CN110283297B

CN110283297B - Hyperbranched polyurethane, modified PET/PTT elastic fiber, preparation methods of hyperbranched polyurethane and modified PET/PTT elastic fiber, and fabric

Info

Publication number: CN110283297B
Application number: CN201910578099.6A
Authority: CN
Inventors: 赖宇坤; 陈金星; 劳作恬; 叶介茂
Original assignee: Xiamen Anta Sports Goods Co Ltd
Current assignee: Xiamen Anta Sports Goods Co Ltd
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2021-06-29
Anticipated expiration: 2039-06-28
Also published as: CN110283297A

Abstract

The invention provides hyperbranched polyurethane with the viscosity of 1880-1890 mPa & s, which is prepared by the following steps: mixing polytetrahydrofuran 1000, isophorone diisocyanate and 1, 4-butanediol, and reacting at 80-100 ℃ by taking dibutyltin dilaurate as a catalyst to obtain a polyurethane intermediate; mixing the polyurethane intermediate, a first-generation hydroxyl-terminated hyperbranched polymer and a hydrophilic chain extender, and then reacting to obtain hyperbranched polyurethane; the hydrophilic chain extender is dimethylolpropionic acid, dimethylolbutyric acid and N, N-dihydroxyethyl-2-aminopropionic acid. The invention provides a modified PET/PTT elastic fiber, a preparation method thereof and a fabric, wherein the preparation raw material of the fiber comprises the hyperbranched polyurethane. The fiber has better elasticity and high moisture regain. The PET slice raw material can be from a waste recovered plastic bottle, and the PTT slice raw material is from bio-based fermentation, so that the consumption of petroleum resources can be reduced.

Description

Hyperbranched polyurethane, modified PET/PTT elastic fiber, preparation methods of hyperbranched polyurethane and modified PET/PTT elastic fiber, and fabric

Technical Field

The invention relates to the technical field of PET/PTT fibers, in particular to hyperbranched polyurethane, modified PET/PTT elastic fibers, and preparation methods and fabrics thereof.

Background

PET/PTT fibers, i.e., bicomponent fibers of PET (polyethylene terephthalate) and PTT (polytrimethylene terephthalate). The cross-sectional morphology of some commercially available PET/PTT bicomponent filaments is shown in FIG. 1 (10 KV applied, 3000 times magnification, 3 μm scale), which is a profiled cross-section fiber. The bicomponent filament is mainly prepared by a melt spinning process; the raw fiber materials used for production are common PET and PTT slices which are all derived from petroleum resources. Because the PTT fiber has the characteristics of terylene, chinlon and acrylon, the PET/PTT fiber has the characteristics of easy dyeing, soft hand feeling, high elasticity and the like besides good antifouling performance. Wherein, the extensibility of the PET/PTT fiber is as good as that of spandex fiber, but the PET/PTT fiber is easier to process compared with spandex fiber which is elastic fiber, and is very suitable for textile production of clothing fabric. Besides, the bicomponent fiber also has the characteristics of dryness, stiffness, smoothness and the like. Therefore, in the near future, the bicomponent fiber will gradually replace spandex and become a novel elastic fiber in the 21 st century.

However, the elasticity of the currently produced PET/PTT bicomponent fiber is to be improved, and the moisture regain is low, so that the wearing comfort of the PET/PTT bicomponent fiber used as a garment fabric is poor.

Disclosure of Invention

In view of the above, the present application aims to provide a hyperbranched polyurethane, a modified PET/PTT elastic fiber, and a preparation method and a fabric thereof.

The invention provides hyperbranched polyurethane which is prepared by the following steps:

mixing polytetrahydrofuran 1000, isophorone diisocyanate and 1, 4-butanediol, and reacting at the temperature of 80-100 ℃ by taking dibutyltin dilaurate as a catalyst to obtain a polyurethane intermediate;

mixing the polyurethane intermediate, the first-generation hydroxyl-terminated hyperbranched polymer and a hydrophilic chain extender, and then reacting to obtain hyperbranched polyurethane; the hydrophilic chain extender is dimethylolpropionic acid, dimethylolbutyric acid and N, N-dihydroxyethyl-2-aminopropionic acid;

the viscosity of the hyperbranched polyurethane at 30 ℃ is 1880-1890 mPa · s.

Preferably, the hydroxyl value of the hyperbranched polyurethane is 390 to 399 mgKOH/g.

The invention provides a modified PET/PTT elastic fiber, which is prepared from the following raw materials: hyperbranched polyurethanes as hereinbefore described.

The invention provides a preparation method of a modified PET/PTT elastic fiber, which comprises the following steps:

providing a PET slice and a PTT slice; the raw materials for preparing the PET slices and/or the PTT slices comprise hydrophilic substances, and the hydrophilic substances are the hyperbranched polyurethane;

melting the PET slices to obtain a PET melt, and melting the PTT slices to obtain a PTT melt;

and mixing the PET melt and the PTT melt, and spinning to obtain the modified PET/PTT elastic fiber.

Preferably, the PET raw material of the PET slices is from waste recycled PET plastic bottles; the PTT component of the PTT slice is formed by esterification and polymerization reaction of 1, 3-propanediol and terephthalic acid, and the 1, 3-propanediol is prepared by a biological fermentation method.

Preferably, the PET chip is prepared according to the following steps:

sequentially cleaning, crushing and drying the waste recycled PET plastic bottles to obtain PET fragments;

mixing the PET fragments and hydrophilic substances, and stirring at 100-270 ℃ for reaction to obtain PET reaction liquid; the hydrophilic substance is the hyperbranched polyurethane;

and (3) granulating the PET reaction solution under water at the temperature of 120-190 ℃, and drying to obtain the PET slices with the viscosity of 0.6-0.9mPa & s.

Preferably, the PTT slices are prepared by the following steps:

terephthalic acid and 1, 3-propanediol prepared by a biological fermentation method are mixed according to the ratio of 2: 1.2-2: 1.5, taking an acrylate as a thickening agent, and stirring for reaction at the temperature of 150-270 ℃ to obtain a PTT reaction solution;

and (3) carrying out water granulation on the PTT reaction liquid at the temperature of 160-200 ℃, and drying to obtain PTT slices with the viscosity of 1.2-1.5mPa & s.

Preferably, the melting temperature of the PET slices is 200-250 ℃, and the melting temperature of the PTT slices is 230-270 ℃; the mass ratio of the PET melt to the PTT melt is 40-60: 40-60.

Preferably, the modified PET/PTT elastic fiber further comprises an auxiliary ingredient, and the auxiliary ingredient is selected from one or more of an antistatic agent, an antioxidant and a lubricant.

The invention provides a fabric which comprises the modified PET/PTT elastic fiber obtained by the preparation method.

Compared with the prior art, the invention firstly synthesizes the hyperbranched polyurethane with a new structure, and the end group of the hyperbranched polyurethane has a plurality of hydroxyl groups; the viscosity of the hyperbranched polyurethane at 30 ℃ is 1880-1890 mPa · s. In the process of preparing the PET/PTT elastic fiber, the hyperbranched polyurethane is added, so that the elasticity of the bi-component yarn is superior to that of the conventional PET/PTT fiber, the moisture regain of the bi-component yarn can be improved, and the bi-component yarn has better hydrophilic hygroscopicity.

Furthermore, in the specific embodiment of the invention, the PET slice raw material can be from a waste recovered PET plastic bottle, and the PTT slice raw material can be from bio-based fermentation, so that the consumption of petroleum resources can be reduced, and the environment protection is facilitated.

Drawings

FIG. 1 is a cross-sectional SEM photograph of a conventional PET/PTT bicomponent filament;

FIG. 2 is an infrared spectrum of a hyperbranched polyurethane prepared in example 1 of the present invention;

FIG. 3 is a comparison of water contact angles of fabrics prepared in example 3 of the present invention versus a conventional bi-component fabric;

FIG. 4 shows the water contact angle test results of the fabric prepared in example 4 of the present invention;

fig. 5 shows the water contact angle test result of the fabric prepared in example 5 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides hyperbranched polyurethane which is prepared according to the following steps:

The hyperbranched polyurethane provided by the invention is a water-based polymer material and can be used for preparing bi-component fibers with excellent moisture absorption, elasticity and the like.

The hyperbranched polyurethane provided by the invention contains urethane groups and hydroxyl groups on the molecular structure, does not contain NCO groups, and has a cyclic structure as the whole molecule. The viscosity of the hyperbranched polyurethane at 30 ℃ is 1880-1890 mPa & s; the hydroxyl value may be 390 to 399 mgKOH/g. In some embodiments of the invention, the hyperbranched polyurethane has a number average molecular weight of 1348, a weight average molecular weight of 1702, a polydispersity of 1.26; hydroxyl value of 399mgKOH g^-1And a viscosity of 1883 mPas at 30 ℃.

In the preparation process of the hyperbranched polyurethane, polytetrahydrofuran 1000, isophorone diisocyanate and 1, 4-butanediol are firstly filled into a reaction kettle, a stirrer and a condenser pipe are arranged in the reaction kettle, then a catalyst dibutyltin dilaurate is added, and the reaction is carried out for 1 to 2 hours at the temperature of 80 to 100 ℃ to obtain a polyurethane intermediate.

Wherein, the polytetrahydrofuran 1000 is abbreviated as PTMG1000, which is a polyol structure and has a structural formula shown in formula 1, and n is 1000. Isophorone diisocyanate (IPDI) has a cyclic structure and an NCO group, and the structure is shown in the following formula 2. The structure of 1, 4-Butanediol (BDO) is shown in formula 3; dibutyl tin dilaurate, DBTDL for short, is a catalyst. The reaction temperature is preferably 80-85 ℃; the structure of the polyurethane intermediate obtained by the reaction is shown in the following formula 4. Further, the total volume of the reaction liquid was 300L; the concentrations of the polytetrahydrofuran, the isophorone diisocyanate, the 1, 4-butanediol and the catalyst can be respectively as follows: 100-150g/L, 10-20g/L, 20-40g/L and 5-15 g/L.

After obtaining the polyurethane intermediate, the first-generation hydroxyl-terminated hyperbranched polymer is added, the hydrophilic chain extender is added, and the reaction can be continued for 2.5 hours at 85 ℃ to obtain the hyperbranched polyurethane.

The first-generation hydroxyl-terminated hyperbranched polymer can be synthesized by one-step feeding by adopting a nucleated one-step method according to a literature method (the research progress of the hyperbranched polymer, the Chinese traditional medicine and the medical science), and controlling the molar ratio of the monomer to the central core according to the algebra of the hyperbranched polymer. The structure of the first-generation hydroxyl-terminated hyperbranched polymer is shown in a formula 5, and is called HPAE for short. The invention uses dimethylolpropionic acid (DMPA), dimethylolbutyric acid (DMBA) and N, N-dihydroxyethyl-2-aminopropionic acid (DMCA) as hydrophilic chain extenders to obtain aqueous hyperbranched polyurethane, and the structure of the aqueous hyperbranched polyurethane is shown in formula 6. In the reaction system, the concentration of the first-generation hydroxyl-terminated hyperbranched polymer is 30-60 g/L; and respectively adding 10-30g/L dimethylolpropionic acid, 20-40g/L dimethylolbutyric acid and 30-50g/L carboxylic acid type monomer DMCA as hydrophilic chain extenders, and reacting to obtain the hyperbranched polyurethane with the structure and the performance.

The invention provides a modified PET/PTT elastic fiber, and the preparation raw material comprises the hyperbranched polyurethane. The hyperbranched polyurethane has hygroscopic groups-OH at the tail end, and is polymerized on the branched chain of PET and/or PTT, so that the elasticity of the bi-component fiber yarn can be further improved, the moisture regain of the bi-component yarn is improved, and the hydrophilic hygroscopicity of the bi-component yarn is better.

Specifically, the embodiment of the invention provides a preparation method of a modified PET/PTT elastic fiber, which comprises the following steps:

The method comprises the following steps of firstly preparing a PET slice and a PTT slice; the PET raw material of the PET slices comes from waste recycled PET plastic bottles, for example, the recycled mineral water bottles are melted and granulated again to prepare the PET slices, so that the waste utilization is realized, the consumption of resources in the nature is reduced, and the pollution of waste plastics to the environment is reduced.

Wherein, the PTT component of the PTT slice is formed by esterification and polymerization reaction of 1, 3-propanediol and terephthalic acid; the 1, 3-propylene glycol is preferably prepared by adopting a biological fermentation method, particularly, wastes such as corn, straw and the like in nature are recycled and prepared by a microbial fermentation method, so that the bio-based environmental protection of the PTT slices is improved, and the environment-friendly PET/PTT bi-component fiber is finally obtained.

In some embodiments of the invention, in the preparation process of the PET chip, the hyperbranched polyurethane is used as a hydrophilic modification substance, and the hyperbranched polyurethane can be polymerized on the branched chain of the PET, so that the physicochemical properties of the PET chip are obviously changed, the melt viscosity of the PET is effectively reduced, and the subsequent preparation of the bi-component fiber with excellent elasticity is facilitated. Specifically, the PET chip is preferably produced according to the following steps:

mixing the PET fragments with the hydrophilic substance hyperbranched polyurethane, and then stirring and reacting at 100-270 ℃ to obtain a PET reaction solution;

The embodiment of the invention firstly carries out pretreatment on the waste and recycled PET plastic bottle: the PET bottle chips are subjected to primary screening and primary cleaning, then the PET bottle chips are crushed into PET bottle chips with the maximum length of 18-20 mm, and then the PET bottle chips are dried after passing through a cleaning assembly line to obtain PET chips.

Then, the embodiment of the invention carries out pulping: pressing the obtained PET fragments into an esterification kettle, preferably adding 30-60g/L of the hyperbranched polyurethane (based on the total volume of 300L of reaction liquid in the reaction kettle) under the protection of normal pressure nitrogen, stirring and reacting at 100-270 ℃ for 1-4 hours, and condensing and discharging generated water to obtain the clear and transparent polyester liquid which has the viscosity of 0.2-0.4mPa & s, low viscosity and hydrophilic moisture regain of 2-3% and high hydrophilic moisture absorption, and is PET reaction liquid.

After the PET reaction liquid is obtained, the slice prepared by the embodiment of the invention is as follows: and (3) putting the liquid into a reaction double-screw rod, granulating at the granulation reaction temperature of 120-190 ℃, granulating underwater, drying, and packaging to obtain the PET slices with the molecular weight of 400-500 KDa, the average particle size of 6-9 microns and the viscosity of 0.6-0.9mPa & s.

In addition, in the embodiment, the PTT slices are individually tackified; the PTT slice is prepared by the following steps:

according to the following steps: 1.2-2: 1.5, mixing terephthalic acid and 1, 3-propanediol prepared by a biological fermentation method, taking an acrylate substance as a thickening agent, and stirring for reaction at the temperature of 150-270 ℃ to obtain a PTT reaction solution;

The 1, 3-propanediol prepared by the biological fermentation method can be a commercial product or can be prepared by itself, and the process is as follows:

(1) pulping: the starch raw materials such as corn, straw and the like are fully crushed, and the obtained crushed starch raw materials are mixed with stirring water to form starch solution.

(2) Saccharification and fermentation: saccharifying enzyme (Aspergillus oryzae) is added into the amylolysis solution to prepare a saccharifying solution. This step hydrolyzes the alpha-1, 4 and alpha-1, 6 glycosidic linkages of polysaccharides (starch, glycogen, etc.) to glucose.

(3) Aerobic fermentation: 2-10g/L saccharifying enzyme (Aspergillus oryzae) is added into the saccharifying solution, a fermentation container needs to have a constant temperature control function, the temperature is constant, the fermentation temperature is kept at 42-45 ℃, the fermentation time is 48-72 hours, and the stirring is carried out for 5 minutes every 4 hours, so that the alpha-1, 4 and alpha-1, 6 glycosidic bonds of polysaccharides (starch, glycogen and the like) can be hydrolyzed to form glycerol fermentation liquor.

(3) Anaerobic fermentation: filtering the glycerol fermentation liquid, filtering the filtrate, transferring the filtrate into another fermentation tank, adding Klebsiella pneumoniae (5-10g/L), maintaining the fermentation temperature at 42-45 deg.C for 72-108 hr, and performing anaerobic fermentation to obtain 1, 3-propylene glycol liquid.

In the embodiment of the invention, the 1, 3-propanediol prepared by the biological fermentation method and terephthalic acid are subjected to esterification and polymerization reaction. Wherein the mass ratio of the terephthalic acid to the 1, 3-propanediol is 2: 1.2-2: 1.5. and adding an acrylate thickener in the reaction process, stirring and reacting for 2-4 hours at 150-270 ℃, and condensing and discharging generated water to obtain a PTT clear transparent liquid with the viscosity of 0.7-1.3mPa & s and high viscosity, which is a PTT reaction liquid.

After the PTT reaction solution is obtained, the slice prepared by the embodiment of the invention is as follows: and (3) putting the liquid into a reaction double-screw rod, granulating at the granulation reaction temperature of 160-200 ℃, granulating underwater, drying, and packaging to obtain PTT slices with the molecular weight of 600-700 KDa, the average particle size of 6-9 microns and the viscosity of 1.2-1.5mPa & s.

After obtaining the PET slices and the PTT slices, the PET slices and the PTT slices are respectively melted into corresponding PET melts and PTT melts. Specifically, the PTT slices enter a screw extruder for extrusion, and are heated and melted at 230-270 ℃, and the temperature for melting the PET slices is 200-250 ℃.

According to the embodiment of the invention, the PET melt is mixed with the PTT melt fed through the PTT melt distribution pipe in the PET melt distribution pipe, then spinning production is carried out according to a conventional process to obtain a semi-finished product of the pre-oriented yarn barrel yarn, and then elastic development treatment is carried out through a drafting winding machine to obtain a finished product of the modified PET/PTT elastic yarn.

Wherein the mass ratio of the PET melt to the PTT melt is generally 40-60: 40-60, preferably 60: 40. in addition, the modified PET/PTT elastic fiber preferably further comprises an auxiliary ingredient, and the auxiliary ingredient can be selected from one or more of antistatic agents, antioxidants and lubricants. The auxiliary agent is added in the process of spinning by a double-screw machine; for example, 1.5% of antistatic JML (Rodaff corporation) and 2.5% of antioxidant P-3(Archoma corporation) are used.

In the embodiment of the invention, the melt spinning process specifically comprises the following steps:

1. adding the dried fiber-forming high polymer chips from a polymer hopper, sequentially melting, mixing, metering and extruding by a screw extruder which is heated in sections according to requirements, and feeding the fiber-forming high polymer chips into a melt metering pump through a bent pipe between the extruder and a spinning box body.

2. The melt is quantitatively extruded from the small holes of the spinning nozzle by a metering pump arranged in the spinning box body to form melt trickles.

3. The melt trickle enters a channel and is cooled and solidified at a lower temperature (40 ℃) in a cooling and blowing environment to form nascent fiber.

4. And oiling and networking the nascent fiber, and winding the nascent fiber into a bobbin.

5. The coiled yarn is subjected to secondary forming processing such as subsequent drawing-heat setting and the like to prepare finished fiber with practicability. In the drawing and winding process, the drawing multiple is as follows: the stretching ratio of the high-speed silk stretching process is 1.5-1.7; the drawing speed is 1000-1200 MPM; the winding speed is 8000-10000 RPM; the twist is 10-15.

The embodiment of the invention can produce the environment-friendly PET/PTT elastic fiber with high elastic recovery and high hydrophilicity and moisture absorption, and can weave fabrics such as clothing fabrics with better comfort and the like. In addition, the hyperbranched polyurethane can also be added into the PTT slices at the same time, so that the hydrophilicity is further improved. The operation of preparing the PTT slices by using the hyperbranched polyurethane as the hydrophilic substance is the same as the preparation process, and is not described again here.

The invention provides a fabric which comprises the modified PET/PTT elastic fiber obtained by the preparation method. The fabric can be woven fabric or knitted fabric, can be pure-spun or blended interwoven fabric, and is not particularly limited in the invention. The fabric has good elasticity, hydrophilic hygroscopicity and wearing comfort.

In order to further understand the present application, the hyperbranched polyurethane, the modified PET/PTT elastic fiber, and the preparation method and fabric thereof provided by the present invention are specifically described below with reference to examples.

Example 1 preparation of hydrophilic hyperbranched polyurethanes:

100g/L polytetrahydrofuran 1000, 10g/L isophorone diisocyanate and 20 g/L1, 4-butanediol are filled into a reaction kettle provided with a stirrer and a condenser tube, 5g/L dibutyltin dilaurate is added as a catalyst, the reaction is carried out for 1h under an oil bath at 80 ℃, 30g/L of first-generation hydroxyl Hyperbranched Polymer (HPAE) is added, 10g/L dimethylolpropionic acid, 20g/L dimethylolbutyric acid and 30g/L of carboxylic acid type monomer (DMCA) are added as hydrophilic chain extenders, and the reaction is continued for 2.5h at 85 ℃, so that the hydrophilic hyperbranched polyurethane is obtained.

The number average molecular weight of the hyperbranched polyurethane is 1348, the weight average molecular weight is 1702, the polydispersity is 1.26, and the hydroxyl value is 399mgKOH g^-1The viscosity of the hyperbranched compound at 30 ℃ is 1883mPa & s.

And (3) carrying out infrared analysis on the hyperbranched polyurethane, wherein a specific infrared spectrogram is shown in figure 2. The infrared spectrogram analysis result is as follows: 3444cm^-1The strong absorption peak of (2) is attributed to O-H stretching vibration of hydroxyl group, 3361cm^-1The absorption peak of (2) is caused by stretching vibration of the N-H bond, and the peak width is caused by overlapping of the O-H and N-H absorption peaks. 2950cm^-1The absorption peak of (A) is represented by CH and CH₂、CH₃And C-H stretching vibration of (a). 1697cm^-1The strong peak of (2) is a stretching vibration absorption peak of the carbonyl group. 1548cm^-1The absorption peak of (A) is caused by bending vibration of the N-H bond。1461cm^-1The absorption peaks of (a) are generated by C-H bending vibration and C-N stretching vibration. 1251cm^-1The absorption peak of (a) is a stretching vibration absorption peak of a C-O bond in an O ═ C-O structure. 1043cm^-1The absorption peak of (2) is attributed to the C-O bond stretching vibration in the C-OH structure. 2200cm^-1No distinct absorption peaks appear to the left or right, indicating that the NCO groups have reacted to completion. From the above analysis, the product contains urethane groups, hydroxyl groups, and no NCO groups.

Example 2

The production method of the 75D/72F environment-friendly PET/PTT bi-component elastic fiber filament comprises the following steps: respectively synthesizing PET slices and PTT slices, finally drawing out the slices through a double-screw machine, and slicing two components to endow the two components on one yarn. The specific process is as follows:

a) PET slice manufacturing process

(1) Pretreatment: the PET bottle is primarily screened and primarily cleaned, then is crushed into 18 mm PET bottle flakes, and then is dried after passing through a cleaning assembly line, and finally is subjected to color separation through infrared color separation equipment.

(2) Pulping: the chopped and dried PET fragments are pressed into an esterification kettle, the hyperbranched polyurethane (the mass of the hyperbranched polyurethane accounts for 0.05 percent of that of the PET fragments) prepared in the example 1 is added under the protection of nitrogen at normal pressure, the mixture is stirred and reacted for 2 hours at 200 ℃, and generated water is condensed and discharged to obtain clear and transparent terylene liquid with the viscosity of 0.4mPa & s.

(3) Slicing: the liquid is injected into a reaction double-screw rod, the reaction temperature is 150 ℃, underwater granulation, drying and packaging are carried out, and PET slices with the molecular weight of 400KDa, the average grain diameter of 7 microns and the viscosity of 0.6mPa & s are obtained.

b) PTT slice preparation process

(1) Pulping: fully crushing the corn straws, and mixing the crushed starchy raw materials with stirring water to form a starch solution.

(2) Saccharification and fermentation: saccharifying enzyme (Aspergillus oryzae) is added into the starch solution to prepare a saccharified solution. This step hydrolyzes the alpha-1, 4 and alpha-1, 6 glycosidic linkages of polysaccharides (starch, glycogen, etc.) to glucose.

(3) Aerobic fermentation: adding 5g/L saccharifying enzyme (Aspergillus oryzae) into the saccharified solution, wherein the fermentation container has constant temperature control function, maintaining the fermentation temperature at 42-45 deg.C for 48 hr, and stirring every 4 hr for 5 min to hydrolyze alpha-1, 4 and alpha-1, 6 glycosidic bond of polysaccharide (starch, glycogen, etc.) to obtain glycerol fermentation liquid.

(4) Anaerobic fermentation: filtering the glycerol fermentation liquor, filtering the filtrate, transferring the filtrate into another fermentation tank, adding Klebsiella pneumoniae (5g/L), maintaining the fermentation temperature at 42 ℃ for 72 hours, and performing anaerobic fermentation to obtain 1, 3-propanediol liquid.

(5) Esterification reaction: terephthalic acid and the 1, 3-propanediol are mixed according to the ratio of 2:1.2, an acrylate thickener TH5000 (Shanghai Dajin chemical Co., Ltd.) is added, the mixture is stirred and reacted for 3 hours at 170 ℃, and the generated water is condensed and discharged, so that a PTT clear transparent liquid with the viscosity of 0.7 mPas and high viscosity is obtained.

(6) Slicing: the liquid is injected into a reaction double-screw rod, the reaction temperature is 200 ℃, underwater granulation, drying and packaging are carried out, and PTT slices with the molecular weight of 700KDa, the average grain diameter of 7 microns and the viscosity of 1.2mPa & s are obtained.

c) Spinning process

Extruding the prepared PTT slices in a screw extruder, and heating and melting at 250 ℃; the PET chips prepared above were melted at the same temperature to a PET melt. And the PET melt is mixed with the PTT melt fed through the PTT melt distribution pipe in the PET melt distribution pipe, and the weight ratio of the PET melt to the PTT melt is 60: and 40, producing according to the prior art to obtain a semi-finished product of the pre-oriented yarn barrel, and then performing elastic display treatment by a drafting winder to obtain a finished product of the modified PET/PTT elastic fiber. In the drawing and winding process, the drawing multiple is as follows: the stretching ratio of the high-speed silk stretching process is 1.5-1.7; the drawing speed is 1000-1200 MPM; the winding speed is 8000-10000 RPM; the twist is 10-15.

The cross section appearance of the finished fiber product is similar to that of common bi-component fiber; according to the national GB/T14460-2015 polyester filament appearance detection standard, the dry breaking strength is 4.64 CN/dtex; wet breaking strength 2.35 CN/dtex; the whiteness is 85; the oil content was 0.32%.

Example 3

1. The weaving process comprises the following steps:

1.1 device parameters

2+4 common double-sided rounding machine;

machine number 24 needles/25.4 mm;

barrel diameter 863.6mm (34 ");

lane number 72F.

1.2 raw material specification

The scheme is as follows: 18.0tex (75D/72F) polyester filament, 8.33tex/F (50D/32F) PTT/PET bicomponent environment-friendly filament (made in example 2).

The existing product is as follows: 18.0tex (75D/72F) polyester filaments (content 70%), 8.33tex/F (50D/32F) PTT/PET bicomponent staple filaments (product purchased from Korea Xiaoxing Co., Ltd.) were contained 30%.

1.3 knitting needle arrangement

The knitting needle arrangement is arranged according to the method for knitting interlock texture (interlock fabric).

I.e. the dial is arranged in order AB and the needle cylinder is arranged in order BA. Adopts cotton wool for alignment.

1.4 triangular arrangement

The triangular arrangement is shown in the table below, with a total of 10F being a complete structure. Wherein, the 2 nd, 4 th, 5 th, 7 th, 9 th and 10 th polyester filament yarns and the 1 st, 3 rd, 6 th and 8 th bicomponent environment-friendly PET/PTT filaments.

TABLE 1 triangular arrangement

2. Fabric parameters are as follows:

blank cloth gram weight 225g/m²And the width is 1560 mm.

3. And (3) physical index testing:

the high-hydrophilicity filament yarn product prepared by the invention and the fabric of the existing product are tested according to the following indexes:

TABLE 2 comparison of elasticity index of fabrics in the examples of the invention

TABLE 3 comparison of hydrophilicity indices of fabrics of the examples of the present invention

Test items	Wicking height	Drip diffusion	Water absorption rate
				This scheme	35cm	2s	400％
Existing products	15cm	10s	50％

Remarking: textile moisture absorption (drip diffusion time, wicking height, water absorption according to GB/T21655.1-2008 test method).

According to the invention, a Biolin contact angle instrument is adopted to test the contact angle of the fabric, and the test results of the fabric of the bi-component fiber (the mass ratio of the hyperbranched polyurethane compound is 0.05%) prepared by hyperbranched polyurethane and the common bi-component PET/PTT fiber fabric in the embodiment of the invention are shown in figure 3.

The data show that compared with the existing PET/PBT product, the product of the invention is obviously superior to the existing product in the wearing comfort index and the moisture absorption (dripping water diffusion time, wicking height, water absorption and water contact angle) index, and the defect of poor hydrophilic moisture absorption of the existing PET/PTT bi-component product is obviously improved. Meanwhile, the elastic index (elongation and recovery rate) of the product is superior to that of the existing product.

Example 4

Bicomponent fibers were prepared as in example 2, except that the proportion by mass of the hyperbranched polyurethane compound was 0.1%.

According to the method of example 3, a fabric was prepared. The water contact angle results are shown in FIG. 4.

Example 5

Bicomponent fibers were prepared as in example 2, except that the proportion by mass of the hyperbranched polyurethane compound was 0.2%.

According to the method of example 3, a fabric was prepared. The water contact angle results are shown in FIG. 5.

In the process of preparing the PET/PTT elastic fiber, the hyperbranched polyurethane is added, so that the elasticity of the bi-component yarn is superior to that of the conventional PET/PTT fiber, the moisture regain of the bi-component yarn can be improved, and the bi-component yarn has better hydrophilic hygroscopicity. Furthermore, in the specific embodiment of the invention, the PET slice raw material can be from a waste recovered PET plastic bottle, and the PTT slice raw material can be from bio-based fermentation, so that the consumption of petroleum resources can be reduced, and the environment protection is facilitated.

The above description and examples are intended to illustrate the scope of the invention, but are not intended to limit the scope of the invention. Modifications, equivalents and other improvements which may occur to those skilled in the art and which may be made to the embodiments of the invention or portions thereof through a reasonable analysis, inference or limited experimentation, in light of the common general knowledge, the common general knowledge in the art and/or the prior art, are intended to be within the scope of the invention.

Claims

1. The modified PET/PTT elastic fiber is characterized in that the raw materials for preparing the modified PET/PTT elastic fiber comprise hyperbranched polyurethane;

the hyperbranched polyurethane is prepared by the following steps:

mixing the polyurethane intermediate, the first-generation hydroxyl-terminated hyperbranched polymer and a hydrophilic chain extender, and then reacting to obtain hyperbranched polyurethane; the hydrophilic chain extender is dimethylolpropionic acid, dimethylolbutyric acid and N, N-dihydroxyethyl-2-aminopropionic acid; the viscosity of the hyperbranched polyurethane at 30 ℃ is 1880-1890 mPa · s.

2. The modified PET/PTT elastic fiber according to claim 1, wherein the hydroxyl value of the hyperbranched polyurethane is 390 to 399 mgKOH/g.

3. A method for preparing the modified PET/PTT elastic fiber of claim 1 or 2, comprising the steps of:

4. The method for preparing the modified PET/PTT elastic fiber according to claim 3, wherein the PET raw material of the PET chips is derived from waste recycled PET plastic bottles; the PTT component of the PTT slice is formed by esterification and polymerization reaction of 1, 3-propanediol and terephthalic acid, and the 1, 3-propanediol is prepared by a biological fermentation method.

5. The method for preparing the modified PET/PTT elastic fiber according to claim 4, wherein the PET chips are prepared by the following steps:

mixing the PET fragments and hydrophilic substances, and stirring at 100-270 ℃ for reaction to obtain PET reaction liquid;

6. The method for preparing the modified PET/PTT elastic fiber according to claim 5, wherein the PTT chips are prepared by the following steps:

7. The preparation method of the modified PET/PTT elastic fiber according to claim 6, wherein the melting temperature of the PET chips is 200-250 ℃, and the melting temperature of the PTT chips is 230-270 ℃; the mass ratio of the PET melt to the PTT melt is 40-60: 40-60.

8. The preparation method of the modified PET/PTT elastic fiber according to any one of claims 3 to 7, wherein the modified PET/PTT elastic fiber further comprises an auxiliary agent component, and the auxiliary agent is selected from one or more of an antistatic agent, an antioxidant and a lubricant.

9. A fabric is characterized by comprising the modified PET/PTT elastic fiber obtained by the preparation method of any one of claims 3-8.