Note: Descriptions are shown in the official language in which they were submitted.
21~630~
095/01~7 PCT~S94/06564
POWDER COATING COMPOSITIONS
This invention belongs to the field of powder
coatings. More particularly, this invention relates to
thermosetting powder coating compositions.
Plastic materials used in the manufacture of powder
coatings are classified broadly as either thermosetting
or thermoplastic. In the application of thermoplastic
powder coatings, heat is applied to the coating on the
substrate to melt the particles of the powder coating
and thereby permit the particles to flow together and
form a smooth coating.
Thermosetting coatings, when compared to coatings
derived from thermoplastic compositions, generally are
tougher, more resistant to solvents and detergents, have
b~etter adhesion to metal substrates and do not soften
when exposed to elevated temperatures. However, the
curing of thermosetting coatings has created problems in
obtaining coatings which have, in addition to the above-
stated desirable characteristics, good smoothness andflexibility. Coatings prepared from thermosetting
powder compositions, upon the application of heat, may
cure or set prior to forming a smooth coating, thereby
resulting in a relatively rough finish referred to as an
"orange peel" surface. Such a coating surface or finish
lacks the gloss and luster of coatings typically
obtained from thermoplastic compositions. The "orange
peel" surface problem has caused many to apply thermo-
setting coatings compositions from organic solvent
systems which are inherently undesirable because of the
environmental and safety problems that may be occasioned
by the evaporation of the solvent system. Solvent-based
coating compositions also suffer from the disadvantage
of relatively poor percent utilization; i.e., in some
modes of application, only 60 percent or less of the
WO95/01~7 PCT~S94/065 -
2~63~
-- 2 -
solvent-based coating composition being applied contacts
the article or substrate being coated. Thus, a
substantial portion of solvent-based coatings can be
wasted since that portion which does not contact the
article or substrate being coated obviously cannot be
easily reclaimed.
In addition to exhibiting good gloss, impact
strength and resistance to solvents and chemicals,
coatings derived from thermosetting coating compositions
must possess good to excellent flexibility. For
example, good flexibility is essential for powder
coating compositions used to coat sheet (coil) steel
which is destined to be formed or shaped into articles
used in the manufacture of various household appliances
and automobiles wherein the sheet metal is flexed or
bent at various angles.
All aliphatic polyesters such as those derived from
1,4-, 1,3- and 1,2-cyclohexanedicarboxylic acid (CHDA)
with 2,2,4,4-tetramethyl-1,3-cyclobutanediol or those
from CHDA and hydrogenated bisphenol A have excellent
weatherability. These resins can be made with Tg (glass
transition temperature) suitable for powder coatings.
Coatings from these resins, however, generally suffer
from poor flexibility and poor impact strength.
Powder coatings based on acrylic resins are known
to have excellent weathering performance but are
generally more expensive and impact strength and
flexibility are relatively poor.
British Patent 962,913 discloses polyesters
containing CHDA and 2,2,4,4-tetramethyl-1,3-cyclo-
butanediol useful as film and molding plastics.
U. S. Patent No. 3,313,777 describes polyesters
containing CHDA and 2,2,4,4-tetramethyl-1,3-cyclo-
butanediol useful as film and molding plastics.
U. S. Patent 4,363,908 discloses copolyesters
~ 095/01~7 ~1 C~3P~ 6 PCT~S94/06564
.. ..
-- 3 --
containing CHDA and 2,2,4,4-tetramethyl-1,3-cyclo-
butanediol useful as adhesives.
U. S. Patent 4,525,504 discloses stabilized
polyesters with improved weatherability based on CHDA
and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. These
polyesters are high molecular weight polyesters useful
in molding plastics.
U. S. Patent 4,910,292 discloses water-dissipatable
polyesters useful in coatings. 2,2,4,4-Tetramethyl-
1,3-cyclobutanediol is listed as a possible glycol
component.
U. S. Patent 5,097,006 and Research Disclosure, May
1990, Number 313, Publication No. 31336 describe an
aliphatic polyester derived from l,4-CHDA and a glycol
component comprised of cycloaliphatic diols; the
compositions are described as having improved weather-
ability.
This invention provides to thermosetting powder
coatings based on a blend of an amorphous aliphatic
reæin and a low Tg, aliphatic, semi-crystalline (sC)
resin. The SC resin significantly improves impact
strength while maintaining the excellent Q W weathering
properties of the aliphatic resins.
The amorphous resins are comprised of cyclohexane-
dicarboxylic acid (CHDA) and cycloaliphatic diols such
as 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 1,4-
cyclohexanediol, or hydrogenated bisphenol A~ The
amorphous resins preferably have a glass transition
temperature (Tg) of 50 to 70C and a hydroxyl or acid
number of 30 to about 80.
The SC aliphatic resins preferably have good
crystallinity and low Tg, such as one based on trans-
A 1,4-cyclohexanedicarboxylic acid and 1,4-butanediol.
Preferred SC resins have a Tm of 60-160C and a hydroxyl
35 or acid number of about 25-65.
WO95/01~7 PCT~S94/065 ~
216630~
It should be appreciated that in the compositions
of the present invention, when component (a) is
hydroxyl-functional, component (b) is preferably also
hydroxyl-functional; in such a case, conventional
crosslinkers are utilized. Conversely, when component
(a) is carboxyl-functional, component (b) is also
preferably carboxyl-functional; in such a case,
conventional crosslinkers for acid-functional systems
will be utilized. It is also within the scope of the
present invention that the binder portion of the
composition, i.e., components (a) and (b), may also be
comprised of a mixture of hydroxyl and carboxyl
functional; in other words, (a) may be hydroxyl-
functional and (b) may be carboxyl-functional, and vice-
versa. In such a case, the crosslinker will necessarilybe a blend of suitable crosslinkers appropriate to the
amounts of hydroxyl and carboxyl functionality present
in the system. As used herein, the terms "hydroxyl-
functional" and "carboxyl-functional" as used to
describe the blend of (a) and (b) or the composition, is
used in its ordinary art-recognized r~An;ng. In other
words, such terms denote whether the resin (or binder)
is predominantly carboxyl- or hydroxyl- functional in
character, thereby dictating the choice of crosslinker.
In such a case, for example, a hydroxyl functional resin
will have an acid number of less than about 15 and a
carboxyl functional resin will have a hydroxyl number of
less than about 15. The coating composition may be
based on hydroxyl resins and crosslinkers such as
blocked polyisocyanate, tetramethoxymethyl glycoluril or
melamine derivatives. Alternatively, the composition
may be comprised of a carboxyl resin and a crosslinker
such as triglycidylisocyanurate (TGIC) or an activated
~-hydroxylalkyl amide such as Bis(N,N-dihydroxy-
ethyl)adipamide. Optionally, additives such as benzoin,
095/01~7 ~ 3 p ~ PCT~S94/06564
-- 5 --
flow aids, pigments and catalyst may be used. Coatings
p~rovided by this invention maintain superior resistance
to Q W with improved impact and flexibility.
The present invention provides a thermosetting
coating composition comprising
(a) an amorphous polyester comprised of residues
of cyclohexanedicarboxylic acid and a cyclo-
aliphatic diol, said amorphous polyester
having a glass transition temperature (Tg) of
about 50C to 70C and a hydroxyl or an acid
number of about 30 to 80;
(b) a semicrystalline polyester comprised of
residues of cyclohexanedicarboxylic acid and a
linear diol, said linear diol having 4, 6, 8,
or 10 carbon atoms, said semicrystalline
polyester having a Tm of about 60-160C and a
hydroxyl or an acid number of about 30 to 80;
and
(c) a cross-linking effective amount of a cross-
linking agent.
As a further aspect of the present invention, there
is provided a thermosetting coating composition
comprising
(a) an amorphous polyester comprised of residues
of cyclohe~edicarboxylic acid and a cyclo-
aliphatic diol, said amorphous polyester
having a glass transition temperature (Tg) of
about 50C to 70C and a hydroxyl or an acid
number of about 30 to 80;
WO95/01~7 2 ~ ~ 6 3 ~ PCT~S94/065 -
(b) a semicrystalline polyester comprised of
residues of cyclohexanedicarboxylic acid and a
linear diol, said linear diol having 4, 6, 8
or 10 carbon atoms, said semicrystalline
polyester having a Tm of about 60-160C and a
hydroxyl or an acid number of about 30-80;
provided that when (a) has an acid number of
30 to 80, (b) has an acid number of 30 to 80,
and when (a) has a hydroxyl number of 30 to
80, (b) has a hydroxyl number of 30 to 80; and
(c) a cross-linking effective amount of a cross-
linking agent.
The powder coating compositions provided by the
present invention are useful in coating articles,
particularly metal articles, and upon curing provide
coatings possessing an excellent balance of weather-
ability and impact strength. The amorphous resins of
the above composition are preferably comprised of 1,4-,
1,3- and 1,2-cyclohexanedicarboxylic acid (CHDA) and
2,2,4,4-tetramethyl-1,3-cyclobutanediol; CHDA and
hydrogenated bisphenol A; or CHDA and 1,4-cyclo-
hexanediol. The resin may be modified with other
diacids or diols but must have Tg suitable for powder
coating compositions. The amorphous polyester resin
preferably has a number average molecular weight (Mn) of
from about 1,500 to about 10,000, most preferably from
about 2,000 to 6,000 and a glass transition temperature
(Tg) of preferably about 45C to 100C, most preferably
50 to 70C and hydroxyl or acid number of from about 20
to 100, preferably from about 30 to about 80, for cross-
linking.
The semi-crystalline resins of the compositions of
the present invention are preferably all aliphatic
O9S/01~7 6630 ~ PCT~S94l06564
resins which exhibit high crystallinity and low Tg. As
an especially preferred aspect of the present invention,
the semi-crystalline resin is one comprised of trans-
1,4-cyclohexanedicarboxylic acid and 1,4-butanediol with
optional slight modification with trimethylolpropane,
i.e., from about 0 weight percent to 12 weight percent,
based on the weight of the diol component. The
preferred aliphatic poly(tetramethylene-trans-1,4-
cyclohexanedicarboxylate) polyester of this invention
has a Tm of about 110-160C and a hydroxyl or acid
number in the range of about 25-65 and an inherent
viscosity of about 0.1 to 0.4. The semicrystalline
resin may also contain trimethylolpropane as branching
agent to adjust the crosslinking density as desired
depending on the crosslinker used.
The linear diol in component tb) herein denotes a
diol selected from the group consisting of 1,4-butane-
diol; 1, 6-hexanediol; 1, 8-oc~n~;ol; and 1, 10-
decanediol. Preferably, the linear diol is 1,4-butane-
diol or 1,6-hexanediol.
The relative amount of amorphous to crystalline
resin can be varied depending on factors such as each of
the resin's properties, the crosslinker employed, the
degree of pigment loading and the final coating
properties desired. Preferably, the amorphous resin
component will range from about 20 to about 80 weight
~percent based on the total weight percent of components
(a) and (b), and the semicrystalline resin will range
from about 80 to about 20 weight percent based on the
total weight percent of components (a) and (b). Most
preferably, components (a) and (b) will be present in
about a 1:1 (weight:weight) ratio.
Powder coating compositions of this invention may
be of course utilize different crosslinking chemistries
depending on the characteristics of components (a) and
WO95/01~7 PCT~S94/065 -
2~ 3a~
(b), i.e., whether the resin is predominantly hydroxyl
or the acid functional.
Examples of powder coating compositions from
hydroxyl resins are: (1) a polyurethane system made from
a hydroxyl functional resin and a polyisocyanate, (2) a
glycoluril system from a hydroxyl functional resin and a
glycoluril crosslinker such as tetramethoxymethyl
glycoluril or (3) a melamine system from a hydroxyl
functional resin and a melamine designed for powder
0 coating application. An example of a polyurethane
powder coating of this invention is comprised of:
(a) a blend of hydroxyl amorphous~semi-crystalline
polyesters described herein
(b) a blocked polyisocyanate crosslinker and,
(c) optionally, additives such as benzoin, flow
aids, pigments and catalyst.
The most readily-available, and thus the preferred,
blocked isocyanate cross-linking agents or compounds are
those commonly referred to as ~-caprolactam-blocked
isophorone diisocyanate, e.g., those described in U.S.
Patent Nos. 3,822,240, 4,150,211 and 4,212,962,
incorporated herein by reference. However, the products
marketed as ~-caprolactam-blocked isophorone diiso-
cyanate may consist primarily of the blocked,
difunctional, monomeric isophorone diisocyanate, i.e., a
mixture of the cis and trans isomers of 3-isocyanato-
methyl-3,5,5-trimethylcyclohexylisocyanate, the blocked,
difunctional dimer thereof, the blocked, trifunctional
trimer thereof or a mixture Ol the monomeric, dimeric
and~or trimeric forms. For example, the blocked poly-
isocyanate compound used as the cross-linking agent may
095/01~7 ~ PCT~S94/06564
be a mixture consisting primarily of the ~-caprolactam-
blocked, difunctional, monomeric isophorone diisocyanate
and the ~-caprolactam-blocked, trifunctional trimer of
isophorone diisocyanate. The description herein of the
cross-linking agents as "blocked isocyanates" refers to
compounds which contain at least two isocyanato groups
which are blocked with, i.e., reacted with, another
compound, e.g., ~-caprolactam. The reaction of the
i~ocyanato groups with the blocking compound is
reversible at elevated temperatures, e.g., normally
al~out 150C, and above, at which temperature the
isocyanato groups are available to react with the
hydroxyl groups present on the free hydroxy groups of
the polyester to form urethane linkages.
Alternatively, the blocked isocyanate may be a
cross-linking effective amount of an adduct of the 1,3-
diazetidine-2,4-dione dimer of isophorone diisocyanate
and a diol having the structure
2 0 OCN--R1~X--R1--NH--RC~R2{~_NH--R1~X--R1--NCO
5
wherein
R1 is a divalent 1-methylene-1,3,3-trimethyl-5-
cyclohexyl radical, i.e., a radical having the
structure
CH3~ ~.~
CH3~i ~ ~i
CH3 CH2-
R2 is a divalent aliphatic, cycloaliphatic,
araliphatic or aromatic residue of a diol; and
WO 95/01407 ~ 1 ~ 6 3 ~ ~ PCT/US94/065--
-- 10 --
X is a 1,3--diazetidine--2,4~ionediyl radical, i.e.,
a radical having the structure
wherein the ratio of NCO to OH groups in the forma--
tion of the adduct is about 1:0.5 to 1:0.9, the
mole ratio of diazetidinedione to diol is from 2:1
to 6:5, the content of free isocyanate groups in
the adduct is not greater than 8 weight percent and
the adduct has a molecular weight of about 500 to
4000 and a melting point of about 70 to 130C.
The adducts of the 1,3--diazetidine--2,4--dionedimer
of isophorone diisocyanate and a diol are prepared
according to the procedures described in U~S. Patent No.
4,413,079, incorporated herein by reference, by reacting
the diazetidine dimer of isophorone diisocyanate, prefer--
ably free of isocyanurate trimers of isophorone diiso--
cyanate, with diols in a ratio of reactants which gives
as isocyanto:hydroxyl ratio of about 1:0.5 to 1:0.9,
preferably 1:0.6 to 1:0.8. The adduct preferably has a
molecular weight of 1450 to 2800 and a melting point of
about 85 to 120C. The preferred diol reactant is 1,4--
butanediol. Such an adduct is commercially available
under the name Hiils BF1540.
The amount of the blocked isocyanate cross--linking
compound (or other crosslinker) present in the composi--
tions of this invention can be varied depending on
several factors such as those mentioned hereinabove
relative to the amount of components (a) and (b) which
are utilized. Typically, the amount of cross--linking
095/01407 ~ 6 63a ~ PCT~S94/06564
-- 11 --
compound which will effectively cross-link the polymers
to produce coatings having a good combination of
properties is in the range of about 5 to 30 weight
percent, preferably 15 to 25 weight percent, based on
the total weight of components (a) and (b).
An example of a glycoluril powder coating
composition of this invention is one comprised of:
(a) a blend of hydroxyl functional amorphous~semi-
crystalline polyester resin described above;
(b) a crosslinking agent from the glycolurilfamily of "aminoplast" crosslinking agents,
such as tetramethoxymethyl glycoluril
commercially available as POWDERLINK 1174 from
American Cyanamid; and
(c) optionally a catalyst such as toluenesulfonic
acid or methyltolyl sulfonimide.
Examples of powder coating compositions prepared
from carboxyl functional resins are; (1) a weatherable
epoxy system such as a TGIC (triglycidylisocyanurate)
system and (2) the activated ~-hydroxylalkyl amide-based
system. An example of an epoxy system is:
(a) a carboxyl functional amorphous~ semi-
crystalline polyester blend described above,
and as crosslinker,
(b) a weatherable epoxy such as triglycidyl-
isocyanurate (TGIC) commercially available as
ARALDITE PT-810 sold by Ciba Geigy, or
alternatively, an acrylic resin cont~;n;ng
pendant reactive epoxy functional groups, such
WO9~/01~7 PCT~S94/065 ~
~,~,6~30G
as the glycidyl group, e.g., glycidyl
methacrylate polymer available from S.C.
Johnson as PD 7610.
An example of an activated ~-hydroxylalkyl amide
system is:
(a) a carboxyl functional amorphous~ semi-
~ cryst~ll;ne polyester blend described a~ove,
(b) an activated ~-hydroxylalkyl amide such as
Bis(N,N-dihydroxyethyl)adipamide commercially
available from Rohm and Haas as PRIMID XL552.
In the activated ~-hydroxylalkyl amide system
above, it is further preferred that a catalyst comprised
of a carboxylate salt of a metal such as zinc, aluminum,
or titanium, or an oxide of aluminum or zinc is present.
Especially preferred as a catalyst is zinc stearate.
Further description of catalyst systems for an activated
~-hydroxylalkyl amide system can be found in U.S.
Application Seral No. 08~084,104, filed on this date,
incorporated herein by reference.
As noted above, components (a) and (b) may be a
mixture of carboxyl and hydroxyl functional resins.
Thus, in a further preferred em~odiment of the present
invention, there is provided a thermosetting coating
composition comprising a blend comprising
(a) an amorphous polyester comprised of residues
of cyclohexanedicarboxylic acid and a cyclo-
aliphatic diol, said amorphous polyester
having a glass transition temperature (Tg) of
about 50C to 70C and a hydroxyl or an acid
number of about 30 to 80;
E SHE~ (R ~ ~6
095/01~7 21 ~63 PCT~S94/06564
- 13 -
(b) a semicrystalline polyester comprised of
residues of cyclohexanedicarboxylic acid and a
linear diol, said linear diol having 4, 6, 8,
or 10 carbon atoms, said semicrystalline
polyester having a Tm of about 60-160C and a
hydroxyl or an acid number of about 30 to 80;
provided that when (a) has an acid number of
30 to 80, (b) has an acid number of 30 to 80,
and when (a) has a hydroxyl number of 30 to
80, (b) has a hydroxyl number of 30 to 80; and
(c) a cross-linking effective amount of a cross-
linking agent.
The 1,4-CHDA used for the preparation of the resin
which is labeled "CA" in the experimental section below
has a cis~trans ratio of about 60~40. Dimethyl trans-
1,4-cyclohPxAnedicarboxylate, which has a trans isomer
of at least 70% is used for the preparation of the
resins labeled "CC" and "HC" in the experimental
section.
The powder coating compositions of this invention
may be prepared from the compositions described herein
by dry-mixing and then melt-blending components (a) and
(b~l and the cross-linking compound, optionally a cross-
linking catalyst, along with other additives commonly
used in powder coatings, and then grinding the
solidified blend to a particle size, e.g., an average
particle size in the range of about 10 to 300 microns,
suitable for producing powder coatings. For example,
the ingredients of the powder coating composition may be
dry blended and then melt blended in a Brabender
extruder at 90 to 130C, granulated and finally ground.
The melt blending should be carried out at a temperature
sufficiently low to prevent the unblocking of the
WO95/01~7 PCT~S94/065 ~
21~3~
- 14 -
polyisocyanate cross-linking compound and thus avoiding
premature cross-linking.
The powder coating compositions preferably contain
a flow aid, also referred to as flow control or leveling
agents, to enhance the surface appearance of cured
coatings of the powder coating compositions. Such flow
aids typically comprise acrylic polymers and are avail-
able from several suppliers, e.g., Modaflow from
Monsanto Company and Acronal from BASF. Other flow
control agents which may be used include Modarez MFP
available from Synthron, EX 486 available from Troy
Chemical, BYK 360P available from BYK Mallinkrodt and
Perenol F-30-P available from Henkel. An example of one
specific flow aid is an acrylic polymer having a
molecular weight of about 17,000 and containing 60 mole
percent 2-ethylhexyl methacrylate residues and about 40
mole percent ethyl acrylate residues. The amount of
flow aid present may preferably be in the range of about
0.5 to 4.0 weight percent, based on the total weight of
the resin component, and the cross-linking agent.
The powder coating compositions may be deposited on
various metallic and non-metallic (e.g., thermoplastic
or thermoset composite) substrates by known techniques
for powder deposition such as by means of a powder gun,
by electrostatic deposition or by deposition from a
fluidized bed. In fluidized bed sintering, a preheated
article is immersed into a suspension of the powder
coating in air. The particle size of the powder coating
composition normally is in the range of 60 to 300
microns. The powder is maintained in suspension by
passing air through a porous bottom of the fluidized bed
chamber. The articles to be coated are preheated to
about 250 to 400F (about 121 to 205C) and then
brought into contact with the fluidized bed of the
powder coating composition. The contact time depends on
O9~/01~7 6630~ PCT~S94/06564
- 15 -
the thickness of the coating that is to be produced and
typically is from 1 to 12 seconds. The temperature of
the substrate being coated causes the powder to flow and
thus fuse together to form a smooth, uniform,
continuous, uncratered coating. The temperature of the
preheated article also effects cross-linking of the
coating composition and results in the formation of a
tough coating having a good combination of properties.
Coatings having a thickness between 200 and 500 microns
may be produced by this method.
The compositions also may be applied using an
electrostatic process wherein a powder coating composi-
tion having a particle size of less than 100 microns,
preferably about 15 to 50 microns, is blown by means of
compressed air into an applicator in which it is charged
with a voltage of 30 to 100 kV by high-voltage direct
current. The charged particles then are sprayed onto
the grounded article to be coated to which the particles
adhere due to the electrical charge thereof. The coated
article is heated to melt and cure the powder particles.
Coatings of 40 to 120 microns thickness may be obtained.
Another method of applying the powder coating
compositions is the electrostatic fluidized bed process
which is a combination of the two methods described
above. For example, annular or partially annular
electrodes are mounted in the air feed to a fluidized
bed so as to produce an electrostatic charge such as 50
to 100 kV. The article to be coated, either heated,
e.g., 250O to 400F, or cold, is exposed briefly to the
fluidized powder. The coated article then can be heated
to effect cross-linking if the article was not preheated
to a temperature sufficiently high to cure the coating
upon contact of the coating particles with the article.
The powder coating compositions of this invention
may be used to coat articles of various shapes and sizes
WO95/01~7 216 6 3 0 ~ PCT~S94/065 -
- 16 -
constructed of heat-resistance materials such as glass,
ceramic and various metal materials. The compositions
are especially useful for producing coatings on articles
constructed of metals and metal alloys, particularly
steel articles. As noted above, since the compositions
provided by the present invention cure at temperatures
as low as 115C, it is also possible to coat many
thermoplastic and thermosetting resin compositions with
the compositions of the present invention.
Further examples of formulation methods, additives,
and methods of powder coating application may be found
in User's Guide to Powder Coatin~, 2nd Ed., Emery
Miller, editor, Society of Manufacturing Engineers,
Dearborn, (1987).
The compositions and coatings of this invention are
further illustrated by the following examples.
Experimental Section
.
The inherent viscosity (I.V.), in dl~g were
determined in phenol~tetrachloroethane (60~40 w~w) at a
concentration of 0.5g~100 ml.
The resin melt viscosity, in poise, were determined
using an ICI melt viscometer at 200C.
The acid number and hydroxyl number were determined
by titration and reported as mg of KOH consumed for each
gram of resin.
The glass transition temperature (Tg), was
determined by differential scAnning calorimetry (DSC) on
the second heating cycle s~n~;ng at 20C~minute after
the sample has been heated to melt and quenched to below
the resin Tg. Tg values are reported as midpoint.
The weight average mol~c~l] A~ weight (Mw) and number
average molecular weight (Mn) are determined by gel
permeation chromatography in tetrahydrofuran (THF) using
~ 095/01~7 PCT~S94/06564
21 ~3~
- 17 -
polystyrene standard and a W detector.
Impact strengths are determined using a Gardner
Laboratory,Inc., impact tester per ASTM D 2794-84.
Pencil hardness is determined using ASTM D 3363-74.
The hardness is reported as the hardest pencil which
will not cut into the coating. The results are
expressed according to the following scale:
(softest)6B,5B,4B,3B,2B,B,HB,F,H,2H,3H,4H,5H,6H
(hardest).
The conical mandrel is performed using a Gardener
Laboratory Inc., conical mandrel of specified size
according to ASTM-522.
The 20 and 60 degree gloss are measured using a
gloss meter (Gardener Laboratory, Inc. Model GC-9095)
according to ASTM D-523.
The Q W resistance is measured by the loss of
gloss. Q W is run by alternately exposing the coated
panel at 70C to a 313 nm fluorescent tube for 8 hours
followed by a condensation at 45C for 4 hours. Gloss
is monitored every loo hours of exposure. The number of
hours needed to reduce the 60O gloss to 50% of the
original is reported.
Carboxyl Resins
Carboxyl Resin CA
To a 1000 ml, 3-neck round bottom flask were added
2,2,4,4-tetramethyl-1,3-cyclobutanediol (204.5 g, 1.418
moles), 2,2-dimethyl-1,3-propanediol (66.1 g, 0.635
moles), trimethylolpropane (8.5 g, 0.063 moles) and
Fascat 4100 (0.6 g). The contents were heated to melt
at 180C and 1,4-cyclohexanedicarboxylic acid (328.2 g,
1.~08 moles) is added. The flask was swept with 1.0
scfh nitrogen while the temperatures was raised from
WO95/01~7 PCT~S94/065 0
~6~3Q~ _ 18 -
180C to 230C over a 6-hour period. The batch
temperature was maintained at 230C for 8 hours. The
resulting resin has an acid number of 3 mg KOH~g and an
ICI melt viscosity of 15 poise at 200C. 1,4-Cyclo-
hexanedicarboxylic acid (70.0 g) is added at 230C and
the melt was agitated at 230C for 4 hours. The molten
resin was poured to a syrup can where it cooled to a
solid with the following properties:
I.V. 0.237 dl~g
ICI Melt Viscosity at 200C 52 poise
Acid Number 37
Hydroxyl Number 3
DSC (2nd cycle)
Tg 58C
Gel permeation chromatography
Mw 11,047
Mn 3,308
Carboxyl Resin CB
To a 3000 ml, 3-neck round bottom flask were added
hydrogenated bisphenol A (726.5 g, 3.027 moles), 2,2-
dimethyl-1,3-propanediol (326.4 g, 2.847 moles) and
trimethylolpropane (24.3 g, 0.183 moles) and FASCAT 4100
(1.8 g). The contents were heated to melt at 180C.
1,4-cyclohP~Anedicarboxylic acid (951.7 g, 5.526 moles)
was added. The flask was swept with 1.0 scfh nitrogen
while the temperatures was raised from 180C to 230C
over a 6-hour period. The batch temperature was
maintained at 230C for 8 hours. The resin has an acid
number of 3 mg KOH~g and an ICI melt viscosity of 15
poise at 2rooc. 1,4-Cyclohexanedicarboxylic acid
(238.2 g) was added at 230C and the melt agitated at
230C for 4 hours. The molten resin was poured to a
~ 95/01~7 21 6 63o ~ PCT~S94/06564
-- 19 --
syrup can where it cooled to a solid with the following
properties:
I.V. 0.174 dl~g
ICI Melt Viscosity at 200C 31 poise
~cid Number 47
~ydroxyl Number 5
iDSC (2nd cycle)
Tg 60C
~el permeation chromatography
Mw 6,263
Mn 1,904
Carboxyl Resin CC
This example illustrates the typical procedure for
preparing the all-aliphatic semi-crystalline polyester
of this invention.
A 3000 mL, 3-necked, round bottom flask equipped
wit:h a stirrer, a short distillation column, and an
inlet for nitrogen, was charged with dimethyl cyclo-
hexanedicarboxylate (1280.8 g, 6.40 mol), 1,4-butanediol
(692.9g 7.683 mol, 10% excess), and 100 ppm of titanium
tet:raisopropoxide in 2-propanol. The flask and contents
were heated under nitrogen atmosphere to a temperature
of 170C at which point methanol begins to distill
rapidly from the flask. After the reaction mixture was
heated with stirring at this temperature for about 1
hour, the temperature was increased to 200C for 2
- hours, raised to 215C for 4 hours, and then to 235C.
After 3 hours at this temperature, a vacuum of 10 mm of
mercury was applied over a period of 12 minutes.
Stirring was continued under 10 mm of mercury at 235C
for about 3 hours to produce a low melt viscosity,
WO95/01~7 ~ ~ 6 3 ~ PCT~S94/065
- 20 -
colorless polymer. The resulting polymer was cooled to
200C and 1,4-cyclohexanedicarboxylic acid (2Z8.7 g,
1.33 mol) was added. Heating with stirring was
continued for about 4 hours to produce a resin with an
inherent viscosity of 0.21, a melting point of 134C, an
acid number of 47, and a molecular weight by GPC of
2200.
Example Powder lA - Powder Coating from 70~30 Resin
CA~CC and ~-hydroxylalkylamide
-
This example provides a coating with excellent W
resistance and excellent impact resistance.
Carboxyl Resin CA (260 g), Resin CC (112 g), PRIMID
XL552 (28.0 g), MODAFLOW 2000 (6.0 g), benzoin (1.0 g),
llNUVlN 144 (6.0 g), TIN~VIN 234 (6.0 g), and titanium
dioxide (200.0 g) were mixed in a Vitamix mixer and
compounded in an APV extruder at 130C. The extrudate
was cooled, granulated, and pulverized in a Bantam mill
with liquid nitrogen bled into the grinding chamber.
The powder was classified through a 200 mesh screen.
The powder was electrostatically applied to a 3 in. x 9
in. metal panel and cured in a 350F oven for 20
minutes. The film properties are as follows:
~ 095/01~7 - PCT~S94/06564
21 66306
- 21 -
Film thickness, Mil 2.2
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness F
Gloss
20 deg 57
60 deg 86
iMEK double rubs more than 200
~ W , hours to 50% loss >2300 hrs.
Example Powder 2A - Powder Coating from 50~50 Resin
CA~CC and ~-hydroxylalkylamide
This example provides a coating with excellent W
resistance and excellent impact.
Resin CA (186 g), resin CC (186 g), PRIMID XL552
(28.0 g), MODAFLOW 2000 (6.0 g), benzoin (1.0 g),
TIN W IN 144 (6.0 g), 'l'lNUVlN- 234 (6.0 g), and titanium
dioxide (200.0 g) were mixed in a Vitamix mixer and
compounded in an APV extruder at 130C. The extrudate
was cooled, granulated, and pulverized in a Bantam mill
with liquid nitrogen bled into the grinding chamber.
The powder was classified through a 200 mesh screen.
The powder was electrostatically applied to a 3 in. x 9
in. metal panel and cured in a 350F oven for 20
minutes. The film properties are as follows:
WO9~/01~7 2 ~ 6 6 3 ~ ~ PCT~S94/065 ~
Film thickness, Mil 2.2
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness HB
Gloss
20 deg 47
60 deg 81
MEK double rubs more than 200
Q W, hours to 50% loss 1600
Example Powder 3B - Powder Coating from 70~30 Resin
CB~CC and ~-hydroxylalkylamide
This example provides a coating with excellent W
resistance and excellent impact.
Resin CB (260 g), Resin CC (112 g), PRIMID XL552
(28.0 g), MODAFLOW 2000 (6.0 g), benzoin (1.0 g),
'l'lNUVl~ 144 (6.0 g), l'lNUVl~ 234 (6.0 g), and titanium
dioxide (200.0 g) were mixed in a Vitamix mixer and
compounded in an APV extruder at 130C. The extrudate
was cooled, granulated, and pulverized in a Bantam mill
with liquid nitrogen bled into the grinding chamber.
The powder was classified through a 200 mesh screen.
The powder was electrostatically applied to a 3 in. x 9
in. metal panel and cured in a 375F oven for 20
minutes. The film properties are as follows:
095/01~7 ~ 21 ~ PCT~S94/06564
- 23 -
Film thickness, Mil 2.3
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness HB
Gloss
20 deg 62
60 deg 88
MEK double rubs more than 200
Q W, hours to 50% loss >2600
Example Powder 4B - Powder Coating from 50~50 Resin
CB~CC and ~-hydroxylalkylamide
This example provides a coating with excellent W
resistance and excellent impact.
Resin CB (186 g), Resin CC (186 g), PRIMID XL552
(28.0 g), MODAFLOW 2000 (6.0 g), benzoin (1.0 g),
TIN WIN 144 (6.0 g), 'l'lNUVlN 234 (6.0 g), and titanium
dioxide (200.0 g) were mixed in a Vitamix mixer and
compounded in an APV extruder at 130C. The extrudate
was cooled, granulated, and pulverized in a Bantam mill
with liquid nitrogen bled into the grinding chamber.
The powder was classified through a 200 mesh screen.
The powder was electrostatically applied to a 3 in. x 9
i]~. metal panel and cured in a 350F oven for 20
m:inutes. The film properties are as follows:
WO95/01~7 2 ~ ~ & ~ ~ & PCT~S94/065 ~
- 24 -
Film thickness, Mil 2.0
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness 2B
Gloss
20 deg 47
60 deg 83
MEK double rubs more than 200
Q W , hours to 50% loss 1900
Comparative Example 5A - Powder Coating from Resin CA
and ~-hydroxylalkylamide
This comparative example provides a coating with
excellent UV resistance but poor impact.
Resin CA (372 g), PRIMID XL552 (28.0 g), MODAFLOW
2000 (4.0 g), benzoin (1.0 g), l'lNUVlN- 144 (6.0 g),
'l'lNUVl~ 234 (6.0 g), and titanium dioxide (200.0 g) were
mixed in a Vitamix mixer and compounded in an APV
extruder at 130C. The extrudate was cooled,
granulated, and pulverized in a Bantam mill with liquid
nitrogen bled into the grinding chamber. The powder was
classified through a 200 mesh screen. The powder was
electrostatically applied to a 3 in. x 9 in. metal panel
and cured in a 325F oven for 20 minutes. The film
properties are as follows:
~ 095/01~7 21 ~30 ~ PCT~S94/06564
- 25 -
Film thickness, Mil 2.2
Impact strength, (in.~lb)
Front 40
Reverse 20
Pencil Hardness H
Gloss
20 deg 68
60 deg 89
MEK double rubs 200
Q W, hours to 50% loss 2200
Comparative Example 6B - Powder Coating from Resin CB
and ~-hydroxylalkylamide
This comparative example provides a coating with
excellent W resistance but poor impact (40~20
front~reverse).
Carboxyl Resin CB (372 g), PRIMID XL552 ~28.0 g),
M~DAFLOW III (6.0 g), benzoin (1.0 g), TINUVIN 144 (6.0
g), 'l'lNUVlN 234 (6.0 g), and titanium dioxide (200.0 g)
were mixed in a Vitamix mixer and compounded in an APV
extruder at 130C. The extrudate was cooled,
granulated, and pulverized in a Bantam mill with liquid
nitrogen bled into the grinding chamber. The powder was
classified through a 200 mesh screen. The powder was
el,ectrostatically applied to a 3 in. x 9 in. metal panel
an~ cured in a 375CF oven for 20 minutes. The film
pr~perties are as follows:
WO95/01407 ~ 3 o ~ PCT~S94/065
- 26 -
Film thickness, Mil 2.0
Impact strength, (in.~lb)
Front 40
Reverse 20
Pencil Hardness F
Gloss
20 deg 72
60 deg 88
MEK double rubs 200
Q W , hours to 50% loss >1600
Comparative Example 7 - Powder Coating from Commercial
Rucote 915 and ~-hydroxyl-
alkylamide
This comparative example shows that aromatic resin
has fair impact but poor W resistance.
Carboxyl resin RUCOTE 915 (379.0 g), PRIMID XL552
(21.0 g), MODAFLOW III (4.0 g), benzoin (1.0 g), ~l~lNUVlN-
144 (6.0 g), TIN W IN 234 (6.0 g), and titanium dioxide
(200.0 g) were mixed in a Vitamix mixer and compounded
in an APV extruder at 130C. The extrudate was cooled,
granulated, and pulverized in a Bantam mill with liquid
nitrogen bled into the grin~;ng chamber. The powder was
classified through a 200 mesh screen. The powder was
electrostatically applied to a 3 in. x 9 in. metal panel
and cured in a 325F oven for 20 minutes. The film
properties are as follows:
~ 095/01~7 ~166306 PCT~S94/06564
- 27 -
Film thickness, Mil 2.0
= Impact strength, (in.~lb)
Front 40
Reverse 80
Pencil Hardness F
Gloss
20 deg 78
60 deg 95
MEK double rubs 200
Q W, hours to 50% loss 230
Comparative Example 8 - Powder Coating from Commercial
Resin EMS GRILESTA 7612 and
~-hydroxyalkylamide
This comparative example shows that aromatic resin
has good impact but poor W resistance.
Carboxyl resin EMS GILESTA 7612 (379.0 g), PRIMID
XL552 (21.0 g), MODAFLOW III ( 4.0 g), benzoin (1.0 g),
TIN W IN 144 (6.0 g), l'lNUVlN- 234 (6.0 g), and titanium
dioxide (200.0 g) were mixed in a Vitamix mixer and
compounded in an APV extruder at 130C. The extrudate
was cooled, granulated, and pulverized in a Bantam mill
with liquid nitrogen bled into the grinding chamber. The
powder was classified through a 200 mesh screen. The
powder was electrostatically applied to a 3 in. x 9 in.
me~al panel and cured in a 350F oven for 20 minutes.
The film properties are as follows:
-
WO95/01~7 2 1 6 ~ 3 ~ PCT~S94/065 -
- 28 -
Film thickness, Mil 21.1
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness H
Gloss
20 deg 73
60 deg 92
MEK double rubs 200
Q W , hours to 50% loss 250
Comparative Example 9 - Powder Coatings from Carboxyl
Resin EMS GRILESTA 7309 and TGIC
This example shows aromatic resin with TGIC has
good impact but poor W resistance.
Carboxyl EMS GILESTA 7309 (372.0 g), Triglycidyl-
isocyanurate (TGIC) (28.0 g), MODAFLOW III (4.0 g),
benzoin (1.0 g), TINUVIN 144 (5.6 g), 'l'lNUVlN- 234
(5.6 g), and titanium dioxide (160.0 g) were mixed in a
Vitamix mixer and compounded in an APV extruder at
130C. The extrudate was cooled, granulated, and
pulverized in a Bantam mill with liquid nitrogen bled
into the grinding chamber. The powder was classified
through a 200 mesh screen. The powder was electro-
statically applied to a 3 in. x 9 in. metal panel and
cured in a 350F oven for 20 minutes. The film
properties are as follows:
095tO1~7 ~ ~ PCT~S94/06564
- 29 -
Film thickness, Mil 1.9
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness H
Gloss
20 deg 63
60 deg 82
MEK double rubs 200
Q W, hours to 50% loss 250
HYdroxYl Resins
Hydroxyl Resin HA
To a 1000 ml, 3-neck round bottom flask were added
2,2,4,4-tetramethyl-1,3-cyclobutanediol (209.0 g, 1.450
moles), 2,2-dimethyl-1,3-propanediol (36.1 g, 0.347
moles), trimethylolpropane (18.1 g, 0.135 moles) and
FASCAT 4100 (0.5 g). The contents were heated to melt
at 180C and 1,4-cyclohexanedicarboxylic acid (306.5 g,
1.780 moles) is added. The flask was swept with 1.0
scfh nitrogen while the temperatures was raised from
180C to 230C over a 6-hour period. The batch
temperature was maintained at 230C for 8 hours. The
molten resin was poured to a syrup can where it cooled
to a solid with the following properties:
WO95/01407 2 ~ ~ 6 3 0 6 PCT~S94/065 -
- 30 -
I.V. 0.249
ICI Melt Viscosity at 200C poise
Acid Number 2.6
Hydroxyl Number 28.0
DSC (2nd cycle)
Tg 49C
Gel permeation chromatography
Mw 19,841
Mn 4,750
Hydroxyl Resin HB
To a 1000 ml, 3-neck round bottom flask were added
2,2,4,4-tetramethyl-1,3-cyclobutanediol (209.0 g, 1.450
moles), 2,2-dimethyl-1,3-propanediol (40.2 g, 0.387
moles), trimethylolpropane (12.7 g, 0.095 moles) and
Fascat 4100 (0.5 g). The content was heated to melt at
180C and 1,4-cyclohexanedicarboxylic acid (307.2 g,
1.784 moles) was added. The flask was swept with 1.0
scfh nitrogen while the temperatures was raised from
180C to 230C over a 6-hour period. The batch
temperature was maintained at 230C for 8 hours. The
molten resin was poured to a syrup can where it cooled
to a solid with the following properties:
095/01~7 ~ ~ ~ PCT~S94/06564
I.V. 0.233
ICI Melt Viscosity at 200C poise
Acid Number 3.4
Hydroxyl Number 42.4
DSC (2nd cycle)
Tg 47C
Gel permeation chromatography
Mw 16,233
Mn 3,806
Hydroxyl Resin HC
This example illustrates the typical procedure for
preparing the aliphatic semi-crystalline polyesters of
this invention which are in this example,
hydroxyl-functional. A 3000 mL, 3-necked, round-bottom
flask equipped with a stirrer, a short distillation
column, and an inlet for nitrogen, was charged with
dimethyl cyclohexanedicarboxylate (1259.7 g, 6.29 mol),
1,4-butanediol (997.5 g, 11.08 mol), trimethylolpropane
(73.9 g, 0.55 moles) and 10 mL of titanium tetraiso-
propoxide~2-propanol solution (100 ppm Ti). The flask
and contents were heated under nitrogen atmosphere to a
temperature of 170C at which point methanol began to
distill rapidly from the flask. After the reaction
mixture was heated with stirring at this temperature for
about 1 hour, the temperature was increased to 200C for
2 hours, raised to 215C for 4 hours, and then to 235C.
After 3 hours at this temperature, a vacuum of 10 mm of
mercury was applied over a period of 18 minutes.
Stirring was continued under 10 mm of mercury at 235C
for about 3 hours to produce a low melt viscosity,
colorless polymer. The polymer has an inherent
viscosity of 0.30, a melting point of 130C, and a
hydroxyl number of 30.
WO95/01~7 - 32 - PCT~S94/065 -
Example Powder 10A - Powder Coating from 50~50 Resin
HA~HC and ~-caprolactam Blocked
Isophoronediisocyanate
This example provides a coating with excellent W
resistance and excellent impact.
Resin HA (160 g), Resin HC (160 g), Huls BF 1540
(80.0 g), benzoin (6.0 g), MODAFLOW 2000 (6.0 g),
'l'l~UVl~ 144 (6.0 g), l'l~UVl~ 234 (6.0 g), and titanium
dioxide (160.0 g) were mixed in Vitamix mixer and
compounded in an APV extruder at 125C. The extrudate
was cooled, granulated, and pulverized in a Bantam mill
with liquid nitrogen bled into the grinding chamber.
The powder was classified through a 200 mesh screen.
The powder was electrostatically applied to a 3 in. x 9
in. metal panel and cured in a 350F oven for 20
minutes. The film properties are as follows:
Film thickness, Mil 1.8
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness B
Gloss
20 deg 67
60 deg 92
MEK double rubs more than 200
Q W , hours to 50% loss >2300
Example Powder llA - Powder Coating from 50~50 Resin
HA~HC and Self-blocked
Isophoronediisocyanate
This example provides a coating with excellent W
resistance and excellent impact.
Resin HA (160 g), Resin HC (160 g), Huls BF 1540
O95/01~7 l ~oO PCTl594/06564
(80.0 g), benzoin (6.0 g), MODAFLOW 2000 (6.0 g),
- TXN W IN 144 (6.0 g), TIN W IN 234 (6.0 g), and titanium
dioxide (160.0 g) were mixed in Vitamix mixer and
compounded in an APV extruder at 125C. The extrudate
was cooled, granulated, and pulverized in a Bantam mill
with liquid nitrogen bled into the grinding chamber.
The powder was classified through a 200 mesh screen.
The powder was electrostatically applied to a 3 in. x 9
in. metal panel and cured in a 375F oven for 20
minutes. The film properties are as follows:
Film thickness, Mil 1.8
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness B
Gloss
20 deg 63
60 deg 89
MEK double rubs more than 200
Q W , hours to 50% loss >1500
Example Powder 12A - Powder Coating from 50~50 Resin
HB~HC and POWDT~RTTNR 1174
Crosslinker
Resin HB (188 g), Resin HC (188 g), POWDERLINK 1174
(24.0 g), methyl tolyl sulfonimide (5.0 g), benzoin (6.0
g), MODAFLOW 2000 (6.0 g), l'lNUVlN- 144 (6.0 g), l'lNUVlN
234 (6.0 g), and titanium dioxide (160.0 g) were mixed
in Vitamix mixer and compounded in an APV extruder at
125C. The extrudate was cooled, granulated, and
pulverized in a Bantam mill with liquid nitrogen bled
WO95/01~7 216 6 3 ~ ~ PCT~S94/065 ~
- 34 -
into the grinding chamber. The powder was classified
through a 200 mesh screen. The powder was elec~ro-
statically applied to a 3 in. x 9 in. metal panel and
cured in a 350F oven for 20 minutes. The film
properties are as follows:
Film thickness, Mil 1.9
Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness 2B
Gloss
20 deg 40
60 deg 85
MEK double rubs more than 200
Q W, hours to 50% loss >1500
Comparative 13A - Powder Coatings from Resin HA and
Caprolactam Blocked
Isophoronediisocyanate
This comparative shows that Resin HA produces
coating with excellent Q W but poor impact.
Resin HA (415 g), Huls 1530 (99.4 g), dibutyltin
dilaurate (5.1 g), benzoin (5.1 g), MODAFLOW III (7.7
g), 'l'lNUVl~ 144 (5.1 g), 'l'lNUVlN 234 (5.1 g), and
titanium dioxide (205.7 g) were mixed in a Vitamix mixer
and compounded in an APV extruder at 120C. The
extrudate was cooled, granulated, and pulverized in a
Bantam mill with liquid nitrogen bled into the grinding
chamber. The powder was classified through a 200 mesh
screen. The powder was electrostatically applied to a 3
in. x 9 in. metal panel and cured in a 400F c~en for 10
minutes. The film properties are as follows:
O95/01~7 6~3~ PCT~S94/06564
- 35 -
Film thickness, Mil 1.5
Impact strength, (in.~lb)
Front 40
Reverse 20
Pencil Hardness F
Gloss
20 deg 67
60 deg 85
MEK double rubs 200
Q W , hours to 50% loss of gloss 2100
Comparative 14B - Powder Coatings from Resin HB and
POWDERLINK 1174 Crosslinker
This comparative shows that HB produces coating
with excellent QUV but poor impact~
Resin HB (376 g), POWDERLINK 1174 (24.0 g), methyl
tolyl sulfonimide (5.0 g), benzoin (4.0 g), MODAFLOW
2000 (6.0 g), 'l'lNUVlN 144 (6.0 g), 'llNuvlN 234 (6.0 g),
and titanium dioxide (160.0 g) were mixed in Vitamix
mixer and compounded in an APV extruder at 125C. The
extrudate was cooled, granulated, and pulverized in a
Bantam mill with liquid nitrogen bled into the grinding
chamber. The powder was classified through a 200 mesh
screen. The powder was electrostatically applied to a 3
in. x 9 in. metal panel and cured in a 350F oven for 20
minutes. The film properties are as follows:
WO95/01~7 PCT~S94/065 -
63~6
- 36 -
Film thickness, Mil 1.8
Impact strength, (in.~lb)
Front 20
Reverse <20
Pencil Hardness H
Gloss
20 deg 73
60 deg 93
MEK double rubs 200
Q W , hours to 50% loss of gloss >1500
Comparative Example 15 - Powder Coatings from Hydroxyl
RUCOTE 107 and ~-Caprolactam
Blocked Isophoronediisocyanate
This comparative shows commercial aromatic resin
produces coating with good impact but poor Q W .
RUCOTE 107 (800 g), Huls 1530 (200.0 g), benzoin
(10.0 g), MODAFLOW III (10.0 g), l'lNUVl~ 144 (14.3 g),
'l'lNUVl~ 234 (14.3 g), and titanium dioxide (400.0 g)
were mixed in a Henschel mixer and compounded in an ZSK
30 extruder. The extruder temperature profile was Feed
zone = 110C, die zone = 125C, and a screw speed of
250 rpm with feeding rate enough to maintain 45% torque.
The extrudate was cooled through a chill roll,
granulated and pulverized using a Bantam mill with
liquid nitrogen bled into the grinding chamber. The
powder was classified through a 200 mesh screen,
electrostatically applied to 3 in. x 9 in. metal panels
and cured in a 350F oven for 20 minutes. The film
properties are as follows:
095/01~7 ~ 663~ 6 PCT~S94/06564
- 37 -
Film thickness, Mil 2.0
- Impact strength, (in.~lb)
Front 160
Reverse 160
Pencil Hardness H
Gloss
20 deg 84
60 deg gs
MEK double rubs 200
Q W, hours to 50~ loss of gloss 240
Examples 16-26
Carboxyl Resin I
To a 3000 ml, 3-neck round bottom flask were added
hydrogenated bisphenol A ~726.5 g, 3.027 moles), 2,2-
dimethyl-1,3-prop~nP~iol t326.4 g, 2.847 moles) and
trimethylolpropane (24.3 g, 0.183 moles) and FASCAT 4100
(1.8 g). The contents were heated to melt at 180C.
1,4-Cyclohexanedicarboxylic acid (951.7 g, 5.526 moles)
was added. The flask was swept with 1.0 scfh nitrogen
while the temperature was raised from 180C to 230C
over a 6-hour period. The batch temperature was
maintained at 230C for 8 hours. The resulting resin
has an acid number of 3 mg KOH~g and an ICI melt
viscosity of 15 poise at 200C. 1,4-Cyclohexane-
dicarboxylic acid (238.2 g) was added at 230C and the
melt was agitated at 230C for 4 hours. The molten
resin was poured into a syrup can where it cooled to a
solid with the following properties:
WO95/01~7 ~ 3~ PCT~S94/06
I.V. 0.174 dl~g
ICI Melt Viscosity at 200C 31 poise
Acid Number 47
Hydroxyl number 5
DSC (2nd cycle)
Tg 60C
Gel permeation chromatography
Mw 6,263
Mn 1,904
Carboxyl Resin II
A 3000 mL, 3-necked, round bottom flask equipped
with a stirrer, a short distillation column, and an
inlet for nitrogen, was charged with dimethyl
cyclohex~nedicarboxylate (1280.8 g, 6.40 mol), 1,4-
butanediol (692.9 g, 7.683 mol, 10% excess), and 100 ppm
of titanium tetraisopropoxide in 2-propanol. The flask
and contents were heated under nitrogen atmosphere to a
temperature of 170C at which point methanol began to
distill rapidly from the flask. After the reaction
mixture was heated with stirring at this temperature for
about 1 hour, the temperature was increased to 200C for
2 hours, raised to 215C for 4 hours, and then to 235C.
After 3 hours at this temperature, a vacuum of 10 mm of
mercury was applied over a period of 12 minutes.
Stirring was continued under 10 mm of mercury at 235C
for about 3 hours to produce a low melt viscosity,
colorless polymer. The resulting polymer was cooled to
200C and 1,4-cyclohexanedicarboxylic acid (228.7 g,
1.33 mol) was added. Heating with stirring was
continued for about 4 hours to produce a resin with an
inherent viscosity of 0.21, a melting point of 134C, an
acid nl~her of 47, and a molecular weight by GPC of
2200.
3S
095/01407 ~ 30~ PCT~S94/06564
- 39 -
Powder coating composition Examples 16 through 22.
Powder coatings from 50~50 Resin I~II and
~-hydroxylalkylamide.
Resin I (186 g), Resin II (186 g), PRIMID XL552
(28.0 g), MODAFLOW 2000 flow aid (6.0 g), benzoin (1.0
g), 'l'lNUVl~ 144 (6.0 g), 'l'lNUVlN- 234 (6.0 g), and
titanium dioxide (200.0 g) were mixed in a Vitamix mixer
and compounded in an APV extruder at 130C. The
extrudate was cooled, granulated, and pulverized in a
Bantam mill with liquid nitrog,en bled into the grinding
chamber. The powder was classified through a 200 mesh
screen. The powder coating described above was mixed
with specified amount of catalyst in a Micromill for
about 1 minute and the gel time of the resulting powder
was determined. The table below demonstrates that gel
time changes with variety and amount of catalyst.
WO 95/01~7 2 ~ ~ ~ 3 ~ PCT~S94/065 -
- 40 -
POWDER # CATALYST WT% CO~ KATION GEL
TIKE
o~ "~
16 None (control) 0 235
17 Zinc Acetate 1.0 147
18 Zinc Acetate 2.0 137
19 Zinc Stearate 1.0 189
Zinc Stearate 3.6 156
21 Titanium 1.0 Ti 128
Isopropoxide
22 Zinc Oxide 1.0 163
Thermosetting powder coating composition Examples
23 through 26. Powder coatings from 50~50 Resin
I~II, ~-hydroxylalkylamide and zinc stearate
coextruded.
Resin I (372 g), Resin II (372 g), PRIMID XL552
(56.0 g), zinc stearate (amount specified in table
below), MODAFLOW 2000 (12.0 g), benzoin (2.0 g), 'l'lNUVlN-
144 (12.0 g), 'l'lNUVl~ 234 (12.0 g), and titanium dioxide
(400.0 g) were mixed in a Henschel mixer and compounded
in an ZSK 30 extruder. The extruder temperature profile
was Feed zone = 110C, die zone = 110C, and a screw
speed of 400 rpm. The extrudate was cooled through a
chill roll, granulated and pulverized using a Bantam
mill with liquid nitrogen bled into the grinding
chamber. The powder was classified through a 200 mesh
~ 095/01407 PCT~S94/06560
2l6~3~
- 41 -
screen. Gel time taken from these powders are listed
below.
5 POWDER # CATA~YST GRAM GEL
TT~
~,cc~. .,c
2:3 None (control) 0 245
24 Zinc Acetate 12.0 188
Zinc Stearate 12.0 197
26 Zinc Stearate 43.0 169
