Absorbent Resin Particle with Dynamic Absorption Rate Pattern

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional absorbent resin particles in absorbent articles, such as disposable diapers, exhibit uneven absorption ratios leading to skin irritation due to inappropriate absorption rate patterns, where the absorption rate is either too rapid or too slow, resulting in unabsorbed liquid remaining on the skin.

Innovation Solution

Development of an absorbent resin particle with a specific absorption rate pattern characterized by a slow initial absorption, moderate middle-stage absorption, and fast late-stage absorption, achieved by incorporating a crosslinked polymer with water-soluble and hydrolyzable vinyl monomers and a crosslinking agent, and combining it with a fibrous material in an absorber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If an absorbent resin particle with fast initial absorption is used, then absorption rate in early stage is improved, but absorption uniformity deteriorates and liquid remains on skin

Engineering Contradiction:

Improveabsorption rate in early stageVSAvoidabsorption uniformity

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The invention changes the absorption rate parameter over time by controlling the swelling behavior of the hydrogel. By adjusting the crosslinking density and composition of the crosslinked polymer, the particle exhibits slow initial absorption (avoiding gel formation that blocks diffusion) followed by accelerated absorption in later stages, achieving both high speed and uniformity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention makes the absorption characteristics dynamic rather than static. The absorbent resin particle transitions from a slow absorption state in the early stage to a fast absorption state in the late stage. This dynamic behavior ensures uniform liquid distribution across the absorber while maintaining high overall absorption rate

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If an absorbent resin particle with slow absorption is used, then absorption uniformity is improved, but absorption rate deteriorates and liquid stays on skin longer

Engineering Contradiction:

Improveabsorption uniformityVSAvoidabsorption rate

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The invention implements periodic action in the absorption process. The absorbent resin particle exhibits slow absorption in the early stage (first period), then transitions to fast absorption in the late stage (second period). This periodic behavior pattern ensures both uniformity and high overall absorption rate, preventing liquid from remaining on skin

Inventive Principle:

Principle #19Periodic action

3Ease of manufacture

If conventional absorbent resin particles are used, then production cost is reduced, but skin irritation occurs due to unabsorbed liquid

Engineering Contradiction:

Improveproduction costVSAvoidskin irritation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention uses composite materials by combining a crosslinked polymer matrix with hydrogel components. This composite structure enables the unique absorption rate pattern (slow initial, fast later) that prevents liquid accumulation and skin irritation while maintaining cost-effectiveness through efficient material utilization

Inventive Principle:

Principle #40Composite materials

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 absorbent resin particle ensures uniform absorption performance across the article, reducing skin irritation and enhancing the overall absorption efficiency, as evidenced by the sigmoid absorption rate curve and improved water-retention properties.

Implementation Method 1

an absorbent resin particle having a structure wherein a hydrophobic substance is contained in the inside of a crosslinked polymer

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

when the absorbent resin particle absorbs the liquid and swells to become a gel form

Methodology Applied

Scientific EffectSwelling: Hydrogel

Implementation Method 3

attaching a hydrophobic substance on the surface of a crosslinked polymer

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 4

a crosslinked polymer (A1) including, as an essential constituent unit, a water-soluble vinyl monomer (a1) and/or a hydrolyzable vinyl monomer (a2)

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentUS8742023B2Absorbent resin particle, process for producing the same, absorber containing the same, and absorbent article

Publication Date: 2014.06.03 NANTONG JIANGTIAN CHEM CO LTD

AI summary

There is provided an absorbent resin particle having an absorption rate pattern where the rate is slow in the initial stage, moderate in the middle stage, and fast in the late stage, and there is also provided an absorbent article free from problems such as skin irritation by using the absorbent resin particle.The present invention relates to an absorbent resin particle comprising a crosslinked polymer (A1) including, as an essential constituent unit, a water-soluble vinyl monomer (a1) and/or a hydrolyzable vinyl monomer (a2), and a crosslinking agent (b),wherein, in a measurement method of swelled volume per 1 g of the absorbent resin particle against physiological saline, a ratio (t2/t1) of the time (t2) until swelled volume reaches 40 ml to the time (t1) until the swelled volume reaches 5 ml is 5 to 20.