JPH11222775A - Cord for reinforcing rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cord for reinforcing a rubber having excellent adhesion to EPDM used as a material rubber such as a brake hose or a cooler hose and excellent in heat, hydrolytic and chemical resistances (durability in chemicals such as a brake fluid) in the rubber. SOLUTION: This rubber for reinforcing a rubber comprises a conjugated fiber containing a core component which is a polyester and a sheath component which is a polyamide in 30-90 wt.% ratio of the core component. The surface thereof is treated with a bonding treating liquid containing a resorcinol- formaldehyde precondensate, a vinylpyridine-styrene-butadiene copolymer latex, a polybutadiene latex and a chlorophenol-based compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber reinforcing cord useful as a reinforcing material for rubber products such as rubber hoses, tires and belts. In particular, ethylene / propylene / diene terpolymer rubbers (hereinafter, referred to as material rubbers for brake hoses and cooler hoses)
EPDM), and a rubber reinforcing cord having excellent heat resistance, hydrolysis resistance and chemical resistance in rubber.

[0002]

2. Description of the Related Art Polyester fibers have excellent mechanical strength and low elongation, so that rubber hoses, tires,
It has been widely used as a reinforcing material for rubber products such as belts.

[0003] Above all, rubber hoses reinforced with polyester fibers are used for brake hoses, cooler hoses and the like, taking advantage of their high modulus characteristics.

Fiber properties required as a reinforcing material for these hoses include not only physical properties such as high strength, high modulus and low shrinkage, but also adhesion to EPDM rubber as a rubber to be adhered. Good properties, heat resistance in rubber, excellent hydrolysis resistance and chemical resistance, and the like, but with conventional polyester fibers, hydrolysis resistance, heat resistance in rubber and It was difficult to eliminate changes over time in severe operating environment conditions such as brake fluid resistance, and it was difficult to obtain good adhesion to EPDM.

[0005] For this reason, in recent years, heat resistance in rubber,
For the purpose of improving hydrolysis resistance and chemical resistance, various studies have been made, for example, a method of reducing the amount of terminal carboxyl groups contained in the polyester fiber has been proposed, but even in this method, The effect of sufficiently suppressing the deterioration of the fibers in the rubber to a practical level could not be achieved.

In order to solve these problems, it is conceivable to apply a fiber having excellent heat resistance and chemical resistance such as polyphenylene sulfide or polymetaphenylene isophthalamide as a reinforcing material for a rubber hose.

However, although these heat-resistant fibers have excellent heat resistance, steam resistance and chemical resistance, the strength of the fibers is as low as 5 g / d at most, so that the pressure resistance of brake hoses and cooler hoses is high. In order to satisfy the requirement, the amount of the fiber is about twice as much as that of the polyester fiber, which causes a problem that the cost is greatly increased.

Further, since these heat-resistant fibers have a low initial tensile resistance (apparent Young's modulus), they cannot sufficiently satisfy the expansion amount required particularly for brake hoses and cooler hoses.

Further, these heat-resistant fibers have a problem that, even when an adhesive is applied thereto, good adhesiveness to rubber cannot be obtained due to the inherent property of being excellent in chemical resistance. For this reason, it has been considered difficult to develop it as a reinforcing material for brake hoses and cooler hoses at this time.

On the other hand, Japanese Patent Application Laid-Open No. 147327/1990 proposes that a composite fiber using polyester as a core component and polyamide as a sheath component is used as a rubber hose reinforcing cord. Although the effect of improving the heat resistance, steam resistance and chemical resistance is obtained, when this composite fiber is used to reinforce EPDM mainly used for brake hoses and cooler hoses, it is difficult to adhere to the rubber to be bonded. Good adhesion could not be obtained.

Further, Japanese Patent Application Laid-Open No. 2-147327 discloses that the above-mentioned composite fiber is twisted and twisted in the opposite directions by 40 T / 10 cm and 1500/500, respectively.
It is described that a dip cord is obtained by applying an adhesive and heat-treating the raw cord after forming the raw cord of No. 2, but the dip cord obtained by this method exhibits excellent characteristics for tires, When applied to applications, the hose has a large amount of expansion due to a low modulus, and has a high shrinkage, causing the cord to shrink due to the heat of vulcanization during hose manufacture, resulting in poor hose quality. A problem of being lost.

As described above, Japanese Patent Application Laid-Open No. 2-147327 discloses the use of a composite fiber using polyester as a core component and polyamide as a sheath component as a rubber hose reinforcing cord. Since no consideration is given to the properties required when used as a reinforcing material for hoses, such as adhesion to the adherend rubber, modulus and dry heat shrinkage, this composite fiber is used especially for coolers based on EPDM. It did not fully satisfy the properties required for reinforcing materials such as hoses and brake hoses.

[0013]

The present invention has been achieved as a result of studying the above-mentioned problems in the prior art.

That is, an object of the present invention is to have good adhesiveness to EPDM used as a material rubber, particularly for a brake hose or a cooler hose, and to further improve heat resistance, hydrolysis resistance and chemical resistance in rubber. An object of the present invention is to provide a rubber reinforcing cord having excellent properties (durability against chemicals such as brake fluid).

[0015]

In order to achieve the above object, the rubber reinforcing cord of the present invention has a core component of polyester, a sheath component of polyamide and a core component ratio of 30%.
A rubber reinforcing cord comprising a composite fiber of about 90% by weight, the surface of which contains a resorcinol-formaldehyde precondensate, a vinylpyridine-styrene-butadiene copolymer latex, a polybutadiene latex, and a chlorophenol compound. It is characterized by being treated with a liquid.

In particular, the solid content weight ratio of each component in the adhesive treatment liquid is such that vinyl pyridine-styrene-butadiene copolymer latex / polybutadiene latex = 1/3 to
3/1, resorcinol-formaldehyde precondensate /
(Total amount of vinyl pyridine-styrene-butadiene copolymer latex and polybutadiene latex) = 1 /
10 to 1/2, chlorophenolic compound / (total amount of resorcinol / formaldehyde precondensate, vinylpyridine-styrene-butadiene copolymer latex and polybutadiene latex) = 1/10 to 1/2, adhesion The solid content of the treatment liquid is 2.0
10.0 wt% (dry weight ratio), twist number 4
Twisted to 20T / 10cm, strength is more than 7g / d,
Elongation is 10% or more, elongation under load of 3 g / d is 6% or less, 1
The dry heat shrinkage at 50 ° C. is 6% or less,
Steam heat resistance represented by the ratio T1 / T0 of the cord strength T1 after treatment with steam for 8 hours to the cord strength T0 before treatment is 65% or more; and ethylene / propylene / diene triene It is preferably a reinforcing material for the original copolymer rubber hose, and more excellent effects can be obtained by applying these conditions.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS That is, in the rubber reinforcing cord of the present invention, the surface of the cord composed of the above-mentioned specific core-sheath type conjugate fiber is coated with a resorcinol / formaldehyde precondensate / rubber latex mixture (having a specific rubber composition). (RFL) is further treated with an adhesive treatment agent having a specific composition in which a chlorophenol compound is further blended, whereby the adhesion to EPDM is particularly improved, and the heat resistance, hydrolysis resistance and chemical resistance in rubber are further improved. It is improved and exhibits ideal performance especially when applied as a reinforcing cord for rubber hoses such as brake hoses and cooler hoses.

Hereinafter, the rubber reinforcing cord of the present invention will be described in detail.

The reinforcing cord for rubber hose of the present invention has a core-sheath type composite fiber using polyester as a core component and polyamide as a sheath component, and has a desired cord form.

This conjugate fiber has a high modulus close to that of polyester, and excellent heat resistance in rubber, heat and steam resistance, and chemical resistance. Specified birefringence, density and differential scanning calorimetry (DS
C) can be indicated by a parameter consisting of a combination of the peak melting temperature and the high initial tensile resistance and low terminal modulus of the polyester portion forming the core component.

Examples of the polyester which is the core component of the conjugate fiber include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, and copolymers thereof, among which polyethylene terephthalate is most preferably used. . Further, it is preferable that the intrinsic viscosity (η) of the polyester is 0.7 or more, more preferably 0.8 or more, and the degree of polymerization is high, since the strength of the conjugate fiber becomes 7.5 g / d or more.

Furthermore, in order to obtain a fiber having excellent heat resistance, it is important to spin a polyester polymer having a low carboxy terminal group concentration. For this reason, it is preferable to apply techniques such as adopting a low-temperature polymerization method during the production of the polyester polymer or adding a blocking agent in the polymerization step or the spinning step. At this time, examples of the blocking agent include oxazolines, epoxies, carbodiimides, ethylene carbonate, oxalates, and malonates.

The polyamide as the sheath component of the composite fiber includes nylon 6, nylon 66, nylon 610, and the like.
Nylon 612, Nylon 11, Nylon 12 and copolymers thereof are listed, among which Nylon 6 and Nylon 66 are most preferably used. Like the polyester core component, the polyamide sheath component preferably has a high degree of polymerization in order to obtain a high-strength conjugate fiber, and has a relative viscosity of sulfuric acid of 2.8 or more, more preferably 3.0 or more.

Further, it is preferable that a copper salt and other organic and inorganic compounds are added to the polyamide as a thermal oxidation deterioration preventing agent. In particular, copper salts such as copper iodide, copper acetate, copper chloride, and copper stearate are used as copper in an amount of 30 to 50.
0 ppm, alkali metal halides such as potassium iodide, sodium iodide and potassium bromide in an amount of 0.01 to 0.1 ppm.
Those containing 5% by weight and / or 0.01 to 0.1% by weight of an organic or inorganic phosphorus compound are preferred.

In the present invention, the intrinsic viscosity (IV) of the polyester was 8 g of a sample of orthochlorophenol 1
And the solution viscosity was measured at 25 ° C. using an Oswald viscometer, and the intrinsic viscosity (I
V) was determined. IV = 0.0242η + 0.2634 The relative viscosity of sulfuric acid (ηr) of the polyamide was measured by dissolving 1 g of a sample in 100 ml of 98% sulfuric acid and using an Oswald viscometer at 25 ° C.

In the present invention, it is important that the ratio of the above-mentioned core component to the composite fiber is 30 to 90% by weight. If the core component is less than 30% by weight, a composite fiber which can effectively utilize the modulus and dimensional stability of the polyester component cannot be obtained, and a rubber reinforcing cord satisfying the performance intended by the present invention is obtained. Can not. On the other hand, if the ratio of the core component exceeds 90% by weight, not only the heat resistance in the rubber and the heat resistance during vaporization deteriorate, but also, when used as a reinforcing material for a rubber hose, good adhesion to the rubber cannot be obtained. .

Further, it is preferable that both the core component and the sheath component are highly oriented and crystallized. In particular, the birefringence of the core component is preferably in the range of 160 × 10 ^{−3 to} 190 × 10 ^−3. preferable. When it is 160 × 10 ⁻³ or more, the strength of the conjugate fiber is 7.5 g / d or more, and the initial tensile resistance is 60 g / d or more.
When it is 0 ^-3 or less, it is particularly excellent in terms of dimensional stability and fatigue resistance.

On the other hand, if the birefringence of the sheath component is at least 50 × 10 ⁻³ , more preferably at least 55 × 10 ^−3, it is particularly preferable since a conjugate fiber having high strength and high initial tensile resistance can be obtained. .

In the present invention, the birefringence of each component is measured by the following method. That is, the sheath component is measured with a transmission interference microscope in the state of a composite fiber, and the core component is dissolved with a formic acid, sulfuric acid, fluorinated alcohol, or the like in a sheath component composed of a polyamide of the composite fiber, and then transmitted with a transmission interference microscope. Measure.

The density of the core component is 1.395 g / cm.
^When the density of the sheath component is ³ or more and the density of the sheath component is 1.140 g / cm ³ or more, the dimensional stability and fatigue resistance of the composite fiber are particularly improved, and the rubber reinforcing cord of the present invention is used as a reinforcing material for a rubber hose. In this case, it is preferable in that the heat resistance of the reinforcing material in rubber can be remarkably improved.

The density of the core component is measured by dissolving and removing the sheath component with formic acid, sulfuric acid, fluorinated alcohol or the like, and the density of the sheath component can be calculated from the density of the composite fiber and the density of the core component.

Further, the peak temperature of the melting curve of the differential scanning calorimetry (DSC) showing the crystal structure of the polyester as the core component is preferably 247 ° C. or higher,
In particular, the temperature is more preferably 248 ° C. or higher. In other words, the higher the peak temperature, the larger the crystal size and / or the higher the crystal perfection (crystallinity) and the more stable the fiber structure. When the peak temperature of the melting curve of the polyester core component fiber is 247 ° C. or higher, it is particularly excellent in terms of modulus, dimensional stability and fatigue resistance.

It is preferable that the core component composed of polyester has a high initial tensile resistance of 90 g / d or more and a low terminal modulus of 20 g / d or less. By having a high initial tensile resistance and a low terminal modulus, a decrease in strength in a rubber hose processing step is reduced, and fatigue resistance is improved. The initial tensile resistance was measured according to JIS L-1017 (1995).
The terminal modulus is the stress increase between the point on the SS curve obtained by subtracting 2.4% from the breaking elongation on the SS curve and the breaking point in the tensile test. Is divided by 2.4 × 10 ^-2 (g / d).

The composite fiber satisfying the above conditions is described in 7.
It has a high strength of 5 g / d or more, an initial tensile resistance of 60 g / d or more, and an elongation of 20% or less, which satisfies the preferable conditions of the conjugate fiber in the present invention. In particular, a conjugate fiber having a strength of 8 g / d or more, an initial tensile resistance of 70 g / d or more, and an elongation of 8 to 16% is preferable, and these can be achieved by appropriately combining the above conditions.

The conjugate fiber is manufactured by, for example, the following method.

That is, this is a method of melt-spinning each of the above-mentioned core component and sheath component polymers using two extruder type spinning machines. Specifically, polyester and polyamide polymers melted by the respective extruders are combined. The fiber is guided to a spinning pack, and is spun through a spinning nozzle as a composite fiber having polyester in the core and polyamide in the sheath.

At this time, the spinning speed is preferably 1500 m / min or more, more preferably 2000 m / min or more. Immediately below the spinneret, it is preferable to provide a heating atmosphere of 200 ° C. or more, preferably 260 ° C. or more over 10 cm or more and 1 m or less, and a heat retaining cylinder or a heating cylinder. After passing through the above-mentioned heated atmosphere, the spun yarn is rapidly solidified by cold air, and then, after being applied with an oil agent, is taken up by a take-off roll for controlling the spinning speed. It is important to control the heating atmosphere just below the spinneret in order to maintain spinnability during high-speed spinning.

The drawn undrawn yarn can be drawn continuously without winding. The birefringence of the undrawn yarn sampled on the take-off roll is a sheath component,
Both core components are 20 × 10 ⁻³ or more, and highly oriented ones can be obtained. In particular, the birefringence is preferably 30 × 10 ⁻³ or more.

The high-speed spinning employs a modulus of the composite fiber,
Although this has the effect of improving dimensional stability and fatigue resistance, it is surprising that this high-speed spinning significantly improves the durability of the core-sheath composite interface. The reason why this improvement effect is obtained is that unlike the conventional low-speed spinning method, in which a polyamide component that has undergone moisture absorption crystallization and an amorphous polyester component are combined, the high-speed spinning method uses a polyamide component and a polyester component. It is considered that the fact that the components are in a state where oriented crystallization proceeds and that the draw ratio after spinning is small contribute to the composite interface durability.

Next, the obtained undrawn yarn is subjected to thermal drawing in two or more stages, preferably in three or more stages. The temperature of the final stretching roller is at least 180 ° C., preferably at least 200 ° C., and the stretching ratio is in the range of 1.4 to 3.5 times.

The adoption of such high-temperature hot stretching also contributes to the improvement of composite interface durability. For example, when the third-stage stretching temperature is as low as less than 160 ° C., when the rubber hose using the rubber reinforcing cord of the present invention is repeatedly used at a high pressure, interfacial separation between the core component and the sheath component may occur. is there.

In the rubber reinforcing cord of the present invention, the above-mentioned conjugate fiber is formed into a desired cord form, and the surface of this cord is further treated with a resorcinol-formaldehyde precondensate, vinylpyridine-styrene-butadiene copolymer latex,
It has been treated with an adhesive treatment solution containing polybutadiene latex and a chlorophenol compound.

The resorcinol-formaldehyde precondensate in the adhesive treatment solution means a product obtained by reacting resorcinol and formaldehyde, and can usually be reacted in the presence of an alkali catalyst. The molar ratio of resorcinol (R) to formaldehyde (F) in the resorcinol-formaldehyde precondensate (RF) (F /
R) is preferably in the range of 1/1 to 3/1, preferably 1/1 to 2/1. If the molar ratio (F / R) of resorcinol (R) to formaldehyde (F) is less than 1/1, the resulting rubber reinforcing cord tends to have tackiness, and the processability at the time of knitting the hose tends to decrease, which is preferable. Absent. On the other hand, if the molar ratio exceeds 3/1, the adhesiveness to rubber is not preferred.

As the vinylpyridine-styrene-butadiene copolymer latex in the adhesive treatment solution, the copolymerization ratio of each component was as follows: 3-butadiene was 40 to 60% by weight;
10 to 20% by weight of 2-vinylpyridine, 3% of styrene
Those having 0 to 40% by weight are preferably used.

Specific examples of the chlorophenol-based compound used in the adhesive treatment liquid include 2-6 bis (2,4-dihydroxyphenylmethyl) -4-chlorophenol.

By mixing the initial condensate of the chlorophenol compound and resorcinol-formaldehyde, the adhesion between EPDM and synthetic fibers can be significantly improved.

The weight ratio of the solid content of the vinylpyridine-styrene-butadiene copolymer latex and the polybutadiene latex in the adhesive treatment liquid is preferably 1/3 to 3/1. If the solid content ratio is less than 1/3, EP
Adhesion to DM and tackiness in the completed reinforcing cord are generated, and the processability at the time of knitting the hose is reduced, which is not preferable. On the other hand, if the solid content weight ratio exceeds 3/1, it is not preferable in terms of adhesion to rubber.

The mixing ratio of the resorcinol-formaldehyde precondensate (RF) and the mixture of vinylpyridine-styrene-butadiene copolymer latex and polybutadiene latex (L) in the adhesive treatment liquid was 1/1 / solids weight ratio. It is preferably in the range of 10 to 1/2, particularly 1/8 to 1/3.

The resorcinol-formaldehyde precondensate (RF) and the mixture (L) have a solid content weight ratio of 1
If it is less than / 10, the adhesion to rubber tends to decrease, and the adhesiveness of the cord and the knitted fabric increases, which is not preferable. On the other hand, if the solid content weight ratio exceeds 1/2, the treated cord and knitted fabric become hard, which is not preferable.

In the adhesive treatment liquid of the present invention, the chlorophenol compound (C) and a mixture (RFL) of a resorcinol-formaldehyde precondensate, a vinylpyridine-styrene-butadiene copolymer latex and a polybutadiene latex are used. The solid content ratio (C / RFL) is 1
/ 10 to あ る. This C / RFL
When the solid content weight ratio is less than 1/10, it is not preferable in terms of adhesiveness to rubber. On the other hand, if it exceeds ２, the flexibility of the code tends to decrease, which is not preferable.

The adhesive treatment liquid comprising the above-mentioned components is used at a solid content of 10 to 20% by weight, and the solid content becomes 2.0 to 10.0% by weight on a dry weight basis with respect to the conjugate fiber. It is preferable that the treatment is performed as follows.

If the amount of the rubber reinforcing cord attached to the fiber is less than 2.0% by weight, it is not preferable in terms of adhesion to EPDM. If it exceeds 10.0% by weight, the flexibility of the cord tends to decrease, and the adhesiveness of the cord also increases, which is not preferable in terms of processability during cord production and hose production.

The rubber reinforcing cord of the present invention is obtained, for example, by dipping a cord made of the above-mentioned composite fiber in the above-mentioned adhesive treatment liquid,
After drying at a temperature of 70-150 ° C, 150-255 ° C
, Preferably at a temperature of 170 to 240 ° C.

If the drying after the application of the adhesive treatment liquid is performed at a temperature lower than 70 ° C., the above-mentioned RFL component may not be solidified and may adhere to the roller, thereby reducing the amount of adhesion to the cord, causing uneven adhesion and causing adhesion to rubber. May deteriorate.

When the heat treatment temperature is higher than 255 ° C., the RFL component of the bonding solution tends to deteriorate and the adhesiveness to rubber tends to decrease.
When the temperature is lower than 50 ° C., the adhesiveness to rubber may decrease.

In the present invention, in particular, the rubber reinforcing cord has a twist of 4 to 20 T / 10 cm, and has a strength of 7 g / d or more and an elongation of 10% or more and 3 g / d.
Elongation under load of 6% or less, dry heat shrinkage at 150 ° C of 6% or less, ratio T1 between cord strength T1 after treated with steam at 160 ° C for 8 hours and cord strength T0 before treatment.
It is preferable that the steaming heat resistance represented by / T0 has a characteristic of 65% or more.

When the number of twists is less than 4 T / 10 cm, the fibers tend to wear out when used as a reinforcing material for a hose, and the fatigue resistance tends to decrease.
If it exceeds / 10 cm, the modulus of the cord becomes small, and the amount of expansion of the hose tends to increase, which is not preferable.

If the strength is less than 7 g / g, it is not preferable because a large amount of fiber as a reinforcing material is required to satisfy the burst pressure of the hose.

If the elongation is less than 10%, the durability of the hose tends to decrease, which is not preferable.

If the elongation under load of 3 g / d exceeds 6%, the amount of expansion of the hose tends to increase, which is not preferable.

If the dry heat shrinkage exceeds 6%, the cord is shrunk by the heat of vulcanization during the production of the hose, and the hose quality tends to deteriorate, which is not preferable.

If the steaming heat resistance is less than 65%, the fibers are liable to be degraded due to hydrolysis during hose vulcanization or use of the hose, and the bursting pressure and durability of the hose tend to decrease, which is not preferred.

The rubber reinforcing cord of the present invention described above has good adhesiveness especially to EPDM, and furthermore has heat resistance, hydrolysis resistance and chemical resistance in rubber (durability against chemicals such as brake fluid). ), And the best effect is exhibited when using as a reinforcing material such as a brake hose or a cooler hose made of EPDM by utilizing such characteristics.

[0064]

EXAMPLES Hereinafter, the structure and effects of the present invention will be described more specifically with reference to examples. In addition, each measured value in the present invention means a value obtained by the following method. In addition, parts and% in Examples all show parts by weight and% by weight.

1. Cord strength (degree) and elongation After leaving the sample in a temperature control room at 20 ° C. and 65% RT for 24 hours or more, using a Tensilon tensile tester manufactured by Orientec Co., Ltd., a sample length of 25 cm and a take-up speed 30
An SS curve was determined at cm / min, and strength kg, elongation%, and strength per denier were determined, and strength g / d.

2. Dry heat shrinkage The dry heat shrinkage was measured according to the dry heat shrinkage measurement method A of JIS L-1017 (1995).

3. Steam resistance A treatment cord was put in an autoclave, heat-treated with steam at 160 ° C. for 8 hours, taken out, and the cord strength was measured by the above-mentioned method. Steam heat resistance retention (%) = (Cord strength after wet heat treatment /
3. Cord strength before wet heat treatment) x 100 Rubber heat resistance in rubber A rubber having the following composition is vulcanized to produce a rubber sheet having a thickness of 1.0 mm. Next, the processing cord was sandwiched between the rubber sheets, and then steamed at 150 ° C in an autoclave for 15 minutes.
Time processing. Next, the cord was taken out of the rubber, the cord strength before and after the treatment was measured, and the steam heat resistance in the rubber was determined by the following formula, and the steam heat resistance in the rubber was evaluated. Strength retention = (Strength of cord after steaming / Strength of cord before steaming) × 100 <Rubber formulation> (parts by weight) EPDM 100 Zinc white 5.0 Stearic acid 1.0 Carbon black 80.0 Processing oil 0 0.3 sulfur 1.5 2-mercaptobenzothiazole 0.5 tetramethylthiuram disulfide 1.05. Resin adhesion amount It was determined according to the dip pickup-mass method of JIS L-1017 (1995).

6. Test Cord Adhesive Force A test piece having a width of 25 mm was prepared using the compounded rubber and the treatment cord, and the treatment cord / rubber peeling force was measured according to the peel test method described in JISK 6328 (1995). That is, after unvulcanized rubber was attached to an aluminum pipe having a diameter of 10 cm and a length of 6 cm, a wrapping cloth (35 mm made by Toray) was wound, and after vulcanizing at 150 ° C. for 30 minutes using an autoclave, JIS K -6
The treated cord / rubber peeling force was measured according to the peeling test method described in 328.

7. Brake fluid resistance The treated cord is immersed in a bath of a commercial automotive brake fluid (Toyota 2500H) heated to 120 ° C for 504 hours, the strength before and after the treatment is measured, and the strength retention is calculated by the following formula. , And a measure of brake fluid resistance. Strength retention (%) = (Strength after immersion / Strength before immersion) x
100 Example 1 Intrinsic viscosity 1.05, carboxy terminal group concentration 8 eq / 10
⁶ g of polyethylene terephthalate (PET) and hexamethylene adipamide containing 0.02% of copper acetate and 0.1% of potassium iodide (nylon 66: sulfuric acid relative viscosity ηr
Each of 3.3) was melted by a 40φ extruder type spinning machine, led to a composite spinning pack, and a composite fiber having a core of polyethylene terephthalate and a sheath of polyamide was spun from a core-sheath composite spinneret.

At this time, the ratio of the core component and the sheath component is 50
/ 50. The die used had a hole diameter of 0.4 mmφ and 120 holes. As for the polymer temperature, polyethylene terephthalate was melted at 295 ° C and polyamide was melted at 290 ° C.

A heating cylinder of 15 cm was attached immediately below the base, and the atmosphere was heated to 290 ° C. in the cylinder.
The atmosphere temperature is an atmosphere temperature measured at a position 10 cm below the die surface and 1 cm away from the outermost yarn. An annular chimney having a length of 400 mm was attached to the bottom of the heating tube, and cooled air was blown from the periphery of the yarn at 25 ° C. at 40 m / min.

Next, after the oil agent was applied, the yarn speed was controlled by a take-off roll, and the film was continuously drawn without winding. The film was stretched by five steps of Nelson-type rolls, stretched in three stages, then relaxed by 3% heat treatment and wound up.

The stretching conditions are as follows: the take-up roll temperature is 60 ° C.
The first stretching roll temperature is 120 ° C., the second stretching roll temperature is 190 ° C., the third stretching roll temperature is 225 ° C., the tension adjusting roll after stretching is not heated, and the one-stage stretching ratio is 70% of the total stretching ratio. It was distributed and stretched in two stages. Spinning speed,
The yarn was drawn while changing the total draw ratio, but the discharge amount was changed in accordance with the spinning temperature and the draw ratio so that the fineness of the drawn yarn was about 500 denier. The obtained drawn yarn was combined into three yarns to give 1500 denier.

Further, the 1500 obtained in this way is
The denier core-sheath composite fiber was twisted at a twist number of 4T / 10 cm to obtain a raw cord.

On the other hand, in the presence of an alkali catalyst, resorcinol (R) and formalin (F) are reacted at a molar ratio (F / R). 3 /
2 and aged for 2 hours.
% Of the initial condensate is added to 100 parts of a mixed latex obtained by mixing a vinylpyridine-styrene-butadiene copolymer latex (VP latex) and a polybutadiene latex (BR latex) at a solid content weight ratio of 50/50. By mixing and aging for 24 hours, an RFL having a solid content of 30% was prepared (RF / L = 1 /
8).

Next, 25% of Casabond E (manufactured by Thomas Swan) was added as a chlorophenol-based compound.
The adhesive treatment liquid was prepared by adding and diluting with water to a solid content concentration of 20%.

Next, the raw cord was immersed in the above-mentioned adhesive treatment solution using a computer treater (manufactured by Ritzler), dried at 150 ° C. for 120 seconds, and subsequently dried at 240 ° C.
After heat treatment at 60 ° C. for 60 seconds, the obtained treatment cord was wound up with a winder.

Various characteristics of this processed code were measured and evaluated, and the results are shown in Table 1.

Examples 2 to 6 The core / sheath ratio of the core-sheath composite fiber and the composition of the adhesive treatment liquid were as follows:
The same operation as in Example 1 was performed except for the change as shown in Table 1, and the results of evaluation of the obtained processing codes are also shown in Table 1. Denapon, Denabond A and Denabond B are chlorophenol compounds manufactured by Nagase Kasei.

Comparative Examples 1 to 6 The core / sheath ratio of the core-sheath composite fiber and the composition of the adhesive treatment liquid were as follows:
The same operation as in Example 1 was performed except for the change as shown in Table 2, and the results of evaluation of the obtained processing codes are shown in Table 2. In the table, SBR means a styrene-butadiene copolymer latex.

Comparative Example 7 Polyethylene terephthalate was melt spun, drawn, drawn, and stretched to obtain a 1500 denier multifilament (intrinsic viscosity: 0.95) by twisting a 4T / 10 cm twisted number to obtain a raw cord. Was.

The same operation as in Example 1 was performed except that the raw polyester fiber cord obtained by the above method was used, and the results of evaluation of the obtained treated cords are also shown in Table 2.

[0083]

[Table 1]

[Table 2] As is clear from the results of Tables 1 and 2, the rubber reinforcing cord (Examples 1 to 6) of the present invention has the same modulus and dimensional stability as the conventional polyester fiber cord (Comparative Example 7). Further, as compared with the conventional polyester fiber cord, steam resistance, steam resistance in rubber and adhesiveness are remarkably improved.

On the other hand, the rubber reinforcing cords (Comparative Examples 1 to 7) treated with an adhesive treatment liquid lacking the conditions specified in the present invention are:
It does not satisfy at least one of adhesiveness to rubber, heat resistance in rubber, hydrolysis resistance and brake fluid resistance.

[0085]

As described above, the rubber reinforcing cord of the present invention has a rubber reinforced fiber comprising a composite fiber having a core component of polyester, a sheath component of polyamide and a core component ratio of 30 to 90% by weight. A resorcinol-formaldehyde precondensate, vinylpyridine-
Since it has been treated with an adhesive treatment solution containing a styrene-butadiene copolymer latex, a polybutadiene latex and a chlorophenol-based compound, it has particularly good adhesion to EPDM, and has heat resistance and resistance in rubber. Has excellent hydrolysis and chemical resistance (durability against chemicals such as brake fluid), and is a cord for reinforcing rubber hoses, tires and belts, and other rubber products, especially EPDM brake hoses and cooler hose cords. Useful as

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI D06M 15/233 D06M 15/233 15/693 15/693 F16L 11/08 F16L 11/08 A // C08J 5/06 CEQ C08J 5 / 06 CEQ D01F 8/14 D01F 8/14 C

Claims (5)

[Claims] 1. A rubber reinforcing cord comprising a composite fiber having a core component of polyester, a sheath component of polyamide and a core component ratio of 30 to 90% by weight, the surface of which is a resorcinol-formaldehyde precondensate; A rubber reinforcing cord which has been treated with an adhesive treatment liquid containing a vinylpyridine-styrene-butadiene copolymer latex, a polybutadiene latex and a chlorophenol compound. 2. The weight ratio of solid components of each component in the adhesive treatment liquid is as follows: vinylpyridine-styrene-butadiene copolymer latex / polybutadiene latex = 1/3 to 3/1, resorcinol / formaldehyde precondensate / (vinyl Total amount of pyridine-styrene-butadiene copolymer latex and polybutadiene latex) = 1/10 to 1 /
2. Chlorophenolic compound / (total amount of resorcinol-formaldehyde precondensate, vinylpyridine-styrene-butadiene copolymer latex and polybutadiene latex) = 1/10 to 1/2. The rubber reinforcing cord according to claim 1. 3. The rubber reinforcement according to claim 1, wherein the solid content of the adhesive treatment liquid is 2.0 to 10.0% by weight (dry weight ratio) with respect to the conjugate fiber. Code. 4. A single twist of 4 to 20 T / 10 cm in twist number, strength of 7 g / d or more, and elongation of 10% or more, 3 g / d.
Elongation under load of 6% or less, dry heat shrinkage at 150 ° C of 6% or less, ratio of cord strength T1 after treatment with steam at 160 ° C for 8 hours to cord strength T0 before treatment. The rubber reinforcing cord according to any one of claims 1 to 3, wherein the steam heat resistance represented by T1 / T0 is 65% or more. 5. The rubber reinforcing cord according to claim 1, which is a reinforcing material for an ethylene / propylene / diene terpolymer rubber hose.