Pyrimidine-based crosslinking agents

Details Pyrimidine-based crosslinking agents Pyrimidine-based crosslinking agents

2001-11-07

2003-10-14

Nolan, Sandra M. (Department: 1772)

Stock material or miscellaneous articles

Hollow or container type article

Polymer or resin containing

C252S183110, C427S428010, C428S458000, C428S460000, C428S461000, C428S463000, C544S317000

Reexamination Certificate

active

06632495

ABSTRACT:

The present invention relates to novel pyrimidine-based crosslinking agents for thermally curable compositions, especially thermally curable coating materials, adhesives, sealing compounds or compounds for producing moldings. Triazine-based crosslinking agents are known. They comprise tris(alkoxy-carbonylamino)triazines of the formula
in which the radical R stands for alkyl, cycloalkyl or aryl radicals.
These tris(alkoxycarbonylamino)triazines, their preparation, and thermally curable compositions in which they are present as crosslinking agents are described in the patents U.S. Pat. No. 4,939,213, U.S. Pat. No. 5,084,541, U.S. Pat. No. 5,288,865 or EP-A-0 624 577. These crosslinking agents offer numerous advantages; however, owing to their highly symmetrical structure, they tend to crystallize from the thermally curable compositions, which is why only a few derivatives, such as the mixed methyl and butyl esters (R=methyl, butyl), for instance, are suitable for use in practice. This, however, restricts the ability to control the crosslinking temperature and/or the rate of the crosslinking reaction via the choice of the radical R, as is done with other blocked isocyanates.
There is therefore a need for crosslinking agents which have the advantages of the known tris(alkoxycarbonylamino)triazines but not their tendency to crystallize.
The invention accordingly provides the novel pyrimidine-based crosslinking agents for thermally curable compositions.
In the text below, the novel pyrimidine-based crosslinking agents are referred to as “crosslinking agents of the invention”.
The invention also provides the novel thermally curable compositions which comprise the crosslinking agents of the invention and are referred to below as “compositions of the invention”.
The invention provides not least the novel products which are produced from the compositions of the invention and are referred to below as “products of the invention”.
The crosslinking agent of the invention comprises at least one derivative of pyrimidine.
Examples of suitable crosslinking agents of the invention are pyrimidines of the general formula I
in which the variables and the index n have the following definition:
n=
0 or 1
R
1
and R
2
=identical or different radicals of the general formula II:
—NH—(CX)—YR
4
  (II),
in which the variables have the following definition:
X=═O, ═S;
Y=═—O—, —S—, —NH—;
R
4
=monovalent substituted or substituted C
1
to C
20
alkyl, C
2
to C
20
alkenyl, C
4
to C
12
cycloalkyl or cycloalkenyl, C
6
to C
12
aryl or C
6
to C
20
arylalkyl, arylalkenyl, arylcycloalkyl, arylcycloalkenyl, alkylaryl, alkenylaryl, cycloalkylaryl, cycloalkenylaryl, alkylcycloalkyl, alkylcycloalkenyl, alkenylcycloalkyl, alkenylcycloalkenyl, cycloalkylalkyl cycloalkenylalkyl, cycloalkylalkenyl or cycloalkenylalkenyl radical;
R
5
=—F, —Cl, —Br, —I, —CN, —NO
2
, substituted or unsubstituted, radical R4, substituted or unsubstituted radical —YR
4
;
R
3
=radical R
1
or R
2
;
a radical of the general formulae III and IV:
in which the variables R
1
, R
2
, and R
5
have the definition stated. The indices m and o and the variable R
6
have the following definition:
R
6
=alkane-, alkene-, cyclolkane- or cyclo-alkenediyl or -triyl radical or divalent or trivalent aromatic, aromatic-aliphatic, aromatic-cycloaliphatic, aromatic-olefinic or aromatic-cycloolefinic radical;
m=0, 1 or 2,
o=0 or 1;
with the proviso that if R3=a radical of the general formula IV, the radical R1 or R2 of the general formula I may also be a hydrogen atom.
The crosslinking agents of the invention are, in particular, mononuclear (general formula I), dinuclear (general formula I in conjunction with general formula III) and trinuclear (general formula I in conjunction with general formula IV) pyrimidines. It is also possible to employ higher polynuclear pyrimidines, although the technical effects achieved thereby do not always justify the increased synthesis effort.
In accordance with the invention, the mononuclear pyrimidines I are trifunctional in respect of thermal curing. This means that they have three radicals of the general formula II. Although, in specific cases, tetrafunctional mononuclear pyrimidines I are suitable, it is then often the case, for steric reasons, that all of the crosslinking groups (radicals of the general formula II) are no longer amenable to the crosslinking reaction, so that frequently the increased synthesis effort is unjustified.
In accordance with the invention, the dinuclear pyrimidines I/III are advantageously trifunctional or tetrafunctional in the sense referred to above, particularly trifunctional. Although, in specific cases, pyrimidines III of higher functionality may be suitable, such as pentafunctional or hexafunctional pyrimidines III, it is then often the case, for steric reasons, that all of the crosslinking groups (radials of the general formula II) are no longer amenable to the crosslinking reaction, so that the increased synthesis effort is in many cases unjustified.
In accordance with the invention, the trinuclear pyrimidines I/IV are advantageously tri-, tetra-, penta or hexafunctional in the sense referred to above, particularly tri- or tetrafunctional. Although, in very specific cases, pyrimidines I/IV of higher functionality may be suitable, such as hepta-, octa- or nonafunctional pyrimidines I/IV, it is then often the case, for steric reasons, that all of the crosslinking groups (radicals of the general formula II) are no longer amenable to the crosslinking reaction, so that the increased synthesis effort is in the great majority of cases unjustified.
In the general formula I, the radicals R
1
and R
2
stand for identical or different radicals of the general formula II. The decision as to whether identical or different radicals R
1
or R
2
are used is guided by whether it is desired to incorporate crosslinking centers, i.e., crosslinking functional groups, of differing reactivity. The skilled worker will therefore decide, on the basis of simple preliminary considerations, which possibility affords the most advantages in the case in hand.
In the general formula II, the variable X stands for an oxygen atom or a sulfur atom. In accordance with the invention, oxygen atoms are of advantage and are therefore used with preference.
The variable Y of the general formula II likewise stands for an oxygen atom or a sulfur atom and, in addition, for an amino group. In accordance with the invention, the oxygen atoms are of advantage here again and are therefore used with preference.
Accordingly, the radicals R
1
and R
2
used with preference in accordance with the invention comprise, very generally, carbamic esters which contain the above-described R
4
s.
Examples of suitable, unsubstituted or substituted C
1
-C
20
alkyl radicals R
4
for use in accordance with the invention are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl undecyl, dodecyl or pentadecyl radicals.
Examples of suitable substituted or unsubstituted C
2
to C
20
alkenyl, C
4
to C
12
cycloalkyl or cycloalkenyl, C
6
to C
12
aryl or C
6
to C
20
arylalkyl, arylalkenyl, arylcycloalkyl, arylcycloalkenyl, alkylaryl, alkenylaryl, cycloalkylaryl, cycloalkenylaryl, alkylcycloalkyl, alkylcycloalkenyl, alkenylcycloalkyl, alkenylcycloalkenyl, cycloalkylalkyl, cycloalkenylalkyl, cycloalkylalkenyl or cycloalkenylalkenyl radicals R
4
are
In accordance with the invention, methyl, ethyl, propyl, butyl radicals R
4
are of advantage since they are eliminated even at comparatively low temperatures, and the elimination products, especially the corresponding alcohols, are highly volatile, so that they can easily escape from the products of the invention.
The above-described radicals R
4
may have substituents. In very general terms, such substituents comprise groups such as are customary and known in the field of organic chemistry. It should be ensured, however that these groups do not interfere with, let alone suppress

Affiliated with

Also associated with

Rating

Pyrimidine-based crosslinking agents does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Pyrimidine-based crosslinking agents, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pyrimidine-based crosslinking agents will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3145158