ALUMINUM FLAKE DISPERSIONS

Abstract: Aluminum flake can be dispersed advantageously in a mixture of ethylene glycol and ethylene glycol monobutyl either for use in solvent-based dispersions of poly(arylene sulfide) and optionally fluorocarbon.

Description: TITLE Aluminum Flake Dispersions BACKGROUND Dispersions of aluminum flake have been r - \ 5 ' made in mixtures of kerosene and ethylene glycol jj ^ monobutyl ether and other petroleum distillates such as "Solvesso 150" from Exxon Chemicals Co. for use with solvent-based dispersions of poly(arylene sulfide) such as pol (phenylene sulfide) (PPS) 10 and known fluorocarbon polymers such as polytetra- fluoroethylene (PTFE) and copolymers of tetra- fluoroethylene and hexafluoropropylene (FEP) . Such solvent-based dispersions are quite suitable for spray application, but they can exhibit less 15 than desirable settling and flow characteristics for application by coil coating techniques. SUMMARY OF THE INVENTION The present invention provides a dispersion of aluminum flake in a mixture of 20 ethylene glycol and ethylene glycol monobutyl ether. Preferably, each of the ethylene glycol and ethylene glycol monobutyl ether are present in amounts of about 40-60% by weight of the two 25 combined; more preferably at levels of about 55% ethylene glycol, 45% ethylene glycol monobutyl ether. The invention also provides for using such dispersions of aluminum flakes in solvent- 30 based dispersions of pol (phenylene sulfide) and optionally particulate fluorocarbon resin, preferably PTFE or FEP. DETAILED DESCRIPTION By changing the solvent mix and sub- 35 stit ting ethylene glycol for kerosene in the OMPI prior art, the stability and flow characteristics of coating compositions of the invention are improved to an extent desirable for coil coating. The advantages of the invention are especially noticeable in the wetting of the aluminum flake and the production of stable dispersions in poly- phenylene sulfide. The invention will now be illustrated by an example. Parts, percentages and proportions herein are by weight except where indicated otherwise. Example Solvent-Based 66.6 PPS/16 FEP/ 12.75 Ti0 2 /3.65 Al Flake Prepare a premix by grinding i a pebble mill for 48 hours or grinding in a Dyno-mill for 5 passes a blend of "Ry on" V-I PPS resin 22.16 from Phillips Petroleum Co. FEP powder from Du Pont 5 .65 "Tipure R 900" TiO, pigment 4 .24 from Du Pont "Triton X-100" from Rohm δ 6 .14 Haas (isooctylphenoxy- polyethoxyethanol) Channel Black (carbon 2 . 00 colorant) Cobalt blue pigment 0.05 Ethylene glycol 32. 62 Ethylene glycol monobutyl 26 . 69 ether 100 .00 ___ OMPI This pre ix is then mixed in the following proportions: Premix 96.44 Aluminum flake 1.78 Blend of 55 parts ethylene 1.78 glycol and 45 parts ethylene glycol monobutyl ether 100.00 The coating composition has satisfactory dispersion stability and has desirable viscosity and flow characteristics for application to coiled substrate of any suitable material such as aluminum by suitable techniques such as doctor blade or rolling coating. The coating can be cured by heating 10 minutes at 400°C. This drives off the liquid carrier and coalesces into a desirable coating. Alternately, the coating can be cured at 37_0°C _for 15 minutes, at 425°C for 5-7 minutes or under equivalent conditions. - UR£ _OMPI IPO .

Claims: CLAIMS 1. A dispersion of aluminum flakes in a mixture of ethylene glycol and ethylene glycol monobutyl ether wherein each of the ethylene glycol and ethylene glycol monobutyl ether are present in amounts of about 40-60% by weight of the two combined. 2. The dispersion of claim 1 wherein the proportions are, by weight, about 55% ethylene glycol and 45% ethylene glycol monobutyl ether. 3. The solvent-based dispersion of pol (phenylene sulfide) containing a dispersion of claim 1. 4. The solvent-based dispersion of claim 3 also containing fluorocarbon resin in particulate form. 5. The solvent-based dispersion of claim 4 wherein the fluorocarbon resin is poly- tetrafluoroethylene. 6. The. solvent-based dispersion of claim 4 wherein the fluorocarbon resin is a copolymer of tetra luoroethylene and hexa- fluoropropylene. O PI

Inventors: HUYBRECHTS JOZEF THERESIA
Applicants: DU PONT
Application year: 1981
Main classification: C08K3
IPC codes: C08K3, C08L27, C08L81, C09D5, C09D17, C09D181