A high-performance low-condensation atomized modified polypropylene and preparation method thereof

Abstract

The invention discloses a high-performance low-condensation atomization modified polypropylene and a preparation method thereof, comprising the following components and mass percentages: 50-80% polypropylene, 1-15% toughening agent, 0-10% polyethylene, 5-20% talcum powder, 1-10% functional filler, 0.2-1% lubricant, 0.1-0.5% antioxidant, and 0.2-1% adsorbent. The invention can effectively maintain or even greatly improve the mechanical properties, heat resistance and dimensional stability of the material while reducing the amount of talcum powder by adding special functional fillers in the formula. At the same time, through the optimized combination of functional fillers and adsorbents, lubricants, antioxidants and polyethylene, the precipitation of small molecular substances in the production and use process of the material in a high-temperature environment can be effectively reduced, so that the gloss retention rate of the parts prepared by the SAEJ 1756 gloss method when testing condensation atomization can exceed 90%.

Description

Technical Field

[0001] The invention relates to high-performance low-condensation atomized modified polypropylene and a preparation method thereof. Background Art

[0002] In the field of automobile manufacturing, modified plastics can be widely used in systems such as engine compartments, bumpers, dashboards, pillars, door panels, and sunroofs. Among them, modified polypropylene (PP) is a typical representative. Due to its excellent cost-effectiveness, mechanical properties, chemical resistance and processability, it is widely used in the preparation of automotive interior and exterior parts.

[0003] In recent years, with the development of the automotive industry, demands for modified automotive plastics have become increasingly stringent, including color diversity, enhanced mechanical properties, and optimized emission performance. Improved mechanical properties can meet the diverse demands of parts, such as lightweighting and thinning. Optimized emission performance, on the other hand, aims to provide a better driving experience for consumers, such as enhancing odor to enhance mood. Condensation fogging, on the other hand, is caused by the presence of volatile substances in automotive interior materials (such as surface leather, interior textiles, and structural plastics). These substances condense on cool window surfaces, impairing the driver's vision and potentially posing a safety hazard.

[0004] There are basically two methods for characterizing condensation fogging. The first is the weight method. Under certain test conditions, the gas of the sample after being heated in the fogging cup condenses on the low-temperature aluminum foil. The weight of the sample fogged condensate is calculated by weighing the weight change of the aluminum foil before and after. The second is the glossiness method. Under certain test conditions, small molecules begin to volatilize after the sample is heated, and the volatile gas condenses on the glass plate that has been cooled by the cooling chamber. The glossiness value of the glass plate before and after condensation is compared and calculated, and the appearance of the glass plate is evaluated at the same time. At present, the evaluation method adopted by most automobile manufacturers is the gram weight method. However, because the gram weight method mainly focuses on the weight of the condensate rather than the evaluation of its film-forming barrier performance, all evaluations of condensation fogging involved in the present invention adopt the glossiness method, and the fogging condition of the glass plate surface is also evaluated.

[0005] In order to achieve the low haze requirement for automotive interior trim, many people have also conducted research on its preparation process, raw material selection, additives, etc. However, these methods may focus more on gram weight or numerical value improvement, and do not evaluate the appearance of the glass plate surface, which is not consistent with the performance requirements during actual use (no surface condensation affecting vision, etc.), and there is no clear equivalent relationship between the gloss value and the apparent evaluation of the glass plate. CN 109206744, when modifying PP with talcum powder, reduces the atomization of the material by preferably selecting a low-atomization polypropylene material and adding an adsorbent to achieve the effect of low atomization when tested by gram weight method. This patent is filled with only talcum powder, and there is no description of the influence of other fillers on the atomization performance. At the same time, it is limited by the supply of raw materials or the performance requirements of the formula. When the polypropylene base material is restricted, the selectivity becomes less and the difficulty of formula design becomes greater. Summary of the Invention

[0006] Based on this, the present invention aims to provide a high-performance, low-condensation fogging modified polypropylene and a method for its preparation. This method is simple to operate, reduces the use of talc filler through the use of functional fillers, and maintains the excellent mechanical properties of the modified material through a balanced ratio with the remaining materials. It also exhibits exceptionally high condensation fogging performance, achieving a gloss retention rate exceeding 90% when testing condensation fogging using the SAEJ 1756 gloss method for the prepared parts. Furthermore, the surface of the test glass plate remains clean, free of oil film, oil droplets, and crystallization. This prevents the release of small molecules from automotive accessories during long-term use, which can cause fogging on the glass and obstruct vision.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A high-performance, low-condensation, atomized modified polypropylene is prepared from the following raw materials in percentage by mass:

[0009]

[0010] The polypropylene is a block copolymer polypropylene, which is granular in appearance, has a melt flow rate of 10-60g / 10min, and a simple beam notched impact strength of >3kJ / m at room temperature. 2 .

[0011] The polyethylene high-density polyethylene is granular in appearance and has a melt flow rate of 5-10 g / 10 min.

[0012] The toughening agent is ethylene-octene copolymer.

[0013] The functional filler is basic magnesium sulfate whisker, the whisker diameter is less than 1um, and the length is 10-30um.

[0014] The lubricant is one or a combination of zinc stearate, calcium stearate and magnesium stearate.

[0015] The antioxidant is at least one thioester antioxidant selected from hindered phenols and semi-hindered phenols. More specifically, the thioester antioxidant is DSTP.

[0016] The adsorbent is magnesium silicate, montmorillonite or a combination thereof.

[0017] The method for preparing the high-performance, low-condensation atomized modified polypropylene comprises the following steps:

[0018] (1) Weigh stearate and whiskers according to the material ratio, and stir the whiskers and stearate lubricant evenly. Step (2) Evenly blend the modified whiskers obtained in step (1) with 5-10 parts of polyethylene and add them through the side feed port. The remaining materials enter through the main feed port of the twin-screw extruder, and after being melted, they are mixed with the materials entering the side feed port and extruded, pelletized, dried, and other processes to obtain the finished material; the process parameters of the twin-screw extruder are as follows: zone 1 temperature 60-180°C, zone 2-8 temperature 180-210°C, and extrusion temperature 200±10°C.

[0019] By adding special functional fillers to the formula, the present invention reduces the amount of talc used while effectively maintaining or even significantly improving the material's mechanical properties, heat resistance, and dimensional stability. Furthermore, through the optimized combination of the functional filler with adsorbents, lubricants, antioxidants, and polyethylene, the material effectively reduces the precipitation of small molecules during production and use in high-temperature environments, resulting in parts with gloss retention exceeding 90% when tested using the SAEJ 1756 gloss method for condensation fogging. Compared to conventional talc-modified PP materials, this method achieves the production of a low-condensation fogging modified PP material through optimized formulation design and additive selection. The material exhibits excellent mechanical properties, high resistance to condensation fogging, and a simple and easily implemented production process, making it widely applicable to the production of automotive interior parts. Specific implementation methods

[0020] The present invention is described below by means of specific examples, but the present invention is not limited to these Example

[0021] The main raw materials used in the embodiments and comparative examples are as follows:

[0022] The polypropylene resin is copolymerized polypropylene EP648U;

[0023] The polyethylene resin is high-density polyethylene HDPE 8008;

[0024] The mesh number of talc powder is 5000 mesh;

[0025] The toughening agent is Dow LC168;

[0026] The functional filler basic magnesium sulfate is Yingkou Kangru WS-6VS;

[0027] The processing aid is zinc stearate;

[0028] The antioxidants in the embodiment are hindered phenolic main antioxidant 1010 and thioester auxiliary antioxidant DSTP, with a ratio of 1:1; the antioxidants in the comparative example are 1010:168=1:1;

[0029] The adsorbent is magnesium silicate;

[0030] The formulas of the embodiments and comparative examples are shown in Table 1 below:

[0031] Table 1. Ratio of each sample formula

[0032]

[0033]

[0034] After co-extrusion, the examples and comparative examples were injection molded into standard test specimens and tested according to standards. Density was tested according to ISO 1183; tensile strength was tested according to ISO 527 at a test speed of 50 mm / min; flexural modulus was tested according to ISO 178 at a test speed of 2 mm / min and a span of 64 mm; notched impact strength was tested at 23°C according to ISO 179; and fogging performance was tested according to SAE J 1756. The test glass plates were also evaluated for appearance.

[0035] The performance of Examples 1-5 and Comparative Example 1 is shown in Table 2 below;

[0036] Table 2. Comparison of formula and performance of each sample

[0037]

[0038]

[0039] As can be seen from Examples 1-5 and Comparative Example 1, the optimized combination of functional fillers, adsorbents, lubricants, antioxidants, and polyethylene toughening agents can effectively reduce the precipitation of small molecules during production and use in high-temperature environments while maintaining or even improving the material's original extrusion mechanical properties. The condensation-fog gloss retention rate can exceed 90% in the SAEJ 1756 gloss test, while also preventing the formation of oil film and droplets and crystallization during surface evaluation.

[0040] In Example 1 and Comparative Example 1, the combination of lubricant, antioxidant and adsorbent can not only reduce the frictional heating effect of the material during the production process and reduce the initial decomposition of the material due to heat accumulation, but also promptly decompose the peroxides produced by degradation after the initial decomposition of the material, and at the same time adsorb small molecules, greatly improving the condensation fogging value of the gloss method. Most importantly, it can completely maintain the smoothness of the glass plate surface after the test.

[0041] In Examples 1-3 and Comparative Example 1, the anti-atomization effects of high-density polyethylene and elastomers are significantly superior to those of PP substrates, while basic magnesium sulfate whiskers also significantly outperform mineral talc in resisting condensation atomization and precipitation. Therefore, the optimized combination of functional fillers and HDPE / elastomers can directly enhance the overall material's anti-atomization and condensation effects through formulation. Furthermore, due to the activation of basic magnesium sulfate whiskers by stearate and the excellent properties of the whiskers themselves, increasing the overall whisker ratio can significantly improve the material's flexural modulus, tensile strength, and other properties, while maintaining toughness.

[0042] Compared to Comparative Example 1, Examples 2 and 5 significantly improved the glossiness and condensation fogging values ​​and appearance ratings by reducing talc and increasing the proportions of HDPE, elastomer, and whiskers. Mechanical properties, such as tensile strength and impact strength, were also improved to varying degrees. Furthermore, because the whisker material itself has a lower density than talc, the overall density of the modified material decreased, further meeting the requirements for lightweight automotive component design.

[0043] In the above embodiment, the type of PP substrate can be replaced or matched according to actual needs, and the high requirements of the overall material for condensation atomization can be met by changing the ratio of other substances.

Claims

1. A high-performance low-condensation atomized modified polypropylene, characterized in that: Made from the following raw materials in percentage by mass: Polypropylene 50-80%; Polyethylene 0-10%; Talc 5-20%; Toughener 1-15%; Functional fillers 1-10%; Lubricant 0.2-1%; Antioxidant 0.1-0.5%; Adsorbent 0.2-1%; The functional filler is basic magnesium sulfate whisker, the whisker diameter is less than 1um, and the length is 10-30um.

2. A high-performance, low-condensation atomized modified polypropylene according to claim 1, characterized in that: The polypropylene is a block copolymer polypropylene, which is granular in appearance, has a melt flow rate of 10-60 g / 10min, and a simply supported beam notched impact strength of >3 kJ / m at room temperature. 2 .

3. The high-performance, low-condensation atomized modified polypropylene according to claim 1, characterized in that: The polyethylene high-density polyethylene is granular in appearance and has a melt flow rate of 5-10 g / 10min.

4. The high-performance low-condensation atomized modified polypropylene according to claim 1, characterized in that: The toughening agent is ethylene-octene copolymer.

5. The high-performance low-condensation atomized modified polypropylene according to claim 1, characterized in that: The lubricant is one of zinc stearate, calcium stearate and magnesium stearate or a combination thereof.

6. The high-performance low-condensation atomized modified polypropylene according to claim 1, characterized in that: The antioxidant is selected from at least one of hindered phenol and semi-hindered phenol thioester antioxidants.

7. The high-performance low-condensation atomized modified polypropylene according to claim 6, characterized in that: The thioester antioxidant is DSTP.

8. The high-performance low-condensation atomized modified polypropylene according to claim 1, characterized in that: The adsorbent is magnesium silicate, montmorillonite or a combination thereof.

9. The method for preparing high-performance low-condensation atomized modified polypropylene according to any one of claims 1 to 8, characterized in that: The steps include: (1) Weighing a lubricant and whiskers according to the material ratio, and mixing the whiskers and lubricant evenly; (2) The modified whiskers obtained in step (1) are uniformly blended with 5-10 parts of polyethylene and added through the side feed port; the remaining materials enter through the main feed port of the twin-screw extruder, are melted and mixed with the materials entering through the side feed port, and then extruded, pelletized, and dried to obtain the finished material; the process parameters of the twin-screw extruder are as follows: the temperature of zone 1 is 60-180°C, the temperature of zones 2-8 is 180-210°C, and the extrusion temperature is 200±10°C.

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