CS274468B2 - Method of decorative laminates production - Google Patents

Description

The invention relates to a process for the production of decorative laminates, in particular decorative laminates with reduced flammability and smoke evolution by pressing the sheets of cellulose paper impregnated with a solution of phenolic and melamine-formaldehyde resin at elevated temperatures.

Various methods of producing low flammability materials are known. In the manufacture of laminates using paper and polycondensed resins with reduced flammability, the essential components are antimony trioxide for the paper and for the halogen-containing antipyrene resin. The laminates are produced by conventional methods. During the pressing process, the halogen derivatives decompose, which is manifested by undesirable bubble formation or delaminating of the plates.

In the Polish patent file no. No. 115540 describes a process for producing low flame retardant decorative laminates by treating cellulosic paper modified with a synergistic mixture of antipyrenes such as antimony trioxide and copolymers such as vinyl chloride and vinylidene chloride. Phosphoric acid esters are also commonly used to increase the fire resistance of paper laminates. This procedure provides laminates belonging to slow flame spread materials. However, they burn a large amount of toxic and asphyxiating gases and are therefore unsuitable for use in confined spaces, especially in transport and shipbuilding.

Patent Document OE. No. 2404790 describes a method of using ammonium phosphate, diammonium phosphate, and phosphoric acid to produce a non-combustible paper. However, these agents act temporarily and their non-flammable effect is related to decomposition to ammonia and phosphoric acid at temperatures below 100 ° C, while phosphoric acid and water are released at higher temperatures. Since the decomposition takes place at temperatures below 100 ° C, the paper thus produced cannot be used for the production of laminates, as the drying of the impregnated boards and their pressing is carried out at temperatures above 100 ° C. In addition, the structure of this paper is incapable of resin saturation.

Ammonium polyphosphate is used for the manufacture of self-absorbing fire-resistant coatings, as known from Polish Patent Specification No. 114868. The use of polyphosphorus compounds for anhydrous polymers in single-stage production processes, for example in injection molding, etc. is also known. In general or mostly it is not possible to use the addition of phosphorus compounds to alkaline aqueous resol resins, especially when using multi-stage processes, for example in the manufacture of laminates associated with impregnation, drying or pressing. The aqueous medium causes the hydrolysis of acids and phosphate salts, which causes the resin to gel and premature solidification.

Another well known method is the use of 15 kw organophosphorus polymers. phosphorus and 27 wt. chlorine for fire retardation of polyurethane foams, polymethyl methacrylates and phenolic, epoxy and polyester resins.

However, these phosphororganic polymers are insoluble in water and thus cannot be used for aqueous resin solutions. In addition, combustion generates a large amount of smoke with a high content of organic particles and chlorine. This makes them unusable for enclosed materials.

It is an object of the present invention to provide a process for the production of low-flammability laminates with low smoke evolution which at the same time meets the conditions prescribed for low-flammability materials in confined spaces, particularly in trains and shipbuilding.

Contrary to expectations, it was found that adding a solution of the amine in aqueous ammonia and then polyphosphoric acid to the aqueous stream. The resol of the phenolic resin or the melamine-formaldehyde resin solution will stabilize the aqueous resin solution and act appropriately on the course of the paper impregnation process, the impregnant drying and the plate pressing. This provides good quality laminates that can be used in shipbuilding.

The aim of the solution was achieved and the disadvantages of the known known production methods were eliminated in the process of manufacturing decorative laminates by impregnating the modified cellulose paper core with an aqueous solution of phenolic resin containing flame retarriant and decorative paper saturated with melamine formaldehyde resin solution. C and further processing

The layer comprising the core of the layer and the decorative layer at temperatures between 130 and 150 ° C at a pressure of between 7 and 50 bar, characterized in that the cellulose paper core containing 5 to 30 wt. % of ammonium, calcium or magnesium polyphosphates, or mixtures thereof, is impregnated with an aqueous solution of a phenolic resin resol condensed in the presence of divalent metal oxides, for example magnesium oxide, the solution containing 5-15 wt. polyphosphoric acids having at least three phosphorus atoms and a solution of aliphatic primary, secondary and / or tertiary amines or 0-hydroxylamine in aqueous ammonia or methanol, adjusting the pH of the phenolic resin resol solution to pH 7 to 0 and impregnating the decorative paper a melamine-formaldehyde resin solution containing from 5 to 10 wt. % of metaphosphoric acid and a methanol solution of O-hydroxylamine, the pH of the melamine-formaldehyde resin solution being adjusted to a pH of 0 to 9.

The burning process of the above-described laminates, where polyphosphorus compounds have been used to retard the combustion, proceeds differently from other known slow-burning laminates. Polyphosphoric acids are predominantly a mixture of higher open chain tripolyphosphoric acids or cyclic acids or salts thereof. The introduction of phosphorus into the condensed form has a great effect on the burning mechanism: phosphoric acid tends to decompose directly at an early stage to produce non-volatile products of much greater molecular weight, which are subject to further destruction and provide large amounts of primary organic carbon in the form of carbonaceous residue and small gases using polyphosphoric compounds. Reaction of phosphoric acid or its anhydride with carbonaceous residues at the decomposition stage limits carbon oxidation. Further, the bound phosphorus provides a glass coating on the surface of the burning material limiting oxygen access and creating a barrier to flammable carbon oxides or other volatile flammable substances.

In the oxidation of carbon, phosphorus is reduced. This is an exothermic reaction associated with the absorption of heat from the combustion process. Furthermore, the metal oxides used in the condensation of the resin form complexes with phosphorous groups and contribute to reducing the likelihood of burning by the formation of mechanical constituents that prevent oxygen access. The poor aqueous solubility of polyphosphorous compounds, due to the low percentage of hydroxyl groups, is another advantage that ensures low water absorption by the laminate.

This parameter is very important for products used in shipbuilding. It is also possible to use these laminates in different climatic conditions.

The following examples illustrate the present invention.

Example 1

The coating tank of the impregnating machine is filled with an aqueous solution of a phenolic resin condensed in the presence of magnesium oxide containing 10% by weight of polyphosphoric acid and a solution of triethanolamine in methanol. The solution has a pH of 7 to 0 and its viscosity is measured in a Ford Cup # 4 for 00 to 100 seconds. A blend of cellulose paper containing mass is passed through this mixture. 10% by weight of ammonium polyphosphates, 32 to 39% by weight of the carrier are thus applied to the support. resin. The paper is then passed through a drying tunnel downstream of the impregnating machine, 6 to 0 wt. volatile particles. The paper carrier is then cut into sheets of the desired size, which are stacked together with sheets of unmodified decorative printed cellulose paper saturated with a solution of melamine formaldehyde resin, and the layer is heat treated like the paper core. They are then pressed for 5 minutes in a known manner at a temperature of 140 to 145 [deg.] C. at a pressure of 7 to 50 bar until the layer thickness is 1 mm.

Example 2

The pulp web is passed through an impregnation varnish tank, which is filled with an aqueous solution of a phenolic resin condensed in the presence of magnesium oxide at pH 0 and a viscosity of 00 to 120 seconds measured by the meta of the Ford spout cup,

CS 274 460 02

containing 20 wt. % polyphosphoric acid and a solution of O-hydroxylamine in aqueous ammonia. Once the resin content of the carrier is 32-39% by weight, the web is passed through a drying tunnel in the heating zone of the impregnation machine, up to a content of 6 to 4% by weight. volatile substances. The paper carrier is cut into sheets of the desired size and stacked together with the decorative cellulose paper sheets, the layer is saturated with a melamine-formaldehyde resin solution of pH 3 containing 5% by weight. and a solution of O-hydroxylamine in aqueous ammonia. It is then heat treated in the same manner as the paper core.

The layer is then pressed for 5 minutes to a thickness of 1 mm in a known manner at a temperature of 140 to 145 ° C under a pressure of 7.85 to 8.83 MPa.

Example 3

Cellulose paper strip containing 15 ¾ wt. The mixture of ammonium, calcium and magnesium polyphosphates is passed through an impregnation machine varnish filled with an aqueous rosin of a gel resin of condensed resin in the presence of magnesium having a pH value of 7 to 8 and a viscosity of 00 to 120 seconds measured by Pord Spout No. 4 to a resin content of 32 to 39% in a saturated carrier. The strip is then passed through a drying tunnel of the impregnation machine until it contains 6-8 wt. volatile substances.

This paper carrier is cut into plates of the desired size, which are laminated to decorative paper plates which have been saturated with an aqueous solution of melamine formaldehyde resin and heat treated in the same manner as the paper core. The layer is pressed for 5 minutes to a thickness of 1 mm by known methods at a temperature of 145-150 [deg.] C. under a pressure of 7.83 MPa.

The laminates produced by the process according to the invention can be used wherever there is even a low risk of fire which, if laminates prepared according to the known methods, can have catastrophic consequences.

Claims (1)

A process for producing decorative laminates by impregnating a modified cellulose paper core with an aqueous solution of a phenolic resin containing a flame retardant and decorative paper saturated with a solution of melamine formaldehyde resin, drying the impregnated paper layers at temperatures between 120 and 140 ° C and further treating the layer containing the core and decorative layer at a temperature between 130 and 150 ° C at a pressure of 7.85 and 0.85 MPa, characterized in that the cellulosic paper core with a content of 5 to 30 wt. % of ammonium, calcium or magnesium polyphosphates, or mixtures thereof, is impregnated with an aqueous solution of a phenolic resin condensed in the presence of divalent metal oxides, e.g. polyphosphoric acids having at least three phosphorus atoms, and a solution of aliphatic primary, secondary and / or tertiary amines or O-hydroxylamine in aqueous ammonia or methanol, adjusting the pH of the phenolic resin resol solution to pH 7-8 and then decorative paper impregnated with a melamine-formaldehyde resin solution containing 5 to 10 wt. % of metaphosphoric acid and methanolic solution of O-hydroxylamine, the pH of the melamine-formaldehyde resin solution being adjusted to a pH of 8-9.