U.S. patent application number 17/262859 was filed with the patent office on 2021-07-29 for method for producing a polymer which contains double bonds as an elastomer precursor.
The applicant listed for this patent is Covestro Intellectual Property GmbH & Co. KG. Invention is credited to Rene Boltersdorf, Christoph Guertler, Carsten Koopmans, Walter Leitner, Thomas Ernst Mueller, Muhammad Afzal Subhani.
Application Number | 20210230361 17/262859 |
Document ID | / |
Family ID | 1000005551784 |
Filed Date | 2021-07-29 |
United States Patent
Application |
20210230361 |
Kind Code |
A1 |
Subhani; Muhammad Afzal ; et
al. |
July 29, 2021 |
METHOD FOR PRODUCING A POLYMER WHICH CONTAINS DOUBLE BONDS AS AN
ELASTOMER PRECURSOR
Abstract
The present invention relates to a method for producing an
organooxysilyl-crosslinked polymer by reacting a polyether
carbonate polyol which contains carbon-carbon double bonds with a
polysiloxane compound in the presence of a suitable catalyst.
Suitable polysiloxane compounds have at least two Si--H bonds. This
invention also relates to organooxysilyl-crosslinked polymers which
are formed by this process.
Inventors: |
Subhani; Muhammad Afzal;
(Aachen, DE) ; Boltersdorf; Rene; (Gusten, DE)
; Leitner; Walter; (Aachen, DE) ; Mueller; Thomas
Ernst; (Bochum, DE) ; Guertler; Christoph;
(Koln, DE) ; Koopmans; Carsten; (Hilden,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Covestro Intellectual Property GmbH & Co. KG |
Leverkusen |
|
DE |
|
|
Family ID: |
1000005551784 |
Appl. No.: |
17/262859 |
Filed: |
August 2, 2019 |
PCT Filed: |
August 2, 2019 |
PCT NO: |
PCT/EP2019/070851 |
371 Date: |
January 25, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G 64/186 20130101;
C08G 64/34 20130101; C08G 64/0291 20130101; C08G 64/0266 20130101;
C08G 64/42 20130101 |
International
Class: |
C08G 64/34 20060101
C08G064/34; C08G 64/42 20060101 C08G064/42; C08G 64/02 20060101
C08G064/02; C08G 64/18 20060101 C08G064/18 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 7, 2018 |
EP |
18187627.7 |
Claims
1. A process for preparing an organooxysilyl-crosslinked polymer,
comprising reacting a polyethercarbonate polyol containing
carbon-carbon double bonds with a polysiloxane compound in the
presence of a catalyst (A), wherein the polysiloxane compound has
at least two Si--H bonds.
2. The process as claimed in claim 1, wherein the polysiloxane
compound comprises an .alpha.,.omega.-polysiloxane compound.
3. The process as claimed in claim 2, wherein the
.alpha.,.omega.-polysiloxane compound corresponds to a structure of
formula (I): ##STR00005## wherein 1.gtoreq.a.ltoreq.3;
1.gtoreq.h.ltoreq.3; a+b+c=3, f+g+h=3; R.sup.1, R.sup.2, R.sup.5,
and R.sup.6 each independently represent=an alkyl radical, an aryl
radical, or a cycloalkyl radical; R.sup.3 represents
O--SiR.sup.7R.sup.8; wherein, R.sup.7, and R.sup.8 each
independently =represent an alkyl radical, an aryl radical, or a
cycloalkyl radical; d=represents a number from 1 to 100;
R.sup.4=represents O--SiR.sup.9R.sup.10; wherein: R.sup.9, and
R.sup.10 each independently =represent a hydrogen atom, an alkyl,
radical, an aryl radical, or a cycloalkyl radical; and e=represents
a number from 1 to 100.
4. The process as claimed in claim 3, wherein R.sup.1, R.sup.2,
R.sup.3, R.sup.4 R.sup.5 each represent a methyl radical; R.sup.7,
and R.sup.8 each represent a methyl radical; R.sup.9 represents
hydrogen; R.sup.10 represents a methyl radical; d represents a
number from 10 to 60; and e represents a number from 10 to 60.
5. The process as claimed in claim 1, wherein the
polyethercarbonate polyol containing carbon-carbon double bonds is
obtainable by addition of an alkylene oxide, at least one monomer
containing carbon-carbon double bonds and CO2 onto an H-functional
starter compound in the presence of a double metal cyanide
catalyst.
6. The process as claimed in claim 5, wherein the molar ratio of
the saturated alkylene oxides used to the at least one further
monomer containing carbon-carbon double bonds is from 55.0 mol % to
99.5 mol %.
7. The process as claimed in claim 5, wherein the carbon-carbon
double bond-containing monomer is selected from at least one of the
monomers from one or more of the groups consisting of (a) allyl
glycidyl ether, vinylcyclohexene oxide, cyclooctadiene monoepoxide,
cyclododecatriene monoepoxide, butadiene monoepoxide, isoprene
monoepoxide, limonene oxide, 1,4-divinylbenzene monoepoxide,
1,3-divinylbenzene monoepoxide, glycidyl esters of unsaturated
fatty acids, such as oleic acid, linoleic acid, conjuene fatty
acid, or linolenic acid, partly epoxidized fats and oils, such as
partly epoxidized soya oil, linseed oil, rapeseed oil, palm oil or
sunflower oil, and/or mixtures thereof; (b) an alkylene oxide with
a double bond which corresponds to the general formula (IX):
##STR00006## wherein: R.sub.1 to R.sub.3 each independently
represent H, halogen, a substituted or an unsubstituted
C.sub.1-C.sub.22 alkyl radical or a substituted or an unsubstituted
C.sub.6-C 12 aryl radical; (c) a cyclic anhydride corresponding to
the formula (X), (XI) or (XII): ##STR00007## wherein R.sub.1 to
R.sub.10 each independently represent H, halogen, a substituted or
n unsubstituted C.sub.1-C.sub.22 alkyl radical, or a substituted or
an unsubstituted C.sub.6-C.sub.12 aryl; and (d)
4-cyclohexene-1,2-dioic anhydride, 4-methyl-4-cyclohexene-1,2-dioic
anhydride, 5,6-norbomene-2,3-dioic anhydride,
allyl-5,6-norbomene-2,3-dioic anhydride, dodecenylsuccinic
anhydride, tetradecenylsuccinic anhydride, hexadecenylsuccinic
anhydride and octadecenylsuccinic anhydride.
8. The process as claimed in claim 7, wherein the carbon-carbon
double bond-containing monomer is selected from at least one of the
monomers from one or more of the groups consisting of (a) allyl
glycidyl ether, vinylcyclohexene oxide and limonene oxide, (b)
glycidyl acrylate and glycidyl methacrylate, (c) maleic anhydride
and itaconic anhydride and (d) 4-cyclohexene-1,2-dioic anhydride
and 5,6-norbomene-2,3-dioic anhydride.
9. The process as claimed in claim 1, wherein the
polyethercarbonate polyol containing carbon-carbon double bonds has
a CO.sub.2 content of 0.5% by weight to 50% by weight.
10. The process as claimed in claim 1, wherein the molar ratio of
the carbon-carbon double bonds in the polyethercarbonate polyol to
the Si--H bonds of the polysiloxane compound is from 1:10 to
10:1.
11. The process as claimed in claim 1, the catalyst (A) is a
hydrosilylation catalyst.
12. The process as claimed in claim 11, wherein the hydrosilylation
catalyst is one or more compound(s) and is selected from the group
consisting of Karstedt catalysts, Speier catalysts, elemental
platinum and elemental platinum on a support of activated carbon or
alumina.
13. The process as claimed in claim 11, wherein the hydrosilylation
catalyst is one or more compound(s) and is selected from the group
consisting of
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane,
hexachloroplatinic acid,
pentamethylcyclopentadienyl-tris(acetonitrile)-ruthenium(II)
hexafluorophosphate, bis(1,5-cyclooctadiene)rhodium(I)
tetrafluoroborate, (bicyclo[2.2.1]hepta-2,5-diene)rhodium(I)
chloride dimer, tris(triphenylphosphine)rhodium(I) chloride,
benzenedichlororuthenium(II) dimer, dichloro(p-cymene)ruthenium(II)
dimer and
benzylidenebis(tricyclohexylphosphine)dichlororuthenium(II).
14. An organooxysilyl-crosslinked polymer obtainable by a process
as claimed in claim 1, wherein the organooxysilyl end group has a
number-average molecular weight M.sub.n of .gtoreq.500 g/mol to
.ltoreq.100 000 g/mol, which has been determined by means of GPC.
Description
[0001] The present invention relates to a process for preparing an
organooxysilyl-crosslinked polymer, comprising the reaction of a
polyethercarbonate polyol containing carbon-carbon double bonds
with a polysiloxane compound in the presence of a catalyst (A),
wherein the polysiloxane compound has at least two Si--H bonds. A
further subject is organooxysilyl-crosslinked polymers obtainable
by the process of the invention.
[0002] The preparation of polyethercarbonate polyols by catalytic
reaction of alkylene oxides (epoxides) and carbon dioxide in the
presence of H-functional starter substances ("starters") has been
the subject of intensive study for more than 40 years (e.g. Inoue
et al., Copolymerization of Carbon Dioxide and Epoxide with
Organometallic Compounds; Die Makromolekulare Chemie 130, 210-220,
1%9). This reaction is shown in schematic form in scheme (I), where
R is an organic radical such as alkyl, alkylaryl or aryl, each of
which may also contain heteroatoms, for example O, S, Si, etc., and
where e, f and g are each integers, and where the product shown
here in scheme (I) for the polyethercarbonate polyol should merely
be understood in such a way that blocks having the structure shown
may in principle be present in the polyethercarbonate polyol
obtained, but the sequence, number and length of the blocks and the
OH functionality of the starter may vary and is not restricted to
the polyethercarbonate polyol shown in scheme (I). This reaction
(see scheme (I)) is highly advantageous from an environmental
standpoint since this reaction is the conversion of a greenhouse
gas such as CO.sub.2 to a polymer. A further product formed,
actually a by-product, is the cyclic carbonate shown in scheme (I)
(for example, when R.dbd.CH.sub.3, propylene carbonate).
##STR00001##
[0003] EP 2 845 872 A1 discloses a process for preparing
polyethercarbonate polyols with side chains, comprising the steps
of: (.alpha.) initially charging a catalyst and (.alpha..alpha.) a
suspension medium that does not contain any H-functional groups
and/or (.alpha..beta.) an H-functional starter compound; (.gamma.)
metering in carbon dioxide and at least two alkylene oxides, where
these alkylene oxides may be the same as or different than the
alkylene oxide(s) metered in in step (.beta.), where the difference
in the molecular weight of the lightest and heaviest of the
alkylene oxides metered in in stage (.gamma.) is not less than 24
g/mol and the lightest alkylene oxide is a C2-C4-alkylene oxide and
where, in addition, if no H-functional starter compound has been
initially introduced in step (.alpha.), step (.gamma.) comprises
the metered addition of an H-functional starter compound. Also
claimed is the use of the polyethercarbonate polyol as
crosslinkable component within a crosslinking reaction for
production of thermoset or elastomeric networks.
[0004] Unsaturated polyethercarbonate polyols are crosslinkable via
their double bonds. For instance, WO 2015/032645 A1 discloses a
process for preparing mercapto-crosslinked polyethercarbonates,
with reaction of polyethercarbonate polyols containing double bonds
with polyfunctional mercaptans with involvement of initiator
compounds.
[0005] Another conceivable crosslinking reaction is the reaction of
the unsaturated polyethercarbonate polyols with free-radical
initiators. However, their molecular weight achievable according to
the current prior art is too low at least by a factor of 10 for use
of the unsaturated polyethercarbonate polyols in the production of
elastomers. This is the case especially when the double bonds in
the polyurethanes prepared therefrom are to remain intact at first.
Polyethercarbonate polyols cannot be processed directly on machines
that are used in the production of elastomers the the currently
available polyethercarbonate polyols are liquid compounds having
high adhesion on metal surfaces.
[0006] It is desirable to perform the preparation of elastomers in
a two-stage process. In a first step, an elastomer precursor that
has still not reacted to give a fixed three-dimensional network and
is therefore processible on machines and especially formable is
provided. The crosslinking step that follows then affords the
elastomer.
[0007] It is an object of the present invention to provide a
process for preparing an elastomer precursor, in which it is
possible to use currently available polyethercarbonate polyols
regardless of their molecular weight, and in which good
compatibility of the polyethercarbonate with fillers can be
achieved without attachment via siloxane bridges.
[0008] The object was achieved in accordance with the invention by
a process for preparing an organooxysilyl-crosslinked polymer,
comprising the reaction of a polyethercarbonate polyol containing
carbon-carbon double bonds with a polysiloxane compound in the
presence of a catalyst (A), wherein the polysiloxane compound has
at least two Si--H bonds.
[0009] Polysiloxane Compound
[0010] Polysiloxane compound in the context of the invention is
understood to mean a compound containing .gtoreq.2 Si--H groups.
Preferred compounds are silicone oils having the general empirical
formula [R.sup.1R.sup.2SiO].sub.n that contain .gtoreq.2 Si--H
groups. The Si--H groups may be present as terminal groups
(.alpha.,.omega.-an .alpha.,.omega.-polysiloxane compound), may be
present along the siloxane chain or may be bound to side
chains.
[0011] In a preferred embodiment of the process, the polysiloxane
compound is an .alpha.,.omega.-polysiloxane compound.
[0012] In a preferred embodiment of the process, the
.alpha.,.omega.-polysiloxane compound has a structure of formula
(I):
##STR00002##
[0013] with 1.gtoreq.a.ltoreq.3; 1.gtoreq.h.ltoreq.3; a+b+c=3,
f+g+h=3; R.sup.1, R.sup.2, R.sup.5, R.sup.6 independently=alkyl,
aryl, cycloalkyl, preferably alkyl, more preferably Me, Et, Pr;
R.sup.3=O--SiR.sup.7R.sup.8; R.sup.7, R.sup.8 independently=alkyl,
aryl, cycloalkyl, preferably alkyl, more preferably Me, Et, Pr; d=1
to 100; preferably 5 to 80; R.sup.4=O--SiR.sup.9R.sup.10; R.sup.9,
R.sup.10 independently=hydrogen, alkyl, aryl, cycloalkyl,
preferably hydrogen, alkyl, more preferably hydrogen, Me, Et, Pr,
e=1 to 100; preferably 5 to 80.
[0014] The R.sup.3 and R.sup.4 radicals here, in the above-defined
repeat units d and e, may independently occur in a statistical,
alternating or blockwise manner with respect to one another.
[0015] In a particularly preferred embodiment of the process,
R.sup.1=R.sup.2=R.sup.3=R.sup.4=R.sup.5=Me; R.sup.7=R.sup.8=Me;
R.sup.9=hydrogen; R.sup.10=Me; d=10 to 60; e=10 to 60.
[0016] Polyetherrarbonate Polyol
[0017] Unless indicated otherwise, the term "double bond" in the
context of the present application means a carbon-carbon double
bond that is not part of an aromatic system.
[0018] In the process of the invention, polyethercarbonate polyols
are also understood to mean polyethercarbonate polyols,
polyetherpolyestercarbonate polyols and/or polycarbonate
polyols.
[0019] In a further configuration of the process of the invention,
the polyethercarbonate polyol containing carbon-carbon double bonds
has a content of carbon-carbon double bonds of 0.5% by weight to
17.0% by weight, preferably of 1.0% by weight to 6.0% by
weight.
[0020] The content of carbon-carbon carbon-carbon double bonds in
the polyethercarbonate polyol for the polyethercarbonate polyol
containing carbon-carbon double bonds is found as the quotient of
the reported double bond content of the polyethercarbonate polyols
used reported in C.sub.2H.sub.2 equivalents per unit total mass of
the polyethercarbonate polyol, and is reported in C.sub.2H.sub.2
equivalents per unit mass of polyethercarbonate polyol.
[0021] In a further configuration of the process of the invention,
the polyethercarbonate polyol containing carbon-carbon double bonds
has a CO.sub.2 content of 0.5% by weight to 50/by weight,
preferably of 5% by weight to 25% by weight.
[0022] In a further configuration of the process of the invention,
the polyethercarbonate polyol containing carbon-carbon double bonds
is obtainable by addition of an alkylene oxide, at least one
monomer containing carbon-carbon double bonds and CO.sub.2 onto an
H-functional starter compound in the presence of a double metal
cyanide catalyst.
[0023] In the process of the invention, alkylene oxides used may be
alkylene oxides having 2-45 carbon atoms. The alkylene oxides
having 2-45 carbon atoms are, for example, one or more compounds
selected from the group comprising ethylene oxide, propylene oxide,
1-butene oxide, 2,3-butene oxide, 2-methyl-1,2-propene oxide
(isobutene oxide), 1-pentene oxide, 2,3-pentene oxide,
2-methyl-1,2-butene oxide, 3-methyl-1,2-butene oxide, alkylene
oxides of C6-C22 .alpha.-olefins, such as 1-hexene oxide,
2,3-hexene oxide, 3,4-hexene oxide, 2-methyl-1,2-pentene oxide,
4-methyl-1,2-pentene oxide, 2-ethyl-1,2-butene oxide, 1-heptene
oxide, 1-octene oxide, 1-nonene oxide, 1-decene oxide, 1-undecene
oxide, 1-dodecene oxide, 4-methyl-1,2-pentene oxide, cyclopentene
oxide, cyclohexene oxide, cycloheptene oxide, cyclooctene oxide,
styrene oxide, methylstyrene oxide, pinene oxide, mono- or
polyepoxidized fats as mono-, di- and triglycerides, epoxidized
fatty acids, C1-C24 esters of epoxidized fatty acids,
epichlorohydrin, glycidol, and derivatives of glycidol, for example
glycidyl ethers of C1-C22 alkanols and glycidyl esters of C1-C22
alkanecarboxylic acids. Examples of derivatives of glycidol are
phenyl glycidyl ether, cresyl glycidyl ether, methyl glycidyl
ether, ethyl glycidyl ether and 2-ethylhexyl glycidyl ether.
Alkylene oxides used are preferably ethylene oxide and/or propylene
oxide, especially propylene oxide. If ethylene oxide and propylene
oxide are used in a mixture, the molar EO/PO ratio is 1:99 to 99:1,
preferably 5:95 to 50:50. If ethylene oxide and/or propylene oxide
are used in a mixture with other unsaturated alkylene oxides, the
proportion thereof is 1 to 40 mol %, preferably 2 to 20 mol %.
[0024] An example of a catalyst that may be used for preparing the
polyethercarbonate polyols according to the invention is a DMC
catalyst (double metal cyanide catalyst). Other catalysts may also
be employed alternatively or in addition. For the copolymerization
of alkylene oxides and CO.sub.2, zinc carboxylates or cobalt salen
complexes for example may be employed alternatively or in addition.
Examples of suitable zinc carboxylates are zinc salts of carboxylic
acids, especially dicarboxylic acids such as adipic acid or
glutaric acid. An overview of the known catalysts for the
copolymerization of alkylene oxides and CO.sub.2 is provided, for
example, by Chemical Communications 47 (2011) 141-163.
[0025] The catalyst is preferably a DMC catalyst.
[0026] The double metal cyanide compounds present DMC catalysts
that are usable with preference in the process of the invention are
the reaction products of water-soluble metal salts and
water-soluble metal cyanide salts.
[0027] Double metal cyanide (DMC) catalysts for use in the
homopolymerization of alkylene oxides are known in principle from
the prior art (see, for example, U.S. Pat. Nos. 3,404,109,
3,829,505, 3,941,849 and 5,158,922). DMC catalysts which are
described in, for example, U.S. Pat. No. 5,470,813, EP-A 700 949,
EP-A 743 093, EP-A 761 708, WO 97/40086, WO 98/16310 and WO
00/47649 possess a very high activity and permit the production of
polyethercarbonates at very low catalyst concentrations. A typical
example is that of the highly active DMC catalysts described in
EP-A 700 949 which, as well as a double metal cyanide compound
(e.g. zinc hexacyanocobaltate(III)) and an organic complex ligand
(e.g. tert-butanol), also contain a polyether having a
number-average molecular weight greater than 500 g/mol.
[0028] The DMC catalysts which can be used in accordance with the
invention are preferably obtained by [0029] (1.) in the first step,
reacting an aqueous solution of a metal salt with the aqueous
solution of a metal cyanide salt in the presence of one or more
organic complex ligands, e.g. an ether or alcohol, [0030] (2.) in
the second step, using known techniques (such as centrifuging or
filtering) to remove the solid from the suspension obtained from
(a), [0031] (3.) optionally, in a third step, washing the isolated
solid with an aqueous solution of an organic complex ligand (e.g.
by resuspending and subsequently again isolating by filtering or
centrifuging), [0032] (4.) and subsequently drying the resulting
solid, optionally after pulverizing, at temperatures of in general
20-120.degree. C. and at pressures of in general 0.1 mbar to
atmospheric pressure (1013 mbar),
[0033] and wherein, in the first step or immediately after the
precipitation of the double metal cyanide compound (second step),
one or more organic complex ligands, preferably in excess (based on
the double metal cyanide compound), and optionally further
complex-forming components are added.
[0034] The double metal cyanide compounds included in the DMC
catalysts that are usable in accordance with the invention are the
reaction products of water-soluble metal salts and water-soluble
metal cyanide salts.
[0035] By way of example, an aqueous zinc chloride solution
(preferably in excess relative to the metal cyanide salt) and
potassium hexacyanocobaltate are mixed and then dimethoxyethane
(glyme) or tert-butanol (preferably in excess, relative to zinc
hexacyanocobaltate) is added to the resulting suspension.
[0036] Metal salts suitable for preparation of the double metal
cyanide compounds preferably have a composition according to the
general formula (II),
M(X).sub.n (II)
[0037] where
[0038] M is selected from the metal cations Zn.sup.2+, Fe.sup.2+,
Ni.sup.2+, Mn.sup.2+, Co.sup.2+, Sr.sup.2+, Sn.sup.2+, Pb.sup.2+
and Cu.sup.2+; M is preferably Zn.sup.2+, Fe.sup.2+, Co.sup.2+ or
Ni.sup.2+,
[0039] X are one or more (i.e. different) anions, preferably an
anion selected from the group of the halides (i.e. fluoride,
chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate,
thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and
nitrate;
[0040] n is 1 if X=sulfate, carbonate or oxalate and
[0041] n is 2 if X=halide, hydroxide, carboxylate, cyanate,
thiocyanate, isocyanate, isothiocyanate or nitrate,
[0042] or suitable metal salts preferably have a composition
according to the general formula (III)
M.sub.r(X)3 (III)
[0043] where
[0044] M is selected from the metal cations Fe.sup.3+, Al.sup.3+,
Co.sup.3+ and Cr.sup.3+,
[0045] X comprises one or more (i.e. different) anions, preferably
an anion selected from the group of the halides (i.e. fluoride,
chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate,
thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and
nitrate;
[0046] r is 2 if X=sulfate, carbonate or oxalate and
[0047] r is 1 if X=halide, hydroxide, carboxylate, cyanate,
thiocyanate, isocyanate, isothiocyanate or nitrate,
[0048] or suitable metal salts preferably have a composition
according to the general formula (IV)
M(X).sub.s (IV)
[0049] where
[0050] M is selected from the metal cations Mo.sup.4+, V.sup.4+ and
W.sup.4+,
[0051] X comprises one or more (i.e. different) anions, preferably
an anion selected from the group of the halides (i.e. fluoride,
chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate,
thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and
nitrate;
[0052] s is 2 if X=sulfate, carbonate or oxalate and
[0053] s is 4 if X=halide, hydroxide, carboxylate, cyanate,
thiocyanate, isocyanate, isothiocyanate or nitrate,
[0054] or suitable metal salts preferably have a composition
according to the general formula (V)
M(X).sub.t (V)
[0055] where
[0056] M is selected from the metal cations Mo.sup.6+ and
W.sup.6+,
[0057] X comprises one or more (i.e. different) anions, preferably
anions selected from the group of the halides (i.e. fluoride,
chloride, bromide, iodide), hydroxide, sulfate, carbonate, cyanate,
thiocyanate, isocyanate, isothiocyanate, carboxylate, oxalate and
nitrate;
[0058] t is 3 if X=sulfate, carbonate or oxalate and
[0059] t is 6 if X=halide, hydroxide, carboxylate, cyanate,
thiocyanate, isocyanate, isothiocyanate or nitrate.
[0060] Examples of suitable metal salts are zinc chloride, zinc
bromide, zinc iodide, zinc acetate, zinc acetylacetonate, zinc
benzoate, zinc nitrate, iron(II) sulfate, iron(II) bromide,
iron(II) chloride, iron(III) chloride, cobalt(II) chloride,
cobalt(II) thiocyanate, nickel(II) chloride and nickel(II) nitrate.
It is also possible to use mixtures of different metal salts.
[0061] Metal cyanide salts suitable for preparing the double metal
cyanide compounds preferably have a composition according to the
general formula (VI)
(Y).sub.aM'(CN).sub.b(A).sub.c (VI)
[0062] where
[0063] M' is selected from one or more metal cations from the group
consisting of Fe(II), Fe(III), Co(II), Co(III), Cr(II), Cr(III),
Mn(II), Mn(III), Ir(III), Ni(II), Rh(III), Ru(II), V(IV) and V(V);
M' is preferably one or more metal cations from the group
consisting of Co(II), Co(III), Fe(II), Fe(III), Cr(III), Ir(III)
and Ni(II),
[0064] Y is selected from one or more metal cations from the group
consisting of alkali metal (i.e. Li.sup.+, Na.sup.+, K.sup.+,
Rb.sup.+) and alkaline earth metal (i.e. Be.sup.2+, Mg.sup.2+,
Ca.sup.2+, Sr.sup.2+, Ba.sup.2+),
[0065] A is selected from one or more anions from the group
consisting of halides (i.e. fluoride, chloride, bromide, iodide),
hydroxide, sulfate, carbonate, cyanate, thiocyanate, isocyanate,
isothiocyanate, carboxylate, azide, oxalate or nitrate, and
[0066] a, b and c are integers, the values for a, b and c being
selected such as to ensure the electronic neutrality of the metal
cyanide salt; a is preferably 1, 2, 3 or 4; b is preferably 4, 5 or
6; c preferably has the value 0.
[0067] Examples of suitable metal cyanide salts are sodium
hexacyanocobaltate(III), potassium hexacyanocobaltate(III),
potassium hexacyanoferrate(II), potassium hexacyanoferrate(III),
calcium hexacyanocobaltate(III) and lithium
hexacyanocobaltate(III).
[0068] Preferred double metal cyanide compounds included in the DMC
catalysts which can be used in accordance with the invention are
compounds having compositions according to the general formula
(VII)
M.sub.x[M'.sub.x,(CN).sub.y].sub.z (VII)
[0069] in which M is defined as in the formulae (I) to (IV) and
[0070] M' is as defined in formula (V), and
[0071] x, x', y and z are integers and are selected such as to
ensure the electronic neutrality of the double metal cyanide
compound.
[0072] Preferably,
[0073] x=3, x'=1, y=6 and z=2,
[0074] M=Zn(II), Fe(II), Co(I) or Ni(II) and
[0075] M'=Co(III), Fe(III), Cr(III) or Ir(III).
[0076] Examples of suitable double metal cyanide compounds a) are
zinc hexacyanocobaltate(III), zinc hexacyanoiridate(III), zinc
hexacyanoferrate(III) and cobalt(II) hexacyanocobaltate(III).
Further examples of suitable double metal cyanide compounds can be
found, for example, in U.S. Pat. No. 5,158,922 (column 8, lines
29-66). With particular preference it is possible to use zinc
hexacyanocobaltate(III).
[0077] The organic complex ligands which can be added in the
preparation of the DMC catalysts are disclosed in, for example,
U.S. Pat. No. 5,158,922 (see, in particular, column 6, lines 9 to
65), U.S. Pat. Nos. 3,404,109, 3,829,505, 3,941,849, EP-A 700 949,
EP-A 761708, JP 4 145 123, U.S. Pat. No. 5,470,813, EP-A 743 093
and WO-A 97/40086. For example, organic complex ligands used are
water-soluble organic compounds having heteroatoms, such as oxygen,
nitrogen, phosphorus or sulfur, which can form complexes with the
double metal cyanide compound. Preferred organic complex ligands
are alcohols, aldehydes, ketones, ethers, esters, amides, ureas,
nitriles, sulfides and mixtures thereof. Particularly preferred
organic complex ligands are aliphatic ethers (such as
dimethoxyethane), water-soluble aliphatic alcohols (such as
ethanol, isopropanol, n-butanol, isobutanol, sec-butanol,
tert-butanol, 2-methyl-3-buten-2-ol and 2-methyl-3-butyn-2-ol),
compounds which include both aliphatic or cycloaliphatic ether
groups and aliphatic hydroxyl groups (such as ethylene glycol
mono-tert-butyl ether, diethylene glycol mono-tert-butyl ether,
tripropylene glycol monomethyl ether and 3-methyl-3-oxetanemetanol,
for example). Extremely preferred organic complex ligands are
selected from one or more compounds of the group consisting of
dimethoxyethane, tert-butanol, 2-methyl-3-buten-2-ol,
2-methyl-3-butyn-2-ol, ethylene glycol mono-tert-butyl ether and
3-methyl-3-oxetanemethanol.
[0078] In the preparation of the DMC catalysts that can be used in
accordance with the invention, there is optional use of one or more
complex-forming components from the compound classes of the
polyethers, polyesters, polycarbonates, polyalkylene glycol
sorbitan esters, polyalkylene glycol glycidyl ethers,
polyacrylamide, poly(acrylamide-co-acrylic acid), polyacrylic acid,
poly(acrylic acid-co-maleic acid), polyacrylonitrile, polyalkyl
acrylates, polyalkyl methacrylates, polyvinyl methyl ether,
polyvinyl ethyl ether, polyvinyl acetate, polyvinyl alcohol,
poly-N-vinylpyrrolidone, poly(N-vinylpyrrolidone-co-acrylic acid),
polyvinyl methyl ketone, poly(4-vinylphenol), poly(acrylic
acid-co-styrene), oxazoline polymers, polyalkyleneimines, maleic
acid copolymers and maleic anhydride copolymers,
hydroxyethylcellulose and polyacetals, or of the glycidyl ethers,
glycosides, carboxylic esters of polyhydric alcohols, bile acids or
salts, esters or amides thereof, cyclodextrins, phosphorus
compounds, .alpha.,.beta.-unsaturated carboxylic esters, or ionic
surface-active or interface-active compounds.
[0079] In the preparation of the DMC catalysts that can be used in
accordance with the invention, preference is given to using the
aqueous solutions of the metal salt (e.g. zinc chloride) in the
first step in a stoichiometric excess (at least 50 mol %) relative
to the metal cyanide salt. This corresponds to at least a molar
ratio of metal salt to metal cyanide salt of 2.25:1.00. The metal
cyanide salt (e.g. potassium hexacyanocobaltate) is reacted in the
presence of the organic complex ligand (e.g. tert-butanol) to form
a suspension which contains the double metal cyanide compound (e.g.
zinc hexacyanocobaltate), water, excess metal salt, and the organic
complex ligand.
[0080] The organic complex ligand may be present in the aqueous
solution of the metal salt and/or of the metal cyanide salt or it
is added directly to the suspension obtained after precipitation of
the double metal cyanide compound. It has been found to be
advantageous to mix the metal salt and the metal cyanide salt
aqueous solutions and the organic complex ligand by stirring
vigorously. Optionally, the suspension formed in the first step is
subsequently treated with a further complex-forming component. This
complex-forming component is preferably used in a mixture with
water and organic complex ligand. A preferred process for
performing the first step (i.e. the preparation of the suspension)
is effected using a mixing nozzle, particularly preferably using a
jet disperser, as described, for example, in WO-A 01/39883.
[0081] In the second step, the solid (i.e. the precursor of the
catalyst) can be isolated from the suspension by known techniques,
such as centrifugation or filtration.
[0082] In a preferred execution variant, the isolated solid is
subsequently washed in a third process step with an aqueous
solution of the organic complex ligand (for example by resuspension
and subsequent reisolation by filtration or centrifugation). In
this way, for example, water-soluble by-products, such as potassium
chloride, can be removed from the catalyst that can be used in
accordance with the invention. Preferably, the amount of the
organic complex ligand in the aqueous wash solution is between 40%
and 80% by weight, based on the overall solution.
[0083] Optionally, in the third step, the aqueous wash solution is
admixed with a further complex-forming component, preferably in the
range between 0.5% and 5% by weight, based on the overall
solution.
[0084] It is also advantageous to wash the isolated solid more than
once. In a first washing step (3.-1), washing is preferably
effected with an aqueous solution of the unsaturated alcohol (for
example by resuspension and subsequent reisolation by filtration or
centrifugation), in order thereby to remove, for example,
water-soluble by-products, such as potassium chloride, from the
catalyst usable in accordance with the invention. The amount of the
unsaturated alcohol in the aqueous wash solution is more preferably
between 40% and 80% by weight, based on the overall solution of the
first washing step. In the further washing steps (3.-2), either the
first washing step is repeated one or more times, preferably from
one to three times, or, preferably, a nonaqueous solution, such as
a mixture or solution of unsaturated alcohol and further
complex-forming component (preferably in the range between 0.5% and
5% by weight, based on the total amount of the wash solution of
step (3.-2)), is employed as the wash solution, and the solid is
washed with it one or more times, preferably one to three
times.
[0085] The isolated and optionally washed solid can then be dried,
optionally after pulverization, at temperatures of 20-100.degree.
C. and at pressures of 0.1 mbar to atmospheric pressure (1013
mbar).
[0086] One preferred method for isolating the DMC catalysts usable
in accordance with the invention from the suspension by filtration,
filtercake washing and drying is described in WO-A 01/80994.
[0087] For the preparation of the polyethercarbonate polyols of the
invention, in addition, at least one H-functional starter compound
is used.
[0088] As suitable H-functional starter compounds (starters) it is
possible to use compounds having H atoms that are active in respect
of the alkoxylation. Alkoxylation-active groups having active H
atoms are, for example, --OH, --NH.sub.2 (primary amines), --NH--
(secondary amines), --SH, and --CO.sub.2H, preferably --OH and
--NH.sub.2, more preferably --OH. The H-functional starter
substance selected may, for example, be one or more compounds from
the group comprising mono- or polyhydric alcohols, polyfunctional
amines, polyfunctional thiols, amino alcohols, thio alcohols,
hydroxy esters, polyether polyols, polyester polyols,
polyesterether polyols, polyethercarbonate polyols, polycarbonate
polyols, polycarbonates, polyethyleneimines, polyetheramines (e.g.
so-called Jeffamine.RTM. products from Huntsman, such as D-230,
D-400, D-2000, T-403, T-3000, T-5000 or corresponding products from
BASF, such as Polyetheramine D230, D400, D200, T403, T5000),
polytetrahydrofurans (e.g. PolyTHF.RTM. from BASF, such as
PolyTHF.RTM. 250, 650S, 1000, 1000S, 1400, 1800, 2000),
polytetrahydrofuranamines (BASF product Polytetrahydrofuranamine
1700), polyetherthiols, polyacrylate polyols, castor oil, the mono-
or diglyceride of ricinoleic acid, monoglycerides of fatty acids,
chemically modified mono-, di- and/or triglycerides of fatty acids,
and C1-C24 alkyl fatty acid esters which contain on average at
least 2 OH groups per molecule. The C1-C23 alkyl fatty acid esters
containing an average of at least 2 OH groups per molecule are, for
example, commercial products such as Lupranol Balance.RTM. (BASF
AG), Merginol.RTM. products (Hobum Oleochemicals GmbH),
Sovermol.RTM. products (Cognis Deutschland GmbH & Co. KG), and
Soyol.TM. products (USSC Co.).
[0089] Monofunctional starter compounds used may be alcohols,
amines, thiols, and carboxylic acids. Monofunctional alcohols that
may be used include: methanol, ethanol, 1-propanol, 2-propanol,
1-butanol, 2-butanol, tert-butanol, 3-buten-1-ol, 3-butyn-1-ol,
2-methyl-3-buten-2-ol, 2-methyl-3-butyn-2-ol, propargyl alcohol,
2-methyl-2-propanol, 1-tert-butoxy-2-propanol, 1-pentanol,
2-pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol,
1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol,
3-octanol, 4-octanol, phenol, 2-hydroxybiphenyl, 3-hydroxybiphenyl,
4-hydroxybiphenyl, 2-hydroxypyridine, 3-hydroxypyridine,
4-hydroxypyridine. Useful monofunctional amines include:
butylamine, tert-butylamine, pentylamine, hexylamine, aniline,
aziridine, pyrrolidine, piperidine, morpholine. Monofunctional
thiols that may be used include: ethanethiol, 1-propanethiol,
2-propanethiol, 1-butanethiol, 3-methyl-1-butanethiol,
2-butene-1-thiol, thiophenol. Monofunctional carboxylic acids
include: formic acid, acetic acid, propionic acid, butyric acid,
fatty acids such as stearic acid, palmitic acid, oleic acid,
linoleic acid, linolenic acid, benzoic acid, acrylic acid.
[0090] Examples of polyhydric alcohols suitable as H-functional
starter substances are dihydric alcohols (such as, for example,
ethylene glycol, diethylene glycol, propylene glycol, dipropylene
glycol, 1,3-propanediol, 1,4-butanediol, 1,4-butenediol,
1,4-butynediol, neopentyl glycol, 1,5-pentanetanediol,
methylpentanediols (such as, for example,
3-methyl-1,5-pentanediol), 1,6-hexanediol; 1,8-octanediol,
1,10-decanediol, 1,12-dodecanediol, bis(hydroxymethyl)cyclohexanes
(such as, for example, 1,4-bis(hydroxymethyl)cyclohexane),
triethylene glycol, tetraethylene glycol, polyethylene glycols,
dipropylene glycol, tripropylene glycol, polypropylene glycols,
dibutylene glycol and polybutylene glycols); trihydric alcohols
(such as, for example, trimethylolpropane, glycerol,
trishydroxyethyl isocyanurate, castor oil); tetrahydric alcohols
(such as, for example, pentaerythritol); polyalcohols (such as, for
example, sorbitol, hexitol, sucrose, starch, starch hydrolyzates,
cellulose, cellulose hydrolyzates, hydroxy-functionalized fats and
oils, especially castor oil), and also all modification products of
these aforementioned alcohols with different amounts of
.epsilon.-caprolactone.
[0091] The H-functional starter substances may also be selected
from the substance class of the polyether polyols, especially those
having a molecular weight M.sub.n in the range from 100 to 4000
g/mol. Preference is given to polyether polyols formed from repeat
ethylene oxide and propylene oxide units, preferably having a
proportion of propylene oxide units of 35% to 100, more preferably
having a proportion of propylene oxide units of 50/to 100%. These
may be random copolymers, gradient copolymers, alternating
copolymers or block copolymers of ethylene oxide and propylene
oxide. Suitable polyether polyols constructed from repeating
propylene oxide and/or ethylene oxide units are, for example, the
Desmophen.RTM., Acclaim.RTM., Arcol.RTM., Baycoll.RTM.,
Bayfill.RTM., Bayflex.RTM., Baygal.RTM., PET.RTM. and polyether
polyols from Covestro AG (for example Desmophen.RTM. 3600Z,
Desmophen.RTM. 1900U, Acclaim.RTM.Polyol 2200, Acclaim.RTM.Polyol
40001, Arcol.RTM. Polyol 1004, Arcol.RTM. Polyol 1010, Arcol.RTM.
Polyol 1030, Arcol.RTM. Polyol 1070, Baycoll.RTM. BD 1110,
Bayfill.RTM. VPPU 0789, Baygal.RTM. K55, PET.RTM. 1004,
Polyether.RTM. S180). Further suitable homopolyethylene oxides are,
for example, the Pluriol.RTM. E products from BASF SE, suitable
homopolypropylene oxides are, for example, the Pluriol.RTM. P
products from BASF SE; suitable mixed copolymers of ethylene oxide
and propylene oxide are, for example, the Pluronic.RTM. PE or
Pluriol.RTM. RPE products from BASF SE.
[0092] The H-functional starter substances may also be selected
from the substance class of the polyester polyols, especially those
having a molecular weight M.sub.n in the range from 200 to 4500
g/mol. Polyester polyols used may be at least difunctional
polyesters. Polyester polyols preferably consist of alternating
acid and alcohol units. Examples of acid components which can be
used include succinic acid, maleic acid, maleic anhydride, adipic
acid, phthalic anhydride, phthalic acid, isophthalic acid,
terephthalic acid, tetrahydrophthalic acid, tetrahydrophthalic
anhydride, hexahydrophthalic anhydride, or mixtures of the stated
acids and/or anhydrides. Examples of alcohol components used
include ethanediol, 1,2-propanediol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol,
1,4-bis(hydroxymethyl)cyclohexane, diethylene glycol, dipropylene
glycol, trimethylolpropane, glycerol, pentaerythritol, or mixtures
of the stated alcohols. If the alcohol components used are dihydric
or polyhydric polyether polyols, the result is polyesterether
polyols which can likewise serve as starter substances for
preparation of the polyethercarbonate polyols. Preference is given
to using polyether polyols with M.sub.n=150 to 2000 g/mol for
preparation of the polyesterether polyols.
[0093] H-functional starter substances used may additionally be
polycarbonate diols, especially those having a molecular weight
M.sub.n in the range from 150 to 4500 g/mol, preferably 500 to 2500
g/mol, which are prepared, for example, by reaction of phosgene,
dimethyl carbonate, diethyl carbonate or diphenyl carbonate and
difunctional alcohols or polyester polyols or polyether polyols.
Examples for polycarbonates can be found, for example, in EP-A
1359177. Examples of polycarbonate diols that may be used include
the Desmophen.RTM. C range from Covestro AG, for example
Desmophen.RTM.C 1100 or Desmophen.RTM. C 2200.
[0094] In a further embodiment of the invention, it is possible to
use polyethercarbonate polyols and/or polyetherestercarbonate
polyols as H-functional starter substances. In particular, it is
possible to use polyetherestercarbonate polyols. These
polyetherestercarbonate polyols used as H-functional starter
substances may for this purpose be prepared in a separate reaction
step beforehand.
[0095] The H-functional starter substances generally have an OH
functionality (i.e. the number of H atoms active in respect of the
polymerization per molecule) of 1 to 8, preferably of 2 to 6 and
more preferably of 2 to 4. The H-functional starter substances are
used either individually or as a mixture of at least two
H-functional starter substances.
[0096] Preferred H-functional starter substances are alcohols with
a composition according to the general formula (VIII)
[0097] where x is a number from 1 to 20, preferably an even number
from 2 to 20. Examples of alcohols of formula (VII) are ethylene
glycol, butane-1,4-diol, hexane-1,6-diol, octane-1,8-diol,
decane-1,10-diol and dodecane-1,12-diol. Further preferred
H-functional starter substances are neopentyl glycol,
trimethylolpropane, glycerol, pentaerythritol, reaction products of
the alcohols of formula (VII) with .epsilon.-caprolactone, for
example reaction products of trimethylolpropane with
.epsilon.-caprolactone, reaction products of glycerol with
.epsilon.-caprolactone and reaction products of pentaerythritol
with .epsilon.-caprolactone. Preference is further given to using,
as H-functional starter compounds, water, diethylene glycol,
dipropylene glycol, castor oil, sorbitol and polyether polyols
formed from repeating polyalkylene oxide units.
[0098] More preferably, the H-functional starter substances are one
or more compounds selected from the group consisting of ethylene
glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol,
1,4-butanediol, 1,5-pentanediol, 2-methylpropane-1,3-diol,
neopentyl glycol, 1,6-hexanediol, diethylene glycol, dipropylene
glycol, glycerol, trimethylolpropane, di- and trifunctional
polyether polyols, where the polyether polyol has been formed from
a di- or tri-H-functional starter compound and propylene oxide or a
di- or tri-H-functional starter compound, propylene oxide and
ethylene oxide. The polyether polyols preferably have an OH
functionality of 2 to 4 and a molecular weight M.sub.n in the range
from 62 to 4500 g/mol and more particularly a molecular weight
M.sub.n in the range from 62 to 3000 g/mol.
[0099] The CO.sub.2 used in accordance with the invention must have
a purity level of at least 80%, preferably of at least 95%, where
the proportion of sulfur-containing impurities, such as COS or
SO.sub.2, must be below 1% by weight, preferably below 0.1% by
weight. Preference is given to using CO.sub.2 obtained as
by-product in ammonia production, ethylene oxide production, by the
water-gas shift reaction, in combustion processes, preferably in
power plants, or in lime burning. There may be a need for
subsequent purification steps in which sulfur-containing impurities
in particular, but also carbon monoxide, are removed. Inert gases,
such as nitrogen or argon, may be present up to a content of below
20%, preferably below 5%. Particular preference is given to using
CO.sub.2 which is obtained as by-product in ammonia production or
is prepared by water-gas shift reaction since CO.sub.2 from these
sources has particularly low contents of sulfur-containing
impurities.
[0100] In a further configuration of the process, the monomer
containing carbon-carbon double bonds is selected from at least one
of the monomers from one or more of the groups consisting of [0101]
(a) allyl glycidyl ether, vinylcyclohexene oxide, cyclooctadiene
monoepoxide, cyclododecatriene monoepoxide, butadiene monoepoxide,
isoprene monoepoxide, limonene oxide, 1,4-divinylbenzene
monoepoxide, 1,3-divinylbenzene monoepoxide, glycidyl esters of
unsaturated fatty acids, such as oleic acid, linoleic acid,
conjuene fatty acid, or linolenic acid, partly epoxidized fats and
oils, such as partly epoxidized soya oil, linseed oil, rapeseed
oil, palm oil or sunflower oil, and/or mixtures thereof. [0102] (b)
alkylene oxide with double bond of the general formula (IX):
[0102] ##STR00003## [0103] where R.sub.1 to R.sub.3 are
independently H, halogen, substituted or unsubstituted C1-C22 alkyl
or substituted or unsubstituted C6-C12 aryl. As preferred
representatives of the group of the glycidyl esters of
.alpha.,.beta.-unsaturated acids, the compounds of formula (IX)
above display a substitution pattern which is particularly suitable
for the synthesis of polyethercarbonate polyols having unsaturated
groups. This class of compound can be reacted with high yields, by
means of the DMC catalyst employable in accordance with the
invention, to give polyethercarbonate polyols having unsaturated
groups. Furthermore, as a result of the steric and electronic
conditions in the region of the double bond, there may be good
opportunities for further reaction to give higher-molecular-weight,
crosslinked polyethercarbonate polyols. [0104] (c) cyclic anhydride
of the formula (X)(XI) or (XII:
[0104] ##STR00004## [0105] where R.sub.1 to R.sub.10 are
independently H, halogen, substituted or unsubstituted C1-C22 alkyl
or substituted or unsubstituted C6-C12 aryl. Preferred compounds of
the formula (IX), (X), (XI) are maleic anhydride, halogen- or
alkyl-substituted maleic anhydrides, and itaconic anhydride. [0106]
and [0107] (d) 4-cyclohexene-1,2-dioic anhydride,
4-methyl-4-cyclohexene-1,2-dioic anhydride,
5,6-norbornene-2,3-dioic anhydride, allyl-5,6-norbornene-2,3-dioic
anhydride, dodecenylsuccinic anhydride, tetradecenylsuccinic
anhydride, hexadecenylsuccinic anhydride and octadecenylsuccinic
anhydride.
[0108] In a further configuration of the process, the monomer
containing carbon-carbon double bonds is selected from at least one
of the monomers from one or more of the groups consisting of [0109]
(a) allyl glycidyl ether, vinylcyclohexene oxide and limonene
oxide, [0110] (b) glycidyl acrylate and glycidyl methacrylate,
[0111] (c) maleic anhydride and itaconic anhydride [0112] and
[0113] (d) 4-cyclohexene-1,2-dioic anhydride and
5,6-norbornene-2,3-dioic anhydride.
[0114] In a further embodiment of the process of the invention, the
monomer containing carbon-carbon double bonds is selected from
maleic anhydride and/or allyl glycidyl ether, preferably allyl
glycidyl ether.
[0115] The molar ratio of the saturated alkylene oxides used to the
at least one further monomer containing carbon-carbon double bonds
is from 55.0 mol % to 99.5 mol %, preferably from 60.0 mol % to
99.0 mol %.
[0116] The at least one further monomer containing carbon-carbon
double bonds may be in a random or blockwise distribution in the
polyethercarbonate polyols containing carbon-carbon double bonds.
Gradient polymers can also be used.
[0117] The term "terpolymerization" in the sense of the invention
comprehends the polymerization of at least one alkylene oxide, at
least one further monomer containing carbon-carbon double bonds,
and CO.sub.2. Terpolymerization in the sense of the invention also
includes, in particular, the copolymerization of a total of more
than three monomers.
[0118] One preferred embodiment of the process which is usable in
accordance with the invention for preparation of polyethercarbonate
polyols (A-1) containing carbon-carbon double bonds is
characterized in that
[0119] (.alpha.) [first activation stage] a suspension medium
containing no H-functional groups, an H-functional starter
compound, a mixture of a suspension medium which contains no
H-functional groups and an H-functional starter compound, or a
mixture of at least two H-functional starter compounds is
introduced initially, and optionally water and/or other volatile
compounds are removed by elevated temperature and/or reduced
pressure, with the DMC catalyst being added to the suspension
medium which contains no H-functional groups, the H-functional
starter compound, the mixture of a suspension medium which contains
no H-functional groups and the H-functional starter compound, or
the mixture of at least two H-functional starter compounds, before
or after the first activation stage,
[0120] (.beta.) [second activation stage] a portion (based on the
total amount of the amount of alkylene oxides used in steps
(.beta.) and (.gamma.)) of one or more alkylene oxides is added to
the mixture resulting from step (.alpha.), it being possible for
the addition of a portion of alkylene oxide to take place
optionally in the presence of CO.sub.2 and/or inert gas (such as
nitrogen or argon, for example), and it also being possible for
step (.beta.) to take place two or more times,
[0121] (.gamma.) [polymerization stage] one or more alkylene
oxides, at least one unsaturated compound (alkylene oxide and/or
cyclic anhydride), and carbon dioxide are metered continually into
the mixture resulting from step (.beta.), and the alkylene oxides
used for the terpolymerization may be the same as or different from
the alkylene oxides used in step (.beta.).
[0122] There follows a detailed description of this preferred
embodiment using the example of the polyethercarbonate polyols:
[0123] Step (.alpha.):
[0124] The addition of the individual components in step (.alpha.)
may take place simultaneously or in succession in any order;
preferably, in step (.alpha.), the DMC catalyst is introduced
first, and, simultaneously or subsequently, the suspension medium
which contains no H-functional groups, the H-functional starter
compound, the mixture of a suspension medium which contains no
H-functional groups and the H-functional starter compound, or the
mixture of at least two H-functional starter compounds is
added.
[0125] A preferred embodiment provides a process in which, in step
(.alpha.) [first activation stage],
[0126] (.alpha.1) a reactor is charged with the DMC catalyst and a
suspension medium and/or one or more H-functional starter
compounds,
[0127] (.alpha.2) an inert gas (for example, nitrogen or a noble
gas such as argon), an inert gas/carbon dioxide mixture, or carbon
dioxide is passed through the reactor at a temperature of 50 to
200.degree. C., preferably of 80 to 160.degree. C., more preferably
of 125 to 135.degree. C., and at the same time a reduced pressure
(absolute) of 10 mbar to 800 mbar, preferably of 40 mbar to 200
mbar, is set in the reactor by removal of the inert gas or carbon
dioxide (with a pump, for example).
[0128] A further preferred embodiment provides a process in which,
in step (.alpha.) [first activation stage],
[0129] (.alpha.1) a suspension medium which contains no
H-functional groups, an H-functional starter compound, a mixture of
a suspension medium which contains no H-functional groups and an
H-functional starter compound, or a mixture of at least two
H-functional starter compounds is initially introduced, optionally
under inert gas atmosphere, under an atmosphere of inert gas/carbon
dioxide mixture, or under a pure carbon dioxide atmosphere, more
preferably under inert gas atmosphere, and
[0130] (.alpha.2) an inert gas, an inert gas/carbon dioxide mixture
or carbon dioxide, more preferably inert gas, is introduced into
the resulting mixture of the DMC catalyst and the suspension medium
which contains no H-functional groups, the H-functional starter
compound, the mixture of a suspension medium which contains no
H-functional groups and the H-functional starter compound, or the
mixture of at least two H-functional starter compounds, at a
temperature of 50 to 200.degree. C., preferably of 80 to
160.degree. C., more preferably of 125 to 135.degree. C., and at
the same time a reduced pressure (absolute) of 10 mbar to 800 mbar,
preferably of 40 mbar to 200 mbar, is set in the reactor by removal
of the inert gas or carbon dioxide (with a pump, for example),
[0131] it being possible for the double metal cyanide catalyst to
be added to the suspension medium which contains no H-functional
groups, the H-functional starter compound, the mixture of a
suspension medium which contains no H-functional groups and the
H-functional starter compound, or the mixture of at least two
H-functional starter compounds in step (.alpha.1) or immediately
thereafter in step (.alpha.2).
[0132] The DMC catalyst may be added in solid form or in suspension
in a suspension medium and/or in an H-functional starter compound.
If the DMC catalyst is added as a suspension, it is added
preferably in step (.alpha.1) to the suspension medium and/or to
the one or more H-functional starter compounds.
[0133] Step (.beta.):
[0134] Step (.beta.) of the second activation stage may take place
in the presence of CO.sub.2 and/or inert gas. Step (.beta.)
preferably takes place under an atmosphere composed of an inert
gas/carbon dioxide mixture (nitrogen/carbon dioxide or argon/carbon
dioxide, for example) or a carbon dioxide atmosphere, more
preferably under a carbon dioxide atmosphere. The establishment of
an inert gas/carbon dioxide atmosphere or a carbon dioxide
atmosphere and the metering of one or more alkylene oxides may take
place in principle in different ways. The supply pressure is
preferably established by introduction of carbon dioxide, where the
pressure (in absolute terms) is 10 mbar to 100 bar, preferably 100
mbar to 50 bar and especially preferably 500 mbar to 50 bar. The
start of the metered addition of the alkylene oxide may take place
at any supply pressure chosen beforehand. The total pressure (in
absolute terms) of the atmosphere is set in step (.beta.)
preferably in the range from 10 mbar to 100 bar, preferably 100
mbar to 50 bar, and more preferably 500 mbar to 50 bar. Optionally,
during or after the metering of the alkylene oxide, the pressure is
readjusted by introduction of further carbon dioxide, with the
pressure (in absolute terms) being 10 mbar to 100 bar, preferably
100 mbar to 50 bar, and more preferably 500 mbar to 50 bar.
[0135] In one preferred embodiment, the amount of one or more
alkylene oxides used in the case of the activation in step (.beta.)
is 0.1% to 25.0% by weight, preferably 1.0% to 20.0% by weight,
more preferably 2.0% to 16.0% by weight, based on the amount of
suspension medium and/or H-functional starter compound used in step
(.alpha.). The alkylene oxide can be added in one step or stepwise
in two or more portions.
[0136] In one particularly preferred embodiment of the invention, a
portion (based on the total amount of the amount of alkylene oxides
used in steps (.beta.) and (.gamma.)) of one or more alkylene
oxides, in the case of the activation in step (.beta.) [second
activation stage], is added to the mixture resulting from step
(.alpha.), it being possible for the addition of a portion of
alkylene oxide to take place optionally in the presence of CO.sub.2
and/or inert gas. Step (.beta.) may also take place more than once.
The DMC catalyst is preferably used in an amount such that the
content of DMC catalyst in the resulting polyethercarbonate polyol
containing double bonds is 10 ppm to 10 000 ppm, more preferably 20
ppm to 5000 ppm and most preferably 50 ppm to 500 ppm.
[0137] In the second activation step, the alkylene oxide may be
added, for example, in one portion or over the course of 1 to 15
minutes, preferably 5 to 10 minutes. The duration of the second
activation step is preferably 15 to 240 minutes, more preferably 20
to 60 minutes.
[0138] Step (.gamma.):
[0139] The metering of the alkylene oxide(s), of the unsaturated
compounds, also referred to below as monomers, and of the carbon
dioxide may take place simultaneously, alternately, or
sequentially, and the overall amount of carbon dioxide may be added
all at once or in a metered way over the reaction time. During the
addition of the monomers it is possible for the CO.sub.2 pressure,
gradually or in steps, to be raised or lowered or left the same.
The total pressure is preferably kept constant during the reaction
by metered addition of further carbon dioxide. The metering of the
monomers may take place simultaneously, alternately or sequentially
with respect to the metering of carbon dioxide. It is possible to
meter the monomers at a constant metering rate or to raise or lower
the metering rate continuously or in steps, or to add the monomers
in portions. The monomers are preferably added at a constant
metering rate to the reaction mixture. If two or more alkylene
oxides are used for synthesis of the polyethercarbonate polyols
containing double bonds, the alkylene oxides may be metered in
individually or as a mixture. The metered addition of the alkylene
oxides can be effected simultaneously, alternately or sequentially,
each via separate metering points (addition points), or via one or
more metering points, in which case the alkylene oxides can be
metered in individually or as a mixture. Via the nature and/or
sequence of the metering of the monomers and/or of the carbon
dioxide it is possible to synthesize random, alternating, blocklike
or gradientlike polyethercarbonate polyols containing double
bonds.
[0140] Preference is given to using an excess of carbon dioxide,
relative to the calculated amount of carbon dioxide needed in the
polyethercarbonate polyol containing double bonds, since an excess
of carbon dioxide is an advantage, governed by the slowness of
carbon dioxide to react. The amount of carbon dioxide can be
specified by way of the total pressure. A total pressure (absolute)
which has proven advantageous is the range from 0.01 to 120 bar,
preferably 0.1 to 110 bar, more preferably from 1 to 100 bar, for
the copolymerization for preparing the polyethercarbonate polyols
containing double bonds. It is possible to supply the carbon
dioxide to the reaction vessel continuously or discontinuously.
This is dependent on the rate at which the monomers and the
CO.sub.2 are consumed and on whether the product is to include
optionally CO.sub.2-free polyether blocks or blocks with different
CO.sub.2 contents. The concentration of the carbon dioxide may also
vary during the addition of the monomers. Depending on the reaction
conditions selected, it is possible for the CO.sub.2 to be
introduced into the reactor in the gaseous, liquid or supercritical
state. CO.sub.2 can also be added to the reactor in solid form and
then be converted to the gaseous, dissolved, liquid and/or
supercritical state under the chosen reaction conditions.
[0141] In step (.gamma.), the carbon dioxide can be introduced into
the mixture, for example, by [0142] (i) sparging the reaction
mixture in the reactor from below, [0143] (ii) using a hollow-shaft
stirrer, [0144] (iii) a combination of metering forms as per (i)
and (ii), and/or [0145] (iv) sparging via the surface of the
liquid, by using multilevel stirring elements.
[0146] Step (.gamma.) is conducted, for example, at temperatures of
60 to 150.degree. C., preferably from 80 to 120.degree. C., most
preferably from 90 to 110.degree. C. If temperatures below
60.degree. C. are set, the reaction ceases. At temperatures above
150.degree. C., the amount of unwanted by-products rises
significantly.
[0147] The sparging of the reaction mixture in the reactor as per
(i) is preferably effected by means of a sparging ring, a sparging
nozzle, or by means of a gas inlet tube. The sparging ring is
preferably an annular arrangement or two or more annular
arrangements of sparging nozzles, preferably arranged at the bottom
of the reactor and/or on the side wall of the reactor.
[0148] The hollow-shaft stirrer as per (ii) is preferably a stirrer
in which the gas is introduced into the reaction mixture via a
hollow shaft in the stirrer. The rotation of the stirrer in the
reaction mixture (i.e. in the course of mixing) gives rise to a
reduced pressure at the end of the stirrer paddle connected to the
hollow shaft, such that the gas phase (containing CO.sub.2 and any
unconsumed monomers) is sucked out of the gas space above the
reaction mixture and is passed through the hollow shaft of the
stirrer into the reaction mixture.
[0149] The sparging of the reaction mixture as per (i), (ii), (iii)
or (iv) can be effected with freshly metered carbon dioxide in each
case and/or may be combined with suction of the gas from the gas
space above the reaction mixture and subsequent recompression of
the gas. For example, the gas sucked from the gas space above the
reaction mixture and compressed, optionally mixed with fresh carbon
dioxide and/or monomers, is introduced back into the reaction
mixture as per (i), (ii), (iii) and/or (iv).
[0150] The pressure drop which comes about through incorporation of
the carbon dioxide and the monomers into the reaction product in
the terpolymerization is preferably balanced out by means of
freshly metered carbon dioxide.
[0151] The monomers may be introduced separately or together with
the CO.sub.2, either via the liquid surface or directly into the
liquid phase. The monomers are introduced preferably directly into
the liquid phase, since this has the advantage of rapid mixing
between the monomers introduced and the liquid phase, so preventing
local concentration peaks of the monomers. The introduction into
the liquid phase can be effected via one or more inlet tubes, one
or more nozzles or one or more annular arrangements of multiple
metering points, which are preferably arranged at the bottom of the
reactor and/or on the side wall of the reactor.
[0152] The three steps (.alpha.), (.beta.) and (.gamma.) may be
performed in the same reactor or each performed separately in
different reactors. Particularly preferred reactor types are
stirred tanks, tubular reactors and loop reactors. If the reaction
steps (.alpha.), (.beta.) and (.gamma.) are performed in different
reactors, a different reactor type can be used for each step.
[0153] Polyethercarbonate polyols containing double bonds can be
prepared in a stirred tank, in which case the stirred tank,
depending on design and mode of operation, is cooled via the
reactor shell, internal cooling surfaces and/or cooling surfaces
within a pumped circulation system. Both in semibatchwise
application, in which the product is not removed until after the
end of the reaction, and in continuous application, where the
product is removed continuously, particular attention should be
given to the metering rate of the monomers. It should be set so
that, in spite of the inhibitory effect of the carbon dioxide, the
monomers are depleted sufficiently rapidly by reaction. The
concentration of free monomers in the reaction mixture during the
second activation stage (step .beta.) is preferably >0% to 100%
by weight, more preferably >0% to 50% by weight, very preferably
>0% to 20% by weight (based in each case on the weight of the
reaction mixture). The concentration of free monomers in the
reaction mixture during the reaction (step .gamma.) is preferably
>0% to 40% by weight, more preferably >0% to 25% by weight,
very preferably >0% to 15% by weight (based in each case on the
weight of the reaction mixture).
[0154] Another possible embodiment for the copolymerization (step
.gamma.) is characterized in that one or more H-functional starter
compounds as well are metered continuously into the reactor during
the reaction. In the case of performance of the process in
semi-batchwise operation, the amount of the H-functional starter
compounds which are metered continuously into the reactor during
the reaction is preferably at least 20 mol % equivalents, more
preferably 70 to 95 mol % equivalents (based in each case on the
total amount of H-functional starter compounds). In the case of
continuous performance of the process, the amount of the
H-functional starter compounds which are metered continuously into
the reactor during the reaction is preferably at least 80 mol %
equivalents, more preferably 95 to 99.99 mol % equivalents (based
in each case on the total amount of H-functional starter
compounds).
[0155] In one preferred embodiment, the catalyst/starter mixture
activated in steps (.alpha.) and (.beta.) is reacted further in the
same reactor with the monomers and carbon dioxide. In another
preferred embodiment, the catalyst/starter mixture activated in
steps (.alpha.) and (.beta.) is reacted further in a different
reaction vessel (for example, a stirred tank, tubular reactor or
loop reactor) with the monomers and carbon dioxide. In a further
preferred embodiment, the catalyst/starter mixture prepared in step
(.alpha.) is reacted in a different reaction vessel (for example, a
stirred tank, tubular reactor or loop reactor) in steps (.beta.)
and (.gamma.) with the monomers and carbon dioxide.
[0156] In the case of reaction in a tubular reactor, the
catalyst/starter mixture prepared in step (.alpha.), or the
catalyst/starter mixture activated in steps (.alpha.) and (.beta.),
and optionally further starters, and also the monomers and carbon
dioxide, are pumped continuously through a tube. When a
catalyst/starter mixture prepared in step (.alpha.) is used, the
second activation stage in step (.beta.) takes place in the first
part of the tubular reactor, and the terpolymerization in step
(.gamma.) takes place in the second part of the tubular reactor.
The molar ratios of the coreactants vary according to the desired
polymer.
[0157] In one process variant, carbon dioxide is metered in in its
liquid or supercritical form, in order to permit optimum
miscibility of the components. The carbon dioxide can be introduced
at the inlet of the reactor and/or via metering points which are
arranged along the reactor, in the reactor. A portion of the
monomers may be introduced at the inlet of the reactor. The
remaining amount of the monomers is introduced into the reactor
preferably via two or more metering points arranged along the
reactor. Mixing elements, as for example are sold by Ehrfeld
Mikrotechnik BTS GmbH, are advantageously installed for more
effective mixing of the coreactants, or mixer-heat exchanger
elements, which simultaneously improve mixing and heat removal.
Preferably, the mixing elements mix CO.sub.2 which is being metered
in and the monomers with the reaction mixture. In an alternative
embodiment, different volume elements of the reaction mixture are
mixed with one another.
[0158] Loop reactors can likewise be used to prepare
polyethercarbonate polyols containing double bonds. These generally
include reactors having internal and/or external material recycling
(optionally with heat exchanger surfaces arranged in the
circulation system), for example a jet loop reactor or Venturi loop
reactor, which can also be operated continuously, or a tubular
reactor designed in the form of a loop with suitable apparatuses
for the circulation of the reaction mixture, or a loop of several
series-connected tubular reactors or a plurality of
series-connected stirred tanks.
[0159] In order to achieve full conversion, the reaction apparatus
in which step (.gamma.) is carried out may frequently be followed
by a further tank or a tube ("delay tube") in which residual
concentrations of free monomers present after the reaction are
depleted by reaction. Preferably, the pressure in this downstream
reactor is at the same pressure as in the reaction apparatus in
which reaction step (.gamma.) is performed. The pressure in the
downstream reactor can, however, also be selected at a higher or
lower level. In a further preferred embodiment, the carbon dioxide,
after reaction step (.gamma.), is fully or partly released and the
downstream reactor is operated at standard pressure or a slightly
elevated pressure. The temperature in the downstream reactor is
preferably 10 to 150.degree. C. and more preferably 20 to
100.degree. C. At the end of the post-reaction time or at the
outlet of the downstream reactor, the reaction mixture preferably
contains less than 0.05 wt % of monomers. The post-reaction time or
the residence time in the downstream reactor is preferably 10 min
to 24 h, especially preferably 10 min to 3 h.
[0160] In a further preferred embodiment of the process for
preparing the polyethercarbonate polyols, the temperature in step
(.gamma.) may be not less than 60.degree. C. and not more than
150.degree. C. In a particularly preferred embodiment of the
process, the temperature in step (.gamma.) may be not less than
80.degree. C. and not more than 130.degree. C., and very preferably
not less than 90.degree. C. and not more than 120.degree. C. This
temperature range during the polymerization has proven particularly
suitable for synthesis of the polyethercarbonate polyols containing
unsaturated groups with a sufficient reaction rate and with a high
selectivity. In the range of lower temperatures, the reaction rate
which comes about may only be inadequate, and, at higher
temperatures, the fraction of unwanted by-products may increase too
greatly. If temperatures are selected that are too high, there may,
for example, be premature crosslinking of the unsaturated
groups.
[0161] The polyethercarbonate polyols containing double bonds that
are obtainable in accordance with the invention preferably have an
average OH functionality (i.e., average number of OH groups per
molecule) of at least 1, preferably of 1.5 to 10, more preferably
of .gtoreq.2.0 to .ltoreq.4.0.
[0162] The molecular weight of the resulting polyethercarbonate
polyols containing double bonds is preferably at least 400 g/mol,
more preferably 400 to 1 000 000 g/mol and most preferably 500 to
60 000 g/mol.
[0163] The suspension media which are used in step (a) for
suspending the catalyst contain no H-functional groups. Suitable
suspension media are any polar aprotic, weakly polar aprotic and
nonpolar aprotic solvents, none of which contain any H-functional
groups. Suspension media used may also be a mixture of two or more
of these suspension media. Mention is made by way of example at
this point of the following polar aprotic solvents:
4-methyl-2-oxo-1,3-dioxolane (also referred to below as cyclic
propylene carbonate), 1,3-dioxolan-2-one, acetone, methyl ethyl
ketone, acetonitrile, nitromethane, dimethyl sulfoxide, sulfolane,
dimethylformamide, dimethylacetamide and N-methylpyrrolidone. The
group of the nonpolar aprotic and weakly polar aprotic solvents
includes, for example, ethers, for example dioxane, diethyl ether,
methyl tert-butyl ether and tetrahydrofuran, esters, for example
ethyl acetate and butyl acetate, hydrocarbons, for example pentane,
n-hexane, benzene and alkylated benzene derivatives (e.g. toluene,
xylene, ethylbenzene) and chlorinated hydrocarbons, for example
chloroform, chlorobenzene, dichlorobenzene and carbon
tetrachloride. Preferred suspension media used are
4-methyl-2-oxo-1,3-dioxolane, 1,3-dioxolan-2-one, toluene, xylene,
ethylbenzene, chlorobenzene and dichlorobenzene, and mixtures of
two or more of these suspension media; particular preference is
given to 4-methyl-2-oxo-1,3-dioxolane and 1,3-dioxolan-2-one or a
mixture of 4-methyl-2-oxo-1,3-dioxolane and 1,3-dioxolan-2-one.
[0164] In one alternative embodiment, suspension media used in step
(.alpha.) for suspending the catalyst are one or more compounds
selected from the group consisting of aliphatic lactones, aromatic
lactones, lactides, cyclic carbonates having at least three
optionally substituted methylene groups between the oxygen atoms of
the carbonate group, aliphatic cyclic anhydrides, and aromatic
cyclic anhydrides. Without being tied to a theory, suspension media
of this kind are incorporated into the polymer chain in the
subsequent course of the ongoing polymerization in the presence of
a starter. As a result, there is no need for downstream
purification steps.
[0165] Aliphatic or aromatic lactones are cyclic compounds
containing an ester bond in the ring. Preferred compounds are
4-membered-ring lactones such as .beta.-propiolactone,
.beta.-butyrolactone, .beta.-isovalerolactone, .beta.-caprolactone,
.beta.-isocaprolactone, .beta.-methyl-.beta.-valerolactone,
5-membered-ring lactones, such as .gamma.-butyrolactone,
.gamma.-valerolactone, .delta.-methylfuran-2(3H)-one,
5-methylidenedihydrofuran-2(3H)-one, 5-hydroxyfuran-2(5H)-one,
2-benzofuran-(3H)-one and 6-methyl-2-benzofuran-1(3H)-one,
6-membered-ring lactones, such as S-valerolactone,
1,4-dioxan-2-one, dihydrocoumarin, 1H-isochromen-1-one,
8H-pyrano[3,4-b]pyridin-8-one, 1,4-dihydro-3H-isochromen-3-one,
7,8-dihydro-5H-pyrano[4,3-b]pyridin-5-one,
4-methyl-3,4-dihydro-1H-pyrano[3,4-b]pyridin-1-one,
6-hydroxy-3,4-dihydro-1H-isochromen-1-one,
7-hydroxy-3,4-dihydro-2H-chromen-2-one,
3-ethyl-1H-isochromen-1-one, 3-(hydroxymethyl)-1H-isochromen-1-one,
9-hydroxy-1H,3H-benzo[de]isochromen-1-one,
6,7-dimethoxy-1,4-dihydro-3H-isochromen-3-one and
3-phenyl-3,4-dihydro-1H-isochromen-1-one, 7-membered-ring lactones,
such as E-caprolactone, 1,5-dioxepan-2-one, 5-methyloxepan-2-one,
oxepane-2,7-dione, thiepan-2-one, 5-chlorooxepan-2-one,
(4S)-4-(propan-2-yl)oxepan-2-one, 7-butyloxepan-2-one,
5-(4-aminobutyl)oxepan-2-one, 5-phenyloxepan-2-one,
7-hexyloxepan-2-one, (5S,7S)-5-methyl-7-(propan-2-yl)oxepan-2-one,
4-methyl-7-(propan-2-yl)oxepan-2-one, and lactones with higher
numbers of ring members, such as
(7E)-oxacycloheptadec-7-en-2-one.
[0166] Lactides are cyclic compounds containing two or more ester
bonds in the ring. Preferred compounds are glycolide
(1,4-dioxane-2,5-dione), L-lactide
(L-3,6-dimethyl-1,4-dioxane-2,5-dione), D-lactide, DL-lactide,
mesolactide and 3-methyl-1,4-dioxane-2,5-dione,
3-hexyl-6-methyl-1,4-dioxane-2,5-diones,
3,6-di(but-3-en-1-yl)-1,4-dioxane-2,5-dione (in each case inclusive
of optically active forms). L-lactide is particularly
preferred.
[0167] Cyclic carbonates used are preferably compounds having at
least three optionally substituted methylene groups between the
oxygen atoms of the carbonate group. Preferred compounds are
trimethylene carbonate, neopentyl glycol carbonate
(5,5-dimethyl-1,3-dioxan-2-one), 2,2,4-trimethyl-1,3-pentanediol
carbonate, 2,2-dimethyl-1,3-butanediol carbonate, 1,3-butanediol
carbonate, 2-methyl-1,3-propanediol carbonate, 2,4-pentanediol
carbonate, 2-methylbutane-1,3-diol carbonate, TMP monoallyl ether
carbonate, pentaerythritol diallyl ether carbonate,
5-(2-hydroxyethyl)-1,3-dioxan-2-one,
5-[2-(benzyloxy)ethyl]-1,3-dioxan-2-one,
4-ethyl-1,3-dioxolan-2-one, 1,3-dioxolan-2-one,
5-ethyl-5-methyl-1,3-dioxan-2-one, 5,5-diethyl-1,3-dioxan-2-one,
5-methyl-5-propyl-1,3-dioxan-2-one,
5-(phenylamino)-1,3-dioxan-2-one and 5,5-dipropyl-1,3-dioxan-2-one.
Particular preference is given to trimethylene carbonate and
neopentyl glycol carbonate.
[0168] Under the conditions of the process of the invention for the
copolymerization of alkylene oxides and CO.sub.2, cyclic carbonates
having fewer than three optionally substituted methylene groups
between the oxygen atoms of the carbonate group are incorporated
into the polymer chain not at all or only to a small extent.
[0169] However, cyclic carbonates having fewer than three
optionally substituted methylene groups between the oxygen atoms of
the carbonate group may be used together with other suspension
media. Preferred cyclic carbonates having fewer than three
optionally substituted methylene groups between the oxygen atoms of
the carbonate group are ethylene carbonate, propylene carbonate,
2,3-butanediol carbonate, 2,3-pentanediol carbonate,
2-methyl-1,2-propanediol carbonate and 2,3-dimethyl-2,3-butanediol
carbonate.
[0170] Cyclic anhydrides are cyclic compounds containing an
anhydride group in the ring. Preferred compounds are succinic
anhydride, maleic anhydride, phthalic anhydride,
cyclohexane-1,2-dicarboxylic anhydride, diphenic anhydride,
tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride,
norbornenedioic anhydride and chlorination products thereof,
succinic anhydride, glutaric anhydride, diglycolic anhydride,
1,8-naphthalic anhydride, succinic anhydride, dodecenylsuccinic
anhydride, tetradecenylsuccinic anhydride, hexadecenylsuccinic
anhydride, octadecenylsuccinic anhydride, 3- and 4-nitrophthalic
anhydride, tetrachlorophthalic anhydride, tetrabromophthalic
anhydride, itaconic anhydride, dimethylmaleic anhydride,
allylnorbornenedioic anhydride, 3-methylfuran-2,5-dione,
3-methyldihydrofuran-2,5-dione, dihydro-2H-pyran-2,6(3H)-dione,
1,4-dioxane-2,6-dione, 2H-pyran-2,4,6(3H,5H)-trione,
3-ethyldihydrofuran-2,5-dione, 3-methoxydihydrofuran-2,5-dione,
3-(prop-2-en-1-yl)dihydrofuran-2,5-dione,
N-(2,5-dioxotetrahydrofuran-3-yl)formamide and
3[(2E)-but-2-en-1-yl]dihydrofuran-2,5-dione. Particular preference
is given to succinic anhydride, maleic anhydride and phthalic
anhydride.
[0171] In one configuration of the process of the invention, the
molar ratio of the carbon-carbon double bonds in the
polyethercarbonate polyol to the Si--H bonds of the polysiloxane
compound is from 1:10 to 10:1, preferably from 1:5 to 5:1.
[0172] In one configuration of the process of the invention, the
catalyst (A) is a hydrosilylation catalyst.
[0173] The hydrosilylation of the polyether carbonate having
unsaturated groups can be induced particularly quickly and
effectively by the use of platinum and palladium catalysts in a
concentration of 1 to 5000 ppm, it being possible to employ
homogeneous and heterogeneous catalysts. Suitable catalysts are
specified in DE 102011076687. In the case of the homogeneous
catalysts, preference is given to Karstedt catalysts. These are
complexes of Pt(0) with compounds containing double bonds,
especially vinylsilanes such as tetramethyldivinyldisiloxane or
tetramethyltetravinylcyclotetrasiloxane. These are described, for
example, in the Patinium Metals Review (1997), 41(2), 66. In
addition, it is also possible to use Speier catalysts, i.e.
complexes of hexachloroplatinic acid with alcohols such as
isopropanol. More preferably, it is possible to use Karstedt
catalysts. The heterogeneous catalysts are preferably platinum
metals, more preferably platinum supported on inorganic supports or
charcoal, more preferably on charcoal. It is also possible to add
ligands to the heterogeneous catalysts, such as phosphines or
nitrogen heterocycles, as activators or co-catalysts. One method
for the hydrosilylation of alkene groups can be found, for example,
in F. Eckstorff, Y. Zhu, R. Maurer, T. E. Miller, S. Scholz, J. A.
Lercher, Polymer 52 (2011) 2492-2498.
[0174] In a preferred configuration of the process of the
invention, the hydrosilylation catalyst is one or more compound(s)
and is selected from the group consisting of Karstedt catalysts,
Speier catalysts, elemental platinum and elemental platinum on a
support of activated carbon or alumina.
[0175] In a preferred configuration of the process of the
invention, the hydrosilylation catalyst is one or more compound(s)
and is selected from the group consisting of
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane,
hexachloroplatinic acid,
pentamethylcyclopentadienyl-tris(acetonitrile)-ruthenium(II)
hexafluorophosphate, bis(1,5-cyclooctadiene)rhodium(I)
tetrafluoroborate, (bicyclo[2.2.1]hepta-2,5-diene)rhodium(I)
chloride dimer, tris(triphenylphosphine)rhodium(I) chloride,
benzenedichlororuthenium(II) dimer, dichloro(p-cymene)ruthenium(II)
dimer and
benzylidenebis(tricyclohexylphosphine)dichlororuthenium(II).
[0176] The invention further provides an organooxysilyl-crosslinked
polymer obtainable by the process of the invention, wherein the
organooxysilyl end group has a number-average molecular weight Mn
of .gtoreq.500 g/mol to .ltoreq.100 000 g/mol, more preferably
.gtoreq.1000 g/mol to .ltoreq.50 000 g/mol, which has been
determined by means of GPC. The procedure was according to DIN
55672-1: "Gel permeation chromatography, Part 1--Tetrahydrofuran as
eluent" (SECurity GPC System from PSS Polymer Service, flow rate
1.0 ml/min; columns: 2.times.PSS SDV linear M, 8.times.300 mm, 5
.mu.m; RID detector). Polystyrene samples of known molar mass were
used for calibration. Polydispersity was calculated as the ratio
Mw/Mn.
EXAMPLES
[0177] PET-1 difunctional poly(oxypropylene)polyol having an OH
number of 112 mg.sub.KOH/g
[0178] PO propylene oxide from Chemgas, purity>99%
[0179] AGE allyl glycidyl ether from Sigma Aldrich,
purity>99%
[0180] MA maleic anhydride from Sigma Aldrich, purity>99%
[0181] The DMC catalyst was prepared according to example 6 of WO-A
01/80994.
[0182] Polysiloxane Used [0183] Polysiloxane-1: polysiloxane from
Momentive, silane (Si--H) content 0.55 mmol/g; Mn of 900 g/mol
[0184] Polysiloxane-2:polysiloxane from Momentive, silane (Si--H)
content 3.80 mmol/g; Mn of 1280 g/mol
[0185] Catalysts Used
[0186] Karstedt catalyst (2.0% by weight of Pt in xylene) from
Sigma-Aldrich
[0187] Polyoxyalkylene Polyols Used
[0188] Preparation of a Difunctional Polyoxyalkylene Polyol
(Polyol-1) Containing Electron-Rich Double Bonds
[0189] A 970 ml pressure reactor equipped with a gas introduction
stirrer was charged with a mixture of DMC catalyst (48 mg) and
PET-1 (80 g) and this initial charge was stirred at 130.degree. C.
for 30 minutes under a partial vacuum (50 mbar), with argon being
passed through the reaction mixture. Following injection of 15 bar
of CO.sub.2, at which a slight drop in temperature was observed,
and following re-establishment of a temperature of 130.degree. C.,
8.0 g of a monomer mixture (16.7% by weight of allyl glycidyl ether
[corresponding to 9.3 mol %] in solution in propylene oxide) was
metered in by means of an HPLC pump (1 ml/min). The reaction
mixture was stirred (800 rpm) at 130.degree. C. for 20 min. The
addition of 8.0 g of the monomer mixture was repeated a second and
third time. After cooling to 100.degree. C., a further 136.0 g of
the monomer mixture (16.7% by weight of allyl glycidyl ether) was
metered in via an HPLC pump (1 ml/min), keeping the CO.sub.2
pressure constant at 15 bar. The reaction mixture was then stirred
at 100.degree. C. for a further 1 h. The reaction was halted by
cooling of the reactor with ice-water.
[0190] Characterization of the polyoxyalkylene polyol obtained by
the methods specified in WO 2015032737 A1 gave an OH number of 27.2
mg.sub.KOH/g, a CO.sub.2 content of 12.79% by weight, a molecular
weight M.sub.n of 4566 g/mol, a polydispersity index (PDI) of 1.33
and a double bond content of 2.2% by weight.
[0191] Preparation of a Difunctional Polyoxyalkylene Polyol
(Polyol-2) Containing Electron-Deficient Double Bonds
[0192] A 970 ml pressure reactor equipped with a gas introduction
stirrer was charged with a mixture of DMC catalyst (70 mg) and
PET-1 (80 g) and this initial charge was stirred at 130.degree. C.
for 30 minutes under a partial vacuum (50 mbar), with argon being
passed through the reaction mixture. Following injection of 15 bar
of CO.sub.2, at which a slight drop in temperature was observed,
and following re-establishment of a temperature of 130.degree. C.,
80 g of a monomer mixture (11.0% by weight of maleic anhydride
[corresponding to 6.8 mol %] in solution in propylene oxide) was
metered in by means of an HPLC pump (1 ml/min). The reaction
mixture was stirred (800 rpm) at 130.degree. C. for 20 min. The
addition of 8.0 g of the monomer mixture was repeated a second and
third time. After cooling to 100.degree. C., a further 246.0 g of
the monomer mixture (11.0% by weight of maleic anhydride in
solution in propylene oxide) was metered in via an HPLC pump (1
ml/min), keeping the CO.sub.2 pressure constant at 15 bar. The
reaction mixture was then stirred at 100.degree. C. for a further 1
h. The reaction was halted by cooling of the reactor with
ice-water.
[0193] Characterization of the polyoxyalkylene polyol obtained by
the methods specified in WO 2015032737 A1 gave an OH number of 22.4
mg.sub.KOH/g, a CO.sub.2 content of 15.92% by weight, a molecular
weight M.sub.n of 5009 g/mol, a PDI of 1.9 and a double bond
content of 2.2% by weight.
[0194] Methods:
[0195] For rheological determination of the gel point, a sample of
the polyethercarbonate polyol was admixed with a substoichiometric
amount of a polysiloxane and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane. Shear
characteristics were analyzed on a Physica MCR501 from Anton Paar
equipped with PP15 measurement system. The complex moduli G'
(storage modulus) and G'' (loss modulus) were determined in an
oscillation measurement at 90.degree. C. and a frequency of 1 Hz,
using a plate/plate configuration with a plate diameter of 15 mm, a
plate-to-plate distance of 1 mm, and a 10 percent deformation. The
gel point was defined as the juncture when the storage modulus and
loss modulus were equal.
[0196] For the rheological determination of the gel time, a sample
of the polyethercarbonate polyol was admixed with an equimolar
amount of a polyisocyanate (diisocyanate and/or triisocyanate) and
dibutyltin laurate (1% by weight). The complex moduli G'(storage
modulus) and G'' (loss modulus) were determined in an oscillation
measurement at 60.degree. C. and a frequency of 1 Hz, using a
plate/plate configuration with a plate diameter of 15 mm, a
plate-to-plate distance of 1 mm, and a 10 percent deformation. The
gel point was defined as the juncture at which storage modulus (G')
and loss modulus (G'') are equal (G'/G''=1). For determination of
the storage modulus (G') after 2 hours, the value of the storage
modulus attained at this time, measured in Pa, was read off.
[0197] For the rheological determination of the adhesion fracture
energy (bonding force), a sample of the prepolymer was applied to
the measurement plate of the rheometer. The breaking force (FN) and
elongation at break (d) were determined in a bonding force
measurement at 30.degree. C., using a plate-plate configuration
having a plate diameter of 15 mm and a plate-to-plate distance of
0.8 mm. The sample was first pressed at a compression force of 10
N. Subsequently, the upper plate was raised at a speed of -2.5 mm/s
and the breaking force (FN) was determined over the incremental
distances di until the sample broke. The adhesion fracture energy
was calculated by the following formula, where "r" is the radius of
the upper plate (r=7.5 mm), and is reported in N/mm.
E.sub.ad=.SIGMA..sub.i(F.sub.N,i.times.d.sub.i/.pi.)/(r.sup.2.times..pi.-
)
[0198] The infrared (IR) spectroscopy measurements were effected on
a Bruker Alpha-P FT-IR spectrometer; the measurements were effected
in pure substance; the wavenumber of the maximum of the signal for
the C=C stretch vibration is reported.
[0199] The double bond content of the prepolymers is found as the
quotient of the reported double bond content of the
polyethercarbonate polyols used (reported in C2H4 equivalents per
unit mass of polyethercarbonate polyol), based on the total mass of
the reactants used (polyethercarbonate polyol, isocyanate mixture,
catalyst), and is reported in C2H4 equivalents per unit mass of
prepolymer.
Example 1: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds and Polysiloxane-1 in a Molar Ratio of 4
Double Bonds (C.dbd.C):1 Silane (Si--H)
[0200] In a crimp-cap bottle, polysilane 1 (38 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane (19 mg) were
blended with one another (mixture 1).
[0201] In a weighing boat, polyol-1 (500 mg) and mixture 1 (380 mg)
were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 90.degree. C. over 120 min.
Example 2: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds (C.dbd.C) and Polysiloxane-2 in a Molar
Ratio of 4 Double Bonds:1 Silane (Si--H)
[0202] In a crimp-cap bottle, polysiloxane 2 (5.6 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane (19 mg) were
blended with one another (mixture 2).
[0203] In a weighing boat, polyol-1(500 mg) and mixture 2 (56 mg)
were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 90.degree. C. over 120 min.
Example 3 (Comp.): Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds and Sulfur in a Molar Ratio of 4 Double
Bonds (C.dbd.C):1 S.sub.8 Unit
[0204] In a weighing boat, polyol-1 (500 mg) and elemental sulfur
(50 mg) were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 90.degree. C. over 120 min.
[0205] Analysis by means of IR spectroscopy showed the
characteristic signal for double bonds at 1645 cm.sup.-1.
Example 4 (Comp.): Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds (C.dbd.C)
[0206] Polyol-1 (500 mg) supplemented with 60 ppm of catalyst was
applied to the measurement system of the rheometer and the curing
characteristics were monitored at 90.degree. C. over 120 min.
[0207] Analysis by means of IR spectroscopy showed the
characteristic signal for double bonds at 1645 cm.sup.-1.
TABLE-US-00001 TABLE 1 Molar G' Polyether- ratio of Gel after Ex-
carbonate (C.dbd.C) to point 2 h ample polyol Crosslinker
(Si--H).sup.a) [s] [Pa] 1 Polyol-1 Polysiloxane- 4:1 1230 3380 1 2
Polyol-1 Polysiloxane- 4:1 <60 4900 2 3 Polyol-1 Sulfur No
curing No curing 0 (comp.) 4 Polyol-1 -- No curing No curing 0
(comp.) Comp.: comparative example; .sup.a)molar ratio of the
carbon-carbon double bonds (C.dbd.C) in the polyethercarbonate
polyol to the Si--H bonds of the polysiloxane compound
[0208] Examples 1-4 show that the crosslinking of electron-rich
polyethercarbonate polyols with substoichiometrically of a
polysiloxane leads to the construction of a 3D network. In this
context, the reaction with siloxane-richer compounds (examples 1-2)
leads to a more stable network within a shorter time. It was not
possible to observe reaction with sulfur as crosslinker or without
any crosslinker. Without siloxane compounds, the polyol 1 does not
cure (comparative examples 3-4).
Example 5: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds and Polysiloxane-1 in a Molar Ratio of 2
Double Bonds (C.dbd.C):1 Silane (Si--H)
[0209] In a crimp-cap bottle, polysiloxane 1 (38 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane (9.5 mg) were
blended with one another (mixture 3).
[0210] In a weighing boat, polyol-1 (500 mg) and mixture 3 (760 mg)
were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 90.degree. C. over 120 min.
Example 6: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds and Polysiloxane-2 in a Molar Ratio of 2
Double Bonds (C.dbd.C):1 Silane (Si--H)
[0211] In a crimp-cap bottle, polysiloxane 2 (5.6 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane (9.5 mg) were
blended with one another (mixture 4).
[0212] In a weighing boat, polyol-1 (500 mg) and mixture 4 (120 mg)
were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 90.degree. C. over 120 min.
TABLE-US-00002 TABLE 2 Molar G' Polyether- ratio of Gel after Ex-
carbonate (C.dbd.C) to point 2 h ample polyol Crosslinker
(Si--H).sup.a) [s] [Pa] 5 Polyol-1 Poly siloxane- 2:1 <60 8800 1
6 Polyol-1 Poly siloxane- 2:1 <60 930 2 4 Polyol-1 -- No curing
No curing 0 (comp.) Comp.: comparative example; .sup.a)molar ratio
of the carbon-carbon double bonds (C.dbd.C) in the
polyethercarbonate polyol to the Si--H bonds of the polysiloxane
compound
[0213] Examples 5-6 show that the change in the ratio between
double bond and siloxane leads to a different network density and
reaction time. Given double the silane content, there is a
disproportionate rise in the stability of the network formed, while
there is a distinct fall in the reaction time.
Example 7: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds and Polysiloxane-1 in a Molar Ratio of 1
Double Bonds (C.dbd.C):1 Silane (Si--H)
[0214] In a crimp-cap bottle, polysiloxane 1 (38 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane (4.5 mg) were
blended with one another (mixture 5).
[0215] In a weighing boat, polyol-1(500 mg) and mixture 5 (1.52 g)
were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 90.degree. C. over 120 min.
Example 8: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-1) with 2.2% by
Weight of Double Bonds and Polysiloxane-2 in a Molar Ratio of 1
Double Bonds (C.dbd.C):1 Silane (Si--H)
[0216] In a crimp-cap bottle, polysiloxane 2 (5.6 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane (4.5 mg) were
blended with one another (mixture 6).
[0217] In a weighing boat, polyol-1 (500 mg) and mixture 6 (240 mg)
were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 90.degree. C. over 120 min.
TABLE-US-00003 TABLE 3 Molar G' Polyether- ratio of Gel after Ex-
carbonate (C.dbd.C) to point 2 h ample polyol Crosslinker
(Si--H).sup.a) [s] [Pa] 7 Polyol-1 Polysiloxane- 1:1 <60 19900 1
8 Polyol-1 Polysiloxane- 1:1 <60 2950 2 4 Polyol-1 -- No curing
No curing 0 (comp.) Comp.: comparative example; .sup.a)molar ratio
of the carbon-carbon double bonds (C.dbd.C) in the
polyethercarbonate polyol to the Si--H bonds of the polysiloxane
compound
[0218] Examples 7-8 show that the change in the ratio between
double bond and silane (Si--H) leads to a different network density
and reaction time. In the case of a stoichiometric silane content,
the stability of the network formed increases assumes a
maximum.
Example 9: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-2) with 2.2% by
Weight of Double Bonds and Polysiloxane-1 in a Molar Ratio of 1
Double Bonds (C.dbd.C):1 Silane
[0219] In a crimp-cap bottle, polysiloxane 1 (38 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane (4.5 mg) were
blended with one another (mixture 7).
[0220] In a weighing boat, polyol-2 (500 mg) and mixture 7 (1.52 g)
were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 140.degree. C. over 120 min.
Example 10: Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-2) with 2.2% by
Weight of Double Bonds and Polysiloxane-2 in a Molar Ratio of 1
Double Bonds (C.dbd.C):1 Silane
[0221] In a crimp-cap bottle, polysiloxane 2 (10.34 g) and
platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisioxane (29.21 mg)
were blended with one another (mixture 8).
[0222] In a weighing boat, polyol-2 (500 mg) and mixture 8 (103.4
mg) were mixed. Subsequently, the mixture was applied to the
measurement system of the rheometer and the curing characteristics
were monitored at 140.degree. C. over 120 min.
Example 11 (Comp.): Preparation of an Elastomer Precursor Using an
Unsaturated Polyethercarbonate Polyol (Polyol-2) with 2.2% by
Weight of Double Bonds
[0223] Polyol-2 (500 mg) was supplemented with 300 ppm of catalyst
and applied to the measurement system of the rheometer and the
curing characteristics were monitored at 140.degree. C. over 120
min.
[0224] Analysis by means of IR spectroscopy showed the
characteristic signal for double bonds at 1645 cm.sup.-1.
TABLE-US-00004 TABLE 4 Ratio of G' Polyether- (C.dbd.C) after Ex-
carbonate to Gel point 2 h ample polyol Crosslinker Si--H [s] [Pa]
9 Polyol-2 Polysiloxane- 1:1 150 217 1 10 Polyol-2 Polysiloxane-
1:1 6167 25.6 2 11 Polyol-2 -- No curing No curing 0 (comp.) Comp.:
comparative example
[0225] Examples 8-9 show the influence of the silane (Si--H)
content chosen on gel time and network density.
* * * * *