Process for the production of polyether block copolysulfones

Details Process for the production of polyether block copolysulfones Process for the production of polyether block copolysulfones

2000-02-10

2002-04-02

Buttner, David J. (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

C525S534000, C525S535000, C528S171000, C528S174000, C528S391000

Reexamination Certificate

active

06365678

ABSTRACT:

Polyether block copolysulfones (referred to below as PEBSUs) of different structures and produced by different processes are known (e.g., EP-A 739,925, EP-A 781,795, U.S. Pat. No. 5,700,902, U.S. Pat. No. 5,798,437, U.S. Pat. No. 5,834,583 and Macromolecules 1996, 29 (23) 7619-7621). They are valuable materials, e.g., for biomedical applications with great potential for use in dialysis membranes, catheters or blood tubes, etc.
The processes described in the above-mentioned prior art build up the polyether block copolysulfones from the monomer units.
The processes of the prior art have the disadvantage that they can only be implemented economically with the special equipment tailored to polysulfone production and in the large tonnages conventional for industrial thermoplastics (about 1000 tonnes per annum). The special applications of PEBSUs in the field of medical technology, however, mean that it has to be possible to produce economically a range of smaller products in different grades. Thus, there is a technical need for a process for the production of PEBSUs which is economical even in small quantities, is highly variable referring to the composition of educts and at the same time very simple. This process should furthermore be undemanding in terms of equipment, in order to create the preconditions for economic production for products with applications in the medical field.
Surprisingly, it has been found that PEBSUs can be produced from unmodified sulfone polymers by subsequent reaction (transetherification) with hydroxyfunctional poly-ethers. The term “sulfone polymers” here denotes all aromatic sulfone polymers including the group of the actual polysulfones (PSU), polyether sulfones (PES) and polyaryl ether sulfones (PAES).
The present invention therefore provides a process for the production of polyether block copolysulfones, characterized in that an aromatic sulfone polymer (A) is reacted with an aliphatic polyether with at least one, preferably at least two, terminal OH functions (B).
A process in which the components (A) and (B) are reacted in the presence of a basic catalyst (C) is preferred.
The reaction is preferably carried out in a dipolar aprotic solvent (D).
Preferred sulfone polymers (A) are aromatic sulfone polymers with the repeating unit (I)
—E—Ar
1
—SO
2
—Ar
2
—  (I)
wherein
E is a divalent diphenolate radical and
Ar
1
and Ar
2
signify the same or different difunctional aromatic radicals with 6 to 50, preferably 6 to 25, carbon atoms,
Ar
1
and Ar
2
preferably denote, independently of one another, an aromatic radical with 6 to 10 carbon atoms, optionally mono- or polysubstituted by C
1
-C
12
alkyl, and
E preferably denotes a radical of the formula (II)
wherein
R
1
each independently of the other, being the same or different, denotes hydrogen, halogen, C
1
-C
6
alkyl or C
1
-C
6
alkoxy, preferably hydrogen, fluorine, chlorine, bromine,
n denotes an integer from 1 to 4, preferably 1, 2 or 3, especially 1 or 2,
X denotes a chemical bond, —CO—, —O—, —S—, —SO
2
—, alkylene, preferably C
1
-C
8
alkylene, alkylidene, preferably C
2
-C
10
alkylidene, or cycloalkylene, the last 3 radicals mentioned optionally being substituted by substituents selected from halogen, especially fluorine, chlorine, bromine, optionally by fluorine-, chlorine-, bromine-, C
1
-C
4
alkyl- and/or C
1
-C
4
alkoxy-substituted phenyl or naphthyl, and cycloalkylene optionally also being substituted by C
1
-C
6
alkyl.
Where X denotes cycloalkylene, X preferably denotes a radical of the formula (III)
wherein
Y denotes carbon,
R
2
and R
3
, selectable individually for each Y, independently of one another denote hydrogen or C
1
-C
6
alkyl, particularly preferably hydrogen or C
1
-C
4
alkyl, especially hydrogen, methyl or ethyl and
m denotes an integer from 3 to 12, preferably 4 to 8, especially 4 or 5.
Ar
1
and Ar
2
especially denote, independently of one another, phenyl or naphthyl optionally substituted by C
1
-C
4
alkyl, e.g., methyl.
Particularly preferred sulfone polymers are, e.g., the polysulfone of bisphenol A (commercially available with the name of Udel™ from Amoco, Chicago, USA or Ultrason® S from BASF), a polyether sulfone with the idealized structure —(O—C
6
H
4
—SO
2
—C
6
H
4
—)
x
(commercially available, e.g., with the name of Ultrason E from BASF and SumikaExcel from Sumitomo, Japan), the polyaryl ether sulfone with 4,4′-dihydroxydiphenyl structures from Amoco (Radel R), or polysulfones with TMC-bisphenol structures according to DE-OS 3.833.385. All the above types of sulfone polymer can optionally be used in different grades, as regards molecular weight. The choice will be determined by the desired molecular weights of the end products. In general, the sulfone polymers have average molecular weights (weight average) of 5000 to 100,000, preferably 5000 to 75,000, measured by gel permeation chromatog- raphy (GPC) against a polystyrene standard.
The polysulfone of bisphenol A is mostly preferred.
Aliphatic polyethers (B) to be used according to the invention are hydroxyl group-containing polyethers with at least one, especially two to eight hydroxyl groups and a molecular weight (number average) of 400 to 25,000, calculated from the hydroxyl number in conjunction with the functionality. Such polyethers with at least one, preferably two to three, particularly preferably two hydroxyl groups are known and are produced e.g., by polymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran or styrene oxide with themselves, e.g., in the presence of Lewis catalysts such as BF
3
, or by addition of these epoxides, preferably of ethylene oxide and propylene oxide, optionally mixed together or consecutively, to initiator components with reactive hydrogen atoms such as water, alcohols, ammonia or amines, e.g., ethylene glycol, 1,3- or 1,2-propylene glycol, trimethylolpropane, glycerol, sorbitol, 4,4′-dihydroxy-diphenylpropane, aniline, ethanolamine or ethylenediamine. Sucrose polyethers (e.g., DE-AS 1,176,358 and 1,064,938) and polyethers initiated on formitol or formose (DE-OS 2,639,983 and 2,737,951, respectively) are also suitable according to the invention.
Those polyethers having predominantly (based on all OH groups) in the polyether primary OH groups are preferred. Preferably the polyethers have at least 90 wt. % primary OH groups. Particularly preferred are polyethers having 100 wt. % or nearly 100 wt. % of primary OH groups.
Component B) also comprises polythioethers, especially the condensation products of thiodiglycol with itself and/or with other glycols or formaldehyde.
In addition, polyacetals, e.g., the compounds that can be produced from glycols such as diethylene glycol, triethylene glycol, 4,4′-dioxethoxy-diphenyldimethylmethane, hexanediol and formaldehyde are suitable. Compounds (B) which can be used according to the invention can also be produced by polymerizing cyclic acetals such as, e.g., trioxane (DE-Offenlegungsschrift 1 694 128).
Preferred aliphatic polyethers (B) are polyethers of the general structural formula
H—(O—(CH
2
—CH
2
)
n
—)
m
—OH
with n=1 or 2 and m=natural number from 1 to 500.
Particularly preferred aliphatic polyethers are, e.g., polyethylene glycol with molecular weights of 400 to 20,000 (number average) and an OH functionality of about 2 or polytetrahydrofuran with a molecular weight of approx. 500 to 10,000 and an OH functionality of about 2.
Mixtures of two or more different polyethers can also be used, “different” relating both to the chemical structure and to the molecular weight of the polyether.
The polyether block copolysulfones generally have molecular weights of between 5000 and 100,000, preferably between 10,000 and 75,000, weight average, measured by GPC against a polystyrene standard.
Basic catalysts (C) which are suitable in principle are, e.g., carbonates such as lithium carbonate, sodium carbonate, sodium hydrogencarbonate, potassium carbonate, potassium hydrogencarbonate, caesium carbonate, magnesium carbonate, calcium carbonate. Potassium carbonate i

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