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Preparation method of special nano calcium carbonate for rubber

A nano-calcium carbonate and calcium carbonate technology, applied in the direction of calcium carbonate/strontium/barium, etc., can solve the problems of affecting the use effect and poor dispersibility, and achieve the effects of reducing oil absorption value, improving strength and improving dispersibility.

Inactive Publication Date: 2019-06-21
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is recognized that chain-like nano-calcium carbonate has a good reinforcing effect in rubber, but due to poor dispersion, it cannot be well compatible with rubber compounds, which affects the use effect

Method used

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  • Preparation method of special nano calcium carbonate for rubber

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031]Limestone of 4-8cm is selected and calcined in a mechanical shaft kiln. The calcining temperature is controlled at 950-1150°C for 12 hours to obtain active lime (CaO). The active lime (CaO) is digested by adding hot water at 45°C. The gray-water ratio is 1:5, and the coarse lime milk concentration is 14.50%. The digested coarse pulp is aged at 40-60°C for 24 hours, and then subjected to hydrocyclone separation and screening to obtain a refined emulsion for aging; the Ca(OH) is adjusted by adding water and heat exchange 2 The emulsion concentration is 10.5%, Ca(OH) 2 The temperature of the emulsion is 25°C, add sodium polyacrylate to the milk of lime, the molecular weight is 4000-5000, the dosage is 0.2%, after stirring evenly, add 0.5% of crystal form control agent sodium citrate and 0.5% of aluminum chloride, pump into 30m 3 Reactor, while feeding CO 2 Concentration of 28% kiln gas, kiln gas flow rate is 30m 3 / min; when reacting to PH=8, add water glass with a modul...

Embodiment 2

[0033] Select 8-12cm limestone and calcinate it in a mechanical shaft kiln. Control the calcining temperature at 950-1150°C for 24 hours to obtain active lime (CaO). The active lime (CaO) is digested by adding hot water at 50°C. The ratio of lime:water is 1:5.5, resulting in a crude milk of lime with a concentration of 13%. The digested coarse pulp is aged at 40-60°C for 12 hours, and then subjected to hydrocyclone separation and screening to obtain a refined emulsion for aging; the Ca(OH) is adjusted by adding water and heat exchange 2 Emulsion is 9.5%, Ca(OH) 2 The temperature of the emulsion is 22°C, add sodium polyacrylate into the lime milk, the molecular weight is 4000-5000, the dosage is 0.25%, after stirring evenly, then add the crystal form control agent sodium citrate 0.6%, EDTA-2Na0. Into 30m 3 Reactor, while feeding CO 2 Concentration of 30% kiln gas, kiln gas flow rate is 30m 3 / min; when reacting to PH=8.5, add water glass with a modulus of 2.8, add 5% accord...

Embodiment 3

[0035] Select 8-12cm limestone and calcinate it in a mechanical shaft kiln. Control the calcining temperature at 950-1150°C for 24 hours to obtain active lime (CaO). The active lime (CaO) is digested by adding hot water at 50°C. The ratio of lime:water is 1:5.5, resulting in a crude milk of lime with a concentration of 16%. The digested coarse pulp is aged at 40-60°C for 18 hours, and then subjected to hydrocyclone separation and sieving to obtain a refined emulsion for aging; adjust the Ca(OH) by adding water and exchanging heat 2 Emulsion is 9%, Ca(OH) 2 The temperature of the emulsion is 21°C, add sodium polyacrylate into the milk of lime, the molecular weight is 4000-5000, the dosage is 0.2%, after stirring evenly, add the crystal form control agent sodium citrate 0.6%, aluminum sulfate 1.0%, etc., pump Into 30m 3 Reactor, while feeding CO 2 Concentration of 30% kiln gas, kiln gas flow rate is 30m 3 / min; When the reaction reaches PH=8, add methyl silicate, add 3.5% ac...

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Abstract

The invention discloses a preparation method of pecial nano calcium carbonate for rubber. The method comprises the following main steps: controlling lime roasting temperature, slaking lime and water ratio, slaking temperature and concentrated slurry ageing time so as to obtain active lime milk for producing nano calcium carbonate; controlling the carbonizing starting temperature and concentrationof the lime milk; adding a special dispersing agent and a crystal form controlling agent for carbonizing at the beginning of feeding in a tower so at o obtain special chain-shaped nano calcium carbonate particles; adding a silicon source in the later period of carbonizing or after carbonizing; controlling the calcium carbonate slurry at the temperature of 60-70 DEG C; adding a surfactant for processing; dewatering and drying the processed slurry until the water content is less than 0.5%; depolymerizing to obtain a primary modified dry nano calcium carbonate powder; feeding into a high-speed mixer; processing through a coupling agent; and depolymerizing again to obtain the composite modified nano calcium carbonate. The prepared nano calcium carbonate is high in dispersing performance, highin compatibility with a rubber base material, and high in mechanical performance, and can be used as an outstanding reinforcing filler of the rubber.

Description

technical field [0001] The invention relates to the field of ultrafine inorganic powder manufacturing, and more specifically relates to a method for preparing nano-calcium carbonate special for rubber. Background technique [0002] Calcium carbonate is widely used as a filler in plastics, rubber, paint, paper and other industries because of its high quality and low price. With the development of science and technology, the demand for rubber products in all walks of life continues to expand, but the quality requirements are also more stringent. At present, carbon black and white carbon black are generally used as the main reinforcing agent for rubber products, and heavy calcium and ordinary light calcium are used as fillers. [0003] Some manufacturers also use a small amount of nano-calcium carbonate to replace carbon black and white carbon black. Although progress has been made, the effect is mediocre and there is still a lot of room for improvement. [0004] In recent ye...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/18C08L9/06C08K13/06C08K9/10C08K9/06C08K3/26
Inventor 匡尹杰向枫涂敏周琼花陈敏李宇春
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY