A polypropylene composite material and its preparation method and application

Abstract

The present invention relates to a polypropylene composite material and a preparation method and application thereof, the components of which include polypropylene, glass fiber, olefin block copolymer OBC, maleic anhydride grafted polyethylene, lubricant, and antioxidant. The polypropylene composite material of the present invention has good touch, high chemical resistance and good low-temperature mechanical properties.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials, and particularly relates to a polypropylene composite material and a preparation method and application thereof. Background Art

[0002] As the general-purpose polymer material with the lowest density, polypropylene is widely used in the automotive, home appliance and other industries. However, the use of traditional PP materials in appearance parts is limited by their high gloss, poor scratch resistance and strong plastic feel. In response to this, in recent years, many patents have reported technical solutions for good-touch polypropylene materials. By filling a large amount of glass fiber and elastomer in polypropylene, the material has the characteristics of soft touch, scratch resistance, and low gloss. However, good-touch glass fiber reinforced polypropylene contains a large amount of elastomer (especially POE), which leads to poor chemical resistance, limiting its scope of use; at the same time, conventional good-touch glass fiber reinforced polypropylene is not tough enough under low temperature conditions. If it is used in dashboards, pillars, door panels and other parts that require low-temperature explosion or low-temperature side protrusion, there are great safety hazards. Summary of the invention

[0003] In view of the defects of the prior art, the technical problem to be solved by the present invention is to provide a chemical-resistant, good-touch polypropylene composite material and a preparation method and application thereof.

[0004] The polypropylene composite material of the present invention comprises the following components in parts by weight:

[0005] Polypropylene 25-60 parts;

[0006] Glass fiber 20-30 parts;

[0007] 5-12 parts of tetrapod-shaped zinc oxide whiskers;

[0008] Olefin block copolymer OBC 25-40 parts;

[0009] 1-6 parts of maleic anhydride grafted polyethylene;

[0010] The average length of the needle-shaped part of the four-needle zinc oxide whisker is 50-150 μm, and the testing method is to observe using an electron microscope.

[0011] The melt index of the polypropylene at 230° C. / 2.16 kg is 0.5-100 g / 10 min, and the test standard is ISO1133-1:2011.

[0012] The average length of the needle-shaped part of the four-needle zinc oxide whisker can be selected as 60-80 μm, 120-140 μm, 140-150 μm, etc.

[0013] Preferably, the average length of the needle-shaped parts of the four-needle zinc oxide whiskers is 70-130 μm.

[0014] Preferably, the density of the olefin block copolymer OBC is 0.866-0.887 g.cm -3 .

[0015] Further, preferably, the density of the olefin block copolymer OBC is 0.870-0.880 g.cm -3 .

[0016] The density of OBC is determined by the ratio of the "hard segment" composed of the polyethylene crystal region and the amorphous "soft segment" of the ethylene / octene copolymer. The higher the density, the higher the ratio of the "hard segment" and the poorer the touch; the lower the density, the higher the ratio of the "soft segment" and the poorer the chemical resistance. The optimal density range ensures good chemical resistance and touch performance.

[0017] The grafting rate of the maleic anhydride grafted polyethylene is 0.3%-2.0%, and the testing method is acid-base titration method.

[0018] Preferably, the components further include 0-1 part of lubricant and 0.1-1 part of antioxidant.

[0019] Preferably, the lubricant is one or more of fatty acid zinc stearate, stearic acid amide, N,N,-ethylene bisstearamide, oleic acid amide, erucic acid amide, oxidized polyethylene wax lubricant, and the like.

[0020] The antioxidant is one or more of phenols, amines, phosphites and semi-hindered phenols.

[0021] Preferably, by weight, the components include:

[0022] Polypropylene 40-50 parts;

[0023] Glass fiber 23-28 parts;

[0024] 7-10 parts of tetrapod-shaped zinc oxide whiskers;

[0025] Olefin block copolymer OBC 30-35 parts;

[0026] 2-5 parts of maleic anhydride grafted polyethylene.

[0027] A method for preparing the polypropylene composite material of the present invention comprises:

[0028] The components are weighed according to weight fraction, mixed, extruded and granulated to obtain a polypropylene composite material.

[0029] Furthermore, each component is weighed according to weight, polypropylene, olefin block copolymer OBC, maleic anhydride grafted polyethylene, lubricant and antioxidant are mixed and fed into a twin-screw extruder from a main feeding port, four-needle zinc oxide whiskers are fed into the extruder from a side feeding port of zones 4-6 of the extruder, and glass fibers are fed into the extruder from a side feeding port of zones 7-9 of the extruder, and the polypropylene composite material is obtained through melt extrusion, strip drawing, cooling and granulation.

[0030] Preferably, the aspect ratio of the twin-screw extruder is 48:1-72:1, the extrusion temperature is 200-240°C, the screw speed is 300-1000rpm, and the vacuum degree is ≤-0.08bar.

[0031] The polypropylene composite material of the present invention is used in automobile interior parts, such as instrument panels, pillars, door panels, etc.

[0032] The present invention uses an olefin block copolymer OBC, which consists of two segments: a "hard segment" composed of a polyethylene crystalline region and an amorphous "soft segment" of ethylene / octene copolymer. The polyethylene crystalline region can effectively hinder the penetration of chemicals and greatly improve the chemical resistance of the system. At the same time, the four-needle zinc oxide whiskers in the system play a supporting role and can delay the swelling of the substrate by the chemicals in all directions. Through the synergy of the two, the problem of poor chemical resistance of good-tactile materials is effectively solved.

[0033] The present invention preferably uses maleic anhydride grafted polyethylene as a compatibilizer for polypropylene, OBC and glass fiber in the system, so that the "hard segment" (PE crystal region) of the glass fiber and OBC is strongly linked by chemical bonds, and the "soft segment" of OBC is tightly attached to the glass fiber, thereby ensuring the brittleness of the material at -30°C. Through the synergistic effect of OBC and maleic anhydride grafted polyethylene, the composite material has good low-temperature toughness characteristics.

[0034] Beneficial Effects

[0035] The polypropylene composite material of the invention has good touch, high chemical resistance and good low-temperature mechanical properties. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0037] 1. Source of raw materials

[0038] Polypropylene-1: PP 7935, melt index 60g / 10min, 230℃ / 2.16KG, manufacturer: Exxon;

[0039] Polypropylene-2: PP 548R, melt index 28g / 10min, 230℃ / 2.16KG, manufacturer: COSCO SHIPPING;

[0040] Glass fiber: ECS13-4.5-508A Manufacturer: China Jushi;

[0041] Four-needle zinc oxide whisker-1: The average length of the needle-shaped part is 70 μm, manufacturer: Hangzhou Jikang New Materials Co., Ltd.

[0042] Four-needle zinc oxide whisker-2: average length of the needle-shaped part is 130μm, manufacturer: Hangzhou Jikang New Materials Co., Ltd.

[0043] Four-needle zinc oxide whisker-3: average length of the needle-shaped part is 50μm, manufacturer: Hangzhou Jikang New Materials Co., Ltd.

[0044] Four-needle zinc oxide whisker-4: average length of the needle-shaped part is 150μm, manufacturer: Hangzhou Jikang New Materials Co., Ltd.

[0045] Four-needle zinc oxide whisker-5: average length of the needle-shaped part is 20 μm, manufacturer: Hangzhou Jikang New Materials Co., Ltd.

[0046] Tetrapod-shaped zinc oxide whisker-6: average length of the needle-shaped part is 180 μm, manufacturer: Hangzhou Jikang New Materials Co., Ltd. Zinc oxide-7: nanosheet zinc oxide, 50 ± 10 nm, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0047] Olefin block copolymer OBC-1: DOW 9500, density 0.877, manufacturer: Dow;

[0048] Olefin block copolymer OBC-2: DOW 9107, density 0.866, manufacturer: Dow;

[0049] Olefin block copolymer OBC-3: DOW 9530, density 0.887, manufacturer: Dow;

[0050] POE: 7447, Manufacturer: Dow;

[0051] Maleic anhydride grafted polyethylene-1: CMG5904, manufacturer: Jiayirong, grafting rate 0.7%;

[0052] Maleic anhydride grafted polyethylene-2: OREVACOE825, manufacturer: SK, grafting rate 1.1%;

[0053] Maleic anhydride grafted polypropylene, CMG9801, manufacturer: Jiayirong, grafting rate 0.7%;

[0054] Lubricant: GZ1042, manufacturer: Jiangxi Hongyuan;

[0055] Antioxidant: Mix the following two antioxidants in a ratio of 1:1:

[0056] Hindered phenol antioxidant, brand: 1010, manufacturer: Yixing Angel Synthetic Chemical;

[0057] Phosphite antioxidant, brand: 168, manufacturer: Yixing Angel Synthetic Chemical; the lubricant and antioxidant used in the parallel examples and comparative examples are the same commercially available products.

[0058] 2. Preparation methods of embodiments and comparative examples

[0059] Weigh each component by weight, mix polypropylene, olefin block copolymer OBC, maleic anhydride grafted polyethylene, lubricant and antioxidant, and feed the mixture into a twin-screw extruder from a main feed port, feed four-needle zinc oxide whiskers into the extruder from a side feed port of zones 4-6 of the extruder, and feed glass fibers into the extruder from a side feed port of zones 7-9 of the extruder, and perform melt extrusion, strip drawing, cooling and granulation to obtain a polypropylene composite material; wherein the twin-screw extruder has an aspect ratio of 48:1-72:1, an extrusion temperature of 200-240°C, a screw speed of 300-1000rpm, and a vacuum degree of ≤-0.08bar.

[0060] 3. Test standards and methods

[0061] (1) Touch evaluation:

[0062] The samples were injection molded into Japanese 534# leather grain plates under the same injection molding conditions, and then placed at room temperature for 24 hours and scored by 5 judges. The subjective test method was: press the sample with the index finger at an angle of 30°, control the pressure so that the contact area is 1 / 3 of the projection area of ​​the first knuckle, and swipe across 100mm at a speed of 10mm / s, and rate according to the table below.

[0063] Touch level Level Description 1 No rebound, strong hardness 2 No rebound but no obvious hardness 3 Slight rebound 4 There is a noticeable rebound feeling 5 Feel the comfortable rebound touch

[0064] (2) Gasoline resistance evaluation:

[0065] Refer to standard Q / JLY J7110281D-2016 5.11, use a cloth soaked in gasoline to wipe the surface of the 100*100*2mm sample 10 times, place it vertically in an indoor environment at (23±2)℃ for 1 hour, then check the surface condition of the sample, and then place it in a damp heat test box at a temperature of (90±2)℃ for 1 hour, then check the appearance of the sample.

[0066] Appearance grade Level Description 1 Swelling, deformation, whitening 2 Severe oil spots 3 Obvious oil spots 4 Slight oil stain 5 No change in appearance

[0067] Note: Gasoline resistance appearance level, level 1 is the worst and level 5 is the best.

[0068] (3) Low temperature Izod notch impact test: Test standard ISO 180-2000, test condition -30℃, specimen size:

[0069] 4*10*80mm, notch depth 2mm.

[0070] (4) Flexural modulus: Test standard ISO 178-2010, test conditions 23°C, 2 mm / min, specimen size:

[0071] 4*10*80mm.

[0072] Table 1 Proportions of the embodiments (parts by weight)

[0073]

[0074]

[0075] Table 2 Comparative Example Proportions (parts by weight)

[0076]

[0077]

[0078] It can be seen from the examples that the polypropylene composite material of the present invention has a touch grade of 4 or above, a gasoline resistance grade of 4 or above, and a low-temperature Izod notched impact of 6-7.3 KJ / m 2 The flexural modulus is 2925-3540MPa, and it has good touch, high chemical resistance and good low-temperature mechanical properties.

[0079] The size of the four-needle zinc oxide whiskers added in Comparative Examples 1 and 2 is too short or too long. If it is too short, it cannot play a supporting role. If it is too long, the whiskers are easy to agglomerate, and the gasoline resistance effect is poor. The four-needle zinc oxide whiskers that are too short or too long in the system have limited support for the substrate, there is rebound but not enough support, the rebound comfort is slightly poor, and the touch evaluation is level 4;

[0080] In Comparative Example 3, maleic anhydride grafted polypropylene was used as a compatibilizer, which failed to achieve the effect of connecting glass fiber and OBC, OBC could not be coated on the glass fiber, and the low-temperature toughness of the system was poor;

[0081] Comparative Example 4 has no OBC, and the system has poor touch and extremely poor toughness;

[0082] Comparative Example 5 has no four-needle zinc oxide whiskers, and the chemical resistance of the system is poor; the system lacks the support of the four-needle zinc oxide whiskers, there is rebound but not enough support, the rebound comfort is slightly poor, and the touch evaluation is level 4;

[0083] Comparative Example 6 has no glass fiber and has a good touch, but the material is not rigid enough and is too soft to be used as a conventional material; meanwhile, it has poor gasoline resistance;

[0084] In Comparative Example 7, the content of tetrapod-shaped zinc oxide whiskers is too high and unevenly dispersed in the system, resulting in a small content of whiskers in some local areas, which are easily corroded by chemicals, resulting in poor chemical resistance.

Claims

1. A polypropylene composite material, characterized in that: By weight, the components include: The average length of the needle-shaped part of the four-needle zinc oxide whisker is 50-150 μm; the density of the olefin block copolymer OBC is 0.866-0.887 g.cm -3 .

2. The polypropylene composite material according to claim 1, characterized in that: The average length of the needle-shaped part of the four-needle zinc oxide whisker is 70-130 μm.

3. The polypropylene composite material according to claim 1, characterized in that: The components also include 0-1 part of lubricant and 0.1-1 part of antioxidant.

4. The polypropylene composite material according to claim 3, characterized in that: The lubricant is one of fatty acid zinc stearate, stearic acid amide, N,N,-ethylene bis stearamide, oleic acid amide, erucic acid amide, and oxidized polyethylene wax lubricant.

5. The polypropylene composite material according to claim 3, characterized in that: The antioxidant is one or more of phenolic, amine and phosphite antioxidants.

6. The polypropylene composite material according to claim 1, characterized in that: By weight, the components include:

7. A method for preparing the polypropylene composite material according to claim 1, comprising: The components are weighed according to weight, mixed, extruded and granulated to obtain a polypropylene composite material.

8. Use of the polypropylene composite material according to claim 1 in automobile interior parts.

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