Patent GB-942672-A (GB)
Title: Drawing lubricant coating methods and compositions
IPC: B21C9/00
Filed: 1960-06-01
Abstract: 942,672. Cupping. S. E. MATTHEWS (H. A. Montgomery Co.). June 1, 1960, No. 19451/60. Heading B3Q. [Also in Divisions B2 and D1] A process for preparing a sheet of metal for subsequent fabrication e.g. deep drawing comprises applying and forcibly pressing into intimate contact with a surface of the sheet a film of a noncongealing, aqueous soap solution which is liquid at the application temperature and which contains at least about 5% by weight of soap, and evaporating water from said film until the moisture content thereof is reduced to less than about 15% by weight while maintaining the temperature of said film and said metal sheet at the completion of the evaporating step below about 150‹ F. preferably below 120‹ F. The coating compositions comprise mixtures of an organic amine soap and an alkali metal soap, the soaps being formed with low titer fatty acids e.g. below 30‹ C. The fatty acids may be oleic acid, ricinoleic acid or tall oil or mixtures derived from castor, coconut, palm kernel, linseed, olive, peanut, rape seed, corn and soya bean oils. The amines may be any of the water soluble organic amines having boiling points above 100‹ C. e.g. ethylene diamine, monoethanolamine, diethanolamine, triethanolamine, dimethyl ethanolamine, monoisopropanolamine, morpholine, 2-amino-1-butanol, 2 - amino - 2 - methyl - 1 - propanol, 2 - amino- 2 - methyl - 1, 3 - propanediol, and 2 - amino- 2 - ethyl - 1, 3 - propanediol. The alkali metal soaps may be any of the sodium and/or potassium derivatives of the low titer acids. Specific examples of the coating composition are given in the Specification. Softer coatings are produced by adding 5% to 15% of a plasticizer e.g. water soluble glycols, polyoxyethylene derivatives and sulphonated or sulphated fatty oils. Methyl cellulose and/or polyvinyl alcohol may be added to form a tack-free film on the coating to prevent the coated sheets from sticking together when stacked. Chlorinated oils, flowers of sulphur or colloidal graphite may be added to the coating to improve its lubricating characteristics. In an embodiment a sheet of steel 11 from a stack 12 is cleaned by passing it through a roller leveller 13 having a pair of offset scrubbing brushes 14 followed by straightening rolls 16. Oil and light particles removed from the sheet accumulate on the surface of the cleaning solution on the reservoir 18 and are drained off through an overflow pipe 19. As the sheet leaves the roller-leveller an air blast from a nozzle 20 removes any excess cleaning solution which collects on a trough 20a. The sheet then passes through a roller coating apparatus 21 comprising rubber rolls 22 and steel doctor rolls 24. The coated sheet then passes through a hot air drying apparatus 25. A scrubbing machine comprising pairs of driving rolls 32, 34 and 35 and offset scrubbing brushes 33, Fig. 2, may be substituted for the rollerleveller 13. Squeezer rolls 39 remove excess cleaning fluid. In another embodiment the coating solution is applied by the brushes 42 of roller-leveller, Fig. 3, and the coating is dried as the sheet leaves the apparatus by fans 46. In a further embodiment, Fig. 4, the sheet 11a is fed from a reel 50 through a straightening device 51, a scrubbing machine 13a, past an air blast nozzle 20 through coating rolls 21 and then back beneath all the apparatus to metal working machines for fabrication or to storage rolls or stacks. U.S.A. Specification 2,774,684 is referred to.