HK1166027A1 - Absorbent article comprising an encapsulated plant extract exhibiting an insecticidal effect - Google Patents

Abstract

The present invention relates to a disposable absorbent article in which an encapsulated natural plant extract exhibiting an insecticidal effect is applied thereto. In particular, the present invention relates to a disposable absorbent article comprising a liquid permeable top sheet, an absorbent core, and a liquid impermeable back sheet, characterized in that insecticidal microcapsules prepared by microencapsulating an extract of natural plants providing an insecticidal effect are applied thereto, where the plant is selected from the group consisting of cinnamon, rosemary, lavender, mint, eucalyptus, and mixtures thereof. Since the disposable absorbent article according to the present invention comprises an extract of natural plants in an encapsulated form that naturally provide an insecticidal effect while being nontoxic to the human body, it can effectively and consistently prevent harmful insects from invading the article during distribution and storage.

Description

Absorbent article comprising encapsulated plant extracts exhibiting an insecticidal effect

Technical Field

The present invention relates to a disposable absorbent article comprising microcapsules of deinsectization, in which an extract of at least one natural plant selected from the group consisting of cinnamon, rosemary, lavender, mint, eucalyptus, is microencapsulated.

Background

Disposable absorbent articles refer to products that absorb body fluids discharged in response to various physiological events, such as diapers, toilet training pants, adult incontinence garments, absorbent undergarments, feminine care products, care pads, and the like. With respect to the performance characteristics of these disposable absorbent articles, the degree of absorption and the rate of absorption of bodily fluids excreted by the physiological reaction are important considerations. Due to the development of super absorbent polymers and the like, there have been remarkable improvements in absorbency and absorption rate.

In addition to being absorbent, another performance characteristic required of disposable absorbent articles is the ability to prevent skin problems that may arise from the use of these articles when bodily fluids are excreted. Further, since the absorbed body fluid often produces unpleasant odors for absorption by the article, research into a method of applying a fragrance or a deodorant to the absorbent article to remove such odors is actively conducted. There is also an increasing need to develop methods to effectively prevent the intrusion of larvae or adults into disposable absorbent articles, as the intrusion of pests during the distribution and storage of disposable absorbent articles can cause deterioration of the quality of the disposable absorbent articles, as well as hygiene problems.

The most common pests that attack disposable absorbent articles during distribution and storage typically include mosquitoes, rice weevils (rice weevils), grain thieves (cadelle beeters), black shell moth larvae (Indian molar larvae), fungi or bacteria such as Penicillium islandicum, and the like. After the excreta is infiltrated and discharged, these vermin rapidly grow on the surface or inside of the disposable absorbent article, thereby deteriorating the quality of the disposable absorbent article.

In order to control the above-mentioned pests, fumigants such as methyl bromide, aluminum phosphide, nitrochloroform, etc. can be used as insecticides, but these are synthetic organic insecticides, which have many problems including toxicity, harmful effects on the human body, increased resistance to various types of pests, etc. To solve these problems associated with synthetic organic insecticides, many attempts have been made to use vegetable oils extracted from natural materials as insect repellents. Many plant extracts and vegetable oils have been reported to exhibit ovicidal, insect-repellent and insecticidal effects against a variety of pests in stored grains. For example, oils of Acorus calamus (sweet flag) have been reported to have bactericidal effects on red bean weevil, rice worm and khapra dominica.

Compositions mainly composed of vegetable ingredients, which relate to representative technologies for controlling pests, include U.S. patent No.4,455,304, which discloses a composition for vermin-exterminable animals and a method for using the same, in which vegetable oils extracted from pepper and garlic are used as active ingredients thereof. Further, U.S. patent No.4,440,783 discloses a composition for repelling animals, in which isothiocyanate (salt) and lemon oil are effective components. Further, WO 99/22751 discloses a method of using pepper extract, allyl isothiocyanate (salt), and lemon oil in combination instead of methyl bromide as a soil treatment agent, an insecticide, a commercial fumigant, and a building fumigant. In addition, a technique relating to a food preservative, a film, and the like utilizing the antibacterial effect of allyl isothiocyanate, which is a main component of horseradish oil and mustard oil, is also disclosed. Although a folk practice for controlling pests has been studied using garlic cloves, pepper, charcoal, etc. put in storage containers such as rice-holding containers for the purpose of preserving the quality of stored grains, the control of pests is not so good.

Japanese patent laid-open publication No. 6-38678 discloses an exemplary product containing a vegetable oil component-based preparation as an improvement over the above folk practice, that is, using a breathable container made of synthetic resin containing an allicin component extracted from garlic and a capsaicin (capcin) component extracted from pepper as a rice preservative. However, the above vegetable oils are volatile and exhibit an insecticidal effect mainly by fumigation of volatile insecticidal components. The vegetable oil has a problem of non-persistent pesticidal effect due to the active ingredients being vigorously volatilized in a very short time. Therefore, there is a high necessity for a formulation capable of maintaining a long-lasting pesticidal effect by suppressing the rapid volatilization of the above vegetable oil and adjusting the release rate.

Previously, pest control has been mainly focused on distribution and storage of agricultural products, and there has been no report on an absorbent article for direct contact with human body, which additionally has an insecticidal effect for the purpose of controlling pests.

Disclosure of Invention

Technical problem

Therefore, there is a need to develop a preparation capable of effectively preventing the invasion of insect pests into disposable absorbent articles while continuously maintaining the pesticidal effect of natural plant extracts having advantages of being harmless to humans and being environmentally friendly.

Technical scheme

The present inventors have sought to develop a human-friendly and environmentally friendly method of preventing intrusion of larvae or adults into disposable absorbent articles during distribution and storage. Accordingly, the inventors have found that a disposable absorbent article comprising microcapsules encapsulating extracts of natural plants exhibiting an insecticidal effect, such as cinnamon, rosemary, lavender, mint, eucalyptus (leaf), and the like, is capable of effectively and continuously preventing larvae such as shell powder moth from invading the disposable absorbent article during distribution and storage, without being toxic to the human body.

Accordingly, it is an object of the present invention to provide a disposable absorbent article comprising an encapsulated natural plant extract which is harmless to the human body and can continuously exhibit an insecticidal effect, and is capable of effectively preventing invasion of larvae or adults into the article during distribution and storage of the article.

In order to achieve the above objects, there is provided a disposable absorbent article comprising a liquid-impregnated upper sheet, an absorbent core, and a liquid-impermeable lower sheet (or back sheet), characterized in that an extract of at least one natural plant selected from the group consisting of cinnamon, rosemary, lavender, mint, and eucalyptus is microencapsulated and applied to the absorbent article as pest control microcapsules.

Advantageous effects

According to the present invention, a disposable absorbent article containing microencapsulated plant extracts, which naturally exhibit an insecticidal effect and are harmless to the human body, can continuously provide a strong insecticidal effect, and thus can effectively prevent insect pests from invading the disposable absorbent article during distribution and storage thereof, which may occur.

Drawings

Fig. 1 shows photographs of experimental results illustrating the insect-repellent effect of the disposable diaper comprising the microencapsulated natural plant extract of the present invention.

Detailed Description

The present invention provides a disposable absorbent article comprising an encapsulated natural plant extract that exhibits an insecticidal effect.

Specifically, the present invention provides a disposable absorbent article comprising a liquid-impregnable upper sheet, an absorbent core, and a liquid-impregnable lower sheet (or back sheet), characterized in that an extract of at least one natural plant selected from the group consisting of cinnamon, rosemary, lavender, mint, and eucalyptus is microencapsulated and applied to the pesticidal microcapsules of the disposable absorbent article.

Natural plants having an insecticidal effect suitable for use in the present invention include, for example, cinnamon, rosemary, lavender, peppermint, and eucalyptus.

Cinnamon (cinnamon cassia) bark is the bark of evergreen trees of the Lauraceae family (Lauraceae), native to south China and Vietnam. Cinnamon (cinmamon bark) refers to the bark of the tree, while cassia twig (cinmamoi ramulus) is the branch of the tree, Cinnamon bark (cinmamoiex spissus) is the bark, and Cinnamon endothelium (Cassiae cortex) is the developed bark of the old tree. Cinnamon contains 1% to 3.4% of volatile oil such as cinnamaldehyde (cinnamyl aldehyde), etc., 2% to 3% of tannic acid, viscous liquid (mucousjuice), carbohydrate, etc., and cinnamon of 5 to 6 years old is reported to contain higher levels of volatile oil. Cinnamon has been used in a variety of applications ranging from sweating drugs, antipyretics, analgesics to food seasonings. In addition, cinnamon bark is known to stimulate intestinal peristalsis and to have a preservative effect of inhibiting abnormal fermentation in the intestinal tract. In addition, cinnamon bark, which is a conventionally used ingredient in oriental medicine, is used for those having weak constitution and weak vitality on the basis of its expectation of having an immunostimulating effect, but its exact mechanism is not clear.

Korean patent laid-open No. 2000-1280 (composition for prevention and treatment of atherosclerosis comprising cinnamon bark extract of composition for prevention and treatment of atherosclerosis) korean patent laid-open No. 2001-18668 (cosmetic composition comprising cinnamon bark extract of cinnamon bark extract) and korean patent laid-open No. 2004-46309 (oral health composition comprising nanoparticulate cinnamon extract of cinnamon bark) have disclosed compositions comprising cinnamon extract, but none of the above patents describe the effect of disinsection.

Rosemary (Rosmarinus officinalis L.) is an evergreen woody plant of the family Labiatae (Labiatae), native to the mediterranean region, and is a herb useful in various types of applications, including foods, pharmaceuticals, cosmetic products, seasonings, and ornaments. The stems, flowers and leaves of rosemary can be used. In particular, the volatile oil extracted from rosemary has excellent effects on the treatment of inertness (inertia) or fatigue recovery. Rosemary is thought to prevent edema and dandruff production and stimulate hair growth. Its pungent odor activates brain cells, thereby enhancing memory and attention to effectively prevent dementia. Because of its digestion stimulating function, it is very suitable for the treatment of dyspepsia, stomachache, etc. Moreover, it is also used as an antibacterial daily necessity. Rosemary contains a volatile oil mainly composed of 1, 8-cineole, camphor, etc., and bitter components such as rosmarinic acid (rosmarinic acid), etc. It has therefore been used for pharmaceutical purposes such as stomachic, anthelmintic, anti-inflammatory agents etc. (Bisset NG, Herbaldrugs CRC press, London, 428-. Rosemary is planted in korea even as a potted herb. Rosemary oil is used in aromatherapy in various types of formulations in combination with other different types of fragrances. Meanwhile, many studies have been conducted to develop food preservatives that utilize the antioxidant properties of rosemary (Choo JJ et al, Korean J. food Culture 16: 34-138, 2003; Koleva II et al, Phytochem anal.13: 8-17, 2002). However, the pesticidal effect of rosemary is not disclosed in the above references.

Lavender (Lavendula angustifolia Mill) is a shrub half and is known to grow up to about 60cm in length. Its native region extends across Canary Islands, mediterranean regions, and india. The main components include, inter alia, a volatile oil (mainly monoterpenes) obtained by distillation from aerial parts, and caffeic acid and depsiphenolic acids obtained from its leaves. Essential oils from lavender have traditionally been used for cosmetic and therapeutic applications, such as aromatherapy. For example, in HMA Cavanagh et al, phytother. res.16: 301-308, 2002 disclose the antibacterial, antifungal, spasmolytic, sedative, and antidepressant properties of lavender oil.

In germany, research is being actively conducted on formulations using lavender flower extract for restlessness, sleep disorders, abdominal functional diseases and bloating, and as bath additives for mineral spring treatment. It has recently been found that oral administration of lavender oil can significantly ameliorate a number of disease-related symptoms in patients suffering from neurasthenia, somatization disorders, and/or post-traumatic stress disorder. Animal experiments also show that oral administration of lavender oil can significantly suppress the behavioral changes caused by stress. However, the insecticidal effect of lavender has not been reported.

Mint (Peppermint) is a perennial dicotyledonous plant of the order Lamiaceae (Lamiales), Lamiaceae (Lamiaceae). It is used in food and medicine, as a fragrance, stimulant (cordial) and bath additive, because it has a cooling effect on the skin and mucous membranes and is an effective antibacterial agent and pain reliever. Peppermint oil is known to eliminate toxic substances and thus is effective for the treatment of dermatitis, as a vaccine for the treatment of psoriasis, and for and relief of pruritus and the like. It is also used to dilate capillaries and produce a cooling effect, and is known to be effective for relieving itching, inflammation, sunburn, and the like. Further, peppermint oil is known to be effective for softening the skin and removing acne, as well as being beneficial for mental fatigue, depression, nerve collapse, and the like. However, special attention is paid to the dose of peppermint oil because it can cause a strong and exciting sensation. In particular, when peppermint oil is used in sensitive skin areas (around the eyes), special care is required because it aggravates the condition of the skin and mucous membranes. The use of peppermint oil should be restricted to women during pregnancy and lactation.

Eucalyptus globulus (Eucalyptus globulus) is an aromatic plant native to Australia. There are over 300 species of eucalyptus, most of which are grown in tropical regions. The leaves of eucalyptus contain about 2% to 7% of volatile oil, which is a colorless or straw yellow liquid with a characteristic strong odor and pungent taste, but with a refreshing taste. Eucalyptus is used in soap, wine, aromatic, medicine, etc. -especially, as antiseptic, expectorant, mouthwash, antitussive, disinfectant, etc.

The extracts of the above natural plants can be obtained by a conventional extraction method using water or lower alcohol, or commercially available extracts of each natural plant can be obtained commercially.

Conventional methods for extracting natural plants, for example, include: drying natural raw materials, and then grinding into powder; adding about 1 to 10 times, especially about 2 to 6 times, the amount of water or lower alcohol to the powder on a dry weight basis; subjecting the mixture to sonication for about 1 to 5 hours, especially about 2 to 4 hours, and heating the mixture at 20-60 ℃, especially about 30-50 ℃, followed by cooling and filtering; and concentrating the filtered product under reduced pressure using a rotary evaporator, and repeating the filtration at least twice more for the remaining residue after the filtration. Lower alcohols that can be used as the extraction solvent include methanol, aqueous methanol, ethanol, aqueous ethanol, n-propanol, isopropanol, n-butanol, or a solvent mixture thereof. In particular, water and ethanol may be used.

In addition, the natural extract soluble in a nonpolar solvent, particularly dichloromethane-soluble extract, which is suitable for the present invention, can be obtained by suspending the natural extract obtained as above in distilled water and then subjecting the suspension to hot-water extraction or fractionation with a nonpolar solvent such as dichloromethane, n-hexane, chloroform, or ethyl acetate.

In addition, the natural extract according to the present invention can be prepared by other volatile oil extraction methods such as steam distillation, compression, adsorption, exudation, supercritical gas extraction, and the like.

The above natural plant extracts can be used alone or as a mixture of two or more. Basic solvents (substrate solvents) used to dissolve at least one of the above natural plant extracts and enhance compatibility and odor duration include dipropylene glycol, dioctyl adipate (DOA), isopropyl myristate (IPM), Propylene Glycol (PG), hydrogenated methyl abietate (floralyn), and the like.

The natural plant extract of the present invention shows an insecticidal effect against adults or larvae of various types of pests. Such pests include, but are not limited to, hygiene pests, storage article/food pests, agricultural pests, tree pests, and forest pests. Examples of sanitary pests include, but are not limited to, mosquitoes, flies, cockroaches, lice, and ants. Examples of storage product/food pests include, but are not limited to, shell powder black moths (Pludia interpunctella), pissodes, rice weevils, cardia borer (Cardiacaulla), Paralipia guilis, wheat moths (Sitotroga cerealella), Tribolium castaneum (Tribolium castaneum), tobacco beetles (Lasioderma serricorn), Oryza subulata (Oryzaephius surrinamensis), Phragmites (Phragmites britis Brennervoni Waltenwy), Black bark beetles (bark beetle), white bark beetles (Dermets bugles), and various carpet bark beetles (bark beetles). Examples of tree pests include, but are not limited to, termites (termites), and examples of forest pests include, but are not limited to, pine needle gall midges (theodiposis japonensis), fall webworm (hypanthria cunea), valentine moth (Malacosoma neustris), gipsymoth (Lymantria dispar), cicada (Lymantria dispar), scarab (mimosa), aphid, mites, black pine trunk beetle (matsumusthunbergiana), pachylon parviensis (achlygodaki), fir borer (dinoryptabilis), common pine bark beetles (tomicornia piniperda), and the like. Examples of agricultural pests include, but are not limited to, greenhouse whitefly (Trialeurodes vaporariorum), brown planthopper (Nilaparvata lugens Stal), brown planthopper (laodelphax striatus Fallen), Sogatella furcifera, rice leafhopper (rice greenleafhopper), electric leafhopper (zigzag-striped leafhopper), and the like.

The natural plant extracts prepared above are microencapsulated so that they exhibit a sustained pesticidal effect. The term "encapsulation" as used herein refers to the process of preparing particles comprising an active ingredient inside and outside the shell, wherein the active ingredient contained within the shell and the ingredients of the shell can be differentially determined depending on the purpose of microencapsulation. Encapsulation may be performed to allow, for example, 1) changing from a liquid to a solid state for ease of handling and storage, 2) isolating substances that react with each other, 3) adjusting the release rate of the active ingredient within the microcapsule, 4) masking unpleasant tastes or odors, or 5) protecting unstable substances.

The microcapsules containing a natural plant extract exhibiting an insecticidal effect prepared according to the present invention can exhibit a sustained insecticidal effect by regulating the release rate of the encapsulated natural plant extract within the microcapsules while protecting the safety of the natural plant extract with respect to the external environment.

The term "pesticidal microcapsule" as used herein refers to a microcapsule comprising a natural plant extract microencapsulated in a shell, which exhibits a pesticidal effect, thereby ensuring the controlled release and safety of the natural plant extract to continuously exhibit an excellent pesticidal effect.

The pesticidal microcapsules according to the present invention can be prepared by various methods known in the art. The encapsulation process for the lipophilic component generally includes interfacial polymerization, spray drying, in situ polymerization, and the like. In particular, methods for preparing microcapsules containing an aromatic component as a core material are disclosed in U.S. patent nos. 5,011,634, 4,965,025, and 4,824,823, and german patent No. 3,543,803 and the like.

According to the present invention, the pesticidal capsule comprising a natural plant extract may be prepared by: preparing a distillate by dissolving at least one natural plant extract in a hydrocarbon solution; stirring the distillate and the emulsifier at a speed of 100 to 12,000rpm to form a finely distributed emulsion; preparing a prepolymerization solution by using urea or melamine, formaldehyde, and water; the prepolymerisation solution is then polymerised at 50 to 90 ℃ by addition of a weakly acidic additive, wherein the temperature of the emulsion is between 10 to 50 ℃, and the prepolymerisation solution is cooled at a temperature of 30 to 60 ℃ prior to polymerisation.

The above-prepared pesticidal microcapsule contains 5 to 30% by weight of a natural plant extract. When the content of the natural plant extract in the microcapsule is too small to emit odor, a sufficient pesticidal effect cannot be expected. On the other hand, when the content of the natural plant extract is too high, the product emits too strong odor and is unpleasant to consumers, although it has excellent pesticidal effects.

The thickness of the urea-formaldehyde or melamine-formaldehyde layer of the microcapsules can be adjusted by varying the ratio of the emulsion to the pre-polymerization solution. When the resin layer is too thin, the durability may be poor; when the resin layer is too thick, the microcapsules are not broken, thereby inhibiting the pesticidal effect of the natural plant extract exhibited in the disposable absorbent article.

In disposable absorbent articles comprising a disposable absorbent article comprising a liquid-permeable topsheet, an absorbent core, and a liquid-impermeable backsheet (or backsheet), the pesticidal microcapsules prepared according to the present invention may be applied to the liquid-permeable topsheet, absorbent core, liquid-impermeable backsheet, flaps, rings, hooks, packaging materials, and the like, to exhibit their pesticidal effects. In particular, the pesticidal microcapsules can be applied to the lower sheet to effectively prevent the invasion of pests into the article. In particular, the pesticidal microcapsules according to the present invention can be incorporated into the disposable absorbent article at about 0.006 wt% to 0.03 wt%, based on the total weight of the disposable absorbent article. In one embodiment of the present invention, the pesticidal microcapsules according to the present invention can be applied to a backsheet in the form of a film or nonwoven to impart a pesticidal effect to the disposable absorbent article.

The backsheet (or backsheet) of the absorbent article of the present invention may be in the form of a film, a nonwoven, and a film/nonwoven laminate.

First, a lower sheet in the form of a film containing an insect-killing microcapsule is described. The backsheet in the form of a film according to the present invention may be prepared by molding or stretch film extrusion or other suitable film forming techniques after preparing a masterbatch by mixing the pesticidal microcapsules with the thermoplastic polymer forming the substrate of the backsheet. However, in order to maintain a sustained pesticidal effect, it is desirable to prepare the lower sheet by casting the masterbatch through a T die at about 170 ℃ to 240 ℃, particularly about 180 ℃ to 230 ℃.

The lower sheet in the above film form prepared by the T-slot according to the present invention can be prepared as follows:

first, the pesticidal microcapsules of the present invention are mixed with a thermoplastic polymer in a desired ratio to prepare a master batch. The masterbatch was added to an extruder and then melted and mixed. The fine dispersion was directed through a Screen Pack apparatus inside a T-die and impurities were removed. The master batch was then cast into a film by a T die and the cast film was passed through a chill roll. The film is then cut to the desired width and then coiled to produce a lower sheet of the film form of the invention. Corona treatment or embossing is a typical process for preparing the lower sheet and may be added to the above preparation process if desired.

The master batch containing the pesticidal microcapsules for preparing the film-form base sheet according to the present invention contains 40% to 50% of a thermoplastic polymer, 40% to 50% of a filler, 1% to 10% of the pesticidal microcapsules, and 0.1% to 5% of an additive. The additives of the master batch comprising the pesticidal microcapsules may vary depending on the desired properties, such as antioxidants, dyes, etc.

Suitable thermoplastic polymers for use in the concentrate containing the pesticidal microcapsules include, but are not limited to, VLDPE (very low density polyethylene), LDPE (low density polyethylene), HDPE (high density polyethylene), polypropylene, ethylene and ethylene with C₃-C₁₂Copolymers of alpha-olefins, propylene with ethylene and/or C₄-C₁₂Copolymers of alpha-olefins, soluble polyolefins comprising propylene-based polymers containing all atactic and isotactic propylene units in the polypropylene backbone, elastomers such as polyurethanes, copolyetheresters, and polyester degradable resins, polyamide polyether block copolymers, ethylene vinyl acetate copolymers, block copolymers of formula a-B-a' or a-B such as copoly (styrene/ethylene-butylene), styrene-poly (ethylene-butylene) -styrene, polystyrene/poly (ethylene-butylene)/polystyrene, poly (styrene/ethylene-butylene/styrene), and the like.

Suitable amounts of the inventive pesticidal microcapsules applied according to the above method are about 0.01 wt% to 0.5 wt%, especially about 0.01 wt% to 0.3 wt%, based on the total weight of the lower sheet. When the amount of the pesticidal microcapsule is less than 0.01 wt%, a desired pesticidal effect cannot be obtained. However, when the amount of the above-mentioned pesticidal microcapsules is more than 0.5% by weight, odor reaches a detectable level and is thus also undesirable.

In another embodiment, permeable films can also be made as a backsheet of the present invention by uniaxially or biaxially stretching the film in multiple steps, such as preheating, stretching and heat setting, wherein the film is prepared by casting a masterbatch containing the pesticidal microcapsules, the masterbatch additionally comprising filler particles such as CaCO₃And the stretching process thereof is performed twice, a suitable stretching temperature is set at about 20 to 70 ℃, particularly about 40 to 45 ℃, and a suitable stretching ratio is about 160 to 350%, particularly about 180 to 220%, in consideration of evaporation and decomposition of the microcapsule. The heat-fixing process is performed at 20 to 100 deg.c, especially about 70 deg.c or less, in consideration of evaporation and decomposition of the microcapsule.

The above stretched film has a thickness that makes the structure integral and liquid-impermeable. The film has a thickness under stretch of about 50 to 300 microns, especially about 100 microns.

In addition, the backsheet in the present invention may be prepared by spunbond, meltblown, thermal bond comb, spunlace nonwoven (spunlace), spunbond-meltblown-spunbond (SMS), or spunbond-meltblown-spunbond (SMMS), especially SMS or SMMS nonwovens prepared by conventional methods using a master batch containing the pesticidal microcapsules.

The nonwoven fabric containing the pesticidal microcapsules can be prepared, for example, by impregnating a yarn containing the pesticidal microcapsules obtained by mixing the pesticidal microcapsules with a master batch, or by a printing method.

In particular, the nonwoven obtained by using impregnation can be prepared by the following steps:

1) preparing a nonwoven fabric by a general method;

2) making the prepared non-woven fabric pass through a sedimentation tank in which the deinsectization microcapsule is added; and

3) the nonwoven fabric passed through the sedimentation tank was dried in hot air at a set temperature.

In one embodiment of the present invention, after preparing a general nonwoven fabric, the nonwoven fabric is treated with the pesticidal microcapsules by a post-treatment process, for example, unwinding the nonwoven fabric wound on an unwinding roll (unwinding roll), passing the nonwoven fabric through a settling tank containing the pesticidal microcapsules and performing adhesive mixing therein, and then after drying the nonwoven fabric at constant temperature by using hot air to adhere the pesticidal microcapsules to the nonwoven fabric, the nonwoven fabric is wound on a winding roll to obtain a nonwoven fabric coated with the pesticidal microcapsules.

The nonwoven fabric obtained by using the printing method may be prepared by the following steps:

1) preparing a nonwoven fabric by a general method; and

2) passing the obtained nonwoven fabric through a printing plate and a stamp having the pesticidal microcapsules of the present invention dispersed therein

Brushing the solution to adhere to the solution, wherein the pesticidal microcapsules are dispersed on the nonwoven fabric.

In another embodiment of the present invention, after the nonwoven fabric is conventionally prepared, the nonwoven film wound on the unwinding shaft is unwound and passed through a printing plate and a printing solution in which the pesticidal microcapsules are dispersed. The solution in which the pesticidal microcapsules are dispersed is adhered to the nonwoven fabric like printing, and thereby a nonwoven fabric having the pesticidal microcapsules adhered thereto in a desired shape at a desired position by printing is obtained.

The nonwoven obtained by using the masterbatch can be prepared by carrying out the following steps in a continuous manner:

1) preparing a master batch by mixing a thermoplastic polymer for preparing a non-woven fabric with the pesticidal microcapsule of the present invention in a specific ratio;

2) preparing a yarn containing the pesticidal microcapsules by passing the master batch through a fiber weaving machine; and

3) a non-woven fabric is prepared by passing the yarn through a non-woven molding device.

The nonwoven fabric specifically contains the pesticidal microcapsules of the present invention in an amount of 0.01 to 0.5 wt% based on the total weight of the thermoplastic polymer constituting the nonwoven fabric.

In another embodiment of the invention, the pesticidal microcapsules are incorporated into the yarns used to make the nonwoven fabric prior to making the nonwoven fabric to make a nonwoven fabric comprising the pesticidal microcapsules. The yarn is prepared by incorporating the pesticidal microcapsules into a masterbatch. That is, the masterbatch is prepared by mixing the thermoplastic polymer with the pesticidal microcapsules in a specific ratio; the thread yarn containing the deinsectization microcapsule is prepared by using a fiber weaving machine; the thread containing the pesticidal microcapsules is then placed in a non-woven molding device such that the non-woven fabric contains the pesticidal microcapsules.

The method for preparing a nonwoven fabric from a yarn prepared by incorporating pest control microcapsules into a master batch for preparing a nonwoven fabric can overcome the disadvantages that the pest control microcapsules on a disposable absorbent article are stuck to the skin of a user or washed off due to secretions after being detached from the nonwoven fabric.

In addition, the rear sheet according to the present invention may be prepared by laminating a film containing the pesticidal microcapsules with a general non-woven fabric using an adhesive, such as a solvent-type glue, a hot metal adhesive, or a cold glue, by heat-sealing or laminating the film containing the pesticidal microcapsules with the general film, or may be a film/non-woven fabric laminate in which the film containing the pesticidal microcapsules is laminated with the non-woven fabric containing the pesticidal microcapsules, wherein the amount of the applied pesticidal microcapsules is about 0.01 wt% to 0.5 wt% based on the total weight of the film/non-woven fabric laminate.

The liquid-impermeable lower sheet in the form of a film or nonwoven fabric comprising the pesticidal microcapsules containing at least one natural plant extract of the present invention prepared as described above may be applied to conventional disposable absorbent articles along with a liquid-permeable upper sheet and an absorbent core as are well known in the art.

Accordingly, included within the scope of the present invention is a disposable absorbent article comprising a liquid-permeable upper sheet which, in use, is in contact with the skin of the user, an absorbent core which is positioned below the upper sheet and which will absorb and disperse bodily fluids, and a liquid-impermeable lower sheet which is positioned below the absorbent core, wherein the liquid-impermeable lower sheet comprises pesticidal microcapsules comprising at least one natural plant extract.

Disposable absorbent articles containing the pesticidal microcapsules according to the present invention include, but are not limited to, baby diapers, adult diapers, sanitary napkins, toilet training pants, panty liners, and the like.

The topsheet used in the present invention may be prepared from a variety of materials, including porous foams, reticulated foams, apertured plastic films, non-woven fabrics, natural fibers, synthetic fibers, or a combination of natural and synthetic fibers. For example, the topsheet may be a spunbond web of polyolefin fibers, a spunlace nonwoven (spunlace nonwoven), or a spunbond carded web of natural and/or synthetic fibers. Thus, the topsheet may be treated with a hydrophobic material that has been treated with a surfactant or otherwise treated to achieve the desired levels of wettability and liquid permeability. Examples of upper sheets are disclosed in U.S. patent nos. 5,879,343, 5,490,846, and 5,364,382, and U.S. patent application No. 09/209,177, among others.

The adsorbent core useful in the present invention may comprise at least one adsorbent, such as superabsorbent particles, wood pulp fluff fibers, synthetic grass pulp fibers, synthetic fibers, or mixtures thereof. The adsorbent core may exist in a variety of forms and its size may vary depending on the target absorption capacity, the purpose of use of the adsorbent article, and other factors known to those skilled in the art.

Hereinafter, the present invention will be described more specifically with reference to the following examples. The following examples are provided only to more specifically illustrate the present invention, and those skilled in the art will recognize that the present invention is not limited to these examples.

Examples

Example 1: preparation of pesticidal microcapsules

To prepare the microcapsule containing cinnamon extract and rosemary extract, cinnamon extract (CAS No 8015-91-6, cinnamon oil, Trinity), rosemary extract (CAS No 8000-25-7, rosemary oil, Trinity), and a mixture thereof were dissolved in a hydrocarbon solvent and diluted with a hydrocarbon solvent. The diluted solution was then stirred with a cationic surfactant as an emulsifier at 2,000-3,000rpm for 5-10 minutes using a homomixer to prepare a micronized emulsion of a certain size. Melamine, formaldehyde, and water are mixed together in a certain ratio and adjusted to a neutral pH. The mixture was stirred at a suitable temperature to prepare a prepolymerization solution. To the pre-polymerization solution and the finely dispersed emulsion, 0.1 to 5% by weight, based on the weight of the emulsion, of acetic acid as a weakly acidic additive is added. The polymerization reaction is carried out while stirring the mixture at a suitable temperature for 100 to 300 minutes. After cooling to room temperature, aqueous ammonia was added to the mixture to remove residual formaldehyde, followed by stirring for at least one hour. Subsequently, there is obtained an insecticidal microcapsule comprising cinnamon extract, rosemary extract, and a mixture thereof, having a particle size of 1 to 10 μm.

Example 2: preparation of disposable absorbent articles comprising pest control microcapsules having a lower sheet in the form of a film

10% of the pesticidal microcapsules comprising cinnamon extract, rosemary extract, and a mixture thereof prepared in example 1, 40% of low density polyethylene, and 50% of a filler (calcium carbonate) were mixed together to prepare a master batch comprising the pesticidal microcapsules. The prepared masterbatch was cast through a T die at about 200 ℃ to make a film. The prepared film was uniaxially stretched at a stretching temperature of about 40 ℃ at a stretch ratio of about 200 to 300% to produce a breathable-type backsheet. A disposable diaper was produced by a conventional method using the film produced above as a backsheet.

Example 3: preparation of disposable absorbent articles having nonwoven lower sheet containing pesticidal microcapsules

The master batch containing the pesticidal microcapsules prepared in example 1, which contained cinnamon extract, rosemary extract, and a mixture thereof, 10% and polypropylene 90% were mixed together to prepare a master batch. The prepared master batch was mixed with polypropylene in a ratio of 1: 99. The mixture is spun through a fiber spinning machine to produce a yarn containing the pesticidal microcapsules. The nonwoven fabric was prepared using a yarn prepared by a nonwoven molding machine. A disposable diaper was produced by a conventional method using the nonwoven fabric prepared above as a backsheet.

Example 4: pesticidal effect of disposable absorbent articles comprising pesticidal microcapsules

In order to examine the pesticidal effect of the disposable diapers including the pesticidal microcapsules containing the cinnamon extract, the rosemary extract, and the mixture thereof prepared in the above examples 2 and 3, the following experiment was performed.

First, a disposable diaper comprising pesticidal microcapsules containing cinnamon extract (CIN), rosemary extract (R), or a mixture thereof (RC), and a control group without pesticidal microcapsules were put into four (4) high-density pest spaces (40 × 30 × 40cm) made of acrylic resin. 500 Indian rice moth larvae of 4 weeks old were placed in the space (FIG. 1). The temperature in the space of high density pest is maintained at 28 deg.C and the relative humidity is maintained between 70% and 75%. After the larvae were put into the space, the number of larvae attached to each diaper was checked every 24 hours for 30 days. Results were statistically calculated using analysis of variance (NOVA test).

TABLE 1

	CIN	R	RC	CON 20
					Inner part	0.292±0.550A	0.708±0.999AB		3.666±2.254C
Exterior part	3.458±1.865A	5.458±3.230B		4.292±2.216AB
					Total of	3.750±1.939A	6.167±3.130B	3.611±1.914A	7.958±3.277BC

As can be seen from table 1, the disposable diaper comprising the pesticidal microcapsule containing cinnamon extract, rosemary extract, or a mixture thereof according to the present invention showed a statistically significant lower number of attachments both on the inside and outside of the diaper, compared to the untreated control group. A, B, AB, C, and BC in the above table represent groups classified as statistically significant individuals: group a had fewer larvae entering the disposable absorbent article than group B, which had fewer larvae than group C, while group AB represented an intermediate value between groups a and B, and group BC represented an intermediate value between groups B and C.

The above data clearly show that the disposable absorbent article of the present invention comprising the pesticidal microcapsules comprising a plant extract which naturally exhibits a pesticidal effect and is harmless to the human body continuously exhibits an excellent pesticidal effect and thus can effectively prevent invasion of pests which may occur during distribution and storage of the product.

Although specific embodiments of the present invention have been described herein in considerable detail, those of ordinary skill in the art will recognize that such embodiments are merely exemplary and that the present invention is not limited to such embodiments. It is therefore intended that the substantial scope of the present invention be defined by the appended claims and equivalents thereof.

Claims (4)

1. A disposable absorbent article comprising a liquid-impregnable upper sheet, an absorbent core, and a liquid-impermeable lower sheet, characterized in that a natural plant extract exhibiting an insecticidal effect is microencapsulated and applied to the insecticidal microcapsules of the absorbent article, the insecticidal microcapsules being capable of being applied to a film prepared by casting a master batch containing a thermoplastic polymer forming a lower sheet matrix and the insecticidal microcapsules through a T-die at 170 ℃ to 240 ℃ and passing it through a cooling roll, or a lower sheet of a non-woven fabric prepared by a non-woven molding device after preparing a yarn containing the insecticidal microcapsules by a fiber textile machine using the master batch containing the thermoplastic polymer and the insecticidal microcapsules, wherein the insecticidal microcapsules contain 5 wt% to 30 wt% of the natural plant extract based on the total weight of the microcapsules, wherein the article comprises 0.0006 wt% to 0.03 wt% of the insecticidal microcapsules based on the total weight of the disposable absorbent article .

2. The disposable absorbent article of claim 1, wherein the natural plant is selected from the group consisting of cinnamon, rosemary, lavender, peppermint, eucalyptus, and mixtures thereof.

3. The disposable absorbent article of claim 1, wherein the lower sheet comprises from 0.01 wt% to 0.5 wt% of the pesticidal microcapsules based on the total weight of the lower sheet.

4. The disposable absorbent article of claim 1 or 2, wherein the disposable absorbent article is an infant diaper, an adult diaper, a sanitary napkin, a toilet training pant, and a panty liner.