Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic oxygen compound
Reexamination Certificate
2000-03-14
2002-06-11
McAvoy, Ellen M. (Department: 1704)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic oxygen compound
C568S678000, C568S679000, C568S680000, C568S625000
Reexamination Certificate
active
06403541
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an agent capable of significantly alleviating oil filter clogging caused by water mixed in an engine oil, the agent comprising a nonionic surfactant or a hydroxyl-containing component; a method for preventing oil filter clogging using the agent; and an engine oil composition containing the agent.
PRIOR ART
Recent engines have higher output, improved fuel efficiency, and improved combustion process that meets exhaust gas regulations, and thus high performance characteristics are required of engine oils. For achieving the required performance characteristics, new techniques for formulating additives are necessary. Among the required performance characteristics is anti-clogging properties for oil filters.
Oil filter clogging occurs as follows: When moisture in a blowby gas is condensed and mixed in an engine oil, additives dissolved in the oil are affected, and separate from the oil or form foots-like or mayonnaise-like sludge, making the oil difficult to pass through the filter. Oil filter clogging obstructs oil circulation and is liable to cause troubles.
As an additive for preventing oil filter clogging, Japanese Unexamined Patent Publication No. 176583/1996 discloses a composition for improving demulsibility. Unexamined Patent Publication No. 176583/1996 discloses that demulsibility of diesel engine oils is improved by adding (A) an alkenyl succinimide or its derivative, (D) a surfactant and (C) calcium salicylate having a base number of at least 100 mg KOH/g, to a base stock which is a mineral oil or a synthetic oil or a mixture thereof.
Said publication discloses, as examples of the surfactant (D), polyoxyalkylamines wherein the alkyl group has 8-22 carbon atoms; polyoxyethylene alkyl or alkenyl ethers wherein the alkyl or alkenyl group has 10 to 20 carbon atoms; polyoxypropylene alkyl or alkenyl ethers wherein the alkyl or alkenyl group has 10 to 20 carbon atoms; polyoxyethylene alkylphenyl ethers wherein the alkyl group has 6 to 12 carbon atoms; and the like.
However, said publication discloses that the three components, i.e., (A) an alkenyl succinimide or its derivative, (D) a surfactant and (C) calcium salicylate having a base number of at least 100 mg KOH/g, are essential for improving demulsibility, and does not disclose that single use of the surfactant (D) is effective for improving demulsibility.
Further, among the surfactants disclosed as specific examples of the surfactant (D), only polyoxyethylene nonylphenyl ether is used in the working examples.
Moreover, even if demulsibility is improved, oil filter clogging occurs in many cases. For example, although the engine oil composition disclosed in Japanese Unexamined Patent Publication No. 176583/1996 can improve demulsibility, water is not removed from the composition and therefore separated water is liable to redisperse in the composition. It is presumed that the redispersed water will form foots-like sludge and makes it difficult to sufficiently prevent oil filter clogging. Consequently, an additive capable of inhibiting formation of foots-like or mayonnaise-like sludge would be extremely useful because such an additive would significantly alleviate oil filter clogging and solve the above problems.
DISCLOSURE OF THE INVENTION
In view of the above state of the prior art, an object of the present invention is to provide an agent for preventing oil filter clogging, the agent being capable of inhibiting formation of foots-like or mayonnaise-like sludge when water is mixed in an engine oil, to thereby significantly prevent oil filter clogging.
The present inventors carried out extensive research to achieve the above object, and found that a specific nonionic surfactant or a hydroxyl-containing component, when added to an engine oil, can significantly prevent oil filter clogging. The present invention has been accomplished based on this finding.
The present invention provides an agent for preventing oil filter clogging, the agent comprising at least one hydroxyl-containing component selected from the group consisting of:
polyoxyalkylene ethers represented by the formula (1)
R
1
O—(R
2
O)m—H (1)
wherein R
1
is hydrogen or C
1
to C
8
alkyl, R
2
is C
2
to C
10
alkylene, m is an integer of 1 to 10, and when m is 2 or more, the two or more R
2
groups may be the same or different; and
polyoxyalkylene glyceryl ethers represented by the formula (2)
wherein R
3
is C
2
to C
4
alkylene, R
4
is hydrogen or C
1
to C
10
alkyl, n is an integer of 0 to 8, and when n is 2 or more, the two or more R
3
groups may be the same or different.
The present invention also provides an engine oil composition containing an agent for preventing oil filter clogging, the agent comprising at least one hydroxyl-containing component selected from the group consisting of:
polyoxyalkylene ethers represented by the formula (1)
R
1
O—(R
2
O)m—H (1)
wherein R
1
, R
2
and m are as defined above; and
polyoxyalkylene glyceryl ethers represented by the formula (2)
wherein R
3
, R
4
and n are as defined above.
The present invention further provides a method for preventing oil filter clogging, the method comprising adding to an engine oil at least one hydroxyl-containing component selected from the group consisting of:
polyoxyalkylene ethers represented by the formula (1)
R
1
O—(R
2
O)m—H (1)
wherein R
1
, R
2
and m are as defined above; and
polyoxyalkylene glyceryl ethers represented by the formula (2)
wherein R
3
, R
4
and n are as defined above.
DETAILED DESCRIPTION OF THE INVENTION
Agent for Preventing Oil Filter Clogging
The agent for preventing oil filter clogging according to the present invention comprises at least one nonionic surfactant or hydroxyl-containing component selected from the group consisting of:
polyoxyalkylene ethers represented by the formula (1)
R
1
O—(R
2
O)m—H (1)
wherein R
1
, R
2
and m are as defined above; and
polylxyalkylene glyceryl ethers represented by the formula (2)
wherein R
3
, R
4
and n are as defined above.
Polyoxyalkylene Ethers of the Formula (1)
In the polyoxylalkylene ethers represented by the formula (1), R
1
is hydrogen or C
1
to C
8
alkyl, m is an integer of 1 to 10, and R
2
may be the same or different and represents C
2
to C
10
alkylene. That is, R
2
represents C
2
to C
10
alkylene, and when m is 2 or more, the two or more R
2
groups may be the same or different.
It is recommended that R
1
is hydrogen, straight-chain C
1
to C
8
alkyl or branched-chain C
3
to C
8
alkyl.
Preferably, R
1
is hydrogen, straight-chain C
1
to C
8
alkyl or branched-chain C
3
to C
8
alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, 2-methylhexyl, n-octyl, 1-methylheptyl, 2-methylheptyl, 2-ethylhexyl, 2-octyl or isooctyl.
R
2
is, for example, straight-chain or branched-chain C
2
to C
10
alkylene, in particular straight-chain C
2
to C
8
alkylene or branched-chain C
3
to C
8
alkylene. The number of oxyalkylene group or groups represented by m is 1 to 10 and is sometimes expressed in terms of the average value.
Specific species of C
2
to C
10
alkylene represented by R
2
include ethylene, propylene, isopropyrene, butylene, isobutylene, pentylene, hexylene, octylene, nonylene, decylene and the like.
The polyoxyalkylene ethers represented by the formula (1) can be classified into polyoxyalkylene ethers represented by the formula (3)
R
5
O—(R
6
O)x—(R
7
O)y—H (3)
wherein R
5
has the same meaning as R
1
; R
6
and R
7
may be the same or different and each represents C
2
to C
4
alkylene; and x and y may be the same or different and each are an integer of 0 to 10, provided that 1≦x+y≦10; and
polyoxyalkylene ethers represented by the formula (4)
R
8
O—(R
9
O)x1—(R
10
O)z—(R
11
O)y1—H (4)
wherein R
8
has the same meaning as R
1
; R
9
and R
11
may be the same or different and each represents C
2
to C
4
alkylene; R
Kambara Yoshikuni
Tomizawa Hirotaka
Armstrong Westerman & Hattori, LLP
McAvoy Ellen M.
New Japan Chemical Co. Ltd.
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