Water-absorbing agent feed rate stability
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Solution Overview
Problem
Water-absorbing agents exhibit unstable feed rates when fed using certain feeders, such as BSP-type apparatuses, due to changes in temperature and humidity, and existing indicators like Carr's flowability index are not effective in predicting feed rate fluctuations.
Innovation Solution
A water-absorbing agent with specific properties, including a polyacrylic acid-based resin, a polyvalent metal salt, and controlled particle size distribution, is developed to stabilize feed rates by using a correlation equation that considers bulk density, compressibility rate, and angle of repose, ensuring a high K-index and low moisture absorption blocking ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a BSP-type apparatus is used to feed water-absorbing agent, then the feed rate can be controlled, but the feed rate becomes unstable due to temperature and humidity changes
Solution Approach 1:
The patent modifies the physical parameters of the water-absorbing agent by controlling particle size distribution (D50: 200-600 μm, σ: 0.20-0.50) and adding specific additives (polyvalent metal salts, waxes, oils) to change the material's bulk density, compressibility rate, and angle of repose, making the feed rate stable despite temperature and humidity variations
Solution Approach 2:
The patent introduces new evaluation parameters (K-index, moisture absorption blocking ratio, bulk density, compressibility rate, angle of repose) that provide feedback on the water-absorbing agent's properties, allowing optimization of the material to ensure stable feeding with BSP-type apparatus
2Measurement precision
If Carr's flowability index is used to predict feed rate stability, then flowability can be assessed, but it fails to predict feed rate fluctuations for BSP-type apparatus
Solution Approach 1:
The patent extracts the limitations of Carr's flowability index for BSP-type apparatus feeding and introduces new evaluation parameters (K-index, moisture absorption blocking ratio, bulk density, compressibility rate, angle of repose) that are specifically relevant to positive displacement pumping, providing accurate prediction of feed rate stability
Solution Approach 2:
The patent changes the evaluation parameters from Carr's flowability index to a new set of parameters (K-index, moisture absorption blocking ratio, bulk density, compressibility rate, angle of repose) that are specifically suited for assessing feed rate stability with BSP-type apparatus
3Adaptability or versatility
If water-absorbing agent particles aggregate due to temperature and humidity changes, then the material adapts to environmental conditions, but the feed rate becomes unstable
Solution Approach 1:
The patent converts the harmful effect of temperature and humidity changes (which cause aggregation and adhesion) into a beneficial outcome by adding specific additives (polyvalent metal salts, waxes, oils) that control moisture absorption and reduce adhesion, allowing the material to adapt to environmental changes while maintaining stable feed rate
Solution Approach 2:
The patent creates a composite water-absorbing agent material by combining polyacrylic acid-based resin with specific additives (polyvalent metal salts, waxes, oils) to produce a material with controlled bulk density, compressibility rate, and angle of repose that maintains feed rate stability across varying environmental conditions
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
The solution provides a stable and accurate feed rate with minimal fluctuations, even under varying conditions, enhancing the reliability of water-absorbing agents in absorbent articles.
Implementation Method 1
Water-absorbing resin (Super Absorbent Polymer, or SAP) is a water-swellable, water-insoluble polymer gelling agent
Implementation Method 2
Water-absorbing resin is a water-swellable, water-insoluble polymer gelling agent
Data Source
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AI summary
Provided is a water-absorbing agent that causes no or little fluctuation of feed rate when fed with use of a feeder. A water-absorbing agent containing a water-absorbing resin as a main component, the water-absorbing agent satisfying the following (a) and (b): (a) K-index is 70 or more; and (b) Moisture absorption blocking ratio, after 30 minutes of standing at a temperature of 25°C and a relative humidity of 80%RH, is 70 weight% or less, the K-index being defined by the following equation: K-index = 100 - (-438 + 3.6 x angle of repose + 3.5 x angle of difference + 7.9 x compressibility rate + 290 x bulk density (EDANA method)).