CS267015B1 - Method of tanned leathers production with decorative pattern's pronounced image drawing - Google Patents

Abstract

The solution concerns an industrial area manufacture of leather with ornamental design. The purpose is to achieve sharp contrasts between nubuck sanded ornamental facets tread pattern and shiny pads facets of leather. This purpose is achieved by getting on precisely groomed and washed leather is treated with pyrophosphate sodium at 0.1 to 7.0% at temperature 25 to 35 ° C, further anionic dyeing to leather in an amount of 0.2 up to 3.5% at 25 to 55 ° C; with a mixture of sulfated and sulfated lubricants in the amount of 4 to 8% and fill synthetic tanning compounds based on sulfonated of phenolic condensates; with resins at 4-8 ° C temperature for 60 to 230 minutes, as follows pre-treated leather fixes lower with a fatty acid in an amount of 0.5 to 2.0% for 20 to 30 min. at temperature 25 to 55 ° C, then embossed ornamental tread pattern at 80 to 90 ° C pressure min. 30 MPa and a delay of 2 to 5 seconds it is further sanded with grit paper 240 to 400, brushed off and put on the leather as follows the treated face is sprayed with a hydrophobic varnish.

Description

The invention relates to a method of pretreatment and surface treatment of special nubuck leathers, wherein the leathers are neutralized, dyed, liqueured, filled, fixed, left to rest, squeezed, embossed, dried, moistened, softer, resp. they stretch, further soften and cut, then surface treatment by spraying with paint and gloss, patterning, grinding with dusting and spraying.

The pretreatment and surface treatment of nubuck leathers is still carried out in a manner leading to special patterned nubuck leathers, according to which the tanned leathers are washed, then usually neutralized in a separate bath, then liquefied and fixed in another bath. The pre-treated leather is fixed and left to rest. They are dried from the wet to the dry state and softened as required. The leathers are further patterned and their face is sanded. The dismantled and abraded leathers are soaked again, dyed in a bath, liquefied and fixed again. The leathers are washed and, after dripping, are again changed from wet to dry by drying. They are allowed to lie down, moistened, softer by pounding in a barrel, stretched and, if necessary, the nubuck face is adjusted by brushing.

In this method, the pretreatment of the leather is carried out in two separate phases, i.e. neutralization, liquefaction, fixation, soaking, dyeing, librating, fixation, separated from each other by drying, patterning and grinding. The individual pretreatment operations are carried out again in a bath at a temperature of 35 to 60 [deg.] C. for a period of 3 to 7 hours, the leather also not being dyed. In this way, nubuck leathers with a smooth drawing of the face are obtained, which do not usually have the required highlighted pictorial drawing of the tread, or also no combination of nubuck finish with glossy surfaces of a smooth uncut face.

The method according to the invention eliminates the above-described disadvantages of the hitherto known methods of pretreatment and treatment of nubuck leathers. The essence of the invention lies in the fact that the tanned leathers are precisely ground to the required thickness, after washing they are neutralized with sodium pyrophosphate according to CS-240 122, further dyed, liquefied, filled and pretreated, fixed and washed and left to rest. After being converted to a dry state, the pretreated hides in the pretreated manner are treated according to the invention by first spraying with paint and gloss, then patterning, sanding with dusting and cutting with a protective varnish.

According to the invention, the above-described disadvantages are eliminated by first treating the tanned, precisely coated and washed leather with sodium pyrophosphate in an amount of 0.1 to 7.0%, based on the weighted weight, as a neutralizing agent at a bath temperature of 25 to 55 ° C. , are liquefied with a mixture of sulfated and sulfitated lubricants in an amount of 4 to 8%, all based on the weighted weight of the leather, at a bath temperature of 25 to 55 ° C for 60 to 230 minutes. Dyed and pretreated leathers are fixed with a lower fatty acid in an amount of 0.5 to 2.0% for 20 to 30 minutes. at a temperature of 25 to 55 ° C.

Furthermore, the process according to the invention is carried out by washing the leather, letting it rest, machining it by squeezing and embossing and converting it from the wet to the dry state by drying. After softening and trimming, the crusted leather is treated to achieve the desired effect according to the invention by first spraying with a colored water spray composed of tinted casein paint in an amount of 8 to 12 parts by weight, an acrylate dispersion of 12 to 20 parts by weight, an emulsion polymer varnish containing an acrylate polymer with a filling effect of 10 to 15 parts by weight and a wax dispersion of 2 to 5 parts by weight, supplemented with water up to 100 parts by weight. After drying, the leather is sprayed with a gloss with fixing effects based on an aqueous dispersion of softened nitrocellulose. The leather is then extruded ornamental

CS 267 015 Bl pattern at a temperature of 80 to 90 ° C, a pressure of at least 30 MPa and a delay of 2 to 5 seconds. This pattern is sanded with special sandpaper and the leather is dusted. The leathers thus prepared are sprayed with a hydrophobic solvent spray in an amount of 6 to 10 parts by weight or in a mixture with nitrocellulose varnish 0 to 14 parts by weight, supplemented with a suitable solvent per 100 parts by weight.

According to the above-mentioned procedure, when consuming finishing solutions of 15-25 g / 10 dm of colored spray, 5 to 8 g / 10 dm ^of gloss and 8 to 15 g / 10 sod of water-repellent spray, a surface treatment of special nubuck leathers with marked higher effects according to the invention is performed.

The technical effect of the method according to the invention consists in achieving on the one hand an enhanced two-color pictorial drawing of the tread, and on the other hand a combination of a nubuck treatment with a smooth surface treatment in the form of glossy surfaces of an uncut face between the tread pattern.

The main conditions for achieving these new effects are the following:

a / Precise trimming over the entire surface of the leather to the required thickness within a tolerance of - 0.1 mm.

b) Uniform coloring of the leather achieved by the use of sodium pyrophosphate in an amount of 0.1 to 7.0%, depending on the properties of the dye used, in particular its coloring ability.

c / Filling with synthetic tanning agent based on phenolic condensates, or resin in an amount of 4 to 8%, depending in particular on the type of leather used.

d / Uniform design in the entire surface of the leather with a perfectly adjusted ironing machine, ie uniform application of temperature and pressure in the entire surface of the pattern plate, under conditions of temperature 80 to 90 ° C, pressure min. 30 MPa and delays of 2 to 5 seconds, thus creating shaped surfaces on the leather surface with unequal embossing depths.

e / Grinding of the upper surfaces of the molding with a perfectly adjusted grinding machine using fine sandpaper with a grain size of 240 to 400, thus achieving a special combination of nubuck and smooth surface of the molding of the face.

f / A special arrangement of the sequence of surface treatment operations consisting in that the leathers are first sprayed with paint and protective gloss, then they are patterned and sanded with dust and finally sprayed with protective varnish.

Said conditions for achieving the described technical effect according to the invention are essential for the leather with the highlighted pictorial drawing to be characterized by the desired two-color effect of a certain shade, as well as a combination of nubuck and glossy smooth surfaces of the molding. In addition, the leather retains the processing durability of the tread.

The process according to the invention is further elucidated by the following examples.

Example 1

Tanned cowhides are precisely ground to a thickness of, for example, 3.2 - 3.4 mm measured twice. After being placed in a tannery, they are washed with water at 35 ° C for 15 minutes. Then, a solution containing together neutralizing, lubricating, filling and coloring preparations is prepared separately according to the method according to AO No. 24032, namely:

Water 35 ° C 30%

Mixture of sulphated and sulphited lubricants 6 Ϊ

CS 267 015 Bl

Synthetic tanning based on sulfonated phenolytic condensates 8%

Powdered dye 1.2%

The solution is prepared in a separate vessel by diluting the lubricants and synthetic tan in 30% water at 35 ° C. Separately, prepare a solution of the dye in 5% water at 35 ° C, add to the lubricant and tan solution, and mix.

200% of water at 35 ° C and 4% of sodium pyrophosphate are added to the washed leather in a tanning vessel. The container is closed and started. A separately prepared solution of a mixture of lubricants, tannins and dyes is filled with the hollow axis. Barrel movement time 60 min. During this operation, the pH of the bath is as follows:

after 5 minutes of running 7.8 to 8.0 • after 60 minutes of running 6.5 to 6.7

At the end of the operation, the hides in the bath are fixed by adding a lower fatty acid, eg formic acid (1: 1θ) in an amount of 1.4% for 30 minutes. The leather is then washed with water at 25 ° C for 15 minutes. The leather is thrown out of the tannery and left to rest.

The next sequence of operations is this:

Squeezing

Ejection

Drying according to the operating conditions of the manufacturer

Moisture

Whistling

Tension

Trimming

The surface treatment is then carried out thus: Paint spraying a / Composition of spray Tinted casein paint 10 parts by weight Acrylate dispersion 17 Emulsion acrylate polymer varnish 13 Wax dispersion 3 <i « Water 57 2 b / Spray consumption 20 g / 10 dm Gloss spray a / Composition of spray Aqueous dispersion of softened nitrocellulose 80 to 94 parts by weight Fixing agent 5 to 19 ” Silicone product J «» H b / Spray consumption 7 g / 10 dm ²

Design

Temperature 80 to 90 ° C, pressure min 30 MPa, delay 2-4 s

Sanding I x paper AVUKO grit 320

Dusting

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Grinding II

Finishing with AVUKO paper grit 320

Dusting

Hydrophobic paint spraying a / Spray composition

Water repellent 8 parts by weight

Solvent 88

Nitrocellulose varnish 4 b / Spray consumption 12 g / 10 dm

Drying

Example 2

Tanned cows are precisely ground to a thickness of, for example, 3.2-3.4 mm, measured twice, after being placed in a tannery vessel, washed with water at 35 ° C for 15 minutes and prepared for pre-treatment, which is carried out as follows:

Neutralization Water 35 ° C 200%

Sodium pyrophosphate 4% movement 60 min Wash Water 55 ° C 200%

Dye 3.5% movement 45 min

Lubrication mixture of sulfated and sulfitated lubricants 6% movement 45 min Filling of synthetic tannin based on sulfonated and phenolic condensates 4% resin 2% movement 60 min Fixation of formic acid 1:10. 1.8% movement 30 min Wash water 25 ° C movement 20 min The leather is thrown out of the tin container and left to rest. The next sequence of operations until the completion of the finished state is the same as in Example 1. Example 3

Tanned cowhides are precisely ground to a thickness of, for example, 3.2-3.4 mm, measured twice. After throwing into the tannery, wash with warm water for 15 minutes. The leathers thus prepared are pretreated according to the procedure of Example I or 2. The leathers are thrown out of the tin container and left to rest. The next sequence of squeezing, stamping, drying, moistening, softening, stretching, trimming operations is the same as in Example 1.

In the surface treatment, the procedure is as follows:

Paint spraying

It is carried out according to the procedure of Example 1.

CS 267 015 Bl

Gloss spraying 'a / Spray composition'

Aqueous dispersion of softened nitrocellulose 80 to 95 parts by weight Fixing agent 5 to 20 "b / Spray consumption 7 g / 10 dm ² Spraying with decorative varnish / Spray composition Nitrocellulose varnish 50 parts by weight

Organic solvent 47

Bead pigment color 3 b / Spray consumption 2 8-15 g / 10 dm Patterning, grinding I, dusting, grinding II, dusting and spraying with a hydrophobic varnish are carried out according to Example 1.

Claims (2)

OBJECT OF THE INVENTION 1. A process for the production of tanned leathers with an accentuated pictorial drawing of an ornamental design and a combination of nubuck treatment with glossy surfaces of a smooth uncut face, characterized in that precisely coated and washed leathers are treated with sodium pyrophosphate in an amount of 0.1 to 7.0% at 25 to 35 ° C, further dyed with anionic dyes on leather in the amount of 0.2 to 3.5% at a temperature of 25 to 55 ° C, liqueur with a mixture of sulfated and sulfitated lubricants in the amount of 4 to 8% and filled with synthetic tanning agents based on sulfonated phenolic condensates, or resins in an amount of 4 to 8 ° C at a temperature for 60 to 230 minutes, the pretreated leather is fixed with a lower fatty acid in an amount of 0.5 to 2.0% for 20 to 30 minutes. at a temperature of 25 to 55 ° C, then they are patterned with a decorative pattern at a temperature of 80 to 90 ° C, a pressure of min. 30 MPa and a delay of 2 to 5 s, it is then sanded with sandpaper with a grain size of 240 to 400, dusted and sprayed on the leather with the face thus treated with a hydrophobic varnish. 2. The method according to item 1, characterized in that the color treatment is spray-applied in the composition of tinted casein paint of 8 to 12 parts by weight, acrylate dispersion of 12 to 20 parts by weight, emulsion polymer lacquer containing acrylate polymer with a filling effect of 10 to 15 parts by weight. parts and wax dispersion 2 to 5 parts by weight, supplemented with water per 100 parts by weight, at a spray consumption of 15 to 25 g / 10 dm, after drying the leather is sprayed with a gloss with a fixing effect based on an aqueous dispersion of softened nitrocellulose at a spray consumption of 5 to 5 parts. 8 g / 10 dm, after dismantling and sanding, the leathers are sprayed with a hydrophobic solvent spray, or in a mixture with nitro2 cellulose varnish at a spray consumption of 8 to 15 g / 10 dm.