Wiper blade rubber

Abstract

To provide a wiper blade rubber which is excellent in wiping property and durability.SOLUTION: There is provided a wiper blade rubber 10 in which the surface layer of the contact sliding part 121 that slides in contact with another member is composed of a graphite coat layer 121b, thickness of the graphite coat layer 121b is 3 μm or more and 7 μm or less, and arithmetic average height of the surface of the graphite coat layer 121b is 1.5 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wiper blade rubber. [Background technology]

[0002] Known wiper blade rubbers for automobiles have a lip portion, which is the sliding contact portion with the windshield, coated with a graphite coating layer. For example, Patent Document 1 discloses a wiper blade rubber whose lip portion is coated with a graphite coating layer using a polyurethane resin as a binder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3821634 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a wiper blade rubber that is excellent in wiping performance and durability. [Means for solving the problem]

[0005] The present invention provides a wiper blade rubber including a contact sliding part that contacts and slides on the surface of another member, wherein the surface layer of the contact sliding part is made of a graphite coating layer, the thickness of the graphite coating layer is 3 μm or more and 7 μm or less, and the arithmetic mean height of the surface of the graphite coating layer is 1.5 μm or less. [Effects of the Invention]

[0006] According to the present invention, the thickness of the graphite coating layer constituting the surface layer of the contact sliding part is 3 μm or more and 7 μm or less, and the arithmetic mean height of the surface is 1.5 μm or less, thereby achieving excellent wiping properties and durability. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a piece of wiper blade rubber according to an embodiment; [Figure 2A] FIG. 2 is a first explanatory diagram of a method for manufacturing a wiper blade rubber according to an embodiment. [Figure 2B] FIG. 4 is a second explanatory diagram of the method for manufacturing the wiper blade rubber according to the embodiment. [Figure 2C] FIG. 10 is a third explanatory diagram of the method for manufacturing the wiper blade rubber according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] The embodiments will be described in detail below.

[0009] FIG. 1 shows a wiper blade rubber 10 according to an embodiment. The wiper blade rubber 10 is a generally flat, elongated rubber component having an attachment / holding portion 11 on one side in the width direction, a lip portion 12 on the other side in the width direction, and a neck portion 13 connecting the attachment / holding portion 11 and the lip portion 12. The thin portion of the lip portion 12 on the side opposite the neck portion 13 constitutes a contact / slide portion 121. The contact / slide portion 121 has a main body portion 121a in the center in the thickness direction and graphite coating layers 121b covering both sides of the main body portion 121a. Therefore, the surface layers on both sides of the contact / slide portion 121 are constituted by the graphite coating layers 121b.

[0010] The wiper blade rubber 10 of the embodiment is attached and held by the mounting and holding portion 11 to the vertebra of the wiper drive unit provided on the underside of the windshield of an automobile, for example, and when the wiper drive unit is driven, the lip portion 12 tilts with the neck portion 13 as a fulcrum, and the contact sliding portion 121 comes into contact with and slides against the surface of the windshield, which is another component, to wipe away rain, etc.

[0011] In the wiper blade rubber 10 according to the embodiment, the portions excluding the graphite coating layer 121b, i.e., the mounting and holding portion 11, the portions of the lip portion 12 other than the graphite coating layer 121b, and the neck portion 13, are integrally formed from a cross-linked rubber composition containing a rubber component and a rubber compounding agent.

[0012] Examples of the rubber component of the crosslinked rubber composition include natural rubber (NR), chloroprene rubber (CR), ethylene propylene diene rubber (EPDM), and styrene butadiene rubber (SBR). CR includes sulfur-modified, mercaptan-modified, and xanthogen-modified types. The rubber component preferably contains one or more of these, and from the viewpoint of obtaining excellent wiping properties and durability, a blend rubber containing NR and CR is more preferred.

[0013] When the rubber component contains NR, the Mooney viscosity of the NR is preferably 50 ml / min from the viewpoint of suppressing hardening in a low-temperature atmosphere. 1+4 (100℃) or more 80ML 1+4 (100℃) or less, preferably 55ML 1+4 (100℃) or more 65ML 1+4 (100°C) or less. This Mooney viscosity is measured in accordance with JIS K6300-1:2013 (the same applies hereinafter).

[0014] When the rubber component contains CR, the CR is preferably a mercaptan-modified type from the viewpoint of obtaining excellent wiping ability and durability. From the same viewpoint as above, the Mooney viscosity of the CR is preferably 40ML 1+4 (100℃) or more 60ML 1+4 (100℃) or less, preferably 45ML 1+4 (100℃) or more 53ML 1+4 (100℃) or less.

[0015] When the rubber component is a blend rubber containing NR and CR, the NR content is preferably greater than the CR content from the viewpoint of obtaining excellent wiping ability and durability. From the same viewpoints as above, the mass ratio of the NR content to the CR content (NR / CR) is preferably greater than 50 / 50 and not greater than 70 / 30, more preferably from 55 / 45 to 65 / 35.

[0016] Examples of rubber compounding agents for the crosslinked rubber composition include carbon black, vulcanization accelerators, processing aids, vulcanization accelerators, and antioxidants.

[0017] Carbon black is, for example, SRF (Semi-Reinforcing Furnace, ASTM number N700 series, nitrogen adsorption specific surface area is 27m 2 / g), GPF (General Purpose Furnace, ASTM number N600 series, nitrogen adsorption specific surface area is 27m 2 / g). The carbon black preferably contains SRF and / or GPF, and more preferably contains SRF from the viewpoint of obtaining excellent wiping properties and durability. The nitrogen adsorption specific surface area of ​​these carbon blacks is measured in accordance with JIS K6217-2:2017.

[0018] The nitrogen adsorption specific surface area of ​​the carbon black is preferably 20 m from the viewpoint of obtaining excellent wiping properties and durability. 2 / g or more 40m 2 / g or less, more preferably 25m 2 / g or more 30m 2 / g or less. From the same viewpoints as above, the arithmetic mean particle diameter of carbon black is preferably 50 nm or more, more preferably 65 nm or more, and preferably 100 nm or less, more preferably 70 nm or less. This arithmetic mean particle diameter is determined by observing carbon black with an electron microscope. Carbon black forms an aggregate structure in which fine particles are connected together. The particle diameter here is the primary particle diameter measured by regarding the fine particle portion as a single particle (primary particle) and approximating its diameter to a perfect circle. This primary particle diameter is measured by taking an electron microscope image of carbon black and approximating it to a perfect circle. The arithmetic mean particle diameter dn is the average of the primary particle diameters and is determined by dn = (Σnidi) / (Σni).

[0019] From the viewpoint of obtaining excellent wiping ability and durability, the content of carbon black in the crosslinked rubber composition is preferably 20 parts by mass or more and 30 parts by mass or less, more preferably 22 parts by mass or more and 29 parts by mass or less, and even more preferably 24 parts by mass or more and 28 parts by mass or less, per 100 parts by mass of the rubber component. Note that the content in the crosslinked rubber composition in the present application means the amount blended into the uncrosslinked rubber composition before crosslinking of the crosslinked rubber composition.

[0020] Examples of vulcanization accelerators include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids, and derivatives thereof. The vulcanization accelerator preferably contains one or more of these, and from the viewpoint of obtaining excellent wiping ability and durability, it is more preferable to contain a metal oxide, even more preferable to contain zinc oxide and / or magnesium oxide, and even more preferable to contain both zinc oxide and magnesium oxide. When the rubber component contains CR and the vulcanization accelerator contains a metal oxide, the metal oxide also acts as a crosslinking agent for the CR.

[0021] The content of the vulcanization accelerator in the crosslinked rubber composition is preferably 5 to 10 parts by mass, more preferably 6 to 8 parts by mass, per 100 parts by mass of the rubber component, from the viewpoint of obtaining excellent wiping ability and durability. When the vulcanization accelerator contains both zinc oxide and magnesium oxide, the content of zinc oxide is preferably greater than the content of magnesium oxide, from the same viewpoint as above. The mass ratio of the content of zinc oxide to the content of magnesium oxide is preferably 1.5 to 3.5, more preferably 2 to 3, from the same viewpoint as above.

[0022] Examples of processing aids include stearic acid, polyethylene wax, and metal salts of fatty acids. The processing aid preferably contains one or more of these, and more preferably contains stearic acid from the viewpoint of obtaining excellent wiping properties and durability. From the same viewpoint as above, the content of the processing aid in the crosslinked rubber composition is preferably 0.5 parts by mass or more and 1.5 parts by mass or less per 100 parts by mass of the rubber component.

[0023] Examples of vulcanization accelerators include sulfenamide-based vulcanization accelerators, thiourea-based vulcanization accelerators, aldehyde-ammonia-based vulcanization accelerators, aldehyde-amine-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiazole-based vulcanization accelerators, thiuram-based vulcanization accelerators, dithiocarbamate-based vulcanization accelerators, etc. The vulcanization accelerator preferably contains one or more of these, and from the viewpoint of obtaining excellent wiping ability and durability, it is more preferable to contain a sulfenamide-based vulcanization accelerator and / or a thiourea-based vulcanization accelerator, and even more preferable to contain both a sulfenamide-based vulcanization accelerator and a thiourea-based vulcanization accelerator.

[0024] The content of the vulcanization accelerator in the crosslinked rubber composition is preferably 2 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the rubber component, from the viewpoint of obtaining excellent wiping properties and durability.

[0025] Examples of the antioxidant include p-phenylenediamine-based antioxidants, diphenylamine-based antioxidants, amine-ketone-based antioxidants, monophenol-based antioxidants, bisphenol-based antioxidants, polyphenol-based antioxidants, benzimidazole-based antioxidants, dithiocarbamate-based antioxidants, phosphorous-based antioxidants, organic thioacid-based antioxidants, etc. The antioxidant may contain one or more of these.

[0026] The content of the antioxidant in the crosslinked rubber composition is preferably 2 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the rubber component, from the viewpoint of obtaining excellent wiping properties and durability.

[0027] From the viewpoint of obtaining excellent wiping properties and durability, the crosslinked rubber composition is preferably crosslinked using sulfur as a crosslinking agent. In this case, from the same viewpoint as above, the amount of sulfur blended into the uncrosslinked rubber composition is preferably 1 part by mass or more and 4 parts by mass or less per 100 parts by mass of the rubber component. The crosslinked rubber composition may be crosslinked using an organic peroxide as a crosslinking agent.

[0028] At least the portion of the cross-linked rubber composition that is to be covered with graphite coating layer 121b is preferably subjected to a chlorination treatment on the surface in order to enhance adhesion to graphite coating layer 121b.

[0029] Graphite coating layer 121b is composed of a thin film layer in which graphite is bound via a binder.

[0030] Examples of graphite include natural graphite and artificial graphite. Examples of natural graphite include flake graphite, block graphite, and clay graphite. The graphite preferably contains one or more of these, and more preferably contains flake graphite from the viewpoint of obtaining excellent wiping properties and durability. The particle diameter of the graphite is, for example, 2 μm or more and 8 μm or less.

[0031] Examples of binders include thermosetting resins, thermoplastic resins, and photocurable resins. Examples of thermosetting resins include thermosetting polyurethane resins, silicone resins, epoxy resins, phenolic resins, urea resins, and melamine resins. Examples of thermoplastic resins include polyethylene resins, polypropylene resins, polyamide resins, polyester resins, and thermoplastic polyurethane resins. Examples of photocurable resins include epoxy compounds and urethane compounds to which acrylic acid is added. From the viewpoint of obtaining excellent wiping properties and durability, the binder is more preferably a thermosetting resin, and even more preferably a thermosetting polyurethane resin.

[0032] The mass ratio of the graphite content to the binder content in graphite coating layer 121b is preferably 0.5 or more and less than 1.5, more preferably 0.75 or more and 1.25 or less, from the viewpoint of obtaining excellent wiping properties and durability.

[0033] The thickness t of graphite coating layer 121b is 3 μm or more and 7 μm or less, but from the viewpoint of obtaining excellent wiping performance and durability, it is preferably 3.5 μm or more and 6.5 μm or less, and more preferably 4 μm or more and 6 μm or less. The thickness t of graphite coating layer 121b is determined from a magnified image (e.g., 1000x magnification) of a cross section of contact-sliding part 121 in the thickness direction using a digital microscope (e.g., VHX-7000 manufactured by KEYENCE Corporation). Specifically, a reference position is set at main body part 121a in the thickness direction of contact-sliding part 121, and the distance from the reference position to the interface between main body part 121a and graphite coating layer 121b is measured at multiple points (e.g., four points) and averaged. Also, the distance from the reference position to the surface of graphite coating layer 121b is measured at multiple points (e.g., ten points) and averaged. The difference between the former and latter is defined as the thickness t of graphite coating layer 121b.

[0034] The arithmetic mean height Sa of the surface of graphite coating layer 121b is 1.5 μm or less, and from the viewpoint of obtaining excellent wiping properties and durability, it is preferably 0.3 μm or more and 1.2 μm or less, and more preferably 0.3 μm or more and 1.1 μm or less. This arithmetic mean height Sa is measured based on ISO 25178 from a magnified image of the surface (for example, 1000 times magnification) using a digital microscope (for example, VHX-7000 manufactured by KEYENCE Corporation).

[0035] The ratio (t / Sa) of the thickness t of graphite coating layer 121b to the arithmetic mean surface height Sa is preferably 3.5 or more and 6 or less, more preferably 4.5 or more and 5.5 or less, from the viewpoint of obtaining excellent wiping performance and durability.

[0036] According to the wiper blade rubber 10 of the embodiment having the above configuration, the thickness t of the graphite coating layer 121b constituting the surface layer of the contact sliding part 121 is 3 μm or more and 7 μm or less, and the arithmetic mean height Sa of the surface is 1.5 μm or less, thereby achieving excellent wiping performance and durability.

[0037] Next, a method for manufacturing the wiper blade rubber 10 according to the embodiment will be described.

[0038] First, an uncrosslinked rubber composition is prepared by compounding and kneading a rubber compounding agent containing carbon black and a crosslinking agent with a rubber component, and this uncrosslinked rubber composition is molded and crosslinked to produce a tandem molded body 20 as shown in Fig. 2A. This tandem molded body 20 has a shape in which a pair of parts of the wiper blade rubber 10 excluding the graphite coating layer 121b are butted together and bonded together with their main bodies 121a facing each other. Examples of molding methods for the tandem molded body 20 include press molding, extrusion molding, injection molding, and transfer molding.

[0039] 2B, a coating agent is applied to both surfaces of the pair of joined main bodies 121a in tandem molded body 20 and solidified to form graphite coating layer 121b. When chlorination treatment is performed, it is preferable to perform the chlorination treatment on tandem molded body 20 before the coating agent is applied.

[0040] The coating agent contains solids including graphite and a binder before solidification, and an organic solvent for dissolving or dispersing the solids. The solids concentration of the coating agent is, for example, 3% by mass or more and 30% by mass or less. Examples of organic solvents include aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alcohol solvents, ketone solvents, and ester solvents. Examples of aromatic hydrocarbon solvents include benzene, toluene, and xylene. Examples of aliphatic hydrocarbon solvents include n-hexane, isohexane, cyclohexane, n-octane, isooctane, decane, and dodecane. Examples of alcohol solvents include methanol, ethanol, and isopropanol. Examples of ketone solvents include methyl ethyl ketone and methyl isobutyl ketone. Examples of ester solvents include ethyl acetate and isobutyl acetate. It is preferable that the organic solvent contains one or more of these.

[0041] The coating of the coating agent is preferably performed by spray coating using a spray nozzle from the viewpoint of controlling the thickness t and the arithmetic mean height Sa of the surface of the graphite coating layer 121b. The thickness t of the graphite coating layer 121b can be controlled by the amount of coating agent sprayed. The arithmetic mean height Sa of the surface of the graphite coating layer 121b can be controlled by the back pressure, nozzle opening, atomization pressure of the spray nozzle, and the relative movement speed between the spray nozzle and the tandem molded body 20, which is the workpiece. Specifically, the arithmetic mean height Sa of the surface of the graphite coating layer 121b can be increased by increasing at least one of the back pressure, nozzle opening, and atomization pressure of the spray nozzle and / or decreasing the relative movement speed between the spray nozzle and the tandem molded body 20, which is the workpiece. Conversely, to reduce the arithmetic mean height Sa of the surface of the graphite coating layer 121b, at least one of the back pressure, nozzle opening and atomization pressure of the spray nozzle can be reduced, and / or the relative movement speed between the spray nozzle and the workpiece, i.e., the tandem molded body 20, can be increased.

[0042] Then, as shown in FIG. 2C, a pair of wiper blade rubbers 10 can be manufactured by cutting the tandem molded body 20 having the graphite coating layer 121b formed thereon in the center.

[0043] In the above embodiment, the graphite coating layer 121b is provided on each of both surfaces of the contact sliding portion 121 of the lip portion 12, but this is not particularly limited to this and the graphite coating layer 121b may also be provided on other portions. [Example]

[0044] (Wiper blade rubber) The wiper blade rubbers of the following Examples 1 to 4 and Comparative Examples 1 to 6 were produced with the same configuration as the above embodiment. The configurations of each are also shown in Tables 1 and 2.

[0045] Example 1 NR (Mooney viscosity: 60ML1+4 (100℃)) and CR (mercaptan modified type, Mooney viscosity: 45-53ML 1+4 A blend rubber prepared by mixing NR and CR at a mass ratio of 60 / 40 (100°C) was used as the rubber component. SRF (nitrogen adsorption specific surface area: 27 m) was used for 100 parts by mass of this rubber component. 2 An uncrosslinked rubber composition was prepared by mixing and kneading 26 parts by mass of 2,000 sintered rubber (100% sintered rubber, ...

[0046] A coating agent was prepared containing 8% by mass of flake graphite, 8% by mass of a mixture of a polyether-based urethane prepolymer to form a binder, a chain extender of blocked isocyanate, and a curing agent, as well as 50% by mass of the organic solvents methyl ethyl ketone and 10% by mass of xylene.

[0047] A graphite coating layer was formed by spraying a coating agent onto the contact sliding areas on both sides of the tandem compact using a spray nozzle and then hardening the coating agent. The thickness t of the graphite coating layer and the arithmetic mean surface height Sa were controlled by combining the coating conditions of the spray nozzle back pressure, nozzle opening, atomization pressure, and relative movement speed between the spray nozzle and the tandem compact.

[0048] A pair of wiper blade rubbers was produced by cutting the center of the tandem molded article on which the graphite coating layer was formed. This wiper blade rubber was designated Example 1. The wiper blade rubber of Example 1 had a graphite coating layer thickness t of 3.5 μm and an arithmetic mean height Sa of the surface of the graphite coating layer of 0.71 μm. The graphite coating layer thickness t and the arithmetic mean height Sa of the surface were measured using a digital microscope (VHX-7000, manufactured by KEYENCE Corporation) with a magnification of 1000 times, using the method described in the above embodiment (the same applies hereinafter).

[0049] <Example 2> Example 2 was a wiper blade rubber produced in the same manner as Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 5.1 μm and the arithmetic mean height Sa of the surface was 1.02 μm.

[0050] Example 3 Example 3 was a wiper blade rubber produced in the same manner as Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 6.7 μm and the arithmetic mean height Sa of the surface was 1.2 μm.

[0051] Example 4 Example 4 was a wiper blade rubber produced in the same manner as Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 4.9 μm and the arithmetic mean height Sa of the surface was 1.32 μm.

[0052] <Comparative Example 1> Comparative Example 1 was a wiper blade rubber produced in the same manner as in Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 2.7 μm and the arithmetic mean height Sa of the surface was 0.58 μm.

[0053] <Comparative Example 2> Comparative Example 2 was a wiper blade rubber produced in the same manner as in Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 6.1 μm and the arithmetic mean height Sa of the surface was 1.53 μm.

[0054] <Comparative Example 3> Comparative Example 3 was a wiper blade rubber produced in the same manner as in Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 1.9 μm and the arithmetic mean height Sa of the surface was 0.35 μm.

[0055] <Comparative Example 4> Comparative Example 4 was a wiper blade rubber produced in the same manner as in Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 7.2 μm and the arithmetic mean height Sa of the surface was 1.68 μm.

[0056] <Comparative Example 5> Comparative Example 5 was a wiper blade rubber produced in the same manner as in Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 7.8 μm and the arithmetic mean height Sa of the surface was 1.35 μm.

[0057] <Comparative Example 6> Comparative Example 6 was a wiper blade rubber produced in the same manner as in Example 1, except that the coating conditions were set so that the thickness t of the graphite coating layer was 2.9 μm and the arithmetic mean height Sa of the surface was 1.51 μm.

[0058] [Table 1]

[0059] [Table 2]

[0060] (Test evaluation method and results) The following test evaluations were carried out on the wiper blade rubbers of Examples 1 to 4 and Comparative Examples 1 to 6. The test results are shown in Table 2.

[0061] <Initial wiping performance> For each of the wiper blade rubbers of Examples 1 to 4 and Comparative Examples 1 to 6, the initial wiping performance in each of the wipe-up (OPEN) and wipe-down (CLOSE) stages was measured based on JIS D5710:1998, and the number of water droplets remaining in the M zone was recorded as hairline, heavy line, and wide line.

[0062] <Coefficient of friction> A 100 mm long test specimen was cut from each wiper blade rubber of Examples 1 to 4 and Comparative Examples 1 to 6. The test specimen's mounting and holding portion was attached to a long, narrow fixture equipped with a load cell. The fixture with the test specimen attached was then positioned on a rotatable glass disk with a diameter of 400 mm, extending radially and with the tip of the lip of the test specimen abutting against it. A vertical load of 1.67 N was applied to the fixture to press the lip of the test specimen against the glass disk. Water was sprayed onto the glass disk to wet it, and the glass disk was rotated so that the speed at the center of the test specimen accelerated from 0.025 m / s to 2.0 m / s over 20 seconds. During this time, the friction force acting on the test specimen detected by the load cell was logged. The maximum static friction force when the test specimen began to slide on the glass disk was determined, and this was divided by the vertical load (normal force) of 1.67 N to calculate the static friction coefficient. The frictional force at a speed of 2.0 m / s was also calculated, and this was divided by the normal load (normal force) of 1.67 N to calculate the coefficient of dynamic friction. The ratio of the static friction coefficient to the dynamic friction coefficient was then calculated. If this ratio is close to 1, the vehicle can start from a stationary state and smoothly transition to a sliding state.

[0063] <Abrasion resistance durability test> The wiper blade rubbers of Examples 1 to 4 and Comparative Examples 1 to 6 were mounted on an actual vehicle so that the wiper arm pressure was 16.7 N / m. A test was conducted in which 800 ml / min of water was sprayed onto the windshield to wet it, and the wiper drive motor was driven to wipe the water off the windshield with the wiper blade rubber. The speed was set so that the number of times the wiper blade rubber slid against the windshield was 45±2 times per minute, and the test was continued until the number of times it slid 300,000 times.

[0064] After the test, the sliding contact area of ​​the wiper blade rubber was observed from the side at a magnification of 200x using a digital microscope (VHX-7000, manufactured by KEYENCE Corporation). The distance from the tip line of the sliding contact area to the tip line of the graphite coating layer was measured. This distance corresponds to the amount of wear caused by the sliding contact area of ​​the wiper blade rubber repeatedly sliding against the windshield. [Industrial Applicability]

[0065] The present invention is useful in the technical field of wiper blade rubber. [Explanation of symbols]

[0066] 10 wiper blade rubber 11 Mounting holder 12 Lip 121 Contact sliding part 121a Main body 121b Graphite coating layer 13 Neck 20 Tandem molding

Claims

1. A wiper blade rubber including a contact sliding portion that contacts and slides on the surface of another member, The wiper blade rubber has a surface layer of the contact sliding portion formed of a graphite coating layer, the thickness of the graphite coating layer being 3 μm or more and 7 μm or less, and the arithmetic mean height of the surface of the graphite coating layer being 1.5 μm or less.

2. The wiper blade rubber according to claim 1, The wiper blade rubber has a ratio of the thickness of the graphite coating layer to the arithmetic mean height of the surface of 3.5 or more and 6 or less.

3. The wiper blade rubber according to claim 1, The graphite coating layer is a thin film layer of graphite bound together by a binder.

4. The wiper blade rubber according to claim 3, The wiper blade rubber, wherein the binder is a thermosetting resin.

5. The wiper blade rubber according to claim 1, The wiper blade rubber is formed of a crosslinked rubber composition except for the graphite coating layer.

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