JPS5920018B2 - polypropylene non-woven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an improved non-woven carpet packing for use in making tufted pile carpets.

A nonwoven web of oriented polypropylene continuous filaments is described in Edwards, US Pat. No. 3'563,838.

Edwards' nonwoven webs have high resistance to tearing in the machine (length of the fabric) direction, high resistance to elongation in the machine direction, and neckdown in the cross direction when stressed in the length direction.
) is useful for the manufacture of carpets that simultaneously have a high resistance to

The orientation specified in the Edwards patent is also responsible for providing high resistance to diagonal deformation.

Edwards type carpet backings can be prepared and bonded by many methods.

Herrman U.S. Patent No. 3
No. 546062 describes the preparation of sheets consisting of randomly distributed filaments;
In this case, the binder in the sheet is derived from segments that are less drawn than the segments in the other filaments.

These less drawn segments have a lower melting point than the highly drawn segments and act as a binder to the nonwoven web when the web is heated.

The Hellman patent also encompasses the use of filament mixtures in which some filaments are highly drawn and other filaments are relatively lightly drawn.

It is a well-established practice in the tufting industry to apply synthetic or natural rubber latex to the back side of tufted carpets to provide a positive anchoring effect for the pile yarns in the carpet backing.

It has been found that latex tends to reduce tear strength.

For example, comparing the experimental data described in Examples ■ and X■ of the above-mentioned U.S. Pat. It has been known.

It is an object of the present invention to produce a highly latex-free tufted tongue at moderate neckdown levels.
) To provide a nonwoven polypropylene carpet backing that has tear strength and retains most of its tear strength even after tufting and latex application.

The present invention consists of a layer oriented along the length of the fabric providing one surface of the fabric and a layer oriented perpendicular to the length of the fabric, each layer comprising a binder filament and a matrix, respectively. filaments, the matrix filaments having a tenacity of at least 2.5 S'/denier, an isotactic polypropylene non-woven fabric consisting of layers of bonded continuous filaments, each layer having a tenacity of at least 2.5 S'/denier; 40-60%, the matrix filaments have an average denier of at least 12, each layer contains 18-50% by weight of binder filaments, and the layers oriented along the length of the fabric have an average denier of at least 12. .0
The layer has an MDL/XDL value of at least 3.0 and is oriented perpendicular to the length of the fabric.
L/MDL value, where XDL is the measure of the total filament length in the direction perpendicular to the length of the fabric in the layer in question and MDL is the measure of the length of the fabric in the layer in question. (which is a measure of the total filament length in the direction of -= 3.5 to 30 45° (However, in the above formula, XD is a measure of the total filament length of the entire filter cloth in the direction perpendicular to the length direction of the cloth, and MD is the measure of the total filament length in the direction of the length of the cloth. 45° is a measure of the total filament length of the entire fabric, and 45° is the two directions of ±45° with respect to the length direction of the fabric (herein, the two directions of ±45° are:
(meaning the two directions intersecting at an angle of 45° at the right diagonal and the left diagonal with respect to the direction of the length of the fabric), where XDL, MDL, MD , XD and 45[deg.] as measured by the randomometer method.

The amount of binder filaments in the layer oriented in the length direction of the fabric (this direction is sometimes referred to as the machine direction) is
It is preferred that the amount of binder filaments in the layer be at least 1.2 times the amount of binder filaments oriented in a direction perpendicular to the length of the fabric (sometimes referred to as the transverse machine direction).

This cloth has a layer oriented along the length of the cloth on one surface.
It is also preferred to have a layer on the other surface that is oriented perpendicular to the length of the fabric.

The binder filaments have a lower orientation than the matrix filaments, as will be explained in more detail below.

The binder filaments may be separate from the 7-trix filaments or may be present as segments alternating with matrix segments in the fabric filaments.

The product of the invention is a bonded nonwoven fibrous sheet consisting of two or more layers having different average filament orientations.

This is Edwards' United States fi = 356
No. 3,838 and conceptually illustrated in FIG. 5 of that patent;
One layer, the bottom layer, consists primarily of filaments whose main directional component is oriented in the machine direction of the sheet, while another layer, the top layer, consists primarily of filaments whose main directional component is oriented in the machine direction of the fabric. It consists of filaments that intersect with each other.

The relative lengths of filaments oriented in different directions in each layer can be measured by use of the random meter method described in the Edwards patent.

A layer of the sheet consisting primarily of filaments in which the predominant directional component is transverse to the machine direction of the length of the fabric is designated herein as an The layer in the machine direction of length is named the M layer.

In FIG. 1, layer 2 consists of filaments with the majority of the directional component in the machine direction and is referred to as the M layer.

Layer 1 consists of filaments with the majority of the directional components located intersecting the machine direction, and this layer is referred to as the X layer.

For convenience of explanation, each layer may be designated by a series of letters representing the laydown order, with the first letter indicating the bottom layer of the sheet.

Since the sheet can later be observed from either side, only the relative placement of each layer is important in characterizing the product.

Using this method of description, for example, XM indicates first laying down the X layer on the moving belt and then depositing the M layer on top of the X layer.

The array sheet labeled MX also has a machine direction layer deposited first and an X layer deposited second.

Of course, a single M or X layer can be deposited by using multiple jets across the width of the accumulating belt.

Additionally, several banks of jets can be used in succession.

If successive banks of jets deposit filaments in the same general direction, the accumulated material can be considered a single layer.

MXM aligned sheets are manufactured by sequentially depositing a machine direction layer, a cross machine direction layer, and another machine direction layer.

As mentioned above, it is common practice to apply latex to the backing of carpet material after it has been tufted.

Generally, enough latex is applied to penetrate approximately half the thickness of the backing.

It is important that the latex-containing part is in the machine direction because this layer has an appreciable tear strength in the machine direction (which is one of the most important properties in carpet manufacturing). This is because the tear strength is reduced by coating the latex.

In contrast, fibers aligned in the cross-machine direction should be kept free of latex as much as possible.

For this reason, the M layer must provide one surface of the fabric, while the It must form the main component of half of the

The bonded nonwoven sheets of the present invention provide carpet manufacturers with high MD tufts before and after latex application, even though they can be manufactured as low weight and therefore more economical than conventional sheets. To provide a carpet backing that can be tufted to provide a carpet with tongue tear strength.

For example, 101.5 of the present invention? /I (3 oz/sq yd) sheet with 1% neck down and 25 kg (55 lb) of unlatexed M
A tufted carpet having a D tufted tongue tear strength and a latex coated MD tufted tongue tear strength that is at least 70% of the unlatexed tufted tongue tear strength at a latex penetration of about 50%.

A method similar to that of the present invention is described in the aforementioned Edwards patent.

Referring to FIG. 2, a ribbon 3 of filaments is obtained by extruding filaments 4 from a spinneret 5, cooling them and passing them over guides 6.

The ribbon of parallel filaments is successively rolled 7.8, 9,
10° Passes over 11 and 12.

The yarn moves with progressively increasing speed in each successive roll.

A significant speed increase can occur between rolls 8 and 90, and typically between rolls 10 and 11, thereby providing increased molecular orientation (stretching).

Stretching can be aided by heating the filament or a portion thereof in rolls 8 and 10.

Since roll 8 is a smooth cylindrical roll, uniform stretching is achieved between rolls 8 and 9.

However, the roll 10 is a grooved roll, having grooves running along its surface in the axial direction.

Segments of yarn that contact the heated surface of the roll between the grooves undergo additional stretching, while segments floating above the grooved portions do not undergo additional stretching.

The resulting filament 13 has highly oriented and relatively less oriented segments alternating along its length.

The filament then passes into a slot jet 14 of the type shown in FIG. 6 of the Edwards patent.

The ribbon 13 of filament passes around a convex roll 300, which increases the width of the ribbon, and then the filament is passed around a convex roll 300, which increases the width of the ribbon, and then the filament is
) imparts an electrostatic charge as it passes across the target bar of a corona discharge device 15, such as that described in U.S. Pat. No. 3,163,753.

A ribbon of electrostatically charged continuous filaments is drawn into the mouth of the slot jet 14 and deposited on a belt 35 moving in the direction shown as it exits the slot jet outlet 17.

The width of the descending ribbon is in the cross machine direction.

At the exit of the jet, the moving ribbon of filaments is deflected by alternately applying pulses of air from one side of the ribbon, then the other, to create a swath of filaments aligned primarily in the machine direction. )
cause

- or more products from additional spinnerets are treated similarly, but are deposited primarily with alignment in the cross-machine direction.

Optionally, the filament ribbon 13 is partially treated as described above and partially passed over a buffer pin 19 on a convex roll 31 into a corona discharge means 32 and against the jet 14. It can be separated to pass through slot jets 20 arranged at right angles.

Applying alternating air pulses to the filaments 21 exiting the slot jet 20 provides a swath with filaments oriented primarily in the cross-machine direction.

In FIG. 3, the filaments 50 extruded from the spinneret 51 are separated into two streams.

On the one hand, roll 54 .
55 and 57 for depositing onto the moving belt 60 via charging means consisting of a multi-point electrode 73 and a grounded cylindrical electrode 74.
Proceed to 9th grade.

Another group of filaments exiting the spinneret pass around guide rolls 61 and 620 and over rolls 63 and 64 to roll 54, where their flow is combined with the first group of filaments as a single group. continue.

Rows 77 of filaments aligned primarily in the machine direction are deposited.

A similar arrangement of equipment upstream with slot jets at right angles to slot jets 59 is used to provide a layer with filaments 78 primarily in the cross direction.

The filament is manufactured by W. as described in Jung U.S. Pat.
U.S. Patent No. 3313002 for ye th
Preferably, the bonding is carried out by passage in saturated steam using a bonding device of the type mentioned in the above.

Finishing agents are used to avoid excessive fiber cutting during tufting.

The finishing agent is Junk's US Patent No. 33226.
Polysiloxanes such as those described in No. 07 are preferred.

Excessive shrinkage can be avoided by confining the sheets by bonding.

The degree of bonding affects the properties of the nonwoven product.

As the bonding temperature increases, the neckdown of the tufted substrate decreases to a minimum value.

At the same time, increasing the bonding temperature causes the value of the tufted tongue tear strength to decrease again after passing through a maximum value.

A combination of tackdown and tufted tongue tear strength is needed for carpet butting.

Desirable products have a neckdown of 5 to 0.1%, although the exact value will vary depending on the intended use.

Test Method Orientation In each example, measurements are made for the orientation of the filaments in each layer of the bonded sheet.

These measurements were made in Edwards' U.S. Pat.
The method is similar to that described in column 9, lines 43-54 of No. 563,838.

After separating the bonded sheets into layers in the , the results are averaged (i.e., a weighted average proportional to the weight is performed).

For example, □ is the total filament length in the 45° cross-machine direction in the bonded sheet divided by the average of the total filament lengths in the 45° direction to the length direction.

The D term is the total 45° filament length in the bonded sheet in the machine direction divided by the average of the total filament lengths in the 45° direction to the length direction.

It should be understood that in these terms, 45° is not a divisor, but merely a symbol for the filament length in a direction of 45° to the length direction.

Additional details regarding the measurement of directionality, and factors including the use of randomizers for measurement, are described in the Edwards patent.

Furthermore, XDL and MDL measurements are performed for each layer.

XDL is the value of the total filament length in the layer in the direction perpendicular to the length of the fabric, and MDL is the value of the total filament length in the layer in the direction of the length of the fabric. It is a value.

Tufted tongue tear strength The machine direction tufted tongue tear strength of a tufted nonwoven fabric can be measured as follows.

The bonded nonwoven MX fabric is lubricated with about 2% polymethylhydrogensiloxane by weight.

A sample of lubricated sheet is cut along its length (in the machine direction) to form a 20.3 Crn (8 inch) wide strip.

This strip is attached to a tufting machine so that the needle enters the sheet from the M-array side and leaves a tuft on the X-array side of the sheet.

The tufting machine has needles with a spacing of 4.77 mm (0.188 inches).

Fabric in machine direction: 2.76 tufts/CIrL (7 tufts/CIrL) using 3700 denier Ken crimped continuous filament yarn over a 15.2 cm, (6 inch) width.
0.438 cm (0.4 cm), leaving 2.54 CII'L (1 inch) of untufted sheet on each side of the tufted area.
, 438 inches).

Cut a tufted substrate with 2.54crIL (1 inch) ears on each side to length (machine direction)
Prepare a 20.3 cr/L (8 inch) sample.

For the measurement of tufted tear strength, prepared 20
．． 3cIrLX 20.3cm (8 inches x 8 inches)
A machine direction cut is made in the sample starting from the center of one end and proceeding 10.2 crIL (4 inches) in the machine (tufting) direction.

The sample is attached to an Instron tear tester using a 3.8° x 5.1 cIrL (1.5 inch x 2 inch) serrated clamp.

The grip spacing is 7.6CrIL (3 inches), one side of the cut part is attached to the upper grip, and the other side of the cut part is attached to the lower grip,
A 180° change in direction is applied to the sheet at the tear point.

The width of the sample should be uniform between both grips.

Adjust the full scale load to a value greater than the expected tear strength for the sample.

Crosshead speed of 30.5 crfL/min (12 in/min) and 25.4 crfL/min (10 in/min)
Using a chart speed of , the tensile tester is started and the movement of the crosshead causes the sample to tear.

Measure stress in the usual way.

The three highest stresses during tear (100 units = full scale deflection) are averaged for each specimen.

If it is not possible to obtain three peaks, take the average of the obtained peaks.

Tongue tear strength in ky (or pounds) is the average stress divided by 100 multiplied by the full scale load in kg (or pounds).

Latex Coated Tongue Tear Strength Latex Coated Tank Tear is a measure of the ability of a finished carpet to withstand tear forces after latex coating.

3 parts Unirogil 3912 latex (solids content 70.
4%) and one part of Unileugil 3911 latex (
A latex consisting of 71.0% solids is prepared.

The 3912 product contains 60 solid elastomer particles.
It is an aqueous dispersion consisting of % styrene and 40% butadiene by weight.

The 3911 product is a similar aqueous dispersion except that the solid elastomer particles consist of 40% by weight styrene and 60% by weight butadiene.

An amount of mixed latex corresponding to 10 times the weight of the carpet backing in the sample is applied to the back side of the tufted carpet.

Rollers of different weights are used to evenly spread the latex depending on the degree of latex penetration required.

Several samples are tested, varying the amount of latex penetration in each sample.

The degree of penetration depends on the weight of the roller as well as the viscosity of the latex.

After drying and curing at 125°C, the degree of penetration is determined for each sample as follows: (1) Area A
Weight of unlatex treated sample excluding tufts (Wl)
(2) Peel off and remove all the fibers that have not been penetrated (wetted) by the latex in the same area of the sample excluding the latex-coated tact;
The weight W2 is measured, and the permeation percentage P1 is determined by equation (3) P=-X100.

A more approximate method of determining percent penetration is to peel back the sample and observe the approximate depth of the sheet material that has not undergone penetration.

Latex poultice samples prepared with different amounts of latex are tongue tear tested by the same method as the untreated latex samples.

Latex treated tongue tear values at 50% penetration can be obtained by indentation of the results on samples with several levels of penetration percentage P.

The primary carpet packing for the production of neck-down percent tufted carpets needs to be capable of reducing width in stretch, coupled with high tear strength.

During processing in a carpet-making machine, the tufted-subcarpet backing is subjected to significant longitudinal stresses, which not only lengthen the carpet in the machine direction, but also lengthen the tufted carpet in the cross-machine direction. This can cause a reduction in the width of the backing, or negging down.

Such dimensional changes are highly undesirable: unless corrected, such dimensional changes will cause changes in the tufting pattern of the carpet and will result in tufts having widths narrower than commercially acceptable. There is a risk of giving a teddy carpet.

The neckdown of a bonded and tufted nonwoven carpet backing can be measured as follows: The bonded nonwoven is tufted and cut along the rows of tufting as for the tufted tongue tear test. A sample with a width of 14.0 crrL (5.5 inches) and a length of 35.6 cR (14 inches) is prepared by doing this.

This sample was placed 10.2 (4,0 inches) and 20.3 cm (8,0 inches) from one end and 5
1c1'Il (2,0 inches) is marked by a line across the width direction and parallel to the end.

0.5 crIL (0.19 in.) from both grades of the sample against the sheet across the 20.3 c7'rL (8.0 in.) line.
Attach a metal stable to the finch.

Measure and record the spacing between the stables to the nearest 0.0254 cm (0.01 inch).

The sample is mounted on an Instron tester with a clamp spacing of 20.3 cr/L (8 inches).

Clamp is 10.2 crrL on the sample and 5. lCr
Attach the sample to a 2.54 Cr/'L (1 inch) x 20.3 cTL (8 inch) Instron clamp so that it is tangent to the l1 line and the sample is centered on the clamp.

The sample was then loaded using a full scale load of 22.7 to 9 (50 lb), a crosshead speed of 25.4 m (10 in) per minute, and a chart speed of 50.8 cm (20 in) per minute. Stretch in a testing machine.

The Instron is adjusted to stop when the load reaches 8.2 ky (18 lb).

This corresponds to 0.59 kg (3.3 pounds per inch) per ICIrL width of the sample.

When the Instron stopped, the distance between the stables was changed to 0.0254c1rL (0,0
Measure accurately to the nearest 1 inch.

The percent neckdown is equal to the difference between the initial inter-stable spacing and the inter-stable spacing under load divided by the initial inter-stable spacing multiplied by 100.

The fiber-strengthened matrix filaments are fluffed from the bonding sheet, separated, and placed in the grips of a tensile testing machine, such as an Instron.

The sample is stretched between grips spaced 1 inch apart at a rate of 2 inches/minute.

Cutting strength is defined as the load in duram units when the fiber is cut.

Convert cut strength to force in grams/denier by dividing the average cut strength by the average matrix denier per filament (see below).

Binder strength and the proportion of binder fibers or segments in the fibers comprised of matrix fiber denier segments are important issues.

The binder content is such that the matrix fibers have not undergone any significant stretching and therefore have a lower orientation and softening point than the matrix fibers.

The concentration of the binder content can be easily adjusted in the above method by changing the ratio of grooves to surface area in the grooved rolls or by increasing the proportion of filaments that bypass some or all of the drawing rolls. .

In either case, the binder content of the bonded wipe can be easily determined by the process of its manufacture.

Because the binder fibers or segments in the fiber have a low degree of molecular orientation (low birefringence), their color under crossed polarizing lenses is different from the color of the matrix fibers, which have a high degree of molecular orientation. color-based identification is thus possible.

The orientation difference is increased by bonding where high temperatures destroy the microstructure and reduce birefringence.

This deorientation is greatest when the initial molecular orientation is small.

In such cases, the molecular chains in the binder segments become severely disoriented, giving fibers that are gray or yellow-white when viewed under crossed polarized lenses, whereas the matrix fibers become dark under the same conditions. give color.

Fiber thickness can also be used as a binder identification characteristic, since in sheets prepared from segmented-drawn filaments, the binder diameter is more than 7 tricx diameter.

In sheets with relatively few significant differences in molecular orientation, birefringence measurements can be used to determine which fibers are the binder and which are the matrix.

To measure binder percent, a thin transverse section of the weighed basis weight is prepared and the length and diameter of all binder fibers within a predetermined area of this section are measured by the use of a projection microscope and polarized light.

The diameter of the matrix fibers is also measured.

From these measurements, the weight percent of the binder can be calculated using the fiber specific gravity and cylindrical geometry.

Since the binder % is required for each directionally aligned layer,
The bonded sheet is peeled into its component M and X layers.

In thick sheets, these layers must be further peeled away to make all the fibers visible to the naked eye.

For good visibility, each layer should be thinner than about 67.6 g/m'' (2 oz/sq yd) based weight.

Preparation of thin sections using a microtome can also be employed.

Measure the weight per square area of the component M and X layers.

The specimen is then placed on a microscope slide and immersed in oil with a refractive index of approximately 1.5.

An image of the specimen is projected onto a screen using a projector or similar microscope using polarized light transmitted through the sample and using a magnification of about 60X.

Tracing is performed on the pinda segment I. by using a transparent overlay with both polarizing and resolving filters set at 90° with respect to each other.

Then rotate both fins 2 times until the full rotation is 90°.
Rotate simultaneously at degrees of 0 to 25 degrees.

At each step, trace any additional binder segments in view.

A new field of view is then selected and the process repeated until the appropriate total area has been scanned.

Next, measure the length of the binder using a diagram reader.

This length divided by the magnification is the actual length of the binder in the scanned area.

By using a graduated eyepiece, the diameter of the binder filament between the bond points where the deformation is the least can be easily measured.

The diameter of the matrix filament can also be measured in a similar manner.

Needless to say, the measured values are corrected by the magnification.

Percentage of binder by weight in that layer of the sheet Q
is calculated from equation (1): πD2bLρ Q = -X 100 (1) AB where L - the actual length of the binder in the scanned area c
m) Length measured by overlay 7 magnification A - scanning area, crA = overlay area/(magnification) 2 Db - diameter of binder, ρ - specific gravity of woven fiber, ? /i (0.9P/i for polypropylene) B-
If the X and M layers are so thick that it is necessary to cleave each layer into several sublayers, the binder percentage is Obtain the value for the X or M layer by determining for the sublayers and then averaging the results for the sublayers.

The denier per filament dm of the matrix filament is calculated from formula (2): 4゜-・D'',,l・ (2) where Dm - the diameter of the matrix filament, dm - the standard length for the measurement of the denier. Sa,bo(9×105CIIL) Equation (2) can be simplified as Equation (3) by applying the corresponding value for π and giving a specific gravity of 0,9/ant for polypropylene. can.

dm = 6.36 x 10'D2 (3) Example 1 Composed of continuous fibers of isotactic polypropylene °C
A single nonwoven web is used with three rows of jets at the upstream end of the belt for cross-machine direction deflection and three rows of jets at the downstream end of the belt for cross-machine direction deflection. 3.2 using an arrangement similar to that shown in FIG. 5 of Edwards U.S. Pat. No. 3,563,838, except that
P/10 min (ASTM Method DI238, Condition L).

The spacing between the jets and their height above the collecting surface was such that the products from adjacent jets did not significantly overlap, but just barely touched on the collecting surface.

Polypropylene filaments were extruded through 6 spinnerets at a temperature of 250°C, each with a diameter of 0.38 m with a throughput of 0.705 P/min/hole.
It had 300 holes with a size of m (0,015 inches).

After the filament bundle from each spinneret was formed into a ribbon of parallel filaments, each ribbon was arranged as shown in FIG.

The film was drawn segmentally by passing it sequentially over six rolls (each having a circumference of 61.0 m (24 inches)) rotating at gradually increasing speeds from roll 7 to roll 12.

Rolls 8 and 10 are at 130 and 140°C, respectively.
The other rolls were not heated.

By providing grooves in the axial direction on the surface of the roll 100, the filament was prevented from being heated over a short length of the circumference.

The remainder of the circumference provided heat to cause the filament section to stretch as it passed over the heated surface.

The segmentally drawn continuous filament ribbon 13 thus produced was electrostatically charged by passing it across the target bar of a corona discharge device.

Each ribbon of charged continuous filament was then fed into a single slot jet of the type shown in Figure 6 of the Edwards patent.

The primary airflow spacing, designated 4 in the Edwards patent, is 2.92 mm (0.115 inches) wide and 24 in other dimensions.
．． It was ICTL (9.5 inches).

The oscillating plenum air spacing specified as 6 in the jet described in the Edwards patent was approximately 0.203 to 0.2 measured from one parallel side to the other.
It was 54 mm (0,008 to 0,000 inches).

This achieves high secondary airflow velocities without increased airflow, thus allowing a high degree of deflection without causing disjoint filament separation and preserving web uniformity during deposition. .

The air velocity is 10 to 1 of the primary air flow velocity in the jet.
．． It was twice that amount.

The nonwoven web deposited by the six jets was collected on a suction receiver.

4 webs A with a width of 76.3 cr/L (30 inches).

B, C and D were manufactured using the method described above; further details about this method, such as roll slot dimensions, speeds, etc., are shown in Table 1.

The accumulating belt speed was adjusted to accumulate sheets with a basis weight of 101.51/m (3 oz/sq yd).

Conditions for obtaining the optimum balance of properties were determined by bonding several samples of the sheet in saturated steam at several different temperatures.

After bonding, each sample was lubricated and then tufted into the MD oriented side in preparation for measurements of tufted tongue tear strength and percent neckdown.

In each case, the bonded samples were analyzed by selecting specimens along and across the web.

Values from several specimens along and across the sheet were averaged to obtain the basis weight, percent neck down, and tufted tongue tear strength.

In addition, fiber orientation was measured for each of the two layers (ie, X and M).

The values for the various sheets are summarized in Table 2.

Latex coated tongue tear values were also measured at approximately 50% penetration.

Matrix fiber denier, fiber break strength and binder percent for the X and M layers were measured for - versus - in the bonded sheet for each set for operating conditions.

It is assumed that each bound sample contains the same amount of binder under comparable operating conditions.

In Table 2, the values for sheets A, B, and D represent the characteristics of the sheet of the invention, whereas sheet C represents a sheet outside the invention.

It should be noted that sheet C has poor directionality in the M layer.

Each sheet had 50% by weight in the X layer and 50% by weight in the M layer.

Example 2 A 2.5P/1 (ASTM method DI2
Three nonwoven webs of continuous filaments of isotactic polypropylene were prepared from a polymer having a melt flow rate of 38, condition L).

The polypropylene filaments were extruded at 270°C through three spinnerets having 800 holes, each sized 0.020 inches in diameter, with a throughput of 0.56 rpm/hole.

The filament was drawn on a continuous roll as described in Example 1, except that only roll 10, the grooved roll, was heated.

The temperature of roll 10 and the speed of each roll are shown in Table 3.

The ribbon of filament from each spinneret is rolled into roll 12.
After the zero pass, there was an equal split between the M- and X-deflected jets.

Three jets were used for a cross-machine direction laydown at the upstream end of the moving belt, and the other three jets were used for a machine direction laydown relatively close to the downstream end of the moving belt.

Each ribbon of continuous filaments was charged as in Example 1 before entering the corresponding jet.

The nonwoven web was assembled onto a moving belt whose speed was adjusted to provide a basis weight of approximately 101.5 P/i (3.0 ounces per square yard).

Using the process and operation described above, under the conditions shown in Table 3, 101.5 P/m" (3.0 oz/sq.
Three 88.8 crn (33 inch) wide webs were produced with a basis weight of .

Fiber properties and average sheet properties are shown in Table 4.

Although web 1 is within the scope of the invention, webs 2 and 3
are not within the scope of this invention.

It should be understood that relatively small amounts, ie up to 20%, of additional layers may be present in the sheet.

For example, the sheet can consist of an MXM layered structure, so long as the outer -M layer accounts for at least 40% by weight and the -X layer accounts for at least 40% by weight of the total sheet.

Example 3 A melt flow rate of 3.2 (ASTM) was achieved using one jet for cross machine direction deflection at the upstream end of the belt and one jet for cross machine direction deflection at the downstream end of the belt. A nonwoven web consisting of continuous filaments of isotactic polypropylene was prepared from the polymer.

Polypropylene filaments were extruded through two spinnerets at a temperature of 250°C, each with a throughput of 0.381 m of 0.61'/min/hole.
It had 500 holes with a size of m (0.015 inches).

The bundle of filaments from each spinneret was split into two ribbons of parallel filaments with a binder/matrix ratio of 31/69.

The filaments were advanced and drawn over six rolls as shown in FIG.

Because this device did not use grooved rolls, it provided uniform rather than segmental stretching.

To achieve a difference in orientation between the binder and matrix filaments, 31% of the filaments from each spinneret are directed onto a guide past the first two propelling rolls, while the rest 69% of
I passed it over a whole roll of books.

Referring to FIG. 3, a filament 50 is placed into a spinneret 51
Extruded from.

Using the guides 52 and 61, the filament is
and 71 into two ribbons.

The ribbon 71, which accounts for 69% of the filament, is attached to the guide 6.
After passing over 2 rolls, it passed over 6 rolls 63.64, 54, 55, 56 and 57.

This filament ribbon 71 was given filaments with a high degree of molecular orientation by drawing on six rolls.

This orientation was achieved in two steps, first between rolls 64 and 54 and then between rolls 55 and 56.

The stretching conditions are shown in further detail in Table 5.

Rolls 64 and 55 are smooth rolls, each with 1
Heated to 35°C.

Filaments 70 from spinneret 51, which accounted for 31% of the total filaments, bypassed rolls 63 and 64 by passing over guides 52 and 53.

These filaments passed through rolls 54, 55, 56 and 57 and had a milder molecular orientation than the filaments from ribbon 71.

The combined ribbon 72 of both filaments with high and low molecular orientation was passed through an electrostatic charging device consisting also of a multi-contact electrode 73 and a grounded cylindrical electrode 74.

The charged filament was then passed into a jet 59 with a primary air supply 75 and a secondary air supply 76.

The primary air flow carried the ribbon of filament to the collection surface 60.

Secondary airflow 76 provided an oscillating airflow 77 of filaments.

The filaments from the second spinneret were treated in a similar manner, however, these filaments passed into a jet that vibrated the filaments in a cross direction.

These filaments 78 were deposited upstream on the same belt.

The resulting sheet had an XM morphology containing 50% by weight in the X layer and 50% by weight in the M layer.

The properties of this sheet are shown in Table 6. The values in Tables 2.4 and 6 for Examples 1.2 and 3 are based on proper control of directionality, use of a high percentage of binder in each layer, use of high denier in the matrix filaments, and at least 2 By using .8 strength, 25 at 1% neckdown.
~36 kg (55-79 lb) tufted tongue tear value of 101.5 g/m” (3 oz/sq yd)
It has been shown that this can be achieved for an XM-aligned sheet with a basis weight of .

These numbers also indicate that the sheets of the present invention retain a large percentage of their tufted tongue tear values after latex application.

[Brief explanation of the drawing]

FIG. 1 is a conceptual representation of the MX-type fabric described herein, showing sheets deposited on a surface moving from right to left in the method of the invention. FIG. 2 shows the arrangement of the apparatus as used for Examples 1 and 2. FIG. 3 shows the arrangement of the apparatus as used in Example 3.

Claims (1)

[Claims] 1 Consists of a layer oriented in the length direction of the cloth forming one surface of the cloth and a layer oriented in a direction perpendicular to the length direction of the cloth, each layer comprising a Bairada filament and a layer oriented in a direction perpendicular to the length direction of the cloth. a bonded layered non-woven fabric of isotactic polypropylene continuous filaments having a tenacity of at least 2.5 P/denier, each layer accounting for 40-60% of the weight of the fabric; The matrix filaments have an average denier of at least 12, each layer contains 18 to 50% binder filaments by weight, and the MD layers oriented along the length of the fabric have a □ value of at least 3.0. , and the layer oriented in the direction perpendicular to the length direction of the fabric DL has a MDL less (both have a □ value of 3°0, where XDLDL is the direction perpendicular to the length direction of the fabric of the layer) is the measure of the total filament length in
Also, MDL is a measure of the total filament length in the longitudinal direction of the fabric of the layer), and the filaments of the layered dishcloth have the following directionality value with respect to the entire fabric: MD -> 1.5 45° MD -> 1.5 45° and MD+XD - 3,5 to 30 45°. is a measure of the total filament length, MD is a measure of the total filament length of the entire fabric in the length direction of the fabric, and the 45° symbol is ±45° relative to the length of the fabric.
average of the total filament length measures of the entire fabric in two directions of 45°, where XDL, MDL, MD, XD and 45° are measures measured by the Randomer method. Non-woven fabric mentioned above.