U.S. patent application number 09/941793 was filed with the patent office on 2002-05-09 for condensation polymer containing hydroxyalkylamide groups.
This patent application is currently assigned to DSM N.V.. Invention is credited to Rietberg, Johan, Stanssens, Dirk A.W., Van Benthem, Rudolfus A.T.M..
Application Number | 20020055609 09/941793 |
Document ID | / |
Family ID | 19765776 |
Filed Date | 2002-05-09 |
United States Patent
Application |
20020055609 |
Kind Code |
A1 |
Van Benthem, Rudolfus A.T.M. ;
et al. |
May 9, 2002 |
CONDENSATION POLYMER CONTAINING HYDROXYALKYLAMIDE GROUPS
Abstract
The invention relates to a linear or branched polymer containing
ester groups and at least one amidegroup in the backbone, having
hydroxyalkylamide end groups and having a weight average molecular
mass of .gtoreq.800 g/mol. The invention also relates to an
entirely or partly modified polymer. The polymer according to the
invention can for example be obtained by reaction of a cyclic
anhydride and an alkanolamine to form a .beta.-hydroxyalkylamide,
after which a polyesteramide is obtained through polycondensation.
The polymers according to the invention can, for example, be used
in thermosetting powder-paint compositions.
Inventors: |
Van Benthem, Rudolfus A.T.M.;
(Sittard, NL) ; Rietberg, Johan; (Zwolle, NL)
; Stanssens, Dirk A.W.; (Houthalen, BE) |
Correspondence
Address: |
Pillsbury Winthrop LLP
Intellectual Property Group
1600 Tysons Boulevard
McLean
VA
22102
US
|
Assignee: |
DSM N.V.
|
Family ID: |
19765776 |
Appl. No.: |
09/941793 |
Filed: |
August 30, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
09941793 |
Aug 30, 2001 |
|
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09534326 |
Mar 24, 2000 |
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09534326 |
Mar 24, 2000 |
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PCT/NL98/00546 |
Sep 22, 1998 |
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Current U.S.
Class: |
528/271 ;
428/109; 525/438; 525/540; 528/288; 528/332; 528/335; 528/403;
528/422 |
Current CPC
Class: |
Y10T 428/2982 20150115;
C08G 63/6854 20130101; C08G 69/44 20130101; Y10T 428/24091
20150115 |
Class at
Publication: |
528/271 ;
528/288; 528/332; 528/335; 528/403; 528/422; 525/438; 525/540;
428/109 |
International
Class: |
B32B 015/02; G03G
009/00; C08G 069/26 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 1997 |
NL |
1007186 |
Claims
1. A branched condensation polymer containing ester groups and at
least one amide group in the backbone, having at least one
.beta.-substituted .beta.-hydroxyalkylamide end group, having a
hydroxylalkylamide functionality between 2 and 250 and having a
weight average molecular mass of .gtoreq.800 g/mol.
2. Polymer according to claim 1, characterized in that the polymer
contains at least two groups according to formula (I): 29in which
30(cyclo)alkyl, or (C.sub.6-C.sub.10) aryl, B=(C.sub.2-C.sub.24),
optionally substituted, aryl or (cyclo)alkyl aliphatic diradical,
R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 may,
independently of one another, be the same or different, H,
(C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8) (cyclo)alkyl radical
and n=1-4.
3. Polymer according to any one of claims 1-2, characterized in
that the polymer comprises at least two groups according to formula
(II): 31in which 32(C.sub.1-C.sub.24)(cyclo)alkyl or
(C.sub.6-C.sub.10) aryl, B=(C.sub.2-C.sub.24), optionally
substituted, aryl or (cyclo)alkyl aliphatic diradical, and R.sup.1,
R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 may, independently
of one another, be the same or different, H, (C.sub.6-C.sub.10)
aryl or (C.sub.1-C.sub.8)(cyclo)alkyl radical.
4. Condensation polymer according to any one of claims 1-3,
characterized in that the polymer is a polymer according to formula
(III): 33in which: 34(C.sub.1-C.sub.20)(cyclo)alkyl or
(C.sub.6-C.sub.10)aryl, 35B=(C.sub.2-C.sub.24), optionally
substituted, aryl or (cyclo)alkyl aliphatic diradical, 36X.sup.2=H
or X.sup.1 and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and
R.sup.6 may be H, (C.sub.6-C.sub.10) aryl or
(C.sub.10-C.sub.8)(cyclo)alkyl radical or CH.sub.2-OX.sup.2.
5. Condensation polymer according to any one of claims 1-4,
characterized in that the polymer is represented by formula (IV):
37in which: 38(C.sub.1-C.sub.20) (cyclo)alkyl or
(C.sub.6-C.sub.10)aryl. 39or OH, B=(C.sub.2-C.sub.24), optionally
substituted, aryl or (cyclo)alkyl aliphatic diradical, 40X.sup.2=H
or X.sup.1, R.sup.3=H or (C.sub.6-C.sub.10) aryl or
(C.sub.1-C.sub.8)alkyl radical, and R.sup.6=H or (C.sub.6-C.sub.10)
aryl or (C.sub.1-C.sub.8)alkyl radical.
6. Condensation polymer according to any one of claims 1-5,
characterized in that the polymer is a polymer according to formula
(V): 41in which: 42B=(C.sub.2-C.sub.12), optionally substituted,
aryl or (cyclo)alkyl aliphatic diradical, 43X.sup.2=H or X.sup.1,
R.sup.3=(C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8) (cyclo)alkyl
radical and R.sup.6=(C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8)
(cyclo)alkyl radical.
7. Polymer according to any one of claims 2-6, characterized in
that B is a (methyl-)1,2-ethylene, (methyl-)1,2-ethylidene,
1,3-propylene, (methyl-)1,2-cyclohexyl, (methyl-)1,2-phenylene,
1,3-phenylene, 1,4-phenylene, 2,3norbornyl, 2,3-norbornen-5-yl
and/or (methyl-)1,2-cyclohex-4-enyl radical.
8. Polymer according to any one of claims 1-7, characterized in
that the weight average molecular mass is between 800 and 50,000
g/mol, the number average molecular mass is between 600 and 10,000
and the hydroxyalkylamide functionality is between 2 and 250.
9. Polymer according to any one of claims 1-8 obtainable by
polycondensation of a mono- and/or bis-.beta.-hydroxyalkylamide of
a bivalent carboxylic acid.
10. Process for the preparation of a polymer according to any one
of claims 1-9, characterized in that a cyclic anhydride reacts with
an alkanolamine to form a hydroxylalkylamide, after which the
polymer is obtained through polycondensation.
11. Process for the preparation of a polymer according to any one
of claims 1-9, characterized in that an alkanolamine reacts with a
compound containing an acid group and an activated acid group,
after which the polymer is obtained through polycondensation.
12. Process for the preparation of a polymer according to any one
of claims 1-9, characterized in that a cyclic anhydride reacts with
an alcohol, after which the reaction product obtained reacts in
situ with an alkanolamine and the polymer is subsequently obtained
through polycondensation.
13. Process according to any one of claims 10-12, characterized in
that the alkanolamine is a .beta.-alkyl-substituted
.beta.-hydroxyalkylamine.
14. Modified polymer that can be obtained through a reaction
between a polymer according to any one of formulas (III), (IV) or
(V) with a monomer, oligomer or polymer containing reactive groups
that can react with hydroxyalkylamine.
15. Modified polymer according to any one of formulas (III), (IV)
or (V) in which 44in which 45is derived from a monomeric,
oligomeric or polymeric monofunctional carboxylic acid.
16. Powder-paint binder composition containing a polymer according
to any one of claims 1-9 or 15-16 or a polymer obtained according
to any one of claims 10-14.
17. Binder composition according to claim 17 which additionally
contains a crosslinker comprising at least one linear or branched
aliphatic chain with 5-26 carbon atoms and having an epoxy
functionality of more than 1, with the proviso that the epoxy
groups are carried on the at least one aliphatic chain.
18. Powder paint composition comprising a binder composition
according to any one of claims 17-18.
19. Powder coating obtained by curing of a powder paint according
to claim 19.
20. Entirely or partly coated substrate, characterized in that the
coating is a powder coating according to claim 20.
Description
[0001] The invention relates to a linear or branched condensation
polymer containing ester groups and at least one amide group in the
backbone, having at least one hydroxyalkylamide endgroup and having
a weight average molecular mass of .gtoreq.800 g/mol.
[0002] Preferably, the polymer contains at-least two groups
according to formula (I) 1
[0003] in which 2
[0004] (C.sub.1-C.sub.20)(cyclo)alkyl, or (C.sub.6-C.sub.10)
aryl,
[0005] B=(C.sub.2-C.sub.24), optionally substituted, aryl or
(cyclo)alkyl aliphatic diradical,
[0006] R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 may,
independently of one another, be the same or different, H,
(C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8)(cyclo)alkyl radical
and
[0007] n=1-4.
[0008] More preferably the polymer contains at least two groups
according to formula (II): 3
[0009] in which 4
[0010] (C.sub.1-C.sub.20)(cyclo)alkyl, or (C.sub.6-C.sub.10)
aryl,
[0011] B=(C.sub.2-C.sub.24), optionally substituted, aryl or
(cyclo)alkyl aliphatic diradical, and
[0012] R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 may,
independently of one another, be the same or different, H,
(C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8)(cyclo)alkyl
radical.
[0013] According to a further preferred embodiment, the polymer
containing hydroxyalkylamide groups is a polymer according to
formula (III): 5
[0014] in which: 6
[0015] (C.sub.1-C.sub.20)(cyclo)alkyl or (C.sub.6-C.sub.10) aryl
7
[0016] or OH,
[0017] B=(C.sub.2-C.sub.24), optionally substituted, aryl or
(cyclo)alkyl aliphatic diradical, 8
[0018] X.sup.2=H or X.sup.1 and
[0019] R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 may,
independently of one another, be the same or different, H,
(C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8)(cyclo)alkyl radical or
CH.sub.2-OX.sup.2.
[0020] In formulas (I), (II) and (III) R groups may together or
with neighbouring carbon atoms form part of a cycloalkyl group.
[0021] According to another preferred embodiment of the invention,
the polymer containing .beta.-hydroxyalkylamide groups is a polymer
according to formula (IV): 9
[0022] in which: 10
[0023] (C.sub.1-C.sub.20)(cyclo)alkyl or (C.sub.6-C.sub.10) aryl,
11
[0024] or OH,
[0025] B=(C.sub.2-C.sub.20), optionally substituted, aryl or
(cyclo)alkyl aliphatic diradical, 12
[0026] X.sup.2=H or X.sup.1,
[0027] R.sup.3=H or (C.sub.6-C.sub.10) aryl or
(C.sub.1-C.sub.8)alkyl radical and
[0028] R.sup.6=H or (C.sub.6-C.sub.10) aryl or
(C.sub.1-C.sub.8)alkyl radical.
[0029] The weight average molecular mass of the polymer according
to the invention is generally between 800 and 50,000, and
preferably between 1000 g/mol and 25,000 g/mol.
[0030] The number average molecular mass is generally between 600
and 10,000 and preferably between 700 and 4000.
[0031] The hydroxyalkylamide functionality is generally between 2
and 250 and preferably between 5 and 50.
[0032] Functionality is the average number of reactive groups of
the specific type per molecule in the polymer composition.
[0033] According to another preferred embodiment of the invention
the polymer's hydroxyalkylamide functionality of the polymer is
.gtoreq.5 and the polymer containing .beta.-hydroxyalkylamide
groups is a polymer represented by formula (V): 13
[0034] in which: 14
[0035] B=(C.sub.2C.sub.12), optionally substituted, aryl or
(cyclo)alkyl aliphatic diradical, 15
[0036] X.sup.2=H or X.sup.1,
[0037] R.sup.3=H or (C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8)
(cyclo)alkyl radical and
[0038] R.sup.6=H or (C.sub.6-C.sub.10) aryl or (C.sub.1-C.sub.8)
(cyclo)alkyl radical Preferably R.sup.3 and R.sup.6 are
(C.sub.1-C.sub.4) alkyl.
[0039] According to another preferred embodiment of the invention
R.sup.3 and R.sup.6 are methyl or ethyl.
[0040] B may be saturated or unsaturated.
[0041] B may be substituted with for example a (C.sub.1-C.sub.26)
alkyl group, which may be saturated or unsaturated; preferably
C.sub.1 is used.
[0042] B may be for example a (methyl-)1,2-ethylene,
(methyl-)1,2-ethylidene, 1,3-propylene, (methyl-)1,2-cyclohexyl,
(methyl-)1,2-phenylene, 1,3-phenylene, 1,4-phenylene,
2,3-norbornyl, 2,3-norbornen-5-yl and/or (methyl-)1,2
cyclohex-4-enyl radical.
[0043] Depending on the starting monomers chosen, the variables B,
R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 in the
molecule or mixture of molecules can be selected to be the same or
different per variable.
[0044] The polymer composition according to the invention is
generally a composition comprising higher and lower oligomers,
which usually contains less than 50 wt. %, preferably less than 30
wt. %, of oligomers having a molecular weight smaller than 600.
[0045] The polyesteramide according to the invention can for
example be obtained through polycondensation of mono- and/or
bis-hydroxyalkylamides of bivalent carboxylic acids.
[0046] The monohydroxyalkylamide of a bivalent carboxylic acid
generally has the formula (VI): 16
[0047] and the bishydroxyalkylamide of a bivalent carboxylic acid
generally can be represented by formula (VII): 17
[0048] wherein
[0049] R.sup.1, R R.sup.3 and R.sup.4 may, independently of one
another, be the same or different, H, (C.sub.6-C.sub.10) aryl or
(C.sub.1-C.sub.8)(cyclo)alkyl radical.
[0050] Consequently a lineair polymer according to the invention
generally comprises the amide and the ester groups alternating
along the chain as follows:
E-A-E-A-A-E-A-E-A-E
[0051] wherein a diamide is coupled with alternating ester
(E)--amide (A) groups.
[0052] A branched polymer according to the invention generally
comprises the amide and the ester groups alternating along the main
and side chains as follows: 18
[0053] wherein a diamide is coupled with alternating ester
(E)--amide (A) groups.
[0054] In the branched polymers according to the invention
(.beta.)-hydroxyalkylamide groups can be present both as an
endgroup 19
[0055] and as a pendant side chain group 20
[0056] Generally, the molar amount of amide bounds in the chain is
higher than the amount of ester bounds.
[0057] The polymer according to the invention comprises at least
60% by weight of the products represented by the formulas
(III)-(V).
[0058] Due to side reactions during the preparation of the polymer
it is possible that the composition according to the invention
comprises also for example secundary amine groups having the
formula (VIII): 21
[0059] wherein:
[0060] R.sup.1, R.sup.2, R.sup.3 and R.sup.4 may, independently of
one another, be the same or different, H, (C.sub.6-C.sub.10) aryl
or (C.sub.1-C.sub.8) (cyclo)alkyl radical.
[0061] The polymer according to the invention can, also be obtained
in a one-step procedure by reacting a cyclic anhydride and an
alkanolamine, at a temperature between for example about 20.degree.
C. and about 100.degree. C., to form a hydroxyalkylamide, after
which, at a temperature between, for example, 120.degree. C. and
250.degree. C., a polyesteramide is obtained through
polycondensation with water being removed through distillation.
[0062] The reaction can take place without a solvent, but also in
water or in an organic solvent.
[0063] The removal of water through distillation can take place at
a pressure higher than 1 bar, in a vacuum or azeotropically.
[0064] Preferably, the cyclic anhydride is an anhydride according
to formula (IX): 22
[0065] in which B has the meaning specified above.
[0066] Examples of suitable cyclic anhydrides include phthalic
anhydride, tetrahydrophthalic anhydride, naphtalenic dicarboxylic
anhydride, hexahydrophthalic anhydride,
5-norbornene-2,3-dicarboxylic anhydride,
norbornene-2,3-dicarboxylic anhydride, naphtalenic dicarboxylic
anhydride, 2-dodecene-1-yl-succinic anhydride, maleic anhydride,
(methyl)succinic anhydride, glutaric anhydride, 4-methylphthalic
anhydride, 4-methylhexahydrophthalic anhydride,
4-methyltetrahydrophthali- c anhydride and the maleinised
alkylester of an unsaturated fatty acid.
[0067] Preferably the alkanol is an alkanolamine according to
formula (X): 23
[0068] in which: 24
[0069] (C.sub.1-C.sub.20)(cyclo)alkyl, R.sup.1, R.sup.2, R.sup.3,
R.sup.4, R.sup.5 and R.sup.6 may, independently of one another, be
the same or different, H, (C.sub.6-C.sub.10) aryl or
(C.sub.1-C.sub.8)(cyclo)alkyl radical or CH.sub.2OH and n=1-4.
[0070] More preferably n=1. The alkanolamine may be a
monoalkanolamine, a dialkanolamine, a trialkanolamine or a mixture
hereof.
[0071] If monoalkanolamines are used in one of the possible polymer
syntheses, linear polymers with a functionality of 2 can be
obtained. Depending on the application desired, a linear or an
entirely or partly branched polymer can be chosen, in which case
the degree of branching can be set via the alkanolamines
chosen.
[0072] If a highly branched structure with a high functionality is
desired, di- or trialkanolamines are used as the starting
compound.
[0073] Examples of suitable mono-.beta.-alkanolamines include
ethanolamine, 1-(m)ethyl ethanolamine, n-butyl ethanolamine,
1-(m)ethyl isopropanolamine, isobutanolamine,
.beta.-cyclohexanolamine, n-butyl isopropanolamine and
n-propanolamine.
[0074] Examples of suitable di-.beta.-alkanolamines are
3-amino-1,2-propanediol, 2-amino-1,3-propanediol diisobutanolamine
(bis-2-hydroxy-1-butyl)amine), di-.beta.-cyclohexanolamine and
diisopropanolamine (bis-2-hydroxy-1-propyl)amine).
[0075] A suitable trialkanolamine is, for example,
tris(hydroxymethyl)amin- omethane.
[0076] Preferably a .beta.-alkyl-substituted
.beta.-hydroxyalkylamide is used. Examples are (di)
isopropanolamine, cyclohexyl isopropanolamine, 1-(m)ethyl
isopropanolamine, (di)isobutanolamine, di-.beta.-cyclohexanola-
mine and/or n-butyl isopropanolamine.
[0077] This results in polymer compositions with improved
resistance to hydrolysis.
[0078] Most preferable are diisopropanolamine and
diisobutanolamine.
[0079] The anhydride: alkanolamine equivalent ratio is generally
between 1.0:1.0 and 1.0:1.8. Preferably, this ratio is between
1:1.05 and 1:1.5.
[0080] The compound according to the invention can also be obtained
via a reaction between an alkanolamine, as for example described
above, and a compound containing one acid group and one activated
acid group, after which a polyesteramide is obtained through
polycondensation.
[0081] The compound containing an acid group and an activated acid
group is preferably a compound according to formula (XI): 25
[0082] in which
[0083] B has the meaning specified above and 26
[0084] in which R.sup.7 is a (C.sub.1-C.sub.12) branched or linear
alkyl group.
[0085] Examples of suitable compounds containing one acid group and
one activated acid group are alkyl esters, such as, for example,
mono(m)ethyl adipate and mono(m)ethyl sebacate, anhydrides and
thioesters.
[0086] The compound according to the invention can also be obtained
via a reaction between a cyclic anhydride, as for example described
above, and an alcohol, after which the reaction product obtained
reacts in situ with an alkanolamine and a polyesteramide is
subsequently obtained through polycondensation.
[0087] Examples of suitable alcohols are (C.sub.1-C.sub.10)
alcohols.
[0088] Preferably, methanol or ethanol is used.
[0089] In addition to hydroxyalkylamide groups, the polymer may
also contain carboxyl groups, in amounts of between 0.01 and 2.0 mg
equivalent/gram of polymer. The number of carboxylic acids present
in the polymer can be controlled via the anhydride/alkanolamine
ratio and via the degree of conversion. If an alkanolamine excess
is used and the polycondensationreaction is (almost) complete, less
than 0.2 mg equivalent acid/gram of polymer is usually present. If
carboxyl groups are present, they may in a subsequent step react
with compounds containing one or more groups that can react with
carboxylic acid, such as for example epoxy groups or
.beta.-hydroxyalkylamide groups. The amount of carboxylic acid is
preferably as low as possible, for example between 0.01 and 0.2 mg
equivalent/gram of polymer.
[0090] The degree of branching and the functionality of the polymer
are dependent on the starting materials and the molecular weight of
the polymer. A molecular weight higher than 2000 and the use of di-
and/or trialkanolamines generally lead to highly branched
structures with a functionality of .gtoreq.10.
[0091] Due to the presence in amounts of less than 10% by weight
(of the total amount of anhydrides) of bis- and dianhydrides
instead of the anhydrides according to formula (IX) it is possible
that the polymer does not comprise only products according to
formulas (III)-(V)
[0092] The invention also relates to entirely or partly modified
polymers.
[0093] The modification can for example take place via a reaction
between the polymer according to any one of formulas (III), (IV) or
(V) with a monomer, oligomer or polymer containing reactive groups
that can react with the hydroxyalkylamide.
[0094] Examples of suitable reactive groups include carboxyl
groups, carboxylic esters, carboxylic anhydrides, epoxy groups,
alkoxysilane groups, isocyanate groups, acid chloride groups,
epoxychlorohydrine groups, amine groups, phenolic groups,
methylolated amidegroups and combinations hereof.
[0095] Preferably the monomer, oligomer or polymer contains only
one group that can react with hydroxylalkylamide, as a result of
which no crosslinking takes place during the modification.
[0096] The polymer according to formula (III), (IV) or (V) has
preferably been modified with a compound containing a carboxylic
acid group.
[0097] A modified polymer can for example be represented by one of
the formulas (III), (IV) or (V) in which 27
[0098] in which 28
[0099] is derived from a monomeric, oligomeric or polymeric
monofunctional carboxylic acid.
[0100] Suitable carboxylic acids are, for example, saturated
aliphatic (C.sub.1-C.sub.26) acids, unsaturated (C.sub.1-C.sub.20)
fatty acids, aromatic acids and .alpha.,.beta.-unsaturated
acids.
[0101] Examples of suitable .alpha., .beta.-unsaturated acids are
(meth)acrylic acid, crotonic acid and monoesters or monoamides of
itaconic acid, maleic acid, 12-hydroxystearic acid, polyether
carboxylic acid, and fumaric acid.
[0102] Suitable saturated aliphatic acids are for example acetic
acid, propionic acid, butyric acid, 2-ethyl hexanoic acid, laurylic
acid and stearic acid.
[0103] Suitable aromatic acid are for example benzoic acid and
tertiairy butyl benzoic acid.
[0104] Z can be chosen from, for example, a saturated or
unsaturated (C.sub.1-C.sub.40) alkyl or aromatic group, a polymer
or an oligomer. Examples of suitable polymers are polyesters,
polyethers and poly(capro)lactones.
[0105] Z can be substituted with for example ester groups, ether
groups, amide groups and alcohol groups.
[0106] The modified polymer may consist of the same or different Z
groups.
[0107] The branched polymer according to the invention can also
react with a diisocyanate, after which the isocyanate-functional
polymer obtained reacts with a compound capable of reacting with
isocyanates. As the diisocyanate use is preferably made of a
compound containing two or more isocyanate groups with different
reactivities. This is preferably an aliphatic diisocyanate with one
sterically more accessible isocyanate group bound to a primary
carbon atom and one sterically less accessible isocyanate group
bound to a tertiary carbon atom.
[0108] Examples of suitable diisocyanates are
1,4-diisocyanato-4-methyl-pe- ntane,
1,5-diisocyanato-5-methylhexane,
3(4)-isocyanatomethyl-1-methylcycl- ohexylisocyanate,
1,6-diisocyanato-6-methyl-heptane,
1,5-diisocyanato-2,2,5-trimethylhexane and
1,7-diisocyanato-3,7-dimethylo- ctane, and
1-isocyanato-1-methyl-4-(4-isocyanatobut-2-yl)-cyclohexane,
1-isocyanato-1,2,2-trimethyl-3-(2-isocyanato-ethyl)-cyclopentane,
1-isocyanato-1,4-dimethyl-4-isocyanatomethyl-cyclohexane,
1-isocyanato-1,3-dimethyl-3-isocyanatomethyl-cyclohexane,
1-isocyanatol-n-butyl-3-(4-isocyanatobut-1-yl)-cyclopentane and
1-isocyanato-1,2-dimethyl-3-ethyl-3-isocyanatomethyl-cyclopentane,
respectively.
[0109] The preferred isocyanates are
3(4)-isocyanato-methyl-1-methylcycloh- exylisocyanate (IMCI) and
isophorone diisocyanate.
[0110] Monomers, oligomers and polymers can all be used as the
compounds that can react with isocyanate groups. Such compounds
contain reactive groups that can form a chemical bond with
isocyanate groups.
[0111] Examples of suitable reactive groups are alcohols and amine
groups.
[0112] Examples of suitable compounds are
hydroxyethyl(meth)acrylate, hydroxy(C.sub.2-C.sub.12)alkyl vinyl
ether, 4-hydroxybutyl(meth)acrylate, aminopropyl vinyl ethers,
aminoalkyl vinyl ether, aminopropyl-tri(m)ethox- ysilane and
aminoalkyltrialkoxysilane.
[0113] Preferably the diisocyanate, for example IMCI, is combined
with a selective catalyst, as a result of which no chain
lengthening or crosslinking will take place.
[0114] As the catalyst use can be made of an ionogenic metal
complex based on a metallic element from any one of groups III, IV
or VII of the Periodic System with exchangeable counterions.
Examples of suitable catalysts are titanium (IV) butoxide,
zirconium (IV) acetylacetonate, zirconium (IV) butoxide, tin (IV)
acetate, manganese (III) acetylacetonate, titanium (IV)
isopropoxide, zirconium (IV) 2-ethylhexanoate and tin (IV)
chloride.
[0115] The modified and the unmodified polymers can be very widely
used in technically different fields, both in thermosetting and in
thermoplastic applications. Examples are powder-paint compositions,
coating systems based on water or solvent, can- or coil-coating
systems, radiation-curable coating compositions, alkyd resins for
coatings, unsaturated resins for construction purposes (for example
putties, sealants, castings, compounds and molding compounds),
inks, toner, film rormers for glass fibre sizings, adhesives, hot
melts and in rubber compositions.
[0116] Unmodified or partly modified polymers according to the
invention will generally be used in powder-paint systems, in can-
or coil-coating systems or in solvent-based coating systems.
[0117] If the modification has been realized with the aid of for
example fatty acids, the polymers according to the invention can be
used as airdrying systems.
[0118] A modification with radically curable compounds offers
possibilities in the technical fields of radiation-curable coatings
and construction resins.
[0119] Considering the many possibilities of modification of the
polymer according to the invention, modification can be directed at
any of a wide range of technical applications.
[0120] The polymers according to the invention can be used in
thermosetting powder-paint compositions. Preferably use is made of
the polymers containing .beta.-hydroxyalkylamide groups.
[0121] Thermosetting powder paints have a better resistance to
chemicals than thermoplastic powder paints. As a result of this,
intensive efforts have for a long time been made to develop
crosslinkers and polymers for thermosetting powder coatings.
Attempts are still being made to find binder compositions for
thermosetting powder paints with a good flow behaviour, good
storage stability and a good reactivity. A thermosetting
powder-paint binder composition generally contains more than 50 wt.
% polymer and less than 50 wt. % crosslinker.
[0122] The polymer according to the invention can be used in a
powder-paint composition as a polymer and as a crosslinker.
[0123] The glass transition temperature (Tg) of the polymer
according to the invention lies between 0.degree. C. and
150.degree. C., preferably between 50.degree. C. and 110.degree.
C., depending on the selected starting materials and the molecular
weight.
[0124] Preferably a compound according to any one of formulas (I),
(II), (III), (IV) or (V) is used in powder-paint compositions. It
is also possible to use a polymer in which up to for example 50 wt.
%, preferably less than 30 wt. %, of the hydroxyalkylamide groups
are modified.
[0125] A coating that ultimately obtained with a powder paint must
meet many varying requirements. Various systems are known. Some
systems release volatile components during the curing. These
systems present the drawback that they form coatings with bubbles
and/or that undesirable emissions are released. As far as the
latter is concerned, the volatile component, if organic in origin,
may cause undesirable environmental or health problems. It has
moreover been found that all the desired properties of the powder
paint or powder coating are not always realized.
[0126] Systems comprising hydroxyalkylamide crosslinkers, such as
for example according to EP-A-322834, contain bubbles above a layer
thickness limit of about 100 .mu.m as a result of the reaction
water released.
[0127] In other systems use is made of polyesters and the usual
crosslinkers containing an epoxy group. No volatile components are
generally released from these systems. However, the use of
bisphenol-A-epoxy resins in the so-called hybrid systems results in
coatings that exhibit a relatively great extent of yellowing and
powdering when exposed to UV light, while the frequently used
triglycidylisocyanurate (TGIC) crosslinker is toxicologically
suspect.
[0128] It has been found that use of the polymer according to the
invention as the crosslinker in binder compositions for powder
paints results in a combination of highly desirable properties such
as for instance good flow behaviour and good resistance to
chemicals, desired gloss without bubble formation at the surface up
to and including layer thicknesses of at least 120 .mu.m, a high
resistance to scratching, good mechanical properties, good powder
stability, good weather resistance and good colour stability of the
powder coating.
[0129] It is surprising that use of the highly functional
crosslinkers according to the invention leads to good flow
behaviour, because generally a crosslinker having a functionality
higher than, for example, 6 results in reduced flow behaviour.
[0130] Depending on the final application desired, the crosslinker
according to the invention described above can also be used in
combination with another crosslinker, such as for example
triglycidyl isocyanurate (TGIC), polybisphenol-A-epoxides such as,
for instance, the various Epikote.TM. grades, compounds containing
(blocked) isocyanate groups, such as for example the
caprolactam-blocked isophorone diisocyanate trimer, crosslinkers
containing .beta.-hydroxyalkylamide groups such as for example
Primid XL 522.TM. (Rohm and Haas) and/or polyfunctional oxazolines.
The weight ratio between the crosslinkers can be selected depending
on the final application.
[0131] The crosslinker according to the invention is preferably
combined with a crosslinker comprising at least one linear or
branched aliphatic chain with 5-26 carbon atoms and having an epoxy
functionality of more than 1, with the proviso that the epoxy
groups are carried on the at least one aliphatic chain. These
crosslinkers are described in EP-A-600546 and include, for example,
epoxidized oils in which the oil is linseed oil, soybean oil,
safflower oil, oiticica oil, carraway seed oil, rapeseed oil,
castor oil, dehydrated castor oil, cottonseed oil, wood oil,
vernonia oil (a natural oil), sunflower oil, peanut oil, olive oil,
soyleaf oil, maize oil, fish oil such as, for instance, herring or
sardine oil, and non-cyclic terpene oils.
[0132] The epoxidized oil is preferably epoxidized soybean oil
and/or epoxidized linseed oil.
[0133] As the crosslinker, a powder-paint-binder composition may
contain the polymer according to the invention and as the polymer a
polymer containing carboxyl groups or containing anhydride
groups.
[0134] A polyester, a polyacrylate, a polyether (such for example a
polyether based on bisphenol or a phenol-aldehyde novolak), a
polyurethane, a polycarbonate, a trifluoroethylene copolymer or a
pentafluoropropylene copolymer, a polybutadiene, a polystyrene or a
styrene maleic anhydride copolymer can for example be chosen as the
polymer.
[0135] Generally, polymers having an acid value higher than 40 mg
KOH/gram resins are applied because a relatively high acid value
results in better reactivity with the polymer according to the
invention.
[0136] The molecular weight (Mn) of this polymer is usually higher
than 800, but preferably higher than 1500. The polymer must flow
well at temperatures between 100.degree. C. and 200.degree. C. and
therefore has a molecular weight (Mn) that is lower than
approximately 10,000, preferably lower than approximately 7000.
[0137] This polymer generally has a viscosity at 158.degree. C.
that is lower than 8000 dpas. The viscosity will usually be higher
than 100 dpas. The viscosity can advantageously vary from
approximately 300 to approximately 5000 dpas. The viscosity used
here was measured according to the Emila method described by Misev
in Powder Coatings; Chemistry and Technology, pages 287-288
(1991).
[0138] The Tg of this polymer is generally higher than
approximately 20.degree. C., preferably higher than 30.degree. C.,
and may be higher than 40.degree. C. The polymer's Tg is usually
lower than 120.degree. C. because otherwise the binder composition
may become somewhat difficult to prepare. As already indicated
above, the choice of the polymer's Tg can be based on the Tg
recommended for the binder composition.
[0139] If use is made of polymers having only terminal groups that
can react with a hydroxyalkylamide functionality, the polymer has
an average functionality (capable of reacting with the
hydroxyalkylamide groups) of more than 1.6, preferably more than 2.
The polymer generally has an average functionality of less than 10,
preferably less than approximately 6. If use is made of
polymers--such as polyacrylates--with appended functional groups,
the average functionality will be higher than approximately 1.6,
and preferably higher than 2. Such a polymer generally has an
average functionality of less than 8, preferably less than 4.
[0140] Most preferable of the suitable polymers are polyesters and
polyacrylates.
[0141] With the polymers described various properties can be
obtained in the binder and in the powder coating itself.
Polyacrylates are highly resistant to yellowing and to weather
influences. The polyacrylates that can be used as the polymer may
be based on (meth)acrylic acid, methyl(meth)acrylate,
ethyl(meth)acrylate, butyl(meth)acrylate, propyl(meth)acrylate,
2-ethylhexyl(meth)acrylate, cyclohexyl(meth)acrylat- e,
decyl(meth)acrylate, isodecyl(meth)acrylate, benzyl(meth)acrylate
and hydroxyalkyl(meth)acrylates such as hydroxyethyl and
hydroxypropyl(meth)acrylate and/or glycidyl esters or glycidyl
ethers of alkyl(meth)acrylates.
[0142] The polyacrylates can be obtained via known processes. In
these processes use can be made of comonomers such as for instance
styrene, maleic acid or maleic anhydride and of small amounts of
ethylene, propylene and acrylonitrile. Other vinyl or alkyl
monomers, such as octene, triallyl isocyanurate and diallyl
phthalate, can be added in small amounts.
[0143] A polyacrylate containing acid groups is generally obtained
through copolymerization of the desired amount of acid, such as for
example (meth)acrylic acid, maleic acid or fumaric acid.
[0144] The polyacrylate's viscosity usually lies between 100 and
8000 dPas (measured at 158.degree. C.; Emila).
[0145] Polyacrylates are described in the patents U.S. Pat. No.
3,752,870, U.S. Pat. No. 3,787,340 and U.S. Pat. No. 3,758,334 and
in the British patent 1,333,361, and what is disclosed in said
patents is included herein by means of this reference.
[0146] The polyurethanes that can be used as the polymer that can
react with .beta.-hydroxyalkylamide groups include for example also
the polyurethanes terminated with an acid group and a (blocked)
isocyanate group.
[0147] Polyesters are usually based on the residues of aliphatic
polyalcohols and polycarboxylic acids.
[0148] The polycarboxylic acids are generally chosen from the group
consisting of aromatic and cycloaliphatic polycarboxylic acids
because these acids usually have a Tg-raising effect on the
polyester. In particular, use is made of dibasic acids. Examples of
polycarboxylic acids are isophthalic acid, terephthalic acid,
hexahydroterepthalic acid, 2,6-naphthalene dicarboxylic acid and
4,4-oxybisbenzoic acid and, subject to availability, their
anhydrides, acid chlorides or lower alkyl esters, such as for
example the dimethyl ester of naphthalene dicarboxylic acid.
Although not required, the carboxylic acid component generally
contains at least approximately 50 mol. %, preferably at least
approximately 70 mol. %, isophthalic acid and/or terephthalic
acid.
[0149] Other suitable aromatic cycloaliphatic and/or acyclic
polycarboxylic acids are for example 3,6-dichlorophthalic acid,
tetrachlorophthalic acid, tetrahydrophthalic acid,
hexahydroterephthalic acid, hexachloroendomethylene
tetrahydrophthalic acid, phthalic acid, azelaic acid, sebacic acid,
decanedicarboxylic acid, adipic acid, succinic acid, trimellitic
acid and maleic acid. These different carboxylic acids can be used
in amounts of at most 50 mol. % of the total amount of carboxylic
acids. These acids can be used as such or, subject to availability,
in the form of their anhydrides, acid chlorides or lower alkyl
esters.
[0150] Hydroxycarboxylic acids and/or optionally lactones can also
be used, for example 12-hydroxystearic acid, hydroxypivalic acid
and .epsilon.-caprolactone. If so desired, monocarboxylic acids,
such as benzoic acid, tert.-butylbenzoic acid, hexahydrobenzoic
acid and saturated aliphatic monocarboxylic acids can be used in
smaller amounts.
[0151] The polyalcohols, in particular diols, that can be caused to
react with the carboxylic acids to obtain the polyester include
aliphatic diols such as for example ethylene glycol,
propane-1,2-diol, propane-1,3-diol, butane-1,2-diol,
butane-1,4-diol, butane-1,3-diol, 2,2-dimethylpropanediol-1,3
(=neopentyl glycol), hexane-2,5-diol, hexane-1,6-diol,
2,2-bis-(4-hydroxy-cyclohexyl)-propane (hydrogenated bisphenol-A),
1,4-dimethylolcyclohexane, diethylene glycol, dipropylene glycol
and 2,2-bis[4-2-hydroxylethoxy)-phenyl]propane and the
hydroxypivalic ester of neopentyl glycol.
[0152] Small amounts, such as less than approximately 4 wt. %, but
preferably less than 2 wt. %, of trifunctional alcohols or acids
can be used to obtain branched polyesters. Examples of suitable
polyols and polyacids are glycerol, hexanetriol, trimethylolethane,
trimethylolpropane, tris-(2-hydroxyethyl)-isocyanurate and
trimellitic acid.
[0153] Tetrafunctional monomers are usually not preferred, because
they can cause excessive branching or gelling, although it is
possible to use them in very small amounts. Examples of suitable
polyfunctional alcohols and acids are sorbitol, pentaerythritol and
pyromellitic acid. Trifunctional monomers are however preferred for
synthesizing branched polyesters.
[0154] The coating properties can be influenced via for example the
choice of diol. If for example good weather resistance is required,
the alcohol component preferably contains at least 70 mol. %
neopentyl glycol, 1,4-dimethylolhexane and/or hydrogenated
bisphenol-A. Caprolactone and hydropivalic acid can also be used if
good weather resistance is required.
[0155] The polyesters are prepared via the usual processes, through
esterification or trans-esterification, optionally in the presence
of the usual esterification catalysts such as for example dibutyl
tin oxide or tetrabutyl titanate. The preparation conditions and
the COOH/OH ratio can be chosen so that end products having an acid
number or hydroxyl value that lies within the desired range of
values are obtained.
[0156] A carboxylic-acid-functional polyester is preferably
prepared in a series of steps. In the last step thereof an aromatic
or, preferably, aliphatic acid is esterified so that an
acid-functional polyester is obtained. As known to a person skilled
in the art, terephthalic acid is in a first step caused to react in
the presence of excess diol. Such reactions result in a
substantially hydroxyl-functional polyester. In a second or
subsequent step an acid-functional polyester is obtained by causing
further acid to react with the product of the first step. Further
acids are for example isophthalic acid, adipic acid, succinic
anhydride, 1,4-cyclohexanedicarboxylic acid and trimellitic
anhydride.
[0157] Preferably trimellitic anhydride is used at a temperature of
170-200.degree. C., because then a polyester with a relatively
large number of trimellitic acid terminal groups is obtained, as a
result of which the reactivity of the binder system is increased
and better coating properties are obtained.
[0158] The polyester may be a crystalline polyester, but amorphous
polyesters are preferred. Mixtures of crystalline and amorphous
polyesters can also be used. Amorphous polyesters have a viscosity
that generally lies within a range from 100 to 8000 dPas (measured
at 158.degree. C., Emila). Crystalline polyesters usually have a
lower viscosity in the range from approximately 2 to approximately
200 dPas.
[0159] If the polyester contains groups that can react with
carboxylic acid, the polyester's acid number is chosen so that the
desired amount of crosslinker can be used. The acid number is
preferably higher than 10 and more preferably higher than 40.
[0160] The polyester's Tg is chosen so that the Tg of the
polyester-crosslinker mixture lies between for example 30.degree.
C. and 80.degree. C., as a result of which powder paints or binders
prepared from them are physically stable at room temperature.
Combinations of polyester and crosslinker having a lower Tg can
optionally be used in the preparation of a powder coating
composition. To retain the powder stability, such powders are
however stored in cooled condition.
[0161] The selection of the polymer: crosslinker weight ratio
depends on the desired final application and this ratio will
generally be between 60:40 and 90:10, preferably between 75:25 and
85:15.
[0162] If the polymer according to the invention is used as a resin
in powder-paint compositions, compounds containing two or more
functional groups that can react with .beta.-hydroxyamide groups
can be used as the crosslinker. Examples of such groups are
anhydrides, carboxylic acids, carboxylic esters, epoxides,
isocyanates and alkoxysilanes. Preferably anhydride groups,
carboxylic acids and blocked isocyanates are used. Examples are
adipic acid, decanedicarboxylic acid, trimellitic anhydride,
phthalic acid or phthalic anhydride, tetrahydrophthalic acid or
tetrahydrophthalic anhydride, hexahydrophthalic acid or
hexahydrophthalic anhydride and IPDI-trimer or HDI-trimer,
optionally blocked with caprolactam or triazole.
[0163] The preparation of thermosetting powder coatings in general
and the chemical reactions for curing powder paints to form cured
coatings are described by Misev in Powder Coatings, Chemistry and
Technology (1991, John Wiley) on pp. 42-54, pp. 148 and 224-226. A
thermosetting binder composition is generally defined as the
resinous part of the powder paint consisting of polymer and
crosslinker.
[0164] If so desired, the usual additives can be used in the binder
composition and in the powder-paint system according to the
invention, such as for example pigments, fillers, degassing agents,
flow agents and stabilizers. Suitable pigments are for example
inorganic pigments, such as for example titanium dioxide, zinc
sulphide, iron oxide and chromium oxide, and also organic pigments
such as for example azo compounds. Suitable fillers are for example
metal oxides, silicates, carbonates and sulphates.
[0165] Primary and/or secondary antioxidants, UV stabilizers such
as quinones, (sterically hindered) phenolic compounds,
phosphonites, phosphites, thioethers and HALS compounds (hindered
amine light stabilizers) can for example be used as
stabilizers.
[0166] Examples of degassing agents are benzoin and cyclohexane
dimethanol bisbenzoate. The flow agents include for example
polyalkylacrylates, fluorohydrocarbons and silicone fluids. Other
suitable additives are for example additives for improving
tribocharging, such as sterically hindered tertiary amines that are
described in EP-B-371528.
[0167] Powder paints according to the invention can be applied in
the usual manner, for example by electrostatically spraying the
powder onto an earthed substrate and curing the coating by exposing
it to heat at a suitable temperature for a sufficient length of
time. The applied powder can for example be heated in a gas oven,
an electric oven or with the aid of infrared radiation.
[0168] Thermosetting coatings of powder-paint (coating)
compositions intended for industrial applications are described
further in a general sense in Powder Coatings, Chemistry and
Technology, Misev, pages 141-173 (1991).
[0169] Compositions according to the present invention can be used
in powder paints for use on, for example, metal, wooden and plastic
substrates. Examples are industrial coatings, coatings for machines
and tools, household applications and parts of buildings. The
coatings are also suitable for use in the automotive industry for
coating parts and accessories.
[0170] DE-A-19703952 discloses a copolyester containing
.beta.-hydroxyalkylamide groups as endgroups. The polyester polymer
backbone does not comprise amide groups. The copolyester is
prepared in a three step process by mixing a hydroxy polyester with
a polycarboxylic acid dialkyl ester to form an alkylester group
containing copolyester followed by reaction with an aminoalcohol.
In contrast, the polymer according to the invention is a
polyesteramide having amide and ester groups along the backbone in
addition to the .beta.-hydroxyalkylamide endgroups. This
polyesteramide results in improved mechanical coating properties by
more extensive hydrogen bridge formation, improved crosslinkdensity
and improved hydrolysis resistance.
[0171] The invention will be elucidated with reference to the
following, non-limiting examples.
EXAMPLE I
[0172] Preparation of a Highly Branched Polymer Comprising Units of
Phthalic Anhydride and Diisopropanolamine
[0173] 384 g of phthalic anhydride and 415 g of diisopropanolamine
were introduced into a double-walled glass reactor, which could be
heated by means of thermal oil, fitted with a mechanical stirrer, a
distillation head and nitrogen and vacuum connections. The reaction
mixture was gradually heated, with stirring, to approx. 70.degree.
C. and then more slowly to 170.degree. C. A vacuum was created
during the heating. The pressure in the reactor was adjusted to the
release of reaction water, so that this could be removed from the
reactor through distillation. After a total reaction time of 6
hours the viscous polymer contained less than 0.1 meq/g carboxylic
acid (titrimetrically determined) and no more water could be
removed through distillation. After cooling the polymer was
obtained as a very pale yellow glassy mass. The concentration of
hydroxyl groups was titrimetrically found to be 5.4 meq/g. The
number average molecular mass was determined with the aid of GPC
(universal calibration) and was 1500 g/mol; the weight average
molecular mass was 7700 g/mol.
EXAMPLE II
[0174] Preparation of a Highly Branched Polymer Comprising Units of
Phthalic Anhydride and Diisopropanolamine
[0175] 232 g of phthalic anhydride and 270 g of diisopropanolamine
were introduced into a double-walled glass reactor, which could be
heated by means of thermal oil, fitted with a mechanical stirrer, a
distillation head and nitrogen and vacuum connections. The reaction
mixture was gradually heated, with stirring, to approx. 70.degree.
C. and then more slowly to 170.degree. C. A vacuum was created
during the heating. The pressure in the reactor was adjusted to the
release of reaction water, so that this could be removed from the
reactor through distillation. After a total reaction time of 5
hours the viscous polymer contained less than 0.2 meq/g of
carboxylic acid (titrimetrically determined) and no more water
could be removed through distillation. After cooling the polymer
was obtained as a pale yellow glassy mass. The concentration of
hydroxyl groups was titrimetrically found to be 5.8 meq/g. The
number average molecular mass was determined with the aid of GPC
(universal calibration) and was 1100 g/mol; the weight average
molecular mass 4900 g/mol.
EXAMPLE III
[0176] Preparation of a Highly Branched Polymer Comprising Units of
Hexahydrophthalic Anhydride and Diisopropanolamine
[0177] 398 g of hexahydrophthalic anhydride and 408 g of
diisopropanolamine were introduced into a double-walled glass
reactor, which could be heated by means of thermal oil, fitted with
a mechanical stirrer, a distillation head and nitrogen and vacuum
connections. The reaction mixture was gradually heated, with
stirring, to approx. 70.degree. C. and then more slowly to
160.degree. C. A vacuum was created during the heating. The
pressure in the reactor was adjusted to the release of reaction
water, so that this could be removed from the reactor by means of
distillation. After a total reaction time of 3.5 hours the viscous
polymer contained less than 0.2 meq/g of carboxylic acid
(titrimetrically determined) and no more water could be removed
through distillation. After cooling the polymer was obtained as an
almost colourless glassy mass. The concentration of hydroxyl groups
was titrimetrically found to be 5.2 meq/g. The number average
molecular mass was determined with the aid of GPC (universal
calibration) and was 1550 g/mol; the weight average molecular was
mass 7000 g/mol.
EXAMPLE IV
[0178] Preparation of a Highly Branched Polymer Comprising Units of
Hexahydrophthalic Anhydride and Diisopropanolamine
[0179] 378 g of hexahydrophthalic anhydride and 436 g of
diisopropanolamine were introduced into a double-walled glass
reactor, which could be heated by means of thermal oil, fitted with
a mechanical stirrer, a distillation head and nitrogen and vacuum
connections. The reaction mixture was gradually heated, with
stirring, to approx. 70.degree. C. and then more slowly to
160.degree. C. A vacuum was created during the heating. The
pressure in the reactor was adjusted to the release of reaction
water, so that this could be removed from the reactor through
distillation. After a total reaction time of 5 hours the viscous
polymer contained less than 0.1 meq/g carboxylic acid
(titrimetrically determined) and no more water could be removed
through distillation. After cooling the polymer was obtained as an
almost colourless glassy mass. The concentration of hydroxyl groups
was titrimetrically found to be 6.1 meq/g. The number average
molecular mass was determined with the aid of GPC (universal
calibration) and was 1010 g/mol; the weight average molecular mass
4600 g/mol.
EXAMPLES V-VIII
[0180] Powder-paint Compositions Comprising a Polymer According to
any One of Examples I-IV
[0181] Powder-paint compositions according to Table 1 were prepared
by mixing and extrusion (PRISM extruder, 120.degree. C.). The
polyesters (Uralac 5040.TM. and Uralac 5261.TM. from DSM Resins)
comprise units of terephthalic acid, adipic acid, neopentyl glycol
and trimellitic anhydride.
[0182] The compositions were in the usual manner ground, sieved and
electrostatically sprayed (Corona) onto aluminium and steel test
panels. After a cure cycle of 10 minutes at 200.degree. C. or 15
minutes at 180.degree. C. in a circulation oven, the panels were
tested to determine their appearance (visually), flexibility
(penetration in mm according to Erichsen ISO 1520/DIN 53156),
reverse impact resistance (ASTM-2794/69 in inch-pound), acetone
resistance (acetone double rubs), adhesion (cross hatch adhesion
test) and hardness (Konig, seconds). The test results are shown in
Table 1.
[0183] These examples show that the polymers according to the
invention result in coatings having good to very good chemical,
mechanical and optical properties and a high blister limit
(visually).
1TABLE 1 Compositions and coating properties Composition A B C D E
F Polyester resin: Uralac p5261 .TM. 155 g 159 g 164 g Uralac p5040
.TM. 156 g 162 g 160 g Crosslinker according to: Example I 45 g 44
g Example II 38 g Example III 43 g 42 g Example IV 36 g Additives:
TiO.sub.2 2160 100 g 100 g 100 g 100 g 100 g 100 g Benzoin 3.0 g
3.0 g 3.0 g 3.0 g 3.0 g 3.0 g BYK 361 1.5 g 1.5 g 1.5 g 1.5 g 1.5 g
1.5 g cure cycle 10' 200.degree. C. 10' 200.degree. C. 10'
200.degree. C. 15' 180.degree. C. 15' 180.degree. C. 15'
180.degree. C. Hardness 235 s 225 s 215 s 215 s 210 s 195 s Impact
resistance.sup.1) >160 ip 160 ip >160 ip >160 ip >160
ip >160 ip ESP.sup.2) >8 mm >8 mm >8 mm >8 mm >8
mm >8 mm Adhesion.sup.3) Gt0 Gt0 Gt0 Gt0 Gt0 Gt0 Gel time.sup.4)
n.d..sup.5) 151 80 116 85 100 Flow behaviour OK OK OK OK OK OK
Blister limit 120 .mu. 120 .mu. 130 .mu. 140 .mu. 140 .mu. 140
.mu.
[0184] 1) reverse impact test; on steel ASTM-2794/69. The impact
resistance is usually given as inch x pound. If no cracks are
visible in the coating at 160 i.p., 160 i.p. is quoted as the
result. An impact resistance of 160 i.p. stands for 1.84 m.kg.
[0185] 2) Erichsen Slow Penetration; ISO 1520/DIN 53156
[0186] 3) Cross-hatch adhesion; ISO 2409/DIN 5315
[0187] 4) DIN 55990; part B.
[0188] 5) not determined.
* * * * *