JP2008189892A - Coating agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treating agent for a vulcanized rubber, which satisfies performances required to a coating agent for a rubbery elastomer etc., such as anti-fixation, anti-adhesion, anti-blocking and wear-resistance improvement and prevents peeling of a coating film caused by adhesion at hot-pressing or frictional wear under a high contact pressure. <P>SOLUTION: The coating agent comprises (a) a cellulose derivative, (b) 1,2-polybutadiene containing an isocyanate group and (c) at least one chosen from a wax having a softening point of 40-160°C, graphite and a fluororesin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coating agent. More specifically, the present invention relates to a coating agent for an elastic body used as a sealing material.

  Conventionally, the surface of rubber elastic bodies such as rubber-coated metal gaskets, bearing seals, oil seals, O-rings, etc. are used to prevent sticking, prevent blocking, and improve wear resistance. A coating film such as a metal salt or amide, wax such as paraffin, or silicone oil is formed, or a coating film containing ethyl cellulose, phenol resin, silicone resin, or the like as a binder is formed. Even if the coating film is formed, if the engine is further subjected to vibration under high surface pressure and high temperature use conditions such as an engine gasket, the rubber coating layer on the gasket surface may be worn and gas leakage may occur. In addition, the rubber coating layer of the rubber elastic body sliding portion such as a bearing seal or an oil seal may be worn by repeated sliding and may cause oil leakage.

In view of such a problem, the applicant previously wears or breaks the rubber coating layer on the gasket surface even under severe usage conditions such as high surface pressure and high temperature that are the usage environment of the engine head gasket. As a rubber-like elastic coating agent that can form a gasket that is effective for maintaining sealing properties, liquid 1,2-polybutadiene containing a hydroxyl group and 1,2 as its curing agent -Coating agents for rubber-like elastic bodies in which a polyolefin resin is added to a polybutadiene isocyanate group-containing material (Patent Documents 1 and 2) and a coating agent comprising an isocyanate group-containing 1,2-polybutadiene resin, a wax and a fluorine-based resin (Patent Documents) 3) is proposed.
Japanese Patent No. 2,827,402 Japanese Patent No. 3,316,993 Japanese Patent No. 3,893,985

  However, in these coating materials for rubber-like elastic bodies, the polybutadiene derivative resin, which is a component of the coating agent, sticks at a high temperature, and there is a phenomenon that the frictional wear resistance is lowered. There was a problem with resistance in

  The object of the present invention is to satisfy the performance required for coating agents for rubber-like elastic bodies such as anti-adhesion, anti-adhesion, anti-blocking and improved wear resistance, and at the time of high pressure compression and high surface pressure. An object of the present invention is to provide a surface treating agent for vulcanized rubber which does not cause peeling of the coating film due to frictional wear.

  An object of the present invention includes (a) a cellulose derivative, (b) an isocyanate group-containing 1,2-polybutadiene and (c) a wax having a softening point of 40 to 160 ° C., graphite, and a fluororesin. Achieved by coating agent.

The coating agent according to the present invention has the following effects when it is used for rubber surface treatment.
(1) Excellent coating agent applicability
(2) No blocking between surface-treated rubber
(3) The surface treated rubber surface has low friction and low sliding and excellent workability.
(4) Many chemical bonds are formed between the coating agent and the functional group of the rubber. As a result, the desired performance such as low friction and low sliding is sustained, and not only the wear of the rubber can be reduced, Due to the durability and non-adhesiveness of the surface-treated rubber, the adhesiveness and adhesion to metal are reduced, and similar effects can be seen at high temperatures.
(5) Even if the coating thickness is reduced (10 μm or less), there is no coating unevenness, it can be processed at low cost, and it has flexibility without inferior rubber properties, slipperiness and non-adhesiveness. Excellent sealing performance, especially in the case of sealing parts
(6) Since it does not contain silicone resin, silicone rubber, silicone oil, etc., it can also be used in areas where there is a risk of electrical contact problems.
(7) Since it is composed of polybutadiene derivative, cellulose derivative and at least one of wax, graphite, and fluororesin, it can be used for IT-related parts without worrying about outgassing and contamination.
(8) By including a cellulose derivative and an isocyanate group-containing 1,2-polybutadiene, it has good adhesion to wax or fluorine resin, and there is no particle contamination due to dropping off of wax particles or fluorine resin particles.
(9) Conventional treatment film containing fluororesin is hard, and seal parts suffer from deterioration in sealing performance and cracking and peeling of the film due to repeated compression-release, but contain the polybutadiene derivative (and wax) of the present invention. This gives the film flexibility and eliminates these problems.
(10) The coating property is improved by the inclusion of the cellulose derivative, and the strength of the film is improved by the reaction of the cellulose derivative and the isocyanate group-containing 1,2-polybutadiene, thereby preventing the adhesion of the polybutadiene at a high temperature. This improves the friction and wear resistance.

  As the cellulose derivative, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, carboxymethyl ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, etc., preferably methyl cellulose, carboxymethyl cellulose, carboxymethyl ethyl cellulose are used. It is used in such a proportion that it is 5 to 40% by weight, preferably 10 to 30% by weight, in each solid component in the formed film. When the proportion of cellulose in the solid component forming the film is less than this, the frictional wear resistance at high temperatures is reduced and the adhesiveness is increased. On the other hand, when it is used more than this, the adhesion to rubber is increased. Although the properties are satisfied, the slipping property is deteriorated, so that the frictional wear resistance is lowered and the adhesive strength is increased. The cellulose derivative improves the strength of the film by reaction with the isocyanate group-containing 1,2-polybutadiene, makes it possible to prevent sticking of the polybutadiene, and improves the frictional wear resistance at high temperatures.

  As the isocyanate group-containing 1,2-polybutadiene, a molecular weight of about 1,000 to 3,000 with an isocyanate group added as a terminal group is used, which is a commercial product such as Nippon Soda product Nisso TP-1001 (butyl acetate 50 wt. % -Containing solution) can be used as they are. This polybutadiene resin has better compatibility and compatibility with rubber than polyurethane resin that reacts with the same isocyanate group, and is characterized by good adhesion to rubber and particularly good wear resistance. is there.

  The isocyanate compounds used to introduce isocyanate into 1,2-polybutadiene include tolidine diisocyanate, 4,4'-diphenylmethane diisocyanate, dianisidine diisocyanate, tridene diisocyanate, hexamethylene diisocyanate, metaxylylene diisocyanate, phenyl. Isocyanate, p-chlorophenyl isocyanate, o-chlorophenyl isocyanate, m-chlorophenyl isocyanate, 3,4-dichlorophenyl isocyanate, 2,5-dichlorophenyl isocyanate, methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, n -Butyl isocyanate, octadecyl isocyanate, 1,5-naphthalene diisocyanate, polymethylene polyphenyl isocyanate, trifer Le triisocyanate, trans vinylene diisocyanate or the like is used, a commercially available example Desmodur (Bayer products), Coronate (Nippon Polyurethane products), can be used as it is Takenate (Takeda products) and the like.

  In addition, this isocyanate group-containing 1,2-polybutadiene has an isocyanate group added to the terminal group, so it reacts with 1,2-polybutadiene containing active hydrogen groups such as functional groups, hydroxyl groups and carboxyl groups on the surface of the vulcanized rubber. To make it polymerized. As the hydroxyl group-containing 1,2-polybutadiene to which a hydroxyl group is added as a terminal active hydrogen group used in this case, those having a molecular weight of about 1,000 to 3,000 are used, and commercially available products such as Nippon Soda Products Nisso G-1000, C -1000, GQ-1000, GQ-2000, etc. can be used as they are.

  When the isocyanate group-containing 1,2-polybutadiene and the active hydrogen group-containing 1,2-polybutadiene are used in combination, the isocyanate group-containing 1,2-polybutadiene is 25% by weight or more, preferably 40 to 100% by weight, Active hydrogen group-containing 1,2-polybutadiene is used in a proportion of 75% by weight or less, preferably 0 to 60% by weight. If the amount of isocyanate group-containing 1,2-polybutadiene is less than this, the adhesion to rubber will be lowered, and consequently the slipping property and non-adhesive performance will be lowered, and the friction and wear resistance will be lowered.

  Furthermore, a mixture (reaction product) obtained by mixing these active hydrogen group-containing 1,2-polybutadiene and the isocyanate compound as described above can also be used as the isocyanate group-containing 1,2-polybutadiene. In this case, the isocyanate compound is used in such a ratio that the isocyanate group has an equivalent or more equivalent to the active hydrogen group.

  This isocyanate group-containing 1,2-polybutadiene is used in a proportion of 20 to 70% by weight, preferably 30 to 60% by weight, in each solid component in the film formed using the coating agent. If the proportion of the isocyanate group-containing 1,2-polybutadiene in the solid component that forms the film is less than this, the dropping of graphite and fluororesin will increase, and the adhesion to rubber will decrease. Thus, the friction and wear resistance is lowered. On the other hand, when it is used more than this, the adhesion to rubber is satisfactory, but the slipperiness is poor, so the frictional wear resistance is lowered and the adhesive strength is increased.

  As the wax, vegetable waxes, petroleum waxes, synthetic waxes and the like having a softening point of 40 to 160 ° C, preferably 60 to 120 ° C are used. Wax increases lubricity at high temperatures, which improves wear resistance at high temperatures.However, when the amount of wax is large, it softens and adheres at high temperatures, and the film strength decreases. It begins to decline. Therefore, if a softening point higher than this is used, the slipperiness and non-adhesive performance will decrease. On the other hand, when a material having a softening point lower than this is used, the adhesion between the rubber and the treatment agent and the friction and wear resistance are lowered. Plant waxes include carnauba wax, candelilla wax, and rice wax, petroleum waxes include paraffin wax and microcrystalline wax, and synthetic waxes include polyethylene resin, Fischer-Tropsch wax, fatty acid amide, and various modified waxes. In general, a commercially available wax can be used as it is. The wax is used in a proportion of 0 to 50% by weight, preferably 10 to 40% by weight, in each solid component in the film formed using the coating agent. When the ratio of the wax in the solid component forming the film is larger than this, the adhesion with the rubber is lowered, and the frictional wear resistance is lowered.

  As graphite, scaly graphite, soil graphite, artificial graphite, etc. are used, and these can be used as they are, and this is 0 to 50 weight in each solid component in the film formed using the coating agent. %, Preferably 5 to 40% by weight. When the ratio of the wax in the solid component forming the film is larger than this, the adhesion with the rubber is lowered, and the frictional wear resistance is lowered.

  Fluorocarbon resins include polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer, polyvinylidene fluoride, polyvinyl fluoride, ethylene / tetra Fluoroethylene copolymers and the like can be mentioned, and these are used in a ratio of 0 to 60% by weight, preferably 5 to 50% by weight, in each solid component of the film formed using the coating agent. If the proportion of the fluororesin in the solid component that forms the film is higher than this, the adhesion to rubber, frictional wear resistance, and sealing properties deteriorate, and the film flexibility is impaired, resulting in a cured coating film. Cracks occur and the appearance is impaired.

  These fluororesin particles include those obtained by classifying fluororesins obtained by bulk polymerization, suspension polymerization, solution polymerization, emulsion polymerization, etc. to a particle size of about 0.1 to 10 μm, suspension polymerization, solution polymerization, emulsification. The dispersion obtained by polymerization or the like is dispersed in fine particles to about 0.1 to 10 μm by shearing stirring, etc., the one obtained by the above polymerization method is coagulated and dried, and then dry-grinded or cooled and crushed to 10 μm In the following, fine particles are used. When the particle size is set to 0.1 to 10 μm, preferably 0.1 to 5 μm, if the particle size is smaller, there is a merit that the coating thickness can be reduced, but the contact area is reduced by reducing the unevenness of the coating surface. The friction coefficient tends to increase at low surface pressure. On the other hand, if the particle size is larger, the coating thickness increases and the cost for application increases. The contact area becomes smaller and the friction coefficient decreases. Therefore, the particle diameter is appropriately adjusted according to the usage requirements, and for example, seal parts are determined in consideration of these advantages and disadvantages, and those having a particle size of about 0.5 to 2 μm are preferably used.

  Here, at least one kind of wax, graphite and fluorine-based resin is used in a proportion of 10 to 50% by weight, preferably 20 to 50% by weight. When the ratio of at least one of graphite, fluororesin and wax in the solid component forming the film is less than this, the adhesion to rubber is satisfactory, but the slipperiness and adhesive strength are increased. It is not preferable.

  Each of these essential components is dispersed in an organic solvent and prepared as a coating agent. As the organic solvent, toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-propyl ketone, cyclohexanone, phorone, isophorone, ethyl cellosolve, methyl cellosolve and the like are used. The amount of dilution with an organic solvent is appropriately selected according to the coating thickness and coating method, but is generally prepared at a solid content concentration of about 3 to 20% by weight. The coating thickness is usually 1 to 10 μm, preferably 2 to 6 μm. If the coating thickness is smaller than this, the entire rubber surface cannot be covered, and slipperiness and non-adhesiveness may be impaired. is there. On the other hand, if the coating thickness is larger than this, the rigidity of the coating surface increases, and the sealing performance and flexibility may be impaired. For use applications such as seal parts, about 2 to 6 μm is preferable.

  Examples of elastic bodies that can be treated with such a coating agent include fluorine rubber, nitrile rubber, hydrogenated nitrile rubber, ethylene-propylene (-diene) rubber, styrene-butadiene rubber, acrylic rubber, chloroprene rubber, butyl rubber, and natural rubber. General rubber materials can be mentioned, and among these, rubber materials that are less likely to bloom to the rubber surface layer such as anti-aging agents and oils blended in the rubber are preferably used. Depending on the rubber material and purpose, the blending ratio of the above components, the type of organic solvent, the amount of solvent, and the solvent mixing ratio are appropriately selected.

  Examples of the method of applying the coating agent to the rubber surface include application methods such as dipping, spraying, roll coater, flow coater, and ink jet, but are not limited to these methods. At this time, it is preferable to remove the dirt on the rubber surface by washing or the like before applying the surface treatment agent. In particular, when blooms and bleeds are deposited on the surface from rubber, washing and drying with water, detergent, solvent, etc. are performed.

  After the coating agent is applied to the rubber surface, it is heat-treated at about 150 to 250 ° C. for about 1 minute to 24 hours, for example. When the heating temperature is lower than this and the heating time is shorter than this, the curing of the film and the adhesion to the rubber are insufficient, and the non-adhesiveness and the slipping property are deteriorated. On the other hand, when the heating temperature is higher than this and the heating time is longer than this, the heat aging of the rubber occurs. Therefore, it is necessary to appropriately set the heating temperature and the heating time according to the heat resistance of various rubbers.

  For items that require a reduction in the outgas amount, heat treatment, reduced pressure treatment, extraction treatment, etc. can be carried out alone or in combination. In order to gasify the low molecular weight component in the rubber and the wax in the film, the low molecular weight component contained in the polybutadiene is preferably heat treated at about 150 to 250 ° C. for about 1 to 24 hours. The longer the time, the more effective.

  The coating agent according to the present invention is used, for example, as a coating agent for the purpose of preventing sticking of the rubber surface of a rubber metal laminate in which an adhesive layer and a rubber layer are formed on a metal plate.

  As the metal plate, a stainless steel plate, a mild steel plate, a galvanized steel plate, a SPCC steel plate, a copper plate, a magnesium plate, an aluminum plate, an aluminum die cast plate, or the like is used. These are generally used in a degreased state, and the surface of the metal is roughened by shot blasting, scotch bride, hairline, dull finishing or the like as necessary. The plate thickness is generally about 0.1 to 1 mm.

  A primer layer is preferably formed on these metal plates. The primer layer can be expected to greatly improve the heat resistance and water resistance related to rubber adhesion of the rubber metal laminate, and it is desirable to form the primer layer particularly when the rubber metal laminate is used as a sealing material.

  Primer layers include zinc phosphate coating, iron phosphate coating, coated chromate coating, vanadium, zirconium, titanium, molybdenum, tungsten, manganese, zinc, cerium compounds, especially inorganic coatings such as oxides of these metals, silane In general, commercially available chemicals such as phenolic resins, epoxy resins, polyurethane, and other organic coatings or known techniques can be used as they are. Preferably, an organometallic compound having at least one chelate ring and an alkoxy group is used. In addition, a primer layer containing a metal oxide or silica added thereto, and more preferably, a hydrolysis condensation product of an amino group-containing alkoxysilane and a vinyl group-containing alkoxysilane is added to these primer layer forming components. Used primer layerThis hydrolysis-condensation product can be used alone.

  The primer composed of the above components is prepared as a solution of an organic solvent, for example, alcohols such as methanol, ethanol and isopropyl alcohol, and ketones such as acetone and methyl ethyl ketone, so that the solid content concentration is about 0.2 to 5% by weight. Prepared.

The obtained primer solution is applied on a metal plate by spraying, dipping, brush, roll coater, etc., with a basis weight of about 50 to 200 mg / m ² , dried at room temperature or hot air, A primer layer is formed by baking at about 100 to 250 ° C. for about 0.5 to 20 minutes.

  On the primer layer, a vulcanized adhesive according to the type of rubber to be vulcanized and bonded is applied. For example, as an adhesive for NBR, it is possible to use adhesives that are generally commercially available as various resin films such as silane, phenol resin, epoxy resin, polyurethane, etc., but preferably novolac type phenol resin and resol type phenol resin. Adhesives consisting of these two types of phenolic resin and unvulcanized NBR can be used.

  Adhesives containing these components are dissolved in organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbons such as toluene and xylene, or a mixed solvent thereof and used as a liquid. .

  Formation of the adhesive layer on the metal plate is preferably performed by applying the adhesive on the metal plate on which the primer layer is formed and air-drying at room temperature, and then at about 100 to 250 ° C. for about 5 to 30. This is done by heating for about a minute.

  On the vulcanized adhesive layer formed in this way, vulcanizing agent, reinforcing agent, and other various compounding ingredients were blended into fluoro rubber, NBR, hydrogenated NBR, acrylic rubber, EPDM, chloroprene rubber, etc. Using an unvulcanized rubber compound, a rubber layer is formed by a pressure molding method such as compression molding or injection molding under molding conditions of about 150 to 220 ° C. for about 5 to 20 minutes. Alternatively, the rubber composition is dissolved or dispersed in a solvent having a boiling point of 250 ° C. or lower, such as ketones, aromatic hydrocarbons, or a mixed solvent thereof to form a rubber coating agent and then on the vulcanized adhesive layer. The rubber layer of the rubber metal laminate is formed by coating, drying, and heat-treating at about 120 to 250 ° C. under film forming conditions of about 1 minute to about 15 hours. A coating agent layer is formed on the rubber layer as described above.

  Next, the present invention will be described with reference to examples.

Examples 1-6
Example
1 2 3 4 5 6 7
Methylcellulose (Shin-Etsu Chemical) 130 100 130 130 130 130 130
10% toluene solution (13) (10) (13) (13) (13) (13) (13)
Isocyanate group-containing 1,2-65 40 65 65 65 65
Polybutadiene
(Nippon Soda product TP1001; (32.5) (20) (32.5) (32.5) (32.5) (32.5)
(Contains 50% butyl acetate)
Hydroxyl-containing 1,2-polybutadiene 19.5
(Company product G-1000) (19.5)
Isocyanate 13
(Bayer product Desmodur R) (13)
Polyethylene wax 145 72.5 72.5 145
(Molecular weight 2000, melting point 110 ° C, (21.75) (10.875) (10.875) (21.75)
(Particle size 1μm; containing 85% toluene)
Polytetrafluoroethylene 145 145 72.5 72.5
(Particle size 1μm; containing 85% toluene) (21.75) (21.75) (10.875) (10.875)
Graphite (Nichiden Carbon Products AO) 7.8 21.7 8 8 7.8
(7.8) (21.7) (8) (8) (7.8)
Toluene 653 405 679 656 557 655 680

Each component of the above coating agent (parts by weight, the solution concentration is wt%, the value in parentheses is the solid content by weight) is mixed, and this toluene solution (solid content concentration 7.5 wt%) is compression molded. Sprayed on each vulcanized fluoro rubber member (60 × 25 × 2mm), O-ring (inner diameter 119.6mm, thickness 7mm, nominal number P120) and oil seal (inner diameter 85mm, outer diameter 105mm, width 13mm) After coating the coating agent with a thickness of about 5μm using heat, heat treatment at 230 ° C for 1 hour, and then perform a dynamic friction measurement test, an adhesion test between rubber sheets at room temperature, an O-ring leak test, and an oil seal rotation test It was.
Dynamic friction measurement test: For a 2mm fluororubber sheet surface-treated as described above, according to JIS K7125, P8147, using a surface property tester made by Shinto Kagaku, a chromium steel ball friction element with a diameter of 10mm was used as the mating material. Used to measure dynamic friction coefficient under conditions of moving speed of 50mm / min and load of 50g. Room temperature adhesion test between rubber sheets: The above-mentioned surface treatment is applied to the 15mm square of the vulcanized fluoro rubber sheet bonding part, and the rubber of the bonding part After pressure bonding with each other in a constant temperature and humidity chamber at 40 ° C and 95% humidity for 24 hours at a surface pressure of 0.15 kg / cm ² , tensile shear bond strength test at room temperature according to JIS K6850 tensile shear bond strength test method Measure the tensile strength of the piece and evaluate the adhesive strength of the surface
O-ring leak test: Apply the above surface treatment to the vulcanized fluoro rubber O-ring, compress the O-ring by 5%, and measure the amount of helium leak after 3 minutes of helium gas injection with a helium leak detector. Test: Apply the above coating to the lip surface of the vulcanized fluoro rubber seal. Check if there is an oil leak 1 hour after starting the test in an oil-sealed state under the conditions of a test temperature of 100 ° C and a rotation speed of 2000rpm. It was confirmed whether there was peeling of the film.

[Production of rubber metal laminate]
Alkali degreased 0.2 mm thick stainless steel plate (Nisshin Steel Products SUS301), 1.0 parts by weight of titanium tetra (acetylacetonate), 2.5 parts by weight of alkoxysilane hydrolysis condensate, 10.0 parts by weight of water and 86.5 parts by weight of methanol Using a silane-based primer obtained by mixing and stirring for several minutes, applying by dipping method, drying with hot air, baking treatment at about 200 ° C for 5 minutes, primer layer (weight per unit: 250 mg / M ² ) was formed. In addition, the alkoxysilane hydrolysis-condensation product used here was manufactured as follows.

  A three-necked flask equipped with a stirrer, a heating jacket and a dropping funnel is charged with 40 parts by weight of γ-aminopropyltriethoxysilane and 20 parts by weight of water, and prepared by adding acetic acid so that the pH is 4-5. Stir for minutes. While further stirring, 40 parts by weight of vinyltriethoxysilane was gradually added dropwise using a dropping funnel. After completion of dropping, the mixture was heated to reflux at a temperature of about 60 ° C. for 5 hours and cooled to room temperature to obtain an alkoxysilane hydrolyzed condensate.

On this primer layer, 90 parts by weight of methyl ethyl ketone and 2 parts by weight of unvulcanized NBR (Nippon Synthetic Rubber Product N-237; Medium-High Nitrile) are added, followed by 5 weights of a resol type phenolic resin (Chemlock TS1677 manufactured by Road Far East) Apply the adhesive composition solution prepared by adding 3 parts by weight and 3 parts by weight of chlorinated polyethylene (Daiso product SE-200Z), let it air dry at room temperature, and then heat it at about 200 ° C for about 5 minutes. After forming the layer, the following NBR composition dissolved in toluene: methyl ethyl ketone = 9: 1 mixed solvent so as to have a solid content concentration of 25% by weight was applied and dried, and the uncoated layer with a thickness of about 20 μm was applied. After forming a vulcanized rubber layer, press vulcanize at 180 ° C for 6 minutes, dip-apply each of the coating agents on the surface of the formed vulcanized rubber layer, and then heat by air heating at 230 ° C for 2 minutes Processing, and a 5μm thick anti-adhesion layer So made, to prepare a rubber-metal laminate of 60 × 25 mm.
(NBR composition)
NBR (JSR product N235S; nitrile content 36%) 100 parts by weight
SRF carbon black 80 〃
White carbon (Japan silica product nip seal LP) 40 〃
Zinc oxide 5 〃
Stearic acid 2 〃
Anti-aging Agent (Nocrac 224, a new chemical product from Ouchi) 2 〃
(N-isopropyl-N′-phenyl-p-phenylenediamine)
Triallyl isocyanurate (Nippon Kasei Co., Ltd.) 2 〃
1,3-bis-tert-butylperoxyisopropylbenzene 7.5 〃
(Sanken Chemicals Sanperox TY-13)

About the obtained rubber metal laminated body, the high temperature adhesion test and high temperature friction abrasion test with an aluminum plate were done.
High temperature adhesion test with aluminum plate: A 25mm square bonded part, which is the bonded part of the rubber layer of the rubber metal laminate, is bonded at 200 ° C for 72 hours under the conditions of 200kgf / cm ² (19.6MPa), and room temperature Under the tensile shear bond strength test method of JIS K6850, the tensile strength of the tensile shear bond strength test piece is measured and the adhesive strength of the surface is evaluated. High-temperature friction and wear test: according to JIS K7125, P8147, Shinto Kagaku Using a surface property testing machine, using a hard chrome plated steel ball friction element with a diameter of 10 mm as the mating material, using a reciprocating test under conditions of a moving speed of 400 mm / min, a reciprocating moving width of 30 mm, 150 ° C, and a load of 2.5 kg. , Evaluate friction and wear, measure the number of times the rubber is worn and the adhesive layer is exposed

The results obtained in the above Examples 1 to 6 are shown in the following Table 1 together with the calculated weight ratio of the solid component forming the film of each component.
Table 1
Example
1 2 3 4 5 6 7
[Weight ratio of solids in film (%)]
Methylcellulose 17.3 19.3 19.3 17.3 19.3 17.3 17.3
NCO group-containing polybutadiene 43.3 38.6 48.4 43.2 48.3 43.2 43.3
Polyethylene wax 29.0 16.2 14.5 29.0
Polytetrafluoroethylene 42.0 28.9 16.2 14.5
Graphite 10.4 32.3 10.6 10.6 10.4
〔Evaluation results〕
Dynamic friction measurement test Dynamic friction coefficient 0.2 0.1 0.2 0.1 0.2 0.1 0.2
Room temperature adhesion test Tensile strength (kgf) 0 0 0 0 0 0 0
O-ring leak test
He leakage rate (× 10 ^-11 Pa · m ³ / sec) 5 10 10 5 5 10 5
Oil seal rotation test Leakage No No No No No No No
Presence or absence of coating film peeling No No No No No No No

High temperature adhesion test with aluminum plate Surface adhesion (kgf) 10 0 0 0 0 0 0
High temperature friction and wear test Number of times until adhesive layer is exposed 100 150 50 250 150 200 150

Comparative Examples 1-6
In Examples 1-6, the amount of each component of the coating agent was changed as follows.
Comparative example
1 2 3 4 5 6
Methylcellulose (Shin-Etsu Chemical) solution 100 100 100
(10) (10) (10)
Isocyanate group-containing polybutadiene solution 50 50 50
(25) (25) (25)
Polyethylene wax solution 125 15 30 25
(18.75) (2.25) (4.5) (3.75)
Polytetrafluoroethylene solution 125 15 250 30
(18.75) (2.25) (37.5) (4.5)
Graphite 5
(Five)
Toluene 533 313 533 63 63 120

The results obtained in Comparative Examples 1-6 are shown in the following Table 2 together with the calculated weight ratios of the solid components that form the film of each component.
Table 2
Comparative example
1 2 3 4 5 6
[Weight ratio of solids in film (%)]
Methylcellulose 69.0 69.0 53.3
NCO group-containing polybutadiene 40.0 84.7 40.0
Polyethylene wax 30.0 7.6 31.0 20.0
Polytetrafluoroethylene 30.0 7.6 60.0 31.0
Graphite 26.7
〔Evaluation results〕
Dynamic friction measurement test Dynamic friction coefficient 0.2 0.7 0.2 0.5 0.3 0.3
Room temperature adhesion test Tensile strength (kgf) 0 5.0 2.0 0 0 0
O-ring leak test
He leakage rate (× 10 ^-11 Pa · m ³ / sec) 5 100 10000 10 10000 10000
Oil seal rotation test No leak No Yes Yes No Yes Yes Yes No coating film peeling No Yes Yes Yes Yes Yes

High temperature adhesion test with aluminum plate Surface adhesion (kgf) 80 250 100 300 150 200
High temperature friction and wear test Number of times until adhesive layer is exposed 50 20 150 2 1 3

  Coating agents according to the present invention include rubber seals such as O-rings, V packings, oil seals, gaskets, packings, square rings, D rings, diaphragms, various valves, dust boots such as constant velocity joints, various valves, Effectively applied to rubber products such as diaphragms and wiper blades, storage devices such as engines, motors and hard disks, various anti-vibration rubbers such as optical disks, recording device heads such as hard disks, and shock absorbing stopper parts such as printer heads. Is done.

Claims (9)

  A coating agent comprising (a) a cellulose derivative, (b) an isocyanate group-containing 1,2-polybutadiene and (c) a wax having a softening point of 40 to 160 ° C., graphite, and a fluororesin.   The coating agent according to claim 1, wherein a mixture of an active hydrogen group-containing 1,2-polybutadiene and an isocyanate compound is used as the isocyanate group-containing 1,2-polybutadiene.   Each solid component in the formed film is composed of cellulose derivative 5 to 40% by weight, isocyanate group-containing 1,2-polybutadiene 20 to 70% by weight, softening point 40 to 160 ° C. wax 0 to 50% by weight, graphite 0 to The coating agent according to claim 1 or 2, wherein the coating agent is 50% by weight and 0 to 50% by weight of a fluororesin, and at least one of wax, graphite and fluororesin is used in a proportion of 10 to 50% by weight.   The coating agent according to claim 1 or 2, wherein the fluororesin is polytetrafluoroethylene particles having a particle diameter of 0.1 to 10 µm.   The coating agent according to claim 1 or 2, which is used by being applied to the surface of an elastic body.   The elastic body surface-treated with the coating agent of Claim 5.   The elastic body according to claim 6, wherein the surface-treated elastic body is a sealing material.   The coating agent according to claim 1 or 2, which is used by being applied to a rubber surface of a rubber metal laminate.   A rubber metal laminate in which a rubber surface is coated with the coating agent according to claim 8.