Extruded flame-retardant plastic pipe and method for producing the same

Abstract

This invention relates to the field of plastic pipe technology, and proposes an extruded flame-retardant plastic pipe and its preparation method. An extruded flame-retardant plastic pipe comprises the following raw materials in parts by weight: 100 parts polypropylene, 10-15 parts ethylene-octene copolymer, 2-4 parts glass fiber, 8-10 parts flame retardant, and 3-5 parts additives. The flame retardant is composed of brominated styrene and antimony trioxide in a mass ratio of 3-4:1. The brominated styrene is composed of first brominated styrene and second brominated styrene, and the first and second brominated styrene have different weight-average molecular weights. This technical solution solves the problem of poor flame-retardant performance of plastic pipes in related technologies.

Description

Technical Field

[0001] This invention relates to the field of plastic pipe technology, specifically to an extruded flame-retardant plastic pipe and its preparation method. Background Technology

[0002] Plastic pipes, with their advantages of light weight, corrosion resistance, convenient construction, low cost, and energy and material conservation, have been widely used in many core fields such as construction, municipal engineering, water conservancy, and power. However, most conventional plastic pipes have weak flame retardant properties and low oxygen index, making them highly flammable in high-temperature, open-flame, or accidental fire scenarios.

[0003] Plastic pipes that do not meet flame retardant standards are prone to fire hazards due to electrical short circuits, high temperatures in equipment, etc., and may even cause power outages, affecting public safety and the stability of industrial production. If the flame retardant properties of plastic pipes are insufficient, the fire will spread rapidly when burning, further increasing the casualties and property losses caused by the fire.

[0004] Therefore, it is very necessary to develop a highly flame-retardant extruded plastic pipe. Summary of the Invention

[0005] This invention proposes an extruded flame-retardant plastic pipe and its preparation method, which solves the problem of poor flame-retardant performance of plastic pipes in related technologies.

[0006] The technical solution of the present invention is as follows: The present invention proposes an extruded flame-retardant plastic pipe, comprising the following raw materials in parts by weight: 100 parts of polypropylene, 10-15 parts of ethylene-octene copolymer, 2-4 parts of glass fiber, 8-10 parts of flame retardant, and 3-5 parts of additives. The flame retardant is composed of brominated styrene and antimony trioxide in a mass ratio of 3-4:1. The brominated styrene is composed of first brominated styrene and second brominated styrene, and the first brominated styrene and the second brominated styrene have different weight-average molecular weights.

[0007] As a further technical solution, the weight-average molecular weight of the first brominated styrene is 40,000, and the weight-average molecular weight of the second brominated styrene is 150,000.

[0008] As a further technical solution, the mass ratio of the first brominated styrene to the second brominated styrene is 2:2~3.

[0009] In the extruded flame-retardant plastic pipe of this invention, the first brominated styrene has a weight-average molecular weight of 40,000, and the second brominated styrene has a weight-average molecular weight of 150,000, with a mass ratio of 2:2~3. The low molecular weight brominated styrene has a moderate decomposition temperature and can quickly release flame-retardant active free radicals when heated, rapidly capturing active groups in the combustion chain reaction and achieving rapid initial flame suppression. The high molecular weight brominated styrene has stronger thermal stability and can continuously exert a flame-retardant effect in the high-temperature combustion stage, extending the flame-retardant effect. Under the appropriate ratio, the two achieve highly efficient flame retardancy throughout the entire stage from low temperature to high temperature. Combined with antimony trioxide, it further promotes the formation of a dense and continuous char layer, effectively blocking heat transfer and the escape of combustible gases, and improving the flame-retardant performance of the extruded plastic pipe.

[0010] As a further technical solution, the additive is composed of an antioxidant and a lubricant in a mass ratio of 1:2~3.

[0011] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0012] As a further technical solution, the lubricant includes one or both of polyethylene wax and zinc stearate.

[0013] As a further technical solution, the polypropylene is talc-filled polypropylene, and the talc filling amount is 20wt%~25wt%.

[0014] In the extruded flame-retardant plastic pipe of this invention, the talc content in the polypropylene is 20wt%~25wt%, which can effectively improve the strength of the plastic pipe. If the talc content is less than 20wt%, the reinforcing effect on the matrix is ​​insufficient, the rigidity and structural strength of the pipe are low, and it is prone to deformation, failing to meet the strength requirements. If the talc content is higher than 25wt%, it will increase the internal interface defects of the material, significantly reduce the toughness, and also lead to reduced melt fluidity, making extrusion molding difficult and prone to internal stress cracking. By controlling the talc content at 20wt%~25wt%, its reinforcing effect can be fully utilized while maintaining the material's good toughness and processing performance, thus improving the strength of the extruded flame-retardant plastic pipe.

[0015] As a further technical solution, the glass fiber has a diameter of 8~12μm and a length of 3~5mm.

[0016] As a further technical solution, the antimony trioxide has an α-crystal form and a particle size of 400-800 mesh.

[0017] The present invention also proposes a method for preparing an extruded flame-retardant plastic pipe, which includes the following steps: mixing the raw materials evenly and extruding them to obtain the extruded flame-retardant plastic pipe.

[0018] The working principle and beneficial effects of this invention are as follows: In this invention, the flame retardant in the extruded flame-retardant plastic tube is composed of brominated styrene and antimony trioxide. A compound of first- and second-brominated styrene with different weight-average molecular weights is used as the main flame-retardant components, synergistically forming a highly efficient flame-retardant system to improve the flame-retardant performance of the extruded plastic tube. Brominated styrene with different molecular weights can undergo stepwise decomposition and continuously release flame-retardant active components during thermal combustion, enabling it to more effectively capture free radicals in the combustion chain reaction and interrupt the combustion process. Simultaneously, it works synergistically with antimony trioxide to promote the rapid formation of a dense char layer and block the transfer of heat and combustible gases, effectively improving the flame-retardant performance of the extruded plastic tube. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] In the following examples and comparative examples: Ethylene-octene copolymer: model number 8407; Glass fiber: 10μm in diameter and 3mm in length; First-brominated styrene: weight average molecular weight 40,000, bromine content 66%; Second bromide styrene: weight average molecular weight 150,000, bromine content 66%; Antimony trioxide: crystal form is α crystal, particle size is 400 mesh.

[0021] Example 1 An extruded flame-retardant plastic pipe comprises the following raw materials in parts by weight: 100 parts polypropylene, 10 parts ethylene-octene copolymer, 2 parts glass fiber, 8 parts flame retardant, and 3 parts additives. The polypropylene is talc-filled polypropylene with a talc content of 20 wt% and the model is PP CS 2-8120. The flame retardant consists of brominated styrene and antimony trioxide in a mass ratio of 3:1; Brominated styrene consists of styrene-1 bromide and styrene-2 ​​bromide in a mass ratio of 2:2; The additives consist of antioxidant 1010 and zinc stearate in a mass ratio of 1:2; A method for preparing an extruded flame-retardant plastic pipe includes the following steps: mixing raw materials evenly, extruding and molding to obtain an extruded flame-retardant plastic pipe.

[0022] Example 2 An extruded flame-retardant plastic pipe comprises the following raw materials in parts by weight: 100 parts polypropylene, 12 parts ethylene-octene copolymer, 3 parts glass fiber, 9 parts flame retardant, and 4 parts additives. The polypropylene is talc-filled polypropylene with a talc content of 20 wt% and the model is PP CS 2-8120. The flame retardant consists of brominated styrene and antimony trioxide in a mass ratio of 3:1; Brominated styrene consists of styrene-1 bromide and styrene-2 ​​bromide in a mass ratio of 2:2; The additives consist of antioxidant 1010 and zinc stearate in a mass ratio of 1:2; A method for preparing an extruded flame-retardant plastic pipe includes the following steps: mixing raw materials evenly, extruding and molding to obtain an extruded flame-retardant plastic pipe.

[0023] Example 3 An extruded flame-retardant plastic pipe comprises the following raw materials in parts by weight: 100 parts polypropylene, 15 parts ethylene-octene copolymer, 4 parts glass fiber, 10 parts flame retardant, and 5 parts additives. The polypropylene is talc-filled polypropylene with a talc content of 20 wt% and the model is PP CS 2-8120. The flame retardant consists of brominated styrene and antimony trioxide in a mass ratio of 4:1; Brominated styrene consists of styrene-1 bromide and styrene-2 ​​bromide in a mass ratio of 2:2; The additives consist of antioxidant 1076 and zinc stearate in a mass ratio of 1:2; A method for preparing an extruded flame-retardant plastic pipe includes the following steps: mixing raw materials evenly, extruding and molding to obtain an extruded flame-retardant plastic pipe.

[0024] Example 4 The difference between Example 4 and Example 2 is that the brominated styrene is composed of a first brominated styrene and a second brominated styrene in a mass ratio of 2:3.

[0025] Example 5 Compared with Example 4, Example 5 differs in that the polypropylene (with a talc content of 20wt%, model PP CS 2-8120) is replaced with an equal amount of polypropylene, and the talc content is 25wt%, model PP CS 2-6130.

[0026] Example 6 Compared with Example 4, Example 6 differs in that the polypropylene (with a talc content of 20wt%, model PP CS 2-8120) is replaced with an equal amount of polypropylene, and the talc content is 10wt%, model PP CS 1-7110N.

[0027] Example 7 Compared with Example 4, Example 7 differs in that the polypropylene (with a talc filling amount of 20wt%, model PP CS 2-8120) is replaced with an equal amount of polypropylene, and the talc filling amount is 40wt%, model PP CS 2-6140RC.

[0028] Example 8 Compared with Example 4, Example 8 differs in that polypropylene (with a talc filler content of 20wt%, model PP CS 2-8120) is replaced with an equal amount of polypropylene, model PP CS 2-8000.

[0029] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the flame retardant is brominated styrene.

[0030] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the flame retardant is antimony trioxide.

[0031] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that the styrene bromide is styrene-first bromide.

[0032] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that the brominated styrene is a second brominated styrene.

[0033] Experimental Example 1 The flame retardant properties of the extruded flame retardant plastic tubes prepared in Examples 1-4 and Comparative Examples 1-4 were tested according to the test method in DIN 4102-1.

[0034] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-4 and Comparative Examples 1-4

[0035] As shown in Table 1, when the flame retardant is composed of styrene bromide and antimony trioxide, and the styrene bromide is composed of first styrene bromide and second styrene bromide with different weight average molecular weights, the flame retardant performance of extruded plastic pipes can be improved.

[0036] Experimental Example 2 The extruded flame-retardant plastic pipes prepared in Examples 4-8 were subjected to tensile strength tests according to the test methods specified in GB / T 1040.1-2018 "Determination of tensile properties of plastics - Part 1: General Rules"; the average value of 5 samples was used as the result value, and the test speed was 200 mm / min.

[0037] The test results are shown in Table 2: Table 2 Performance test results of Examples 4-8

[0038] As shown in Table 2, when polypropylene is talc-filled polypropylene and the talc content is 20wt%~25wt%, the strength of extruded flame-retardant plastic pipes can be improved.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An extruded flame-retardant plastic pipe, characterized in that, The raw materials include the following components in parts by weight: 100 parts polypropylene, 10-15 parts ethylene-octene copolymer, 2-4 parts glass fiber, 8-10 parts flame retardant, and 3-5 parts additives. The flame retardant is composed of brominated styrene and antimony trioxide in a mass ratio of 3-4:

1. The brominated styrene is composed of first brominated styrene and second brominated styrene, and the first brominated styrene and the second brominated styrene have different weight-average molecular weights.

2. The extruded flame-retardant plastic pipe according to claim 1, characterized in that, The first brominated styrene has a weight-average molecular weight of 40,000, and the second brominated styrene has a weight-average molecular weight of 150,000.

3. The extruded flame-retardant plastic pipe according to claim 2, characterized in that, The mass ratio of the first brominated styrene to the second brominated styrene is 2:2~3.

4. The extruded flame-retardant plastic pipe according to claim 1, characterized in that, The additive consists of an antioxidant and a lubricant in a mass ratio of 1:2 to 3.

5. The extruded flame-retardant plastic pipe according to claim 4, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 168.

6. The extruded flame-retardant plastic pipe according to claim 4, characterized in that, The lubricant includes one or both of polyethylene wax and zinc stearate.

7. The extruded flame-retardant plastic pipe according to claim 1, characterized in that, The polypropylene is talc-filled polypropylene, and the talc filling amount is 20wt%~25wt%.

8. The extruded flame-retardant plastic pipe according to claim 1, characterized in that, The glass fiber has a diameter of 8~12μm and a length of 3~5mm.

9. The extruded flame-retardant plastic pipe according to claim 1, characterized in that, The antimony trioxide has an α-crystal form and a particle size of 400-800 mesh.

10. A method for preparing an extruded flame-retardant plastic pipe, used to prepare the extruded flame-retardant plastic pipe according to any one of claims 1 to 9, characterized in that, The process includes the following steps: mixing the raw materials evenly and extruding them to obtain the extruded flame-retardant plastic tube.

Images