Composite light stabilizer as well as preparation method and application thereof

Abstract

The invention relates to a composite light stabilizer and a preparation method and application thereof, the composite light stabilizer comprises a light stabilizer, an ultraviolet light cross-linking agent, a nucleating agent and rubber particles with a cross-linked structure, the total amount of the nucleating agent and the rubber particles with the cross-linked structure in the composite light stabilizer is 0.2-2 parts by mass relative to 1 part by mass of the light stabilizer, and the content of the ultraviolet light cross-linking agent and the rubber particles with the cross-linked structure is 0.5-1 part by mass. The content of the ultraviolet light cross-linking agent is 0.5 to 3.5 parts. The mechanical property of the modified resin film (such as a mulching film or a cotton packaging film) is basically kept unchanged, the loss rate of the mechanical property is low along with the increase of the ultraviolet irradiation time, the mechanical property of some film materials is even slowly improved, the mechanical property of the film materials during recycling is effectively guaranteed, the method can be widely applied to mechanical recycling of agricultural films, the recycling rate of the agricultural films is improved, and the cost is reduced. The method is of great significance to reduction of white pollution.

Description

Technical Field

[0001] The present invention relates to the field of light stabilizers, and more particularly to a composite light stabilizer and a preparation method and application thereof. Background Art

[0002] Data from the National Bureau of Statistics show that in 2015, the area covered by plastic film in my country reached 275 million mu, and the amount used reached 1.455 million tons. It is predicted that by 2024, the area covered by plastic film in my country will reach 330 million mu, and the amount used will exceed 2 million tons. Such large-scale use of plastic film has both advantages and disadvantages. On the one hand, it has played a huge role in improving the quality and efficiency of agriculture, but on the other hand, it has also caused serious harm to the soil environment, resulting in the "white revolution" deriving from negative products such as "white pollution". Abandoned agricultural film fragments enter the cultivated soil, affecting the permeability of the soil, reducing the soil moisture content, weakening the drought resistance, causing secondary salinization, causing soil compaction and reduced fertility, hindering the absorption of water by crops and the growth of root systems, causing the quality of cultivated land to gradually deteriorate, and causing serious damage to the agricultural ecological environment. The residual film is abandoned in the fields and blown by the wind to the front and back of houses, treetops in the fields, and river ponds, affecting the appearance of the village. How to keep the thickness of the mulch film basically unchanged, but significantly improve its weather resistance and tear resistance, so as to increase the recycling rate of the mulch film and reduce "white pollution" has become an important issue that needs to be solved urgently.

[0003] In the prior art, light stabilizers are usually used to modify the matrix to improve the strength of the mulch film material after use and increase the recycling rate. However, simply adding light stabilizers will lose some of the mechanical properties of the material, resulting in a low recycling rate of agricultural films after use.

[0004] Therefore, how to provide a composite light stabilizer so that the mechanical properties of the modified polyolefin film remain basically unchanged, and further, how to reduce the loss rate of mechanical properties with increasing UV irradiation time, ensure the mechanical properties of the film when it is recycled, and improve the recovery rate of the film, is a technical problem that needs to be solved at present. Summary of the invention

[0005] In view of the above technical problems, the purpose of the present invention is to provide a composite light stabilizer and a preparation method and application thereof. The present invention provides a composite light stabilizer. The mechanical properties of the resin film (such as ground film or cotton packaging film) modified by the composite light stabilizer remain basically unchanged. With the increase of ultraviolet light irradiation time, the loss rate of its mechanical properties is low, and some even improve slowly, which effectively ensures the mechanical properties of the film material when it is recycled. It can be widely used in mechanical recycling of agricultural films, improve the recovery rate of agricultural films, and is of great significance to reducing "white pollution".

[0006] The first aspect of the present invention is to provide a composite light stabilizer, comprising a light stabilizer, an ultraviolet light crosslinking agent, a nucleating agent and rubber particles with a crosslinked structure. In parts by mass, relative to 1 part of the light stabilizer, the total amount of the nucleating agent and the rubber particles with a crosslinked structure in the composite light stabilizer is 0.2 to 2 parts, and the content of the ultraviolet light crosslinking agent is 0.5 to 3.5 parts.

[0007] In a preferred embodiment of the present invention, the mass ratio of the rubber particles to the nucleating agent is (3-7): (7-3).

[0008] In a preferred embodiment of the present invention, the nucleating agent is selected from at least one of sorbitol derivative nucleating agents, organic carboxylic acid nucleating agents, organic carboxylate nucleating agents, and organic phosphate nucleating agents; more preferably, the nucleating agent is selected from at least one of nucleating agent NA11, nucleating agent NA21, and nucleating agent 20E.

[0009] In a preferred embodiment of the present invention, the rubber particles having a cross-linked structure have at least one of the following characteristics:

[0010] The average particle size of the rubber particles is 0.02 to 2 microns, preferably 0.1 to 1 micron, more preferably 0.2 to 0.5 micron; and / or,

[0011] The rubber particles are spherical; and / or,

[0012] The rubber particles have a gel content of 60 wt % or more, preferably 80 wt % or more.

[0013] In a preferred embodiment of the present invention, the rubber particles are at least one of the following rubber particles having a cross-linked structure: natural rubber, styrene-butadiene rubber, carboxylated styrene-butadiene rubber, nitrile rubber, carboxylated nitrile rubber, chloroprene rubber, polybutadiene, acrylic rubber, styrene-butadiene rubber, isoprene rubber, butyl rubber, ethylene-propylene rubber, polysulfide rubber, acrylate-butadiene rubber, polyurethane rubber, fluororubber, and ethylene-vinyl acetate rubber.

[0014] The rubber particles with cross-linked structure described in the present invention can be prepared by the method of patent CN1402752, that is, a rubber latex containing uncross-linked rubber particles with a particle size of 20-2000nm is added with a cross-linking agent such as TMPTA, irradiated by a high-energy ray source, and spray-dried to prepare the rubber particles. The obtained cross-linked rubber particles are easy to disperse and can be used as a carrier to assist the nucleating agent and the light stabilizer to be more evenly dispersed in the matrix resin, thereby significantly improving the comprehensive mechanical properties of the resin composition and meeting the requirements in the cotton packaging process. During the transportation and storage of cotton bales, due to the combined effects of ultraviolet light and heat, the polyethylene molecular chain breaks and a large number of free radicals are generated. At this time, the ultraviolet cross-linking agent in the composition can not only absorb free radicals, but also react with the cross-linked rubber particles to promote the generation of the cross-linked structure, so that the mechanical properties of the composition can be effectively maintained, so that the packaging film can meet the requirements of high strength and high weather resistance during storage and transportation.

[0015] In the present invention, the nucleating agent and the rubber particles having a cross-linked structure may be added to the resin composition as separate raw materials, or a commercial product containing both may be used.

[0016] In another preferred embodiment of the present invention, the rubber particles and the nucleating agent are derived from a resin nucleating agent containing both the rubber particles and the nucleating agent; preferably, the resin nucleating agent is selected from at least one of VP101B, VP101C, and VP801E.

[0017] In a preferred embodiment of the present invention, the ultraviolet crosslinking agent is selected from at least one of the crosslinking agents capable of undergoing isocyanate internal crosslinking and / or ketone hydrazine room temperature self-crosslinking reaction, preferably at least one of the crosslinking agents capable of undergoing isocyanate internal crosslinking and / or ketone hydrazine room temperature self-crosslinking reaction at room temperature, such as 22-28°C; preferably,

[0018] The ultraviolet crosslinking agent is selected from at least one of trimethylolpropane triacrylate, benzoin, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, diphenyl acetone, α,α-dimethoxy-α-phenylacetophenone, α,α-diethoxyacetophenone, α-hydroxyalkyl phenone, α-aminoalkyl phenone, aromatic acyl phosphine oxide, bisbenzoylphenyl phosphine oxide, benzophenone, 2,4-dihydroxybenzophenone, thiopropoxythioxanthone and isopropylthioxanthone.

[0019] According to the present invention, the light stabilizer can be selected from a wide range. In a preferred embodiment of the present invention, the light stabilizer is selected from at least one of the following light stabilizers:

[0020] Salicylate light stabilizers, benzoate light stabilizers, benzophenone light stabilizers, benzotriazole light stabilizers, triazine light stabilizers, substituted acrylonitrile light stabilizers, oxamide light stabilizers, organic nickel complex light stabilizers, hindered amine light stabilizers;

[0021] Preferably, the light stabilizer is selected from hindered amine light stabilizers, more preferably at least one selected from light stabilizer 944, light stabilizer 362 and light stabilizer 622, and even more preferably light stabilizer 944 and light stabilizer 622.

[0022] The light stabilizing agent of the present invention may also contain at least one auxiliary agent commonly used in plastic processing, and the dosage thereof is a conventional dosage or may be adjusted according to actual requirements.

[0023] The second aspect of the present invention is to provide a method for preparing the composite light stabilizer described in the first aspect, comprising the step of mixing raw materials including the light stabilizer, an ultraviolet light crosslinking agent, a nucleating agent and rubber particles having a crosslinking structure.

[0024] The mixing is a conventional technical means in the art, including but not limited to mixing by high-speed stirring.

[0025] The composite light stabilizer of the present invention is prepared by physically blending all components including commercially available light stabilizers, ultraviolet light crosslinking agents, nucleating agents and rubber particles with crosslinking structures, has good compatibility with polymers and their additives, and has light stability, thermal stability and chemical stability.

[0026] The method of the invention is simple and easy to implement, has universal applicability, and is easy to realize industrial production.

[0027] The third aspect of the present invention is to provide a use of the composite light stabilizer described in the first aspect or the composite light stabilizer obtained by the preparation method described in the second aspect in a resin composition.

[0028] The composite light stabilizer is suitable for modifying base resins such as polyethylene and polypropylene, and is particularly suitable for ground films with a thickness of about 10 μm and for applications under extreme heat and ultraviolet conditions.

[0029] The fourth aspect of the present invention is to provide a resin composition comprising a base resin, a composite light stabilizer and an optional auxiliary agent;

[0030] The composite light stabilizer is selected from the composite light stabilizer described in the first aspect or the composite light stabilizer obtained by the preparation method described in the second aspect; preferably,

[0031] Based on parts by mass, relative to 100 parts of the matrix resin, the content of the composite light stabilizer is 0.3 - 2 parts; and / or, the matrix resin is selected from polyethylene; and / or, the additive is selected from antioxidants.

[0032] The fifth aspect of the present invention is to provide a method for preparing the resin composition described in the fourth aspect, which includes melt-blending raw materials including the matrix resin, the composite light stabilizer, and optional additives to obtain the resin composition.

[0033] The resin composition of the present invention is prepared by using the common melt-blending method in rubber and plastic processing, and melting and blending the raw material components including the matrix resin described above through common rubber and plastic blending equipment at one time.

[0034] During the preparation process, the blending temperature of the materials corresponds to the normal processing temperature of the matrix polyethylene resin and should be selected within the range that can ensure the complete melting of the matrix polyethylene resin without decomposition. According to processing needs, conventional additives for plastic processing can be appropriately added to the blended materials. During the blending process, the above components can be simultaneously added to the melt-blending equipment by metering feeding and other methods for melt-blending; or they can be first uniformly mixed through a general mixing equipment, and then passed through the rubber and plastic blending equipment to obtain the modified resin composition by one-time melt-blending and extrusion.

[0035] The rubber and plastic blending equipment used in the preparation method of the present invention can be an open mill, an internal mixer, a single-screw extruder, a twin-screw extruder, a torque rheometer, etc. The material mixing equipment is selected from common mechanical mixing equipment such as high-speed mixers and kneaders in the field.

[0036] The sixth aspect of the present invention is to provide an application of the resin composition described in the fourth aspect or the resin composition obtained by the preparation method described in the fifth aspect in agricultural films, polyolefin roofing tiles, and polyolefin rotational plastics.

[0037] The resin composition containing the composite light stabilizer of the present invention is prepared by a method of melt-blending all components including the matrix resin and the composite light stabilizer at one time. The preparation method is simple, without blooming or exudation during processing and use; the resin composition containing this composite light stabilizer has light stability, thermal stability, and chemical stability, does not change due to heat during processing and use, and has little thermal volatilization loss; it is hydrolysis-resistant, low in price, and low in cost, and is easy to promote and use. It can be widely applied in the agricultural field, such as greenhouse films, mulch films, winding films, geotextiles, etc., and can also be used in TPO roofing materials, exterior walls of houses, wall panels, polyolefin roofing tiles in the construction field; blinds, polyolefin roofing wall panels, solar energy, sports tiles, and polyolefin molding plastics and rotational plastics, etc.

[0038] The advantages of the present invention are:

[0039] The present invention adopts specific raw material types and proportions to provide a composite light stabilizer. The mechanical properties of the resin film (such as ground film or cotton packaging film) modified by the composite light stabilizer remain basically unchanged. With the increase of ultraviolet light irradiation time, the loss rate of the mechanical properties is low, and some even slowly improve, which effectively ensures the mechanical properties of the film material when it is recycled. The composite light stabilizer can be widely used in mechanical recycling of agricultural films, improve the recycling rate of agricultural films, and is of great significance to reducing "white pollution".

[0040] The inventors of the present invention believe that the above advantages are due to:

[0041] The light stabilizer, ultraviolet crosslinker, nucleator and rubber particles with crosslinked structure in the composite light stabilizer have a synergistic effect. The addition of the nucleator in the composite light stabilizer improves the crystallinity of the resin, accelerates its crystallization rate, reduces the amorphous region, and works synergistically with the light stabilizer and the ultraviolet crosslinker, which is conducive to maintaining the mechanical properties of the material. Under heat and ultraviolet light conditions, the ultraviolet crosslinker can absorb energy of a certain wavelength, generate free radicals, cations, etc., thereby initiating monomer polymerization and crosslinking. Inside the molecule, under the raw materials and proportions of the present invention, crosslinking and degradation are carried out simultaneously, and the free radicals and cations provided by the ultraviolet crosslinker contribute to the crosslinking between the molecular chains, maintain the molecular weight, and thus make the mechanical properties better retainable. With the increase of ultraviolet light exposure time, its mechanical properties are basically not lost, and are basically equivalent to before use, which increases the service life of the matrix material, helps agricultural machinery to be recycled, and improves the recycling efficiency. DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0043] The scope of the present invention is not limited by these embodiments, but is set forth in the appended claims.

[0044] The experimental data in the examples were measured using the following equipment and methods:

[0045] The test of tensile load and nominal strain at break of specimen preparation was carried out in accordance with the national standard GB / T1040.3-2006. The specimen was type 2, with a width of 10 mm, an initial marking distance of 50 mm between the clamps, a test speed (no load) of 500 mm / min, and the specimen was stretched until it broke. The maximum tensile load was measured with an accuracy of 0.01 N. The specimens prepared clearly indicated the specimen number and sampling direction (horizontal or vertical).

[0046] The nominal strain at break is calculated as follows:

[0047] ε=ΔL / L×100

[0048] Where:

[0049] ε——nominal strain at fracture, %;

[0050] ΔL——Increment of the distance between fixtures, in millimeters (mm);

[0051] L——The initial distance between the fixtures, in millimeters (mm).

[0052] The test is carried out in accordance with QB / T1130-1991, with a single specimen test and an accuracy of 0.1N.

[0053] Right-angle tear detection method: refer to QB / T 1130-91 standard for the experiment. The initial distance between the clamps is 55mm, the test speed (no load) is 200mm / min, the sample is stretched until it breaks, and the maximum tensile load is measured with an accuracy of 0.01N. The prepared samples clearly indicate the sample number and sampling direction (horizontal or vertical).

[0054] The prepared tensile and right-angle tearing specimens need to be subjected to artificial ultraviolet aging comparative experiments. The specific conditions of ultraviolet aging are as follows: refer to GB / T16422.3-2014, the light source is a fluorescent ultraviolet lamp, UV-A340 lamp tube, at a wavelength of 340nm, the irradiance is 0.76W / (m 2 ·nm), and UV irradiation was carried out according to the rules of illumination temperature 60℃, radiation time 8h (bright); condensation temperature 50℃, condensation time 4h (dark), and the irradiation time was 288 hours.

[0055] In the following examples, 1076 refers to antioxidant 1076 produced by BASF Chemicals; 168 refers to antioxidant 168 produced by BASF Chemicals; 944 refers to light stabilizer 944 produced by Beijing Tiangang Chemicals;

[0056] VP801E refers to VP801E produced by Sinopec Beijing Research Institute of Chemical Industry, wherein VP801E contains nucleating agent NA11 and EVA rubber particles with a cross-linked structure, the average particle size of the rubber particles is 0.2 microns, and the gel content of the rubber particles is 90wt%; the mass ratio of the rubber particles to the nucleating agent is 3:7.

[0057] In the following Examples 1-6 and Comparative Examples 1-4:

[0058] The process of initial mixing and melt blending of materials is as follows: first weigh all materials according to the proportion, perform preliminary mixing in a high-speed mixer for 20 seconds, and then use a twin-screw extruder for melt blending and granulation. The mixing equipment is a Coperion 35 twin-screw extruder with a speed of 200r / min and a temperature setting of 170°C, 180°C, 190°C, 200°C, 200°C, and 200°C; the obtained pellets are placed in a tray and treated in an oven at 70°C for 4 hours to remove moisture.

[0059] The film was prepared by blow molding: the equipment was a German Colin film blowing machine, the temperatures of each section were set at 160°C, 180°C, 200°C, 210°C, 210°C, 210°C, 210°C, the feed amount was 25%, the winding rate was 10m / min, and the obtained film had a smooth surface, an average width of 22cm, and an average thickness of 10μm.

[0060] Comparative Example 1 and Comparative Example 2

[0061] 1600g of LLDPE resin 1802 provided by Zhenhai Petrochemical was used as the matrix, and 0.80g of antioxidant 1076 and 1.6g of antioxidant 168 produced by BASF Chemical were mixed and melt-blended according to the above conditions. The obtained pellets were used to prepare films by blow molding, and tensile and right-angle tear specimens were prepared, which is Comparative Example 1.

[0062] The obtained comparative example 1 sample was marked as comparative example 2 after artificial ultraviolet accelerated aging.

[0063] Comparative Example 3 and Comparative Example 4

[0064] 1600g of LLDPE resin 1802 provided by Zhenhai Petrochemical was used as the matrix, and 0.80g of antioxidant 1076 produced by BASF Chemical, 1.6g of antioxidant 168, and 4.8g of light stabilizer 944 produced by Beijing Tiangang Chemical were mixed and melt-blended. The resulting pellets were used to prepare films by a blow molding method to obtain tensile and right-angle tear specimens, which are comparative example 3.

[0065] The obtained comparative example 3 sample was marked as comparative example 4 after artificial ultraviolet accelerated aging.

[0066] Example 1 and Example 2

[0067] 1600g of LLDPE resin 1802 provided by Zhenhai Petrochemical was used as a matrix, and the materials were initially mixed and melt-blended with 0.80g of 1076 and 1.6g of 168 produced by BASF Chemical, 4.8g of 944 produced by Beijing Tiangang Chemical, 1.28g of VP801E produced by Sinopec Beijing Chemical Research Institute, and 3.2g of trimethylolpropane triacrylate (TMPTA) produced by Tianjin Tianjiao Chemical Co., Ltd. The obtained pellets were used to prepare a film by a blow molding method to prepare tensile and right-angle tear specimens, which is Example 1.

[0068] The obtained sample, after artificial ultraviolet accelerated aging, is marked as Example 2.

[0069] Example 3 and Example 4

[0070] 1600g of LLDPE resin 1802 provided by Zhenhai Petrochemical was used as a matrix, and the materials were initially mixed and melt-blended with 0.80g of 1076 produced by BASF Chemical, 1.6g of 168, 4.8g of 944 produced by Beijing Tiangang Chemical, 1.28g of VP801E produced by Sinopec Beijing Chemical Research Institute, and 8g of trimethylolpropane triacrylate (TMPTA) produced by Tianjin Tianjiao Chemical Co., Ltd. The obtained pellets were used to prepare a film by a blow molding method to prepare tensile and right-angle tear specimens, which is Example 3.

[0071] The obtained sample, after artificial ultraviolet accelerated aging, is marked as Example 4.

[0072] Example 5 and Example 6

[0073] 1600g of LLDPE resin 1802 provided by Zhenhai Petrochemical was used as a matrix, and the materials were initially mixed and melt-blended with 0.80g of 1076 produced by BASF Chemical, 1.6g of 168, 4.8g of 944 produced by Beijing Tiangang Chemical, 1.28g of VP801E produced by Sinopec Beijing Chemical Research Institute, and 16g of trimethylolpropane triacrylate (TMPTA) produced by Tianjin Tianjiao Chemical Co., Ltd. The resulting pellets were used to prepare a film by a blow molding method to prepare tensile and right-angle tear specimens, which are Example 5.

[0074] The obtained sample, after artificial ultraviolet accelerated aging, is marked as Example 6.

[0075] Table 1

[0076]

[0077]

[0078] As can be seen from the above table, the transverse tensile load after aging is slightly lower than that before aging, and the transverse tensile loads of several samples are basically the same. For the sample modified with the composite light stabilizer, its longitudinal tensile load after aging is about 2.6 N, which is higher than 1.8 N of the unmodified sample and 2.3 N of the sample modified with 944. The transverse and longitudinal nominal strains of the sample modified with the composite light stabilizer basically do not change after artificial aging. For the sample without light stabilizer, its right-angle tear force value decreases significantly after artificial aging. For the samples modified with light stabilizer and 944, after artificial ultraviolet aging, the longitudinal right-angle tear force value is about 1.2 N, and the transverse right-angle tear force value is about 1.0 N. For the film sample after adding the composite light stabilizer, even after being irradiated with ultraviolet light for 288 h, the transverse right-angle tear basically remains at about 1.0. With the increase of the TMPTA content in the composite light stabilizer, the longitudinal right-angle tear value of the film modified with the composite light stabilizer increases significantly. For the modified film formulation with 1% TMPTA added, its longitudinal right-angle tear force value is 1.305, which is significantly higher than other formulations, and after being aged with artificial violet light for 288 h, this force value also increases by 15%.

[0079] From the above data, in the film system with polyethylene as the main matrix, adding the composite light stabilizer in the present invention is beneficial to simultaneously improve the longitudinal tensile load and longitudinal right-angle tear of the film material under ultraviolet light irradiation. A part of the free radicals generated during the aging process reacts with the ultraviolet crosslinking agent to form a micro-crosslinked structure, which makes the connection between polyethylene molecular chains closer, improving the tensile load and tear strength. This phenomenon is beneficial to maintaining the strength of the film in a high-temperature and high-ultraviolet environment, and is conducive to improving its service life and recovery rate.

[0080] The above examples illustrate the technical effects of the composite light stabilizer in the present invention in the 10-μm mulch film. The composite light stabilizer in the present invention also has excellent performance in thick films (such as cotton packaging films). Examples are shown in the following examples:

[0081] Among the following raw materials, the crosslinked EVA rubber particles produced by the Beijing Research Institute of Chemical Industry have an average particle size of 0.2 microns, and the gel content of the rubber particles is 85 wt%; the nucleating agent HPN20E of MILIKEN.

[0082] Comparative Examples 1B to 5B

[0083] The LLDPE resin 1802 powder provided by Zhenhai Petrochemical was used as the matrix, with a weight of 2000g, and was preliminarily mixed and melt-blended with 0.80g 1076, 1.6g 168, and 8g 944 produced by Beijing Tiangang Chemical. The obtained pellets were blown to prepare films, and tensile and dart impact specimens were prepared as Comparative Example 1B. The obtained specimens were subjected to artificial ultraviolet accelerated aging for 240h, 480h, 720h, and 960h, and were marked as Comparative Example 2B, Comparative Example 3B, Comparative Example 4B, and Comparative Example 5B, respectively.

[0084] The specific process conditions are:

[0085] The process of initial mixing and melt blending of materials is as follows: first weigh all materials according to the proportion, perform preliminary mixing in a high-speed mixer for 20 seconds, and then use a twin-screw extruder for melt blending and granulation. The mixing equipment is a Coperion 35 twin-screw extruder with a speed of 200r / min and a temperature setting of 170°C, 180°C, 190°C, 200°C, 200°C, and 200°C; the obtained pellets are placed in a tray and heated at 70°C o degrees in an oven for 4 hours to remove moisture.

[0086] The film was prepared by blow molding method. The equipment was a German Colin film blowing machine. The temperatures of each section were set at 160°C, 180°C, 200°C, 210°C, 210°C, 210°C, 210°C. The feed amount was 50%, and the winding rate was 2m / min. The obtained film had a smooth surface, an average width of 22cm, and an average thickness of 140μm.

[0087] The prepared tensile and right-angle tearing specimens need to be subjected to artificial ultraviolet aging comparative experiments. The specific conditions of ultraviolet aging are as follows: refer to GB / T16422.3-2014, the light source is a fluorescent ultraviolet lamp, UV-A340 lamp tube, at a wavelength of 340nm, the irradiance is 0.76W / (m 2 ·nm), and UV irradiation was carried out according to the rule of illumination temperature 60℃, radiation time 8h (bright); condensation temperature 50℃, condensation time 4h (dark), and the irradiation time was 240h, 480h, 720h, and 960h.

[0088] The falling dart impact test was carried out according to standard GB / T9639, method B was selected for the experiment, the state adjustment time was 8h, the experimental temperature was 23℃, and the impact damage mass value was obtained.

[0089] The tensile load and nominal strain at break of the specimens were tested in accordance with the national standard GB / T1040.3-2006. The specimens were type 2, 10 mm wide, 50 mm between the initial markings of the fixtures, and 500 mm / min in test speed (no load). The specimens were stretched until they broke, and the maximum tensile load was measured with an accuracy of 0.01 N. The specimens prepared were clearly marked with the specimen number and sampling direction (transverse or longitudinal). The calculation method of the nominal strain at break was the same as above.

[0090] Example 1B to Example 5B

[0091] The LLDPE resin 1802 powder provided by Zhenhai Petrochemical was used as the matrix, with a weight of 2000g, and 0.80g 1076, 1.6g 168, 8g 944 produced by Beijing Tiangang Chemical, 4.8g cross-linked EVA rubber particles produced by Beijing Institute of Chemical Research, 11.2g MILIKEN nucleating agent HPN20E, and 10g trimethylolpropane triacrylate (TMPTA) of Tianjin Tianjiao Chemical Co., Ltd. The materials were initially mixed and melt-blended, and the obtained pellets were used to prepare films by a blow molding method to prepare tensile and dart impact specimens, which were Example 1B. The obtained specimens were marked as Example 2B, Example 3B, Example 4B, and Example 5B respectively after artificial ultraviolet accelerated aging for 240h, 480h, 720h, and 960h.

[0092] The specific process conditions and test methods are the same as those of Comparative Examples 1B to 5B.

[0093] Table 2

[0094]

[0095]

[0096] The data of comparative samples 1-5 show that as the aging time increases, the tensile load, nominal strain at break, and dart impact damage quality of the comparative samples all decrease significantly. For comparative sample 5 with an aging time of 960h, the tensile load is reduced by about 30%, and the dart impact damage quality is reduced by 23%. This is because a large number of free radicals generated during the aging process significantly destroy the long molecular chains in the polyethylene, shortening the polyethylene molecular chains and reducing its tensile load and dart impact damage quality.

[0097] The data of Examples 1-5 show that after the composite light stabilizer is used to modify the polyethylene resin, as the aging time continues to increase, the tensile load loss rate of the example samples remains at a low level, about 10-15%; its nominal strain at break remains basically unchanged, and the loss rate of the dart impact breakage mass also remains at about 10%.

[0098] As can be seen from Table 1, the tensile load and dart impact strength of the comparative film sample without the composite light stabilizer of the present invention before aging are much lower than those of the example samples, indicating that the addition of the composite light stabilizer can improve the mechanical properties of the thick film (140 μm) resin composition.

[0099] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

[0100] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definition in this specification shall prevail.

[0101] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0102] The endpoints and any values ​​of the scope disclosed in the present application document are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, between the endpoint values ​​of each scope, between the endpoint values ​​of each scope and a separate point value, and between separate point values, one or more new numerical ranges can be combined with each other, and these numerical ranges should be considered as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be considered as specifically disclosed in this article.

[0103] In the context of the present specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

[0104] Moreover, any embodiment described in this document may be freely combined with one or more other embodiments described in this document, and the technical solutions or technical ideas formed thereby are deemed to be part of the original disclosure or original record of the present invention, and should not be regarded as new content that has not been disclosed or anticipated in this document, unless a person skilled in the art considers that the combination is obviously unreasonable.

Claims

1. A composite light stabilizer, comprising a light stabilizer, an ultraviolet crosslinking agent, a nucleating agent and rubber particles with a crosslinked structure, wherein, in parts by mass, relative to 1 part of the light stabilizer, the total amount of the nucleating agent and the rubber particles with a crosslinked structure in the composite light stabilizer is 0.2 to 2 parts, and the content of the ultraviolet crosslinking agent is 0.5 to 3.5 parts.

2. The composite light stabilizer according to claim 1, Features: The mass ratio of the rubber particles to the nucleating agent is (3-7): (7-3); and / or, The nucleating agent is selected from at least one of sorbitol derivative nucleating agents, organic carboxylic acid nucleating agents, organic carboxylate nucleating agents, and organic phosphate nucleating agents; more preferably, The nucleating agent is selected from at least one of nucleating agent NA11, nucleating agent NA21, and nucleating agent 20E.

3. The composite light stabilizer according to claim 1, Features: The average particle size of the rubber particles is 0.02 to 2 microns, preferably 0.1 to 1 micron; and / or, The rubber particles are spherical; and / or, The rubber particles have a gel content of 60 wt % or more, preferably 80 wt % or more.

4. The composite light stabilizer according to claim 1, Features: The rubber particles are at least one of the following rubber particles having a cross-linked structure: Natural rubber, styrene-butadiene rubber, carboxylated styrene-butadiene rubber, nitrile rubber, carboxylated nitrile rubber, chloroprene rubber, polybutadiene, acrylic rubber, styrene-butadiene rubber, isoprene rubber, butyl rubber, ethylene-propylene rubber, polysulfide rubber, acrylate-butadiene rubber, polyurethane rubber, fluororubber, ethylene-vinyl acetate rubber.

5. The composite light stabilizer according to claim 1, Features: The rubber particles and the nucleating agent are derived from a resin nucleating agent containing both the rubber particles and the nucleating agent; preferably, the resin nucleating agent is selected from at least one of VP101B, VP101C, and VP801E.

6. The composite light stabilizer according to any one of claims 1 to 5, Features: The ultraviolet crosslinking agent is selected from at least one of the crosslinking agents capable of undergoing isocyanate internal crosslinking and / or ketone hydrazine self-crosslinking reactions; preferably, The ultraviolet crosslinking agent is selected from at least one of trimethylolpropane triacrylate, benzoin, benzoin dimethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, diphenyl acetone, α,α-dimethoxy-α-phenylacetophenone, α,α-diethoxyacetophenone, α-hydroxyalkyl phenone, α-aminoalkyl phenone, aromatic acyl phosphine oxide, bisbenzoylphenyl phosphine oxide, benzophenone, 2,4-dihydroxybenzophenone, thiopropoxythioxanthone, and isopropylthioxanthone.

7. The composite light stabilizer according to any one of claims 1 to 5, Features: The light stabilizer is selected from at least one of the following light stabilizers: Salicylate light stabilizers, benzoate light stabilizers, benzophenone light stabilizers, benzotriazole light stabilizers, triazine light stabilizers, substituted acrylonitrile light stabilizers, oxamide light stabilizers, organic nickel complex light stabilizers, hindered amine light stabilizers; Preferably, the light stabilizer is selected from hindered amine light stabilizers, more preferably at least one selected from light stabilizer 944, light stabilizer 362 and light stabilizer 622.

8. A method for preparing the composite light stabilizer according to any one of claims 1 to 7, comprising the step of mixing raw materials including the light stabilizer, an ultraviolet light crosslinking agent, a nucleating agent and rubber particles having a crosslinking structure.

9. Use of the composite light stabilizer according to any one of claims 1 to 7 or the composite light stabilizer obtained by the preparation method according to claim 8 in a resin composition.

10. A resin composition comprising a base resin, a composite light stabilizer and an optional auxiliary agent; The composite light stabilizer is selected from the composite light stabilizer according to any one of claims 1 to 7 or the composite light stabilizer obtained by the preparation method according to claim 8; preferably, In parts by mass, the content of the composite light stabilizer is 0.3-2 parts relative to 100 parts of the base resin; and / or, The base resin is selected from polyethylene; and / or, The auxiliary agent is selected from antioxidants.

11. A method for preparing the resin composition according to claim 10, comprising melt blending raw materials including a base resin, a composite light stabilizer and optional auxiliary agents to obtain the resin composition.

12. Use of the resin composition according to claim 10 or the resin composition obtained by the preparation method according to claim 11 in agricultural films, polyolefin roofing tiles, and polyolefin rolled plastics.

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