WO2020224182A1

WO2020224182A1 - Environment-friendly flame-retardant plastic master batch capable of preventing from blooming and precipitation and preparation method therefor

Info

Publication number: WO2020224182A1
Application number: PCT/CN2019/110473
Authority: WO
Inventors: 王翼福
Original assignee: 王金琪
Priority date: 2019-05-09
Filing date: 2019-10-10
Publication date: 2020-11-12
Also published as: CN110066460B; CN110066460A

Abstract

The invention relates to the technical field of flame-retardant plastics, in particular to an environment-friendly flame-retardant plastic master batch capable of preventing from blooming and precipitation and a preparation method therefor. Ammonium polyphosphate and melamine polyphosphate are composited and micronized, and the surface of the micronized composite powder is coated to form an aluminum hydroxide coating film. Silicone powder is formed in the coating film while the aluminum hydroxide coating film is formed, and then is subjected to twin-screw extrusion and granulation with a filler, a lubricating additive, silicone oil, polypropylene, and a compatilizer to obtain an environment-friendly flame-retardant plastic master batch that prevents from blooming and precipitation. A aluminum salt solution is converted into the aluminum hydroxide coating film, and the dispersed silicone powder is stably coated on the surface of ammonium polyphosphate in advance, ensuring excellent hydrophobicity to the ammonium polyphosphate, and thereby enhancing the dispersibility and compatibility of the flame retardant in plastics. In particular, silicone powder has good stability and non-migration. After the coated ammonium polyphosphate is stabilized, blooming and precipitation can be effectively prevented.

Description

Environment-friendly flame-retardant plastic master batch capable of preventing blooming and precipitation and preparation method thereof

Technical field

The invention relates to the technical field of flame-retardant plastics, in particular to an environment-friendly flame-retardant plastic master batch capable of preventing blooming and precipitation and a preparation method.

Background technique

Because plastics are mainly non-polar materials, and flame retardants are generally fillers or polar melts, when flame retardants are used in plastics, the compatibility of flame retardants with plastics is poor, and it is easy to bloom and precipitate, which not only affects The appearance of the product is glossy, and it will cause the strength of the plastic product to deteriorate. Plastic products with higher requirements for flame retardants are generally electrical products, and more flame retardants need to be added. The precipitation of flame retardants seriously affects the appearance quality of plastic products. In addition, with the precipitation of flame retardants, the flame retardant function of plastic products is reduced.

Due to its excellent processability, polypropylene can be used to replace advanced engineering plastics by enhancing its rigidity and strength, and is gradually being applied on a large scale in the fields of automobiles and household appliances. However, while polypropylene is easy to process, its flame retardancy becomes a problem. Generally, polypropylene has a low fire resistance temperature and is flammable. When a large amount of flame retardant is added, the flame retardant is easy to migrate and precipitate in the polypropylene system due to the poor compatibility of the flame retardant with polypropylene. When we add flame retardant to polypropylene for injection molding, the flame retardant often precipitates on the surface of injection molded products due to the influence of heat. Produce silky white strips, affecting the appearance of the product. Some insoluble micro-particle flame retardants are easy to migrate to form bloom on the surface of the product, which directly affects the surface finish of the product. According to the prior art, it is mainly to reduce the precipitation of the flame retardant by increasing the interface compatibility of the flame retardant and the resin matrix. For example, Chinese Patent Publication No. CN101891952B discloses a non-precipitating flame-retardant masterbatch, which solves the problem of the precipitation of flame retardants by adding modified polyamide as a compatibilizer for the defect of precipitation of brominated flame retardants. However, with the development of flame retardant technology, brominated flame retardants will produce toxic and harmful gases during the production process, pollute the environment, have production safety problems, and are relatively expensive.

Ammonium polyphosphate (APP) is a phosphorus and nitrogen-based special intumescent inorganic flame retardant, which has been used in plastics, coatings and other fields. The flame retardant P-N has high content of flame-retardant elements, good thermal stability, high flame-retardant efficiency and lasting flame-retardant performance. With the global development of flame retardants in the direction of environmental protection and halogen-free, intumescent flame retardants with APP as the main raw material have become a hot spot in research and development. Therefore, ammonium polyphosphate becomes a better flame retardant. Ammonium polyphosphate has lower cost than brominated flame retardants and is environmentally friendly. However, when used in plastic products, there is a more serious precipitation than brominated flame retardants, and ammonium polyphosphate is sensitive to water. When used in flame retardants for electrical products, there is a risk of deterioration in a humid environment. In addition, ammonium polyphosphate releases a certain amount of small molecules during thermal processing of conventional plastics. Therefore, in order to promote the flame-retardant application of ammonium polyphosphate in the plastics field, it is necessary to solve the problems of heat resistance, water resistance and blooming of ammonium polyphosphate in plastics. However, it is difficult to fundamentally solve the precipitation problem of ammonium polyphosphate by using the existing single compatibilizer technology.

Summary of the invention

In view of the defect that ammonium polyphosphate is used as a plastic flame retardant to precipitate and bloom, in order to promote the large dose of ammonium polyphosphate flame retardant to be used in plastic products, the present invention proposes an environmentally friendly flame-retardant plastic master batch that prevents blooming and precipitation and its preparation method. By coating the surface of ammonium polyphosphate and melamine polyphosphate composite micropowder with aluminum hydroxide and then modifying it to enhance the water resistance and heat resistance stability of ammonium polyphosphate, and effectively prevent blooming.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

The present invention provides a preparation method of an environmentally friendly flame-retardant plastic master batch that prevents blooming and precipitation, which is characterized in that the specific preparation method is as follows:

(1) Grind the silicone powder with aluminum sulfate, and then add deionized water to obtain an aluminum sulfate composite solution in which the silicone powder is dispersed for use; wherein the mass ratio of silicone powder, aluminum sulfate, and deionized water is 1:5:20 ；

(2) Compounding ammonium polyphosphate and melamine polyphosphate in a mass ratio of 3:1, and processing by a micromachine to obtain a composite powder with a particle size of less than 5 μm;

(3) Add the composite micropowder to a closed container, fill the closed container with ammonia gas, control the temperature of the container to 35-45°C, and stir at high speed, and spray the aluminum sulfate composite liquid obtained in step (1) into the closed container with a high-pressure spray gun , The surface of the suspended composite powder is in contact with the aluminum sulfate composite liquid, and the ammonia gas gradually dissolves in the water to form a weak alkaline environment, which promotes the formation of aluminum hydroxide coating on the surface of the composite powder; discharge from a closed container and fluidize at 100-120℃ The bed is dried to obtain a composite modified ammonium polyphosphate flame retardant;

(4) Add 40-50 parts by weight of composite modified ammonium polyphosphate flame retardant, 5-10 parts by weight of filler, 0.5-1 parts by weight of lubricating aids, and 0.1-0.3 parts by weight of silicone oil into the high-speed mixer. ℃ high-speed stirring treatment for 15-20 minutes, then add 15-20 parts by weight of polypropylene and 5-10 parts by weight of compatibilizer and mix at low speed for 3-5 minutes, mix evenly, put the material into the cold mixer, stir and cool at low speed;

(5) The material cooled in step (4) is sent to the twin-screw extruder through the conveying pipeline, and an environmentally friendly flame-retardant plastic masterbatch that prevents blooming and precipitation is obtained through extrusion and granulation.

Ammonium polyphosphate (APP) is an excellent flame retardant. The flame retardant mechanism is to generate a strong dehydrating agent for polyphosphoric acid after being dehydrated by heating, which promotes the dehydration of organic surfaces to form carbides, plus the non-volatile phosphorus oxides and polyphosphoric acid produced Covering the surface of the substrate, while containing nitrogen elements, thermal decomposition releases carbon dioxide, nitrogen, ammonia and other gases, these gases are not easy to burn, blocking the supply of oxygen. It is a cheap and excellent environmentally friendly halogen-free flame retardant. The annual fee list shows that the general structural formula of total ammonium polyphosphate (APP) is (NH4) _(n+2) PnO _(3n+1) , when n=10-20, easy to dissolve in water; n=20-100, difficult to water Soluble, but sensitive to water.

Preferably, the ammonium polyphosphate in step (2) is long-chain ammonium polyphosphate with n>500, which is relatively stable at normal plastic processing temperature, but begins to decompose into phosphoric acid and ammonia above 300°C, and further Dehydrated to form polyphosphoric acid or polymetaphosphoric acid, which exhibits excellent flame retardancy.

Melamine polyphosphate (MPP) is an additive flame retardant with a wide range of applications. It is generally white, fine powder, and has a decomposition temperature of> 300°C. The PN synergy among them shows excellent flame retardancy, and its outstanding The advantages are good thermal stability, insoluble in water, low smoky, and non-hygroscopic. When used in plastics, it has excellent high temperature processing performance. It forms a foamed coke layer during endothermic decomposition and covers the surface of the burning material to isolate the air. The vaporized melamine provides an inert gas source and can dilute oxygen. And the concentration of combustible gas produced by the decomposition of high polymer, so as to achieve the purpose of flame retardant. Blended with ammonium polyphosphate shows excellent flame retardancy.

Preferably, the melamine phosphate in step (2) is a commercially available melamine polyphosphate with a phosphorus content of more than 14% and a nitrogen content of more than 38%.

Step (2) The micronizer adopts a conventional micronizer to micronize and composite the commercially available large-particle ammonium polyphosphate and melamine polyphosphate into composite micropowders with a particle size of less than 5 μm. In order to prevent material denaturation and agglomeration caused by high temperature during the miniaturization process, the grinding type miniaturization machine is carefully used. Preferably, the micromachine adopts a vortex jet mill.

Preferably, the speed of the high-speed stirring in step (3) is 800-1200 rpm, and it is preferable to fully suspend the composite micropowder so that the atomized aluminum sulfate composite liquid can fully contact. In actual operation, in order to ensure that the composite micropowder is fully suspended, the amount of composite micropowder added in the closed container does not exceed 1/3 of the volume of the closed container.

Preferably, in step (3), the closed container is filled with ammonia gas, the ammonia gas environment of the closed container is maintained, and ammonia gas is continuously filled to ensure that the ammonia gas pressure is 0.01 MPa. When the atomized aluminum sulfate composite liquid is sprayed, the ammonia The gas gradually dissolves in the water and uniformly generates aluminum hydroxide, thereby forming a uniform coating layer on the surface of the ammonium polyphosphate and melamine polyphosphate composite micropowder; different from the direct addition of ammonia, the direct addition of ammonia will cause the rapid and violent formation of aluminum hydroxide , It is difficult to coat the powder uniformly.

Further preferably, the injection amount of the aluminum sulfate composite liquid in step (3) is controlled to be 0.5-1 times the mass of the composite powder. In order to better ensure that the aluminum hydroxide coating layer is uniformly formed on the surface of the composite micropowder, the pressure of the high-pressure spray gun is 0.6-0.8MPa.

Preferably, the filler in step (4) is selected from at least one of talc powder, wollastonite powder, montmorillonite, and mica powder.

Preferably, the lubricating aid in step (4) is selected from polyethylene wax and stearic acid powder.

Preferably, the silicone oil in step (4) is selected from at least one of methyl trifluoropropyl silicone oil, methyl ethoxy silicone oil, methyl silicone oil, and ethyl silicone oil; its excellent hydrophobicity increases the composite modified polyphosphoric acid The compatibility of ammonium flame retardant and resin is beneficial to reduce the precipitation of flame retardant.

Preferably, the compatibilizer in step (4) is maleic anhydride grafted polypropylene, maleic anhydride grafted polyethylene, maleic anhydride grafted ethylene-octene copolymer, maleic anhydride grafted ethylene-propylene- One of diene copolymers.

Preferably, in step (4), the high-speed stirring speed is 400-900 rpm, and the low-speed stirring speed is 80-100 rpm.

Preferably, the twin-screw extruder in step (5) is a counter-rotating twin-screw extruder with a screw diameter of 45 mm and a length-to-diameter ratio of 20:1. The screw is set with 5 heating zones from feeding to discharging, the temperature is in order: zone 1 100-120℃, zone 2 150-160℃, zone 3 180-190℃, zone 4 160-170℃, zone 5 130-140 ℃; Use air-cooled die surface to cut pellets. The short-length-to-length ratio and counter-rotating twin-screw extruder has less shear to the material, which can avoid the premature decomposition of the composite modified ammonium polyphosphate flame retardant caused by high shear.

The present invention further provides an environmentally friendly flame-retardant plastic master batch prepared by the above method that prevents blooming and precipitation. In order to solve the defect of blooming and precipitation of ammonium polyphosphate as a flame retardant in plastics, the present invention makes ammonium polyphosphate and melamine polyphosphate composite micronized, and coats the surface of the micronized composite powder to form an aluminum hydroxide coating. While forming the aluminum hydroxide coating film, the silicone powder is formed in the coating film. On the one hand, aluminum hydroxide is coated with ammonium polyphosphate and melamine polyphosphate composite powder, so that the ammonium polyphosphate has good heat resistance. It is easy to be processed in the plastic system for thermoplastics, reducing the release of small molecules caused by thermal processing; on the other hand, the aluminum hydroxide coating increases the moisture resistance of ammonium polyphosphate, and will not be degraded by moisture when used in electrical plastics; It is important that the disperse silicone powder is stably coated on the surface of ammonium polyphosphate through the conversion of aluminum salt into aluminum hydroxide coating to give ammonium polyphosphate excellent hydrophobicity, thereby enhancing the flame retardant in the plastic In particular, the silicone powder has good stability and non-migration. The stable coating of ammonium polyphosphate can effectively prevent its blooming and precipitation.

Compared with directly adding silicone powder to modify ammonium polyphosphate, the present invention forms an aluminum hydroxide coating on the surface of ammonium polyphosphate and melamine polyphosphate composite micropowder during the process of forming aluminum hydroxide from aluminum salt, and combines the silicone The powder is stably coated on the surface of ammonium polyphosphate and melamine polyphosphate composite micropowder. It greatly increases the compatibility of the composite micropowder and the plastic, and effectively inhibits blooming and precipitation; further, the coated aluminum hydroxide is a flame-retardant functional material, which effectively synergizes the flame-retardant function.

Compared with the prior art, an environmentally-friendly flame-retardant plastic masterbatch capable of preventing blooming and precipitation and a preparation method of the present invention have outstanding features and excellent effects in:

1. In the present invention, ammonium polyphosphate and melamine polyphosphate are compounded and micronized, and the surface of the micronized composite powder is coated to form an aluminum hydroxide coating film. While forming the aluminum hydroxide coating film, the silicone powder is formed in the coating film. In the film, aluminum hydroxide is coated with ammonium polyphosphate and melamine polyphosphate composite micropowder, so that ammonium polyphosphate has good heat resistance, makes it easy to be processed in plastic systems by thermoplastics, and reduces the release of small molecules caused by thermal processing.

2. The invention is coated with aluminum hydroxide to increase the moisture resistance of ammonium polyphosphate, and will not be degraded by moisture when used in electrical plastics.

3. In the present invention, the aluminum salt is converted into aluminum hydroxide coating, the dispersed silicone powder is stably coated on the surface of ammonium polyphosphate in advance, and the ammonium polyphosphate is given excellent hydrophobicity, thereby enhancing the flame retardant in plastics. Dispersibility and compatibility. In particular, silicone powder has good stability and non-migration. After stabilizing the coated ammonium polyphosphate, it can effectively prevent its blooming and precipitation.

4. The preparation method of the present invention is simple, the process is easy to control, the effect is excellent, and it is suitable for large-scale production. The obtained plastic flame-retardant masterbatch is suitable for adding to various plastics to improve the flame retardancy and prevent the blooming and precipitation of flame retardants, especially It has better effect in polypropylene and polyamide.

Description of the drawings

Figure 1: Scanning electron micrograph of a test board prepared by using the flame-retardant masterbatch of Example 1 for PP injection molding.

Figure 2: Low-power scanning electron micrograph of a test board prepared by using the flame-retardant masterbatch of Comparative Example 1 for PP injection molding.

Figure 3: High-magnification scanning electron micrograph of a test board prepared by using the flame-retardant masterbatch of Comparative Example 1 for PP injection molding.

Detailed ways

The present invention will be further described in detail below through specific embodiments, but it should not be understood that the scope of the present invention is limited to the following examples. Without departing from the above method idea of the present invention, various substitutions or changes made based on common technical knowledge and conventional means in the field should all be included in the scope of the present invention.

Example 1

(2) The long-chain ammonium polyphosphate with n>500, the commercially available melamine polyphosphate with a phosphorus content of more than 14%, and a nitrogen content of more than 38% are compounded at a mass ratio of 3:1, and processed by a vortex jet mill to obtain the particle size Composite micropowder smaller than 5μm;

(3) Add the composite micropowder to the airtight container to ensure that the added amount of the composite micropowder in the airtight container does not exceed 1/3 of the volume of the airtight container, fill the airtight container with ammonia gas, control the temperature of the container to 45℃, and stir at 800rpm It is better to fully suspend the composite micropowder. Use a high-pressure spray gun to spray the aluminum sulfate composite liquid obtained in step (1) into a closed container with a pressure of 0.6MPa. The surface of the suspended composite micropowder is in contact with the aluminum sulfate composite liquid to maintain the closed container. Ammonia gas environment, and continuously filled with ammonia gas, to ensure that the ammonia gas pressure is 0.01MPa, the ammonia gas gradually dissolves in the water to form a weak alkaline environment, which promotes the aluminum sulfate salt solution on the surface of the composite powder to form an aluminum hydroxide coating layer; put it from a closed container The material is dried in a fluidized bed at 100°C to obtain a composite modified ammonium polyphosphate flame retardant; the injection amount of the aluminum sulfate composite liquid is controlled to 0.5 times the quality of the composite powder;

(4) Add 40 parts by weight of composite modified ammonium polyphosphate flame retardant, 5 parts by weight of talc, 0.5 parts by weight of polyethylene wax, and 0.1 parts by weight of methyl trifluoropropyl silicone oil into the high-speed mixer, and stir at 100°C. Speed 400rpm high-speed stirring for 15min, then add 15 parts by weight of polypropylene, 50 parts by weight of compatibilizer maleic anhydride grafted polypropylene, stir and mix at 80rpm for 3min at low speed, mix well, put the material into the cold mixer, stir at low speed and cool to room temperature ；

(5) The material cooled in step (4) is fed into a counter-rotating twin-screw extruder with a screw diameter of 45 mm and a length-to-diameter ratio of 20:1 through the conveying pipeline. The screw sets 5 heating zones from feeding to discharging, the temperature is in order: 120°C in zone 1, 150°C in zone 2, 180°C in zone 3, 160°C in zone 4, and 140°C in zone 5; The cold die surface is cut into pellets to obtain an environmentally friendly flame-retardant plastic master batch that prevents blooming and precipitation.

The flame-retardant plastic master batch obtained in Example 1 and PPK1708 resin were mixed uniformly at a mass ratio of 2:10, and injection molded into a flat test sample, numbered 1#, injection temperature: 200°C in zone 1, 210°C in zone 2, and zone 3 230°C; 240°C in zone 4. The obtained test board was placed at 80°C for 24 hours, and the surface of the test board was observed with a scanning electron microscope. As shown in Figure 1, the board surface had good gloss and no precipitates.

Example 2

(3) Add the composite micropowder to the closed container to ensure that the added amount of the composite micropowder in the closed container does not exceed 1/3 of the volume of the closed container, fill the closed container with ammonia gas, control the temperature of the container to 35°C, and stir at 1200rpm It is better to fully suspend the composite micropowder. Use a high-pressure spray gun to spray the aluminum sulfate composite liquid obtained in step (1) into a closed container at a pressure of 0.8MPa. The surface of the suspended composite micropowder is in contact with the aluminum sulfate composite liquid to maintain the closed container. Ammonia gas environment, and continuously filled with ammonia gas, to ensure that the ammonia gas pressure is 0.01MPa, the ammonia gas gradually dissolves in the water to form a weak alkaline environment, which promotes the aluminum sulfate salt solution on the surface of the composite powder to form an aluminum hydroxide coating layer; put it from a closed container The material is dried in a fluidized bed at 120°C to obtain a composite modified ammonium polyphosphate flame retardant; the injection amount of the aluminum sulfate composite liquid is controlled at 0.5 times the quality of the composite powder;

(4) Add 50 parts by weight of composite modified ammonium polyphosphate flame retardant, 10 parts by weight of wollastonite powder, 1 part by weight of stearic acid, and 0.2 parts by weight of methyl silicone oil into the high-speed mixer. Stir for 20 minutes, then add 20 parts by weight of polypropylene and 10 parts by weight of compatibilizer maleic anhydride grafted polyethylene, stir and mix at a low speed of 100 rpm for 5 minutes, mix well, put the material into the cold mixer, stir and cool at low speed;

(5) The material cooled in step (4) is fed into a counter-rotating twin-screw extruder with a screw diameter of 45 mm and a length-to-diameter ratio of 20:1 through the conveying pipeline. The screw is set with 5 heating zones from feeding to discharging, the temperature is in order: 100°C in zone 1, 150°C in zone 2, 180°C in zone 3, 160°C in zone 4, and 140°C in zone 5; The cold die surface is cut into pellets to obtain an environmentally friendly flame-retardant plastic master batch that prevents blooming and precipitation.

The flame-retardant plastic master batch obtained in Example 2 and PPK1708 resin were mixed uniformly at a mass ratio of 2:10, and injection molded into a flat test sample with a thickness of 16mm, numbered 2#, injection temperature: zone 1 200°C; zone 2 210°C ; Zone 3 230℃; Zone 4 240℃. According to UL 94-2006 test, vertical combustion is adopted. The instrument uses UL94 horizontal and vertical combustion test box, and the measured flame retardant level reaches V0.

Example 3

(3) Add the composite micropowder to the closed container to ensure that the added amount of the composite micropowder in the closed container does not exceed 1/3 of the volume of the closed container, fill the closed container with ammonia gas, control the temperature of the container to 45°C, and stir at 1200rpm It is better to fully suspend the composite micropowder. Use a high-pressure spray gun to spray the aluminum sulfate composite liquid obtained in step (1) into a closed container at a pressure of 0.8MPa. The surface of the suspended composite micropowder is in contact with the aluminum sulfate composite liquid to maintain the closed container. Ammonia gas environment, and continuously filled with ammonia gas, to ensure that the ammonia gas pressure is 0.01MPa, the ammonia gas gradually dissolves in the water to form a weak alkaline environment, which promotes the aluminum sulfate salt solution on the surface of the composite powder to form an aluminum hydroxide coating layer; put it from a closed container The material is dried in a fluidized bed at 120°C to obtain a composite modified ammonium polyphosphate flame retardant; the injection amount of the aluminum sulfate composite liquid is controlled at 0.8 times the quality of the composite powder;

(4) Add 50 parts by weight of composite modified ammonium polyphosphate flame retardant, 5 parts by weight of mica powder, 0.5 parts by weight of polyethylene wax, and 0.3 parts by weight of methyl ethoxy silicone oil into the high-speed mixer, and stir at 100°C. Stir at high speed at 900rpm for 20min, then add 15 parts by weight of polypropylene, 5 parts by weight of compatibilizer maleic anhydride grafted ethylene-octene copolymer, stir and mix at 80rpm for 5min at low speed, mix well, put the material into the cold mixer, and stir at low speed cool down;

(5) The material cooled in step (4) is fed into a counter-rotating twin-screw extruder with a screw diameter of 45 mm and a length-to-diameter ratio of 20:1 through the conveying pipeline. The screw sets 5 heating zones from feeding to discharging. The temperature is in order: 120°C in zone 1, 160°C in zone 2, 190°C in zone 3, 170°C in zone 4, and 140°C in zone 5; The cold die surface is cut into pellets to obtain an environmentally friendly flame-retardant plastic master batch that prevents blooming and precipitation.

Comparative example 1

(1) Add aluminum sulfate to deionized water to obtain an aluminum sulfate composite solution for use; wherein the mass ratio of aluminum sulfate to deionized water is 5:20;

(4) Add 40 parts by weight of composite modified ammonium polyphosphate flame retardant, 1 part by weight of silicone powder, 5 parts by weight of talc, 0.5 parts by weight of polyethylene wax, and 0.1 parts by weight of methyl trifluoropropyl silicone oil into high-speed mixing Stirring at a high speed of 400 rpm at 100°C for 15 minutes, and then adding 15 parts by weight of polypropylene and 50 parts by weight of the compatibilizer maleic anhydride grafted polypropylene, stirring and mixing at a low speed of 80 rpm for 3 minutes, mixing uniformly, and discharging into cold mixing Machine, low-speed stirring and cooling to room temperature;

(5) The material cooled in step (4) is fed into a counter-rotating twin-screw extruder with a screw diameter of 45 mm and a length-to-diameter ratio of 20:1 through the conveying pipeline. The screw sets 5 heating zones from feeding to discharging, the temperature is in order: 120°C in zone 1, 150°C in zone 2, 180°C in zone 3, 160°C in zone 4, and 140°C in zone 5; Cut pellets on the cold die surface to obtain an environmentally friendly flame-retardant plastic master batch.

Compared with Example 1, Comparative Example 1 did not add silicone powder to the aluminum sulfate solution, but added the silicone powder after the aluminum hydroxide coating was formed, so that a single aluminum hydroxide coating was formed, instead of adding The silicone powder is tightly coated on the surface of the composite powder, which makes the flame retardant easy to bloom and precipitate in the plastic.

The flame-retardant plastic master batch obtained in Comparative Example 1 and PPK1708 resin were mixed uniformly at a mass ratio of 2:10, and injection molded into a flat test sample, numbered 3#, injection temperature: 200°C in zone 1, 210°C in zone 2, and zone 3 230°C; 240°C in zone 4. Place the obtained test board at 80°C for 24h, and observe the surface of the test board with a scanning electron microscope. As shown in Figure 2, the plate surface has obvious crystal points. Through further magnification observation, as shown in Figure 3, the precipitated surface The crystal point size is close to 5μm, which affects the gloss and smoothness of plastic products.

Claims

A preparation method of an environmentally friendly flame-retardant plastic master batch capable of preventing blooming and precipitation, which is characterized in that the specific preparation method is as follows:

(1) Grind the silicone powder with aluminum sulfate, and then add deionized water to obtain an aluminum sulfate composite solution in which the silicone powder is dispersed for use; wherein the mass ratio of silicone powder, aluminum sulfate, and deionized water is 1:5:20 ；

(2) Compounding ammonium polyphosphate and melamine polyphosphate in a mass ratio of 3:1, and processing by a micromachine to obtain a composite powder with a particle size of less than 5 μm;

(3) Add the composite micropowder to a closed container, fill the closed container with ammonia gas, control the temperature of the container to 35-45°C, and stir at high speed, and spray the aluminum sulfate composite liquid obtained in step (1) into the closed container with a high-pressure spray gun , The surface of the suspended composite powder is in contact with the aluminum sulfate composite liquid, and the ammonia gas gradually dissolves in the water to form a weak alkaline environment, which promotes the formation of aluminum hydroxide coating on the surface of the composite powder; discharge from a closed container and fluidize at 100-120℃ The bed is dried to obtain a composite modified ammonium polyphosphate flame retardant;

(4) Add 40-50 parts by weight of composite modified ammonium polyphosphate flame retardant, 5-10 parts by weight of filler, 0.5-1 parts by weight of lubricating aids, and 0.1-0.3 parts by weight of silicone oil into the high-speed mixer. ℃ high-speed stirring treatment for 15-20 minutes, then add 15-20 parts by weight of polypropylene and 5-10 parts by weight of compatibilizer and mix at low speed for 3-5 minutes, mix evenly, put the material into the cold mixer, stir and cool at low speed;

(5) The material cooled in step (4) is sent to the twin-screw extruder through the conveying pipeline, and an environmentally friendly flame-retardant plastic masterbatch that prevents blooming and precipitation is obtained through extrusion and granulation.
The method for preparing an environmentally friendly flame-retardant plastic masterbatch that prevents blooming and precipitation according to claim 1, wherein the general structural formula of ammonium polyphosphate is (NH4) (n+2) PnO (3n+1) In step (2), the ammonium polyphosphate is long-chain ammonium polyphosphate with n>500.
The method for preparing an environmentally-friendly flame-retardant plastic masterbatch capable of preventing blooming and precipitation according to claim 1, characterized in that: in step (2), the melamine phosphate is selected from commercially available phosphorus content greater than 14% and nitrogen content greater than 38%. % Melamine polyphosphate.
The method for preparing an environmentally-friendly flame-retardant plastic masterbatch capable of preventing blooming and precipitation according to claim 1, characterized in that: in step (2), the micro-machine adopts a vortex jet mill.
The preparation method of an environmentally friendly flame-retardant plastic masterbatch that prevents blooming and precipitation according to claim 1, characterized in that: in step (3), the high-speed stirring speed is 800-1200rpm, and the amount of composite micropowder added in the closed container Does not exceed 1/3 of the volume of the closed container.
The preparation method of an environmentally friendly flame-retardant plastic masterbatch with anti-blooming precipitation according to claim 1, characterized in that: step (3) fill the airtight container with ammonia gas, maintain the ammonia gas environment of the airtight container, and continuously fill Enter the ammonia gas to ensure that the ammonia gas pressure is 0.01 MPa; the pressure of the high-pressure spray gun is 0.6-0.8 MPa. Further preferably, the injection amount of the aluminum sulfate composite liquid in step (3) is controlled to be 0.5-1 times the mass of the composite powder. In order to better ensure that the aluminum hydroxide coating layer is uniformly formed on the surface of the composite micropowder, the pressure of the high-pressure spray gun is 0.6-0.8MPa.
The method for preparing an environmentally friendly flame-retardant plastic masterbatch that prevents blooming and precipitation according to claim 1, wherein the filler in step (4) is selected from talc powder, wollastonite powder, montmorillonite, and mica powder. At least one of; the lubricating aid is selected from polyethylene wax and stearic acid powder; the silicone oil is selected from methyl trifluoropropyl silicone oil, methyl ethoxy silicone oil, methyl silicone oil, ethyl silicone oil The compatibilizer is maleic anhydride grafted polypropylene, maleic anhydride grafted polyethylene, maleic anhydride grafted ethylene-octene copolymer, maleic anhydride grafted ethylene-propylene-two One of olefin copolymers.
The method for preparing an environmentally friendly flame-retardant plastic masterbatch that prevents blooming and precipitation according to claim 1, characterized in that: in step (4), the high-speed stirring speed is 400-900rpm, and the low-speed stirring speed is 80- 100rpm.
The method for preparing an environmentally friendly flame-retardant plastic masterbatch capable of preventing blooming and precipitation according to claim 1, characterized in that: in step (5), the twin-screw extruder selects a screw diameter of 45mm and a length-to-diameter ratio of 20:1. A twin-screw extruder with a shorter and longer warp ratio; the screw sets 5 heating zones from feeding to discharging, the temperature is in order: zone 1 100-120℃, zone 2 150-160℃, zone 3 180-190℃, 4 Zone 160-170℃, zone 5 130-140℃; use air-cooled die surface to cut pellets.
An environmentally friendly flame-retardant plastic masterbatch capable of preventing blooming and precipitation, which is characterized in that it is prepared by the method of any one of claims 1-9.