MXPA00004657A - Polyethylene oxide thermoplastic composition - Google Patents

Abstract

Disclosed is a thermoplastic composition that comprises an unreacted mixture of polyethylene oxide polymer and a multicarboxylic acid. One embodiment of such a thermoplastic composition is a mixture of polyethylene oxide polymer and adipic acid. The thermoplastic composition is capable of being extruded into fibers that may be formed into nonwoven structures that may be used in a disposable absorbent product intended for the absorption of fluids such as body fluids.

Description

COMPOSITION "BX0PLIS? XC & DB OZZDO DS PQLSSTXLSMO Background of the Invention Field of the Invention The present invention relates to a thermoplastic composition comprising an unreacted mixture of polyethylene oxide and a multicarboxylic acid. The thermoplastic composition is capable of being extruded into fiber which can be formed into non-woven structures which can be used in a disposable absorbent product for the absorption of fluids such as body fluids.

Description of Related Art Disposable absorbent products currently find widespread use in many applications. For example, in the infant and child care areas, diapers and underpants have generally replaceable fabric absorbers for repeated use. Other typical disposable absorbent products include feminine care products such as feminine pads or tampons, adult incontinence products and health care products such as surgical covers or wound dressings. A typical disposable absorbent product generally comprises a composite structure that includes a top sheet and a bottom sheet. These products usually include some type of insurance system to adjust the product to the user.

Disposable absorbent products are typically subject to one or more discharges of liquid, such as water, urine, menstrual fluids or blood during use. As such, the bottom sheet materials of the outer casing of the disposable absorbent products are typically made of insoluble liquid impervious materials and liquids, such as polypropylene films, which exhibit sufficient strength and handling capacity for the absorbent product disposable retain its integrity during use by a user and do not allow the discharge of liquid discharges into the product.

Although current disposable baby diapers and other disposable absorbent products have generally been accepted by the public, these products still need to be improved in specific areas. For example, many disposable absorbent products can be difficult to discard. For example, attempts to discard with water discharge many disposable absorbent products in the toilet down to the drainage system typically lead to the blockage of the toilet or of the pipes connecting the toilet to the drainage system. In particular, the extern cover materials typically used in the disposable absorbent products generally do not disintegrate or disperse when discharged with water discharge through the toilet so the absorbent product can not be disposed of in this way. If the outer cover materials are manufactured very thin in order to reduce the total water absorption of the disposable absorbent product in order to reduce the possibility of blocking the toilet or drainage piping, then the external covering material typically will not be able to exhibit sufficient strength to prevent tearing or tearing as the outer cover material is subjected to normal user stresses.

In addition, the elimination of solid waste is becoming a problem that increases throughout the world. While the fill lands continue to be filled, there has been an increase in the demand for the reduction of the source material of the absorbent products, a demand for the incorporation of more recyclable and / or degradable components in the disposable products and in the design of products. that they can be discarded by other means other than incorporation into solid waste disposal facilities such as landfills.

As such, there is a need for new materials that can be used in disposable absorbent products that generally retain their integrity and resistance during use, but that after such use, said materials can be discarded more efficiently. For example, the disposable absorbent product can be more easily efficiently discarded by composting. Alternatively, the disposable absorbent product can be easily discarded in a liquid drainage system where the absorbent product is capable of being degraded.

Polyethylene oxide is a known material that has been widely used in a variety of applications. However, the processing of polyethylene oxide into a fiber, a film or other non-woven or extrudable structures has proven to be a significant challenge. This challenging task has been found to be particularly difficult when it comes to using polyethylene oxide in a fiber manufacturing process. Such process difficulties are due, in part, to the fact that commercially available polyethylene oxide typically comes in the form of of powder and is predominantly available in high molecular weight versions, typically they are in the range of a weight average molecular weight of over 100,000 8,000,000.

Such physical form or properties of the polyethylene oxide have been found to negatively impact the processing of polyethylene oxide in various forms. First, any material, including polyethylene oxide, in powder form is generally more difficult to process in terms of supply and extrusion as compared to a material in the form of grain, such as is typically found, for example, with polyolefins. Second, the high molecular weight of the polyethylene oxide typically results in a significant entanglement of the polyethylene oxide polymer chains during certain processing techniques, such as extrusion. An extruder that is used in such a situation will typically require a very long torque to deliver the high molecular weight material through which a pronounced "elastic shrinkage" property of the molten fibr which is being processed generally results. It results that the molten fiber is pulled as it leaves the spinning organ adhered to the extruder. These factors generally result in a poor melt strength of the resulting fiber and makes yarn spinning impractical. Third, the polyethylene oxide has a low melt temperature of generally about 65 ° C, which makes the polyethylene oxide difficult to solidify during cooling and which causes process difficulties due to the stickiness of the prepared fiber of the polyethylene. polyethylene oxide.

In addition, the polyethylene oxide is generally a water soluble polymer. As such, even if one were able to prepare the polyethylene oxide fibers, such fibers could have limited use in applications in which the fibers were subject to a discharge of a liquid such as water, urine, blood or the menstruation. Therefore, it will be desirable to be able to make a fiber comprising polyethylene oxide which is not instantaneously soluble to the water but which instead exhibits a delay in the solubility of, for example, water or other aqueous liquids.

It is therefore an object of the present invention to provide a thermoplastic composition comprising polyethylene oxid which exhibits improved procesabilidade properties and desirable solubility properties.

It is also an object of the present invention to provide a thermoplastic composition comprising polyethylene oxide which can be easily and efficiently formed into a fiber.

It is also an object of the present invention to provide a thermoplastic composition comprising polyethylene oxide which is suitable for use in the preparation of non-woven structures.

It is also an object of the present invention to provide a fiber or non-woven structure that is easily degradable in the environment.

Synthesis of the Invention The present invention relates to a thermoplastic composition which is desirably biodegradable and furthermore which can be easily prepared and easily processed into desirable end structures, such as fibers or non-woven structures.

One aspect of the present invention relates to a thermoplastic composition comprising a mixture of a first component and a second component.

An incorporation of such a thermoplastic composition comprises a mixture of a polyethylene oxide and a multicarboxylic acid, wherein the multicarboxylic acid has a total of carbon atoms that is less than about 30, wherein the thermoplastic composition exhibits the desired properties.

In another aspect, the present invention relates to a fiber prepared with the thermoplastic composition wherein the fiber exhibits the thermoplastic properties.

In another aspect, the present invention relates to a non-woven structure comprising a fiber prepared with the thermoplastic composition.

An embodiment of such a non-woven structure and a useful bottom sheet in a disposable absorbent product.

In another aspect, the present invention relates to a disposable absorbent product comprising a non-woven structure comprising in turn a fiber prepared from a thermoplastic composition.

Detailed Description of Preferred Additions The present invention is directed to a thermoplastic composition which includes a first component a second component. As used herein, the term "thermoplastic" is intended to refer to a material that softens when exposed to heat and that generally returns to its original condition when cooled to the ambient temperature.

The first component of the thermoplastic composition is a polyethylene oxide polymer. Suitable polyethylene oxide polymers are known can be obtained, for example, from Union Carbide Corporatio of Danbury, Connecticut.

The polyethylene oxide polymer suitable for use in the present invention is desirably soluble in water. As used herein, a material may be considered as being soluble in water when substantially an excess of water is dissolved to form a solution, so that it loses its initial form and becomes essentially dispersed molecularly through the solution of the solution. Water. As a general rule, water-soluble material may be free to a substantial extent from cross-linking, since cross-linking will provide an insoluble material to water.

As used herein, the term "water-insoluble" is intended to refer to a material that, when exposed to an excess of water, disperses but does not dissolve within a solution.As such, an insoluble material to the water generally it retains its original identity or physical structure, but in a high dispersed state and must have sufficient physical integrity to withstand the flow and fusion with neighboring materials.

It is generally desirable that the polyethylene oxide polymer exhibits a weight average molecular weight that is effective for the thermoplastic composition to exhibit desirable melt strength, fiber strength and fiber spinning properties. In general, if the weight average molecular weight of a polyethylene oxide polymer is very high, this represents that the polymer chains can become heavily entangled which can result in a thermoplastic composition comprising the polyethylene oxide polymer being difficult. to process. Conversely, if the weight average molecular weight of a polyethylene oxide polymer is very low, this means that the polymer chains are not sufficiently entangled which can result in a thermoplastic composition comprising the polyethylene oxide polymer. exhibits a relatively weak fade resistance, making processing at high speed very difficult. Therefore, polyethylene oxide polymers suitable for use in the present invention exhibit a weight average molecular weight that is beneficially between about 10,000 to about 20,000,000, more beneficially between about 150,000 to about 10,000,000, and appropriately enters around 200,000 to around 8,000,000. The weight average molecular weight for polymers or blends of the polymers can be determined using a method as described in the test methods section included herein.

It is generally desirable that the polyethylene oxide polymer be melt processable. It is therefore desirable that the polyethylene oxide polymers used in the present invention exhibit a melt flow rate that is beneficially between about 1 gram per 10 minutes about 600 grams per 10 minutes, appropriately, of about 5 grams per 10 minutes. grams per 10 minutes to about 200 grams per 10 minutes, and more appropriately from 10 grams per 10 minutes to about 150 grams per 10 minutes. The melt flow rate of a material can be determined in accordance with test method ASTM D1238-E, incorporated herein by reference.

It is generally desirable that the polyethylene oxide be present in the thermoplastic composition in an amount effective to result in the thermoplastic composition exhibiting the desired properties. If the polyethylene oxide is present in the thermoplastic composition in a small amount, the thermoplastic composition will generally exhibit poor extrudability processability properties represented for example, by the display of a very low apparent viscosity during processing under conditions, for example, of around 190 &C and a slump rate of about 1000 seconds'1 as well as being very insoluble in, for example, water or other aqueous liquids, thereby limiting the use of such fibers in applications such as absorbent products disposable where the absorbent product is desirable to be disposable with water discharge. In contrast, if the polyethylene oxide is present in the thermoplastic composition in a very large amount, the thermoplastic composition will generally exhibit poor extrudability processability properties represented, for example, by exhibiting a very high apparent viscosity during processing under , for example, of around 190 ° C and a slump rate of about 1000 seconds "1 as well as being very rapidly soluble, for example, in water or other aqueous liquids, thereby limiting the use of such fibers in applications such as the disposable absorbent products.

Therefore, the polyethylene oxide may be present in the thermoplastic composition of the present invention in an amount by weight that is beneficially between about 25 weight percent to about 85 weight percent, more beneficially of about from 30 percent by weight to about 80 percent by weight, and appropriately from about 35 percent by weight to about 75 percent by weight, where all percentages by weight are based on the amount of total weight of the polyethylene oxide and the multicarboxylic acid present in the thermoplastic composition.

The second component of the thermoplastic composition is a multicarboxylic acid. A "multi-carboxylic acid" is any acid that comprises two or more carboxylic acid groups. The dicarboxylic acids are those suitable for use in the present invention, which comprise two carboxylic acid groups. It is generally desirable that the multicarboxylic acid have a total number of carbons that is not very long because then the multicarboxylic acid can interfere negatively in the processing of the thermoplastic composition. It is therefore desirable that the multicarboxylic acid have a total carbon atom that is beneficially less than about 30, more beneficially between about 3 to about 30, appropriately between about 4 to about 20, and more Appropriately from 5 to about 10. Appropriately multi-carboxylic acids include, but are not limited to malonic acid, citric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid , the sebacic acid and mixtures thereof.

Suitable multi-carboxylic acids for use in the present invention are generally soluble in water but generally exhibit a solubility that is relatively slower than that exhibited by polyethylene oxide. As such, the addition of the multicarboxylic acid to a polyethylene oxide generally reduces or slows the water solubility of the total mixture.

It is generally desirable that the multi-carboxylic acid be present in the thermoplastic composition in an amount effective to result in the tremoplastic composition exhibiting the desired properties. If the multicarboxylic acid is present in the thermoplastic composition in a very small amount, the thermoplastic composition will generally be able to exhibit poor extrudability processability properties represented, for example, by exhibiting a very high apparent viscosity during processing under conditions, for example, of about 190 ° c and a slump rate of about 1000 seconds'1 as well as being rapidly soluble, for example, in water or other aqueous liquids, whereby the use of such fibers is limited to applications such as in absorbent products disposable. In contrast, if the polyethylene oxide is present in the thermoplastic composition in a much larger amount, the thermoplastic composition will generally be able to exhibit poor extrudability processability properties represented, for example, by exhibiting a very low apparent viscosity during processing under conditions, for example, around 190 ° C and a slump rate of about 1000 seconds' 1 as well as being insoluble in, for example, water or other aqueous liquids, whereby the use of such fibers is limited to applications such as the disposable absorbent products where the disposable absorbent product is desirable to be disposable with water discharge.

Therefore, the carboxylic acid may be present in the thermoplastic composition in an amount by weight that is beneficially between about 15 weight percent to about 75 weight percent, more beneficially between about 20 weight percent. by weight to about 70 percent by weight, and more appropriately from 25 percent by weight to about 65 percent by weight, where all percentages by weight are based on the total amount of weight of the oxide polymer. of polyethylene and the carboxylic acid present in the thermoplastic composition.

In the present invention, it is generally desirable that both the polyethylene oxide polymer and the multicarboxylic acid be biodegradable. As a result, the thermoplastic composition comprises the polyethylene oxide polymer and the multicarboxylic acid, either in the form of a fiber or in the form of a non-woven structure, may be degradable when discarded in the environment and exposed to air. and / or to water. As used herein, "biodegradable" is intended to represent that a material is degraded by the action of naturally occurring microorganisms such as bacteria, fungi, and algae.

In the present invention, it is also desirable that the polyethylene oxide polymer and the multicarboxylic acid be compounds. As a result of this, the thermoplastic composition comprising the polyethylene oxide polymer and the multicarboxylic acid, either in the form of a fiber or in the form of a non-woven structure, may be compostable when disposed in the environment and expose to air and / or water. As used herein, "compostable" is intended to represent that the material is capable of undergoing biological decomposition at a composite site such that the material is not visually distinguishable and breaks down into carbon dioxide, water, inorganic compounds and biomass. at a tas consistent with known compostable materials.

While the main components of the thermoplastic composition of the present invention have been described in the foregoing, such a thermoplastic composition is not limited thereto and may include other components that adversely affect the desired properties of the thermoplastic composition. The sample materials which may be used as additional components may include, without limitation, pigments, antioxidants, stabilizers, the surfactants, the waxes, the flow promoters, the solid solvents, the plasticizers, the nucleated agents, the particles and the aggregated materials to increase the processability of the thermoplastic composition. If such thermoplastic components are included in a thermoplastic composition, it is generally desirable that such additional components be used in an amount that is beneficially less than about 5 percent by weight, more beneficially less than about 3 percent by weight and more. Approximately less than about 1 percent by weight, wherein all percentages are based on the total weight amount of polyethylene oxide polymer, of the multi-carboxylic acid, of the additional components present in the thermoplastic composition.

The thermoplastic composition of the present invention is simply a mixture of the polyethylene oxide polymer, the multicarboxylic acid, and, optionally, any additional components. In order to achieve the desired properties of the thermoplastic composition of the • present invention, it has been found to be critical that the polyethylene oxide polymer and the multicarboxylic acid remain substantially unreacted with each other so that a copolymer comprising each of the polymers of polyethylene oxide and the multicarboxylic acid is not formed. As such, each of the polymers of polyethylene oxide and multicarboxylic acid remain as separate components of the thermoplastic composition. In order to determine whether the polyethylene oxide polymer and the multicarboxylic acid remains essentially unreacted, it is possible to use techniques, such as nuclear magnetic resonance and infrared analysis, to evaluate the chemical characteristics of the final thermoplastic composition.

Each of the polyethylene oxide polymers and the multicarboxylic acid may generally form separate regions or domains within a prepared mixture forming the thermoplastic composition. However, depending on the relative amounts that are used of each of the polyethylene oxide polymer and the multicarboxylic acid, an essentially continuous phase of a material that is present in the thermoplastic composition in a relatively larger amount can be formed. In contrast, the material that is present in the thermoplastic composition in a relatively minor amount can form an essentially discontinuous phase, forming separate regions or domains within the continuous phase which substantially pigeonhole the less general material within the structure. As used herein, the term "pigeonholing," and related terms, are intended to mean that the more general material of continuous phase substantially encloses surrounds less general materials in separate regions domains.

In the thermoplastic composition of the present invention, the multicarboxylic acid is believed to perform at least one important function. When the thermoplastic composition is in a molten state, the multicarboxylic acid is believed to function as a process lubricant or plasticizer that facilitates the processing of the thermoplastic composition while increasing the flexibility and firmness of a final product, such as a fiber. or a non-woven structure through an internal modification of the polyethylene oxide polymer. Even when no attempt is made to be bound by this, it is believed that the multicarboxylic acid replaces the secondary d-bonds that hold the polyethylene oxide polymer chains together with the multicarbixilic acid with polyethylene oxide polymer valency bonds. both facilitating the movement of the polymer chain segments of polyethylene oxide. This effect is evidenced, for example, because an extrusion temperature can generally be used to process the thermoplastic composition comprising both the polyethylene oxide polymer and the multicarboxylic acid in comparison with the processing of the polyethylene oxide polymer alone. With this effect, the force required to rotate an extruder is generally dramatically reduced as compared to the polymer processing of polyethylene oxide alone.

In an embodiment of the present invention, after dry blending of the polyethylene oxide polymer and the multicarboxylic acid together to form a dry blend thermoplastic composition, such a dry blend thermoplastic composition is beneficially stirred, stirred or otherwise intermixed to effectively mixing uniformly polyethylene oxide polymer and multicarboxylic acid d such that a dry mixture is essentially homogeneous. The dry mixture can then be melted, for example, in an extruder to effectively mix uniformly the polyethylene oxide polymer and the multicarboxylic acid in such a way that an essentially homogeneous melt mixture is formed. The essentially molten and homogeneous mixture can then be cooled and formed into pellets. Alternatively, the homogeneously molten mixture may be sent directly to a spin pack or other equipment to form fibers or a non-woven structure. Other methods for mixing together the components of the present invention are also possible and will be easily recognized by a skill in the art.

The process of cooling the extruded thermoplastic composition to room temperature is usually achieved by blowing air at ambient ambient temperature onto the extruded polymer. This can be mentioned as cooling or supercooling because the change in temperature is usually higher than 100 ° C and very often higher than 150 ° C in a relatively short time frame (seconds).

It is generally desirable that the melting or softening temperatures of the thermoplastic composition be within the ranges that are typically found in most process applications. As such, it is generally desired that the melting or softening temperatures of the thermoplastic composition be beneficially between about 25ac to about 350 amp, more benignly between about 50 amp to about 300 sc and more appropriately around 60ac to around 200 &C.

The thermoplastic composition of the present invention has been found to generally exhibit improved processability properties compared to a thermoplastic composition comprising the polyethylene oxide polymer but none of the multicarboxylic acid. As used herein, the improved processing of a thermoplastic composition is measured as a decrease in the apparent viscosity of the thermoplastic composition at a temperature of about 190ac and a shear rate of about 1000 seconds, typically the processability and extrusion conditions. industrial. If the thermoplastic composition exhibits an apparent viscosity that is very high, the thermoplastic composition will generally be very difficult to process. In contrast, if the thermoplastic composition exhibits an apparent viscosity that is very low, the thermoplastic composition may generally result in an extruded fiber having a very low tensile strength.

Therefore, it is generally desirable that the thermoplastic composition exhibit an apparent viscosity value at a temperature of about 190 ° C and a shear rate of about 1000 seconds'1 which is beneficially about 5 Pascal seconds (Pa. s) to about 25 Pascal seconds, more beneficially from about 1 Seconds Pascals to about 225 Seconds Pascals appropriately from about 15 Pascal seconds to about 200 Seconds Pascal, more appropriately from about 20 Seconds Pascals to about 190 second Pascal, and more appropriately between about 25 second Pascal to about 180 Pascal seconds. The method by which the apparent viscosity value is determined is set forth below in connection with the examples.

As used herein, the term "fiber" or "fibrous" means that it refers to a material wherein the ratio d the length to the diameter of such a material is greater than about d 10. Conversely, a "non-fiber" material or "non-fibrous" means that it refers to a material in which the proportion of the length to the diameter of such material is about 10 less.

The methods for manufacturing the fibers are known and do not need to be described in detail here. To form a fiber, generally, a thermoplastic composition extruded and fed into a distribution system where the thermoplastic composition is introduced into a spinning organ planch. The spun fiber is then cooled, solidified and pulled, generally by a mechanical roller system, to an intermediate filament diameter and collected. Subsequently, the fiber can be "cold drawn" at a temperature below its softening temperature, to the desired finished fiber diameter and is curled / textured cut to a desired fiber length. The fibers can be cut into relatively short lengths, such as the basic fibers which generally have lengths in the range d about 25 millimeters to about 50 millimeters and the short staple fibers are even shorter and generally have lengths of less than about of 18 millimeters.

Typical conditions for thermally processing the thermoplastic composition include using a casting rate that is beneficially between about 100 seconds1 to about 50,000 seconds1, more beneficially between about 500 seconds'1 to about 5000 seconds-1, appropriately from 1000 seconds' to about 3000 seconds1, and more preferably around 1000 seconds'1. Typical conditions for thermally processing the components also include using a temperature which is beneficially between about 100 ° C to about 500 ° C, more beneficially between about 150 ° C to about 300 ° C, appropriately between about 175 ° C to around 250ßC, and appropriately around 190flC.

The thermoplastic composition of the present invention is suitable for preparing fibers or non-woven structures that can be used in disposable products including disposable absorbent products such as diapers, adult incontinence products and bed pads; in catamenial devices such as sanitary napkins and plugs; and other absorbent products such as cleansing cloths, bibs, wound dressings and surgical covers. Accordingly, in another aspect, the present invention relates to an absorbent product comprising the fibers prepared with the thermoplastic composition of the present invention.

When used in a disposable absorbent product, it is generally desirable that the fiber prepared from the thermoplastic composition of the present invention be hydrophilic. As used herein, the term "hydrophilic" refers to a material that has a contact angle with the agu in air of less than 90 degrees. In contrast, as used herein, the term "hydrophobic" refers to a material having a contact angle of water in air of at least 90 degrees. The general subject of contact angles and the measurements of them is well known in art as, for example, by Robert J. Goo and Robert J. Stromberg, Ed, in "Surface and Science Colloid Experimental Methods", Vol II, (Plenum Press, 1979).

In an embodiment of the present invention, the thermoplastic composition is formed into a multi-component fiber. For purposes of illustration only, the present invention may generally be described in terms of a multi-component fiber comprising only three components. However, it should be understood that the scope of the present invention involves including fibers with three or more components. In one embodiment, the thermoplastic composition of the present invention can be used to form a sheath of a multi-component fiber while a polyolefin, such as polypropylene or polyethylene is used to form a core. Suitable structural geometries for multi-component fibers include cake-shaped or side-by-side configurations.

When the thermoplastic composition of the present invention is formed into a multi-component fiber, a surface exposed in at least a portion of the multi-component fiber will typically be formed of the most prevalent material present in the multi-component fiber. Such an exposed surface on at least a portion of the multi-component fiber which may generally allow thermal bonding of the multi-component fiber to other fibers which may be the same as or different from the multi-component fibers of the present invention . As a result of this, the multi-component fiber can then be used to form thermally bonded fibrous non-woven structures such as a non-woven fabric.

In one embodiment of the present invention, the thermoplastic composition is formed in a fibrous binder for incorporation into a disposable absorbent product. A fibrous binder can take. the way of, for example, a fibrous non-woven fabric. The fibrous non-woven fabrics can be manufactured entirely from fibers prepared from the thermoplastic composition of the present invention or can be mixed with other fibers. The length of the fibers used may depend on the particular end use contemplated. Where the fibers must be degraded in water as, for example, in a toilet, it will be advantageous if the lengths are maintained at or below about 15 millimeters.

The thermoplastic composition can also be used as a coating or co-extrudate component of a disposable film with water discharge for applications in composite fabric-type outer covers for discharging diapers with water discharge, or as a deflecting barrier film for care towels feminine and for incontinence products for adults. This thermoplastic composition can also be used in cast film or blown film applications.

In an embodiment of the present invention, provided a disposable absorbent product, whose disposable absorbent product comprises a liquid permeable upper sheet, a lower sheet adhered to the liquid permeable upper sheet, and an absorbent structure positioned between the liquid-permeable upper sheet and the lower sheet, wherein the lower sheet comprises fibers prepared from the thermoplastic composition of the present invention.

Absorbent products and structures in accordance with all aspects of the present invention are generally subject, during use, to the multiple discharge of a liquid body. Accordingly, the absorbent products and structures are desirably capable of absorbing multiple discharges of body liquids in quantity to which absorbent products and structures may be exposed during use. The downloads are generally separated from each other for a period of time.

Test Procedures Apparent Viscosity A capillary rheometer, under the designation Gottfer Rheograph 2003 capillary rheometer, which was used in combination with the WinRHEO analysis software (version 2.31), both available from the Gottfert Company of Rock Hill, South Carolina, used to evaluate the rheological properties of Apparent viscosity of material samples. The organization of capillary rheometry included a 2000 bar pressure transducer and a round hole capillary die, 30 mm long / 30 mm active larg / 1 mm diameter / 0 mm height / line run at an angle.

Once the instrument has been heated the pressure of the transducer is calibrated, the material sample is incrementally loaded into the column, resin is packed inside the column with one loader at a time to ensure a consistent melt during the test. After loading the material sample, a time of 2 minutes precedes each test to allow the material sample to fully melt at the test temperature. The capillary rheometer automatically takes information points and determines the apparent viscosity (in Pascal seconds) at 7 apparent tundid rates (in second "1): 50, 100, 200, 500, 1000, 2000 and 5000 When the resulting curve is examined It is important that the curv be relatively smooth.If there are significant deviations from a general curve from one point to another, possibly due to air in the column, the test run should be repeated to confirm the results.

The rheological curve resulting from the apparent flow rate against the apparent viscosity gives an indication of how the material sample can be run at a temperature in an extruder process. The value of the apparent viscosity at a melt rate of about 1000 seconds-1 a temperature of about 190ac is of specific interest because these are typical conditions found in commercial fiber spinning extruders.

Weight average molecular weight A gas permeable gas chromatography (GP) method can be used to determine the weight average molecular weight of the polyethylene oxide samples.

A differential refractometer, available Viscotek Corporation under the designation Knauer Differentia Refractometer with a Viscotek Differential Viscoater, Model 100, is armed with two linear ga permeable gas chromatographic columns, 120 Angstrom Waters Ultrahydrogel that have a flow rate of about 1.0 milliliters per minute and a volume of injection of 100 microliters. The mobile phase is an aqueous 0.05M sodium nitrate solution. The mobile phase is filtered with a 0.45 micron filter and is degassed using a vacuum and an ultrasound bath. The polyethylene oxide criteria are obtained by having distributions of narrow molecular weights with known peaks of average molecular weight and intrinsic viscosity values.

Samples of both criteria of the polyethylene oxides and the experimental polyethylene oxide materials are prepared by dissolving about 1 milligram to 25 milligrams (weighed to the nearest 0.0001 gram of a polyethylene oxide material in about 20 milliliters of The mobile phase solution in a clear flash borosilicate flask Each experimental criterion and sample is chromotographed three times in order to ensure the reproduction of the results and to protect against any unexpected instrumental disorder.The information is collected and calculated using the Unical GPC software, version 4.03 available from Viscotek Corporation of Houston, Texas, and the software manual describes in detail all the formulas algorithms and spiral integrals used for the calculations For each sample, the average molecular weight d is obtained.

To confirm that the instrument is operating correctly, a number is made of verifications. The differential refractometer should have a reading of 3. millivolts in the output detector, differential transducers in the viscometer should be placed close to zero and the backup pressure system should have a reading below 1000 pounds per square inch. . A normal pic of low molecular weight dispersed mono should be symmetrical and the total number of plates should be above 16,000 plates / bank.

Dispersability to Asu / Dissolution of a Fiber The evaluation of the water dispersability / dissolution of a fiber sample was done by immersing the fiber of about 300 microns in diameter and a length of about 5 centimeters into a 100 milliliter beaker containing water current at around 18ac by examining the degree of fiber disintegration and its dissolution over time. For a sample that dissolves or disintegrates into pieces smaller than 1 millimeter within 10 minutes at the beginning of the test, the sample tested was defined as having an "instantaneous" dispersibility. For a sample that dissolves or disintegrates into pieces smaller than 2 millimeters beyond 10 minutes but in less than 2 hours, the sample tested was referred to as having a "delayed" dispersibility. For a sample that dissolves or disintegrates into pieces smaller than 2 millimeters beyond 2 hours, the sample was defined as "slow" dispersibility.

EXAMPLES Example 1 A polyethylene oxide was obtained from Unio Carbide Corporation of Danbury, Connecticut, under the designation polyethylene oxide POLYOX * WSRN-80, which has a melting temperature of about 6 ßc, a melt flow of about 190 & C and 21.6 kilograms of between 25 35 grams per minute, and an average molecular weight of reported pes of about 200,000. This polyethylene oxide was used in samples 1, 2 and 4 to 13.

A polyethylene oxide was obtained from Unio Carbide Corporation of Danbury, Connecticut, under the designation polyethylene oxide POLYOX »WSRN-750, which has a melt flow of about 190ac and 21.6 kilograms of between 3 to grams per minute and a average molecular weight of measured weight d around 458,000. This polyethylene oxide was used in samples 3.

The polyethylene oxide polymer was mixed with various amounts of additives, including both multi-carboxylic acids or other materials. Adipic acid was used as the multicarboxylic acid in samples 3 to 7 and 9 to 13. Glutaric acid was used as the multicarboxylic acid in sample 8. In sample 2, kaolin, an aluminum silicate with a specific gravity of about 2.63 and an average particle size of about 0.5 microns, available from Burgesß Pigment Co. of Sandersville, Georgia, under the designation Polyclay aluminum silicate was used as a typical nucleating agent. In samples 5, 7 and 10, 3 weight percent of 3,5-di-t-butyl-hydroxyltoluene (identified in Table 1 with BHT) available from Shell Chemical Co. of Houston, Texas, under the designation IONOL ™ 3,5-di-t-butyl-hydroxyltoluene was added to the mixture as an antioxidant.

The mixing of the polyethylene oxide polymer with the additives involved the dry mixing of the components followed by mixing to melt them together to provide a vigorous mixing of the components, which was achieved in a twin screw counter-rotary extruder. The mixing was conducted in either a twin screw mixer Brabender or a twin screw extruder Haake with mixer screws.

The conversion of the prepared mixtures into fibers was conducted on an inner fiber spinning line. The spinning line consists of a 0.75 inch diameter extruder with a 24: 1 L: D ratio (length, diameter) of screw and 3 heating zones which feed in a spinning pump, through a unit of static mix Koch »SMX of 0.62 inches and then to a spinning head (representing the fourth and fifth heating zones), from which the fibers are spun through a spinner organ with 15 holes, where each hole has a diameter 20 mm. The fibers were cooled with air at 15 ° C and pulled down with a mechanical pull roller where the fiber was either formed in a non-woven or was collected for further processing (such as pleating and cutting the fiber for production of basic fibers and short-cut fibers) before they are formed into a nonwoven. The composition, the temperature profile process conditions, the evaluations of the apparent viscosity values and the water dispersibility and the comments on the processability of the prepared fibers are shown in Table 1.

ZABJU Example 2 A mixture of polyethylene oxide of Unio Carbide POLYOX »SN80 and of adipic acid in a proportion d 40; 60 was composed with a twin screw extruder. The bicomponent fibers with either a proportion structure by weight of extruder production of 1: 1 core to sheath or a ratio structure but extruder production of 1: 5 d core to sheath were prepared by using this composition Thermoplastic material such as Himont PF305 sheath and polypropylene material as the core material. The hilad was made on a bicomponent spinning line using identical extruders, which have identifiable specifications in the monocomponent fiber section, feeding the bicomponent sheath / core spinning pack and spinning through 16 holes of 12 millimeters in diameter . The temperature profile of the extruder for the sheath in the five different zones is 150ßc / 155dC / 160ac / 165flC / 1700C and the tempreratur of the extruder for the core in the five different zones is d 150ac / l66fiC / 175fiC / 190fiC / 190ac. In the same way, the fiber was cooled at 15 &C and pulled down to where it was either formed into a non-woven fabric or collected for further processing (such as curling and cutting for basic and short-cut fiber production). ) before being formed into a nonwoven. The processability of the fiber was significant due to the improved melt strength and melt flow properties, as evidenced by a significantly improved maximal jet stretch (maximum jet stretch d 295 for the core / sheath ratio of 1: 1 and a maximum jet stretch of 0 for control), reduced tack and was less hygroscopic compared to fibers made with 100 percent by weight of polyethylene oxide and other comparative examples. The lower sensitivity to moisture and reduced adhesive properties make the fiber much easier to handle during the process.

Those skilled in the art will recognize that the present invention is capable of many modifications without departing from the scope thereof. Accordingly, the detailed description and examples set forth above are mentioned to be illustrative only and are not intended to limit, in any way, the scope of the invention as set forth in the appended claims.

Claims (27)

1. MIYIMPICACIOMlff 1. An oplastic tßr composition comprising a mixture of: a polyethylene oxide polymer having a weight average molecular weight that is between about 100,000 and about 20,000,000 where the polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 2 per cent. percent by weight to around 85 per cent of weight; Y a multicarboxylic acid having a total d carbon atoms that is less than about d 30, wherein the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 15 weight percent to about 75 weight percent. weight percent, wherein all percentages by weight are based on the total weight amount of the polyethylene oxide and the multicarboxylic acid present in the thermoplastic composition; wherein the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 190 ° C and a shear rate of about 1000 seconds which is between about 5 Pascal seconds to about 25 Pascal seconds.
2. 2. The thermoplastic composition as claimed in clause 1, characterized in that the polyethylene oxide polymer has a weight average molecular weight u is between about 150,000 to about 10,000,000.
3. 3. The thermoplastic composition as claimed in clause 1, characterized in that the multicarboxylic acid has a total of carbon atoms that is between about 3 to about 30.
4. 4. The thermoplastic composition as claimed in clause 1, characterized in that the multicarboxylic acid is selected from a group consisting of malonic acid, citric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and mixtures thereof.
5. 5. The thermoplastic composition as claimed in clause 1, characterized in that the polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 30 weight percent to about 80 weight percent the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 20 weight percent to about 70 weight percent.
6. 6. The thermoplastic composition as claimed in clause 1, characterized in that the polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 35 weight percent to about 75 weight percent. weight and the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 25 weight percent to about 65 weight percent.
7. 7. The thermoplastic composition as claimed in clause 1, characterized in that the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 190ac and at a ripping rate of about 1000 seconds "1 which is between about 10 seconds Pascals to around 225 Pascal seconds.
8. 8. The thermoplastic composition as claimed in clause 7, characterized in that the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 190ac and a shear rate of about 1000 seconds'1 which is between 15 seconds Pascals around 200 Pascal seconds.
9. 9. The thermoplastic composition as claimed in clause 1, characterized in that the polyethylene oxide polymer has a weight average molecular weight is between about 150,000 to about 10,000,000 and polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 30 weight percent to about 80 weight percent by weight the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between 20 weight percent to about 70 weight percent and selected from a group consisting of malonic acidCitric Acid, Succinic Acid, Glutaric Acid, Adipic Acid, Acidic Acid, Subreic Acid, Azelaic Acid, Sebacic Acid mixtures thereof, and the thermoplastic composition exhibits apparent viscosity value at a temperature of about 19oac and at a set rate. of about 1000 seconds "1 q is between about 10 seconds Pascals to about 2 Pascal seconds.
10. 10. A fiber prepared from a thermoplastic composition, the thermoplastic composition comprises a mixture of: to. a polyethylene oxide polymer having weight average molecular weight that is between about 100,000 to about 20,000,000, wherein the polyethylene oxide polymer is present in the thermoplastic composition in a weight amount that is between about 25 one hundred to about 85 percent; Y a multicarboxylic acid having a total of carbon atoms that is less than about 30, wherein the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 15 weight percent to about 75 weight percent. percent by weight, wherein all percentages by weight are based on the total amount of polyethylene oxide and multicarboxylic acid present in the thermoplastic composition; wherein the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 190ac and at a tundid rate of about 1000 seconds'1 which is between about 5 Pascal seconds to about 250 Pascal seconds.
11. 11. The fiber as claimed in clause 10, characterized in that the polyethylene oxide polymer has a weight average molecular weight that is between about 150,000 to about 10,000,000.
12. 12. The fiber as claimed in clause 10, characterized in that the multicarboxylic acid has a total of carbon atoms that is between about 3 about 30.
13. 13. The fiber as claimed in clause 10, characterized in that the multicarboxylic acid is selected from a group consisting of malonic acid, citric acid, succinic acid, glutaric acid, adipic acid, acid pimelic, superaric acid, azelaic acid, acid sebacic mixtures thereof.
14. 14. The fibers as claimed in clause 10, characterized in that the polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 30 weight percent to about 80 weight percent and the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 20 weight percent to about 70 weight percent.
15. 15. The fiber as claimed in clause 14, characterized in that the polyethylene oxide polymer is present in the thermoplastic composition in a quantity by weight that is between about 35 weight percent to about 75 weight percent and the multicarboxylic acid is present in the thermoplastic composition a weight amount that is between about 25 percent by weight to about 65 percent by weight.
16. 16. The fiber as claimed in clause 10, characterized in that the thermoplastic composition exhibits an apparent viscosity value at a temperature d around 190 bc and at a slump rate of about 100 seconds "1 which is between about 10 seconds Pascals around of 225 Pascal seconds.
17. 17. The fiber as claimed in clause 16, characterized in that the thermoplastic composition exhibits an apparent viscosity value at a temperature d around 190ac and at a shear rate of about 100 seconds "1 which is between about 15 seconds Pascals around 200 Pascal seconds.
18. 18. The fiber as claimed in clause 10, characterized in that the polyethylene oxide polymer has a weight average molecular weight that is between about 150,000 to about 10,000,000 and polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 30 weight percent to about 80 weight percent the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 20 weight percent to about 70 percent per pes and is selected from a group consisting of malonic acid citric acidsuccinic acid, glutaric acid, pimelic acid adipic acid, subaraic acid, azelaic acid, sebacic acid mixtures thereof, and the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 190 ° C and at a settling rate of about 1000 seconds-1 qu is between about 10 seconds Pascals to about 22 Pascal seconds.
19. 19. A disposable absorbent product comprising a liquid-permeable topsheet, a lower blade attached to the liquid-permeable topsheet, and an absorbent structure positioned between the liquid-permeable topsheet and the bottomsheet, wherein the bottomsheet comprises the prepared fibers. of a thermoplastic composition comprising a mixture of: to. a polyethylene oxide polymer having a weight average molecular weight that is between about 100,000 to about 20,000,000, wherein the polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 2. percent by weight of about 85 per cent by weight; Y a multicarboxylic acid having a total carbon atoms that is less than about 30 d, wherein the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 1 weight percent to about 75 weight percent. scientific by weight, where all percentages per pes are based on the total amount per pes of the polyethylene oxide and the multicarboxylic acid present in the thermoplastic composition; wherein the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 190ac and at a slump rate of about 1000 seconds-1 which is between about 5 Pascal seconds to about 250 Pascal seconds.
20. 20. The disposable absorbent product as claimed in clause 19, characterized in that the polyethylene oxide polymer has an average molecular weight of pe that is between about 150,000 to about 10,000,000.
21. 21. The disposable absorbent product such and co is claimed in clause 19, characterized in that the multicarboxylic acid has a total of carbon atoms that is between about 3 to about 30.
22. 22. The deductible absorbent product as claimed in clause 19, characterized in that the multicarboxylic acid is selected from a group consisting of malonic acid, citric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, azelaic acid, sebacic and mixtures thereof.
23. 23. The disposable absorbent product as claimed in clause 19, characterized in that the polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is between about 30 percent by weight of about 80 percent by weight. and the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 20 percent to about 70 percent by weight
24. 24. The disposable absorbent product as claimed in clause 23, characterized in that the polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight ranging from about 35 weight percent to about 75 weight percent. per pe and the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 25 weight percent to about 65 weight percent.
25. 25. The disposable absorbent product as claimed in clause 19, characterized in that the thermoplastic composition exhibits a viscosity value appearing at a temperature of about 190ac and at a tundid rate of about 1000 seconds-1 which is between about 100.degree. 1 seconds Pascals to around 225 Pascal seconds.
26. 26. The disposable absorbent product as claimed in clause 25, characterized in that the thermoplastic composition exhibits a viscosity value appearing at a temperature of about 190ac and at a tundid rate of about 1000 seconds'1 which is between about 1. Pascal seconds to around 200 Pascal seconds.
27. 27. The disposable absorbent product as claimed in clause 19, characterized in that the polyethylene oxide polymer has an average molecular weight of weight ranging from about 150,000 to about 10,000,000 polyethylene oxide polymer is present in the thermoplastic composition in an amount by weight that is about 30 per cent. per cent by weight to about 80 per cent by weight, the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 20 weight percent to about 70 per cent and is selected from a group consisting of of malonic acid, citric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superaric acid, azelaic acid, sebacic acid mixtures thereof, and the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 190 ° C and at a sputtering rate of about 1000 seconds-1 which is between about 10 Pascal seconds to about 2 25 seconds Pascals. A thermoplastic composition comprising an unreacted mixture of a polyethylene oxide polymer and a multicarboxylic acid is described. An incorporation of such a thermoplastic composition is a mixture of polyethylene oxide and adipic acid polymer. The thermoplastic composition is capable of being extruded into fibers that can be formed into non-woven structures that can be used in a disposable absorbent product designed for the absorption of fluid such as body fluids.