Polyethylene flame-retardant master batch, its preparation method and application

Abstract

This invention relates to the field of polymer materials technology, and discloses a polyethylene flame-retardant masterbatch, its preparation method, and its applications. The polyethylene flame-retardant masterbatch comprises the following raw materials in parts by weight: 25-35 parts polyethylene resin, 60-70 parts flame retardant, 3-5 parts antioxidant, 3-5 parts UV stabilizer, and 3-5 parts lubricant; the flame retardant includes bromine-based flame retardants and antimony-based flame retardants; the antioxidant includes phosphite antioxidants and hindered phenolic antioxidants; and the UV stabilizer includes ultraviolet light absorbers and hindered amine ultraviolet stabilizers. The polyethylene flame-retardant masterbatch provided by this invention has good flame retardancy, good weather resistance, excellent processing performance, and a simple preparation method, which can meet the application requirements of chemical, agricultural, construction, packaging, or outdoor shelter products such as tents and awnings.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a polyethylene flame retardant masterbatch, its preparation method, and its application. Background Technology

[0002] Polyethylene (PE) has advantages such as being odorless, non-toxic, having excellent low-temperature resistance, good chemical stability, resistance to most acids and alkalis, low water absorption, and excellent electrical insulation. It is widely used in chemical, agricultural, construction, packaging, and outdoor covering products and other fields.

[0003] Polyethylene has an oxygen index of around 17, making it flammable. When used in outdoor shelter products (such as tents and awnings), it needs to be modified to be flame-retardant to prevent fires and other safety accidents. Furthermore, existing polyethylene-based outdoor shelter products suffer from poor weather resistance and short service life. Therefore, developing a polyethylene material with good flame retardancy and strong weather resistance to meet the application requirements of outdoor shelter products is of great significance. Summary of the Invention

[0004] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, one objective of the present invention is to provide a polyethylene flame-retardant masterbatch; a second objective is to provide a method for preparing such a polyethylene flame-retardant masterbatch; a third objective is to provide a polyethylene material; and a fourth objective is to provide applications of the polyethylene flame-retardant masterbatch or the polyethylene material.

[0005] The basic principles of this invention are explained as follows:

[0006] (1) The polyethylene flame retardant masterbatch provided by the present invention uses a compound of bromine-based flame retardant and antimony-based flame retardant as flame retardant. The bromine-antimony compound can inhibit the continuous progress of the combustion reaction chain, reduce the combustion rate, and prevent the diffusion and spread of combustion products. Based on the bromine-antimony synergistic flame retardant mechanism, the polyethylene flame retardant masterbatch has excellent flame retardant performance.

[0007] (2) The polyethylene flame retardant masterbatch provided by the present invention uses a compound of phosphite antioxidants and hindered phenolic antioxidants as antioxidants. Phosphite antioxidants have good antioxidant effect and can also provide color protection performance to prevent the polymer from yellowing or discoloring due to oxidative degradation. Hindered phenolic antioxidants can prevent the polymer material from thermal oxidative degradation during long-term aging. Mixing phosphite antioxidants and hindered phenolic antioxidants can provide excellent antioxidant effect and improve the weather resistance of the material.

[0008] (3) The polyethylene flame retardant masterbatch provided by the present invention uses a compound of ultraviolet light absorber and hindered amine ultraviolet light stabilizer as UV resist agent. The ultraviolet light absorber has a great protective effect on the polymer, which helps to reduce color change, delay yellowing and inhibit physical property loss, and can keep the physical properties of the material stable under ultraviolet light damage. The hindered amine ultraviolet light stabilizer helps to enhance the color fastness of polyolefin materials.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] The first aspect of the present invention provides a polyethylene flame retardant masterbatch, comprising the following raw materials: 25-35 parts of polyethylene resin, 60-70 parts of flame retardant, 3-5 parts of antioxidant, 3-5 parts of UV stabilizer, and 3-5 parts of lubricant.

[0011] The flame retardant includes bromine-based flame retardants and antimony-based flame retardants;

[0012] The antioxidants include phosphite antioxidants and hindered phenolic antioxidants;

[0013] The UV-resistant agent includes a UV absorber and a hindered amine UV stabilizer.

[0014] Preferably, the polyethylene flame retardant masterbatch comprises the following raw materials: 25-30 parts of polyethylene resin, 60-65 parts of flame retardant, 3-4 parts of antioxidant, 3-4 parts of UV stabilizer, and 4-5 parts of lubricant.

[0015] Preferably, the melt index of the polyethylene resin at 190℃ / 2.16kg is 15g / 10min-35g / 10min; more preferably, the melt index of the polyethylene resin at 190℃ / 2.16kg is 20g / 10min-30g / 10min. A polyethylene resin with a medium melt index (15g / 10min-35g / 10min, 190℃ / 2.16kg) is selected as the resin matrix. This type of resin has good flowability and dispersibility, which can fully coat various powders, ensuring uniform dispersion of the raw materials. Furthermore, the resin has good elongation at break and high melt strength, and will not affect the overall elongation and coating effect of the finished product during casting extrusion.

[0016] Preferably, the polyethylene resin comprises linear low-density polyethylene (LLDPE).

[0017] Preferably, the mass ratio of the bromine-based flame retardant to the antimony-based flame retardant is (2-4):1; more preferably, the mass ratio of the bromine-based flame retardant to the antimony-based flame retardant is (2.5-3.5):1.

[0018] Preferably, the brominated flame retardant includes ethylene bis(tetrabromophthalimide) (RDT-5).

[0019] Preferably, the brominated flame retardant ethylene bis(tetrabromophthalimide) (RDT-5) has a whiteness ≥88, a particle size D50 ≤5μm, and a purity ≥99%. In addition to its flame retardant properties, RDT-5 also possesses UV radiation protection properties not found in other flame retardants, simultaneously optimizing the UV resistance of polyethylene flame retardant masterbatches. Furthermore, RDT-5 has a decomposition temperature greater than 300℃, and does not decompose during masterbatch production or when used as a flame retardant masterbatch in casting extrusion.

[0020] Preferably, the antimony-based flame retardant includes at least one of antimony trioxide, antimony pentoxide, and sodium antimonate; more preferably, the antimony-based flame retardant is antimony trioxide.

[0021] Preferably, the antimony trioxide has a whiteness ≥95, a particle size D50 ≤5μm, and a purity ≥99.5%. Antimony trioxide has a decomposition temperature greater than 300℃ and does not decompose during masterbatch production or when used as a flame-retardant masterbatch in cast extrusion.

[0022] Preferably, the mass ratio of the phosphite antioxidant to the hindered phenolic antioxidant is (1-3):1; more preferably, the mass ratio of the phosphite antioxidant to the hindered phenolic antioxidant is (1.5-2.5):1.

[0023] Preferably, the phosphite antioxidant includes at least one of bis(2,4-dicumylphenyl)pentaerythritol diphosphite (antioxidant Revonox 608) and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate; more preferably, the phosphite antioxidant is Revonox 608, which has a high phosphorus content (7.3 wt%), exhibits better antioxidant effects than other similar antioxidants, and belongs to the secondary antioxidant category. Revonox 608 can quench hydrogen peroxide during auto-oxidation, thereby preventing yellowing or discoloration of the polymer due to oxidative degradation. It exhibits excellent color protection properties during mixing, which is something other phosphite antioxidants cannot achieve even when added in excess.

[0024] Preferably, the hindered phenolic antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), 2,6-di-tert-butyl-p-methylphenol (BHT), and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076); more preferably, the hindered phenolic antioxidant is antioxidant 1010. Antioxidant 1010 can effectively prevent the thermal oxidative degradation of polymer materials during long-term aging, and is also a highly efficient processing stabilizer that can improve the discoloration resistance of polymer materials under high-temperature processing conditions.

[0025] Preferably, the mass ratio of the ultraviolet light absorber to the hindered amine ultraviolet light stabilizer is (1-2):1; more preferably, the mass ratio of the ultraviolet light absorber to the hindered amine ultraviolet light stabilizer is (1-1.5):1.

[0026] Preferably, the ultraviolet light absorber includes benzophenone-based ultraviolet light absorbers; more preferably, the ultraviolet light absorber includes UV-531. UV-531 has a significant protective effect on polymers, helps reduce polymer color changes, and can also keep the physical properties of materials stable under ultraviolet light damage.

[0027] Preferably, the hindered amine UV stabilizer includes at least one of UV-119 and UV-944; more preferably, the hindered amine UV stabilizer is UV-119, which can enhance the color fastness of polyolefin materials, and UV-119 is neutral and will not react with flame retardants, thus affecting flame retardant performance.

[0028] Preferably, the thermal decomposition temperature of the lubricant is greater than 350°C.

[0029] Preferably, the lubricant comprises at least one of pentaerythritol stearate (PETS) and bio-based wax powder lubricant; the bio-based wax powder lubricant comprises Licocare RBW 102VITA wax (Clariant wax RBW102); more preferably, the lubricant is PETS. As a lubricant, PETS enables polyethylene flame retardant masterbatch to have good demolding and flow properties, ensures uniform dispersion of the flame retardant, and improves the overall flowability of the flame retardant system, making it less prone to die accumulation. In addition, PETS has outstanding thermal stability, with a thermal decomposition temperature >350℃, and is not easily decomposed during processing, thus maintaining its lubricating effect. PETS also promotes nucleation of crystalline materials, significantly improving the light transmittance and smoothness of the material.

[0030] Preferably, the lubricant pentaerythritol stearate has a melting point ≥55°C.

[0031] A second aspect of the present invention provides a method for preparing the polyethylene flame retardant masterbatch described in the first aspect of the present invention, comprising the following steps:

[0032] The raw materials are mixed, kneaded, extruded through a single screw extruder, and granulated to obtain the polyethylene flame retardant masterbatch.

[0033] Preferably, the extrusion temperature of the single-screw extruder is 140-160℃; more preferably, the extrusion temperature of the single-screw extruder is 145-155℃.

[0034] Preferably, the compression ratio of the screw is (34-38):1; more preferably, the compression ratio of the screw is (35-37):1.

[0035] In preparing polyethylene flame retardant masterbatch according to the present invention, an internal mixer is used for internal mixing, which allows the flame retardant, antioxidant and anti-UV agent to be fully melted by the rotor in the internal mixer. The shear force during the processing is small, and the flame retardant and other additives do not decompose. Then, a single screw extruder with low shear force and suitable for high fill ratio is selected for extrusion and hot cutting to obtain polyethylene flame retardant masterbatch.

[0036] A third aspect of the present invention provides a polyethylene material comprising polyethylene resin and the polyethylene flame retardant masterbatch described in the first aspect of the present invention.

[0037] Preferably, the mass ratio of the polyethylene flame retardant masterbatch to the polyethylene resin is 1:(8-12); more preferably, the mass ratio of the polyethylene flame retardant masterbatch to the polyethylene resin is 1:(9-11).

[0038] Preferably, the polyethylene resin includes at least one of high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE).

[0039] Preferably, the method for preparing the polyethylene material includes the following steps:

[0040] The polyethylene flame retardant masterbatch is mixed with polyethylene resin and then cast extrusion or injection molding is used to obtain the polyethylene material.

[0041] Preferably, the polyethylene material includes at least one of polyethylene sheets, polyethylene plates, polyethylene strips, and polyethylene films.

[0042] The fourth aspect of the present invention provides the application of the polyethylene flame retardant masterbatch described in the first aspect of the present invention, or the polyethylene material described in the third aspect of the present invention, in the fields of chemical industry, agriculture, construction, packaging, or in the preparation of outdoor protective products.

[0043] Preferably, the outdoor shelter products include tents and awnings.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] 1) The polyethylene flame retardant masterbatch provided by the present invention has excellent flame retardant properties. The polyethylene sheet prepared by compounding it with polyethylene resin has flame retardant properties that meet the CPAI-84:1995 flame retardant standard, with short flame delay time and good self-extinguishing properties.

[0046] 2) The polyethylene flame retardant masterbatch provided by this invention has good weather resistance. The polyethylene square plate prepared by compounding with polyethylene resin is tested according to the ASTM G154 Cyclel standard. The color difference value ΔE after 1000h of UV irradiation is less than 3.0. The polyethylene specimen prepared by compounding with polyethylene resin is tested according to the standard ASTM D638-2019. The tensile strength retention rate before and after UV irradiation is ≥90%. The material has good color and physical property stability.

[0047] 3) The polyethylene flame retardant masterbatch provided by the present invention has excellent processing performance. When it is compounded with polyethylene resin and cast extruded to form polyethylene film, no die accumulation or holes are generated during continuous production for 24 hours.

[0048] 4) The polyethylene flame retardant masterbatch provided by the present invention has a simple preparation method, mild process conditions, is easy to achieve large-scale production, and has high product quality and good quality stability.

[0049] 5) The polyethylene flame retardant masterbatch and polyethylene material provided by this invention have both flame retardancy and weather resistance, and can meet the application requirements of chemical, agricultural, construction, packaging, or outdoor shelter products such as tents and awnings. Detailed Implementation

[0050] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0051] Table 1. Raw material information for the preparation of polyethylene flame retardant masterbatch in the examples and comparative examples.

[0052]

[0053] Among them, RDT-5 has a whiteness ≥88, particle size D50≤5μm, and purity ≥99%; antimony trioxide has a whiteness ≥95, particle size D50≤5μm, and purity ≥99.5%; and the lubricant pentaerythritol stearate has a melting point ≥55℃.

[0054] Note: Unless otherwise specified, "parts" in the following examples and comparative examples refer to "parts by mass"; unless otherwise specified, the ratio between the compound components in the flame retardant, antioxidant and anti-UV agent refers to "mass ratio".

[0055] Example 1

[0056] This embodiment provides a polyethylene flame retardant masterbatch, and the raw materials for its preparation are shown in Table 2, wherein:

[0057] Flame retardant: RDT-5: Antimony trioxide = 2.5:1;

[0058] Antioxidant ratio: Revonox 608: Antioxidant 1010 = 2:1;

[0059] UV protectant: UV-531:UV-119 = 1:1.

[0060] Table 2 Raw materials for the preparation of polyethylene flame retardant masterbatch in Example 1

[0061]

[0062] The preparation method of polyethylene flame retardant masterbatch is as follows:

[0063] Polyethylene resin, flame retardant, antioxidant, UV stabilizer and lubricant are mixed evenly in a mixing tank and then internally mixed in an internal mixer. The mixture is then extruded in a single-screw extruder (extrusion temperature 150℃, screw compression ratio 36:1), cut into granules by a hot cutter, and fed into a large mixing tank through a fan and conveying pipeline to obtain polyethylene flame retardant masterbatch.

[0064] Example 2

[0065] This embodiment provides a polyethylene flame retardant masterbatch, and the raw materials for its preparation are shown in Table 3, wherein:

[0066] Flame retardant: RDT-5: Antimony trioxide = 3.5:1;

[0067] Antioxidant ratio: Revonox 608: Antioxidant 1010 = 2:1;

[0068] UV protectant: UV-531:UV-119 = 1:1.

[0069] Table 3 Raw materials for the preparation of polyethylene flame retardant masterbatch in Example 2

[0070]

[0071]

[0072] The preparation method of polyethylene flame retardant masterbatch is as follows:

[0073] Polyethylene resin, flame retardant, antioxidant, UV stabilizer and lubricant are mixed evenly in a mixing tank and then internally mixed in an internal mixer. The mixture is then extruded in a single-screw extruder (extrusion temperature 150℃, screw compression ratio 36:1), cut into granules by a hot cutter, and fed into a large mixing tank through a fan and conveying pipeline to obtain polyethylene flame retardant masterbatch.

[0074] Comparative Example 1

[0075] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that the amount of flame retardant is reduced to 55 parts and the amount of polyethylene resin is increased to 35 parts. The preparation process is the same as in Examples 1-2.

[0076] Comparative Example 2

[0077] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that the flame retardant RDT-5:antimony trioxide = 2.5:1 is replaced with decabromodiphenyl ethane:antimony trioxide = 2.5:1. The preparation process is the same as in Examples 1-2.

[0078] Comparative Example 3

[0079] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 2 only in that the ratio of RDT-5:antimony trioxide = 3.5:1 is changed to octabromoether:antimony trioxide = 3.5:1. The preparation process is the same as in Examples 1-2.

[0080] Comparative Example 4

[0081] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 2 only in that the ratio of RDT-5:antimony trioxide = 3.5:1 is changed to RDT-5:antimony trioxide = 1:1. The preparation process is the same as in Examples 1-2.

[0082] Comparative Example 5

[0083] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that the ratio of RDT-5:antimony trioxide = 2.5:1 is changed to RDT-55:antimony trioxide = 4.5:1. The preparation process is the same as in Examples 1-2.

[0084] Comparative Example 6

[0085] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that 3 parts Revonox 608: antioxidant 1010 = 2:1 are replaced with 1 part Revonox 608: antioxidant 1010 = 2:1. The preparation process is the same as in Examples 1-2.

[0086] Comparative Example 7

[0087] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 2 only in that 3 parts Revonox 608: antioxidant 1010 = 2:1 is replaced with 3 parts antioxidant 168: antioxidant 1010 = 2:1. The preparation process is the same as in Examples 1-2.

[0088] Comparative Example 8

[0089] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 2 only in that 3 parts UV-531:UV-119 = 1:1 are changed to 1 part UV-531:UV-119 = 1:1. The preparation process is the same as in Examples 1-2.

[0090] Comparative Example 9

[0091] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that 3 parts UV-531:UV-119 = 1:1 is replaced with 3 parts UV-531. The preparation process is the same as in Examples 1-2.

[0092] Comparative Example 10

[0093] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that 3 parts UV-531:UV-119 = 1:1 is replaced with 3 parts UV-119. The preparation process is the same as in Examples 1-2.

[0094] Comparative Example 11

[0095] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 2 only in that 4 parts of lubricant PETS are replaced with 4 parts of lubricant EBS. The preparation process is the same as in Examples 1-2.

[0096] Comparative Example 12

[0097] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that, during the preparation process, the raw materials polyethylene resin, flame retardant, antioxidant, UV stabilizer, and lubricant are mixed evenly in a mixing tank and then added to a twin-screw extruder for extrusion granulation to form polyethylene flame retardant masterbatch.

[0098] Comparative Example 13

[0099] This comparative example provides a polyethylene flame retardant masterbatch, which differs from Example 1 only in that 30 parts of LLDPE M2320 are replaced with 30 parts of LLDPE 7042. The preparation process is the same as in Examples 1-2.

[0100] Performance testing

[0101] 1. Flame retardant performance test

[0102] The polyethylene flame retardant masterbatch prepared in Example 1 and Comparative Examples 1, 2, 5, 6, 9, 10, 12, and 13 was mixed with polyethylene resin LDPE 2420H (CNOOC Shell, MI 2 g / 10 min, tensile strength 15 MPa) at a mass ratio of 1:10 and then extruded into 0.5 mm thin sheets in a casting machine with a screw diameter of 35 mm.

[0103] The polyethylene flame retardant masterbatch prepared in Example 2 and Comparative Examples 3, 4, 7, 8 and 11 was mixed with polyethylene resin HDPEF120A (Hanwha Total, MI of 0.04 g / 10 min, tensile strength of 22 MPa) at a mass ratio of 1:10 and then extruded into 0.5 mm thin sheets in a casting machine with a screw diameter of 35 mm.

[0104] The obtained thin film was prepared and tested according to the standard CPAI-84:1995 Tent Flame Retardant Test. The test results are shown in Table 4.

[0105] 2. UV resistance test

[0106] The polyethylene flame retardant masterbatch prepared in Example 1 and Comparative Examples 1, 2, 5, 6, 9, 10, 12, and 13 was mixed with polyethylene resin LDPE 2420H (CNOOC Shell, MI 2 g / 10 min, tensile strength 15 MPa) at a mass ratio of 1:10 and then injection molded into square plates of 10 mm * 10 mm * 3 mm (±0.5 mm) using an injection molding machine.

[0107] The polyethylene flame retardant masterbatch prepared in Example 2 and Comparative Examples 3, 4, 7, 8 and 11 was mixed with polyethylene resin HDPEF120A (Hanwha Total, MI is 0.04 g / 10 min, tensile strength is 22 MPa) at a mass ratio of 1:10 and then injection molded into square plates of 10 mm * 10 mm * 3 mm (±0.5 mm) in an injection molding machine.

[0108] The color difference value ΔE of the square plate was tested for 1000 hours according to the test standard of ASTM G154 Cycle1. The test results are shown in Table 5.

[0109] 3. Tensile strength retention rate test

[0110] The polyethylene flame retardant masterbatch prepared in Example 1 and Comparative Examples 1, 2, 5, 6, 9, 10, 12, and 13 was mixed with polyethylene resin LDPE 2420H (CNOOC Shell, MI 2 g / 10 min, tensile strength 15 MPa) at a mass ratio of 1:10 and then injection molded into a sample strip with a thickness of 3.2 mm in an injection molding machine.

[0111] The polyethylene flame retardant masterbatch prepared in Example 2 and Comparative Examples 3, 4, 7, 8 and 11 was mixed with polyethylene resin HDPEF120A (Hanwha Total, MI of 0.04 g / 10 min, tensile strength of 22 MPa) at a mass ratio of 1:10 and then injection molded into a sample strip with a thickness of 3.2 mm in an injection molding machine.

[0112] The tensile strength before and after UV irradiation was tested according to the standard ASTM D638-2019. The tensile strength retention rate was calculated as follows: tensile strength retention rate = tensile strength after UV irradiation / tensile strength before UV irradiation * 100%. The test results are shown in Table 6.

[0113] 4. Test for material accumulation in the die.

[0114] The polyethylene flame retardant masterbatches prepared in Example 1 and Comparative Examples 1, 2, 5, 6, 9, 10, 12, and 13 were mixed with polyethylene resin LDPE 2420H (CNOOC Shell, MI 2 g / 10 min, tensile strength 15 MPa) at a mass ratio of 1:10. The accumulation of material at the bottom of the die was observed when the mixture was extruded and cast into a tent outer film in a casting machine, and the time when a hole was formed was recorded.

[0115] The polyethylene flame-retardant masterbatches prepared in Example 2 and Comparative Examples 3, 4, 7, 8, and 11 were mixed with polyethylene resin HDPEF120A (Hanwha Total, MI 0.04 g / 10 min, tensile strength 22 MPa) at a mass ratio of 1:10. The accumulation of material at the lower end of the die was observed when the mixture was extruded into a tent outer film in a casting machine, and the time when a hole appeared was recorded. The test results are shown in Table 7.

[0116] Table 4 Flame retardant performance test results

[0117]

[0118]

[0119] Table 5. UV resistance performance test results

[0120] serial number Color difference value ΔE after 1000 hours of UV irradiation serial number Color difference value ΔE after 1000 hours of UV irradiation Example 1 2.75 Comparative Example 7 3.80 Example 2 2.90 Comparative Example 8 5.80 Comparative Example 1 2.87 Comparative Example 9 5.10 Comparative Example 2 4.50 Comparative Example 10 3.10 Comparative Example 3 8.90 Comparative Example 11 3.30 Comparative Example 4 2.70 Comparative Example 12 / Comparative Example 5 3.25 Comparative Example 13 3.50 Comparative Example 6 4.30

[0121] Table 6. Results of Tensile Strength Retention Rate Test

[0122]

[0123]

[0124] Table 7 Test Results of Die-Stage Material Layout

[0125] serial number Material accumulation at the bottom of the die after 24 hours of continuous production Time to generate holes during continuous production for 24 hours Example 1 No obvious material accumulation No holes were found Example 2 No obvious material accumulation No holes were found Comparative Example 1 No obvious material accumulation No holes were found Comparative Example 2 Material accumulation began after 1 hour. Holes began to appear after 2 hours. Comparative Example 3 Severe burning of die material Too many holes, unable to produce normally. Comparative Example 4 No obvious material accumulation Holes began to appear 14 hours later. Comparative Example 5 No obvious material accumulation No holes were found Comparative Example 6 Material accumulation began to occur 3 hours after production. Holes began to appear 5 hours later. Comparative Example 7 Material accumulation began to occur after 6 hours of production. Holes began to appear 8 hours later. Comparative Example 8 No obvious material accumulation No holes were found Comparative Example 9 No obvious material accumulation No holes were found Comparative Example 10 No obvious material accumulation No holes were found Comparative Example 11 Material accumulation began to occur 12 hours after production. Holes began to appear 13 hours later. Comparative Example 12 / / Comparative Example 13 Material accumulation began to occur after 6 hours of production. Holes began to appear 7 hours later.

[0126] Table 4 shows the flame retardant performance test results, Table 5 shows the UV resistance test results, Table 6 shows the tensile strength retention rate test results, and Table 7 shows the die material accumulation test results. From Tables 4-7, we can see that:

[0127] (1) In Examples 1 and 2, the polyethylene flame retardant masterbatch obtained by mixing and kneading medium melt index (20g / 10min, 190℃ / 2.16kg), good fluidity and dispersibility LLDPE M2320, RDT-5 with a mass ratio of (2.5-3.5):1, antimony trioxide compound flame retardant, antioxidant Revonox 608 with a mass ratio of (1.5-2.5):1, antioxidant 1010, UV absorber UV-531 with a mass ratio of (1-1.5):1, hindered amine UV stabilizer UV-119, and PETS lubricant as raw materials, and extruding with a single screw extruder, has excellent flame retardant properties. After being diluted proportionally, it can pass the flame retardant performance test of CPAI-84:1995. The material has a short flame delay time and good self-extinguishing properties. Based on the combined effect of antioxidants and UV stabilizers, the material meets the requirements of ASTM G154. The color difference value ΔE measured by the Cycle1 test standard after 1000 hours of UV irradiation remained within the range of 2.75-2.90, indicating a small color difference. Furthermore, the tensile strength retention rate before and after UV irradiation was ≥90.0%, meaning that the material's color and physical properties showed minimal change. The polyethylene flame-retardant masterbatch provides excellent weather resistance. During extrusion casting, no significant material accumulation or holes were observed at the bottom of the die after 24 hours of continuous production, demonstrating good processing performance. Therefore, ensuring that the types and proportions of raw materials used in the preparation of the polyethylene flame-retardant masterbatch are within the scope provided by this invention enables polyethylene materials containing both polyethylene flame-retardant masterbatch and polyethylene resin to possess excellent flame retardancy, weather resistance, and processing performance, meeting the application requirements of outdoor shading products and other fields.

[0128] (2) The only difference between Comparative Example 1 and Example 1 is that the amount of flame retardant is reduced. However, the flame retardant masterbatch in Comparative Example 1 has a flame delay time of more than 4 seconds for the polyethylene sheet, and the flame retardant performance test is unqualified. Furthermore, the tensile strength retention rate of the corresponding sample is reduced after UV irradiation.

[0129] (3) The only difference between Comparative Example 2 and Example 1 is that decabromodiphenyl ethane is used instead of RDT-5, and the only difference between Comparative Example 3 and Example 2 is that octabromoether is used instead of RDT-5. In Comparative Example 2, the color difference ΔE of the polyethylene square plate corresponding to the flame retardant masterbatch increased to 4.50 after 1000h of UV irradiation, and the tensile strength retention rate of the polyethylene sample before and after UV irradiation decreased to 69.2%. During the continuous production of polyethylene film by extrusion casting, material accumulation began to appear after 1h of continuous production, and holes began to appear after 2h. In Comparative Example 3, the color difference ΔE of the polyethylene square plate corresponding to the flame retardant masterbatch increased to 8.90 after 1000h of UV irradiation, and the tensile strength retention rate of the polyethylene sample before and after UV irradiation decreased to 72.2%. During the continuous production of polyethylene film by extrusion casting, the die was severely charred and had many holes, making normal production impossible. This indicates that the dispersibility of decabromodiphenyl ethane and octabromoether is not as good as that of RDT-5, which can easily lead to a decrease in flame retardant performance. Furthermore, the heat resistance of both is also lower than that of RDT-5. During casting and extrusion, the flame retardant is more likely to decompose, resulting in holes. Among them, octabromoether has the worst heat resistance and produces material accumulation and holes in a shorter time.

[0130] (4) The only difference between Comparative Example 5 and Example 1 is that the mass ratio of flame retardant RDT-5 to antimony trioxide was changed from 2.5:1 to 4.5:1. The only difference between Comparative Example 4 and Example 2 is that the mass ratio of flame retardant RDT-5 to antimony trioxide was changed from 3.5:1 to 1:1. The mass ratios of the flame retardants in both examples are outside the range provided by this invention. In Comparative Example 5, the burning length of the polyethylene sheet corresponding to the flame retardant masterbatch exceeded the standard, and in Comparative Example 4, the flame retardant time of the polyethylene sheet corresponding to the flame retardant masterbatch exceeded 4 seconds. The flame retardant performance test results were all unqualified. In addition, the tensile strength retention rates of the polyethylene samples corresponding to the flame retardant masterbatch in Comparative Example 5 and Comparative Example 4 before and after ultraviolet irradiation decreased to 85.7% and 72.2%, respectively. Furthermore, when the flame retardant masterbatch in Comparative Example 4 was used in the production of polyethylene film, holes began to appear after 14 hours of continuous extrusion casting. This indicates that when the mass ratio of RDT-5 to antimony trioxide is outside the range provided by this invention, the bromine-antimony ratio is unbalanced, the flame retardant efficiency is reduced, and the antimony trioxide ratio increases, making it easy to generate agglomeration, resulting in large white spots during casting and extrusion, and easily causing holes after stretching.

[0131] (5) The only difference between Comparative Example 6 and Example 1 is the reduction in the amount of antioxidant. The only difference between Comparative Example 7 and Example 2 is the replacement of antioxidant Revonox 608 with antioxidant 168. It can be seen that the color difference ΔE of the polyethylene square plates corresponding to the flame retardant masterbatch in Comparative Examples 6 and 7 after UV irradiation for 1000h both increased. The tensile strength retention rate of the corresponding samples before and after UV irradiation both decreased. When the flame retardant masterbatch in Comparative Example 6 was used for polyethylene film production, material accumulation began to appear after 3 hours of continuous extrusion casting production, and holes began to appear after 5 hours. When the flame retardant masterbatch in Comparative Example 7 was used for film production, material accumulation began to appear after 6 hours, and holes began to appear after 8 hours. This indicates that insufficient antioxidant or failure to use antioxidant Revonox 608 with a high phosphorus content will lead to poor weather resistance of the flame retardant masterbatch. Furthermore, the reduced proportion of high-temperature antioxidant Revonox 608 weakens the ability to extract free radicals generated during high-temperature processing, thereby weakening the processing protection effect and making it easier to accumulate material and cause holes.

[0132] (6) The only difference between Comparative Example 9 and Example 1 is the absence of the hindered amine UV stabilizer UV-119; the only difference between Comparative Example 10 and Example 1 is the absence of the UV absorber UV-531; and the only difference between Comparative Example 8 and Example 2 is the reduction in the amount of UV stabilizer. It is evident that, compared to Examples 1 and 2, changing the amount or type of the compounded UV stabilizer will prevent the full utilization of the synergistic effect of UV-531 (physical property protection) and UV-119 (color protection), resulting in a decrease in the material's weather resistance.

[0133] (7) The only difference between Comparative Example 11 and Example 2 is that EBS is used instead of PETS as a lubricant. Since EBS has poorer dispersibility and heat resistance than PETS, when the flame retardant masterbatch in Comparative Example 11 is used in the production of polyethylene film, material accumulation begins to appear after 12 hours of continuous extrusion casting, and holes begin to appear after 13 hours, resulting in poor processing performance.

[0134] (8) The only difference between Comparative Example 12 and Example 1 is that the raw materials were not mixed and kneaded during the preparation process and were extruded and granulated using a twin-screw extruder. Since the twin-screw extruder is not suitable for the production of high filling ratios, the masterbatch production process was not smooth, the material strips were brittle and could not be drawn smoothly.

[0135] (9) The only difference between Comparative Example 13 and Example 1 is that LLDPE 7042 polyethylene resin is used instead of LLDPE M2320 polyethylene resin. LLDPE 7042 has poor flowability and poor dispersion of flame retardant, which causes the flame retardant masterbatch in Comparative Example 13 to have a flame delay time of more than 4 seconds. The flame retardant performance of the flame retardant masterbatch decreases. When used in the production of polyethylene film, material accumulation begins to appear after 6 hours of continuous extrusion casting, and holes begin to appear after 7 hours, resulting in poor processing performance.

[0136] The polyethylene flame retardant masterbatch provided by this invention uses linear low-density polyethylene with a medium melt index (15g / 10min-35g / 10min, 190℃ / 2.16kg) as the resin matrix, adds a compound flame retardant with a balanced ratio of bromine and antimony, and then adds an appropriate proportion of antioxidant, UV inhibitor and high-temperature lubricant. After being internally mixed in a mixer, it is extruded and hot-cut into granules by a single screw. Based on the mutual coordination of raw material components, ratios and process conditions, the polyethylene flame retardant masterbatch has excellent flame retardancy, weather resistance and good processing performance. This allows the polyethylene material containing the polyethylene flame retardant masterbatch to also have flame retardancy and weather resistance, which can meet the application requirements of outdoor shading products and other fields.

Claims

1. A polyethylene flame retardant masterbatch, characterized by, By weight, it includes the following raw materials: 25-35 parts polyethylene resin, 60-70 parts flame retardant, 3-5 parts antioxidant, 3-5 parts UV stabilizer, and 3-5 parts lubricant. The polyethylene resin is LLDPE M2320; The flame retardant is a compound of bromine-based flame retardant and antimony-based flame retardant in a mass ratio of (2-4):1, wherein the bromine-based flame retardant is ethylene bis(tetrabromophthalimide) and the antimony-based flame retardant is antimony trioxide. The antioxidant is a compound of phosphite antioxidant and hindered phenolic antioxidant in a mass ratio of (1-3):1, wherein the phosphite antioxidant is bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, and the hindered phenolic antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester; The UV stabilizer is a compound of a UV absorber and a hindered amine UV stabilizer in a mass ratio of (1-2):1, wherein the UV absorber is UV-531 and the hindered amine UV stabilizer is UV-119. The lubricant is selected from pentaerythritol stearate; The polyethylene flame retardant masterbatch is prepared by a method comprising the following steps: The raw materials are mixed, kneaded, extruded through a single screw extruder, and granulated to obtain the polyethylene flame retardant masterbatch.

2. A polyethylene material, characterized by, It includes polyethylene resin and the polyethylene flame retardant masterbatch as described in claim 1.

3. The polyethylene material of claim 2, wherein, The mass ratio of the polyethylene flame retardant masterbatch to the polyethylene resin is 1:(8-12).

4. The application of the polyethylene flame retardant masterbatch of claim 1, or the polyethylene material of claim 2 or 3, in the fields of chemical industry, agriculture, construction, packaging, or in the preparation of outdoor protective products.

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