A modified polyamide flame-retardant plastic for automobile water chamber and preparation method thereof

Abstract

The present application relates to the technical field of polymer material processing and synthesis, and discloses a modified polyamide flame retardant plastic for automobile water chamber and its preparation method, wherein the modified polyamide flame retardant plastic comprises the following raw materials: polyamide, flame retardant, inorganic filler, reinforcing component; based on the reinforcing component, the reinforcing component comprises reinforcing fiber with a weight percentage of 90-95%, and the rest is alkali-free glass fiber; the reinforcing fiber is obtained by crushing alkali-free glass fiber cloth and sisal cloth of equal area after adhesive, and the adhesive is acetal glue dispersed with antimony oxide. The preparation method is: the remaining raw materials except inorganic filler and reinforcing component are mixed to obtain mixture B; mixture B is added from the main feed port of a twin-screw extruder, and the inorganic filler and reinforcing component are mixed and added at the side feed port, and the modified polyamide flame retardant plastic is obtained by melt extrusion granulation. The modified polyamide flame retardant plastic in the present application effectively improves the problems of poor flame retardancy and mechanical properties of polyamide.

Description

Technical Field

[0001] The present application belongs to the technical field of polymer material processing and synthesis, and in particular relates to a modified polyamide flame-retardant plastic for automobile water chambers and a preparation method thereof. Background Art

[0002] The car radiator is commonly known as the car water chamber. It consists of three parts: the water inlet chamber, the water outlet chamber and the radiator core. The materials of the water inlet and outlet chambers are plastic parts, and the radiator core is mostly made of aluminum. The radiator is filled with coolant, which flows in the radiator core and the air passes outside the radiator core. The hot coolant cools down due to the heat dissipation to the air, and the cold air heats up due to the heat dissipated by the coolant, achieving the heat dissipation effect in turn.

[0003] Since the environment of each part in the automobile water chamber is a high and low temperature coolant environment, the material must be resistant to the corrosion of ethylene glycol and other chemicals. At the same time, the parts must not crack during the assembly process, and high requirements are placed on the mechanical properties and dimensional stability of the material.

[0004] Polyamide (i.e. nylon) is widely used in many fields of producing structural components due to its good mechanical properties, chemical resistance, good processability, low density, etc., especially in the automotive field, and is also the best choice for automotive water chamber plastic parts. However, even though polyamide has a certain degree of flame retardancy and is a self-extinguishing material, it is still flammable; as a raw material for automotive water chamber plastic parts, the flame retardancy and mechanical properties of polyamide need to be improved. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a modified polyamide flame retardant plastic for automobile water chambers and a preparation method thereof, so as to solve the problem that polyamide in the prior art, as the raw material of automobile water chamber plastic parts, has poor flame retardancy and mechanical properties.

[0006] In order to achieve the above objectives, in a first aspect, the present application provides a modified polyamide flame-retardant plastic for an automobile water chamber, using the following technical method:

[0007] A modified polyamide flame-retardant plastic for automobile water chambers, comprising the following raw materials in parts by weight: 450-900 parts of polyamide; 90-160 parts of flame retardant; 50-200 parts of inorganic filler; 50-200 parts of reinforcing component;

[0008] The polyamide is one or both of nylon 6 and nylon 66;

[0009] The flame retardant is one or more of a phosphorus flame retardant, a halogen flame retardant, and a metal hydroxide flame retardant;

[0010] The inorganic filler is at least one of talc, calcium carbonate, wollastonite, kaolin, silicon dioxide, montmorillonite, barium sulfate and mica powder;

[0011] Based on the reinforcing component, the reinforcing component includes 90-95% by weight of reinforcing fibers, and the rest is alkali-free glass fibers;

[0012] The reinforcing fibers are obtained by crushing equal-area alkali-free glass fiber cloth and sisal cloth after applying an adhesive, and the adhesive is acetal glue dispersed with antimony oxide;

[0013] The preparation method of the reinforcing fiber comprises the following steps:

[0014] S1; dispersing 4-8g of antimony oxide into 10-20ml of acetal glue to obtain an adhesive; and the antimony oxide is antimony trioxide or antimony pentoxide;

[0015] S2: Equal areas of alkali-free glass fiber cloth and sisal cloth are bonded face to face with an adhesive and then crushed to obtain reinforcing fibers.

[0016] Furthermore, the acetal glue is X98-11 or X98-14.

[0017] Furthermore, the phosphorus-based flame retardant is specifically one or both of red phosphorus masterbatch and resorcinol bis(diphenyl phosphate).

[0018] Furthermore, the halogen flame retardant is at least one of decabromodiphenylethane, brominated epoxy resin, and brominated polystyrene.

[0019] Furthermore, the modified polyamide flame retardant plastic also includes 10-30 parts of an adsorbent, and the adsorbent is at least one of clay and molecular sieve.

[0020] Furthermore, the modified polyamide flame retardant plastic also includes 2-6 parts of a copper salt composite heat stabilizer.

[0021] In a second aspect, the present application provides a method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber, using the following technical method:

[0022] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber comprises the following steps:

[0023] The inorganic filler and the reinforcing component are mixed to obtain a mixture A, and the remaining raw materials are mixed to obtain a mixture B;

[0024] The mixture B is added from the main feeding port of the twin-screw extruder, and the mixture A is added from the side feeding port of the twin-screw extruder, and granulated by melt extrusion to obtain a modified polyamide flame-retardant plastic;

[0025] The temperature of the melt extrusion of the twin-screw extruder is 250°C to 310°C.

[0026] Compared with the prior art, this application has the following technical effects:

[0027] 1. The present application discloses a modified polyamide flame-retardant plastic for automobile water chambers. The flame retardant in the raw materials can effectively improve the flame retardancy of the polyurethane plastic. The addition of inorganic fillers and reinforcing components can effectively improve the mechanical properties, especially the reinforcing fibers in the reinforcing components.

[0028] The reinforcing fibers disclosed in the present application are obtained by crushing equal-area alkali-free glass fiber cloth and sisal cloth after being bonded with an adhesive, and the adhesive is acetal glue dispersed with antimony oxide: the main components of the alkali-free glass fiber cloth and sisal cloth are glass fiber and sisal fiber, and the addition of the two can effectively improve the mechanical properties of modified polyamide flame-retardant plastics; the two are bonded with an adhesive and then crushed to obtain reinforcing fibers, so that each portion of reinforcing fibers at the macroscopic or microscopic level includes glass fiber and sisal fiber, so that the two are dispersed in various parts of the plastic system and can work synergistically in each part to enhance the mechanical properties of the plastic.

[0029] More importantly, antimony oxide in the reinforcing fiber raw material is an inorganic flame retardant, which has flame retardant properties as well as the mechanical properties of inorganic substances; acetal glue (polyvinyl alcohol acetal glue) is an aerospace grade adhesive that can be used for bonding glass, metal, paper, fiber and plastic, and it itself has excellent light resistance, water resistance, heat resistance, cold resistance and toughness; therefore, using acetal glue dispersed with antimony oxide as an adhesive can make the adhesive itself have relatively good mechanical properties and heat resistance and flame retardant properties.

[0030] The use of adhesives to bond glass fibers and sisal fibers can further improve the mechanical properties and heat resistance and flame retardancy of the reinforced fibers. Plastics are more flammable after the addition of glass fibers and other substances. The use of the adhesive in this application can improve the phenomenon that the addition of glass fibers makes plastics more flammable, so that the modified polyamide flame retardant plastic can simultaneously enhance the flame retardancy and mechanical properties.

[0031] In summary, the modified polyamide flame-retardant plastic used in the automobile water chamber of the present application can improve the flame retardant properties and mechanical properties of the plastic at the same time, and at the same time solves the problem of poor flame retardant properties and mechanical properties of polyamide as the raw material of automobile water chamber plastic parts in the prior art.

[0032] 2. The addition of adsorbents can absorb the odor of organic compounds volatilized at high temperatures, which can improve the air quality in the car to a certain extent.

[0033] 3. The copper salt composite heat stabilizer in the raw materials has a very good stabilizing effect on polyamide under high-temperature oxidation conditions, which can effectively improve the heat resistance stability of the amide bond, thereby modifying the heat resistance of polyamide flame-retardant plastics. DETAILED DESCRIPTION

[0034] In the embodiment of the present application, the sisal cloth is a linen cloth woven from sisal fibers;

[0035] In the embodiment of the present application, the alkali-free glass fiber cloth is an alkali-free electronic pole desizing glass fiber cloth insulating glass fiber cloth;

[0036] The specific model of alkali-free glass fiber is ECS301CL-3, and the manufacturer is CPIC;

[0037] In the preparation method of the reinforcing fiber, a cloth crusher is used for crushing to obtain reinforcing fibers of 5-15 mm.

[0038] Preparation example of reinforcing fiber

[0039] Preparation Example 1

[0040] A method for preparing a reinforcing fiber comprises the following steps:

[0041] S1; 4 g of antimony oxide is dispersed in 10 ml of acetal glue X98-11 to obtain an adhesive; and the antimony oxide is antimony trioxide;

[0042] S2: Equal areas of alkali-free glass fiber cloth and sisal cloth are bonded face to face with an adhesive and then crushed to obtain reinforcing fibers.

[0043] Preparation Example 2

[0044] A method for preparing a reinforcing fiber comprises the following steps:

[0045] S1; 8g of antimony oxide is dispersed in 20ml of acetal glue X98-14 to obtain an adhesive; and the antimony oxide is antimony pentoxide;

[0046] S2: Equal areas of alkali-free glass fiber cloth and sisal cloth are bonded face to face with an adhesive and then crushed to obtain reinforcing fibers.

[0047] Preparation Example 3

[0048] A method for preparing a reinforcing fiber comprises the following steps:

[0049] S1; 6g of antimony oxide is dispersed in 15ml of acetal glue X98-14 to obtain an adhesive; and the antimony oxide is antimony trioxide;

[0050] S2: Equal areas of alkali-free glass fiber cloth and sisal cloth are bonded face to face with an adhesive and then crushed to obtain reinforcing fibers.

[0051] Comparative preparation example of reinforced fiber

[0052] Comparative Preparation Example 1

[0053] A method for preparing reinforcing fiber is carried out according to the method in Preparation Example 3, except that the sisal cloth in S2 is replaced by an alkali-free glass fiber cloth of the same area.

[0054] Comparative Preparation Example 2

[0055] A method for preparing reinforcing fibers is carried out according to the method in Preparation Example 3, except that the alkali-free glass fiber cloth in S2 is replaced by sisal cloth of the same area. Example

[0056] Example 1

[0057] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber comprises the following steps:

[0058] Mixing 50 kg of inorganic filler and 50 kg of reinforcing component to obtain mixture A, and mixing 450 kg of polyamide, 90 kg of flame retardant and 10 kg of adsorbent to obtain mixture B;

[0059] Based on the reinforcing component, the reinforcing component includes 90% by weight of reinforcing fibers prepared by the method in Preparation Example 1, and the rest is alkali-free glass fibers;

[0060] The mixture B is added from the main feeding port of the twin-screw extruder, and the mixture A is added from the side feeding port of the twin-screw extruder, and granulated by melt extrusion to obtain a modified polyamide flame retardant plastic; and the melt extrusion temperature of the twin-screw extruder is 250°C.

[0061] The polyamide is nylon 6;

[0062] The flame retardant is a phosphorus-based flame retardant, and the phosphorus-based flame retardant is specifically obtained by mixing red phosphorus masterbatch and resorcinol bis(diphenyl phosphate) in a weight ratio of 1:1;

[0063] The inorganic filler is obtained by mixing calcium carbonate, wollastonite and silicon dioxide in a weight ratio of 1:1:1;

[0064] The adsorbent is clay.

[0065] Example 2

[0066] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber comprises the following steps:

[0067] 200 kg of inorganic filler and 200 kg of reinforcing component were mixed to obtain mixture A, and 900 kg of polyamide, 160 kg of flame retardant and 30 kg of adsorbent were mixed to obtain mixture B;

[0068] Based on the reinforcing component, the reinforcing component includes 95% by weight of reinforcing fibers prepared by the method in Preparation Example 1, and the rest is alkali-free glass fibers;

[0069] The mixture B is added from the main feed port of the twin-screw extruder, and the mixture A is added from the side feed port of the twin-screw extruder, and granulated by melt extrusion to obtain a modified polyamide flame-retardant plastic; and the melt extrusion temperature of the twin-screw extruder is 310° C.;

[0070] The polyamide is nylon 66;

[0071] The flame retardant is a halogen flame retardant, and the halogen flame retardant is specifically obtained by mixing decabromodiphenylethane, brominated epoxy resin, and brominated polystyrene in a weight ratio of 1:1:1;

[0072] The inorganic filler is obtained by mixing talcum powder, kaolin and mica powder in a weight ratio of 1:1:1;

[0073] The adsorbent is molecular sieve.

[0074] Example 3

[0075] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber comprises the following steps:

[0076] 150 kg of inorganic filler and 150 kg of reinforcing component were mixed to obtain mixture A, and 600 parts of polyamide, 120 kg of flame retardant and 15 kg of adsorbent were mixed to obtain mixture B;

[0077] Based on the reinforcing component, the reinforcing component includes 93% by weight of reinforcing fibers prepared by the method in Preparation Example 1, and the rest is alkali-free glass fibers;

[0078] The mixture B is added from the main feeding port of the twin-screw extruder, and the mixture A is added from the side feeding port of the twin-screw extruder, and granulated by melt extrusion to obtain a modified polyamide flame retardant plastic; and the melt extrusion temperature of the twin-screw extruder is 280°C.

[0079] The polyamide is obtained by mixing nylon 6 and nylon 66 in a weight ratio of 1:1;

[0080] The flame retardant is obtained by mixing red phosphorus masterbatch and decabromodiphenylethane in a weight ratio of 1:1;

[0081] The inorganic filler is obtained by mixing barium sulfate, wollastonite and mica powder in a weight ratio of 1:1:1;

[0082] The adsorbent is obtained by mixing molecular sieve and clay in equal weight ratio.

[0083] Example 4

[0084] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that mixture B also includes 2 kg of a copper salt composite heat stabilizer.

[0085] Example 5

[0086] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that the mixture B also includes 6 kg of a copper salt composite heat stabilizer

[0087] Example 6

[0088] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that mixture B also includes 4 kg of a copper salt composite heat stabilizer.

[0089] Comparative Example

[0090] Comparative Example 1

[0091] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that the reinforcing fiber in the mixture A is prepared according to the method in Comparative Preparation Example 1.

[0092] Comparative Example 2

[0093] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that the reinforcing fiber in the mixture A is prepared according to the method in Comparative Preparation Example 2.

[0094] Comparative Example 3

[0095] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that the reinforcing fiber in mixture A is replaced by alkali-free glass fiber in equal weight.

[0096] Comparative Example 4

[0097] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that the reinforcing fiber in mixture A is replaced by sisal fiber in equal weight.

[0098] Comparative Example 5

[0099] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that the weight of the reinforcing fibers in mixture A is replaced by a mixture of alkali-free glass fibers and sisal fibers, and the weight ratio of the alkali-free glass fibers to the sisal fibers is 1:1.

[0100] Comparative Example 6

[0101] A method for preparing a modified polyamide flame-retardant plastic for an automobile water chamber is carried out according to the method in Example 3, except that an equal weight of the reinforcing component in the mixture A is replaced by an inorganic filler.

[0102] Performance testing

[0103] The modified polyamide flame retardant plastics prepared according to the methods of Examples 1-6 and Comparative Examples 1-6 were tested for tensile properties and flame retardant properties; the test results are shown in Table 1.

[0104] Among them, tensile properties: tested according to GB / T 1040.1-2006 standard, tensile rate 10mm / min;

[0105] Flame retardant performance: tested according to GB / T2406-93 plastic combustion performance test method.

[0106] Table 1: Test results of tensile properties and flame retardant properties

[0107] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Tensile strength (MPa) 176 178 178 177 177 178 Oxygen index% 33 33 33 34 34 34 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Tensile strength (MPa) 158 157 136 136 149 125 Oxygen index% 31 31 25 25 25 26

[0108] Combining the preparation methods of the modified polyamide flame retardant plastics in Example 3 and Comparative Examples 3-6, and combining their data in Table 1, it can be seen that compared with the preparation methods of the modified polyamide flame retardant plastics in Comparative Examples 3-6, the raw materials of the modified polyamide flame retardant plastics in Example 3 all contain reinforcing fibers, while Comparative Examples 3-6 do not include reinforcing fibers. According to the data in Table 1, it can be explained that the flame retardant properties and oxygen index of the polyamide flame retardant plastics in Example 3 containing reinforcing fibers in the raw materials are significantly better than those of the polyamide flame retardant plastics in Comparative Examples 3-6 without reinforcing fibers. The reason is that the raw materials in Example 3 not only contain flame retardants to effectively improve the flame retardant properties of polyurethane plastics, but also the addition of inorganic fillers and reinforcing components can effectively improve the mechanical properties. More importantly, it contains the reinforcing fibers disclosed in the reinforcing components of this application.

[0109] The reinforcing fibers disclosed in the present application are obtained by crushing equal-area alkali-free glass fiber cloth and sisal cloth after being bonded with an adhesive, and the adhesive is acetal glue dispersed with antimony oxide: the main components of the alkali-free glass fiber cloth and sisal cloth are glass fiber and sisal fiber, and the addition of the two can effectively improve the mechanical properties of modified polyamide flame-retardant plastics; the two are bonded with an adhesive and then crushed to obtain reinforcing fibers, so that each portion of reinforcing fibers at the macroscopic or microscopic level includes glass fiber and sisal fiber, so that the two are dispersed in various parts of the plastic system and can work synergistically in each part to enhance the mechanical properties of the plastic.

[0110] More importantly, antimony oxide in the reinforcing fiber raw material is an inorganic flame retardant, which has flame retardant properties as well as the mechanical properties of inorganic materials; acetal glue (polyvinyl alcohol acetal glue) is an aerospace grade adhesive that can be used for bonding glass, metal, paper, fiber and plastic, and it has excellent light resistance, water resistance, heat resistance, cold resistance and toughness; therefore, using acetal glue dispersed with antimony oxide as an adhesive can make the adhesive itself have relatively good mechanical properties and heat resistance and flame retardant properties;

[0111] Adhesives are used to bond glass fibers and sisal fibers to form a structure in which inorganic flame retardants are wrapped between the glass fibers and the sisal fibers. When such a structure is dispersed in a modified polyamide flame-retardant plastic system, the mechanical properties, heat resistance and flame retardancy of the reinforced fibers can be significantly improved. In addition, plastics are more flammable after the addition of glass fibers and other substances. The use of the adhesive in this application can improve the phenomenon that the addition of glass fibers makes plastics more flammable, so that the modified polyamide flame-retardant plastic can simultaneously enhance the flame retardant properties and mechanical properties, and its flame retardant properties can even reach a flame-retardant level.

[0112] Combined with the preparation methods of Example 3 and Comparative Examples 1-2 and the data of the three in Table 1, it can be found that: compared with the preparation method of the modified polyamide flame retardant plastic in Comparative Examples 1-2, the reinforcing fibers in Example 3 are obtained by bonding equal areas of alkali-free glass fiber cloth and sisal cloth face to face with an adhesive and then crushing them; the reinforcing fibers in Comparative Example 1 do not include sisal cloth, and the reinforcing fibers in Comparative Example 2 do not include alkali-free glass fiber cloth.

[0113] By comparing the data of Example 3 and Comparative Examples 1-2 in Table 1, it can be seen intuitively that the flame retardancy of the modified polyamide flame retardant plastic in Example 3 is slightly better than that of the modified polyamide flame retardant plastic in Comparative Examples 1-2, and the tensile strength is significantly better than that of the modified polyamide flame retardant plastic in Comparative Examples 1-2. Further explanation: The preparation of reinforcing fibers according to the method disclosed in the present application can improve the flame retardancy and mechanical properties of the modified polyamide flame retardant plastic.

[0114] Combining the preparation methods of the modified polyamide flame retardant plastics in Examples 3 and 4-6, and combining their data in Table 1, it can be seen that compared with Example 3, the heat resistance in Example 4-6 is further improved; and different from Example 3, a copper salt composite heat stabilizer is added to the modified polyamide flame retardant plastic raw material in Examples 4-6, indicating that the copper salt composite heat stabilizer has a very good stabilizing effect on polyamide under high temperature oxidation conditions, and can effectively improve the heat stability of the amide bond, thereby further improving the heat resistance of the modified polyamide flame retardant plastic.

[0115] In summary, the modified polyamide flame-retardant plastic obtained by the preparation method disclosed in the present application not only has excellent mechanical properties, but is also a highly flame-retardant product with an oxygen index ≥ 32, which is a flame-retardant grade. It solves the problem of poor flame retardancy and mechanical properties of polyamide as a raw material for automobile water chamber plastic parts in the prior art.

[0116] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed. However, as long as it is within the scope of the claims of the present application, it shall be protected by the patent law.

Claims

1. A modified polyamide flame retardant plastic for automobile water chamber, characterized in that: The invention comprises the following raw materials in parts by weight: 450-900 parts of polyamide; 90-160 parts of flame retardant; 50-200 parts of inorganic filler; 50-200 parts of reinforcing component; The polyamide is one or both of nylon 6 and nylon 66; The flame retardant is one or more of a phosphorus flame retardant, a halogen flame retardant, and a metal hydroxide flame retardant; The inorganic filler is at least one of talc, calcium carbonate, wollastonite, kaolin, silicon dioxide, montmorillonite, barium sulfate and mica powder; Based on the reinforcing component, the reinforcing component includes 90-95% by weight of reinforcing fibers, and the rest is alkali-free glass fibers; The reinforcing fibers are obtained by crushing equal-area alkali-free glass fiber cloth and sisal cloth after applying an adhesive, and the adhesive is acetal glue dispersed with antimony oxide; The preparation method of the reinforcing fiber comprises the following steps: S1; dispersing 4-8g of antimony oxide into 10-20ml of acetal glue to obtain an adhesive; and the antimony oxide is antimony trioxide or antimony pentoxide; S2: Equal areas of alkali-free glass fiber cloth and sisal cloth are bonded face to face with an adhesive and then crushed to obtain reinforcing fibers.

2. The modified polyamide flame retardant plastic for automobile water chamber according to claim 1, characterized in that: The acetal glue is X98-11 or X98-14.

3. The modified polyamide flame retardant plastic for automobile water chamber according to claim 1, characterized in that: The phosphorus-based flame retardant is specifically one or both of red phosphorus masterbatch and resorcinol bis(diphenyl phosphate).

4. The modified polyamide flame retardant plastic for automobile water chamber according to claim 1, characterized in that: The halogen flame retardant is at least one of decabromodiphenylethane, brominated epoxy resin and brominated polystyrene.

5. The modified polyamide flame retardant plastic for automobile water chamber according to claim 1, characterized in that: The modified polyamide flame retardant plastic further comprises 10-30 parts of an adsorbent, and the adsorbent is at least one of clay and molecular sieve.

6. The modified polyamide flame retardant plastic for automobile water chamber according to claim 1, characterized in that: The modified polyamide flame retardant plastic also includes 2-6 parts of a copper salt composite heat stabilizer.

7. A method for preparing a modified polyamide flame-retardant plastic for automobile water chamber according to any one of claims 1 to 6, characterized in that: The following steps are involved: The inorganic filler and the reinforcing component are mixed to obtain a mixture A, and the remaining raw materials are mixed to obtain a mixture B; The mixture B is added from the main feeding port of the twin-screw extruder, and the mixture A is added from the side feeding port of the twin-screw extruder, and granulated by melt extrusion to obtain a modified polyamide flame-retardant plastic; The temperature of the melt extrusion of the twin-screw extruder is 250°C to 310°C.