Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1997-08-14
1999-08-10
Merriam, Andrew E. C.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524792, 525397, 525425, C08G 6532, C08G 8100
Patent
active
059360305
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to polyoxyalkylene block copolymers and a process for their preparation.
BACKGROUND OF THE INVENTION
Dihydroxy terminated triblock copolymer surfactants are known having the general structure H-(E).sub.a (P).sub.b (E).sub.a -OH wherein E represents oxyethylene and P represents oxypropylene. Such nonionic surfactants are commercially available e.g. Pluronic.TM. surfactants.
U.S. Pat. No. 4,072,704 describes the preparation of polyoxyalkylene block copolymer surfactants by reacting individual blocks of polymers and copolymers of alkylene oxides with formaldehyde or a dialkyl carbonate. For example, the surfactants can contain polyoxyethylene and polyoxypropylene polymers linked by formal or carbonate groups.
PROBLEM TO BE SOLVED BY THE INVENTION
Alternative polyoxyalkylene block copolymers and a process for their production are required. In particular, a simpler process of preparation which makes it possible to prepare copolymers of higher molecular weight is desired.
SUMMARY OF THE INVENTION
The invention provides a block copolymer containing one or more polyoxyethylene blocks and one or more polyoxy(higher alkylene) blocks wherein at least some of the blocks are linked together by a linking group characterised in that the linking group is an oxymethylene group.
The invention also provides a process for preparing a block copolymer containing one or more polyoxyethylene blocks and one or more polyoxy(higher alkylene) blocks characterised in that one or more dihydroxy terminated polymers selected from poly(ethylene glycol), poly(higher alkylene glycol) and block copolymers thereof are reacted in solution with a dihalomethane in the presence of a base.
ADVANTAGEOUS EFFECT OF THE INVENTION
The reaction can be carried out using an excess of the dihalomethane as a solvent for the other reactants. Heating is not required as the reaction proceeds at ambient temperature.
Polyoxyalkylene block copolymers can be prepared having a higher molecular weight than those prepared using other processes.
The methylene oxide linking groups closely resemble the chemical structure of the other groups forming the polymer blocks.
DETAILED DESCRIPTION OF THE INVENTION
Preferred copolymers of the invention include those wherein the polyoxy(higher alkylene) blocks are selected from polyoxypropylene and polyoxybutylene blocks.
In one embodiment of the invention, block copolymers are provided having the following repeating units in random order
In another embodiment of the invention, block copolymers are provided having the following repeating units
The molecular weight of a block copolymer of the invention as measured by gel permeation chromatography against poly(oxyethylene) standards may range from 10,000 to 500,000, preferably from 50,000 to 250,000.
The polymers can be prepared by a process wherein one or more dihydroxy terminated polymers selected from poly(ethylene glycol), poly(higher alkylene glycol) and block copolymers thereof are reacted in solution with a dihalomethane in the presence of a base.
Examples of suitable solvents in which the reagents can be dissolved include dihalomethanes and other known organic solvents such as benzene, chlorobenzene and toluene or mixtures thereof.
Preferably, an excess of the dihalomethane reagent is used as the solvent. Even though the dihalomethane is used in an amount which can far exceed the stoichiometric amount needed to couple with the polymeric reactants, products of high molecular weight can still be achieved.
Although any dihalomethane or mixture thereof may be used such as dichloromethane, dibromomethane or diiodomethane, the preferred dihalomethane is dichloromethane.
The required alkaline reaction conditions may be obtained by incorporating one or more bases such as sodium hydroxide and potassium hydroxide.
Examples of the dihydroxy terminated polymer starting materials include the polyethylene glycols (PEGs) and the polypropylene glycols (PPGs) which are available commercially. Specific examples include PEG 400, PEG
Nicholas Christian Vaughan
Purbrick Malcolm Donald
Merriam Andrew E. C.
Nanosystems
LandOfFree
Polyether copolymers and a process for preparing them does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polyether copolymers and a process for preparing them, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polyether copolymers and a process for preparing them will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1120894