KR102173862B1 - Method for manufacturing tire having improved durability introduced surface treatment process of rubber sheet and tread bonding process using plasma - Google Patents

Abstract

The present invention relates to a method of manufacturing a tire having improved durability by introducing a process of treating the surface of a rubber sheet using plasma and bonding a laminate including the rubber sheet.
In the method of manufacturing a tire according to the present invention, the steps of: (a) bonding a laminate including a cutting sheet using plasma, and forming the bonded laminate to manufacture a green tire; And (b) vulcanizing the green tire to manufacture a tire, wherein in the step (a), a thermal plasma jet having an output of 500 to 3,000 W is irradiated to bond the laminate to produce a green tire. I can.

Description

TECHNICAL FIELD [Method for manufacturing tire having improved durability introduced surface treatment process of rubber sheet and tread bonding process using plasma}

The present invention relates to a method for manufacturing a tire having improved durability by introducing a process of treating the surface of an unvulcanized rubber sheet using plasma and a process of bonding a laminate including the unvulcanized rubber sheet.

A typical vehicle tire includes a tread 11; Carcass 12; Belt 13; Inner liner 14; Sidewall 15; Shoulder 16; Beads 17; It has a structure including the apex 18 and the like (see Figs. 1(a) and 1(b)).

Specifically, in vehicle tires, the tread 11 is a part of the tire that is in direct contact with the surface of the road and is composed of a thick rubber sheet, and protects the carcass 12 and the belt 13 located inside. For this reason, a plate-shaped rubber sheet having excellent abrasion resistance is introduced and used.

Carcass (12) refers to the entire surface layer of a tire formed by tire cord paper, which maintains the air pressure and load inside the tire as a skeleton part of the tire, plays a role of withstanding the impact, and is formed by tire cord paper. ) Is a code layer inserted between the tread 11 and the carcass 12, and a plate-shaped rubber sheet is introduced to mitigate the impact received from the outside, and the crack or trauma of the tread 12 is directly applied to the carcass 12. It serves to prevent reaching.

The inner liner (14) plays a role of maintaining air in the tire, and is formed by introducing a plate-shaped rubber sheet having excellent air tightness in place of the tube inside the tire, and the sidewall (15) By introducing a silver plate-shaped rubber sheet, it protects the carcass 11 and performs a flexible bending motion to enhance the ride comfort.

The shoulder (16) is located between the tread (11) and the sidewall (15) and serves to easily dissipate heat generated inside the tire to the outside, and is formed by introducing a thick rubber sheet. , 17) serves to maintain the tension of the tire by allowing the tire to be mounted on the rim, and has a structure including a bead wire, a core, and a flipper.

Apex (18) serves to support the lateral stiffness of the tire as a part that directly bonds to the wheel, and is formed by introducing a rubber sheet made of a highly reinforcing rubber composition for high performance tires.

Tires having the above structure are manufactured by laminating and bonding various types of rubber sheets, and conventionally, a rubber sheet-shaped structure is manufactured using methods such as extrusion, injection, and rolling, and the manufactured structure is used as a cutter, etc. A cutting sheet to form tire treads, etc. is manufactured by cutting using a cylinder. After manufacturing a laminate by laminating each of the prepared cutting sheets on a cylindrical drum, a cement-based adhesive is applied to the laminate, and both ends of the laminate are joined to form a cylindrical shape. A tire having the above structure is manufactured by manufacturing a semi-finished product, shaping the prepared semi-finished product to manufacture a green tire, and then vulcanizing the green tire to complete the tire.

In particular, in the conventional manufacturing method as described above, the tire essentially includes a process of bonding using a cement-based adhesive mainly composed of natural rubber in order to bond the joints at both ends of the tread formed on the outermost side.

In the tire manufacturing process, the tread bonding process uses the adhesion and adhesion of cement-based adhesives to firmly adhere to each other to prevent foreign substances or release agents from entering the tread gap, and maintain the tire shape to maintain the uniformity related to the balance of the tire ( It is a process that raises uniformity and improves durability, and prevents joints from being opened in the completed tire due to repeated flexing and impact during driving.

If the tread joint of the tire occurs, the vibration of the tire intensifies when driving the vehicle, which greatly reduces the steering stability, and the tire is temporarily separated from the ground, and in severe cases, the tread is separated from the tire. For this reason, various types of cement-based adhesives that can strongly bond the tread joint have been introduced and used in the related art.

However, the conventional bonding process using a cement-based adhesive is difficult to perform, and since the cement-based adhesive has a problem of discharging harmful components to the human body, research on a method for solving such a problem is required.

Korean Patent Registration No. 10-0171588 (Publication date: 1991.11.05) Korean Patent Publication No. 10-2012-0030958 (Publication date: 2012.03.29) Korean Patent Registration No. 10-0734936 (announcement date: 2007.7.03) Korean Patent Publication No. 10-2011-0063963 (Publication date: 2011.06.15)

The present invention was conceived to solve the problems of the prior art as described above, and is eco-friendly because it does not use a cement adhesive that discharges harmful substances, and it is made to bond the rubber sheet using plasma so that the joint portion is It is intended to provide technical details on a method for manufacturing a tire having excellent long-term durability because no damage occurs.

In addition, according to the present invention, a tire having improved durability can be manufactured as the density of the rubber compound can be increased by introducing a process of plasma treatment of the surface of the rubber sheet.

In addition, the present invention eliminates the need for a separate processing process for applying an adhesive, so that the manufacturing process can be simplified, so that high-quality tires can be mass-produced in a short time, and not only the tread joint, but also the vicinity of the joint can be joined at once. It is intended to provide technical details on how this excellent tire can be manufactured.

The technical problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems that are not mentioned are clearly understood by those of ordinary skill in the technical field to which the present invention belongs from the following description. Can be.

In order to achieve the above-described technical problem, the present invention comprises the steps of: (a) bonding a laminate including a cutting sheet using plasma, and molding the bonded laminate to manufacture a green tire; And (b) vulcanizing the green tire to manufacture a tire, wherein in the step (a), the laminate is bonded by irradiating a thermal plasma jet having an output of 500 to 3,000 W. It provides a method of manufacturing.

In addition, in the method for manufacturing a tire according to the present invention, the cutting sheet includes: (1) forming a rubber compound to produce an unvulcanized rubber sheet; (2) irradiating the surface of the unvulcanized rubber sheet with a thermal plasma jet to prevent surface oxidation of the unvulcanized rubber sheet; And (3) cutting the unvulcanized rubber sheet irradiated with plasma in step (2) to a predetermined length to prepare a cutting sheet; including, in step (2), heat having an output of 100 to 1,500 W This can be done by irradiating a plasma jet.

In addition, in the step (a) of the tire manufacturing method according to the present invention, a thermal plasma jet having an output of 1,000 to 3,000 W is irradiated to the laminate to produce a green tire for manufacturing a truck bus radial (TBR tire). A thermal plasma jet having an output of 1,000 to 2,500 W may be irradiated to the laminate to produce a green tire for manufacturing a light truck radial (TBR tire), or a heat having an output of 1,000 to 2,500 W. A plasma jet may be irradiated to the laminate to prepare a green tire for manufacturing a PCR tire (passenger car radial, PCR tire).

In addition, in the tire manufacturing method according to the present invention, the cutting sheet may form a tread of the tire.

In addition, the present invention provides a tire manufactured by the method described above.

According to the manufacturing method of the tire of the present invention, the cutting sheet is joined using a thermal plasma jet, so that it is eco-friendly, and the vicinity of the joint is joined at the same time in addition to the both ends of the joint, so that it is not easily separated, and damage to the joint occurs even after the curing process As a result, tires with excellent long-term durability can be manufactured.

In addition, the present invention does not require a separate processing process of applying a cement adhesive that discharges harmful substances, and it is possible to join not only the tread joint but also each layer located near the joint at a time, thereby simplifying the manufacturing process. High-quality tires can be manufactured in large quantities.

In addition, the present invention introduces a process of surface-treating an unvulcanized rubber sheet with plasma to prevent oxidation of the sheet, and the surface-treated unvulcanized rubber sheet has a high density, so that a tire with improved durability can be manufactured. .

1 is a (a) perspective view and (b) a cross-sectional view showing the structure of a general tire.
Figure 2 is a process diagram showing each step of the method for manufacturing a tire according to the present invention.

In the present specification, "adhesive" means that both ends of the cutting sheet are bonded by irradiating a thermal plasma jet, and "adhesion" means that the cutting sheets are cross-linked through vulcanization and are firmly adhered to each other and solidified.

Hereinafter, the present invention will be described in detail.

Figure 2 is a process diagram showing each step of the method for manufacturing a tire according to the present invention.

Referring to FIG. 2, a method of manufacturing a tire according to the present invention includes the steps of: (a) bonding a laminate including a cutting sheet using plasma, and forming the bonded laminate to manufacture a green tire; And (b) vulcanizing the green tire to manufacture a tire.

The step (a) is a step of manufacturing a semi-finished product by bonding a laminate including a cutting sheet using plasma, and forming a green tire by molding the prepared semi-finished product.

The cutting sheet used to manufacture green tires may be manufactured by molding and using various known rubber compounds commonly used for manufacturing tires.

The rubber compound for manufacturing the cutting sheet may include natural rubber, synthetic rubber, or a mixture thereof.

Representative examples of natural rubber include SVR5, SVR10, SVR20, SVR30, SVRCV50, SVRCV60, SVRL, SVR3L, and RSS3, and synthetic rubbers include styrene-butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene rubber ( EPR), nitrile rubber (NBR), polychloroprene (CR), silicone rubber, acrylate rubber, and the like are typical examples.

In addition, the rubber compound may contain reinforcing agents such as carbon black, additives such as silane coupling agents, crosslinking agents such as sulfur, crosslinking accelerators such as tetramethylthiuram monosulfide, oils, chemicals, and the like. The blending ratio of natural rubber, synthetic rubber, reinforcing agent, additive, cross-linking agent, cross-linking accelerator, oil, and chemicals can be selectively adjusted according to the use of the sheet.

The cutting sheet is manufactured by molding a rubber compound, and from a tire tread, carcass, belt, inner liner, sidewall, shoulder, capply (cap ply) can be used to form.

Therefore, the laminate is a tread, carcass, belt, inner liner, sidewall, shoulder, cap ply in a conventional tire. Including, etc., to form a tread, carcass, belt, inner liner, sidewall, shoulder, cap ply, etc. It may have a structure including a sheet made of a variety of materials used for.

In particular, cutting sheets used for manufacturing green tires can be used to form tire treads, and such cutting sheets are stored by winding a continuous integrated unvulcanized rubber sheet to a drum, etc., and then cutting them by preset length. Can be manufactured.

In one example, the cutting sheet for tire tread may include: (1) forming a rubber compound to prepare an unvulcanized rubber sheet; (2) preventing surface oxidation of the unvulcanized rubber sheet by irradiating plasma on the surface of the unvulcanized rubber sheet; And (3) manufacturing a cutting sheet by cutting the unvulcanized rubber sheet irradiated with plasma in step (2) to a predetermined length; it may be used.

In step (1), an unvulcanized rubber sheet may be manufactured through a method such as extrusion, rolling, injection, or the like using a rubber compound.

The unvulcanized rubber sheet manufactured by the above method is not vulcanized (cured) and has adhesiveness, and the unvulcanized rubber sheet in this state exhibits a property that the surface is easily oxidized by reacting with oxygen in the atmosphere. The unvulcanized rubber sheet whose surface is oxidized may cause a problem in that the physical properties of the tire are deteriorated due to a decrease in adhesion to the components of each layer forming the tire during curing.

In the tire manufacturing method according to the present invention, in order to prevent such deterioration of the properties of the tire, the unvulcanized rubber sheet is prepared and then the unvulcanized rubber sheet is immediately surface-treated to prevent surface oxidation of the unvulcanized rubber sheet. Thus, it is possible to manufacture a cutting sheet having excellent adhesion to the components of each layer.

To this end, in the step (2), plasma is irradiated on the surface of the unvulcanized rubber sheet to prevent oxidation occurring on the surface of the unvulcanized rubber sheet.

In this step, the thermal plasma jet is supplied using various types of conventional thermal plasma supply devices to prevent oxidation on the surface of the unvulcanized rubber sheet, and the air remaining in the internal structure of the unvulcanized rubber sheet is removed. It is possible to form a sheet layer having a higher density than an untreated unvulcanized rubber sheet.

Preferably, the thermal plasma supply device comprises: a plasma torch for supplying a heat source for vaporizing a plasma generating gas; A DC power supply provided on one side of the plasma torch to supply power; A reaction chamber provided under the plasma torch and providing a space for generating a thermal plasma jet; Thermal plasma jet equipped with a plasma gas supply unit provided on one side of the plasma torch unit to supply plasma generation gas to generate the thermal plasma jet to the plasma torch, and a nozzle provided at one side of the reaction chamber unit to discharge the thermal plasma jet generation gas to the outside What has a structure including a discharge part can be used.

In this case, the plasma torch unit may include a cathode rod and an anode nozzle, and a plasma generating gas may be supplied between the anode nozzle and the cathode rod to generate a thermal plasma jet. In other words, the generation of thermal plasma generates a direct current arc discharge between the cathode and anode nozzles, and the plasma generated gas flows from the rear as a swirling flow, so that the thermal plasma jet generated gas is heated by the arc and heated to a high temperature. A violent thermal plasma jet stream can be emitted from the nozzle.

In particular, the thermal plasma jet supplied from the thermal plasma supply device refers to an ionizing gas composed of electrons, ions, atoms and molecules generated in the torch using a direct current arc or high frequency inductively coupled discharge. It is a high-speed jet with ultra-high temperature and high activity ranging from to tens of thousands of K.

Therefore, the temperature generated by the thermal plasma jet heats the surface of the rubber sheet in a short time compared to the temperature generated by the conventional heat treatment method or combustion method to prevent oxidation occurring on the surface of the unvulcanized rubber sheet. The density of the cutting sheet can be increased, and the bonding surface of the cutting sheet can be heated and melted in a short time.

As the plasma generating gas used in the thermal plasma generating device, nitrogen gas, argon gas, or a mixed gas of argon (Ar) and nitrogen (N ₂ ) may be used, and the plasma generating gas is used with relatively little energy using an inert gas. Emission of electrons is easy and there is an advantage in that it does not react with other gases and does not generate by-products.

In particular, diatomic molecules such as nitrogen (N ₂ ) can generate heat for a short time to melt the joints of the unvulcanized rubber sheet or the cutting sheet during the recombination process by dissociation, recombination, and desorption, and heat transfer at high temperatures. It has excellent properties.

Preferably, the plasma generating gas as described above is preferably a mixed gas of argon (Ar) and nitrogen (N ₂ ) in a volume ratio of 10:1 to 2:1 (Ar: N ₂ ), and plasma generation As the gas, by supplying a mixed gas containing argon and nitrogen in a volume ratio of 3: 1 (Ar: N ₂ ), a thermal plasma jet stream of higher output can be generated. At this time, when the volume ratio of 10: 1 (Ar: N ₂ ) is not satisfied, and an excessive amount of argon is mixed, the ratio of nitrogen is relatively very low, and the effect of generating high-power thermal plasma by the addition of nitrogen Does not appear, and if the volume ratio of 2: 1 (Ar: N ₂ ) is not satisfied and an excessive amount of nitrogen is mixed, there is a problem that it is not possible to generate high-power thermal plasma as the ratio of nitrogen is excessively increased. have.

In this step, the surface treatment of the unvulcanized rubber sheet can be performed by adjusting the output of the thermal plasma jet irradiated by the plasma gun, and the thermal plasma jet with the output of the thermal plasma jet is 100 to 1,500 W for 1 to 300 seconds. By irradiation, the unvulcanized rubber sheet can be surface treated.

If the output of the thermal plasma jet is less than 100 W or the irradiation time is less than 1 second, there may be a problem that the surface treatment is insignificant and the antioxidant effect is reduced. The output of the thermal plasma jet exceeds 1,500 W or the irradiation time is 300 If it exceeds seconds, the unvulcanized rubber sheet melts and over-vulcanization occurs, which may cause a problem in which the bonding strength of each layer forming the tire is deteriorated.

More preferably, in this step, the unvulcanized rubber sheet may be surface-treated by irradiating a thermal plasma jet having an output of 700 to 900 W on the surface of the unvulcanized rubber sheet for 5 to 30 seconds.

The thermal plasma supply device of the above structure does not need to have a separate chamber, and uses a heat-assisted plasma gun that irradiates a thermal plasma jet under normal pressure with a nozzle, and is applied to the surface of the unvulcanized rubber sheet. Irradiate the thermal plasma jet to prevent oxidation of the surface.

The step (3) is a step of manufacturing a cutting sheet by cutting the surface-treated unvulcanized rubber sheet to a predetermined length, and cutting the unvulcanized rubber sheet to a predetermined length to obtain a cutting sheet having a length suitable for tire manufacturing. Each can be manufactured.

The step of manufacturing the cutting sheet in this step can be performed using various cutting devices commonly used to cut the rubber sheet, and continuously using a cutting device equipped with a separate heating means capable of heating the cutting blade. It is possible to manufacture a cutting sheet by cutting the integrated unvulcanized rubber sheet connected in the longitudinal direction to a preset length.

In this step, the cutting sheet is manufactured so that the cutting edge is arranged in a vertical direction from the unvulcanized rubber sheet to manufacture a cutting sheet with a vertical cutting surface, or the unvulcanized rubber sheet and the cutting edge are arranged so that the cutting edge is inclined to be oblique at both ends. It is also possible to manufacture a cutting sheet having an inclined surface.

If the cutting sheet manufactured in this step is a sheet that forms a tread, the unvulcanized rubber sheet is cut to form an inclined slope at an interval spaced apart from the edge of the cutting sheet by a certain length, and the joints of the oblique slope structure are respectively A formed type of cutting sheet can be manufactured.

In addition to the cutting sheet for tread, the surface treatment as described above may include carcass; Belt; Inner liner; Sidewall; Shoulder; Cap ply; It can be introduced and used in the manufacture of a structure in the form of a sheet such as an apex, or may be used in the manufacture of a structure in the form of a bead in which a rubber layer is laminated on a wire.

The cutting sheet has been described as an example of a cutting sheet for tire tread that extrudes a rubber compound and cuts the extrudate, but is extruded to form a carcass, belt, inner liner, sidewall, shoulder, cap ply, etc. , It can be easily introduced and used for surface treatment of a plate-shaped rubber sheet manufactured by methods such as injection, rolling, etc., a laminated rubber sheet with a reinforcing layer introduced therein, and prevents oxidation of the rubber sheet. It can be configured to produce a dense rubber sheet by removing the existing air layer.

In addition, it can be used for surface treatment of structures including an inner wire and an outer rubber layer such as a bead structure.

On the other hand, the laminate may be manufactured by a method of stacking a plate-shaped cutting sheet and various rubber sheets by wrapping them around the outer circumferential surface of a cylindrical member such as a drum and connecting both ends of each sheet. In particular, the cutting sheet may be used for forming a tread of a tire.

When the cutting sheet is a part that forms a tread in the tire, a butt joint is a butt joint that combines and laminates the cutting sheet by facing both ends, or an over lay joint that allows the both ends of the cutting sheet to overlap so that the joint interface is installed wider. ) Can be laminated. Also in the overlay joint method, an overlay joint method in which both sides of the bonding surface form an oblique inclined surface or a stepped structure may be used.

In addition, the laminate is a truck bus radial (TBR tire) mounted on buses, trucks, etc., a light truck radial (TBR tire) mounted on sports utility vehicles (SUV) and light trucks, etc. It may be formed by laminating various rubber sheets including cutting sheets or the like so as to have a suitable structure for manufacturing a PCR tire (passenger car radial, PCR tire).

For example, the cutting sheet in the laminate may be laminated to have a structure including an upper tread, an under tread, and a wing strip in order to form a tread of a tire, and the upper tread (cap tread) is the part that contacts the road surface of the road, the lower tread is the part located at the lower end of the upper tread, and the wing strip is formed on both sides of the upper and lower treads to improve the adhesion of each layer forming the tire. It plays a role to let.

In this step, a cylindrical structure can be manufactured by irradiating plasma to a laminate formed by wrapping it around the outer circumference of a cylindrical member such as a drum and stacking the sheets in a continuous state, and bonding both ends of each layer forming the laminate. have.

Conventionally, the process of laminating each cut sheet on a cylindrical drum to make a laminate, and then bonding the tires using various types of cement-based adhesives to join the joints of both ends of the tread formed on the outermost side, is essentially included. .

However, the existing cement-based adhesive has a problem of discharging harmful components to the human body, and the bonding process using a cement-based adhesive is difficult to perform, and the tread joint is difficult to accurately match both cross-sections to each other, so that both cross-sections overlap. There is a problem in that the sectional thickness of the tread is not uniform due to the occurrence of the part protruding outward, and thus the problem of lowering the gripping force and steering stability of the tire due to the occurrence of tire pull occurs frequently.

In addition, in the recent tire industry, solution polymerization in which the content of styrene is increased in the rubber compound used in the tread and the content of vinyl is adjusted to improve the wet grip and rolling resistance, which is an indicator of fuel economy performance. SBR (solution SBR, S-SBR) is used. However, solution polymerization SBR has poor compatibility with natural rubber cement, and when fatigue accumulates on the adhesive interface, the tread joint is easily separated.

In order to prevent such interfacial lift, the tread rubber's adhesion is increased, and the tread joint is physically pressed and bonded during the molding process.In the case of passenger car tires, SBR rubber, which is the main component of the tread, is less adhesive than natural rubber due to the characteristics of synthetic rubber. In the process of compounding the tread rubber, a large amount of tackifier is added or a device that strongly compresses the tread joint in the molding process is used. However, even if the tread joint is physically strongly compressed, the adhesive strength is not satisfactory, and the tread portion joined before the vulcanization process is often opened.

In the present invention, unlike the conventional method of bonding the joints at both ends of the tread by applying a cement-based adhesive, the joints at both ends of the tread may be joined by irradiating the laminate with a thermal plasma jet. At this time, the thermal plasma jet is irradiated to a portion around the joints at both ends of the tread, so that not only the joint surface of the tire tread, but also the carcass layer located under the tread can be joined, thereby manufacturing a tire having excellent adhesion.

In this step, the plasma may be supplied using various types of conventional thermal plasma jet supply devices to bond the laminate, and may be performed using the same device as the thermal plasma supply device used for unvulcanized surface treatment.

In addition, in this step, a tire having excellent bonding quality can be manufactured by irradiating the laminate with thermal plasma jets having different outputs according to the structure, size and shape of the manufactured tire.

As an example, when the laminate is for manufacturing a TBR tire, the laminate may be bonded by irradiating a thermal plasma jet with an output of 1,000 to 3,000 W for 1 to 300 seconds, and use for manufacturing an LTR tire In the case of, the laminate can be bonded by irradiating the thermal plasma jet with an output of 1,000 to 2,500 W for 1 to 30 minutes, and for the purpose of manufacturing a PCR tire, a thermal plasma jet with an output of 800 to 2,500 W is 1 The laminate can be bonded by irradiating for 300 seconds.

If the output of the thermal plasma jet is less than the above range, there may be a problem in that the melting of the cutting sheet is insufficient, so that the bonding of the joint does not proceed sufficiently, and a problem that the time to irradiate the thermal plasma jet for bonding may be lengthened. . When the output of the thermal plasma jet exceeds the above range, the joint portion is melted in a short time and the cutting sheet is over-vulcanized, thereby deteriorating the physical properties of the tire.

More preferably, in order to bond the laminate, the TBR tire may be configured to bond the tread by irradiating the thermal plasma jet with an output of 1,500 to 2,000 W for 3 to 20 seconds, and the LTR tire and The PCR tire may be configured to melt the cutting sheet by irradiating a thermal plasma jet with an output of 1,000 to 1,500 W of each thermal plasma jet for 3 to 30 seconds, and then pressurize to bond the laminate.

As described above, in this step, a semi-finished product is manufactured by bonding the laminates using a thermal plasma jet, and then the prepared semi-finished product is molded to produce a green tire, which is a green tire. This can be done through the manufacturing method of a green tire.

The step (b) is a step of manufacturing a tire by vulcanizing a green tire, and in this step, a tire may be manufactured through various conventional methods of curing the green tire.

For example, in this step, the green tire is put into a vulcanizing mold with a closed space inside, and a heating medium for vulcanization is supplied to the vulcanizing mold through a nozzle, and heat and pressure are applied to vulcanize it for a certain period of time. A tire in the form of a finished product can be manufactured through a vulcanization process in which the vulcanization mold is in close contact.

According to the manufacturing method of the tire of the present invention as described above, the cutting sheet is joined using thermal plasma, so that it is eco-friendly, and the vicinity of the joint is simultaneously joined in addition to both ends of the joint so that it is not easily separated, and the joint is damaged even after the vulcanization process. Since this does not occur, a tire having excellent long-term durability can be manufactured.

In addition, the present invention does not require a separate processing process of applying a cement adhesive that discharges harmful substances, and it is possible to join not only the tread joint but also each layer located near the joint at a time, thereby simplifying the manufacturing process. High-quality tires can be manufactured in large quantities.

In addition, the present invention introduces a process of surface-treating an unvulcanized rubber sheet with a thermal plasma jet to prevent oxidation of the sheet, and the surface-treated unvulcanized rubber sheet has a high density, which makes it possible to manufacture tires with improved durability. I can.

Hereinafter, the present invention will be described in more detail by way of examples.

The examples presented are only specific examples of the present invention, and are not intended to limit the scope of the present invention.

<Example>

(1) Preparation of a tread joint specimen using a cutting sheet

Three types of rubber compounds mainly used in the manufacture of tires were selected, and the rubber compound was molded to prepare an unvulcanized rubber sheet. The first rubber compound was to prepare a non-vulcanized rubber sheet for TBR tires using a mixture containing natural rubber and carbon black, and the second rubber compound contained emulsion polymerization SBR, carbon black, and silica (1:1 weight ratio). The mixture was used to prepare a non-vulcanized rubber sheet for LTR tires, and the third rubber compound was a mixture containing solution-polymerized SBR, carbon black and silica (1:10 weight ratio). Was to be prepared.

Each of the prepared unvulcanized rubber sheets was cut to prepare a cutting sheet specimen (100 × 25 × 5 mm ³ ), and two prepared cutting sheets were adhered to each forming drum so that both ends were joined to form a tire tread. Made it.

Thermal plasma jets having outputs of 500 W, 800 W, 1,000 W, 1,500 W and 2,000 W were irradiated for 5 to 8 seconds on the cutting sheet joined at both ends, and then pressed to prepare adhesive specimens, respectively.

In addition, a cutting sheet specimen (100 × 25 × 5 mm ³ ) was prepared by cutting the same unvulcanized rubber sheet as in Examples 1 to 3, and the two prepared cutting sheets were each in close contact with a molding drum, and a cement-based adhesive was applied. It was applied so that both ends were joined.

As for the cement-based adhesive, in the case of a cutting sheet made of the first rubber compound, one containing 100 parts by weight of natural rubber (SVR CV60) was used (Comparative Example 1), and in the case of a cutting sheet made of the second rubber compound, natural rubber (SBR1502) 100 parts by weight, 20 parts by weight of alkyl phenolic resin, 5 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 50 parts by weight of carbon black, 5 parts by weight of paraffin, 2.6 parts by weight of sulfur, and a crosslinking accelerator ( A mixture containing 0.4 parts by weight of TBBS) was used (Comparative Example 2), and in the case of a cutting sheet made of a third rubber compound, one containing 100 parts by weight of natural rubber (VSL5025) was used (Comparative Example 3).

And, each unvulcanized specimen was prepared by applying a cement-based adhesive and reacting for 24 hours.

(2) Analysis of adhesive properties of adhesive specimens

The adhesion evaluation of the unvulcanized specimen was evaluated by applying the pressure sensitive adhesive (PSA) evaluation method Avery Adhesive Test. The evaluation method is to fix the adhesive specimen (100 × 25 × 5 mm ³ ) on the table of the adhesive tester using double-sided tape, and fix the other adhesive specimen (100 × 25 × 5 mm ³ ) to the upper probe, and then the probe is 0.05 mm. After descending at a rate of / second, the specimens were brought into contact with the cement coated surfaces for 10 seconds under a load of 500 g. After 10 seconds elapsed, the probe was raised at a speed of 10 mm/second, and the force generated when the adhesive surface fell off was measured, and the results of the adhesive property analysis are shown in Tables 2 and 3 below (adhesive strength unit: kg). .

As shown in Tables 2 and 3, it was confirmed that the adhesion properties of the unvulcanized specimens prepared by the methods according to Examples 1 to 3 increased as the output of the thermal plasma jet increased, and the thermal plasma of a specific output When the jet was irradiated, it was confirmed that the adhesive strength exhibited more improved properties compared to the cement-based adhesive.

Through the above results, it was confirmed that the adhesive properties of the unvulcanized specimen were improved in the case of the tire bonded by irradiating the thermal plasma jet compared to the case where the cement-based adhesive was applied.

(3) Analysis of adhesion properties of vulcanized adhesive specimens

Each of the adhesive specimens (Examples 1 to 3 and Comparative Examples 1 to 3) prepared in the vulcanization mold was supplied, heated to 160° C. under the condition of supplying vulcanization gas, and vulcanized under a load of 100 kgf for 20 minutes. Cured specimens were prepared.

Each vulcanized specimen prepared by performing a T-peel test, which measures the force when the adhesive interface is broken by biting the end of the adhesive specimen by a clamp and pulling it in the 180° direction using a universal testing machine. The adhesive strength was measured, and the results are shown in Tables 4 and 5. As for the test conditions, the adhesive strength (unit: kgf) was measured while cutting so that the adhesive interface was exposed using a knife in the center of the adhesive specimen that was opened when pulled at a speed of 500 mm/min.

As shown in Tables 4 and 5, as a result of analyzing the adhesion properties of the vulcanized specimens prepared by the methods according to Examples 1 to 3 and Comparative Examples 1 to 3, compared to the specimens of Comparative Examples 1 to 3 using a cement-based adhesive It was confirmed that the adhesive strength of the adhesive specimen prepared by irradiating the thermal plasma jet of a specific strength was higher, and it was confirmed that the adhesive strength after the vulcanization treatment could be further improved by irradiating the thermal plasma jet.

Through the above results, it was found that in the case of a tire bonded by irradiation with thermal plasma jet, the adhesive property of the unvulcanized specimen can be greatly improved and the adhesive property of the vulcanized specimen can be greatly improved compared to the case of applying a cement-based adhesive. I could confirm. In particular, it was also confirmed that the output of the thermal plasma jet to be irradiated has a great influence on the adhesion properties of the vulcanized specimen, so that it is better to change the output of the thermal plasma jet for each tire use.

Claims (7)

(a) Using a thermal plasma jet with an output of 500 to 3,000 W, the bonded surface of the cutting sheet for tire tread is heated and melted to bond the laminate including the cutting sheet for tire tread, and the bonded laminate is molded and drawn. Manufacturing a tire; And
(b) vulcanizing the green tire to manufacture a tire,
The thermal plasma jet,
A plasma torch for supplying a heat source for vaporizing plasma generation gas; A power supply unit provided on one side of the plasma torch unit to supply power; A reaction chamber provided below the plasma torch and providing a space for generating a thermal plasma jet; A plasma gas supply unit provided on one side of the plasma torch unit to supply plasma generation gas for generating a thermal plasma jet to the plasma torch unit, and a nozzle provided at one side of the reaction chamber unit to discharge the thermal plasma jet generation gas to the outside. A method of manufacturing a tire, characterized in that it is supplied using a thermal plasma supply device including a thermal plasma jet discharge unit. The method of claim 1,
The cutting sheet,
(1) forming a rubber compound to produce an unvulcanized rubber sheet;
(2) irradiating the surface of the unvulcanized rubber sheet with a thermal plasma jet to prevent surface oxidation of the unvulcanized rubber sheet; And
(3) manufacturing a cutting sheet by cutting the unvulcanized rubber sheet irradiated with plasma in step (2) to a preset length; including,
In the step (2), a method of manufacturing a tire, characterized in that irradiating a thermal plasma jet having an output of 100 to 1,500 W. The method of claim 1,
In the step (a), a thermal plasma jet having an output of 1,000 to 3,000 W is irradiated to the laminate to produce a green tire for manufacturing a truck bus radial (TBR tire). The method of claim 1,
In the step (a), a thermal plasma jet having an output of 1,000 to 2,500 W is irradiated to the laminate to produce a green tire for manufacturing a light truck radial (TBR tire). The method of claim 1,
In the step (a), a thermal plasma jet having an output of 1,000 to 2,500 W is irradiated to the laminate to produce a green tire for manufacturing a PCR tire (passenger car radial, PCR tire). delete A tire manufactured by the method according to any one of claims 1 to 5.

Images