Halogen-free polyolefin composite material, and preparation method and application thereof

Abstract

The present application relates to a kind of halogen-free polyolefin composite and its preparation method and application.The halogen-free polyolefin composite includes the following weight parts of components: polyolefin resin 30~50 parts, flame retardant 50~100 parts, crosslinking aid 1~2 parts, UV aid 0.1~0.2 parts, potassium titanate whisker 2~5 parts, potassium titanate magnesium 2~5 parts;Wherein, the flame retardant is inorganic hydroxide;The UV aid is hindered phenol light stabilizer.The polyolefin composite is added potassium titanate whisker and the potassium titanate magnesium with lamellar structure, the synergistic effect of the two components can greatly improve the barrier effect of polyolefin resin to ultraviolet light wave, realize only a small amount of UV aid is needed, i.e.polyolefin resin can have good ultraviolet light aging resistance.

Description

Technical Field

[0001] This invention relates to the field of general plastics technology, and more specifically, to a halogen-free polyolefin composite material, its preparation method, and its application. Background Technology

[0002] Polyvinyl chloride (PVC) is widely used as a sheathing and insulation material for wires and cables due to its excellent electrical insulation, corrosion resistance, flame retardancy, and processing properties. However, because it contains halogens, it releases a large amount of smoke and toxic gases when burned, which is not conducive to environmentally friendly long-term development. Therefore, in recent years, halogen-free polyolefin materials have become a hot topic in the wire and cable industry.

[0003] The flame retardancy of polyolefin materials is not ideal, and flame retardants need to be added to improve their flame retardancy. To ensure that existing halogen-free polyolefin materials have excellent flame retardancy, a large amount of inorganic hydroxide is generally added. However, adding too much inorganic hydroxide will cause uneven distribution in the polyolefin matrix, resulting in partial agglomeration or delamination. This weakens the bonding ability between the matrix and the inorganic hydroxide, thereby reducing the mechanical properties of the polyolefin material. Especially under sunlight, its mechanical properties degrade significantly. Therefore, it is particularly important to develop UV-resistant modification schemes for halogen-free polyolefin materials.

[0004] Currently, the UV aging resistance of polyolefin materials is generally improved by adding UV-resistant additives. To achieve good UV aging resistance, the proportion of UV-resistant additives usually needs to be ≥0.5%. Summary of the Invention

[0005] The primary objective of this invention is to overcome the shortcomings and deficiencies of existing halogen-free polyolefin materials, which suffer from significant mechanical property degradation due to photoaging and cannot meet application requirements. This invention provides a halogen-free polyolefin composite material that, through the synergistic effect of adding potassium titanate whiskers, potassium magnesium titanate, and UV-resistant additives, enables the polyolefin composite material to have excellent resistance to ultraviolet aging.

[0006] A further object of the present invention is to provide a method for preparing the above-mentioned halogen-free polyolefin composite material.

[0007] A further object of the present invention is to provide the application of the above-mentioned halogen-free polyolefin composite material in the preparation of sheathing or insulating materials for wires and cables.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0009] A halogen-free polyolefin composite material comprising the following components in parts by weight:

[0010] 30-50 parts of polyolefin resin;

[0011]

[0012] The flame retardant is an inorganic hydroxide; the UV-resistant additive is a hindered phenolic light stabilizer.

[0013] Potassium titanate has a certain ability to reflect light radiation. Potassium titanate whiskers have a rod-like structure, and their efficiency in blocking light waves when dispersed in polyolefin resin is relatively low, with limited ability to reduce light radiation. Potassium magnesium titanate is a sheet material with good light blocking effect. When combined with potassium titanate whiskers and dispersed in polyolefin resin, the blocking effect can be greatly improved. This allows for the effective reduction of aging reactions that generate free radicals with only a small amount of anti-UV additives, giving the polyolefin composite material good mechanical properties against UV aging.

[0014] The potassium titanate whiskers in this invention have the general chemical formula K2O·n(TiO2), where n = 6 or 8;

[0015] The potassium magnesium titanate has the chemical formula K. 0.8 Mg 0.4 Ti 1.6 O4.

[0016] Preferably, those skilled in the art can select parameters within the weight range of flame retardant, potassium titanate whiskers, or potassium magnesium titanate according to actual needs. For example, the weight of the flame retardant can also be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, or any value within the above range.

[0017] The potassium titanate whiskers can be in the form of 2, 3, 4 or 5 parts by weight.

[0018] The potassium magnesium titanate may be in the form of 2, 3, 4 or 5 parts by weight.

[0019] Preferably, the polyolefin resin is at least one of polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer (EMA), ethylene-butyl acrylate copolymer (EBA), ethylene-ethyl acrylate copolymer (EEA), or polyethylene octene copolymer (POE).

[0020] More preferably, the polyolefin resin is a blend of polyethylene, ethylene-vinyl acetate copolymer and polyethylene octene elastomer.

[0021] More preferably, the weight ratio of polyethylene, ethylene-vinyl acetate copolymer and polyethylene octene copolymer is 1-2:2-4:1-2.

[0022] Specifically, the weight ratio of polyethylene, ethylene-vinyl acetate copolymer and polyethylene octene copolymer is 1:2:1.

[0023] Preferably, the melt flow index of the polyolefin resin measured at 190°C and 2.16 kg load is 0.5 to 10 g / 10 min.

[0024] More preferably, the melt index of the polyolefin resin measured at 190°C and 2.16 kg load is 1 to 6 g / 10 min.

[0025] The melt index of the polyolefin resin in this invention can be measured according to the GB / T 3682-2018 standard.

[0026] Preferably, the flame retardant is at least one of aluminum hydroxide and magnesium hydroxide.

[0027] Preferably, the potassium titanate whiskers have a diameter distribution of 0.1–0.6 μm and a length distribution of 3–20 μm.

[0028] The diameter and length distribution of the potassium titanate whiskers were observed using a scanning electron microscope at a magnification of 1000-3000 times, and were obtained by averaging the results from the conditions of the potassium titanate whiskers in three randomly selected specific observation areas.

[0029] Preferably, the potassium titanate whiskers can also be surface modified with a coupling agent to obtain modified potassium titanate whiskers. Modifying the potassium titanate whiskers with a coupling agent can improve the compatibility between the potassium titanate whiskers and the polyolefin resin, thereby making the potassium titanate whiskers uniformly dispersed in the polyolefin resin, which is beneficial to further improve the UV aging resistance of the polyolefin resin.

[0030] Generally, the potassium magnesium titanate has a flake-like morphology with an average thickness of 0.5–2 μm and a diameter distribution of 2–10 μm.

[0031] The morphology, average thickness, and diameter distribution of the potassium magnesium titanate were observed using a scanning electron microscope at a magnification of 1000-3000x, and were obtained by averaging the results from the potassium magnesium titanate in three randomly selected specific observation areas.

[0032] More preferably, the coupling agent is at least one of a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

[0033] More preferably, the weight ratio of the potassium titanate whiskers to the coupling agent is 100:2.5 to 10.

[0034] More preferably, the weight ratio of the potassium titanate whiskers to the coupling agent is 100:5 to 10.

[0035] The modified potassium titanate whiskers of this invention can be prepared by the following method:

[0036] After drying potassium titanate whiskers at 60–80°C for 12 hours, add them to a mixer. Weigh out the coupling agent according to the mass ratio and add it to the potassium titanate whiskers. Stir for 10–30 minutes to obtain modified potassium titanate whiskers.

[0037] Preferably, the crosslinking aid is at least one of triallyl isocyanurate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate.

[0038] More preferably, the crosslinking aid is triallyl isocyanurate.

[0039] Preferably, the halogen-free polyolefin composite material further includes 2 to 5 parts of antioxidant.

[0040] More preferably, the antioxidant includes a primary antioxidant and a secondary antioxidant. The primary antioxidant may be antioxidant 1790, and the secondary antioxidant may be at least one of antioxidant 168 and antioxidant DLTDP.

[0041] Specifically, the antioxidant is a compound of antioxidant 1790, antioxidant 168 and antioxidant DLTDP, and the mass ratio of antioxidant 1790, antioxidant 168 and antioxidant DLTDP is 3:1:2.

[0042] The preparation method of the above-mentioned halogen-free polyolefin composite material includes the following steps: mixing the components, melt extruding, and granulating to obtain the halogen-free polyolefin composite material.

[0043] The above-mentioned halogen-free polyolefin composite materials are used in the preparation of sheathing or insulation materials for wires and cables.

[0044] Preferably, the sheath of the wire and cable is the sheath of a photovoltaic wire and cable.

[0045] Compared with the prior art, the beneficial effects of the present invention are:

[0046] This invention incorporates potassium titanate whiskers and layered potassium magnesium titanate into polyolefin resin. The synergistic effect of these two components can greatly enhance the blocking effect of polyolefin resin on ultraviolet light waves, enabling polyolefin resin to have good mechanical properties resistant to ultraviolet aging with only a small amount of anti-UV additives. Detailed Implementation

[0047] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0048] The reagents used in the various embodiments and comparative examples of this invention are described below:

[0049] Polyolefin resin:

[0050] Polyethylene (PE): LLDPE 3812PA, Exxon;

[0051] Ethylene-vinyl acetate copolymer (EVA): EVA7470M, 26% VA content, Formosa Plastics, Taiwan;

[0052] Polyvinyl octene co-elastomer (POE): POE 58750, Dow Chemical;

[0053] Flame retardant: Aluminum hydroxide, AH-01DG, Luoyang Zhongchao;

[0054] Crosslinking agent: triallyl isocyanurate, commercially available;

[0055] Antioxidants: Antioxidant 1790, antioxidant 168, and antioxidant DLTDP are compounded in a mass ratio of 3:1:2. Antioxidants 1790, antioxidant 168, and antioxidant DLTDP are all commercially available.

[0056] Silane coupling agent: KH-550, Anhui Sibao;

[0057] Titanate coupling agent: FD-201, Zhejiang Boiling Point Chemical Co., Ltd.

[0058] Aluminate coupling agent: HW-133, Zhejiang Boiling Point Chemical Co., Ltd.

[0059] Potassium titanate whiskers:

[0060] PTW-1: K2O·6(TiO2), diameter distribution 0.3-0.6 μm, length distribution 10-20 μm, Otsuka Chemicals;

[0061] PTW-2: K2O·8(TiO2), diameter distribution 0.3-0.6 μm, length distribution 10-20 μm, Otsuka Chemicals;

[0062] PTW-3: K2O·8(TiO2), diameter distribution 0.1-0.3μm, length distribution 3-5μm, Nantong Aoxin;

[0063] PTW-4: K2O·8(TiO2), diameter distribution 0.2-0.5μm, length distribution 5-15μm, Nantong Aoxin;

[0064] The diameter and length distribution of the potassium titanate whiskers were observed using a scanning electron microscope at a magnification of 2000x, and were obtained by averaging the results from the conditions of the potassium titanate whiskers in three randomly selected specific observation areas.

[0065] Modified potassium titanate whiskers:

[0066] Silane-modified PTW-1-1: After drying potassium titanate whiskers at 60-80℃ for 12 hours, add them to a mixer. Weigh out the coupling agent according to the mass ratio of PTW-1:KH-550 of 100:2.5 and add it to the potassium titanate whiskers. Stir for 15 minutes to obtain modified potassium titanate whiskers.

[0067] The preparation steps of other modified potassium titanate whiskers used in the embodiments and comparative examples of this invention are the same as those of silane-modified PTW-1-1. The weight ratios of potassium titanate whiskers and coupling agents are shown in Table 1.

[0068]

[0069] Potassium magnesium titanate: PMTitan-F1, with an average sheet thickness of approximately 1 μm and a diameter distribution of 2-8 μm, manufactured by Tangshan Yuanli New Material Technology Co., Ltd.

[0070] The morphology, average thickness, and diameter distribution of the potassium magnesium titanate were observed using a scanning electron microscope at 2000x magnification, and were obtained by averaging the results from three randomly selected observation areas. Mica powder: C-50, Huajing Mica Co., Ltd.

[0071] Talc powder: TYT-500A, Beihai Group;

[0072] Kaolin: CMP-1, China Kaolin Co., Ltd.;

[0073] Unless otherwise specified, all components (e.g., antioxidants, UV stabilizers) used in the parallel examples and comparative examples are the same commercially available products.

[0074] The performance of the halogen-free polyolefin composite materials provided in the embodiments and comparative examples of the present invention was determined according to the following test methods:

[0075] Xenon lamp aging test: After extruding and granulating the halogen-free polyolefin composite materials of each example and comparative example, they were mixed in a two-roll mill and pressed into sheets with a thickness of 1 mm, which were then cut into dumbbell-shaped strips. Xenon lamp aging tests were conducted according to UL 1581-2023, ASTM G155-21 and UL2556:2021, with an exposure time of 720 h. The strength retention rate and elongation at break retention rate before and after aging were tested.

[0076] The halogen-free polyolefin composite materials of the embodiments and comparative examples of the present invention were prepared by the following preparation method:

[0077] According to the formula, the components are mixed in a high-speed mixer for 10 minutes to obtain a mixture. This mixture is then added to a twin-screw extruder and extruded and granulated to obtain the polyolefin composite material. The temperatures of each zone of the twin-screw extrusion are set sequentially to 100℃, 120℃, 140℃, 150℃, 150℃, 150℃, 150℃, 150℃, 150℃, and 160℃, with a screw speed of 300–400 r / min.

[0078] Examples 1-16

[0079] Examples 1-16 provide a series of halogen-free polyolefin composite materials, the formulations of which are shown in Table 2.

[0080] Table 2. Formulations (parts by weight) for Examples 1-16

[0081]

[0082]

[0083] Comparative Examples 1-7

[0084] Comparative Examples 1–7 provide a series of polyolefin composite materials, the formulations of which are shown in Table 3.

[0085] Table 3 shows the formulations (parts by weight) for Comparative Examples 1–7.

[0086]

[0087] The properties of the polyolefin composites of each embodiment and comparative example were determined according to the test methods mentioned above, and the test results are shown in Table 4.

[0088] Table 4. Performance test results of polyolefin composite materials in each example and comparative example.

[0089]

[0090] As can be seen from Table 4:

[0091] The tensile strength retention rate of the halogen-free polyolefin composite materials in Examples 1 to 16 is all above 90%, and the elongation at break retention rate is all above 80%, indicating that the halogen-free polyolefin composite materials of the present invention can achieve good UV aging resistance with low amounts of UV-resistant additives and magnesium potassium titanate.

[0092] The performance test data from Examples 8 to 10 show that when the mass ratio of potassium titanate whiskers to coupling agent is 100:5 to 10, the polyolefin composite material exhibits good UV aging resistance, with an elongation at break retention rate of over 90%. Examples 9 to 12 show a tensile strength retention rate of over 100% after UV aging, indicating an increase in tensile strength after UV aging. This is because UV irradiation can cause cross-linking within the polyolefin composite material within a certain irradiation time, thereby increasing the tensile strength of the polyolefin composite material.

[0093] As can be seen from Example 13, conventional antioxidants do not significantly improve the system's resistance to UV aging.

[0094] The difference between Comparative Example 1 and Example 2 is that potassium magnesium titanate and potassium titanate whiskers are not added, and the weight ratio of the added UV-resistant additive is 5 times that of Example 2. The retention rates of tensile strength and elongation at break are not much different from those of Example 2, indicating that the polyolefin composite material of the present invention can achieve good UV aging resistance by adding potassium titanate whiskers and potassium magnesium titanate in synergy, while reducing the amount of UV-resistant additive added.

[0095] The difference between Comparative Example 2 and Example 2 is that no UV-resistant additives were added. The resulting polyolefin composite material had a lower retention rate of tensile strength and elongation at break after UV aging.

[0096] The difference between Comparative Example 3 and Example 2 is that potassium magnesium titanate was not added, and the resulting polyolefin composite material had a lower elongation at break retention rate after UV aging.

[0097] The difference between Comparative Example 4 and Example 2 is that potassium titanate whiskers were not added, and the resulting polyolefin composite material had a lower elongation at break retention rate after UV aging.

[0098] The difference between Comparative Example 5 and Example 1 is that potassium magnesium titanate was replaced with mica powder with a lamellar structure. The UV aging resistance of the resulting polyolefin composite material was not as good as that of Example 1. The inventors speculate that this is because the main component of mica is SiO2 (usually 40-50%), and it also contains Al2O3, Fe2O3, K2O, Na2O, MgO and other components. Its lamellar structure is not regular enough and its UV reflectivity is poor. In contrast, the potassium magnesium titanate used in this invention is TiO2 particles. Under certain conditions, K and Mg elements are incorporated into it through the crystal growth process to form potassium magnesium titanate lamellar material. The TiO2 content in potassium magnesium titanate is more than 80%, and its crystal structure is more regular than that of mica. Moreover, TiO2 has a better UV blocking effect than SiO2. Therefore, using potassium magnesium titanate in combination with potassium titanate whiskers can achieve better UV aging resistance than using mica.

[0099] The difference between Comparative Examples 6 and 7 and Example 1 is that potassium magnesium titanate was replaced with talc powder and kaolin with a flake structure. The UV aging resistance of the polyolefin composite materials prepared in Comparative Examples 6 and 7 was not as good as that in Example 1.

[0100] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A halogen-free polyolefin composite material, characterized in that, The components include the following parts by weight: 30-50 parts of polyolefin resin; 50-100 parts of flame retardant; 1-2 parts of crosslinking aid; 0.1 to 0.2 parts of UV-resistant additive; 2-5 parts of potassium titanate whiskers; Potassium magnesium titanate 2-5 parts; The flame retardant is an inorganic hydroxide; the UV-resistant additive is a hindered phenolic light stabilizer.

2. The halogen-free polyolefin composite material according to claim 1, characterized in that, The polyolefin resin is at least one of polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-ethyl acrylate copolymer, or polyethylene octene copolymer.

3. The halogen-free polyolefin composite material according to claim 1, characterized in that, The melt flow index of the polyolefin resin measured at 190°C and under a load of 2.16 kg was 0.5–10 g / 10 min.

4. The halogen-free polyolefin composite material according to claim 1, characterized in that, The flame retardant is at least one of aluminum hydroxide and magnesium hydroxide.

5. The halogen-free polyolefin composite material according to claim 1, characterized in that, The potassium titanate whiskers have a diameter of 0.1–0.6 μm and a length of 3–20 μm.

6. The halogen-free polyolefin composite material according to claim 1, characterized in that, The potassium titanate whiskers can also be surface modified using a coupling agent to obtain modified potassium titanate whiskers.

7. The halogen-free polyolefin composite material according to claim 6, characterized in that, The weight ratio of potassium titanate whiskers to coupling agent is 100:2.5-10.

8. The halogen-free polyolefin composite material according to claim 1, characterized in that, The halogen-free polyolefin composite material also includes 2 to 5 parts of antioxidant.

9. A method for preparing the halogen-free polyolefin composite material according to any one of claims 1 to 8, characterized in that, The process includes the following steps: mixing the components, melt extruding, and granulating to obtain the halogen-free polyolefin composite material.

10. The use of the halogen-free polyolefin composite material according to any one of claims 1 to 8 in the preparation of sheathing or insulating materials for wires and cables.

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