CA1208231A - Isocyanate adduct dispersants for pigmented coating compositions - Google Patents

Abstract

TITLE
ISOCYANATE ADDUCT DISPERSANTS
FOR PIGMENTED COATING COMPOSITIONS
ABSTRACT
Dispersants which improve the gloss of acrylic paints are prepared by reacting the isocyanate groups of monomeric polyisocyanates or isocyanate acrylate polymers with (1) fatty amines, (2) lower alkylamines or alkanolamines and (3), optionally, aminosilanes. A
formula for the dispersants may be written as:

isocyanate residue, A is fatty amine residue with a =
20-80, B is lower alkylamine or alkanolamine residue with b = 80-20, and C is aminosilane residue with c = 0-40, the sum of a + b + c = 100, the (mole) percentage of isocyanate groups replaced.

Description

"` ~2~ 3~

TITLE
ISOCYANATE ADDUCT DISPERSANTS
FOR PIGMENTED COATING COMPOSITIONS
BACKGROUND OF THE INVENTION
1. Field of the Invention .. . . _ This invention relates to novel compounds useful as dispersants in coating compositions.

2. Prior Art Plke U.S. Patent 2,662,027 shows aluminum flake in paints and discusses "two-tone" finishes.
Simms U.S. Patent 4,219,632 and Brixius and Simms U.S. Patent 4,222,909 show isocyanato~alkyl acrylate and methacrylate polymers of controlled low molecular weight-Thompson U.S. Patent 3,788,996 showscoating compositions with film-forming polymers containing known dispersants.
BRIEF DESCRIPTION OF THE INVENTION
The novel compounds of this invention are of the type sometimes called "AB" dispersants. Such dispersants have the general formula A-Z-B where Z
is an organic linking radical, usually monomeric, and A and B are substituents having different polarities but attached to the same radical. Thus, A can be hydrophobic radical such as that of a fatty amine. It is then compatible with fat or grease which may be present on aluminum flake or other inorganic pigment. At the same time, B can be a hydrophilic radical containing, for example, a hydroxyl group or even, in this case, a lower alkyl amine and hence compatible with a film-forming polymer used as a dispersing medium. The dispersing agent thus aids in the dispersal of the pigment by helping maintain it in dispersion.

. ~

;~lA2G~231 The formula for the compounds of t~is inven-tion, prepared by the direct interaction of the precursors, may be written as ~A]a ~ I rB]b ~C]c where Z is an organic linking radical resulting from the reaction of a polyisocyanate, generally polymeric, with amines as defined below yielding the moieties A and B
and, optionally,Cin the ratios a, b and c.
DETAILED D~S'CRIPTION OF THE INVENTION
As noted, the organic linking radical Z in AB dispersants of the 'formula given above is generally monomexic, Here,' however, it is generall~ polymeric, res'ultins, in ~act, from the 'reaction of a polymerized ester of an isocyanatoalkyl acryltc or methacrylic acid having at least 10-25~ by weight of Isocyanate monomer and a number average molecular wei'ght Mn of 500-10,000 with an amine as defined hereinafter through a urea linkage of the formula o where Rl and R2 are alkyl radicals.
The polymeric isocyanate esters from which Z
is derived may be any of those of the Brixius et al and Simms references noted above. They may be either homo-polymers, i.e., of the isocyanatoalkyl!esters alone, or copolymers of the esters with one or mqre other ethyleni-cally unsaturated monomers. The Brixius et al polymers contain sulfide end groups. The preferred isocyanate ester is isocyanatoethyl methacrylate tIEM).
Any comonomer polymerized with the isocyanate ester in æ is preferably at least one of the group con-sisting of alkyl acrylates or methacrylates having up to ~2' al~23~

12 atoms in the alkyl group, styrene, ethylene, and vinyl esters such as vinyl acetate and vinyl chloride. More than one of these comonomers may be used together, if desired. Butyl acrylate and styrene are preferred co-monomers and may be employed simultaneously.
While polymeric isocyanate residues are pre-ferred for the purpose o this invention, it is not restricted thereto. Thus, Z can represent any of the monomeric di-, tri-, etc., polyisocyanates shown by the Thompson patent cited. It is understood, of course, that when the optional component C of the formula is employed, the isocyanate is at least a triisocyanate.
A in the formula is here the amine moiety which results from the reaction of the amine group of a fatty acid amine with isocyanate groups initially on the linking radical Z. ~he fatty acid amines are the ali-phatic amines with aliphatic ~roups having between 12 and 24 carbons. The higher amines are preferred, e.y., those having between 16 and 24 carbons in the aliphatic groups.
These fatty acid amines are available commercially under the trade mark Ke~amines sold by the Humko Sheffield Corporation and described in their literature. Primary amines are pre-ferred but secondary amines can be used. Kemamine P-997 D, distilled soya amine, 97% primary, is preferred.
26 B in the formula is the am~ne moiety which results from reaction of the amine group of a lower primary or secondary amine (having up to 6 carbons in the alkyl groups) or of an alkanolamine of up to 6 car-bons in the alkanol groups with isocyanate groups originally on Z. Preferred such compounds are butyl-amines and ethanolamines. Mixtures of various E radicals can be used, if desired, but to no particular purpose.
C in the formula is the optional, but sometimes desirable, amine moiety which results from reaction of the amine'group of a primary or sec'ondary amlnosilane of the 'formula HnN- [ (CH2 ) p-Si (Y~]m whereln Y is alkyl of up to 6 carbons, m and n are 1 or 2 and the sum of m and n is 3,' and p is 6.
All the'isocyanate groups of the linklng radi-cal ~hould be replaced to insure stability of the prod-uct. Consequently, the'subscripts a, b and c should total the value 100, representing the mole percentage of isocyanate replaced. For the purposes o this inven-tion, a can vary between 20 and 80 and b can vary between 80 and 20~ The aminosilane is optional, and c can ~ary between 0 and 40.
It will be appreciatea that, while the moiety Z in the present compounds is associated with specific moieties A, B and C, it need not be so associated. Thus, it can replace the'monomeric polyisocyanates shown by -Thompson as forming the linking radical in dispersants.
In fact, it can replace these monomeric materials gen-erally in dispersants carrying substituents of differing solubility.
The compounds of the formula above can be pre-pared very simply by the direct add~tion o~ the calcu-lated amounts of the reactants. The 'reaction is exo-thermic, however, and reactants should be cooled.
Preferably, therefore, the isocyanate-bearing polymer (or other polyisocyanate) is dissolved in a suitable organic solvent such as methyl ethyl ketone and N-methyl-pyrrolidone and cooled with ice to 5-10C. A mixture of the other reactants is added and the reaction allowed to proceed to completion with stirring, e.g.~ in about an hour. The coreactant amines can be added separately to the isocyanate in calculated amount but nothing is gained by such procedure.

~2 13l3;~31 The compounds of this invention are solids or li~uids~ very soluble in organic solvents and, as noted, they tend to stabilize dispersions of inorganic materials in organic soivents. They are particularly useful as dispersants in dispersions containing metal flake or in-organic pigment. They ma~ also be used with dispersIons of magnetic ox~des such as iron or chromium oxldes in organic liquid for magnetic tapes.
Dispersions using the novel compound may be otherwise conventional coat~ng compositions containing pigments. Such compositions are described, for example, in the Thompson patent clted. Thus, polyvinyl chloride, polyvinyl fluoride, etc., compositions can be used. Pre-ferred, however~ as with Thompson, are acrylic composi-tions containin~ polymers and copolymers of acrylic andmethacrylic acids. The acryl-~c coating compositions of the Khanna and Turner~ U, 5, Patent 4,276,216 based on acrylate polymers bearing hy~r~xyl groups and cured with alkylated melamine formaldehyde cross~linking 20 agents are also usable with the present novel dispersants.
The pigment employed can be any of the inorganic materials commonly used as pigments (including carbon~.
Preferrs~d is aluminum flake, admixed with hydrocarbon and ~nitially in the form of a paste. The hydrocarbon on the surface of the flake provides a coating compatible with the hydrophobic radical A of the dispersants.
The amount of dispersant used in the coating composition depends upon the amount of inorganic pigment present. About 5% by weigh~ based on the weight of the pigment is employed although 1-10% can be used (see Ex-ample 3, below). Generally the dispersant is mixed with the pigment b~fore the latter is dispersed but it can be added separately, if desixed.

When employed in paints or enameIs, dispersants improve the gloss of coatings as described by the term "two-tone" or its synonym "metalllc glamour". Metallic glamour can be objectiveIy measurea with a special goniophotometer using the following geometrical arrange-ment. A coated test panel is positioned hbrizontally within the goniophotometer ~ith the coated sIde facing up. The light from a circular, concentr~ted light source is collimated by a lens and is directed to strike the panel at a small angle, typically 22.5, from the normal.
The light beam reflected from the surface o~ the panel is directed by a second lens, at unity magnification, through a circular aperture having approximately the same diameter as ~he light source. A photocell is positioned at a distance of about 6-10 aperture diame~ers behind the aperture and is of sufficient size to intercept all light reflected from the paneI through the aperture. The panel can be rotated to different viewing angles about an axis that is defined as the intersection of the plane of the panel and the plane defined by the beam of light inci-dent to and reflected from the panel in its original horizontal position. It has been found particularly use-ful to measure the intensity of the reflected light at two different paneI positions, when the panel has been rotated to positions of ~10 and +60 from its initial horizontal position.
The goniophotometer gives unitless numerical readings known as luminous reflectance (G) for each angle from which the panel is viewed. The photocell is cali-brated, with respect to the light source, to indicate aluminous reflectance of 100 for a nonmetallic, matte-surfaced, perfect white viewed at any angle setting.
Nonmetallic coatings give equivalent reflectance readings from any angle of view.

V82~.

In a coating having good metallic glamour, the reflectance measured at 10 will be greater than that measured at 60. The reflectance at a given angle A is related to another visual characterlstic known as light-ness (L) through the equation L(A ~ = 25.29G(A) - 18.83 Goniophotometry, reflectance, and lightness are generally expla~ned in The ~easurement of Appearance, Hunter, R.S~, John Wiley and Sons, New York (1975).
An objective characterization of the metallic glamour, the flake orientation index (F.O.I.~, is in turn expressed as a function of the lightness of the coating at 10 or 60. The mathematical expression is:
F.O.I. = 10 aL/~L(lOD) + L(60~

where ~L - L(10) - L(60). The denominator of this -expression is a normalizing term empirically determined to produce equal F.O.I. values for all coatings having the same metallic glamour, regardless of the color of the coating. It accounts for the color intensity of the coat- -ing and the ability of the coating to hide the substrate, both dependent on the amount of chromatic pigment. An index (I or F.O.I.) of at least 40, preferably ~5, is desirable.
EXAMPLES
There follow some Examples illustrating this invention together with a preliminary Comparative Example.
These differ primarily in that the latter does not employ the dispersant of the invention. In all Examples, ratios, proportions, parts and percentages are in terms of weight and temperatures are in degrees centigrade unless other-wise noted. The dispersants of the invention were tested in acrylate coating compositions of the type shown in the above-~entioned patent of Khanna and Turner.

The ~ollowing polymers,, which form no part of the in~ention, were employed in the examples:
Polymer I. This was the' polymer methyl methacrylate/
butyl acrylate/2-hydroxyethyl acrylate 1n the proportions 30~38~32~ Mn = ca. 3~000; Solids = 83~ in methyl ethyl ketone (MEK~. It may be prepared, ~or exampie, as shown in Example 3 o~ Khanna and Turner.
Polymer II. ThIs was an isocyanate-containing poly-mer of the composition methyl methacrylate~butyl acry-late/IEM/lauryl mercaptan residue/azobis(isobutyronitrile~residue in the proportions 56.7/9.6~28.4/2.1~1.6, prepared, e.g., as in Example 1 of the above-identified Brixius and Simms patent: -~CO = 7.5% on solids; Mn =
ca. 2,200.
Polymer IXI. This was an isocyanate-containing poly-mer of the composition IEM~styrene/butyl acrylate/lauryl mercaptan residue/azobis(isobutyronitrile) residue in the proportions 53.27/19.1/19.6/7.14/1.01, prepared, e.g., according to the procedure of Example 2 of Brixius and Simms: - NCO = 9.94%; Mn = 2,700.
Polymer IV. This was Polymer I from which sub-stantially all MEK had been distilled off.
Polymer V. This was similar to Polymer II except that the proportions methyl methacrylate/butyl acrylate/
IEM/mercaptan/azo were 24.6/24.2/39.7~10.2/1.3: ~NCO =
7.48 %, Mn ='ca. 12,200.
Polymer VI. This was sim;lar to Polymer I with the constituents styrene/methyl ~crylate/butyl acrylate/hy-droxyethyl acrylate~acrylic acid in the proportions 15/
14.8/38/32/0.2: Mw = 3,000 and Mn = 1,500 (see Example 5 of Khanna and Turner).
Comparati~e Example A. An acrylic enamel solution was prepared as follows:

~` ~2~3Z3~

Acrylic Polymer I ~281.86 g) was ~ixed thor-oughly for 20 minutes with a partially methylated/
butylated melamine (Resimine~ X-755; Monsanto; 118.8 g) '~ ,, in butyl Cellosolve~ t23.2g g~. To this mixture was added aluminum flake pigment dispersion (60.37 g), Monastral~ Blue Pigment dispersion (44.4 g; Monastral~
is a trademark'of E. I. du Pont de Nemours and Company), and a fumed silica dIspersant (66.75 g). The mixture was stirred for 20 aditional minutes and an acid cata-lyst, p-toluenesulfonic acid (4'.4 g~, mixed therein over 5 minutes. The final mixture (162 gl was dissolved in MEK
(28'83 g) to form a solution ha~ing a Zahn No. 2 viscosIty of 35 seconds.
B, Solution from A was air sprayed onto tw~
Bonderite~ 40 steeI panels ~Parker Rust-Pr~of Co.) on (1) one in two passes to ~uild up a final ('after b~king) thickness of 1.45 mlls and (2) on the other in three passes to build a f;nal thickness of 2.37 mils. The panels were held for 10 minutes at room temperature (21) and for 10 more at 78 and were cured by kaking at 122.
Both panels exhibited a good appeaxance. When tested goniophotometrically, distinctness o~ image (DO~) for both panels was 40 (on a scale ~rom 0 to 100, 100 being excellent), and 20 gloss was 62.5 and 61.5, respec-tively. For the second panel,~ L = 25.13 and FOI =
37.36.

A. Preparation of Dispersant. To a 250-mil, 4-necked flask fitted with thermometer, ice bath, stir-rer, N2-bubbler, condenser, and addition funnel were charged 100 g of solution of Polymer II (63~ by weight of solids in toluene) and 2 g of N-methyl-2-pyrrolidone additional solvent. This mixture was cooled for a 15-minute period and to it was added, through the addition funnel, a 1/1 molar solution in MEX
(15.0 g) of ethanolamine (3.43 g) and Kemamine~ P-997D

i2¢1 l3Z31 (15.4 g). The -CNO/-NH2 molar ratio (in the combined amines) was also 1/1. After addition was complete (15 -20 minutes), the ice bath was removed and the reaction mixture was allowed to rise to room temperature and was stirred for one hour. Tests showed that all -NCO had re-acted. Toluene (27.5 g) was added to make up a 60.81 solids solution of the dispersant.
B. Pre~aration of Aluminum Elake Dispersion .. . . . . . _ _ Aluminum flake (100 g ; Silberline*3141 AR ; 70~
aluminum particles in mineral spirits) was mixed with MEK (200 ml) for about an hour and filtered to a cake (Solids = 64.33%). To methyl Cellosolve~ (15 g) was added 23.32 y o~ the aluminum cake and 0.2 g of dispersant from A. This mixture was stirred 2-3 hours.
Polymer I (72.79 g) was added and stirring was continued for 2-1/2 hours. Properties of the resulting aluminum/
acrylic dispersion were: ~olids = 71.46%; Al = 14.3%;
Ratio Dispersant/Al = 0.8/100.
C. Preparation of Paint. Polymer I (80.13 g) and Resimine~ X-755 (33.75) were agitated together until thoroughly mixed (20 minutes) and aluminum/acrylic dispersion ~rom B (14.83 g) and Monastral~ Blue Pigment dispersion (44.43 g) were added thereto and mixed for 30 minutes. Butyl Cellosolve~ (11.74 g) and MEK (19 g) were added and mixi~g continued for 15 minutes. Acid catalyst (1.25 g; 20% p-toluenesulfonic acid) was added and hand-mixed and the mixture reduced to a Zahn No. 2 viscosity of 35 seconds as before with MEK (3 g). The physical properties of 30 the paint were substantially the same as those o~ the Comparative Example.
D. Testing of Paint. As in part B of the Com-parative Example, paint from C was sprayed on Bonder-ized~ 40 steel panels. The resultant coatings were held 35 10 minutes at 21, 10 at 78 and 30 at 122. Results are shown in Table I:
*denotes trade mark ~ 32 3 ~

~ABLE I
Bu~ld Run (mils~ 20 Gloss DOI
1 1.55 62.5 50 2 2.4S 60.~ 50

3 1.65 60.5 50

4 2~45 61.3 50 1.55 64.5 50 6 2.A5 63.5 50 For Ru~s 1 and 2, ~L = 29.81 and FOI - 43,47.
For Runs 5 and 6, ~L = 3I.01 and I = 45Ø
In comparison with'the Comparative Example, DOI and FOI are improvea by including the dispersant of this inventlon.

A. Pre'~aration of_Dlspers nt. A solution of Polymer II~ (75 g; 71% by wet'ght of solids in 50~50 ethylene glycol monoethyl ether acetate (Cellosolve~
acetate)/ethyl acetate)and N-methyl-2-pyrrolidone (5 g) were added to a 250-ml flask equipped as before. The solution was cooled in an ice bath and to it was added over 20 minutes a 35/65 molar mixture of ethanolamine (3.85 g) and Kemamine~ P-997D (32.06 g) in MEK (25 g), the temperature rising from 8 to 24.
The temperature was raised to 40 and held for one hour.
~he product showed: -NCO = 0~; Solids = 64%; Cellosolve~
acetate - 7.88~; Ethyl acetate = 7.88~; N-methyl-2-pyrrolidone = 3.62%; MEK = 16.02%.
B. Prepa'ration of'Aluminum Flake Dis~ersion.
A millbase was made u~ from the following:
Ingredi'ent Weight 3Q Washed aluminum flake* 19.93 Dispersant from A 1.16 Toluene 15.66 *Silberline as above. Washed aluminum flake is aluminum flake plus excess toluene mixed and filtered.
These three ingredients were mixed for two hours and ~Z08Z31 :L2 mixed further with Polymer I (71.39 g) for 2-3 hours.
The millbase showed: Solids = 72.2%; Al = 14.44%.
C. Prepar ion of Paint. A paint was made up from the following:
Ingredient Weight Polymer I 256.40 Resimine~ X-755108.00 Butyl Cellosol~e~ 28.00 Monastral~ Blue'Dispersion 40.36 Mill~ase from B 47.08 Fumed Silica Dispersion 59.76 p-Toluene Sulfonic Acid 4.00 MEK 65.00 The'first three ingredients were mixed for 20 minutes and the last five'added with stirring, continued for 30 minutes~ The product was diluted with methyl ethyl ketone: Viscosity a 35 Sec. Zahn No. 2 A

D. Tes'ting of Pa t. When the paint of C was sprayed on Bonderized~ steeI panels as in Example 1, results were as follows:
TABLE II
.. ~, . ... .. .. .
Bu~ld (mils~ 2'0' Gl'oss ' DOI
1.1 62.3 55 2~1 64.8 55 Appearance was good.
EX~MPLE 3 Example 2 was substantially repeated except that the level of dispersant used in the millbase prepa-ration of Example 2 B, i.e., Dispersant/Al weight ratio = 5/100, was raised to A. 20~50 and B. 50/50. The 20 gloss with the composition having the 5/100 ratio was better than with either of the others and was better with the 20/50 ratio than with the 50/50 ratio.

~Z~ 3Z31 A. Preparation of Dispers~ant. Polymer II
(25 g) dissolved in N-methyl-2-pyrrolidone (,2 g) and ~!EK ~6 g) was cooled in ice and to it was added, over a 15-20 minute period, a stoichiometric mixture (-NCO/-NH2 = 1/1) of ethanolamine (0.92 g; 0.25 mol), Kemamine~ P-997D (I0.'69 g; 0.65 mol) and the 2 (C~2)3-si(c2H5)3 (1-33 g; 0.1 mol This compound is sold by Union Carblde as A-llO0*) After the addition of the amines, the reaction mixture was heated to 40-45 and held at that temperature for an hour.
Upon cooling, the solution showed: Solids = 41.06%.
... .. . .. . .. . . .. . .. ..
B. Pre~aration of Aluminum Flake Dispersion. Aluminum paste (21.43 g) and dispel-sant from A (Solution = 1.83 g; Dispersant/Al ratio =

5/100) was mixed in methyl Celiosolve~ (12.0 g) for 2-3 hours. The resultant solution showed: Solids = --71.42%; Aluminum = 14.28~.
C. P~para'tion of' Paint. Three acrylic enamels were made up as follows:
Weights (g) ~5~ 1 2 3 Pol~mer I 70.51 Polymer IV --- 64.7~ 64.72 Resimine~ X-755 29.70 29.70 29.70 Butyl Cellosolve~ 5.87 5.87 5.87 Monastral~ Blue Dispersion 10.96 10.96 10.96 Al flake from B 13.09 13.09 ---Al flake from Ex. 2B ------ 12.g5 Fumed Silica Dispersant18.58 18.58 18.58 p-Toluenesulfonic Acid1.101.10 1.10 Butanol - -15.51 15.51 Isopropanol ---5.79 5.79 MæK 10.0 -~

*denotes trade mark, ~Z~1~23~

The first four ingredients named were mixed for thirty minutes. The next five were added to the mixture with stirring, continued for thirty minutes, and the last three added and mixed for five minutes. Paints were diluted with: (1) 11 g of ~EK (Vis. = 35 Sec.
No. 2 Zahn); (2) 18 g of isopropanol (Vis. = 36);
and (3) 18 g of isopropanol (Vis. = 54.5). In all cases, P/B (Pigment/Binder) = 4.7/100, Al/Binder =
1.7/100, and Blue Pigment /Binder = 2/100.
D. Testlng_of Paint. Paint was sprayed on Bonderized~ panels as in Example lD. Results are shown in Table III:
TABLE III
Build Paint ~L~ 20 Gloss DOI ~ L FOI
1 1.3573.3 65 1 2~2473~0 65 26.12 46.2 2 1.3171.9 65 --- --2 2.0372.8 50-65 31.02 50.4 3 1.3170.3 55 --- --. ., .... _ A. Pre~aration of Dispersant. A solution of Polymer V (90 g in 10 g of MEK and 5 g of N-methyl-2-pyrrolidone) was added to a 250-ml flask equipped as before. The solution was cooled in ice with nitrogen bubbled through and to it was added Kemamine P-997D (28.51 g); n-butylamtne (4.i gJ in the mole ratio 60~40) and MEK (35 g). After the addition was complete, the solution was heated to 40-45 and held there ~or an hour. Upon cooling: Wt. Solids =
50.80%; -NC~ = O.
B. Preparation of Aluminum Flake Dispersion.
. .~
Aluminum flake (25 g), Polymer V (1.47 g) and Polymer VI
(73.06 g) were mixed in methyl Cellosolve~ (35.50 g) for 2 hours. The resultant solution showed: Solids =
57.13%; Al = 11.43~).

~.208231 C. Pre~aration and Testing of Paint. An acrylic enamel was made'up as follows:
In~redient We~ght Polymer VI ;71.i8 g Resimine~ X-755 300.00 g ~Lue Millbase 164,.6 g Red Millbase 24.2 g Green Millbase 25.1 g Fumed Silica Dispe~sant 168.9 g The first two ingredients and the next four were separately mixed and then mixed together. The re-sultant mixture (87.71 g) was further mixed wlth alumi-num flake from B and p-toluenesul~onic acid ('0.70 g) in xylene ~10,02 g~ and higher boiling aromatic hydrocarbon (19.21 g).
When the pa~nt wa~s spray~d onto a Bond~rized~
steel panel to a thickness of 2.01 mils, the following properties were found: 20 Gloss = 70.3; DOI = 65; MOI
= 50.67;~ L = 35.17.
Having described my ln~entIon . .

Claims (40)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A composition of the formula A, B and C are connected to Z by urea linkages, Z is a polyisocyanate moiety, it being understood that Z is at least a triisocyanate when all of A, B and C are present, A is the residue which results from the removal of amino hydrogen from a primary or secondary fatty acid amine of 12-24 carbon atoms in the fatty acid groups;
B is the residue which results from the removal of amino hydrogen from a primary or secondary alkyl amine or alkanolamine of up to 6 carbon atoms in the alkyl or alkanol groups;
C is the residue which results from the removal of amino hydrogen from a primary or secondary aminosilane of the formula HnN-[(CH2)p-Si-(OY)3]m wherein Y is alkyl of 2-6 carbon atoms, m and n are each 1 or 2 and the sum of m and n is 3, and p is 2-6; and a is 20-80, b is 80-20, and c is 0-40, the sum of a, b and c being 100, the mole percentage of -NCO
groups adducted to Z.

2. A composition of Claim 1 wherein Z is a polyisocyanate moiety which results from the replacement of the -NCO groups on a polymer of a number average molecular weight of 500-10,000 produced by reacting at least 10% by weight of an isocyanatoalkyl acry-late or isocyanatoalkyl methacrylate alone or with at least one other polymerizable monomer selected from the group consisting of alkyl acrylates and methacrylates having 1-12 carbon atoms in the alkyl group;styrene; ethylene; vinyl acetate;
and vinyl chloride.

3. A composition of Claim 2 wherein Z has terminal sulfide groups.

4. A composition of Claim 2 wherein Z is a polyisocyanate moiety of an isocyanatoethyl methacrylate polymer.

5. A composition of Claim 2 wherein Z is a polyisocyanate moiety of an isocyanatoethyl methacrylate/
butyl acrylate polymer.

6. A composition of Claim 2 wherein Z is a polyisocyanate moiety of an isocyanatoethyl methacrylate/
butyl acrylate/methyl methacrylate polymer.

7. A composition of Claim 2 wherein Z is a polyisocyanate moiety of an isocyanatoethyl methacrylate/
butyl acrylate/styrene polymer.

8. A composition of Claim 2 wherein Z is a polyisocyanate moiety of an isocyanatoethyl methacrylate/
styrene polymer.

9. A composition of Claim 2 wherein A is the residue of a soya primary amine.

10. A composition of Claim 2 wherein B is the residue of ethanolamine.

11. A composition of Claim 2 wherein B is the residue of a butyl amine.

12. A composition of Claim 2 wherein C is the residue of NH2(CH2)3Si(OC2H5)3.

13. A composition of Claim 2 wherein Z is a polyisocyanate moiety of a methyl methacrylate/butyl acrylate/isocyanatoethyl methacrylate polymer, A is the residue of soya oil primary amine, and B is the residue of ethanolamine.

14. The composition of Claim 13 wherein the mole ratio A/B is 1/1.

15. A composition of Claim 2 wherein Z is a polyisocyanate moiety of isocyanatoethyl methacrylate/

styrene/butyl acrylate polymer, A is the residue of a soya oil primary amine, and B is the residue of etha-nolamine.

16. The composition of Claim 15 wherein the mole ratio A/B is 65/35.

17. A composition of Claim 2 wherein Z is a polyisocyanate moiety of a isocyanatoethyl methacrylate/
styrene/butyl acrylate polymer, A is the residue of a soya oil primary amine, B is the residue of ethanol-amine and C is the residue of NH2(CH2)3Si(OC2H5)3.

18. A composition of Claim 17 wherein the mole ratio A/B/C is 65/25/10.

19. A composition of Claim 2 wherein Z is a polyisocyanate moiety of isocyanatoethyl methacrylate/
methyl methacrylate/butyl acrylate polymer, A is the residue of a soya oil primary amine and B is the residue of a butyl amine.

20. The composition of Claim 19 wherein the mole ratio A/B is 60/40.

21. A dispersion comprising:
A. an organic liquid carrier;
B. an inorganic pigment dispersed in the carrier; and C. a composition of Claim 1 also dispersed in the carrier and acting as a dispersant for the inorganic pigment.

22. The dispersion of Claim 21 comprising also a binder dissolved in the liquid carrier.

23. A dispersion of Claim 22 wherein the binder is an acrylic polymer.

24. A dispersion of Claim 23 wherein the pigment is aluminum flake.

25. A dispersion comprising:
A. an organic liquid carrier;
B. a binder dispersed in the carrier;

C. aluminum flake dispersed in the carrier; and D. a composition of Claim 13 or Claim 15 also dispersed in the carrier and acting as a dispersant for the aluminum flake.

26. A dispersion comprising:
A. an organic liquid carrier;
B. a binder dispersed in the carrier;
C. aluminum flake dispersed in the carrier; and D. a composition of Claim 17 or Claim 19 also dispersed in the carrier and acting as a dispersant for the aluminum flake.

27. A substrate carrying a cured coating containing an inorganic pigment and a composition of Claim 1.

28. A substrate of Claim 27 wherein the pigment is aluminum flake.

29. A metal substrate carrying a cured coating containing an inorganic pigment and a composition of Claim 1.

30. A steel substrate carrying a cured coating containing an inorganic pigment and a composition of Claim 1.

31. A steel substrate carrying a cured coating containing flake aluminum and the composition of Claim 13 or Claim 15.

32. A steel substrate carrying a cured coating containing flake aluminum and the composition of Claim 17 or Claim 19.

33. The process of preparing a composition of Claim 1 which comprises reacting the polymer of a number average molecular weight of 500-10,000 produced by reacting at least 10% by weight of an isocyanatoalkyl acrylate or isocyanatoalkyl methacrylate alone or with at least one other polymerizable monomer selected from the group consisting of alkyl acrylates having 2-12 carbon atoms in the alkyl group; alkyl methacrylates having 1-12 carbon atoms in the alkyl group; styrene; ethylene; vinyl acetate;
and vinyl chloride;
a primary or secondary saturated fatty acid amine of 6-24 carbon atoms in the fatty acid groups; and a primary or secondary alkyl amine or alkanolamine of up to 6 carbon atoms in the alkyl or alkanol groups.

34. The process of Claim 33 carried out with cooling.

35. The process of Claim 33 wherein the poly-merized ester, the fatty acid amine and the lower alkyl amine or alkanolamine are reacted simultaneously.

36. The process of Claim 33 wherein the poly-merized ester is reacted first with one co-reactant and then with the other.

37. The process of Claim 33 wherein a primary or secondary aminosilane is also reacted.

38. The process of Claim 37 wherein all the reactants are reacted simultaneously.

39. A composition of Claim 1 wherein A is the residue of a soya oil fatty amine and B is the residue of a primary or secondary alkyl amine of up to 6 carbon atoms in any alkyl group.

40. A composition of Claim 39 wherein any alkyl group is butyl.