Polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a polypropylene composite material as well as a preparation method and application thereof, and relates to the technical field of high polymer material modification. The invention provides a polypropylene composite material. The polypropylene composite material comprises the following components in parts by weight: 45-80 parts of polypropylene resin, 10-25 parts of an elastomer, 10-25 parts of talcum powder and 0.2-1 part of an antioxidant, wherein the elastomer is composed of a POE elastomer and SEBS; the particle size of the rubber phase of the POE elastomer in the polypropylene composite material is 2-10 [mu] m, and the particle size of the rubber phase of the SEBS is 50-300 nm. According to the present invention, the specifically selected POE elastomer and SEBS compounding method enables the rigidity / paint permeability of the material surface to achieve the optimal balance, such that the material surface and the paint layer are endowed with the optimal physical anchoring force, and the material can pass the harsh high-temperature high-pressure flushing paint adhesion force test.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material modification, in particular to a polypropylene composite material and a preparation method and application thereof. Background Art

[0002] Polypropylene materials have the advantages of low density, excellent mechanical properties, environmental protection, recyclability and high cost performance, and are widely used in various fields such as automobiles and household appliances. With the development of the automobile industry, the requirements for energy conservation and emission reduction are getting higher and higher. The lightweight of new automobile materials is an important means of energy conservation and emission reduction. Therefore, low-density polypropylene materials gradually replace engineering plastics such as nylon, polyester, and ABS, and are increasingly widely used in automobile interior and exterior decoration and engine peripheral parts.

[0003] Especially for car bumpers, all are now made of polypropylene, which has excellent low-temperature toughness and paint adhesion. However, polypropylene is a non-polar material, while car bumper paint is a polar substance. At present, in order to ensure that the paint film does not fall off after high-temperature and high-pressure water flushing, the polypropylene material used for car bumpers must be flame treated before painting to increase the surface polarity and thus improve its paint adhesion.

[0004] The flame treatment process poses a safety hazard in the production workshop. Therefore, the development of polypropylene composite materials without flame treatment is imminent. Summary of the invention

[0005] Based on this, the purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a polypropylene composite material that does not require flame treatment and has excellent paint adhesion, as well as a preparation method and application thereof.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a polypropylene composite material, comprising the following components in parts by weight: 45-80 parts of polypropylene resin, 10-25 parts of elastomer, 10-25 parts of talc powder, and 0.2-1 part of antioxidant; wherein the elastomer is composed of POE elastomer and SEBS (hydrogenated styrene-butadiene-styrene triblock copolymer); the rubber phase particle size of the POE elastomer in the polypropylene composite material is 2-10 μm, and the rubber phase particle size of the hydrogenated styrene-butadiene-styrene triblock copolymer is 50-300 nm.

[0007] The present invention adopts a method of compounding a specifically selected POE elastomer and a hydrogenated styrene-butadiene-styrene triblock copolymer. SEBS has good rigidity, and the POE elastomer can form a paint penetration channel. The combination of the two is more conducive to the paint penetrating into the material surface to form a physical anchoring connection, so that the rigidity of the material surface and the paint permeability reach the best balance, thereby giving the material surface and the paint layer the best physical anchoring connection, and can pass the harsh high-temperature and high-pressure water flushing paint adhesion test.

[0008] Preferably, the weight percentage of the PP resin in the polypropylene composite material is not less than 40%.

[0009] Preferably, the weight percentage of the POE elastomer in the polypropylene composite material is not less than 3%.

[0010] Preferably, the polypropylene composite material comprises the following components in parts by weight: 60-70 parts of polypropylene resin, 15-20 parts of elastomer, 15-20 parts of talc, and 0.2-1 part of antioxidant.

[0011] In one embodiment, the weight of the polypropylene resin is 45 parts, 48 ​​parts, 50 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, or any two of the range values; the weight of the elastomer is 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, or any two of the range values; the talc is 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, or any two of the range values; the antioxidant is 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or any two of the range values.

[0012] Preferably, the rubber phase particle size of the POE elastomer in the polypropylene composite material is 4-6 μm, and the rubber phase particle size of the SEBS is 100-200 nm.

[0013] In one embodiment, the rubber phase particle size of the POE elastomer is in the range of one or any two of 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm; the rubber phase particle size of the SEBS is in the range of one or any two of 50nm, 80nm, 100nm, 150nm, 200nm, 250nm, 300nm.

[0014] In one embodiment, the testing method for the rubber phase particle size of the POE elastomer or SEBS is as follows: the sample is prepared by ultrathin sectioning under liquid nitrogen freezing, the sample thickness is controlled at 50 microns, the elastomer phase is stained with ruthenium trichloride, and then a scanning transmission electron microscope (STEM) is used to observe and photograph the rubber phase particle size at a magnification of 20,000 times, and finally the average diameter of 50 rubber phase particles is calculated.

[0015] Preferably, the weight ratio of the POE elastomer to the SEBS is (5-15):(5-15). Further preferably, the weight ratio of the POE elastomer to the SEBS is (5-10):(10-15).

[0016] In one embodiment, the weight ratio of the POE elastomer to the SEBS is in the range of one or any two of 5:15, 8:15, 10:15, 10:10, 7.5:7.5, 15:5, 15:10, and 15:8.

[0017] The inventors found in actual experimental processes that the weight ratio of the POE elastomer and SEBS further affects the physical anchoring force between the material surface and the paint layer. When the above-mentioned specific weight ratio is adopted, the physical anchoring force between the material surface and the paint layer is better.

[0018] Preferably, the polypropylene resin has a melt flow rate of 10-60 g / 10 min at 230° C. and 2.16 kg according to ISO 1133-1 2022;

[0019] In one embodiment, the melt flow rate of the polypropylene resin is in the range of one or any two of 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 50 g / 10 min, 55 g / 10 min, and 60 g / 10 min.

[0020] Preferably, the POE elastomer is ethylene octene copolymer or ethylene butene copolymer.

[0021] Preferably, the mass percentage content of styrene in the SEBS is in the range of 10-70%.

[0022] Preferably, the melt flow rate of the POE elastomer according to ISO 1133-2022 at 190°C and 2.16kg is 2-10g / 10min, and the solution viscosity of the SEBS according to GB / T2794-2013 at a temperature of 25°C and a 20% toluene solution is 200-2000mPa·s; further preferably, the melt flow rate of the POE elastomer according to ISO 1133-2022 at 190°C and 2.16kg is 3-5g / 10min, and the solution viscosity of the SEBS according to GB / T2794-2013 at a temperature of 25°C and a 20% toluene solution is 1000-1500mPa·s.

[0023] In one embodiment, the melt flow rate of the POE elastomer at 190°C and 2.16 kg according to ISO 1133-2022 is 2 g / 10 min, 3 g / 10 min, 3.5 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, 10 g / 10 min or any two of the range values; the SEBS is according to GB / T2 794-2013 The solution viscosity at 25°C and 20% toluene solution is in the range of one or any two of 200, 250, 300, 350, 400, 450, 600, 800, 850, 900, 950, 980, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, and 2000 mPa·s.

[0024] Preferably, the average particle size of the talc powder is 2000-5000 mesh, and the particle size D50 is 3-8 μm.

[0025] In one embodiment, the average particle size of the talc powder is one of 2000 mesh, 2500 mesh, 3000 mesh, 3500 mesh, 4000 mesh, 4500 mesh, 5000 mesh or any two of the range values; the particle size D50 of the talc powder is one of 3μm, 4μm, 5μm, 6μm, 7μm, 8μm or any two of the range values.

[0026] Preferably, the antioxidant is at least one of hindered phenols and phosphites.

[0027] Optionally, the hindered phenol antioxidant includes at least one of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester, bis[β-(3,5-di-tert-butyl-4-hydroxy-phenylpropionyl)]hydrazine, and tetrakis[β-(3.5-di-tert-butyl, 4-hydroxyphenyl)propionate]pentaerythritol; the phosphite antioxidant includes at least one of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate, tetrakis(2,4-di-tert-butylphenol)-4,4-biphenyl diphosphite, and tris[2.4-di-tert-butylphenyl]phosphite.

[0028] In addition, the present invention provides a method for preparing the polypropylene composite material, comprising the following steps: mixing polypropylene resin, elastomer and antioxidant and adding them into an extruder for melting and dispersion, adding talcum powder into the extruder through a side feed port, extruding and granulating to obtain the polypropylene composite material.

[0029] Preferably, the twin-screw extruder is set at a temperature of 160-200° C. and a screw speed of 200-450 rpm.

[0030] Furthermore, the present invention provides the use of the polypropylene composite material in surface coating, wherein the polypropylene composite material is not flame treated before coating.

[0031] In one embodiment, the present invention provides the use of the polypropylene composite material in exterior parts that need to be painted, such as automobile bumpers, anti-friction strips, fenders, and wheel covers.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts a method of compounding a specifically selected POE elastomer and a hydrogenated styrene-butadiene-styrene triblock copolymer, SEBS has good rigidity, and the POE elastomer can form a paint penetration channel. The combination of the two is more conducive to the paint penetrating into the material surface to form a physical anchoring connection, so that the rigidity of the material surface and the paint permeability reach the best balance, thereby giving the material surface and the paint layer the best physical anchoring connection, and can pass the harsh high temperature and high pressure flushing paint adhesion test. DETAILED DESCRIPTION

[0033] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. 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 ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise specified, the experimental reagents and instruments designed for the implementation and comparative examples of the present invention are all commonly used ordinary reagents and instruments, which can be obtained from commercial channels. In the implementation and comparative examples, the experimental methods used are conventional methods unless otherwise specified; and unless otherwise specified, the raw materials used in parallel experiments are the same batch of raw materials.

[0034] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials:

[0035] Polypropylene resin-1: PP EP300M, melt flow rate 10 g / min (230°C / 2.16 Kg), CNOOC Shell;

[0036] Polypropylene resin-2: PP EP548R, melt flow rate 30g / 10min (230℃ / 2.16Kg), CNOOC Shell;

[0037] Polypropylene resin-3: PP K7760H, melt flow rate 60 g / min (230°C / 2.16 Kg), CNOOC Shell;

[0038] POE elastomer-1: POE 8452, melt flow rate 3g / 10min (190℃ / 2.16Kg), Dow Chemical;

[0039] POE elastomer-2: POE 7447, melt flow rate 5g / 10min (190℃ / 2.16Kg), Dow Chemical;

[0040] POE elastomer-3: POE 7256, melt flow rate 2.5g / 10min (190℃ / 2.16Kg), Dow Chemical;

[0041] POE elastomer-4: POE 8137, melt flow rate 13g / 10min (190℃ / 2.16Kg), Dow Chemical;

[0042] POE elastomer-5: POE 7367, melt flow rate 0.8 g / 10 min (190°C / 2.16 Kg), Dow Chemical;

[0043] POE elastomer-6: POE 8411, melt flow rate 18g / 10min (190℃ / 2.16Kg), Dow Chemical;

[0044] SEBS-1: ZL-Q5503, 20% toluene solution at 25°C with a viscosity of 1300 mPa·s, Zhongli Technology;

[0045] SEBS-2: SEBS 9557D, temperature 25°C, 20% toluene solution viscosity 1500 mPa·s, Lee Chang-jung, Taiwan, China;

[0046] SEBS-3: SEBS ZL-Q5537, 20% toluene solution at 25°C with a viscosity of 600 mPa·s, from Zhongli Technology;

[0047] SEBS-4: SEBS 7550, 20% toluene solution at 25°C with a viscosity of 1850 mPa·s, produced by Lee Chang-jung of Taiwan, China;

[0048] SEBS-5: SEBS ZL-S6552, 20% toluene solution at 25°C with a viscosity of 380 mPa·s, from Zhongli Technology;

[0049] SEBS-6: YH-503T, temperature 25°C, 10% toluene solution viscosity 2300mPa·s, Baling Petrochemical;

[0050] SBS: SBS ZL-H3591, 20% toluene solution at 25°C with a viscosity of 1950 mPa·s, Zhongli Technology;

[0051] Talc: AH-3000N1, average particle size 3000 mesh, particle size D50 5.5μm, Haicheng, Liaoning;

[0052] The antioxidant is a composite of a commercially available hindered phenol antioxidant 1010 and a commercially available phosphite antioxidant 168 in a mass ratio of 1:1.

[0053] The testing method for the rubber phase particle size of the elastomer ethylene / octene copolymer or SEBS is as follows: prepare the sample by ultrathin sectioning method under liquid nitrogen freezing state, control the sample thickness at 50 microns, dye the elastomer phase with ruthenium trichloride, and then use scanning transmission electron microscope (STEM) to observe and photograph the rubber phase particle size at 20,000 times magnification, and finally calculate the average value of the diameters of 50 rubber phase particles.

[0054] Examples 1-14 and Comparative Examples 1-8

[0055] The polypropylene composite material of the present invention has the following components as shown in Table 1. The preparation method of the polypropylene composite material comprises the following steps:

[0056] The polypropylene resin, elastomer and antioxidant are weighed according to weight and added to a high-speed mixer for 3-5 minutes, and then added to a twin-screw extruder with an aspect ratio of 48:1 for melting, mixing and dispersion. The talcum powder is added to the extruder through a side feed port at an aspect ratio of 36:1 through a metering scale. All materials are plasticized and uniformly extruded into granules through a twin-screw extruder. The twin-screw extruder is set at a temperature of 160-200°C and a screw speed of 200-450 rpm.

[0057] Performance Testing

[0058] (1) Testing method for rubber phase particle size

[0059] The testing method for the rubber phase particle size of the elastomer ethylene / octene copolymer or SEBS is as follows: prepare the sample by ultrathin sectioning method under liquid nitrogen freezing state, the sample thickness is 50 microns, the elastomer phase is stained with ruthenium trichloride, and then a scanning transmission electron microscope (STEM) is used to observe and photograph the rubber phase particle size at a magnification of 20,000 times, and finally the average diameter of 50 rubber phase particles is calculated.

[0060] (2) Paint Adhesion Test Method

[0061] 1. Sample preparation: Injection mold the plastic particles into a sample with a size of 100×100×3.0mm.

[0062] 2. Painting method: spray primer, topcoat and varnish in order, with the thickness of primer being 15μm, topcoat being 20μm and varnish being 25μm. After painting, dry in a 100℃ oven for 4 hours.

[0063] 3. Test conditions: Use 463 scratch tester to scratch the painted sample, scratch two straight lines at a 45° angle, then use 70bar / 60℃ high temperature and high pressure water to flush the intersection of the two scratches for 60s, and evaluate the paint adhesion level based on the paint shedding after flushing.

[0064] 4. High-pressure and high-temperature water-washing paint adhesion evaluation level:

[0065] It is divided into grades 0-3 according to the area and degree of paint peeling.

[0066] 1) Grade 0, no paint falling off points, excellent;

[0067] 2) Grade 1: The diameter of the paint peeling point is less than 0.5mm, which is good. It is divided into 1a / 1b / 1c according to the paint peeling area. In order of quality, 1a>1b>1c;

[0068] 3) Grade 2: The diameter of the paint peeling point is less than 1.0 mm. Generally, it is divided into 2a / 2b / 2c according to the paint peeling area. In order of quality, 2a>2b>2c;

[0069] 4) Grade 3: the diameter of the paint peeling point is greater than 1.0 mm, poor, and is subdivided into 3a / 3b / 3c according to the paint peeling area. In order of quality, 3a>3b>3c;

[0070] The results of the performance test are shown in Table 1.

[0071] Table 1

[0072]

[0073]

[0074] Table 2

[0075]

[0076] It can be seen from the above table that in the polypropylene composite materials prepared in Examples 1-14 of the present invention, the rubber phase particle size of the POE elastomer is 2-10 μm, and the rubber phase particle size of the SEBS is 50-300 nm. The rigidity and paint permeability of the prepared polypropylene composite materials achieve an optimal balance, and the adhesion grade is 2b and above, and can pass the harsh high temperature and high pressure water washing paint adhesion test.

[0077] By comparing Example 1, Examples 4-9, Comparative Examples 1-4, and Comparative Example 5, it can be seen that in the prepared polypropylene composite material, the rubber phase particle size of the POE elastomer is 4-6 μm, and the rubber phase particle size of the SEBS is 100-200 nm, that is, the melt flow rate of the POE elastomer at 190° C. and 2.16 kg according to ISO 1133-2022 is 3-5 g / 10 min, and the solution viscosity of the SEBS at a temperature of 25° C. and 20% toluene solution according to GB / T2794-2013 is 1000-1500 mPa·s, and the adhesion is better.

[0078] From the comparison between Example 1 and Examples 10-12, it can be seen that when the amount of polypropylene resin is 60-70 parts, the elastomer is 15-20 parts, the talc powder is 15-20 parts, and the antioxidant is 0.2-1 parts, the adhesion is better.

[0079] From the comparison between Example 1 and Comparative Examples 6-7, it can be seen that when the elastomer in the polypropylene composite material is only one of POE elastomer or SEBS, the adhesion is level 3, which is very poor.

[0080] From the comparison between Example 1 and Examples 13-14, it can be seen that when the weight ratio of the POE elastomer to SEBS is (5-10): (10-15), the adhesion is better.

[0081] From the comparison between Example 1 and Comparative Example 8, it can be seen that the elastomer in the polypropylene composite material is composed of POE elastomer and SEBS, but when the amount of the elastomer is too small, the adhesion is level 3, and the effect is very poor.

[0082] 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 composite material, characterized in that: The invention comprises the following components in parts by weight: 45-80 parts of polypropylene resin, 10-25 parts of elastomer, 10-25 parts of talc powder and 0.2-1 part of antioxidant; wherein the elastomer is composed of POE elastomer and SEBS; the rubber phase particle size of the POE elastomer in the polypropylene composite material is 2-10 μm, and the rubber phase particle size of the SEBS is 50-300 nm.

2. The polypropylene composite material according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 60-70 parts of polypropylene resin, 15-20 parts of elastomer, 15-20 parts of talc powder and 0.2-1 part of antioxidant.

3. The polypropylene composite material according to claim 1, characterized in that: In the polypropylene composite material, the rubber phase particle size of the POE elastomer is 4-6 μm, and the rubber phase particle size of the SEBS is 100-200 nm.

4. The polypropylene composite material according to claim 1, characterized in that: The weight ratio of the POE elastomer to the SEBS is (5-15):(5-15); preferably, the weight ratio of the POE elastomer to the SEBS is (5-10):(10-15).

5. The polypropylene composite material according to claim 1, characterized in that: The polypropylene resin has a melt flow rate of 10-60 g / 10 min at 230° C. and 2.16 kg according to ISO 1133-12022.

6. The polypropylene composite material according to claim 1, characterized in that: The melt flow rate of the POE elastomer is 2-10 g / 10 min at 190° C. and 2.16 kg according to ISO 1133-2022, and the solution viscosity of the SEBS is 200-2000 mPa·s at 25° C. and 20% toluene solution according to GB / T2794-2013.

7. The polypropylene composite material according to claim 1, characterized in that: The melt flow rate of the POE elastomer is 3-5 g / 10 min at 190° C. and 2.16 kg according to ISO 1133-2022, and the solution viscosity of the SEBS is 1000-1500 mPa·s at 25° C. and 20% toluene solution according to GB / T2794-2013.

8. The polypropylene composite material according to claim 1, characterized in that: The antioxidant is at least one of hindered phenols and phosphites.

9. A method for preparing a polypropylene composite material according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing polypropylene resin, elastomer and antioxidant and adding them into an extruder for melting and dispersion, adding talcum powder into the extruder through a side feeding port, extruding and granulating to obtain the polypropylene composite material.

10. Use of the polypropylene composite material according to any one of claims 1 to 8 in surface coating, characterized in that: The polypropylene composite material is not flame treated before coating.

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