A water-based coating composition which may be air dried to form durable, fire resistant coatings includes dispersed vinylidene fluoride polymer particles, emulsified liquid epoxy resin and a dissolved emulsifying agent for said epoxy resin which agent is also capable of rapidly curing the epoxy resin upon removal of the water from the composition

Bartoszek, Edward J.

Christofas, Alkis

NASA Technical Reports Server

United States Patent [191 
Bartoszek et al. 
[54] AQUEOUS VINYLIDENE FLUORIDE 
POLYMER COATING COMposFIlON 
[75] Inventors: 
[73] Assignee: 
[21] Appl. No.: 
[22] Filed: 
JMward J. Bprtoszek, Norristow, 
Auds CMstOfas, Levittown, both of 
Pa. 
Pennwalt Corporation, Philadelphia, 
Pa. 
761,191 
Jau. 21,1977 
[51] Int. c1.2 .............................................. CO8L 27/16 
[52] US. Cl. ............ 260/2!).6 NR; 260/29.6 F; 
260/29.6RW 
[58] Field of Search .................. 260/29;6 F, 29.6 NR, 
260/29.6 RW 
[561 References Cited 
U.S. PATENT DOCUMENTS 
3.1 11,426 11/1963 Capron et al. ................... 260/837 R 
3,719,629 3/1973 Martin et al. ................. 260/33.4 EP 
3,857,827 12/1974 Dohaney ......................... 260/29.6 F 
3,962,169 6/1976 Arruda et al. .................. 260/29.6 F 
3,169,120 2/1965 Capron et al. .................. 260/29.6 F 
Primary Examiner-Eugene C. Rzucidlo 
A water-based coating composition which may be air 
dried to form durable, fire resistant coatings includes 
dispersed vinylidene fluoride polymer particles, emulsi- 
fied liquid epoxy resin and a dissolved emulsifying agent 
for said epoxy resin which agent is also capable of rap- 
idly curing the epoxy resin upon removal of the water 
from the composition. 
6 CIPimsr, No Drafigs 
[57l ABsTRAcr 
https://ntrs.nasa.gov/search.jsp?R=20080012243 2019-08-30T03:54:58+00:00Z
2 
4,128,519 
1 
rapidly curing said epoxy resin on removal of water 
AQUEOUS VINYLIDENE FLUORIDE POLYMER from said composition. 
COATING COMPOSITION By the term "vinylidene fluoride polymer" used 
The invention described herein was made in the per- herein is meant not only the high molecular weight 
formance of work under NASA Contract No. NAS 9 - 5 normally solid homopolymer resin of vinylidene fluo- 
14403 and is subject to the provisions of section 305 of ride but also the high molecular weight normally solid 
the National Aeronautics and Space Act of 1958 (72 copolymers of vinylidene fluoride with at least one 
Stat. 435; 42 U.S.C. 2457). comonomer, for example, those selected from the group 
This invention relates to an air-drying latex, topcoat consisting of tetrafluoroethylene, trifluoroethylene, 
formulation including components which are compati- 10 chlorotrifluoroethylene, hexatluoropropene and mix- 
ble and relatively stable in a liquid composition. Resin- tures thereof, said copolymers consisting of at least 
ous vinylidene fluoride polymer is present in the formu- about 50 mole % of polymerized vinylidene fluoride 
lation as the film-former while a liquid epoxy resin and units. A particularly preferred copolymer (terpolymer) 
a water-soluble emulsifier for the epoxy resin, which is is that composed of about 62 weight percent vinylidene 
also a curing agent for the epoxy after removal of the 15 fluoride, about 24 weight percent of tetratluoroethyl- 
water, provide additional beneficial coating properties. ene, and about 14 weight percent of hexafluoropropene. 
Various systems have been devised for laying down m e  vinylidene fluoride polymer is present in the &per- 
films and protective coatings of normally Solid, high sion embodied herein m & p e d  particles having a 
molecular weight vinylidene fluoride polymers to give particle size range of 0.1 micron or smaller up to about 
substrates the protection of polymeric coatings which 20 one micron. 
have good solvent resistance, chemical resistance, Examples of the emulsifiable, liquid epoxy resins 
weather resistance, heat stability, strength, and red-  which are employed for the composition oft& 
ience. However, these known systems have certain invention are set forth in U.S. Pat. No. 3,719,629. The 
disadvantages With regard to Processh3 conditions and patent discloses glycidyl ethers of polyhydric com- 
enVkOnmental Contamination. For example, U.S. pat. 25 pounds which include, for example, glycidyl ethers of 
No. 3,169,120 describes vinylidene fluoride polymer phenols, bisphenols, phenol-aldehyde condensation 
Particles dispersed in an aqueous ComPoSition Contain- products, glycols, polyoxyalkylene glycols and the like, 
ing a major proportion of at least one Water miscible or mixtures of such &idyl ethers. One preferred 
solvent selected from the group Consisting of triethyl- epoxy resin component for this invention is a blend of 
phosphate, dimethyl succinate, diethyl succinate and 30 from about 10-12 parts by weight of a liquid epoxy resin 
tetraethylurea. The disadvantages ofthis system are the of the diglycidyl ether of bisphenol A with from about 
presence Of large amounts Of undesirable, high boiling 1-3 of a liquid epoxy resin of fie diglycidyl ether 
point solvents and the necessity for drying and curing of propylene glycol. 
the polymer film at temperatures in excess of about 175" 
film-forming compositions comprised of vinylidene when the compos~t~on is dried, is advantageously 
latent solvent for the vinylidene fluoride polymer, the type described in U,S. pat. NO. 3,634,372 wherein the 
latent solvent being a volatile organic liquid. The poly- d o a l k Y l  radical is ne acidification of such 
dispersions are dried and cured at temperatures on the sition with aspersed epoxy resin is also disclosed in the 
ne agent for the liquid epoxy C. U.S. Pat. NOS. 3,324,069 and 3,340,222 deal with 35 which also acts as a curing agent for the epoxy resin 
fluoride polymer and a acrylate polymer dispersed in a lected from doa lky la t ed  vinyl interpOlymers of the 
mer films and coatings formed from such non-aqueous 40 copolymers to provide water -able coating compo- 
order of 230" c. with the ever increasing emphasis above mentioned U.S. pat. No. 3,719,629, and the dis- 
being placed on environmental protection, the presence closure of both of the above patents are incorporated 
of large amounts of such volatile and toxic organic herein by reference. me &o&ylated copolymers 
solvents in coating compositions is objectionable be- 45 are further characterized as having pendant 
cause of their air-polluting effects. 
High quality vinylidene fluoride polymer films and 
coatings can be prepared from the non-polluting, sub- 
stantially solvent-free, coating composition of this in- 
vention which coating composition permits drying and 50 
late groups of the formula 
0 
II 
curing of the formed coatings at ambient temperature, 
Le., about 15" to 50" C., although, if desired, the films 
and coatings may be quickly dried and cured at high 
temperature, i.e., up to about 290" C. The dried and where R1 and R2 are independently hydrogen or lower 
cured coatings have superior hardness, abrasion resis- 55 alkyl radicals, and n ranges from about 1.0 to 2.5. The 
tance, adhesion properties, flexibility, resistance to intermediate vinyl carboxylic acid interpolymers are 
chemicals, corrosion protection, weathering properties, prepared, for example, by copolymerking a vinyl car- 
thermal stability, fire resistance, and clarity. boxylic acid, e.g., acrylic, methacrylic, cinnamic, cro- 
Accordingly, this invention comprises an aqueous tonic acid and the like, with one or more copolymeriz- 
coating composition containing €or each 100 parts by 60 able monomers such as vinyl aromatic and aliphatic 
weight of aqueous liquid medium from about 25 to monomers. Preferable vinyl aromatic monomers are 
about 125, preferably about 30 to about 70, parts of styrene, a-methylstyrene, and vinyl toluene. Preferable 
dispersed vinylidene fluoride polymer particles and vinyl aliphatic monomers are methyl, ethyl, isopropyl, 
from about 3 to about 50, preferably about 8 to about 20, butyl and 2-ethylhexyl acrylates or methacrylates. The 
parts of emulsified liquid epoxy resin, and, for each part 65 vinyl interpolymers are preferably prepared with a 
by weight of liquid epoxy resin, from about 0.25 to sufficient amount of vinyl carboxylic acid monomer to 
about 2.5, preferably about 1.0, parts of emulsifying provide at least 3 percent and preferably from about 7.5 
agent for said epoxy resin which agent is capable of to about 12 percent by weight of carboxylic acid (as 
4.128,5 19 
3 
- O H )  and the balance of said interpolymer com- 
posed of the preferred comonomers as indicated above. 
The aminoalkylated interpolymers employed in this 
invention are prepared by an amination reaction in 
which the vinyl carboxylic acid interpolymer in a suit- 
able solvent is reacted with an excess (at least two 
moles) of alkylenimine or N(aminoalky1)-substituted 
alkylenimine. Suitable alkylenimines include ethyleni- 
mine, propylenimine, butylenimine and the like and 
mixtures thereof. Particularly useful N(aminoalky1)- 
substituted alkylenimines are N-(2-aminoethyl)aziriziri- 
dine, N-(3-aminopropyl) aziridine, N-(2-aminopropyl)- 
propylenimine and the like. 
The acidification of the aminoalkylated vinyl poly- 
mer can be accomplished by the simple mixing of the 
polymer and acid in a suitable water miscible solvent or 
solvent blend using, as the acid, one which will form an 
acid salt with the pendant amine moieties. For example, 
suitable acids include hydrochloric acid, phosphoric 
acid, formic and acetic acid. The emulsifhg agent is 2o 
advantageously employed to formulate coating compo- 
sition as a suspension in an inert'liquid carrier, prefera- 
bly water or a mixture of water and a water miscible 
solvent. 
Coating composition additives may be, and prefera- 
bly are, used for the composition of this invention. Dis- 
persed, finely-divided pigments to give the coating or 
film the desired opacity, color or aesthetic appeal are 
used in amounts ranging from about 10 to about 170 3o 
parts by weight of pigment for each 100 parts by weight 
of vinylidene fluoride polymer resin with the provision, 
however, that total solids in the dispersion is not greater 
than about 200 parts per 100 parts by weight of water. 
Representative pigments are rutile titanium dioxide, 35 
various silicates such as talc, mica and clays, barytes, 
carbon black, zinc oxide, zinc sulfide, silicas, iron ox- 
ides, chrome oxides, other metal oxides, powdered met- 
als, glass spheres, and mixtures of the foregoing pig- 
An optional ingredient that may be included in the 
dispersion, in an amount of up to about 20 parts by 
weight per 100 parts by weight of the amount of vinyli- 
dene fluoride polymer resin, is an organic liquid, prefer- 
ably soluble in water in said proportion, which liquid 45 
will act as a coalescing aid in the formation of the poly- 
mer films during the drying step. Representative coal- 
escing agents which may be used in such minor propor- 
tions are butyrolactone, cyclohexanone, tributyl phos- 
phate, methyl or butyl cellosolve acetate, tributox- 50 
yethyl phosphate, carbitol acetate. 
Conventional paint and coating additives, such as 
surfactants, anti-foams, preservatives, protective col- 
loids, thickening agents, pH buffers and others may also 
be included in the composition. The preferred pH for 55 
the composition of this invention is in the range of about 
5 to about 6. 
The coating compositions can be applied to a wide 
variety of substrates including wood, metals, masonry, 
textiles, fabrics, paper, glass, etc. by conventional coat- 60 
ing methods such as spraying, brushing, dipping, cast- 
ing, knife coating, coil coating, reverse roll coating and 
other methods known in the art. The unexpected advan- 
tages of the aqueous dispersion of this invention derive 
from the discovery that durable, hard, and tough coat- 65 
ings are obtained by air-drying at ambient temperatures 
Le., 15' to 50" C. Accordingly, the coatings may be 
applied as high performance maintenance paints in 
25 
ments. 40 
4 
plants and other commercial facilities to protect wood 
and metal surfaces. 
Although adhesion of the film of the polymeric mix- 
ture to substrates is generally more than adequate, in- 
creased adhesion is obtained by first priming the sub- 
strates with a compatible coating layer. For example, 
for wood, a useful primer is a layer of pigmented acrylic 
acid ester polymer as described in U.S. Pat. No. 
3,234,039 and in U.S. Pat. No. 3,037,881. For metal 
coatings, a preferred primer layer is described in U.S. 
Pat. No. 3,111,426, that is an epoxy-based primer. 
Acrylic based primers are also useful for metals, as 
described in U.S. Pat. No. 3,526,532. For coatings on 
glass cloth or other flexible substrates, woven or non- 
woven, known adhesion promoters may be used. In 
particular, glass fiber may be first treated with a silane 
coupling agent as described by I. L. Fan & R. G. Shaw, 
Rubber World, June 1971, page 56. Airdrying of the 
aqueous base polymer coatings on substrates such as 
paper, glass fiber, glass cloth, and non-woven textiles 
may be accomplished at ambient temperatures with 
drying periods of from about 3 to 24 hours. However, 
with forced &-drying at about 50" C. the films will dry 
in 10 to 15 minutes. At 60" C. about 5 to 10 minutes are 
adequate using forced airdrying. In all cases, coatings 
of the polymers mixture are smooth, glossy, and uni- 
form, and the films adhere tenaciously to the substrate. 
Flame resistance and hydrophobicity are imparted by 
the 
The following example is set forth to further demon- 
strate this invention. 
EXAMPLE 
A paint composition was prepared from a three com- 
ponent system as follows: 
PART A 
Aminoethylated hydrochloride salt 
of acrylic copolymer (XD - 7080)'' 
(49% solids in aqueous medium) 
Pigment (fmelydivided T i 0  
Defoamer (DAPRO D F  9119 
Cyclohexanone 
Dionized water. 
PART B -
Liquid epoxy resin of diglycidyl ether 
of bispheuol A (DER 331)** 
Liquid epoxy resin of diglycidyl ether 
of propylene glycol (DER 732)** 
Methyl Cellosolve Acetate 
The above components of Part B are mixed 
together to obtain a homogeneous mixture. 
PART C 
Latex of resinous terpolymer of 62 wt. % 
vinylidene fluoride 24 wt. % tetrafluoro- 
ethyIene and 14 wt. % hexafluoropropene 
(52.4% resin in aqueous medium) 
50 grams@.) 
100 g. 
0.6 g. 
8.0 g. 
15. g. 
18.5 g. 
3.4 g. 
6.1 g. 
192.9 R. 
'Water is added with low shear mixing &I dispersing other components at high 
shear. 
**Products of Dow Chemical Co. 
Part B is added to Part A with gentle stirring. When 
a homogeneous mixture is obtained, Part C is added in 
a similar fashion. The resulting paint has an epoxy resin- 
curing agent content of about 31.5% of total resin solids 
in the composition and is shelf stable for up to six days 
at room temperature. It can be applied by brush, roller, 
or spray to metals such as aluminum, steel, and titanium 
and to wood. The coating dries to the touch in about 
one hour under ordinary ambient temperature and hu- 
midity conditions and is fully cured after 24 hours. The 
cured coatings show hardness, adhesion, abrasion resis- 
4,128,5 19 
5 6 
tance, flexibility, resistance to chemicals, and thermal 
solvent-based polyurethane or polyester coatings. Ex- 
cellent corrosion protection is obtained when the coat- 5 
ing is applied over a conventional primer containing 
rust inhibitors, e.g., acrylic or epoxy primer either latex 
or solvent-based. In addition, the coating has excellent 
85 by accelerated 
stability as good or better than those of commercial 0 
II 
wherein R1 and R2 are independantly selected from the 
POUP comkhi3 Of hydrogen and bwer alkyl radicals 
having 1 to 4 carbon atoms and the average value of n 
ranges from about 1.0 to 2.5, and wherein said ami- 
least 3% by weight pendant-COOH groups. 
tests and is self-extinguishing when applied to non- n o a y l a t d  polymer before aminoaylation contains at 
flammable substrates. 
coating preparatiom employing other vinyli- 2. The composition of claim 1 wherein the vinylidene 
percent vinylidene fluoride, about 24 weight percent 
hexafluoropropene. 
3. The composition of claim 1 wherein the liquid 
The coating compositions of this invention aree unisue 2o epoxy resin consists of a mixture of from about 10 to 
about 12 parts by weight of a liquid epoxy resin of the 
about 3 parts by weight of a liquid epoxy resin of the 
diglycidyl ether of propylene glycol. 
about 10 to about 170 parts by weight of dispersed, 
vinylidene fluoride polymer. 
dene fluoride polymer resins and other liquid epoxy 15 fluoride Polper  is a “polymer Of about 62 weight 
resins or wmbhations thereof are Prepared in a tetrafluoroethylene and about 14 weight percent of 
manner and display excellent modified coating proper- 
ties. 
in that they Bfe easily prepared compatible composi- diglycidyl ether of bisphenol A and from about 1 to 
tions which provide improved coating properties. 
We claim: 
1. aqueous coating composition comprising, for 25 4. The composition of claim 1 which con- from 
fmely-diided pigment for each 1 0  parts by weight of each loo Parts by weight of aqueous liquid 
from about 25 to about 125 parts Of diSperSed polymer 
particles of vinylidene fluoride homopolymer or co- 5. The composition of claim 2 wherein the liquid 
about 12 parts by weight of a liquid epoxy resin of the 
about 3 parts by weight of a liquid epoxy resin of the 
diglycidyl ether of propylene glycol. 
which contains from 
about 10 to about 170 parts by weight of dispersed, 
vinylidene fluoride polymer. 
polymer of at least 50 mol percent vinylidene fluoride 30 epoxy resin 12o~ists Of a mixture of from about lo to 
copolymeked with at least One other copolymerizable diglycidyl ether of bisphenol A and from about 1 to 
monomer and from about 3 to about 50 parts Of emdsi- 
fied liquid epoxy resin, and, for each part by weight of 
liquid epoxy resin, from about 0.25 to about 2.5 parts of 35 
ylated polymer having pendant aminoalkylate groups Of 
the formula 
The composition Of 
an emulsifying agent comprising an acidified fmely-diided pigment for each 100 parts by weight of 
* * * * *  
40 
45 
50 
65 


Aqueous vinylidene fluoride polymer coating composition

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