Water-Soluble Laundry Sheet Foamability and Stiffness Control
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Solution Overview
Problem
Water-soluble laundry sheets are prone to smashing during manufacture and are difficult to cut into desired sizes due to their hardness or softness, affecting their solubility and usability.
Innovation Solution
A laundry sheet with a water-soluble polymer, such as polyvinyl alcohol, is formulated to have specific foamability and drape stiffness ranges (0.5-0.9 g/cm3 and 3.5-7.5 cm) to prevent smashing and facilitate easy cutting, using additives like surfactants and controlling glass transition temperature to enhance solubility and tearability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the laundry sheet is made too hard to prevent smashing, then it becomes difficult to cut into desired sizes and transport
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) of the water-soluble polymer within 56-75°C and adjusting foamability to 0.5-0.9 g/cm³. These parameter adjustments optimize the balance between sheet hardness (to prevent smashing) and cuttability (for ease of operation), resolving the technical contradiction between strength and ease of cutting.
2Ease of operation
If the laundry sheet is made too soft to allow easy cutting, then it becomes prone to smashing during manufacture and distribution
Solution Approach 1:
The patent resolves this contradiction by changing the physical parameters of the polymer matrix, specifically controlling the glass transition temperature within 56-75°C and foamability within 0.5-0.9 g/cm³. These parameter changes enable the sheet to have optimal softness for cutting while maintaining sufficient hardness to resist smashing during manufacture and distribution.
3Reliability
If water-soluble polymer films are designed to have stability against moisture and durability, then they require significantly long time for dissolution at low temperature and cannot dissolve completely
Solution Approach 1:
The patent applies parameter changes by controlling the glass transition temperature of the water-soluble polymer within 56-75°C. This specific Tg range optimizes the polymer's water solubility and dissolution kinetics, enabling the film to maintain moisture stability during storage while dissolving completely and quickly at low temperatures, thus resolving the contradiction between reliability and dissolution time.
Solution Approach 2:
The patent uses composite materials by combining the water-soluble polymer with a foaming agent to create a foam structure with controlled foamability (0.5-0.9 g/cm³). This composite structure increases the surface area and porosity of the film, accelerating water penetration and dissolution while maintaining structural integrity and moisture stability during storage.
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 laundry sheet achieves excellent solubility and ease of cutting, ensuring effective washing performance and user convenience without leaving residue.
Implementation Method 1
a water-soluble laundry sheet including a detergent ingredient dispersed in a polymer matrix formed from a water-soluble film and providing a cleaning effect while the detergent ingredient is dissolved in water
Implementation Method 2
the laundry sheet may have (i) a foamability of 0.5-0.9 (g/cm3) or (ii) a drape stiffness of 3.5-7.5 cm
Data Source
AI summary
The present invention provides a laundry sheet in which at least one laundry component is distributed inside a matrix formed from a water-soluble polymer, which is a polyvinyl alcohol or a polyvinyl alcohol-based polymer, and the laundry sheet has (i) a foamability of 0.5-0.9 (g/cm3) or (ii) a drape stiffness of 3.5-7.5 cm.