CN106832878B - A kind of dyed polyurethane resin and its application in synthetic leather - Google Patents

Abstract

The invention discloses a dyed polyurethane resin and its application in preparing synthetic leather. In parts by weight, 0.01-10 parts of prodigiosin; 5-70 parts of polyurethane resin; 20-94.9 parts of organic solvent; 0-10 parts of auxiliary agent. In the present invention, prodigiosin is used as a coloring agent, and polyurethane resin is dissolved in an organic solvent (such as dimethylformamide, ethanol, acetone or ethyl acetate, etc.) to make a slurry. The suitable composition and preparation method make Prodigiosin can be uniformly dispersed and fully dissolved, so as to maintain the stable performance of PU color paste; the application process of PU color paste is simple and easy to operate, and the color PU leather obtained is bright in color when it is used in the wet process of synthetic leather or in the finishing process , Good mechanical properties, good fastness to wet treatment, excellent antibacterial effect.

Description

A kind of dyed polyurethane resin and its application in synthetic leather

technical field

The invention relates to the technical field of synthetic leather processing, in particular to an environment-friendly, antibacterial, mildew-resistant and dyed polyurethane resin and its application in the preparation of synthetic leather.

Background technique

Polyurethane (PU) synthetic leather has excellent properties such as outstanding wear resistance, strength and toughness, solvent resistance, oil resistance, and high cutting rate, and is widely used in sports and leisure shoes, leather shoes, leather clothes, bags, sofas, stationery, It is an ideal substitute for natural leather in products such as automotive interiors.

However, ordinary polyurethane synthetic leather is not long after it is made into a finished product. Because the material contains nutrients necessary for bacteria and mold, under suitable temperature and humidity conditions, microorganisms will multiply in large numbers, causing the biodegradation of polyurethane, resulting in mildew on the leather surface. Changes, cracks, shorten the service life of synthetic leather, and even lose its value because it cannot be used.

At present, most PU synthetic leathers are oil-soluble systems, and organic solvents such as 2-butanone, dimethylformamide, acetone, and ethyl acetate are mostly used as application media. However, synthetic leather cracks in a short period of time, mostly due to the decomposition of the metabolites of esterases secreted by microorganisms. For antibacterial and antifungal synthetic leather, some leather antimold treatments are carried out by removing nutrients, controlling environmental conditions or radiation antifungal, fumigation and using antifungal agents. However, these methods undoubtedly put forward strict requirements on the environment and operating conditions and processes. For example, the method of using ethylene oxide to penetrate the interior of the leather to sterilize requires high safety protection measures. The process conditions are complicated, the cost is high, and serious Pollution of the environment; radiation anti-mildew law requires the construction of sites in sparsely populated areas, and the cost is high. Some PU leather uses nano-metal materials (such as nano-silver, etc.), natural antibacterial agents (such as chitosan, etc.), organic antibacterial agents (such as quaternary ammonium salts, etc.) . As for colored PU synthetic leather, at present, most of them use heterogeneous coloring, and use acid dyes, metal complex dyes, neutral dyes, disperse dyes or pigments for coloring treatment through the action of additives.

This kind of colored synthetic leather material with antibacterial and antifungal effects needs to add various additives in the dyeing bath due to the compatibility of the coloring agent and antibacterial and antifungal treatment agent with the polyurethane solution during processing, resulting in sewage treatment. It is more difficult to discharge, and at the same time, because it belongs to the mixing of heterogeneous systems, it also causes aggravation of the cracking phenomenon.

The invention adopts the green and environment-friendly biological dye prodigiosin to solve the above problems, and obtains a synthetic leather product with excellent physical and mechanical properties, good wet treatment fastness, and good antibacterial and antimildew effects.

The prodigiosin used in the present invention is a natural red pigment fermented by biological bacteria, which belongs to fat-soluble dyes and is soluble in organic solvents such as ethanol, acetone, dimethylformamide, ethyl acetate and tetrahydrofuran. Prodigiosin is a biologically active natural pigment produced by a variety of microorganisms. It contains 3 pyrrole rings and its structural formula is:

Prodigiosin has the advantages of anti-malarial, anti-bacterial, fungal biological activity and autoimmune suppression activity. The in vitro antibacterial test shows that prodigiosin has the effect on Staphylococcus aureus (penicillin-resistant, erythromycin-resistant strains) and flexneri. Helicobacter has a good inhibitory effect. Moreover, it overcomes the seasonal and regional limitations of extracting pigments from plants, and can be mass-produced to meet people's needs.

Prodigiosin has good stability in acidic or neutral environment (pH 3.0-7.0), and can remain stable for a long time. The pigment is unstable under alkaline conditions, and the color gradually changes with the increase of pH value. Lighten until it becomes colorless. Another study shows that the content loss of prodigiosin is relatively small below 40°C; 80% of the color value is still retained at 100°C for 1 hour. According to the naked eye, the color of prodigiosin is almost unchanged, which shows that prodigiosin It has good thermal stability and has low temperature requirements during processing, so it can be applied to thermally processed products.

At present, there have been many reports on the application of prodigiosin as a colorant in the printing and dyeing process. Most of them use organic solvents to dissolve prodigiosin and then dye or print fibers with the help of some auxiliary agents. The application process is the same as The application process of disperse dyes is relatively similar and belongs to heterogeneous treatment. However, the application of prodigiosin as a fat-soluble coloring agent in synthetic leather technology has not been reported yet.

Contents of the invention

The invention provides an environment-friendly, antibacterial, antifungal, and antifungal stained polyurethane resin. Polyurethane and prodigiosin are fully dissolved in the resin material, and are especially suitable for the synthetic leather process for the polyurethane base layer or the finishing layer.

An environment-friendly, antibacterial, mildew-proof dyed polyurethane resin, in parts by weight, consists of the following components in parts by weight:

Further preferably, the described environmentally-friendly, antibacterial, and mildew-proof dyed polyurethane resin consists of the following components by weight:

More preferably, the described environmentally friendly, antibacterial, mildew-proof dyed polyurethane resin consists of the following components by weight:

The invention adopts an in-situ dyeing method and uses an organic solvent as a dyeing medium to obtain a polyurethane material with good physical and mechanical properties, color fastness and antibacterial and antifungal effects.

The invention uses prodigiosin as coloring agent, supplemented with polyurethane resin and organic solvent of suitable weight to make dyed polyurethane slurry, wherein the prodigiosin is fully dissolved, and the performance of the slurry is stable. The dyed polyurethane slurry is used In the process of synthetic leather, it has good level dyeing property, good fastness to wet treatment, excellent antibacterial effect, and the obtained synthetic leather material has good softness and flexibility. In the environmentally friendly, antibacterial and mildew-proof dyed polyurethane resin of the present invention, commonly used auxiliary agents for preparing PU synthetic leather can be optionally added.

Prodigiosin belongs to fat-soluble biological dyes, easily soluble in organic solvents such as ethanol, dimethylformamide, acetone, ethyl acetate, tetrahydrofuran, 2-butanone, and polyurethane resin can also be dissolved in dimethylformamide, Acetone, 2-butanone, ethyl acetate, tetrahydrofuran and other organic solvents, so the co-solvent of the two can be selected as the dissolution medium, and after being prepared into a color paste, it is further processed to obtain a dyed polyurethane synthetic leather material with antibacterial and antifungal effects.

In addition, prodigiosin is obtained by inoculating, cultivating, fermenting and extracting a red pigment high-yielding strain. In its production process, the extraction of the purple-red thallus is carried out by using an organic solvent (such as ethanol, acetone, dimethylformamide, ethyl acetate, etc.) as a solvent. In order to simplify the process conditions, the extract of purple-red bacteria can be directly mixed with polyurethane resin to prepare polyurethane color paste. This approach can simplify the process while saving energy and reducing the amount of organic solvents used. The subsequent processing technology of synthetic leather can be directly applied to the traditional synthetic leather production line. The preparation of prodigiosin can adopt the Chinese patent application with application publication number CN 104789614A (application number 201510162982.9).

The prodigiosin can be a prodigiosin powder with a particle size of 0.5-2 μm, or a solution of prodigiosin from a culture medium bacterial secretion, and can be expanded and applied to other fat-soluble biological dyes.

The polyurethane resins can be commercially available products, specifically polyurethane resins with different moduli. The polyurethane resin may be polyester or polyether polyurethane resin, and its viscosity ranges from 500 to 5,000,000mpa.

Described organic solvent is at least one in ethanol, dimethylformamide, acetone, ethyl acetate, tetrahydrofuran, 2-butanone, and above-mentioned organic solvent can dissolve prodigiosin and polyurethane resin simultaneously, makes bleeding Red pigment and polyurethane resin can be uniformly mixed and fully dissolved to form a homogeneous system, so as to keep the performance of polyurethane color paste stable without cracking. Further preferably, the organic solvent is at least one of acetone, dimethylformamide, ethyl acetate, tetrahydrofuran, and ethanol.

Most preferably, the described environmentally friendly, antibacterial, antifungal, and antifungal stained polyurethane resin consists of the following components in parts by weight:

Described organic solvent is dimethylformamide.

A preparation method of polyurethane synthetic leather, comprising the following steps:

1) uniformly mixing prodigiosin, polyurethane resin, organic solvent and optional additives to obtain environmentally friendly antibacterial and mildew-proof dyed polyurethane resin;

2) The environmentally friendly, antibacterial, and mildew-resistant dyed polyurethane resin is coagulated by a wet process to obtain a wet-process polyurethane semi-finished leather, that is, the base layer of synthetic leather. After the surface of the base layer is finished, it becomes a finished product of polyurethane synthetic leather. Wet-process polyurethane synthetic leather has excellent performance, good air permeability, moisture permeability, smooth and plump feel, excellent mechanical strength, especially similar to natural leather in structure.

Another preparation method of polyurethane synthetic leather comprises the following steps:

1) uniformly mixing prodigiosin, polyurethane resin, organic solvent and optional additives to obtain environmentally friendly antibacterial and mildew-proof dyed polyurethane resin;

2) Apply the environmentally friendly, antibacterial, antifungal, and antifungal dyed polyurethane resin to the synthetic leather base cloth by coating, and then solidify, wash, and dry to obtain semi-finished polyurethane leather with a single coating method, that is, a single coating Fabei layer. Polyurethane synthetic leather is obtained after post-treatment. The single-coated Fabeis layer (single-coated polyurethane semi-finished leather) is often transferred and veneered by a dry method to form a polyurethane synthetic leather product, or polished by a dermabrasion machine to form a polyurethane synthetic leather product. In particular, the synthetic leather made of single-coated bass after dry transfer veneer has a wide variety of designs and colors. It can not only produce ordinary pattern leather, but also produce mirror leather, inner pattern leather, pearl leather, color printing mirror leather, etc. The drying condition is: drying at 60-120° C. for 1-5 minutes, and optimally, the drying condition is: drying at 90° C. for 3 minutes.

The use of wet-process polyurethane synthetic leather is the same as that of natural leather. It can be used for clothing, shoes, bags, ball games, etc.

Single-coated polyurethane semi-finished leather is mainly used in women's shoes, light shoes, purses, wallets, etc.

Therefore, the environmentally-friendly, antibacterial, and mildew-proof dyed polyurethane resin of the present invention can be used for the prepared synthetic leather, and the synthetic leather material can be applied to fields such as clothing, bags, footwear, sofas, and automotive interiors.

Compared with prior art, the beneficial effect of the present invention is:

(1) The present invention uses prodigiosin as a coloring agent, and dissolves prodigiosin and polyurethane resin in an organic solvent to make a polyurethane slurry, and a suitable solvent enables the prodigiosin and polyurethane resin to be uniformly mixed, Sufficiently dissolve to form a homogeneous system, so as to keep the performance of polyurethane color paste stable;

(2) The present invention can directly mix the extract (containing prodigiosin) of the fermented thalline of the red pigment high-yield strain with the polyurethane resin to prepare the polyurethane color paste. The application process is simple and convenient, the product performance is stable, and it has good antibacterial effect;

(3) The polyurethane color paste is used in the synthetic leather process, and the obtained synthetic leather material has uniform color, good physical and mechanical properties, good fastness to wet treatment, and excellent antibacterial effect.

Detailed ways

The present invention will be further described in detail below in combination with specific embodiments. In the embodiments of the present invention, unless otherwise specified, the parts mentioned are all parts by weight.

Example 1

Get each raw material of following parts by weight respectively:

Utilize the raw material of above-mentioned weight part to prepare printing paste, comprise the following steps:

(1) Grind 5 parts of prodigiosin with a ball mill to a fine powder with a particle size between 0.5 and 2 μm, add the fine powder to 15 parts of DMF (dimethylformamide), mix well, and obtain A liquid;

(2) PU solution prepared by mixing 20 parts of polyurethane resin with 60 parts of DMF to obtain liquid B;

(3) Add liquid A to liquid B, mix, beat, and homogenize to keep the pH value at a weakly acidic 6-6.5 to obtain PU color paste.

(4) Scrape-coat the PU color paste on the base cloth, then enter the wet coagulation bath, and then further wash and dry to obtain the PU leather wet fabric layer.

(5) Pour the PU color paste onto the polytetrafluoroethylene board by scraping, and then dry it to make a film with a thickness of about 0.05mm in order to test the mechanical properties of the PU material.

Performance Testing

The PU color paste prepared in the examples is used to prepare PU film materials, and the physical and mechanical properties, K/S value, color fastness to rubbing and color fastness to washing of the obtained PU leather are tested according to GB/T3920-2008 " Textile Color Fastness Test "Rubbing Fastness" Test the rubbing fastness, according to GB/T3921.3-2008 "Textile Color Fastness Test Color Fastness to Washing" Test the washing fastness.

Example 2

Take 0.01 part, 0.5 part, 2 parts, 8 parts, 10 parts of prodigiosin respectively, the parts by weight of other raw materials are the same as in Example 1, and the preparation method of PU color paste is the same as in Example 1. The method of step (5) in Example 1 was used to prepare the PU film material in order to test the application performance of the PU color paste, and the specific results are shown in Table 1.

Table 1 Effect of prodigiosin content on the color effect of PU leather

It can be seen from Table 1 that when the amount of prodigiosin is 0.01 part, its color is lighter. The amount of prodigiosin has little effect on the mechanical properties of PU leather, and basically maintains the original excellent physical and mechanical properties of PU leather. As the amount of prodigiosin increases, the color depth of PU synthetic leather increases, and the color is also brighter and fuller. When the amount of prodigiosin is more than 5 parts, the color of PU leather does not change much, so the optimal amount of prodigiosin is 5 parts (i.e. embodiment 1).

Example 3

Embodiment 1 adopts dimethylformamide (DMF) as solvent, uses 2-butanone (MEK) and ethanol (EA) respectively as solvent replacement dimethylformamide (DMF) in embodiment 1, all the other are the same as embodiment 1. Utilize the above-mentioned raw materials in parts by weight to prepare PU color paste, and then adopt a conventional finishing treatment process preparation method (step (5) method in Example 1) to prepare a PU finishing layer. The influence of solvent types on the color effect of PU leather is shown in Table 2.

Table 2 The effect of solvent types on the color effect of PU leather

As can be seen from Table 2, when DMF is used as the solvent, the mechanical properties of the PU material are excellent, the color is bright, the color is full, and the fastness to wet treatment is excellent. Therefore, the present invention selects DMF as the solvent.

Example 4

Among the polyurethane resins in Example 1, the polyurethane resins with a modulus of 30, 50, 100, and 240 mps (respectively labeled 1, 2, 3, and 4) are used to mix with prodigiosin, according to the method of step (5) of Example 1 The polyurethane film material was prepared and its performance was tested. The application properties of different kinds of colored PU film materials are shown in Table 3.

Table 3 Application properties of different kinds of colored PU film materials

It can be seen from Table 3 that when polyurethane resins with different moduli are selected for treatment, the color of the obtained PU leather is darker, and the color yield of prodigiosin is the highest. It is proved that prodigiosin can be applied to different classes of polyurethane resin coloring.

Example 5

Get the same weight of DMF as in Example 1 as the solvent, the types and parts by weight of other components are the same as in Example 1, the preparation method of the PU color paste material is the same as in Example 1, and different drying temperatures are used for the PU film. The material was dried for 3 minutes, and then its various performance indicators were tested. The specific results are shown in Table 4.

Table 4 The effect of drying temperature on the properties of PU leather

It can be seen from Table 4 that the washing fastness and wet rubbing fastness of the obtained colored PU leather are good, basically reaching level 4 or above. When the drying temperature is 120°C, although the indicators are basically above grade 3-4, the shade of colored leather changes, so the best drying temperature is 90°C.

Example 6

Get 0.01 part, 0.5 part, 2 parts, 5 parts (i.e. embodiment 1), 8 parts of prodigiosin respectively, the parts by weight of other raw materials are the same as in Example 1, and the preparation method of PU color paste is the same as in Example 1. Test the antibacterial properties of PU leather obtained with different prodigiosin concentrations, including: take Staphylococcus aureus, Candida albicans and E. Blow and blow the bacterium, pipette 100ml of bacterial suspension and apply it on the beef extract peptone medium plate, then cut each printed fabric into a small round cloth with a diameter of 2.5±0.5cm and place it on the coated plate, and use untreated The PU leather stained with prodigiosin was used as a negative control, and the results were observed after being inverted for 12 hours. The test results are shown in Table 5.

Table 5 Antibacterial performance test results of colored PU leather

It can be seen from Table 5 that when using the printing paste of Example 1, when the prodigiosin content is more than 0.5 parts, the obtained PU synthetic leather has good resistance to Escherichia coli, Staphylococcus aureus and Candida albicans.

Claims (2)

1. a kind of preparation method of the mould proof dyeing Synthetic Leather of environment-friendly antibacterial, which comprises the following steps:

(1) by the attritive powder that 5 parts of prodigiosin ball mill grindings to partial size are between 0.5~2 μm, which is added Enter into 15 parts of dimethylformamide, mix, obtains A liquid；

(2) the PU solution for being hybridly prepared into 20 parts of polyurethane resins and 60 parts of dimethylformamide obtains B liquid；

(3) A liquid is added in B liquid, is mixed with beating, is homogenized, its pH value is made to maintain 6~6.5 condition of faintly acid, obtain PU color Slurry；

(4) PU mill base is scratched onto synthetic leather base cloth, subsequently into wet coagulation bath, further washes, dries, obtain Polyurethane semi-finished product leather, then it is post-treated after obtain Synthetic Leather.

2. the preparation method of the mould proof dyeing Synthetic Leather of environment-friendly antibacterial according to claim 1, which is characterized in that institute The condition for the drying stated are as follows: in 60~120 DEG C of 1~5min of drying.