EP0318751A2 - Finishing agent for natural and synthetic leather - Google Patents

Abstract

Finishing agents for natural and synthetic leather contain solutions of cellulose acetobutyrate having a butyryl content of >/= 45 % by weight.

Description

The invention relates to finishing agents for leather and imitations of leather, processes for finishing leather or imitations of leather and finished leather and imitations of leather.

Finishes serve to improve the physical fastness of leather and imitations of leather, such as rub fastness, shock resistance and heat resistance. In addition, they give these materials a solid external appearance such as shine, smoothness and surface feel. Finishing agents for leather and imitations of leather are already known in large numbers, e.g. based on protein substances, nitrocellulose and polyurethanes.

Dressings with ever higher fastness properties are increasingly required by the leather processing industry. Upper shoe leather and especially those types of leather that need to be coated thickly, such as split leather and sanding box, should be very good wet and rub-through resistant; a dry kink resistance of at least 100,000 flexometer values and a wet tensile strength of 20,000 flexometer values according to SATRA are aimed for. White and pastel-colored leather are said to have particularly good kink resistance, because even the finest hairline cracks due to dirt deposits are clearly visible on light-colored shoes when worn. The following additional requirements are also placed on light-colored leather: they should be lightfast and amine resistant. The amine resistance is particularly important for furniture leather, since foam materials based on PUR for furniture sets often still contain free amine. Light-colored leather should also be heat-resistant up to 170 ° C and not yellow, because these temperatures occur on the shoe upper when the soles of the shoes, for example made of PVC and PUR, are molded on.

These authenticity requirements in practice can largely be met for thermoplastic primers if highly crosslinked polymer dispersions are used as binders when dressing the leather, or even better, if reactive binders are crosslinked on the leather using suitable polyfunctional compounds (see, for example, DE- OS 3 544 001 and DE-OS 3 711 415). Primers with such strongly crosslinked polymer dispersions, however, seal off strongly and are therefore only slightly swellable by water and solvents. The adhesion of the finishing layers is therefore problematic. Finishing agents that are to be applied to cross-linked reactive primers must therefore have particularly good adhesion to the substrate.

The use of protein-based finishes is limited to only a few types of leather with a low coating thickness. The finishes must be fixed with formaldehyde. For most types of leather, especially for the heavily covered types with reactive primers, the finishing film is not elastic enough and gives only very moderate rub fastness and kink resistance.

Lacquers based on collodion have good adhesion to reactive primers. As is well known, nitrocellulose has many valuable properties that make it suitable as a finishing agent, but also has disadvantages: low lightfastness, non-resistant to amines, not heat-resistant and extremely flammable. These disadvantageous properties make collodion varnishes unsuitable for finishing white and light-colored leathers.

Polyurethane paints only adhere to primers with reactive binders if they are used in the form of reactive two-component paints. Disadvantages for all PUR lacquers of both the 1- and the reactive 2-component lacquers are a leather-like, plastic-like handle and their low pigmentability; they can only be weakly pigmented, otherwise poor wet rub fastness results. PUR lacquers are therefore ruled out as highly opaque final finishes, especially for light-colored leather.

In recent years, cellulose acetate butyrate-based paints have also been used as a finishing agent for white and pastel-colored leather. The lacquers can be pigmented more strongly than PUR lacquers without poor wet fastness being observed; they are lightfast, amine-proof, resistant to yellowing up to 170 ° C and give flame-retardant residues. The main disadvantages of the cellulose acetobutyrate lacquers previously used for leather finishing are their poor adhesion, their poor absorption capacity for plasticizers and their unpleasant feel. So these finishing agents do not adhere to primers that are heavily finished by hot ironing or embossing of damp leather, long, hot drying or long storage of the leather during the dressing process (holidays) or also by strong polishing effects. After all, these paints also do not adhere to primers with crosslinked reactive binders. But reactive primers are becoming more and more important because they are used to make finishes with a very good aspect and a particularly high level of authenticity.

The adhesion of the known finishing agents based on cellulose acetobutyrate for leather finishing is further deteriorated if pigments are added to them or inorganic matting agents, such as porous orthosilicic acid, are added to them. Any type of plasticizer additive is particularly detrimental to adhesion. Soft and elastic leather can be used with the lacquers currently used for leather finishing Acetobutyrates as binders are not finished, because for these types of leather to adjust the required smoothness of the finishing film such high amounts of plasticizers are required that sufficient adhesion of these finishing agents is no longer guaranteed, even on poorly finished primers. The grip of finishes with acetobutyrates as binders without plasticizer additives is cold, smooth, plastic-like and absolutely foreign to leather. If plasticizers are added to these finishes, the cellulose acetobutyrate types used repel most of these products to the surface of the finish layer, causing an undesirable, sticky feel.

Attempts to increase the adhesion of the common finishing agents for leather finishing with cellulose acetobutyrates as binders by adding high-boiling solvents such as cyclohexanone, ethyl glycol acetate, diacetone alcohol do not lead to any improvement. The addition of such resins or polymers, which have proven themselves as adhesion promoters in other finishing binders, such as, for example, alkyd resins, urea and melamine resins, condensation products made from aromatic hydrocarbons and formaldehyde or polyacrylates do not improve, but on the contrary, deteriorate the adhesion. In addition, such products, like plasticizer additives, are partially repelled by the cellulose acetobutyrate types used in the known finishing agents and thereby cause an unpleasant surface grip.

It has now been found that finishing layers on leather and imitations of leather with particularly good properties important for leather finishing, such as grip, gloss, toughness, low-temperature flexibility, dry and wet rub fastness, dry and wet kink resistance, good flow during spraying, but especially good adhesion Strongly sealed primers and high absorbency for plasticizers, pigments and matting agents are obtained when using finishing agents which contain solutions of cellulose acetobutyrate types which have a butyryl content ≧ 45% by weight, based on cellulose acetobutyrate, preferably 45 to 55% by weight. , particularly preferably 47 to 53% by weight. The 20% solution of the cellulose acetobutyrate in acetone used according to the invention should preferably have a viscosity of 0.1 to 40 poises at 20 ° C.

enthalten,
wobei PE für einen Polyetherrest steht und R z.B. fol­gende beiden Strukturen haben kann:

R′ = ein Alkyl-, Cycloalkyl-, Alkenyl-, Aralkyl-, Dialkylaminoalkyl-, Aryl- odr Alkarylrest mit jeweils bis zu 10 Kohlenstoffatomen
oder

x = 2-25.The finishing agents according to the invention preferably also contain polyether siloxanes, in particular polyether siloxanes, in which the ether groups are bonded to the polysiloxane via ether bridges or carbamic acid ester groups, for example polyether siloxanes, which have at least two groups of the structure

contain,
where PE stands for a polyether residue and R can have, for example, the following two structures:

R '= an alkyl, cycloalkyl, alkenyl, aralkyl, dialkylaminoalkyl, aryl or alkaryl radical each having up to 10 carbon atoms
or

x = 2-25.

Such products are made by known methods, e.g. according to DE-OS 1 905 101 or DE-OS 3 244 955 (Examples 1A, 2A, 3A).

The cellulose acetobutyrate to be used according to the invention is produced by methods known per se, e.g. by esterification of cellulose in the form of cotton internals with acetic and butyric anhydride, in the presence of pyridine.

The finishing agents according to the invention can also contain plasticizers, blending agents and others for finishing agents common to leather and imitations of leather, contain additives, for example matting agents, pigments and other additives.

As plasticizers come e.g. Phthalates, phosphates, esters of aliphatic dicarboxylic acids, fatty acid esters and polymeric plasticizers in question.

Mixtures of n-butyl stearate with diesters of phthalic acid are preferably used, in particular di-n-butyl phthalate, di-n-hexyl phthalate, di-n-octyl phthalate or dibenzyl phthalate in a ratio of 1: 1 to 1: 3, preferably 1: 1.2 to 1: 2.4.

As a solvent or extender for the finishing agent according to the invention, e.g. Alcohols, ketones and acetates are suitable, in particular suitable are: acetone, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methoxypropanol, butyl acetate, methyl and ethyl glycol acetate, methoxy and ethoxypropyl acetate, butyl glycol acetate, cyclohexanone and diacetone alcohol.

It has been shown that toluene, xylenes, isopropanol, ethanol, methyl and ethyl glycol, benzyl alcohol, diisobutyl ketone and in particular 2-ethyl-n-hexylacetate are particularly suitable as solvents or blending agents. For ecological reasons, alcohols and glycols are preferred. The physical properties of the finishing agents such as flow, drying speed and the like are due to the amount of low boilers (isopropanol, ethanol), medium boilers (methyl, ethyl glycol) or high boilers (benzyl alcohol, 2-ethyl-n- hexylacetate) controllable. They are used in amounts from 0 to about 985 g / kg of finishing agent. The use of other solvents is of course within the scope of the invention.

To produce the finishing agent, the components are combined with solvents and blending agents and stirred until the cellulose acetobutyrate has completely dissolved.

Particularly good results are obtained with a finishing agent which contains 15 to 40 g of cellulose acetobutyrate with a butyryl content of ≧ 45% by weight per kg.

The polyether siloxane is preferably used in amounts of 0.5 to 20 g / kg, preferably 0.5 to 10 g / kg of finishing agent.

The plasticizer or the plasticizer mixture is preferably used in amounts of 0 to 100 g / kg, preferably 5 to 80 g / kg, of finishing agents. It is particularly advantageous to use a plasticizer mixture of 2 to 20 g of n-butyl stearate and 3 to 30 g of di-n-butyl phthalate and / or di-n-octyl phthalate per kg of finishing agent.

The preparation of white, colored and matted finishing agents can be carried out, for example, by adding only a part of the solvent / extender mixture to the cellulose acetobutyrate, the polyether siloxane and the plasticizer, so that a paint consistency which is favorable for the dispersion of the pigment is obtained becomes. After the pigment or the matting agent has been introduced into the lacquer, the mixture is stirred using a dissolver at 800 to 2000 rpm until the pigment is finely divided and, if appropriate, ground in a bead mill with cooling. Before applying to leather, the remaining amount of solvent and blending agent is diluted further.

The finishing agents are applied by spray application, by means of a casting machine, knife or roller application machine to full-grain, sanded or split leather, which has been treated with pigments and thermoplastic binders, and to imitations of leather and textile material coated with polyurethane. Primers for leather finishing that can be treated with the finishing agent according to the invention are described, for example, in Ullmanns Encyklopadie der Technische Chemie, 4th edition, volume 16, pp. 161-166.

The finishes can also be applied in several layers, if desired, varying their composition.

After drying, the finished materials can be ironed and polished.

The finishes run particularly well, especially when spraying, and give hardly inflammable residues. They are lightfast, amine-proof and resistant to yellowing up to 170 ° C and are characterized by a very good Liability from. Thus, they adhere to primers which have been severely finished by hot ironing or long storage of the leather prior to finishing, but in particular also to primers with crosslinked reactive binders produced according to DE-OS 3 544 001 or DE-OS 3 711 415. In comparison, PUR-based finishes do not adhere to such primers if they are not reactive, but only if they are used in the form of reactive two-component paints.

The leather finished in this way has good properties. You own with good surface calm, high gloss and a non-sticky, smooth, natural leather handle. In addition, the dry, wet and rub-through resistance and in particular the cold flexibility are more improved than with finishes based on protein, collodion and PUR.

Since the finishes can contain large amounts of the preferred plasticizer mixtures of n-butyl stearate and esters of phthalic acid without disadvantages for adhesion and grip, the finish film can be adjusted and pigmented almost as desired in terms of hardness and elasticity. The finishing agent according to the invention can thus be used for the entire broad range of leather types, from steady belt leather to soft, brisk nappa leather.

Pigments can be stained using a dissolver or a bead mill for a more suitable finish Viscosity, which can be controlled by the degree of dilution, is dispersed in the lacquer, or suitable, already formed pigments in paste form are used, produced, for example, according to DE-OS 2 801 817.

The pigments are selected according to the desired color effect. If high opacity is desired, inorganic pigments are preferably used. On the other hand, if the finish is to have a glazing color with high brilliance, organic pigments or organic solutions of 1: 2 metal complex dyes are preferably used, optionally in combination with inorganic pigments. In addition, the fastness properties specified by pigment or aniline dye, such as light and migration fastness and heat resistance, are taken into account for targeted use. If you strive for more or less matt finish layers, you use proportionate matting agents, e.g. based on silicon dioxide or aluminum oxide, which are incorporated into the finishing agent like pigments. If porous orthosilicic acid with a nominal particle size of 4 micrometers and a BET surface area of 260 m² / g is used for matting, the matt effects are particularly reproducible. The finishes do not show a gray break, cannot be polished back and have a natural leather handle. Furthermore, the scratch resistance of the finish is increased in this way.

Further advantages of the finishing agent according to the invention result from its extraordinarily high pig mentability without the wet rub fastness and the gloss decrease. Since the pigment / binder ratio can be greatly shifted in favor of the pigment compared to pigmented PUR varnishes, this varnish with comparable coverage layers much less than PUR varnishes, shows a finer scar throw, and in particular it sharpens the scar image while PUR varnishes smear the pore.

Of course, the finishing agent according to the invention can also be added to PUR paints, produced e.g. according to DE-OS 2 423 764 or DE-OS 1 694 141, in order to improve the property profile of these coating systems. Depending on the amount of the finishing agent added, more or less are improved: the flow, in particular in the case of high-molecular-weight polyurethane resins, grip, rub resistance, pigmentability and in particular the aspect: the leather appears less overloaded and plastic-like.

The invention further relates to leather and imitations of leather finished with the finishing agents according to the invention.

example 1

Chemicals Cellulose acetobutyrate, butyryl content 50% viscosity 20% in acetone at 20 ° C approx. 4 poises 22 g n-butyl stearate 3 g Di-n-butyl phthalate 6 g Polyether siloxane prepared according to DE-OS 3 244 955, Example 1A 4 g 2-ethyl-n-hexyl acetate 100 g n-butyl glycol acetate 65 g Methoxypropanol 400 g n-butyl acetate 400 g 1000 g.

The chemicals listed above are placed in a boiler in any order. The mixture is stirred at room temperature until the cellulose acetobutyrate has completely dissolved, giving a clear solution.

Sanded leather, full-grain leather and split leather, which have been trimmed with pigments and thermoplastic binders (cf. W. Grassmann, Handbook for Chemicals and Leather Manufacturing, Volume III / 1 and Ullmanns Encyklopadie der Technische Chemie, 4th edition, Volume 16, p. 161-166), as well as imitations of leather and textile materials coated with polyurethane, receive 1 to 2 spraying jobs with this varnish a total of 40 to 80 g / m². After drying, the finished materials can be ironed on a hydraulic ironing machine, eg at 70 ° C / 150 bar, or on a continuous ironing machine to regulate the surface smoothness and to adjust the gloss level.

The finishes have a very good course during spraying, are lightfast, amine-proof and resistant to yellowing up to 170 ° C. In particular, they are characterized by very good adhesion. For example, they adhere to primers which have been severely sealed by hot ironing or long storage of the leather before being finished, in particular they adhere to crosslinked primers with reactive binders, as described in DE-OS 3 544 001 and DE-OS 3 711 415, Examples 1 to 3, can be obtained.

The finished leathers are characterized by a high gloss with good surface quietness and in particular by a very natural leather handle. The dry, wet and rub-through resistance and especially the cold flexibility are more improved than when using finishing agents based on protein and collodion.

For staining with pigments, 20 g of a pigment paste, made according to DE-OS 2 801 817 and consisting of 3.4 g CI Pigment Red 170, 7.2 g pigment binder from DE-OS 2 801 817, are added to 1000 g of the colorless finishing varnish. Example 1, and 9.4 g of cyclohexanone and homogeneously distributed in the paint by stirring. The resulting intensely red-colored lacquer is applied to leather and imitations of leather that have been primed in a corresponding color, according to the above-described method. The varnish greatly improves the color uniformity and also gives the materials a high-gloss, brilliant colored aspect with good physical fastness.

For staining with aniline dyes, the finishing varnish can e.g. organic solutions of 1: 2 metal complex dyes can be added in a known manner.

Example 2

Chemicals Cellulose acetobutyrate, butyryl content 44%, viscosity 20% in acetone at 20 ° C approx. 20 poises 25 g n-butyl stearate 11 g Di-n-butyl phthalate 14 g Polyether siloxane prepared according to DE-OS 3 244 955, Example 2A 5 g 2-ethyl-n-hexyl acetate 100 g n-butyl acetate 100 g Titanium dioxide pigment (BAYER Titan R-FK-2, BAYER AG) 32 g Methoxypropanol 713 g 1000 g

Cellulose acetobutyrate, butyl stearate, dibutyl phthalate, polyethersiloxane, 2-ethylhexyl acetate and butyl acetate are placed in a kettle and stirred until a clear solution is obtained at room temperature. The titanium dioxide pigment is then introduced and stirred for 15 minutes at 1500 rpm using a dissolver. For the purpose of fine distribution of the titanium dioxide, the mixture is then ground once on a bead mill with glass beads of 1 mm in diameter with cooling. Then it is diluted to spray consistency. The ready-to-use white varnish is well dispersed, extremely opaque and easy to spray. It is lightfast, amine-proof and resistant to yellowing up to 170 ° C and adheres equally well to strongly sealed primers, e.g. with crosslinked reactive binders, such as the colorless lacquer in Example 1.

Sanded leather, full-grain leather as well as split leather or after imitations of leather, which have been prepared thermoplastic - as described in Example 1 - or coated with polyurethane, receive a spray application of about 25 to 50 g / m². After drying, the leather is ironed on a hydraulic press at 70 ° C and 150 bar or the imitation leather at 70 ° C and 50 bar. Then, under the same application conditions, a second application is carried out with the spraying machine. Total order 50 to 100 g / m². The white varnish gives the leather an extraordinarily natural leather character with strong coverage. This is because the pigment / binder ratio has shifted significantly in favor of the white pigment compared to pigmented PUR coatings, for example is, without the adhesion to the primer as well as the wet friction and the gloss have decreased, this varnish coats less than PUR varnishes with comparable coverage. Furthermore, the aspect of the finished leather has a favorable effect that good physical fastness properties, in particular wet, dry and rub-through resistance, can be achieved even with small amounts of paint and that, due to the high covering power of the white finish, color coats in the primer, which are associated with thermoplastic binders have been made and layers can be saved much more than the finishing jobs. For all these reasons, leathers that have been finished with this white varnish show a particularly fine grain due to the slightest stress on the leather surface. Despite their strong coverage, the leather has only a slight coating and is therefore very natural. Another advantage, which is particularly noticeable on full-grain leather and here especially on small animal skins, is the observation that the white lacquer described sharpens the scars, whereas a white lacquer based on PUR or collodion smears the leather pore.

For the production of pastel-colored finishes, for example 5 g of a pigment paste, produced according to DE-OS 2 801 817 and consisting of 3 g of lead chromate pigment (chrome yellow 601 L supra; from Siegel), 1.6 g of pigment binder are added to 1000 g of the above white lacquer from DE-OS 2 801 817, Example 1, and 0.4 g of cyclohexanone, and homogeneously distributed in the paint by stirring. Man receives a pastel lemon-colored varnish, which covers leather and imitations of leather that have been prepared in a corresponding color with thermoplastic binders, extremely strong and also makes ironing marks completely disappear. The finish gives the materials a good surface smoothness and a pleasant grip as well as good physical fastness. After the hydraulic ironing, instead of a second application with this lacquer, an application with the colorless lacquer described in Example 1 can be applied in order to increase the gloss even further and to reduce the sensitivity to metal objects, such as gold rings.

Example 3

Chemicals Cellulose acetobutyrate, butyryl content 52% viscosity 20% in acetone at 20 ° C approx. 0.8 poises 25 g n-butyl stearate 4 g Di-n-butyl phthalate 9 g Polyether siloxane according to DE-OS 3 244 955, Example 3 A 4 g 2-ethyl-n-hexyl acetate 100 g Butyl glycol acetate 50 g Porous, amorphous silica with a nominal particle size of 4 micrometers and a BET surface area of 200 m² / g 8 g Methoxypropanol 400 g n-butyl acetate 400 g 1000 g

Cellulose acetobutyrate, butyl stearate, dibutyl phthalate and the polyethersiloxane are clearly dissolved in ethylhexyl acetate and butyl glycol acetate in a kettle with stirring at room temperature. Finally, the silica is introduced and stirred vigorously for 15 minutes. Then the mixture is ground 1 time with glass beads of 1 mm diameter with cooling for the purpose of finely distributing the silica. Finally, the matt lacquer is diluted with methoxypropanol and n-butyl acetate to a sprayable consistency.

After application to leather and leather synthetics under the conditions of Example 1, a colorless matt finish is obtained which is scratch-resistant and cannot be polished back. It shows no gray opening and is characterized by a smooth, natural leather handle. Liability - even on strongly sealed primers - is perfect.

Example 4

In Example 1, the cellulose acetobutyrate used there is replaced by a cellulose acetobutyrate which is characterized by a butyryl content of 37% and a viscosity, 20% dissolved in acetone, at 20 ° C. of about 8 poises. The lacquer produced according to the method of example 1 and applied to leather and imitations of leather does not adhere to strongly sealed, thermoplastic primers, in particular not to crosslinked primers with reactive binders, produced according to DE-OS 3 544 001 and DE-OS 3 711 415, examples 1 to 3 .

Example 5

Chemicals Cellulose acetobutyrate, butyryl content 49% viscosity 20% in acetone at 20 ° C approx. 20 poises 35.0 g n-butyl stearate 5.0 g Di-n-butyl phthalate 16.5 g Polyether siloxane according to DE-OS 1 905 101, example 3 5.0 g 2-ethyl-n-hexyl acetate 162.5 g n-butyl acetate 87.5 g Addition product of about 20 moles of ethylene oxide with 1 mole of nonylphenol 2.5 g Gasoline fraction with high i-paraffin content; Bp. 145-200 ° C (SHELLSOL TD; SHELL) 25.0 g water 80.0 g Di-n-octyl sodium sulfosuccinate 1.0 g water 79.0 g Triethanolamine 1.0 g water 500.0 g 1000.0 g

The chemicals listed up to the SHELLSOL TD are dissolved in a kettle at room temperature with stirring. After complete dissolution, SHELLSOL TD is added all at once and stirred well for about 3 minutes. The solution of 1 g of di-n-octyl sodium sulfosuccinate in 80 g of water is then added with rapid stirring and, after the addition, stirred for a further 15 minutes. Here, the transfer takes place in an oil-in-water emul sion. Then 1 g of triethanolamine dissolved in 79 g of water is added with stirring and stirring is continued for a further 10 minutes. The remaining 500 g of water are finally added all at once. The pH of the finished emulsion is between 7 and 8.

Sanded and full-grain leather or even imitations of leather, which have been prepared thermoplastic - as described in Example 1 - or have been coated with polyurethane, are sprayed with about 10 to 30 g / m². After drying, the leather is ironed on a hydraulic press at approx. 70 ° C and 200 bar or the imitation leather at 80 ° C and 50 bar. A second application of 10 to 20 g / m² is then carried out under the same application conditions Spraying machine. This emulsion varnish gives the leather an extraordinarily natural leather character, especially in terms of grip and aspect, an advantage that is particularly noticeable on full-grain leather. In particular, leathers that are finished with such emulsions show a particularly fine grain scar due to the slightest load. In spite of a small order quantity, good physical fastness properties, especially fastness to kinking and rubbing, are achieved. In the coating, especially of imitations of leather, the lack of swelling of the substrate proves to be a particular advantage despite good adhesion due to the emulsion. As a result, a special fullness and surface calm with high gloss are achieved. Pigments and other dyes can also be added to this lacquer in a known manner analogously to Example 1.

Example 6

Chemicals Cellulose acetobutyrate, butyryl content 49% viscosity 20% in acetone at 20 ° C approx. 20 poises 35.0 g n-butyl stearate 15.0 g Di-n-butyl phthalate 20.0 g Polyether siloxane according to DE-OS 3 244 955, Example 1A 5.0 g 2-ethyl-n-hexyl acetate 162.5 g n-butyl acetate 87.5 g Addition product of about 20 moles of ethylene oxide with 1 mole of nonylphenol 5.0 g Titanium dioxide pigment (BAYER TITAN R-FK-2; BAYER AG) 45.5 g Gasoline fraction with high i-paraffin content; Bp. 145-200 ° C (SHELLSOL TD; SHELL) 25.0 g water 96.5 g Di-n-octyl sodium sulfosuccinate 2.0 g Triethanolamine 1.0 g water 500.0 g 1000.0 g

The chemicals listed above up to and including the adduct of about 20 moles of ethylene oxide with 1 mole of nonylphenol are dissolved in a kettle at room temperature as described in Example 5. 45.5 g of titanium dioxide pigment are introduced into the clear solution. After 15 minutes of vigorous stirring, the white dispersion is placed on a bead mill for the purpose of finely distributing the pigment ground 1 time with glass beads of 1 mm diameter with cooling. SHELLSOL TD is then added to the ground material and stirred well for about 3 minutes. Then the solution of di-n-octyl sodium sulfosuccinate in water is added with rapid stirring and, after the addition, stirred for a further 15 minutes. This is done by transferring it into an oil-in-water emulsion. Triethanolamine is then added and stirring is continued for a further 10 minutes. The remaining 500 g of water are finally added all at once. The pH of the finished white-pigmented emulsion is between 7 and 8. This emulsion is applied to white-trimmed leather and imitation leather according to the procedure of Example 2.

With equally good physical fastness properties, in particular good adhesion to closed primers and a comparable good coverage, the leather is even less stressed and therefore has an even more natural effect than leather with the white lacquer from Example 2. This white lacquer emulsion is particularly distinguished by the fact that the your treated leather and imitation leather get a very natural leather handle.

Example 7

Chemicals Cellulose acetobutyrate, butyryl content 49% viscosity 20% in acetone at 20 ° C approx. 20 poises 35 g n-butyl stearate 5 g Di-n-butyl phthalate 20 g Polyether siloxane according to DE-OS 3 244 955, Example 1A 5 g 2-ethyl-n-hexyl acetate 125 g n-butyl acetate 90 g Addition product of about 20 moles of ethylene oxide with 1 mole of nonylphenol 5 g Gasoline fraction with high i-paraffin content; Bp. 145-200 ° C (SHELLSOL TD; SHELL) 25 g water 75 g Di-n-octyl sodium sulfosuccinate 2 g Porous, amorphous silica with a nominal particle size of 4 micrometers and a BET surface area of 260 m² / g 15 g water 97 g Triethanolamine 1 g water 500 g 1000 g

The chemicals listed above are dissolved in a kettle at room temperature as described in Example 5 and the clear solution by adding di-n-octyl sodium sulfosuccinate, dissolved in water, with vigorous stirring in an oil-in-water Emulsion transferred. The silica is introduced into this emulsion. After 10 minutes of vigorous stirring, triethanolamine dissolved in water is added and stirring is continued for a further 10 minutes. The mixture is then ground 1 time in a bead mill with glass beads of 1 mm in diameter with cooling for the purpose of finely distributing the silica. The remaining 500 g of water are finally added all at once. The pH of the finished dispersion is between 7 and 8.

After application under the conditions of Example 5 to leather and synthetic leather, the dispersion gives a non-polishable matt lacquer that is scratch-resistant, shows no gray breakage and has an exceptionally smooth handle for the strong matting.

Example 8

In 600 g of a solution consisting of:
80 g of linear polyurethane resin manufactured according to DE-OS 2 423 764
130 g ter. Butanol
100 g toluene
250 g trimethylbenzene mixture (SOLVESSO 100, (from ESSO)
40 g methoxypropanol
400 g of a solution are:
27 g cellulose acetobutyrate, butyryl content 49% viscosity 20% in acetone at 20 ° C approx. 20 poises
3 g of polyether siloxane, prepared according to DE-OS 32 44 955, Example 2A
100 g methyl ethyl ketone
270 g methoxypropanol
stirred in.

The finished varnish has a very good flow and after application to leather or imitation leather under the Be conditions of Example 1 a glossy, highly elastic finish, which is particularly suitable as a final finish for furniture leather. The wet, dry and rub-through strengths are significantly improved by the addition of the mixture according to the invention to the PUR lacquer, the handle more leather-like and the appearance less plastic.

Claims (10)

1. Finishing agent for leather and imitations of leather containing solutions of cellulose acetobutyrate with a butyryl content ≧ 45% by weight, based on cellulose acetobutyrate. 2. A finishing agent according to claim 1, characterized in that the butyryl content of the cellulose acetobutyrate is 45 to 55% by weight. 3. Finishing agent according to claim 1, characterized in that the butyryl content of the cellulose acetobutyrate is 47 to 53% by weight. 4. A finishing agent according to claims 1 to 3 containing a polyether siloxane. 5. A finishing agent according to claims 1 to 4 containing a polyether siloxane, in which the polyether groups are bonded to the polysiloxane via an ether bridge or a carbamic ester group. 6. Finishing agent according to claims 1 to 5, characterized in that the polyether siloxane has at least two groups of the structure

contains, where PE is a polyether radical and R of the formula

with R ′ = alkyl, cycloalkyl, alkenyl, aralkyl, dialkylaminoalkyl, aryl or alkaryl, each with up to 10 carbon atoms
or the formula

with x = 2-25. 7. A finishing agent according to claims 1 to 6 containing a plasticizer, preferably mixtures of n-butyl stearate with phthalic diesters. 8. A finishing agent according to claims 1 to 7 containing conventional additives. 9. A process for finishing leather or imitations of leather, characterized in that finishing agents according to claims 1 to 8 are used. 10. Leather or imitations of leather finished with the finishing agents of claims 1 to 8.