阅读说明：本技术 一种皮包用耐久型抗菌柔软皮革及其制备方法 (Durable antibacterial soft leather for leather bags and preparation method thereof ) 是由 方华锋 孙军英 汪金国 汪俊凯 徐素珍 于 2020-05-20 设计创作，主要内容包括：本申请涉及天然皮革领域,提供了一种皮包用耐久型抗菌柔软皮革及其制备方法,对铬鞣整理后的真皮进行柔软、抗菌整理,通过将真皮浸渍在包含有非反应性亲水型有机硅、低分子聚乙烯乳液、疏水型柔软剂、十二烷基二甲基甜菜碱、纳米氧化锌、聚乙烯吡咯烷酮等的水溶液中,经低温干燥得到耐久型抗菌柔软皮革。通过上述方法得到的真皮具有耐久的柔软、抗菌效果。(The application relates to the field of natural leather, and provides durable antibacterial soft leather for leather bags and a preparation method thereof. The dermis obtained by the method has durable, soft and antibacterial effects.)

1. A finishing method of durable antibacterial soft leather for a leather bag is characterized in that leather after chrome tanning finishing is subjected to softening and antibacterial finishing.

2. The finishing process according to claim 1, characterized in that it comprises the following steps:

(1) preparation of functional finishing agent:

adding 5-15g/L of non-reactive hydrophilic organic silicon, 5-15g/L of low molecular weight polyethylene emulsion, 5-15g/L of hydrophobic softening agent, 10-20 g/L of dodecyl dimethyl betaine, 3-5 g/L of nano zinc oxide, 2-5g/L of polyvinylpyrrolidone, 5-8 g/L of sodium carboxymethylcellulose, 1-2g/L of dermal powder, 4-6 g/L of glycerol and 0.5-1g/L of flavoring agent into water, and uniformly stirring at a stirring speed of 200-300rpm to obtain the functional finishing agent;

the non-reactive hydrophilic organic silicon is polyester polyether hydrophilic organic silicon;

the hydrophobic softener is polydimethylsiloxane PDMS;

the molecular weight of the polyethylene in the low molecular weight polyethylene emulsion is 1000-2000;

the size of the nano zinc oxide is 30-80nm;

(2) finishing of the functional finishing agent:

and (2) soaking the leather subjected to chrome tanning finishing into the functional finishing agent prepared in the step (1), wherein the soaking temperature is 30-50 ℃, the soaking time is 3-5h, and after the soaking is finished, the leather is fished out and drained, and is dried at low temperature, so that the durable antibacterial soft leather is obtained.

3. The finishing method according to claim 2, wherein the addition amount of the dodecyl dimethyl betaine is 15g/L, and the addition amount of the nano zinc oxide is 4 g/L.

4. The finishing method according to claim 3, wherein the addition amount of the non-reactive hydrophilic silicone is 7 g/L, the addition amount of the low molecular weight polyethylene emulsion is 8g/L, and the addition amount of the hydrophobic softener is 10 g/L.

5. The finishing process according to claim 4, wherein the low molecular weight polyethylene emulsion has a molecular weight of 1500-.

6. The finishing process according to any one of claims 2 to 5, characterized in that the drying temperature of the low-temperature drying is 50 to 80 ℃.

7. The finishing process according to any one of claims 2 to 6, characterized in that the dermis is sheepskin, cowhide, pigskin, snake skin or the like.

8. The finishing method according to any one of claims 2 to 7, wherein the leather powder is obtained by grinding the leather flakes and has a particle size of 100-400 nm.

9. The finishing method according to claim 2, characterized in that the flavoring agent is rose essential oil, jasmine essential oil, green tea essential oil or microcapsule essential oil with slow release effect, preferably rose microcapsule, lavender microcapsule, jasmine microcapsule and the like.

10. A dermis obtainable by the finishing process according to any one of claims 1 to 9.

Technical Field

The application relates to the field of natural leather, in particular to a method for performing antibacterial soft surface finishing on tanned and finished leather and the prepared leather.

Background

In high-end leather products, softening finishing is one of ways to improve the additional value of leather, and a common way is to soften leather by using silane as a softening agent. Because the leather is rich in nutrients such as protein and fat, the leather is easily polluted by microorganisms during storage and use, generally, the leather is pickled by salt in the prior art, so that a large amount of pollution is caused, the hand feeling of the obtained leather is deteriorated, the surface of the leather is loose, and the luster of the leather is lost, so the leather cannot be used for processing high-grade leather, although the tannin can bring certain antimicrobial performance to the leather, the appearance of the leather is still not changed and the mechanical property of the leather is seriously reduced due to the porous structure of the fiber and the hygroscopic property of the leather during storage and use, and therefore, certain antibacterial finishing needs to be carried out on the leather surface.

For soft finishing, part of the prior art adopts silanes, for example, CN1693578A discloses a polysiloxane leather finishing material, which is prepared by compounding the following components: the component A is polysiloxane emulsion; wherein the polysiloxane has an ammonia value of 0.21-0.53 and a viscosity average molecular weight of 25000-73000; the solid content is 18-35%; the component B is polysiloxane and polyurethane copolymerization emulsion, and the solid content is 18-35%; the component A and the component B are mixed according to the weight ratio of 2: 1-5: 1. After the material is used, the leather is endowed with warm and high smooth, thick and silk-like soft hand feeling, and the leather does not migrate or volatilize and has good durability.

CN103451985A discloses an after-finishing method for improving the softness of superfine fiber synthetic leather, comprising the steps of loading 100 parts by weight of superfine fiber synthetic leather base cloth into a water kneading machine, adding 1000-1500 parts by weight of water, 5-10 parts by weight of fat-liquoring agent and 1-2 parts by weight of amphoteric surfactant, heating to 50-70 ℃, continuously rotating the water to knead for 40-60 min, controlling the water of the superfine fiber synthetic leather base cloth after the water kneading is finished, and taking out the superfine fiber synthetic leather base cloth; and drying the taken-out superfine fiber synthetic leather base cloth, then loading the dried superfine fiber synthetic leather base cloth into a rotary drum, and continuously rotating and softening for 60-120 min to finish the after-finishing of the superfine fiber synthetic leather base cloth. The method can effectively improve the softness of the superfine fiber synthetic leather, and the stress can be better dispersed when the superfine fiber synthetic leather is subjected to stress, so that the strength of the superfine fiber synthetic leather is improved to a certain extent, and the softness of the superfine fiber synthetic leather base cloth treated by the method is improved from 4mm to 6mm through the test of an XH-214 type leather softness tester.

CN110258129a discloses a preparation process of extra soft cowhide, which comprises the following process steps: step 10, preparing a semi-finished product of the cattle fiber skin; step 20, preparing oil return liquid: mixing ionic water, softening oil for softening leather, lanolin, penetrant and mildew-proof oil to prepare a return oil liquid; step 30, oil return treatment; step 40, permeating at regular time; step 50, softening treatment: placing the cattle fiber skin semi-finished product after regular permeation into a roller body of a milling device by adopting a milling device, mixing a plurality of milling balls, and rotating the roller body to mill the cattle fiber skin semi-finished product; and step 60, trimming. The bonding strength of the base cloth and the PU film in the kraft fiber leather product is improved, and the flexibility of the kraft fiber leather product is improved.

For the treatment of softness, there are processes in the prior art which employ polyurethane treatment: for example, CN109881495A discloses a water-based PU surface layer, a water-based PU double-layer leather and a manufacturing method thereof, belonging to the technical field of leather manufacturing. The water-based PU surface layer comprises the following components in parts by mass: 90-110 parts of water-based PU resin, 15-25 parts of water-based color paste and 1-3 parts of bridging agent. The water-based PU cattle second-layer leather manufactured by the invention has soft hand feeling, excellent tensile strength, tearing strength and cracking resistance, and excellent color fastness and peeling strength; after color mixing is carried out according to different color requirements, appearance patterns of the requirement are matched, the ox second-layer leather can be endowed with a better appearance decoration effect and excellent performance, and the leather is suitable for being used as high-grade leather.

CN 104479532A discloses a leather surface treating agent, which is prepared from 45-60 parts of organic silicon modified polyurethane resin, 30-45 parts of deionized water, 1-4 parts of emulsified silicone oil, 0.5-2 parts of organic silicon defoamer, 1-5 parts of polyurethane associated thickener, 0.1-0.5 part of nano TiO2 modified gelatin, 1-5 parts of superfine nano waste rubber micro powder and 0.5-3 parts of silane coupling agent. According to the invention, the superfine nano waste rubber micro powder is treated by the coupling agent and then added with the emulsion to enhance the binding force between the resin and the rubber micro powder, so that the firmness of the coating is improved; the gelatin modified by nano TiO2 is added to reduce the surface tension of the coating, improve the recoatability and improve the softness and affinity of the coating; the nanometer TiO2 modified gelatin and the nanometer waste rubber micropowder coated by the coupling agent form a coating with double nanometer layers on leather, and the coating has the characteristics of stable and durable superstrong water repellency, oil repellency and antifouling property.

In addition, there is also treatment with acrylic emulsions: for example, CN109021164A discloses a soft acrylic emulsion leather assistant and a preparation method thereof, relating to the technical field of leather assistants, wherein the leather assistant comprises the following components in parts by weight: 13001800 parts of mixed monomer, 16003000 parts of water, 2050 parts of alkali liquor, 2060 parts of emulsifier, 1030 parts of preservative, 0.110 part of initiator, 0.110 part of sodium formaldehyde sulfoxylate, 0.110 part of tert-butyl hydroperoxide and 2040 part of zinc oxide. The invention also provides a preparation method of the soft acrylic emulsion leather assistant, and the leather assistant prepared by the method has good softness and no stickiness, can improve the performances of the leather such as glossiness, gloss retention, plasticity, dry rubbing resistance, wet rubbing resistance, flexibility, water resistance and the like, and can make the processed leather feel comfortable. The preparation method of the leather assistant has stable process, can be completed in conventional equipment, reduces the investment of enterprises on production equipment, and is suitable for industrial production.

In the aspect of leather antibacterial treatment, some leather treating agents exist in the prior art, and certain antibacterial performance is given to the leather surface through the treatment of the treating agents. For example, CN110331238A discloses a leather treatment agent, which comprises the following components in percentage by weight: 25-35% of sodium polyacrylate, 1-4% of emulsifier, 1-4% of sodium tripolyphosphate, 1-4% of silver-carrying matter, 1-4% of nano titanium dioxide, 5-15% of modified rapeseed oil, 15-25% of amphoteric acrylic acid retanning agent and 25-35% of water. The invention provides a leather treating agent, which is used in textile industry, leather industry or fur product industry, realizes relatively high performances of leather such as antibacterial property, mildew resistance, compactness, dyeing depth uniformity and the like, and performances such as dye uptake, solvent resistance grade, oil resistance grade and the like, and can meet the use requirement.

CN109940938A discloses an antibacterial leather and a preparation method thereof, wherein organic silica gel is used as a main component, carboxymethyl chitosan silver is used as an antibacterial factor, modified nano silicon dioxide and modified layered double-metal oxide are used as flame retardant factors, the synergistic effect among the components, such as good combination effect of the carboxymethyl chitosan silver and a substrate, the synergistic flame retardant effect among the flame retardant factors, bonding effect between the modified nano silicon dioxide and dimethyl silicone oil, the synergistic effect between high-viscosity dimethyl silicone oil and low-viscosity dimethyl silicone oil, and the like, is utilized, and the process is improved, so that the antibacterial leather has good antibacterial and flame retardant properties, and the mechanical property and environmental protection requirements of the material are met, and the antibacterial leather can meet the performance requirements of leather materials such as bags, shoes, clothes, sports equipment, medical equipment and the like, and has a wide market prospect.

However, the above treatments are difficult to achieve both excellent hand feeling and durability, and soft finishing hand feeling may be sticky, and in addition, silver antibacterial cost is high, and additionally, antibacterial treatment is required to be performed on leather, and the process is complicated, and thus, the process is not friendly to production of high-grade leather.

Disclosure of Invention

The application aims to solve the defects in the prior art, and provides the durable soft antibacterial leather finishing method which is simple, environment-friendly, green and pollution-free.

The technical scheme of the application is as follows:

a method for finishing durable antibacterial soft leather for leather bags comprises performing soft antibacterial finishing on leather after chrome tanning. The finishing method comprises the following steps:

(1) preparation of functional finishing agent:

adding 5-15g/L of non-reactive hydrophilic organic silicon, 5-15g/L of low molecular weight polyethylene emulsion, 5-15g/L of hydrophobic softening agent, 10-20 g/L of dodecyl dimethyl betaine, 3-5 g/L of nano zinc oxide, 2-5g/L of polyvinylpyrrolidone, 5-8 g/L of sodium carboxymethylcellulose, 1-2g/L of dermal powder, 4-6 g/L of glycerol and 0.5-1g/L of flavoring agent into water, and uniformly stirring at a stirring speed of 200-300rpm to obtain the functional finishing agent;

the non-reactive hydrophilic organic silicon is polyester polyether hydrophilic organic silicon;

the hydrophobic softener is polydimethylsiloxane PDMS;

the molecular weight of the polyethylene in the low molecular weight polyethylene emulsion is 1000-2000;

the size of the nano zinc oxide is 30-80nm;

(2) finishing of the functional finishing agent:

and (2) soaking the leather subjected to chrome tanning finishing into the functional finishing agent prepared in the step (1), wherein the soaking temperature is 30-50 ℃, the soaking time is 3-5h, and after the soaking is finished, the leather is fished out and drained, and is dried at low temperature, so that the durable antibacterial soft leather is obtained.

Experimental personnel find that the hydrophilic softener component polyester polyether type hydrophilic silicone has good hydrophilicity, is soft and comfortable, is not sticky and greasy in hand feeling and has no residue on hands when being singly used for touch after being finished, but has poor smoothness although the softness is good, and the treated leather has poor durability, while a hydrophobic softener such as polydimethylsiloxane PDMS, the leather finished by the finishing agent has good softening effect and good durability, but can have sticky feeling when being touched, is easy to cause the contamination of the contact surface, can have residues on hands, the low molecular weight polyethylene can endow leather with excellent wear resistance and water resistance, but the softness is not good, experiments show that the balance between softness and durability is found through proper proportion and matched use, the softness is obtained, the durability is improved, and the technical problems that the soft finishing is sticky and the stain is generated are solved.

Preferably, the addition amount of the non-reactive hydrophilic silicone is 6-10 g/L, the addition amount of the low molecular weight polyethylene emulsion is 7-10g/L, and the addition amount of the hydrophobic softener is 8-12 g/L. More preferably, the addition amount of the non-reactive hydrophilic silicone is 7 g/L, the addition amount of the low molecular weight polyethylene emulsion is 8g/L, and the addition amount of the hydrophobic softener is 10 g/L.

The polyvinylpyrrolidone in the finishing agent can reduce the surface tension of leather, improve the permeability of the softening agent on the surface of the leather and facilitate the penetration of the softening functional components into the leather. The sodium carboxymethylcellulose can play a role in stabilization, certain bonding effect is given due to the flexibility of molecular chain segments of the sodium carboxymethylcellulose, and the glycerol has the effect of moisture absorption, so that the soft and comfortable effect on the surface of the leather can be improved.

And a certain amount of dodecyl dimethyl betaine and nano zinc oxide are added into the system, the dodecyl dimethyl betaine can play a role in resisting bacteria, permeating a stable system and the like, and meanwhile, the nano zinc oxide has a broad-spectrum antibacterial effect and can endow the leather surface with excellent antibacterial performance. Preferably, the addition amount of the dodecyl dimethyl betaine is 12-15g/L, and the addition amount of the nano zinc oxide is 3-4 g/L. More preferably, the addition amount of the dodecyl dimethyl betaine is 15g/L, and the addition amount of the nano zinc oxide is 4 g/L.

Preferably, the molecular weight of the low molecular weight polyethylene emulsion is 1500-1800.

Preferably, the drying temperature of the low-temperature drying is 50-80 ℃, because the dermis is protein, the hand feeling is easy to deteriorate and damage at higher temperature, therefore, the lower temperature is more suitable for finishing, and the finishing agent adopted by the application can realize uniform and stable adhesion on the surface of the leather at the lower temperature.

The dermis is preferably sheepskin, cowhide, pigskin, snake skin, or the like, and is not limited to the above-mentioned kind of dermis, and any other commercially available kind of dermis may be selected.

Preferably, the dermis powder is obtained by grinding crushed leather, has the particle size of 100-400nm, and can endow frosted and atomized effect to the dermis surface by finishing the dermis powder with a certain particle size on the leather surface, so that the color and luster of the leather surface are softer.

In order to further improve the added value of the leather, a flavoring agent is added into the leather, the flavoring agent can be selected from various commercially available essential oils with flavoring efficacy, such as rose essential oil, jasmine essential oil, green tea essential oil and the like, the type and the appropriate adding proportion of the essential oil can be selected according to the required flavoring effect, and the flavoring agent is not limited to the essential oils, and microcapsule essential oils with slow release effect, such as rose microcapsules, lavender microcapsules, jasmine microcapsules and the like, can also be selected.

The beneficial effect of this application lies in:

(1) the non-reactive softener composition is adopted, the preparation process is simple, the soft leather with good washing resistance and excellent antibacterial effect is obtained by compounding the composition, and the soft leather still keeps good softening effect after being washed for multiple times (more than 30 times).

(2) The softening agent can reduce the surface tension of leather, and the softening agent generates directional adsorption on the surface of the leather and forms a monomolecular film, so that the surface tension is reduced, and the surface of the leather generates soft hand feeling. Meanwhile, as the hydrophobic film formed on the surface of the fiber by the softening agent has lower surface tension and smoothness, the friction coefficient of the leather can be reduced, and the friction resistance between the leather and a human body can be reduced. The hydrophilic softener component in the components is good in hydrophilicity, soft and comfortable, no residue is left on hands after touch, but only soft effect is achieved on hand feeling, the smoothness is poor, the treatment durability is poor, the hydrophobic softener is good in softening effect and durability, but sticky feeling can be achieved when the hand touches the leather, a stained contact surface is caused, meanwhile, a low-molecular polyethylene emulsion is spread on the surface of the leather to form a film, the low-molecular polyethylene can endow the leather with excellent wear resistance and water resistance, the balance among hydrophilicity, softness and durability is found through proper proportion, the durability is improved while the softness is obtained, the technical problem that stickiness can occur during soft finishing is solved, and the antibacterial component is added to endow the leather with excellent and durable antibacterial performance.

(3) The leather finishing process is simple, high-temperature reaction is not needed, the damage of high temperature to leather is reduced, the processed leather has excellent washing resistance, the working procedures are saved, meanwhile, the soft and antibacterial processing is realized, and the leather finishing process is environment-friendly.

Detailed Description

The invention is further described below by means of specific embodiments. The examples are described only for the purpose of facilitating understanding and application of the invention and are not intended to limit the scope of the invention.