Recently, Hisense Video Technology Co., Ltd. (abbreviation: Hisense) proposed a MPPO material with high impact resistance, high flow and low shrinkage, and a mineral-filled masterbatch for preparing MPPO materials.
1. Modified plastic for TV back shell
At present, the casings of products such as LCD TVs and laser TVs often use conventional polycarbonate and acrylonitrile-butadiene-styrene copolymers and blends (PC/ABS) and high-impact polystyrene (HIPS). Among them, for the requirements of halogen-free flame retardant in some specific markets, the only halogen-free flame retardant material is PC/ABS. However, the price of flame-retardant PC/ABS is high, so halogen-free and low-cost modified polyphenylene ether (MPPO) is considered the most likely solution.
2. MPPO material and injection molded parts
Polyphenylene ether (PPO) is the fifth largest engineering plastic after polycarbonate PC, polyoxymethylene POM, polyamide PA, thermoplastic polyester PBT and PET. It has the advantages of pollution resistance, high strength and excellent electrical properties. The vast majority of PPO on the market is used after modification, and the modified polyphenylene ether is collectively referred to as MPPO.
Today, the existing injection molded parts of MPPO are often small-sized products such as electric control boxes and electric plastic boxes. The application of MPPO to the rear casing of larger-sized TV sets has not yet been found. Moreover, when MPPO is molded in the existing HIPS or PC/ABS molds, there are problems such as large dimensional shrinkage, poor fluidity, poor impact performance and large post-dimensional shrinkage. Recently, Hisense Video Technology Co., Ltd. (referred to as Hisense) proposed a MPPO material with high impact resistance, high flow and low shrinkage, and a mineral-filled masterbatch for preparing MPPO materials.
3. Hisense calcium carbonate filling masterbatch
Hisense provides an MPPO material, a mineral-filled masterbatch and a preparation method thereof. In parts by weight, the mineral filler masterbatch includes 16-32 parts of calcium carbonate mixture, 48-64 parts of modified talc and 20 parts of polyethylene polymer base material. Wherein, the calcium carbonate mixture includes 15 to 20 parts by weight of calcium carbonate with a particle size of 0.5 μm to 2 μm, 8 to 12 parts by weight of calcium carbonate with a particle size of 4 μm to 6 μm and 70 to 75 parts by weight of calcium carbonate with a particle size of 25 μm to 35 μm; The talc powder includes talc powder and a surface treatment agent in a weight ratio of (4-6):1, and the particle size of the talc powder is 15-25 μm.
It is understood that the medium particle size calcium carbonate and the large particle size calcium carbonate are spherical; in the calcium carbonate mixture, the surfaces of the small particle size calcium carbonate, the medium particle size calcium carbonate and the large particle size calcium carbonate are also wrapped There is a resin layer. The modification process is to use a radio frequency plasma generating device to perform plasma surface treatment on the calcium carbonate mixture, so that the surface of the calcium carbonate mixture is wrapped with a thin resin layer.
MPPO material is made of modified mineral filled masterbatch as raw material, so MPPO material has the advantages of low shrinkage, high impact resistance and high flow, and can share molds with existing PC/ABS or HIPS to form products, especially suitable for making large sized parts.
Epilogue
The ultra-fine processing of calcium carbonate or other non-metallic mineral fillers is the foundation of material production enterprises, and the application technology that the filler is closely combined with the downstream is the key link to reflect its value. They are all calcium carbonate powders, which are also used for filling masterbatches. After ultra-fine, surface modification or spheroidization, their application scenarios and values are still different.