Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-03-06
2002-09-24
Michl, Paul R. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S399000
Reexamination Certificate
active
06455621
ABSTRACT:
This application is an application under 35 U.S.C. Section 371 of International Application No. PCT/FR98/01142, filed on Jun. 04, 1999.
The present invention relates to a composition comprising magnesium or calcium acetylacetonate and at least one &bgr;-diketone in free form or in the form of a metal chelate.
It likewise relates to the use of &bgr;-diketones in free form and/or in the form of their metal chelates as agents serving to improve the dispersion of magnesium or calcium acetylacetonate in formulations for halogenated polymers.
Calcium acetylacetonate is one of the well-known heat stabilizers for formulations comprising halogenated polymers, and more particularly polyvinyl chloride.
However, although it is clearly established that the halogenated polymer formulations can be effectively stabilized with respect to temperature, it nevertheless remains the case that the utilization of polymers stabilized in this way exhibits a number of difficulties. It has been found, in fact, that the presence of this specific chelate has been the cause of defects in the shaped polymer. More particularly, it has been noted that the articles obtained may exhibit heterogeneities having the appearance of craters, seeds or else pinholes.
Without wishing to be limited by such an explanation, it appeared that the origin of these defects in the shaped article lies in the fact that calcium acetylacetonate is very difficult to disperse homogeneously within the polymeric formulation. In fact, under the conditions in which formulations based on halogenated polymers are shaped, calcium acetylacetonate is present neither in dissolved form nor in melted form.
The same type of difficulty is anticipated with magnesium acetylacetonate.
One of the aims of the present invention is therefore to provide a solution to the problems of the heterogeneities which appear during the shaping of formulations which are based on halogenated polymers and stabilized by means of magnesium or calcium acetylacetonate.
It has been found, entirely unexpectedly, that a composition comprising the combination of magnesium or calcium acetylacetonate with at least one &bgr;-diketone in free form and/or in metal chelate form, the said &bgr;-diketone being selected such that the melting point of the resulting composition is not more than 200° C., makes it possible to overcome the problems described hereinabove. One of the first consequences of this composition is that its melting point is lower than that of calcium or magnesium acetylacetonate alone. It is recalled that the melting point of calcium acetylacetonate is approximately 250° C. and that of magnesium acetylacetonate is approximately 270° C.
There is a certain advantage in this owing to the fact that, during the utilization of the polymeric formulation, at temperatures which are commonly of the order of 200° C., the composition according to the invention, i.e. comprising magnesium or calcium acetylacetonate and the &bgr;-diketone in free or chelated form, is itself in melted form.
Furthermore, despite the fact that there is nothing to suggest so, the use of this particular mixture, prepared at the time of use, in halogenated polymer formulations makes it possible to improve considerably the homogeneity of the dispersion of magnesium or calcium acetylacetonate, such that the defects which appear when the polymer is shaped are eliminated.
Therefore, a first subject of the present invention consists of a composition having a melting point of less than or equal to 200° C. and comprising magnesium or calcium acetylacetonate and at least one free &bgr;-diketone of the following formula (I):
R
1
COCHR
2
COR
3
in which R
1
and R
3
are identical or different and represent a substituted or unsubstituted linear or branched C
1
-C
30
hydrocarbon radical and R
2
represents a hydrogen atom or a linear or branched C
1
-C
4
hydrocarbon radical; and/or at least one &bgr;-diketone in the form of a lanthanum, magnesium, aluminium, zinc or calcium chelate of the formula (II)
in which R
1
, R
2
, and R
3
are as defined above, M
n+
represents one or more of the abovementioned metals, n being 2 or 3, with the exception of the acetylacetonates of calcium and of magnesium.
A further subject of the invention is a process for preparing the said composition, which consists in contacting magnesium or calcium acetylacetonate and the &bgr;-diketone in free form or in chelate form in a mixer which allows the compounds to be homogenized and, if necessary, ground.
A further subject of the present invention consists in the use of the abovementioned composition as a heat stabilizer in halogenated polymer formulations.
Lastly, a final subject of the invention is the use of the said composition in the shaping of a formulation comprising at least one halogenated polymer for the purpose of preventing the appearance of heterogeneities due to the presence of magnesium or calcium acetylacetonate in the said polymer.
Other features and advantages of the present invention would appear more clearly, however, on reading the following description and examples.
As mentioned hereinabove, the composition according to the invention comprises magnesium or calcium acetylacetonate.
The acetylacetonate forming part of the present invention corresponds to the formula [CH
3
COCHCOCH
3
]
2
M.xH
2
O, in which x is between 0 and 2 and M represents calcium or magnesium.
Calcium acetylacetonate is well known and is found in commerce, for example, under the names Rhodiastab X7®, marketed by Rhodia Chimie.
In the text below, reference will be made only to calcium acetylacetonate, in awareness of the fact that the present invention is not limited to this single acetylacetonate but relates additionally to magnesium acetylacetonate or the combination thereof.
In accordance with the present invention, calcium acetylacetonate is combined with at least one &bgr;-diketone, which can be alternatively in free form, in the form of a metal chelate or in the form of a mixture of these two species.
Therefore, when the &bgr;-diketone is in a free form, it corresponds to the formula (I) R
1
COCHR
2
COR
3
, in which R
1
and R
3
, which are identical or different, each represent a substituted or unsubstituted, linear or branched C
1
-C
30
hydrocarbon radical and R
2
is a hydrogen atom or a linear or branched C
1
-C
4
hydrocarbon radical.
When the &bgr;-diketone is in the form of a metal chelate, it can be represented by the formula (II)
in which M
n+
represents at least one of the following metals: calcium, zinc, aluminium, magnesium or lanthanum, n being 2 or 3, R
1
and R
3
, which are identical or different, represents a substituted or unsubstituted linear or branched C
1
-C
30
hydrocarbon radical and R
2
represents a hydrogen atom or a linear or branched C
1
-C
4
hydrocarbon radical, with the exception of the acetylacetonates of calcium and of magnesium.
In one more specific embodiment of the invention, the radicals R
1
and R
3
, which are identical or different, represent a linear or branched C
1
-C
24
alkyl or alkenyl radical; a C
6
-C
30
aryl radical substituted or unsubstituted by at least one alkyl radical and/or one halogen atom and/or one silicon atom; or a C
3
-C
14
cycloaliphatic radical which can, if desired, contain carbon—carbon double bonds.
Preferably, the radicals R
1
and R
3
, which are identical or different, represent a linear or branched C
1
-C
18
alkyl radical; a C
6
-C
10
aryl radical substituted or unsubstituted by at least one alkyl radical and/or one halogen atom; or a C
3
-C
14
cycloaliphatic radical which can, if desired, contain carbon carbon double bonds.
In a different embodiment, the said radicals R
1
and R
3
can be linked to one another such that the &bgr;-diketone compound is in the form of a ring system.
The above-described radicals R
1
and R
3
can be optionally modified (substituted) by the presence in the aliphatic chain of one or more groups of formula —O—, —CO—O—, —CO—.
The radical R
2
can be either a hydrogen atom or a C
1
-C
4
alkyl radical whose aliphatic cha
Gay Michel
Henrio Françoise
Chimie Rhodia
Michl Paul R.
LandOfFree
Composition based on calcium of magnesium acetylacetonate... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Composition based on calcium of magnesium acetylacetonate..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composition based on calcium of magnesium acetylacetonate... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2866657