Caroselli, Remus F. (Cumberland, RI)
Mennerich, Fred A. (Cumberland Hill, RI)

05/014727

12/07/1971

02/24/1970

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428/222

428/338, 442/105, 428/401, 57/902, 57/229

D02G3/38; F16C27/06; F16G1/04; F16G1/08; F16G5/06; F16C27/00; F16G1/00; F16G5/00; B32B5/04

161/88-95,152,156 57/140,144,145,152

Burnett, Robert F.

Litman, Mark A.

This application is a continuation of Ser. No. 529,516, filed Feb. 23, 1966, now abandoned.

We claim

1. A continuous composite yarn structure comprising:

2. The composite yarn structure as claimed in claim 1, wherein the glass filaments are of a diameter not exceeding about 0.00015 inch.

3. The composite yarn structure as claimed in claim 1, wherein the organic filaments are selected from the group consisting of cotton, nylon, rayon, polyester and polypropylene.

4. The composite yarn structure as claimed in claim 3, wherein the glass filaments are of a diameter not exceeding about 0.00015 inch.

5. A reinforced article having a principal axial dimension comprising:

6. The invention of claim 5, wherein the glass filaments have a diameter not exceeding about 0.00015 inch, with the glass filaments having greater static length than the organic filaments.

7. The reinforced article of claim 5 wherein the organic filaments are selected from the group consisting of cotton, nylon, rayon, polyester and polypropylene.

This invention relates to novel filament blend products; and more particularly to blended yarns made up of continuous glass filaments twisted about shorter more straight continuous organic filaments of stretchable materials, such as rayon; and to cloths made therefrom.

Organic filaments have substantial stretchability and if not loaded or stretched beyond the yield point can be repeatedly stretched and recovered to their original lengths without permanent deformation. However, if stretched beyond the yield point, these filaments will be deformed, either by permanent elongation, or by breaking.

Glass filaments on the other hand have a very high break strength; much greater than any organic filament. However, glass filaments have very little stretch; practically none.

It is therefore an important object of this invention to combine continuous glass filaments with continuous organic filaments to produce strands having engineered moduli of elasticity, and improved utility.

A further object is to provide yarns made of continuous glass and continuous organic filaments, which yarns have unique and different characteristics from yarns made of the individual materials.

A still further object is to provide woven cloths having unique stretch characteristics and moduli of elasticity.

FIG. 1 is a schematic elevational view of a relatively inextensible glass filament overwrapped on a substantially extensible organic filament, providing a composite yarn of engineered modulus;

FIG. 2 is a schematic illustration of partial tensile loading applied to the structure of FIG. 1; to cause the organic filament to stretch and the glass filament to straighten out;

FIG. 3 is a slightly exaggerated schematic view of the structure of FIG. 1 fully loaded, with the glass filament generally straightened out and the organic filament forced to the outside in the nature of a helical overwrap;

FIG. 4 is a schematic plan view of a first embodiment of a woven cloth made by the present invention;

FIG. 5 is a side elevational view of a reinforced rubber V-belt made according to the present invention;

FIG. 6 is an enlarged perspective sectional view taken along the line 6--6 of FIG. 5;

FIG. 7 is a perspective view, partly in section, of a reinforced rubber hose made according to the invention;

FIG. 8 is a schematic plan view of a second woven cloth made by the present invention;

FIG. 9 is a side elevational view of a reinforced rubber flat belt made with the cloth reinforcement of FIG. 8;

FIG. 10 is an enlarged sectional view taken along the line 10--10 of FIG. 9;

FIG. 11 is a fragmentary elevational view, greatly enlarged, of a shock-absorbing, compression-type composite yarn made according to the invention;

FIG. 12 is a graph illustrating the action of a second shock-absorbing composite yarn made according to the invention, and illustrated in FIG. 13; and

FIG. 13 is a schematic plan illustration of a second type of shock-absorbing yarn made by the invention.

THE INVENTION: PERSPECTIVE VIEW

Briefly, the present invention encompasses continuous filament yarns containing engineered blends of at least one kind of organic filament having a substantial amount of stretch, but relatively low tensile strength on a p.s.i. basis; and continuous glass filaments having very high tensile strength on p.s.i. basis, but relatively low stretch.

Further, the invention encompasses unique cloths woven from these yarns, and several practical structures made therefrom.

In accordance with this invention, glass filaments of very fine diameter can be used. Commercially produced continuous filaments of this type have an average diameter of about 0.00014 inch and in said average include filaments of a diameter in the range from about 0.00018 inch down to about 0.00008 inch. Within the scope of the invention, coarse fibers can be used for some applications.

Denier is the designation of a unit expressing the fineness of silk, rayon, nylon or other yarns in terms of weight in grams per 9,000 meters of length; 100 denier yarn is finer than 150 denier yarn.

To emphasize how fine the specifically mentioned continuous glass filaments are, a comparison is made of the cross-sectional areas of a 1/4-denier glass filament with a 11/2-denier organic filament.

The glass filament is one sixth the denier of the common organic filament. However, since glass has a much higher density than the organic material, the fineness of the glass filament is even greater than that indicated by the denier comparisons. In actual area of cross section for example, the glass filament would be nine times less than that of nylon, polyester or viscose, etc.

These very fine diameter glass filaments are extremely flexible and do not break when bent sharply, as in a weaving operation. Thus, they withstand extremely small radii of bending without breaking.

Durability of glass filaments is related to the tendency of an individual filament to break when subjected to a very sharp bend under conditions of use. It is known that the radius of bend at rupture of glass filament is directly proportional to the diameter of the filament; that is, the smaller the diameter the smaller the radius to which it can be bent before breaking. Thus of two filaments, one being one-half the diameter of the other, the smaller filament can be bent twice as sharply without rupturing.

The fine diameters of these glass filaments and the resistance to fracture are utilized in the present invention by intertwisting the filaments around organic filaments whereby in use the glass filaments withstand flexing, but without breaking.

A further important characteristic of these fine glass filaments is the new magnitude of pliability or softness. They readily conform to surfaces of irregular contour and shape, and thus conform readily to the surfaces of other fibers with which they are blended. Thus the small diameter glass filaments as contemplated herein, readily blend with other filaments without breaking, thereby displaying processability and blendability that distinguishes them from brashy and coarser glass filaments. These finer filaments in fact have such pliability that they actually display gripping tenacity for other filaments.

Actual comparisons of such fine glass filaments with several organic filaments show that the glass is five to 14 times more pliable than the organics. Such conclusions have been derived from cantilever beam and critical buckling load calculations.

Thus, the small glass filaments as contemplated herein readily intertwist with other filaments without breaking, thereby displaying very good processability and blendability that distinguishes them from substantially coarser and more brashy glass filaments.

Within the scope of the invention, the glass filaments can be made from any suitable glass. As a general rule, they are presently being made from high-modulus glass compositions that are relatively low in alkali content.

THE BASIC IDEA BEHIND THE PRESENT INVENTION: FIGS. 1, 2 AND 3

Filaments of relatively stretchable material, and in particular filaments of organic resins such as rayon, nylon, Dacron, (registered trademark for synthetic fiber made by the condensation of dimethyl terphthalate and ethylene glycol), polyesters, polypropylene and polyamides can be combined with glass filaments in such a way that the glass filaments have a slightly larger length dimension than the organic filaments. Cotton can be used also. When twisted or plied together, the glass filaments assume an overwrap configuration on the shorter length organic filaments. This is shown in FIG. 1. In other words the organic filament 20 will assume a generally straight or straighter condition than the longer glass filament 22. The longer glass filament 22 has a tendency to twist around the shorter organic filament 20, due to the high degree of pliability of the glass. As pointed out above, glass filaments of the diameter contemplated by this invention are five to 14 times more pliable than organic filaments.

APPLICATION OF TENSILE FORCE: THIS IS SHOWN IN FIGS. 2 AND 3

When tensile force is applied to the combination yarn 24 it will stretch. Actually the organic filament 20 stretches and the glass filament tends to straighten out. First, as shown in FIG. 2, the organic filament 20 and glass filament 22 acquire a more intertwisted configuration until a balance is reached.

As shown in the exaggerated view of FIG. 3, continued stretching of the composite yarn 24 causes the glass filament 22 to assume a generally straight configuration, where it is fully loaded. The actual ultimate degree of straightening of the glass will depend upon the stretchability of the organic. This forces the more stretchable organic filament 20 to assume a helical overwrap configuration around the glass filament. The organic filament 20 will acquire a slightly lesser diameter due to its stretch.

At this stage the combination yarn is substantially fully loaded. With proper length selection, both filaments 20 and 22 will be loaded to just below the yield point at the stage in FIG. 3. Any further loading will result in simultaneous breakage of both the glass and organic filaments. Utilizing this embodiment, the combination yarn breaks at a load that is approximately the same as the combined breaking strengths of the glass and the organic filaments.

Variations on this theme are possible. Thus by a carefully selected overfeed of the glass relative to the organic filament, the organic can be made to yield, fully break or stretch a limited amount before the glass takes over. An important point is that the organic along can have an elongation of 30 percent (actual for polypropylene) and the composite can have an elongation of only 14 percent, being reduced by the presence of the glass. This is brought about by the fact that the glass has an elongation of only about 3 percent (substantially 2.6 percent). By selecting the amount of overfeed of the glass, the amount of elongation of the composite can be established between the lower limit of the glass and the upper limit of the organic, providing substantial versatility to the invention. Thus, the point here is that by selecting an organic filament with the proper extensibility, and by selecting the relative rate of overfeed of the substantially inextensible glass filament, a combination yarn can be engineered to give any desired elongation characteristic.

It will be recognized that the combination yarn can start from a more balanced structure, containing substantially equal lengths of organic and glass filaments as shown in FIG. 2, to utilize the stress transfer principle to a lesser extent. Accordingly, the stress transfer principle can be designed into the combination to any desired degree over an appreciable range between full stress on the stretchable organic filament to full stress on the glass filament.

Further variations in the composite yarn can be effected-- as by twisting glass filaments and organic filaments together first and then plying these into a yarn. Or, two strands of glass filaments, for example, can be twisted with one organic filament, while only one of the two glass filaments is made slightly longer than the organic.

PRACTICAL APPLICATION NO. 1; THE EMBODIMENT OF FIG. 4; A CLOTH OF UNIFORM, SELECTED DIRECTIONAL STRETCH

In FIG. 4 there is shown a cloth 26 made according to the present invention. The warp (lengthwise) yarns 28 have an exemplary stretch of 10 percent, as by a combination of glass and nylon, with the glass appropriately overfed on the nylon. The filling (crosswise) yarns 30 have an exemplary stretch of about 3 percent. Thus they are made simple of glass filaments to illustrate the limits of the invention. In actual use the warp yarns will elongate when stress is applied in the arrow direction 32, e.g. longitudinally of the cloth 26. Substantially no stress will be encountered however along the arrow line 34, e.g. transversely of the cloth 26.

A REINFORCED RUBBER V-BELT: FIGS. 5 AND 6

In this practical application of the invention, different layers of reinforcement fabric have selectable or different degrees of stretch, depending upon the plane of location within the vertical cross sectional dimension of the belt. Thus, slightly more stretchable yarns are utilized in the outer periphery of the belt 35. For example, the outer ply 36 can be made in the nature of the cloth of FIG. 4. Thus it has 10 percent stretch in the warp yarns 28 or in the longitudinal direction. Nylon, having a stretch of about 20 percent per se, and glass filaments could be used to make the warp yarns 28. There is no need of stretch in the filling yarns 30 and accordingly the filling yarns can be all glass filaments and have a maximum stretch of about 3 percent.

The central ply 38 has an exemplary stretch of 5 percent. Dacron having a maximum stretch of about 15 percent and glass filaments could be used to make the warp yarn 40. Again there is no need of stretch in the filling yarns 30, and accordingly the filling yarns can be all glass filaments; these have a maximum stretch of about 3 percent.

The inner ply 42 will for exemplary purposes be of lowest elongation. This is relied upon to preserve the loop length 44, FIG. 5, of the belt 35. Thus in the inner ply 42 both the warp yarns 46 and the filling yarns 30 are of glass.

The comparative degrees of stretch provided in the belt 35 are illustrated schematically in FIG. 5. Thus the greater magnitude arrow 48 represents the longest stretch of the outer ply 36, FIG. 6; and is proportionally longer than the lesser magnitude arrow 50 representing the lesser stretch of the inner ply 42.

By providing slightly more stretch in the outer periphery of the belt 35, greater flexibility and wear resistance are imparted to the belt, while retaining the desired limited stretch of the entire loop construction, based on a lesser stretch being selectively imparted to the lower planes of the belt.

The plane of least stretch, that is the bottom ply, would be expected to be the reference plane for stretch of the overall belt loop construction. This can be a low degree of stretch or can be maintained the same as the glass filaments per se, as described for the warp threads 46 and the filling yarns 30 of ply 42.

Belts embodying these principles of the invention should display greater durability in compressor drive applications where shock forces are encountered as the compressor piston pulsates through stages of maximum and minimum compression.

APPLICATION TO TUBULAR FORMS; FIG. 7

High-pressure hoses are inherently stiff due to the many plys of reinforcement cloth utilized in their construction. Bending at a sharp radius, in the absence of pliability, is highly damaging to these constructions. By utilizing the principles of the present invention, greater bendability can be provided.

Thus, a fabric in the nature of that illustrated in FIG. 4 would be used to fabricate the outer reinforcement layer 52. The warp yarns 28 (longitudinal) would be oriented axially of the hose form 54 and would have a relatively greater degree of stretch than those of the inner reinforcement ply 56. The amount of stretch in the outer reinforcement ply 52 is indicated by the comparatively greater length of the arrow 58. By making the filling yarns 30 of lesser stretch, i.e. of a higher proportion, or entirely of glass filaments, the radial burst strength of the hose 54 is assured; and antiswelling characteristics are imparted to the structure. By fabricating the inner ply 56 substantially completely of glass filament yarns, the radial burst strength is matched to that of the outer ply.

The comparatively shorter length of the stretch arrow 60 at the bend area of FIG. 7 indicates the need for lesser longitudinal stretch of the inner ply. This is appropriately provided by the all glass filaments or by a higher proportion of glass filament in the warp yarns 46 of the inner ply 56. The filling yarns are as described above, for minimum stretch.

In addition to improved flexibility for bending and handling in use, the longitudinal resilience imparted by the longitudinal stretchability of the hose will counteract the thumping or pulsating action of a compressor. Wear resistance will thereby by substantially increased over the stiff structures of the prior art.

EXTENDED SCOPE OF INVENTION: BANDS OF DIFFERING ZONE STRETCH; FIG. 8

As shown in this Figure of the drawings, the central warp strand 62 has an exemplary stretch of 10 percent. This can be made of composite yarns of nylon filaments having about 20 percent stretch per se and glass filaments having about 3 percent stretch per se. By appropriate overfeed of the glass on the nylon, a 10 percent stretch for the combination can be arrived at.

The intermediate warp strands 64 are shown as having an exemplary stretch of 5 percent. These could be fabricated of a combination of glass filaments and Dacron. Dacron per se has an elongation of about 15 percent and the elongation of about 3 percent of the glass is effective to reduce the composite to about 7 percent with an appropriate overfeed of the glass on the Dacron filaments.

The outer warp strands 66 are shown as having an exemplary stretch of 3 percent. These can be made completely of glass filaments with about 3 percent stretch per se.

The filling yarns 68 are shown as having an exemplary stretch of 5 percent. These can suitably be made of glass filaments and Dacron filaments in blended combination.

USE OF THE CLOTH OF FIG. 8 TO MAKE BELTS; FIGS 9 AND 10

A flat belt 70 as exemplified in these figures in ordinarily used with a crowned pulley 72 having a profile of the nature illustrated in FIG. 10. The center of the crown 74 is of greater diameter than the edges 76. Accordingly, the center of the belt 70 requires greater stretch than the outer edges for appropriate lap on the pulley 72. This is provided in accordance with the present invention. The central warp strands 62 and 64 permit the central portion to elongate over the large diameter of the center of the crown 74. The outer warp yarns 66 have a lesser degree of stretch than the central yarns 62 and 64. This selected zone longitudinal stretchability of the belt 70 causes it to ride the center of the crown 74 in an improved fashion without placing undue wearing stretch on the central warp threads 62 as compared to the lack of comparative stretch in constructions of the prior art.

The outer warp strands 66 being of less stretchability, preserve the loop length of the belt 70.

The filling strands 68 in FIG. 8 have been illustrated as having an exemplary stretch of 5 percent. This helps the belt of FIG. 10 to flex more easily transversely as it rides over the pulleys 72 in reverse curved fashion.

In addition to the advantageous features of crown hugging illustrated in FIG. 10, belts made by this invention can absorb shock forces more readily as in compressor applications.

In summary, a cloth of variable, selected directional zone stretch is provided in accordance with FIG. 8 and a practical application of the same, though not limiting upon the invention, is shown in FIGS. 9 and 10.

A SHOCK-ABSORBING YARN; THE CUSHION-WRAP EMBODIMENT OF FIG. 11

In this aspect of the invention, the inextensibility of the glass filaments is converted into a compressing action against a resilient core of bulky filaments. The central core 78 is suitably made up of a plurality of bulky filaments 80, such as rayon. These can be oriented parallel to one another as illustrated in FIG. 11; or they can be provided in the form of twisted and plied strands, thereby providing a balanced yarn core.

In this embodiment of the invention, opposed glass overwrap filaments or yarns 82 are provided. These can take the form of parallel multifilament strands compressingly encasing the core 78; or they can comprise twisted and plied filament strand yarns compressingly encasing the core.

The purpose of the opposed orientation of the overwraps 82 is to provide compression against the core 78 when the composite unit is subjected to tensile forces. It was stated relative to FIGS. 1, 2 and 3 that under applied tensile force, the organic fibers will elongate. Further, the overfeed of glass filaments will straighten out from the helical static overfed condition of the composite. When applied to the structure of FIG. 11, the glass strands 82, by being opposed and balanced against one another, will compress the resilient and bulky filaments 80 of the core, against one another in a compression spring type of action. The compression unit of this embodiment of the invention has extended durability because the cushioning and buffering effect of the elastic organic filaments combats abrasion and facilitates alignment of the glass filaments under tensile forces.

A SECOND SHOCK-ABSORBING YARN; MULTIPLE ORGANIC EMBODIMENT; FIGS. 12 AND 13

In this embodiment of the invention, two organic filaments of different stretch characteristics are combined with glass filaments, the latter having very limited stretch characteristics. This embodiment can be made in several ways: Thus, (1) strands of glass filaments and stretchable organic filaments can be twisted first; and then plied into a composite yarn; (2) combinations of the two types of filaments, grouped into a single strand can be twisted; and (3) two strands of one material such as nylon (organic) and one strand of glass filament with only the glass made slightly longer than the other two strands can be twisted together.

Accordingly, the structure of FIG. 13 could comprise a relatively extensible core yarn 84, as of polypropylene fibers. These have an exemplary stretch of about 30 percent. The core yarn 84 is overwrapped to a first degree with organic filaments 86 of lesser stretch. Exemplary filaments would be nylon having a stretch per se of about 20 percent.

The outer overwrap yarn 88 comprises glass filaments either per se or in combination with an organic to provide a selected, lesser stretch. This outer wrap 88 is applied at a greater rate of overfeed than the first degree overwrap 86 or at a third degree of overwrap.

The functionality of this embodiment of the invention is best illustrated by reference to the graph of FIG. 12. Upon application of initial tensile loading, the polypropylene core yarns 84, having the greatest degree of elongation, will begin to stretch. As the core stretches, now referring to FIG. 2, the overwraps 86 and 88 of lesser stretchability, will being to straighten out or uncoil. This will balance the tougher nylon (20 percent stretch) against the more elastic polypropylene (30 percent stretch) and slow down the stretch of the polypropylene by assuming part of the load. This in effect decelerates the stretch of the polypropylene fibers as the nylon overwrap takes over. Then the nylon will assume a more fully straightened configuration as illustrated in FIG. 3, by mental substitution for the straight glass filament 22 there shown. In this condition, both the polypropylene filaments and the glass 88 becomes overwrapped on the taut nylon 86, which however has not been permitted to reach its yield point, the foregoing actions having all taken place beneath the break point line of FIG. 12.

Now the polypropylene and nylon filaments are both loaded and the tensile force has been in effect cushioned.

With continued tensile force application, the glass overwrap 88 filaments next straighten out, as the polypropylene and nylon continue to stretch. This also forces the nylon to the outside as in FIG. 3. When the glass is generally straightened it and both of the organic filaments 84 and 86 will now have assumed the load, and the stretching will be decelerated to zero by the inextensible nature of the glass filaments 88. This is just short of the break point line in FIG. 12.

It is to be understood that the ultimate tensile of the composite strand will be engineered to exceed the maximum loading to be assumed. This will prevent breakage of the unit and thereby permit repeated flexing. Obvious use applications of this type of composite strand are in the reinforcement of rubber products such as radial plys in tires, V-belts, flat belts, tubular goods such as hoses, etc.

SUMMARY

By the present invention individual end use requirements of strength, elongation and elastic recovery can be tailor-made by variations in the type and size (dimension) of the core yarn used plus the geometry of the helical wind.

By the present invention, composite structures are provided wherein the shortcomings of the individual component parts are substantially eliminated. Thus glass fibers alone, though slightly elastic and dimensionally stable, have for many textile applications and the characteristics of being difficult to elongate. This characteristic, plus the high density (low bulk of glass fibers) places the "cushioning power" of all-glass yarns below that of other textile fibers.

The organic fibers that have been used in accordance with the present invention as core yarns, including cotton, rayon, nylon, polyester, polypropylene and Nomex (polyamide) have different characteristics. Their dimensional stability is of substantially lesser magnitude than glass. None is fully resilient. The wide differences between glass and organic fiber properties have been utilized to produce unexpected results in this invention. Thus the glass fibers provide stability and strength to the composite structures. The organics provide necessary bulk and cushioning power. These permit utilization of a higher percentage of the glass filament properties. The geometry of the combination yarns provides the necessary false modulus to glass yarns. This is an important factor in the glass-organic organic combinations. Thus the geometry of the helical wind effectively reduces the elastic stiffness of the glass. A false modulus is built into the glass just as the coil spring inparts a false modulus to steel.

The contribution of the glass to the combination yarn is added strength without commensurate increase in bulk. Accordingly, many functional applications are inherent in this type of glass/organic combination yarns.

By this combination, there are many regained application areas and market areas for the organics which have previously been lost. Thus polypropylene can enter for the first time markets where its extremely high elongation has kept it out. Nylon and polyester fibers, while of themselves improvements on cotton and rayon, are improved in turn by glass combination.

High-performance coated fabrics, rubber reinforcements, high-strength rope and towing hawsers, tapes and webbings both for civilian and military use are markets with prime potential.

In accordance with this invention fabrics can be made which are calculated exactingly for the desired stretchability in one or more directions. Fabrics can thus be used as tire cord materials in a tire which is engineered mathematically for exacting requirements in the dynamics of its operation.

Within the scope of the invention, organic filaments can be made of elastomeric material; and can be of staple length as well as continuous.

Further, within the scope of the invention, a relatively more extensible filament intertwisted with a relatively lesser extensible filament is to be encompassed.