Preparation method for bio-based polyurethane elastic fiber

Abstract

The present invention relates to the field of the preparation of polyurethane elastic fibers, and relates to a preparation method for a bio-based polyurethane elastic fiber, comprising: preparing polyether polyol from sucrose, glycerol, dimethylamine and propylene oxide; adding a solvent, i.e., N,N-dimethylacetamide, and polyether polyol and polyisocyanate into a reaction tank, and adding p-Toluenesulfonyl semicarbazide and aluminum methylenebis(2,4-di-tert-butylphenoxy) phosphate to prepare a spinning solution; and subjecting the spinning solution to spinning and oil application by means of dry spinning technology to obtain the bio-based polyurethane elastic fiber. The present invention ensures that the properties of polyurethane elastic fibers do not deteriorate or are partially enhanced, while the cost and performance advantages are achieved.

Description

Method for preparing a bio-based polyurethane elastic fiber TECHNICAL FIELD

[0001] The present application relates to the field of polyurethane elastic fiber, in particular to a method for preparing a bio-based polyurethane elastic fiber. BACKGROUND

[0002] Polyurethane elastic fiber is a kind of block copolymer mainly composed of polyurethane, commonly known as spandex in China, and is one of the most widely used elastic fibers. Polyurethane elastic fiber has extraordinary stretching and recovery ability, and has the characteristics of high elasticity, low modulus, high hydrolysis resistance, etc., and is widely used in the clothing and textile industry. At present, there are many preparation methods of polyurethane elastic fiber on the market, for example, in the authorized announcement CN112410930B, a polyurethane elastic fiber with excellent dyeing performance and its preparation method are disclosed, the polyurethane elastic fiber comprises polyurethane and / or polyurethane urea and modified nylon resin, wherein the modified nylon resin accounts for 0.1-30% of the mass percentage of the polyurethane elastic fiber composite material; the polyurethane and / or polyurethane urea is obtained by reacting oligomer diol, diisocyanate and chain extender.

[0003] CN113774522B discloses a kind of high elongation high strength polyurethane elastic fiber and its preparation method, polyurethane prepolymer is obtained by reacting polyether diol, polyether ester diol and diisocyanate, then dissolved in polar solvent, chain extender and chain terminator are added to prepare polyurethane urea stock solution A; polyurethane prepolymer is obtained by reacting polyester diol, polyether ester diol and diisocyanate, then dissolved in polar solvent, chain extender and chain terminator are added to prepare polyurethane urea stock solution B; polyurethane urea stock solution A is used as skin layer material, polyurethane urea stock solution B is used as core layer material, through spinneret combination, a fiber with skin-core structure is prepared; the fiber with skin-core structure volatilizes polar solvent through high temperature duct, and is coated with oil agent, to obtain high elongation high strength polyurethane elastic fiber. By introducing aromatic polyester diol, the strength is improved, and by introducing high molecular weight polyether ester diol, the elongation at break is improved.

[0004] CN117127276A discloses a kind of bio-based spandex elastic fiber and its preparation method, bio-based spandex is introduced into spandex molecular chain by bio-based polyether polyol, wherein bio-based polyether polyol contains bio-based 1,3-propanediol unit structure. The bio-based spandex is reacted with polyurethane prepolymer containing bio-based and mixed amine to obtain a raw material containing polyurethane-urea polymer, and bio-based spandex elastic fiber is obtained by dry spinning.

[0005] Although there are many studies on the performance improvement of polyurethane elastic fiber at present, there are few reports on the preparation of bio-based polyurethane elastic fiber using green and environmentally friendly renewable raw materials. Biodegradable materials with environmental friendly characteristics have attracted great attention, and as traditional industry, spandex must accelerate the transformation and upgrading of green new technology and industry. Green and low-carbon bio-based spandex will be the trend of future spandex development. Polyol and isocyanate are two raw materials for synthesizing polyurethane, which are currently mainly derived from petroleum resources. With the depletion of petroleum resources and the aggravation of environmental problems, the preparation of polyurethane from green and renewable biomass resources has become one of the important directions of the development of China's strategic emerging material industry and biomass industry. Compared with petroleum-based polyurethane raw materials, bio-based polyurethane raw materials are less toxic, more abundant in source, lower in price, and more diverse in structure, which is conducive to the expansion of industrial production scale and the reduction of production cost, and can effectively improve the comprehensive performance of polyurethane materials. However, the use of biomass raw materials to prepare elastic fiber may have the problems of insufficient reaction or instability due to the performance difference between bio-based raw materials and petrochemical-based materials, or the performance of the prepared elastic fiber may be reduced and difficult to meet the use requirements, or the cost is high.

[0006] Based on the above problems, the applicant has studied the above problems and produced the present case. Technical problem

[0007] The purpose of the present application is to provide a preparation method of bio-based polyurethane elastic fiber which can guarantee no performance reduction or partial function improvement, and can balance the cost and performance advantages. Technical solution

[0008] In order to achieve the above purpose, the present application adopts the following technical scheme: a preparation method of bio-based polyurethane elastic fiber, comprising the following steps: step A: adding sucrose and glycerol according to the molar ratio of 1-2:1 into a reaction kettle, adding dimethylamine, the addition amount of dimethylamine is 30-50% of the total amount of dimethylamine (in this application, dimethylamine is added twice, and the total amount of dimethylamine here is the total addition amount of dimethylamine twice), under the condition of vacuumizing, the temperature is raised to 85-95℃, the reaction time is 1-1.5h, and the speed of adding propylene oxide is 5-10mL.min -1 The addition amount of propylene oxide is 10-30% of the total amount of propylene oxide (in this application, propylene oxide is added twice, and the total amount of propylene oxide here is the total addition amount of propylene oxide twice), wherein the total amount of propylene oxide is 2-3 times the mass of sucrose; the temperature is kept at 90-100℃, vacuum aging is carried out for 2-3h, then the temperature is raised to 120-130℃, the pressure is kept constant at 0.25-10.3MPa, the remaining dimethylamine is added, and the speed of adding propylene oxide is 5-10mL.min -1The remaining propylene oxide is added at a speed, and the reaction continues until the pressure in the reactor becomes negative, the reaction is stopped, and the aging continues for 2-3 h, the temperature is controlled at 80-90℃, 50-60 g of oxalic acid aqueous solution with a mass concentration of 11%-12% is added, and a mixture of magnesium silicate and aluminum silicate is added, the mass concentration of the mixture of magnesium silicate and aluminum silicate is 0.1-0.2% of the total amount of sucrose, glycerol and propylene oxide, the mass concentration of dimethylamine is 1-3% of the total amount of sucrose, glycerol and propylene oxide, then stirring for 20-30 min, filtering, vacuum dehydration, and drying at 60-70℃, to obtain the polyether polyol; step B: adding a solvent N,N-dimethylacetamide, the polyether polyol of step A and a polyisocyanate into a reactor, the mass concentration of the solvent is 45%-65%, the molar ratio of the polyether polyol and the polyisocyanate compound is 1:1.5-1:2, the reaction temperature is 45-60℃, and the reaction is carried out in a nitrogen atmosphere for 2-3 h to obtain a prepolymer solution; when the prepolymer solution is cooled to 10-20℃, a mixed amine solution is added to carry out chain extension reaction and chain termination reaction to form a polyurethane solution, the mass fraction of the mixed amine solution in the polyurethane solution is 5-10%; 0.05-0.08% of p-toluenesulfonyl urea of the mass concentration of the polyurethane solution is added, stirring is carried out until the mixture is uniform, 0.1-0.5% of aluminum methylene bis(2,4-di-t-butylphenoxy) phosphate of the mass concentration of the polyurethane solution is added, and the mixture is aged for 20-24 h to obtain a spinning dope after degassing; the spinning dope is spun through a dry spinning technology, and oiling is carried out to obtain a bio-based polyurethane elastic fiber.

[0009] As a preferred mode of the present application, in the mixture of magnesium silicate and aluminum silicate, the mass ratio of magnesium silicate to aluminum silicate is 1:1.

[0010] As a preferred mode of the present application, the polyisocyanate is one or a mixture of two of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate.

[0011] As a preferred mode of the present application, the amine solution is prepared by mixing ethylenediamine, propylenediamine and diethylamine in a molar ratio of 1:1:1 and dissolving them in dimethylacetamide.

[0012] As a preferred mode of the present application, the molecular weight of the polyether polyol is 1500-3000. Advantages

[0013] The degree of dispersion and dissolution of sucrose is one of the key points of the application, and the incomplete reaction of sucrose, the presence of a large number of monomers and the like directly affect the quality of the polyether polyol, the application uses sucrose and glycerol as the starting agent, which is beneficial to the dispersion and dissolution of sucrose, and the addition of glycerol can improve the elasticity of the bio-based polyurethane fiber. The selection of the chemical foaming agent in the preparation process of the bio-based polyurethane elastic fiber is also one of the key points of the application, and the use of the foaming agent p-toluenesulfonyl urea with a high decomposition temperature can prevent the decomposition of the foaming agent during the curing process of the polyurethane stock solution, generate bubbles and affect the production process. The application uses sucrose as the raw material to prepare polyether polyol, and then synthesizes polyurethane with polyisocyanate, develops green and environmentally friendly and degradable polyurethane elastic fiber from the source, solves the technical problems of insufficient reaction or instability caused by the performance difference between bio-based raw materials and petrochemical materials through process control, ensures that the performance of the polyurethane elastic fiber is not reduced or partially improved, and at the same time, the cost and performance advantages are considered. BRIEF DESCRIPTION OF DRAWINGS

[0014] Enter the drawing description paragraph here. BEST MODE FOR CARRYING OUT THE INVENTION

[0015] Enter the best mode for carrying out the invention description paragraph here. EMBODIMENTS OF THE INVENTION

[0016] In order to better understand the technical scheme of the application, the following embodiments are described in more detail.

[0017] Case 1.

[0018] Sucrose 342g, glycerol 92g, dimethylamine 4.38g were added to the reaction kettle, the air was replaced with nitrogen for 5 times, then the temperature was raised to 85℃ under vacuum, and the reaction was carried out for 1.5h, 307g propylene oxide was added at a speed of 5ml▪min ‑1 , the temperature was kept at about 95℃, vacuum aging was carried out for 3h, then the temperature was raised to 120℃, the pressure was controlled at 0.25 MPa, 10.22g of dimethylamine was added, and 718g of propylene oxide was slowly added at a speed of 5ml▪min ‑1 , the reaction was continued until the pressure in the reaction kettle became negative, the reaction was stopped, and the aging was continued for 3h. The prepared polyether was heated to 85℃, 50g of 11% mass concentration oxalic acid aqueous solution, 1.46g of magnesium silicate and 1.46g of aluminum silicate mixture were added in sequence, then stirred for 20 min, filtered, dehydrated by vacuumizing, dried at 60℃, and the polyether polyol was prepared.

[0019] In a reaction tank, N,N-dimethylacetamide 1.2 kg, polyether polyol with molecular weight of 2000 2 kg and toluene diisocyanate 0.26 kg were added, the reaction temperature was 50℃, after reaction for 3h under nitrogen atmosphere, a prepolymer solution was obtained; when the above prepolymer solution was cooled to 20℃, 0.35 kg of ethylenediamine solution was slowly added for chain extension reaction and chain termination reaction; then 1.73 g of chemical foaming agent p-toluenesulfonyl urea was added, stirred and mixed uniformly, then 3.46 g of nucleating agent aluminum methylene bis(2,4-di-t-butylphenoxy) phosphate was added, mixed and aged for 24 h, and after degassing, a spinning dope was obtained; the spinning dope was prepared into bio-based polyurethane elastic fiber by dry spinning technology, spinning, oiling and other processes. The breaking strength of the fiber was tested according to GB / T 14344-2008 "Test method for tensile properties of filaments". The fiber specification is 180 denier, the strength at 300% elongation is 28 grams, the breaking strength is 202 grams, and the breaking elongation is 526%.

[0020] Case 2.

[0021] Sucrose 342 g, glycerol 92 g, dimethylamine 4.38 g were added to the reaction kettle, and after nitrogen was replaced with air 5 times, the temperature was raised to 85℃ under vacuum, and reacted for 1.5h. 327 g of propylene oxide was added at a rate of 5 ml▪min ‑1 -1, and the temperature was kept at about 95℃. After aging for 3h under vacuum, the temperature was raised to 120℃, the pressure was controlled at 0.25 MPa, and 10.22 g of dimethylamine was added. Then 748 g of propylene oxide was slowly added at a rate of 5 ml▪min ‑1 -1, and the temperature was kept constant. The reaction was continued until the pressure in the reaction kettle became negative, the reaction was stopped, and the aging was continued for 3h. The prepared polyether was heated to 85℃, 50 g of 11% mass concentration oxalic acid aqueous solution, 1.46 g of magnesium silicate and 1.46 g of aluminum silicate mixture were added in turn, then stirred for 20 min, filtered, dehydrated by vacuum, dried at 60℃, and polyether polyol was prepared.

[0022] In a reaction tank, solvent N,N-dimethylacetamide 1.2 kg, polyether polyol with molecular weight of 2000 2 kg and toluene diisocyanate 0.26 kg were added, the stirring reaction temperature was 50℃, after reaction for 3h in nitrogen atmosphere, the prepolymer solution was obtained; when the above prepolymer solution was cooled to 20℃, 0.35 kg of ethylenediamine solution was slowly added for chain extension reaction and chain termination reaction; then 1.73 g of chemical foaming agent p-toluenesulfonyl urea was added, stirred and mixed uniformly, then 3.46 g of nucleating agent aluminum methylene bis(2,4-di-t-butylphenoxy) phosphate was added, mixed and aged for 24 h, and the spinning dope was obtained after degassing; the spinning dope was prepared into bio-based polyurethane elastic fiber by dry spinning technology, spinning, oiling and other processes. The fiber specification is 180 denier, the strength of 300% elongation is 32 grams, the breaking strength is 262 grams, and the breaking elongation is 628%.

[0023] Case 3.

[0024] Sucrose 342 g, glycerol 92 g, dimethylamine 4.38 g were added to the reaction kettle, and after nitrogen replacement for 5 times, the temperature was raised to 85℃ under vacuum, and reacted for 1.5h. 307 g of propylene oxide was added at a rate of 5 mL·min ‑1 -1, and the temperature was kept at about 95℃, and the pressure was constant. Vacuum aging for 3h, then the temperature was raised to 120℃, the pressure was controlled at 0.25 MPa, then dimethylamine 110.22 g was added, and 718 g of propylene oxide was slowly added at a rate of 5 mL·min ‑1 -1, the temperature was kept constant, and the reaction continued until the pressure in the reaction kettle became negative, the reaction was stopped, and the aging was continued for 3h. The prepared polyether was heated to 85℃, 50 g of 11% mass concentration oxalic acid aqueous solution, 1.46 g of magnesium silicate and 1.46 g of aluminum silicate mixture were added in turn, then stirred for 20 min, filtered, then dehydrated by vacuumizing, dried at 60℃, and the polyether polyol was prepared.

[0025] In a reaction tank, solvent N,N-dimethylacetamide 1.2 kg, sucrose polyether polyol with a molecular weight of 2000 2 kg and toluene diisocyanate 0.35 kg were added, the reaction temperature was 50℃, and after reaction for 3h in a nitrogen atmosphere, a prepolymer solution was obtained; when the above prepolymer solution was cooled to 20℃, 0.35 kg of ethylenediamine solution was slowly added to carry out chain extension reaction and chain termination reaction; then 1.77 g of chemical foaming agent p-toluenesulfonyl urea was added, stirred and mixed uniformly, and then 3.55 g of nucleating agent methyl bis(2,4-di-tert-butyl phenoxy) aluminum phosphate was added, mixed and aged for 24 h, and after degassing, a spinning dope was obtained; the spinning dope was spun through dry spinning technology, and after spinning, oiling and other processes, a bio-based polyurethane elastic fiber was prepared. The fiber specification is 180 denier, the strength at 300% elongation is 31 grams, the breaking strength is 282 grams, and the breaking elongation is 645%.

[0026] Comparative example:

[0027] The comparative example is Example 3 of the patent for granted publication No. CN108251912B, entitled "Preparation method of comfortable polyurethane elastic fiber", i.e. barium azodicarboxylate is added to N,N-dimethylformamide, and high-speed grinding is carried out in a ball mill to form a uniform and stable barium azodicarboxylate solution with a concentration of 30%, and the decomposition temperature of barium azodicarboxylate is 240-250℃; polyether polyol and diisocyanate are mixed to prepare -NCO terminated polyurethane prepolymer, N,N-dimethylformamide is added to fully dissolve, and a prepolymer solution is obtained; the prepolymer solution is chain-extended with diamine to obtain a polyurethane stock solution; the barium azodicarboxylate solution is added to the polyurethane stock solution, the mass of barium azodicarboxylate accounts for 0.28% of the solid content of the polyurethane stock solution, and other conventional additives are added, and after aging and degassing, a spinning dope is obtained; with the help of a dry spinning system, the spinning dope is heated and solidified into a yarn in a high-temperature duct, and after winding, a comfortable polyurethane elastic fiber is obtained. The spinning conditions are: air volume: upper in / out / upper back / down back = 0.80 / 0.60 / 0.46; temperature (℃): upper duct / middle duct / lower duct = 270 / 245 / 200; spinning speed: 950 m / min. The fiber specification is 180 denier, the strength at 300% elongation is 22 grams, the breaking strength is 182 grams, and the breaking elongation is 528%.

[0028] The dry spinning technology and process in Example 1, Example 2 and Example 3 are the same as those in the comparative example.

[0029] Of course, the protection scope of the present application is not limited to the present examples, and any similar changes made by anyone can be considered as not departing from the patent protection scope of the present application. Industrial applicability

[0030] The application ensures that the performance of the polyurethane elastic fiber is not reduced or partially improved, and meanwhile, the cost and performance advantages are considered. Table of contents free content

[0031] Enter table of contents free content description paragraph here.

Claims

1. A method for the preparation of a bio-based polyurethane elastic fiber, characterized in that, Comprising the following steps: Step A: sucrose and glycerol are added into a reaction kettle according to a molar ratio of 1-2:1, dimethylamine is added, the amount of dimethylamine added is 30-50% of the total amount of dimethylamine, under vacuum, the temperature is raised to 85-95℃, the reaction time is 1-1.5h, propylene oxide is added at a speed of 5-110ml▪min -1 , the amount of propylene oxide added is 10-30% of the total amount of propylene oxide, wherein the total amount of propylene oxide is 2-3 times the mass of sucrose; the temperature is maintained at 90-100℃, vacuum aging is carried out for 2-3h, then the temperature is raised to 120-130℃, the pressure is kept constant at 0.25-0.3MPa, the remaining dimethylamine is added, and the remaining propylene oxide is continuously added at a speed of 5-10ml▪min -1 , the reaction continues until the pressure in the reaction kettle becomes negative, the reaction is stopped, and aging is continued for 2-3h, the temperature is controlled at 80-90℃, 50-60g of oxalic acid aqueous solution with a mass concentration of 11%-12% is added, and a mixture of magnesium silicate and aluminum silicate is added, the mass concentration of the mixture of magnesium silicate and aluminum silicate is 0.1-0.2% of the total amount of sucrose, glycerol and propylene oxide, the mass concentration of dimethylamine is 1-3% of the total amount of sucrose, glycerol and propylene oxide, then stirring is carried out for 20-30min, followed by filtration, dehydration by vacuum extraction, drying at 60-70℃, and the polyether polyol is prepared. Step B: adding solvent N, N-dimethylacetamide, polyether polyol of step A and polyisocyanate in a reaction tank, the mass concentration of the solvent is 45-65%, the molar ratio of polyether polyol and polyisocyanate compound is 1:1.5-1:2, the reaction temperature is 45-60℃, after reacting for 2-3h in a nitrogen atmosphere, a prepolymer solution is obtained; when the prepolymer solution is cooled to 10-20℃, a mixed amine solution is added for chain extension reaction and chain termination reaction to form a polyurethane solution, the mass fraction of the mixed amine solution in the polyurethane solution is 5-10%; p-toluenesulfonyl urea with a mass concentration of 0.05-0.08% in the polyurethane solution is added, stirred and mixed uniformly, then aluminum methylene bis(2,4-di-tert-butylphenoxy) phosphate with a dosage of 0.1-0.5% in the polyurethane solution is added, mixed and aged for 20-24h, and after degassing, a spinning dope is obtained; the spinning dope is spun through dry spinning technology, oiled, and bio-based polyurethane elastic fiber is prepared.

2. The method of producing a bio-based polyurethane elastic fiber according to claim 1, wherein The mass ratio of magnesium silicate to aluminum silicate in the magnesium silicate and aluminum silicate mixture is 1:

1.

3. The method of producing a bio-based polyurethane elastic fiber according to claim 2, wherein The polyisocyanate is one or a mixture of two of toluene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate.

4. The method of producing a bio-based polyurethane elastic fiber according to claim 3, wherein The amine solution is prepared by mixing and dissolving ethylenediamine, propylenediamine and diethylamine in dimethylacetamide at a molar ratio of 1:1:

1.

5. The method of producing a bio-based polyurethane elastic fiber according to claim 4, wherein The molecular weight of the polyether polyol is 1500-3000.