Phosphorus-nitrogen flame-retardant polypropylene and preparation method thereof

Abstract

The invention relates to phosphorus-nitrogen flame-retardant polypropylene and a preparation method thereof. The flame retardant property and the mechanical strength of polypropylene can be improved by adding a flame retardant and a reinforcing agent into polypropylene according to a specific proportion, and the phosphorus-nitrogen type flame-retardant polypropylene comprises the following components in parts by weight: 40-60 parts of polypropylene, 20-30 parts of the flame retardant, 12-18 parts of the reinforcing agent, 0.5 part of an antioxidant and 0.3 part of a dispersing agent. According to the invention, the polypropylene with high strength and high flame retardant property is obtained through the processes of burdening, mixing, melt extrusion, cooling shaping, stretching orientation and heat treatment according to the proportion. The modified polypropylene is suitable for various application scenes with high flame retardance, such as household textiles, building materials and industrial cloth, and is wide in application and suitable for popularization.

Description

Technical Field

[0001] The invention belongs to the field of flame retardant polymer materials and relates to a phosphorus-nitrogen type flame retardant polypropylene. The modified polypropylene is suitable for various application occasions requiring high flame retardancy, such as household textiles, building materials and industrial fabrics. Background Art

[0002] As one of the five general-purpose plastics, polypropylene has the advantages of low density, low cost, excellent processing performance, good electrical insulation and excellent mechanical properties, and is widely used in the fields of construction, automobiles, home appliances, etc. Although the existing polypropylene materials have excellent mechanical properties and chemical stability, the limiting oxygen index of PP is low, only 17%, which is very easy to burn. When burning, it releases a lot of heat and produces a lot of molten droplets, which can easily cause fires, causing huge losses to people's lives and property. In order to improve the flame retardant properties of polypropylene, it is usually achieved by adding flame retardants.

[0003] Flame retardants are mainly divided into halogen flame retardants and halogen-free flame retardants. Halogen flame retardants have the advantages of high flame retardant efficiency, small addition amount, and low precipitation. They are the most widely used flame retardants in the last century, but most halogen flame retardants release harmful gases when burned, so their application is limited. Halogen-free flame retardants mainly include phosphorus-nitrogen flame retardants, red phosphorus systems, intumescent flame retardants (IFR) and inorganic flame retardants.

[0004] In recent years, phosphorus-nitrogen flame retardants have become a research hotspot. Piperazine phosphate (PAPP) is a new type of phosphorus-nitrogen flame retardant. The single component of the flame retardant contains an acid source, a carbon source and a gas source, which can well solve the compatibility problem between intumescent flame retardants and polymer materials, and avoid the defects of intumescent flame retardants in polymers such as migration and frosting. PAPP can better integrate with polymer materials at the molecular level, improve the dispersion of flame retardants in materials, reduce agglomeration effects, and improve flame retardant efficiency; at the same time, PAPP is not easy to hydrolyze and is not easy to precipitate in materials, so it can be used for flame retardancy of various polymer materials. Summary of the invention

[0005] The purpose of the present invention is to provide a phosphorus-nitrogen flame-retardant polypropylene and a preparation method thereof, which can improve the flame-retardant properties of polypropylene.

[0006] The technical solution to achieve the purpose of the present invention is: a high-strength flame-retardant polypropylene, which is composed of the following components in parts by weight: 40-60 parts of polypropylene, 20-30 parts of flame retardant, 15 parts of reinforcing agent, 0.5 parts of antioxidant, and 0.3 parts of dispersant.

[0007] In a preferred embodiment of the present invention, the material for preparing the high-strength flame-retardant polypropylene is preferably composed of the following components in parts by weight: 50 parts of polypropylene, 25 parts of flame retardant, 15 parts of reinforcing agent, 0.4 parts of antioxidant, and 0.3 parts of dispersant.

[0008] Preferably, the flame retardant is focused piperazine phosphate.

[0009] Preferably, the enhancer is Changhai 832.

[0010] Preferably, the antioxidant is antioxidant 1010 and antioxidant 168.

[0011] Preferably, the dispersant is dispersant E525.

[0012] The present invention also provides a method for preparing phosphorus-nitrogen flame-retardant polypropylene, comprising the following steps:

[0013] S1. Batching: preparing a masterbatch by mixing polypropylene, flame retardant, antioxidant and dispersant in a specific ratio;

[0014] S2, mixing: the masterbatch is mixed in a high-speed mixer to obtain a mixture, the mixing speed is 300r / min, and the mixing time is 3min;

[0015] S3, melt extrusion: add the reinforcing agent from the side feeding port of the extruder, mix it with the mixed material and then melt extrude it to form a preliminary modified polypropylene. The temperature of the melt extrusion is 180-220°C;

[0016] S4, cooling and shaping: cooling the extruded modified polypropylene to room temperature and performing shaping treatment;

[0017] S5, stretching orientation: the cooled modified polypropylene is subjected to stretching orientation treatment, and the stretching ratio is 2-4 times;

[0018] S6. Heat treatment: heat-treat the stretched modified polypropylene at a temperature of 120-150° C. for 30-60 minutes.

[0019] The invention significantly improves the flame retardant property of polypropylene and takes into account the tensile property. The phosphorus-nitrogen flame retardant polypropylene is suitable for various application occasions requiring high flame retardancy, such as household textiles, building materials and industrial fabrics. DETAILED DESCRIPTION

[0020] [Example 1]

[0021] A phosphorus-nitrogen flame-retardant polypropylene, the preparation material of which consists of the following components in parts by weight:

[0022] 40 parts of polypropylene, 20 parts of flame retardant, 15 parts of reinforcing agent, 0.4 parts of antioxidant, and 0.3 parts of dispersant.

[0023] The method for making the fiber comprises the following steps:

[0024] S1. Batching: preparing a masterbatch by mixing polypropylene, flame retardant, antioxidant and dispersant in a specific ratio;

[0025] S2, mixing: the masterbatch is mixed in a high-speed mixer to obtain a mixture, the mixing speed is 300r / min, and the mixing time is 3min;

[0026] S3, melt extrusion: add the reinforcing agent from the side feeding port of the extruder, mix it with the mixed material and then melt extrude it to form a preliminary modified polypropylene. The temperature of the melt extrusion is 180-220°C;

[0027] S4, cooling and shaping: cooling the extruded modified polypropylene to room temperature and performing shaping treatment;

[0028] S5, stretching orientation: the cooled modified polypropylene is subjected to stretching orientation treatment, and the stretching ratio is 2-4 times;

[0029] S6. Heat treatment: heat-treat the stretched modified polypropylene at a temperature of 120-150° C. for 30-60 minutes.

[0030] [Example 2]

[0031] A phosphorus-nitrogen flame-retardant polypropylene, the preparation material of which consists of the following components in parts by weight:

[0032] 40 parts of polypropylene, 25 parts of flame retardant, 15 parts of reinforcing agent, 0.4 parts of antioxidant, and 0.3 parts of dispersant.

[0033] The method for making the fiber comprises the following steps:

[0034] S1. Batching: preparing a masterbatch by mixing polypropylene, flame retardant, antioxidant and dispersant in a specific ratio;

[0035] S2, mixing: the masterbatch is mixed in a high-speed mixer to obtain a mixture, the mixing speed is 300r / min, and the mixing time is 3min;

[0036] S3, melt extrusion: add the reinforcing agent from the side feeding port of the extruder, mix it with the mixed material and then melt extrude it to form a preliminary modified polypropylene. The temperature of the melt extrusion is 180-220°C;

[0037] S4, cooling and shaping: cooling the extruded modified polypropylene to room temperature and performing shaping treatment;

[0038] S5, stretching orientation: the cooled modified polypropylene is subjected to stretching orientation treatment, and the stretching ratio is 2-4 times;

[0039] S6. Heat treatment: heat-treat the stretched modified polypropylene at a temperature of 120-150° C. for 30-60 minutes.

[0040] [Example 3]

[0041] A phosphorus-nitrogen flame-retardant polypropylene, the preparation material of which consists of the following components in parts by weight:

[0042] 40 parts of polypropylene, 30 parts of flame retardant, 15 parts of reinforcing agent, 0.4 parts of antioxidant, and 0.3 parts of dispersant.

[0043] The method for making the fiber comprises the following steps:

[0044] S1. Batching: preparing a masterbatch by mixing polypropylene, flame retardant, antioxidant and dispersant in a specific ratio;

[0045] S2, mixing: the masterbatch is mixed in a high-speed mixer to obtain a mixture, the mixing speed is 300r / min, and the mixing time is 3min;

[0046] S3, melt extrusion: add the reinforcing agent from the side feeding port of the extruder, mix it with the mixed material and then melt extrude it to form a preliminary modified polypropylene. The temperature of the melt extrusion is 180-220°C;

[0047] S4, cooling and shaping: cooling the extruded modified polypropylene to room temperature and performing shaping treatment;

[0048] S5, stretching orientation: the cooled modified polypropylene is subjected to stretching orientation treatment, and the stretching ratio is 2-4 times;

[0049] S6. Heat treatment: heat-treat the stretched modified polypropylene at a temperature of 120-150° C. for 30-60 minutes.

[0050] [Example 4]

[0051] A phosphorus-nitrogen flame-retardant polypropylene, the preparation material of which consists of the following components in parts by weight:

[0052] 50 parts of polypropylene, 25 parts of flame retardant, 15 parts of reinforcing agent, 0.4 parts of antioxidant, and 0.3 parts of dispersant.

[0053] The method for making the fiber comprises the following steps:

[0054] S1. Batching: preparing a masterbatch by mixing polypropylene, flame retardant, antioxidant and dispersant in a specific ratio;

[0055] S2, mixing: the masterbatch is mixed in a high-speed mixer to obtain a mixture, the mixing speed is 300r / min, and the mixing time is 3min;

[0056] S3, melt extrusion: add the reinforcing agent from the side feeding port of the extruder, mix it with the mixed material and then melt extrude it to form a preliminary modified polypropylene. The temperature of the melt extrusion is 180-220°C;

[0057] S4, cooling and shaping: cooling the extruded modified polypropylene to room temperature and performing shaping treatment;

[0058] S5, stretching orientation: the cooled modified polypropylene is subjected to stretching orientation treatment, and the stretching ratio is 2-4 times;

[0059] S6. Heat treatment: heat-treat the stretched modified polypropylene at a temperature of 120-150° C. for 30-60 minutes.

[0060] [Example 5]

[0061] A phosphorus-nitrogen flame-retardant polypropylene, the preparation material of which consists of the following components in parts by weight:

[0062] 60 parts of polypropylene, 25 parts of flame retardant, 15 parts of reinforcing agent, 0.4 parts of antioxidant, and 0.3 parts of dispersant.

[0063] The method for making the fiber comprises the following steps:

[0064] S1. Batching: preparing a masterbatch by mixing polypropylene, flame retardant, antioxidant and dispersant in a specific ratio;

[0065] S2, mixing: the masterbatch is mixed in a high-speed mixer to obtain a mixture, the mixing speed is 300r / min, and the mixing time is 3min;

[0066] S3, melt extrusion: add the reinforcing agent from the side feeding port of the extruder, mix it with the mixed material and then melt extrude it to form a preliminary modified polypropylene. The temperature of the melt extrusion is 180-220°C;

[0067] S4, cooling and shaping: cooling the extruded modified polypropylene to room temperature and performing shaping treatment;

[0068] S5, stretching orientation: the cooled modified polypropylene is subjected to stretching orientation treatment, and the stretching ratio is 2-4 times;

[0069] S6. Heat treatment: heat-treat the stretched modified polypropylene at a temperature of 120-150° C. for 30-60 minutes.

[0070] The flame retardant properties of the present invention are tested by the oxygen index (test standard GB / T 2406-2009). If the limiting oxygen index is greater than 29%, the material has good flame retardant properties.

[0071] The tensile properties of the present invention are tested by tensile strength (test standard ISO 527-2019). If the tensile strength is greater than 34Mpa, the material has good tensile properties.

[0072] For the convenience of comparison, the experimental results are listed in Table 1.

[0073] As shown in Table 1, in Examples 1 to 5, as the amount of flame retardant PAPP increases, the limiting oxygen index also increases, up to 32.3%, but the tensile strength also decreases. Therefore, in order to balance the flame retardant performance and tensile performance, Example 4 can be preferred, with a limiting oxygen index of 30.2% and a tensile strength of 35.0Mpa.

[0074] Preferably, the phosphorus-nitrogen flame-retardant polypropylene is composed of the following components in parts by weight:

[0075] 50 parts of polypropylene, 25 parts of flame retardant, 15 parts of reinforcing agent, 0.4 parts of antioxidant, and 0.3 parts of dispersant.

[0076] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention; although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0077] Table 1

[0078]

Claims

1. A phosphorus-nitrogen flame-retardant polypropylene, characterized in that: Includes the following components: Polypropylene: 40-60 parts; Flame retardant: 20-30 parts; Enhancer: 12-18 parts; Antioxidant: 0.5 parts; Dispersant: 0.3 parts.

2. The phosphorus-nitrogen flame-retardant polypropylene according to claim 1, characterized in that: The polypropylene grade is T30S, the molecular weight is 90,000, and the tensile strength is 30-40 MPa.

3. The phosphorus-nitrogen flame-retardant polypropylene according to claim 1, characterized in that: The flame retardant is focused piperazine phosphate, and the initial decomposition temperature (T 5％ ) is 305℃, and the residual carbon rate at 800℃ is 10.4%.

4. The phosphorus-nitrogen flame-retardant polypropylene according to claim 1, characterized in that: The reinforcing agent is chopped glass fiber, the brand is Changhai 832, and the linear density is 2400-4800.

5. The phosphorus-nitrogen flame-retardant polypropylene according to claim 1, characterized in that: The antioxidant is one or a combination of antioxidant 1010 and antioxidant 168.

6. The phosphorus-nitrogen flame-retardant polypropylene according to claim 1, characterized in that: The dispersant is dispersant E525.

7. A method for preparing phosphorus-nitrogen flame-retardant polypropylene, characterized in that: The following steps are involved: S1. Batching: preparing a masterbatch by mixing polypropylene, flame retardant, antioxidant and dispersant in a specific ratio; S2, mixing: mixing the masterbatch in a high-speed mixer to obtain a mixed material; S3, melt extrusion: adding the reinforcing agent from the side feeding port of the extruder, mixing with the mixed material and then melt extruding to form a preliminary modified polypropylene; S4, cooling and shaping: cooling the preliminarily modified polypropylene to room temperature and performing shaping treatment; S5. Stretch orientation: The cooled polypropylene is subjected to stretch orientation treatment with a stretching ratio of 2-4 times; S6. Heat treatment: heat treating the stretched polypropylene.

8. The preparation method according to claim 7, characterized in that: The mixing speed is 300 r / min and the mixing time is 3 min.

9. The preparation method according to claim 7, characterized in that: The temperature of the melt extrusion is 180-220°C.

10. The preparation method according to claim 7, characterized in that: The heat treatment temperature is 120-150° C. and the time is 30-60 min.

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