Method Of Weaving On Water Jet Loom

Abstract

A method for weaving a warp and a weft on a water jet loom, wherein a desized interlaced yarn with the individual constituent filaments being randomly twisted and interlaced is used as the warp and an ordinary non-interlaced yarn is used as the weft, and the weaving is carried out while maintaining the coefficient of static friction of the warp against the weft in the wet state at not more than 0.6, and the water-insolubility of the warp and the weft at 30 to 90 percent.

Description

This invention relates to a novel method for weaving on a water jet loom.

The conventional machine for weaving a filament yarn to make a fabric includes shuttle looms which have been used widely from old and shuttleless looms which have been developed relatively recently. The sluttleless looms have attracted especial attention for their advantage of producing woven fabrics at high speed. The water jet loom, a kind of the shuttleless loom, is adapted to carry a yarn on a stream of water jetted out from a nozzle and pick it up. Since water is used, this loom is applied mainly to the weaving of hydrophobic fibers, and has attracted especial attention in the art because of their various superior performances. In a weaving operation using the water jet loom, it is generally considered necessary to employ a pre-weaving step in which a warp is twisted and sized in order to impart coherency to it, just as in an ordinary shuttle loom. The warp so treated is then subjected to an ordinary warping process, and woven on the loom. The pre-weaving step is intended to reduce the occurrence of fluff or yarn breakage at the time of weaving. When a fabric produced by the above method is dyed, it is necessary to non-size the size applied to the yarn in the sizing step by scouring, in order to obtain a uniform dyeing. However, with the above method, it is difficult to prevent the occurrence of injuries to the fibers in the twisting step, and the employment of the complicated preweaving process itself adds greatly to the cost of production. Furthermore, the size applied in the size step tends to be removed in the subsequent weaving step, which in turn causes a reduction in the quality of the resulting fabric. Therefore, the omission of the pre-weaving step would be very desirable since the various troubles ascribable to this step can be removed, and the cost of production can be reduced, and naturally, the step of removing sizes can be omitted and the scouring and dyeing step can be rationalized. Attempts have been made in the art to realize this by using an interlaced yarn as warp. By the interlaced yarn is meant a yarn obtained by applying fluid forces to a multifilament yarn to twist and interlace the individual filaments of the yarn randomly, thereby to impart coherency to the yarn. From the viewpoint of imparting coherency, interlacing between the filaments has equivalent operation and result to true twisting or sizing. The interlaced yarn itself is well known to those skilled in the art, and a method for its production is described, for example, in British Pat. specification No. 924,089. Since the interlaced yarn has sufficient coherency even when not twisted or sized, it will be possible to subject it directly to the warping process without the pre-weaving step, and then weave it on a loom. Surprisingly, however, we have found that when the interlaced yarn is woven on a water jet loom, non-uniformity in the density of the fabric occurs in the weft direction (the so-called tight weft phenomenon), and causes a marked reduction in the quality of the fabric.

An object of this invention is to provide a novel method for weaving on a water jet loom hereby density non-uniformity in the weft direction does not occur even when an interlaced yarn produced by an ordinary method is used as a warp yarn.

Another object of this invention is to provide a method for weaving on a water jet loom having high speed performances, wherein weaving can be carried out in the absence of the twisting and sizing steps and the desizing step can be omitted in deying to be carried out later on, thus leading to a markedly reduced cost of production.

According to the present invention, there is provided a method for weaving a warp and a weft on a water jet loom, wherein a non-sized interlaced yarn with the individual constituent filaments being randomly twisted and interlaced is used as the warp and an ordinary non-interlaced yarn is used as the weft, and the weaving is carried out while maintaining the co-efficient of static friction of the warp against the weft in the wet state at not more than 0.6, and the water-insolubility of the warp and the weft at 30 to 90 percent.

The method of this invention will be described below in greater detail. We have made extensive investigations into the casue of the density non-uniformity which occurs in the weft direction of the fabric when an interlaced yarn is woven on a water jet loom without being subjected to the pre-weaving process. This led to the discovery that since the weft is thrown by water in the picking process in the water jet loom and the weft and the warp are placed under the wet conditions, the finish on the surfaces of the filaments of the warp and the weft drop off, and the surface properties of the warp and the weft change remarkably; and that the frictional resistance between both yarns on their fiber surfaces becomes high and as a result, non-uniformity in the density of weft occurs.

Warps and wefts usually used in the conventional weaving processes have a water-insolubility of not more than 20 percent, and a coefficient of static friction of the warp to the weft in the wet state of 0.7 to 0.8. The "water-insolubility," as used herein, is the weight percent of an finish which remains unremoved when a filament having applied thereto an finish is immersed for 1 minute in water at 25.degree.C. The "coefficient of static friction of the warp to the weft in the wet state" is a value measured by the Roder method which is well known in the art. According to this measurement method, a number of wefts are uniformly attached in parallel to each other to the surface of a cylindrical holder to form a friction body, and one warp is hung on this friction body in a manner such that the warp intersects the wefts at right angles. The cylindrical holder is rotated to cause friction between the warp and the wefts, and the coefficient of friction between them is measured while maintaining both the warp and the wefts in the wet state. The speed of rotation of the cylindrical holder is varied, and the coefficient of friction corresponding to the respective speed of rotation is measured. The coefficient of static friction is the value of the coefficient of friction which is obtained when the speed of rotation is extrapolated to zero.

As previously stated, the conventional wefts and warps have relatively low water-insolubility values, and when subjected to a water jet loom, intersect each other in the wet state, which tends to cause the removal of the oil attached to the surface of the filaments, and a consequent rise in frictional resistance between them. Furthermore, by the influences of the removal of the finish on the surface of the filaments, the coefficient of friction of the warp to the weft in the wet condition is increased to a greater extent. If wefts and warps having such increased coefficient of friction are used, slippage during weaving becomes very poor, and as a result, non-uniformity in density occurs in the weft direction of the fabric.

On the basis of the above analysis, we have made extensive research and development work in an attempt to remove the non-uniformity in weft density which occurs when using an interlaced yarn, and to rationalize the scouring and dyeing process. Consequently, we have found that the above difficulties can be overcome be weaving wefts and warps of the specified surface properties on a water jet loom, and this led to the accomplishment of the present invention.

It is essential that in the method of this invention, a non-sized interlaced yarn be used as a warp and an ordinary non-interlaced yarn as a weft when weaving on a water jet loom. By the term "non-sized" is meant that a size such as polyvinyl alcohol or starch generally used to impart coherency to filaments is not applied. The interlaced yarn may be produced by any known methods. The use of a non-interlaced yarn as weft is a necessary condition. If an interlaced yarn were used also as the weft, the resulting fabric would have a defect called "flash."

It is also necessary that the coefficient of friction of the warp to the weft under the wet conditions should be not more than 0.6. If this coefficient exceeds 0.6, the weft undergoes frictional resistance when picked during weaving on a water jet loom, and it becomes impossible to arrange the wefts regularly at the predetermined positions. This results in the occurrence of the non-uniformity in weft density, and the results intended by the present invention cannot be obtained. The lower limit of the coefficient of friction is not particularly critical, but preferably, it is usually about 0.4.

If the water-insolubility of either the weft or the warp is less than 30 percent, the treating agent applied to the yarns is removed in great quantities by the action of water during weaving on a water jet and consequently, the frictional resistance between the wefts and the warps in the weaving process increases, leading to the occurrence of the non-uniformity in weft density. On the other hand, when the water-insolubility of the treating agent for the warp and the weft exceeds 90 percent or when the interlaced yarn as warp is sized, it is necessary to remove the treating agent in the scouring and dyeing process, and the omission of the scouring step becomes difficult.

Since the individual filaments of the warp used in the method of this invention are fully interlaced with each other, it is not necessary to size it prior to weaving. Furthermore, the frictional resistance between the warp and the weft is low, and the water-insolubility is more than 30 percent. Accordingly, there is a reduced proportion of the treating agent that is removed by the action of water. Thus, during weaving on a water jet loom, the frictional coefficient between the weft and the warp is maintained low, and the occurrence of the non-uniformity in the weft density of the fabric can be prevented. Furthermore, since the water-insolubility of the weft and warp is not more than 90 percent and the warp is not sized, no special step of removing the treating agent is required in the scouring and dyeing process, and it become possible to omit the scouring step.

The suitable warp and weft used in this invention are a multifilament yarn. Suitable filaments are polyester, polyamide, and polyacrylonitrile filaments. The number of the filaments or the total denier of the multifilament yarn is not particularly limited. Usually, however, multifilament yarns having a monofilament denier of 1 to 5 containing 12, to 48 monofilaments are preferred.

The specified water-insolubility and frictional coefficient values of the warp and the weft used in this invention can be realized by properly choosing the finish or other treating agent to be applied to the multifilament yarn. This choice is obvious to those skilled in the art.

There are various treating agents for the warp and weft to be used in the present invention. When the treating agent is applied during spinning, the treating agent should suitably contain 60 to 90 percent of a lubricant, preferably a synthetic lubricant, and it is preferred that the lubricant should be applied so as to cover the surfaces of the filaments. Suitable lubricants are, for example, trimethylol propane tridecanoate, isotridecyl stearate, oleyl oleate, isocetyl stearate, isostearyl stearate, and 2-ethyl hexyl palmitate. Although not a lubricant, wax and low molecular weight polyethylene are also effective for reducing the coefficient of static friction of the yarn in the wet state when used in a small amount. The amount of lubricant in the entire treating agent is preferably 60 to 90 percent by weight. The amount of the wax or low molecular weight polyethylene may be several percent. As is well known in the art, another ingredient such as an emulsifier or antistatic agent may be incorporated into the treating agent. It is preferred that the amount of the treating agent to be adhered to the yarn be 0.6 to 1.5 percent by weight as the total finish pick up, and 0.4 to 1.4 percent by weight as the amount of the lubricant adhered. The total finish pick up is measured by a method utilizing extraction with cyclohexane, and the amount of the lubricant adhered is calculated from the total finish pick up and the proportion of the lubricant based on the total amount of the treating agent.

The application of the treating agent to filaments is mainly performed during a yarn-making process involving spinning and drawing, and in the case of an interlaced yarn, the treating agent is applied before or after interlacing. The time of application, however, is not limited to this, and it is possible to apply the treating agent at any desired stage after drawing up to the weaving process.

The following Examples will illustrate the present invention. The non-uniformity of weft density and the degree of dyeing uneveneness used in the Examples were evaluated by the naked eye on a scale of grades 1 to 5 using 10 samples each having a length of 46 to 50 m, and average values were calculated.

Grade1: Not perceptible at all

Grade 2: Slightly perceptible

Grade 3: Perceptible to some extent

Grade 4: Considerably perceptible

Grade 5: Very considerably perceptible

EXAMPLE 1

In a process for obtaining a drawn yarn of poly-caproamide (70 denier/16 filaments) by an ordinary spinning and drawing method, an emulsion consisting of 50% of mineral oil (lubricant), 47% of an ethylene oxide added oleyl alcohol (emulsifier) and 3% of diethanol oleoamide (emulsifier having antistatic properties) was applied to the yarn to a total finish pick up of 1.0% during the take-up of the yarn (the water-insolubility of this yarn was 48%). Immediately after drawing, the yarn was interlaced by treating with turbulent fluids through a known nozzle to form an interlaced yarn. This interlaced yarn was supplied as a warp without sizing. As a weft, there was used a drawn yarn of polycapramide (70 denier/24 filaments) obtained by a usual spinning and drawing method wherein each of the various emulsions shown in Table 1 was applied to the filament during the take-up of the spun filaments. A plain weave taffeta was produced on a water jet loom using these warp and weft yarns.

Table 1 shows the composition of the emulsion used to produce the warp, the proportion of the lubricant in the emulsion, the coefficient of friction of the warp to the weft in the wet state (.mu..sub.w), the water-insolubility of the weft, the weft non-uniformity in weft density druing weaving on a water jet loom, and the dyeing unevenness of the fabric dyed without scouring. ##SPC1##

In Runs Nos. 1 and 5 which were performed in accordance with the method of this invention, there was hardly any non-uniformity in weft density and yarn uneveness of the fabric, and the resulting fabric had uniform good quality. In Run No. 2, the degree of density non-uniformity is high because of the low water-insolubility of the weft, and in Run No. 4, the degree of density non-uniformity of the fabric is high because of the high .mu..sub.w value. In Run No. 3, the water-insolubility of the weft is too high, dyeing uneveness occurs in the weft direction when the resulting fabric is dyed without scouring. Accordingly, such a fabric must be dyed after removing the finish, and it is impossible to rationalize the souring and dyeing process as intended by the present invention.

The degree of the density non-uniformity was evaluated by the naked eye. The actual state of the non-uniformity can be clearly observed by the accompanying phtographs designated FIGS. 1 and 2. FIG. 1 is a microscopic photograph of the fabric obtained in Run No. 1 which shows that the sizes of the warps and wefts and the distances between the wefts and between the warps are uniform. FIG. 2 is a microscopic photograph of the fabric obtained by the method of Run No. 4, which shows that the sizes of the warps and the distances between the warps are uniform, but the sizes of the wefts and the distances between the wefts are very non-uniform. The arrows in the figures show the warp direction.

EXAMPLE 2

In a process for obtaining a poly-caproamide drawn yarn (70 denier/16 filaments) by an ordinary spinning and drawing method, each of the various emulsions shown in Table 2 was applied to the filaments, and immediately after drawing, the yarn was interlaced using turbulent fluids through known nozzles. Without sizing, the resulting interlaced yarn was supplied as a warp. As a weft, there was used an ordinary drawn yarn of polty-caproamide (70 denier/24 filaments) wherein the emulsion used in Example 1 to produce the warp was applied to the yarn to an finish pick-up of 1% (the water-insolubility of the yarn was 46%). Using these warp and weft, weaving was performed on a water jet loom in the same way as in Example 1.

The treating conditions and the test results of the resulting fabrics are shown in Table 2 below. ##SPC2##

The results obtained are very similar to those obtained in Example 1.

EXAMPLE 3

Weaving on a water jet loom was performed using the combinations of warps and wefts shown in Table 3. The numbers indicated in the rows of the warp and weft show the number of the Runs in Examples 1 and 2. For example, in Run No. 11, the same yarn as used in Run No. 7 was used as the warp and the same yarn as used in Run No. 1 as the weft.

TABLE 3

Run Nos. 11 12 13 14 Warp No. 7 No. 8 No. 6 No. 6 Weft No. 1 No. 1 No. 2 No. 3 Coefficient of 0.35 0.34 0.32 0.31 friction (.mu..sub.w) Water-insolubi- lity (%) of the 25 96 66 66 warp Water-insolubi- lity (%) of the 65 65 22 95 weft Nonuniformity in weft density 4.5 1.0 5.0 1.0 (grade) Dyeing unevenness (grade) Warp 1.0 4.0 1.0 1.0 Weft 2.0 1.0 2.0 4.0

The results shown in Table 3 demonstrate that when the coefficient of friction (.mu..sub.w) is within the range specified in the present invention but the water-insolubility of either of the warp or the weft is too low or high, the intended results of the invention cannot be obtained.

EXAMPLE 4

In a process for producing a drawn yarn of polyethylene terephthalate (50 denier/24 filaments) by an ordinary spinning and drawing method, each of the various emulsions shown in Table 4 was applied to the filament during the take-up of the filament, and after drawing, the yarn was interlaced by turbulent fluids using a known nozzle. The resulting interlaced yarn was fed as a warp without sizing. As a weft, there was used a drawn yarn of polyethylene terephthalate (50 denier/24 filaments) obtained by an ordinary spinning and drawing method wherein the emulsion consisting of 50 % of mineral oil, 42% of an ethylene oxide added oleyl ether, 3% of dioctyl sulfosuccinate and 5% of oleic acid triethanol amine to produce the warp s applied to the yarn during the take-up of the spun filament to an finish pick-up of 1% (the water -insolubility of the yarn was 50%). Using these warp and weft, weaving on a water jet loom was performed.

The treating conditions and the test results of the resulting fabrics are shown in Table 4 below. ##SPC3##

The results obtained are similar to those obtained in Example 1.

Claims

What we claim is:

1. A method for weaving a warp and a weft on a water jet loom, wherein a non-sized interlaced yarn with the individual constituent filaments being randomly twisted and interlaced is used as the warp and an ordinary non-interlaced yarn is used as the weft, and the weaving is carried out while maintaining the coefficient of static friction of the warp against the weft in the wet state at not more than 0.6, and the water-insolubility of the warp and the weft at 30 to 90 percent.

2. The method of claim 1 wherein the warp and the weft are a multifilament yarn of a polyamide, polyester or polyacrylonitrile.

3. The method of claim 2 wherein the multifilament yarn has a monofilament denier of 1 to 5 and contains 12 to 48 monofilaments.