Two-Shot Molded Seal for Personal Care Applicators
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Solution Overview
Problem
Existing applicators for solid and gel antiperspirant/deodorant compositions face challenges in providing effective sealing and retention due to the relative lack of stiffness in gel products, leading to inefficient dispensing and user experience issues.
Innovation Solution
A two-shot molded seal comprising a rigid structural element and a soft, flexible sealing element, where the soft sealing element is overmolded onto the structural element, providing enhanced engagement and retention with the barrel surface, and includes a dome and flange design for improved sealing and user-friendly removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid seal is used for gel compositions, then structural support is provided, but sealing effectiveness deteriorates due to lack of compliance with the barrel surface
Solution Approach 1:
The seal is constructed as a composite structure with a rigid structural element (polypropylene) providing strength and support, and a soft sealing element (thermoplastic elastomer) providing compliance and sealing effectiveness. The two materials are overmolded together to create a unified component that delivers both structural integrity and reliable sealing against the barrel surface.
Solution Approach 2:
Different regions of the seal have different material properties: the structural element provides rigidity where support is needed, while the sealing element provides softness and compliance where contact with the barrel surface occurs. This local differentiation of material quality allows the seal to simultaneously achieve structural support and effective sealing.
2Reliability
If a soft sealing element is used, then sealing effectiveness is improved, but structural support deteriorates
Solution Approach 1:
The seal combines a soft thermoplastic elastomer sealing element with a rigid polypropylene structural element. The soft material provides compliance and sealing effectiveness, while the rigid material provides structural support and maintains the seal's shape and position within the applicator.
Solution Approach 2:
The seal is divided into two functional segments: a sealing element that contacts the barrel surface and a structural element that provides support and maintains geometry. These segments are integrated through overmolding to form a single component that delivers both soft sealing and rigid structural support.
3Ease of operation
If a removable seal is used, then ease of removal is improved, but retention during storage deteriorates
Solution Approach 1:
The seal's engagement with the applicator is designed to be dynamic rather than static: during storage and transport, the seal remains securely retained through friction and geometric engagement; during use, the user can easily remove it by applying minimal force to break the engagement. The design allows the seal to transition between a retained state and a removable state.
Solution Approach 2:
The seal is pre-configured with features such as a flange and specific engagement geometry that enable easy removal by the user while maintaining strong retention during storage. The preliminary design of the engagement mechanism ensures that removal requires simple user action without tools or complex operations.
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 enhances sealing and retention, improving the dispensing process and user experience by utilizing the compliance and stiction of the soft sealing element, while allowing for easy removal and ergonomic design.
Implementation Method 1
utilizing the compliance and stiction of the soft sealing element
Implementation Method 2
providing enhanced engagement and retention with the barrel surface
Implementation Method 3
the soft sealing element is overmolded onto the structural element
Data Source
AI summary
A personal care applicator apparatus seal has a structural element formed of a first material and a sealing element formed of a second material softer or less rigid than the first material. The structural element may have a sidewall with upper and lower ends and inboard and outboard surfaces. The sealing element may be molded to the structural element and may include a first portion circumscribing the sidewall.