WO2019042053A1 - Polypropylene composition and preparation method therefor - Google Patents

Abstract

Disclosed is a polypropylene composition, comprising: 60-85 parts by weight of polypropylene resin, 5-10 parts by weight of high-density polyethylene resin, 5-20 parts by weight of a POE complex formulation flexibilizer, 1-5 parts by weight of graphene, and 3-5 parts by weight of a surface modifier. The POE complex formulation flexibilizer adopted by the present invention maintains the good impact performance of a material while increasing the chemical corrosion-resistant performance thereof; the added surface modifier can reduce the erosion of chemicals to the surface of the material; the added graphene not only increases the intensity of the material, but also has an inhibition effect on chemical corrosion, and moreover, the added graphene enables the material to have a unique metal luster and can conceal defects such as fiddle back figures of an injection molding product. The synergism of the POE complex formulation flexibilizer, the surface modifier, and the graphene makes the polypropylene material composition have excellent chemical-resistant performance, maintain good rigid-tough balance, have good appearance, and be capable of being applied to interior and exterior decoration products of an automobile.

Description

Polypropylene composition and preparation method thereof Technical field

The present invention relates to polymer materials and techniques, and more particularly to a polypropylene composition and a method of preparing the same.

Background technique

Polypropylene (PP) is a general-purpose plastic with wide source, low density and easy processing. Various filling, reinforcing and toughening PP have been widely used in the automotive industry, such as engine periphery, interior and exterior. component. For safety and comfort, automotive PP has high requirements for toughness and impact resistance. In addition, auto parts are in a complex chemical environment and may be whitish, discolored or swollen by gasoline, oil, cosmetics, sweat, detergent, etc. In order to meet the requirements of safety and comfort and a good customer experience, many OEMs began to demand the chemical resistance of automotive PP.

With the development of the automotive industry, consumers are increasingly demanding the special aesthetic effects of automotive materials. In order to avoid the large amount of environmental pollutants generated during paint spraying, good-looking spray-free PP products have emerged. Good-looking, spray-free automotive PP products require no pre-treatment and can be assembled directly by direct injection molding. It eliminates the need for post-treatment after the spraying process, saves energy and high efficiency, and further reduces the production cost of parts. Therefore, there is still a need in the art to develop a good appearance, chemical resistant polypropylene composite material, which can be used in various application scenarios of automobiles.

Patent document CN104987595A adopts the addition of polyurethane elastomer in PP to improve the wear resistance and oil resistance of the material, and the addition of tetrafluoroethylene-hexafluoropropylene copolymer to improve the high temperature resistance and oil resistance. However, the production of the material requires multiple extrusion granulation and mixing, and the complicated steps are not conducive to large-scale production, and the material is mainly used for cables, and the use scene is single. The patent document CN106243484A uses a macromolecular silane or a fluoropolymer blended with PP to modify the PP composition to resist corrosion of chemicals such as oil and coolant at high temperatures. However, this material is mainly used in the periphery of the engine, and the use scene is single, and there is no further concern for improving mechanical properties and appearance. Patent document CN105602103A uses silane coupling agent modified graphene as a functional filler to impart antistatic properties to PP materials, as well as more excellent mechanical properties. However, this invention does not optimize the chemical resistance of the material.

Summary of the invention

The object of the present invention is to overcome the defects of material processing in the prior art, single use scenario, insufficient comprehensive performance, poor appearance, and the like, and provides a simple production process, good appearance, excellent chemical corrosion resistance, and good toughness balance performance. A polypropylene composition with a large number of application scenarios.

Another object of the invention is to provide a process for the preparation of the polypropylene composition.

The invention is achieved by the following technical solutions:

The polypropylene composition, by weight, comprises the following components:

Polypropylene resin 60 to 85 parts;

High density polyethylene resin 5 to 10 parts;

POE type compounding toughening agent 5 to 20 parts;

Graphene 1 to 5 parts;

Surface modifier 3 to 5 parts.

The polypropylene resin is selected from one or more of a homopolypropylene resin or a copolymerized polypropylene resin, and has a density ranging from 0.894 to 0.914 g/cm ³ , and a melt at 190 ° C and a load of 2.16 Kg. The mass flow rate is from 1 to 100 g/10 min.

The high-density polyethylene resin is an extrusion grade high-density polyethylene having a density of 0.948 to 0.958 g/cm ³ and a melt mass flow rate of 5 to 10 g/10 min at 190 ° C under a load of 2.16 kg.

The POE type compounding toughening agent is a compound of one or more of the random copolymerized POE and one or several of the block copolymerized POE, and the random copolymerized POE: block copolymerized POE is 1 3 to 3:1, preferably 1:2 to 2:1, having a density of 0.857 to 0.897 g/cm ³ , and a melt mass flow rate of 0.5 to 13 g/10 min at 190 ° C under a load of 2.16 kg.

The random copolymerized POE is selected from one or more of POE 8200, POE 8137, POE 8677, POE 7447, POE 7467; the block copolymerized POE is selected from one of POE 5535, POE 9107 or Several.

Random copolymerized POE has good toughening effect on PP, but its chemical resistance is poor. Block copolymerized POE has better chemical resistance, but the toughening effect on PP is not as good as random copolymerized POE. Therefore, the present invention selects the random POE and the block POE to be compounded in different ratios to achieve the purpose of the PP composition having both strong impact properties and chemical resistance.

The graphene is selected from one or more of mechanically exfoliated graphene and chemically modified graphene, and the sheet layer is 1 to 5 layers, the size is 0.1 to 20 μm, and the bulk density is 0.01 to 0.1 g/cm ^{3 .} . The mechanically exfoliated graphene is selected from KNG-G5; the chemically modified graphene is selected from the group consisting of TRGO. The chemically modified graphene is self-made by a thermal expansion method and is named TRGO.

The surface modifier is selected from the group consisting of a fluorine-containing resin perfluoropolyether oil having a molecular weight of ≥800,000, a polytetrafluoroethylene having a molecular weight of ≥800,000, a tetrafluoroethylene-hexafluoropropylene copolymer having a molecular weight of ≥800,000, and a density of One or more of 0.9 to 2.0 g/cm ³ of fluorine-modified polysiloxane; wherein, the addition of a fluorine-modified polysiloxane having a density of 0.9 to 2.0 g/cm ³ , a polypropylene composition It has the best chemical resistance.

The fluororesin perfluoropolyether oil having a molecular weight of ≥800,000 is selected from JC2000; the polytetrafluoroethylene having a molecular weight of ≥800,000 is selected from one or more of PTFE micropowders KTL-450 and F-201. The tetrafluoroethylene-hexafluoropropylene copolymer having a molecular weight of ≥800,000 is selected from NP-40; the fluorine-modified polysiloxane having a density of 0.9 to 2.0 g/cm ³ is selected from the group consisting of AF-600 and MOK-2027. One or several of HY-F-101.

The polypropylene composition further comprises 0 to 2 parts of a pigment selected from one or more of carbon black M717 or black masterbatch PE2772.

The polypropylene composition further comprises 0 to 2 parts of an auxiliary agent selected from one or more of an antioxidant and a light stabilizer.

The antioxidant is a hindered phenol and a phosphite antioxidant selected from one or more of 1010, 1076, 3114, 168, and PEP-36.

The light stabilizer is a hindered amine light stabilizer selected from one or more of UV-3808PP5, LA-402XP, and LA-402AF.

The preparation method of the polypropylene composition comprises the following steps:

a) polypropylene resin, high-density polyethylene resin, POE compound toughening agent, surface modifier, graphene, pigment and auxiliary agent are put into a high-speed mixer and mixed uniformly;

b) Adding to a twin-screw extruder, melt-kneading, and extrusion granulation to obtain a polypropylene composition.

Among them, the melt kneading temperature is 170 to 220 ° C, and the screw rotation speed is 350 to 450 rpm.

The properties of the polypropylene composition: having a special luster similar to metal, having a good appearance, and the workpiece obtained by injection molding has no defects such as tiger skin grain; soaking in gasoline for 24 hours under conditions of 23 ° C and 50% relative humidity After that, the oil absorption rate is less than 14%, and the tensile strength attenuation rate is less than 33%; a certain amount of chemicals drip on the sample, and after being placed at 23 ° C, 50% relative humidity for 24 hours, the appearance does not change significantly. The value of the notched impact strength + the value of the flexural modulus is 10 > 125, 60 kJ / m ² > notched impact strength > 30 kJ / m ² , 1100 MPa > flexural modulus > 800 MPa, which meets the requirements.

The invention has the following beneficial effects:

The invention adopts a POE type compounding toughening agent, which can make the PP composition have good impact performance and chemical resistance at the same time, and the effect cannot be achieved by using random copolymerized POE or block copolymerized POE alone. The added surface modifier can be enriched on the surface of the material, which reduces the corrosion of the material on the surface of the material; the addition of graphene not only increases the flexural modulus of the material, but also has a nano-barrier effect on the chemical, while making the material have a similar metal. Gloss, injection molded parts without defects such as tiger skin. The synergistic effect of the three materials allows the polypropylene material composition to have excellent chemical resistance, maintain a good toughness balance, and have a good appearance. Therefore, the good appearance chemical resistant polypropylene composition provided by the invention can be used in various automotive application scenarios such as automobile engine periphery, automobile interior, automobile exterior and the like. The invention can save the process of spraying paint and the like, and has the characteristics of simple production process, low cost, and reduction of environmental pollution.

Detailed ways

The present invention will be further described by the following specific embodiments. The following embodiments are illustrative of the embodiments of the invention, but the embodiments of the invention are not limited by the following examples.

The raw materials used in the examples and comparative experiments were the following raw materials, but were not limited to the following raw materials:

Polypropylene resin: PP BX3920, available from SK, Korea, having a density of 0.899 g/cm ³ and a melt mass flow rate of 85 g/10 min at 230 ° C under a load of 2.16 kg.

High-density polyethylene: HDPE DMDA8008, purchased from Dushanzi Petrochemical, density of 0.956g/cm ³ , at 190 ° C, 2.16Kg load, its melt mass flow rate is 7g/10min;

Random copolymerized POE: POE 7447, purchased from Dow, density of 0.865g / cm ³ ; at 190 ° C, 2.16Kg load, its melt mass flow rate is 5g/10min;

Block copolymerized POE: POE 5535, density of 0.877g / cm ³ , at 190 ° C, 2.16Kg load, the melt mass flow rate of 1g/10min;

Mechanically exfoliated graphene: KNG-G5 graphite powder, purchased from Xiamen Kaina Graphene Co., Ltd., the layer is 1-3 layers, the size is 5-10 microns; the bulk density is 0.01-0.1g/cm ³ ;

Fluorinated resin perfluoropolyether oil with molecular weight ≥800,000: JC2000, purchased from Shanghai Aiken Chemical Co., Ltd.;

Polytetrafluoroethylene with a molecular weight of ≥800,000: F-201, purchased from Daikin Fluorine;

Tetrafluoroethylene-hexafluoropropylene copolymer with molecular weight ≥800,000: NP-40, purchased from Daikin Fluorine;

Fluorine-modified polysiloxane having a density of 0.9 to 2.0 g/cm ³ : AF-600, purchased from Zhejiang Jiahua Jinghua Co., Ltd., with a density of 0.97-1.25 g/cm ³ ;

Fluorine-modified polysiloxane having a density of 0.9 to 2.0 g/cm ³ : MOK-2027, purchased from Merck Chemical, Germany, density 1.09 to 1.13 g/cm ³ ; carbon black: M717, purchased from Cabot;

Antioxidant 1010: purchased from BASF;

Antioxidant 168: purchased from BASF;

Light stabilizer UV-3808PP5: purchased from cyano;

Examples 1-14 and Comparative Examples 1-5:

Preparation method of polypropylene composition:

According to the formulas of Tables 1-3, the components are put into a high-speed mixer and mixed uniformly, and then added to a twin-screw extruder for melt-kneading. The melt-kneading temperature is 170-220 ° C, and the screw rotation speed is 350-450 rpm. The pellet was extruded and granulated to obtain a polypropylene composition. The mechanical performance test results are shown in Table 4; the chemical resistance test results are shown in Table 5.

Various performance evaluation methods:

(1) Chemical resistance appearance test: After the injection molding the swatch sample was adjusted in a standard environment (23 ° C, 50% relative humidity) for 24 hours, 0.1 mL of the chemical was dropped on the surface, and allowed to stand at 23 ° C for 24 hours. Gently wipe with gauze, rinse with deionized water if necessary, remove residual chemicals from the surface of the swatch, and observe changes in the appearance of the swatch surface. According to the degree of corrosion of the appearance, the 2nd, 1.5th, 1st, 0.5th, and 0th grades are sequentially set, and the swatches after the Corrosion show the foaming swelling, severe whitening, slight whitening, and slight imprinting. Observed), no significant changes. Through blind testing by multiple professionals, the average value is taken as the final chemical corrosion resistance grade. The chemicals used in the chemical-resistant appearance test include Nivea sunscreen, LLC antifreeze, 95# gasoline, WWF washing liquid, and oil 5W-30.

(2) Oil absorption rate test: After the ISO mechanical spline after injection molding is adjusted in the standard environment (23 ° C, 50% relative humidity) for 24 h, the sample mass M _{0 is} weighed, soaked in an appropriate amount of gasoline, and static at 23 ° C. After 24 h, the mechanical spline was taken out to remove the significant oil droplets on the surface, and then adjusted in a standard environment (23 ° C, 50% relative humidity) for 30 min, and the sample mass M _{i was} weighed. The oil absorption rate is calculated according to formula 1-1:

(3) Tensile strength decay rate test: According to the EN50342-5 standard, the ISO mechanical splines after injection molding were adjusted in a standard environment (23 ° C, 50% relative humidity) for 24 h, and then tested in two groups. The first set tested the tensile strength K _{0 of the} sample before oil absorption. The second group was immersed in gasoline, allowed to stand at 23 ° C for 24 h, and the mechanical spline was taken out to remove the significant oil droplets on the surface, and then adjusted in a standard environment (23 ° C, 50% relative humidity) for 30 min, and the sample was tested for oil absorption. Tensile strength K _i . Tensile strength decay rate is calculated according to formula 1-2

Where K ₀ : performance test value before oil absorption; K _i : performance test value after oil absorption.

(4) Mechanical property test: After the injection, the ISO mechanical spline was adjusted in the standard environment (23 ° C, 50% relative humidity) for 24 h, and the tensile strength, flexural strength, flexural modulus and notched impact strength of the sample were tested.

Tensile strength is performed in accordance with ISO 527.

The bending strength and flexural modulus were performed in accordance with the ISO178 standard.

The notched impact strength is performed in accordance with the ISO 180 standard.

Table 1: Improved formulation examples of toughening agent (parts by weight)

Table 2: Improved formulation of surface modifiers (parts by weight)

Table 3: Comparative Example (parts by weight)

Table 4: Performance test results of the polypropylene compositions of the examples and comparative examples

Table 5: Chemical resistance appearance test results of the polypropylene compositions of the examples and comparative examples

The value of the notched impact strength + the value of the flexural modulus is 10 > 125, 60 kJ / m ² > notched impact strength > 30 kJ / m ² , 1100 MPa > flexural modulus > 800 MPa, which meets the requirements.

The comparison of the mechanical properties and chemical resistance test results of Examples 1-14 and Comparative Examples 1-5 shows that the impact ratio of the polypropylene copolymer is excellent when the compound ratio of the random copolymerized POE to the block copolymerized POE is 4:1. However, the chemical resistance is general; when the compounding ratio is 1:4, the impact properties of the polypropylene material are generally good, and the chemical resistance is excellent; when the compounding ratio is from 3:1 to 1:3, the polypropylene material is The impact properties, bending strength and chemical resistance are better. When the compounding ratio is between 2:1 and 1:2, the impact properties, flexural modulus and chemical resistance of the polypropylene material are optimized. A reasonable amount of the surface modifier is in the range of 3-5 parts by weight; wherein the polypropylene composition of the fluorine-modified polysiloxane having a density of 0.9 to 2.0 g/cm ³ is added, the chemical resistance is the best, and the mechanical properties are obtained. Also best.

Claims (9)

1. A polypropylene composition characterized by the following components by weight:

   
2. A polypropylene composition according to claim 1, wherein said polypropylene resin is one or more selected from the group consisting of a homopolypropylene resin or a copolymerized polypropylene resin, and has a density ranging from 0.894 to 0.914. g/cm ³ , at 190 ° C, 2.16 Kg load, the melt mass flow rate is 1 ~ 100g / 10min.
3. A polypropylene composition according to claim 1, wherein said high density polyethylene resin is an extrusion grade high density polyethylene having a density of from 0.948 to 0.958 g/cm ³ at 190 ° C. Under the load of 2.16Kg, the melt mass flow rate is 5-10g/10min.
4. The polypropylene composition according to claim 1, wherein the POE-based compound toughening agent is one of a random copolymerized POE or one of a block copolymerized POE or Several kinds of compounds, random copolymerized POE: block copolymerized POE is 1:3 ~ 3:1, preferably 1:2 ~ 2:1, density is 0.857 ~ 0.897g / cm ³ , at 190 ° C, 2.16 Under the Kg load, the melt mass flow rate is 0.5 to 13 g/10 min.
5. The polypropylene composition according to claim 1, wherein the graphene is selected from one or more of mechanically exfoliated graphene and chemically modified graphene, and the sheet is 1 to 5 The layer has a size of 0.1 to 20 μm and a bulk density of 0.01 to 0.1 g/cm ³ .
6. The polypropylene composition according to claim 1, wherein the surface modifier is selected from the group consisting of fluorine-containing resin perfluoropolyether oil having a molecular weight of ≥800,000, and polytetrafluoroethylene having a molecular weight of ≥800,000. One or more of a tetrafluoroethylene-hexafluoropropylene copolymer having a molecular weight of ≥800,000 and a fluorine-modified polysiloxane having a density of 0.9 to 2.0 g/cm ³ ; preferably having a density of 0.9 to 2.0 g/cm ³ fluorine modified polysiloxane.
7. A polypropylene composition according to claim 1 wherein said polypropylene composition further comprises from 0 to 2 parts of pigment.
8. A polypropylene composition according to any of the preceding claims, wherein said polypropylene composition further comprises from 0 to 2 parts of adjuvant.
9. The method for preparing a polypropylene composition according to any one of claims 1 to 8, comprising the steps of: a) using a polypropylene resin, a high-density polyethylene resin, a POE-based compounding toughening agent, Graphene, surface modifier, pigment and auxiliary agent are uniformly mixed in a high-speed mixer; b) is added to a twin-screw extruder, melt-kneaded, and extruded into granules to obtain a polypropylene composition; wherein, melt-kneading The temperature is 170 to 220 ° C, and the screw rotation speed is 350 to 450 rpm.