KR100674673B1 - High performance radial tire using hybrid cord - Google Patents

Abstract

The present invention is to produce a twisted yarn by giving twist of the same softener and different softeners to polyethylene naphthalate yarn and polyhexamethylene adipamide yarn, and the lower twisted yarn is plyed in three to add the upper twisted yarn to produce a raw cord It provides a hybrid deep cord for the radial tire excellent in the high utilization rate produced by the step, the method comprising the step of immersing the raw cord in a dipping liquid.

In addition, the present invention relates to a radial pneumatic tire having a flatness of 0.65 or less, comprising: a pair of parallel bead cores and at least one radial carcass ply wound around the bead core and a belt stacked on the outer circumferential side of the carcass. And a circumferential belt reinforcement layer formed on an outer circumferential side of the belt layer, wherein the belt reinforcement layer is directed to a radial pneumatic tire comprising a hybrid deep cord made of polyethylene naphthalate yarn and polyhexamethyleneadipamide yarn.

Hybrid, Capply, Belt Reinforcement Layer, Polyhexamethyleneadipamide, Polyethylenenaphthalate, Handleability, Radial Tire, Shape Stability

Description

High performance radial tire using hybrid cord             

Figure 1 is an example schematically showing the spinning process of polyethylene naphthalate or polyhexamethyleneadipamide according to the present invention.

Figure 2 is an example schematically showing the structure of a tire for a passenger car manufactured using the polyethylene naphthalate and polyhexamethyleneadipamide hybrid cord according to the present invention in a cap fly cord.

※ Brief description of the main symbols in the drawing

31: tire 32: carcass layer

33: code for reinforcing the carcass layer 34: fly turn-up

35: bead area 36: bead core

37: Bead Filler 38: Belt Structure

39: cap fly 40: belt fly

41, 42: belt code 43: tread

44: edge fly 45: cap fly code

In recent years, the performance of tires has been continuously improved according to the improvement of the road environment and the performance of the vehicle, and in particular, it is recognized that safety is more important as the quality of the tire as the weight of the vehicle increases and the limit speed increases. In line with the demand for increasing tire safety, tire safety standards are also changing, and the tire industry is actively researching methods for providing tire safety.

A method of imparting a cap fly to a tire for a passenger car has also been widely used as one of the methods for imparting safety to a tire. In particular, in recent years, a tire having such a cap fly has been generalized and widely applied. CapFlye is a part that maintains the shape stability of tires by continuously winding between tire tread and steel cord layer for reinforcing belt in the circumferential direction of tire. It is common to be reinforced. When the vehicle is running, a load is applied in the axial direction of the tire cord, and the tire cord is repeatedly deformed and recovered in the axial direction by this load, and in this deformation-recovery, the tension-load at the time of deformation and recovery. There is a difference in the curve, where the work loss of the tire cord itself occurs due to the deformation of the tensile load and the difference of the recovery curve when the load is removed. This work loss contributes to the temperature rise of the tire and the tire cord. In addition, the work loss causes energy loss while the tire rotates, resulting in energy loss while driving. This energy loss leads to the rolling resistance of the vehicle, and in general, when using materials having high energy loss characteristics, the fuel efficiency of the vehicle is increased due to the increased rolling resistance of the tire and the temperature of the tire is increased due to driving. do. The role of the cap ply material is to prevent the size of the tire from increasing while the cap ply contracts when the temperature of the tire increases due to the driving of the vehicle. In such a case, since the tire does not increase in size, an increase in tire rotational inertia is prevented. As a result, an increase in fatigue life and an increase in durability can be imparted to the tire by suppressing heat generation of the tire along with a decrease in energy consumption.

In general, the most widely used material for capply material is polyhexamethyleneadipamide, which is known to be due to the high shrinkage force of polyhexamethyleneadipamide. The part where the cap ply reinforces is known as the part with the highest temperature while driving on the tire. In addition to the heat shrinkage force, a material having a low heat resistance, that is, a property deterioration due to heat, is required. Substances must be used. Polyhexamethyleneadipamide is the material used for tire cords with these properties. Although research is being carried out to apply to cap plies using other materials such as polyethylene terephthalate (PET), these materials are weak to heat, and in particular, there is a limitation in that they are applied to cap plies due to a large decrease in adhesive strength due to heat.                         

Other materials used in the cap ply are aramid and the like, but the use of aramid has a different feature from that of using polyhexamethyleneadipamide. Aramid fibers are aromatic polyamide fibers, which are polyamide fibers having a benzene ring in a repeating unit. It is a material that shows stable physical properties even at high temperatures, and when applied to a tire cap ply, it cannot be expected to develop shrinkage at high temperatures, but the deformation itself is suppressed at very high temperatures so that the deformation itself is suppressed and thus the polyhexamethyleneadipamide cap ply is used. It has a characteristic similar to that of the applied result. Therefore, although the use of such aramid fibers is also increasing, in the case of aramid fibers, there is a problem of low fatigue resistance, the price is very expensive, there is a problem that is limited to use.

Accordingly, the present invention has been invented to solve the above problems, the object of the present invention is to apply to the cap ply (belt reinforcement layer) of pneumatic radial tires for passenger cars, polyethylene naphthalate and polyhexamethylene adipamide It is to provide a hybrid deep cord and a radial tire using the same to give a twist of each different number of years to produce a lower twist yarn, and the upper twist yarn is added to three by adding the upper twist yarn.

In order to achieve the above object, the present invention provides a cap fly cord for a passenger car tire through the following processes.

As a preliminary step for producing a hybrid cap fly cord in the present invention, polyethylene naphthalate yarn and polyhexamethyleneadipamide yarn are prepared using the following process.

Hereinafter, the manufacturing process of the polyethylene naphthalate fiber of the present invention will be described step by step.

First, the polyethylene naphthalate polymer used in the present invention contains at least 85 mol% of ethylene-2,6-naphthalate units, and preferably consists only of ethylene-2,6-naphthalate units.

Optionally, the polyethylene-2,6-naphthalate may incorporate as a copolymer unit a small amount of units derived from one or more ester-forming components other than ethylene glycol and 2,6-naphthalene dicarboxylic acid or derivatives thereof. Can be. Examples of other ester forming components copolymerizable with polyethylene naphthalate units include glycols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, and the like, terephthalic acid, isophthalic acid, hexahydroterephthalic acid, stilbene Dicarboxylic acids such as dicarboxylic acid, bibenzoic acid, adipic acid, sebacic acid, azelaic acid.

The polyethylene naphthalate chip according to the present invention preferably melt-mixes naphthalene-2,6-dimethylcarboxylate (NDC) and ethylene glycol raw materials at 190 ° C. at a ratio of 2.0 to 2.3 and transesterifies the melted mixture. Reaction (for about 2 to 3 hours at 220 to 230 ° C.) and polycondensation reaction (for about 2 to 3 hours at 280 to 290 ° C.) to form raw chips having an intrinsic viscosity of 0.42 or more, and then 240 to It is solid phase polymerized to have an intrinsic viscosity of 0.80 to 1.20 and a moisture content of 30 ppm or less under a temperature of 260 ° C and a vacuum.

In the present invention, optionally, during the transesterification reaction, as a transesterification catalyst, a manganese compound, preferably manganese acetate, may be added in an amount such that the remaining amount of manganese metal in the final polymer is 30 to 70 ppm. If it is less than 30 ppm, the rate of transesterification is too slow, and if it is more than 70 ppm, more manganese metal is required as a foreign matter, which is a problem in solid state polymerization and spinning.

In the present invention, optionally, during the polycondensation reaction, as a polymerization catalyst, an antimony compound, preferably antimony trioxide, may be added in an amount such that the amount remaining as an antimony metal in the final polymer is from 180 to 300 ppm. When less, the polymerization reaction rate is lowered and the polymerization efficiency is lowered. When the amount is higher than 300 ppm, more than necessary antimony metal acts as a foreign material, which degrades radio-stretching workability. In this case, a phosphorus heat stabilizer, preferably trimethyl phosphate, may be added in an amount such that the remaining amount of phosphorus element in the final polymer is 35 to 45 ppm, and the manganese / phosphorus content ratio is 2.0 or less. When the manganese / phosphorus content ratio is higher than 2.0, the oxidation is promoted during the solid phase polymerization, so that normal physical properties cannot be obtained during spinning.

The polyethylene naphthalate chip thus produced is fiberized according to the method of the present invention, and FIG. 1 schematically shows a manufacturing process according to one embodiment of this invention.

First, the polyethylene naphthalate chip is passed through the pack 1 and the nozzle 2, preferably at a spinning temperature of 290 to 328 ° C., preferably at a spinning draft ratio of 20 to 200 (linear velocity / nozzle on the first winding roller). The low-temperature melt spinning at the linear velocity at can reduce the viscosity of the polymer due to thermal decomposition and hydrolysis. If the spinning draft ratio is less than 20, the uniformity of the filament cross section worsens, and the drawing workability is significantly lowered. If it exceeds 200, the filament breakage occurs during spinning, making it difficult to produce a normal yarn.

The melt-discharged yarn 4, prepared as described above, is quenched by passing through the cooling zone 3, if necessary, a distance from the nozzle 2 directly below the starting point of the cooling zone 3, i.e. A short heating device may be installed in the length (L) section.

This zone is called delayed cooling zone or heating zone, which has a length of 50 to 250 mm and a temperature of 250 to 400 ° C. (air contact surface temperature).

In the cooling zone 3, an open quenching method, a circular closed quenching method, and a radial outflow quenching method may be applied depending on a method of blowing cooling air. It is not limited to. Subsequently, the discharged yarn 4 solidified while passing through the cooling zone 3 can be oiled by the emulsion applying device 5 to 0.5 to 1.0%.

The solid discharged yarn 4 is drawn through a series of drawing rollers 6, 7, 8, 9 and 10 by spin draw, while drawing at a total draw ratio of at least 4.0 times, preferably 4.5 to 6.5. The drawing company 11 is obtained.

While narrowing the distance between the nozzle and the top of the cooling section as possible during spinning, it is advantageous to have high strength in the final stretch yarn, but during spinning, the distance from the nozzle to the bottom of the heating device is less than 50 mm (actually the length directly under the nozzle Since there is a radial block of about 50mm, the distance from the bottom of the heater to the bottom of the heater is 100mm when using a heater of 50mm in length. Or, if the distance between the bottom of the heater and the top of the cooling device is 50 to 150mm, it is not drawn. The nonuniformity of is generated to a considerable extent, and drawing of normal physical properties becomes impossible.

Stretched polyethylene naphthalate fibers produced according to the process of the invention have an intrinsic viscosity of 0.60 to 0.90, strength of at least 8.5 g / d, elongation of at least 6.0% and shrinkage of 1 to 4%, fineness of 500 to 2000 denier.

In addition, in the present invention, as a preliminary step for producing a hybrid cap fly cord, the production of polyhexamethyleneadipamide is prepared using the following process. Hereinafter, the manufacturing process of the polyhexamethylene adipamide company of this invention is demonstrated step by step.

The polyhexamethyleneadipamide polymer used in the present invention contains at least 85 mol% of hexamethyleneadipamide repeating units, and preferably consists of only hexamethyleneadipamide units.

Alternatively, any polyamide homopolymer and copolymer can be used in place of the polyhexamethyleneadipamide. Such polyamides are mainly aliphatic. Poly (hexamethylene adipamide) (nylon 66); Poly (ε-caproamide) (nylon 6); And widely used nylon polymers such as copolymers thereof. Nylon 66 is most preferred. Other nylon polymers that can be advantageously used are nylon 12, nylon 46, nylon 6 · 10 and nylon 6 · 12.

The polyhexamethyleneadipamide chip according to the present invention may be added in an amount such that the residual amount of copper metal in the final polymer is 20 to 50 ppm in order to improve thermal stability. Pyrolysis occurs due to poor thermal stability, and when it is more than 50 ppm, more than necessary copper metal acts as a foreign matter, which is a problem in spinning.

The polyhexamethyleneadipamide chip is fiberized according to the method of the present invention, and FIG. 1 schematically illustrates a manufacturing process according to one embodiment of this invention.

First, the polyhexamethyleneadipamide chip is passed through a pack (1) and a nozzle (2) at a spinning temperature of preferably 270 to 310 DEG C, preferably a spinning draft ratio of 20 to 200 (line on the first winding roller). By melt-spinning at a low temperature at a velocity / linear velocity), it is possible to prevent a decrease in the viscosity of the polymer due to thermal decomposition. If the draft ratio is less than 20, the uniformity of the cross section of the filament becomes worse, and the drawing workability is significantly lowered. If it exceeds 200, the filament breakage occurs during spinning, making it difficult to produce normal yarn.

In addition, in this invention, it is an important factor to adjust the filtration residence time in a pack to 3-30 second. If the filtration residence time in the pack is less than 3 seconds, the filtration effect of the foreign matter is insufficient, and if it is more than 30 seconds, pyrolysis is severe due to excessive pack pressure increase.

In addition, in the present invention, it is preferable to set the L / D (length / diameter) of the extruder screw to 10 to 40, which is difficult to uniformly melt when the L / D of the screw is less than 10, and that the excessive shear stress exceeds 40. Molecular weight fall is severe and physical property is inferior.

The melt discharged yarn 4 of step (A), prepared as described above, is quenched through a cooling zone 3.

In the cooling zone 3, an open quenching method, a circular closed quenching method, and a radial outflow quenching method may be applied depending on a method of blowing cooling air. Open quenching is preferred. Subsequently, the discharged yarn 4 solidified while passing through the cooling zone 3 can be oiled by the emulsion applying device 5 to 0.5 to 1.0%. The preferred spinning speed of the undrawn yarn is 200 to 1,000 m / min.

The final stretched yarn 11 is drawn by passing the unstretched yarn at a draw ratio of at least 4.0 times, preferably 4.5 to 6.5, while passing through the series of draw rollers 6, 7, 8, 9 and 10 by a spin draw method. Get)

The polyhexamethyleneadipamide stretched yarn of the present invention stabilizes the crystal structure in the heat treatment step after the two-stage stretching step. The multi-stage stretching process of the present invention consists of a primary stretching process proceeding at a high stretching ratio at a low stretching temperature and a secondary stretching process proceeding at a relatively low stretching ratio at a high temperature. In the primary stretching step of the present invention, crystallization mainly due to orientation proceeds. The preferred stretching temperature in the primary stretching process of the present invention is 20 to 50 ℃, the stretching ratio is 3.0 times or more, it is difficult to manage the stretching temperature is less than 20 ℃ without installing an additional cooling device in the stretching roller in the process. It is difficult and economically disadvantageous, and when the stretching temperature exceeds 50 ° C, crystallization by heat proceeds. Moreover, when the draw ratio is less than 3.0 times, sufficient orientation crystallization hardly occurs.

In the secondary stretching step of the present invention, crystallization by heat proceeds at a high temperature. In the secondary stretching step of the present invention, the preferred stretching temperature is 200 to 250 ° C, and the draw ratio is 2.0 times or less. If the stretching temperature is less than 200 ° C, sufficient crystallization by heat does not proceed, and the stretching temperature exceeds 250 ° C. It causes damage to the yarn. In addition, when the draw ratio exceeds 2.0 times, the elongation of the yarn decreases drastically.

Polyhexamethyleneamide fibers produced according to the process of the invention have a strength of at least 9.0 g / d, at least 10% elongation, and 500 to 2000 denier.

In the present invention, in producing a hybrid cord using polyethylene naphthalate yarn and polyhexamethylene adipamide yarn prepared through the process as described above, the step of imparting a twist to the cord as a preliminary step of the deep cord production (twisting step) Will go through.

The raw cord manufactured according to the method of the present invention is composed of two nylon 66 yarns and one PEN yarn, or one nylon 66 yarn and two PEN yarns. It consists of four. At this time, Ply Twist is added to Polyhexamethyleneadipamide and Polyethylenenaphthalate, followed by the addition of Cable Twist, which is generally manufactured. Will be added.

In the present invention, it is possible to give different years of training according to the elongation of the yarn. The twist number imparted to the polyhexamethyleneadipamide yarn and the polyethylenenaphthalate yarn is preferably 1: 1 to 2. It improves the breaking elongation of polyethylenenaphthalate in the raw cord by controlling the final twist number (twist after the lower edge is added) to the low-strength polyethylenenaphthalate yarn, thereby increasing the polyhexamethyleneadipamide yarn and polyethylene. This is because the difference in cutting elongation of naphthalate can be minimized, thereby improving the strong utilization of raw code.

In the present invention, the properties of the cords such as elongation, stiffness, fatigue resistance, etc. are changed depending on the level (year) of twisting applied to the polyhexamethyleneadipamide and polyethylenenaphthalate yarns. In general, when the twist is high, the strength decreases, and the trunk and the body tend to increase. In addition, fatigue fatigue tends to improve with increasing twist. The number of years of hybrid tire cords produced in the present invention was made of 250/250 TPM to 500/500 TPM at the same time as the upper and lower edges, but giving the same upper and lower edges to the same value indicates that the manufactured tire cords do not show rotation or twist. It is to maximize physical expression by making it easy to maintain a straight line without. At this time, if less than 250/250 TPM, the extension of the raw cord is reduced, fatigue fatigue is easy to fall, and if it exceeds 500/500 TPM, the strong degradation is large, it is not suitable for the tire cord.

In addition, in the present invention, if the number of years of upper and lower smoke is given differently, in this case, the upper lead is adjusted to 350TPM to 550TPM, and the lower lead is adjusted to 300TPM to 550TPM, so that the upper and lower lead is different from each other. Produced. The reason why the upper and lower stations are differently produced is that the lower the number of stations within the optimum properties of the raw cord, the lower the cost of the yarn and the more the economic benefits.

Raw cord is manufactured using a weaving machine, and the obtained fabric is immersed in a dipping solution, and then cured to produce a tire cord having a resin layer attached to the surface of the 'raw cord'. Make a 'Dip Cord'.

In more detail, the dipping process of the present invention, dipping is achieved by impregnating a surface of the fiber with a resin layer called RFL (Resorcinol-Formaline-Latex), which is a disadvantage of the fibers for tire cords, which are inherently poor in adhesion to rubber. Is carried out to improve.

In the present invention, as an example of the adhesive liquid for the adhesion of the hybrid cord and rubber can be prepared and used using the following method. The examples described below are only intended to more clearly understand the present invention and are not intended to limit the scope of the present invention.

29.4 wt% Resorcinol 45.6 parts by weight

Pure 255.5 parts by weight                     

37% formalin 20 parts by weight

10 wt% sodium hydroxide 3.8 parts by weight

After preparing the solution, the reaction was stirred at 25 ° C. for 5 hours, and then the following components were added.

40wt% VP-latex 300 parts by weight

129 parts by weight pure

23.8 parts by weight of 28% aqueous ammonia

After the ingredient is added, the mixture is aged at 25 ° C. for 20 hours to maintain a solid concentration of 19.05%.

After the drying, the adhesive liquid is imparted, but in order to adjust the adhesion amount of the adhesive liquid, it is preferable to add a stretch of 0 to 3%, and more preferably to apply a stretch of 1 to 2%. If the stretch is too high, the adhesion amount of the adhesive liquid can be controlled, but the result is a decrease in the elongation, which results in a decrease in fatigue resistance. If the stretch is too low, for example, if it is lowered below 0%, the poly Dipping liquid penetrates into the hexamethyleneadipamide cord, making it impossible to control the DPU.

The adhesive amount is preferably 4 to 6% by weight of the fiber based on the solid content. After passing through the adhesive liquid, it is dried at 120 to 150 ℃. Drying is performed for 180 seconds to 220 seconds, and it is important to dry the cord with a stretch of about 1 to 2% applied to the cord. In the case of lack of stretch, the cord's middle body and extension increase, which leads to insufficient physical properties to apply to the tire cord. When the stretch is over 3%, the middle body level is appropriate but the body's length is too low. Will occur.

After drying, heat treatment is performed in a temperature range of 130 to 170 ° C. Stretch during heat treatment is maintained between -2 to 0%, the heat treatment time is appropriate 50 seconds to 90 seconds. If the heat treatment is less than 50 seconds, the reaction time of the adhesive liquid is insufficient, resulting in low adhesive strength. If the heat treatment is longer than 90 seconds, the hardness of the adhesive liquid is increased, resulting in a decrease in fatigue resistance of the cord. Will be imported.

In the present invention, using the manufactured deep cord as a cap ply, a tire for a passenger car is manufactured.

Figure 2 schematically shows the structure of a tire for a passenger car manufactured using the hybrid deep cord according to the present invention as a cap ply.

Hereinafter, FIG. 2 will be described in more detail as follows.

The bead regions 35 of the tire 31 each have an annular bead core 36 which is inextensible. The bead core is preferably made of single or multiple filament steel wires wound in series. In a preferred embodiment, high strength steel wires of 0.95 mm-1.00 mm diameter form a 4x4 structure, and it is also possible to form a 4x5 structure.

In a particular embodiment of the invention, the bead region also has a bead filler 37, in the case of the bead filler, it is necessary to have a hardness of at least a certain level, preferably Shore A hardness of 40 or more. Is preferred.

In the present invention, the tire 31 is reinforced by the crown portion by the belt structure 38 and the cap fly 39 structure. The belt structure 38 comprises two cutting belt plies 40 and the belt cords 41 of the belt plies are oriented at an angle of about 20 ° with respect to the circumferential central surface of the tire. The belt cord 41 of the belt ply is disposed opposite to the direction of the belt cord 42 of the other belt ply in a direction opposite to the circumferential center surface. However, the belt structure 38 may comprise any number of plies and may preferably be arranged in the range of 16-24 °. The belt structure 38 serves to provide lateral stiffness to minimize the rise of the tread 43 from the road surface during operation of the tire 31. The belt cords 41 and 42 of the belt structure 38 are made of steel cords and have a 2 + 2 structure, but can be manufactured in any structure. The cap ply 39 and the edge ply 44 are reinforced on the upper portion of the belt structure 38. The cap ply cord 45 in the cap ply 39 is reinforced in parallel to the circumferential direction of the tire to prevent high speed rotation of the tire. The capfly cord 45 serves to suppress the size change in the circumferential direction, and has a large heat shrinkage stress at a high temperature. The cap fly cord uses a hybrid deep cord made of polyethylenenaphthalate and polyhexamethyleneadipamide, which are prepared according to the method of the present invention. One layer of cap ply 39 and one layer of edge ply 44 may be used, but preferably, 1-2 layers of cap ply and 1-2 layers of edge ply are reinforced.

Hereinafter, the structure and effect of the present invention will be described in more detail with specific examples and comparative examples, but these examples are only intended to more clearly understand the present invention, and are not intended to limit the scope of the present invention. In Examples and Comparative Examples, properties of the tire cord and the like were evaluated in the following manner.

(a) Hybrid Tire Cord Strength (kgf) and Medium Elongation (%)

After drying at 107 ° C. for 2 hours, an Instron low speed tensile tester was used. After twisting at 80 Tpm (80 twist / m), the sample was measured at 250 mm and a tensile rate of 200 m / min. In this case, the elongation at specific load is measured by applying a load of 4.5 g per denier to the yarn.

(b) Dry heat shrinkage (%, Shrinkage)

After drying for 24 hours at 25 ° C and 65% RH, dry heat shrinkage was determined using the ratio of the length (L ₀ ) measured at 20g static load and the length (L ₁ ) after treatment at 20g static load for 30 minutes at 150 ° C. Obtain

S (%) = (L ₀ -L ₁ ) / L ₀ × 100

(c) Hybrid deep code E-S value

Elongation under a constant load is referred to as the middle elongation (E) in the present invention, 'S' means the dry heat shrinkage of the above (b), the sum of the intermediate elongation (E) and dry heat shrinkage (S) is called 'ES'. In this invention, it is called.

ES = median elongation (%) + dry heat shrinkage (%)

(d) even with fatigue

The fatigue strength of the tire cord was measured using a Goodrich Disc Fatigue Tester, which is commonly used for fatigue testing of tire cords, and fatigue resistance was compared. The fatigue test conditions were 120 ° C., 2500 RPM, 10% compression and 18% compression. After fatigue testing, the rubber was swelled by immersion in tetrachloroethylene solution for 24 hours, and the rubber and cord were separated to measure residual strength. The residual strength was measured after drying at 107 ° C. for 2 hours using a conventional tensile strength tester according to the method (a) above.

(e) adhesion

H-test was performed to measure the initial adhesion of the hybrid dip cord to the rubber. H-test ensures that both ends of the deep cord are embedded in 9.5mm rubber lumps, and the gap between the rubber lumps at both ends is kept at 9mm and the rubber is pulled on both sides to measure the maximum load at which the rubber-cord separation occurs. How to evaluate. In addition, sufficient strength is given to a rubber | gum by measuring at 20 degreeC and the pressure of 25 kg / cm <^2> for 20 minutes, before adhesive force evaluation. The rubber composition used for the test was 100 parts of natural rubber, 3 parts of zinc oxide, 28.9 parts of carbon black, 2 parts of stearic acid, 7.0 parts of pintar, 1.25 parts of MBTS, 3 parts of sulfur, 0.15 parts of diphenyl guanidine and phenylbeta naphthylamine 1.0 part is mix | blended.

Example 1

Polyethylene naphthalate and polyhexamethyleneadipamide fibers were obtained in the same manner as described above to prepare the fibers for tire reinforcement. Two twisted yarns were prepared by applying different twists of 440TPM and 470TPM to two polyhexamethyleneadipamide yarns (840D) and one polyethylenenaphthalate yarn (1000D), respectively, and the three twisted yarns were plywooded Was added to the 470TPM staging to prepare a raw code.

The resulting hybrid raw cord was dried at 100 ° C. for 130 seconds, and then passed through an adhesive liquid prepared by the following method to give an adhesive liquid. During drying, 2% of stretch was added to prevent non-uniformity of raw cords due to heat shrinkage.

29.4 wt% Resorcinol 45.6 parts by weight

Pure 255.5 parts by weight

37% formalin 20 parts by weight

10 wt% sodium hydroxide 3.8 parts by weight

After preparing the solution, the reaction was stirred at 25 ° C. for 5 hours, and then the following components were added.

40wt% VP-latex 300 parts by weight

129 parts by weight pure

23.8 parts by weight of 28% aqueous ammonia                     

After the ingredient is added, the mixture is aged at 25 ° C. for 20 hours to maintain a solid concentration of 19.05%.

After giving an adhesive liquid, it dried for 2 minutes at 150 degreeC, and heat-processed for 1 minute at 170 degreeC, and the adhesive process was complete | finished. Table 1 shows the physical properties of the dip cord thus prepared.

Example 2

The lower twisted yarn was prepared by applying different twists of 440TPM and 470TPM to one polyhexamethyleneadipamide (840D) and two polyethylenenaphthalate yarns (1000D), respectively. It was prepared as raw code by adding staging at 470 TPM.

The obtained polyhexamethylene adiamide raw cord was dried at 100 ° C. for 120 seconds, and then passed through an adhesive liquid prepared by the following method to give an adhesive liquid. During drying, 1% of stretch was added to prevent non-uniformity of raw cords due to heat shrinkage.

29.4 wt% Resorcinol 45.6 parts by weight

Pure 255.5 parts by weight

37% formalin 20 parts by weight

10 wt% sodium hydroxide 3.8 parts by weight

After preparing the solution, the reaction was stirred at 25 ° C. for 5 hours, and then the following components were added.

40wt% VP-latex 300 parts by weight

129 parts by weight pure

23.8 parts by weight of 28% aqueous ammonia

After the ingredient is added, the mixture is aged at 25 ° C. for 20 hours to maintain a solid concentration of 19.05%.

After giving an adhesive liquid, it dried for 180 second at 150 degreeC, and heat-processed for 90 second at 170 degreeC, and the adhesive process was complete | finished. Table 1 shows the physical properties of the dip cord thus prepared.

Comparative Example 1

A raw cord and a treatment cord were prepared by performing the same experiment as in Example 1 except that the polyethylene naphthalate yarn was twisted in 1000 denier / 2 sum. Table 1 shows the physical properties of the dip cord thus prepared.

Comparative Example 2

Except that the polyhexamethyleneadipamide yarn was twisted in 840 denier / double sum, the experiment was carried out in the same manner as in Example 1 to prepare a live cord and a treated cord. Table 1 shows the physical properties of the dip cord thus prepared.

Table 1

division Treatment Code Properties Strong (kg) Medium Elongation (%) Shrinkage (%) E _2.25 + FS (%) Fatigue resistance (%) Adhesion to rubber (kg) Example 1 21.0 7.9 1.4 9.3 89 15.4. Example 2 21.6 5.0 1.6 6.6 87 12.4 Comparative Example 1 16.1 2.3 1.0 3.3 79 9.1 Comparative Example 2 16.0 10.5 2.0 12.5 90 16.5

As a result of the test results of Table 1, in comparison with similar fineness standards, in the case of the hybrid deep cord according to the present invention (Example 2), the adhesive strength is significantly improved compared to the deep cord (Comparative Example 1) using only polyethylene naphthalate. It can be seen that it is also excellent in fatigue.

Example 3

The radial tire manufactured by using the hybrid deep cord manufactured according to Example 1 of the present invention as a cap ply has a carcass layer having a radially outer fly turn up, and the carcass layer is installed to include one layer. At this time, the specifications of the carcass cord were as shown in Table 3 below, and were oriented at a 90 degree angle with respect to the circumferential intermediate surface of the tire. The fly turn-up 34 was to have a height of 40 to 80% with respect to the tire maximum cross-sectional height. The bead region 35 has a bead core 36 having a high strength steel wire having a diameter of 0.95 to 1.00 mm of 4 × 4 and a bead filler 37 having a Shore A hardness of 40 or more. The belt structure 38 is reinforced by a belt reinforcement layer having a capply 39 on one layer and an edge ply 44 on one layer on top, and the capply cord in the capply 39 is parallel to the circumferential direction of the tire. To be placed.

Example 4

A tire was manufactured in the same manner as in Example 3, except that a cord material for manufacturing a tire was used as the hybrid deep cord manufactured in Example 2.

Comparative Example 3

A tire was manufactured in the same manner as in Example 3, except that a cord material for manufacturing a tire was used as a deep cord manufactured according to Comparative Example 1.

[Comparative Example 4]

A tire was manufactured in the same manner as in Example 3, except that a cord material for manufacturing a tire was used as the deep cord manufactured in Comparative Example 2.

[Table 2]

Example 3 Example 4 Comparative Example 3 Comparative Example 4 Carcass Material Polyethylene terephthalate Polyethylene terephthalate Polyethylene terephthalate Polyethylene terephthalate Specification (d / ply twisted yarn) 1500d / 2 1500d / 2 1500d / 2 1500d / 2 Strong (Kg) 24 24 24 24 Modulus of elasticity (g / d) 50 50 50 50 Cap fly Material Hybrid Deep Code of Example 1 Hybrid Deep Code of Example 2 Deep Code of Comparative Example 1 Deep Code of Comparative Example 2 Specification (d / ply twisted yarn) 840D (2P) / 1000D (1P) 840D (1P) / 1000D (2P) 1000d / 2 840d / 2 Strong (Kg) 21.0 21.6 16.1 16.01 tire Flat ratio 0.60 0.60 0.60 0.60 Carcass floors One One One One Cap fly floor One One One One

The 205/65 R15 V tires manufactured according to Examples 3 and 4 and Comparative Examples 3 and 4 were mounted on a 2000cc class passenger car, and the noise generated in the vehicle was measured while driving at a speed of 60 km / h. The value is expressed in noise (dB), and the steering stability and ride comfort were evaluated by a skilled driver by driving a test course in units of 5 points out of 100 points, and the results are shown in Table 3 below. Durability is based on FMVSS 109's P-metric tire endurance test method, measuring 38 ° C (± 3 ° C) and 85, 90, 100% of the tire's nominal load. A total of 34 hours was used to determine the pass (OK) when no trace of bead separation, cord cutting, belt separation, etc. was found in any part of the tread, sidewall, carcass cord, inner liner, or bead. .

Table 3

division Example 3 Example 4 Comparative Example 3 Comparative Example 4 Tire weight (kg) 9.54 9.70 9.60 9.61 Ride 100 100 96 97 Steering stability 100 100 95 93 durability OK OK OK OK Uniformity 100 100 95 92 Noise (dB) 61.4 61.4 64.2 64.1

According to the test results of Table 3, the tire according to the present invention (Example 3-4) is noise reduction and control compared to Comparative Examples 3 or 4 using only polyethylene naphthalate yarn or polyhexamethyleneadipamide yarn in the cap ply. The effect was excellent in terms of stability, it can be seen that the uniformity of the tire is also improved.

 According to the present invention, a hybrid deep cord is prepared by using two polyhexamethyleneadipamide yarns and one polyethylenenaphthalate yarn or one polyhexamethyleneadipamide yarn and two polyethylenenaphthalate yarns. Polyethylenenaphthalate fibers can overcome the disadvantage of low adhesion with rubber, and polyhexamethyleneadipamide yarn can compensate for the relatively low elastic modulus, so that the treated cord formed from this yarn has high adhesion and strength. It is excellent and can be usefully used as a reinforcement for rubber products such as tires and belts or for other industrial uses.

According to the present invention, a hybrid deep cord made of polyethylene naphthalate and polyhexamethylene adiamide of the present invention is applied to a cap ply (belt reinforcement layer) of a pneumatic radial tire for a passenger car, thereby reducing noise and steering stability of a tire. Satisfactory results can be obtained.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims. .

Claims (4)

In the hybrid deep cord for radial tires, The hybrid deep cord is composed of three polyhexamethyleneadipamide yarns and one polyethylenenaphthalate yarn or one polyhexamethyleneadipamide yarn and three lower twisted yarns manufactured using two polyethylenenaphthalate yarns. Manufactured using raw cords added with staging The lower twist yarn is a hybrid deep cord for a radial tire, characterized in that each has been given a different number of twists. The hybrid deep cord for a radial tire according to claim 1, wherein the number of twists applied to said lower twist yarn is 440TPM of polyhexamethyleneadipamide and 470TPM of polyethylenenaphthalate. In radial pneumatic tires, A pair of parallel bead cores and at least one radial carcass ply wound around the bead core, a belt layer laminated on the outer circumference of the carcass, and a circumferential belt reinforcement layer formed on the outer circumference of the belt layer; , Radial pneumatic tire, characterized in that the belt reinforcing layer comprises the hybrid deep cord of claim 1. The method of claim 3, wherein Radial pneumatic tire, characterized in that the belt reinforcement layer is used as one layer.

Images