JP4512393B2 - Friction reducing agent - Google Patents

Description

  The present invention reduces the friction of the fastening material by being applied to the friction reducing agent, especially the fastening material, and also reduces the friction coefficient when tightening the fastening material, thereby realizing stable torque management. It relates to the agent.

  When fastening is performed using a combination of fastening materials such as bolts, washers, and nuts, it is necessary to stably provide the axial force necessary for fastening. Therefore, the axial force is usually generated while controlling the tightening torque. However, since the axial force generated by the torque changes depending on the mating member and the surface condition of the bolt and nut, there is a problem that it is difficult to manage the torque to stably generate the necessary axial force. is there. Further, the larger the size of the fastening material or the higher the strength of the fastening material, the higher the required tightening torque. Therefore, the variation in the axial force generated thereby tends to increase.

  In order to solve such a problem, by applying an organic material to the fastening material in the past, the required tightening torque is reduced (that is, the friction coefficient of the fastening material is reduced), and the axial force variation caused by the torque is varied. Has been done to make it smaller. As the organic material, lubricating oil (for example, mineral oil) is widely used. Further, as the organic substance, a friction coefficient reducing agent for a fastening material containing a synthetic resin or wax is also known, for example, an ether-bonded polymer such as polyethylene oxide or ethylene oxide-propylene oxide and a water-miscible synthetic resin. (See, for example, Patent Document 1).

  However, the lubricating oil has a weak adhesion strength with the surface of the fastening material to which it is applied (for example, a metal surface), so that it cannot sufficiently exert its lubricating performance when fastened with a fastening material, It is difficult to reduce the friction. Furthermore, when the friction reducing agent including the above-described ether-bonded polymer is applied to a fastening material, the application state is difficult to be uniform due to the occurrence of application spots and the friction coefficient is often not stable.

Further, the fastening material is often subjected to a surface treatment, and even if the friction reducing agent containing the lubricating oil or the ether-bonded polymer body is applied to the surface-treated fastening material, the fastening material is applied. Depending on the type of surface treatment, the friction coefficient when fastening the fastening material often varies greatly.
Japanese Patent No. 2984099

Based on the above situation, the present inventor
1) The friction of the fastening material can be reduced in the same manner as conventional friction oils or friction reducers including synthetic resins and waxes.
2) It can be applied uniformly to the fastening material, and the fluctuation of the friction coefficient of the fastening material depending on the application method can be suppressed, and 3) The friction of the fastening material can also be caused by the difference in the surface treatment applied to the fastening material. In order to obtain a friction reducing agent for a fastening material having three characteristics that the coefficient can be made constant, intensive studies were conducted. That is, the inventor of the present application examined providing a friction reducing agent having the above three characteristics 1) to 3) by combining a film forming component and an essential lubricating component.

  Further, the present inventors have studied to provide a fastening material to which such a friction reducing agent is applied, the friction material being reduced, and a proper torque management when fastening.

That is, the present invention is as follows.
(1) One or two or more fatty acid metal salts comprising a fatty acid having 8 to 30 carbon atoms and a metal selected from alkali metals, alkaline earth metals and zinc, and a water-soluble synthetic resin and a water-based synthetic resin. A friction reducing agent for a fastening material obtained by dispersing and dissolving one or more kinds of resins in water, wherein the content weight of the resin is 0.5 to 3 times the content weight of the fatty acid metal salt Friction reducing agent.
(2) One or more fatty acid metal salts comprising a fatty acid having 8 to 30 carbon atoms and a metal selected from alkali metals, alkaline earth metals and zinc,
Friction reducing agent for fastening material, wherein one or more fatty acid esters having 9 to 38 carbon atoms and one or more resins selected from water-soluble synthetic resins and aqueous synthetic resins are dispersed and dissolved in water. The friction reducing agent, wherein the resin content is 0.5 to 3 times the total content of the fatty acid metal salt and the fatty acid ester.
(3) A fastening material obtained by applying and drying the friction reducing agent according to (1) or (2).

  The fastening material coated with the friction reducing agent of the present invention has reduced friction and generates a stable coefficient of friction when fastening, regardless of the difference in surface treatment. Therefore, by using the fastening material coated with the friction reducing agent of the present invention, it is possible to perform fastening while performing appropriate torque management.

The friction reducing agent for a fastening material according to the present invention is a combination of a resin that can be a film-forming component and a fatty acid metal salt or a fatty acid ester that can be a lubricating component. It can be firmly fixed.
That is, one aspect of the friction reducing agent for a fastening material of the present invention includes 1) a fatty acid metal salt and 2) a resin selected from water-soluble synthetic resins and aqueous synthetic resins in an aqueous solvent. Moreover, another one aspect | mode of the friction reducing agent for fastening materials of this invention contains resin chosen from 1) fatty acid metal salt, 2) fatty acid ester, and 3) water-soluble synthetic resin and aqueous resin in an aqueous solvent. Furthermore, it may be preferred that the friction reducing agent of the present invention comprises a surfactant. Moreover, the other arbitrary components may be included.
The components 1) to 3) are preferably dispersed and / or dissolved in an aqueous solvent.

  The fatty acid metal salt contained in the friction reducing agent of the present invention is a salt composed of a fatty acid and a metal. The fatty acid is preferably a fatty acid having 8 or more carbon atoms in the molecule and more preferably a fatty acid having 12 or more carbon atoms from the viewpoint of lubricity and film-forming performance (film-forming property). Also, fatty acids having more than 30 carbon atoms are difficult to obtain and may not be practical.

  The carbon chain of the fatty acid is linear or branched, and may have an unsaturated bond in the carbon chain. Moreover, you may have arbitrary substituents (for example, hydroxyl group etc.) on this carbon chain.

Specific examples of preferred fatty acids include octanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, mellicic acid, oleic acid, linoleic acid, linolenic acid, Examples include isostearic acid, ricinoleic acid, 1,2-hydroxystearic acid, naphthenic acid, rosin acid and the like. More preferable examples include saturated fatty acids such as lauric acid, palmitic acid, stearic acid, montanic acid, and melicic acid, and unsaturated fatty acids such as oleic acid. Since these metal salts (for example, alkali metal salts) are solid, and solidify, the surface of the fastening material is stably and uniformly coated, and thus can be positively applied to the present invention.

  In addition, the soap manufactured from the fats and oils containing many said fatty acids may be sufficient as the fatty-acid metal salt of this invention, and these can also be used suitably.

  Examples of the metal of the fatty acid metal salt include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium, calcium and barium, and transition metals such as zinc, lead, tin, copper and bismuth. Preferably, ecological metals such as alkali metals, alkaline earth metals, and zinc are used from the viewpoint of environment and cost.

  The fatty acid metal salt of the present invention may be a fatty acid metal salt in which the above-described fatty acid and metal are arbitrarily combined. An example is calcium stearate. One of these fatty acid metal salts may be used alone, or a plurality of them may be used in combination.

  The fatty acid ester contained in the friction reducing agent of the present invention is preferably a fatty acid ester frequently used as a main component of plastic working lubricating oil, that is, one having a lubricating performance due to metal adsorption. Fatty acid esters having a small number of carbon atoms have strong solvent properties, poor lubricity, and tend to have poor film-forming properties, which may be impractical. Accordingly, the number of carbon atoms in the molecule of the fatty acid ester is preferably 9 to 38 (more preferably 13 to 36). On the other hand, fatty acid esters having 39 or more carbon atoms in the molecule may be difficult to obtain and may not be practical.

  Examples of the fatty acid ester include esters obtained by dehydration condensation of a linear fatty acid having 8 or more carbon atoms, a linear alcohol such as methanol and octanol, and a branched alcohol such as 2-ethylhexanol. It is done. Of these, saturated fatty acid esters (for example, myristyl myristate) are more preferred because they have a film-forming property. Moreover, it can be said that unsaturated fatty acid ester (for example, methyl oleate) is preferable in terms of imparting appropriate fluid lubricity to the formed film and reducing friction.

  Furthermore, the fatty acid ester is preferably a fatty acid ester that forms a high-melting film, and specific examples thereof include beef tallow oil, carnavic acid ester, and montanic acid ester.

  In addition, as the fatty acid ester, a hindered ester of alcohol having a neo type molecular structure such as neopentyl alcohol, trimethylolpropane, pentaerythritol and the like can be used.

  The fatty acid ester contained in the friction reducing agent of the present invention may be a single type of fatty acid ester or a combination of a plurality of types of fatty acid esters.

  The water-soluble synthetic resin or water-based synthetic resin contained in the friction reducing agent of the present invention preferably acts as a film-forming component for fixing the above-described fatty acid metal salt and fatty acid ester on the surface of the fastening material. As the water-soluble synthetic resin or water-based synthetic resin, many commercially available ones can be applied, and the form and type thereof are not restricted.

A water-soluble synthetic resin or water-based synthetic resin is obtained by subjecting a monomer to solution polymerization, suspension polymerization, emulsion polymerization, bulk polymerization, or a complex polymerization thereof using a solvent (organic solvent or water) or without using a solvent. It is a synthetic resin to be manufactured.

  The water-soluble synthetic resin means a resin containing an aqueous polymer such as PVA (polyvinyl alcohol), CMC (carboxymethylcellulose), PEO (polyethylene oxide).

  Examples of the aqueous synthetic resin include those obtained by subjecting the synthetic resins exemplified in the following 1 to 6 to an aqueous treatment or dispersed in water with a surfactant. That is, examples of the water-based synthetic resin include water-dispersible hydrosols, water-dispersible-soluble emulsions, and emulsions and dispersions dispersed in an aqueous solvent using a surfactant.

1. Orthophthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, trimellitic acid or its anhydride and polyhydric alcohols (glycerin, pentaerythritol, trimethylolethane, trimethylolpropane, neopentyl) Glycols, 1,4-cyclohexanedimethanol, sorbitol, etc.) are alkyd resins of long oils and short oils obtained by condensation reaction with natural oils and fatty acids. Alternatively, a modified alkyd resin in which the alkyd resin is combined with a urea resin or a melamine resin.
2. Acrylic polymerized with acrylic monomers (for example, acrylic acid, methyl methacrylate, tert-butyl methacrylate, i-butyl methacrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.) An acrylic resin which is a resin and contains dibutyl phthalate, dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, or mixed alkyl phthalate as a plasticizer as required.
3. An acrylic styrene resin obtained by copolymerizing the above acrylic monomer and styrene monomer.
4). An acrylic modified alkyd resin or a styrene modified acrylic alkyd resin obtained by adding an acrylic polymer or an acrylic styrene polymer to an alkyd skeleton (alkyd polymer).
5). A urethane alkyd resin obtained by reacting a free hydroxyl group of a mixture of monoglyceride and diglyceride of a drying oil (for example, linseed oil) with a diisocyanate.
6). Epoxy resin obtained by condensation polymerization of epichlorohydrin and diphenylolpropane.

  In the aqueous treatment of the acrylic resin or alkyd resin described above, for example, when these resins are produced, free acidic or basic functional groups are introduced into the polymer main chain, and these functional groups are acid or alkali ( For example, it can be carried out by neutralizing with diethylamine, triethylamine, diethanolamine, triethanolamine, ammonia, etc.) and introducing a hydrophilic group into the molecule. By the aqueous treatment, it can be easily dispersed in water.

  The water-based treatment of the epoxy resin described above includes 1) reacting with a maleated fatty acid to open an epoxy ring to generate a hydroxyl group, or 2) forming a free carboxylic acid group by reacting with a fatty acid, This can be done by neutralizing with an appropriate base. The water-based treatment can facilitate the dispersion in water.

  As the “water-soluble synthetic resin or aqueous synthetic resin” included in the present invention, one of the above-described resins may be used alone, or a plurality of types may be used in combination.

As described above, the friction reducing agent of the present invention may contain a surfactant. By including the surfactant, the surface activity of water in the friction reducing agent can be reduced, and the wettability to the metal surface and the uniform coating property can be improved. Further, when the fatty acid metal salt contained in the friction reducing agent is an alkaline earth metal fatty acid salt, it is preferable that a surfactant is included. This is because the alkaline earth metal fatty acid salt is difficult to disperse in water, and therefore it is preferable to improve the dispersibility with a surfactant.

  As the surfactant, any nonionic, anionic, cationic or amphoteric surfactant may be used as long as it contributes to the improvement of the dispersibility of the fatty acid metal salt and the improvement of the uniform coating property. be able to. For example, fatty acid polyhydric alcohol ester, polyoxyethylene alkyl ether, higher fatty acid metal salt, alkylbenzene sulfonate, aliphatic amine salt, carboxybetaine type and the like can be mentioned. One of these surfactants may be used alone, or a plurality of surfactants may be used in combination. However, nonionic surfactants have a strong property of promoting rusting and have foaming properties, so the addition amount may be limited to some extent, so care must be taken.

  The friction reducing agent of the present invention may further contain an optional component. For example, pigments, rust preventives, ultraviolet absorbers, anti-aging agents and the like can be mentioned. In particular, by adding a pigment, the film formed on the fastening material can be colored, thereby making it easy to confirm whether the film is formed on the fastening material and the thickness of the film. it can.

  The friction reducing agent of the present invention uses an aqueous solvent as a solvent. Since water can function as a dispersant, it is preferable not to inhibit the stability and dispersibility of the solute in water. From this viewpoint, water having low hardness is preferable. However, it can be suitably used as long as it is as hard as normal tap water.

  As described above, in the friction reducing agent of the present invention, the water-soluble synthetic resin or the water-based synthetic resin (hereinafter collectively referred to as “water-based resin”) acts as a film-forming component, and the fatty acid metal salt and The fatty acid ester can be fixed on the surface (preferably the metal surface) of the fastening material. On the other hand, since the surface of the fastening material on which the film is formed with the aqueous resin has higher friction than the surface of the fastening material coated only with the fatty acid metal salt and the fatty acid ester, It can act as a friction increasing component. Therefore, it is preferable to contain a water-based resin within a range that does not offset the friction reduction performance (high lubrication performance) of the fatty acid metal salt and the fatty acid ester.

  From the above viewpoint, the ratio of the total weight of the fatty acid metal salt and fatty acid ester contained in the friction reducing agent of the present invention to the weight of the aqueous resin is (fatty acid metal salt + fatty acid ester) :( aqueous resin) = 1: 0. It is preferably about 5 to 1: 3, more preferably about 1: 1.8 to 1: 2.2. If the aqueous resin is 3 times or less with respect to the total of the fatty acid metal salt and the fatty acid ester, the friction reducing performance of the fatty acid metal salt is hardly offset by the aqueous resin. On the other hand, if the water-based resin is 0.5 times or more of the total of the fatty acid metal salt and the fatty acid ester, the fatty acid metal salt and the fatty acid ester are easily fixed (fixed) on the surface of the fastening material, and the friction reducing agent is uniform. It is possible to suppress the variation of the friction coefficient due to the application method and the variation of the friction coefficient due to the difference in the surface treatment applied to the fastening agent. These effects are well demonstrated in the examples described below.

The total content of the water-based resin, fatty acid metal salt, and fatty acid ester contained in the friction reducing agent of the present invention is preferably 5% by weight or more based on the entire friction reducing agent. If the content thereof is small, the thickness of the film formed by applying the friction reducing agent may not be sufficient, and a reduction in the predetermined friction coefficient may not be achieved.
On the other hand, the total content of the water-based resin, the fatty acid metal salt, and the fatty acid ester is preferably 20% by weight or less with respect to the entire friction reducing agent. If the content is large, the film thickness of the coating formed on the surface of the fastening material becomes excessive. A film having an excessive film thickness generates resistance when fastening the fastening material, making it difficult to ensure a stable coefficient of friction, and for the fastening material that can be applied per fixed amount of friction reducing agent. The number is reduced, which is not preferable in terms of cost.

  The content weight ratio of the fatty acid metal salt and the fatty acid ester contained in the friction reducing agent of the present invention can be any ratio.

  When the friction reducing agent of the present invention contains a surfactant, the content of the surfactant is, as described above, from the viewpoint of improving the dispersibility of the fatty acid metal salt and improving the uniform coating property. It is preferable that it is 0.1 to 5 weight% with respect to the whole.

  The friction reducing agent of the present invention contains a fatty acid metal salt, a water-based resin, a fatty acid ester, and optionally a surfactant, and optionally other components in any order in a solvent containing water at room temperature. It can manufacture by mix | blending and stirring. The fatty acid metal salt to be blended is preferably dispersed in water or dissolved in water by separately stirring with a surfactant as necessary.

  The friction reducing agent of the present invention is used by being applied to a fastening material. In the fastening material to which the friction reducing agent of the present invention is applied, the friction is reduced, and the friction reducing agent is uniformly applied. Variations in the coefficient of friction due to differences in surface treatment applied to the material are also suppressed. As a result, when fastening is performed using the fastening material, the fastening can be performed with a low torque, and the axial force generated by the torque is constant. These effects are also described in the following test examples and examples.

  The fastening material to which the friction reducing agent of the present invention is applied is a member used for fastening members such as bolts, nuts and washers. The fastening material may be made of metal such as steel, stainless steel, aluminum, brass, or plastic, but is preferably made of metal.

  Further, the surface of the fastening material of the present invention may be subjected to any surface treatment such as chromate treatment after electrogalvanization or zinc powder chrome oxidation treatment. The friction reducing agent of the present invention can make the friction coefficient of the fastening material constant regardless of the difference in the surface treatment applied to the fastening material.

  Any method can be adopted as a method of applying the friction reducing agent of the present invention to the fastening material, and it may be appropriately selected according to the type of the fastening material. For example, 1) dip coating, 2) spray coating, 3) brush coating and the like are preferably exemplified. Moreover, although arbitrary means can be used also about the drying after application | coating, means, such as room temperature leaving drying, heating tank leaving drying, and warm air blow, are illustrated preferably. Further, a centrifugal operation may be used in combination to remove the excessively applied agent. Moreover, when using a bolt and a nut as a fastening material, although a friction reducing agent may be apply | coated to both, you may apply | coat to either (for example, bolt).

  Hereinafter, the present invention will be further described with reference to test examples and examples. However, these are examples of the present invention and do not limit the scope of the present invention.

<Test Example 1>
Samples 1 to 14 containing an acrylic-alkyd resin as a water-based resin, sodium stearate as a fatty acid metal salt, and a carnavic acid ester as a fatty acid ester were prepared according to the composition in Table 1 below. In addition, all units are% by weight, and the remainder is all water.

Moreover, each sample was prepared by adding water-based resin, fatty acid metal salt, and fatty acid ester in water in this order while stirring.

The acrylic-alkyd resin that is a water-based resin used in Test Example 1 is “a triethanolamine neutralized product of a copolymer of acrylic acid, methacrylic acid, styrene and alkyd polymer”. More specifically, 1 mol of styrene is added to 1 mol of acrylic acid, the carboxyl group of acrylic acid is neutralized with 1 mol of triethanolamine, and the terminal of the acrylic acid is combined with a methacrylic acid monomer to polymerize. , A resin having a structure grafted to an alkyd resin with 1 mol of oleic acid.
Moreover, the sodium stearate used in Test Example 1 was dissolved in water by stirring with a surfactant (polyoxyethylene stearyl ether (EO: 10 mol addition)).

  In this test example, the fastening measurement using the fastening material and the plate to be fastened was performed, and the effects of the samples 1 to 14 prepared according to the composition of Table 1 as the friction reducing agent were verified.

In this test example,
Hexagonal bolts with a thread size of M10 and a thread pitch of 1.25 with a strength category of 8.8 flange, which have been subjected to electrochromic plating and colored chromate treatment, or zinc powder chrome oxidation treatment (both of these treatments prevent And a nut of the same size as the bolt, which was subjected to colored chromate treatment after electrogalvanization.
Moreover, the to-be-clamped board was taken as the to-be-clamped board produced with the base material of a cold pressed steel plate (SPCC) material.

Samples 1 to 14 prepared according to Table 1 are dipped and applied to the bolts that have been subjected to electrochromic plating and color chromate treatment or zinc powder chrome oxidation treatment, respectively. After removing, it was dried with warm air. Tightening measurement was performed using the bolt thus obtained, the nut, and the tightened plate, and a friction coefficient was obtained according to the following formula.

  The dw can be obtained according to a calculation formula described in JIS B1084, specifically, the following calculation formula (II).

  Each test was repeated 5 times. The obtained results are shown in Table 2. In Table 2, the minimum value and the maximum value mean the minimum and maximum friction coefficients obtained in the five repetition tests, and the average value means the friction coefficient obtained in the five repetition tests. Is the average value.

  As is apparent from Tables 1 and 2, it is understood that the average value of the friction coefficient when using the bolts coated with Samples 4 to 6, 9 to 10, and 14 is 0.180 or less. In any of these samples, the content weight of the aqueous resin is in the range of about 0.5 to 3.0 times the total content weight of the fatty acid metal salt and the fatty acid ester.

  Samples 4 to 5 and 9 to 10 show that the variation of the friction coefficient due to the difference in the surface treatment applied to the bolt (colored chromate treatment or zinc powder chrome oxidation treatment) is extremely small (difference in average value is different). 0.001-0.004). For Samples 6 and 14, the variation is relatively small (average difference is about 0.02). From these results, the friction reducing agent in which the content weight of the water-based resin is in the range of 0.5 to 3.0 times the total content weight of the fatty acid metal salt and the fatty acid ester reduces the friction coefficient of the fastening material. It can be seen that the friction coefficient can be made constant irrespective of the difference in the surface treatment applied to the fastening material.

<Test Example 2>
In Test Example 2, a friction reducing agent was prepared according to the composition shown in Examples 1 to 4 below. Moreover, Comparative Examples 1-3 were prepared.

Example 1
Calcium stearate 3.7% by weight
Surfactant 0.1% by weight
Aqueous acrylic-alkyd resin 7.2% by weight
89.0% by weight of water
Example 2
Sodium stearate 2.8% by weight
Water-based acrylic-styrene resin 5.2% by weight
92.0% by weight of water
Example 3
Sodium oleate 4.0% by weight
Aqueous acrylic-alkyd resin 8.0% by weight
88.0% by weight of water
Example 4
Calcium stearate 1.0% by weight
Carnavic acid ethyl ester 3.0% by weight
Surfactant 0.1% by weight
Aqueous acrylic-alkyd resin 8.0% by weight
87.9% by weight of water

The surfactant used in the above examples is polyoxyethylene stearyl ether (EO: 10 mol addition) which is a nonionic surfactant.
The acrylic-alkyd resin, which is a water-based resin used in Examples 1, 3 and 4 above, is the same as the acrylic-alkyd resin used in Test Example 1.
The acrylic-styrene resin, which is a water-based resin used in Example 2 above, is a resin in which styrene is introduced into an acrylic chain.
In addition, the fatty acid metal salt (calcium stearate) used in Examples 1 and 4 described above incorporates a stirring step using a surfactant (polyoxyethylene stearyl ether (EO: 10 mol addition)) and dissolves in water. It has been made.

Comparative Example 1
No treatment (Do not treat friction reducer on bolts)
Comparative Example 2
Machine 10 (Oil JIS K2238 ISO VG 10)
Comparative Example 3
Commercial water-based wax-containing coating (high melting point polyethylene wax)

  In Test Example 2, the same fastening materials (bolts and nuts) and to-be-tightened plates as in Test Example 1 were used, and the bolts were subjected to color chromate treatment or zinc powder chrome oxidation treatment after electrogalvanization treatment in the same manner as in Test Example 1. Was given.

  The agents of Examples 1 to 4 and Comparative Examples 2 to 3 are dip coated on the colored chromate-treated or zinc powder chrome oxidation-treated bolt, and the excess coating solution is removed using a centrifugal separator. Dried. Further, in Comparative Example 1, a bolt that did not perform such application was used. The bolt and the nut thus obtained were tightened on the tightened plate to perform tightening measurement, and the friction coefficient was obtained according to the above formula (I).

  Five repeated experiments were performed for each test. The obtained results are shown in Table 3. In addition, the maximum value and the minimum value mean the maximum and minimum friction coefficients obtained in five repetition experiments, and the average value is the average value of the friction coefficients obtained in five repetition experiments. It is.

  As is apparent from Table 3, the average value of the friction coefficient obtained by tightening measurement using a bolt that is not treated with the agent as in Comparative Example 1 is 0.3 or more. Further, the difference between the minimum value and the maximum value is 0.063 and 0.048, and the difference between the average values of the friction coefficients due to the difference in the surface treatment is 0.037.

On the other hand, the coefficient of friction obtained by tightening measurement using the bolt processed by the machine 10 that is the machine oil of Comparative Example 2 is 0.22 or less on average regardless of the difference in surface treatment. It can be seen that the friction is reduced to some extent as compared with 1 (untreated product). Further, the difference between the minimum value and the maximum value is also 0.016 and 0.027, and the difference between the average values of the friction coefficients due to the difference in the surface treatment is 0.028. In both cases, blurring is suppressed to some extent.
Moreover, the friction coefficient obtained by the fastening measurement using the bolt treated with the commercially available water-based wax of Comparative Example 3 was 0.17 or less on average regardless of the difference in the surface treatment, which was further higher than that of Comparative Example 2. It can be seen that the friction is reduced. However, the difference between the minimum value and the maximum value is 0.035 and 0.036, which is larger than that of Comparative Example 2, and the difference in the coefficient of friction due to the difference in the surface treatment is 0.026. It turns out that it has not improved.

  On the other hand, the friction coefficients obtained from the tightening measurement using the bolts coated with the agents of Examples 1 to 4 are all 0.170 or less, and the friction is reduced compared to any of Comparative Examples 1 to 3. You can see that Further, it can be seen that the difference between the minimum value and the maximum value of the friction coefficient in each measurement is as small as 0.013 at the maximum, and the fluctuation of the friction coefficient due to coating is also small. Furthermore, the difference of each average value of the friction coefficient by the difference in surface treatment is also suppressed to 0.001-0.003 (difference of average value), and it turns out that the friction coefficient is very stable.

From these results, the friction reducing agent of the present invention is uniformly applied to the fastening material to achieve 1) low friction of the fastening material,
2) Friction coefficient friction due to the application method can be reduced,
3) It can be seen that the coefficient of friction can be made constant regardless of the difference in the surface treatment applied to the fastening material.

Claims (3)

One or more fatty acid metal salts comprising a fatty acid having 8 to 30 carbon atoms and a metal selected from alkali metals, alkaline earth metals and zinc;
A friction reducing agent for a fastening material obtained by dispersing and dissolving one or more kinds of resins selected from carnavic acid esters , water-soluble synthetic resins and aqueous synthetic resins in water, wherein the weight of the resin is the fatty acid A friction reducing agent that is 0.5 to 3 times the total content of metal salt and fatty acid ester. The friction reducing agent according to claim 1, further comprising a surfactant.   A fastening material obtained by applying and drying the friction reducing agent according to claim 1.