CN1177575C - Absorbent article having improved comfort during use by improved fit even when loaded and improved rewet performance - Google Patents

Abstract

The present invention relates to a moisture absorption article which comprises a moisture absorption core with a crotch region and at least one lumbar region, wherein the final liquid storage capacity of the crotch region is lower than that of the lumbar region. The moisture absorption article also has the improved liquid processing performance and especially has a low leakage-back value to reduce the hydration of skin during use. The leakage-back value measured by an absorbed collagen leakage-back method does not exceed 180 milligrams.

Description

The absorbent device that still has improved stickiness and bleeding back property during receiving fluids

Technical field

The present invention relates to be mainly used in reception and hold the absorbent device of urinating the bodily exudate of a class such as (and mainly being).These articles for use are disposable hygienic article, as baby diaper, training pant, adult-incontinence articles, or the like.

Background technology

Being used to receive and holding the absorbent device such as the bodily exudate of urine and feces one class, as disposable diaper, training pant, adult-incontinence articles etc., has been known in the art, and people have spent a large amount of effort and improve their performance.It all is major function at these class articles for use usually that this class is improved, i.e. the function of receiving fluids, but comprise that also the comfort by improving the wearer farthest reduces by wearing the sense of discomfort that these class article cause.

This class is improved and mainly is divided into two big classes: a class relates generally to " core technology ", is " hygroscopicity " from broad sense; One class relates generally to " agent technology ".

The first kind is improved and is conceived to how bodily exudate (having certain fluidity usually) be obtained and is retained in one " hygroscopicity (or core) structure ", make described ejection to be received (obtaining) thus by described articles for use, store then (reservation), might between reception and storage step, also have a diffusing step (especially for urine).

Second class is improved and is related generally to so-called " body element ",, bodily exudate is held " in the sealed environment of articles for use " that is, and the mode of holding has:

--by adopting a kind of liquid-tight " egative film " absorbent portion (cored structure) and the external world (being underwear of wearer etc.) are separated;

--perhaps, prevent to leak out the space of bodily exudate between absorbent device and wearer's health for example by on leg opening and waist opening, adopting elastic component that closing in is gathered.

Also relate to and make the described articles for use can be by on one's body the wearer--for example by the packaged unit as frenulum one class is provided, and articles for use are remained on one's body the wearer, for example adopt usually and wear parts making all-in-one-piece strip-shaped parts.

Just the wearer is felt with regard to " comfortable " this theme, present main solution is to improve main element, for example makes articles for use can form good " docile " by the main element that improves diaper, and is softish.

In (Alemany's) PCT application WO 93/16669 or (Richardson's) PCT application WO93/21877, several disposable diapers have been described, by in these diapers, adopting the rubber-like parts, even for example when the wearer moves, also can make the mutually docile elastomeric element of diaper and health, strengthen wearer's comfort.

When considering core components to the influencing of comfortableness, common way is to adopt material softish, that do not hinder skin to make top flat, the thickness of the articles for use when perhaps reducing to be in drying regime as far as possible and/or volume preferably keep the flexibility of this class core components simultaneously.Recently, people have also done the structure that improves hygroscopicity structure and shape obtaining the trial of good stickiness.

Since so-called super slurper (the perhaps material of aquogel type) was widely used in the disposable absorbent article, a large amount of commercially available prod of the sale in country variant was as by The Procter ﹠amp; PAMPERS that Gamble company sells and the HUGGIES that is sold by Kimberly-Clark company have experienced significantly reducing of product thickness.

(Pieniak's) U.S. Pat-A-5098423 has described several disposable diapers; this part patent solves the problem of " comfortableness " from every side by the structure that " low dry bulk " is provided; its claimed scope not only relates to the thickness of structure when drying, also relates to other size, as

--the cross-sectional area that is in the part in the crotch district of absorbent article core;

--the compressibility that is in the part in the crotch district and the thickness of articles for use after folding of product

--the size of " plastic zones of articles for use "

--the distance between (shank) elastic component of articles for use.

Therefore, described cored structure is very thin, but broad.

And the amount of the liquid that this part patent also will be drawn the crotch district and the absorbent article core volume when drying connects, and has described one " moisture absorption efficiency index ".The purpose of this parameter is to make design can be conceived to the absorption characteristic in crotch district, capacity.Also having a free-revving engine is that a large amount of urine is absorbed in the crotch district, but after having absorbed a large amount of liquid, the reduction of comfortableness is inevitable.Along with further improvement to the performance of absorbent device, the liquid handling performance of the absorbent device of being produced is significantly improved, thereby total time of wearing obtained increase, the amount showed increased of the liquid that these class articles for use were held before being removed, the problems referred to above just become more outstanding.

(Bernardin's) U.S. Pat A4994037 has described several absorbent devices with " reverse capacity distribution ".In these articles for use, maximum memory capacity is set on the position away from the crotch district.But, the disclosed absorbent device scheme of this part patent both do not considered for the stickiness requirement that forms good fit between wearer's two lower limbs, do not consider yet such as realize that skin is dry and comfortable and suitably obtain the liquid in the requirement aspect the liquid handling.Although on the position away from the liquid inlet point, they do not relate to and how effectively liquid to be sent in these memory blocks these designs with Capacity design.

Summary of the invention

Therefore, an object of the present invention is to provide such absorbent device, described absorbent device still has the stickiness of having improved when having held liquid, have the better fluid handling property simultaneously, particularly has a good performance that bleeds back.

In order to realize purpose of the present invention, the invention provides a kind of like this absorbent device, it comprises an absorbent article core, absorbent article core comprises crotch district and lumbar region, the length in crotch district is half of length of whole absorbent article core, the final liquid storage capacity in crotch district is less than 49% of the final liquid storage capacity of whole absorbent article core, and the collagen after the absorption in the crotch district of absorbent device bleeds back the method measured value less than 180 milligrams.

Another object of the present invention is to realize its purpose by selectively maximum storage capacity being arranged on the position away from the crotch district.

Another purpose of the present invention is by designing the volume of articles for use in the crotch district smaller, makes articles for use have above-mentioned feature under the prerequisite that stickiness during in drying does not have a negative impact to articles for use.

Another purpose of the present invention is to achieve the above object by the diffusion material that employing has a wicking characteristic of high flow capacity.

Another purpose of the present invention is by adopting super absorbent polymer to achieve the above object.

Another purpose of the present invention is by adopting porous hygroscopic materials, as realizing above-mentioned purpose by the produced material of HIPE polyreaction.

Description of drawings

Fig. 1 is that example has schematically illustrated a kind of absorbent device with a kind of baby diaper.

Fig. 2 is that example has schematically illustrated a kind of absorbent device with a kind of baby diaper of pull-on type.

Fig. 3 represents to carry out the assay device of vertical wicking test.

Fig. 4 represents to carry out the assay device of acceptance test.

Collagen after Fig. 5 represents to be used to receive bleeds back the assay device of method.

The specific embodiment

Absorbent device--introduction

In this article, " absorbent device " vocabulary shows the articles for use that absorb and hold body excretions, or rather, expression be placed on the wearer's body or health near, be used for absorbing and hold the articles for use of the various Excretas (mainly being urine) of discharging from health.

" disposable " vocabulary shows does not plan this absorbent device is washed or otherwise recovers as absorbent device or reuse (promptly, they will be dropped after using once, preferably reclaimed, made fertilizer or with mode environmentally compatible they are carried out other disposal with a kind of).

An absorbent device generally includes:

--absorbent article core or cored structure (can comprise some substructures);

--the top flat that liquid can see through;

--a liquid-tight egative film;

--can randomly comprise parts such as closure member or elastic component one class.

Fig. 1 is the plane graph of an embodiment of a kind of absorbent device of the present invention, and this embodiment is a diaper.

Diaper 20 among Fig. 1 is in contraction state its flattening, non-(promptly, elastic component in flank is retained in the original position with its relaxed state, remaining elastic component all is drawn out of), in order more to clearly illustrate the structure of diaper 20, its several portions is cutd open, and, make diaper 20 with that opposing part of wearer, promptly outer surface 52 is towards the reader.As shown in Figure 1, diaper 20 has that a top flat that preferably can be seen through by a liquid 24, liquid-tight egative film 26 that engages with top flat 24 and absorbent article core 28 between top flat 24 and egative film 26 form holds assembly 22; The a pair of ear shape fin made from elastic component 30; The a pair of leg cuff made from elastic component 32; An elastic waist sheet 34; And a closed component of forming by dual fastening assembly, in the drawings it totally is expressed as 36.Dual fastening assembly 36 preferably includes a main fastening assembly 38 and a waist closed component 40.Main fastening assembly 38 preferably is made up of a pair of fastener 42 and a bonding jumper 44.Waist closed component 40 shown in Figure 1 preferably includes a pair of first fixation kit 46 and one second fixation kit 48.Diaper 20 preferably also has near the location sticking patch 50 that is arranged on each first fixation kit 46.

Diaper 20 among Fig. 1 has an outer surface 52 (facing the reader in Fig. 1), one with the opposing inner surface of outer surface 52 54, one first lumbar region 56, second lumbar region 58 and the periphery 60 that by several outer rims of diaper 20 surrounds relative with first lumbar region 56, in periphery 60, article two, longitudinal edge is represented with 62, and two bases are represented with 64.The inner surface 54 of diaper 20 constitutes the part of in use pressing close to wearer's body (that is, inner surface 54 normally is made up of at least a portion of top flat 24 and other parts that engage with top flat 24) of diaper 20.Outer surface 52 constitute diapers 20 in use back to the part (that is, outer surface 52 normally is made up of at least a portion of egative film 26 and other parts that engage with egative film 26) of wearer's body.First lumbar region 56 and second lumbar region 58 extend to the transversal centerline 66 of diaper 20 respectively from two bases 64 of periphery 60.Two lumbar regions comprise the lateral plate of the Outboard Sections in district 68 and a pair of common formation lumbar region in separately.Represent to be arranged in two lateral plates of first lumbar region 56 with labelling 70, represent to be arranged in two lateral plates of second lumbar region 58 with labelling 72.Although described every pair of lateral plate or each lateral plate are not necessarily identical, they are mirror-symmetrical each other preferably.The lateral plate 72 that is arranged in second lumbar region 58 can flexibly stretch in the horizontal (that is the ear shape fin made from elastic component 30).(laterally (directions X or width) is defined as being parallel to the direction of the transversal centerline 66 of diaper 20; Vertically (Y direction or length direction) is defined as being parallel to the direction of longitudinal midline 67; Axially (Z direction or thickness direction) is defined as running through the direction of the thickness of diaper 20.)

Fig. 1 illustrates a specific embodiment of diaper 20, and in this embodiment, the length and width size of top flat 24 and egative film 26 is all greater than the length and width size of absorbent article core 28.Top flat 24 and egative film 26 are stretched over outside the edge of absorbent article core 28, and form the periphery 60 of diaper 20 thus.Periphery 60 surrounds the outward flange of diaper 20, perhaps, in other words, constitutes each bar edge of diaper 20.Periphery 60 comprises longitudinal edge 62 and base 64.

As shown in Figure 1, the major part (main body) of holding assembly 22 formation diapers 20 of diaper 20.Hold assembly 22 and comprise at least one absorbent article core 28, and the outer cover of preferably forming by top flat 24 and egative film 26.When absorbent device comprises independently sheath and lining, hold assembly 22 and generally include this sheath and lining (promptly, hold assembly 22 and comprise that one or more layers constitutes the material of this sheath, lining then is made up of hygroscopic complex, for example by a top flat, an egative film and an absorbent article core are formed).For one-piece type absorbent device, hold the primary structure that assembly 22 constitutes diaper, add other parts, form the diaper structure of combined type.Therefore, the assembly 22 that holds of diaper 20 generally includes top flat 24, egative film 26, and absorbent article core 28.

Although the leg cuff made from elastic component 32 can be made structurally with lower limb hoop, flank, barrier cuff or elasticity recited above close up similar, preferably as above the U.S. Pat quoted as proof 4909803 leg cuff 32 that each made described with elastic component comprise one at least by a slice shaping piece 85 and the interior barrier cuff that elastic distance member 86 is formed.In a preferred embodiment, the leg cuff made from elastic component 32 also have one as above the U.S. Pat 4695278 described the sort of elastic sealings of quoting as proof close up 104, this sealing is closed up and is had one or more elastic cord 105 that is in barrier cuff 84 outsides.

Diaper 20 can also have an elastic waist plate 34 that is used to improve applying and sealing property.Elastic waist plate 34 is that at least one beginning from two waist edge 83 of absorbent article core 28 longitudinally stretches out in middle district 68 at least, and integrally constitutes at least a portion on the base 64 of diaper 20.Therefore, elastic waist plate 34 is on the diaper to be that part that the waist edge 83 from absorbent article core 28 extends to the base 64 of diaper 20 and will paste wearer's waist when wearing at least.Disposable diaper has two elastic waist plates usually, and one is positioned at first lumbar region, and one is positioned at second lumbar region.Although disposable diaper of the present invention both can have an elastic waist plate around the wearer, also can have a reinforcing waist sheet that only has the back elastic component, but the discussion of relevant elastic waist plate will be carried out at the diaper with a pair of elastic waist plate, and this is to having at least one, best two all to constitute according to the present invention in the waist sheet.In addition, although elastic waist plate or its any one element can be the independent components on the assembly 22 of holding attached to diaper 20, but in a preferred embodiment, to be described as elastic waist plate 34 by other element of diaper 20 for example egative film 26 or top flat 24, preferably the two extension of egative film 26 and top flat 24 constitutes.

The waistband made from elastic component 35 on the elastic waist plate 34 can comprise that on the part, egative film 26 of top flat 24 has preferably passed through the part of mechanical stretching and one and comprised that one is clipped in elastomer member 76 between top flat 24 and the egative film 26 and one and is clipped in egative film 26 and the double layer material that elastic parts 77 are arranged between the elastic parts 76 is arranged.

In WO93/16669, describe these parts and other parts in more detail, introduced this part patent herein as a reference.

Fig. 2 illustrates another embodiment that can use absorbent device of the present invention, promptly a kind of disposable diaper.This disposable diaper 20 comprises main body, latasuture 10 and hygroscopic assembly 22.Main body has anterior 56 at least, rear portion 58, crotch portion 57, vertical lateral areas and ear shape fin 30, and rubber-like ear shape tab member 90, described ear shape tab member 90 is operatively connecting each ear shape fin 30, forms the ear shape fin 30 of a laminated, the ear shape fin of this laminated has just had elasticity after having passed through the mechanical stretching processing, the back will make a more detailed description this stretch processing.Hygroscopic assembly 22 is fixed on the main body.

Outer 26 is those parts of the outside of the formation disposable diaper 20 on the main body, i.e. that part of wearer dorsad.Outer 26 is submissive, soft, and to the wearer's skin nonirritant.

Internal layer 24 is those parts of the inside of the formation main body on the main body, and this part contacts with shank with wearer's waist at least.Internal layer also is submissive, soft, and to the wearer's skin nonirritant.

Preferably internal layer 24 is being pasted outer 26 and placing, and utilizing fixing means (not shown) for example as known in the art that internal layer 24 is bonded on outer 26.For example, can internal layer 26 be fixed on outer 26 with an even successive adhesive coating, a patterned adhesive coating or the adhesive coating of forming by a series of independently lines, helix or point.

According to one embodiment of present invention, in the mode that internal layer 24 and outer 26 directly is bonded on elastic ear shape tab member 90, elastic waist head member 76 and the elastic cord 105 internal layer 24 and outer 26 is bonded together indirectly, then they is joined directly in the part that reaches outside elastic ear shape tab member 90, elastic waist head member 76 and the elastic cord 105.

In a preferred embodiment, the internal layer 24 of main body and at least a portion of outer 26 will be subjected to mechanical stretching, to form the stretch laminate of " zero strain ", be made of the ear shape fin made from elastic component 30 this lamination.Therefore, internal layer 24 and skin 26 are preferably tensile, but pulling the most preferably, but needn't have elasticity, therefore, in case be subjected to mechanical stretching, internal layer 24 and outer 26 produces permanent elongation to a certain degree to I haven't seen you for ages, thereby the shape can not return to their initial distortion fully the time.In some preferred embodiments, internal layer 24 and outer 26 can stand mechanical stretching under the situation that over-drastic fracture do not occur or tear.Therefore, more preferably, internal layer 24 and outer 26 has lower yield strength on the direction perpendicular to machine trend (laterally).

The main body of disposable diaper 20 preferably also has a pair of leg cuff made from elastic component 32, and its effect is fluid partitioning and other body excretions better.Each leg cuff 32 made from elastic component can have the embodiment of several different minimizing body excretions in the leakage of shank.Although each leg cuff made from elastic component 32 can be made structurally similarly with lower limb hoop, flank, barrier cuff or elasticity recited above closing in, each leg cuff 32 made from elastic component preferably comprises sealing closing in 104 and one or more elastic cord 105 at least.

The main body of disposable diaper 20 preferably also has one, and what be arranged on disposable diaper 20 is near the base in the rear portion 58 the waistband made from elastic component 34 at least, more preferably has to be arranged in anterior 56 and the waistband made from elastic component 34 of rear portion 58 these two parts.The waistband of disposable diaper 20 is those parts of pasting wearer's waist in use.The waistband made from elastic component 34 is the parts that can keep certain area of coverage, contact and can flexibly stretch at least in the horizontal with wearer's waist, therefore can dynamically be fitted on wearer's the waist, and the waist that dynamically is suitable for the wearer, thereby can improve stickiness.Therefore, waistband that part that extends to the waist edge of absorbent article core from its base at least on the disposable diaper 20 normally.Although the waistband made from elastic component 34 can constitute attached to the individual components on the main body of disposable diaper 20 by one, but waistband is the extension of other parts on the disposable diaper 20 preferably, for example is internal layer 24, outer 25 or any built-up section of these parts and the extension that engages elastomeric material thereon.Perhaps, can make outside the top flat of absorbent assemblies 22 and the edge that egative film extends to absorbent article core, and have elastic material to engage thereon with one, form a waistband made from elastic component.Disposable training pant has two waistbands made from elastic component usually; One is arranged in anterior 56, one and is arranged in rear portion 58.It is the waistband made from elastic component 34 that is arranged in the mesozone at rear portion 58 at least that disposable diaper 20 has one at least.More forwardly the waistband that another one is made with elastic component is set in 56.Preferably these two waistbands made from elastic component 34 all are arranged between two ear shape fins made from elastic component 30.

The waistband made from elastic component 34 can be made multiple different shape.According to Fig. 2, the waistband made from elastic component 34 comprises elastic waistband parts 76 that are clipped between internal layer 24 and outer 26, and waistband 34 operatively combines with the front portion 56 and the rear portion 58 of one of internal layer 24 and outer 26 or the two and disposable diaper 20.

In a preferred embodiment, main body forwardly 56 and rear portion 58 in all have the ear shape fin made from elastic component 30.The ear shape fin made from elastic component 30 is the parts that become one with main body, that is, they are not the independently manual parts that is fixed on the main body, but is formed by material of main part, is the extension of material of main part.The ear shape fin made from elastic component 30 has constituted the parts that can flexibly stretch, it is by fitting to this disposable pants suitably on wearer's the body earlier, then realizing more comfortable and docile applying, because the ear shape fin made from elastic component can stretch the lateral parts of disposable pants from beginning until maintain this applying in the whole process after having held Excreta the disposable pants.

Each ear shape fin 30 is made of that part that the mesozone from main body on the main body begins to extend to towards horizontal outside along this mesozone vertical side zones of main body.Ear shape fin 30 extends to main body generally along the longitudinal from the base of main body those of longitudinal edge form on the part (this section of longitudinal edge is known as the lower limb limit) of leg openings.In a preferred embodiment of the invention, each leg panel is made of the part outside the mesozone that extends to main body of internal layer 24 and outer 26.

In one embodiment of the invention, elastic ear shape tab member 90 operatively is combined on the main body in ear shape fin 30, preferably be combined between internal layer 24 and outer 26, therefore, this elastic ear shape tab member 90 makes the ear shape fin of being made by elastic component 30 be able to flexibly extend in the horizontal (transverse elasticity elongation)." flexibly elongation " speech herein refers to fragment of main body or part and can extend on a direction (preferably horizontal for ear shape fin and waistband) at least being subjected to pulling force (for ear shape fin and waistband lateral pull normally) time, and can return to its original size and dimension when pulling force is removed.In general, when stretching when unclamping immediately then to being used for the elastic material of having of the present invention, they can be retracted to about at least 75% (i.e. " instantaneous " elasticity) of their original-shapes in about 5 seconds or shorter time.

Absorbent article core/cored structure

Absorbent article core 28 should be submissive, docile and non-irritating to wearer's skin usually, and can absorb and keep the liquid such as urine and some other body excretions one class.As shown in Figure 1, absorbent article core 28 has a surface towards underwear (" bottom " or " bottom "), the surface towards health, two sides and two waist limits.Can have multiple Liquid Absorption or the liquid treatment material that is generally used in disposable diaper and other absorbent device in the absorbent article core, for example, but be not limited to, be referred to as the wood fragments slurry of gas felt; Has the meltblown polymer that becomes altogether; With chemical method sclerosis, modification or cross-linked cellulosic; Fabric with fabric sleeve and fabric laminate.

The name that JIUYUE in 1986 was authorized people such as Weisman on the 9th is called No. 4610678 patent of the U.S. of " highdensity absorbent structure "; The name of authorizing people such as Weisman on June 16th, 1987 is called No. 4673402 United States Patent (USP) of the U.S. of " absorbent device with double-deck absorbent article core "; The name that December in 1989 was authorized Angstadt on the 19th is called No. 4888231 United States Patent (USP) of the U.S. of " absorbent article core with a shop bisque "; European patent EP-A-0640330 of people such as Bewick-Sonntag; (people's such as Berg) U.S. Pat 5180622; (people's such as Roe) U.S. Pat 5102597; (LaVon) U.S. Pat 5387207 has all been described the example of some hygroscopicity structures.It is following to being used for the structure institute requirement of absorbent article core 28 to adopt this class formation to adapt to.

Absorbent article core 28 both can be a kind of cored structure of monolithic devices, also can be the combination of several absorbent article core structures, and these several absorbent article core structures can comprise one or more substructure again.Each described structure or substructure can have a kind of basic two-dimensional (promptly being a layer) or a kind of 3D shape.

The material that is used for absorbent article core

Absorbent article core of the present invention can be made by the fibrous material that forms fleece or fibre substrate.

The fiber that is used for the present invention comprises the fiber of those natural generations (modification or unmodified), and staple fibre.The natural fiber of suitable unmodified/modification comprises wood pulp, Corchorus olitorius L., artificial silk, ethyl cellulose and the cellulose acetate of cotton, Rhizoma Imperatae, bagasse, bristle, Caulis et Folium Lini, silk, Pilus Caprae seu Ovis, wood pulp, chemical modification.Suitable synthetic fibers can be by following material manufacture: polrvinyl chloride, polyvinyl fluoride, politef, polyvinylidene chloride, polyacrylate (for example ORLON ), polyvinyl acetate, polyvinyl acetate, polyvinyl alcohol insolubility or solubility, the polyolefin of polyethylene (for example PULPEX ) and polypropylene one class, the polyester of the polyamide of nylon one class, DACRON  or KODEL  one class, polyurethanes, polystyrene type or the like.The fiber that is adopted can be simple natural fiber, and simple synthetic fibers can also be any compatible compositions of natural fiber and synthetic fibers.The fiber that is used for the present invention can be hydrophilic fiber, can also be the combination of hydrophilic fibre and hydrophobic fibre.

With regard to many absorbent article cores according to the present invention or cored structure, it is more desirable adopting hydrophilic fiber.The suitable hydrophilic fibre that is used for the present invention comprises polyester fiber, hydrophilic nylon (HYDROFIL ) of the cellulose fibre of cellulose fibre, modification, artificial silk, polyethylene terephthalate (for example DACRON ) class etc.Suitable hydrophilic fibre also can be from obtaining through the hydrophobic fibre of hydrophilicity-imparting treatment, this fibrid has, the thermoplastic fibre of making by following material of handling through surface treatment or silicon for example: the polyolefin of polyethylene and polypropylene one class, polyacrylate, polyamide, polystyrene type, polyurethanes or the like.

Can make suitable wood pulp fibers by the known chemical method of kraft process and sulphite process one class.Especially preferably make these wood pulp celluloses, because these corks have remarkable moisture-absorption characteristics with southern cork.Can also make these wood pulp celluloses by the method for machinery, for example make by ground wood pulp method, correct grinding method, thermomechanical method, chemical mechanical pulping and chemistry-thermomechanical method wood pulp technology.Can adopt wood pulp cellulose and bleaching or unbleached wood pulp cellulose recovery or that secondary uses.

Be used for the present invention, especially for not only needing the better fluid receptivity but also needing a cellulose fibre that ideal source is a chemicosolidifying of the hydrophilic fibre in the moisture absorption zone of better fluid diffusion.In this article, the cellulose fibre that " cellulose fibre of chemicosolidifying " expression has been hardened by chemical means, described chemical means increased fiber do, hardness under the wet two states.These class means can comprise adds a kind of chemical hardening agent that for example applies and/or flood these fibers.These class means also can comprise by changing chemical constitution, for example make that polymer chain is crosslinked to come sclerotic fiber.

Can be used for applying or the polymerization sclerosing agent of impregnation of fibers cellulose fiber comprises: have the cationic modified starch of nitrogen-containing group (for example amino), for example can be from National and ChemicalCorp., Bridgewater, the product that NJ, USA buy; Latex; Wet-strength resins, for example polyamide-epichlorohydrin resins (for example can be, the Kymene  557H that Inc.Wilmington, Delaware buy) from Hercules; The polyacrylamide resin that No. 3556932 patent of the U.S. such as (Coscia people) of announcing on January 19th, 1971 described; By American Cyanamid Co., Stamford, CT, the polyacrylamide that USA sells with the trade name of Parez  631 NC; Urea-formaldehyde resin and melamine resin, and polyvinyl lactam resin.Can find one piece of relevant general paper that is used for the wet-strength resins of paper industry that can be applied among the present invention in (New York, nineteen sixty-five) from No. 29 TAPPI monograph separate edition of paper pulp and paper industry association " (wet strength paper and the cardboard ".

Can also make these fibrosclerosiss by chemical reaction.For example, cross-linking agent can be applied on the fiber, apply after the cross-linking agent, cause that these fibers form interfibrous cross-bond with chemical mode.These cross-bonds can increase the hardness of fiber.Although utilizing interfibrous cross-bond to make fibre chemistry sclerosis is a kind of preferred means, this and do not mean that get rid of other type be used to make the hardened reaction of fibre chemistry.

Following United States Patent (USP) has been described the hardened fiber of the cross-bond that has nothing in common with each other with form (that is sclerotic fiber that, has nothing in common with each other and their preparation method): No. 3224926 patent of the U.S. of (Bernardin) of the announcement on the 21st of nineteen sixty-five December; No. 3440135 patent of the U.S. of (Chung) that on April 22nd, 1969 announced; No. 3932209 patent of the U.S. of (Chatterjee) that on January 13rd, 1976 announced; No. 4035147 patent of the U.S. of people such as () Sangenis that December in 1989 was announced on the 19th; The U.S. 4898642d patent of people such as () Moore that announces February 6 nineteen ninety; No. 5137537 patent of the U.S. of people such as () Herron that announced on August 11st, 1992.

In present preferred sclerotic fiber, chemical treatment comprises to be carried out between fiber crosslinkedly with cross-linking agent, and these fibers are in twisting, the rolled state of a kind of relative dehydration, defiber (being unification) simultaneously.The normally monomeric cross-linking agent of suitable chemical hardening agent is particularly including the C2-C9 polycarboxylic acids of citric acid one class.

Can come quantitative expression twisting and this curling class sclerotic fiber with " twisting count " of fiber and " factor curls " of fiber." twisting count " speech used herein refers to the number of the sth. made by twisting tuberosity point on the certain-length that is present in fiber.Twisting count is used as a kind of mode of fiber around the degree of its longitudinal axis rotation of weighing.A speech refers to fiber and is roughly 180 ° around the rotation of the longitudinal axis " to twist with the fingers the tuberosity point ", and when when having adopted the microscopically observation fiber of transillumination for one, the part of fiber (promptly being somebody's turn to do " node ") presents the dark space with respect to the other parts of fiber.Because foregoing rotation, transillumination will pass through some extra fibre walls on some position, twists with the fingers tuberosity point and just is shown as the dark space at these positions.Distance between the node is corresponding to 180 ° axial rotation.The number of the sth. made by twisting tuberosity point on a certain length of fiber (being twisting count) is directly represented the degree of fiber twisting, is a physical parameter of fiber.U.S. Pat 4898642 has been described the method that is used for determining to twist with the fingers tuberosity point and total twisting count.

The average dried fibres twisting count of this class sclerotic fiber is at least about 2.7 every millimeter and twists with the fingers the tuberosity point, preferably is at least 4.5 every millimeter and twists with the fingers the tuberosity point.In addition, the average moistening fiber twisting count of these fibers preferably should be at least about 1.8 every millimeter and twist with the fingers the tuberosity points, more preferably be at least about 3.0 every millimeter and twist with the fingers the tuberosity points, and preferably every millimeter lack 0.5 sth. made by twisting tuberosity point than average dried fibres twisting count.More preferably, average dried fibres twisting count should be at least every millimeter about 5.5 and twist with the fingers the tuberosity point, and average moistening fiber twisting count should be at least every millimeter about 4.0 and twist with the fingers the tuberosity point, and every millimeter also should be lacked 1.0 sth. made by twisting tuberosity points than its average dried fibres twisting count at least.Most preferably, average dried fibres twisting count should be at least every millimeter about 6.5 and twist with the fingers the tuberosity point, and average moistening fiber twisting count should be at least every millimeter about 5.0 and twist with the fingers the tuberosity point, and every millimeter also should be lacked 1.0 sth. made by twisting tuberosity points than its average dried fibres twisting count at least.

Except twisting, these preferred sclerotic fibers also are curled.Fiber crimp can be described as the fiber that is caused by the knot in the fiber, twisting and/or bending and shorten relatively.For the purposes of the present invention, the curling of fiber measured on a two dimensional surface.Can come the degree of quantificational expression fiber crimp with the fiber crimp factor.Can determine the fiber crimp factor by on a two dimensional surface, observing fiber, i.e. two-dimensional measurement value of Juan Quing.In order to determine the factor that curls, need to measure the projected length L of fiber _RThe physical length L of (i.e. longest dimension that holds the two-dimensional rectangle of fiber) and fiber _ACan from following equation, calculate the fiber crimp factor then:

Factor=(L curls _A/ L _R)-1.

In U.S. Pat 4898642, described and to be used for measuring L _RAnd L _AImage analysis method.The curling factor of sclerotic fiber preferably is at least about 0.30, and the factor that more preferably curls is at least about 0.50.

With respect to unhardened cellulose fibre, some performance that cellulose fibre had of these chemicosolidifyings makes it to be specially adapted in some absorbent structure of the present invention.Except possess hydrophilic property, these sclerotic fibers also have unique hardness and elastic overall characteristic.

In some hygroscopicity structures, for example with any in the hygroscopicity structure that the thermoplastic polymer that can not melt under the temperature of damaged fiber is on a large scale made, can comprise any in these two kinds of fibers of synthetic fibers or thermoplastic fibre or this two kinds of fibers.The fusing point of this thermoplastic is preferably lower than about 190 ℃, is preferably between about 75 ℃ and about 175 ℃.Under any circumstance, the fusing point of this thermoplastic should not be lower than the storage temperature of absorbent structure when being used for absorbent device of this heat bonding.The fusing point of this thermoplastic is not less than about 50 ℃ usually.

Can make described thermoplastic with multiple thermoplastic polymer, thermoplastic fibre particularly, these thermoplastic polymers comprise: the polyolefin of polyethylene (for example PULPEX ) and polypropylene one class, polyester, copolyesters, polyvinyl acetate, polyamide, copolyamide, polystyrene, polyurethane, and as the copolymer of any material in front of vinyl chloride/vinylacetate one class.Suitable thermoplastic comprises the hydrophobic fibre through hydrophilicity-imparting treatment, this fibrid has, for example the thermoplastic fibre of being made by following material through surface treatment or silicon processing: the polyolefin of polyethylene and polypropylene one class, polypropylene, polyamide, polystyrene type, polyurethanes or the like.Make the surface of hydrophobicity thermoplastic fibre obtain hydrophilic method to be, surfactant with non-ionic or anionic surfactant one class is handled, for example spray this fiber, this fiber is immersed in a kind of surfactant or with this surfactant fuses in the process of producing this thermoplastic fibre as the part of polymer with a kind of surfactant.In fusion and after solidifying again, this surfactant can be retained in the surface of this thermoplastic fibre.Suitable surfactant comprises for example by ICIAmericas, Inc.of Wilmington, the Brij  76 that Delaware produces, and by GlycoChemical, Inc.of Greenwich, the various surfactants that Connecticut. sells with the trade mark of Pegosperser .Except non-ionic surfactant, can also adopt anionic surfactant.Can with about 0.2 consumption surfactant be applied in the thermoplastic fibre with for example about every square centimeter of thermoplastic fibre to about 1 gram surfactant.

Suitable thermoplastic fibre can be made (homofil) by a kind of polymer, also can be by make (for example bicomponent fibre) more than a kind of polymer.For example, the such thermoplastic fibre of " bicomponent fibre " expression, it comprises a core fibre of being made by a kind of polymer, this core fibre is wrapped in the thermoplasticity crust of being made by another kind of polymer.The fusion temperature of the polymer of formation crust is different with the fusion temperature of the polymer that constitutes core, is usually less than the fusion temperature of the polymer that constitutes core.Therefore, this bicomponent fibre is owing to the fusing of sheath polymer forms heat bonding, simultaneously the ideal strength characteristic that had of holding core polymer.

Be used for suitable bicomponent fibre of the present invention and can comprise crust/core pattern fiber: polyethylene/polypropylene, poly-ethyl acetate/polypropylene, polyethylene/polyester, polypropylene/polyester, copolyesters/polyester etc. with following combination of polymers.(for example be particularly suitable for herein bi-component thermoplastic fibre and be those cores and a bicomponent fibre with more low-melting copolyesters, poly-ethyl acetate or polyethylene sheath with a polypropylene or polyester, DANAKLON , CELBOND  or CHISSO  bicomponent fibre).These bicomponent fibres can be concentric, also can be eccentric.In this article, term " concentric " and " eccentric " expression is that this crust has homogeneous thickness or has thickness heterogeneous on the entire cross section of bicomponent fibre.In the time need providing higher compressive strength with less fiber thickness, eccentric bicomponent fibre is more satisfactory.The bicomponent fibre that is suitable for herein both can be non-crimping (being non-bending), also can be curling (promptly crooked).Can be by general weaving means, for example bicomponent fibre is curled, to realize the curling of a kind of outstanding two dimension or " put down " by stuffer box process or gear crimping method.

When adopting thermoplastic fibre, can adopt different length according to the difference of the concrete heat fusion joint of these fibers and desired other performance different.Generally speaking, the length of these thermoplastic fibres is about 0.3 to about 7.5 centimetres, is preferably about 0.4 to about 3.0 centimetres.Also the performance that can regulate these thermoplastic fibres by the diameter (measurement thickness) that changes these fibers comprises heat fusion joint.The diameter of these thermoplastic fibres generally uses denier's (per 9000 Micks are heavy) or dtex (decitex) (every ten thousand metres grammes per square metre) to define.The dtex of the bi-component thermoplastic fibre that is fit to can be a value far below 1 dtex (for example 0.4 dtex) between about 20 dtexs.

When producing absorbent device, can use described fibrous material with a kind of form of uniqueness, on production line, form air-flow method fibre structure.Described fiber also can be used as a kind of preform fleece or preform fabric.Then with these structures to be essentially endless or, again they to be cut into suitable dimensions for very long form (for example on roller, the bobbin) is transported on the production line of absorbent device.Can be before these materials and other material be combined into absorbent article core, or at the cutting absorbent article core and make described material and separately it is implemented above-mentioned technology during the absorbent article core co-extension.

The method of making this net or fabric has a lot, and these technologies are known in the art.

In principle, restricted hardly although be used to make the fiber of this net--the shaping of some specific mesh thing and technique for sticking may with some material or the incomplete compatibility of fiber type.

When single fiber being regarded as when being used for making the original material of net, if they can be listed in a kind of fluid media (medium)--fluid media (medium) is gas (air), and then this structure is generally known as " dry-laying "; If fluid media (medium) is a liquid, then this structure is generally known as " wet-laying "." wet-laying " is widely used in producing the napkin with very wide performance range.But this speech is most commonly used in the cellulosic material, also can comprise synthetic fibers.

" dry-laying " is widely used in the nonwoven web, and also often adopts carding process to form this net.Well-known " air lay method fabric " also belongs to this category.

Hot-melt polymer can squeeze and be sprayed into fiber, directly forms net (promptly saved the single fiber of first making, again at a processing step that independently forms net in the processing step) then.Final structure is collectively referred to as the non-woven fabric of melt-blown, perhaps, has been subjected to stretching greatly as fruit fiber, then is referred to as the spunbonded type fleece.

In addition, also can be with the incorporated formation net of one or more other forming techniques.

In order to make network structure have specific intensity and overall performance, generally to carry out bonding to them.The technology of extensive employing is (a) chemical adhesive or the heat bonding that (b) undertaken by the part fusing that makes net.For the latter, can compress fiber, form adhesive spots clearly, for for example non-woven material, these bonding points can cover a big chunk in the gross area, and it is 20% rarely seen that coverage value reaches.Perhaps, particularly for hope has low-density structure, can adopt " air-flow method " bonding, make a part of polymer (for example outer membrane material of BiCo fiber) melt by making thermal current pass net (being generally air lay method fleece).

After net forms and be bonding, can also be further processed to improve its specific performance properties them.This processing can be---as the example in many possible examples---to be added surfactant, hydrophobic fibre is become have more hydrophilic, or vice versa.Perhaps, as European patent application EP 96108427.4 is disclosed, can adopt the mechanical treatment after the shaping to make this class material have useful especially characteristic.

Select for use the fleece or the replacement fleece except adopting, can also comprise other porous material in the absorbent article core, as foam.Preferred foam is to carry out the open cell type hygroscopicity polymeric foam that polymerization is prepared by the water-in-oil emulsion (back is referred to as " HIPE ") to high inner phase.Can provide needed storage characteristics by forming this class polymeric foam, and needed diffusion property.

No. 08/563866 patent application of the U.S. (back is referred to as " the ' No. 866 patent applications ") of the common pending trial of being submitted November 25 nineteen ninety-five by people such as DesMarais described can be for the hipe foam that not only has needed diffusion property but also have needed storage characteristics of utilization of the present invention, and the content with this patent is incorporated herein by reference herein; Following patent also discloses this class A foam A: No. 08/542497 patent application of the U.S. of the common pending trial of people such as () Dyer that submits October 13 nineteen ninety-five; No. 5387207 United States Patent (USP) of people such as () Dyer that authorizes February 7 nineteen ninety-five; And on November 9th, 1993 No. 5260345 United States Patent (USP) such as (DesMarais people) of authorizing; Content with these patents is incorporated herein by reference herein.

The polymeric foam that can be used among the present invention is those foams of open cell type comparatively speaking.That is, this foamy each hole all with the hole that links to each other with it fully, unobstructedly communicate.This class basically opening or " fenestella " between the hole that hole had in the foaming structure of open cell type have enough big size, make the liquid in the foaming structure be able to import into other the hole from a hole easily.

These foaming structures that are essentially open cell type have a kind of netted characteristic usually, and wherein each hole all is that the three-dimensional branched network by some interconnection defines.Several strands of polymeric materials that constitute these branched network are known as " pillar ".In the Fig. 1 of the ' No. 866 applications and the shown microphotograph of Fig. 2, shown the foamy example of the open cell type with a kind of typical column support type structure.In this article, if the size in foaming structure has the hole hole adjacent with at least one more than 80% can carry out fluid exchange, claim that then this foamed materials is " open cell type " in the hole more than 1 micron.

Except open cell type, these polymeric foams also have enough hydrophilic, make foam can absorb aqueous liquid with the absorbtivity of stipulating later.By remaining in the remaining hydrophiling surfactant in the foaming structure after the polymerization,, make the inner surface possess hydrophilic property of these foaming structures perhaps by the foam treatment process after the selective polymerization.

Described polymeric foam can be prepared into (promptly unexpanded) polymeric foam that contracts flat, in a single day these foams contact with aqueous liquid, just can expand, and absorb these liquid.For example, can be referring to No. 08/563866 U.S. Patent application and No. 5387207 United States Patent (USP) of common pending trial.The method that obtains these flat polymeric foams that contract is normally: by exerting pressure, and/or heating, drying and/or vacuum dehydration, from through the water of squeezing out the polymeric hipe foam.After pressurization and/or heating, drying and/or vacuum dehydration, these polymeric foams can be in a kind of flat or unexpansive state that contracts.Some flat foams that can not contract also can be used as diffusion material as those flat foams that can not contract of describing in No. 08/542497 U.S. Patent application of common pending trial and No. 5260345 United States Patent (USP).

Super absorbent polymer or hydrogel

Can be randomly, and usually be preferably, super absorbent polymer, perhaps hydrogel can be comprised in the absorbent structure of the present invention.But can be used for aquogel type absorbent polymer among the present invention and comprise the multiple water insoluble basically but polymer of imbibition, it has the ability that absorbs big quantity of fluid.This polymeric material generally also is known as " hydrocolloid " or " super moisture absorption " material.The absorbent polymer of these aquogel types preferably has a large amount of anionic functional groups, as sulfonic group and more typical carboxyl.Be suitable for using the example of polymer herein to comprise the polymer that those are got by the unsaturated acidiferous monomer preparation of polymerizable.

Some non-acid monomers also can be used for the preparation of the absorbent polymer of hydrogels herein type, but account for accessory ratio usually.This non-acid monomer comprises esters for example water miscible or dispersible acidiferous monomer in water, and some do not contain the monomer of carboxyl or sulfonic acid group.In United States Patent (USP) 4,062,817 such as (Westerman people) that U.S. Pat 4,076,663 such as (Masuda people) that the example of this material known was authorized on February 28th, 1978 for example and December in 1977 were authorized on the 13rd description is arranged.

The aquogel type absorbent polymer that is suitable among the present invention contains carboxyl.These polymer comprise the starch-acrylonitrile graft copolymer of hydrolysis, neutral starch-the acrylonitrile graft copolymer of part, starch-acrylate graft copolymer, the neutral starch-acrylate graft copolymer of part, saponified vinyl acetate guanidine-acetic acid-acrylate copolymer, the acrylonitrile of hydrolysis or acrylamide copolymer, the polymer of the slight cross-linked network of any several copolymers in front, the polymer of neutral polyacrylic acid of part and the neutral polyacrylic slight cross-linked network of part.These polymer both can use separately also and can use with the form of two or more different mixture of polymers.The 3661875th, 4076663,4093776,4666983 and No. 4734478 patent disclosures of the U.S. some examples of these polymeric materials.

Being used to make the particulate most preferred polymeric material of aquogel type is the polymer of the slight cross-linked network of neutral polyacrylic acid of part and their starch derivatives.Most preferably, the granule of this aquogel type contain about 50% to about 95%, preferable be the polyacrylic acid (i.e. poly-(sodium acrylate/acrylic acid)) of about 75% neutral, slight cross-linked network.

As mentioned above, the absorbent polymer of aquogel type preferably slight cross-linked network.Cross-linked network plays and makes the water-fast substantially effect of polymer, and has partly determined the content characteristic of the extractible polymer of wettability power and precursor granules and the final macrostructure that forms.No. 4076663 patent of the U.S. of quoting as proof previously and (Dahmen's) German patent DE-A-4020780 have described the preparation method of these cross-linked network polymer and cross-linked network agent commonly used in more detail.

The superabsorbent material can use with particle form or fibers form, and also can mix with other component, forms preformed configuration.

Although the front has been described each independent parts respectively, can form absorbent structure or substructure by one or more this parts are combined.

Several suitable compound modes are described below, but following description does not have restriction:

--special super absorbent polymer (SAP) and cellulose fibre or other fiber mixing.Its ultimate principle firmly sets up already and by known, still, in order to reduce the thickness of articles for use, the weight ratio of present employed SAP and fiber is more and more higher.In this scope, with SAP with combine such as the binding agent of (disclosed) hot-melt adhesive one class as EP-A-0.695.541, perhaps combining with fusible polymeric material (as the PE granule) can be the approach of a kind of proper fixedly SAP;

--SAP is cross-linked to form a kind of substructure by intergranular;

--cellulose SAP and other fiber mixing are got up, and perhaps form a kind of fiber SAP net;

--there is the foaming structure of difference in some at aspects such as pore-sizes.

Improved absorbent device

Described absorbent device and suitable material on the whole, structure after component or the subfraction, will be described below according to concrete technical characterictic of the present invention.Therefore, how the starting point handles the urine of being discharged by different wearer if being to describe, and this absorbent structure handle aspect the urine the performance that should have.

But, should be noted that same liquid handling mechanism is applicable to that also other is the Excreta of main component with water, for example low-down feces of viscosity or menstrual fluid.

Some zones of absorbent device

In general, hygroscopic hygienic article will be through around wearer's the lower body.A basic structural feature of these articles for use is the zones (" discharge area ") that have Excreta to occur that cover on the health, and stretch round corresponding health opening in these zones.Correspondingly, the position with the described discharge area of covering on the absorbent device is called " load region ".Therefore, in use, usually these articles for use are placed on wearer's the body by this way, make their (with regard to standing places of wearer), extend upward simultaneously at the front and back of wearer's body since the crotch portion between two lower limbs.

In general, the length dimension of these class articles for use is greater than their width dimensions, when described articles for use during by user wears, height direction when the axis of its length dimension is in standing state with the wearer is consistent, and its width dimensions is consistent with the collinear direction that the left side from the wearer extends to the right.

Owing to wear the organization of human body of these class article, the space between wearer's two lower limbs define these class article in this zone the space that can be in.Good docile in order to realize, should guarantee that when the design absorbent device it can fit well in the crotch district.If the width of articles for use is excessive for the width of wearer's crotch portion, these articles for use just may be out of shape, and its performance is damaged, and reduce the comfort of bringing to the wearer.

Having minimum widith, be used in that to form best position of fitting between wearer's two lower limbs corresponding with the wearer position of distance minimum between its two lower limb on one's body on the absorbent device, within the scope of the invention, this position is known as " crotch point ".

If the crotch point of articles for use is also not obvious from seeing in shape, the method of then determining this position can be: earlier with these articles for use through the wearer (for example baby who toddles) (this wearer preferably is in standing state) on one's body among its expection use crowd, then with two lower limb coileds 8 fonts of a tensile silk thread round the wearer.Regard the positions corresponding on the articles for use the crotch point of articles for use as, correspondingly, also regard the crotch point that is contained in the absorbent article core in these articles for use as with crossover sites silk thread.

Although the crotch point of this articles for use usually is in the centre (in the vertical) of articles for use, is not must be like this.Fully can with on the articles for use will be through the forward part of health make (on length dimension, perhaps on the width dimensions, perhaps on two sizes of length and width, perhaps on surface area) less than the part that is through health back (or rear portion).Equally, also not necessarily the crotch point to be placed on the centre of absorbent article core, particularly all the more so when absorbent article core is not in the longitudinal middle part of absorbent device.

The crotch district is round the crotch point thereby is covered with corresponding health opening, i.e. that zone of each discharge area.Except as otherwise noted, this regional length accounts for the absorbent article core total length, and (definition of total length is: the front waist edge of absorbent article core and the distance between the back waist edge, can represent front waist edge and back waist edge approx with two straight lines perpendicular to longitudinal midline) 50%: if the crotch point is in the central authorities of articles for use, then (when when the front-end edge of absorbent article core is counted) crotch district originates in 25% of total length, and extends to 75% place of absorbent article core total length.In other words, forward and backward each 1/4th sections of the length of absorbent article core do not belong to the crotch district, and remainder then belongs to the crotch district.

Beyond the crotch district in the first half that is distributed in absorbent device below 50% of final liquid storage capacity in forward part, in the latter half that is distributed in absorbent device more than 50% of described whole liquid storage capacity.Perhaps, beyond the crotch district in the first half that is distributed in absorbent device below 33% of final liquid storage capacity in forward part, in the latter half that is distributed in absorbent device more than 67% of described final liquid storage capacity.

The length in crotch district is that 50% this conclusion of absorbent article core total length draws at baby diaper, and is verified, and this is an a kind of proper approach of describing the liquid handling phenomenon.If the present invention is applied to then may need to reduce these 50% (articles for use that for example are used for serious incontinence) in the articles for use that size differs widely, perhaps improve this ratio (articles for use that for example are used for extremely slight or mild incontinence).More in a broad aspect, it is too many that this crotch district of articles for use should not exceed wearer's discharge area.

If the crotch point is set to the mid point that departs from articles for use, the crotch district must cover 50% of articles for use (in the vertical) total length, still, is not to be evenly distributed between the zone, front and back, but should adjusts pari passu according to the degree that departs from.

With an absorbent article core length overall is that the articles for use that 500 millimeters, crotch point are positioned at central authorities are example, and the crotch district should begin to extend to apart from 375 millimeters places of front-end edge from 125 millimeters of distance front-end edges.Perhaps, if crotch point towards 50 millimeters of the front-end edge of absorbent article core reaches, (that is) apart from 200 millimeters of the front-end edges of absorbent article core, then the crotch district extends to 350 millimeters places from 100 millimeters.

In general, if the absorbent article core total length of an absorbent device is L _c, crotch point is L with the distance of the front-end edge of absorbent article core _Cp, the length in crotch district is L _Cz, the distance of the front-end edge in then described crotch district and the front-end edge of absorbent article core

L _fecz＝L _cp*(1-L _cz/L _c)。

For example, described absorbent device can be the baby diaper that a baby who the confession toddles (being that body weight is about 12 to 18 kilograms baby) wears, and the size of these articles for use is commonly referred to as queen size when selling.Then these articles for use must receive and hold feces and urine, and on meaning of the present invention, the crotch district must mainly bear the work of accepting urine.

The gross area in crotch district and size also depend on the respective width of absorbent article core certainly, that is, if the part of absorbent article core in the crotch district is narrower than its part outside the crotch district, then (table) area in crotch district is less than the area of the remainder of absorbent article core.

Although can expect, the border between the remainder of crotch district and absorbent device also can be curved, and they belong to the collinear scope of the described longitudinal axis perpendicular to absorbent device of this description basically.

" crotch district " also limited by the width of absorbent article core in this respective regions, and " area in crotch district " from the teeth outwards then determined by the length and the corresponding width in crotch district.

As the complementarity parts to the crotch district, absorbent article core also comprises at least one, in most cases is two lumbar regions.Extend front and/or rear towards absorbent article core outside the crotch district, described lumbar region.

Design capacity and maximum storage capacity

In order to compare, have found that " design capacity " is a proper measure to service condition difference or the different absorbent device of size.

For example, the baby is representing a typical colony that uses, but both made in this colony, on the one hand, to the baby who toddles, the number of times of its urine amount, urine, the composition of urine all can be in very large range different, on the other hand from less baby (neonate), in the different babies that toddles, above-mentioned these parameters also can be different.

Another uses colony can be bigger child, and the incontinence of certain form also can take place for they.

In addition, the adult of incontinence also can use these class articles for use, and the degree of its incontinence equally also has a very wide scope, and so-called light incontinence is until serious incontinence.

To discuss at baby big as the baby who toddles below, those skilled in the art can migrate the instruction here to other size at an easy rate to do further discussion.Have found that for this class user, following data foot is representative: each voided volume is 75 milliliters, and each wears the stage isuria 4 times, thereby total voided volume is 300 milliliters in this stage, and the speed of urinating is 15 milliliters/second.

Therefore, the articles for use that can deal with this class demand should have the ability of the urine that absorbs this discharge capacity, will be referred to as " design capacity " in the following discussion.

The liquid of above-mentioned discharge capacity must finally be stored the absorbed of these discharge liquor of body (being moisture wherein at least), even make to have, also have only very small amount of liquid residue absorbent device on the surface of wearers skin." finally " speech represents that on the one hand absorbent device has been worn a kind of like this state of a very long time, represents that on the other hand hygroscopic materials has reached their " finally " capacity after reaching balance with the environment around it.This both can be this class absorbent device residing actual user mode after having passed through wearing for a long time, also can be to a kind of state in the simple testing procedure that material or material component carried out.Because the many steps among considering all have asymptotic dynamic characteristic, when actual capacity reaches one during with the fully approaching value of asymptotic terminal point the certainty of measurement of instrument (for example with respect to), those skilled in the art can expect having reached " finally " capacity at an easy rate.

Owing to can comprise that some are mainly used in the material of final storage of liquids in the absorbent device, and some other is mainly used in realization such as receiving and/or the function of diffusion liquid one class but the material that also may have certain final storage capacity, so, when describing suitable absorbent article core material of the present invention, do not open these functions are discrete artificially.However, still not only can determine the final memory capacity, the memory capacity of hygroscopicity structure in some zones of final memory capacity, the absorbent article core of whole absorbent article core, whenever perhaps even the final memory capacity of substructure, and can determine in the past the memory capacity of used material.

Because the top articles for use that different size is discussed, those skilled in the art can be at an easy rate adopts suitable design capacity at other predetermined use colony.

The capacity distribution form

An importance of the present invention is to be arranged in total absorptive capacity in the zones of different of absorbent device with unique mode, even the amount of liquid that is held in the feasible absorbent device is approaching or reach its design capacity, this absorbent device also can very cosily be fitted on wearer's the body.

Being primarily aimed at of the set-up mode of this uniqueness a little is only to provide very small amount of memory capacity in the crotch district.

The capacity in a concrete zone can be determined by following factor:

--the weight per unit area (how much restraining material with per unit area represents) of the hygroscopic materials considered;

--the absorptive capacity (representing) of material with every what milliliter capacity of gram material;

--the area in described zone, in current discussion, this area is by the longitudinal size and the corresponding width on this dimensional directions (not necessarily constant) decision in zone.

Preceding two factors can be merged into capacity per unit area (representing) with how many milliliters of per unit area.

If any one (being width or weight per unit area or composition) arranged in these parameters is not constant, those skilled in the art can calculate corresponding weighting factor or meansigma methods at an easy rate, for example by earlier to different parameter summations (perhaps integration), and then the relevant parameters of adding up divided by it.

Therefore, a kind of mode of expressing the requirement of this smaller final memory capacity in the crotch district is: the capacity per unit area that limits the crotch district low than in all the other zones of hygroscopicity structure.

The final liquid storage capacity per unit area in crotch district should be not more than 0.9 times of average final liquid storage capacity per unit area of the remainder of absorbent article core, more preferably be not more than 0.7 times of the average capacity per unit area of final liquid storage of the remainder of absorbent article core, more preferably 0.5 times.But, most preferred design even further reduced final liquid storage capacity per unit area in the crotch district, even be brought down below 0.3 times of the average capacity per unit area of final liquid storage of the remainder of absorbent article core.The crotch district both can have uniformly final liquid storage capacity per unit area, also can be made up of some different zonules of final liquid storage capacity per unit area.In a kind of particularly preferred design, the some parts in the crotch district does not have final unit are memory capacity basically, and this class zone account for the whole crotch district gross area 50% in addition more.

Several vertical section of describing another kind of method that the crotch district should have lower this requirement of moisture absorption capacity and be with absorbent article core is the starting point, absorbent article core is divided into these three sections of leading portion, stage casing or back segments, perhaps make the crotch district account for 50% of absorbent article core total length, and other section of this section and absorbent article core is compared.The local final memory capacity in crotch district should be less than 49% of the final memory capacity of whole absorbent article core.More preferably,, in described crotch district, preferably have lower absorptive capacity in order after having held liquid, to have further fit performance, that is, and less than 41% of total absorptive capacity of absorbent article core, perhaps, even more preferably less than 23%.

The method of determining final memory capacity distribution form both can be that the material according to each respective section calculates, and also can be for example by absorbent device being cut into several sections with known length size, determined the absorptive capacity of each section again.

If (as more advanced absorbent device usually adopt) super slurper is used as final storage medium, determine that to the another kind of mode than the requirement of low absorption capacity in the crotch district be according to limiting the capacity of super hydroscopic substance with the similar mode of total moisture absorption capacity discussed above, promptly, capacity in the crotch district be lower than super hydroscopic substance capacity 49%, more preferably be lower than 41%, the most preferably be lower than 23%.

Therefore, can obtain " the reverse distribution " of final absorptive capacity by two kinds of modes different, non-exclusionism:

First kind of mode be, sets about from one constant " basic capacity " running through whole absorbent device, is shaped by making absorbent device, and the area that makes the crotch district obtains this distribution thus less than all the other regional areas.Correspondingly, vertical " the local capacity " in the zone outside the crotch district will be than the height in crotch district.

The second way is, the attenuating from " crotch district " " basic capacity " set about, even for an orthogonal absorbent article core, also can have lower capacity in its crotch district.

Certainly, above-mentioned dual mode is combined to make this distribution steeper.

Except redistributing absorptive capacity, make it away from beyond the crotch district, can also make the liquid storage capacity is not to be evenly distributed between the front and rear.And more desirable mode is to come pondage to distribute according to wearer's the build and the real needs of modal user mode.For example, for the baby diaper of planning to wear, should make the capacity in its proparea be lower than the capacity of back zone by the active active baby that learns to walk.For the time regular meeting bedfast incontinence the adult too, the asymmetric final memory capacity in a kind of rear portion distributes may more useful (describing as EP-A-0.692.232).

In a kind of preferred baby diaper embodiment of the present invention, in the part beyond the crotch district, the final memory capacity that half is following, more preferably the final memory capacity below 1/3rd is set at the front portion, it is front waist region, final memory capacity over half, preferably 2/3 final memory capacity is set at the rear portion of articles for use.

But above-mentioned design means requirement in addition, and the good performance that bleeds back promptly is provided.As described above, the loading zone of absorbent device is usually located in the crotch district.But the liquid storage capacity preferably is in outside the crotch district.Therefore, the liquid of being discharged must be sent to the memory block from loading zone, both can be by having reached this purpose above the speed that liquid enters on the absorbent device with sufficiently high liquid transfer rate, also can reach this purpose by a kind of intermediary liquid handling ability, but can damage the dry and comfortable property towards wearer's surface of absorbent device in no instance, can measure dry and comfortable property by the collagen method of bleeding back after absorbing.

After liquid entered, a major function of absorbent device was to retain these liquid firmly, thereby avoids wearer's skin that excessive hydration takes place.If absorbent device function in this respect is bad, the liquid in the absorbent article core will instead flow on the skin and (also be often referred to as " bleeding back "), and this can produce injurious effects to the situation of skin, for example might cause chafing.

Have found that when collagen bled back test after carrying out absorption described herein, result of the test was qualified less than the performance that 180 milligram hour products are had, but, the product of better performances should have the result less than 80 milligrams, is preferably less than 70 milligrams, more preferably less than 50 milligrams.

In order to realize that this liquid transmits and the intermediate liquid memory property, it is a kind of mechanism commonly used that capillary tube transmits.This mechanism depends on formed capillary tube to a great extent.But this transmission not only needs to overcome certain height, and need have enough big liquid transfer rate.Therefore, suitable material not only must promptly reach for example desired vertical height in vertical wicking test, and the liquid of capacity must be sent to this height.Have found that some useful material is being less than the suction head that liquid can be sent to 8.3 centimetres in time of 13 seconds, perhaps be less than the suction head that is sent to 12.4 centimetres in time of 45 seconds.But the time that not only arrives some height is important, and the flow of 8.3 centimeters preferably be higher than 0.32 milliliters/second/centimetre ², perhaps the flow of 12.4 centimeters preferably be higher than 0.16 milliliters/second/centimetre ²

These requirements are disclosed by european patent application 96108427.4, and this part patent also further discloses the requirement aspect bleeding back property and/or dry and comfortable property of skin and receptivity.But this part patent does not relate to the stickiness problem of articles for use after having held liquid, and therefore, it is to satisfy these performance requirements under the situation that adopts conventional capacity distribution form.

In absorption test described herein, absorbent device to the first time flow of liquid absorption rate preferably greater than 3.5 milliliters/second, more preferably greater than 4.0 milliliters/second, more preferably greater than 4.2 milliliters/second, perhaps, when spraying into liquid the 4th time, absorption rate is 0.5 milliliters/second, more preferably greater than 0.6 milliliters/second, more preferably greater than 0.7 milliliters/second.

Test procedure

Introduction

All tests all are approximately to carry out under 22+/-2 ℃ the temperature and the relative humidity of 35+/-15%.The synthetic urine of using in these test methods is the synthetic urine that known name is called Jayco SynUrine, can be from Jayco Pharmaceuticals Company of Camp Hill, and the Pennsylvania place obtains.The prescription of this synthetic urine is: 2.0g/l KCl, 2.0g/l Na ₂SO ₄, 0.85g/l (NH ₄) H ₂PO ₄, 0.15g/l (NH ₄) ₂H ₂PO ₄, 0.19g/l CaCl ₂And 0.23g/l MgCl ₂All these chemical constituents all are reagent grades.The pH value of this synthetic urine is in 6.0 to 6.4 scope.

Vertical wicking test

The purpose of vertical wicking test is to estimate that a liquid level rises to the needed time of a certain height along vertical (promptly resisting gravity), and the amount of the liquid that is sucked by material in during this period of time.

The principle of this test is, a sample is placed on the sample holder that pin type electrode is housed, and the effect of this sample holder is that sample is fixed on the vertical position, and produces the electric time-keeping signal.Hopper is placed on the balance, thereby can monitors the amount of liquid that absorbs by vertical wicking by sample situation over time.By Ekotec IndustrietechnikGmbH, Ratingen tests (but this instrument is not the essential condition of this test) on a kind of commercially available instrument EKOTESTER that Germany produces, and this instrument can also carry out electron process to data.

Fig. 3 a and b show the equipment of test briefly.

This instrument is mainly made by lucite, and it comprises a hopper 310 and a sample holder 320, and 929 gram test(ing) liquids are housed in the hopper, and liquid level 311 is 17 millimeters.This hopper is placed on the balance 315 that a precision is 0.1 gram, for example the PM3000 type balance of producing by Mettler GmbH.Can randomly shown in the line among the figure 316, this balance and an electronic data acquisition device 324 can be coupled together.

Sample holder is a poly (methyl methacrylate) plate, and its width 330 is 10 centimetres, and length 331 is 15 centimetres, and thickness is approximately 5 millimeters (not shown).Fixture 325 extends to outside these sizes along the direction 332 above becoming in test process, to guarantee in test process and can the base 321 of sample holder accurately can repeatedly be placed into test liquid level in the liquid reservoir 310 along vertical direction (being gravity direction) for above 12 millimeters with a reproducible immersion depth.9 cathode electrode pins are installed on sample holder 320 then, and these 9 electrode needle are lined up triplex row, and the distance 334,335,336 on the base 321 of every row and sample holder is respectively 56 millimeters, 95 millimeters and 136 millimeters.3 electrodes are arranged in every row, and these three electrodes are to each other with 28 millimeters interval 337 equidistant arrangements, and the distance between near the electrode the longitudinal edge 322 and these edges 338 is 22 millimeters.The length of electrode needle is approximately 10 millimeters, and diameter is approximately 1 millimeter, and their end has been fined away some a little, so that be placed on the sample.Electrode needle is made of metal.With another one anode electrode pin 327 be placed on the intermediary cathode electrode pin of bottom line at a distance of 5 millimeters places.Anode pin 327 and 9 cathode needles 326 were linked to each other with a time set 341 for 328 (briefly having drawn 2 cathode needles among Fig. 3 a links to each other with time set with an anode pin), so that can monitor the moment of the closing of circuit between anode and each negative electrode, described closing of circuit is by being caused with electrolyte by the test in the wetted specimen between these electrodes.

Opposite with general step recited above, this instrument is placed in the constant temperature cover, in this constant temperature cover, test, the temperature of constant temperature cover is set at 37 ℃, error is no more than 3 ℃.Test(ing) liquid also is placed in the temperature chamber, places the sufficiently long time, so that liquid reaches constant temperature.

Test(ing) liquid is injected in the hopper 310, makes liquid level 312 reach needed height 311, add/subtract 1 gram liquid as 927.3 grams and reach this height for example by adding predetermined amount of liquid.

Make sample be issued to balance, and when being about to begin to test, it is placed in 37 ℃ the environment at experiment condition (as mentioned above).Equally also be before test, measure sample thickness according to method described below.

With suitable means sample is cut into 10 centimetres of sizes of taking advantage of 15 centimetres, avoid during cutting at cut edge generation pinch effect as far as possible, for example can adopt the sample cutter of producing by JDC Incorporated, perhaps adopt the sharp cutting device of similar dissecting knife, perhaps (more inadvisable) adopts one sharp shears.

Carefully sample is placed on the sample holder, the edge of sample is overlapped with the base 321 and the side 322 of sample holder, that is, sample is not reached outside the flat board of sample holder.Simultaneously, sample must be set level basically, but can not be loaded, that is, neither should make sample form ripple, also should not make it be subjected to mechanical stretching sample.Must be noted that sample is the contact electrode pin only directly, do not contact the poly (methyl methacrylate) plate of clamper.

Then sample holder 320 is placed in the hopper 310 of test(ing) liquid with vertical state, makes the degree of depth 333 that sample holder 320 and sample immerse in the liquid be 12 millimeters just.Correspondingly, the distance 343,338 between electrode and the liquid level 312 at this moment, and 339 be respectively 44 millimeters, 83 millimeters and 124 millimeters.Along with the immersion of sample holder, the reading of balance 315 does not change, and has determined the reading of balance by inserting the sample holder that does not have sample in advance, for example it is decided to be 6 grams.

Should admit, must very accurately sample holder 320 and sample be placed on a side in a kind of aclinal mode, and will put soon, because material one contact liq will begin to absorb and wicking liquid.Framework 350 also is the part of EKOTESTER, can easily the sample holder that has fixture 325 be inserted into wherein, but also can adopt other can realize the device that quick and non-tilting inserts.

After having placed sample, monitor the time dependent situation of reading of balance immediately.Have found that balance is linked to each other with a computerized device 340 has good effect, for example this device can be the part of EKOTESTER.

Go when liquid arrives first, and the electrical connection between anode 327 and the negative electrode 326 is connected, then can utilize any time set to note these time, the time set 341 of EKOTESTER is exactly a ready-made example.Although can carry out further date processing in three time values in the delegation each, further data are generally carried out at the meansigma methods of three electrodes in each row, and it is generally in the scope of meansigma methods+/-5%.

Therefore, the data that produced are:

--after sample is immersed in the liquid, the amount in the different moment by the liquid of absorption of sample, and

--liquid arrives the needed time of a certain height.

From above these data,, can read and note two important numerical value for each height in three height:

The first, the time when the liquid front end arrives corresponding height is unit with the second.

The second, divided by " this time ", divided by " cross-sectional area of determining by the sample width of sample thickness measured value and 10 centimetres ", obtain " accumulative total fluid flow " with the amount of liquid of absorption of sample " when the arriving this height by " again.

Absorption test

With reference to Fig. 4, utilize a pump (by Cole Parmer Instrument., the 7520-00 type pump that Chicago, U.S.A. provide), the speed of 75 milliliters of synthetic urine with 15 milliliters/second is ejected on the absorbent structure 410 from 5 centimetres of eminences more than the sample surfaces.Write down the time that absorbs urine with a timer.Spray repeatedly with 5 minutes injection interval just, in absorbent device, held fully till the urine.Every loading produces a new test data 4 times.

(it both can be a complete absorbent device with test specimen, also can be one by an absorbent article core, top flat and the absorbent structure that egative film is formed) lie in and be arranged in the lucite box (figure only shows on its foam platform 411 of bottom 412.A poly (methyl methacrylate) plate 413 is placed on above the sample, and it is 5 centimetres opening that the middle part of this plate has a diameter, and this opening is positioned on the loading zone of absorbent structure.The cylinder 414 that synthetic urine is complementary with opening by one and is glued on the opening is injected on the sample.Electrode 415 is placed on the dull and stereotyped lower surface, contacts with the surface of absorbent structure 410.Electrode is linked to each other with timer.Load 416 is placed on the dull and stereotyped end face, to simulate for example baby's body weight.At for example 20 kilograms of these common full-sizes, reach about 50 gram per centimeters by placing weight 416 ²The pressure of (0.7 pound/square inch).

Test(ing) liquid is injected in the cylinder, and it can be built up on the end face of absorbent structure usually, thereby with interelectrode circuit turn-on.The pipe that utilizes a diameter to be approximately 8 millimeters is transported to test(ing) liquid on the test assembly from pump, test(ing) liquid abrim always in the described pipe.Like this, when pump was started working, liquid began to leave pipe.At this moment, timer also picks up counting, and the urine that will spray into when absorbent structure absorbs, and when interelectrode electrical connection disconnected, timer stopped timing.

The definition of absorption rate is: the amount of the injection urine that time per unit absorbs.Every once urine to the sample injection all calculated absorption rate one time.Interested especially among the present invention is that four first time in the injection are with last.

This test mainly designs at the product that assessment is commonly referred to as the queen size product, and its design capacity is about 300 milliliters, and corresponding final memory capacity is about 300 milliliters to 400 milliliters.Assess the diverse product of capacity and the said goods (for example supplying the product of adult's usefulness of incontinence) if desired, then needing suitably to adjust some imposes a condition, particularly the amount of liquid that will at every turn spray is adjusted into overall design capacity about 20% of articles for use, and should write down the deviation with the code test scheme.

Collagen after the absorption bleeds back method (with reference to Fig. 5)

Before testing, will be for example from NATURIN GmbH, Weinhein, it is 90 millimeters thin slice that the COFFI board collagen film that Germany buys is cut into diameter, for example cut with a sample cutting machine, then described thin film is placed in the controlled environment of test cabinet (as mentioned above), places 12 hours (all will use tweezers when getting collagen film) at least at every turn.

After the urine of the last injection in the described in the above absorption test is absorbed at least 5 minutes, but no more than 6 minutes the time, cover plate and weight are removed, again with test specimen 520) keep flat carefully on the testing stand.

4 are cut and collagen-based materials 510 that balance is good in advance) to weigh, degree of accuracy is at least 1 milligram, then their centerings is placed on the load(ing) point of absorbent device, and covering a slice diameter again is 90 millimeters, thickness is approximately 20 millimeters poly (methyl methacrylate) plate 530).Weight 540 with one 15 kilograms) puts (also centering is placed) carefully.At 30+/after-2 seconds, carefully weight and poly (methyl methacrylate) plate are removed once more, and then once weigh up the weight of collagen film.

Collagen after this absorbs bleeds back the amount that the resulting result of method is the moisture drawn by collagen film, is unit with the milligram.

Be also noted that, can be according to concrete product type (for example different baby diaper size, the incontinence article of the usefulness of perhaps being grown up, perhaps sanpro) adjusts the scheme of this test, perhaps adjust testing program according to the type of the liquid that is absorbed and the variation of amount, the amount of hygroscopic materials and the variation of size or the variation of pressure applicatory.In case determined after these relevant parameters, it is conspicuous for a person skilled in the art that this class is improved.When consider by adjusted testing program bring as a result the time, according to the statistical method of standard,, can be at an easy rate these relevant parameters of for example determining in an original experiment of product be optimized in conjunction with the boundary condition in actual the use.

The liquid diffusion test

The purpose of liquid diffusion test is to determine the amount of the liquid drawn by certain part or the cored structure of absorbent device.

This test can be applicable to bear the articles for use of load in controlled laboratory environment, for example can carry out this test when the liquid handling capability evaluation test (absorption test as described above) of carrying out other.

This test also can be applicable to the articles for use that had been used, is for example wearing this diaper as the baby, makes these diaper receiving fluids under real service condition, carries out this test after this under suitable sanitary condition during these articles for use of assessment.The diaper receiving fluids and it is assessed between waiting time unsuitable long, be that waiting time is very little to the liquid diffusion influence that the result produced for the scheme of testing in described several example below at least although have been found that.

In order to determine the liquid spread condition in an absorbent structure or the articles for use, earlier the articles for use that held liquid are weighed, then when being easy to keep flat (preferably at the elastic component that has cut off shank thereby) it is set level, mark along its longitudinal axis then and one be divided into four labelling.Then, articles for use are cut off, at this moment not must be noted that liquid is extruded along several lines perpendicular to longitudinal axis.Preferably adopt JCD paper cutter or dissecting knife to reach this purpose.

Weigh up the weight of each section, and obtain the ratio of every section weight and gross weight.

For articles for use, can adjust the weight of gross weight and each section by the dry weight of articles for use with more intense distribution (promptly in the material weight difference in the different sections).In order so to do, can determine " sister's diaper " (that is, and with sample loading mode produced diaper, and, if make on large-scale production line, " sister's diaper " refers to the diaper of producing simultaneously with underproof diaper) each section weight.If whole articles for use also can have different weight, then can further regulate the weight of each section according to this ratio, supposition now, error will be distributed in these sections in proportion.

The result of liquid distribution test is expressed as the percentage ratio that is present in the total amount of the liquid in (for example in the crotch district) in some section.

The measurement of density/caliper/weight per unit area

Sample to certain area of for example downcutting by sample cutter is weighed, and degree of accuracy is at least 0.1%.Measure diameter and be 50 millimeters the thickness of trial zone under the pressure of 550 handkerchiefs (0.08 pound/square inch).Can calculate weight per unit area at an easy rate and (be the weight of per unit area, with gram/rice ²Expression), thickness (with millimeter @550 handkerchief pressure representative), and density (is used gram per centimeter ³) expression.

Tea-bag centrifuge capacity test (TCC test)

Although the TCC test develops at super slurper specially, be easy to it is applied to other hygroscopic material.

What tea-bag centrifuge capacity test was measured is tea-bag centrifuge capability value, and it is an index of the fluid preservation amount in the constant hygroscopic material.

Hygroscopic materials is placed in one " tea-bag ", it is immersed in the sodium chloride solution of a kind of 0.9% (weight ratio), soaked 20 minutes, used centrifuge then centrifugal 3 minutes.The liquid weight of being preserved is exactly the absorptive capacity of hygroscopic materials with the ratio of the initial weight of drying material.

2 liters of distilled water that contain 0.9% (weight ratio) sodium chloride are poured in the tray that is of a size of 5 centimetres of 24 cm x, 30 cm x.The packed height of liquid should be about 3 centimetres.

The tea-bag parcel is of a size of 6.5 centimetres of 6.5 cm x, can buy from the Teekanne of German Dusseldorf.Plastic bag sealing machine for kitchen use (for example VACUPACK2 PLUS that is produced by German Krups) with a standard seals parcel.

, open it the tea-bag partial cut by carefully, weigh up its weight then.About 0.200 gram (being accurate to+/-0.005 gram) hygroscopic material sample is put into tea-bag.With heat sealing machine tea-bag is sealed then.It is called the sample tea-bag.Seal an empty tea-bag again, with it as blank bag.

Then sample tea-bag and blank tea-bag are placed on the surface of saline solution, and are pressed in the solution, make it can moistening fully (tea-bag can float on the surface of saline solution earlier, but subsequently can be moistening fully) with a spatula.Pick up counting immediately.After soaking 20 minutes, sample tea-bag and blank tea-bag are taken out from saline solution, and put into a Bauknecht WS130, in Bosch 772 NZK096 or the similar centrifuge (diameter is 230 millimeters), make each pouch all paste the outer wall of centrifugal basket.The lid of centrifuge is covered, start centrifuge, speed is brought up to 1400 rev/mins rapidly.When the stabilization of speed of centrifuge during at 1400 rev/mins, the starting timer.After 3 minutes, centrifuge is stopped.

Sample tea-bag and blank tea-bag are taken out, weigh respectively.

Calculate the tea-bag centrifuge capacity (TCC) of hygroscopic materials sample according to the methods below:

Sample tea-bag weight after TCC=[(is centrifugal)-(the blank tea-bag weight after centrifugal)-(weight of the hygroscopic materials of doing)] ÷ (weight of dried hygroscopic materials).

And, can also measure the specific part of absorbent structure or whole absorbent device, " part " part of cutting out for example, promptly, the some parts of research absorbent structure or whole absorbent device, thereby the whole width along articles for use cuts it on some points of determining of the longitudinal axis of articles for use.Particularly, can determine " crotch district capacity " according to the definition in " crotch district " recited above.Can also determine " capacity per unit area " (that is capacity in a unit are of the specific region of articles for use) with other cutouts.The size of meansigma methods depends on the size of defined unit are (preferably 2 cm x are 2 centimetres), and certainly, size is more little, and meansigma methods is more little.

Final memory capacity

In order to determine or estimate the final design stores capacity of absorbent device, several different methods has been proposed.

For the present invention, the final memory capacity of supposing articles for use is the final absorptive capacity sum of various piece or material.For these different parts, can adopt various mature technique, as long as they have constant comparison.For example, the tea-bag centrifuge capacity of developing and setting up at super absorbent polymer (SAP) both can be used for this class SAP material, also can be used for other material (as described above).

In case known the capacity of each material, can try to achieve total articles for use capacity by these numerical value (unit is a milliliter/gram) being multiply by the weight of the material that is used for absorbent device.

For not being the material that is exclusively used in final storage of liquids, for example for absorbed layer and similar layer, perhaps since this class material compare with the material that is specifically designed to final storage of liquids and in fact have only low-down capability value, perhaps owing to do not look to this class material load bearing fluid, this class material can be discharged into liquid wherein in the material of other final storage of liquids, so can ignore its final memory capacity.

Several examples and assessment

Diffusion material

For more different structures and material, replaced conventional thin paper with two kinds of materials, for example by the Strepp of Germany, Kreuzau is 22.5 gram/rice according to the weight per unit area of NCB benchmark production ²The high wet strength thin paper.Table 1 has been listed the general liquid transfer characteristic of this class thin paper.

At first, a kind of diffusion material of high flow capacity has been carried out assessing (example 1.1), the manufacture method of this material is: from a kind of chemical adhesion net of wet-laying, the weight per unit area of this net is 150 gram/rice ², density is 0.094 gram per centimeter ³, it is made of the fibre blend that contains following composition:

(accounting for fibre blend weight) chemicosolidifying of 90%, the cellulose of twisting (CS) can be buied the trade mark this fibrid element for " CMC " from the Weyerhaeuser of the U.S.;

The Eucalyptus fiber type of (accounting for fibre blend weight) 10%,

With account for fibre blend weight 2%, by U.S. West Patterson, the commodity that the CytecIndustries of NJ sells Parez by name ^TMPolyacrylamide-glyoxal resin of 631NC comes bonding.

Place it in then between two rollers and carried out the secondary forming processing, the overlapping degree of depth of the crown of two rollers is 0.2 millimeter, and the facewidth is 0.6 millimeter, and at a distance of 1.0 millimeters, No. 96108427.4 patent application in Europe done more detailed description to it.

Also made the wet-laying material (example 1.2) of another kind of heat bonding, manufacture method is: the chemicosolidifying twisted fibers element with 60%, 30% the described Eucalyptus fiber type fiber of chemical adhesion diffusion material recited above (as be used for), and 10% centering type PE skin/PET core bicomponent fibre (is mixed with a kind of nonvolatil hydrophilizing agent in the PE resin, HOECHST CELANESE by the U.S. produces, and the trade mark is Celbond  T255) make.After having carried out conventional wet-laying, utilize the air-flow adhering technique of the routine of U.S. Ahlstrom company that this net is carried out heat bonding, its weight per unit area is 150 gram/rice ², density is 0.11 gram per centimeter ³

When these materials being carried out vertical wicking test recited above, the result is as shown in table 1:

Table 1

Example 1.1 examples 1.2 examples 1.3

13 seconds 45＞210 time (second) of wicking to 8.3 centimetre

45 seconds 165 time (second) of wicking to 12.4 centimetre does not reach

Flow 0.32 0.06＜0.02 in 8.3 centimeters

(milliliters/second/centimetre ²)

Flow 0.16 0.04 in 12.4 centimeters does not reach

(milliliters/second/centimetre ²)

Therefore, compare with the conventional thin paper of example 1.3, example 1.2 has more performance really, but it is next compared with the particularly preferred material in the example 1.1, still wants inferior a lot.

General product description

Although the present invention can be used for the product in the wide range, its good especially effect of (promptly for the diaper of baby's use of 8 kilograms to 18 kilograms, be also referred to as " large size " " diaper) in the baby diaper scope has obtained illustration.For this series products, typical dimensions is the size of PAMPERS BABY DRY PLUSMAXI/MAXI, for example by Procter ﹠amp; The size of the diaper that Gamble company sells in European various countries:

Length width

(directions X) (Y direction)

499 millimeters 430 millimeters of-whole diapers

438 millimeters of-absorbent article cores

115 millimeters of-core ear width

102 millimeters in-core " crotch "

In use, the structure of these articles for use is: its part that extends in the lumbar region is to be fitted on the waist symmetrically basically from the front portion to the rear portion.Crotch point overlaps with " load(ing) point ", and its position (all the same with the girl baby for the boy baby) on absorbent device is moved 4.9 centimetres in the section line of absorbent device towards front waist region, apart from 17 centimetres of the leading edges of absorbent article core.Correspondingly, when from the Attacking Midfielder end (0 centimeters) of absorbent article core towards rearward end (43.8 centimeters) when beginning to calculate, the crotch district extends to 27.8 centimeters from 6.1 centimetres.

These products as example of the present invention derive from commercially available product usually, have done improvement according to the general description in the concrete example then.

The northern softwood gas felt that contains about 20 grams in the storage core of these products, and the super slurper of about 10 grams, for example the trade name that can buy from the Stockhausen GmbH of Germany is FAVOR SXMR 100 section bar material.The theoretical capacity of super slurper is 31 a milliliters/gram, and it and capacity are that the gas felt of 4 milliliters/gram is combined, and make the design capacity of this class absorbent device reach about 390 milliliters.In addition, also have in the absorbent article core one " absorption sticking patch ", it is covered with the storage core on one section 25.4 centimetres length, and this segment length starts from leading edge 28 centimeters from absorbent article core, extends to the rear portion from this some beginning.This piece sticking patch is made by the hardened material of a kind of air lay chemical treatment (CS), and this material is provided by the Weyerhaeuser company of the U.S., and trade mark is " CMC ", and it is about 295 gram/rice that its effect is equivalent to a weight per unit area ²Absorption/diffusion layer.With regard to this example, the final memory capacity of these materials is set to zero, because the supposition meeting siphons away liquid from this absorption/diffusion layer, and the liquid (as described above) that makes this layer to receive again to eject repeatedly.

The design of absorbent article core is such: the mixture of the gentle felt of SAP (on wearer's direction) is covered with a thin pure gas carpet veneer.The shape of absorbent article core is orthogonal basically, and size is 438 millimeters * 115 millimeters, and the place is narrower slightly at the crotch point, and width is 102 millimeters.The weight per unit area of mixed layer has certain distribution form, and its capacity distribution form in the longitudinal direction is as follows haply:

First 1/4th (leading portion) 140 milliliters

Second four/one 130 milliliters

The 3rd 1/4ths milliliters

The 4th 1/4th (back segment) 50 milliliters

The improvement of coating performance

The purpose of first test is to keep the distribution effect again of this individual event parameter of memory capacity.For this purpose, carried out a kind of " stickiness research ", whereby, on breadboard manufacturing equipment, produced two products.At first, produced a benchmark product, purpose is to duplicate commercially available prod recited above, and the difference of it and a back product is not have the absorption sticking patch.

This product is compared with " reverse distribution " project organization (example 2.1), and difference only is capacity distribution form difference, and its capacity distribution form is as follows:

First 1/4th (leading portion) 120 milliliters

Second four/one 70 milliliters

The 3rd 1/4ths milliliters

The 4th 1/4th (back segment) 140 milliliters

In " stickiness research ", these were done test.In this test, to synthesize urine in artificial mode joins in test products and the benchmark product, and, noted several experienced mothers' applying evaluation respectively at dry diaper, the diapers having adorned the diapers of 150 milliliters of synthetic urine and 300 milliliters of synthetic urine are housed.

For each part product, all studied its " integral body " applying when holding synthetic urine to some extent and estimated and " applyings between two lower limbs " evaluation.

The numerical range of described evaluation is to 4 (excellent) from 0 (poor).

Product is used among 17 babies that select at random.

Table 2

Example 1 example 2

Mother's applying evaluation

Whole applying 2.6 2.0

Applying between two lower limbs

When dry 3.0 2.0

In the time of 150 milliliters 2.9 1.9

In the time of 300 milliliters 2.6 1.4

Obviously as seen, the stickiness of the diaper of common distribution form is poorer than the stickiness of the diaper of reverse distribution.

Reverse distribution is to Effect on Performance (mixed core)

But consumer does not want to sacrifice in order to improve stickiness the performance of product.For the influence of estimating that different project organizations produces performance, in breadboard test, product is compared with regard to liquid receptivity and the parameter that bleeds back the height correlation of performance.

For this experiment, on a full-scale Laboratory Production line, some products have been produced, one of them benchmark product has duplicated commercially available product structure (example 3.1), different just replaced the reception sticking patch with a heat adherent synthetic receiving layer of ventilating, described this layer is eccentric PE/PP bicomponent fibre (the code name ESEWA ex Danakion AB with 63%, DK) make a kind of net with 37% common southern softwood slurry with the air-flow method, again that its ventilation is bonding, making its density is 0.04 gram per centimeter ³, weight per unit area is 120 gram/rice ²(example 3.3).Next product is example 3.3 and a kind of combination that distributes at the reverse capacity described in the example 2.1.

The 3rd product (example 3.1) is also to comprise a kind of as example 1.2 described heat bonding wet-laying materials with the difference of last a kind of product.

Table 3

Example 3.1 examples 3.2 examples 3.3

The reverse crotch of capacity distribution reversal portion

Receive material--------all be air-flow method bonded web-----------

The diffusion material wet-laying--all is conventional thin paper----

The air-flow method

Liquid distribution (%)

Crotch portion 58 55 79

Acceptance test (milliliters/second)

Spray 2.9 3.6 3.2 the 1st time

The 4th sprays 0.19 0.10 0.16

Collagen bleeds back (milligram)

Crotch portion 268 283 262

Back 25 72 12

These data show, although reverse distribution itself is really by providing less capacity to improve liquid distribution in the crotch district, this beneficial effect is to bleed back performance, the particularly performance that bleeds back at the rear portion of articles for use by sacrifice to obtain.The material that utilizes a kind of liquid-distribution property to be improved can overcome this defective under the condition of not damaging liquid-distribution property or receptivity.

Diffusion material is to the influence of the absorbent article core of routine distribution

The feature performance benefit of reasonable diffusion material has obtained further illustration in the absorbent article core of reverse distribution.In order to emphasize this effect, the diaper (example 4.2 has same structure with example 2.2) of a routine and the diaper in the example 4.1 are compared, in example 4.1, replaced conventional thin paper with a kind of material that improves diffusion (described in example 1).Table 4

Example 4.1 examples 4.2

Liquid distribution (%)

Crotch portion 91 88

Acceptance test (milliliters/second)

Spray 3.9 4.8 the 1st time

The 4th sprays 0.59 0.82

Collagen bleeds back (milligram)

Crotch portion 60 53

Therefore, the fluid distribution materials that has improved has improved performance really, but it has just changed the diffusion of liquid very limitedly.

The stratiform absorbent article core

Beneficial effect of the present invention has obtained further proof in a test model, in described test model, and the mixed core that the absorbent article core of making on breadboard production line is not made up of super hydroscopic substance and fine hair, but have lamellated structure.

Identical in total structure and the example 3, its absorbent article core in design and the difference made is, the rectangle absorbent structure that forms between the bonding diffusion material with a kind of chemical modification that is clipped in two-layer post forming processing described above by the super hygroscopic powder of 15 grams has replaced mixed uniformly storage core.The width of super moisture absorption lamination is 90 millimeters (centerings), is to adopt the folded technology of a kind of spray glue-line produced, and above mentioned EP-A-0.695.541 has done more detailed description to this method.

For two kinds of (being known as " smooth ") structures, extend on this total length that is stacked in articles for use, the weight per unit area of superabsorbent material wherein is 355 gram/rice ²

For the structure of two kinds of reverse distributions, this lamination from the leading edge of absorbent article core and trailing edge simultaneously towards the crotch district with 500 gram/rice ²Weight per unit area extend 167 millimeters, in a part of remaining 130 millimeters long in the middle part of absorbent device, do not contain super slurper.Because the latter is offset towards the front portion, does not have super hydroscopic substance basically in the part in crotch district.

Table 5

5.1 5.2 5.3 5.4

The capacity distribution reversal is oppositely smooth

The common high flow capacity of diffusion material high flow capacity is common

Meansigma methods meansigma methods meansigma methods meansigma methods

Acceptance test (milliliters/second)

Spray 3.95 2.92 3.91 2.89 the 1st time

The 4th sprays 0.66 0.36 0.73 0.54

Collagen bleeds back (microgram)

Crotch portion 59 118 65 106

The back

Liquid distribution (%)

Crotch portion 56 58 70 73

This table 5 has shown the beneficial effect of good diffusion material to absorbent device again: it shows that also the liquid diffusion is subjected to the positive impact (irrelevant with the material of thin paper or high flow capacity) of reverse distributed architecture.But clearly, the performance that bleeds back of tissue paper product has been subjected to very big influence.

From these experiments, can sum up total conclusion, promptly, a preferred product has very little final memory capacity in the crotch district, comprise the material that a kind of diffusion is good, a kind of fluid distribution materials of high flow capacity preferably, therefore, when coming constant with the reception and/or the value of bleeding back, product still has the better fluid handling property.

Claims (13)

1, a kind of absorbent device comprises an absorbent article core, and described absorbent article core comprises crotch district and lumbar region, and the length in crotch district is half of length of whole absorbent article core,

The final liquid storage capacity in described crotch district is less than 49% of the final liquid storage capacity of whole absorbent article core,

It is characterized in that,

Collagen after the absorption in the crotch district of described absorbent device bleeds back the method measured value less than 180 milligrams.

2, absorbent device as claimed in claim 1 is characterized in that, the collagen after the absorption in the crotch district of described absorbent device bleeds back the method measured value less than 80 milligrams.

3, absorbent device as claimed in claim 1 or 2 is characterized in that, the collagen after the absorption in the crotch district of described absorbent device bleeds back the method measured value less than 70 milligrams.

4, absorbent device as claimed in claim 1 is characterized in that, the collagen after the absorption in the crotch district of described absorbent device bleeds back the method measured value less than 50 milligrams.

5, absorbent device as claimed in claim 1 is characterized in that, the final liquid storage capacity per unit area in described crotch district is less than 0.9 times of the average final liquid storage capacity per unit area of the remainder of absorbent article core.

6, absorbent device as claimed in claim 1 is characterized in that, the final liquid storage capacity per unit area in described crotch district is less than 0.7 times of the average final liquid storage capacity per unit area of the remainder of absorbent article core.

7, absorbent device as claimed in claim 1 is characterized in that, the final liquid storage capacity per unit area in described crotch district is less than 0.5 times of the average final liquid storage capacity per unit area of the remainder of absorbent article core.

8, absorbent device as claimed in claim 1 is characterized in that, the final liquid storage capacity per unit area in described crotch district is less than 0.3 times of the average final liquid storage capacity per unit area of the remainder of absorbent article core.

9, absorbent device as claimed in claim 1 is characterized in that, the final liquid storage capacity in described crotch district is less than 41% of the final liquid storage total capacity of whole absorbent article core.

10, absorbent device as claimed in claim 1 is characterized in that, the final liquid storage capacity in described crotch district is less than 23% of the final liquid storage total capacity of whole absorbent article core.

11, absorbent device as claimed in claim 1 is characterized in that, has at least 50% zone not have final liquid storage capacity in the described crotch district.

12, absorbent device as claimed in claim 1, it is characterized in that, beyond the crotch district in the first half that is distributed in absorbent device below 50% of described final liquid storage capacity in forward part, in the latter half that is distributed in absorbent device more than 50% of described final liquid storage capacity.

13, absorbent device as claimed in claim 12, it is characterized in that, beyond the crotch district in the first half that is distributed in absorbent device below 33% of described final liquid storage capacity in forward part, in the latter half that is distributed in absorbent device more than 67% of described final liquid storage capacity.