Focus
Patent Summaries T h i s is a l i s t of r e c e n t l y p u b l i s h e d patents covering designs and i n v e n t i o n s of r e l e v a n c e to synthetic membrane technology. Where the same device has been patented in several countries, we n o r m a l l y give t h e B r i t i s h p a t e n t n u m b e r . If t h e r e is n o UK p a t e n t , we give t h e n u m b e r of a n E n g l i s h l a n g u a g e p a t e n t , if o n e e x i s t s . The p a t e n t s list is c o m p i l e d from i n t e r n a t i o n a l s o u r c e s b y B H R G r o u p ' s i n f o r m a t i o n service. T h e facility c a n also b e u s e d to c a r r y out retrospective patent searches - - to t e s t t h e validity, n o v e l t y or i n f r i n g e m e n t of e x i s t i n g p a t e n t s or n e w i d e a s . B H R G r o u p , Cranfield, Bedford MK43OAJ, UK, will provide free e s t i m a t e s o n r e q u e s t . Countries can be identified by t h e c o d e in f r o n t of t h e n u m b e r a s follows: AT Austria BE Belgium CH Switzerland DE West Germany EP European Patents FI Finland GB Britain IL Israel IT Italy KP North Korea LU Luxembourg NO Norway RU Russia SE Sweden SU Soviet Union Cooperation
AU Australia BR Brazil DD East Germany DK Denmark ES Spain FR France HU Hungary IR Eire JP J a p a n LI Liechtenstein NL Netherlands RO Romania US United States WO World Patent (Patent Treaty publication)
BHR G r o u p d o e s n o t o p e r a t e a d o c u m e n t delivery service for p a t e n t s , b u t full c o p i e s of t h e original p a t e n t d o c u m e n t s c a n b e o b t a i n e d from t h e following addresses: The British Library Patent Express 25 S o u t h a m p t o n B u i l d i n g s L o n d o n W C 2 A lAW, UK Fax: 0171 323 7 2 3 0 (The B r i t i s h L i b r a r y will also s u p p l y a list of UK l i b r a r i e s i n c l u d e d in t h e P a t e n t I n f o r m a t i o n Network.) US P a t e n t Office Scientific L i b r a r y
M e m b r a n e T e c h n o l o g y No. 9 3
15th a n d E a s t S t r e e t s , NW W a s h i n g t o n , DC 2 0 2 3 1 , USA
Oxidising treatment for composite membrane A n o x i d i s a t i o n s t e p in t h e p r o c e s s allows t h i s r e v e r s e o s m o s i s m e m b r a n e to b e o p e r a t e d a t t h e r e l a t i v e l y low p r e s s u r e of 3 k g / c m 2 a n d still give a c c e p t a b l e flux a n d s a l t r e j e c t i o n v a l u e s . T h e m e m b r a n e ' s s e p a r a t i o n l a y e r is a p o l y a m i d e s y n t h e s i s e d from a r a n g e of b i f u n c t i o n a l a m i n o c o m p o u n d s a n d a r a n g e of polyfunctional acid halides. The o x i d i s i n g a g e n t is chlorine, in t h e f o r m of free c h l o r i n e in a s o d i u m hypochlorite solution, and the r a t e of r e a c t i o n c a n b e c a t a l y s e d b y m e t a l i o n s in s o l u t i o n . T h e o t h e r c o m p o n e n t of t h e c o m p o s i t e m e m b r a n e is f o r m e d w h e n a n alcohol, ether, k e t o n e , e s t e r or halogenated hydrocarbon, coated o n t h e p o r o u s s u p p o r t of t h e m e m b r a n e in s o l u t i o n w i t h t h e b i f u n c t i o n a l a m i n e , is e n t r a i n e d in t h e p o l y m e r i s a t i o n p r o c e s s . T h e a l c o h o l or e t h e r a l s o h a s a s i g n i f i c a n t effect on t h e flux r a t e of t h e m e m b r a n e , a c c o r d i n g to c o m p a r a t i v e e x a m p l e s given in t h e patent.
Patent number: EP 7 8 7 5 2 5 Date: 6 t h A u g u s t 1997 Inventors: M. Hirose, T. O h a r a , M. Ando Applicant: Nitto D e n k o Corp.
Biopolymer membrane T h e u s e of a b i o p o l y m e r a s t h e s e p a r a t i o n l a y e r of a c o m p o s i t e m e m b r a n e is c l a i m e d in t h i s p a t e n t ; t h e biopolymer, in solution, is c i r c u l a t e d t a n g e n t i a l l y to t h e s u r f a c e of a p o r o u s c e r a m i c wall to p r o d u c e a l a y e r of d e p o s i t e d m a c r o m o l e c u l e s . This is t h e n d r i e d or t a n n e d in o r d e r to give a c o h e r e n t s e p a r a t i o n layer. T h e
m e m b r a n e s a r e h e l d to b e u s e f u l in s i m p l e s e p a r a t i o n s s u c h a s nanofiltration or gas separations, a n d in u l t r a f i l t r a t i o n w h e r e t h e y operate using a simple steric e x c l u s i o n effect. T h e y c a n also b e u s e d for e n z y m a t i c r e a c t i o n s . G e l a t i n is o n e m a t e r i a l r e f e r r e d to in t h e p a t e n t , a n d a n a q u e o u s s o l u t i o n c o n t a i n i n g 10 g / l g e l a t i n w a s u s e d to coat, u n d e r p r e s s u r e , an alumina tube. Formaldehyde s o l u t i o n w a s t h e n u s e d to h a r d e n t h e gelatin, w h i c h w a s a f t e r w a r d s d r i e d a t 110°C. T h e r e s u l t i n g membrane had an average pore size of 2 n m . O t h e r e x a m p l e s r e f e r to s u c c e s s f u l s e p a r a t i o n t e s t s u s i n g p o l y e t h y l e n e glycols of molecular weights 600-6000.
Patent number: W O 9 7 2 9 8 3 9 Date: 2 1 s t A u g u s t 1997 Inventors: G.M. Rios, J.L. Cuq, J.-L. Negrel Applicant: C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e (CNRS)
Composite nanoffltration membrane T h e s u b s t r a t e is a k n o w n m a t e r i a l , t h e active l a y e r is a c r o s s - l i n k e d cellulose h y d r o x y a l k y l e t h e r polymer. T h e m o d i f i e d c e l l u l o s e is c o a t e d on t h e s u b s t r a t e a s a n a q u e o u s s o l u t i o n w h i c h is t h e n r e a c t e d w i t h a n a l d e h y d e to f o r m acetal crosslinking groups. The r e s u l t i n g m e m b r a n e is hydrophilic, resists degradation by h e a t , a n d is s t a b l e in o r g a n i c solvents. In o n e e x a m p l e , a polyetherimide base material was coated with an aqueous solution c o n t a i n i n g 0.1 w t % hydroxypropylcellulose, which was crosslinked with glutaraldehyde at 70°C for 120 m i n s . T h e r e s u l t i n g membrane has a molecular-weight cutoff of 525---620 w h e n u s e d to filter s o l u t i o n s in a r a n g e of organic solvents.
Patent number: W O 9 7 2 0 6 2 2 Date: 1 2 t h J u n e 1997 Inventors: M. S c h m i d t , K.-V. Peinemann Applicant: GKSS -Forschungszentrum Geesthacht GmbH
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