A highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide and its preparation process

Abstract

The invention discloses a highly flame-retardant and environmentally friendly modified PVC material without antimony trioxide and a preparation process thereof, and belongs to the technical field of modified PVC material preparation. The highly flame-retardant and environmentally friendly modified PVC material without antimony trioxide is composed of the following components in parts by weight: 40-60 parts of PVC, 2-8 parts of PVC modifier, 10-15 parts of microcapsule flame retardant, 2-8 parts of tetrahydrofuran, 0.5-2.1 parts of antioxidant, 2-4 parts of coupling agent, wherein the PVC modifier is prepared from diethylene glycol monovinyl ether, propylene acetate, azobisisobutyronitrile, ethyl acetate and methyl tert-butyl ether, and the microcapsule flame retardant is prepared from sodium hydroxide, choline chloride, phytic acid, corn starch, polyethylene glycol, toluene diisocyanate and pentaerythritol. PVC is modified using a PVC modifier, and a microcapsule flame retardant is added at the same time, and the prepared environmentally friendly modified PVC material has excellent flame retardant effect, rheology and toughness.

Description

Technical Field

[0001] The invention belongs to the technical field of modified PVC material preparation, and particularly relates to a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide and a preparation process thereof. Background Art

[0002] With the continuous development of society and technology, PVC materials have been widely used in various fields due to their excellent physical and chemical properties. However, the flammability of PVC materials themselves limits their application in some special fields. Therefore, it is of great significance to develop PVC materials with high flame retardant properties.

[0003] Antimony trioxide is a highly effective additive flame retardant that is widely used to improve the flame retardant properties of PVC materials. However, since the mining and processing of antimony trioxide will cause environmental pollution, and during the combustion process, antimony trioxide will release harmful substances, posing a potential threat to human health and environmental safety, the development of flame retardants that do not contain antimony trioxide has become an urgent need for environmental protection and sustainable development.

[0004] Patent CN 114133680 B discloses a PVC material and a preparation method and use thereof for television or cable. The PVC material comprises the following raw materials: PVC, calcium zinc stabilizer, octyl phthalate, calcium carbonate, stearic acid, antioxidant, acidic lignin, and antimony trioxide. The preparation method of the wire or cable adopts the above materials and comprises the following steps: ball milling acidic lignin and antimony trioxide for 2-12 hours, and the particle size of the mixture of acidic lignin and antimony trioxide after ball milling is 2-8 microns; PVC, the ball milled acidic lignin and antimony trioxide mixture and other components are mixed in proportion to obtain a precursor; the precursor is melt-blended, extruded and granulated to obtain a PVC wire and cable material with high tensile strength, strong resistance to ultraviolet radiation aging and good flame retardancy. However, since antimony trioxide is used as a flame retardant, it will produce substances harmful to the environment during the combustion process. Therefore, it is necessary to provide an environmentally friendly PVC material that does not contain antimony trioxide but still has a high flame retardant effect. Summary of the invention

[0005] The purpose of the present invention is to provide a highly flame-retardant and environmentally friendly modified PVC material without antimony trioxide and a preparation process thereof, so as to solve the technical problems in the prior art that antimony trioxide is often used as a flame retardant, has poor rheological properties, low toughness and poor environmental performance.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention provides a highly flame-retardant and environment-friendly modified PVC material free of antimony trioxide. The material is composed of the following components in parts by weight: 40-60 parts of PVC, 2-8 parts of a PVC modifier, 10-15 parts of a microcapsule flame retardant, 2-8 parts of tetrahydrofuran, 0.5-2.1 parts of an antioxidant, and 2-4 parts of a coupling agent, wherein the PVC modifier is prepared from diethylene glycol monovinyl ether, propylene acetate, azobisisobutyronitrile, ethyl acetate and methyl tert-butyl ether, and the microcapsule flame retardant is prepared from sodium hydroxide, choline chloride, phytic acid, corn starch, polyethylene glycol, toluene diisocyanate and pentaerythritol.

[0008] Preferably, the preparation method of the PVC modifier comprises the following steps:

[0009] Q1: Add diethylene glycol monovinyl ether, propylene acetate, azobisisobutyronitrile and ethyl acetate into a container, seal it, introduce argon gas after freezing and pumping, and react in an oil bath. After the reaction is completed, place the container in an ice bath for rapid cooling and open it to obtain a composite mixture;

[0010] Q2: The composite mixture is slowly added dropwise to methyl tert-butyl ether for precipitation, centrifuged, dissolved, precipitated, and dried to obtain a PVC modifier.

[0011] In the above process, diethylene glycol monovinyl ether and propylene acetate as non-conjugated monomers can undergo free radical copolymerization, and azobisisobutyronitrile is used as an initiator to synthesize the PVC modifier, wherein the copolymerization process is as follows:

[0012]

[0013] Preferably, in Q1, the molar ratio of diethylene glycol monovinyl ether, acrylic acetate, azobisisobutyronitrile and ethyl acetate is (15-23): (21.2-23.6): (0.22-0.68): (49-61), the number of freezing pumping is 3-5 times, the oil bath reaction temperature is 60-70°C, and the oil bath reaction time is 10-12h; in Q2, acetone is used for dissolution, methyl tert-butyl ether is used for precipitation, the drying temperature is 60-70°C, and the drying time is 8-10h.

[0014] Preferably, the method for preparing the microcapsule flame retardant comprises the following steps:

[0015] S1: Sodium hydroxide and choline chloride are dissolved in anhydrous ethanol respectively, and then the ethanol solution of sodium hydroxide is slowly added dropwise to the ethanol solution of choline chloride, stirred, and the precipitate is removed by vacuum filtration to obtain a choline hydroxide solution;

[0016] S2: dissolving phytic acid in anhydrous ethanol, and slowly dropping the phytic acid into the choline hydroxide solution, reacting, rotary evaporating, and vacuum drying to obtain phytate choline; blending phytate choline, corn starch, glycerol, and water, heating for pre-plasticization, melt blending, and pressing to obtain a flame retardant;

[0017] S3: Add polyethylene glycol and 1,4-dioxane to a container, then add toluene diisocyanate, slowly heat up and stir, dissolve pentaerythritol in dimethyl sulfoxide and add to the container, then add flame retardant, 1,4-dioxane, Tween 80 and dibutyltin dilaurate, heat and stir, cool to room temperature, filter, wash, dry and grind to obtain a microcapsule flame retardant.

[0018] In the above process, choline hydroxide solution is prepared by ion exchange, and anhydrous ethanol is used as a green solvent to prepare choline phytate. The preparation process of the microcapsule structure in step S3 is as follows:

[0019]

[0020] Preferably, in S1, the molar ratio of sodium hydroxide to choline chloride is 1:(0.8-1.2), the molar ratio of sodium hydroxide to anhydrous ethanol is 1:(9-9.32), the molar ratio of choline chloride to anhydrous ethanol is 1:(4-4.54), the stirring temperature is 25-28°C, and the stirring time is 1-3h.

[0021] Preferably, in S2, the molar ratio of phytic acid to anhydrous ethanol is 1:(1.5-1.92), the temperature during the dropwise addition is 27-30°C, the reaction time is 1-2h, the vacuum drying temperature is 80-90°C, the time is 20-28h, the mass ratio of phytic acid choline, corn starch, glycerol and water is (10-30):100:30:15, the heating temperature is 80-90°C, the pre-plasticization time is 10-12h, the melt blending temperature is 120-140°C, the time is 5-10min, and the rotation speed is 60-80rpm.

[0022] Preferably, in S3, the molar ratio of polyethylene glycol, toluene diisocyanate and pentaerythritol is 1:(1.8-2.2):(0.1-0.4), the relative molecular mass of polyethylene glycol is 600, the heating temperature is 40-50°C, the stirring time is 0.5-1h, the amount ratio of flame retardant, 1,4-dioxane, Tween 80 and dibutyltin dilaurate is (40-60)g:(90-110)mL:(0.2-0.3)g:(0.1-0.14)g, the heating temperature is 80-90°C, the stirring time is 4-6h, the washing number is 3-5 times, the drying time is 60-70°C, and the drying temperature is 45-50h.

[0023] Preferably, the preparation process of the highly flame-retardant and environmentally friendly modified PVC material without antimony trioxide comprises the following steps:

[0024] Step (1): dissolving the PVC modifier and PVC in tetrahydrofuran, and continuously stirring until the tetrahydrofuran is completely volatilized to obtain modified PVC;

[0025] Step (2): adding modified PVC, microcapsule flame retardant, antioxidant and coupling agent into a high-speed kneader, mixing and stirring to obtain a mixture;

[0026] Step (3): placing the mixture in a twin-screw extruder granulator for extrusion granulation, and drying to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide.

[0027] Preferably, in step (1), the stirring time is 20-24 hours; in step (2), the mixing temperature is 100-120° C., and the mixing time is 5-8 minutes.

[0028] Preferably, in step (3), the temperature in the twin-screw extruder granulator is 120-140°C, the drying temperature is 80-90°C, and the drying time is 8-10h.

[0029] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0030] 1. The present invention first uses diethylene glycol monovinyl ether and propylene acetate to prepare a PVC modifier to modify the PVC material, thereby increasing the toughness and rheological properties of the modified PVC. Subsequently, phytate choline, corn starch and glycerol are used to prepare a flame retardant. Polyethylene glycol and toluene diisocyanate are used to prepare a microcapsule shell, and the flame retardant is wrapped to obtain a microcapsule flame retardant. The microcapsule flame retardant is added to the modified PVC material to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide and has excellent flame retardant effect, rheological properties and toughness.

[0031] 2. The present invention uses diethylene glycol monovinyl ether and propylene acetate as raw materials, synthesizes a PVC modifier under the conditions of azobisisobutyronitrile as an initiator and ethyl acetate as a solvent, and modifies PVC with the PVC modifier to increase the rheological property and toughness of the material. The structure in the PVC modifier can adsorb and entangle with the PVC molecular chain, change the arrangement and movement state of the PVC molecular chain, reduce the friction and resistance between the PVC molecular chains, make it easier to flow in a molten state, and improve the rheological property; at the same time, the addition of the PVC modifier can increase the crosslinking points or chain length in the PVC material, improve the elongation at break and tensile strength of the material, and the formed stable structure can enhance the material's resistance to crack propagation, so that when subjected to external force, it can absorb and disperse part of the energy, reduce the stress concentration phenomenon, delay the generation and propagation of cracks, and thus increase the toughness of the material.

[0032] 3. The present invention adopts ethanol as a green solvent to prepare bio-based phytic choline. Phytic choline and starch constitute a flame retardant. Polyethylene glycol and toluene diisocyanate are reacted to form a microcapsule structure to encapsulate the flame retardant, which is added to the PVC material to effectively increase the flame retardancy of the material. The expansive flame retardant system composed of phytic choline and starch can expand rapidly when the PVC material is heated to form a thick carbonized layer, which can not only effectively isolate oxygen and heat and prevent the further spread of the flame, but also alleviate the heat transfer inside the material and reduce the combustion rate. The presence of the microcapsule flame retardant increases the stability and dispersibility of the flame retardant in the PVC material. When the PVC material encounters fire, the microcapsule gradually breaks and releases the flame retardant component to prevent further erosion of the flame. The phosphorus element in phytic choline can promote the formation of the carbonized layer during the combustion process. The microcapsule flame retardant can provide an additional energy absorption effect to synergistically improve the flame retardancy of the PVC material. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] This embodiment discloses a method for preparing a PVC modifier, comprising the following steps:

[0036] Q1: 2.5 g of diethylene glycol monovinyl ether, 2.24 g of propylene acetate, 0.04 g of azobisisobutyronitrile and 10 g of ethyl acetate were added to a container, which was sealed, frozen and evacuated three times, and then argon was introduced. The reaction was carried out in an oil bath at 60°C for 12 h. After the reaction was completed, the container was placed in an ice bath for rapid cooling and opened to obtain a composite mixture;

[0037] Q2: The composite mixture was slowly added dropwise to methyl tert-butyl ether for precipitation, centrifuged, dissolved with acetone, precipitated with methyl tert-butyl ether, and dried at 70° C. for 8 h to obtain a PVC modifier.

[0038] This embodiment discloses a method for preparing a microcapsule flame retardant, comprising the following steps:

[0039] S1: Dissolve 40 g of sodium hydroxide and 123.6 g of choline chloride in 375 mL and 250 mL of anhydrous ethanol, respectively. Then slowly add the ethanol solution of sodium hydroxide to the ethanol solution of choline chloride, stir at 28° C. for 3 h, and remove the precipitate by vacuum filtration to obtain a choline hydroxide solution.

[0040] S2: 11.39 g of phytic acid was dissolved in 100 mL of anhydrous ethanol, and the mixture was slowly added dropwise to the choline hydroxide solution at 30°C, and the mixture was reacted for 2 h, and the mixture was rotary evaporated and vacuum dried at 90°C for 24 h to obtain phytate choline; 20 g of phytate choline, 100 g of corn starch (75% branched starch and 25% amylose), 30 g of glycerol and 15 g of water were mixed, and the mixture was pre-plasticized at 90°C for 10 h, and melt-blended at 120°C and 80 rpm for 10 min, and pressed to obtain a flame retardant;

[0041] S3: Add 45.45g polyethylene glycol and 20mL 1,4-dioxane to a container, then add 28.11g toluene diisocyanate, slowly heat to 40°C and stir for 1h, dissolve 2.5g pentaerythritol in 20mL dimethyl sulfoxide and add to the container, then add 50g flame retardant, 100mL 1,4-dioxane, 0.25g Tween 80 and 0.12g dibutyltin dilaurate, heat and stir at 90°C for 4h, cool to room temperature, filter, wash 3 times, dry at 70°C for 50h, grind to obtain a microcapsule flame retardant.

[0042] The present embodiment discloses a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, which is composed of the following components in parts by weight: 50 parts of PVC, 5 parts of PVC modifier, 12.5 parts of microcapsule flame retardant, 5 parts of tetrahydrofuran, 1.3 parts of antioxidant 1010, and 3 parts of methylvinyldimethoxysilane.

[0043] This embodiment discloses a preparation process of a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, comprising the following steps:

[0044] Step (1): dissolving the PVC modifier and PVC in tetrahydrofuran, stirring for 24 hours until the tetrahydrofuran is completely evaporated, to obtain modified PVC;

[0045] Step (2): adding modified PVC, microcapsule flame retardant, antioxidant 1010 and methyl vinyl dimethoxy silane into a high-speed kneader, mixing and stirring at 120° C. for 8 minutes to obtain a mixture;

[0046] Step (3): placing the mixture in a twin-screw extruder granulator at 140° C. for extrusion granulation, and drying at 90° C. for 8 h to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide.

[0047] Example 2

[0048] This embodiment discloses a method for preparing a PVC modifier, comprising the following steps:

[0049] Q1: 2 g of diethylene glycol monovinyl ether, 2.12 g of propylene acetate, 0.02 g of azobisisobutyronitrile and 8 g of ethyl acetate were added to a container, which was sealed, frozen and evacuated three times, and then argon was introduced. The reaction was carried out in an oil bath at 60°C for 12 h. After the reaction was completed, the container was placed in an ice bath for rapid cooling and opened to obtain a composite mixture.

[0050] Q2: The composite mixture was slowly added dropwise to methyl tert-butyl ether for precipitation, centrifuged, dissolved with acetone, precipitated with methyl tert-butyl ether, and dried at 70° C. for 8 h to obtain a PVC modifier.

[0051] This embodiment discloses a method for preparing a microcapsule flame retardant, comprising the following steps:

[0052] S1: Dissolve 40 g of sodium hydroxide and 99.2 g of choline chloride in 375 mL and 250 mL of anhydrous ethanol, respectively. Then slowly add the ethanol solution of sodium hydroxide to the ethanol solution of choline chloride, stir at 28 °C for 3 h, and remove the precipitate by vacuum filtration to obtain a choline hydroxide solution.

[0053] S2: 11.39 g of phytic acid was dissolved in 90 mL of anhydrous ethanol, and the mixture was slowly added dropwise to the choline hydroxide solution at 30°C, and the mixture was reacted for 2 h, and the mixture was rotary evaporated and vacuum dried at 90°C for 24 h to obtain phytate choline; 10 g of phytate choline, 100 g of corn starch (75% branched starch and 25% amylose), 30 g of glycerol and 15 g of water were mixed, and the mixture was pre-plasticized at 90°C for 10 h, and melt-blended at 120°C and 80 rpm for 10 min, and pressed to obtain a flame retardant;

[0054] S3: Add 45.45g polyethylene glycol and 20mL 1,4-dioxane to a container, then add 26.23g toluene diisocyanate, slowly heat to 40°C and stir for 1h, dissolve 1g of pentaerythritol in 20mL dimethyl sulfoxide and add to the container, then add 40g flame retardant, 90mL 1,4-dioxane, 0.2g Tween 80 and 0.1g dibutyltin dilaurate, heat and stir at 90°C for 4h, cool to room temperature, filter, wash 3 times, dry at 70°C for 50h, grind to obtain a microcapsule flame retardant.

[0055] The present embodiment discloses a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, which is composed of the following components in parts by weight: 40 parts of PVC, 2 parts of PVC modifier, 10 parts of microcapsule flame retardant, 2 parts of tetrahydrofuran, 0.4 parts of antioxidant 1010, and 2 parts of methylvinyldimethoxysilane.

[0056] This embodiment discloses a preparation process of a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, comprising the following steps:

[0057] Step (1): dissolving the PVC modifier and PVC in tetrahydrofuran, stirring for 24 hours until the tetrahydrofuran is completely evaporated, to obtain modified PVC;

[0058] Step (2): adding modified PVC, microcapsule flame retardant, antioxidant 1010 and methyl vinyl dimethoxy silane into a high-speed kneader, mixing and stirring at 120° C. for 8 minutes to obtain a mixture;

[0059] Step (3): placing the mixture in a twin-screw extruder granulator at 140° C. for extrusion granulation, and drying at 90° C. for 8 h to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide.

[0060] Example 3

[0061] This embodiment discloses a method for preparing a PVC modifier, comprising the following steps:

[0062] Q1: 3 g of diethylene glycol monovinyl ether, 2.36 g of propylene acetate, 0.06 g of azobisisobutyronitrile and 12 g of ethyl acetate were added to a container, which was sealed, frozen and evacuated three times, and then argon was introduced. The reaction was carried out in an oil bath at 60°C for 12 h. After the reaction was completed, the container was placed in an ice bath for rapid cooling and opened to obtain a composite mixture.

[0063] Q2: The composite mixture was slowly added dropwise to methyl tert-butyl ether for precipitation, centrifuged, dissolved with acetone, precipitated with methyl tert-butyl ether, and dried at 70° C. for 8 h to obtain a PVC modifier.

[0064] This embodiment discloses a method for preparing a microcapsule flame retardant, comprising the following steps:

[0065] S1: Dissolve 40 g of sodium hydroxide and 148 g of choline chloride in 375 mL and 250 mL of anhydrous ethanol, respectively, then slowly drop the ethanol solution of sodium hydroxide into the ethanol solution of choline chloride, stir at 28°C for 3 h, remove the precipitate by vacuum filtration, and obtain a choline hydroxide solution;

[0066] S2: 11.39 g of phytic acid was dissolved in 110 mL of anhydrous ethanol, and the mixture was slowly added dropwise to the choline hydroxide solution at 30°C, and the mixture was reacted for 2 h, and then rotary evaporated and vacuum dried at 90°C for 24 h to obtain phytate choline; 30 g of phytate choline, 100 g of corn starch (75% branched starch and 25% amylose), 30 g of glycerol and 15 g of water were mixed, and the mixture was pre-plasticized at 90°C for 10 h, and melt-blended at 120°C and 80 rpm for 10 min, and pressed to obtain a flame retardant;

[0067] S3: Add 45.45g polyethylene glycol and 20mL 1,4-dioxane to a container, then add 31.47g toluene diisocyanate, slowly heat to 40°C and stir for 1h, dissolve 4g pentaerythritol in 20mL dimethyl sulfoxide and add to the container, then add 60g flame retardant, 110mL 1,4-dioxane, 0.3g Tween 80 and 0.14g dibutyltin dilaurate, heat and stir at 90°C for 4h, cool to room temperature, filter, wash 3 times, dry at 70°C for 50h, grind to obtain a microcapsule flame retardant.

[0068] The present embodiment discloses a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, which is composed of the following components in parts by weight: 60 parts of PVC, 8 parts of PVC modifier, 15 parts of microcapsule flame retardant, 8 parts of tetrahydrofuran, 2 parts of antioxidant 1010, and 4 parts of methylvinyldimethoxysilane.

[0069] This embodiment discloses a preparation process of a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, comprising the following steps:

[0070] Step (1): dissolving the PVC modifier and PVC in tetrahydrofuran, stirring for 24 hours until the tetrahydrofuran is completely evaporated, to obtain modified PVC;

[0071] Step (2): adding modified PVC, microcapsule flame retardant, antioxidant 1010 and methyl vinyl dimethoxy silane into a high-speed kneader, mixing and stirring at 120° C. for 8 minutes to obtain a mixture;

[0072] Step (3): placing the mixture in a twin-screw extruder granulator at 140° C. for extrusion granulation, and drying at 90° C. for 8 h to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide.

[0073] Example 4

[0074] This embodiment discloses a method for preparing a PVC modifier, comprising the following steps:

[0075] Q1: 2.2 g of diethylene glycol monovinyl ether, 2.20 g of propylene acetate, 0.03 g of azobisisobutyronitrile and 9 g of ethyl acetate were added to a container, which was sealed, frozen and evacuated three times, and then argon was introduced. The reaction was carried out in an oil bath at 60°C for 12 h. After the reaction was completed, the container was placed in an ice bath for rapid cooling and opened to obtain a composite mixture.

[0076] Q2: The composite mixture was slowly added dropwise to methyl tert-butyl ether for precipitation, centrifuged, dissolved with acetone, precipitated with methyl tert-butyl ether, and dried at 70° C. for 8 h to obtain a PVC modifier.

[0077] This embodiment discloses a method for preparing a microcapsule flame retardant, comprising the following steps:

[0078] S1: Dissolve 40 g of sodium hydroxide and 113.6 g of choline chloride in 375 mL and 250 mL of anhydrous ethanol, respectively, then slowly drop the ethanol solution of sodium hydroxide into the ethanol solution of choline chloride, stir at 28°C for 3 h, remove the precipitate by vacuum filtration, and obtain a choline hydroxide solution;

[0079] S2: 11.39 g of phytic acid was dissolved in 105 mL of anhydrous ethanol, and the mixture was slowly added dropwise to the choline hydroxide solution at 30°C, and the mixture was reacted for 2 h, and the mixture was rotary evaporated and vacuum dried at 90°C for 24 h to obtain phytate choline; 25 g of phytate choline, 100 g of corn starch (75% branched starch and 25% amylose), 30 g of glycerol and 15 g of water were mixed, and the mixture was pre-plasticized at 90°C for 10 h, and melt-blended at 120°C and 80 rpm for 10 min, and pressed to obtain a flame retardant;

[0080] S3: Add 45.45g polyethylene glycol and 20mL 1,4-dioxane to a container, then add 20.78g toluene diisocyanate, slowly heat to 40°C and stir for 1h, dissolve 2g of pentaerythritol in 20mL dimethyl sulfoxide and add to the container, then add 45g flame retardant, 105mL 1,4-dioxane, 0.27g Tween 80 and 0.11g dibutyltin dilaurate, heat and stir at 90°C for 4h, cool to room temperature, filter, wash 3 times, dry at 70°C for 50h, grind to obtain a microcapsule flame retardant.

[0081] The present embodiment discloses a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, which is composed of the following components in parts by weight: 45 parts of PVC, 3 parts of PVC modifier, 11 parts of microcapsule flame retardant, 7 parts of tetrahydrofuran, 1.5 parts of antioxidant 1010, and 2.5 parts of methylvinyldimethoxysilane.

[0082] This embodiment discloses a preparation process of a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, comprising the following steps:

[0083] Step (1): dissolving the PVC modifier and PVC in tetrahydrofuran, stirring for 24 hours until the tetrahydrofuran is completely evaporated, to obtain modified PVC;

[0084] Step (2): adding modified PVC, microcapsule flame retardant, antioxidant 1010 and methyl vinyl dimethoxy silane into a high-speed kneader, mixing and stirring at 120° C. for 8 minutes to obtain a mixture;

[0085] Step (3): placing the mixture in a twin-screw extruder granulator at 140° C. for extrusion granulation, and drying at 90° C. for 8 h to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide.

[0086] Example 5

[0087] This embodiment discloses a method for preparing a PVC modifier, comprising the following steps:

[0088] Q1: 2.7 g of diethylene glycol monovinyl ether, 2.30 g of propylene acetate, 0.05 g of azobisisobutyronitrile and 11 g of ethyl acetate were added to a container, which was sealed, frozen and evacuated three times, and then argon was introduced. The reaction was carried out in an oil bath at 60°C for 12 h. After the reaction was completed, the container was placed in an ice bath for rapid cooling and opened to obtain a composite mixture;

[0089] Q2: The composite mixture was slowly added dropwise to methyl tert-butyl ether for precipitation, centrifuged, dissolved with acetone, precipitated with methyl tert-butyl ether, and dried at 70° C. for 8 h to obtain a PVC modifier.

[0090] This embodiment discloses a method for preparing a microcapsule flame retardant, comprising the following steps:

[0091] S1: Dissolve 40 g of sodium hydroxide and 130 g of choline chloride in 375 mL and 250 mL of anhydrous ethanol, respectively, then slowly add the ethanol solution of sodium hydroxide to the ethanol solution of choline chloride, stir at 28°C for 3 h, remove the precipitate by vacuum filtration, and obtain a choline hydroxide solution;

[0092] S2: 11.39 g of phytic acid was dissolved in 95 mL of anhydrous ethanol, and the mixture was slowly added dropwise to the choline hydroxide solution at 30°C, and the mixture was reacted for 2 h, and the mixture was rotary evaporated and vacuum dried at 90°C for 24 h to obtain phytate choline; 15 g of phytate choline, 100 g of corn starch (75% branched starch and 25% amylose), 30 g of glycerol and 15 g of water were mixed, and the mixture was pre-plasticized at 90°C for 10 h, and melt-blended at 120°C and 80 rpm for 10 min, and pressed to obtain a flame retardant;

[0093] S3: Add 45.45g polyethylene glycol and 20mL 1,4-dioxane to a container, then add 27.15g toluene diisocyanate, slowly heat to 40°C and stir for 1h, dissolve 3g of pentaerythritol in 20mL dimethyl sulfoxide and add to the container, then add 55g flame retardant, 95mL 1,4-dioxane, 0.21g Tween 80 and 0.13g dibutyltin dilaurate, heat and stir at 90°C for 4h, cool to room temperature, filter, wash 3 times, dry at 70°C for 50h, grind to obtain a microcapsule flame retardant.

[0094] The present embodiment discloses a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, which is composed of the following components in parts by weight: 55 parts of PVC, 7 parts of PVC modifier, 13 parts of microcapsule flame retardant, 3 parts of tetrahydrofuran, 0.8 parts of antioxidant 1010, and 3.5 parts of methylvinyldimethoxysilane.

[0095] This embodiment discloses a preparation process of a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, comprising the following steps:

[0096] Step (1): dissolving the PVC modifier and PVC in tetrahydrofuran, stirring for 24 hours until the tetrahydrofuran is completely evaporated, to obtain modified PVC;

[0097] Step (2): adding modified PVC, microcapsule flame retardant, antioxidant 1010 and methyl vinyl dimethoxy silane into a high-speed kneader, mixing and stirring at 120° C. for 8 minutes to obtain a mixture;

[0098] Step (3): placing the mixture in a twin-screw extruder granulator at 140° C. for extrusion granulation, and drying at 90° C. for 8 h to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide.

[0099] Comparative Example 1

[0100] Comparative Example 1 Compared with Example 1, in the process of preparing the PVC modifier in Comparative Example 1, diethylene glycol monovinyl ether was not added, and other conditions remained unchanged.

[0101] Comparative Example 2

[0102] Comparative Example 2 Compared with Example 1, in the process of preparing the PVC modifier in Comparative Example 2, no propylene acetate was added, and other conditions remained unchanged.

[0103] Comparative Example 3

[0104] Comparative Example 3 Compared with Example 1, in the process of preparing the microcapsule flame retardant in Comparative Example 3, phytic acid is not added, and other conditions remain unchanged.

[0105] Comparative Example 4

[0106] Comparative Example 4 Compared with Example 1, in the process of preparing the microcapsule flame retardant in Comparative Example 4, no polyethylene glycol was added, and other conditions remained unchanged.

[0107] Comparative Example 5

[0108] Comparative Example 5 Compared with Example 1, in the process of preparing the microcapsule flame retardant in Comparative Example 5, toluene diisocyanate is not added, and other conditions remain unchanged.

[0109] Comparative Example 6

[0110] Comparative Example 6 Compared with Example 1, in the process of preparing the highly flame-retardant and environmentally friendly modified PVC material without antimony trioxide in Comparative Example 5, no PVC modifier is added, and other conditions remain unchanged.

[0111] Comparative Example 7

[0112] Comparative Example 7 Compared with Example 1, in the process of preparing the highly flame-retardant and environmentally friendly modified PVC material without antimony trioxide in Comparative Example 7, no microcapsule flame retardant is added, and other conditions remain unchanged.

[0113] The performance of the highly flame-retardant and environmentally friendly modified PVC materials without antimony trioxide prepared in Examples 1-5 and Comparative Examples 1-7 was tested. The flame retardant properties of the samples were tested according to the "UL94 Flame Retardant Test Method and Standard", the rheological properties of the samples were measured according to ASTM D 1238, and the toughness of the samples was tested according to GB / T 41932-2022. The test results are shown in Table 1:

[0114] Table 1

[0115]

[0116]

[0117] It can be seen from the test results in Table 1 that the highly flame-retardant and environmentally friendly modified PVC material without antimony trioxide prepared in Examples 1-5 of the present invention has excellent flame retardant effect, rheological properties and toughness. By comparing Comparative Example 1 with Examples 1-5, it can be seen that the addition of diethylene glycol monovinyl ether can effectively improve the rheological properties and toughness of PVC materials; by comparing Comparative Example 2 with Examples 1-5, it can be seen that the addition of propylene acetate can effectively improve the rheological properties and toughness of PVC materials; by comparing Comparative Example 3 with Examples 1-5, it can be seen that the addition of phytic acid can effectively improve the flame retardant properties of PVC materials; by comparing Comparative Example 4 with Examples 1-5, it can be seen that the addition of polyethylene glycol can effectively improve the flame retardant properties of PVC materials; by comparing Comparative Example 5 with Examples 1-5, it can be seen that the addition of toluene diisocyanate can effectively improve the flame retardant properties of PVC materials; by comparing Comparative Example 6 with Examples 1-5, it can be seen that the addition of PVC modifier can effectively improve the rheological properties and toughness of PVC materials; by comparing Comparative Example 7 with Examples 1-5, it can be seen that the addition of microcapsule flame retardant can effectively improve the flame retardant properties of PVC materials.

[0118] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0119] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide, characterized in that: The invention is composed of the following components in parts by weight: 40-60 parts of PVC, 2-8 parts of PVC modifier, 10-15 parts of microcapsule flame retardant, 2-8 parts of tetrahydrofuran, 0.5-2.1 parts of antioxidant, and 2-4 parts of coupling agent, wherein the PVC modifier is prepared from diethylene glycol monovinyl ether, propylene acetate, azobisisobutyronitrile, ethyl acetate and methyl tert-butyl ether, and the microcapsule flame retardant is prepared from sodium hydroxide, choline chloride, phytic acid, corn starch, polyethylene glycol, toluene diisocyanate and pentaerythrital. The preparation method of the PVC modifier comprises the following steps: Q1: Add diethylene glycol monovinyl ether, propylene acetate, azobisisobutyronitrile and ethyl acetate into a container, seal it, introduce argon after freezing and pumping, react in an oil bath, and after the reaction is completed, place the container in an ice bath for rapid cooling and open it to obtain a composite mixture; the molar ratio of diethylene glycol monovinyl ether, propylene acetate, azobisisobutyronitrile and ethyl acetate is (15-23): (21.2-23.6): (0.22-0.68): (49-61); Q2: adding the composite mixture dropwise into methyl tert-butyl ether for precipitation, centrifugation, dissolution, precipitation, and drying to obtain a PVC modifier; The preparation method of the microcapsule flame retardant comprises the following steps: S1: Sodium hydroxide and choline chloride are dissolved in anhydrous ethanol respectively, and then the ethanol solution of sodium hydroxide is added dropwise to the ethanol solution of choline chloride, stirred, and the precipitate is removed by vacuum filtration to obtain a choline hydroxide solution; S2: dissolving phytic acid in anhydrous ethanol, and adding the phytic acid to a choline hydroxide solution, reacting, rotary evaporating, and vacuum drying to obtain phytate choline; blending phytate choline, corn starch, glycerol, and water, heating for pre-plasticization, melt blending, and pressing to obtain a flame retardant; S3: Add polyethylene glycol and 1,4-dioxane to a container, then add toluene diisocyanate, heat and stir, dissolve pentaerythritol in dimethyl sulfoxide and add to the container, then add flame retardant, 1,4-dioxane, Tween 80 and dibutyltin dilaurate, heat and stir, cool to room temperature, filter, wash, dry and grind to obtain a microcapsule flame retardant; the molar ratio of polyethylene glycol, toluene diisocyanate and pentaerythritol is 1: (1.8-2.2): (0.1-0.4).

2. The highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide according to claim 1, characterized in that: In Q1, the number of freezing pumping is 3-5 times, the oil bath reaction temperature is 60-70°C, and the oil bath reaction time is 10-12h; in Q2, acetone is used for dissolution, methyl tert-butyl ether is used for precipitation, the drying temperature is 60-70°C, and the drying time is 8-10h.

3. The highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide according to claim 1, characterized in that: In the S1, the molar ratio of sodium hydroxide to choline chloride is 1:(0.8-1.2), the molar ratio of sodium hydroxide to anhydrous ethanol is 1:(9-9.32), the molar ratio of choline chloride to anhydrous ethanol is 1:(4-4.54), the stirring temperature is 25-28°C, and the stirring time is 1-3h.

4. The highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide according to claim 1, characterized in that: In the S2, the molar ratio of phytic acid to anhydrous ethanol is 1:(1.5-1.92), the temperature during the dropwise addition is 27-30°C, the reaction time is 1-2h, the vacuum drying temperature is 80-90°C, the time is 20-28h, the mass ratio of phytic acid choline, corn starch, glycerol and water is (10-30):100:30:15, the heating temperature is 80-90°C, the pre-plasticization time is 10-12h, the melt blending temperature is 120-140°C, the time is 5-10min, and the rotation speed is 60-80rpm.

5. The highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide according to claim 1, characterized in that: In the S3, the relative molecular mass of polyethylene glycol is 600, the heating temperature is 40-50°C, the stirring time is 0.5-1h, the dosage ratio of flame retardant, 1,4-dioxane, Tween 80 and dibutyltin dilaurate is (40-60) g: (90-110) mL: (0.2-0.3) g: (0.1-0.14) g, the heating temperature is 80-90°C, the stirring time is 4-6h, the washing number is 3-5 times, the drying time is 60-70°C, and the drying temperature is 45-50h.

6. A process for preparing a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: Step (1): dissolving the PVC modifier and PVC in tetrahydrofuran, and continuously stirring until the tetrahydrofuran is completely volatilized to obtain modified PVC; Step (2): adding modified PVC, microcapsule flame retardant, antioxidant and coupling agent into a high-speed kneader, and mixing and stirring to obtain a mixture; Step (3): placing the mixture in a twin-screw extruder granulator for extrusion granulation, and drying to obtain a highly flame-retardant and environmentally friendly modified PVC material that does not contain antimony trioxide.

7. The process for preparing a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide according to claim 6, characterized in that: In the step (1), the stirring time is 20-24 hours; in the step (2), the mixing temperature is 100-120° C., and the mixing time is 5-8 minutes.

8. The process for preparing a highly flame-retardant and environmentally friendly modified PVC material free of antimony trioxide according to claim 6, characterized in that: In the step (3), the temperature in the twin-screw extruder granulator is 120-140°C, the drying temperature is 80-90°C, and the drying time is 8-10 hours.

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