JPH0881690A - Oil non-diffusion additive - Google Patents

Abstract

(57) [Summary] [Field of the Invention] An oil non-diffusion additive comprising a fluorine-based copolymer having a perfluoroalkyl group having 3 to 21 carbon atoms and a polyoxypropylene unit having 1 to 10 repeating units. [Effect] By adding the oil non-diffusion additive of the present invention to a grease, a low-viscosity base oil made of a synthetic lubricating oil used to satisfy the performance required of the grease diffuses from the coated surface. Can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil non-diffusion additive for preventing the diffusion of base oil in grease used for mechanical rotating parts and sliding parts of various precision instruments.

[0002]

2. Description of the Related Art With the rapid improvement in performance and miniaturization of various equipment, the grease used in its mechanical rotating and sliding parts is required to have better characteristics than before. It's starting to happen. That is, the performance required for the grease used for various miniaturized various mechanical parts, motors, various bearings, contacts, switches, etc. is heat resistance, low temperature stability, and light torque property.

In order to satisfy these performances, commercially available greases are prepared by dispersing a thickening agent such as urea or soap in a base oil consisting of a low-viscosity synthetic lubricating oil. However, in such a conventional grease, since the synthetic lubricating oil as described above is used as the base oil, the oil content or the oily additive in the grease component after the grease application is
There is a problem that it diffuses (exudes) from the coated surface over time.

A method for preventing the diffusion of the base oil is Japanese Patent Publication No.
-46999. Its content is to suppress diffusion of base oil by adding a fluorosurfactant having a perfluorocarbon chain as a hydrophobic group and having oxyethylene as a hydrophilic group to a grease having a synthetic lubricating oil as a base oil. Is.

However, this method still cannot completely prevent the base oil from diffusing on the base material, and in the long term, the base oil gradually diffuses to cause metal,
It may adversely affect the base material such as plastic, and may eventually cause fatal damage to the product such as defective operation and defective conductivity.

Therefore, recently, it has been desired to develop an additive capable of completely preventing the diffusion of the base oil in the grease.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to solve such problems, to prevent the diffusion (exudation) of base oil during the product life of precision machinery used, and to provide heat resistance. ,
An object of the present invention is to provide a base oil diffusion inhibitor for grease that can maintain the original properties of grease such as low temperature stability and light torque.

[0008]

The inventors of the present invention have made diligent studies in view of the above situation. As a result, even in the case of a grease using a synthetic lubricating oil as a base oil, the grease contains a perfluoroalkyl group and a polyoxyalkyl group. It has been found that the addition of a copolymer composition having a propylene unit can completely suppress the diffusion of base oil, thus completing the present invention.

That is, the present invention relates to an additive for non-diffusion of oil which comprises a fluorine-based copolymer having a perfluoroalkyl group and a polyoxypropylene unit.
The base oil diffusion inhibitor of the present invention is a base oil diffusion inhibitor of grease, and specifically, it is added to a grease having a synthetic lubricating oil as a base oil and a thickening agent such as urea or soap. is there.

The fluorocopolymer having a perfluoroalkyl group and a polyoxypropylene unit of the present invention is a perfluoroalkyl group-containing ethylenically unsaturated monomer (A) and a polyoxypropylene unit-containing ethylenically unsaturated monomer. It can be obtained by copolymerizing the monomer (B).

As the perfluoroalkyl group-containing ethylenically unsaturated monomer (A), any of known and conventional ones can be used. For example, (meth) acrylate having a fluorinated aliphatic group, vinyl ester, vinyl ether,
Examples thereof include malate, fumarate, and α-olefin. Note that (meth) acrylate is a generic term for methacrylate, acrylate, and fluoroacrylate.

Examples of the perfluoroalkyl group of the monomer (A) include a perfluoroalkyl group having 1 to 30 carbon atoms or a perfluoroalkenyl group, which may be linear, branched, cyclic or Any combination may be used. Further, the fluorinated aliphatic group may have an oxygen atom or a nitrogen atom in its main chain.

The perfluoroalkyl group-containing ethylenically unsaturated monomer (A) can be represented by, for example, the following general formula.

[0014]

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[Wherein R ₁ represents a perfluoroalkyl group having 1 to 30 carbon atoms, R represents a hydrogen atom or a methyl group, R'represents an alkylene group having 1 to 10 carbon atoms, and R " Represents a hydrogen atom or an alkyl group of 1 to 10, and Ph represents a phenyl group.] Specific examples of such a monomer (A) include the followings.

[0016]

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The monomer (A) is preferably a perfluoroalkyl group-containing ethylenically unsaturated monomer having a fluorine atom content of 5 to 80% by weight, and particularly 10 to 70% by weight. Furthermore, in order to sufficiently develop the diffusion (exudation) prevention effect when applied to a base material after being mixed with grease, a perfluoroalkyl group-containing ethylenically unsaturated monomer having 3 to 21 carbon atoms is used. It is preferable to use, and it is particularly preferable to use a perfluoroalkyl group-containing ethylenically unsaturated monomer having 6 to 12 carbon atoms.

The polyoxypropylene unit-containing ethylenically unsaturated monomer (B) according to the present invention is a monomer having an ethylenically unsaturated double bond at both ends or one end of a nonionic group. Examples thereof include a monomer having both a polyoxypropylene unit and an ethylenically unsaturated double bond at both ends or one end.

Such a monomer (B) can be represented by, for example, the following general formula.

[0020]

[Chemical 3]

As these monomers (B), those having a structure in which the number of repeating units of polyoxypropylene unit is 1 to 10 are used, and an additive copolymerized with the monomer (A) is added to the grease. In the case of, it is possible to mix quickly,
And more preferably also advantageous with respect to the base oil diffusion prevention rate immediately after applying the grease containing the additive to the base material,
Above all, the number of repeating units of polyoxypropylene group is 3 to
Those having the structure of 7 are particularly preferable in terms of the above-mentioned effects.

The copolymerization ratio of the monomer (A) and the monomer (B) is not particularly limited, but usually 5 to 200 parts by weight of the monomer (B) per 100 parts by weight of the monomer (A). Above all, in order to maintain the best balance between the orientation of the perfluoroalkyl group to the base material and the compatibility of the grease and the copolymer, the monomer (A) is used in an amount of 10 times the monomer (B). It is preferable to use ˜100 parts by weight.

As the ethylenically unsaturated monomer used in the additive for oil non-diffusion of the present invention, the above-mentioned monomers (A) and (B) are used as essential components depending on their use and purpose. Various monomers can be used. For example, in order to improve the compatibility of the polymerized copolymer with grease and to make the foaming property as low as possible, a non-fluorine-containing alkyl group other than a polyoxypropylene group-containing ethylenically unsaturated monomer is contained. A copolymer obtained by polymerizing the ethylenically unsaturated monomer (C) together is preferable.

The non-fluorine-containing alkyl group-containing ethylenically unsaturated monomer (C) referred to here is a monomer having both a non-fluorine-containing alkyl group and an ethylenically unsaturated double bond,
The alkyl group may have a linear structure, a branched structure, a cyclic structure, or any combination thereof.

Examples of such a monomer include the following alkyl (meth) acrylates having 1 to 30 carbon atoms, hydroxyl group-containing (meth) acrylate, and polydimethylsiloxyl group-containing (meth) acrylate. Can be mentioned.

Such a monomer (C) can be represented by, for example, the following general formula.

[0027]

[Chemical 4]

[0028]

[Chemical 5]

[0029]

[Chemical 6]

[0030]

[Chemical 7]

[0031]

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In addition to the above, as the monomer (C), an ethylenically unsaturated monomer containing a bridgehead in the molecule can also be used. For example, dicyclopentanyloxyethyl (meth) acrylate, isobornyloxyethyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, dimethyladamantyl (meth) acrylate, dicyclopentanyl (meth) acrylate, etc. Is mentioned.

The proportion of the copolymer of the monomer (C) is not particularly limited, but is usually 1 to 20 per 100 parts by weight of the monomer (A).
It is preferable to use 1 part by weight, especially 1 to 10 parts by weight.
In the case of obtaining an additive for oil non-diffusion having a remarkably excellent effect in all respects, a terpolymer obtained by using all of these monomers (A) to (C), or a monomer It is preferable to use an oil non-diffusion additive composed of a multicomponent copolymer obtained by polymerizing two or more kinds of all the components (A) to (C) or two or more kinds of arbitrary components.

The method for producing the oil non-diffusion additive comprising a fluorocopolymer having a perfluoroalkyl group and a polyoxypropylene unit according to the present invention is not limited at all, and a known method, that is, radical polymerization is used. It can be produced by a solution polymerization method, a bulk polymerization method, an emulsion polymerization method or the like based on a polymerization mechanism such as a legal method, a cationic polymerization method or an anionic polymerization method, but a radical polymerization method is particularly simple and industrially preferable.

In this case, as the polymerization initiator, those known in the art can be used, for example, peroxides such as benzoyl peroxide and diacyl peroxide, azobisisobutyronitrile, phenylazotriphenylmethane and the like. Azo compounds, metal chelate compounds such as Mn (acac) 3, and the like, and chain transfer such as lauryl mercaptan, 2-mercaptoethanol, ethylthioglycollic acid, and octylthioglycolic acid as necessary. It is possible to use an agent or a coupling group-containing thiol compound such as γ-mercaptopropyltrimethoxysilane together with a chain transfer agent.

The oil non-diffusion additive according to the present invention can also be obtained by photopolymerization in the presence of a photosensitizer or a photoinitiator, or by polymerization using radiation or heat as an energy source.

Examples of the solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol dibutyl ether, propylene glycol monomethyl ether and propylene glycol diethyl ether, acetone, methyl ethyl ketone, methyl isobutyl. Ketones, ketones such as cyclohexanone, ethers such as dimethyl ether and methyl ethyl ether, esters such as methyl acetate, ethyl acetate and butyl acetate, chlorine-based solvents such as chloroform, dichloroethane, perchloroethylene, carbon tetrachloride, hexane ,
Examples thereof include aliphatic hydrocarbons such as heptane, octane, terpene and kerosene, aromatic hydrocarbons such as toluene, xylene and benzene.

The copolymer thus obtained may be solvent-free because it usually affects the viscosity of the grease. However, even when it is obtained by solution polymerization, the solvent should be removed. There is no problem at all.

The molecular weight of the fluorocopolymer thus obtained is determined by gel permeation chromatography (G
The weight average molecular weight of 1000 or more in terms of polystyrene by PC) is preferable, and among them, 1,000 to 1,000,
It preferably has a weight average molecular weight of 000.
Furthermore, in order to easily disperse in grease and quickly orientate when applied to the substrate to prevent base oil diffusion,
A low degree of polymerization having a weight average molecular weight of 0 to 30,000 is preferred.

As the grease used in the present invention, a conventionally known grease may be used as it is without any particular limitation. For example, the thickener may be a soap type (metal soap type, complex soap type, etc.) or urea type. Any type may be used, and examples of the base oil include synthetic lubricating oils such as poly α-olefin oil, ethylene α-olefin cooligomer oil, silicone oil and diester oil.

The oil non-diffusion additive of the present invention is added completely in an amount of 0.01 to 15 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the above-mentioned grease component, so that the total amount of the base component in the grease can be improved. Oil diffusivity can be prevented.

The grease to which the oil non-diffusion additive according to the present invention is added has a negative effect such as erosion on metals, plastics and the like (for example, ABS, polycarbonate, nylon, polypropylene, polyethylene and polyacetal). Absent.

[0043]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited to the following examples.

Example 1 In this example, a typical method for producing the copolymer of the present invention is described by using a perfluoroalkyl group-containing ethylenically unsaturated monomer (A) and a polyoxypropylene group-containing ethylenically unsaturated monomer. A specific example of the binary copolymer of the saturated monomer (B) will be described.

C in a glass reaction vessel (internal volume: 500 ml)
₈ F ₁₇ CH ₂ CH ₂ OCOCH = CH ₂ (A-1) 55 g, polyoxypropylene group-containing ethylenically unsaturated monomer [oxypropylene group repeating unit number: 5 (B-2)] 12 g, methyl meta Acrylate (C-1) 1.2 g, 2-ethylhexyl acrylate (C-6) 0.8 g, ethyl acetate 3
19 g was added and the temperature was raised to 50 ° C. with stirring under a nitrogen atmosphere to homogenize the system. Next, lauryl mercaptan 1
0.4 g and 1.38 g of azobisisobutyronitrile are added, the temperature is raised to 70 ° C. for 30 minutes, and a copolymerization reaction is carried out at the same temperature for 8 hours. The nonvolatile content of the obtained copolymer was 20.1% by weight. After confirming that the nonvolatile content matches the theoretical value, the solvent was removed to a nonvolatile content of 99% or more to obtain a fluorine-based copolymer.

The polystyrene reduced molecular weight of this copolymer by gel permeation chromatography was Mw = 39.
It was 00. (This copolymer is referred to as Copolymer 1.) Hereinafter, using predetermined amounts of the monomers shown in Table 1 and Table 2,
By the same operation as above, the amount of the initiator and / or the amount of lauryl mercaptan was changed to obtain each copolymer.
The results of measuring the molecular weight of these polymers are shown in Table 1. These copolymers were used as additives for oil non-diffusion.

A test for the base oil diffusion preventing effect of the additive for non-oil diffusion according to the present invention was conducted by the following method. First, the test method will be described with reference to FIG. First, grease 1
Is coated on a ground glass plate (100 mm × 100 mm) so as to form a cylindrical shape having a diameter of 10 mm and a height of 0.2 mm. Then, it was put in a thermostat and an accelerated test was conducted under the condition of 60 ° C, and the diffusion state of the base oil after 24, 48, 72, and 96 hours was measured by using the part where the rough surface of the ground glass plate became translucent Evaluate as. In the marking method, the initial coating state is 10 mm. That is, the diffusivity when the base oil does not diffuse at all is 10 mm, and in the case where the base oil diffuses, the diameter including the grease initially applied is designated. In this embodiment, 10
2 parts by weight of Copolymer 1 was added to 0 part by weight of grease, and the mixture was uniformly mixed. The grease used here was a poly-α-olefin oil having a viscosity of 30 centistokes at 40 ° C. as a base oil and a consistency of 300 using lithium soap as a thickener.

[0048]

[Table 1]

Examples 2 to 12 Copolymer 2 obtained by copolymerizing the monomers shown in Table 1
The effect of preventing base oil diffusion was confirmed in the same manner as in Example 1 except that the components 1 to 12 were added to the grease instead of the copolymer 1.

Example 13 The effect of preventing base oil diffusion was confirmed in the same manner as in Example 1 except that 1 part by weight of copolymer 1 was added to 100 parts by weight of grease.

Example 14 The effect of preventing base oil diffusion was confirmed in the same manner as in Example 1 except that 5 parts by weight of copolymer 1 was added to 100 parts by weight of grease.

Comparative Example 1 Example 1 except that Copolymer 1 was not added to the grease
The effect of preventing base oil diffusion was confirmed in the same manner as.

Comparative Example 2 The same procedure as in Example 1 was repeated except that a fluorosurfactant having a perfluorocarbon chain as a hydrophobic group and oxyethylene as a hydrophilic group was added in place of the copolymer 1. The effect of preventing base oil diffusion was confirmed.

Table 2 shows the test results of Examples 1 to 10 and Comparative Examples 1 and 2.

[0055]

[Table 2]

The unit of numerical values in the table is mm.

[0057]

By adding the oil non-diffusion additive of the present invention to the grease, it is required for the grease to be used in various miniaturized mechanism parts, motors, various bearings, contacts, switches and the like. It is possible to prevent the low viscosity base oil made of synthetic lubricating oil used to satisfy the performances such as heat resistance, low temperature stability, and light torque property from diffusing (leaching) from the coated surface, and However, it does not adversely affect the base material such as plastic, and can eventually eliminate the fatal damage to the product such as defective operation and defective conductivity.

[Brief description of drawings]

FIG. 1 is a schematic view of a base oil diffusion prevention effect test of an oil non-diffusion additive.

[Explanation of code] Grease frosted glass Diffusion part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C10N 50:10

Claims (7)

[Claims] 1. An oil non-diffusion additive comprising a fluorine-based copolymer having a perfluoroalkyl group and a polyoxypropylene unit. 2. A fluorocopolymer is obtained by polymerizing a perfluoroalkyl group-containing ethylenically unsaturated monomer (A) and a polyoxypropylene unit-containing ethylenically unsaturated monomer (B) as essential components. An additive for non-diffusion of oil, which is obtained by 3. The carbon number of the perfluoroalkyl group is 3 to.
21. The oil non-diffusion additive according to claim 1 or 2, which is 21. 4. The additive for non-oil diffusion according to claim 1, wherein the number of repeating units of polyoxypropylene unit is 1 to 10. 5. A fluorine-based copolymer is further used as a monomer (B).
A non-fluorine-containing alkyl group-containing ethylenically unsaturated monomer (C) other than the above is polymerized.
The additive for non-oil diffusion according to any one of 1. 6. The additive for non-diffusion of oil according to claim 1, wherein the fluorine-based copolymer has a molecular weight of 1,000 to 30,000 in terms of polystyrene in terms of weight average molecular weight. 7. The composition according to claim 1, wherein the monomer (B) is used in an amount of 5 to 200 parts by weight based on 100 parts by weight of the monomer (A). Oil non-diffusion additive.