Polymerizable Mixture Supply Under Vacuum to Prevent Bubble Defects

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Solution Overview

Problem

The introduction of nitrogen into a tank containing a polymerizable mixture to supply a molding device can lead to gas dissolution, resulting in bubbles trapped in the final molded article, making it defective.

Innovation Solution

A method and device that maintain a pressure in the tank lower than ambient pressure during and after supplying the molding device, using a vacuum regulator and inert gas to control pressure, forming a closed loop to continuously degas and prevent regassing, ensuring the polymerizable mixture remains degassed throughout the supply process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If nitrogen is introduced into the tank to increase pressure and push polymerizable mixture towards the molding device, then the supply pressure is improved, but gas dissolves in the polymerizable mixture causing bubbles in the final article

Engineering Contradiction:

Improvesupply pressureVSAvoidgas dissolution

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

Instead of pressurizing the tank with gas to push the polymerizable mixture (conventional approach), the invention inverts the approach by maintaining the tank under negative pressure (vacuum). This prevents gas dissolution while still enabling supply through a pressure differential created by the pumping system.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention creates an inert environment in the tank by maintaining negative pressure, which prevents atmospheric gases from dissolving in the polymerizable mixture. The vacuum state acts as a protective inert environment that eliminates the harmful gas dissolution effect.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Object-affected harmful factors

If the tank is kept under negative pressure to prevent gas dissolution, then bubble formation is reduced, but continuous supply to the molding device becomes difficult

Engineering Contradiction:

Improvebubble formationVSAvoidcontinuous supply capability

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention introduces a pumping system as an intermediary between the negative pressure tank and the molding device. The pump mediates the transfer of polymerizable mixture by creating a pressure differential that enables flow from the negative pressure tank to the positive pressure molding device, thus resolving the contradiction between maintaining negative pressure and achieving continuous supply.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts pressures at different points: the tank maintains negative pressure to prevent gas dissolution, while the molding device operates at positive pressure for proper filling. The pumping system dynamically manages the transition between these two pressure states to ensure continuous supply.

Inventive Principle:

Principle #15Dynamics

3Productivity

If a looping line is used to continuously circulate the polymerizable mixture, then continuous supply is achieved, but gas may be re-dissolved during circulation

Engineering Contradiction:

Improvecontinuous supplyVSAvoidregassing

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The negative pressure in the tank acts as a counterweight force against the tendency of gas to re-dissolve during circulation. By maintaining a pressure gradient where the tank is under negative pressure, the system continuously counteracts the regassing tendency that occurs during the circulation process in the looping line.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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

Reduces the number of defective molded articles by effectively preventing gas dissolution and trapping, ensuring a continuous supply of degassed polymerizable mixture to the molding device.

Implementation Method 1

reaching a set value of pressure in the tank, smaller than the ambient pressure

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

an entry of inert gas into the tank is controlled based on the pressure contained within the tank

Methodology Applied

Scientific EffectGas dissolution prevention:

Data Source

PatentUS12558859B2Method for supplying a molding device with polymerizable mixture

Publication Date: 2026.02.24 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

The invention relates to a method for supplying a polymerizable mixture to at least one molding device, said method comprising the following steps: a) providing a tank containing the polymerizable mixture (box E1), b) reaching a set value of pressure (Ps) in the tank, smaller than the ambient pressure (box E2), c) continuously maintaining the pressure (P) in the tank at the set value of pressure while supplying the polymerizable mixture to the molding device (boxes E3, E4, E41, E42, E5, E51). The invention also relates to a supply device for supplying the molding device with polymerizable mixture.