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
Color | Black Liquid |
Viscosity @25℃, 77 ℉(Brookfield LVT Spindle 2, 30 rpm ) | 70-300 cps |
Density | 975.0-1000.0kg/m3 |
Solid content by weight | 23-27% |
Flash Point(seta) | 25-28℃ |
Solvent | Xylene |
Shelf life | 12 months in unopened containers (21-27°C (70-80°F)) |
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.