The unique behavior of SAIB provides a new approach to formulating in plastics... in lacquers... in melt coatings...
IN PLASTICS SAIB speeds p r o c e s s i n g . . . improves properties of m o l d e d a n d ex-
softer than its hardness at room temperature would indicate.
t r u d e d cellulose acetate plastics
W h e n used in c o n j u n c t i o n w i t h dimethyl phthalate and other common plasticizers, SAIB offers processors of cellulose acetate plastics easier dry blending, faster molding and extrusion rates, and improved physical properties. By reducing the cold solvency characteristics of the more active plasticizers during dry blending, SAIB promotes f a s t e r and m o r e even d i s t r i b u t i o n throughout the cellulose acetate mix. SAIB has an extremely high viscosity index (see Fig. 1 ). At 70°C, the viscosity is less than 1,000 centipoises. Below 70°C, a sudden and sharp increase in viscosity occurs. At room temperature, SAIB is a semi-solid. At processing temperatures, SAIB aids in plasticization, r e sulting in faster, more uniform flow through molding and extrusion cylinders. At room temperature, the opposite effect occurs: SAIB stiffens the plastic and increases its surface hardness. This unusual behavior of SAIB permits molding and extrusion conditions applicable to a material one or t w o flows
16A
Tough, flexible melt coatings that do not fume at melt temperatures can be formulated containing up to 70% SAIB. Operating temperatures are reduced, too. In butyrate hot melts, for example, high modification with SAIB permits an application temperature of 275°F. instead of the usual 350°F. In ethyl cellulose compositions, SAIB reduces mineral oil exudation through its solubilizing effect, thus permitting use of greater amounts of oil. In peelable coatings, SAIB maintains flexibility because it improves resistance to exudation. IN LACQUERS SAIB produces high-solids content cellulosic lacquers a t practical
T h e presence of SAIB also increases rigiditv and tensile strength, and decreases weight loss on accelerated aging of cellulose acetate formulations. IN MELT COATINGS SAIB extends p e e l a b l e coatings...lowers application temperatures of hot melts.
T h e excellent permanence, compatibility and stability characteristics of SAIB result in improved hot melt and peelable plastic formulations.
INDUSTRIAL AND ENGINEERING CHEMISTRY
a p p l i c a t i o n viscosities...improves spraya b i l i t y of v i n y l a n d acrylic l a c q u e r s . . . increases a d h e s i o n to M y l a r
polyester
film a n d n y l o n .
T h e high degree of compatibility exhibited by SAIB with virtually all major film-formers coupled with its except i o n a l s o l u b i l i t y in m o s t c o m m o n lacquer solvents (see table in the next column) permits the formulation of high-solids lacquers at practical application viscosities.
SAIB has an average molecular weight of 8>8 and a compact molecular structure. It has an extremely high viscosity index. (At rooi?i temperattire, it is a semi-solid. At 70°C, its vis cosity drops to less than 1,000 cps. At 100°C, it is only 100 cps.) SAIB is light in color and unusually stable to ultraviolet light. It exhibits outstanding hydrolysis and thermal stability. (Less than 0.1% is hydrolyzed after refluxing 96 hours with water. Heated to /7f °C. for a period of 6 days, its color increases slowly to straw yellow, with no appreciable change occnring until after 24 hours of heat-aging.) SAIB is compatible with a wide variety of polymers, modifiers and plasticizers, and is highly soluble in common lacquer solvents. (A 90% solution of SAIB in ethyl alcohol has a viscosity of only ISO cps. at 30°C.)
Viscosity of 5 0 % SAIB Solutions Viscosity of Solutions of SAIB in Ethyl Alcohol at 2S°C.
(Brookfield viscometer, 25°C.)
Solvent Ethyl alcohol Isopropyl alcohol Ethyl acetate η-Butyl acetate Toluene Hexane Methyl ethyl ketone Methyl isobutyl ketone 1-Nitropropane
Viscosity, cps. 8 14 8 9 9 6 6 8 11
To 100,000* at ΙΟΟΐ solids
ΤΰΟ
| « m
N o t e that these data are for 50% solu tions. Let's consider now t h e viscosity of SAIB solutions at higher concentra tions. T h e case for e t h v l alcohol is shown in Fig. 2. Similar viscosity-con centration relationships exist between SAIH and other common lacquer solvents. From this graph it can be seen that at the highest conceivable concentra tion at which SAIB might be used t o modify a lacquer system, its effect on solution viscosity is negligible. Even after much of t h e solvent has evapo rated from the film, SAIB does not hinder flow-out or leveling. W h i l e this b e havior might also be observed with certain plasticizers, SAIB does not ex hibit plasticizing properties.
S
\ 1 \
11 \ \
v.» % SAIB
W i t h nitrocellulose, for example, the Sward hardness of a 50% SAiB-modified film is increased from 65 to 78. Cellulose acetate films also are increased in hard ness upon addition of SAIB. In this case, however, maximum hardness occurs at a concentration of about 25%. W i t h cellulose films other than nitrocellulose and cellulose acetate, high modification produces only a slight decrease in hard ness with no significant change in solu tion viscosity. Lacquers that show very good adhe sion to Mylar polyester film and nylon (and heat scalable, too, if desired) can
be f o r m u l a t e d w i t h SAIB a n d H a l f Second B u t y r a t e . V i n y l a n d a c r y l i c solutions modified with SAIB show im proved sprayability with less cobwebbing tendency. Greater flexibility for SAiB-modified p o l y m e r s c a n b e achieved, if necessary, b y i n c l u d i n g small amounts of Eastman polymeric plasticizerNP-10. Acting as a plasticizer under certain conditions and as resin-modifier o r -extender under others, SAIB is truly a multi-functional material. Its unique behavior, combined with its low color, stability and moderate cost, make SAIB a compound w o r t h looking into now. SAIB is sold both as a 9(Κ^ solution, designated SAIB-90, and in the undiluted form, designated SAIB. For samples and a report on its physical properties and p e r f o r m a n c e , w r i t e t o y o u r nearest Eastman sales office or t o EASTMAN CHEMICAL
PRODUCTS, I N C . , Chemicals
Division, KINC;SPORT, TENNESSEE.
SAIB SUCROSE ACETATE ISOBUTYRATE
E a s t m a n
CHEMICAL PRODUCTS, INC., subsidiary of Eastman
Kodak Co., Kingsport, Term.
SALES O F F I C E S : ' E a s t m a n C h e m i c a l P r o d u c t s , Inc., K i n g s p o r t , T e n n e s s e e ; A t l a n t a ; C h i c a g o ; C i n c i n n a t i ; C l e v e l a n d ; Detroit; F r a m i n g h a m , Massachusetts; G r e e n s b o r o , N o r t h C a r o l i n a ; Houston; N e w York C i t y ; P h i l a d e l p h i a ; St. Louis. W e s t C o a s t : W i l s o n M e y e r C o . , San Francisco; Los A n g e l e s ; P o r t l a n d ; Salt Lake C i t y ; S e a t t l e . Circle No. 24 on Readers' Service Card VOL. 5 2 , N O . 12
·
DECEMBER
I960
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