Polyacrylic Acid Resin Polymerization Temperature Control
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Solution Overview
Problem
Existing methods for producing water absorbent resins face challenges in achieving high liquid permeability while maintaining water absorption capacity, often sacrificing other physical properties, and generate significant fine powders that complicate recycling and increase manufacturing costs.
Innovation Solution
A method involving a polymerization process where an aqueous solution of acrylic acid and/or its salt is polymerized in a controlled environment with specific temperature conditions, where the temperature of the liquid contact part (TS) ranges from 35°C to 85°C, the gas temperature (TG) ranges from 40°C to 90°C, and the total temperature (TT) is the average of TS and TG, ranging from 47°C to 73°C, using a polymerization apparatus with a supply line, external gas supply port, and gas discharge port to manage the interaction between the liquid and gas during polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional polymerization methods are used to produce water absorbent resin, then water absorption capacity can be achieved, but liquid permeability deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the polymerization temperature within a specific range (50-70°C) and maintaining a temperature difference of 5-20°C between the polymerization system and gas phase. This temperature parameter control optimizes the polymerization process to produce resin particles with improved liquid permeability while maintaining water absorption capacity, directly resolving the contradiction between these two properties.
2Productivity
If high temperature polymerization is used to improve polymerization rate, then productivity increases, but fine powder generation increases
Solution Approach 1:
The patent changes the temperature parameter from high temperature to a moderate range (50-70°C) and controls the temperature gradient between liquid and gas phases. This parameter optimization maintains sufficient polymerization rate for productivity while significantly reducing fine powder generation during drying and pulverization, resolving the contradiction between productivity and substance loss.
3Device complexity
If temperature control is relaxed in polymerization, then device complexity decreases, but manufacturing precision deteriorates
Solution Approach 1:
The patent establishes specific temperature parameters (50-70°C polymerization temperature, 5-20°C temperature difference with gas phase) that optimize particle formation. By controlling temperature within this optimized range, the patent achieves narrow particle size distribution and high manufacturing precision without requiring excessively complex temperature control systems, resolving the contradiction between device complexity and manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the generation of fine powders and enhances the saline flow conductivity of the water absorbent resin, maintaining excellent absorption properties without compromising water absorption capacity, thereby improving productivity and stability in the manufacturing process.
Implementation Method 1
a polymerization step of supplying as a base material an aqueous solution containing an acrylic acid and/or an acrylic acid salt as a monomer component and polymerizing the monomer in the presence of a polymerization initiator
Implementation Method 2
a structure that a liquid contact part in contact with the aqueous solution and a gas supplied from the outside of the polymerization apparatus are brought into contact with the aqueous solution during a polymerization
Data Source
AI summary
The purpose of the present invention is to provide a method for producing a water absorbent resin having improved physical properties, particularly, improved saline flow conductivity (SFC) and less amount of fine powder. The present invention provides a method for producing a polyacrylic acid (salt)-based water absorbent resin, the method comprising: a polymerization step of supplying as a base material an aqueous solution containing an acrylic acid and/or an acrylic acid salt as a monomer component and polymerizing the monomer in the presence of a polymerization initiator, wherein in the polymerization step, there is used a polymerization apparatus which comprises a polymerization part covered with a case, said polymerization part comprising at least a supply line for supplying the aqueous solution, an external gas supply port, and a gas discharge port, and has a structure that a liquid contact part in contact with the aqueous solution and a gas supplied from the outside of the polymerization apparatus are brought into contact with the aqueous solution during a polymerization, and assuming that a controlled temperature of the liquid contact part is set as TS, a temperature of the gas part is set as TG, and TT is (TS+TG)/2, the polymerization is carried out under temperature conditions satisfying the following Equations 1 to 3:35° C.≦TS≦85° C., Equation 1:40° C.≦TG≦90° C., Equation 2:47° C.≦TT≦73° C. Equation 3: