US 20090239773A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2009/0239773 A1 Haramoto (43) Pub. Date: Sep. 24, 2009 (54) LUBRICANT ADDITIVE, LUBRICANT (86). PCT No.: PCT/UP2007/068O12 COMPOSITION AND GREASE COMPOSITION S371 (c)(1), (2), (4) Date: May 27, 2009 (75) Inventor: Yuhiro Haramoto, Yamanashi (30) Foreign Application Priority Data Sep. 15, 2006 (JP) ................................. 2006-251.096 Correspondence Address: O O WESTERMAN, HATTORI, DANIELS & Publication Classification ADRIAN, LLP (51) Int. Cl. 1250 CONNECTICUT AVENUE, NW, SUITE 700 CIOM 33/40 (2006.01) WASHINGTON, DC 20036 (US) C07D 405/02 (2006.01) fu-sh (52) U.S. Cl. ...................................... 508/267: 546/282.4 73) Assignees: Yamanashi University, Kofu-shi, (73) 9. Yamanashi (JP); Af Co., Ltd., (57) ABSTRACT Ashiya-shi, Hyogo (JP); Nippon A lubricant additive comprising a rod-like liquid crystal com Chemical Industrial Co., Ltd., pound possessing a cation group and an anion is disclosed. Tokyo (JP) The rod-like liquid crystal compound is typically a specific type of 4-(1,3-diox-2-yl)pyridinium salt and exhibits an (21) Appl. No.: 12/441,419 effect of reducing the coefficient of friction ifadded in a small amount. A lubricant composition and a grease composition (22) PCT Filed: Sep. 10, 2007 comprising the lubricant additive are also disclosed. METAL SURFACE Patent Application Publication Sep. 24, 2009 US 2009/0239773 A1 FIG 1 METAL SURFACE FIG 2 (EXAMPLE.3 (2)EXAMPLE 4 (3)COMPARATIVE EXAMPLE 1 O. 1 OOS5 s OOS va Y ... Y.Mar an (C85 FRICTION TIME (MIN) US 2009/0239773 A1 Sep. 24, 2009 LUBRICANT ADDITIVE, LUBRICANT form an intermolecular sequence in which the rod-like liquid COMPOSITION AND GREASE crystal compound possessing a cation group and an anion are COMPOSITION vertically oriented and exhibit metallic interface characteris tics differing from a general rod-like liquid crystal compound TECHNICAL FIELD and that (2) for this reason, the rod-like liquid crystal com pound possessing a cation group and an anion can exhibit, in 0001. The present invention relates to a lubricant additive, practice, an effective friction reducing effect even in a very and a lubricant composition and a grease composition con Small amount. These findings have led to the completion of taining the lubricant additive. the present invention. BACKGROUND ART 0006 Specifically, an invention (1) of the present inven tion provides a lubricant additive comprising a rod-like liquid 0002 Use of liquid crystals as an additive for lubricants crystal compound possessing a cation group and an anion. has been studied. For example, Patent Document 1 discloses 0007 An invention (2) provides the lubricant additive a method of simply changing a frictional force between two according to the invention (1) in which the cation group is a solid bodies by phase transfer of a thermotropic liquid crystal pyridinium group or an ammonium group. and the like introduced between the two bodies of relatively 0008. An invention (3) further provides the lubricant addi movable machine components. Patent Document 2 discloses tive according to the invention (1) or (2) in which the rod-like a lubricant composition comprising a base oil, a liquid crys liquid crystal compound is 4-(1,3-diox-2-yl)pyridinium salt tal, and a friction adjusting agent. Patent Document 3 dis type rod-like liquid crystal compound shown by the following closes a lubricant composition containing a liquid crystal formula (6): compound and a fluorinated oil. Patent Document 4 discloses a lubricant composition containing a base oil, an organic molybdenum compound, and a liquid crystal. The Patent (6) Documents 1 to 4 describe that the friction coefficient can be O reduced by adding a liquid crystal compound to a lubricant composition. (Patent Document 1).JP-A-2-503326 (claims) O v. (Patent Document 2) JP-A-6-128582 (claims) (Patent Document 3).JP-A-7-82582 (claims) wherein RandR indicate alkyl groups, alkoxyl groups, or a (Patent Document 4).JP-A-2004-182855 (claims) group having an unsaturated bond shown by the following 0003. In the methods of the Patent Documents 1 to 4, a formula (4), and X represents a halogen atom, practically useful effect of reducing the friction coefficient cannot be obtained unless the amount of the liquid crystal in the lubricant composition is 1% or more, and preferably 10% (4) or more. However, a liquid crystal compound is a very expen R3 sive material, whereas a lubricant composition must gener ally be available at a low cost. The addition of a liquid crystal CH=C-Z- in an amount of 1% or more to a lubricant composition is unprofitable. This is the reason why no lubricant containing a wherein R represents a hydrogen atom or a methyl group, Z liquid crystal compound is used in practice. There has been no indicates —(CH), , —(CH), O—, —CO-O-(CH2) lubricant composition containing an ionized liquid crystal , —CO-O-(CH), O—, —CH CH-O-, or compound. —CO—, wherein m is an integer of 1 to 30. 0004 An object of the present invention is to provide a 0009. An invention (4) provides the lubricant additive lubricant additive which can exhibit an effect of reducing the according to the invention (3), wherein R7 and R in the coefficient of friction when added in a small amount, and a formula (6) are alkyl groups. lubricant composition and a grease composition containing 0010. An invention (5) provides the lubricant additive the lubricant additive. according to the invention (4), wherein R7 in the formula (6) is an alkyl group having 8 to 22 carbon atoms and R is an DISCLOSURE OF THE INVENTION alkyl group having 1 to 4 carbon atoms. 0005. The inventor of the present invention has conducted 0011. An invention (6) provides a lubricant composition extensive studies in order to solve the above problems in comprising the lubricant additive according to any one of the general technologies. As a result, the inventor has found that inventions (1) to (5). (1) since a rod-like liquid crystal compound possessing a 0012. An invention (7) provides the lubricant composition cation group and an anion has a positive (+) portion and a according to the invention (6), wherein the content of the negative (-) portion of ions at the terminals, these positive and lubricant additive is 0.0001 to 0.1 mass %. negative portions are specifically coordinated on the interface 0013 An invention (8) provides a grease composition with a metal with ease and that the rod-like liquid crystal comprising the lubricant additive according to any one of the compound possessing a cation group and an anion forms a inventions (1) to (5). Smectic liquid crystal phase due to the powerful vertical 0014. An invention (9) provides the grease composition sequence and exists in a dark field when observed by a polar according to the invention (8), wherein the content of the ization microscope. The inventor has found that due to Such lubricant additive is 0.0001 to 0.1 mass %. characteristics, the positive (+) and negative (-) portions of 0015. An invention (10) provides a grease composition ions of the rod-like liquid crystal compound possessing a comprising the lubricant composition according to the inven cation group and an anion on the interface with a metal bond tion (6) or (7) and a thickener. US 2009/0239773 A1 Sep. 24, 2009 0016. The lubricant additive of the present invention can 0023 The cation group in the lubricant additive of the reduce the friction coefficient when added in a small amount. present invention is not particularly limited. Examples Since the lubricant additive of the present invention is an include a Sulfonium group, a phosphonium group, an ammo ionized liquid crystal compound, the boiling point of the nium group, a Serenonium group, an arsonium group, a sti lubricant composition is increased if the lubricant additive is bonium group, a stanonium group, an iodonium group, and a added in a small amount. Thus, the effects of controlling nitrogen-containing heterocyclic quaternary base. As the vaporization and lowering the coagulation temperature of the nitrogen-containing heterocyclic quaternary base, a pyri lubricant composition can also be expected. The lubricant dinium group, an imidazolium group, a thiozolium group, an composition and the grease composition containing the lubri Oxazolium group, a pyradinium group, a pyrimidinium group. cant additive of the present invention are useful for lubricat and the like can be given. The nitrogen-containing heterocy ing vehicle components such as continuously variable trans clic quaternary base may be substituted with a hetero atom missions, manual or automatic transmissions, engines, gears, Such as an oxygen atom and a Sulfur atom, and may form a and power steering, for lubricating internal combustion ring. Of these, the pyridinium group or the ammonium group engines, machine tools, and the like, and for lubricating is preferable. Although there are no particular limitations to motors and sliding parts of precision mechanical equipment the valence number of the cation group in the lubricant addi Such as a computer hard disk, information recording media tive of the present invention, a monovalent cation group is Such as a tape and a card, and a cellular phone. preferable. That is to say, as the rod-like liquid crystal com pound used as the lubricant additive of the present invention, BRIEF DESCRIPTION OF THE DRAWINGS a pyridinium salt or an ammonium salt is preferable. 0017 FIG. 1 shows the state of the lubricant additive of the 0024. There are no specific limitations to the anion in the present invention on a metal surface and FIG. 2 shows the lubricant additive of the present invention. Halogen ions such change of the friction coefficient over time in Example 3, as a chlorine ion, a bromine ion, and an iodine ion, anions of Example 4, and Comparative Example 1.