U.S. patent application number 17/040067 was filed with the patent office on 2021-01-21 for uretdione-containing polyurethane-dispersions comprising hydrophilic groups.
The applicant listed for this patent is Covestro Deutschland AG, Covestro LLC. Invention is credited to Saskia Beuck, Sebastian Doerr, Dorota Greszta-Franz, Hans-Josef Laas, Nusret Yuva.
Application Number | 20210017322 17/040067 |
Document ID | / |
Family ID | 1000005123547 |
Filed Date | 2021-01-21 |
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United States Patent
Application |
20210017322 |
Kind Code |
A1 |
Beuck; Saskia ; et
al. |
January 21, 2021 |
URETDIONE-CONTAINING POLYURETHANE-DISPERSIONS COMPRISING
HYDROPHILIC GROUPS
Abstract
The present invention relates to a specific uretdione
prepolymer, and an aqueous curable composition based on the
specific uretdione prepolymer. Furthermore, it pertains to a
process for curing said aqueous curable composition, the cured
article obtained by this process and additionally to the use of
said aqueous composition for coatings, adhesives and/or
sealants.
Inventors: |
Beuck; Saskia; (Leverkusen,
DE) ; Doerr; Sebastian; (Dusseldorf, DE) ;
Laas; Hans-Josef; (Odenthal, DE) ; Greszta-Franz;
Dorota; (Solingen, DE) ; Yuva; Nusret;
(Burscheid, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Covestro Deutschland AG
Covestro LLC |
Leverkusen
Pittsburgh |
PA |
DE
US |
|
|
Family ID: |
1000005123547 |
Appl. No.: |
17/040067 |
Filed: |
March 21, 2019 |
PCT Filed: |
March 21, 2019 |
PCT NO: |
PCT/EP2019/057068 |
371 Date: |
September 22, 2020 |
Related U.S. Patent Documents
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Application
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Patent Number |
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15933553 |
Mar 23, 2018 |
10633477 |
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17040067 |
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15933527 |
Mar 23, 2018 |
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15933507 |
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15933527 |
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15933495 |
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15933507 |
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15933570 |
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10731051 |
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15933495 |
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15933487 |
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15933570 |
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15933500 |
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10696775 |
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15933487 |
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15933470 |
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15933500 |
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15933511 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G 18/622 20130101;
C08G 18/2027 20130101; C08G 18/2036 20130101; C08G 18/4277
20130101; C09D 175/02 20130101; C08G 18/44 20130101; C08G 18/798
20130101; C09D 175/04 20130101; C08G 18/48 20130101; C09J 175/04
20130101; C08G 18/4236 20130101; C08G 18/6229 20130101; C08G 18/027
20130101; C08K 2201/012 20130101; C08G 18/1858 20130101; C09J
175/02 20130101; C08K 5/29 20130101; C08G 18/2063 20130101; C08G
2190/00 20130101 |
International
Class: |
C08G 18/02 20060101
C08G018/02; C08K 5/29 20060101 C08K005/29; C08G 18/48 20060101
C08G018/48; C08G 18/62 20060101 C08G018/62; C08G 18/44 20060101
C08G018/44; C08G 18/20 20060101 C08G018/20; C08G 18/42 20060101
C08G018/42; C09D 175/04 20060101 C09D175/04; C08G 18/18 20060101
C08G018/18; C08G 18/79 20060101 C08G018/79; C09J 175/04 20060101
C09J175/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2018 |
EP |
18163620.0 |
Mar 23, 2018 |
EP |
18163621.8 |
Mar 23, 2018 |
EP |
18163625.9 |
Jul 5, 2018 |
EP |
18181876.6 |
Jul 5, 2018 |
EP |
18181877.4 |
Claims
1. A uretdione prepolymer, which comprises at least one uretdione
group, and which is obtained by reacting A1) at least one uretdione
polyisocyanate having an isocyanate functionality of at least 2.0,
wherein said uretdione polyisocyanate is obtained from at least one
aliphatic polyisocyanate, with A2) at least one polyalkoxy ether
derivative comprising at least two --OH groups, which are present
on two different non neighboring atoms of the molecule and wherein
at least one of the --OH groups is not a terminal --OH group, and
A3) at least one reactant, which comprises at least one
Zerewitinoff-active group and being different from A2 or which is
H.sub.2O, in the presence of at least one catalyst, to obtain the
uretdione prepolymer, wherein the prepolymer has an acid number of
at most 4 mg KOH/g.
2. The uretdione prepolymer according to claim 1, wherein in a
first step, the at least one uretdione polyisocyanate A1 is
reacted, with the at least one polyalkoxy ether derivative A2 and
in a second step the polymer obtained in the first step is reacted
with the at least one reactant A3.
3. The uretdione prepolymer according to claim 1, wherein
components A1 to A3 are reacted in a one-step process.
4. The uretdione prepolymer according to claim 1, wherein in a
first step, the at least one uretdione polyisocyanate A1 is reacted
with the at least one reactant A3 and in a second step the polymer
obtained in the first step is reacted in a second step with the at
least one polyalkoxy ether derivative A2.
5. The uretdione prepolymer according to claim 1, where-in said
uretdione prepolymer is a nonionic prepolymer.
6. The uretdione prepolymer according to claim 1, wherein said
uretdione prepolymer exhibits a zeta potential of at least -20
mV.
7. The uretdione prepolymer according to claim 1, wherein said
uretdione polyisocyanate A1 is obtained from at least one
cycloaliphatic polyisocyanate.
8. The uretdione prepolymer according to claim 1, wherein said
uretdione polyisocyanate A1 is prepared from isophorone
diisocyanate as the only polyisocyanate.
9. The uretdione prepolymer according to claim 1, wherein compound
A2 is selected from compounds of formula (I): ##STR00006## wherein,
X is H or alkyl; R is a C.sub.1-4 alkylene group; p is an integer
of 2 to 50; in each unit p n is independently 0 or 1 and m is
independently 0 or 1, with the proviso that at least one of n or m
in each unit p is 1.
10. The uretdione prepolymer according to claim 1, wherein compound
A3 is selected from the group consisting of at least one polyol,
which is different from A2, from polyester polyols, polyether
polyols, polyurethane polyols, polyacrylate polyols,
polymethacrylate polyols, polycarbonate polyols, and mixtures
thereof.
11. An aqueous, curable composition, comprising: the uretdione
prepolymer according to claim 1, and optionally, at least one
compound, which comprises at least one Zerewitinoff-active group
and/or optionally, at least one azolate-compound.
12. The aqueous, curable composition according to claim 11, wherein
said uretdione prepolymer is contained in a total amount of 3 to 40
wt. %, based on the total weight of the composition.
13. The aqueous, curable composition according to claim 11, wherein
said azolate-compound is selected from the group consisting of at
least one triazolate-compound of formula (III) or salts thereof and
formula (IV) or salts thereof ##STR00007## wherein, R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 are independently selected from a
hydrogen atom, a halogen atom, a nitro group, a saturated or
unsaturated, aliphatic or cycloaliphatic radical, an optionally
substituted aromatic group comprising up to 20 carbon atoms and
optionally, up to 3 heteroatoms selected from oxygen, sulfur, and
nitrogen, an optionally substituted araliphatic group comprising up
to 20 carbon atoms and optionally, up to 3 heteroatoms selected
from oxygen, sulfur, and nitrogen, and wherein R.sup.3 and R.sup.4
of formula (IV) together with the carbon atoms of the
1,2,3-triazolate five-membered ring form fused rings with 3 to 6
carbon atoms.
14. The aqueous, curable composition according to claim 13, wherein
said azolate-compound is selected from the group consisting of
alkaline metal-1,2,4-triazolate, alkaline metal-1,2,3-triazolate,
alkaline metal-benzotriazolate, alkaline earth
metal-1,2,4-triazolate, alkaline earth metal-1,2,3-triazolate, and
alkaline earth metal-benzotriazolate.
15. The aqueous, curable composition according to claim 11, wherein
said at least one compound, which comprises at least one
Zerewitinoff-active group is selected from the group consisting of
polyester polyols, polyether polyols, polyurethane polyols,
polyacrylate polyols, polymethacrylate polyols, polycarbonate
polyols, and mixtures thereof.
16. The aqueous, curable composition according to claim 11, wherein
said uretdione prepolymer is contained in an amount of 1 to 50 wt.
% or said at least one compound, which comprises at least one
Zerewitinoff-active group is contained in an amount of 0 to 80
wt.-% or said triazolate-compound is contained in an amount of 0.1
to 10 wt. %, based on the total weight of the composition,
respectively.
17. A process for curing a liquid composition on a substrate,
comprising a) applying on a substrate an aqueous, curable
composition according to claim 11; and a) exposing the aqueous,
curable composition to a temperature of 60.degree. C. to
160.degree. C. to cure said composition.
18. The cured article obtained by the process according to claim
17.
19. In a process for the production of one of a coating, an
adhesive and a sealant, the improvement comprising including the
composition according to claim 11.
Description
[0001] The present invention relates to a specific uretdione
prepolymer, and an aqueous curable composition based on the
specific uretdione prepolymer. Furthermore, it pertains to a
process for curing said aqueous curable composition, the cured
article obtained by this process and additionally to the use of
said aqueous composition for coatings, adhesives and/or
sealants.
[0002] Aqueous curable compositions based on specific uretdione
prepolymers are for example known from DE 10 2005 036 654 A1.
However, those compositions do not show a sufficient long-term
stability. The hydrophilization of the polymer is obtained via
ionogenic groups.
[0003] Therefore, it was an object of the present invention to
provide an uretdione prepolymer, which provides an improved aqueous
curable composition, which shows improved, preferably long-term,
storage stability.
[0004] It has been surprisingly found by the present inventors that
following uretdione prepolymer can overcome the above-mentioned
deficiency:
[0005] An uretdione prepolymer, which comprises at least one
uretdione group, and which is obtainable by reacting
[0006] A1) at least one uretdione polyisocyanate having an
isocyanate functionality of at least 2.0, whereby said uretdione
polyisocyanate is obtained from at least one aliphatic
polyisocyanate, with
[0007] A2) at least one polyalkoxy ether derivative comprising at
least two --OH groups, which are present on two different
non-neighbouring atoms of the molecule and whereby at least one of
the --OH groups is not a terminal --OH group, and
[0008] A3) at least one reactant, which comprises at least one
Zerewitinoff-active group and being different from A2 or which is
H.sub.2O,
[0009] preferably in the presence of at least one catalyst, to
obtain the uretdione prepolymer;
[0010] wherein the prepolymer has an acid number of at most 4 mg
KOH/g, preferably determined according to DIN EN ISO 2114:2002-06
as 37 wt. % aqueous dispersion.
[0011] When the uretdione prepolymer of the present invention is
employed in aqueous curable compositions, the thus obtained
compositions are homogenous after storage over a long time, can
retain a high amount of uretdione groups, compared to the initially
used ones, the uretdione groups can be reacted with alcohols or
amines, whereby a crosslinking of the prepolymers is obtained, the
reaction of the uretdione group with alcohol can be catalysed and
the cured product obtained by these compositions show equivalent or
even improved lacquer properties. Not to be bound by any theory it
is assumed that the use of compounds A2 in the preparation of the
prepolymer leads to this properties, since it promotes chain growth
and provides a better cross-linking
[0012] In the present invention, any numerical range recited herein
is intended to include all sub-ranges subsumed therein. For
example, a range of "1 to 10" is intended to include all sub-ranges
between (and including) the recited minimum value of 1 and the
recited maximum value of 10, that is, having a minimum value equal
to or greater than 1 and a maximum value of equal to or less than
10.
[0013] In the present invention, a "monomer" is a low-molecular
weight compound comprising functional moieties, wherein said
monomer functions as a building block for polymers and has a
defined molecular weight.
[0014] In the present invention the term "polymer" refers to a
compound, formed during a chemical reaction by linking several
monomers (i.e. more than two monomers) of the same or different
kind together via covalent bonding, wherein the resulting polymer
can differ in its degree of polymerization, molecular weight
distribution and chain length respectively. Hence, a polymer
according to the present invention is a compound, comprising in its
molecular structure at least one repeating unit, which was
integrated in the polymer structure during polymer synthesis by
repeatedly linking monomers together via covalent bonds to form
said polymer structure. The number average molecular weight is
preferably at least 250 g/mol, more preferably at least 1,000
g/mol.
[0015] The term "polymer" includes homopolymers, copolymers,
block-copolymers and oligomers.
[0016] In the present invention, a "prepolymer" is a polymer with
reactive groups. In analogy to the definition of the term
"polymer", the molecular structure of a prepolymer is formed by
repeatedly linking more than two monomers of the same of different
kind together. The prepolymer can participate in a subsequent
formation of a polymer, which has a higher molecular weight than
said prepolymer. The term "prepolymer" encompasses polymers, which
are able to chemically react via at least one of its reactive
groups, forming a repeating unit of a (preferably crosslinked)
polymer. Therefore the term "prepolymer" encompasses as well
self-crosslinking polymers with at least two different kinds of
reactive groups, wherein said groups are able to chemically react
among themselves, so that the prepolymer molecules are able to
crosslink.
[0017] According to this invention, if not otherwise specified, the
average molecular weight is defined as the number average molecular
weight Mn. As molecular weight of polymers the number average
molecular weight Mn is applied. Mn is determined via gel permeation
chromatography (GPC at 23.degree. C.) in tetrahydrofurane as the
solvent. The measurement is performed as described in DIN 55672-1
(the DIN-version used was at the application date (or priority date
if applicable) of the present invention, the latest version):
"Gelpermeationschromatographie, Teil 1--Tetrahydrofuran als
Elutionsmittel" (SECurity GPC-System from PSS Polymer Service,
flowrate 1.0 ml/min; columns: 2.times.PSS SDV linear M, 8.times.300
mm, 5 .mu.m; RID-detector). Samples of polystyrene standards of
known molecular weight were used for calibration. The calculation
of the number average molecular weight was performed by software.
Baseline values and evaluation threshold values were determined
according to above referenced DIN 55672 Teil 1.
[0018] The term "low-molecular" is defined to encompass a molecular
weight up to 800 g/mol.
[0019] The term "high-molecular" is defined to encompass a
molecular weight above 800 g/mol.
[0020] An "organic compound" contains at least one moiety,
comprising a carbon-hydrogen covalent bond.
[0021] According to this application the term "aliphatic" is
defined as non-aromatic hydrocarbyl groups being saturated or
unsaturated.
[0022] According to this application the term "araliphatic" is
defined as hydrocarbyl moieties composed of a non-aromatic, as well
as saturated or unsaturated hydrocarbyl group, which is directly
bonded to an aromatic moiety.
[0023] According to this application the term "alicyclic" or
"cycloaliphatic" are optionally substituted, carbocyclic or
heterocyclic compounds or moieties, which are non-aromatic (like
for example cycloalkanes, cycloalkenes or oxa-, thia-, aza- or
thiazacycloalkanes). Particular examples are cyclohexyl groups,
cyclopentyl groups, and their N- or O-heterocyclic derivatives like
for example pyrimidine, pyrazine, tetrahydropyrane or
tetrahydrofurane.
[0024] In case the groups or compounds are disclosed to be
"optionally substituted" or "substituted", suitable substituents
are --F, --Cl, --I, --Br, --OH, --OCH.sub.3, --OCH.sub.2CH.sub.3,
--O-Isopropyl or --O-nPropyl, --OCF.sub.3, --CF.sub.3,
--S--C.sub.1-6-Alkyl and/or (optionally via a hetero atom attached)
a linear or branched, aliphatic and/or alicyclic structural unit
with 1 to 12 carbon atoms, respectively functioning as a substitute
for a carbon bound hydrogen atom of the molecule in question.
Preferred substituents are halogen (especially --F, --Cl),
C.sub.1-6-Alkoxy (especially methoxy and ethoxy), hydroxy,
trifluoromethyl and trifluoromethoxy, respectively functioning as a
substitute for a carbon bound hydrogen atom of the molecule in
question.
[0025] In a formula illustrating the structure of a chemical
moiety, a covalent bond of said formula marked with a * defines the
covalent bond, which connects said illustrated moiety to the rest
of a more complex molecular structure.
[0026] The term "transparent" preferably means that the coating
(with a thickness of 45 .mu.m) is capable of transmitting rays of
visible light so bodies situated beyond or behind can be distinctly
seen. Transparent coatings according to this invention exhibit a
Haze-value<20 (Haze measurement instrument: DIN EN ISO 2813 (the
DIN-version used at the application date (or at the priority date
if applicable) of the present invention at the latest version).
[0027] The present invention in particular pertains to: [0028] 1.
An uretdione prepolymer, which comprises at least one uretdione
group, and which is obtainable by reacting [0029] A1) at least one
uretdione polyisocyanate having an isocyanate functionality of at
least 2.0, whereby said uretdione polyisocyanate is obtained from
at least one aliphatic polyisocyanate, with [0030] A2) at least one
polyalkoxy ether derivative comprising at least two --OH groups,
which are present on two different non-neighbouring atoms of the
molecule and whereby at least one of the --OH groups is not a
terminal --OH group, and [0031] A3) at least one reactant, which
comprises at least one Zerewitinoff-active group and being
different from A2 or which is H.sub.2O, [0032] preferably in the
presence of at least one catalyst, to obtain the uretdione
prepolymer; [0033] wherein the prepolymer has an acid number of at
most 4 mg KOH/g, preferably determined according to DIN EN ISO
2114:2002-06 as 37 wt. % aqueous dispersion. [0034] 2. The
uretdione prepolymer according to aspect 1, characterized in that
[0035] in a first step, the at least one uretdione polyisocyanate
A1 is reacted, preferably in the presence of a catalyst, with the
at least one polyalkoxy ether derivative A2, wherein after the
first step the resulting intermediate product has preferably an
isocyanate content of 0.5 to 10 wt.-%, preferably 1 to 6 wt.-%,
more preferably 2 to 4 wt.-%, measured according to DIN EN ISO
11909:2007-05; [0036] and in a second step the polymer obtained in
the first step is reacted with the at least one reactant A3. [0037]
3. The uretdione prepolymer according to aspect 1, characterized in
that the components A1 to A3 are reacted in a one-step process,
preferably in the presence of a catalyst. [0038] 4. The uretdione
prepolymer according to aspect 1, characterized in that [0039] in a
first step, the at least one uretdione polyisocyanate A1 is reacted
with the at least one reactant A3 and in a second step the polymer
obtained in the first step is reacted in a second step with the at
least one polyalkoxy ether derivative A2, preferably in the
presence of a catalyst. [0040] 5. The uretdione prepolymer
according to any one of the above aspects, characterized in that
said uretdione prepolymer is a nonionic prepolymer. [0041] 6. The
uretdione prepolymer according to any one of the above aspects,
characterized in that said uretdione prepolymer exhibits a zeta
potential of at least -20 mV. [0042] 7. The uretdione prepolymer
according to any one of the above aspects, characterized in that
said uretdione prepolymer comprises at least one
*--O--(CH.sub.2CH.sub.2O).sub.n--R moiety, in which R is a hydrogen
atom or a (C.sub.1-C.sub.4)-alkyl group and n is a number from 3 to
100. [0043] 8. The uretdione prepolymer according to any one of the
above aspects, characterized in that said uretdione polyisocyanate
A1 is obtained from at least one cycloaliphatic polyisocyanate.
[0044] 9. The uretdione prepolymer according to any one of the
above aspects, characterized in that said uretdione polyisocyanate
A1 is obtained from isophorone diisocyanate (IPDI),
1,6-diisocyanatohexane (HDI) or mixtures thereof. [0045] 10. The
uretdione prepolymer according to any one of the above aspects,
characterized in that said uretdione polyisocyanate A1 is prepared
from at least 20 mol % isophorone diisocyanate (IPDI) based on the
total amount of polyisocyanates used. [0046] 11. The uretdione
prepolymer according to any one of the above aspects, characterized
in that said uretdione polyisocyanate A1 is prepared from
isophorone diisocyanate as the only polyisocyanate used. [0047] 12.
The uretdione prepolymer according to any one of the above aspects,
characterized in that the uretdione polyisocyanate A1 contains from
1 to 10 uretdione moieties. [0048] 13. The uretdione prepolymer
according to any one of the above aspects, characterized in that
compound A2 is selected from compounds of formula (I):
[0048] ##STR00001## [0049] characterized in that [0050] X is H or
alkyl, preferably H or C.sub.1-20-alkyl, more preferably H or
C.sub.2-10-alkyl; [0051] R is a C.sub.1-4 alkylene group; [0052] p
is an integer of 2 to 50; [0053] in each unit p [0054] n is
independently 0 or 1 and [0055] m is independently 0 or 1, [0056]
with the proviso that at least one of n or m in each unit p is 1;
[0057] preferably characterized in that [0058] X is H, methyl,
ethyl, or propyl, preferably ethyl; [0059] R is methyl; [0060] is
an integer of 5 to 25; [0061] in each unit p [0062] n is
independently 0 or 1 and [0063] m is independently 0 or 1, [0064]
with the proviso that at least one of n or m in each unit p is 1
and the total amount of n.gtoreq.m, preferably the total amount of
n is at least 2*m, more preferably n is at least 3*m, most
preferably only n is present. [0065] 14. The uretdione prepolymer
according to any one of the above aspects, characterized in that
compounds A3 is selected from at least one polyol which is
different from A2, preferably selected from polyester polyols,
polyether polyols, polyurethane polyols, polyacrylate polyols,
polymethacrylate polyols, polycarbonate polyols or mixtures
thereof, preferably A3 is selected from polyester polyols,
polyether polyols, polycarbonate polyols, polyurethane polyols,
polyacrylate polyols, polymethacrylate polyols,
C.sub.2-C.sub.10-hydrocarbons with at least two hydroxyl groups, or
mixtures thereof, most preferably A3 is a polyester polyol. [0066]
15. The uretdione prepolymer according to any one of the above
aspects, characterized in that said compound A1 is used in an
amount of 3.0 to 50.0 wt. % based on the total weight of compounds
A1 to A3. [0067] 16. The uretdione prepolymer according to any one
of the above aspects, characterized in that said compound A2 is
used in amount of 50 to 97 wt.-% based on the total weight of
compounds A1 to A3. [0068] 17. The uretdione prepolymer according
to any one of the above aspects, characterized in that the weight
ratio of A1 to A2 is from 1:1 to 1:32.3. [0069] 18. An aqueous,
curable composition, comprising or consisting of [0070] the
uretdione prepolymer according to any one of aspects 1 to 17, and
[0071] optionally at least one compound, which comprises at least
one Zerewitinoff-active group and/or [0072] optionally at least one
azolate-compound. [0073] 19. The aqueous, curable composition
according to aspect 18, characterized in that said uretdione
prepolymer is a dispersed uretdione prepolymer, preferably
characterized in that the uretdione prepolymer is suspended in the
aqueous liquid. [0074] 20. The aqueous, curable composition
according to aspect 18 or 19, characterized in that said uretdione
prepolymer is contained in a total amount of 3 to 40 wt. % based on
the total weight of the composition. [0075] 21. The aqueous,
curable composition according to any one of aspects 18 to 20,
characterized in that said composition is substantially free of
compounds comprising at least one isocyanate moiety. [0076] 22. The
aqueous, curable composition according to any one of aspects 18 to
21, characterized in that said azolate-compound is selected from at
least one triazolate-compound of formula (III) or salts thereof and
formula (IV) or salts thereof
[0076] ##STR00002## [0077] characterized in that [0078] R.sup.1,
R.sup.2, R.sup.3 and R.sup.4 are independently selected from a
hydrogen atom, a halogen atom, a nitro group, a saturated or
unsaturated, aliphatic or cycloaliphatic radical, an optionally
substituted aromatic group comprising up to 20 carbon atoms and
optionally up to 3 heteroatoms selected from oxygen, sulphur,
nitrogen, an optionally substituted araliphatic group comprising up
to 20 carbon atoms and optionally up to 3 heteroatoms selected from
oxygen, sulphur, nitrogen, and whereby R.sup.3 and R.sup.4 of
formula (IV) together with the carbon atoms of the 1,2,3-triazolate
five-membered ring form fused rings with 3 to 6 carbon atoms.
[0079] 23. The aqueous, curable composition according to aspect 22,
characterized in that said azolate-compound is selected from
alkaline metal-1,2,4-triazolate, alkaline metal-1,2,3-triazolate,
alkaline metal-benzotriazolate, alkaline earth
metal-1,2,4-triazolate, alkaline earth metal-1,2,3-triazolate,
alkaline earth metal-benzotriazolate. [0080] 24. The aqueous,
curable composition according to any one of aspects 18 to 23,
characterized in that said at least one compound, which comprises
at least one Zerewitinoff-active group is selected from polyester
polyols, polyether polyols, polyurethane polyols, polyacrylate
polyols, polymethacrylate polyols, or polycarbonate polyols and
mixtures thereof. [0081] 25. The aqueous, curable composition
according to any one of aspects 18 to 24, characterized in that
said uretdione prepolymer is contained in an amount of 1 to 50 wt.
% and/or [0082] said at least one compound, which comprises at
least one Zerewitinoff-active group is contained in an amount of 0
to 80 wt.-% and/or [0083] said triazolate-compound is contained in
an amount of 0.1 to 10 wt. %, based on the total weight of the
composition, respectively. [0084] 26. The aqueous, curable
composition according to any one of aspects 18 to 25, characterized
in that the composition comprises water in an amount of 10 to 85
wt. %, based on the total weight of the composition. [0085] 27. The
aqueous, curable composition according to any one of aspects 18 to
26, characterized in that the pH-value at 20.degree. C. is from pH
5 to pH 13. [0086] 28. Process for curing a liquid composition on a
substrate, comprising [0087] a) applying on a substrate an aqueous,
curable composition according to any one of aspects 18 to 27; and
[0088] a) exposing the deposited aqueous, curable composition to a
temperature of 60.degree. C. to 160.degree. C. to cure said
deposited curing composition. [0089] 29. A cured article obtainable
by the process according to aspect 28. [0090] 30. Use of the
composition according to any one of aspects 18 to 27 for coatings,
adhesives and/or sealants.
[0091] Suitable uretdione polyisocyanates A1 are typically obtained
by catalytic dimerization of polyisocyanates by methods which are
known in the art. Examples of suitable polyisocyanates include
diisocyanates such as linear aliphatic polyisocyanates,
cycloaliphatic polyisocyanates and alkaryl polyisocyanates.
Specific examples include 1,4-diisocyanatobutane,
1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2,4'-
and/or 4,4'-diisocyanatocyclohexylmethane (HMDI), isophorone
diisocyanate (IPDI), 1,3- and 1,4-bisisocyanatomethylcyclohexane,
1,3- and 1,4-xylylene diisocyanates (XDI) and mixtures thereof.
[0092] Examples of dimerization catalysts are: trialkylphosphines,
aminophosphines and aminopyridines such as dimethylaminopyridines,
and tris(dimethylamino)phosphine, as well as any other dimerization
catalyst known to those skilled in the art. The result of the
dimerization reaction depends, in a manner known to the skilled
person, on the catalyst used, on the process conditions and on the
polyisocyanates employed. In particular it is possible for products
to be formed which contain on average more than one uretdione group
per molecule, the number of uretdione groups being subject to a
distribution.
[0093] The uretdione polyisocyanate A1 preferably on average
contains from 1 to 10 uretdione moieties.
[0094] Preferably said uretdione polyisocyanate A1 is prepared from
at least one cycloaliphatic polyisocyanate. In another preferred
embodiment, said uretdione polyisocyanate A1 is prepared from at
least 20 mol % isophorone diisocyanate (IPDI) based on the total
amount of polyisocyanates used. Said uretdione polyisocyanate A1 is
most preferred prepared from isophorone diisocyanate as the only
polyisocyanate used. Alternatively the uretdione polyisocyanate A1
is preferably prepared from isophorone diisocyanate (IPDI),
1,6-diisocyanatohexane (HDI) or mixtures thereof.
[0095] Preferred uretdione polyisocyanates are for example
commercially available as Desmodur N3400 from Covestro Deutschland
AG, Leverkusen, Germany.
[0096] Component A2 is at least one polyalkoxy ether derivative
comprising at least two --OH groups, which are present on two
different non-neighbouring atoms of the molecule and whereby at
least one of the --OH groups is not a terminal --OH group.
Preferred embodiments are defined in formula (I) above.
[0097] Preferred commercially available examples are Ymer.TM. N120
(CAS number: 131483-27-7) by Perstorp Holding AB, Malmo, Sweden and
Tegomer.RTM. D 3403 (Evonik Industries AG, Essen, DE).
[0098] Component A3 is at least one reactant, which comprises at
least one Zerewitinoff-active group and being different from A2 or
H.sub.2O; preferably at least one Zerewitinoff-active group and
being different from A2.
[0099] A "Zerewitinoff-active group" is defined as a functional
group, comprising at least one Zerewitinoff-active hydrogen atom,
being an acidic hydrogen atom or active hydrogen atom. The
abundance of such an active hydrogen atom is determined by a known
reaction of the compound in question with a Grignard reagent. The
amount of Zerewitinoff-active hydrogen atoms is typically
determined by measuring the amount of released methane gas, and
subsequently calculated in consideration of the stoichiometry of
the following reaction equation, wherein for each mole of active
hydrogen atoms of the compound in question (R--XH) one mole of
methyl magnesium bromide (CH.sub.3--MgBr) is used and one mole of
methane is released:
CH.sub.3--MgBr+R--XH.fwdarw.CH.sub.4+MG (XR)Br
[0100] Zerewitinoff-active groups are in particular C--H active
organic groups, --OH, --SH, --NH.sub.2 or --NHR' wherein R' denotes
an organic moiety. Preferably Zerewitinoff-active groups are
selected from --OH, --SH, --NH.sub.2 or --NHR' wherein R' denotes
an organic moiety. Especially preferred, the Zerewitinoff-active
groups according to the invention are --OH. A particularly
preferred uretdione prepolymer as component A+B) comprises as
Zerewitinoff-active groups at least two hydroxy groups.
[0101] It was also found, that the curing time was improved by
introducing hydrophilic groups as grafts or terminus into the
structure of said uretdione prepolymer. It is preferred, when said
hydrophilic groups do not comprise an ionic moiety. A preferred
uretdione prepolymer comprises grafts with at least one hydrophilic
group selected from polyoxyalkylene ether capped with methyl,
ethyl, propyl or butyl, polyethyleneoxide capped with one methyl
group, Polyethyleneoxide capped with one ethyl, propyl, or butyl
group. Particularly preferred uretdione prepolymers comprise
additionally on average at least one
*--O--(CH.sub.2CH.sub.2O).sub.n--R moiety, in which R denotes a
(C.sub.1-C.sub.4)-alkyl group and n denotes a number from 3 to 100.
n denotes preferably a number from 5 to 70, more preferably from 7
to 55. R is preferably a methyl group.
[0102] Said hydrophilic groups are introduced into the structure of
said uretdione prepolymer by (preferably nonionic) hydrophilizing
agents. Suitable nonionically hydrophilizing agents are, for
example, polyoxyalkylene ethers which have isocyanate-reactive
groups, such as hydroxy, amino or thiol groups. A preference is
given to monohydroxy-functional polyalkylene oxide polyether
alcohols having, on statistical average, 5 to 70, preferably 7 to
55, ethylene oxide units per molecule, as are accessible in a
manner known per se by alkoxylation of suitable starter molecules
(e.g. in Ullmanns Encyclopadie der technischen Chemie [Ullmanns
encyclopaedia of industrial chemistry], 4th edition, Volume 19,
Verlag Chemie, Weinheim pp. 31-38). These are either pure
polyethylene oxide ethers or mixed polyalkylene oxide ethers, where
they contain at least 30 mol %, preferably at least 40 mol %,
ethylene oxide units, based on all of the alkylene oxide units
present.
[0103] Suitable starter molecules for such nonionic hydrophilizing
agents are in particular saturated monoalcohols, such as methanol,
ethanol, n-propanol, isopropanol, n-butanol, isobutanol,
sec-butanol, the isomeric pentanols, hexanols, octanols and
nonanols, n-decanol, n-dodecanol, n-tetradecanol, n-hexadecanol,
n-octadecanol, cyclohexanol, the isomeric methylcyclohexanols or
hydroxymethylcyclohexane, 3-ethyl-3-hydroxymethyloxetane or
tetrahydrofurfuryl alcohol, diethylene glycol monoalkyl ethers,
such as, for example, diethylene glycol monobutyl ether,
unsaturated alcohols, such as allyl alcohol, 1,1-dimethylallyl
alcohol or oleyl alcohol, aromatic alcohols, such as phenol, the
isomeric cresols or methoxyphenols, araliphatic alcohols, such as
benzyl alcohol, anisyl alcohol or cinnamyl alcohol, secondary
monoamines, such as dimethylamine, diethylamine, dipropylamine,
diisopropylamine, dibutylamine, bis(2-ethylhexyl)amine, N-methyl-
and N-ethylcyclohexylamine or dicyclohexylamine, and also
heterocyclic secondary amines, such as morpholine, pyrrolidine,
piperidine or 1H-pyrazole. Preferred starter molecules are
saturated monoalcohols of the type specified above. Particular
preference is given to using diethylene glycol monobutyl ether or
n-butanol as starter molecules.
[0104] Alkylene oxides suitable for the alkoxylation reaction are
in particular ethylene oxide and propylene oxide, which can be used
in the alkoxylation reaction in any desired order or else in a
mixture.
[0105] Particularly preferred nonionic hydrophilizing agents are
monofunctional mixed polyalkylene oxide polyethers, which have 40
to 100 mol % ethylene oxide units and 0 to 60 mol % propylene oxide
units.
[0106] Suitable polyol as compound A3 is preferred selected from
polyester polyol, polyether polyol, polyurethane polyol,
polycarbonate polyol, polyacrylate polyol, polymethacrylate polyol,
C.sub.2-C.sub.10-hydrocarbon with at least two hydroxyl groups, or
mixtures thereof.
[0107] The term "polyol" includes materials having an average of
two or more primary hydroxyl groups per molecule. The polyols
useful in the practice can be either low or high molecular weight
materials and in general will have average hydroxyl values as
determined by ASTM designation E-222-67, Method B, between about
1000 and 2, and preferably between about 500 and 2. The polyols
include low molecular weight diols, triols and higher alcohols and
polymeric polyols such as polyester polyols, polyether polyols,
polyurethane polyols and hydroxy-containing (meth)acrylic
polymers.
[0108] The low molecular weight diols, triols and higher alcohols
useful in the instant invention are known in the art. For the most
part they are monomeric and have hydroxy values of 200 and above,
usually within the range of 1500 to 200. Such materials include
aliphatic polyols, particularly alkylene polyols containing from 2
to 18 carbon atoms. Examples include ethylene glycol,
1,4-butanediol, 1,6-hexanediol; cycloaliphatic polyols such as
cyclohexane dimethanol. Examples of triols and higher alcohols
include trimethylol propane and pentaerythritol. Also useful are
polyols containing either linkages such as diethylene glycol and
triethylene glycol.
[0109] The most suitable polymeric polyols are those having
hydroxyl values less than 200, such as 10 to 180. Examples of
polymeric polyols include polyalkylene ether polyols, polyester
polyols including hydroxyl-containing polycaprolactones,
hydroxy-containing (meth)acrylic polymers, polycarbonate polyols
and polyurethane polyols.
[0110] Examples of polyether polyols are poly(oxytetramethylene)
glycols, poly(oxyethylene) glycols, poly(oxypropylene) glycols, and
the reaction product of ethylene glycol with a mixture of propylene
oxide and ethylene oxide.
[0111] Also useful are polyether polyols formed from the
oxyalkylation of various polyols, for example, glycols such as
ethylene glycol, 1,4-butane glycol, 1,6-hexanediol, and the like,
or higher polyols, such as trimethylol propane, pentaerythritol and
the like. One commonly utilized oxyalkylation method is by reacting
a polyol with an alkylene oxide, for example, ethylene oxide in the
presence of an acidic or basic catalyst.
[0112] Polyester polyols can also be used as a polymeric polyol
component in the practice of the invention. The polyester polyols
can be prepared by the polyesterification of organic polycarboxylic
acids or anhydrides thereof with organic polyols. Usually, the
polycarboxylic acids and polyols are aliphatic or aromatic dibasic
acids and diols.
[0113] The diols which are usually employed in making the polyester
include alkylene glycols, such as ethylene glycol and butylene
glycol, neopentyl glycol and other glycols such as cyclohexane
dimethanol, caprolactone diol (for example, the reaction product of
caprolactone and ethylene glycol), polyether glycols, for example,
poly(oxytetramethylene) glycol and the like. However, other diols
of various types and, as indicated, polyols of higher functionality
can also be utilized. Such higher polyols preferably include, for
example, trimethylol propane, trimethylol ethane, pentaerythritol,
and the like, as well as higher molecular weight polyols such as
those produced by oxyalkylating low molecular weight polyols. A
particularly preferred example of such high molecular weight polyol
is the reaction product of 20 moles of ethylene oxide per mole of
trimethylol propane.
[0114] The acid component of the polyester polyols consists
primarily of monomeric carboxylic acids or anhydrides having 2 to
18 carbon atoms per molecule. Among the acids which are useful are
phthalic acid, isophthalic acid, terephthalic acid,
tetrahydrophthalic acid, hexahydrophthalic acid, adipic acid,
azelaic acid, sebacic acid, maleic acid, glutaric acid, chlorendic
acid, tetrachlorophthalic acid and other dicarboxylic acids of
varying types. Also, there may be employed higher polycarboxylic
acids such as trimellitic acid and tricarballylic acid (where acids
are referred to above, it is understood that the anhydrides of
those acids which form anhydrides can be used in place of the
acid). Also, lower alkyl esters of acids such as dimethyl glutarate
can be used.
[0115] Besides polyester polyols formed from polybasic acids and
polyols, polycaprolactone-type polyesters can also be employed.
These products are formed from the reaction of a cyclic lactone
such as epsilon-caprolactone with a polyol with primary hydroxyls
such as those mentioned above. Such products are described in U.S.
Pat. No. 3,169,945 to Hostettler.
[0116] In addition to the polyether polyols and polyester polyols,
hydroxy-containing (meth)acrylic polymers or (meth)acrylic polyols
can be used as the polyol component.
[0117] Among the (meth)acrylic polymers are polymers of about 2 to
20 percent by weight primary hydroxy-containing vinyl monomers such
as hydroxyalkyl acrylate and methacrylate having 2 to 6 carbon
atoms in the alkyl group and 80 to 98 percent by weight of other
ethylenically unsaturated copolymerizable materials such as alkyl
(meth)acrylates; the percentages by weight being based on the total
weight of the monomeric charge.
[0118] Examples of suitable hydroxy alkyl (meth)acrylates are
hydroxyl ethyl and hydroxy butyl (meth)acrylate. Examples of
suitable alkyl acrylates and (meth)acrylates are lauryl
methacrylate, 2-ethylhexyl methacrylate and n-butyl acrylate.
[0119] Besides the acrylates and methacrylates, other
copolymerizable monomers which can be copolymerized with the
hydroxyalkyl (meth)acrylates are ethylenically unsaturated
materials such as monoolefinic and diolefinic hydrocarbons,
halogenated monoolefinic and diolefinic hydrocarbons, unsaturated
esters of organic and inorganic acids, amides and esters of
unsaturated acids, nitriles and unsaturated acids and the like.
Examples of such monomers include styrene, 1,3-butadiene,
acrylamide, acrylonitrile, alpha-methyl styrene, alpha-methyl
chlorostyrene, vinyl butyrate, vinyl acetate, alkyl chloride,
divinyl benzene, diallyl itaconate, triallyl cyanurate and mixtures
thereof. Usually these other ethylenically unsaturated materials
are used in admixture with the above-mentioned acrylates and
methacrylates.
[0120] The mean weight average molecular weight M.sub.w of the
uretdione prepolymer, measured with GPC as described above, but
with N,N-dimethylacetamide instead of tetrahydrofurane as solvent
and calculated as M.sub.w is preferably in the range of 20,000 to
800,000 g/mol, particular preferred in the range of 100,000 to
500,000 g/mol.
[0121] The uretdione prepolymer exhibits an acid number of at most
4 mg KOH/g, preferably at most 3.5 mg KOH/g, particularly
preferably 3.0 mg KOH/g, most preferably at most 2.5 mg KOH/g (each
determined according to DIN EN ISO 2114:2002-06). This
significantly reduces the curing time of the aqueous composition.
The acid number is measured according to DIN EN ISO 2114:2002-06.
The sample for determining the acid number essentially consists (or
consists) of 37 wt. % uretdione prepolymer and water and instead of
a mixture of toluene and ethanol as described in DIN EN ISO
2114:2002-06, a mixture of acetone and ethanol in a weight ratio of
2:1 was used.
[0122] The uretdione prepolymer preferably exhibits a zeta
potential of -20 mV or higher. The zeta potential of the uretdione
prepolymer is preferably determined from a dispersion of uretdione
prepolymer in water as the sample. One drop of a preformed
dispersion of the uretdione prepolymer is highly diluted with 20 ml
of demineralized water and homogenized by stirring, leading to the
sample. Subsequently the zeta potential is determined at 23.degree.
C. in the Malvern Nanosizer ZS90 instrument (Malvern Instruments,
Herrenberg, Germany). The given values of the zeta potential are
always related to said sample of the dispersed uretdione
polymer.
[0123] The uretdione prepolymer comprises on average at least one
uretdione group. It is preferred, that the uretdione prepolymer
comprises on average at least two uretdione groups. Preferred
uretdione prepolymers of this invention are self-curing
prepolymers. It is preferred, that the uretdione prepolymer
comprises on average at least two Zerewitinoff-active groups.
During heat induced curing, the uretdione prepolymer will
(self-)crosslink via reaction of said uretdione groups with said
Zerewitinoff-active groups. The more uretdione groups and
Zerewitinoff-active groups are on average comprised in said
uretdione prepolymer (or said reactant), the better.
[0124] It was found, that it was even possible to cure at low
temperature uretdione prepolymers, which were prepared from at
least one aliphatic uretdione polyisocyanate (especially
cycloaliphatic uretdione polyisocyanate), preferably from at least
20 mol % aliphatic uretdione polyisocyanate based on the total
amount of polyisocyanates used, particularly preferred only from
aliphatic uretdione polyisocyanates.
[0125] The uretdione polyisocyanate A1 is used in an amount of 3 to
50 wt.-% based on the total amount of reactants used for
preparation of said uretdione prepolymer.
[0126] The sum of compounds A2 and A3 is preferably used in an
amount of 50 to 97 wt.-% based on the total amount of reactants
used for preparation of said uretdione prepolymer.
[0127] For preparation of said uretdione prepolymer it is
particularly preferred to use the uretdione polyisocyanate A1 in
relation to said compound A2 in a weight ratio from 1:1 to
1:32.3.
[0128] Most preferably, compound A2 is used in a total amount of 1
to 25 wt.-%, preferably 5 to 20 wt.-% and compound A3 is used in a
total amount of 20 to 70 wt.-%, preferably 35 to 65 wt.-%, based on
the total amount of reactants used for preparation of said
uretdione prepolymer.
[0129] The aqueous, curable composition preferably comprises less
organic solvents compared to conventional curing compositions.
According to the invention, water is used in the composition as a
component (preferably as the main component) of the liquid
continuous phase of the dispersion. Replacement of organic
solvents, especially of low-VOC compounds, by water leads to more
ecologically friendly compositions. Preferred compositions
according to the invention are characterized in that they comprise
water preferably in an amount of 10 to 85 wt. %, particularly
preferred in an amount of 30 to 75 wt. %, most preferred in an
amount of 50 to 70 wt. %, also preferred in an amount from 40 to 70
wt. %, most preferred in an amount of 60 to 70 wt. %, based on the
total weight of the composition respectively.
[0130] The aqueous, curable compositions of the invention have a
preferred pH-value at 20.degree. C. of from pH 5 to pH 13, more
preferred from pH 6 to pH 12, even more preferred from pH 7 to pH
9.
[0131] In order to further improve the physiological compatibility,
the composition of the invention is preferably substantially free
of compounds comprising at least one isocyanate group. Due to the
water present in the composition, the majority up to all isocyanate
groups will hydrolyze. Preferably the content of the isocyanate
groups (expressed as NCO, M.G. 42 g/mol) is below 0.05 wt.-%.
Particularly preferred, the composition of the invention is free of
compounds comprising at least one isocyanate moiety. Unless
expressly mentioned otherwise, NCO contents were determined
volumetrically in accordance with DIN-EN ISO 11909 (the DIN-version
used at the application date (or at the priority date if
applicable) of the present invention at the latest version).
[0132] In a preferred embodiment, the composition comprises said
uretdione prepolymer in a total amount of 1 to 50 wt. %, preferably
3 to 40 wt. % and most preferred 30 to 40 wt. %, based on the
weight of the total composition.
[0133] Preferred compositions of this embodiment of the invention
comprise at least one Zerewitinoff-active compound. Suitable
compounds are the compounds as disclosed above for A2 and A3.
Preferred compound are selected from polyester polyol, polyether
polyol, polycarbonate polyol, polyurethane polyol, polyacrylate
polyol, polymethacrylate polyol, C.sub.2-C.sub.10-hydrocarbon with
at least two hydroxyl groups, or mixtures thereof.
[0134] The aqueous, curable composition of this invention
preferably comprises at least one azolate-compound. According to
the Hantzsch-Widman-nomenclature (IUPAC-rule RB-1.2, R-2.3.3.1) an
azole is the generic term for unsaturated five-membered
heterocyclic compounds, comprising in the cycle one nitrogen atom
and in addition to that optionally at least one or more further
hetero atoms including nitrogen atom. An azolate-compound according
to this invention comprises an azole-anion (azolate).
[0135] Preferred azolate compound comprise a five-membered
N-heterocycle. The ring of said preferred N-heterocycle contains an
amount of n nitrogen atoms with n=1, 2 or 3 and an amount of (5-n)
carbon atoms. In addition to that, the five membered ring of said
N-heterocycle comprises two endocyclic double bonds. Said
endocyclic double bonds are preferably conjugated double bonds. The
five-membered N-heterocycle is negatively charged. Said negative
charge is delocalized. Preferably, the endocyclic double bonds
contribute to the delocalization of the negative charge.
[0136] Preferred compositions comprise at least one
azolate-compound of formula (II)
##STR00003##
[0137] wherein
[0138] one, two or three moieties of X.sup.1, X.sup.2, X.sup.3 and
X.sup.4 independently of one another represent the moiety
"--N.dbd." wherein the rest of the moieties of X.sup.1, X.sup.2,
X.sup.3 and X.sup.4 independently of one another represent
"--CR.dbd.", wherein R independently represents H, C.sub.1 to
C.sub.20 alkyl, C.sub.3 to C.sub.20 cycloalkyl C.sub.6 to C.sub.20
aryl, C.sub.1 to C.sub.2 alkoxy, --NR'.sub.2 (R'.dbd.C.sub.1 to
C.sub.20 alkyl), --NO.sub.2, fluorine, chlorine, bromine,
fluorinated C.sub.1-C.sub.6-alkyl, fluorinated
C.sub.1-C.sub.6-alkoxy, cyano, carboalkoxy, --S--R''
(R''.dbd.C.sub.1 to C.sub.20 alkyl), and/or --S--(C.sub.6 to
C.sub.20 aryl) and in the event two adjacent subsitutents of
X.sup.1 to X.sup.4 represent "--CR.dbd.", the substituents R of
these substituents together with the C-atoms of these substituents
may form a further annellated carbo- or heterocyclic, n-membered
ring system where n=3 to 10, wherein the annellated carbo- or
heterocyclic ring system may, independently of one another, contain
one or more heteroatoms (N, 0, S) and may be substituted
independently of one another by one or more the same or different
substituents from the following group: H, C.sub.1 to C.sub.20
alkyl, C.sub.3 to C.sub.20 cycloalkyl C.sub.6 to C.sub.20 aryl,
C.sub.1 to C.sub.2 alkoxy, --NR'.sub.2 (R'.dbd.C.sub.1 to C.sub.20
alkyl), --NO.sub.2, fluorine, chlorine, bromine, fluorinated
C.sub.1-C.sub.6-alkyl, fluorinated C.sub.1-C.sub.6-alkoxy, cyano,
carboalkoxy, --S--R'' (R''.dbd.C.sub.1 to C.sub.20 alkyl), and/or
--S--(C.sub.6 to C.sub.20 aryl), Cat.sup.+ is a counterion.
[0139] The cycle of formula (II) represents a 7c-system, comprising
the two endocyclic double bonds and the delocalized charge.
[0140] The azolate compounds are usually prepared by deprotonation
of a neutral azole compound. Deprotonation is achieved preferably
with a base, preferably with alkaline alkoxides like sodium
methanolate, alkaline earth alkoxides, alkaline hydroxides or
alkaline earth hydroxides. The azolate compound of formula (II) is
prepared by deprotonization of neutral compounds of formula (II-1)
with a base, preferably with at least one of the above mentioned
preferred bases,
##STR00004##
wherein X.sup.1, X.sup.2, X.sup.3 and X.sup.4 are defined according
to formula (II).
[0141] Other suitable neutral compounds for preparation of the
azolate compound according to the invention include pyrrole,
substituted pyrroles and carbocyclic and/or heterocyclic annellated
derivatives of pyrrole.
[0142] Other suitable neutral compounds for preparation of the
azolate compound according to the invention include pyrazole and/or
imidazole, substituted pyrazoles and/or imidazoles and
carbocyclically and/or heterocyclically annellated derivatives of
pyrazole and/or imidazole.
[0143] Other suitable neutral compounds for preparation of the
azolate compound according to the invention include triazole,
preferably selected from 1,2,3- and 1,2,4-triazoles, substituted
species of 1,2,3- and 1,2,4-triazoles and carbocyclically and/or
heterocyclically annellated species of 1,2,3- and
1,2,4-triazoles.
[0144] To produce the azolate compound, in principle all
five-membered N-heterocycles may be used which carry at least one
hydrogen atom bound to a ring nitrogen atom. Examples of these
include pyrrole, indole, carbazole and substituted derivatives such
as 5-nitroindole or 5-methoxyindole, pyrazole, indazole and
substituted derivatives such as 5-nitroindazole, imidazole and
substituted derivatives such as 4-nitroimidazole or
4-methoxyimidazole, benzimidazole or substituted benzimidazoles,
for example 5-nitrobenzimidazole, 5-methoxybenzimidazole,
2-trifluoromethylbenzimidazole, hetero-aromatic annellated
imidazoles such as pyridinoimidazole or purine, 1,2,3-triazole and
substituted derivatives such as
4-chloro-5-carbomethoxy-1,2,3-triazole or
4-chloro-5-cyano-1,2,3-triazole, 1,2,4-triazole and substituted
derivatives such as 3,5-dibromotriazole, 1,2,3-benzotriazole and
substituted 1,2,3-benzotriazole such as
5-fluor-1,2,3-benzotriazole, 5-trifluoromethyl-1,2,3-benzotriazole,
5-nitro-1,2,3-benzotriazole, 5-methoxy-1,2,3,-benzotriazole,
5-chloro-1,2,3-benzotriazole,
5-tetrafluoroethoxy-1,2,3-benzotriazole,
5-trifluorothio-1,2,3-benzotriazole,
4,6-bis-(trifluoromethyl)-1,2,3-benzotriaole,
4-trifluoromethoxy-5-chloro-1,2,3-benzotriazole and heteroaromatic
annellated 1,2,3-triazoles such as the isomeric pyridinotriazoles,
for example the 1H-1,2,3-triazolo[4,5-b]pyridine--referred to in
the remainder of the text as pyridinotriazole- and azapurine.
[0145] In particularly preferred compositions of the invention, the
composition comprises at least one triazolate-compound as component
C).
[0146] Said triazolate-compound is most preferably selected from at
least one triazolate-compound of formula (III) or their
corresponding salts and formula (IV) or their corresponding
salts
##STR00005##
wherein
[0147] R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independent from one
another denote a hydrogen atom, a halogen atom, a nitro group, a
saturated or unsaturated, aliphatic or cycloaliphatic radical, an
optionally substituted aromatic group comprising up to 20 carbon
atoms and optionally up to 3 heteroatoms selected from oxygen,
sulphur, nitrogen, an optionally substituted araliphatic group
comprising up to 20 carbon atoms and optionally up to 3 heteroatoms
selected from oxygen, sulphur, nitrogen, and where R.sup.3 and
R.sup.4 of formula (IV) together with the carbon atoms of the
1,2,3-triazolate five-membered ring form fused rings with 3 to 6
carbon atoms.
[0148] Said triazolate-compound is particularly preferred selected
from alkaline metal-1,2,4-triazolate, alkaline
metal-1,2,3-triazolate, alkaline metal-benzotriazolate, alkaline
earth metal-1,2,4-triazolate, alkaline earth
metal-1,2,3-triazolate, alkaline earth metal-benzotriazolate.
Especially preferred, the triazolate-compound is selected from
alkaline metal-1,2,4-triazolate, alkaline metal-1,2,3-triazolate,
alkaline metal-benzotriazolate. Sodium 1,2,4-triazolate, potassium
1,2,4-triazolate, sodium 1,2,3-triazolate, potassium
1,2,3-triazolate, sodium benzotriazolate, potassium benzotriazolate
and mixtures thereof are the most preferred
triazolate-compounds.
[0149] It was proven advantageous to preferably apply curable
compositions, which comprise said azolate-compound, preferably said
triazolate-compound, in an amount of 0.1 to 10.0 wt. %,
particularly preferred of 0.3 to 3 wt. %, based on the weight of
the composition respectively. Particularly preferred curable
compositions of the invention comprise said uretdione prepolymer in
an amount of 1 to 50 wt. %, preferably 3 to 40 wt. % and most
preferred 30 to 40 wt. % and said azolate-compound, preferably said
triazolate-compound, in an amount of 0.1 to 10.0 wt. %, preferably
0.3 to 3 wt.-%, based on the weight of the composition
respectively.
[0150] In addition to the ingredients mentioned the composition
above may contain various optional ingredients. Examples of these
are dyes, pigments, fillers and reinforcing agents, for example
calcium carbonate, silicates, talc, kaolin, mica and barium
sulfate. Other additives, for example plasticizers, lubricants and
rheological additives and solvent or diluent may be included in the
compositions. When present, these optional ingredients may
constitute up to 50% by weight of the composition based on total
weight of the composition.
[0151] Of particular interest is the use of the compositions of the
invention for preparing coatings on substrates of all kinds. Such
coatings are preferably protective and decorative coatings such as
exterior coatings on substrates of all kinds, for example
buildings, fences, chipboard panels, and as a coating on stone,
concrete or metal, for the coating of vehicles, for example, such
as cars, railways or aircraft. The compositions may likewise be
used in automotive OEM finishing and automotive refinish, and also
for the finishing of car bodies, plastic parts for cars and
body-mounted car parts.
[0152] The compositions of the invention can also be used as
sealants or adhesives.
[0153] Furthermore, the present invention pertains to a process for
curing a liquid composition on a substrate, comprising
[0154] a) applying on a substrate an aqueous, curable composition
according to the present invention; and
[0155] b) exposing the deposited aqueous, curable composition to a
temperature of 60.degree. C. to 160.degree. C. to cure said
deposited curing composition.
[0156] Using known coating processes, the aqueous, curable
composition may be applied uniformly to a substrate, for example by
spin coating, dip coating, knife coating, curtain coating,
brushing, spraying--especially electrostatic spraying--and reverse
roll coating. Said coating compositions can be used as a primer,
color coat or as a clear coat.
[0157] The previously described preferred embodiments of said
aqueous, curable composition are of course also preferably used in
the process of this invention.
[0158] The choice of diluent and the concentration depend
predominantly on the choice of coating ingredients and the coating
process. The diluent should preferably be inert. In other words, it
should not undergo any chemical reaction with the components and
should be capable of being removed after the coating operation in
the curing process. Surprisingly it was found, that especially
water is an appropriate diluent. Examples of suitable diluents are
water, ketones, ethers and esters, such as methyl ethyl ketone,
isobutyl methyl ketone, cyclopentanone, cyclohexanone,
N-methylpyrrolidone, dioxane, tetrahydrofuran, 2-methoxyethanol,
2-ethoxyethanol, 1-methoxy-2-propanol, 1,2-dimethoxyethane, ethyl
acetate, n-butyl acetate and ethyl 3-ethoxypropionate. It is
particularly preferred to use water as diluent.
[0159] It is particularly preferred, that the deposited aqueous
curable composition coalesces to form a coating. The coating
thickness upon drying is typically from 0.5 to 46 .mu.m. If the
coating is a base coat, the coating thickness upon drying is
preferably 15 to 20 .mu.m. If the coating is a top coat, the
coating thickness upon drying is preferably 45 to 50 .mu.m.
[0160] The deposited aqueous, curable composition is preferably
exposed to a temperature of 60 to 120.degree. C., preferably 80 to
100.degree. C., to cure said deposited curing composition.
[0161] According to the process of the invention, the deposited
aqueous, curable composition is preferably exposed to said
temperature for a period of 20 to 45 minutes to cure said deposited
curing composition. It is particularly preferred to expose the
deposited aqueous, curable composition to a temperature of 60 to
120.degree. C., preferably 80 to 100.degree. C., for a period of 20
to 45 minutes.
[0162] It is also preferred to cure said deposited, aqueous curable
composition by preheating the deposited, curable composition to a
temperature of 30.degree. C. to below 60.degree. C. for a period of
2 to 10 minutes. Said preheating is particularly preferred followed
by increasing the temperature to 60 to 160.degree. C. (preferably
to 60 to 120.degree. C., most preferred to 80 to 100.degree. C.)
and exposing for another period of 20 to 45 minutes at said
increased temperature. The preheating step is advantageous, since
the amount of water is reduced in the deposited, curable
composition prior to curing. The subsequent curing reaction at
60.degree. C. to 160.degree. C. is thereby enhanced.
[0163] Preferably, the cured aqueous curable composition forms a
crosslinked film on the substrate, preferably forms a transparent
solid on the substrate, that shows excellent mechanical and optical
properties and a high resistance against chemicals and
solvents.
EXAMPLES
[0164] Compounds:
[0165] Ymer N120 (CAS number: 131483-27-7), a linear,
trimethylolpropane started polyethylene glycol monomethyl ether, OH
number 100-120 mg KOH/g) was acquired from Perstorp Holding AB,
Malmo, Sweden.
[0166] Polyester 1 OH-functional polyester prepared from 3039 g
adipic acid, 4041 g isopthalic acid, 267 g 1,2-propylene glycol,
4773 g neopentyl glycol and 1419 g trimethylol propane (OH number:
181 mg KOH/g, acid number<3 mg KOH/g)
[0167] Other chemicals were--unless otherwise stated--purchased at
Sigma-Aldrich Chemie GmbH, Munich, Germany [0168] IPDI uretdione
("IPDI-dimer"): To 1000 g (4.50 mol) of isophorone diisocyanate
(IPDI) were added at room temperature under dry nitrogen and
stirring 10 g (1%) of triisodecyl phosphite and 20 g (2%) of
4-dimethylaminopyridine (DMAP) as catalyst. After 20 h, the
reaction mixture, which had an NCO content of 28.7%, corresponding
to a degree of oligomerization of 21.8%, was freed from volatile
components without prior addition of a catalyst poison with the aid
of a thin-film evaporator at a temperature of 160.degree. C. and a
pressure of 0.3 mbar. [0169] This gave a pale yellow uretdione with
a content of free NCO groups of 17.0%, a content of monomeric IPDI
of 0.4% and a viscosity (according to DIN EN ISO 3219: 1994-10) of
more than 200,000 mPas (23.degree. C.).
[0170] Measurement Methods:
[0171] Unless noted otherwise, all of the analytical measurements
refer to measurements at temperatures of 23.degree. C.
[0172] All percentages refer, unless otherwise stated, to the
weight.
[0173] The solids contents (non-volatile contents) were determined
by heating a weighed sample (approx. 1 g) at 105.degree. C. to
constant weight. At constant weight, the solid-body content is
calculated by reweighing the sample.
[0174] The pendulum hardness by the Konig method was measured on a
glass plate according to DIN EN ISO 1522:2007-04.
[0175] NCO contents were determined volumetrically in accordance
with DIN-EN ISO 11909:2007-05. The control on free NCO groups was
carried out by means of IR spectroscopy (band at 2260
cm.sup.-1).
[0176] The stated viscosities were determined by means of rotary
viscometry in accordance with DIN 53019:2008-09 at 23.degree. C.
using a rotary viscometer with a shear rate of 186 l/s, from Anton
Paar Germany GmbH, Ostfildern, Germany.
[0177] The average particle sizes (the number-average is given) of
the polyurethane dispersions were determined following dilution
with deionized water by means of laser correlation spectroscopy
(instrument: Malvern Zetasizer 1000, Malver Inst. Limited, London,
UK).
[0178] Zeta potential was measured by diluting one drop of the
sample with 20 ml demineralized water and homogenized by stirring.
Subsequently the zeta potential is determined at 23.degree. C. in
the Malvern Nanosizer ZS90'' (Malvern Instruments, Herrenberg,
Germany).
[0179] Acid number of the respective dispersion was determined
according to DIN ISO 2114 1:2006-11. Instead of a mixture of
toluene and ethanol--as described in DIN ISO 2114 1:2006-11--a
mixture of acetone and ethanol (2:1 by weight) was used as solvent.
The unit of the acid number is mg KOH per g of the analyzed
sample.
[0180] Solvent Resistance and Water Resistance:
[0181] The cured coating films were tested for their resistance to
xylene and water. A piece of cotton wool soaked with the test
substance was placed on the coating surface and covered with a
watch glass. After the specified exposure time, the cotton wool was
removed; the exposed site was dried and immediately inspected. The
evaluation of the softening or discoloring of the coating surface
was carried out following the DIN EN ISO 4628-1:2016-07:
[0182] 0: unchanged, i.e. no perceptible change
[0183] 1: very slight, i.e. barely perceptible change
[0184] 2: slight, i.e. clearly perceptible change
[0185] 3: moderate, i.e. very clearly perceptible change
[0186] 4: considerable, i.e. pronounced change
[0187] 5: very marked change
[0188] Infrared Measurements:
[0189] The uretdione ring opening was characterized by an FT-IR
spectrometer (tensor II with Platinum ATR unit (diamond crystal)
from Bruker). The spectra were recorded in a wave number range of
(4000-400) cm.sup.-1. The maximum of the uretdione peak (about 1760
cm .sup.-1) was evaluated. Peak heights to comparative systems were
compared with an initial value set to 100% (uretdione film without
catalyst, dried at room temperature) and variations relative to
this (ratio formation). Uretdione peak height of films cured for 30
min at 180.degree. C. were set to 0%. When measuring on an ATR
crystal, the intensity of the spectrum depends on the occupation of
the crystal surface. Since a comparable coverage of the crystal
surface cannot be ensured in the case of different measurements by
the sample preparation, a correction of this effect must be made
for the ratio formation by normalizing all spectra on the peak of
the CH stretching vibration (wave number range (3000-2800
cm.sup.-1). In the case of the evaluation of peak heights as
described above, a baseline correction of the spectra is
additionally carried out.
[0190] Preparation of Uretdione Prepolymer Dispersion A (According
to the Invention)
[0191] 149.0 g of "IPDI uretdione" were dissolved in 580 g acetone
at 50.degree. C. in a standard stirring apparatus. 64.6 g of Ymer
N120 and 0.53 g of tin neodecanoate were added and the mixture was
stirred at reflux under atmospheric pressure until the NCO content
of 2.5% was reached. Then 213.2 g of polyester 1 were added and the
mixture was stirred under reflux at atmospheric pressure until the
NCO content dropped below 0.5%. The mixture was then dispersed by
adding 213.2 g of water. The solvent was removed by distillation in
vacuum; solid content was adjusted by addition of water.
[0192] The resulting white dispersion had the following
properties:
[0193] Solids content: 37%
[0194] Average particle size (LCS): 107 nm
[0195] Viscosity (viscometer, 23.degree. C.): 118 mPas
[0196] pH (23.degree. C.): 5.3
[0197] Acid number: 0.9 mg KOH/g
[0198] Zeta potential: -16.4 mV
[0199] Comparative Dispersion 1
[0200] 149.1 g of "IPDI-dimer" were dissolved in 580 g acetone at
50.degree. C. in a standard stirring apparatus. 63.4 g of
Poly(ethylene glycol) methyl ether with an average Mn of 500 g/mol,
214.24 g of a OH-functional polyester 1 and 0.53 g of tin
neodecanoate were added and the mixture was stirred at reflux under
atmospheric pressure until the NCO content dropped below 0.5%. Then
794 g of water were added. The acetone was removed by distillation
in vacuum; solid content was adjusted by addition of water.
[0201] The resulting white dispersion had the following
properties:
[0202] Solids content: 35.7%
[0203] Average particle size (LCS): 166 nm
[0204] Viscosity (viscometer, 23.degree. C.): 20 mPas
[0205] pH (23.degree. C.): 5.4
[0206] Preparation of Anionic Uretdione Prepolymer Dispersion
(Comparative Example) Comparative Dispersion 2
[0207] 150.3 g of "IPDI-dimer" were dissolved in 594 g acetone at
50.degree. C. in a standard stirring apparatus. 12.8 g of
dimethylol propionic acid, 201.3 g of a OH-functional polyester 1
and 0.55 g of tin neodecanoate were added and the mixture was
stirred at reflux under atmospheric pressure until the NCO content
dropped below 0.5%. Then 8.5 g N,N-dimethylamino-ethanol and 670 g
of water were added. The acetone was removed by distillation in
vacuum; solid content was adjusted by addition of water.
[0208] The resulting white dispersion had the following
properties:
[0209] Solids content: 35.6%
[0210] Average particle size (LCS):108 nm
[0211] Viscosity (viscometer, 23.degree. C.): 5 mPas
[0212] pH (23.degree. C.): 8.5
[0213] Acid number: 7.3 mg KOH/g
[0214] Zeta potential: -45.7 mV
[0215] Tests of the Coatings
[0216] Clear coatings were prepared from the following
composition:
[0217] 100 weight percent (20 g) of urethane prepolymer dispersion
A (or comparative) was mixed with 6 weight percent (1.2 g) of a
solution consisting of 0.12 g 1,2,4-Triazolate-Na and 1.08 g
water.
[0218] The mixture was applied to glass or coil (CS-300570 coil
coating test panel, purchased from Zanders PBL) using a coating
squeegee with a layer thickness of 150-180 .mu.m (wet). The plates
were dried at room temperature for 5 minutes and then baked at
various temperatures for 30 minutes. The obtained films were
evaluated at 23.degree. C. at 50% relative humidity by pendulum
hardness, water resistance and solvent resistance and an IR
spectrum was recorded.
[0219] The following table shows the coating properties of the
corresponding films.
[0220] Requirements for Coatings:
[0221] Pendulum hardness>100 s
[0222] Xylene test:<4
[0223] 10 weeks stable at room temperature and 40.degree. C.
Inventive Examples Ex1 (with Catalyst) and Ex 2 (without
Catalyst)
[0224] Clear Coat of the Following Compositions:
TABLE-US-00001 Ex 1 Ex 2 Dispersion A 20 g 20 g Catalyst
1,2,4-Triazolate-Na 1.2 g (10% in water)
[0225] Coating Properties (Before Storage):
TABLE-US-00002 Ex 1 Ex 2 Curing Time, 1 day; 1 day; Temperature
room temp. room temp. Remaining intensity of IR- Percent >97%
>97% peak with peak maximum between 1750 and 1800 cm.sup.-1
Resistance against xylene 5 min 5 5 Ex 1 Ex 2 Curing Time, 30 min;
30 min; Temperature 100.degree. C. 100.degree. C. Remaining
intensity of IR- Percent <3% >97% peak with peak maximum
between 1750 and 1800 cm.sup.-1 Resistance against xylene 5 min 2 5
Ex 1 Ex 2 Curing Time, 30 min; 30 min; Temperature 140.degree. C.
140.degree. C. Remaining intensity of IR- Percent <3% 92% peak
with peak maximum between 1750 and 1800 cm.sup.-1 Resistance
against xylene 5 min 2 5
[0226] Coating Properties of Inventive Dispersion (Ex 1) which were
Stored Beforehand at Room Temperature and at 40.degree. C.:
TABLE-US-00003 20 g stored at 20 g stored at room temperature
40.degree. C. Ex 1 for 10 weeks for 10 weeks Curing Time, 30 min;
30 min; Temperature 100.degree. C. 100.degree. C. Remaining
intensity of IR- Percent <3 <3 peak with peak maximum between
1750 and 1800 cm.sup.-1 Resistance against xylene 5 min 2-3 2-3
Comparative Examples 1 and 2: Comparative Dispersion 1
[0227] Clearcoat of the Following Compositions:
TABLE-US-00004 Comp. Ex 1 Comp. Ex 2 Comp. Dispersion 1 20 g 20 g
Catalyst 1,2,4-Triazolate-Na 1.2 g (10% in water)
[0228] Coating Properties (Before Storage):
TABLE-US-00005 Comp. Ex 1 Comp. Ex 2 Curing Time, 30 min; 30 min;
Temperature 100.degree. C. 100.degree. C. Remaining intensity of
IR- Percent <3% >97% peak with peak maximum between 1750 and
1800 cm.sup.-1 Resistance against xylene 5 min 4 5 Comp. Ex 1 Comp.
Ex 2 Curing Time, 30 min; 30 min; Temperature 140.degree. C.
140.degree. C. Remaining intensity of IR- Percent <3% >97%
peak with peak maximum between 1750 and 1800 cm.sup.-1 Resistance
against xylene 5 min 4 5
Comparative Examples 3 and 4: Comparative Dispersion 2
[0229] Clearcoat of the Following Compositions:
TABLE-US-00006 Comp. Ex 3 Comp. Ex 4 Comparative Dispersion 2 20 g
20 g Catalyst 1,2,4-Triazolate-Na 1.1 g (10 wt.-% in water)
[0230] Coating Properties (Before Storage):
TABLE-US-00007 Comp. Ex 3 Comp. Ex 4 Curing Time, 30 min; 30 min;
Temperature 100.degree. C. 100.degree. C. Remaining intensity of
IR- Percent >97 >97 peak with peak maximum between 1750 and
1800 cm.sup.-1 Resistance against xylene 5 min 5 5 Comp. Ex 3 Comp.
Ex 4 Curing Time, 30 min; 30 min; Temperature 140.degree. C.
140.degree. C. Remaining intensity of IR- Percent >97 >97
peak with peak maximum between 1750 and 1800 cm.sup.-1 Resistance
against xylene 5 min 4 4
[0231] Coating properties of non-inventive dispersions after
storage at 40.degree. C. or with catalyst could not be performed
due to instability of these dispersions.
[0232] Stability Measurements of Examples and Comparative Example
1:
[0233] Dispersions were stored at room temperature or in a
40.degree. C. oven with or without catalyst for 10 weeks. Stability
of dispersion was evaluated by IR measurement before/after
storage.
TABLE-US-00008 Inventive Comparative Dispersion Example A
dispersion 1 Remaining intensity of IR-peak >97% Thickened after
after storage at room temperature storage at RT without catalyst
for 10 weeks for 8 weeks (peak maximum between 1750 and 1800
cm.sup.-1) Remaining intensity of IR-peak >86% Thickened after
storage at 40.degree. C. without catalyst for 10 weeks (peak
maximum between 1750 and 1800 cm.sup.-1) Remaining intensity of
IR-peak 87 Thickened after storage at room temperature with
catalyst for 10 weeks (peak maximum between 1750 and 1800
cm.sup.-1) Remaining intensity of IR-peak 44% Thickened after
storage at 40.degree. C. with catalyst for 10 weeks (peak maximum
between 1750 and 1800 cm.sup.-1)
* * * * *