COATING COMPOSITION COMPRISING A SILICONE RESIN, A FLUOROCARBON POLYMER, AN EPOXY RESIN, A SILICONE FLUID, AND AN INORGANIC HARDENING AGENT

PRODUIT DE REVETEMENT COMPRENANT UNE RESINE DE SILICONE, UN POLYMERE DE FLUOROCARBONE, UNE RESINE D'EPOXYDE, UN FLUIDE A BASE DE SILICONE ET UN AGENT INORGANIQUE DE DURCISSEMENT

English Abstract

ABSTRACT OF THE DISCLOSURE
A coating composition comprising an inert liquid
carrier and solids including a binder containing a methyl-
phenyl polysiloxane resin, a thermocarbon polymer and an
epoxy resin, and also a dimethyl polysiloxane fluid and an
inorganic hardening agent. The composition forms finishes
that have thermal stability, release properties, high glass,
hardness, abrasion resistance, and excellent adhesion to
unprimed, untreated metal substrates.

Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined as
follows:
1. A coating composition having a solids content
of 25-80% by weight in an inert liquid carrier and com-
prised of:
(a) a binder comprised of
(1) 40-93% by weight, based on the weight of
the binder, of a silicone resin which is a
heat curable structured methylphenyl poly-
siloxane resin having
the repeating structural formula
<IMG>
wherein
X is a functional group which allows
cross-linking at its site, and
a, b, c, and d are positive integers
which are sufficiently large to
provide the resin, when measured
at 60% resin solids in xylene at
25°C, with a viscosity of 30-50
centipoises, specific gravity of
1.03-1.2, and refractive index of
1.45-1.57; and having
a silanol content above 4% based on
the weight of the resin;
(2) 5-50% by weight, based on the weight of
the binder, of a fluorocarbon polymer; and
(3) 2-40% by weight, based on the weight of the

binder, of an epoxy resin having the
formula
<IMG>
wherein
n is an integer from 0-42, and
R is an alkylene group of 1-4 carbon
atoms;
(b) 0.2-10% by weight, based on the weight of the
binder, of a silicone fluid which is a dimethyl
polysiloxane fluid having a viscosity of
50-5000 centistokes measured at 25°C;
(c) a finely divided inorganic hardening agent in
a hardening agent to binder ratio of about
5/100 to 400/100; and
(d) an inert liquid carrier.
2. The coating composition of claim 1 wherein
the binder is comprised of
(a) 65-85% by weight, based on the weight of the
binder, silicone resin,
(b) 10-20% by weight, based on the weight of binder,
fluorocarbon polymer; and
(c) 5-15% by weight, epoxy resin.
3. The coating composition of claim 2 comprised
of
1-3% by weight, based on the weight of the binder,
silicone fluid; and
hardening agent in a hardening agent to binder ratio
of about 10/100 to about 70/100.
-16 -

4. The coating composition of claim 1 wherein
the silicone resin has a
silanol content above 5%, based on the weight of the
resin,
softening point of about 75-88°C; and,
when measured at 60% resin solids in xylene at 25°C,
a viscosity of about 35-45 centipoise,
specific gravity of about 1.05-1.12, and
refractive index of about 1.50-1.53.
5. The coating composition of Claim 1 wherein
the fluorocarbon polymer is a copolymer of tetrafluoro-
ethylene and hexafluoropropylene.
6. The coating composition of claim 1 wherein
the epoxy resin is a liquid having a viscosity of 1.2-225
poises
at 25°C, and an epoxy equivalent of 150-470; and
wherein
n is an integer from 0-3 and
R is isopropylidene
7. The coating composition of claim 1 wherein
the silicone fluid has a viscosity at 25°C of about 500-
1500 centistokes.
8. The coating composition of claim 1 wherein
the hardening agent is an alumina.
9. The coating composition of claim 1 containing
pigment in a pigment to binder ratio of about 1/100 to
about 400/100; and a wetting agent in a concentration of
0.2-10% by weight, based on the weight of the binder.
10. The coating composition of claim 1 wherein
(a) the binder is comprised of
17

(1) 65-85% by weight, based on the weight of
the binder, of a silicone resin having
(a) silanol content above 5% based on
the weight of the resin,
(b) softening point of about 75-85°C, and
(c) when measured at 60% resin solids in
xylene viscosity of about 35-45 centi-
poises, specific gravity of about
1.05-1.112, and refractive index of
about 1.50-1.53;
(2) 10-20% by weight, based on the weight of
the binder of fluorocarbon polymer which
is a copolymer of tetrafluoroethylene and
hexafluoropropylene; and
(3) 5-15%, by weight, based on the weight of
the binder, of liquid epoxy resin having
a viscosity of 1.2-225 poise at 25°C, and
an epoxy equivalent of 150-470; and
wherein
n is an integer from 0-3 and
R is isopropylidene;
(b) 1-3% by weight based on the weight of the binder
of a silicone fluid having a viscosity of
500-1500 at 25°C;
(c) hardening agent which is alumina in a hardening
agent to binder ratio of about 10/100-70/100;
(d) pigment in a pigment to binder ratio of about
1/100 to about 400/100;
(e) wetting agent in a concentration of 0.2-10%
by weight, based on the weight of the binder; and
18

(f) inert liquid carrier.
11. A cooking vessel having its food-contacting
surface coated with a film produced by curing the coating
composition of claim 1.
18

Description

10~274Z
BACKGROUND OF THE INVE~ITION
~1) Field of the Invention
Thi9 invention i9 directed to a coating composition
that i8 useful as a finish for cooking vessels because
of its thermal stability, release properties, gloss,
hardness, abrasion resistance, and adhesion to untreated,
unprimed metal substrates.
(2) Prior Art
Cookware and bakeware items have been coated
with fluorocarbon polymers such as polytetrafluoroethylene
and copolymers thereof. Finishes of fluorocarbons have
excellent thermal stability and good release properties
and have been widely used and well accepted.
However, a primer is generally required for
these coatings, along with special treatment of the metal
substrate, to obtain excellent adhesion of the coating.
Moreover, the few coating compositions which do not require
a primer or substrate treatment are only available in
dark colors.
Therefore, it would be desirable to have a
coating composition that could be applied to an unprimed
untreated substrate and which could provide a light colored
finish upon baking.
The coating composition of this invention meets
the above desires while forming a finish that has release
properties, thermal stability, high gloss, good hardness,
and abrasion resistance, and is an ideal coating composition
for cooking vessels, particularly bakeware, and commercial
food processing equipment.
- 2 -

10!92742
gU~MARY OF T9~ IJVE~TIO~
A coating eo~pooltlon o~ this lnvention ha~ a ~olld~
content Or 25-80% b~ ~elght ln an ln-rt llquld carrler and is
coaprloed Or
(a) a binder eo~prl~ed o~
(1) 40-93% b~ ~elght, ba~ed on the ~-ltht o~
the binder, o~ a sllleono re~in ~hleh i8 a
h-at curabl- struetur-d ~othylphenyl
poly8110xane r~o~n ha~ing
the repeatlng struetural ~or~ula
r ~ 1 r 3 1 r ~ 1 r
t Sl - O ~ Si - O ~ Sl - O ~ Sl - O
c~3 a X X X
~h-r~ln
- x 1~ a ruDctlonal group ~hleh allo~8
erw s-linkin~ at $t8 81te, and
a, ~, c, and d ar- posltl~o int-8ers
~hleh are surrlelently l~rge to
pro~lde tho resin, ~hen ~easured
~ .
at 60% resin sollds in xylen- at
25-C, ~lth a vl~co~lty o~ 30-50
contlpolse~, speclrlc gr~ity Or
1 03-1 2, and rerracti~e ind-x Or i~
1.45-1.57; and having
a ~llanol cont~nt abo~e 4~ bas-d on the
~elght Or the resln;
t2) 5-50% by l~elght, baaed on tho lelcht Or the
blnder, Or a rluorocarbon pol~er; nd
(3) 2-40% by ~elght, based on the ~elght o~ the
binder, Or an poxy re-ln ha~ing thc ror~ula
, . . .

10927~2
C}~2-\ C~2~-0-R-~-OCH2C C}I2~;0-~-R-~-OCH2-C~I-C~2
~horeln
n 18 ~n int-ger ~ro~ 0-42, and
R 1~ an alkylene group Or 1-4 carbon
ato~s;
(b) 0 2-10% by ~elght, based on the ~olght Or the
bind~r, Or a ~ilicon~ ~luld ~hich i8 a di~ethyl --
polyslloxane rluld havlng a vlsco~lty Or
50-5000 c~ntlstokes ~easured at 25C;
10(c) a rln~ly dl~ldod inorganlc hardoning agent in a
hardening agont to binder ratlo o~ about 5/100
to 400/100; and
(d) an inert llquld carrler
~ ~etal coo~ing ve~sel coat-d ~ith a cured
produeed ~ro~ the abo~e composltion i8 also part o~ the
inv~ntion
~SCRIPTIOII OF ~IIC~ IllVl!~TiOJ
The coating co~positlon o~ the inventlon
prererably has a relatlvely high solid~ content Or about
40-70% by ~-~ght in ~uitsble llquld carrler.
The ~ rorming binder con-tituent~ ~ro
dis~ol~-d ln organlc ol~ents ~uch ~ tolu~ne, xrl~ne,
tetralvaroruran, butyl CARBITOL*, cth~l~ne glycol ~onoethyl
ethcr, cthylene glycol ~onobu~yl ether, ana the like. -:
Th0 blnder o~ the novel Co~til~g compo~ltlon Or
the inveation i8 a blend Or a slllcone re~in which 1~
highl~ reactlve nethylph~nyl poly~ilo~ane resin, an epoxy
resin, and 8 rluorocarbo~ poly~ r
den~tes trade ~ark

~09274Z
The binder contains about 40-93% by weight of
silicone resin, 5-50% by weight of fluorocarbon polymer,
and 2-40% by weight of epoxy resin in amounts necessary
to equal 100%. Preferably, the binder contains 65-85%
by weight of silicone resin, 10-20% by weight of fluoro-
carbon polymer, and 5-15% by weight of epoxy resin.
Also present in the composition is a silicone
fluid which is a dimethyl polysiloxane. The amount of
dimethyl polysiloxane fluid utilized is based on the total
lO weight of binder. The amount of fluid will range from
0.2-10% by weight, based on the weight of the binder;
preferably, the xange will be l-3% by weight.
` A finely divided inorganic hardening agent is
used in the composition of the invention to provide a
finish having increased scratch resistance, abrasion
- resistance, hardness, blister resistance, and decreased
porosity. The hardening agent is added to the composition
in a ratio of hardening agent to binder of about 5/100
to about 400/100, preferably, about 10/100 to about
20 70/100, more preferably, 20/100-40/100.
The combination of these cornponents provides a
coating composition that adheres well to unprimed un-
treated substrates, and produces a flnish which may be llght
colored and has desireable thermal stability and release
properties.
The highly reactive methyl phenyl polysiloxane
resin is heat curable, has a silanol content above 4%,
preferably 5%, based on the weight of the resin and
has the repeating structural formula

- 109Z742
{~
CH3 X X c X d
~heraln
X 18 a functlonal group ~hleh allo~
eross-lin~ing at lts ~lte, and
a, b, c, and d aro po~itlve lntogers
~hlch are su~rlcl-ntly lar~e to
pro~ide the re~ln, ~hon nea~ured
at 60% rosin sollds ln xylone at
25-C, ~lth a V18CQ~lty Or 30-50
centlpoiscs, speclric gravlty Or
1.03-1.2~ and rerraetiv- ~ndex
1.45-1.57. ~; -
A partleularly prererred ~ethyl ph-nol polyslloxane
rc~ln ~h~n ~easurcd at 60% sollds ln xyleno at 25C, has a
v18c08ity Or about 35-45 centlpol~o, a speclrle ~ravlty Or
about 1.05-1.12, a r tractl~e index Or about 1.50-1.53, and
lt al~o has a so~tenln~ po~nt Or about 75-85~C-
The rluorocarbon poly~ers used in tho ¢omposltlon
~ ,,
Or th- in~e~tlon are ho~opoly~ers and copoly~ers (~ean~ng -
the poly~or contalns t~o or re alrrerent ~ono~er unlts)
Or ~onoethrlenlcally uAsaturatea hydrocarbon ~ono~er .;~
co~pletely substltuted ~lth rluorine ato~s or co~pletely
substitutod ~lth a co~binatlon Or rluorlne atoms and
ehlorino atoms. Included in thls group are perrluoroolerln
poly~ors such as polytotrarluoroethylene ~PTFS) snd . ~:
copolraers Or tetrarluorocthylene and hoxarluoropropylene
1A all ~ono~er unlt Yelght ratlos, rluorochlorocaibon
Bi
.. . . , ~ . . ...... ......... ... ... ... .. .

` 10~Z742
poly~ers ~uch as polymonochlorotrlrluoroethyl~n~, and
nor~lly solid copolymers Or tetrarluoro~thylene and
perrlu~roalkyl vlnyl ethers (~herein the alkyl troup i8
Or 1-5 carbon atoms) Mixtures Or these can also be used
A prererrcd rluoropolymer is a copoly~r Or
tetrarluoroeth~leno (TFE) copoly~erized ~ith either a
rluoroolerin or a perrluoro (alkyl vinyl ether)
When the TFE 1~ copolym~rized ~ith a rluoro-
olerln, the copoly~er ~111 contaln about 50-95~ by ~c~ht
Or TFE unlt, and about 50-5% by ~ei~ht Or hexa~luoro-
propylene or other sultable rluoroolerin havlng the rormula
CF2-CFY, ~herein Y i8 a Cl to C8 per~luoroslkyl radlc~l
Copolym~rs Or the type are descrlbed ln Unlted States
Patents 2,833,686 Or B W Sandt, ~hich lssued 1958 ~ay 6;
2,946,763 Or ~ I Bro and B W Sandt, whlch l~sued 1960
July 26; ant 3,085,083 Or B C Schrcyer ~hlch lssued 1963
April 9
Especl-lly u~erul 18 a tetrarluoroethylene/
hexarluoropropylone copolyoer ( Æ P). Preferably, hexa-
~luoropropylene (HFP) contont 18 bet~een about 6.75 and
about 27 ~ol~ht percent Or the copoly~er and more prererably
bet~een about 8 and about 18 ~elght pcrcent. These ~-
copoly~ers aro prepared by reacting TF~ and HFP 1~ an
aqueous system contalning a dlsper~lng agent and a rree
radlcal polymerl~atlon lnltlator according to procedures
disclosed ln Couture, Uhlted Stat-s Patent 3,132,12~.
Additlonally, the F~P copolyuer prererred 18 partlculate
an~ has a specirle ~elt vlscosity rrom 5- 60X104 pol#es,
ore prerer~bly 5- 25Xl04, and even more prererably 6-
lOX10 pols~s.
By the ter~ "sp~clrlc melt vlscoslty" as used
hereln, 18 meant the appareat melt vlsco~lty as measured
at 372C under a shear stre~s of 6.5 pound~ per #quare
B - 7 -
~ ' ~

~092742
inch. The values herein re~erred to are determlned uslng
a melt lndlcator Or the type described in the Americ~n
Soclety Or Tosting Materlals Test DL1238-57 T, modlfied
for corroslon re6istance to embody a cyllnder and orlfice
Or AMPCO* alumlnum bronze and a piston welghlng 60 grams,
havlng a STELLITE* cobalt-chromlum-tungston alloy tip.
The resln 18 charged to the 0.375-lnch I.D. cylinder
which 18 held at 372C + .5C, allowed to come to an
equillbrlum temperature during 5 minutes, and extruded
through the 0.0825-lnch dlameter, 0.315-lnch long orl~lce
under a plston loadlng Or 5,000 grams. The speclflc melt
vlscoslty ln polses 18 calculated as 53,150 divided by
the observed extrusion rate ln grams per mlnute.
The epoxy resin~ utillzed in the present lnven-
tlon are co~monly known in the art. One clas~ Or such
resins has the generalized rormula
CN2-CNC~ EO~ )-OCN2C CN~;;o-~>-R-~-ocN2-cN
~here n is an integer rrom 0-42 and R lB an alkylene group
o~ l-4 carbon atoms. The epo~y reslns utilized ln the
present lnventlon contain at least two epoxy groups per
molecule and, therefore, upon curing of the composltion,
introduce no uncross-linkable extractable portions into
the coating.
Prefer~bly, to obtain a coatlng wlth high gloss,
liquld epo~y resln i8 used. ~n undiluted liquid epoxy
resin where the average value Or n 18 about 0-3, R is
lsopropylidene, the viscoslty 18 1 . 2-225 poises at 25C
as measured by ASTM-DL445, and the epo~y equivalent is
* denotes trademark
-- 8 --
~A,

''~` la~742
l(
about 150-470 ls preferred. The epoxy equivalent l
defined as the grams of resin containlng l gram-equlvalent
of epoxide functionality as mea~ured by ASTM-D-1652. A
coating composition contalnlng EPON 828* 18 partlcularly
preferred because finishes produced by such compo~ltlons
have high gloss while maintalning high adheslon. EPON 828
is a liquid epoxy resin where the average value of n i~
about 0, R is isopropylidene, the viscosity of the un-
diluted resin is 100-160 poises at 25C as meaRured by
ASTM-D-~5, and the epoxy equivalent is 185-192.
Modificatlons of epoxy reslns can also be
utllized in the coating composition of the present inven-
tion. ~or example, it i8 known to those skilled in the
art that when an epoxy compound containing a hydroxy
group is brought in contact with an acid, there results
an ester or mixture of esters. Thus, when phosphoric
acid is added to an epoxy resin, a reactlon occuræ at one
or more of the epoxy groups of the molecule and the
resulting mixtuxe contains both the mono- and diesters of
phosphoric acid. A product of ~is reaction is exemplifled
by t~e formula
CR2-CH CR2-Eo-~-R-<~-o-cN2cR-cR2~o~o
n+l OH
These modified epoxy resins can still function as epoxy
resins in the coating compositions of the invention.
The dimethyl polyslloxane fluid utilized in the
coating composition of this invention can have a viscosity
of 0~65 to over a million centistokes measured at 25C,
.
but pre~erably~ haæ a viscosity of 100-5000 centistokes.
~`
* denotes trade mark
_ g _
~ , . .

109;;~742
To rnrm partlcularly high guality co~posltlon~, a Ylscoslty
Or 500-1500 centlstokes 18 pre~err-d Th- dl~ th~rl poly-
silo~ane rluld 18 a release agent ~hlch alds tho release
characterlstlcs Or tho rllma producod
The hardenlng agents that can be used ln the
co~posltion o~ this lnv~ntlon include zirconlu~ slllcate,
zirconiu~l oxlde, slllcon dloxlde, and reactlvo and
unr-actlve alumlnas l~xa~plos Or aluo~lnas which can be
used are calclned alu~nas, lol-soda alu~ina~, reactlve
10 alu~llnas, hlgh-purity alumina~, tabular alumlnas, calciu~
alu~illate co~ent, alld hydrated aluminas ~e prererred
hardenl~g ag~ts are reactlvo aluoli~a A prererr-d
reacti~o alu~lna whlch le usorul ln a coatlng co~posltlon
ha~ g exce~l-nt proportles 18 R~AC~lv~ A A-15S~
~hich is sold by Al¢oa mls alumina conslsts Or
A12C3 99- 5+f
~a2o . o8
S12 07
F~203 . 01;
20 lt, lrith co~pacti0n and sintering, can provldo an all-
a1U~1~ co~posltion with a green body denslty Or 2 86
a~/cc st 5000 p~l, and rired density of 3 93 gl~/CC. with
onl~r 10 1 porcent linear shrinkage arter one hour at
1665C
~ hen a reactive aludna i8 used as the hardenlng
agent, lts ratlo to binder 18 about 10/100 to about 70/100,
prc~erabl~r, 20/100 to 40/100
- Sultable llquid carriers include ~uch org~nlc
sQlv~nts as those used ~or dlssolvi~ the rll~-ro~ing
30 ~inder constltuents, ~or exa~ple, tolu~e, x~rl~e,
* denotes trade ~ark
- 10 -
1~

1 0 ~2~7~ 2
tetrahydroruran~ butyl CARBITOL, ethylene glycol monoethyl
ethor, ethJlene glycol ~onobutyl other, and the llko.
Optlonally, plgments (heat stable, riller or
reinrorcing plg~ent) can be u~ed in the coatlng co~posltlon
Or the lnvcntlon. A ratlo Or plg~ent to bind~r Or about
1/100-400/100 can bc utllized, prererably, about 1/100-
200/100, more pre~erabl~, ~n co~posltlon~ having excellent
proportie~, 1/100-50/100. Typlcal pigments that can be
used are, ror e~ample, carbon black, tltanium dloxide,
bro~n, black, and yello~ lron oxides, ~ica, talc, china
clay, ~etal po~ders, carbonates, potassiu~ titanate
~lbrlls, tltaniu~ dloxide rlbrlls, and the llko.
To ensure ~etting o~ the plg~ents and a stable
dlsperslon, ~etting agent ~y be added to the co~posltion
in a concentratlon Or 0.2-10% by ~olght bascd on the ~elght
Or the binder. ~etting agents uscrul are ~ctal salts,
partlcularly ~etal salts Or ratty acld~ such as zlnc
octoat~ and cobalt naphthenate. A prororred zinc octoate
18 ~uod~x~ (a zinc octoate ~olutlon ha~ing ô% z~nc ~ctal
cont~nt sold by Tenneco). A coupliAg solvent, such as
V.~. an~ P. ~aphtha, 18 someti~e~ used to ensure solubility
o~ the ~etting agent ~lthln the coating compositlon.
The coating compositlon Or this invention can
be prepared by Yarlous methods ~noun to the artisan. One
~ethod 18 to dls~olve the ~lllcone resln and wetting
agent ln suitable solvent, then blending the solutlon
~lth tho othor con~tltuents. Then the blend 18 ground
by conventlonal tochniques such as pebble mlll grinding,
ball ~11 grinding, sand mill grindlag, and tho llke.
The composltion Or this ln~entlon can be applled to

109274Z
a smooth substrate, which has been cleaned by solvent
wiping techniques, such as spraying, electrostatic
spraying, roller coating, and the like. If desired, the
sub6trate may be surface treated by such methods as frit
coating and grit blasting and a primer may be applied.
The composition is applied to the substrate to
a thickness of 0.2-5 mil (dry), preferably 0.5-1.5 mil
(dry), and is then baked for about 5-45 minutes at about
200-400C.
The coating composition of this invention forms
excellent finishes not only on cookware but also on ice
cube trays, dough cutters, paper cutters, and can be used
as a lubricant coating on bearing and curtain rods and
can be used as a coating on coin machine slots, fan vents,
shovels, and discardable aluminum utensils.
The following example illustrates the invention.
All quantities are on a weight basis unless otherwise
indicated.
EXAMPLE 1
A coating composition was prepared as follows:
~a) Preparing a resin solution by mixing until
dissolved:
Parts by
Weight
Silicone resin flake which
is a heat curable structured
methyl phenyl polysiloxane
resin having the repeating
structural formula
- 12 -

109~742
-~Sl-~Sl-~Sl-~
CH3 a X b X X
whereln
X i8 a runctlonal group
~hich allows cro~s-
linking at its slto, and
a, b, c and d are posi-
tlve integers which aro
surrlciently large to
pro~ldo the re~in, ~hen
~easured at 60~ resin
~ollds in xylene at 25C,
with a vlscoslty o~ 40
centlpolse, specl~ic
grarity Or 1.08, and
rerractive inde~ Or 1.518;
and a ~llanol contont above Part~ by
5~ based on tho woight ofWeight
the ro~ln. 80.00
- x~lene 80.00 -
V.~. and P. Naphtha 10.00
NuodexD (a ~inc octo~te 801u
tion containing 8% zinc
~etal, sold by Tenneco) 9-25
(b) adding the rollo~ing in order to the
product Or (a) and pebble grinding
for 21 hours:
sillcone rluid
(DC-200*, A polydi~ethyl
donotes trade mark
- 13 -
B
,- ~ . ~ .. . .

10~274Z
~iloxane having a vlscoslty of
1000 centistokes, sold by Dow
Cornlng) 2.0
tltanium dioxlde pigment 15.0
reactlve alumina
(A-15 SGD sold by Alcoa) 10.0
Teflon2 TE-9061- (a dry FEP flake
sold by E.I. du Pont de Nemours
and Company) 15.0
(c) adding, ln order, wlth stlrrlng to
Parts by
Welght
the product of (b) and then
mixing; EPON 828 (a liquld
epoxy resin sold by Shell
Chemlcal Company) 5.0
xylene 11.2
An aluminum muffin pan was wiped clean wlth acetone to
remoYe any resldue grea6e. m e above coatlng was then
sprayed onto the pan to a thickness of O.7 mil (dry), alr
dried for about 10 minutes and then baked for 7 minutes
at 325C. The resulting finish on the pan had a good
glossy appearance, excellent adhesion to smooth clean
aluminum, pencil hardness of HB-F, a light color, and
was fully cured as measured by a 50 double wipe test with
toluene. m e coated pan was sub~ected to a 25 bake test
at 220C with blueberry muffin mix and meat loaf mix.
After the test, the finishes release properties, ease of
cleaning, and appearance remained excellent.
- 14 - ~ ;
,
:... . .