WO2023143067A1 - Scratch-resistant polypropylene composite material with high impact resistance and high peeling performance, method for preparing same, and use thereof - Google Patents

Abstract

The present invention provides a scratch-resistant polypropylene composite material with high impact resistance and high peeling performance, a method for preparing same, and use thereof. The polypropylene composite material comprises the following components in parts by weight: 100 parts of a polypropylene copolymer, 0-55 parts of a filler, 5-25 parts of a special auxiliary, 10-55 parts of a toughener, 0.01-0.1 part of a scratch-resistant agent, 0.1-1 part of a lubricant, and 0.1-1 part of an antioxidant, wherein the special auxiliary is high-density polyethylene-grafted maleic anhydride. According to the present invention, by means of selecting a high-density polyethylene at a specific density for grafting with maleic anhydride and adding the high-density polyethylene-grafted maleic anhydride into a polypropylene material, the negative effect of the polarity of the scratch-resistant agent on the peeling strength can be reduced, thereby enabling a simultaneous improvement in the scratch resistance and the peeling strength of the polypropylene material. Meanwhile, by means of using a specific polypropylene copolymer as a matrix, the impact strength of the material can be improved on the basis of not reducing the scratch resistance and the peeling strength.

Description

Scratch-resistant polypropylene composite material with high impact resistance and high peeling performance, its preparation method and application technical field

The invention belongs to the field of polymer material modification, and in particular relates to a scratch-resistant polypropylene composite material with high impact resistance and high stripping performance, a preparation method and application thereof.

Background technique

Polypropylene is widely used in automobiles due to its low density, high cost performance, excellent heat resistance, rigidity, chemical corrosion resistance, easy processing and recycling, and has become the largest and fastest growing plastic in automobiles. The fast variety. However, in different application scenarios, higher requirements are placed on the different properties of polypropylene materials. When polypropylene material is used in automotive interior products, it has high requirements on the scratch resistance of the material. However, the surface of polypropylene is easily scratched by external forces, which will greatly affect the appearance of the product and limit its use. Widely used; when used in automotive exterior products, it needs to have better paintability (such as high peel strength or adhesion with paint).

Most of the existing modification methods for scratch resistance are to add scratch resistance agent into polypropylene material, such as Chinese patent CN107075010A to improve the scratch resistance of polypropylene material by adding high density polyethylene, but due to high The high crystallinity and non-polarity of density polyethylene make it have a certain negative impact on the coating peel strength of polypropylene composite materials; CN109705467A forms a layer of protective film on the surface by adding phosphate ester salt and amide wax to improve the coating of the material. Adhesion is improved, but there is no improvement in scratch resistance.

Therefore, the existing polypropylene materials need to be individually modified for different properties in different application scenarios, making the functions of the polypropylene materials relatively single, which brings great inconvenience to the application.

At present, although there are also studies on the comprehensive improvement of scratch resistance and coating performance, such as patent CN113321869A, which uses ultra-high molecular weight grafted glycidyl methacrylate as a special additive to improve the scratch resistance of polypropylene However, the high price of ultra-high molecular weight polyethylene will undoubtedly increase the production cost to a certain extent. Therefore, in order to reduce the production cost, it is necessary to provide a new additive to improve the resistance of polypropylene. While improving the scratch performance and coating performance, the production cost is reduced; at the same time, the impact performance of the composite material still needs to be improved.

And as people pay more attention to product performance, higher requirements are put forward for the performance of polypropylene materials. In addition to good scratch resistance and high peel strength, higher impact resistance is required, so that When it is used in the interior of the car, it has good anti-collision performance, and it can reduce the damage to the human body to a greater extent when the vehicle collides.

Contents of the invention

The purpose of the present invention is to overcome the defects of single function and high production cost of the existing polypropylene material, and provide a scratch-resistant scratch-resistant material with good scratch resistance, coating performance and impact performance, high impact resistance and high peeling performance. Rub polypropylene composite.

Another object of the present invention is to provide a method for preparing the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance.

Another object of the present invention is to provide the application of the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance in the preparation of auto parts.

To achieve the above object, the present invention adopts the following technical solutions:

A high-impact, high-stripping scratch-resistant polypropylene composite material comprising the following components in parts by weight:

Wherein, the copolymerized polypropylene is an ethylene-propylene copolymer with a crystallinity of 75-80%; the special additive is high-density polyethylene grafted with maleic anhydride, and the high-density polyethylene grafted with maleic anhydride Among them, the grafting rate of maleic anhydride is 0.2-2wt%; in the high-density polyethylene grafted with maleic anhydride, the density of high-density polyethylene is 0.950-0.960 g/cm ³ .

It should be noted that the crystallinity of the copolymerized polypropylene in the present invention is measured according to the X-ray diffraction method in the standard "SH/T 1827-2019".

High-density polyethylene grafted maleic anhydride (HDPE-g-MAH), usually used as a surfactant for fillers, is used to improve the dispersibility of fillers in the matrix, but the inventors creatively found that if it is added to In the polypropylene material, it can not only play the role of dispersing the filler, but also reduce the negative impact of the polarity of the scratch-resistant agent on the peel strength, thereby improving the scratch resistance and peel strength of the polypropylene material at the same time, and the cost is far It is lower than the ultra-high molecular weight polyethylene used in CN113321869A, therefore, the production cost of the material is greatly reduced.

As for high-density polyethylene (HDPE), we know that different densities will make HDPE have different characteristics. The inventor has further studied through a large number of experiments and shows that only by grafting the high-density polyethylene and maleic anhydride at a specific density of the present invention and adding it to the polypropylene material, it can be achieved under the addition of a smaller amount of scratch-resistant agent. , to obtain a polypropylene material with excellent scratch resistance, and a smaller amount of scratch resistance agent can further reduce its impact on the peel strength and mechanical properties of the composite material; at the same time, the grafting rate of maleic anhydride will also affect the final Scratch resistance and peel strength of the prepared polypropylene material.

Under the condition of satisfying the above-mentioned scratch resistance and peel strength, the inventors of the present invention found through further research that if a copolymerized polypropylene with a specific ethylene content is selected as the matrix, the obtained composite material can also have excellent impact properties. This is because, in ethylene-propylene copolymerized polypropylene, the random arrangement of ethylene and propylene disrupts the regularity of the molecular chain structure, thus forming crystalline regions and non-crystalline regions in the copolymer, and the non-crystalline regions are soft. Rubber phase, uniformly dispersed in the pores of the crystalline region, the rubber phase provides impact resistance. The high-density polyethylene segment in HDPE-g-MAH has good compatibility with the polyethylene segment in copolymerized polypropylene, so that HDPE-g-MAH is uniformly dispersed in the polypropylene matrix, further improving the composite material. Mechanical properties, especially toughness (i.e. impact resistance); further, the synergistic effect of the rubber phase in polypropylene copolymer, HDPE-g-MAH and toughener can significantly improve the impact properties of the composite. Regarding the content of the rubber phase in the copolymerized polypropylene, the study found that if the rubber phase content is too low (that is, the crystallinity is too high), the impact strength of the composite material is low; as the rubber phase content increases, the impact strength of the composite material decreases. Gradually increase, but when the content of rubber phase increases to a certain extent, the scratch resistance and rigidity of the composite material will decrease. High-impact, high-stripping scratch-resistant polypropylene composite with good scratch resistance, paintability and impact properties.

In order to further improve the scratch resistance and peel strength of the polypropylene material, the grafting ratio of the maleic anhydride is further preferably 0.8-1.5 wt%.

Preferably, the high-density polyethylene has a density of 0.954-0.956 g/cm ³ .

The high-density polyethylene grafted with maleic anhydride can be prepared by conventional grafting methods in the prior art.

In the prior art, the melt grafting method is usually adopted to prepare high-density polyethylene grafted maleic anhydride, which specifically includes the following steps:

S1. high-density polyethylene, maleic anhydride and initiator carry out melt grafting at 160～200 ℃, obtain the grafting mixture containing high-density polyethylene grafted maleic anhydride;

S2. Add xylene to the graft mixture obtained in S1. to purify the high-density polyethylene grafted maleic anhydride, and obtain the high-density polyethylene grafted maleic anhydride after precipitation, filtration, drying and granulation;

Wherein, the weight ratio of high-density polyethylene, maleic anhydride and initiator described in step S1. is 50-65:0.6-1.8:0.4-1.6.

Preferably, the initiator is a peroxide initiator, more preferably di-tert-butyl peroxide (DTBP).

Preferably, the time for the melt grafting is 15-30 minutes.

It should be noted that conventional commercially available high-density polyethylene can be used in the present invention to prepare high-density polyethylene grafted maleic anhydride.

Preferably, the toughening agent is ethylene-α-olefin random copolymer (also known as POE).

Preferably, the anti-scratch agent is an amide type anti-scratch agent.

Further preferably, the anti-scratch agent is one or a combination of erucamide or oleamide.

Preferably, the filler is one or a combination of talcum powder, calcium carbonate or basic magnesium sulfate whiskers. The addition of the filler can improve the rigidity and modulus of the composite material, and further preferably, the filler is basic magnesium sulfate whisker.

Preferably, the lubricant is a stearate.

Further preferably, the stearate is one or a combination of zinc stearate, calcium stearate or magnesium stearate.

Preferably, the antioxidant is hindered phenolic antioxidant and/or phosphite antioxidant.

Further preferably, the hindered phenolic antioxidant is antioxidant 1010; the phosphite antioxidant is antioxidant 168.

The preparation method of the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance comprises the following steps:

After mixing polypropylene, fillers, special additives, toughening agents, anti-scratch agents, lubricants and antioxidants in proportion, it is prepared by melt extrusion, wherein the temperature of melt extrusion is 170-210°C.

Preferably, a 75D co-rotating twin-screw extruder is selected for the melt extrusion. In the twin-screw extruder, from the feeding section to the machine head, the temperature is 170°C, 200°C, 200°C, 210°C, 210°C, 205°C, 205°C, 205°C, 200°C, 200°C.

Application of the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance in the preparation of auto parts.

Compared with prior art, the beneficial effect of the present invention is:

In the present invention, by adding high-density polyethylene grafted maleic anhydride as a special additive into the polypropylene material, the negative impact of the polarity of the scratch-resistant agent on the peel strength can be reduced, and the scratch resistance of the polypropylene material can be improved at the same time. Scratch performance and peel strength, and with the addition of a small amount of scratch-resistant agent, the scratch resistance can reach △L<0.4, and the coating peel strength can reach ≥1000gf/cm. The impact strength of the matrix is above 40kJ/m ² and can be as high as 58kJ/m ² ; and the production process is simple, the production cost is low, and it can be adapted to a polypropylene matrix with a wider melt index, which is conducive to mass production.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

Embodiments of the invention employ the following raw materials:

Ordinary polypropylene PP:

PP-1: Copolymerized polypropylene, BX3900, with a crystallinity of 78%, purchased from Aisika, Korea;

PP-2: Copolymerized polypropylene, EP300M, with a crystallinity of 77%, purchased from China Shipping Shell;

PP-3: Copolymerized polypropylene, BX3950, with a crystallinity of 79%, purchased from Aisika, Korea

PP-4: Copolymerized polypropylene, EP246P, crystallinity is 60%, purchased from Basel;

PP-5: Homopolypropylene, H9018, purchased from Lanzhou Petrochemical;

filler:

Calcium carbonate: 75T, purchased from Changxing Omiya;

Whisker: WS-1S2 (magnesium sulfate basic whisker), purchased from Yingkou Kangru Technology;

Talcum powder: TYT-777A (3000 mesh talc powder), purchased from Liaoning Tianyuan;

Toughener:

POE: commercially available;

Scratch Resistant:

Erucamide: purchased from Shanghai Kaiyin Chemical;

Oleic acid amide: purchased from Shanghai Kaiyin Chemical;

Antioxidant:

Antioxidant 1010: commercially available;

Antioxidant 168: commercially available;

Lubricant:

Zinc stearate: commercially available;

High-density polyethylene:

HDPE-1: Paxon AB50-003, density 0.950g/cm ³ , purchased from ExxonMobil;

HDPE-2: Paxon FD60-018, density 0.954g/cm ³ , purchased from ExxonMobil;

HDPE-3: Paxon BA54-030, density 0.956g/cm ³ , purchased from ExxonMobil;

HDPE-4: HD 7957.04, density 0.960g/cm ³ , purchased from ExxonMobil;

HDPE-5: Paxon AA45-004, density 0.945g/cm ³ , purchased from ExxonMobil;

HDPE-6: Paxon AA60-003, density 0.963g/cm ³ , purchased from ExxonMobil;

Maleic anhydride: purchased from Shandong Longhui Chemical Co., Ltd.;

Di-tert-butyl peroxide: commercially available;

It should be noted that the toughening agent, lubricant and di-tert-butyl peroxide in the examples of the present invention and the comparative examples are all the same.

Among the present invention, high-density polyethylene graft maleic anhydride is prepared by following method:

S1. High-density polyethylene, maleic anhydride and initiator di-tert-butyl peroxide are in a weight ratio of 50～65:0.6～1.8:0.4～1.6, and melt grafting is carried out at 160～180°C for 15～30min to obtain A graft mixture containing high-density polyethylene grafted with maleic anhydride;

S2. Add xylene to the graft mixture obtained in S1. to purify the high-density polyethylene grafted maleic anhydride, and obtain the high-density polyethylene grafted maleic anhydride after precipitation, filtration, drying and granulation;

The high-density polyethylene grafted maleic anhydride of different grafting rates of maleic anhydride can obtain by adjusting the ratio of raw materials and reaction temperature and time, wherein, the grafting rate is grafted to the maleic anhydride on the high-density polyethylene The ratio of the total mass of high-density polyethylene participating in the reaction.

See Table 1 for details.

Table 1 The formula of high-density polyethylene grafted maleic anhydride

Examples 1-20

This example provides a series of scratch-resistant polypropylene composite materials with high impact resistance and high peeling performance, which are prepared according to the formulations in Table 2-4 and the preparation method comprising the following steps:

S1. According to the proportions in Table 2-4, mix polypropylene, fillers, special additives, tougheners, anti-scratch agents, lubricants and antioxidants in a high-speed mixer for 5 minutes, and the speed of the high-speed mixer is 800r /min, the mixture is obtained after mixing evenly;

S2. Put the mixture obtained in S1. in a 75D co-rotating twin-screw extruder at 170-210°C (the temperature of the twin-screw extruder from the feeding section to the machine head is 170°C, 200°C, 200°C, 210°C, 210°C, 205°C, 205°C, 205°C, 200°C, 200°C) by melt extrusion and granulation.

Content of each component in the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance of Table 2 Examples 1-9 (parts by weight)

Content of each component in the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance of Table 3 Examples 10-14 (parts by weight)

Contents of each component in the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance of Table 4 Examples 15-20 (parts by weight)

Comparative example 1

The difference between this comparative example and Example 1 is that no special auxiliary agent high-density polyethylene grafted maleic anhydride was added.

Comparative example 2

The difference between this comparative example and Example 1 is that high-density polyethylene grafted maleic anhydride is replaced with 20.83 parts of high-density polyethylene HDPE-1 and 4.17 parts of maleic anhydride.

Comparative example 3

The difference between this comparative example and Example 1 is that the high-density polyethylene grafted with maleic anhydride was replaced by high-density polyethylene HDPE-1.

Comparative example 4

The difference between this comparative example and Example 1 is that the high-density polyethylene grafted maleic anhydride was replaced by maleic anhydride.

Comparative example 5

The difference between this comparative example and Example 1 is that the special additive is replaced by B1.

Comparative example 6

The difference between this comparative example and Example 1 is that the special additive is replaced by B2.

Comparative example 7

The difference between this comparative example and Example 1 is that the special additive is replaced by B3.

Comparative example 8

The difference between this comparative example and Example 1 is that the special additive is replaced by B4.

Comparative example 9

The difference between this comparative example and Example 1 is that polypropylene is replaced by polypropylene PP-4 with a lower crystallinity.

Comparative example 10

The difference between this comparative example and Example 1 is that polypropylene is replaced by homopolypropylene PP-5.

Performance Testing

The scratch resistance and the peel strength of the polypropylene prepared by the above-mentioned examples and comparative examples are tested, and the specific test methods are as follows:

1. Scratch resistance performance: Tested according to the PV3952-2019-03 standard of Volkswagen OEM, 10N load, Ford STUCCO texture board for testing, the smaller the △L value, the better the scratch resistance performance.

2. Peel strength test: test according to Dongfeng Nissan's standard NES M0141-2006-1;

3. Impact strength test: test according to ISO 180-2000, the notch type is A-type notch;

The test results are detailed in Table 5.

Table 5 performance test results

It can be seen from Table 5 that:

The polypropylene composite material prepared in the embodiment of the present invention can have higher scratch resistance with the addition of a smaller amount of scratch resistance agent, and has better coating performance (peel strength) and impact strength at the same time, Among them, the scratch resistance △L<0.4, the peel strength ≥1000gf/cm, and the impact strength are all above 40kJ/m ² and can be as high as 58kJ/m ² , which can meet the performance and use requirements in auto parts.

The comparative results of Examples 1-6 show that under the synergistic effect of special additives and scratch-resistant agents, the scratch-resistant performance and peel strength of the prepared polypropylene composite material are simultaneously improved; Example 1, Example 7- 9. The comparative results of Examples 12-13 show that the changes in the types and contents of other additives (such as fillers, lubricants, toughening agents, antioxidants, etc.) The influence of scratch performance and peel strength is less; The comparison result of embodiment 1 and embodiment 10-11 shows, the polypropylene of different melt index all can be used for the present invention, and the melt index of polypropylene substrate has a great impact on scratch resistance and peel strength The impact of the invention is relatively small; the comparative results of Example 1 and Example 14 show that the amide scratch-resistant agent used in the present invention can work synergistically with special additives to obtain better scratch-resistant performance and peel strength. polypropylene.

Embodiment 1, embodiment 15-20, the comparison result of comparative example 5-8 can find out that the density of high-density polyethylene in the special auxiliary agent and the grafting rate of maleic anhydride to the scratch resistance of polypropylene composite material and Peel strength has a greater influence on:

Wherein embodiment 1, embodiment 15-17 have selected the special auxiliary agent HDPE-g-MAH of different maleic anhydride graft ratios for use, can find out that along with the raising of maleic anhydride graft ratio, the scratch resistance of material It first increases and then decreases, and the peel strength shows an upward trend. Therefore, in order to ensure that the polypropylene composite material has good scratch resistance and peel strength at the same time, the maleic anhydride grafting rate of the special additive needs to be kept within a certain range. Comparative example 7 has selected the special auxiliary agent of lower maleic anhydride grafting rate, and the scratch resistance and peel strength of the polypropylene composite material prepared are all poor; Comparative example 8 has selected higher maleic anhydride grafting rate Although the peel strength of the prepared polypropylene composite material is significantly improved, the scratch resistance is significantly reduced.

Embodiment 1, embodiment 18-20 selected the special auxiliary agent HDPE-g-MAH that the high density polyethylene of different densities is prepared for use, it can be seen that within the density range of the present invention, the prepared special auxiliary agent is added to the poly In the propylene material, the scratch resistance and peel strength of the polypropylene composite material can be improved at the same time; comparative examples 5 and 6 selected high-density polyethylene outside the scope of the present invention to prepare special additives, and the prepared polypropylene composite material The peel strength was not improved.

Comparative Example 1 did not add special additives, and it can be seen that the peel strength and impact strength of the polypropylene composite material prepared by it were significantly lower than each embodiment of the present invention; Comparative Example 2 selected maleic anhydride and high-density polyethylene to carry out Blending, the scratch resistance, peel strength and impact strength of the prepared polypropylene composite material are significantly reduced compared with the examples; comparative example 3 only adds high-density polyethylene, although its scratch resistance has increased High, but its peel strength and impact strength are significantly lower; Comparative Example 4 only added maleic anhydride, although the peel strength of the prepared polypropylene composite material increased, but it caused the scratch resistance and impact strength of the material to be reduced. Significant decrease in strength.

In comparative example 9, a copolymerized polypropylene with low crystallinity was selected, and the scratch resistance of the obtained composite material was obviously poor; in comparative example 10, a homopolypropylene with high crystallinity that did not contain ethylene segments was selected, and the obtained composite The impact strength of the material is poor.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (10)

A scratch-resistant polypropylene composite material with high impact resistance and high peeling performance, characterized in that it includes components calculated in parts by weight as follows:

Wherein, the copolymerized polypropylene is an ethylene-propylene copolymer with a crystallinity of 75-80%; the special additive is high-density polyethylene grafted with maleic anhydride, and the high-density polyethylene grafted with maleic anhydride Among them, the grafting rate of maleic anhydride is 0.2-2.0 wt %; in the high-density polyethylene grafted with maleic anhydride, the density of high-density polyethylene is 0.950-0.960 g/cm ³ . The scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to claim 1, characterized in that the grafting rate of the maleic anhydride is 0.8-1.5 wt%. The scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to claim 1, characterized in that the density of the high-density polyethylene is 0.954-0.956 g/cm ³ . The scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to claim 1, wherein the toughening agent is an ethylene-α-olefin random copolymer. The scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to claim 1, wherein the scratch-resistant agent is an amide type scratch-resistant agent. The scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to claim 1, wherein the filler is one or more of talcum powder, calcium carbonate or basic magnesium sulfate whiskers combination. The scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to claim 1, wherein the filler is basic magnesium sulfate whisker. The scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to claim 1, wherein the lubricant is stearate. The preparation method of the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance according to any one of claims 1 to 8, comprising the following steps: After mixing polypropylene, fillers, special additives, toughening agents, anti-scratch agents, lubricants and antioxidants in proportion, it is prepared by melt extrusion, wherein the temperature of melt extrusion is 170-210°C. The application of the scratch-resistant polypropylene composite material with high impact resistance and high peeling performance described in any one of claims 1 to 8 in the preparation of auto parts.