Long-lasting flame-retardant polyester monofilament and preparation method thereof

Abstract

The present invention relates to a long-lasting flame-retardant polyester monofilament and a preparation method thereof. First, a furan structure-modified polyester and a water-soluble polyester are melt-blended and extruded to obtain a modified polyester precursor, and then the modified polyester precursor is placed in a flame retardant solution at 60 to 90°C for treatment, so that the water-soluble polyester component in the modified polyester precursor is dissolved in the flame retardant solution, and then the treated modified polyester precursor is placed in a flame retardant solution at a temperature of 60 to 98°C for the first stretching, and finally the modified polyester precursor after the first stretching is post-treated to obtain a long-lasting flame-retardant polyester monofilament; the obtained product consists of a polyester monofilament and a flame retardant layer distributed on the surface of the polyester monofilament. The preparation method of the present invention reduces the amount of flame retardant used and has a simple process flow; the product of the present invention is resistant to water washing during use, the flame retardant will not be lost due to outward migration or breakage due to connection with the main chain, and the flame retardant performance retention rate reaches more than 95%.

Description

Technical Field

[0001] The invention belongs to the technical field of flame retardancy and relates to a long-acting flame retardant polyester monofilament and a preparation method thereof. Background Art

[0002] Polyester fiber is the largest and most widely used type of synthetic fiber. It has good chemical resistance, friction resistance and excellent mechanical properties. As the application range of polyester fiber gradually expands, some special application environments have put forward requirements for the flame retardant properties of polyester fiber. Flame retardant polyester monofilament is an important type of polyester monofilament. It is used for the preparation of raw materials for webbing, clothing accessories, mattresses, handicrafts, papermaking nets, etc., and has broad application prospects.

[0003] In the research of flame retardant polyester monofilament, many researchers and institutions have carried out relevant research.

[0004] Chinese patent CN104328529B relates to a flame-retardant polyester monofilament and a production method thereof, wherein the flame-retardant PBT slices are added to the bright polyester slices at a mass fraction of 10 to 20%; the flame-retardant PBT slices and the bright polyester slices are melt-spun to obtain the flame-retardant polyester monofilament; wherein, nano-quantum energy ore powder is mixed with tea charcoal, coarsely ground and then calcined to obtain a coarsely ground composite powder, which is then secondary ground with nano-magnesium hydroxide, and then oxidized and acidified to obtain an acidified flame-retardant nano-composite powder, and PBT flame-retardant slices are prepared by in-situ polymerization of the composite functional powder, but the method does not mention the specific flame-retardant performance indicators of the flame-retardant polyester monofilament, the overall preparation process is relatively complicated, and excessive addition of flame-retardant functional powder affects the processing and use performance of the monofilament.

[0005] Chinese patent CN109797541A relates to PET flame-retardant monofilaments, which include a PET core bundle and a flame-retardant layer coated on the outside of the PET core bundle. The outer flame-retardant layer contains modified components such as ultraviolet curing resin, polyvinyl chloride resin, polyurethane resin, wood powder, porous layered silicate flame retardant, etc., to achieve the flame retardant effect of the polyester monofilament. However, the added flame retardant needs to overcome the problems of dispersion and migration of the flame retardant in the matrix during processing and application. At the same time, the processing conditions in the preparation of the skin-core structure are required to be relatively high. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a long-lasting flame-retardant polyester monofilament and a preparation method thereof;

[0007] To achieve the above object, the scheme adopted by the present invention is as follows:

[0008] A method for preparing a long-lasting flame-retardant polyester monofilament comprises the following steps: firstly, melt-blending and extruding a furan structure-modified polyester with a water-soluble polyester to obtain a modified polyester precursor, then treating the modified polyester precursor in a flame retardant solution at 60 to 90° C. to dissolve the water-soluble polyester component in the modified polyester precursor in the flame retardant solution, then treating the modified polyester precursor in a flame retardant solution at 60 to 98° C. to perform a first stretching, and finally post-treating the modified polyester precursor after the first stretching to obtain a long-lasting flame-retardant polyester monofilament;

[0009] After the polyester melt is extruded, in order to cool and shape the melt after extrusion, it is usually selected to be carried out in an aqueous solution environment with a large specific heat capacity. The present invention optimizes the aqueous solution into a flame retardant solution during the melt cooling process, and the cooling temperature is 60 to 90°C. At this temperature, the melt can be shaped after extrusion. At the same time, the temperature of the flame retardant solution in the cooling process stage is lower than the glass transition temperature of the modified polyester. Different cooling temperatures are set according to the cooling requirements of the modified polyester with different contents of furan structure. At the same time, the temperature setting within this range also ensures the dissolution requirements of water-soluble polyester with different contents. If the temperature is too low, the solubility of the water-soluble polyester is reduced, and the "cavity structure" cannot be effectively formed. The formation of the cavity structure can improve the flexibility of the modified polyester monofilament, bring sweat-conducting and warm-keeping functions, increase the surface area of ​​the flame-retardant modified polyester monofilament, and further enable more flame retardants to be connected to the surface layer of the monofilament;

[0010] During the first stretching process of the monofilament, the temperature of the environment in which the monofilament is located must be above its glass transition temperature. Due to the different furandicarboxylic acid structure contents in the modified polyester precursor, the corresponding glass transition temperatures of the materials are also different. Therefore, the temperature range selected during the first stretching process is 60-98°C. At the same time, since an aqueous solution containing a flame retardant is selected during the first stretching process, the maximum temperature of the solution is selected to be 98°C, which can not only meet the processing requirements, but also reduce the equipment requirements and energy consumption required during the drawing process.

[0011] The method of the present invention can adopt a discontinuous production process or a continuous production process;

[0012] When continuously produced, the content of the water-soluble polyester dissolved in the solution in the cooling solution at a temperature of 60 to 90°C will gradually increase as the processing proceeds, and will enter the cavity together with the flame retardant, but due to its low concentration, it will not have a substantial impact on the flame retardant modification process; wherein, the water-soluble polyester in the flame retardant solution can be removed by lowering the temperature of the flame retardant solution to reduce the solubility of the water-soluble polyester in the solution, so as to meet the control of the content of the water-soluble polyester component in the flame retardant solution, and the specific method is as follows: a flame retardant solution at 60 to 90°C is placed in a first flame retardant solution tank; the lower part of the first flame retardant solution tank is connected to the precipitation tank through pump I and a pipeline, the precipitation tank is connected to the configuration tank through pump II and a pipeline, and the configuration tank is connected to the upper part of the first flame retardant solution tank through pump III and a pipeline; the rotation speeds of pumps I and III are the same; a cooling mechanism is provided in the precipitation tank;

[0013] Initially, a flame retardant solution is placed in the configuration tank, and the temperature, volume and concentration are the same as those of the flame retardant solution in the first flame retardant solution tank, and the precipitation tank is empty. After the process is carried out for a period of time, the water-soluble polyester is dissolved in the first flame retardant solution tank, and the concentration of the flame retardant solution becomes smaller. Pumps I and III are turned on at the same time until the flame retardant solution in the configuration tank is replaced by the first flame retardant solution tank, and the original solution in the first flame retardant solution tank is replaced by the precipitation tank, and then pumps I and III are turned off; the precipitation temperature of the water-soluble polyester is 25-45°C, and the precipitation temperature of the flame retardant is 0-5°C. The temperature of the precipitation tank is first lowered to 25-45°C to precipitate the water-soluble polyester, and the water-soluble polyester is removed. The temperature is then lowered to 0-5°C to precipitate the flame retardant, and the flame retardant is removed. Then the remaining solvent in the precipitation tank is input into the empty configuration tank through pump II, and a flame retardant solution with the same concentration as the flame retardant solution in the first flame retardant solution tank is reconfigured, and its temperature is adjusted to be the same as that of the flame retardant solution;

[0014] Preferably, a drain outlet is provided at the bottom of the configuration tank. After the flame retardant solution in the configuration tank is replaced into the first flame retardant solution tank, the configuration tank is cleaned with a solvent, and the drain outlet is opened to discharge, and then the pump II is turned on.

[0015] The furan structure-modified polyester is obtained by reacting a mixed dibasic acid with an aliphatic diol, wherein the mixed dibasic acid is prepared by mixing a dibasic acid with furandicarboxylic acid in a molar ratio of 90 to 99:1 to 10.

[0016] The modified polyester type in the present invention is a saturated aliphatic polyester, and the raw materials required for polymerization are a mixed dibasic acid of a dibasic acid and furandicarboxylic acid and an aliphatic diol, wherein furandicarboxylic acid is used as the third monomer for copolymerization, wherein the furan structure in furandicarboxylic acid serves as a site that can form a chemical anchoring effect with the end group structure of the flame retardant;

[0017] The flame retardant is a phosphorus-containing flame retardant having a maleimide structure at the molecular chain end.

[0018] As the preferred technical solution:

[0019] The method for preparing a long-lasting flame-retardant polyester monofilament as described above, wherein the flame retardant is and / or

[0020] In the formula, R is a flame retardant structure containing phosphorus elements, and the structural formula is

[0021] In the method for preparing the long-lasting flame-retardant polyester monofilament as described above, the solvent of the flame retardant solution is water, and the mass concentration of the flame retardant in the flame retardant solution is 5-20%.

[0022] The method for preparing a long-lasting flame-retardant polyester monofilament as described above, wherein the dibasic acid is one or more of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid; the aliphatic diol is one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol and decanediol; and the furandicarboxylic acid is one or more of 2,5-furandicarboxylic acid and 3,4-furandicarboxylic acid.

[0023] In the method for preparing a long-lasting flame-retardant polyester monofilament as described in any one of the above items, the specific preparation steps of the furan structure-modified polyester are:

[0024] (1) Esterification reaction:

[0025] The mixed dibasic acid and the aliphatic diol are mixed and beaten, and then added into an esterification reaction kettle for esterification reaction. The pressure of the esterification reaction is 0.01-0.5 MPa, the reaction temperature is 220-260° C., the reaction time is 0.5-3 h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to the aliphatic diol is 1:1.05-1.10;

[0026] (2) Pre-polycondensation reaction:

[0027] Adding a catalyst, an antioxidant and a heat stabilizer to the product of step (1), and carrying out a pre-polycondensation reaction at 250-270° C. and 100-1000 Pa for 15-45 minutes to obtain a pre-polycondensation product with an intrinsic viscosity of ≤0.15 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 5-20 rpm;

[0028] (3) Final polycondensation reaction:

[0029] The precondensate obtained in step (2) is subjected to polycondensation reaction at 260-280° C. and 10-100 Pa for 1.5-3.5 hours to obtain a furan structure-containing modified polyester.

[0030] The method for preparing a long-lasting flame-retardant polyester monofilament as described above, wherein the catalyst is one or more of tetrabutyl titanate, titanium glycolate, antimony trioxide, antimony acetate or antimony glycolate; and the amount of the catalyst added is 100 to 500 ppm based on the mass of the dibasic acid;

[0031] The antioxidant is one or more of antioxidant 1010, antioxidant 168 or antioxidant 616; the amount of the antioxidant added is 0.001 to 0.03% of the mass of the dibasic acid;

[0032] The heat stabilizer is one or more of trimethyl phosphate, alkyl phosphate diester or tris(nonylphenyl)phosphite; the added amount of the heat stabilizer is 0.001-0.02% of the mass of the dibasic acid.

[0033] In the method for preparing the long-lasting flame-retardant polyester monofilament as described above, the specific preparation steps of the water-soluble polyester are as follows:

[0034] (1) mixing terephthalic acid (PTA), ethylene glycol (EG), SIPE (sodium bis(hydroxyethyl) sulfonate isophthalate) and a catalyst, and performing a first esterification reaction to obtain a first esterification product, wherein the first esterification reaction is performed under a nitrogen atmosphere, at a pressure of 0.01 to 0.5 MPa, at a temperature of 230 to 250° C., and for a time of 0.5 to 2.5 h;

[0035] (2) mixing the first esterification product and polyethylene glycol (PEG) and performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is performed at a pressure of 10 to 100 KPa, a temperature of 240 to 255° C., and a time of 0.5 to 2.5 h;

[0036] (3) subjecting the second esterification product to a pre-polycondensation reaction to obtain a pre-polycondensate, wherein the pre-polycondensation reaction is carried out under a pressure of 100 to 1000 Pa, a temperature of 250 to 260° C., and a time of 0.5 to 1.5 h;

[0037] (4) subjecting the precondensate to a final polycondensation reaction to obtain a water-soluble polyester melt, wherein the final polycondensation reaction is carried out at a pressure of 150 to 200 Pa, a temperature of 255 to 265° C., and a time of 1.5 to 2 h;

[0038] (5) Cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester.

[0039] The method for preparing a long-lasting flame-retardant polyester monofilament as described above comprises the following steps: in step (1), the molar ratio of terephthalic acid to ethylene glycol is 1:1.1 to 1:1.6; the amount of SIPE added is 10 to 30 wt% of the theoretical mass of the water-soluble polyester; the catalyst is one or more of tetrabutyl titanate, titanium glycol, antimony trioxide, antimony acetate and antimony glycol; and during the first esterification reaction, the amount of the catalyst added is 100 to 500 ppm of the mass of terephthalic acid.

[0040] In the method for preparing the long-lasting flame-retardant polyester monofilament as described above, the number average molecular weight of the polyethylene glycol in step (2) is 500 to 2500, and the amount of polyethylene glycol added is 10 to 50% of the mass of the first esterification product.

[0041] In the method for preparing a long-lasting flame-retardant polyester monofilament as described above, in step (4), the intrinsic viscosity of the water-soluble polyester melt is 0.40 to 0.60 dL / g.

[0042] The method for preparing a long-lasting flame-retardant polyester monofilament as described above, wherein the post-treatment is to perform a second stretching molding on the modified polyester raw yarn after the first stretching at 130°C to 200°C, and then heat-set at 135°C to 210°C, and the heat-setting time is 30s to 2min, and the heat-setting is performed to maintain a high degree of orientation and a high degree of crystallization.

[0043] A method for preparing a long-lasting flame-retardant polyester monofilament as described above, wherein in the first stretching, the linear speed of the first stretching roller is 15m / min to 25m / min, the linear speed of the second stretching roller is 80m / min to 120m / min, and the stretching multiple of the first stretching is 3 to 5 times;

[0044] In the second stretching forming, the linear speed of the third stretching roller is 120m / min to 150m / min, and the stretching multiple of the second stretching forming is 1 to 3 times;

[0045] The relaxation ratio during heat setting is 5% to 25%.

[0046] The present invention also provides a long-lasting flame-retardant polyester monofilament prepared by the method described in any of the above items, which is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, wherein the material of the polyester monofilament is a modified polyester containing a furan structure, the surface of the polyester monofilament has a "cavity" structure, and the "cavity" structure also contains a flame-retardant layer, the material of the flame-retardant layer is a phosphorus-containing flame retardant having a maleimide structure at one end and / or both ends, and the flame-retardant layer is chemically connected to the furan structure in the polyester monofilament via the maleimide structure.

[0047] The modified polyester monofilament precursor is cooled in a flame retardant solution after extrusion. During this process, the water-soluble polyester melt-blended with the modified polyester is dissolved, thereby forming a "cavity" structure on the surface of the precursor fiber due to the dissolution of the water-soluble polyester. The flame retardant containing a maleimide structure at the end group is chemically bonded to the furan ring structure in the modified polyester molecular chain through the Diels-Alder reaction of the end group structure. Therefore, the flame retardant is mostly connected to the precursor in the form of chemical bonds on the surface of the precursor and in the cavity structure, so that the flame retardant function of the surface of the precursor is modified, thereby forming a continuous, stable and durable flame retardant layer on the surface of the precursor.

[0048] As the preferred technical solution:

[0049] The long-lasting flame-retardant polyester monofilament has a tensile strength of 7 to 9 cN / dtex, and compared with an unmodified polyester sample produced under the same production process, the mechanical strength decreases by less than 10%, the limiting oxygen index (LOI) is ≥28%, and no dripping is generated during combustion; after 30 times of water washing, the limiting oxygen index (LOI) retention rate of the long-lasting flame-retardant polyester monofilament is more than 95%;

[0050] The flexural rigidity of the fabric made of long-lasting flame-retardant polyester monofilament is ≤2.0cN·cm, and the moisture permeability is ≥5000g·[m 2 ·(24h)] -1 , thermal resistance performance ≥ 25mk·m 2 ·w -1 ; The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of ≥90% and a K / S value of ≥25 at a dyeing temperature of 120°C.

[0051] The principle of the present invention is:

[0052] After the water-soluble polyester component is dissolved in the present invention, the specific surface area of ​​the modified polyester monofilament is increased, the "DA cross-linking" reaction rate of the flame-retardant component and the flame-retardant monofilament is improved, and the flame-retardant performance of the modified polyester monofilament is improved without affecting the mechanical properties of the modified polyester monofilament; different from the rough feel of some fibers or fabrics after the surface of the fabric is flame-retardantly treated, the "cavity" structure formed on the surface of the monofilament after the water-soluble polyester component is dissolved can improve the flexibility of the modified polyester monofilament, so that the modified polyester monofilament has a more comfortable touch during the application process, and at the same time, the "cavity" structure can also give the monofilament functions such as sweat conduction and warmth preservation, and water vapor can evaporate faster through the "cavity" structure to keep the fabric comfortable and dry, and the air retained in the "cavity" structure can also further reduce the thermal conductivity of the modified polyester monofilament fabric, thereby achieving the warmth preservation function; after the water-soluble polyester is dissolved, more holes are formed on the surface of the modified polyester monofilament to form a rough surface, so that the gloss of the modified polyester monofilament is softer, and the dyeing rate and dyeing depth of the modified polyester monofilament are improved.

[0053] The furan structure in the modified polyester exists in the main chain of the modified polyester molecule. Furan dicarboxylic acid is added as one of the reaction raw materials, and the modified polyester is prepared through polymerization reaction. Therefore, the furan structure in the modified polyester has the characteristics of uniform distribution, adjustable content, and intrinsic non-migration. The flame retardant structure is a phosphorus-containing flame retardant with a maleimide structure at one end and / or both ends. The maleimide structure reacts with the furan structure in the molecular chain structure of the polyester monofilament to form a chemical bond, so that the flame retardant is connected to the surface of the polyester monofilament to achieve the flame retardant function. In addition, the maleimide structure at one end and / or both ends of the flame retardant can form a synergistic flame retardant effect with the phosphorus-containing flame retardant due to its own nitrogen-containing and easy carbonization characteristics. While realizing the chemical bond connection between the flame retardant and the polyester monofilament, the flame retardant modification effect is further improved; among them, the cross-linking reaction mechanism of the furan structure and the maleimide structure "DA" is as follows:

[0054]

[0055] Beneficial Effects

[0056] (1) In the long-lasting flame-retardant polyester monofilament prepared by the present invention, the flame retardant is connected to the surface layer of the modified polyester raw yarn in the form of a chemical bond, thereby avoiding the adverse effects of the flame retardant components in copolymerization or blending modification on the arrangement of polyester molecular chains and the processing process;

[0057] (2) The present invention produces a long-lasting flame-retardant polyester monofilament, which is resistant to water washing during use, and the flame retardant will not be lost due to outward migration or breakage of the connection with the main chain. The flame retardant performance retention rate reaches more than 95%, achieving an excellent long-lasting flame retardant effect and meeting the use requirements;

[0058] (3) The present invention provides a method for preparing a long-lasting flame-retardant polyester monofilament, which utilizes a flame retardant to react with a furan structure on the fiber surface to produce a "DA" cross-linking reaction, so that the flame retardant is used on the fiber surface in the form of a chemical bond to prepare the flame-retardant polyester monofilament, thereby improving the durability of the flame-retardant polyester monofilament. Compared with the existing copolymerization flame-retardant modification technology, the amount of flame retardant used is reduced, the process flow is simple, and the production cost of the flame-retardant polyester monofilament can be effectively reduced. DETAILED DESCRIPTION

[0059] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0060] The testing method adopted by the present invention is as follows:

[0061] (1) Tensile strength: According to GB / T 14337-2022 “Test method for tensile properties of chemical staple fibers”, the tensile strength of monofilament fibers is evaluated by breaking strength.

[0062] (2) Limiting oxygen index: According to GB / T 5454-1997 “Textile combustion performance test oxygen index method”, the limiting oxygen index of the modified polyester monofilament sample was evaluated.

[0063] (3) Retention rate of limiting oxygen index of long-lasting flame retardant polyester monofilament after 30 washes: The washing test was carried out according to GB / T 8629-2017 Household washing and drying procedures for textile testing. Then, according to GB / T 5454-1997 Oxygen index method for testing burning performance of textiles, the limiting oxygen index of long-lasting flame retardant polyester monofilament after 30 washes was evaluated. The limiting oxygen index retention rate of the sample was obtained by dividing the limiting oxygen index before and after washing.

[0064] (4) Vertical combustion performance test: According to GB / T 5455-2014 “Combustion performance of textiles - Determination of vertical damage length, smoldering and combustion time”, test whether there is dripping during the combustion process.

[0065] (5) Bending stiffness: According to GB / T 18318.1-2009 “Determination of flexural properties of textiles - Inclined plane method”, the bending stiffness is used to evaluate the softness of the fabric. Bending stiffness G = m × C 3 ×10 -3 . m is the mass per unit area of ​​fabric, and C is the average bending length (cm).

[0066] (6) Moisture permeability: According to GB / T 12704.1-2009 “Test method for moisture permeability of textile fabrics - Moisture absorption method”, the moisture permeability of the fabric is used to evaluate the moisture conduction performance of the fabric.

[0067] (7) Thermal resistance performance: According to GB / T 11048-2018 “Determination of thermal resistance and moisture resistance of textiles under steady-state conditions of physiological comfort”, the thermal resistance index is used to evaluate the thermal insulation performance of the fabric.

[0068] (8) Dye uptake: According to GB / T 9337-2009 “Determination of dye uptake of disperse dyes at high temperature”, the dyeing performance of the fabric is evaluated by the dye uptake, where the dye uptake is calculated as follows:

[0069]

[0070] Among them, F is the high-temperature dyeing rate of disperse dyes, E1 is the optical density of the extract, E2 is the optical density of the dye solution, and m is the mass of the dyed fabric.

[0071] (9) K / S value: The dyeing depth of the fabric is measured by the K / S value, which can be calculated using the Kubelka-Munk formula:

[0072]

[0073] Where K is the absorption coefficient, S is the reflection coefficient, K / S is the apparent staining depth, 2R ∞ It is the reflectance value of dyed fabric at the maximum wavelength.

[0074] The flame retardant used in the embodiment of the present invention is obtained according to the preparation route shown below, by reacting the terminal hydroxyl group with the terminal carboxyl group, removing the byproduct water during the reaction so that the reaction proceeds in the forward direction, and the generated flame retardant contains a maleimide structure at one end or a maleimide structure at both ends.

[0075] Flame retardant preparation route (1):

[0076] In the flame retardant preparation route (1), a flame retardant is prepared by reacting a reactive flame retardant monomer with 2,5-dioxopyrrole-1-carboxylic acid. The reactive flame retardant monomer is one of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 2-(6-oxybenzo[c][2,1]benzophosphinyl)naphthalene-1,4-diol and 2-(6-oxybenzo[c][2,1]benzophosphinyl)-5-phenylbenzene-1,4-diol. The structural formulas thereof are shown below:

[0077]

[0078] The reaction equation is as follows, wherein the reaction of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide and 2,5-dioxopyrrole-1-carboxylic acid is taken as an example, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide and 2,5-dioxopyrrole-1-carboxylic acid are added to 1,4-dioxane solvent at a molar ratio of 1:2.2 to dissolve, wherein 1,4-dioxane is added at a mass ratio of 100:1 to the flame retardant monomer, the reaction raw materials are heated to 95° C. in a stirring device to react for 8 hours, and then the solvent and water are removed by reduced pressure distillation to obtain a flame retardant, which is used after being washed multiple times to remove the residual solvent;

[0079]

[0080] Flame retardant preparation route (2):

[0081] In the flame retardant preparation route (2), a flame retardant is prepared by reacting a reactive flame retardant monomer with 1-hydroxypyrrole-2,5-dione. The reactive flame retardant monomer is one of [(6-oxo-6H-dibenzo[c,e][1,2]oxaphosphorin-6-yl)methyl]succinic acid, 2-(6-oxobenzo[c][2,1]benzophosphinyl)succinic acid and 2-carboxyethylphenylphosphinic acid. The structural formulas thereof are shown below:

[0082] The reaction equation is as follows, wherein the reaction of 2-(6-oxobenzo[c][2,1]benzophosphine oxide-6-yl)succinic acid and 1-hydroxypyrrole-2,5-dione is taken as an example, 2-(6-oxobenzo[c][2,1]benzophosphine oxide-6-yl)succinic acid and 1-hydroxypyrrole-2,5-dione are added to 1,4-dioxane solvent at a molar ratio of 1:2.2 to dissolve, wherein 1,4-dioxane is added at a mass ratio of 100:1 to the flame retardant monomer, the reaction raw materials are heated to 95° C. in a stirring device for reaction for 8 hours, and then the solvent and water are removed by reduced pressure distillation to obtain a flame retardant, which is used after being washed multiple times to remove the residual solvent;

[0083]

[0084] Example 1

[0085] A method for preparing a long-lasting flame-retardant polyester monofilament, comprising the following specific steps:

[0086] (1) Preparation of furan-containing modified polyester:

[0087] (1.1) Esterification reaction:

[0088] Terephthalic acid and 2,5-furandicarboxylic acid are prepared in a molar ratio of 90:10 to obtain a mixed dibasic acid; the mixed dibasic acid and ethylene glycol are mixed and slurried, and then added into an esterification reactor for esterification reaction, the esterification reaction pressure is 0.01MPa, the reaction temperature is 220°C, the reaction time is 3h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to the ethylene glycol is 1:1.05;

[0089] (1.2) Pre-condensation reaction:

[0090] Tetrabutyl titanate, antioxidant 1010 and trimethyl phosphate are added to the product of step (1.1), and a pre-polycondensation reaction is carried out at 250° C. and 100 Pa for 45 minutes to obtain a pre-polycondensation product with an intrinsic viscosity of 0.13 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 5 rpm; based on the mass of terephthalic acid, the amount of tetrabutyl titanate added is 10 ppm; the amount of antioxidant 1010 added is 0.001% of the mass of terephthalic acid; and the amount of trimethyl phosphate added is 0.001% of the mass of terephthalic acid;

[0091] (1.3) Final polycondensation reaction:

[0092] The precondensate obtained in step (1.2) is subjected to polycondensation reaction at 260° C. and 10 Pa for 3.5 hours to obtain a furan structure-modified polyester, wherein the glass transition temperature of the furan structure-modified polyester is 63° C.;

[0093] (2) Preparation of water-soluble polyester:

[0094] (2.1) terephthalic acid, ethylene glycol, SIPE and tetrabutyl titanate are mixed and subjected to a first esterification reaction to obtain a first esterification product; wherein the first esterification reaction is carried out under a nitrogen atmosphere, at a pressure of 0.01 MPa, a temperature of 230° C., and a time of 2.5 h;

[0095] The molar ratio of terephthalic acid to ethylene glycol is 1:1.1; the amount of SIPE added is 10wt% of the theoretical mass of the water-soluble polyester; the amount of tetrabutyl titanate added during the first esterification reaction is 15ppm of the mass of terephthalic acid;

[0096] (2.2) mixing the first esterification product and polyethylene glycol, and then performing a second esterification reaction to obtain a second esterification product. The second esterification reaction is carried out at a pressure of 10 KPa, a temperature of 240° C., and a time of 2.5 h. The number average molecular weight of the polyethylene glycol is 1500, and the amount of polyethylene glycol added is 10% of the mass of the first esterification product.

[0097] (2.3) subjecting the second esterification product to a pre-condensation reaction to obtain a pre-condensation polymer, wherein the pre-condensation reaction pressure is 150 Pa, the temperature is 255° C., and the time is 2 h;

[0098] (2.4) subjecting the pre-condensate to a final polycondensation reaction to obtain a water-soluble polyester melt having an intrinsic viscosity of 0.4 dL / g. The final polycondensation reaction is carried out at a pressure of 150 Pa, a temperature of 255° C., and a time of 2 h.

[0099] (2.5) cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester;

[0100] (3) firstly, melt-blending the furan structure-modified polyester obtained in step (1) and the water-soluble polyester obtained in step (2) to obtain modified polyester precursor yarns by extrusion spinning, then treating the modified polyester precursor yarns in a flame retardant aqueous solution at 60° C. to dissolve the water-soluble polyester component in the modified polyester precursor yarns in the flame retardant aqueous solution, and then placing the treated modified polyester precursor yarns in a flame retardant aqueous solution at a temperature of 65° C. for a first stretching;

[0101] Among them, the flame retardant is The mass concentration of the flame retardant in the flame retardant aqueous solution is 5%; the stretching ratio of the first stretching is 3 times;

[0102] (4) The modified polyester raw yarn after the first stretching is stretched for a second time at 130° C., and then heat-set at 135° C. for 30 seconds to obtain a long-lasting flame-retardant polyester monofilament; the stretching ratio of the second stretching is 1 times; and the relaxation ratio of the heat-setting process is 5%.

[0103] The finally obtained long-lasting flame-retardant polyester monofilament is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, the polyester monofilament is made of a furan-containing modified polyester, the surface of the polyester monofilament has a "cavity" structure, the flame-retardant layer is made of a phosphorus-containing flame retardant (i.e., a flame retardant in a flame retardant aqueous solution) having a maleimide structure at one end and both ends, and the flame-retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure; the tensile strength of the long-lasting flame-retardant polyester monofilament is 7.1 cN / dtex, the limiting oxygen index is 28.5%, and no dripping is generated during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is 98%; the flexural rigidity of the fabric made of the long-lasting flame-retardant polyester monofilament is 1.3 cN·cm, and the moisture permeability is 5050 g·[m 2 ·(24h)] -1 , thermal resistance performance is 25mk·m 2 ·w -1 The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of 95% and a K / S value of 29 at a dyeing temperature of 120°C.

[0104] Example 2

[0105] A method for preparing a long-lasting flame-retardant polyester monofilament, comprising the following specific steps:

[0106] (1) Preparation of furan-containing modified polyester:

[0107] (1.1) Esterification reaction:

[0108] Isophthalic acid and 3,4-furandicarboxylic acid are prepared in a molar ratio of 91:9 to obtain a mixed dibasic acid; the mixed dibasic acid and propylene glycol are mixed and beaten, and then added into an esterification reactor for esterification reaction, the esterification reaction pressure is 0.05MPa, the reaction temperature is 225°C, the reaction time is 2.5h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to propylene glycol is 1:1.06;

[0109] (1.2) Pre-polycondensation reaction:

[0110] Adding titanium glycolate, antioxidant 168 and alkyl phosphate diester to the product of step (1.1), carrying out a pre-polycondensation reaction at 255°C and 200 Pa for 40 minutes, to obtain a pre-polycondensation product with a characteristic viscosity of 0.14 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 5 rpm; based on the mass of isophthalic acid, the amount of titanium glycolate added is 15 ppm; the amount of antioxidant 168 added is 0.005% of the mass of isophthalic acid; and the amount of alkyl phosphate diester added is 0.005% of the mass of isophthalic acid;

[0111] (1.3) Final polycondensation reaction:

[0112] The precondensate obtained in step (1.2) is subjected to polycondensation reaction at 265° C. and 20 Pa for 3 h to obtain a furan structure-modified polyester, wherein the furan structure-modified polyester has a glass transition temperature of 65° C.;

[0113] (2) Preparation of water-soluble polyester:

[0114] (2.1) mixing terephthalic acid, ethylene glycol, SIPE and titanium glycol and performing a first esterification reaction to obtain a first esterification product; wherein the first esterification reaction is carried out under a nitrogen atmosphere, at a pressure of 0.1 MPa, a temperature of 235° C., and a time of 2 h;

[0115] The molar ratio of terephthalic acid to ethylene glycol is 1:1.2; the amount of SIPE added is 15wt% of the theoretical mass of the water-soluble polyester; the amount of titanium glycol added during the first esterification reaction is 25ppm of the mass of terephthalic acid;

[0116] (2.2) mixing the first esterification product and polyethylene glycol and performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is carried out at a pressure of 20 KPa, a temperature of 245° C., and a time of 2 h; wherein the number average molecular weight of the polyethylene glycol is 1600, and the amount of polyethylene glycol added is 20% of the mass of the first esterification product;

[0117] (2.3) subjecting the second esterification product to a pre-condensation reaction to obtain a pre-condensation polymer, wherein the pre-condensation reaction pressure is 160 Pa, the temperature is 255° C., and the time is 2 h;

[0118] (2.4) subjecting the pre-condensate to a final polycondensation reaction to obtain a water-soluble polyester melt having an intrinsic viscosity of 0.5 dL / g. The final polycondensation reaction is carried out at a pressure of 160 Pa, a temperature of 255° C., and a time of 2 h.

[0119] (2.5) cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester;

[0120] (3) firstly, melt-blending the furan structure-modified polyester obtained in step (1) and the water-soluble polyester obtained in step (2) to obtain modified polyester precursor yarn by extrusion spinning, then treating the modified polyester precursor yarn in a flame retardant aqueous solution at 63° C. to dissolve the water-soluble polyester component in the modified polyester precursor yarn in the flame retardant aqueous solution, and then placing the treated modified polyester precursor yarn in a flame retardant aqueous solution at a temperature of 67° C. for a first stretching;

[0121] Among them, the flame retardant is The mass concentration of the flame retardant in the flame retardant aqueous solution is 7%; the stretching ratio of the first stretching is 3.5 times;

[0122] (4) The modified polyester raw yarn after the first stretching is stretched for a second time at 140° C., and then heat-set at 150° C. for 45 seconds to obtain a long-lasting flame-retardant polyester monofilament; the stretching ratio of the second stretching is 1.5 times; and the relaxation ratio of the heat-setting process is 8%.

[0123] The finally obtained long-lasting flame-retardant polyester monofilament is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, the polyester monofilament is made of a furan-modified polyester, the surface of the polyester monofilament has a "cavity" structure, the flame-retardant layer is made of a phosphorus-containing flame retardant (i.e., a flame retardant in a flame retardant aqueous solution) having a maleimide structure at one end and both ends, and the flame-retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure; the tensile strength of the long-lasting flame-retardant polyester monofilament is 7.3 cN / dtex, the limiting oxygen index is 29%, and no dripping is generated during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is 98.50%; the flexural rigidity of the fabric made of the long-lasting flame-retardant polyester monofilament is 1.6 cN·cm, and the moisture permeability is 5100 g·[m 2 ·(24h)] -1 , thermal resistance performance is 25.5mk·m 2 ·w -1 The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of 93.50% and a K / S value of 28 at a dyeing temperature of 120°C.

[0124] Example 3

[0125] A method for preparing a long-lasting flame-retardant polyester monofilament, comprising the following specific steps:

[0126] (1) Preparation of furan-containing modified polyester:

[0127] (1.1) Esterification reaction:

[0128] Succinic acid and 2,5-furandicarboxylic acid are prepared in a molar ratio of 93:7 to obtain a mixed dibasic acid; the mixed dibasic acid and butanediol are mixed and beaten, and then added into an esterification reactor for esterification reaction. The esterification reaction pressure is 0.1MPa, the reaction temperature is 230°C, the reaction time is 2h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to butanediol is 1:1.07;

[0129] (1.2) Pre-condensation reaction:

[0130] Add antimony trioxide, antioxidant 616 and tris(nonylphenyl)phosphite to the product of step (1.1), and carry out a pre-polycondensation reaction at 260°C and 400 Pa for 35 minutes to obtain a pre-polycondensation product with an intrinsic viscosity of 0.12 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 10 rpm; the amount of antimony trioxide added is 250 ppm based on the mass of succinic acid; the amount of antioxidant 616 added is 0.01% of the mass of succinic acid; and the amount of tris(nonylphenyl)phosphite added is 0.01% of the mass of succinic acid;

[0131] (1.3) Final polycondensation reaction:

[0132] The precondensate obtained in step (1.2) is subjected to polycondensation reaction at 270° C. and 30 Pa for 2.5 h to obtain a furan structure-modified polyester, wherein the glass transition temperature of the furan structure-modified polyester is 70° C.;

[0133] (2) Preparation of water-soluble polyester:

[0134] (2.1) mixing terephthalic acid, ethylene glycol, SIPE and antimony trioxide and performing a first esterification reaction to obtain a first esterification product; wherein the first esterification reaction is carried out under a nitrogen atmosphere, at a pressure of 0.2 MPa, a temperature of 240° C., and a time of 1.5 h;

[0135] The molar ratio of terephthalic acid to ethylene glycol is 1:1.3; the amount of SIPE added is 30wt% of the theoretical mass of the water-soluble polyester; the amount of antimony trioxide added during the first esterification reaction is 200ppm of the mass of terephthalic acid;

[0136] (2.2) mixing the first esterification product and polyethylene glycol and performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is carried out at a pressure of 30 KPa, a temperature of 250° C., and a time of 1.5 h; wherein the number average molecular weight of the polyethylene glycol is 1800, and the amount of polyethylene glycol added is 30% of the mass of the first esterification product;

[0137] (2.3) subjecting the second esterification product to a pre-condensation reaction to obtain a pre-condensation polymer, wherein the pre-condensation reaction pressure is 170 Pa, the temperature is 260° C., and the time is 1.75 h;

[0138] (2.4) subjecting the pre-condensate to a final polycondensation reaction to obtain a water-soluble polyester melt having an intrinsic viscosity of 0.6 dL / g. The final polycondensation reaction is carried out at a pressure of 170 Pa, a temperature of 260° C., and a time of 1.75 h.

[0139] (2.5) cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester;

[0140] (3) firstly, melt-blending the furan structure-modified polyester obtained in step (1) and the water-soluble polyester obtained in step (2) to obtain modified polyester precursor yarn by extrusion spinning, then treating the modified polyester precursor yarn in a flame retardant aqueous solution at 68° C. to dissolve the water-soluble polyester component in the modified polyester precursor yarn in the flame retardant aqueous solution, and then placing the treated modified polyester precursor yarn in a flame retardant aqueous solution at a temperature of 72° C. for a first stretching;

[0141] Among them, the flame retardant is The mass concentration of the flame retardant in the flame retardant aqueous solution is 10%; the stretching ratio of the first stretching is 4 times;

[0142] (4) The modified polyester raw yarn after the first stretching is stretched for a second time at 150° C., and then heat-set at 165° C. for 1 minute to obtain a long-lasting flame-retardant polyester monofilament; the stretching ratio of the second stretching is 2 times; and the relaxation ratio of the heat-setting process is 10%.

[0143] The finally obtained long-lasting flame-retardant polyester monofilament is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, the polyester monofilament is made of a furan-containing modified polyester, the surface of the polyester monofilament has a "cavity" structure, the flame-retardant layer is made of a phosphorus-containing flame retardant (i.e., a flame retardant in a flame retardant aqueous solution) having a maleimide structure at one end and both ends, and the flame-retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure; the tensile strength of the long-lasting flame-retardant polyester monofilament is 7.5 cN / dtex, the limiting oxygen index is 29.5%, and no dripping is generated during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is 97.50%; the flexural rigidity of the fabric made of the long-lasting flame-retardant polyester monofilament is 1.1 cN·cm, and the moisture permeability is 5150 g·[m 2 ·(24h)] -1 , thermal resistance performance is 27mk·m 2 ·w -1 The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of 92% and a K / S value of 26.5 at a dyeing temperature of 120°C.

[0144] Example 4

[0145] A method for preparing a long-lasting flame-retardant polyester monofilament, comprising the following specific steps:

[0146] (1) Preparation of furan-containing modified polyester:

[0147] (1.1) Esterification reaction:

[0148] Glutaric acid and 3,4-furandicarboxylic acid are prepared in a molar ratio of 95:5 to obtain a mixed dibasic acid; the mixed dibasic acid and pentanediol are mixed and beaten, and then added into an esterification reaction kettle for esterification reaction. The esterification reaction pressure is 0.2MPa, the reaction temperature is 240°C, the reaction time is 1.5h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to pentanediol is 1:1.08;

[0149] (1.2) Pre-polycondensation reaction:

[0150] Add antimony acetate, antioxidant 1010 and trimethyl phosphate to the product of step (1.1), and carry out a pre-polycondensation reaction at 265° C. and 500 Pa for 30 minutes to obtain a pre-polycondensation product with an intrinsic viscosity of 0.125 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 10 rpm; the amount of antimony acetate added is 300 ppm based on the mass of glutaric acid; the amount of antioxidant 1010 added is 0.015% of the mass of glutaric acid; and the amount of trimethyl phosphate added is 0.015% of the mass of glutaric acid;

[0151] (1.3) Final polycondensation reaction:

[0152] The precondensate obtained in step (1.2) is subjected to polycondensation reaction at 275° C. and 50 Pa for 2 h to obtain a furan structure-modified polyester, wherein the furan structure-modified polyester has a glass transition temperature of 76° C.;

[0153] (2) Preparation of water-soluble polyester:

[0154] (2.1) mixing terephthalic acid, ethylene glycol, SIPE and antimony acetate and performing a first esterification reaction to obtain a first esterification product; wherein the first esterification reaction is carried out under a nitrogen atmosphere, at a pressure of 0.3 MPa, a temperature of 245° C., and a time of 1 h;

[0155] The molar ratio of terephthalic acid to ethylene glycol is 1:1.4; the amount of SIPE added is 25wt% of the theoretical mass of the water-soluble polyester; the amount of antimony acetate added during the first esterification reaction is 250ppm of the mass of terephthalic acid;

[0156] (2.2) mixing the first esterification product and polyethylene glycol, and then performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is carried out at a pressure of 50 KPa, a temperature of 255° C., and a time of 1 h; wherein the number average molecular weight of the polyethylene glycol is 2000, and the amount of polyethylene glycol added is 40% of the mass of the first esterification product;

[0157] (2.3) subjecting the second esterification product to a pre-condensation reaction to obtain a pre-condensation polymer, wherein the pre-condensation reaction pressure is 180 Pa, the temperature is 260° C., and the time is 1.75 h;

[0158] (2.4) subjecting the pre-condensate to a final polycondensation reaction to obtain a water-soluble polyester melt having an intrinsic viscosity of 0.45 dL / g. The final polycondensation reaction is carried out at a pressure of 180 Pa, a temperature of 260° C., and a time of 1.75 h.

[0159] (2.5) cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester;

[0160] (3) firstly, melt-blending the furan structure-modified polyester obtained in step (1) and the water-soluble polyester obtained in step (2) to obtain modified polyester precursor yarn by extrusion spinning, then treating the modified polyester precursor yarn in a flame retardant aqueous solution at 74° C. to dissolve the water-soluble polyester component in the modified polyester precursor yarn in the flame retardant aqueous solution, and then placing the treated modified polyester precursor yarn in a flame retardant aqueous solution at a temperature of 79° C. for a first stretching;

[0161] Among them, the flame retardant is The mass concentration of the flame retardant in the flame retardant aqueous solution is 12%; the stretching ratio of the first stretching is 4.5 times;

[0162] (4) The modified polyester raw yarn after the first stretching is stretched for a second time at 160° C., and then heat-set at 180° C. for 75 seconds to obtain a long-lasting flame-retardant polyester monofilament; the stretching ratio of the second stretching is 2.5 times; and the relaxation ratio of the heat-setting process is 12%.

[0163] The finally obtained long-lasting flame-retardant polyester monofilament is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, the polyester monofilament is made of a furan-containing modified polyester, the surface of the polyester monofilament has a "cavity" structure, the flame-retardant layer is made of a phosphorus-containing flame retardant (i.e., a flame retardant in a flame retardant aqueous solution) having a maleimide structure at one end and both ends, and the flame-retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure; the tensile strength of the long-lasting flame-retardant polyester monofilament is 7.7 cN / dtex, the limiting oxygen index is 30%, and no dripping is generated during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is 96%; the flexural rigidity of the fabric made of the long-lasting flame-retardant polyester monofilament is 1.4 cN·cm, and the moisture permeability is 5200 g·[m 2 ·(24h)] -1 , thermal resistance performance is 26.5mk·m 2 ·w -1 The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of 92.5% and a K / S value of 27 at a dyeing temperature of 120°C.

[0164] Example 5

[0165] A method for preparing a long-lasting flame-retardant polyester monofilament, comprising the following specific steps:

[0166] (1) Preparation of furan-containing modified polyester:

[0167] (1.1) Esterification reaction:

[0168] Adipic acid and 2,5-furandicarboxylic acid are prepared in a molar ratio of 96:4 to obtain a mixed dibasic acid; the mixed dibasic acid and hexylene glycol are mixed and beaten, and then added into an esterification reaction kettle for esterification reaction. The esterification reaction pressure is 0.3 MPa, the reaction temperature is 250° C., the reaction time is 1 h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to hexylene glycol is 1:1.09;

[0169] (1.2) Pre-polycondensation reaction:

[0170] Add antimony glycol, antioxidant 168 and alkyl phosphate diester to the product of step (1.1), and carry out a pre-polycondensation reaction at 270°C and 600 Pa for 25 minutes to obtain a pre-polycondensation product with an intrinsic viscosity of 0.135 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 15 rpm; based on the mass of adipic acid, the amount of antimony glycol added is 400 ppm; the amount of antioxidant 168 added is 0.02% of the mass of adipic acid; and the amount of alkyl phosphate diester added is 0.02% of the mass of adipic acid;

[0171] (1.3) Final polycondensation reaction:

[0172] The precondensate obtained in step (1.2) is subjected to polycondensation reaction at 280° C. and 60 Pa for 1.5 h to obtain a furan structure-modified polyester, wherein the glass transition temperature of the furan structure-modified polyester is 82° C.;

[0173] (2) Preparation of water-soluble polyester:

[0174] (2.1) mixing terephthalic acid, ethylene glycol, SIPE and ethylene glycol antimony and performing a first esterification reaction to obtain a first esterification product; wherein the first esterification reaction is carried out under a nitrogen atmosphere, at a pressure of 0.4 MPa, a temperature of 250° C., and a time of 0.5 h;

[0175] The molar ratio of terephthalic acid to ethylene glycol is 1:1.5; the amount of SIPE added is 30wt% of the theoretical mass of the water-soluble polyester; the amount of ethylene glycol antimony added during the first esterification reaction is 300ppm of the mass of terephthalic acid;

[0176] (2.2) mixing the first esterification product and polyethylene glycol and performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is carried out at a pressure of 60 KPa, a temperature of 240° C., and a time of 0.5 h; wherein the number average molecular weight of the polyethylene glycol is 2200, and the amount of polyethylene glycol added is 40% of the mass of the first esterification product;

[0177] (2.3) subjecting the second esterification product to a pre-condensation reaction to obtain a pre-condensation polymer, wherein the pre-condensation reaction pressure is 190 Pa, the temperature is 265° C., and the time is 1.5 h;

[0178] (2.4) subjecting the precondensate to a final polycondensation reaction to obtain a water-soluble polyester melt having an intrinsic viscosity of 0.55 dL / g. The final polycondensation reaction is carried out at a pressure of 190 Pa, a temperature of 265° C., and a time of 1.5 h.

[0179] (2.5) cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester;

[0180] (3) firstly, melt-blending the furan structure-containing modified polyester obtained in step (1) and the water-soluble polyester obtained in step (2) to obtain modified polyester precursor yarns by extrusion spinning, then treating the modified polyester precursor yarns in a flame retardant aqueous solution at 80° C. to dissolve the water-soluble polyester component in the modified polyester precursor yarns in the flame retardant aqueous solution, and then placing the treated modified polyester precursor yarns in a flame retardant aqueous solution at a temperature of 85° C. for a first stretching;

[0181] Among them, the flame retardant is The mass concentration of the flame retardant in the flame retardant aqueous solution is 15%; the stretching ratio of the first stretching is 5 times;

[0182] (4) The modified polyester raw yarn after the first stretching is stretched for a second time at 170°C, and then heat-set at 195°C for 90s to obtain a long-lasting flame-retardant polyester monofilament; the stretching ratio of the second stretching is 3 times; and the relaxation ratio of the heat-setting process is 16%.

[0183] The finally obtained long-lasting flame-retardant polyester monofilament is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, the polyester monofilament is made of a furan-modified polyester, the surface of the polyester monofilament has a "cavity" structure, the flame-retardant layer is made of a phosphorus-containing flame retardant (i.e., a flame retardant in a flame retardant aqueous solution) having a maleimide structure at one end and both ends, and the flame-retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure; the tensile strength of the long-lasting flame-retardant polyester monofilament is 8.1 cN / dtex, the limiting oxygen index is 29.5%, and no dripping is generated during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is 96.50%; the flexural rigidity of the fabric made of the long-lasting flame-retardant polyester monofilament is 1.5 cN·cm, and the moisture permeability is 5250 g·[m 2 ·(24h)] -1 , thermal resistance performance is 26mk·m 2 ·w -1 The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of 90.5% and a K / S value of 25 at a dyeing temperature of 120°C.

[0184] Example 6

[0185] A method for preparing a long-lasting flame-retardant polyester monofilament, comprising the following specific steps:

[0186] (1) Preparation of furan-containing modified polyester:

[0187] (1.1) Esterification reaction:

[0188] A mixture of heptanediol and suberic acid in a mass ratio of 1:1 and 3,4-furandicarboxylic acid in a molar ratio of 98:2 are prepared to obtain a mixed dibasic acid; the mixed dibasic acid is then mixed with a mixture of heptanediol and octanediol in a mass ratio of 1:1, and the mixture is added to an esterification reactor for esterification reaction. The esterification reaction pressure is 0.4 MPa, the reaction temperature is 255° C., the reaction time is 0.5 h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to the mixture of heptanediol and octanediol in a mass ratio of 1:1 is 1:1.1;

[0189] (1.2) Pre-polycondensation reaction:

[0190] Tetrabutyl titanate, antioxidant 616 and tris(nonylphenyl)phosphite are added to the product of step (1.1), and a pre-polycondensation reaction is carried out at 270°C and 800 Pa for 20 minutes to obtain a pre-polycondensation product with a characteristic viscosity of 0.145 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 20 rpm; based on the mass of pimelic acid and suberic acid, the amount of tetrabutyl titanate added is 50 ppm; the amount of antioxidant 616 added is 0.025% of the mass of pimelic acid and suberic acid; the amount of tris(nonylphenyl)phosphite added is 0.02% of the mass of pimelic acid and suberic acid;

[0191] (1.3) Final polycondensation reaction:

[0192] The precondensate obtained in step (1.2) is subjected to polycondensation reaction at 280° C. and 80 Pa for 1.5 h to obtain a furan structure-modified polyester, wherein the glass transition temperature of the furan structure-modified polyester is 83° C.;

[0193] (2) Preparation of water-soluble polyester:

[0194] (2.1) terephthalic acid, ethylene glycol, SIPE and tetrabutyl titanate are mixed and subjected to a first esterification reaction to obtain a first esterification product; wherein the first esterification reaction is carried out under a nitrogen atmosphere, at a pressure of 0.5 MPa, a temperature of 250° C., and a time of 0.5 h;

[0195] The molar ratio of terephthalic acid to ethylene glycol is 1:1.6; the amount of SIPE added is 30wt% of the theoretical mass of the water-soluble polyester; the amount of tetrabutyl titanate added during the first esterification reaction is 45ppm of the mass of terephthalic acid;

[0196] (2.2) mixing the first esterification product and polyethylene glycol and performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is carried out at a pressure of 80 KPa, a temperature of 245° C., and a time of 0.5 h; wherein the number average molecular weight of the polyethylene glycol is 2300, and the amount of polyethylene glycol added is 50% of the mass of the first esterification product;

[0197] (2.3) subjecting the second esterification product to a pre-condensation reaction to obtain a pre-condensation polymer, wherein the pre-condensation reaction is carried out at a pressure of 200 Pa, a temperature of 265° C., and a time of 1.5 h;

[0198] (2.4) subjecting the pre-condensate to a final polycondensation reaction to obtain a water-soluble polyester melt having an intrinsic viscosity of 0.48 dL / g. The final polycondensation reaction is carried out at a pressure of 200 Pa, a temperature of 265° C., and a time of 1.5 h.

[0199] (2.5) cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester;

[0200] (3) firstly, melt-blending the furan structure-containing modified polyester obtained in step (1) and the water-soluble polyester obtained in step (2) to obtain modified polyester precursor yarn, then treating the modified polyester precursor yarn in a flame retardant aqueous solution at 81° C. to dissolve the water-soluble polyester component in the modified polyester precursor yarn in the flame retardant aqueous solution, and then placing the treated modified polyester precursor yarn in a flame retardant aqueous solution at a temperature of 86° C. for a first stretching;

[0201] Among them, the flame retardant is The mass concentration of the flame retardant in the flame retardant aqueous solution is 18%; the stretching ratio of the first stretching is 3 times;

[0202] (4) The modified polyester raw yarn after the first stretching is stretched for a second time at 180°C, and then heat-set at 200°C for 105s to obtain a long-lasting flame-retardant polyester monofilament; the stretching ratio of the second stretching is 1; and the relaxation ratio of the heat-setting process is 17%.

[0203] The finally obtained long-lasting flame-retardant polyester monofilament is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, the polyester monofilament is made of a furan-containing modified polyester, the surface of the polyester monofilament has a "cavity" structure, the flame-retardant layer is made of a phosphorus-containing flame retardant (i.e., a flame retardant in a flame retardant aqueous solution) having a maleimide structure at one end and both ends, and the flame-retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure; the tensile strength of the long-lasting flame-retardant polyester monofilament is 8.5 cN / dtex, the limiting oxygen index is 29%, and no dripping is generated during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is 97%; the flexural rigidity of the fabric made of the long-lasting flame-retardant polyester monofilament is 1.8 cN·cm, and the moisture permeability is 5300 g·[m 2 ·(24h)] -1 , thermal resistance performance is 28mk·m 2 ·w -1 The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of 91% and a K / S value of 25.5 at a dyeing temperature of 120°C.

[0204] Example 7

[0205] A method for preparing a long-lasting flame-retardant polyester monofilament, comprising the following specific steps:

[0206] (1) Preparation of furan-containing modified polyester:

[0207] (1.1) Esterification reaction:

[0208] A mixture of azelaic acid and sebacic acid in a mass ratio of 1:1 and a mixture of 2,5-furandicarboxylic acid and 3,4-furandicarboxylic acid in a mass ratio of 1:1 are prepared in a molar ratio of 99:1 to obtain a mixed dibasic acid; the mixed dibasic acid is then mixed with a mixture of nonanediol and decanediol in a mass ratio of 1:1, and the mixture is added to an esterification reactor for esterification reaction. The pressure of the esterification reaction is 0.5 MPa, the reaction temperature is 260°C, the reaction time is 0.5 h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to nonanediol and decanediol is 1:1.0;

[0209] (1.2) Pre-polycondensation reaction:

[0210] A mixture of antimony acetate and antimony glycol in a mass ratio of 1:1, a mixture of antioxidant 168 and antioxidant 616 in a mass ratio of 1:1, and a mixture of trimethyl phosphate and alkyl phosphate diester in a mass ratio of 1:1 are added to the product of step (1.1), and a pre-polycondensation reaction is carried out at 270°C and 1000 Pa for 15 minutes to obtain a pre-polycondensation product with a characteristic viscosity of 0.15 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 20 rpm; based on the mass of azelaic acid and sebacic acid, the amount of antimony acetate and antimony glycol added is 500 ppm; the amount of antioxidant 168 and antioxidant 616 added is 0.03% of the mass of azelaic acid and sebacic acid; the amount of trimethyl phosphate and alkyl phosphate diester added is 0.02% of the mass of azelaic acid and sebacic acid;

[0211] (1.3) Final polycondensation reaction:

[0212] The precondensate obtained in step (1.2) is subjected to polycondensation reaction at 280° C. and 100 Pa for 1.5 h to obtain a furan structure-modified polyester, wherein the glass transition temperature of the furan structure-modified polyester is 94° C.;

[0213] (2) Preparation of water-soluble polyester:

[0214] (2.1) mixing terephthalic acid, ethylene glycol, SIPE and a mixture of antimony acetate and antimony ethylene glycol in a mass ratio of 1:1, and performing a first esterification reaction to obtain a first esterification product; wherein the first esterification reaction is carried out under a nitrogen atmosphere, at a pressure of 0.5 MPa, a temperature of 250° C., and a time of 0.5 h;

[0215] The molar ratio of terephthalic acid to ethylene glycol is 1:1.6; the amount of SIPE added is 25wt% of the theoretical mass of the water-soluble polyester; the amount of antimony acetate and antimony glycol added during the first esterification reaction is 500ppm of the mass of terephthalic acid;

[0216] (2.2) mixing the first esterification product and polyethylene glycol and performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is carried out at a pressure of 100 KPa, a temperature of 250° C., and a time of 0.5 h; wherein the number average molecular weight of the polyethylene glycol is 2500, and the amount of polyethylene glycol added is 45% of the mass of the first esterification product;

[0217] (2.3) subjecting the second esterification product to a pre-condensation reaction to obtain a pre-condensation polymer, wherein the pre-condensation reaction is carried out at a pressure of 200 Pa, a temperature of 265° C., and a time of 1.5 h;

[0218] (2.4) subjecting the pre-condensate to a final polycondensation reaction to obtain a water-soluble polyester melt having an intrinsic viscosity of 0.52 dL / g. The final polycondensation reaction is carried out at a pressure of 200 Pa, a temperature of 265° C., and a time of 1.5 h.

[0219] (2.5) cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester;

[0220] (3) firstly, melt-blending the furan structure-modified polyester obtained in step (1) and the water-soluble polyester obtained in step (2) to obtain modified polyester precursor yarns by extrusion spinning, then treating the modified polyester precursor yarns in a flame retardant aqueous solution at 91° C. to dissolve the water-soluble polyester component in the modified polyester precursor yarns in the flame retardant aqueous solution, and then placing the treated modified polyester precursor yarns in a flame retardant aqueous solution at a temperature of 97° C. for a first stretching;

[0221] Among them, the flame retardant is The mass concentration of the flame retardant in the flame retardant aqueous solution is 20%; the stretching ratio of the first stretching is 5 times;

[0222] (4) The modified polyester raw yarn after the first stretching is stretched for a second time at 200° C., and then heat-set at 210° C. for 2 minutes to obtain a long-lasting flame-retardant polyester monofilament; the stretching ratio of the second stretching is 3 times; and the relaxation ratio of the heat-setting process is 22%.

[0223] The finally obtained long-lasting flame-retardant polyester monofilament is composed of a polyester monofilament and a flame-retardant layer distributed on the surface of the polyester monofilament, the polyester monofilament is made of a furan-modified polyester, the surface of the polyester monofilament has a "cavity" structure, the flame-retardant layer is made of a phosphorus-containing flame retardant (i.e., a flame retardant in a flame retardant aqueous solution) having a maleimide structure at one end and both ends, and the flame-retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure; the tensile strength of the long-lasting flame-retardant polyester monofilament is 9 cN / dtex, the limiting oxygen index is 30.5%, and no dripping is generated during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is 99%; the flexural rigidity of the fabric made of the long-lasting flame-retardant polyester monofilament is 1.2 cN·cm, and the moisture permeability is 5350 g·[m 2 ·(24h)] -1 , thermal resistance performance is 27.5mk·m 2 ·w -1 The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of 91.5% and a K / S value of 26 at a dyeing temperature of 120°C.

Claims

1. A method for preparing a long-lasting flame-retardant polyester monofilament, characterized in that: Firstly, the furan structure-modified polyester and the water-soluble polyester are melt-blended and extruded to obtain modified polyester precursor, and then the modified polyester precursor is placed in a flame retardant solution at 60 to 90° C. for treatment, so that the water-soluble polyester component in the modified polyester precursor is dissolved in the flame retardant solution, and then the treated modified polyester precursor is placed in a flame retardant solution at a temperature of 60 to 98° C. for the first stretching, and finally the modified polyester precursor after the first stretching is post-treated to obtain a long-lasting flame-retardant polyester monofilament; The furan structure-modified polyester is obtained by reacting a mixed dibasic acid with an aliphatic diol, wherein the mixed dibasic acid is prepared by mixing a dibasic acid with furandicarboxylic acid in a molar ratio of 90 to 99:1 to 10. The flame retardant is a phosphorus-containing flame retardant having a maleimide structure at the molecular chain end.

2. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 1, characterized in that: Flame retardant is In the formula, R is a flame retardant structure containing phosphorus elements, and the structural formula is 3. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 1, characterized in that: The solvent of the flame retardant solution is water, and the mass concentration of the flame retardant in the flame retardant solution is 5-20%.

4. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 1, characterized in that: The dibasic acid is one or more of terephthalic acid, isophthalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid; the aliphatic diol is one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol and decanediol; the furandicarboxylic acid is one or more of 2,5-furandicarboxylic acid and 3,4-furandicarboxylic acid.

5. The method for preparing a long-lasting flame-retardant polyester monofilament according to any one of claims 1 to 4, characterized in that: The specific preparation steps of the furan structure-modified polyester are as follows: (1) Esterification reaction: The mixed dibasic acid and the aliphatic diol are mixed and beaten, and then added into an esterification reaction kettle for esterification reaction. The pressure of the esterification reaction is 0.01-0.5 MPa, the reaction temperature is 220-260° C., the reaction time is 0.5-3 h, and the esterification reaction is terminated until the water output reaches 95% of the theoretical water output; wherein the molar ratio of the mixed dibasic acid to the aliphatic diol is 1:1.05-1.10; (2) Pre-polycondensation reaction: Adding a catalyst, an antioxidant and a heat stabilizer to the product of step (1), and carrying out a pre-polycondensation reaction at 250-270° C. and 100-1000 Pa for 15-45 minutes to obtain a pre-polycondensation product with an intrinsic viscosity of ≤0.15 dL / g; wherein the stirring rate of the pre-polycondensation reaction is 5-20 rpm; (3) Final polycondensation reaction: The precondensate obtained in step (2) is subjected to polycondensation reaction at 260-280° C. and 10-100 Pa for 1.5-3.5 hours to obtain a furan structure-containing modified polyester.

6. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 5, characterized in that: The catalyst is one or more of tetrabutyl titanate, ethylene glycol titanium, antimony trioxide, antimony acetate or ethylene glycol antimony; the amount of the catalyst added is 10 to 500 ppm based on the mass of the dibasic acid; The antioxidant is one or more of antioxidant 1010, antioxidant 168 or antioxidant 616; the amount of the antioxidant added is 0.001 to 0.03% of the mass of the dibasic acid; The heat stabilizer is one or more of trimethyl phosphate, alkyl phosphate diester or tris(nonylphenyl)phosphite; the added amount of the heat stabilizer is 0.001-0.02% of the mass of the dibasic acid.

7. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 1, characterized in that: The specific preparation steps of the water-soluble polyester are: (1) mixing terephthalic acid, ethylene glycol, SIPE and a catalyst and performing a first esterification reaction to obtain a first esterification product, wherein the first esterification reaction is performed under a nitrogen atmosphere, at a pressure of 0.01 to 0.5 MPa, at a temperature of 230 to 250° C., and for a time of 0.5 to 2.5 h; (2) mixing the first esterification product and polyethylene glycol and performing a second esterification reaction to obtain a second esterification product, wherein the second esterification reaction is performed at a pressure of 10 to 100 KPa, a temperature of 240 to 255° C., and a time of 0.5 to 2.5 h; (3) subjecting the second esterification product to a pre-polycondensation reaction to obtain a pre-polycondensate, wherein the pre-polycondensation reaction is carried out under a pressure of 100 to 1000 Pa, a temperature of 250 to 260° C., and a time of 0.5 to 1.5 h; (4) subjecting the precondensate to a final polycondensation reaction to obtain a water-soluble polyester melt, wherein the final polycondensation reaction is carried out at a pressure of 150 to 200 Pa, a temperature of 255 to 265° C., and a time of 1.5 to 2 h; (5) Cooling and pelletizing the water-soluble polyester melt to obtain the water-soluble polyester.

8. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 7, characterized in that: In step (1), the molar ratio of terephthalic acid to ethylene glycol is 1:1.1 to 1:1.6; the amount of SIPE added is 10 to 30 wt% of the theoretical mass of the water-soluble polyester; the catalyst is one or more of tetrabutyl titanate, titanium glycol, antimony trioxide, antimony acetate and antimony glycol; during the first esterification reaction, the amount of the catalyst added is 10 to 500 ppm of the mass of terephthalic acid.

9. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 7, characterized in that: The number average molecular weight of the polyethylene glycol in step (2) is 500 to 2500, and the amount of polyethylene glycol added is 10 to 50% of the mass of the first esterification product.

10. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 7, characterized in that: In step (4), the intrinsic viscosity of the water-soluble polyester melt is 0.40 to 0.60 dL / g.

11. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 1, characterized in that: The post-treatment is to perform a second stretching molding on the modified polyester raw yarn after the first stretching at 130°C to 200°C, and then heat-set at 135°C to 210°C, and the heat-setting time is 30s to 2min.

12. The method for preparing a long-lasting flame-retardant polyester monofilament according to claim 11, characterized in that: The stretching multiple of the first stretching is 3 to 5 times; The stretching multiple of the second stretching molding is 1 to 3 times; The relaxation ratio during heat setting is 5% to 25%.

13. A long-lasting flame-retardant polyester monofilament prepared by the method according to any one of claims 1 to 12, characterized in that: It consists of a polyester monofilament and a flame retardant layer distributed on the surface of the polyester monofilament. The polyester monofilament is made of modified polyester containing a furan structure. The surface of the polyester monofilament has a "cavity" structure. The flame retardant layer is made of a phosphorus-containing flame retardant having a maleimide structure at one end and / or both ends. The flame retardant layer is chemically bonded to the furan structure in the polyester monofilament through the maleimide structure.

14. The long-lasting flame-retardant polyester monofilament according to claim 13, characterized in that: The tensile strength of the long-lasting flame-retardant polyester monofilament is 7-9 cN / dtex, the limiting oxygen index is ≥28%, and no dripping is produced during the combustion process; after 30 times of water washing, the limiting oxygen index retention rate of the long-lasting flame-retardant polyester monofilament is more than 95%; The flexural rigidity of the fabric made of long-lasting flame-retardant polyester monofilament is ≤2.0cN·cm, and the moisture permeability is ≥5000g·[m 2 ·(24h)] -1 , thermal resistance performance ≥ 25mk·m 2 ·w -1 ; The fabric made of long-lasting flame-retardant polyester monofilament has a dyeing rate of ≥90% and a K / S value of ≥25 at a dyeing temperature of 120°C.

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