Flame-retardant antibacterial finishing agent for cotton as well as preparation and application of flame-retardant antibacterial finishing agent

Abstract

The invention relates to the technical field of flame retardance and antibiosis, in particular to a flame-retardant and antibacterial finishing agent for cotton and preparation and application of the flame-retardant and antibacterial finishing agent. The preparation method comprises the following steps: firstly, dissolving polyhexamethylene guanidine hydrochloride and an epoxy compound, uniformly mixing, reacting, and post-treating to obtain a first intermediate; uniformly mixing the first intermediate with phosphoric acid in an inert atmosphere, and reacting to obtain a second intermediate; and finally, uniformly mixing the second intermediate with urea in an inert atmosphere, and reacting to obtain the flame-retardant antibacterial finishing agent for cotton. According to the flame-retardant antibacterial finishing agent for cotton provided by the invention, on the basis that the excellent bactericidal property of guanidine hydrochloride is fully exerted, the ammonium phosphate group enables cotton fabrics to be more easily dehydrated and carbonized, the cotton fabrics are endowed with excellent flame-retardant property, and the finishing agent has the advantage of washing resistance due to the formation of phosphate bonds.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardancy and antibacterial, and particularly relates to a flame retardant and antibacterial finishing agent for cotton, its preparation and application. Background Art

[0002] Among natural fibers, cotton fibers are widely used in the fields of the clothing industry, indoor furniture, and industrial manufacturing due to their comfortable breathability, health and environmental protection, excellent hygroscopicity, and ease of dyeing. However, due to its 18% LOI value, cotton fibers are flammable. In addition, the excellent hygroscopicity provides a comfortable environment for the reproduction of bacteria and microorganisms, which greatly limits the scope of application fields of cotton fibers. Therefore, it is necessary to carry out functional modification processing on cotton fabrics in terms of flame retardancy and antibacterial to improve their applicability in various fields.

[0003] With the continuous innovation of textile post-finishing technology, the research on flame retardant and antibacterial finishing agents for cotton is gradually attracting attention in the textile industry. However, current research is mostly limited to adding functional fillers to the matrix material or coating functional treatment agents on the material surface, resulting in most of the cotton finishing agents developed on the market being single-functional, either focusing on antibacterial performance or focusing on flame retardant performance.

[0004] In view of the above problems, it is crucial to provide a flame retardant and antibacterial finishing agent for cotton that can not only meet the antibacterial performance requirements of cotton fibers but also provide significant flame retardant function and excellent wash resistance. Summary of the Invention

[0005] To solve the above problems, the purpose of the present invention is to provide a flame retardant and antibacterial finishing agent for cotton, its preparation and application. The present invention first dissolves and mixes polyhexamethylene guanidine hydrochloride and an epoxy compound and then reacts, followed by post-treatment to obtain a first intermediate; then, in an inert atmosphere, the first intermediate and phosphoric acid are mixed and reacted to obtain a second intermediate; finally, in an inert atmosphere, the second intermediate and urea are mixed and reacted to obtain a flame retardant and antibacterial finishing agent for cotton. The flame retardant and antibacterial finishing agent for cotton provided by the present invention, while fully exerting the excellent bactericidal property of guanidine hydrochloride, enables cotton fabrics to be more easily dehydrated and carbonized due to its ammonium phosphate group, endowing the cotton fabrics with good flame retardant performance, and the formation of phosphoric acid ester bonds makes the finishing agent have the advantage of wash resistance; it breaks through the limitation of the single function of existing finishing agents on the market and obtains a highly efficient finishing agent with both flame retardant and antibacterial dual functions.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The first purpose of the present invention is to provide a flame retardant and antibacterial finishing agent for cotton, whose chemical structural formula is shown in formula (I):

[0008]

[0009] Among them, n is an integer from 5 to 30, and R is a substituent of the epoxy compound.

[0010] The second object of the present invention is to provide a preparation method of a flame retardant and antibacterial finishing agent for cotton, comprising the following steps:

[0011] (S1) Dissolve and mix polyhexamethylene guanidine hydrochloride and an epoxy compound, and then react, followed by post-treatment to obtain a first intermediate shown in formula (II);

[0012] (S2) Mix the first intermediate prepared in step (S1) with phosphoric acid and then react to obtain a second intermediate shown in formula (III);

[0013] (S3) Mix the second intermediate prepared in step (S2) with urea and then react to obtain a flame retardant and antibacterial finishing agent for cotton;

[0014] Among them, the reaction processes of step (S2) and step (S3) are carried out in an inert atmosphere;

[0015]

[0016] Among them, n is an integer from 5 to 30, and R is a substituent of the epoxy compound.

[0017] In an embodiment of the present invention, in step (S1), the epoxy compound is selected from one of glycidyl methacrylate, epichlorohydrin or allyl glycidyl ether;

[0018] The average molecular weight of the polyhexamethylene guanidine hydrochloride is 800 - 5000;

[0019] The polyhexamethylene guanidine hydrochloride and the epoxy compound are dissolved in dimethyl sulfoxide.

[0020] In an embodiment of the present invention, in step (S1), the molar ratio of polyhexamethylene guanidine hydrochloride to the epoxy compound is 1:1 - 3.

[0021] In an embodiment of the present invention, in step (S1), during the reaction, the temperature is 50 - 70 °C and the time is 48 - 96 h;

[0022] The post-treatment is to filter, wash and dry the reaction solution in sequence.

[0023] In an embodiment of the present invention, the washing reagent is selected from one of acetone or butanone;

[0024] During the drying process, the temperature is 50 °C and the time is 24 h.

[0025] In one embodiment of the present invention, in step (S2), the molar ratio of the first intermediate to phosphoric acid is 1:1 to 3.

[0026] In one embodiment of the present invention, in step (S2), during the reaction, the temperature is 80 to 160 °C and the time is 1 to 6 h.

[0027] In one embodiment of the present invention, in step (S3), the molar ratio of the second intermediate to urea is 1:2 to 6.

[0028] In one embodiment of the present invention, in step (S3), during the reaction, the temperature is 100 to 200 °C and the time is 1 to 4 h.

[0029] The third object of the present invention is to provide an application of a flame retardant and antibacterial finishing agent for cotton in flame retardancy and / or antibacterial of cotton fabrics.

[0030] In one embodiment of the present invention, the two-dip two-roll method is used for flame retardancy and / or antibacterial of cotton fabrics.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) In the flame retardant and antibacterial finishing agent for cotton provided by the present invention, guanidine hydrochloride has excellent antibacterial properties, and at the same time, the ammonium phosphate group makes the cotton fabric easier to dehydrate and carbonize, endowing the cotton fabric with good flame retardant properties.

[0033] (2) The flame retardant and antibacterial finishing agent for cotton provided by the present invention reacts chemically with cotton fibers, and the formation of phosphate ester bonds makes the finishing agent have excellent wash fastness.

[0034] (3) The flame retardant and antibacterial finishing agent for cotton provided by the present invention provides a new strategy for the further development of new multifunctional cotton fabrics. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is the infrared spectrum of the flame retardant and antibacterial finishing agent for cotton prepared in Example 1;

[0036] Figure 2 It is the thermostability analysis spectrum of the cotton fabric finished with the flame retardant and antibacterial finishing agent for cotton prepared in Example 1 and the original cotton fabric. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be described in detail below with reference to the accompanying drawings and specific examples.

[0038] In the following examples, unless otherwise specified, the reagents used are commercially available reagents, and the detection means and methods used are conventional detection means and methods in the art.

[0039] Example 1

[0040] This embodiment provides a preparation method of a flame retardant and antibacterial finishing agent for cotton, which is as follows:

[0041] (S1) 100 g (0.1 mol) of polyhexamethylene guanidine hydrochloride (average molecular weight 1000) was formulated into a 40 wt% polyhexamethylene guanidine hydrochloride solution, and 28.4 g (0.2 mol) of glycidyl methacrylate was added. The reaction was carried out at 55 °C with continuous stirring for 48 h, and then filtered, washed and dried to obtain the first intermediate;

[0042] Among them, the chemical structural formula of the first intermediate is shown as follows:

[0043]

[0044] n is an integer from 5 to 30;

[0045] (S2) 19.6 g of phosphoric acid was added to the first intermediate prepared in step (S1), and the reaction was carried out at 130 °C under nitrogen protection for 5 h to obtain the second intermediate;

[0046] Among them, the chemical structural formula of the second intermediate is shown as follows:

[0047]

[0048] n is an integer from 5 to 30;

[0049] (S3) 24 g of urea was added to the second intermediate prepared in step (S2), and the reaction was carried out at 150 °C under nitrogen protection for 2 h to prepare a flame retardant and antibacterial finishing agent for cotton (yield: 61%);

[0050] Among them, the chemical structural formula of the flame retardant and antibacterial finishing agent for cotton is shown as follows:

[0051]

[0052] n is an integer from 5 to 30.

[0053] The infrared spectrum of the flame retardant and antibacterial finishing agent for cotton prepared in this embodiment is as Figure 1 shown. It can be seen through Figure 1 that 3322 cm -1 and 3430 cm -1 are the stretching vibrations representing N-H; 1592 cm -1 and 1435 cm -1 correspond to the bending absorption of N-H and the in-plane bending vibration of N-H in the ammonium phosphate group; 1273 cm -1 , 1143 cm -1 , 1062 cm -1 , 890 cm -1The absorption peaks at [specific positions] successively reflect the asymmetric vibration of the PO2- group, the stretching vibration of the P=O double bond, the symmetric vibration of the P-O-P bridge connection, and the asymmetric vibration of the P-O-P bond; 710 cm -1 represents the characteristic peak of the bending vibration of O-P-O; 2500 - 3000 cm -1 is the characteristic peak of the Cl-H stretching vibration in guanidine hydrochloride; It can be proved that the obtained product coincides with the target product.

[0054] Example 2

[0055] This example provides a preparation method of a flame retardant and antibacterial finishing agent for cotton, which is as follows:

[0056] (S1) Prepare a 40 wt% polyhexamethylene guanidine hydrochloride solution with 200 g (0.1 mol) of polyhexamethylene guanidine hydrochloride (average molecular weight 2000), add 18.50 g (0.2 mol) of epichlorohydrin, and react at 70 °C with continuous stirring for 72 h. After filtration, washing, and drying, the first intermediate is obtained;

[0057] Among them, the chemical structural formula of the first intermediate is shown as follows:

[0058]

[0059] n is an integer from 5 to 30;

[0060] (S2) Add 19.6 g of phosphoric acid to the first intermediate prepared in step (S1), and react at 130 °C under nitrogen protection for 6 h to obtain the second intermediate;

[0061] Among them, the chemical structural formula of the second intermediate is shown as follows:

[0062]

[0063] n is an integer from 5 to 30;

[0064] (S3) Add 24 g of urea to the second intermediate prepared in step (S2), and react at 150 °C under nitrogen protection for 3 h to prepare a flame retardant and antibacterial finishing agent for cotton (yield is 69%);

[0065] Among them, the chemical structural formula of the flame retardant and antibacterial finishing agent for cotton is shown as follows:

[0066]

[0067] n is an integer from 5 to 30.

[0068] Example 3

[0069] This example provides a preparation method of a flame retardant and antibacterial finishing agent for cotton, which is as follows:

[0070] (S1) Dissolve 400 g (0.1 mol) of polyhexamethylene guanidine hydrochloride (average molecular weight 4000) to prepare a 40 wt% polyhexamethylene guanidine hydrochloride solution, add 22.83 g (0.2 mol) of allyl glycidyl ether, and react at 60 °C with continuous stirring for 75 h. Filter, wash, and dry to obtain the first intermediate;

[0071] Among them, the chemical structural formula of the first intermediate is shown as follows:

[0072]

[0073] n is an integer from 5 to 30;

[0074] (S2) Add 19.6 g of phosphoric acid to the first intermediate prepared in step (S1), and react at 140 °C under nitrogen protection for 6 h to obtain the second intermediate;

[0075] Among them, the chemical structural formula of the second intermediate is shown as follows:

[0076]

[0077] n is an integer from 5 to 30;

[0078] (S3) Add 24 g of urea to the second intermediate prepared in step (S2), and react at 150 °C under nitrogen protection for 2 h to prepare a flame retardant and antibacterial finishing agent for cotton (yield: 76%);

[0079] Among them, the chemical structural formula of the flame retardant and antibacterial finishing agent for cotton is shown as follows:

[0080]

[0081] n is an integer from 5 to 30.

[0082] Comparative Example 1

[0083] This comparative example provides a preparation method of a flame retardant and antibacterial finishing agent for cotton, which is as follows:

[0084] (S1) Dissolve 400 g (0.1 mol) of polyhexamethylene guanidine hydrochloride (average molecular weight 4000) to prepare a 40 wt% polyhexamethylene guanidine hydrochloride solution, add 34.24 g (0.3 mol) of allyl glycidyl ether, and react at 60 °C with continuous stirring for 75 h. Filter, wash, and dry to obtain the first intermediate;

[0085] (S2) Add 19.6 g of phosphoric acid to the first intermediate prepared in step (S1), and react at 140 °C under nitrogen protection for 6 h to obtain the second intermediate;

[0086] (S3) Add 24 g of urea to the second intermediate prepared in step (S2), and react for 2 h under nitrogen protection at 150 °C to prepare a flame retardant and antibacterial finishing agent for cotton (yield: 62%).

[0087] Comparative Example 2

[0088] This comparative example provides a method for preparing a flame retardant and antibacterial finishing agent for cotton, which is as follows:

[0089] (S1) Prepare a 40 wt% polyhexamethylene guanidine hydrochloride solution by dissolving 400 g (0.1 mol) of polyhexamethylene guanidine hydrochloride (average molecular weight 4000), add 11.41 g (0.1 mol) of allyl glycidyl ether, and react at 60 °C with continuous stirring for 75 h. Filter, wash, and dry to obtain the first intermediate;

[0090] (S2) Add 19.6 g of phosphoric acid to the first intermediate prepared in step (S1), and react at 140 °C under nitrogen protection for 6 h to obtain the second intermediate;

[0091] (S3) Add 24 g of urea to the second intermediate prepared in step (S2), and react at 150 °C under nitrogen protection for 2 h to prepare a flame retardant and antibacterial finishing agent for cotton (yield: 62%).

[0092] Comparative Example 3

[0093] This comparative example provides a method for preparing a flame retardant and antibacterial finishing agent for cotton, which is as follows:

[0094] (S1) Prepare a 40 wt% polyhexamethylene guanidine hydrochloride solution by dissolving 400 g (0.1 mol) of polyhexamethylene guanidine hydrochloride (average molecular weight 4000), add 22.83 g (0.2 mol) of allyl glycidyl ether, and react at 60 °C with continuous stirring for 75 h. Filter, wash, and dry to obtain the first intermediate;

[0095] (S2) Add 19.6 g of phosphoric acid to the first intermediate prepared in step (S1), and react at 140 °C under nitrogen protection for 6 h to obtain the second intermediate;

[0096] (S3) Add 15 g of urea to the second intermediate prepared in step (S2), and react at 150 °C under nitrogen protection for 2 h to prepare a flame retardant and antibacterial finishing agent for cotton (yield: 58%).

[0097] Comparative Example 4

[0098] This comparative example provides a method for preparing a flame retardant and antibacterial finishing agent for cotton, which is as follows:

[0099] (S1) Dissolve 400 g (0.1 mol) of polyhexamethylene guanidine hydrochloride (average molecular weight 4000) to prepare a 40 wt% polyhexamethylene guanidine hydrochloride solution, add 22.83 g (0.2 mol) of allyl glycidyl ether, and react at 60 °C with continuous stirring for 75 h. Filter, wash, and dry to obtain the first intermediate;

[0100] (S2) Add 19.6 g of phosphoric acid to the first intermediate prepared in step (S1), and react at 140 °C under nitrogen protection for 6 h to obtain the second intermediate;

[0101] (S3) Add 50 g of urea to the second intermediate prepared in step (S2), and react at 150 °C under nitrogen protection for 2 h to prepare a flame retardant and antibacterial finishing agent for cotton (yield: 64%);

[0102] Prepare an aqueous solution of 30 wt% with the flame retardant and antibacterial finishing agents for cotton prepared in Examples 1 - 3 and Comparative Examples 1 - 4, and add dicyandiamide (final concentration 7 wt%) and urea (final concentration 5 wt%) as a catalyst and a penetration aid respectively to the aqueous solution, and mix well to obtain the working solution;

[0103] According to a bath ratio of 1:20, immerse the cotton fabric in the working solution at 70 °C for 5 minutes, pad the fabric through two - immersion and two - rolling to a liquor - pick - up rate of 110%, then fix it in an oven. First, dry the moisture at 100 °C, then raise the oven temperature to 180 °C, and perform a heat - setting treatment on the dried fabric for 3 min. Test the limiting oxygen index of different flame retardants according to GB5454 - 85, and test the bactericidal performance of different antibacterial agents according to GB / T20944.1 - 2007.

[0104] Table 1 Flame retardant and antibacterial effects of cotton fabrics finished with different flame retardant and antibacterial agents

[0105]

[0106]

[0107] Remarks: Bactericidal test conditions: temperature 25 °C, pH 7, time 30 min; the inoculation amount of Escherichia coli for each sample is 5.78×10 7 CFU; the inoculation amount of Staphylococcus aureus for each sample is 7.58×10 8 CFU.

[0108] As can be seen from Table 1, for the cotton fabrics finished with the cotton flame retardant and antibacterial finishing agents prepared in Application Examples 1 to 3, under the condition of the same dosage, their limiting oxygen indices far exceed that of the cotton fabric itself. The larger the limiting oxygen index, the better the flame retardant performance of the flame retardant. After 30 water treatments, the cotton fabrics still have good flame retardant and antibacterial properties. From Application Examples 1 to 3, it can be seen that by changing the average molecular weight of polyhexamethylene guanidine hydrochloride, compared with Application Example 1, the limiting oxygen index decreases, but still has good flame retardant performance; at the same time, the bactericidal rates of both bacteria have been greatly improved, indicating that the higher the molecular weight, the more positive charges on the polymer chain, thus more closely adsorbed on the surface of bacteria, and then destroying the integrity of the cell membrane. From Application Example 3 and Comparative Examples 1 to 4, it can be seen that only when the reaction ratio is adjusted to a certain range can the flame retardant and antibacterial agent have good flame retardancy and antibacterial properties at the same time. In addition, the ammonium phosphate of the antibacterial flame retardant will also undergo an esterification reaction with the hydroxyl groups on the cotton fiber to form phosphate ester bonds, so that the flame retardant has certain water resistance.

[0109] The thermogravimetric analysis diagram of the cotton fabric (marked as "flame retardant and antibacterial cotton fabric") finished with the flame retardant and antibacterial finishing agent prepared in Application Example 1 is as Figure 2 shown. By Figure 2 observing, it can be found that the mass of the control cotton (untreated cotton fabric, original cotton fabric) begins to decrease rapidly from 340 °C, and T max is 409.3 °C. Compared with the original cotton, the cotton sample treated with the antibacterial finishing agent shows an earlier decomposition temperature, and its mass begins to decrease sharply at 106.4 °C, and the maximum pyrolysis temperature (T max ) is 314.5 °C. It shows that the phosphate groups attached to the surface of the antibacterial flame retardant cotton decompose into polyphosphoric acid or metaphosphoric acid at a lower temperature. This process not only significantly reduces the maximum thermal degradation rate, but also inhibits the formation of levoglucose and catalyzes the dehydration carbonization process of cotton fibers; the carbon layer formed thereby covers the surface of the cotton fibers, effectively blocking the further penetration of heat and oxygen, thus slowing down the subsequent decomposition of the cotton fibers. At 600 °C, the char residue rate of the untreated cotton fabric is only 11.57%, while for the cotton sample treated with the antibacterial flame retardant finishing agent, its char residue rate is greatly increased to 36.57%. This result clearly shows that the antibacterial flame retardant finishing agent significantly enhances the dehydration carbonization process of cotton fibers, indicating that the antibacterial flame retardant finishing agent has good flame retardant function.

[0110] The above description of the embodiments is provided to enable those of ordinary skill in the art to understand and practice the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art based on the explanation of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A flame retardant and antibacterial finishing agent for cotton, characterized in that, Its chemical structural formula is shown in formula (I): Wherein, n is an integer from 5 to 30, and R is a substituent of the epoxy compound.

2. A preparation method of the cotton flame retardant and antibacterial finishing agent as described in claim 1, characterized in that, It includes the following steps: (S1) Dissolve and mix polyhexamethylene guanidine hydrochloride and an epoxy compound and then react, and perform post-treatment to obtain a first intermediate shown in formula (II); (S2) Mix the first intermediate prepared in step (S1) and phosphoric acid and then react to obtain a second intermediate shown in formula (III); (S3) Mix the second intermediate prepared in step (S2) and urea and then react to obtain a flame retardant and antibacterial finishing agent for cotton; Wherein, the reaction processes of step (S2) and step (S3) are carried out in an inert atmosphere; Wherein, n is an integer from 5 to 30, and R is a substituent of the epoxy compound.

3. The preparation method of a cotton flame retardant and antibacterial finishing agent according to claim 2, characterized in that, In step (S1), the epoxy compound is selected from one of glycidyl methacrylate, epichlorohydrin or allyl glycidyl ether; The average molecular weight of the polyhexamethylene guanidine hydrochloride is 800 - 5000.

4. The preparation method of a cotton flame retardant and antibacterial finishing agent according to claim 2, characterized in that, In step (S1), the molar ratio of polyhexamethylene guanidine hydrochloride to the epoxy compound is 1:1 - 3.

5. The preparation method of a cotton flame retardant and antibacterial finishing agent according to claim 2, characterized in that, In step (S1), during the reaction process, the temperature is 50 - 70 °C and the time is 48 - 96 h; The post-treatment is to filter, wash and dry the reaction solution in sequence.

6. The preparation method of a cotton flame retardant and antibacterial finishing agent according to claim 2, characterized in that, In step (S2), the molar ratio of the first intermediate to phosphoric acid is 1:1 - 3.

7. The preparation method of a cotton flame retardant and antibacterial finishing agent according to claim 2, characterized in that, In step (S2), during the reaction process, the temperature is 80 - 160 °C and the time is 1 - 6 h.

8. The preparation method of a cotton flame retardant and antibacterial finishing agent according to claim 2, characterized in that, In step (S3), the molar ratio of the second intermediate to urea is 1:2 - 6.

9. The preparation method of a cotton flame retardant and antibacterial finishing agent according to claim 2, characterized in that, In step (S3), during the reaction process, the temperature is 100 - 200 °C and the time is 1 - 4 h.

10. Application of a flame retardant and antibacterial finishing agent for cotton as described in claim 1 in flame retardancy and / or antibacterial of cotton fabrics.

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