3M SJ3522

Design

As a general rule, four square inches of Scotchmate reclosable fastener area per pound of static load to be supported is suggested as a starting point for evaluation. More or less area may be needed depending on specific conditions or end use applications.

Surface Preparation

Highly textured surfaces may reduce the ultimate adhesion levels and care should be given to minimize the surface texture or roughness. Adhesive backed fasteners should be applied to surfaces that are clean, dry and free of oil, grease, dust, mold release agents or surface contaminants that could reduce the adhesion. It is recommended to remove any surface contaminants that may reduce adhesion by using a method suited for the type and quantity of surface contaminants present. Isopropal alcohol is a good general use solvent for cleaning contaminants from surfaces for example.

In exceptional cases, especially when removing silicone mold release agents or on rough, porous surfaces, it may be necessary to lightly abrade the surface, use an adhesion promoter, or surface sealer to optimize the adhesive bond to the substrate. The selection of abrasion, priming or sealing methods will depend upon the substrates and the environmental conditions the product will be exposed to during use.

Application

Attachment Procedure: To obtain optimum bond to any surface, both the fasteners and the target surfaces should have equilibrated for a minimum of one hour at temperatures between 68°F (20°C) to 100°F (38°C) before application. The liner protecting the adhesive is removed and preferably without touching the adhesive, the fastener is applied to the substrate. Exposure of the adhesive to ambient conditions without the protective liner, before applying to the surface, should be minimized as initial adhesive tack may decrease. Flexible materials should be lying on a hard flat surface so as to permit uniform adhesive contact with the surface. Use of a rubber hand roller, press platen or similar device is recommended to ensure full adhesive contact or wetout with the substrate surface. Approximately 4.5 pounds of force per square inch, (310 grams per square centimeter) is recommended to increase adhesive contact, improving bond strength. For all adhesive applications, it is important to ensure that the edges are rolled down to reduce the chance of edge lifting.

Plain backed: The plain backed 3M hook and loop fasteners are most commonly sewn into their applications. Liquid or hot melt adhesives and staples are other forms of attachment that can be utilized.

Sewing: Although the selvedge edge was initially developed for stitching on, customers often find that they get better anchorage when stitching through the 3M hook and loop portions of the fastener – this may be application dependant. The type of thread and stitch type is also best determined based on individual application, however, the fastener should be stitched on all edges for the best seam strength. Typically, special machine adjustments are not necessary when using our 3M hook and loop fasteners.

Curing

Parts with properly chosen and applied pressure sensitive adhesive reclosable fasteners can be handled immediately. As the adhesive further wets-out the adherend surface, adhesive bond strength increases after application with time, pressure and/or temperature. Once attached to the adherend, a 1-day minimum dwell time is recommended before applying a load or disengaging mated Scotchmate reclosable fastener pieces. This dwell time is important for achieving a firm adhesive bond before applying a load or using. The adhesive on 3M™ Scotchmate™ Reclosable Fasteners SJ3522 and SJ3523 achieves approximately 50% of the ultimate bond strength within 1 hour, 90% after 1 day and the ultimate bond strength of properly applied fasteners is obtained within 3 days at 72°F (22°C) and 50% relative humidity. Primers or adhesion promoters may reduce the time required to achieve the ultimate bond strength.