A UV-resistant polypropylene cable tie

Abstract

The invention discloses an anti-ultraviolet polypropylene cable tie, which is made by injection molding a polypropylene composition; the polypropylene composition comprises: a polypropylene material, a composite ultraviolet absorber, a toughening agent, a lubricant, a nucleating agent and an antioxidant; the composite ultraviolet absorber is at least two selected from the group consisting of benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers and amino ultraviolet absorbers; the lubricant is composed of montan wax, or montan wax, an ester lubricant G16, and one or more selected from the group consisting of amide lubricants, hydrocarbon lubricants and C8-30 alcohol lubricants. The invention achieves excellent anti-ultraviolet performance without reducing the transparency of the cable tie, improves the fluidity of the polypropylene composition relative to a mold, enables the polypropylene composition to quickly fill the mold within a limited space and time, and is conducive to the production of thin-walled polypropylene cable ties with a high aspect ratio.

Description

[0001] This invention is a divisional application of the Chinese invention patent application with the application date of December 2, 2020, application number 2020113901497, and name “A thin-walled, high-aspect-ratio polypropylene cable tie that is resistant to UV rays and high and low temperature impacts”. Technical Field

[0002] The invention belongs to the field of polymer materials and processing technology, in particular to a thin-walled plastic product with a high aspect ratio, and specifically to an anti-ultraviolet polypropylene cable tie. Background Art

[0003] Thin-wall plastic molding technology is a relative concept. The industry defines it in three ways: (1) The ratio of flow length to thickness, L / T, is defined as the ratio of the flow length L from the time the melt enters the mold to the farthest point of the cavity that the melt must fill to the corresponding average wall thickness T, which is 100 or 150 or more. This is thin-wall high aspect ratio injection molding; (2) The thickness of the molded plastic part is less than 1mm, and the projected area of ​​the plastic part is less than 50cm. 2 The above injection molding methods; (3) injection molding in which the wall thickness of the molded plastic part is less than 1 mm (or 1.5 mm), or t / d (plastic part thickness t, plastic part diameter d, for disc-shaped plastic parts) is less than 0.05 is defined as thin-wall injection molding.

[0004] Currently, domestic thin-wall plastic molding technology used in food containers, medicine boxes, cosmetics, stationery, and other fields falls under the category of thin-wall, low aspect ratio injection molding. Thin-wall, high aspect ratio injection molding places higher demands not only on the equipment and process, but also on the fluidity of the raw materials. Thin-wall, low aspect ratio injection molding, on the other hand, places lower fluidity requirements. A typical example of thin-wall, high aspect ratio plastic product manufacturing is cable ties with thin walls and high aspect ratios.

[0005] Polypropylene is a pure carbon chain polymer that contains neither polar groups nor chemically active groups. It has many excellent properties, such as light weight, good strength, good wear resistance, corrosion resistance, and non-hygroscopicity. This makes polypropylene products increasingly widely used in production and life. For example, thin-walled cable ties with high aspect ratios are currently most widely used with nylon 6 or nylon 66 cable ties, because nylon 6 or nylon 66 has better strength and weather resistance. However, the cost of nylon 6 or nylon 66 is relatively high, and both have a certain degree of hygroscopicity (the saturated water absorption rate of nylon 66 at room temperature reaches 4.6%, and the saturated water absorption rate of nylon 6 exceeds 8%, and as As the temperature rises, the performance of the product caused by nylon water absorption is extremely deteriorated), and the mechanical properties of the product are significantly affected by the relative humidity of the environment, while polypropylene is not hygroscopic (the saturated water absorption rate of polypropylene is less than 0.4%, and the product performance is almost unaffected by the ambient humidity and temperature (within the applicable temperature range)). In some specific application fields, polypropylene has more advantages than nylon products; on the other hand, the price of polypropylene is lower than that of nylon, the supply is less affected by the market environment, and the price is stable, which has significant advantages in the civilian field. Therefore, if polypropylene cable ties are made of polypropylene material, it is expected to partially replace the application of nylon 6 or nylon 66 cable ties in some fields.

[0006] However, in terms of chemical structure, polypropylene segments contain a large number of tertiary carbon atoms. Under illumination conditions, particularly ultraviolet radiation, polypropylene is susceptible to photooxidative degradation, resulting in polymer segment breakage and poor mechanical properties. Research by Qian Xin et al. (Flame Retardant Materials and Technology, Issue 2, 2006) shows that polypropylene was placed in a test chamber with a 320W fluorescent UV lamp, a UV wavelength of 280 to 400nm, and a chamber temperature of 60°C. Polypropylene samples were irradiated every four hours for 4 hours. After 250 hours of testing, the tensile strength of polypropylene decreased from an initial 35.6MPa to 31.4MPa. Research by Yu Jianying et al. (Journal of Materials Research, Vol. 13, No. 5) shows that after ultraviolet radiation, polypropylene undergoes rapid photooxidation. After 24 hours of irradiation, the oxidized carbon atoms on the interface account for 15.96% of the total carbon atoms. After 72 and 120 hours of irradiation, the oxidized carbon atoms reached 31.22% and 50.58%, respectively. After 24 hours of irradiation, the oxygen-containing groups introduced are primarily single-bonded oxygen (CO-C, C-OH). As irradiation time increases, the proportion of double-bonded oxygen in the form of carbonyl and carboxyl groups increases significantly. Cable ties are inevitably exposed to various operating conditions during use. For example, when used outdoors, they are exposed to ultraviolet radiation. As mentioned above, due to the special structure of existing polypropylene plastics, the UV resistance and mechanical properties do not meet the requirements of these special situations, resulting in unstable product quality, which in turn affects the performance of cable ties made of polypropylene.

[0007] At present, in the existing technology, although the UV resistance of polypropylene can be improved by adding zinc oxide, carbon black or similar milky white fillers, the addition of these substances will cause the transparency of polypropylene to be lost, and downstream customers have certain requirements for the transparency of products; at the same time, for harsh environments, such as areas with large temperature differences, cable ties are also required to have high and low temperature impact resistance, and current general-purpose polypropylene plastics are difficult to meet this requirement. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome one or more deficiencies in the prior art and provide an improved thin-walled high aspect ratio polypropylene cable tie that can significantly improve the UV resistance without reducing the transparency of the product.

[0009] For purposes of this disclosure, thin-walled refers to a wall thickness less than 1.5 mm, or a t / d ratio (part thickness t, part diameter d, for disc-shaped parts) of less than 0.05. A high aspect ratio refers to a flow length to thickness ratio (L / T), meaning that the ratio of the flow length (L) from the point where the melt enters the mold to the furthest point in the cavity that the melt must fill to the corresponding average wall thickness (T) is greater than 100. Specifically, this refers to a product length to thickness ratio of greater than 100.

[0010] In the present invention, the melt index is measured at a temperature of 230° C. and a load of 2.16 kg (measured in accordance with the national standard: GB / T3682-2000).

[0011] In the present invention, the melting peak temperature, melting enthalpy, crystallization peak temperature and crystallization enthalpy are measured by differential scanning calorimetry (DSC).

[0012] In order to solve the above technical problems, a technical solution adopted by the present invention is as follows:

[0013] An anti-ultraviolet polypropylene cable tie, which is made by injection molding a polypropylene composition;

[0014] The polypropylene composition comprises the following components in terms of mass percentage: 90-98.5% of polypropylene material, 0.1-2.5% of composite ultraviolet absorber, 1-8% of toughening agent, 0.2-1% of lubricant, 0.01-1% of nucleating agent and 0.01-0.5% of antioxidant;

[0015] The composite ultraviolet absorber is at least two selected from benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers and amino ultraviolet absorbers;

[0016] The lubricant is composed of an ester lubricant and one or more lubricants selected from amide lubricants, hydrocarbon lubricants, and C8-30 alcohol lubricants;

[0017] The ester lubricant is montan wax, or is composed of montan wax and ester lubricant G16;

[0018] The hydrocarbon lubricant is a low-density polyethylene compound SA13-9 and / or polyethylene wax, the amide lubricant is a combination of one or more selected from N,N'-diethylenebisstearamide, oleamide and amide wax, and the C8-30 alcohol lubricant is stearyl alcohol.

[0019] In some embodiments of the present invention, the ester lubricant accounts for 20-80% by mass of the lubricant, and further 20-60% by mass.

[0020] In some embodiments of the present invention, the lubricant is composed of montan wax and stearyl alcohol, or montan wax, ester lubricant G16 and stearyl alcohol, or montan wax, ester lubricant G16 and polyethylene wax, or montan wax and N,N'-diethylenebisstearamide.

[0021] In some embodiments of the present invention, the injection molding temperature is 150-225°C.

[0022] In some embodiments of the present invention, the composite ultraviolet absorber is composed of 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole and poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]}, or poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4- [(2,2,6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]} and 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, or 2-hydroxy-4-n-octyloxybenzophenone and 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole, or 2-hydroxy-4-n-octyloxybenzophenone and 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole.

[0023] In some embodiments of the present invention, the toughening agent is composed of butadiene rubber and styrene-butadiene-styrene block copolymer, or is composed of butadiene rubber and octene-ethylene copolymer, or is composed of styrene-butadiene-styrene block copolymer and ethylene propylene diene rubber, or is composed of ethylene propylene diene rubber and octene-ethylene copolymer.

[0024] Another technical solution provided by the present invention is a thin-walled, high-aspect-ratio polypropylene cable tie that is resistant to ultraviolet rays and high and low temperature impacts, which is made of a polypropylene composition, the polypropylene composition comprising the following components: a polypropylene material, a lubricant, a nucleating agent, and an antioxidant, the polypropylene composition further comprising a composite ultraviolet absorber and a toughening agent, the composite ultraviolet absorber being at least two selected from benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and amino ultraviolet absorbers; the polypropylene material has a melting peak temperature of 155-170°C, a melting enthalpy of 60-100 J / g, a crystallization peak temperature of 110-135°C, and a crystallization enthalpy of 70-105 J / g; in terms of mass percentage, the components of the polypropylene composition include 90-98.5% of polypropylene material, 0.1-2.5% of composite ultraviolet absorber, 1-8% of toughening agent, 0.2-1% of lubricant, 0.01-1% of nucleating agent, and 0.01-0.5% of antioxidant.

[0025] According to some preferred and specific aspects of the present invention, the benzophenone ultraviolet absorber is a combination of one or more selected from (2,4-dihydroxyphenyl)phenyl ketone, 2-hydroxy-4-n-octyloxybenzophenone and (2-hydroxy-4-methoxyphenyl)phenyl ketone.

[0026] According to some preferred and specific aspects of the present invention, the benzotriazole ultraviolet absorber is a combination of one or more selected from 2-(2'-hydroxy-3', 5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3', 5'bis(a,a-dimethylbenzyl)phenyl)benzotriazole, bis(3-benzotriazolyl-2-hydroxy-5-tert-octylphenyl)methane, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole.

[0027] According to some preferred and specific aspects of the present invention, the amino ultraviolet absorber is poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]}.

[0028] According to some preferred aspects of the present invention, the toughening agent is composed of a rubber toughening agent and a conventional polyolefin toughening agent. This specific combination of toughening agents can greatly improve the high and low temperature impact resistance of the polypropylene cable tie.

[0029] According to some preferred aspects of the present invention, the mass ratio of the rubber toughening agent to the conventional polyolefin toughening agent is 1:0.2-5.

[0030] According to some preferred and specific aspects of the present invention, the rubber toughening agent is a combination of one or more selected from polypropylene-acrylimide grafted copolymer, maleic anhydride grafted polypropylene, low-density polyethylene, linear low-density polyethylene, maleic anhydride grafted polyethylene, ethylene-vinyl acetate copolymer, maleic anhydride grafted ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene propylene diene monomer rubber, ethylene propylene diene monomer rubber, butadiene rubber and isobutylene rubber.

[0031] According to some preferred and specific aspects of the present invention, the conventional polyolefin toughening agent is a combination of one or more selected from octene-ethylene copolymer, styrene-butadiene-styrene block copolymer and polyethylene.

[0032] According to the present invention, the melt index of the polypropylene material is 5-100 g / 10 min, preferably 20-70 g / 10 min.

[0033] According to the present invention, the polypropylene material is a combination of one or more selected from isotactic homopolypropylene, syndiotactic homopolypropylene, random homopolypropylene, block copolymer polypropylene with an ethylene content of 7-15%, and random copolymer polypropylene.

[0034] According to some preferred aspects of the present invention, the lubricant is at least two selected from hydrocarbon lubricants, amide lubricants, ester lubricants, organic salt lubricants, fluorine-containing lubricants, C8-30 alcohol lubricants and other types of lubricants.

[0035] According to some preferred aspects of the present invention, the lubricant is composed of an ester lubricant and one or more lubricants selected from amide lubricants, hydrocarbon lubricants, organic salt lubricants, fluorine-containing lubricants, C8-30 alcohol lubricants and other types of lubricants.

[0036] According to some preferred and specific aspects of the present invention, the ester lubricant accounts for 20-60% of the mass percentage of the lubricant.

[0037] According to some preferred aspects of the present invention, the ester lubricant is composed of a combination of montan wax and one or more selected from glycerol monooleate, pentaerythritol stearate, ester lubricant G16 and ester lubricant G60.

[0038] According to some specific and preferred aspects of the present invention, the hydrocarbon lubricant is a low-density polyethylene compound SA13-9 and / or polyethylene wax.

[0039] According to some specific and preferred aspects of the present invention, the amide lubricant is a combination of one or more selected from N,N'-diethylenebisstearamide, oleamide and amide wax.

[0040] According to some specific and preferred aspects of the present invention, the C8-30 alcohol lubricant is stearyl alcohol (also known as n-octadecyl alcohol).

[0041] According to some specific and preferred aspects of the present invention, the organic salt lubricant is a combination of one or more selected from calcium stearate, magnesium stearate and sodium stearate.

[0042] According to some specific and preferred aspects of the present invention, the fluorine-containing lubricant is a nonionic fluorocarbon surfactant.

[0043] According to some specific and preferred aspects of the present invention, the other type of lubricant is molybdenum disulfide and / or oxidized polyethylene wax.

[0044] According to some specific and preferred aspects of the present invention, the nucleating agent is composed of an inorganic nucleating agent and an organic nucleating agent in a feeding mass ratio of 1:0.1-10, preferably in a feeding mass ratio of 1:0.2-5.

[0045] According to some specific aspects of the present invention, the inorganic nucleating agent is a combination of one or more selected from talc, mica and silica.

[0046] According to some specific aspects of the present invention, the organic nucleating agent is a combination of one or more of dibenzylidene sorbitol and its derivatives, organic carboxylic acid sodium salts and its derivatives, and di(2,4-tert-butylphenyl) phosphate sodium salts and its derivatives. In some embodiments of the present invention, the dibenzylidene sorbitol and its derivatives may be Millad 3988, Millad NX8000, etc., the di(2,4-tert-butylphenyl) phosphate sodium salts and its derivatives may be sodium bis(4-tert-butylphenyl) phosphate, NA-11, NA-21, etc., and the organic carboxylic acid sodium salts and its derivatives may be benzoate, cinnamate, sodium tert-butylbenzoate, and sodium dehydroabietic acid, etc.

[0047] According to some specific aspects of the present invention, the antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant, the hindered phenol antioxidant is selected from the group consisting of Irganox 1076, Irganox 1135, Irganox 1520, Irganox565, 2,6-di-tert-butyl-p-cresol, Irganox2246, Irganox259, Irganox245, Irganox1081, Irganox1035, Irganox MD-1024, Irganox 1019, Irganox1010, Irganox1330, Irganox3114 and Cyanox1010, the phosphite antioxidant is selected from the group consisting of Irgafos 168, Ultranox 626, Mark PEP-36, Cyanox2777, Sandstab A combination of one or more of P-EPQ and Phosphote A.

[0048] Due to the adoption of the above technical solution, the present invention has the following advantages compared with the prior art:

[0049] In some embodiments, the present invention uses a composite UV absorber and a specific lubricant to achieve excellent UV resistance without reducing the transparency of the cable tie, and improves the fluidity of the polypropylene composition of the present invention relative to the mold, so that it can quickly fill the mold within a limited space and time, thereby being able to produce thin-walled polypropylene cable ties with a high aspect ratio.

[0050] Furthermore, in other embodiments, the present invention innovatively adopts a composite ultraviolet absorber, supplemented by a specific toughening agent and a lubricant, to improve the fluidity of the polypropylene composition of the present invention relative to the mold, so that the mold can be quickly filled in a limited space and time, thereby being able to produce a thin-walled, high aspect ratio polypropylene cable tie. At the same time, it not only has good appearance transparency and strong ultraviolet resistance, but also avoids the loss of transparency of the cable tie caused by the use of zinc oxide, carbon black or similar milky white fillers in the prior art to improve the ultraviolet resistance. It also has the advantages of high and low temperature impact resistance and strong tripping force (which is a comprehensive reflection of the mechanical properties of the cable tie, such as tensile properties and bending properties), and can be used in harsh environments. DETAILED DESCRIPTION

[0051] The above scheme is further described below in conjunction with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are generally the conditions in routine experiments.

[0052] In the following, unless otherwise specified, all raw materials are commercially available or prepared by conventional methods in the art.

[0053] Examples 1-4

[0054] The thin-walled, high-aspect-ratio polypropylene cable ties provided in these embodiments are UV-resistant and high-low temperature impact-resistant, and are made by injection molding of a polypropylene composition at injection molding temperatures (zones 1-4): 150°C, 220°C, 230°C, and 225°C.

[0055] The raw material formula of the polypropylene composition is shown in Table 1 below.

[0056] In the table below, the isotactic homopolypropylene has a melting peak temperature of 165°C, a melting enthalpy of 84.4 J / g, a crystallization peak temperature of 130°C, a crystallization enthalpy of 90.2 J / g, and a melt index of 62 g / 10 min, and is purchased from China Coal Shaanxi Yulin Energy Chemical Co., Ltd.; the block copolymer polypropylene has a melting peak temperature of 163°C, a melting enthalpy of 79.9 J / g, a crystallization peak temperature of 123°C, a crystallization enthalpy of 91.7 J / g, and a melt index of 58 g / 10 min, and is purchased from Borouge Plastics (Shanghai) Co., Ltd.

[0057] Table 1

[0058]

[0059]

[0060] The polypropylene composition is prepared by weighing the raw materials according to the formula, mixing them, extruding them into granules through a twin-screw extruder, and drying them at 80° C. for 6 hours.

[0061] Among them, the temperature settings of each zone of the twin-screw extruder are: 90℃, 120℃, 180℃, 180℃, 180℃, 180℃, 180℃, 180℃, 180℃, 180℃, 180℃, starting from the main feeding, the die temperature is 175℃, and the screw speed is 450 rpm.

[0062] Comparative Example 1

[0063] The method is basically the same as Example 1, except that the composite ultraviolet absorber is replaced by a single 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole.

[0064] Comparative Example 2

[0065] The method is basically the same as Example 1, with the only difference being that a single toughening agent, butadiene rubber, is used.

[0066] Comparative Example 3

[0067] The method is basically the same as Example 1, with the only difference being that a single toughening agent, styrene-butadiene-styrene block copolymer, is used.

[0068] Comparative Example 4

[0069] The method is basically the same as Example 1, except that a single lubricant, montan wax, is used.

[0070] Comparative Example 5

[0071] The method is basically the same as Example 1, except that a single lubricant, n-octadecyl alcohol, is used.

[0072] Performance Testing

[0073] The polypropylene cable ties obtained in Examples 1-4 and Comparative Examples 1-5 were subjected to the following performance tests. The specific results are shown in Table 2. (The test cable ties are 4.8×250mm series products)

[0074] Among them, the low-temperature drop hammer test (reflecting toughness), -40℃ operating temperature test, and tripping force (reflecting comprehensive mechanical properties) test refer to the standard UL62275.

[0075] The low-temperature flexural test method is to place the sample in an environment with a temperature of 23±2℃ and a relative humidity of 50% for 48 hours, then place it in a low-temperature test chamber set at a specific temperature. After freezing for 4 hours, it is quickly folded in the low-temperature test chamber for a test. If there is no breakage, it passes the test.

[0076] The anti-ultraviolet test refers to GB / T 14522-93. The temperature during ultraviolet irradiation is 60±2℃, the relative humidity is 50%, and the irradiation time is 1000 hours.

[0077] High and Low Temperature Impact Test: The test sample is placed in a high and low temperature test chamber. The test temperature is raised to 120°C over 30 minutes and held for 2 hours. The test temperature is then lowered to -30°C over 30 minutes and held for 2 hours. The test temperature is then raised to 120°C over 30 minutes and held for 2 hours. After 10 cycles, the test temperature is lowered to room temperature. After 24 hours at room temperature, the tripping force is tested. A drop in tripping force of less than 20% is considered acceptable.

[0078] Table 2

[0079]

[0080] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A UV-resistant polypropylene cable tie, characterized in that: The UV-resistant polypropylene cable tie is made by injection molding of a polypropylene composition; The polypropylene composition comprises the following components in percentage by mass: 90-98.5% of polypropylene material, 0.1-2.5% of composite ultraviolet absorber, 1-8% of toughening agent, 0.2-1% of lubricant, 0.01-1% of nucleating agent and 0.01-0.5% of antioxidant; The composite ultraviolet absorber is composed of a benzotriazole ultraviolet absorber and at least one selected from a benzophenone ultraviolet absorber and an amino ultraviolet absorber; The lubricant is composed of montan wax and stearyl alcohol, or composed of montan wax, ester lubricant G16 and stearyl alcohol, or composed of montan wax, ester lubricant G16 and polyethylene wax, or composed of montan wax and N,N'-diethylenebisstearamide; The toughening agent is composed of butadiene rubber and styrene-butadiene-styrene block copolymer, or is composed of butadiene rubber and octene-ethylene copolymer, or is composed of styrene-butadiene-styrene block copolymer and ethylene propylene diene rubber, or is composed of ethylene propylene diene rubber and octene-ethylene copolymer.

2. The UV-resistant polypropylene cable tie according to claim 1, characterized in that: The nucleating agent is composed of an inorganic nucleating agent and an organic nucleating agent in a feed mass ratio of 1:0.1-10.

3. The UV-resistant polypropylene cable tie according to claim 2, characterized in that: The nucleating agent is composed of an inorganic nucleating agent and an organic nucleating agent in a feed mass ratio of 1:0.2-5.

4. The UV-resistant polypropylene cable tie according to claim 1, characterized in that: The antioxidant is a hindered phenol antioxidant and / or a phosphite antioxidant.

5. The UV-resistant polypropylene cable tie according to claim 1, characterized in that: The benzophenone ultraviolet absorber is a combination of one or more selected from (2,4-dihydroxyphenyl)phenyl ketone, 2-hydroxy-4-n-octyloxybenzophenone and (2-hydroxy-4-methoxyphenyl)phenyl ketone; The benzotriazole ultraviolet absorber is a combination of one or more selected from 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'bis(a,a-dimethylbenzyl)phenyl)benzotriazole, bis(3-benzotriazolyl-2-hydroxy-5-tert-octylphenyl)methane, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole; The amino ultraviolet absorber is poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]}.

6. The UV-resistant polypropylene cable tie according to claim 1, characterized in that: The composite ultraviolet absorber is composed of 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole and poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]}, or poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6,-tetramethyl-4-piperidinyl)imino]}. 6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]} and 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, or 2-hydroxy-4-n-octyloxybenzophenone and 2-[2-hydroxy-5-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole, or 2-hydroxy-4-n-octyloxybenzophenone and 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole.

7. The UV-resistant polypropylene cable tie according to any one of claims 1 to 6, characterized in that: The polypropylene material has a melting peak temperature of 155 to 170° C., a melting enthalpy of 60 to 100 J / g, a crystallization peak temperature of 110 to 135° C., and a crystallization enthalpy of 70 to 105 J / g; The melt index of the polypropylene material is 5-100 g / 10 min, and the melt index is measured at a temperature of 230° C. and a load of 2.16 kg.

8. The UV-resistant polypropylene cable tie according to any one of claims 1 to 6, characterized in that: The polypropylene material is a combination of one or more selected from isotactic homopolypropylene, syndiotactic homopolypropylene, random homopolypropylene, block copolymer polypropylene with an ethylene content of 7-15%, and random copolymer polypropylene; the melt index of the polypropylene material is 20-70 g / 10 min, and the melt index is measured at a temperature of 230° C. and a load of 2.16 kg.

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