Coated fabrics and laminated fabrics are used in sewn fabric dunnage to help protect parts during packaging, shipping, and assembly. Part shapes, sizes, and surfaces vary, but rack bag designers generally want fabric dunnage materials that are strong, lightweight, and long-lasting. Laminated fabrics can provide useful properties such as strength and durability, but some packaging engineers choose coated fabrics instead. What’s the right choice for your reusable packaging application?
In Part 1 of this series, Hold-True examined laminated fabrics for rack bags and described the advantages and disadvantages of these fabric dunnage materials. In Part 2, we’ll take a look at coated fabrics and consider both their strengths and their weaknesses. By understanding all of your requirements, you can select rack bag materials that support not just your packaging, shipping, and assembly application, but also your organization’s need for a strong return on investment (ROI).
What are Coated Fabrics?
Coated fabrics are woven or non-woven cloth with a specialized coating that’s applied to the surface of the material, or saturated into the material’s bulk. The coating is usually a polymer or elastomer that imparts particular properties, such as resistance to water, mildew, or sunlight. Coatings that increase puncture-resistance or that help make rack bags easier-to-clean are also used. Typically, these coatings are applied to the base fabric in a viscous or syrup-like form.
Natural Fibers and Synthetic Fibers
With coated fabrics, the base material may contain either natural or synthetic fibers. Natural fibers such as cotton can be recycled, but they absorb moisture and are less durable. Synthetic fibers such as polypropylene (PP) combine strength and durability with weather resistance and ease-of-cleaning. Coatings for fabrics also include polyvinyl chloride (PVC), high density polyethylene (PE), and low density polyethylene (PE). PVC resists water, but still promotes mold or mildew growth.
Advantages of Coated Fabrics
Coatings can reduce the tensile strength of fibers, but the advantages of coated fabrics outweigh their disadvantages – especially when compared to laminated fabrics. For example, coated materials tend to weigh less per square yard. They won’t de-laminate either. With coated fabrics, the coating and the base fabric tend to act as a single material. With laminated fabrics, each of the constituent materials must work well together, yet each layer tends to act as a separate material.
How to Increase Coated Fabric Strength
To address concerns about how coatings reduce tensile strength, Hold-True can source coated fabrics with a scrim for reinforcement. This strong but lightweight mesh or netting increases a coated fabric’s resistance to tearing under tension. Scrim also increases resistance to tongue or tab tear from ripping. Hold-True can also manufacture your parts bags with ripstop materials, woven fabrics that use a special reinforcement technique.
Learn More about Fabric Dunnage Materials
At Hold-True, our primary coated fabric is a woven material that provides durability and supports rack bag manufacturing. Woven strips of HDPE that are coated with LDPE are a great choice for sewn, reusable packaging that needs to withstand the elements and provide a strong ROI. For more information about choosing fabric dunnage, contact Hold-True at our facility in Mansfield, Ohio (USA)