Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Primarily organic continuous liquid phase
Reexamination Certificate
2000-09-28
2003-07-29
Metzmaier, Daniel S. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Primarily organic continuous liquid phase
C106S031670, C524S309000, C524S311000, C524S539000, C524S599000, C528S287000, C528S293000, C528S354000
Reexamination Certificate
active
06599947
ABSTRACT:
This invention relates to a new class of dispersants, to dispersions containing such dispersants together with a particulate solid and an organic medium, to millbases and the use of such dispersions and millbases in paints and printing inks.
Dispersants containing a poly(oxypentamethylene carbonyl) chain are well known and are generally prepared by polymerisation involving &egr;-caprolactone. They are said to be particularly useful for dispersing particulate solids in an organic liquid media and contain either acid or basic terminating groups. Dispersants containing terminal basic groups are described in EP 208041 and WO94/21368 and include the reaction products of poly(ethyleneimine) with &egr;-caprolactone in the presence of aliphatic or hydroxyaliphatic carboxyl acids as chain terminators during the polymerisation of the &egr;-caprolactone. Dispersants containing terminal acid groups are described in EP 164817 and include phosphate esters of &egr;-caprolactone polymerised in the presence of a fatty alcohol as chain terminator.
It has now been found that superior dispersants can be made by partially replacing the &egr;-caprolactone used in the preparation of such dispersants by glycolic acid. Dispersants derived from block or random copolymerisation of glycolic acid with &egr;-caprolactone and/or &dgr;-valerolactone have been found particularly advantageous.
According to the invention there is provided a dispersant of general Formula 1.
wherein:
R is hydrogen or a polymerisation terminating group;
Z is an acidic or basic group or a moiety containing either an acidic or basic group;
A is C
3-7
-alkylene optionally substituted by alkyl;
Gly is oxymethylenecarbonyl;
n and m are integers; and
n+m is from 2 to 100;
including salts thereof.
The dispersant of formula 1 is hereinafter referred to as “The Dispersant”.
Preferably n+m is not greater than 70, more preferably not greater than 50 and especially not greater than 20.
The poly (oxyalkylene carbonyl) chain (hereinafter POAC chain) represented by &Brketopenst;(O-A-CO&Brketclosest;
n
(Gly)
m
&Brketclosest; may be a random or block copolymer.
The poly(oxyalkylene carbonyl) chain represented by &Parenopenst;O-A-CO&Parenclosest;
n
is preferably derivable from propiolactone, &dgr;-valerolactone, &egr;-caprolactone or alkyl-substituted &egr;-caprolactone, including mixtures thereof. The preferred lactones are &egr;-caprolactone and &dgr;-valerolactone.
The oxymethylenecarbonyl group represented by Gly is preferably derived from glycolic acid.
When Z is a basic group or moiety containing a basic group, it is preferably a polyamine or polyimine.
It is preferred that the ratio of n to m is between 30:1 and 1:6, more preferably between 20:1 and 1:5, even more preferably between 10:1 and 1:5 and especially between 10:1 and 1:1. Preferably, the MW of the polyester chain represented by R&Brketopenst;(O-A-CO)
n
(Gly)
m
&Brketclosest; is from 600 to 3,000. It is also preferred that the MW of the polyester chain is not less than 800 and especially not less than 1,000.
When Z is polyfunctional, there may be more than one group R&Brketopenst;(O-A-CO&Parenclosest;
n
(Gly)
m
&Brketclosest; attached to each Z.
The alkyl group(s) in &egr;-caprolactone may be linear or branched and is preferably C
1-8
-alkyl, more preferably C
1-6
-alkyl and especially C
1-4
-alkyl. Examples of such groups are methyl and t-butyl.
The alkyl substituted &egr;-caprolactones are obtainable by oxidation of alkyl substituted cyclohexanone and consequently many are mixtures of alkyl substituted &egr;-caprolactone. Thus, the oxidation of 2-methyl cyclohexanone often results in a mixture of 7-methyl (95%) and 3-methyl &egr;-caprolactone (5%). However, the oxidation of 4-alkyl cyclohexanone results in only the 5-alkyl &egr;-caprolactone. Other examples of alkyl substituted &egr;-caprolactone are 6-methyl; 4-methyl; 5-methyl; 5-tert butyl; 4,6,6-trimethyl and 4,4,6-trimethyl derivatives. 7-methyl &egr;-caprolactone is preferred.
Copolymerisation of the lactone and glycolic acid precursors of the POAC chain results in a copolymer having a terminal hydroxy and terminal carboxylic acid group. The groups R and Z may, therefore, be attached to the copolymer either via oxygen or the group —COO—. When Z is a basic group or a moiety containing a basic group such as a polyamine or polyimine the group R is preferably hydrogen or a polymerisation terminating group attached via the oxygen atom of the POAC chain. When Z is an acidic group or a moiety containing an acidic group such as carboxylate, sulphate, sulphonate, phosphonate or phosphate, the group R is preferably a polymerisation terminating group attached via the —CO— group of the POAC chain.
Preferred dispersants are derivable from either a POAC acid (i.e. a POAC chain having a terminal carboxylic acid group) which is end-capped by a polymerisation terminal group (hereinafter TPOAC acid) or from a POAC alcohol (i.e. a POAC chain having a terminal hydroxy group) which is end-capped by a polymerisation terminal group (hereinafter TPOAC alcohol).
According to a first aspect of the invention, The Dispersant comprises a polyamine or polyimine carrying at least two POAC chains of Formula 2.
wherein:
V is a POAC chain moiety &Brketopenst;(O-A-CO)
n
(Gly)
m
&Brketclosest;; and
T is hydrogen or a residue of a chain terminator forming a TPOAC acid.
Preferably the polyamine is polyallylamine or polyvinylamine. However, in a preferred first aspect of the invention, The Dispersant comprises a polyimine and especially a poly(C
2-4
-alkyleneimine) (hereinafter “PAI”).
For clarity, the oxygen and carbonyl groups in the POAC chain of Formula 2 have been included to indicate the manner of attachment of the group T and do not represent additional oxygen or carbonyl groups over and above those present in the oxyalkylene carbonyl group
Each POAC chain is preferably linked to the polyamine or polyimine through either a covalent amide link —CO—N< formed between a terminal carbonyl group of the POAC chain and the nitrogen atom of a primary or secondary amino group in the polyamine or polyimine, or through an ionic salt link —COO
−
HN
+
≡ formed between a terminal carboxylate group of the POAC chain and a positively charged nitrogen atom of a substituted ammonium group in the polyamine or polyimine. Because the Dispersant contains at least two POAC chains it may contain a mixture of amide and salt links depending on the severity of the reaction conditions used in its preparation.
The Dispersant of the first aspect of the invention may be conveniently represented by the general Formula 3.
wherein:
X-*-*-X represents polyamine or polyimine;
Y represents a POAC chain linked to the polyamine or polyimine via an amide or salt linkage;
q is from 2 to 2000; and
POAC is as defined hereinbefore.
Preferably q is not less than 4 and especially not less than 10. It is also preferred that q is not greater than 1000 and preferably not greater than 500.
It is also preferred that the weight ratio of the POAC chain represented by Y to the polyamine or polyimine represented by X-*-*-X is between 30:1 and 1:1, more preferably between 25:1 and 4:1 and especially between 20:1 and 5:1.
The polyamine is preferably PAI and is especially a poly(ethyleneimine) which may be linear or branched (hereinafter PEI).
The PAI preferably has a weight-average molecular weight from 500 to 600,000, more preferably from 1,000 to 200,000, even more preferably from 1,000 to 100,000 and especially from 5,000 to 100,000.
The Dispersant of the first aspect of the invention is obtainable by reacting a polyamine or polyimine with a TPOAC acid of Formula 4 or by reacting a polyamine or polyimine with a lactone and glycolic acid in the presence of a polymerisation terminating compound.
wherein:
T, V, n and m are as defined hereinbefore.
The length of the POAC chain may be controlled by the presence of a chain stopper or terminating compound, such as a carboxylic acid, in the preparative process. Where the Dispersant contains POAC chains formed by the polymerisation o
Avecia Limited
Metzmaier Daniel S.
Pillsbury & Winthrop LLP
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