Eastman™
polyester resin
intermediates
for powder coatings
Eastman
polyester resin
intermediates
™
for powder coatings
Powder coatings continue to grow rapidly as more and more
industrial finishers switch from liquid paint to powder. The
reasons to make the switch are compelling:
• Improved coating performance
• Lower cost in most applications
• Elimination of
– VOC’s (volatile organic compounds)
– HAP’s (hazardous air pollutants)
– Hazardous waste generation/disposal problems.
Over half of the worldwide production of powder coatings
utilizes polyester resins as a significant portion of the binder
system. The broad choices of polyester resins coupled with
the various cross-linker options provide the powder coating
formulator a wide range of coating properties to costeffectively meet most end-use needs.
There are two basic types of thermoset polyester resins for
powders, hydroxyl and carboxyl terminated. Each type utilizes
a different set of cross-linkers to make up the powder coating
binder system. The resin and cross-linker combinations follow:
Polyester resin type
Matching cross-linker type
Hydroxyl terminated
Blocked isocyanates
Tetramethoxymethyl glycoluril
(Powderlink™ 1174)
Carboxyl terminated
Triglycidylisocyanurate (TGIC)
ß-Hydroxylalkylamide (Primid™ XL552)
Epoxy resins
The choice of monomers used in polyester resins has a
significant effect on the appearance, physical properties, and
storage stability of the resulting powder coatings. This
publication describes Eastman Chemical Company’s monomers
as well as the properties they bring to polyester resins and to
powder coatings.
Eastman NPG™ Glycol (Neopentyl Glycol)
Resin properties
CH3
HO—CH2—C—CH2—OH
CH3
IUPAC: 2,2-Dimethyl-1,3-Propanediol
• Eastman NPG™ glycol and purified terephthalic acid (PTA) are
the primary components for most polyester resins for powder
coatings.
• Resins based on NPG glycol and PTA can be made with a
glass transition temperature (Tg) of 52°–68°C (125.6°–
154.4°F) (2nd heating cycle, midpoint by DSC), the most
popular range for powder coatings.
• Resins based on NPG glycol and PTA have low initial color
and good color stability.
Powder coating properties
• Excellent weathering (UV resistance and nonyellowing)
characteristics with cross-linkers such as TGIC,
ß-Hydroxylalkylamide or blocked isocyanate.
• Good powder flow and fluidization characteristics.
• Good balance of hardness and flexibility.
• Good chemical and stain resistance.
PIA (Purified Isophthalic Acid)
Resin properties
O
HO—C—
C—OH
O
IUPAC: 1,3-Benzenedicarboxylic Acid
• PIA is more soluble and therefore more reactive than PTA in
molten glycols and in resins. For this reason, it is often the
monomer of choice for converting hydroxyl resins to
carboxyl resins during the second stage of the resin synthesis.
• PIA/Eastman NPG™ glycol-based resins have a Tg approximately
7°C lower than their PTA/NPG™ glycol counterparts, but the
storage stability of the powders made from these resins is
still adequate.
Powder coating properties
• PIA/Eastman NPG™ glycol-based resins provide coatings with
– Superior weathering (UV resistance) characteristics.
– Less impact resistance and flexibility than other polyester
powders but comparable to that of acrylic powders.
HPHP (Hydroxypivalyl Hydroxypivalate)
CH3
O
CH3
HO—CH2 —C——C—O—CH2 —C—CH2 —OH
CH3
CH3
IUPAC: 3-Hydroxy-2,2-Dimethylpropyl
3-Hydroxy-2,2-Dimethylpropanoate
Resin properties
• HPHP has structural features and reactivity similar to those of Eastman
NPG™ glycol.
• Resin Tg is reduced by approximately 0.2°C for every mole % replacement
of NPG glycol in a PTA/NPG resin.
• HPHP is best suited for carboxyl resins intended for outdoor applications
because carboxyl resins have higher initial Tg than their hydroxyl
equivalent and because of its excellent weathering characteristics.
Powder coating properties
• Improved smoothness and flexibility in TGIC and ß-Hydroxylalkylamide
systems without sacrificing weathering (UV resistance) properties
(Eastman NPG™ glycol and HPHP have similar weathering properties).
• Good chemical and stain resistance.
CHDM (1,4-Cyclohexanedimethanol)
CH2OH
Resin properties
• CHDM has no effect on the Tg as it replaces Eastman NPG™ glycol in
PTA/NPG-based resins.
• CHDM raises the Tg by approximately 0.2°C for every mole replacement
of NPG glycol in PIA/NPG-based resins.
CH2OH
IUPAC: 1,4-Cyclohexanedimethanol
• CHDM’s primary alcohol functionality provides good reactivity during
resin synthesis and low resin color.
Powder coating properties
• CHDM-containing resins provide superior detergent resistance for
appliance and other applications where this property is important.
1,4-CHDA (1,4-Cyclohexanedicarboxylic Acid)
CO2H
Resin properties
• Reduced resin cook time is possible because CHDA is more soluble in
Eastman NPG™ glycol than PTA and therefore reacts faster.
• Tg is reduced by approximately 0.4°C for every mole replacement of
PTA with CHDA in PTA/NPG glycol-based resins.
CO2H
Powder Coating Properties
IUPAC: 1,4-Cyclohexanedicarboxylic Acid
• CHDA-containing resins are particularly well suited for applications where
excellent flexibility is required and where hardness is also important
(i.e., blank and coil coatings, primer surfacers, appliance coatings, etc.).
• Better smoothness (less orange peel) is achieved as CHDA partially
replaces PTA in resins because CHDA is more efficient at reducing melt
viscosity.
Typical Propertiesa
Product
Eastman NPG™ Glycol
Physical
Molecular
Form
Weight
Platelets
104.15
Molten
NPG-90 Glycol
Slurry
104.15
CHDM-D
Solid
144.21
Molten
CHDM-D90
Liquid
144.21
HPHP
Solid
204.26
Nugget
Molten
1,4-CHDA
Powder
172.00
PIA
Powder
166.14
aProperties reported here are typical of average lots. Eastman makes
no representation that the material in any particular shipment will
conform exactly to the values given.
Specific
Assay,
Melting
Boiling
Gravity,
Weight %
Weight %
Point, °C
Point, °C
20°/20°C
Solids
Volatile
99.5
127
210
1.06
100
—
Available Packaging
1,000-kg (2,205-lb) bulk bags
500-kg (1,100-lb) bulk bags
20-kg (44-lb) bags
22.7-kg (50-lb) bags
Tank trucks
89
31b
—
0.94
90
Water
(60°C)
99.5
50
284–288
1.023
Tank trucks
Tank cars
100
—
Cast in 190-kg (419-lb) drums
Tank trucks
90
⫺30–⫹40c
113
0.948
90
Water
205-kg (452-lb) drums
Tank trucks
98.1
46–50
293
1.01
100
—
Cast in 200-kg (441-lb) drums
20-kg (44-lb) bags
Tank trucks
99.5
164–167
—
1.38
100
—
1,000-kg (2,205-lb) bulk bags
500-kg (1,100-lb) bulk bags
20-kg (44-lb) bags
99.8
345–348
—
1.507
100
—
22.7-kg (50-lb) craft bags
25-kg (55-lb) craft bags
500-kg (1,100-lb) bulk bags
1,000-kg (2,205-lb) bulk bags
Bulk railcar
Truckload
bCrystallizes below 31°C (88°F)
cCHDM-D90 is a CHDM-D/water mixture exhibiting multiple melting points across
this range. This complexity makes melting and freezing point determinations difficult.
Eastman suggests CHDM-D90 be stored and handled at temperatures between
⫹30°C and ⫹40°C.
Eastman Chemical Company
Corporate Headquarters
P.O. Box 431
Kingsport, TN 37662-5280 U.S.A.
Telephone:
U.S.A. and Canada, 800-EASTMAN
(800-327-8626)
Other Locations, (1) 423-229-2000
Fax: (1) 423-229-1193
Eastman Chemical Latin America
9155 South Dadeland Blvd.
Suite 1116
Miami, FL 33156 U.S.A.
Telephone: (1) 305-671-2800
Fax: (1) 305-671-2805
Eastman Chemical B.V.
Fascinatio Boulevard 602–614
2909 VA Capelle aan den IJssel
The Netherlands
Telephone: (31) 10 2402 111
Fax: (31) 10 2402 100
Eastman (Shanghai) Chemical
Commercial Company, Ltd. Jingan Branch
1206, CITIC Square
No. 1168 Nanjing Road (W)
Shanghai 200041, P.R. China
Telephone: (86) 21 6120-8700
Fax: (86) 21 5213-5255
Eastman Chemical Japan, Ltd.
AIG Aoyama Building 5F
2-11-16 Minami Aoyama
Minato-ku, Tokyo 107-0062 Japan
Telephone: (81) 3-3475-9510
Fax: (81) 3-3475-9515
Eastman Chemical Asia Pacific Pte. Ltd.
#05-04 Winsland House
3 Killiney Road
Singapore 239519
Telephone: (65) 6831-3100
Fax: (65) 6732-4930
www.eastman.com
Material Safety Data Sheets providing safety precautions,
that should be observed when handling and storing Eastman
products, are available online or by request. You should obtain
and review the available material safety information before
handling any of these products. If any materials mentioned
are not Eastman products, appropriate industrial hygiene
and other safety precautions recommended by their
manufacturers should be observed.
Neither Eastman Chemical Company nor its marketing affiliates
shall be responsible for the use of this information, or of any
product, method or apparatus mentioned, and you must make
your own determination of its suitability and completeness for
your own use, for the protection of the environment and for the
health and safety of your employees and purchasers of your
products. NO WARRANTY IS MADE OF THE MERCHANTABILITY
OR FITNESS OF ANY PRODUCT, AND NOTHING HEREIN WAIVES
ANY OF THE SELLER’S CONDITIONS OF SALE.
Eastman and NPG are trademarks of
Eastman Chemical Company.
All other brands are the property of their respective owners.
© Eastman Chemical Company, 2009.
N-352A 1/09
Printed in U.S.A.