Regenerated polypropylene cable tie material and preparation method thereof

Abstract

The invention discloses a regenerated polypropylene cable tie material and a preparation method thereof, and the regenerated polypropylene cable tie material is prepared from the following raw materials in parts by weight: 10-40 parts of regenerated polypropylene, 10-60 parts of high-impact co-polypropylene and 10-40 parts of high-crystalline co-polypropylene, totaling 100 parts. 0-20 parts of a toughening agent, 0.4-1 part of an antioxidant, 0.4-1 part of a coupling agent, 0.4-1 part of a lubricant and 0.5-2 parts of black masterbatch. By adding the flexibilizer, the mechanical property of the regenerated polypropylene is improved, the regenerated polypropylene meets the use requirements of the polypropylene cable tie, and meanwhile, the regenerated polypropylene is low in price, so that the cable tie material has an obvious price advantage.

Description

Technical Field

[0001] The invention belongs to the technical field of polypropylene modification, and in particular relates to a recycled polypropylene cable tie material and a preparation method thereof. Background Art

[0002] Polypropylene (PP) has the advantages of wide use, low price, low toxicity, easy processing and molding, good electrical insulation and high chemical stability. It is widely used in manufacturing and processing fields such as packaging, medical devices, automobiles, textiles and building materials.

[0003] With the large-scale application of plastic products, waste polypropylene has become one of the largest waste polymer materials. How to recycle recycled polypropylene into high-value products has become a new research hotspot in many plastic consumption fields. The composition and performance of recycled polypropylene vary greatly depending on its source. The modification of recycled polypropylene requires the selection of appropriate base materials for formula design.

[0004] Cable ties are a type of wire harness product, and their main function is to fasten wire harnesses. They have the characteristics of fast binding, self-locking fastening, good insulation, and easy use. Cable ties can be widely used to fix the internal connecting wires of electronic appliances and automotive wiring harnesses to prevent the wiring harnesses from moving or being interfered with by other components, thereby damaging the wiring harnesses. They can also be used to tie items in handicrafts, gardening, agriculture, etc. The demand for cable ties is increasing at a rate of 12% to 15% year by year.

[0005] Nylon cable ties are the most commonly used cable ties. More than 90% of the cable ties on the market are nylon products, which have the characteristics of strong bearing capacity, fatigue resistance, and high temperature resistance. For example, patent document CN115651397A discloses a nylon cable tie material, a nylon cable tie and a preparation method thereof, which can effectively solve the technical problem that the existing nylon cable ties cannot take into account both low-temperature mechanical properties and heat resistance at the same time. However, compared with polypropylene cable ties, nylon cable ties have the disadvantages of high hygroscopicity and high price. In particular, the high hygroscopicity of nylon leads to the fact that in some high-humidity use environments, the release force of the cable tie will gradually decrease with the increase of environmental humidity.

[0006] Polypropylene cable ties are not hygroscopic, and the relative humidity of the environment has almost no effect on the mechanical properties of the product. Therefore, the development of polypropylene cable ties in some fields will help further expand the application areas of cable ties. However, due to its own structure, polypropylene has defects such as poor low-temperature performance, low notch impact strength, and poor light resistance. Therefore, if recycled polypropylene cable ties are prepared, the production machine and process requirements are very high, and the material rigidity and toughness requirements are also very high.

[0007] Patent document CN116144099A discloses a thin-walled high aspect ratio polypropylene cable tie and its application, which is made of a polypropylene composition, which includes 94-99% polypropylene material, 0.1-2.5% composite antistatic agent, 0.1-1% anti-copper agent, 0.2-1% lubricant, 0.01-1% nucleating agent, 0.01-0.5% antioxidant and 0.01-0.3% melt index regulator; it also includes a composite antistatic agent, an anti-copper agent and a melt index regulator, and the composite antistatic agent is The composition of N,N-di(2-hydroxyethyl) dodecylamide and sodium lauroyl isethionate, the lubricant is montan wax, amide lubricant and carboxylate lubricant, the amide lubricant is N,N'-diethylenebisstearamide, the carboxylate lubricant is calcium stearate; the organic nucleating agent is a combination of one or more of adipate, dibenzylidene sorbitol and its derivatives, di(2,4-tert-butylphenyl) phosphate sodium salt and its derivatives, benzoate, cinnamate, sodium tert-butylbenzoate and sodium dehydroabietic acid. Although it has excellent copper resistance, the melt index regulator used in the document has a certain influence on the impact performance of the material and does not consider the light aging performance of the material.

[0008] Recycled polypropylene refers to recycled polypropylene products (such as battery shells, PP plastic bottles, PP plastic frames, etc.) that are crushed and reheated to make recycled polypropylene materials. Compared with new polypropylene raw materials, some molecular chains of recycled polypropylene are aged and broken, resulting in a decrease in its mechanical properties. When using recycled polypropylene as cable tie material, it is necessary to consider issues such as improving its mechanical properties. Summary of the invention

[0009] The purpose of the present invention is to provide a recycled polypropylene cable tie material and a preparation method thereof. The material has excellent injection molding processing and low price. On the basis of improving the toughness of the material, it also has the excellent properties of high wear resistance, high weather resistance and low temperature resistance. It can be used in polypropylene cable ties with strict requirements on weather resistance and toughness.

[0010] The purpose of the present invention is achieved through the following technical solutions:

[0011] A recycled polypropylene cable tie material of the present invention is characterized in that it is made from the following raw materials in parts by weight, with a total of 100 parts:

[0012] 10-40 parts of recycled polypropylene, 10-60 parts of high-impact copolymer polypropylene, 10-40 parts of high-crystalline copolymer polypropylene, 0-20 parts of toughening agent, 0.4-1 parts of antioxidant, 0.2-1 parts of light stabilizer, 0.1-1 parts of nucleating agent, 0.4-1 parts of lubricant, 0.5-2 parts of black masterbatch; the nucleating agent is a diphenylmethylene sorbitol nucleating agent;

[0013] The recycled polypropylene is recycled polypropylene crushed material or particles, and its melt index is 1-5g / 10min; the high impact copolymer polypropylene is a high impact copolymer polypropylene with a melt index of 1-30g / 10min; the high crystalline copolymer polypropylene is a high modulus copolymer polypropylene with a melt index of 1-60g / 10min;

[0014] The toughening agent is an ethylene-octene copolymer having a melt index of 0.5 to 50 g / 10 min;

[0015] The antioxidant is at least one of a hindered phenol antioxidant, a phosphite antioxidant, and an antioxidant DSTP, preferably at least one of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite), and antioxidant DSTP (distearyl thiodipropionate);

[0016] The light stabilizer is at least one of light stabilizer 3808, UV3853, and UV-2908 (3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl);

[0017] The lubricant is at least one of silicone masterbatch, calcium stearate, polyethylene wax, and erucic acid amide; the black masterbatch is a black masterbatch with polypropylene (PP) or polyethylene (PE) as a carrier.

[0018] The preparation method of a recycled polypropylene cable tie material described in the present invention comprises the following steps: uniformly mixing the raw materials in a high-speed mixer, then adding the raw materials into a twin-screw extruder, melt blending, extruding, cooling, and granulating; the process conditions are: zone one 170-210°C, zone two 180-230°C, zone three 180-230°C, zone four 180-230°C, and the screw speed is 200-600 rpm.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] The present invention uses recycled polypropylene material as the cable tie material. The low price of recycled polypropylene makes the cable tie material have obvious price advantages. At the same time, it reduces the dependence on polypropylene raw materials, reduces the impact of plastic waste on the environment, and helps to reduce pollution and protect the environment.

[0021] In order to ensure the mechanical properties of recycled polypropylene, the present invention adopts dibenzylidene sorbitol compounds as nucleating agents. There are two free hydroxyl groups in the molecules of dibenzylidene sorbitol compounds. When the polypropylene resin is melted, a three-dimensional nanofiber network with a supramolecular structure can be formed through the hydrogen bonding of the free hydroxyl groups. The surface of the network forms a crystal nucleation center, which promotes the formation of heterogeneous nucleation crystallization, thereby improving the molecular chain strength of the recycled polypropylene, and controlling the growth of spherulites to increase the number of crystal nuclei, make the crystallization more perfect, and make the force more uniform, thereby improving the mechanical properties of the recycled polypropylene and meeting the use requirements of the polypropylene cable tie material. DETAILED DESCRIPTION

[0022] Those skilled in the art should realize that the present embodiment is only used to illustrate the present invention, but not to limit the present invention.

[0023] The raw materials used in the present invention are all commercially available products.

[0024] The formula composition of the recycled polypropylene cable tie material of Examples 1 to 5 and Comparative Examples 1 to 3 is shown in Table 1, and is prepared by the following method: the raw materials are mixed evenly in a high mixer, the mixed raw materials are added to a twin-screw extruder, and melt blended, extruded, cooled, and granulated; the temperature from the feed port to the die is 180°C, 190°C, 210°C, 200°C, 210°C, 210°C, 200°C, 210°C, 210°C, 210°C, 220°C, 230°C, and the main engine speed is 450 rpm.

[0025] The raw materials used in Examples 1 to 5 and Comparative Examples 1 to 3 are:

[0026] Recycled polypropylene: black battery shell recycled material produced by Jieshou Dongwei Plastics Co., Ltd.

[0027] High impact copolymer polypropylene: K3029 grade produced by Taiwan Chemical Company;

[0028] Highly crystalline copolymer polypropylene: BX3500 grade produced by SK Chemical Company;

[0029] Toughener: Ethylene octene copolymer, POE 8842 produced by Dow Chemical Company;

[0030] Antioxidant: The mass ratio of antioxidant 1010 and antioxidant 168 is 1:1; Light stabilizer: UV-3808 produced by American Cytec Corporation;

[0031] Lubricant: silicone masterbatch, MB50-001 brand produced by Dow Corning;

[0032] Nucleating agent: diphenylmethylene sorbitol nucleating agent, Millad 3940 produced by Milliken & Company;

[0033] Black masterbatch: UN5030 black masterbatch produced by Beijing Hua Hi-Tech Co., Ltd.

[0034] Table 1 Raw material formula of Examples 1 to 5 and Comparative Examples 1 to 3, parts by weight

[0035]

[0036]

[0037] Comparative Example 3 uses talcum powder as an inorganic nucleating agent, and the remaining raw material formula and preparation method of Comparative Example 3 are the same as those of Example 5.

[0038] The tensile strength, modulus, notched impact and aging tests were performed on the modified polypropylene material injection molding specimens prepared in Examples 1 to 5 and Comparative Examples 1 to 3. The performance test results of the modified polypropylene material prepared in Examples 1 to 5 and Comparative Examples 1 to 3 are listed in Table 2.

[0039] Table 2 Performance test results of Examples 1 to 5 and Comparative Examples 1 to 3

[0040]

[0041] From the data in Table 2, it can be seen that the modified polypropylene materials of Examples 1 to 5 gradually increase in density and gradually decrease in flexural modulus as the amount of recycled polypropylene increases. When the amount of recycled polypropylene added is ≤40%, the tensile strength is above 18MPa, the flexural modulus is above 1200MPa, and the notched impact strength at room temperature is above 15kJ / m 2 Above, low temperature notched impact strength is 3kJ / m 2 The above, and the low-temperature notch impact will increase with the increase of POE, and the thermal oxygen aging and xenon lamp aging also meet the material use standards. This is because the toughening agent POE forms a uniform structure with polypropylene in the material, which has a good toughening effect. It can absorb internal stress when receiving low-temperature impact and improve the low-temperature tolerance of polypropylene materials. The amount of recycled polypropylene in Comparative Example 2 is 50%. Although the increase of POE can meet the notch impact requirements of the material, its tensile strength and flexural modulus are seriously reduced, which cannot meet customer standards.

[0042] In Example 5, a dibenzylidene sorbitol compound nucleating agent is added, while in Comparative Example 1, no nucleating agent is added, and in Comparative Example 3, an inorganic nucleating agent, talcum powder, is added. The difference between Example 5 and Comparative Example 3 and Comparative Example 1 is only that there is or is not a nucleating agent and the type of the nucleating agent is different. Compared with Comparative Example 1, the mechanical properties of Example 5 are all improved to a certain extent, and the added dibenzylidene sorbitol compound can effectively improve the various mechanical properties of the recycled polypropylene. Compared with Comparative Example 3, the bending performance of Example 5 is improved to a certain extent, and the standard of the product can be met. This is because there are two free hydroxyl groups in the dibenzylidene sorbitol compound molecule, and when the polypropylene resin is melted, a three-dimensional nanofiber network with a supramolecular structure can be formed through the hydrogen bonding of the free hydroxyl groups, and the center of crystallization nucleation is formed on its surface, which promotes the formation of heterogeneous nucleation crystallization, thereby improving the molecular chain strength of the recycled polypropylene, and then improving its mechanical properties.

Claims

1. A recycled polypropylene cable tie material, characterized in that: It is prepared from the following raw materials in parts by weight, with a total of 100 parts: 10-40 parts of recycled polypropylene, 10-60 parts of high-impact copolymer polypropylene, 10-40 parts of high-crystalline copolymer polypropylene, 0-20 parts of toughening agent, 0.4-1 parts of antioxidant, 0.2-1 parts of light stabilizer, 0.1-1 parts of nucleating agent, 0.4-1 parts of lubricant, and 0.5-2 parts of black masterbatch; the nucleating agent is a diphenylmethylene sorbitol nucleating agent.

2. The recycled polypropylene cable tie material according to claim 1, characterized in that: The recycled polypropylene is recycled polypropylene crushed material or particles, and its melt index is 1-5g / 10min; the high impact copolymer polypropylene is a high impact copolymer polypropylene with a melt index of 1-30g / 10min; the high crystalline copolymer polypropylene is a high modulus copolymer polypropylene with a melt index of 1-60g / 10min.

3. The recycled polypropylene cable tie material according to claim 1, characterized in that: The toughening agent is an ethylene-octene copolymer with a melt index of 0.5 to 50 g / 10 min.

4. The recycled polypropylene cable tie material according to claim 1, characterized in that: The antioxidant is at least one of a hindered phenol antioxidant, a phosphite antioxidant, and an antioxidant DSTP.

5. The recycled polypropylene cable tie material according to claim 1, characterized in that: The light stabilizer is at least one of light stabilizer 3808, UV3853, and UV-2908.

6. The recycled polypropylene cable tie material according to claim 1, characterized in that: The lubricant is at least one of silicone masterbatch, calcium stearate, polyethylene wax and erucic acid amide; the black masterbatch is a black masterbatch with polypropylene or polyethylene as a carrier.

7. A method for preparing a recycled polypropylene cable tie material according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: uniformly mixing the raw materials in a high-speed mixer, then adding the raw materials into a twin-screw extruder, melt blending, extruding, cooling, and granulating; the process conditions are: zone one 170-210°C, zone two 180-230°C, zone three 180-230°C, zone four 180-230°C, and a screw speed of 200-600 rpm.

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