A bio-based side-by-side composite elastic fiber and its preparation method

Abstract

The present invention belongs to the technical field of polymers and discloses a bio-based side-by-side composite elastic fiber, which comprises a first fiber and a second fiber; the first fiber is made of bio-based polytrimethylene terephthalate modified by diamine monomers; the second fiber is made of bio-based polytrimethylene terephthalate with polytrimethylene glycol segments modified by diamine monomers. The fiber uses two kinds of polytrimethylene terephthalate for side-by-side composite spinning. The comfort softness, resilience and breaking strength of the fiber are improved through the polytrimethylene glycol segments. The compatibility, comfort softness, resilience and breaking strength of the two fibers are further improved through diamine modification, and a fiber material with excellent performance is obtained. At the same time, the present invention also provides a preparation method of the fiber material.

Description

Technical Field

[0001] The present invention relates to the field of polymers, and particularly to a bio-based side-by-side composite elastic fiber and a preparation method thereof. Background Art

[0002] Bicomponent side-by-side composite fibers are a type of elastic fibers with a three-dimensional crimp structure. They were first proposed by Sisson and Moorbead. Kanebo Ltd. of Japan began research in 1962 and industrialized it in 1965. Bicomponent side-by-side composite fibers are composed of two polymers with good compatibility and large differences in thermal shrinkage properties. Such fibers include polyester, polyamide, or polyolefin types, but polyester types with relatively high cost performance have a better market. A representative product of this type is T-400 Lycra developed by DuPont, also known as "EasyFit Lycra", which is a bicomponent side-by-side composite fiber composed of PET / PTT. Compared with "Lycra", this helical three-dimensional crimp elastic fiber has many unique features: short production process flow, high fiber strength, low modulus, good heat resistance, no loss of elasticity due to dyeing and processing, resistance to sunlight, and resistance to chlorine bleaching. However, due to the differences in the melting spinning temperature, dyeing temperature, and dyeing pressure of the PET and PTT components in the T400 side-by-side composite fiber, the fabric made has a relatively rough hand feeling and high energy consumption.

[0003] Bio-based polymer materials use renewable resources as the main raw materials. While reducing the consumption of fossil resources, they also reduce the environmental impact of the production and use processes of fossil-based polymer materials. They are the key development objects of current polymer materials and an important way to achieve "carbon neutrality" and develop "low-carbon economy", with great research value and social and economic benefits.

[0004] The technical problem to be solved in this case is how to further improve the comfort softness, resilience, and breaking strength of bicomponent side-by-side composite fibers. Summary of the Invention

[0005] The purpose of the present invention is to provide a bio-based side-by-side composite elastic fiber. This fiber uses two poly(trimethylene terephthalate)s for side-by-side composite spinning. The comfort softness, resilience, and breaking strength of the fiber are improved through the poly(tetramethylene ether glycol) chain segment, and the compatibility, comfort softness, resilience, and breaking strength of the two fibers are further improved through diamine modification, resulting in a fiber material with excellent performance.

[0006] Meanwhile, the present invention also provides a preparation method of this fiber material.

[0007] To achieve the above purpose, the present application discloses:

[0008] A bio-based side-by-side composite elastic fiber, comprising a first fiber and a second fiber; the first fiber is made of a bio-based poly(trimethylene terephthalate) modified with a diamine monomer; the second fiber is made of a bio-based poly(trimethylene terephthalate) having a poly(tetramethylene ether glycol) segment modified with a diamine monomer.

[0009] In the above-mentioned bio-based side-by-side composite elastic fiber, the diamine is one or more of 1,6-hexanediamine, 1,10-decanediamine, and 1,12-diaminododecane.

[0010] In the above-mentioned bio-based side-by-side composite elastic fiber, the bio-based poly(trimethylene terephthalate) modified with a diamine monomer is made of the following monomers:

[0011] Terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, and diamine;

[0012] The molar ratio of terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, and diamine is: 1:1.2 - 1.3:0.02 - 0.06.

[0013] In the above-mentioned bio-based side-by-side composite elastic fiber, the bio-based poly(trimethylene terephthalate) having a poly(tetramethylene ether glycol) segment modified with a diamine monomer is made of the following monomers:

[0014] Terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, diamine, and bio-based poly(tetramethylene ether glycol);

[0015] The molar ratio of terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, and diamine is: 1:1.2 - 1.3:0.02 - 0.06;

[0016] The bio-based poly(tetramethylene ether glycol) accounts for 5 - 50% of the mass of the bio-based poly(trimethylene terephthalate) having a poly(tetramethylene ether glycol) segment modified with a diamine monomer.

[0017] In the above-mentioned bio-based side-by-side composite elastic fiber, the preparation method of the bio-based poly(trimethylene terephthalate) modified with a diamine monomer is as follows: First, carry out an ester exchange reaction on terephthalic acid or dimethyl terephthalate, bio-based PDO, and diamine, and then carry out a polycondensation reaction;

[0018] The temperature of the ester exchange reaction is 190 - 240°C, the reaction time is 1 - 2 h, the temperature of the polycondensation reaction is 250 - 260°C, the reaction time is 3 - 4 h, and in the polycondensation stage, gradually reduce the pressure until the reaction ends;

[0019] The preparation method of the bio-based poly(trimethylene terephthalate) modified with the diamine monomer and having a poly(trimethylene glycol) segment is as follows: First, carry out an ester exchange reaction on terephthalic acid or dimethyl terephthalate, bio-based PDO, and the diamine, and then add bio-based poly(trimethylene glycol) for polycondensation reaction;

[0020] The temperature of the ester exchange reaction is 190-240°C, and the reaction time is 1-2 h. The temperature of the polycondensation reaction is 250-260°C, and the reaction time is 3-4 h. In the polycondensation stage, gradually reduce the pressure until the reaction ends.

[0021] In the above-mentioned bio-based side-by-side composite elastic fiber, the catalyst used in the ester exchange reaction and the catalyst used in the polycondensation reaction are each independently one or a mixture of two or more of tetrabutyl titanate, isopropyl titanate, tetraethyl titanate, magnesium acetate, zinc acetate, manganese acetate, antimony trioxide, and ethylene glycol antimonate, and the addition amount is 0.01-0.1% of the total mass of the reactants;

[0022] An antioxidant is also added in the polycondensation reaction; the antioxidant is one of trimethyl phosphate, triphenyl phosphite, Irganox1010, Irganox168, and Irganox245, and the addition amount is 0.01-0.1% of the total mass of the reactants.

[0023] In the above-mentioned bio-based side-by-side composite elastic fiber, the number average molecular weight of the bio-based poly(trimethylene glycol) is 1000-3000 g / mol.

[0024] In the above-mentioned bio-based side-by-side composite elastic fiber, the mass ratio of the first fiber to the second fiber is 30:70-70:30.

[0025] In the above-mentioned bio-based side-by-side composite elastic fiber, the intrinsic viscosity of the bio-based poly(trimethylene terephthalate) modified with the diamine monomer is 0.87-0.92 dL / g; the intrinsic viscosity of the bio-based poly(trimethylene terephthalate) modified with the diamine monomer and having a poly(trimethylene glycol) segment is 0.90-1.40 dL / g.

[0026] Meanwhile, the present invention also discloses a preparation method of the above-mentioned bio-based side-by-side composite elastic fiber. The bio-based poly(trimethylene terephthalate) modified with the diamine monomer and the bio-based poly(trimethylene terephthalate) modified with the diamine monomer and having a poly(trimethylene glycol) segment are dried in a drum oven. The pre-crystallization temperature is 120-140°C, and the pre-crystallization time is 6-10 h. After drying, the water content of the polyester is less than 70 ppm, and side-by-side composite spinning is carried out by a melt spinning machine according to the mass ratio of the two components.

[0027] This application has at least the following beneficial effects:

[0028] In the bio-based side-by-side composite elastic fiber provided by the present invention, both of the two fibers are PTT-based polymers, with excellent interfacial compatibility. At the same time, the differences in melt spinning temperature, dyeing temperature and dyeing pressure are small, and a large shrinkage difference is still maintained between the two components. Therefore, the prepared side-by-side composite elastic fiber has high breaking strength, high resilience, comfortable and soft hand feeling, and good fluffiness.

[0029] In the bio-based side-by-side composite elastic fiber provided by the present invention, diamine monomers are introduced into both of the two fibers, and the introduction of amide units forms hydrogen bonds between the polyester molecular chains, effectively improving the mechanical properties of the polymer. Specific Embodiments

[0030] The following will combine the embodiments of the present invention to clearly and completely describe the present invention. In the description of the present invention, it should be noted that for those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0031] Example 1

[0032] (1) Preparation of Component I

[0033] Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and the esterification catalyst tetrabutyl titanate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.26:0.04, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Nitrogen is introduced into the reactor. After replacing the air in the reactor, the pressure is increased to 2 bar. Under the stirring speed of 100 r / min, the temperature is raised to 240 °C and reacted for 1 h. When no more liquid flows out of the reactor, the pressure in the reactor is reduced to atmospheric pressure. Add the polycondensation catalyst tetrabutyl titanate at 0.01% of the total mass and Irganox 1010 at 0.01% of the total mass, stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa, and react at 250 °C for 3 h.

[0034] The intrinsic viscosity of the prepared Component I is 0.88 dL / g.

[0035] (2) Preparation of Component II

[0036] (2.1) Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and the esterification catalyst tetrabutyl titanate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.26:0.04, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Nitrogen is introduced into the reactor. After replacing the air in the reactor, the pressure is increased to 2 bar. Under the stirring speed of 100 r / min, the temperature is raised to 240 °C and reacted for 1 h.

[0037] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure. Add PO3G (molecular weight 2000 g / mol) accounting for 5% of the total mass, tetrabutyl titanate as the polycondensation catalyst accounting for 0.01% of the total mass, and Irganox1010 accounting for 0.01% of the total mass. React at a temperature of 240 °C and a stirring speed of 100 r / min for 2 h.

[0038] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reaction kettle to atmospheric pressure, slowly heat up from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0039] The intrinsic viscosity of the prepared Component II is 1.02 dL / g.

[0040] (3) Pretreatment

[0041] Place the prepared Component I and Component II raw materials in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0042] (4) Melt coextrusion spinning of the pretreated Component I and Component II is carried out at a mass ratio of 70:30. Specifically, each of the two components is melt-extruded into a melt using a twin-screw extruder. The two melts enter the coextrusion spinning assembly simultaneously and are extruded by the side-by-side coextrusion spinneret. They are cooled by side air blowing and the spinning channel, oiled by an oiling roller, and the as-spun fibers are wound at a high speed by a winding machine. Then, after drawing and heat setting and winding into filaments, the bio-based side-by-side coextrusion elastic fibers can be obtained.

[0043] Among them, the process parameters of the coextrusion spinning include: the screw temperature of Component I is 260 °C, the metering pump temperature is 265 °C, the screw temperature of Component II is 260 °C, the metering pump temperature is 265 °C, the spinning assembly temperature is 265 °C, the pump supply rate of the metering pump is 40 ml / min, the number of holes in the spinneret is 24, and the hole diameter is 0.25 mm; the winding speed is 2000 m / min, the drawing ratio is 2 times, the temperature of the first drawing and heat roller is 70 °C, and the temperature of the second drawing and heat roller is 120 °C.

[0044] The breaking strength of the prepared bio-based side-by-side coextrusion elastic fibers is 3.4 cN / dtex, and the breaking elongation is 50%. At a state of an elongation of 10%, the elastic recovery rate is 90%.

[0045] Example 2

[0046] (1) Preparation of Component I

[0047] Put terephthalic acid, bio-based PDO, 1,10-decanediamine, and the esterification catalyst zinc acetate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,10-decanediamine is 1:1.26:0.04, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize it to 2 bar. At a stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h. When no more liquid flows out of the reactor, reduce the pressure in the reactor to atmospheric pressure. Add zinc acetate as the polycondensation catalyst at 0.01% of the total mass and Irganox 1010 at 0.01% of the total mass. Stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0048] The intrinsic viscosity of the prepared Component I is 0.90 dL / g.

[0049] (2) Preparation of Component II

[0050] (2.1) Put terephthalic acid, bio-based PDO, 1,10-decanediamine, and the esterification catalyst zinc acetate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,10-decanediamine is 1:1.26:0.04, and the esterification catalyst zinc acetate is 0.01% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize it to 2 bar. At a stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h;

[0051] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure. Add PO3G (molecular weight 2000 g / mol) at 10% of the total mass, zinc acetate as the polycondensation catalyst at 0.01% of the total mass, and Irganox 1010 at 0.01% of the total mass. React at a temperature of 240 °C and a stirring speed of 100 r / min for 2 h.

[0052] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reactor to atmospheric pressure, slowly raise the temperature from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0053] The intrinsic viscosity of the prepared copolymer of Component II is 1.10 dL / g.

[0054] (3) Pretreatment

[0055] Place the prepared raw materials of Component I and Component II in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the dried polyester is less than 70 ppm.

[0056] (4) The pretreated Component I and Component II are melt-compounded and spun side by side at a mass ratio of 50:50. Specifically, the two components are each melt-extruded into a melt using a twin-screw extruder. The two melts simultaneously enter the composite spinning assembly and are extruded through a side-by-side composite spinneret. They are cooled by side blowing and in the spinning duct, oiled with an oiling agent by an oiling roller, and then high-speed wound by a winding machine to obtain a nascent fiber. After drawing and heat setting and winding into filaments, bio-based side-by-side composite elastic fibers can be obtained.

[0057] Among them, the process parameters of the side-by-side composite spinning include that the screw temperature of Component I is 260 °C, the temperature of the metering pump is 265 °C, the screw temperature of Component II is 255 °C, the temperature of the metering pump is 260 °C, the temperature of the spinning assembly is 265 °C, the pump supply of the metering pump is 50 ml / min, the number of holes in the spinneret is 24, the hole diameter is 0.25 mm, the winding speed is 2000 m / min, the draw ratio is 3 times, the temperature of the first drawing hot roller is 70 °C, and the temperature of the second drawing hot roller is 120 °C.

[0058] The breaking strength of the prepared bio-based side-by-side composite elastic fiber is 3.1 cN / dtex, and the breaking elongation is 62%. Under the state of an elongation of 10%, the elastic recovery rate is 92%.

[0059] Example 3

[0060] (1) Preparation of Component I

[0061] Dimethyl terephthalate, bio-based PDO, 1,6-hexanediamine, and the transesterification catalyst tetrabutyl titanate are put into a polymerization reactor. The molar ratio of dimethyl terephthalate, PDO, and 1,6-hexanediamine is 1:1.26:0.04, and the transesterification catalyst tetrabutyl titanate is 0.1% of the total mass. Nitrogen is introduced into the reactor. After replacing the air in the reactor, the pressure is increased to 2 bar. Under a stirring speed of 100 r / min, the temperature is raised to 190 °C and reacted for 1 h until no more liquid flows out of the reactor. The pressure in the reactor is reduced to atmospheric pressure, and the polycondensation catalysts tetrabutyl titanate and zinc acetate are added at 0.1% of the total mass, and trimethyl phosphate is added at 0.1% of the total mass. Stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa and react at 250 °C for 3 h.

[0062] The intrinsic viscosity of the prepared Component I is 0.91 dL / g.

[0063] (2) Preparation of Component II

[0064] (2.1) Dimethyl terephthalate, bio-based PDO, 1,6-hexanediamine, and the transesterification catalyst tetrabutyl titanate were charged into a polymerization reactor. The molar ratio of dimethyl terephthalate, PDO, and 1,6-hexanediamine was 1:1.26:0.04, and the transesterification catalyst tetrabutyl titanate was 0.1% of the total mass. Nitrogen was introduced into the reactor. After displacing the air in the reactor, the pressure was increased to 2 bar. At a stirring speed of 100 r / min, the temperature was raised to 190 °C and reacted for 1 h.

[0065] (2.2) After the reaction in step (2.1) was completed, the pressure was adjusted to atmospheric pressure. PO3G (molecular weight 1000 g / mol) added accounted for 10% of the total mass, the polycondensation catalysts tetrabutyl titanate and zinc acetate were 0.1% of the total mass, and trimethyl phosphate was 0.1% of the total mass. The reaction was carried out at a temperature of 210 °C and a stirring speed of 100 r / min for 2 h.

[0066] (2.3) After the reaction in step (2.2) was completed, the pressure in the reaction kettle was reduced to atmospheric pressure, and the temperature was slowly raised from 210 °C to 250 °C while the pressure was slowly reduced to 50 Pa. The reaction was carried out at 250 °C for 3 h.

[0067] The intrinsic viscosity of the prepared Component II was 1.05 dL / g.

[0068] (3) Pretreatment

[0069] The prepared Component I and Component II raw materials were placed in a drum oven for drying. The pre-crystallization temperature was 120 °C, the pre-crystallization time was 6 h, and the water content of the polyester after drying was less than 70 ppm.

[0070] (4) The pretreated Component I and Component II were melt-conjugate spun at a mass ratio of 50:50. Specifically, the two components were each melt-extruded into a melt using a twin-screw extruder. The two melts simultaneously entered the conjugate spinning assembly and were extruded by the conjugate spinneret plate therein. They were cooled by side blowing and the spinning channel, oiled by an oiling roller, and high-speed wound by a winding machine to obtain a nascent fiber. After drawing and heat setting and winding into filaments, the bio-based conjugate elastic fiber could be obtained.

[0071] Among them, the process parameters of conjugate spinning included that the screw temperature of Component I was 260 °C, the temperature of the metering pump was 265 °C, the screw temperature of Component II was 250 °C, the temperature of the metering pump was 260 °C, the temperature of the spinning assembly was 265 °C, the pump supply rate of the metering pump was 40 ml / min, the number of holes in the spinneret plate was 24, the hole diameter was 0.25 mm, the winding speed was 2000 m / min, the drawing ratio was 2 times, the temperature of the first drawing hot roller was 70 °C, and the temperature of the second drawing hot roller was 120 °C.

[0072] The prepared bio-based side-by-side composite elastic fiber has a breaking strength of 3.1 cN / dtex and an elongation at break of 58%. At an elongation of 10%, the elastic recovery rate is 91%.

[0073] Example 4

[0074] (1) Preparation of Component I

[0075] Dimethyl terephthalate, bio-based PDO, 1,12-diaminododecane, and the transesterification catalyst antimony trioxide were put into a polymerization reactor. The molar ratio of dimethyl terephthalate, PDO, and 1,12-diaminododecane was 1:1.26:0.04, and the transesterification catalyst antimony trioxide was 0.01% of the total mass. Nitrogen was introduced into the reactor. After displacing the air in the reactor, the pressure was increased to 2 bar. At a stirring speed of 100 r / min, the temperature was raised to 190 °C and reacted for 1 h. When no more liquid flowed out of the reactor, the pressure in the reactor was reduced to atmospheric pressure. The added polycondensation catalyst antimony trioxide was 0.01% of the total mass, and triphenyl phosphite was 0.01% of the total mass. Stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0076] The prepared bio-based PTT had an intrinsic viscosity of 0.89 dL / g.

[0077] (2) Preparation of Component II

[0078] (2.1) Dimethyl terephthalate, bio-based PDO, 1,12-diaminododecane, and the transesterification catalyst antimony trioxide were put into a polymerization reactor. The molar ratio of dimethyl terephthalate, PDO, and 1,12-diaminododecane was 1:1.26:0.04, and the transesterification catalyst antimony trioxide was 0.01% of the total mass. Nitrogen was introduced into the reactor. After displacing the air in the reactor, the pressure was increased to 2 bar. At a stirring speed of 100 r / min, the temperature was raised to 190 °C and reacted for 1 h.

[0079] (2.2) After the reaction in step (2.1) was completed, the pressure was adjusted to atmospheric pressure. The added PO3G (molecular weight 1000 g / mol) accounted for 10% of the total mass, the polycondensation catalyst antimony trioxide was 0.01% of the total mass, and triphenyl phosphite was 0.01% of the total mass. React at a temperature of 210 °C and a stirring speed of 100 r / min for 2 h.

[0080] (2.3) After the reaction in step (2.2) was completed, the pressure in the reactor was reduced to atmospheric pressure, and the temperature was slowly raised from 210 °C to 250 °C, while slowly reducing the pressure to 50 Pa. React at 250 °C for 3 h.

[0081] The intrinsic viscosity of the prepared Component II is 1.09 dL / g.

[0082] (3) Pretreatment

[0083] Place the prepared Component I and Component II raw materials in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0084] (4) Melt co-extrusion composite spinning of the pretreated Component I and Component II is carried out at a mass ratio of 50:50. Specifically, the two components are each melt-extruded into a melt using a twin-screw extruder. The two melts enter the composite spinning assembly simultaneously and are extruded by the co-extrusion type composite spinneret. They are cooled by side blowing and the spinning channel, oiled by an oiling roller, and the as-spun fibers are wound at high speed by a winding machine. After drawing and heat setting and winding into filaments, the bio-based co-extrusion composite elastic fibers can be obtained.

[0085] Among them, the process parameters of the co-extrusion composite spinning include: the screw temperature of Component I is 260 °C, the temperature of the metering pump is 260 °C, the screw temperature of Component II is 255 °C, the temperature of the metering pump is 260 °C, the temperature of the spinning assembly is 260 °C, the pump supply of the metering pump is 40 ml / min, the number of holes in the spinneret is 24, the hole diameter is 0.25 mm, the winding speed is 2000 m / min, the drawing ratio is 2 times, the temperature of the first drawing hot roller is 70 °C, and the temperature of the second drawing hot roller is 120 °C.

[0086] The breaking strength of the prepared bio-based co-extrusion composite elastic fibers is 3.0 cN / dtex, and the breaking elongation is 63%. At a state of 10% elongation, the elastic recovery rate is 92%.

[0087] Example 5

[0088] (1) Preparation of Component I

[0089] Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and the esterification catalyst tetrabutyl titanate into a polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.26:0.04, and the esterification catalyst tetrabutyl titanate is 0.1% of the total mass. Nitrogen is introduced into the reactor. After replacing the air in the reactor, the pressure is increased to 2 bar. Under a stirring speed of 100 r / min, the temperature is raised to 240 °C and reacted for 1 h until no more liquid flows out of the reactor. Then the pressure in the reactor is reduced to atmospheric pressure. Add the polycondensation catalyst tetrabutyl titanate at 0.1% of the total mass and Irganox1010 at 0.1% of the total mass, stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa and react at 250 °C for 3 h.

[0090] The intrinsic viscosity of the prepared Component I is 0.88 dL / g.

[0091] (2) Preparation of Component II

[0092] (2.1) Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and the esterification catalyst tetrabutyl titanate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.26:0.04, and the tetrabutyl titanate as the esterification catalyst is 0.1% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize it to 2 bar. Under the stirring speed of 100 r / min, heat it up to 240 °C and react for 1 h.

[0093] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure. Add PO3G (molecular weight 2000 g / mol) accounting for 20% of the total mass, tetrabutyl titanate as the polycondensation catalyst accounting for 0.1% of the total mass, and Irganox1010 accounting for 0.1% of the total mass. React at 240 °C under the condition of a stirring speed of 100 r / min for 2 h.

[0094] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reactor to atmospheric pressure, slowly heat up from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0095] The intrinsic viscosity of the prepared Component II is 1.15 dL / g.

[0096] (3) Pretreatment

[0097] Place the prepared Component I and Component II raw materials in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0098] (4) Melt co-extrusion spinning of the pretreated Component I and Component II is carried out at a mass ratio of 70:30. Specifically, the two components are melted and extruded into melts by a twin-screw extruder respectively. The two melts enter the co-extrusion spinning assembly at the same time and are extruded by the side-by-side co-extrusion spinneret. They are cooled by side blowing and the spinning duct, oiled by an oiling roller, and the as-spun fibers are obtained by high-speed winding with a winding machine. Then, after drawing and heat setting and winding into filaments, the bio-based side-by-side co-extrusion elastic fibers can be obtained.

[0099] Among them, the process parameters of the side-by-side composite spinning include: the screw temperature of component I is 260 °C, the temperature of the metering pump is 265 °C, the screw temperature of component II is 250 °C, the temperature of the metering pump is 260 °C, the temperature of the spinning pack is 265 °C, the pump supply rate of the metering pump is 50 ml / min, the number of holes in the spinneret is 24, the hole diameter is 0.25 mm, the winding speed is 2000 m / min, the draw ratio is 2 times, the temperature of the first drawing hot roller is 70 °C, and the temperature of the second drawing hot roller is 120 °C.

[0100] The breaking strength of the prepared bio-based side-by-side composite elastic fiber is 2.8 cN / dtex, and the breaking elongation is 46%. Under the condition of an elongation of 10%, the elastic recovery rate is 93%.

[0101] Example 6

[0102] (1) Preparation of Component I

[0103] Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and the esterification catalyst tetrabutyl titanate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.26:0.04, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Pass nitrogen into the reactor. After replacing the air in the reactor, pressurize it to 2 bar. Under the stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h. When no more liquid flows out of the reactor, reduce the pressure in the reactor to atmospheric pressure. Add the polycondensation catalyst tetrabutyl titanate, which is 0.01% of the total mass, and Irganox 1010, which is 0.1% of the total mass. Stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0104] The intrinsic viscosity of the prepared component I is 0.90 dL / g.

[0105] (2) Preparation of Component II

[0106] (2.1) Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and the esterification catalyst tetrabutyl titanate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.26:0.04, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Pass nitrogen into the reactor. After replacing the air in the reactor, pressurize it to 2 bar. Under the stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h.

[0107] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure, add PO3G (molecular weight 2000 g / mol) accounting for 30% of the total mass, tetrabutyl titanate as the polycondensation catalyst accounting for 0.01% of the total mass, and Irganox1010 accounting for 0.01% of the total mass. React at 240 °C with a stirring speed of 100 r / min for 2 h.

[0108] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reaction kettle to atmospheric pressure, slowly heat up from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0109] The intrinsic viscosity of the prepared Component II is 1.25 dL / g.

[0110] (3) Pretreatment

[0111] Place the prepared Component I and Component II raw materials in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0112] (4) Melt co-extrusion composite spinning of the pretreated Component I and Component II is carried out at a mass ratio of 70:30. Specifically, melt and extrude the two components separately with a twin-screw extruder to obtain melts. The two melts enter the composite spinning assembly at the same time and are extruded by the co-extrusion type composite spinneret. They are cooled by side blowing and the spinning channel, oiled by an oiling roller, and the nascent fibers are obtained by high-speed winding with a winding machine. Then, after drawing and heat setting and winding into filaments, the bio-based co-extrusion composite elastic fiber can be obtained.

[0113] Among them, the process parameters of the co-extrusion composite spinning include: the screw temperature of Component I is 260 °C, the temperature of the metering pump is 265 °C, the screw temperature of Component II is 250 °C, the temperature of the metering pump is 260 °C, the temperature of the spinning assembly is 265 °C, the pump supply rate of the metering pump is 50 ml / min, the number of holes in the spinneret is 24, the hole diameter is 0.25 mm, the winding speed is 2000 m / min, the drawing ratio is 2 times, the temperature of the first drawing hot roller is 70 °C, and the temperature of the second drawing hot roller is 120 °C.

[0114] The breaking strength of the prepared bio-based co-extrusion composite elastic fiber is 2.6 cN / dtex, and the breaking elongation is 36%. At a state of an elongation of 10%, the elastic recovery rate is 96%.

[0115] Example 7

[0116] (1) Preparation of Component I

[0117] Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and tetrabutyl titanate as the esterification catalyst into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.24:0.06, and the tetrabutyl titanate as the esterification catalyst is 0.01% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize it to 2 bar. Under the stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h. When no more liquid flows out of the reactor, reduce the pressure in the reactor to atmospheric pressure. Add tetrabutyl titanate as the polycondensation catalyst at 0.01% of the total mass and Irganox1010 at 0.01% of the total mass, stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa, and react at 250 °C for 3 h.

[0118] The intrinsic viscosity of the prepared Component I is 0.83 dL / g.

[0119] (2) Preparation of Component II

[0120] (2.1) Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and tetrabutyl titanate as the esterification catalyst into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.24:0.06, and the tetrabutyl titanate as the esterification catalyst is 0.01% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize it to 2 bar. Under the stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h.

[0121] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure. Add PO3G (molecular weight 2000 g / mol) at 5% of the total mass, tetrabutyl titanate as the polycondensation catalyst at 0.01% of the total mass, and Irganox1010 at 0.01% of the total mass. React at 240 °C under the condition of a stirring speed of 100 r / min for 2 h.

[0122] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reactor to atmospheric pressure, slowly raise the temperature from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa, and react at 250 °C for 3 h.

[0123] The intrinsic viscosity of the prepared Component II is 0.96 dL / g.

[0124] (3) Pretreatment

[0125] Place the prepared Component I and Component II raw materials in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0126] (4) The pretreated Component I and Component II are melt co-spun in a mass ratio of 70:30. Specifically, the two components are each melt-extruded into a melt using a twin-screw extruder. The two melts simultaneously enter the composite spinning assembly and are extruded from the side-by-side composite spinneret. They are cooled by side blowing and the spinning duct, oiled with an oiling agent by an oiling roller, and high-speed wound by a winding machine to obtain as-spun fibers. Then, they are drawn and heat-set and wound into filaments to obtain bio-based side-by-side composite elastic fibers.

[0127] Among them, the process parameters of the side-by-side composite spinning include: the screw temperature of Component I is 260 °C, the metering pump temperature is 265 °C, the screw temperature of Component II is 255 °C, the metering pump temperature is 260 °C, the spinning assembly temperature is 265 °C, the pump supply rate of the metering pump is 40 ml / min, the number of holes in the spinneret is 24, and the hole diameter is 0.25 mm; the winding speed is 2000 m / min, the draw ratio is 2 times, the temperature of the first draw hot roller is 70 °C, and the temperature of the second draw hot roller is 120 °C.

[0128] The breaking strength of the obtained bio-based side-by-side composite elastic fiber is 2.8 cN / dtex, and the breaking elongation is 42%. At a state of an elongation of 10%, the elastic recovery rate is 91%.

[0129] Example 8

[0130] (1) Preparation of Component I

[0131] Terephthalic acid, bio-based PDO, 1,6-hexanediamine, and the esterification catalyst tetrabutyl titanate are put into a polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.28:0.02, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Nitrogen is introduced into the reactor. After replacing the air in the reactor, the pressure is increased to 2 bar. At a stirring speed of 100 r / min, the temperature is raised to 240 °C and reacted for 1 h. When no more liquid flows out of the reactor, the pressure in the reactor is reduced to atmospheric pressure. Then, 0.01% of the total mass of the polycondensation catalyst tetrabutyl titanate and 0.01% of the total mass of Irganox1010 are added, and stirred for 30 min. The temperature is gradually raised to 250 °C, and at the same time, the pressure is slowly reduced to 50 Pa and reacted at 250 °C for 3 h.

[0132] The intrinsic viscosity of the prepared Component I is 0.79 dL / g.

[0133] (2) Preparation of Component II

[0134] (2.1) Put terephthalic acid, bio-based PDO, 1,6-hexanediamine, and tetrabutyl titanate as the esterification catalyst into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,6-hexanediamine is 1:1.28:0.02, and the tetrabutyl titanate as the esterification catalyst is 0.01% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize it to 2 bar. Under the stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h.

[0135] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure. Add 5% of PO3G (molecular weight 2000 g / mol) based on the total mass, 0.01% of tetrabutyl titanate as the polycondensation catalyst based on the total mass, and 0.01% of Irganox1010 based on the total mass. React at 240 °C under the condition of a stirring speed of 100 r / min for 2 h.

[0136] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reactor to atmospheric pressure. Slowly raise the temperature from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0137] The intrinsic viscosity of the prepared Component II is 0.94 dL / g.

[0138] (3) Pretreatment

[0139] Place the prepared Component I and Component II raw materials in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0140] (4) Melt co-extrusion composite spinning of the pretreated Component I and Component II is carried out at a mass ratio of 70:30. Specifically, melt-extrude the two components into melts respectively using a twin-screw extruder. The two melts enter the composite spinning assembly at the same time and are extruded by the co-extrusion type composite spinneret. They are cooled by side blowing and the spinning duct, oiled by an oiling roller, and high-speed wound by a winding machine to obtain the as-spun fiber. Then, through drawing and heat setting and winding into filaments, the bio-based co-extrusion composite elastic fiber can be obtained.

[0141] Among them, the process parameters of co-extrusion composite spinning include that the screw temperature of Component I is 255 °C, the metering pump temperature is 260 °C, the screw temperature of Component II is 250 °C, the metering pump temperature is 260 °C, the spinning assembly temperature is 260 °C, the pump supply rate of the metering pump is 40 ml / min, the number of holes in the spinneret is 24, and the hole diameter is 0.25 mm; the winding speed is 2000 m / min, the drawing ratio is 2 times, the temperature of the first drawing and heat roller is 70 °C, and the temperature of the second drawing and heat roller is 120 °C.

[0142] The prepared bio-based side-by-side composite elastic fiber has a breaking strength of 2.6 cN / dtex and an elongation at break of 37%. At an elongation of 10%, the elastic recovery rate is 91%.

[0143] Comparative Example 1

[0144] (1) Preparation of bio-based PTT

[0145] Put terephthalic acid, bio-based PDO, and the esterification catalyst zinc acetate into the polymerization reactor, where the molar ratio of terephthalic acid to PDO is 1:1.30, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Pass nitrogen into the reactor, replace the air in the reactor, then pressurize to 2 bar, and at a stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h. After no more liquid flows out of the reactor, reduce the pressure in the reactor to atmospheric pressure, add the polycondensation catalyst zinc acetate at 0.01% of the total mass and Irganox1010 at 0.01% of the total mass, stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa, and react at 250 °C for 3 h.

[0146] The intrinsic viscosity of the prepared bio-based PTT is 0.76 dL / g.

[0147] (2) Preparation of bio-based PTT-PO3G

[0148] (2.1) Put terephthalic acid, bio-based PDO, and the esterification catalyst zinc acetate into the polymerization reactor, where the molar ratio of terephthalic acid to PDO is 1:1.30, and the esterification catalyst zinc acetate is 0.01% of the total mass. Pass nitrogen into the reactor, replace the air in the reactor, then pressurize to 2 bar, and at a stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h;

[0149] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure, add PO3G (molecular weight 2000 g / mol) accounting for 10% of the total mass, the polycondensation catalyst zinc acetate at 0.01% of the total mass, and Irganox1010 at 0.01% of the total mass, and react at a temperature of 240 °C and a stirring speed of 100 r / min for 2 h.

[0150] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reactor to atmospheric pressure, slowly raise the temperature from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0151] The intrinsic viscosity of the prepared bio-based PTT-PO3G copolymer is 0.88 dL / g.

[0152] The prepared bio - based PTT and bio - based PTT - PO3G raw materials were placed in a drum oven for drying. The pre - crystallization temperature was 120 °C, the pre - crystallization time was 6 h, and the water content of the polyester after drying was less than 70 ppm.

[0153] (4) The pretreated bio - based PTT and bio - based PTT - PO3G were melt - spun in a side - by - side composite manner at a mass ratio of 50:50. Specifically, the two components were each melt - extruded into a melt using a twin - screw extruder. The two melts entered the composite spinning assembly simultaneously and were extruded by a side - by - side type composite spinneret. They were cooled by side - blowing air and in the spinning channel, oiled by an oiling roller, and then high - speed wound by a winding machine to obtain a nascent fiber. After drawing and heat - setting and winding into filaments, bio - based side - by - side composite elastic fibers could be obtained.

[0154] Among them, the process parameters of the side - by - side composite spinning included: the screw temperature of bio - based PTT was 250 °C, the temperature of the metering pump was 255 °C, the screw temperature of bio - based PTT - PO3G was 250 °C, the temperature of the metering pump was 260 °C, the temperature of the spinning assembly was 260 °C, the pump supply of the metering pump was 50 ml / min, the number of holes in the spinneret was 24, the hole diameter was 0.25 mm, the winding speed was 2000 m / min, the drawing ratio was 3 times, the temperature of the first drawing hot roller was 70 °C, and the temperature of the second drawing hot roller was 120 °C.

[0155] The breaking strength of the prepared bio - based side - by - side composite elastic fiber was 2.0 cN / dtex, and the breaking elongation rate was 54%. At a state of 10% elongation, the elastic recovery rate was 80%.

[0156] Comparative Example 2

[0157] (1) Preparation of bio - based PTT

[0158] Terephthalic acid, bio - based PDO, and the esterification catalyst zinc acetate were put into a polymerization reactor. The molar ratio of terephthalic acid to PDO was 1:1.30, and the esterification catalyst tetrabutyl titanate was 0.01% of the total mass. Nitrogen was introduced into the reactor. After replacing the air in the reactor, the pressure was increased to 2 bar. At a stirring speed of 100 r / min, the temperature was raised to 240 °C and reacted for 1 h. After no more liquid flowed out of the reactor, the pressure in the reactor was reduced to atmospheric pressure. The polycondensation catalyst zinc acetate added was 0.01% of the total mass, and Irganox1010 was 0.01% of the total mass. Stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa and react at 250 °C for 3 h.

[0159] The intrinsic viscosity of the prepared bio - based PTT was 0.76 dL / g.

[0160] (2) Preparation of Component II

[0161] (2.1) Put terephthalic acid, bio-based PDO, 1,10-decanediamine, and the esterification catalyst zinc acetate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,10-decanediamine is 1:1.26:0.04, and the esterification catalyst zinc acetate accounts for 0.01% of the total mass. Introduce nitrogen into the reactor. After displacing the air in the reactor, pressurize it to 2 bar. Under the stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h;

[0162] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure. Add PO3G (molecular weight 2000 g / mol) accounting for 10% of the total mass, the polycondensation catalyst zinc acetate accounting for 0.01% of the total mass, and Irganox1010 accounting for 0.01% of the total mass. React at 240 °C under the condition of a stirring speed of 100 r / min for 2 h.

[0163] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reactor to atmospheric pressure. Slowly raise the temperature from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0164] The intrinsic viscosity of the prepared component II copolymer is 1.10 dL / g.

[0165] (3) Pretreatment

[0166] Place the prepared bio-based PTT and component II raw materials in a drum oven for drying. The pre-crystallization temperature is 120 °C, the pre-crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0167] (4) Melt co-extrusion composite spinning of the pretreated bio-based PTT and component II is carried out at a mass ratio of 50:50. Specifically, the two components are each melt-extruded into a melt using a twin-screw extruder. The two melts enter the composite spinning assembly simultaneously and are extruded by the co-extrusion type composite spinneret. They are cooled by side blowing and the spinning channel, oiled by an oiling roller, and the as-spun fibers are obtained by high-speed winding with a winding machine. Then, after drawing and heat setting and winding into filaments, the bio-based co-extrusion composite elastic fibers can be obtained.

[0168] Among them, the process parameters of the co-extrusion composite spinning include that the screw temperature of bio-based PTT is 250 °C, the temperature of the metering pump is 255 °C, the screw temperature of component II is 255 °C, the temperature of the metering pump is 260 °C, the temperature of the spinning assembly is 265 °C, the pump supply rate of the metering pump is 50 ml / min, the number of holes in the spinneret is 24, the hole diameter is 0.25 mm, the winding speed is 2000 m / min, the drawing ratio is 3 times, the temperature of the first drawing hot roller is 70 °C, and the temperature of the first drawing hot roller is 120 °C.

[0169] The breaking strength of the prepared bio-based side-by-side composite elastic fiber is 2.3 cN / dtex, and the elongation at break is 46%. At an elongation of 10%, the elastic recovery rate is 85%.

[0170] Comparative Example 3

[0171] (1) Preparation of Component I

[0172] Put terephthalic acid, bio-based PDO, 1,10-decanediamine, and the esterification catalyst zinc acetate into the polymerization reactor. The molar ratio of terephthalic acid, PDO, and 1,10-decanediamine is 1:1.26:0.04, and the esterification catalyst tetrabutyl titanate is 0.01% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize to 2 bar. At a stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h. When no more liquid flows out of the reactor, reduce the pressure in the reactor to atmospheric pressure. Add the polycondensation catalyst zinc acetate at 0.01% of the total mass and Irganox1010 at 0.01% of the total mass, stir for 30 min, gradually raise the temperature to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0173] The intrinsic viscosity of the prepared Component I is 0.90 dL / g.

[0174] (2) Preparation of Bio-based PTT-PO3G

[0175] (2.1) Put terephthalic acid, bio-based PDO, and the esterification catalyst zinc acetate into the polymerization reactor. The molar ratio of terephthalic acid and PDO is 1:1.30, and the esterification catalyst zinc acetate is 0.01% of the total mass. Pass nitrogen into the reactor. After displacing the air in the reactor, pressurize to 2 bar. At a stirring speed of 100 r / min, raise the temperature to 240 °C and react for 1 h;

[0176] (2.2) After the reaction in step (2.1) is completed, adjust the pressure to atmospheric pressure. Add PO3G (molecular weight 2000 g / mol) at 10% of the total mass, the polycondensation catalyst zinc acetate at 0.01% of the total mass, and Irganox1010 at 0.01% of the total mass. React at a temperature of 240 °C and a stirring speed of 100 r / min for 2 h.

[0177] (2.3) After the reaction in step (2.2) is completed, reduce the pressure in the reactor to atmospheric pressure, slowly raise the temperature from 240 °C to 250 °C, and at the same time slowly reduce the pressure to 50 Pa. React at 250 °C for 3 h.

[0178] The intrinsic viscosity of the prepared bio-based PTT-PO3G copolymer is 0.88 dL / g.

[0179] (3) Pretreatment

[0180] Place the prepared Component I and the bio - based PTT - PO3G raw material in a drum oven for drying. The pre - crystallization temperature is 120 °C, the pre - crystallization time is 6 h, and the water content of the polyester after drying is less than 70 ppm.

[0181] (4) Melt conjugate spinning of the pretreated Component I and bio - based PTT - PO3G is carried out at a mass ratio of 50:50. Specifically, the two components are respectively melted and extruded into melts by a twin - screw extruder. The two melts enter the conjugate spinning assembly simultaneously and are extruded by the conjugate spinneret plate therein. They are cooled by side blowing and the spinning channel, oiled by an oiling roller, and the as - spun fibers are obtained by high - speed winding with a winding machine. Then, after drawing and heat setting and winding into filaments, the bio - based conjugate elastic fibers can be obtained.

[0182] Among them, the process parameters of conjugate spinning include: the screw temperature of Component I is 260 °C, the temperature of the metering pump is 265 °C, the screw temperature of bio - based PTT - PO3G is 250 °C, the temperature of the metering pump is 260 °C, the temperature of the spinning assembly is 260 °C, the pump supply rate of the metering pump is 50 ml / min, the number of holes on the spinneret plate is 24, the hole diameter is 0.25 mm, the winding speed is 2000 m / min, the drawing ratio is 3 times, the temperature of the first drawing hot roller is 70 °C, and the temperature of the second drawing hot roller is 120 °C.

[0183] The breaking strength of the prepared bio - based conjugate elastic fiber is 2.6 cN / dtex, and the elongation at break is 50%. Under the condition of an elongation of 10%, the elastic recovery rate is 87%.

[0184] Summary:

[0185] It can be seen from Examples 1 to 8 that through the modification with polytrimethylene glycol block and diamine, the breaking strength of the product of the present invention can be maintained above 2.6 cN / dtex, and under the condition of an elongation of 10%, the elastic recovery rate is not less than 90%;

[0186] It can be seen from Comparative Examples 1 to 3 that when either of the two fibers does not use diamine modification, it cannot meet the above - mentioned performance requirements. Among them, when neither of the two fibers uses diamine modification, both the breaking strength and the elastic recovery rate are poor;

[0187] When PTT does not use diamine modification, compared with Comparative Example 1, its performance is slightly enhanced, but it is still inferior to each example;

[0188] When PTT - PO3G does not use diamine modification, the elastic recovery rate is inferior to each example. The difference in breaking strength between it and Example 2 is 0.5 cN / dtex, and the difference in elastic recovery rate is 5%, but it is better than Comparative Example 1 and Comparative Example 2;

[0189] It can be seen that the modification of PTT with diamine is the key to achieving performance improvement. When both types of fibers are modified, a significant improvement in performance can be achieved.

[0190] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

**1. A bio-based bicomponent parallel composite elastic fiber, characterized in that it comprises a first fiber and a second fiber; the first fiber is made of a bio-based polytrimethylene terephthalate modified with a diamine monomer; the second fiber is made of a bio-based polytrimethylene terephthalate modified with a diamine monomer and having a polytrimethylene ether glycol segment; the diamine is one or more of 1,6-hexamethylenediamine, 1,10-decanediamine, and 1,12-diaminododecane; the diamine monomer-modified bio-based polytrimethylene terephthalate is made from the following monomers: terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, and a diamine; the molar ratio of terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, and diamine is 1:1.2–1.3:0.02–0.06; the diamine monomer-modified bio-based polytrimethylene terephthalate having a polytrimethylene ether glycol segment is made from the following monomers: terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, a diamine, and bio-based polytrimethylene ether glycol; the molar ratio of terephthalic acid or dimethyl terephthalate, bio-based 1,3-propanediol, and diamine is 1:1.2–1.3:0.02–0.06; the bio-based polytrimethylene ether glycol accounts for 5–50% by mass of the diamine monomer-modified bio-based polytrimethylene terephthalate having a polytrimethylene ether glycol segment; the diamine monomer-modified bio-based polytrimethylene terephthalate has an intrinsic viscosity of 0.87–0.92 dL / g; the diamine monomer-modified bio-based polytrimethylene terephthalate having a polytrimethylene ether glycol segment has an intrinsic viscosity of 0.90–1.40 dL / g.****2. The bio-based bicomponent parallel composite elastic fiber according to claim 1, characterized in that the preparation method of the diamine monomer-modified bio-based polytrimethylene terephthalate is as follows: first, carry out a transesterification reaction of terephthalic acid or dimethyl terephthalate, bio-based PDO, and a diamine, followed by a polycondensation reaction; the transesterification reaction temperature is 190–240°C, and the reaction time is 1–2 h; the polycondensation reaction temperature is 250–260°C, and the reaction time is 3–4 h; during the polycondensation stage, the pressure is gradually reduced until the reaction is complete; the preparation method of the diamine monomer-modified bio-based polytrimethylene terephthalate having a polytrimethylene ether glycol segment is as follows: first, carry out a transesterification reaction of terephthalic acid or dimethyl terephthalate, bio-based PDO, and a diamine, then add bio-based polytrimethylene ether glycol to carry out a polycondensation reaction; the transesterification reaction temperature is 190–240°C, and the reaction time is 1–2 h; the polycondensation reaction temperature is 250–260°C, and the reaction time is 3–4 h; during the polycondensation stage, the pressure is gradually reduced until the reaction is complete.****3. The bio-based bicomponent parallel composite elastic fiber according to claim 2, characterized in that the catalyst used for the transesterification reaction and the catalyst used for the polycondensation reaction are each independently one or a mixture of two or more of tetrabutyl titanate, titanium tetraisopropoxide, tetraethyl titanate, magnesium acetate, zinc acetate, manganese acetate, antimony trioxide, and antimony glycolate, added in an amount of 0.01–0.1% of the total mass of the reactants; an antioxidant is also added during the polycondensation reaction; the antioxidant is one of trimethyl phosphate, triphenyl phosphite, Irganox 1010, Irganox 168, and Irganox 245, added in an amount of 0.01–0.1% of the total mass of the reactants.****4. The bio-based bicomponent parallel composite elastic fiber according to claim 1, characterized in that the number-average molecular weight of the bio-based polytrimethylene ether glycol is 1000–3000 g / mol.****5. The bio-based bicomponent parallel composite elastic fiber according to claim 1, characterized in that the mass ratio of the first fiber to the second fiber is 30:70 to 70:30.****6. A method for preparing the bio-based bicomponent parallel composite elastic fiber according to any one of claims 1–5, characterized in that the diamine monomer-modified bio-based polytrimethylene terephthalate and the diamine monomer-modified bio-based polytrimethylene terephthalate having a polytrimethylene ether glycol segment are dried in a tumble dryer oven, with a pre-crystallization temperature of 120–140°C and a pre-crystallization time of 6–10 h, and the moisture content of the dried polyester is less than 70 ppm; then, bicomponent parallel composite spinning is carried out using a melt spinning machine according to the mass ratio of the two components.**