JPH04309598A - Viscosity index improver for automatic transmission oil - Google Patents

Abstract

PURPOSE:To give an ability to disperse sludge to a viscosity index improver for automatic transmission oil. CONSTITUTION:An excellent ability to disperse sludge can be given by using a copolymer of a dialkylaminoalkyl(meth)acrylamide and a 6C or higher alkyl (meth)acrylate.

Description

Description: TECHNICAL FIELD The present invention relates to a viscosity index improver used in automatic transmission oil for automobiles. 2. Description of the Related Art As automobiles become smaller and have higher output, automatic transmission oils are exposed to severe thermal conditions and become less expensive due to the generation of sludge and the like. Therefore, it is desired that the viscosity index improver used in these products also has the effect of dispersing sludge. Various methods are known for providing viscosity index improvers with the function of dispersing sludge, mainly for engine oils, but these methods do not necessarily have sufficient effects when used for automatic transmission oils. do not. This is because additives other than the viscosity index improver used for this purpose are different from engine oil. [0003] However, it has been discovered that certain copolymers exhibit sufficient sludge dispersibility even when used in combination with additives other than viscosity index improvers for automatic transmission oils. Ta. [Means for Solving the Problem] That is, the present invention provides a viscosity for automatic transmission oil characterized by comprising a copolymer having the following components (A) and (B) as essential constituent units. It is an index improver. (A) component: dialkylaminoalkyl (meth)acrylamide (B) component: (meth)acrylic acid ester of aliphatic alcohol having 6 or more carbon atoms [0005] Dialkylaminoalkyl (meth) constituting the copolymer of the present invention Acrylamide is represented by general formula (1). (Here, R1 and R2 are the same or different alkyl groups, R3 is an alkylene group having 2 or more carbon atoms, and R4 is a hydrogen atom or a methyl group.) Representative compounds represented by the general formula (1) Examples include dimethylaminoethyl acrylamide, diethylaminoethyl acrylamide, dimethylaminopropylacrylamide, dibutylaminopropylacrylamide, dioctylaminoethylacrylamide, dilaurylaminopropylacrylamide, and methacrylamide corresponding to these acrylamides and mixtures thereof. be. Typical examples of component (B) used in the present invention include hexyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol,
These are esters of acrylic acid or methacrylic acid such as dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, cyclohexyl alcohol, and benzyl alcohol, and include mixtures of one or more of these esters. The viscosity index improver of the present invention is usually obtained by copolymerizing component (A) in an amount of 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight, per 100 parts by weight of component (B). be. The viscosity index improver of the present invention is copolymerized with components (A) and (B) as essential components, but other components can be used as necessary. Examples of these other components include other nitrogen-containing vinyl monomers (N-vinylpyrrolidone, N-vinylthiopyrrolidone, dialkylaminoalkyl methacrylate, morpholinoethyl methacrylate, N -vinylimidazoles, etc.), and non-vinyl compounds containing nitrogen, etc. (phenothiazines, imidazoles, thiazoles, benzothiazoles, triazoles, thiazorindines, pyrimidines, pyridines, piperidines) , pyrrolidinones, oxazoles, thiomorpholines, etc.) can also be grafted. Examples of other compounds that can be used with component (B) include esters of aliphatic alcohols having 5 or fewer carbon atoms and acrylic acid or methacrylic acid (methyl acrylate, methyl methacrylate, propyl methacrylate, butyl acrylate, amyl methacrylate, etc.); Examples include vinyl aromatic compounds (styrene, vinyltoluene, etc.). In the case of other nitrogen-containing compounds used together with component (A), the amount of these optional components to be used is 100 parts by weight or less, preferably 50 parts by weight, per 100 parts by weight of component (A).
Parts by weight or less. In addition, in the case of a (meth)acrylic acid ester or vinyl aromatic compound having an alkyl group having 5 or less carbon atoms to be used together with component (B), 50 parts by weight or less per 100 parts by weight of component (B). , preferably 3
It is 0 parts by weight or less. The viscosity index improver of the present invention can be easily obtained by conventional methods. For example, component (A) and (
It is obtained by radical polymerizing component B) in mineral oil or a solvent. In this case, an azo type (azobisisobutyronitrile, azobisvaleronitrile, etc.) or a peroxide type (benzoyl peroxide, cumyl peroxide, lauryl peroxide, etc.) is used as a polymerization catalyst. When graft copolymerizing component (A), it is preferable to use a peroxide type. In the viscosity index improver of the present invention, both a random copolymer and a graft copolymer of components (A) and (B) have excellent effects, but the graft copolymer is more excellent. It is preferable because it shows good sludge dispersibility. There is also a preferable range for the molecular weight. If the molecular weight is too large, the viscosity index improver cannot resist mechanical ∇ shearing force and the polymer chains break, making it impossible to maintain the required viscosity for a long period of time. Furthermore, if the molecular weight is too small, the required viscosity cannot be obtained unless a large amount of an expensive viscosity index improver is used. Usually, the weight average molecular weight is 3
The range is from 10,000 to 200,000, preferably from 50,000 to 150,000. The amount of the viscosity index improver used in the present invention depends on the viscosity of the added mineral oil, etc., but is usually 2% to 20%, preferably 4% to 10%, based on the polymer content. The viscosity index improver of the present invention exhibits excellent effects when used in automatic transmission oil for automobiles. The automatic transmission oil here is generally called torque converter oil, and is a hydraulic oil for automatic transmissions. The viscosity index improver of the present invention may contain other optional ingredients such as detergents (sulfonate, salicylate, etc.).
phenate-based, naphthenate-based, etc.), dispersants (isobutenyl succinimide-based, Mannich condensate-based, etc.)
, antioxidants (zinc dithiophosphate, amine-based,
Even if it contains oil-based agents (fatty acid-based, fatty acid ester-based, etc.), friction and wear modifiers (molybdenum dithiophosphate, molybdenum carbamate, etc.), extreme pressure agents (sulfur-phosphorus-based, chlorine-based, etc.) good. [0014] The present invention will be explained in detail with reference to Examples below, but the present invention is not limited thereto. In addition, all molecular weights in the examples represent weight average molecular weights, and % represents weight %. (Synthesis Example 1) 150 g of mineral oil was placed in a 1-liter glass reactor equipped with a stirrer, thermometer, and condenser, and after replacing the air in the reactor with nitrogen,
While raising the temperature to 70 degrees and flowing a small amount of nitrogen, a mixture of 70 g of methyl methacrylate, 7 g of dimethylaminopropyl methacrylamide, 250 g of lauryl methacrylate, 23 g of octadecyl methacrylate, 1.7 g of azobisisobutyronitrile, and 2.0 g of lauryl mercaptan was added. Polymerization was carried out at the same temperature for 2 hours while dropping. after that,
In order to complete the polymerization, the temperature was raised to 100 degrees Celsius, and the polymerization was continued for an additional 3 hours. As a result, a random copolymer with a molecular weight of 70,000 was obtained. (Synthesis Example 2) 150g of mineral oil was placed in a reactor similar to that used in Synthesis Example 1, and 70g of methyl methacrylate, 250g of lauryl methacrylate, 23g of octadecyl methacrylate, and 1 benzoyl peroxide were added in the same manner as in Synthesis Example 1. .3g, lauryl mercaptan2.
Polymerization was carried out by dropping 0 g of the mixture over 2 hours. After further polymerization for 1 hour at the same temperature, 7 g of dimethylaminopropyl methacrylamide and 0.0 g of benzoyl peroxide were added.
5 g was added and polymerized at the same temperature for 3 hours. As a result, a graft copolymer with a molecular weight of 90,000 was obtained. (Synthesis Example 3) A random copolymer with a molecular weight of 65,000 consisting of 70 g of butyl methacrylate, 7 g of diethylaminoethyl acrylamide, 100 g of decyl acrylate, 150 g of lauryl methacrylate, and 23 g of octadecyl methacrylate was obtained in the same manner as in Synthesis Example 1. Ta. (Synthesis Example 4) A random copolymer with a molecular weight of 100,000 consisting of 70 g of methyl methacrylate, 15 g of dibutylaminoethyl methacrylamide, 30 g of styrene, 150 g of lauryl methacrylate, and 85 g of hexadecyl methacrylate was obtained in the same manner as in Synthesis Example 1. Ta. (Synthesis Example 5) A random copolymer of 70 g of methyl methacrylate, 5 g of dimethylaminopropyl methacrylamide, 2 g of morpholinoethyl methacrylate, 250 g of lauryl methacrylate, and 23 g of octadecyl methacrylate with a molecular weight of 90,000 was prepared in the same manner as in Synthesis Example 1. Obtained union. (Synthesis Example 6) A random copolymer having a molecular weight of 90,000 and consisting of 70 g of methyl methacrylate, 7 g of vinyl pyrrolidone, 250 g of lauryl methacrylate, and 23 g of octadecyl methacrylate was obtained in the same manner as in Synthesis Example 1. (Synthesis Example 7) A random copolymer having a molecular weight of 80,000 and consisting of 70 g of methyl methacrylate, 7 g of morpholinoethyl methacrylate, 250 g of lauryl methacrylate, and 23 g of octadecyl methacrylate was obtained in the same manner as in Synthesis Example 1. (Synthesis Example 8) A random copolymer having a molecular weight of 100,000 and consisting of 70 g of methyl methacrylate, 7 g of dimethylaminoethyl methacrylate, 250 g of lauryl methacrylate, and 23 g of octadecyl methacrylate was obtained in the same manner as in Synthesis Example 1. (Example) 10% of the copolymers of Synthesis Examples 1 to 8, 8% of automatic transmission oil package additive (manufactured by Exxon, ECA4700),
A mixture of 82% mineral oil was prepared and tested for antioxidant properties (JIS
K2514) for 96 hours. As a result, the results shown in Table 1 were obtained. [Table 1] Antioxidant test
｜ Pentane insoluble content (%)
Sample −−−−−
−−−−−−−−−−−−−−−−−
｜
Method A Method B Method B-Method A −−−−−−−−−−−−−−−−−−
−−−−−−−−−−−−−−− Real | Synthesis Example 1 | 0.11
0.32 0.21
2
0.04
0.33 0.29
Example | 3 |
0.15 0.35
0.20
4 0
．． 15 0.33
0.18 |
5 | 0.15
0.37 0.
22 −−−−−−−−−−−−−−−−−
−−−−−−−−−−−−−−−−− Ratio
|Synthesis Example 6 | 0.76
0.86 0.
10 comparison 7
1.16
1.23 0.07
Example | 8 |
1.05 1.12
0.07 [0025] In the table, method A is the amount of sludge obtained by centrifuging the oil after the test, and method B is the amount of sludge obtained by centrifuging the oil after the test. This is the amount of sludge obtained. Therefore, the difference between Method A and Method B indicates the sludge dispersion ability. Furthermore, the amount of sludge in Method A and Method B indicates antioxidant properties, and the smaller the amount, the better the performance. Effects of the Invention When the viscosity index improver of the present invention is used in automatic transmission oil, it can be used in combination with other additives (usually packaged) other than the viscosity index improver for this purpose, resulting in extremely In addition to exhibiting excellent sludge dispersibility, it also has the effect of reducing the amount of sludge generated.

Claims (2)

[Claims] 1. A viscosity index improver for automatic transmission oil, comprising a copolymer having the following components (A) and (B) as essential constituent units. (A) Component: dialkylaminoalkyl (meth)acrylamide (B) component: (meth)acrylic acid ester of aliphatic alcohol having 6 or more carbon atoms 2. The copolymer according to claim 1, wherein the copolymer is a copolymer obtained by graft-polymerizing a monomer containing component (A) as a main component to a polymer obtained by polymerizing component (B). Viscosity index improver.