Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
1999-07-20
2001-12-11
Copenheaver, Blaine (Department: 1775)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C428S304400, C428S195100, C428S334000, C428S375000, C428S457000, C428S364000, C428S389000, C106S014050
Reexamination Certificate
active
06329073
ABSTRACT:
RELATED APPLICATION
In co-pending European application 96 202 870.0, the priority of which has been invoked, a comparative example 1 on page 16 of the description made mention of a corrosion inhibitor “which was not of the azole type”. The related corrosion inhibiting composition did result in a considerable loss in adhesion. Between brackets, however, it has been added that
The inventors have discovered, however, that with other types of rubber a considerable reduction in adherence loss can be obtained.
In the present application, the inventors disclose their further results in this respect.
FIELD OF THE INVENTION
The invention relates to elongated objects of steel, in particular steel cords, treated with a corrosion inhibiting composition. Another aspect of the invention is a process for treating elongated objects of steel with the corrosion inhibiting composition.
BACKGROUND OF THE INVENTION
Corrosion inhibiting compositions, typically in the form of solutions, suspensions or emulsions are commonly employed in the metal working industry to provide improved corrosion resistance of the metal objects involved. An example of such metal objects is steel cord, which is applied in rubber articles as metal reinforcement. Corrosion of steel cord may occur in the manufacturing process, during storage and transport of the steel cord as well as during and after the application of the steel cord in the rubber articles. In this respect it is remarked that always a certain amount of moisture is present in said rubber articles whereas additional moisture may penetrate the rubber articles by way of diffusion and in particular by way of hair cracks and other imperfections.
In the prior art many corrosion inhibiting compositions have been used. For instance, in DE-A 2.704.190 a method is disclosed for improving the corrosion resistance of steel cord coated with Zn, brass or bronze layer by dipping it just long enough in a sodium nitrite or potassium nitrite solution for moistening to occur and then drying it at a temperature below 150° C.
Another method for providing corrosion protection to steel cord to be embedded in rubber articles like tires is disclosed in JP 02227304 A2. According to said document the tires have interior layers containing water-absorbing polymers and exterior layers of halobutyl rubbers.
Further it is known to apply a corrosion inhibiting composition, comprising specific reaction products like the product 6[2,4-bis(allylamino)-s-triazin-6-ylamino]-2-mercaptobenzothiazole as disclosed in Example 10 (B) of EP 331279 A2 to brass coated steel cord.
As apparent from the above it is known from the prior art to apply corrosion inhibiting compositions to steel cord resulting in an improved corrosion resistance of the treated steel cord. However, such an improvement of the corrosion resistance may result in a considerable loss of the adherence between the steel cord and the rubber comprising the steel cord as a reinforcing means.
U.S. Pat. No. 5,221,490 discloses a rust-preventive lubricant composition useful for zinc-plated steel materials in the form a sheet or strip. The composition of the invention comprises a lubricant component and a rust-inhibiting component with a composition comprising at least one member selected from sulphonates (C≧16), carboxylic acids (C≧12), and salts of carboxylic acids.
U.S. Pat. No. 4,201,681 discloses a metalworking lubricant composition which is both effective as corrosion inhibitor and as drawing lubricant and which comprises a mineral oil and a barium sulphonate.
GB-A-2 157 310 discloses a lubricating and anti-corrosion composition for treating metal such as steel sheets. The composition comprises a mineral oil, a basic calcium salt of an alkylaryl sulphonic acid, a further anti-corrosion agent and a saturated C
12-18
fatty acid.
JP-A-53-090 454 discloses a steel cord for reinforcement of rubber products coated with brass and with a solution prepared by dissolving a percentage of barium dinonyl naphtalene sulphonate in mineral oil.
In view of the above the invention is directed to a method for avoiding the above disadvantage, i.e. to develop a corrosion inhibiting composition which decreases the level of corrosion of the steel cord and hardly affects the adherence between the reinforcing means made of steel like a tire cord and some types of rubber. Further the invention should particularly relate to compositions which are environmentally acceptable.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided an elongated object of a steel partly or fully in the form of a hard drawn steel wire of in the form of a steel cord with such steel wires. The steel object is covered with a coating layer having an electrode potential exceeding the electrode potential of steel or having a rate of corrosion which is lower than the rate of corrosion of steel. The elongated steel object is treated with a corrosion inhibiting and adhesion retention composition, which comprises
A) an oily or waxy carrier:
B) active components comprising
B1) a corrosion-inhibitor in the form of a sulphonate of the group IIA,
B2) a co-corrosion-inhibitor, selected from the group consisting of
(a) fatty acids having 6-24 carbon atoms, aromatic acids and naphthenic acids, which acids have the free acid form or the salt form;
(b) imidazoline derivatives having an C
6-24
alkyl moiety; and
(c) C
6-24
alkylsuccinic anhydride compounds;
as well as a mixture of the compounds defined under (a), (b) and or (c) or mixtures of multiple forms of the compounds defined under (a), (b) and (c); and
C) optionally a compound selected from the group consisting of
C1) a water repellent;
C2) a synthetic system derived from a C
1-10
alcohol with 1-12 hydroxyl groups and C
6-24
fatty acids; and
C3) a C
6-18
alcohol
as well as a mixture of compounds defined under C1, C2 and C3 or mixtures of multiple forms of the compounds defined under C1, C2, and C3.
The elongated steel objects may have been covered by a metal or plastic coating which, however, do not coat the steel object completely. A particular metal coating is brass.
The benefits of using the above corrosion inhibiting compositions may be summarized as follows:
(a) the compositions impart steel cord, treated with these compositions, with adequate resistance against corrosion,
(b) the compositions maintain adhesion of some types of rubber to steel cord, treated with these compositions, after embedding said steel cord in rubber and subsequent vulcanizing, to an acceptable level. The compositions do hardly interfere with the delicate physicochemical processes which anchors steel cord to rubber during vulcanization; and
(c) after vulcanization of the rubber in which steel cord is embedded, the compositions according to the invention continue to impart to steel cord some degree of corrosion resistance.
According to a second aspect of the present invention, there is provided a process for manufacturing a corrosion resistant elongated steel object comprising the following steps:
(a) covering a steel wire with a coating layer having an electrode potential exceeding the electrode potential of steel or having a rate of corrosion, which is less than the rate of corrosion of steel;
(b) drawing the steel wire object up to the final diameter; and
(c) at least partly covering the steel wire with a corrosion inhibiting composition as mentioned above.
DETAILED DESCRIPTION OF THE INVENTION
A. The Compositions
The components of the composition according to the invention can be elucidated by the following detailed description.
Carrier
The corrosion inhibiting compositions or corrosion preventives according to the invention typically contain one or more carriers. They are to be considered as the carriers of the active additives and more specifically the corrosion inhibitors. To a certain extent the carrier itself may have corrosion preventing properties, especially due to its hydrophobic character. Carriers may be of mineral, animal, vegetable or synthetic origin. By mixing non-polar with more polar compou
Brabant Johan Van
Deruyck Frank
Copenheaver Blaine
Foley & Lardner
LaVilla Michael
N.V. Bekaert S.A.
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