GORE™ Packaging Vents Frequently Asked Questions
-
-
-
-
-
- How can I test the performance of a vent?
- What packaging test standards do GORE™ Packaging Vents meet?
- What if Gore’s standard product forms do not meet my needs?
- What would cause a sudden pressure change?
- Does the membrane vent in both directions?
- What kind of applications are Gore vents used in?
1. How do I know if I need to vent my container or package?
GORE™ Packaging Vents are useful in a wide variety of applications where it is necessary to relieve the pressurization effects of gas scavenging, off-gassing or environmental changes on a container, bottle or package. Gas-permeable container vents are necessary for these reasons:
-
To release the pressure in containers of certain industrial and commercial chemicals which off-gas and often cause a container to swell or burst
-
To equalize the pressure in containers of certain industrial and commercial chemicals which scavenge gas in the free space above the liquid and often cause the container to collapse and/or tip over
-
To release the pressure from containers while preventing leakage and ingress of water, bacteria and particulate
-
To equalize the pressure in the container during shipment or storage due to changes in temperature or altitude
GORE™ Packaging Vents are gas-permeable and enable the rapid exchange of air and other gases through the membrane vent material in response to environmental changes such as temperature and altitude. Unlike traditional venting options, GORE™ Packaging Vents offer a unique solution to venting by allowing the container to breathe while providing a leak-proof barrier against water, bacteria and particulate ingress.
[back to top]
2. How does a vent work?
GORE™ Packaging Vents are constructed of of expanded polytetrafluoroethylene (ePTFE). The material prevents liquid penetration, while allowing airflow and equalizing pressure. When splashed by a viscous liquid, the membrane will quickly recover its venting capability. GORE™ Membranes offer varying airflow rates and resistance to wetting by low surface tension liquids.
W.L. Gore & Associates, Inc. invented ePTFE and continues to be a world leader in fluoropolymer technologies.
[back to top]
3. What vent material and size do I need for my container?
Typically the optimized choice of a container vent depends on two requirements:
The airflow requirement is defined as the volume of air which must be exchanged between the inside and the outside of a container, in a given amount of time. It can be influence by several factors, including:
Airflow is measured using a Gurley densometer, which measures the amount of time required to pass 100 cc of air through 1 square inch of material at 0.17 pounds per square inch (12 mbar). Typically this is converted to airflow in liters per hour.
In order for a container vent to perform properly, there must be sufficient airflow AFTER liquid contact. This is the best measure of liquid resistance. Gore's super-resistant ePTFE membranes are designed to offer the best liquid resistance of any commercially available fluoropolymer materials, for the widest range of possible contact fluids. Liquid resistance is strongly influenced by the chemistry of the liquid in the container (see question# 5 below). Typically the liquid resistance is quantified by measurement of the materials water entry pressure (WEP), otherwise known as water breakthrough pressure (WBP). WEP is defined as the amount of pressure necessary to force water through a membrane, normalized for a given area.
A GORE™ Packaging Vents sales associate can help determine the right container venting configuration required to maintain packaging integrity and product quality. GORE™ Molded Components and GORE™ Liners are available in standard sizes and materials with predetermined airflow and WEP levels.
[back to top]
4. My new liquid is “wetting-out” the existing vent design. What does Gore have to prevent this?
If the surface tension of a contact liquid is lower than the surface tension of the solid that it rests on, the liquid will readily "wet out" or penetrate the surface. This penetration can prevent airflow after liquid contact. If the surface tension of the solid is lower than the surface tension of the contact liquid, the liquid will form a droplet and "roll off" the surface.
Gore's super-resistant membranes are designed to prevent "wet out", forcing even challenging fluids (such as those with solvents and surfactants) to "roll off" the vent, as shown in the pictures below.
[back to top]
5. What vent form should I use?
Gore offers a range of container venting products to meet your application requirements, including molded components, cap liners and induction liners. All of these products integrate easily to simply create a vented closure / cap vent.
-
Molded components snap into place and fit containers of various sizes from 0.2 to 1,500 liters.
-
Cap liners simply replace the existing liner to provide venting with excellent liquid resistance.
-
Induction liners allow high-frequency (HF) induction sealing of foil to container to provide tamper evidence in addition to venting and excellent liquid resistance.
Custom configurations are also available. Contact Us to discuss specific application and configuration requirements.
[back to top]
6. How can I test the performance of a vent?
When designing and implementing a container construction, it is necessary to understand the real-world conditions in which the product will be used. The optimal performance of any GORE™ Packaging Vent depends on how the vent interacts with these factors:
-
container or package design
-
amount of venting required
-
liquid / surface interactions
Gore application engineers have developed standard test protocols to confirm airflow and water entry pressure (WEP) for various design configurations. In addition, Gore also has custom analytical testing capabilities that can be designed to meet the exact need of your application.
[back to top]
7. What packaging test standards do GORE™ Packaging Vents meet?
GORE™ Packaging Vents have consistently demonstrated compliance with UN and DOT package test standards.
Gore can provide general guidelines based upon its experience with GORE™ Packaging Vents however the manufacturer is ultimately responsible for validating each product and its performance for the intended application.
[back to top]
8. What if Gore’s standard product forms do not meet my needs?
Based on our experience in venting and knowledge of ePTFE membranes, Gore has optimized its product portfolio to include a range of sizes and shapes to fit a variety of applications that require a container vent solution. Gore offers a number of different parts in a variety of sizes, forms, airflow requirements, and levels of liquid resistance. Custom parts and sizes are also available upon request. A Gore representative can help determine which container venting solution will work best in a specific application.
[back to top]
9. What would cause a sudden pressure change?
Temperature, altitude or other environmental factors can cause rapid changes in pressure. If the pressure or vacuum becomes too great, a container may swell or collapse, allow contaminant ingress, and even leak. GORE™ Packaging Vents permit pressure to equalize with the immediate environment by allowing the container to breathe. GORE™ Packaging Vents offer both proven protection and venting technology to meet the most stringent market needs.
[back to top]
10. Does the membrane vent in both directions?
Yes. GORE™ Packaging Vents allow the passage of air and other gases in both directions while containing the liquid within. Gore offers a range of materials with varying airflows to optimize container integrity while preventing leakage.
[back to top ]
11. What kind of applications are GORE™ Packaging Vents used in?
GORE™ Packaging Vents are used in a variety of applications across many market segments. The combination of our proven proprietary hydrophobic and super-resistant ePTFE technologies, product variety, and range of product forms make Gore an ideal choice when a product needs both venting and liquid resistance. Closure vent solutions from Gore are an effective way to maintain product and container integrity for a variety of different container shapes and sizes in a wide array of different applications.
|
Typical chemicals and applications include:
|
|
Chemicals
|
Applications
|
|
|
|
[back to top]
|
