JPH0318576B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides for rubber articles such as semi-finished products or rubber products in the middle of the manufacturing process of rubber products.
The present invention relates to a method for forming a mark for identifying a lot, etc. Conventionally, when manufacturing rubber products, in the process of molding, assembling, vulcanizing, etc. of rubber compounds, or in the product, in order to identify the brand, lot, etc.
A method has been used in which a vulcanizable rubber compound containing a dye or pigment is dissolved in a solvent and applied. However, this method has problems in terms of safety and hygiene due to the use of a solvent, and also has the disadvantage of staining the mold. As a result of various studies to solve these problems, the present inventors have developed a film or tape whose main component is a crystalline diene polymer having a melting point of 40 to 100°C as a sign forming member for rubber articles. Alternatively, the inventors have discovered that the above-mentioned drawbacks can be improved by using a sheet, and have completed the present invention. That is, the present invention provides a sign-forming member mainly composed of a crystalline diene polymer having a melting point of 40 to 100° C. in producing a rubber article having a rubber article sign from an unvulcanized rubber molded product. A method of forming a sign for a rubber article comprises attaching the sign forming member in the form of a film, tape or sheet to an unvulcanized rubber molded article. In the present invention, when the melting point of the crystalline diene polymer used in the sign forming member is high, the vulcanizing agent (sulfur) and vulcanization accelerator added to make the unvulcanized rubber molded product that forms the rubber article Or, since rubber compounding chemicals such as vulcanization accelerators do not sufficiently diffuse into the crystalline diene polymer used in the sign forming member, reducing the performance of the rubber article obtained by vulcanization, crystalline diene It is necessary that the melting point of the polymer does not exceed 100°C. On the other hand, if the melting point is low, the strength will be insufficient when used as a sign forming member in the form of a film, tape or sheet, so the melting point needs to be 40°C or higher. In the present invention, the melting point refers to the temperature of the endothermic peak on the highest temperature side of the endothermic peak due to melting of the crystal obtained by differential thermal analysis. In addition, the crystalline polymer having a melting point of 40 to 100°C used as the label forming member in the present invention is
If it is not co-vulcanized with the unvulcanized rubber in the unvulcanized rubber molding that forms the rubber article, the strength at the interface with the vulcanized rubber product sign member will be reduced, so it is possible to use unvulcanized rubber that can be vulcanized. It needs to be a diene polymer that co-vulcanizes with. Polymers satisfying these conditions may be crystalline polymers made of conjugated dienes such as butadiene, isoprene, or chloroprene, and the most preferred examples are trans-1,4-polyisoprene or syndiotactic polymers. 1,2-polybutadiene is mentioned. In particular, trans-1,4-polyisoprene is most suitable. If the crystallinity of these crystalline polymers is low, the strength of the film obtained from the polymer will be insufficient.
The polymer needs to have a structure exhibiting high stereoregularity; for example, in the case of trans-1,4-polyisoprene, it should contain 90% or more, preferably 95% or more of trans-1,4 bonds. In the case of syndiotactic-1,2-polybutadiene, it is desirable to have 1,2-bonds of 90% or more, preferably 95% or more. Such crystalline polymers include natural trans-1,4-polyisoprene, such as balata and gutta-percha, or synthetic trans-1,4-polyisoprene. In the case of synthetic trans-1,4-polyisoprene preferably used in the present invention, by polymerizing isoprene monomer using a Ziegler catalyst, and in the case of syndiotactic-1,2-polybutadiene. is obtained by polymerizing butadiene monomer using an anionic catalyst. Such a crystalline diene polymer is made into a film, tape or sheet by a conventional method using an extruder. In this case, the amount of natural rubber, synthetic cis-1,4-polyisoprene rubber ( IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), styrene-isoprene copolymer rubber (SIR), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-isoprene copolymer rubber (NIR), chloroprene Rubber (CR),
Ethylene-propylene copolymer rubber (EPR or
Rubbers such as EPDM) or butyl rubber (IIR), or mixtures thereof may also be blended. Alternatively, vulcanization accelerators such as vulcanizing agents such as sulfur, vulcanization accelerators, activators, metal oxides, metal carbonates, fatty acids or derivatives thereof, and fillers and rubber reinforcing agents as necessary. Rubber compounding chemicals such as rubber softeners, plasticizers, antiaging agents, antioxidants, antiozonants, ultraviolet absorbers, pigments, dyes, or tackifying resins may be added. In particular, it is preferable to mix pigments or dyes to color the rubber article in an appropriate color, since the brand, lot, etc. of the rubber article can be easily identified. Further, if the film, tape or sheet obtained in this manner is given letters or designs, it is useful for identifying the brand or lot of rubber articles, as in the case of coloring. In addition, the imposition of characters and designs on the sign forming member requires 40 to 100 sign forming members.
Since it is a crystalline diene polymer having a melting point of .degree. C., it can be very easily carried out near that melting point. In the present invention, molded products made of unvulcanized rubber include natural rubber (NR), cis-1,4-polyisoprene rubber (IR), polybutadiene rubber (BR),
Styrene-butadiene copolymer rubber (SBR), styrene-isoprene copolymer rubber (SIR), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-isoprene copolymer rubber (NIR),
Rubbers such as chloroprene rubber (CR), ethylene-propylene copolymer rubber (EPR or EPDM), or butyl rubber (IIR), or mixtures thereof, are combined with vulcanizing agents such as sulfur, vulcanization accelerators, activators, and metals. Vulcanization accelerating aids such as oxides, metal carbonates, fatty acids or their derivatives, as well as fillers, rubber reinforcing agents, rubber softeners, plasticizers, anti-aging agents, antioxidants, anti-ozonants, etc. , ultraviolet absorbers, dyes, pigments, or tackifier resins to form unvulcanized rubber compositions, and the compositions are molded into various shapes such as sheets, plates, rods, or hoses, or means a compound of In the present invention, a rubber article having a rubber article marker is manufactured by attaching a member for forming the rubber article marker to a desired location on the unvulcanized rubber molded article, and then vulcanizing it by a conventional method. The above-mentioned method for pasting the sign-forming member includes a method of simply crimping using the adhesiveness of the unvulcanized rubber molding, and a method of crimping by blowing hot air at a temperature higher than the melting point of the crystalline diene polymer of the sign-forming member. , a method of pressing onto a comparatively low-temperature unvulcanized rubber molded article with a heated roll having a temperature higher than the melting point of the crystalline diene polymer of the sign forming member; applying a rubber adhesive to the back side of the sign forming member; Examples include a method of adhering to a sulfur rubber molded product. In this way, an unvulcanized rubber molded product or an unvulcanized rubber composite molded product labeled with a brand name, lot number, etc. is obtained, so that the brand name or lot number can be easily identified during the manufacturing process of rubber articles. Become. Therefore, process control becomes extremely easy. It can also be used for quality control, such as checking for defective products in the manufacturing process of rubber products, where the markings are not in the designated places due to poor molding. Furthermore, it is greatly useful for inventory and distribution management of rubber products obtained from the product. Note that since this label is co-vulcanized during vulcanization of the unvulcanized rubber molded article, it does not easily peel off from the rubber article and does not cause any practical problems. The method of forming a sign for rubber articles of the present invention is useful in various rubber industries that require signs, and is particularly useful in the fields of tires and belts. For example, in the case of a tire manufactured using a bladder, after stacking unvulcanized rubber moldings and then pasting a colored crystalline diene polymer tape-shaped marking member on the part that will form the tread part, It is useful as a marker and as a check mark for molding defects. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples in any way. Example Trans-1,4-polyisoprene with a melting point of 67°C (trans bond amount: 99%, Kuraray Trans Polyisoprene TP- manufactured by Kuraray Soprene Chemical Co., Ltd.)
301) 100 parts by weight of titanium oxide (manufactured by Sakai Chemical Industry Co., Ltd.)
After kneading 10 parts by weight with an 8-inch open roll, a film with a thickness of about 50 microns was extruded.
It was slitted to a width of about 5 mm. This tape
The thickness of unvulcanized rubber kneaded according to the composition shown in Table 1 is approximately 3
I pressed it onto the mm sheet with my fingers while blowing hot air with a hair dryer. This sheet was press cured at 145°C for 15 minutes. As a result, a sheet with white lines about 5 mm in width was obtained. This white line could not be peeled off with a fingernail. 【table】

Claims (1)

[Scope of Claims] 1. In producing a rubber article having a rubber article label from an unvulcanized rubber molded product, a label forming member containing a crystalline diene polymer having a melting point of 40 to 100°C as a main component is used. A method for forming a sign for a rubber article, which comprises pasting it on an unvulcanized rubber molded article. 2. The method for forming a sign for a rubber article according to claim 1, wherein the crystalline diene polymer having a melting point of 40 to 100°C is trans-1,4-polyisoprene. 3. The method for forming a sign for a rubber article according to claim 1, wherein the sign forming member is in the form of a film, tape, or sheet.