TUFTED PILE FABRIC

The present invention relates to the manufacture of tufted pile fabric and more particularly to the manufacture of tufted pile fabric wherein the fabric backing is a non-woven fibrous fabric containing a predominant proportion of heat- shrinkable synthetic thermoplastic textile fibers.

An object of the invention ia to provide a method of making s tufted pile fabric having a backing predominantly com¬ posed of non-woven heat-shrinkable synthetic thermoplastic fibers in which the fabric may be tufted at a wider width than the desired final width of the fabric, whereby large pile yarns may be used and the tufting apparatus may be one containing relatively larger needles or one having the needles set at a wid¬ er gauge, or both.

Another object of the invention is to provide a method for the manufabture of tufted pile fabric having such a backing which will produce cut pile fabrics wherein any objectionable "rowiness" of the pile face ia reduced or eliminated.

Another object is to provide a tufted pile fabric hav¬ ing such a backing structure in which any tendency of the com- pleted fabric to shrink widthwise when exposed to unduly high temperatures is reduced.

A further object is to provide such a process wherein a single tufting machine may be used for the manufacture of tuft¬ ed pile fabrics of two different widthwise gauges with the same single set of high-low pattern control attachments.

Other objects, features and advantages of the invention will become apparent from the following description of an illus¬ trative embodiment of the invention wherein reference is made to the accompanying drawing, in which; Pig. 1 is a plan view, somewhat schematic, illustrat¬ ing the process and showing apparatus on which the process may be practiced; Pig. 2 is a vertical sectional view taken on line 2-2 89684$ of Fig. 1 looking in the direction of the arrows; Pig. 3 is a perspective view of a tufted pile fabric having a backing of the type made use of in the invention; and.

Pig. l± is a similar perspective view of the fabric of Pig. 3 after it has been treated by the process of the in¬ vention.

In accordance with the invention we provide a method of making a tufted pile fabric, such as a pile fabric floor covering, employing a sheet backing fabric which comprises a needled sheet~like web of intermixed textile fibers in which the majority of the fibers are of a heat-shrinkable synthetic thermoplastic material, preferably polypropylene, the web being needled throughout its thickness at a multiplicity of closely spaced points distributed over its surface with fibers at dif¬ ferent levels of the web having portions which are displaced vertically relative to the thickness of the web at said points, the exposed fibers on at least one exterior surface of the web being bonded together, the needled web also including fibers located between the exterior surfaces thereof which are not bonded together and are mobile relative to each other, the backing fabric having a plurality of spaced pile yarns ex¬ tending therethrough at spaced points along each yarn to pro¬ vide a plurality of pile elements upstanding in rows from one face of the backing fabric, the yarns extending from the pile elements through the backing fabric and along its other face to adjacent pile elements, and the portions of said pile yarns passing through the backing fabric being resiliently gripped by the unbonded fibers of the backing fabric. The backing fabric is shrunk by continuously moving it in a direction lengthwise of the pile yarns through a heating zone, preferably a heating zone containing a heated atmosphere, to heat the shrinkable fibers to a temperature above the temperature at which they shrink but not to heat them above their fusion temperature for any appreciable length of time, while substan¬ tially inhibiting lengthwise shrinkage of the backing fabric by engaging the backing fabric along a line transverse to said lengthwise direction adjacent one side of said heating zone and feeding it toward the interior of said heating zone at a controlled rate of advance and again engaging said backing fabric along another line transverse to said lengthwise direc¬ tion adjacent to the opposite side of said heating zone and withdrawing the backing fabric from the interior of said zone at the same controlled rate, and controlling shrinkage of said backing fabric in the transverse direction by continuously en¬ gaging each side edge of said backing fabric and constraining each of said edges to move along a fixed line inclined toward the middle of said backing fabric as it travels in said heat¬ ing zone. Preferably the side edges of the fabric are en¬ gaged and constrained to remain at a constant distance apart during the final portion of the travel of the fabric within the heating zone.

Although the invention is not confined thereto, the backing fabric conveniently may be a backing fabric of the charac¬ ter disclosed in Parlin et al. United States Patent No. 3»39l4-><%3 issued July 23, 1968. Generally speaking, the backing fabric of United States Patent No. 3,39k»0l|-3 is comprised pfincipally of fibers of a thermoplastic material, such as polypropylene or other polyolefins having similar characteristics, including mixtures, which have been subjected to needling and with the fibers on at least one surface of the backing fabric being bonded together. The fibers employed may be those termed "waste" fibers in the trade. The fabric may be formed by dis- trlbuting the fibers by means of garnets in one or more super¬ imposed layers on a carrier such as a low-count cotton cheese¬ cloth. The cheesecloth with the fibers deposited thereon is then moved to a needling machine where the web is subjected to -3?* a needling operation which causes the fibers to be intimately intertwined and interengaged with each other throughout the thickness of the web, particularly at the points of needling, and causes fibers from different levels of the web to be inter¬ mixed in more intimate engagement with each other and imparts strength to the web. A closed barb needle of small diameter, such as a #32 fine felt triple barb needle may be employed for this purpose. Needling preferably is performed with the cheese¬ cloth adjacent to the lower face of the web so that the ends of some fibers are forced through the open mesh of the cheese¬ cloth. Thereafter when the surface fibers of this aide of the fabric are fused or bonded together they also engage with and grip the threads of the cheesecloth and thus prevent slippage or movement of the cheesecloth relative to the web of needled fibers. Under these conditions the fused fibers and the threads of the cheesecloth combine to resist and overcome the forces exerted on the backing fabric as a result of tufting and permit the desired dimensions to be maintained. When the fabric is tufted it is preferable that the cheesecloth or the like be adjacent to the upper or pile face of the fabric.

After needling, fibers on one or both exterior surfaces are bonded together to a flattened and hardened condition with the interior fibers remaining unbonded and mobile relative to each other. This may be done by heating the surface fibers to their melting temperature so as to fuse the surface fibers with¬ out fusing the fibers of the interior of the web. Such bonding may be accomplished with fibers of polypropylene having a melt¬ ing point between 310° and 320° P. by heating the surface fibers briefly to a temperature between 325° and 350° P. by oon- tact with rollers. When heated in this manner the fibers in the center or interior of the web do not reach their melting temper a tvire and will remain unbonded or unfused and mobile with respect to each other. Such bonding tends to increase the tensile strength of the web and reduce its elongation and the bonded or fused surface can pass beneath the needles of the tufting machines during the tufting operation without excessive interference or objectionable drag.

The backing may be made entirely from polypropylene fibers or from mixtures of polypropylene fibers with fibers of other materials such as nylon, rayon, acrylic resins, and polyesters, or mixtures thereof. A satisfactory backing or support fabric for tufted carpets may be made from polypropylene fibers of 3 to 1$ denier. Which are commonly produced com¬ mercially.

An example of a suitable mixture of fibers is a mix¬ ture containing 6%% of 6 denier crimped polypropylene fibers of lj.--l/2 in. staple length, 2$% of 3 denier crimped polypropy¬ lene fibers of 3 in. staple length and 10% of rayon fibers of 3 in. staple length.

The unbonded or unfuaed fibers in the interior of the backing retain their resilient characteristics and thus have a tendency to close on the portions of the pile yarns which extend through the backing fabric and to hold the pile yarns in place more effectively in the drawing of the loops than is the case with loosely woven backing fabric such as burlap.

Preferably the bats or mata of fibers issuing from the garnet are disposed transversely in the web of backing material formed from them, as in United States Patent No.

3»39l4.,OI4.3, so that the fibers are disposed predominantly trans¬ versely, i.e. widthwise, of the web. It is generally desir¬ able to deposit more than one layer of the mat issuing from the garnet on to the cheesecloth, or other carrier, so as to obtain a more even and uniform distribution of the fibers in the backing fabric.

In lieu of cheesecloth, we may employ a layer of longitudinally extending polyester filaments, threads or yarns, or a layer of an oriented synthetic polymer film, preferably a polypropylene film, which is fibrillated by the needling operation.

The pile elements are formed on the backing in an entirely conventional manner by the use of the usual tufting machines employing a gang of reciprocating needles, as is well known in the art.

An illustrative process in accordance with the inven- tion will now be described. Referring to the drawing, a tuft¬ ed pile fabric floor covering 2 having pile tufts 3 and a non- wovein backing i; of the character heretofore described is supplied from a supply roll 6. The roll 6 is provided with pins or spikes . T Which prevent slippage of the backing k on the roll and the roll 6 is driven in any suitable manner at a controllable speed. The roll 6 thus serves to engage the backing along a transverse line and release the fabric 2 at a controlled rate.

The tufted pile fabric 2 moves forwardly in the direction of the arrow 8 over a guide roll 10. The opposite edges of the fabric are engaged by a pair of tenter chains 12, II4.. The tenter chains 12, II4. carry upstanding pins 16 and at their front ends pass about guide rolls 18, 20 respectively so that their inner flights move beneath the edges of the fabric 2, as shown, in position to engage the edges on the pins 16. Two rotary brushes 22, 2I4. engage the upper or pile face of the fabric 2 above thé pins as shown and press the edges downward¬ ly to engage the edges of the fabric on the pins 16, as shown to beat advantage in Fig. 2.

Upon leaving the brushes 22, 21+ the fabric 2, with its edges engaged with the tenter chains 12, 11+, enters a heating zone in a heating chamber 26. The heating chamber 26 contains air heated to the appropriate temperature by steam circulating coils 28. In the case of a tufted fabric having a backing which is compoaed predominantly of polypropylene fibers as in United States Patent No, 3,39I4.» 0i|.3, the temperature in the heating chamber 26 is maintained in the range 3l5o-3200 p„ Adjacent the entrance to the heating chamber 26 the inner faces of the tenter chains 12, II4. pass over guide rolls 32, 31+ which serve to suitably space the tenter chains in their extent from the rollers 18, 20 to the guide rolls 32, 314.0 Ordi¬ narily this spacing will be such that the fabric 2 as it is engaged and held by the pins 16 is maintained at its initial width. Thereafter the outer faces of the tenter chains 12p 11).

pass over the guide rolls 36, 38 which are spaced more closely together than the guide rolls 32, 3U- 3° tka* the tenter chains and the edges of the fabric 2 engaged by them are constrained to move along a fixed line inclined toward the middle of the backing fabric. As the fabric 2 moves into the heating zone in the heating chamber 26 its temperature ia raised and as the temperature of the shrinkable fibers in the backing reach their shrinking temperature the fabric shrinks. Aa the fabric shrinks, the inclined portions of the tenter chains between guide rolls 32, 3I4. and guide rolls 36, 38 control the shrinkage ..go that it is uniform and of the desired amount.

As the tenter chains leave the guide roll pair 36, 38 they pass to the guide rolls l+O 12 engaging their outer surfaces and about which they pass so that their return flights kk-* k£> a1*6 passed about the guide rolls t<.8s $0 and $2, $1 to return to the guide rolls 18, 20, respectively. The guide rolls of the pair 14.0, I4.2 are spaced apart the same distance as the guide rolls 36, 38 so that the side edges of the fabric 2 are main¬ tained a constant distance apart, corresponding to the shrunken width of the fabric, during the final portion of the travel of the fabric within the heating zone.

Adjacent the exit side of the heating zone the fabric 2 is engaged along another transverse line by a spike roll 56 which is driven in any suitable manner at the same rate as the roll 6 to withdraw the fabric 2 from the heating zone at the same speed as it ia released from the roll 6 so as substantial¬ ly to inhibit lengthwise shrinkage of the backing fabric. When the shrinkable fibers in the backing 2 are disposed predominant- ly in the transverse direction, this disposition of the fibers aids in confining the shrinkage of the fabric to a widthwise shrinkage. Also, when the backing contains longitudinally ex¬ tending polyester strands, which do not shrink at the tempera- tures which are sufficient to adequately shrink the backing made predominantly of polypropylene fibers, this arrangement also aids in confining shrinkage to the widthwise direction.

The fabric 2 issuing from the heating chamber 26 ia lifted from the pina 16 of the tenter chains at 58 and ia finally wound up on any suitable take-up arrangement such as the take-up roll 6'0.

Pig. 3 illustrates the tufted pile fabric 2 in the condition in which it enters the apparatus of Figs. 1 and 2.

The pile yarns form the pile element 3 upstanding from one face of the backing 1+ with the yarn extending from the pile éléments through the backing I4. and along the lower face of the backing at 62 to connect with adjoining pile elements. In this embodiment the backing does not contain a cheesecloth layer but Instead contains a layer of polyester threads or yarns 6lj., bonded to the superficial polypropylene fibers at the front or upper face of the tufted fabric. Such arrangement aids in eon- fining shrinkage to the transverse direction, which is cross¬ wise of the strands 64..

The tufted pile fabric in the condition in which it issues from the apparatus of Figs* 1 and 2 ia shown in Fig. k* Here the backing ia narrower than in Fig. 3. We have found that a tufted pile fabric floor covering may very conveniently be reduced in width by 20$6, that is reduced from a standard foot width to a width of 12 feet, when the backing is compoaed of polypropylene fibers, if the temperature in the heating chamber 26 is maintained in the range 315°-320° F,, the length of the chamber is approximately 21 feet, the distance between the roll pair 32, 31]. and the roll pair 36, 38 is approximately 13 feet, and the distance from the roll pair 36, 38 to the- exit end of the chamber is approximately 8 feet, and the speed of the fabric through the heating chamber 26 is approximately case, the roll pairs 32, 3£j. and 36, 38 are adjusted so that the spacing between the tenter chains 12, 11+ decreases by 20$ in passing from one roll pair to the other» We have found that when applied to cut pile tufted fabrics, our process provides a completed fabric in which the objectionable "rowiness" often associated with cut pile in tufted carpet is greatly reduced or entirely eliminated. We think this may be due to the legs of the cut tufts turning as the fabric shrinks and compresses adjacent cut legs against one another so that the objectionable visual effect due to some of the tufts being "J" tufts and others not is greatly reduced.

In any case, whatever the explanation may be, we have found that cut pile tufted fabrics, even those having a pronounced degree of "rowiness", have this defect either materially re¬ duced or entirely eliminated when treated by the process of the invention.

.9.

Ths embodiments of the invention in which an exclusive