The surface modification of talc powder can improve the interface affinity between talc powder and polymer, and improve the dispersion state of talc powder filler in polymer base material. In this way, talc powder not only plays an incremental role in the composite material, but also plays a role in enhancing the modification effect, so as to improve the physical and mechanical properties of the composite material, so that talc can be better applied and more widely used Application field.

1. Modification of talc titanate coupling agent

The function of titanate coupling agent is to form a single molecule covering film on the surface of the filler, change its original hydrophilic properties, and make the surface properties of the filler fundamentally change.

Due to the unique structure of titanate coupling agent, it has good coupling effect on polymer and filler, so it can improve the dispersion and fluidity of filler, and improve the elongation at break, impact and flame retardancy of composite materials.

1) Modification method

Dry modification: talcum powder is stirred and dried in a high-speed mixer preheated to 100 ℃ - 110 ℃, and then the measured titanate coupling agent (diluted with appropriate 15 × white oil) is added evenly, and stirred for several minutes to obtain the modified talcum powder filler.

Wet modification: After diluted with a certain amount of solvent, a certain amount of talcum powder was added to the titanate coupling agent, stirred at 95 ℃ for 30 minutes, filtered and dried to obtain the modified talcum powder product.

2) Application characteristics

The talc filler modified by titanate coupling agent can improve the compatibility with polypropylene (PP), reduce the viscosity of the system, increase the fluidity of the system, improve the processing performance of the system, reduce the deformation, improve the dimensional stability, and expand the application scope of PP.

2. Modification of talc aluminate coupling agent

1) Modification method

A proper amount of aluminate (e.g. L2 type) is dissolved in solvent (e.g. liquid paraffin), added with 1250 mesh of micro talcum powder dried for grinding for 30min to modify, and kept at a constant temperature for a period of time at 100 ℃, after cooling, the modified product can be obtained.

2) Application characteristics

Compared with ordinary talc powder, the viscosity of talc powder modified by aluminate in liquid paraffin decreased significantly, the time of water penetration increased, and the effect of organic hydrophobic modification was obvious. The mechanical properties, such as tensile strength and elongation, were improved by replacing the semi reinforced carbon black filled rubber with talcum powder modified by aluminate. At the same time, there is a large amount of substitution. It can reduce cost and environmental pollution.

3. Organic polymer modification of talcum powder

The talc powder was modified by TDI and HPA. The composite particles were composed of PMMA and PMMA co PBA.

1) Preparation of composite particles

The organic talcum powder, toluene, initiator, butyl acrylate (BA) and divinylbenzene (DVB), which were treated by TDI and HPA and further purified, were put into the reactor, stirred evenly, and the following solutions were added continuously in proper proportion: MMA, Ba, DVB, toluene, azo-2 under the condition of maintaining the temperature of 75 ± 5 ℃ Isobutyronitrile. After dripping, the reaction was maintained at 80 ± 5 ℃ for 2.5h. Then, the solvent and unreacted matter are evaporated under reduced pressure (the absolute pressure is about 8KPa, and the temperature is not less than 85 ℃), and then extracted by Soxhlet extractor with isopropanol for 24h, and then washed, dried and screened to obtain the surface organic polymer composite talcum powder particles.

2) Application characteristics

The tensile strength and impact strength of composite particles of talc powder coated with polymer were significantly higher than those of talc powder filled directly. The impact strength and tensile strength of coated particles were increased by (119 ± 4)%, while the tensile strength and impact strength of flexible polymer coated by random copolymerization were increased by 136% and 162%, respectively. The composite material of talc powder coated with flexible polymer has obvious strengthening and toughening effect, and can increase strength and toughness continuously and effectively (tensile strength is increased by 1 / 3, impact strength is increased by nearly 2 / 3) in a large range of filling (particle filling mass fraction is 5% - 35%). This kind of composite particle is a new filling material which can effectively improve the comprehensive properties of products and reduce the cost of materials.

4. Modification of talc powder by silane coupling agent

Talcum powder is a kind of polar water-insoluble material. When they are dispersed in the organic polymer resin with very small polarity, because of the difference of polarity, the compatibility of the two is not good, and the direct or excessive filling often leads to some defects of the material, such as the decrease of mechanical properties and the embrittlement, which has a negative impact on the processing and use properties of the products. The surface of talc can be modified by silane coupling agent.

1) Modification method

Prepare silane coupling agent (such as KH-570) into solution, and stir evenly. Drop the solution into the dried talcum powder, stir for 40-60min, make the treatment agent fully cover the filler 4, and then heat and dry to obtain the modified talcum powder.

2) Application characteristics

The talcum powder modified by silane coupling agent can improve the strength and modulus of the filling system, and the effect of modification is good, so it has a good practical application value.

5. Modification of talc phosphate

1) Modification method

Firstly, talcum powder was precoated in the aqueous solution of phosphate ester at 80 ℃ and then dried at 95 ℃; finally, the temperature was raised to 125 ℃ and heat treated for 1 h. The dosage of phosphate is 0.5% - 8% of talc.

2) Application characteristics

The phosphate ester can react with the surface of talc to form the surface coating. Increasing the surface coating amount can improve the dispersion of talc, and can significantly change the morphology and mechanical properties of the filling system.

Shanghai Innovy Chemical New Materials Co., Ltd is ISO9001-2015 certified. We mainly produce and sell chemical raw materials and products such as transparent powder, talcum powder, composite powder, glass powder, calcium carbonate powder, new material for surface treatment powder, and environmentally-friendly coatings, etc. After more than 10 years of development, our company has become a large-scale private chemical raw material supply enterprise integrating production, transportation and sales system.