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MNL17-EB/Jun
...
Burns 1

VINYL RESINS FOR COATINGS

History

Definition

About 1912 Ostromislenski pioneered the industrial investigation of vinyl polymers and made and fractionated
poly(vinyl chloride)
...
W
...
In 1933, Davidson
and McClure described applications of vinyl resins including
their use as swimming pool coatings [1]
...
Carboxyl-modified copolymers were introduced in 1939 and hydroxyl-modified resins
in 1945
...

Organosol and plastisol coatings technology that permitted
the use of very-high-molecular-weight resins were developed
about 1943 [2,3]
...
Functional monomers contribute
specific properties; thus, carboxylic acid-containing monomers provide adhesion, while hydroxyl-containing monomers contribute to reactivity, compatibility with other resins
and polymers, or adhesion to specific surfaces
...

Special techniques have been developed that enable the use
of high-molecular-weight vinyl chloride homopolymers as
dispersions in organic media called plastisols or organosols
that require a heat fusion step to form films or coatings
...
Water-based
vinyl chloride polymers and copolymers include high-molecular-weight polymer latexes that require heat to fuse, and also
aqueous dispersions of low-molecular-weight polymers that
utilize coalescents to form films at room temperature
...
9~ Polymerization is carried out
in autoclaves under moderate to high pressure
...
The polymerization is exothermic, and
reaction temperature regulation is necessary to control the
growth (molecular weight) of the polymer
...
The number average molecular weight (M,) of commercially available
solvent-soluble vinyl chloride homopolymers and copolymers ranges from a low of a few thousand to about 45 000
...


General
Important characteristic features of vinyl resins/coatings
are: (1) relatively high glass transition temperature; (2) excellent resistance to water, alcohols, aliphatic hydrocarbons,
vegetable oils, dilute acids, and alkali; and (3) inertness in
contact with foods (FDA-listed resins only)
...
Suitable heat stabilizers are employed that
allow the processing of vinyl coatings at high temperature,
while proper pigmentation helps to protect vinyl coatings
from attack by UV light
...


Manufacture
Vinyl resins for coatings are made by several processes
...
Some solvent-soluble grades are also made by the emulsion process
...


~Union Carbide Corporation, B o u n d Brook, NJ 08805
...
astm
...
The viscosity of the reaction medium
increases as m o n o m e r is converted to polymer, and the extent
of polymerization can be monitored and controlled via viscometry
...

The particle size of the dried resins produced by this process
ranges from about 75 to about 200 ~m, and the particle shape
is irregular
...
These polymers are
produced by the solution polymerization process
...
Vinyl chloride-vinyl acetate copolymers
...
Carboxyl-modified vinyl chloride-vinyl acetate copolymers
...
Hydroxyl-modified copolymers of two types:
a
...

b
...

4
...

Other suppliers of solvent-soluble vinyl resins and their
product lines are listed in Tables 2 through 5 for Denka
Kagaku, BASF, Wacker Chemie, and Nissan
...
High-molecular-weight water-soluble colloidal polymers are used in small amounts to stabilize the droplets of suspended monomer(s) to control particle size
...
Normally the preparation of
solutions of suspension resins requires that mild heating be
employed to achieve m a x i m u m clarity of solutions at minim u m viscosity
...


Emulsion Polymerization
Like the suspension process, emulsion polymerization is
also carried out in water, but in place of water-soluble polymers, surfactants are normally used to stabilize the smaller
m o n o m e r droplets during polymerization
...
2 to 2
/~m
...


Post-Polymerization Process
Some vinyl-alcohol modified resins are prepared in a twostep process
...
Next, the copolymer resin is dissolved in
a suitable solvent and a catalyst is added to partially hydrolyze the pendant acetoxy groups to yield a vinyl alcohol moiety
...
The resin thus
formed has only secondary hydroxyl groups, which accounts
for its unique solubility/compatibility properties
...


FDA Status
Vinyl copolymer resins are listed by chemical identity in
several U
...
Food and Drug Administration regulations such
as 21CFR 175
...
170, 176
...
1210 as components of coatings on metal and paper substrates for use as
food contact surfaces of articles used in processing, manufacturing packing, producing, heating, packaging, holding, or
transporting food, or as components of closures with sealing
gaskets for food containers
...


Vinyl Resins--Analysis
There are many references to chemical methods for identifying and characterizing vinyl resins [5,6]
...
Spectra of neat vinyl resins can be
found in sources such as atlases, encyclopedia of plastics, or
specific papers dealing with the subject [7-9]
...
ASTM Guide for Testing Poly(Vinyl Chloride) Resins
(D 4368-89) describes methods for homo- and copolymer vinyl resins to determine important characteristics such as
total chlorine content for composition, dilute solution viscometry to assess polymer molecular weight, high and low
shear viscosity measurements to characterize vinyl dispersion resins for plastisols and organosols [10]
...
A spectrum for an ortho-phthalic
alkyd, vinyl chloride-acetate modified vehicle is presented
[11]
...
Each component can then be analyzed by infrared
technique [12]
...

Polymer Composition,
wt%

Inherent
Viscosity,
ASTM
D 1243

Glass
Transition
Temperature
(Tg), ~

Average
Molecular
Wt, M
...
74
0
...
40

79
72
72

44 000
27 000
22 000

1300 i
600
200

0,50
0
...
32

74
72
70

27 000
19 000
15 000

650
100
55

---

67

15 000

--
...
3
2
...
53
0
...
~ ~
1
...
56
0
...
30

70
65
65

33 000
24 000
15 000

930
275
70

Hydroxyl

3
...
15

54

5 5O0

2O

Reactive

UCAR|
Solution
Vinyl

Po/y(vinyl
chloride)

Poly(vinyl
acetate)

VYNS-3
VYHH
VYHD

90
86
86

10
14
14


...


...
0
1
...
0

VERR-40

82

9

9 b'c

Epoxy

1
...

~Maleic acid
...

CSolution--40% resin in MEK/toluene 3 • 2
...

~Hydroxy alkyl acrylate
...

gOn solids
...

J20% resin in MEK
...

Composition, wt%
Grade

Vinyl
Chloride

Vinyl
Acetate

1000A
1000AS
IO00C
1000CS
1000GKT

86
86
86
86
91

14
14
13
13
3

TABLE 3 - - S u s p e n s i o n

vinyls for solution coatings--BASF
...
s

MP-25
MP-35
MP-45
MP-60

75
75
75
75

25
25
25
25

35
35
45
60

a20% resin solutions in toluene
...

T h e r e s i n is n o r m a l l y s e l e c t e d o n t h e b a s i s of its a b i l i t y t o
p r o v i d e a d h e s i o n to t h e s u h s t r a t e , W h i l e , i n m o s t cases,

Carboxylic
Acid

...

1
1

...

6

0
...
4
0
...
4
0
...

T a b l e 6 lists t h e r e l a t i v e a d h e s i o n o f s e v e r a l v i n y l r e s i n s t o
various polymers and substrates
...


Solubility
Variation in the ratio of vinyl chloride to vinyl ester and the
d e g r e e o f p o l y m e r i z a t i o n p r o d u c e a w i d e r a n g e o f v i n y l polymers with different solubility characteristics
...
T h i s r e l a t i o n s h i p i n t e r m s of v i s c o s i t y o f r e s i n s o l u t i o n s is c o m p a r e d i n T a b l e 1
...

Composition,wt%
Vinyl
Acetate
Acid

Vinyl
Chloride

Grade

Acrylic
Ester

Inherent
Viscosity

E 15/45
H 15/45
H 15/50

85
85
85

15
15
15

9
...

9
...
5
0
...
6

H 40/43
H 40/50
H 40/55

60
60
60

40
40
40

9
...


...
46
0
...
7

H 40/60
E 15/45M
H 15/45M

60
84
82

40
15
17

9-
...

9
...
88
0
...
56

E 15/40A
E 20/55A
E 22/48A

85
80
78


...
4
0
...
56

TABLE 5--Suspension vinyls for solution coatings--Nissan
...


...

1


...
Though it was necessary to use more oxygenated solvents, the p e r f o r m a n c e of
c o m p l i a n t coatings stayed the same
...


S o l u t i o n Characteristics
Vinyl solution resins are dissolved by ketones, esters, certain chlorinated solvents, a n d some nitroparaffins
...
Hydrocarbons are
chiefly used as diluents primarily to lower cost
...
Aromatic hydrocarbons, chiefly toluene a n d xylene a n d higher boiling
fractions such as Aromatic 100 or 150, are preferred as they
can be used at high levels, in the range of 50 to 65% of the
solvent b l e n d depending on the resin composition, molecular
weight, a n d desired solids
...

Aliphatic h y d r o c a r b o n s can be used in limited a m o u n t s , up
to a b o u t 30% of the solvent blend
...
The
use of higher boiling aliphatic h y d r o c a r b o n s can cause precipitation of the resin d u r i n g drying
...
However, in
some cases vinyls, usually hydroxyl-modified vinyls, are readily formulated with other resins that are carried in alcohol
...
Careful attention m u s t be paid in vinyl coating formulations that c o n t a i n alcohols to be sure that problems do n o t
develop d u r i n g application a n d drying of the coatings
...

I n response to regulations restricting the type a n d a m o u n t
of solvents used in coatings, such as Los Angeles Rule 66 a n d
later versions, vinyl coatings were reformulated as c o m p l i a n t
systems by reducing the a m o u n t of b r a n c h e d ketones a n d

F r o m the time a vinyl resin is dissolved, the viscosity of
solutions increases with time until a n e q u i l i b r i u m is reached
after which the viscosity r e m a i n s constant
...
The extent of the
viscosity increase is d e p e n d e n t on: (a) resin molecular
weight; (b) solids c o n t e n t of the solution; (c) a n d the strength
of the solvent blend
...
Properly formulated vinyl
resin solutions usually reach a n e q u i l i b r i u m viscosity i n
a b o u t 3 to 5 weeks
...

Vinyl chloride copolymer solutions also exhibit what is
k n o w n as the m e m o r y effect
...
If the solution is then cooled to its original temperature, the viscosity will n o t immediately r e t u r n to its original
value because of the time lag needed for the effect of the
microcrystallinity to redevelop
...
The converse relationship hold w h e n vinyl
solutions are cooled
...
1
...
M o n o m e r i c as well as polymeric plasticizers or compatible polymers with low glass t r a n s i t i o n t e m p e r a t u r e (Tg)
m a y be used to plasticize a vinyl coating
...

Product Type

Substrate

Copolymer
VYHH

Carboxy
Modified
VMCH

Hydroxy
Modified
VAGH
VAGF

WB
Vinyl
AW-875

Steel
Galvanized
Paper (glassine)
Aluminum foil
Polyethylene, treated
Polypropylene, treated
Polysulfone
Acrylic
PVC plastic
ABS plastic
Polycarbonate
Polyphenylene oxide
Polyethylene terephtalate
Impact polystryene
Inked surface

0
0
10
0
0
0
7
10
I0
10
10
4
0
0
0

10
10
10
10
0
0
10
10
10
I0
10
I0
0
0
5

5
5
10
7
0
0
10
10
10
10
10
0
5
0
8-10

0
0
10
10
0
0
10
10
10
10
10
0
0
0
5

Rating: 10 = Pass Scotch Tape Test, no loss of adhesion
...

0 = No adhesion
...


Memory

Effect

180

Compliant with Rule

Non-Regulated

Rule 66 Compliant

MIBK
50 MEK
Toluene or Xylene _ 50
_
Butyl acetate
100% Cyclohexanone
Toluene
Xylene
VM&P naphtha

66/EPA
33/50 Initiative ~

14 MEK
7
46 Acetone
3
9 MIAK
15
12 Butyl acetate
40
7 Cyclohexanone 9
1___22Toluene
6
100 VM&P naphtha 20


...


Ambient
Heated

TABLE 8--Guidelines for viscosity stable solution
...
Most organic a n d inorganic pigments can
be used
...

P r i m e or color pigments which absorb UV r a d i a t i o n m u s t
be used at a level sufficient to protect the vinyl resin
...
For
t i t a n i u m dioxide (TiO2) pigments, a m i n i m u m level of a b o u t
75 p h r is needed to provide resistance to UV light
...
Organic p i g m e n t s that are

I

44
27-34
19-22
15
5
...
Plasticizers are selected to meet the r e q u i r e m e n t s
of the coating that m a y include low-temperature flexibility,
resistance to extraction by solvents, resistance to migration,
to humidity, etc
...
Table 9 presents a listing of plasticizers that are c o m m o n l y used with vinyl resins
...
Ordinarily, a level of 25 p h r (parts per h u n d r e d parts
resin) of plasticizer is considered a b o u t m a x i m u m for use
with coating resins
...
1 - M e m o r y effect,

104 PAINT AND COATING TESTING MANUAL
TABLE 9--Typical plasticizers compatible with solution vinyls
...
Excessive high
loading of pigments can lead to early chalking
...
Plastisols normally require a
minimum amount of about 55 to 60 parts plasticizer per
hundred parts of resin to form a fluid mix
...
The relatively high levels of
plasticizer needed to produce a flowable liquid mix results in
the formation of fused films too soft for use as coatings
...
Additionally, small
amounts of thinner, usually aliphatic hydrocarbon, are used
(up to about 10 wt%) to reduce viscosity and provide better
flow and leveling of the plastisol coating
...

An organosol differs from a plastisol in that much lower
levels of plasticizer are used
...
Because lower levels of plasticizer are used,
films with much greater hardness can be obtained
...
The modifier resin may
contain carboxyl groups to make self-adherent coatings, or it
may be a hydroxyl containing resin to provide functionality to
react with cross-linkers such as amino or phenol/formaldehyde resins to achieve a degree of thermoset properties
...


Tri-2-ethylhexyl phosphate (TOP)
Isodecyl diphenyl phosphate
Polymerics
Adipic acid polyesters
Azelaic acid polyesters

Careful consideration must be given to the selection of the
solvent/diluent mix for organosols to attain the highest solids
coupled with good viscosity stability
...

Plastisols and organosols require a high baking temperature of about 350~ (177~ to fuse the films
...
At fusion, the resin no longer exists as discreet
particles, but rather as a continuous, homogeneous film
...
Undercuring or baking at temperatures lower than that required for fusion will yield films
deficient in tensile strength, elongation, abrasion resistance,
and all other properties
...
Heat stabilizers are usually combinations of
metal salts of organic acids in combination with epoxidized
oils or liquid epoxy resins
...
In such cases, the metallic salts must be
avoided as these will usually cause gellation; typically, mercapto tin or tin ester compounds are used in combination
with an epoxy stabilizer
...

It is, however, more difficult to prepare pigmented
plastisols because there is generally little solvent used to
control viscosity
...


Primers for Plastisols and Organosols
Plastisol coatings need a primer to develop good adhesion
to metal substrates
...
Suitable primers can be formulated from carboxyl-modified vinyl resins and may require the use of thermoset resins
such as amino-formaldehyde or phenolic resins to provide

CHAPTER 15--VINYL RESINS FOR COATINGS
resistance to excessive softening from highly plasticized
plastisol or organosol coatings
...
As beverage cans
evolved from three- to two-piece construction, the vinyl coating also changed from lacquer to hydroxy vinyl/amino-formaldehyde thermosets to meet the need for higher corrosion
resistance
...
The coated coil stock is then formed into the stay-on
tab can ends, an application that requires excellent mechanical properties to withstand the forming steps without cracking
...
Vinyl organosols are further
modified with amino-formaldehyde or phenolic resins to upgrade chemical resistance and permit the use of such coatings for packaging food that will be autoclaved to sterilize the
contents [15]
...
These systems serve as the
primer coat for gasketing compounds made with plastisol or
vinyl resin dry blends
...
This type of resin is used for its
adhesion characteristic, ease of heat sealing, and resistance
to attack by the packaged product
...
This could range from applications such as blister
packaging where the bond needs to be strong enough to cause
substrate failure when the package is opened, to items such
as jellies or cream containers found in restaurants where a
tight but readily peelable bond is required
...

Other applications include decorative coatings for the aluminum foil paper laminates for cigarette packaging, food
wrappers for fast food restaurant items, for butter, marga-

105

rine, soups, and so on
...

Inks
The major markets for vinyl inks are on vinyl surface products such as floor and wall coverings, swimming pool liners,
vinyl upholstery, and garment fabrics
...

Vinyl inks are often reverse printed on a clear vinyl film,
and the printed film is then laminated to substrates such as
wood or metal to make articles having simulated wood finish
...
Inks for
highly plasticized vinyl surfaces are usually formulated with
ester solvents to avoid excessive softening of calendered films
and puckering of the films
...
The inks are applied and dried usually in
web form
...
A
heated die presses the composite to make intimate contact
with the surface, so that when the die is removed, the ink is
firmly bonded to the substrate and the carrier is peeled away
cleanly
...
These systems consisted of a poly(vinyl butyral) wash
primer, vinyl-red lead anticorrosive intermediate coatings
[based on poly(vinyl alcohol)-modified resin needed for adhesion to wash primer], and vinyl copolymer/wood rosin/
cuprous oxide anti-foul top coats
...
S
...

Because of their good water resistance, good weathering
qualities, flexibility, fast dry and ease of application, and
repair, vinyls quickly became established as maintenance finishes
...
Many
specifications have been written that require the use of vinyls
as maintenance paints [16,17]
...
Several coats
were needed to attain coverage sufficient for good corrosion

106

PAINT AND COATING TESTING MANUAL

protection
...


Wood Finishes
Reactive heavy duty vinyl finishes for wood have been developed consisting of a hydroxyl-modified vinyl resin crosslinked with amino/formaldehyde resins
...
Such finishes became
established as the standard for kitchen cabinets because of
their retention of excellent adhesion and water resistance,
particularly when the coated wood becomes wet from high
humidity or water splashing
...


Magnetic Recording Media
Vinyls, especially hydroxy-modified vinyls, have been used
as binders for magnetic iron oxide tapes since the beginning
of the development of tape recording
...
The early binder formulations used alkyd resin as plasticizers, then polyesters; currently, polyurethane resins are used as the plasticizer as the
technology of tapes advanced and placed more stringent requirements on the performance of magnetic tape for audio
and video [20]
...
Powder
coatings are prepared by dry compounding resins, plasticizer, pigments, and additives in ribbon blenders followed by
attrition or dispersion to powder in mixers such as the
Henschel mixer
...
This latter technique produces powders of smaller particle size [21]
...
The metal
parts are heated for fluid bed application so that the powder
will adhere to the part and begin to flow to form a film
...

Cryogenically ground powder coatings are applied by electrostatic powder spray
...
The finer particle size allows the deposition of smoother and thinner films
than is attainable from fluidized bed or powder spray process
...

PVC powder coatings are used to coat products such as
pipe, fencing, and metal furniture
...
In a sense, such
use could be considered analogous to a waterborne version of
an organosol coating
...
These waterbased materials require a high temperature bake to fuse the
resin plasticizer mix into a continuous film
...


Waterborne Vinyl Dispersions
Waterborne vinyl dispersions made from solution-polymerized vinyl copolymers became available in the 1980s
...
Some dispersions are
available with a glycol ether coalescent already present in the
product, and a co-solvent free variety is also available
...
A line of
waterborne vinyl dispersions is shown in Table 10
...


Trends i n V i n y l Coatings
To meet the VOC requirements that are either in place or
proposed for the future, developments in vinyl coatings have
centered on high solids and waterborne systems
...
However, at the low molecular weights needed for high solubility, the performance of
coatings made from such resins was greatly reduced in terms
of chemical resistance and physical properties
...
Though the high solids resins
may be used alone for less demanding applications, they are

TABLE 10--A line of waterborne vinyl resins dispersions
...

bEthylene glycolmonobutylether
...
-

7
...
0

CHAPTER 1 5 - - V I N Y L R E S I N S FOR COATINGS
b e s t used either as a reactive system, with a m i n o - f o r m a l d e h y d e o r isocyanate cross-linker, o r as modifiers for alkyds,
polyester-isocyanate, o r e p o x y - a m i n e coatings to i m p r o v e
initial drying o r set-to-touch rate, or to improve r e c o a t a b i l i t y
[21]
...
The waterborne vinyls are compatible with a wide variety of other waterborne resins with low
VOC content such as acrylics, alkyds, urethanes, and aminoformaldehyde cross-linkers
...
25, No
...

[2] Myers, R
...
S
...
, Treatise on Coatings, Film Forming Compositions, Vol
...

[3] Powell, G
...
, Federation Series on Coatings Technology, Unit 19,
Federation of Societies for Paint Technology, Philadelphia,
April 1972
...
J
...
V
...
H
...

[5] Paint Testing Manual, ASTM STP 500, 13th ed
...
G
...
,
ASTM, Philadelphia, 1972
...
R
...

[7] Infrared Spectra Atlas of Monomers and Polymers, Sadtler Research Labs, Philadelphia, 1980
...
A
...
J
...
14, 1960, p
...


107

[9] An Infrared Spectroscopy Atlas for the Coatings Industry, 4th ed
...
I and II, D
...
Brezinski, Ed
...

[10]ASTM Guide for Testing Poly(Vinyl Chloride) Resins
(D 4368-89), ASTM Book of Standards, Vol
...
03, American
Society for Testing and Materials, Philadelphia, 1993
...
06
...

[12] ASTM Test Method for Analysis of Components in Poly(Vinyl
Chloride) Compounds Using an Infrared Spectrophotometric
Technique [D 2124-70 (1988)], ASTM Book of Standards, Vol
...
01, American Society for Testing and Materials, Philadelphia, 1993
...
J
...
A
...

[14] Hardman, D
...
and Brezinski, J
...
, "Pigmented Vinyl Copolymer Coatings: A Discussion of Factors Influencing Exterior
Durability," Official Digest, Vol
...
476, 1964, pp
...

[15] Good, R
...
, ACS Symposium Series 365, American Chemical
Society, Washington, DC, 1988, pp
...

[16] Corps of Engineers CW-099040, U
...
Department of the Army,
August 1981
...

SSPC-9
...
J
...
, Journal of Protective Coatings and
Linings, Vol
...
9, September 1988
...
P
...
73, No
...

[20] Kreiselmaier, K
...
, "Pigmentation of Magnetic Tapes," Pigment Handbook, Vol
...
C
...
, John Wiley & Sons, New York, 1973
...
, "Vinyl-Modified Epoxy Coatings," Modern Paint
and Coatings, November 1988

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