JP4206377B2 - Resin oil body and method for producing the same - Google Patents

Description

  The present invention relates to a resin oil retaining body and a method for producing the same, and more particularly to a resin oil retaining body that can be used as a lubricant supply body and a method for producing the same.

As one of methods for improving the friction and wear characteristics of a resin molded body, a so-called “gunpla” in which a lubricating oil is added to a resin material has been conventionally known. This method involves melt-kneading resin and lubricating oil and injection molding or extrusion molding of the raw material shape prior to molding by pelletizing. The maximum amount of lubricating oil that can be added is 10% to prevent deterioration of injection moldability. It is about volume%. Since the resin and the lubricating oil are melt-kneaded, the uniformity and oil retention are high, and the lubricating oil does not ooze out to the surface. For this reason, the function as a lubricating oil supply body is not sufficient, and when the resin material is used as a sliding bearing or the like, sufficient lubrication characteristics are obtained in a region where the PV value obtained by multiplying the load (P) and the sliding speed (V) is high. Cannot be obtained.
Conventionally, a composition containing ultra high molecular weight polyethylene and grease is disclosed as an oil-impregnated resin that has been developed to deal with the above-mentioned problems, and that is obtained by pre-mixing resin and lubricating oil into a predetermined shape. (Patent Document 1). Since the composition prevents the lubricating oil from flowing by the grease, the amount of lubricating oil in the resin can be 50% by volume or more. Further, the amount of lubricating oil oozing out to the surface is larger than that of Gundam.
Also disclosed are oil-impregnated resins in which a fibrous oil conducting material is added (Patent Documents 2 to 4), and those in which lubricating oil is retained in porous silica are mixed with a synthetic resin to obtain an oil-impregnated resin. (Patent Document 5). These are all intended to continuously supply lubricating oil to the resin surface. The amount of lubricating oil in the resin is increased to about 20% by volume with the aid of a conductive material and porous silica. Yes.
In addition, a method of impregnating a resin that has been sintered and molded into a predetermined shape with a lubricating oil is disclosed (Patent Documents 6 and 7). Considering the close-packing and compression in the molding process, the effective porosity is 30% at the maximum, and this void content is the oil content.
JP-A-6-41569 Japanese Patent Laid-Open No. 11-166541 JP 2000-71243 A JP 2000-71244 A JP 2002-129183 A Japanese Patent Laid-Open No. 61-6429 JP-A-9-76371

However, in Patent Document 1, a sufficient amount of oil is secured, but since it is a kneading type in which a resin and a lubricant are mixed in advance, the oil retaining property is high and the utilization efficiency of the added lubricating oil is low. Further, in the case of the kneading type, there is a problem that the mechanical strength of the oil-containing resin molded product is lowered when the amount of lubricating oil is increased.
In Patent Document 2, Patent Document 3, Patent Document 4, and Patent Document 5, as described above, the amount of lubricating oil in the resin is increased to about 20% by volume by the conductive material and porous silica, and the mechanical material is added by adding a reinforcing material. Although it is possible to suppress a decrease in mechanical strength, there are problems such as insufficient lubrication amount and slow oozing speed when applied to bearing cages or the like and lubricated only with oil in the resin.
In addition, the above Patent Documents 1 to 5 are methods in which a resin and lubricating oil previously kneaded are made into a predetermined shape, so there are restrictions on combinations of resin and lubricating oil, and they are applicable to a wide range of applications. There is a problem that you can not.
On the other hand, Patent Document 6 and Patent Document 7 increase the degree of freedom of the combination of the resin and the lubricating oil, but the resins that can actually be sintered and molded are limited to ultrahigh molecular weight polyethylene, polyimide resin, and the like. In addition, as described above, the actual communication porosity is 30% at the maximum, and when it is applied to bearing cages and lubrication is performed only with the oil content in the resin, the amount of lubricating oil is insufficient. However, there is a problem that it cannot withstand the demand for longer life in recent years.

On the other hand, a desalting method is known as a method for producing an inexpensive porous body that can adjust the communication porosity. In the desalting method, a molding material obtained by adding a powdery pore forming material such as sodium chloride or sodium sulfate to a resin or rubber is molded as a solid molded body including the pore forming material, and the resulting solid molded body is washed with water. This is a method for producing a porous body, in which the pore-forming material is eluted by washing, etc., and pores are formed in the portion where the pore-forming material was present.
Conventionally, a porous body having a high communication porosity by a desalting method is solid at room temperature, but is melted and present in a liquid state at a molding temperature of a polymer material forming a skeleton of the porous body. A porous material is molded using a pore-forming material that can be formed (see Patent Document 8), and a molding material in which the particulate pore-forming material is dispersed in a polymer substance at a temperature at which a part of the particulate pore-forming material melts. A molded porous body that does not dissolve the polymer substance but forms the pores by washing the pore-forming material with a solvent that dissolves the molded body (see Patent Document 9), particularly, a polyolefin porous body having open cells. (See Patent Document 10).
Moreover, in order to facilitate the separation of the extract and the reuse of the extract, there is one in which this is extracted with warm water using a pore-forming material made of a water-soluble powder (see Patent Document 11).

Sodium chloride, ammonium chloride, sodium sulfate, sodium nitrate, potassium sulfate, magnesium sulfate, calcium chloride and the like disclosed as pore forming materials in each of the above patent documents are relatively easy to dissolve in water, and are inexpensive and easily available. It is effective as a pore-forming material used for producing a porous body having a large pore diameter. However, when forming fine pores, it is difficult to completely dissolve and extract the pore-forming material. For this reason, in applications that may come into contact with steel, there is a risk that this non-extracted pore forming material oozes out during use and rusts the steel. Therefore, when such a porous body is impregnated with a lubricating oil and used as a resin oil retaining body, it is unsuitable for use in a rolling bearing or a sliding bearing having steel around it.
JP 2001-2825 A (paragraph “0011”) JP 2002-194131 A (paragraph “0009”) JP 2002-60534 A (paragraph “0004”) JP 2002-322310 A (paragraphs “0007” and “0008”)

  The present invention has been made in order to address such problems, and in a porous resin oil retaining body containing lubricating oil, the oil content is large, the use efficiency of the lubricating oil is excellent, and the use and specifications are An object of the present invention is to provide an oil retaining body made of a porous resin that can be combined with a corresponding resin and lubricating oil. It is a resin oil retaining body that is used especially for applications that come into contact with metal parts, etc., and does not rust the steel even if the pore forming material that has not been extracted from the oil retaining body oozes out during use. An object is to provide an oil body and a method for producing the same.

The resin oil retaining body of the present invention is a resin oil retaining body in which a resin porous body having communication holes is impregnated with oil, and the communication holes are blended with a pore forming material made of an alkaline compound . It is a communication hole obtained by molding a resin into a molded body and then extracting the pore-forming material from the molded body using a solvent that dissolves the pore-forming material and does not dissolve the resin. And
Further, the oil impregnated in the resin is a lubricating oil.
The pore forming material is a substance having a melting point higher than the molding temperature of the resin. In particular, the pore forming material is a water-soluble substance.
The resin oil retaining body has a communication pore ratio of 30% or more.

The pore forming material is an alkaline compound. The alkaline compound is at least one metal salt selected from an organic alkali metal salt and an organic alkaline earth metal salt, and also sodium benzoate, sodium acetate, sodium sebacate, sodium triphosphate, pyrophosphate It is characterized by being sodium or potassium carbonate.
The method for producing a resin oil retaining body of the present invention includes a step of blending a pore-forming material with a resin, a step of molding a resin containing the pore-forming material into a molded body, and dissolving the pore-forming material. In addition, the method includes a step of extracting the pore forming material from the molded body using a solvent that does not dissolve the resin, and a step of impregnating the obtained resin porous body with a lubricating oil.

The resin oil retaining body of the present invention is excellent in the oil content and its utilization efficiency, and can impart lubricity for a long period of time. Further, since the molded resin porous body is not impregnated with the lubricating oil but is impregnated with the oil after forming the pores, the resin and the oil can be arbitrarily selected according to the use and specification.
In addition, as a pore-forming material used for the production of a resin oil retaining body, not an acidic salt but an alkaline salt, especially an organic alkali metal salt that plays a role of a rust preventive agent, etc. In the case of using the resin oil retaining body, rusting of the steel can be prevented even if the pore forming material remaining in the oil retaining body oozes out.

The resin oil retaining body of the present invention is a solvent that does not dissolve the pore-forming material after molding the pore-forming material, particularly a resin containing an alkaline pore-forming material into a molded body. It is obtained by impregnating a resinous porous body having communication holes obtained by extracting the pore forming material from the molded body with a lubricating oil or the like. By using an organic alkali metal salt or the like as the alkaline pore-forming material, even if the pore-forming material is not completely dissolved and extracted, the pore-forming material acts as a rust preventive agent. It can also be suitably used when there is a problem.
Hereinafter, the resin, the pore forming material, the molding method, the extraction method and the like constituting the resin oil retaining body of the present invention will be described.

As the resin of the present invention, resin powder and pellets such as thermoplastic resin, thermosetting resin, elastomer or rubber can be used. The particle size and shape of the resin powder and pellets are not particularly limited when melt molding because they are kneaded with the pore forming material at the time of melting. In the case of dry blending and compression molding as it is, those of 1 to 500 μm are preferable.
Examples of the thermoplastic resin or thermosetting resin include polyethylene resins such as low density polyethylene, high density polyethylene, and ultrahigh molecular weight polyethylene, modified polyethylene resins, water-crosslinked polyolefin resins, polyamide resins, aromatic polyamide resins, polystyrene resins, Polypropylene resin, silicone resin, urethane resin, polytetrafluoroethylene resin, chlorotrifluoroethylene resin, tetrafluoroethylene / hexafluoropropylene copolymer resin, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin, vinylidene fluoride resin , Ethylene / tetrafluoroethylene copolymer resin, polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene ether resin, Recarbonate resin, aliphatic polyketone resin, polyvinylpyrrolidone resin, polyoxazoline resin, polyphenylene sulfide resin, polyethersulfone resin, polyetherimide resin, polyamideimide resin, polyetheretherketone resin, thermoplastic polyimide resin, thermosetting Examples thereof include a functional polyimide resin, an epoxy resin, a phenol resin, an unsaturated polyester resin, and a vinyl ester resin. Moreover, the mixture of 2 or more types of materials chosen from the said synthetic resin, ie, a polymer alloy, etc. can be illustrated.

Among the resins mentioned above, resins that can be used for industrial applications such as automobile parts, machine parts, electrical / electronic parts, etc. are preferable, and in particular, a tensile strength of 49 MPa or more, a flexural modulus of 1.9 GPa or more, and a heat resistance of 100 ° C. or more. Engineering resin with heat resistance (heat deformation temperature (18.6 kg / cm ² )), special engineering resin or super engineering resin that has higher heat resistance and can be used for a long time even at high temperatures of 150 ° C or higher, and mechanical properties such as sliding characteristics Resins that can be used in industrial applications are preferred because some of their properties or thermal properties are particularly excellent.
Specific examples of preferred resins that can be used in the present invention include polyetheretherketone resins, polyphenylene sulfide resins, polyamideimide resins, thermoplastic polyimide resins, thermosetting polyimide resins, polyamide 9T resins, epoxy resins, polytetrafluoroethylene. Examples include resins, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resins, unsaturated polyester resins, and ultrahigh molecular weight polyethylene.

  Examples of the elastomer or rubber include acrylonitrile butadiene rubber, isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, butyl rubber, acrylic rubber, silicone rubber, fluorine rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, chlorinated Examples thereof include vulcanized rubbers such as polyethylene rubber and epichlorohydrin rubber; and thermoplastic elastomers such as polyurethane elastomer, polyester elastomer, polyamide elastomer, polybutadiene elastomer, and soft nylon elastomer.

As the pore-forming material that can be used in the present invention, a resin containing the pore-forming material is molded into a molded body, and then the pore-forming material is dissolved and a solvent that does not dissolve the pore-forming material-containing resin is used. Any substance that can be extracted from the resin molding can be used.
In particular, as the pore forming material, a weak alkali salt that can be used as a rust inhibitor can be preferably used. Examples of the weak alkali salt include organic alkali metal salts, organic alkaline earth metal salts, inorganic alkali metal salts, inorganic alkaline earth metal salts, and the like. Even when an unextracted part falls off, an organic alkali metal salt or an organic alkaline earth metal salt is preferably used because it is relatively soft and hardly damages a rolling surface or a sliding surface. In addition, you may use these metal salts 1 type or in mixture of 2 or more types. In addition, it is preferable to use a water-soluble weak alkali salt because inexpensive water can be used as a cleaning solvent, and waste liquid treatment at the time of pore formation is facilitated.

In order to prevent dissolution of the pore-forming material during molding, it is preferable to use a substance having a melting point higher than the molding temperature of the resin used for the pore-forming material.
Water-soluble organic alkali metal salts that can be suitably used in the present invention include sodium benzoate (melting point 430 ° C.), sodium acetate (melting point 320 ° C.) or sodium sebacate (melting point 340 ° C.), sodium succinate, stearic acid Sodium etc. are mentioned. Sodium benzoate, sodium acetate, or sodium sebacate is particularly preferred because of its high melting point, compatibility with various resins, and high water solubility.
Examples of the inorganic alkali metal salt include sodium molybdate, potassium molybdate, sodium tungstate, sodium triphosphate, sodium pyrophosphate, potassium carbonate, and the like.

The pore-forming material can be used as a mixture of a substance having a melting point higher than the molding temperature of the resin and a substance having a melting point lower than the molding temperature of the resin.
Examples of the substance having a melting point lower than the molding temperature of the resin include pentaerythritol and boric acid (171 ° C.).

The particle size of the pore forming material is preferably controlled to 1 to 500 μm.
The ratio of the pore forming material is 30% by volume to 90% by volume, preferably 40% by volume to 90% by volume, with respect to the total amount including other materials such as resin powder, porous body forming material and filler. If it is 30% by volume or less, the pores of the porous body are hardly formed into continuous pores, and if it is 90% by volume or more, desired mechanical strength cannot be obtained.
Moreover, you may mix | blend the filler insoluble in the solvent used for extraction of a pore formation material at the time of a mixing | blending. For example, when the solvent is water, glass fiber, carbon fiber, or the like may be blended for the purpose of improving the mechanical strength of the porous body.

The mixing method of the resin material and the pore forming material is not particularly limited, and a kneading method generally used for mixing the resin such as dry blending and melt kneading can be applied.
Alternatively, a method may be used in which the pore-forming material is dissolved in a liquid solvent to form a transparent solution, and then resin powder is dispersed and mixed in the solution, and then the solvent is removed.
The method of dispersing and mixing is not particularly limited as long as it can be mixed in a liquid, and examples thereof include a ball mill, an ultrasonic disperser, a homogenizer, a juicer mixer, and a Henschel mixer. It is also effective to add a small amount of a surfactant in order to suppress separation of the dispersion. In addition, when mixing resin with the transparent solution of a pore formation material, the amount of solvent is ensured so that a pore formation material may melt | dissolve completely by mixing. In this case, as a method for removing the solvent, methods such as heat evaporation, vacuum evaporation, bubbling with nitrogen gas, dialysis, and lyophilization can be used. Since the method is easy and the equipment is inexpensive, it is preferable to remove the liquid solvent by heat evaporation.
For molding a mixture in which a pore molding material is blended with a resin, any molding method such as compression molding, injection molding, extrusion molding, blow molding, vacuum molding, transfer molding or the like can be employed. Moreover, in order to improve workability | operativity before shaping | molding, you may process into a pellet, a prepreg, etc.

Extraction of the pore-forming material from the obtained molded body is performed by washing the molded body with a solvent that dissolves the pore-forming material and does not dissolve the resin.
As the solvent, for example, water and alcohol solvents, ester solvents, ketone solvents, and the like can be used as solvents compatible with water. Among these, it is appropriately selected according to the above conditions depending on the type of resin and pore forming material. These solvents may be used alone or in combination of two or more. It is preferable to use water because of its advantages such as easy waste liquid treatment and low cost.
By performing the extraction treatment, a resin porous body having pores formed in the portions filled with the pore forming material is obtained.

The resin oil retaining body of the present invention can be obtained by impregnating the resin porous body with a lubricating oil.
The impregnating lubricating oil is not particularly limited and is generally used, mineral oil (paraffinic or naphthenic), synthetic lubricating oil (poly-α-olefin (PAO), ester oil, cyclopentane oil, fluorine oil (PFPE) ), Silicone oil, phenyl ether oil) and the like. If necessary, so-called lubricating oil additives such as antioxidants, extreme pressure agents, friction modifiers, and rust inhibitors may be added.
The impregnation method may be any method that can impregnate the resin porous body. The pressure reduction impregnation in which the resin porous body is immersed in an impregnation tank filled with lubricating oil and then impregnated under reduced pressure is preferable. Further, when a high viscosity silicone oil or the like is used, it can be impregnated under pressure. It is good also as a pressure-reduced-pressure impregnation combining these.

Example 1
A mixed powder was obtained by mixing ultra-high molecular weight polyethylene powder of 1: 1 volume ratio (Miperon XM220 manufactured by Mitsui Chemicals, Inc.) and sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) for 5 minutes with a mixer. . Using this mixed powder, a disk having a diameter of 30 × thickness t 5 mm was molded by a heat compression molding method (200 ° C. × 30 minutes). The molded body was washed with warm water at 80 ° C. for 10 hours with an ultrasonic cleaner to elute the sodium benzoate powder. Thereafter, it was dried at 100 ° C. for 8 hours to obtain a porous body having a communication porosity of 43%. 7% by volume of sodium benzoate was not eluted and remained in the porous body. The porous body was allowed to stand in a beaker containing synthetic lubricating oil PAO (Sinfluid 801, manufactured by Nippon Steel Chemical Co., Ltd.) and impregnated in a vacuum chamber for 60 minutes. As a result, a resin oil retaining body containing 93% by volume with respect to a communication pore ratio of 43% and 40% by volume with respect to the entire resin oil retaining body was obtained.

Reference Example 3
Volume ratio 2: 1: 1 polyphenylene sulfide resin powder (T4AG manufactured by Dainippon Ink, Ltd., melting point 280 ° C), sodium benzoate powder (reagent manufactured by Wako Pure Chemical Industries, Ltd., melting point 430 ° C) and pentaerythritol (Japanese A mixed powder was obtained by mixing a reagent (melting point: 260 ° C.) manufactured by Kojunyaku Co., Ltd. with a mixer for 5 minutes. Using this mixed powder, a disk having a diameter of 30 × thickness t 5 mm was molded by a heat compression molding method (320 ° C. × 30 minutes). The molded body was washed with warm water at 80 ° C. for 10 hours with an ultrasonic cleaner to elute sodium benzoate and pentaerythritol. Thereafter, it was dried at 100 ° C. for 8 hours to obtain a porous body having a communication porosity of 49%. 1% by volume of sodium benzoate powder was not eluted and remained in the porous body. The porous body was allowed to stand in a beaker containing synthetic lubricating oil PAO (Sinfluid 801, manufactured by Nippon Steel Chemical Co., Ltd.) and impregnated in a vacuum chamber for 60 minutes. As a result, a resin oil retaining body containing 98% by volume with respect to a communication pore ratio of 49% and 48% by volume with respect to the entire resin oil retaining body was obtained.

Reference Example 1
Ultra-high molecular weight polyethylene powder (Miplon XM220 manufactured by Mitsui Chemicals, Inc.) and pentaerythritol (melting point 260 ° C., alcohols) in a volume ratio of 1: 1 were mixed for 5 minutes with a mixer to obtain a mixed powder. Using this mixed powder, a disk having a diameter of 30 × thickness t 5 mm was molded by a heat compression molding method (200 ° C. × 30 minutes). This molded product was washed with warm water at 80 ° C. for 10 hours with an ultrasonic cleaner to elute pentaerythritol. Thereafter, it was dried at 100 ° C. for 8 hours to obtain a porous body having a communication porosity of 41%. 9% by volume of pentaerythritol was not eluted and remained in the porous body. The porous body was allowed to stand in a beaker containing synthetic lubricating oil PAO (Sinfluid 801, manufactured by Nippon Steel Chemical Co., Ltd.) and impregnated in a vacuum chamber for 60 minutes. As a result, a resin oil retaining body containing 93% by volume with respect to a communication porosity of 41% and 38% by volume with respect to the entire resin oil retaining body was obtained.

Reference Example 2
Ultra-high molecular weight polyethylene powder (Miplon XM220 manufactured by Mitsui Chemicals, Inc.) with a volume ratio of 1: 1 and sodium chloride powder (reagent manufactured by Wako Pure Chemical Industries, Ltd.) were mixed for 5 minutes with a mixer to obtain a mixed powder. Using this mixed powder, a disk having a diameter of 30 × thickness t 5 mm was molded by a heat compression molding method (200 ° C. × 30 minutes). This molded body was washed with warm water at 80 ° C. for 10 hours with an ultrasonic cleaner to elute the sodium chloride powder. Thereafter, it was dried at 100 ° C. for 8 hours to obtain a porous body having a communication porosity of 46%. 4% by volume of sodium chloride was not eluted and remained in the porous body. The porous body was allowed to stand in a beaker containing synthetic lubricating oil PAO (Sinfluid 801, manufactured by Nippon Steel Chemical Co., Ltd.) and impregnated in a vacuum chamber for 60 minutes. As a result, a resin oil retaining body containing 98% by volume with respect to the communication hole ratio of 46% and 45% by volume with respect to the entire resin oil retaining body was obtained.

Comparative Example 1
Ultra high molecular weight polyethylene powder (Miperon XM220 manufactured by Mitsui Chemicals) 100 parts by weight, grease (Showa Shell Sekiyu Albania No. 3) 35 parts by weight, oil (Mobil Sekiyu DTE Heavy Mediam) 35 parts by weight A test piece of a disk having a diameter of φ30 × thickness of t5 mm was obtained by cutting what was fired at 150 ° C.

上記、数１において、各符号の意味を以下に示す。
Ｖ；洗浄前成形体の体積
ρ；洗浄前成形体の密度
Ｗ；洗浄前成形体の重量
Ｖ₁；樹脂粉末の体積
ρ₁；樹脂粉末の密度
Ｗ₁；樹脂粉末の重量
Ｖ₂；気孔形成材の体積
ρ₂；気孔形成材の密度
Ｗ₂；気孔形成材の重量
Ｖ₃；洗浄後の樹脂多孔質体の体積
Ｗ₃；洗浄後の樹脂多孔質体の重量
Ｖ'₂；洗浄後に樹脂多孔質体に残存する気孔形成材の体積 In addition, in each Example, a communicating porosity means the ratio for which the total volume of the pores which are mutually continuous in a resin molding accounts to the volume of a resin molding.
Specifically, the communication porosity was calculated by the method shown in Equation (1) in Equation 1.

In the above Equation 1, the meaning of each symbol is shown below.
V; volume ρ of molded body before cleaning; density W of molded body before cleaning; weight V _{1 of} molded body before cleaning; volume ρ _{1 of} resin powder; density W _{1 of} resin powder; weight V _{2 of} resin powder; Volume ρ _{2 of} material; density W _{2 of} pore forming material; weight V ₃ of pore forming material; volume W ₃ of resin porous body after washing; weight V ′ ₂ of resin porous body after washing; resin after washing Volume of pore-forming material remaining in the porous body

Rust test The disks produced in the examples and comparative examples are sandwiched between SPCC steel plates (40 × 40 × t 2), and the wet test method specified in JISK2246 “rust prevention oil” (49 ± 1 ° C, relative temperature 95% or more) A rust test was conducted. The rusting conditions of the mating surfaces after 192 hours (h), 384 hours (h), and 576 hours (h) were compared. The results are shown in Table 1.

Oil release amount test The disks produced in the examples and comparative examples were sandwiched between filter papers, pressurized by placing weights and allowed to stand for 100 hours, and then the amount of oil transferred to the filter papers was measured. The ratio of the released oil to the total volume of the test piece is shown in Table 1.

As shown in Table 1, in Example 1 according to the present invention, it was confirmed that the oil retaining body has a sufficient oil absorbing ability. In the rust test, no rust was observed in Example 1 even after 576 hours. This is considered that the sodium benzoate used as a pore forming material is acting as a rust preventive agent.
The oil-containing porous bodies of each of the examples and the reference examples are superior in oil-releasing properties as compared to the comparative examples in which grease and oil are mixed, and thus can be said to have high lubricity. However, when this oil-containing porous body is used for applications where it comes into contact with steel, sodium chloride ( Reference Example 2 ), which is a pore-forming material that rusts steel, is not preferred.

  Since the resin oil retaining body of the present invention is excellent in rust prevention, it can be suitably used for applications having steel around it, such as rolling bearings and sliding bearing cages.

Claims (8)

A resin oil retaining body in which a resin porous body having communication holes is impregnated with oil, and the communication holes are formed by molding a resin in which a pore forming material made of an alkaline compound is blended to form a molded body A resin oil retaining body, which is a communication hole obtained by extracting the pore forming material from the molded body using a solvent that dissolves the pore forming material and does not dissolve the resin.   The resin oil retaining body according to claim 1, wherein the oil is a lubricating oil.   The resin oil retaining body according to claim 1 or 2, wherein the pore forming material is a substance having a melting point higher than a molding temperature of the resin.   4. The resin oil retaining body according to claim 1, wherein the pore forming material is a water-soluble substance.   The resin oil retaining body according to any one of claims 1 to 4, wherein the communication porosity is 30% or more.   The resin oil retaining body according to claim 1, wherein the alkaline compound is at least one metal salt selected from an organic alkali metal salt and an organic alkaline earth metal salt. The alkaline compound, sodium benzoate, sodium acetate, sodium sebacate, sodium triphosphate, resin of claim 1, wherein the at least one compound selected from sodium or potassium carbonate pyrophosphate Oil retaining body. A step of blending a resin with a pore-forming material composed of an alkaline compound, a step of molding a resin containing the pore-forming material to form a molded body, and a solvent that dissolves the pore-forming material and does not dissolve the resin. A method for producing a resin oil retaining body, comprising: a step of extracting the pore forming material from the molded body, and a step of impregnating the obtained resin porous body with a lubricating oil.