JP4984533B2 - Fluoro rubber coating agent - Google Patents

Description

  The present invention relates to a fluororubber coating agent. More specifically, the present invention relates to a fluororubber coating agent used for forming a rubber layer of a rubber metal laminate suitably used as a gasket material or the like.

The present applicant has previously described fluororubber, polyol-quaternary ammonium salt or fourth phosphonium salt-based vulcanization accelerator (polyol-quaternary onium salt-based vulcanizing agent), amine-based vulcanizing agent and magnesium oxide acid acceptor. By applying a fluororubber coating solution composed of a ketone-alcohol mixed solvent solution of a fluororubber compound containing a primer to a metal plate coated with a primer, a heat-resistant fluororubber coat can be provided on the metal plate and used there. It has been found that the fluororubber coating solution is also excellent in stability over time. However, although the fluororubber-coated metal plate thus obtained achieves the intended purpose, the rubber layer may peel off or blister when immersed in a high-temperature antifreeze solution for a long time.
JP-A-2-248453

Therefore, in order to improve the peeling of the rubber layer and the stability of the coating solution over time and to improve the productivity, basic magnesium as an acid acceptor is used when coating the surface of the above-mentioned fluororubber coating solution on the metal plate.・ Although the use of aluminum, hydroxy, carbonate and a novolac-type phenolic resin-containing primer was proposed by the present applicant, this also achieved the intended purpose, but the adhesion to the metal plate immediately after vulcanization A new problem has been found that the rubber layer may peel off or flow due to compression under high temperature and high surface pressure.
JP 11-34226 A

  The object of the present invention is to receive (A) fluororubber, (B) polyol vulcanizing agent, (C) quaternary onium salt vulcanization accelerator and (D) basic magnesium / aluminum / hydroxy / carbonate hydrate. In a fluororubber coating agent composed of an organic solvent solution of a fluororubber compound containing an acid agent, when a rubber metal laminate is produced using it, the adhesiveness to the metal plate immediately after vulcanization, high temperature, and high surface pressure It is an object of the present invention to provide a fluororubber coating agent that does not cause peeling or flow in the rubber layer due to compression of.

An object of the present invention is to provide a fluororubber coating agent comprising an organic solvent solution of the fluororubber compound, wherein (E) a metal stearate and a heptanoic acid Ca salt are further used in the fluororubber compound. In addition, the addition of inorganic fillers is also effective. It is also effective to add a flat filler, a plate filler, a columnar filler, or a needle filler (fibrous filler), and it is more effective when used in combination with an inorganic filler.

The fluororubber coating agent according to the present invention is effective not only for the stability over time of the coating liquid and the reduction of adhesion with the metal plate immediately after vulcanization, but also for the rubber metal laminate produced using this, Even when immersed in antifreeze or oil for a long time, there is no peeling or blistering of the rubber layer, and there is no peeling or flow of rubber due to compression under high temperature and high surface pressure. . This effect is Mirare when used in combination of two or more metal salts having different molecular weight, in particular further adding an inorganic filler, or it the flat filler, a plate-like filler, columnar fillers or acicular This is remarkable when a filler (fibrous filler) is used in combination.

  As the metal plate, stainless steel plate, SPCC steel plate, aluminum plate, etc. whose surface is roughened by shot blasting, scotch blasting, hairline, dull finish, etc. In general, after solvent degreasing and alkali degreasing, they may be used as they are or after being subjected to a chemical conversion treatment for forming an inorganic or organic rust preventive film. In order to prevent the rubber layer after being crushed for a long time with a high-temperature antifreeze or oil, the above chemical conversion treatment is necessary. In the case of an SPCC steel sheet, a zinc phosphate film and an iron phosphate film are also formed. For gasket material use, a metal plate having a thickness of about 0.1 to 1 mm is used.

An adhesive as a primer is applied on the metal plate. Common adhesives such as silane and epoxy are used as the adhesive, and epoxy adhesive is used to prevent the rubber layer from peeling or blistering after being immersed in a high temperature antifreeze for a long time. . To prevent rubber flow and peeling due to compression under high temperature and high surface, preferably add novolak type phenol resin-containing primer, bisphenol novolac type epoxy resin curing agent (melting point 100-150 ° C) and imidazole compound To be used. Examples of imidazole compounds used as curing catalysts include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzylimidazole, 1-benzyl- 2-methylimidazole, 2,4-diamino-6- [2-methylimidazoline- (1)]-ethyl s-triazine and the like are used.

  Each of these components is used in a proportion of about 30 to 60 parts by weight of a bisphenol novolac type phenol resin and about 0.1 to 5 parts by weight of a curing catalyst for 100 parts by weight of a novolac type epoxy resin. It is done. If the blending ratio of the curing catalyst is less than this, the curing of the resin is slow, the heat resistance is inferior, and the adhesiveness is also lowered. On the other hand, when the curing catalyst is used in a higher ratio, the temporal stability of the organic solvent solution is lowered.

  In the novolac-type phenol resin-containing primer, it is preferable to further mix and use a fluororubber compound. For a primer that does not contain a fluororubber compound, if the drying and baking temperature after applying it to a metal plate that has been subjected to chemical surface treatment is 180 ° C or higher, the primer layer is cured and the rubber coat layer The adhesiveness of the is reduced. For this reason, the drying and baking temperature of the primer must be lowered. However, when a fluororubber compound is blended, good adhesion to the rubber coat layer can be obtained regardless of the drying and baking temperature of the primer. Will be secured.

  The (A) component polyol-crosslinkable fluororubber that forms the fluororubber compound includes vinylidene fluoride, hexafluoropropene, pentafluoropropene, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, par Homopolymers such as fluoroacrylic acid esters, perfluoroalkyl acrylates, perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (propyl vinyl ether), interpolymers or copolymers of these with propylene Preferably, vinylidene fluoride-hexafluoropropene copolymer, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer, tetrafluoroethylene-propylene copolymer, etc. are used. Is, it is possible to actually accept the fluororubber which is commercially available in general is.

  As the component (B) polyol-based vulcanizing agent, for example, 2,2-bis (4-hydroxyphenyl) propane (bisnor A), 2,2-bis (4-hydroxyphenyl) perfluoropropane (bisphenol AF), Bis (4-hydroxyphenyl) sulfone [bisphenol S], 2,2-bis (4-hydroxyphenyl) methane [bisphenol F], bisphenol A-bis (diphenyl phosphate), 4,4'-dihydroxydiphenyl, 2,2 -Bis (4-hydroxyphenyl) butane and the like, and bisphenol A, bisphenol AF and the like are preferably used. These may also be in the form of alkali metal salts or alkaline earth metal salts. These polyol crosslinking agents are generally used at a ratio of about 1 to 10 parts by weight, preferably about 3 to 8 parts by weight, per 100 parts by weight of the fluororubber.

As the component (C) vulcanization accelerator, a quaternary onium salt such as a quaternary ammonium salt or a quaternary phosphonium salt or an equimolar molecular compound of the quaternary phosphonium salt and an active hydrogen-containing aromatic compound is used. Handling phosphonium salts are used. As a quaternary phosphonium salt,
[PR ¹ R ² R ³ R ^{4] +} X ^-
R ^{1 to} R ⁴ : an alkyl group having 1 to 25 carbon atoms, an alkoxyl group, an aryl group, an alkylary
Group, aralkyl group or polyoxyalkylene group, or 2 to 3 of them may form a multiple ring structure with P.
X ⁻ : anions such as Cl ⁻ , Br ⁻ , I ⁻ , HSO ₄ ⁻ , H ₂ PO ₄ ⁻ , RCOO ⁻ , ROSO ₂ ⁻ , CO ₃ ⁻ , specifically tetraphenylphosphonium chloride, benzyltriphenylphosphonium Bromide, benzyltriphenylphosphonium chloride, triphenylmethoxymethylphosphonium chloride, triphenylmethylcarbonylmethylphosphonium chloride, triphenylethoxycarbonylmethylphosphonium chloride, trioctylbenzylphosphonium chloride, trioctylmethylphosphonium chloride, trioctylethylphosphonium acetate, tetra Octyl phosphonium chloride, trioctyl ethyl phosphonium dimethyl phosphate, etc. are used. The quaternary ammonium salt has the general formula [NR ¹ R ² R ³ R ⁴ ] ⁺ X ⁻
Wherein R ^{1 to} R ⁴ and X ⁻ are the same as above, for example, 1-alkylpyridinium salt, 5-aralkyl-1,5-diazabicyclo [4,3,0] -5- Nonenium salts, 8-aralkyl-l, 8-diazabicyclo [5,4,0] -7-undecenium salts and the like are used. These quaternary onium salts are used at a ratio of about 1 to 10 parts by weight, preferably about 2 to 8 parts by weight, per 100 parts by weight of the fluororubber.

The basic magnesium / aluminum / hydroxycarbonate hydrate component (D) has the general formula
MgxAl ₂ (OH) yCO ₃・ mH ₂ O
x: an integer of 4 to 6 or an average value thereof
y: An integer of 12 to 18 or an average value of a mixture thereof, for example, the following is generally used.
Mg ₆ Al ₂ (OH) ₁₆ CO ₃・ 4H ₂ 0
Mg _4.3 Al ₂ (OH) _12.6 CO ₃・ 3.5H ₂ O
Mg _4.5 Al ₂ (OH) ₁₃ CO ₃・ 3.5H ₂ O
Mg ₄ Al ₂ (OH) _13.5 CO ₃・ 3.5H ₂ O
These compounds are added to an aqueous solution of MgCl ₂ and AlCl ₂ with stirring while adding an aqueous NaOH solution and an aqueous Na ₂ CO ₃ solution. The pH is adjusted to around 10 and a white precipitate is taken out and dried to obtain a white powder. Is used. As each metal raw material, hydroxides, oxides, and carbonates may be used in addition to water-soluble salts. Natural minerals and commercially available products similar to basic magnesium, aluminum, hydroxy, carbonate hydrate can also be used. The acid acceptor basic magnesium, aluminum, hydroxy, carbonate hydrate is used in a ratio of about 0.5 to 20 parts by weight, preferably about 1 to 10 parts by weight per 100 parts by weight of the fluororubber, and magnesium oxide is used in combination. In some cases, about 1 to 3 parts by weight are used. If the use ratio is below this range, the vulcanization rate is low and vulcanization is insufficient, while if it is above this range, the vulcanization rate is high and the storage stability of the fluororubber compound or fluororubber coating agent is impaired.

As the component (E), a metal salt such as a Ca salt or Na salt of stearic acid and a heptanoic acid Ca salt are used.

With a small fatty acid metal salts having molecular weight than metallic stearate, poor adhesion to the metal, high temperature, by compression at a high surface pressure, so that peeling of the rubber is observed in the rubber-metal laminate. On the other hand, when a fatty acid metal salt having a molecular weight higher than that of stearic acid metal salt is used, adhesion to the metal immediately after vulcanization is large, and compression of rubber under a high temperature and high surface pressure causes rubber flow in the rubber metal laminate. Be able to .

Therefore, as the component (E), the stearic acid metal salt and the heptanoic acid Ca salt are about 10 to 70% by weight of the former, preferably about 20 to 60% by weight of the latter, and the latter is about 100% by weight. It is used in a proportion of 90-30% by weight, preferably about 80-40% by weight. By using such a fatty acid metal salt in combination, it is possible to achieve both conflicting properties of adhesion to metal and low adhesion to metal immediately after vulcanization, and both of these performances can be improved.

  These fatty acid metal salts are used in a proportion of about 0.2 to 10 parts by weight, preferably about 0.5 to 5 parts by weight, per 100 parts by weight of the fluororubber. If the ratio is less than this, the stickiness of the rubber will increase. On the other hand, if the ratio is greater than this, the adhesion to the metal will be impaired.

  In the fluororubber compound composed of each of the above components, (F) inorganic filling of about 100 parts by weight or less, preferably about 5 to 100 parts by weight, more preferably about 10 to 80 parts by weight, per 100 parts by weight of the fluororubber. It is preferable to use it by adding an agent. The addition of inorganic fillers effectively prevents rubber flow and peeling due to compression under high temperature and high surface pressure, but when used in a proportion higher than this, the rubber hardness becomes very large and rubber elasticity Will also be lost.

  Inorganic fillers having an average particle size of about 1-50 μm, preferably about 5-30 μm, such as carbon black, silica, aluminum silicate, magnesium silicate, calcium silicate, calcium carbonate, magnesium carbonate, iron oxide Aluminum hydroxide or the like is used. If the average particle size is less than this, the hardness of the vulcanized rubber will be increased and the rubber elasticity will be lost. On the other hand, if the average particle size larger than this is used, the surface of the vulcanized rubber will be uneven. It becomes larger and the appearance is damaged. In addition, as the average particle size is smaller, the increase in hardness is larger and the number of blended parts is smaller.

  In addition, it is preferable to use silica in combination with carbon black alone, and lowering the rubber ratio by the combined use of these fillers causes less peeling or blistering on the rubber layer after being immersed in a high temperature antifreeze solution for a long time. Less rubber flow and peeling under more severe conditions due to compression under high surface pressure.

  Further, as the component (G), a flat filler, a plate filler, a columnar filler, a needle having an average diameter of about 1 to 50 μm, preferably about 5 to 30 μm and an aspect ratio of 3 or more, preferably 3 to 15 It is also effective to add a fibrous filler (fibrous filler), and it is particularly preferable to use it together with an inorganic filler. Here, the range of the average particle is limited for the same reason as the average particle size of the inorganic filler, and when the aspect ratio is less than 3, the adhesiveness decreases, and the compression under high temperature and high surface pressure is reduced. This increases the rubber flow. Here, the average diameter of these fillers is the particle size of the filler's ferret diameter measured by the laser light scattering method (interval between both ends of the particle by two parallel lines in an arbitrary fixed direction). The arithmetic mean value obtained from the distribution. The aspect ratio is obtained from (particle area × 1/2) ÷ (thickness) for flat fillers and plate fillers, and (long) for columnar fillers and needle fillers (fibrous fillers). S) ÷ (particle diameter).

Examples of the flat filler, plate filler, and columnar filler include calcium carbonate, aluminum silicate, magnesium silicate, calcium silicate, talc, mica, celite, glass flake, various metal foils, plate-like iron oxide, plate calcium carbonate, as the plate-like aluminum hydroxide, but also needle-shaped filler (fibrous filler), potassium titanate, wollastonite, Dzunotoraito, phosphate fibers, gypsum fibers, dawsonite, aluminum borate, acicular Examples include magnesium hydroxide, acicular calcium carbonate, acicular aluminum silicate, acicular magnesium silicate, glass fiber, carbon fiber, aramid fiber, PVA fiber, alumina fiber, and metal fiber.

  These various fillers have a small increase in hardness even when blended with a large amount of fluororubber, and have the effect of preventing the rubber from flowing due to compression under high temperature and high surface pressure. Approximately 100 weight per 100 parts by weight of fluororubber Or less, preferably about 5 to 100 parts by weight, particularly preferably about 10 to 80 parts by weight. That is, the combined use of these various fillers can reduce the flow and peeling of rubber due to compression under high temperature and high surface pressure. On the other hand, when used at a higher ratio, the rubber hardness becomes very high and the rubber Elasticity will also be lost.

  The fluororubber compound is prepared by kneading using a closed kneader such as an intermix, a kneader, a Banbury mixer, or an open roll. The fluororubber compound is used as a solution of a ketone-alcohol mixed solvent (viscosity of about 200 to 500 cps) with a solid content concentration of about 10 to 40% by weight, preferably about 10 to 30% by weight in the knife coat and roll coater systems. Is preferred. Methyl ethyl ketone and methyl isobutyl ketone are preferably used as the ketone, and methanol is preferably used as the alcohol. In the mixed solvent of both, gelation is accelerated when the proportion of ketone is large, and the stability over time is improved when the proportion of alcohol is increased, but the solubility decreases, so the range of the mixing proportion is Alcohol is used at a ratio of about 10-50% by weight to about 90-50% ketone.

  Further, in the screen printing method or the flow coater method, it is generally used as a solution of a ketone solvent having a high boiling point or a ketone-alcohol mixed solvent. Di-n-propyl ketone, diisobutyl ketone, phorone, isophorone, cyclohexanone, etc. are used as ketones, and n-butanol, amyl alcohol, heptanol, etc. are used as alcohols, and the mixing ratio range is weight ratio. Thus, about 90 to 60% of the ketone is about 10 to 40% of the alcohol.

The organic solvent solution of the fluororubber compound thus prepared is coated with a desired coating thickness on the primer layer on the metal plate surface using a knife coater, flow coater, roll coater, etc. or by screen printing. In the case of pressure vulcanization, about 160-230 ° C., about 20-100 kgf / cm ² (about 1.96-9.8 MPa), about 0.5- Under the condition of 30 minutes, and in the case of using heated air, heat treatment is performed under normal pressure under conditions of about 160 to 230 ° C. and about 5 to 30 minutes, and vulcanized.

  On the vulcanized rubber layer, the main component is a lubricating component such as graphite, PTFE, molybdenum dioxide, carbon black, paraffin wax, and cellulose resin, acrylic resin, polybutadiene resin, urethane resin, etc. are added as a binder to this, A dispersion liquid dispersed in an organic solvent such as toluene or in water is applied to form a non-adhesive layer having a thickness of about 1 to 10 μm, thereby preventing seizure and adhesion.

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

Examples 1-5, Comparative Examples 1-7
Apply a Zr / Al primer (Nihon Parkerizing product) to a stainless steel plate (Nisshin Steel product SUS301, thickness 0.2 mm) degreased with alkali to form a lower primer layer, and then add epoxy phenol resin (Dainippon Ink Chemical). 7% by weight with a methyl ethyl ketone solution of an industrial product (cresol novolac modified epoxy resin) and a bisphenol novolac phenolic resin curing agent (the company's product) and 2-ethyl-4-methylimidazole curing catalyst (Shikoku Chemicals) A primer consisting of 3% by weight of a fluororubber compound and 90% by weight of methyl ethyl ketone having the composition shown in Table 1 is dipped on both sides of a steel plate and heat-treated in an oven at 150 ° C. for about 5 minutes to obtain a thickness on one side. The above primer layer of 2.5 μm was formed on both sides.

On the formed double-sided primer layer, roll a coating solution consisting of 25% by weight of the same fluororubber compound and 75% by weight of methyl ethyl ketone-methanol (weight ratio 80:20) mixed solvent used for forming the upper primer layer. Using a coater, it was coated at a thickness of 20 μm on one side, dried at 60 ° C. for 10 minutes, and then pressure vulcanized at 220 ° C. for 1 minute at 35 kgf / cm ² (3.43 MPa). Thereafter, for the purpose of preventing adhesion of the vulcanized rubber, a toluene dispersion of polyethylene wax to which a polybutadiene resin binder was added was applied and heat-treated at 200 ° C. for 3 minutes to form an adhesion prevention layer having a thickness of 5 μm.
Table 1
Example Comparative Example
Composition (parts by weight) 1 2 3 4 5 1 2 3 4 5 6 7
Fluoro rubber Note 1) 100 100 100 100 100 100 100 100 100 100 100 100
MT carbon black 40 40 40 10 40 40 40 40 40 40 40 40
Silica Note 2) − 20 20 − − − − − − − − −
Calcium carbonate Note 3)---60--------
Calcium silicate Note 4)--10-60-------
Basic Mg ・ Al ・ 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 − − −
Hydroxy carbonate hydrate Note 5)
Magnesium oxide Note 6) 8 8 8 8 8 8 8 8 8 8 8 8
Calcium hydroxide Note 7)----------6 6
Na stearate Note 8)--0.5 0.5 0.5 0.5---0.5 0.5-
Ca stearate Note 9) 0.5 0.5 0.25 0.25 0.25 − − − − 0.25 0.25 −
Heptanoic acid Ca Note 10) 0.5 0.5 0.25 0.25 0.25 − − − − 0.25 0.25 −
Sodium butyrate Note 11)------1-----
Na-melicinate Note 12)-------1----
Vulcanizing agent A Note 13) 6 6 6 6 6 6 6 6 6 6 5 5
Vulcanizing agent B Note 14) 9 9 9 9 9 9 9 9 9 9 2 2
Note 1) DuPont Dow Elastomer Product Viton A-200
Note 2) Japanese silica product, average particle size 20nm
Note 3) Shiraishi Industrial Products, average particle size 50nm
Note 4) Sakai Industrial Products, average diameter 7μm, aspect ratio 5
Note 5) Kyowa Chemical Product DHT-4A
Note 6) Kyowa Chemical Kyowa Mag 30
Note 7) Omi Chemicals product CALDIC # 1000
Note 8), Note 9) Japanese fats and oils Note 10) Wako Pure Chemicals Note 11) Kanto Chemicals Note 12) Wako Pure Chemicals Note 13) DuPont Dow Elastomers Curative # 20
33% organic phosphonium salt, 67% fluororubber (Viton E-45)
Note 14) DuPont Dow Elastomer Product Curative # 30
Bisphenol AF 50% by weight, fluororubber (Viton E-45) 50% by weight

Various evaluations were performed as follows.
Stability evaluation of fluororubber coating solution:
When the coating liquid of the above composition is sealed in a glass bottle with a temperature of 25 ° C. and a humidity of 50% RH, the time until the viscosity is doubled is measured (if this time is within 24 hours, there is a problem in processing. )
Evaluation of adhesion with metal immediately after vulcanization:
Silicone rubber mat (thickness 2 mm) / SUS301 (thickness 0.2 mm) / rubber-metal laminates of those (thickness 0.26 mm) / SUS301 (thickness 0.2 mm) / silicone rubber mat (thickness 2 mm), the pressure Vulcanization under pressure vulcanization conditions, and immediately after vulcanization, evaluate whether there is adhesion between the rubber metal laminate and SUS steel sheet. If there is a problem, it is evaluated as x (in the case of x evaluation, a release agent was applied on SUS301 )
Compression resistance test:
The rubber flows out when the rubber metal laminate is pressed and compressed with a stainless steel convex part at 150 ° C, 1, 2 or 3 tons / cm ² (98, 196 or 294 MPa) for 5 minutes. The condition is evaluated in 5 stages, with 5 points for no metal exposure and almost no rubber flow, 4 for no metal exposure, 4 for low rubber flow, no metal exposure, during rubber flow. (Rubber flow is not large enough to cause metal exposure), with low metal exposure, high rubber flow, rating 2, high metal exposure, high rubber flow with rating 1. Water resistance test:
After immersing the rubber metal laminate in water in a pressure vessel at 150 ° C for 100 hours, a gobang test was conducted according to JIS K5600, and the degree of rubber peeling was evaluated in five stages, with a rubber remaining rate of 100%. 5. Rating 95% or more, rating 4, 85% or more, less than 95%, rating 3, 65% or more, less than 85%, rating 2, less than 65%, rating 1. Oil resistance test:
The rubber metal laminate was immersed in IRM903 oil at 200 ° C for 15 hours, and then a gobang test and evaluation similar to the water resistance test were conducted.

  In these compression resistance test, water resistance test, and oil resistance test, a score of 5 to 3 has no problem in performance, and a score of 2 to 1 has a problem in performance.

The above various evaluation results are shown in the following Table 2.
Table 2
Example Comparative Example
Evaluation item 1 2 3 4 5 1 2 3 4 5 6 7
Coating solution stability 100 100 100 100 100 100 100 100 100 200 15 15
(hrs)
Adhesion evaluation immediately after vulcanization ○ ○ ○ ○ ○ △ ○ × × × ○ ×
Compression resistance test 1 ton 4 5 5 5 5 4 4 3 4 2 4 4
2 tons 4 5 5 4 5 4 2 3 4 1 4 4
3 tons 3 4 5 4 4 3 2 2 3 1 3 3
Water resistance test 3 4 5 3 3 3 2 3 3 2 3 3
Oil resistance test 4 4 5 4 5 4 2 4 4 2 4 4

Claims (6)

(A) fluororubber, (B) polyol vulcanizing agent, (C) quaternary onium salt vulcanization accelerator, (D) basic magnesium, aluminum, hydroxy, carbonate hydrate acid acceptor and (E) A fluororubber coating agent comprising an organic solvent solution of a fluororubber compound containing a fatty acid metal salt in which stearic acid metal salt and heptanoic acid Ca salt are used in combination. (A) 100 parts by weight of component (B) component 1-10 parts by weight, (C) component 1-10 parts by weight, (D) component 0.5-20 parts by weight, stearic acid metal salt and heptanoic acid Ca salt The fluororubber coating agent according to claim 1, wherein a fluororubber compound containing 0.2 to 10 parts by weight of the component (E) used in a ratio of 10 to 70% by weight: 90 to 30% by weight is used. .   The fluororubber coating agent according to claim 2, further comprising (F) a fluororubber compound containing 5 to 100 parts by weight of an inorganic filler.   (G) A fluororubber compound containing 5 to 100 parts by weight of at least one of flat filler, plate filler, columnar filler and needle filler (fibrous filler) is used. 2. The fluororubber coating agent according to 2 or 3.   A rubber metal laminate in which a fluororubber layer is formed on a metal plate using the fluororubber coating agent according to claim 1, 2, 3 or 4. The rubber metal laminate according to claim 5, wherein a fluororubber layer is formed on a fluororubber compound-containing primer layer-forming metal plate.