2. 2
The older technology adhesives used for Industrial applications which
include Automotive assembly and repair, have been polyurethane and
epoxy technology and are being replaced with the new and greener
hybrid sealants using Risun Polymers where solvents and
isocyanates are not present, and are a safer product for plant
operators and tradesmen.
The adhesives used in these areas have much higher tensile
strength requirements , usually starting at about 3.0 Mpa
tensile at break and can go up to 6.0 Mpas . These adhesives
need good adhesion to the surfaces bonded , and usually are
required to have a fast cure at room temperature from 5
minutes to 15 minutes .
The adhesives need to have high tensile strengths with some
elongation and good tear strength, which these Risun Polymers
can accommodate.
For the Adhesive manufacturer these adhesives need different
Risun Polymers compared to Construction markets, as the
adhesives contain very little plasticizer and the reinforcing
additives such as precipitated calcium carbonate and carbon
black are processed with higher levels of catalyst and adhesion
silanes.
These requirements of the Automotive and Industrial markets
can be met by the use of the dimethoxy silane based Risun
15000DS and Risun 12000DS Polymers ,where the adhesion of
this molecule has been shown to be improved, and the curing
mechanism releases small amounts of methanol with no
bubbles like fast polyurethane adhesives. These polymers are
very easily processed with Precipitated calcium carbonates and
carbon black powders, and produce very tough adhesives with
good tensile and tear strengths.
These Risun 15000DS and R12000DS Polymers can also be
mixed with some trimethoxy Resins in a second step such as
Risun R3000T to produce a faster curing system where there is
also less of the tin Diketonate catalysts added for faster curing.
The R15000DE and R12000DE Polymers use the more
environmentally friendly tin diketonate catalyst and secondary
amino silane chemicals as the curing mechanism . They also
reduce the amount of methanol released.
Below we show some starting formulations and typical
applications of these Risun Polymers for adhesives in Industry.
INDUSTRIAL
ADHESIVES
3. 3
Risun polymers are based on the new generation
polyether polyols ,that are the same as used for PU
adhesives and capped with reactive silanes that are
the same as used by some silicone sealants, and this
is where the hybrid name comes from.
The polyether chain is about twice the strength of the
polysiloxane chain used in silicone adhesives and
lets the adhesive have better recovery from shear
movement and is also more compatible when mixed
with additives that do not come out of the sealant.
The crosslinking of the sealant to form the one part
curing sealant uses the dimethoxy silane chemistry
as used by some silicone sealants. The adhesion is
excellent and in most cases with metals like
aluminium there is no need for primers.
The other big advantage over polyurethane adhesive
is that there is no solvent , there are no bubbles
formed when the adhesive cures and the vapour
released at low levels is methanol.
Adhesive Company formulators can mix resin systems to
control crosslinking and movement capacity of adhesives
RISUN 15000DS and R12000DS polymers
Dimethoxy silane capped polymers for high tensile and
tough adhesive formulations . Easy processing with
PCC and Carbon Black
Enables bubble free curing at normal temperature &
humidity levels.No solvents in the adhesive.
Formulations have excellent adhesion to metals
with fast cure that can be adjusted
Excellent adhesion to aluminium with no primers
and a wash with green dimethyl carbonate solvent
Adhesives cure with some methanol vapour which is
safer for use in confined factory applications
compared to solvents like xylene
Adhesive formulations can use the standard PPC
fillers and carbon black for high tensile strength
Adhesives are solvent free and isocyanate free
and safer for Processing in Factories
Adhesives can be made in the factory with maximum
mixer temperatures of 60 degree C and low energy use
The trifunctional polymer is catalysed with more
environmentally friendly tin acetoacetate catalyst
.
No hazard warning labels on the sealant product
when displayed in the factory . Vinyl silane is
used as moisture scavenger.
Formulations can be thickened with carbon black,
polyamide wax or cheaper urea thickeners
Design of Difunctional Risun
Polymers
4. 4
Starting Formulation
Risun 12000DS based Industrial
adhesive BLACK
Test Results
MANUFACTURING GUIDELINES.
PCC precipitated filler is of very small particle size and very hard to dry when wet , so in Humid environments some
predrying at 120 degree is recommended.
Risun 12000DS and the PCC and other powders are loaded into the mixer and dispersed under high shear and
vacuum to disperse the PCC in the resin and remove most moisture with high vacuum .Get the mixture to 50 degree
C and keep there for 1 hour and check moisture with carl fischer equipment.
At 50 degree the vacuum is reduced and the vinyl silane is added under nitrogen to chemically remove remaining
moisture.
The dry paste is now ready for addition of silanes and catalyst to finish the process.
Very high tensile strengths are obtained by addition of carbon black at levels from 5 to 10 percent in the adhesive
formulation , and an option is to disperse the carbon black in the resin like Risun 12000DS in a separate process.
When the thickener system like carbon black paste is added and the mixture smooth , the formulation can be finished
with final additions under nitrogen blanket and some vacuum .
Material Parts by Weight
1. Polymer RISUN 12000DS 1800
2. Reinforcing filler Precipitated calcium carbonate 1800
3. Pigment Carbon black or titanium dioxide 120
4. Chemical drier Vinyl silane 30
5. Antioxidant Irganox 1076 15
6. Thixotropic Agent Polyamide wax or urea thickener 10
7.UV inhibitor Tinuvin 765 15
8. Adhesion Promoter Secondary amino silane KBM603 20
9. Catalyst dibutyl tin diacetylacetonate,KRA-1 20
10. Moisture scavenger Vinyl silane, A171 20 As needed.
Standard
Tack free time 10 minutes
Shore A penetration 55 ISO 868
Tensile strength at break 3.2 Mpa ISO 37
Elongation at break 250 percent ISO 37
5. 4
Starting Formulation
Risun 15000DS in white industrial
adhesive
Test Results
MANUFACTURING GUIDELINES.
PCC precipitated filler is of very small particle size and very hard to dry when wet , so in Humid environments some
predrying at 120 degree is recommended .This is the same for Tio2
Risun 15000DS and the PCC,TIO2 and DIDP are loaded into the mixer and dispersed under high shear and vacuum
to disperse the PCC,TIO2 in the resin and remove most moisture with high vacuum . Get the mixture to 50 degree C
and keep there for 1 hour and check moisture with carl fischer equipment.
At 50 degree the vacuum is reduced and the vinyl silane is added under nitrogen to chemically remove remaining
moisture. When Dry under nitrogen the remaining chemicals and catalyst are added under Nitrogen ,and the final
addition of vinyl silane acts as the moisture scavenger in the Cartridge and can affect open time or tack free time.
In the final step vacuum the mixture for short time to remove all bubbles.
The process above is very simple and a practical way to make one part moisture curing sealants and adhesives in a
humid environment as is common across the Asian continent.
Material Parts by Weight
1. Polymer RISUN 15000DS 1200
2. Reinforcing filler Precipitated calcium carbonate 1500
3. Plasticizer DIDP 400
4. Chemical drier Vinyl silane 30
5. Thickener Aerosil R972 50
6. Tio2 white pigment Paint grade 120
7.Stabilizer and UV inhibitor Irganox 1076 and Tinuivin 765 30
8. Adhesion Promoter Secondary amino silane KBM603 10
9. Catalyst Dibutyl tin diacetylacetonate ,KRA-1 15
10. Moisture scavenger Vinyl silane 15
Standard
Tack free time 30 minutes
Shore A penetration 40 ISO 868
Tensile strength at break 2.3 Mpa ISO 37
Elongation at break 400 percent ISO 37
6. Please contact Risun Polymers for advice on
formulations and the correct polymer to use for
applications as well as a starting formula.
