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Special low-shrinkage polypropylene compound for automobile bumper and preparation method thereof

A low-shrinkage technology for automobile bumpers, which is applied in the field of polypropylene composites for low-shrinkage automobile bumpers and its preparation, can solve problems that affect bumper assembly, poor dimensional stability, and affect the appearance of automobiles. Warpage, high fluidity, and the effect of overcoming severe floating fibers

Inactive Publication Date: 2013-02-06
SHANGHAI KINGFA SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Traditional polypropylene composite materials for bumpers are generally filled with talcum powder to increase rigidity. At the same time, a large amount of thermoplastic elastomer is added to ensure its toughness. The shrinkage rate of this bumper material is extremely large, especially after shrinkage. Dimensional stability is poor, and the back shrinkage after painting is very large and unstable, which affects the assembly of the bumper, and also causes "surface difference", which affects the appearance of the car

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The first step: 77 kg of polypropylene PP M2600R (MI=25g / 10min), 0.4 kg of phenolic heat stabilizer Irganox 1010, 0.1 kg of thioester antioxidant DLTP, and 0.5 kg of polypropylene special nucleating agent NA- 11 (produced by Japan Asahi Denka), 10 kilograms of styrene-butadiene-styrene triblock copolymer SBS4402 (produced by Yanshan Petrochemical Company), 2 kilograms of maleic anhydride grafted styrene-butadiene-styrene TRD -318S (produced by Sruida Plastic Industry Co., Ltd.), 5 kg of 3000-mesh ultra-fine talcum powder are fully mixed with a high-speed mixer;

[0033] The second step: the mixture obtained in the first step is transported to a twin-screw extruder with a length-to-diameter ratio of 60:1 at a rate of 95 kg / hour for melting and dispersion, and at the same time, 5 kg of short-cut alkali-free flat glass fibers NITTOBOCSG3PA- 870 (the length-to-diameter ratio of the cross-sectional axis is=2) is added with a rate of 5 kg / hour from the side feeding port by a ...

Embodiment 2

[0038] The first step: 63 kg of polypropylene PP BX3900 (MI=60g / 10min), 0.5 kg of phenolic heat stabilizer 1010, 0.5 kg of antioxidant DSTP, 0.5 kg of ethylene bis stearic acid amide EBS (Kao Japan), 0.5 kg polypropylene nucleating agent NA-11 (Yuyao Tiannuo Plastic Chemical Co., Ltd.), 15 kg polyethylene HDPE5000S (Yanshan Petrochemical), 5 kg maleic anhydride grafted polyethylene GR320 (Dow, USA), 8 kg 5000 Mesh ultra-fine talc powder is fully mixed with a high-speed mixer;

[0039] The second step: the mixture obtained in the first step is transported to the twin-screw extruder with a length-to-diameter ratio of 30:1 at a rate of 93 kg / hour to melt and disperse, while 7 kg of chopped alkali-free flat glass fiber NITTOBOCSG3PA- 820 (the length-to-diameter ratio of the cross-sectional axis is=4) is added with a rate of 7 kg / hour from the side feed port by a weight-loss type weighing scale, extruded and granulated, and the temperature of each section of the extruder is set to ...

Embodiment 3

[0044] The first step: 45 kg of polypropylene PP BX3920 (MI=100g / 10min), 1 kg of phenolic heat stabilizer 1076, 1 kg of antioxidant DLTP, 2 kg of polypropylene special nucleating agent NA-21 (Japan Asahi Denka ), 20 kg of styrene-butadiene-styrene triblock copolymer SBS 4402 (Yanshan Petrochemical), 6 kg of maleic anhydride grafted styrene-butadiene-styrene TRD-318S (Sruida Plastic Industry ), 15 kg of 3000-mesh talcum powder are fully mixed with a high-mixer;

[0045] The second step: the mixture obtained in the first step is transported to a twin-screw extruder with a length-to-diameter ratio of 40:1 at a rate of 90 kg / hour to melt and disperse, and at the same time, 10 kg of chopped alkali-free flat glass fiber CS 7928 , BAYERAG, Germany (with elliptical cross-section,) is added with the rate of 10 kilograms / hour from the side feeding port by loss-in-weight metering scale, extrudes granulation, and the temperature of each section of extruder is set to 240 ℃, obtains low Sh...

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Abstract

The invention discloses a special low-shrinkage polypropylene compound for an automobile bumper and a preparation method thereof. The special low-shrinkage polypropylene compound for the automobile bumper is characterized by being prepared by the following components according to weight percent: 66-78% of polypropylene, 0-2% of heat stabilizer, 0-2% of processing aid, 0-2% of special nucleating agent for polypropylene, 10-20% of toughening agent, 2-8% of compatilizer, 5-15% of ultrafine talcum powder and 5-10% of chopped flat fiberglass. The preparation method comprises the following steps of: after mixing all the raw materials, adding the mixture into a twin-screw extruder with the length-diameter ratio of 30-60:1 for melting and dispersing, and simultaneously feeding the chopped flat fiberglass into the twin-screw extruder from a side feeding mouth for extrusion and granulation to obtain the product. The material disclosed by the invention has high liquidity, rigidity and heat resistance, low shrinkage and after shrinkage / high dimensional stability and impact, thus meeting the requirements for the development of automobile bumper materials.

Description

technical field [0001] The invention relates to a special polypropylene compound for automobile bumper with low shrinkage rate and a preparation method thereof, belonging to the technical field of polymer materials. Background technique [0002] The car bumper is a safety device that absorbs and moderates external impact and protects the front and rear of the car body. At present, most automobile bumpers are made of plastic, and polypropylene composite materials are the first choice for making bumpers. [0003] With the development of the automobile industry, the automobile bumper, as an important safety device, is also on the road of innovation. In addition to maintaining the original protection function, the front and rear bumpers of today's cars also pursue harmony and unity with the shape of the car body. As a very large automotive exterior trim, the bumper has a very important dimensional precision. After assembly, no "surface difference" is allowed, which affects the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L23/10C08K13/04C08K7/14C08K3/34
Inventor 陈延安李国明程文超李志平周英辉孙刚丁超
Owner SHANGHAI KINGFA SCI & TECH