1. Silane coupling agent KH570 modified nano calcium carbonate Conditions: The amount of silane coupling agent KH570 was 5%, the modification temperature was 70 ° C, and the time was 2 h. Effect: The silane coupling agent has been successfully grafted onto the surface of nano-CaCO3. The maximum grafting ratio of KH570 in modified nano-CaCO3 is 1.5%, the maximum grafting efficiency is 36.7%; the surface polarity of nano-CaCO3 is decreased. The lipophilicity is greatly increased and the particle dispersibility is significantly improved. A-unmodified nano calcium carbonate, b-5%KH570 modified nano calcium carbonate 2, sodium stearate modified light calcium carbonate Conditions: 3% sodium stearate (calcium carbonate mass) was added during the digestion, the digestion temperature was 80 ° C, the pH was 14, and the aging time was 30 min. Effect: Sodium stearate is bonded to the surface of light calcium carbonate by ion bonding. The activation degree of modified calcium carbonate can reach 97.1%. 3. Titanate coupling agent modified light calcium carbonate Conditions: The amount of titanate coupling agent was 2%, the modification temperature was 80 ° C, and the modification time was 1 h. Effect: The titanate coupling agent is hydrogen-bonded with calcium carbonate. The modified calcium carbonate has a degree of activation of up to 95%. It can be well dispersed in liquid paraffin, and the deposition rate and apparent viscosity are significantly reduced. 4, aluminate coupling agent modified heavy calcium carbonate Conditions: The amount of the aluminate coupling agent was 1.5%, the modification temperature was 110 ° C, and the modification time was 12 min. Effect: The contact angle of heavy calcium carbonate modified by aluminate coupling agent can reach 162.4°, and the lipophilicity is obviously improved. The modified calcium carbonate is filled with polybutene-1 material, and the dispersion is better in the matrix. It has strong bonding ability with polybutene-1 and can absorb deformation work and improve the toughness of composite materials. A-pure polybutene-1 material, b-unmodified heavy calcium carbonate filled polybutene-1 material, c-aluminate coupling agent modified heavy calcium carbonate filled polybutene- 1 material 5, polyether coupling agent modified light calcium carbonate Conditions: The coupling agent tetrahydrofuran homopolyether (PTHF) is used in an amount of 2% to 3%, the modification temperature is 70-80 ° C, and the modification time is 1 h. Effect: Tetrahydrofuran homopolyether can reduce the oil absorption of calcium carbonate to 22% and the contact angle to 68.6°. The modified calcium carbonate is filled into the polypropylene, which can alleviate the downward trend of the tensile strength to a certain extent, so that the elongation at break of the composite material reaches 28.47% and the impact strength reaches 6.7 kJ/m2. 6, phosphate ester surfactant ADDP modified nano calcium carbonate Conditions: The amount of ADDP is 2%, the modification temperature is 50 °C, and the modification time is 30 min. Effect: The surface of the modified nano-calcium carbonate is hydrophobic and oleophilic, the average agglomerated particle size in the oil is reduced, and the oil absorption value, viscosity and surface energy are all significantly reduced. After the modified nano calcium carbonate was filled in the soft PVC, the processing performance of the system was obviously improved; the mechanical properties of the composite system were also improved to some extent. 7. Hydrous acid anhydride modified heavy calcium carbonate Conditions: The amount of the acid anhydride hydrolyzate was 1.5%, the modification temperature was 50 ° C, and the modification time was 15 min. Effect: The activated heavy calcium carbonate activation degree can reach 83.40%, the oil absorption value is reduced to 28.29mL/100g, the viscosity is reduced by 46.36%, and the water contact angle is 99°. The modified calcium carbonate is filled into the PVC material, which can play a toughening effect, so that the notched impact strength of the composite increases from 8.46 kJ/m2 to 10.21 kJ/m2, and the elongation at break increases from 16.12% to 24.52%. 8. Starch-stearic acid complex modified light calcium carbonate Conditions: The amount of starch used was 20%, the stirring time was 20 min, the reaction temperature was 40 ° C, the starch concentration was 3.0%, and the amount of fatty acid was 4.0%. Effect: The surface of the modified light calcium carbonate is coated with starch, the surface becomes smooth and the edges and corners are not obvious; under the same filling amount, the paper filled with modified calcium carbonate and the unfilled unmodified calcium carbonate and the traditional process Good performance compared to filled paper. 9, aluminate coupling agent, stearic acid as modified light calcium carbonate Conditions: the aluminate content was 1.0%, the stearic acid content was 0.8%, the stirring speed was 650 r/min, and the reaction temperature was 100 °C. Effect: The contact angle of modified light calcium carbonate with water can reach 136.5°, and it is easy to disperse in oily medium; the modified calcium carbonate has good wettability with polyethylene, and can avoid filler during processing. The polar surface is exposed under the action of high temperature and high shear force, which causes disadvantages such as poor rheology and difficulty in processing. Contact angle test results of calcium carbonate and water: a-modified calcium carbonate, b-unmodified calcium carbonate 10, double layer coupling agent modified calcium carbonate Conditions: The amount of the silane coupling agent KH560 is 0.5%, the amount of the titanate coupling agent 102 is 0.5%, the modification temperature is 120 ° C, and the modification is dry. Effect: Si-OH with silane coupling agent KH560 as inner layer can form hydrogen bond with OH- on the surface of calcium carbonate, and the epoxy bond at the end of KH560 and the monoalkoxy group of titanate coupling agent are opened. The reaction forms a chemical structure to form a thick double-layer coating structure on the surface of the calcium carbonate; the modified calcium carbonate is filled with PBAT resin at 50% to prepare a composite material having a tensile strength of 20.28 MPa, compared to the unmodified composite material. The tensile strength was increased by 39%, and the tensile strength of the composite prepared by the surface modification technique of the single layer KH560 and titanate 102 was increased by 16.8% and 26.6%, respectively. Australia Temporary Fence,Mobile Temporary Fence,Portable Fencing,Portable Temporary Fence Hebei Haiao Wire Mesh Products Co., Ltd. , https://www.haiaowiremeshfencing.com
10 cases of calcium carbonate surface modification
Surface modification is an important means to improve the application performance, improve applicability, expand market and dosage of calcium carbonate. In the future, functionalization and specialization will become the main trend of calcium carbonate development, and the market demand for various surface modification special calcium carbonate. The amount will be bigger and bigger.