CA1336740C - Composite material - Google Patents
Composite materialInfo
- Publication number
- CA1336740C CA1336740C CA000606310A CA606310A CA1336740C CA 1336740 C CA1336740 C CA 1336740C CA 000606310 A CA000606310 A CA 000606310A CA 606310 A CA606310 A CA 606310A CA 1336740 C CA1336740 C CA 1336740C
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- CA
- Canada
- Prior art keywords
- rubber
- weight
- composite material
- parts
- adhesion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
- C08J5/10—Reinforcing macromolecular compounds with loose or coherent fibrous material characterised by the additives used in the polymer mixture
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/06—Sulfur
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
- C08K5/098—Metal salts of carboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
- C08K5/45—Heterocyclic compounds having sulfur in the ring
- C08K5/46—Heterocyclic compounds having sulfur in the ring with oxygen or nitrogen in the ring
- C08K5/47—Thiazoles
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2321/00—Characterised by the use of unspecified rubbers
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Tires In General (AREA)
Abstract
A composite material comprising a rubber composition and a metal material, wherein the rubber composition contains, per 100 parts by weight of rubber, 0 to 0.5 part by weight of a cobalt salt of an organic acid, 3 to 6 parts by weight of sulfur, and N-oxy-diethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2-benzothiazolylsulfenamide as a vulcanization accelerator, and the metal material is provided with a plating of a ternary alloy consisting of copper, zinc, and nicke.
Description
FIELD OF THE INVENTION
The present invention relates to a composite material comprising a rubber material (or composition) and a metal material. More particularly, the present invention relates to a composite material that is adapted for use in industrial rubber articles such as tires for vehicles and conveyor belts and which retains good adhesion between metal and rubber even after the latter's aging.
BACKGROUND OF THE INVENTION
The performance required of tires for vehicles, conveyor belts and other industrial rubber articles has become increasingly versatile. In the tires for vehicles, radial tires are extensively used not only as tires for passenger cars but also as tires for large cars such as trucks and buses, and the useful life of tires has been remarkably extended by several reasons including the advances in the mixing technology of tread rubber. Large tires that have been used for large cars such as trucks and buses are retreaded after the end of their primary life so that they are put to service for the secondary, and even tertiary, use. These uses sometimes extend to several hundreds thousand kilometers and the belts and carcasses of tires on vehicles are required to perform satisfactorily for this period.
1 In the above radial tires, rubber-coated steel cords are used to form the belts or carcasses in order to improve the steering stability, structural durability, wear resistance and puncture resistance of the tires.
With such the tires, the adhesion between rubber material and metal material can be a problem.
Rubber material normally adheres to metal material when sulfur mixed in the rubber material during vulcanization reacts with copper in the plating on the metal material so as to form a sulfide at the rubber-metal interface. When a tire is rolling on the road, the hysteresis loss of the rubber material generates heat and if the generated heat is large enough to break the adhesion between the rubber material and the metal material, the coated rubber will separate from the steel cord and this "separation" renders further rolling of the tire on the road impossible.
Further, the tire tread or sidewall may sometimes be damaged when the tire is rolling on the road. If the damage is deep enough to reach the steel cord, moisture that has permeated the tire through the damaged part will be vaporized by the heat generated during tire rolling on the road and the vapor getting into the space between filaments in the steel cord will destroy the adhesion between the steel cord and the coated rubber, thereby inducing n separation" .
1 A further problem will occur if the tire is inflated with moisture containing air. The moisture will penetrate through innerliner of the tire to reach the steel cord and this may induce "separation" by breaking the adhesion between the coated rubber and the steel cord.
With a view to avoiding these phenomena, various techniques have been proposed that are chiefly intended to improve the adhesion between the rubber and the steel cords. One of the techniques proposed concerns the compounding techniques of rubber material with which steel cords are coated. It was discovered as early as in the nineteen-fifties that the adhesion between the rubber and the steel cords could be improved by incorporating cobalt salts of organic acids in the rubber material, and many studies have been conducted regarding the quantity and type of such the cobalt salts to be added. For example, JP-A-60-42440 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application") shows that improved adhesion can be attained by optimizing the quantities of sulfur and cobalt salts of organic acids.
Another approach has been to use the HRH based composition mixing white carbon, resorcin and hexamethylenetetramine.
However, if the cobalt salts of organic acids are added in large amounts, the unvulcanized rubber will be deteriorated or the deterioration of adhesive power 1 due to thermal aging will occur either on account of hot or prolonged vulcanization or rolling of the tire on the road for a distance of many hundred kilometers. On the other hand, the HRH based compositions cause problems during production such as environmental pollution and rubber scorching.
The second approach that has been taken to improve the adhesion between the rubber and the steel cords is directed at the plating layer to be deposited on a metal material. JP-B-51-8389 (the term "JP-B" as used herein refers to an "examined Japanese patent publication") and JP-A-55-105548 disclose a plating layer containing nickel. Alloy platings containing three or four metals are disclosed in JP-A-55-45884, JP-A-55-71887, JP-A-55-105548, JP-A-56-826045, JP-A-54-89940, JP-A-61-243194, JP-A-61-72545, etc.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a composite material comprising a rubber composi-tion (material) and a metal material that is successfullyimproved over the prior art not only in adhesion after thermal aging but also in adhesion after wet heat aging (hereinafter referred to as "heat resistance" and "wet heat resistance", respectively) without causing other problems, in particular, those which have conventionally - 1 33674(~
1 been encountered during production. This object of the present invention is attained by combining a metal material having an improved plating layer and a rubber material having a compound formulation suitable for this metal material. More specifically, the present invention provides a composite material comprising a rubber composi-tion and a metal material, wherein the rubber composition contains, per 100 parts by weight of rubber, O to 0.5 part by weight of a cobalt salt of an organic acid, 3 to 6 parts by weight of sulfur, and N-oxydiethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2-benzothiazolyl-sulfenamide as a vulcanization accelerator, and the metal material is provided with a plating of a ternary alloy consisting of copper, zinc, and nickel.
DETAILED DESCRIPTION OF THE INVENTION
Examples of the cobalt salts of organic acids that can be used in the present invention include cobalt naphthenate, cobalt oleate, cobalt maleate and cobalt stearate. In order to ensure high initial strength of adhesion, these cobalt salts of organic acids preferably contain cobalt in an amount of 8 to 10 wt%.
The shape of the metal material can be freely chosen in accordance with the type of industrial article to which the composite material of the present invention is applied. If it is applied to conveyor belts or tires 1 for vehicles, the metal material is preferably used in the form of cords, particularly in the form of steel cords.
It has generally been held that high initial strength of adhesion is not attainable unless cobalt salts of organic acids are used in amounts exceeding 0.5 part by weight per 100 parts by weight of rubber.
However, in accordance with the present invention, N-oxydiethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2-benzothiazolylsulfenamide is added to rubber as a vulcanization accelerator and the resulting rubber composition is combined with a metal material provided with a plating.of a ternary alloy consisting of copper, zinc or nickel, and this ensures satisfactory strength of adhesion even if a cobalt salt of an organic acid is present in an amountof not m~re than 0.5 part by weight, and particularly the satisfactory strength of adhesion is ensured even in an extreme case where such the cobalt salts of organic acids are entirely absent. Therefore, the present invention is capable of avoiding the problems during production and aging after vulcanization which have occurred in the prior art on account of the incorporation of cobalt salts of organic acids in large amounts.
1 If the rubber composition of the present inven-tion contains less than 3 parts by weight of sulfur, satisfactory initial strength of adhesion is not attain-able. If the sulfur content exceeds 6 parts by weight, the heat resistance of the resulting composite material will be impaired. Accordingly, the amount of sulfur used in the rubber composition of the present invention is generally 3 to 6 parts by weight and preferably 3.5 to 5.5 parts by weight,per 100 parts by weight of rubber.
The vulcanization accelerator is preferably used in the present invention in an amount of from 0.5 to 2 parts by weight and more preferably from 0.5 to 1.5 parts by weight,per 100 parts by weight of rubber. If the vulcanization accelerator is incorporated in an amount of less than 0.5 part by weight, the speed of vulcanization tends to be slow and poor adhesion often results. If the content of the vulcanization accelerator exceeds 2 parts by weight, the modulus of the rubber becomes so high as to occasionally cause adverse effects on the adhesion between the rubber material and the metal material or the breaking strength of the rubber itself.
The metal material of the composite material of the present invention must be plated with a ternary alloy consisting of copper, zinc and nickel. An advantageous ` 1 336740 1 composition of this plating alloy consists of 60 to 75 wt%
copper, 4 to 10 wt% nickel and the balance being zinc. If the copper content is less than 60 wt%, desired initial strength of adhesion is not attainable. If copper is present in an amount exceeding 75 wt%, the contents of nickel and zinc are too much reduced to ensure satisfac-tory heat and wet heat resistance. Nickel need not be present in a large amount and a required minimum amount is preferably 4 wt%. If the nickel content exceeds 10 wt%, the reaction of adhesion is inhibited and the necessary initial strength of adhesion is difficult to obtain.
The following example is provided for the purpose of further illustrating the present invention but the present invention is not to be construed as being limited thereto.
EXAMPLE
Rubber compositions having the basic mixing preparation (recipe) shown in Table 1 were prepared by varying the amounts of sulfur and cobalt stearate as well as the type and amount of vulcanization accelerator, as shown in Table 2.
Ingredients Parts by weight Natural rubber 100 HAF (High Abrasion Furnance) 50 Zinc white (ZnO) 8 Antiaging agent* 2 Cobalt stearate** Variable (see Table 2) Sulfur Variable (see Table 2) Vulcanization accelerator Variable (see Table 2) * 2,2,4-Trimethyl-1,2-dihydroquinoline polymer ** Cobalt content = 9 wt%
In Table 2, Rubber Composition Nos. 1 to 18 were those prepared in accordance with the present invention.
Rubber Composition (mixing ratio) Sample Cobalt StearateSulfur Vulcanization Accelerator No. Amount Amount ~ Amount (pts. by wt.)(pts. by wt.) (pts. by wt.) l 0 3.5 A 1.0 2 0 4.5 n 1.0 3 5 5 1.0 4 0.5 3.5 " 1.0 0.5 4.5 " 1.0 6 0.5 5.5 1.0 7 0 3.5 B 1.0 8 0 4.5 n 1.0 9 0 5.5 " 1.0 0.5 3.5 " 1.0 11 0.5 4.5 1.0 12 0.5 5.5 " 1.0 13 0 4.5 A 0.5 14 0 4.5 n 2.0 0 4.5 2.5 16 0 4.5 B 0.5 17 0 4.5 n 2.0 18 0 4.5 " 2.5 19 1.0 3.0 C 1.0 1.0 3.5 " 1.0 21 1.0 5.0 " 1.0 (cont'd) Rubber Composition (mix_ng ratio) Sample Cobalt StearateSulfur Vu_canization Accelerator No. Amount Amount ~ Amount (pts. by wt.)(pts. by wt.) (pts. by wt.) 22 1.0 5.5 C 1.0 23 1.0 6.5 " 1.0 24 1.0 7.0 " 1.0 1.5 2.5 " 1.0 26 1.5 4.5 " 1.0 27 1.5 6.5 " 1.0 28 2.0 3.5 " 1.0 29 2.0 4.0 " 1.0 2.0 5.5 " 1.0 31 2.0 6.0 " 1.0 32 2.5 2.5 " 1.0 33 2.5 4.5 " 1.0 34 3.0 3.0 " 1.0 3.0 5.0 " 1.0 36 3.0 7.0 " 1.0 37 4.0 4.0 " 1.0 38 4.0 6.0 " 1.0 39 5'0 3.0 " 1.0 s,o 5~0 " 1.0 41 5.0 7.0 " 1.0 42 0 4.0 " 1.0 43 0 5.5 " 1.0 (cont'd) Rubber Composition (mixing ratio) Sample Cobalt StearateSulfur Vulcanization Accelerator No. Amount Amount ~YE~ Amount (pts. by wt.)(pts. by wt.) (pts. by wt.) 44 0 6.0 C 1.0 0 7,0 ~ 1.0 46 0.5 2.5 " 1.0 47 0.5 6.5 " 1.0 48 2.0 8.0 " 1.0 49 4.0 9.0 " 1.0 6.0 6.0 " 1.0 51 7.0 4.0 " 1.0 52 7.0 10.0 n 1.0 * A: N-Oxydiethylene-2-benzothiazolylsulfenamide (Invention) B: N-tert-Butyl-2-benzothiazolylsulfenamide (Invention) C: N,N-Dicyclohexyl-2-benzothiazolylsulfenamide (Comparison) Subsequently, steel cords (1 x 5/0.25) were plated with alloys having the compositions shown in Table 3.
Composition of Plating Steel Cord Alloy (wt%) Sample No. Copper Zinc Nickel Remarks A 65 35 0 Comparison B 65 33 2 Invention C 65 31 4 "
D 65 29 6 "
E 65 27 8 "
F 65 25 10 "
H 65 5 35 "
The rubber compositions shown in Table 2 were combined in various ways with the steel cords shown in Table 3 and the resulting mixing compositions were vulcanized under predetermined conditions, followed by aging under the conditions shown in Table 4. Thereafter, the rubber material was peeled apart mechanically from the cords and the peel force, i.e., the force required to cause separation between the rubber and the cord, was measured. At the same time, the state of rubber adhered to the surface of cords was visually evaluated on a 10-point scoring basis. The results are shown in Table 5, as well as in Table 6. The greater the values shown in these tables, the better are the results.
Aging Condition Aging Relative ConditionTime Temperature Humidity (hr) (C) (%) (a) 0 -- __ (b) 400 80 95 (c) 24 120 100 (d) 96 120 --Condition (a) was used for measuring the initial strength of adhesion; conditions (b) and (c) were used for measuring wet heat resistance; and condition (d) was used for measuring heat resistance.
Among the combinations shown in Table 5 and Table 6, those consisting of Rubber Composition Samples 1 to 18 and Steel Cord Samples B to H provided composite materials within the scope of the present invention.
Table 5 shows the results of visual evaluation of rubber adhesion on a 10-point scoring basis and the greater the values shown in these tables, the better are the results.
Table 6 shows the results of measurements of peeling force.
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m ~ a ~ ~ ~ s 1 The composite materials prepared in accordance with the present invention exhibited satisfactory results under all of the conditions employed. Rubber Composition Nos. 1 to 3, 7 to 9, and 13 to 18 enabled the preparation of composite materials that ensured satisfactory adhesion without employing any cobalt salt of organic acids. This advantage was especially noticeable when the rubber compositions specified above were combined with Steel Cord Samples C to F.
The composite material of the present invention ensures improved adhesion between a rub,ber material and a metal material throughout the period of its use including from the initia~ stage to after aging by heat or wet heat. In addition, this composite material solved all of the problems conventionally encountered during production such as environmental pollution and rubber scorching.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
The present invention relates to a composite material comprising a rubber material (or composition) and a metal material. More particularly, the present invention relates to a composite material that is adapted for use in industrial rubber articles such as tires for vehicles and conveyor belts and which retains good adhesion between metal and rubber even after the latter's aging.
BACKGROUND OF THE INVENTION
The performance required of tires for vehicles, conveyor belts and other industrial rubber articles has become increasingly versatile. In the tires for vehicles, radial tires are extensively used not only as tires for passenger cars but also as tires for large cars such as trucks and buses, and the useful life of tires has been remarkably extended by several reasons including the advances in the mixing technology of tread rubber. Large tires that have been used for large cars such as trucks and buses are retreaded after the end of their primary life so that they are put to service for the secondary, and even tertiary, use. These uses sometimes extend to several hundreds thousand kilometers and the belts and carcasses of tires on vehicles are required to perform satisfactorily for this period.
1 In the above radial tires, rubber-coated steel cords are used to form the belts or carcasses in order to improve the steering stability, structural durability, wear resistance and puncture resistance of the tires.
With such the tires, the adhesion between rubber material and metal material can be a problem.
Rubber material normally adheres to metal material when sulfur mixed in the rubber material during vulcanization reacts with copper in the plating on the metal material so as to form a sulfide at the rubber-metal interface. When a tire is rolling on the road, the hysteresis loss of the rubber material generates heat and if the generated heat is large enough to break the adhesion between the rubber material and the metal material, the coated rubber will separate from the steel cord and this "separation" renders further rolling of the tire on the road impossible.
Further, the tire tread or sidewall may sometimes be damaged when the tire is rolling on the road. If the damage is deep enough to reach the steel cord, moisture that has permeated the tire through the damaged part will be vaporized by the heat generated during tire rolling on the road and the vapor getting into the space between filaments in the steel cord will destroy the adhesion between the steel cord and the coated rubber, thereby inducing n separation" .
1 A further problem will occur if the tire is inflated with moisture containing air. The moisture will penetrate through innerliner of the tire to reach the steel cord and this may induce "separation" by breaking the adhesion between the coated rubber and the steel cord.
With a view to avoiding these phenomena, various techniques have been proposed that are chiefly intended to improve the adhesion between the rubber and the steel cords. One of the techniques proposed concerns the compounding techniques of rubber material with which steel cords are coated. It was discovered as early as in the nineteen-fifties that the adhesion between the rubber and the steel cords could be improved by incorporating cobalt salts of organic acids in the rubber material, and many studies have been conducted regarding the quantity and type of such the cobalt salts to be added. For example, JP-A-60-42440 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application") shows that improved adhesion can be attained by optimizing the quantities of sulfur and cobalt salts of organic acids.
Another approach has been to use the HRH based composition mixing white carbon, resorcin and hexamethylenetetramine.
However, if the cobalt salts of organic acids are added in large amounts, the unvulcanized rubber will be deteriorated or the deterioration of adhesive power 1 due to thermal aging will occur either on account of hot or prolonged vulcanization or rolling of the tire on the road for a distance of many hundred kilometers. On the other hand, the HRH based compositions cause problems during production such as environmental pollution and rubber scorching.
The second approach that has been taken to improve the adhesion between the rubber and the steel cords is directed at the plating layer to be deposited on a metal material. JP-B-51-8389 (the term "JP-B" as used herein refers to an "examined Japanese patent publication") and JP-A-55-105548 disclose a plating layer containing nickel. Alloy platings containing three or four metals are disclosed in JP-A-55-45884, JP-A-55-71887, JP-A-55-105548, JP-A-56-826045, JP-A-54-89940, JP-A-61-243194, JP-A-61-72545, etc.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a composite material comprising a rubber composi-tion (material) and a metal material that is successfullyimproved over the prior art not only in adhesion after thermal aging but also in adhesion after wet heat aging (hereinafter referred to as "heat resistance" and "wet heat resistance", respectively) without causing other problems, in particular, those which have conventionally - 1 33674(~
1 been encountered during production. This object of the present invention is attained by combining a metal material having an improved plating layer and a rubber material having a compound formulation suitable for this metal material. More specifically, the present invention provides a composite material comprising a rubber composi-tion and a metal material, wherein the rubber composition contains, per 100 parts by weight of rubber, O to 0.5 part by weight of a cobalt salt of an organic acid, 3 to 6 parts by weight of sulfur, and N-oxydiethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2-benzothiazolyl-sulfenamide as a vulcanization accelerator, and the metal material is provided with a plating of a ternary alloy consisting of copper, zinc, and nickel.
DETAILED DESCRIPTION OF THE INVENTION
Examples of the cobalt salts of organic acids that can be used in the present invention include cobalt naphthenate, cobalt oleate, cobalt maleate and cobalt stearate. In order to ensure high initial strength of adhesion, these cobalt salts of organic acids preferably contain cobalt in an amount of 8 to 10 wt%.
The shape of the metal material can be freely chosen in accordance with the type of industrial article to which the composite material of the present invention is applied. If it is applied to conveyor belts or tires 1 for vehicles, the metal material is preferably used in the form of cords, particularly in the form of steel cords.
It has generally been held that high initial strength of adhesion is not attainable unless cobalt salts of organic acids are used in amounts exceeding 0.5 part by weight per 100 parts by weight of rubber.
However, in accordance with the present invention, N-oxydiethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2-benzothiazolylsulfenamide is added to rubber as a vulcanization accelerator and the resulting rubber composition is combined with a metal material provided with a plating.of a ternary alloy consisting of copper, zinc or nickel, and this ensures satisfactory strength of adhesion even if a cobalt salt of an organic acid is present in an amountof not m~re than 0.5 part by weight, and particularly the satisfactory strength of adhesion is ensured even in an extreme case where such the cobalt salts of organic acids are entirely absent. Therefore, the present invention is capable of avoiding the problems during production and aging after vulcanization which have occurred in the prior art on account of the incorporation of cobalt salts of organic acids in large amounts.
1 If the rubber composition of the present inven-tion contains less than 3 parts by weight of sulfur, satisfactory initial strength of adhesion is not attain-able. If the sulfur content exceeds 6 parts by weight, the heat resistance of the resulting composite material will be impaired. Accordingly, the amount of sulfur used in the rubber composition of the present invention is generally 3 to 6 parts by weight and preferably 3.5 to 5.5 parts by weight,per 100 parts by weight of rubber.
The vulcanization accelerator is preferably used in the present invention in an amount of from 0.5 to 2 parts by weight and more preferably from 0.5 to 1.5 parts by weight,per 100 parts by weight of rubber. If the vulcanization accelerator is incorporated in an amount of less than 0.5 part by weight, the speed of vulcanization tends to be slow and poor adhesion often results. If the content of the vulcanization accelerator exceeds 2 parts by weight, the modulus of the rubber becomes so high as to occasionally cause adverse effects on the adhesion between the rubber material and the metal material or the breaking strength of the rubber itself.
The metal material of the composite material of the present invention must be plated with a ternary alloy consisting of copper, zinc and nickel. An advantageous ` 1 336740 1 composition of this plating alloy consists of 60 to 75 wt%
copper, 4 to 10 wt% nickel and the balance being zinc. If the copper content is less than 60 wt%, desired initial strength of adhesion is not attainable. If copper is present in an amount exceeding 75 wt%, the contents of nickel and zinc are too much reduced to ensure satisfac-tory heat and wet heat resistance. Nickel need not be present in a large amount and a required minimum amount is preferably 4 wt%. If the nickel content exceeds 10 wt%, the reaction of adhesion is inhibited and the necessary initial strength of adhesion is difficult to obtain.
The following example is provided for the purpose of further illustrating the present invention but the present invention is not to be construed as being limited thereto.
EXAMPLE
Rubber compositions having the basic mixing preparation (recipe) shown in Table 1 were prepared by varying the amounts of sulfur and cobalt stearate as well as the type and amount of vulcanization accelerator, as shown in Table 2.
Ingredients Parts by weight Natural rubber 100 HAF (High Abrasion Furnance) 50 Zinc white (ZnO) 8 Antiaging agent* 2 Cobalt stearate** Variable (see Table 2) Sulfur Variable (see Table 2) Vulcanization accelerator Variable (see Table 2) * 2,2,4-Trimethyl-1,2-dihydroquinoline polymer ** Cobalt content = 9 wt%
In Table 2, Rubber Composition Nos. 1 to 18 were those prepared in accordance with the present invention.
Rubber Composition (mixing ratio) Sample Cobalt StearateSulfur Vulcanization Accelerator No. Amount Amount ~ Amount (pts. by wt.)(pts. by wt.) (pts. by wt.) l 0 3.5 A 1.0 2 0 4.5 n 1.0 3 5 5 1.0 4 0.5 3.5 " 1.0 0.5 4.5 " 1.0 6 0.5 5.5 1.0 7 0 3.5 B 1.0 8 0 4.5 n 1.0 9 0 5.5 " 1.0 0.5 3.5 " 1.0 11 0.5 4.5 1.0 12 0.5 5.5 " 1.0 13 0 4.5 A 0.5 14 0 4.5 n 2.0 0 4.5 2.5 16 0 4.5 B 0.5 17 0 4.5 n 2.0 18 0 4.5 " 2.5 19 1.0 3.0 C 1.0 1.0 3.5 " 1.0 21 1.0 5.0 " 1.0 (cont'd) Rubber Composition (mix_ng ratio) Sample Cobalt StearateSulfur Vu_canization Accelerator No. Amount Amount ~ Amount (pts. by wt.)(pts. by wt.) (pts. by wt.) 22 1.0 5.5 C 1.0 23 1.0 6.5 " 1.0 24 1.0 7.0 " 1.0 1.5 2.5 " 1.0 26 1.5 4.5 " 1.0 27 1.5 6.5 " 1.0 28 2.0 3.5 " 1.0 29 2.0 4.0 " 1.0 2.0 5.5 " 1.0 31 2.0 6.0 " 1.0 32 2.5 2.5 " 1.0 33 2.5 4.5 " 1.0 34 3.0 3.0 " 1.0 3.0 5.0 " 1.0 36 3.0 7.0 " 1.0 37 4.0 4.0 " 1.0 38 4.0 6.0 " 1.0 39 5'0 3.0 " 1.0 s,o 5~0 " 1.0 41 5.0 7.0 " 1.0 42 0 4.0 " 1.0 43 0 5.5 " 1.0 (cont'd) Rubber Composition (mixing ratio) Sample Cobalt StearateSulfur Vulcanization Accelerator No. Amount Amount ~YE~ Amount (pts. by wt.)(pts. by wt.) (pts. by wt.) 44 0 6.0 C 1.0 0 7,0 ~ 1.0 46 0.5 2.5 " 1.0 47 0.5 6.5 " 1.0 48 2.0 8.0 " 1.0 49 4.0 9.0 " 1.0 6.0 6.0 " 1.0 51 7.0 4.0 " 1.0 52 7.0 10.0 n 1.0 * A: N-Oxydiethylene-2-benzothiazolylsulfenamide (Invention) B: N-tert-Butyl-2-benzothiazolylsulfenamide (Invention) C: N,N-Dicyclohexyl-2-benzothiazolylsulfenamide (Comparison) Subsequently, steel cords (1 x 5/0.25) were plated with alloys having the compositions shown in Table 3.
Composition of Plating Steel Cord Alloy (wt%) Sample No. Copper Zinc Nickel Remarks A 65 35 0 Comparison B 65 33 2 Invention C 65 31 4 "
D 65 29 6 "
E 65 27 8 "
F 65 25 10 "
H 65 5 35 "
The rubber compositions shown in Table 2 were combined in various ways with the steel cords shown in Table 3 and the resulting mixing compositions were vulcanized under predetermined conditions, followed by aging under the conditions shown in Table 4. Thereafter, the rubber material was peeled apart mechanically from the cords and the peel force, i.e., the force required to cause separation between the rubber and the cord, was measured. At the same time, the state of rubber adhered to the surface of cords was visually evaluated on a 10-point scoring basis. The results are shown in Table 5, as well as in Table 6. The greater the values shown in these tables, the better are the results.
Aging Condition Aging Relative ConditionTime Temperature Humidity (hr) (C) (%) (a) 0 -- __ (b) 400 80 95 (c) 24 120 100 (d) 96 120 --Condition (a) was used for measuring the initial strength of adhesion; conditions (b) and (c) were used for measuring wet heat resistance; and condition (d) was used for measuring heat resistance.
Among the combinations shown in Table 5 and Table 6, those consisting of Rubber Composition Samples 1 to 18 and Steel Cord Samples B to H provided composite materials within the scope of the present invention.
Table 5 shows the results of visual evaluation of rubber adhesion on a 10-point scoring basis and the greater the values shown in these tables, the better are the results.
Table 6 shows the results of measurements of peeling force.
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m ~ a ~ ~ ~ s 1 The composite materials prepared in accordance with the present invention exhibited satisfactory results under all of the conditions employed. Rubber Composition Nos. 1 to 3, 7 to 9, and 13 to 18 enabled the preparation of composite materials that ensured satisfactory adhesion without employing any cobalt salt of organic acids. This advantage was especially noticeable when the rubber compositions specified above were combined with Steel Cord Samples C to F.
The composite material of the present invention ensures improved adhesion between a rub,ber material and a metal material throughout the period of its use including from the initia~ stage to after aging by heat or wet heat. In addition, this composite material solved all of the problems conventionally encountered during production such as environmental pollution and rubber scorching.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
Claims (5)
1. A composite material comprising a rubber composition and a metal material, wherein said rubber composition contains, per 100 parts by weight of rubber, 0 to 0.5 part by weight of a cobalt salt of an organic acid, 3 to 6 parts by weight of sulfur, and N-oxy-diethylene-2-benzothiazolylsulfenamide or N-tert-butyl-2-benzothiazolylsulfenamide as a vulcanization accelerator, and said metal material is provided with a plating of a ternary alloy consisting of copper, zinc, and nickel, wherein said ternary alloy contains not greater than 75 weight per cent copper and not greater than 10 weight per cent nickel.
2. A composite material as claimed in Claim 1, wherein said ternary alloy consists of 60 to 75 weight per cent copper, 4 to 10 weight per cent nickel, and the balance being zinc.
3. A composite material as claimed in Claim 1 or 2, wherein said vulcanization accelerator is present in an amount of 0.5 to 2 parts by weight per 100 parts by weight of rubber.
4. A composite material as claimed in Claim 1 or 2, wherein said cobalt salt of an organic acid contains 8 to 10 weight per cent of cobalt in the salt.
5. A composite material as claimed in Claim 1 or 2, wherein said rubber composition contains no cobalt salt of the organic acid.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63279867A JPH01259040A (en) | 1987-11-07 | 1988-11-04 | Composite material |
| EP88310453A EP0318171B1 (en) | 1987-11-07 | 1988-11-07 | Composite material |
| DE8888310453T DE3867044D1 (en) | 1987-11-07 | 1988-11-07 | COMPOSITE. |
| CA000606310A CA1336740C (en) | 1987-11-07 | 1989-07-21 | Composite material |
| US07/842,802 US5200273A (en) | 1987-11-07 | 1992-02-28 | Metal composite of rubber, benothiazole sulfenamide and copper alloy |
| US07/884,894 US5284713A (en) | 1987-11-07 | 1992-05-18 | Composite material of metal and rubber |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28177787 | 1987-11-07 | ||
| JP30809387 | 1987-12-04 | ||
| JP63279867A JPH01259040A (en) | 1987-11-07 | 1988-11-04 | Composite material |
| CA000606310A CA1336740C (en) | 1987-11-07 | 1989-07-21 | Composite material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1336740C true CA1336740C (en) | 1995-08-22 |
Family
ID=27426692
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000606310A Expired - Fee Related CA1336740C (en) | 1987-11-07 | 1989-07-21 | Composite material |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1336740C (en) |
-
1989
- 1989-07-21 CA CA000606310A patent/CA1336740C/en not_active Expired - Fee Related
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