Dispensing Package Actuator with Segmented Feed Screw
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Solution Overview
Problem
Existing dispensing packages for antiperspirant compositions with high efficacy actives suffer from weeping issues due to residual pressure, which can degrade materials like acetal resin when exposed to hydrochloric acid, leading to inoperability.
Innovation Solution
A dispensing package design featuring an actuator system with a first section made from a polymer with a flexural modulus of 275 ksi to 500 ksi and a second section resistant to acid degradation, allowing the elevator and feed screw to flex and retract, relieving internal pressure and preventing weeping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acetal resin is used to manufacture the feed screw and turn wheel, then sufficient retraction force is provided to prevent weeping, but the material is susceptible to acid degradation from high efficacy actives
Solution Approach 1:
The feed screw is divided into two distinct sections: a first section made from acetal resin that provides the necessary retraction force, and a second section made from acid-resistant material that contacts the antiperspirant composition. This segmentation allows each part to perform its specific function without being compromised by the opposing requirements.
Solution Approach 2:
Different materials are applied to different parts of the feed screw based on local requirements. The portion requiring flexibility and retraction (first section) uses acetal resin, while the portion requiring acid resistance (second section) uses a corrosion-resistant material, optimizing both properties where needed.
2Object-affected harmful factors
If polypropylene is used to manufacture the feed screw, then acid resistance is sufficient, but the flexural modulus is too low to retract the feed screw and elevator to relieve internal pressure
Solution Approach 1:
The feed screw is segmented into two sections with different materials. The first section uses polypropylene or other acid-resistant material to resist degradation from high efficacy actives, while the second section uses material with sufficient flexural modulus to provide the retraction force needed for pressure relief.
Solution Approach 2:
The feed screw is constructed as a composite structure combining materials with different properties. The composite design integrates acid-resistant material with flexible material to achieve both chemical resistance and mechanical flexibility in a single component.
3Ease of manufacture
If a one-piece turn wheel and feed screw design is used, then manufacturing is simplified, but the entire structure must compromise between flexural modulus and acid resistance
Solution Approach 1:
The monolithic structure is segmented into multiple sections with different materials, allowing each section to be optimized for its specific function while maintaining ease of manufacture through techniques like co-molding or overmolding.
Solution Approach 2:
Instead of using a uniform material throughout the entire turn wheel and feed screw assembly, local quality optimization is applied by using different materials in different regions, allowing the structure to simultaneously achieve both manufacturing efficiency and property optimization.
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 effectively prevents weeping and maintains package functionality even when exposed to antiperspirant actives that generate hydrochloric acid, ensuring reliable dispensing of high efficacy antiperspirant compositions.
Implementation Method 1
a first section that flexes towards the applicator surface during advancement of the elevator and then rebounds away from the applicator surface to retract the elevator
Data Source
AI summary
Dispensing packages are disclosed that are capable of dispensing soft-solid type antiperspirant compositions employing actives having a metal to chloride ratio of less than or equal to 1.3, and that are capable of exhibiting minimal weeping in between uses.