MXPA01001075A

MXPA01001075A - Biodegradable thermoplastic polyester composition with improved wettability

Info

Publication number: MXPA01001075A
Application number: MXPA/A/2001/001075A
Authority: MX
Inventors: Fujya Tsai; Brigitte C Wertheim
Original assignee: Kimberlyclark Worldwide Inc
Priority date: 1998-08-31
Filing date: 2001-01-29
Publication date: 2001-11-21

Abstract

A thermoplastic composition that comprises an unreacted mixture of an aliphatic polyester polymer selected from the group consisting of a polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers;a multicarboxylic acid;and a wetting agent. 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

BIODEGRADABLE THERMOPLASTIC COMPOSITION WITH IMPROVED HUMECTABILITY Background of the Invention The present invention relates to a thermoplastic composition comprising an unreacted mixture of an aliphatic polyester polymer selected from the group consisting of polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixing of such polymers, or a copolymer of such polymers; a polycylboxic acid; and a wetting agent. 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 intended 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 infant and child care areas, diapers and training underpants have generally replaced reusable fabric absorbent articles. Other typical disposable absorbent products include women's care products such as sanitary napkins or tampons, adult incontinence products, and health care products such as wound dressings and surgical covers. . A typical disposable absorbent product generally comprises a composite structure including an upper sheet, a lower sheet, and an absorbent structure between the upper sheet and the lower sheet. These products usually include some type of fastener system > to adjust the product on the user.

Disposable absorbent products are typically subjected 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 cover of the disposable absorbent products are typically made of liquid insoluble and liquid impervious materials, such as polypropylene films, which exhibit sufficient strength and handling capacity so that the Disposable absorbent product retains its integrity during use by a user and does not allow the runoff of the liquid discharged into the product.

Even though current disposable baby diapers and other disposable absorbent products have generally been accepted by the public, these products will need improvements in specific areas. For example, disposable absorbent products may be difficult to dispose of. For example, attempts to discard water from many disposable absorbent products in a toilet inside the sewer system typically leads to the blockage of the toilet or the pipes connecting the toilet to the sewer system. In particular, the outer cover materials are typically used in disposable absorbent products generally do not disintegrate or disperse when disposed of with flushing in a toilet so that the disposable absorbent product can not be discarded in this manner. If the outer cover materials are made too thin in order to reduce the overall volume of the disposable absorbent product to reduce the possibility of blocking a toilet or sewer pipe, then the outer cover material will typically not exhibit sufficient strength. to avoid tearing or ripping when the outer covering material is subjected to the stresses of normal use by a user.

In addition, the waste of solid waste has become an increasing concern throughout the world. As filling sites continue to fill, there has been an increased demand for a reduction in the source of material in disposable products, the incorporation of more recyclable and / or degradable components into disposable products, and the design of products that can be disposed of. means other than incorporation in solid waste disposal facilities such as filling grounds.

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

Many of the commercially available biodegradable polymers are aliphatic polyester materials. Although the fibers prepared from aliphatic polyesters are known, problems have been encountered with their use. In particular, aliphatic polyester polymers are known to have a relatively slow crystallization rate compared to, for example, polyolefin polymers, often resulting in poor processability of the aliphatic polyester polymers. Most aliphatic polyester polymers also have much lower melting temperatures than polyolefins and are difficult to sufficiently cool after thermal processing. Aliphatic polyester polymers are, in general, inherently non-wettable materials and may require modifications for use in a personal care application. In addition, the use of processing additives may retard the rate of biodegradation of the original material or the processing additives themselves may not be biodegradable.

Synthesis of the Invention The present invention relates to a thermoplastic composition that is desirably biodegradable and yet which is easily prepared and easily processable in desired end structures, such as non-woven or fiber structures.

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

An incorporation of such a thermoplastic composition comprises a blend of an aliphatic polyester polymer selected from the group consisting of a polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers; a multi-carboxylic acid wherein the poly-carboxylic acid has a total of carbon atoms that is less than about 20; and a wetting agent which exhibits a hydrophilic-lipophilic balance ratio that is between about 10 to about 40, wherein the thermoplastic composition exhibits the desired properties.

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

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

One embodiment of such a non-woven structure is a lower sheet useful in a disposable absorbent product.

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

It has been discovered that, by using an unreacted mixture of the components described herein, a thermoplastic composition can be prepared wherein such a thermoplastic composition is essentially degradable but whose thermoplastic composition is easily processed into fibers and non-woven structures exhibiting fibrous mechanical properties efective.s.

The first component in the thermoplastic composition is an aliphatic polyester polymer selected from the group consisting of a polybutylene succinate C 'polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers.

A polymer of polybutylene succinate is generally prepared by the condensation polymerization of a glycol and a dicarboxylic acid or acid anhydride thereof. A polybutylene succinate polymer can be either a linear polymer or a long chain branched polymer. A long chain branched polybutylene succinate polymer is generally prepared by the use of an additional polyfunctional component selected from the group consisting of trifunctional or tetrafunctional polyols, oxycarboxylic acids, and polybasic carboxylic acids. Polybutylene succinate polymers are known in the art and are described, for example, in European patent application 0 569 153 A2 issued to Showa Highpolymer Company, Limited, of Tokyo, Japan.

A polybutylene succinate-co-adipate polymer is generally prepared by the polymerization of at least one alkyl glycol and more than one aliphatic multifunctional acid. Polybutylene succinate-co-adipate polymers are also known in the art.

Examples of polybutylene succinate polymers and polybutylene succinate-co-adipate polymers that are suitable for use in the present invention include a variety of polybutylene succinate polymers and polybutylene succinate-co-adipate polymers that are available from Showa Highpolymer Company, Limited, of Tokyo, Japan, under the designation polybutylene succinate BIONELLE ™ 1020 or polybutylene succinate-co-adipate polymer BIONELLE ™ 3020, which are essentially linear polymers. These materials are known to be essentially biodegradable.

A polycaprolactone polymer is generally prepared by the polymerization of e-caprolactone. Examples of polycaprolactone polymers that are suitable for use in the present invention include a variety of polycaprolactone polymers that are available from Union Carbide Corporation, of Somerset, New Jersey, under the designation TONE ™ Polymer P767E and TONE ™ Polymer P787 polymers of polycaprolactone. These materials are known to be essentially biodegradable.

It is generally desired that the aliphatic polyester polymer selected from the group consisting of a polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers or a copolymer of such polymers can be present in the thermoplastic composition in an effective amount to result in the thermoplastic composition exhibiting the desired properties. The aliphatic polyester polymer will be present in the thermoplastic composition in a weight amount that is greater than 0 but less than 100 percent by weight, beneficially from about 40 percent by weight to less than about 100 percent by weight, more beneficially from about 50 percent by weight to about 95 percent by weight, suitably from about 60 percent by weight to about 90 percent by weight, more suitably from about 60 percent by weight to about 80 percent by weight , and more suitably between about 70 percent by weight to about 75 percent by weight, wherein all percent by weight is based on the total weight amount of the aliphatic polyester polymer, the multicarboxylic acid, and the wetting agent present in the thermoplastic composition.

It is generally desired that the aliphatic polyester polymer exhibits a weight average molecular weight that is effective for the thermoplastic composition to exhibit a desirable melt strength., a desirable fiber strength and desirable fiber spinning properties. In general, if the weight average molecular weight of an aliphatic polyester polymer is very high, it represents that the polymer chains are heavily entangled which results er. a thermoplastic composition comprising the aliphatic polyester polymer that is difficult to process. Conversely, if the weight average molecular weight of an aliphatic polyester polymer is very low, this means that the polymer chains are not entangled sufficiently which can result in a thermoplastic composition comprising the aliphatic polyester polymer exhibiting a resistance to the relatively weak melt, making high-speed processing very difficult. Thus, the aliphatic polyester polymers suitable for use in the present invention exhibit average weight molecular weights that are beneficially from about 10,000 to about 2,000,000, more beneficially from about 50,000 to about 400,000 and suitably from around 100,000 to around 300,000. The weight average molecular weight for polymers or polymer blends can be determined by methods known to those skilled in the art.

It is also desired that the aliphatic polyester polymer exhibits a polydispersity index value that is effective for the thermoplastic composition to exhibit a melt strength, fiber strength, and desirable fiber spinning properties. As used herein, the "polydispersity index" is meant to represent the value obtained by dividing the weight average molecular weight of a polymer by the average molecular weight of the polymer number. The number average molecular weight for polymers or polymer blends can be determined by methods known to those skilled in the art. In general, if the polydispersity index value of an aliphatic polyester polymer is very high, the thermoplastic composition comprising that aliphatic polyester polymer can be difficult to process due to the inconsistent processing properties caused by the polymer segments comprising low molecular weight polymers that have lower melt strength properties during spinning. Therefore, it is desired that the aliphatic polyester polymer exhibits a polydispersity index value that is beneficially from about: 1 to about 15, more beneficially from about 1 to about 4 and suitably from about 1. to around 3.

It is generally desired that the aliphatic polyether polymer be processable by melting. It is therefore desired that the aliphatic polyester polymer exhibit a melt flow rate that is beneficially from about 1 gram per 10 minutes to about 200 grams per 10 minutes, suitably from about 10 grams per 10 minutes to about from 100 grams per 10 minutes, and more suitably from around 20 grams per 10 minutes to around 40 grams per 10 minutes. The melt flow rate of a material can be determined, for example, according to test method ASTM D1238-E, incorporated herein by reference in its entirety.

In the present invention, it is desired that the aliphatic polyester polymer be essentially biodegradable. As a result of this, the thermoplastic composition comprising the aliphatic polyester polymer, either in the form of a fiber or in the form of a non-woven structure will be essentially degradable when disposed of 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. The biodegradability of a material can be determined using the test method ASTM 5338.92 or the ISO CD 14855 test method, each incorporated herein in its entirety by reference. In a particular embodiment, the biodegradability of a material can be determined using an ASTM 5338.92 test method, wherein the test chambers are maintained at a constant temperature of about 58 degrees centigrade through the test rather than using a profile of increasing temperature.

In the present invention, it is also desired that the aliphatic polyester polymer be essentially compostable.

As a result of this, the thermoplastic composition comprising the aliphatic polyester polymer, either in the form of a fiber or in the form of a non-woven structure will be essentially compostable when disposed of in the environment and exposed to air and / or the water. As used herein, "compostable" is meant to represent that a material is capable of undergoing biological decomposition at a composting site so that the material is not visibly distinguishable and breaks down into carbon dioxide, water, inorganic compounds, and biomaea. , at a rate consistent with known compostable materials.

The second component in the thermoplastic composition is a multicarboxylic acid. A multicarboxylic acid is an acid comprising two or more carboxylic acid groups. In an embodiment of the present invention, it is preferred that the multicarboxylic acid be linear.

Dicarboxylic acids which comprise two carboxylic acid groups are suitable for use in the present invention. It is generally desired that the multicarboxylic acid has a total number of carbons that is not very large because the kinetics of crystallization, the rate at which the crystallization of a fiber or of a prepared nonwoven structure of a thermoplastic composition of the The present invention may be slower than desired. It is therefore desired that the multicarboxylic acid have a total of carbon atoms that is beneficially less than about 30, more beneficially from about 40 to about 30, suitably from about 5 to about 20 and more suitably between about 6 to about 10. Suitable multicarboxylic acids include, but are not limited to, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and mixtures thereof. such acids.

It is generally desired that the multicarboxylic acid be present in the thermoplastic composition in an amount effective to result in the thermoplastic composition exhibiting the desired properties. The multicarboxylic acid will be present in the thermoplastic composition in a weight amount that is greater than about 0 percent by weight, beneficially from more than 0 percent by weight to about 30 percent by weight, more benevolently of about: 1 percent by weight to about 30 percent by weight, suitably from about 5 percent by weight to about 25 percent by weight, more suitably from about 5 percent by weight to about 20 percent by weight, and more appropriately from about 5 percent per weight to about 15 percent by weight, wherein all percent by weight is based on the total weight amount of the aliphatic polyester polymer, the multicarboxylic acid, and the wetting agent present in the composition thermoplastic In order that a thermoplastic composition of the present invention be processed into a product, such as a fiber or a non-woven structure, exhibiting the properties desired in the present invention, it has been found that it is generally known that the multicarboxylic acid beneficially exists in a liquid state during the thermal processing of the thermoplastic composition but that during cooling of the processed thermoplastic composition, the multicarboxylic acid is returned to a solid state, or crystallized, before the aliphatic polyester polymer is returned to a state solid or crystallize.

In the thermoplastic composition of the present invention, the multicarboxylic acid is believed to carry out two important but distinct functions. First, when the thermoplastic composition is in a melted 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 strength of a final product, such as a non-woven structure or a fiber, through the internal modification of the aliphatic polyester polymer. Although no attempt is made to be bound here, it is believed that the multi-carboxylic acid replaces the secondary valence bonds by keeping the aliphatic polyester polymer chains together with the polyester polymer valency bonds multicarboxylic-aliphatic acid, facilitating by both the movement of the polymer chain segments. With this effect, the torsional force required to overturn an extruder is generally reduced dramatically compared to the processing of the aliphatic polyester polymer alone. In addition, the process temperature required to spin the thermoplastic composition to a final product, such as a fiber or a non-woven structure is generally dramatically reduced, thereby decreasing the risk of thermal degradation of the aliphatic polyester polymer while also reducing the amount and cooling rate needed for any fiber or prepared non-woven structure. Second, when a final product prepared from the thermoplastic composition, such as a fiber or a non-woven structure is being cooled and solidifies from its molten liquid state, the multicarboxylic acid is believed to function as a nucleating agent. Aliphatic polyester polymers are known to have a very slow crystallization rate. Traditionally, there are two main ways to resolve this issue. One is the change of the cooling temperature profile in order to maximize the kinetics of crystallization, while the other is to add a nucleating agent to increase the sites and the degree of crystallization.

The cooling process of an extruded polymer at room temperature is usually achieved by blowing air at ambient or sub-ambient temperature onto the extruded polymer. Such a process may be referred to as cooling or super cooling because the change in temperature is usually greater than 100 degrees centigrade and more often greater than 150 degrees centigrade over a relatively short time frame (seconds). By reducing the melt viscosity of a polymer, such a polymer can generally be successfully extruded at lower temperatures. This will generally reduce the temperature change necessary with cooling, preferably to be less than 150 degrees centigrade and, in some cases less than 100 degrees centigrade. To further elaborate this common process on the ideal cooling temperature profile necessary to be the only method of maximizing the crystallization kinetics of aliphatic polyesters in a real manufacturing process is very difficult due to the extreme cooling required within a period of time very short. Normal cooling methods can be used in combination with the second modification method however. The second traditional method is to have a nucleating agent, such as solid particles, mixed with the thermoplastic composition to provide sites to initiate crystallization during cooling. However, such solid nucleating agents generally agglomerate very easily in the thermoplastic composition which can result in blockage of spinner filters and orifices during spinning. In addition, the nucleating effect of such nucleating agents usually peaks at aggregate levels of about 1 percent of such solid nucleating agents. Both of these factors generally reduce the ability or desire to add high percentages of such solid nucleating agents to the thermoplastic composition. In the processing of the thermoplastic composition of the present invention, however, it has been found that the ulticarboxylic acid generally exists in a liquid state during the extrusion process, where the multicarboxylic acid functions as a plasticizer, while the multicarboxylic acid still it is capable of solidifying or crystallizing before the aliphatic polyester during cooling, wherein the multicarboxylic acid functions as a nucleating agent. It is believed that with the cooling of the homogeneous melt, the multi-carboxylic acid solidifies or crystallizes relatively more rapidly and completely just as it falls below its melting point since this is a relatively small molecule. For example, the adipic acid has a melting temperature of about 162 degrees centigrade and a crystallization temperature of about 145 degrees centigrade.

The aliphatic polyester polymer, being a macromolecule, has a relatively very slow crystallization rate which means that when it cools it generally solidifies or crystallizes more slowly and at a lower temperature than its melting temperature. During such cooling, then, the multicarboxylic acid begins to crystallize before the aliphatic polyester polymer and generally acts as solid nucleating sites within the thermoplastic chiller composition.

Another major difficulty encountered in the thermal processing of aliphatic polyester polymers into fibers or non-woven structures is the sticky nature of these polymers. Attempts to pull the fibers, either mechanically, or through an air-pulling process, often result in the addition of fibers to the solid mass. It is generally known that the addition of a solid filler will in most cases act to reduce the tackiness of a polymer melt. Nevertheless, the use of a solid filler can be problematic in a nonwoven or fiber spun application where a polymer is extruded through a hole with a very small diameter. This is because the filler particles tend to clog the orifices of the spinning organ and the filter grids, thereby interrupting the fiber spinning process. In the present invention, in contrast, the poly-carboxylic acid generally remains a liquid during the extrusion process, but then solidifies almost immediately during the cooling process. Thus, the multicarboxylic acid effectively acts as a solid filler, increasing the overall crystallinity of the system and reducing the thickness of the fibers and eliminating problems such as fiber aggregation during pulling.

It is desired that the multicarboxylic acid have a higher level of chemical compatibility with the aliphatic polyester polymer with which the carboxylic acid is being mixed. While the prior art generally demonstrates the possibility of a mixture of adipic acid-polylactide, a unique feature was discovered in this invention. A mixture of adipic acid-polylactide can generally only be mixed with a relatively small amount of a wetting agent, such as less than about 2 percent by weight of a wetting agent and, even only with extreme difficulty. Polybutylene succinate, polybutylene succinate-co-adipate and polycaprolactone have been found to be highly compatible with the large amounts of both a multi-carboxylic acid and a wetting agent. The reason for this is believed to be due to the chemical structure of the aliphatic polyester polymers. Polylactide polymer has a voluminous relative chemical structure, with no linear parts that are larger than CH2. In other words, each segment of CH2 is connected to the carbons carrying either an oxygen or other side chain. Thus, a multicarboxylic acid, such as adipic acid, can not be aligned itself near the polylactide polymer column. In the case of polybutylene succinate, and polybutylene succinate-co-adipate, the polymer column has the repeating units (CH2) 2 and (CH2) 4 within its structure. Polycaprolactone has the repeating unit (CH2) 5. These linear, open, relatively straight portions which are not hindered by the oxygen atoms and the bulky side chains are well aligned with a suitable multicarboxylic acid, such as adipic acid, which also has one unit (CH2). 4 thus allowing a very close contact between the multicarboxylic acid and the suitable aliphatic polyester polymer molecules. This excellent compatibility between the multicarboxylic acid and the aliphatic polyester polymer in these special cases has been found to be relatively easy to allow the incorporation of a wetting agent, the third component in the present invention. Such suitable compatibility is evidenced by the ease of the combination and the production of fiber or non-woven from mixtures containing polybutylene succinate, polybutylene succinate-co-adipate, polycaprolactone, or a mixture or copolymer of these polymers with wetting and acidic agents. suitable multicarboxylic The processability of these mixtures is excellent, whereas in the case of a polycarboxylic acid-polylactide system, a wetting agent can generally not easily be incorporated into the mixture.

Either separately or when mixing mixtures, a polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers or a copolymer of such polymers are generally hydrophobic. Since it is desired that the thermoplastic composition of the present invention and the nonwoven structures or fibers prepared from the thermoplastic composition, generally be hydrophilic, it has been found that there is a need for the use of another component in the thermoplastic composition of the present invention. invention to achieve the desired properties. As such, the thermoplastic composition of the present invention includes a wetting agent.

Thus, the third component of the thermoplastic composition is a wetting agent for the polybutylene succinate polymer, the polybutylene succinate-co-adipate polymer, the polycaprolactone polymer, a mixture of such polymers, and / or a copolymer of such polymers. Suitable surfactants for use in the present invention will generally comprise a hydrophilic section which will generally be compatible with the hydrophilic sections of the polybutylene succinate polymer., a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers and a hydrophobic section which will generally be compatible with the hydrophobic sections of polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers. These hydrophilic and hydrophobic moisturizing agent sections will generally exist in separate blocks so that the overall wetting agent structure can be di-block or random block. A wetting agent with a melting temperature below, or slightly above that of the aliphatic polyester polymer is preferred so that during the cooling process the wetting agent remains liquid after the aliphatic polyester polymer has crystallized. This will generally cause the humidifying agent to migrate to the surface of the prepared fibrous structure, thereby improving the humidifying characteristics and improving the processing of the fibrous structure. It is then generally desired that the wetting agent serve as a surfactant in a processed material of the thermoplastic composition, such as a fiber or non-woven structure, by modifying the contact angle of the water in the air of the processed material. The hydrophobic portion of the wetting agent may be, but is not limited to, a polyolefin such as polyethylene or polypropylene. The hydrophilic moiety of the wetting agent may contain ethylene oxide, ethoxylates, glycols, alcohols or any combinations thereof. Examples of suitable wetting agents include the ethoxylated alcohols UNITHOX® 480 and UNITHOX ™ 750 or the acidic amide ethoxylates UNICID ™ all available from Petrolite Corporation of Tulsa Oklahoma.

Other suitable surfactants may, for example, include one or more of the following: (1) surfactants composed of glycol silicone copolymers such as silicon glycol copolymers D 193 and D 1315 which are available from Dow Corning Corporation, located in Midland, Michigan. (2) ethoxylated alcohols such as ethoxylated alcohols GENAPOL ™ 24-L-60, GENAPOL ™ 24-L-92, or GENAPOL ™ 24-L-98N, which can be obtained from Hoechst Celanese Corporation of Charlotte, North Carolina. (3) surfactants composed of ethoxylated mono- and diglycerides such as MAZOL ™ 80 MGK ethoxylated diglycerides, which are available from PPG Industries, Inc., of Gurnee, Illinois. (4) surfactants composed of carboxylated alcohol ethoxylates, such as the carboxylated alcohol ethoxylates SANDOPAN ™ DTC, SANDOPAN ™ KST, or SANDOPAN ™ DTC-100, which were obtained from Sandoz Chemical Corporation. (5) ethoxylated fatty esters such as the ethoxylated fatty esters TRYLON ™ 5906 and TRYLON ™ 5909, which can be obtained from the Henkel Corporation / Emery Group of Cincinnati, Ohio.

It is generally desired that the wetting agent exhibits a weight average molecular weight that is effective for the thermoplastic composition to exhibit a melt strength, fiber strength and desirable fiber spinning properties. In general, if the weight average molecular weight of a wetting agent is very high, the wetting agent will not mix well with the other components in the thermoplastic composition because the viscosity of the wetting agent will be so high that it lacks the necessary mobility to mix. Conversely, if the weight average molecular weight of the wetting agent is too low, this represents The melting agent will generally not mix bier with the other components and will have such low viscosities that this will cause processing problems, therefore suitable wetting agents for use in the present invention. they exhibit average weight molecular weights that are beneficially from about 1,000 to about 100,000, suitably from about 1,000 to about 5C, 000 and more suitably from about 1,000 to about 10,000.The weight average molecular weight of a wetting agent can be determined using methods known to those skilled in the art.

It is generally desired that the wetting agent exhibit an effective hydrophilic-lipophilic balance ratio (HLB ratio). The hydrophilic-lipophilic balance ratio of a material describes the relative proportion of the hydrophilicity of the material. The hydrophilic-lipophilic balance ratio was calculated as the weight average molecular weight of the hydrophilic part divided by the average molecular weight of the total weight of the material, the value of which was then multiplied by 20. If the value of the hydrophilic balance ratio- Lipophilic is very low, the moisturizing agent will not generally provide the desired improvement in hydrophilicity. Conversely, if the value of the hydrophilic-lipophilic balance ratio is very high, the wetting agent will generally not mix in the thermoplastic composition due to chemical incompatibility and differences in viscosities with other components. Therefore, the humidifying agents useful in the present invention exhibit hydrophilic-lipophilic balance ratio values that are beneficially from about 10 to about 40, suitably from about 10 to about 20, and more suitably from about from 12 to about 16. The hydrophilic-lipophilic balance ratio value for a particular wetting agent is generally well known and / or can be obtained from a variety of known technical references.

It is generally desired that the hydrophobic part of the wetting agent be a linear hydrocarbon chain containing (CH2) n, where n is preferred to be 4 or greater. This hydrophobic linear hydrocarbon part is generally highly compatible with similar sections in polybutylene succinate, in polybutylene succinate-co-adipate, and in polycaprolactone polymers, as well as in many multicarboxylic acids, such as adipic acid. By taking advantage of these structural similarities, the hydrophobic portions of the wetting agent will agglutinate very closely to the aliphatic polyester polymer while: the hydrophilic parts will allow spreading out of: the surface of a prepared fiber or of a non-woven structure. The general consequence of this phenomenon is a relatively large reduction in the advance of the contact angle exhibited by the prepared fiber or a non-woven structure. Examples of suitable wetting agents include the ethoxylated alcohols UNITHOX® 480 and UNITHOX® 750, available from Petrolite Corporation of Tulsa Oklahoma. These wetting agents have an average linear hydrocarbon chain length of between 26 and 50 carbons. If the hydrophobic part of the wetting agent is very bulky, such as with phenyl rings or bulky side chains, such a wetting agent will generally not be well incorporated into the aliphatic polyester polymer blend. Rather than having the hydrophobic parts of the wetting agent being attached to the aliphatic polyester polymer molecules, with the hydrophilic parts of the wetting agent hanging free, the complete molecules of the wetting agent molecules will float freely in the mixture, trapping in the mixture . This is evidenced by a high feed contact angle and a relatively low backward contact angle, indicating that the hydrophilic chains are not on the surface. After a liquid insult, the wetting agent may migrate to the surface resulting in a low backing contact angle. This was clearly demonstrated through the use of the ethoxylated alkyl phenol surfactant IGEPAL ™ RC-630 obtained from Rhone-Poulenc, located in Cranbury, New Jersey. The ethoxylated alkyl phenol INGEPAL ™ RC-630 has a bulky phenyl group which limits its compatibility with aliphatic polyester polymers, as evidenced by the high feed contact angle and the low flashback contact angle of a mixture of a aliphatic polyester polymer and the ethoxylated alkyl phenol IGEPAL ™ RC-630.

It is generally desired that the humidifying agent be present in the thermoplastic composition in an amount effective to result in the thermoplastic composition exhibiting the desired properties such as desirable contact angle values. In general, too much wetting agent can lead to processing problems of the thermoplastic composition or to a final thermoplastic composition which does not exhibit the desired properties such as the desired advancing and receding contact angle values. The moisturizing agent will be beneficially present in the thermoplastic composition in a weight amount that is greater than 0 to about 25 percent by weight, more beneficially of between about 0.5 percent by weight to about 20 percent by weight, suitably from about 1 percent by weight to about 20 percent by weight, and more suitably from about 1 percent by weight to about 15 percent by weight, where all percent by weight is based on the amount of total weight of the polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers; the multicarboxylic acid, and the wetting agent are present in the thermoplastic composition.

Although the main components of the thermoplastic composition of the present invention have been described above, such a thermoplastic composition is not limited thereto and may include other components not adversely affecting the desired properties of the thermoplastic composition. Exemplary materials which may be used as additional components will include, but are not limited to, pigments, antioxidants, stabilizers, surfactants, waxes, flow promoters, solid solvents, plasticizers, nucleating agents, particles. , and other aggregate materials to improve the processing of the thermoplastic composition. If such additional components are included in the thermoplastic composition, it is generally desired that such additional components be in an amount that is beneficially tensile of about 10 percent by weight, more benignly of trenches of about 5 percent by weight, and suitably less than about 1 percent by weight, wherein all percent by weight are based on the total weight amount of the aliphatic polyester polymer selected from the group consisting of of polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers; a multicarboxylic acid; and a wetting agent present in the thermoplastic composition.

The thermoplastic composition of the present invention is generally in simple form a mixture of the aliphatic polyester polymer 5, the multicarboxylic acid, the wetting agent and optionally any additional components. In order to achieve the desired properties for the thermoplastic composition of the present invention, it has been found that it is critical that the polyester polymer The aliphatic, the multicarboxylic acid, and the wetting agent remain essentially unreacted to each other so that a copolymer comprising each of the aliphatic polyester polymer, the multicarboxylic acid and / or the wetting agent is not formed. As such, each of the polymer of The aliphatic polyester, the multicarboxylic acid and the wetting agent remain different components of the thermoplastic composition.

In one embodiment of the present invention, after dry blending together of the aliphatic polyester polymer, the multicarboxylic acid and the wetting agent to form a dry blend of thermoplastic composition, such a dry blend of thermoplastic composition is benevolently stirred, moved otherwise mixed to effectively uniformly mix the aliphatic polyester polymer, the multicarboxylic acid and the wetting agent so that it is formed - • an essentially homogeneous dry mix. The dry mixture can then be mixed with melt in, for example, an extruder to uniformly effectively mix the aliphatic polyester polymer, the multicarboxylic acid, and the wetting agent so that an essentially homogeneous melt is formed. The essentially homogeneous melted mixture can then be cooled and pelletized. Alternatively, the essentially homogeneous melt mixture can be sent directly to a spin pack or other equipment to form the fibers or a non-woven structure.

Alternate methods of mixing together the components of the present invention include adding the multicarboxylic acid and wetting agent to the aliphatic polyester polymer in, for example, an extruder being used to mix the components together. In addition, it is possible to initially mix with melted all the components together at the same time. Other methods of mixing together the components of the present invention are also possible and will be readily recognized by one skilled in the art. In order to determine whether the aliphatic polyester polymer, the multicarboxylic acid and the wetting agent remain essentially unreacted, it is possible to use techniques, such as infrared and nuclear magnetic resonance analysis, to evaluate the chemical characteristics of the thermoplastic composition. final. • tasatitafc- '' '' - Typical conditions for thermally processing the various components include using a cutoff rate that is beneficially between about 100 seconds-1 to about 50,000 seconds "1, more beneficially among about 500 seconds "1 to about 5,000 seconds" 1, suitably from about 1,000 seconds "1 to about 3,000 seconds" 1, and more appropriately about 1,000 seconds "1. Typical conditions for thermally processing the components also include using a temperature that is beneficially between about 50 degrees centigrade to about 500 degrees centigrade, more beneficially between about 75 degrees centigrade to about 300 degrees centigrade and suitably between around 100 degrees centigrade to around 250 degrees centigrade.

As used herein, the term "hydrophobic" refers to a material having a contact angle in water in air of at least 90 degrees. In contrast, as used herein, the term "hydrophilic" refers to a material that has a contact angle of water in air of less than 90 degrees. However, commercial personal care products generally require contact angles that are significantly below 90 degrees in order to provide the desired liquid transport properties. In order to achieve the rapid intake and wetting properties desired for personal care products, the contact angle of ... ^ A * ^ a-Hh-i-aktB-Ki water in air is generally desired to fall below about 70 degrees. In general, the lower the contact angle, the better the wettability. For the purposes of this application, contact angle measurements are determined as set forth in the test methods section given here. The general object of the contact angles and the measurement thereof are well known in the art, for example from the work of Robert J. Good and Robert J. Stromberg, editions in "Surface and Colloid Science - Experimental Methods", volume II (Plenum Press, 1979).

The multicomponent fibers or non-woven structures resulting from the present invention are desired to exhibit an improvement in hydrophilicity, evidenced by a decrease in the contact angle of water in air. The contact angle of water in air of a fiber sample can be measured as either an advancing contact angle value or a receding value due to the nature of the test procedure. The advancing contact angle measures an initial response of the material to a liquid, such as water. The back contact angle gives a measure of how a material will behave over the duration of a first discharge, or exposure to the liquid, as well as over the following discharges. A lower recoil contact angle means that the material becomes more hydrophilic during exposure to the liquid and that it will generally then be able to transport liquids more consistently. Both forward and reverse contact angle data are desirably used to establish the highly hydrophilic nature of a multi-component fiber or non-woven structure of the present invention.

The non-woven structures or multicomponent fibers resulting from the present invention are desired to exhibit an improvement in the liquid transport rate, as evidenced by a low contact angle hysteresis. As used herein, contact angle hysteresis is defined as the difference between forward and reverse contact angles for a material that is being evaluated. For example, a relatively high forward contact angle and a relatively low backward contact angle will lead to a large contact angle hysteresis. In such a case, an initial liquid discharge will generally be slowly absorbed by a material, even though the material will generally retain the liquid once it is absorbed. In general, the relatively low forward and backward contact angles, as well as the small contact angle hysteresis, are desired in order to have a high rate of liquid transport. The contact angle hysteresis can be used as an indication of the transmission rate of a liquid on the material being evaluated.

In an embodiment of the present invention, it is desired that a non-woven structure or multicomponent fiber prepared from the thermoplastic composition disclosed herein exhibit an advancing contact angle value that is beneficially less than about 70 degrees, more beneficially from mencs. about 65 degrees, suitably less than about 60 5 degrees, more adequately less than about 55 degrees, and more adequately less than about 50 degrees, wherein the advance contact angle value was determined by the method that is described in the test methods section given here.

In another embodiment of the present invention, it is desired that a multicomponent fiber or a non-woven structure prepared from the thermoplastic composition described herein exhibit a retrograde contact angle value that beneficially is less than about 60 degrees, more benevolently from mencs of about 55 degrees, suitably less than about 50 degrees, more adequately less than about 45 degrees, and more adequately less than about 40 degrees, wherein the contact angle value of the backing is determined by the method that is described in the given test methods section here.

In another embodiment of the invention, it is desired that a multicomponent fiber or a non-woven structure prepared from the thermoplastic composition disclosed herein exhibit a Advance contact angle value that beneficially be at least about 10 degrees, more beneficially at least about 15 degrees, suitably at least about 20 degrees, and more adequately at least mentions about 25 degrees, less than the advance contact angle value that is exhibited by a non-woven structure or otherwise essentially identical fiber prepared from a thermoplastic composition that does not comprise a wetting agent.

In another embodiment of the present invention, it is desired that a multicomponent fiber or a non-woven structure prepared from the thermoplastic composition described herein exhibit a contact angle value that recedes that beneficially at least 5 degrees, more beneficially at least about 10 degrees, suitably less than about 15 degrees, and more adequately at least about 20 degrees, less than the value of the receding contact angle that is exhibited by a fiber or otherwise essentially identical non-woven structure prepared from a thermoplastic composition that does not comprise a wetting agent.

As used herein, the term "an otherwise essentially idyllic nonwoven fiber or structure prepared from a thermoplastic composition that does not comprise a wetting agent" and other similar terms, is intended to refer to a control fiber or non-conductive structure. woven, which is prepared using essentially identical materials and an essentially identical process as compared to a fiber or a non-woven structure of the present invention, except that the control fiber or the non-woven structure of control. it does not comprise or is not prepared with the wetting agent described herein.

In another embodiment of the present invention, it is desired that the difference between the advancing contact angle value and the recoil contact angle value referred to as the contact angle hysteresis be as small as possible. As such, it is desired that the multimode fiber exhibits a difference between the advancing contact angle value and the recoil contact angle value that is beneficially less than about 50 degrees, more beneficially less than about 40 degrees. degrees, suitably less than about 30 degrees and more adequately less than about 20 degrees.

It is generally desired that the melt softening temperature of the thermoplastic composition be within a range that is typically found in most process applications. As such, it is generally desired: that the temperature of melting or softening of the thermoplastic composition beneficially be from less than about 25 degrees centigrade to about 350 degrees centigrade, more beneficially than it is between about 35 degrees centigrade to about 300 degrees Celsius, and suitably it is between about 45 degrees Celsius to around 250 degrees Celsius.

The thermoplastic composition of the present invention has been found to exhibit generally improved processing properties compared to a thermoplastic composition comprising the aliphatic polyester polymer but none of the multicarboxylic acid and / or the wetting agent. This is generally due to the significant reduction in viscosity that occurs due to the multicarboxylic acid and the internal lubricating effect of the wetting agent. Without the multicarboxylic acid, the viscosity of: a mixture of the aliphatic polyester polymer and the wetting agent is generally too high to process. If the wetting agent, a mixture of aliphatic polyester polymer and multicarboxylic acid is generally not a sufficiently hydrophilic material and generally does not have the processing advantages of the liquid wetting agent in the cooling zone. It has been discovered as part of the present invention that only with the correct combination of the three components can the proper melt strength for fiber spinning be achieved.

As used herein, the improved processing of a thermoplastic composition is measured as a decline in the apparent viscosity of the thermoplastic composition at a temperature of about 170 degrees centigrade and at a cut-off rate of about 1,000 seconds "1, conditions! Typical industrial extrusion processing If the thermoplastic composition exhibits an apparent viscosity that is very high, the thermoplastic composition will generally be difficult to process In contrast, if the thermoplastic composition exhibits an apparent viscosity that is very low, the thermoplastic composition will result in a extruded fiber that has a very poor tensile strength.

Therefore, it is generally desired that the thermoplastic composition exhibit an apparent viscosity value at a temperature of about 170 degrees centigrade and a cutoff rate of about 1,000 seconds "1 which is beneficially between about 5 seconds pascals (Pa. s) to about 200 second pascals, more beneficially from about 10 pascals seconds to about 150 pascals seconds, and suitably from about 20 pascals seconds to about 100 pascals seconds.The method by which the viscosity value apparent was determined is established below in relation to the examples.

As used herein, the term "fiber" or "fibrous" is meant to refer to a material wherein the length-to-diameter ratio of such material is greater than about 10.

Conversely, a "non-fiber" or "non-fibrous" material is wanted M ^ referring to a material where the length-to-diameter ratio of such material is around 10 or less.

The methods for making the fibers are well known and do not require to be described here in detail. The melt spinning of the polymers includes the production of continuous filament structures such as unidaei fibers with meltblown and non-continuous filament yarns such as short staple fibers. To form a meltblown or meltblown fiber, a thermoplastic composition is generally extruded and supplied to a distribution system wherein the thermoplastic composition is introduced into: a spinning organ plate. The spun fiber is then cooled, solidified, pulled by an aerodynamic system and then formed into a conventional nonwoven. Meanwhile, to produce a short or artificial cut the spun fiber is cooled, solidified and pulled, usually by a system of mechanical rolls, to a harvested fiber and intermediate filament diameter rather than being formed directly into a structure non-woven Subsequently, the collected fiber can be "cold drawn" at a temperature below its softening temperature, to the desired finished fiber diameter and can be followed by curling / texturing and cutting to a desirable fiber length. The fibers can be cut into relatively short lengths such as short fibers which generally have lengths in the range of about 25 to about 50 millimeters and short staple fibers which are even shorter and generally have lengths of less than about of 18 millimeters.

The thermoplastic composition of the present invention is suitable for preparing nonwoven fibers or structures that can be used in disposable products including disposable absorbent products such as diapers, incontinent adult products, and bed pads; in catamenial devices such as sanitary toadlas and plugs; and other absorbent products such as cleansing wipes, bibs, wound dressings and surgical covers or coats. Therefore, in another aspect, the present invention relates to a disposable absorbent product comprising the multicomponent fibers of the present invention.

In an embodiment of the present invention, the thermoplastic composition is formed in a fibrous matrix for incorporation into a disposable absorbent product. A fibrous matrix may take the form of, for example, a fibrous non-woven fabric. Fibrous non-woven fabrics can be made 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 are to be degraded in water, for example, in a toilet, it is advantageous for the lengths to be maintained at or below about 15 millimeters.

In one embodiment of the present invention, there is provided a disposable absorbent product, which disposable absorbent product comprises a liquid permeable topsheet, a lower sheet attached to the liquid permeable topsheet, and an absorbent structure placed between the topsheet permeable to the liquid. liquid and the lower sheet, wherein the lower sheet comprises fibers prepared from the thermoplastic composition of the present invention.

Exemplary disposable absorbent products are generally described in U.S. Patent Nos. US-A-4,710,187; US-A-4,762,521; US-A-4,770,656; and US-A-4,798,603; whose references are incorporated here by this mention.

Absorbent products and structures according to all aspects of the present invention are generally subjected, during use, to multiple discharges of a body fluid. Thus, absorbent products and structures are desirably capable of absorbing multiple discharges of body fluids in amounts to which absorbent products and structures will be exposed during use. The downloads are usually A .. «te * M-fc - ^, ... . .. - __- -.:, ^. ^^ fa., -. separated from each other for a period of time.

Test Methods Melting Temperature The melting temperature of a material L was determined using differential scanning calorimetry. Differential scanning calorimetry, available from T. A. Instruments, Inc. of New Castle, Delaware, under the designation Differential Exploration Calorimetry Thermal Analyst 2910 (DSC), which was equipped with a liquid nitrogen cooling accessory and was used in combination with the Thermal Analyst 2200 analysis software program, was used for the determination of melting temperatures.

The samples of material tested were either in the form of fibers or pellets of resin. It is preferred not to handle the samples of material directly, but rather to use tweezers and other tools so as not to introduce anything that could produce erroneous results. The material samples were cut, in the case of the fibers, or placed in the case of the resin pellets, in an aluminum tray and weighed to an accuracy of 0.01 milligrams on an analytical balance. If necessary, a lid was folded inward over the sample of material on the tray.

The differential scanning calorimetry was calibrated using an indium metal standard and a baseline correction was carried out, as described in the manual for the differential scanning calorimeter. A sample of material was placed in the differential scanning calorimeter test chamber for the test and an empty tray was used as a reference. The entire test was run with 55 cubic centimeters / nitrogen purge (industrial class) minute on the test chamber. The heating and cooling program is a 2-cycle test that begins with the camera's equilibrium at minus 20 degrees Celsius, followed by the heating cycle of 20 degrees Celsius / minute at 220 degrees Celsius, followed by the heating cycle. cooling to 20 degrees Celsius / minute at minus 20 degrees Celsius, and then to another heating cycle of 20 degrees Celsius / minute at 220 degrees Celsius.

The results were evaluated using the computer program of analysis in which the endothermic and exothermic peaks were identified and quantified.

Apparent viscosity A capillary rheometer, under the designation. capillary rheometer Rheomat Rheograph 2003, which was used in combination with an inRHEO analysis computer program gj? ^^ (version 2.31) both available from the Gottfried Company of Rock Hill, South Carolina, was used to evaluate the rheological properties of apparent viscosity of the material samples. The placement of the capillary rheometer included a pressure transducer of 2,000 bars (200 MPa) and a round hole capillary vessel 30 millimeters long / 30 millimeters active length / 1 millimeter diameter / 0 millimeters height / 180 degrees run in angle.

If the sample of material being tested shows or is known to be sensitive to water, the sample of material is dried in a vacuum oven above its glass transition temperature, for example above 55 or 60 degrees Celsius for the poly (lactic acid) materials, under a vacuum of at least 15 inches of mercury (381 mm Hg) with a nitrogen gas purge of at least 30 standard cubic feet per hour (about 0.850 cubic meters per hour) ) for at least 16 hours.

Once the instrument is warmed and the pressure transducer is calibrated, the material sample L is increasingly loaded into the column, packing the polymer resin pellets in the column with one rod at a time to ensure consistent melting during the test. . After loading the sample material, a melting time of 4 minutes precedes each test to allow the material sample to melt completely at the test temperature. The capillary rheometer automatically takes data points and determines the apparent viscosity (in pascals-seconds) at 7 apparent cutoff rates (in seconds "1): 50, 100, 200, 1000, 2000, and 5000. When the curve is examined It is important that the curve be relatively smooth.If there are significant deviations from a general curve, from one point to another, possibly due to the air in the column, the running test must be repeated to confirm the results.

The rheology curve resulting from the apparent shear rate versus apparent viscosity gives an indication of how the material sample will run at that temperature in an extrusion process. The values! of apparent viscosity at a temperature of about 170 degrees centigrade and at a cut rate of about 1000 seconds "1 are of specific interest because these are typical conditions found in commercial fiber spinning extruders.

Contact Angle The equipment consists of an inDCA computer program (version 1.02) and a DCA-322 dynamic contact angle analyzer, both available from ATI-CAHN Instruments, Inc. of Madison, Wisconsin. The test was done on an "A" circuit with a bound balance agitation. The calibrations must be made on the balance of the contact angle analyzer with a mass of 100 mg before starting the measurements as indicated in the manual. The motor must also be calibrated periodically as indicated in the manual.

The thermoplastic compositions are spun into fibers and the free fall sample (0 jet) was used for the determination of the contact angle. Care should be taken through fiber preparation to minimize fiber exposure to handling to ensure that contamination is kept to a minimum. The fiber sample is attached to a wire hook with a scotch tape so that 2-3 centimeters of fiber extends beyond the end of the hook. The hook consists of a 4-centimeter piece of straight wire that is bent about 0.8 inches from the end so that it forms a hook on that end. Then the fiber sample was cut with a razor so that 1.5 centimeters extend beyond the end of the garcho. An optical microscope, such as the Leica Galen III, manufactured by Leica, Inc. of Buffalo, New York, was used to determine the average diameter (from 3 to 4 measurements) along the fiber.

The sample on the wire hook was suspended from the agitation balance on a circuit "A" of the contact angle analyzer. The immersion liquid is ^^^^^^ distilled water and changed for each specimen. The specimen parameters are entered (for example fiber diameter) and the test is started. The phase advances to 151.75 microns / second until it detects the Zero Depth of immersion when the fiber makes contact with the surface of the distilled water. From the Zero Depth of immersion, the fiber advances inside the water by 1 centimeter, stays for approximately 0 seconds and then immediately backs off 1 centimeter. The auto-analysis of the contact angle made by the computer program determines the forward and backward contact angles of the fiber sample based on the normal calculations identified in the manual. Contact angles of 0 or less than 0 indicate that the sample has become fully wettable. Five duplicates are tested for each sample and the statistical analysis was calculated for the mean standard deviation and the percentage coefficient of variation. As reported in the examples given here and as used in the claims, the advance contact angle value represents the advancing contact angle of the distilled water on a fiber sample determined according to the preceding test method. Similarly, as reported in the examples given here and as used in the claims, the backward contact angle value represents the backward contact angle of the distilled water on a fiber sample determined according to the method of previous test. The contact angle hysteresis was defined as the difference between the forward and backward contact angles. All values reported here represent the principal values determined based on the five duplicate measurements.

Non Woven Tension Test The tensile properties of the non-woven fabrics were measured on a Sintech l / D model, obtained from MTS Systems Corporation, a company located in Eden Prairie Minnesota, using the Testworks 3.03 analysis computer program also obtained from MTS Systems Corporation . A set of pneumatic tension lugs from ION were obtained from MTS (model MTS number 00.01659) and covered with rubber grip covers (model MTS number 38.00401). A 50-pound load cell (about 200N) was used for this test method, and rubber-coated air-operated handles are attached to the machine. The energy for both the load cell and the load frame was turned on and the equipment was given a minimum of half an hour for heating and stabilization. After this time has elapsed, the test handles are moved manually until there is a gap of 7.62 centimeters between the upper and lower handles, as measured with a rubber and a level. The distance is then set: to 0 over the test computer program. The handles are open and the load cell is calibrated.

-Mu-- The samples were cut into strips of 2.54 centimeters in width which were placed vertically on the handles so that there is no tension on the sample. The test was started by the program and the initial grip is raised at a rate of 12.0 inches per minute (30.48 centimeters per minute), while the lower handle remains stationary. The test continues until the nonwoven fails and the upper handle returns to its starting point. The computer program then displays the measured and calculated properties of the sample. The information of specific interest is the peak and breaking load, whose quantities are measured directly by the machine. The peak load is the maximum load at any point during the test and is measured in grams. The load to the break is the load, in grams, when the sample fails.

Cup Crush Test The cup crush test was carried out on a Sintech l / D model obtained from MTS Systems Corporation, a company located in Eden Prairie Minnesota, using the Testworks 3.03 analysis computer program also obtained from MTS Systems Corporation. In this method a load cell of 10 pounds (about 50N) was attached to the Sintech frame. A forming cylinder is placed on the bottom support and a non-woven square of 15.24 centimeters by 15.24 centimeters was placed over the mouth of the cylinder. Cup ^ t M ^^? ¿m a ^ iJÍM-Mit.-.

The former was placed on the nonwoven forming the nonwoven on the cylinder, leaving an open circle of the exposed fabric on top of the cylinder. The foot of the cup crush device consists of a metal rod with a rounded end and is attached to the 10-pound load cell. When the test was started, the foot descends at a rate of 409.40 millimeters per minute into the non-woven fabric, crushing it. The Sintech then measures the peak load and the energy required to crush the nonwoven. The foot descends to a total distance of 62 millimeters and then it stops, reverses the direction and returns to its original position. In general, a lower peak load indicates a softer nonwoven.

EXAMPLES Various materials were used as components to form thermoplastic compositions and multicomponent fibers in the following examples. The designation and various properties of these materials are listed in Table 1.

Poly (lactic acid) polymer (PLA) was obtained from Chronopol Inc., of Golden, Colorado, under the designation HEPLON ™ A10005 poly (lactic acid) polymer. In Table 2, the poly (lactic acid) HEPLON ™ A10005 polymer is designated as HEPLON.

Polybutylene succinate polymer, available from Showa Highpolymer Company, Limited, Tokyo, Japan, under the designation polybutylene succinate BIONELLE ™ 1020 was obtained. In Table 2, the polybutylene succinate polymer BIONELLE ™ 1020 is designated PBS.

A polybutylene succinate-co-adipate, available from Showa Highpolymer Company, Limited, of Tokyo, Japan, was obtained under the designation of BUTTEELLE ™ 3020 polybutylene succinate-co-adipate. In Table 2, the succinate-co-polymer - BIONELLE ™ 3020 Polybutylene Adipate is designated as PBSA.

A polycaprolactone polymer was obtained from Union Carbide Chemicals and Plastics Company, Inc., under the designation Polycarbonate TONE ™ Polymer P767E. In Table 2, the polycaprolactone polymer TONE ™ Polymer E767E is designated PCL.

A material used as a wetting agent was obtained from Petrolite Corporation of Tulsa, Oklahoma, under the designation ethoxylated alcohol UNITHOX ™ 480, which exhibited an average number-average molecular weight of about 2250 percent of ethoxylate of about 80 percent by weight , a melting temperature of around 65 degrees centigrade and a lipophilic hydrophilic balance value of around 16.

In Table 2, the ethoxylated alcohol UNITHOX ™ 480 is designated as Wetting Agent A.

A material used as a wetting agent "was obtained from Baker Petrolite Corporation of Tulsa, Oklahoma, under the designation acidic amide ethoxylate UNICID ™ X-8198, which demonstrated a lipophilic hydrophilic balance value of approximately 35 and a melting temperature. of about 60 degrees centigrade In Table 2, the acid amide ethoxylate UNICID ™ X-8198 was designated as Wetting Aggregate B.

A material used as a wetting agent was obtained from Rhone-Poulenc, located in Cranbury, New Jersey, under the designation surfactant of ethoxylated alkyl phenol IGEPAL ™ RC-630, which demonstrated a lipophilic hydrophilic balance value of about 12.7 and a melting temperature of around 4 degrees centigrade. In Table 2, the ethoxylated alkyl phenol surfactant IGEPAL ™ RC-630 is designated as Wetting Agent C.

Sample Preparation To prepare a specific thermoplastic composition, the various components were first mixed dry and then mixed with melt in a twin counter-rotating screw extruder to provide vigorous mixing of the components. The specific materials used in the following examples, and the relative amounts used of each material are shown in Table 2. Melting mixing involves the partial or complete melting of the components combined with the cutting effect of the rotating mixing screws. Such conditions are conducive to optimum mixing and even dispersion of the components of the thermoplastic composition. Twin screw extruders such as the twin screw extruder Haake Rheocord 90 available from Haake GmbH of Karlsautte, Germany, or a mixer -a * faith »Sa¿- J m *. - &- Brabender twin screw (category number 05-96-000) available from Brabender Instruments of South Hackensack, New Jersey, or other comparable twin screw extruders are well suited for this task. This also includes co-rottope twin screw extruders such as the ZSK-30 extruder, available from Werner and Pfleiderer Corporation of Ramsey, New Jersey. Unless otherwise indicated, all samples were prepared on a twin screw extruder Haake Rheocord 90. The melted composition is cooled after extrusion from the melt mixer onto either a liquid cooled surface or roller and / or or by forced air passed over the extrudate. The cooled composition is then subsequently pelletized for conversion to fibers.

The conversion of these resins into fibers and non-wovens was carried out on a spinning line at home with an extruder with a diameter of 1, 905 centimeters. The extruder was a screw with a ratio of 24: 1 L: D (length: diameter) and three heating zones which were fed into: a transfer pipe from the extruder to the spin pack. The transfer pipe constitutes the fourth and fifth heating zones and contains a 0.62 inch diameter KOCH ™ SMX static mixing unit, available from Koch Engineering Company, Inc. of New York, New York. The transfer pipe extends inside the head of hi.lado . .. ^ 2¡ &., .1 & L ». (sixth heating zone) and through the spin plate with numerous small holes through which the melted polymer is extruded. The temperatures of these heating zones for each composition produced are given in Table 2. The spinning plate used here had 15 holes, where each hole had a diameter of 0.508 millimeters. The fibers are cooled by air using air at a temperature of 13 degrees Celsius to 22 degrees Celsius, pulled down by a mechanical pull roller, and passed over either a winding unit for harvesting or a fiber pulling unit for bonding with spinning and urion. Alternatively, other accessory equipment may be used for pre-harvest treatment. The non-pulled free-fall fibers were then evaluated with respect to the contact angle and the pelletized resin for the melt rheology. The results of this characterization are given in the Table.

Examples 1-7 In these examples, the polymers of succinatc-polybutene adipate BIONELLE 3020 and polybutylene succinate BIONELLE 1020 were mixed with melt in equal amounts by weight to provide vigorous mixing of the two components on a co-rotating twin screw extruder ZSK -30 manufactured by Werner and Pfleiderer. The resulting threads were air-cooled and pelleted. The resulting pellets were mixed with air with adipic acid (product number AD 130 from Spectrum Quality Products, Inc.) and the ethoxylated alcohol moistener UNITHOX 480 and then mixed with melted and spun into fibers according to the aforementioned procedure. Three of these examples (samples 1, 3 and 4) were put through a Lurgi process and joined with calendering to form a non-woven fabric. Cup and strain crush tests were carried out on these tissues and the results are shown in Table 4.

Example 8 In this example, polymers of polybutylene succinate BIONELLE 1020 and polybutylene succinate-co-adipate BIONELLE 3020 were mixed with melt in equal amounts by weight to provide vigorous mixing of the two components on a co-rotating twin screw extruder ZSK -30 manufactured by Werner and Pfleiderer. The resulting yarns were cooled with air and then pelleted. The resulting pellets were dry mixed with malonic acid (from Aldrich Chemical Company, Inc., of Milwaukee, Wisconsin, catalog number M129-6) and the ethoxylated alcohol wetting agent UNITHOX 480 and then mixed with melted and spinning of fiber were tried according to the aforementioned method. Attempts to produce fibers were unsuccessful due to severe matrix swelling U t m ia and the dripping of the polymer.

Example 9 In this example, polymers of BUTTELLE 1020 polybutylene succinate and BIONELLE 3020 polybutylene succinate-co-adipate were blended with melt in equal weight amounts to provide vigorous mixing of the two components on a torus extruder. co-rotating twin ZSK-30 manufactured by Werner and Pfleiderer. The resulting yarns were air cooled and pelletized. The resulting pellets were dry-blended with glutaric acid (from Aldrich Chemical Company, Inc., of Milwaukee, Wisconsin, catalog number G340-7) and the wetting agent of ethoxylated alcohol UNITHOX 480 and then mixed with melted and spun into fibers according to the above-mentioned process.

Example 10 20 In this example, the polybutylene succinate polymers BIONELLE 1020 and polybutylene succinate-co-adipate BIONELLE 3020 were mixed with melt in equal amounts by weight to provide vigorous mixing of the two components on a screw extruder. co-rotating twin ZSK-30 manufactured by Werner and Pfleiderer.

-M-ilílii-MMlH- ^? J The resulting threads were cooled by air and then pelletized. The resulting pellets were dry blended with suberic acid (Aldrich Chemical Company, Inc., of Milwaukee, Wisconsin, catalog number S520-0) and the ethoxylated alcohol wetting agent UNITHOX 480 and then mixed with melted and spun into fibers. according to the procedure mentioned above.

Example 11 In this example, the polybutylene succinate polymers BIONELLE 1020 and polybutylene succinate-co-adipate BIONELLE 3020 were mixed with melted in equal amounts by weight to provide vigorous mixing of the two components on a co-rotating twin thyme extruder. ZSK-30 manufactured by Werner and Pfleiderer. The resulting yarns were cooled by air and then pelletized. The resulting pellets were dry blended with adipic acid (from Spectrum Quality Products, Inc. AD130) and ethoxylated alkyl phenol IGEPAL RC-630 wetting agent and mixed with melted and spun into fibers as described above.

Example 12 • "., • In this example, polymers of BUTTELLE 1020 polybutylene succinate and BIONELLE 3020 polybutylene succinate-co-adipate were blended with melted in equal weight amounts to provide vigorous mixing of the two components on an extruder. twin co-rotating screw ZSK-30 manufactured by Werner and Pfleiderer.

The resulting yarns were cooled by air and then pelletized. The pellets were dry blended with adipic acid (Spectrum Quality Products, Inc. product number AD130) and acidic acid ethoxylate humidifier UNICID X-8198 and mixed with melted and spun into fibers following the previously described method.

Examples 13-20 In these examples, the polycaprolactone polymer TONE Polymer P767E mixed with melted adipic acid (Spectrum Quality Products, Inc. product number AD130) and the ethoxylated alcohol moistening agent UNITHOX 480 and the fiber samples were prepared according to the techniques described above.

Example 21 In this example, TONE Polymer P767E polycaprolactone polymer was mixed with melted with citric acid (Aldrich Chemical Company, Milwaukee, Wisconsin, product number 24062-1) and UNITHOX 480 ethoxylated alcohol wetting agent and fiber spinning was attempted according to the technique described above. The five samples were not produced due to the foaming and bubbling of the melted resin.

Examples 22-26 In these examples, the poly (lactic acid) HEPLON A10005 polymer was melted and mixed with adipic acid (Spectrum Quality Products, Inc. product number AD130) and the ethoxylated alcohol moistening agent UNITHOX 480 and the fiber samples were prepared according to the aforementioned technique. The combination of samples 23 and 25 was difficult due to the emergence of the extruded yarns and the division of the wetting agent due to the incompatibility of the polylactide, the adipic acid, and the ethoxylated alcohol moistening agent UNITHOX 480.

Those skilled in the art will recognize that the present invention is capable of many modifications and deviations without departing from the scope thereof. Therefore, the detailed description and examples set forth above are intended 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.

TABLE It is not an example of the present invention T A B L A 2 (cont.) Wetting Agent (grams) * Not an example of the present invention T A B L A It is not an example of the present invention T A B L A 10 Stress Properties Cup Crushing Properties fifteen .

Claims

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

1. A thermoplastic composition comprising a mixture of: to. an aliphatic polyester polymer selected from the group consisting of polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers, wherein the polymer Aliphatic polyester exhibits a weight average molecular weight that is from about 10,000 to about: 2,000,000 where the aliphatic polyester polymer is present in the thermoplastic composition in a weight amount that is between about 40 to less than about 100 percent by weight; b. 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 from greater than about 0 percent by weight to about of 30 percent by weight; Y c. a wetting agent, which exhibits a hydrophilic-lipophilic balance ratio that is between about 10 to about 40, in a weight amount that is greater than 0 to about 25 percent by weight, wherein all percent by weight are based on the total weight amount of the aliphatic polyester polymer, the multicarboxylic acid, and the wetting agent present in the thermoplastic composition; wherein the thermoplastic composition exhibits an apparent viscosity value at a temperature of about 170 degrees centigrade and at a cutoff rate of about 1000 seconds "1 which is between about 5 Pascal seconds and about 200 Pascal seconds.

2. The thermoplastic composition as claimed in clause 1 characterized in that the aliphatic polyester polymer is a polymer of polybutylene succinate.

3. The thermoplastic composition as claimed in clause 1 characterized in that the aliphatic polyester polymer is a polybutylene succinate-co-adipate polymer.

4. The thermoplastic composition as claimed in clause 1 characterized in that the aliphatic polyester polymer is a polycaprolactone polymer.

5. The thermoplastic composition as claimed in clause 1 characterized in that the aliphatic polyester polymer is present in the thermoplastic composition in a weight amount that is between about 50 percent by weight to about 95 percent by weight.

6. The thermoplastic composition such and such is claimed in clause 5 characterized in that the aliphatic polyester polymer is present in the thermoplastic composition in an amount of weight that is between about 60 weight percent to about 90 weight percent.

7. The thermoplastic composition tal and cotro is claimed in clause 1 characterized in that the multicarboxylic acid is selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and a mixture of such acids.

8. The thermoplastic composition as claimed in clause 7 characterized in that the multicarboxylic acid is selected from the group consisting of glutaric acid, adipic acid, and suberic acid.

9. The thermoplastic composition as claimed in clause 1 characterized in that the acid - ^ "^ * - 'Multicarboxylic is present in the thermoplastic composition in a weight amount that is between about 1 percent by weight to about 30 percent by weight.

10. The thermoplastic composition as claimed in clause 9 characterized in that the multicarboxylic acid is present in the thermoplastic composition in an amount of weight that is between about 5 percent by weight to about 25 percent by weight.

11. The thermoplastic composition as claimed in clause 1 characterized in that the multicarboxylic acid has a total of carbon atoms that is between about 4 to about 30. 15 1.

The thermoplastic composition as claimed in clause 1 characterized in that the wetting agent exhibits a hydrophilic-lipophilic balance ratio which is between about 10 to about 20.

13. The thermoplastic composition tal and cotro is claimed in clause 1 characterized in that the wetting agent is present in the thermoplastic composition in a weight amount that is between about 0.5 percent by weight. 25 weight at around 20 percent by weight. -. ^ m -. ^ - - * - ^ - * ". *" -. ** .. J-I .-- A ^ &.

14. The thermoplastic composition as claimed in clause 1 characterized in that the wetting agent is present in the thermoplastic composition in an amount of weight that is between about 1 percent by weight to about 15 percent by weight.

15. The thermoplastic composition as claimed in clause 1 characterized in that the wetting agent is selected from the group consisting of ethoxylated alcohols, acid amide ethoxylates and ethoxylated alkyl feroles.

16. The thermoplastic composition as claimed in clause 1 characterized in that the aliphatic polyester polymer is present in the thermoplastic composition in an amount by weight that is between about 50 percent by weight to about 95 percent by weight, the acid The multicarboxylic acid is selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and a mixture of such acids and is present in the thermoplastic composition in a weight amount that is between about 1 weight percent to about 30 weight percent, and the wetting agent is selected from the group consisting of ethoxylated alcohols, acid amide ethoxylates and ethoxylated alkyl phenols and is present in the thermoplastic composition in an amount by weight that it is between about 0.5 percent by weight to about 20 percent by weight.

17. A fiber prepared from a thermoplastic composition, the thermoplastic composition comprises a mixture of: to. an aliphatic polyester polymer selected from the group consisting of polybutylene succinat.o polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers, wherein the aliphatic polyester polymer exhibits a weight average molecular weight that is between about 10,000 to about 2,000,000, wherein the aliphatic polyester polymer is present in the thermoplastic composition in a weight amount that is around 40 to less than 100 percent by weight; b. 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 a weight amount that is between more than 0 percent by weight to about 30 percent by weight; Y a wetting agent, which exhibits a hydrophilic-lipophilic balance ratio that is from about 10 to about 40, in a weight amount that is greater than 0 to about 25 percent by weight, where t. All the percentages by weight are based on the total weight amount of the aliphatic polyester polymer, the multicarboxylic acid, and the wetting agent present in the thermoplastic composition; wherein the fiber exhibits an advance contact angle value that is less than about 70 degrees and a recoil contact angle value that is less than about 60 degrees.

18. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is present in the thermoplastic composition in an amount by weight that is between about 50 percent by weight to about 95 percent by weight.

19. The fiber as claimed in clause 18 characterized in that the aliphatic polyester polymer is present in the thermoplastic composition in an amount by weight that is between about 60 percent by weight to about 90 percent by weight.

20. The fiber as claimed in clause 17 characterized in that the multicarboxylic acid is selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and a mixture of such acids .

21. The fiber as claimed in clause 20 characterized in that the multicarboxylic acid is selected from the group consisting of glutaric acid, adipic acid, and suberic acid.

22. The fiber as claimed in clause 17 characterized in that the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 1 percent by weight to about 30 percent by weight.

23. The fiber as claimed in clause 22 characterized in that the multicarboxylic acid is present in the thermoplastic composition in an amount by weight that is between about 5 percent by weight to about 25 percent by weight.

24. The fiber as claimed in clause 17 characterized in that the multicarboxylic acid has a total of carbon atoms that is between about 4 to about 30. - "* *" * - 25.

The fiber as claimed in clause 17 characterized in that the wetting agent exhibits a hydrophilic-lipophilic balance ratio that is about 10 to about 20.

The fiber as claimed in clause 17 characterized in that the wetting agent is present in the thermoplastic composition in an amount of weight that is between about 0.5 percent by weight to about 0 of 20 percent by weight.

27. The fiber as claimed in clause 26 characterized in that the wetting agent is present in the thermoplastic composition in an amount by weight that is between about 1 percent by weight to about 15 percent by weight.

28. The fiber as claimed in clause 17 characterized in that the wetting agent is selected from the group consisting of ethoxylated ethoxylates, acid amide ethoxylates and ethoxylated alkyl phenols.

29. The fiber as claimed in clause 17 characterized in that the fiber exhibits a value of advancing contact angle that is less than about 65 degrees.

30. The fiber as claimed in clause 17 characterized in that the fiber exhibits a receding contact angle value that is less than about 55 degrees.

31. The fiber as claimed in clause 17 characterized in that the fiber exhibits a receding contact angle value that is less than about 50 degrees.

32. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is present in the thermoplastic composition in an amount by weight that is between about 50 percent by weight. 15 weight to about 95 percent by weight, the multicarboxylic acid is selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and a mixture of such acids and is present in the thermoplastic composition in a Amount per weight which is between about 1 percent by weight to about 30 percent by weight, and the wetting agent is selected from the group consisting of ethoxylated alcohols, ethoxylated acid ethoxylates and ethoxylated alkyl phenols and is present in the composition thermoplastic in 25 an amount by weight that is between about 0.5 percent by weight to about 20 percent by weight. ^ j -3Mtt * - «-

33. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is polybutylene succinate polymer, the multicarboxylic acid is adipic acid, the wetting agent is an ethoxylated alcohol .

34. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is polybutylene succinate-co-adipate polymer, the multicarboxylic acid is adipic acid, and the wetting agent is an ethoxylated alcohol.

35. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is a mixture of polybutylene succinate polymer and polybutylene succinate-co-adipate polymer, the multicarboxylic acid is adipic acid, and the wetting agent e: s an ethoxylated alcohol.

36. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is a mixture of polybutylene succinate polymer and polybutylene succinate-co-adipate polymer, the multicarboxylic acid is glutaric acid, and the wetting agent is an ethoxylated alcohol.

37. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is a mixture of polybutylene succinate polymer and polybutylene succinate-co-adipate polymer, the multicarboxylic acid is suberic acid, and the wetting agent is an ethoxylated alcohol.

38. The fiber as claimed in clause 17 characterized in that the aliphatic polyester polymer is polycaprolactone polymer, the multicarboxylic acid is adipic acid, and the wetting agent is an ethoxylated alcohol. ifr "¿ru *" * - R E S U M E N A thermoplastic composition comprising an unreacted mixture of an aliphatic polyester polymer selected from the group consisting of polybutylene succinate polymer, a polybutylene succinate-co-adipate polymer, a polycaprolactone polymer, a mixture of such polymers, or a copolymer of such polymers; a multicarboxylic acid; and a wetting agent. 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 intended for the absorption of fluids such as body fluids. W »•« • &ni * $ tíummfcafi * B.