Butvar Properties and Uses

Transcription

Butvar
®
polyvinyl butyral resin
Properties and uses
Contents
Contents
1
1
1
Introduction
Uses
Technical support for specific applications
2
2
6
6
13
15
Properties
Chemistry
Product types
Butvar: the right resin solution
Compatibility
Insolubilizing reactions
17
17
17
17
17
18
Applications
Wire enamels
Surface coatings
Wash primers
Military specification wash primers
Nonspecification wash primers: B-1030 with Butvar
Single-package wash primer: B-1011 with Butvar
Chromate-free wash primers with Butvar
Metal coatings
18
19
20
21
21
21
22
22
22
22
23
23
23
24
24
24
25
26
26
27
Wood finishes
Protective wash coats and sealers
Knot sealers
Adhesives
Structural adhesives
Phenolic resins
Expoxies and other thermosetting resins
High-strength bonding procedure
Performance characteristics
Adhesive strengths
Hot melt adhesives
Textile coatings
Advantages as textile coating
Ceramic binder applications
Tape casting
Thick films
Toners and printing inks
28
28
28
28
Storage and handling
Storage
Toxicity and FDA status
Quality control
29
Material sources
Introduction
Polyvinyl butyral resins are employed in
a wide array of industrial and commercial
applications. These unique resins offer
impressive performance, as well as
outstanding versatility.
Butvar® polyvinyl butyral resins have a combination of
properties that make them a key ingredient in a variety of
successful formulations. Some of these properties for which
Butvar is widely used are outstanding binding efficiency,
optical clarity, adhesion to a large number of surfaces, and
toughness combined with flexibility.
Solutia offers six grades of Butvar resins that cover a broad
range of chemical and physical properties. These resins
are generally well suited either as a major ingredient of
a formulation or in smaller quantities to enhance the
properties of other resins.
Uses
Some of the applications in which Butvar is a vital ingredient include:
• Ceramic binders
• Inks/dry toners
• Wood coatings
• Wash primers
• Composite fiber binders
• Structural adhesives
• Other diverse uses
Butvar resin was pioneered by Monsanto in the 1930s as the key ingredient for automotive safety glass interlayers. It still enjoys widespread use in automotive and
architectural applications for laminated safety glass.
Technical support for
specific applications
Solutia’s technical support and research staff for Butvar
resins can assist in your specific application needs. The
Customer Service Center at 1-800-964-5224 stands ready to receive your orders for samples and technical literature,
as well as purchase orders for shipment of Butvar resin.
1
Properties
Chemistry
The conditions of the acetal reaction and the concentration
of the particular aldehyde and polyvinyl alcohol used are
closely controlled to form polymers containing predetermined
proportions of hydroxyl, acetate, and acetal groups. The final
product may be represented by the following stylized structure.
Acetals, such as polyvinyl butyral, are formed by the
well-known reaction between aldehydes and alcohols. The
addition of one molecule of an alcohol to one molecule of
an aldehyde produces a hemiacetal. Hemiacetals are rarely
isolated because of their inherent instability but, rather, are
further reacted with another molecule of alcohol to form a
stable acetal.
The proportions of A, B, and C are controlled, and they are
randomly distributed along the molecule.
Polyvinyl acetals are prepared from aldehydes and polyvinyl
alcohols. Polyvinyl alcohols are high molecular weight resins
containing various percentages of hydroxyl and acetate
groups produced by hydrolysis of polyvinyl acetate.
H
R — C + R1 — OH
O
H
H
R — C — OR + R1 — OH
OH
Alcohol
Aldehyde
Alcohol
Hemiacetal
CH2
H
H
CH2 — C
C
O
O
Acetal
H
H
CH2 — C
CH2 — C
O
OH
C
H
C
C3H7
PV Butyral
O
CH3
A
2
R — C (— OR1)2 + H2O
B
PV Alcohol
C
PV Acetate
Table 1. Physical properties of Butvar® resins (white, free-flowing powder)
Property
Units
ASTM method
B-72
B-74
B-76
B-79
B-90
B-98
Volatiles,a max
%
—
3.5
3.0
5.0
5.0
5.0
5.0
Molecular wt (weight average in thousands)
—
(1)
170–250
120–150
90–120
50–80
70–100
40–70
Solution viscosity 15% by weight
cp
(2)
7,000–14,000
3,000–7,000
500–1,000
100–400
600–1,200
200–400
Solution viscosity 10% by weight
cp
(2)
1,600–2,500
800–1,300
200–450
75–200
200–400
75–200
Ostwalda solution viscosity
cp
(3)
170–260
37.0–47.0
18.0–28.0
9.0–16.0
13.0–17.0
6.0–9.0
Specific gravity 23˚/23˚ (±0.002)
—
D792–50
1.100
1.100
1.083
1.083
1.100
1.100
Burning rate
ipm
D635–56T
1.0
1.0
1.0
1.0
0.9
0.9
Refractive index (±0.0005)
—
D542–50
1,490
1.490
1.485
1.485
1.490
1.490
Water absorption
(24 hours)
%
D570–59aT
0.5
0.5
0.3
0.3
0.5
0.5
Hydroxyla content expressed as % polyvinyl alcohol
—
—
17.5–20.0
17.5–20.0
11.5–13.5
11.0–13.5
18.5–20.5
18.0–20.0
Acetate content expressed as % polyvinyl acetate
—
—
0–2.5
0–2.5
0–2.5
0–2.5
0–2.5
0–2.5
Butyral content expressed as % polyvinyl
butyral, approx.
—
—
80
80
88
88
80
80
Specification properties
a
All properties were determined by ASTM methods except the following:
• Molecular weight was determined via size exclusion chromatography
with low-angle laser light scattering (SEC/LALLS) method of Cotts
and Ouano in tetra-hydrofuran.b
• Solution viscosity was determined in 15% by weight solutions in
60:40 toluene: ethanol at 25˚C, using a Brookfield Viscometer. Also
in 10% solution in 95% ethanol @ 25˚C using an Ostwald-CannonFenske Viscometer.
• Ostwald solution viscosity for each product type measured with an
Ostwald.Cannon-Fenske Viscometer. The solvents and solids levels
used are as follows:
Product
Percent
solids
Solvent
Temperature
(C˚)
B-72
7.5
Anhydrous
methanol
20
B-76, B-79
5.0
SD 29 ethyl
alcohol
25
B-74, B-90, B-98
6.0
Anhydrous
methanol
20
P. Dublin, ed.,
ed.,Microdomains
MicrodomainsInInPolymer
PolymerSolutions
Solutions(New
(NewYork:
York:Plenum
PlenumPress,
Press,
1985),
1985),
pp. 101-119.
pp. 101-119.
b
b
3
Table 2. Chemical properties of Butvar® resins
Property
Units
ASTM method
B-72
B-74
B-76
B-79
B-90
B-98
Weak acids
—
D543-56T
E
E
E
E
E
E
Strong acids
—
D543-56T
E
E
E
E
E
E
Weak bases
—
D543-56T
E
E
E
E
E
E
Strong bases
—
D543-56T
E
E
E
E
E
E
Alcohols
—
D543-56T
P
P
P
P
P
P
Chlorinated
—
D543-56T
G
G
F
F
G
G
Aliphatic
—
D543-56T
E
E
F
F
E
E
Aromatic
—
D543-56T
F
F
P
P
F
F
Esters
—
D543-56T
F
F
P
P
F
F
Ketones
—
D543-56T
F
F
P
P
F
F
Resistance to:
Organic solvents:
Key: E – excellent
G – good
F – fair
P – poor
Table 3. Mechanical properties of Butvar resins
Property
Units
ASTM method
B-72
B-74
B-76
B-79
B-90
B-98
Yield
103 psi
D638-58T
6.8–7.8
6.8–7.8
5.8–6.8
5.8–6.8
6.3–7.3
6.3–7.3
Break
3
10 psi
D638-58T
7.0–8.0
7.0–8.0
4.6–5.6
4.6–5.6
5.7–6.7
5.6–6.6
Yield
%
D638-58T
8
8
8
8
8
8
Break
Tensile strength:
Elongation:
%
D638-58T
70
75
110
110
100
110
Modulus of elasticity
(apparent)
105 psi
D638-58T
3.3–3.4
3.3–3.4
2.8–2.9
2.8–2.9
3.0–3.1
3.1–3.2
Flexural strength, yield
103 psi
D790-59T
12–13
12–13
10.5–11.5
10.5–11.5
11–12
11–12
M
—
D785-51
115
115
100
100
115
110
E
—
D785-51
20
20
5
5
20
20
ft.lb./in.
D256-56
1.1
1.1
0.8
0.8
0.9
80
Hardness, Rockwell:
Impact strength Izod,
notched ½" x ½"
*Specification properties
4
Table 4. Thermal properties of Butvar® resins
Property
Units
ASTM method
B-72
B-74
B-76
B-79
B-90
B-98
Flow temperature,
1,000 psi
ºC
D569-59
145–155
135–145
110–115
110–115
125–130
105–110
Glass transition temperature (Tg)
ºC
(4)
72–78
72–78
62–72
62–72
72–78
72–78
In nitrogen
%
(5)
<3.0
<3.0
<2.0
<2.0
<3.0
<3.0
In air
%
(5)
<1.0
<1.0
<0.75
<0.75
<0.75
<0.75
Heat distortion temperature
ºC
D648-56
56–60
56–60
50–54
50–54
52–56
45–55
Heat sealing temperature
ºF
(6)
220
220
200
200
205
200
Ash content at 550ºC:
• Glass transition temperature (Tg) was determined by Differential
Scanning Calorimeter (DSC) over a range of 30˚C to 100˚C on dried
granular resin.
• Ash content of the Thermal Gravimetric Analysis (TGA) was
determined as a weight loss versus temperature profile conducted at a heating rate of 10˚C/min. • Heat-sealing temperature was determined on a 1-mil dried film on paper cast from a 10% solution in 60:40 toluene:ethanol. A dwell time of 1.5 seconds at a 60 psi line pressure was used on the heat sealer. Table 5. Electrical properties of Butvar® resins
Property
Units
ASTM method
B-72
B-74
B-76
B-79
B-90
B-98
50 cps
—
D150-59T
3.2
3.2
2.7
2.7
3.2
3.3
10 cps
—
D150-59T
3.0
3.0
2.6
2.6
3.0
3.0
106 cps
—
D150-59T
2.8
2.8
2.6
2.6
2.8
2.8
10 cps
—
D150-59T
2.7
2.7
2.5
2.5
2.7
2.8
50 cps
—
D150-59T
0.0064
0.0064
0.0050
0.0050
0.0066
0.0064
10 cps
—
D150-59T
0.0062
0.0062
0.0039
0.0039
0.0059
0.0061
106 cps
—
D150-59T
0.027
0.027
0.013
0.013
0.022
0.023
10 cps
—
D150-59T
0.031
0.031
0.015
0.015
0.023
<0.24
Short time
v/mil
D149-59
420
420
480
480
450
400
Step-by-step
v/mil
D149-59
400
400
390
390
370
380
Dielectric constant:
3
7
Dissipation factor:
3
7
Dielectric strength
(l" thickness):
*Specification properties
5
Product types
Butvar: the right resin solutions
The properties of the various types of Butvar® resins are
described in Tables 1 through 5. The resins are offered in a
variety of molecular weight ranges and viscosities. B-76 and
B-79 have a lower hydroxyl content than the other Butvar
resins. This permits broader solubility characteristics.
Butvar brand resins generally are soluble in alcohols, glycol
ethers, and certain mixtures of polar and nonpolar solvents.
A representative list of Butvar solvents can be found in Table 6. In general, Butvar B-98 resin will show the same
general compatibility characteristics as B-90 and, therefore,
should prove advantageous where physical and chemical
properties of B-90 are desired but lower solution viscosities
are necessary. The same is true for Butvar B-79 in relation to B-76.
As a general rule, the substitution of butyral groups for
acetate groups results in a more hydrophobic polymer with
a higher heat distortion temperature. At the same time, the
polymer’s toughness and adhesion to various substrates is
considerably increased. The outstanding adhesion of the
polyvinyl butyral resins is a result of their terpolymer
constitution. Because each molecule presents the choice of
three different functional groups to a surface, the probability
of adhesion to a wide variety of substrates is increased
substantially.
Although polyvinyl butyral resins normally are thermoplastic
and soluble in a range of solvents, they may be crosslinked
through heating and with a trace of mineral acid. Crosslinking
is generally caused by transacetalization but also may
involve more complex mechanisms, such as a reaction
between acetate or hydroxyl groups on adjacent chains.
As a practical matter, crosslinking of the polyvinyl butyrals is carried out by reaction with various thermosetting resins,
such as phenolics, epoxies, ureas, diisocyanates and
melamines. The availability of the functional hydroxyl groups
in Butvar resins for condensations of this kind is an
important consideration in many applications. Incorporation
of even a small amount of Butvar resin into thermosetting
compositions will markedly improve toughness, flexibility,
and adhesion of the cured coating.
Polyvinyl butyral films are characterized by high resistance
to aliphatic hydrocarbons, mineral, animal, and vegetable oils (with the exception of castor and blown oils). They
withstand strong alkalis but are subject to some attack by
strong acids. However, when employed as components of
cured coatings, their stability to acids, as well as solvents
and other chemicals, is improved greatly. Butvar will
withstand heating up to 200˚F for prolonged periods with
little discoloration.
6
When an alcohol is the only solvent, the viscosity of a
Butvar solution increases as the molecular weight of the
alcohol increases. Blends of alcohols with aromatic solvents
provide the best starting point for the development of
solvent systems. Where alcohols, such as ethyl or isopropyl,
are employed either alone or in a mixture with other solvents,
use the 95% grades. The presence of water gives lower solution
viscosities than solutions utilizing anhydrous alcohols.
Butvar solutions show very marked viscosity increases as resin
solids increase. This effect is shown in Graphs 3 through 10.
The lower hydroxyl content of Butvar B-76 and B-79 permits
solubility in a wider variety of organic solvents as compared
to the other grades of Butvar. One notable exception,
however, is the insolubility of Butvar B-76 and B-79 in
methanol. All other types of Butvar contain sufficient
hydroxyl groups to allow for solubility in alcohol and in
hydroxyl-containing solvents. The presence of both butyral
and hydroxyl groups permits solution in mixtures of alcohol
and aromatics.
Viscosities of Butvar resin solutions containing mixed solvents
depend on the ratio of alcohol to aromatic. Viscosity curves
for Butvar B-76, B-90, and B-98 in Graph 2 show minimum
points in the general vicinity of 50% alcohol:50% aromatic.
Table 6. Solubility of Butvar® resins
Butvara
B-72, B-74
Butvarb
B-76, B-79
Butvarb
B-90, B-98
S
S
S
Acetone
I
S
SW
2-Butoxyethanol
S
S
S
n-butyl acetate
I
S
PS
n-butyl alcohol
S
S
S
n-butyl propionate
I
S
I
Cyclohexanone
S
S
S
Diacetone alcohol
PS
S
S
Diisobutyl ketone
I
SW
I
PS
S
PSc
N,N-dimethylacetamide
S
S
S
N,N-dimethylformamide
S
S
S
Dimethylsulfoxide
S
S
S
Ethyl acetate, 85%
S
S
S
Ethyl acetate, 99% I
S
PS
Ethyl alcohol, 95% or anhydrous
S
S
S
Ethylene dichloride
SW
S
SW
Isophorone
PS
S
S
Isopropyl acetate
I
S
I
Isopropyl alcohol, 95% or anhydrous
S
S
S
Methyl acetate
I
S
PS
Solvent
Acetic acid (glacial)
Dimethyl esters
Methyl alcohol
c
S
SW
S
Methyl amyl ketone
SW
S
PS
Methyl ethyl ketone
PS
S
PSc
Methyl isoamyl ketone
I
S
SW
Methyl isobutyl ketone
I
S
I
SW
S
SWc
Methylene chloride
PS
S
S
N-methyl-2-pyrrolidone
S
S
S
Naphtha (light solvent)
I
SW
I
Propyl propionate
I
S
I
Methyl propyl ketone
c
Propylene dichloride
S
S
S
Tetrachloroethylene
SW
SW
SW
S
S
S
SW
SW
SW
S
S
S
SW
S
SW
I
PS
SW
Tetrahydrofuran
Toluene
Toluene: ethyl alcohol, 95% (60:40 by weight)
1,1,1-trichloroethane
Xylene 5% solids solution agitated for 24 hours at room temperature
10% solids solution agitated for 24 hours at room temperature
c
Clear solution at 50º–80ºC
a
b
Key: S – soluble
PS – partially soluble
I – insoluble
SW – swells
7
A common solvent for all of the Butvar® resins is a
combination of 60 parts toluene and 40 parts ethanol (95%) by weight. The viscosities of all the Butvar resins
in this solvent blend are shown in Graphs 2 and 3. The
viscosities of Butvar resins in alcohols are shown in Graphs 4 through 8. Graphs 9 and 10 present the viscosities of
Butvar resins in 2-Butoxyethanol.
Aliphatic hydrocarbons can be tolerated in only very small
proportions. Aromatic hydrocarbons, alcohols, esters, ketones,
and halocarbons, when not active solvents, are generally
satisfactory as diluents or latent solvents. Solvent blends
are more likely to be successful when their mean solubility
parameter and hydrogen bonding fall within the ranges
shown in Graph 1 and Table 8.
For compositions of Butvar, methyl alcohol will tend to give
the lowest viscosity and, therefore, will permit the use of
higher solids when used as a component of a solvent blend.
When much more than 10% to 15% alcohol is used in a
formulation for spray application, blushing may result.
The Butvar resins can be dissolved quite rapidly using
conventional techniques. To ensure thorough and uniform
wetting of all particles, it is important to add the resin
slowly to the solvent system with adequate stirring. With
some mixed solvents, it may be desirable to slurry the resin
in the hydrocarbon or other nonsolvent component and add
the more active solvent components to the slurry under
adequate agitation.
The solvent blends in Table 7 are suggested for all Butvar
grades. They are useful as starting points in the development
of solvent blends for the other types.
Selection of a suitable solvent system involves a number
of factors. End-use and application technique used will
necessitate consideration of solution viscosity, cobweb
formation, blushing, evaporation, solvent release, and toxicity
characteristics. In most cases, the choice of components of
solvent blend will involve compromises in at least some of
these factors so that a desired combination of properties
may be obtained.
Table 7. Suggested solvent blends for Butvar® resins
Diacetone alcohol
A
B
C
D
22.5%
20.0%
15.0%
—
n-butyl alcohol
22.5
20.0
15.0
—
Ethyl alcohol, 95%
10.0
20.0
20.0
55.0%
Xylene
45.0
40.0
30.0
—
Toluene
—
—
20.0
45.0
Total
100.0
100.0
100.0
100.0
Relative viscosity
High
Medium
Low
Low
Relative evaporation rate
Slow
Medium
Medium
Very fast
Application technique
Spray
Dip, roll
Dip, roll
Brush
Drying technique
Bake
Bake
Bake
Air dry
8
D
Graph 1. Hansen solubility parameters of Butvar® resinsa
H
30
30
Polyvinyl butyral
Hansen solubility
parameters
Dispersive
δD (MPaa)
Polar
δP (MPaa)
H-bonding
δH (MPaa)
Sphere radius
(MPaa)
● B-90 and B-98
21.72
7.85
14.55
15.0
● B-72 and B-74
21.19
8.70
14.02
13.7
● B-76 and B-79
17.72
7.18
12.62
9.7
24
24
18
18
12
12
6
6
HSPiP Software, Version 4.0.08, 2013.
a
6
In general, solvents or solvent mixtures having δD, δP, and δH coordinates within a polymer
sphere, RED ≤1, are solvents; those outside a sphere are nonsolvents. Relative Energy Difference (RED) = [4(δD2-δD1)2+(δP2-δP1)2+(δH2-δH1)2]½/Sphere Radius
12
18
24
24
30
21
18
P
15
27
Table 8. Hansen solubility parameters for common solvents and solvent mixturesa
Solvent
Solvent ratio (wt%)
Dispersive
δD (MPaa)
Polar
δP (MPaa)
H-bonding
δH (MPaa)
Acetone
100
15.5
10.4
7.0
2-butoxy ethanol
100
16.0
5.1
12.3
n-butyl acetate
100
15.8
3.7
6.3
Diisobutyl ketone
100
16.0
3.7
4.1
N,N-dimethylacetamide
N,N-dimethylacetamide/xylene
Dimethyl sulfoxide
Dioxane
100
16.8
11.5
9.4
60/40
17.2
7.2
7.3
100
18.4
16.4
10.2
100
17.5
1.8
9.0
50/50
17.1
3.9
8.5
Ethanol
100
15.8
8.8
19.4
Ethanol/water
95/5
15.8
8.2
20.5
Ethyl acetate/ethyl alcohol
99/1
15.8
5.3
7.3
Ethylene dichloride
100
18.0
7.4
4.1
Ethylene glycol
100
17.0
11.0
26.0
Isopropanol
100
15.8
6.1
16.4
Isopropanol/water
98/2
15.8
6.3
16.8
Methanol
100
14.7
12.3
22.3
Methyl amyl ketone
100
16.2
5.7
4.1
Methylene dichloride
100
17.0
7.3
7.1
100
15.3
6.1
4.1
Propylene glycol monomethyl ether
100
15.6
6.3
11.6
Propylene glycol monomethyl ether acetate
100
15.6
5.6
9.8
Tetrahydrofuran
100
16.8
5.7
8.0
Toluene
100
18.0
1.4
2.0
Toluene/ethanol
50/50
16.9
5.2
11.0
Trichloroethane
100
16.8
4.3
2.0
Xylene
100
17.8
1.0
3.1
50/50
17.2
6.1
6.6
Dioxane/tetrahydrofuran
Xylene/N,N-dimethylacetamide
Charles M. Hansen, Hansen Solubility Parameters: A User’s Handbook, 2nd Edition, CRC Press (2007). a
9
Graph 2. Viscosities of Butvar in toluene-ethanol (95%) (15% solids)
1,800
Graph 3. Viscosities of Butvar in 60/40
toluene-ethanol (95%) (by weight)
100,000
— B-76
1,600
— B-72
— B-90
— B-76
— B-98
— B-79
— B-90
10,000
— B-98
1,400
1,000
1,200
1,000
Brookfield Viscosity at 25ºC-cp
100
800
600
400
1
0
5
10
200
Percent total solids
0
0
20
40
60
80
100
80
60
40
20
Toluene
Ethanol
Solvent composition by weight
10
10
15
20
25
30
Graph 4. Viscosities of Butvar in methanol
100,000
Graph 5. Butvar in ethanol (95%)
100,000
— B-72
— B-72
— B-74
— B-90
— B-98
10,000
10,000
1,000
100
10
0
5
10
15
10
1
0
5
10
15
20
25
30
Graph 6. Butvar in ethanol (95%)
100,000
— B-76
— B-79
— B-90
— B-98
1,000
100
1,000
100
10
0
5
10
15
11
Graph 7. Butvar in n-Butanol
Graph 9. Butvar in 2-Butoxyethanol
100,000
10,000
— B-72
— B-76
— B-79
— B-74
— B-98
10,000
1,000
1,000
100
10
0
5
10
15
100
10
0
5
10
15
Graph 8. Butvar in n-Butanol
Graph 10. Butvar in 2-Butoxyethanol
10,000
100,000
— B-76
— B-72
— B-74
— B-79
— B-90
— B-90
10,000
— B-98
1,000
100
10
0
5
12
10
15
1,000
100
10
0
5
10
15
Compatibility
The compatibility of Butvar® polyvinyl butyral resins with
plasticizers, modifiers, and other various resins is well
established. Butvar readily lends itself to compounding with
other additives to enhance its physical and chemical properties.
Plasticizers are often used to impart improved flexibility over a broader temperature range. See Table 9.
Table 9. Plasticizers for Butvar® resin
Known Butvar:plasticizer
compatibility level
Type
Name or trademark
Hexanoate
Eastman TEG-EH (triethylene glycol di-2-ethylhexanoate)
1:1
Adipate
Santicizer® 97 (dialkyl adipate)
4:1
Santicizer 367 (dihexyl adipate)
3:1
Dioctyl adipate (DOA)
4:1
Blown linseed oil
Linseed oil
—
Citrate
Tributyl citrate
—
Phosphate
Santicizer 141 (2-ethylhexyl diphenyl phosphate)
1:1
Santicizer 148 (isodecyl diphenyl phosphate)
1:1
Santicizer 154 (Tert-butylphenyl diphenyl phosphate)
1:1
Santicizer 143 (triaryl phosphate ester blend)
1:1
Tricresyl phosphate (TCP)
1:1
Triphenyl phosphate (TPP)
2:1
Santicizer 261 (alkyl benzyl phthalate)
2:1
Santicizer 278 (alkyl benzyl phthalate)
4:3
Santicizer 160 (butyl benzyl phthalate)
1:1
Dibutyl phthalate (DBP)
1:1
Dialkyl phthalate
4:1
Dioctyl phthalate (DOP)
4:1
PE glycol ether
Pycal 94
—
Polyester
Paraplex™ RGA-8
—
Process castor oil
#15, #30, #40
2:1
Raw castor oil
#1 Castor
1:1
Ricinoleate
Flexricin™ P3 (butyl ricinoleate)
2:1
Rosin derivatives
Hercolyn
—
Sebacate
Dibutyl sebacate
—
Sulfonamide
Ketjenflex 8 (n-ethyl toluenesulfonamide)
1:1
Ketjenflex 9S (toluenesulfonamide)
2:1
Phthalate
™
™
™
™
The values given in this table are a guide to the compatibility limits of the plasticizers in the various resins shown. (If no value is given, the limit is unknown.) The highest concentration tested was 100 phr. Where the value is given as 1:1, some plasticizer/
resin combinations may have even greater compatibility. However, since the values given apply to a resin type, the compatibility
with a particular commercial grade should be checked when evaluating a specific compound, particularly if the plasticizer content
of the formulation is to be near the ceiling value indicated.
13
Crosslinkers such as Santolink® phenolic and Resimene® amino
resins are used to impart greater toughness and thermal resistance.
Table 10 depicts the compatibility of Butvar® polyvinyl butyral
resins with other modifiers and resins.
Table 10. Compatibility of Butvar with various resinsa
Solvent
Acrylate
—
Alkyd
Cellulose
Butvar
B-76, B-79
Butvar B-72, B-74,
B-90, B-98
I
I
™
Beckosol 11-035
P
P
Duraplex™ 11-804
P
P
Cellulose acetate
I
I
Cellulose acetate butyrate
P
P
Ethyl cellulose
P
P
™
Nitrocellulose, RS
C
C
Nitrocellulose, SS™
C
C
Chlorinated rubber

—
I
I
Coumarone-indene
—
I
I
Epoxy
Epi-Rez 540-C
C
C
Epon 1001F, 1007F
C
C
Araldite 6069
C
C
Fossil
Damar
C
C
Isocyanate
Desmodur™ AP Stabil
C
C
Melamine formaldehyde
Resimene® 717 and 881
P
P
™
™
™
Phenolic
Resimene® 730 and 741
P
P
OxyChem™ 02620, 92600, 29107
C
C
Durite™ P-97
C
C
Methylon 75-108
C
C
Santolink® EP 560 (butyletherified)
C
C
SP-1044 resin
C
C
Pentalyn™ H
P
P
Staybelite ester 10
C
P
™
Rosin derivatives
™
Vinsol
C
C
Shellac
—
C
C
Silicone
DC 840
C
P
DCZ 6018
C
P
Sulfonamid
Ketjenflex MH
P
P
Urea formaldehyde
Resimene® 918
P
P
Vinyl chloride copolymer
VAGH, VAGD
P
I
™
™
Refers to film compatibility provided mutual solvents are used.
a
Key: C – compatible in all proportions
P – partially compatible
I – incompatible
14
Insolubilizing reactions
Reaction with phenolics
Many applications for the vinyl acetal resins involve curing
with a thermosetting resin to obtain the balance of properties
desired. The free hydroxyl groups in vinyl acetal resins present
a point of chemical reactivity through which the resins may
be insolubilized. In general, any chemical reagent or resinous
material which reacts with secondary alcohols will react with
the polyvinyl butyral to inhibit solubility.
BUTVAR
PHENOLIC
OH
OH
OH
HOH 2 C
(R)
C H 2 OH
OH
CH 3
The properties of coatings vary greatly with the type and
amount of crosslinking agent used.
H
+
CH3
BUTVAR
BUTVAR
O
OH
OH
H2 C
(R)
CH 2
O
CH 3
CH3
BUTVAR
Reaction with epoxies (anhydride cure)
CH 3
CH3
CH 2
O
CH
CH2
O
C
CH 3
O
CH 2
Typical epoxy resin
CH
OH
CH 2
O
C
X
O
BUTVAR
OH
O
O
C
O
C
O
C
O
O
C
CH
O
CH 2
OH
O
CH
CH 2
O
CH 3
BUTVAR
CH 2 CH
CH 2
EPOXY
15
Reaction with dialdehydes
Reaction with isocyanates
BUTVAR
BUTVAR
BUTVAR
OH
CH
CH2
CH
CH
O
O
O
R
CH
H+
HC
NCO
HC
OH
CH
CH 2
O
CH
O
OH
CH
O
OH
CH 2
BUTVAR
CH
Reaction with melamines
BUTVAR
OH
N
NH
C
N
C
N
NH
N
(R)
HN
NH 2
C
C
N
MELAMINE
RESIN
C
NH
N
C
HO
NH 2
H+
CH 2 OH
BUTVAR
BUTVAR
O
H 2C
16
N
NH
C
N
C
C
N
N
NH
(R)
HN
DIISOCYANATE
O
NH
R
Tertiary amine
NH
C
O
BUTVAR
CH
BUTVAR
HOH 2 C
O
CH
NCO
OH
OH
CH 2
C
C
N
N
C
C
NH 2
NH 2
NH
CH 2
O
BUTVAR
O
Applications
Wire enamels
Butvar® resins may be used to overcoat magnet wire so that
coils made from that wire can be cemented with heat or by
solvent activation.
Coiled or shaped magnet wire with a polyvinyl butyral
overcoat is tough and flexible. The presence of hydroxyl
groups in the polyvinyl butyral molecule permits the
polyvinyl butyral not only to crosslink with itself but also to crosscure with phenolic or isocyanate resin.
The overall balance of physical and chemical properties has
made this type of overcoat based on Butvar a leader in the
field for many years.
Surface coatings
The Butvar vinyl acetal resin may be used alone or in
combination with a wide variety of resins to give functional
surface coating compositions. Films which may be air dried,
baked, or cured at room temperature are obtained by proper
compounding. The presence of hydroxyl groups in the
polymer molecule not only enables good wetting of most
substrates but also furnishes a reactive site for chemical
combination with thermosetting resins.
Wash primers
In protective coatings for metal, the best known vinyl
acetal application is in “wash primers,” also referred to
as “metal conditioners.” Compared with other corrosion
inhibiting materials, wash primers are unique and more
effective because they offer, in a single treatment, several
means of preventing corrosion.These anticorrosive primers
apply easier, adhere better, and dry faster than the more
conventional materials.
The action of wash primers over steel, for example, is as follows:
• First, an iron oxide and zinc phosphate film, similar to that
formed in the common phosphating processes, is deposited
on the metal.
• Second, these wash primers provide a continuous supply
of chromate ions to repair pin holes in the phosphate film,
eliminating the need for a special chromate rinse.
• Third, the polyvinyl butyral film is chemically bound in the
inorganic layers through a chromium complex, providing
additional mechanical protection to the metal surface.
In effect, this type of primer actually phosphatizes the metal
at the surface, supplies a corrosion inhibiting pigment in a
tenaciously adhering binder, and dries to take most topcoats.
Wash primers are widely used on a variety of metal
structures, such as storage tanks, ships, airplanes, etc.
Highway departments also have shown a keen interest
in these coatings for bridges, dam locks, and in particular,
highway guardrails. In finishing trucks or house trailers
fabricated of phosphated or galvanized steel, or aluminum,
wash primers provide corrosion resistance and adhesion
under single-coat styrenated alkyd and other modified
alkyd enamels. On metal that is subject to immersion and
corrosion conditions, wash primers are specified under
urethane and vinyl topcoats.
Military specification wash primers
The U.S. Navy Bureau of Ships has long recognized the need
for the use of the wash primer as a surface pretreatment for
metals prior to subsequent painting. Military Specification
DOD-P-15328D entitled Primer, Pretreatment is required to
be used on all metal surfaces. This primer is a two-package
system containing Butvar B-90 in a solvent system consisting
of normal butanol and either ethanol or isopropanol. By
comparison, the Department of the Air Force and the U.S.
Navy Bureau of Naval Weapons have approved a slightly
different pretreatment formulation designated Coating
Compound, Metal Pretreatment, Resin-Acid MIL-C-8514C
(ASG). This system specifies the use of either Butvar B-76 or
Butvar B-90 in a solvent system consisting of butanol and
ethanol. Specific details of both wash primer systems can be
found in the particular specification involved.
17
Nonspecification wash primers:
B-1030 with Butvar
Single-package wash primer:
B-1011 with Butvar
Wash primer B-1030 formulation is a two-package system
based on Butvar B-76 resin and a thermosetting phenolic
resin. This formulation was designed to give higher early
water resistance than the well-known military specification
wash primers. Coatings based on formulation B-1030 exhibit
reduced tendency to blister and to lose adhesion in high
humidity. The B-1030 formulation also has nonsettling
characteristics. In contrast to the older wash primer
formulations, B-1030 does not display hard pigment settling
of the base grind.
Wash primer B-1011 is a clear, green single-package primer
also known as a “reacted” wash primer. Based on Butvar
B-90 resin, it has excellent stability in both concentrated
and diluted forms and air dries to clear glossy films of very
low color. Films of the primer possess good adhesion to
steel, phosphated steel, galvanized steel, brass, copper, wood,
stainless steel, and chrome plate. Although designed to
enhance adhesion, this coating also functions as a corrosioninhibiting primer for a variety of topcoats but in many cases,
may afford protection as the sole coating.
The thermosetting resin content of the B-1030 formulation
not only increases water resistance but also contributes to
reduced solvent sensitivity. Thus, good adhesion and corrosion
resistance are retained under alkyd, alkyd-nitrocellulose,
acrylic, and vinyl topcoats, and also under epoxy, urethane,
polyvinyl acetate, and alkyd melamine topcoats.
Table 11. Wash primer B-1030 with Butvar
A. Base grind
Percent by weight
1. To a solution of:
2. Add:
Butvar B-76
1.24
Ethanol, 95%
9.35
Methyl ethyl ketone
9.97
Basic zinc chromate pigment
11.52
™
Celite 266
4.82
Butvar B-76
7.39
Ethanol, 95%
23.08
Methyl ethyl ketone
24.63
Santolink® EP 560
8.00
3. Grind to Hegman fineness of 6, N.S. scale
4. Add solution of:
Total
100.00
5. Grind for 30 minutes and package
B. Reducer
Percent by weight
Phosphoric acid, 85%
7.50
n-butanol
92.50
Total
100.00
Mix for several minutes and package
Reduced primer properties (Pigment grind to reducer; 1:1 by volume)
NVM
19%
Weight per gallon
7.5 lb
Coverage
533 sq. ft./gal at 0.3 mils dry
Pot life
8–12 hours
18
Table 12. Wash primer B-1011 with Butvar
Material
A.
B.
C.
Percent by weight
Acetone
44.40
Anhydrous ethanol
36.30
Butvar B-90
11.00
85% phosphoric acid (U.S.P.)
0.72
Water
6.48
Chromic acid (99 + %)
0.37
Water
0.73
Total
100.00
Properties
NVM
12%
Viscosity
21 sec., No. 4 Ford cup
Lb/gal
7.0
Coverage
384 sq. ft./gal at 0.3 mils dry
Chromate-free wash primers with Butvar
borate, or borophosphate, are suggested. Substitution of
these pigments for zinc chromate on an equal weight or
volume basis are suggested starting points for reformulation.
A chromate-free wash primer based on U.S. Government
specification DOD-P-15328D is shown in Table 13.
Traditional wash primer formulations have generally
employed zinc chromate as the anticorrosive pigment. Due to toxicity concerns associated with chromates,
alternative anticorrosive pigments, such as zinc molybdate,
Table 13. Sherwin-Williams chromate-free wash primer
A. Base grind
DOD-P-15328D
Moly-White
X92
Butvar**
B-90, B-98
Pounds
Pounds
Gallons
Butvar B-90
56.0
56.0
6.10
n-butanol
125.0
125.0
18.48
Isopropanol, 99%
353.0
353.0
53.80
Moly-White X92
—
39.7
1.70
Basic zinc chromate
54.0
Magnesium silicate, MP40-27
8.0
1.70
8.0
0.34
Furnace black
0.6
0.6
0.34
Water, DI
15.0
15.0
1.80
—
—
82.26
Phosphoric acid, 85%
28.0
28.0
2.0
Water, DI
25.0
25.0
3.0
Isopropanol, 99%
99.0
99.0
15.0
—
—
20.0
B. Reducer
Alternative chromate-free pigments are PhosGuard® J-0800 from Mineral Pigments Corporation and Borogard ZB
from U.S. Borax.
19
Metal coatings
Butvar® resins are used in a wide variety of metal coating
applications in combination with other resin types, such
as phenolics, epoxies, isocyanates, melamines, ureas, etc.
When used with these various modifying resins, Butvar can
improve coating uniformity, minimize cratering, improve
adhesion, and increase coating toughness and flexibility.
These resin combinations can be compounded to produce
baked coatings with good chemical resistance, which also
will withstand postforming. Applications of such coatings
can be made by conventional methods including brush,
spray, dip, fluidized bed, etc. End-use applications include
drum and can linings, as well as the wide variety of metallic
substrates, which are coated by the fluidized bed technique.
Curable coatings containing Butvar resin may be formulated
to meet the extractability requirements of the U.S. Food and
Drug Administration for indirect food additive uses.
Metal coating 2009 is one example of the use of Butvar in combination with other resins—in this case phenolic and epoxy—to produce an excellent coating. This particular
combination provides excellent abrasion resistance,
toughness, flexibility, adhesion, and chemical resistance.
Specific application tests have shown that this system
should make outstanding can or drum linings.
20
Table 14. Metal coating 2009
Material
Percent by weight
Diacetone alcohol
17.4
n-butanol
17.4
Ethanol, 95%
7.7
Xylol
34.7
Santolink® EP 560
5.1
Epon 1007F
13.0
Butvar® B-90
2.0
10% phosphoric acid (in above solvents)
2.7
Total
100.0
™
Properties
NVM
20%
Application: spray or roller
Cure cycle sequence: Room temperature. Drying 15 minutes, followed by 30
minutes at 190˚F and 20 minutes at 400˚F.
Wood finishes
Knot sealers
Protective wash coats and sealers
The polyvinyl butyral resins are excellent barriers to bleeding of terpenaceous matter from knots, heart wood,
and rosin ducts. The Western Pine Association has developed a superior knot sealer based on Butvar. The system consists
of a combination of Butvar and phenolic resins (Table 16).
Butvar® resin is widely used as a component of wash
coats and sealers in wood-finishing operations. It provides
good holdout, intercoat adhesion, moisture resistance,
flexibility, toughness, and impact resistance to the coating
system. In addition, the wood substrate is protected against
discoloration when Butvar is used in the finish. Combinations
involving nitrocellulose, shellac, and shellac ester along with
other resin types are used with Butvar under many of the
common topcoats (Table 15). Butvar is particularly effective
for improving the holdout of polyester and polyurethane
coatings, as well as protecting the wood substrate against
color changes caused by light.
The following starting formulation is representative of the
kind of wood sealer or wash coat that can be compounded
from Butvar.
T
able 16. Western Pine Association knot sealer, WP578
Material
Percent by weight
Butvar B-90
3.3
™
Durite P-97
40.0
Ethanol, 95%
56.7
Total
100.0
Properties
NVM
23.3%
Application: brush
Table 15. Sealer/wash coat with Butvar
Material
Percent by weight
Butvar B-98
6.1
Nitrocellulose, RS , ¼ second
9.2
Butyl acetate
32.9
Ethanol, anhydrous
5.5
Isopropanol, 99%
10.9
8.8
Xylol
13.3
™
Toluol
13.3
Total
100.0
The preceding formulation is designed for brush application.
However, it has been adapted to application from an aerosol
spray can, giving the same outstanding performance as the
brush applied system.
Properties
NVM
Viscosity
12.5%
20 sec., No. 4 Ford cup
Cure cycle sequence: Room temperature. Drying 15 minutes, followed by
30 minutes at 190˚F and 20 minutes at 400˚F. Application: Spray or roller
21
Adhesives
Structural adhesives
Structural adhesives originally were developed for use in the aircraft industry to replace rivets and other methods of
joining and fastening. Refinements in formulating structural
adhesives led to their use in bonding brake linings, in the
electrical and electronic industries on printed circuits, in
structural composite fiber binders for aerospace or
antiballistic applications, and in the architectural field for
the manufacture of interior and exterior curtain walls.
Combinations of Butvar® resin with thermosetting resins
have long been in use in bonding aircraft components—
in fact, the system was the first synthetic resin adhesive to be used for bonding metals in structural applications.
Phenolic resins
In some structural adhesive formulations, Butvar resins are
combined with alkaline catalyzed phenolic laminating resins,
such as Durite™ LS-433 or Plyophen™ 22-023. Compared with
other general types of structural adhesive systems (epoxyphenolic and synthetic rubber-phenolic), the PVB-phenolic
gives the highest shear strength values at temperatures up
to 250˚F. Other outstanding properties of the PVB-phenolic
system include high peel strength at very low temperatures,
excellent dielectric properties, and exceptionally good creep
resistance as measured by the ability of the bond to carry
sustained loads for extended periods of time.
Polyvinyl butyral-phenolic ratios of from 10:1 to 10:20 have
been used successfully for structural adhesives, although 10:5
seems to be the best ratio for a compromise of properties. As the amount of phenolic is reduced, the cured adhesive
becomes more flexible, and in most cases, peel strength
increases. In addition, because of the increased thermoplastic
nature of the system, the high temperature shear strength is
reduced. These effects, i.e., increased peel and reduced high
temperature shear strength, occur when the cure time is
shortened or the cure temperature is lowered.
Structural adhesives based on polyvinyl butyral resins can be applied as a solution, an unsupported film, a supported
film on paper or cloth, or as a mixture of liquid and solid.1
See U.S. Patent 2,499,134.
1
22
In a solution adhesive system, the choice of solvents is
important both for viscosity control of the solution and
proper drying and filming characteristics. Proper drying of
the adhesive film is very important, as only a small amount
of residual solvent can affect greatly the various final
properties. Yet the solvent cannot be so volatile that
blushing occurs. Sprayed films are much more sensitive to
blushing than brushed or roller-coated films. For brushing,
solvents in the boiling range of 75˚ to 100˚C are advised
because they can be removed by air drying and then force
drying for 30 to 60 minutes at 105˚C. Solutions for spraying
can tolerate small amounts of higher boiling solvents, such
as xylene and butanol.
Viscosity of the adhesive solution affects the smoothness
and the thickness of the final brushed or sprayed film. For brushing, the proper viscosity is obtained at the
following solids content (with a 10:5 PVB:phenolic ratio):
Butvar B-90, 21%; Butvar B-72, 16% to 18%. For spraying,
the solids content should be reduced to obtain nonblushing,
noncobwebbing films.
Epoxies and other thermosetting resins
Butvar resins are compatible with many epoxy resins and
can confer such improvements on epoxy-based systems as
increased impact resistance and peel strength. In epoxy
systems, as in phenolic systems, the vinyl acetal resins can
serve as both coreactant and flexibilizer.
The addition of small amounts of compatible plasticizer to
an adhesive system combining a vinyl acetal resin with a
thermosetting resin increases the flexibility and impact
resistance of the bond with only slight sacrifice in high
temperature shear. This increased flexibility is most evident
when peeling thick adherends and at high peeling speeds.
The tack or heat seal temperature of the uncured adhesive
also is appreciably lowered by the addition of plasticizer.
Adhesives with pressure sensitive properties in the uncured
state can be developed which, when cured, will have
temperature shear bond strength of more than 1,000 psi.
High-strength bonding procedure
Performance characteristics
For high-strength bonds, substrate cleaning is very
important. Usually the removal of surface contamination,
such as oil film, dust, etc., is sufficient. Such cleaning
normally is achieved by solvent or by detergent wash.
However, for highest strength bonds, chemical surface
preparation is employed. The following metals require the preparation noted:
The quality of a structural bond for a particular application
is usually described in terms of its shear strength, peel
strength, creep properties, fatigue strength, and
environmental resistance. In aircraft applications, high
temperature shear, fatigue resistance, creep, and oil and gas
resistance are most important. In printed circuits, peel
strength, blister resistance, and dielectric properties are of
primary importance. For architectural use, high peel strength
and long-term resistance to dead load and extremes of
atmospheric environment are the outstanding requirements.
Adhesives based on Butvar® resins excel in all of these
characteristics.
• Aluminum alloys—acid oxidation
• Copper—alkaline oxidation
• Steel—a pickling bath to remove oxide scale
Care should be taken to avoid touching the cleaned panels
or exposing them to any contaminated atmosphere. The
adhesive should be applied to the cleaned surface as soon as possible.
A dry glue line of 3 to 10 mils has been found quite
satisfactory. With solvent systems, this thickness usually can be achieved with 2 to 4 brushed coats of adhesive on
each adherend. With very thin glue lines, even pressure must
be applied to the laminate during cure so that consistent
bonds be obtained. Thicker glue lines have greater flow and
absorb unequal curing pressures.
The requirements and methods for testing adhesives for
aircraft applications are presented in Military Specifications
MM-A-132 and MIL-A-25463-30. Test methods for
architectural and printed circuit applications are contained
in various ASTM and NEMA specifications.
Adhesive strengths
Typical test values for phenolic bonds of Butvar resins
measured by these techniques are in Table 17.
Table 17. Adhesives strengths
PSI shear strength at
180ºF
250ºF
300ºF
Vinyl acetal
Amount of
phenolic, phra
Cure
72ºF
Peel at 72ºF
lb/in. width
Butvar B-72
50
30 min, 330ºF
6,000
4,000
1,400
500
25–30
Butvar B-90
50
30 min, 330ºF
5,700
2,800
1,000
—
30–35
Butvar B-72
100
20 min, 300ºF
5,000
3,300
1,100
—
35–40
phr = parts per hundred resin
Test procedures: Shear—aluminum to aluminum as per MIL-A-8431 Peel— 6-mil aluminum to 64-mil aluminum peeled at 5 inches per minute
a
23
Hot melt adhesives
Advantages as textile coating
Butvar® makes an excellent base for hot melt adhesives
even where difficult-to-bond surfaces are involved. The many
types of Butvar resins allow the best match to individual
applications. For example, Butvar B-98 can be formulated to
produce a hot melt with low viscosity characteristics. B-72
can be used to produce an adhesive with similar chemical
properties but higher viscosity. Other types, such as B-76,
are available to produce adhesives where less crosslinking is
desirable.
The advantages of Butvar as a textile coating resin stem
from the following properties:
Table 18 shows a starting formulation for a hot melt based
on Butvar.
Table 18. Typical hot melt formulation
Material
Parts by weight
Butvar B-76
10
Santicizer® 160
10
Castorwax
35
Poly-Pale™ Ester #1
26
™
Staybelite Ester #10
19
Total
100
™
Textile coatings
One of the unique uses of Butvar polyvinyl butyral resin is in the textile coating field. It can be compounded to make
fabrics water resistant and stain resistant without noticeably
affecting the appearance, feel, drape, and color of the fabric.
Tablecloths, drapes, slipcovers, shower curtains, aprons,
smocks, and children’s bibs are some of the more common
items which can be prepared. Outside the home, fabrics
coated with Butvar serve as rainwear, porch furniture
upholstering, awnings, and beach accessories.
Butvar, which provides a transparent film, can be applied to practically all common fabrics. Cotton, wool, silk, nylon,
viscose rayon, and other synthetics can be successfully
coated. As a rule, almost any fairly tight woven fabric with a flat surface can be made water and stain resistant with a coating based on Butvar.
24
• Transparency: Butvar can be made into a clear, colorless
coating with excellent light resistance and aging
characteristics.
• Adhesion: After curing, Butvar adheres readily to practically
all fabrics, including those normally considered difficult to
coat, such as nylon, viscose rayon, and fiberglass.
• Hand and appearance: A coating with Butvar has the soft,
warm, flexible feel of an uncoated fabric, yet possesses all
the functional characteristics of coated fabrics.
• Functional properties: Butvar combines these attributes
with functional properties comparable to those of the best
textile coating materials in the field. During the drying and
curing operations, Butvar is transformed to an elastomer
which becomes a permanent part of the fabric.
Fabrics coated with properly compounded and cured Butvar
have outstanding softness and flexibility without tackiness
of low softening temperatures. They have excellent chemical
and water resistance. Films of Butvar resin are tough and will
resist abrasion and wear. Coatings can be applied from high
solids solutions made with common solvents. Clear coatings
with Butvar may be applied from solutions of up to 35%
solids; pigmented coatings may be as high as 45% solids.
Solutions of Butvar are ideally suited to coating with either
rubber or pyroxylin spreaders. Solids content can be high and the solvents fast evaporating. The material will flow well
after being spread. For most applications, a light coating
averaging 1½ oz dry to the square yard is recommended.The
solution of Butvar, which can be prepared in a solvent
mixture of alcohol and naphtha, is applied in generally two
to five passes, depending on the type of fabric and the
coating operation. This is followed by a flat topcoat to
remove gloss and tack normally associated with coated
fabrics. Usually two topcoats are required for a smooth,
skip-free coating.
The first two coats should be low in viscosity for proper
penetration of the coating into the fiber interstices. The
relationship between depth of penetration and coating
viscosity will necessarily depend on the fabric construction
and must be determined on the basis of trials. If an
excessively high coating viscosity is used for the initial coats, peel adhesion, Mullen, and other physical test
properties will suffer. Experience has shown that superior
coatings are produced by many thin coats rather than by a few heavy applications.
Butvar is unique among vinyl resins in its ability to be cured
in a manner somewhat analogous to rubber. Curing improves
both heat and solvent resistance and adhesion to the fabric.
Curing Butvar is accomplished by incorporating crosslinking
resins, such as urea, phenolics, melamines, and isocyanates.
Since the reaction involves the hydroxyl groups on the
chain of Butvar, only a small amount of a modifying resin
is needed to increase substantially the heat and solvent
resistance of the Butvar resin.
A formulation incorporating such a crosslinking resin is
shown in Table 19.
Table 19. Typical textile coating formulation
Material
Parts by weight
Butvar B-72
48.0
Tricresyl phosphate
48.0
Ethanol 95%
84.2
Toluene
64.8
Water
8.0
Resimene® AQ-7550
3.5
p-toluene sulfonic acid
0.7
p-nonyl phenol
0.2
Coated stocks are cured after all coats have been applied.
Premature curing of any coat due to overheating will reduce
the adhesion of subsequent coats. The time required for
curing will depend on the resins and the catalysts employed
and on the temperature of the curing oven. Cure time will
vary from approximately one hour at 250˚F to five minutes
or less at 350˚F.
Coatings with Butvar have been cured satisfactorily in festoon
dryers at 200˚F, in steam heated ovens at 300˚F, in gas ovens,
and even dryer cans. In all cases, overheating should be
avoided to prevent loss of plasticizer and stiffening.
A properly coated and cured fabric will be water resistant;
will be resistant to ink stains, coffee, tea, cooking oils, and
fats; and will have excellent washability. Most soilings can be
wiped away with a damp cloth. Should the uncoated side
require laundering, neutral soap and warm water should be
used. The coated fabric can be ironed on the uncoated side.
Coatings based on Butvar cannot be dry cleaned. Such
treatment will remove the plasticizer and leave a stiff, harsh
coating which will break on flexing.
Ceramic binder applications
Compounding
1. Combine solvents and plasticizer.
2. Add Butvar B-72 with stirring; heat if desired to speed solution.
3. Cool batch, blend in p-nonyl phenol, Resimene AQ-7550, and
p-toluene sulfonic acid in that order.
Compound properties
Percent solids
39%
Viscosity (freshly made)
ca 70,000 cps
Viscosity (24 hours)
ca 75,000 csp
Cure cycle sequence: Room temperature. Drying 15 minutes, followed by 30
minutes at 190˚F and 20 minutes at 400˚F. Application: Spray or roller
Butvar polyvinyl butyral resins are recognized as the binder of choice in the processing of ceramic tape cast
materials. The resin imparts excellent green strength and
flexibility to the ceramic tape. It is compatible with many
common solvents and plasticizers and burns out cleanly
during sintering.
Butvar resins also are used as a binder medium in thick film processing. Butvar is formulated in the solvent vehicle
used to deposit the circuit pattern on the ceramic surface.
The primary advantages of using Butvar resins are their
solubility in a wide range of solvents and uniform adhesion
to conductive metals.
25
Tape casting
Butvar is regarded as the binder of choice for the ceramic
tape casting process due to the following benefits:
• Butvar resins provide excellent green strength to the
unified tape.
- Butvar allows multiple tapes to be laminated in the green stage.
- Low Butvar concentrations allow for higher density
substrates after firing.
• Butvar is soluble in many volatile yet inexpensive solvents.
- Flexibility in choosing Butvar product types and load
levels for a wide range in binder solution viscosities and,
therefore, ceramic slip viscosities.
• Butvar is compatible with many of the plasticizers used in ceramic systems.
- Choose from dialkyl phthalates, benzyl phthalates,
adipates, or phosphates commonly used.
• Butvar burns out cleanly with a minimum of warpage to the fired part.
- The product shrinks uniformly.
- Low gel content minimizes surface defects.
• Butvar has natural dispersing properties and is compatible
with common dispersing agents, such as fish oils or
phosphate esters.
The medium-to-low molecular weight resins, Butvar B-76, B-79, B-90, or B-98, are recommended for use in tape casting processes.
A typical tape casting formulation based on 100 gms of solid ceramic powder is shown in Table 20.
Table 20. Typical tape casting formulation
Component
Alumnina
Parts by weight
100.0
Butvar B-79
5.0
Santicizer® 160
4.3
Blown Menhaden Oil Z-3 visc.
2.0
Toluene
14.4
MEK
14.4
26
Premix the fish oil in the toluene and MEK and add to ball
mill. Add Alumina and ball mill for one hour. Add Santicizer
160 and Butvar B-79. Mill an additional 24 hours. Pour, de-air for several minutes, and cast.
• Additional Butvar can be added to most formulations to
improve interfilm lamination in a multilayer substrate.
• A microfiltration system is generally used with
binder/solvent systems. A five micron or finer filter is
recommended.
Thick films
Butvar resins can be used as the binder medium in vehicle
formulations for thick film pastes. Our lowest molecular
weight resins, Butvar B-79 and B-98, are recommended for
either silk screen or steel screen processes. The advantages of using Butvar in thick films include:
• Butvar is an excellent binder and dispersant for the
conductive metals used in thick films.
• Thick films with Butvar can be cofired with the green tape in laminated ceramic substrates.
• Binder compatibility problems are minimized for cofiring
systems when Butvar is used in both thick film processing and as the binder in the ceramic tape casting process.
Table 21. Thermal properties
Units
Test
method
Butvar
B-76
B-79
Butvar
B-90
B-98
C
DSC
62–72
72–78
In nitrogen
%
TGA
<2.0
<3.0
In air
%
TGA
<0.75
<0.75
Glass transition
temperature (Tg)
Ash content at 550ºC
The apparent glass transition temperature (Tg) was
determined by Differential Scanning Calorimeter (DSC). The Thermal Gravimetric Analysis (TGA) was a weight loss
versus temperature profile conducted at a heating rate of
10˚C/min.
Graph 11. Butvar® resin thermolysis profiles:
Thermal Gravimetric Analysis (TGA)
In nitrogen
100
90
80
70
60
40
30
20
10
0
Butvar resins have been used in printing ink formulations
for many years. All Butvar resins are alcohol soluble and
are often used in solvent-based gravure and flexographic
ink formulations to improve flexibility, adhesion, and
toughness. The solubility characteristics of Butvar B-79 and
100
B-76 in aromatic and other fast-drying solvents allow for
90
compounding at low concentrations in high speed, high
quality80printing applications. These properties have also
70 Butvar to be used in ink formulations for thick film
enabled
conductive
pastes, printer ribbons, and pen inks, as well as in
60
the manufacture
of offset printing plates and other printing
50
technology
apparatus.
40
Weight (wt percent)
Weight (wt percent)
50
Toners and printing inks
50 100 150 200 250 300 350 400 450 500 550
Temperature (ºC)
Heating rate: 10ºC/min
Butvar30also serves the toner industry as a secondary binder.
20 butyral is added to the formulations to increase
Polyvinyl
10 and to improve film integrity over the fuser roll.
viscosity
The overall
toughness of Butvar enhances the integrity 0
100 150 200 250 300 350 400 450 500 550
of the toner50
during
the milling process and extended machine
Temperature
(ºC) the level ofHeating
rate: 10ºC/min
operation.
This minimizes
fines without
detracting
from the flow properties.
Graph 12. Butvar® resin thermolysis profiles:
Thermal Gravimetric Analysis (TGA)
In air
100
90
80
70
60
Weight (wt percent)
50
40
30
20
10
0
50 100 150 200 250 300 350 400 450 500 550
Temperature (ºC)
Heating rate: 10ºC/min
27
Storage and handling
Storage
Quality control
Environments of high heat and humidity should be avoided.
To obtain the outstanding quality characteristics of
Butvar, Solutia maintains statistical process control over
the manufacturing process. In addition, to ensure that
you receive highly uniform material with each shipment,
the finished product is analyzed in detail to be certain it
conforms to our rigid specifications.
Toxicity and FDA status
Butvar® resins are regulated by the U. S. Food and Drug
Administration under parts of 21 Code of Federal Regulations
for use as indirect food additives. Butvar resin also has been
subjected to acute toxicity and mutagenicity studies. Details
on specific coverage of individual studies are available on
request.
Table 22. Packaging information
Container type
61-gallon fiber drum
28
B-72
B-90, B-76
B-98, B-79, B-74
145 lb (66 kg)
140 lb (63 kg)
135 lb (61 kg)
Material sources
Product designation
Owner and/or supplier
Product designation
Owner and/or supplier
Araldite 6069
Ciba Geigy Corporation
Linseed oil
Arista Chemical Inc. Reichhold Chemicals, Inc.
Basic zinc chromate
Lansco Colors
Rockwood Pigments NA, Inc.
Magnesium silicate MP40-27
Specialty Minerals
Beckosol 11-035
Reichhold Chemicals, Inc.
Methyl acetate
Eastman Chemical Company
Blown Menhaden Oil Z-3 visc.
Werner G. Smith Inc.
R.E. Mistler, Inc.
Methyl alcohol
Air Products and Chemicals Inc.
Methyl ethyl ketone
Shell Chemical Corporation
Borogard ZB
U.S. Borax
2-Butoxyethanol (Eastman™ EB solvent)
Methylon 75-108
OxyChem
Butvar® resins
Moly-White X92
Sherwin-Williams Chemical
Butyl acetate
Naphtha
Butyl alcohol
Nitrocellulose RS, SS
Dow Wolff Cellulosics
Butyl benzyl phthalate
Ferro Corporation
OxyChem 02620, 92600, 29107
OxyChem
Castor Oil #1 (raw), #15, #30, #40
CasChem Inc.
p-nonyl phenol
Boddin Chemiehandel
Castorwax
CasChem Inc.
Paraplex® RGA-8
HallStar
Celite 266
Imerys Filtration
Pentalyn H
Cellulose acetate
PhosGuard® J-0800
Cellulose acetate butyrate
Phosphoric acid, 85% U.S.P. Astaris
Chlorinated rubber
Hercules Inc.
Plyophen 22-023
OxyChem
Chromic acid (chromium trioxide)
J.T. Baker Inc.
Poly-Pale ester #1
Hercules Inc.
DC 840
Dow Corning Corporation
Pycal 94
ICI Americas Inc.
DCZ 6018
Dow Corning Corporation
Desmodur AP stabil
Bayer MaterialScience
Resimene® 717, 730, 741, 881
AQ-7550 and 918 Cytec Ind.
Diacetone alcohol
SP-1044 resin
Schenectady Chemicals Inc. Dibutyl phthalate
BASF
Santicizer® plasticizers
Ferro Corporation
Dibutyl sebacate
HallStar
Santolink® EP 560
Cytec Ind.
Dihexyl adipate
Ferro Corporation
Shellac
RPM International Inc. Dimethyl esters
Invista
Staybelite ester #10
Dioctyl phthalate
Tributyl citrate
Morflex Chemical Company
Duraplex 11-804
Reichhold Chemicals, Inc.
Tricresyl phosphate
Durite P-97, LS-433
Borden Chemical Company
FMC Corporation Akzo Chemicals Inc. Epi-Rez 540-C
Solvay
Epon 1001F, 1007F
Momentive
Triethylene glycol di-2-ethylhexanoate
(Eastman™ TEG-EH)
2-ethylhexyl diphenyl phosphate
Ferro Corporation
Triphenyl phosphate
Triway
Flexricin-P3
CasChem Inc.
Vinyl chloride copolymer VAGH,VAGD (UCAR solution vinyl resin)
Dow Chemical Company
Furnace black
Columbian Chemicals
Vinsol
Pinova Solutions
Hercolyn
Pinova Solutions
Xylol (xylene)
Exxon Company, USA
Isophorone
Dow Chemical Company
Zinc borate
U.S. Borax Isopropanol
Zinc borophosphate
Ketjenflex 8, 9S, MH
Axcentive
Zinc molybdate
Sherwin-Williams Chemical
29
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.
MetLife 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
Although the information and recommendations set forth herein are presented
in good faith, Eastman Chemical Company and its wholly owned subsidiary
Solutia Inc. make no representations or warranties as to the completeness or
accuracy thereof. You must make your own determination of their 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. Nothing contained herein is to be construed as a recommendation
to use any product, process, equipment, or formulation in conflict with any
patent, and we make no representations or warranties, express or implied, that
the use thereof will not infringe any patent. NO REPRESENTATIONS OR
WARRANTIES, EITHER EXPRESS OR IMPLIED, OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE, OR OF ANY OTHER NATURE ARE MADE
HEREUNDER WITH RESPECT TO INFORMATION OR THE PRODUCT TO WHICH
INFORMATION REFERS AND NOTHING HEREIN WAIVES ANY OF THE SELLER’S
CONDITIONS OF SALE.
Safety Data Sheets providing safety precautions that should be observed when
handling and storing our products are available online or by request. You
should obtain and review available material safety information before handling
our products. If any materials mentioned are not our products, appropriate
industrial hygiene and other safety precautions recommended by their
manufacturers should be observed.
© 2013 Eastman Chemical Company. Eastman and The results of insight are
trademarks of Eastman Chemical Company. Butvar is a trademark of Solutia
Inc., a subsidiary of Eastman Chemical Company. As used herein, ® denotes
registered trademark status in the U.S. only. All other trademarks are the
property of their respective owners.
BVR-001
11/13