SU1348373A1 - Method of finishing natural skins - Google Patents

Abstract

The invention relates to the leather industry and allows improving the quality of the coating and simplifying the process. The skins are trimmed using a non-pigmented primer and top coat paint, with each layer using aqueous emulsion of methyl acrylate copolymer, butyl acrylate and methacrylate acid with a content of carboxyl groups of 8-15%, stabilized by an ammonia zinc complex as a polymer film former. salt. Non-pigmented soil contains, wt%: aqueous emulsion of a copolymer of methyl acrylate, butyl acrylate and methacrylic acid with a carboxyl group content of 8-10% (calculated on the dry matter) 11.5-l6.5j ammonia complex of zinc salt (calculated on the dry substance) O - -0.8; water the rest. The coating paint contains, in wt.%: A pigment concentrate of 4.5-6.5 j aqueous emulsion of a copolymer of methyl acrylate, butyl acrylate and methacrylic acid with a carboxyl group content of 10-15% (calculated on the dry matter) 19.5-30.5 , ammonia complex of zinc salt (on a dry basis) 0.9-1.9; water the rest, 2 z. p. f-ly. 1 tab. S (L with 4 SHE SO OO

Description

11348373

refers to leather tanning

production and can be used in the finishing of leather for uppers.

The aim of the invention is to improve the quality of coatings and simplify the process.

The essence of the invention lies in the fact that, according to the method of finishing natural leather, non-pigmented soil and top coat paint use aqueous emulsion of methyl acrylate, butyl acrylate and methacrylic acid copolymer with a content of carboxyl groups of 8-15%, stabilized by an ammonia complex of zinc salt as a polymer film-forming agent.

The emulsion synthesis of the indicated copolymer is carried out by the method of emulsion polymerization. The duration of the dosage of the monomer mixture with the emulsifier (C-10) is 2-2,5 at 78-85 ° C. The initiator (ammonium persulphate) was charged as the monomer mixture was drained in three steps: at the beginning, after the half of the monomer mixture was drained, and after the dosage of the monomers was finished. After the introduction of the last portion of the initiator, hold for 30-40 minutes. The ratio of monomers in the copolymer is respectively (59-64) :( 26-28): (8-15).

A stabilizing additive (ammonia complex of zinc salt) is introduced into the finished emulsion during the preparation of the coating compositions.

This emulsion is characterized by the following colloid-chemical and physico-mechanical properties: Content of mass fraction of dry matter,% 40 ± 3 Content of carboxyl groups,% 8-15 pH6 ± 1 Surface tension, mN / m 35 ± 3 Resistance to ammonia and

Electrolytes Resistant

Strength of films at stretching, MPa

3t2

Relative elongation of films at break,%

700 ± 200

Example 1. On a semi-finished chrome tanning with a natural front surface from raw material HJJOBK; A light, gray color, developed according to a standard technique, applied non-pigmented soil of the following composition, wt.%:

Aqueous emulsion of a copolymer of methyl acrylate, butyl acrylate and methacrylic acid with a carboxyl content of 5 groups of 8 (in terms of. Dry quantity) 11.5

Ammonia complex of zinc salt 0 (and in terms of

dry bore (quality) 0,2 Voda88,3

After drying the coating at 33–1 ± 5 ° C for 25 ± 5 min, a skin coating of the following composition was applied on the skin, wt.%:

Pigment concentrate (in terms of dry substance) 4,5 Aqueous emulsion of a copolymer of methyl acrylate, butyl acrylate and methacrylic acid with a carboxyl group content of 10% (based on dry substance) 19.5 Ammonia complex of zinc salt

(in terms of dry substance) 0.9 Water75.1

Next, the skin is dried under the same 5 conditions and pressed on a hydraulic press at a plate temperature of 13 ± 1 MPa. Then, the skin is applied 2-4 times on the MAL unit with a coating paint of the indicated composition with intermediate drying for 2.5 ± 0.5 min and then the skin is pressed at 75 ± 5 ° C and pressure of 5,010, 5 MPa. PRI mme R 2. Chrome tanned leather with a polished face of brown color from raw material was light, developed according to a typical procedure, as in Example 1, a layer of non-pigmented soil was applied following the composition, in wt.%:

0

five

0

0

five

31

Methyl acrylate copolymer aqueous emulsion,

butnlacrylate and metacrylonic acid with a carboxyl group content of 10% (calculated on the dry matter) 16.5 Ammonia complex of zinc salt

(in terms of dry substance) 0.8 Water 82.7 Apply a coat of coating paint of the following composition, wt%: Pigment concentrate (based on dry substance) 6.5 Aqueous emulsion of methyl acrylate copolymer, polycarbonate and methacrylate acids with a carboxyl group content of 15% (calculated on the dry matter) 30.5 Ammonia complex of zinc salt

(in terms of

dry matter) 1,9 Water 61,1

PRI me R 3. A chrome-plated leather with a natural beige-colored face from raw materials produced a goby made according to standard methods, as in Example 1, a layer of depigmented soil of the following composition, in wt.%:

Aqueous emulsion of a copolymer of methyl acrylate, butyl acrylate and methacrylic acid with a carboxyl group content of 9% (based on solid) 14.0

Ammonium complex of zinc salt

(in terms of dry substance) 0.5 Water 85.5 As a coating paint, the following composition is used, wt.%: Pigment concentrate (in terms of dry substance) 5.5 Aqueous emulsion of methyl acrylate copolymep.

483734

butyl acrylate and metacryloic acid with a carboxyl group content of 12% (calculated on the dry matter) of 25.0

Ammonia complex

zinc salt

(in terms of

dry matter) 1,5

Water68.0

Physico-mechanical properties of the coatings are shown in the table.

ten

The use of the proposed finishing method reduces the labor intensity in the preparation of coating compositions by reducing their number, and also shortens the technological cycle of leather finishing by eliminating the consolidation process, allows to obtain coatings with high physicomechanical properties (adhesion, light fastness, resistance to repeated bending and wet friction).

Claims (3)

Invention Formula 1, The method of finishing natural leathers by successively applying layers of non-pigmented soil based on an aqueous emulsion of a polymer film former and a top coat based on an aqueous emulsion of a polymer film former and a pigment concentrate, in order to improve the quality of coatings and simplify the method As a polymer film former in each layer, an aqueous emulsion of a copolymer of methyl acrylate, butyl acrylate and methacrylate acid is used with a carboxyl group content of 8–15% stabilized ammonia complex of zinc salt. 0 2. The method according to claim 1, characterized in that the layer of non-pigmented soil has the following composition, in wt.%: Methyl acrylate copolymer aqueous emulsion, butyl acrylate and metacryloic acid with a carboxyl group content of 8–10% 11.5–16.5 (calculated on the dry matter) 51348373 Ammonium complex of zinc salt (in terms of dry substance) 0.2-0.8 Water Else 3. The way pop. 3, I differ, and with the fact that the layer of asky has the following composition, wt.%: Q Pigment concentrate 4.5-6.5 Resistance to bending multiple cycles Coating resistance to wet friction, turns Adhesion, N / m in a dry state in a wet state Frost resistance -15 C, points St resistance after irradiation under the lamp Editor M. Tsitkina Compiled by E. Bobkoia Tehred L. Oliynyk Order 5164/25 Circulation 373Subscription VNIIPI USSR State Committee for Inventions and Discoveries 4/5, Moscow, Zh-35, Raushsk nab. 113035 Production and printing company, Uzhgorod, Projecto st., 4 butyl acrylate and methacrylic acid with a carboxyl group content of 10–15% (calculated on the dry matter) Ammonia complex zinc salt (in terms of 5000 500 550 370 35,000 500 480 360 10,000 220 320 180 Proofreader L. Pilipenko