Method for preparing water-based crylic acid resin by continuous extruding process and production equipment for realizing method

Abstract

The invention provides a method for preparing water-based crylic acid resin by a continuous extruding process and production equipment for realizing the method. The method is characterized in that anannular pipe type reactor and a twin-screw extrusion reactor are connected in series to be used as a continuous reactor; firstly, monomers, initiating agents and optional molecular weight modifiers are sucked into a mixed raw material preparation tank from each raw material barrel under the negative pressure; then, the materials in the preparation tank are conveyed to the annular pipe type reactorwith the temperature being 120 DEG C by a material conveying pump at the speed of 50 to 150kg / h; the detention time of the materials in the annular pipe type reactor is 15 minutes; after the materials enter the twin-screw extrusion reactor, the screw rotating speed is controlled to be 20 to 50 turns / min; a devolatilization section valve is opened so that the materials are subjected to vacuum devolatilization at the third stage; the product after devolatilization is subjected to underwater pelleting and drying at the temperature being 30 DEG C or below, and then passes through a cyclone separator; next, packaging is performed. The crylic acid resin prepared by the method has the characteristics that the quality stability is good; the molecular weight is great; the distribution is narrow. The invention also provides the production equipment for realizing the method.

Description

technical field [0001] The invention relates to a preparation method of acrylic resin, in particular to a preparation method of water-based acrylic resin for water-based varnish, water-based printing ink, water-based wood paint or water-based industrial paint, and more particularly to a continuous extrusion process Method for preparing water-based acrylic resin. The present invention also provides a production device for realizing the above method. Background technique [0002] In 1988, SC Johnson in the United States invented water-based acrylic resin as an emulsifier for water-based varnish emulsion, water-based printing ink emulsion (linker), and a dispersing resin for water-based ink paste. use. Water-based acrylic resin is polymerized from monomers with high gloss and high hardness, styrene, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid or acrylic acid, and the main chain is a strong hydrophobic structure. , the side groups are es...

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Problems solved by technology

[0004] The advantages of the solution polymerization method are: ① The requirements for equipment are not high, and it can be realized by free radical polymerization at atmospheric pressure; ② The molecular weight and its distribution are controlled stably; ③ No special material transfer pump is required; its fatal disadvantage is: when the production scale After exceeding 1500L, how to remove the residual solvent (ethylene glycol or propylene glycol monoether solvent) to less than 1%, if the residual alcohol ether solvent is too large, it is difficult to be used as water-based varnish, water-based printing ink binder— —The emulsifier in the emulsion polymerization process of acrylic copolymer can only be used as the dispersing resin in the process of ink grinding and color paste

[0006] At present, the process of producing water-based acrylic resin by bulk method mainly includes tubular reactor bulk polymerization method and three-pot series continuous bulk polymerization method. The disadvantage of using tubular reactor bulk polymerization method to produce water-based acrylic resin is that the monomer conversion rate must be close to 100. %, so in order to continuously remove the material from the reactor, the temperature of the reactor must be maintained at 270-300°C. Even so, it can only produce water-based acrylic resin with a weight average molecular weight below 10000Da, but cannot produce a weight average molecular weight of more than 10000Da resin, otherwise the material cannot be transported and flowed

The continuous mass polymerization of three reactors in series is the mainstream method at present, but the material transfer pump from the first reactor to the second reactor and the subsequent reactor (third reactor) is very expensive, and the pipeline pump body needs to be treated with temperature. The first disadvantage is that the design pressure of the tank reactor is as high as 7MPa, and the investment in equipment is large; in addition, the biggest disadvantage of the continuous bulk polymerization method with three tanks in series is that it is difficult to control the molecular weight and its distribution, especially in the subsequent tank stage, due to the high viscosity of the system, It is easy to produce auto-acceleration effect, and the addition of initiator and chain transfer agent cannot control this phenomenon, and excellent water-based acrylic resin should have a lower narrow molecular weight distribution, otherwise it will affect the rheological properties and color development of the emulsion binder sex

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