阅读说明：本技术 一种基于阻燃水基聚氨酯的阻燃超纤革基布的制备方法 (Preparation method of flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane ) 是由 范浩军 崔梦杰 陈意 颜俊 向均 李静 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种基于阻燃水基聚氨酯的阻燃超纤革基布的制备方法。其特征是合成了一种含三嗪基反应型阻燃扩链剂,利用化学反应将该扩链剂引入水基聚氨酯侧链,制备了一种阻燃水基聚氨酯,将所制备的阻燃水基聚氨酯与聚磷酸铵复合形成膨胀型阻燃含浸浆料浸渍海岛型超细纤维(简称超纤)无纺布,将浸渍有上述浆料的超纤无纺布置于凝固液中凝固,接着通过减量工艺去除海组分,水洗,干燥及后整理得到具有3D阻燃功能的超纤合成革基布。采用阻燃水性聚氨酯复合浆料替代传统的溶剂型聚氨酯含浸浆料,不仅提高了基布的阻燃性能,还从源头消除了VOCs污染,大大提升了合成革的品质、生态等级和国际市场竞争力。(阻燃扩链剂结构式)。(The invention discloses a preparation method of flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane. The method is characterized in that a triazine group-containing reactive flame-retardant chain extender is synthesized, the chain extender is introduced into a water-based polyurethane side chain by utilizing a chemical reaction to prepare flame-retardant water-based polyurethane, and the prepared flame-retardant water-based polyurethane is compounded with ammonium polyphosphate to form a compositeAnd (2) impregnating the sea-island type superfine fiber (microfiber for short) non-woven fabric with the intumescent flame-retardant impregnating slurry, solidifying the microfiber non-woven fabric impregnated with the slurry in a solidification solution, removing sea components by a decrement process, washing, drying and finishing to obtain the microfiber synthetic leather base fabric with the 3D flame-retardant function. The flame-retardant waterborne polyurethane composite slurry is adopted to replace the traditional solvent type polyurethane impregnating slurry, so that the flame retardant property of the base cloth is improved, the VOCs pollution is eliminated from the source, and the quality, the ecological grade and the international market competitiveness of the synthetic leather are greatly improved.)

1. The preparation method of the flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane is characterized by comprising the following steps of:

(1) preparing a flame-retardant chain extender: dissolving 36.9g of cyanuric chloride in acetone, adding 33.6g of sodium bicarbonate, then dropwise adding 12.8g of methanol, reacting for 4 hours at 20 ℃, washing, filtering and drying the prepared product; adding the prepared product and 2-amino-2-methyl-1, 3-propanediol into acetonitrile, adding 27.9g of triethylamine, reacting at 82 ℃ for 6 hours, washing, filtering and drying the product to obtain (4, 6-dimethoxy-1, 3, 5-triazine) -2-methylpropane-1, 3-diol;

(2) preparation of flame-retardant water-based polyurethane: adding 60-100 parts of polyether polyol, 30-50 parts of aromatic or aliphatic diisocyanate and 0.01 part of catalyst bismuth laurate into a reaction container, and heating to 75-85 ℃ under the conditions of continuous stirring and nitrogen atmosphere protection to react for 2-3 hours to obtain a prepolymer; adding 4-8 parts of hydrophilic chain extender into the obtained prepolymer andN,N5-10 parts of dimethylformamide, reacting for 2-3 hours at the temperature of 75-85 ℃, and mixing 20-30 parts of flame-retardant chain extender withN,N10-20 parts of-dimethylformamide is added into the prepolymer, and the mixture is continuously reacted for 2-3 hours at the temperature of 75-85 ℃ to obtain the prepolymer which contains flame retardant components and is terminated by-NCO; neutralizing the prepolymer with 4-8 parts of triethylamine, and dispersing the prepolymer in deionized water under the action of high shear force to obtain a flame-retardant water-based polyurethane emulsion (the solid content is 20-30%);

(3) preparing a flame-retardant water-based polyurethane-based microfiber synthetic leather base fabric: compounding 100 parts of flame-retardant water-based polyurethane, 1-5 parts of water-based thickening agent, 0.5-3 parts of foam cell adjusting auxiliary agent and 5-10 parts of ammonium polyphosphate to prepare impregnated polyurethane slurry; and (2) impregnating the island-type superfine fiber non-woven fabric in the prepared impregnated polyurethane slurry, then extruding by a roller, scraping the surface impregnation solution by a scraper, solidifying in a solidification solution, drying, then performing alkali decrement, washing and drying to obtain the flame-retardant superfine fiber synthetic leather base fabric based on the flame-retardant water-based polyurethane slurry.

2. The method for preparing flame-retardant microfiber leather substrate based on flame-retardant water-based polyurethane as claimed in claim 1, wherein said polyether polyol is one or combination of number average molecular weight 2000-4000, alkaline hydrolysis-resistant polytetrahydrofuran glycol, polycarbonate glycol and polypropylene glycol.

3. The method of claim 1, wherein the sea-island type microfiber nonwoven fabric is of an alkali-reduced type, and is classified into one of PET/COPET type, PA6/COPET type, and PA6/PET type according to the sea-island fiber components.

4. The method for preparing the flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane according to claim 1, wherein the weight reduction process is an alkali weight reduction process.

5. The method for preparing the flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane as claimed in claim 1, wherein the solidification liquid is 5-10% of CaCl₂Or (NH)₄）₂SO₄Any of the solutions.

Technical Field

The invention particularly relates to a preparation method of flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane, and belongs to the field of functional synthetic leather manufacturing.

Background

The superfine fiber synthetic leather is a composite material developed based on dissolved sea island type superfine fibers and consists of superfine fibers and polyurethane. The superfine fiber is in a bundle shape, and the fineness and the structure are similar to those of collagen fiber. The superfine fibers are three-dimensionally interwoven in the superfine fiber synthetic leather and used as a framework to play a supporting role; the polyurethane distributed around the fiber enables the whole synthetic leather base cloth to form an organic whole, the polyurethane has filling performance in the base cloth, and forms circular, fingerprint-shaped or honeycomb-shaped cellular structures which are communicated in a staggered mode, so that the superfine fiber synthetic leather has good air permeability, moisture permeability and plumpness similar to leather. The superfine fiber synthetic leather has almost all the advantages of natural leather, is better than the natural leather in the aspects of temperature resistance, texture uniformity, mechanical strength and the like, and becomes a high-grade substitute of the natural leather.

The manufacturing technology of the superfine fiber synthetic leather in China starts late, approximately in the 90 th 20 th century, although the technology is developed rapidly, most of the manufacturing technology is in a follow-up level, the homogenization is serious, and products with high physical properties and functionality are still in the stages of exploration and development. Compared with the national with technical advantages such as Japan, the superfine fiber synthetic leather product in China still has certain gap, so the innovation of accelerating the manufacturing technology of the superfine fiber synthetic leather in China is imperative, and the change from the large country manufactured by the superfine fiber leather to the strong country manufactured by the superfine fiber leather in China can be promoted.

Automobile leather, airplane seat leather, home decoration leather and the like have high requirements on flame retardance. However, the flame retardant property of the superfine fiber synthetic leather is poor, and certain potential safety hazard exists in the using process. Especially, during the combustion process, a large amount of toxic gases such as carbon monoxide and the like can be released, and once a fire disaster happens, the escape time can be shortened. Therefore, it is very important to develop a high-performance flame-retardant superfine fiber synthetic leather material. Chinese patent No. CN 203514091U discloses a preparation method of flame-retardant microfiber synthetic leather, wherein a flame-retardant polyurethane layer and an organic silicon layer are used as flame-retardant layers, and the flame-retardant polyurethane layer is arranged on the organic silicon layer, so that the flame retardant property of the microfiber synthetic leather is improved. But the microfiber leather consists of base cloth and a coating, only the coating has flame retardant property, the base cloth does not have flame retardant property, and the overall flame retardant property does not meet the market requirement. To a large extent, substrate flame retardancy, particularly long-lasting flame retardancy, is the key and basis for determining the flame retardancy of finished leather. Chinese patent No. CN 209395371U discloses a preparation method of microfiber flame-retardant fiber leather for automotive interiors, melamine cyanurate is used as a flame retardant and is placed in a flame-retardant coating, and an iron wire mesh layer is covered above the flame-retardant coating to prepare the microfiber flame-retardant fiber leather with high flame-retardant performance. However, the melamine micromolecule flame retardant is easy to migrate to the surface in the synthetic leather, and is easy to generate blooming after being used for a period of time, so that the flame retardant performance is reduced. Intumescent flame retardant systems are increasingly gaining importance due to their high flame retardant efficiency. The intumescent flame retardant system consists of an acid source, a carbon source and a gas source, wherein the acid source captures oxygen radicals and the like generated during combustion to quench the combustion reaction; the carbon source promotes the carbon formation to form a more compact carbon protective layer; the gas source releases a non-combustible gas. The three parts are mutually cooperated, so that the flame retardant property of the microfiber synthetic leather can be greatly improved, but the synergistic effect of three sources is rarely considered in the conventional microfiber leather flame retardant system.

Disclosure of Invention

The invention aims to provide a preparation method of flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane, aiming at the defects of the prior art. Firstly, a triazine group-containing reactive flame-retardant chain extender is synthesized, the chain extender is introduced into a water-based polyurethane side chain by utilizing a chemical reaction to prepare flame-retardant water-based polyurethane, the prepared flame-retardant water-based polyurethane is compounded with ammonium polyphosphate to form an intumescent flame-retardant impregnating slurry impregnated microfiber non-woven fabric, and the microfiber synthetic leather base fabric is obtained after solidification, decrement, washing, drying and after-finishing. The flame-retardant chain extender is grafted to a macromolecular chain through chemical bonding, and the defects that small molecular flame retardants (melamine and the like) are easy to migrate and are easy to separate out in a decrement process in a common intumescent flame-retardant system are overcome. The obtained flame retardant does not contain halogen, the triazine ring containing carbon and nitrogen and ammonium polyphosphate have good synergistic effect, the triazine ring provides a carbon source and a gas source, the ammonium polyphosphate is used as an acid source, and a three-source synergistic intumescent flame retardant system is formed in the base cloth; meanwhile, a 3D (three-dimensional) flame-retardant network is obtained by means of a special impregnation-reduction process of the microfiber base fabric, and the prepared microfiber synthetic leather base fabric has good 3D flame-retardant performance.

The invention provides a preparation method of flame-retardant microfiber leather base cloth based on flame-retardant water-based polyurethane, which is characterized by comprising the following steps of:

(1) preparing a flame-retardant chain extender: 36.9g of cyanuric chloride was dissolved in acetone, 33.6g of sodium hydrogencarbonate was added, and then 12.8g of methanol was added dropwise to react at 20 ℃ for 4 hours. Washing, filtering and drying the prepared product; adding the prepared product and 2-amino-2-methyl-1, 3-propanediol into acetonitrile, adding 27.9g of triethylamine, reacting at 82 ℃ for 6 hours, washing, filtering and drying the product to obtain (4, 6-dimethoxy-1, 3, 5-triazine) -2-methylpropane-1, 3-diol;

the specific reaction equation in the above method is shown in figure 2.

(2) Preparation of flame-retardant water-based polyurethane: adding 60-100 parts of polyether polyol, 30-50 parts of aromatic or aliphatic diisocyanate and 0.01 part of catalyst bismuth laurate into a reaction container, and heating to 75-85 ℃ under the conditions of continuous stirring and nitrogen atmosphere protection to react for 2-3 hours to obtain a prepolymer; adding 4-8 parts of hydrophilic chain extender into the obtained prepolymer andN,N5-10 parts of dimethylformamide, reacting for 2-3 hours at the temperature of 75-85 ℃, and mixing 20-30 parts of flame-retardant chain extender withN,N10-20 parts of dimethylformamide is added into the prepolymer, and the reaction is continued at 75-85 ℃ for 2-3 hours, obtaining a prepolymer containing a flame-retardant component and terminated by-NCO; neutralizing the prepolymer with 4-8 parts of triethylamine, and dispersing the prepolymer in deionized water under the action of high shear force to obtain a flame-retardant water-based polyurethane emulsion (the solid content is 20-30%);

(3) preparing a flame-retardant water-based polyurethane-based microfiber synthetic leather base fabric: compounding 100 parts of flame-retardant water-based polyurethane, 1-5 parts of water-based thickening agent, 0.5-3 parts of foam cell adjusting auxiliary agent and 5-10 parts of ammonium polyphosphate to prepare impregnated polyurethane slurry; and (2) impregnating the island-type superfine fiber non-woven fabric in the prepared impregnated polyurethane slurry, then extruding by using a roller, scraping the surface impregnation solution by using a scraper, solidifying in a solidification solution, drying, then performing alkali decrement, washing and drying to obtain the 3D flame-retardant superfine fiber synthetic leather base fabric based on the flame-retardant water-based polyurethane slurry.

The polyether polyol in the method is one or the combination of 2000-4000 of number average molecular weight, polytetrahydrofuran glycol resistant to alkaline hydrolysis, polycarbonate glycol and polypropylene glycol.

The sea-island type superfine fiber non-woven fabric in the method is alkali-reduced, and is divided into one of PET/COPET type, PA6/COPET and PA6/PET type according to the sea-island fiber components.

The sea-island type superfine fiber non-woven fabric in the method is subjected to a weight reduction process and an alkali weight reduction process.

In the method, the solidification liquid is 5-10% of CaCl₂Or (NH)₄）₂SO₄Any of the solutions.

Compared with the prior art, the invention has the following positive effects:

(1) the triazine group is grafted to the side chain of the polyurethane molecule by utilizing a chemical reaction, the defects that small molecular flame retardants (melamine and the like) are easy to migrate and are not resistant to alkali reduction in a common intumescent flame retardant system are overcome, and the prepared microfiber base cloth has lasting flame retardance.

(2) In the aspect of molecular design, triazine ring is used for providing a carbon source and a gas source, ammonium polyphosphate is used for providing an acid source, the three sources cooperate with the base cloth to form an intumescent flame retardant system, and the flame retardant does not contain halogen, so that the prepared microfiber synthetic leather base cloth has good flame retardant property.

(3) The flame-retardant water-based polyurethane composite slurry is soaked into the microfiber base cloth in an impregnation mode and reduced to form a skeleton with a honeycomb structure, so that the microfiber synthetic leather base cloth has 3D (three-dimensional) flame retardant performance, and the problem that the flame retardant performance is reduced after a traditional flame-retardant coating is abraded is solved.

(4) The flame-retardant microfiber synthetic leather base cloth prepared by the invention adopts the flame-retardant waterborne polyurethane composite slurry to replace the traditional solvent type polyurethane impregnating slurry, so that the emission of VOCs in the microfiber synthetic leather preparation process is greatly reduced, and the flame-retardant microfiber synthetic leather base cloth has the outstanding characteristics of environmental protection, health, safety and the like.

Drawings

Description of the drawings fig. 1: a reaction equation of the triazine-based flame-retardant chain extender; description of the drawings fig. 2: a preparation method of a flame-retardant chain extender.

Detailed Description

The present invention is described in detail by the following embodiments, it should be noted that the following embodiments are only used for further illustration of the present invention, and should not be construed as limiting the scope of the present invention, and those skilled in the art can make some insubstantial modifications and adaptations based on the above disclosure, and still fall within the scope of the present invention.

Example 1:

(1) preparing a flame-retardant chain extender: dissolving 36.9g of cyanuric chloride in acetone, adding 33.6g of sodium bicarbonate, then dropwise adding 12.8g of methanol, reacting for 4 hours at 20 ℃, washing, filtering and drying the prepared product; adding the prepared product and 2-amino-2-methyl-1, 3-propanediol into acetonitrile, adding 27.9g of triethylamine, reacting at 82 ℃ for 6h, washing, filtering and drying the product to obtain (4, 6-dimethoxy-1, 3, 5-triazine) -2-methylpropane-1, 3-diol.

(2) Preparation of flame-retardant water-based polyurethane: adding 60 parts of polytetrahydrofuran diol, 30 parts of 4, 4' -diphenylmethane diisocyanate and 0.01 part of bismuth laurate into a reaction vessel, and heating to 75 ℃ under the conditions of continuous stirring and nitrogen atmosphere protectionReacting for 2 hours to obtain a prepolymer; then 4 parts of dimethylolpropionic acid andN,N-5 parts of dimethylformamide and maintaining at 75 ℃ for 2 hours; then 20 parts of flame-retardant chain extender andN,Nadding 10 parts of dimethylformamide into the prepolymer, and continuously reacting for 2 hours at 75 ℃ to obtain a prepolymer containing a flame-retardant component and terminated by-NCO; and finally, neutralizing the prepolymer with 4 parts of triethylamine, and dispersing the prepolymer in 400g of deionized water under the action of high shear force to obtain the flame-retardant water-based polyurethane emulsion (the solid content is 20%).

(3) Preparing a flame-retardant water-based polyurethane-based microfiber synthetic leather base fabric: compounding 100 parts of flame-retardant water-based polyurethane, 1 part of aqueous thickening agent, 0.5 part of cell regulating additive and 5 parts of ammonium polyphosphate to prepare impregnated polyurethane slurry; and then, impregnating the PA6/COPET type superfine fiber non-woven fabric in the impregnated polyurethane slurry prepared in the previous step, extruding by using a roller, scraping off the surface impregnation solution by using a scraper, then placing the surface impregnation solution in a solidification solution for solidification, drying, then carrying out alkali decrement, washing and drying to obtain the flame-retardant superfine fiber synthetic leather base fabric based on the flame-retardant water-based polyurethane slurry.

Compared with a blank sample (the superfine fiber synthetic leather base cloth impregnated by the water-based polyurethane without the flame retardant), the Limit Oxygen Index (LOI) of the prepared superfine fiber synthetic leather base cloth is improved from 17.2 percent to 25.3 percent, the vertical combustion self-extinguishing time is 6 seconds, and no dripping exists; after the flame-retardant base cloth is abraded for 500 times by the Martindale method, the flame-retardant efficiency is still kept to be 98.9 percent, the flame-retardant efficiency is high, and the flame-retardant base cloth has lasting flame-retardant performance.

Example 2:

(1) preparing a flame-retardant chain extender: dissolving 36.9g of cyanuric chloride in acetone, adding 33.6g of sodium bicarbonate, then dropwise adding 12.8g of methanol, reacting for 4 hours at 20 ℃, washing, filtering and drying the prepared product; adding the prepared product and 2-amino-2-methyl-1, 3-propanediol into acetonitrile, adding 27.9g of triethylamine, reacting at 82 ℃ for 6h, washing, filtering and drying the product to obtain (4, 6-dimethoxy-1, 3, 5-triazine) -2-methylpropane-1, 3-diol.

(2) Preparation of flame-retardant water-based polyurethane: mixing polypropylene glycol 8Adding 0 part of hexamethylene diisocyanate, 40 parts of hexamethylene diisocyanate and 0.01 part of bismuth laurate into a reaction container, and heating to 80 ℃ under the continuous stirring and the protection of nitrogen atmosphere to react for 2.5 hours to obtain a prepolymer; then 6 parts of dimethylolbutyric acid andN,N-7.5 parts of dimethylformamide, and maintaining the temperature at 80 ℃ for 2.5 hours; then 25 parts of flame-retardant chain extender andN,Nadding 15 parts of dimethylformamide into the prepolymer obtained in the previous step, and continuously reacting for 2.5 hours at 80 ℃ to obtain a prepolymer containing a flame-retardant component and terminated by-NCO; preferably, 6 parts of triethylamine is used to neutralize the prepolymer and the prepolymer is dispersed in 300g of deionized water under high shear to provide a flame retardant waterborne polyurethane emulsion (25% solids).

(3) Preparing a flame-retardant water-based polyurethane-based microfiber synthetic leather base fabric: compounding 100 parts of flame-retardant water-based polyurethane, 3 parts of water-based thickening agent, 1 part of cell regulating additive and 7.5 parts of ammonium polyphosphate together to prepare impregnated polyurethane slurry; and then, impregnating the PA6/PET type superfine fiber non-woven fabric in the impregnated polyurethane slurry prepared in the previous step, extruding by using a roller, scraping off the surface impregnated liquid by using a scraper, solidifying in a solidification liquid, drying, reducing alkali, washing and drying to obtain the flame-retardant superfine fiber synthetic leather base fabric based on the flame-retardant water-based polyurethane slurry.

Compared with a blank sample (the superfine fiber synthetic leather base cloth impregnated by the water-based polyurethane without the flame retardant), the Limit Oxygen Index (LOI) of the prepared superfine fiber synthetic leather base cloth is improved from 17.2 percent to 27.9 percent, the vertical combustion self-extinguishing time is 5 seconds, and no dripping exists; after the finished leather is abraded for 500 times by the Martindale method, the flame retardant efficiency of the finished leather is still kept to be 99.1 percent, the flame retardant efficiency is high, and the finished leather has lasting flame retardant property.

Example 3:

(1) preparing a flame-retardant chain extender: dissolving 36.9g of cyanuric chloride in acetone, adding 33.6g of sodium bicarbonate, then dropwise adding 12.8g of methanol, reacting for 4 hours at 20 ℃, washing, filtering and drying the prepared product; adding the prepared product and 2-amino-2-methyl-1, 3-propanediol into acetonitrile, adding 27.9g of triethylamine, reacting at 82 ℃ for 6h, washing, filtering and drying the product to obtain (4, 6-dimethoxy-1, 3, 5-triazine) -2-methylpropane-1, 3-diol.

(2) Preparation of flame-retardant water-based polyurethane: adding 100 parts of polyethylene glycol, 50 parts of isophorone diisocyanate and 0.01 part of bismuth laurate into a reaction container, and heating to 85 ℃ for reaction for 3 hours under the conditions of continuous stirring and nitrogen atmosphere protection to obtain a prepolymer; then 2- [ (2-aminoethyl) amino group was added to the prepolymer obtained]8 parts of ethanesulfonic acid sodium salt andN,N10 parts of dimethylformamide, and maintaining at 85 ℃ for 3 hours; then 30 parts of flame-retardant chain extender andN,Nadding 20 parts of dimethylformamide into the prepolymer obtained in the previous step, and continuously reacting for 3 hours at 85 ℃ to obtain a prepolymer containing a flame-retardant component and terminated by-NCO; finally, neutralizing the prepolymer with 8 parts of triethylamine, and dispersing the prepolymer in 235g of deionized water under the action of high shear force to obtain the flame-retardant water-based polyurethane emulsion (the solid content is 30%).

(3) Preparing a flame-retardant water-based polyurethane-based microfiber synthetic leather base fabric: compounding 100 parts of flame-retardant water-based polyurethane, 5 parts of water-based thickening agent, 3 parts of cell regulating additive and 10 parts of ammonium polyphosphate together to prepare impregnated polyurethane slurry; then, arranging PET/COPET type superfine fiber non-woven fabric in the impregnated polyurethane slurry prepared in the previous step for impregnation, then extruding by a roller, and scraping off the surface impregnation liquid by a scraper; and placing the fabric into a solidification solution for solidification, drying, then carrying out alkali decrement, washing and drying to obtain the flame-retardant microfiber synthetic leather base fabric based on the flame-retardant water-based polyurethane slurry.

Compared with a blank sample (the superfine fiber synthetic leather base cloth impregnated by the water-based polyurethane without the flame retardant), the Limit Oxygen Index (LOI) of the prepared superfine fiber synthetic leather base cloth is improved from 17.2 percent to 30.1 percent, the vertical combustion self-extinguishing time is 5 seconds, and no dripping exists; after the finished leather is abraded for 500 times by the Martindale method, the flame retardant efficiency of the finished leather is still kept to be more than 99.7 percent, the flame retardant efficiency is high, and the finished leather has lasting flame retardant property.