KR101293468B1 - Curing bladder composition for tire and curing bladder manufactured by using the same - Google Patents

Abstract

The present invention relates to a rubber composition for tire vulcanizing bladder comprising 100 parts by weight of a raw material rubber including epoxidized natural rubber (ENR), 1.0 to 1.5 parts by weight of vulcanizing agent, and 3 to 6 parts by weight of vulcanization accelerator. It relates to a tire vulcanizing bladder manufactured from.
According to an embodiment of the present invention, by replacing ENR (Epoxidized Natural Rubber) without using butyl rubber, which constitutes the vulcanization bladder, it is not only excellent in various mechanical properties and thermal conductivity required for the vulcanization bladder, After use, biodegradable materials can provide environmentally friendly vulcanizing bladder.

Description

Cure bladder composition for tire and curing bladder manufactured by using the same}

The present invention relates to a vulcanizing bladder composition of a tire and a vulcanizing bladder manufactured using the same, in particular, a rubber composition for green tire vulcanizing bladder, which has improved environmental friendliness by changing the material of the raw rubber used in the bladder. And a vulcanization bladder prepared therefrom.

In general tire manufacturing, the green tires completed in the tire forming process are put into a vulcanization mold and vulcanized for a predetermined time under heat and pressure applied to the inside and outside of the green tires, thereby mixing the vulcanizing agent and rubber molecules mixed in the tire rubber compounding process. A vulcanization operation is performed to crosslink to obtain stable intrinsic properties of the tire rubber.

In the tire vulcanization operation, the green tire is closely adhered to the mold by installing a vulcanizing bladder inside the tire to supply heat and pressure to the inside of the tire and supplying steam and an inert gas to the vulcanizing bladder to expand the vulcanizing bladder.

At this time, steam of a constant pressure is supplied to the heating medium used in the vulcanizing bladder, and an inert gas is used as the pressurizing medium. As described above, the vulcanization method of supplying steam and inert gas into the vulcanization bladder has an economical advantage in terms of thermal efficiency, but for discharging it by generating condensed water by mixing hot steam with inert gas at room temperature. After condensate is discharged, condensate is generated by inert gas at room temperature, causing up and down temperature variations in tire green tires during vulcanization, resulting in deterioration of tire quality and deterioration of vulcanization bladder life.

Generally, the vulcanizer temperature is influenced by the mold temperature for vulcanizing the outside of the green tire and the temperature of the vulcanizing bladder vulcanizing the inside of the green tire, and the vulcanizing bladder temperature is the internal steam temperature and the vulcanizing bladder thermal conduction. Influenced by degrees.

In addition, the material of bladder is rubber and rubber is classified into natural rubber and synthetic rubber. Some newly developed synthetic rubbers are biodegradable, but most synthetic rubbers do not. Generally, the vulcanization bladder that transfers heat from the heat transfer medium to the green tire is poor in regeneration because the material is butyl rubber, which is a synthetic rubber.

In addition, the conventional vulcanization bladder solution is to add carbon nanotubes to the vulcanizing bladder made of butyl rubber instead of using carbon black or to reduce the thickness of the bladder and increase the number of vulnerable parts in order to increase the thermal conductivity than environmental considerations. The bars were used for reinforcement.

However, using only the material of the vulcanizing bladder as synthetic rubber has a problem that may adversely affect tire recycling and the environment.

Accordingly, the present invention is to solve the conventional problems as described above, while maintaining the air permeability and heat conductivity required for the vulcanization bladder at the same level as the conventional, while providing an environmentally friendly rubber composition for tire vulcanization bladder There is this.

In addition, another object of the present invention to provide a vulcanization bladder for environmentally friendly tires using the vulcanizing bladder composition.

In order to achieve the above object, the vulcanizing bladder composition according to an embodiment of the present invention is 100 parts by weight of the raw material rubber containing epoxidized natural rubber (ENR), 1.0 to 1.5 parts by weight of vulcanizing agent, and vulcanization It may include 3 to 6 parts by weight of the promoter.

The epoxidized natural rubber may be included in 80 to 100% by weight of the total raw rubber.

The epoxidized natural rubber is a rubber composition for tire vulcanizing bladder, characterized in that the air permeability is 10X10 ⁶ ~ 45X10 ⁶ cc · mm / m ² · atm · day (30 ° C.), and the thermal conductivity is 0.20W / m · K or more. .

The vulcanizing agent is a sulfur-based compound, the vulcanization accelerator may be any one selected from the group consisting of inorganic vulcanization accelerator, organic vulcanization accelerator, and combinations thereof.

In addition, in order to achieve the above object, the tire vulcanization bladder according to an embodiment of the present invention is manufactured using the rubber composition for tire vulcanization bladder.

According to an embodiment of the present invention, by replacing ENR (Epoxidized Natural Rubber) without using butyl rubber, which constitutes the vulcanizing bladder, it is not only excellent in various mechanical properties and thermal conductivity required for the vulcanizing bladder, After use, biodegradable materials can provide environmentally friendly vulcanizing bladder.

1 is a cross-sectional view showing a vulcanizing bladder and a green tire seated in a mold according to the present invention.

Hereinafter, with reference to the accompanying drawings the present invention will be described in more detail.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" include singular forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups.

The present invention relates to environmentally friendly bladder bladder compositions and tire vulcanization bladder produced therefrom while maintaining physical properties on an equivalent level to conventional levels.

1 shows the structure of the vulcanization bladder 1, the green tire 2 seated in the mold, and the tire vulcanization mold 3.

In the tire vulcanization operation, the green tire is closely adhered to the mold by installing a vulcanizing bladder inside the tire to supply heat and pressure to the inside of the tire and supplying steam and an inert gas to the vulcanizing bladder to expand the vulcanizing bladder. At this time, steam of a constant pressure is supplied to the heating medium used in the vulcanizing bladder, and an inert gas is used as the pressurizing medium.

Therefore, the biggest feature required for the rubber constituting the vulcanizing bladder is air permeability. The vulcanizing bladder plays a role of preventing the nitrogen gas, which is steam and inert gas, in the bladder from penetrating into the green tire. In addition, the vulcanizing bladder rubber can lead to improved tire productivity as it has higher thermal conductivity.

Therefore, butyl rubber has conventionally been used for the physical properties required for such vulcanizing bladder.

However, the present invention is characterized by using epoxidized natural rubber (ENR) as a rubber having air resistance similar to that of the butyl rubber and having high thermal conductivity. That is, the epoxidized vulcanization bladder deoyong rubber composition tire containing natural rubber is the air permeability ^{10X10 6 ~ 45X10 6 cc · mm} / m 2 · atm · day (30 ℃), preferably from 10X10 ⁶ ~ 34X10 ⁶ cc Mm / m ² · atm · day (30 ° C.), thermal conductivity is 0.20 W / m · K or higher, preferably 0.25 W / m · K or higher, and may have excellent air permeability and high thermal conductivity. have.

The epoxidized natural rubber may be used alone in the raw material rubber of the rubber composition for tire vulcanization bladder, or may be mixed with other natural rubber.

The epoxidized natural rubber may be included in 80 to 100% by weight of the total raw rubber, when the content of the epoxidized natural rubber in the raw material rubber is less than 80% by weight, air permeability increases, eco-friendly of the bladder for vulcanization This can be degraded.

The raw material rubber can be said that the use of natural rubber generally used together with the epoxidized natural rubber meets the object of the present invention for manufacturing environmentally friendly tire vulcanization bladder, the natural rubber is a general natural It may be rubber or modified natural rubber.

The above-mentioned general natural rubber may be used as long as it is known as natural rubber, and the country of origin and the like are not limited. The natural rubber includes cis-1,4-polyisoprene as a main component, but may also include trans-1,4-polyisoprene depending on required characteristics. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main component, natural rubber including trans-1,4-isoprene as a main component, such as balata, Rubber may also be included.

The modified natural rubber means that the general natural rubber is modified or purified. For example, the modified natural rubber may include deproteinized natural rubber (DPNR), hydrogenated natural rubber, and the like.

In addition, the rubber composition for tire vulcanization bladder of the present invention may be used a vulcanizing agent and a vulcanization accelerator for the crosslinking of the raw material rubber, the vulcanizing agent is included in 1.0 to 1.5 parts by weight based on 100 parts by weight of the raw material rubber. It is preferred for proper vulcanization of epoxidized natural rubber having the above properties.

The vulcanizing agent is preferably a sulfur-based vulcanizing agent, and the sulfur-based vulcanizing agent is inorganic vulcanizing agents such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S) and colloidal sulfur, and tetramethyl tea. Organic vulcanizing agents such as tetramethylthiuram disulfide (TMTD), tetraethyltriuram disulfide (TETD) and dithiodimorpholine can be used. Specifically, as the sulfur vulcanizing agent, a vulcanizing agent which produces elemental sulfur or sulfur, for example, amine disulfide, polymer sulfur, or the like can be used.

The vulcanization accelerator is a compounding agent used in combination with the vulcanizing agent to complete its promoting effect. Any one selected from the group consisting of inorganic vulcanization accelerators, organic vulcanization accelerators and combinations thereof may be used. .

As the inorganic vulcanization accelerating aid, any one selected from the group consisting of zinc oxide (ZnO), zinc carbonate, magnesium oxide (MgO), lead oxide, potassium hydroxide and combinations thereof may be used have. The organic vulcanization accelerator is selected from the group consisting of stearic acid, zinc stearate, palmitic acid, linoleic acid, oleic acid, lauric acid, dibutyl ammonium oleate, derivatives thereof, and combinations thereof. You can use either one.

In particular, the zinc oxide and the stearic acid may be used together as the vulcanization accelerator, in which case the zinc oxide is dissolved in the stearic acid to form an effective complex with the vulcanizing agent, thereby releasing advantageous sulfur during the vulcanization reaction. It facilitates the crosslinking reaction of the rubber.

When using the zinc oxide and the stearic acid together, it is preferably included 3 to 6 parts by weight based on 100 parts by weight of the raw material rubber for proper vulcanization of the epoxidized natural rubber having the above characteristics.

On the other hand, the present invention is also characterized in that it provides a tire vulcanizing bladder manufactured using the vulcanizing bladder composition.

The vulcanizing bladder according to the present invention can be used to produce environmentally friendly vulcanizing bladder by using epoxidized natural rubber which is biodegradable rubber as part or all of the raw material rubber, and various physical properties required for vulcanizing bladder It is more preferable because it can be maintained at the level of conventional butyl rubber.

Hereinafter, the present invention will be described in more detail with reference to Examples. The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, and the following examples can be modified in various other forms, and the scope of the present invention is It is not limited to an Example. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art.

<Comparative Example>

100 parts by weight of isoprene isobutyl rubber (IIR) was used as a raw material rubber and placed in a Banbery Mixer for 380 seconds at 150 ° C., 1.0 parts by weight of zinc oxide (ZnO), 0.5 parts by weight of stearic acid, and 0.5 parts by weight of sulfur was added to the Banbury Mixer (Banbery Mixer) was added for 50 seconds to prepare a rubber composition for tire vulcanization bladder.

&Lt; Example 1 >

10 parts by weight of natural rubber and 90 parts by weight of epoxidized natural rubber (ENR) were placed in a Banbery Mixer and blended at 150 ° C. for 380 seconds. 5.0 parts by weight of zinc oxide (ZnO) and stearic acid were added thereto. 1.0 parts by weight and 1.5 parts by weight of sulfur were further added to a Banbary Mixer and blended for 50 seconds to prepare a rubber composition for tire vulcanization bladder.

<Example 2>

100 parts by weight of epoxidized natural rubber (ENR) is used as a raw material rubber in a Banbery Mixer and blended at 150 ° C. for 380 seconds, followed by 2.0 parts by weight of zinc oxide (ZnO), 1.0 parts by weight of stearic acid, and 1.5 parts by weight of sulfur. The rubber composition for the tire vulcanization bladder was prepared by mixing in a Banbery Mixer for 50 seconds.

Specific rubber compositions of Examples and Comparative Examples are shown in Table 1 below. (Content: parts by weight)

Item Comparative example Example 1 Example 2 Isoprene Isobutyl Rubber (IIR) 100 - - Natural Rubber (NR) - 10 - Epoxidized Natural Rubber (ENR) - 90 100 Zinc oxide 1.0 5.0 2.0 Stearic acid 0.5 1.0 1.0 brimstone 0.5 1.5 1.5

<Test Example>

Physical properties and thermal conductivity such as hardness, 300% modulus, and tensile strength of the rubbers of Examples and Comparative Examples were measured according to ASTM-related regulations, and the results are shown in Table 2 below.

(1) Hardness is a value measured with a Shore A type durometer.

(2) Modulus (kgf / cm ² ) was measured by a tensile tester manufactured by Instron by cutting the specimen into a dumbbell. 300% modulus refers to the stress acting on a specimen when the specimen is stretched 300%.

(3) The elongation (%) was measured by the method of expressing the strain value in% after applying stress to the test specimen in the tensile tester.

(4) Tensile strength (Kgf / cm ² ) was measured by the method of ASTM D 790, the higher the value shows excellent strength.

(5) Toughness ((Kgf / cm ² ) X%) means the degree to which the specimen can withstand until the specimen breaks after stress.

(6) Thermal conductivity (W / mK, 25 ° C.) measured the thermal conductivity of each test piece, which was measured by a laser flash method.

(7) The air permeability (cc · mm / m ² · atm · day) was measured at 30 ° C. using a specimen having a diameter of 50 mm and a thickness of 250 μm.

Item Comparative example Example 1 Example 2 Hardness 43 40 55 300% modulus 28 33 98 Elongation rate 850 870 525 The tensile strength 70 179 219 tenacity 350 420 477 Thermal conductivity 0.25 0.25 0.25 Air permeability (X10 ⁶ ) 35 33 31

As in the result of Table 2, instead of the conventional butyl rubber in the present invention in the case of Examples 1 to 2 used as raw material rubber alone or mixed with natural rubber ENR, hardness, tensile strength, toughness, elongation It can be seen that the physical properties such as air permeability and the like are similar to those of the conventional comparative example using butyl rubber or rather increased.

In addition, the vulcanization bladder prepared using the composition of Examples 1 to 2 of the present invention can be confirmed that the thermal conductivity is also maintained at a similar level as in the prior art.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of right.

1: vulcanizing bladder
2: Green tire seated in mold
3: mold for tire vulcanization

Claims (5)

100 parts by weight of raw rubber including epoxidized natural rubber (ENR),
1.0 to 1.5 parts by weight of vulcanizing agent and
A rubber composition for tire vulcanization bladder comprising 3 to 6 parts by weight of vulcanization accelerator,
The epoxidized natural rubber is contained in 80 to 90% by weight of the total raw rubber,
The rubber composition for a tire vulcanizing bladder is a rubber composition for a tire vulcanizing bladder having an air permeability of ¹⁰ × ^{10 6} to 45 × 10 ⁶ cc · mm / m ² · atm · day (30 ° C.) and a thermal conductivity of 0.20 W / m · K or more. . delete delete The method of claim 1,
The vulcanizing agent is a sulfur compound,
The vulcanization accelerator is any one selected from the group consisting of inorganic vulcanization accelerator, organic vulcanization accelerator, and combinations thereof, rubber composition for tire vulcanization bladder. A tire vulcanizing bladder manufactured using the rubber composition for tire vulcanizing bladder according to any one of claims 1 and 4.

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