Blended halogen-free composite flame-retardant polyester master batch and preparation method thereof

Abstract

The invention relates to the technical field of flame-retardant polyester, and discloses a blended halogen-free composite flame-retardant polyester master batch and a preparation method thereof.The polyester master batch is prepared from 60-80 parts of PET polyester, 0.5-1 part of a fatty acid amide dispersing agent, 1-2 parts of a nano inorganic stabilizer and 15-50 parts of a flame retardant, and the flame retardant comprises phytic acid and chitosan; according to the polyester master batch, the fatty acid amide dispersing agent and the inorganic stabilizer are added, so that the dispersity and the thermal stability of phytic acid and chitosan in PET polyester are remarkably improved, the spinnability, the flame retardant property and the washing resistance of the polyester master batch are remarkably improved, and LOI can reach 32% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of flame-retardant polyester, in particular to a blended halogen-free composite flame-retardant polyester masterbatch and a preparation method thereof. Background Art

[0002] Polyester materials are widely used in textiles, with polyethylene terephthalate (PET) dominating the textile polyester market due to its excellent mechanical and thermal properties. However, pure PET is highly flammable, and fabrics made from it are highly flammable, potentially causing fires. To address this flammability issue, researchers in the field have proposed modifying pure PET with flame retardants to impart flame retardancy.

[0003] There are many types of flame retardants for polyester that have been disclosed so far, among which halogen-containing flame retardants are the most widely used flame retardants. However, halogen-containing flame retardants will generate persistent organic pollutants (POPs) during the combustion process. These pollutants are not easy to degrade and exist in the environment for a long time. Once they enter the ecosystem, they will accumulate through the food chain and are highly destructive to the ecological environment. In recent years, in response to the concept of green environmental protection, those skilled in the art have disclosed green flame retardants, such as phosphorus-based flame retardants, nitrogen-based flame retardants, inorganic flame retardants, etc. The raw materials of green flame retardants are mainly bio-based materials. Bio-based materials have high carbon-forming properties and can form a stable carbon layer on the surface of polyester materials. In addition, in order to improve the performance of flame retardants, different types of flame retardants are usually compounded in the existing technology. The combination of different types of flame retardants can play a synergistic role, thereby further improving the flame retardant properties of polyester.

[0004] Phytic acid and chitosan are bio-based flame retardants that have been widely studied in recent years. Phytic acid and chitosan are compounded and used with excellent flame retardant effect. For example, in publication number CN114752096B, phytic acid and chitosan are used as flame retardant source epoxy waste grease as a cross-linking agent to form a flame retardant layer on the surface of polyester fabric, which increases the flame retardancy and washability of the fabric, and has no significant change in the physical properties of the fabric. For another example, in publication number CN114539623B, phytic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide and chitosan microspheres are reacted to form a flame retardant that integrates an acid source, a carbon source and a synergist. When it is used for the flame retardant modification of polyurethane materials, the mechanical properties of the polyurethane materials do not change significantly. When phytic acid and chitosan are applied to PET polyester in the present invention, it is found that the dispersibility of phytic acid and chitosan in the PET polyester material is poor, resulting in reduced spinnability of the modified PET polyester material. In addition, phytic acid and chitosan have poor thermal stability, resulting in no significant improvement in the flame retardancy of PET polyester. Summary of the Invention

[0005] The present invention addresses the problems of poor dispersibility and poor thermal stability in flame-retardant modification of PET polyester using phytic acid and chitosan in the prior art, and provides a blended halogen-free composite flame-retardant polyester masterbatch and a preparation method thereof. The polyester masterbatch significantly improves the dispersibility and thermal stability of phytic acid and chitosan in PET polyester by adding a fatty acid amide dispersant and an inorganic stabilizer, thereby significantly improving the spinnability, flame retardancy and water-washing resistance of the polyester masterbatch.

[0006] The specific technical solutions of the present invention are: A blended halogen-free composite flame-retardant polyester masterbatch comprises, by weight, 60-80 parts of PET polyester, 0.5-1 part of a fatty acid amide dispersant, 1-2 parts of a nano inorganic stabilizer, and 15-50 parts of a flame retardant; the flame retardant comprises phytic acid and chitosan.

[0007] Preferably, the mass ratio of phytic acid to chitosan is 1:1-5.

[0008] Preferably, the intrinsic viscosity of the blended halogen-free composite flame-retardant polyester masterbatch is 0.49 to 0.56 dL / g.

[0009] Preferably, the nano inorganic stabilizer is nano montmorillonite.

[0010] The present invention provides a blended halogen-free composite flame-retardant polyester masterbatch, wherein the flame retardants in the polyester masterbatch are phytic acid and chitosan. The polyester masterbatch has high spinnability, excellent flame retardancy, and strong water washability. The present invention has discovered that when phytic acid and chitosan are used to flame-retardantly modify PET polyester, the phytic acid and chitosan suffer from poor dispersibility, resulting in a significant increase in the pressure filtration value of the polyester material and a significant decrease in the spinnability of the polyester material. Furthermore, the phytic acid and chitosan-modified PET polyester has poor thermal oxidative decomposition performance when forming char after combustion, failing to form a stable carbon layer, and thus not significantly improving the flame retardancy of the PET polyester. Therefore, to address these two issues, the present invention significantly improves the dispersibility of phytic acid and chitosan in the polyester material by adding a fatty acid amide dispersant, significantly reducing the pressure filtration value of the modified polyester and significantly improving the spinnability of the modified polyester. The present invention also significantly improves the thermal oxidative stability of the char formed by combustion of phytic acid and chitosan by adding a nano-inorganic stabilizer, promoting the formation of an effective carbon layer and significantly improving the flame retardancy of the flame-retardant polyester. In addition, the fabric made from the modified polyester masterbatch also has excellent washability.

[0011] The present invention also found that the ratio of phytic acid to chitosan has an important influence on the flame retardancy of PET polyester, and the ratio of phytic acid to chitosan must reach a certain ratio to enable PET polyester to obtain significant flame retardancy.

[0012] A method for preparing the above-mentioned blended halogen-free composite flame-retardant polyester masterbatch comprises the following steps: pre-dispersing PET polyester, flame retardant, fatty acid amide dispersant, nano inorganic stabilizer and flame retardant; injecting the pre-dispersed materials into a mixing and extrusion device for mixing, extrusion, cooling and pelletizing to prepare the blended halogen-free composite flame-retardant polyester masterbatch.

[0013] Preferably, the temperatures of the zones of the mixing and extruding device include: zone one temperature 200-240°C, zone two temperature 200-240°C, zone three temperature 240-260°C, zone four temperature 240-260°C, zone five temperature 250-265°C, zone six temperature 240-260°C, zone seven temperature 250-260°C, and the die head temperature is 250-260°C.

[0014] Preferably, the rotation speed of the mixing and extruding device is 150-180 rpm, and the main feeding frequency is 10-20 Hz.

[0015] Preferably, the pre-dispersion speed is 500-1000 rpm, and the pre-dispersion time is 3-8 minutes.

[0016] Preferably, the high molecular weight polyester is dried before being pre-dispersed, with a drying temperature of 110 to 120° C. and a drying time of 10 to 24 hours.

[0017] Preferably, the flame retardant is dried before being pre-dispersed, with a drying temperature of 50 to 60° C. and a drying time of 10 to 20 hours.

[0018] Compared with the existing technology, this application has the following technical effects: (1) The present invention uses phytic acid and chitosan to compound as flame retardants for PET polyester. Phytic acid and chitosan are both derived from natural substances, are non-toxic and harmless, and have little pollution to the environment, which is in line with the current development concept of green environmental protection.

[0019] (2) The present invention increases the dispersibility of phytic acid and chitosan in PET polyester by adding fatty acid amide dispersant, significantly reduces the pressure filtration value of flame retardant polyester, improves the spinnability of flame retardant polyester, and the prepared fiber has a breaking strength of up to 3.5 cN / dtex and an elongation at break of up to 20%.

[0020] (3) The present invention significantly improves the thermal oxidation stability of phytic acid and chitosan after combustion into carbon by adding nano-inorganic stabilizers, promotes the formation of an effective carbon layer, and significantly improves the flame retardant properties of flame-retardant polyester, with LOI reaching more than 32%; in addition, the amount of flame retardant used in the present invention is small, and the living cost of polyester is low.

[0021] (4) The flame retardant used in the present invention is not easy to fall off in the polyester masterbatch, and the textiles made from the polyester masterbatch have excellent water washability. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the embodiments.

[0023] Example 1: A method for preparing a blended halogen-free composite flame-retardant polyester masterbatch comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) The above 62 parts of PET polyester chips, 15 parts of phytic acid, 15 parts of chitosan, 2 parts of nano-montmorillonite (particle size 400 nm, Jiangsu Lianrui New Materials Co., Ltd.) and 1 part of fatty acid amide dispersant (TAF, Suzhou Xingtai Guoguang Chemical Additive Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 minutes to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:1; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0024] Example 2: A method for preparing a blended halogen-free composite flame-retardant polyester masterbatch comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) The above 67 parts of PET polyester chips, 10 parts of phytic acid, 20 parts of chitosan, 2 parts of nano-montmorillonite (particle size 400 nm, Jiangsu Lianrui New Materials Co., Ltd.) and 1 part of fatty acid amide dispersant (TAF, Suzhou Xingtai Guoguang Chemical Additive Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 minutes to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:2; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0025] Example 3: A method for preparing a blended halogen-free composite flame-retardant polyester masterbatch comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) The above 67 parts of PET polyester chips, 7.5 parts of phytic acid, 22.5 parts of chitosan, 2 parts of nano-montmorillonite (particle size 400 nm, Jiangsu Lianrui New Materials Co., Ltd.) and 1 part of fatty acid amide dispersant (TAF, Suzhou Xingtai Guoguang Chemical Additive Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 minutes to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:3; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0026] Example 4: A method for preparing a blended halogen-free composite flame-retardant polyester masterbatch comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) The above 62 parts of PET polyester chips, 6 parts of phytic acid, 24 parts of chitosan, 2 parts of nano-montmorillonite (particle size 400 nm, Jiangsu Lianrui New Materials Co., Ltd.) and 1 part of fatty acid amide dispersant (TAF, Suzhou Xingtai Guoguang Chemical Additive Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 minutes to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:4; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0027] Example 5: A method for preparing a blended halogen-free composite flame-retardant polyester masterbatch comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) The above 62 parts of PET polyester chips, 5 parts of phytic acid, 25 parts of chitosan, 2 parts of nano-montmorillonite (particle size 400 nm, Jiangsu Lianrui New Materials Co., Ltd.) and 1 part of fatty acid amide dispersant (TAF, Suzhou Xingtai Guoguang Chemical Additive Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 minutes to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:5; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0028] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the raw materials of Comparative Example 1 are PET polyester, phytic acid and chitosan; and the process comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) injecting the above 62 parts of PET polyester chips, 15 parts of phytic acid and 15 parts of chitosan into a high-speed mixer and stirring and mixing at a speed of 1000 rpm for 5 minutes to prepare a pre-dispersed material, wherein the mass ratio of phytic acid to chitosan is 1:1; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0029] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the raw materials of Comparative Example 2 are PET polyester, phytic acid, chitosan and nano-montmorillonite; and the process comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) 62 parts of PET polyester chips, 15 parts of phytic acid, 15 parts of chitosan, and 2 parts of nano-montmorillonite (particle size 400 nm, Jiangsu Lianrui New Materials Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 min to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:1. (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0030] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the raw material of Comparative Example 3 is PET polyester, and the following steps are included: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h; (2) injecting the above PET polyester chips into a high-speed mixer and stirring at 1000 rpm for 5 minutes to prepare a pre-dispersed material; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0031] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that the raw materials of Comparative Example 4 are PET polyester, fatty acid amide dispersant and nano-montmorillonite, and the following steps are included: (1) PET polyester chips (with an intrinsic viscosity of 0.65 dL / g) are dried at 120° C. for 24 h; (2) 62 parts of the above-mentioned PET polyester chips, 2 parts of nano-montmorillonite (particle size 400 nm, Jiangsu Lianrui New Materials Co., Ltd.) and 1 part of fatty acid amide dispersant (TAF, Suzhou Xingtai Guoguang Chemical Additive Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 min to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:1; (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0032] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that the raw materials of Comparative Example 5 are PET polyester, phytic acid, chitosan and fatty acid amide dispersant, and the process comprises the following steps: (1) PET polyester chips (intrinsic viscosity 0.65 dL / g) were dried at 120°C for 24 h, and phytic acid and chitosan were dried at 60°C for 24 h; (2) 62 parts of the above-mentioned PET polyester chips, 15 parts of phytic acid, 15 parts of chitosan and 1 part of fatty acid amide dispersant (TAF, Suzhou Xingtai Guoguang Chemical Additive Co., Ltd.) were injected into a high-speed blender and stirred at 1000 rpm for 5 minutes to prepare a pre-dispersed material. The mass ratio of phytic acid to chitosan was 1:1. (3) The pre-dispersed material is injected into the vibrating feed port of the mixer extrusion device (Nanjing Ruiya Extrusion Machinery Manufacturing Co., Ltd. TSE-20 / 600-5.5-48, the temperature of each zone is: zone 1 temperature 230℃, zone 2 temperature 235℃, zone 3 temperature 250℃, zone 4 temperature 255℃, zone 5 temperature 260℃, zone 6 temperature 260℃, zone 7 temperature 255℃, head temperature is 250℃, main engine speed is 190rpm, main feed port frequency is 20Hz) for melt mixing. The extruded melt has a water flow length of 160cm in the water tank, is dried and shaped in a blow dryer, and then enters the pelletizer to form a blended halogen-free composite flame retardant polyester masterbatch.

[0033] Test Example 1: The flame retardant polyester masterbatch prepared in Examples 1 to 5 and Comparative Examples 1 to 5 was tested, and the test items included: pressure filtration value, intrinsic viscosity, residual carbon content, limiting oxygen index and vertical burning grade; The pressure filtration value is tested using a pressure filter tester; The residual carbon content is tested according to the gravimetric method; The viscosity of the special new product is tested according to the method disclosed in "GB / T14190-2017 Test method for fiber-grade polyester (PET) chips 5.1.1 Capillary viscometer method"; The flame retardant polyester masterbatch was prepared into combustion samples to test the residual carbon content, limiting oxygen index and water washability. The sample preparation method comprises the following steps: injecting the flame retardant masterbatch and PET chips into a high-speed blender at a mass ratio of 6:94 and mixing them evenly, and then injecting the mixed sample into a precision micro-injection molding machine TY-7003 to prepare the sample; The limiting oxygen index was sampled and tested according to the method disclosed in 7.1 of GBT 2406.2-2009 Determination of Combustion Behavior by Oxygen Index Method for Plastics. The test device was the JF-5 oxygen index tester from Nanjing Jionglei Instrument Equipment Co., Ltd. Washability: The limiting oxygen index test is conducted according to the method disclosed in GB / 20286-2006 Flame retardant products and components for public places - Combustion performance requirements and labeling. Before the combustion test, the washable combustion-supporting materials are washed according to the washing procedures specified in GB / T17596-1998 "Commercial washing procedures for textile fabrics before combustion tests"; The test results are shown in Table 1. Table 1 Test results As shown in Table 1, the flame retardant polyester masterbatch prepared in Examples 1 to 5 has a pressure filtration value of 0.24-0.65 MPa, an intrinsic viscosity of 0.49-0.56 dL / g, a carbon residue after combustion of 22.9-24.9%, a limiting oxygen index of 28-33%, a vertical combustion grade of V-0, and no significant change in flame retardancy after 12 water washings. The above results indicate that the flame retardant polyester masterbatch provided by the present invention has excellent spinnability, excellent flame retardant properties, belongs to a flame retardant material, and has good water washing resistance.

[0034] In addition, it can be seen from the results of Examples 1 to 5 that the usage ratio of phytic acid and chitosan has an important influence on the flame retardancy of the flame retardant polyester. When the mass ratio of phytic acid and chitosan is 1:1 to 2, the flame retardancy of the flame retardant polyester is significantly increased compared with that of pure PET polyester. When the mass ratio of phytic acid and chitosan is 1:3 to 5, the flame retardant performance of the flame retardant polyester is higher than that of pure PET polyester, but the increase in flame retardancy is not significant.

[0035] Compared with Example 1, Comparative Example 1 and Comparative Example 2 were not added with dispersant and stabilizer in Comparative Example 1, and no dispersant was added in Comparative Example 2. The results showed that the pressure filtration value of the flame-retardant polyester in Comparative Example 1 reached 4.68 MPa, and the pressure filtration value of the flame-retardant polyester in Comparative Example 2 reached 4.36 MPa. The results show that the pressure filtration value of the flame-retardant polyester prepared by modifying PET polyester with phytic acid and chitosan will be significantly increased, and the spinnability of the flame-retardant polyester is low. However, the pressure filtration value of the flame-retardant polyester after adding the fatty acid amide dispersant by the present invention is significantly reduced to a level with excellent spinnability.

[0036] Compared with Example 1, Comparative Example 3 and Comparative Example 4 are pure PET polyester, and no phytic acid and chitosan are added to Comparative Example 4. The results show that the pressure filtration value of Comparative Example 4 reaches 3.54 MPa, the residual carbon content of Comparative Example 3 is 4.8%, the residual carbon content of Comparative Example 4 is 3.9%, the limiting oxygen index of Comparative Example 3 is 27%, and the limiting oxygen index of Comparative Example 4 is 28%. It can be seen from the above results that only adding nano-montmorillonite will significantly increase the pressure filtration value of flame-retardant polyester. Adding phytic acid and chitosan on the basis of adding nano-montmorillonite will further increase the pressure filtration value of flame-retardant polyester and reduce the spinnability of flame-retardant polyester. In addition, only adding nano-montmorillonite is not helpful for the combustion charring of PET polyester, and there is also a phenomenon of reduced charring, but only adding nano-montmorillonite has a promoting effect on improving the limiting oxygen index of PPET polyester.

[0037] Compared with Example 1, Comparative Example 5 does not add nano-montmorillonite. The results show that the residual carbon amount of Comparative Example 5 is equivalent to that of Example 1, and the limiting oxygen index is significantly lower than that of Example 1. After in-depth analysis, it is found that nano-montmorillonite has an effect on the thermal oxidation stability after combustion into carbon, can promote the thermal stability after combustion into carbon, ensure the effective stability of the carbon layer, thereby significantly increasing the limiting oxygen index of the flame retardant polyester.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A blended halogen-free composite flame-retardant polyester masterbatch, characterized in that: The raw materials include 60-80 parts of PET polyester, 0.5-1 part of fatty acid amide dispersant, 1-2 parts of nano inorganic stabilizer and 15-50 parts of flame retardant in terms of mass ratio; the flame retardant includes phytic acid and chitosan.

2. The blended halogen-free composite flame-retardant polyester masterbatch according to claim 1, characterized in that: The mass ratio of phytic acid to chitosan is 1:1~5.

3. The blended halogen-free composite flame-retardant polyester masterbatch according to claim 1, characterized in that: The intrinsic viscosity of the blended halogen-free composite flame-retardant polyester masterbatch is 0.49~0.56 dL / g.

4. The blended halogen-free composite flame-retardant polyester masterbatch according to claim 1, characterized in that: The nano inorganic stabilizer is nano montmorillonite.

5. A method for preparing the blended halogen-free composite flame-retardant polyester masterbatch according to any one of claims 1 to 4, characterized in that: The following steps are involved: The high molecular weight polyester, flame retardant, fatty acid amide dispersant, nano inorganic stabilizer and flame retardant are pre-dispersed, and the pre-dispersed materials are injected into a mixing and extruding device for mixing, extrusion, cooling and pelletizing to prepare a blended halogen-free composite flame retardant polyester masterbatch.

6. The preparation method according to claim 5, characterized in that: The temperatures of the various zones of the mixing and extruding device include: zone one temperature of 200-240°C, zone two temperature of 200-240°C, zone three temperature of 240-260°C, zone four temperature of 240-260°C, zone five temperature of 250-265°C, zone six temperature of 240-260°C, zone seven temperature of 250-260°C, and the die head temperature of 250-260°C.

7. The preparation method according to claim 5 or 6, characterized in that: The rotation speed of the mixing and extruding device is 150-180 rpm, and the main feeding frequency is 10-20 Hz.

8. The preparation method according to claim 5, characterized in that: The pre-dispersion speed is 500-1000 rpm, and the pre-dispersion time is 3-8 min.

9. The preparation method according to claim 5, characterized in that: The high molecular weight polyester is dried before pre-dispersion, with a drying temperature of 110-120°C and a drying time of 10-24 h.

10. The preparation method according to claim 5, characterized in that: The flame retardant is dried before pre-dispersion, with a drying temperature of 50~60℃ and a drying time of 10~20 hours.

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