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Packaging has a large influence on the quality of the contents, on the other hand it encourages the purchasing decisions of the consumers. Both targets are big challenges for product development, especially the packaging of food stuffs. But also other packagings must fulfill many requirements according to its type and its function, e.g. packagings for cosmetics, medicines, chemicals, transport packagings (palettes, crates), industry packagings (big bags, containers, barrels) as well as packagings for electronic instruments and consumption goods.
Since packaging is very different in shapes and materials, it requires especially developed, flexible testing units. We offer a big variety of tools and fixtures and also develop and produce test devices especially to your requirements.
Peeling of covers or sealing materials (Peel Test)
The ability to peel off dimensionally stable or inflexible packagings depends on material combinations, machine parameters as well as on sealed seam and tear-off geometries. A test of the peel forces with a special peel test kit can help to optimize these elements. The most important value is the cracking force but the regularity of the sealing is also significant.
A benefit of the Zwick Roell peel test kit is the exact alignment of the delaminated area with the test axis: The packaging is tracked automatically by the sliding specimen table and this ensures a consistent and reproducible measurement of the load because the peeling angle of 90° is always guaranteed. Furthermore the kit enables a flexible adjustment to fit to different packaging shapes and heights.
Function tests on complete packages
Packaging is manifold and also its function and type of opening. Individual values must be determined since normally no Standards exist.
Examples of such testing:
Compression test on plastic beakers, buckets, boxes, containers, barrels and similar dimensionally stable packagings
Compression tests have different purposes. Examples:
Sealed-seam strength
The determination of the sealed-seam strength of sealings made of flexible packaging material is carried out according to DIN 55529 and other Standards. The test is a tensile test on a 15 mm wide strip with a pull-off angle of 90°. The sealant must have a certain strength according to the use of the packaging material.
Tear test
Standards ISO 34-1, ISO 6383-1, EN 495-2 and DIN 53363 relate to tear tests on plastic foils. The test simulates the behaviour of packaging foils when the package is opened.
When opening a plastic bag, the initial tearing strength should be approximately as much as the remaining tearing strength. If the maximum force at initial tearing is too high, the danger exists that the plastic bag will suddenly tear open completely and the contents will spill out. The ideal behaviour is not easy to adjust because the tear resistance (as well as the tensile strength), is very direction dependent with stretched foils.
90°- / 180° Peel tests
This type of test is used to control the adhesive characteristics as adhesion and tear strength. There are a lot of peel and tear tests with the same principle. Some examples: EN 1719, EN 1939, FINAT test method no. 2, DIN 30646, DIN 55475, DIN 55477.
The reason for the high number is, that different substrate materials and adhesives are used for many different applications. Test plates of glass or stainless steel with a standardised surface are used to compare the adhesion of the different materials. The tests determine the adhesive or adhesion strength: The force that is necessary to tear a strip of a tape constantly from a test plate or glass. The result is the force referred to the width of the tape. Also the tacking often is meaningful: This is ability to adhere to a surface, and to get a measurable tearing force. The adhesion on a substrate is achieved by touching or small contact without using a force.
Tack loop test for testing the adhesive strength of adhesive tapes
Tack is the initial adhesion. It is expressed as the tearing force of a loop material which has been brought into contact with the surface of a test plate.
A strip of a pressure sensitive material is formed into a loop with the adhesive side outwards. With the testing machine the loop is brought in contact with a test plate. When a defined contact area is reached, the loop is pulled off. This test is described in Finat test method No. 9.
Customer specific test devices
On the basis of customer specific requirements, Zwick Roell develops and produces various testing tools and fixtures on short notice.
For examples rigs to determine the push-out force on blister packs, fixtures for special-shape containers or testing tools to test the pull-out force of wine corks as seen in the photo on the right.
Pure materials testing
Basic materials such as plastic, paper and metals have the most varied material tests performed on them.
Mainly according to Standards. e.g.
For more information please visit the relevant application section of our website:
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Plastics