Lithium Grease Composition Sealed in a Small Motor Bearing to Reduce Noise

Abstract

A lithium grease composition which can be sealed in a small motor bearing to reduce noise, composed of 5-20% by weight of a thickener and 95-80% by weight of a base oil, wherein said grease composition adopts lithium soap as the thickener, which is synthesized from lithium hydroxide and a higher fatty acid with 10 to 20 carbon atoms and/or a higher hydroxyfatty acid with one or more hydroxyl groups and 10 or more carbon atoms, and the base oil includes, as a main component, a polymer ester oil (A) in which 8 or more ester groups are arranged in a comb tooth form on one side of chain molecules constituted by eight or more carbon atoms which is expressed by general formula 1: (In the formula, each of R 1 , R 2 , R 3 and R 4 is an alkyl group, where x is an integer and x≧2, and y is an integer and y≧2.) and the base oil (40 C) has a viscosity of 25 to 80 mm 2 /s.

1 . A lithium grease composition sealed in a small motor bearing to reduce noise comprising:
 a) more than 5% to less than 20% by weight of a lithium soap thickener;   b) said thickener synthesized from lithium hydroxide and
 i) a higher fatty acid with 10 to 20 carbon atoms or 
 ii) a higher hydroxyfatty acid with one or more hydroxyl groups and 10 or more carbon atoms, or 
 iii) both i and ii; 
   c) 95 to 80% by weight of a base oil;   d) said base oil including a polymer ester oil in which 8 or more ester groups are arranged in a comb tooth form on one side of chain molecules which is expressed by Formula 1   
     
       
         
         
             
             
         
       
     
     (where each of R 1 , R 2 , R 3  and R 4  represents an alkyl group, x is an integer satisfying x≧2, and y is an integer satisfying y≧2) 
     and said base oil having a viscosity (40° C.) of 25 to 80 mm 2 /s. 
   
   
       2 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 1 , further comprising said base oil including a synthetic ester oil. 
   
   
       3 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 1 , further comprising said base oil including a synthetic hydrocarbon oil. 
   
   
       4 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 1 , further comprising said base oil including a synthetic ether oil. 
   
   
       5 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 2  further comprising said base oil including a synthetic ether oil. 
   
   
       6 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 3  further comprising said base oil including a synthetic ether oil. 
   
   
       7 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 3  further comprising said base oil including a synthetic ester oil. 
   
   
       8 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 1  further comprising said base oil including a synthetic ester oil, a synthetic hydrocarbon oil and a synthetic ether oil. 
   
   
       9 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 1  wherein the base oil includes one or more of the oils selected from the group of a synthetic ester oil, a synthetic hydrocarbon oil and synthetic ether oil. 
   
   
       10 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claims 8  wherein polymer ester oil accounts for 20 to 50% by weight of the total of the grease composition, synthetic ester oil accounts for 10 to 45% by weight of the total of the grease composition, and synthetic ether oil accounts for 10 to 45% by weight of the total of the grease composition. 
   
   
       11 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claims 8  or  9  wherein polymer ester oil accounts for 20 to 50% by weight of the total of the grease composition, synthetic ester oil accounts for 10 to 45% by weight of the total of the grease composition, and synthetic hydrocarbon oil accounts for 5 to 45% by weight of the total of the grease composition. 
   
   
       12 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claims 8  or  9  wherein said polymer ester oil accounts for 20 to 50% by weight of the total of the grease composition, said synthetic ester oil accounts for 10 to 45% by weight of the total of the grease composition, said synthetic hydrocarbon oil accounts for 5 to 15% by weight of the total of the grease composition, and said synthetic ether oil accounts for 10 to 30% by weight of the total of the grease composition. 
   
   
       13 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claims 1  to  9  wherein said lithium soap is a mixture of a 12-hydroxystearic acid lithium soap and a straight-chain fatty acid lithium soap (with 10 to 20 carbon atoms), said 12-hydroxystearic acid lithium soap accounts for 2.5 to 10% by weight of the total of the grease composition, and said straight-chain fatty acid lithium soap (with 10 to 20 carbon atoms) accounts for 2.5 to 10% by weight of the total of the grease composition. 
   
   
       14 . The lithium grease composition sealed in a small-motor bearing to reduce noise according to any one of  claims 1  to  9  further comprising said grease composition includes an antioxidant or an anticorrosive agent or both an antioxidant and an anticorrosive agent. 
   
   
       15 . The lithium grease composition sealed in a small motor bearing to reduce noise according to any one of  claims 1  to  9  wherein said polymer ester oil is present in an amount of 20 to 50% by weight of said grease. 
   
   
       16 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claims 1  to  9  wherein in d) said polymer ester oil is present in a significant amount of 20% or greater by weight of said base oil. 
   
   
       17 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claims 1  to  9  wherein in d) said polymer ester oil has a molecular weight of 1000 to 3000 and a viscosity (40° C.) of 100 to 245 mm 2 /s. 
   
   
       18 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 9  wherein said synthetic ester oil is
 a) a synthetic diester oil having the formula:
   RCOOH(CH 2 ) n COOR′ 
   (where R and R′ represent alkyl groups with 3 to 18 carbon atoms, and can be identical or different from each other, and n is 3 to 12.);   b) a synthetic trimester oil having the formula
   R(CH 2 COO R′) 3    
   (where R and R′ represent alkyl groups with 3 to 10 carbon atoms);   c) a synthetic tetraester oil having the formula
   R(CH 2 COOR′) 4    
   
     (where R and R′ represent alkyl groups with 3 to 10 carbon atoms); or
 d) a synthetic neopentyl polyol ester oil. 
 
   
   
       19 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 9  wherein said synthetic hydrocarbon oil is a poly-α-olefin oil or a polybutene and olefin copolymer, that has a viscosity (40° C.) of 20 to 100 mm 2 /s. 
   
   
       20 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 9  wherein said synthetic ether oil (D) is an alkyl diphenyl ether. 
   
   
       21 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 20  wherein said synthetic ether oil (D) is dialkyl diphenyl ether, monoalkyl diphenyl ether, or a mixture thereof. 
   
   
       22 . The lithium grease composition sealed in a small motor bearing to reduce noise according to any one of  claims 1  to  10  wherein the lithium soap thickener is about 7.5% to about 17.5% by wt. 
   
   
       23 . The lithium grease composition sealed in a small motor bearing to reduce noise according to any one of  claims 1  to  10  wherein the lithium soap thickener is about 10% to about 15% by wt. 
   
   
       24 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 11  wherein the lithium soap thickener is about 7.5% to about 17.5% by wt. 
   
   
       25 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 11  wherein the lithium soap thickener is about 10% to about 15% by wt. 
   
   
       26 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 12  wherein the lithium soap thickener is about 7.5% to about 17.5% by wt. 
   
   
       27 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 12  wherein the lithium soap thickener is about 10% to about 15% by wt. 
   
   
       28 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 24  wherein in d) said polymer ester oil has a molecular weight of 1000 to 3000 and a viscosity (40° C.) of 100 to 245 mm 2 /s. 
   
   
       29 . The lithium grease composition sealed in a small motor bearing to reduce noise according to  claim 26  wherein in d) said polymer ester oil has a molecular weight of 1000 to 3000 and a viscosity (40° C.) of 100 to 245 mm 2 /s. 
   
   
       30 . A lithium grease composition comprising:
 a) more than 5% to less than 20% by weight of a lithium soap thickener;   b) said thickener synthesized from lithium hydroxide and
 i) a higher fatty acid with 10 to 20 carbon atoms or ii) a higher hydroxyfatty acid with one or more hydroxyl groups and 10 or more carbon atoms, or 
 iii) both i and ii; 
   c) 95 to 80% by weight of a base oil;   d) said base oil including a polymer ester oil in which 8 or more ester groups are arranged in a comb tooth form on one side of chain molecules which is expressed by Formula 1   
     
       
         
         
             
             
         
       
     
     (where each of R 1 , R 2 , R 3  and R 4  represents an alkyl group, x is an integer satisfying x≧2, and y is an integer satisfying y≧2) 
     and said base oil having a viscosity (40° C.) of 25 to 80 mm 2 /s. 
   
   
       31 . The lithium grease composition according to  claim 30  further comprising said base oil including a synthetic ester oil. 
   
   
       32 . The lithium grease composition according to  claim 30  further comprising said base oil including a synthetic hydrocarbon oil. 
   
   
       33 . The lithium grease composition according to  claim 30  further comprising said base oil including a synthetic ether oil. 
   
   
       34 . The lithium grease composition according to  claim 31  further comprising said base oil including a synthetic ether oil. 
   
   
       35 . The lithium grease composition according to  claim 32  further comprising said base oil including a synthetic ether oil. 
   
   
       36 . The lithium grease composition according to  claim 32  further comprising said base oil including a synthetic ester oil. 
   
   
       37 . The lithium grease composition according to  claim 30  further comprising said base oil including a synthetic ester oil, a synthetic hydrocarbon oil and a synthetic ether oil. 
   
   
       38 . The lithium grease composition according to  claim 30  wherein the base oil includes one or more of the oils selected from the group of a synthetic ester oil, a synthetic hydrocarbon oil and synthetic ether oil. 
   
   
       39 . The lithium grease composition according to  claim 37  wherein polymer ester oil accounts for 20 to 50% by weight of the total of the grease composition, synthetic ester oil accounts for 10 to 45% by weight of the total of the grease composition, and synthetic ether oil accounts for 10 to 45% by weight of the total of the grease composition. 
   
   
       40 . The lithium grease composition according to  claims 37  or  38  wherein polymer ester oil accounts for 20 to 50% by weight of the total of the grease composition, synthetic ester oil accounts for 10 to 45% by weight of the total of the grease composition, and synthetic hydrocarbon oil accounts for 5 to 45% by weight of the total of the grease composition. 
   
   
       41 . The lithium grease composition according to  claims 37  or  38  wherein said polymer ester oil accounts for 20 to 50% by weight of the total of the grease composition, said synthetic ester oil accounts for 10 to 45% by weight of the total of the grease composition, said synthetic hydrocarbon oil accounts for 5 to 15% by weight of the total of the grease composition, and said synthetic ether oil accounts for 10 to 30% by weight of the total of the grease composition. 
   
   
       42 . The lithium grease composition according to  claims 30  to  38  wherein said lithium soap is a mixture of a 12-hydroxystearic acid lithium soap and a straight-chain fatty acid lithium soap (with 10 to 20 carbon atoms), said 12-hydroxystearic acid lithium soap accounts for 2.5 to 10% by weight of the total of the grease composition, and said straight-chain fatty acid lithium soap (with 10 to 20 carbon atoms) accounts for 2.5 to 10% by weight of the total of the grease composition. 
   
   
       43 . The lithium grease composition according to any one of  claims 30  to  38  further comprising said grease composition includes an antioxidant or an anticorrosive agent or both an antioxidant and an anticorrosive agent. 
   
   
       44 . The lithium grease composition according to any one of  claims 30  to  38  wherein said polymer ester oil is present in an amount of 20 to 50% by weight of said grease. 
   
   
       45 . The lithium grease composition according to  claims 30  to  38  wherein in d) said polymer ester oil is present in a significant amount of 20% or greater by weight of said base oil. 
   
   
       46 . The lithium grease composition according to  claims 30  to  38  wherein in d) said polymer ester oil has a molecular weight of 1000 to 3000 and a viscosity (40° C.) of 100 to 245 mm 2 /s. 
   
   
       47 . The lithium grease composition according to  claim 38  wherein said synthetic ester oil is
 a) a synthetic diester oil having the formula:
   RCOOH(CH 2 ) n COOR′ 
   (where R and R′ represent alkyl groups with 3 to 18 carbon atoms, and can be identical or different from each other, and n is 3 to 12.);   b) a synthetic trimester oil having the formula:
   R(CH 2 COOR′) 3    
   (where R and R′ represent alkyl groups with 3 to 10 carbon atoms);   c) a synthetic tetraester oil having the formula:
   R(CH 2 COOR′) 4    
   (where R and R′ represent alkyl groups with 3 to 10 carbon atoms); or   d) a synthetic neopentyl polyol ester oil.   
   
   
       48 . The lithium grease composition according to  claim 38  wherein said synthetic hydrocarbon oil is a poly-α-olefin oil or a polybutene and olefin copolymer, that has a viscosity (40° C.) of 20 to 100 mm 2 /s. 
   
   
       49 . The lithium grease composition according to  claim 38  wherein said synthetic ether oil (D) is an alkyl diphenyl ether. 
   
   
       50 . The lithium grease composition according to  claim 49  wherein said synthetic ether oil (D) is dialkyl diphenyl ether, monoalkyl diphenyl ether, or a mixture thereof. 
   
   
       51 . The lithium grease composition according to any one of  claims 30  to  39  wherein the lithium soap thickener is about 7.5% to about 17.5% by wt. 
   
   
       52 . The lithium grease composition according to any one of  claims 30  to  39  wherein the lithium soap thickener is about 10% to about 15% by wt. 
   
   
       53 . The lithium grease composition according to  claim 40  wherein the lithium soap thickener is about 7.5% to about 17.5% by wt. 
   
   
       54 . The lithium grease composition according to  claim 40  wherein the lithium soap thickener is about 10% to about 15% by wt. 
   
   
       55 . The lithium grease composition according to  claim 41  wherein the lithium soap thickener is about 7.5% to about 17.5% by wt. 
   
   
       56 . The lithium grease composition according to  claim 41  wherein the lithium soap thickener is about 10% to about 15% by wt. 
   
   
       57 . The lithium grease composition according to  claim 53  wherein in d) said polymer ester oil has a molecular weight of 1000 to 3000 and a viscosity (40° C.) of 100 to 245 mm 2 /s. 
   
   
       58 . The lithium grease composition according to  claim 55  wherein in d) said polymer ester oil has a molecular weight of 1000 to 3000 and a viscosity (40° C.) of 100 to 245 mm 2 /s.