FI86902B - FOERFARANDE FOER FRAMSTAELLNING AV PAPPERSBANOR IMPREGNERADE MED KONSTHARTSER I FORM AV LOESNINGAR ELLER DISPERSIONER. - Google Patents

Abstract

A description is given of the soaking or impregnation of a paper web consisting mostly of cellulose fibres by a combination of dispersions and solutions of synthetic resins in a roll-type application unit installed in the papermaking machine, where the nature, degree of beating and dispersion particle size and the mixing ratio of dispersion and solution are matched to one another, for the manufacture of a fibre-containing sheet, in particular for covering parts of furniture.

Description

! 86902

The present invention relates to a process for the preparation of paper webs impregnated with artificial resins in the form of solutions and dispersions.

It is common and known to coat or clad televisions, radios, Hi-Fi equipment and furniture parts entirely with an artificial film. PVC films of different thicknesses are preferably used for this purpose.

10 These PVC films are glued, for example, on chipboard, and then, according to the principles of furniture technology, furniture parts or housings are made from this joint material in one work step, i.e. V-shaped grooves are cut in the chipboards and then the boards are folded or bent, thus enclosing casings, furniture parts or the like in one step.

In this method, it is important that no film tears form on the fold line. In this method, it is disadvantageous that the PVC film must be subjected to a suitable surface treatment, for example a corona treatment, immediately before use in order to achieve good printability.

,; In addition, particle board must have a very clean and smooth surface in order to achieve results that are still economically defensible (coating with thin films).

However, it is very disadvantageous that the PVC film has a very unfavorable dimensional stability (elongation / shrinkage *: attitude) when temperature changes occur, low tear strength, low light aging inhibition, high electrostatic charge and softening already occurs at 75-85 ° C. In addition, when heated above 120 ° C, HCl separates.

It is therefore an object of the present invention to provide 55 film-like, artificial! s i-length, web-like material which does not have the disadvantages of a plain plastic film used in the usual way, which also has good flexibility, water resistance, 2 86902 resistance to solvents and also has good internal strength and good dimensional stability under the influence of humidity and temperature changes.

In addition, the web-like material must be able to be prepared from the preferred raw materials in an economical manner and, if possible, without any additional process steps, with the exception of the production of the calendered paper web itself.

It is known from the literature, for example from DE-PS 25 50 980, to impregnate a raw paper web and impregnating aqueous resin solutions and / or impregnating resin dispersions by sucking impregnating liquid for impregnation in a suction area 15 above, where the impregnating liquid is sucked to another surface. However, impregnating resin solutions are based on urea, melamine and phenolic resins and formaldehyde content and lead to brittle products.

In this method, it is necessary to pass the base paper-20 web after its manufacture to another device and disassemble · *. to roll from impregnation, using accessories such as! suction area and dryer and re-roll it.

In addition, in this method, the distribution of the impregnating liquid over the cross-section of the paper is uneven, so that more strongly impregnated areas are formed adjacent to the less impregnated areas, which may result in the distribution of the inside of the paper.

DE-05 24 394 describes a method for producing artificial veneers in a paper machine, in which the paper web in the drying section is provided with impregnation which takes place in a gluing press. However, the impregnation of the paper web with an impregnating liquid not shown in more detail is complete only when the paper web has already been pre-prepared, so that additional devices are also required here as well.

3 86902 when, in addition to the choice of a suitable application and impregnation device, the properties of the paper, such as grinding space and degree of grinding, fiber absorbency, porosity and surface roughness of the impregnation or coating composition, properties of the impregnation or coating composition, its surface tension, viscosity, state of charge and dry matter content are balanced.

According to the invention, this problem is now solved by making a paper web from a high-absorbency and high-strength elastomer fiber blend ground to a degree of refining of not more than 35 ° SR, the impregnating liquid consisting of a mixture of aqueous anionic copolymer dispersions and aqueous anionic solutions having a pH of between 7 »5 and 10 and that the application is carried out with a gluing press in the drying section of the paper machine. Preferably 15 the pH is between 8 and 9 ·

The cellulose of the paper web according to the invention is preferably eucalyptus and pine cellulose in a ratio of 50:50 to 10:90, most preferably 30:70 to 15:85. The degree of grinding is preferably between 15 and 25 ° SR.

20 Chemical auxiliaries such as wet and dry solids, precipitants, synthetic resin dispersions, surfactants, colorants and fillers that alter the properties of the base paper can be added to the fibrous material of the paper web.

Fillers include white pigments such as TiCl 4, chalk and kaolin.

A formaldehyde-free wet solid in an amount of 1 to 5% by weight has proven to be very advantageous for the purpose of the invention. dry fiber, for example 30 polyamines in the form of a n-epichlorohydride nibart, and an addition of a resin based on a resin, e.g. a resin based on acrylic acid ester or styrene-butadiene, in an amount of 1-20% of dry fiber and a small addition of surfactants for better wettability of the paper less than 0.5% of dry matter-55.

The aqueous anionic copolymer dispersion, which may consist of a dispersion based on vinyl acetate and / or styrene, e.g., acrylic acid, so-called acrylic acid, so-called acid esters, in the use according to the invention, the particles dispersed in the invention are preferably smaller than 0.2 μπ. the hardness of the film is lower than the average hardness of the film, and the lowest formation temperature of the film 5 is preferably less than 30 ° C.

The ratio of both copolymers of the dispersion and the solution is preferably 500: 1 to 1: 1, most preferably 100: 1 to 10: 1 of the active ingredient, i.e. 500 parts of dispersion per 1 part of solution up to 10 parts of dispersion per 1 part of solution.

Within the scope of the present invention, it is also possible to add other active ingredients, e.g. styrene-butadiene copolymers, polyurethane or polyolefin dispersions and impregnating resin solutions based on urea or melamine-formaldehyde resins, in proportions to the impregnating agent.

By using the mixture according to the invention together with a portion of an absorbent resin solution, the brittleness of the impregnated paper can be reduced.

.'Other impregnating agents may also be added to these impregnating compositions, such as wetting agents, viscosity modifiers, anti-infectives and penetration aids, pigments, colorants and defoamers.

Wetting and penetration agents are substances which change the liquid and solid phase, e.g.

25 interface tension between surfactants and emulsifiers.

According to the invention, the penetration of the impregnating liquid can be advantageously effected by a combination of maleic acid copolymers and interfacial tension modifiers.

According to the invention, this impregnating agent is used as a solvent. and a dispersion with a dry matter content of 5 to 60%, with a viscosity of between 10 and 60 s (according to DIN-Becher, 4 mm), n Application of this impregnation and coating mixture on a fibrous gauze takes place inside a paper machine in a roller applicator (gluing press). In this case, according to the invention, the fibrous gauze is passed through a condenser at a dry matter content of 98-92% and thus reciprocally absorbed.

According to the invention, after this first process step of impregnation, a second one-sided or two-sided surface covering can be performed, i. coating the fibrous gauze inside the paper machine with a similar or similar copolymer blend, in which case intermediate drying must take place between the two process steps.

Subsequent coating on the other surface of the dried web provides a dense surface which provides good printability, varnishability or gluability. If only a second single-sided surface coating is performed, this can be performed with a sweeping blade device. One-sided winding of the described paper web can be avoided by applying li-15 to the back side.

Such a coating may be, for example, a strong aqueous solution of starch or CMC. Further smoothing of the impregnated and unilaterally coated web, e.g. with known machine polishing devices or in a separate work step in fish-blades, further increases the printability and varnishability of the coated surface.

This fibrous film made in this way has a different thickness and different raw density of gauze ... in the manufacture and impregnation or coating of web gloss; 25 depending on the pressure used in the lottery, - · for a fixed connection compared to a hard and rigid base, eg chipboard, decorative parts of furniture, such as TV and radio enclosures or H-Fi equipment. sex and protective cladding (enclosure cladding). Use-. . · ‘30 by using this economically advantageous fiber • _ ·. The twelve films avoid the disadvantages mentioned at the beginning when using a PVC film or other synthetic film.

The fibrous film according to the invention, which has a high or wood, inertia temperature change and good water resistance against water and solvents, is advantageously also suitable for other purposes, such as, for example, a large wet grinding, printing and finishing material for valuable abrasive papers. for advertising publications, decorative wall materials (for example for non-flammable pigmented or non-pigmented dimensionally resistant wallpapers) and for adhesives and carrier papers for e.g. floor coverings.

The invention will now be explained in more detail with reference to examples.

Example 1 According to the invention, a base paper having the following composition and structure was prepared as a two-ply paper on a Duplex paper machine: 80% pine sulphate cellulose 20% eucalyptus cellulose 15 degree of grinding 30 ° SR (Schopper-Riegler) additions of commercially available (calculated on 3% dry cellulose) 1% formaldehyde-free wet solid 20 0.3% wetting and dispersing agent 2. This base paper with a basis weight of 90 g / m 2 was impregnated on both sides with a 20: 1 mixture of dispersion and solution artificial resin according to the invention in a size press. The surprisingly strong impregnation effect of the synthetic resin mixture according to the invention, which is very characteristic in terms of layer strength and stiffness, in this case, taking into account the future water absorption, depends on the synergistic effect of the dispersion and the solution used, which alone cannot 30 get almost the same desired good paper properties.

The following examples confirm this. The adhesive solutions had to be partially adjusted with water to the optimum viscosity (<60 s according to PIN-Reeher), 4 mm).

.: · 53 Ii suction press - selection instructions: 1 - Artificial resin dispersion alone (aqueous anionic copolymer dispersion based on acrylic acid esters, acrylonitrile and styrene) with a dry matter content of 50%, average grain size approx. 0.1 m , average film hardness, lowest film formation temperature below 1 ° C.

5 2 - Artificial dispersion, diluted with water, dry matter content 25%.

3 - Active substance solution alone, diluted with water (anionic aqueous solution of a carboxyl group-containing copolymer based on maleic anhydride), with a dry matter content of about 12%.

4 - Active substance solution with formaldehyde-free wet solid, diluted with water, dry matter content about 10%.

5 - A mixture of active ingredients according to the invention consisting of a dispersion (according to Example 1) and a solution (according to Example 3) in a ratio of 20: 1, - with additions of a formaldehyde-free wet solid and - defoamer, diluted with water to a dry matter content of about 25%.

20____

Paper properties- Basic Basic paper, gluing press- · det paper with manufacturing instructions (solution 2 • a reception approx. 15 g / m) _1 2_3 4 5 25 Layer strength 550/660/1050/525/560/1125 / transverse ^ g / cm ? 5 88 140 75 155 Stiffness, longitudinal> 3.50 3.32 2.83 2.56 2.89 2.30 (Kodak-Pathe), mNxm water absorption> 200 23 28 27 26 25 g / m2

However, due to its good film-forming properties, the artificial resin dispersion alone (Preparation 1) reduces the water absorption as much as possible, so that the penetration into the base paper is insufficient. This is evidenced only by the insignificantly improved values for 8 86902 ί layer strength and stiffness. j Dilution of this dispersion with water (preparation instructions! ϊ 2) results in a stronger penetration into the base paper at the same time as the absorption of the increased water and the elasticity of the impregnated paper are still insufficient.

In addition, incomplete impregnation is seen in the insufficient Vidin strength (Ribbelfestigkeit) of the paper surface. Impregnation of the base paper with a water-diluted resin solution (Preparation 3) does lead to improved elasticity, but at the expense of greatly reduced layer strength.

Also, the addition of a wet solid (manufacturing instruction * 1) does not cause a substantial change in the property of the impregnated paper.

Only the artificial resin mixture of the dispersion and the solution according to the invention (Preparation 5) achieves the desired high impregnation effect of the adhesive solution and thus all the desired good paper properties, characterized by about 10% higher layer strength than Preparation 2, 20 relatively low water absorption and maximum elasticity. (about 10% lower stiffness than when using preparation instruction 3).

According to this effect of the individual components (dispersion, solution, wet-solid), no excess is expected. The high saturation effect must be considered to be due to the combined effect of dispersion and solution.

Example 2

In another set of experiments, the medium hard synthetic resin dispersion (5) was replaced by a hard dispersion with a grain size of about 0.15 μm and a minimum film formation temperature of about 25 ° C. This dispersion was an aqueous copolymer dispersion based on an acrylic acid ester and styrene.

This gave the following properties of the impregnated base paper (the results obtained from Test Set 1 above in Preparation 5 are presented for better comprehension once again): 5 86902

Paper properties- Basic Basic paper, gluing press-det paper with manufacturing instructions (solution p reception approx. 15 g / m) 5________5 6_7_

Tell :; strength 550/1125/860/1110 / longitudinally itc τίιο transverse, g / cm 75 150 115 11.8 Stiffness, longitudinal> 3.50 2.30 3.10 2.76 jq (Kodak-Pathe), mNxm water absorption> 200 25 28 23 g / m2 6 - Artificial resin dispersion, diluted with water, with the addition of a formaldehyde-free wet solid, with a dry matter content of about 25%.

7 - The synthetic resin mixture according to the invention, consisting of a dispersion and a solution according to Example 3 in a ratio of 20: 1, - with the addition of a formaldehyde-free wet solid and 20 - of a defoamer, was diluted with water to a dry matter content of about 25%

The artificial resin dispersion according to Preparation 6 alone, as has already been shown in Preparation 1 and 2, did not achieve the desired good impregnation effect. Only the combination of dispersion and solution according to the present invention, on the other hand, results in the desired paper properties. Due to the high hardness, the elasticity of the impregnated paper remains inferior to that of the preparation step 5 · · 30 According to the present invention, the subsequent salinization of the impregnated papers reduces the stiffness by about 10-20% and the water absorption by about 15-20%> while the layer strength remains almost unchanged.

35 Example 3

In the following series of experiments, a synthetic resin mixture of the dispersion and solution according to the invention was used in combination with carbam 86902 midi-formaldehyde resin in a ratio of 2: 1 to impregnate the base paper according to Example 1.

8 - The synthetic resin dispersion according to Preparation 6 alone in combination with a urea-formaldehyde resin in a ratio of 2: 1.

9 - The synthetic resin mixture according to the invention, which according to the preparation instructions 7 consists of a dispersion and a solution (in a ratio of 20: 1) in combination with a urea resin in a ratio of 2: 1.

10 10 - Artificial resin dispersion alone (aqueous anionic copolymer dispersion based on acrylates), dry matter content 50%> average grain size about 0.15 μm, average film hardness and lowest film formation temperature 12 ° C in combination with urea-formaldehyde resin 2 : 1.

11 - A synthetic resin mixture according to the invention, consisting of a dispersion (according to Preparation 10) and a solution (according to Preparation 3) in a ratio of 20: 1 in combination with a urea resin in a ratio of 2: 1.

20 The obtained properties of the impregnated paper are summarized in the following table.

Paper properties- Basic base paper, gluing press- [. · 'Det paper with tin manufacturing instructions:: 25 (dry matter content%) _8_9_10 11

Reception of the solution - 17 18 26 28 to g / m2

Porosity, cm 2 / min 160 114 76 140 9 ^ 30 Water absorption g / m2> 200 26 20 87 27

Layer strong new, 6 * 1 126 1 ^ 6 133 1 * 1 * 1 transversely, g / cm

Also, combinations of synthetic resin dispersions and impregnating resins, such as bear and resins, as are common for impregnating decorative papers in separate impregnations, will result in an improvement in the properties of the base paper. In this case, the type of synthetic resin dispersions used essentially determines the solution uptake, porosity, water absorption and layer strength of the paper (see Preparation Instructions 8 and 10).

However, it is only with the artificial resin mixture according to the invention of the dispersion and the solution that the desired high impregnation effect of these special impregnating resin combinations and thus the desired properties of the impregnated paper are also achieved (see preparation instructions 9 and 11). In addition to this, there is, for example, a considerable decrease in porosity and water absorption and an increase in layer strength. However, due to the relatively high proportion of impregnating resin, the level of layer strength is slightly lower than in the case of Manufacturing Instructions 1 and 2.

Claims (9)

1. A process for producing paper webs impregnated with artificial resins in the form of solutions and dispersions, characterized in that the paper web is made of a strong cellulose fiber mixture with good suction capacity, which is ground to a degree of grinding of not more than 35 ° SR, Surface coating agents for treating the fibrous web are used ordinary aqueous, anionic copolymer dispersions, the pH of which is between 7.5 and 10 and is based on acrylic acid, acrylic acid ester, acrylonitrile, vinyl acetate and / or styrene and which have an average granule size below 0.2 µπι fr. to the medium to medium membrane hardness and the lowest membrane formation temperature below 30 ° C as a combination of ordinary aqueous, anionic copolymers based on the maleic anhydride or maleic acid, together with ordinary aqueous anionic solutions together with .ex. styrene, acrylic acid, the acrylic acid ester and the like. in the ratio of 100: 1 20 - 10: 1 (based on the active agent), preferably 25: 1 - 15: 1 and together with other additives, such as curing agents, viscosity regulators, grip preventants and penetration aids and pigments and dyes. 25 Process according to claim 1, characterized in that the pH is suitably controlled in the range 8-9. Method according to claims 1 and 2, characterized in that the paper web's cellulose 30 is made of eucalyptus cellulose and pine sulfate cellulose in the ratio 50:50 - 10:90, preferably 30:70 -15: 85, optionally as a combination with synthetic fiber material. rial and preferably is continued to be screen-milled to a grinding degree of 15-25 SR. 35 Method according to claims 1-3, characterized in that chemical auxiliaries such as pH controllers, the hydrogen and dry solid, artificial resin 86902 dispersions, precipitating agents (surfactants), surfactants, coloring agents are additionally added to the paper web fiber material. , fillers and the like. Process according to claims 1-4, characterized in that the mixture comprising the dispersion and the mixture additionally contains a surfactant fraction. Process according to claims 1-5, characterized in that the proportion of the surfactant, calculated from the mixture of the dispersion and the solution, is 0.05-1.5%. 10 Method according to claims 1-6, characterized in that the penetration of the web of fibrous web is carried out within the paper machine in the first process stage from both sides by means of a roll disk and the coating in the second process stage from one side by means of spreading. Method according to claims 1-7, characterized in that the paper web is subjected to a second surface treatment, such as coating, printing and / or varnishing, of the other side after drying and calendering. Use of a dried paper web manufactured in accordance with claims 1-8 for the coating of furniture (protective covering) by gluing it onto a rigid base and by further processing the so-obtained combined material by placing oblique incisions and folds in the area of the oblique cuts at parts of three-dimensional furniture (folding corpus).