Rayon Cord Research Articles

The effect of K-1 brightener on the coefficient of fibre strength utilization in viscose rayon cord during the twisting process

The effect of K-1 brightener on the coefficient of fibre strength utilization in viscose rayon cord during the twisting process

The influence of surfactants on the adhesion properties of viscose rayon cord

The influence of surfactants on the adhesion properties of viscose rayon cord

The temperature of the spinning bath as a factor in the structure and physico-mechanical properties of cord rayon

The temperature of the spinning bath as a factor in the structure and physico-mechanical properties of cord rayon

Sulphate ions in the cord rayon brightener bath determined photometrically with Nitkhromazo as indicator

Sulphate ions in the cord rayon brightener bath determined photometrically with Nitkhromazo as indicator

Improving the properties of cord rayon with structuration additives and inhibitors of thermo-oxidative degradation

Improving the properties of cord rayon with structuration additives and inhibitors of thermo-oxidative degradation

Localizing noxious gas liberation in the production of cord rayon

Localizing noxious gas liberation in the production of cord rayon

Cord Force Measurements in Radial Tires

Miniature force transducers in the form of strain gage instrumented tension links are used to measure the loads developed in the rayon cords in both the stabilizer and body plies of automobile tires of radial construction. These transducers are placed in series with the cord and are embedded in the rubber matrix of the tire during building. Cord forces are obtained at various wheel loads and inflation pressures for straight ahead rolling and cornering of the tires in operation. It is shown that a relatively simple formula can be used to theoretically predict the cord tension developed in the sidewall region due to inflation pressure.

Viscoelastic Properties of Truck Tire Compounds and the Related Heat Build-Up

Abstract Rubber compounds used in the manufacture of tread-cap, tread-base, and for the rubber-coating of the rayon cord for 12.00–20 tires have been varied in composition and, in consequence, their viscoelastic properties have been altered. Operating temperatures, in test-wheel runs, have been measured in the shoulder region of the tire close to the casing, using a needle-thermocouple. Multiple-regression has been used to investigate which combinations of viscoelastic properties of the rubber vulcanizates would give a linear, significant correlation to the heat build-up in the tire with a minimum residual. From the nature of the variables in the regression functions, conclusions have been drawn on the type of load occurring in the different components of the tire. It was found that the tread cap contributed to the heat build-up according to its loss compliance E″/|E*|2 and the carcass according to its loss-factor, E″/E′. Thus, the statistics show that the greater contribution to the heat build-up comes from the tread-base, according to its loss-factor also. The values of temperatures, calculated by the multiple-regression, show deviations of only a few degrees centigrade compared to the average temperatures of tires of the same construction. Therefore the operating temperatures of tires to be expected as a result of the compound variations can be estimated in advance. On individual tires greater deviations, up to 10°C, have been measured. These are due to inevitable inaccuracies in tire building and errors in temperature measurements.

The fatigue properties of viscose rayon cord yarn containing structure-forming and thermo-oxidation inhibiting additives

The fatigue properties of viscose rayon cord yarn containing structure-forming and thermo-oxidation inhibiting additives

Mechanical properties of metal matrix composites

Abstract The concept of reinforcing a material by the use of a fiber is not a new one. The Egyptian brick layer employed the same principle more than three thousand years ago when straw was incorporated into the bricks. More recent examples of fiber reinforced composites are steel-reinforced concrete, nylon and rayon cord reinforced tires, and fiberglass reinforced plastics. In the last several years considerable progress has been made on new composite structures particularly utilizing boron (on tungsten substrate) fibers in various matrices. Many of these advances have been reviewed recently by P. M. Sinclair1 and by Alexander, Shaver, and Withers.2 An excellent earlier survey is available by Rauch Sutton, and McCreight.3 Boron-reinforced epoxy composites are being fabricated and tested as jet engine components, fuselage components, and even as a complete aircraft wing because of the tremendous gain in experimentally demonstrated properties such as modulus, strength, and fatigue resistance, particularly ...

Recent Developments with Tire Cords and Cord-to-Rubber Bonding

Abstract The first pneumatic tire was made in 1888 by J. B. Dunlop with Irish flax as reinforcing material. This fiber was one of the strongest at that time. It was gradually replaced by cotton since Irish flax was expensive. Cotton tire fabrics in the early stages, about 1910, were plain fabrics. As requirements imposed by the severity of tire operating conditions increased, these fabrics were gradually replaced by the present tire cord fabrics, which type of fabric was first devised by J. F. Palmer in 1892. Prior to World War II, cotton was the sole textile used to any large extent in pneumatic tires. However, this cotton tire cord fabric also failed to meet requirements imposed by further increasing severity of tire operations so that tire engineers began to pay attention to man-made fibers. The first rayon tire cord, tenacity about two grams per denier, was produced in 1923. Du Pont started to manufacture high tenacity rayon, Cordura, in 1933, and Courtaulds also started to manufacture high tenacity rayon, Tenasco, in 1936, but by 1940, high tenacity rayons had only a small portion of the total tire cord market. In the late 1940's, use of high tenacity rayon tire cords increased rapidly in the United States and Europe. In Japan, rayon truck tires were first manufactured in 1951. Initially rayon cords were used only for truck tires. The rayon cord tire had improved carcass performance and its life was increased 30 to 60%. This improvement of tire quality was utilized more for truck tires than for passenger car tires. Increased power of automobile vehicles, however, gave birth to troubles in rayon cord (truck) tires. New, tougher materials were required for tire cords especially for heavy duty tires. In 1947, nylon cords (nylon 66) were examined as reinforcing materials for truck tires in the United States, and it was confirmed that nylon truck tires have excellent properties especially under severe operating conditions. In the late 1950's, rayon cords were gradually replaced by nylon cords, especially in the United States. Japanese tire manufactures made extensive efforts to use nylon 6 for tire cords. Nylon 6 was available from domestic suppliers, (nylon 66 was more costly) and nylon 6 tires, when post cure inflation was used, showed no difference from nylon 66 tires in practice. Mass production of nylon tires in Japan started in 1958. In the first five years, 60% of all tire cords had been replaced by nylon cords. In 1967, per cent nylon cord use was up to 90% in Japan. On the other hand, in Europe, rayon cord still has a greater portion of the tire cord market. Goodyear started to produce polyester tires as passenger car tires in 1962. In recent years, production of polyester tires is gradually increasing and their future seems to be promising. Mass production of polyester tires in Japan started in 1967. In both countries, polyester tire producers seemed to desire to penetrate into original equipment tires for passenger cars where rayon cords have been used for many years. Steel cords, which made their appearance in France in 1936, have been used extensively in Europe in radial tires. Glass fiber cords, one of the most promising types for the belt ply of radial tires or belted bias tires, recently appeared in tires in the United States.

STUDIES ON THE HEAT RESISTANCE OF RAYON TIRE CORD

Some factors affecting the heat resistance of high tenacity rayon tire cord have been investigated for the purpose of improving it and results as following were observed:(1) Both raw and RFL-dipped cord of high tenacity rayon suffer heat deterioration by heating in the air atmosphere, but the heat degradation of the latter is more sever than in the former.(2) The higher the copper number of pulp is, the lower is the heat resistance of raw and dipped cord which are made using them as raw materials.(3) By the treatment with the finishing agent containing amines, the heat resistance of the raw cord is improved, but the heat resistance of the dipped cord is not.(4) The remarkable heat degradation of RFL-dipped cord is attributable to the low heat resistance of natural rubbre latex. The heat resistance of the cord is lowered by the adhesion of the unsaturated oil.The heat resistance of the dipped cord is however improved by being dipped in the higher heat resistant synthetic rubber latex, such as Gentac.From these results, it may be considered that the heat degradation of rayon cord is induced by the free radical mechanism.

STUDIES ON THE HEAT RESISTANCE OF RAYON TIRE CORD

Some factors affecting the heat resistance of high tenacity rayon tire cord have been investigated for the purpose of improving it and results as following were observed:(1) Both raw and RFL-dipped cord of high tenacity rayon suffer heat deterioration by heating in the air atmosphere, but the heat degradation of the latter is more sever than in the former.(2) The higher the copper number of pulp is, the lower is the heat resistance of raw and dipped cord which are made using them as raw materials.(3) By the treatment with the finishing agent containing amines, the heat resistance of the raw cord is improved, but the heat resistance of the dipped cord is not.(4) The remarkable heat degradation of RFL-dipped cord is attributable to the low heat resistance of natural rubbre latex. The heat resistance of the cord is lowered by the adhesion of the unsaturated oil.The heat resistance of the dipped cord is however improved by being dipped in the higher heat resistant synthetic rubber latex, such as Gentac.From these results, it may be considered that the heat degradation of rayon cord is induced by the free radical mechanism.

A flywheel impact test for measuring physical properties of tire cords

AbstractThe development and operation of a dynamic tire cord testing apparatus is described. The apparatus consists of a rotating wheel which applies a transverse load to a tire cord and carries it to break. It can be operated at speeds which impact tire cord at velocities of from 10 to 80 ft./sec. The techniques used for detecting, recording, and calculating energy load‐elongation characteristics and time to break are described. Some data showing the effect of impact velocity on the physical properties of nylon, rayon, and polyester tire cords are presented.

STUDY ON THE CRYSTALLINTY OF REGENERATED CELLULOSE FIBRES USING THE X-RAY DIFRACTOMETER

Relative values of the crystallinity of the regenerated cellulose fibres produced by various methods were determined.The hydrolized cotton, which had been mercerized previously, was used as a crystalline standard, and the saponified cellulose acetate in ethyl alcohol as an amorphous standard. It was found that there is an appreciable variation in the crystallinity of regenerated cellulose fibres, depending upon the method of production. Polynosic fibres and cuprammonium rayon are generally highly crystalline, while tire cord rayon generally has a low crystallinity. The amorphous contents of these fibers are approximately proportional to their accessibility determined from their moisture regain. However, a strictly linear relationship between the two values is not observed, since the accessibillity also depends upon the size of the crystalline region. This phenomenon is confirmed by comparing the half-widths of the crystalline peaks.The effect of various treatments on the crystallinity of regenerated cellulose fibers was also studied. It was shown that changes in the crystallinity depend upon the type of fine structures in the original fibers, and that the fine structure in the polynosic fibers is least affected by after treatments, especially with aqueous alkali.

Quantitative Investigation of the X-Ray Diffraction Picture of Some Typical Rayon Specimens

The X-ray diffraction pictures of some typical specimens of highly orientated rayon are studied quantitatively using a dirfractometer technique with Geiger counter detection and strictly monochromatized radiation.The results allow of a more reliable separation between crystalline interferences and background than heretofore possible. The background of orientated rayons is aniso tropic and has a complicated intensity distribution. It has maxima at about 2θ = 21° on the equator and at about 2θ = 35° on the meridian.Evaluation of the intensities of the principal paratropic and diatropic interferences reveals about the same relative differences in crystallinity between the rayons investigated as those given by the method of crystallinity determination employed earlier. Absolute values of the crystalline fraction could not, however, be derived from the present work.The relative intensities of the principal crystalline interferences are measured and found to be in reasonable agreement with those calculated for the Andress lattice struc ture. Some typical deviations are specified.The crystallinity of tire cord rayon was found to be somewhat lower than that of textile rayon and the crystallites in the former somewhat smaller in lateral dimension according to measurements of line width. In the series of specimens investigated there is a correlation between crystallinity and line width. It seems that higher crystallinity tends to go parallel with larger or more perfectly ordered crystallites, a correlation which is also reported to have been observed in other polymers.It is shown that orientation derived from the azimuthal spread of either the diatropic or the paratropic interferences leads to equal results. This is in support of the method developed earlier for quantitative determination of orientation from the paratropic lines in simple exposures on flat film.The outcome of this kind of orientation measurement is but little, almost negligibly, affected by the error involved in assuming the background maximum to lie at the mini mum between the A0and A3peaks and thus at a lower angle and at a slightly higher intensity than the true values.

High Strength Regenerated Cellulose Fibers

Substantial improvements in the physical strength properties of certain fibrous regenerated cellulose products, notably rayon tire cord, have been achieved during the past decade. These advances in tensile and fatigue properties of tire cord rayon are reviewed and the factors responsible for the improvements are discussed in such a manner as to point the way for similar quality gains in related products, such as staple fiber. Improvement in properties is primarily attributed to the combined use of physical and chemical actions to accomplish controlled crystallite development and orientation in the spinning filament. Beneficial use has been made of various types of chemical re generation retarding agents to prolong the plastic-gel state, thereby facilitating heavy stretching along with dehydration of the coagulated filament to yield a highly consoli dated and uniaxially oriented structure prior to complete regeneration. The relation of current spinning practices to mechanical properties attained in the final filament are outlined and interpreted in the light of filament cross-sectional struc ture, secondary swelling properties, and differential dyeing characteristics. Potential strength aims for future cellulosics are discussed and some suggestions made as to the type of products for which the structural skeleton of the cellulose polymer appears to offer outstanding advantages, particularly when coupled with bonding or stabilizing resins in intimate molecular association.

On the Physical Properties of Rayon and Nylon 66 Tire Cords at Elevated Temperature'

Currently produced rayon and nylon tire yarns, greige cords, and dipped cords (the nylon dipped cord having been Kidde treated, hot-stretched, and heat-set) were tested for reversible physical properties at 70°, 100°, 220°, and 300° F. As the temperature was raised, the nylon samples showed greater loss of breaking strength, greater increase in extensibility, greater loss of Hookean slope, and (for the cords) greater increase in con tracting force than the corresponding rayon samples. Heat aging at 220° F. in an air- circulating oven for periods up to five days caused no significant change in the values ob tained at 220° F. for strength, extensibility, or Hookean slope for either the rayon or nylon samples. The rayon cords had the expected advantage of a high initial modulus; this advantage over the nylon cords was improved as the testing temperature was increased from 70°- 300° F. It is believed that this would mean less growth and a smaller degree of cyclic extension, for tires made from the rayon cords, under temperature conditions likely to be met with in normal driving.

タイヤコードの疲労の研究

This paper is an attempt to present an analized picuture of the variation in the mechanical property of tyre cord in relation to the growing of fatigue given by th repeated flexing fatigue test under various load.In the diagram of the tensile strength of cord and numbers of flexing cycle (in logarithms) no change is shown at a certain critical point of fatigue cycle, but over this point the values of tensile strength decrease rapidly and almost linearly with numbers of flexing cycle. The larger the weight of the original static stress is, the lower the limit of flexing cycle is, and the rate of decrease of the tensile strength is smaller with the larger original static stress. The rate of decrease of the tensile strength depends on the types of fibers, e.g., it becomes very slow in High Tenacity Rayon Cord and sharp in cotton and BX Cords.It is found that the limit of decreased tensile strength by flexing cycle (the ultimate strength) is much more than the weight of the original static stress, of which the reason cannot be explained for the present. It is, however, very intesting to know that the above result coincides with following fact, that is, in the case of the practical use the ultimate strength is far greater than the breaking strength of the cord.Variation on impact breaking energy corresponding to the growing fatigue is similar to that in the case of the tensile strength, but the rate that of decrease of impact breaking energy is more greater and the limit of the decrease is lower compared with the rate of decrease of the tensile strength. This suggests that the breaking of the cord is brought from the impact rather than quasi static.The increasing fatigue leads to the breaking of monofilament independently of the tensile strength of the cord, so that there is no change of the tensile strength until the half number of filaments of the cord are broken down. The breaking of monofilament, of course, is most ready to take place at the part where the most frequent flexings are given. It is often observed that at many points single filament is broken down in the flexing parts of the cord. Therefore it comes to the conclusion that the tensile strength depends upon both the strength of monofilament and the frictional force between monofilaments.The decrease of the tensile strength is not so remarkable in both broken monofilament and unbroken one. But the decrease of elongation is distinctly recognized, and the ultimate elongation is a half of the original one. Then it is supposed that the cause for the breaking of monofilament is not due to the decrease of the tensile strength, but is due to the decrease of elongation.

Pull-Through Adhesion Test

Abstract A modified form of the pull-through test is described, followed by a series of experiments, the first three of which demonstrate the precision of the method. Further experiments assess the effect of various factors on the pull-through force. It is found that specimen age has little effect. The tension applied to the cord during construction also produces a small but appreciable effect, amounting to a decrease of 1.3 per cent for a two-fold increase of the tension, but a greater effect, amounting to a 7 per cent increase of the pull-through force, is obtained when the rate of loading is doubled. The pull-through force is also shown to depend on the shape of the mounting device. The twist in a rayon cord does not give a significant effect, though the variability exhibited by the conventionally dipped cord is high. Temperature increase during test reduces the pull-through force; linear plots of the logarithm of the pull-through force against the reciprocal of the absolute temperature are obtained. The cord length embedded in the rubber is shown to bear a hyberbolic relationship to the pull-through force, confirming the theoretical relationship obtained analytically. Finally the pull-through test is considered in terms of the product.