A preparation method of composite functional polyacrylonitrile pre-oxidized fiber fabric

Abstract

The present application provides a method for preparing a composite functional polyacrylonitrile preoxidized fiber fabric, which belongs to the technical field of functional textiles. After the diol is heated to be completely melted, a diisocyanate and a catalyst are added to react to obtain an isocyanate-terminated polyurethane prepolymer, which is recorded as component A, and a chain extender is mixed with a catalyst, which is recorded as component B. Component A and component B are evenly mixed, sprayed on the surface of the polyacrylonitrile preoxidized fiber fabric after padding pretreatment, reacted, and dried to obtain a composite functional polyacrylonitrile preoxidized fiber fabric. The present invention uses a mixture of component A and component B as a waterproofing agent, which itself does not contain water and organic solvents, has low drying energy consumption, small pollution, does not require emulsification treatment, and has excellent waterproof performance and durability.

Description

Technical Field

[0001] The present application relates to a method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric, and belongs to the technical field of functional textiles. Background Art

[0002] Polyacrylonitrile pre-oxidized fiber is widely used in flame-retardant fabrics, high-temperature resistant, acid- and alkali-resistant, and relatively inexpensive. However, there are certain structural defects inside the polyacrylonitrile fiber, and some new defects will continue to appear during the carbonization process due to high-temperature treatment, resulting in low fiber curl, weak cohesion, and decreased strength after carbonization, which directly affects the subsequent spinning process. In addition, when polyacrylonitrile pre-oxidized fiber is subjected to external forces during use and processing, carbonized fragments or residues often fall off, which seriously affects the promotion and application of the product.

[0003] Based on the problems existing in current flame-retardant fibers, this application aims to prepare a multifunctional fabric with both waterproof function and permanent flame-retardant properties to solve the defects of polyacrylonitrile pre-oxidized fibers in the application of textile field. Summary of the invention

[0004] In view of this, the present application provides a method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric, which imparts the provided fabric with both waterproofness and permanent flame retardancy, so as to solve the problems of existing polyacrylonitrile pre-oxidized flame retardant fibers such as low strength, poor wearing performance and poor waterproof effect.

[0005] Specifically, the present application is implemented through the following scheme:

[0006] A method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric, the steps are as follows:

[0007] (1) Preparation of waterproofing agent:

[0008] Component A: After the diol is heated until completely melted, diisocyanate is added, the temperature is raised to 60-80°C, the first catalyst is added, and the reaction is continued to obtain an isocyanate-terminated polyurethane prepolymer.

[0009] The molar ratio of the diol to the diisocyanate is 1:1-3.

[0010] Component B: a chain extender and a second catalyst, wherein the molar ratio of the chain extender to the diisocyanate is 1:2-4.

[0011] (2) Waterproof finishing:

[0012] Step 1: Mix component A and component B evenly, wherein the molar ratio of isocyanate group (-CNO) in component A to hydroxyl group (-OH) in component B in the mixture is 1:1.

[0013] Step 2: pretreating the polyacrylonitrile pre-oxidized fiber fabric by padding method, wherein the treatment liquid is a surfactant aqueous solution with a concentration of 20-30 g / L and a padding residue of 20-40%.

[0014] Step 3: Use a high-pressure nozzle to spray a uniform mixture of component A and component B on the surface of the fabric pretreated in step 2, and after the reaction is completed at 70-90° C., dry it to obtain a composite functional polyacrylonitrile pre-oxidized fiber fabric.

[0015] The above scheme first synthesizes component A and component B, and then mixes component A and component B to obtain a waterproofing agent. The waterproofing agent itself does not contain water and organic solvents, has low drying energy consumption, low pollution, does not require emulsification treatment, and has excellent waterproof performance and durability.

[0016] Further, as a preference:

[0017] In step one,

[0018] The diol is a composite of any one or more of polycaprolactone diol (PCL), polyether diol (PPG), polyether diol (PTMG), polytetramethylene glycol (PTMEG), and 1,12-dodecane diol. More preferably, the diol is a composite of polycaprolactone diol (such as PCL2000) and 1,12-dodecane diol, and the composite molar ratio of polycaprolactone diol to 1,12-dodecane diol is 1:0.1-0.3.

[0019] The diisocyanate includes one or a mixture of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), 1,4-cyclohexane diisocyanate (CHDI), and methylcyclohexane diisocyanate (HTDI). More preferably, the diisocyanate is a mixture of isophorone diisocyanate and dicyclohexylmethane-4,4'-diisocyanate, and the molar ratio of isophorone diisocyanate to dicyclohexylmethane-4,4'-diisocyanate is 1:2~5.

[0020] The first catalyst and the second catalyst are both dibutyltin dilaurate. More preferably, the first catalyst is added in an amount of 0.05-0.1% of the molar amount of the diisocyanate, and the second catalyst is added in an amount of 0.1-0.2% of the molar amount of the diisocyanate.

[0021] The chain extender is one of Span 60, Span 80, Span 40 and Span 20, preferably Span 60.

[0022] The surfactant is one or more of alkylphenol polyoxyethylene ether, high-carbon fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, and fatty acid methyl ester ethoxylate, preferably high-carbon fatty alcohol polyoxyethylene ether, and more preferably: fatty alcohol polyoxyethylene ether O-20.

[0023] In step 3, the drying temperature is 130-160°C, and the drying time is 3-5 min.

[0024] The finished composite functional polyacrylonitrile pre-oxidized fiber fabric obtained by the above scheme has excellent mechanical strength, waterproof effect and flame retardant properties, and has the following beneficial effects:

[0025] (1) The waterproof function of the finished fabric in this case is obtained by the direct reaction of the mixture of component A and component B on the fabric surface. It does not contain water and organic solvents, and the drying process has low energy consumption and little pollution. Compared with conventional polyurethane waterproofing agents, this preparation process does not require emulsification, which can not only save production costs, but also reduce transportation costs.

[0026] (2) Pre-treating the polyacrylonitrile pre-oxidized fiber fabric with a surfactant helps the waterproofing agent penetrate into the yarn and fiber. Combined with a polyurethane prepolymer and a chain extender with a smaller molecular weight, the prepared waterproofing agent can easily penetrate into the yarn and fiber during waterproof finishing, thereby improving the uniformity of the waterproofing effect and its durability against washing.

[0027] (3) The chain extender used is a sorbitol stearate substance, which contains three hydroxyl groups in its structure and can react with isocyanate-terminated polyurethane prepolymer to generate a polymer with a network structure, which can improve the waterproof performance and its durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a diagram showing the hydrophobic effect of the product of this application. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application clearer, the technical solutions of this application will be further described in detail below in combination with the specific cases in the embodiments of this application. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit the technical solutions of this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0032] Example 1

[0033] (1) Waterproofing agent:

[0034] Component A:

[0035] 0.1 mol of diol (the molar ratio of polycaprolactone diol PCL2000 and 1,12-dodecane diol is 1:0.2) was added to a 500 mL three-necked round-bottom flask, heated in an oven until completely melted, cooled to 50 °C, 0.35 mol of diisocyanate (the molar ratio of IPDI to HMDI is 1:3) was added, stirred at 500 r / min for 60 min, heated to 80 °C, 0.05 g of catalyst dibutyltin dilaurate and 10 mL of DMF were added, and the reaction was continued for 60 min to obtain an isocyanate-terminated polyurethane prepolymer.

[0036] Component B: 0.167 mol of chain extender Span 60 and 0.15 g of catalyst dibutyltin dilaurate were added.

[0037] (2) Waterproof finishing:

[0038] Step 1: Mix component A and component B evenly.

[0039] Step 2: pretreating the polyacrylonitrile pre-oxidized fiber fabric by padding method, wherein the treatment liquid is 20 g / L surfactant solution and the padding rate is 30%.

[0040] Step 3, using a high-pressure nozzle, spray the mixture obtained in step 1 evenly on the surface of the fabric pretreated in step 2, react at 80° C. for 10 minutes, heat to 150° C., and dry for 3 minutes.

[0041] Example 2

[0042] (1) Waterproofing agent

[0043] Component A: isocyanate-terminated polyurethane prepolymer.

[0044] In a 500 mL three-necked round-bottom flask, add 0.2 mol of diol (the molar ratio of polycaprolactone diol PCL2000 and 1,12-dodecane diol is 1:0.2), heat in an oven until completely melted, cool to 50°C, add 0.35 mol of diisocyanate (the molar ratio of IPDI to HMDI is 1:3), stir at 500 r / min for 60 min, heat to 80°C, add 0.05 g of catalyst dibutyltin dilaurate and 10 mL of DMF, and continue the reaction for 60 min to obtain an isocyanate-terminated polyurethane prepolymer.

[0045] Component B: 0.1 mol of chain extender Span 60 and 0.15 g of catalyst dibutyltin dilaurate.

[0046] (2) Waterproof finishing

[0047] Step 1: Mix component A and component B evenly.

[0048] Step 2: pretreating the polyacrylonitrile pre-oxidized fiber fabric by padding, wherein the treatment liquid is a 20 g / L surfactant aqueous solution and the padding rate is 30%.

[0049] Step 3, using a high-pressure nozzle to evenly spray the mixture of component A and component B on the surface of the pretreated polyacrylonitrile pre-oxidized fiber fabric, react at 80° C. for 10 minutes, heat to 150° C., and dry for 3 minutes.

[0050] Example 3

[0051] (1) Waterproofing agent

[0052] Component A: isocyanate-terminated polyurethane prepolymer.

[0053] In a 500 mL three-necked round-bottom flask, 0.3 mol of diol (the molar ratio of polycaprolactone diol PCL2000 and 1,12-dodecane diol is 1:0.2) was added, heated in an oven until completely melted, cooled to 50°C, 0.3 mol of diisocyanate (the molar ratio of IPDI to HMDI is 1:3) was added, stirred at 500 r / min for 60 min, heated to 80°C, 0.05 g of catalyst dibutyltin dilaurate and 10 mL of DMF were added, and the reaction was continued for 60 min to obtain an isocyanate-terminated polyurethane prepolymer.

[0054] Component B: 0.033 mol of chain extender Span 60 and 0.15 g of catalyst dibutyltin dilaurate.

[0055] (2) Waterproof finishing

[0056] Step 1: Mix component A and component B evenly.

[0057] Step 2: pretreating the polyacrylonitrile pre-oxidized fiber fabric by padding, wherein the treatment liquid is a 20 g / L surfactant aqueous solution and the padding rate is 30%.

[0058] Step 3, using a high-pressure nozzle to evenly spray the mixture of component A and component B on the surface of the pretreated polyacrylonitrile pre-oxidized fiber fabric, react at 80° C. for 10 minutes, heat to 150° C., and dry for 3 minutes.

[0059] Example 4

[0060] (1) Waterproofing agent

[0061] Component A: isocyanate-terminated polyurethane prepolymer.

[0062] In a 500 mL three-necked round-bottom flask, 0.2 mol of diol (the molar ratio of polycaprolactone diol PCL2000 and 1,12-dodecane diol is 1:0.2) was added, heated in an oven until completely melted, cooled to 50°C, 0.35 mol of diisocyanate (the molar ratio of IPDI to HMDI is 1:3) was added, stirred at 500 r / min for 60 min, heated to 80°C, 0.05 g of catalyst dibutyltin dilaurate and 10 mL of DMF were added, and the reaction was continued for 60 min to obtain an isocyanate-terminated polyurethane prepolymer.

[0063] Component B: 0.1 mol of chain extender Span 60 and 0.15 g of catalyst dibutyltin dilaurate.

[0064] (2) Waterproof finishing

[0065] Step 1: Mix component A and component B evenly.

[0066] Step 2: Use a high-pressure nozzle to evenly spray the mixture of component A and component B on the surface of the polyacrylonitrile pre-oxidized fiber fabric, react at 80° C. for 10 minutes, heat to 150° C., and dry for 3 minutes.

[0067] Example 5

[0068] (1) Waterproofing agent

[0069] Component A: isocyanate-terminated polyurethane prepolymer.

[0070] In a 500 mL three-necked round-bottom flask, add 0.2 mol of diol (the molar ratio of polycaprolactone diol PCL2000 and 1,12-dodecane diol is 1:0.2), heat in an oven until completely melted, cool to 50°C, add 0.35 mol of diisocyanate (the molar ratio of IPDI to HMDI is 1:3), stir at 500 r / min for 60 min, heat to 80°C, add 0.05 g of catalyst dibutyltin dilaurate and 10 mL of DMF, and continue the reaction for 60 min to obtain an isocyanate-terminated polyurethane prepolymer.

[0071] Component B: 0.1 mol of chain extender Span 60 and 0.15 g of catalyst dibutyltin dilaurate.

[0072] (2) Waterproof finishing

[0073] Step 1: Mix component A and component B evenly.

[0074] Step 2: pretreating the polyacrylonitrile pre-oxidized fiber fabric by padding, wherein the treatment liquid is a 20 g / L surfactant aqueous solution and the padding rate is 10%.

[0075] Step 3, using a high-pressure nozzle to evenly spray the mixture of component A and component B on the surface of the pretreated polyacrylonitrile pre-oxidized fiber fabric, react at 80° C. for 10 minutes, heat to 150° C., and dry for 3 minutes.

[0076] Example 6

[0077] (1) Waterproofing agent

[0078] Component A: isocyanate-terminated polyurethane prepolymer.

[0079] In a 500 mL three-necked round-bottom flask, 0.2 mol of diol (the molar ratio of polycaprolactone diol PCL2000 and 1,12-dodecane diol is 1:0.2) was added, heated in an oven until completely melted, cooled to 50°C, 0.35 mol of diisocyanate (the molar ratio of IPDI to HMDI is 1:3) was added, stirred at 500 r / min for 60 min, heated to 80°C, 0.05 g of catalyst dibutyltin dilaurate and 10 mL of DMF were added, and the reaction was continued for 60 min to obtain an isocyanate-terminated polyurethane prepolymer.

[0080] Component B: 0.1 mol of chain extender Span 60 and 0.15 g of catalyst dibutyltin dilaurate.

[0081] (2) Waterproof finishing

[0082] Step 1: Mix component A and component B evenly.

[0083] Step 2, pre-treating the polyacrylonitrile pre-oxidized fiber fabric by a padding method, wherein the treatment liquid is a 20 g / L surfactant aqueous solution and the padding rate is 50%.

[0084] Step 3, using a high-pressure nozzle to evenly spray the mixture of component A and component B on the surface of the pretreated polyacrylonitrile pre-oxidized fiber fabric, react at 80° C. for 10 minutes, heat to 150° C., and dry for 3 minutes.

[0085] The water-repellent effect, washing resistance, mechanical strength and flame retardant performance of the waterproof and flame-retardant composite functional polyacrylonitrile pre-oxidized fiber fabrics prepared in Examples 1 to 6 were analyzed. The washing method was carried out in accordance with the provisions of "GB / T 8629-2017 Household washing and drying procedures for textile testing"; the water-repellent effect was carried out in accordance with the provisions of "GB / T 4745-2012 Testing and evaluation of water-repellent performance of textiles"; the flame retardant performance was carried out in accordance with the provisions of "GB / T 5455-2014 Textile combustion performance Determination of vertical direction damage length, smoldering and afterflaming time"; the mechanical strength was carried out in accordance with the provisions of "GB / T 3923.1-2013 Textile fabric tensile properties Part 1: Determination of breaking strength and elongation at break (strip method)".

[0086] (1) Effect of diol and chain extender dosage on fabric properties

[0087] The amount of diol used is an important factor affecting the molecular weight of the polyurethane prepolymer, which affects the washing resistance of the waterproofing agent by affecting the film-forming property and film fastness of the waterproofing agent. The amount of Span 60 used is an important factor affecting the waterproofing performance. The test results of the water-repellent performance and washing resistance of the fabrics prepared in Example 1, Example 2, and Example 3 are shown in Table 1.

[0088] Table 1: Effect of the dosage of diol and Span 60 on the performance of fabric waterproofing agent

[0089] .

[0090] As can be seen from Table 1, when not washed, the fabric obtained in Example 2 has the best water staining grade (see Figure 1 ), the water level of the fabric prepared in Example 3 is the smallest. After washing 50 times, the water level of the fabrics prepared in Example 1 and Example 3 decreased significantly, while the water level of the fabric prepared in Example 2 hardly decreased. In addition, although the amount of Span used in Example 1 is more than that in Example 2, the water level is still less than that in Example 2. This is because when the amount of diol is small, the molecular chain of the polyurethane prepolymer is shorter, and the film-forming property of the waterproofing agent obtained after Span chain extension is poor, and it is easy to fall off during washing.

[0091] (2) Effect of pretreatment on fabric properties

[0092] The effects of pretreatment on the waterproof properties of fabrics are shown in Table 2.

[0093] Table 2: Effect of pretreatment on fabric properties

[0094] .

[0095] It can be seen from Table 2 that, before washing, the water-staining grade of the fabric prepared in Example 2 is the same as that of the fabric prepared in Example 4, but the washing resistance of the waterproof performance of the fabric prepared in Example 2 is better than that of the fabric prepared in Example 4. This is because the pretreatment helps the additive to spread on the surface of the fabric and penetrate into the yarn and fiber, thereby improving the washing resistance of the waterproof performance.

[0096] (3) Effect of rolling ratio on fabric performance

[0097] The results of the effect of rolling ratio on fabric properties are shown in Table 3.

[0098] Table 3: Effect of rolling ratio on fabric properties

[0099] .

[0100] It can be seen from Table 3 that before washing, the water-staining levels of the fabrics obtained in Example 2 and Example 5 were the same, and the water-staining level of the fabric obtained in Example 6 was lower. In addition, after washing 50 times, the water-staining level of the fabric obtained in Example 5 decreased slightly, and the water-staining level of the fabric obtained in Example 6 decreased the most. This is because, when the roll-off rate is small (such as in Example 5), the additive cannot penetrate into the yarn and fiber well; when the roll-off rate is large (such as in Example 6), due to the large water content of the fabric, the terminal isocyanate in the prepolymer can react with more water in the fabric, thereby reducing the waterproof performance of the fabric.

[0101] (4) Effect of waterproof finishing on flame retardancy and mechanical strength of fabrics

[0102] The effects of waterproof finishing on the flame retardancy and mechanical strength of fabrics were tested and compared. The results are shown in Table 4.

[0103] Table 4: Effect of waterproof finishing on flame retardancy and mechanical strength of fabrics

[0104] .

[0105] It can be seen from Table 4 that the waterproof finishing has no significant effect on the flame retardant properties of the polyacrylonitrile pre-oxidized fiber fabric, but can significantly improve the breaking strength of the fabric. This is because the network structure formed by the waterproof finishing can make up for the original defects of the fiber, thereby improving the breaking strength of the fabric.

[0106] The above-mentioned embodiments only express several feasible implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention, and the embodiments are not used to limit the scope of protection in the claims of the present invention. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and all equivalent implementations or changes that do not depart from the present invention should be included in the technology of the present invention.

Claims

1. A method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric, characterized in that: Here are the steps: Step 1: After the diol is heated until completely melted, diisocyanate is added, the temperature is raised to 60-80°C, a first catalyst is added, and the reaction is continued to obtain an isocyanate-terminated polyurethane prepolymer. The molar ratio of the diol to the diisocyanate is 1:1 to 3. The diol is a composite of any one or more of polycaprolactone diol PCL, polyether diol PPG, polyether diol PTMG, polytetrahydrofuran diol PTMEG, and 1,12-dodecane diol. The diisocyanate is one or a mixture of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,4-cyclohexane diisocyanate, and methylcyclohexane diisocyanate. Step 2: Add a chain extender and a second catalyst to the isocyanate-terminated polyurethane prepolymer obtained in step 1 and mix them evenly. The chain extender is one of Span 60, Span 80, Span 40, and Span 20. The molar ratio of the chain extender to the diisocyanate is 1:2-4, and the molar ratio of the isocyanate group to the hydroxyl group is 1:

1. Step 3, the polyacrylonitrile pre-oxidized fiber fabric is pre-treated by padding, the treatment liquid is a surfactant aqueous solution with a concentration of 20-30 g / L, and the padding residue is 20-40%; Step 4: spray the mixture obtained in step 2 on the surface of the fabric pretreated in step 3, and after the reaction is completed at 70-90° C., dry to obtain a composite functional polyacrylonitrile pre-oxidized fiber fabric.

2. The method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric according to claim 1, characterized in that: The diol is a composite of polycaprolactone diol PCL and 1,12-dodecane diol, and the composite molar ratio of polycaprolactone diol PCL to 1,12-dodecane diol is 1:0.1-0.

3.

3. The method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric according to claim 1, characterized in that: The diisocyanate is a mixture of isophorone diisocyanate and dicyclohexylmethane-4,4'-diisocyanate, and the molar ratio of isophorone diisocyanate to dicyclohexylmethane-4,4'-diisocyanate is 1:2-5.

4. The method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric according to claim 1, characterized in that: The first catalyst and the second catalyst are both dibutyltin dilaurate.

5. The method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric according to claim 4, characterized in that: The amount of the first catalyst added is 0.05-0.1% of the molar amount of the diisocyanate, and the amount of the second catalyst added is 0.1-0.2% of the molar amount of the diisocyanate.

6. The method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric according to claim 1, characterized in that: The surfactant is one or more of alkylphenol polyoxyethylene ether, high-carbon fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester, and fatty acid methyl ester ethoxylate.

7. The method for preparing a composite functional polyacrylonitrile pre-oxidized fiber fabric according to claim 1, characterized in that: The drying temperature is 130~160℃ and the drying time is 3~5 min.

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