Fluororesin composition and application thereof

Abstract

The invention discloses a fluororesin composition. The fluororesin composition comprises an ultraviolet absorption auxiliary agent as shown in a structural formula (1) and fluororesin. The ultraviolet absorption auxiliary agent has a fluorine-containing structural unit and an ultraviolet absorption structural unit, so that the ultraviolet absorption auxiliary agent can absorb ultraviolet rays and has good compatibility with fluororesin. When the fluororesin composition provided by the invention is used for preparing a film, the ultraviolet absorption auxiliary agent does not migrate and separate out.

Description

Technical Field

[0001] The present invention relates to the field of fluororesins, and specifically to a fluororesin composition and its application. More specifically, the fluororesin composition includes an ultraviolet absorption aid, which has a fluorine-containing structural unit and an ultraviolet absorption structural unit, and can absorb ultraviolet rays while having good compatibility with the fluororesin. Background Art

[0002] Fluorinated films have very broad application space in the film material field due to their excellent weather resistance, corrosion resistance and light transmittance, and are applied in fields such as solar cell protective films, chip packaging, food and drug packaging films, agricultural greenhouse films, building films, etc.

[0003] Ultraviolet resistance is an important evaluation index for film performance. Generally, the ultraviolet resistance of the film is achieved by adding organic or inorganic ultraviolet blocking agents. However, there are usually many problems with externally added ultraviolet blocking agents. Inorganic ultraviolet blocking aids generally have poor compatibility with the resin matrix, are prone to agglomeration, have poor dispersibility, affect the light transmittance of the film, and have poor uniformity of ultraviolet resistance; fluororesins have low polarity and poor compatibility with conventional organic ultraviolet blocking aids, and organic ultraviolet blocking agents are prone to migration during the processing process, resulting in poor ultraviolet resistance performance.

[0004] Patent WO2016046300A1 discloses a fluoropolymer composition, which provides a fluororesin with a CTFE content of 53-65% in the copolymer structure and a melting point not higher than 210°C by reducing the crystallinity of ETFE / ECTFE, improving the dispersibility of the organic ultraviolet blocking agent in the resin, and ensuring high transparency and low haze after film formation. However, reducing the crystallinity of ETFE / ECTFE will cause a certain degree of decline in the main properties of the fluorine film and reduce the application range of the fluorine film.

[0005] Patent CN115160680B discloses a fluoroplastic film for encapsulating ultra-weather-resistant and high-cutoff photovoltaic modules. The film is composed of ethylene-tetrafluoroethylene copolymer, surface organically coated inorganic nano ultraviolet absorber, organic ultraviolet absorber, antioxidant and light stabilizer. The surface organically coated inorganic nano ultraviolet absorber is inorganic nano zinc oxide coated with polymethyl methacrylate, effectively solving the problem of difficult dispersion of solid-phase inorganic nano-sized particles. Due to the high-efficiency ultraviolet absorption of the organic ultraviolet absorber, a certain proportion of organic ultraviolet absorber still needs to be added in the formula, and there is still a precipitation problem in the processing of ETFE films. Summary of the Invention

[0006] To solve the above problems, the inventors of the present invention prepared an ultraviolet absorption aid for oligomers by subjecting a fluoroolefin and an olefin containing an organic ultraviolet functional group to a two-step telomerization reaction. The ultraviolet absorption aid has good compatibility with fluororesin, is not prone to migration during the processing, and has excellent ultraviolet barrier performance after film formation.

[0007] The technical solution provided by the present invention is as follows:

[0008] The present invention provides a fluororesin composition, and the fluororesin composition includes an ultraviolet absorption aid represented by the structural formula (1),

[0009]

[0010] wherein, 20 ≤ m ≤ 100, 2 ≤ n ≤ 20,

[0011] A is a fluorine-containing structural unit, selected from CFClCF 2 、CFClCF 2 CH 2 CH 2 、CF 2 CF 2 、CF 2 CF 2 CH 2 CH 2 、CF 2 CH 2 and the like,

[0012] R 1 、R 2 are independently selected from H, F, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl,

[0013] R 3 is selected from H, F, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl,

[0014] R 4 is selected from (CH 2 ) n1 COOR 5 、(CH 2 ) n1 OR 5 、(CH 2 ) n1 R 5 、O(CH 2 ) n1 COOR 5 、O(CH2 ) n1 OR 5 、O(CH 2 ) n1 R 5 where 0 ≤ n 1 ≤ 4,

[0015] R 5 is selected from one of the compounds represented by Structural Formula (2) or the compounds represented by Structural Formula (3),

[0016]

[0017] wherein, X 1 、X 2 、X 3 、Y 1 are independently selected from H, OH, F, Cl, C 1 -C 2 alkyl, C 1 -C 2 haloalkyl.

[0018] Furthermore, A is a fluorine-containing structural unit, selected from one of CFClCF 2 CH 2 CH 2 、CF 2 CF 2 CH 2 CH 2 ; R 1 、R 2 are independently selected from H, F, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl; R 3 is selected from H, F, C 1 -C 2 alkyl, C 1 -C 2 haloalkyl; R 4 is selected from (CH 2 )n 1 COOR 5 、(CH 2 )n 1 OR 5 、O(CH 2 )n 1 COOR 5 、O(CH 2 )n 1 OR 5 where 0 ≤ n 1 ≤ 2; R 5 is the compound represented by Structural Formula (2), wherein X1 、X 2 、X 3 is independently selected from H, OH, F, Cl.

[0019] The ultraviolet absorption aid described in the present invention is prepared by two-step telomerization, and the preparation method includes:

[0020] S1: Add the olefin monomer corresponding to the A fluorine-containing structural unit, carbon tetrachloride, acetonitrile, and benzoyl peroxide (hereinafter referred to as BPO) into the reaction equipment, and react at 80-120 °C for 8-16 h;

[0021] S2: Add the olefin monomer containing an organic ultraviolet functional group into the reaction equipment, react for 6-12 h, and remove the solvent after the reaction to obtain the ultraviolet absorption aid.

[0022] The olefin monomer containing an organic ultraviolet functional group described in the present invention is shown in structural formula (4),

[0023]

[0024] wherein, R 1 、R 2 are independently selected from H, F, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl,

[0025] R 3 is selected from H, F, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl,

[0026] R 4 is selected from (CH 2 ) n1 COOR 5 、(CH 2 ) n1 OR 5 、(CH 2 ) n1 R 5 、O(CH 2 ) n1 COOR 5 、O(CH 2 ) n1 OR 5 、O(CH 2 ) n1 R 5 , where 0 ≤ n 1 ≤ 4,

[0027] R 5One selected from the compounds represented by Structural Formula (2) or the compounds represented by Structural Formula (3),

[0028]

[0029] wherein, X 1 、X 2 、X 3 、Y 1 are independently selected from H, OH, F, Cl, C 1 -C 2 alkyl, C 1 -C 2 haloalkyl.

[0030] Furthermore, R 1 、R 2 are independently selected from H, F, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl; R 3 is selected from H, F, C 1 -C 2 alkyl, C 1 -C 2 haloalkyl; R 4 is selected from (CH 2 )n 1 COOR 5 、(CH 2 )n 1 OR 5 、O(CH 2 )n 1 COOR 5 、O(CH 2 )n 1 OR 5 , where 0 ≤ n 1 ≤ 2; R 5 is the compound represented by Structural Formula (2), wherein X 1 、X 2 、X 3 are independently selected from H, OH, F, Cl.

[0031] The particle size of the ultraviolet absorption aid described in the present invention is 0.05 - 5 μm. Within this range of particle size, it is beneficial for the ultraviolet absorption aid to be evenly adsorbed on the fluororesin powder, ensuring the film formation uniformity. Preferably, the particle size is 0.3 - 3 μm.

[0032] As an implementation method, if the particle size of the ultraviolet absorption aid is not within the required range, it can be ground to the required particle size range by air flow pulverization.

[0033] The fluororesin composition of the present invention further comprises a fluororesin selected from one of ETFE, ECTFE, PVDF, P(VDF-co-TFE), P(VDF-co-HFP), P(VDF-co-CTFE), P(VDF-TrFE), PTFE, PFA, FEP, PCTFE. Preferably, the fluororesin is selected from one of ETFE and ECTFE.

[0034] The melt index of the fluororesin of the present invention is 4 - 30 g / 10 min. The melt index test conditions for different fluororesins are as follows: PCTFE (265 °C, 21.6 kg), ECTFE (270 °C, 2.16 kg), PVDF (230 °C, 2.16 kg), P(VDF-co-TFE) (230 °C, 2.16 kg), P(VDF-co-HFP) (230 °C, 2.16 kg), P(VDF-co-CTFE) (230 °C, 2.16 kg), P(VDF-TrFE) (230 °C, 2.16 kg), ETFE (300 °C, 5 kg), PFA (400 °C, 5 kg), FEP (372 °C, 5 kg).

[0035] If the melt index of the fluorine index is too large or too small, it is not conducive to film formation.

[0036] The mass ratio of the ultraviolet absorption aid to the fluororesin in the present invention is 1 - 16%. Preferably, the mass ratio is 2 - 10%. If the mass ratio is too high, it will affect the mechanical properties of the fluorine film after film formation; if the mass ratio is too low, the ultraviolet absorption performance of the fluorine film after film formation is poor.

[0037] The present invention also provides an application of the fluororesin composition. The fluororesin composition is used as a raw material for preparing an ultraviolet-resistant film. Further, it is used for preparing an ultraviolet-resistant transparent film.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows: Compared with conventional small-molecule organic ultraviolet absorbers, the ultraviolet absorption aid in the fluororesin composition of the present invention has good compatibility with the fluororesin. Coupled with the large molecular weight of the ultraviolet absorption aid of the present invention, it is not easy to migrate during the processing, ensuring the ultraviolet barrier property of the film. In addition, by controlling the particle size of the ultraviolet absorption aid of the present invention, it can be ensured that the ultraviolet absorption aid is evenly adsorbed on the fluororesin powder, ensuring the film formation uniformity. Detailed Embodiments

[0039] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternative solutions, improvement solutions, and equivalent solutions that may be included within the scope of the claims.

[0040] The ultraviolet absorption rate test method of the present invention: Use an ultraviolet spectrophotometer to test the ultraviolet absorption rate of a 50-μm thick film.

[0041] Example 1

[0042] Add 9.2 kg of chlorotrifluoroethylene, 15 kg of carbon tetrachloride, 10 kg of acetonitrile, and 0.5 kg of BPO to the reaction vessel respectively, react at 110 °C for 14 h, then continue to add 6 kg of olefin monomer S1 with an organic ultraviolet functional group to the reaction vessel, and continue to react for 10 h. After the reaction is completed, evaporate the solvent to dryness, and grind the product into a powder with a particle size of 1 μm by air flow pulverization to obtain the ultraviolet absorption aid T1.

[0043] The structure of S1 is as follows:

[0044]

[0045] The structure of the ultraviolet absorption aid T1 is as follows:

[0046]

[0047] R 5 The structural formula is as follows:

[0048]

[0049] 40 ≤ m ≤ 60, 8 ≤ n ≤ 12.

[0050] The synthesis route of S1 is as follows: Add a small amount of polymerization inhibitor hydroquinone and zeolite to (6Z)-6-tridecenoic acid, add carbonic diamine as a catalyst, add thionyl chloride at 10 °C, and gradually raise the temperature to 60 °C when the reaction slows down, and continue to react for about 1 h. The crude product is distilled under normal pressure to obtain (6Z)-6-tridecanoyl chloride. (6Z)-6-tridecanoyl chloride reacts with equimolar 2,2′,4-trihydroxybenzophenone in anhydrous pyridine at 60 °C for 4 h, and the product is purified to obtain S1. The synthesis of S2-S10 refers to the S1 route.

[0051] Mix 20 kg of ECTFE resin with a melt index of 19 g / 10 min and 1 kg of ultraviolet absorption aid T1 in a high-speed mixer, and add the uniformly mixed material to a single-screw extruder for processing to prepare a 50-μm thick film, and test the ultraviolet absorption rate of the prepared film.

[0052] Example 2

[0053] 12 kg of chlorotrifluoroethylene, 3.5 kg of ethylene, 30 kg of carbon tetrachloride, 10 kg of acetonitrile, and 0.8 kg of BPO were added to a reaction vessel and reacted at 120 °C for 16 h. Then, 24.1 kg of an olefin monomer S2 with an organic ultraviolet functional group was added to the reaction vessel and the reaction was continued for 12 h. After the reaction, the solvent was evaporated to dryness, and the product was pulverized by air flow and ground into a powder with a particle size of 1 μm to obtain an ultraviolet absorption aid T2.

[0054] The structure of S2 is as follows:

[0055]

[0056] The structure of the ultraviolet absorption aid T2 is as follows:

[0057]

[0058] R 5 The structural formula is as follows:

[0059]

[0060] 20 ≤ m ≤ 40, 2 ≤ n ≤ 4.

[0061] 20 kg of PCTFE resin with a melt index of 12 g / 10 min and 3 kg of the ultraviolet absorption aid T2 were mixed in a high-speed mixer, and the uniformly mixed material was added to a single-screw extruder for processing to prepare a 50-μm-thick film. The prepared film was tested for ultraviolet absorption rate.

[0062] Example 3

[0063] 8 kg of vinylidene fluoride, 25 kg of carbon tetrachloride, 8 kg of acetonitrile, and 1 kg of BPO were added to a reaction vessel and reacted at 80 °C for 8 h. Then, 9.5 kg of an olefin monomer S3 with an organic ultraviolet functional group was added to the reaction vessel and the reaction was continued for 10 h. After the reaction, the solvent was evaporated to dryness, and the product was pulverized by air flow and ground into a powder with a particle size of 0.05 μm to obtain an ultraviolet absorption aid T3.

[0064] The structure of S3 is as follows:

[0065]

[0066] The structure of the ultraviolet absorption aid T3 is as follows:

[0067]

[0068] R 5 The structural formula is as follows:

[0069]

[0070] 80 ≤ m ≤ 100, 10 ≤ n ≤ 20.

[0071] Mix 15 kg of PVDF resin with a melt index of 4 g / 10 min and 1.2 kg of ultraviolet absorption aid T3 in a high-speed mixer. Add the uniformly mixed material into a single-screw extruder for processing to prepare a 50-μm thick film, and test the ultraviolet absorption rate of the prepared film.

[0072] Example 4

[0073] Add 10 kg of tetrafluoroethylene, 3.2 kg of ethylene, 18 kg of carbon tetrachloride, 6 kg of acetonitrile, and 0.6 kg of BPO into a reaction vessel, react at 90 °C for 12 h, then continue to add 20.2 kg of olefin monomer S4 with an organic ultraviolet functional group into the reaction vessel, and continue to react for 8 h. After the reaction is completed, evaporate the solvent, and grind the product into a powder with a particle size of 2 μm by air-flow crushing to obtain ultraviolet absorption aid T4.

[0074] The structure of S4 is as follows:

[0075]

[0076] The structure of ultraviolet absorption aid T4 is as follows:

[0077]

[0078] R 5 The structural formula is as follows:

[0079]

[0080] 20 ≤ m ≤ 30, 8 ≤ n ≤ 12.

[0081] Mix 25 kg of ETFE resin with a melt index of 30 g / 10 min and 0.25 kg of ultraviolet absorption aid T4 in a high-speed mixer. Add the uniformly mixed material into a single-screw extruder for processing to prepare a 50-μm thick film, and test the ultraviolet absorption rate of the prepared film.

[0082] Example 5

[0083] Add 6 kg of tetrafluoroethylene, 25 kg of carbon tetrachloride, 8 kg of acetonitrile, and 0.5 kg of BPO into a reaction vessel, react at 100 °C for 16 h, then continue to add 9 kg of olefin monomer S5 with an organic ultraviolet functional group into the reaction vessel, and continue to react for 6 h. After the reaction is completed, evaporate the solvent, and grind the product into a powder with a particle size of 5 μm by air-flow crushing to obtain ultraviolet absorption aid T5.

[0084] The structure of S5 is as follows:

[0085]

[0086] The ultraviolet absorption aid T5 has the following structure:

[0087]

[0088] R 5 The structural formula is as follows:

[0089]

[0090] 40 ≤ m ≤ 60, 10 ≤ n ≤ 20

[0091] Mix 25 kg of PFA resin with a melt index of 8 g / 10 min and 1.3 kg of ultraviolet absorption aid T5 in a high-speed mixer. Add the uniformly mixed material into a single-screw extruder for processing to prepare a 50-μm thick film, and test the ultraviolet absorption rate of the prepared film.

[0092] Example 6

[0093] Add 8.5 kg of tetrafluoroethylene, 2.2 kg of ethylene, 30 kg of carbon tetrachloride, 10 kg of acetonitrile, and 1.1 kg of BPO into the reaction vessel, react at 110 °C for 10 h, then continue to add 1.5 kg of olefin monomer S6 with an organic ultraviolet functional group into the reaction vessel, and continue to react for 12 h. After the reaction, evaporate the solvent, and grind the product by air flow pulverization to a particle size of 5 μm powder to obtain the ultraviolet absorption aid T6.

[0094] The structure of S6 is as follows:

[0095]

[0096] The ultraviolet absorption aid T6 has the following structure:

[0097]

[0098] R 5 The structural formula is as follows:

[0099]

[0100] 80 ≤ m ≤ 100, 8 ≤ n ≤ 12.

[0101] Mix 20 kg of FEP resin with a melt index of 25 g / min and 2.2 kg of ultraviolet absorption aid T6 in a high-speed mixer. Add the uniformly mixed material into a single-screw extruder for processing to prepare a 50-μm thick film, and test the ultraviolet absorption rate of the prepared film.

[0102] Example 7

[0103] Add 10 kg of tetrafluoroethylene, 15 kg of carbon tetrachloride, 8 kg of acetonitrile, and 0.6 kg of BPO into the reaction vessel respectively, react at 120 °C for 12 h, then continue to add 10.5 kg of olefin monomer S7 with an organic ultraviolet functional group into the reaction vessel, and continue to react for 10 h. After the reaction is completed, evaporate the solvent to dryness, and grind the product into a powder with a particle size of 0.1 μm by air flow pulverization to obtain the ultraviolet absorption auxiliary agent T7.

[0104] The structure of S7 is as follows:

[0105]

[0106] The structure of the ultraviolet absorption auxiliary agent T7 is as follows:

[0107]

[0108] R 5 The structural formula is as follows:

[0109]

[0110] 20 ≤ m ≤ 40, 10 ≤ n ≤ 20.

[0111] Mix 20 kg of P(VDF-co-TFE) resin with a melt index of 14 g / 10 min and 0.3 kg of the ultraviolet absorption auxiliary agent T7 in a high-speed mixer, add the uniformly mixed material into a single-screw extruder for processing to prepare a 50-μm-thick film, and test the ultraviolet absorption rate of the prepared film.

[0112] Example 8

[0113] Add 12 kg of vinylidene fluoride, 25 kg of carbon tetrachloride, 10 kg of acetonitrile, and 0.7 kg of BPO into the reaction vessel respectively, react at 115 °C for 12 h, then continue to add 5.3 kg of olefin monomer S8 with an organic ultraviolet functional group into the reaction vessel, and continue to react for 10 h. After the reaction is completed, evaporate the solvent to dryness, and grind the product into a powder with a particle size of 0.5 μm by air flow pulverization to obtain the ultraviolet absorption auxiliary agent T8.

[0114] The structure of S8 is as follows:

[0115]

[0116] The structure of the ultraviolet absorption auxiliary agent T8 is as follows:

[0117]

[0118] R 5 The structural formula is as follows:

[0119]

[0120] 40 ≤ m ≤ 60, 8 ≤ n ≤ 12.

[0121] 16 kg of P(VDF-co-CTFE) resin with a melt index of 15 g / 10 min and 1.5 kg of ultraviolet absorption aid T8 were mixed in a high-speed mixer. The uniformly mixed material was added to a single-screw extruder for processing to prepare a 50-μm thick film, and the prepared film was tested for ultraviolet absorption rate.

[0122] Example 9

[0123] 10 kg of vinylidene fluoride, 30 kg of carbon tetrachloride, 10 kg of acetonitrile, and 1.1 kg of BPO were added to a reaction vessel and reacted at 110 °C for 10 h. Then, 3.7 kg of olefin monomer S9 with an organic ultraviolet functional group was continuously added to the reaction vessel and reacted for another 12 h. After the reaction, the solvent was evaporated to dryness, and the product was ground into a powder with a particle size of 5 μm by air-flow pulverization to obtain ultraviolet absorption aid T9.

[0124] The structure of S9 is as follows:

[0125]

[0126] The structure of ultraviolet absorption aid T9 is as follows:

[0127]

[0128] R 5 The structural formula is as follows:

[0129]

[0130] 80 ≤ m ≤ 100, 10 ≤ n ≤ 20.

[0131] 25 kg of P(VDF-co-HFP) resin with a melt index of 20 g / 10 min and 2.5 kg of ultraviolet absorption aid T9 were mixed in a high-speed mixer. The uniformly mixed material was added to a single-screw extruder for processing to prepare a 50-μm thick film, and the prepared film was tested for ultraviolet absorption rate.

[0132] Example 10

[0133] 8 kg of vinylidene fluoride, 18 kg of carbon tetrachloride, 6 kg of acetonitrile, and 0.6 kg of BPO were added to a reaction vessel and reacted at 120 °C for 12 h. Then, 10 kg of olefin monomer S10 with an organic ultraviolet functional group was continuously added to the reaction vessel and reacted for another 10 h. After the reaction, the solvent was evaporated to dryness, and the product was ground into a powder with a particle size of 0.1 μm by air-flow pulverization to obtain ultraviolet absorption aid T10.

[0134] The structure of S10 is as follows:

[0135]

[0136] The structure of the ultraviolet absorption aid T10 is as follows:

[0137]

[0138] R 5 The structural formula is as follows:

[0139]

[0140] 20 ≤ m ≤ 40, 8 ≤ n ≤ 12

[0141] 20 kg of P(VDF-co-TrFE) resin with a melt index of 22 g / 10 min and 0.6 kg of the ultraviolet absorption aid T10 were mixed in a high-speed mixer, and the uniformly mixed material was added to a single-screw extruder for processing to prepare a 50-μm-thick film. The prepared film was subjected to ultraviolet absorption rate testing.

[0142] Comparative Example 1

[0143] 20 kg of ECTFE resin with a melt index of 19 g / 10 min and 1 kg of the ultraviolet absorption aid 2,2’,4,4’-tetrahydroxybenzophenone were mixed in a high-speed mixer, and the uniformly mixed material was added to a single-screw extruder for processing to prepare a 50-μm-thick film. The prepared film was subjected to ultraviolet absorption rate testing.

[0144] Comparative Example 2

[0145] Same as Example 1, except that: the ultraviolet absorption aid product was ground to a powder with a particle size of 20 μm by air-flow pulverization.

[0146] 20 kg of ECTFE resin with a melt index of 19 g / min and 1 kg of the ultraviolet absorption aid were mixed in a high-speed mixer, and the uniformly mixed material was added to a single-screw extruder for processing to prepare a 50-μm-thick film. The prepared film was subjected to ultraviolet absorption rate testing.

[0147] Table 1 shows the ultraviolet absorption rate test data of the film, with the wavelength ranging from 290 to 440 nm.

[0148] Table 1 Ultraviolet Absorption Rate Test Data of the Film

[0149]

[0150] From the comparison between the examples and the comparative examples, the thin film prepared by adding the ultraviolet absorption aid of the present invention has a high ultraviolet absorption rate. In Comparative Example 1, the small molecule ultraviolet absorption aid 2,2’,4,4’-tetrahydroxybenzophenone has a low compatibility with fluororesin, and its small molecular weight causes precipitation during film formation, resulting in a significant decrease in the ultraviolet absorption rate of the fluorine film. In Comparative Example 2, the particle size of the ultraviolet absorption aid is 20um, which is relatively large and cannot be evenly adsorbed on the surface of the fluororesin, causing a decrease in the ultraviolet absorption rate of the fluorine film. After the fluorine film is irradiated with an ultraviolet lamp at 300 kwh / m 2 After irradiation, the ultraviolet absorption rates of the example and Comparative Example 2 decreased slightly to a certain extent, while the ultraviolet absorption rate of Comparative Example 1 decreased by 6.1%, indicating that the organic small molecule ultraviolet absorber precipitated during the aging process, resulting in a significant decrease in the ultraviolet absorption rate.

Claims

1. A fluororesin composition, characterized in that: it comprises an ultraviolet absorption auxiliary agent shown in structural formula (1), wherein, 20 ≤ m ≤ 100, 2 ≤ n ≤ 20, A is a fluorine-containing structural unit selected from CFClCF 2 、CFClCF 2 CH 2 CH 2 、CF 2 CF 2 、CF 2 CF 2 CH 2 CH 2 、CF 2 CH 2 ; one of them, R 1 、R 2 are independently selected from H, F, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl. R 3 selected from H, F, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, R 4 selected from (CH 2 ) n1 COOR 5 、(CH 2 ) n1 OR 5 、(CH 2 ) n1 R 5 、O(CH 2 ) n1 COOR 5 、O(CH 2 ) n1 OR 5 、O(CH 2 ) n1 R 5 where 0 ≤ n 1 ≤ 4, R 5 selected from one of the compounds represented by the structural formula (2) or the compounds represented by the structural formula (3), Among them, X 1 , X 2 , X 3 , Y 1 are independently selected from H, OH, F, Cl, C 1 -C 2 alkyl, C 1 -C 2 haloalkyl.

2. The fluororesin composition according to claim 1, characterized in that: A is a fluorine-containing structural unit selected from CFClCF 2 CH 2 CH 2 CF 2 CF 2 CH 2 CH 2 and one of them R 1 and R 2 are independently selected from H, F, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, R 3 selected from H, F, C 1 -C 2 alkyl, C 1 -C 2 haloalkyl, R 4 Selected from (CH 2 )n 1 COOR 5 、(CH 2 )n 1 OR 5 、O(CH 2 )n 1 COOR 5 、O(CH 2 )n 1 OR 5 where 0 ≤ n 1 ≤ 2, R 5 is the compound shown in structural formula (2), where X 1 , X 2 , X 3 are independently selected from H, OH, F, Cl.

3. The fluororesin composition according to any one of claims 1-2, characterized in that: the particle size of the ultraviolet absorption auxiliary agent is 0.05-5 μm.

4. The fluororesin composition according to claim 3, characterized in that: the particle size of the ultraviolet absorption auxiliary agent is 0.3-3 μm.

5. The fluororesin composition according to claim 1, characterized in that: it further comprises a fluororesin, and the fluororesin is selected from one of ETFE, ECTFE, PVDF, P(VDF-co-TFE), P(VDF-co-HFP), P(VDF-co-CTFE), P(VDF-TrFE), PFA, FEP, PCTFE.

6. The fluororesin composition according to claim 5, characterized in that: the fluororesin is selected from one of ETFE and ECTFE.

7. The fluororesin composition according to claim 5, characterized in that: the melt index of the fluororesin is 4-30 g / 10 min.

8. The fluororesin composition according to claim 5, characterized in that: the mass ratio of the ultraviolet absorption auxiliary agent to the fluororesin is 1-16%.

9. The fluororesin composition according to claim 8, characterized in that: the mass ratio of the ultraviolet absorption auxiliary agent to the fluororesin is 2-10%.

10. The application of the fluororesin composition according to any one of claims 1-9, characterized in that: the fluororesin composition is used as a raw material for preparing an ultraviolet-resistant film.

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