Preparation of efficient ground calcium carbonate grinding dispersant by photo-initiating room-temperature RAFT (Reversible Additive Fragment Transfer) polymerization

A technology of photoinitiator and dispersant, applied in the field of high-efficiency grinding dispersant and preparation, can solve problems such as precipitation and lower utilization efficiency of dispersant, and achieve the effects of narrow molecular weight distribution, controllable molecular weight and low energy consumption

Inactive Publication Date: 2014-09-10
DSSUN NEW MATERIAL SHANDONG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The research results of J.Loiseau [Macromolecules 2003,36,3066-3077] show that polydisperse sodium polyacrylate close to the molecular weight has better dispersion than polydisperse sodium polyacrylate, and the former can be irreversibly adsorbed to calcium carbonate particles completely On the surface of calcium carbonate, so as to achieve a good dispersion of calcium carbonate; while the latter can only be partially selectively adsorbed on the surface of calcium carbonate particles, the utilization efficiency of the dispersant is greatly reduced, and precipitation will occur

Method used

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  • Preparation of efficient ground calcium carbonate grinding dispersant by photo-initiating room-temperature RAFT (Reversible Additive Fragment Transfer) polymerization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Preparation of sodium polyacrylate with low molecular weight and narrow distribution:

[0024] Add 11.16 g of dithioester chain transfer agent 4-cyano-4-dithiobenzoyloxyvaleric acid, photoinitiator 2,4,6-trimethylbenzoyl-di 7.00 g of phenylphosphine oxide, 355.0 g of toluene as a solvent, and 256.59 g of tert-butyl acrylate as a monomer. The system was bubbled with nitrogen for 20 minutes and then sealed. During the bubbling process, avoid light. The reactor should be wrapped with aluminum foil, and then placed under an ultraviolet lamp with a central wavelength of 365nm. The ultraviolet light is irradiated by a cut-off plate with a cut-off wavelength greater than 254nm, while maintaining the incident intensity of ultraviolet light at 10mw / cm 2 , Remove the aluminum foil at room temperature and start to react for 8 hours. After the completion, the obtained solution was mixed with 61.17 g of sodium hydroxide solution (32%) and then heated and hydrolyzed for 3 hours to ...

Embodiment 2

[0026] Preparation of sodium polymethacrylate with low molecular weight and narrow distribution:

[0027] Add 9.47g of dithioester chain transfer agent cyanoisopropyl dithiobenzoate and 7.49g of photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide in the quartz reaction vessel, Solvent toluene 248.54g and monomer t-butyl methacrylate 213.00g. The system was bubbled with nitrogen for 20 minutes and then sealed. During the bubbling process, avoid light. The reactor should be wrapped with aluminum foil, and then placed under an ultraviolet lamp with a central wavelength of 365nm. The ultraviolet light is irradiated by a cut-off plate with a cut-off wavelength greater than 254nm, while maintaining the incident intensity of ultraviolet light at 10mw / cm 2 , Remove the aluminum foil at room temperature and start to react for 6 hours. After the completion, the obtained solution was mixed with 42.00 g of sodium hydroxide solution (32%) and then heated and hydrolyzed for 3 ho...

Embodiment 3

[0029] Preparation of low molecular weight narrow distribution poly(sodium acrylate-co-sodium methacrylate):

[0030] Add trithioester chain transfer agent 2-(dodecyltrithiocarbonate group)-2-methylpropionic acid 18.21g in quartz reaction vessel, photoinitiator benzophenone 4.55g, solvent toluene 351.24 g and the monomers tert-butyl methacrylate 142.20 g and tert-butyl acrylate 128.23 g. The system was bubbled with nitrogen for 20 minutes and then sealed. During the bubbling process, avoid light. The reactor should be wrapped with aluminum foil, and then placed under an ultraviolet lamp with a central wavelength of 365nm. The ultraviolet light is irradiated by a cut-off plate with a cut-off wavelength greater than 254nm, while maintaining the incident intensity of ultraviolet light at 12mw / cm 2 , Remove the aluminum foil at room temperature and start to react for 8 hours. After the end, the resulting solution was mixed with 59.41 g of sodium hydroxide solution (32%) and then...

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Abstract

The invention discloses a preparation method of an efficient ground calcium carbonate grinding dispersant by photo-initiating room-temperature RAFT (Reversible Additive Fragment Transfer) polymerization. The method comprises the following steps: adding a vinyl carboxylic ester monomer, a polythio ester chain transfer agent and a photoinitiator into a solvent and bubbling for 15-30 minutes by nitrogen; illuminating to react for 3-12 hours by an ultraviolet lamp, wherein the central wavelength of the ultraviolet lamp is 365nm and incident light passes through a wave cutoff sheet with the wave cutoff range greater than 254nm; after reaction, mixing the obtained solution with an NaOH solution, hydrolyzing for 3-10 hours at 80-120 DEG C, carrying out reduced pressure distilling to remove the solvent and alcohol byproducts, then, adding the NaOH solution to adjust the pH to 4-8 and adding water to adjust the solid content to 41-43% to obtain the efficient ground calcium carbonate grinding dispersant. Compared with conventional free radical polymerization, the method has the advantages of controllable molecular weight, narrow distribution of molecular weight and no free countra-ions introduced in the initiating process. The method has the following characteristics of simple treatment, pure product and low energy consumption and meets modern green chemistry.

Description

technical field [0001] The invention relates to a high-efficiency grinding dispersant and a preparation method. Background technique [0002] Dispersants play a very important role in the wet grinding production of ultra-fine heavy calcium, which can significantly reduce the grinding viscosity of heavy calcium materials, reduce anti-sticking after grinding, and increase the stability of slurry, which is very important for reducing wear and improving product quality. have an important role. [0003] At present, most of the dispersants for heavy calcium grinding are polycarboxylate aqueous solutions, and the main synthesis method is traditional solution free radical polymerization. However, the molecular weight distribution of polymers synthesized by traditional solution free radical polymerization is very wide, and the molecular weight control is poor. According to research, the molecular weight and distribution of dispersant have a great influence on its dispersion effect....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F120/16C08F2/38C08F2/48C08F8/12C08F220/16B01F17/52C09K23/52
Inventor 施晓旦邵威金霞朝
Owner DSSUN NEW MATERIAL SHANDONG
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