Thermoplastic polyurethane elastic fiber and preparation method thereof
阅读说明：本技术 热塑性聚氨酯弹性纤维及其制备方法 (Thermoplastic polyurethane elastic fiber and preparation method thereof ) 是由 袁仁能 陈斌 范东风 陈敏 施龙敏 陈光静 李俊江 马肥 陈天培 夏冬 于 2019-03-22 设计创作，主要内容包括：本发明公开了一种热塑性聚氨酯弹性纤维及其制备方法,包含以下质量分数的组份：异氰酸酯15～40％,聚合物多元醇53～83％,扩链剂2～8％,扩链剂选自小分子二醇与二胺混合物。本发明通过在TPU分子结构中引入一定量的含氮杂环结构的二胺与小分子二醇形成混合扩链剂,与其他含常规芳香族二胺的TPU弹性纤维材料相比,本发明可较低温度下可进行贴合,同时可有效改善材料的可纺性的同时提高回弹性。(The invention discloses a thermoplastic polyurethane elastic fiber and a preparation method thereof, wherein the thermoplastic polyurethane elastic fiber comprises the following components in percentage by mass: 15-40% of isocyanate, 53-83% of polymer polyol and 2-8% of chain extender, wherein the chain extender is selected from a mixture of micromolecular diol and diamine. According to the invention, a certain amount of diamine containing a nitrogen heterocyclic structure and micromolecular diol are introduced into the molecular structure of the TPU to form the mixed chain extender, so that the TPU elastic fiber material can be attached at a lower temperature compared with other TPU elastic fiber materials containing conventional aromatic diamine, and meanwhile, the spinnability of the material can be effectively improved and the rebound resilience can be improved.)
1. The thermoplastic polyurethane elastic fiber is characterized by comprising the following components in percentage by mass:
(a) 15-40% of isocyanate
(b) 53-83% of polymer polyol
(c) 2-8% of chain extender
The chain extender is selected from a mixture of small molecule diol and diamine.
2. The thermoplastic polyurethane elastic fiber according to claim 1, wherein the small molecule diol is one or a combination of 1, 2-Ethylene Glycol (EG), 1, 3-propylene glycol (PDO), 1, 4-Butanediol (BDO) and 1, 6-Hexanediol (HDO), and the small molecule diamine is a nitrogen heterocyclic diamine.
3. The thermoplastic polyurethane elastic fiber according to claim 2, wherein the small molecule diamine is selected from the group consisting of 2, 4-diaminopyridine, 2, 4-diaminopyrimidine, ethyl ester 2, 4-diamino-pyrimidine-5-carboxylic acid, 2, 4-diamino-6-ethoxypyrimidine, 2, 4-diamino-1, 3, 5-triazine, 6-nonyl-2, 4-diamino-1, 3, 5-triazine, 6-methyl-2, 4-diamino-1, 3, 5-triazine, 6-pentyl-2, 4-diamino-1, 3, 5-triazine, 2-chloro-4, 6-diamino-1, 3, 5-triazine, and mixtures thereof, 2, 4-diamino-6- (4-methylphenyl) -1,3, 5-triazine, or a combination thereof.
4. The thermoplastic polyurethane elastic fiber according to claim 1, wherein the mass ratio of the small molecule diol to the diamine mixture is: small molecule diol: the ratio of the small-molecular diamine to the small-molecular diamine is 1: 0.05-1.
5. The thermoplastic polyurethane elastic fiber according to claim 1, wherein the chain extender is a mixture of 2, 4-diamino-6-ethoxypyrimidine and PDO, PDO: 2, 4-diamino-6-ethoxypyrimidine ═ 1: 0.85; or the following steps:
mixture of 2, 4-diamino-6-nonyl-1, 3, 5-triazine with BDO, BDO: 2, 4-diamino-6-nonyl-1, 3, 5-triazine 1: 0.176; or the following steps:
a mixture of 2, 4-diamino-6-ethoxypyrimidine and PDO, PDO: 2, 4-diamino-6-ethoxypyrimidine ═ 1: 0.15; or the following steps:
mixture of 2, 4-diamino-6-ethoxypyrimidine and HDO, HDO: 2, 4-diamino-6-ethoxypyrimidine (1: 0.0517); or the following steps:
mixture of 2, 4-diaminopyridine with PDO, PDO: 2, 4-diaminopyridine ═ 1:0.130, or is:
mixture of 2, 4-diaminopyridine PDO, PDO: 2, 4-diaminopyridine ═ 1: 1.
6. The thermoplastic polyurethane elastic fiber according to claim 1, wherein the isocyanate is selected from one or a combination of diphenylmethane diisocyanate (MDI), Toluene Diisocyanate (TDI), 1, 6-Hexamethylene Diisocyanate (HDI), 4-dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), p-phenylene diisocyanate (PPDI);
the polymer polyol is selected from one or the combination of polyester polyol or polyether polyol;
the polyester polyol is prepared by polycondensation of 1, 6-adipic acid and 1, 2-ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol or 1, 6-hexanediol micromolecule diol, and the number average molecular weight is 2000-5000;
the polyether polyol is selected from one or a combination of polytetramethylene ether glycol (PTMEG), polyethylene glycol (PEG), polypropylene glycol (PPG), poly-1, 2-propylene glycol (PPG), poly-1, 3-propylene glycol (PO3G) and polyethylene glycol-propylene glycol copolymer (PEG-co-PPG, CAS:9038-95-3), and preferably polytetramethylene ether glycol (PTMEG) and polyethylene glycol (PEG), and the number average molecular weight of the polyethylene glycol-propylene glycol copolymer (PEG-co-PPG) is 500-3000.
7. The thermoplastic polyurethane elastic fiber according to claim 1, further comprising a catalyst and an auxiliary.
8. The thermoplastic polyurethane elastic fiber according to claim 1, wherein the thermoplastic polyurethane elastic fiber has a weight per unit length of 20 to 100D.
9. The method for preparing thermoplastic polyurethane elastic fiber according to claim 1, wherein the thermoplastic polyurethane fiber is obtained by melt spinning thermoplastic polyurethane particles obtained by continuous polymerization or prepolymerization.
10. The method for preparing the thermoplastic polyurethane elastic fiber according to claim 9, comprising the steps of:
dispersing and mixing the isocyanate, the polyester polyol, the chain extender and the catalyst auxiliary agent through a mixing head, then pouring the mixture into a double-screw reaction extruder, carrying out reaction extrusion, carrying out underwater granulation, dewatering, drying and curing to obtain thermoplastic polyurethane particles; and (3) dehumidifying, drying and carrying out melt spinning to obtain the thermoplastic polyurethane elastic fiber, wherein the extrusion temperature is 180-200 ℃.
Technical Field
The invention relates to thermoplastic polyurethane and a preparation method thereof, in particular to a thermoplastic polyurethane elastomer capable of melt spinning at low temperature.
Background
The Thermoplastic Polyurethane (TPU) elastic fiber is prepared by methods such as dry spinning (dry spinning), wet spinning (wet spinning), melt spinning (melt spinning) and the like, wherein the dry spinning is the most common method, however, a volatile solvent is required to be added in the production process of the TPU fiber, so that the environment is polluted to a certain extent, meanwhile, the operation process of recovering the solvent also increases the production cost, and if the solvent is not volatilized, the health of a human body is influenced in the using and wearing process. In recent years, because melt spinning does not adopt solvents, does not pollute the environment and has less product equipment investment, research on preparing TPU elastic fibers by melt spinning is more and more, but the spinnability, low-temperature processability and fiber rebound rate of the melt spun TPU fibers are not satisfactory at present.
Patent CN99108972.3 proposes a method for manufacturing TPU fiber, which uses polyether polyol and polyester polyol as intermediates, and introduces micromolecular aliphatic diol and aliphatic diamine into the TPU structure, so as to increase the urea bond content of TPU, improve the spinnability of the material, but reduce the rebound resilience and flexibility to a certain extent, and in addition, the addition of aliphatic diamine increases the difficulty of the process, resulting in inconsistent product quality. Patent CN200610084136.0 reports that a TPU capable of being processed into film or fiber simultaneously uses conventional diisocyanate, two kinds of hydrophobic and hydrophilic polyols (polytetramethylene ether glycol, propylene oxide polyol), and a mixed chain extender of low molecular weight glycol and aromatic diamine (trimethylene glycol di-p-aminobenzoate) as main raw materials, and although aromatic diamine improves resilience of fiber, the processing temperature is higher, the processing range is narrow, the difficulty of melt spinning processing is increased, and the uniformity of the obtained fiber is poor. In patent CN200710170876.0, which is similar to patent CN200610084136.0, a soft segment containing silicone with silicone bond and a hard segment containing aromatic diamine capable of forming urea bond are introduced into TPU in a proper proportion, so as to improve the properties of fiber hardness, tensile strength, resilience and the like, wherein the introduction of aromatic diamine also makes spinning processing difficult, and the addition of the soft segment containing silicone with silicone bond does not bring about a significant improvement to the material properties.
Disclosure of Invention
The invention aims to provide a thermoplastic polyurethane elastic fiber and a preparation method thereof, which are used for overcoming the defects in the prior art.
The thermoplastic polyurethane elastic fiber comprises the following components in percentage by mass:
(a) 15-40% of isocyanate
(b) 53-83% of polymer polyol
(c) 2-8% of chain extender
Wherein:
the isocyanate is selected from one or the combination of diphenylmethane diisocyanate (MDI), Toluene Diisocyanate (TDI), 1, 6-Hexamethylene Diisocyanate (HDI), 4-dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI) and p-phenylene diisocyanate (PPDI);
the polymer polyol is selected from one or the combination of polyester polyol or polyether polyol;
the polyester polyol is prepared by polycondensation of 1, 6-adipic acid and 1, 2-ethylene glycol, 1, 3-propylene glycol, 1, 4-butanediol or 1, 6-hexanediol micromolecule diol, and the number average molecular weight is 2000-5000;
the polyether polyol is selected from one or a combination of polytetramethylene ether glycol (PTMEG), polyethylene glycol (PEG), polypropylene glycol (PPG), poly-1, 2-propylene glycol (PPG), poly-1, 3-propylene glycol (PO3G) and polyethylene glycol-propylene glycol copolymer (PEG-co-PPG, CAS:9038-95-3), preferably polytetramethylene ether glycol (PTMEG) and polyethylene glycol (PEG), and the number average molecular weight of the polyethylene glycol-propylene glycol copolymer (PEG-co-PPG) is 500-3000;
the chain extender is a mixture of micromolecular diol and diamine;
the small molecular diol is one or a combination of 1, 2-Ethanediol (EG), 1, 3-Propanediol (PDO), 1, 4-Butanediol (BDO) and 1, 6-Hexanediol (HDO);
the small molecule diamine is a nitrogen heterocyclic type diamine, for example, 2, 4-diaminopyridine, 2, 4-diaminopyrimidine,
preferably, the small-molecule diamine is 2, 4-diaminopyridine, 2, 4-diamino-6-ethoxypyrimidine, 2, 4-diamino-6-nonyl-1, 3, 5-triazine;
the mass ratio is as follows:
small molecule diol: the ratio of the small-molecular diamine to the small-molecular diamine is 1: 0.05-1;
further, the chain extender is a mixture of 2, 4-diamino-6-ethoxy pyrimidine and PDO, wherein the weight ratio of PDO: 2, 4-diamino-6-ethoxypyrimidine ═ 1: 0.85; or the following steps:
mixture of 2, 4-diamino-6-nonyl-1, 3, 5-triazine with BDO, BDO: 2, 4-diamino-6-nonyl-1, 3, 5-triazine 1: 0.176; or the following steps:
a mixture of 2, 4-diamino-6-ethoxypyrimidine and PDO, PDO: 2, 4-diamino-6-ethoxypyrimidine ═ 1: 0.15; or the following steps:
mixture of 2, 4-diamino-6-ethoxypyrimidine and HDO, HDO: 2, 4-diamino-6-ethoxypyrimidine (1: 0.0517); or the following steps:
mixture of 2, 4-diaminopyridine with PDO, PDO: 2, 4-diaminopyridine ═ 1:0.130, or is:
mixture of 2, 4-diaminopyridine PDO, PDO: 2, 4-diaminopyridine ═ 1: 1;
further, the catalyst also includes catalysts commonly used in the field, including organic tin catalysts, potassium carboxylate catalysts, organic heavy metal catalysts, zinc carboxylates, bismuth carboxylates, titanate catalysts, and the like, and specifically, the amount of the catalyst used is 0.001 to 0.1% of the total mass of the reactants, as reported in the handbook of polyurethane elastomers (edited by liu-thick jun, chemical industry press, second edition).
Preferably, auxiliaries commonly used in the art, including antioxidants, plasticizers, ultraviolet absorbers, light stabilizers, and the like, can be further added, and specifically, refer to handbook of polyurethane raw materials and auxiliaries (Liu Yijun, chemical industry Press, second edition).
The unit length weight of the thermoplastic polyurethane elastic fiber is 20-100D;
optionally, the preparation method of the thermoplastic polyurethane fiber can adopt continuous polymerization reaction or prepolymerization reaction to obtain thermoplastic polyurethane particles, and the thermoplastic polyurethane fiber is obtained through melt spinning.
Further, the method can comprise the following steps:
dispersing and mixing the isocyanate, the polymer polyol, the chain extender and the catalyst auxiliary agent through a mixing head, then pouring the mixture into a double-screw reaction extruder, carrying out reaction extrusion, carrying out underwater granulation, dewatering, drying and curing to obtain thermoplastic polyurethane particles; and after dehumidification and drying, the thermoplastic polyurethane elastic fiber can be obtained through melt spinning.
The extrusion temperature is 180-200 ℃;
the invention has the beneficial effects that:
according to the invention, a certain amount of diamine containing a nitrogen heterocyclic structure and micromolecular diol are introduced into the molecular structure of the TPU to form the mixed chain extender, so that the TPU elastic fiber material can be attached at a lower temperature compared with other TPU elastic fiber materials containing conventional aromatic diamine, and meanwhile, the spinnability of the material can be effectively improved and the rebound resilience can be improved.
Drawings
FIG. 1 is a drawing of a 20D TPU elastic fiber made in example 6 after the fiber has been wound into a roll;
FIG. 2 is a graph of the elongation at break test of the 20D TPU elastic fiber prepared in example 6;
FIG. 3 is a graph of the filament to filament bond strength test of a 20D TPU elastic fiber prepared in example 6;
FIG. 4 is a rebound testing chart of the 20D TPU elastic fiber prepared in example 6;
Detailed Description
The present invention is further described below with reference to examples.