To provide a surface treatment agent capable of imparting excellent water/oil repellency, fingerprint stain removability, abrasion resistance and lubricity to the surface of a substrate. A surface treatment agent for a substrate, comprising a perfluoropolyether group-containing phosphate compound, a coating agent comprising the surface treatment agent and a liquid medium, and a substrate having a surface layer formed from the surface treatment agent or the coating agent.

A composition having a compound having the structure: ##STR00001##
wherein each R is an independently selected alkylphenol-free moiety that is a C.sub.1-20 alkyl, C.sub.2-22 alkenyl, C.sub.6-40 cycloalkyl, C.sub.7-40 cycloalkylene, C.sub.3-20 methoxy alkyl glycol ether, C.sub.3-20 alkyl glycol ether, or YOH moiety; wherein each Y is an independently selected alkylphenol-free moiety that is a C.sub.2-40 alkylene, C.sub.7-40 cycloalkylene, or C.sub.3-40 alkyl lactone moiety; wherein m is an integer ranging from 1 to 100; and wherein x is an integer ranging from 1 to 1000.

A lubricant adheres to a magnetic recording medium via at least one of chemisorption or bonding, and contains a perfluorinated polyether attached to or terminated with a functional group that is phosphonic acid, silanol or carboxylic acid, and may be:

R.sub.1R.sub.fR.sub.1 where R.sub.f is CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.n, CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2, CF.sub.2O[CF(CF.sub.3)CF.sub.2O].sub.nCF.sub.2, CF.sub.2O(CF.sub.2CF.sub.2O).sub.m(CF.sub.2O).sub.nCF.sub.2, CF.sub.2O(CF.sub.2CF.sub.2O).sub.nCF.sub.2, n, m is from 1 to 100 and R.sub.1 is the functional group. A lubricant is formed from a multiple ether segments according to formula:

Re.sup.1Rb.sup.1-Ri-Rc-Ri-Rb.sup.2Re.sup.2; where Rc includes perfluoroalkyl ether, Rb.sup.1 and Rb.sup.2 are, independently, a sidechain segment including a perfluoroalkyl ether, optional Ri independently is a divalent linking segment including a functional group including elements from periodic table Group 13-17, and of Re.sup.1 and Re.sup.2 are phosphonic acid, silanol or carboxylic acid. Lubricant synthesis includes reacting a perfluorinated polyether with a halogenated functional group, selected from phosphonic acid, silanol or carboxylic acid.

To provide a surface treatment agent capable of imparting excellent water/oil repellency, fingerprint stain removability, abrasion resistance and lubricity to the surface of a substrate. A surface treatment agent for a substrate, comprising a perfluoropolyether group-containing phosphate compound, a coating agent comprising the surface treatment agent and a liquid medium, and a substrate having a surface layer formed from the surface treatment agent or the coating agent.

To provide a surface treatment agent capable of imparting excellent water/oil repellency, fingerprint stain removability, abrasion resistance and lubricity to the surface of a substrate.

A surface treatment agent for a substrate, comprising a perfluoropolyether group-containing phosphate compound, a coating agent comprising the surface treatment agent and a liquid medium, and a substrate having a surface layer formed from the surface treatment agent or the coating agent.

A composition having a compound having the structure:

##STR00001##

wherein each R is an independently selected alkylphenol-free moiety that is a C.sub.1-20 alkyl, C.sub.2-22 alkenyl, C.sub.6-40 cycloalkyl, C.sub.7-40 cycloalkylene, C.sub.3-20 methoxy alkyl glycol ether, C.sub.3-20 alkyl glycol ether, or YOH moiety; wherein each Y is an independently selected alkylphenol-free moiety that is a C.sub.2-40 alkylene, C.sub.7-40 cycloalkylene, or C.sub.3-40 alkyl lactone moiety; wherein m is an integer ranging from 1 to 100; and wherein x is an integer ranging from 1 to 1000.

A compound of the formula (1), and lubricant, and magnetic disk each using the same
A-OCH.sub.2RfCH.sub.2B(1)
wherein A is a group of the formula (a) below, B is a group of the formula (b) or (c) or (d) below, p is 0, 1 or 2, q is a real number of 2 to 10, R is C.sub.1-4 fluoroalkyl, Ar is unsubstituted or substituted aromatic group with C.sub.1-30 alkyl or C.sub.1-30 alkoxyl, Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.yCF.sub.2CF.sub.2CF.sub.2, x and y are each a real number of 0 to 50. ##STR00001##

To provide a surface treatment agent capable of imparting excellent water/oil repellency, fingerprint stain removability, abrasion resistance and lubricity to the surface of a substrate.

A surface treatment agent for a substrate, comprising a perfluoropolyether group-containing phosphate compound, a coating agent comprising the surface treatment agent and a liquid medium, and a substrate having a surface layer formed from the surface treatment agent or the coating agent.