MXPA01003352A - Differential basis weight nonwoven webs - Google Patents

Abstract

Differential basis weight nonwoven webs and a process for producing the webs is disclosed. In particular, the webs contain areas of higher basis weight and areas of lower basis weight. For instance, in one embodiment, the higher basis weight areas and the lower basis weight areas form alternating columns. The webs can be made according to a spunbond process or a meltblown process using a thermoplastic polymer or an air laid process using pulp fibers. The nonwoven webs are particularly well suited for use in diapers and other liquid absorbent products.

Description

NON-WOVEN FABRICS OF DIFFERENTIAL BASE WEIGHT Field of the Invention The present invention is generally directed to non-woven, laminated fabrics containing the non-woven fabrics to a process for forming the fabrics. More particularly, the present invention is directed to melt bonded fabrics having areas of lower basis weight and areas of higher basis weight.

Background of the Invention Polymeric and cellulosic articles, such as fibers and fabrics are useful for a wide variety of applications. For example, thermoplastic polymer fibers, pulp fibers, and fabrics have been used in the past to make fluid absorbing wipes, towels, industrial garments, medical garments, medical covers, and the like. Such items are also used in recreation applications, such as making tents and car covers. Non-woven fabrics made of polymeric fibers have also achieved widespread use especially in the manufacture of personal care articles, such as diapers, women's hygiene products and the like.

The non-woven fabrics identified above particularly refer to fabrics made through spunbonded, meltblown, coform or woven and carded processes. For example, spunbonded fabrics are typically produced by heating a thermoplastic polymer resin to at least its softening temperature. The polymeric resin is then extruded through a spinner to form continuous fibers which can then be subsequently supplied through a pull unit and fiber. From the pull unit and fiber, the fibers are extended to a perforated surface where they are formed into a fabric. In particular, a vacuum is created below the perforated surface by forming a suction force which pulls the fibers to the perforated surface. The formed tissue is then bonded such as by chemical, thermal or ultrasonic means.

Meltblown fabrics, on the other hand, have been conventionally made by extruding the thermoplastic polymer material through a matrix to form fibers. As the molten polymer filaments exit the matrix, a high pressure fluid, such as heated air or steam, attenuates the molten polymer filaments to form the fine fibers. The surrounding cold air is induced inside the hot air stream which then cools and solidifies the fibers. The fibers are then deposited in orange blossom on a perforated surface to form a fabric. The fabric has integrity to be made but can be additionally attached.

Carded and bonded fabrics refer to fabrics produced by carding a block of fibers. Once the block of fibers is carded into a fabric, the fabric can be folded and punctured with needles in order to increase the thickness of the fabric. When fibers made of synthetic polymers are used, in order to increase the strength and integrity of the fabric, the fibers can be melt bonded together. For example, the carded fabric can be brought into contact with a heated roller which is at a temperature sufficient to soften the synthetic polymer.

Coform fabrics generally refer to polymeric non-woven fabrics containing a filler. The filler incorporated in the fabric can be, for example, absorbent particles, pulp fibers, or other solid materials.

For most applications, non-woven fabrics typically must exhibit a combination of physical properties that make the fabrics very suitable for their intended function. For most applications, non-woven fabrics must have adequate softness, strength and absorbency characteristics. For example, the liners used in diapers, women's hygiene products, and other liquid absorbable products must be relatively strong, but they must be highly permeable to the liquid to allow liquids to make contact with the surface of the liner to be absorbed inside the product.

Unfortunately, when a property of a non-woven fabric is improved, typically other properties of the fabric are adversely affected. For example, when the liquid permeability of the non-woven fabrics is increased, often the fabric strength is decreased.

Currently, there are several needs for methods to control the properties of non-woven fabrics. There is also a need for non-woven fabrics exhibiting a combination of improved properties, such as liquid permeability and strength characteristics.

Synthesis of the Invention The present invention is directed to further improvements for producing non-woven fabrics having desired properties.

Therefore, an object of the present invention is to provide a process by means of which the physical properties of a non-woven fabric made of polymeric fibers can be controlled.

Another object of the present invention is to provide novel non-woven fabrics exhibiting a desirable combination of properties.

Yet another object of the present invention is to provide non-woven fabrics having a controlled variable basis weight made of polymer fibers or pulp fibers.

It is another object of the present invention to provide non-woven fabrics having the first areas and the second areas forming a predetermined pattern and wherein the basis weight of the fabric within the first areas is greater than the basis weight within the second areas. areas.

Still another object of the present invention is to provide laminates containing a non-woven fabric which has a variable basis weight.

These and other objects of the present invention are achieved by providing a non-woven fabric made of polymeric fibers, such as fibers made from a spinning or meltblowing process. The non-woven fabric defines the first areas having a first basis weight and the second areas having a second basis weight. In particular, the first areas have a basis weight of from about 1.5 to about 5 times greater than the basis weight of the second areas and particularly from about 1.5 to three times greater than the basis weight of the second areas. In general, the average fabric basis weight can vary from about 0.2 ounces per square yard to about 9 ounces per square yard and particularly from about 0.3 ounces per square yard to about 4 ounces per square yard.

The first and second areas contained within the fabric can be formed according to an orange blossom pattern or according to a pattern on the forming wire which locally controls the air flow rate. For example, the first and second areas may form alternating columns, alternating columns and rows or may form a pattern of squares within the tissue. The pattern of pictures can be formed by the heavy area that forms the grid or the light area that forms the grid. For most applications, the first areas may comprise from about 25% to about 75% of the non-woven fabric, and particularly from about 40% to about 60% of the non-woven fabric.

The polymeric fibers used to produce the non-woven fabric can be made of various materials including elastomeric polymers, polypropylene, polyethylene, polyester and nylon. The fibers may be monocomponent fibers or multi-component fibers, such as bicomponent fibers. The fibers can also be continuous filaments or discontinuous filaments. Where a high foaming is desired, crimped fibers may be used.

In addition to the non-woven fabrics described above, the present invention is also directed to laminates incorporating fabrics. For example, in one embodiment, a rolled product can be produced in which a spunbonded fabric as described above is laminated with a meltblown fabric. In a further alternate embodiment, a meltblown fabric can be placed between two outer layers of spunbonded fabrics, in which at least one of the fabrics bonded with spinning has a variable basis weight. In yet another embodiment, the laminate may contain a film in addition to other non-woven fabrics.

The non-woven fabrics of the present invention have areas of a higher basis weight and a lower basis weight and are generally produced by extruding a thermoplastic polymer through a matrix to form the fibers. The fibers are directed to a perforated surface by means of a flow of which is created by a vacuum under the perforated surface. According to the present invention, the perforated surface has a predetermined pattern of sections or regions of lower and higher permeability.

A non-woven fabric is formed on the perforated surface of the fibers. The formed fabric defines the first areas having a first basis weight and the second areas having a second basis weight that is lower than the first basis weight. Specifically, the second areas are formed on the perforated surface where the lowest permeability sections are located.

In a spinning process, after being extruded the fibers are pulled through the fiber pulling unit. From the fiber pulling unit, the fibers are directed to a perforated surface. The distance between the fiber pulling unit and the perforated surface can be, for example, from about 22.86 cm to about 50.8 cm (9 inches to about 20 inches).

Other objects, features and objects of the present invention are discussed in more detail below.

Brief Description of the Drawings A complete and enabling description of the present invention including the best mode thereof for a person with an ordinate skill in the art, is more particularly set forth in the remainder of the description, including reference to the drawings to the accompanying figures in which : Figure 1 is a schematic drawing of a spinning process for producing non-woven fabrics; Figure 2 is a plan view of an incorporation of a non-woven fabric made in accordance with the present invention.

Figure 2A is a side view of an embodiment illustrated in Figure 2.

Figure 3 is an alternate embodiment of a non-woven fabric made in accordance with the present invention.

Figure 4 is a further alternate embodiment of a non-woven fabric made in accordance with the present invention.

The repeated use of the reference characters in the present description of the drawings is intended to represent the same or analogous features or elements of the invention.

Detailed Description of Preferred Additions It should be understood by one of ordinary skill in the art that the present discussion is a description of the embodiments of examples only, and is not intended to limit the broader aspects of the present invention, the broader aspects of which are included in the scope of the invention. construction of examples.

The present invention is directed to non-woven fabrics such as spin-knitted fabrics, melt-blown fabrics, coform fabrics, laid fabrics or bonded and knitted fabrics having areas of higher basis weight and weight basis areas lower. As used herein, the basis weight of a fabric refers to the mass of the material per unit area. For example, the basis weight can be measured according to the ASTM test number D 3776-96 option C and can be measured in ounces per square yard. Differential basis weights may be contained within the non-woven fabric according to an orange blossom pattern or according to a predefined pattern.

The ability to produce non-woven fabrics having a differential basis weight offers several benefits and advantages. For example, the differential basis weight can provide a stability of mechanical strength in the direction of the upper basis weight areas and a stability or low resistance in the areas of lower basis weight. Therefore, a given pattern can be used to adjust and control the strength and stability of the fabric in the machine direction or in the transverse direction. Similarly, the upper and lower base weights provide areas of high liquid and / or gas / vapor permeability which may be useful for managing and controlling the fluid. These advantages are present in high-fluff tissues or low-fluff tissues.

Non-woven fabrics made according to the present invention can be used in many different and different applications. For example, non-woven fabrics are particularly well suited for use in laminates that are used to make such products as garments, especially breathable garments, diapers, cleansing wipes, women's hygiene products and the like. Non-woven fabrics can also be used as filters, especially when the filtering zone is required or beneficial. It has also been found that by stretching a non-woven fabric according to the present invention, the fabric has been shown to have potential as a curl material in hook and loop fasteners, such as VELCRO fasteners.

In one embodiment of the present invention, the non-woven fabric is either used as a sprouting material, as a lining material or as an outer covering in a diaper or other similar product. Fabrics made according to the present invention are particularly well suited for these applications due to their handling characteristics and fluid control together with their strength characteristics. In particular, the light basis weight portions of the fabric will pass the fluids to an absorbent material, while the higher basis weight areas provide the necessary strength for such applications. In fact, it has been discovered that lower base weight areas create channels within the tissue within which liquids are directed, providing the fabric with greater liquid permeability, low runoff properties and fluid distribution properties.

In the past, in order to produce fabrics with high liquid permeability and adequate strength, typically the fabrics had to be treated with a surfactant in order to increase the wetting of the fabric while maintaining the strength. High strength fabrics that have low runoff properties, however, can be produced according to the present invention without the need for surfactants.

A process for producing non-woven fabrics having a variable basis weight according to the present invention will now be discussed in detail with reference to Figure 1. In particular, Figure 1 illustrates a spin-bonding process. It should be understood, however, that other processes can be used to produce the fabrics of the present invention. For example, in an alternate incorporation, the fabrics can be produced according to the processes of blowing with fusion, to a process of placing by air, to a coform process, to a carding process and joined. More generally, any process can be used which controls the formation of material made of filaments and / or fibers by the application of an air flow such as that which is generated by a vacuum.

Returning to Figure 1, a process line and ten are described for preparing a non-woven fabric according to the present invention. The process line ten is arranged to produce continuous monofilaments, but it should be understood that the present invention comprises non-woven fabrics made of other types of fibers including multi-component filaments having two or more components, discontinuous filaments or even pulp fibers.

The process line 10 includes an extruder 12 to extrude a polymeric material. The polymeric material is fed to the extruder from a hopper 14. From the extruder 12, the polymeric material is fed through a conduit d polymer 16 to a spinner member 18.

The spinning organs for extruding the filaments are well known to those with an orderly skill in the art and therefore are not described in detail here. Generally described, the spinner member 18 includes a box containing a spin pack which includes a plurality of plates stacked one on top of the other with a pattern of openings arranged to create the flow paths to direct the polymeric material to through the spinner organ. The spinning organ 18 has round or shaped capillary cups arranged in one or more rows and / or in one or more columns. The openings of the spinning organ form a curtain extending downwardly of the filament when the polymer is being extruded through the spinning organ.

The polymeric material used to form the filaments can any suitable thermoplastic polymer. For example, the polymeric material can be a polyolefin such as a polyester, a nylon or mixtures thereof. The polymeric material can also be elastomeric polymers such as polyurethanes, polyetheramides, polyether esters, elastomeric polyolefins etc. In a preferred embodiment, the filaments are made of polypropylene.

An aspirator or fiber pulling unit 22 is placed below the spinner member 18 and receives the filaments. Fiber pulling units or vacuum cleaners for use in confound spinning polymers are well known as discussed above. Fiber pulling units suitable for use in the process of the present invention include a linear fiber vacuum cleaner of the type shown in U.S. Patent No. 3,802,817 and seductive guns of the type shown in the patents of the United States of America. United States Numbers 3,692,618 and 3,423,266, the descriptions of which are incorporated herein by reference.

Generally described, the fiber pulling unit 22 includes an elongated vertical conduit through which the filaments are pulled by the suction air entering from the sides of the conduit and flowing downwardly through the conduit. A compressor or blower with or without a heater 24 supplies the suction air to the fiber pulling unit 22. The suction air pulls the filaments and the ambient air through the fiber pulling unit.

An endless perforated forming surface 26 is placed below the fiber pulling unit 22 and receives the continuous filaments from the outlet opening of the fiber pulling unit. The forming surface 26 moves around the guide rollers 28. A vacuum 30 placed below the forming surface 26 where the filaments are deposited pulls the filaments against the forming surface.

As shown in Figure 1, the forming surface 26 comprises an endless wire which travels around the guide roller 28. In an alternate embodiment, however, a drum forming unit can be placed under the pull unit of fiber 22 and may contain a forming surface for receiving the filaments.

The process line 10 further includes a joining apparatus such as thermal point attachment rolls 34 (shown in phantom) or a through-air linker 36. Thermal point linkers and air linkers are well known to those skilled in the art and are not described in detail here. Finally, the process line 10 includes a winding roller 42 to take the finished fabric.

In an alternate embodiment of the present invention, when it is desirable to curl the filaments as they are formed, a process line 10 may include a cooling blower 20 positioned on one side of the curtain of the filaments extending from the spinner member. 18. The air from the cooling air blower 20 cools the filaments. The heater or blower 24 can then be used to activate the latent curling of the filaments by causing the filaments to naturally curl. By using crimped fibers in the formation of the non-woven fabrics of the present invention various advantages are offered depending on the particular application. In general, the use of crimped fibers increases the swelling of the resulting fabric. By increasing the swelling, the ability of the tissue to absorb and / or transfer fluids can be increased. High-fluff fabrics are also typically desired when the non-woven fabric is used as a curl material in a hook and loop fastener. When used as a filter medium, high foaming fabrics provide improved filtration properties while maintaining lower pressure drops.

In general, to operate the process line 10, the hopper 14 is filled with a polymeric material. The polymeric material is melted and extruded by the extruder 12 and then directed into the polymer conduit 16 and the spinner member 18. The temperature at which the polymer is extruded depends on the particular polymer used. When polypropylene or polyethylene is used, the preferred temperature of the polymer when extruded ranges from about 187.7 ° C to about 276.6 ° C (370 ° F to about 530 ° F) and preferably from about 204.4 ° C. C at about 232.2 ° C (400 ° F to about 450 ° F).

From the spinner member 18, the filaments are pulled and the vertical conduit of the fiber pulling unit 22 by a gas flow, such as air from the blower or the compressor with or without a heater 24 through the pulling unit of fiber. The fiber pulling unit is preferably placed 76.2 cm to 152.4 cm (30 to 60 inches) below the bottom of the spinner member 18.

The filaments are then deposited through the outlet opening of the fiber pulling unit 22 to the moving forming surface 26. The vacuum 30 pulls the filaments against the forming surface 26 to form a non-woven fabric and does not united of continuous filaments. If necessary, the fabric is then lightly compressed by means of a compression roller 32 and then joined thermally with the rollers 34 or through the connection with air in the jointer via air 36.

In addition to using the air-through or thermal-point joiners, the fabric can also be joined through other methods. For example, the tissue may be joined through the hydroentanglement or through needle piercing. It should be understood, however, that unbound tissues can be made in accordance with the present invention.

Finally, the finished fabric is wound onto the winding roll 42 and is ready for further use or treatment.

According to the present invention, in order to form a non-woven fabric having regions of an upper and lower basis weight in a different pattern, in a corporation, the forming surface 26 may include a corresponding pattern of upper air permeability areas and areas of lower permeability. In other words, the suction air that is being generated by a vacuum 30 is blocked or restricted according to a particular pattern in the forming surface 26 which is under the landing zone of the filaments coming out of the pulling unit. fiber 22. In this way, a higher density of filaments is pulled to the areas of a higher air permeability in the forming surface 26 while a lower density of filaments is pulled to the areas of lower permeability. By blocking parts of the forming surface, the lower air velocity and air velocity areas through the forming surface 26 are created.

The manner in which the forming surface is blocked out may vary depending on the desired result. For example, a coating such as rubber or caulking can be placed on the forming surface where non-permeable areas are desired. Alternatively the forming surface can be manufactured with a variable grid mesh to create different permeabilities. According to the present invention, the areas of lowest permeability can be created by completely blocking the vacuum forming surface 30 or by creating a difference of permeability in or on the forming surface.

When a non-woven fabric is used in the process as described above, some precautions may be required in order to prevent the fabric from losing its integrity. For example, in an embodiment, a perforated plate can be placed on the fabric. The high air pressure can then be blown through the perforations. The filaments under the perforations can then be struck by high velocity air and forced to move outward from the air jets which would create areas of lower base weight similar to the process described above.

The amount of difference in the basis weight that is formed in the tissue will depend on several factors. For example, the extent to which the basis weight in the fabric differs will depend on how the forming surface is blocked and the amount of suction force created by the vacuum 30. Also, the difference in basis weight in the fabric can be increased or decreased by increasing or decreasing the distance of the displacement of the filaments between the fiber pulling unit 22 and the forming surface 26. For exampleBy increasing the distance between the fiber pulling unit and the forming surface, greater differences in the basis weight will be created. This is because the filaments are moving at a slower speed between these are further away from the output of the fiber pulling unit, and the forming wire air can have a greater effect on the location of the filaments that stick in the forming wire. For most applications, the fiber pull unit 22 may be about 22.8 cm to about 50.8 cm (9 inches to about 20 inches) from the forming surface 26.

The manner in which the basis weight of a fabric made in accordance with the present invention will vary, in this embodiment, will generally depend on the manner in which the permeability of the forming surface is varied. For example, at one end, the forming surface can have completely open areas of permeability and completely closed areas of permeability creating the largest amount of difference in basis weight. Alternatively, the forming surface may have a permeability profile in which the permeability of the forming surface gradually decreases from the higher permeability areas to the lower permeability areas. In this embodiment, the basis weight of a fabric formed on the surface will gradually decrease from the areas of basis weight greater than the areas of lower basis weight in a controlled and predetermined manner as desired. The manner in which the basis weight is varied within a fabric will generally depend on the particular application.

In addition to blocking the forming air in a melt spinning process, a base weight difference can be formed in non-woven fabrics in other shapes. For example, in an alternate embodiment, a regularly formed tissue can be formed to create the lowest base weight areas on the fabric. In particular, a relatively heavier weight knitted fabric can be perforated according to a particular pattern and then a light layer of extruded filaments, such as filaments spun onto the upper part of the perforated fabric can be formed in order to provide the fabric with continuity and resistance.

Non-woven fabrics of differential basis weight made in accordance with the present invention can be made having an almost unlimited variety of different patterns with respect to where the upper basis weight areas and the lower base weight areas are located. For example, the areas of basis weight s - .. per.:r and the areas of weight b ^ and lower p ed3n s < f > .? p ?? . .r. • Pit to the predetermined orange blossom can be farmed - '? _' i r .. '' -é * r: ro.In particular, weight of the weight of the base weight mfexior orja Alternate, alternate, and alternate columns, or they can form &ct; cc. cs c of cadres. : r_ -_- jo o. a _cs ": r_;" -c :; _ and a? a:; c r_ _. ~. ccr e_ ..?. te-o -7, u-cn of acuei .- co: the present invention is _ illustrated. In the case of non-woven fabric 50, it includes the t-areas. c.so lower case 52 and the case weight case sioericr 5. c ^ 1 ^ sa showed, the areas of base weight s ba; c 51 _, the areas Je peso __ase s pepc 54 feri C3l_? r.? .s alternate-_epend? ena_ = _ _ particle application! , the lines can be formed in the direction of the Tiquir or they can be lined perpendicularly. to the direction of the machine, by exercise, in ia the co_.umr. s sn ^. er. dilecció to the machine, the resiscencic a_ ej gone v cev rsa Z ~ ostión de l ^ p? I "s radc en le f? G__ a _. _- zz er.cc .'.- = q _e -3 ^ -:? o .larmer.te dir-c_ d "p < _-r¿ use se: ctc c ae aos-rüer.ces _ e. -.as "tp LL CO * xor.es, = 1 aeche d- columns can vary from about 1/8 of an inch to about an inch. The width of the upper basis weight columns and the lower base weight columns may be the same or may vary within the above range.

Referring to Figure 3, an alternate incorporation of a generally indicated fabric with the number 60 made in accordance with the present invention is illustrated. In this embodiment, the upper basis weight areas 64 form the columns and rows in the fabric. The lower base weight areas 62, on the other hand, appear as squares separating the columns and rows. This design maintains the strength of the fabric in the machine direction and in the direction transverse to the machine.

If desired, in one embodiment, the nonwoven fabric 60 may include the upper basis weight areas 66 located where the rows and columns intersect. The higher basis weight areas 66 may have a basis weight that is greater than that of the areas 64. In this manner, the fabric 60 includes 3 different basis weight areas which form a base weight difference particularly well suited for use in the absorbent liquid and filter applications.

An additional alternate incorporation of the nonwoven fabric generally indicated with the number 70 made in accordance with the present invention is illustrated in Figure 4. As shown in this embodiment, a pattern of squares is formed by the lowest base weight areas 72 and the upper weight basis areas 74.

Yet another alternate incorporation of a generally nonwoven fabric made in accordance with the present invention is illustrated in Figure 5. As shown in this embodiment, the fabric includes the lower weight areas 84, which appear in the form of Small discrete shapes such as dots, which are arranged according to a geometric pattern. Alternatively, the points however 84 may be arranged at orange blossom. The tissue surrounding the dots comprises an area of upper basis weight 82.

In this embodiment, the small discrete shapes of lower basis weight can be formed in the fabric in order to provide areas of superior permeability for the passage of gases, vapors or liquids. By appearing in small discrete forms, the fabric's resistance does not unduly compromise.

It should be understood, however, that in addition the different illustrated embodiments can be formed in many different different patterns in the fabric depending on the particular application. In addition, the fabrics can be formed according to the present invention which includes more than one pattern formed on the same sheet.

In addition, apart from the patterns described above, logos, designs and watermarks may also be formed in the fabric according to the present invention. For example, the forming surface can be blocked with a word, phrase or logo, which can make the word, phrase or logo appear in the material as a lower base weight area.

In yet another embodiment, a fabric made in accordance with the present invention may include, a single lower base weight area that is positioned at a particular location on the fabric where the superior permeabilities are desired. For example, in one embodiment, the fabric of the present invention can be used as a diaper liner. A diaper lining is the material that is placed on one side of the wearer's body. Preferably, a diaper liner is permeable to liquid so that liquids are pulled out of the diaper wearer and absorbed into the interior of the diaper. According to the present invention, a diaper liner can be constructed that includes a lower base weight permeability area in the "target area" of the diaper where the diaper is more likely to come in contact with the liquids.

For example, for most applications, the target area may be the crotch area of the diaper. In this manner, a diaper liner can be constructed including a lower base weight, a higher liquid pervious area as desired, while also having areas of higher basis weight to provide resistance to the garment. Heavy weight areas also prevent fluid from flowing back to the skin. As described above, in this embodiment, the base weight of the diaper liner may also go directly from high to low in the target area or may vary gradually from the areas of basis weight greater than the lowest base weight area so that The lowest base weight contained in the fabric is located directly in the center of the target area. In this form, the diaper liner may contain a lower base weight area that possibly maximizes its strength. This lower base weight target area may be, for example, 5.08 cm wide and 10.16 cm long (2 inches wide and 4 inches long).

Alternatively, a fabric made according to the present invention may include a single upper weight basis area that is positioned at a particular location in the fabric where the lowest permeabilities are desired. The upper basis weight area may be surrounded by a lower weight basis fabric.

The proportion of the base weight areas above the lower base weight areas can also be varied as desired. For most applications, however, the upper basis weight areas should comprise from about 25 percent to about 75 percent of the total surface area of the fabric. More particularly, the upper basis weight areas may comprise from about 40 percent to about 60 percent of the tissue. In a preferred embodiment, 50 percent of the surface area of the fabric comprises areas of higher basis weight while the remaining 50 percent of the fabric comprises areas of lower basis weight.

The ratio between the basis weight of the upper basis weight areas and the base weight of the lower base weight areas may also vary. In general, the areas of higher basis weight can be from about 1.5 to about 5 times greater than the basis weight of the lower base weight areas and can be from about 1.5 to about 3 times larger than the lowest base weight areas. For almost all applications, the basis weight of the upper basis weight areas and the lower base weight areas will fall within the range of from about 0.2 ounces per square yard to about 9 ounces per square yard depending on the application particular.

Non-woven fabrics of differential basis weight made in accordance with the present invention can be used either alone or in combination with other materials. For example, non-woven fabrics can be combined with other fabrics of material to form a laminate. In one embodiment, for example, the non-woven fabric of the present invention produced as described above can be combined with other woven fabrics, woven fabrics, and / or films, such as polymer films. A particular laminate product that can be made according to the present invention includes a melt blown nonwoven fabric placed between two outer spunbonded fabrics, in which at least one of the outer spunbonded fabrics has a differential basis weight of according to the present invention. In this embodiment, the yarn-bonded fabrics provide durability while the internal melt blown fabric provides a barrier layer which is porous but which inhibits the transfer of fluids from the interior of the fabric laminate to the exterior.

A multilayer laminate as described above can be formed by a number of different techniques including but not limited to using adhesives, needle punching, ultrasonic bonding, thermal calendering and any other method known in the art. Such laminates are useful for a wide variety of applications. For example, such laminates can be incorporated into wipes, towels, industrial garments, medical garments, medical covers, surgical gowns, foot covers, sterilization wraps, diapers, women's hygiene products as well as various other products.

In one embodiment, a process for producing laminates according to the present invention may include the steps of first building a differential basis weight fabric over a patterned wire and then transferring the unbonded tissue to a second forming surface to form a second layer. on top of the already formed fabric. This process can be repeated until a desired number of layers have been put together. Once the layers have been stacked, the laminate can then be bonded through eg heat. The different layers contained within the laminated product can each have a differential basis weight in a selected pattern or alternatively some of the layers can have a constant basis weight. Furthermore, in this embodiment, the layers can be made from the same process, such as a spinning process or can be made from different processes including a meltblowing process, a bonded and bonded process, a coform process or a process of placed by air. According to this embodiment, the laminated products can be produced having a particular and desired permeability profile.

In addition, non-woven fabrics having a differential basis weight of the present invention are also directed to other fabric constructions that may not only have good drainage properties but also good strength properties as well. In order to achieve these objectives, in this embodiment, the present invention is directed to fabric constructions containing a lightweight nonwoven fabric in combination with a strength improving material.

The light weight nonwoven fabric is provided to give the fabric integrity, a desired appearance and a desired feel. The lightweight nonwoven fabric can be made, for example, of a basis weight of less than about 13.6 g / m2, and particularly of 10.2 g / m2. At these base weights, the fabric has excellent draining properties and will allow a liquid to make contact with the fabric to flow through it. The non-woven fabric can be made according to various processes such as the meltblowing process or a spinning process.

Even when exhibiting good runoff properties, a lightweight nonwoven fabric as described above generally will not have good strength characteristics. Accordingly, according to the present invention the lightweight nonwoven fabric is combined with a strength improving material, which may be, for example, a polymer grid or alternatively a non-woven fabric made of macro fibers. It has been discovered by one of the present inventors that combining a lightweight nonwoven fabric with a grid material or with a nonwoven fabric made of macro fibers generally increases the strength of the light weight fabric without adversely affecting the properties of tissue runoff.

The grid material combined with the lightweight nonwoven fabric can be made, for example, polymeric filaments, such as nylon monofilaments or polyester monofilaments. The grid material must have a mesh size large enough not to inhibit the flow of a liquid through the fabric. For example, in one embodiment, the grid material may have a mesh size of about 18 x 18 (wires x inch).

In an alternate embodiment, instead of combining the non-woven fabric with a grid material, the fabric can be combined with a second non-woven fabric made of macro fibers. It has been found that fabrics made of macro fiber are very strong but have excellent draining properties. The non-woven fabric made of the macrofibers can contain basic fibers, meltblown fibers or spunbond fibers. The fibers should have a diameter of at least 20 microns, particularly from about 30 microns to about 80 microns and more particularly from about 40 microns to about 60 microns.

The grid material or the non-woven fabric made of the macro fibers can be combined with a non-woven fabric of light weight according to various methods including but not limited to using adhesives, needle piercing, ultrasonic bonding, thermal calendering and any other method known in the art. Such fabric constructions can be used in any of the laminates described above and are particularly well suited for use as liners in liquid absorbent products.

The present invention can be better understood with reference to the following examples: The following tests were carried out in order to demonstrate the improved properties of the non-woven fabrics made in accordance with the present invention.

EXAMPLE 1 (CONTROL) A non-woven fabric bonded with lightweight yarn having a basis weight of 12.5 grs / 2 was produced.

Run-off tests were carried out on 3 different samples of the non-woven fabric joined with spinning. During these tests, 100 ml. of water (at a temperature of about 37 ° C) were applied to the samples of the spunbond fabric. In particular, the samples were placed on a 30 ° inclination on a liquid absorbing material. During the tests it was noted that at the point on each sample where the water was sticking on the cloth bound with yarn. The water began to soak through the absorbent material and was immediately absorbed. As the water moved around a distance of 7.62 cm (3 inches), most of it was absorbed on its way down to the liner. In fact, the runoff data for these samples showed that the first and third samples each produced a zero runoff, while the second sample produced only one runoff of 1 milliliter. Therefore, these samples of spunbond non-woven fabric produced little or no runoff during experimentation, which was expected from a lightweight fabric.

EXAMPLE 2 In this example, the tests were carried out in order to examine the runoff results when multiple layers of spunbond non-woven fabrics are stacked together compared to a non-woven fabric made in accordance with the present invention.

In the initial test, 2 layers of the spunbonded fabric of 0.37 ounces per square yard were stacked together, made according to Example 1 and the amount of runoff observed was 6 milliliters.

Subsequently, a fabric was created according to the present invention. When creating the sample, a rectangular sheet of yarn bonded fabric of 0.37 ounces per square yard was used as the background layer. Next, the 2.54 cm (1 inch) wide strips of the 0.37 oz. Yarn per square yard yarn were adhered to the bottom layer using a spray adhesive made by 3M. Two of these strips (stacked one on top of the other) were adhered to the lower layer at approximately 2.54 cm (1 inch) intervals forming horizontal strips, therefore, the samples included 2.54 cm strips (1 inch) wide of only one layer of spunbonded fabric (0.37 ounces per square yard) between 2.54 cm (1 inch) wide strips of 3 layers of spunbonded fabric (1.11 ounces per square yard) 37.6 grams / m2)). An example of such a sample is shown in Figure 12 wherein the lower basis weight areas 52 may represent areas of only a single layer of the spunbonded fabric and the upper basis weight areas 54 may represent areas of 3 layers of fabric joined with yarn.

The runoff tests were carried out on the sample and the following data were collected. The sample was arranged so that the strips were placed perpendicular to the water flow.

Runs numbers 1-4 involved the fluid that stuck into the sample in the areas of 3 heavy layers of the spunbonded fabric, while run numbers 5 and 6 involved gluing in the areas of a lighter layer. In most runs, almost all fluid was absorbed into the tissue material. During runs 4 and 6, however, it appeared that the fluid was found in a low wettability channel and drained as a result of finding this channel.

In general, the object of the present invention is to produce a non-woven fabric having the draining properties of a lightweight fabric but the strength of a heavier fabric. As shown by this example, the sample made in accordance with the present invention has the runoff properties comparable to a single layer of the spun bonded nonwoven fabric, while having high strength areas that had a basis weight greater than 33.9. grs / m2.

EXAMPLE 3 In this example, an alternate sample of a nonwoven fabric was made in accordance with the present invention, which included a grid pattern of areas of 1.2 and 3 layers of spunbonded cloth. The same yarn-bound fabric described in Example 1 was used to make the sample. The sample was made by first placing 2.54 cm (1 inch) wide strips of the spunbond fabric on a lower layer of the fabric and attaching these strips to the lower layer using the above-mentioned sprayed adhesive. Subsequently, more 2.54 cm (1 inch) wide strips of the spunbonded fabric were placed on top of the lower layer in a direction perpendicular relative to the first layer of strips. Therefore, a grid type pattern of one, two and three layer areas was established.

An example of such a sample is indicated in Figure 3 where the lower weight areas 62 may represent areas of only one layer of yarn-bonded fabric (0.37 ounces per square yard), areas of upper basis weight 64 may represent areas of 2 layers of yarn bonded fabric (25.1 grs / 2) and upper weight basis areas 66 can represent areas of 3 layers of knitted fabric (1.11 ounces per square yard). As seen in the example shown in Figure 3, the few areas that comprise a layer of spin-linked tissue were located on the sample of what were located in the sample described in Example 2 given above.

Runoff tests were carried out on the sample and the following data was collected.

It was seen during these runs that when the fluid stuck in a 2-layer area of the spunbonded fabric, most of the fluid moved down to that area of double layers. However, it was found that if the fluid flow was displaced to an area of only a single layer of spin-linked fabric, most of the fluid was absorbed.

Example 4 In this example, an additional alternate weave made in accordance with the present invention was created by cutting holes in a sheet of woven fabric bonded with yarn of 0.37 ounces per square yard and attaching this sheet to an uncut sheet of the fabric bonded with spinning through the use of the above-mentioned sprayed adhesive. Thus, this sample contained areas of a layer of knitted cloth and areas of 2 layers of knitted cloth. An example of such placement is shown in Figure 4 in which the lower basis weight areas 72 may represent the areas on the sample that contain only a single layer of a spunbonded fabric while the upper basis weight areas 72. they can represent the areas on the sample that contain 2 layers of tissue linked with spinning. It is evident that this sample contained approximately the same number of unique layer areas as the sample did in Example 3. Runoff tests were carried out on the sample and the following data was collected.

During the last run in this game, run number 4, the fluid was impacted only on one of the single layer areas of the spunbonded cloth at which time the fluid immediately passed through and saturated the absorbent material below. Then the runoff occurred.

Above all, the purpose for approving the different samples containing both the multiple layer and single layer areas of spunbonded fabric material was to determine the effectiveness of incorporating lower weight basis layers of spunbonded web material ( for softness and low fluid retention) with upper weight basis layers (for strength and durability) according to the present invention. In most cases, these samples demonstrated relatively low amounts of drained fluid and in turn exhibited the effectiveness of incorporating upper and lower basis weight areas of spunbonded material into the woven product for use in a diaper liner or the like.

Example 5 The following example was carried out in order to demonstrate the runoff properties of combining a grid material with a non-woven fabric. The sample produced is intended to work in a similar way to a canvas type material.

In this example, a sheet of yarn-bound cloth material of 0.37 ounces per square yard described in example one was placed on a nylon grid with a mesh size of 18 x 18. Five run-off tests were carried out on 5 different pieces of fabric joined with yarn placed on the nylon grid and the results were obtained as follows: As shown above, the sample exhibited excellent runoff properties.

Example 6 In this example of the present invention, a blown sheet with macrofiber melt from a non-woven fabric material was combined with a cloth bound with lightweight yarn and tested in run-off experiments.

The meltblown non-woven macrofibre fabric had a basis weight of 1.66 ounces per square yard (56.3 grs / 2). The macrofibers incorporated in the tissue had a diameter of approximately 50 microns. A runoff test was carried out on this macrofibre material by itself, and the amount of runoff observed was 2.6 ml.

This same sample of macrofibres was dried and placed under a sheet of yarn-bound material of 0.37 ounces per square yard described in example one. After the runoff test was carried out on this double layer system, and the amount of runoff observed was 2.5 ml.

Example 7 The following tests were carried out to demonstrate the improved properties of non-woven fabrics made in accordance with the present invention.

Spunbonded filament fabrics were produced similar to the processes generally described above with reference to Figure 1. In this example, the polypropylene filaments were made. The filaments used to make the fabrics had a denier of about 3.8 denier per fiber.

The non-woven fabrics were produced having base weights of 10.2 grs / 2, 14.9 grs / m2 and 20.3 grs / 2. In order to simulate various fabrics made according to the present invention, the rows of tape were placed on the samples of the base fabric of 0.3 ounces per square yard. By placing the tape on the tissue, those areas on the fabric became impervious to the liquid. The tape is intended to represent heavier weight basis areas that are not essentially liquid permeable. The tape was placed on the fabric in order to carry out and form alternating columns of open areas and of liquid impervious areas closed.

The liquid runoff properties of the tissues were tested. The liquid runoff test measured a capacity of the fabric to pass a liquid that comes into contact with said fabric. In general, a runoff test includes the steps of placing a sample of the fabric on an angled surface. Specifically, the angle of the surface to the horizontal is 30 °. The sample is placed on a retention material that is a liquid absorbent. In this example, the retention material included 3 layers of a coform material. The coform retention material was approximately 20.32 cm long (8 inches) and had a width of approximately 13.38 cm (5.27 inches).

A funnel was placed on top of the sample so that the bottom of the funnel was 10 mm. from the top of the sample. 50 milliliters of a salt water solution of 0.85% was placed in the funnel which were then poured on the sample for about a period of time of 15 seconds. The liquid contacted the target area that is approximately 17.78 cm (7 inches) from the bottom edge of the retention material. The amount of saltwater solution that runs off the fabric is measured. In general, a larger amount of collected liquid reflects a less permeable fabric. Conversely, very little or no runoff indicates that the tissue is highly permeable to liquid. In this aspect, as used herein, a tissue configured to pass liquids is defined as a fabric that will produce less than 5 grams of runoff when subjected to the test described above.

In this example when the taped fabrics were placed on the inclined surface, the columns were placed perpendicular to the flow of the solution.

From the above mentioned test, the following results were obtained: As shown above for conventionally produced fabrics having a uniform basis weight and containing 3.8 denier fibers per fiber, the amount of runoff increased linearly with increasing base weight. At base weights greater than about 22.7 grams / m2, practically all the solution that made contact with the tissue must be drained from the tissue indicating that the tissue did not allow any transmission of liquid.

With regard to the fabrics made to simulate tissues having a differential basis weight, it was observed that the amount of runoff will generally increase when the width of the closed areas is increased and when the width of the open area remains constant. It was also noted that the larger spaces between the closed areas improved runoff results. In general, the runoff of the taped fabrics was controlled by the size of the open areas (which represent lightweight weight areas, the actual basis weight of those areas, and the percentage of tissue that those areas covered.It was estimated that the strength (in the direction of the columns) of the fabrics made according to the present invention will be greater than the strength of the areas of light basis weight but somewhat lower than the strength of the areas of higher basis weight. It is believed that the base weight resistance of the fabric can be estimated by multiplying the base weight of the light weight areas times the number of light weight basis areas which is then added to the result of multiplying the base weight of the areas of weight basis heavier times the amount or percentage of heavier weight basis areas. For example, for a material with 1/4 inch strips, which has a basis weight of 0.3 ounces per square yard and strips that have a basis weight of 1.5 ounces per square yard (50.9 g / m2) the fabric must have a resistance (0.3 ounces per square yard) (50% of the fabric) + (1.5 ounces per square yard) (50% of the fabric) = 0.9 ounces per square yard. Therefore, the above mentioned fabric strength should be equivalent to a fabric having a constant basis weight of about 0.9 ounces per square yard (30.5 grs / 2). From the table mentioned above, on the other hand, runoff can be estimated as being around 12.7 grams which should be the equivalent of a constant basis weight fabric that has a basis weight of 0.39 ounces per square yard (13.2 grams / m2) if it is assumed that the runoff increases linearly with the base weight.

Example 8 The fabrics of bicomponent filaments joined with spinning were produced according to the process generally described above with reference to Figure 1. In this example, the bicomponent filaments were not crimped. The bicomponent filaments used to make the fabrics, included a polyethylene component and a polypropylene component in a side-by-side configuration. The polyethylene used to make the filaments was a linear low density polymer 6811A obtained from Dow Chemical and contained 2% by weight of Ti02.

The polypropylene used to make the filaments, on the other hand was Escorene 3445 obtained from Exxon Corporation and which contained 2% by weight of Ti02.

The polypropylene component and the polyethylene component were fed separate extruders. The extruded polymers were spun into round bicomponent filaments using a spinning die. From the spinning die the filaments were fed through a fiber pulling unit.

The pulled filaments were deposited on the perforated surface to form a non-woven fabric which was passed through a knit jointer. In this example, the Denier of the filaments was around 2 denier per fiber. The perforated surface used in this example was TRIFORM C2 wire obtained from Albany International of Portland, Tennessee. The forming wire had the following characteristics: Mesh: 80 x 80 Warp: 0.35 mm polyester Weft: Trainer Side: 0.35 mm Poly Trainer Side: 0.25 mm Cond Medium: 0.35 mm Poly Use Side: 0.40 mm Poly Nominal Caliber: 0.072"Nominal Air Perm: 770 cfm Fabric : Triple stacked plot Nine different non-woven fabrics were produced and tested. Seven of the nine fabrics were produced according to the present invention and contained alternating columns of areas of higher basis weight and areas of lower basis weight that extend in the machine direction.

The low basis weight areas were formed by completely blocking the column sections of the forming wire using an adhesive. Specifically, the following tissues were formed: The control samples listed above, samples 8 and 9, were made according to conventional methods. As shown above, the samples made according to the same pattern, the base weight was varied. The basis weight listed above for the samples made according to the present invention refers to the average weight of the fabric across the width, complete. In general for samples 1 to 7, the basis weight of the upper basis weight areas was 1.7 times greater than the base weight of the lower basis weight areas, which were formed by the wire lock.

Each of the samples listed above were tested for maximum load and maximum power in the machine's transverse direction and in the machine direction. The liquid runoff properties of the tissues were also tested.

The peak load and peak energy measurements of the samples were obtained by carrying out a voltage test on the samples. A stress test is a measure of the resistance to breakage of a fabric when it is subjected to a unidirectional tension. The upper numbers indicate a stronger fabric. The term "load" means the maximum force or load, expressed in units of weight, required to break the sample in a stress test. The term "peak energy" means the total energy under a load against the elongation curve exerted before the break or break.

The liquid runoff test used was the same as described in example 7.

From the tests mentioned above, the following results were obtained.

With respect to the runoff properties of the tested fabrics made according to the present invention compared to the controls (samples numbers 8 and 9) some improvements were observed in some of the tests, but generally the runoff properties between the samples of control and tissues made according to the present invention were similar. Although these results are still favorable, it is believed that no significant improvements in runoff properties are shown because the fabrics were made of small denier filaments, which have a denier of about 2 denier per fiber. At smaller distances, the filaments create less hollow space in the tissue and are not as effective when passing liquids.

In order to compare the resistance data, the following table is provided in order to better compare some of the following information.

As shown above, when comparing the tissues made according to the present invention in relation to the control samples, it was observed that even though the resistance to the tension in the machine direction is somewhat diminished, the resistance in the the transverse direction. This was very unexpected because the sample that was being tested in the direction of the alternating light and heavy areas and the fabric was expected to break and have the properties of the light areas. It is believed that fabrics made in accordance with the present invention have more fiber orientation in the cross machine direction than conventionally made fabrics. Consequently the resistance to the transverse direction is increased. Finally, fabrics made according to the present invention have better overall strength properties in the sense that the resistance in the machine direction is more equal to the resistance in the transverse direction to the machine. In other words, fabrics made according to the present invention have a tendency to have a more uniform strength over the entire area of the fabric.

These and other modifications and variations of the present invention may be practiced by those of skill in the art without departing from the spirit and scope of the present invention which is more particularly set forth in the appended claims. In addition, it should be understood that the aspects of the various incorporations can be interchanged both in whole and in part. In addition, those of ordinary skill in the art will appreciate that the foregoing description is given by way of examples only, and that no attempt is made to limit the invention thus described in the appended claims.

Claims (48)

R E I V I N D I C A C I O N S

1. A nonwoven fabric made of fibers, said nonwoven fabric defines the first areas having a first basis weight and the second areas having a second basis weight are located on said nonwoven fabric according to a predetermined pattern, said first basis weight being greater than said second basis weight, said second areas being configured to pass liquids contacting said areas, said first areas comprise from about 25% to about 75% of said nonwoven fabric.

2. A non-woven fabric, as claimed in clause 1, characterized in that said non-woven fabric comprises a knitted fabric.

3. A non-woven fabric, as claimed in clause 1, characterized in that said first areas and said second areas and said second areas form a repetitive pattern.

4. A non-woven fabric, as claimed in clause 3, characterized in that said first areas and said second areas form alternating columns.

5. A non-woven fabric, as claimed in clause 3, characterized in that said first areas surrounding said second areas, said second areas form discrete shapes.

6. A non-woven fabric, as claimed in clause 3, characterized in that said first areas form alternating rows and alternating columns.

7. A non-woven fabric, as claimed in clause 2, characterized in that said comprise polypropylene fibers.

8. A non-woven fabric, as claimed in clause 1, characterized in that said first basis weight is at least 1.5 times greater than said second basis weight.

9. A non-woven fabric, as claimed in clause 8, characterized in that said first basis weight and said second basis weight are from about 0.2 ounces per square yard to about 9 ounces per square yard.

10. A non-woven fabric, as claimed in clause 1, characterized in that said polymer fibers comprise crimped fibers.

11. A non-woven fabric, as claimed in clause 1, characterized in that said first areas comprise from about 40% to about 60% of said non-woven fabric.

12. A non-woven fabric, as claimed in clause 1, characterized in that said fibers comprise pulp fibers.

13. A non-woven fabric, as claimed in clause 1, characterized in that said fibers comprise polymeric fibers.

14. A non-woven fabric, as claimed in clause 1, characterized in that said non-woven fabric comprises a meltblown fabric.

15. A non-woven fabric, as claimed in clause 1, characterized in that said non-woven fabric comprises a fabric placed by air.

16. A non-woven fabric, as claimed in clause 13, characterized in that said polymeric fibers comprise multicomponent fibers.

17. A process for producing non-woven fabrics having areas of higher basis weight and lower base weight areas, said process comprising the steps of: extruding a thermoplastic polymer through a matrix to form the fibers; directing said fibers to the perforated surface under a suction force, said perforated surface having a predetermined pattern of sections of lower permeability; forming a nonwoven fabric on said perforated surface of said fibers, said fabric defining the first areas having a first basis weight and the second areas having a second basis weight, said first basis weight being greater than said second basis weight, said second ones areas are formed on said second perforated surface where said lower permeability sections are located.

18. A process, as claimed in clause 17, characterized in that it comprises the step of pulling said fibers after said fibers have been extruded.

19. A process, as claimed in clause 17, characterized in that said second areas contained in said fabric are highly permeable to the liquid so that if the tissue were made exclusively from the second areas, said tissue would be configured to pass the liquids that they make contact with said tissue.

20. A process, as claimed in clause 17, characterized in that said thermoplastic polymer comprises polypropylene.

21. A process, as claimed in clause 17, characterized in that said first basis weight and said second basis weight of said non-woven fabric ranges from about 0.2 ounces per square yard to about 9 ounces per square yard.

22. A process, as claimed in clause 21, characterized in that said first basis weight is from about 1.5 to about 5 times more than said second basis weight.

23. A process, as claimed in clause 17, characterized in that said perforated surface is configured to form a non-woven fabric so that said first areas and said second areas form alternating columns.

24. A process, as claimed in clause 17, characterized in that said first areas of said non-woven fabric comprises at least 25% of said fabric.

25. A process, as claimed in clause 24, characterized in that said first areas comprise from about 40% to about 60% of said weave.

26. A process, as claimed in clause 17, characterized in that said fibers comprise bicomponent filaments.

27. A nonwoven fabric comprising extruded polymer fibers, said nonwoven fabric defines the first areas having a first basis weight and the second areas having a second basis weight, said first and second areas being located on the fabric according to a pattern predetermined, said first basis weight being at least 1.5 times greater than said second basis weight, said first basis weight and said second basis weight varying from 0.2 ounces per square yard to 0.9 ounces per square yard.

28. A non-woven fabric, as claimed in clause 27, characterized in that said first basis weight is at least 2 times greater than said second basis weight.

29. A non-woven fabric, as claimed in clause 27, characterized in that said polymer fibers contain a material selected from the group consisting of polypropylene, polyethylene, polyester, nylon, and combinations thereof.

30. A non-woven fabric, as claimed in clause 27, characterized in that said polymer fibers comprise polypropylene.

31. A non-woven fabric, as claimed in clause 27, characterized in that said polymer fibers are crimped.

32. A non-woven fabric, as claimed in clause 27, characterized in that said first areas comprise from about 25% to about 75% of said non-woven fabric.

33. A non-woven fabric, as claimed in clause 27, characterized in that said first areas and said second areas are in alternating columns.

34. A nonwoven fabric, as claimed in clause 27, characterized in that said fabric comprises a melt blown fabric and a yarn bonded fabric.

35. A laminate comprising: a first layer comprising a substrate; Y a non-woven fabric adhered to said substrate, said non-woven fabric comprises pulp fibers or polymer fibers, said non-woven fabric defines the first areas having a first basis weight and the second areas having a second basis weight located on said non-woven fabric; woven according to a predetermined pattern, said first basis weight being at least 1.5 times greater than said second basis weight, said first basis weight and said second basis weight varying from about 0.2 ounces per square yard to about 9 ounces. ounces per square yard.

36. A laminate, as claimed in clause 35, characterized in that said substrate comprises a meltblown fabric.

37. A laminate, as claimed in clause 35, characterized in that said fibers contained within said non-woven fabric comprise polypropylene fibers and wherein said first areas and said second areas form alternating columns.

38. A laminate, as claimed in clause 35, characterized in that said non-woven fabric comprises a spunbonded web. . .

39. A laminate, as claimed in clause 38, further characterized in that it comprises a third layer of non-woven fabric, said non-woven fabric comprises a spunbonded cloth, said first layer being located between the second layer and the third layer.

40. A laminate, as claimed in clause 35, characterized in that said substrate comprises a polymeric film.

41. A laminate, as claimed in clause 35, characterized in that said first layer comprises a non-woven fabric.

42. A diaper that incorporates the laminate defined in clause 35.

43. A cleaning product that incorporates the laminate defined in clause 35.

44. A personal care product that incorporates the laminate defined in clause 35.

45. A laminate, as claimed in clause 35, characterized in that said substrate comprises a meltblown fabric and said nonwoven fabric comprises a yarn bonded fabric.

46. A laminate, as claimed in clause 45, characterized in that said fibers contained within said non-woven fabric comprise bicomponent polymer fibers.

47. A laminate, as claimed in clause 46, characterized in that said bicomponent fibers are crimped.

48. A laminate, as claimed in clause 35, characterized in that said first areas of said non-woven fabric surround said second areas, said second areas form discrete shapes. SUMMARY Non-woven fabrics of differential basis weight of a process for producing the fabrics are described. In particular, the fabrics contain areas of higher basis weight and areas of lower basis weight. For example, in one embodiment, the upper basis weight areas and the lower base weight areas form alternating columns. The fabric may be made according to a spinning process or a melt blowing process using a thermoplastic polymer or an air placed process using pulp fibers. Nonwoven fabrics are particularly well suited for use in diapers and other liquid absorbent products.