JP2005289334A - Tire provided with colored design and method for forming colored design - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire provided with colored design and a method for forming colored design solving a problem of the prior art. <P>SOLUTION: In the tire (1) made of a black rubber basic material, at least one design (3) is provided on an outer surface. The material is diene elastomer or rubber, i.e., an elastomer in which at least a part is obtained from diene monomer. At least one light diffraction grating (31) formed by a plurality of projection part (33) or grooves (32) arranged in parallel to each other at frequency T having height H is provided on an outer surface of design. In the method, design varied with color appeared to at lest one color different from uniform basic color of the rubber material is formed on an object made of the black rubber basic material comprising diene elastomer or rubber, i.e., the elastomer in which at least a part is obtained from diene monomer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for obtaining a decorative design that appears to be a color other than black so that it stands out against a rubber material that is essentially black in color. The present invention also relates to a tire provided on one outer surface with a design that looks at least one color different from black.

In many industries, it is desirable to mark inscriptions, logos and various designs on products or articles, one function of which is to alert future users or buyers during an exhibition, for example It is in.
This problem is particularly noticeable in the case of black rubber products such as tires or caterpillar tracks.

One way to achieve this is to apply a film of a color that stands out against black on the surface of such products. This method is proposed in Patent Document 1, and according to this method, a transfer paper (transfer) having a colored design is formed before being attached to the outer surface of a tire blank before molding (molding) and vulcanization. Made. This method is an effective way to ensure a prominent color design on the black surface, but this design always exhibits the same color regardless of the direction of viewing the tire and the direction of illumination. The black rubber product having such a transfer paper has insufficient alerting power.
In the case of a tire, the color film is bonded to the tire rubber either directly or through an intermediate adhesive layer that securely bonds the film to the tire. Apart from the difficulty of implementing this technique, there is also a problem that the transfer paper peels off due to insufficient adhesion between the transfer paper and the tire.

In U.S. Pat. No. 6,057,049, a design with several colors is formed on a rubber product by a laser acting on a black vulcanized rubber compound incorporating at least one filler with a noticeable color against black. The
Similar to the previous method, the latter method can only produce designs that exhibit the same color regardless of the direction of viewing the rubber product. This method also requires the incorporation of a colored filler that is exposed by the laser into the tire material after the tire is molded and vulcanized.

US Pat. No. 5,904,794 European Patent EP 1152904

  An object of the present invention is to provide a tire having a colored design and a method for forming the colored design, which solve the above-mentioned problems of the prior art.

  One subject of the present invention is a tire made of a black rubber-based material with at least one design on the outer surface, said material being derived from a diene elastomer or rubber, i.e. at least partly from a diene monomer. The design looks like at least one color different from the black color of the rubber base material, and is arranged on the outer surface of the design (3, 30) parallel to each other and spaced by a period T The tire is provided with at least one light diffraction grating formed of a plurality of raised portions or grooves having a height H.

Preferably, the period P of the raised portion is 1.5 microns or less, and the height H of the raised portion is at most 1 micron. This is because the diffraction effect disappears when these limits are exceeded. More preferably, the height H is 0.1 to 0.3 microns and the period P is 0.5 to 0.7 microns, and more preferably the height H is between 0.17 and 0.23 microns. Is 0.6 microns. These parameters are advantageously determined in relation to the refractive index of the material from which the design is formed.
Preferably, the portion of the tire with the design is made of a material that is within the outer surface of the tire and forms a protective layer on the outer surface and a material free of ozonolysis or antioxidants. This is because the presence of such a layer reduces the optical effect obtained by the diffraction grating.

Another object of the present invention is to view at least one design on an article made of dark or black vulcanized rubber (more specifically, but not limited to a tire, caterpillar track or tire tread), i.e. to see the design A method of providing a design that makes the design and the article more prominent by changing the color and its brightness based on the selected direction or the position of the light source relative to the surface of the article.
To solve without changing the compounding of the rubber compound that constitutes the tire, this problem exists in a rubber compound in the form of aggregates of carbon black or silica having an average size of about 0.1 microns or more. This is particularly difficult considering the presence of certain important components such as reinforcing fillers. It is also known that normal tire formulations only reflect very small amounts (10% or less) of incident light.

In accordance with the present invention, a method is proposed for forming a design on the outer surface of an article made of black vulcanized rubber that changes color, for example with respect to the direction in which the article is viewed. Stages, i.e.
Providing a base design on a support, the design being in the form of a design that is desired to be replicated on the outer surface of a rubber article, the surface of the base design having a period P and a depth; Formed by at least one set of microstructures (fine filaments) defined by H, the period P and the depth H being smaller than 1 micron to form a diffraction grating,
Placing a support provided with a basic design on a molding surface of a mold for molding a rubber article;
Making a blank of unvulcanized and unmolded rubber article;
And further forming and vulcanizing the rubber article in the mold by pressing a rubber material against the surface of the mold.

This method is surprising in view of the rubber material and the special optical properties of the rubber material, and appears on the surface of the black rubber article on at least one color different from black and of the desired design. A contoured design can be provided, and the surface of the design is formed by a set of very fine lines that form a light diffraction grating that also has a two-dimensional effect or a three-dimensional effect in the form of a hologram.
The overall black surface of such a rubber compound provided with a set of microstructures has the advantage of appearing in different colors based on the direction of illumination selected or the direction of viewing the design. The light source can also change the visible color.

In fact, when a viewer of the article moves relative to the article, the light reflected by the article, and more particularly the light reflected by a set of filaments, causes a change in the wavelength that enters the eye. Thus, markings that can change color and are noticeably noticeable against the black color of the rubber material without changing the properties of the material and without attaching "foreign substances" to the surface of the article (more specifically by metallization). Can be made.
Rubbers and rubber-like materials are known methods from "diene" elastomers or rubbers, i.e. at least partly from diene monomers (monomers with or without conjugated, 2 carbon-carbon double bonds). Should be understood to mean the elastomer obtained.

The formation parameters of a set of microstructures (ie period P and height H) are advantageously established from the refractive index of the material, based on the rubber material of interest.
More specifically, the profile of the diffraction grating formed on the rubber article can be selected from the following shapes: square, rectangular, sinusoidal or triangular. Preferably, the height H is 1 micron or less and the period is 1 micron or less. In a preferred embodiment, the height H is 0.1 to 0.3 microns and the grating profile is square, rectangular or sinusoidal. Square or rectangular profiles are obtained by microelectronic engraving, and sinusoidal profiles are obtained by holographic engraving. The latter engraving method is more general and inexpensive and the sinusoidal profile is selected according to preference.

Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings, which illustrate one example of a marking on a tire as a non-limiting example.
FIG. 1 is a partial view of a black tire sidewall 1, and a design 3 consisting of a single set of microstructures is formed on the surface 2 of the tire sidewall 1 using the method of the present invention when the tire is molded. Is done.
This design appears to be a noticeable color relative to the black color of the surface 2. If the received light is not diffracted by a set of microstructures, the design may appear black depending on the direction chosen.

FIG. 2 is a cross-sectional view taken through line II-II of design 3 of FIG. Here, a plurality of raised portions 31 separated by grooves are shown. These ridges, which are rectangular in cross section, have a height H and are arranged parallel to each other with a period P. By providing this grating, the light incident on the side surfaces 32 and 33 of the raised portion 31 is diffracted in an optimum manner. That is, all the energy reflected at at least one given wavelength is concentrated, even if this energy is weakly reflected by the essentially black rubber base material.
Considering the specific nature of the rubber-based sidewall material, the sets of microstructures or diffraction gratings that form the surface of the design are essentially parallel to each other and arranged with a period essentially equal to 0.6 microns. Consisting of a series of ridges having a height H equal to 0.2 microns.

Considering that rubber reflects very little light, the results obtained in this way are particularly stunning, and very strong or extremely strong “flash” colors are observed within a very small angle. Is done.
For a given rubber material, the observed color shade can be determined. In practice, the depth parameter H has a direct effect on the perceived color, while the microwire period P and the profile shape of each grating have a direct effect on the strength found in the design.

The manufacturing method of this tire 1 with the design 3 that looks like a color other than black is the next stage:
Creating a “master” pattern on the photosensitive resin by holographic exposure of the design to form a set of microstructures;
By making nickel galvanic growth on the master pattern, making a replica called basic replica,
Placing this basic replica on a seating provided in the tire mold;
Introducing an unmolded and unvulcanized tire into the mold, and molding and vulcanizing the tire.

  According to a preferred embodiment intended to be carried out, the nickel replica obtained in the second stage of the method is bonded to a metal insert (preferably a stainless steel insert) before being placed in the mold. The This bonding is done with a silicone adhesive that favors the physical bond between the steel insert and the replica, and this type of adhesive is stronger than an adhesive that forms a chemical bond. The steel insert is then placed in the vulcanization mold.

According to another preferred embodiment, at least one replica of this design is molded in a material (eg plastic or thermoplastic) compatible with the pressure and temperature conditions of tire molding and vulcanization. Is made from a basic replica. Preferably, a thermoplastic (eg, polyetheretherketone (PEEK)) is used that has the advantage of having excellent thermal properties even at high temperatures and capable of accurately replicating the fineness of the diffraction grating. This is made using an injection mold having a surface covered by a nickel replica. This method is very economical because a large number of thermoplastic replicas can be produced by using a single nickel pattern.
In order to further enhance the visual effect, the design is divided into several parts, i.e. parts characterized by the fact that each part has its own diffraction grating and the mean direction of the microstripes of at least two parts is different. It is advantageous to decompose.

  For example, FIGS. 3 and 4 show the same portion 20 of the tire sidewall as viewed from two different incident angles. A design 30 is provided on the surface of the portion 20, and in this case, the design 30 is formed of four portions 310, 311, 312, 313. These portions 310, 311, 312, 313 are combined together to form the design, each portion having its own diffraction grating characterized by a grating profile, height H and period P. ing.

  In this case, all the parts 310, 311, 312, and 313 have a set of the same fine filaments (the same shape, height H and period P), and the average directions of the fine filaments are different. Preferably, the angular difference is at least 10 °. Thus, a design 30 is obtained, and when the design 30 is viewed from the direction along the first incident angle (for example, FIG. 3), the portions 310, 311, 312, and 313 constituting the design 30 have different colors. Present. However, when the same design 30 is viewed from a direction along another incident angle (for example, FIG. 4), each portion exhibits a color that is different from the color of the same portion viewed from the direction along the first incident angle. .

  Note that the color of the design also changes in relation to the curvature employed by the tire sidewall (for example, when passing through the contact zone with the road surface, the curvature of the sidewall increases and the observer from the outside The design color changes.

  The present invention is not limited to the examples described and illustrated above, and can be modified in various ways without departing from the scope of the present invention. More particularly, if the material is not black, for example gray, the noticeable effect on that color (gray) is considerably reduced, but the resulting color effect still exists.

1 is a drawing showing a tire sidewall surface having a design molded on the tire sidewall that can exhibit a noticeable color relative to the black color of the tire. It is sectional drawing which follows II-II of the surface of the tire of FIG. This is a design composed of a plurality of parts, each of which shows a state where the same surface of a tire side wall provided with a design formed of a set of microstructures is viewed at one of two different incident angles. It is a drawing. This is a design composed of a plurality of parts, each of which shows a state in which the same surface of a tire side wall provided with a design formed of a set of microstructures is viewed at the other of two different incident angles. It is a drawing.

Explanation of symbols

1 Tire side wall 3, 30 Design 31 Raised part 310, 311, 312, 313 Part of design

Claims (11)

  In a tire (1) made of a black rubber base material provided with at least one design (3) on the outer surface, said material is a diene elastomer or rubber, i.e. an elastomer at least partly derived from a diene monomer. The design (3) appears to be at least one color different from the black color of the rubber base material, and the outer surface of the design (3) has a plurality of ridges of height H arranged parallel to each other with a period T (33) or at least one light diffraction grating (31) formed by the groove (32) is provided.   The tire according to claim 1, wherein the height (H) of the raised portion (33) is 1 micron or less, and the period P of the raised portion is 1.5 microns or less.   The tire according to claim 1, wherein the height H is 0.17 to 0.23 microns.   One same design (30) is formed from at least two parts, and a plurality of diffraction gratings (310, 311, 312, 313) formed by a plurality of filaments are provided on the surface of each part. The tire according to any one of claims 1 to 3, wherein the diffraction gratings have mutually different directions of stripes.   The tire according to claim 4, wherein the difference between the angle of the line in one part of the design and the angle of the line in the other part of the same design is at least 10 °.   5. The visible surface of the design is provided with at least one diffraction grating, and a hologram, that is, a three-dimensional image can be seen according to the characteristics of the diffraction grating. tire.   The tire according to any one of claims 1 to 6, wherein the tire material on which the design is arranged is free of wax and an ozonolysis inhibitor or antioxidant. A color change on an article made of a diene elastomer or rubber, ie a black rubber base material consisting at least in part of an elastomer derived from a diene monomer, which appears to be at least one color different from the uniform base color of the rubber material In a method of forming a design to
Providing a base design on a support, the design comprising at least one set suitable for forming an outer surface and a diffraction grating of light received on the surface of the article on a portion of the outer surface. With a microstructure,
Placing a support having a basic design on a mold for molding a rubber article, wherein the outer surface of the design provided with the at least one set of microstructures is placed in contact with the article to be molded; And
Making unvulcanized and unmolded blanks of rubber articles;
Introducing the blank into a mold and vulcanizing the rubber material.   9. The method of claim 8, wherein the base design is replicated in a nickel replica, and the replica is bonded to a metal support.   9. The method of claim 8, wherein the base design is replicated on a support made of a thermoplastic material that can withstand the pressure and temperature of molding and vulcanization.   A set of microstructures forming at least a part of the design is composed of a plurality of ridges (or grooves) arranged in parallel with each other, having an average height H and having a period P, and the period P is 1 The method according to any one of claims 8 to 10, wherein the depth H is not more than 5 microns and the depth H is not more than 1 micron.

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