Absorbent Article Oxidative Decomposer Biodegradability
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Solution Overview
Problem
Biodegradable absorbent articles using hydrolyzable resins suffer from lower molding workability and strength compared to petroleum-based resins, leading to inferior properties and prolonged decomposition, which increases environmental load at landfills.
Innovation Solution
Incorporating an oxidative decomposer made of a mixture of a carboxylate and a rare earth compound into synthetic resin sheets, along with an oxidative decomposition accelerator like sodium percarbonate or hydrogen peroxide, to control the decomposition rate and ensure rapid disintegration after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If hydrolyzable biodegradable resins are used to form structural members, then biodegradability is improved, but strength and durability deteriorate
Solution Approach 1:
The patent divides the decomposition process into two distinct phases: a first phase using hydrolyzable biodegradable resins that decompose relatively slowly to maintain strength during use, and a second phase using non-hydrolyzable biodegradable resins that decompose rapidly after use. This segmentation allows each resin type to perform its specific function optimally without compromising the other.
Solution Approach 2:
The patent creates a composite material system by combining hydrolyzable biodegradable resins (first structural members) with non-hydrolyzable biodegradable resins (second structural members). This composite structure enables the material to exhibit both long-term durability during use and rapid decomposition after disposal, resolving the contradiction between strength and biodegradability.
2Ease of manufacture
If general purpose synthetic resins are mixed with hydrolyzable biodegradable resins, then molding workability is improved, but decomposition rate deteriorates
Solution Approach 1:
The patent extracts the general purpose synthetic resin from the mixture and replaces it with non-hydrolyzable biodegradable resins. This extraction eliminates the problem of slow decomposition while maintaining the molding workability benefits, as the non-hydrolyzable biodegradable resins can be processed similarly to conventional synthetic resins.
Solution Approach 2:
The patent changes the chemical parameter of the resin from hydrolyzable to non-hydrolyzable, which fundamentally alters the decomposition behavior. Non-hydrolyzable biodegradable resins maintain synthetic resin-like processing characteristics while enabling faster decomposition through alternative degradation mechanisms, thus improving decomposition rate without sacrificing molding workability.
3Productivity
If oxidative decomposers are added to synthetic resin sheets, then decomposition rate is improved, but premature decomposition during use may occur
Solution Approach 1:
The patent incorporates oxidative decomposers and accelerators into the structural members during manufacturing, but designs the system so that these components remain dormant during use. The preliminary action is prepared in advance, but the actual decomposition acceleration only occurs after use when water activates the system, preventing premature decomposition while ensuring rapid breakdown when needed.
Solution Approach 2:
The patent introduces water as an intermediary that triggers the decomposition process. Water-sensitive capsules containing oxidative accelerators remain stable during use but activate upon contact with water (such as urine in the case of diapers), releasing the accelerators to trigger rapid decomposition. This intermediary mechanism ensures timing control, preventing premature decomposition while enabling fast breakdown after disposal.
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
Maintains the properties of conventional synthetic resin-based absorbent articles for extended use while ensuring rapid disintegration post-use, thereby reducing environmental impact.
Implementation Method 1
the synthetic resin sheet that includes an oxidative decomposer... oxidative decomposition of the synthetic resin sheet by the oxidative decomposer
Implementation Method 2
an oxidative decomposition accelerator composed of a peroxide... oxidative decomposition accelerator can reach the oxidative decomposer in the synthetic resin sheet... oxidative decomposition of the synthetic resin sheet by the oxidative decomposer can be accelerated
Implementation Method 3
inside water-sensitive capsules in the absorbent body... making it possible to inhibit activation of the accelerating function of the oxidative decomposition accelerator
Data Source
AI summary
An absorbent article may include a top sheet that is liquid-permeable, a back sheet that is liquid-impermeable, and an absorbent body situated between the top sheet and the back sheet in a thickness direction. At least one of the top sheet and the back sheet may include a synthetic resin sheet that includes a synthetic resin component and an oxidative decomposer comprising a mixture of a carboxylate and a rare earth compound. The synthetic resin sheet may contain the oxidative decomposer in a mass ratio such that a decomposition rate index (Di), as determined by formula (1), is 7.8 or less:Di=Br×Sa (1)where Br represents a mass ratio (g/g) of the oxidative decomposer with respect to the synthetic resin component, and Sa represents a specific surface area (cm2/g) of the synthetic resin sheet.