Pp composite material as well as preparation method therefor and use thereof

Abstract

Disclosed in the present invention are a PP composite material as well as a preparation method therefor and the use thereof. The PP composite material comprises the following components in parts by weight: 40-60 parts of a PP resin, 10-20 parts of a POE resin, 10-30 parts of talcum powder, 1-4 parts of carbon nanotubes, 4-10 parts of carbon black, 0.5-1.5 parts of a dispersing agent and 0-4 parts of an auxiliary agent. The obtained material has good resistance stability while having good material fluidity, appearance flatness and impact toughness, and is therefore particularly suitable for forming large-scale exterior parts such as automobile bumpers and parts with high requirements on impact resistance.

Description

A PP composite material, preparation method and use Technical Field

[0001] The present invention belongs to the technical field of plastics, and in particular relates to a PP composite material, a preparation method and uses thereof. Background Art

[0002] With the advancement of technology, plastics have been widely used in various industries, especially PP resin has been used in the automotive field due to its excellent performance.

[0003] Currently, the application of PP composite materials in automotive exteriors requires surface painting. The existing technology uses PP composite materials for painting, which has a complicated process. In addition, traditional PP materials have poor resistance stability. Online spraying cannot conduct away the charge in time, resulting in the inability to achieve online spraying. Only offline spraying can be used, and the painting rate is low.

[0004] The introduction of carbon nanotubes and carbon black ensures resistance stability. However, conventional carbon nanotubes and carbon black alone cannot meet the other requirements of such large parts, preventing rapid painting and resulting in low painting efficiency. Therefore, this patent utilizes specific components and adjusts their weights to ensure resistance stability and fluidity, enabling the part to be sprayed inline with the vehicle body, while also improving painting efficiency. Summary of the Invention

[0005] The present invention provides a PP composite material that can be spray-coated with a vehicle body inline. The composite material comprises the following components, by weight: 40-60 parts PP resin, 10-20 parts POE resin, 10-30 parts talc, 1-4 parts carbon nanotubes, 4-10 parts carbon black, 0.5-1.5 parts dispersant, and 0-4 parts additive. The dispersant is a wax. The PP resin accounts for greater than 36.5% of the PP composite material. Specifically, the PP resin is one or more of homopolypropylene and copolymer polypropylene, and exhibits a melt index range of 60-120 g / 10 min under melt index test conditions of 230°C / 2.16 kg.

[0006] Specifically, under the melt index test conditions of 190° C. / 2.16 kg, the melt index of POE resin ranges from 5 to 15 g / 10 min.

[0007] The test is based on the ISO1133 standard.

[0008] Specifically, the auxiliary agent includes one or more of an oxidant, a nucleating agent or a lubricant.

[0009] The antioxidants include: one or more of phenols or hindered amines, or one or more of phosphites or sulfuric acid.

[0010] The nucleating agent is a carboxylic acid metal salt or an organic phosphate nucleating agent, specifically at least one of aluminum benzoate, aluminum tert-butylbenzoate, bis(p-tert-butylbenzoate)hydroxyaluminum, sodium benzoate, sodium β-naphthoate, hydroxyethylidene diphosphonic acid, or sodium hydroxyethylidene diphosphonate;

[0011] The lubricant is one of fluoride, fatty acid and its esters, fatty acid amide, metal soap, hydrocarbon or organosilicon compound, specifically at least one of zinc stearate, barium stearate, stearic acid monoglyceride, polyethylene, polypropylene, polystyrene or tristearin.

[0012] Specifically, the carbon nanotubes may be single-walled carbon nanotubes or multi-walled carbon nanotubes, with a carbon content greater than 95%.

[0013] Specifically, the weight ratio of carbon nanotubes to carbon black is 1:1.5-6.1.

[0014] Specifically, the carbon black has an oil absorption value of 130-190 cc / 100 g and a structure degree of 3-15 ml / (100 g*nm), preferably, a structure degree of 4.5-10 ml / (100 g*nm).

[0015] Test method: Take 0.5g of carbon black, pour an appropriate amount of dibutyl phthalate (hereinafter referred to as: DBP) into a burette, adjust the burette scale to zero, pour the carbon black onto a glass plate, drip DBP on the carbon black at a uniform speed, and stir and roll it continuously with a glass rod. When the mixture of carbon black and DBP appears in a characteristic shape (hard carbon black and pigment carbon black appear in thin strips, soft carbon black appears in small pieces, and there is no fine powder or granular carbon black), roll all the carbon black onto the glass rod, and no oil marks appear on the glass plate, which is the end point.

[0016] Oil absorption value = DBP consumption (in ml) ÷ carbon black mass in grams (0.5g in the above experiment) x 100. Structure formula: Oil absorption value ÷ carbon black particle size.

[0017] The present invention also provides a method for preparing a PP composite material, comprising:

[0018] After uniformly mixing 1-4 parts of carbon nanotubes with 0.5-1.5 parts of dispersant according to weight, the mixture is uniformly mixed with 40-60 parts of PP resin, 10-20 parts of POE resin, 10-30 parts of talc and additives, and placed at the front feed port of a twin-screw extruder. 4-10 parts of carbon black are placed at the side feed port of the twin-screw extruder for extrusion processing. Finished particles are obtained through extrusion, cooling and granulation. The temperature of each zone of the twin-screw extruder is 180-240°C, and the amount of additives used is 0.1-4 parts.

[0019] The addition of specific dispersants helps prevent the occurrence of crystal defects and unstable electrical conductivity in the material.

[0020] The present invention also provides the application of the above PP composite material in the field of surface painting of automobile parts, which has a good painting effect on the parts and can be sprayed online together with the car body, and has a good appearance.

[0021] The specific weight ratios of carbon nanotubes and carbon black in the present invention not only reduce the amount of carbon nanotubes used and improve the fluidity of the PP composite, resulting in a smoother, less defective surface finish for painted automotive parts, but also avoid the narrow processing window caused by the narrow permeability range of the material's resistance, often associated with carbon black alone. This ensures conductive stability, allowing for in-line painting of the finished part alongside the vehicle body, while also improving painting efficiency. Furthermore, a PP composite prepared by mixing PP with a melt index of 60-120 g / 10 min with POE with a melt index of 5-15 g / 10 min in a mass ratio of 2-6:1 exhibits excellent fluidity and strong impact toughness, making it suitable for use in automotive bumpers requiring high impact resistance.

[0022] The injection-molded parts of the present invention exhibit good fluidity, a smooth appearance, few defects, and excellent electrical resistance stability. They can be directly electrostatically sprayed like metal, enabling rapid painting. Furthermore, they can be directly applied to the vehicle body and painted simultaneously, improving production efficiency. While ensuring electrical resistance stability, the present invention also balances material fluidity and impact toughness, making it particularly suitable for molding large parts such as automotive bumpers and parts requiring high impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic diagram of surface crystal point defects of the PP composite material obtained in Example 1;

[0024] FIG2 is a schematic diagram of surface crystal point defects of the PP composite material obtained in Comparative Example 1. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] The types and models of PP resin, POE resin, talc, carbon nanotubes, carbon black, dispersant, and additives used in the following examples and comparative examples are as follows:

[0027] Polypropylene: PP-1, EP640V, commercially available, melt index 100 g / 10 min, 230 ° C / 2.16 kg;

[0028] PP-2, PP H9018, commercially available, melt index 50g / 10min, 230℃ / 2.16kg;

[0029] PP-3, M60T, commercially available, melt index 60g / 10min, 230℃ / 2.16kg;

[0030] Polyolefin elastomer: POE 8137, commercially available: melt index 13 g / 10 min, 190 ° C / 2.16 kg;

[0031] POE-2, POE DF740, commercially available, melt index 3g / 10min, 190℃ / 2.16kg;

[0032] POE-3, ENGAGE 8207, commercially available, melt index 5g / 10min, 190℃ / 2.16kg;

[0033] Talc: TYT-777A, commercially available;

[0034] Carbon nanotubes: XFM34, multi-walled carbon nanotubes;

[0035] Carbon black 1: VXC72, after grinding, oil absorption value 160cc / 100g, structure degree 10ml / (100g*nm);

[0036] Carbon black 2: Conductex 7067, oil absorption 140cc / 100g, structure 7ml / (100g*nm);

[0037] Carbon black 3: CB-38B, oil absorption value 135cc / 100g, structure degree 4.5ml / (100g*nm);

[0038] Dispersant: paraffin, TEGOMER, Yingchuang;

[0039] Nucleating agent: organic phosphate, NP-509, commercially available;

[0040] Lubricant: zinc stearate, GZ1042, commercially available;

[0041] Antioxidants: SONOX 1010 and SONOX 168, mixed in a ratio of 1:1 by mass, commercially available.

[0042] Preparation methods of embodiments and comparative examples

[0043] After uniformly mixing the carbon nanotubes and the dispersant according to the weight parts shown in Table 2, the mixture was uniformly mixed with the PP resin, the POE resin, the talc powder and the additives, and placed in the front feed port of a twin-screw extruder. The carbon black was placed in the side feed port of the twin-screw extruder for extrusion processing. The finished PP composite material particles were obtained through extrusion, cooling and granulation. The temperature of each zone of the twin-screw extruder was 180-240°C.

[0044] The following Examples 2-9 and Comparative Examples 1-8 can be prepared according to the component contents specified in Table 1 and referring to the above method to prepare the compositions.

[0045] Table 1. Amounts of components used in comparative examples and examples (unit: parts by weight)

[0046] Table 2. Amounts of components used in the examples (unit: parts by weight)

[0047] The PP composite materials prepared from the components described in the above examples and comparative examples were tested for surface resistance stability, melt index, and notched impact performance. Surface resistance was tested according to ASTM D257, measuring the difference between five points. The maximum and minimum values ​​were used to determine the range of resistance stability. Melt index was tested according to ISO 1133. Crystal points were counted within a 5 cm x 5 cm area using a Leica optical electron microscope. Notched impact testing was performed according to ISO 180.

[0048] Table 3 Test results of comparative examples

[0049] Table 4 Test results of the embodiment

[0050] Comparative Examples 1 and 2, containing only carbon nanotubes or carbon black, exhibit poor resistance stability, fluctuating between five resistance levels, E6-E10 and E8-E12. Furthermore, the composites containing only carbon nanotubes or carbon black exhibit poor fluidity. Compared to Example 1, the composites containing carbon nanotubes and carbon black exhibit strong resistance stability, with virtually no fluctuations. Furthermore, the resistance stability of Examples 1, 3, and 4 is superior to that of Example 5, demonstrating that resistance stability is strong when the weight ratio of carbon nanotubes to carbon black is 1:1.5-6.1. The composite materials obtained in Examples 1-9 exhibit a melt index of 30-40 g / 10 min at 230°C / 2.16 kg, meeting the standard requirement of 20-50 g / 10 min (230°C / 2.16 kg) for rapid spraying.

[0051] In Comparative Examples 3 and 4, the melt index of PP is less than 60, and the melt index of POE is less than 5. Compared with Example 1, the impact strength is reduced and the resistance stability is also poor. In Comparative Example 5, when the dispersant is less than 0.5, the resistance stability is E6-E10 and the notched impact is 10KJ / m 2, low resistance stability, and low impact resistance. Please refer to Figures 1 and 2, which are schematic diagrams of crystal points captured at 50x magnification using an optical electron microscope on the surfaces of the PP materials obtained in Example 1 and Comparative Example 1, respectively. The crystal points on the surface of Example 1 are fine, while those in Comparative Example 1 are coarse. Because Example 1 is a composite of carbon nanotubes and carbon black, the components have good fluidity and fine crystal points. Comparative Example 1 contains only carbon nanotubes, which have poor fluidity and larger crystal points.

[0052] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A PP composite material, characterized in that: The invention comprises the following components in parts by weight: 40-60 parts of PP resin, 10-20 parts of POE resin, 10-30 parts of talc, 1-4 parts of carbon nanotubes, 4-10 parts of carbon black, 0.5-1.5 parts of dispersant and 0-4 parts of auxiliary agent, wherein the dispersant is wax.

2. The composite material according to claim 1, characterized in that Additives include: One or more of an antioxidant, a nucleating agent or a lubricant.

3. The composite material according to claim 2, characterized in that The antioxidant includes: one or more of phenols or hindered amines, or one or more of phosphites or sulfuric acids, the nucleating agent is a carboxylic acid metal salt or an organic phosphate nucleating agent, and the lubricant is one of fluoride, fatty acid and its esters, fatty acid amide, metal soap, hydrocarbon or organosilicon compound.

4. The composite material according to claim 1, characterized in that PP resin is one or more of homopolymer polypropylene and copolymer polypropylene, and the melt index range is >60g / 10min.

5. The composite material according to claim 1, characterized in that The melt index range of POE resin is ≥5g / 10min.

6. The composite material according to claim 1, characterized in that The weight ratio of carbon nanotubes to carbon black is 1:1.5-6.

1.

7. The composite material according to claim 1, characterized in that The carbon nanotubes may be single-walled carbon nanotubes or multi-walled carbon nanotubes.

8. The composite material according to claim 1, characterized in that The oil absorption value of carbon black is 130-190cc / 100g, and the structural degree is 3-15ml / (100g*nm).

9. A method for preparing a PP composite material, characterized in that: include: After uniformly mixing 1-4 parts of carbon nanotubes and 0.5-1.5 parts of dispersant according to weight, the mixture is uniformly mixed with 40-60 parts of PP resin, 10-20 parts of POE resin, 10-30 parts of talcum powder and 0-4 parts of additives, and placed at the front feed port of a twin-screw extruder. 4-10 parts of carbon black by weight are placed at the side feed port of the twin-screw extruder for extrusion processing. Finished particles are obtained through extrusion, cooling and granulation, wherein the temperature of each zone of the barrel of the twin-screw extruder is 180-240°C.

10. The PP composite material according to claim 1 is used in the field of surface painting of automobile parts.

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