Buying inner patches and pull tabs: why width alone is not enough
Identify inner patches and pull tabs by their application, material reference, reel dimensions and approved specification.
An inner patch, also described as an IS-strip, and a pull tab should be identified as different purchasing items. An enquiry should connect the material’s function, current reference, package opening and equipment requirements. Equal width does not establish interchangeability.
Identify the application first
For an inner patch, describe its position and function in the internal sealing arrangement. For a pull tab, describe the external sealing and opening arrangement. Photographs of the inside and outside of the package, an opening drawing or the current material label can help the technical team identify the actual construction.
| Purchasing item | Information to establish first |
|---|---|
| Inner patch / IS-strip | Internal sealing position, existing material reference, opening construction and relevant equipment |
| Pull tab / tab-strip | External sealing and opening arrangement, existing material reference, opening construction and relevant equipment |
| Both items | Width, thickness, reel configuration, tolerances and specification revision |
These descriptions do not mean that every carton uses the same opening construction. Confirm the actual package and material combination rather than assuming that one size covers all applications.
Separate material dimensions from reel dimensions
Material width, material thickness, core inner diameter, reel outside diameter and length per reel describe different properties. Preserve the field names and units when requesting quotations. Core width should not be confused with material width, or reel outside diameter with core inner diameter.
When comparing specifications, check whether each figure is a nominal value, limit or tolerance. If references or units differ, establish their correspondence before discussing a replacement or sample.
Match the material structure to the product reference
Include the relevant structure and property sections of the current specification. Where barrier, tensile or layer-bonding performance needs comparison, confirm the units and test conditions as well. A single value does not establish suitability for the complete package and does not replace review of the equipment and material combination.
A proposed material should have an identifiable reference and agreed specification revision. Before a first sample or trial, the factory and supplier should agree what needs checking and who is responsible. Photographs or similar names alone should not be used to approve substitution.
Prepare one complete enquiry
Provide the current material reference, label photographs, an opening photograph or drawing, material dimensions, reel requirements, equipment reference, quantity and destination. For an existing production observation, include the material batch and a description of the observation.
When contacting Shengli Pak about packaging accessories, include the current reference and application position. The supply proposal should follow the material requirements confirmed through technical review.
Related reading: Packaging accessories, LS strip functions, cap selection, regional contacts.