DE2509338A1 - PLATES WITH DECORATIVE SURFACE AND METHOD FOR THEIR PRODUCTION - Google Patents

Description

Dr. D. Thomson PATE NTA N WALTS OFFICE

W. Weinkauif _{Tchton {0} r ₉ ) kkh Dr. I. Ruch ^ ⁰²¹²

ι Telex 5-24303 topat λγλλοΟΟ

Dr. H. Agular 2 b 0 9 ο d ö PATENT LAWYERS Munich: Frankfurt / M .:

Dr. rer. nat. D. Thomeen Dlpl.-Ing. W. Welnkauff

Dr. rer. nat I. Rudi (Fuchehohl 71) Dipl.- Ing.Dr. H. Agular

8000 Munich 2 Kaisor-Ludwig-Platz 6 March 4th 1975

Formica International Limited
London, England

Panels with a decorative surface and process for their manufacture

The invention relates to panels with a decorative surface, the decorative surface by a a decorative fiber sheet impregnated with a thermosetting resin is formed.

The use of resin-impregnated decorative fiber webs in the production of panels provided with a decorative surface is known. Such tracks can be on different Way to be used with the resin either

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in the thermosetting state or in the thermosetting state at the time of bringing it together with the plate. For example, particle board provided with a decorative surface is known to be manufactured using a one-step, two-step or three-step process. In the one-step process, one with a thermosetting resin impregnated decorative sheet, optionally in combination with other resin-impregnated fiber sheets, on a or applied to each face of a layer of wood chips or chips; the arrangement is then closed by heat and pressure solidified into a unitary structure, wherein the thermosetting resin in the assembly during the solidification to the thermoset State is cured. The two-step process is a mode of operation, one with a thermoset Resin impregnated decorative sheet alone or optionally in conjunction with other resin impregnated sheets on one or each Surface of the previously prepared panel is applied; the assembly is then again subjected to heat and pressure in order to to solidify them into a hardened unitary structure. The three step process is one with a thermosetting Resin impregnated decorative sheet under heat and pressure (usually as part of a batch of others with a thermosetting Resin-impregnated fiber webs to form a laminate) cured; the cured sheet or laminate becomes then bonded to one or both surfaces of a previously formed panel using a suitable adhesive.

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In a similar way, it is known to change backing plates, for example plywood, hardboard, plasterboard and asbestos panels, with a decorative surface or with decorative To provide surfaces with decorative fiber webs impregnated with a thermosetting or thermosetting resin; these panels are usually manufactured using a two-step or three-step process.

When the production of a panel with a decorative surface with high abrasion resistance or wear resistance It is known to have a wear layer, usually using a translucent one, with a thermosetting resin impregnated alpha cellulose paper web, (referred to as the top layer or topsheet) over the decorative Form fiber web.

In these known panels, the top layer fulfills various important functions. At first it acts as a reinforcement for the resinous wear layer, the paper serving to firmly bind the resin, so that hairline cracking or Avoid tearing. Second, it acts as a resin carrier, thereby forming the resinous wear surface layer on the decorative web is facilitated. Thirdly, the uppermost layer in the flow restriction and so serves to limit the extent to which the resin forms the wear surface layer forms, penetrates the decorative webs during the working process; so one also achieves that the resinous wear layer is held where it

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is required.

However, the use of such a top layer or topsheet has certain disadvantages. First is the Upper layer membrane expensive; the cost of machining, machining, energy and materials used occur in the treatment of the top layer with thermosetting resin in order to form this into a wear surface layer, represent a significant part of the total cost of the decoration area. Second, the topsheet paper is not complete transparent, with the result that it partially obscures the decorative sheet.

However, clarity of the wear surface layer is desirable when the decorative effect is through a printed or patterned decorative sheet is created, as any lack of clarity affects the decorative effect. Even at simply colored decorative panels, clarity of the wearing surface layer is desirable - although of less importance, as this ensures that the coloring of the decorative sheet appears without a reduction in gloss and brightness occurs. It is also the object of the invention to create such plates.

Thus, according to the invention, panels are created with a decorative surface, the panels with a high degree of clarity of the wearing surface layer without adversely affecting the

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have other properties of the decorative surface. According to the invention, a method for producing such plates with good abrasion resistance or wear resistance is also provided with a smaller amount of thermosetting or thermosetting resin together in the decorative and wear surface layers as on the other hand commonly used created when one such flat plates with a topmost Layer or upper class produces.

The panels according to the invention consist of a supporting base, a decorative sheet and a wear surface layer, wherein the supporting base is made of lignocellulosic material, a metal sheet or a board made of an inorganic material Material and the decorative sheet made of a decorative fiber sheet, which is finished with a first or permanent, thermosetting or thermoset resin is impregnated, and also the wear surface layer of a coating on the relevant The surface of the decorative sheet, which is turned away from the supporting base, consists of a second refined or permanent thermosetting resin and finely divided barium sulfate.

These panels made of coated decorative fiber webs, show satisfactory abrasion properties or wear properties with low coating weights; aside from that has surprisingly been found that, despite the absence of fibrous cellulosic material in the outer

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Wear layer this layer does not form hairline cracks or shows no cracking to any substantial extent.

The fiber webs can be made from any suitable, simply colored or printed decorative fiber webs consist, for example, of a paper web, a woven cotton web or such a web that is completely or partly made of synthetic fiber materials. The use of a paper web, in particular a decorative, simply dyed or printed alpha cellulose paper web with a basis weight of 6o to 2oo g / m.

The coated resin impregnated decorative fiber sheet is conveniently made by first a decorative fiber fabric impregnated with a first refined or permanent thermosetting resin composition and then the Decorative surface coated with a mixture that a second refined or permanent thermosetting resin and finely divided barium sulfate contains. The impregnated and coated Tissue is then dried before being cut into sheets of the desired size. Optionally, it can Impregnated fiber fabrics are also dried before the coating is applied.

The term "refined or permanent thermosetting Resin "is commonly used in this technical field to refer to those thermosetting resins that are not

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subject to noticeable color deterioration during the curing process under heat and pressure. The term "refined or permanent thermoset resin "refers to those thermoset resins that are refined by curing the or durable thermosetting resins.

Suitable resins are, for example, melamine / formaldehyde, urea / formaldehyde, melamine / urea / formaldehyde and cross-linked polyester resins.

The first and the second refined permanent thermosetting Resin can be the same or different. The second thermosetting resin is preferably one used in the thermosetting one State has an index of refraction that approaches that of barium sulfate.

The refractive index of barium sulfate is 1.62 to 1.64, while that of cured melamine / formaldehyde resins 1.6 is 3 to 1.67; this similarity in the refractive indices of the two materials combined with the fact that Both are colorless in the preferred application form, ensures that an applied coating that this resin contains, is highly translucent. The use of coating mixtures, the melamine / formaldehyde resins, is preferred contain.

The barium sulphate used can be of any suitable quality, e.g. acid-washed, naturally pre-

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coming mineral, barite or precipitated blanc fixe. However, regardless of its source, the barium sulfate should be colorless and translucent as far as possible.

The particle size of the barium sulfate can vary within a wide range; however preferably have 95% by weight of the material has a particle size of less than 10 microns; It is also preferred that 65% by weight of the material have a particle size of 1.5 to 10 microns.

The amount of barium sulfate that is used in the coating mixture can also be used over a wide range be varied; for example, amounts of 80 to 14 parts by weight, preferably 110 to 14o parts by weight of barium sulfate 100 parts by weight of resin solids are used.

The coating mixture is suitably prepared by mixing with stirring in an aqueous or alcoholic Solution of the thermosetting resin (e.g. amino-triazine-formaldehyde resin, especially melamine / formaldehyde resin) either with a Suspension of barium sulfate in water or the dry, finely divided material. The resin can either suitable refined or permanent thermosetting resin which, when cured, is essentially colorless and is transparent. Optionally, a curing catalyst (preferably a latent catalyst) can be used in the coating mixture will.

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The panels according to the invention can be provided with an abrasion-resistant decorative surface, if small Quantities of a suitable finely divided wear-resistant material with a hardness on the Moh * see scale of at least 6 Included in the coating mixture are «The use of finely divided silicon dioxide (especially quartz) or finely divided Alpha alumina is preferred. The used Amounts of any such material should suitably be kept as low as possible commensurate with the desired level of abrasion resistance, since such materials, if Have refractive indices different from that of the second refined or permanent thermoset or thermoset Resin, cause a certain loss of clarity of the applied layer. However, have the same Content and with the same thickness of abrasion-resistant material upper layers or wear layers, which from the above coating mixtures described are produced, greater clarity than those layers which contain cellulosic materials.

If abrasion-resistant materials are to be used, is the use of colorless abrasion-resistant materials in amounts of up to 20 parts by weight per 100 parts of resin solids preferred in the coating mix; they can be incorporated into the coating mixture in any suitable manner so that a uniform dispersion is formed.

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The particle size of the finely divided wear-resistant materials used is suitably no greater than 50 microns; preferably the particle size is in the range of 1 to 30 microns and the mean particle size is 12 to 25 microns.

The coating mixture can also contain an additive to regulate the penetration, and thus the viscosity of the mixture can be changed and the extent to which the mixture penetrates the impregnated decorative sheet can be limited. The addition of such an agent has been found to improve the wear resistance or abrasion resistance of the Decoration area with reference to a given coating weight. It is believed that this results from the fact that the additive is thicker in limiting the penetration of the mixture Resin layer on the surface. Examples of suitable additives are cellulose derivatives, e.g. carboxymethyl cellulose, and preferably the alginates, in particular sodium alginate, in an amount of 0.1 to 2.0% by weight, preferably 0.2 to 0.75 % By weight, based in each case on the total weight of the coating mixture.

The coating mixture can be applied at any suitable coating weight; is suitably however the coating weight after drying 1o to 5o,

2 preferably 2o to 4o and in particular 25 to 35 g / m.

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After the coating, the decorative sheet is dried to reduce the volatile material content in the treated Web is reduced to such a degree that is suitable for the subsequent consolidation step. The content of volatile materials is preferably 6 to 8.5% by weight, in particular reduced by about 7% by weight.

The processes of impregnation, drying and coating can be carried out using suitable known techniques. For example, the impregnation can be carried out after a Dipping process can be carried out using a resin varnish, further drying by passing through a Hot air chamber and coating using a knife - or Roll coating device.

It is preferred to impregnate the decorative sheet in fabric form with a resin varnish, which refines or is resistant contains thermosetting resin dissolved or dispersed in a volatile solvent. Suitable resin varnishes are those that for use in the manufacture of resin impregnated decorative fiber webs are known. Optionally, a curing catalyst (preferably a latent catalyst) can be used in the Impregnation mixture can be used. The decorative sheet is impregnated in a suitable manner so that in the dried impregnated web a resin content of 3o to 6o% by weight, preferably 35 to 45% by weight is created.

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The treated decorative fiber web can after drying and hardened by heating under pressure in a solidified suitable press and then adhesively connected to a preformed base, so that a decorative surface plate is formed; however, it is preferred that the hardening and solidification are carried out simultaneously with the binding of the decorative sheet to the substrate.

In this preferred mode of operation, the decorative sheet is placed on a surface of the selected substrate; the arrangement is then subjected to heat and pressure, as a result of which the thermosetting resin mixtures are cured and the decorative sheet is bonded to the substrate.

If desired, an adhesive layer can be arranged between the decorative sheet and the base prior to solidification will. Suitable adhesive layers are known and are, for example, curable resin mixtures in the form of films or coatings or in the form of impregnation of fiber webs »

In the preferred embodiment, where hardening, solidifying and binding take place in a single process, the decorative surface of the plates can be provided with a texture, a design or a pattern in relief or in a recess, namely in cooperation with the decorative surface using a pressure plate or of a tool with a suitably contoured work surface.

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It can be seen, if desired, according to the invention, panels with decorative surfaces on both larger sides be formed by arranging decorative webs on both larger sides of the base in a suitable manner.

The supporting base consists of a suitable thickness of a lignocellulosic material, a metal sheet or a board made of an inorganic material. Known suitable materials are, for example, wood panels, chipboard, pressed boards, Hardboard, plywood, steel panels, plasterboard, cement panels and asbestos panels. Preferred for use as a base are panels based on lignocellulose materials and especially chipboard.

The invention is illustrated in more detail below with reference to the examples, all parts and proportions refer to weight.

example 1

500 parts of a spray-dried melamine / formaldehyde resin with a melamine / formaldehyde ratio of about 1: 1.75 were stirred in 500 parts of water at 3o ° bis 4o C dissolved; 900 parts of a 70% strength aqueous dispersion of Blanc fixe brilliant and were added to the stirred solution 1 part of a certain latent amine salt catalyst given.

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A high quality, printed in wood grain Decorative paper was coated with a standard melamine / formaldehyde resin varnish, containing a latent catalyst, impregnated; the impregnated paper was (without intermediate drying) coated with the coating mixture prepared as above using a reverse roller on the printed surface; the treated tissue was then up to a content of 7, ο% dried on volatile substances. The impregnation was carried out so that a resin content of 40% (based on the weight of the dried impregnated fabric); Furthermore, the coating was carried out in such a way that a dry coating

weight of 30 g / m 2 was formed on the dried coated fabric.

There were then two webs of the desired size cut the fabric; one of the lanes was then placed one on top of the other on each major surface of a high quality, arranged in the surface uniform chipboard; the arrangement was made using a hydraulic press Heated plates at 15o ° C and a pressure of 15 kg / cm solidified to a uniformly hardened shape.

The decoratively designed chipboard produced in this way had a clear wood grain appearance; in comparison with similar plates made using the same printed web but made a) with a conventional top layer web and b) using a coating mixture containing 20 parts by weight of finely divided

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Silicon dioxide per 100 parts by weight of the melamine / formaldehyde resin, it has been observed that the clarity of the wearing surface layer is greater with the plates of the invention than that of the respective layers of the comparative panels.

Example 2

A simple colored decorative surface board was made by impregnating a high quality, simple dyed decorative alpha cellulose paper fabric made with a common melamine / formaldehyde resin varnish; the mesh was dried, an impregnated fabric with a resin content of 40% and a volatile content Substances of about 10% resulted.

The dried impregnated fabric was then coated on a slot coating machine, namely using a coating mixture as described in Example 1, so that, after a further drying process, such a treated fabric resulted which had a coating weight of 30 g / m 2 and a volatile matter content of 7.5%. A web was cut from this fabric and placed on a Hardboard applied; the assembly was then pressed as in Example 1 to form a decorative panel. Again, the plate so produced had an appearance with better clarity than a plate with a conventional topsheet paper, namely due to the high degree of clarity in the

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Wear surface layer.

Example 3

A single-colored decorative surface plate was produced as in Example 2, with the exception, however, that the coating mixture additionally 45 parts of finely divided fused alpha-aluminum oxide, of which essentially all had a particle size of 1 to 30 microns.

When comparing with an abrasion-resistant decorative surface panel, produced by coating the impregnated web with a mixture that contains 2o parts of cellulose fibers and 10 parts of finely divided fused aluminum oxide per 100 parts of a melamine / formaldehyde resin was observed that the wearing surface layer of the plates according to the invention had greater clarity than the comparison plates.

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Claims (1)

2503338 Claims 1./Plate with decoration surface as a further training according to patent application P 23 62 645.1, characterized by a supporting base, a decorative sheet and a Wear surface layer, with the supporting base made of lignocellulosic material, a metal sheet or a board made of an inorganic material, the decorative sheet made of a decorative fiber web impregnated with a first refined or permanent thermosetting or thermosetting resin, and the wear surface layer consisting of a coating on the surface of the decorative sheet, which is of the supporting Base is turned away, containing a second refined or permanent thermosetting or thermosetting resin and finely divided barium sulfate. 2. Plate according to claim 1, characterized in that the first and the second refined or permanent thermosetting or thermoset resin is made of the same resin. 3. Plate according to one of the preceding claims, characterized in that at least one of the refined or permanent thermosetting or thermosetting resins consists of a corresponding melamine / formaldehyde resin. 4. Plate according to one of the preceding claims, characterized in that the coating 8o to 15o, 509837/0835 preferably 11o to 14o parts by weight of barium sulfate each
Contains 100 parts by weight of resin solids in the coating. 5. Plate according to one of the preceding claims, characterized in that 95% by weight of the barium sulfate have a particle size of less than 10 microns. 6. Plate according to claim 5, characterized in that 65% by weight of the barium sulfate has a particle size of 1.5 to 10 microns. 7. Plate according to one of the preceding claims, characterized in that the coating weight on the Decorative web is 1o to 5o, preferably 25 to 35 g / m 2. 8. Plate according to one of the preceding claims, characterized in that the coating further comprises up to 2o parts by weight of a finely divided colorless wear-resistant material with a hardness according to the Moh ¹ see scale of at least 6 and a particle size in the range from 1 to microns. .9. Plate according to one of the preceding claims, characterized in that the decorative Paserbahn consists of a Alphacellulose paper web is made. 509837/0835 10. Plate according to one of the preceding claims, characterized in that the decorative web is a printed one Contains pattern or image. 11. Plate according to one of the preceding claims, characterized in that the decorative web consists of a simply colored web. 12. Plate according to one of the preceding claims, characterized in that the base consists of a plate a lignocellulosic material. 13. Plate according to one of the preceding claims, characterized in that the base consists of a chipboard. 14. A method for producing a plate according to the preceding claims, characterized in that a) a decorative fiber web impregnated with a varnish containing a first refined or permanent thermosetting resin contains, on a decorative surface of the web with a joint ·? · Settlement containing a second refined or permanent thermosetting resin and finely divided barium sulfate, applied b) the impregnated and coated web is dried, then c) the web lying on top of one another on a supporting base, the applied decorative surface from the supporting Support is provided remotely, arranged and d) the arrangement is solidified by heat and pressure. 509837/0835 15. The method according to claim 14, characterized in that a) a decorative fiber web with a paint having a first refined or permanent thermosetting resin contains, impregnated and the impregnated web is dried, b) the impregnated dried web on a decorative surface with a composition containing a second refined or permanent thermosetting resin and finely divided barium sulfate, applied, c) the impregnated and applied web dried, d) the web lying on top of one another on a supporting base, the applied decorative surface facing away from the supporting base is provided, arranged and e) the arrangement is solidified by heat and pressure. 16. The method according to claim 14 or 15, characterized in that the impregnated decorative fiber web before the application has a resin content of 3o to 6o% by weight, based on the dry weight of the resin-impregnated web. 17. The method according to any one of claims 14 to 16, characterized in that the coating mixture continues an additive to regulate the penetration, to change the viscosity of the mixture and to limit the extent, up to which the mixture penetrates the decoration paper. 509837/0835