Polypropylene composition and use thereof

Abstract

The application discloses a polypropylene composition and application thereof, and belongs to the technical field of high polymer materials. The product is prepared by using a specific type of polypropylene resin and ethylene copolymer elastomer as a base resin, and simultaneously compounding a specific type of environmental resistance additive, so that the product can not only achieve ideal light transmittance, but also has high toughness, and can be applied to the preparation of automobile parts; meanwhile, the light transmittance of the product has long-term stability and heat resistance, and the comprehensive performance is excellent.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a polypropylene composition and application thereof. Background Art

[0002] As a thermoplastic polymer with high mechanical strength and high environmental stability, polypropylene is very popular in automotive parts, especially decorative parts.

[0003] However, traditional polypropylene decorative parts are mostly opaque. With increasing user experience demands, attempts have begun to develop polypropylene decorative products with light-transmitting properties. Existing polypropylene products typically employ transparent nucleating agents or the introduction of ethylene monomers to reduce the crystallinity or spherulite size of the polypropylene molecules, thereby enhancing light transmission. However, such practices often result in products with insufficient mechanical properties, particularly toughness that falls short of automotive component requirements. Furthermore, the stability of these products' light transmission cannot be guaranteed. Prolonged use or exposure to high temperatures may result in the product losing its normal light transmittance. Summary of the Invention

[0004] Based on the defects of the existing technology, the purpose of the present invention is to provide a polypropylene composition. This product uses a specific type of polypropylene resin and an ethylene copolymer elastomer as a base resin, and is compounded with a specific type of environmentally resistant additive. It can not only achieve ideal light transmittance, but also has high toughness, which is sufficient for application in the preparation of automotive parts. At the same time, the light transmittance of the product has long-term stability and heat resistance, and the overall performance is excellent.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A polypropylene composition comprising the following components in parts by weight:

[0007] 69-86 parts of polypropylene resin, 15-30 parts of ethylene copolymer elastomer, 0.5-2 parts of environmental resistance additive;

[0008] The polypropylene resin and ethylene copolymer elastomer meet the following requirements: A≤45g / 10min, B≤0.01;

[0009] Where A=|a1-a2|;

[0010] B=|b1-b2|;

[0011] a1 is the melt flow rate of the polypropylene resin at 230° C. and a load of 2.16 kg according to ISO 1133-2011; a2 is the melt flow rate of the ethylene copolymer elastomer at 230° C. and a load of 2.16 kg according to ISO 1133-2011;

[0012] b1 is the refractive index of the polypropylene resin at 23°C, and b2 is the refractive index of the ethylene copolymer elastomer at 23°C;

[0013] The environmental resistance auxiliary agent is a mixture of a semi-hindered phenol antioxidant, a phosphite antioxidant and a benzophenone light stabilizer.

[0014] In the prior art, in order to introduce the newly added light transmittance characteristic of modified polypropylene resin, it is necessary to destroy the molecular chain regularity of the semi-crystalline polypropylene molecules to a certain extent, hindering its crystallization behavior. This increases the overall amorphous region, making it easier for light to pass through the product after exposure, thereby achieving light transmittance. However, in existing products, people often fail to consider that destroying the molecular chains of the polypropylene molecules will weaken the overall molecular chain entanglement and reduce the mechanical properties of the product. In order to retain the toughness required for application in automotive parts, the inventors blended an ethylene copolymer elastomer with a polypropylene resin in the product described in the present invention to enhance the light transmittance of the product. At the same time, they studied the fluidity and refractive index of the two components. They creatively discovered that by selecting a polypropylene resin and an ethylene copolymer elastomer with a certain degree of fluidity and refractive index for compounding in a specific ratio, the ethylene copolymer elastomer will be distributed in the product in a flat, stringy manner, further reducing light scattering and refraction. In addition, the component has a good dispersion effect and can also provide sufficient toughness to the product. The same effect cannot be achieved by selecting other types of light transmittance modifiers.

[0015] On the other hand, in the product system, in order to ensure that the product can still achieve sufficient light transmittance when it is left stationary for a long time and at high temperatures, the inventors have screened and found that only when a mixture of semi-hindered phenol antioxidants, phosphite antioxidants and benzophenone light stabilizers is introduced into the product as an environmental resistance additive, the product can achieve the expected effect, and thus can be used in the preparation of light-transmitting automotive parts with higher environmental requirements.

[0016] Preferably, A=0~45g / 10min, B=0~0.01.

[0017] More preferably, A=0~45g / 10min, B=0~0.0075.

[0018] Preferably, the polypropylene composition comprises the following components in parts by weight: 75-80 parts of polypropylene resin, 20-25 parts of ethylene copolymer elastomer, and 0.6-0.8 parts of environmental resistance additive.

[0019] Preferably, the polypropylene resin is homopolypropylene.

[0020] More preferably, in the polypropylene composition, the mass content of the polypropylene resin is ≥50 wt%.

[0021] More preferably, the polypropylene resin has a melt flow rate of 25-60 g / 10 min at 230° C. and a load of 2.16 kg.

[0022] More preferably, the melt flow rate of the polypropylene resin at 230° C. and a load of 2.16 kg is within the range of one or any two of 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 50 g / 10 min, 55 g / 10 min, and 60 g / min.

[0023] Preferably, the refractive index of the polypropylene resin at 23° C. is 1.4950-1.4980.

[0024] The refractive index of polypropylene resin is tested using the refractometer method specified in GB / T39691-2020. Specifically, a drop of contact plastic is placed on the polished surface of an 8×20×5 mm transparent sheet sample, with the polished edge of the sample facing the light source. The sample is placed against the prism surface until half of the eyepiece field is dark. The compensator is then adjusted until all color is removed from the field. The index arm is then adjusted with a vernier so that the dividing line between the bright and dark areas coincides with the intersection of the eyepiece crosshairs. The refractive index value is then read from the instrument scale. This is repeated for five samples, and the average value is taken to determine the refractive index of the polypropylene resin.

[0025] Preferably, the ethylene copolymer elastomer is at least one of ethylene-octene copolymer, ethylene-propylene copolymer, and styrene-ethylene-butylene-styrene copolymer;

[0026] More preferably, the ethylene copolymer elastomer has a melt flow rate of 10 to 25 g / 10 min at 230° C. and a load of 2.16 kg.

[0027] More preferably, the melt flow rate of the ethylene copolymer elastomer at 230° C. and under a load of 2.16 kg is in the range of one or any two of 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, and 25 g / 10 min.

[0028] Preferably, the refractive index of the ethylene copolymer elastomer at 23° C. is 1.4750-1.4950.

[0029] The refractive index of the ethylene copolymer elastomer is tested by the refractometer method in GB / T39691-2020, and the steps are the same as described above.

[0030] Preferably, in the environmental resistance additive, the ratio of the sum of the mass of the semi-hindered phenol antioxidant and the phosphite antioxidant to the mass of the benzophenone light stabilizer is m(semi-hindered phenol antioxidant+phosphite antioxidant):m(benzophenone light stabilizer)=(1:1)~(1:5).

[0031] More preferably, the ratio of the sum of the mass of the semi-hindered phenol antioxidant and the phosphite antioxidant to the mass of the benzophenone light stabilizer is m(semi-hindered phenol antioxidant+phosphite antioxidant):m(benzophenone light stabilizer)=(1:2)~(1:3).

[0032] More preferably, the mass ratio of the semi-hindered phenol antioxidant to the phosphite antioxidant is (0.8-1.2): (0.8-1.2).

[0033] More preferably, the semi-hindered phenol antioxidant includes at least one of 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione and 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane.

[0034] More preferably, the phosphite antioxidant includes at least one of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate and tris[2,4-di-tert-butylphenyl]phosphite.

[0035] More preferably, the benzophenone-based light stabilizer includes at least one of 2-hydroxy-4-n-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-decyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, and 5-chloro-2-hydroxy-benzophenone.

[0036] After screening, it was found that when the antioxidant component and the benzophenone light stabilizer in the environmental resistance additive are preferably within the above range, the product can achieve a better comprehensive light transmittance effect.

[0037] It should be noted that the components of the product of the present invention also include 0.01 to 1 parts of processing aids. More preferably, the processing aids include lubricants, antistatic agents, etc. Those skilled in the art can add them according to actual needs as long as they do not affect the expected technical effects of the product of the present invention.

[0038] Another object of the present invention is to provide a method for preparing the polypropylene composition, comprising the following steps:

[0039] After the components are uniformly mixed, they are melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

[0040] The preparation method of the polypropylene composition of the present invention has simple operating steps and can realize industrial-scale production.

[0041] Preferably, the temperature range of the screw extruder is set to: 80~230°C, the screw speed is 400~600r / min, and the screw length-to-diameter ratio is (38~42):1.

[0042] Another object of the present invention is to provide use of the polypropylene composition in preparing transparent automotive decorative parts.

[0043] Preferably, the transparent automobile decorative parts include automobile decorative lampshades and automobile bumpers.

[0044] The polypropylene composition of the present invention can achieve high toughness. At the same time, the product has low crystallinity and good light transmittance. Under the selection of environmentally resistant additives and its own formula ratio, the light transmittance also has ideal environmental stability. Therefore, it is very suitable for the preparation of automotive decorative parts with complex usage scenarios.

[0045] The beneficial effect of the present invention is that the present invention provides a polypropylene composition. By using a specific type of polypropylene resin and an ethylene copolymer elastomer as a base resin, and compounding a specific type of environmentally resistant additive, the product can not only achieve ideal light transmittance, but also has high toughness, which is sufficient for application in the preparation of automotive parts; at the same time, the light transmittance of the product has long-term stability and heat resistance, and the overall performance is excellent. DETAILED DESCRIPTION

[0046] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and comparative examples. Its purpose is to understand the content of the present invention in detail, rather than to limit the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative work premise all fall within the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention are all conventional common reagents and instruments unless otherwise specified.

[0047] Examples 1 to 16

[0048] The embodiments of the polypropylene composition of the present invention include components of the polypropylene composition as shown in Table 1.

[0049] The preparation method of the product comprises the following steps:

[0050] The components are mixed evenly, and then placed into a screw extruder for melt extrusion and granulation to obtain the halogen-free flame-retardant polypropylene composition.

[0051] The temperature zones of the screw extruder are set to: zone 1: 80°C, zone 2: 190°C, zone 3: 200°C, zone 4: 200°C, zone 5: 200°C, zone 6: 200°C, zone 7: 210°C, zone 8: 210°C, zone 9: 220°C, zone 10: 220°C, the screw speed is 500r / min, and the aspect ratio is 40:1.

[0052] Comparative Examples 1 to 17

[0053] The difference between the comparative examples and the examples is only in the types and proportions of the components, as shown in Table 2.

[0054] Among the components described in each embodiment and comparative example,

[0055] Polypropylene resin 1: melt flow rate at 230°C and 2.16 kg load is 55 g / 10 min, refractive index at 23°C is 1.4950, homopolymer polypropylene, Zhenhai Refining and Chemical, PPM60T;

[0056] Polypropylene resin 2: melt flow rate at 230°C and 2.16 kg load is 32 g / 10 min, refractive index at 23°C is 1.4971, homopolymer polypropylene, Sinopec, PP320;

[0057] Polypropylene resin 3: melt flow rate at 230°C and 2.16 kg load is 25 g / 10 min, refractive index at 23°C is 1.4960, homopolymer polypropylene, Sinopec, PPSZ30S;

[0058] Polypropylene resin 4: melt flow rate at 230°C, 2.16 kg load: 150 g / 10 min, refractive index at 23°C: 1.5055, copolymerized polypropylene, Korean SK, PP BX3950;

[0059] Polypropylene resin 5: melt flow rate of 65 g / 10 min at 230°C and 2.16 kg load, refractive index of 1.5150 at 23°C, block copolymer polypropylene, CNOOC Shell, PPEP648U;

[0060] Polypropylene resin 6: melt flow rate of 12 g / 10 min at 230°C and 2.16 kg load, refractive index of 1.5000 at 23°C, random copolymer polypropylene, Sinopec, PPUT8012M;

[0061] Polypropylene resin 7: melt flow rate at 230°C, 2.16 kg load: 50 g / 10 min, refractive index at 23°C: 1.5050, homopolymer polypropylene, Sinopec, PPH650 powder;

[0062] Polypropylene resin 8: melt flow rate at 230°C and 2.16 kg load is 150 g / 10 min, refractive index at 23°C is 1.4971, homopolymer polypropylene, Sinopec, PPH-MN150;

[0063] Ethylene copolymer elastomer 1: melt flow rate at 230°C and 2.16 kg load is 10 g / 10 min, refractive index at 23°C is 1.4900, ethylene-octene copolymer, Dow Chemical, POE 8200;

[0064] Ethylene copolymer elastomer 2: melt flow rate at 230°C, 2.16 kg load: 20 g / 10 min, refractive index at 23°C: 1.4950, ethylene-propylene copolymer, ExxonMobil, Vistamaxx 6202;

[0065] Ethylene copolymer elastomer 3: melt flow rate at 230°C and 2.16 kg load is 25 g / 10 min, refractive index at 23°C is 1.4960, styrene-ethylene-butylene-styrene copolymer, Kraton Polymer Trading (China) Co., Ltd., SEBS1643;

[0066] Ethylene copolymer elastomer 4: melt flow rate at 230°C and 2.16 kg load is 3 g / 10 min, refractive index at 23°C is 1.4805, ethylene-octene copolymer, Dow Chemical, POE 8180;

[0067] Ethylene copolymer elastomer 5: melt flow rate at 230°C and 2.16 kg load is 11 g / 10 min, refractive index at 23°C is 1.4990, styrene-ethylene-propylene block copolymer, Kraton Polymer Trading (China) Co., Ltd., SEPSG1730;

[0068] Ethylene copolymer elastomer 6: melt flow rate at 230°C, 2.16 kg load: 30 g / 10 min, refractive index at 23°C: 1.5100, styrene-ethylene-ethylene-propylene-styrene copolymer, Kraton Polymer Trading (China) Co., Ltd., SEEPS G1750;

[0069] Ethylene copolymer elastomer 7: melt flow rate at 230°C and 2.16 kg load is 0.8 g / 10 min, refractive index at 23°C is 1.4900, ethylene-octene copolymer, Dow Chemical, POE8677;

[0070] Primary antioxidant 1: semi-hindered phenolic antioxidant, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, commercially available as RIANOX 1790;

[0071] Primary antioxidant 2: semi-hindered phenol antioxidant, 3,9-bis[1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, Japan Aidico, AO-80;

[0072] Primary antioxidant 3: hindered phenol antioxidant, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, BASF, Germany, antioxidant 1010;

[0073] Primary antioxidant 4: diaryl secondary amine antioxidant, 4,4'-bis(phenylisopropyl)diphenylamine, SI Group, NAUGARD 445;

[0074] Secondary antioxidant 1: phosphite antioxidant, tris[2,4-di-tert-butylphenyl]phosphite, BASF, Germany, SONOX 168;

[0075] Auxiliary antioxidant 2: phosphite antioxidant, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate, Aidico, PEP-36;

[0076] Secondary antioxidant 3: sulfur antioxidant, pentaerythritol tetra(3-laurylthiopropionate), Aidico, AO-412S;

[0077] Light stabilizer 1: hindered amine light stabilizer, 2,2,6,6-tetramethyl-4-piperidinyl stearate, UV-3853, commercially available;

[0078] Light stabilizer 2: Benzophenone light stabilizer, 2-hydroxy-4-n-octyloxy-benzophenone, BASF, Germany, UV-531;

[0079] Light stabilizer 3: Triazine light stabilizer, 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-octyloxyphenol, BASF, Germany, UV-1164

[0080] Unless otherwise specified, the components and raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all the same.

[0081] Table 1

[0082]

[0083] Table 2

[0084]

[0085] Effect Example 1

[0086] In order to verify the performance of the products of the present invention, the products of each embodiment and comparative example were subjected to the following performance tests, and the specific steps are as follows:

[0087] (1) Simply supported beam notched impact strength: tested in accordance with ISO180-2019 standard, type A notch.

[0088] (2) Light transmittance: Tested in accordance with GB / T 2410-2008: Using light source A and haze meter method A, the sample was injection-molded into a square plate (100 mm × 100 mm × 3 mm) to test the light transmittance under normal conditions.

[0089] (3) Heat stability of light transmittance: According to GB / T 39822-2021, each sample after the test in step (2) was heat treated at 120°C for 1500 h, and then the light transmittance test of the sample in step (2) was repeated. The light transmittance retention rate of the sample was calculated using the formula: light transmittance of the sample after heat treatment / initial normal light transmittance × 100%.

[0090] (4) Transmittance aging test: According to the experimental method of PV3929, the sample is placed in the 300~400nm band with an irradiance of 60W / m 2 The sample was subjected to light aging for 1500 hours under a xenon lamp, and then the light transmittance test of step (2) was repeated to calculate the light transmittance retention rate of the sample. The calculation formula was: light transmittance of the sample after light aging treatment / initial normal light transmittance × 100%.

[0091] The test results are shown in Tables 3 and 4.

[0092] Table 3

[0093]

[0094] Table 4

[0095]

[0096] As can be seen from Tables 3 and 4, the product of the present invention can achieve at least 30 kJ / m 2 The product exhibits high impact strength and can achieve a light transmittance of at least 60% at a normal depth of 3mm. Furthermore, the product exhibits high light transmittance stability. After long-term exposure to heat, the product's light transmittance retention remains above 90%. Furthermore, after long-term aging treatment using a xenon lamp, the light transmittance retention also remains above 90%, demonstrating low attenuation. A comparison of Example 6 with Examples 14-16 reveals that the ratio of the antioxidant and light stabilizer in the environmentally resistant additives in the product of the present invention has a certain influence on the stability of the product's light transmittance. When the ratio of the antioxidant and light stabilizer is maintained within the range of (1:2) to (1:3), the product's light transmittance stability is even higher.

[0097] In contrast, in the comparative examples, since the selection of the polypropylene resin and the ethylene copolymer elastomer does not meet the limitations of parameters A and B, as shown in the products of Comparative Examples 1 to 10, or the type of environmentally resistant additive is improperly selected, as shown in the products of Comparative Examples 11 to 15, the products are unable to achieve the desired toughness, transmittance, and transmittance stability. At the same time, according to Example 6, Examples 2 to 4, and Comparative Examples 16 to 17, it can be seen that as the ratio of the polypropylene resin and the ethylene copolymer elastomer in the polypropylene composition changes, not only the toughness of the product changes, but also the transmittance and transmittance stability change. Only when the ratio is appropriate can the product achieve the expected technical effect.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composition, characterized in that The composition comprises the following components in parts by weight: 69-86 parts of polypropylene resin, 15-30 parts of ethylene copolymer elastomer, 0.5-2 parts of environmental resistance additive; The polypropylene resin and ethylene copolymer elastomer meet the following requirements: A≤45g / 10min, B≤0.01; Where A=|a1-a2|; B=|b1-b2|; a1 is the melt flow rate of the polypropylene resin at 230° C. and a load of 2.16 kg according to ISO 1133-2011; a2 is the melt flow rate of the ethylene copolymer elastomer at 230° C. and a load of 2.16 kg according to ISO 1133-2011; b1 is the refractive index of the polypropylene resin at 23°C, and b2 is the refractive index of the ethylene copolymer elastomer at 23°C; The environmental resistance additive is a mixture of a semi-hindered phenol antioxidant, a phosphite antioxidant and a benzophenone light stabilizer; in the environmental resistance additive, the ratio of the sum of the mass of the semi-hindered phenol antioxidant and the phosphite antioxidant to the mass of the benzophenone light stabilizer is m (semi-hindered phenol antioxidant + phosphite antioxidant): m (benzophenone light stabilizer) = (1:1) to (1:5).

2. The polypropylene composition according to claim 1, wherein The polypropylene resin is homopolymer polypropylene.

3. The polypropylene composition according to claim 2, wherein The melt flow rate of the polypropylene resin at 230° C. and a load of 2.16 kg is 25-60 g / 10 min; the refractive index of the polypropylene resin at 23° C. is 1.4950-1.4980.

4. The polypropylene composition according to claim 1, wherein The ethylene copolymer elastomer is at least one of ethylene-octene copolymer, ethylene-propylene copolymer, and styrene-ethylene-butylene-styrene copolymer.

5. The polypropylene composition according to claim 4, wherein The melt flow rate of the ethylene copolymer elastomer at 230° C. and a load of 2.16 kg is 10-25 g / 10 min; the refractive index of the ethylene copolymer elastomer at 23° C. is 1.4750-1.4950.

6. The method for preparing the polypropylene composition according to any one of claims 1 to 5, wherein: The following steps are involved: After the components are uniformly mixed, they are melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

7. Use of the polypropylene composition according to any one of claims 1 to 5 in the preparation of transparent automotive decorative parts.

8. The use according to claim 7, characterized in that The transparent automobile decorative parts include automobile decorative lampshades and automobile bumpers.

9. An automobile decorative component, characterized in that: The polypropylene composition comprises the polypropylene composition according to any one of claims 1 to 5.

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