Preparation method of flame-retardant carpet

Abstract

The invention provides a preparation method of a flame-retardant carpet, and belongs to the field of carpets.The preparation method comprises the steps of cotton fiber pretreatment, modified beta-cyclodextrin preparation, flame-retardant modified cotton fiber preparation and finished product manufacturing, and the method for preparing the flame-retardant modified cotton fiber comprises the steps that alkaline cotton fiber, maleic anhydride and a modified beta-cyclodextrin solution are evenly mixed; reacting in a closed environment at 140-160 DEG C for 2-3 hours, cooling to room temperature, washing with deionized water, and drying to constant weight at 35-45 DEG C to obtain flame-retardant modified cotton fiber; the flame-retardant carpet has the advantages that the flame-retardant effect is good, the limit oxygen index is 32.7-34.2%, the vertical combustion damage length is 45.7-48.5 mm, the washing resistance effect is good, the limit oxygen index is 27.2-29.1% and is larger than 27% after 40-degree washing, and the flame-retardant carpet belongs to a flame-retardant material.

Description

Technical Field

[0001] The invention belongs to the field of carpets, and in particular relates to a method for preparing a flame-retardant carpet. Background Art

[0002] As people's requirements for quality of life and taste for home decoration improve, carpets are loved by consumers for their elegance, comfort, dustproofness and soundproofing. The demand for carpets in residences, hotels, stadiums, exhibition halls, vehicles, ships, airplanes and other places continues to increase, driving the sustained growth of the carpet market. However, carpet raw materials are mostly wool, cotton, linen, silk, nylon, polypropylene, polyester, acrylic and other materials, which are mostly flammable. Every year, many fires are caused by carpet fires. Therefore, flame-retardant carpets have become mainstream. Compared with natural carpets, the flame-retardant technology of artificial carpets such as nylon, polypropylene, polyester and acrylic is relatively mature.

[0003] However, as people become more aware of their health and environmental protection, more and more people choose natural carpets. Pure cotton carpets have many advantages over wool carpets, such as good air permeability, good skin-friendliness, and good environmental performance. At the same time, they are cheaper than wool carpets and are favored by many middle-income families.

[0004] However, the flame retardancy of pure cotton carpets is low. Soaking the carpet raw materials in flame retardants to allow the flame retardants to penetrate into the carpet raw materials is the current method to improve the flame retardancy of pure cotton carpets. However, most flame retardants are combined with carpets through hydrogen bonds, van der Waals forces or intermolecular forces. During daily use and cleaning, the flame retardants will cause them to fall off, reducing the flame retardancy. At the same time, flame retardants will also affect the softness and breathability of pure cotton carpets.

[0005] Patent CN103361968A discloses a method for preparing flame-retardant pure cotton fabrics. By immersing the pure cotton fabrics in a prepared flame-retardant solution, the fabrics have high flame-retardant properties. However, the flame retardant components in the patent are magnesium hydroxide, zinc borate, and ammonium hydrogen phosphate. The combination of the flame retardant and the pure cotton fabric is not strong, and the flame retardant effect is poor. At the same time, ammonium hydrogen phosphate is acidic in the solution, which will destroy the fiber structure of the pure cotton fabric and affect its softness and breathability.

[0006] Patent CN108425245A discloses a method for preparing flame-retardant cotton fibers, in which a mixed cross-linking agent is used to combine cotton fibers with microcapsules containing expanded graphite to obtain flame-retardant cotton fibers. However, in this method, a large amount of microcapsules is added, reaching 30 wt% to 40 wt%, resulting in a serious decrease in multiple properties of the modified cotton fibers. At the same time, the microcapsules are very easy to fall off and break during the washing process, resulting in the loss of flame retardants and poor flame retardant durability. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a method for preparing a flame-retardant carpet to achieve the following invention objectives: to provide a method for grafting a flame retardant into cotton fibers, wherein the flame-retardant carpet prepared by the method has good flame retardant effect, good flame retardant adhesion, and high water washability.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for preparing a flame retardant carpet comprises the following steps: 1. Cotton pretreatment After cotton is ginned, cleaned and combed, the obtained cotton fiber is washed in an ethanol solution for 8 to 12 minutes to remove impurities, then washed with deionized water, and then soaked in a NaOH solution for 10 to 20 minutes, and then placed in an oven at 65 to 75° C. to dry to constant weight, thereby obtaining alkaline cotton fiber; The mass fraction of the ethanol solution is 60-80%; The mass fraction of the NaOH solution is 4-6%.

[0009] 2. Preparation of modified β-cyclodextrin β-cyclodextrin and modified ammonium polyphosphate are stirred and mixed at 80-120°C for 25-35 minutes, then a cross-linking agent H3BO3 is added, the temperature is raised to 120-135°C, the reaction is performed for 1.5-2.5 hours, the mixture is cooled to room temperature, and then anhydrous ethanol is added, the mixture is stirred evenly, and then the mixture is allowed to stand for 3-4 hours, and the precipitate is dried in an oven at 50-70°C to a constant weight to obtain modified β-cyclodextrin; The mass ratio of the β-cyclodextrin, modified ammonium polyphosphate, H3BO3 and anhydrous ethanol is 0.8-1.2: 9-11: 0.13-0.19: 10-12; The preparation method of the modified ammonium polyphosphate is as follows: adding silane coupling agent γ-aminopropyltrimethoxysilane to deionized water, hydrolyzing for 45 to 55 minutes at a stirring rate of 30 to 50 r / min, then adding ammonium polyphosphate, reacting at 40 to 60° C. for 0.8 to 1.2 hours, then heating to 110 to 130° C., continuing to react for 2 to 3 hours, then filtering, washing the filter cake with anhydrous ethanol for 2 to 4 times, drying at 55 to 65° C. for 12 to 18 hours, and crushing into powder with a particle size of 0.06 to 0.3 mm to obtain the modified ammonium polyphosphate; The mass ratio of the γ-aminopropyltrimethoxysilane, ammonium polyphosphate and deionized water is 15-19:950-970:50-70; The degree of polymerization of the ammonium polyphosphate is 80-120.

[0010] 3. Preparation of flame retardant modified cotton fiber The alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution are uniformly mixed, reacted at 140-160° C. in a closed environment for 2-3 hours, cooled to room temperature, washed with deionized water, and dried at 35-45° C. to constant weight to obtain flame-retardant modified cotton fiber; The mass ratio of the alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution is 20-40:0.2-0.4:41-43; The mass fraction of the β-cyclodextrin solution is 8-12%.

[0011] 4. Finished product manufacturing The flame-retardant modified cotton fibers are combed to make them straight and parallel, and then spun into yarns with a diameter of 0.6 to 1 mm. The yarns are fixed on a loom and a double-layer weaving method is adopted to obtain a finished flame-retardant carpet. The tex twist coefficient of the yarn is 300-400; The flame-retardant carpet has a warp density of 180 to 240 strands / cm, a weft density of 460 to 530 strands / cm, and a pile height of 15 to 20 mm.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. In the preparation method of modified β-cyclodextrin, the silane coupling agent γ-aminopropyltrimethoxysilane is hydrolyzed to obtain silanol, and the silanol hydroxyl groups of the silanol are adsorbed on the surface of ammonium polyphosphate, and undergo a dihydroxyl dehydration condensation reaction with the hydroxyl groups on the surface of the ammonium polyphosphate to form a stable chemical bond to obtain modified ammonium polyphosphate, and H3BO3 undergoes an esterification reaction with the hydroxyl groups on the surface of β-cyclodextrin and the modified ammonium polyphosphate to obtain modified β-cyclodextrin. When the carpet burns, the modified ammonium polyphosphate decomposes, and the generated SiO2 has high thermal stability and will be deposited on the surface of the carpet, isolating the air and having a flame retardant effect; at the same time, the phosphate compound layer and the silicate layer formed at high temperature can complement each other to form a more stable and dense protective layer, which can more effectively prevent the entry of oxygen and the release of combustible gas.

[0013] 2. In the preparation process of the flame-retardant carpet of the present invention, the cotton fiber is flame-retardantly modified, and maleic anhydride can undergo esterification reaction with modified β-cyclodextrin and the hydroxyl groups on the alkaline cotton fiber. The reaction conditions are mild to form stable covalent bonds. In the flame-retardant carpet prepared from the flame-retardant modified cotton fiber, the flame retardant is not easy to fall off, the water resistance is strong, and the flame retardant effect is good.

[0014] 3. The flame-retardant carpet of the present invention has good flame-retardant effect, and the limiting oxygen index is 32.7-34.2%. In the vertical combustion performance test, the damaged length is 45.7-48.5 mm. When leaving the ignition source, the flame-retardant carpet is extinguished immediately, and the afterflaming time and smoldering time are both 0. It has good water-washing resistance. After washing for 40 times, the limiting oxygen index is 27.2-29.1%, which is greater than 27%, and is a flame-retardant material. DETAILED DESCRIPTION

[0015] Example 1 A method for preparing a flame retardant carpet comprises the following steps: 1. Cotton pretreatment After cotton is ginned, cleaned and combed, the obtained cotton fiber is washed in an ethanol solution for 10 minutes to remove impurities, then washed with deionized water, and then soaked in a NaOH solution for 15 minutes, and then placed in an oven at 70°C to dry to constant weight to obtain alkaline cotton fiber; The mass fraction of the ethanol solution is 70%; The mass fraction of the NaOH solution is 5%.

[0016] 2. Preparation of modified β-cyclodextrin β-cyclodextrin and modified ammonium polyphosphate were stirred and mixed at 100°C for 30 minutes, and then a cross-linking agent H3BO3 was added, and the temperature was raised to 130°C, and the mixture was reacted for 2 hours, and then cooled to room temperature, and then added to anhydrous ethanol, stirred evenly, and then allowed to stand for 3.5 hours, and the precipitate was dried in an oven at 60°C to constant weight to obtain modified β-cyclodextrin; The mass ratio of the β-cyclodextrin, modified ammonium polyphosphate, H3BO3 and anhydrous ethanol is 1:10:0.16:11; The preparation method of the modified ammonium polyphosphate is as follows: adding silane coupling agent γ-aminopropyltrimethoxysilane to deionized water, hydrolyzing for 50 minutes at a stirring rate of 40 r / min, then adding ammonium polyphosphate, reacting at 50° C. for 1 hour, heating to 120° C., continuing to react for 2.5 hours, filtering, washing the filter cake with anhydrous ethanol for 3 times, then drying at 60° C. for 15 hours, and crushing into powder with a particle size of 0.1 to 0.2 mm to obtain the modified ammonium polyphosphate; The mass ratio of γ-aminopropyltrimethoxysilane, ammonium polyphosphate and deionized water is 17:960:60; The degree of polymerization of the ammonium polyphosphate is 100.

[0017] 3. Preparation of flame retardant modified cotton fiber The alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution were uniformly mixed, reacted at 150°C in a closed environment for 2.5 hours, cooled to room temperature, washed with deionized water, and dried at 40°C to constant weight to obtain flame-retardant modified cotton fiber; The mass ratio of the alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution is 30:0.3:42; The mass fraction of the modified β-cyclodextrin solution is 10%.

[0018] 4. Finished product manufacturing The flame-retardant modified cotton fibers are combed to make them straight and parallel, and then spun into yarns with a diameter of 0.8 mm. The yarns are fixed on a loom and a double-layer weaving method is adopted to obtain a finished flame-retardant carpet. The flame retardant carpet has a warp density of 200 strands / cm, a weft density of 500 strands / cm, and a pile height of 18 mm.

[0019] Example 2 A method for preparing a flame retardant carpet comprises the following steps: 1. Cotton pretreatment After cotton is ginned, cleaned and combed, the obtained cotton fiber is washed in an ethanol solution for 8 minutes to remove impurities, then washed with deionized water, and then soaked in a NaOH solution for 10 minutes, and then placed in an oven at 65°C to dry to constant weight to obtain alkaline cotton fiber; The mass fraction of the ethanol solution is 60%; The mass fraction of the NaOH solution is 4%.

[0020] 2. Preparation of modified β-cyclodextrin β-cyclodextrin and modified ammonium polyphosphate were stirred and mixed at 80°C for 25 minutes, and then a cross-linking agent H3BO3 was added, and the temperature was raised to 120°C. After reacting for 1.5 hours, the mixture was cooled to room temperature, and then added to anhydrous ethanol, stirred evenly, and then allowed to stand for 3 hours. The precipitate was dried in an oven at 50°C to constant weight to obtain modified β-cyclodextrin; The mass ratio of the β-cyclodextrin, modified ammonium polyphosphate, H3BO3 and anhydrous ethanol is 0.8:9:0.13:10; The preparation method of the modified ammonium polyphosphate is as follows: adding silane coupling agent γ-aminopropyltrimethoxysilane to deionized water, hydrolyzing for 45 minutes at a stirring rate of 30 r / min, then adding ammonium polyphosphate, reacting at 40° C. for 0.8 hours, heating to 110° C., continuing to react for 2 hours, filtering, washing the filter cake with anhydrous ethanol twice, then drying at 55° C. for 12 hours, and crushing into powder with a particle size of 0.06 to 0.1 mm to obtain the modified ammonium polyphosphate; The mass ratio of γ-aminopropyltrimethoxysilane, ammonium polyphosphate and deionized water is 15:950:50; The degree of polymerization of the ammonium polyphosphate is 80.

[0021] 3. Preparation of flame retardant modified cotton fiber The alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution were uniformly mixed, reacted at 140°C in a closed environment for 2 hours, cooled to room temperature, washed with deionized water, and dried at 35°C to constant weight to obtain flame-retardant modified cotton fiber; The mass ratio of the alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution is 20:0.2:41; The mass fraction of the modified β-cyclodextrin solution is 8%.

[0022] 4. Finished product manufacturing The flame-retardant modified cotton fibers are combed to make them straight and parallel, and then spun into yarns with a diameter of 0.6 mm. The yarns are fixed on a loom and a double-layer weaving method is adopted to obtain a finished flame-retardant carpet. The flame retardant carpet has a warp density of 180 strands / cm, a weft density of 460 strands / cm, and a pile height of 15 mm.

[0023] Example 3 A method for preparing a flame retardant carpet comprises the following steps: 1. Cotton pretreatment After cotton is ginned, cleaned and combed, the obtained cotton fiber is washed in an ethanol solution for 12 minutes to remove impurities, then washed with deionized water, and then soaked in a NaOH solution for 20 minutes, and then placed in an oven at 75°C to dry to constant weight to obtain alkaline cotton fiber; The mass fraction of the ethanol solution is 80%; The mass fraction of the NaOH solution is 6%.

[0024] 2. Preparation of modified β-cyclodextrin β-cyclodextrin and modified ammonium polyphosphate were stirred and mixed at 120°C for 35 minutes, and then a cross-linking agent H3BO3 was added, and the temperature was raised to 135°C. After reacting for 2.5 hours, the mixture was cooled to room temperature, and then added to anhydrous ethanol, stirred evenly, and then allowed to stand for 4 hours. The precipitate was dried in an oven at 70°C to constant weight to obtain modified β-cyclodextrin; The mass ratio of the β-cyclodextrin, modified ammonium polyphosphate, H3BO3 and anhydrous ethanol is 1.2:11:0.19:12; The preparation method of the modified ammonium polyphosphate is as follows: adding silane coupling agent γ-aminopropyltrimethoxysilane to deionized water, hydrolyzing for 55 minutes at a stirring rate of 50 r / min, then adding ammonium polyphosphate, reacting at 60° C. for 1.2 hours, heating to 130° C., continuing to react for 3 hours, filtering, washing the filter cake with anhydrous ethanol for 4 times, then drying at 65° C. for 18 hours, and crushing into powder with a particle size of 0.2 to 0.3 mm to obtain the modified ammonium polyphosphate; The mass ratio of γ-aminopropyltrimethoxysilane, ammonium polyphosphate and deionized water is 19:970:70; The degree of polymerization of the ammonium polyphosphate is 120.

[0025] 3. Preparation of flame retardant modified cotton fiber The alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution were uniformly mixed, reacted at 160°C in a closed environment for 3 hours, cooled to room temperature, washed with deionized water, and dried at 45°C to constant weight to obtain flame-retardant modified cotton fiber; The mass ratio of the alkaline cotton fiber, maleic anhydride and modified β-cyclodextrin solution is 40:0.3:43; The mass fraction of the modified β-cyclodextrin solution is 12%.

[0026] 4. Finished product manufacturing The flame-retardant modified cotton fibers are combed to make them straight and parallel, and then spun into yarns with a diameter of 1 mm. The yarns are fixed on a loom and a double-layer weaving method is adopted to obtain a finished flame-retardant carpet. The tex twist coefficient of the yarn is 400; The flame retardant carpet has a warp density of 240 strands / cm, a weft density of 530 strands / cm, and a pile height of 20 mm.

[0027] Comparative Example 1 On the basis of Example 1, the step of preparing modified ammonium polyphosphate is omitted, and the modified ammonium polyphosphate is replaced by ammonium polyphosphate, and the remaining steps are the same.

[0028] Comparative Example 2 On the basis of Example 1, step 2 is changed to prepare modified ammonium polyphosphate, and the specific steps are: adding silane coupling agent γ-aminopropyltrimethoxysilane to deionized water, hydrolyzing for 50 minutes at a stirring rate of 40r / min, then adding ammonium polyphosphate, reacting at 50°C for 1 hour, then heating to 120°C, continuing to react for 2.5 hours, and then filtering. The filter cake is washed 3 times with anhydrous ethanol, dried at 60°C for 15 hours, and crushed into a powder with a particle size of 0.1 to 0.2 mm to obtain modified ammonium polyphosphate; in step 3, modified β-cyclodextrin is changed to modified ammonium polyphosphate, and the specific steps are: evenly mixing alkaline cotton fiber with a modified ammonium polyphosphate solution with a mass fraction of 10%, and drying at 45°C to constant weight after 3 hours to obtain flame-retardant modified cotton fiber.

[0029] Test Example 1 The limiting oxygen index of the flame-retardant carpets prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was tested using GB / T5454-1997, and the vertical combustion performance (afterflame time, smoldering time, and damaged length) of the flame-retardant carpets prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was tested using GB / T5455-2014. The ignition time was 12 seconds. The test results are shown in Table 1.

[0030] Table 1

[0031] Test Example 2 The flame retardant carpets prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were washed 10, 20, 30 and 40 times respectively according to GB / T17596-1998, and then the limiting oxygen index of the flame retardant carpets was tested according to GB / T5454-1997. The test results are shown in Table 2.

[0032] Table 2

[0033] It can be seen from the above results that compared with Example 1, since Comparative Example 1 does not modify the ammonium polyphosphate, the flame retardant effect of the flame retardant carpet prepared by Comparative Example 1 is poor, the limiting oxygen index is significantly lower than that of Example 1, the damage length is longer than that of Example 1, and there is a smoldering time of 1s after the flame is extinguished; however, the combination mode of ammonium polyphosphate and alkaline cotton fiber in Comparative Example 1 is unchanged, so the relative reduction value of the limiting oxygen index after washing is not much different from that of Example 1, that is, the water washing effect is good.

[0034] Compared with Example 1, since Comparative Example 2 does not prepare modified β-cyclodextrin, the modified ammonium polyphosphate and alkaline cotton fiber are combined by immersion, so the combination is not strong and the water washing resistance is poor. After washing 20 times, the limiting oxygen index is lower than 27%. After washing 40 times, the limiting oxygen index is close to the limiting oxygen index (18%) of the pure cotton carpet raw material itself.

Claims

1. A method for preparing a flame retardant carpet, characterized in that: The preparation method includes cotton pretreatment, preparation of modified β-cyclodextrin, preparation of flame-retardant modified cotton fiber, and finished product manufacturing; The method for preparing modified β-cyclodextrin is as follows: β-cyclodextrin and modified ammonium polyphosphate are stirred and mixed at 80-120° C. for 25-35 minutes, H3BO3 is added, the temperature is raised to 120-135° C., the reaction is carried out for 1.5-2.5 hours, the mixture is cooled, and the mixture is allowed to stand in anhydrous ethanol, and the precipitate is dried to a constant weight to obtain modified β-cyclodextrin; The preparation method of the modified ammonium polyphosphate is as follows: adding silane coupling agent γ-aminopropyltrimethoxysilane to deionized water, stirring and hydrolyzing for 45 to 55 minutes, adding ammonium polyphosphate, reacting at 40 to 60° C. for 0.8 to 1.2 hours, then heating to 110 to 130° C., continuing to react for 2 to 3 hours, filtering, washing with anhydrous ethanol, drying, and crushing to obtain the modified ammonium polyphosphate; The method for preparing the flame retardant modified cotton fiber comprises: uniformly mixing alkaline cotton fiber, maleic anhydride and modified beta-cyclodextrin solution, reacting at 140-160° C. for 2-3 hours in a closed environment, cooling, washing and drying to obtain the flame retardant modified cotton fiber.

2. The method for preparing a flame retardant carpet according to claim 1, characterized in that: In the method for preparing modified β-cyclodextrin, the mass ratio of β-cyclodextrin, modified ammonium polyphosphate, H3BO3 and anhydrous ethanol is 0.8-1.2:9-11:0.13-0.19:10-12.

3. The method for preparing a flame retardant carpet according to claim 1, characterized in that: In the preparation method of the modified ammonium polyphosphate, the mass ratio of γ-aminopropyltrimethoxysilane, ammonium polyphosphate and deionized water is 15-19:950-970:50-70; and the polymerization degree of the ammonium polyphosphate is 80-120.

4. The method for preparing a flame retardant carpet according to claim 1, characterized in that: In the method for preparing flame-retardant modified cotton fiber, the mass ratio of basic cotton fiber, maleic anhydride and modified beta-cyclodextrin solution is 20-40:0.2-0.4:41-43; the mass fraction of the modified beta-cyclodextrin solution is 8-12%.

5. The method for preparing a flame retardant carpet according to claim 1, characterized in that: The cotton pretreatment method comprises washing the cotton fiber in an ethanol solution to remove impurities, then washing it with deionized water, and then soaking it in a NaOH solution for 10 to 20 minutes and drying it to obtain alkaline cotton fiber.

6. The method for preparing a flame retardant carpet according to claim 5, characterized in that: In the cotton pretreatment method, the mass fraction of the ethanol solution is 60-80%; the mass fraction of the NaOH solution is 4-6%.

7. The method for preparing a flame retardant carpet according to claim 1, characterized in that: The method for manufacturing the finished product is to comb the flame-retardant modified cotton fibers to make them straight and parallel, and then spin them into yarns with a diameter of 0.6 to 1 mm. The yarns are fixed on a loom and a double-layer weaving method is adopted to obtain a finished flame-retardant carpet.

8. The method for preparing a flame retardant carpet according to claim 7, characterized in that: In the method for manufacturing the finished product, the twist coefficient of the yarn is 300-400; the warp density of the flame-retardant carpet is 180-240 strands / cm, the weft density is 460-530 strands / cm, and the pile height is 15-20 mm.

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