Butvar Properties and Uses

Pub. No. 2008084E
(Supersedes 2008084D)

®

Butvar

P O LY V I N Y L B U T Y R A L R E S I N P R O P E RT I E S & U S E S

Coatings Performance Materials by

CONTENTS

Introduction Properties
12

Chemistry

2

Properties Tables

3

Product Types

6

Butvar:The Right Resin Solutions Compatibility
6
13 15 15 15 16 16 16 17 17 17 17 17
Insolubizing Reactions Reaction With Phenolics Reaction With Epoxies Reaction With Dialdhehydes Reaction With Isocyanates Reaction With Melamines
Applications
Wire Enamels Surface Coatings Wash Primers Military Specification Wash Primers Non-specification Wash Primers:
B-1030 With Butvar
Single Package Wash Primer:
B-1011 With Butvar
Chromate-free Wash Primers With Butvar Metal Coatings
18 18 19 20 21 21 21 22 22 22 22 23 23 23 24 24 24 25 26 26 27 28 28 28 28
Wood Finishes
Protective Wash Coats and Sealers Knot Sealers
Adhesives
Structural Adhesives Phenolic Resins Epoxies 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
Storage and Handling
Storage Toxicity and FDA Status Quality Control
Material Sources Worldwide Sales Offices
Inside Back Cover
Back Cover

INTRODUCTION

olyvinyl butyral resins are employed in a wide array of industrial and commercial applications. These unique resins offer impressive performance,

USES

Some of the applications in which Butvar is a vital ingredient include:

P

as well as outstanding versatility.
ꢀ Ceramic binders

ꢀ Inks/dry toners ꢀ Wood coatings

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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.
ꢀ Wash primers ꢀ Composite fiber binders ꢀ Structural adhesives ꢀ Other diverse uses

Solutia offers six grades of Butvar resin 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.
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 Solutia 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.

® Registered trademark of Solutia, Inc.

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PROPERTIES

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 groups, acetate groups and acetal groups.The final product may be represented by the following stylized structure:

CHEMISTRY

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
H
H

R

C + R¹OH

R

C

OR + R¹OH

R

C( OR¹)₂+ H₂O

O

OH

Alcohol

Aldehyde

Hemiacetal

Acetal

H

CH₂

C
H

CH₂

C

CH₂

C

CH₂

C

O

OH

O

C

O

H

C₃H₇

CH₃

A

B

C

PV Butyral

PV Alcohol

PV Acetate

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TABLE 1

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Physical Properties of Butvar Resins (white, free-flowing powder)

ASTM

Property

Units

Method

B-72

B-74

B-76

B-79

B-90

B-98

*Volatiles, max

%

3.5

3.0

5.0

Molecular wt. (weight

average in thousands)

–

(1) (2) (2) (3)

170-250

120-150

90-120

500-1,000
200-450 18.0-28.0
50-80
100-400 75-200 9.0-16.0
70-100
600-1,200
200-400 13.0-17.0
40-70
200-400 75-200 6.0-9.0
Solution viscosity

15% by weight

cp.

cp. cp.
7,000-14,000 3,000-7,000
Solution viscosity

10% by weight

1,600-2,500

170-260
800-1,300 37.0-47.0
*Ostwald solution viscosity

Specific gravity 23˚/23˚ ( 0.002)

–

D792-50

1.100

1.0
1.100
1.0
1.083
1.0
1.083
1.0
1.100
0.9
1.100

0.8

Burning rate

ipm

D635-56T

Refractive index ( 0.0005)

–

D542-50

1.490

0.5
1.490
0.5
1.485
0.3
1.485
0.3
1.490
0.5
1.490

0.5

Water absorption (24 hours)

%

D570-59aT

*Hydroxl content expressed as % polyvinyl alcohol

–––
–––

17.5-20.0
0-2.5
17.5-20.0
0-2.5

11.5-13.5

0-2.5
88

11.0-13.5

0-2.5 88

18.5-20.5

0-1.5
18.0-20.0
0-2.5
Acetate content expressed as % polyvinyl acetate

Butyral content expressed as % poly-

vinyl butyral, approx.

80

*Specification properties

Percent Solids
Temperature

Product

Solvent

(˚C)

All properties were determined by ASTM methods except the following:
Anhydrous Methanol
ꢁ 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-72

7.5

20

SD 29

Ethyl Alcohol

B-76, B-79

5.0

25

ꢁ Solution viscosity was determined in 15% by weight solutions in 60:40 toluene: ethanol at 25˚C, using a BrookfieldViscometer. Also in 10% solution in 95% ethanol @ 25˚C using an Ostwald-Cannon-FenskeViscometer.
B-74, B-90, B-98
Anhydrous

Methanol

6.0

20

† P. Dublin, ed., Microdomains In Polymer Solutions (NewYork: Plenum Press, 1985),
ꢁ Ostwald solution viscosity for each product type measured with an Ostwald-

pp. 101-119.
Cannon-FenskeViscometer.The solvents and solids levels used are as follows:

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PROPERTIES

TABLE 2

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Chemical Properties of Butvar Resins

ASTM

Method

Property

Units

B-72

B-74

B-76

B-79

B-90

B-98

Resistance to:

Weak acids

––––

D543-56T D543-56T D543-56T D543-56T
EEEE
EEEE
EEEE
EEEE
EEEE
EEEE
Strong acids Weak bases Strong bases

Organic solvents:

Alcohols

––––––

D543-56T D543-56T D543-56T D543-56T D543-56T D543-56T
PGEF
PGEF
PFFPPP
PFFPPP
PGEF
PGEF
Chlorinated Aliphatic Aromatic

Esters

F

Ketones

F

Key: E – excellent G – good F – fair P – poor

TABLE 3

Mechanical Properties of Butvar Resins

ASTM
Property

Tensile strength:

Yield

Units

Method

B-72

B-74

B-76

B-79

B-90

B-98

3

10 psi

D638-58T

D638-58T
6.8-7.8 7.0-8.0
6.8-7.8 7.0-8.0
5.8-6.8 4.6-5.6
5.8-6.8 4.6-5.6
6.3-7.3 5.7-6.7
6.3-7.3 5.6-6.6

3

Break

10 psi

Elongation:

Yield

%

%
D638-58T D638-58T

8

Break

70

75

110

100

110

Modulus of

5

elasticity (apparent)

10 psi

D638-58T

D790-59T
3.3-3.4 12-13
3.3-3.4 12-13

2.8-2.9

3.0-3.1

11-12
3.1-3.2 11-12
Flexural strength, yield

3

10 psi

10.5-11.5

Hardness, Rockwell:

ME

––

D785-51 D785-51
115 20
115 20
100
5
100
5
115 20
110 20
Impact strength Izod,

notched 1/2" x 1/2"

ft.lb./in.

D256-56

1.1

0.8

0.9

0.7

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TABLE 4

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Thermal Properties of Butvar Resins

ASTM

Property

Units

˚C

Method

D569-59
(4)

B-72

145-155
72-78

B-74

135-145
72-78

B-76

110-115
62-72

B-79

110-115
62-72

B-90

125-130
72-78

B-98

105-110
72-78
Flow temperature, 1,000 psi

Glass transition

temperature – Tg

˚C

Ash content at 550˚C:

In nitrogen

%

%
(5) (5)
<3.0 <1.0
<3.0 <1.0

<2.0

<3.0

In air

<0.75

Heat distortion

temperature

˚C

D648-56

(6)
56-60
220
56-60
220
50-54
200
50-54
200
52-56
205
45-55
200
Heat sealing

temperature

˚F`

ꢁ Glass transition temperature (Tg) was determined by Differential Scanning

ꢁ 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.
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.

TABLE 5

Electrical Properties of Butvar Resins

ASTM

Property

Units

Method

B-72

B-74

B-76

B-79

B-90

B-98

Dieletric constant:

50 cps

––––

D150-59T D150-59T D150-59T D150-59T
3.2 3.0 2.8 2.7
3.2 3.0 2.8 2.7
2.7 2.6 2.6 2.5
2.7 2.6 2.6 2.5
3.2 3.0 2.8 2.7
3.3 3.0 2.8 2.8

3

10 cps

6

10 cps

7

10 cps

Dissipation factor:

50 cps

––––

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0.0064 0.0062 0.027
0.0064 0.0062 0.027
0.0050 0.0039 0.013
0.0050 0.0039 0.013
0.0066 0.0059 0.022
0.0064 0.0061 0.023

3

10 cps

6

10 cps

7

10 cps

0.031

0.015

0.023

0.024

Dielectric strength (1/8" thickness):

Short time

v/mil

v/mil
D149-59 D149-59
420 400
420 400
480 390
480 390
450 370
400

380

Step-by-step

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PROPERTIES

PRODUCT TYPES

BUTVAR: THE RIGHT RESIN SOLUTIONS

Butvar brand resins generally are soluble in alcohols, glycol ethers and certain mixtures of polar and non-polar 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.

®

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.

As a general rule, the substitution of butyral groups for acetate groups results in a more hydrophopic 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.
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.
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.
Butvar solutions show very marked viscosity increases as resin solids increase.This effect is shown in Graphs 3 through 10.