized in that the protective layer contains particles of mineral material of small sizes having a Mohs hardness of at least 7 in the matrix of the thermosetting resin.  11. The material according to claim 9 or 10, characterized in that the protective layer contains the original binder material.  12. The material according to any one of paragraphs.9 to 11, characterized in that the particles of the pre-cured resin and the thermosetting resin represent the same resin.  13. The material according to p. 12, characterized in that the resin is a polyester resin, melamine resin or urea resin.  14. The material according to any one of paragraphs.10 to 13, characterized in that the mineral particles of the protective layer have an average particle size of not more than 50 microns.  15. The material according to any one of claims 11 to 14, characterized in that the starting binder material of the protective layer contains microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.  16. The material according to any one of paragraphs.9 to 15, characterized in that the protective layer has a thickness of 2 to 3 mm, preferably 3 mm  17. The material according to any one of paragraphs.9 to 16, characterized in that the substrate is formed of wood.  18. The material according to any one of paragraphs.9 to 17, characterized in that the substrate is formed of wood veneer.  19. The material according to claim 9, characterized in that it is a low pressure laminate, the resin being a polyester resin or a melamine resin.  20. The material according to claim 9, characterized in that it is a high pressure laminate, the resin being a melamine resin or a urea resin, the substrate is made of core sheets impregnated with a resin, which is preferably a phenol-aldehyde resin.  21. The material according to claim 11, characterized in that the protective layer contains 5 to 30 wt. including particles of a mineral selected from the group consisting of alumina, silica and mixtures thereof; 1 5 parts by weight a starting binder material selected from the group consisting of microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, and mixtures thereof; particles of pre-cured resin, taken in an amount from equal to the number of particles of the mineral to an amount six times the number of particles of the mineral; a thermosetting resin with a refractive index substantially equal to the refractive index of the pre-cured resin particles, taken in an amount sufficient to form a constant matrix for the mineral particles and for the pre-cured resin particles.  22. The material according to claim 9, characterized in that essentially all of the particles of the pre-cured resin have sizes less than 250 microns.  23. The material according to item 22, wherein the protective layer contains 100 parts by weight particles of pre-cured resin up to 100 wt.h. particles of finely dispersed, colorless, abrasion-resistant mineral material with a Mohs hardness of at least 7 and an average particle size of at least 50 μm, and the starting binder material in an amount sufficient to hold the particles of the mineral material and particles of the pre-cured resin on the sheet surface paper with ornament. 24. Material according to any one of claims 9, 21 to 23, characterized in that the protective layer contains 0.212 0.282 g / m ² particles of pre-cured melamine resin. 25. The material according to any one of paragraphs.9, 21 to 23, characterized in that the transparent protective layer has a thickness corresponding to 0.085 0.113 g / m ² particles of pre-cured resin and particles of mineral material.  26. A method of manufacturing a sheet with an ornament used in the production of decorative laminated material, which consists in applying a protective layer to the sheet with the ornament and impregnating the sheet with the thermosetting resin ornament, characterized in that a protective layer containing particles of the previously cured thermosetting resin is used, the refractive index particles of pre-cured resin is essentially the same as the refractive index of the matrix of the impregnating thermosetting resin.  27. The method according to p. 26, characterized in that they use a protective layer containing mineral particles of small sizes, having a Mohs hardness of at least 7 in the matrix of the thermosetting resin.  28. The method according to p. 26 or 27, characterized in that they use a protective layer containing the starting binder material.  29. The method according to any one of paragraphs.26 to 28, characterized in that the same resin is used as particles of the pre-cured resin and the thermosetting resin.  30. The method according to clause 29, wherein using a resin, which is a polyester resin, melamine resin or urea resin.  31. The method according to any one of paragraphs.27 to 30, characterized in that the use of mineral particles of the protective layer with an average particle size of not more than 50 microns.  32. The method according to any of paragraphs 28 to 31, characterized in that they use the starting binder material of the protective layer containing microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.  33. The method according to any one of paragraphs.26 to 32, characterized in that the transparent protective layer has a thickness of 2 to 3 mm, preferably 3 mm  34. The method according to any of paragraphs 28 to 33, characterized in that the application of the protective layer on the sheet with the ornament and the impregnation of the sheet with the thermosetting resin ornament is carried out in two separate stages, the protective layer being first applied to the sheet with the ornament by applying a wet layer of particles previously the cured thermosetting resin and the starting binder material, the wet layer is dried, and then the sheet with the thermosetting resin is impregnated.  35. The method according to clause 34, wherein when applied to a sheet with an ornament of the protective layer, use a wet layer containing mineral particles.  36. The method according to any one of claims 27 to 33, characterized in that the application of a protective layer to the sheet with the ornament and the impregnation of the sheet with the thermosetting resin is carried out in one step, and a mixture of a thermosetting resin and particles of a previously cured thermosetting resin having a viscosity is first prepared no more than 250 SPz, apply this mixture to a sheet with an ornament, with a layer of particles of pre-cured resin applied to the sheet with the ornament, and simultaneously impregnating the sheet with the ornament with a thermosetting resin, and then lyayut drying the coated and impregnated with the decor sheet.  37. The method according to p. 36, characterized in that the mixture comprises mineral particles of small sizes and the starting binder material.  38. A method of manufacturing a decorative laminate, which consists in assembling a substrate and a decorative top layer impregnated with a thermosetting resin with a protective layer placed on top of it, applying heat and pressure to the assembly with the possibility of spreading and at least partially curing the thermosetting resin, characterized in that use a protective layer containing a cured thermosetting resin formed from particles of pre-cured resin, and l the refraction of the particles of the pre-cured resin is essentially the same as the refractive index of the impregnating thermoset resin in at least partially cured form, and the protective layer is transparent and resistant to abrasion.  39. The method according to § 38, wherein the cured thermosetting resin includes mineral particles of small sizes, having a Mohs hardness of at least 7, in the matrix of the thermosetting resin, the thermosetting resin being compatible with the thermosetting resin, which is impregnated with a decorative top layer.  40. The method according to § 38 or 39, characterized in that the cured thermosetting resin includes a starting binder material.  41. The method according to any of claims 38 to 40, characterized in that the same resin is used as the particles of the pre-cured resin and the thermosetting resin.  42. The method according to paragraph 41, wherein the resin is used, which is a polyester resin, melamine resin or urea resin.  43. The method according to any one of paragraphs 38 to 42, characterized in that the use of mineral particles of the protective layer with an average particle size of not more than 50 microns.  44. The method according to any of paragraphs.40 to 43, characterized in that they use the starting binder material of the protective layer containing microcrystalline cellulose, carboxymethyl cellulose, sodium alginate, or mixtures thereof.  45. The method according to any one of paragraphs 38 to 44, characterized in that the transparent protective layer has a thickness of 2 to 3 mm, preferably 3 mm  46. The method according to § 38, wherein the resulting laminate is a low pressure material, using a polyester resin or melamine resin.  47. The method according to § 38, wherein the resulting laminate is a high pressure material, using a melamine resin or a urea resin, and the substrate is made of core sheets impregnated with a resin, which is preferably phenol-aldehyde resin.

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