KR20010096800A - Spray composition and method to improved the characteristic of emissioning of static electricity in tire - Google Patents

Abstract

The present invention relates to an exterior coating composition which improves the electrostatic discharge performance of a tire made of a tread rubber composition using a large amount of silica, and a method of applying the same, and to a filler (for example, silica, calcium carbonate, and clay) except for carbon black in the tread compound. Etc.), which is applicable to a tread compound having a ratio of 30% or more, wherein the composition is added with an appropriate amount of conductive carbon black to overcome the limitation imposed on the silica loading.

The external coating agent composition of the present invention as described above can solve the electrostatic problem of the finished product accompanying the conventional silica tire production, there is an effect that can be used up to 100% of the filler to the maximum without being limited to the silica loading amount.

Description

Exterior composition and method to improve the static discharge performance of the tire and its coating method {Spray composition and method to improved the characteristic of emission of static electricity in tire}

The present invention relates to an outer coating composition and a method of applying the same to improve the static discharge performance of a tire made of a tread rubber composition using a large amount of silica.

Conventionally, carbon black is mostly used as a filler used in rubber compositions for tires. However, due to the tread off performance of the tire when using carbon black, it is insufficient to satisfy both braking and fuel economy at the same time, and in order to overcome these limitations, the trend of using a new silica material is increasing recently.

Rubber composition using silica has excellent fuel efficiency due to the inherent characteristics of silica, and it is possible to have various applications for the purpose of improving winter performance and WET performance because there is little change in dynamic viscoelasticity with temperature. However, since the silica-based rubber composition is electrically insulated as compared to the rubber composition using general carbon black, there are various problems associated with failing to properly discharge static electricity generated in a traveling vehicle. This phenomenon occurs mainly in dry winters, and becomes more serious as the amount of silica used increases. Therefore, without solving the above problems, it is inevitable that a certain limit is imposed on the loading amount of silica, and thus there is a limit in improving the performance of the tire.

The present inventors can solve the problems caused by static electricity by manufacturing an external coating agent in which a suitable amount of conductive carbon black is added to the coating agent in order to solve the above problems, and apply it to the silica tire, thereby limiting the silica loading amount I found out that I can manufacture high-performance tires without receiving.

Accordingly, an object of the present invention is to provide an outer coating composition containing conductive carbon black in order to improve the electrostatic discharge performance and to provide a coating method using the coating composition.

(A) (b) is a figure explaining the coating method of the coating agent of this invention.

Figure 2 is a state diagram before and after wear as a result of applying the coating agent of the present invention.

<Description of the symbols for the main parts of the drawings>

1: tread extruder 2: extruder outlet 3: extrudate

The present invention is an antistatic external coating composition, in particular, an antistatic coating agent applicable to a tread compound having a ratio of fillers (for example, silica, calcium carbonate, clay, etc.) excluding carbon black in the tread compound of 30% or more, wherein the composition includes silica An appropriate amount of conductive carbon black is added to overcome the limitation imposed on the loading amount. The conductive carbon black is a linear type manufactured for the purpose of conductivity and is electrodeposited to the outside of the tire, and effectively prevents the static electricity generated during the driving of the vehicle, thereby enabling the production of high performance silica applied tires. .

Carbon blacks having the above characteristics include acetylene black (Denka black, etc.), but are not particularly limited to these types, and are suitable for the practice of the present invention as long as they are conductive and can be used as a discharge medium. .

The conductive carbon black is preferably used after being mechanically pulverized sufficiently to prevent a drop in overall performance including cracks in the coating film after coating the coating agent. The size of the particles satisfying the above requirements is preferably 50 microns or less, more preferably 30 to 50 microns. If it exceeds 50 microns, the above-mentioned performance may be deteriorated, which may cause undesirable results.

In addition, the content of the conductive carbon black added to the coating agent of the present invention is preferably 5 to 80% by weight relative to the total coating agent. The reason for limiting the above range is that if the content of the conductive carbon black is less than 5% by weight, the desired antistatic effect cannot be expected. If the content exceeds 80% by weight, the antistatic effect can be increased, but the overall physical properties of the tire may be reduced. It is not desirable to cause.

The coating agent of the present invention includes a binder and a coupling agent to allow the conductive carbon black to be physically chemically bound and trapped to the sidewall and tread rubber. These compounds are physically sufficiently entangled with the conductive carbon black in the coating agent, and chemically have unsaturated bonds so that they can co-cure with the unsaturated rubber of the tire tread portion, thereby permanently removing the conductive carbon black. It makes it possible to trap. Binders satisfying the above requirements include SBR latex and latex NBR, and coupling agents include silane, titanate or zirconate, but are not limited thereto. In general, commercially available binders and coupling agents may be purchased and used. However, in order to continuously maintain the discharge performance by trapping carbon black, which is a conductive medium, the binder is preferably used in an amount of 4.0 to 20 wt%, and a coupling agent in an amount of 0.1 to 10 wt%, based on the total coating agent.

In addition, since the coating agent of the present invention is directly exposed to the outside when used, it is required to have excellent aging durability, and may include an anti-aging agent in the coating composition to satisfy the requirements. The anti-aging agent is composed of UV stabilizers, antioxidants, ozone-resistant and these are preferably used alone or mixed two or more kinds 0.5 to 5% by weight relative to the total coating agent.

The other components may be used as they are added to the known composition, so a detailed description thereof will be omitted.

The coating agent of this invention of the above structure can be manufactured by water solubility, and can also be manufactured using the organic solvent.

Hereinafter, the coating method of the coating agent of the present invention will be described. In the coating method of the present invention, the coating agent is electrodeposited before the vulcanization process, and the conductive carbon black is bound to and trapped by the sidewall and the tread rubber through an internal binder so that the conductive carbon black is not detached even when exposed to the outside of the tire. As a result, discharge performance can be maintained semi-permanently. 1 is a specific embodiment of the coating method using the coating agent of the present invention, (a) at least at least both shoulders in the wing strip which is adjacent to the sidewall of the tire before indenting the extrudate (3) during tread extrusion; (b) electrostatic discharge channel is formed by electrodepositing only the entire outer part of the green case or the tread part before vulcanization after the molding of the tire. In FIG. 1 (a), reference numeral 1 denotes a tread extruder and reference numeral 2 denotes an extruder outlet.

Figure 2 shows the state before and after abrasion of the surface of the tire tread coated using the method (a) or (b), wherein the conductive carbon black is electrodeposited on the grooves and sipes of the pattern even if the wear progresses. This demonstrates the steady discharge of static electricity to the ground and the atmosphere. In addition, the hatched part represents the site | part to which the coating agent of this invention was apply | coated.

Hereinafter, the contents of the present invention will be described in detail with reference to examples, but the scope of the present invention is not limited to these examples.

<Examples 1 to 6>

The applied silica applied tread is a raw material rubber, based on SBR 100phr, carbon black 30phr, silica 50phr, antioxidant 2.0phr, zinc oxide 3.0phr, stearic acid 2.0phr, wax 2.0phr are mixed in Banbury mixer and discharged at 160 ℃. Got it.

The conductive coating agent applied to the tread rubber was prepared according to a general method and its composition and electrostatic discharge characteristics are shown in Table 1 below.

<Table 1> Composition of conductive coating agent and electrostatic discharge characteristics

division Comparative example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 bookbinder 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Wet Dispersant 2 2 2 2 2 2 2 Adhesion promoter 0.2 0.2 0.2 0.2 0.2 0.2 0.2 General filler 80 20 30 40 50 60 - Carbon black - 59 49 39 29 19 79 Uv stabilization 0 One One One One One One Coupling agent - 0.5 0.4 0.3 0.2 0.1 1.0 Etc 13.8 13.8 13.8 13.8 13.8 13.8 13.8 RESISTIVITY (initial) 5.67 × E12 9.77 × E3 8.85 × E5 8.12 x E7 4.33 × E9 1.69 × E11 2.43 × E3 RESISTIVITY (after 2 months left) 5.51 x E12 2.91 × E4 3.54 x E6 2.59 × E8 8.99 × E10 5.33 × E11 2.57 × E3

Comparative Example

As shown in Table 1, the conductive carbon black, the anti-aging agent, and the coupling agent was not added, except that the general filler 80phr was added in the same manner as in the Example.

According to the present invention, it is possible to solve the electrostatic problem of the finished product of the conventional silica tire manufacturing, there is an effect that can be used up to 100% of the filler to the maximum without being limited to the silica loading.

Claims (6)

An antistatic coating composition, wherein the coating composition is added with the conductive carbon black in an amount of 5 to 80% by weight relative to the total coating agent. The coating composition of claim 1 wherein the carbon black has a particle size of 50 microns or less. The method according to claim 1, wherein the addition of 4.0 to 20% by weight of the latex and 0.1 to 10% by weight of the coupling agent to maintain the discharge performance by trapping the conductive carbon black to the coating composition A coating agent composition characterized by the above-mentioned. The coating agent according to claim 1 or 3, further comprising 0.5 to 5% by weight of a mixture of a UV stabilizer, an antioxidant, and an ozone agent for stability of the coating film during external exposure of the coating agent composition. Composition. A method of applying a coating agent, characterized in that the electrostatic discharge channel is constituted by electrodepositing the coating agent of claim 1 at least on both shoulder portions of the tread in a wing strip adjacent to the sidewall in a preliminary vulcanization step. 6. The coating method of the coating agent according to claim 5, wherein the coating film of the coating agent has a thickness of 500 microns or less after vulcanization.