Alkyl Methoxysilane Water Repellents - Advances in Chemistry (ACS

Alkyl Methoxysilane Water Repellents

HEADLEE LAMPREY and JAMES O. KOEHLER

Downloaded by CORNELL UNIV on October 12, 2016 | http://pubs.acs.org Publication Date: January 1, 1959 | doi: 10.1021/ba-1959-0023.ch021

National Carbon Research Laboratories, Parma, Ohio

A new class of textile water repellents, of the nondurable type, is described. These compounds are long-chain alkyl methoxysilanes, a representative example being distearyl methoxysilane. Besides giving superior repellency performance, these compounds require no elevated temperature curing on the fiber and they give a superior hand to the fabric. Comparative performance data cover spray ratings, rain tests, permeability measurements, durability determinations, and practical service tests. Special attention is given to the application of these new materials to dry-cleaned cloth, which may contain traces of dry-cleaning soaps and detergents.

A series of improved water-repellent compounds has been developed which are suitable for use on textiles, paper, wood, leather, and other materials. They are silane derivatives of the general classes (CH 0) SiR2 and C H O S i H R where R is a longchain alkyl group containing 12 to 18 carbon atoms or more. A preferred compound of the group is distearyl methoxysilane, ( C H ) S i H O C H , or a dimer or trimer thereof. While other methods are available for making this compound on a commercial scale, a convenient method for making it in the laboratory is through the Grignard synthesis. The four steps in this synthesis are (1) conversion of stearyl alcohol to stearyl bromide or chloride, (2) reaction of the latter with magnesium to form the Grignard reagent, (3) reaction of the Grignard reaction with trichlorosilane, and (4) replacement of chlorine by methoxy. The equations are: 3

2

3

l s

3 7

2

2

3

C H OH + IIBr -> Ci H Br + H 0 18

37

8

C H Br + Mg 18

37

37

(1)

2

dry

> C H MgBr ether 18

(2)

37

2C H MgBr + SiHCl -+ (C H ),HSiCl + MgCl 18

37

3

(C H ) HSiCl + CH OH 18

37

2

3

18

37

2

(C H ) HSiOCH + HC1 18

37

2

3

(3) (4)

The product is a white, waxy solid melting in the range between 165° and 170°C. It is insoluble in water, but readily soluble in such organic solvents as naphtha, petroleum ether, benzene, perchloroethylene, and carbon tetrachloride. 225

METAL-ORGANIC COMPOUNDS Advances in Chemistry; American Chemical Society: Washington, DC, 1959.

ADVANCES IN CHEMISTRY SERIES

226

Formulas F o r m u l a s f o r s o l u t i o n s used t o i m p a r t w a t e r r e p e l l e n c y t o c l o t h a r e :


D i s t e a r y l methoxysilane A l u m i n u m isopropoxide S t o d d a r d Solvent

I, % 30 3 67

Π, % 5.0 0.5 94.5

F o r m u l a I i s a c o n c e n t r a t e o r m a s t e r s o l u t i o n w h i c h , w h e n d i l u t e d w i t h five v o l u m e s of S t o d d a r d S o l v e n t , gives F o r m u l a I I . T h e l a t t e r i s t h e w o r k i n g s o l u t i o n u s e d i n m o s t o f t h e tests r e p o r t e d b e l o w . T h e a l u m i n u m i s o p r o p o x i d e i n these f o r m u l a s serves t o fix the s i l i c o n c o m p o u n d m o r e firmly t o t h e f a b r i c b e i n g t r e a t e d . I t m a y be r e p l a c e d , i f d e s i r e d , b y o t h e r c o m p o u n d s s u c h as b u t y l t i t a n a t e o r t e t r a b u t y l o r t h o z i r c o n a t e . A l u m i n u m soaps d o n o t a p p e a r t o w o r k as w e l l i n t h i s c a p a c i t y . I n s t e a d of d i s s o l v i n g the s i l i c o n c o m p o u n d i n a n o r g a n i c s o l v e n t , as i n F o r m u l a I I , one m a y e m u l s i f y i t i n w a t e r , u s i n g a n e m u l s i f y i n g agent s u c h as a m m o n i u m o r m o r p h o l i n e oleate, o r c e t y l d i m e t h y l b c n z y l a m m o n i u m c h l o r i d e .

Test Methods T h e q u a l i t y of f a b r i c s t r e a t e d w i t h w a t e r - r e p e l l e n t finishes i s d e t e r m i n e d b y s u b j e c t i n g t h e m t o s t a n d a r d r e p e l l e n c y tests, fastness tests, a n a i r p e r m e a b i l i t y test, a n d p r a c t i c a l d r y - c l e a n i n g tests. O u t of a l o n g l i s t of possible tests t h e f o l l o w i n g six (1) were chosen f o r use i n e x p e r i m e n t a l w o r k : M e t h o d 1. Exploratory " S p r a y R a t i n g " Test (for Repellency E v a l u a t i o n ) . T h e test s p e c i m e n , a 7 X 7 i n c h s q u a r e piece o f t r e a t e d f a b r i c , i s f a s t e n e d s e c u r e l y i n t h e 6 - i n c h m e t a l h o o p , a n d t h e h o o p p l a c e d w i t h the f a b r i c face u p p e r m o s t o n t h e base s t a n d . T h e flow o f w a t e r d o w n t h e f a b r i c m u s t c o i n c i d e w i t h t h e w a r p wise d i r e c t i o n of t h e s a m p l e — i . e . , t h e r i b s o f t h e f a b r i c m u s t b e d i a g o n a l t o t h e flow o f t h e w a t e r r u n n i n g off t h e s a m p l e . T h e n 250 m l . o f w a t e r o f t e m p e r a t u r e 80° ± 1 ° F . i s p o u r e d i n t o the f u n n e l a n d a l l o w e d to s p r a y on t h e f a b r i c . T h e d u r a t i o n of t h e s p r a y is a b o u t 25 t o 30 seconds. A t t h e c o m p l e t i o n o f t h e s p r a y i n g p e r i o d t h e h o o p i s h e l d b y one edge, a n d t h e o p p o s i t e edge t a p p e d a g a i n s t a s o l i d o b j e c t . T h e h o o p i s r o t a t e d 180° a n d t a p p e d once m o r e t o s h a k e off loosely h e l d w a t e r d r o p l e t s . A f t e r t a p p i n g , the s p o t t e d o r w e t t e d p a t t e r n i s c o m p a r e d w i t h s t a n d a r d s . T h e f a b r i c is assigned t h e r a t i n g o f t h e s t a n d a r d t o w h i c h i t m o s t n e a r l y c o r r e s p o n d s . M e t h o d 2 . R a i n Test (for Repellency E v a l u a t i o n ) . T h e standard drop pene t r a t i o n a p p a r a t u s e m p l o y e d i n t h e r a i n test i s s i m i l a r t o t h a t s h o w n i n (1). I n t h e p r o c e d u r e a n 8 X 9 i n c h test s p e c i m e n is p l a c e d i n t h e s a m p l e h o l d e r ; t h e n t h e s a m p l e h o l d e r w i t h the f a b r i c is p l a c e d o n t h e 45° s a m p l e s u p p o r t i n t h e p a t h o f t h e f a l l i n g d r o p s a n d a t i m i n g device i s c o n c u r r e n t l y s t a r t e d . T h e w a t e r passes t h r o u g h t h e fabric, a n d is drained into a graduated cylinder where i t is measured. T h e time r e q u i r e d t o collect 10 m l . of w a t e r i n t h i s m a n n e r is a r e l a t i v e m e a s u r e o f t h e resistance of a g i v e n s p e c i m e n t o the passage o f f a l l i n g d r o p s . A second w a y of d e t e r m i n i n g t h e resistance o f t h e f a b r i c t o f a l l i n g d r o p s i n t h i s m e t h o d i s t o d e t e r m i n e the a m o u n t of w a t e r p a s s i n g t h r o u g h t h e f a b r i c d u r i n g 2 0 m i n u t e s . T h i s l a t t e r p r o c e d u r e is the one e m p l o y e d m o s t o f t e n i n o u r tests. M e t h o d 3 . W a s h Test (for Fastness E v a l u a t i o n ) . A s m a l l " d i a p e r w a s h e r " i s filled w i t h w a t e r a t 1 6 0 ° F . T h e w a s h s o l u t i o n c o n t a i n s 0 . 2 5 % s o a p , 0 . 1 % s o d i u m b i c a r b o n a t e , a n d a l i t t l e s o f t e n i n g a g e n t — f o r e x a m p l e , 0 . 1 % V e r s e n e . T h e test f a b r i c is p l a c e d i n t h e w a s h e r w i t h e n o u g h o t h e r f a b r i c t o m a k e u p t h e l o a d r e c o m m e n d e d b y the m a n u f a c t u r e r (about 2 pounds of c l o t h ) . T h e c l o t h is w a s h e d f o r 15 m i n u t e s , f o l l o w e d b y t h r e e 5 - m i n u t e rinses. T h e f a b r i c is d r i e d i n a n o v e n a t 1 4 0 ° F . a n d i r o n e d . I t is a l l o w e d t o s t a n d o v e r n i g h t , a n d o n t h e f o l l o w i n g d a y t h e f a b r i c is p u t t h r o u g h t h e s p r a y r a t i n g test. M e t h o d 4 . Solvent Extraction Test (for Fastness E v a l u a t i o n ) . I n a 1-pint bottle are p l a c e d 200 m l . of clean S t o d d a r d Solvent and a test piece of fabric 7 inches


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227

s q u a r e . T h e b o t t l e is c a p p e d a n d s h a k e n f o r 30 m i n u t e s o n a s h a k i n g m a c h i n e . T h e c l o t h is r e m o v e d , c e n t r i f u g e d t o r e m o v e excess l i q u i d , a n d d r i e d i n a n o v e n a t 1 4 0 ° F . T h e f a b r i c i s i r o n e d a n d p l a c e d o n a r a c k t o age f o r 2 4 h o u r s . A f t e r t h i s p e r i o d of t i m e a s p r a y r a t i n g test i s r u n o n t h e test f a b r i c . M e t h o d 5 . A i r Permeability Test. A f t e r t h e i n n e r c y l i n d e r has been r a i s e d t o t h e p r o p e r h e i g h t , t h e s a m p l e piece o f f a b r i c i s c l a m p e d s e c u r e l y b e t w e e n t h e orifice p l a t e s . T h e i n n e r c y l i n d e r is released a n d t h e t i m e r e q u i r e d f o r 300 m l . o f a i r t o pass through the cloth is a measure of the air permeability of the fabric. M e t h o d 6 . Practical D r y - C l e a n i n g Tests. C o n f i r m a t o r y p r a c t i c a l tests were m a d e b y c o m m e r c i a l d r y cleaners.


Discussion T h e r e is c o n s i d e r a b l e n e e d i n the t e x t i l e i n d u s t r y t o d a y f o r m a t e r i a l s , e i t h e r d u r a ble o r n o n d u r a b l e , w h i c h can b e a p p l i e d t o c l o t h t o render i t water repellent. These m a t e r i a l s , besides b e i n g effective w a t e r r e p e l l e n t s , s h o u l d be easy t o a p p l y , a n d i n e x p e n s i v e , a n d s h o u l d n o t decrease t h e a i r p e r m e a b i l i t y o r i m p a i r t h e h a n d o f t h e c l o t h . I n g e n e r a l , t h e n o n d u r a b l e r e p e l l e n t s a r e s o l d e i t h e r as n a p h t h a - s o l u b l e c o n c e n t r a t e s t o d r y cleaners, o r as w a t e r - e m u l s i f i a b l e pastes t o t e x t i l e m i l l s . A f e w a r e s o l d i n t h e f o r m o f d i l u t e n a p h t h a s o l u t i o n s i n p r e s s u r e cans, w i t h F r e o n as t h e p r o p e l l a n t , f o r use i n the home. T h e n a p h t h a - s o l u b l e pastes are c o m p o s e d o f a m i x t u r e o f a w a x a n d a n a p h t h a soluble a l u m i n u m salt s u c h as a l u m i n u m stéarate. T h e w a t e r - e m u l s i f i a b l e pastes are aqueous d i s p e r s i o n s c o n t a i n i n g a l u m i n u m acetate o r f o r m a t e , e m u l s i f y i n g agents, a n d p r o t e c t i v e c o l l o i d s i n t h e c o n t i n u o u s phase a n d a b l e n d o f waxes i n t h e d i s p e r s e d p h a s e . S o m e silicone oils are also s o l d f o r use i n n a p h t h a s o l u t i o n s o r w a t e r e m u l s i o n s . N o n d u r a b l e w a t e r r e p e l l e n t s are a p p l i e d t o t h e f a b r i c b y t w o g e n e r a l p r o c e d u r e s : (1) T h e paste e m u l s i f i e d i n w a t e r is a p p l i e d b y p a d d i n g a n d is d r i e d a t a t e m p e r a t u r e a r o u n d 2 5 0 ° F . i n o r d e r t o d e c o m p o s e t h e a l u m i n u m s a l t ; g e n e r a l l y a deposit o f 2 o r 3 % a c t i v e solids i s sufficient t o g i v e s a t i s f a c t o r y r e s u l t s . ( 2 ) T h e n a p h t h a - s o l u b l e pastes are d i l u t e d w i t h s o l v e n t t o o b t a i n t h e d e s i r e d t r e a t i n g s o l u t i o n . T h e f a b r i c i s immersed i n the treating solution w i t h agitation for a short period, removed, a n d cured a t 1 4 0 ° F . o r l o w e r . O n n e w f a b r i c s 2 o r 3 % a c t i v e i n g r e d i e n t s a r e sufficient f o r desirable results. T h e naphtha-soluble water repellents are employed p r i m a r i l y b y the d r y cleaner, a n d t h e d r y cleaner s e l d o m t r e a t s n e w f a b r i c w i t h t h e m . U s u a l l y a d r y - c l e a n e d g a r m e n t c o n t a i n s a m i n u t e f i l m o f s o a p o r d e t e r g e n t o n t h e s u r f a c e . B e c a u s e these are w e t t i n g agents, a n d a c t i n o p p o s i t i o n t o t h e w a t e r r e p e l l e n t , a l a r g e a m o u n t o f w a x m u s t b e p u t o n t h e f a b r i c t o o v e r c o m e t h e i r effect. O f t e n 5 t o 1 0 % solids m u s t b e a p p l i e d t o t h e f a b r i c t o o b t a i n e v e n f a i r r e s u l t s , a n d 15 t o 1 7 % solids t o o b t a i n d e s i r a b l e r e s u l t s . B e c a u s e o f s u c h l i m i t i n g c o n d i t i o n s as t e m p e r a t u r e , costs, a n d e q u i p m e n t , t h e d r y cleaner c a n n o t use d u r a b l e r e p e l l e n t s . A l s o , he c a n n o t e m p l o y w a t e r - e m u l s i o n t y p e o f n o n d u r a b l e r e p e l l e n t s f o r fear t h a t excessive s h r i n k a g e o f g a r m e n t s m i g h t o c c u r d u r i n g t h e t r e a t i n g process. T h e o n l y p r o d u c t s a v a i l a b l e t o t h e d r y cleaner a r e o f t e n t h e n a p h t h a - s o l u b l e n o n d u r a b l e pastes. T h e m a t e r i a l s s t u d i e d i n t h i s i n v e s t i g a t i o n are silane d e r i v a t i v e s o r l o w o r d e r s i l i cones. B e c a u s e t h e y c o n t a i n l o n g a l k y l h y d r o c a r b o n c h a i n s t h e y a r e , i n a sense, a h y b r i d of a w a x a n d a silicone, b o t h of w h i c h are k n o w n t o have h y d r o p h o b i c o r w a t e r r e p e l l e n t p r o p e r t i e s . B y c o m b i n i n g t h e m i n t h e same m o l e c u l e i t w a s h o p e d t o p r o d u c e substances m o r e r e p e l l e n t t h a n e i t h e r p a r e n t s u b s t a n c e , a n d c h e a p e r t h a n t h e p u r e silicones. B y h a v i n g e a s i l y h y d r o l y z a b l e h y d r o g e n o r m e t h o x y g r o u p s o n t h e s i l i c o n nucleus, i t was hoped t o achieve c u r i n g of the water repellent o n the fabric a t r o o m t e m p e r a t u r e . M a n y classes o f silane d e r i v a t i v e s were s y n t h e s i z e d a n d t e s t e d , i n t h e quest f o r m a t e r i a l s w h i c h w o u l d p r o v e effective w h e n u s e d i n l o w c o n c e n t r a t i o n s . A l k y l c h a i n s c o n t a i n i n g m o r e t h a n 12 c a r b o n a t o m s were f o u n d t o be necessary, p r e f e r -


228


a b l y 16 t o 18. T w o s u c h a l k y l g r o u p s w o r k e d b e t t e r t h a n one o r t h r e e . or u n s a t u r a t i o n i n this carbon c h a i n was deleterious.

Branching

Results Exploratory Spray Rating Tests. T h e effect o n s e v e r a l t y p e s o f c l o t h o f d i s t e a r y l methoxysilane repellent, i n comparison w i t h various textile water-repellent composi t i o n s used c o m m e r c i a l l y b y t h e d r y - c l e a n i n g i n d u s t r y , is s h o w n i n T a b l e I . T h e s e


Table I.

Repellents A Β C D Ε F G H Formula II β 6

Spray Rating Tests on Commercial Water-Repellent

Concn.° 1:9 1:3 1:8 1 : 10 1:8 100% 1:7 1:5

Khaki Oxford (New) 90 100 90 50 90 50 70 90 100

Raincoat Formula

Compositions

6

Charged System Khaki Poplin 0 80 0 0 0 0 0 0 90 6

Khaki Oxford 70 90 50 0 70 0 70 70 100

Khaki poplin 80 90 70 0 70 0 70 70 100

Brown poplin 100 100 100 100 90 70 100 100 100

Rayon wool 80 80 70 80 70 50 90 80 100

Rayon gabardine 90 90 80 80 50 50 90 100 100

Recommended by manufacturer. See text.

r e s u l t s h a v e o n l y q u a l i t a t i v e significance. T h e t r e a t i n g s o l u t i o n s were p r e p a r e d b y t h e m e t h o d s p r e s c r i b e d b y t h e m a n u f a c t u r e r s . T h e f a b r i c s were a d d e d t o t h e t r e a t i n g s o l u t i o n s a t t h e r a t e o f 3 0 p o u n d s o f f a b r i c p e r 100 p o u n d s o f s o l u t i o n a n d w e r e i m m e r s e d f o r 5 m i n u t e s . T h e f a b r i c w a s r e m o v e d a n d e x t r a c t e d u n t i l t h e w e i g h t increase w a s 15 t o 2 0 % o f t h e w e i g h t o f t h e f a b r i c ; t h i s r e q u i r e d a b o u t 12 seconds. A f t e r e x t r a c t i o n t h e fabric was t u m b l e d f o r 3 0 minutes a t 140°F. T h e fabric w a s pressed a n d h u n g i n a n atmosphere k e p t a t 70°F. a n d 6 5 % relative h u m i d i t y f o r 24 hours before testing. I n t h i s easy test, r a t i n g s o f 9 0 o r 100 a r e t o b e c o n s i d e r e d g o o d , 8 0 i s f a i r , a n d 7 0 o r b e l o w is p o o r . T a b l e I s h o w s t h a t m a n y r e p e l l e n t s p e r f o r m r e a s o n a b l y w e l l o n n e w c l o t h . T h e y w o r k b e t t e r o n some t y p e s o f c l o t h t h a n o n o t h e r s a n d t h e y a r e g e n e r a l l y less effective o n c l o t h w h i c h has b e e n d r y - c l e a n e d a n d w h i c h c o n t a i n s r e s i d u a l traces o f d r y - c l e a n i n g soaps. D i f f e r e n t d r y - c l e a n i n g m e t h o d s l e a v e b e h i n d different a m o u n t s o r t y p e s o f s u c h s o a p s . N o o n e c o m m e r c i a l r e p e l l e n t is s a t i s f a c t o r y o n a l l t y p e s o f c l o t h . F o r m u l a I I h a s g i v e n u n i f o r m l y excellent results i n t h i s t e s t ; 100 r a t i n g s a r e o b t a i n e d w i t h s u c h v a r i e d t y p e s o f f a b r i c as c o t t o n s h i r t i n g 3.65, c o t t o n p o p l i n 5.90, w i n d r e s i s t a n t c o t t o n p o p l i n 6.75, I n d i a n H e a d c o t t o n 4.85, w i n d - r e s i s t a n t c o t t o n O x f o r d 9.00, D y n e l 8.08, l i n e n 3.30, l i n e n 6.50, n y l o n 3.20, r a y o n 4.55, r a y o n - g a b a r d i n e 6.75, 60 t o 4 0 r a y o n w o o l 10.90, s i l k 1.98, a n d p a n t s f a b r i c w o o l 6.64. T h e n u m b e r s a b o v e refer t o w e i g h t s o f f a b r i c i n ounces p e r r u n n i n g y a r d o f y a r d - w i d e m a t e r i a l . T h e s t a n d a r d m e t h o d s u s e d f o r d r y - c l e a n i n g t h e f a b r i c s m e r i t some d e s c r i p t i o n . I n t h e raincoat f o r m u l a , a n emulsion consisting of 1 p a r t of C y c l o Soap ( d r y - c l e a n i n g soap supplied b y R . R . Street a n d C o . ) , 1 p a r t of S t o d d a r d Solvent, a n d 1 p a r t of w a t e r w a s a d d e d a t t h e r a t e o f 3 ounces f o r e a c h p o u n d o f f a b r i c , a n d 1 g a l l o n o f Stoddard Solvent. T h e n Buckeye paint remover (manufactured b y Davies Y o u n g S o a p C o . ) i s a d d e d a t t h e r a t e o f 0.6 o u n c e p e r p o u n d o f f a b r i c t o b e c l e a n e d . T h e fabric is added, a n d the load is r u n for 20 minutes, after w h i c h the solvent is drained f r o m t h e machine. T h e machine is filled w i t h fresh solvent a n d t h e l o a d rinsed f o r 20 m i n u t e s . T h e f a b r i c is e x t r a c t e d a n d is t u m b l e d a t 1 4 0 ° F . f o r 30 m i n u t e s t o r e m o v e t h e l a s t traces o f s o l v e n t . I n the charged system, the washer containing S t o d d a r d Solvent is charged w i t h 0 . 7 5 % b y v o l u m e o f a s y n t h e t i c d e t e r g e n t (886 s o l d b y R , R . S t r e e t a n d C o . ) . T h e f a b r i c is a d d e d a t t h e r a t e o f 1 p o u n d of f a b r i c p e r p o u n d o f s o l v e n t , a n d t h e n 1 o u n c e of w a t e r p e r p o u n d o f f a b r i c i s a d d e d . T h e m a c h i n e i s r u n f o r 3 0 m i n u t e s , e m p l o y i n g



229

c o n s t a n t f i l t r a t i o n . A t t h e e n d o f t h e filtration c y c l e the w a s h e r i s d r a i n e d a n d refilled w i t h f r e s h s o l v e n t . T h e l o a d is r i n s e d f o r 10 m i n u t e s a n d e x t r a c t e d . A f t e r e x t r a c t i o n t h e f a b r i c is t u m b l e d a t 1 4 0 ° F . for 30 m i n u t e s .


R a i n T e s t s . A m o r e d i f f i c u l t test f o r a w a t e r r e p e l l e n t t o pass i s the r a i n test. H e r e w a t e r d r o p l e t s f a l l o n t o t h e t r e a t e d c l o t h f r o m a h e i g h t o f 3 t o 10 feet, d e p e n d i n g o n t h e t y p e o f c l o t h u s e d , a n d the a m o u n t o f w a t e r i s m e a s u r e d w h i c h passes t h r o u g h the cloth i n a given length of time. M a n y repellents exhibit good s p r a y ratings, b u t s h o w u p v e r y p o o r l y i n t h e r a i n test. F i g u r e s 1 a n d 2 s h o w t h e results o b t a i n e d w i t h

Time,Minutes Figure 1. Rain test Fabric. 60 to 40 rayon-wool Head of water. 5 feet

Fabric. 7-ounce, cotton Oxford (dry cleaned) Head of water. 5 feet


230


a n e w 6 0 t o 4 0 r a y o n - w o o l a n d a d r y - c l e a n e d c o t t o n O x f o r d (7 o u n c e ) f a b r i c , b o t h u n d e r a 5-foot h e a d o f w a t e r . A s i d e f r o m F o r m u l a I I , t h e p r o d u c t s t e s t e d a r e p r o b a b l y t h e largest s e l l i n g n o n d u r a b l e r e p e l l e n t s u s e d b y t h e d r y - c l e a n i n g i n d u s t r y . A i r Permeability Tests. I t is n o t d i f f i c u l t t o t r e a t f a b r i c so t h a t i t sheds w a t e r , e v e n i n a r a i n test a p p a r a t u s , i f t h e p o r e s i n t h e f a b r i c a r e c l o g g e d . I n e v a l u a t i n g w a t e r - r e p e l l e n t c o m p o s i t i o n s , i t is, t h e r e f o r e , i m p o r t a n t t o m e a s u r e t h e i r a i r p e r m e a b i l i t y a f t e r t h e w a t e r - r e p e l l e n c y t r e a t m e n t h a s b e e n a p p l i e d t o t h e c l o t h . T h e results o f tests o n c o t t o n O x f o r d c l o t h a r e s h o w n i n T a b l e I I . N o n e o f t h e p r o d u c t s clogs t h e


Table II.

A i r Permeability of 7-Ounce Khaki O x f o r d Fabric

Repellent Used None A Β C Ε J Κ Formula I I

Time to Pass 300 M l . of Air, Sec. 26 26 28 29 29 54 31 28

Reduction, % — 0 8 12 12 107 20 8

p o r e s excessively e x c e p t p r o d u c t J , a n d p o s s i b l y p r o d u c t K . s i m i l a r results i n t h i s t e s t .

Other types of cloth give

Fastness Tests. T h e d u r a b i l i t y o f r e p e l l e n t - t r e a t e d f a b r i c s a m p l e s w a s t e s t e d b y s u b j e c t i n g t h e m t o w a s h tests d e s c r i b e d i n M e t h o d 3 . A t t e m p t s w e r e m a d e t o r e m o v e t h e w a t e r - r e p e l l e n t f i l m s b y w a s h i n g w i t h S t o d d a r d S o l v e n t as w e l l as w i t h s o a p a n d w a t e r . S p r a y r a t i n g s were d e t e r m i n e d o n t h e f a b r i c s a m p l e s b o t h b e f o r e a n d a f t e r t h e washings.

Table

Repellent Treatment Β Formula I I Zelan

Effect of Washing a n d Dry Cleaning of Treated Fabrics Spray Rating Values Treated cloth 100 100 100

After wash 50 50 100

After dry cleaning 70 70 100

Zelan is a water repellent of t h e durable t y p e ; F o r m u l a I I is a repellent of the nondurable type. Practical D r y - C l e a n e r Tests. I n o r d e r t o get experience w i t h c o m m e r c i a l p r a c t i c e , samples of repellent treatments f r o m various d r y - c l e a n i n g establishments i n t h e C l e v e l a n d , Ohio, area were secured. R a y o n g a b a r d i n e f a b r i c w a s o b t a i n e d , w h i c h , as s h o w n i n T a b l e I , c o l u m n 8, is a n easy m a t e r i a l t o m a k e w a t e r r e p e l l e n t . S e v e r a l y a r d l e n g t h s of t h i s c l o t h were sent t o e a c h o f s e v e r a l cleaners w i t h i n s t r u c t i o n s t o c l e a n a n d t r e a t

Table IV. WaterRepellent Product Tested Formula I I A Β C G α

Commercial Treatments in the Cleveland A r e a Cloth Cleaned and Treated by Authors (Raincoat Formula) 100 90 90 80 90

Cloth Cleaned and Treated by Local Dry Cleaners* 80, 100 80, 80 90. 0

Cleaned by Outside Cleaner, Treated by Authors Charged system 100 80 90 80 70

Raincoat formula 100 90 90 80 90

Results from two different cleaners.

t h e m as d e s c r i b e d i n T a b l e I V . ( O n l y those cleaners p a r t i c i p a t e d w h o disclosed t h e p a r t i c u l a r w a t e r - r e p e l l e n t p r o d u c t s used.) O n receipt of t h e treated cloths, s p r a y r a t -


231


i n g tests were m a d e . C o l u m n 3 shows t h a t t h e w a t e r - r e p e l l e n t t r e a t m e n t b e i n g s o l d b y s o m e d r y cleaners is n o t v e r y effective, p a r t i c u l a r l y w h e n i t is r e m e m b e r e d t h a t t h i s i s a n easy f a b r i c t o t r e a t . T h e zero r e s u l t i n c o l u m n 3 suggests t h a t t h e cleaner c l e a n e d the cloth, b u t d i d not give i t the water-repellent treatment. F u r t h e r p r a c t i c a l a p p l i c a t i o n tests h a v e been m a d e b y a r r a n g e m e n t s w i t h a d r y cleaner, t o t r e a t 5 0 - p o u n d b a t c h e s o f v a r i o u s f a b r i c s a f t e r c l e a n i n g t h e m b y e i t h e r t h e raincoat f o r m u l a o r the more widely used charged system. T h e water repellency of these m a t e r i a l s w a s t h e n t e s t e d i n t h e l a b o r a t o r y . T h e r e p e l l e n c y v a l u e s h a v e been u n i f o r m l y h i g h e r t h a n those g i v e n b y c o m m e r c i a l n o n d u r a b l e r e p e l l e n t s , a n d t h e h a n d of t h e t r e a t e d f a b r i c was g o o d .


Preparation of Distearyl

Methoxysilane

I n a 1 2 - l i t e r flask, f i t t e d w i t h a s t i r r e r , a gas i n l e t t u b e w h i c h reaches n e a r l y t o t h e b o t t o m o f t h e flask, a n d a r e f l u x c o n d e n s e r , i s p l a c e d 5000 g r a m s (18.5 m o l e s ) o f o c t a d e c y l a l c o h o l . A t h e r m o m e t e r i s s u s p e n d e d i n s i d e t h e condenser so t h a t t h e b u l b is b e l o w t h e s u r f a c e of t h e a l c o h o l . T h e a l c o h o l is h e a t e d t o 1 0 0 ° C , a n d d r y h y d r o g e n b r o m i d e i s passed i n a t 100° t o 1 2 0 ° C . u n t i l n o m o r e a b s o r p t i o n o c c u r s ( a b o u t 2 hours). T h e crude octadecyl bromide product is transferred t o a separatory funnel, s e p a r a t e d f r o m t h e aqueous h y d r o b r o m i c a c i d f o r m e d d u r i n g t h e r e a c t i o n , a n d s h a k e n w i t h one t h i r d i t s v o l u m e o f c o n c e n t r a t e d s u l f u r i c a c i d t o r e m o v e t h e u n r e a c t e d a l c o h o l . T h e l o w e r a c i d l a y e r i s d r a w n off a n d d i s c a r d e d . T h e r e s i d u a l b r o m i d e i s m i x e d w i t h a n e q u a l v o l u m e o f 9 0 % m e t h a n o l a n d aqueous a m m o n i a i s a d d e d w i t h i n t e r m i t t e n t shaking until the solution is alkaline t o phenolphthalein. T h e lower bromide layer is d r a w n off a n d w a s h e d once w i t h 9 0 % m e t h a n o l . I t is t h e n d r i e d w i t h c a l c i u m c h l o r i d e , f i l t e r e d , a n d d i s t i l l e d . T h e y i e l d o f t h e o c t a d e c y l b r o m i d e p r o d u c t , b o i l i n g a t 213° t o 2 1 6 ° C . / 1 4 m m . m e r c u r y , i s 5360 g r a m s ( 8 7 % of t h e o r y ) . I n a 5 - l i t e r , 3 - n e c k e d flask f i t t e d w i t h a s t i r r e r , s e p a r a t o r y f u n n e l , a n d a condenser e q u i p p e d w i t h a c a l c i u m c h l o r i d e t u b e , is p l a c e d 100 g r a m s o f m a g n e s i u m t u r n i n g s . A s m a l l c r y s t a l o f i o d i n e a n d a b o u t 100 m l . o f a n h y d r o u s e t h e r a r e a d d e d . T h e n 100 m l . of a m i x t u r e o f 1330 g r a m s ( 4 m o l e s ) o f n - o c t a d e c y l b r o m i d e a n d 2 l i t e r s o f d r y e t h e r is a d d e d . Localized heating m a y be a p p l i e d t o start the reaction, i f desired, a n d after i t h a s s t a r t e d , the rest o f t h e b r o m i d e - e t h e r m i x t u r e i s a d d e d o v e r a p e r i o d o f 1 t o 2 hours, as determined b y the rate of reflux. A f t e r complete a d d i t i o n , the m i x t u r e i s r e f l u x e d f o r a n o t h e r h o u r t o ensure c o m p l e t i o n o f t h e r e a c t i o n . F i n a l l y , i t i s d i l u t e d w i t h a n a d d i t i o n a l 2 l i t e r s o f a n h y d r o u s e t h e r f o r use i n t h e n e x t s t e p . I n a 6 - l i t e r , 3 - n e c k e d flask e q u i p p e d w i t h a d r o p p i n g f u n n e l , m e r c u r y - s e a l e d s t i r r e r , a n d a reflux condenser e q u i p p e d w i t h a c a l c i u m c h l o r i d e t u b e , are p l a c e d 67.7 g r a m s (0.5 m o l e ) o f t r i c h l o r o s i l a n e a n d 2 l i t e r s o f d r y b e n z e n e . Stirring is commenced. T h r o u g h t h e d r o p p i n g f u n n e l is a d d e d 312.5 g r a m s ( 1 m o l e ) o f n - o c t a d e c y l m a g n e s i u m dissolved i n a liter of ether—i.e., the p r o d u c t f r o m the foregoing p a r a g r a p h . T h i s a d d i t i o n is m a d e o v e r a p e r i o d o f 2 h o u r s , a t a t e m p e r a t u r e b e l o w 3 0 ° C . T h e contents of t h e flask are s t i r r e d f o r a n a d d i t i o n a l h o u r t o c o m p l e t e t h e r e a c t i o n . T h e n 4 8 g r a m s (1.5 m o l e s ) o f m e t h a n o l i s a d d e d d r o p wise so as n o t t o l e t t h e t e m p e r a t u r e rise a b o v e 3 0 ° C , w h i c h r e q u i r e s a n a d d i t i o n a l 2 h o u r s . T h e n t h e flask i s h e a t e d t o 70° t o 8 0 ° C , w h i l e a s t r e a m o f d r y n i t r o g e n i s passed o v e r t h e s u r f a c e . H e a t i n g a n d s t i r r i n g are c o n t i n u e d u n t i l e v o l u t i o n o f h y d r o g e n c h l o r i d e ceases; t h i s r e q u i r e s a b o u t 6 h o u r s . T h e c o n t e n t s o f t h e flask are t h e n c o o l e d a n d f i l t e r e d . T h e filter c a k e i s w a s h e d t w i c e w i t h t w o 5 0 - m l . p o r t i o n s o f d r y benzene. T h e filtrate is fractionated a t atmospheric p r e s s u r e t o r e m o v e t h e benzene, m e t h a n o l , a n d r e s i d u a l e t h e r . A n o i l y f r a c t i o n w h i c h d i s t i l l s a t 160° t o 2 2 5 ° C . / 3 m m . i s r e m o v e d a n d d i s c a r d e d . T h e p r o d u c t , a n a m b e r c o l o r e d l i q u i d a t e l e v a t e d t e m p e r a t u r e s , i s p o u r e d i n t o a flask, s t o p p e r e d , a n d a l l o w e d t o c o o l . A t r o o m t e m p e r a t u r e i t is a w h i t e s o l i d m e l t i n g a t 6 5 - 6 7 ° C . Carbon Hydrogen Silicon

Found on Analysis, % 77.3 13.5 5.8

Calculated for (ΟηΆι&ϊΟ) ,% 78.4 13.5 5.1 χ

T h e m o l e c u l a r w e i g h t b y e b u l l i o m e t r y w a s 1 1 2 0 , so t h a t , i n t h e f o r m u l a ( C H S i O ) . , t h e v a l u e o f χ i s 2.0, i n d i c a t i n g s l i g h t p o l y m e r i z a t i o n . 3 e

7 4

a


232


Literature Cited (1) Federal Standard Stock Catalog, Supt. Documents, Washington 25, D. C., Section IV, Part 5, CCC-T-191a. pp. 8, 12, 22, 23, 24, supplement, Oct. 8, 1945.


RECEIVED for review May 10, 1957. Accepted June 1, 1957.


Alkyl Methoxysilane Water Repellents - Advances in Chemistry (ACS

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