Weather-proof composition resistant to separation and adhesion and preparation method of weather-proof composition

Abstract

The invention relates to the field of high polymer materials, and discloses a weather-proof composition resistant to separation and adhesion and a preparation method thereof.The composition is prepared from, by mass, 10-60 parts of polypropylene powder, 10-40 parts of light stabilizer, 10-40 parts of antioxidant and 5-10 parts of stabilizer, the light stabilizer is UV3853, and the antioxidant is antioxidant SEED. According to the technical scheme, on the premise that the light aging resistance is not sacrificed, the zero-separation viscosity and the high gloss retention rate are achieved at the same time, the core test requirements of the automotive trim PV1306 are comprehensively matched, and the problems that in the industry, a small-molecule light stabilizer is prone to migration and stickiness, and the gloss is greatly lost after light aging are solved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a weather-resistant composition resistant to precipitation and stickiness, and its preparation method. Background Technology

[0002] Polypropylene (PP) is a commonly used material for automotive interior and exterior parts due to its relatively excellent cost performance. The special tertiary carbon structure in the PP molecule results in highly reactive tertiary hydrogen atoms. Under high temperatures and the influence of atmospheric oxygen, moisture, and ultraviolet radiation, polypropylene is prone to molecular chain breakage, leading to decreased mechanical strength, discoloration or fading of products, and even powdering and cracking.

[0003] Currently, the most common way to improve the light stability of polypropylene products is by adding light stabilizers (weather stabilizers) to inhibit molecular chain breakage and delay the performance degradation of polypropylene products. Most automotive OEMs have stringent evaluation standards for the stickiness of interior parts after accelerated photoaging. A representative example is Volkswagen's requirement that interior parts meet the anti-exudation and anti-stickiness requirements specified in the PV1306 standard. The mainstream weather-resistant masterbatch for automotive polypropylene uses a blend of light stabilizers UV3853 and UV2908. However, UV3853 and UV2908 have low melting points and low molecular weights, posing a certain risk of exudation and stickiness. Currently, there is little publicly available literature analyzing the stickiness problem of automotive light stabilizer masterbatches, and even fewer proposing effective countermeasures. After photoaging, the surface gloss of parts usually decreases significantly, and there is also little publicly available literature mentioning how to effectively reduce gloss loss after photoaging.

[0004] Patents CN106750959A and CN112662112A mention overcoming the separation and stickiness of automotive polypropylene, but mainly target scratch-resistant agents and antioxidants. CN109535432A mentions using photo-stabilized silane coupling agents to replace small molecule light stabilizers to avoid the poor compatibility and easy migration caused by the use of conventional small molecule light stabilizers. It solves the problems of blooming and stickiness on the surface of composite materials and the decrease in light stability, and has longer light stability and migration resistance. However, in actual use, photo-stabilized silane coupling agents also have problems such as large addition amount, high price, strong odor and reduced melt index.

[0005] To overcome the shortcomings of the existing technology, developing a weather-resistant composition that is resistant to separation and stickiness, and thus better solves the problem of easy separation and stickiness of light stabilizers, is of great significance in the industry. Summary of the Invention

[0006] The present invention aims to provide a weather-resistant composition and preparation method that is resistant to precipitation and stickiness, so as to solve the problem of easy precipitation and stickiness of light stabilizers in the prior art, and at the same time reduce the gloss reduction of the parts after photoaging.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a weather-resistant composition resistant to precipitation and stickiness, wherein the raw materials, by weight, include 10-60 parts of polypropylene powder, 10-40 parts of light stabilizer, 10-40 parts of antioxidant, and 5-10 parts of stabilizer, wherein the light stabilizer is UV3853 and the antioxidant is antioxidant SEED.

[0008] Preferably, as an improvement, the polyolefin powder is homopolymer polypropylene powder, and the melt index of the polyolefin resin is 2-25 g / 10min.

[0009] Preferably, as an improvement, the stabilizer is β-hydroxyalkylamide.

[0010] Preferably, as an improvement, a method for preparing a weather-resistant composition resistant to precipitation and stickiness includes the following steps: S1. First, mix the homopolymer polypropylene powder and the light stabilizer UV3853 together in an intensive kneading process. S2. The internally mixed mixture is fed into a twin-screw extruder for melt extrusion granulation, and then water-cooled and pelletized after extrusion. S3. After mixing the above extruded products, antioxidant SEED, and stabilizer evenly in proportion, the mixture is then melt-extruded and granulated using a twin-screw extruder. After extrusion, the mixture is water-cooled and pelletized to obtain weather-resistant masterbatch.

[0011] Preferably, as an improvement, in step S1, the mixing temperature is 180-230℃ and the mixing time is 30-60min.

[0012] Preferably, as an improvement, in step S2, the temperatures of each extrusion section are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, and die head temperature 190-200℃.

[0013] Preferably, as an improvement, in step S3, the temperatures of each extrusion section are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, and die head temperature 190-200℃.

[0014] The principle and advantages of this solution are as follows: In practical applications, the mainstream approach for automotive weather-resistant masterbatches currently involves compounding light stabilizers UV3853 and UV2908. However, due to the small molecular weight and low melting point of UV3853 and UV2908, there is a risk of precipitation and sticking. Furthermore, traditional automotive weather-resistant agents also suffer from a significant decrease in gloss after photoaging of manufactured parts. During the research and development process, the inventors discovered that compounding the antioxidant SEED, which contains a piperidine group structure, with UV3853 also exhibits considerable resistance to photoaging. The antioxidant SEED can inhibit polymer oxidative aging and absorb or shield ultraviolet rays. Its melting point is much higher than the sticking test temperature mentioned in the weathering standards of various OEMs, therefore its resistance to sticking is far superior to UV2908.

[0015] Through a series of scientific formulation designs and extensive experimental research, the inventors discovered that hindered amine light stabilizers, supplemented with highly reactive β-hydroxyalkylamides, can significantly reduce the gloss reduction of parts after photoaging. β-hydroxyalkylamides possess high low-temperature reactivity, reacting with the polar groups on the surface of talc without a catalyst, thus preventing the adsorption of light stabilizers by talc and promoting the compatibility between light stabilizers and resins. This effectively enhances the light stabilizer's UV absorption efficiency and blocks the photoaging chain reaction.

[0016] To further improve the compatibility of light stabilizer UV3853 with polypropylene, extensive experiments have determined that: homopolymer polypropylene powder without antioxidants is co-mixed and extruded with UV3853. The free radicals generated by the homopolymer polypropylene powder under high temperature and high shear conditions undergo a grafting reaction with UV3853, which has an unsaturated double bond structure. This effectively solves the problem of UV3853 precipitation and stickiness. In the preparation of the weather-resistant masterbatch, to ensure the effective grafting reaction, the process needs to be carried out in steps: the first step involves adding only homopolymer polypropylene powder without antioxidants and UV3853, as antioxidants inhibit the generation of polypropylene free radicals, thus affecting the grafting rate. Simultaneously, this method does not use peroxides to initiate polypropylene free radicals because peroxides have a strong odor, and their residue may lead to defects such as gas marks in the molded parts later.

[0017] During the technology research and development stage, the inventors tried adding epoxy resin to introduce highly active epoxy groups, but this did not significantly improve the gloss of the parts after photoaging.

[0018] In summary, the beneficial effects of this technical solution are as follows: 1. This technical solution completely solves the problem of tackiness after photoaging and achieves the optimal tack resistance level: After photoaging, the tackiness of Examples 1-4 is all Grade 1 (non-sticky), which fully meets the stringent standards of automotive interiors.

[0019] 2. This technical solution significantly improves the gloss retention rate after photoaging and significantly reduces gloss loss: Examples 1-4: gloss retention rate is 93%~95% after 2000h and remains stable at 89%~95% after 3000h.

[0020] 3. This technical solution maintains excellent resistance to light aging, with minimal color difference after light aging: Examples 1-4: 2000h color difference ΔE 0.37~0.43, 3000h ΔE 0.74~0.82, the color difference change is negligible. Detailed Implementation

[0021] The following detailed description provides further details on specific embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; and the materials and reagents used are all commercially available.

[0022] Overview of the plan: A weather-resistant composition resistant to precipitation and stickiness, comprising, by weight, 10-60 parts polypropylene powder, 10-40 parts light stabilizer, 10-40 parts antioxidant, and 5-10 parts stabilizer.

[0023] The polyolefin powder is homopolymer polypropylene powder, and the melt index of the polyolefin resin is 2-25 g / 10 min. The test conditions are 2.16 kg × 230 ℃.

[0024] The light stabilizer is UV3853.

[0025] The antioxidant is antioxidant SEED.

[0026] The stabilizer is β-hydroxyalkylamide.

[0027] A method for preparing a weather-resistant composition resistant to precipitation and stickiness includes the following steps: S1. First, mix the homopolymer polypropylene powder and light stabilizer UV3853 together in an intensive mixing chamber at a temperature of 180-230℃ for 30-60 minutes.

[0028] S2. The internally mixed mixture is fed into a twin-screw extruder for melt extrusion granulation. The extrusion temperatures are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, die temperature 190-200℃. After extrusion, the mixture is water-cooled and pelletized.

[0029] S3. After mixing the above extruded products, antioxidant SEED, and stabilizer evenly in proportion, the mixture is then melt-extruded and granulated using a twin-screw extruder. The extrusion temperatures are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, and die temperature 190-200℃. After extrusion, the mixture is water-cooled and pelletized to obtain weather-resistant masterbatch.

[0030] Example 1 A weather-resistant composition resistant to precipitation and stickiness, comprising, by weight, 10-60 parts polypropylene powder, 10-40 parts light stabilizer, 10-40 parts antioxidant, and 5-10 parts stabilizer.

[0031] Among them, the polyolefin powder is homopolymer polypropylene powder with a melt index of 15g / 10min and test conditions of 2.16kg×230℃.

[0032] The light stabilizer is UV3853.

[0033] The antioxidant is antioxidant SEED.

[0034] The stabilizer is β-hydroxyalkylamide.

[0035] A method for preparing a weather-resistant composition resistant to precipitation and stickiness includes the following steps: S1. First, mix the homopolymer polypropylene powder and light stabilizer UV3853 together in an intensive mixing chamber at a temperature of 180℃ for 30 minutes.

[0036] S2. The internally mixed mixture is fed into a twin-screw extruder for melt extrusion granulation. The extrusion temperatures are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, die temperature 190-200℃. After extrusion, the mixture is water-cooled and pelletized.

[0037] S3. After mixing the above extruded products, antioxidants and stabilizers evenly in proportion, the mixture is then melt-extruded and granulated using a twin-screw extruder. The extrusion temperatures are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, and die temperature 190-200℃. After extrusion, the mixture is water-cooled and pelletized to obtain weather-resistant masterbatch.

[0038] Examples 2-4 are embodiments of the present invention, and Comparative Examples 1-5 are comparative examples of the present invention. The difference between each embodiment and comparative example and Example 1 lies in the amount of each component added (by mass), as detailed in the table below. The preparation methods of each embodiment and comparative example are the same as those in the general description of the above scheme, except for the specific selection of raw materials, to obtain the weather-resistant masterbatches of Examples 1-4 and Comparative Examples 1-5.

[0039] Table 1 Material Name Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Homopolymer polypropylene powder 45 45 42 40 50 50 45 50 - Copolymer polypropylene - - - - - - - - 45 Light stabilizer UV3853 25 30 25 25 25 25 25 30 25 Antioxidant SEED 25 20 25 25 25 - - 20 25 Light stabilizer UV2908 - - - - - 25 25 - - β-hydroxyalkylamide 5 5 8 10 - - 5 - 5 Comparative Example 6 The difference between this comparative example and Example 1 is that the homopolymer polypropylene powder and light stabilizer UV3853 were not separately pulverized in advance, but were directly extruded together with antioxidants and stabilizers in the preparation method of this comparative example.

[0040] Comparative Example 7 The difference between this comparative example and Example 1 is that the antioxidant in this comparative example is antioxidant 1790.

[0041] Comparative Example 8 The difference between this comparative example and Example 1 is that the stabilizer in this comparative example is epoxy resin HY909.

[0042] Comparative Example 9 The difference between this comparative example and Example 1 is that the amount of antioxidant SEED and UV3853 added in this comparative example is 5 parts and 45 parts, respectively.

[0043] Application examples 63 parts of polypropylene, 8 parts of POE elastomer, 8 parts of HDPE, 20 parts of talc, 1 part of light yellow masterbatch, 0.4 parts of antioxidant, and 0.35 parts of weather-resistant masterbatch prepared in the above examples and comparative examples were mixed evenly and then melt-extruded and cooled in an extruder at 150-200℃.

[0044] Meanwhile, the deodorizing compositions prepared without the addition of the comparative and examples were used as blank control groups.

[0045] The modified particles for automotive interior trim prepared in the above application examples and blank control group were dried in a drying oven at 80℃ for 2 hours. The dried particles were then injection molded into glossy color swatches at an injection molding temperature of 220℃-230℃. The test methods and results are as follows: 1. Long-term photoaging test Xenon lamp aging test conditions: 0.55W / m 2 @340nm, 60min under darkness with spray, blackboard temperature 38℃, relative humidity 95%; 40min under light (no spray), blackboard temperature 70℃, relative humidity 50%; 20min under light with spray, blackboard temperature 70℃; 60min under light (no spray), blackboard temperature 70℃, relative humidity 50%.

[0046] Every 1000 hours of testing, observe the separation and stickiness of the color sample, and compare the color difference and gloss of the color sample before and after aging.

[0047] 2. Color difference test The color difference change of the samples before and after light aging was tested using the Japanese Minol CM-3600A color testing system, and the ΔE value of the material was recorded.

[0048] 3. Gloss test Gloss was tested at a light field angle of 60° according to the method specified in ASTM D523.

[0049] 4. Sedimentation and viscosity test The tackiness performance of the product is in accordance with Volkswagen PV1306.

[0050] Each group underwent three repeated tests, and the results are shown in Table 2: Table 2

[0051] Based on the test results of Examples 1-4 above, the weather-resistant composition of the present invention can effectively improve the color difference and gloss variation range of automotive interior parts under photoaging, and effectively solve the problem of precipitation and stickiness.

[0052] By combining Implementation 1, Comparative Examples 2 and 3, it can be found that when the antioxidant SEED is used to replace UV2908, the color difference value of the color sample after photoaging is basically the same, and the photoaging resistance is also the same. However, the use of the high melting point antioxidant SEED can overcome the precipitation and stickiness phenomenon.

[0053] Based on Examples 1, 2, 3, 1 (Comparative), and 4 (Comparative), it can be observed that the stabilizer β-hydroxyalkylamide can effectively improve the gloss retention rate after photoaging, achieving a gloss retention rate of >85%. Increasing the amount of β-hydroxyalkylamide further enhances the gloss retention rate and improves the polymer's resistance to photoaging.

[0054] By comparing Example 1, Comparative Example 5, and Comparative Example 6, it can be found that the copolymer polypropylene, due to the presence of antioxidants, cannot generate enough free radicals to graft with UV3853 during the mixing and extrusion processes, thus failing to effectively improve the precipitation and stickiness phenomenon. In Comparative Example 6, because the homopolymer polypropylene powder and antioxidants were mixed together, the presence of the antioxidants affected the generation of polypropylene free radicals, therefore the polypropylene could not undergo a grafting reaction with UV3853, resulting in a more severe stickiness phenomenon after the final formulation system aged.

[0055] Comparative Example 7 uses high-temperature resistant antioxidant 1790 instead of UV2908. Although antioxidant 1790 has a high melting point and good long-term high-temperature aging resistance, it lacks the light aging resistance of UV-2908, resulting in a significant increase in color difference and a decrease in gloss after light aging.

[0056] Comparative Example 8 attempted to use epoxy resin instead of hydroxyalkylamide to passivate talc. Although it reduced the adsorption of light stabilizer by talc, its reactivity was insufficient and its compatibility was poor. The gloss still decreased significantly after aging.

[0057] In the formulation of Comparative Example 9, the light stabilizer component is mainly UV3853, with only a small amount of antioxidant SEED added. Although it has little effect on the color difference due to photoaging, the high UV3853 content makes it difficult to ensure that UV3853 and the polypropylene matrix can fully bond due to the lubricity of UV3853 itself and the limited free radicals produced by polypropylene during the mixing and extrusion process. Therefore, it cannot completely improve the stickiness phenomenon after the system ages.

[0058] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A weather-resistant composition resistant to precipitation and stickiness, characterized in that: The raw materials, by weight, include 10-60 parts of polypropylene powder, 10-40 parts of light stabilizer, 10-40 parts of antioxidant, and 5-10 parts of stabilizer. The light stabilizer is UV3853, and the antioxidant is antioxidant SEED.

2. The weather-resistant composition resistant to precipitation and stickiness according to claim 1, characterized in that: The polyolefin powder is homopolymer polypropylene powder, and the melt index of the polyolefin resin is 2-25 g / 10min.

3. The weather-resistant composition resistant to precipitation and stickiness according to claim 2, characterized in that: The stabilizer is a β-hydroxyalkylamide.

4. A method for preparing a weather-resistant composition resistant to precipitation and stickiness according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. First, mix the homopolymer polypropylene powder and the light stabilizer UV3853 together in an intensive kneading process. S2. The intensively mixed mixture is fed into a twin-screw extruder for melt extrusion granulation, and then water-cooled and pelletized after extrusion. S3. After mixing the above extruded products, antioxidant SEED, and stabilizer evenly in proportion, the mixture is then melt-extruded and granulated using a twin-screw extruder. After extrusion, the mixture is water-cooled and pelletized to obtain weather-resistant masterbatch.

5. The method for preparing a weather-resistant composition resistant to precipitation and stickiness according to claim 4, characterized in that: In step S1, the mixing temperature is 180-230℃ and the mixing time is 30-60 minutes.

6. The method for preparing a weather-resistant composition resistant to precipitation and stickiness according to claim 5, characterized in that: In step S2, the temperatures of each extrusion section are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, and die head temperature 190-200℃.

7. A method for preparing a weather-resistant composition resistant to precipitation and stickiness according to claim 6, characterized in that: In step S3, the temperatures of each extrusion section are as follows: feeding section 130-160℃, melting section 160-180℃, conveying section 180-200℃, and die head temperature 190-200℃.

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