Polypropylene resin for manufacturing weather-proof solar back panel and preparation method of polypropylene resin

Abstract

The invention discloses polypropylene resin for manufacturing a weather-proof solar backboard and a preparation method of the polypropylene resin. The preparation method comprises the following steps: preparing a propylene and ethylene random copolymer, mixing the propylene and ethylene random copolymer with additives such as an antioxidant, an acid removal agent, a nucleating agent and an anti-ultraviolet agent, and then extruding and granulating to prepare the polypropylene resin for manufacturing the weather-proof solar back panel. The resin has good weather resistance and ultraviolet resistance, and can be well applied to manufacturing of weather-resistant solar backboards.

Description

Technical Field

[0001] The invention relates to the field of material preparation, and in particular to a polypropylene resin for manufacturing a weather-resistant solar back panel and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is a common plastic material with good heat resistance, chemical resistance and physical properties. However, polypropylene may experience photoaging when exposed to UV radiation for a long time. Photoaging refers to the chemical and physical changes caused by long-term exposure of materials to UV radiation. In polypropylene, UV radiation can cause oxidation reactions on the surface of the material, causing it to deteriorate, become brittle, crack and other problems. The rate of photoaging depends on the intensity and duration of UV exposure. In order to slow down the photoaging rate of polypropylene, the following measures can be taken: 1. Adding light stabilizers: Light stabilizers are special additives that can absorb and convert UV energy, thereby reducing damage to polypropylene. Commonly used light stabilizers include HALS, UV absorbers, etc. 2. Protective agents: By adding protective agents, the entry of UV rays can be blocked and their impact on polypropylene can be reduced. A common protective agent is pigment, which can provide a physical barrier to block UV rays. 3. Adding antioxidants: Antioxidants can prevent polypropylene from producing free radicals and slow down the occurrence of oxidation reactions, thereby delaying the photoaging process. In addition to taking the above measures, polypropylene can also be prevented from being exposed to UV radiation for a long time through reasonable design and use. However, in the prior art, there are often certain conflicts between the various auxiliary agents, thereby reducing the synergistic effect of the various auxiliary agents. Summary of the invention

[0003] The purpose of the present invention is to provide a high-flow polypropylene resin for the manufacture of weather-resistant solar back panels prepared by random copolymerization of propylene and ethylene, and a preparation method thereof. The resin prepared by the method of the present invention has good processing performance, optical properties, mechanical properties and ultraviolet resistance, and can meet the production and use requirements of weather-resistant solar back panels.

[0004] The present invention first provides a method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet, comprising the following steps:

[0005] S1: preparing a random copolymer of propylene and ethylene;

[0006] S2: mixing the random copolymer of propylene and ethylene prepared in step S1 with an additive;

[0007] S3: Producing polypropylene resin for weather-resistant solar backsheet manufacturing through extrusion granulation;

[0008] in:

[0009] In step S1, the random copolymer of propylene and ethylene has an ethylene content of 0.1 to 5.0 wt%, a melt flow rate of 1 to 50 g / 10 min at 230° C. and 2.16 kg / 10 min, an isotactic index of 95 to 99%, a number average molecular weight of 70,000 to 100,000, and a molecular weight distribution index of 4 to 6;

[0010] In step S2, the mass percentage of the random copolymer of propylene and ethylene is 97.0-99.6%, and the mass percentage of the additive is 0.4-3.0%;

[0011] In step S2, the additives include antioxidants, acid scavengers, nucleating agents and anti-ultraviolet agents.

[0012] Preferably, in step S1, the random copolymer of propylene and ethylene is prepared by the following method: propylene, ethylene and hydrogen are used as raw materials, added into a loop reactor, and a catalyst, a co-catalyst, an electron donor and an antistatic agent are added and stirred evenly, the reaction temperature in the loop reactor is controlled to be 65-72° C., the reaction pressure is 3.3-4.0 MPa, and the hydrogen concentration is 1000-5500 ppm, and the random copolymer of propylene and ethylene is obtained after flash evaporation, steam distillation and drying; wherein the catalyst is DQ-III, the co-catalyst is triethylaluminum (TEAL), the electron donor is DONOR, and the antistatic agent is Atmer 163.

[0013] Preferably, in step S2, the mass percentages of the random copolymer of propylene and ethylene and various additives are:

[0014] Propylene and ethylene random copolymer: 97.0~99.6%;

[0015] Antioxidant: 0.1-1.0%;

[0016] Acid scavenger: 0.1-0.2%;

[0017] Nucleating agent: 0.1-0.8%;

[0018] Anti-ultraviolet agent: 0.1~1.0%.

[0019] Preferably, in step S2, the antioxidant comprises antioxidant A and antioxidant B, wherein:

[0020] Antioxidant A is 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane;

[0021] Antioxidant B is tris(2,4-di-tert-butylphenyl)phosphite;

[0022] The mass percentage of each substance is:

[0023] Antioxidant A: Antioxidant B = 1: (0.2-10);

[0024] (Random copolymer of propylene and ethylene + all additives): (Antioxidant A + Antioxidant B) = 100: (0.1~1).

[0025] Preferably, in step S2, the acid scavenger includes acid scavenger A and acid scavenger B, wherein:

[0026] Acid scavenger A is calcium stearate;

[0027] Acid scavenger B is hydrogenated talc;

[0028] The mass percentage of each substance is:

[0029] Acid scavenger A: Acid scavenger B = 1: (0.5-1.5);

[0030] (random copolymer of propylene and ethylene + all additives): (acid scavenger A + acid scavenger B) =

[0031] 100:(0.1~0.2).

[0032] Preferably, in step S2, the nucleating agent comprises nucleating agent A, nucleating agent B and nucleating agent C, wherein:

[0033] Nucleating agent A: methylene bis(2,4-di-tert-butylphenyl)aluminum phosphate;

[0034] Nucleating agent B: di-(3,4-dimethylbenzylidene) sorbitol;

[0035] Nucleating agent C: di(p-methylbenzylidene)xylitol;

[0036] The mass percentage of each substance is:

[0037] Nucleating agent A: nucleating agent B: nucleating agent C = (0.1-1): (0.1-1): (0.1-1);

[0038] (Random copolymer of propylene and ethylene + all additives): (nucleating agent A + nucleating agent B + nucleating agent C) = 100: (0.1 ~ 0.8).

[0039] Preferably, in step S2, the anti-ultraviolet agent is 2-hydroxy-4-n-octyloxybenzophenone;

[0040] The mass percentage of each substance is:

[0041] (Random copolymer of propylene and ethylene + all additives): anti-ultraviolet agent = 100: (0.1 ~ 1.0).

[0042] Preferably, in step S2, the mixing process is: the propylene and ethylene random copolymer, antioxidant, acid scavenger, nucleating agent and anti-ultraviolet agent are first mixed at a low speed for 0.5 to 1 minute in a high-speed mixer at normal temperature and pressure, then mixed at a high speed for 0.5 to 3 minutes, and finally mixed at a low speed for 0.5 to 1 minute before discharging.

[0043] Preferably, in step S3, the extrusion granulation process is as follows: the mixed mixture of the random copolymer of propylene and ethylene and all additives is heated, sheared and mixed through a twin-screw extruder, the screw aspect ratio is ≥30, the melt temperature is controlled at ≥170°C, and then the mixture melt is extruded from the die hole of the die head and then pulled into strips, cooled in a water tank, and then blown dry or self-dehydrated, and cut into particles by a pelletizer.

[0044] The present invention also provides a polypropylene resin for the manufacture of weather-resistant solar back panels prepared according to the above-mentioned preparation method. The resin has good aging resistance and UV resistance. After long-term UV irradiation (≥1500 hours), it can still maintain more than 60% of the mechanical properties, which can meet the production and use requirements of weather-resistant solar back panels.

[0045] In summary, compared with the prior art, the technical effects of the present invention are:

[0046] The polypropylene of the present invention has a reasonable molecular weight distribution, and two antioxidants are used to cooperate with the light stabilizer through compounding, and the components and proportions of the nucleating agent and the acid scavenger are optimized to ensure that there is no conflict between the additives, thereby greatly improving the aging resistance and anti-ultraviolet performance of the polypropylene. The product obtained by the present invention has good aging resistance and anti-ultraviolet performance, and can still maintain more than 60% of the mechanical properties after 1500 hours of UV light irradiation, which can meet the production and use requirements of weather-resistant solar back panels. DETAILED DESCRIPTION

[0047] The exemplary embodiments of the present invention are described in detail below. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The principles and features of the present invention are described below in conjunction with specific embodiments, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0048] Examples 1 to 6

[0049] S1: Preparation of random copolymer of propylene and ethylene; polymerization grade propylene, ethylene and hydrogen are used as raw materials, added into a loop reactor, and catalyst DQ-Ⅲ, co-catalyst triethylaluminum (TEAL), electron donor DONOR and antistatic agent Atmer163 are added and stirred evenly. Wherein: catalyst DQ-Ⅲ is added according to the output of 40kg / ton, TEAL / propylene = 0.21; TEAL / DONOR = 3, antistatic agent Atmer 163 is 2-3kg / h. Control the reaction temperature in the loop reactor to 65-72°C, the reaction pressure to 3.3-4.0MPa, and the hydrogen concentration to 1500-2500ppm, thereby obtaining a random copolymer of propylene and ethylene polypropylene resin. Its properties are shown in Table 1.

[0050] Table 1 Physical properties of polypropylene resin

[0051] project Test Standards Test Results Melt flow rate, g / 10min GB / T 3682 2.0 Isotactic index, % MA15763 97.0

[0052] S2: According to the ratio shown in Table 2, the propylene and ethylene random copolymer polypropylene, antioxidant and acid scavenger prepared in step S1 are added into a 100L high-speed mixer, and mixed at room temperature and pressure. The high-speed mixer is first mixed at a low speed for 0.5 to 1 minute, then mixed at a high speed for 0.5 to 3 minutes, and finally mixed at a low speed for 0.5 to 1 minute before discharging.

[0053] S3: Then a twin-screw extruder is used for granulation to obtain polypropylene resin for the manufacture of weather-resistant solar back panels. The extrusion granulation process is as follows: the mixture of the random copolymer of propylene and ethylene and all additives is heated, sheared and mixed through a twin-screw extruder, the screw aspect ratio is above 30, the melt temperature is controlled at above 170°C, and then the mixture melt is extruded from the die hole of the die head and then pulled into strips, cooled in a water tank, then blown dry or self-dehydrated, and cut into particles by a pelletizer.

[0054] Test: The temperature was controlled at 170-240°C, and the physical properties of the polypropylene resin used for the weather-resistant solar backsheet were tested and analyzed. The results are shown in Table 3.

[0055] Table 2 Example ratio

[0056]

[0057] Table 3 Physical and chemical properties of polypropylene resin used in the manufacture of weather-resistant solar backsheets

[0058]

[0059] Note: UV aging test: Place the tensile specimens, bending specimens and cantilever beam notched impact specimens in a UV box for 1500 hours to test various properties. Light source: UVA 340, light intensity: 0.76W, cycle conditions: 8h illumination (BPT: 60℃), 4h condensation (BPT: 50℃) (GB / T16422.3).

[0060] It can be seen from the data in Table 3 that the retention rate of the bending modulus of Example 1 after the aging test is 40%, and the retention rate of the simply supported beam notched impact strength is 41%; after adding the anti-ultraviolet agent, the retention rate of the bending modulus of Example 2 is 60%, and the retention rate of the simply supported beam notched impact strength is 62%; the retention rate of the bending modulus of Example 3 is 65%, and the retention rate of the simply supported beam notched impact strength is 62%; the retention rate of the bending modulus of Example 4 is 70%, and the retention rate of the simply supported beam notched impact strength is 61%; the retention rate of the bending modulus of Example 5 is 71%, and the retention rate of the simply supported beam notched impact strength is 82%; the retention rate of the bending modulus of Example 6 is 74%, and the retention rate of the simply supported beam notched impact strength is 78%; the aging resistance of Examples 2, 3, 4, 5, and 6 is significantly improved in the later period after the addition of the anti-ultraviolet agent, and the anti-aging performance is also significantly improved with the increase of the amount of the anti-ultraviolet agent added.

[0061] The present invention may be summarized in other specific forms that do not violate the spirit or main features of the present invention. The above embodiments of the present invention can only be regarded as an explanation of the present invention rather than a limitation. Any minor modifications, equivalent changes and modifications made to the above embodiments based on the essential technology of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet, characterized in that: The following steps are involved: S1: preparing a random copolymer of propylene and ethylene; S2: mixing the random copolymer of propylene and ethylene prepared in step S1 with an additive; S3: Producing polypropylene resin for weather-resistant solar backsheet manufacturing through extrusion granulation; in: In step S1, the random copolymer of propylene and ethylene has an ethylene content of 0.1 to 5.0 wt%, a melt flow rate of 1 to 50 g / 10 min at 230° C. and 2.16 kg / 10 min, an isotactic index of 95 to 99%, a number average molecular weight of 70,000 to 100,000, and a molecular weight distribution index of 4 to 6; In step S2, the mass percentage of the random copolymer of propylene and ethylene is 97.0-99.6%, and the mass percentage of the additive is 0.4-3.0%; In step S2, the additives include antioxidants, acid scavengers, nucleating agents and anti-ultraviolet agents.

2. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S1, the random copolymer of propylene and ethylene is prepared by the following method: propylene, ethylene and hydrogen are used as raw materials, added into a loop reactor, and a catalyst, a co-catalyst, an electron donor and an antistatic agent are added and stirred evenly, the reaction temperature in the loop reactor is controlled to be 65-72° C., the reaction pressure is 3.3-4.0 MPa, and the hydrogen concentration is 1000-5500 ppm, and the random copolymer of propylene and ethylene is obtained after flash evaporation, steam distillation and drying; wherein the catalyst is DQ-III, the co-catalyst is triethylaluminum (TEAL), the electron donor is DONOR, and the antistatic agent is Atmer 163.

3. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S2, the mass percentages of the random copolymer of propylene and ethylene and various additives are: Propylene and ethylene random copolymer: 97.0~99.6%; Antioxidant: 0.1-1.0%; Acid scavenger: 0.1-0.2%; Nucleating agent: 0.1-0.8%; Anti-ultraviolet agent: 0.1~1.0%.

4. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S2, the antioxidant includes antioxidant A and antioxidant B, wherein: Antioxidant A is 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane; Antioxidant B is tris(2,4-di-tert-butylphenyl)phosphite; The mass percentage of each substance is: Antioxidant A: Antioxidant B = 1: (0.2-10); (Random copolymer of propylene and ethylene + all additives): (Antioxidant A + Antioxidant B) = 100: (0.1~1).

5. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S2, the acid scavenger includes acid scavenger A and acid scavenger B, wherein: Acid scavenger A is calcium stearate; Acid scavenger B is hydrogenated talc; The mass percentage of each substance is: Acid scavenger A: Acid scavenger B = 1: (0.5-1.5); (random copolymer of propylene and ethylene + all additives): (acid scavenger A + acid scavenger B) = 100: (0.1-0.2).

6. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S2, the nucleating agent includes nucleating agent A, nucleating agent B and nucleating agent C, wherein: Nucleating agent A: methylene bis(2,4-di-tert-butylphenyl)aluminum phosphate; Nucleating agent B: di-(3,4-dimethylbenzylidene) sorbitol; Nucleating agent C: di(p-methylbenzylidene)xylitol; The mass percentage of each substance is: Nucleating agent A: nucleating agent B: nucleating agent C = (0.1-1): (0.1-1): (0.1-1); (Random copolymer of propylene and ethylene + all additives): (nucleating agent A + nucleating agent B + nucleating agent C) = 100: (0.1 ~ 0.8).

7. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S2, the anti-ultraviolet agent is 2-hydroxy-4-n-octyloxybenzophenone; The mass percentage of each substance is: (Random copolymer of propylene and ethylene + all additives): anti-ultraviolet agent = 100: (0.1 ~ 1.0).

8. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S2, the mixing process is: the propylene and ethylene random copolymer, antioxidant, acid scavenger, nucleating agent and anti-ultraviolet agent are first mixed at a low speed for 0.5 to 1 minute in a high-speed mixer at normal temperature and pressure, then mixed at a high speed for 0.5 to 3 minutes, and finally mixed at a low speed for 0.5 to 1 minute to discharge.

9. The method for preparing a polypropylene resin for manufacturing a weather-resistant solar back sheet according to claim 1, characterized in that: In step S3, the extrusion granulation process is as follows: the mixture of the mixed propylene and ethylene random copolymer and all additives is heated, sheared and mixed by a twin-screw extruder, the screw aspect ratio is ≥30, the melt temperature is controlled at ≥170°C, and then the mixture melt is extruded from the die hole of the die head and then pulled into strips, cooled in a water tank, and then blown dry or self-dehydrated, and cut into particles by a pelletizer.

10. A polypropylene resin for the manufacture of weather-resistant solar backsheets prepared by the preparation method according to claim 1, characterized in that: It has good aging resistance and UV resistance. It can still maintain more than 60% of its mechanical properties after long-term UV exposure of ≥1500 hours, which can meet the production and use requirements of weather-resistant solar backsheets.

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