3M SJ3550

Design

Design Considerations: As a general rule, four square inches of fastener area per pound of static tensile or shear 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. Type 250 Dual Lock reclosable fastener less than 0.75" (19 mm) width should not be engaged to other type 250 Dual Lock reclosable fastener as low disengagement values may occur

Rounding the corners, recessing the product into the substrate and providing raised edges around the Dual Lock reclosable fastener can reduce the possibility of edge lifting or catching that may cause the fastener to be torn from the substrate, while improving the overall appearance of the fastener on the finished product. Mechanically securing the corners of the Dual Lock reclosable fastener can also reduce the possibility of edge lifting, but may reduce the closure performance.

It is recommended that pieces of Dual Lock reclosable fastener be engaged to pieces or strips of Dual Lock reclosable fastener. Strips of Dual Lock reclosable fastener should not be engaged to strips of Dual Lock reclosable fastener as low disengagement may occur from incomplete engagement along the full strip. Pieces or strips of Dual Lock reclosable fastener can be engaged to pieces or strips of Scotchmate reclosable fastener loop.

Surface Preparation

The substrate surface should be cleaned to remove any surface contaminants with an appropriate cleaning method for the customer’s substrate, type and quantity of surface contaminants that need to be removed.

Note: When using solvents, extinguish all ignition sources, including pilot lights, and follow the manufacturer’s precautions and directions for use.

Application

The fasteners and substrates should have equilibrated for a minimum of one hour at temperatures of 68° to 80°F (20° to 27°C) before application. Generally these adhesive backed fasteners should be applied to surfaces that are smooth, dry and free of oils, mold release agents or other surface contaminants.

After the substrate surface has been cleaned and dried, the liner is removed from the fastener adhesive and without touching the adhesive, the fastener’s adhesive is applied to the surface using light finger pressure. The fastener must be rolled down, to increase contact of the adhesive with the substrate’s surface. Extra care must be exercised when rolling down Dual Lock reclosable fasteners to prevent bending of the stems which can compromise the closure strength. The following two methods allow adequate pressure to be applied to the Dual Lock reclosable fastener without damaging the stems

The first method uses a hand roller, with the roller wheel covered with a Dual Lock reclosable fastener type 170 such as 3M™ Dual Lock™ Reclosable Fastener SJ3542. The Dual Lock reclosable fastener covered roller is rolled over the Dual Lock reclosable fastener applied to the substrate, engaging and disengaging the two Dual Lock reclosable fastener pieces. The hand roller can be used for many applications.

The second method consists of engaging a strip of plainback Dual Lock reclosable fastener type 170 such as 3M™ Dual Lock™ Reclosable Fasteners SJ3442 or SJ3742 to the previously attached adhesive backed Dual Lock reclosable fastener. The backside of the plainback material can now be rolled down using a rubber roller, with no Dual Lock reclosable fastener on the roller, fully engaging the Dual Lock reclosable fastener. After rolling down three times in each direction, the strip of plainback Dual Lock reclosable fastener can be removed and used to roll down the next piece of Dual Lock reclosable fastener in a similar manner.

Curing

The pressure-sensitive adhesive bonds to the substrate on contact and parts can be handled immediately. Adhesive bond strength increases with time, pressure and temperature. A minimum of twenty four hours dwell time is recommended before applying a load or disengaging assembled parts. Recommended time at room temperature to achieve maximum bond strength is 72 hours