Cationic dyeable flame retardant anti-dripping copolyester and method for preparing the same

Abstract

The present application relates to the technical field of copolyester, and discloses a cationic dyeable flame-retardant anti-dripping copolyester and a preparation method thereof, raw materials of the copolyester comprising terephthalic acid, ethylene glycol, isophthalic acid-5-sulfonate modified melamine salt, phosphorus-based reactive flame retardant and pentaerythritol; the addition amount of the isophthalic acid-5-sulfonate modified melamine salt accounting for 1-5% of the weight of the copolyester; the addition amount of the phosphorus-based reactive flame retardant accounting for 5000-7000 ppm of the weight of the copolyester; and the addition amount of the pentaerythritol accounting for 1-5% of the weight of the copolyester.In the present application, the phosphorus-based reactive flame retardant is used as a polyester intrinsic flame-retardant functional component, the isophthalic acid-5-sulfonate modified melamine salt and the pentaerythritol are used as added flame-retardant modified components, a synergistic flame-retardant mechanism is achieved, and the components directly participate in the polyester polymerization process, effectively solving the compatibility and dispersibility problems and not affecting subsequent processing performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copolyesters, and in particular to a cationic dyeable flame-retardant anti-dripping copolyester and a preparation method thereof. BACKGROUND

[0002] Polyethylene terephthalate (polyester, PET) is a semi-aromatic polymer obtained by polycondensation of terephthalic acid and ethylene glycol. It is applied to many fields such as synthetic fibers, packaging materials and engineering plastics due to its excellent comprehensive performance. PET fiber (i.e. "polyester") has become the largest and most widely used fiber variety in synthetic fibers due to its high modulus, high strength, high elasticity, shape retention and heat resistance, and currently accounts for more than 50% of the fiber market. However, due to the presence of aliphatic segments, PET is highly flammable, with a limiting oxygen index (LOI) of 21-22%, and generates a large amount of aliphatic free radicals, hydroxyl radicals and hydrogen radicals during combustion, which not only accelerates the decomposition of the material and the spread of the flame, but also releases toxic and harmful smoke, endangering escaping personnel. At the same time, the melt viscosity of PET is very low at high temperatures, and it is extremely easy to produce melt dripping during combustion, causing burns to personnel. With the widespread use of polyester products, its flammability, release of toxic and harmful smoke and tendency to melt and drip pose a serious fire threat to people's daily life. Once a fire occurs, it will most likely cause serious casualties and huge property losses. Therefore, it is urgent to modify polyester to be flame-retardant and anti-dripping.

[0003] With in-depth research on the flame-retardant modification of polyester, various flame retardants and flame-retardant methods have developed rapidly. Flame retardants for polyester can be divided into inorganic flame retardants and organic flame retardants. Inorganic flame retardants are convenient to use but have unsatisfactory flame-retardant effect and require a large amount of addition, which greatly affects the physical and mechanical properties of polyester. Organic flame retardants include halogen-based flame retardants, phosphorus-based flame retardants and nitrogen-based flame retardants. Halogen-based flame retardants have good flame-retardant effect but are not environmentally friendly; phosphorus-based flame retardants have good compatibility with polymers but have problems such as high energy consumption in copolymerization with polyester and poor resistance to separation in blending with polyester; nitrogen-based flame retardants are halogen-free and low-toxic but have low flame-retardant efficiency when used alone and need to be compounded with other flame retardants to achieve good flame-retardant effect. The flame-retardant effect of phosphorus-nitrogen synergistic flame retardants is better than that of single nitrogen-based flame retardants, but the problem of good dispersion of multiple components with polyester also needs to be solved. In addition, conventional flame retardants applied to polyester systems have a decrease in color fastness after fabric dyeing compared to unmodified polyester; at the same time, the flame-retardant performance of flame-retardant fabrics after dyeing is lower than that of un-dyed flame-retardant fabrics.

[0004] To solve this problem, the patent with publication number CN101864612A discloses a preparation method of cationic dyeable halogen-free flame-retardant polyester fiber, sodium sulfonate isophtalic acid and 2-carboxyethyl phenyl hypophosphite are added into a reaction container with deionized water, after the reaction, the reaction product is filtered out and dried to obtain a cationic dyeable flame-retardant compound; then the compound is reacted with terephthalic acid, ethylene glycol and a catalyst to obtain a cationic dyeable flame-retardant polyester chip. The deficiency of the method is that sodium sulfonate isophtalic acid and 2-carboxyethyl phenyl hypophosphite are only physically blended, and 2-carboxyethyl phenyl hypophosphite directly participates in the esterification of PET, which causes thermal degradation reaction and is not conducive to the later polymerization reaction of PET.

[0005] The patent with publication number CN114000226A discloses a preparation method of cationic dyeable flame-retardant high-strength polyester fiber, sodium sulfonate isophtalic acid and phosphorus intrinsic flame retardant are respectively esterified in ethylene glycol to obtain oligomers A and B, and then the oligomers A and B are subjected to polycondensation reaction with terephthalic acid glycol ester to obtain cationic dyeable flame-retardant polyester masterbatch. However, the method is the same as the above-mentioned patent, and only develops from the aspects of cationic dyeability and flame retardancy, and the functional components do not have synergistic enhancement effect of flame retardancy. SUMMARY

[0006] To solve the above technical problems, the present application provides a cationic dyeable flame-retardant anti-dripping copolyester and a preparation method thereof. Through the mutual cooperation and synergy of the functional components, good flame-retardant effect is achieved, and the PET polymerization process and subsequent processing performance are not affected, and a copolyester with excellent flame-retardant anti-dripping performance and good dyeing performance is obtained.

[0007] The object of the present application is achieved by the following technical solutions:

[0008] In a first aspect, the present application provides a cationic dyeable flame-retardant anti-dripping copolyester, the raw materials of the copolyester include terephthalic acid, ethylene glycol, isophthalic acid-5-sulfonate modified melamine salt, phosphorus reaction type flame retardant and pentaerythritol; the addition amount of the isophthalic acid-5-sulfonate modified melamine salt accounts for 1-5% of the weight of the copolyester; the addition amount of the phosphorus reaction type flame retardant is such that the phosphorus element accounts for 5000-7000 ppm of the weight of the copolyester; and the addition amount of the pentaerythritol accounts for 1-5% of the weight of the copolyester.

[0009] In the present application, the phosphorus reaction type flame retardant is used as the intrinsic flame-retardant functional component of the polyester, the isophthalic acid-5-sulfonate modified melamine salt and the pentaerythritol are used as the added flame-retardant modified components, the synergistic flame-retardant mechanism is achieved, and the components directly participate in the polyester polymerization process, effectively solving the compatibility and dispersion problems and not affecting the subsequent processing performance.

[0010] Specifically, the synergistic flame-retardant mechanism includes the following three aspects:

[0011] First, the phosphorus-based reactive flame retardant as the main flame-retardant component forms phosphoric acid as a dehydrating agent and promotes charring during combustion; phosphoric acid can absorb heat, preventing CO from being oxidized to CO2; a thin glassy or liquid protective layer is formed on the condensed phase surface. Therefore, the oxygen diffusion and heat and mass transfer between the gas phase and the solid phase are reduced, the carbon oxidation process is inhibited, and the thermal decomposition of the phosphorus-containing flame retardant is reduced, as follows: phosphorus-based flame retardant → metaphosphoric acid → phosphoric acid → polyphosphoric acid. Polyphosphoric acid is a stable compound that is not easily volatile and has strong dehydrating properties, forming a dense carbon layer to isolate the polymer surface from the air. At the same time, during polymer combustion, phosphorus compounds produce PO· free radicals, which can capture active H· or HO· in the flame region, reducing the concentration of H· or HO· in the flame, i.e., PO· + H· = HPO, so that the combustion chain reaction cannot continue.

[0012] Second, melamine salt, as a typical nitrogen-based flame retardant, on the one hand, generates N2, CO2, H2O, and other non-combustible gases during thermal decomposition, which dilutes the concentration of combustible gases and reduces the temperature of the material surface, inhibiting the chain reaction. On the other hand, melamine salt can cross-link with each other when heated, forming a carbon layer on the material surface, which can isolate heat, oxygen, and suppress smoke, thereby achieving anti-dripping effect. Isophthalic acid-5-sulfonate accelerates surface carbonization due to the aggregation of metal cations during combustion, and improves the gas-phase flame-retardant efficiency through covalent interaction with melamine salt, achieving a synergistic flame-retardant mechanism.

[0013] Third, pentaerythritol, as a typical high-carbon polyhydroxy compound, can be used as a charring agent for intumescent flame-retardant systems.

[0014] Therefore, by using intrinsic flame-retardant phosphorus-based flame retardants as acid sources, isophthalic acid-5-sulfonate modified melamine salt as gas sources, and pentaerythritol as carbon sources, an intumescent flame-retardant system is formed, which rapidly chars during combustion, and the modified components synergize with each other, achieving high-efficiency flame-retardant and anti-dripping effects.

[0015] In addition, isophthalic acid-5-sulfonate not only serves as a flame-retardant and anti-dripping modifier, but also as a typical modifier for cationic dyeable polyester, so that the flame-retardant and anti-dripping effect can be achieved while the dyeing performance of the polyester is significantly improved. The color fastness of the dyed fabric is not reduced compared to that of the unmodified flame-retardant fabric, and the flame-retardant performance of the dyed flame-retardant fabric is also not reduced compared to that of the undyed flame-retardant fabric.

[0016] Preferably, the preparation method of the isophthalic acid-5-sulfonate modified melamine salt comprises the following steps: dissolving isophthalic acid-5-sulfonate, acylation catalyst, condensing agent in an organic solvent, and stirring in an ice bath; then adding an acid-binding agent, and continuing to stir in an ice bath; then adding a melamine salt, and reacting at room temperature; then adding acetic acid, stirring under reflux, and then standing to obtain a solid precipitate; and then performing post-treatment to obtain the isophthalic acid-5-sulfonate modified melamine salt.

[0017] The cationic dyeable modifier isophthalic acid-5-sulfonate is chemically and covalently grafted with the melamine salt having a gas-phase flame-retardant mechanism through an amidation reaction. Compared with a traditional cationic dyeable polyester, the carboxyl groups of the isophthalic acid-5-sulfonate directly participate in the polyester polymerization process, and the cationic dyeable functional component of the present application does not affect the original regular molecular structure of PET, and thus does not affect the subsequent processing performance.

[0018] Preferably, the mass ratio of the isophthalic acid-5-sulfonate, the acylation catalyst, the condensing agent, the acid-binding agent, and the melamine salt is 1:2-3:2-3:2-3.5:2-3; the content of the isophthalic acid-5-sulfonate in the organic solvent is 20-40 mg / mL; and the amount of the acetic acid is the same as the amount of the organic solvent.

[0019] Preferably, the acylation catalyst is 1-hydroxybenzotriazole; the condensing agent is 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride; the acid-binding agent is triethylamine; and the organic solvent is N,N-dimethylformamide.

[0020] Preferably, the stirring time in the ice bath is 20-30 min; the continued stirring time in the ice bath is 30-60 min; the reaction time at room temperature is 12-14 h; and the stirring time under reflux is 10-12 h.

[0021] Preferably, the post-treatment is as follows: vacuum suction filtration of the solid precipitate obtained after the upper liquid is poured out, repeated cleaning with ethanol, vacuum suction filtration three times, air drying at 50-60℃ for 10-12 h, and then vacuum drying at 100-120℃ for 10-12 h.

[0022] Preferably, the isophthalic acid-5-sulfonate is sodium isophthalic acid-5-sulfonate and / or lithium isophthalic acid-5-sulfonate; and the melamine salt is melamine cyanurate and / or melamine polyphosphate.

[0023] Preferably, the phosphorus-based reactive flame retardant is 2-carboxyethyl phenyl phosphinic acid (CEPPA) and / or [(6-oxo-6H-dibenzo[C,E][1,2]oxaphosphorin-6-yl)methyl] butanedioic acid (DDP).

[0024] In a second aspect, the present application also provides a method for preparing the cationic dyeable flame-retardant anti-dripping copolyester, comprising the following steps:

[0025] (1) adding the isophthalic acid-5-sulfonate modified melamine salt and the pentaerythritol into the diol esterification liquid containing the phosphorus-based reactive flame retardant, stirring and then ultrasonic treating to obtain a functional modified liquid;

[0026] (2) mixing the terephthalic acid, the diol and the functional modified liquid, and then adding the catalyst to perform the esterification reaction;

[0027] (3) after the esterification is completed, performing the vacuum pre-shrinking reaction to discharge the excess diol;

[0028] (4) after the pre-shrinking is completed, performing the vacuum final-shrinking reaction to obtain the cationic dyeable flame-retardant anti-dripping copolyester.

[0029] In the present application, the functional components are mixed first to obtain the functional modified liquid, and then the functional modified liquid is added into the copolymerization to obtain the cationic dyeable flame-retardant anti-dripping copolyester. In this way, the melamine salt, the pentaerythritol and the phosphorus-based reactive flame retardant can form the hydrogen bond or the chemical bond action, and form the flame-retardant interconnection network, so that the mutual synergy among the functional components is better. Then, the functional components directly participate in the polyester polymerization process and are grafted onto the polyester molecular chain, and thus the original regular molecular structure of the PET is not affected, and thus the subsequent processing performance is not affected.

[0030] Preferably, in the diol esterification liquid of the phosphorus-based reactive flame retardant, the mass ratio of the phosphorus-based reactive flame retardant to the diol is 2-3:7-8; and the molar ratio of the alcohol to the acid after the mixing is 1:1.2-1.5.

[0031] Preferably, the temperature of the esterification reaction is 180-260℃, and the pressure is 0-0.35MPa; the temperature of the pre-shrinking reaction is 250-290℃, and the pressure is 0.2-2kPa; and the temperature of the final-shrinking reaction is 250-290℃, and the pressure is 50-300Pa.

[0032] Preferably, the catalyst is at least one of antimony trioxide, ethylene glycol antimony, antimony acetate, calcium acetate, zinc acetate, zinc oxide, sodium acetate, tetrabutyl titanate, tetraisopropyl titanate, tetraisooctyl titanate and organic amine compounds; and the addition amount of the catalyst is 100-3000ppm of the mass of the copolyester.

[0033] Preferably, the diol is at least one of ethylene glycol, propylene glycol, butanediol, pentanediol and 1,4-cyclohexane dimethanol.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] (1) Phosphorus-based reactive flame retardant as polyester intrinsic flame-retardant functional component, isophthalic acid-5-sulfonate modified melamine salt and pentaerythritol as additive flame-retardant modified component, to achieve synergistic enhancement of flame-retardant mechanism, and directly participate in polyester polymerization process, effectively solve the compatibility and dispersion problem, without affecting the subsequent processing performance;

[0036] (2) Cationic dyeable modifier isophthalic acid-5-sulfonate is chemically covalently grafted with melamine salt with gas phase flame-retardant mechanism through amidation reaction, the covalent action formed is helpful to improve the gas phase flame-retardant effect and accelerate the surface carbonization, and the cationic dyeable functional component will not affect the original regular molecular structure of PET and will not affect the flame-retardant performance after dyeing; (3) The polyester chip prepared by the application can obtain a sample by conventional injection molding technology, and the limiting oxygen index can reach 35%-40% without melt dripping phenomenon; the fabric obtained by conventional spinning and weaving technology has a limiting oxygen index of 33%-36%, the color fastness of the dyed fabric is ≥4 levels, the dye saturation value is >2.87, and the limiting oxygen index is 31%-34%. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 Structure diagram of isophthalic acid-5-sodium sulfonate modified melamine cyanurate (5-SSIPA-MC);

[0038] Figure 2 NMR spectrum of melamine cyanurate (MC) and 5-SSIPA-MC. DETAILED DESCRIPTION

[0039] The technical solutions of the application are illustrated by specific examples below, but the protection scope of the application is not limited thereto:

[0040] Example 1

[0041] 1. Preparation of cationic dyeable flame-retardant melt-drip-resistant copolyester

[0042] (1) Into a 1L three-necked flask, add 5-sulfonic acid sodium isophthalate 40g, acylation catalyst 1-hydroxybenzotriazole 45g, condensing agent 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride 63g, dissolved in 500ml of N,N-dimethylformamide, and stirred in ice bath for 30min; add acid binding agent triethylamine 42.5g, continue to stir in ice bath for 45min; add cyanuric acid melamine 84.2g, react at room temperature for 12h; transfer the mixed solution in the flask to a 2L three-necked flask, add 500ml of acetic acid, reflux and stir for 10h, stand for 6h, pour out the upper liquid to obtain solid precipitate; vacuum filtration, repeat with ethanol for cleaning, vacuum filtration three times; 50℃ air-drying for 12h, then transfer to 100℃ vacuum drying for 12h to obtain 5-sulfonic acid sodium isophthalate modified cyanuric acid melamine.

[0043] (2) Add 5-sulfonic acid sodium isophthalate modified cyanuric acid melamine (weight percentage in copolyester is 4%) and pentaerythritol (weight percentage in copolyester is 2%) to CEPPA-glycol esterification liquid (the mass ratio of CEPPA and glycol is 3:7), the amount of CEPPA added is 7000ppm of phosphorus content based on the weight of copolyester, stir uniformly, and ultrasonic treatment for 30min to obtain a functional modification liquid.

[0044] (3) After adding terephthalic acid, glycol and the functional modification liquid into the reaction kettle, the molar ratio of alcohol to acid is 1:1.25, and the catalyst (glycol antimony, antimony content 200ppm) is added, and esterification reaction is carried out, the esterification reaction temperature is 240℃, the pressure is 0.35MPa, and the reaction time is 150min.

[0045] (4) After esterification is completed, low vacuum pre-shrinking reaction is carried out, the reaction temperature is 270℃, the pressure is 1.5kPa, and the reaction time is 60min.

[0046] (5) After pre-shrinking is completed, high vacuum final shrinking reaction is carried out, the reaction temperature is 278℃, the pressure is 200Pa, and the reaction time is 150min; the melt product is obtained, then the melt is left to stand, discharged, and pelletized to obtain the cationic dyeable flame-retardant anti-dripping copolyester.

[0047] 2. Preparation of test strips and fabrics (a) The cationic dyeable flame-retardant anti-dripping copolyester is dried in a vacuum drum dryer, dried at 80℃ for 6h, then gradually heated to 125℃, and continue to dry for 18h; the dried pellets are prepared into test strips according to the conventional injection molding process, the injection molding temperature is 260℃, and the test strips are obtained.

[0048] (b) The dried slices in step (a) are spun according to a conventional spinning process, the spinning temperature is 277℃, the spinning speed is 3000m / min, the spinning specification is 75D / 48f, and cationic dyeable flame-retardant anti-dripping copolyester fibers are obtained; then the fabric is woven and dyed according to conventional weaving and dyeing processes, the dyeing process is as follows: cationic blue 2% (owf), bath ratio 1:25, glacial acetic acid 2.5ml / L, temperature 125℃, dyeing for 40min; the soaping process is as follows: soap chips 5g / L, sodium carbonate 2g / L, bath ratio 1:50, temperature 60℃, soaping for 30min; and the fabric is obtained.

[0049] Example 2

[0050] 1. Preparation of cationic dyeable flame-retardant anti-dripping copolyester

[0051] (1) A 1L three-necked flask is added with 40g of sodium 5-sulfonate isophthalic acid, 50.7g of acylation catalyst 1-hydroxybenzotriazole, 71.2g of condensing agent 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, which are dissolved in 500ml of N,N-dimethylformamide and stirred in an ice bath for 30min; 42.5g of acid-binding agent triethylamine is added, and stirring in an ice bath is continued for 60min; 115g of melamine cyanurate is added, and reaction is carried out at room temperature for 12h; the mixed solution in the flask is transferred to a 2L three-necked flask, 500ml of acetic acid is added, reflux stirring is carried out for 10h, and standing is carried out for 6h; the upper liquid is poured out, and solid precipitate is obtained; vacuum filtration is carried out, and washing with ethanol is repeated three times; air-drying is carried out at 50℃ for 12h, and then vacuum drying is carried out at 100℃ for 12h, and sodium 5-sulfonate isophthalic acid modified melamine cyanurate is obtained.

[0052] (2) Sodium 5-sulfonate isophthalic acid modified melamine cyanurate (accounting for 2% of the weight of the copolyester) and pentaerythritol (accounting for 1% of the weight of the copolyester) are added to DDP-glycol esterification liquid (the mass ratio of DDP and glycol is 3:7), the amount of DDP added is such that the phosphorus content accounts for 6500ppm of the weight of the copolyester, stirring is uniform, and ultrasonic treatment is carried out for 30min, and a functional modification liquid is obtained.

[0053] (3) Terephthalic acid, glycol and the functional modification liquid are added to a reaction kettle, the molar ratio of alcohol to acid is 1:1.25, a catalyst (antimony acetate, the antimony content is 200ppm) is added, esterification reaction is carried out, the esterification reaction temperature is 240℃, the pressure is 0.35MPa, and reaction is carried out for 150min.

[0054] (4) After esterification is completed, low vacuum pre-shrinking reaction is carried out, the reaction temperature is 270℃, the pressure is 1.5kPa, and reaction is carried out for 60min;

[0055] (5) After the pre-shrinking is finished, high-vacuum final-shrinking reaction is entered, the reaction temperature is 278℃, the pressure is 200Pa, and the reaction is performed for 150min; a product melt is obtained, then the melt is left to stand, discharged, and pelletized to obtain the cationic dyeable flame-retardant anti-dripping polyester.

[0056] 2. Preparation of the test sample and fabric (a) The cationic dyeable flame-retardant anti-dripping copolyester is dried in a vacuum drum dryer, dried at 80℃ for 6h, gradually heated to 125℃, and dried for another 18h; the dried chips are subjected to sample preparation according to a conventional injection molding process, the injection molding temperature is 260℃, and the sample is obtained.

[0057] (b) The dried chips in step (a) are subjected to spinning according to a conventional spinning process, the spinning temperature is 277℃, the spinning speed is 3000m / min, the spinning specification is 75D / 48f, and the cationic dyeable flame-retardant anti-dripping copolyester fiber is obtained; then the fabric is woven and dyed according to a conventional weaving process and dyeing process, the dyeing process is as follows: cationic blue 2% (owf), bath ratio 1:25, glacial acetic acid 2.5ml / L, temperature 125℃, and dyeing time 40min; the soaping process is as follows: soap chips 5g / L, sodium carbonate 2g / L, bath ratio 1:50, temperature 60℃, and soaping time 30min; and the fabric is obtained.

[0058] Example 3

[0059] 1. Preparation of the cationic dyeable flame-retardant anti-dripping copolyester

[0060] (1) A 1L three-necked flask is added with 38g of sodium 5-sulfonate isophthalic acid, 50.7g of acylation catalyst 1-hydroxybenzotriazole, and 71.2g of condensing agent 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride, which are dissolved in 500ml of N,N-dimethylformamide and stirred in an ice bath for 30min; 45g of acid-binding agent triethylamine is added, and stirring is continued in an ice bath for 45min; 34g of cyanuric acid melamine is added, and reaction is performed at room temperature for 12h; the mixed solution in the flask is transferred to a 2L three-necked flask, 500ml of acetic acid is added, reflux stirring is performed for 10h, left to stand for 6h, and the upper liquid is poured out to obtain a solid precipitate; vacuum filtration is performed, and the precipitate is repeatedly washed with ethanol and vacuum filtered three times; air-drying is performed at 50℃ for 12h, and then vacuum drying is performed at 100℃ for 12h to obtain sodium 5-sulfonate isophthalic acid modified cyanuric acid melamine.

[0061] (2) Sodium 5-sulfonate isophthalic acid modified cyanuric acid melamine (accounting for 3% of the weight of the copolyester) and pentaerythritol (accounting for 1% of the weight of the copolyester) are added to a CEPPA-glycol esterification liquid (the mass ratio of CEPPA and glycol is 2.5:7.5), and the amount of CEPPA added is such that the phosphorus content accounts for 7000ppm of the weight of the copolyester; stirring is performed, and ultrasonic treatment is performed for 30min to obtain a functional modification liquid.

[0062] (3) Into the reactor, terephthalic acid, ethylene glycol, and functional modification liquid were added and mixed, the molar ratio of alcohol to acid was 1:1.15, a catalyst (tetrabutyl titanate, titanium content 10 ppm) was added, esterification was carried out, the esterification temperature was 235°C, the pressure was 0.3 MPa, and the reaction time was 150 min.

[0063] (4) After the esterification was completed, low-vacuum pre-shrinking was carried out, the reaction temperature was 270°C, the pressure was 1.5 kPa, and the reaction time was 60 min.

[0064] (5) After the pre-shrinking was completed, high-vacuum final shrinking was carried out, the reaction temperature was 275°C, the pressure was 200 Pa, and the reaction time was 150 min; a melt was obtained, and then the melt was left to stand, discharged, and pelletized to obtain a cationic dyeable flame-retardant anti-dripping copolyester.

[0065] 2. Preparation of test bars and fabrics (a) The cationic dyeable flame-retardant anti-dripping copolyester was dried in a vacuum drum dryer, dried at 70°C for 6 h, gradually heated to 120°C, and dried for another 18 h; the dried chips were used to prepare test bars according to a conventional injection molding process, the injection molding temperature was 260°C, and the test bars were obtained.

[0066] (b) The dried chips in step (a) were used to spin according to a conventional spinning process, the spinning temperature was 277°C, the spinning speed was 3000 m / min, the spinning specification was 75D / 48f, and cationic dyeable flame-retardant anti-dripping copolyester fibers were obtained; then the fibers were used to weave and dye fabrics according to conventional weaving and dyeing processes, the dyeing process was as follows: cationic blue 2% (owf), bath ratio 1:25, glacial acetic acid 2.5 ml / L, temperature 125°C, and dyeing time 40 min; the soaping process was as follows: soap chips 5 g / L, sodium carbonate 2 g / L, bath ratio 1:50, temperature 60°C, and soaping time 30 min; and the fabrics were obtained.

[0067] Example 4

[0068] 1. Preparation of cationic dyeable flame-retardant anti-dripping copolyester

[0069] (1) Into a 1L three-necked flask, add 5-sulfonic acid sodium isophthalate 40g, acylation catalyst 1-hydroxybenzotriazole 50g, condensing agent 1-ethyl-3-(3- dimethylaminopropyl)carbodiimide hydrochloride 72g, dissolved in 500ml of N,N- dimethylformamide, and ice-bath stirring for 30min; add acid-binding agent triethylamine 42.5g, continue ice-bath stirring for 50min; add cyanuric acid melamine 84.2g, react at room temperature for 12h; transfer the mixed solution in the flask to a 2L three-necked flask, add 500ml of acetic acid, reflux stirring for 10h, stand for 6h, pour out the upper liquid, to obtain solid precipitate; vacuum filtration, repeat with ethanol for cleaning, vacuum filtration three times; 50℃ air-drying for 12h, then transfer to 100℃ vacuum drying for 12h, to obtain 5-sulfonic acid sodium isophthalate modified cyanuric acid melamine.

[0070] (2) Add 5-sulfonic acid sodium isophthalate modified cyanuric acid melamine (2% by weight in the copolyester) and pentaerythritol (2% by weight in the copolyester) to the CEPPA-ethylene glycol esterification liquid (the mass ratio of CEPPA to ethylene glycol is 3:7, the amount of CEPPA added is to make the phosphorus content account for 7000ppm of the weight of the copolyester, stir uniformly, ultrasonic treatment for 30min, to obtain a functional modification liquid.

[0071] (3) After adding terephthalic acid, ethylene glycol and the functional modification liquid to the reaction kettle, the molar ratio of alcohol to acid is 1:1.25, add catalyst (antimony trioxide, antimony content 220ppm), carry out esterification reaction, esterification reaction temperature 240℃, pressure 0.35MPa, reaction time 150min.

[0072] (4) After esterification is completed, carry out low vacuum pre-shrinking reaction, reaction temperature 270℃, pressure 1.5kPa, reaction time 60min;

[0073] (5) After pre-shrinking is completed, enter high vacuum final shrinking reaction, reaction temperature 278℃, pressure 200Pa, reaction time 150min; obtain the product melt, then let the melt stand, discharge, and pelletize, to obtain the cationic dyeable flame-retardant anti-dripping polyester.

[0074] 2. Preparation of test bars and fabrics (a) Dry the cationic dyeable flame-retardant anti-dripping copolyester in a vacuum drum dryer, dry at 80℃ for 6h, then gradually heat to 125℃, continue to dry for 18h; after drying, the chips are prepared into test bars according to the conventional injection molding process, injection molding temperature 260℃, to obtain the test bars.

[0075] (b) The dried chips in step (a) are spun according to the conventional spinning process, the spinning temperature is 277°C, the spinning speed is 3000 m / min, and the spinning specification is 75D / 48f, to obtain the cationic dyeable flame-retardant anti-dripping copolyester fiber; then the fabric is woven and dyed according to the conventional weaving process and dyeing process, the dyeing process is as follows: cationic blue 2% (owf), bath ratio 1:25, glacial acetic acid 2.5 ml / L, temperature 125°C, dyeing for 40 min; the soaping process is as follows: soap chips 5 g / L, sodium carbonate 2 g / L, bath ratio 1:50, temperature 60°C, soaping for 30 min; to obtain the fabric.

[0076] Comparative Example 1

[0077] The difference from Example 1 is that the pure PET resin is prepared without adding any cationic flame-retardant anti-dripping component.

[0078] 1. Polyester (PET resin)

[0079] 2. Preparation of test bars and fabric (a) The PET resin is dried in a vacuum drum dryer, dried at 80°C for 6 h, and then gradually heated to 125°C, and dried for another 18 h; the dried chips are prepared into bars according to the conventional injection molding process, the injection molding temperature is 260°C, to obtain the bars.

[0080] (b) The dried chips in step (a) are spun according to the conventional spinning process, the spinning temperature is 277°C, the spinning speed is 3000 m / min, and the spinning specification is 75D / 48f, to obtain the cationic dyeable flame-retardant anti-dripping copolyester fiber; then the fabric is woven and dyed according to the conventional weaving process and dyeing process, the dyeing process is as follows: cationic blue 2% (owf), bath ratio 1:25, glacial acetic acid 2.5 ml / L, temperature 125°C, dyeing for 40 min; the soaping process is as follows: soap chips 5 g / L, sodium carbonate 2 g / L, bath ratio 1:50, temperature 60°C, soaping for 30 min; to obtain the fabric.

[0081] Comparative Example 2

[0082] The difference from Example 1 is that in the preparation of the cationic dyeable flame-retardant anti-dripping copolyester, the sodium 5-sulfonate isophthalate and cyanuric acid melamine are directly added according to the mass ratio of 1:1.

[0083] 1. Preparation of cationic dyeable flame-retardant anti-dripping copolyester

[0084] (1) adding sodium isophthalate-5-sulfonate-cyanuric acid melamine (2% by weight in the copolyester, sodium isophthalate-5-sulfonate and cyanuric acid melamine are mixed in a mass ratio of 1:1) and pentaerythritol (2% by weight in the copolyester) into a CEPPA-glycol esterification liquid (the mass ratio of CEPPA to glycol is 3:7), the amount of CEPPA added is to make the phosphorus content account for 7000 ppm of the weight of the copolyester, stirring uniformly, ultrasonic treatment for 30 min, to obtain a functional modification liquid.

[0085] (2) adding terephthalic acid, glycol and the functional modification liquid into a reaction kettle, the molar ratio of alcohol to acid is 1:1.25, adding a catalyst (glycol antimony, the antimony content is 200 ppm), performing esterification reaction, the esterification reaction temperature is 240°C, the pressure is 0.35 MPa, and the reaction time is 150 min.

[0086] (3) after the esterification is completed, performing low-vacuum pre-shrinking reaction, the reaction temperature is 270°C, the pressure is 1.5 kPa, and the reaction time is 60 min;

[0087] (4) after the pre-shrinking is completed, performing high-vacuum final shrinking reaction, the reaction temperature is 278°C, the pressure is 200 Pa, and the reaction time is 150 min; obtaining a melt product, then placing the melt, discharging, and cutting into granules, to obtain the cationic dyeable flame-retardant anti-dripping copolyester.

[0088] Comparative Example 3

[0089] The difference from Example 1 is that no sodium isophthalate-5-sulfonate modified cyanuric acid melamine is added in the preparation of the cationic dyeable flame-retardant anti-dripping copolyester.

[0090] 1. Preparation of the cationic dyeable flame-retardant anti-dripping copolyester

[0091] (1) adding pentaerythritol (2% by weight in the copolyester) into a CEPPA-glycol esterification liquid (the mass ratio of CEPPA to glycol is 3:7), the amount of CEPPA added is to make the phosphorus content account for 7000 ppm of the weight of the copolyester, stirring uniformly, ultrasonic treatment for 30 min, to obtain a functional modification liquid.

[0092] (2) adding terephthalic acid, glycol and the functional modification liquid into a reaction kettle, the molar ratio of alcohol to acid is 1:1.25, adding a catalyst (glycol antimony, the antimony content is 200 ppm), performing esterification reaction, the esterification reaction temperature is 240°C, the pressure is 0.35 MPa, and the reaction time is 150 min.

[0093] (3) after the esterification is completed, performing low-vacuum pre-shrinking reaction, the reaction temperature is 270°C, the pressure is 1.5 kPa, and the reaction time is 60 min;

[0094] (4) After the pre-shrinkage is completed, high vacuum final shrinkage reaction is entered, the reaction temperature is 278℃, the pressure is 200Pa, and the reaction is performed for 150min; a product melt is obtained, and then the melt is placed, discharged, and cut into particles to obtain the cationic dyeable flame-retardant anti-dripping copolyester.

[0095] Comparative Example 4

[0096] The difference from Example 1 is that no CEPPA intrinsic flame retardant is added in the preparation of the cationic dyeable flame-retardant anti-dripping copolyester.

[0097] 1. Preparation of the cationic dyeable flame-retardant anti-dripping copolyester

[0098] (1) A 1L three-necked flask is added with 40g of sodium 5-sulfonate isophthalic acid, 45g of acylation catalyst 1-hydroxybenzotriazole, 63g of condensing agent 1-ethyl-3-(3-dimethylaminopropyl) carbonyldiimidazole hydrochloride, which is dissolved in 500ml of N,N-dimethylformamide and stirred in an ice bath for 30min; 42.5g of acid-binding agent triethylamine is added, and stirring in an ice bath is continued for 45min; 84.2g of cyanuric acid melamine is added, and reaction is performed at room temperature for 12h; the mixed solution in the flask is transferred to a 2L three-necked flask, 500ml of acetic acid is added, reflux stirring is performed for 10h, and the solution is left to stand for 6h, and the upper liquid is poured out to obtain a solid precipitate; vacuum filtration is performed, and the washing with ethanol is repeated three times; air-drying is performed at 50℃ for 12h, and then vacuum drying is performed at 100℃ for 12h to obtain sodium 5-sulfonate isophthalic acid modified cyanuric acid melamine.

[0099] (2) The sodium 5-sulfonate isophthalic acid modified cyanuric acid melamine (accounting for 4% by weight in the copolyester) and pentaerythritol (accounting for 2% by weight in the copolyester) are added to a glycol solution, stirred uniformly, and ultrasonically treated for 30min to obtain a functional modification liquid.

[0100] (3) The terephthalic acid, glycol, and functional modification liquid are added to a reaction kettle and mixed, the alcohol-acid molar ratio is 1:1.25, a catalyst (glycol antimony, with an antimony content of 200ppm) is added, and esterification reaction is performed, the esterification reaction temperature is 240℃, the pressure is 0.35MPa, and the reaction is performed for 150min.

[0101] (4) After the esterification is completed, low vacuum pre-shrinkage reaction is performed, the reaction temperature is 270℃, the pressure is 1.5kPa, and the reaction is performed for 60min.

[0102] (5) After the pre-shrinkage is completed, high vacuum final shrinkage reaction is entered, the reaction temperature is 278℃, the pressure is 200Pa, and the reaction is performed for 150min; a product melt is obtained, and then the melt is placed, discharged, and cut into particles to obtain the cationic dyeable flame-retardant anti-dripping copolyester.

[0103] Comparative Example 5

[0104] The difference from Example 1 is that no pentaerythritol is added in the preparation of the cationic dyeable flame-retardant anti-dripping copolyester.

[0105] 1. Preparation of cationic dyeable flame-retardant anti-dripping copolyester

[0106] (1) A 1L three-necked flask was added with 40g of sodium 5-sulfonate isophthalic acid, 45g of acylation catalyst 1-hydroxybenzotriazole, 63g of condensing agent 1-ethyl-3-(3-dimethylaminopropyl) carbonyldiimidazole hydrochloride, which were dissolved in 500ml of N,N-dimethylformamide and stirred in ice bath for 30min; 42.5g of acid-binding agent triethylamine was added, and the stirring was continued in ice bath for 45min; 84.2g of melamine cyanurate was added, and the reaction was carried out at room temperature for 12h; the mixed solution in the flask was transferred to a 2L three-necked flask, 500ml of acetic acid was added, and the stirring was carried out under reflux for 10h, and the solution was left to stand for 6h, and the upper liquid was poured out to obtain a solid precipitate; vacuum filtration was carried out, and the washing with ethanol was repeated for three times; air-drying was carried out at 50℃ for 12h, and then vacuum drying was carried out at 100℃ for 12h to obtain sodium 5-sulfonate isophthalic acid modified melamine cyanurate.

[0107] (2) The sodium 5-sulfonate isophthalic acid modified melamine cyanurate (3% by weight in the copolyester) was added to the CEPPA-glycol esterification liquid (the mass ratio of CEPPA and glycol was 3:7), and the amount of CEPPA added was to make the phosphorus content account for 7000ppm of the weight of the copolyester, and the stirring was uniform, and the ultrasonic treatment was carried out for 30min to obtain a functionally modified liquid.

[0108] (3) The terephthalic acid, glycol and the functionally modified liquid were mixed in the reaction kettle, and the molar ratio of alcohol to acid was 1:1.25, and the catalyst (glycol antimony, the content of antimony was 200ppm) was added, and the esterification reaction was carried out, and the esterification reaction temperature was 240℃, and the pressure was 0.35MPa.

[0109] (4) After the esterification was completed, the low vacuum pre-shrinking reaction was carried out, and the reaction temperature was 270℃, and the pressure was 1.5kPa.

[0110] (5) After the pre-shrinking was completed, the high vacuum final shrinking reaction was carried out, and the reaction temperature was 278℃, and the pressure was 200Pa; the product melt was obtained, and then the melt was left to stand, discharged and pelletized to obtain the cationic dyeable flame-retardant anti-dripping copolyester.

[0111] The weaving process and dyeing process for fabric preparation in the above examples and comparative examples are the same, and the cationic dyeable flame-retardant anti-dripping copolyester, swatches and fabrics prepared from the examples and comparative examples are subjected to performance testing according to GB / T 14189-2008, GB / T 2408-2008, GB / T 5454-1997, FZ / T 50021, GB / T 3921-2008 and FZ / T 50019-2013, and the results are shown in Table 1.

[0112] Table 1

[0113]

[0114]

[0115] As shown in Table 1, the cationic dyeable flame-retardant anti-dripping polyester prepared by the application has good polymerization effect, and the addition of the isophthalic acid-5-sulfonate modified melamine salt effectively reduces the content of terminal carboxyl groups and diethylene glycol in the system, which is beneficial to improving the polymerization effect. Figure 1 As shown in Table 1, the isophthalic acid-5-sulfonate modified melamine cyanurate (5-SSIPA-MC) has good covalent bond effect with MC. Figure 2 As shown in Table 1, the isophthalic acid-5-sulfonate modified melamine cyanurate (5-SSIPA-MC) has good covalent bond effect with MC.

[0116] As shown in Table 1, the isophthalic acid-5-sulfonate modified melamine cyanurate (5-SSIPA-MC) has good covalent bond effect with MC.

[0117] The above is only a preferred embodiment of the application, and does not limit the patent scope of the application, and any equivalent structure or equivalent process transformation in the specification of the application, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the application.

Claims

1. A process for the preparation of a cationic dyeable flame retardant drip resistant copolyester characterized in that, It comprises the following steps: (1) Dissolve isophthalic acid-5-sulfonate, 1-hydroxybenzotriazole, 1-ethyl-3-(3-dimethylaminopropyl) carbonyl diimide hydrochloride in an organic solvent, and stir in an ice bath; add triethylamine, and continue to stir in an ice bath; add melamine salt, and react at room temperature; the mass ratio of isophthalic acid-5-sulfonate, 1-hydroxybenzotriazole, 1-ethyl-3-(3-dimethylaminopropyl) carbonyl diimide hydrochloride, triethylamine and melamine salt is 1:2-3:2-3:2-3.5:2-3; add acetic acid, stir under reflux, and then stand still; the precipitate is obtained by post-treatment to obtain isophthalic acid-5-sulfonate modified melamine salt; Add isophthalic acid-5-sulfonate modified melamine salt and pentaerythritol into a dihydric alcohol esterification solution containing a phosphorus-based reactive flame retardant, stir, and then ultrasonic to obtain a functional modified solution; the addition amount of isophthalic acid-5-sulfonate modified melamine salt and pentaerythritol accounts for 1-5% and 1-5% of the weight of the copolyester respectively; the phosphorus-based reactive flame retardant is CEPPA and / or DDP, and the addition amount is such that the phosphorus element accounts for 5000-7000 ppm of the weight of the copolyester; (2) Mix terephthalic acid, dihydric alcohol and the functional modified solution, and add a catalyst for esterification reaction; (3) After the esterification is completed, perform vacuum pre-shrinkage reaction to discharge excess dihydric alcohol; (4) After the pre-shrinkage is completed, perform vacuum final shrinkage reaction.

2. The process for the preparation of cationic dyeable flame retardant drip resistant copolyester as claimed in claim 1, wherein, The content of the isophthalic acid-5-sulfonate in the organic solvent is 20-40 mg / mL.

3. The preparation method of the cationic dyeable flame-retardant and anti-dripping copolyester as described in claim 1 or 2, characterized in that, The organic solvent is N,N-dimethylformamide.

4. The method for preparing the cationic dyeable flame-retardant and anti-dripping copolyester as described in claim 1 or 2, characterized in that, The stirring time in the ice bath is 20-30 min; the continued stirring time in the ice bath is 30-60 min; the reaction time at room temperature is 12-14 h; and the stirring time under reflux is 10-12 h.

5. The method for preparing the cationic dyeable flame-retardant and anti-dripping copolyester as described in claim 1 or 2, characterized in that, The isophthalic acid-5-sulfonate is sodium isophthalic acid-5-sulfonate and / or lithium isophthalic acid-5-sulfonate; and the melamine salt is melamine cyanurate and / or melamine polyphosphate.

6. The process for preparing cationic dyeable flame retardant drip resistant copolyester as claimed in claim 1, wherein, In the dihydric alcohol esterification solution containing the phosphorus-based reactive flame retardant, the mass ratio of the phosphorus-based reactive flame retardant and dihydric alcohol is 2-3:7-8; and the molar ratio of the mixed alcohol and acid is 1:1.2-1.

5.

7. The process for the preparation of cationic dyeable flame retardant drip resistant copolyester as claimed in claim 6, wherein, The esterification reaction is performed at a temperature of 180-260 ℃ and a pressure of 0-0.35 MPa; the pre-shrinkage reaction is performed at a temperature of 250-290 ℃ and a pressure of 0.2-2 kPa; and the final shrinkage reaction is performed at a temperature of 250-290 ℃ and a pressure of 50-300 Pa.

8. The process for preparing cationic dyeable flame retardant drip resistant copolyester as claimed in claim 1, wherein, The catalyst is at least one of antimony trioxide, ethylene glycol antimony, antimony acetate, calcium acetate, zinc acetate, zinc oxide, sodium acetate, tetrabutyl titanate, tetraisopropyl titanate, tetraisooctyl titanate and organic amine compounds.

9. The process for preparing cationic dyeable flame retardant drip resistant copolyester of claim 1, wherein, The dihydric alcohol is at least one of ethylene glycol, propylene glycol, butanediol, pentanediol and 1,4-cyclohexanedimethanol.

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