JP2003514136A - Biodegradable non-woven polylactide nonwoven having fluid treatment properties and disposable absorbent products containing the same - Google Patents

Abstract

  (57) [Summary] The present invention relates to biodegradable nonwoven materials and disposable absorbent products with improved fluid handling properties. The nonwoven material can be made using a thermoplastic composition comprising a poly (lactic acid) polymer; a polybutylene succinate polymer, a polybutylene succinate adipate polymer, or a mixture of such polymers; and a wetting agent. Thermoplastic compositions exhibit substantially biodegradable properties but are easy to process. Biodegradable nonwoven materials can be used in disposable absorbent products intended for absorbing liquids such as body secretions.

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates to biodegradable non-woven materials with improved liquid handling properties and disposable absorbent products containing the same. Nonwoven materials can be made from polymer blends. Such formulations can include multi-component fibers. Such multi-component fibers are
Includes unreacted mixtures of polybutylene succinate polymers, polybutylene succinate adipate polymers, or mixtures of such polymers. Multi-component fibers are substantially biodegradable but easy to process. The biodegradable non-woven material is
It can be used as a disposable product for absorbing liquids such as body secretions.

BACKGROUND ART Currently, disposable absorbent products are widely used in many applications. For example, in the infant and pediatric care field, diapers and training pants have generally been replaced by reusable cloth absorbent articles. Other typical disposable absorbent products include feminine care products such as sanitary napkins or tampons, adult incontinence products, and healthcare products such as sterile surgical cloth or wound dressings. A typical disposable absorbent product generally consists of a composite structure that includes a topsheet, a backsheet, and an absorbent structure between the topsheet and the backsheet. These products typically include some type of fastening system to secure the product to the wearer.

[0003] Typically, disposable absorbent products are made up of one such substance as water, urine, menses, or blood when used.
Subject to one or more liquid emissions. Thus, the backsheet material of the outer cover of a disposable absorbent product typically maintains the integrity of the disposable absorbent product during use by the wearer and prevents leakage of liquid released into the product. It is made of liquid insoluble and liquid impermeable material such as polypropylene film that shows sufficient strength and throughput.

While current disposable baby diapers and other disposable absorbent products are generally accepted on the market, these products are still in need of improvement in certain areas. For example, many disposable absorbent products can be difficult to dispose of. For example, attempts to flush many disposable absorbent products into flush toilets into the sewer system typically cause clogging of the toilet or the pipe connecting the toilet and the sewer system. In particular, the outer cover materials typically used in disposable absorbent articles generally do not decompose or disperse when flushed down the toilet, so disposable absorbent products cannot be disposed of in this manner. If the outer cover material is made so thin as to reduce the overall bulk of the disposable absorbent product so that the likelihood of clogging the toilet or sewer pipes is reduced, the outer cover material will not be worn by the wearer. It may not exhibit sufficient strength to prevent it from breaking or tearing under the stress of normal use.

Moreover, solid waste disposal is of increasing interest worldwide. As waste landfills continue to fill, reducing the material resources of disposable products, incorporating more recyclable and / or degradable ingredients into disposable products, and solid waste disposal facilities such as landfill sites. There is an increasing demand for the design of products that can be disposed of by methods other than disposal.

Therefore, there is a need for new materials that generally maintain integrity and strength during use, but that can be used in disposable absorbent products that can be efficiently disposed of after use. For example, disposable absorbent products can be easily and efficiently disposed of by composting. Alternatively, the disposable absorbent product can be easily and efficiently disposed of in a liquid sewer system and the disposable absorbent product can be degraded. Also, although degradable single component fibers are known, there are problems with their use. In particular, known degradable fibers generally do not have good thermal dimensional stability, and usually the fibers are harsh due to relaxation of polymer chains during downstream heat treatment steps such as thermal bonding or lamination. Undergoes significant heat shrinkage.

For example, fibers prepared from poly (lactic acid) polymers are known, but there are problems with their use. In particular, poly (lactic acid) polymers are known to have a relatively slow crystallization rate as compared with, for example, polyolefin polymers, and therefore aliphatic polyester polymers are often inferior in processability. Moreover, poly (lactic acid) polymers generally do not have good thermal dimensional stability. Generally, without extra treatment such as heat curing, poly (lactic acid) polymers undergo severe heat shrinkage due to polymer chain relaxation during downstream heat treatment steps such as thermal bonding or lamination. However, in general, such thermoset treatments limit the use of fibers in in-situ nonwoven forming processes such as spunbonding and meltblowing, where it is very difficult to obtain thermoset.

Moreover, one important component of many personal care articles is the bodyside liner. The liner typically consists of a surfactant-treated polyolefin spunbond. For incorporation of spunbond into a liner, it is desirable for the material to be wettable and facilitate liquid uptake. In addition to rapid uptake, composite absorbent products are desirable to keep the user's skin dry. Further, the spunbond material desirably has a soft feel to the skin. Current spunbond diaper liners have many problems associated with them. First, it is composed of a polyolefin material and does not decompose. Due to the hydrophobic nature of these materials, it is necessary to treat the liner with a surfactant to make it wettable. Since the surfactant does not permanently stick to the polyolefin, it tends to flow out during repeated releases, increasing the uptake time of the nonwoven. Therefore, there is a need for nonwoven materials useful as wettable structures that have improved fluid handling properties such as short uptake times and improved skin dryness. Further, there is a need for nonwoven materials that are biodegradable while achieving these improved fluid handling properties.

DISCLOSURE OF THE INVENTION Accordingly, it is desirable to provide nonwoven materials and disposable absorbent articles having improved fluid handling properties. It is also desirable to provide non-woven materials and disposable absorbent articles that have a short uptake time. It is also desirable to provide nonwoven materials and disposable absorbent articles that have improved skin dryness. It is also desirable to provide nonwoven materials and disposable absorbent articles that are biodegradable while having improved fluid handling properties. It would also be desirable to provide nonwoven materials and disposable absorbent articles that include thermoplastic compositions that exhibit the desired processability, liquid wettability, and thermodimensional stability properties. It is also desirable to provide non-woven materials and disposable absorbent articles that include a thermoplastic composition that can be easily and efficiently formed into fibers. It would also be desirable to provide nonwoven materials and disposable absorbent articles that include a thermoplastic composition suitable for use in preparing nonwoven structures. It would also be desirable to provide a disposable absorbent product that can be used to absorb fluids such as bodily secretions, but which contains components that are readily degraded in the environment.

These requirements are in accordance with the present invention to provide a nonwoven material comprising a thermoplastic composition that is substantially biodegradable but is easy to prepare and easy to process into the desired final nonwoven structure. Will be realized. One aspect of the present invention relates to a nonwoven material having a thermoplastic composition that includes a mixture of a first component, a second component, and a third component. One embodiment of such a thermoplastic composition is a poly (lactic acid) polymer; a polybutylene succinate polymer, a polybutylene succinate adipate polymer, or a mixture of such polymers; and a poly (lactic acid) polymer, a poly (lactic acid) polymer. It includes an unreacted mixture of wetting agents for butylene succinate polymers, polybutylene succinate adipate polymers, or mixtures of such polymers.

In another aspect, the invention relates to a multi-component fiber that is substantially degradable, yet easy to prepare and easy to process into the desired final nonwoven structure. One aspect of the invention is poly (lactic acid) polymers; polybutylene succinate polymers, polybutylene succinate adipate polymers, or mixtures of such polymers; and aliphatic polyester polymers, and polybutylene succinate polymers, poly Includes unreacted admixture of wetting agents for butylene succinate adipate polymers, or mixtures of such polymers.

[0012] In another aspect, the invention relates to a nonwoven structure having the multicomponent fibers disclosed herein. One embodiment of such a non-woven structure is a frontsheet useful in disposable absorbent products. In another aspect, the invention relates to a process for preparing the nonwoven materials disclosed herein. In another aspect, the present invention relates to disposable absorbent products that include the multi-component fibers disclosed herein.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a biodegradable nonwoven material and a disposable absorbent material comprising a thermoplastic composition having a first component, a second component, and a third component. Regarding sex articles. As used herein, the term "thermoplastic" refers to a material that softens when exposed to heat and returns substantially to its original state when cooled to room temperature. It is possible to prepare a thermoplastic composition by using a poly (lactic acid) polymer; a polybutylene succinate polymer, a polybutylene succinate adipate polymer, or a mixture of such polymers; an unreacted mixture of wetting agents. You can
It has been found that such thermoplastic compositions, while substantially degradable, can be readily processed into fibers or nonwoven structures that exhibit effective fiber mechanical properties.

The first component of the thermoplastic composition is a poly (lactic acid) polymer. Generally, poly (lactic acid) polymers are prepared by polymerizing lactic acid. However, if you are
It will also be appreciated that chemically equivalent materials can be prepared by polymerization of lactide. Thus, as used herein, the term "poly (lactic acid) polymer" is intended to refer to polymers prepared by the polymerization of either lactic acid or lactide.

Lactic acid and lactide are known as asymmetric molecules and have two optical isomers, called levorotatory (hereinafter L) and dextrorotatory (hereinafter R) optical isomers, respectively. There is. As a result, it is possible to prepare different polymers that are chemically similar but have different properties by polymerizing a particular optical isomer or by using a mixture of two optical isomers. . For more information, see poly (
It has been found that modifying the stereochemistry of a (lactic acid) polymer can control, for example, the melt temperature, melt rheology, and crystallinity of the polymer. By making it possible to control such properties, it is possible to prepare a thermoplastic composition and a multi-component fiber having desired melt strength, mechanical properties, flexibility and processability, and to obtain a fine thermosetting crimped fiber. Can be made. Examples of poly (lactic acid) polymers suitable for the present invention include Chronopol Inc., located in Golden, Colorado. There may be mentioned various poly (lactic acid) polymers available from

Generally, it is desirable that the poly (lactic acid) polymer be present in the thermoplastic composition in an amount effective to produce a thermoplastic composition that exhibits the desired properties. The poly (lactic acid) polymer is greater than 0% and less than 100% by weight, preferably about 5% by weight.
To about 95 weight percent, suitably between about 10 weight percent and about 90 weight percent, and more suitably between about 15 weight percent and about 85 weight percent, in the thermoplastic composition. However, all weight percentages are based on the total weight of the poly (lactic acid) polymer; polybutylene succinate polymer, polybutylene succinate adipate polymer, or a mixture of such polymers; and wetting agent. Generally, the compositional ratio of the three components of the thermoplastic composition is important to obtain the desired properties of the thermoplastic composition such as wettability, biodegradability, thermal stability, and processability.

The second component of the thermoplastic composition is a polybutylene succinate polymer, a polybutylene succinate adipate polymer, or a mixture of such polymers. Generally, polybutylene succinate polymers are prepared by the condensation polymerization of glycols with dicarboxylic acids or their anhydrides. The polybutylene succinate polymer may be either a linear structure polymer or a long chain branched structure polymer. In general, long chain branched structure polybutylene succinate polymers are prepared using an additional polyfunctional component selected from the group consisting of trifunctional or tetrafunctional polyhydric alcohols, oxycal carboxylic acids, and polybasic carboxylic acids. Is prepared. Polybutylene succinate polymers are known in the art, for example, Showa Highpolymer Co. of Tokyo, Japan. , Ltd. European Patent Application Publication No. 0569153. Generally, polybutylene succinate adipate polymers are prepared by the polymerization of at least one alkyl glycol and two or more aliphatic polyfunctional acids. Polybutylene succinate adipate polymers are known in the art.

Examples of polybutylene succinate polymers and polybutylene succinate adipate polymers suitable for use in the present invention are Show, located in Tokyo, Japan.
a Highpolymer Co. , Ltd., long-chain branched structure, Bion
ole 1903 polybutylene succinate polymer or a variety of polybutylene succinate adipate polymers available under the name of Bionolle 1020 polybutylene succinate adipate polymer having a substantially linear structure. You can

Generally, the polybutylene succinate polymer, polybutylene succinate adipate polymer, or mixture of such polymers is present in the thermoplastic composition in an amount effective to produce a thermoplastic composition exhibiting the desired properties. It is desirable to exist. The polybutylene succinate polymer, polybutylene succinate adipate polymer, or mixture of such polymers is suitable at greater than 0 weight percent and less than 100 weight percent, advantageously between about 5 weight percent and about 95 weight percent. Can be present in the thermoplastic composition between about 10% and about 90% by weight, and more suitably between about 15% and about 85% by weight, but all weight percentages can be present in the thermoplastic composition. Lactic acid) polymers; polybutylene succinate polymers, polybutylene succinate adipate polymers, or mixtures of such polymers; and wetting agents.

In general, the poly (lactic acid) polymer, polybutylene succinate polymer and / or polybutylene succinate adipate polymer are effective for thermoplastic compositions to exhibit desirable melt strength, fiber mechanical strength, and fiber spinning properties. It is desirable to exhibit a different weight average molecular weight. In general, if the weight average molecular weight of a particular polymer is too high, the polymer chains are highly entangled, making processing of thermoplastic compositions containing that polymer difficult. In contrast, if the weight average molecular weight of a particular polymer is too low, the polymer chains are not sufficiently entangled and the thermoplastic composition containing the polymer exhibits relatively weak melt strength and is processed at high speeds. Becomes very difficult. Accordingly, a poly (lactic acid) polymer, polybutylene succinate polymer and / or polybutylene succinate adipate polymer suitable for use in the present invention is advantageously between about 10,000 and about 2,000,000. More preferably it exhibits a weight average molecular weight of between about 50,000 and about 400,000, suitably between about 100,000 and about 300,000. Weight average molecular weights for polymers and polymer mixtures can be measured using the methods described in the Test Methods section herein.

The poly (lactic acid) polymer, polybutylene succinate polymer, and / or polybutylene succinate adipate polymer are also effective in exhibiting desirable melt strength, fiber mechanical strength, and fiber spinning properties of the thermoplastic composition. It is desirable to show different polydispersity index values. As used herein, "polydispersity index" is meant to represent the value obtained by dividing the weight average molecular weight of a polymer by the number average molecular weight of that polymer. In general, if the polydispersity index value of a particular polymer is too large, the thermoplastic composition containing that polymer will undergo conflicting processing during spinning caused by polymer segments containing low molecular weight polymers having low melt strength properties. Due to the characteristics, processing becomes difficult. Thus, the poly (lactic acid) polymer, polybutylene succinate polymer and / or polybutylene succinate adipate polymer is preferably between about 1 and about 15, more preferably between about 1 and about 4, Suitably it is desirable to exhibit a polydispersity index value between about 1 and about 3. The number average molecular weight of a polymer or polymer blend can be measured using the methods described in the Test Methods section of this specification.

In the present invention, the poly (lactic acid) polymer, polybutylene succinate polymer, or polybutylene succinate adipate polymer is preferably biodegradable. Thus, a non-woven material comprising a thermoplastic composition can be substantially degraded when disposed of in the environment and exposed to air and / or water. As used herein, "biodegradable" means that the material degrades by the action of naturally occurring microorganisms such as bacteria, fungi, and algae.

In the present invention, the poly (lactic acid) polymer, the polybutylene succinate polymer, or the polybutylene succinate adipate polymer is preferably compostable. As such, nonwoven materials containing aliphatic polyester polymers are substantially compostable when disposed of in the environment and exposed to air and / or water. As used herein, "compostable" means that the material undergoes biodegradation at the composting site to the same extent that the material is visually indistinguishable from known compostable materials. It means that it can be decomposed into carbon dioxide, water, inorganic compounds, and biomass.

As used herein, the term “hydrophobic” refers to a material that has a water contact angle in air of at least 90 degrees. In contrast, as used herein, the term "affinity" refers to materials that have a water contact angle in air of less than 90 degrees. In the present application, the measured value of the water contact angle is measured by the method shown in the column of the test method of the present specification. The general contents of the contact angle and its measuring method are, for example,
Robert J. Good and Robert J. et al. "Surface and Colloid Science-Exper" edited by Stromberg
mental Method "Vol. II, (Plenum Press,
1979) and are known in the art.

The poly (lactic acid) polymer, polybutylene succinate polymer, polybutylene succinate adipate polymer, or mixtures of such polymers are desirably melt processable. Therefore, the polymer used in the present invention is advantageously about 1
Exhibiting a melt flow rate of from gram / 10 minutes to about 600 grams / 10 minutes, suitably from about 5 grams / 10 minutes to about 200 grams / 10 minutes, more suitably from about 10 grams / 10 minutes to about 150 grams / 10 minutes. Is desirable. The melt flow rate of a material can be measured according to ASTM test method D1238-E, the entire disclosure of which is incorporated herein by reference.

As used herein, “fiber” or “fibrous” refers to a material having a length to diameter ratio of greater than about 10. In contrast, "non-fiber" or "non-fibrous" means
A material having a length to diameter ratio of about 10 or less.

The poly (lactic acid) polymer and the polybutylene succinate polymer and / or the polybutylene succinate adipate polymer are hydrophobic, either alone or when mixed. Since it is generally desirable that the biodegradable nonwoven fabric prepared with the thermoplastic composition of the present invention be hydrophilic, it is necessary to use other components in the thermoplastic composition of the present invention to obtain the desired properties. I know that. Further, such polymers are somewhat chemically incompatible and therefore adversely affect the processability of polymer blends, and therefore poly (lactic acid) polymers, and polybutylene succinate polymers and / or polybutylene succinates. It has also been found desirable to improve the processability of adipate polymers. For example, poly (lactic acid) polymers, and polybutylene succinate polymers and / or polybutylene succinate adipate polymers can be difficult to effectively mix and prepare by themselves as a substantially homogeneous mixture. Thus, the present invention generally provides a single thermoplastic, wetting agent that enables effective preparation and processing of poly (lactic acid) polymers, and polybutylene succinate polymers and / or polybutylene succinate adipate polymers. It requires use in a composition.

Accordingly, the third component of the thermoplastic composition is a wetting agent for the poly (lactic acid) polymer and the polybutylene succinate polymer and / or polybutylene succinate adipate polymer. In general, wetting agents suitable for use in the present invention generally include poly (lactic acid) polymers, and hydrophilic moieties compatible with the hydrophilic moieties of polybutylene succinate polymers or polybutylene succinate adipate polymers, and generally poly (lactic acid) polymers. It may include a hydrophobic portion of a butylene succinate polymer or a polybutylene succinate adipate polymer and a compatible hydrophobic portion. Generally, these hydrophilic and hydrophobic portions of the wetting agent are present in discrete blocks such that the overall wetting agent structure can be diblock or random blocks. In general, it is desirable that the wetting agent function as a substance that enhances the bond strength between the plasticizer and the different polymers to improve the preparation and processability of the thermoplastic composition initially. The wetting agent then desirably functions as a surfactant in the nonwoven material made from the thermoplastic composition by modifying the water contact angle of the material being processed in air. The hydrophobic portion of the wetting agent may be a polyolefin such as, but not limited to, polyethylene or polypropylene. The hydrophilic portion of the wetting agent can include ethylene oxide, ethoxylates, glycols, alcohols, or any combination thereof. Examples of suitable wetting agents are UNITH
Mention may be made of OX®480 and UNITHOX®750 ethoxylated alcohols, or UNICID® acid amide ethoxylates, all Petrolite Corp. located in Tulsa, OK.
It is available from ation.

Generally, it is desirable that the wetting agent exhibit a weight average molecular weight effective to exhibit the desired melt strength, fiber mechanical strength, and fiber spinning properties of the thermoplastic composition. In general,
If the weight average molecular weight of the wetting agent is too high, the wetting agent does not mix well with the other components in the thermoplastic composition because the wetting agent has a high viscosity and lacks the fluidity required for formulation. In contrast, if the weight average molecular weight of the wetting agent is too low, the wetting agent generally does not mix well with the other ingredients, resulting in low viscosity and processing problems. Accordingly, wetting agents suitable for use in the present invention are advantageously between about 1,000 and about 100,000, suitably between about 1,000 and about 50,000, more suitably about 1,000
To a weight average molecular weight of between about 10,000 and about 10,000. The weight average molecular weight of poly (lactic acid) can be measured using the method described in the test method section of this specification.

In general, wetting agents should exhibit an effective hydrophilic-hydrophobic balance ratio (HLB ratio). The HLB ratio of a material represents the relative hydrophilicity of the material. The HLB ratio is calculated as the weight average molecular weight of the hydrophilic portion divided by the total weight average molecular weight of the material and multiplied by 20. If the HLB ratio value is too low, the wetting agent generally cannot provide the desired hydrophilicity improvement. Conversely, if the HLB ratio value is too high, the wetting agent cannot be incorporated into the thermoplastic composition due to chemical incompatibility and viscosity differences with other ingredients. Accordingly, wetting agents useful in the present invention are advantageously between about 10 and about 40, suitably between about 10 and about 20, and more suitably about 12.
The values of the HLB ratio which are between 1 and about 16 are shown.

Generally, it is desirable that the wetting agent be present in the thermoplastic composition in an amount effective to produce a thermoplastic composition that exhibits the desired properties, such as desired contact angle values. In general, the minimum amount of wetting agent will be required to achieve effective formulation and processing with the other ingredients in the thermoplastic composition. In general, too much compatibilizer causes processing problems in the thermoplastic composition or results in a final thermoplastic composition that does not exhibit the desired properties such as desired advancing and receding contact angle values. The humectant is greater than 0 up to about 15 weight percent, preferably between about 0.5 weight percent and about 15 weight percent, and more preferably between about 1 weight percent and about 13 weight percent.
Suitably between about 1 weight percent and about 10 weight percent, more suitably between about 1 weight percent and about 5 weight percent are present in the thermoplastic composition, but all weight percents are Poly (lactic acid) polymer present in the plastic composition; polybutylene succinate polymer, polybutylene succinate,
Adipate polymer, or a mixture of such polymers; and the total weight of wetting agents.

Although the major components of the thermoplastic composition used in the present invention have been described above, such a thermoplastic composition is not limited to adversely affecting the desired properties of the thermoplastic composition. May be included. Exemplary materials that can be used as additional components include, but are not limited to, pigments, antioxidants, stabilizers, surfactants, waxes, flow promoters, solid solvents, plasticizers, nucleating agents, There are particles and other materials added to enhance the processability of the thermoplastic composition. When such additional components are included in the thermoplastic composition, such additional components are preferably less than about 10 weight percent, more preferably less than about 5 weight percent, suitably about 1 weight percent. It is desirable to use less than percent and all weight percentages are
It is based on the total weight of poly (lactic acid) polymer; polybutylene succinate polymer, polybutylene succinate adipate polymer, or a mixture of such polymers, and wetting agent present in the thermoplastic composition.

Generally, the final form of the thermoplastic composition used in the present invention is a poly (lactic acid) polymer; a polybutylene succinate polymer, a polybutylene succinate adipate polymer, or a mixture of such polymers; and wetting. Agent, and optionally a mixture of optional additional ingredients. To obtain the desired properties for the thermoplastic compositions of the present invention, the poly (lactic acid) polymer; polybutylene succinate polymer, polybutylene succinate adipate polymer, or mixtures of such polymers; and wetting agents are: It is desirable that they remain substantially unreacted with each other. Thus, each of the poly (lactic acid) polymer; the polybutylene succinate polymer, the polybutylene succinate adipate polymer, or a mixture of such polymers; and the wetting agent remains a separate component of the thermoplastic composition.

Generally, each of the poly (lactic acid) polymer and the polybutylene succinate polymer, the polybutylene succinate adipate polymer, or a mixture of such polymers is separately in a prepared mixture forming a thermoplastic composition. Form a region or domain of. However, depending on the relative amounts of each of the poly (lactic acid) polymer and polybutylene succinate polymer, polybutylene succinate adipate polymer, or mixture of such polymers used, a substantially continuous phase may be thermoplastic composition. It can also be formed from a polymer that is present in a relatively large amount in the object. In contrast, too little polymer present in the thermoplastic composition forms a substantially discontinuous phase, where distinct regions or domains form within the continuous phase of the predominant polymer, where the predominant The continuous phase of such a polymer substantially entraps the recessive polymer within its structure. As used herein, "encapsulate" and related terms mean that the continuous phase of the predominant polymer surrounds or surrounds discrete regions or domains of the substantially recessive polymer.

In one embodiment of the thermoplastic composition or multi-component fiber used in the present invention,
The poly (lactic acid) polymer forms a substantially continuous phase and the polybutylene succinate polymer, polybutylene succinate adipate polymer, or mixture of such polymers forms a substantially discontinuous phase. Preferably poly (
The lactic acid) polymer substantially entraps regions or domains of polybutylene succinate polymer, polybutylene succinate adipate polymer, or a mixture of such polymers. In such embodiments, the poly (lactic acid) polymer is present in the thermoplastic composition or in the multi-component fiber at between about 75 weight percent and about 90 weight percent and comprises a polybutylene succinate polymer, a polybutylene succinate polymer. Nate-adipate polymers, or mixtures of such polymers,
Desirably present between about 5 weight percent and about 25 weight percent in the thermoplastic composition or in the multi-component fiber, all weight percents are present in the thermoplastic composition or in the multi-component fiber, Poly (lactic acid) polymer; polybutylene succinate polymer, polybutylene succinate adipate polymer, or mixtures of such polymers; and wetting agent total weight.

In one embodiment of the present invention, a poly (lactic acid) polymer; a polybutylene succinate polymer, a polybutylene succinate adipate polymer, or a mixture of such polymers; and a wetting agent are dry mixed and thermoplastic. After forming the dry mixture of the composition, the dry mixture is effectively agitated, agitated, or otherwise compounded to provide a poly (lactic acid) polymer; polybutylene succinate polymer, polybutylene succinate. The adipate polymer, or mixture of such polymers; and the wetting agent are effectively and uniformly mixed to form a substantially uniform dry mixture. The dry mixture is then melt compounded, for example in an extruder, to effectively add a poly (lactic acid) polymer; a polybutylene succinate polymer, a polybutylene succinate adipate polymer, or a mixture of such polymers; and a wetting agent. Mix uniformly to form a substantially uniform melt mixture. The substantially homogeneous melt mixture is then cooled and pelletized. Alternatively, the substantially homogeneous melt mixture can be sent directly to a spin pack or other device to form a nonwoven material.

Another method of mixing the components of the present invention together is, for example, in the extruder used to mix the components, first with the poly (lactic acid) polymer and then with the polybutylene succinate polymer, polybutylene succinate. Mention may be made of the nate-adipate polymer, or a mixture of such polymers, mixed together and then the wetting agent added. Furthermore, it is also possible to first melt mix all components simultaneously. Other methods of mixing the components of the present invention together are possible and will be readily apparent to those skilled in the art.

The present invention also uses multicomponent fibers, which are prepared from the thermoplastic compositions of the present invention. The present invention is illustratively described with respect to a multi-component fiber having only three components. However, it is to be understood that the scope of the present invention is intended to include fibers having three or more components. When forming the thermoplastic composition into multicomponent fibers, the exposed surface of at least a portion of the multicomponent fibers will typically be formed from the predominant polymer present in the multicomponent fibers. The exposed surface of at least a portion of the multicomponent fiber will generally allow the multicomponent fiber to be thermally bonded to other fibers that are the same or different than the multicomponent fiber of the present invention. As a result, the multicomponent fibers can be used to form thermally bonded non-woven fiber structures such as non-woven webs.

[0039]   Typical conditions for thermal processing of the various components are advantageously about 100 seconds.^-1 From about 50,000 seconds^-1Until about 500 seconds more advantageous^-1From about 5000 seconds ^-1 Until about 1000 seconds^-1From about 3000 seconds^-1Until the most appropriate
Is about 1000 seconds^-1The utilization of a shear rate that is Also heat the ingredients
Typical conditions for processing are advantageously about 100 ° C to about 500 ° C.
And more advantageously between about 125 ° C and about 300 seconds ° C,
Mention may be made of the use of temperatures between about 150 ° C and about 250 ° C.

Methods of making multi-component fibers are known and need not be discussed at length here.
Polymer melt-spinning methods can include the production of continuous filaments such as spunbond or meltblown, and discontinuous filaments such as staple and shortcut fibers. Generally, to form spunbond or meltblown fibers, the thermoplastic composition is extruded and sent to a distribution system where the thermoplastic composition is introduced into a spinneret plate. The spun fibers are then cooled, solidified, drawn by an aerodynamic system, and then formed into a conventional non-woven fabric. Meanwhile, to produce shortcuts or staples, the spun fibers are not directly formed into a non-woven structure, but are cooled, solidified and generally drawn by a mechanical roll system into a collection fiber of intermediate filament size. It The collected fibers may then be "cold drawn" to a desired final fiber diameter at a temperature below their softening temperature and then crimped or textured to cut them to the desired fiber length.

The step of cooling the extruded thermoplastic composition to ambient temperature is usually accomplished by blowing ambient or sub-ambient temperature air onto the extruded thermoplastic composition. Since the temperature change is usually 100 ° C. or higher and often 150 ° C. or higher in a relatively short time such as several seconds, it can be called rapid cooling or supercooling. Multicomponent fibers may be cut into relatively short lengths, such as staple fibers, which generally have a length in the range of about 25 to about 50 millimeters, and even shorter shortcut fibers, which generally have a length of less than about 18 millimeters. it can. See, for example, US Pat. No. 4,789,592 to Taniguchi et al. And US Pat. No. 5,366,552 to Strack et al., The entire disclosures of which are incorporated herein by reference. Please refer.

It is desired that the resulting multicomponent fibers exhibit improved hydrophilicity as evidenced by a reduction in water contact angle in air. The water contact angle of a fiber sample in air can be measured as the advancing or receding contact angle value because of the nature of the test procedure. The advancing contact angle indicates the initial response of the material to a liquid such as water. The receding contact angle provides a measure of how the material behaves over the first release or exposure to liquid and over the next release. The smaller the receding contact angle, the more hydrophilic the material will be during exposure to the liquid, which generally means that the liquid can be moved more reliably. Both advancing and receding contact angle data are preferably used to establish the high degree of hydrophilicity of the multi-component fiber or nonwoven structure of the present invention.

Thus, in one embodiment of the present invention, the multicomponent fiber is advantageously less than about 80 degrees, more advantageously less than about 75 degrees, suitably less than about 70 degrees, and more suitably about 60 degrees.
Advancing contact angle values are measured by the methods described in the Test Methods section herein, although it is desirable to exhibit advancing contact angle values that are less than 50 degrees, and most suitably less than about 50 degrees. In another embodiment of the invention, the multi-component fiber is advantageously less than about 60 degrees, more advantageously less than about 55 degrees, suitably less than about 50 degrees, even more suitably less than about 45 degrees, most suitably. Although it is desirable to exhibit a receding contact angle value that is less than about 40 degrees, the receding contact angle value is measured by the method described in the Test Methods section herein.

In another embodiment of the present invention, the difference between the advancing contact angle value and the receding contact angle value, known as contact angle hysteresis, is desirably as small as possible. Thus, the multicomponent fiber has a difference between the advancing contact angle value and the receding contact angle value that is preferably less than about 30 degrees, more preferably less than about 25 degrees, suitably less than about 20 degrees, and more suitably. It is desirable to exhibit less than about 10 degrees.

Typical poly (lactic acid) polymer materials often undergo thermal shrinkage during downstream heat treatments. Thermal shrinkage occurs primarily due to chain relaxation of the polymer segments in the thermally induced amorphous and imperfect crystalline phases. To solve this problem, one generally maximizes crystallization of the poly (lactic acid) polymer prior to the coupling step so that the thermal energy does not cause chain relaxation or incomplete crystal structure realignment, It is desirable to be able to direct the melt directly. A typical solution to this problem is to heat cure the material. Thus, when the prepared material, such as fibers, is sent to a bond roll for thermosetting, the fibers will not shrink substantially as they are already fully or highly oriented. The present invention solves the need for this additional step by virtue of the multi-component fiber morphology. In general, the addition of polybutylene succinate polymer, polybutylene succinate adipate polymer, or a mixture of such polymers, and wetting agents will reduce the heat of multicomponent fibers compared to fibers prepared with poly (lactic acid) polymers alone. Shrinkage is reduced.

In one embodiment of the invention, the non-woven material has a temperature of about 90 ° C.
It is desirable to utilize a thermoplastic composition or multicomponent fiber that exhibits a heat shrinkage of preferably less than about 15 percent, more preferably less than about 10 percent, suitably less than about 5 percent, and the shrinkage is determined by the fiber. Based on the difference between the initial and final length of the fiber divided by the initial fiber length and multiplied by 100. The methods by which the amount of shrinkage exhibited by the fibers can be measured are given in the Test Methods section of this specification.

In one embodiment of the invention, the multi-component fiber desirably exhibits a heat shrinkage of less than about 5 percent at a temperature of about 90 ° C., thereby forming the multi-component fiber. The non-woven structure has a quilting or non-woven action that increases the surface area of the non-woven structure because the non-woven structure exhibits a three-dimensional shape due to the shrinkage of the multi-component fibers. The quilting or non-woven action of the non-woven structure has been found to improve flexibility and liquid Z-axis movement within the non-woven structure.

It is also generally desirable for the multicomponent fibers to exhibit desired mechanical strength properties such as fracture stress values as well as tensile stress values so that the nonwoven material maintains its integrity during use. In one embodiment of the invention, the multicomponent fiber prepared with the thermoplastic composition described above comprises
It is desirable to exhibit improved fracture stress values as well as improved tensile stress values as compared to fibers prepared with poly (lactic acid) polymer alone. Also, in one embodiment of the invention, the multi-component fiber has at least 2 of the fracture stress values exhibited by the same fiber except that a single poly (lactic acid) polymer is used to prepare the multi-component fiber. It is desirable to show a double breaking stress value.

In one embodiment of the present invention, the multicomponent fiber desirably exhibits a fracture stress value of about 10 MPa or higher, advantageously 15 MPa or higher, suitably 20 MPa or higher and up to about 100 MPa. In another embodiment of the invention, it is desirable that the multicomponent fibers exhibit a tensile stress value of less than about 150 MPa, advantageously less than 125 MPa, suitably less than 100 MPa.

The biodegradable nonwoven material of the present invention comprises disposable absorbent products such as diapers, adult incontinence products, and bed pads; menstrual means such as sanitary napkins and tampons; and wipes, masks, wounds. It is suitable for use in disposable products such as dressings and other absorbent products such as surgical capes or sterile cloth. Accordingly, in another aspect, the present invention relates to disposable absorbent products that include multi-component fibers.

In one embodiment of the invention, the multicomponent fibers are formed into a fibrous matrix for incorporation into a disposable absorbent product. The fibrous matrix may take the form of, for example, a fibrous nonwoven web. The fibrous nonwoven web may be made from fibers prepared entirely from the multicomponent fibers of the present invention, or may be blended with other fibers. The length of fiber used will vary depending on the particular end use intended. If the fiber is to be degraded in water, for example in a toilet, its length is conveniently kept at about 15 millimeters or less.

In one embodiment of the invention, a disposable absorbent product is provided, but generally
The disposable absorbent product comprises a composite structure including a liquid-permeable top sheet, a fluid-trapping layer, an absorbent structure, and a liquid-impermeable backsheet, the liquid-permeable top sheet, the fluid-trapping layer, or the liquid-impermeable layer. At least one of the functional backsheets comprises the nonwoven material of the present invention. In certain instances, it may be advantageous for all three of the top sheet, fluid acquisition layer, and back sheet to include the nonwoven material of the present invention. In another embodiment, the disposable absorbent product may generally consist of a composite structure such as a liquid-permeable topsheet, an absorbent structure, and a liquid-impermeable backsheet, a liquid-permeable topsheet or a liquid. At least one of the impermeable backsheets comprises the nonwoven material of the present invention.

In another embodiment of the present invention, the nonwoven material may be prepared on a spunbond line. The resin pellet containing the above-mentioned thermoplastic material is molded and dried in advance. After that, they are fed into a single extruder. The fibers can be drawn by a fiber drawing device or a pneumatic drawing device, fed onto a forming wire mesh and thermally bonded. But,
Other methods and preparation techniques can also be used. Exemplary disposable absorbent products are US Pat. No. 4,710,187, US Pat. No. 4,762,521, US Pat. No. 4,770,656, and US Pat.
, 798,603, the disclosures of which are incorporated herein by reference. In general, absorbent products and structures according to all aspects of the invention undergo multiple releases of bodily secretions at the time of use. Therefore, it is desirable that the absorbent products and structures be capable of absorbing multiple releases of bodily fluids to which the absorbent products and structures are exposed during use. Generally, the release is done at predetermined time intervals.

Test Method Melting Temperature The melting temperature of a material is measured using differential scanning calorimetry. To determine the melting temperature, Thermal Analyst 2200 analysis software (
A differential scanning calorimeter named Thermal Analyst 2910 Differential Scanning Calorimeter, used in combination with the version 8.10) program and equipped with a liquid nitrogen chiller. These are T.S., located in Newcastle, Delaware. A. Available from Instruments. The material samples tested were either in the form of fibers or resin pellets. It is preferable to use tweezers or other equipment, rather than handling the material sample directly by hand, so as not to bring in anything that may give erroneous test results. Material samples were cut for fibers and placed in aluminum pans for resin pellets and weighed with an analytical balance to an accuracy of 0.01 milligrams. If necessary, the material samples were covered and clamped on the dish.

The differential scanning calorimeter was calibrated using an indium metal standard and baseline correction performed as described in the manual for the differential scanning calorimeter. A material sample was placed in the test chamber of a differential scanning calorimeter for testing and an empty pan was used as a reference. All tests were performed on a test chamber with a 55 cubic centimeters / minute nitrogen (industrial grade) purge. The heating and cooling program begins with the chamber equilibrating to -40 ° C, then 20 ° C to 200 ° C.
° C / min heating cycle, followed by -20 ° C / min cooling cycle to -40 ° C,
It was then a two cycle test followed by another heating cycle of 20 ° C / min up to 200 ° C.

The test results were evaluated using an analytical software program. Here, the glass transition temperature (Tg) of the inflection point, endothermic and exothermic peaks are determined and quantified. The glass transition temperature is determined as the area on the line where a distinct change in slope occurs, after which the melting temperature is measured using automatic inflection point calculation.

Apparent Viscosity Used in combination with WinRHEO (version 2.31) to evaluate the apparent clay flow properties of material samples, Gottfert Rheograp.
A capillary rheometer named h 2003 Capillary Rheometer was used. These are Gottfert c located in Rock Hill, South Carolina.
It is available from Ompany. The capillary rheometer device was equipped with a 2000 bar pressure transducer and a circular hole capillary base with a flow of 30 mm length, 30 mm effective length, 1 mm diameter, 0 mm height, 180 ° angle.

If the material sample used is or is known to be water-sensitive, it is in a vacuum oven above the glass transition temperature, ie 55 or 60 for poly (lactic acid) material. C. and above under a vacuum of at least 15 inches of mercury at least 16 hours using a nitrogen gas purge of 30 standard cubic feet per hour at least.

[0059]   Once the instrument is operational and the pressure transducer is calibrated, the material sample is
Resin is loaded incrementally into the ram to ensure consistent melting during testing.
Was frequently packed into the column with a push rod. After loading the material sample, the material sample is
A 2 minute melt time was set before each test to allow complete melting at the test temperature
. The capillary rheometer automatically acquires the data points, 50, 100, 20
Seven apparent shear rates (seconds) of 0, 500, 1000, 2000, and 5000. ^-1 ) The apparent viscosity (in Pascal-seconds) was measured. Examine the resulting curve
In that case, it was important that the curve was relatively smooth. Due to the air in the column
And if it deviates significantly from the overall curve from one point to another, the inspection
The test was repeated to confirm the results.

The resulting rheological curve of apparent viscosity against apparent shear rate is an indicator of how the material sample flows at the temperature of the extrusion process. Apparent viscosity values at shear rates of at least 1000 sec ^-1 are particularly important as they are typical conditions found in commercial fiber spinning extruders.

Molecular Weight Gas Permeation Chromatographic Analysis (GPC) is used to measure the molecular weight distribution of samples such as poly (lactic acid) polymers having a weight average molecular weight (Mw) between about 800 and about 400,000. did. The GPC set two 5 micron, 7.5 x 300 mm PL Gelmix K linear analytical columns in series. Column and detector temperature is 30 °
It was C. The mobile phase was high performance liquid chromatographic analysis (HPLC) grade tetrahydrofuran (THF). Pump speed was 0.8 milliliters / minute with an injection volume of 25 microliters. The total running time was 30 minutes. It is important to note that the new analytical column should be installed about every 4 months, the new protection column about every 1 month, and the new in-line filter about every 1 month.

Aldrich Chemical Co. A polystyrene polymer standard obtained from HPLC was a HPLC grade dichloromethane (DCM): THC (10:
90) was mixed with the solvent to give a concentration of 1 mg / mL. If the peaks do not overlap when performing chromatographic analysis, multiple polystyrene standards should be
It can be combined in one solvent. Standards with molecular weights ranging from about 687 to 400,000 were prepared. Examples of various weight average molecular weights of standard mixtures with Aldrich polystyrene are given in Standard 1 (401,340; 32,660; 2
, 727), standard 2 (45,730; 4,075), standard 3 (95,800).
12, 860), and standard 4 (184, 200; 24, 150; 680).

Next, stock test standards were prepared. First, Polysciences
Inc. (Catalog number 19245) 10 g of 200,000 molecular weight poly (lactic acid) standard obtained from (1) was dissolved in 100 ml of HPLC grade DCM using an orbital shaker (at least 30 minutes) with a glass jar with a closed lid. . The mixture was then poured onto a clean dry glass plate to evaporate the solvent and then placed in a vacuum oven preheated to 35 ° C. and dried under a vacuum of 25 mm mercury column for about 14 hours. Next, take out the poly (lactic acid) from the oven,
The film was cut into small strips. Immediately, the sample was polished using a polishing mill (with a 10 mesh screen), taking care not to stop the polishing apparatus by adding a large amount of sample. A few grams of the polished sample was stored in a dry glass jar in the dryer, while the rest of the sample was stored in a similar jar in the freezer.

Before starting each new procedure, it is important to prepare new test standards and the molecular weight is strongly influenced by the concentration of the sample, so great care should be taken in their weighing and preparation. There is a need. To prepare the test standards, 0.0800 g ± 0.0025 g of 200,000 weight average molecular weight poly (lactic acid) reference standard was weighed into a clean dry scintillation bottle. Then, using a volumetric pipette or a dedicated repipette, 2 ml of DCM was added to the bottle and the lid was tightly closed. The sample was completely thawed. If necessary, samples should be Thermolyne Roto.
Stir with an orbital shaker such as Mix (Type 51300) or similar mixer. The bottle was exposed to light at a 45 degree angle to assess whether it was melted. The bottle was swirled slowly to observe the liquid running down the glass. If the bottom of the bottle is not smooth, the sample is not completely melted. In that case, it is necessary to melt the sample for several hours. Once melted, use a volumetric pipette or dedicated repipette to remove 18 ml
THF was added and the bottle was tightly closed.

Sample preparation was started by weighing out 0.0800 g ± 0.0025 g of sample into a dry scintillation bottle (weighing and preparation should be taken with the utmost care).
Using a volumetric pipette or dedicated repipette, add 2 ml DCM to the bottle,
I closed the lid tightly. Samples were completely thawed using a method similar to the test standard preparation method described above. Then, using a volumetric pipette or a dedicated pipette,
8 ml of THF was added, and the bottle was tightly closed and mixed.

The evaluation started with a test injection of a standard preparation to test the equilibrium of the system. Once equilibrium was confirmed, the standard preparation was injected. After doing these, the test standard preparation was injected first and then the sample preparation. The test standard preparation was injected after each 7 injections of sample and at the end of the test. Care should be taken not to make more than two injections from any one of the bottles, two injections at 4.
Must be done within 5 hours.

There are four quality control parameters for evaluating test results. First, the fourth-order regression correction coefficient calculated for each standard should be 0.950 or more and 1.050 or less. Second, the relative standard deviation of the weight average molecular weight of the test standard preparation should be 5.0 percent or less. Third, the average weight average molecular weight of the test standard preparation injectate is 1 of the weight average molecular weight in the first test standard preparation injectate.
Must be within 0 percent. Finally, the lactide reactivity for the 200 microgram / milliliter (μg / mL) standard injection is recorded on the SQC data chart. Using the decision line of the chart, the reactivity should be within the defined SQC parameters.

Molecular statistics are calculated based on calibration curves obtained from polystyrene standard preparations and constants for poly (lactic acid) and polystyrene in THF at 30 ° C. These were polystyrene (K = 14.1 × 10 ⁵ , alpha = 0.700) and poly (lactic acid) (K = 54.9 × 10 ⁵ , alpha = 0.669).

Heat Shrinkage of Fibers The equipment required to measure heat shrinkage was a convection oven (Thelco type 160DM laboratory oven available from Precision and Scientific Inc. of Chicago, Ill.), 0.5 grams ( +/- 0.06
Gram) sinker weight, 1 inch binder clip at least 1 inch square, masking tape, graph paper, foam poster board or graph paper and equivalent substrate to which the sample is applied. The convection oven must be able to achieve temperatures of about 100 ° C.

Each fiber sample is melt-spun in each spinning state. Generally, 30 fiber bundles are preferred and mechanically stretched to advantageously obtain a jet stretch ratio of 224 or higher. Only fibers with the same jet stretch ratio can be compared for heat shrinkage. The fiber jet stretch ratio is the ratio of the draw roll speed divided by the linear extrusion speed (distance / hour) of the molten polymer exiting the spinneret. Usually, the spun fiber is wound on a bobbin using a winder. If the wound fiber was not a 30-fiber bundle, it was separated into 30-fiber bundles and cut into 9-inch lengths.

The graph paper was attached to the post board with tape, and one end of the graph paper was aligned with the end of the post board. A tape was attached to one end of the fiber bundle within 1 inch from the end. The end with the tape was clipped to the end of the postboard, but the end of the postboard held the fiber bundle in place while the end of the clip was on one horizontal line of the graph paper. It was the end that matched the graph paper well (the end where the tape was attached is slightly visible as it is fixed under the clip). The other end of the fiber bundle was arranged parallel to the vertical line of the graph paper. A 0.5 gram sinker was then sandwiched around the fiber bundle, 7 inches down from where the fiber was clipped. The mounting process was repeated for each experiment.
Usually, three experimental objects can be attached at one time. Graph paper can be marked to indicate the initial position of the sinker. The sample was placed in an oven at about 100 ° C, but the sample was hung vertically to avoid contact with the postboard. At time intervals of 5, 10, and 15 minutes, new positions of the sinkers were quickly marked on the graph paper and the samples were returned to the oven.

After the test was completed, the post board was removed and a 1/16 scale ruler was used.
The distance between the initial position (the clip held the fiber) and the 5, 10, and 15 minute marks was measured. Three experiments per sample are preferred. Calculate mean, standard deviation, and percent shrinkage. Percent shrinkage is (initial length-measured length) divided by the initial length and multiplied by 100. As described in the examples herein and used throughout the claims, the heat shrinkage value represents the total heat shrinkage exhibited by the fiber sample at about 100 ° C. for a time of about 15 minutes.

[0073] The contact angle this device, DCA-322 Dynamic Contact Angle
Includes Analyzer and WinDCA (version 1.02) software, which are ATI-CAHN Inst, located in Madison, Wisconsin.
documents, Inc. Available from. The test was performed with a balance stirrup attached on the "A" loop. Calibration should be done monthly for motors and daily for balances (using 100 mg mass) as directed in the manual.

The thermoplastic composition was spun into fibers and a free falling sample (zero jet stretch) was used to measure the contact angle. Care should be taken to avoid touching the fiber as much as possible to ensure that contamination is kept to a minimum throughout the fiber preparation. The fiber sample was attached to the wire hanger with scotch tape so that 2-3 cm of fiber extended beyond the end of the hanger. The fiber sample was then cut with a razor such that about 1.5 cm extended beyond the end of the hanger. An optical microscope was used to measure the average diameter along the fiber (3-4 measurements).

The sample on the wire hanger was suspended from the balance stirrup of loop “A”. The immersion liquid was distilled water and was replaced for each sample. The test was initiated by entering the sample parameters (ie fiber diameter). The stage was advanced at 151.75 microns / second until a zero submersion depth was detected where the fibers contacted the surface of the distilled water. From zero submersion depth, the fibers were advanced 1 cm into the water, held for 0 seconds and then immediately retracted 1 cm. The automatic analysis of contact angles performed by the software measures advancing and receding contact angles of fiber samples based on the same standard calculations as the manual. A contact angle of 0 or <0 indicates that the sample became totally wettable. Five tests were run on each sample and a statistical analysis on the mean, standard deviation, and coefficient of change was calculated. As described in the examples herein and used throughout the claims, the advancing contact angle value represents the advancing contact angle of distilled water on a fiber sample measured according to the test method described above. Similarly, as described in the Examples herein and used throughout the claims, the receding contact angle value represents the receding contact angle of distilled water on a fiber sample measured according to the test method described above. .

Fluid Uptake and Reflux Assessment (FILE) The Fluid Uptake and Reflux Assessment (FILE) test was used to measure the absorption time and reflux of personal care products. Master-Flex Digi-St
The artic Automatic Dispensing system was supplied with a small amount of saline solution colored with FD & C blue dye, set to give a release of 80 mL and administered several times to remove air bubbles. Product samples, baby care diapers, were prepared without elastic rubber for easy flattening. Two 3.5 inch x 12 inch absorbent paper samples were weighed. The papers were placed on top of FIFE board, a simple board with a 3 "x 6" raised platform in the center. The absorbent paper was positioned to extend longitudinally along either side of the raised platform. The diaper was then carefully positioned with the top sheet facing upwards so that there were no visible wrinkles in the non-woven top sheet and the area receiving the release was centered on the raised platform. Next, a second FIFE board was placed on the product. This equipment is composed of a flat plate material in which hollow cylinders intersect each other, and projects only from the upper surface of the plate material. The circular area, which was formed where the cylinder intersected the plane of the plate, was hollow. The inner diameter of the cylinder was 5.1 centimeters. A funnel with a short end and a diameter of 7 mm was placed in the cylinder. The fluid was then pumped directly into the funnel. The uptake time was recorded with a stopwatch from the time the fluid reached the funnel to the time the fluid disappeared at the sample surface. The absorbent paper is checked for leaks in the product, and if leaked, the absorbent paper can be weighed to determine the amount of fluid leakage. No leaks occurred in the test described. After about 1 minute, the second release was performed in a similar manner. The third release was performed again and the time was measured by the same method. If desired, the procedure for measuring the amount of fluid flowing back when the product is under pressure may be followed. In this case, only the capture rate is recorded.

Transdermal Water Loss (TEWL) The Transdermal Water Loss (TEWL) armband test was used to measure changes in skin hydration as a result of using the product. Servo Med Evapo
Lower evaporation values indicate that the product promotes dryness of the skin, as measured by rimeter. In practice, this test records differences in evaporation values.
The water evaporation rate was measured before the test, and the test was performed immediately. The difference between these numbers gives the TEWL value as recorded in the test results. A lower TEWL value means that the product has better breathability to the skin.

Baby care diaper products were prepared manually without elastic members or ears. Although the basic structure of the diaper is the same, one control diaper is made entirely of standard material and the other diaper is made entirely of standard material except for the top sheet made of biodegradable nonwoven fabric. It was The target area of release was marked with an oily marker on the outside of the product. All tests were conducted in a controlled environment of 72 ± 4 ° F. and 40 ± 5% relative humidity. The subject was a carefully selected adult female, who had no conditions that could change the outcome of this study.

The test subject was 10 g / m ² / m in Servo Med Evaporator.
Relaxed in a controlled environment until a stable baseline reading of less than hr was obtained. These measurements were performed on the subject's forearm. Masterflex Di
The gi-Static batch / dispensing pump was equipped with a silicone tube in the pump head and connected to the dispensing neoprene tube with a jaw fitting. The tip of the dispensing neoprene tube was attached to the subject's forearm and the product was attached to the forearm so that the target release area was directly above the tube opening. The product was taped, but the tape was wrapped around the diaper to avoid contact with the skin. Next, 60 ml of salt water was discharged into the diaper three times at intervals of 45 seconds, and the tube was removed. The product was further secured with an extensible net, but the subject had to sit for 1 hour. The product was removed after 60 minutes of wear and then read using the Evaporometer in the same forearm area as the baseline reading for 2 minutes, every 1 second. The test results recorded are the difference between the 1 hour reading and the baseline reading.

Examples In the following examples, various materials were used as building blocks to form thermoplastic compositions and multicomponent fibers. The names and various properties of these materials are listed in Table 1.
Listed in. Heplon A10005 poly (lactic acid) (PLA) polymer is available from Chronopol Inc. of Golden, Colorado. Obtained from. Polybutylene succinate (PBS) is a product of Showa H, located in Tokyo, Japan.
IGH POLYMER Co. , Ltd. From Bionolle 1020 polybutylene succinate. Long-chain branched polybutylene succinate (PBS) is an S-based product located in Tokyo, Japan.
howa Highpolymer Co. , Ltd. From Biolele1
Obtained under the name of 093 polybutylene succinate. The material used as a wetting agent throughout this example was obtained from Petrolite Corporation of Tulsa, Okla. Under the name UNITHOX® 480 ethoxylated alcohol and has a number average molecular weight of about 2250, about 80 weight percent. And an HLB value of about 16.

Table 1

Examples 1-5 Thermoplastic compositions were prepared using varying amounts of poly (lactic acid) polymer, polybutylene succine, and wetting agent. To prepare a particular thermoplastic composition, the various components were first dry mixed and then melt mixed in a counter-rotating twin screw extruder to intimately mix the components. In melt mixing, the shearing action of a rotary mixing screw results in partial or complete melting of the mixed components. Such conditions lead to optimum mixing and uniform dispersion of the components of the thermoplastic composition. Haake Rheocor available from Haake GmbH, Karlzoite, Germany
d 90 twin screw extruder or Br available from Brabender Instruments, South Hackensack, NJ
abender twin screw extruder (catalog number 05-96-000)
Twin screw extruders such as, or other similar twin screw extruders are suitable. The melted composition was extruded from a melt mixer and then cooled by forced air flow over the extrudate. The cooled composition was then pelletized for conversion into fibers.

The conversion of these resins into fibers and non-woven fabrics was carried out on a spinning line in the plant equipped with an extruder with a diameter of 0.75 inches, the extruder being 24: 1 L: D (length: diameter). The ratio screw and the three heating zones that flow into the transfer pipe from the extruder to the spin pack, which constitutes the fourth heating zone, are the Koch Engineering company located in New York, NY.
Inc. Including a 0.62 inch diameter KOCH® SMX static mixer unit, available from the company, which then enters the spinning head (fifth heating zone) and has a large number of small holes through which molten polymer is extruded. Pass through the plate. The spinning plate used herein had 15 holes, each hole being 20 mils in diameter.
The fibers are quenched with air at a temperature of 13 ° C to 22 ° C, drawn by mechanical drawing rolls and conveyed to or collected by a winding unit for collection, or a spunbond forming and bonding fiber drawing unit. Transport via other auxiliary equipment for previous heat curing or other processing.

The polymer was converted to a spunbond nonwoven material and made using 14 ″ and 20 ″ fiber spinning lines. Single component fibers were produced in a single extruder and the fibers were prepared by drawing with a fiber drawing unit (FDU). The web was then thermally bonded in-line with a wire mesh bonding pattern.

The wettability of the example nonwoven materials was quantified using contact angle measurements, with a small contact angle indicating a highly wettable material. The measured contact angle is WinDC
Chan DCA-322 D with A version 1.02 analysis software
It was performed by a dynamic Contact Angle Analyzer.
The resin was spun into free-falling fibers and used in this measurement. Care was taken to avoid touching the fibers as much as possible to help prevent contamination. A single fiber, about 3 cm long, was taped to a thin wire hanger so that 1.5 cm of the fiber extended beyond the end of the hanger. Fiber diameter was measured using an optical microscope and entered into a computer. Also, other parameters such as the fiber shape used and the surface tension of the liquid were entered into the software. Distilled water was used as the liquid for these examples.

The sample was hung on an “A” loop balance, under which a small beaker of water was placed so that the ends of the fiber were almost in contact with the liquid surface. The stage allowed the fibers to reach 151.75 until a submersion depth of zero was detected when the fibers contacted the surface of the distilled water.
Micron / sec Hold forward. From zero submersion depth, the fibers were advanced 1 cm into the water, held for 0 seconds, and then immediately retracted 1 cm. Data analysis was performed automatically by the software. Five tests were carried out on each sample and the average values for the advancing and receding contact angles were calculated.

Test results for advancing and receding contact angles are shown in Table 2. Advancing contact angle is a measure of how a material interacts with a fluid upon initial contact with the liquid. The receding contact angle is
A measure of how a material behaves during multiple releases in a liquid or high humidity environment. The formulations included in the present invention produced highly wettable fibers.

Contact angle data

Table 3 shows the results of testing fluid treatment properties of the nonwoven material of the present invention. As shown in the table, the uptake time of the nonwoven material of the present invention is very short compared to the control surfactant treated polypropylene spunbond liner. For subsequent release, the surfactant will begin to flow out of the treated diaper liner, leading to very long uptake times. The permanently hydrophilic surface of the nonwoven material of the present invention maintains its wettability permanently, so
Even when the number of uptakes increases, it remains much shorter than the uptake time of the polypropylene liner. Further, liners made with the nonwoven material of the present invention have less backflow than control liners. This is significant because under pressure only a very small amount of liquid will flow back to the user side of the liner, keeping the skin dry.

One of the most important tests for skin dryness is how the material behaves in the TEWL test, which measures skin dryness when covered with a diaper that has undergone saline release. . The low TEWL values exhibited by the non-woven materials of the present invention indicate improved dryness of the skin.

Table 3 Fluid treatment characteristics

Those skilled in the art will appreciate that the present invention is capable of numerous modifications and variations without departing from the scope of the invention. Accordingly, the foregoing detailed description and examples are illustrative and do not limit the scope of the invention as claimed.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) A61F 13/511 D01F 1/10 4L047 13/514 6/92 301B 13/53 308A 13/551 A61F 13/18 310Z B32B 5/26 320 27/36 303 // D01F 1/10 383 6/92 301 A41B 13/02 D 308 EF B (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES , FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE, TR), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR , NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), EA (AM AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, CA, CH, CN, CR, CU, CZ, DE, DK, DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP , KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Wartheim Bridget Sea Wisconsin 54914 Appleton West Wisconsin Aveni Over 1515 apartment instrument 1 F term (reference) 3B029 BA04 BA18 BB07 BC07 4C003 AA11 BA06 CA04 HA04 4C098 AA09 CC03 DD10 DD23 DD26 4F100 AH02A AH02B AH02D AK41A AK41B AK41D AL05A AL05B AL05D AR00C AR00D BA03 BA10A BA10B CA30A CA30B CA30D DG15A DG15B DG15D GB66 GB72 JB05A JB05B JB05D JC00A JC00B JC00D JD05A JD05B JD05D JD15C JL04 YY00A YY00B YY00D 4L035 AA05 BB31 BB56 EE05 EE20 FF01 FF04 FF05 JJ05 KK05 4L047 AA21 AB02 AB02 A02 AB02 A02

Claims (37)

[Claims] 1. A poly (lactic acid) polymer of greater than 0 weight percent and less than 100 weight percent; and b) a polybutylene succinate polymer, polybutylene succinate polymer of greater than 0 weight percent and less than 100 weight percent. A polymer selected from the group consisting of adipate polymers, and mixtures of such polymers, and c) about 10 weight percent greater than 0 weight percent up to about 15 weight percent.
To a biodegradable nonwoven material comprising a plurality of fibers of a thermoplastic composition comprising a wetting agent exhibiting a hydrophilic-hydrophobic balance ratio between about 40 and about 40, all weight percentages being equal to the above The poly (lactic acid) polymer present in the plastic composition; polybutylene succinate polymer, polybutylene succinate,
A biodegradable non-woven material, characterized in that it is based on the total weight of the adipate polymer, and the polymer selected from the group consisting of mixtures of such polymers; and the wetting agent. 2. The poly (lactic acid) polymer is from about 5 weight percent to about 9 weight percent.
The polymer, present in a weight of up to 5 weight percent, selected from the group consisting of polybutylene succinate polymers, polybutylene succinate adipate polymers, and mixtures of the polymers is from about 5 weight percent to about 9 weight percent.
The biodegradable product of claim 1, wherein the wetting agent is present in a weight of up to 5 weight percent and the wetting agent is present in a weight of between about 0.5 weight percent and about 15 weight percent. Non-woven material. 3. The poly (lactic acid) polymer is present in a weight between about 10 weight percent and about 90 weight percent, polybutylene succinate polymer, polybutylene succinate adipate polymer, and such polymers. The polymer selected from the group consisting of a mixture of about 10 weight percent to about 90 weight percent, and the wetting agent weight of between about 1 weight percent to about 13 weight percent. The biodegradable nonwoven material of claim 2, wherein the biodegradable nonwoven material is present in 4. The biodegradable nonwoven material of claim 1, wherein the humectant exhibits a hydrophilic-hydrophobic balance ratio of between about 10 and about 20. 5. The biodegradable nonwoven material of claim 1, wherein the wetting agent is an ethoxylated alcohol. 6. The poly (lactic acid) polymer is present in a weight between about 75 weight percent and about 90 weight percent, polybutylene succinate polymer, polybutylene succinate adipate polymer, and mixtures of the polymers. 2. The polymer of claim 1, wherein the polymer selected from the group consisting of is present in a weight of between about 5 weight percent and about 20 weight percent, and the wetting agent is an ethoxylated alcohol. Biodegradable non-woven material. 7. A poly (lactic acid) polymer in a weight greater than 0 weight percent and less than 100 weight percent, and b) a polybutylene succinate polymer, polybutylene succinate in a weight weight greater than 0 weight percent and less than 100 weight percent. A polymer selected from the group consisting of nate-adipate polymers, and mixtures of such polymers, and c) about 10 weight percent greater than 0 weight percent up to about 15 weight percent.
A biodegradable nonwoven material comprising a plurality of multi-component fibers prepared from a thermoplastic composition comprising: a wetting agent having a hydrophilic-hydrophobic balance ratio between about 40 and about 40, all weights being Percentages are present in the thermoplastic composition of the poly (lactic acid) polymer; polybutylene succinate polymer, polybutylene succinate.
Based on the total weight of the adipate polymer and the polymer selected from the group consisting of mixtures of such polymers; and the wetting agent, further wherein the multicomponent fiber has an advancing contact angle of less than about 80 and an advancing contact angle of less than about 60. A biodegradable nonwoven material characterized by exhibiting a receding contact angle of less than. 8. The poly (lactic acid) polymer is from about 5 weight percent to about 9 weight percent.
The polymer, present in a weight of up to 5 weight percent, selected from the group consisting of polybutylene succinate polymers, polybutylene succinate adipate polymers, and mixtures of the polymers is from about 5 weight percent to about 9 weight percent.
The biodegradable product of claim 7, wherein the wetting agent is present in a weight of up to 5 weight percent and the humectant is present in a weight of between about 0.5 weight percent and about 15 weight percent. Non-woven material. 9. The biodegradable nonwoven material of claim 7, wherein the wetting agent exhibits a hydrophilic-hydrophobic balance ratio of between about 10 and about 20. 10. The biodegradable nonwoven material of claim 7, wherein the wetting agent is an ethoxylated alcohol. 11. The biodegradable nonwoven material of claim 7, wherein the multicomponent fibers exhibit an advancing contact angle of less than about 75 and a receding contact angle of less than about 55. 12. The biodegradable nonwoven material of claim 11, wherein the difference between the advancing contact angle and the receding contact angle is less than about 30. 13. The biodegradable nonwoven material of claim 7, wherein the multi-component fiber exhibits a heat shrinkage value of less than about 15. 14. The poly (lactic acid) polymer is present in a weight of between about 75 weight percent and about 90 weight percent, polybutylene succinate polymer, polybutylene succinate adipate polymer, and mixtures of the polymers. Wherein the polymer selected from the group consisting of is present in a weight of between about 5 weight percent and about 20 weight percent, the wetting agent is an ethoxylated alcohol, and the advancing contact angle and the receding contact angle are 9. The biodegradable nonwoven material of claim 7, wherein the difference between the two is less than about 30 and the multi-component fiber exhibits a heat shrinkage value of less than about 15. 15. A biodegradable non-woven material comprising a plurality of multi-component fibers, said multi-component fibers being prepared from a plurality of components, wherein one of the components is: a) greater than 0 weight percent and greater than 100. From less than 1 weight percent poly (lactic acid) polymer, and b) from more than 0 weight percent and less than 100 weight percent polybutylene succinate polymer, polybutylene succinate adipate polymer, and mixtures of such polymers. A polymer selected from the group consisting of: c) about 10 weight percent greater than 0 weight percent up to about 15 weight percent;
A biodegradable nonwoven material comprising an unreacted thermoplastic composition comprising a wetting agent exhibiting a hydrophilic-hydrophobic balance ratio between 1 and about 40, wherein all weight percentages are from the thermoplastic The poly (lactic acid) polymer present in the composition; polybutylene succinate polymer, polybutylene succinate,
Based on the total weight of the adipate polymer, and the polymer selected from the group consisting of mixtures of such polymers; and the wetting agent, further wherein the plurality of multicomponent fibers comprises an unreacted thermoplastic composition. A biodegradable non-woven material, characterized in that it is arranged on the surface of the multicomponent fibers. 16. The poly (lactic acid) polymer is present in a weight of between about 5 weight percent and about 95 weight percent, polybutylene succinate polymer, polybutylene succinate adipate polymer, and mixtures of the polymers. Wherein the polymer selected from the group consisting of is present in a weight of between about 5 weight percent and about 95 weight percent, and the wetting agent comprises a weight of between about 0.5 weight percent and about 15 weight percent. 16. The biodegradable nonwoven material of claim 15, wherein the biodegradable nonwoven material is present in 17. The biodegradable nonwoven material of claim 15, wherein the humectant exhibits a hydrophilic-hydrophobic balance ratio of between about 10 and about 20. 18. The biodegradable nonwoven material of claim 15, wherein the wetting agent is an ethoxylated alcohol. 19. The biodegradable nonwoven material of claim 15, wherein the multicomponent fibers exhibit an advancing contact angle of less than about 75 and a receding contact angle of less than about 55. 20. The biodegradable nonwoven material of claim 19, wherein the difference between the advancing contact angle and the receding contact angle is less than about 30. 21. The biodegradable nonwoven material of claim 15, wherein the multi-component fiber exhibits a heat shrinkage value of less than about 15. 22. The poly (lactic acid) polymer is present in a weight of between about 75 weight percent and about 90 weight percent, polybutylene succinate polymer, polybutylene succinate adipate polymer, and mixtures of the polymers. Wherein the polymer selected from the group consisting of is present in a weight between about 5 weight percent and about 20 weight percent, the wetting agent is an ethoxylated alcohol, and the advancing contact angle and the receding contact angle are 16. The difference between the two is less than about 30 and the multicomponent fiber exhibits a heat shrinkage value of less than about 15.
A biodegradable non-woven material according to. 23. A biodegradable nonwoven material comprising a plurality of multi-component fibers, wherein the multi-component fibers exhibit an advancing contact angle of less than about 80 and a receding contact angle of less than about 60. Biodegradable non-woven material. 24. An absorbent product comprising a liquid permeable top sheet, an absorbent structure, and a liquid impermeable back sheet, wherein at least one of the liquid absorbent top sheet or the liquid impermeable back sheet is An absorbent product comprising the biodegradable nonwoven material of claim 1. 25. The absorbent product of claim 24, wherein the liquid absorbent topsheet and liquid impermeable backsheet comprise the biodegradable nonwoven material. 26. The absorbent product of claim 23, further comprising a fluid acquisition layer. 27. The absorbent product of claim 26, wherein the liquid-permeable topsheet, the fluid-trapping layer, and the liquid-impermeable backsheet comprise the biodegradable nonwoven material. . 28. An absorbent product comprising a liquid permeable top sheet, an absorbent structure, and a liquid impermeable backsheet, wherein at least one of said liquid absorbent top sheet or liquid impermeable backsheet. An absorbent product comprising the biodegradable nonwoven material of claim 7. 29. The liquid permeable top sheet, fluid acquisition layer, and liquid impermeable back sheet comprise the biodegradable nonwoven material.
The absorbent product according to item 8. 30. The absorbent product of claim 28, wherein the liquid absorbent top sheet and liquid impermeable back sheet comprise the biodegradable nonwoven material. 31. The absorbent product of claim 28, further comprising a fluid capture layer. 32. The absorbent product of claim 31, wherein the liquid permeable top sheet, the fluid acquisition layer, and the liquid impermeable back sheet comprise the biodegradable nonwoven material. . 33. An absorbent article comprising a liquid permeable top sheet, an absorbent structure, and a liquid impermeable back sheet, wherein at least one of said liquid absorbent top sheet or liquid impermeable back sheet. An absorbent product comprising the biodegradable nonwoven material of claim 15. 34. The absorbent product of claim 33, wherein the liquid absorbent top sheet and the liquid impermeable back sheet comprise the biodegradable nonwoven material. 35. The absorbent product of claim 33, wherein the liquid absorbent topsheet and liquid impermeable backsheet comprise the biodegradable nonwoven material. 36. The absorbent product of claim 33, further comprising a fluid trapping layer. 37. The absorbent product of claim 36, wherein the liquid-permeable topsheet, the fluid-trapping layer, and the liquid-impermeable backsheet comprise the biodegradable nonwoven material. .