Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-02-17
2001-10-30
Metzmaier, Daniel S. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S115000, C524S136000, C524S513000, C524S522000, C516S034000, C516S077000, C516S033000, C516S081000, C106S503000
Reexamination Certificate
active
06310123
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to phosphoric esters
a) obtainable by reacting an &ohgr;-hydroxy-functional oligo- or poly(alkyl)styrene with an alkylene oxide to give a poly(alkyl)styrene-block(b)-polyalkylene oxide copolymer and then converting said copolymer into the corresponding phosphoric esters with a phosphorus compound which forms phosphoric esters, up to 100% of the terminal hydroxyl groups of said poly (alkyl)styrene-block(b)-polyalkylene oxide copolymer being reacted to give phosphoric ester groups and the phosphorus atoms, depending on the chosen stoichiometric proportions, being mono- and/or diesterified, or
b) based on polystyrene oxide-block(b)-polyalkylene oxide copolymers obtainable starting from a monofunctional starter alcohol by sequential addition of styrene oxide and of an alkylene oxide in accordance with the desired sequence and chain length of the individual segments and subsequently by reaction to give the corresponding phosphoric esters, in the manner described in a).
The invention relates, furthermore, to the preparation of these phosphoric esters and to their use as dispersants for pigments and fillers.
BACKGROUND OF THE INVENTION
For the dispersion of fillers and pigments in liquid media it is common to operate with the aid of dispersants in order to reduce the mechanical shear forces required for effective dispersion of the solids and at the same time to obtain very high degrees of filling.
The dispersants support the disruption of agglomerates, wet and/or cover, as surface-active materials, the surface of the particles to be dispersed, and stabilize the particles against unwanted reagglomeration.
Dispersants have become indispensable for the preparation, for example, of highly concentrated color pastes for the paints and coatings industry, for the preparation of pigment concentrates (masterbatches) for the coloring of articles made of plastic, and for the processing of unsaturated polyester resins (UP resins) which comprise large amounts of calcium carbonate or aluminum hydroxide (ATH) as fillers.
The combination of very high degrees of filling in association with a very low viscosity is of particular interest for the producers and users of these products on primarily economic grounds. In the case of the fillers, these commonly constitute the least expensive formulating component; pigment concentrates are intended by the plastics processor to be used for coloring in very highly concentrated form—that is, as far as possible without additional carrier materials.
Phosphoric esters and their use as dispersants are known and can be found in the prior art. For instance, U.S. Pat. No. 4,720,514 describes phosphoric esters of a range of alkylphenol ethoxylates, which can be used with advantage to formulate aqueous pigment dispersions. Phosphoric esters for similar use are described in EP-A-0,256,427. U.S. Pat. No. 5,130,463 and U.S. Pat. No. 5,151,218 report phosphoric esters based on hydroxy-terminated polyaddition products and polycondensation products, which are used for the preparation of highly filled polyester molding compounds, especially for SMC and BMC formulations (SMC=sheet molding compounds; BMC=bulk molding compounds). Bifunctional phosphoric esters prepared by the Mannich-Moedritzer reaction, and their adsorption characteristics on calcium carbonate, are described in J. Appl. Polym. Sci. 65, 2545 (1997).
The known phosphoric esters, however, have the disadvantage that in general they are not universally applicable since there is in many cases a lack of adequate compatibility between the dispersing additive and binder or between the dispersing additive and the surrounding medium (aqueous or solvent-containing formulations). The chemical composition of the phosphoric esters also has a large part to play: in aqueous formulations it is preferred to use only those phosphoric esters whose molecule carries no additional hydrolyzable functional groups, such as ester or urethane groups. Frequently, high levels of dispersing additives are required in order to suppress the incidence of agglomerates; the degrees of filling which can be achieved are unsatisfactorily low, the stability of the dispersions and thus the permanence of the viscosity is often inadequate, and flocculation and aggregation cannot always be avoided, possibly resulting in visible separation and in flow defects and surface defects.
BRIEF SUMMARY OF THE INVENTION
It is therefore an object of the present invention to overcome a large number of the above disadvantages and in so doing to achieve not only the viscosity reduction of highly filled dispersions that is important for processability but also improved compatibility with the surrounding medium.
This object is surprisingly achieved through the use of phosphoric esters of amphiphilic block copolymers having the characteristic structural feature of a poly(alkyl)styrene segment and/or a polystyrene oxide segment to which a polyalkylene oxide segment is attached.
The invention accordingly provides phosphoric esters of the general formula I
x is 1 or 2,
n is a number from 2 to 18,
m and
o are each a number from 2 to 100,
k is a number from 2 to 4,
R″ is H or a linear or branched alkyl radical which may if desired be substituted by additional functional groups, and
R′ is an alkyl, alkaryl, alkenyl or sulfopropyl radical.
DETAILED DESCRIPTION OF THE INVENTION
Preferably R″=H.
R′ is commonly derived from an alcohol R′OH which functions as the starter alcohol for the polymerization of the styrene oxide and alkylene oxide.
Examples of the radicals R′ are the methyl, butyl, stearyl, allyl, hexenyl, nonylphenyl and oleyl radicals.
Methyl and butyl radicals are preferred for R′.
Where n=2 the polyether radical contains exclusively ethylene oxide units. Where n>2, the polyether radical consists of ethylene oxide units and, proportionally, of oxyalkylene units whose carbon number is between 3 and 18. In this case n can adopt the value of a fractional number between 2 and 18. Preferably, the oxyalkylene block consists of ethylene oxide units, with the additional presence if desired of oxybutylene units in addition to the oxypropylene units. Oxyalkylene units having a carbon number of from 4 to 18 are preferred when, in addition, it is desired for the product to have oleophilic properties.
The average molecular weight of the phosphoric esters of the invention lies within the range from 300 to about 15,000 g/mol, preferably from 500 to 5000 g/mol. It can be determined with great ease by the customary methods of polymer analysis, both for the phosphoric esters and for the amphiphilic block copolymers. The ratio of m to o is from 1:50 to 50:1, preferably from 1:10 to 10:1 and, with particular preference, from 1:2 to 10:1.
Examples of suitable phosphoric esters are:
Starting materials used to prepare the phosphoric esters of the invention are, accordingly, amphiphilic block copolymers of the general structures:
respectively, where the radicals R″ and R′ and the indices m, k, n and o are as defined above.
These block copolymers are prepared by reacting the terminal hydroxyl group with a phosphorus compound which forms phosphoric esters, to give the phosphoric esters of the invention.
Block copolymers of this kind are described, for example, in DE-A-41 34 967. The polystyrene-b-polyalkylene oxide copolymers of type A-B are prepared by first subjecting styrene to free-radical polymerization in the presence of sufficient amounts of an initiator and of an amount, corresponding to the desired chain length, of a chain regulator which carries not only a mercapto group but also another functional group having an active hydrogen radical, generally a hydroxyl group, and subjecting the resulting polymer to an addition reaction at temperatures from 20 to 180° C. with alkylene oxide until the desired molecular weight in the block B is reached.
The corresponding polystyrene oxide-b-polyalkylene oxide copolymers are prepared, starting from the starter alco
Boinowitz Tammo
Esselborn Eberhard
Knebelkamp Arno
Psiorz Christian
Silber Stefan
Goldschmidt AG
Metzmaier Daniel S.
Scully Scott Murphy & Presser
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