Adhesive for bonding Silicone Rubbers to Metals and Fabrics.

Introduction

Polyloc 450 is a single coat adhesive system for bonding unvulcanised silicone rubber compounds to metals during the vulcanisation of the elastomer. This adhesive system produces bonds that are outstandingly resistant to all kinds of environmental conditions and corrosion and capable of withstanding extreme static and dynamic stresses.

Polyloc 450 is used in the manufacture of various industrial items like Oil Seals, Printing Rollers, and other rubber to metal bonded products.

Properties of Polyloc 450

Composition	Solution of Synthetic Organic Silicones in Methanol
Color	Colorless solution.
Reactive Mat’l	9 ~ 11%.
Diluents	Methanol.
Specific Gravity	0.83.
Shelf Life	At least 1 year
Flash Point	10 dC.

Preparation of Metal Surface

This is the most critical step for any rubber to metal bonding process. The metal surface should be cleaned of all contaminants such as oil, rust, dirt, etc. by suitable mechanical and/or chemical methods.

Grit/sand blasting, and wire cloth abrading are commonly established mechanical methods of metal preparation for most metals, and give excellent results. Chemical treatment of the metal surface by phosphatising results in a highly corrosion resistant and bondable surface. The general steps are: Water rinse - Acid pickle - Water rinse - Phosphatise - Water rinse - Chromate rinse.

Application of the Adhesive

Polyloc 450 may be applied by dip, spray or brush depending on the size and nature of the surface to be coated. Brushing is the most widely used method. The application of a thin and uniform coating of the adhesive, free from excessive runs, tears or fatty edges is an essential condition for optimum bonding results. The adhesive may be colored by adding 0.1% by weight of powdered Methylene Blue dyes.

Dilution of the adhesive should be done just before application. The degree of dilution to be done will finally depend on the required strength of the bond. Do not return unused adhesive to the original container.

Polyloc 450 takes 30 minutes to dry at room temperature. For faster drying, drying ovens can be used. The coated parts should be used within 24 hours of adhesive application. They should be given another coat of the adhesive if they are not used within this period of time.

Vulcanisation / Bonding

Prepare compound of the elastomer and vulcanise as per manufacturer’s specifications. Appropriate post-vulcanisation treatment for the elastomer will not deteriorate bond strength.

Presentation of a fresh rubber stock surface at the bond interface results in better bonds. The adhesive can be subjected to a reasonable pre-baking period which generally occurs in multi-cavity molds. However it is advisable to load the adhesive coated metal parts and fill the cavity with rubber compound in the minimum amount of time.

Basic care should be taken in removing the hot bonded parts from the molds so as to prevent any damage to the bond. The bonds will gain their full strength after cooling and maturing for 10-12 hours.

Cautionary Information

This product is meant for industrial use only. It contains highly volatile solvents; keep product away from heat, direct sunlight and open flame. Vapors may be harmful and prolonged breathing should be avoided. May be harmful or fatal if swallowed.