CN1283690C - Dyeingable dalk coloured copolyester and its preparation method - Google Patents

Abstract

The invention relates to an easy-to-dye dark-colored copolyester and a preparation method thereof. The copolyester is characterized in that it contains the following substances in weight percentage: ethylene terephthalate repeating unit is 35.0-90.0; The propylene glycol formate repeating unit is 5.0-50.0; the polyalkylene glycol with an average molecular weight of 500-10000 is the rest. The preparation method is characterized in that in the presence of titanium-based and/or antimony-based catalysts, two or more diol monomer mixtures are directly esterified with terephthalic acid (TPA), or directly esterified with terephthalic acid Methyl ester (DMT) is transesterified, and the obtained esterified product is subjected to polycondensation reaction with polyalkylene glycol to obtain the product. The preparation method of the invention has reasonable design, is easy to realize industrialized production, and has low production cost; and the prepared copolyester has better dark color dyeing performance.

Description

A kind of dyeable dark copolyester and preparation method thereof

technical field

The invention relates to raw materials for synthetic fibers, in particular to an easy-to-dye dark-color copolyester and a preparation method thereof. The fiber produced by the copolyester has good dark-color dyeing performance.

Background technique

As we all know, conventional polyester fiber cannot be dyed under normal pressure, but can only be dyed under high temperature and high pressure, and it is not easy to dye dark colors. These characteristics not only limit its application in many fields, for example, when it is blended with wool, the high temperature of dyeing will make the wool feel Variation, etc., and the implementation of high temperature and high pressure dyeing has higher requirements for dyeing equipment, which increases production costs virtually. In response to this situation, many companies at home and abroad have successively adopted various methods to modify conventional polyester to improve its dyeing performance. At present, the commonly used method is to add cationic dyeable raw materials. Cationic dyeable polyester (CDP) and cationic dyeable polyester (ECDP) have been developed successively, which solves the problem that PET fibers can only be dyed with disperse dyes or The problem of high temperature and high pressure dyeing. But the preparation method of CDP or ECDP generally is to introduce 5-sodium sulfonate-isophthalate dimethyl (SIPM) or 5-sodium sulfonate-isophthalate ethylene glycol ester (SIPE) in polyester, wherein The sulfonate ion dissociated from the sulfonic acid group (-SO ₃ Na) is easy to form a strong bonding entanglement point with the positron part of the macromolecular chain, which makes the polymer melt easy to coagulate and gel, resulting in The viscosity of the melt increases, and the spinneret is easy to be blocked during spinning, which affects the spinnability.

World Patent WO01/36722, U.S. Patent US6,291,066B1 and US6,454,982B1 all describe a method for preparing polyethylene glycol (PEG) modified polyester, and propose to improve the polyethylene glycol (PEG) modification by adopting polyethylene glycol modification. The dyeing performance of ester, but the addition of PEG introduces a large number of ether bonds into the macromolecular chain, resulting in a significant decrease in the heat resistance and oxidation resistance of polyester, making it very difficult to melt spinning, which further affects deformation and yarn formation. , weaving and fabric finishing and other follow-up processing.

Japanese patent JP2001-192933 mentions a kind of dyeable polyester fiber, which is to solve the problems related to the traditional polyester fiber and textile fabrics containing difficult-to-dye PET raw materials, that is, to prepare a modified polyester fiber with dyeable properties. polyester. The polyester is a copolymer of polytrimethylene terephthalate (PTT) and PET, and the molar ratio of ethylene glycol to propylene glycol in its molecular structure ranges from 99:1 to 1:99. Although the copolyester has better dyeability, it is not easy to dye dark colors, and in order to improve its dyeability, the PTT content is higher, and the production cost is higher.

Contents of the invention

The technical problem to be solved by the present invention is to provide a modified copolyester material which is easy to dye dark colors, has uniform dyeing and high color fastness.

Another technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned copolyester with lower production cost.

The patent can effectively solve the above-mentioned problems by introducing a method of co-polymerizing a new diol component with EG, PTA and polyalkylene glycol.

The present invention is easy to dye dark color copolyester, is characterized in that containing the following material in weight percent therein:

Repeating unit of ethylene glycol terephthalate 35.0～90.0,

Repeating unit of propylene glycol terephthalate 5.0～50.0,

Average molecular weight is the polyalkylene glycol of 500～10000 The remaining amount.

The good dyeing performance of polytrimethylene terephthalate improves the dyeability of copolyester, and the addition of polyalkylene glycol further makes the structure of copolyester loose, and the dye uptake rate is greatly improved.

Preferably, the copolyester has an intrinsic viscosity of 0.35 to 1.00.

Preferably, it also contains the following substances with a weight percentage≤3: anti-ether agent and/or antioxidant and/or toner and/or heat stabilizer and/or co-catalyst.

Among them, the anti-ether agent is sodium acetate 100PPM, etc., the antioxidant 1010 is 200PPM, etc., the toner is cobalt acetate 100PPM, and the heat stabilizer is trimethyl phosphate 200PPM.

The preparation method of the present invention is characterized in that in the presence of titanium series and/or antimony series catalysts, two or more glycol monomer mixtures are carried out with terephthalic acid (TPA). Direct esterification, or transesterification with dimethyl terephthalate (DMT), the obtained esterified product is subjected to polycondensation reaction with polyalkylene glycol to obtain the product; wherein, the catalyst is Sb, Ti, Ge, Sn compound One or a mixture of several.

The preparation method of the above-mentioned easily dyeable dark copolyester has two process lines of direct esterification and transesterification, and each process step is:

1. Direct esterification route:

1) Mixing: In direct esterification, the molar ratios of terephthalic acid and diol monomers are: 1:1.05-2.0 with ethylene glycol, and 1:1.05-2.50 with 1,3-propanediol , while adding the catalyst;

2) Esterification: the temperature is 200-290°C, the pressure is 0.0-0.5Mpa, and it is carried out according to one of the following process steps: a) Terephthalic acid and ethylene glycol, 1,3-propanediol monomers are directly mixed with p- phthalic acid is carried out esterification; b) terephthalic acid is carried out direct esterification with ethylene glycol, 1,3-propanediol monomer respectively; c) bishydroxyethyl terephthalate monomer and terephthalic acid Formic acid and 1,3-propanediol monomer carry out direct esterification reaction; d) dipropylene glycol terephthalate monomer is carried out direct esterification reaction with terephthalic acid, ethylene glycol monomer;

3) Polycondensation: The obtained esterified product is added with a polycondensation catalyst, and the system is pre-condensed with polyalkylene glycol at 0.1-0.01Mpa and 220-270°C; the pressure is gradually reduced to ≤130pa, and the temperature is raised to 255-295°C to complete polycondensation products;

Among them, the catalyst is one or more of Sb, Ti, Ge, Sn compounds, such as antimony acetate, antimony oxide, antimony glycol, titanium oxalate, tetrabutyl titanate, germanium oxide, etc., which can be used as esterification catalyst or transesterification catalyst or polycondensation catalyst.

2. Ester exchange route:

1) Mixing: In the transesterification method, the molar ratio of dimethyl terephthalate to ethylene glycol is 1:1.10 to 2.0, and the molar ratio of dimethyl terephthalate to 1,3-propanediol is 1:1.05～2.50, add catalyst at the same time;

2) Transesterification: carried out at 200-240°C;

3) The polycondensation and catalyst are the same as the direct esterification route.

As preferably, a cocatalyst can be used in the polycondensation reaction, and the cocatalyst is one or a mixture of cobalt acetate, manganese acetate, magnesium acetate, calcium acetate, and sodium acetate.

Polyalkylene glycol can also be added before esterification or transesterification to facilitate operation.

The preparation method of the invention has reasonable design, is easy to realize industrialized production, and has low production cost; and the prepared copolyester has better dark color dyeing performance.

specific implementation plan

The present invention will be further described by specific examples below.

In an embodiment, the intrinsic viscosity of the obtained modified copolyester chips is tested with an Ubbelohde viscometer, and the solvent is a mixture of phenol and tetrachloroethane at 25° C., phenol: tetrachloroethane=1: 1 (weight ratio) .

Example 1, a of the direct esterification route—monomer mixed addition method

Mixing: 2.711mol terephthalic acid (PTA), 2.928mol ethylene glycol (EG) and 0.325mol 1,3-propanediol (PDO) are mixed together, then added to the reaction system, and the required amount of antimony acetate catalyst is added at the same time ; Carry out esterification at 220～240 ℃, pressure 0.3Mpa; Add 0.054mol polyalkylene glycol (molecular weight is 1000) and the required amount of tetrabutyl titanate catalyst after esterification reaction is finished, first in low After pre-condensation under vacuum for 1.5 hours, heat the temperature of the reaction system to 265°C and carry out polycondensation under a high vacuum of 50 Pa. After the polycondensation reaction is completed, stop stirring. The product is cast and pelletized to finally obtain a copolyester with an intrinsic viscosity of 0.55. slice.

Embodiment 2, b of the direct esterification route——BHET+BHPT method:

Mix 1.0mol of terephthalic acid (PTA), 1.3mol of ethylene glycol (EG) and the required amount of antimony trioxide catalyst and add them into the reaction system, and carry out esterification at 220-240°C and a pressure of 0.3Mpa. The esterification product bishydroxyethyl terephthalate (BHET) is obtained after the reaction is completed.

Mix 1.0mol terephthalic acid (PTA), 2.0mol 1,3-propanediol (PDO) and the required amount of tetraisopropyl titanate catalyst together and add to the reaction system at 220-240°C under a pressure of 0.3Mpa. Esterification, the esterification product dipropylene glycol terephthalate (BHPT) is obtained after the esterification reaction is completed.

Mix BHET, BHPT and 0.02mol polyalkylene glycol (molecular weight: 5000) and then add it to the reaction system. At the same time, add the required amount of tetraisopropyl titanate catalyst. After precondensation under low vacuum for 1.5 hours, Heat the temperature of the reaction system to 265°C and carry out polycondensation under a high vacuum of 50 Pa. After the polycondensation reaction is completed, the stirring is stopped, and the product is cast and pelletized to finally obtain copolyester chips with an intrinsic viscosity of 0.62.

Example 3, c of the direct esterification route——BHET (the esterification product of PTA and EG)+PTA+PDO method:

Mix 2.440mol terephthalic acid (PTA) and 4.145mol ethylene glycol (EG) together, then add them into the reaction system, and at the same time add the required amount of antimony acetate catalyst, and carry out esterification at 220-240°C and a pressure of 0.3Mpa. to obtain the esterified bishydroxyethyl terephthalate (BHET), and then add 0.27mol terephthalic acid, 0.539mol 1,3-propylene glycol (PDO), 0.067mol polyalkylene glycol after the esterification reaction (Molecular weight is 1000) and the required amount of tetrabutyl titanate catalyst, after pre-condensation under low vacuum for 1.5 hours, heat the temperature of the reaction system to 265°C and carry out polycondensation under 50Pa high vacuum, stop stirring after the polycondensation reaction is completed , the product is cast and pelletized to finally obtain copolyester chips with an intrinsic viscosity of 0.64.

Example 4, d of the direct esterification route——BHPT (PTA and 1,3-propanediol esterification product)+PTA+EG method:

Mix 1.440mol terephthalic acid (PTA) and 2.880mol 1,3-propanediol (PDO) together, then add them into the reaction system, and at the same time add the required amount of antimony acetate catalyst. Carry out esterification, obtain esterified product dipropylene glycol terephthalate (BHPT), add 1.27mol terephthalic acid (PTA), 1.778mol ethylene glycol (EG), 0.056mol polyalkylene Diol (molecular weight is 2500) and the required amount of tetrabutyl titanate catalyst, after pre-condensation under low vacuum for 1.5 hours, the temperature of the reaction system is heated to 265 ° C and polycondensation is carried out under 50Pa high vacuum, after the polycondensation reaction is completed Stirring was stopped, and the product was cast and pelletized to finally obtain copolyester chips with an intrinsic viscosity of 0.58.

Embodiment 5: one of transesterification route

After mixing 2.711mol dimethyl terephthalate, 2.928mol ethylene glycol and 0.325mol 1,3-propanediol (PDO), they were added to the reaction system, and the required amount of antimony acetate catalyst was added at the same time. Carry out transesterification reaction under normal pressure, add 0.067mol polyalkylene glycol (molecular weight is 1000) and the required amount of tetraisopropyl titanate catalyst again after transesterification reaction is finished, after precondensation under low vacuum 1.5 hours , heat the temperature of the reaction system to 265°C and carry out polycondensation under a high vacuum of 50 Pa. After the polycondensation reaction is completed, the stirring is stopped, and the product is cast and pelletized to finally obtain copolyester chips with an intrinsic viscosity of 0.56.

Embodiment 6～8: the two, three, four of transesterification route

Change monomer terephthalic acid (TPA) in embodiment 2～4 into monomer dimethyl terephthalate (DMT), pressurized esterification reaction is changed into normal pressure transesterification reaction, other reaction conditions are basically the same .

Comparative example 1:

After mixing 2.711mol of terephthalic acid and 2.625mol of ethylene glycol, add it to the reaction system, and at the same time add the required amount of antimony acetate catalyst, and carry out esterification at 220-240°C and a pressure of 0.3Mpa, and the esterification reaction is completed Then add 0.054mol polyalkylene glycol (molecular weight: 1000) and the required amount of tetrabutyl titanate catalyst, precondense under low vacuum for 1.5 hours, heat the temperature of the reaction system to 265 ° C and 50 Pa high The polycondensation is carried out under vacuum, and the stirring is stopped after the polycondensation reaction is completed, and the product is cast and pelletized to finally obtain copolyester chips with an intrinsic viscosity of 0.50.

Comparative example 2:

Mix 2.711mol of terephthalic acid, 2.928mol of ethylene glycol and 0.325mol of 1,3-propanediol together, then add to the reaction system, and at the same time add the required amount of antimony acetate catalyst, at 220～240℃, under the pressure of 0.3Mpa Carry out esterification, after the esterification reaction is completed, add the required amount of tetrabutyl titanate catalyst, pre-condense under low vacuum for 1.5 hours, heat the temperature of the reaction system to 265°C and carry out polycondensation under 50Pa high vacuum, polycondensation After the reaction is completed, the stirring is stopped, and the product is cast and pelletized to finally obtain copolyester chips with an intrinsic viscosity of 0.58.

After fully drying the copolymer slices prepared in the above examples and comparative examples, carry out a spinnability test on a small spinning machine to verify its spinnability. The apparent depth K/S values of fibers and fabrics were measured respectively, and it was found that the K/S values were about 30-50% higher than that of ordinary polyester. The specific results are shown in Table 1.

Table 1 Experimental test results Sample serial number Intrinsic viscosity [η]/dL/g Melting point Tm/℃ Spinnability K/S value Ethylene terephthalate repeating unit % Propylene glycol terephthalate repeating unit % Polyalkylene Glycol % Example 1 0.55 245～251 better 25.74 80 10.7 9.3 Example 2 0.64 252～260 good 30.82 38.5 41.4 20.1 Example 3 0.58 243～250 generally 24.08 79.3 9.4 11.3 Example 4 0.62 255～258 good 29.16 35.8 43.6 20.6 Example 5 0.56 247～254 better 28.50 80 10.7 9.3 Example 6 0.63 249～253 good 30.91 38.5 41.4 20.1 Example 7 0.45 238～246 Difference 25.87 79.3 9.4 11.3 Example 8 0.57 250～259 good 32.46 35.8 43.6 20.6 Comparative example 1 0.50 241～247 generally 19.72 - - - Comparative example 2 0.58 253～261 generally 23.54 - - -

The titanium-based and antimony-based catalysts in the present invention refer to one or more mixtures of Sb, Ti, Ge and Sn compounds disclosed before the application date. The anti-ether agent and/or antioxidant and/or toner and/or heat stabilizer and/or cocatalyst are all adjuvants disclosed before the filing date.

Claims (7)

1. An easy-to-dye dark copolyester, characterized in that it contains the following repeating units in weight percentage: Repeating unit of ethylene glycol terephthalate 35.0～90.0, Repeating unit of propylene glycol terephthalate 5.0～50.0, The remaining amount of polyalkylene glycol with an average molecular weight of 500-10,000. 2. The easy-to-dye dark copolyester according to claim 1, characterized in that its intrinsic viscosity is 0.35-1.00. 3. The easy-to-dye dark copolyester according to claim 1 or 2, characterized in that it also contains the following substances in a weight percentage ≤ 3.0: anti-ether agent and/or antioxidant and/or toner and/or thermal stabilizers and/or cocatalysts. 4. The preparation method of the easy-to-dye dark copolyester as claimed in claim 1, characterized in that, 1) Mixing: In direct esterification, the molar ratios of terephthalic acid and diol monomers are: 1:1.05-2.0 with ethylene glycol, and 1:1.05-2.50 with 1,3-propanediol , while adding the catalyst; In the transesterification method, the molar ratio of dimethyl terephthalate to ethylene glycol is 1:1.10~2.0, and the molar ratio of dimethyl terephthalate to 1,3-propanediol is 1:1.05~2.50 , while adding the catalyst; 2) Esterification: the temperature is 200-290°C, the pressure is 0.0-0.5Mpa, and it is carried out according to one of the following process steps: a) Terephthalic acid is directly esterified with ethylene glycol and 1,3-propanediol monomers Reaction; b) terephthalic acid carries out direct esterification reaction with ethylene glycol, 1,3-propanediol monomer respectively; c) bishydroxyethyl terephthalate monomer and terephthalic acid and 1,3- Propylene glycol monomer is carried out direct esterification reaction; d) dipropylene glycol terephthalate monomer is carried out direct esterification reaction with terephthalic acid and ethylene glycol monomer; Or transesterification: at 200-240°C; 3) Polycondensation: The obtained esterified product is added with a polycondensation catalyst, and the system is pre-condensed with polyalkylene glycol at 0.1-0.01Mpa and 220-270°C; the pressure is gradually reduced to ≤130pa, and the temperature is raised to 255-295°C to complete polycondensation products; Wherein, the catalyst is one or a mixture of Sb, Ti, Ge, Sn compounds, used as an esterification catalyst, a transesterification catalyst or a polycondensation catalyst. 5. The preparation method of the easy-to-dye dark-colored copolyester according to claim 4 is characterized in that in the polycondensation reaction, a cocatalyst is used, and the cocatalyst is cobalt acetate, manganese acetate, magnesium acetate, calcium acetate, and sodium acetate. One or a mixture of several. 6. The method for preparing the easy-to-dye dark-colored copolyester according to claim 4, wherein the polyalkylene glycol is added before esterification or transesterification. 7. The method for preparing the easy-to-dye dark-colored copolyester according to claim 5, wherein the polyalkylene glycol is added before esterification or transesterification.