Preparation method and application of toughened polypropylene composite material

Abstract

The invention discloses a preparation method and application of a toughened polypropylene composite material. The preparation method comprises the following steps: S1, drying PPO in an air dry oven; s2, respectively carrying out pretreatment on PP and SEBS; s3, putting PP, SEBS, PPO, maleic anhydride (MAH for short) and an antioxidant into a high-speed mixer, and uniformly mixing to obtain a mixed raw material; and S4, cooling the mixed raw material to normal temperature, conveying the cooled mixed raw material to a twin-screw extruder, enabling the mixed raw material to sequentially pass through a feeding section, a compression section, a melting section and a machine head in the twin-screw extruder, and pelletizing the extruded melt to prepare the toughened polypropylene composite material granules. According to the synthesis method, PP, PPO and SEBS are combined to prepare a novel composite material, and the low-temperature (lower than or equal to-40 DEG C) toughness of the PP material is improved to a certain extent. The modified PP / SEBS / PPO ternary blend can be applied to exterior parts such as automobile bumpers and the like.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of automobile bumper materials, in particular to a preparation method of a toughened polypropylene composite material and application thereof. BACKGROUND

[0002] Polypropylene (PP) is a commonly used thermoplastic material, which has excellent heat resistance, chemical liquid resistance, low density and reusability, and is widely used in various fields such as fibers, films and mechanical parts. However, the defect of insufficient toughness limits its application in practical application. The traditional method to improve the toughness of PP is to blend PP raw materials with elastomers, thermoplastics and the like. However, the strength and modulus should also be considered when improving the toughness.

[0003] The automobile bumper is an important part of vehicle safety, and the material selection is not only related to the appearance, but also directly affects the safety, lightweight level and production cost. Polypropylene material is a material that can be widely used in automobiles, which can realize the lightweight of vehicles (low density), low cost, easy processing and good chemical resistance. However, the existing PP material also has many defects, such as poor low-temperature toughness, poor heat resistance and poor aging resistance. In the selection of the existing automobile bumper material, PP / EPDM / talcum powder has become an absolute mainstream because of its excellent comprehensive performance and outstanding cost-effectiveness. By adding EPDM (ethylene-propylene rubber) toughening, talcum powder (TD) reinforcing rigidity, and anti-ultraviolet agent and stabilizer to improve the weather resistance on the basis of PP, the impact resistance, rigidity, dimensional stability and environmental aging resistance required by the bumper are well balanced. However, the toughness of the existing PP / EPDM / talcum powder composite material under low temperature conditions cannot fully meet the requirements of automobile bumpers. SUMMARY

[0004] One of the purposes of the present application is to provide a preparation method of a toughened polypropylene composite material. The synthesis method combines PP with polyphenyl ether (PPO) and styrene-ethylene-butylene-styrene block copolymer (SEBS) to produce a new composite material, which improves the low-temperature (≦-40℃) toughness of the PP material to a certain extent. The modified PP / SEBS / PPO ternary blend can be applied to automobile bumpers and other exterior parts.

[0005] The second purpose of the present application is to provide an application of a toughened polypropylene material to an automobile bumper.

[0006] The present application provides the following solutions:

[0007] According to one aspect of the present application, the present application provides a preparation method of a toughened polypropylene composite material, comprising the following steps:

[0008] S1. Place the PPO in a forced-air drying oven for drying;

[0009] S2. Preprocess PP and SEBS separately;

[0010] S3. Put PP, SEBS, PPO, maleic anhydride (abbreviated as MAH) and antioxidant into a high-speed mixer and mix evenly to obtain mixed raw materials;

[0011] S4. After cooling the mixed raw materials to room temperature, they are fed into a twin-screw extruder. The mixed raw materials pass through the feeding section, compression section, melting section and die head in the twin-screw extruder in sequence. The extruded melt is granulated to produce toughened polypropylene composite material granules.

[0012] Furthermore, in step S1, the drying temperature is 100-120℃ and the time is 2-4 hours.

[0013] Furthermore, in step S2, the pretreatment involves placing the sample at 20-30°C and 45-55% humidity for 20-30 hours.

[0014] Furthermore, in step S3, the antioxidant is selected from one or more of the following substances: 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1076 (octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and 626 (bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite).

[0015] Furthermore, in step S3, the mass ratio of PP, SEBS, PPO, maleic anhydride and antioxidant is (90-110):(10-20):(10-25):(4-10):(0.3-0.5).

[0016] Furthermore, in step S3, the high-speed mixer operates at a speed of 800-1200 rpm for 4-6 minutes.

[0017] Furthermore, in step S4, the temperature of the feeding section is 170-190℃, the temperature of the compression section is 200-230℃, the temperature of the melting section is 240-260℃, and the temperature of the die head is 240-260℃.

[0018] Furthermore, in step S4, the main motor speed of the twin-screw extruder is 300-400 rpm; the feeding speed is 45-55 kg / h.

[0019] According to two aspects of the present invention, the present invention provides an application of toughened polypropylene material in automobile bumpers.

[0020] Through the above scheme, the following beneficial technical effects are obtained:

[0021] In order to improve the poor low-temperature toughness of the PP material, the PP is mixed with PPO and SEBS in the application. Since the elastomer particles of SEBS are blended in the PP, the SEBS particles can absorb part of the impact performance when impacted, and can inhibit the crack growth to a certain extent, so as to change the brittle fracture of the PP material into ductile fracture. Blending SEBS in the PP alone can improve the toughness while reducing the strength of the PP material, so some PPO is added to improve the rigidity while adding SEBS. However, PPO is a polar, amorphous polymer, and PP is a non-polar polymer, which are difficult to be compatible, so a solubilizing agent is needed to make them uniformly mixed.

[0022] The solubilizing agent maleic anhydride (MAH) in the application is a solubilizing agent with superior performance, which can react with the hydroxyl or amino group at the end of the PPO molecular chain to form a firm chemical bond, so as to make the PPO and SEBS uniformly distributed in the PP to form a continuous phase, that is, the MAH has a synergistic effect with the SEBS and PPO, thereby improving the toughness and strength of the PP material.

[0023] The simply supported beam notched impact strength of the toughened polypropylene composite material PP / SEBS / PPO ternary blend prepared in the application is >=3.2KJ / m 2 .

[0024] The PP / SEBS / PPO ternary blend composite material prepared in the application has good mechanical properties, meets the demand of high modulus and high impact resistance of materials in the engineering field such as automobiles, and can be applied to exterior parts such as bumpers. The preparation process of the application is simple, recyclable, low in cost, safe and reliable. DETAILED DESCRIPTION

[0025] The technical solutions of the application will be described below in a clear and complete manner. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0026] As an aspect of the application, a preparation method of a toughened polypropylene composite material comprises the following steps:

[0027] S1, drying PPO in a blast drying oven;

[0028] S2, pretreating the dried PPO, PP and SEBS respectively;

[0029] S3, put PP, SEBS, PPO, maleic anhydride (abbreviation: MAH) and antioxidant into a high-speed mixer and mix uniformly to obtain a mixed raw material;

[0030] S4, after the mixed raw material is cooled to room temperature, it is transported to a double screw extruder, and the mixed raw material sequentially passes through a feeding section, a compression section, a melting section and a die head in the double screw extruder, the extruded melt is cut into particles, and toughened polypropylene composite material particles are prepared.

[0031] According to some embodiments of the present application, in step S1, the drying temperature is 100-120℃, and the time is 2-4h.

[0032] According to some embodiments of the present application, in step S2, the pretreatment is placed at 20-30℃ and 45-55% humidity for 20-30h.

[0033] According to some embodiments of the present application, in step S3, the antioxidant is selected from one or more of the following: 1010 (tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, 1076 (β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecanol), 626 (bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite).

[0034] According to some embodiments of the present application, in step S3, the mass ratio of PP, SEBS, PPO, maleic anhydride and antioxidant is (90-110):(10-20):(10-25):(4-10):(0.3-0.5).

[0035] According to some embodiments of the present application, in step S3, the operating speed of the high-speed mixer is 800-1200rpm, and the time is 4-6min.

[0036] According to some embodiments of the present application, in step S4, the feeding section temperature is 170-190℃, the compression section temperature is 200-230℃, the melting section temperature is 240-260℃, and the die head temperature is 240-260℃.

[0037] According to some embodiments of the present application, in step S4, the main machine speed of the double screw extruder is 300-400rpm, and the feeding speed is 45-55kg / h.

[0038] As another aspect of the present application, the present application provides a toughened polypropylene material for use in automobile bumpers.

[0039] Example 1

[0040] A preparation method of a toughened polypropylene composite material, comprising the following steps:

[0041] 1) PPO was dried in a blast drying oven at 110°C for 3 hours;

[0042] 2) After taking out, PP, SEBS were respectively placed at 25°C, humidity 50% for 24h for pretreatment;

[0043] 3) The raw materials were weighed according to the ratio of PP:SEBS:PPO:MAH:antioxidant = 100:12:10:5:0.3, and put into a high-speed mixer for mixing for 5 minutes to ensure uniform mixing of each component;

[0044] 4) The mixed mixture was placed into a twin-screw extruder after being cooled to room temperature, and the temperature of each stage was set. The feeding section was 180°C, the compression section was 200°C-230°C, the melting section was 240°C-260°C, and the die head was 240°C-260°C. First, preheat the machine, then add the material to the feeding port when the temperature reaches the set value, adjust the main machine speed to 300-400 rpm and the feeding speed to 45 kg / h, and finally cut the extruded melt into particles to produce PP / SEBS / PPO ternary blend polypropylene composite granules.

[0045] Example 2

[0046] A method for preparing a toughened polypropylene composite material, comprising the following steps:

[0047] 1) PPO was dried in a blast drying oven at 110°C for 3 hours;

[0048] 2) After taking out, PP, SEBS were respectively placed at 25°C, humidity 50% for 24h for pretreatment;

[0049] 3) The raw materials were weighed according to the ratio of PP:SEBS:PPO:MAH:antioxidant = 100:20:10:5:0.3, and put into a high-speed mixer for mixing for 5 minutes to ensure uniform mixing of each component;

[0050] 4) The mixed mixture was placed into a twin-screw extruder after being cooled to room temperature, and the temperature of each stage was set. The feeding section was 180°C, the compression section was 200°C-230°C, the melting section was 240°C-260°C, and the die head was 240°C-260°C. First, preheat the machine, then add the material to the feeding port when the temperature reaches the set value, adjust the main machine speed to 300-400 rpm and the feeding speed to 45 kg / h, and finally cut the extruded melt into particles to produce PP / SEBS / PPO ternary blend polypropylene composite granules.

[0051] Example 3

[0052] A method for preparing a toughened polypropylene composite material, comprising the following steps:

[0053] 1) Drying PPO in a blast drying oven at 110℃ for 3 hours;

[0054] 2) After taking out, put PP and SEBS respectively in the condition of 25℃ and humidity 50% for 24h to pre-treat;

[0055] 3) According to the proportion of PP:SEBS:PPO:MAH:antioxidant = 100:10:15:7.5:0.3, weigh the raw materials and put them into the high-speed mixer to mix for 5 minutes to ensure that the components are evenly mixed;

[0056] 4) Put the mixed mixture into the double screw extruder after cooling to room temperature, set the temperature of each stage. The feeding section is 180℃, the compression section is 200℃-230℃, the melting section is 240℃-260℃, and the die head is 240℃-260℃. First, preheat the machine, and then add the material to the feeding port after the temperature reaches the set value. Adjust the main machine speed to 300-400 rpm and the feeding speed to 45 kg / h. Finally, cut the extruded melt into particles to make PP / SEBS / PPO ternary blend polypropylene composite granules.

[0057] Put the granules into the injection molding machine to inject 80mm*10mm*4mm samples. After placing them at ≦-40℃ for 4h, conduct a simply supported beam unnotched test, and conduct a tensile strength test on 5A type samples. The test results and comparison results are shown in Table 1 below:

[0058]

[0059] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the context of the prior art, and unless specifically defined, should not be interpreted in an idealized or overly formal sense.

[0060] For the method embodiments, for the sake of simple description, they are all expressed as a series of action combinations, but those skilled in the art should know that the embodiments of the present application are not limited by the order of the described actions, because according to the embodiments of the present application, certain steps can be performed in other order or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily essential for the embodiments of the present application.

[0061] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A process for the production of a toughened polypropylene composite material, characterized in that, It comprises the following steps: S1, PPO is placed in a drying oven for drying; S2, PP and SEBS are pretreated respectively; S3, PP, SEBS, PPO, maleic anhydride (referred to as: MAH) and antioxidant are put into a high-speed mixer for mixing uniformly to obtain mixed raw materials; S4, the mixed raw materials are cooled to room temperature and then transported to a twin-screw extruder, the mixed raw materials pass through a feeding section, a compression section, a melting section and a die head in the twin-screw extruder in sequence, the extruded melt is cut into particles, and toughened polypropylene composite material pellets are prepared.

2. The process for the production of a toughened polypropylene composite according to claim 1, characterized in that: In step S1, the drying temperature is 100-120℃, and the time is 2-4h.

3. The process for the production of toughened polypropylene composites according to claim 1, characterized in that: In step S2, the pretreatment is placed at 20-30℃ and humidity of 45-55% for 20-30h.

4. The process for the production of the toughened polypropylene composite material according to claim 1, characterized by the fact that: In step S3, the antioxidant is selected from one or more of the following substances: antioxidant 1010, antioxidant 1076, antioxidant 626.

5. The process for the production of toughened polypropylene composite material as claimed in claim 1, wherein: In step S3, the mass ratio of PP, SEBS, PPO, maleic anhydride and antioxidant is (90-110):(10-20):(10-25):(4-10):(0.3-0.5).

6. The process for the production of toughened polypropylene composites as claimed in claim 1, wherein: In step S3, the running speed of the high-speed mixer is 800-1200 rpm, and the time is 4-6 min.

7. The process for the production of toughened polypropylene composites as claimed in claim 1, wherein: In step S4, the feeding section temperature is 170-190℃, the compression section temperature is 200-230℃, the melting section temperature is 240-260℃, and the die head temperature is 240-260℃.

8. The process for the production of the toughened polypropylene composite material according to claim 1, characterized by: In step S4, the main machine speed of the twin-screw extruder is 300-400 rpm; and the feeding speed is 45-55 kg / h.

9. The application of the toughened polypropylene material prepared by the preparation method of any one of claims 1-8 to automobile bumpers.

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