JP5450934B2 - Grease composition - Google Patents

Description

  The present invention relates to a grease composition, and more specifically, a grease capable of realizing low torque for improving energy efficiency and extending the life of a sliding component at a sliding portion between rubber members or between a rubber member and a resin member. Relates to the composition.

  Conventionally, grease has been used as a lubricant composition for gears and sliding parts, but gears (gears, etc.) have been developed for the purpose of reducing weight and cost in recent automobile parts, home appliances, OA equipment, and the like. In addition, resin members are increasingly used for sliding parts.

  Further, although a rubber member is used as a seal member in the vicinity of the resin member, such a rubber member is not in direct contact with the resin gear in a conventional large gear unit.

  However, in recent years, as a result of progress in downsizing for the purpose of reducing the weight and cost of the gear unit, the rubber member is in direct contact with the resin member and has to slide, and the rubber member is in contact with the resin member. When sliding, the dynamic friction coefficient becomes higher than expected at the sliding portion, and not only the sliding torque increases, but also a new problem occurs that the rubber member is worn.

  Such a problem is a new problem caused by downsizing of the gear unit. In order to solve such a new problem, if an oil-based agent is added to the grease composition more than necessary in order to reduce the friction coefficient, the grease composition may become soft and bleed out from the filled portion.

Patent Documents 1-4 disclose a grease composition used for sliding portions between a resin member and a metal member or between a metal member and a metal member.
Japanese Patent No. 2962561 JP-A 61-12791 JP 2006-0899575 A JP 2004-188607 A JP 2006-23291 A: A grease composition containing 10% by weight or more of MCA and used at a high temperature.

  However, the grease composition described in Patent Documents 1-4 is a grease composition used for sliding portions between a resin member and a metal member or between a metal member and a metal member, and sliding between rubber members or between a rubber member and a resin member. No issues have been disclosed regarding lowering the torque for improving energy efficiency at the location and extending the life of the sliding parts, and disclosure of the low dynamic friction coefficient in sliding between rubber members or between a rubber member and a resin member is also disclosed. Absent.

  Accordingly, an object of the present invention is to provide a grease composition capable of realizing a low torque for improving energy efficiency and a long life of a sliding component at a sliding portion between rubber members or between a rubber member and a resin member. There is to do.

  Other problems of the present invention will become clear from the following description.

  The above problems are solved by the following inventions.

(Claim 1)
Poly -α- olefin, ethylene -α- olefin copolymer, polybutene, alkylbenzene, and at least one or more mixtures synthetic hydrocarbon oil or Ranaru base oil consisting of selected from alkyl naphthalene,
A thickener made of lithium soap ;
A solid lubricant composed of melamine cyanurate (MCA);
A grease composition comprising:
81.8-90.9 wt% of the base oil , 6.1-8.1 wt% of the thickener, and the solid lubricant based on the total amount of the base oil , the thickener, and the solid lubricant 1.0 to 12.1 wt% of the agent ,
Dynamic friction coefficient according the following measuring methods, the 0.01 to 0.20 Der Heidelberg lease compositions,
A grease composition characterized by being used in sliding portions between rubber members or between a rubber member and a resin member .
(Measuring method of dynamic friction coefficient)
Using a reciprocating tester, apply the grease composition onto the NBR sheet (lower test piece) to a coating amount of 0.05 g, and apply a resin ball (upper test piece, diameter 10 mm) from above to a test load of 0 g. Press at 5 kgf and reciprocate at a sliding speed of 4 mm / sec (sliding distance 10 mm, test temperature: 70 ° C.). The friction coefficient was measured from the friction force generated between the upper and lower test pieces when reciprocatingly slid.

(Claim 2)
The grease composition according to claim 1, wherein the coefficient of dynamic friction is 0.05 to 0.15.

  According to the present invention, it is possible to provide a grease composition capable of realizing a low torque for improving energy efficiency and a long life of a sliding component at a sliding portion between rubber members or between a rubber member and a resin member. it can.

  Embodiments of the present invention will be described below.

  The grease composition used in the present invention comprises a base oil, a thickener, and a solid lubricant, and is used in sliding portions between rubber members or between a rubber member and a resin member, and has a low dynamic friction coefficient. To do.

  As the base oil used in the present invention, it is preferable to use at least one or more synthetic oils selected from synthetic hydrocarbon oils, ester synthetic oils, ether synthetic oils, glycol synthetic oils, and fluorine oils. .

As the synthetic hydrocarbon oil, for example, at least one or a mixture of two or more selected from poly-α-olefin, ethylene-α-olefin copolymer, polybutene, alkylbenzene, alkylnaphthalene and the like can be used.

  As the ester-based synthetic oil, for example, at least one kind or a mixture of two or more kinds selected from ester oils such as diesters, polyol esters, and aromatic esters can be used.

  As the ether synthetic oil, at least one kind or a mixture of two or more kinds selected from alkyl diphenyl ether and the like can be used.

  As the glycol-based synthetic oil, at least one kind or a mixture of two or more kinds selected from polyethylene glycol, polypropylene glycol and the like can be used.

  As the fluorine oil, at least one or a mixture of two or more selected from perfluoropolyether oils represented by the following general formulas (1), (2), and (3) can be used.

RfO [CF (CF ₃ ) CF ₂ O] _a (CF ₂ O) _b Rf (1)

In the formula (1), Rf is a perfluoro lower alkyl group, a and b are natural numbers, a + b = 3 to 200, and b may be 0. a: b = 100: 0 to 50:50, and the CF (CF ₃ ) CF ₂ O group and the CF ₂ O group are randomly bonded in the main chain.

RfO (CF ₂ CF ₂ O) _m (CF ₂ O) _n Rf (2)

In the formula (2), Rf is a perfluoro lower alkyl group, m and n are natural numbers, m + n = 3 to 200, m: n = 10 to 90:90 to 10, and a CF ₂ CF ₂ O group And CF ₂ O groups are randomly bonded in the main chain.

F (CF ₂ CF ₂ Cf ₂ O) _m CF ₂ CF ₃ (3)

  In formula (3), m is an integer of 2-100.

  In the general formulas (1), (2), and (3), the perfluoro lower alkyl group has 1 to 5 carbon atoms, preferably 1 to 5 carbon atoms such as a perfluoromethyl group, a perfluoroethyl group, and a perfluoropropyl group. 3 perfluoro lower alkyl groups.

  The base oil used in the present invention is more preferably a synthetic hydrocarbon oil or fluorine oil in consideration of the effect on resin and rubber (resin and rubber do not deteriorate), and the effect on resin and rubber (resin and rubber do not deteriorate). In addition to the cost reduction, synthetic hydrocarbon oil is more preferable. Particularly preferred is poly-α-olefin (PAO).

  Examples of the thickener used in the present invention include metal soap and metal composite soap. Examples of the metal soap include Li soap, Ca soap and aluminum soap. In Li soap, 12-hydroxystearic acid and stearic acid are used. The thing using is mentioned. Examples of the metal composite soap include Li composite soap, Ca composite soap, Ba composite soap and the like.

  As the thickener used in the present invention, Li soap is preferable.

  When the melamine cyanurate (MCA) is used as the solid lubricant in the grease composition of the present invention, it is preferable for producing a lubricating grease composition having a low friction coefficient in sliding between the rubber member and the resin member.

  Melamine cyanurate (MCA) is blended in the range of 0.1 to 20 wt%, preferably in the range of 1 to 5 wt%, and more preferably in the range of 2 to 5 wt%.

  By mix | blending in the said range, the friction coefficient of the sliding location of rubber members or a rubber member and a resin member can be reduced. The friction coefficient is reduced by the MCA adsorbing to the rubber member.

  If the blending amount is less than 0.1 wt%, the MCA adsorption to the rubber member is small, so the friction coefficient cannot be reduced, and if the blending amount of MCA is 20 wt% or more, the grease composition itself becomes hard. There is a problem that the friction coefficient increases.

  The solid lubricant may be MCA alone, but may be used in combination with other solid lubricants such as polytetrafluoroethylene (PTFE), molybdenum disulfide, organic molybdenum, graphite, boron nitride, silane, etc. Is preferably used in combination with PTFE.

  To the grease composition of the present invention, an antioxidant, an extreme pressure agent, a rust inhibitor, a corrosion inhibitor, a viscosity index improver, an oily agent and the like are appropriately selected and added within a range not impairing the effects of the present invention. Can do.

  Examples of the antioxidant include phenols such as 2,6-di-t-butyl-4-methylphenol and 4,4′-methylenebis (2,6-di-t-butylphenol), and alkyldiphenylamines (alkyl groups). Are those having 4 to 20 carbon atoms), amine-based antioxidants such as triphenylamine, phenyl-α-naphthylamine, phenothiazine, alkylated phenyl-α-naphthylamine, phenothiazine, alkylated phenothiazine, etc. A mixture of seeds or more can be used.

  Examples of extreme pressure additives include phosphorous compounds such as acidic phosphate esters, phosphite esters, and acidic phosphate ester amine salts, sulfur compounds such as sulfides and disulfides, chlorinated paraffin, and chlorinated diphenyl. And organic metal compounds such as zinc dialkyldithiophosphate (ZnDTP) and molybdenum dialkyldithiocarbamate (MoDTP).

  Examples of the rust preventive include fatty acids, fatty acid soaps, alkyl sulfonates, fatty acid amines, oxidized paraffins, and polyoxyethylene alkyl ethers.

  Examples of the corrosion inhibitor include benzotriazole, benzimidazole, thiadiazole and the like.

  Examples of the viscosity index improver include polymethacrylate, ethylene-propylene copolymer, polyisobutylene, polyalkylstyrene, styrene-isoprene copolymer hydride, and the like.

  Examples of the oily agent include fatty acids, higher alcohols, polyhydric alcohols, polyhydric alcohol esters, aliphatic esters, aliphatic amines, fatty acid monoglycerides, and the like.

  As rubbers of rubber members to be lubricated using the grease composition of the present invention, nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), styrene butadiene rubber (SBR), silicone rubber (VMQ) Fluorine rubber (FKM), ethylene propylene rubber (EPDM), chloroprene rubber (CR), urethane rubber (U), butadiene rubber (BR), butyl rubber (IIR), isoprene rubber (IR) and the like.

  The resin of the resin member to be lubricated using the grease composition of the present invention includes polyethylene (PE), polypropylene (PP), ABS resin (ABS), polyacetal (POM), nylon (PA), polycarbonate <PC>, phenol Examples include resin (PF), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyether sulfone (PES), polyimide (PI), polyether ether ketone (PEEK), and the like.

  The grease composition of the present invention has physical properties such that the coefficient of dynamic friction is 0.01 to 0.20, preferably 0.05 to 0.15 at the sliding portion between the rubber members or between the rubber member and the resin member. It has the following physical properties.

  If the dynamic friction coefficient is outside the scope of the present invention, the problem of the present invention cannot be solved.

  The above dynamic friction coefficient is determined by applying a grease composition on an NBR sheet (lower test piece) to a coating amount of 0.05 g using a reciprocating test machine, and resin POM balls (upper test piece, diameter 10 mm) from above. ) With a test load of 0.5 kgf and reciprocating at a sliding speed of 4 mm / sec (sliding distance 10 mm, test temperature: 70 ° C.). The friction coefficient was measured from the friction force generated between the upper and lower test pieces when reciprocatingly slid.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited by this Example.

Example 1
<Blend ingredients and blending amounts>
(1) Base oil Poly-α-olefin
("DURASYN 166" manufactured by Iones Oligomers) 90% by weight (2) Thickener Li soap ("Li-OHST" manufactured by Katsuta Chemical Industries) 8% by weight (3) Solid lubricant MCA (manufactured by Nissan Chemical Industries, Ltd. MC-6000 ") 1 wt% (4) antioxidant
Phenylnaphthylamine (Ciba Specialty Chemicals)
"Irganox L06") 1% by weight

<Preparation of grease>
The above base oil and thickener were blended in a mixing and stirring kettle and heated and stirred. After heating and stirring to the melting temperature, cooling was performed. Various additives were added to the produced gel substance, stirred, and then passed through a roll mill to prepare a grease composition.

  About the obtained grease composition, the blending consistency and the dynamic friction coefficient were measured. The results are shown in Table 1.

<Measurement method>
(Consistency)
Test temperature: 25 ° C
Test method: Consistency was measured according to JIS K2220.

(Dynamic friction coefficient)
The lubricity of the lubricating grease composition was evaluated with a reciprocating motion tester. Grease is applied to the rubber sheet, and a resin ball is pressed from above to reciprocate. The friction coefficient was measured from the friction force generated between the resin ball and the rubber sheet when reciprocally slid.

Reciprocating motion tester Upper test piece: POM ball (diameter 10mm) (resin ball)
Lower test piece: NBR sheet (rubber sheet)
Test load: 0.5kgf
Grease application amount: 0.05g
Sliding speed: 4mm / sec
Test temperature: 70 ° C
Sliding distance: 10mm

Example 2-Example 3
Table 1 shows the results of evaluation in the same manner as in Example 1 except that the blending amount of the base oil, the blending amount of the thickener, and the blending amount of the solid lubricant MCA are changed as shown in Table 1. .

Example 4
Table 1 shows the results of evaluation in the same manner as in Example 1 except that the blending amount of the base oil and the blending amounts of MCA and PTFE, which are solid lubricants, were changed as shown in Table 1.

Example 5
Table 1 shows the results of evaluation in the same manner as in Example 1 except that the blending amount of the base oil, the blending amount of the thickener, and the blending amounts of MCA and PTFE, which are solid lubricants, were changed as shown in Table 1. Shown in

Comparative Example 1 and Comparative Example 4
Table 1 shows the results of evaluation in the same manner as in Example 1 except that the blending amount of the base oil and the blending amount of MCA as the solid lubricant were changed as shown in Table 1.

Comparative Example 2 and Comparative Example 3
Table 1 shows the results of evaluation in the same manner as in Example 1 except that the blending amount of the base oil and the blending amounts of MCA and PTFE, which are solid lubricants, were changed as shown in Table 1.

Claims (2)

Poly -α- olefin, ethylene -α- olefin copolymer, polybutene, alkylbenzene, and at least one or more mixtures synthetic hydrocarbon oil or Ranaru base oil consisting of selected from alkyl naphthalene,
A thickener made of lithium soap ;
A solid lubricant composed of melamine cyanurate (MCA);
A grease composition comprising:
81.8-90.9 wt% of the base oil , 6.1-8.1 wt% of the thickener, and the solid lubricant based on the total amount of the base oil , the thickener, and the solid lubricant 1.0 to 12.1 wt% of the agent ,
Dynamic friction coefficient according the following measuring methods, the 0.01 to 0.20 Der Heidelberg lease compositions,
A grease composition characterized by being used in sliding portions between rubber members or between a rubber member and a resin member .
(Measuring method of dynamic friction coefficient)
Using a reciprocating tester, apply the grease composition onto the NBR sheet (lower test piece) to a coating amount of 0.05 g, and apply a resin ball (upper test piece, diameter 10 mm) from above to a test load of 0 g. Press at 5 kgf and reciprocate at a sliding speed of 4 mm / sec (sliding distance 10 mm, test temperature: 70 ° C.). The friction coefficient was measured from the friction force generated between the upper and lower test pieces when reciprocatingly slid.   The grease composition according to claim 1, wherein the coefficient of dynamic friction is 0.05 to 0.15.