Polypropylene composition and application thereof

Abstract

The invention discloses a polypropylene composition and application thereof, and belongs to the technical field of high polymer materials, and the polypropylene composition is prepared by using a specific type of polypropylene resin matched with an ethylene copolymer elastomer as matrix resin and compounding a specific type of environment-resistant auxiliary agent, so that ideal light transmission can be realized, the toughness is relatively high, and the service life of the polypropylene composition is prolonged. The preparation method can be applied to 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 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 widely used in automotive parts, especially decorative parts.

[0003] However, most traditional polypropylene decorative parts are opaque products. With the improvement of user experience, people have begun to try to prepare some polypropylene decorative products with light transmission ability. In existing polypropylene products, transparent nucleating agents or the introduction of ethylene monomer modification are usually used to reduce the crystallinity or spherulite size of polypropylene molecules, so that the products have light transmission. However, such practices often result in products that do not have sufficient mechanical properties, especially the toughness of the products does not meet the requirements of automotive parts; on the other hand, the light transmission stability of these products cannot be guaranteed. Once the products are used for too long or exposed to some higher temperatures, the products may not be able to maintain normal light transmittance. Summary of the invention

[0004] Based on the defects of the prior art, 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 comprehensive performance is excellent.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: A polypropylene composition comprising 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 resistant 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 2.16 kg load according to ISO1133-2011 standard, and a2 is the melt flow rate of the ethylene copolymer elastomer at 230° C. and 2.16 kg load according to ISO1133-2011 standard; 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 auxiliary agent is a mixture of a semi-hindered phenol antioxidant, a phosphite antioxidant and a benzophenone light stabilizer.

[0006] In the prior art, in order to introduce the newly added light transmittance characteristics of the polypropylene resin after modification, it is necessary to destroy the molecular chain regularity of the semi-crystalline polypropylene molecules to a certain extent, hinder its crystallization behavior, increase the overall amorphous area, and make it easier for light to penetrate after irradiating the product, thereby achieving light transmittance. However, in the existing products, people often do not consider that after destroying the molecular chain of the polypropylene molecules, the overall molecular chain entanglement is weakened, and the mechanical properties of the product will also decrease. In order to retain the toughness performance required for application in automotive parts, the inventors blended ethylene copolymer elastomer and polypropylene resin in the product of the present invention to improve the light transmittance of the product, and at the same time studied the fluidity and refractive index of the two components. It is creatively found that as long as the polypropylene resin and ethylene copolymer elastomer with fluidity and refractive index close to a certain degree are selected for compounding at a specific ratio, the ethylene copolymer elastomer will be distributed in the product in a flat wire-like shape, further reducing light scattering and refraction, and the dispersion effect of the component is good, which can bring sufficient toughness to the product at the same time, while the same effect cannot be achieved by selecting other types of light transmittance modifiers.

[0007] 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 temperature, 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 can thus be used in the preparation of light-transmitting automotive parts with higher environmental requirements.

[0008] Preferably, A=0~45g / 10min, B=0~0.01.

[0009] Further preferably, A=0~45g / 10min, B=0~0.0075.

[0010] 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 environmentally resistant additive.

[0011] Preferably, the polypropylene resin is homopolypropylene.

[0012] More preferably, in the polypropylene composition, the mass content of the polypropylene resin is ≥50wt%.

[0013] More preferably, the melt flow rate of the polypropylene resin at 230° C. and a load of 2.16 kg is 25 to 60 g / 10 min.

[0014] More preferably, the melt flow rate of the polypropylene resin at 230° C. and 2.16 kg load is in 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.

[0015] Preferably, the refractive index of the polypropylene resin at 23° C. is 1.4950-1.4980.

[0016] The test method for the refractive index of the polypropylene resin is the refractometer method in GB / T39691-2020. Specifically, a drop of contact plastic liquid is dropped on the polished surface of a transparent sheet sample of 8×20×5 mm, with the polished edge of the sample facing the light source, and the prism surface is adjusted to half of the eyepiece field dark. Then adjust the compensator until all colors are removed from the field, and then use the cursor to adjust the index arm so that the dividing line between the bright and dark parts coincides with the intersection of the eyepiece cross. At this time, read the refractive index value from the instrument scale, repeat 5 samples, and take the average value, which is the refractive index of the polypropylene resin.

[0017] Preferably, the ethylene copolymer elastomer is at least one of ethylene-octene copolymer, ethylene-propylene copolymer, and styrene-ethylene-butylene-styrene copolymer; More preferably, the melt flow rate of the ethylene copolymer elastomer at 230° C. and a load of 2.16 kg is 10 to 25 g / 10 min.

[0018] More preferably, the melt flow rate of the ethylene copolymer elastomer at 230° C. and 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.

[0019] Preferably, the refractive index of the ethylene copolymer elastomer at 23° C. is 1.4750-1.4950.

[0020] The test method for the refractive index of the ethylene copolymer elastomer is the refractometer method in GB / T39691-2020, and the steps are the same as described above.

[0021] Preferably, in the environmentally resistant 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).

[0022] 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).

[0023] More preferably, the mass ratio of the semi-hindered phenol antioxidant to the phosphite antioxidant is (0.8-1.2):(0.8-1.2).

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] Another object of the present invention is to provide a method for preparing the polypropylene composition, comprising the following steps: After the components are uniformly mixed, they are melt-extruded and granulated in a screw extruder to obtain the polypropylene composition.

[0030] The preparation method of the polypropylene composition of the present invention has simple operation steps and can realize industrial-scale production.

[0031] Preferably, the temperature range of the screw extruder is set to: 80~230°C, the screw speed is 400~600r / min, and the screw aspect ratio is (38~42):1.

[0032] Another object of the present invention is to provide application of the polypropylene composition in preparing transparent automobile decorative parts.

[0033] Preferably, the transparent automobile decorative parts include automobile decorative lampshades and automobile bumpers.

[0034] The polypropylene composition of the present invention can achieve higher 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.

[0035] The beneficial effect of the present invention is that the present invention provides a polypropylene composition, which, 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, 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 comprehensive performance is excellent. DETAILED DESCRIPTION

[0036] 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, the purpose of which 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 belong to the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention, unless otherwise specified, are all commonly used common reagents and instruments.

[0037] Embodiments 1 to 16 The embodiments of the polypropylene composition of the present invention include components of the polypropylene composition as shown in Table 1.

[0038] The preparation method of the product comprises the following steps: The components are mixed evenly, and then placed in a screw extruder for melt extrusion and granulation to obtain the halogen-free flame-retardant polypropylene composition.

[0039] The temperature zones of the screw extruder are set as: 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.

[0040] Comparative Examples 1 to 17 The difference between the comparative examples and the embodiments is only in the types and proportions of components, as shown in Table 2.

[0041] Among the components described in each embodiment and comparative example, Polypropylene resin 1: melt flow rate at 230°C and 2.16kg load is 55g / 10min, refractive index at 23°C is 1.4950, homopolymer polypropylene, Zhenhai Refining and Chemical, PPM60T; 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; 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; Polypropylene resin 4: melt flow rate at 230°C and 2.16 kg load is 150 g / 10 min, refractive index at 23°C is 1.5055, copolymer polypropylene, Korean SK, PP BX3950; Polypropylene resin 5: melt flow rate at 230°C and 2.16 kg load is 65 g / 10 min, refractive index at 23°C is 1.5150, block copolymer polypropylene, CNOOC Shell Company, PPEP648U; Polypropylene resin 6: melt flow rate at 230°C and 2.16kg load is 12g / 10min, refractive index at 23°C is 1.5000, random copolymer polypropylene, Sinopec, PPUT8012M; Polypropylene resin 7: melt flow rate at 230°C and 2.16kg load is 50g / 10min, refractive index at 23°C is 1.5050, homopolymer polypropylene, Sinopec, PPH650 powder; 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; 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; Ethylene copolymer elastomer 2: melt flow rate at 230°C, 2.16 kg load is 20 g / 10 min, refractive index at 23°C is 1.4950, ethylene-propylene copolymer, ExxonMobil, Vistamaxx 6202; 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; 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; 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; Ethylene copolymer elastomer 6: melt flow rate at 230°C and 2.16 kg load is 30 g / 10 min, refractive index at 23°C is 1.5100, styrene-ethylene-ethylene-propylene-styrene copolymer, Kraton Polymer Trading (China) Co., Ltd., SEEPS G1750; 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; Primary antioxidant 1: semi-hindered phenol 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; 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; Main antioxidant 3: hindered phenol antioxidant, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, BASF, Germany, antioxidant 1010; Primary antioxidant 4: diaryl secondary amine antioxidant, 4,4'-bis(phenylisopropyl)diphenylamine, St. Lawrence, NAUGARD 445; Co - antioxidant 1: phosphite antioxidant, tris(2,4 - di - tert - butylphenyl)phosphite, BASF, Germany, SONOX 168; Co - antioxidant 2: phosphite antioxidant, bis(2,6 - di - tert - butyl - 4 - methylphenyl)pentaerythritol diphosphite, Adeka, PEP - 36; Co - antioxidant 3: sulfur antioxidant, pentaerythritol tetrakis(3 - laurylthiopropionate), Adeka, AO - 412S; Light stabilizer 1: hindered amine light stabilizer, 2,2,6,6 - tetramethyl - 4 - piperidyl stearate, UV - 3853, commercially available; Light stabilizer 2: benzophenone light stabilizer, 2 - hydroxy - 4 - n - octyloxybenzophenone, BASF, Germany, UV - 531; 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 Unless otherwise specified, the component raw materials used in each example and comparative example of the present invention are commercially available raw materials for processing aids such as antioxidants and lubricants, and the component raw materials used in each parallel experiment are of the same kind.

[0042] Table 1 Table 2 Effect Example 1 To verify the performance of the products described in the present invention, the products of each example and comparative example were subjected to the following performance tests. The specific steps are as follows: (1) Notched Izod impact strength: Tested in accordance with the ISO180 - 2019 standard, Type A notch.

[0043] (2) Transmittance: Tested in accordance with the GB / T 2410 - 2008 standard: Using light source A, selecting Method A, the haze meter method, and testing the transmittance of the sample injection - molded square plate (100mm×100mm×3mm) under normal conditions.

[0044] (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 to calculate the retention rate of the light transmittance of the sample. The calculation formula is: light transmittance of the sample after heat treatment / initial normal light transmittance × 100%.

[0045] (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 h 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%.

[0046] The test results are shown in Tables 3 and 4.

[0047] Table 3 Table 4 As can be seen from Tables 3 and 4, in the product of the present invention, due to the selection of specific polypropylene resin, ethylene copolymer elastomer and environmentally resistant additive, the product can not only achieve at least 30 kJ / m 2 The impact strength of the product can be improved, and at least 60% transmittance can be achieved under the normal condition of 3mm. At the same time, the transmittance of the product has high stability. After long-term treatment in a thermal environment, the transmittance retention rate of the product can still be maintained at more than 90%, and after long-term aging treatment with a xenon lamp, the transmittance retention rate can also be maintained at more than 90%, with a low degree of attenuation. Among them, according to the comparison between Example 6 and Examples 14 to 16, it can be seen that in the product of the present invention, the formula ratio of the antioxidant and the light stabilizer in the environmental resistant additive has a certain influence on the stability of the product transmittance. When the ratio of the two is maintained in the range of (1:2) to (1:3), the transmittance stability of the product is higher.

[0048] 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 cannot achieve the ideal 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 under the appropriate ratio can the product achieve the expected technical effect.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution 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 resistant 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 2.16 kg load according to ISO1133-2011 standard, and a2 is the melt flow rate of the ethylene copolymer elastomer at 230° C. and 2.16 kg load according to ISO1133-2011 standard; 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 auxiliary agent is a mixture of a semi-hindered phenol antioxidant, a phosphite antioxidant and a benzophenone light stabilizer.

2. The polypropylene composition according to claim 1, characterized in that The polypropylene resin is homopolymer polypropylene.

3. The polypropylene composition according to claim 2, characterized in that The melt flow rate of the polypropylene resin at 230° C. and 2.16 kg load 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, characterized in that 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, characterized in that The melt flow rate of the ethylene copolymer elastomer at 230° C. and 2.16 kg load is 10-25 g / 10 min; the refractive index of the ethylene copolymer elastomer at 23° C. is 1.4750-1.4950.

6. The polypropylene composition according to claim 1, characterized in that In the environmentally resistant additive, the mass 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).

7. The method for preparing the polypropylene composition according to any one of claims 1 to 6, characterized in that: 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.

8. Use of the polypropylene composition according to any one of claims 1 to 6 in the preparation of transparent automobile decorative parts.

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

10. An automobile decorative component, characterized in that: The invention comprises the polypropylene composition according to any one of claims 1 to 6.

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