Chemistry: electrical and wave energy – Processes and products – Electrostatic field or electrical discharge
Patent
1993-06-22
1995-05-02
Gorgos, Kathryn
Chemistry: electrical and wave energy
Processes and products
Electrostatic field or electrical discharge
428364, 428375, 428359, 428395, 428371, 428373, 4274346, 427538, 427539, 5253319, 528480, 528483, 564463, 57902, H05F 300
Patent
active
054116384
DESCRIPTION:
BRIEF SUMMARY
CROSS-REFERENCE TO RELATED APPLICATIONS
U.S. Pat. No. 5,246,776 is hereby incorporated by reference in the present application.
BACKGROUND OF THE INVENTION
The present invention relates to fibers of aromatic polyamides such that at least 85% of the amide linkages (--CO--NH--) are joined directly to two aromatic rings, these fibers being currently known as "aramids".
More particularly, the invention relates to the bonding of these aramid fibers to rubber compositions. U.S. Pat. No. 5,246,776, which is incorporated by reference in the present application, describes aramid monofilaments having both a large diameter and high mechanical characteristics in the as-spun condition.
These monofilaments are characterized by the following relationships:
Ti being the linear density in tex, D being the diameter in .mu.m (micrometers), T being the tenacity in cN/tex, and Mi being the initial modulus in cN/tex.
SUMMARY OF THE INVENTION
The object of the invention is to propose a treatment which makes it possible to obtain good adhesion of these monofilaments to rubber compositions.
Accordingly, the method of the invention for treating at least one aramid fiber so as to promote its adhesion to rubber is characterized by the following points:
(a) at least one monofilament is used which satisfies the following relationships:
Ti being the linear density in tex, D being the diameter in .mu.m (micrometers), T being the tenacity in cN/tex, and Mi being the initial modulus in cN/tex;
(b) this monofilament is subjected to a surface treatment by plasma in such a manner that the monofilament has a wettability by water which satisfies the relationship W.sub.SL .gtoreq.120,
W.sub.SL being the reversible solid-liquid adhesion work expressed in mJ/m.sup.2.
The monofilament treated in this manner is preferably then subjected to an adhering treatment employing two successive coating baths before being contacted with a rubber composition.
The invention also relates to an aramid monofilament characterized by the following relationships:
Ti being the linear density in tex, D being the diameter in .mu.m (micrometers), T being the tenacity in cN/tex, and Mi being the initial modulus in cN/tex; W.sub.SL being the reversible solid-liquid adhesion work expressed in mJ/m.sup.2.
The monofilament of the invention can be used, either by itself or in the form of assemblages, for instance to reinforce articles, in particular articles of plastic and/or rubber, such articles being for instance belts, hoses, or automobile tires, the invention also covering these assemblages and articles reinforced in this manner.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention will be easily understood on the basis of the following examples:
I. DETERMINATION OF THE CHARACTERISTICS
1. Conditioning
By conditioning there is understood in the present specification the treatment of the monofilaments and assemblages in accordance with Federal German Standard DIN 53 802-20/65 of July 1979.
2. Linear Density
The linear density of the monofilaments and assemblages is determined in accordance with Federal German Standard DIN 53 830 of June 1965, the products having previously undergone conditioning.
The measurement is effected by weighing out at least three samples, each corresponding to a length of 50 m in the case of a monofilament or to a length of 5 m in the case of an assemblage. The linear density is expressed in tex. It is indicated as Ti for the monofilaments.
3. Diameter
The diameter of the monofilaments is determined by calculation from the linear density of the monofilaments and their density, in accordance with the formula: the linear density in tex, and .rho. representing the density in g/cm.sup.3.
The diameter of the assemblages is measured in accordance with the following method. The assemblage is under tension, this tension being between 0.9 times and 1.1 times the standard pretension, which is 0.5 cN/tex. The assemblage intersects a parallel beam of light. The shadow cast on a bar of photoreceptive diodes is measured instantaneously. The result
REFERENCES:
patent: 4328324 (1982-04-01), Kock et al.
patent: 4469748 (1984-04-01), Sharma
patent: 5246776 (1993-09-01), Meraldi et al.
Testing of Textiles, German Standard, DIN 53834, DK 677.06 1/.062: 620/172, eb. 76 pp. 1-24.
Materials Testing Machines, DIN 51220, UDC 620.1.05 pp. 1-2, Jul. 93.
Tensile Testing Machines, DIN 51221, UDC 620.1.05:620.172, 7-93 pp. Jul. 5.
Compression Testing Machines, DIN 51 223 UDC 620.1.05:620.173; Jul. 94 pp. 1-5.
European Standard, Standard Atmospheres for Conditioning and Testing, EN 20139, Aug. 1992, DIN 53-302, pp. 1-3.
Determination of Count Yarns and Plied Yarns, UDC 677.072.3/.6.620.1/677.017.272, May 1981, DIN 53 830, pp. 1-18.
Bernard Denis
Cornillon Jean-Luc
Compagnie Generale des Establissements Michelin--Michelin & Cie
Gorgos Kathryn
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