chain

Abstract

The chain is made of an iron-based material and has a plurality of pairs of outer plates and a plurality of pairs of inner plates. The chain has a lower coating (6) containing zinc formed on the surface of the chain, and a coating (7) containing lithium silicate and sodium silicate formed on the lower coating (6). The mass ratio of the mass of the effective component of lithium silicate to the mass of the effective component of sodium silicate is 0.07 or more and 2.5 or less.

Description

Technology Field

[0001] The present invention relates to a chain made of an iron-based material and having a plurality of pairs of outer plates and a plurality of pairs of inner plates. Background Technology

[0002] Examples of anti-corrosion water-based paint compositions that improve the corrosion resistance of metal surfaces such as automobile parts and building materials include the anti-corrosion water-based paint composition of Patent Document 1. This anti-corrosion water-based paint composition contains an inorganic reactant prepared by mixing an acrylic resin, water glass, and an alkyl silicate, and water as a solvent, and is applied to the surface of a metal substrate. In this anti-corrosion water-based paint composition, the silica solid content of the water glass in the inorganic reactant is within the range of 75% by weight or more and 90% by weight or less with respect to the total amount of the silica solid content of the water glass and the alkyl silicate in the inorganic reactant. Prior art literature

[0003] Japanese Patent Publication No. 2016-3259 The problem to be solved

[0004] However, when a conventional anti-corrosion water-based paint composition as described above was applied to the surface of the chain, the corrosion resistance of the chain was insufficient.

[0005] The objective of the present invention is to provide a chain having better corrosion resistance than conventional chains. means of solving the problem

[0006] To solve the above problem, a chain according to one embodiment of the present invention is made of an iron-based material and comprises a plurality of pairs of outer plates and a plurality of pairs of inner plates, wherein the plurality of pairs of outer plates and the plurality of pairs of inner plates are connected such that the outer plates and inner plates are arranged alternately, and has a lower coating film comprising zinc formed on the surface of the chain and a coating film comprising lithium silicate and sodium silicate formed on the lower coating film, wherein the mass ratio of the mass of the effective component of lithium silicate to the mass of the effective component of sodium silicate is 0.07 or more and 2.5 or less. Brief explanation of the drawing

[0007] FIG. 1 is a cross-sectional view illustrating a chain according to an embodiment of the present invention. Figure 2 is an enlarged cross-sectional view of the surface of the outer plate of the chain shown in Figure 1, when cut by a plane perpendicular to the surface. Specific details for implementing the invention

[0008] [Technical Concept of the Present Invention]

[0009] As described above, when conventional water-based anti-corrosion paint compositions such as those in Patent Document 1 were applied to the surface of a chain, the corrosion resistance was insufficient. Furthermore, when using conventional water-based anti-corrosion paint compositions, there was a problem with the film thickness becoming too thick. The performance of anti-corrosion paint is generally proportional to the film thickness. In the so-called heavy-duty protection field, film thicknesses of 100 μm or more are sometimes used. Even in general-purpose paints, a film thickness of about 50 μm is the standard. It is common practice to apply multiple layers to increase the film thickness. While adhesion between the applied layers is essential, the upper film does not improve the anti-corrosion performance of the lower film. When applying multiple layers, labor and material costs increase. If the film thickness increases, the interlocking method of chain parts and the flexibility of the chain deteriorate. The anti-corrosion water-based paint composition of Patent Document 1 also needs to be applied thickly, and this anti-corrosion water-based paint composition was not considered for application to chains.

[0010] It is known that when a coating film containing zinc is formed on the surface of a part made of iron-based material, the occurrence of red rust (iron oxide) on the surface of the part is reduced due to the sacrificial protective action of zinc. When the inventors formed an undercoating film containing zinc on the surface of a chain part and also formed a coating film using a paint containing sodium silicate, the corrosion resistance of the chain was dramatically improved compared to the case where only the undercoating film was formed. Here, the chain is made of iron-based material and comprises a plurality of pairs of outer plates and a plurality of pairs of inner plates. The plurality of pairs of outer plates and the plurality of pairs of inner plates are connected so that the outer plates and inner plates are arranged alternately. Specifically, the pairs of outer plates are connected by two pins. The pairs of inner plates are connected by two bushes. Furthermore, the outer plates and inner plates are connected alternately with pins loosely fitted into the bushes. Iron-based material includes steel, etc. Iron-based materials may be in the form of alloys or intermetallic mixtures.

[0011] However, when a paint containing sodium silicate was used, the inventors discovered that the water resistance of the coating film was poor and slippage occurred on the surface of the chain. After careful examination, the inventors discovered that by forming a coating film containing lithium silicate and sodium silicate in a predetermined mass ratio on a zinc-containing substrate, the coating film had good water resistance and a smooth surface, and the chain had good corrosion resistance over a long period of time, and thus completed the present invention.

[0012] That is, a chain according to one embodiment of the present invention has a lower coating containing zinc formed on the surface of the chain, and a coating containing lithium silicate and sodium silicate formed on the lower coating. The mass ratio of the mass of the effective component of lithium silicate to the mass of the effective component of sodium silicate is 0.07 or more and 2.5 or less.

[0013] According to a chain according to one embodiment of the present invention, even if the outermost layer is a coating film that does not contain zinc, the sacrificial protective action of zinc contained in the underlying film is sustained, thereby providing good corrosion resistance over a long period of time. Since the coating film contains lithium silicate in addition to sodium silicate, the coating film maintains good corrosion resistance while improving water resistance. The film formation properties of the coating film are also good, and the surface of the coating film is smooth. Since the coating film does not peel off and good corrosion resistance is sustained, the film thickness can be thin. As a result, labor costs and material costs are reduced, and the deterioration of the chain's characteristic interlocking and bending is also reduced.

[0014] [Embodiment]

[0015] Chain

[0016] Hereinafter, an embodiment of the present invention will be described in detail.

[0017] The chain according to an embodiment of the present invention is made of an iron-based material. Examples of chains include bush chains and roller chains. A bush chain comprises a plurality of pairs of inner plates, a plurality of bushes, a plurality of pairs of outer plates, and a plurality of pins. The plurality of pairs of outer plates and the plurality of pairs of inner plates are connected so that the outer plates and inner plates are arranged alternately. Specifically, the inner plates have bush press-fit holes at both ends in the longitudinal direction. The pairs of inner plates are connected by pressing the bushes into the bush press-fit holes while their inner surfaces are facing each other. The outer plates have pin press-fit holes at both ends in the longitudinal direction. The pairs of outer plates are arranged between two pairs of inner plates arranged in the longitudinal direction, and also on the outer side of the inner plates, while their inner surfaces are facing each other. At the ends of a pair of outer plates, two pins are loosely fitted onto the inner circumference of two bushes, respectively, and then press-fitted into the pin insertion holes to connect the pair of outer plates and two pairs of inner plates. In this way, a chain is formed by connecting multiple pairs of outer plates and multiple pairs of inner plates so that the outer plates and inner plates are arranged alternately. In the case of a roller chain, rollers are also loosely fitted onto the outer circumference of the bushes.

[0018] Specific shapes of the inner plate and outer plate used in the chain of the present invention include small plate-shaped plates, gourd-shaped plates, etc.

[0019] <Lower limb capsule>

[0020] A zinc-containing undercoat is formed on the surface of the chain according to an embodiment of the present invention. The undercoat may be formed, for example, using a zinc-rich paint. A zinc-rich paint is a paint containing a large amount of zinc, for example, containing 70% or more. When the zinc-rich paint contains zinc powder, it is preferable that the zinc powder be in the form of flakes. By making it in the form of flakes, the specific surface area increases and the contact between the powders becomes denser, thereby obtaining a protective barrier effect (passive corrosion resistance) based on the flake shape in addition to the active corrosion resistance of the metal itself. The undercoat may be formed, for example, by impact galvanizing. Impact galvanizing refers to a coating that forms a uniform zinc alloy film on the surface of a workpiece by projecting, for example, particles consisting of an iron core and an outer shell made of a zinc alloy onto the surface of the workpiece using a blast device.

[0021] <Section>

[0022] A chain according to an embodiment of the present invention has a coating film comprising lithium silicate and sodium silicate formed on an underlying film. The coating film may be formed using a water-based paint comprising lithium silicate and sodium silicate. As sodium silicate, for example, No. 1 and No. 2 specified in JIS K 1408-1966 may be used. As lithium silicate, for example, one with a SiO2 / Li2O molar ratio of 3.5 or 4.5 may be used. The mass ratio of the mass of the effective component of lithium silicate to the mass of the effective component of sodium silicate is 0.07 or more and 2.5 or less. In this case, the coating film has good water resistance (moisture resistance), good film formation properties, and the chain has good corrosion resistance over a long period of time. The lower limit of the above mass ratio is more desirable as it increases to 0.077, 0.14, 0.15, 0.16, 0.23, 0.29, 0.44, 0.58, 0.62, and 0.65. The upper limit of the above mass ratio is more desirable as it decreases to 2.49, 2, 1.9, and 1.86. As for the range of the above mass ratio, 0.14 or more and 2 or less is more desirable, and 0.6 or more and 2 or less is even more desirable.

[0023] The paint containing the above lithium silicate and sodium silicate (hereinafter referred to as the overcoat paint) is obtained by mixing and stirring each component according to a conventional manufacturing method. At that time, in addition to the components described above, paint additives such as a wetting dispersant, a wetting agent, an antifoaming agent, a thickening agent, a pH adjuster, a surface modifier, and a friction coefficient modifier may be incorporated.

[0024] Examples of thickeners include hydroxyethylcellulose, methylcellulose, methylhydroxypropylcellulose, ethylhydroxyethylcellulose, and methylethylcellulose ethers, and mixtures of these substances.

[0025] In addition, the above-mentioned overcoat paint may contain an appropriate amount of water depending on the painting method, the thickness of the film, and the baking conditions, but it is preferable to contain 20 mass% or more and 99 mass% or less of water in the paint.

[0026] <Seal>

[0027] The above overcoat paint can be applied to the substrate film by immersion treatments such as brushing, spraying, immersion draining (deep drain) and immersion spinning (deep spin).

[0028] It is preferable to heat-cur the paint after applying the above-mentioned overcoat paint to the substrate film. Volatile components of the paint may be evaporated in advance by drying before curing. It is preferable to heat-cur the overcoat paint at approximately 100°C to 200°C for 10 to 60 minutes. The overcoat paint may be applied to the substrate film multiple times.

[0029] In terms of achieving good corrosion resistance and cost, the coating amount of the overcoat is 0.5 g / m² 2 Up to 10 g / m² 2 It is desirable that it is 1g / m 2 Up to 10 g / m² 2 It is more desirable that it is 3g / m 2 Up to 7 g / m² 2 It is more desirable that the total thickness of the substrate film and the coating film be 1㎛ to 30㎛, and more desirable that it be 5㎛ to 25㎛. The film thickness may be thin in order to provide good corrosion resistance. Labor costs and material costs are reduced, and the interlocking of chain parts and the flexibility of the chain are improved.

[0030] The coating film composed as described above contains lithium silicate in addition to sodium silicate, so it can have a good balance of corrosion resistance and water resistance. Furthermore, when applied over a zinc-containing substrate film formed on the chain, a sacrificial protection action that reduces zinc corrosion is obtained. Although the detailed reason is not clear, it is believed that a reaction occurs between sodium silicate and zinc, thereby maintaining the corrosion resistance of the zinc-containing substrate film over a long period. The film formation properties of the coating film are also good, and since peeling is reduced, the corrosion resistance of the chain is maintained over a long period. The surface of the coating film is smooth, and the chain can move smoothly. According to the chain of the embodiment of the present invention, it has been confirmed that good corrosion resistance is maintained even when a lubricant is applied.

[0031] Furthermore, since the coating film configured as described above does not contain aluminum, there is no risk of aluminum wear particles being generated from the coating film even when the chain is repeatedly bent. Therefore, the coating film can suitably suppress the deterioration of the chain's flexibility caused by aluminum adhesion or aluminum wear particles. Additionally, if the coating film contains aluminum, aluminum is mixed with strong alkaline sodium silicate and lithium silicate in the paint. Then, there is a risk of gas generation as aluminum reacts with the alkali in the mixture. Therefore, when using such a paint, a silane coupling agent and a silane compound are generally added to the paint to suppress the generation of gas caused by the reaction between aluminum and alkali. To suppress gas by reacting the silane coupling agent and the silane compound with aluminum, various processes are required, making the manufacturing process cumbersome. In this regard, since the coating film does not contain aluminum, there is no need to add a silane coupling agent and a silane compound to the paint. Therefore, the management of the manufacturing process can be facilitated.

[0032] Examples

[0033] The embodiments and comparative examples of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

[0034] Overpaint

[0035] [Mixing Example 1]

[0036] According to the formulation (in parts by mass) of Table 1 below, lithium silicate, sodium silicate, water, a thickener, a surface modifier, and a friction coefficient modifier were stirred and mixed at room temperature for 1 hour to obtain the composition of Formulation Example 1. The active ingredients of lithium silicate and sodium silicate are 23.4% and 40.3%, respectively. Table 1 also shows the mass of the solid content (active ingredients) of lithium silicate and sodium silicate, and the mass ratio of the mass of the active ingredient of lithium silicate to the mass of the active ingredient of sodium silicate.

[0037]

[0038] [Formulation Examples 2 to 13]

[0039] According to the formulation of Table 1 above, the overpainting paints of Formulation Examples 2 to 13 were obtained in the same manner as Formulation Example 1. The overpainting paint of Formulation Example (12) does not contain lithium silicate.

[0040] Moisture Resistance Test

[0041] Using a doctor blade, apply 20 g / m² of the overcoat paint of Formulation Examples 1 to 12 onto a glass plate measuring 150 mm in length and 100 mm in width. 2 Coating was applied. The glass plate was baked at 120°C for 15 minutes and then baked for an additional 25 minutes at 180°C. The glass plate with the formed coating was placed in a test bath at a temperature of 50°C and a relative humidity of 90% or higher for 15 hours. The residue (%) as a coating is calculated from the difference in mass of the glass plate before and after the moisture resistance test. The evaluated results are shown in Table 2 below.

[0042] The evaluation criteria for moisture resistance are as follows.

[0043] ○: 75% or more

[0044] △: 15% or more

[0045] ×: 10% or less

[0046]

[0047] The Test of the Tabernacle City

[0048] An undercoat film with a thickness of 0.5 to 20 μm was formed on a steel plate by impact galvanizing, and the overcoat paints of Formulation Examples 1 to 13 were each dip-spin coated onto the undercoat film of the steel plate. After baking at 100 to 200°C for 40 minutes, the surface was judged by touch. The results of the judgment are shown in Table 2 above.

[0049] The criteria for judgment are as follows.

[0050] ○: The surface is smooth to the touch.

[0051] △: The surface feels slightly rough to the touch, but it is smooth.

[0052] ×: The surface feels rough to the touch, causing the coating to peel off.

[0053] From Table 2, it can be seen that the overcoat paints of Formulation Examples 1 to 11 containing lithium silicate have good moisture resistance. That is, when the mass ratio (mass of the effective component of lithium silicate / mass of the effective component of sodium silicate) is 0.07 to 2.5, the moisture resistance is good. From the moisture resistance evaluation in Table 2, it can be seen that the lower limit of the mass ratio becomes more desirable as it increases to 0.077, 0.14, 0.15, and 0.16. When the mass ratio exceeds 0.16, the moisture resistance exceeds 75%. The lower limit of the mass ratio becomes even more desirable as it increases to 0.23, 0.29, 0.44, 0.58, 0.62, and 0.65. When the mass ratio exceeds 0.65, the moisture resistance becomes 90%. From the perspective of tabernacle properties, the upper limit of the above mass ratio becomes more desirable as it decreases to 2.49, 2, 1.9, and 1.86.

[0054] Chain Production

[0055] [Example 1]

[0056] FIG. 1 is a cross-sectional view illustrating a chain (10) according to Embodiment 1 of the present invention. FIG. 2 is an enlarged cross-sectional view of the outer plate (3) of the chain (10) of FIG. 1 when the surface of the outer plate (3) is cut by a plane perpendicular to the surface. The chain (10) comprises a plurality of pairs of inner plates (1), a plurality of pairs of outer plates (3), a plurality of bushes (2), a plurality of pins (4), and a plurality of rollers (5). The plurality of pairs of outer plates (3) and the plurality of pairs of inner plates (1) are connected so that the outer plates (3) and inner plates (1) are arranged alternately. Specifically, the inner plates (1) have bush insertion holes (1a) at both ends in the longitudinal direction. The pairs of inner plates (1) are arranged so that their inner surfaces face each other, and are connected in a state where the bushes (2) are inserted into the bush insertion holes (1a) at each end. FIG. 1 illustrates a cross-sectional view taken at one end of the inner plate (1) in a plane perpendicular to the plane of the inner plate (1). A roller (5) is loosely fitted to the outer surface of the bush (2). The outer plate (3) has pin insertion holes (3a) at both ends in the longitudinal direction. The pair of outer plates (3) are arranged between two pairs of inner plates (1) arranged in the longitudinal direction, and also on the outer side of the inner plate (1), with their inner surfaces facing each other. At both ends of a pair of outer plates (3), two pins (4) are loosely fitted to the inner surfaces of each of the two bushes (2) and are press-fitted into the pin insertion holes (3a). By doing so, a pair of outer plates (3) and two pairs of inner plates (1) are connected. In this manner, a chain (10) is formed by connecting a plurality of pairs of outer plates (3) and a plurality of pairs of inner plates (1) so that the outer plates (3) and inner plates (1) are arranged alternately.

[0057] Each of the inner plate (1), bush (2), outer plate (3), pin (4), and roller (5) has a base film (6) on its surface and a coating film (7) formed on the base film (6) using the overlay paint. FIG. 2 shows a state in which the base film (6) and the coating film (7) are formed on the surface of the outer plate (3).

[0058] The undercoat (6) was formed by performing impact galvanizing on the surface of each part of the chain (10). The coating film (7) was formed by applying the overcoat paint of Formulation Example 1 onto the undercoat (6) by dip spin treatment and baking at a temperature of 100 to 200°C for 40 minutes. In this manner, the chain (10) according to Example 1 was manufactured. The composition of the undercoat (6) and the coating film (7) is shown in Table 3 below.

[0059]

[0060] [Examples 2 to 11]

[0061] Chains (10) of Examples 2 to 11 were produced in the same manner as Example 1, except that the overpainting paint of Examples 2 to 11 was used as the overpainting paint used to form the coating film (7).

[0062] [Comparative Example 1]

[0063] The chain of Comparative Example 1 was produced in the same manner as Example 1, except that a coating film (7) was not formed on the lower coating film (6).

[0064] Salt Spray Test (Corrosion Resistance Evaluation Test)

[0065] The chains (10) of Examples 1 to 11 and the chain of Comparative Example 1 were placed in a salt spray test (SST) device in which a salt spray mist is generated. In accordance with JIS-Z2371, they were placed under salt spray conditions (temperature inside the test chamber 35±1℃, relative humidity inside the test chamber 95 to 98%, humidifier temperature 47±1℃, salt concentration 5w / v%, etc.). The time until reddish-blue was visually detected on the fitting connection part of the pin (4) to the outer plate (3) and on the surface of the outer plate (3) was measured. The results are shown in Table 3 above.

[0066] From Table 3, it can be seen that the chain (10) of Examples 1 to 11, having a lower coating (6) and a coating (7), has significantly improved corrosion resistance compared to the chain of Comparative Example 1, which does not have a coating (7).

[0067] From the results of the above moisture resistance test, film formation test, and corrosion resistance evaluation test, it can be seen that when the above mass ratio is 0.07 or higher and 2.5 or lower, the corrosion resistance is good, and the moisture resistance and film formation are also good. When the above mass ratio is 0.14 or higher and 2 or lower, the moisture resistance and film formation are better. When the above mass ratio is 0.6 or higher and 2 or lower, the moisture resistance is better.

[0068] As described above, it has been confirmed that a chain according to an embodiment of the present invention, which comprises lithium silicate and sodium silicate on a zinc-containing undercoat so that the mass ratio is 0.07 or more and 2.5 or less, has an improved balance of water resistance and film formation properties of the coating film and corrosion resistance of the chain, and has higher corrosion resistance than conventional methods. It is presumed that the undercoat is not limited to cases where it is formed by impact galvanizing, and that the same effect is exhibited even when, for example, a zinc-rich paint is used to form a zinc-containing undercoat.

[0069] The present invention is not limited to each of the embodiments described above, and various modifications are possible within the scope set forth in the claims. Furthermore, embodiments obtained by appropriately combining the technical means disclosed in each of the other embodiments are also included within the technical scope of the present invention. Explanation of the symbols

[0070] 1: My plate 2: Bush 3: Outer plate 4: Pin 5: Roller 6: Lower limb capsule 7: Section 10: Chain

Claims

Claim 1 A chain made of an iron-based material and having a plurality of pairs of outer plates and a plurality of pairs of inner plates, wherein the plurality of pairs of outer plates and the plurality of pairs of inner plates are connected such that the outer plates and inner plates are arranged alternately, a lower coating containing zinc formed on the surface of the chain, and a coating formed on the lower coating containing lithium silicate and sodium silicate, and not containing aluminum, wherein the mass ratio of the mass of the effective component of lithium silicate to the mass of the effective component of sodium silicate is 0.07 or more and 2.5 or less. Claim 2 In claim 1, the lower film is a chain formed by impact galvanizing. Claim 3 A chain according to claim 1 or 2, wherein the mass ratio is 0.14 or more and 2 or less. Claim 4 A chain according to claim 1 or 2, wherein the total thickness of the lower film and the coating film is 1㎛ or more and 30㎛ or less. Claim 5 delete

Images