Polymer ultraviolet-proof rainproof cloth and preparation method thereof

Abstract

The application discloses a high-molecular anti-UV rainproof cloth and a preparation method thereof, and belongs to the technical field of high-molecular materials. The high-molecular anti-UV rainproof cloth is made of raw materials containing the following components in parts by mass: 100 parts of high-density polyethylene, 20-35 parts of polypropylene, 10-20 parts of polyisobutene, 10-18 parts of alpha-olefin ethylene copolymer, 1.5-3.5 parts of a benzotriazole light absorber, and 0.5-1.0 parts of a processing aid. By adding the benzotriazole light absorber with a specific structure, the absorber absorbs ultraviolet rays with a wavelength of 280-400 nm, converts light energy into heat energy and releases the heat energy, and blocks photo-oxidation reactions caused by the ultraviolet rays, so that problems such as material embrittlement, mechanical property reduction, early discoloration, surface cracking and water-proof function failure of the rainproof cloth are effectively prevented, and the service life of the rainproof cloth is significantly prolonged.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and particularly relates to a high polymer rainproof cloth with ultraviolet resistance and a preparation method thereof. BACKGROUND

[0002] Rainproof cloth is widely used in outdoor activities, industry, agriculture, construction and other fields. Whether it is used to cover goods, build temporary shelters, or as a waterproof material for the exterior of buildings, rainproof cloth plays an indispensable role. However, there are some problems in the actual use of most rainproof cloths on the market that need to be solved urgently.

[0003] Traditional rainproof cloth is mostly made of polyvinyl chloride (PVC), polyester fiber, polypropylene and other materials. These materials perform well in waterproof performance, but when exposed to long-term ultraviolet radiation, they often show signs of material aging, brittleness, discoloration, etc. For example, after being used outdoors for several months, the molecular chain of polyester fiber rainproof cloth gradually breaks due to the photochemical effect of ultraviolet light, resulting in a decrease in cloth strength and the appearance of cracks and holes, which not only affects the service life, but also may cause significant losses due to the failure of protective performance.

[0004] In addition, the processing technology of traditional rainproof cloth also has limitations. In the production process, in order to achieve certain waterproof and strength performance, a large amount of plasticizer, stabilizer and other chemical additives are usually added. These additives may gradually migrate to the surface of the material under high temperature, light and other conditions, not only polluting the environment, but also potentially harming human health. Moreover, the production process of traditional rainproof cloth is complex, the production cycle is long, and the energy consumption is large, which makes it difficult to meet the requirements of modern industry for efficient and environmentally friendly production.

[0005] In practical applications, the dimensional stability of traditional rainproof cloth is also poor. In an environment with large changes in temperature and humidity, the material is prone to shrinkage and deformation, which reduces the sealing performance between the rainproof cloth and the covered object, increasing the risk of rainwater penetration. Especially in some large outdoor storage scenarios, once the large-area rainproof cloth deforms, it will take a lot of manpower and material resources to adjust and fix it.

[0006] Therefore, it is of great significance to develop a new type of rainproof cloth with excellent ultraviolet resistance, environmental protection, dimensional stability and simple processing technology, which can improve the service life and application effect of rainproof cloth. It is also one of the technical problems to be solved in the field of high polymer materials. SUMMARY

[0007] The present application aims at solving the problems of the existing rainproof cloth, such as easy to be aged by ultraviolet, easy to be aged and brittle, discoloration and the like, and provides a novel rainproof cloth absorbing ultraviolet and a preparation method thereof.

[0008] To achieve the above object, the technical scheme adopted by the present application is as follows: a rainproof cloth absorbing ultraviolet, which is made of raw materials containing the following components by mass: high-density polyethylene 100 parts, polypropylene 20-35 parts, polyisobutylene 10-20 parts, alpha-olefin ethylene copolymer 10-18 parts, benzotriazole light absorber 1.5-3.5 parts, and processing aid 0.5-1.0 parts.

[0009] The benzotriazole light absorber is a compound shown in the following formula 1:

[0010]

[0011] The R1 is selected from the group consisting of methyl, ethyl, tert-butyl and phenyl.

[0012] Further, the density of the high-density polyethylene is 0.94-0.96 g / cm 3 .

[0013] Further, the benzotriazole light absorber is any one of the compounds shown in the following structures:

[0014]

[0015] Further, the processing aid is calcium stearate.

[0016] A preparation method of the rainproof cloth absorbing ultraviolet, comprising the following steps:

[0017] S1. mixing high-density polyethylene, polypropylene, polyisobutylene, alpha-olefin ethylene copolymer, benzotriazole light absorber and processing aid according to the mass ratio to obtain a mixture;

[0018] S2. adding the mixture into a double-screw extruder to extrude into a film in a molten state;

[0019] S3. calendering the film into a rainproof cloth with a desired thickness through a calender, and cooling, cutting the calendered rainproof cloth to obtain a rainproof cloth absorbing ultraviolet.

[0020] Further, the temperature of the melting in S2 is 180-220 DEG C, and the screw rotation speed is 50-100 rpm.

[0021] Further, the pressure of the S3 is 10-20 MPa, and the temperature of the calender roller is 80-100 DEG C.

[0022] Further, the cooling treatment in the S3 includes air cooling using a cooling roller, the cooling time is 10-30 seconds, and the cooling temperature is controlled at 20-30 DEG C.

[0023] Further, the cutting in the S3 is performed using an automatic cutting machine, the size of the sheet is 2m*2m to 4m*6m, and the edges of the sheet are trimmed after cutting.

[0024] The application of the high-molecular anti-UV rainproof cloth in plastic rainproof cloth for plastic vegetable greenhouse and rainproof cloth for airing.

[0025] The benzotriazole light absorber has a specific conjugated structure, and the benzotriazole ring in the molecule can efficiently absorb ultraviolet rays with a wavelength range of 280-400 nm. When the ultraviolet rays irradiate the surface of the rainproof cloth, the benzotriazole light absorber absorbs photon energy through electronic transition and converts it into harmless heat energy, rather than damaging the polymer chain. The R1 group is a hydrophobic group that enhances the stability of the molecule and reduces the migration and precipitation of the benzotriazole light absorber in the material, ensuring long-term effectiveness. The nitrogen atom on the triazole ring can form a weak hydrogen bond with the adjacent polymer chain, so that the benzotriazole light absorber is uniformly dispersed in the base material, improving the ultraviolet absorption efficiency. By blocking the photo-oxidation reaction induced by ultraviolet rays, the benzotriazole light absorber can significantly delay the molecular chain rupture of the main material such as high-density polyethylene and polypropylene, thereby preventing the rainproof cloth from appearing material embrittlement and mechanical property decline, early discoloration, surface cracking and water-proof function failure.

[0026] The application comprehensively improves the anti-UV, anti-aging and anti-fading performance of the rainproof cloth through a multi-component synergistic mechanism. In the core component, the benzotriazole light absorber efficiently absorbs 280-400 nm ultraviolet light through a specific conjugated structure, converts the light energy into heat energy, and releases it, thereby blocking the ultraviolet-induced high molecular chain rupture; the R1 hydrophobic group reduces migration, and the nitrogen atom in the triazole ring forms a weak hydrogen bond with the high molecular chain, thereby improving the dispersion stability. The synergistic enhancement of the base resin: high-density polyethylene provides a rigid skeleton and a waterproof barrier, and the high-density structure shortens the penetration path of ultraviolet light; polypropylene strengthens the mechanical strength, polyisobutylene improves the low-temperature toughness, and alpha-olefin ethylene copolymer acts as a compatibilizer to promote the uniform dispersion of benzotriazole and eliminate agglomeration failure. The calcium stearate processing aid reduces the friction heat of the melt and prevents the decomposition of the light absorber during high-temperature processing. The preparation process further strengthens the synergistic effect: double-screw extrusion (180-220℃, 50-100rpm) precisely controls the temperature to avoid resin degradation, and the screw shear force ensures the high dispersion of the components; calendering (10-20MPa, 80-100℃) high pressure makes the molecular chains closely arranged, reduces internal defects, and reduces the weak points of ultraviolet erosion; gradient cooling (air cooling 20-30℃, 10-30 seconds) quickly sets the shape, inhibits excessive crystallinity, maintains the ductility of the material, and avoids embrittlement. In summary, each component realizes systematic protection through molecular design, physical property complementation and process control, and comprehensively solves the problems of degradation, embrittlement and fading caused by ultraviolet light. The benzotriazole light absorber in the high-molecular anti-UV rainproof cloth described in the application absorbs part of the ultraviolet light, and the remaining ultraviolet light can pass through the rainproof cloth to provide the necessary light source for plant photosynthesis.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] 1. The anti-UV performance is significantly improved: by adding a benzotriazole light absorber with a specific structure, the absorber can efficiently absorb 280-400 nm ultraviolet light and convert the light energy into heat energy, thereby blocking the photooxidation reaction induced by ultraviolet light, effectively preventing the rainproof cloth from appearing material embrittlement, mechanical property degradation, early fading, surface cracking and waterproof function failure, and significantly prolonging the service life of the rainproof cloth.

[0029] 2. Environmental protection is enhanced: in the production process, the amount of chemical additives such as plasticizers and stabilizers required by traditional rainproof cloth is reduced, thereby reducing the risk of environmental pollution and potential harm to human health caused by the migration of these additives to the surface of the material under high temperature and light conditions, and better meeting the requirements of modern industry for environmentally friendly production.

[0030] 3. Improved dimensional stability: The processing technology is optimized, and the temperature and pressure are precisely controlled through double-screw extrusion, calendering, gradient cooling, and other processes, so that the molecular chains are closely arranged, internal defects are reduced, and excessive crystallinity is inhibited, thereby maintaining the ductility of the material, avoiding embrittlement, enhancing the dimensional stability of the rainproof cloth in environments with large temperature and humidity changes, reducing the risk of rainwater penetration, and reducing the human and material resources consumed for later adjustment and fixation. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 For the benzotriazole-based light absorber described in the present application 1 HNMR chart. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0033] Synthesis Example 1

[0034] Synthesis of benzotriazole-based light absorber 1:

[0035]

[0036] First step: under a nitrogen atmosphere, 20.00 g of raw material 1, 12.82 g of raw material 2, 0.55 g of tri-tert-butyl phosphine, 0.32 g of palladium on carbon, 14.97 g of anhydrous potassium carbonate, and 250 g of toluene were added to the reaction system, and the temperature was raised to 120°C to reflux for 12 hours; after the reaction was completed, the temperature was slightly lowered, diatomaceous earth was used for filtration, the filtrate was cooled to room temperature, and then washed with water three times, the organic phase was retained, then the aqueous phase was extracted with ethyl acetate, the organic phases were combined, the organic phase was dried with anhydrous magnesium sulfate, filtered, and rotary evaporated, and then silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate as the eluent, and then rotary evaporated to obtain 21.15 g of intermediate 1.

[0037] Second step: under nitrogen atmosphere, 21.15 g of intermediate 1, 11.66 g of raw material 3, 23.20 g of potassium phosphate trihydrate, 0.05 g of pyridine-2-carboxylic acid, 0.4 g of CuI and 300 g of DMSO were added into the reaction system, heated to 85℃ for 16 h; after cooling, the obtained reaction mixture was extracted with ammonia solution and methyl tert-butyl ether, the organic phase was washed with water five times, and then washed with saturated NaCl solution twice; finally, the combined organic phase was dried with anhydrous Na2SO4, rotary evaporation, and purified by silica gel column with a mixture of petroleum ether and ethyl acetate as eluent, and the solution was rotary evaporated to obtain 21.49 g of benzotriazole light absorber 1.

[0038] Structure identification:

[0039] MS (m / z) of intermediate 1: [M+H] + = 486;

[0040] MS (m / z) of benzotriazole light absorber 1: [M+H] + = 628;

[0041] HNMR of benzotriazole light absorber 1: 1 Chloroform-d: δ 7.95-7.77 (m, 4H), 7.69-7.37 (m, 8H), 7.24 (s, 1H), 7.04 (dd, 1H), 4.03 (s, 2H), 2.49 (s, 3H), 1.07-0.96 (m, 9H).

[0042] Synthesis examples 2-4

[0043] Benzotriazole light absorbers 2-4 were synthesized in synthesis examples 2-4 in turn, referring to the synthesis method of synthesis example 1, replacing raw material 2 therein, and the rest was the same as synthesis example 1. The structures of raw material 2, benzotriazole light absorbers 2-4, MS (m / z): [M+H] + The data are shown in Table 1.

[0044] Table 1. The structures of raw material 2, benzotriazole light absorbers 2-4, MS (m / z): [M+H] involved in synthesis examples 2-4 + data.

[0045]

[0046]

[0047] Example 1

[0048] Preparation of a high-molecular anti-UV rain cloth:

[0049] 1. Raw material mass ratio: high-density polyethylene 100 parts, polypropylene 27.5 parts, polyisobutylene 15 parts, alpha-olefin ethylene copolymer 14 parts, benzotriazole light absorber 2.5 parts, processing aid 0.75 parts;

[0050] The density of the high-density polyethylene is 0.95 g / cm 3 ;

[0051] The benzotriazole light absorber is the benzotriazole light absorber 1 synthesized in Synthesis Example 1;

[0052] The processing aid is calcium stearate.

[0053] 2. Preparation method:

[0054] S1. The high-density polyethylene, polypropylene, polyisobutylene, alpha-olefin ethylene copolymer, benzotriazole light absorber 1, and calcium stearate are added to a high-speed mixer in the above mass ratio, mixed at a speed of 500 rpm for 15 minutes at room temperature to ensure uniform dispersion of each component, and a mixture is obtained;

[0055] S2. The mixture is added to a twin-screw extruder and extruded into a film in a molten state. The melting temperature is 200°C, and the screw speed is set to 75 rpm;

[0056] S3. The extruded film is sent to a calender machine to be calendered into a rainproof cloth blank with a thickness of 0.5 mm under a pressure of 15 MPa and a calender roll temperature of 90°C. Subsequently, the calendered rainproof cloth is subjected to cooling treatment: air cooling using a cooling roll, cooling time 20 seconds, cooling temperature controlled at 25°C. After cooling, the rainproof cloth is cut into a sheet with a size of 3m x 4m using an automatic cutting machine, and a high-molecular ultraviolet-resistant rainproof cloth is obtained.

[0057] Examples 2-4

[0058] A high-molecular ultraviolet-resistant rainproof cloth is prepared according to the preparation method of Example 1, wherein the benzotriazole light absorber is replaced by the benzotriazole light absorbers 2-4 synthesized in Synthesis Examples 2-4, respectively, and the rest remains the same as in Example 1.

[0059] Comparative Example 1

[0060] A high-molecular ultraviolet-resistant rainproof cloth is prepared according to the preparation method of Example 1, wherein the benzotriazole light absorber is replaced by Comparative Compound 1, and the rest remains the same as in Example 1.

[0061] Comparative Compound 1:

[0062] Comparative Example 2

[0063] A high molecular anti-UV rain cloth was prepared according to the preparation method of Example 1, without adding the benzotriazole light absorber therein, and the rest was the same as Example 1.

[0064] Comparative Example 3

[0065] A high molecular anti-UV rain cloth was prepared according to the preparation method of Example 1, replacing the benzotriazole light absorber therein with 2360, CAS No. 103597-45-1, and the structure is as follows:

[0066] Comparative Example 4

[0067] A high molecular anti-UV rain cloth was prepared according to the preparation method of Example 1, replacing the mass fraction of polypropylene therein with 10 parts, and the rest was the same as Example 1.

[0068] Comparative Example 5

[0069] A high molecular anti-UV rain cloth was prepared according to the preparation method of Example 1, replacing the mass fraction of polyisobutylene therein with 30 parts, and the rest was the same as Example 1.

[0070] Performance test:

[0071] 1. The tensile strength of a high molecular anti-UV rain cloth prepared in the examples and comparative examples was tested according to GB / T 1040-92, and the data is shown in Table 2.

[0072] 2. The light aging performance (fluorescent ultraviolet lamp exposure test) of a high molecular anti-UV rain cloth prepared in the examples and comparative examples was tested according to GB / T 14522-1993, the light source was UV-A lamp, the ultraviolet wavelength was 351 nm, and the data is shown in Table 2.

[0073] Table 2. Performance test data of a high molecular anti-UV rain cloth prepared in the examples and comparative examples.

[0074]

[0075]

[0076] The rainproof cloth added with the benzotriazole light absorber of the application shows significantly superior aging resistance, the anti-ultraviolet ability is obviously improved, and the mechanical stability of the material after ultraviolet aging is maintained well; in contrast, the groups without adding the light absorber or using other light absorbers show that the anti-aging performance deteriorates sharply, indicating that the presence of the benzotriazole light absorber of the application is crucial for blocking ultraviolet degradation. The balance of components in the polymer formula also dominates the performance trend - insufficient polypropylene or excessive polyisobutylene will lead to simultaneous decrease of initial strength and aging resistance, highlighting the decisive influence of raw material ratio optimization on overall durability.

[0077] Although embodiments of the application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the application, the scope of the application being defined by the appended claims and their equivalents.

Claims

1. A high molecular ultraviolet protection rainproof cloth, characterized in that, The raw materials include the following components by mass: high-density polyethylene 100 parts, polypropylene 20-35 parts, polyisobutylene 10-20 parts, alpha-olefin ethylene copolymer 10-18 parts, benzotriazole light absorber 1.5-3.5 parts, and processing aid 0.5-1.0 parts; The benzotriazole light absorber is a compound shown in the following structure: The R1 is selected from the group consisting of methyl, ethyl, tert-butyl, and phenyl.

2. The rainproof cloth according to claim 1, wherein the rainproof cloth is a rainproof cloth for preventing ultraviolet rays. The high density polyethylene has a density of 0.94 to 0.96 g / cm 3 .

3. The rainproof cloth with high molecular anti-UV according to claim 1, characterized in that, The benzotriazole light absorber is any one of the compounds shown in the following structures:

4. The rainproof cloth with high molecular anti-UV according to claim 1, characterized in that, The processing aid is calcium stearate.

5. The method for preparing the high-molecular anti-UV and rainproof cloth according to any one of claims 1-4, characterized in that, The method comprises the following steps: S1. Mixing high-density polyethylene, polypropylene, polyisobutylene, alpha-olefin ethylene copolymer, benzotriazole light absorber, and processing aid in a mass ratio to obtain a mixture; S2. Adding the mixture into a double-screw extruder to extrude into a film in a molten state; S3. Calendering the film into a rainproof cloth of a desired thickness by using a calender, and performing cooling treatment on the calendered rainproof cloth, cutting to obtain a high-molecular ultraviolet-proof rainproof cloth.

6. The method of claim 5, wherein the polymer-based rainproof fabric is prepared by the steps of: (a) preparing a solution of a polymer-based UV blocking agent; (b) applying the solution of the polymer-based UV blocking agent to a surface of a rainproof fabric; and (c) drying the rainproof fabric. The temperature of melting in S2 is 180-220℃, and the screw rotation speed is 50-100 rpm.

7. The method of claim 5, wherein the method further comprises the step of: The calendering pressure in S3 is 10-20 MPa, and the calender roll temperature is 80-100℃. ​ 8. The method of claim 5, wherein the method further comprises the step of: coating the polymer with a water repellent agent. The cooling treatment in S3 comprises air cooling by using a cooling roll, the cooling time is 10-30 seconds, and the cooling temperature is controlled at 20-30℃.

9. The method for preparing a polymeric ultraviolet-resistant rainproof fabric according to claim 5, characterized in that, The cutting in S3 is performed by using an automatic cutting machine, the sheet size is 2m×2m to 4m×6m, and the edges of the sheet are trimmed after cutting.

10. Application of the high-molecular ultraviolet-proof rainproof cloth in any one of claims 1-4 to rainproof plastic for plastic vegetable greenhouse and rainproof plastic for sunning.

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