Patent GB-617404-A (GB)
Title: Improvements in or relating to cutting lubricants
IPC: C10M173/00
Filed: 1946-09-30
Abstract: A water emulsifiable cutting compound comprises 1-15 parts by weight of an ester of partially dehydrated sorbitol (the esterifying radical of which contains 8-30 carbon atoms), 1-15 parts by weight of the reaction product of such an ester with an aliphatic epoxide, and 0.1-15 parts by weight of an organic ester of an acid of phosphorus, e.g. tricresyl phosphate.  [An aliphatic epoxide (also called an "olefine epoxide" or "inner ether") may be regarded as being derived from an aliphatic hydrocarbon by the attachment of an oxygen atom to two carbon atoms of a carbon chain in such a manner that a mono-oxy carbon-oxygen ring is formed.  The carbon atoms joined to the oxygen atom may or may not be joined to one another and aliphatic epoxides may be represented by the general structural formula <FORM:0617404/III/1> where R and R1 may be hydrogen atoms or monovalent hydrocarbon radicals and N may be zero or a whole number.] The composition may comprise two parts by weight of oleic acid-sorbitol ester, two parts by weight of the reaction product obtained from a palmitic acid-sorbitol ester and ethylene oxide, and two parts by weight of tricresyl phosphate.  The cutting composition may be mixed with mineral lubricating oil, the latter constituting for example 60-80 per cent by weight of the mixture which may then be diluted with water.  The cutting oil may be prepared by mixing and stirring the ingredients including mineral oil to a temperature sufficient to bring them into a homogeneous solution, e.g. up to 150 DEG  F., and a minute amount of water may be added to facilitate the process.  The solution may be stirred into water to form an emulsion. The acid of phosphorus contained in these cutting oils and cutting compounds may be phosphoric acid, phosphorous acid, thiophosphoric acid or thiophosphorous acid, or mixtures of these.  The corresponding esters may be formed by the substitution of all or part of the hydrogen of the phosphorus acid by an aliphatic or an aromatic hydrocarbon radical.  The 8-30 carbon atom acids used for the esterification of the partially dehydrated sorbitol may be those which are present combined with glycerin in naturally occurring animal and vegetable oils and fats, synthetically prepared aliphatic monocarboxylic higher fatty acids, fatty acids prepared by oxidizing hydrocarbons, hydrogenated fatty acids or naphthenic acids, or mixtures of two or more of these classes of acid.  The esters are made by reacting 1 mol. of sorbitol or partially dehydrated sorbitol with one to three mols. of the acid either with or without a catalyst such as sulphuric or phosphoric acids or sodium hydroxide (see Group IV (b)).  The ester-epoxide reaction products are prepared by reacting one mol. of the ester with one to two mols. of the epoxide in the presence of a catalyst (see Group IV (b)).  In making up cutting emulsions 0.1 to 15 per cent by weight of the phosphorus compound (based on the total composition) is intimately mixed with 2-10 per cent by weight of emulsifier, heating if necessary, and the mixture incorporated with stirring in water. If the ester portion of the emulsifier is solid at room temperature, the homogeneous concentrate heated to 140 DEG  F. to 150 DEG  F. may be incorporated in a small amount of water heated to above the m. pt. of the ester and the remainder of the water then added hot or cold.  0.05 per cent to 0.1 per cent of montan or candelilla wax or 0.005 per cent to 0.01 per cent of a polymerized silicone may be added as a foam inhibitor. The mineral lubricating oil, when present, may have a viscosity within the range 90-500 S.U.S. at 100 DEG  F., an A.P.I. gravity of 23-33 DEG  F. and a flash-point above 300 DEG  F., the preferred oil being a light Coastal oil having an A.P.I. gravity of 25-31 DEG  F. and a viscosity at 100 DEG  F. of 100-300 seconds.  The cutting lubricants containing mineral oil may be diluted with water in the proportion of one part of concentrate to nine parts of water, and the ratio of ester-epoxide reaction product to ester should be about three parts or more of the former to one of the latter.ALSO:Esters of partially dehydrated sorbitol are prepared by reacting 1 mol. of sorbitol, or partially dehydrated sorbitol, with 1-3 mols. of a monocarboxylic acid containing 8-30 carbon atoms, such as palmitic or oleic acid, with or without a catalyst such as sulphuric or phosphoric acid or sodium hydroxide.  The ingredients are mixed together at 150-300 DEG  C., preferably in a closed mixing kettle in the presence of a current of inert gas or a refluxing hydrocarbon solvent.  In the latter case the water formed by the reaction is trapped out.  The esters may be converted into ether esters by reacting them with aliphatic epoxides such as ethylene oxide, by slowly adding one or two mols. of the epoxide to a mixture of the ester with 1-5 per cent by weight of a catalyst such as stannic chloride.  After about one hour, the reaction is complete and the catalyst may be removed by water washing or by means of an adsorbent such as fuller's earth. The esters and ether ester are used in cutting lubricants (see Group III).