JP7429660B2 - Corrosion prevention method for bolts and nuts - Google Patents

Description

The present invention relates to a method for preventing corrosion of bolts and nuts.

2. Description of the Related Art Conventionally, methods of connecting members using bolts and nuts have been adopted in various structures. Generally, when a bolt and a nut are connected, the threaded portion of the bolt and the nut protrude from the joint surface, and are therefore easily exposed to wind and rain, resulting in a problem in that they are susceptible to rust. As a countermeasure against corrosion of bolts and nuts, a method of applying anticorrosive coating to the bolts and nuts has been used. However, since bolts and nuts have a complicated structure, there is a problem in that rainwater that has entered through the gaps is difficult to escape and the anticorrosion effect is lost in a short period of time. Therefore, as an anti-corrosion measure for bolts and nuts in place of anti-corrosion coating, a method is known in which the joints of bolts and nuts are covered with a resin anti-corrosion member (cap) (see, for example, Patent Document 1 and Patent Document 2). ).

Japanese Unexamined Patent Publication No. 2-138488 Patent No. 5085798

However, such a conventional method requires an operator to attach a corrosion-proofing member to each joint of bolts and nuts. For example, when a large number of bolts and nuts are used at one location, such as in a bridge, there is a problem in that the work of installing the anticorrosion member by a worker becomes complicated. Furthermore, depending on the arrangement of the bolt-and-nut joint in the structure, there is a risk that the corrosion-proofing member may come off just by covering the joint. For this reason, the operator is further required to put a filler into the anticorrosive member, apply an adhesive to the anticorrosive member, etc. before covering the joint. Therefore, in the conventional method as described above, there is a possibility that the installation work of the anti-corrosion member takes a huge amount of time and requires a large number of workers.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a corrosion-proofing method for bolts and nuts that shortens construction time and reduces work burden.

(1) A method for preventing corrosion of bolts and nuts according to an embodiment of the present invention for achieving the above-mentioned object is a method for preventing corrosion of bolts and nuts that protrudes from the object among the metal bolts and metal nuts used for fastening the object to be fastened. A covering step of covering the portion with an uncured rubber sheet, removing air between the rubber sheet and the object to be fastened, and deforming the rubber sheet so as to follow the curved surface of the portion protruding from the object to be fastened. and a curing step of curing the rubber sheet.
(2) In the bolt/nut corrosion prevention method according to another embodiment, it is preferable that the degassing step includes contacting at least the tip of the leg of the bolt that protrudes from the object to be fastened, and protruding from the object to be fastened. The rubber sheet may be deformed so as to follow the curved surface of the curved portion.
(3) In the bolt/nut corrosion prevention method according to another embodiment, it is preferable that a frame body made of a rubber-like elastic body that can be brought into close contact with the object to be fastened be configured to surround at least the fastening portion by the bolt and the nut. The rubber sheet may further include a step of arranging the rubber sheet, and the degassing step may deform the rubber sheet so as to come into close contact with at least the leg end of the bolt protruding from the object to be fastened and the frame.
(4) In the bolt/nut corrosion prevention method according to another embodiment, the rubber sheet may preferably have a plasticity in the range of 100 to 200.
(5) In the bolt/nut corrosion prevention method according to another embodiment, preferably, the rubber sheet may be a silicone rubber sheet.
(6) In the bolt/nut corrosion prevention method according to another embodiment, preferably, the rubber sheet may be a condensation reaction type silicone rubber sheet.

According to the present invention, it is possible to provide a method for preventing corrosion of bolts and nuts, which shortens construction time and reduces work burden.

FIG. 1 shows a plan view of a corrosion-resistant structure in which the bolt and nut corrosion prevention method according to the first embodiment is applied to bolts and nuts used for fastening objects to be fastened. FIG. 2 shows a cross-sectional view taken along line AA of the plan view of FIG. FIG. 3 shows a flowchart of the main steps of the bolt/nut corrosion prevention method according to the first embodiment. FIG. 4 shows a diagram for explaining the anticorrosion method for bolts and nuts according to the first embodiment. FIG. 5 shows a photograph of an example of the state after the degassing step of the anticorrosion method for bolts and nuts according to the first embodiment. FIG. 6 shows a partially enlarged photograph of an example of the state after the hardening process of the anticorrosion method for bolts and nuts according to the first embodiment. FIG. 7 is a plan view of a corrosion-resistant structure in which the bolt and nut corrosion prevention method according to the second embodiment is applied to bolts and nuts used for fastening objects to be fastened. FIG. 8 shows a sectional view taken along line BB of the plan view of FIG. FIG. 9 shows a flowchart of the main steps of the bolt/nut corrosion prevention method according to the second embodiment. FIG. 10 shows a diagram for explaining the anticorrosion method for bolts and nuts according to the second embodiment. FIG. 11 shows a diagram for explaining the anticorrosion method for bolts and nuts according to the second embodiment. FIG. 12 shows a photograph of an example of a corrosion-resistant structure in which the bolt and nut corrosion prevention method according to the first embodiment is applied to bolts and nuts used for fastening objects to be fastened.

Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below do not limit the claimed invention. Furthermore, not all of the elements and combinations thereof described in the embodiments are essential to the solution of the present invention.

(First embodiment)
1. Configuration of Corrosion-Proof Structure FIG. 1 shows a plan view of a corrosion-proof structure in which the bolt and nut corrosion prevention method according to the first embodiment is applied to bolts and nuts used for fastening objects to be fastened. . FIG. 2 shows a cross-sectional view taken along line AA of the plan view of FIG.

The anticorrosion structure 1 is a structure in which the bolt and nut anticorrosion method according to the first embodiment is applied to the bolts 20 and nuts 30 used to fasten the objects 50 and 51. The anti-corrosion structure 1 includes objects 50 and 51 to be fastened, metal bolts 20 and metal nuts 30 that fasten the objects 50 and 51, and bolts 20 and nuts 30 from the objects 50 and 51 to be fastened. An anti-corrosion member 10 is provided to cover the protruding portion. Here, metal means any metal that may rust, such as iron and iron-based alloys (including SUS), without any particular restrictions. The objects to be fastened are, for example, structures fastened with bolts 20 and nuts 30, such as bridges, steel towers, buildings, factories, various buildings such as houses, construction machines, and processing machines. In this embodiment, two plate-like members are illustrated as objects 50 and 51 to be fastened. The anti-corrosion structure 1 preferably includes a washer 40 between the objects 50, 51 and the nut 30. Further, the anti-corrosion structure 1 preferably includes a washer 40 between the objects 50 and 51 to be fastened and the head 21 of the bolt 20. The anti-corrosion structure 1 may not include the washer 40, or may include the washer 40 between the fastened objects 50, 51 and either the nut 30 or the head 21.

In this embodiment, the anti-corrosion structure 1 includes four sets of bolts 20 and nuts 30 (see FIG. 1). However, in the anti-corrosion structure 1, the number of bolts 20 and nuts 30 is not particularly limited as long as the objects 50, 51 are fastened together by at least one set of bolts 20 and nuts 30. In this embodiment, the anti-corrosion member 10 covers the leg portions 22 of the bolt 20 and the nut 30 that protrude from the objects 50, 51 to be fastened (see FIG. 2). However, the anti-corrosion member 10 may cover the head 21 side of the bolt 20 protruding from the objects 50, 51 to be fastened. Further, in cases such as when the tip of the leg portion 22 of the bolt 20 does not protrude from the nut 30, the anticorrosive member 10 may cover only the nut 30.

The anticorrosion member 10 is a member made of rubber that is cured after an uncured rubber sheet 80 (see FIG. 4) is covered and deformed. The rubber sheet in an uncured state also includes a semi-cured state. Hereinafter, the uncured rubber sheet 80 will also be referred to as an uncured rubber sheet 80, an uncured rubber sheet 80, or simply a rubber sheet 80. Rubber members include thermosetting elastomers such as silicone rubber, urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, nitrile rubber (NBR) or styrene-butadiene rubber (SBR); urethane-based and ester-based It is preferable to use thermoplastic elastomers such as , styrene-based, olefin-based, butadiene-based, fluorine-based, etc., or composites thereof. Particularly suitable is silicone rubber, which has excellent UV resistance, ozone resistance, cold resistance, and heat resistance. The silicone rubber constituting the anti-corrosion member 10 will be described in detail below.

(1) Silicone Rubber Silicone rubber is a rubber-like elastic body having a siloxane bond (-Si-O-Si) as its main skeleton. The silicone rubber that can be used in this embodiment may be of any curing type, such as addition curing type, condensation reaction type, UV curing type, electron beam curing type, etc., and in particular, condensation reaction type silicone rubber. is preferable. Silicone rubber is a rubber-like elastic body obtained by curing a curable organopolysiloxane composition (silicone rubber compound) containing organopolysiloxane as a main ingredient. Here, the term "base agent" refers to the agent that is present in the largest proportion by mass among the components constituting the curable organopolysiloxane composition. The organopolysiloxane is preferably contained in the curable organopolysiloxane composition in an amount of 50% by mass or more, but it may be contained in an amount of less than 50% by mass as long as it is a main ingredient. Examples of addition-curable and condensation reaction-type curable organopolysiloxane compositions will be described below as silicone rubber compounds that are raw materials for silicone rubber before curing.

(addition curing type)
The addition-curable curable organopolysiloxane composition may also be referred to as an addition-curable curable silicone composition or an addition-curable curable silicone rubber composition. The addition-curable curable organopolysiloxane composition can be mainly composed of, for example, the following components.

(1-1) Organopolysiloxane Organopolysiloxane is the main ingredient of an addition-curable curable organopolysiloxane composition, and has an average of two or more alkenyl groups in one molecule. The organopolysiloxane is a base polymer of an addition-curable curable organopolysiloxane composition, and is represented by the following average composition formula (I).
R ³ _a SiO _(4-a)/2 ...(I)
In formula (I), R ³ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, which are the same or different from each other, and a is 1. It is a positive number in the range of 5 to 2.8, preferably 1.8 to 2.5, more preferably 1.95 to 2.05.

Examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, hexenyl and heptenyl. Among these, it is preferable to use a vinyl group. In addition, examples of organic groups bonded to silicon atoms other than alkenyl groups in this component include alkyl groups (methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, etc.), aryl groups (phenyl group, etc.) , tolyl group, xylyl group, etc.), and halogenated alkyl groups (3-chloropropyl group, 3,3,3-trifluoropropyl group, etc.). Among these, it is preferable to use a methyl group. Examples of the molecular structure of this component include linear, partially branched linear, branched, network, and dendritic.

The organopolysiloxane of this component includes, for example, polydimethylsiloxane with dimethylvinylsiloxy groups endblocked at both molecular chain ends, dimethylsiloxane/methylvinylsiloxane copolymer endblocked with dimethylvinylsiloxy groups at both molecular end ends, and trimethylsiloxy group at both molecular end ends. Blocked dimethylsiloxane/methylvinylsiloxane copolymer, siloxane units represented by (CH ₃ ) ₃ SiO _1/2 , siloxane units represented by (CH ₃ ) ₂ (CH ₂ =CH)SiO _1/2 , and SiO _4/ Organopolysiloxanes consisting of siloxane units represented by ₂ , at least a part of the methyl groups of these organopolysiloxanes are converted into alkyl groups (ethyl groups, propyl groups, etc.), aryl groups (phenyl groups, tolyl groups, etc.), halogenated Organopolysiloxanes substituted with substituents selected from alkyl groups (3,3,3-trifluoropropyl groups, etc.), at least a portion of the vinyl groups of these organopolysiloxanes are substituted with alkenyl groups (allyl groups, propenyl groups, etc.) Organopolysiloxanes substituted with , and mixtures of two or more of these organopolysiloxanes can be used.

(1-2) Hydrogenated organopolysiloxane Hydrogenated organopolysiloxane acts as a curing agent for addition-curable curable organopolysiloxane compositions, and has an average of two or more silicon atom bonds in one molecule. Contains hydrogen. Hydrogenated organopolysiloxanes are also referred to as organohydrogenpolysiloxanes. The hydrogenated organopolysiloxane is represented by the following average composition formula (II), and contains at least 2, preferably 3 or more, more preferably 3 to 100, and even more preferably 4 to 50 silicon atoms in one molecule. Those having a bonded hydrogen atom (SiH group) are preferably used.
R ⁴ _b H _c SiO _(4-b-c)/2 ...(II)
In formula (II), R ⁴ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms, which are the same or different from each other. Furthermore, b is a positive number satisfying 0.7 to 2.1, c is 0.001 to 1.0, and b+c is a positive number satisfying 0.8 to 3.0.

Examples of organic groups bonded to silicon in this component include alkyl groups (methyl, ethyl, propyl, butyl, pentyl, hexyl, etc.), aryl groups (phenyl, tolyl, xylyl, etc.) ), halogenated alkyl groups (3-chloropropyl group, 3,3,3-trifluoropropyl group, etc.). Among the above, it is preferable to use a methyl group. Examples of the molecular structure of this component include linear, partially branched linear, branched, network, and dendritic.

The hydrogenated organopolysiloxane of this component includes, for example, polydimethylsiloxane with dimethylhydrogensiloxy groups blocked at both molecular chain ends, polymethylhydrogensiloxane with trimethylsiloxy groups blocked on both molecular chain ends, and dimethylsiloxane with trimethylsiloxy groups blocked on both molecular chain ends.・Methylhydrogensiloxane copolymer, cyclic polymethylhydrogensiloxane, organopolysiloxane consisting of a siloxane unit represented by (CH ₃ ) ₂ HSiO _1/2 and a siloxane unit represented by SiO _4/2 ; At least a portion of the methyl groups of polysiloxane are replaced with alkyl groups (ethyl, propyl, etc.), aryl groups (phenyl, tolyl, etc.), or halogenated alkyl groups (3,3,3-trifluoropropyl, etc.). Substituted organopolysiloxanes and mixtures of two or more of these organopolysiloxanes can be used. Among these, organopolysiloxanes that have silicon-bonded hydrogen atoms only at both ends of the molecular chain and those that have silicon-bonded hydrogen atoms on the side chains of the molecular chain have been found to improve the mechanical properties (especially elongation) of the resulting cured product. Preference is given to using mixtures with organopolysiloxanes.

The content of this component in the addition-curable curable organopolysiloxane composition is such that the molar ratio of silicon-bonded hydrogen atoms in this component to the alkenyl group in component (1-1) is in the range of 0.01 to 20. The amount is preferably within the range of 0.1 to 10, and more preferably the amount is within the range of 0.1 to 5. The reason for setting the above range is that when the content of this component is above the lower limit of the above range, the silicone rubber tends to be sufficiently cured.On the other hand, when the content is below the upper limit of the above range, This is because the mechanical properties of the cured adhesive sheet tend to be higher. In addition, when using a mixture of an organopolysiloxane having silicon-bonded hydrogen atoms only at both ends of the molecular chain and an organopolysiloxane having silicon-bonded hydrogen atoms in the side chains of the molecular chain as this component, the former organopolysiloxane The content of is preferably such that the molar ratio of the silicon-bonded hydrogen atoms in this component to the alkenyl groups in component (1-1) is within the range of 0.01 to 10, and is preferably 0.1 to 10. The amount is more preferably within the range of 10, and even more preferably the amount is within the range of 0.1 to 5. The content of the latter organopolysiloxane shall be such that the molar ratio of the silicon-bonded hydrogen atoms in this component to the alkenyl groups in component (1-1) is within the range of 0.5 to 20. The amount is preferably within the range of 0.5 to 10, more preferably the amount is within the range of 0.5 to 5.

(1-3) Curing Catalyst Although the curing catalyst is not essential, a preferred example is a platinum-based catalyst for hydrosilylation reactions. Examples of platinum-based catalysts for hydrosilylation reactions include fine platinum powder, platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, complexes of platinum and diketones, complexes of chloroplatinic acid and olefins, and chloroplatinic acid and alkenylsiloxanes. Examples include complexes with and those supported on carriers (alumina, silica, carbon black, etc.). Among these, it is preferable to use a complex of chloroplatinic acid and alkenylsiloxane because of its high catalytic activity. Further, it is more preferable to use a complex of chloroplatinic acid and divinyltetramethyldisiloxane. The blending amount of this component is preferably in the range of 1 to 1000 parts by mass as platinum metal atoms, and should be in the range of 1 to 100 parts by mass, based on 1 million parts by mass of component (1-1). is more preferable.

(1-4) Filler It is preferable to add the filler in order to improve the mechanical strength of the addition-curable curable organopolysiloxane composition, and it is usually a known filler used in the compounding of silicone rubber. Compounds of can be used. Examples of this component include fumed silica, precipitated silica, calcined silica, crushed quartz, and powders obtained by surface-treating these silica powders with organosilicon compounds (organoalkoxysilane, organohalosilane, organosilazane, etc.). can be mentioned. In particular, in order to sufficiently improve the mechanical strength of the cured product, it is preferable to use silica powder having a BET specific surface area of 50 m ² /g or more as this component.

In addition-curable curable organopolysiloxane compositions, the addition of this component is optional, but in order to improve the mechanical strength of the cured silicone rubber, the blending amount of this component is (1-1). It is preferably in the range of 1 to 1000 parts by weight, and more preferably in the range of 1 to 400 parts by weight, per 100 parts by weight. In addition, the addition-curable curable organopolysiloxane composition may contain other optional components such as fumed titanium oxide, diatomaceous earth, iron oxide, aluminum oxide, aluminosilicate, calcium carbonate, zinc oxide, and aluminum hydroxide. It may contain inorganic fillers and organic fillers such as. The addition-curable curable organopolysiloxane composition may contain fillers whose surfaces are treated with the above-mentioned organosilicon compound. The blending amount of the filler can be selected depending on the purpose and type of filler, but it is within the range of 1 to 90 volume %, and 5 to 60 volume % based on the component (1-1). It is preferable that there be.

(1-5) Others In addition, addition-curable curable organopolysiloxane compositions contain acetylene compounds (3-methyl-1-butyn-3-ol, 3,5 -dimethyl-1-hexyn-3-ol, 3-phenyl-1-butyn-3-ol, etc.), enyne compounds (3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexene- 1-yne, etc.), organosiloxane compounds having 5% by mass or more of vinyl groups in one molecule (1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3 , 5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, methylvinylsiloxane with silanol groups at both ends of the molecular chain, methylvinylsiloxane/dimethylsiloxane copolymer with silanol groups at both ends of the molecular chain, etc. ) and other curing inhibitors (triazoles such as benzotriazole, phosphines, mercaptans, hydrazines, etc.). The content of these components is not limited, but is preferably in the range of 0.001 to 5 parts by weight per 100 parts by weight of component (1-1).

The method for preparing the addition-curable curable organopolysiloxane composition is not limited, and it can be prepared by mixing other arbitrary components as necessary. -3) It is preferable to add the remaining components to the base compound prepared by heating and mixing the components. In addition, when adding other optional components, they may be added when preparing the base compound, and if the other optional components change in quality due to heating and mixing, component (1-2) or (1-2) may be added. 4) It may be added when adding the components. Furthermore, when preparing the base compound, the above-mentioned organosilicon compound may be added to treat the surface of component (1-3) in-situ.

(condensation reaction type)
The condensation reaction type curable silicone rubber composition can be mainly composed of, for example, the following components.

(1-6) Organopolysiloxane Organopolysiloxane is a main component of a condensation reaction type curable silicone rubber composition, and is preferably a diorganopolysiloxane represented by the following chemical formula (1) or chemical formula (2). It is siloxane. The chemical formula may also be referred to as an average compositional formula.

In the above chemical formulas (1) and (2), R is a monovalent hydrocarbon group. R is an alkyl group (methyl group, ethyl group, propyl group, butyl group, 2-ethylbutyl group, octyl group, etc.), a cycloalkyl group (cyclohexyl group, cyclopentyl group, etc.), an alkenyl group (vinyl group, propenyl group, butenyl group, heptenyl group, hexenyl group, allyl group, etc.), aryl group (phenyl group, tolyl group, xylyl group, naphthyl group, diphenyl group, etc.), aralkyl group (benzyl group, phenylethyl group, etc.), and the above carbonized Selected from hydrogen groups in which at least a portion of the hydrogen atoms bonded to carbon atoms are substituted with halogen or cyano groups (chloromethyl group, trifluoropropyl group, 2-cyanoethyl group, 3-cyanopropyl group, etc.) One or more hydrocarbon groups can be mentioned. The number of carbon atoms in R is preferably 1 to 12, more preferably 1 to 10. In the above chemical formulas (1) and (2), A is an oxygen atom or a polymethylene group (including a methylene group) represented by -(CH ₂ ) _m - (m is 1 to 8). Preferably, A is an oxygen atom or an ethylene group.

In the above chemical formulas (1) and (2), n is an arbitrary number that makes the kinematic viscosity of the component (1-6) at 25°C within the range of 100 to 1,000,000 cm ² /s. The kinematic viscosity is more preferably within the range of 500 to 500,000 cm ² /s.

In the above chemical formulas (1) and (2), B is a hydrolyzable group. Examples of B include alkoxy groups (methoxy, ethoxy, propoxy, butoxy, etc.), ketooxime groups (dimethylketoxime, methylethylketoxime, etc.), acyloxy groups (acetoxy, etc.), alkenyloxy groups (isopropenyloxy), group, isobutenyloxy group, etc.). Note that x in the above chemical formulas (1) and (2) is 2 or 3.

The above component (1-6) can be produced by a known method (for example, a method by equilibrium reaction using a cyclic siloxane or a linear oligomer and an acid or base catalyst).

Note that when introducing a branched structure into the diorganopolysiloxane component (1-6), a silane or a silane containing at least one of SiO _3/2 units and SiO _4/2 units is used during polymerization. A method can be used in which siloxane is added to an extent that the diorganopolysiloxane does not gel. Regarding component (1-6), in order to reduce staining, it is preferable to use the component after removing the low-molecular-weight siloxane by washing or the like.

(1-7) Crosslinking agent As the crosslinking agent, a silane having two or more, preferably three or more, hydrolyzable groups in one molecule, or a partially hydrolyzed condensate of the silane is used. Examples of hydrolyzable groups include alkoxy groups (methoxy, ethoxy, butoxy, etc.), ketooxime groups (dimethylketoxime, methylethylketoxime, etc.), acyloxy groups (acetoxy, etc.), alkenyloxy groups (iso (propenyloxy group, isobutenyloxy group, etc.), amino groups (N-butylamino group, N,N-diethylamino group, etc.), and amide groups (N-methylacetamido group, etc.). Among these, it is preferable to use an alkoxy group, a ketoxime group, an acyloxy group, and an alkenyloxy group. The blending amount of the crosslinking agent is preferably in the range of 1 to 50 parts by weight, more preferably in the range of 2 to 30 parts by weight, and more preferably in the range of 5 to 30 parts by weight, based on 100 parts by weight of component (1-6). It is even more preferable that the amount is within the range of 20 parts by mass.

(1-8) Curing Catalyst Although a curing catalyst is not essential, curing of the curable silicone rubber composition can be accelerated by using a curing catalyst. Examples of curing catalysts include alkyltin ester compounds (dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctoate, etc.), titanate esters or titanium chelate compounds (tetraisopropoxytitanium, tetran-butoxytitanium, tetrakis(2- ethylhexoxy) titanium, dipropoxybis(acetylacetona)titanium, titanium isopropoxyoctylene glycol, etc.), other suitable organometallic compounds (zinc naphthenate, zinc stearate, zinc-2-ethyl octoate, iron-2 -ethylhexoate, cobalt-2-ethylhexoate, manganese-2-ethylhexoate, cobalt naphthenate, alkoxyaluminum compounds, etc.), aminoalkyl group-substituted alkoxysilanes (3-aminopropyltriethoxysilane, N -β(aminoethyl)γ-aminopropyltrimethoxysilane, etc.), amine compounds or their salts (hexylamine, dodecylamine phosphate, etc.), quaternary ammonium salts (benzyltriethylammonium acetate, etc.), lower fatty acids of alkali metals salts (potassium acetate, sodium acetate, lithium oxalate, etc.), alkali metal lower fatty acid salts, dialkylhydroxylamines (dimethylhydroxylamine, diethylhydroxylamine, etc.), silanes or siloxanes with guanidyl groups (tetramethylguanidylpropyl trimethoxysilane, tetramethylguanidylpropylmethyldimethoxysilane, tetramethylguanidylpropyltris(trimethylsiloxy)silane, etc.). These may be used alone or as a mixture of two or more. The amount of curing catalyst blended is preferably in the range of 0 to 20 parts by weight, more preferably in the range of 0.001 to 10 parts by weight, based on 100 parts by weight of component (1-6). It is even more preferable that the amount is in the range of 0.01 to 5 parts by mass.

(1-9) Filler Although filler is not essential, it can be suitably used for purposes such as reinforcement. Examples of fillers include reinforcing agents (fumed silica, precipitated silica, silica whose surface has been made hydrophobic with an organic silicon compound, quartz powder, talc, zeolite, bentonite, etc.), fibrous fillers ( asbestos, glass fiber, organic fiber, etc.), and basic fillers (calcium carbonate, zinc carbonate, zinc oxide, magnesium oxide, celite, etc.). Among these, it is preferable to use silica, calcium carbonate, and zeolite, and it is more preferable to use fumed silica and calcium carbonate whose surfaces have been subjected to hydrophobization treatment. The amount of the filler mentioned above can be selected depending on the purpose and type of filler, but it is within the range of 1 to 90 volume %, and 5 to 60 volume % based on the component (1-6). It is preferable that the

(1-10) Adhesion-imparting component Although the adhesion-imparting component is not essential, it is preferably used. Examples of adhesive properties include organoalkoxysilanes containing amino groups (γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, etc.), organoalkoxysilanes containing epoxy groups (γ-aminopropyltrimethoxysilane, etc.), (eg, sidoxypropyltrimethoxysilane), mercapto-containing organoalkoxysilane (γ-mercaptopropyltrimethoxysilane, etc.), and a reaction mixture of an amino group-containing organoalkoxysilane and an epoxy group-containing organoalkoxysilane. The blending amount of the adhesion-imparting component is preferably within the range of 0.1 to 5 parts by weight per 100 parts by weight of component (1-6).

The plasticity of the silicone rubber compound before curing is preferably adjusted to a range of 100 to 200. If it is less than 100, it will not be able to maintain its sheet state due to deformation due to its own weight, and it will be difficult to arrange it in accordance with the positions of bolts and nuts. Moreover, when it exceeds 200, it becomes difficult for the rubber to follow curved surfaces and unevenness even if it is suctioned. Note that in this embodiment, "plasticity" is Williams plasticity at 25°C. Williams plasticity is measured using a parallel plate plasticity meter (Williams plasticity meter) according to the measurement method specified in JIS K 6249 "Testing methods for uncured and cured silicone rubber." The thickness of the uncured rubber sheet 80 is preferably 1 to 5 mm, more preferably 1.5 to 2.5 mm. Further, the uncured rubber sheet 80 may be a laminate in which two or more layers of the above-mentioned sheet-shaped silicone rubber compound and a sheet of another material such as a cured urethane sheet are laminated.

2. Corrosion Prevention Method for Bolts and Nuts FIG. 3 shows a flowchart of the main steps of the corrosion prevention method for bolts and nuts according to the first embodiment. FIG. 4 shows a diagram for explaining the anticorrosion method for bolts and nuts according to the first embodiment. FIG. 5 shows a photograph of an example of the state after the degassing step of the anticorrosion method for bolts and nuts according to the first embodiment. FIG. 6 shows a partially enlarged photograph of an example of the state after the hardening process of the anticorrosion method for bolts and nuts according to the first embodiment. In addition, FIG. 4 shows each process of the anti-corrosion construction method in the same view as FIG. 2.

The bolt/nut corrosion prevention method according to this embodiment is a method for forming the above-mentioned anticorrosion structure 1 by applying the method to the bolts 20 and nuts 30 used to fasten the objects 50 and 51. . The bolt/nut corrosion prevention method according to this embodiment includes a coating step (S110), a degassing step (S120), and a hardening step (S130). Each step will be explained below.

2.1 Covering process (S110)
The covering step is a step of covering the parts of the bolts 20 and nuts 30 used for fastening the objects 50, 51 that protrude from the objects 50, 51 with an uncured rubber sheet 80 (Fig. 4 (see a and b). In the covering step, preferably, the legs 22 of the bolts 20, the nuts 30, and the washers 40 protruding from the objects to be fastened 50, 51 are covered with the rubber sheet 80. More specifically, in the covering step, the rubber sheet 80 is placed so as to cover the tips of the legs 22 of the four bolts 20 protruding from the objects 50 and 51 to be fastened. At this time, in the covering step, it is preferable that the outer peripheral end of the rubber sheet 80 be brought into close contact with the surface of the bolt 20 on the head 21 side of the bolt 20 of the fastened object 50, 51 so as to wrap the fastened object 50, 51 (FIG. (see b). However, in the covering step, the rubber sheet 80 does not take the form of wrapping the objects 50, 51 to be fastened, and the outer peripheral end of the rubber sheet 80 is placed on the surface of the objects 50, 51 on the leg 22 side of the bolt 20. It is okay to be in close contact. Further, in the covering step, it is preferable that a suction pipe 90 of a vacuum pump used in the degassing step (S120) described later is disposed between the rubber sheet 80 and the objects to be fastened 50, 51.

2.2 Deaeration step (S120)
In the deaeration process, air is removed between the uncured rubber sheet 80 and the objects 50, 51 to be fastened, and the air is removed from the space between the rubber sheet 80 in an uncured state and the objects 50, 51 to be fastened, and the air is removed along the curved surfaces of the parts of the bolts 20 and nuts 30 that protrude from the objects 50, 51 to be fastened. This is a step of deforming the rubber sheet 80 in an uncured state. More specifically, with the rubber sheet 80 placed so as to cover the tips of the legs 22 of the four bolts 20 protruding from the objects 50 and 51 to be fastened (see b in FIG. 4), the vacuum pump The air between the rubber sheet 80 and the objects to be fastened 50 and 51 is removed from the suction tube 90 using a vacuum cleaner. As a result, the uncured rubber sheet 80 is deformed so as to adhere closely to the tips of the legs 22 of the bolts 20 protruding from the objects 50, 51 to be fastened, and to follow the curved surface of the portions protruding from the objects 50, 51 to be fastened. (See Figure 4c and Figure 5). In this embodiment, since the rubber sheet 80 covers the fastened objects 50 and 51 in the covering step (S110) (see b in FIG. 4), the rubber sheet 80 deformed by the degassing step The bolts 20 of the fasteners 50 and 51 also come into close contact with the surface on the head 21 side (see FIG. 5). In the deaeration step, after removing air between the rubber sheet 80 and the objects 50, 51 from the suction tube 90 using a vacuum pump, the suction tube 90 is connected to the rubber sheet 80 and the objects 50, 51 to be fastened. It is preferable to remove the air from the space where the suction tube 90 was placed. Note that the degassing step is not limited to the use of a vacuum pump as long as it is possible to remove air between the rubber sheet 80 and the objects to be fastened 50, 51; for example, a battery-powered suction pump, a manual Deaeration may be performed using a pump, compressor, etc.

2.3 Curing process (S130)
The curing process is a process of curing the uncured rubber sheet 80 that has been deformed in the degassing process (S120). The curing step is preferably a step of curing the rubber sheet 80 made of silicone rubber compound (see d in FIG. 4). The curing conditions are as follows: The curing is completed by leaving the product at a normal outside temperature (10 to 30°C), but if you want to accelerate the effect and shorten the effective time, the conditions can be changed depending on the reaction type of the silicone rubber. different. For example, when using an addition reaction type organopolysiloxane composition, it may be heated to 50 to 100° C. using a heater. Furthermore, if possible, heating may be performed at 180 to 250° C. for 2 to 10 hours as secondary vulcanization. Furthermore, when using a condensation reaction type curable organopolysiloxane composition, the humidity may be artificially increased using a sprayer, a humidifier, a heating humidifier, or the like. When using a UV-curable or electron beam-curable curable organopolysiloxane composition, a silicone rubber can be obtained by irradiating the inside of a mold 80 containing the above mixture with ultraviolet rays or electron beams. . As a result, the anti-corrosion member 10 made of a silicone rubber sheet is formed so as to cover the parts of the bolts 20 and nuts 30 used for fastening the objects 50, 51 that protrude from the objects 50, 51.・The construction of the anti-corrosion method for nuts is completed. In this embodiment, the uncured rubber sheet 80 is a rubber sheet made of a condensation reaction type curable organopolysiloxane composition. For example, the uncured rubber sheet 80 (see FIG. 5) that has been deformed by the degassing process is left at room temperature for one week to be cured to form the anticorrosive member 10 shown in FIG. 6.

In such a bolt/nut corrosion prevention construction method, the corrosion prevention member 10 can be attached to a plurality of sets of bolts 20 and nuts 30 that are fastened nearby by a simple method in one construction. Therefore, compared to the conventional method of attaching anti-corrosion members to each fastening portion of a plurality of bolts 20 and nuts 30 fastened to objects 50 and 51, construction time and work load can be reduced. can be achieved. In addition, in such a bolt/nut corrosion prevention method, since the anticorrosion member 10 also covers the objects 50 and 51 to be fastened, in addition to the parts of the bolts 20 and nuts 30 that protrude from the objects 50 and 51 to be fastened, Corrosion prevention measures can also be taken for the objects 50 and 51 to be fastened. In addition, the anticorrosion structure 1 formed by this bolt/nut anticorrosion construction method may have the ends of the anticorrosion member 10 adhered to the objects 50, 51 to be fastened using silicone rubber tape or the like. Thereby, the periphery of the anti-corrosive member 10 can be sealed so that foreign matter (such as water) does not enter between the anti-corrosive member 10 and the objects 50 and 51 to be fastened from the outside.

(Second embodiment)
Next, a corrosion prevention method for bolts and nuts according to a second embodiment will be explained. Portions common to those in the previous embodiment are given the same reference numerals and redundant explanation will be omitted.

1. Structure of anti-corrosion structure FIG. 7 shows a plan view of an anti-corrosion structure in which the anti-corrosion method for bolts and nuts according to the second embodiment is applied to bolts and nuts used for fastening objects to be fastened. . FIG. 8 shows a sectional view taken along line BB of the plan view of FIG.

The anti-corrosion structure 1a is a structure in which the bolt and nut anti-corrosion method according to the second embodiment is applied to the bolts 20 and nuts 30 used to fasten the objects 50 and 51. The anti-corrosion structure 1a has a similar structure to the anti-corrosion structure 1 (see FIGS. 1 and 2), but differs from the anti-corrosion structure 1 in that it further includes a frame 60.

The frame body 60 is a member made of a rubber-like elastic body that can be brought into close contact with the objects 50 and 51 to be fastened. The rubber-like elastic body is not particularly limited as long as it can adhere closely to the objects to be fastened 50, 51, but silicone rubber, urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, nitrile rubber ( It is preferable to use thermosetting elastomers such as NBR) or styrene-butadiene rubber (SBR); thermoplastic elastomers such as urethane-based, ester-based, styrene-based, olefin-based, butadiene-based, and fluorine-based, or composites thereof. . Among the above-mentioned material candidates, silicone rubber is particularly preferred, as it has excellent rubber elasticity, heat resistance, cold resistance, and compression set, does not contain antioxidants, plasticizers, or softeners, and has little fear of bleed contamination. Further, the rubber-like elastic body may contain filler such as silica. Further, the rubber-like elastic body may be a porous body (foamed body) having holes inside.

The frame body 60 is arranged so as to surround at least the fastening portion formed by the bolts 20 and nuts 30. The frame body 60 preferably surrounds a plurality of fastening parts covered by one anticorrosion member 10, and is appropriately designed so that the uncured rubber sheet shrinks in a well-balanced manner during suction and is coated with as uniform a thickness as possible, Placed. In this embodiment, the frame 60 is a rectangular annular member arranged along the outer periphery of the objects to be fastened 50 and 51 so as to surround the four fastened parts formed by the four sets of bolts 20 and nuts 30 (Fig. 7). Note that the frame body 60 is not limited to a rectangular annular member, and may be, for example, an annular shape, a polygonal annular shape, etc., as long as it can be arranged so as to surround at least the fastening portion of the bolt 20 and nut 30. good. In the anti-corrosion structure 1a, the anti-corrosion member 10 is arranged so as to be in close contact with at least the tip of the leg portion 22 of the bolt 20 protruding from the objects to be fastened 50, 51 and the frame 60.

2. Corrosion Prevention Method for Bolts and Nuts FIG. 9 shows a flowchart of the main steps of the corrosion prevention method for bolts and nuts according to the second embodiment. FIGS. 10 and 11 are diagrams for explaining a bolt/nut corrosion prevention method according to the second embodiment. In addition, FIG. 10 and FIG. 11 show each process of the anticorrosion method in the same view as FIG. 8.

The bolt/nut corrosion prevention method according to this embodiment is a construction method that forms the above-mentioned anticorrosion structure 1a by applying the method to the bolts 20 and nuts 30 used to fasten the objects 50, 51. . The anticorrosion method for bolts and nuts according to this embodiment includes steps similar to the anticorrosion method for bolts and nuts according to the first embodiment (see FIG. 3), but a placement step ( S210) is different from the bolt/nut corrosion prevention method according to the first embodiment.

The arrangement step (S210) is a step of arranging the frame body 60 so as to surround at least the fastening portion formed by the bolts 20 and nuts 30. In this embodiment, in the arrangement step (S210), the frame body 60 is arranged along the outer periphery of the objects to be fastened 50, 51 so as to surround the four fastening parts formed by the four sets of bolts 20 and nuts 30 (Fig. 10 (see e). Then, similarly to the bolt/nut corrosion prevention method according to the first embodiment (see FIGS. 3 and 4), by performing the coating step (S110), the degassing step (S120), and the hardening step (S130), A corrosion protection structure 1a is formed (see FIGS. 9, 10 and 11).

In this embodiment, in the covering step (S110), a rubber sheet 80 is placed so as to cover the tips of the legs 22 of the four bolts 20 protruding from the objects to be fastened 50, 51 and the frame 60 (Fig. 10 (see f and g). At this time, in the covering step (S110), similarly to the first embodiment, the outer peripheral end of the rubber sheet 80 is placed on the head 21 side of the bolt 20 of the object to be fastened 50, 51 so as to wrap the object to be fastened 50, 51. (See g in FIG. 10). However, in the covering step (S110), the rubber sheet 80 does not need to wrap the above-described objects to be fastened 50, 51, and the outer peripheral end of the rubber sheet 80 may be in close contact with the frame 60. Further, in this embodiment, in the degassing step (S120), the rubber sheet 80 is placed so as to cover the ends of the legs 22 of the four bolts 20 protruding from the objects to be fastened 50, 51 and the frame body 60. In this state (see g in FIG. 10), the air between the rubber sheet 80 and the objects 50, 51 to be fastened is removed from the suction tube 90 using a vacuum pump. As a result, the uncured rubber sheet 80 is brought into close contact with the ends of the legs 22 of the bolts 20 protruding from the objects 50, 51 and the frame 60, and the curved surface of the portion protruding from the objects 50, 51 is brought into close contact with the frame 60. (see h in Figure 11). Then, in the curing step (S130), the uncured rubber sheet 80 that has been deformed in the degassing step (S120) is cured (see i in FIG. 11). As a result, the anti-corrosion member 10 made of a silicone rubber sheet covers the frame 60 and the portions of the bolts 20 and nuts 30 used for fastening the objects 50, 51 that protrude from the objects 50, 51. is formed, and the construction of the bolt/nut corrosion prevention method according to the second embodiment is completed.

The anti-corrosion method for bolts and nuts according to the second embodiment also provides the same effects as the anti-corrosion method for bolts and nuts according to the first embodiment. Generally, the surfaces of objects 50 and 51 to be fastened, such as various buildings, construction machines, processing machines, etc., to which anti-corrosion methods are applied are likely to be exposed to wind and rain, and therefore are likely to be contaminated with dust, moisture, and the like. In this case, there is a possibility that the adhesive strength between the objects to be fastened 50, 51 and the anti-corrosion member 10 will decrease due to the dirt. In the bolt/nut corrosion prevention method according to the second embodiment, a frame body 60 is arranged on the objects to be fastened 50 and 51, and the corrosion prevention member 10 is in close contact with the tip of the leg portion 22 of the bolt 20 and the frame body 60. The objects to be fastened 50 and 51 are covered. Therefore, even if dirt adheres to the objects to be fastened 50, 51, the anticorrosive member 10 can be more reliably bonded to the frame 60, thereby suppressing the possibility that the anticorrosive member 10 will come off. , more effective anti-corrosion measures can be taken.

Next, a specific example of the bolt/nut corrosion prevention method according to the first embodiment will be described. In the following specific example, the bolt/nut corrosion prevention method according to the first embodiment will be described, but the same applies to the bolt/nut corrosion prevention method according to the second embodiment.

FIG. 12 shows a photograph of an example of a corrosion-resistant structure in which the bolt and nut corrosion prevention method according to the first embodiment is applied to bolts and nuts used for fastening objects to be fastened.

The anti-corrosion structure 1 shown in FIG. 12 is constructed after the anti-corrosion method for bolts and nuts according to the first embodiment is applied to the bolts 20 and nuts 30 used to fasten the objects 50 and 51. The structure was exposed to the atmosphere for months. The anticorrosive structure 1 shown in FIG. 12 shows no rust even after being exposed to the atmosphere for three months. Therefore, the bolt/nut corrosion prevention method according to the first embodiment is an effective method as a corrosion prevention measure for the bolts 20 and nuts 30 used for fastening the objects 50 and 51 to be fastened.

3. Other Embodiments As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to these and can be implemented with various modifications.

In the second embodiment, the frame 60 is composed of an annular member that surrounds the outer periphery of a plurality of fastening portions fastened by a plurality of sets of bolts 20 and nuts 30 covered by one anti-corrosion member 10. However, the present invention is not limited thereto. For example, the frame 60 may be configured such that a plurality of rubber-like elastic bodies are arranged in a ring shape at regular intervals so as to surround the outer periphery.

The present invention can be used, for example, in bolts and nuts used in various structures such as bridges, steel towers, buildings, factories, and residences, construction machines, processing machines, and the like.

20... Bolt, 22... Leg, 30... Nut, 50, 51... Object to be fastened, 60... Frame, 80... Rubber sheet in uncured state.

Claims (5)

a step of arranging a frame made of a rubber-like elastic body capable of adhering closely to the object to be fastened so as to surround at least a fastening portion formed by a metal bolt and a metal nut used for fastening the object to be fastened;
a covering step of covering a portion of the bolt and the nut protruding from the object to be fastened with an uncured rubber sheet;
a degassing step of removing air between the rubber sheet and the object to be fastened, and deforming the rubber sheet so as to follow the curved surface of the portion protruding from the object to be fastened;
a curing step of curing the rubber sheet;
including;
A method for preventing corrosion of bolts and nuts, wherein the degassing step deforms the rubber sheet so that it comes into close contact with at least the end of the leg of the bolt protruding from the object to be fastened and the frame . The degassing step is characterized in that the rubber sheet is deformed so as to adhere at least to a tip of a leg of the bolt protruding from the object to be fastened and to follow a curved surface of a portion protruding from the object to be fastened. Corrosion prevention method for bolts and nuts as described in Item 1. The method for preventing corrosion of bolts and nuts according to claim 1 or 2, wherein the rubber sheet has a plasticity in the range of 100 to 200. The method for preventing corrosion of bolts and nuts according to any one of claims 1 to 3 , wherein the rubber sheet is a silicone rubber sheet. 5. The method for preventing corrosion of bolts and nuts according to claim 4 , wherein the rubber sheet is a condensation reaction type silicone rubber sheet.

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