Heat Vulcanization Bonding Agent 823 Rubber To Metal Bonding Adhesive

  Heat Vulcanization Bonding Agent 823  Rubber To Metal Bonding Adhesive

(Secondary Coating Equivalent to Chemlok 220/6125, Chemosil 222)

1. Application

823 adhesive is a secondary adhesive designed for use over 815 primer. This adhesive system will bond uncured elastomers to metals and other rigid substrates during vulcanization of the elastomer. It is formulated without heavy metals and composed of a mixture of polymers, organic compounds and mineral fillers dissolved or dispersed in an organic solvent system.

815 primer helps to ensure environmental resistance of the bonded assembly and adhesion to the substrate.

2. Characteristics

• Wide Application Range–when used in combination with 815 primer, it bonds a wide variety of rubbers such as natural rubber, SBR, neoprene, polyisoprene and polybutadiene to various metals and other rigid substrates.
• Environmental Friendly–formulated without heavy metals.
• Excellent Effect–provides a continuous film appearance.

3. Typical Properties

4. Applying 823

• Surface Preparation: Thoroughly clean metal surfaces prior to primer application. Remove protective oils, cutting oils and greases by solvent degreasing or alkaline cleaning. Remove rust, scale or oxide coatings by suitable chemical or mechanical cleaning methods.
• Chemical Cleaning: Chemical treatments are readily adapted to automated metal treatment and adhesive application lines. Chemical treatments are also used on metal parts that would be distorted by blast cleaning or where tight tolerances must be maintained. Phosphatizing is a commonly used chemical treatment for steel, while conversion coatings are commonly used for aluminum.
• Mechanical Cleaning: Grit blasting is the most widely used method of mechanical cleaning. However machining, grinding or wire brushing can also be used. Use steel grit to blast clean steel, cast iron and other ferrous metals. Use aluminum oxide, sand or other nonferrous grit to blast clean stainless steel, aluminum, brass, zinc and other nonferrous metals.
• For further detailed information on surface preparation of specific substrates, refer to our adhesive application guide. Handle clean metal surfaces with clean gloves to avoid contamination with skin oils.
• For most consistent bonding results, apply the 823 adhesive to 815 primed stainless steel, aluminum, brass or other nonferrous substrates. Allow primer to thoroughly dry before applying 823 adhesive. For further details on the use of 815 primer, refer to the 815 primer data sheet.
• Mixing: Thoroughly stir 823 adhesive before applying adhesive over primer. Agitate sufficiently during use to keep dispersed solids uniformly suspended.

      --Depending on container, use the following recommended mixing method and duration:

      --1/2 pint Hand stir, paint shaker 5-10 minutes

      --1-5 gallon Hand stir and air powered mixer 15-60 minutes

      --55 gallon Hand crank and air motor agitator 8 hours-new drum; continuous-opened drum

• Applying: Apply 823 adhesive by spray, dip, brush or roll coat methods. 823 adhesive is normally used full strength for brush, roll coat and dip application. For spray application, dilute adhesive with xylene or toluene to a Zahn Cup #2 viscosity of 25-28 seconds. Dilution of 25-50% is typical.
• Optimal film thickness for a particular bonded part is dependent on the rubber formulation and the level of adhesion required. Regardless of application method, use the following recommended dry film thicknesses:

815: 5.1-10.5 micron (0.2-0.4 mil)

823: 12.7-25.4 micron (0.5-1.0 mil)

• Drying/Curing: Allow applied adhesive to air-dry for 30-60 minutes at 15-32°C (60-90°F). If humidity is high, drying times may take longer. Drying time can be shortened by either preheating the metal inserts or oven drying after application. Metal parts may be preheated to a maximum of 60°C (140°F) prior to adhesive application. If dry spray or cobwebbing occurs, lower the metal preheat temperature. For coated parts, moderate drying temperatures should be used, but temperatures as high as 93°C (200°F) can be used for short periods of time. Maximum air flow at minimum temperatures will give the best results.

• Dried films of 823 adhesive are non-tacky; therefore, coated parts can be piled into tote pans for subsequent processing. Wear clean gloves when handling cemented parts and cover the tote pans to prevent contamination by dirt, grease, oil, etc. Limit layover times to less than 30 days.
• 823 adhesive cures during the rubber vulcanization process.
• Cleanup–Clean liquid spills with rags. Remove dried material from surfaces with spark-proof equipment and dilution solvents.

5. Sumarry

      Rubber-to-metal adhesive systems are traditionally two-coat systems involving a primer and a topcoat/adhesive that can be utilized to bond a wide variety of elastomers to substrates (typically metal). The mechanism for adhesion relies upon a variety of interactions that occur between the interfaces of the metal, primer, adhesive, and elastomer. In order for an adhesive system to perform its function, it must be utilized properly. This involves consideration of five fundamental aspects of rubber-to-metal adhesion: elastomer type, metal preparation method, primer/adhesive preparation, primer/ adhesive application, and molding operation. Attention to detail regarding each of these aspects of the rubber-to-metal bonding process will allow for a robust bonding operation and a reliable finished part.