JP-7855810-B1 - Wiper blade rubber

JP7855810B1JP 7855810 B1JP7855810 B1JP 7855810B1JP-7855810-B1

Abstract

The polymer is a blended rubber containing natural rubber and chloroprene rubber, and is made of a rubber composition containing carbon black. At least the lip portion (12) is provided with a fixed lubricant coating layer (14). The coating layer contains a binder and a fixed lubricant, has a thickness of 1.5 μm to 5 μm, the proportion of the portion not covered by the fixed lubricant is 1% or less of the total area of the coating layer on the lip portion, and the maximum void size of one uncovered portion of the coating layer is less than 600 μm² . This prevents an increase in the coefficient of friction during semi-drying and suppresses the generation of abnormal noise as it dries.

Inventors

八幡直希
山田智之
松田尚

Assignees

バンドー化学株式会社

Dates

Publication Date: 20260508
Application Date: 20260219
Priority Date: 20250225

Claims (3)

The polymer is a blend of rubber containing natural rubber and chloroprene rubber, and consists of a rubber composition containing carbon black. At least the lip portion is provided with a solid lubricant coating layer. The aforementioned coating layer is Binder and, Includes a solid lubricant, The thickness is 1.5 μm or more and 5 μm or less. The proportion of the portion not covered by the solid lubricant is 1% or less of the total area of the coating layer on the lip portion. A wiper blade rubber characterized in that the maximum void size at one point in the coating layer that is not covered by the solid lubricant is less than 600 μm² .
The binder is a thermoplastic polyurethane. The wiper blade rubber according to claim 1, characterized in that the solid lubricant is artificial graphite powder.
The wiper blade rubber according to claim 1, characterized in that the average particle size of the artificial graphite powder of the solid lubricant is 10 μm or less.

Description

This invention relates to wiper blade rubber used in automobile windshields and the like. Conventionally, as shown in Patent Document 1, for example, a wiper blade rubber having a lip portion with a coating layer applied by spray coating to a rubber substrate is known, in which the coating layer, when observed on the spray-coated surface, consists of a portion that covers the rubber substrate and a portion that does not cover the rubber substrate, and the portion that does not cover the rubber substrate consists of a plurality of holes with a diameter of 10 μm to 40 μm that are evenly formed throughout the entire surface of the coating layer without any significant bias, and these holes penetrate from the surface in contact with the rubber substrate to the outer surface of the coating layer, and the ratio of the total area of the portion that covers the rubber substrate to the total area of the portion that does not cover the rubber substrate is known to be 40:60 to 60:40. This blade rubber design incorporates areas that do not cover the rubber base material, thereby suppressing bleed-out from the rubber base material and the occurrence of blistering (blistering) of the coating layer due to bloom. Patent No. 6937307 This is a perspective view showing the appearance of the wiper blade rubber.This is a magnified photograph of the surface when the proportion of the area not covered by the solid lubricant is 1% or less of the total surface area of the coating layer on the lip.This is a magnified photograph of the surface when the proportion of the area not covered by the solid lubricant is greater than 1% of the total surface area of the coating layer on the lip. The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 shows a wiper blade rubber 10 according to an embodiment. This wiper blade rubber 10 is a generally flat, elongated rubber component, with a mounting and holding portion 11 provided on one side in the vertical direction, a lip portion 12 provided on the other side in the vertical direction, and a neck portion 13 provided to connect the mounting and holding portion and the lip portion 12. At least the area of the outer circumference of the lip portion 12 that contacts the glass surface is provided with a solid lubricant coating layer 14. In this embodiment, the wiper blade rubber 10 has a mounting and holding portion 11 that is attached and held to the vertebra of a wiper drive unit provided, for example, on the lower side of the windshield of an automobile. When the wiper drive unit is driven, the portion of the lip portion 12 with the coating layer 14 tilts with the neck portion 13 as a pivot point and slides in contact with the surface of the windshield, thereby wiping away rain and the like. The wiper blade rubber 10 according to this embodiment is formed from a crosslinked rubber composition containing a rubber component and a rubber compounding agent. Examples of rubber components include natural rubber (NR), chloroprene rubber (CR), ethylene propylene diene rubber (EPDM), and styrene butadiene rubber (SBR). Examples of CR include sulfur-modified type, mercaptan-modified type, and xanthogene-modified type. The rubber component preferably contains one or more of these, and a blended rubber containing NR and CR is more preferable from the viewpoint of obtaining excellent wiping and sliding properties, as described later. When the rubber component is a blended rubber containing NR and CR, the NR content is preferably less than the CR content from the same viewpoint. From the same viewpoint, the mass ratio of the NR content to the CR content is preferably 30/70 or more and less than 50/50, more preferably 35/65 or more and 45/55 or less. Examples of rubber compounding agents include carbon black, vulcanization accelerators, processing aids, vulcanization accelerators, and antioxidants. Examples of carbon black include channel black, furnace black, thermal black, and acetylene black. Examples of furnace black include SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, and N-234. Examples of thermal black include FT and MT. It is preferable that the carbon black contains one or more of these. The carbon black content in the crosslinked rubber composition is, for example, 20 parts by mass or more and 40 parts by mass per 100 parts by mass of rubber component. In this application, the content in the crosslinked rubber composition refers to the amount of crosslinked rubber composition blended into the uncrosslinked rubber composition before crosslinking. Examples of vulcanization accelerators include metal oxides such as zinc oxide (zinc oxide) and magnesium oxide, metal carbonates, fatty acids and their derivatives. The vulcanization accelerator preferably contains one or more of these, and from the viewpoint of obtaining excellent wiping and sliding properties, it is more preferable to include a metal oxide, even more preferable to include zinc oxide an