JP4404365B2 - Modification method of organic fiber cord - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for modifying an organic fiber cord (hereinafter, also simply referred to as “cord” and “modification method”), and more particularly, an organic fiber cord obtained by twisting an organic fiber into a cord. The present invention relates to a modification method for imparting appropriate physical properties and adhesion to rubber to an organic fiber cord used for reinforcement or the like.

  Organic fiber cords such as polyester and polyamide (nylon) used for reinforcing rubber articles such as tires are usually adhesives such as resorcin / formalin / rubber latex (RFL) liquid in order to ensure adhesion with rubber. After dipping in the liquid, it is modified by drying and heat treatment to give desired cord performance as a reinforcing cord.

  In the drying and heat treatment processes for the cord modification, conventionally, a method of exposing the organic fiber cord to a high temperature with hot air for a certain period of time under an appropriate tension is used so as to match the desired physical property for each fiber to be treated. It was done.

  However, the conventional method of reforming with hot air uses air with poor thermal conductivity as the heat medium, and heat treatment at high temperatures is required for fiber modification and bonding. It was. Therefore, (1) the processing speed cannot be increased in terms of efficiency, the productivity is restricted, and the fiber may be deteriorated due to an increase in processing time, and (2) production. Attempting to improve the performance would lead to an enormous size of the equipment, and there were various problems such as increased space, cost (equipment investment, processing costs, dip code), and increased amount of scrap (residence in the furnace) at the time of switching. . Therefore, there has been a demand for a modification technique that does not have such a problem and that can efficiently modify a cord in a short time, thereby obtaining a cord having a desired performance.

  Therefore, an object of the present invention is to improve the physical properties uniformly at a high speed, and therefore, it is possible to minimize the deterioration of the fiber during processing, and to have a desired cord characteristic. An object of the present invention is to provide a method for modifying an organic fiber cord, which can reliably and efficiently obtain a cord.

  As a result of intensive studies, the present inventors have found that a method using far infrared rays is effective in place of hot air in order to further improve the efficiency of heat treatment at such a high temperature. However, heating by far infrared rays is usually performed by heating a dichrome wire or the like embedded in a ceramic plate with a supply voltage, and there is a problem that the energy cost increases.

  From the above viewpoint, as a result of further examination, the present inventor directly arranged the ceramic plates on both sides of the cord in the heat treatment furnace, and further applied a method of circulating hot air, which is a conventional method, to directly apply the ceramic plates. Even without supplying voltage, it is possible to use far infrared rays generated by heating the ceramic plate with hot air heated to a predetermined temperature, which enables high-speed and high-efficiency reforming. It was possible to suppress the deterioration of the fiber during processing by shortening the heat treatment time, and it was found that the increase in energy cost associated with the use of far infrared rays could be suppressed, thereby completing the present invention. It was.

That is, the organic fiber cord modification method of the present invention is a method for modifying an organic fiber cord for reinforcing a tire in which organic fibers are twisted.
A dipping step of dipping the organic fiber cord into an adhesive; a drying step of drying the dipped organic fiber cord; and a heat treatment step of modifying the dried organic fiber cord, the heat treatment step comprising: Using a far-infrared treatment furnace equipped with a hot air generator and a ceramic plate, the dried organic fiber cord is irradiated with far-infrared rays.

  In the present invention, in the dipping step, it is preferable that the adhesive adhered to the organic fiber cord by dipping is sucked to adjust the adhesion amount of the adhesive to a constant amount.

  According to the modification method of the present invention, with the above-described configuration, it is possible to uniformly modify and bond the cord at a high speed and efficiently obtain a modified cord having desired cord characteristics. Became possible. Further, by suppressing fiber deterioration as much as possible by suppressing fiber deterioration, it is possible to obtain appropriate physical properties and adhesiveness in a short time for use as a reinforcing material for tires and the like. Specifically, desired cord basic physical properties, adhesiveness and durability can be obtained while shortening the heat treatment time to 1/8 to 3/4 of the conventional one. Furthermore, the present invention satisfies the demand for energy saving.

Hereinafter, preferred embodiments of the present invention will be described in detail.
FIG. 1A shows an organic fiber cord modification processing facility according to a preferred embodiment of the present invention. The present invention is an organic fiber cord formed by twisting organic fibers and is a method for modifying an organic fiber cord used for tire reinforcement or the like. As shown in the drawing, the organic fiber cord 10 is dipped in an adhesive. It includes a dipping step (A), a drying step (B) for drying the dipped organic fiber cord, and a heat treatment step (C) for modifying the dried organic fiber cord.

  In the present invention, it is important that the heat treatment step (C) is performed by irradiating the dried organic fiber cord with far infrared rays using a far infrared ray treatment furnace including a hot air generator and a ceramic plate. is there. By performing the heat treatment using far-infrared rays, it is possible to improve the adhesion reaction rate, which is the rate limiting of the heat treatment step, so that the time required for the treatment can be shortened to about 1/2 to 1/8 of the conventional time. In addition, it is possible to suppress a decrease in the cord physical properties due to the deterioration of the fibers at the time of processing, and at the same time, it is possible to reliably ensure desired adhesiveness suitable for tire reinforcement. Moreover, the problem of increase in energy costs can be solved by using a far-infrared treatment furnace including a hot air generator and a ceramic plate.

  An outline of the far infrared ray processing furnace 3 used in the present invention is shown in FIG. As shown in the figure, in the far-infrared processing furnace 3 according to the present invention, a ceramic plate 30 is disposed along the organic fiber cord 10 to be processed, and a hot air generator 40 is installed. Inside, for example, heated air is generated by gas combustion, and hot air is blown and circulated through the far-infrared treatment furnace 3 to perform the heat treatment step (C) in the present invention. In addition, the code | symbol 41 in a figure shows piping for hot air circulation.

The far-infrared processing furnace used in the present invention is not particularly limited with respect to the specifications other than the provision of a hot air generator and a ceramic plate, and a commercially available apparatus can be used as appropriate. As the material of the ceramic plate, commercially available far-infrared radiation ceramics can be used, but oxide ceramics such as alumina, beryllia, zirconia, magnesia, mullite, and forsterite are suitable.

  The far-infrared irradiation conditions are not particularly limited as long as the modification treatment can be appropriately performed, and can be set as desired. Further, at the time of processing, it is preferable to circulate the air together with a fan in order to warm the inside of the processing furnace to a predetermined temperature and to make the temperature distribution uniform and to improve the thermal efficiency.

  In the present invention, a predetermined effect can be obtained as long as the above conditions are satisfied for the heat treatment step (C). For example, in the dipping step (A), the organic fiber cord is formed by dipping. It is preferable to suck the adhered adhesive and adjust the adhesion amount of the adhesive to a certain amount. Specifically, the amount of adhesion is controlled by installing a vacuum device in the dip equipment, sucking the surface of the organic fiber cord after the dip, and removing the excessively adhered adhesive. Accordingly, by always attaching a certain amount of adhesive to the organic fiber cord in the dipping step (A), the cord is caused by local drying failure in the subsequent drying step (B) or the melting of the cord due to thermal drying. It is possible to prevent cutting and occurrence of processing unevenness in the heat treatment step (C). In particular, in the case of dipping processing of a single wire cord, since the amount of adhesion tends to be excessive, it is more effective to perform control using a vacuum device. In addition, there is no restriction | limiting in particular about a drying process (B), What is necessary is just to perform using the drying apparatus used conventionally suitably.

  The modification method of the present invention is particularly effective when modifying a single-wire cord having no weft as an organic fiber cord rather than a reed-like fabric, and according to the present invention, for example, 1 to 250 It is possible to modify about this number of single wire cords at the same time.

  The reforming method of the present invention is not particularly limited. For example, the reforming method can be performed using a reforming treatment facility having a configuration as shown in FIG. In the illustrated modification processing facility, an adhesive is applied to the organic fiber cord 10 unwound from the unwinding device 11 by dipping into the dip tank 1 through the pull roll 12 (dip process (A)). ) After adjusting the adhesive adhesion amount using the squeezing roll 13 and a vacuum device (not shown) as desired, drying is performed by the drying device 2 (drying step (B)). Next, the dried organic fiber cord 10 is heat-treated in the far-infrared treatment furnace 3 while being circulated through the pass roll 14 and the pull roll 12 (heat treatment step (C)), and this is wound up through the pull roll 12. It is wound up by the device 15. Thus, the modification | reformation code | cord | chord which has a desired code | cord | chord physical property can be obtained by performing a modification | reformation process, applying moderate tension | tensile_strength using a pull roll.

  In addition, especially as an organic fiber cord used as a process target in this invention, it does not restrict | limit, A various thing is applicable. As the fiber material, for example, polyamides such as nylon and aramid, polyesters such as polyethylene naphthalate (PEN), polyethylene terephthalate (PET), rayon, polyketone, vinylon, and the like that can be used for tire reinforcement or belt conveyors. All codes are applicable.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Example)
In the reforming treatment facility having the configuration shown in FIGS. 1A and 1B, the following apparatus and the heat treatment conditions (exposure time) shown in Tables 1 and 2 below are applied to modify the organic fiber cord. Quality treatment was performed.
Dip process (A): Dip tank 1
Drying step (B): Steam heating device 2
Heat treatment step (C): far-infrared treatment furnace 3 provided with a hot air generator, a circulation fan and a ceramic plate (see FIG. 1 (b), circulation fan not shown)

(Comparative example)
In the modification treatment facility having the same configuration as shown in FIG. 1A, the modification treatment of the organic fiber cord was performed using a gas heating furnace in the drying step (B) and the heat treatment step (C). Each treatment condition (temperature applied to the cord × exposure time (treatment time) × tension) was changed for each cord material, the drying step (B) and the two heat treatment steps (C) as shown below. The exposure time in the heat treatment step (C) was in accordance with the conditions shown in Tables 1 and 2 below.
In the case of PET: (drying step (B)) 160 ° C. × 40 seconds × 0.227 g / dtex, (heat treatment step (C)) 240 ° C. × 0.227 g / dtex
In the case of nylon 66: (drying step (B)) 140 ° C. × 60 seconds × 0.727 g / dtex, (heat treatment step (C)) 235 ° C. × 0.727 g / dtex

The physical properties of the modified cords obtained in each example and comparative example were evaluated according to the following. These results are also shown in Tables 1 and 2 below.
1) Elongation at constant load, breaking strength (dip cord intermediate elongation, dip cord strength)
In accordance with JIS L1017, the dip cord was pulled and tested with an autograph manufactured by Shimadzu Corporation to determine elongation (%) and breaking strength at a constant load of 2.02 g / dtex. As the denier of the cord used at this time, the positive fineness of JIS L1017 was used for the raw yarn.
2) Thermal contraction rate An initial load of 50 g was added to the dip cord and left in an oven at 177 ° C. for 30 minutes. The shrunken length was divided by the original length and expressed as a percentage.
3) Adhesive force The obtained dip coat was buried in rubber, vulcanized under a predetermined temperature and pressure, and then the force when pulled out from the rubber was used as the adhesive force. For each cord material, the result was expressed as an index with PET as Comparative Example 1 and Nylon 66 as Comparative Example 3. The higher the number, the better the result.

In each example and comparative example, the following two types of twisted cords were used. The intermediate elongation, strength, and heat shrinkage rate of each twisted cord were measured in the same manner as the dip cord. Further, as the adhesive liquid, an RFL adhesive liquid usually used for tire reinforcing cords was used.
Examples 1 and 2 and Comparative Examples 1 and 2
PET: 1670 dtex, (twisted structure (both top and bottom)) 1670 dtex / 2, number of twists 39 times / 10 cm, (twisted cord strength) 238N, (intermediate elongation at twisted cord 66N load) 11.8%, (heat shrinkage rate) ) 7.0% (In order to obtain the results clearly, a pretreated PET yarn that was previously surface-modified with an epoxy compound as a pretreatment was used.)
Examples 3 and 4 and Comparative Examples 3 and 4
Nylon 66: 1400 dtex, (twisted structure (both top and bottom)) 1400 dtex / 2, number of twists 39 times / 10 cm, (twisted cord strength) 235N, (intermediate elongation when twisted cord 66N is loaded) 12.1%, (heat shrinkage) Rate) 8.0%

  As can be seen from the results in Tables 1 and 2 above, in the modified cords of the examples in which the heat treatment process was performed using the far-infrared irradiation device including the hot air generator and the ceramic plate, both were compared with the comparative examples. It was confirmed that excellent adhesion was obtained.

(A) is the schematic which shows the structure of the modification | reformation processing equipment of the organic fiber cord which concerns on one suitable embodiment of this invention, (b) is a schematic explanatory drawing which shows the outline | summary of the far-infrared processing furnace which concerns on this invention. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dip tank 2 Drying apparatus 3 Far-infrared processing furnace 11 Unwinding apparatus 10 Organic fiber cord 12 Pull roll 13 Drawing roll 14 Pass roll 15 Winding apparatus 30 Ceramic board 40 Hot-air generator 41 Piping for hot-air circulation

Claims (2)

In a method for modifying an organic fiber cord for reinforcing a tire formed by twisting an organic fiber,
A dipping step of dipping the organic fiber cord into an adhesive; a drying step of drying the dipped organic fiber cord; and a heat treatment step of modifying the dried organic fiber cord, the heat treatment step comprising: A method for modifying an organic fiber cord, which is performed by irradiating the dried organic fiber cord with far infrared rays using a far infrared treatment furnace comprising a hot air generator and a ceramic plate.   The method for modifying an organic fiber cord according to claim 1, wherein, in the dipping step, the adhesive attached to the organic fiber cord by dipping is sucked to adjust the adhesion amount of the adhesive to a constant amount.

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