Patent Application
20170037935
The present invention relates to a chain such as a bush chain and a roller chain which is used in a corrosive atmosphere of acid, alkali, salt water, or the like and in which an alloy coating layer containing zinc is formed on the surface and then a paint film is formed on the alloy coating layer by employing a paint containing zinc and resin.
In the conventional art, for the purpose of corrosion protection of a chain used in a corrosive atmosphere of salt water or the like, the iron-based basis material surface of each component of the chain is coated with a metal such as zinc which is baser than iron or, alternatively, with a metal such as nickel nobler than iron. The former kind of method, i.e., zinc plating, includes electro zinc plating and powder-impact zinc plating. The latter kind of method, i.e., nickel plating, includes electro nickel plating and electroless nickel plating.
Further, in some cases, the sacrificial protection action of zinc and aluminum (the action in which such a metal has a higher ionization tendency than iron and hence is eluted before iron elution so as to suppress iron corrosion) is employed so that a paint film is formed on the surface of an iron-based basis material of each component of the chain by employing a water-based anti-corrosive paint containing zinc, aluminum, and the like as metal pigments.
Patent Document 1 discloses an invention of a component for anti-corrosive chain constructed such that a zinc coating layer is formed on an iron basis material in a non-hydrogen atmosphere and then a water-based anti-corrosive paint containing aluminum powder and silicone resin is bake-coated on the zinc coating layer so that a white-rust preventing bake-coated film is formed.
Patent Document 2 discloses an invention of a chain constructed such that a blasting material composed of zinc-iron alloy is projected onto an iron basis material so that a zinc-iron alloy underlying coating layer is formed and then a water-based anti-corrosive paint containing base metal powder composed mainly of zinc, an organic compound containing a mercapto group and coating the base metal powder, and a nitrate is applied onto the zinc-iron alloy underlying coating layer so that a paint film is formed.
Further, Patent Document 3 discloses an invention of a chain in which a material composed of polyether ether ketone resin is insert-molded on the inner peripheral surface of a bush of the chain such that the axis-directional center part may become thick, so that excellent chemical resistance is achieved and hence initial wear elongation is allowed to be reduced even in an application where cleaning with chemicals is performed and, at the same time, wear resistance is allowed to be improved.
[Patent Document 1] Japanese Patent No. 3122037
[Patent Document 2] Japanese Patent No. 4869349
[Patent Document 3] Japanese Patent Application Laid-Open Publication No. 2010-1914
However, in the case of Patent Document 1, when the chain constituent components having undergone corrosion protection are to be assembled, at the time that a bush is press-fit to the inner plates and a connecting pin is press-fit to the outer plates, paint film spalling easily occurs in the tightened rivet part. Thus, rusting easily begins starting from this position at an early stage and hence the chemical resistance is degraded. Accordingly, repair has been required after assembling of the chain.
Further, the water-based anti-corrosive paint of Patent Document 2 has satisfactory storage stability and the chain also has a satisfactory rust prevention property. However, further improvement in the chemical resistance is required.
Further, in the case of Patent Document 3, the resin material intervenes between the bush and the pin of the chain and hence the wear resistance and the chemical resistance of the sliding part between the bush and the pin are satisfactory. However, there has been a problem that chemical resistance is not obtained in the surfaces of the inner plate and the outer plate of the chain.
The present invention has been devised in view of such situations. An object thereof is to provide a chain in which an alloy coating layer suppressing iron reactions is formed on the surface and hence the paint film formed on the alloy coating layer has satisfactory adhesiveness, high strength, and high uniformity so that repair after assembling is not required and the chemical resistance is maintained satisfactorily.
As a result of earnest research, the present inventors have found that an alloy coating layer containing zinc is formed on the surface of an iron-based basis material of a chain, then a water-based anti-corrosive paint containing zinc and barium sulfate and/or colloidal silica is applied on the alloy coating layer, and then a paint film is formed such that at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened, so that satisfactory chemical resistance and satisfactory adhesiveness are imparted to the chain. As such, the present invention has been achieved.
A chain according to a first embodiment of the present invention is fabricated from an iron-based material, constructed by alternately linking a pair of outer plates and a pair of inner plates, and provided with a paint film formed by employing a water-based anti-corrosive paint, wherein: a zinc-aluminum-magnesium alloy coating layer formed on a surface is provided; the water-based anti-corrosive paint contains zinc and barium sulfate; and the paint film is constructed such that the water-based anti-corrosive paint is applied on the zinc-aluminum-magnesium alloy coating layer and then at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened.
In the chain according to a second embodiment of the present invention, based on the first embodiment, a mass ratio of the barium sulfate to the zinc is 7 or lower.
In the chain according to a third embodiment of the present invention, based on the first or second embodiment, the water-based anti-corrosive paint further contains colloidal silica; and a mass ratio of a solid content of the colloidal silica to a total mass of the zinc and the barium sulfate is 0.04 or lower.
In the chain according to a fourth embodiment of the present invention, based on any one of the first to third embodiments, as for a total mass of the zinc and the barium sulfate or, alternatively, a total mass of the zinc, the barium sulfate, and the solid content of the colloidal silica in a case that the colloidal silica is contained, a mass ratio of the total mass to an entire mass obtained as a sum of the total mass and a mass of a solid content of the resin having been hardened is 0.2 or higher and 0.7 or lower.
A chain according to a fifth embodiment of the present invention is fabricated from an iron-based material, constructed by alternately linking a pair of outer plates and a pair of inner plates, and provided with a paint film formed by employing a water-based anti-corrosive paint, wherein a zinc-aluminum-magnesium alloy coating layer formed on a surface is provided; the water-based anti-corrosive paint contains zinc and colloidal silica; the paint film is constructed such that the water-based anti-corrosive paint is applied on the zinc-aluminum-magnesium alloy coating layer and then at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened; and a mass ratio of a solid content of the colloidal silica to the zinc is 0.02 or lower.
A chain according to a sixth embodiment of the present invention is fabricated from an iron-based material, constructed by alternately linking a pair of outer plates and a pair of inner plates, and provided with a paint film formed by employing a water-based anti-corrosive paint, wherein: a zinc-aluminum-magnesium alloy coating layer formed on a surface is provided; the water-based anti-corrosive paint contains zinc and does not contain barium sulfate and colloidal silica; the paint film is constructed such that the water-based anti-corrosive paint is applied on the zinc-aluminum-magnesium alloy coating layer and then at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened; and a mass ratio of a mass of the zinc to a total mass obtained as a sum of the mass of the zinc and a mass of a solid content of the resin having been hardened is 0.2 or higher and 0.7 or lower.
A chain according to a seventh embodiment of the present invention is fabricated from an iron-based material, constructed by alternately linking a pair of outer plates and a pair of inner plates, and provided with a paint film formed by employing a water-based anti-corrosive paint, a zinc-iron alloy coating layer formed on a surface is provided; the water-based anti-corrosive paint contains zinc serving as a first pigment and a second pigment containing barium sulfate; the paint film is constructed such that the water-based anti-corrosive paint is applied on the zinc-iron alloy coating layer and then at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened; and as for a total mass of the zinc and a solid content of the second pigment, a mass ratio of the total mass to an entire mass obtained as a sum of the total mass and a mass of a solid content of the resin having been hardened is 0.2 or higher and 0.42 or lower.
In the chain according to an eighth embodiment of the present invention, based on any one of the first to seventh embodiments, the water-based anti-corrosive paint further contains: a silane compound whose molecule includes an alkyl group, a phenyl group, or a halo-alkyl group obtained by replacing a part or all of hydrogen atoms with halogen atoms, and a hydrolytic silicon group; and at least one kind of surfactant selected from a group consisting of polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene distyrenated phenyl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and alkyl ether phosphate salt.
In the chain according to a ninth embodiment of the present invention, based on the eighth embodiment, a mass ratio of the silane compound to the zinc is 0.005 or higher and 0.8 or lower.
In the chain according to a tenth embodiment of the present invention, based on the eighth or ninth embodiment, a mass ratio of the surfactant to the zinc is 0.005 or higher and 0.8 or lower.
In the chain according to a eleventh embodiment of the present invention, based on any one of the eighth to tenth embodiments, the water-based anti-corrosive paint further contains a silane coupling agent whose molecule includes: at least one functional group selected from a group consisting of an epoxy group, a methacryloxy group, an acryloxy group, an amino group, and a vinyl group; and a hydrolytic silicon group.
In the chain according to a twelfth embodiment of the present invention, based on the eleventh embodiment, a mass ratio of the silane coupling agent to the zinc is 0.005 or higher and 1 or lower.
In the embodiment, an alloy coating layer containing zinc, aluminum, and magnesium which have ionization tendencies higher than iron and hence are oxidized faster than iron under the presence of an alkaline aqueous solution or the like is formed on the surface of the iron-based basis material of the chain. Thus, iron oxidization is suppressed satisfactorily. Further, in the embodiment, a water-based anti-corrosive paint containing zinc and barium sulfate and/or colloidal silica is applied on the alloy coating layer and then a paint film is formed such that at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened. Since the paint film contains barium sulfate, the paint film strength and the adhesiveness become satisfactory. Further, since the paint film contains colloidal silica, the rust prevention property under the presence of salt water is also improved.
Thus, in the chain according to the embodiment, the adhesiveness of the paint film to the alloy film is satisfactory and the paint film has high strength and high uniformity. Accordingly, at the time of assembling and usage, generation of paint film powder is suppressed and repair after assembling is not required. Further, the chemical resistance is maintained satisfactorily.
In a case that the water-based anti-corrosive paint contains a silane compound and a surfactant, the surfactant causes the silane compound to be affinitive to water so that hydrolysis easily occurs and then the zinc is bonded to the silanol group generated by the hydrolysis so as to be satisfactorily dispersed and stabilized in the paint. Thus, the paint is easily hardened at the time of baking and the paint film is more uniformly formed on the chain.
According to the chain of the present invention, a paint film is formed such that a zinc-aluminum-magnesium alloy coating layer is formed on the surface of the iron-based basis material of the chain, then a water-based anti-corrosive paint containing zinc and barium sulfate and/or colloidal silica is applied on the zinc-aluminum-magnesium alloy coating layer, and then at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened. Thus, the adhesiveness, the strength, and the uniformity of the paint film are satisfactory. Further, satisfactory chemical resistance is maintained for a long term.
Further, in a case that a zinc-iron alloy coating layer is formed on the surface of the iron-based basis material of the chain, when the PWC is adjusted, the chain has satisfactory chemical resistance.
An example of the chain according to the present invention is a bush chain constructed from an iron-based material and including: a pair of inner plates arranged in a manner of being separated from each other; a bush press-fit into bush press-fitting holes of the inner plates; a pair of outer plates arranged on the outer sides of the inner plates and linked to the inner plates in the forward and rearward directions; and a connecting pin press-fit into pin press-fitting holes of the outer plates in a manner of being loosely fit to the inner peripheral surface of the bush. Further, the present invention may be applied to a roller chain constructed such that a roller is further fit loosely to the outer peripheral surfaces of the connecting pin and the bush.
Employable detailed shapes for the inner plate and the outer plate in the chain of the present invention include an elliptical plate and a gourd-shaped plate.
The surface of the above-described constituent component of the chain of the present invention is provided with a zinc-aluminum-magnesium alloy coating layer (a Zn—Al—Mg alloy coating layer). The Zn—Al—Mg alloy coating layer is formed by projecting a blasting material containing Zn—Al—Mg alloy onto the surface (by impact plating) by using a projection apparatus for mechanical plating or the like.
Employable ranges of the composition of the alloy are Al: 1 to 5 mass %, Mg: 5.5 to 15 mass %, and Zn: remaining part. An example of the composition of the blasting material is Al: 3 mass %, Mg: 6 mass %, and Zn and impurities: 91 mass %.
The chain according to the present invention includes a first paint film fabricated by employing a water-based anti-corrosive paint and formed on the Zn—Al—Mg alloy coating layer.
The water-based anti-corrosive paint contains zinc serving as a first pigment.
It is preferable that the zinc is in a powder form. Further, a flake form is more preferable. When a flake form is employed, the specific surface area increases and hence contact of metal powder to each other becomes dense. Thus, in addition to the active anti-corrosiveness of the metal itself, a protection barrier effect (passive anti-corrosiveness) based on the flake form is also obtained. This suppress occurrence of cracks in the paint film.
Further, the zinc may be made into a slurry form by using a water-soluble solvent. Employable water-soluble solvents include a glycol solvent such as propylene glycol and ethylene glycol, an alcoholic solvent such as ethanol and isopropanol, and a glycol ether solvent such as dipropylene glycol monomethyl ether.
In addition to the zinc, the water-based anti-corrosive paint may contain aluminum powder or a powder-form alloy containing: zinc; and aluminum, magnesium, tin, cobalt, manganese, or the like.
The water-based anti-corrosive paint contains such a component that when the paint is applied and baked on the Zn—Al—Mg alloy coating layer, at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened so that a first paint film is formed.
In a case that a urethane resin is hardened so that the first paint film is formed, the water-based anti-corrosive paint contains a polyisocyanate compound and a polyol compound.
Employable polyisocyanate compounds include polyisocyanate compounds described in Japanese Patent Application Laid-Open Publication No. 2014-25062. Specifically, such compounds include: an aliphatic polyisocyanate such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and lysine diisocyanate; a biuret type adduct, an isocyanurate ring adduct, an allophanate type adduct, and a uretdione type adduct of the aliphatic polyisocyanate; an alicyclic diisocyanate such as isophorone diisocyanate, 4,4′-methylene bis(cyclohexyl isocyanate), and methylcyclohexane-2,4- or -2,6-diisocyanate; a biuret type adduct and an isocyanurate ring adduct of the alicyclic diisocyanate; an aromatic diisocyanate compound such as xylylene diisocyanate, tetramethyl xylylene diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate, and 1,4-naphthalene diisocyanate; a biuret type adduct and an isocyanurate ring adduct of aromatic diisocyanate; hydrogenerated MDI and a derivative of hydrogenerated MDI; a urethanated adduct obtained by a reaction of a polyisocyanate compound with the hydroxyl group of a polyol such as ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylol propionic acid, polyalkylene glycol, trimethylolpropane, and hexanetriol at a ratio where the isocyanate group is excessive; and a biuret type adduct or an isocyanurate ring adduct of the urethanated adduct.
The employed polyisocyanate compound may be a blocked polyisocyanate compound obtained by adding a blocking agent to the isocyanate group of the above-described polyisocyanate compound. Employable blocking agents include a blocking agent composed of phenol, lactam, alcohol, ether, oxime, active methylene, mercaptan, acid amide, imide, amine, imidazole, pyrazole, or the like.
Employable polyol compounds include epoxy resins described in Japanese Patent Application Laid-Open Publication No. 2014-19752. Specifically, such compounds include polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, and polycarbonate polyol.
Employable polyester polyol includes: a polyester polyol obtained by a condensation reaction between a dibasic acid and a polyhydric alcohol; and a polycaprolactone obtained by ring opening polymerization of ε-caprolactone performed by employing a polyhydric alcohol or the like.
Employable acrylic polyols include a copolymer between: a single compound or a mixture of ethylenic-unsaturated-bond containing monomers having a hydroxyl group; and a single compound or a mixture of other ethylenic-unsaturated-bond containing monomers allowed to be copolymerized with the above-described one.
Employable polyether polyol includes: a polyether polyol obtained by adding a single compound or a mixture of alkylene oxides to a single compound or a mixture of ployvalent hydroxy compounds under the presence of a strongly basic catalyst; a polyether polyol obtained by a reaction of a multifunctional compound such as an ethylenediamine with an alkylene oxide; and a so-called polymer polyol obtained by polymerization of an acrylamide or the like by employing the above-described polyether as a medium.
Employable polyolefin polyols include polybutadiene, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene having two or more hydroxyl groups.
Employable fluorine polyols include a polyol the molecule of which contains fluorine and an example of which is a copolymer of fluoroolefin, cyclo vinyl ether, hydroxyalkyl vinyl ether, monocarboxylic acid vinyl ester, or the like disclosed in Japanese Patent Application Laid-Open Publications No. S57-34107 and No. S61-275311.
Employable polycarbonate polyols include one obtained by condensation polymerization between a low-molecular-weight carbonate compound and a polyhydric alcohol.
The above-described water-based anti-corrosive paint containing a polyisocyanate compound and a polyol compound is applied on a chain. Then, at the time of baking, the isocyanate group of the polyisocyanate compound and the active hydrogen of the polyol compound react with each other so that hardening occurs. When the blocked polyisocyanate compound is employed, the blocking agent is dissociated and then the isocyanate group having been bonded to the blocking agent reacts with the active hydrogen.
Here, in place of the approach that the polyisocyanate compound and the polyol compound are mixed into the water-based anti-corrosive paint, a urethane resin may be mixed into the water-based anti-corrosive paint from the beginning.
In a case that an epoxy resin is hardened so that the first paint film is formed, the water-based anti-corrosive paint contains the epoxy resin and a curing agent.
Employable epoxy resins include epoxy resins described in Japanese Patent Application Laid-Open Publication No. 2014-19752. Specifically, employable epoxy resins include a novolak type epoxy resin, a glycidyl ether type epoxy resin, a glycol ether type epoxy resin, an epoxy type resin of aliphatic unsaturated compound, an epoxy type fatty acid ester, a ployvalent carboxylate type epoxy resin, an amino glycidyl type epoxy resin, a β-methylepichloro type epoxy resin, a cyclic oxirane type epoxy resin, a halogen type epoxy resin, and a resorcinol type epoxy resin.
Employable curing agents include a curing agent described in Japanese Patent No. 5071602. Specifically, such agents include amine compounds, amide compounds, acid anhydride compounds, and phenol compounds.
Employable amine compounds include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenyl sulfone, isophorone diamine, imidazole, a BF3 amine complex, and a guanidine derivative.
Employable amide compounds include: dicyandiamide; and a polyamide resin synthesized from linolenic acid dimer and ethylenediamine.
Employable acid anhydride compounds include phthalic anhydride, trimellitic anhydride, pyromellitic dianhydride, maleic anhydride, tetrahydrophthalic anhydride, methyl cyclohexene-dicarboxylic anhydride, anhydrous methyl nadic acid, hexahydrophthalic anhydride, and methyl hexahydrophthalic anhydride.
Employable phenol compounds include a polyhydric phenol compound such as phenol novolak resin, cresol novolak resin, aromatic hydrocarbon formaldehyde resin, modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin, naphthol aralkyl resin, trimethylolmethane resin, tetra phenilol ethane resin, naphthol novolak resin, naphthol phenol condensation-copolymerized novolak resin, naphthol cresol condensation-copolymerized novolak resin, biphenyl modified phenol resin, biphenyl modified naphthol resin, aminotriazine modified phenol resin, and alkoxy-group-containing aromatic-ring-modified novolak resin.
Further, the employed curing agent may be the polyisocyanate compound or the blocked polyisocyanate compound described above.
The water-based anti-corrosive paint containing the epoxy resin and the curing agent described above is applied on a chain and then baking is performed. By virtue of this, the epoxy resin is hardened.
In a case that an acrylic resin is hardened so that the first paint film is formed, the water-based anti-corrosive paint contains the acrylic resin.
The acrylic resin is obtained by emulsion polymerization of monomers composed mainly of acrylic monomers performed in an aqueous system by using an emulsifier. The acrylic monomer is a monomer having a (meta)acrylic group. As the monomer employed as the main component, a monomer not containing an active hydrogen group is preferable. On the other hand, for the purpose of stabilization of the emulsion polymerization, it is preferable that a monomer having a hydrophilic group (such as a hydroxyl group, a carboxyl group, and an ether group) is employed together.
Employable acrylic monomers include the following monomers described in Japanese Patent No. 5397946.
Among (meta)acrylic monomers, examples of (meta)acrylic acid alkyl esters include methyl (meta)acrylate, ethyl (meta)acrylate, propyl (meta)acrylate, isopropyl (meta)acrylate, butyl (meta)acrylate, isobutyl (meta)acrylate, s-butyl (meta)acrylate, t-butyl (meta)acrylate, pentyl (meta)acrylate, s-pentyl (meta)acrylate, 1-ethylpropyl (meta)acrylate, 2-methylbutyl (meta)acrylate, isopentyl (meta)acrylate, t-pentyl (meta)acrylate, 3-methylbutyl (meta)acrylate, neopentyl (meta)acrylate, hexyl (meta)acrylate, 2-methylpentyl (meta)acrylate, 4-methylpentyl (meta)acrylate, 2-ethylbutyl (meta)acrylate, cyclopentyl (meta)acrylate, cyclohexyl (meta)acrylate, heptyl (meta)acrylate, 2-heptyl (meta)acrylate, 3-heptyl (meta)acrylate, octyl (meta)acrylate, 2-octyl (meta)acrylate, 2-ethylhexyl (meta)acrylate, isooctyl (meta)acrylate, nonyl (meta)acrylate, 3,3,5-trimethylhexyl (meta)acrylate, decyl (meta)acrylate, undecyl (meta)acrylate, lauryl (meta)acrylate, cetyl (meta)acrylate, stearyl (meta)acrylate, eicosyl (meta)acrylate, docosyl (meta)acrylate, tetracosyl (meta)acrylate, methylcyclohexyl (meta)acrylate, isobornyl (meta)acrylate, norbornyl (meta)acrylate, benzyl (meta)acrylate, and phenethyl (meta)acrylate. Among these, a (meta)acrylic acid alkyl ester whose alkyl group has 1 to 24 carbon atoms is preferable.
As the monomer having a hydrophilic group, the following monomers are employable. Employable monomers having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and 2-acryloyloxy propionic acid.
Employable monomers having a hydroxyl group include a hydroxyl-group containing (meta)acryl monomer such as hydroxyl ethyl (meta)acrylate, 2-hydroxyisopropyl (meta)acrylate, hydroxybutyl (meta)acrylate, ethylene glycol mono(meta)acrylate, glycerol mono-(meta)acrylate, polyethylene glycol mono-(meta)acrylate, and polypropylene glycol mono-(meta)acrylate.
Employable ether-group containing monomers include glycerol monoallyl ether, trimethylolpropane monoallyl ether, and allyl alcohol.
Further, the polymerization may be performed in a state that other monomers having a polymerizable double bond are contained together with the (meta)acrylic monomer. Employable such other monomers include an ester-group containing vinyl monomer, a styrene derivative, and a vinyl ether monomer.
It is preferable that the mass ratio of the zinc mass (in a case that barium sulfate and/or colloidal silica described later are further contained as a second pigment, the mass equal to the zinc mass plus the solid content mass of the second pigment is to be adopted) to the entire mass obtained as the sum of the total mass of the pigments and the solid content of the resin having been hardened is 0.2 or higher and 0.7 or lower. In this case, the chemical resistance and the adhesiveness are satisfactory. It is more preferable that the lower limit of the mass ratio is 0.25. Further, the upper limit of the mass ratio is more preferably 0.68, still more preferably 0.65, and remarkably preferably 0.6.
The water-based anti-corrosive paint may contain a silane compound and a surfactant.
In the silane compound, it is preferable that the molecule includes: an alkyl group, a phenyl group, or a halo-alkyl group obtained by replacing a part or all of hydrogen atoms with halogen atoms; and a hydrolytic silicon group.
Employable hydrolytic silicon groups are not limited to a particular one. However, from the perspective of handling property, an alkoxysilyl group is preferable. Then, from the perspective of reactivity, a methoxysilyl group and an ethoxysilyl group are remarkably preferable.
Employable silane compounds include methyl trimethoxysilane, dimethyl dimethoxysilane, phenyl trimethoxysilane, methyl triethoxysilane, dimethyl diethoxysilane, phenyl triethoxysilane, hexyl trimethoxysilane, hexyl triethoxysilane, decyl trimethoxysilane, and trifluoropropyl trimethoxysilane.
The silane compound is easily hydrolyzed and generates a silanol group. Then, the silanol group is bonded to zinc and hence the zinc is satisfactorily dispersed and stabilized in the paint. At the time of formation of the paint film, the silanol group is bonded also to the lower layer paint film and hence adhesiveness between the paint films is also improved.
From the perspectives of expression of this effect, the in-water dispersibility and stability of the paint, and the storage stability, it is preferable that the mass ratio of the silane compound to zinc (the solid content: in a case that the zinc is prepared in the form of zinc paste, the content of zinc in the zinc paste is to be adopted) is 0.005 or higher and 0.8 or lower. The lower limit of the mass ratio is more preferably 0.02 and still more preferably 0.04. Further, the upper limit of the mass ratio is more preferably 0.6.
This silane compound is different from a later-described silane coupling agent whose molecule includes: at least one functional group selected from a group consisting of an epoxy group, a methacryloxy group, an acryloxy group, an amino group, a mercapto group, and a vinyl group; and a hydrolytic silicon group. That is, the silane compound does not include a functional group and hence gelling of the paint is suppressed.
The water-based anti-corrosive paint may contain a surfactant.
It is preferable that the surfactant is at least one kind selected from a group consisting of polyoxyethylene alkylamine, polyoxyethylene alkyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, and alkyl ether phosphate salt.
The polyoxyethylene alkylamine is expressed by a general formula as in the following formula (1).
Here, a=1, 2, . . .
The polyoxyethylene alkyl ether is expressed by a general formula as in the following formula (2).
RO—(CH2CH2O)n—H (2)
The polyoxyethylene distyrenated phenyl ether is expressed by a general formula as in the following formula (3).
Here, n=1, 2, . . .
The polyoxyethylene sorbitan fatty acid ester is expressed by a general formula as in the following formula (4).
Here, a=1, 2, . . .
The sorbitan fatty acid ester is expressed by a general formula as in the following formula (5).
Here, R=CnH2n+1
When the surfactant is contained, the silane compound easily becomes affinitive to water and hence hydrolysis of the silane compound is accelerated. Then, the generated silanol group is bonded to zinc. Thus, the zinc is satisfactorily dispersed in the water-based anti-corrosive paint so that the storage stability is improved. Since the zinc is satisfactorily dispersed and stabilized in the paint, the paint is easily hardened at the time of baking and, at the same time, a paint film having a uniform composition and a uniform thickness is allowed to be formed without a loss.
When the types and the combination of the surfactants are to be determined, HLB is taken into consideration. However, a preferable range of HLB varies depending on the types and the combination of the surfactants. Thus, surfactants are selected such as to have HLB in accordance with the types and the combination of the surfactants.
From the perspectives of the in-water dispersibility and stability of the paint and the storage stability, it is preferable that the mass ratio of the surfactants to zinc (the solid content: in a case that the zinc is prepared in the form of zinc paste, the content of zinc in the zinc paste is to be adopted) is 0.005 or higher and 0.8 or lower. The lower limit of the mass ratio is more preferably 0.02 and still more preferably 0.04. Further, the upper limit of the mass ratio is more preferably 0.6.
The water-based anti-corrosive paint may contain a silane coupling agent whose molecule includes: at least one functional group selected from a group consisting of an epoxy group, a methacryloxy group, an acryloxy group, an amino group, and a vinyl group; and a hydrolytic silicon group. Employable hydrolytic silicon groups are not limited to a particular one. However, from the perspective of handling property, an alkoxysilyl group is preferable. Then, from the perspective of reactivity, a methoxysilyl group and an ethoxysilyl group are remarkably preferable.
Employable silane coupling agents, in a case that the epoxy group is included as a functional group, include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane, and 3-glycidoxypropyl triethoxysilane.
It is expected that the silane coupling agent is hydrolyzed so that a silanol group is generated and then the silanol group is bonded to zinc so that the zinc is stabilized in the paint. The silanol group is bonded also to the to-be-coated material composed of metal. Further, the paint component is bridged or chemically bonded through the functional group. As a result, the adhesiveness of the paint film is improved.
From the perspectives of the in-water dispersibility and stability of the paint, the storage stability, and expression of satisfactory adhesiveness in the paint film, the mass ratio of the silane coupling agent to zinc is preferably 0.005 or higher and 1 or lower. The lower limit of the mass ratio is more preferably 0.02 and still more preferably 0.12. Further, the upper limit of the mass ratio is more preferably 0.8 and still more preferably 0.6.
The water-based anti-corrosive paint may contain barium sulfate as a second pigment. As the employed barium sulfate, precipitated barium sulfate is preferable.
It is preferable that the mass ratio (BaSO4/Zn) of barium sulfate to zinc is 7 or lower. In this case, the paint film strength and adhesiveness are satisfactory, the chemical resistance is satisfactory, and the concealment property is satisfactory. The lower limit of BaSO4/Zn is more preferably 0.15 and still more preferably 0.3. The upper limit of BaSO4/Zn is more preferably 6. Since the barium sulfate is contained, the rust prevention property under the presence of salt water also becomes satisfactory.
In addition to the barium sulfate, the water-based anti-corrosive paint may contain colloidal silica as a second pigment. It is preferable that the mass ratio [(solid content of colloidal silica)/(Zn+BaSO4)] of the solid content of the colloidal silica to the total mass of zinc and barium sulfate is 0.04 or lower. In this case, the chemical resistance is satisfactory and the storage stability of the water-based anti-corrosive paint is satisfactory. The upper limit of (solid content of colloidal silica)/(Zn+BaSO4) is more preferably 0.02. Since the colloidal silica is contained, the rust prevention property under the presence of salt water also becomes satisfactory.
When the water-based anti-corrosive paint does not contain barium sulfate and contains colloidal silica alone, it is preferable that the mass ratio [(solid content of colloidal silica)/(Zn)] of the solid content of the colloidal silica to zinc is 0.02 or lower. In this case, the chemical resistance is satisfactory and the storage stability of the water-based anti-corrosive paint is satisfactory. The upper limit of the mass ratio is more preferably 0.01.
In the water-based anti-corrosive paint, allowed to be added are: a water-soluble solvent; and additives for paint such as a wetting agent, a wetting and dispersing additive, an antifoaming agent, thickener, and a pH adjuster. Employable water-soluble solvents include a glycol solvent such as propylene glycol and ethylene glycol, an alcoholic solvent such as ethanol and isopropanol, and a glycol ether solvent such as dipropylene glycol monomethyl ether.
Employable additives for paint include: a wetting and dispersing additive composed of polycarboxylic acid or the like; a wetting agent composed of organic phosphate ester, diester sulfosuccinate such as sodium bistridecyl sulfosuccinate, or the like; an antifoaming agent composed of a silicone or acrylic substance; and a thickener composed of an ether of hydroxyethylcellulose, methylcellulose, methyl hydroxypropylcellulose, ethyl hydroxyethylcellulose, or methylethylcellulose, and a mixture of these substances.
The water-based anti-corrosive paint is applied on the Zn—Al—Mg alloy coating layer by dipping treatment such as immersion drain (dip drain) and immersion rotation (dip spin), by brushing, by spraying, or by another method.
It is preferable that the paint of the present invention is baked at 180 degrees C. or lower for 30 to 40 minutes. In this case, hardness degradation does not occur in the chain constituent components and hence degradation in the chain strength and in the chain lifetime is suppressed.
The paint of the present invention may be applied plural times onto the Zn—Al—Mg alloy coating layer.
From the perspectives of expression of satisfactory corrosion resistance and the cost, it is preferable that the coating is performed such that the amount of application may become 5 to 400 mg/dm2 and the total film thickness of the paint films may become 1 to 30 μm. Then, in a case that the first paint film and a second paint film (a paint film formed on the first paint film by using the paint) are formed on the to-be-coated material, it is preferable that the total film thickness of the two paint films is 5 to 30 μm and the amount of application is 50 to 400 mg/dm2.
The chain according to the present invention may be such that the zinc-iron alloy coating layer (the Zn—Fe alloy coating layer) is formed on the surface, then the water-based anti-corrosive paint containing zinc serving as a first pigment and a second pigment containing barium sulfate (colloidal silica may further be contained as the second pigment) is applied on the zinc-iron alloy coating layer, and then at the time of baking, at least one kind of resin selected from a group consisting of urethane resin, epoxy resin, and acrylic resin is hardened so that the first paint film is formed. The mass ratio of the total mass of the solid contents of the first pigment and the second pigment to the entire mass obtained as the sum of the total mass and the solid content of the resin having been hardened is 0.2 or higher and 0.42 or lower. In this case, the chemical resistance and the adhesiveness are satisfactory. The upper limit of the mass ratio is preferably 0.4.
The water-based anti-corrosive paint fabricated as described above has satisfactory storage stability. Then, in the chain of the present invention in which the Zn—Al—Mg alloy coating layer or the Zn—Fe alloy coating layer is formed on the surface of the iron-based basis material and then a paint film is formed on the Zn—Al—Mg alloy coating layer or the Zn—Fe alloy coating layer by employing the water-based anti-corrosive paint, the adhesiveness of the paint film is satisfactory and the chemical resistance is maintained satisfactorily for a long term.
Examples and comparison examples of the present invention are described below in detail. However, the present invention is not limited to these examples.
In accordance with the blending quantity (expressed in mass part) in the following Tables 1 to 3, blended were: zinc flakes (“STANDART (registered tradename) ZINC FLAKE AT” fabricated by ECKART); precipitated barium sulfate (“B-35” fabricated by Sakai Chemical Industry Co., Ltd.); colloidal silica (“PL-3-D” fabricated by Fuso Chemical Co., Ltd.); polyoxyethylene alkyl ether; n-hexyl trimethoxysilane; a wetting and dispersing additive; a polyol compound; a polyisocyanate compound; water; propylene glycol; a silicone-based antifoaming agent (“BYK018” fabricated by BYK Japan KK); and a wetting agent. By this method, the paint of Blend Examples 1 to 35 was obtained.
Tables 1 to 3 list precipitated barium sulfate/zinc flakes (expressed as BaSO4/Zn, hereinafter), [(solid content of colloidal silica)]/[zinc flakes+precipitated barium sulfate] [%] [expressed as colloidal silica/(zinc+barium sulfate) in the tables], and PWC (Pigment Weight Concentration) [%].
The PWC is expressed by the mass ratio between [zinc flakes+(precipitated barium sulfate) and/or (solid content of colloidal silica)] and [zinc flakes+(precipitated barium sulfate) and/or (solid content of colloidal silica)+(the mass of the hardened material (the mass of the solid content of the resin) after the resin has been hardened)] in the inside of the paint film having been formed.
As illustrated in
The surface of each of the inner plate 11, the bush 12, the outer plate 13, the connecting pin 14, and the roller 15 is provided with: a Zn—Al—Mg alloy coating layer 17; a first paint film 18 fabricated by employing the water-based anti-corrosive paint; and a second paint film 19 formed by employing the water-based anti-corrosive paint.
A blasting material composed of Zn—Al—Mg alloy (“ZR#50S” fabricated by Dowa IP Creation Co., Ltd.) was projected onto the surface of the constituent component (the inner plate 11, the bush 12, the outer plate 13, the connecting pin 14, or the roller 15) of the chain 10 so that the Zn—Al—Mg alloy coating layer 17 was formed. Then, the water-based anti-corrosive paint of Blend Example 1 of Table 1 given above was applied on the surface of the Zn—Al—Mg alloy coating layer 17 by a dip spin method and then baked at 180 degrees C. for 40 minutes so that the first paint film 18 having a thickness of 5 μm was formed. Further, the water-based anti-corrosive paint of Blend Example 1 was applied on the surface of the first paint film 18 by a dip spin method and then baked at 180 degrees C. for 40 minutes so that the second paint film 19 having a thickness of 3 μm was formed.
By this method, the chain 10 according to Example 1 was obtained. The configurations of the coating layer and the paint film are listed in the following Table 4. In the following Table 4, the “first coating layer” indicates the Zn—Al—Mg alloy coating layer.
Similarly to Example 1, the coating layer and the paint film having the configurations listed in Table 4 given above and Table 5 given below were formed so that the chain of each of Examples 2 to 28 was fabricated.
A blasting material composed of Zn—Fe alloy was projected onto the surface of the chain so that the Zn—Fe alloy coating layer was formed. Then, the water-based anti-corrosive paint of the blend example listed in Table 5 given above was applied twice on the Zn—Fe alloy coating layer so that the chain of each of Examples 29 to 32 was fabricated. In Table 5, the “second coating layer” indicates the Zn—Fe alloy coating layer.
The Zn—Fe alloy coating layer (the second coating layer) was formed on the surface of the chain and then the water-based anti-corrosive paint of each blend example listed in the following Tables 6 and 7 was applied twice on the second coating layer so that the chain of each of Comparison Examples 1 to 31 was fabricated.
The Zn—Al—Mg alloy coating layer (the first coating layer) was formed on the surface of the chain and then the water-based anti-corrosive paint of each blend example listed in Tables 7 given above and Table 8 given below was applied twice on the first coating layer so that the chain of each of Comparison Examples 32 to 38 was fabricated.
In the chain of Comparison Example 39, the surface is not provided with the alloy coating layer and the paint film.
The Zn—Fe alloy coating layer (the second coating layer) was formed on the surface of the chain. No paint film was formed.
The Zn—Al—Mg alloy coating layer (the first coating layer) was formed on the surface of the chain. No paint film was formed.
Evaluation of the concealment property, the adhesiveness, and the chemical resistance was performed on the chains of the examples and the comparison examples. The evaluation method was as follows.
[Evaluation of Concealment Property]
Whether the underlying coating layer was visually seen was evaluated by visual inspection. Evaluation was as follows.
∘ . . . Underlying layer is not transparent
Δ . . . Underlying layer is somewhat transparent
x . . . Underlying layer is transparent
[Chemical Resistance Test]
Chemical resistance test was performed on the chains of the examples and the comparison examples. In the test, the chain was immersed in each chemical and then the state was checked with time. The presence or absence of rust occurrence or paint-film spalling occurrence was checked at each of the following time points. Evaluation and the elapsed time were as follows.
A . . . 3000 hours
B . . . 2000 hours
C . . . 1000 hours
D . . . 700 hours
E . . . 300 hours
F . . . 100 hours
As described above, in the chain of each of Examples 1 to 28, the Zn—Al—Mg alloy coating layer has been formed as an underlying coating layer. Further, in the chain of each of Comparison Examples 1 to 31, the Zn—Fe alloy coating layer has been formed as an underlying coating layer. As seen from Tables 4 to 8, in the cases that the paint film employing the same water-based anti-corrosive paint was formed on the underlying coating layer, the chemical resistance was remarkably improved in the chain of example than in the chain of comparison example.
As seen from Comparison Examples 39 to 41, in a case that the alloy coating layer and the paint film were not formed or, alternatively, in a case that the first coating layer or the second coating layer was formed but the paint film was not formed, the chemical resistance is remarkably unsatisfactory.
In Example 25 where the PWC is 25%, the chemical resistance is remarkably satisfactory. When the PWC exceeds 70, it has been recognized that the adhesiveness is somewhat degraded. Thus, it is preferable that the PWC is 20% or higher and 70% or lower. The upper limit of the PWC is more preferably 68%, still more preferably 65%, remarkably preferably 60%, and most preferably 40%.
When the water-based anti-corrosive paint contains barium sulfate, the chemical resistance is more satisfactory. As seen from Examples 18 and 19 and Comparison Examples 25 and 26, when BaSO4/Zn is 7.3, that is, exceeds 7, the concealment property is somewhat degraded. Thus, it is preferable that BaSO4/Zn is 7 or lower. The lower limit of BaSO4/Zn is more preferably 0.15 and still more preferably 0.3. The upper limit of BaSO4/Zn is more preferably 6.
When the water-based anti-corrosive paint contains the colloidal silica alone, it is preferable that the mass ratio [(solid content of colloidal silica)/(Zn)] of the solid content of the colloidal silica to zinc is 2% or lower. The upper limit of the mass ratio is more preferably 1%.
When the water-based anti-corrosive paint contains barium sulfate and the colloidal silica, it is preferable that the mass ratio [(solid content of colloidal silica)/(Zn+BaSO4)] of the solid content of the colloidal silica to the total mass of zinc and barium sulfate is 4% or lower. The upper limit of (solid content of colloidal silica)/(Zn+BaSO4) is more preferably 2%.
In the case of a chain the zinc-iron alloy coating layer (the Zn—Fe alloy coating layer) is formed on the surface, it is recognized that when the PWC is 20% or higher and 42% or lower, the chemical resistance is satisfactory. The upper limit of the PWC is preferably 40%.
As recognized from the description given above, the water-based anti-corrosive paint according to the embodiment of the present invention has satisfactory storage stability. Further, in the chain according to the examples of the present invention, the adhesiveness and the concealment property of the paint film are satisfactory and the chemical resistance is satisfactory.
The following description is given for the results of evaluation of in-water stability of the water-based anti-corrosive paint employed in the paint film of the chain of the present invention in a case that the blend of the silane compound, the surfactant, and the silane coupling agent was changed.
In accordance with the blending quantity (expressed in mass part) in the following Table 9, blended were: zinc flakes (“STANDART (registered tradename) ZINC FLAKE AT”); polyoxyethylene alkyl ether serving as a surfactant; n-hexyl trimethoxysilane serving as a silane compound; a wetting and dispersing additive; and water. By this method, the paint of each of Blend Examples A to G was obtained.
Table 9 lists: polyoxyethylene alkyl ether (surfactant)/zinc [%]; n-hexyl trimethoxysilane (silane compound)/zinc [%]; and the results of evaluation of the in-water stability and the storage stability.
As for the in-water stability, the paint was prepared and then left at room temperature for three days. Then, the presence or absence of gas generation was checked. Evaluation was as follows.
∘: Without gas generation
Δ: Very slight gas generation
x: With gas generation
As for the storage stability, the paint was left at 40 degrees C. The following evaluation was employed.
∘: Gelling in 3 days
Δ: Gelling in 1 day
x: Gelling in 3 hours
-: Not evaluated
In accordance with the blending quantity (expressed in mass part) of the following Table 10, blended were: zinc flakes “STANDART (registered tradename) ZINC FLAKE AT”, polyoxyethylene alkyl ether serving as a surfactant, n-hexyl trimethoxysilane serving as a silane compound, a wetting and dispersing additive, 3-glycidoxypropyl trimethoxysilane serving as a silane coupling agent, acetic acid, and water. By this method, the paint of each of Blend Examples H to L was obtained.
Table 10 lists: polyoxyethylene alkyl ether (surfactant)/zinc [%]; n-hexyl trimethoxysilane (silane compound)/zinc [%]; 3-glycidoxypropyl trimethoxysilane (silane coupling agent)/zinc [%]; and the results of evaluation of the in-water stability and the storage stability.
In accordance with the blending quantity (expressed in mass part) in the following Table 11, blended were: zinc flakes (“STANDART (registered tradename) ZINC FLAKE AT”); polyoxyethylene alkyl ether serving as a surfactant, n-hexyl trimethoxysilane serving as a silane compound; a wetting and dispersing additive; and water. By this method the paint of each of Blend Examples M, N P, Q, and R was obtained.
Similarly to Table 9, Table 11 lists: polyoxyethylene alkyl ether (surfactant)/zinc [%]; n-hexyl trimethoxysilane (silane compound)/zinc PA; and the results of evaluation of the in-water stability and the storage stability.
As seen from Blend Examples M N, F, Q, and R, the in-water stability was unsatisfactory in each of the case that the paint does not contain the surfactant and the silane compound, the case that any one of the surfactant and the silane compound is contained by 10% relative to zinc, the case that the surfactant and the silane compound are contained by 0.4% each relative to zinc, and the case that the surfactant and the silane compound are contained by 100% each relative to zinc.
As seen from comparison between Blend Examples A to G and Blend Examples M, N, P, Q, and R, the in-water stability and the storage stability were satisfactory in a case that both of the mass ratio of the surfactant to zinc and the mass ratio of the silane compound to zinc are 0.5% or higher and 80% or lower. The lower limit for the mass ratio of the surfactant to zinc and the mass ratio of the silane compound to zinc is preferably 2% and more preferably 4%. The upper limit is preferably 60%.
As seen from Blend Examples H to L, when the paint further contains the silane coupling agent, the in-water stability becomes more satisfactory.
As seen from comparison between Blend Examples A to L and Blend Examples M, N, P, Q, and R, it is preferable that the mass ratio of the silane coupling agent to zinc is 0.5% or higher and 100% or lower. The lower limit of the mass ratio is more preferably 2% and still more preferably 12%. Further, the upper limit of the mass ratio is more preferably 80% and still more preferably 60%.
As described above, it has been recognized that when the water-based anti-corrosive paint contains the silane compound and the surfactant or, alternatively, when the water-based anti-corrosive paint contains the silane coupling agent in addition to these, the in-water stability and the storage stability are satisfactory. Then, the zinc bonded to the silanol group is satisfactorily dispersed in the paint. Thus, at the time that the paint is applied on the surface of the chain and then baked, the paint is easily hardened and, further, a paint film is allowed to be uniformly formed on the to-be-coated material. Thus, it is expected that in a case that the chain is fabricated from an iron-based material, the sacrificial protection action of zinc is uniformly obtained in the plane directions of the paint film and, further, the chemical resistance of the chain becomes more satisfactory.
The embodiment disclosed above is to be recognized as illustrative and not restrictive at all points. The scope of the present invention is not limited to the description given above and is intended to include the contents equivalent to the spirit of the claims and all changes within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-091801 | Apr 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/054237 | 2/17/2015 | WO | 00 |
