JP2008297367A - Foamed solid lubricant and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foamed solid lubricant which can also be used at a place on which external stress such as compression or bending acts and where the employment of a solid lubricant has been difficult conventionally, and to provide a method for producing the same. <P>SOLUTION: This foamed solid lubricant produced by foaming and curing a mixture of a lubricating component, a urethane prepolymer having isocyanate groups in the molecule, a curing agent, and a foaming agent is characterized in that the lubricating component is at least one lubricating component selected from lubricants and greases; the urethane prepolymer has an isocyanate group content of ≥2 wt.% to <6 wt%; the foaming agent is water; the lubricating component is contained in an amount of 30 to 70 wt.% based on the total amount of the mixture; and an open cell rate is ≥50% after foamed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a foamed solid lubricant and a method for producing the same.

In automobiles and industrial machinery, it is necessary to supply lubricating oil or grease to lubricated parts such as rotating parts and sliding parts, but depending on the operating conditions such as the temperature at which the lubricating oil or grease is used, the lubricant may scatter from the lubricated parts. Or there is a problem of dripping. Therefore, in an environment where it is difficult to use lubricating oil or grease, solid lubricants are often used for bearings. There have been reported cases in which such a lubricant is sealed in a bearing, solidified, and used to improve the bearing life (see Patent Documents 1 to 3).
Also known is a self-lubricating polyurethane elastomer obtained by reacting a polyurethane raw material polyol and diisocyanate in a lubricating component (see Patent Document 4).
Such a solid lubricant gradually exudes lubricating oil when it is sealed in a bearing and solidified. If this is used, maintenance for replenishing the lubricating oil becomes unnecessary, and there is a lot of moisture. In many cases, it is useful for extending the life of the bearing even in environments where it is used or where there is a strong inertia.
However, when such a lubricant composition is used for a portion where external stress such as compression and bending is repeatedly applied at a high frequency, such as a drive unit of a constant velocity joint, deformation is difficult. Therefore, it is difficult to use because it requires a very large driving force or may be damaged or broken as a result of applying a very large stress to the solid lubricant. There is a demand for the development of solid lubricants that can be used in such places. However, since the strength and the filling rate of the solid lubricant are usually contradictory, it is difficult to maintain the lubricant at a high filling rate, and there is a possibility that the extension of the service life may be hindered.

One of the methods for imparting high flexibility to a solid lubricant is foaming of a solid component. By foaming the solid component, the apparent elastic force against the external stress is improved, and the material allows deformation. There has been reported an example in which such a lubricant-containing foam is used for an inner / outer ring assembly such as a bearing or a constant velocity joint (see Patent Document 5).
In the lubricant disclosed in Patent Document 5, the solid lubricant is compressed following the boot that is deformed by the bending of the joint. Therefore, the liquid lubricant that has oozed out of the solid lubricant is supplied to the necessary part, and good lubrication is possible. The lubricant containing method reported here is a post-impregnation type in which a prefoamed resin is impregnated with a lubricating oil. In the case of the post-impregnation type, since the lubricating oil is not contained in the solid component, there is a problem that the lubricating oil retention force is small, and the lubricating oil comes out at a time when used under high speed conditions. Such foamed lubricants can be used in a short period of lubrication or in an enclosed space, but if used in a long period of lubrication or in an open space, the supply of lubricating oil becomes insufficient and cannot be used.
Further, since the oil retention is not high, the lubricant constantly flows in the space while repeating the release of the lubricating oil and the absorption into the foam. In such a case, depending on the chemical properties of the lubricant and the additives contained therein, there is a possibility that the boot material may be attacked and deteriorated, and there is a problem that the material selection of either the lubricant or the boot material is limited. is there. In addition, there are problems in that the number of man-hours in the manufacturing process associated with post-impregnation, the increase in manufacturing time, and the cost increase associated therewith are unavoidable.

On the other hand, a lubricating composition in which a lubricating oil is contained in a polyurethane resin produced from a polyol component and an isocyanate component is known (see Patent Documents 6 to 8).
In addition, a hydroxyl-terminated polydiene compound has been reported as a raw material that can be oil-extended by bitumen or the like (see Patent Document 9).
However, there is no known solid foamed lubricant that has rubber elasticity that can be used at sites where external stress such as compression and bending acts, has high lubricant retention, and allows large deformation.
JP-A-6-41569 JP-A-6-172770 JP 2000-319681 A JP-A-11-286601 Japanese Patent Laid-Open No. 9-42297 JP-A-60-173010 Japanese Patent Laid-Open No. 62-241997 JP-A-8-3259 JP 58-189243 A

  The present invention has been made in order to cope with such problems, and is a foamed solid lubricant that can be used even in places where external stress such as compression / bending, where it has been difficult to use solid lubricants in the past. And it aims at provision of the manufacturing method.

Even in places where external stress such as compression and bending acts, research on foamed solid lubricants that have high lubricant retention and allow large deformations is not sufficient. It has been found that it is sufficient, and it is necessary to include a lubricating oil or the like in the solid resin component to increase the lubricant retention. A large amount of deformation can be allowed, and by increasing the lubricant holding power, it is possible to supply a necessary amount to a necessary portion as compared with grease lubrication that is widely used in industry. The present invention has been made based on such findings. That is, the foamed solid lubricant of the present invention is a foamed solid lubricant obtained by foaming and curing a mixture containing a lubricating component, a urethane prepolymer having an isocyanate group in the molecule, a curing agent, and a foaming agent. The lubricating component is at least one lubricating component selected from lubricating oils and greases, the urethane prepolymer has an isocyanate group content of 2% by weight or more and less than 6% by weight, the foaming agent is water, The mixture is characterized by containing 30 to 70% by weight of the lubricating component with respect to the whole mixture and having an open cell ratio after foaming of 50% or more.
The urethane prepolymer having an isocyanate group in the molecule is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer.

In the foamed solid lubricant, the ratio of the isocyanate group contained in the urethane prepolymer and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of curing agent / NCO) = 1 / (1.1- 2.5).
Further, the ratio of the hydroxyl group of water as a blowing agent and the functional group of the curing agent is an equivalent ratio (water hydroxyl group / functional group of the curing agent) = 1 / (0.7 to 2.0). And

In the foamed solid lubricant, the curing agent is an aromatic polyamino compound. In particular, the aromatic polyamino compound is an aromatic polyamino compound having a substituent at the position adjacent to the amino group.
In the foamed solid lubricant, the mixture containing the lubricating component, the urethane prepolymer, the curing agent, and the foaming agent is filled with the periphery of the sliding member or in the molding die. It is characterized by being cured.

  The method for producing a foamed solid lubricant of the present invention includes a mixing step of obtaining a mixture by mixing a lubricating component, a urethane prepolymer having an isocyanate group in the molecule, a curing agent, and a foaming agent, Before the foaming / curing of the mixture is completed, a filling step of filling the mixture into the periphery of the sliding member or in a mold, and a foaming / curing step of foaming / curing the filled mixture are performed. It is characterized by providing.

The foamed solid lubricant of the present invention is obtained by foaming and curing a mixture for producing a foamed solid lubricant comprising a lubricating component, a urethane prepolymer having an isocyanate group in the molecule, a curing agent, and a foaming agent. Therefore, the lubricating component is held in the foamed / cured solid component. By foaming this solid component, free deformation with respect to external stress is possible, and in particular, flexibility can be improved. This lubricating component is mainly present in the solid component, and the lubricating component can be gradually released to the required site by external factors such as compression, bending, twisting, and expansion.
The foamed solid lubricant is foamed and hardened by filling the mixture around the sliding part or rolling part or in the molding die, so there is no need for post-processing such as cutting. Excellent holding power.
As a result of the above, by using the solid foamed lubricant of the present invention for constant velocity joints, it is possible to reduce costs by reducing the amount of conventional grease, reduce the load on boot materials, and reduce the weight and size of constant velocity joints. The technology is highly socially important not only from economically advantageous industrial aspects, but also from a plurality of viewpoints, such as environmental load reduction and design freedom.

  Moreover, since the manufacturing method of a foaming solid lubricant is provided with the said mixing process, a filling process, and a foaming / curing process, it is possible to directly produce a foaming solid lubricant that is a foamed / cured product holding a lubricant. And there is no need for post-processing such as cutting or post-impregnation. As a result, the production efficiency is improved and it can be manufactured at a low cost.

As the solid component used in the foamed solid lubricant of the present invention, it is preferable to use a urethane prepolymer that is excellent in heat resistance and flexibility and can be reduced in cost.
The foamed solid lubricant of the present invention is a foamed solid lubricant in which the urethane prepolymer is foamed and cured to be porous, and a lubricating component is occluded inside the resin. It should be noted that the lubrication component is occluded in the foamed / cured solid component is a urethane prepolymer or a curing agent in the solid component obtained by foaming / curing a liquid / semi-solid lubricant component such as a lubricating oil or grease described later. It does not react with, and does not become a compound. This foamed solid lubricant is excellent in lubricant retention, and can be produced at a low cost while suppressing the amount of lubricating oil oozing out even if it is deformed by an external force.

The urethane prepolymer that can be used in the present invention is obtained by a reaction between a compound having an active hydrogen group and a polyisocyanate, and the isocyanate group is contained at the end of the molecular chain or at the end of the side chain branched from within the molecular chain. It may be. The urethane prepolymer may have a urethane bond in the molecular chain.
Depending on the type of monomer (= compound having an active hydrogen group) to be reacted, it is classified into caprolactone, ester and ether. There are Takenate L-1170 (manufactured by Mitsui Chemicals Polyurethanes), L-1158 (manufactured by Mitsui Chemicals Polyurethanes), and Coronate 4090 (manufactured by Nippon Polyurethanes) as ethers. Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.) is used as the ester system, and Takenate L-1350 (manufactured by Mitsui Chemical Polyurethane Co., Ltd.), Takenate L-1680 (manufactured by Mitsui Chemical Polyurethane Co., Ltd.), and Sianaprene 7-QM are used as the caprolactone system. (Manufactured by Mitsui Chemicals Polyurethane), Plaxel EP1130 (manufactured by Daicel Chemical Industries) and the like.
In addition, oligomers or prepolymer compounds whose terminal groups are modified to isocyanate groups can also be used. Examples of such a compound include a terminal isocyanate-modified polyether polyol and an isocyanate-modified product of a hydroxyl group-terminated polybutadiene. Examples of the terminal isocyanate-modified polyether polyol include Coronate 1050 (manufactured by Nippon Polyurethane Co., Ltd.). Moreover, poly-bd MC50 (manufactured by Idemitsu Kosan Co., Ltd.) and poly-bd HTP9 (manufactured by Idemitsu Kosan Co., Ltd.) can be mentioned as isocyanate-modified products of hydroxyl-terminated polybutadiene.
These urethane prepolymers can be used in combination of two or more depending on the desired mechanical properties.

In the present invention, a urethane prepolymer having an isocyanate group content of 2 wt% or more and less than 6 wt% can be used. If the isocyanate group (NCO) content is less than 2% by weight, it will be difficult to achieve both foamability and elasticity, and if it is more than 6% by weight, the hardness will be too high and the impact resilience will increase and deformation due to external force will occur. It becomes easy to generate heat when receiving.
Moreover, the isocyanate group can use the block isocyanate etc. which blocked the isocyanate group with blocking agents, such as phenols, lactams, alcohols, and oximes.

The curing agent for curing the urethane prepolymer is preferably a compound having active hydrogen, and examples thereof include a polyamino compound having a functional group as an amino group and a polyol compound having a functional group as a hydroxyl group.
Polyamino compounds include 3,3'-dichloro-4,4'-diaminodiphenylmethane (hereinafter referred to as MOCA), 3,3'-dimethyl-4,4'-diaminodiphenylmethane, and 3,3'-dimethoxy-4. , 4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, trimethylene-bis- (4-aminobenzoate), bis (methylthio) -2,4- Aromatics typified by toluenediamine, bis (methylthio) -2,6-toluenediamine, methylthiotoluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine Examples include polyamino compounds.

  Among the polyamino compounds, aromatic amino compounds are preferable because of low cost and excellent physical properties, and aromatic diamino compounds having a substituent at the position adjacent to the amino group are particularly preferable. In the present invention, it is considered that the reactivity of the amino group is suppressed by the substituent at the adjacent position because it undergoes a step of curing together with foaming.

  When the urethane prepolymer is cured with a polyamino compound, it becomes a foamed solid lubricant having urethane and urea bonds in the molecule. By generating urea bonds, the urethane bond density in the molecule is lowered, and elongation and impact resilience are improved. Moreover, rigidity can be provided by generating a urea bond.

  Examples of the polyol compound include low molecular polyols such as 1,4-butane glycol and trimethylolpropane, polyether polyols, castor oil polyols, and polyester polyols. Of the polyol compounds, trimethylolpropane is preferred.

The ratio of the isocyanate group (—NCO) contained in the urethane prepolymer and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio when the functional group is an amino group or a hydroxyl group (functional group of the curing agent). /NCO)=1/(1.1 to 2.5).
The ratio of the isocyanate group contained in the urethane prepolymer, the amino group (—NH ₂ ) or hydroxyl group (—OH) of the curing agent, and the hydroxyl group of water (—OH) as the foaming agent, Flexibility, elasticity, etc. are determined. When the amino group (—NH ₂ ) or hydroxyl group (—OH) of the curing agent is reacted with the isocyanate group (—NCO) of the urethane prepolymer in an equivalent amount, an isocyanate group (—NCO) that reacts with water as the foaming agent is formed. Since it will disappear, the range of (functional group of curing agent / NCO) = 1 / (1.1 to 2.5) is preferable. Moreover, the ratio of the hydroxyl group of water which is a foaming agent and the functional group of a hardening | curing agent is the range of (hydroxyl group of water / functional group of a hardening | curing agent) = 1 / (0.7-2.0) by an equivalent ratio.
If the amount of the curing agent is less than the above range, not only the physical properties such as the strength of the foamed solid lubricant are remarkably lowered, but also the urethane elastomer may not be cured.

The lubricating component that can be used in the present invention can be used as long as it does not dissolve the solid component forming the foam. As the lubricating component, for example, lubricating oil, grease, wax or the like can be used alone or in combination. Particularly preferred are hydrocarbon-based lubricants, hydrocarbon-based greases, or mixtures of hydrocarbon-based lubricants and hydrocarbon-based greases.
Examples of the hydrocarbon-based lubricating oil include paraffinic and naphthenic mineral oils, hydrocarbon-based synthetic oils, GTL base oils, and the like. These can be used alone or as a mixed oil. In addition, ester synthetic oils, ether synthetic oils, fluorine oils, silicone oils and the like can also be used. These can be used alone or as a mixed oil.
The hydrocarbon-based grease is a grease having a hydrocarbon oil as a base oil, and examples of the base oil include the above-described hydrocarbon-based lubricating oil. Examples of the thickener include lithium soaps, lithium complex soaps, calcium soaps, calcium complex soaps, aluminum soaps, aluminum complex soaps, and other urea compounds such as diurea compounds and polyurea compounds. It is not a thing. The diurea compound is obtained by the reaction of diisocyanate and monoamine, and the polyurea compound is obtained by the reaction of diisocyanate and polyamine. In addition, greases based on ester-based synthetic oils, ether-based synthetic oils, GTL base oils, fluorine oils, silicone oils and the like can also be used.

  As the lubricating component, hydrocarbon synthetic wax, polyethylene wax, higher fatty acid ester wax, higher fatty acid amide wax, ketone / amines, hydrogenated oil, and the like can be mixed and used.

Since the means for foaming the foamed solid lubricant of the present invention uses an isocyanate compound as a raw material, it is preferable to use water that reacts with the isocyanate compound to generate carbon dioxide gas.
Moreover, it is preferable to use a catalyst as needed, for example, a tertiary amine catalyst or an organometallic catalyst is used. Examples of the tertiary amine catalyst include monoamines, diamines, triamines, cyclic amines, alcohol amines, ether amines, imidazole derivatives, and acid block amine catalysts.
Examples of organometallic catalysts include stanaoctate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin maleate, dioctyltin dimercaptide, dioctyltin thiocarboxylate, octenoate, etc. Is mentioned. Moreover, you may mix and use these multiple types for the purpose of adjusting the balance of reaction.

The foamed solid lubricant of the present invention is obtained by foaming and curing a mixture containing the above-mentioned lubricating component, urethane prepolymer, curing agent, and foaming agent.
The blending ratio of the lubricating component is 30% to 70% by weight, preferably 40% to 60% by weight, based on the entire mixture. If the lubricating component is less than 30% by weight, the supply amount of lubricating oil or the like is so small that it cannot function as a foamed solid lubricant, and if it exceeds 70% by weight, it may not solidify.

  In the present invention, the open cell ratio of the foamed solid lubricant after foaming is 50% or more, preferably 50% or more and 90% or less. When the open cell ratio is less than 50%, the ratio of the resin component (solid component) lubricating oil temporarily taken up into the closed cells increases and may not be supplied to the outside when necessary. If it exceeds 90%, it may be disadvantageous for long-term use due to a decrease in the oil retention of the lubricant and an increase in the amount of lubricant released, or the strength (durability) of the foamed solid lubricant itself may decrease. I get out.

The open cell ratio of the foamed solid lubricant of the present invention can be calculated by the following procedure.
(1) The foamed solid lubricant that has been foam-cured is cut into an appropriate size to obtain sample A. The weight of sample A is measured.
(2) A is soxhlet washed (solvent: petroleum benzine) for 3 hours. Thereafter, the sample is left in a thermostatic bath at 80 ° C. for 2 hours to completely dry the organic solvent, and sample B is obtained. The weight of sample B is measured.
(3) The open cell ratio is calculated by the following procedure.
Open cell ratio = (1− (weight of resin component of sample B−weight of resin component of sample A) / weight of lubricating component of sample A) × 100
The resin component weight and the lubrication component weight of Samples A and B are calculated by multiplying the weights of Samples A and B by the composition charge ratio.
Lubricating components taken into discontinuous closed cells are not released to the outside by Soxhlet cleaning for 3 hours, so the weight of sample B is not reduced. The open cell ratio can be calculated as a result of the release of the lubricating component.

In the present invention, various additives such as pigments, antistatic agents, flame retardants, antifungal agents and fillers can be added to the foamed solid lubricant as necessary.
In addition, solid lubricants such as molybdenum disulfide and graphite, friction modifiers such as organic molybdenum, oily agents such as amines, fatty acids, and fats, antioxidants such as amines and phenols, petroleum sulfonates, dinonylnaphthalene sulfone Antirust agents such as nates and sorbitan esters, extreme pressure agents such as sulfur and sulfur-phosphorus, antiwear agents such as organic zinc and phosphorus, metal deactivators such as benzotriazole and sodium nitrite, polymethacrylate, polystyrene Various additives such as a viscosity index improver such as

In the present invention, using a reactive impregnation method in which a foaming reaction and a curing reaction are simultaneously performed in the presence of a lubricating component such as a lubricating oil, in order to simultaneously achieve a high filling of the lubricating component and a high elongation of material properties at the same time. desirable. This is because the lubricant is uniformly impregnated into the foam formed in the foam during the foam formation stage, and the lubricant is occluded in the foamed / cured solid component, so that the lubricant is highly filled and the material properties It is considered that the high elongation of both is compatible.
On the other hand, after the foam is manufactured in advance, the post-impregnation method in which the lubricant is impregnated does not have sufficient lubricant holding power, and the lubricant is released in a short period of time and supplied when used for a long time. It becomes insufficient.

The method for producing a foamed solid lubricant of the present invention includes a mixing step of obtaining a mixture by mixing a lubricating component, a urethane prepolymer having an isocyanate group in the molecule, a curing agent, and a foaming agent, Before the foaming / curing of the mixture is completed, a filling step of filling the mixture around the sliding member or in a mold and a foaming / curing step of foaming / curing the filled mixture are provided. .
In the mixing step, the method of mixing the urethane prepolymer, the curing agent, the lubricating component, and the foaming agent is not particularly limited, and a commonly used agitator such as a Henschel mixer, a ribbon mixer, a juicer mixer, or the like. Can be mixed using.
Since the mixture is quickly cured by the curing agent and the foaming agent, it is desirable to add the other components except the curing agent and the foaming agent to the stirrer and finally the curing agent and the foaming agent.

  In the filling step, the mixture containing the urethane prepolymer, the curing agent, the lubricating component, and the foaming agent is filled around the sliding member or in the molding die before the foaming and curing of the mixture is completed. Foaming of a urethane prepolymer using a carbon dioxide produced by a chemical reaction between isocyanate and water in a mixture filled in a molding die around a sliding member, and a urethane prepolymer in the mixture The curing reaction with the curing agent proceeds at the same time, and a foam, which is a foamed / cured product having the shape of the filling space, is formed around the sliding member or in the molding die. The foam impregnated with this lubricating component is the foamed solid lubricant of the present invention.

  In the above production method, it is desirable to use a surfactant such as a commercially available silicone foam stabilizer and to uniformly disperse each raw material molecule. Further, the surface tension can be controlled by the type of the foam stabilizer, and the type of the generated bubbles can be controlled to open cells or closed cells. Examples of such surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, and fluorine surfactants.

  In addition, as the equipment having the sliding member in the above manufacturing method, there are a bearing, a constant velocity joint, a ball screw, a linear guide, a spherical bush, and the like. And a mixture containing a curing agent and a foaming agent can be foamed and cured after filling to directly manufacture a device in which the foamed solid lubricant is enclosed.

Moreover, it can also shape | mold without using the apparatus (henceforth a shaping die etc.) which has a shaping die and a sliding member in the said manufacturing method. In this case, it is necessary to post-process the foamed / cured product into a desired shape by cutting or grinding. In addition, when a molding die is not used, the lubricating component is difficult to be retained in the foamed / cured product, so if the amount of lubricant is insufficient, it is necessary to post-impregnate the lubricant after post-processing to the desired shape There is. In addition, even if the cured foam is post-impregnated with a lubricant, the lubricant retention is reduced compared to a method using a molding die or the like, and the lubricant is likely to leak when handling the foam. Problems are likely to occur.
From the above, in the present invention, it is preferable to adopt a method of filling the mixture into a molding die or the like in terms of quality, work and cost.

  In the present invention, the lubricating component contained in the foamed solid lubricant in an impregnated state does not exude suddenly even when the foam is deformed by an external force, and the lubricating component can be efficiently exuded and used. . As a result, the amount of the lubricating component may be minimized, and the lubricating performance can be maintained for a long period.

Lubricating components, urethane prepolymers, curing agents, foaming agents, and catalysts used in Examples and Comparative Examples are shown below. In addition, () represents an abbreviation in the table.
Lubricating component Lubricating oil (lubricating oil 1): Turbine 100 (paraffinic mineral oil, manufactured by Nippon Oil Corporation)
Lubricating oil (lubricating oil 2): Crisef 150 (Naphthenic mineral oil, manufactured by Nippon Oil Corporation)
Lubricating oil (lubricating oil 3): Shin fluid 801 (poly-α-olefin, manufactured by Nippon Steel Chemical Co., Ltd.) Lubricating grease (grease): Pyronock Universal N6C (manufactured by Nippon Oil Corporation)
Urethane prepolymer Caprolactan-based urethane prepolymer 1 (prepolymer 1): Plaxel EP1130 (NCO 3.3%, manufactured by Daicel Chemical Industries)
Ether-based urethane prepolymer (Prepolymer 2): Coronate 4090 (NCO 4.3%, manufactured by Nippon Polyurethane Co., Ltd.)
Ester urethane prepolymer (Prepolymer 3): Coronate 4047 (NCO 4.3%, manufactured by Nippon Polyurethane Co., Ltd.)
Caprolactan urethane prepolymer (Prepolymer 4): Takenate L-1350 (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 5): Takenate L-1170 (NCO 2.4%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (prepolymer 6): Takenate L-1680 (NCO 3.2%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (Prepolymer 7): Cyanaprene 7-QM (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 8): Takenate L-1158 (NCO 4.4%, manufactured by Mitsui Chemicals Polyurethanes)
Hardener MOCA (MOCA): Iharacamine MT (manufactured by Ihara Chemical)
Trimethylene-bis- (4-aminobenzoate) (CUA-4): CUA-4 (manufactured by Ihara Chemical)
Mixture of bis (methylthio) -2,4-toluenediamine, bis (methylthio) -2,6-toluenediamine and methylthiotoluenediamine (Etacure 300): Etacure 300 (manufactured by Albemarle)
Trimethylolpropane: Reagent blowing agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (catalyst) DM70 (manufactured by Tosoh Corporation)

Examples 1-3, 6, 7, 9, 10, 12-17, 19-20, Comparative Examples 1-3
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 80 ° C., the raw materials excluding the curing agent, amine catalyst and foaming agent were mixed well at the blending ratios shown in Tables 1 to 3. Next, MOCA dissolved at 120 ° C. was put into a beaker and well stirred. Subsequently, an amine catalyst and a foaming agent (only Comparative Example 2 had no foaming agent) were added and stirred. After a few seconds, the foaming reaction started, and it was left to cure at 100 ° C. for 30 minutes to obtain a cylindrical specimen. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam in which oil oozes out when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Are also shown in Tables 1 to 3.
Further, the open cell ratio was measured by the above-described method, and the centrifugal oil separation evaluation was measured by the following method. The results are shown in Tables 1 to 3.
Centrifugal oil separation evaluation test Centrifugal oil separation was measured in order to examine the sustained release of the lubricant. Centrifugal oil separation showed the oil reduction rate relative to the oil filling amount when rotated for 1 hour under the conditions of a rotor radius of 75 mm and a rotational speed of 1500 rpm / min.

Example 4
In a polytetrafluoroethylene beaker (diameter: 70 mm × height: 150 mm) at 100 ° C., raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well at the blending ratio shown in Table 1. Next, trimethylene-bis (4-aminobenzoate) dissolved at 140 ° C. was put into a beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started, and it was allowed to stand at 100 ° C. for 30 minutes to be cured to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant by an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Is also shown in Table 1.

Examples 5, 11, 18
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 80 ° C., the raw materials excluding the curing agent, amine catalyst and foaming agent were mixed well at the blending ratios shown in Tables 1 to 3. Next, Etacure 300 was put into a beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started and allowed to stand at 100 ° C. for 30 minutes to cure to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam in which oil oozes out when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Is also shown in Table 1.

Example 8
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 100 ° C., raw materials excluding the curing agent, amine catalyst and foaming agent were mixed well in the blending ratio shown in Table 2. Next, trimethylolpropane was put into the beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started, and it was allowed to stand at 100 ° C. for 30 minutes to be cured to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant by an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Is also shown in Table 1.

  As shown in Table 1, Examples 1 to 20 are foams of elastic rubber having a shape in which oil oozes out when a corresponding force is applied when pressed with a finger, and is an excellent foamed solid lubricant. However, in Comparative Example 1, it was foamed but partially solidified. In Comparative Example 2, it was found that the resin component and the lubricant were separated and did not function as a foamed solid lubricant. Comparative Example 3 lacked elasticity. In addition, in Examples 1 to 20, it was found that the lubricant component was released gradually under a centrifugal force (without immediately leaving the foam).

  The foamed solid lubricant of the present invention does not exude rapidly even when the foam is deformed by an external force, and can be used by exuding the lubricating component efficiently. As a result, the amount of the lubricating component may be minimized and the service life is long. For this reason, it can be suitably used as a solid lubricant for bearings and universal joints of various industrial machines such as a stranded wire machine having a sliding member, an electric device, a printing machine, an automobile part, an electrical accessory, and a construction machine.

Claims (8)

A foamed solid lubricant formed by foaming and curing a mixture containing a lubricating component, a urethane prepolymer having an isocyanate group in the molecule, a curing agent, and a foaming agent,
The lubricating component is at least one lubricating component selected from lubricating oil and grease;
The urethane prepolymer has an isocyanate group content of 2 wt% or more and less than 6 wt%,
The blowing agent is water;
The foamed solid lubricant, wherein the mixture contains 30 to 70% by weight of the lubricating component with respect to the whole mixture, and the open cell ratio after foaming is 50% or more.   The foamed solid lubricant according to claim 1, wherein the urethane prepolymer is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer. .   The ratio of the isocyanate group and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of the curing agent / NCO) = 1 / (1.1 to 2.5). The foamed solid lubricant according to claim 1 or 2.   The ratio between the hydroxyl group of water and the functional group of the curing agent is an equivalent ratio (water hydroxyl group / functional group of the curing agent) = 1 / (0.7 to 2.0). The foamed solid lubricant according to claim 2 or claim 3.   The foamed solid lubricant according to any one of claims 1 to 4, wherein the curing agent is an aromatic polyamino compound.   6. The foamed solid lubricant according to claim 5, wherein the aromatic polyamino compound is an aromatic polyamino compound having a substituent at a position adjacent to an amino group.   The foamed solid lubricant according to any one of claims 1 to 6, wherein the mixture is foamed and hardened after being filled around a sliding member or in a molding die. . It is a manufacturing method of the foaming solid lubricant as described in any one of Claims 1 thru | or 7, Comprising: The component containing a lubrication component, the urethane prepolymer which has an isocyanate group in a molecule | numerator, a hardening | curing agent, and a foaming agent. Mixing step to obtain a mixture by mixing
A filling step of filling the mixture around a sliding member or in a mold before foaming / curing of the mixture is completed;
A foaming solid lubricant manufacturing method comprising: a foaming / curing step of foaming / curing the filled mixture.