Mono-Material Dropper Container With Interference-Fit Sealing

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Solution Overview

Problem

Dropper bottles in cosmetic packaging require disassembly of components made from different materials for recycling, which is inconvenient.

Innovation Solution

The dropper container is designed with a bulb, dropper base, outer cap, and inner plug made from the same plastic material, utilizing interference fits and convex rings for assembly and sealing, eliminating the need for disassembly during recycling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the bulb, dropper, and outer cap are made of different materials, then each component can be optimized for its specific function, but the dropper cap needs to be disassembled for recycling, which is inconvenient

Engineering Contradiction:
Improvefunctional optimizationVSAvoidrecycling convenience
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent applies homogeneity by making the bulb, dropper base, outer cap, and inner plug all from the same plastic material (polypropylene). This allows the entire dropper cap to be recycled as a single intact unit without disassembly, directly resolving the contradiction between functional optimization and recycling convenience.

Inventive Principle:
Principle #33Homogeneity

2Ease of operation

If components are made from the same material, then recycling becomes convenient, but sealing between components becomes difficult

Engineering Contradiction:
Improverecycling convenienceVSAvoidsealing performance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses segmentation by dividing the sealing function into multiple locations: the first convex ring at the interface between the inner plug and dropper base, and the second convex ring at the interface between the dropper base and bulb. This segmentation of sealing functions allows reliable sealing between same-material components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The convex rings act as intermediary sealing structures between the same-material components. These rings create interference fits that provide both mechanical connection and sealing, eliminating the need for separate gaskets while ensuring reliable sealing performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If interference fit is used for assembly, then sealing is improved, but assembly difficulty increases

Engineering Contradiction:
Improvesealing performanceVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by incorporating chamfers on the insertion ends of the inner plug and dropper base during manufacturing. These chamfers perform the preliminary action of guiding assembly and reducing initial resistance, making the subsequent interference fit easier to achieve while maintaining sealing performance.

Inventive Principle:
Principle #10Preliminary action

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

Facilitates convenient recycling by ensuring components remain intact, reduces production costs through omission of gaskets, and simplifies assembly with chamfered surfaces for improved fit and alignment.

Implementation Method 1

an upper surface of the inner plug is in interference fit with a lower surface of the dropper base through a first convex ring

Methodology Applied
Scientific EffectInterference fit:

Implementation Method 2

an inner sidewall of the lower end of the second cylindrical portion is provided with a first chamfer; an inner sidewall of an upper end of the convex rib is provided with a second chamfer; and an outer sidewall of an upper end of the first cylindrical portion is provided with a third chamfer

Methodology Applied
Scientific EffectMechanical guidance:

Data Source

PatentEP4691311A1Dropper container
Publication Date: 2026.02.11 SHYA HSIN PACKAGING INDUSTRY (CHINA) CO LTD
  • EP4691311A1 patent drawingFigure 1
  • EP4691311A1 patent drawingFigure 2
  • EP4691311A1 patent drawingFigure 3

AI summary

The present disclosure provides a dropper container, including: a dropper cap, an inner plug (500), and a bottle body (600), where the dropper cap includes a bulb (100), a dropper (200), a dropper base (300), and an outer cap (400); a first end of the dropper (200) is fixedly connected to the dropper base (300); a drip nozzle is disposed at a second end of the dropper (200); the dropper base (300) is fixedly connected to the bulb (100); the dropper base (300) is disposed in the outer cap (400); the outer cap (400) is closed onto the bottle body (600); the inner plug (500) is disposed between the dropper base (300) and the bottle body (600); an upper surface of the inner plug (500) is in interference fit with a lower surface of the dropper base (300) through a first convex ring (501); and the bulb (100), the dropper base (300), the outer cap (400), and the inner plug (500) are made of a same plastic material. Therefore, components of the dropper container do not need to be disassembled in recycling, thereby facilitating the recycling.