JP2001354005A - Tire reinforcing member, and pneumatic tire using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire reinforcing member which can considerably improve the degradation-resistant adhesivity without impairing the initial adhesivity between a steel cord and a coating rubber and also considerably improve the durability of a pneumatic tire, and the pneumatic tire using the member. SOLUTION: In a layer comprising at least one composite layer comprising a coating rubber component and the steel cord, or a layer comprising (a) at least one composite layer comprising the coating rubber component and the steel cord and (b) at least one rubber component layer adjacent to the composite layer, the basic inorganic filler is blended in at least one rubber component layer constituting the layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire reinforcing member and a pneumatic tire using the same, and more particularly to a composite comprising a steel cord and a coating rubber, or a rubber such as a squeegee rubber and the composite. The present invention relates to a tire reinforcing member made of a laminate with a composition layer, and a pneumatic tire to which the tire is applied and having improved durability.

[0002]

2. Description of the Related Art Generally, a steel cord is used as a reinforcing member in a pneumatic tire, and a composite composed of a rubber composition and a steel cord is used for a carcass ply, a belt, a breaker, or the like. It is also common practice to improve the durability of the pneumatic tire by increasing the fatigue durability of the cord layer by laminating a so-called squeegee rubber between the plies. In such a composite of steel cord and coating rubber, if the adhesive layer between the steel cord and rubber is destroyed by the heat generated by running the tire, a fatal tire failure may occur. It is desired to further improve the adhesiveness between them. For this reason, conventionally, an organic acid cobalt salt is usually blended into a coating rubber composition in contact with a steel cord as an adhesion promoter in order to increase the adhesive strength with the steel cord. In addition, rubber members made of various compounds are arranged around the coating rubber, and various compounding agents are transferred from the peripheral members into the coating rubber during long-term running, and steel cord and the like are contained therein. Although it is considered that a substance which has an adverse effect on the adhesive layer with rubber is also contained, it is a fact that the conventional method does not sufficiently consider this point. Recently, the present applicant has proposed a method of inactivating an organic acid metal salt by adding a specific water-resistant acid acceptor to a coating rubber in which a steel cord is embedded to improve the adhesion durability (Japanese Patent Application Laid-Open (JP-A) No. 2002-110630). 2000-17115). However, in such a method, when a large amount of an acid acceptor is added, sulfur and a vulcanization accelerator in the coating rubber composition are simultaneously captured during vulcanization, so that both the initial adhesion and the deterioration-resistant adhesiveness It turned out that sufficient performance was not obtained.

[0003]

SUMMARY OF THE INVENTION Under such circumstances, the present invention provides a method for improving the durability of a pneumatic tire by significantly increasing the degradation resistance without deteriorating the initial adhesion between the steel cord and the coating rubber. It is an object of the present invention to provide a tire reinforcing member capable of greatly improving the durability and a pneumatic tire to which the durability is applied by using the member.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, it has been found that a basic inorganic filler is compounded in a rubber composition layer constituting the laminated member. It has been found that it can be adapted to the purpose. The present invention has been completed based on such findings. That is, the present invention provides (a) at least one composite layer composed of a rubber composition and a steel cord, or (a) at least one composite layer composed of a coated rubber composition and a steel cord, and (b) the composite. In a laminate comprising at least one rubber composition layer adjacent to a layer, a tire reinforcing member is provided, wherein a basic inorganic filler is blended into at least one rubber composition constituting the reinforcing member. Things. The present invention also provides a pneumatic tire using the tire reinforcing member.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The tire reinforcing member of the present invention can be suitably used for truck / bus tires and large off-road tires. The tire reinforcing member of the present invention used herein comprises (a) at least one composite layer composed of a rubber composition and a steel cord, or the composite layer (a) and (b) the composite layer. And at least one rubber composition layer adjacent to the tire, and is particularly preferably applied to a carcass and a belt of a tire. In the tire reinforcing laminated member of the present invention, the composite layer and the rubber composition layer may each be a single layer or two or more layers, and when two or more layers are included, they are alternately arranged. Is also good. 1 (a) to 1 (c) show a basic layer structure of a tire reinforcing laminated member of the present invention. In the laminated member of FIG. 1A, a rubber composition layer 3 is laminated on one outer surface of a composite layer 4 composed of a steel cord 1 and a coating rubber composition 2. When further adding a composite layer here, for example, as shown in FIG. 1B, two composite layers 4 may be continuously laminated. FIG. 1 (c)
As shown in (1), the rubber composition layer 3 may be interposed between two adjacent composite layers 4. A plurality of these basic structures can be combined and stacked. In addition,
It is preferable that at least one outer surface of the laminated member for reinforcing a tire of the present invention is a rubber composition layer. The thicknesses of the composite layer 4 and the rubber composition layer 3 are not particularly limited, and can be appropriately determined according to the size and use of the tire using the tire reinforcing member of the present invention.

In the present invention, it is necessary to blend a basic inorganic filler into the rubber composition constituting at least one layer of the tire reinforcing member. Specific examples of the basic inorganic filler include metal oxides such as MgO, CaO and Al ₂ O ₃ ; metal carbonates such as MgCO ₃ and CaCO ₃ ; complex bases such as talc, kaolin and hydrotalcite compounds. And the like. Among these, the general formula _{(I): [(M 1} 2+) (1-x) (M 2 3+) x (OH -) 2] x + · [(A n-) x / n · mH 2 O] ^x- (I) (wherein, M ₁ ²⁺ is a divalent metal cation, M ₂ ³⁺ is a trivalent metal cation, a ^n-n-valent anion, x is 0 <x ≦ 0. 5
And m represents 0 or a positive number. ) Are preferable.

Here, M₁ ²⁺As Mg²⁺, Mn²⁺,
Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺Bivalent, such as
Cations, particularly Mg²⁺Preferably
No. M₁ ³⁺As Al³⁺, Fe³⁺, Cr³⁺, Co³⁺,
In³⁺And other trivalent metal cations. Also, A
^n-As OH^-, F^-, Cl^-, Br^-, NO_Three ^-, CO _Three
^2-, SO_Four ^2-, Fe (CN)₆ ^3-, CH_ThreeCOO^-, Shu
N-valent anions such as acid ions and salicylate ions
And especially CO_Three ^2-It is preferred that The general formula
As a hydrotalcite compound represented by (I)
Is, for example, Mg_4.3Al_Two(OH)_12.6CO_Three・ M'H_TwoO
(When x = 0.315 in the general formula (I))
Or a compound obtained by calcining it to remove water of crystallization [Kyowa
Chemical Industry Co., Ltd.]
Wear.

When the basic inorganic filler is blended in the rubber composition layer, its content is determined by the rubber component 10 in the rubber composition layer.
It is preferably in the range of 0.1 to 20 parts by weight per 0 parts by weight. If this content is less than 0.1 part by weight, the effect of improving the adhesive deterioration resistance is not sufficiently exhibited, and if it exceeds 20 parts by weight, the fracture resistance, fatigue resistance and workability of the vulcanized rubber composition are reduced. Sometimes. Considering the adhesive deterioration resistance, fatigue resistance, workability, and the like, the preferred content of the basic inorganic filler is in the range of 0.5 to 10 parts by weight. When the basic inorganic filler is compounded in the coating rubber composition of the steel cord / rubber composition composite layer, the compounding amount is from 0.1 to 100 parts by weight of the rubber component in the coating rubber composition. 5 parts by weight is preferable from the viewpoint of improving the durability of the tire. A more preferred amount is 0.1 to 2 parts by weight.

The rubber component used in the coating rubber composition constituting the composite layer and the rubber composition constituting the rubber composition layer of the present invention include natural rubber and synthetic rubber. Examples of the synthetic rubber include butadiene rubber (BR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butyl rubber (IIR), halogenated butyl rubber, preferably brominated butyl rubber, and butyl rubber having a paramethylstyrene group (specifically, Such as a copolymer of isobutylene and p-halogenated methylstyrene), ethylene-propylene-diene rubber (EPDM)
And the like can be mentioned as preferable ones. The rubber component is appropriately selected from one or more of natural rubber and the synthetic rubber according to the use of a rubber product using a steel cord as a reinforcing material. In view of the above, a rubber component containing 50% by weight or more of natural rubber and / or synthetic isoprene rubber is preferable.

[0010] The rubber composition is generally blended with various adhesion promoters conventionally used in steel cord adhesive rubber compositions. Preferred examples of the adhesion promoter include metal salts of organic acids, particularly cobalt salts of organic acids. Here, the organic acids are saturated,
It may be unsaturated, linear or branched, and for example, naphthenic acids such as cyclohexanoic acid (cyclohexanecarboxylic acid) and alkylcyclopentane having a fatty acid side chain; hexanoic acid, octanoic acid, decanoic acid (neodecanoic acid) And saturated fatty acids such as dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid; unsaturated fatty acids such as methacrylic acid, oleic acid, linoleic acid, and linolenic acid; rosin, tall oil acid, and abieticin And resin acids such as acids. Further, a part of the metal of the organic acid metal salt can be replaced with a compound containing boron, boric acid, aluminum or the like. As the compounding amount of the metal salt of the organic acid, with respect to 100 parts by weight of the rubber component, as the metal element content,
It is preferable to add 0.1 to 0.3 parts by weight. Further, in the rubber composition layer adjacent to the composite layer of the steel cord and the coating rubber, it is preferable to mix these adhesion promoters as in the case of the coating rubber.

The rubber composition of the present invention usually contains sulfur. This sulfur content is the same as that of rubber component 1
The range of 3 to 8 parts by weight per 00 parts by weight is preferred. If the content is less than 3 parts by weight, Cu, which is a source of adhesive strength
_x S (produced by reaction between copper and sulfur in the brass plating of the steel cord.) can not provide sufficient sulfur to generate, it may become insufficient adhesion. Further, when the content exceeds 8 parts by weight, Cu _x S is excessively generated, so that the cohesive failure of the enlarged Cu _x S occurs, the adhesive strength decreases, and the heat aging resistance of the coating rubber composition tends to decrease. Be looked at.

Further, in addition to the above-mentioned components, a compounding agent usually used in the rubber industry is added to the coating rubber composition in the tire reinforcing member of the present invention and the rubber composition constituting the rubber composition layer adjacent thereto. Can be appropriately blended in a usual blending amount. Specifically, fillers such as carbon black, zinc white and silica, softeners such as aroma oil, guanidines such as diphenylguanidine, thiazoles such as mercaptobenzothiazole; N, N'-dicyclohexyl-2-benzothia Vulcanization accelerators such as sulfenamides such as zolylsulfenamide, thiurams such as tetramethylthiuram disulfide, poly (2,
Antioxidants such as amines such as 2,4-trimethyl-1,2-dihydroquinoline) and phenyl-α-naphthylamine.

Further, the steel cord applied to the laminated member of the present invention is plated with brass, zinc, or an alloy containing nickel or cobalt in order to improve the adhesion layer with rubber. Preferably, those subjected to a brass plating treatment are particularly suitable. When the content of Cu in the brass plating of the steel cord is 75% by weight or less, preferably 55 to 70% by weight, good and stable adhesion can be obtained. The twist structure of the steel cord is not particularly limited.

Next, the pneumatic tire according to the present invention comprises:
A pneumatic tire to which the above-mentioned tire reinforcing member is preferably applied as a carcass and / or belt member. The reinforcing member comprises (a) a composite layer composed of a steel cord and a rubber composition, or (a) at least one composite layer composed of a ply-coated rubber covering the steel cord; and (b) the composite It consists of at least one rubber composition layer (for example, so-called squeegee rubber) adjacent to the body layer. In addition, the composite layer may be a single layer or a multiple layer, but preferably has one or two layers for a carcass and two to six layers for a belt. Such a tire reinforcing member of the present invention is a construction vehicle tire, that is,
It is preferably used for large off-road tires and truck / bus tires, such as tires for dumps, loaders, and scrapers, in which the deterioration resistance between the steel cord and the coating rubber is particularly important due to the normal thickness, such as tires for trucks and buses.

The production of the rubber composition, the steel cord-coated rubber composite, the laminated member and the pneumatic tire described above do not require any special steps, and are carried out by methods well known in the rubber and tire industries.

[0016] The stem-containing tire of the present invention can be filled not only with air but also with a stable gas such as nitrogen.

[0017]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, evaluation of the initial adhesiveness and the degradation resistance adhesiveness of the prototype tire used below was performed as follows. (1) Initial adhesiveness A carcass ply was cut out from the shoulder portion of the tire after vulcanization to prepare a sample. Using this sample,
At 90 ° C., the steel cord was pulled out, and a portion (area) covered with rubber on the surface of the pulled out steel cord was determined as a ratio to the entire surface of the cord, and this was defined as a rubber adhesion amount (%). The higher the value, the better. (2) Degradation-resistant adhesion After the vulcanized tire was kept at 100 ° C. for 15 days, it was tested in the same manner as in the above (1) to determine the rubber adhesion amount (%). The higher the value, the better.

Examples 1 to 6 and Comparative Examples 1 and 2 Tire sizes of 11R22.5 were used for trial production of truck / bus tires having four belt layers by an ordinary method. The steel cord as a reinforcing material for the carcass ply of this tire is made of brass plating (Cu: 63% by weight, Zn:
37% by weight), 3 + 9 + 1 structure, strand diameter 0.23mm
It was. Further, in Examples 1 to 5 and Comparative Example 1, the carcass ply of the tire was composed of one composite layer composed of a steel cord and a coating rubber composition covering the same, and one rubber composition adjacent to the composite layer. In Example 6 and Comparative Example 1, a composite layer composed of a steel cord and a coating rubber composition covering the steel cord was used as a laminated member composed of a material layer (squeegee rubber).

Compounded rubbers A to E were used as the coating rubber composition constituting the composite layer of the carcass ply of the tire and the rubber composition of the rubber composition layer adjacent thereto. Compounding of compounded rubber A is 100 parts by weight of natural rubber, 55 parts by weight of carbon black FEF, 1.0 part by weight of softener,
2.0 parts by weight of cobalt naphthenate, 6 parts by weight of zinc oxide,
Anti-aging agent N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine [manufactured by Ouchi Shinko Chemical Co., Ltd., trade name: Nocrack 6C] 2 parts by weight, sulfur 5
Parts by weight, vulcanization accelerator N, N'-dicyclohexyl-2-
Benzothiazolylsulfenamide (Ouchi Shinko Chemical Co., Ltd., trade name: Noxeller DZ) was 0.8 parts by weight. Using this composition as a basic composition, as shown in Table 1,
Hydrotalcite (Kyowa Chemical Industry Co., Ltd., trademark: KW-2200) or MgO was blended in a predetermined amount as a basic inorganic filler to prepare compounded rubbers B to E, respectively.

Table 1 Types (parts by weight) of rubber mixed with basic inorganic filler ABCDE hydrotalcite- 0.55 10- MgO----1

Table 2 shows the combinations of the coating rubber (composite layer) and the squeegee rubber (rubber composition layer) used for the carcass layer of each prototype tire.

Each of the tires thus produced was evaluated for initial adhesion and deterioration-resistant adhesion by the above-described method. The results are shown in Table 2.

Table 2 Example Comparative Example 1 2 3 4 5 6 1 2 Composition of Carcass Ply Coating Comb / Skiing Comb A / BA / CA / DA / EB / BB / None A / AA / None Initial adhesion ( %) 95 95 95 95 90 90 95 95 Deterioration resistance (%) 40 55 65 45 50 50 10 10

As can be seen from Table 2, the tire of the present invention in which the carcass layer in which hydrotalcite is blended with rubber is applied has both excellent initial adhesion and deterioration resistance.

[0025]

EFFECTS OF THE INVENTION The tire reinforcing laminated member of the present invention can greatly increase the deterioration-resistant adhesiveness without impairing the initial adhesiveness between the steel cord and the coating rubber composition, so that the durability is greatly improved. An improved pneumatic tire can be provided.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing an example of a tire reinforcing laminated member of the present invention. FIG. 1B is a cross-sectional view showing another example of the tire reinforcing laminated member of the present invention. FIG. 1C is a cross-sectional view showing still another example of the tire reinforcing laminated member of the present invention.

[Explanation of symbols]

 1: steel cord 2: coating rubber composition 3: rubber composition layer 4: composite layer

Claims (9)

[Claims] 1. A tire reinforcing member comprising at least one composite layer comprising a coating rubber composition and a steel cord, wherein a basic inorganic filler is blended into the coating rubber composition. 2. A laminate comprising: (a) at least one composite layer comprising a coating rubber composition and a steel cord; and (b) at least one rubber composition layer adjacent to the composite layer. A tire reinforcing member, wherein a basic inorganic filler is blended into at least one layer of the rubber composition constituting the laminate. 3. A basic inorganic filler is compounded in a coating rubber composition, and the compounding amount is 0.1 to 5 parts by weight per 100 parts by weight of a rubber component in the coating rubber composition. The member for reinforcing a tire according to claim 1. 4. A basic inorganic filler is compounded in the rubber composition constituting the adjacent rubber composition layer, and the compounding amount is 0.1 to 100 parts by weight of the rubber component in the rubber composition.
The tire reinforcing member according to claim 2 or 3, wherein the amount is 1 to 20 parts by weight. 5. The basic inorganic filler, the general formula ^{_{(I) [(M 1 2+}} ) (1-x) (M 2 3+) x (OH -) 2] x + · [(A n-) x ^{_{/ n · mH 2 O] x-}} (I) ( wherein, M ₁ ²⁺ is a divalent metal cation, M ₂ ³⁺ is a trivalent metal cation, a ^n-n-valent anion, x is 0 <X ≦ 0.
The number satisfying 5, m represents 0 or a positive number. 5. The member for reinforcing a tire according to any one of claims 1 to 4, comprising a hydrotalcite compound represented by the formula (1) and a calcined product thereof. 6. The tire reinforcing member according to claim 2, wherein at least one of the outermost layers is a rubber composition layer. 7. A pneumatic tire using the tire reinforcing member according to any one of claims 1 to 6. 8. The pneumatic tire according to claim 7, wherein the tire reinforcing member is used in at least one of layers constituting a carcass and a belt. 9. The pneumatic tire according to claim 7, wherein the tire is a large off-road tire.