JPS6082330A - Manufacture of rubber product - Google Patents

Abstract

PURPOSE:To prevent possible swelling or sinking at the connections by connecting unvulcanized rubber moldings together with a tape made of a crystaline diene based copolymer with the low melting point interposed therebetween at the connection thereof. CONSTITUTION:Unvulcanized rubber moldings are connected together with a tape mainly composed of a crystaline diene based copolymer with the melting point of 40-100 deg.C interposed therebetween at the connection thereof and undergoes a vulcanization to form a rubber product. The said crystaline diene based copolymer herein used may be any kind of crystaline copolymer comprising a conjugate diene such as butadiene, isoprene or chloroprene, optimally trans-1,4- polyisoprene. Then, a tape mainly composed of a crystaline diene based copolymer is applied on the surface of the connection of the unvulcanized moldings to preent infiltration of an antiadhesion agent, a smoothing agent of a release agent into the joint while the tape can be jointly vulcanized with the unvulcanized rubber moldings by vulcanization. This elininates the need for removing the tape after the vulcanization thereby providing a product free from swelling at the connection after the vulcanization.

Description

[Detailed Description of the Invention] Akira Kien connects unvulcanized rubber moldings and then vulcanizes them to create rubber products! li! In the manufacturing method, it is used to prevent the unvulcanized rubber molding from forming, to improve slippage, or to improve peeling from the mold in areas where the adhesion is insufficient at the connection part. The present invention relates to a method for preventing the intrusion of powder, slip agent, and M type agent, and for reinforcing the connection portion until it is vulcanized.

When manufacturing endless rubber products such as window frames and tires, or when manufacturing long rubber products, unvulcanized rubber compounds are molded into an appropriate shape and then joined, and in some cases, further molding is performed. After that, vulcanization is performed.

In this case, a sheet that prevents the unvulcanized rubber moldings from adhering to each other,
These products include those that have been coated with powder such as glue or mica to improve the lubricity when moving the molded product, and those that have been coated with powder such as glue or mica to improve release from the mold during molding or vulcanization. It is practiced to apply a suspension of powder or to spray a silicone-based or fluorine thread mold release agent. In this case, these anti-adhesive agents, lubricants, or mold release agents may enter the poorly bonded areas of the unvulcanized rubber moldings, and the bonded areas may not be completely integrated during vulcanization. This results in the problem of a defective part of the product.

In order to prevent such problems, a film of polyethylene or the like is pasted or a cloth impregnated with a rubber compound is pasted on the surface of the connection portion. If a film such as polyethylene is used, it is necessary to remove it from the product after vulcanization, and if a cloth impregnated with a rubber compound is used, the product cannot be made thinner after vulcanization. It has the disadvantage that the connection part of the connector is raised.

As a result of various studies to improve these drawbacks, the present inventors have developed a method for manufacturing rubber products by vulcanizing unvulcanized rubber molded articles together. The inventors have discovered that the drawbacks mentioned in J- can be removed by interposing a tape mainly composed of a crystalline diene polymer having a melting point of 40 to 100 C at the connection part, and have completed the present invention. Ta.

According to the present invention, by pasting a tape made of a film mainly composed of a crystalline diene polymer having a melting point of 40 to 100°C to the surface of the connection part of an unvulcanized rubber molded product, It prevents anti-adhesion agents, slip agents, or mold release agents from entering the joints of unvulcanized rubber moldings, reinforces the joints, and further allows the tape to coexist with the unvulcanized rubber moldings through vulcanization. Since vulcanization is performed, there is no need to remove the tape after vulcanization, and by using a sufficiently thin tape, it is possible to obtain a product without bulges at the joint after vulcanization.

In the present invention, if the crystalline diene polymer used in the form of a tape has a high melting point, a vulcanizing agent (sulfur), a vulcanization accelerator, or a vulcanization accelerating aid is added to make an unvulcanized rubber molded product. Rubber compounding chemicals such as rubber compounds do not diffuse sufficiently into the crystalline diene polymer used in the tape form, reducing the performance of the rubber product obtained by vulcanization. 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 of the tape at room temperature will be insufficient, 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.
If a crystalline polymer with a melting point of 00°C is not co-vulcanized with the unvulcanized rubber in the unvulcanized rubber molded product, it will reduce the physical properties of the vulcanized rubber product, especially the strength of the joints of the molded product. The diene polymer must be vulcanizable and co-vulcanizable with unvulcanized rubber.

Polymers that meet these conditions include getadiene,
Any crystalline polymer consisting of a conjugated diene such as isoprene or chloroprene may be used; the most common examples are:
Trans-1,4-polyisoprene or syndiotactic-1,2-polybutanene may be 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, so the polymer needs to have a structure that exhibits high stereoregularity. , -1.9 in the case of 4-polyisoprene
It is desirable to contain 0% or more, preferably 95% or more of trans-1,4 bonds, and in the case of syndiotactic-1,2-polybutadiene, 90% or more, preferably 95% or more of 1,2 - It is desirable to have a bond.

Such crystalline polymers include natural trans-1,4-polyisoprene such as grasshopper and gutta-percha;
Or synthetic trans-1,4-polyisoprene can be mentioned. Synthetic trans-1 preferably used in the present invention,
In the case of 4-polyisoprene, isoprene monomer is polymerized using a Ziegler catalyst, and in the case of syndiotactic-1,2-polybutadiene, butadiene monomer is polymerized using an anionic catalyst. obtained by doing.

Such a crystalline diene polymer is made into a film by a conventional method using an extruder, and then made into a tape by a conventional method. At that time, within a range that does not impair the gist of the present invention, in general, natural rubber, synthetic cis-1
, 4-polyisoprene rubber (R), polybutadiene rubber (BR)1. X-tylene-diene copolymer rubber (SB
Rt or S engineering R), acrylonitrile-diene copolymer rubber (NBRJ Taha N engineering R), chloroprene rubber (OR)
, ethylene-propylene copolymer rubber (EPT or EP
DM), butyl rubber (AER), and other synthetic rubbers may be blended.

Vulcanizing agents, vulcanization accelerators, activators, metal oxides, metal carbonates, vulcanization accelerators such as fatty acids or their derivatives, fillers, rubber reinforcing agents, and rubber used in the Saitama Rubber Industry. Softeners, plasticizers, anti-aging agents, antioxidants, anti-ozonants, ultraviolet absorbers, dyes, pigments, rubber reinforcing agents, fillers,
Rubber compounding chemicals such as rubber softeners, plasticizers, or adhesive resins are blended in an amount of 40 parts by weight or less per 100 parts of crystalline diene thread M1 combined, or crystalline diene polymers are added. The intended object of the present invention can be achieved very easily when applied to a tape of

In the present invention, a molded article made of unvulcanized rubber (C), natural rubber (NIR), cis-1,4-polyisoprene rubber (IR), polybutadiene rubber (BR), nutylene-butadiene copolymer rubber (C), SBR), styrene-isoprene copolymer rubber (SIR), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrium isoprene copolymer rubber (NIR), chloroprene rubber (OR), ethylene-propylene copolymer rubber (EPR or EPDM)
) or butyl rubber (AER) or rubber, or mixtures thereof, containing vulcanizing agents, vulcanization accelerators, activators, metal oxides, metal carbonates, fatty acids or their derivatives as represented in the image. vulcanization accelerator, as well as fillers, rubber reinforcing agents, rubber softeners, plasticizers, anti-aging agents,
Antioxidants, antiozonants, ultraviolet absorbers, dyes,
Unvulcanized rubber compositions are made by blending pigments or tackifier resins, and the compositions are molded into various shapes such as sheets, plates, rods, and hoses, and even composites of these compositions are used. means.

In the present invention, the tape mainly composed of a crystalline diene polymer can be applied to the joints between unvulcanized rubber molded products by sandwiching it between the joints, or by applying it to the joints of the joints. Various methods can be used, including a method of pasting the tape, a method of pasting it on a desired location of the molding machine where the connection part comes into contact, and a method of crimping it onto the connection part during molding. The thickness of the tape varies depending on the unvulcanized rubber molding used, its vulcanization conditions, etc., but generally it is in the range of several microns to several thousand microns, especially in the range of 5 to 200 microns. In the present invention, the rubber product is produced by interposing a tape containing a crystalline diene polymer as a main component between the unvulcanized rubber moldings, and then applying a conventional vulcanization molding method. Manufactured by. In particular, after interposing the tape at the connection part, the unvulcanized rubber molded product may be dusted with powder such as talc or mica, or a suspension of the powder may be applied, or a silicone-based or fluorine-based release agent may be applied. It is effective when molding is performed after spraying a molding agent and then vulcanization molding is performed.

The rubber product obtained in this manner shows no decrease in strength occurring at the joints, and also shows no bulges or depressions at the joints. Therefore, the method of the invention particularly comprises:
We specialize in the manufacture and manufacture of endless comb products such as tires, horn frames, and window frames.

Below, according to Examples and Comparative Examples, Mizumoto Tree 1 is J=L
(As explained in detail, the present invention is not limited to these implementations.

Reference Example 1 Using an 8-inch open roll, kneading was carried out according to the procedure shown in Table 1, and the mixture was kneaded at 145°C for 30 minutes.
A vulcanized sheet with a thickness of about 5 mm was prepared by using Tht. Dwarf) sheet 95185 dumbbell 10 H4 friends, 2
Tensile strength was measured at a tensile rate of 0 Qm/min. That Il
y.

The average value was 295 Kg/cm2.

Table 1 Natural rubber (R3S11) 100 parts by weight Sulfur 2.2 Vulcanization accelerator Tsuxela NS" 0.3 Zinc white 3 5 Stearic acid 5 Aromatic prosenium oil 2) 5) IAF carbon black 45 1) Iruuchi Shinko Chemical ( Co., Ltd., Nt-buty/l/-2-
Benzothiazyl Sulfenamide 2) Sandexf 90, manufactured by Sun Oil Co., USA Comparative Example 1 Using the same formulation as in Table 1 of Reference Example 1, a sheet with a thickness of about 5 mm was prepared by plating the unvulcanized product at room temperature. did.

After forming one end of this sheet into a wedge shape, the ends of the wedge shape were overlapped and the two sheets were pressed together with fingers to press them together. A silicone mold release agent (Shin-Etsu Silicone Co., Ltd.!!tllKF96SB) was sprayed on both sides of this sheet, and then press vulcanization was performed at 145° C. for 30 minutes.

A No. 5183 dumbbell was punched out from this sheet, perpendicular to the seam and with the seam in the center of the specimen. The tensile strength of this specimen was measured in the same manner as in Reference Example 1. The average of 10 measurements is 207kg/Cm2
C0 Example 1 After connecting two unvulcanized rubber sheets in the same manner as in Comparative Example 1, the system was made so that the seams of both sides of the sheets were hidden.
1,4-polyisoprene rubber (Rapurene R-10 manufactured by Kuraray Soprene Chemica IV Co., Ltd.) / TeI leben-based tackifier resin (Yasuhara Resin Co., Ltd. Hys Resin P x 1150)
Trans-1° 4-polyisoprene tape (Clarei Soprene Chemical Co., Ltd.) with a thickness of about 50 microns, a width of about 1 am, and a melting point of 67°C, coated with a rubber adhesive with a weight ratio of 100,770 (about 5 microns) (manufactured using Laretrans Polyisoprene TP-301) was attached.

After spraying the same silicone mold release agent as in Comparative Example 1 onto both sides of this sheet, it was vulcanized in the same manner as in Comparative Example 1 and its tensile strength was measured. The average value of the 10 pieces was 295 Kg/cm2. This value is much higher than the result of Comparative Example 1, which did not use trans-1,4-polyisoprene tape, and is much higher than the result obtained for the sheet without connection in Reference Example 1. It's the same. In addition, trans-1,
4- Even when the polyisoprene tape was applied with a fingernail, no peeling was observed.

Patent applicant RiRashi Co., Ltd. Representative Patent Attorney Ken Honda

Claims (1)

[Scope of Claims] 1) A method for manufacturing a rubber product by connecting unvulcanized rubber moldings and then vulcanizing the unvulcanized rubber moldings, wherein the connecting portion of the unvulcanized rubber moldings has a melting point of 40 to 100°C. 1. A method for producing a rubber product, which comprises connecting with a tape containing a crystalline diene polymer as a main component. 2) The manufacturing method according to claim 1, wherein the crystalline diene polymer having a melting point of 40 to 100°C is trans-1,4-polyisoprene.