Scratch-resistant high-stress-whitening-resistant glass fiber reinforced polypropylene compound as well as preparation method and application of scratch-resistant high-stress-whitening-resistant glass fiber reinforced polypropylene compound

Abstract

The invention relates to a glass fiber reinforced polypropylene composition with scratch resistance and high stress whitening resistance as well as a preparation method and application of the glass fiber reinforced polypropylene composition. The glass fiber reinforced polypropylene compound is prepared from 70 to 90 parts of polypropylene, 1 to 10 parts of polyolefin elastomer, 1 to 10 parts of high-density polyethylene, 1 to 5 parts of compatilizer, 0.1 to 0.5 part of scratch-resistant additive, 1 to 5 parts of antioxidant master batch, 0.2 to 1 part of stabilizer, 5 to 20 parts of high-performance glass fiber and 0.5 to 2.0 parts of toner (0.2 to 1.0 part of zinc sulfide), homo-polypropylene and zinc sulfide with a hexagonal phase structure used in the glass fiber reinforced polypropylene compound have high crystal integrity and few defects in a product, and the crystals are fine and can effectively scatter light rays, so that the scratch resistance is good while the high mechanical property of the product is maintained, and the service life of the product is prolonged. The problem that the light-colored surface of the existing glass fiber reinforced polypropylene is prone to stress whitening is also solved, the preparation is simple, the yield is high, and the practical value is relatively high.

Description

Technical Field

[0001] The present invention relates to the technical field of modified polypropylene, and in particular to a scratch-resistant, high-stress-whitening-resistant glass fiber reinforced polypropylene composite and a preparation method thereof. Background Art

[0002] Stress whitening is a large number of microcracks or silver streaks that accumulate when the material is under stress. The surface appears white due to the change in refraction in this area.

[0003] Filled polypropylene materials are beneficial to the nucleation and crystallization of PP and are good for stress whitening resistance. With the enrichment of the colors of automobile interiors, higher requirements are put forward for the stress whitening resistance of filled polypropylene materials of various colors. Affected by the color, stress whitening is not easy to be covered and is more likely to be revealed.

[0004] At present, there are existing technologies reporting on the research on stress whitening of filled PP materials. Generally speaking, the solution is to add elastomers, anti-stress whitening agents, etc. to filled PP materials. For example, as described in Chinese patent application CN109161096A, the good compatibility of propylene-based elastomers and propylene-based materials makes a good contribution to the stress whitening resistance of polypropylene materials; the transparent powder used in the anti-stress whitening transparent masterbatch described in Chinese patent application CN107641253A has a high refractive index and can effectively cover the stress whitening phenomenon, but this method is ineffective for opaque filled PP.

[0005] Therefore, it is necessary to invent a glass fiber reinforced polypropylene composite with high scratch resistance and stress whitening resistance. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned technology, the purpose of the present invention is to improve the stress whitening resistance of filled PP with color requirements by coordinating two basic color powders of carbon black and zinc sulfide and selecting homopolymer polypropylene. The hexagonal phase zinc sulfide has strong diffuse reflection, and its structure can help the polypropylene material to further nucleate and crystallize. To this end, the present invention provides a method for preparing a scratch-resistant and highly stress-whitening-resistant glass fiber reinforced polypropylene composite.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A scratch-resistant and highly stress-resistant glass fiber reinforced polypropylene composite and a preparation method thereof, comprising 70-90 parts of polypropylene, 1-10 parts of polyolefin elastomer, 1-10 parts of high-density polyethylene, 1-5 parts of a compatibilizer, 0.1-0.5 parts of a scratch-resistant additive, 1-5 parts of an antioxidant masterbatch, 0.2-1 parts of a stabilizer, 5-20 parts of high-performance glass fiber, 0.5-2.0 parts of a color powder, and 0.2-1 parts of zinc sulfide.

[0009] The toner contains 0.2-1 part of carbon black.

[0010] The polypropylene is homopolymer polypropylene.

[0011] The zinc sulfide is zinc sulfide with a hexagonal crystal phase structure.

[0012] A method for preparing a scratch-resistant and stress-whitening glass fiber reinforced polypropylene composite comprises the following steps:

[0013] S1: according to the weight ratio, appropriate amounts of homopolymer polypropylene, polyolefin elastomer, high-density polyethylene, compatibilizer, antioxidant masterbatch, stabilizer, high-performance glass fiber, and hexagonal zinc sulfide are added to a high-speed mixer and stirred evenly to obtain product I for standby use;

[0014] S2: placing the product I obtained in step 1 into an oven for drying to obtain product II for later use;

[0015] S3: Add the product II obtained in step 2 to a twin-screw extruder for blending, melt extrusion and granulation to obtain the final product.

[0016] In step 1, the stirring temperature is room temperature, the stirring speed is 500 rm, and the stirring time is 2-5 min to obtain product I;

[0017] In step 2, the baking temperature is 100° C. and the baking time is 2-4 h to obtain product II;

[0018] In step 3, the extrusion temperatures of the twin-screw extruder from the hopper to the die head are 175-190°C, 180-190°C, 185-200°C, 190-205°C, and 195-210°C, respectively.

[0019] The advantages of the present invention are:

[0020] 1. Further enhance the stress whitening resistance of filled polypropylene by using effective stress-resistant ingredients in a coordinated manner

[0021] 2. While effectively resisting stress, it also further improves scratch resistance

[0022] 3. Fundamentally solve the problem of stress whitening by continuously reducing crystal defects DETAILED DESCRIPTION

[0023] A scratch-resistant, high-stress-resistant, whitening glass fiber reinforced polypropylene composite and a preparation method thereof, comprising 70-90 parts of polypropylene, 1-10 parts of polyolefin elastomer, 1-10 parts of high-density polyethylene, 1-5 parts of a compatibilizer, 0.1-0.5 parts of a scratch-resistant additive, 1-5 parts of an antioxidant masterbatch, 0.2-1 parts of a stabilizer, 5-20 parts of high-performance glass fiber, and 0.5-2.0 parts of a color powder;

[0024] The scratch-resistant, high-stress-resistant, whitening glass fiber reinforced polypropylene composite further comprises 0.5-1 part of white carbon black.

[0025] Among them, polypropylene is homopolymer polypropylene. The polyolefin elastomer is an octane chain, the compatibilizer is a metallocene ethylene-octene elastomer grafted with maleic anhydride, and the grafting rate is 0.6-0.8%. The antioxidant masterbatch is mainly DSTP, antioxidant 168 and antioxidant 1010. The stabilizer is mainly a hindered amine stabilizer. Zinc sulfide has a hexagonal crystal phase structure.

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example 1

[0028] S1, according to the weight ratio, takes 59.7kg of homopolymer polypropylene, 5kg of polyolefin elastomer, 1kg of high-density polyethylene, 3kg of compatibilizer, 0.5kg of antioxidant masterbatch, 0.25kg of stabilizer, 30kg of high-performance glass fiber, 0.1kg of scratch-resistant additive, 0.7kg of hexagonal zinc sulfide, and 0.25kg of carbon black, and adds them into a high-speed mixer for uniform stirring to obtain product I for standby use:

[0029] S2: placing the product I obtained in step 1 into an oven for drying to obtain product II for later use;

[0030] S3: Add the product II obtained in step 2 to a twin-screw extruder for blending, melt extrusion and granulation to obtain the final product.

[0031] In step 1, the stirring temperature is room temperature, the stirring speed is 500 rm, and the stirring time is 2-5 min to obtain product I;

[0032] In step 2, the baking temperature is 100° C. and the baking time is 2-4 h to obtain product II;

[0033] In step 3, the extrusion temperatures of the twin-screw extruder from the hopper to the die head are 175-190°C, 180-190°C, 185-200°C, 190-205°C, and 195-210°C, respectively.

[0034] Example 2

[0035] S1, by weight, takes 70.5 kg of homopolypropylene, 5 kg of polyolefin elastomer, 1 kg of high-density polyethylene, 2 kg of compatibilizer, 0.5 kg of antioxidant masterbatch, 0.25 kg of stabilizer, 20 kg of high-performance glass fiber, 0.1 kg of scratch-resistant additive, 0.4 kg of hexagonal zinc sulfide, and 0.25 kg of carbon black, and adds them into a high-speed mixer for uniform stirring to obtain product I for standby use;

[0036] S2: placing the product I obtained in step 1 into an oven for drying to obtain product II for later use;

[0037] S3: Add the product II obtained in step 2 to a twin-screw extruder for blending, melt extrusion and granulation to obtain the final product.

[0038] In step 1, the stirring temperature is room temperature, the stirring speed is 500 rm, and the stirring time is 2-5 min to obtain product I;

[0039] In step 2, the baking temperature is 100° C. and the baking time is 2-4 h to obtain product II;

[0040] In step 3, the extrusion temperatures of the twin-screw extruder from the hopper to the die head are 175-190°C, 180-190°C, 185-200°C, 190-205°C, and 195-210°C, respectively.

[0041] Example 3

[0042] S1, by weight, takes 80.0 kg of homopolypropylene, 5 kg of polyolefin elastomer, 1 kg of high-density polyethylene, 2 kg of compatibilizer, 0.5 kg of antioxidant masterbatch, 0.05 kg of stabilizer, 10 kg of high-performance glass fiber, 0.1 kg of scratch-resistant additive, 0.2 kg of hexagonal zinc sulfide, and 0.25 kg of carbon black, and adds them into a high-speed mixer for uniform stirring to obtain product I for standby use;

[0043] S2: placing the product I obtained in step 1 into an oven for drying to obtain product II for later use;

[0044] S3: Add the product II obtained in step 2 to a twin-screw extruder for blending, melt extrusion and granulation to obtain the final product.

[0045] In step 1, the stirring temperature is room temperature, the stirring speed is 500 rm, and the stirring time is 2-5 min to obtain product I;

[0046] In step 2, the baking temperature is 100° C. and the baking time is 2-4 h to obtain product II;

[0047] In step 3, the extrusion temperatures of the twin-screw extruder from the hopper to the die head are 175-190°C, 180-190°C, 185-200°C, 190-205°C, and 195-210°C, respectively.

[0048] Comparative Examples 1-3

[0049] The same extrusion process parameters are used, except that hexagonal zinc sulfide and scratch-resistant additive are not used, and the other parameters are the same as those in Examples 1-3. After all the required materials are uniformly mixed, a twin-screw extruder is used for extrusion granulation to obtain the final product.

[0050] Table 1 Physical parameters and stress whitening test of examples and comparative examples

[0051]

[0052]

[0053] It can be seen from the above that, for glass fiber reinforced PP with the same glass fiber content, the toughness of the glass fiber reinforced PP material prepared by the present invention is improved, while the stiffness is not much different, and the effect of resisting stress whitening is better, and the cost performance is higher.

Claims

1. A scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite, characterized in that: The invention is composed of the following raw materials in parts by weight: 70-90 parts of polypropylene, 1-10 parts of polyolefin elastomer, 1-10 parts of high-density polyethylene, 1-5 parts of compatibilizer, 0.1-0.5 parts of scratch-resistant additive, 1-5 parts of antioxidant masterbatch, 0.2-1 parts of stabilizer, 5-20 parts of high-performance glass fiber, 0.5-2.0 parts of color powder and 0.2-1.0 parts of zinc sulfide.

2. A scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite according to claim 1, characterized in that: The toner also includes 0.2-1 part of carbon black.

3. The scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite according to claim 1, characterized in that: The polypropylene is homopolymer polypropylene.

4. The scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite according to claim 1, characterized in that: The zinc sulfide is zinc sulfide with a hexagonal crystal structure.

5. The method for preparing the scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: according to the weight ratio, appropriate amounts of homopolymer polypropylene, polyolefin elastomer, high-density polyethylene, compatibilizer, antioxidant masterbatch, stabilizer, high-performance glass fiber, zinc sulfide, and hexagonal zinc sulfide are added to a high-speed mixer for uniform stirring to obtain product I for standby use; Step 2: Place the product I obtained in step 1 into an oven for drying to obtain product II for later use; Step 3: Add the product II obtained in step 2 to a twin-screw extruder for blending, melt extrusion and granulation to obtain the final product.

6. The method for preparing a scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite according to claim 5, characterized in that: In the step 1, the stirring temperature is room temperature, the stirring speed is 500rm, and the stirring time is 2-5min to obtain product I.

7. The method for preparing a scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite according to claim 5, characterized in that: In the step 2, the baking temperature is 100° C. and the baking time is 2-4 hours to obtain product II.

8. The method for preparing a scratch-resistant and stress-whitening-resistant glass fiber reinforced polypropylene composite according to claim 5, characterized in that: In the step three, the extrusion temperatures of the twin-screw extruder from the hopper to the die head are 175-190°C, 180-190°C, 185-200°C, 190-205°C, and 195-210°C respectively.

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