CN109371670B - Flame retardant silk and its preparation method and application - Google Patents

Abstract

The invention discloses a method for preparing flame-retardant silk, which comprises the following steps: preparing a dioscorea cirrhosa extracting solution, and adsorbing condensed tannin in the dioscorea cirrhosa extracting solution on a silk fabric by using a dipping adsorption method to obtain a dioscorea cirrhosa extract modified silk fabric; and under the alkalescent condition, adsorbing the polypropylenimine dendrimer onto the silk fabric modified by the dioscorea cirrhosa extract by using a dipping adsorption method to obtain the flame-retardant silk. According to the invention, the crosslinking reaction of condensed tannin in the dioscorea cirrhosa extract and the polypropyleneimine dendrimer on the silk fabric under the alkalescent condition is utilized, so that the flame retardant property of the silk fabric is effectively improved, and the silk fabric finished by the method has a very good durable flame retardant function.

Description

Flame retardant silk and its preparation method and application

technical field

The invention relates to the technical field of textile finishing, in particular to a method for improving the flame-retardant properties of silk, flame-retardant silk and applications thereof.

Background technique

Nearly half of the world's fires are caused by the burning of textiles, and the number of fire deaths caused by textiles and upholstery is the highest. Silk is a natural protein fiber, which has the characteristics of moisture absorption and breathability, soft and smooth, soft luster, elegant and gorgeous, and comfortable to wear, so it is very popular and loved by people. Silk fiber is often widely used to make high-end bed textiles, upholstery fabrics, carpets, curtains, wall coverings and textile artworks, etc. These silk products have certain flame retardant requirements. Although silk has a certain flame retardancy compared with cellulose fibers, its limiting oxygen index is generally only about 23%, which is far from the standard of flame-retardant textiles, and it is difficult to meet people's expectations for flame-retardant silk products. Growing consumer demand. In order to improve the flame retardant properties of silk products, it is necessary to carry out flame retardant finishing.

The flame retardants used in protein fiber (mainly silk and wool) products are mainly divided into two categories: inorganic flame retardants and organic flame retardants. The commercial inorganic flame retardants are mainly metal compounds of zirconium and titanium, which are usually used in the flame retardant finishing of wool, and their washing durability is poor when applied to silk. Organic flame retardants can be applied to flame retardant finishing of almost all textiles, occupying a major market share. The organic flame retardants that have been used and are being used include compounds of bromine, chlorine, phosphorus and nitrogen. Although many commercial organic flame retardants can endow silk with flame retardant function, many of them do not meet the requirements of environmental protection and are even toxic. For example, halogen compounds will produce a large amount of toxic gases during combustion, and have a series of serious problems such as persistence, bioaccumulation and environmental toxicity, so they have been banned in the textile industry. Organophosphorus flame retardants have been widely used as a substitute for halogen flame retardants. However, during the use and washing process of flame-retardant textiles finished with organophosphorus flame retardants, the discharged waste liquid contains phosphorus-based compounds, which will lead to eutrophication of water bodies, and many phosphorus-based flame retardants contain hydroxyl groups. Methyl can cause formaldehyde emission problems. At present, the industry still uses organophosphorus flame retardants, zirconium and titanium metal compounds to carry out flame retardant finishing of silk products. Due to the awareness of the hazards of flame retardants and the sustainable development of the environment, the development of new eco-friendly and efficient flame retardants to replace traditional flame retardant compounds has become the development direction of flame retardants and their flame retardant finishing technology.

Chinese invention patent CN201710161634.9 discloses a method for dyeing and finishing protein fibers with phytic acid, using natural product phytic acid as an environment-friendly dyeing accelerator and flame retardant finishing agent, and the processed protein fibers have good flame retardant performance (limiting oxygen index is as high as 30%, the damage length during vertical combustion is less than 15cm, which can meet the B1-level flame retardant performance requirements in my country's "Flame Retardant Decorative Fabrics"), but the protein fiber products treated with phytic acid alone Inadequate washing durability of flame retardant function of Cleaner Production, 2018, 198:1044-1052). Chinese invention patent 201710568421.8 discloses a method for durable and flame-retardant finishing of silk fabrics by using a mixture of diospyross radix water extract, citric acid, sodium citrate and sodium formate. After high-temperature baking, washing and drying, durable flame-retardant silk fabrics are obtained. The limiting oxygen index of the flame-retardant silk fabrics can reach 27-28%, the damage length is less than 15cm when vertically burning, and after 20 repeated washings, the resistance The limit oxygen index of the flame-retardant silk fabric can still reach 27-28%, and the damage length is still less than 15cm when it is burned vertically. Compared with the unfinished silk fabric, the limit oxygen index of the flame-retardant silk fabric is still limited and cannot reach 30%. The above problem is an urgent problem to be solved in the art.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for improving the flame retardant performance of silk by utilizing the combined treatment of the diospyrosa diosica extract and the polypropylene imine dendrimer to improve the flame retardant performance of silk fabrics.

In order to solve the above-mentioned technical problems, the scheme provided by the invention is: the method for preparing flame-retardant silk, which is characterized in that, comprising the following steps:

S1, the silk is immersed in the described Dioscorea sativa extract, and is heated to 75-90 ℃ for processing, obtains the silk fabric modified by condensation tannin;

S2, immerse the described silk fabric modified by condensed tannin into the polypropyleneimide dendrimer solution with pH value of 8-9.5 and concentration of 5-15g/L, and heat to 55-70°C for treatment, Fire-retardant silk is obtained.

The present application utilizes the cross-linking reaction of the condensed tannins in the diospyross extract and the polypropyleneimine dendrimers on silk fabrics under weak alkaline conditions to endow silk fabrics with good durability and flame retardant function.

Further: the step S1 also includes preparing the extract of the diospyross sativa, including the following steps: placing the tubers of the diospyross sativa in a weight ratio of 15/100-30/100 in water for beating, and adjusting the pH value of the slurry to 8 , heated to 85-95 ℃ for 50-80min, and filtered to obtain the extract of Dioscorea sativa.

Further: the time of the heating treatment in the step S1 is 70-120min.

Further: in the step S2, the time of the heating treatment is 30-40min.

Further: the used polypropylene imine dendrimer is the second generation polypropylene imine dendrimer or the third generation polypropylene imine dendrimer.

Further: the used polypropylene imine dendrimer is the second generation polypropylene imine dendrimer or the third generation polypropylene imine dendrimer.

The present application further provides a flame-retardant silk prepared by the above method.

The present application further provides the application of the above flame retardant silk in weaving.

Beneficial effects of the present invention: the diosca chinensis extract used in the present invention is safe and non-toxic, the polypropyleneimine dendrimer has many reactive points, and the condensed tannin and the polypropyleneimine dendrimer in the diospyross sativa extract can be weakly Condensation and cross-linking reaction occurs rapidly under alkaline conditions, and the cross-linked product can be well combined with silk fibers, ensuring the washing durability of the flame retardant function; the cross-linked product of condensed tannin and polypropyleneimine dendrimer has a high Good high temperature stability and carbon-forming ability enable the silk fabric to have strong carbon-forming ability during combustion; the invention has simple process and convenient operation, and the finished silk fabric has excellent flame retardant effect and good durability.

Detailed ways

The present invention will be further described below with reference to specific embodiments, so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

Example 1

S1, prepare diospyross sativa extract and use the diospyross sativa extract to modify silk fabrics:

Wash, peel and chop the yam tubers. Weigh 150g of chopped Dioscorea tubers, add 500mL of water, mechanically pulverize and make pulp, adjust the pH value of the slurry to 8 with soda ash, heat to 85°C, soak for 80min, then stand, cool, and filter; in the filtrate, add water to dilute, Stir evenly, and set the volume to 1L to obtain the Dioscorea sativa extract. Through the above steps, the tannin condensation in the diospyross can be extracted, and the tannin condensation is dissolved in water.

According to the liquor ratio of 1:50, the amount of the above-mentioned Dioscorea sativa extract and silk was prepared. The silk was immersed in the extract of Dioscorea sativa, and the treatment was started from 30 °C, and gradually heated to 90 °C at a heating rate of 2 °C/min, and the temperature was maintained for 70 min. After soaking treatment, the silk was taken out and washed with water to obtain a silk fabric modified by the extract of Dioscorea officinalis.

S2, using polypropyleneimide dendrimer to process the silk fabric modified by Dioscorea sativa extract:

A solution of third-generation polypropyleneimine dendrimer (molecular weight: 1687 g/mol) with a concentration of 5 g/L was prepared, and the pH value of the solution was adjusted to 9.5 with acetic acid and soda ash to obtain a polypropyleneimine dendrimer solution.

The silk and polypropyleneimide dendrimer solutions were prepared in a liquor ratio of 1:50. The silk fabric modified with diospyross turmeric was immersed in the polypropyleneimide dendrimer solution, and the treatment was started from 30 °C, and gradually heated to 55 °C at a heating rate of 2 °C/min, and the temperature was maintained for 40 min. After the treatment, the silk was taken out, rolled with water, and dried at 80° C. to obtain a flame-retardant silk fabric.

Example 2

S1. Wash, peel and chop the yam tubers. Weigh 75g of chopped Dioscorea tubers, add 500mL of water, mechanically pulverize and make pulp, adjust the pH value of the slurry to 8 with soda ash, heat to 95°C, soak for 50min, then stand, cool, and filter; in the filtrate, add water to dilute, Stir evenly, and set the volume to 1L to obtain the Dioscorea sativa extract. According to the liquor ratio of 1:50, the amount of the above-mentioned Dioscorea sativa extract and silk was prepared. The silk was immersed in the extract of Dioscorea officinalis, and the treatment was started from 30 °C, and the temperature was gradually increased to 75 °C at a heating rate of 2 °C/min, and the temperature was maintained for 120 min. After soaking treatment, the silk was taken out and washed with water to obtain a silk fabric modified by the extract of Dioscorea officinalis.

S2. Prepare a solution of a second-generation polypropyleneimine dendrimer (molecular weight: 777 g/mol) with a concentration of 10 g/L, and adjust the pH of the solution to 8 with acetic acid and soda ash to obtain a polypropyleneimine dendrimer solution. The silk and polypropyleneimide dendrimer solutions were prepared in a liquor ratio of 1:50. The silk fabric modified with diospyross turmeric was immersed in the polypropyleneimide dendrimer solution, and the treatment was started at 30 °C, and was gradually heated to 70 °C at a heating rate of 2 °C/min, and the temperature was maintained for 30 min. After the treatment, the silk was taken out, rolled with water, and dried at 80° C. to obtain a flame-retardant silk fabric.

Example 3

S1. Wash, peel and chop the yam tubers. Weigh 125g of chopped Dioscorea tubers, add 500mL of water, mechanically pulverize and make pulp, adjust the pH of the slurry to 8 with soda ash, heat to 90°C, soak for 65min, then stand, cool, filter; in the filtrate, add water to dilute , stir evenly, and set the volume to 1L to obtain the Dioscorea sativa extract. The silk and polypropyleneimide dendrimer solutions were prepared in a liquor ratio of 1:50. The silk was immersed in the Dioscorea sativa extract, and the treatment was started at 30°C, and the temperature was gradually increased to 85°C at a heating rate of 2°C/min, and the temperature was maintained for 90 minutes. After soaking treatment, the silk was taken out and washed with water to obtain a silk fabric modified by the extract of Dioscorea officinalis.

S2, configure 15g/L of the second-generation polypropyleneimine dendrimer solution (molecular weight is 777g/mol), adjust the pH value of the solution to 8.5 with acetic acid and soda ash to obtain a polypropyleneimine dendrimer solution. The amount of polypropyleneimide dendrimer solution and silk was prepared according to the liquor ratio of 1:50. The silk fabric modified by diospyross turmeric was immersed in the solution of polypropyleneimide dendrimer, and the treatment was started at 30 °C, and was gradually heated to 60 °C at a heating rate of 2 °C/min, and the temperature was maintained for 30 min. After the treatment, the silk was taken out, rolled with water, and dried at 80° C. to obtain a flame-retardant silk fabric.

The flame retardant properties and washing resistance properties of the flame retardant silk fabrics obtained in the above examples 1 to 3 were tested.

Among them, the flame retardant performance is evaluated by the limiting oxygen index and the damage length during vertical combustion; the limiting oxygen index of the fabric is determined according to the standard GB/T 5454-1997 "Textile Combustion Performance Experiment Oxygen Index Method", and the damage length of the fabric during vertical combustion is determined by GB/T 5455-2014 "Determination of vertical damage length of smoldering and after-burning time of textile combustion performance" standard; the combustion performance of fabrics is evaluated according to GB/T 17591-2006 "flame retardant fabric" standard. The water washing method of flame retardant fabrics is carried out according to GB/T 3921-2008 "Textile Color Fastness Test Color Fastness to Soaping". Once, repeat the washing to the desired number of washes.

For the convenience of comparison, the application is also provided with the following comparison samples;

Control 1: Untreated silk fabric was used.

Control sample 2: silk fabric treated with 10 g/L second-generation polypropyleneimide dendrimer at 70° C. for 30 min alone.

Control sample 3: silk fabric treated with Dioscorea officinalis extract alone, specifically the silk fabric treated only in step S1 in Example 1.

The final test results are shown in Table 1.

Table 1 Flame retardant properties of silk fabrics

It can be seen from Table 1 that the limiting oxygen index of the silk fabric without any treatment is 24.5%, it is completely burned in the vertical combustion process, and the damage length is 30cm, which belongs to the non-flame retardant fabric. The silk fabric treated with polypropyleneimide dendrimer alone has a certain degree of improvement in the limiting oxygen index, but it is also completely burned when it is vertically burned, and the damage length is 30cm, which is a non-flame retardant fabric. The limiting oxygen index of the silk fabric treated with the extract of Dioscorea officinalis alone is 27.0%, and the damage length during vertical combustion is 12.5 cm. Although it also meets the B1-level flame retardant performance requirements of my country's "Flame-retardant Decorative Fabrics", its limiting oxygen The index remains low. However, the limit oxygen index of silk fabrics treated with Dioscorea officinalis extract and polypropyleneimide dendrimer is as high as 30.6-30.8%, and the damage length during vertical combustion is 9.5-11.0cm, all of which meet the requirements of my country's "Flame Retardant Decorative Fabrics". Medium B1 flame retardant performance requirements, and the limiting oxygen index is higher, with better flame retardant performance; in addition, even after 20 repeated washings, its limiting oxygen index is still more than 30%, and the damage length during vertical combustion is still Less than 11cm, it can still meet the B1 level flame retardant performance requirements in my country's "Flame Retardant Decorative Fabrics", indicating that the flame retardant silk fabric prepared by the method of the present invention has good washing durability of the flame retardant function.

The above examples show that the silk fabrics treated by the combination of diospyrosa oleifera extract and polypropyleneimine dendrimers have good durability and flame retardant function.

The principle of the present application is: using the immersion adsorption method to make the condensed tannins in the Dioscorea sativa extract adsorbed on the silk fabric, and then using the immersion adsorption method to make the polypropylene imine dendrimer adsorbed on the silk fabric, at a certain temperature and Under weak alkaline conditions, condensed tannins and polypropyleneimine dendrimers undergo condensation and cross-linking reactions on silk fabrics, thereby forming a three-dimensional three-dimensional network structure that is insoluble in water. The existence of this cross-linked structure makes the silk fabric have a strong char-forming ability during combustion, and the formed carbon plays the role of heat insulation and oxygen insulation, thereby improving the flame retardant performance of the silk fabric.

The Dioscorea dioica extract used in the invention is safe and non-toxic, the polypropyleneimine dendrimer has many reactive points, and the condensed tannin and the polypropyleneimine dendrimer in the Dioscorea officinalis extract can be rapidly generated under weak alkaline conditions Condensation and cross-linking reaction, the cross-linked product can be well combined with silk fiber, ensuring the washing durability of flame retardant function; the cross-linked product of condensed tannin and polypropyleneimine dendrimer has good high temperature stability and The carbon-forming ability enables the silk fabric to have a strong carbon-forming ability during combustion; the process of the invention is simple, the operation is convenient, the finished silk fabric has excellent flame retardant effect and good durability, and can also realize dyeing and flame retardant finishing. one-step processing.

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims (7)

1. The method for preparing the flame-retardant silk is characterized by comprising the following steps of:

s1, immersing silk into the dioscorea cirrhosa extracting solution, heating to 75-90 ℃ for treatment, and obtaining silk fabric modified by condensed tannin;

s2, immersing the silk fabric modified by the condensed tannin into a polypropylene imine dendrimer solution with the pH value of 8-9.5 and the concentration of 5-15g/L, and heating to 55-70 ℃ for treatment to obtain the flame-retardant silk.

2. The method for preparing flame-retardant silk according to claim 1, wherein the step S1 further comprises preparing the dioscorea cirrhosa liquid extract, and the method comprises the following steps: placing rhizoma Dioscoreae Cirrhosae tuber at weight ratio of 15/100-30/100 in water, pulping, adjusting pH of the pulp to 8, heating to 85-95 deg.C, treating for 50-80min, and filtering to obtain rhizoma Dioscoreae Cirrhosae extractive solution.

3. The method for preparing flame-retardant silk according to claim 1, wherein the heating treatment time in the step S1 is 70-120 min.

4. The method for preparing flame-retardant silk according to claim 1, wherein the heating treatment time in step S2 is 30-40 min.

5. The method for preparing flame-retardant silk according to claim 1, wherein the polypropylene imine dendrimer is a second generation polypropylene imine dendrimer or a third generation polypropylene imine dendrimer.

6. Flame-retardant silk produced according to the method of any one of claims 1 to 5.

7. Use of the flame retardant silk according to claim 6 in textile applications.