A method of cleaning oil-finished leather

Abstract

The application discloses a method for cleaning oil and cream leather, which comprises the following operation steps: S1, two-step wiping of oil and cream, 1) first-step wiping of oil and cream, the leather is wiped by oil and cream wiping liquid and then dried; 2) second-step wiping of oil and cream, the leather is wiped by oil and cream wiping liquid and then dried; S2, surface treatment of the leather, the surface of the leather after the wiping and drying in S1 is treated by oil and cream inhibiting liquid, and the surface is cleaned after standing, and then the leather is dried and finished. The method for cleaning oil and cream leather can effectively treat the oil and cream problem on the surface of the leather, and the wear and softness of the leather are considered.

Description

Technical Field

[0001] This invention relates to fine polymer materials, specifically to a method for cleaning oily leather. This method is mainly applied to the impregnation process of microfiber synthetic leather, and is particularly suitable for the later alkali reduction fiber opening process. Background Technology

[0002] The production of genuine leather from animal hides inevitably involves triglycerides. Some are present in the animal hide itself, while others are not completely removed during tanning. Still others are added as fatliquoring agents to soften the leather. Since triglycerides and their hydrolyzed fatty acids can crystallize at room temperature, especially in environments with high relative humidity and temperatures of 10-15°C (early winter and early spring), these crystals form a white bloom on the surface of leather products such as clothing, shoes, bags, and car interiors. This bloom detracts from the sensory and performance of the leather. Since the 1980s, when fatliquoring agents were heavily added during the production of soft leather, this bloom has occurred almost annually, becoming an unavoidable product quality problem in the leather industry.

[0003] Whether it's leather in the manufacturing workshop or leather products, once oil bloom appears, it's difficult to completely eliminate it with simple wiping. It will regenerate in as little as 2-3 days, or as long as 5-6 days, and this cycle can continue indefinitely. Oil bloom on semi-finished products in tanneries can be completely resolved by washing with water and then adding fat. However, this method not only increases costs but also causes irreversible changes in product quality. Therefore, preventing oil bloom has always been one of the most important tasks in the leather industry.

[0004] The formation of oil cream originates from the quantity and purity of lipids per unit area, with a crystal particle size ≥ 0.1 mm. The oil cream consists of fatty acids, low-iodine triglycerides, and neutral salts. Studies have shown that fatty acid crystals in leather originate from the migration of fatty acids from within the leather to the leather surface. More significantly, triglycerides are hydrolyzed into fatty acids by enzymes and then migrate to the leather surface, resulting in regeneration even after wiping. To further verify that tallow is the source of leather exudates, we performed infrared analysis on the fatty acid components of the leather exudates, finding that the main components are C16 and C18 fatty acids. Mass spectrometry analysis showed a peak of 255.2 for C16 palmitic acid and a peak of 283.3 for C18 stearic acid. (See attached analysis). Figure 1 .

[0005] In summary, the problem of oil bloom that occurs during the preparation of genuine leather in the existing technology needs to be addressed. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a method for cleaning leather oil cream.

[0007] A method for removing leather oil cream includes the following steps: S1 Two-Step Oil Removal Cream 1) First step: Remove the oil cream The leather is wiped with an oil-based polishing solution and then dried. 2) Second step of wiping off the oil cream The leather is wiped with an oil-based polishing solution and then dried. S2 Leather Surface Treatment After the leather surface has been wiped and dried with S1 oil cream, it is surface treated with oil cream inhibitor, left to stand, cleaned, dried, and then coated.

[0008] As a further improvement to this solution, the oil cream wiping liquid is a polysaccharide solution.

[0009] As a further improvement to this solution, the oil-based wiping liquid is composed of the following components in parts by weight: 5-10 parts polysaccharide; The remainder is water; Among them, polysaccharides are any one or more of soluble starch, carboxymethyl cellulose, and gelatinized edible starch.

[0010] As a further improvement to this solution, the temperature of the first oil-based wiping liquid is 40-45℃.

[0011] As a further improvement to this solution, the second oil cream wiping liquid is a fatty acid solution.

[0012] As a further improvement to this solution, the oil-based wiping liquid comprises the following components in parts by weight: 10-15 parts of fatty acid solvent; The remainder is water.

[0013] As a further improvement to this solution, the oil-curing liquid comprises the following components in parts by weight: Salicylic acid 5-10 parts; 1.5 to 2 parts glucose; 0.5 to 1 part xylose; 0.5 to 1 part mannose; Galactose 1 to 1.5 parts; The remainder is water.

[0014] As a further improvement to this solution, the temperature of the oil-blooming inhibitor is 40~45℃.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1) This method uses cotton fiber towels as a carrier, which is simple to operate and uses inexpensive materials.

[0016] 2) All materials used avoid toxic chemical reagents as much as possible, which is beneficial to the car interior.

[0017] 2) Polysaccharides are used to remove some of the neutral salts during the process to prevent crystal nuclei from forming.

[0018] 3) Use complex natural monosaccharide materials to appropriately inhibit the hydrolysis of new fats. Attached Figure Description

[0019] Figure 1 Mass spectra of fatty acids C16 and C18, the main components of the oil cream; Figure 2 In Example 1, the leather is shown in a display image after 4 months; Figure 3 Example 2, leather display image after 4 months; Figure 4 Example 3, leather display image after 4 months; Figure 5 Comparative Example 1, leather display image after 4 months; Figure 6 Comparative Example 2, leather display image after 4 months; Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to embodiments: Prepare three polysaccharide solutions with a mass fraction of 5% and a temperature of 40-45℃: ① Water + soluble starch. ② Water + carboxymethyl cellulose. ③ Water + gelatinized edible starch.

[0021] Three fatty acid solvent solutions with a mass fraction of 10%~15% and a temperature of 30~35℃: ④ Water + ethylene glycol methyl ether + ethylene glycol butyl ether. ⑤ Water + ethylene glycol methyl ether + phenyl cellosolve. ⑥ Water + ethylene glycol butyl ether + phenyl cellosolve.

[0022] Two oil bloom suppression solutions: ⑦ Water + 5% salicylic acid + 1.5 mol glucose, 0.5 mol xylose, 0.5 mol mannose, 1 mol galactose. ⑧ Water + 5% salicylic acid + 2 mol glucose, 1 mol xylose, 1 mol mannose, 1.5 mol galactose.

[0023] A polysaccharide solution with a mass fraction of 10% and a temperature of 40-45℃: ⑨ Water + soluble starch.

[0024] Example 1 Take a piece of leather with oil bloom and divide it into three areas (1, 2, and 3). Use a cotton towel to absorb the polysaccharide solutions ①, ②, and ③ respectively, then wipe the oil bloom off the leather surface. Wipe dry with a clean towel. Next, use a clean towel to absorb the fatty acid solvent solution ④ to remove the oil bloom from the leather surface. Continue to wipe dry with a clean towel, then use a clean towel to absorb the oil bloom inhibitor solution ⑦, applying 100-150 g / m². 2 Apply the oil to the leather surface and let it sit for 10-15 minutes. Finally, wipe the surface with a damp towel. Observe the oil bloom after 4 months: no oil bloom should be observed.

[0025] Example 2 Take a piece of leather with oil stains and divide it into 4 or 5 sections. Use a cotton towel to absorb solution ① (polysaccharide solution) and wipe the oil stains off the leather surface. Then wipe it dry with a clean towel. Next, use clean towels to absorb solutions ⑤ and ⑥ (fatty acid solvent solutions) to remove the oil stains from the leather surface. Continue to wipe the leather surface dry with a clean towel, then use a clean towel to absorb solution ⑦ (oil stain inhibitor solution), applying 100-150 g / m². 2 Apply the oil to the leather surface and let it sit for 10-15 minutes. Finally, wipe the surface with a damp towel. Observe the oil bloom after 4 months: no oil bloom should be observed.

[0026] Example 3 Take a piece of leather with oil stains and divide it into 6 and 7 sections. Use a cotton fiber towel to absorb the solutions of mass fractions ① and ⑨ (polysaccharide) and wipe the oil stains off the leather surface, then wipe it dry with a clean towel. Next, use a clean towel to absorb the fatty acid solvent solution ④ and wipe away the oil stains. Continue to wipe the leather surface dry with a clean towel, then use a clean towel to absorb the oil stain inhibitor solution ⑧, applying 100-150 g / m². 2 Apply the oil to the leather surface and let it sit for 10-15 minutes. Finally, wipe the surface with a damp towel. Observe the oil bloom after 4 months: no oil bloom should be observed.

[0027] Comparative Example 1 The difference from Example 1 is that step S1 (2) is omitted, that is, the leather is not treated with fatty acid solvent solution.

[0028] After standing for 4 months, observe the condition of the oil and frost: oil and frost appeared.

[0029] Comparative Example 2 The difference from Example 1 is that step S2 is omitted, that is, the surface of the un-leathered surface is treated with oil cream inhibitor.

[0030] After standing for 4 months, observe the condition of the oil and frost: oil and frost appeared.

[0031] The performance tests of the leathers obtained in Examples 1-3 and Comparative Examples 1-2 according to automotive leather standards are shown in the table below. The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent modifications made using the present invention are within the patent protection scope of the present invention.

Claims

1. A method of cleaning oil-finished leather, characterized in that, The following steps are included: S1 Two-Step Oil Removal Cream 1) First step: Remove the oil cream The leather is wiped with an oil-based polishing solution and then dried. 2) Step 2: Remove the oil cream The leather is wiped with an oil-based polishing solution and then dried. S2 Leather Surface Treatment The surface of the leather which has been wiped and dried by S1 oil cream is inhibited by oil cream in accordance with 100~150g / m 2 The surface of the leather is treated by the amount of wiping, and the surface is cleaned after standing for 10~15min, and then dried and finished. The oil-based wiping liquid is a polysaccharide solution; The oil-based wiping liquid is composed of the following components in parts by weight: 5-10 parts polysaccharide; The remainder is water; Among them, polysaccharides are any one of soluble starch, carboxymethyl cellulose, and gelatinized edible starch; The temperature of the oil-based wiping liquid is 40~45℃; The second oil-based wiping liquid is a fatty acid solvent solution; The temperature of the fatty acid solvent solution is 30–35°C; The oil-based wiping liquid comprises the following components in parts by weight: 10-15 parts of fatty acid solvent; The fatty acid solvent is any two of ethylene glycol methyl ether, ethylene glycol butyl ether, and phenyl cellosolve; The remainder is water; The oil-curing inhibitor comprises the following components in parts by weight: Salicylic acid 5-10 parts; 1.5 to 2 parts glucose; 0.5 to 1 part xylose; 0.5 to 1 part mannose; Galactose 1 to 1.5 parts; The remainder is water; The temperature of the oil-blotting inhibitor is 40~45℃.

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