CN107326467A - A kind of black washable polyester fiber and preparation method thereof - Google Patents

Abstract

The present invention relates to textile technology field, specifically, it is related to a kind of black washable polyester fiber, the fastness to washing of the polyester fiber is 4~5 grades, and fracture strength is 3.0~3.5dtex/cN, preferably 3.3~3.4dtex/cN, elongation at break is 20~30%, preferably 25%.Present invention also offers the preparation method of the black washable polyester fiber, using continuous polymerization technique, the inherent viscosity and terminal hydroxyl content of polymer are effectively controlled, the quality of fiber product is stabilized；And using the method cooled after esterification, using corresponding decentralized medium, make and contaminate more uniform on carbon black stain.

Description

A kind of black washable polyester fiber and preparation method thereof

technical field

The invention relates to the technical field of textiles, in particular to a black washable polyester fiber and a preparation method thereof.

Background technique

Polytrimethylene terephthalate (PTT) is a new type of polyester with excellent performance. Its special structure and excellent physical and chemical properties make it widely used in textiles, engineering plastics, films and other fields. Due to the "odd carbon effect" that is different from PET and PBT due to the three methylene groups in the PTT macromolecular chain, the PTT polyester fiber can overcome the rigidity of PET and the flexibility of PBT at the same time, and has both PET and PA Advantages, such as excellent resilience, easy processing, easy dyeing and bulkiness, etc., so it is widely used in clothing, carpets, home textiles and other fields.

In recent years, black poly(trimethylene terephthalate) fiber has become more and more widely used, especially carbon black dyed black poly(trimethylene terephthalate fiber), which has high washing fastness and light aging resistance, and does not need to be dyed like solution dyeing. The production of industrial wastewater is in line with the environmental protection concept of green development, and its demand is also increasing.

At present, the main preparation method of PTT fiber is to use PTT and special black masterbatch to blend and spin. The Chinese patent No. CN103556287A discloses a colored yarn of creep-resistant polyester, which is made of high-viscosity slices of creep-resistant polyester, mixed with black masterbatch, extruded, cooled, oiled, stretched and wound On the one hand, this method has a relatively high cost, and on the other hand, due to some errors in the process of metering and adding black masterbatch, it often leads to a series of problems such as color difference in the final fiber.

There are also some continuous black polyester preparation methods in the prior art. The Chinese patent application number 201420735798.X has developed a set of carbon black grinding and online adding system, and carried out black polyester production on the continuous polyester polycondensation production device. Continuous production. This patent uses water as the dispersion medium, and the prepared carbon black slurry is directly added to the esterified product at a temperature of 250-260°C. The water evaporates, which easily causes the re-agglomeration of carbon black, making the prepared black polyester prone to black spots. , so that the quality of black polyester fiber is still not very satisfactory.

The Chinese patent with the application number 200710118294.8 discloses a method for preparing black polyester chips and black polyester chips, particularly involving the addition of processed carbon black color paste before the esterification process or transesterification reaction to prepare black polyester chips. Ester chips and methods for their preparation. The invention uses ethylene glycol solvent to dissolve carbon black, and prepares carbon black slurry by adding a dispersant through a high-speed emulsifier, adding carbon black slurry before esterification or transesterification, and finally adding a polycondensation catalyst. After heating up to a qualified intrinsic viscosity at 100°C, black polyester chips are obtained from the discharge. Although this method uses ethylene glycol as the dispersion medium of carbon black, the temperature when adding carbon black slurry for esterification is higher than the boiling point of ethylene glycol, which may cause the agglomeration of carbon black, resulting in the production of polyester black. uniform.

In addition, the ordinary black polyester fiber PTT fabric is usually made by dyeing, but the preparation process of this method is complicated, the dyeing is easy to cause environmental pollution, and the dyed fabric has low washing fastness and is easy to fade after washing. And if the black PTT fabric is prepared by spinning with the black masterbatch method, it will easily cause problems such as uneven color and high cost. In order to solve the problems such as uniform color of the black PTT fabric and wash fastness, the present invention is proposed.

Contents of the invention

The present invention aims to provide a black washable polyester fiber and a preparation method thereof. While adopting a continuous polymerization process, the temperature control of the esterification process is optimized, so that the carbon black dye is more uniformly present in the finished fiber, so as to obtain The purpose of black polyester fabric with high washing fastness and uniform color.

To achieve the above object, the present invention specifically adopts the following technical solutions:

A kind of black washable polyester fiber, the washing fastness of the polyester fiber is 4-5 grades, the breaking strength is 3.0-3.5dtex/cN, preferably 3.3-3.4dtex/cN; the elongation at break is 20 ~30%, preferably 25%.

A further scheme of the present invention is: adopt continuous polymerization process to prepare, carry out heat exchange to realize temperature regulation to esterification product in preparation process; Described polyester fiber contains polytrimethylene terephthalate and carbon black, and the weight of carbon black is 1-3wt% of the weight of propylene glycol terephthalate, preferably 1.5-2wt%; the polyester fiber has uniform intrinsic viscosity and terminal carboxyl group content, and the intrinsic viscosity is 1.12-1.18dL/g, preferably 1.15dL/g g; the carboxyl-terminal content is 14-18 mol/t, preferably 17 mol/t; the melting point is 225-235°C.

In the above-mentioned scheme, the polytrimethylene terephthalate (PTT) used is a new type of polyester with excellent performance. Due to the presence of three methylene groups in the PTT macromolecular chain, it is different from PET and PBT in the "odd" "Carbon effect", so that PTT polyester fiber can overcome the rigidity of PET and the flexibility of PBT at the same time, and has the advantages of both PET and PA, such as excellent resilience, easy processability, easy dyeing and bulkiness, etc. It is widely used in textile, engineering plastics, film and other fields.

In the above scheme, the intrinsic viscosity of the black washable polyester fiber is affected by the preparation method and can be stabilized at a fixed value, which improves the quality stability of the polyester fiber product in the same batch, and also benefits from the stability of the carboxyl-terminal content. The same preparation method keeps the color of the polyester fiber uniform and does not gradually deepen with the production process. Compared with similar polyester products made by ordinary dyeing methods commonly used in the prior art, it has higher color fastness to soaping.

The present invention also provides a method for preparing black washable polyester fibers, which adopts a continuous polymerization process. The preparation method includes material preparation, esterification, carbon black dye preparation, mixing, polycondensation and fiber formation, specifically including the following steps:

(1) Terephthalic acid and propylene glycol are mixed and beaten according to a certain molar ratio, and a catalyst is added simultaneously to obtain a slurry;

(2) Esterifying the slurry in step (1), controlling the esterification temperature at 250-255° C., the esterification rate reaches 90-96%, and obtaining an esterification product;

(3) carbon black is added propylene glycol to make medium solution, carries out ball milling, obtains carbon black dyeing agent, controls the add-on of carbon black dyeing agent simultaneously;

(4) the esterification product of step (2) is mixed with the carbon black dyeing agent of step (3) to obtain mixed raw materials;

(5) polycondensation reaction is carried out to the mixed raw material of step (4), control reaction time, temperature and vacuum tightness obtain black propylene glycol terephthalate polymer;

(6) process the black propylene glycol terephthalate polymer of step (5) to obtain black washable polyester fiber;

The step (2) also includes performing heat exchange on the esterification product to lower the temperature of the esterification product.

According to the above method, the temperature drop is from 250-255°C to 190-195°C.

According to the above method, the medium solution described in the step (3) is a medium solution with a concentration of 20 to 50% prepared by adding carbon black to propylene glycol; step (3) also includes adding polypropylene glycol to the medium solution for uniform dispersion, which The added amount is 2-4wt% of the medium solution, preferably 2-3wt%.

In the above method, the continuous polymerization process refers to the continuous preparation of a black polytrimethylene terephthalate raw material, and continuous direct spinning to prepare the black PTT polyester fiber process, the process is in the polyester continuous On the polymerization spinning production line, a new type of continuous polymerization and continuous spinning equipment with one esterification kettle, one pre-shrinkage kettle and one final polycondensation kettle (three-pot short process) is used to prepare black PTT fiber continuously. The preparation process has the advantages of low energy consumption, large output, uniform color, good quality stability, no black spots, and easy large-scale industrial production.

In the above method, the esterification in step (2) takes place in the esterification reactor, and the heat exchange process takes place in a heat exchanger at about 0.2 to 0.25 meters from the outlet of the esterification reactor, and the heat exchanger Connected with the esterification kettle, it contains a heat medium coil, and the heat medium circulates in the coil to cool down, so that the inlet temperature of the heat medium entering the heat exchanger is controlled at 160-170°C, and the outlet temperature is controlled at 190-195°C. Lower the temperature of the esterification product at 250-255°C to 190-195°C to adapt to the boiling point of the carbon black dye medium solution.

In the above-mentioned method, take polypropylene glycol as tensio-active agent, the propylene glycol that dissolves carbon black is that medium solution makes carbon black dyeing agent, the boiling point of described medium solution is corresponding to the temperature after the esterification thing cools down, and carbon black dyeing agent and After the esterification products are mixed, the carbon black is evenly released in the esterification products, so that the color of the product produced by the subsequent polycondensation reaction is uniform.

According to the above method, the molecular weight of the polypropylene glycol in step (3) is 800-2000, preferably 1000.

In the above-mentioned method, polypropylene glycol is a kind of surfactant, and it can disperse carbon black more evenly in propylene glycol solution, forms stable dispersion solution, does not appear sedimentation, and the molecular weight of polypropylene glycol has also influenced the dispersibility of carbon black simultaneously . Compared with water commonly used in the prior art as the dispersion medium, propylene glycol not only improves the boiling point of the medium solution, but also facilitates the uniform distribution of carbon black, and simultaneously because the propylene glycol solution is more easily dispersed in the esterification product propylene glycol terephthalate , so that the carbon black dye is more uniformly dispersed in the esterification product, and the carbon black dye and the esterification product are more easily combined in the polycondensation process.

The polycondensation reaction described in step (5) includes a pre-condensation reaction and a final polycondensation reaction, the temperature of the pre-condensation reaction is 265-270°C, the time is 20-40min, and the vacuum is 1.0-1.5KPa; the final polycondensation reaction The temperature is 270-272°C, the time is 20-40min, and the vacuum is 100-200Pa.

In the above method, the pre-condensation reaction and the final polycondensation reaction occur in the corresponding pre-condensation tank and the final polycondensation tank respectively, and the viscosity of the polymer melt is monitored online during the final polycondensation process. When the intrinsic viscosity is 1.15dL/ When g, discharge.

According to the above method, the concentration of the medium solution in step (3) is 20-30%.

According to the above method, the molar ratio of terephthalic acid to propylene glycol in step (1) is 1:1.20-1.25; the mixing and beating time in step (1) is 30-50 minutes, preferably 35-40 minutes.

According to the above method, the catalyst in step (1) is antimony propylene glycol, and the amount of catalyst added is 0.2-0.5 wt%, preferably 0.25-0.35 wt%, of the mass of terephthalic acid.

According to the above method, the esterification temperature in step (2) is 253-255° C., and the esterification rate is 91-93%.

In the above method, the esterification rate is controlled so that the polycondensation product can easily reach an intrinsic viscosity of 1.15dL/g. If the esterification rate is low, it will easily lead to low molecular weight of the polycondensation product. If the esterification rate is too high, the esterification reaction time will be reduced. Lengthened, leading to an increase in the carboxyl group content of the polycondensation product. It is easy to affect the quality of the fiber.

According to the above method, the grinding time of the ball milling in the step (3) is 20-40 minutes.

The specific steps of the preparation method provided by the invention include:

(1) Put terephthalic acid and propylene glycol into the beating kettle according to the molar ratio of 1:1.20 to 1.25, and at the same time add a catalyst for beating together. The catalyst is propylene glycol antimony, and its addition amount is 0.2% of the quality of terephthalic acid. -0.5 wt%, preferably 0.25-0.35 wt%. After beating for 30-50 minutes, preferably 35-40 minutes, put it into the slurry supply tank for standby;

(2) Pump the slurry obtained in step (1) into the esterification reactor by a metering pump, and carry out the esterification reaction. Control the esterification temperature at 250-255°C, preferably 253-255°C, and control the flow rate so that After the reactor, the esterification rate reaches 90-96%, preferably 91-93%. Pump the esterification product into the pipeline, and cool it down to 190-195°C through a heat exchanger, wherein the heat exchanger is connected to the esterification kettle at a position of about 0.2-0.25 meters from the outlet of the esterification kettle, and the heat exchange The device contains a heat medium coil, through which the cooling heat medium is circulated to cool down, so that the inlet temperature of the heat medium entering the heat exchanger is controlled at 160-170°C, and the outlet temperature is controlled at 190-195°C, and the esterification product is cooled through the heat exchanger After that, through the syringe;

(3) adding carbon black to the concentration that propylene glycol is mixed with is the medium solution of 20～50%, and preferred concentration is 20～30%; Then add the polypropylene glycol that molecular weight is 800～2000 (preferred molecular weight is 1000) and carry out uniform dispersion, its The addition amount is 2-4wt% of the medium solution, preferably 2-3wt%, and then ground in a ball mill for 20-40 minutes, pumped into a storage tank, and then metered into a pipeline by a syringe. Controlling the addition of carbon black is 1-3% of the total reactant mass, preferably 1.5-2%;

(4) fully mix the esterification product through the syringe in the step (2) and the carbon black dye in the step (3) in a static mixer to obtain a mixed raw material, and then carry out the next step polycondensation reaction;

(5) Control the mixed raw materials to slowly enter the pre-condensation reactor, control the time for 20-40 minutes, control the temperature to 265-270 °C, control the vacuum degree to 1.0-1.5KPa; then enter the final polycondensation tank, control the time for 20-40 minutes, control When the temperature reaches 270-272°C, the vacuum degree is controlled at 100-200Pa. After the online detection point, when the melt in the final polycondensation process reaches an intrinsic viscosity of 1.15dL/g, the material is discharged;

(6) Carry out underwater pelletizing to the discharge of step (5), and make black PTT granule through drying; Or directly feed discharge into screw rod and spin, make black PTT fiber.

The beneficial effects of the present invention are:

1. The present invention provides a kind of black washable polyester fiber, which has higher washing fastness than similar products in the prior art, and has uniform color and no blemishes;

2. The present invention also provides a preparation method of black washable polyester fiber, which lowers the temperature of the esterified product after the esterification reaction, so that the dispersion medium with carbon black will not evaporate instantly due to high temperature, and avoid excessive evaporation due to rapid evaporation. The resulting agglomeration of carbon black dyes leads to the problem of uneven black color;

3. in the preparation method of the black washable polyester fiber that the present invention also provides, adopted the propylene glycol solution that dissolves polypropylene glycol in the carbon black dyeing agent, improved the boiling point of medium solution, to adapt to the temperature after the esterification, simultaneously It also increases the compatibility of the medium solution and the esterification product, and is more conducive to the combination of carbon black and polycondensate in the polycondensation reaction.

Description of drawings

Fig. 1 is a schematic flow chart of the preparation process of the black washable polyester fiber of the present invention.

detailed description.

The following are specific embodiments of the present invention, and the described examples are for further describing the present invention rather than limiting the present invention.

Example 1

In this embodiment, as shown in Figure 1, a daily output of 5 tons of small flexible modified polyester continuous polyester polycondensation production equipment is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.20, and propylene glycol antimony catalyst accounting for 0.2wt% of terephthalic acid as raw materials, pump it into the supply tank after beating for 35 minutes, and pump it into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out and controlling the esterification reaction temperature at 252°C, the esterification rate is 93%, after the esterification is completed, it is pumped into a heat exchanger, and the temperature is lowered to 195°C;

(3) adding carbon black to the concentration that propylene glycol is mixed with is the medium solution of 30%; Adding molecular weight in the medium solution is the polypropylene glycol of 1600 to carry out uniform dispersion, and its add-on is 4wt% of medium solution, grinds 40 through ball mill again After 10 minutes, the esterification product added from the heat exchanger was metered by a syringe, and the addition of carbon black was controlled to be 1.5wt% of the total reactant quality;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, the pre-condensation reactor controls the reaction temperature at 270°C, the reaction time is 30 minutes, and the vacuum pressure is controlled at 1.2KPa; For 35 minutes, the vacuum pressure was controlled at 100-200 Pa, the intrinsic viscosity of the prepared PTT was always 1.15 g/dl, and the melting point of the polymer was 235° C.

The quality of the product is stable, and the carboxyl group content is also stable at 17mol/t. It can be directly spun to produce black polyester fibers with a fiber breaking strength of 3.3dtex/cN and a breaking elongation of 25%, which can be directly used for black polyester In the preparation of textiles, the prepared textiles do not need to go through the subsequent dyeing process. They are woven from fibers into fabrics. After soaping, their wash fastness can reach level 4, and the fibers have uniform color and no blemishes.

Example 2

In this embodiment, as shown in Figure 1, a daily output of 5 tons of small flexible modified polyester continuous polyester polycondensation production equipment is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.25, and propylene glycol antimony catalyst accounting for 0.35wt% of terephthalic acid as raw materials, pump into the supply tank after beating for 50 minutes, and pump into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out and controlling the esterification reaction temperature at 255°C, the esterification rate is 93%, after the esterification is completed, it is pumped into a heat exchanger, and the temperature is lowered to 192°C;

(3) adding carbon black to the concentration that propylene glycol is mixed with is 20% medium solution; Adding molecular weight in medium solution is the polypropylene glycol of 800 to carry out uniform dispersion, and its add-on is 3wt% of medium solution, grinds 20 through ball mill again After 10 minutes, add the esterification product from the heat exchanger by syringe metering, the addition of controlling carbon black is 2wt% of total reactant quality;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, and the pre-condensation reactor controls the reaction temperature at 265°C, the reaction time is 35 minutes, and the vacuum pressure is controlled at 1.5KPa; For 40 minutes, the vacuum pressure was controlled at 100-200Pa, the intrinsic viscosity of the prepared PTT was always 1.18g/dl, and the melting point of the polymer was 228°C.

The quality of the product is stable, and the carboxyl-terminal content is also stable at 18mol/t. By spinning directly, black polyester fibers with a fiber breaking strength of 3.4dtex/cN and a breaking elongation of 28% can be spun, which can be directly used for black polyester In the preparation of textiles, the prepared textiles do not need to go through the subsequent dyeing process. They are woven from fibers into fabrics. After soaping, their wash fastness can reach level 4, and the fibers have uniform color and no blemishes.

Example 3

In this embodiment, as shown in Figure 1, a daily output of 5 tons of small flexible modified polyester continuous polyester polycondensation production equipment is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.22, and propylene glycol antimony catalyst accounting for 0.25wt% of terephthalic acid as raw materials, pump into the supply tank after beating for 40 minutes, and pump into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out the esterification reaction temperature is controlled at 253 DEG C, and the esterification rate is 91%, and after the esterification is completed, it is pumped into a heat exchanger, and the temperature is lowered to 190 DEG C;

(3) adding carbon black to the concentration that propylene glycol is mixed with is the medium solution of 25%; Adding the polypropylene glycol that molecular weight is 2000 to carry out uniform dispersion in medium solution again, its add-on is 2wt% of medium solution, grinds through ball mill again 30 After 10 minutes, meter the esterification product from the heat exchanger by a syringe, and control the addition of carbon black to be 1wt% of the total reactant quality;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, the pre-condensation reactor controls the reaction temperature at 266°C, the reaction time is 40 minutes, and the vacuum pressure is controlled at 1.4KPa; For 20 minutes, the vacuum pressure was controlled at 100-200 Pa, the intrinsic viscosity of the prepared PTT was always 1.17 g/dl, and the melting point of the polymer was 231° C.

The quality of the product is stable, and the carboxyl-terminal content is also stable at 20mol/t. By spinning directly, black polyester fibers with a fiber breaking strength of 3.5dtex/cN and a breaking elongation of 24% can be spun, which can be directly used for black polyester For the preparation of textiles, the prepared textiles do not need to go through the subsequent dyeing process, and are woven from fibers into fabrics. After soaping, the wash fastness can reach level 5, and the fibers have uniform color and no blemishes.

Example 4

In this embodiment, as shown in Figure 1, a daily output of 5 tons of small flexible modified polyester continuous polyester polycondensation production equipment is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.23, and propylene glycol antimony catalyst accounting for 0.5wt% of terephthalic acid as raw materials, pump into the supply tank after beating for 30 minutes, and pump into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out and controlling the esterification reaction temperature at 250° C., the esterification rate is 96%, and after the esterification is completed, it is pumped into a heat exchanger, and the temperature is lowered to 193° C.;

(3) adding carbon black to the concentration that propylene glycol is mixed with is the medium solution of 28%; Adding molecular weight in the medium solution is the polypropylene glycol of 1500 to carry out uniform dispersion, and its add-on is 4wt% of medium solution, grinds through ball mill again 35 After 10 minutes, add the esterification product from the heat exchanger by syringe metering, the addition of controlling carbon black is 3wt% of total reactant quality;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, the pre-condensation reactor controls the reaction temperature at 268°C, the reaction time is 20 minutes, and the vacuum pressure is controlled at 1.0KPa; For 30 minutes, the vacuum pressure was controlled at 100-200 Pa, the intrinsic viscosity of the prepared PTT was always 1.12 g/dl, and the melting point of the polymer was 225°C.

The quality of the product is stable, and the carboxyl-terminal content is also stable at 14mol/t. By spinning directly, black polyester fibers with a fiber breaking strength of 3.0dtex/cN and a breaking elongation of 20% can be spun, which can be directly used for black polyester In the preparation of textiles, the prepared textiles do not need to go through the subsequent dyeing process. They are woven from fibers into fabrics. After soaping, their wash fastness can reach level 4, and the fibers have uniform color and no blemishes.

Example 5

In this embodiment, as shown in Figure 1, a daily output of 5 tons of small flexible modified polyester continuous polyester polycondensation production equipment is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.20, and propylene glycol antimony catalyst accounting for 0.2wt% of terephthalic acid as raw materials, pump it into the supply tank after beating for 35 minutes, and pump it into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out and controlling the esterification reaction temperature at 252°C, the esterification rate is 93%, after the esterification is completed, it is pumped into a heat exchanger, and the temperature is lowered to 195°C;

(3) adding carbon black to the concentration that propylene glycol is mixed with is the medium solution of 30%; Adding the polypropylene glycol that molecular weight is 1000 to carry out uniform dispersion in medium solution again, its add-on is 4wt% of medium solution, grinds through ball mill again 40 After 10 minutes, the esterification product added from the heat exchanger was metered by a syringe, and the addition of carbon black was controlled to be 1.5wt% of the total reactant quality;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, the pre-condensation reactor controls the reaction temperature at 270°C, the reaction time is 30 minutes, and the vacuum pressure is controlled at 1.2KPa; For 35 minutes, the vacuum pressure was controlled at 100-200 Pa, the intrinsic viscosity of the prepared PTT was always 1.15 g/dl, and the melting point of the polymer was 235° C.

The quality of the product is stable, and the carboxyl-terminal content is also stable at 17mol/t. By spinning directly, black polyester fibers with a fiber breaking strength of 3.4dtex/cN and a breaking elongation of 22% can be spun, which can be directly used for black polyester For the preparation of textiles, the prepared textiles do not need to go through the subsequent dyeing process, and are woven from fibers into fabrics. After soaping, the wash fastness can reach level 5, and the fibers have uniform color and no blemishes.

Comparative example 1

In this embodiment, a small flexible modified polyester continuous polyester polycondensation production device with a daily output of 5 tons is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.20, and propylene glycol antimony catalyst accounting for 0.2wt% of terephthalic acid as raw materials, pump it into the supply tank after beating for 35 minutes, and pump it into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out the esterification reaction temperature is controlled at 252 ℃, and the esterification rate is 93%, obtains the esterification product;

(3) adding carbon black to the concentration that propylene glycol is mixed with is the medium solution of 30%; Adding the polypropylene glycol that molecular weight is 1000 to carry out uniform dispersion in medium solution again, its add-on is 4wt% of medium solution, grinds through ball mill again 40 After 10 minutes, the esterification product added from the heat exchanger was metered by a syringe, and the addition of carbon black was controlled to be 1.5wt% of the total reactant quality;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, the pre-shrinkage reactor controls the reaction temperature at 270°C, the reaction time is 30 minutes, and the vacuum pressure is controlled at 1.2KPa; Minutes, the vacuum pressure is controlled at 100-200Pa, the intrinsic viscosity of the prepared PTT is always 1.15g/dl, and the melting point of the polymer is 235°C.

The carboxyl group content of the product is stable at 17mol/t, and it can be spun directly to weave black polyester fibers with a fiber breaking strength of 3.3dtex/cN and a breaking elongation of 25%, which can be directly used in the preparation of black polyester textiles , the prepared textiles do not need to go through the subsequent dyeing process, the fabric is woven from the fiber, and after soaping, its wash fastness is grade 3, and the fiber color is unevenly distributed and has black spots.

Comparative example 2

In this embodiment, a small flexible modified polyester continuous polyester polycondensation production device with a daily output of 5 tons is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.20, and propylene glycol antimony catalyst accounting for 0.2wt% of terephthalic acid as raw materials, pump it into the supply tank after beating for 35 minutes, and pump it into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out and controlling the esterification reaction temperature at 252°C, the esterification rate is 93%, after the esterification is completed, it is pumped into a heat exchanger, and the temperature is lowered to 195°C;

(3) adding carbon black to propylene glycol solution to form a concentration of 30% carbon black dyeing agent, then after ball mill grinding for 40 minutes, adding the esterification product from the heat exchanger by syringe metering, controlling the addition of carbon black is the total reaction 1.5% by weight of the substance;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, the pre-condensation reactor controls the reaction temperature at 270°C, the reaction time is 30 minutes, and the vacuum pressure is controlled at 1.2KPa; For 35 minutes, the vacuum pressure was controlled at 100-200 Pa, the intrinsic viscosity of the prepared PTT was always 1.15 g/dl, and the melting point of the polymer was 235° C.

The carboxyl group content of the product is stable at 17mol/t, and it can be spun directly to weave black polyester fibers with a fiber breaking strength of 3.2dtex/cN and a breaking elongation of 26%, which can be directly used in the preparation of black polyester textiles , the prepared textile does not need to go through the subsequent dyeing process, the fabric is woven from the fiber, and after soaping, its wash fastness can reach level 3, the fiber color distribution is uneven, and there are a small number of blemishes.

Comparative example 3

In this embodiment, a small flexible modified polyester continuous polyester polycondensation production device with a daily output of 5 tons is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.20, and propylene glycol antimony catalyst accounting for 0.2wt% of terephthalic acid as raw materials, pump it into the supply tank after beating for 35 minutes, and pump it into the esterification tank by a metering pump Kettle for esterification;

(2) Carry out and control the esterification reaction temperature at 252°C, the esterification rate is 93%, after the esterification is completed, it is pumped into a heat exchanger, and the temperature is lowered to 95°C;

(3) adding carbon black to water to form a concentration of 30% carbon black dye, then after ball mill grinding for 40 minutes, adding the esterification product from the heat exchanger by syringe metering, controlling the addition of carbon black to be the total reactant 1.5% by weight of mass;

(4) esterification product and carbon black dyeing agent are mixed uniformly through a static mixer to obtain mixed raw materials;

(5) Put the mixed raw materials into the pre-condensation reactor, the pre-condensation reactor controls the reaction temperature at 270°C, the reaction time is 30 minutes, and the vacuum pressure is controlled at 1.2KPa; For 35 minutes, the vacuum pressure was controlled at 100-200 Pa, the intrinsic viscosity of the prepared PTT was always 1.15 g/dl, and the melting point of the polymer was 235° C.

The quality of the product is unstable, and the black polyester fiber with a breaking strength of 2.0dtex/cN and a breaking elongation of 15% is spun out, which is directly used in the preparation of black polyester textiles, and the prepared textiles do not need to be dyed in the subsequent process , woven from fibers into fabrics, after soaping, its wash fastness is grade 2, the fiber color distribution is uneven, and there are black blemishes.

Comparative example 4

In this embodiment, a small flexible modified polyester continuous polyester polycondensation production device with a daily output of 5 tons is used for production, and the steps are as follows:

(1) Use terephthalic acid and propylene glycol with a molar ratio of 1:1.20, and propylene glycol antimony catalyst accounting for 0.2wt% of terephthalic acid as raw materials, pump it into the supply tank after beating for 35 minutes, and pump it into the esterification tank by a metering pump Kettle for esterification;

(2) Carrying out and controlling the esterification reaction temperature at 252°C, the esterification rate is 93%, after the esterification is completed, pump it into a heat exchanger, lower the temperature to 195°C, and obtain the esterification product;

(3) Put the esterification product into the pre-condensation reactor, the pre-condensation reactor controls the reaction temperature to be 270°C, the reaction time is 30 minutes, and the vacuum pressure is controlled at 1.2KPa; The time is 35 minutes, the vacuum pressure is controlled at 100-200Pa, the intrinsic viscosity of the prepared PTT is always 1.15g/dl, and the melting point of the polymer is 235°C;

(4) The prepared PTT is spun and then dyed to obtain a black polyester fiber product.

The terminal carboxyl group content of the product is stable at 17mol/t, the breaking strength of the woven fiber is 3.2dtex/cN, and the breaking elongation is 22%. And the fiber color is uneven and flawed.

Comparative example 5

In this example, the same ratio of raw materials as in Example 1 is used, but the batch polymerization method is adopted, that is, after each esterification, the material is discharged, and terephthalic acid is continuously added without washing the esterification reactor. It is esterified with propylene glycol monomer, and there is a time interval between the two esterification reactions.

The terminal hydroxyl content of the polyester product prepared according to the batch polymerization method is 17mol/t in the first kettle, and the terminal hydroxyl content in the second kettle becomes 25mol/t; and the intrinsic viscosity of the product in the same kettle is different at different discharge times, The intrinsic viscosity when discharging for 5 minutes was 1.10dL/g, the intrinsic viscosity when discharging for 20 minutes was 1.12dL/g, and the intrinsic viscosity when finishing the discharging for 5 minutes before was 1.15dL/g. As a result, different batches of final fiber products have a large difference in breaking strength and elongation at break, and the quality is unstable, and the color of the product gradually deepens with the production of each kettle, which affects the overall effect of appearance.

The performance parameters and appearance of the products of Examples 1-5 and Comparative Examples 1-5 were analyzed and compared, and the results are shown in Table 1.

In combination with the foregoing embodiments and Table 1, it can be known that the present invention provides a method for continuous polymerization of black washable polyester fibers on the basis of three-pot short-flow polyester continuous polymerization equipment, and adopts a propylene glycol solution in which polypropylene glycol is dissolved As the dispersion medium of carbon black, it can stabilize the quality of polyester products, making them have uniform color, flawless appearance, high washing fastness level, and excellent breaking strength and elongation at break. Can be used for many purposes.

Further, on the basis of Example 1, Comparative Example 1 removed the cooling process of the esterification product, resulting in the final product having a poor appearance compared with Example 1, because the dispersion medium of carbon black was relatively low. Evaporating too fast at high temperature makes the carbon black agglomerate, making the color of the product uneven.

Further, on the basis of Example 1, Comparative Example 2 changed the medium solution in the carbon black dye, removed polypropylene glycol as a solute, and as a result, the wash fastness of the final product decreased, and the color was uneven. The reason for this is that polypropylene glycol plays a key role in binding the carbon black to the polycondensate.

Further, on the basis of Example 1, Comparative Example 3 changed the medium solution in the carbon black dye, used water commonly used in the prior art as the dispersion medium, and correspondingly improved the cooling range of the esterification product so that it It is lower than the boiling point of water, but the effect of the final product is not ideal, and the breaking strength and elongation at break have changed greatly. Although the method of cooling after esterification is adopted, the cooling range is too large, which affects the performance of the polycondensate .

Further, in Comparative Example 4, on the basis of the raw material selection in Example 1, the method of first making fibers and then dyeing in the traditional method was used, and it was found that the wash fastness of the final product was only grade 2, which was far inferior to the method provided by the present invention. Prepared fiber products.

Further, Comparative Example 5 adopted batch polymerization on the basis of the raw material selection in Example 1. Since the discharge of the reactor usually takes a period of time, the characteristics of the copolymer prepared by the same reactor material will often be The viscosity number is not the same, the intrinsic viscosity when discharging for 5 minutes is 1.10dL/g, the intrinsic viscosity when discharging for 20 minutes is 1.12dL/g, and the intrinsic viscosity for 5 minutes before the end of discharging is 1.15dL/g, resulting in The molecular weight of the same reactor material will be different, which will have an adverse effect on subsequent applications. And the continuous polymerization of the present invention is a continuous dynamic operation, so it can be guaranteed that the intrinsic viscosity of the control material is all at 1.15dl/g, and there will be no difference between the same batch of materials; in addition, in the batch polymerization reaction, finish the first After the still reaction, the still will not be washed immediately, but the second still reaction will be carried out immediately. Since there are often a large number of polymers in the first still remaining on the still wall of the first still reaction, these residual polymers will still be in the During the polymerization process of the second tank, the quality of the polymer in the second tank is often lower than that of the first tank due to certain thermal degradation, and the color of the slice is deepened, which is reflected in the index of the slice: the copolymerization of the first tank The carboxyl-terminal content of the product is 17mol/t, and the carboxyl-terminal content of the copolymer in the second kettle is 25mol/t. As the carboxyl-terminal content increases, the slice quality will decrease. However, the carboxyl-terminal content of the modified copolymer prepared by continuous polymerization can be stably controlled at 17 mol/t, which is relatively stable.

The present invention has been described in detail above, its purpose is to allow those skilled in the art to understand the content of the present invention and implement it, and can not limit the scope of protection of the present invention with this, all done according to the spirit of the present invention Equivalent changes or modifications shall fall within the protection scope of the present invention.

Claims (10)

1. a kind of black washable polyester fiber, it is characterised in that

The fastness to washing of the polyester fiber is 4~5 grades；

The fracture strength of the polyester fiber is 3.0~3.5dtex/cN, preferably 3.3~3.4dtex/cN；

The elongation at break of the polyester fiber is 20~30%, preferably 25%.

2. black washable polyester fiber according to claim 1, it is characterised in that

The polyester fiber is prepared using continuous polymerization technique, and carrying out heat exchange to esterification products in preparation process realizes tune Temperature；

The polyester fiber contains PTT and carbon black, and the weight of carbon black is propylene glycol ester terephthalate 1~3wt% of weight, preferably 1.5~2wt%；

The polyester fiber has homogeneous inherent viscosity and content of carboxyl end group；

The inherent viscosity of the polyester fiber is 1.12~1.18dL/g；

The content of carboxyl end group of the polyester fiber is 14~20mol/t；

The fusing point of the polyester fiber is 225~235 DEG C.

3. a kind of preparation method of black washable polyester fiber as claimed in claim 1 or 2, described using continuous polymerization technique Preparation method includes getting the raw materials ready, be esterified, prepared by carbon black stain, mixing, polycondensation and into fiber, it is characterised in that

Also include carrying out heat exchange to esterification products in the esterification, esterification products is cooled.

4. the preparation method of black washable polyester fiber according to claim 3, it is characterised in that the cooling be from 250~255 DEG C are down to 190~195 DEG C.

5. the preparation method of black washable polyester fiber according to claim 3, it is characterised in that the carbon black stain system Standby to include the medium solution for being 20~50% by the concentration that carbon black addition propane diols is configured to, preferred concentration is 20~30%；Institute State carbon black stain and prepare to be additionally included in medium solution and add polypropylene glycol and carry out dispersed, its addition is medium solution 2~4wt%, preferred weight percent is 2~3wt%, and carries out ball milling.

6. the preparation method of black washable polyester fiber according to claim 5, it is characterised in that the polypropylene glycol Molecular weight is 800~2000, preferably 1000.

7. the preparation method of black washable polyester fiber according to claim 3, it is characterised in that the condensation polymerization step bag Prepolymerization reaction and whole polycondensation reaction are included, the temperature of the prepolymerization reaction is 265~270 DEG C, and the time is 20~40min, very Reciprocal of duty cycle is 1.0~1.5KPa；The temperature of the whole polycondensation reaction is 270~272 DEG C, and the time is 20~40min, and vacuum is 100~200Pa.

8. the preparation method of black washable polyester fiber according to claim 3, it is characterised in that

It is described to get the raw materials ready including being 1 by mol ratio:1.20~1.25 terephthalic acid (TPA) and mixed with propylene glycol mashing,

The time of the mixing mashing is 30~50min, preferably 35~40min.

9. the preparation method of the black washable polyester fiber according to claim 3 or 8, it is characterised in that

It is described get the raw materials ready in also include catalyst propane diols antimony, the addition of catalyst for terephthalic acid (TPA) quality 0.2~ 0.5wt%, preferably 0.25~0.35wt%.

10. the preparation method of black washable polyester fiber according to claim 3, it is characterised in that the ester of the esterification It is 253~255 DEG C to change temperature, and esterification yield is 90~96%, and preferably esterification yield is 91~93%.