Imidazolinone flame retardant, flame-retardant finishing liquid and fiber flame-retardant finishing process
Through the aqueous phase reaction between imidazolinone flame retardant and crosslinking agent, stable chemical bonds are formed, which solves the problem of insufficient flame retardant performance of cellulose fibers, and achieves an efficient and environmentally friendly flame retardant effect, with a significant increase in the limit oxygen index. Comply with the principle of green chemistry.
Patent Information
- Application Number
- CN202411267887.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2025-01-07
AI Technical Summary
The flame retardant properties of existing cellulose fibers are insufficient. Traditional flame retardants will release harmful gases and by-products during finishing, resulting in health and environmental risks and are difficult to meet increasingly stringent environmental regulations.
Imidazolinone flame retardant and crosslinking agent react in the aqueous phase, and by forming stable chemical bonds with cellulose fibers, the flame retardant performance is improved, and the flame retardant fiber is sorted through gentle process conditions to obtain efficient and environmentally friendly flame retardant fibers. Plain fiber.
It significantly improves the flame retardant performance and durability of cellulose fibers, with an extreme oxygen index of more than 33%, a mild process without harmful gases, complies with the principle of green chemistry, and a yield of more than 70%.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of textile engineering, and in particular to an imidazolinone flame retardant, a flame retardant finishing liquid and a fiber flame retardant finishing process. Background Art
[0002] Cellulose is the most widely distributed and abundant polysaccharide in nature, accounting for more than 50% of the carbon content in the plant kingdom. It has excellent properties such as light weight, biodegradability, low price, high modulus and high strength. These advantages make cellulose an important biomaterial and widely used in various industries and daily life fields. In particular, extracting cellulose from plants and functionalizing it through the regeneration process is an important way to effectively utilize natural resources and achieve sustainable development. Regenerated cellulose fiber is a kind of environmentally friendly fiber produced by physical modification using natural cellulose (such as cotton, linen, bamboo, straw, etc.) as raw materials. This type of cellulose fiber maintains the chemical structure of the original cellulose, retains many excellent properties of natural fibers, and has the unique advantages of regenerated fibers. Compared with synthetic chemical fibers, regenerated cellulose fibers have obvious advantages in hygroscopicity, breathability and wearing comfort, and their fabrics feel softer and silkier. Therefore, regenerated cellulose fibers play an increasingly important role in the modern textile industry and are widely used in the production of various types of clothing, home textiles and decorative fabrics.
[0003] Cellulose fiber faces a series of key challenges in the application process, especially its low limiting oxygen index (LOI) makes it extremely easy to burn under fire conditions, which significantly increases the risk of fire. Therefore, improving the flame retardant properties of regenerated cellulose fiber and its textiles has become the focus of current research. At present, the industrial flame retardant treatment of cellulose fiber mainly relies on halogen and phosphorus flame retardants. For example, the Proban ammonia fumigation process penetrates into the amorphous region of cellulose fiber through the pre-condensed body generated by tetrakis(hydroxymethyl)phosphine chloride and urea, forms a cross-linked polymer after ammonia treatment, and finally obtains the flame retardant effect through hydrogen peroxide oxidation. However, this process releases formaldehyde during the finishing process, and the treated fabric has a poor feel, which limits its wide application. Another typical treatment method is the Pyrovatex CP process, which uses N-hydroxymethyl-3-(dimethoxyphosphonyl) propionamide and a cross-linking agent to cross-link with cellulose under acid catalysis to prepare durable flame retardant cotton fabrics. However, the finishing agent in this process contains free formaldehyde, which will be gradually released during the storage and use of textiles, bringing potential health and environmental risks. Although the use of polyacids as cross-linking agents can reduce the emission of formaldehyde, it is still difficult to meet the increasingly stringent environmental regulations. In addition, traditional halogen-based flame retardants have been widely used in the flame retardant treatment of cellulose fibers due to their high efficiency, but the toxic and corrosive byproducts produced during use have led to their gradual withdrawal from the market, replaced by halogen-free flame retardants. Therefore, the development of cellulose fiber finishing agents and flame retardant processes with environmentally friendly and efficient flame retardant properties remains a key challenge in this field. Summary of the invention
[0004] In view of the deficiencies in the prior art, the present invention provides an imidazolinone flame retardant, the preparation of a flame retardant finishing liquid and a flame retardant finishing process for cellulose fibers.
[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention first provides a method for preparing an imidazolidinone flame retardant, comprising the following steps: 1) reacting 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone and phosphoric acid at 70-100° C. for 2-5 hours; 2) adding urea to the reaction system, reacting at 70-100° C. for 2-5 hours to obtain a reaction solution; 3) After the reaction liquid cools to room temperature, anhydrous ethanol is added to the reaction liquid, and the reaction liquid is placed at 0-4°C for crystallization, and then filtered, washed, and dried to obtain an imidazolinone flame retardant.
[0006] Furthermore, the molar ratio of the 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone, phosphoric acid and urea is 1:4~5:8~9.
[0007] Furthermore, the amount of anhydrous ethanol added in step 3) is 5-8 times the volume of the expected product, and the drying temperature is 60-100°C.
[0008] The present invention also provides a method for preparing a cellulose flame retardant finishing liquid: adding an imidazolidinone flame retardant and a cross-linking agent into water at a mass ratio of 5:1 to 5:2, and heating and dissolving them at 60 to 80°C.
[0009] Furthermore, the cross-linking agent is one or more of dichlorocyanamide, trichlorocyanamide, and guanidine carbonate.
[0010] The present invention also provides a cellulose fiber flame retardant finishing process, comprising the following steps: immersing the cellulose fiber in the cellulose flame retardant finishing liquid, soaking at 25-75°C for 15-120 minutes, then drying at 75-120°C for 30-90 minutes, and finally heating to 150-180°C and drying for 10-30 minutes to obtain flame retardant cellulose fiber.
[0011] Furthermore, the cellulose fiber raw material comes from natural cellulose fibers with spinnability, such as cotton fibers, hemp fibers, bamboo fibers, etc., and various types of regenerated cellulose fibers, such as viscose fibers, lyocell fibers, etc.
[0012] The present invention adopts the above technical solution and has the following beneficial effects: 1. The imidazolinone flame retardant of the present invention is rich in nitrogen and phosphorus elements, and can form stable chemical bonds with hydroxyl groups in cellulose fibers such as lyocell fibers, thereby significantly improving the flame retardant properties of the fibers and the durability of the flame retardant effect.
[0013] 2. The flame retardant finishing process of cellulose fiber of the present invention is carried out in water phase, the reaction conditions are mild, no harmful gas is generated, it complies with the principle of green chemistry, the yield is as high as over 70%, the limiting oxygen index of the obtained flame retardant cellulose fiber reaches over 33%, and the flame retardant performance of cellulose fiber is significantly improved. DETAILED DESCRIPTION
[0014] The present invention will be further described in detail below through specific examples. Example 1
[0015] 1. Preparation of imidazolinone flame retardants After mixing 1 mol of 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone, 5 mol of phosphoric acid and 100 mL of distilled water, heat to 100°C for reaction for 5 hours, then add 8 mol of urea to the mixture, and continue to react at 100°C for 5 hours. After the reaction is completed, the reaction solution is cooled to room temperature, and anhydrous ethanol equivalent to 5 times the volume of the expected product is slowly added. The mixture is placed in a refrigerator at 4°C for low-temperature crystallization to promote the precipitation of the target product. The precipitated solid is separated from the liquid by filtration, and the solid is further washed with anhydrous ethanol to remove residual impurities. The washed solid is placed in a 60°C forced air drying oven and dried to obtain an imidazolidinone flame retardant.
[0016] 2. Preparation of cellulose flame retardant finishing liquid 200 g of imidazolinone flame retardant and 60 g of dichlorocyanamide were added to 1000 ml of deionized water, and the mixture was heated to 80° C. until they were completely dissolved, thereby obtaining a cellulose flame retardant finishing liquid.
[0017] 3. Flame retardant finishing process of cellulose fiber 40 g of lyocell fiber was weighed and added into a cellulose flame retardant finishing liquid, and then immersed at 45° C. for 30 minutes, dried at 90° C. for 45 minutes, and then heated to 150° C. and dried for 30 minutes to obtain the flame retardant lyocell fiber.
[0018] The flame retardant treated and untreated lyocell fibers were tested according to GB / T 5454-1997 "Determination of Combustion Performance of Textiles - Oxygen Index Determination Method". The test results showed that the limiting oxygen index of the flame retardant treated lyocell fibers increased from 16.8% to 35.1%. Example 2
[0019] 1. Preparation of imidazolinone flame retardants After mixing 1 mol of 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone, 4 mol of phosphoric acid and 100 mL of distilled water, heat to 100 ° C for 4 hours, then add 8 mol of urea to the mixture, and continue to react at 100 ° C for 4 hours. After the reaction is completed, the reaction solution is cooled to room temperature, and anhydrous ethanol equivalent to 6 times the volume of the expected product is slowly added. The mixture is placed in a refrigerator at 4 ° C for low-temperature crystallization to promote the precipitation of the target product. The precipitated solid is separated from the liquid by filtration, and the solid is further washed with anhydrous ethanol to remove residual impurities. The washed solid is placed in a 60 ° C forced air drying oven and dried to obtain an imidazolidinone flame retardant.
[0020] 2. Preparation of cellulose flame retardant finishing liquid 200 g of imidazolinone flame retardant and 80 g of melamine were added to 1000 ml of deionized water, and the mixture was heated to 80° C. until they were completely dissolved, thereby obtaining a cellulose flame retardant finishing liquid.
[0021] 3. Flame retardant finishing process of cellulose fiber 40 g of lyocell fiber was weighed and added into cellulose flame retardant finishing liquid, immersed at 60° C. for 30 minutes, dried at 100° C. for 45 minutes, and then heated to 160° C. for drying for 20 minutes to obtain flame retardant lyocell fiber.
[0022] The flame retardant finished and unfinished lyocell fibers were tested according to GB / T 5454-1997 "Determination of Combustion Performance of Textiles - Oxygen Index Determination Method". The test results showed that the limiting oxygen index of the flame retardant finished lyocell fibers increased from 16.8% to 33.7%. Example 3
[0023] 1. Preparation of imidazolinone flame retardants After mixing 1 mol of 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone, 4 mol of phosphoric acid and 100 mL of distilled water, heat to 100 ° C for 4 hours, then add 8 mol of urea to the mixture, and continue to react at 100 ° C for 4 hours. After the reaction is completed, the reaction solution is cooled to room temperature, and anhydrous ethanol equivalent to 8 times the volume of the expected product is slowly added. The mixture is placed in a refrigerator at 3 ° C for low-temperature crystallization to promote the precipitation of the target product. The precipitated solid is separated from the liquid by filtration, and the solid is further washed with anhydrous ethanol to remove residual impurities. The washed solid is placed in a forced air drying at 80 ° C and dried to obtain an imidazolidinone flame retardant.
[0024] 2. Preparation of cellulose flame retardant finishing liquid 200 g of imidazolinone flame retardant and 60 g of dichlorocyanamide were added to 1000 ml of deionized water, and the mixture was heated to 60° C. until they were completely dissolved, thereby obtaining a cellulose flame retardant finishing liquid.
[0025] 3. Flame retardant finishing process of cellulose fiber 40 g of viscose fiber was weighed and added into the cellulose flame retardant finishing liquid, and then immersed at 60° C. for 30 minutes, dried at 120° C. for 30 minutes, and then heated to 170° C. for 15 minutes to obtain the flame retardant viscose fiber.
[0026] The flame retardant finished and unfinished viscose fibers were tested according to GB / T 5454-1997 "Determination of Combustion Performance of Textiles - Oxygen Index Determination Method". The test results showed that the limiting oxygen index of the flame retardant finished viscose fibers increased from 17.1% to 35.8%. Example 4
[0027] 1. Preparation of imidazolinone flame retardants After mixing 1 mol of 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone, 5 mol of phosphoric acid and 100 mL of distilled water, heat to 100°C and react for 3 hours. Then, add 8 mol of urea to the mixture and continue to react at 100°C for 3 hours. After the reaction is completed, the reaction solution is cooled to room temperature, and then anhydrous ethanol equivalent to 7 times the volume of the expected product is slowly added. The mixture is placed in a refrigerator at 1°C for low-temperature crystallization to promote the precipitation of the target product. The precipitated solid is separated from the liquid by filtration, and the solid is further washed with anhydrous ethanol to remove residual impurities. The washed solid is placed in a 75°C forced air drying oven and dried to obtain an imidazolidinone flame retardant.
[0028] 2. Preparation of cellulose flame retardant finishing liquid 200 g of imidazolinone flame retardant and 80 g of dichlorocyanamide were added to 1000 ml of deionized water, and the mixture was heated to 60° C. until they were completely dissolved, thereby obtaining a cellulose flame retardant finishing liquid.
[0029] 3. Flame retardant finishing process of cellulose fiber 40 g of cotton fiber was weighed and added into the cellulose flame retardant finishing liquid, soaked at 45° C. for 45 minutes, dried at 130° C. for 30 minutes, and then heated to 160° C. for 15 minutes to obtain flame retardant cotton fiber.
[0030] The flame retardant treated and untreated cotton fibers were tested according to GB / T 5454-1997 "Determination of Combustion Performance of Textiles - Oxygen Index Determination Method". The test results showed that the limiting oxygen index of the flame retardant treated cotton fibers increased from 17.1% to 34.3%.
[0031] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only some preferred embodiments of the present invention and cannot be understood as limiting the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made by technicians in this field within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A method for preparing an imidazolinone flame retardant, characterized in that: The steps include: 1) reacting 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone and phosphoric acid at 70-100° C. for 2-5 hours; 2) adding urea to the reaction system, reacting at 70-100° C. for 2-5 hours to obtain a reaction solution; 3) After the reaction liquid cools to room temperature, anhydrous ethanol is added to the reaction liquid, and the reaction liquid is placed at 0-4°C for crystallization, and then filtered, washed, and dried to obtain an imidazolinone flame retardant.
2. The method for preparing an imidazolinone flame retardant according to claim 1, characterized in that: The molar ratio of the 4,5-dihydroxy-1,3-dihydroxymethyl-2-imidazolidinone, phosphoric acid and urea is 1:4-5:8-9.
3. The method for preparing an imidazolinone flame retardant according to claim 1, characterized in that: The amount of anhydrous ethanol added in step 3) is 5-8 times the volume of the expected product, and the drying temperature is 60-100°C.
4. A method for preparing a cellulose flame retardant finishing liquid, characterized in that: The imidazolidinone flame retardant and the crosslinking agent obtained by the preparation method according to any one of claims 1 to 3 are added into water at a mass ratio of 5:1 to 5:2, and heated to dissolve at 60 to 80° C. to obtain a cellulose flame retardant finishing liquid.
5. The method for preparing a cellulose flame retardant finishing liquid according to claim 4, characterized in that: The cross-linking agent is one or more of dichlorocyanamide, trichlorocyanamide and guanidine carbonate.
6. A flame retardant finishing process for cellulose fibers, characterized in that: The cellulose fiber is immersed in the cellulose flame retardant finishing liquid obtained by the preparation method according to claim 4 or 5, immersed at 25-75° C. for 15-120 minutes, then dried at 75-120° C. for 30-90 minutes, and finally heated to 150-180° C. and dried for 10-30 minutes to obtain the flame retardant cellulose fiber.
7. A flame retardant finishing process for cellulose fibers according to claim 6, characterized in that: The cellulose fiber is natural cellulose fiber or regenerated cellulose fiber.
8. A flame retardant finishing process for cellulose fibers according to claim 6, characterized in that: The natural cellulose fibers are cotton fibers, hemp fibers or bamboo fibers, and the regenerated cellulose fibers are viscose fibers or lyocell fibers.