Note: Descriptions are shown in the official language in which they were submitted.
2~a~
Mo3351
LeA 26,872
TWO-COMPONENT COMPOSITIONS AND
COATINGS AND SEALANT~ PRODUCED THEREFROM
BACKGROUND OF THE_IYY~YlI9
Field of the Invention
The present invention relates to novel compositions and
coatings and sealants produced therefrom. These compositions
can be used with little or no solvent and are based on special
prepolymers cnntaining isocyanate groups and compounds
containing isocyanate reactive groups or groups convertible
o into such groups.
Descrietion of the Prior Art
Coating compositions based on isocyanate prepolymers and
compounds containing isocyanate reactive groups or groups
conYertible into such groups are known. Thus DE-OS 1 520 139,
for example, describes a process for the preparation of
moisture hardening mixtures of palyisocyanates and
polyketimines or polyaldimines in which the polyisocyanates
used are preferably isocyanate prepolymers; DE-AS 1 240 654
describes a process for the preparation of cross-linked resins
from ~socyanate prepolymers and special aromatic diamines; and
DE-OS 2 018 233 describes moisture hardening preparations of
compounds containing isocyanate groups and polyoxazolidines.
Common to all of these publications is the use of known
isocyanate prepolymers which are prepared by the reaction of
relatively high molecular weight polyhydroxyl compounds such as
polyether or polyester polyols with excess quantities of di- or
polyisocyanates. The reaction products generally contain
relatively high proportions of monomeric di- or polyisocyanates
which in many cases must be removed for purposes of industrial
hygiene, e.g., by thin layer distillation.
The monomer-free isocyanate prepolymers thus obtained
always have much higher viscosities than the starting compounds
and therefore in many cases require the addition of organic
353761~R0706
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: ~ , .. ,: . ~ . . . ..
: - .: ` - : : :
: . :............. : :, . ~ -
: .'. ~ ' ' ',: ~ , .
201~
solvents or plasticizers before they can be used for the
preparation of lacquers or coating materials.
It is well known, however, that the use of solvents is
undesirable for ecological reasons and often regulations
5 require the coating compositions to have the lowest possible
solvent content. The use of plasticizers also has
disadvantages. Plasticizers remain in the coatings and, thus,
impair the mechanical properties of the polymers and their
adherence to the substrate and over time migrate from the
coatings.
It is therefore an object of the present invention to
provide new two-component compositions based on isocyanate
prepolymers and compounds containing isocyanate reactive groups
or groups convertible into such groups which have substantially
15 lower viscosities than comparable ~nown compositions so that
they can be applied with less solvent or without solvent or
plasticizer.
This obiect may be achieved in accordance with the present
invention by using compositions wherein the polyisocyanate
component is based on certain isocyanate prepolymers containing
ester groups.
Isocyanate prepolymers which are similar to the isocyanate
prepolymers used as the polyisocyanate component according to
the present have been described in DE-OS 2 120 090; however,
25 the isocyanate prepolymers disclosed in this prior publication
are used for finishing textiles containing keratin fibers and
must be used in the form of highly diluted organic solutions or
aqueous emulsions. There is no indication in this prior
publication that the isocyanate prepolymers are particularly
30 suitable for the preparation of low solvent or solvent-free
coating compositions. In particular, there is absolutely no
indication to prepare isocyanate prepolymers, which are
particularly suitable for the present invention, by the process
described hereinafter.
Mo3351
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. .
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2015~4~
-3 -
SUMMARY OF THE INVENTIO~
The present invention relates to two-component coating or
sealing compositions which contain
a~ a polyisocyanate component and
b) a reactive component consisting of at least one compound
containing at least two isocyanate reactive groups which
are ~ptionally reversibly blocked
in quantities corresponding to an equivalent ratio of
isocyanate groups to free and blocked isocyanate reactive
: lo groups of about 0.8:1 to 10:1 characterized in that
polyisocyanate component a~ is based on compounds corresponding
to the formula
A- [O-CO-B-NCO~n
wherein
n is an integer of 2 or greater,
A is an n-valent organic group obtained by removing the
hydroxyl groups from an n-valent organic polyhydroxyl
compound having a molecular weight of 400 to about 20,000,
such compound being inert to isocyanate groups at room
temperature with the exception of its hydroxyl groups and
B is an aliphatic, cycloaliphatic or aromatic hydrocarbon
group optionally having substituents which are inert to
the reactive groups present in the compositions.
The present invention also relates to coatings or sealants
prepared from these two-component compositions.
DETAILED DESCRTPTION OF THE INVENTION
Polyisocyanate component a) consists substantially of
compounds corresponding to the formula
A-[O-CO-B-Nco]n
wherein
Mo335 1
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.. ; ~., . . . . . . . ~ , :., , , .,. :
:, . . . . .: ~ - ~
. .
.. . . .
2013B~O
n, A and B have the meanings already ;ndicated. It is preferred
to use those isocyanate prepolymers corresponding to the above
mentioned fonmula wherein
n stands for an integer having a value of 2 to 8, more
preferably 2 to 4,
A denotes an n-valent group obtained by removing the
hydroxyl groups from a polyhydroxyl compound having a
molecular weight of about sno to 5000 and containing
ether, ester, carbonate and/or urethane groups and
B denotes an aliphatic hydrocarbon group containing 2 to 10
carbon atoms, preferably 4 to 8 carbon atoms, or a
cycloaliphatic hydrocarbon group containing 6 carbon
atoms, provided that at least two carbon atoms are
situated between the carbonyl group and ~he isocyanate
group.
The isocyanate prepolymers corresponding to the above
formula are prepared by modifying organic polyhydroxyl
compounds corresponding to the formula
A(OH)n
This modification may involve reacting the polyhydric
alcohols with isocyanatocarboxylic acid chlorides corresponding
to the formula
Cl-CO-B-NCo
in accordance with the teachings of DE-OS 2 120 090.
Conversion of the above-mentioned polyvalent polyhydroxyl
compounds into the isocyanate prepolymers used as component a)
according to the invention is preferably carried out by a
process analogous to that described in DE-OS 3 634 248.
In this process, the polyhydroxyl compounds are converted
into corresponding O-silylated compounds corresponding to the
formula
Mo3351
:,.:. - ~ .,: ., : - -,
2 ~
-5-
A-[0-SiR3]n
in a first reaction stage which is analogous to the process
described by M. Lalonde and C.H. Chan in "Synthesis" 1985,
pages 817 to 845. The polyhydroxyl compounds are reacted with,
5 for example, chlorosilanes or disilazanes corresponding to the
formulas
R35iCl or R3Si-NH-SiR3,
optionally in the presence of an auxiliary solvent. The
reaction with chlorosilane is generally carried out at a molar
ratio of hydroxyl groups to chlorosilane of 1:1 to 1:2 and at
temperatures of about 0 to ~0C. The reaction generally
requires the addition of at least an equimolar quantity of an
15 organic base such as pyridine or triethylamine for binding the
hydrogen chloride formed in the reaction. The reaction with
disilazanes is preferably carried out at a molar ratio of
hydroxyl groups to disilazane of 1:0.5 to 1:1 at temperatures
of about 60 to 140C until ammonia ceases to be split off. It
20 iS frequently advisable to add a small quantity of an acid
catalyst such as p-toluene sulfonic acid or trimethyl
chlorosilane.
The solvents optionally used for this reaction include
n-hexane, cyclohexane, toluene, xylene, methoxypropylacetate,
25 ethyl acetate, butyl acetate, methyl ethyl ketone or mixtures
of such solvents. Chlorosilanes and disilazanes which are
particularly suitable for the reaction are those correspond;ng
to the above formulae wherein R is an alkyl group with 1 to 4
carbon atoms or a phenyl group, preferably a methyl group.
The 0-silylated polyhydroxyl compounds are then reacted
with isocyanatocarboxylic acid chlorides corresponding to the
above formula. The components for this reaction are used in
quantities which provide about 0.~ to 1.2 moles of silylated
hydroxyl groups for each mole of chlorocarbonyl groups.
Mo3351
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.
~: .
2 0 ~
-6-
Equimolar ratios of reactants are preferably maintained. The
reaction of the silylated hydroxyl compounds with
isocyanatocarboxylic acid chlorides is generally carried out at
temperatures of about 50 to 150C, optionally with the addition
of catalysts commonly used for this reaction, such as quinoline
or pyridine.
A trialkyl or triaryl chlorosilane is formed as by-product
of the reaction according to the invention and can easily be
removed from the reaction mixture by distillation.
This reaction may also be carried out either in the
presence or the absence of a solvent of the type exemplified
above. Solvents may generally be omitted if the silylated
; hydroxyl compounds have a sufficiently low viscosity for
carrying out the process according to the invention.
: 15 Because it is an object of the present invention to
provide binders with as low a solvent content as possible, the
use of solvents is less preferred; however, residues of
volatile components may be removed from the prepolymers by thin
layer distillation.
The polyhydroxyl compound used for the preparation of
polyisocyanate component a) may be any organic polyhydroxyl
compound which has a molecular weight range of 400 to about
20,000, which is at least divalent and which, apart from its
hydroxyl groups, is inert to isocyanate groups at room
temperature such that the isocyanate prepolymers are stable in
storage at room temperature. These polyhydroxyl compounds,
A(OH~, preferably have a molecular weight of about 800 to 5000
and contain ether, ester, carbonate and/or urethane groups. The
molecular weights may be determined, for example, by gel
permeation chromatography (MW > 5000) or from the hydroxyl
group content and OH fùnctionality (MW ~ 5000).
The isocyanate prepolymers a) may be prepared, for
example, from known relatively high molecular weight polyols of
the type used as raw materials in polyurethane chemistry.
Examples of such compounds are given in High Polymers, Vol.XVI,
Mo3351
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'. ` . ~ ' ' . '
"' ~ ' ' ' ' , ;' ' ' . ' ~ . ., '~
2 ~
-7-
"Polyurethanes, Chemistry and Technology", by Saunders-Frisch,
Interscience Publishers, New York, London, Volume I, 1962,
pages 32-42 and pages 44-54 and Volume II, 1964, pages 5-6 and
198-199; and in Kunststoff-Handbuch, Volume VII,
5 Vieweg-Hochtlen, Carl-Hanser-Verlag, Munich, 1966, e.g. on
pages 45-71.
Polyhydroxyl compounds containing two or more different
groups of the type mentioned above and mixtures of different
polyhydroxyl compounds of the type mentioned above are also
o suitable. Suitable polyether polyols for use in accordance
with the invention may be prepared, for example, by the
polymerization of epoxides (such as ethylene oxide, propylene
oxide, butylene oxide, tetrahydrofuran, styrene oxide or
epichlorohydrinJ on their own (e.g. in the presence of Lewis
5 catalysts such as BF3) or by chemical addition of these
epoxid~s, preferably ethylene oxide and propylene oxide,
optionally as mixtures or successively, to starter compounds
containing reactive hydrogen atoms (such as water, alcohols,
ammonia or amines). Examples of suitable starter compounds
20 include ethylene glycol, propylene glycol-(1,3~ or -(1,2),
trimethylolpropane, glycerol, sorbitol,
4,4'-dihydroxy-diphenylpropane, aniline, ethanolamine and
ethylene diamine. Sucrose polyethers such as those described,
for example, in German Auslegeschriften 1 176 358 and 1 063 938
25 and polyethers started on formitol or formose (German
Offenlegungsschriften 2 639 083 and 2 737 951) may also be
used.
The polyester polyols which may be used according to the
invention are also known and are based on reaction products of
30 polyhydric, preferably dihydric alcohols, optionally with the
addition of trihydric alcohols, with polybasic, preferably
dibasic carboxylic acids. Instead of the free polycarboxylic
acids, the corresponding polycarboxylic acid anhydrides or
corresponding polycarboxylic acid esters of lower alcohols or
35 mixtures thereof may be used for preparing the polyesters. The
Mo3351
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c.
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- . . , ~ , -
.
2 ~ ~ 3
polycarboxylic acids may be alipha~ic, cycloal iphatic, aro~atic
and/or heterocyclic and may be unsaturated and/or substituted,
e.g. by halogen atoms.
Examples of suitable carboxylic acids and their
;~ 5 derivatives include succinic acid, adipic acid, suberic acid,
azelaic acid, sebacic acid, phthalic acid~ isophthalic acid,
trimellitic acid, phthalic acid anhydride, tetrahydrophthalic
acid anhydride, hexahydrophthalic acid anhydride,
tetrachlorophthalic acid anhydride, endomethylene
tetrahydrophthalic acid anhydride, glutaric acid anhydride,
maleic acid, maleic acid anhydride, fumaric acid, dimerized and
trimerized unsa~urated fatty acids (optionally mixed with
monomeric unsaturated fatty acids such as oleic acid),
terephthalic acid dimethylester and terephthalic acid
bis-glycol ester. Examples of suitable polyhydric alcohols
include ethylene glycol, propylene glycol-(1,2~ and -(1,3),
butylene glycol-(1,4) and -(2,3), hexanediol-(1,6),
octanediol-~1,8), neopentyl glycol, 1,4-bis-hydroxymethyl-
cyclohexane, 2-methyl-1,3-propanediol, glycerol,
trimethylolpropane, hexanetriol-(1,2,6~ butanetriol-(1,2,4)
trimethylolethane, pentaerythritol, quinitol, mannitol and
sorbitol, formitol, methyl glycoside, diethylene glycol,
triethylene glycol and tetraethylene glycol and higher MW
polyethylene glycols, dipropylene glycol and higher MW
polypropylene glycols and dibutylene glycol and higher MW
polybutylene glycols.
Polyesters of lactones such as ~-caprolactone or
hydroxycarboxylic acids such as ~-hydroxycaproic acid may also
be used.
Suitable hydroxyl polycarbonates are known and include ;-~
those obtained by the reaction of diols such as -~
propanediol-(1,3), butanediol-(1,4) and/or hexanediol-(1,6)
diethylene glycol, triethylene glycol, tetraethylene glycol or ~ -
thiodiglycol with phosgene or diarylcarbonates such as
diphenylcarbonate (German Auslegeschriften Nos. l 694 080, 1
Mo3351
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~ - .
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- - .
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, ;.: . . . . : . . , . :
: . . -; .. .. , -, , .
~ . ~ :-, . :
,.. . . .. . ..
2 ~ 0
915 gO8 and 2 221 751; German Offenlegungsschrift No.
2 6~5 0243.
Polyester polycar~onates containing hydroxyl groups which
may be obtained, for example, according to DE-AS 1 770 245 are
also suitable. These compounds may be prepared, e.g., by
reacting ~-caprolactone with polyols such as hexane-1,6-diol
followed by a reacting the resulting ester glycols with
diphenylcarbonate.
Suitable polyurethane polyols for use in accordance with
n the present invention are prepared by the polyaddition of one
or more of the previously mentioned relatively high molecular
weight polyhydroxyl compounds, optionally in admixture with low
molecular weight polyols such as ethylene glycol, propylene
glycol-(1,2) and -(1,3), butylene glycol-(1,4~ and -(2,3),
hexanediol-(1,6), octanediol-(1,83, neopentyl glycol,
1,4-bis-hydroxymethylcyclohexane, 2-methyl-1,3-propanediol,
glycerol, trimethylolpropane, diethylene glycol, dipropylene
glycol or higher MW polyalkylene glycols w;th polyisocyanates
such as 2,4- and/or 2,6-toluylene diisocyanate, diphenyl-
methane-2,4'- and/or -4,4'-diisocyanate, 1,6-hexamethylene-
diisocyanate, cyclohexane-1,3- andtor -1,4-diisocyanate,
l-isocyanato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane
(isophorone diisocyanate), 4,4'-dicyclohexylmethane
diisocyanate and/or adducts of the above mentioned
polyisocyanates containing biuret or isocyanurate groups. The
polyhydroxyl compounds and pGlyisocyanates are used in
quantitative proportions such that the hydroxyl groups are
present in stoichiometric excess to the isocyanate groups.
Suitable isocyanatocarboxylic acid chlorides corresponding
to the above formula which are suitable for the preparation of
the isocyanate prepolymers a) include 3-isocyanatopropionic
acid chloride, 4-isocyanatobutyric acid chloride,
6-isocyanatocaproic acid chloride, 11-isocyanatoundecanoic acid
chloride and 4-isocyanatocyclohexane carboxylic acid chloride.
Mo3351
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.: . : ,: , .: . :
.
. :: . . .
~ , ~
2 ~
- 10-
In addition to these preferred isocyanatocarboxylic
acid chlorides, it is also possible to use isocyanato
carboxylic acid chlorides which correspond to the above formula
wherein B is an aromatic hydrocarbon group optionally
5 containin~ inert substituents. 4-isocyanatobenzoic acid
chloride is given as an example of these compounds.
The isocyanate prepolymers used as component a) according
to the invention are distinguished by their low monomer content
and exceptionally low viscosities.
Reactive component b~ is based on at least one compound
containing at least two isocyanate reactive groups or at least
two groups capable of being converted, preferably
hydrolytically, into such groups. Compounds containing both
free and reversibly blocked isocyanate reactive groups may also
15 be used but are less preferred. Also, mixtures of compounds
having free isocyanate reactive groups and compounds having
reversibly blocked isocyanate reactive groups may also be used
but are less preferred. The compounds used as component b)
preferably contain 2 to 4 free or blocked isocyanate reactive
20 groups per molecule. The molecular weight of the compounds
used as component b) is not critical but comparatively low
molecular weight compounds, i.e., compounds haviny a molecular
weight of not more than 600, are preferably used.
The quantity of the components used in the coating
compositions according to the present invention is chosen to
provide a ratio of (i) isocyanate groups of component a) to
(ii) free and/or reversibly blocked isocyanate reactive groups
of component b) of about 0.8:1 to 10:1, preferably about 0.9:1
to 4:1, more preferably 1:1 to 2:1 and most preferably 1:1 to
1.2:1.
The following may be used as as all or a portion of
component b):
- Polyoxazolidines which are known from polyurethane
chemistry and described, e.g., in DE-PS 2 018 233 (US-PS 3
Mo3351
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'' , ~ : : .
2 0 ~
743 626, herein incorporated by reference) and DE-OS 2 446
438 (US-PS 4 002 601, herein incorporated by reference);
- polyketimines or polyaldi~ines which are known from
polyurethane chemistry and described, e.g., in DE-OS l 520
139, (US-PS 3 420 800 and US-PS 3 ~67 692, both of which
are herein incorporated by reference) or DE-OS 3 308 418
(US-PS 4 481 345, herein incorporated by reference);
- aromatic polyamines, in particular diamines containing
sterically hindered amino groups, e.g., those used as
chain lengthening agents according to US-PS 4 218 543,
herein incorporated by reference, preferably
l-methyl-3,5-diethyl-2,4-diaminobenzene a~d mixtures
thereof with l-methyl-3,5-diethyl-2,6-diaminobenzene; and
- polyhydric alcohols having a molecular weight of 62 to 39g
as well as polyhydric alcohols having a molecular weight
of at least 400. Examples of low molecular polyhydric
alcohols include ethylene glycol, propylene glycol,
butane-1,4-diol, glycerol, trimethylolpropane,
pentaerythritol, diethylene glycol, dipropylene glycol and
2~ mixtures of such polyols. Examples of suitable higher
molecular weight alcohols include the starting materials
A(OH)n mentioned above as examples for the preparation of
polyisocyanate component a). Other polyhydroxyl compounds
which are suitable include epoxide resins, phenol resins,
alkyl resins, castor oil, polyester resins containing
hydroxyl groups and silicone resins containing hydroxyl
groups.
For the preparation of the two-component compositions
according to the invention, the individual components a) and b)
are mixed together. When component b) contains reversibly
blocked isocyanate reactive groups, in particular reversibly
blocked amino groups, storage stable preparations are obtained
which remain stable in the absence of moisture and rapidly
harden in the presence of moisture after they have been applied
to a suitable substrate. The hardening reaction may also be
Mo3351
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- . : ~ ` . . . . . .
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~V~ 4~
-12-
accelerated by the addition of known catalysts such as
p-toluenesulphonic acid, dibutyl tin octoate or zinc
chloride.
When the reactive components b3 contain free isocyanate
reactive groups, in particular amino or hydroxyl groups, the
reaction mixtures obtained will react at room temperature to
form polyurethanes or polyureas, i.e. they have only a limited
pot life and must be worked up within this period.
The term "two-component compositions" means that the
o compositions according to the invention are composed of the
individual components a) and b) and when blocked reactive
components b) are used then the individual components may also
be combined to form a one-component system.
Inert organic solvents or plasticizers may be added to the
individual components or to the combinations according to the
invention before, during or after the compositions have been
prepared by mixing of the individual components a) and b).
These solvents or plasticizers should be substantially
free from water to ensure sufficient storage stability of the
binders, especially when polyoxazolidines, polyketimines or
polyaldimines are used as component b). The use of solvents or
plasticizers is however, not preferred in view of the object of
the invention to produce binders which have as low a solvent
content as possible.
The addition of pigments and other auxiliary agents and
additives required for most applications such as fillers,
levelling agents, etc. is preferably carried out by adding the
additives to one of the starting components before the
preparation of the compositions according to the invention.
The compositions according to the invention are
particularly suitable for the preparation of coatings and
sealants. The coating compositions according to the invention
may be applied as one or more layers to any substrates by known
methods such as spraying, spread coating, immersion, flooding
35 or application with rollers or knife coaters. Suitable
Mo3351
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,~
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2 ~
-~3-
substrates include metal, wood, glass, stone, ceramic
materials, concrete~ hard and flexible plastic textiles,
leather and paper.
The substrates may, of course, be coated with the known
primers before application of the coating compositions
according to the invention.
The following examples serve to illustrate the invention
in more detail. Percentages are percentages by weight and
parts are parts by weight unless otherwise indicated.
o EXAMPLES
General method of preparation of O-silylated polyhydroxyl
compounds ~_
The O-silylated polyhydroxyl compounds used for the
preparation of isocyanate prepolymers I to III were prepared
from the corresponding polyhydroxyl compounds by reacting them
with hexamethyldisilazane:
1 OH equivalent of the hydroxyl compound and 0.8 moles of
hexamethyldisilazane were stirred together at 100 to 120C with
the addition of 0.5 g of trimethylchlorosilane until evolution
of NH3 ceases. The progress of the reaction was followed by
observation of the OH band by IR spectroscopy. After the
reaction, excess disilazane was removed from the reaction
mixture by distillation.
Isocvanate prepolvmer I
1073 g of an O-silylated polyether ~based on
trimethylolpropane and propylene oxide, OH number = 56,
viscosity at 22C = 500 mPas) and prepared by the above method
and 175.5 9 of 6-isocyanatocaproic acid chloride were stirred
together at 80 to 100C with the addition of 1 ml of pyridine
until the IR spectrum showed no acid chloride band.
Trimethylchlorosilane produced during the reaction was
continuously removed by distillation. An isocyanate prepolymer
having the followin~ characteristics was obtained after thin
layer distillation at 140C/0.05 mbar:
NCO content = 3.45%;
Mo3351
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, , - , . . .
.: . : . , ,
- , , ;.
. , - -
2 0 ~ ~ ~ 4 ~
-14-
viscosity at 22C = 600 mPas.
IsocYanate DrepolYmer II
1073 9 of an O-silylated polyester carbonate diol [based
on a polyester carbonate diol prepared according to DE-AS 1 770
245 (U.S. Patent 3,640,967) from hexane-1,6-diol,
~-caprolactone and diphenylcarbonate in a molar ratio of about
8:8:7, OH number = 56, viscosity at 22nC = 20,000 mPas]
prepared by the above-described method and 175.5 g of
6-isocyanatocaproic acid chloride were reacted as described
above for the preparation of isocyanate prepolymer I. After
removal of residues of volatile constituents by thin layer
distillation, the isocyanate prepolymer obtained had the
following characteristics:
NCO content = 3.2%,
viscosity at 22C = 20,000 mPas.
Isocvanate prepolYmer III
1673 g of an O-silylated polyether triol (based on a
polyether triol prepared by the propoxylation of
trimethylolpropane followed by ethoxylation of the
propoxylation product at a PO:EO ratio by weight of 86.5:13.5,
OH number = 35, viscosity at 22C = 500 mPas) prepared by the
method described above and 175.5 g of 6-isocyanatocaproic acid
chloride were reacted as described above for the preparation of
isocyanate prepolymer I. The isocyanate prepolymer obtained
had the following characteristics after thin layer distillation
at 140C/0.05 mbar:
NCO content = 2.46%,
viscosity at 22C = 600 mPas.
IsocYanate Dre wlvmer IV
A mixture of 1000 9 of the polyester carbonate diol used
for the preparation of isocyanate prepolymer II, 500 ml of
ethyl acetate and 102 g of triethylamine was added dropwise to
a solution of 175.5 g of isocyanatocaproic acid chloride in 300
ml of ethyl acetate at room temperature at such a rate that the
temperature did not rise above 30 C. The reaction mixture was
Mo3351
~ . . , . . . ~ ..
.. . . ..................... :.,: ;, .
., - . - , . . . . .
20~5~
-15-
stirred overnight and filtered from the precipitated ammonium
salt. The filtrate was freed from volatile constituents by
thin layer evaporation. The isocyanate prepolymer obtained had
the following character;stics:
: 5 NC0 content = 3.16%
viscosity at 22C = 80,000 mPas.
Example_l
88 parts of isocyanate prepolymer I were mixed with 12
parts of a bisoxazolidine prepared from 2 moles of
2-(2-isopropyl-1,3-oxazolidin-3-yl)ethanol and 1 mole of
hexamethylene diisocyanate. The mixture was completely stable
in a closed container. The solvent-free mixture thus prepared
had a viscosity of 800 mPas (22C). When the compound was
applied in a thickness 8 mm, it hardened in air at room
temperature to an elastic coating.
Example 7
93 parts of isocyanate prepolymer I were thoroughly mixed
with 7 parts of 1-methyl-3,5-diethyl-phenylenediamine-(2,4).
The mixture obtained had a pot life of 15 minutes. A film of
lacquer applied at room temperature was pressure dry after
about 40 minutes. After aging, the film had a Shore A hardness
of 66.
Example 3
89 parts of isocyanate prepolymer II were intimately mixed
25 with 11 parts of the bisoxazolidine described in Example 1. A
solvent-free mixture which was completely stable in closed
containers and had a viscosity of 17,000 mPas (22C) was
obtained. The mixture hardened in air at room temperature to
form tough elastic films which had excellent abrasion
30 resistance.
Example 4
187 parts of isocyanate prepolymer II were vigorously
mixed with 13 parts of 1-methyl-3,5-diethyl-phenylenediamine-
(2,4). The solvent-free mixture had an initial viscosity of
35 20,000 mPas (22C) and a pot life of 15 minutes. A film
Mo3351
.. .. , . ~ . .
. , ... , , . . . ~ . .
,: , , ~ - . . . .
:............. .. . - . : : :
. : ~ , - .. ` : -
: . - . , . .
. - . ~ .
2 ~
-16-
applied at room temperature was pressure dry after about 40
minutes. A tough elastic film with good abrasion resistance
was obtained after aging.
ExamPle 5
95 parts of isocyanate prepolymer III were intimately
mixed with S parts of 1-methyl-3,5-diethyl-phenylenediamine-
(2,4). The solvent-free mixture had an initial viscosity of
650 mPas (22C) and a pot life of 20 minutes. A lacquer film
applied at room temperature was pressure dry after about 90
minutes. A highly elastic film was obtained after aging.
Example 6
~1 parts of isocyanate prepolymer II were mixed with 9
parts of a bisketimine prepared by the condensation of
isophorone diamine with methyl isobutyl ketone. A storage
stable mixture having a viscosity of 18,000 mPas (2~C) was
obtained. A film applied at room temperature had good abrasion
resistance.
Example 7
195 parts of isocyanate prepolymer II were mixed with 5
parts of glycerol. The mixture had an initial viscosity of
20,000 mPas (22C). A sample was heated to 100C for 70
minutes to accelerate hardening. A tough elastic polymer with
good mechanical properties was obtained.
Example 8
94 parts of isocyanate prepolymer IV were mixed with 6
parts of 1-methyl-3,5-diethyl-phenylenediamine-(2,~). The
solvent-free mixture had an initial viscosity of 80,000 mPas
(22C) and a pot life of 20 minutes. A film applied at room
temperature was pressure dry after about 60 minutes. A tough
3a elastic film with good abrasion resistance was obtained after
aging.
Example 9 (Comparison)
1000 g of the polyester carbonate diol used for the
preparation of isocyanate prepolymer II and 222 g of isophorone
diisocyanate were prepolymerized to a constant isocyanate
Mo3351
- ~ . . . . . .
, . ~ . ..
. . . . -. . .
. .
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20~
content at 100C. The prepolymer obtained had the following
characteristics:
NC0 content = 3.35%
viscosity a~ 22~C = 400,000 mPas
5 monomer content = 2.5%.
The prepolymer had to be diluted to a solids content of
80% with butyl acetate to enable it to be applied.
NC0 content = 2.68%
viscosity at 22~ = 12,000 mPas.
1~9 Parts of the solvent-containing prepolymer were mixed
with 11 parts of l-methyl-3,5-diethyl-phenylenediamine-(2,4)0
The mixture had an initial viscosity of 13,000 mPas (22C) and
a pot life of 15 minutes. A film applied at room temperature
was pressure dry after about 60 minutes.
Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be
understood that such detail is solely for that purpose and that
variations can be made therein by those skilled in the art
without departing from the spirit and scope of the invention
2Q except as it may be limited by the claims.
Mo3351
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: ............ , - .
;: , , :. : . . : -
