CN1177966A - Absorbent foams made from high internal phase emulsiona useful for acquiring and distributing aqueous fluids - Google Patents

Abstract

The invention provides absorbent foams materials that are capable of acquiring and distributing aqueous fluids, especially discharged body fluids such as urine. These absorbent foams combine relatively high capillary absorption pressures and capacity-per-weight properties that allow them to acquire fluid, with or without the aid of gravity. These absorbent foams also give up this fluid efficiently to higher absorption pressure storage materials, including foam-based absorbent fluid storage components, without collapsing. These absorbent foams are made by polymerizing high internal phase emulsions(HIPEs).

Description

The absorbing foams that is used to absorb and distribute aqueous fluid by the High Internal Phase Emulsion preparation

That the application includes is flexible, the absorbing polymer foam materials of little porous, perforate.The application relates in particular to by what High Internal Phase Emulsion prepared can absorb and distribute aqueous fluid, as the absorbent foam of urine.

The exploitation that is used as the high-absorbable absorbent article of disposable diaper, adult incontinent pads and briefs and sanpro such as sanitary towel is the theme with quite high commercial significance.The high-performance absorbing material is provided, as the ability of diaper be developed can absorb, distribute and store a large amount of drainage body fluid, particularly Niao absorbent core or structure ability limited.In this respect, the microgranular absorbing polymeric of some of utilization (material that usually is called as " hydrogel ", " super-absorbent " or " hydro-colloid ") particularly important.Referring to for example US3699103 (Harper etc.), on June 13rd, 1972 authorized, and US3770731 (Harmon), and on June 20th, 1972 authorized, and above-mentioned document discloses and use these particulate absorbing polymerics in absorbent article.Really, the exploitation of high-performance diaper is the direct result of thin absorbent core, and especially when being used in combination with fiber base material, these thin absorbent core have utilized these particle absorbing polymerics can be able to absorb the ability of a large amount of excretory aqueous body fluids.For example, referring to US4673402 (Weisman etc.), on June 16th, 1987 authorized and US4935022 (Lash etc.), authorize June 19 nineteen ninety, they disclose double-deck cored structure, comprise fiber base material and microgranular absorbing polymeric, are used for precision work high-performance diaper.

These microgranular absorbing polymerics are remarkable keeping a large amount of fluids aspect the ability of urine.A representative example of these microgranular absorbing polymerics is lightly crosslinked polyacrylic ester.As many other absorbing polymerics, these lightly crosslinked polyacrylic ester comprise many negatively charged ion (charged) carboxyl that is attached on the polymer backbone.Because seepage force, these charged carboxyls make polymkeric substance can absorb aqueous body fluids just.

Except that seepage force, in comprising many absorbent articles of diaper, also very important based on the sorption of capillary force.The capillary absorption agent is at absorption of fluids and wicking rate, is about to the ability aspect that aqueous body fluid moves to away from initial contact point and can improves good performance.Really, structure is received in above-mentioned double-deck wicking, uses the main tool of fiber base material as capillary transfer, and the aqueous body fluids of initial absorption is moved through absorbent core, and the microgranular absorbing polymeric in its floor that can be placed on absorbent core or the district is absorbed and reservation.

Other absorbing material that can provide capillary fluid to shift is the foam of polymers of perforate.Really, the foam of polymers of some type has been used to actual suction, wicking and/or has kept in the absorbent article of aqueous body fluids.Referring to for example, US3563243 (Lindquist), authorized (the absorption pad that its main absorber is the hydrophilic polyurethane foam sheet material) on February 6th, 1971 as diaper etc., US4554297 (Dabi), authorized on November 19th, 1985 (porous polymer that can be used for the absorbed body fluid of diaper or menstruation product), US4740520 (Garvey etc.), on April 26th, 1988 authorized (containing the absorption composite structure such as diaper, the feminine care products etc. that contain the sponge absorption agent made by the super wicking cross-linked polyurethane foam of some type).

If make properly, the hydrophilic polymer foam of open-celled structure can provide in the high-performance absorbent core and to use desired capillary fluid absorption, conveying and storage characteristics.Contain these foamy absorbent articles and can have desirable infiltration integrity, during whole the wearing of these article, can provide fit sensation, and can reduce the change of shape of article (as uncontrolled expansion, pack) during use.In addition, containing the absorbent article of these foamy structures can be easily with commercial mass production.For example, the absorbent core of diaper can be come out from the punching press of successive foam piece simply, and can be designed to have bigger integrity and homogeneity than absorbing fibrous reticulum.These foams can also be made any desirable shape, or even are configured as the diaper of monolithic.

The existing absorbing foams that is particularly suitable for absorbing product such as diaper by High Internal Phase Emulsion (after this being called " HIPE ") preparation.Referring to for example, US5260345 (DesMarais etc.), on November 9th, 1993 authorized and US5268224 (DesMarsis etc.), mandate on December 7th, 1993.These absorptivity hipe foams provide desirable fluid handling properties, comprise: (a) better wicking and fluid partition characteristic, so that the urine of transfer absorbed and other body fluid, away from initial reception area, and enter untapped equilibrium area in the foamy structure, make like this and have the ability to accept effusive subsequently fluid and (b) stressed, promptly under stressed situation, higher storage volume and higher fluid displacement.These HIPE absorbing foams also are soft enough with user that these absorbent articles the are provided comfort with height; The part goods can be made relatively thin wettingly up to absorbed body fluid.Equally referring to US5147345 (Young etc.), on September 15th, 1992 authorized and US5318554 (Young etc.), on June 7th, 1994 authorized, this patent disclosure contain absorption of fluids/distribution member (these parts can be wetting ability, softness, open celled foam, as melamine-formaldehyde foam (as, the BASOTECT that BASF produces)) with based on the absorbent core of the fluid storage/reallocation parts of the absorbing foams of HIPE.

These should be able to be opened fluid fastly other parts that absorb, separate effectively or be assigned to absorbent core based on foamy absorption/distribution member and get on, and the absorption pressure of these parts is pressed height than the desorb of absorptions/dispense foam.This is separated fluid and is drawn onto performance that other absorbent core components gets on to accept that multiple discharges or suck fluid and protect aspect user's xerosis cutis be important providing.Also should allow absorption/dispense foam as void volume reservoir or buffer zone, the fluid that temporarily stored is extruded from the reservoir part of absorbent core when running into very high pressure in the use of this absorbent article.

With this fluid transfer to other absorbent core components the time, these should be able to be accomplished this point based on foamy absorption/distribution member and can not become closely knit or subside.Also should be easy to accept fluid based on foamy absorption/distribution member, no matter whether the help of gravity is arranged.Foam base absorption/distribution member also should be attractive in appearance, soft and improve structural rebound resilience, and under dry and wet state, all have good outward appearance integrity.

Therefore, people wish to make a kind of suction polymeric foam materials of perforate, especially a kind of absorption hipe foam, and this material (1) can play the effect of absorption/distribution member in absorbent core; (2) allow to have than the desorb of absorption/dispense foam press other absorbent core components of higher absorption pressure that fluid section is shifted and not absorption/dispense foam subside; (3) keep user's xerosis cutis, even in " ejection " even under the state with when bearing pressure; (4) be soft and comfortable for this absorbent article of user, have relative high fluid displacement so that diaper and other absorbent article that effectively utilizes absorbent core components to be provided with (5).

The present invention relates to absorb and to distribute aqueous fluid, especially Pai Fang body fluid polymer foams as urine.These suction polymeric foam materials comprise the hydrophilic soft non-ionic polymers foamy structure with the perforate that is interconnected.This foamy structure has:

A) be less than the synthetic ability of urinating the 5cm height of vertical wicking in about 120 seconds;

B) capillary absorption pressure when 50% capacity (i.e. height) is about 5 to about 25cm;

C) to press when 50% capacity (i.e. height) be about 8 to about 40cm in the capillary desorb;

D) the compression deformation of measuring when limiting pressure for 0.74psi is about 5 to about 85%;

E) free absorptive capacity is about 12 to about 125g/g.

Except that rapid absorption and distribution body fluid, absorbing foams of the present invention can also be discharged into this body fluid other fluid storage parts effectively, comprises that foam base flow body reservoir part gets on.Absorbing foams of the present invention is with high relatively capillary absorption pressure and allow the unit weight volumetric properties (comparing with conventional foam) of its absorption fluids to combine, no matter whether the help of gravity is arranged.Because its softness, resilient structures and apparent integrity, absorbing foams of the present invention also provides good aesthetic.As a result, absorbing foams of the present invention is attractive especially as high-performance absorbent article such as diaper, adult incontinent pads or briefs, sanitary towel or the like.

The feature of a particularly important of foamy of the present invention is can not subside when it is absorbed other parts desorb in the core.Not bound by theory, we think the opposing (that is anti-subsiding) of the compression that this convection cell static pressure causes be since these foams at the desorption pressures of swelling state less than the needed pressure of its compression set.A corresponding key character is, when wetted, even do not reuptake under the fluidic situation at this foam, these foams apply and discharge mechanical pressure after automatically be re-inflated.This means that no matter be by desorb by mechanically compress, perhaps both share and make these foam dehydrations, when expanding or returning to swelling state, these foams all suck air.As a result, these foamy rapid absorption fluidic abilities have been resumed, thereby this foam can provide the exsiccant sensation.

The invention further relates to the water-in-oil emulsion of water of oil phase by the polymerization particular type and relative volume or the method that HIPE obtains these absorbing foams with relatively small amount.This method comprises the steps:

A) under temperature about 50 ℃ or higher and low shear-mixed, form water-in-oil emulsion by following material;

1) oil phase comprises:

A) about 85 to about 98% weight can form the monomer component that Tg is about 35 ℃ or lower multipolymer, this monomer component comprises:

I) about 30 water-fastly basically can form the monofunctional monomer that Tg is about 25 ℃ or lower atactic amorphous polymer to about 80% weight is at least a;

Ii) about 5 at least a water-fast basically simple function comonomers that the toughness toughness about equally that is provided with vinylbenzene can be provided to about 40% weight;

Iii) about 5 the water-fast basically first multifunctional linking agents to about 25% weight, this linking agent is selected from: Vinylstyrene, trivinylbenzene, divinyl toluene, divinyl dimethylbenzene, divinyl naphthalene, the divinyl alkylbenzene, divinyl phenanthrene, divinyl biphenyl, the divinyl ditan, the divinyl benzyl, divinyl phenyl ether, divinyl phenyl thioether divinyl furans, vinyl thioether, divinylsulfone and composition thereof; With

Iv) about 0 the water-fast basically second multifunctional linking agent to about 15% weight, this linking agent is selected from: polyfunctional acrylic ester, methacrylic ester, acrylamide, Methacrylamide and composition thereof; With

B) about 2 to a kind of emulsifying agent component of about 15% weight, this emulsifying agent can be dissolved in the oil phase and be applicable to and form stable water-in-oil emulsion, this water-in-oil emulsion comprises: (i) have first emulsifying agent of at least 40% weight emulsification component, this emulsifying agent component is selected from: linear unsaturated C ₁₆-C ₂₂The diglycerol monoester of lipid acid, branching C ₁₆-C ₂₄The diglycerol monoester of lipid acid, branching C ₁₆-C ₂₄The Glycerol dimer list aliphatic ether of alcohol, linear unsaturated C ₁₆-C ₂₂The Glycerol dimer list aliphatic ether of Fatty Alcohol(C12-C14 and C12-C18), linear saturated C ₁₂-C ₁₄The Glycerol dimer list aliphatic ether of alcohol, linear unsaturated C ₁₆-C ₂₂The anhydro sorbitol monoesters of lipid acid, branching C ₁₆-C ₂₄The anhydro sorbitol monoesters of lipid acid, and composition thereof; Or (ii) having first emulsifying agent of these emulsification components of at least 20% weight and the mixture of some second emulsifying agent, the weight ratio of first emulsifying agent and second emulsifying agent is about 50: 1 to about 1: 4; With

2) comprise a water of the aqueous solution that contains following component: (i) about 0.2 to one of about 20% weight water-soluble ionogen; The (ii) polymerization starter of significant quantity;

3) envelope-bulk to weight ratio of water and oil phase is in 12: 1 to 125: 1 scope; With

B) in the oil phase of water-in-oil emulsion the polymerization single polymerization monomer component to form polymer foams; With

C) alternatively polymer foams is dewatered.

Method of the present invention allows these to absorb and the formation of the absorbing foams of distributing fluids fast, and this is the symphyogenetic result of two factors.A factor is the use of low shear-mixed in the HIPE forming process.Another factor is to allow HIPE under higher relatively temperature, and 50 ℃ or higher temperature form down and the use of the more durable emulsifier system of casting according to appointment.

Figure 1 shows that the absorption curve figure of four kinds of hipe foams of under differing temps, casting in the accompanying drawing.

Figure 2 shows that the desorption curve figure of same four kinds of hipe foams in the accompanying drawing.

Figure 3 shows that a Photomicrograph according to representative absorbing polymeric foamy of the present invention cross section (amplifying 50 times) in the accompanying drawing, this foam is formed 93 ℃ of casting by the HIPE of 60: 1 water weight of oil ratio, wherein the monomer component is 21: 14: 55 by weight ratio: 10 ethyl styrene (EtS): Vinylstyrene (DVB): 2-EHA (EHA): hexanediol diacrylate (HDDA) is formed, and has used single oleic acid double glyceride (DGMO) of 5.5% (oil phase weight) and 1% two fat dimethyl sulfate ammonium methyl emulsifying agents.

Figure 4 shows that foamy Photomicrograph among Fig. 3 (amplifying 250 times) in the accompanying drawing.

The fluid that Figure 5 shows that several hipe foams in the accompanying drawing keeps (desorb pressure) figure line as the function of foam structure (diameter of perforate between abscess).

Fig. 6 and Fig. 7 are depicted as the top view and the side-view of a multilayer absorbent core configuration separately, and wherein fluid storage/reallocation parts are placed on the absorption of fluids/distribution member that is adjacent.

Shown in Figure 8 in the accompanying drawing also is the view that each integral part of the diaper structure of multilayer core configuration arranges, and this multilayer core configuration has a water leakage type absorption of fluids/dispense foam layer, and it is stacked on the fluid storage/redistribution layer with improved water leakage type.

I polymkeric substance absorbing foams

A. foamy general feature

Useful foam of polymers according to the present invention is relative perforate in absorbent article and structure.This means that each abscess of foamy (cell) fully, communicate with adjacent abscess in the clear.These are that abscess in the foamy structure of open-celled structure has perforate or " window " between abscess basically, these perforates even as big as allow fluid easily an abscess from foamy structure transfer in another abscess and go.

These basically the foamy structure of perforate generally all have net-like character, each independently abscess be connected with each other by many interconnective three-dimensional branching nets.The polymeric material fiber yarn that constitutes these branching nets can be called as " pylon ".There is the open-celled structure foam of typical pylon type structure to be shown in by way of example in the Photomicrograph of Fig. 3 and Fig. 4.Concerning any purpose of the present invention, if at least 80% abscess (the size at least 1 μ m) abscess adjacent with at least one is that liquid communicates in the foamy structure, so, this foam materials is exactly " perforate ".

Except being the open-celled structure, these foam of polymers are fully hydrophilic to allow foam to absorb aqueous fluid.The internal surface of foamy structure produces wetting ability by the remaining hydrophilic surfactant active who is retained in the foamy structure after polymerization, or produces by foam treatment process (as described below) after the polymerization of selecting.

The hydrophilicity of these polymer foam structure can quantificational expression, and its method is shown when contacting with absorbable test(ing) liquid with reference to these foams to be gone out " adhesive tension " and measure.The adhesive tension that these foams presented utilizes a kind of method tentatively to determine, this method is to measure the foam sample absorption test liquid of known dimensions and capillary suction specific surface area (capillary suction specific surface area), for example weight of synthetic urine.This method is at common unsettled U. S. application, and the test method of sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to) has partly been made more detailed description, is incorporated herein by reference herein.Generally be that the adhesive tension value is about 15 to about 65 dynes per centimeter as the foam of absorption agent in the present invention, 20 those foams more preferably from about to about 65 dynes per centimeter (it is that 65 ± 5 dynes per centimeter are measured that the amount that sucks synthetic urine by capillary makes surface tension).

Key character of these foamy is its second-order transition temperature (Tg).Transformation intermediate point between Tg representation polymer vitreous state and the rubbery state.It is very high but also very firm and be easy to potentially break to have the foamy body of the Tg higher than use temperature.These foams generally also need the long time of response when using under the temperature that is being lower than polymer Tg.Ideal mechanical property, particularly intensity and rebound resilience need the quite wide monomer type and the range of choice of consumption to reach these desirable performances usually.

For foam of the present invention, as long as this foam has acceptable strength, its Tg should be low as much as possible.Correspondingly, should select to provide the monomer of the homopolymer that has low Tg accordingly as much as possible.The chain length that has been found that alkyl in acrylate and the methacrylate co-monomers can be than the length that Tg foretold from the homopolymer series of homogeneous.Specifically, have been found that alkyl acrylate or methyl acrylic ester homopolymer series have minimum Tg when chain length is 8 carbon atoms.And the minimum Tg of multipolymer of the present invention appears at chain length is 12 carbon atom places.Though (styrene monomer that alkyl replaces can be used for replacing alkyl acrylate and methacrylic ester, and its supply is quite limited at present.)

The shape of the glass transition region of polymkeric substance is also very important, that is to say, this shape (as the function of temperature) is narrow or wide.With the use temperature (normally envrionment temperature or body temp) of polymkeric substance near Tg or Tg, be closely-related.For example, the limited proportionality of broad can mean in the incomplete transformation of use temperature.Usually, if change not exclusively under use temperature, polymkeric substance is firmer significantly and rebound resilience is relatively poor.On the contrary, if change fully under use temperature, polymkeric substance will demonstrate compression reaction faster so.Therefore, wish that the width of the Tg of controlling polymers and its glass transition region is to obtain desirable mechanical property.Generally speaking, the Tg of polymkeric substance preferably is lower than use temperature at least about 10 ℃.(width of Tg and limited proportionality is derived by loss tangent-temperature curve that dynamic mechanical analysis (DMA) measures, and this point is described in the Test Methods section of back.)

B is to absorbing and distributing aqueous fluid and several important foam characteristics of not subsiding

1. vertical wicking

Vertical wicking, promptly the fluid of the fluid wicking specified rate on the direction opposite with gravity in the set time is the performance of the absorbent foam materials particularly important of this paper.These foams are used for absorbent article usually by this way: the fluid of absorption must be in goods from the relatively low position transfer of the absorbent core of goods to higher relatively position.Correspondingly, these foams overcome that gravity wicking fluidic ability is used as absorption of fluids with it in absorbent article and distribution member is relevant especially.

Vertical wicking is to measure by (for example, synthetic urine) the used time of 5cm vertical height of the staining test fluid in the foam test bar wicking pond of measuring specific dimensions.The vertical wicking testing method is at common unsettled U. S. application, and the test method of sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, was incorporated herein by reference herein) has partly been made more detailed description, but at 31 ℃, rather than 37 ℃ are carried out.In order to be used in particular for absorbing in the absorbent article of urine, the sands are running out that the synthetic urine of foam absorber preferred vertical of the present invention wicking (65 ± 5 dynes per centimeter) is 5 centimetres was in about 120 seconds.Preferred foams absorption agent vertical wicking more preferably of the present invention should syntheticly be urinated the sands are running out of 5cm in about 70 seconds, most preferably at no more than about 50 seconds.

2. capillary absorption and desorption pressure

Another key property of useful absorbing foams is its capillary absorption pressure according to the present invention.Capillary is inhaled the foam vertical wicking fluidic ability that is meant of pressing.(referring to " Absorbency " (absorptivity) of P.K.Chatterjee and H.V.Nguyen, Textile Science and Technology (textile technology), the 7th volume, P.K.Chatterjee edits; Elsevier:Amsterdam, 1985; Chapter 2.) for the purposes of this invention, said capillary absorption pressure is meant that the vertical wicking Fluid Volume is 50% o'clock a statical head of free absorbed dose under 31 ℃ of equilibrium conditionss.Statical head is to be represented by the fluid that highly is h (as synthetic urine) post.As shown in Figure 1, for foam of the present invention, this is the weight break point on the typical capillary absorption curve.

Fig. 1 has represented four kinds of foamy absorption curves, and these four kinds of foams are labeled as P161 respectively, P170, P180 and P194, respectively with at 161 °F ℃ (72 ℃), 170 °F (77 ℃), the HIPEs of 180 (82 ℃) and 194 ° (90 ℃) casting is corresponding.Absorption pressure be determine according to these absorption curves and be summarised in the table 1.

Table 1

The pouring temperature absorption pressure (centimetre)

161°F 8

170°F 12

180°F 8

194°F 8

To the ability of the absorbing foams that plays absorption of fluids and distribution member effect of the present invention particularly importantly their capillary desorb press.The capillary desorb is pressed and is meant that foam holds the fluidic ability under 22 ℃ of equilibrium conditionss under different statical heads.With regard to purpose of the present invention, said capillary desorb is pressed and is meant that the absorption of fluids amount is 50% o'clock the statical head (i.e. height) of free absorbed dose under 22 ℃ of equilibrium conditionss.As shown in Figure 2, for foam of the present invention, this is the weight break point on the typical capillary desorption curve.

Fig. 2 has represented same four kinds of foamy desorption curves, and these four kinds of foams are labeled as P161 respectively, P170, P180 and P194, respectively with at 161 °F ℃ (72 ℃), 170 °F (77 ℃), the HIPEs of 180 (82 ℃) and 194 ° (90 ℃) casting is corresponding.Desorb press be determine according to these desorption curves and be summarised in the following table 2.

Table 2

Pouring temperature desorb pressure (centimetre)

161°F 31

170°F 27

180°F 24

194°F 19

With respect to other absorption piece, especially want to be used for the absorption pressure of parts of store fluid, it is important that the capillary desorb is pressed.If the absorption of fluids parts convection cell of absorbent article absorbs sacrifices consisting of an ox, a sheep and a pigly, the ability that these other parts are opened fluid separation will be hindered.This will cause absorption piece loading a large amount of fluids all the time, thus the easier leakage of absorbent article.Foam of the present invention has enough low desorb presses, thereby the fluid storage parts can dry effectively (being desorb) these foams.It is quite dry to accept more fluid " ejecta " (from the user or extrude) and remain close to one deck (top flat) of user's skin from reservoir part that this has recovered the foamy capacity.Data presentation shown in the last table 2 this performance be how by selecting suitable processing conditions (as, pouring temperature) to regulate.

Absorbing foams of the present invention can easily be absorbed the parts desorb of other store fluid in the core, comprise that those comprise the conventional parts that absorb gelatinous material, described in following patent: US5061259 (Goldman etc.), on October 29th, 1991 authorized, US4654039 (Brandt etc.), (on April 19th, 1988 issued again in mandate on March 31st, 1987, Re.32694), US4666983 (Tsubakimoto etc.), on May 19th, 1987 authorized, and US4625001 (Tsubakimoto etc.), on November 25th, 1986 authorized, and all these patents all are incorporated herein by reference; And absorb the absorption macrostructure of gelatinous materials preparation by these, described in following United States Patent (USP): US5102597 (Roe etc.), on April 7th, 1992 authorized, and US5324561 (Rezai etc.), on June 23rd, 1994 authorized, and all was incorporated herein by reference herein.In fact these absorbing foams can be stored the fluidic polymkeric substance absorbing foams desorb that absorbs by other at an easy rate, described in following United States Patent (USP): US5268224 (DesMarais etc.), on December 7th, 1993 authorized; Common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to), with common unsettled U. S. application, sequence number (SN) 08/370922 (Thomas A.Desmarais etc.), submit to January 10 nineteen ninety-five, numbering 5541, all these all are incorporated herein by reference.Correspondingly, absorbing foams of the present invention acts on very good at other that the fluid that absorbs is promptly transferred to absorbing structure under " ejection " situation repeatedly above the fluid storage parts.

The capillary absorption pressure can be used common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc., submitted on December 11st, 1992, be incorporated herein by reference herein) the vertical wicking capacity test described in detail of Test Methods section measure, just at 31 ℃ rather than 37 ℃.The data that vertical wicking capacity (verticle wickingabsorbent capacity) test obtains provide the curve that therefrom draws the capillary absorption pressure.

The capillary desorb is pressed and can be used the method for describing in Test Methods section to measure.For producing the data of desorption curve, with a foam sample water saturation, vertical hanging allows its desorb up to reaching balance then.The absorption of fluids of drawing then amount is as the function curve diagram of height.Curve is determined capillary desorb pressure thus, and promptly the absorption of fluids amount is 50% o'clock a statical head of free absorbed dose.

According to the capillary absorption pressure of suitable absorbing foams of the present invention is about 5 to about 25cm, and the capillary desorb is pressed to about 8 to about 40cm.The capillary absorption pressure of particularly preferred absorbing foams is about 5 to about 15cm, and the capillary desorb is pressed to about 8 to about 25cm.

3. compression distortion

Important mechanical property of foamy of the present invention is that it resists the intensity that compression set (RTCD) is determined by it.The shown RTCD of foam is the polymkeric substance modulus herein, and density and the cancellated function of foam.And the modulus of polymkeric substance is made up of a) polymkeric substance; B) foamy polymerizing condition (for example, polymerization, especially crosslinked whether complete); And c) polymkeric substance is by residual materials, as remaining in the emulsifying agent plastifying degree decision in the foamy structure after the processing.

For the absorption of fluids/distribution member in the absorbent core that is used as absorbent article such as diaper, foam of the present invention must suitably be resisted these absorbing materials and run into caused deformation of power or compression when absorbing and keep fluid.This with fluid from absorption/distribution member be separated to other reservoir part the absorbent core get on (no matter be because the absorption pressure gradient or owing to extrude) time is even more important.Really, absorption/dispense foam of the present invention provides the balance of capillary desorb pressure and foamy body to avoid unnecessary subsiding in the sepn process.

If RTCD and/or its expansion strength again (turgor pressure when being specific compression per-cent) greater than it are pressed in the desorb of foamy capillary, foam will tend to subside when desorb, thereby make foam be in saturated, dense state.In this case, it is moist that absorption/dispense foam feels, thereby cause the humidity of user's skin.This also will hinder the speed of further absorption fluids ejecta.

Yet if foamy body is too high, they will look and feel harder, cause the aesthetic feeling of difference.Equally, foam of the present invention can distribute and a mechanism of separation of the fluid relates to machinery and pumps.Therefore, for absorption/dispense foam, the user in use experiences the extruding of standard atmosphere pressure to a certain degree to promote that this extra separation mechanism is favourable.

The RTCD that foam of polymers of the present invention presented can keep the dependent variable that certain hour produced to quantize under certain qualification pressure by measuring the saturated foam sample.Carrying out the Test Methods section that the method for the test of this particular type narrates in the back describes.The useful foam of absorption agent as absorption and distributing fluids is those opposing compression sets, as present about 5% foam to about 85% compression that typical strain is a foamy structure under qualification pressure 0.74psi (5.1kPa).The preferred strain that produces with this understanding is in 5% to 65% scope, most preferably between 5 to 50%.

4. reply from wet compression

From wet compression reply (RFWC) be meant a wet foam material produce or use the power that produces be returned to the tendency of its initial size or trend (in expansion process again less than from wherein drawing the holder of free fluid) after standing to be out of shape or compress fast.Many high capillary absorption pressure foams as US5268224 (DesMarais etc.), were authorized on December 7th, 1993 and common unsettled U. S. application, and the foam described in the sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to) is difficult for expanding again.Also found absorption/dispense foam and Yan Dangqi when having higher absorption pressure components compete, as typically running in absorbent core, this expands difficult more again.

Test Methods section has proposed test from the regressive proper method of wet compression.Usually this method relates to a foam sample that has been saturated to its free absorptive capacity with synthetic urine has been placed on a high capillary absorption pressure material top, exerts pressure.Sample remain under the constant temperature (31 ℃) 75% the compression under deformation under 5 minutes, shed pressure then.Through two minutes with high absorption pressure material competition fluid (sample existing expansible chance) again after, take away sample and measure its thickness.Regard the regressive degree of thickness of sample as sample from the regressive tolerance of wet compression.

The preferred absorbing foams of the present invention is at least about 60% of its abundant expanded thickness in the answer that release under pressure presents in back 2 minutes usually.More preferably, this class preferred foam is replied and is at least the about 75% of abundant expanded thickness discharging the wet compression that has in back 1 minute under pressure, most preferably at least about 90%.

5. free absorptive capacity

Another key property of absorbing foams of the present invention is its free absorptive capacity." free absorptive capacity " is the total amount that the per unit mass solid sample absorbed of given foam sample is advanced the test fluid (synthetic urine) in its pore structure.Be used for the useful especially foam of absorbent article such as diaper and will satisfy minimum free absorptive capacity at least.In order to be specifically designed in the absorbent article that absorbs urine, the free absorptive capacity that absorbing foams of the present invention should have is that every gram dry foam absorbed is synthesized urine about 12 to about 125g/g, is preferably about 20 to about 90g/g, most preferably is about 45 to about 75g/g.Measuring the method for the free absorptive capacity of foam describes in the Test Methods section of back.

C. other performance of foam of polymers

1. the diameter of abscess (cell) and perforate (hole sizes)

Can be used for limiting feature of preferred polymers foamy is its foam structure.The foamy abscess, especially surround relative monomer-free the water drop contain the abscess that monomeric oil phase is polymerized, be spheric usually basically.These spherical abscesses interconnect by opening (back is called hole between bubble).The diameter of opening (perforate) usually is used for characterizing synoptically foam between the size of these spherical abscesses or " diameter " and abscess.Because perforate need not be same approximately size between abscess in the sample of given foam of polymers and bubble, therefore, the size of average abscess and perforate, the diameter of promptly average abscess and perforate usually will be described.

The diameter of abscess and perforate is the parameter that can influence many important mechanics of foamy according to the present invention and use properties (comprise these foamy fluid wicking properties, and the capillary that forms in the foamy structure being pressed).Many technology all can be used to measure the diameter of average abscess of foamy and perforate.Useful technology comprises the simple measurement of taking a picture based on the scanning electronic microscope of foam sample.For example Fig. 3 and 4 shows according to typical hipe foam structure of the present invention.Be superimposed upon on the microphotograph of Fig. 4 is 20 microns long scales of expression.This scale can be used for measuring the diameter of average abscess and perforate by image analytical method.The preferred number average cell size of foam that is used to absorb the absorbing material of aqueous body fluids according to the present invention is about 20 to about 200 microns, is generally about 30 to about 130 microns, and the diameter of number average perforate is about 5 to about 30 microns, is generally about 8 to about 25 microns.

Relation between fluid save power and these hipe foams is shown in Fig. 5.Fig. 5 represents the graph of a relation of the diameter of the desorb pressure of a series of hipe foams and number average perforate.As mentioned above, foamy desorb pressure of the present invention is a principal element that stops these foams to subside when desorb or dehydration.Fig. 5 has represented an aspect (diameter of perforate between bubble) of foamy structure is how to influence this key property.Really, as shown in this figure, along with the increase of the diameter of number average perforate, desorb is pressed and is basically that straight line reduces.

2. capillary sucks specific surface area

" capillary suction specific surface area " is the tolerance of the surface-area that the test fluid of the derivatized polymers that test fluid can be approaching can be approaching.Capillary sucks specific surface area and measures by the density of unitary size of the abscess in the foam and polymkeric substance, therefore, and a kind of mode of the total amount of capillary the sucks specific surface area solid surface that to be the participation that provided by the foam reticulated structure of tolerance absorb.

With regard to purpose of the present invention, betide amount that capillary in the foam sample of known quality and size absorbs low surface tension liquid (as ethanol) by measurement and measure capillary and suck specific surface area.At common unsettled U. S. application, the test method of sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, was incorporated herein by reference herein) is partly described this method of measuring the foam specific surface area with the capillary inhalation in detail.Being used to measure any other rational alternative method that capillary sucks specific surface area also can use.

The foamy capillary that is used for absorption agent of the present invention sucks specific surface area and is at least about 0.2m ²/ g.Generally, capillary suck specific surface area about 0.3 to about 4m ²In/g the scope, preferably about 0.3 to about 2.5m ²/ g, most preferably about 0.3 to about 1.5m ²/ g.

3. the surface-area of every lather volume

When the specific surface area of every lather volume can be used to define desorb empirically,, do not subside or remain on the foamy structure of dense state as dry or in the dampness compression.Referring to common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc. submitted on December 11st, 1992, were incorporated herein by reference herein) is wherein described the specific surface area of the every lather volume of closely knit foam in detail." specific surface area of every lather volume " used herein is meant that the capillary of foamy structure sucks the foam density that specific surface area multiply by swelling state.What have been found that the maximum capillary of some every lather volume sucks the value of specific surface area and foamy structure remains on swelling state when desorb, or it is relevant to be returned to the ability of swelling state after dampness is compressed fast.Every lather volume specific surface area that foam according to the present invention has is about 0.06m ²/ cc or littler is preferably about 0.01 to about 0.04m ²/ cc most preferably is about 0.01 to about 0.03m ²/ cc.

4. foam density

Indication " foam density " is meant the foamy gram number in every cubic centimetre of lather volume of air drying foam herein.The same with capillary suction specific surface area, foamy density can influence the many use propertieies and the mechanical property of absorbing foams.Comprise receptivity and foamy compressive set characteristic to aqueous body fluids.

Provide any suitable gravimetric analysis method of the solid foam material quality of the foamy structure of measuring per unit volume can be used for measuring foamy density.For example, common unsettled U. S. application, the test method part of sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, was incorporated herein by reference herein) ASTM gravimetry in greater detail is a kind of method that can be used for measuring density.The dry density value that has as the foam of polymers of the present invention of absorption agent is about 0.0079 to about 0.077 grams per milliliter, preferably 0.011 to about 0.028 grams per milliliter, most preferably about 0.013 between about 0.022 grams per milliliter.

II prepares foam of polymers by HIPE

The A general introduction

The polymerization that is commonly referred to as " HIPEs " by some water-in-oil emulsion with higher water and oil phase ratio in the present technique field can prepare foam of polymers of the present invention.After this be called " hipe foam " from the polymer foams that these letex polymerizations generated.

With many other parameters, structure, mechanical property and the use properties aspect of the foam of polymers that generates for decision are important with the relative quantity of water that generates the HIPE emulsion and oil phase.Specifically, can change inversely with final foam density, and can influence the size of abscess-size and foamy capillary suction specific surface area and formation foamy pylon at the ratio that generates foamy emulsion Zhong Shui and oil.Being used for preparing the common water of the emulsion of hipe foam of the present invention and the envelope-bulk to weight ratio of oil phase is about 12: 1 to 125: 1, and the most frequently used is about 35: 1 to about 90: 1.Particularly preferred polymer foams can by ratio be about 45: 1 to about 75: 1 HIPEs preparation.

1 oil phase components

The oil-continuous phase of HIPE emulsion comprises some monomers that polymerization generates solid foam structure.This monomer component is mixed with, and to form Tg be about 35 ℃ or lower, be generally about 15 ℃ to about 30 ℃ multipolymers (method by dynamic mechanical analysis (DMA) test Tg is described in Test Methods section after this).This monomer component comprises: (a) at least a Tg is that the monofunctional monomer of about 25 ℃ or lower atactic amorphous polymer (is seen Brandup, J.; Immergut, " Polymer Handbook " (polymer handbook) of E.H., second edition, Wiley-Interscience, New York, NY, 1975, III-139); (b) at least a simple function comonomer is used for improving foamy toughness or resistance to tearing; (c) a kind of first multifunctional linking agent; (d) the optional a kind of second multifunctional linking agent.The particular type of the monomer of simple function and comonomer and multifunctional linking agent and the selection of amount have the desired combined of structure, mechanical property and fluid handling properties to realizing, are important so that these materials are suitable for use among the present invention.

The monomer component comprises one or more monomers, and it makes the polymer foam structure of generation have the character of rubber like.These monomers can generate high molecular (more than 10000) and gamma transition transition temperature at about 25 ℃ or lower atactic amorphous polymer.Such monomer comprises, for example, and C ₄-C ₁₄Alkyl acrylate, as butyl acrylate, Ethyl acrylate, Octyl acrylate, 2-EHA, vinylformic acid ester in the ninth of the ten Heavenly Stems, decyl acrylate, dodecylacrylate (lauryl), isodecyl acrylate, vinylformic acid ester in four last of the ten Heavenly stems, aryl acrylate and alkyl acrylate aromatic ester such as benzyl acrylate, vinylformic acid nonyl phenyl ester, methacrylic acid C ₆-C ₁₆Alkyl ester, as N-Hexyl methacrylate, Octyl methacrylate, nonyl methacrylate, lauryl methacrylate (lauryl), decyl-octyl methacrylate, isodecyl methacrylate, methacrylic acid ester in four last of the ten Heavenly stems, C ₄-C ₁₂Ring-alkylated styrenes, as right-n-octyl ethene, acrylamide such as N-octadecyl acrylamide, isoprene, divinyl, and these monomeric combinations.In these monomers, isodecyl acrylate most preferably, dodecylacrylate (lauryl), 2-EHA.The common compositing monomer component of monofunctional monomer weight 30% to about 80%, more preferably 50% to 65%.

The monomer component that uses in the oil phase of HIPEs also comprises one or more can provide the toughness that is provided with vinylbenzene roughly suitable flexible simple function comonomer to the polymer foam structure that generates.More tough foam presents the ability of the deformation that does not have damage basically.These simple function comonomer type can comprise comonomer (as vinylbenzene and ethyl styrene) or other monomer type such as the methyl methacrylate (its homopolymer is typical flexible example) of styrene-based.Preferred such simple function comonomer is based on cinnamic monomer, and vinylbenzene and vinylstyrene are most preferred such monomers.Simple function " toughness reinforcing " comonomer account for usually monomer component weight about 5 to about 40%, preferred about 15 to about 25%, most preferably from about 18 to about 24%.

In some cases, " toughness reinforcing " comonomer also can make subject polymer have the performance of desirable rubber like.C ₄-C ₁₂Ring-alkylated styrenes, especially right-n-octyl ethene is the example of this comonomer.For these comonomers, its amount that is used for the monomer component is the total amount of typical monomers and comonomer.

The monomer component also comprises first (with alternatively second) multifunctional linking agent.With monofunctional monomer and comonomer, the selection of the linking agent of particular type and amount is considerable to final realization of the combination of polymers foamy that preferably has desirable structure, mechanics and fluid handling properties.

The first multifunctional linking agent can be selected from the monomer that contains two or more active ethylene group groups widely, as Vinylstyrene, and trivinylbenzene, divinyl toluene, divinyl dimethylbenzene, divinyl naphthalene, the divinyl alkylbenzene, divinyl phenanthrene, divinyl biphenyl, the divinyl ditan, divinyl benzyl, divinyl phenylether, the divinyl diphenylsulfide, divinyl furans, vinyl thioether, divinylsulfone, and composition thereof.Vinylstyrene is usually to obtain with the form of ethyl styrene in the mixture of about 55: 45 ratio.Can adjust these ratios to enrich oil phase with one or another kind of component.Usually, it is favourable enriching mixture with ethyl styrene component (reducing the amount of vinylbenzene in monomer mixture simultaneously).The ratio of Vinylstyrene and ethyl styrene is preferred about 30: 70 to about 55: 45, most preferably is 35: 65 to about 45: 55.The use of the ethyl styrene of high level makes the multipolymer of generation have required toughness (toughness of being brought with vinylbenzene is suitable) and does not increase its Tg.In the oil phase of HIPE the amount of this contained first linking agent be generally monomer component weight about 5% to about 25%, more preferably about 12 to about 20%, most preferably be about 12 to about 18%.

Optional second linking agent can be from polyfunctional acrylic ester, methacrylic ester, and acrylamide is chosen in Methacrylamide and composition thereof.These linking agents comprise two-, three-and four-acrylate, and two-, three-and four-methacrylic ester, two-, three-and four-acrylamide, two-, three-and the mixture of four-Methacrylamide and these linking agents.Suitable acrylate and methacrylic ester linking agent can be derived from glycol, and three pure and mild tetrols comprise decamethylene-glycol, 1, the 8-ethohexadiol, 1,6-hexylene glycol, 1, the 4-butyleneglycol, 1,3 butylene glycol, 1,4-but-2-ene glycol, ethylene glycol, Diethylene Glycol, TriMethylolPropane(TMP), tetramethylolmethane, quinhydrones, pyrocatechol, Resorcinol, three polyoxyethylene glycol, polyoxyethylene glycol, Sorbitol Powder or the like (acrylamide and methacryloyl amine crosslinker can be derived from corresponding diamine, triamine and tetramine).Preferred glycol has at least two, and more preferably at least 4,6 carbon atoms most preferably.In the oil phase of HIPE the amount of this second linking agent be generally monomer component weight about 0% to about 15%, be preferably about 0 to about 13%.

Not bound by theory, we think, compare with first or second linking agent of independent use comparable measure, and this second linking agent produces the crosslinking structure of the more homogeneous that can more effectively form intensity.This second linking agent also has the effect that glass-the rubber limited proportionality broadens that makes.The limited proportionality of this broad can be regulated to satisfy certain strength and answer requirement under the use temperature by the amount of controlling two used type of crosslinking agent.Therefore, the foam that only contains first type of linking agent will demonstrate the limited proportionality of relative narrower.The amount that increases by second linking agent can make the limited proportionality broaden, though actual transition temperature itself does not change.

The major portion of HIPE emulsion oil phase comprises above-mentioned monomer, comonomer and linking agent.These monomers, comonomer and linking agent must be water-fast basically, so they mainly are dissolved in oil phase, and do not dissolve at aqueous phase, and this point is very important.Use these water-fast basically monomers to guarantee to make the HIPE emulsion that obtains have suitable feature and stability.Certainly, the particularly preferred type of used monomer, comonomer and linking agent is that to make the foam of polymers of generation be suit avirulent and suitable chemical stability is arranged.If these monomers, comonomer and linking agent exist with very low residual concentration between the foam after polymerization processing and/or usage period, the preferred low toxicity or do not have toxicity of these residuals so.

Another main component is the emulsifying agent component in the oil phase, and it allows to generate stable HIPE emulsion.This emulsifying agent component comprises first emulsifying agent and second emulsifying agent alternatively.The first suitable emulsifying agent is: (1) can be dissolved in the oil phase of HIPE; (2) provide minimum oil phase/aqueous phase interface tension force (IFT), for about 1 to about 10 dynes per centimeter, preferred about 2 to about 8 dynes per centimeter; (3) provide critical aggregate concentration (CAC) to be about 5% weight or littler, preferred 3% weight or littler; (4) be formed on that (as formation and the polymerization temperature of HIPE) quite stable does not have coalescent HIPEs under suitable size droplet diameter and the suitable processing conditions; (5) preferably have " interfacial activity " component of high density, this component can reduce oil phase among the HIPE and the interfacial tension between the water.Not bound by theory, we think that the concentration of interfacial agent component should be enough high with at preferred particle diameter, and inner oil phase small droplets individual layer covering at least basically is provided under water-oil ratio and the emulsifier concentration.We also think, the combination of high minimum oil phase/water IFT and low CAC helps being used for forming the formation of the stable HIPE with suitably big particle diameter that the foam with diameter of preferred average abscess and perforate of the present invention uses.Usually, these emulsifying agents: (6) have fusion and/or solid-liquid crystal phase transition temperature is about 30 ℃ or lower; (7) be water dispenser; (8) water insoluble basically or not obvious distribution water inlet phase under working conditions at least.The preferred first emulsifying agent component provides enough wettabilitys being coated on hydrophobic surface (as, foam of polymers) when going up, thus its to the preceding contact angle of synthetic urine less than (preferably much smaller than) 90 °.The method of IFT and CAC of measuring is described in Test Methods section subsequently.

When using especially separately, first emulsifying agent generally includes at least about 40%, preferably at least about 50%, most preferably at least about the 70% emulsifying agent component that is selected from following component: linear unsaturated C ₁₆-C ₂₂The diglycerol monoester of lipid acid, branching C ₁₆-C ₂₄The diglycerol monoester of lipid acid, branching C ₁₆-C ₂₄The Glycerol dimer list aliphatic ether of alcohol, linear unsaturated C ₁₆-C ₂₂The Glycerol dimer list aliphatic ether of alcohol, linear saturated C ₁₂-C ₁₄The Glycerol dimer list aliphatic ether of alcohol, linear unsaturated C ₁₆-C ₂₂The anhydro sorbitol monoesters of lipid acid, branching C ₁₆-C ₂₄The anhydro sorbitol monoesters of lipid acid, and composition thereof.Preferred first emulsifying agent comprise single oleic acid double glyceride (as, be preferably greater than about 40%, more preferably greater than about 50%, most preferably greater than single oleic acid double glyceride of about 70%) and single oleic acid Isosorbide Dinitrate (as be preferably greater than about 40%, more preferably greater than about 50%, most preferably greater than single oleic acid Isosorbide Dinitrate of about 70%), with single Unimac 5680 double glyceride (as, be preferably greater than about 40%, more preferably greater than about 50%, most preferably greater than single Unimac 5680 double glyceride of about 70%).

The diglycerol monoester that is used as the linear saturated and branching lipid acid of emulsifying agent of the present invention can adopt method well known in the art, by preparing with the fatty acid esterification Glycerol dimer.Referring to for example common unsettled U. S. application, the disclosed method for preparing the polyglycerol esters class in the sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, was incorporated herein by reference herein).Glycerol dimer can have been bought or separate from the poly-glycerine class that is rich in Glycerol dimer.Linear unsaturated and branching lipid acid can have been bought.The mixed ester product of esterification can go out to be rich in the fraction of diglycerol monoester through the one or many vacuum fractionation.For example, can use ACMS-15A (C.V.C.Products Inc.; Rochester, N.Y.) continuous 14 inches centrifugal molecular stills come fractionation.Usually, in when heating, the metering earlier of polyglycerol esters raw material is by a removal unit, sends into then in the conical bobbin of heating fumigators of distiller and carries out vacuum distilling.Overhead product is collected on the hood-shaped surface of pin, and this surface energy heating is beneficial to remove overhead product.Overhead product and resistates are seen off continuously by transferpump.Lipid acid component in the resulting mixed ester product can use the high resolving power gas-chromatography to determine.Referring to for example common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, was incorporated herein by reference herein).The distribution of poly-glycerine and polyglycerol esters can decide by the overcritical chromatogram of kapillary in the gained mixed ester product.Referring to common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, was incorporated herein by reference herein).

It is saturated also can to prepare linearity, and linear unsaturated or branching Glycerol dimer list aliphatic ester, its composition can adopt method well known in the art to determine.Also referring to common unsettled U. S. application, sequence number (SN) 08/370920 (January 10 nineteen ninety-five, submissions such as Stephen A.Goldman, numbering 5540) is incorporated herein by reference herein.

Method preparation well known in the art can bought or adopt to linear unsaturated and anhydro sorbitol monoesters branching lipid acid.Referring to for example US4103047 (Zaki etc., on July 25th, 1978 authorized, and was incorporated herein by reference) herein, especially from the 4th hurdle, the 32nd walks to the 5th hurdle, 13 row.Mixed dehydration sorbitol ester product can vacuum fractionation be rich in the component of dehydration sorb monoesters with generation.The Isosorbide Dinitrate component can be identified with method well known in the art, as the small molecules gel permeation chromatography.Referring to common unsettled U. S. application, sequence number (SN) 08/370920 (nineteen ninety-five submissions such as Stephen A.Goldman on January 10, numbering 5540), this article has been described this method and has been used for the poly-glycerine aliphatic ester.

When these first emulsifying agents and some second emulsifier mix were used, first emulsifying agent can comprise a spot of these emulsification components, promptly is low to moderate these emulsifying agent components of about 20%.These second emulsifying agent components be dissolved in oil phase altogether with first emulsifying agent at least and can add so that: (1) increases the water droplet cohesion of stability to prevent to distribute of HIPE, especially when higher water-oil ratio and higher HIPE formation and polymerization temperature, (2) improve minimum oil phase/water IFT, (3) CAC of reduction emulsifying agent component, or (4) increase the concentration of interfacial activity component.Not bound by theory, we think that the ability of low CAC of the high oil phase of keeping of second emulsifying agent/water IFT and emulsification component has enlarged formation and the pouring temperature scope (50 ℃ or higher according to appointment) of HIPE, under this temperature range, can form the HIPE of stable high water-oil ratio, this HIPE has the big drop size that is suitable for forming the foam of polymers with preferred average abscess of the present invention and hole dimension.The second suitable emulsifying agent can be cationic, comprises long-chain C ₁₂-C ₂₂Two aliphatic series, short chain C ₁-C ₄Two aliphatic quaternary ammonium salt such as Quaternium 48s, two (three decyls) alkyl dimethyl ammonium chlorides and two fat dimethyl sulfate ammonium methyls, long-chain C ₁₂-C ₂₂Dialkoxy (alkenyloxy)-2-hydroxyethyl, short chain C ₁-C ₄Two aliphatic quaternary ammonium salts are as two fatty acyl groups-2-hydroxyethyl dimethyl ammonium chloride, long-chain C ₁₂-C ₂₂Two aliphatic imidazoline quaternary ammonium salts such as methyl isophthalic acid-acyl amino-ethyl-2-fat tetrahydroglyoxaline methyl sulfate and methyl isophthalic acid-oleoyl amido ethyl-2-oleoyl tetrahydroglyoxaline methyl sulfate, short chain C ₁-C ₄Two aliphatic series, long-chain C ₁₂-C ₂₂Monoester family benzyl quaternary ammonium salt such as dimethyl stearyl benzyl ammonium chloride; Anionic comprises the C of sulfo-Soduxin ₆-C ₁₈The dioctyl ester of two aliphatic esters such as sulfo-Soduxin and sulfo-Soduxin two three the last of the ten Heavenly stems ester and the mixture of these second emulsifying agents.Method preparation well known in the art can bought or adopt to these emulsifying agents.Preferred second emulsifying agent is: two fat dimethyl sulfate ammonium methyls and two fat Dimethyl Ammonium methyl chlorides.When these optional second emulsifying agents were used for the emulsifying agent component, the weight ratio of first and second emulsifying agent was about 50: 1 to about 1: 4, preferred about 30: 1 to about 2: 1.

Generate the employed oil phase of HIPE emulsion and comprise about 85 to the monomer component of about 98% weight and the emulsifying agent component of about 2 to 15% weight.Preferred oil phase comprises the monomer component and the about 3 emulsifying agent components to about 10% weight of about 90 to 97% weight.Oil phase can comprise other optional composition.A kind of such optional components is the oil-soluble polymerization initiator of the known general type of those skilled in the art, as described in the US5290820 (Bass etc. authorized on March 1st, 1994, were incorporated herein by reference) herein.Another kind of preferred optional component is an antioxidant, as interrupted amine photostabilizer (HALS) and hindered phenolic stablizer (HPS) or any other can be compatible with used initiator system antioxidant.Other optional components comprises softening agent, filler, tinting material, chain-transfer agent, dissolved polymers or the like.

2. water component

The aqueous solution that normally contains one or more dissolved constituents in the discontinuous water of HIPE emulsion mutually.A kind of main dissolved constituent of aqueous phase is water miscible ionogen.The dissolved ionogen makes main oil-soluble monomer, and comonomer and linking agent are reduced to minimum in aqueous phase dissolved trend.Conversely, during letex polymerization, this degree that makes polymer materials be full of the oil/water termination place hole window that is generated by the water drop again reduces to minimum.Therefore, the ionic strength of the water of electrolytical existence and generation be considered to determine the preferred polymers foam that generates whether perforate and perforate to what degree.

Any ionogen that can make water have ionic strength all can use.Preferred ionogen is a monovalence, divalence and tervalent inorganic salt, muriate, nitrate and the vitriol of for example water miscible halogenide such as basic metal and alkaline-earth metal.The example comprises sodium-chlor, calcium chloride, sodium sulfate and sal epsom.Calcium chloride most preferably uses in the present invention.Usually, the electrolyte concentration as HIPE emulsion aqueous phase is about 0.2 to 20% of a water weight.More preferably ionogen accounts for 1 to about 10% of water weight.

The HIPE emulsion also comprises polymerization starter usually.This initiator composition adds the aqueous phase of HIPE emulsion usually, and it can be the water-soluble radical initiator of any routine.This type of substance comprises superoxide such as Sodium Persulfate, potassium and ammonium salt, hydrogen peroxide, peracetic acid sodium, SPC-D etc.Also can use redox initiator system commonly used.Such system combines with reductive agent such as sodium bisulfite, L-xitix or ferrous salt by aforesaid superoxide and generates.

Initiator content can be up to about 20 moles of % (in the total mole number of polymerisable monomer in the oil phase).Preferred initiator content is about 0.001 to about 10 moles of % (in the total mole number of polymerisable monomer in the oil phase).

3. but the salt of hydrophilic surfactant and aquation

The polymkeric substance that forms the hipe foam structure does not preferably have polar functional group basically.This means that foam of polymers is hydrophobic relatively in nature.These hydrophobic foams can absorb hydrophobic fluidic place at needs and find purposes.Such use is included in that the oiliness component mixes with water and when needing the oiliness component separated and keep apart, leaks as marine oil.

If these foams are used for absorbing aqueous fluid, as the fruit juice of splashing, milk etc. need further to handle, so that foam is more hydrophilic relatively to reach cleaning and/or body fluid as urine usually.If desired, the foamy hydrophilic interaction generally is to realize by handling the hipe foam structure with hydrophilic surfactant in the mode of hereinafter describing in detail.

These hydrophilic surfactants can be any materials that can improve the wettability of polymer surfaces.They are known in the present technique field, and it can comprise a lot of tensio-active agents, preferred non-ionic type.They use with liquid form usually, can dissolve or are distributed in the hydrophilic solution that is applied to the hipe foam surface.By this way, the hydrophilic surfactant active can be absorbed by preferred hipe foam, and its amount is suitable to give these surfaces enough wetting abilities, but does not change desirable flexibility of foamy and compression set basically.These tensio-active agents comprise those of emulsifying agent of all above-mentioned oil phases as the HIPE emulsion, as the Glycerol dimer monooleate, and anhydro sorbitol monooleate and Glycerol dimer list isostearate.In the preferred foam, the hydrophilic surfactant active mixes foamy structure, and the residual quantity that is retained in the hydrophilic surfactant active in the foamy structure is about 0.5% to about 15%, preferred about 0.5% to about 6% of a foam wt.

But another material that mixes the hipe foam structure usually is hydration, water-soluble inorganic salt preferred suction or moisture absorption.These inorganic salt for example comprise acceptable alkaline earth salt on the toxicology.The purposes that such salt and they combine with oil soluble surfactant as the foam hydrophilic surfactant has more detailed description in US5352711 (DesMarais, on October 4th, 1994 authorized), its disclosure this paper is incorporated herein by reference.Preferred such salt comprises the halogenide such as the calcium chloride of calcium, and as previously mentioned, it also can use with the electrolytical form of HIPE water.

But the inorganic salt of hydration can mix foam of polymers at an easy rate by handling foam with the aqueous solution of these salt.But the solution of hydrated inorganic salt usually the process of from polymeric foam just, removing remaining water finish the aftertreatment foam or with the processing of described salts solution as a part of from polymeric foam just, removing remaining water process.But with these aqueous solution handle foam preferably in foam the residual volume of deposition hydrated inorganic salt such as calcium chloride be at least 0.1% of foam wt, usually in 0.1 to 12% scope.

These hydrophobic relatively foams generally all proceed to the hydrophilic surfactant active's salt of hydration (but contain or do not contain) processing and must make foam have suitable hydrophilic degree.But the foam of preferred HIPE type is existing suitable wetting ability when being prepared into, but and may mix the salt hydrate of capacity, but therefore do not require and handle in addition with hydrophilic surfactant active or salt hydrate.Especially, these preferred hipe foams comprise the foam that those wherein use aforementioned some oil phase emulsifier and calcium chloride.In this case, the internal surface of polymeric foam has suitable wetting ability, and comprises the residual water liquid that contains or deposit the calcium chloride of capacity, even after foam of polymers has been dewatered to practical degree.

B. obtain the processing condition of hipe foam

The foamy preparation generally comprises following steps: the emulsion (HIPE) that 1) generates stable high interior phase; 2) generate under the condition of solid foam structure being suitable for, make this stable letex polymerization/curing; 3) this solid polymerization foamy structure of optionally washing, from the polymeric foam structure, to remove original residual water and if desired, but handle polymer foam structure with hydrophilic surfactant active and/or salt hydrate, but with the hydrophilic surfactant active/salt hydrate and 4 that deposits any needs) this polymer foam structure is dewatered.

1) formation of HIPR

By will oil phase and water component being mixed generation HIPE emulsion by aforesaid weight ratio.Oil phase contains necessary monomer, comonomer, linking agent and emulsifying agent usually, and optional components such as softening agent, antioxidant, fire retardant and chain-transfer agent.Water contains ionogen and polymerization starter usually, and optional component such as water soluble emulsifier.

The HIPE emulsion can generate from oil phase and the water that merges by shear agitation is carried out in these combinations mutually.Shear agitation generally proceeds to necessary degree of stable emulsion and the time of generating.This process may be carried out batchwise, perhaps carry out continuously, and generally be under the suitable condition that generates a kind of emulsion (wherein water dispense small droplets to so that the foam of polymers that generates has the degree of desired abscess-size and other structural performance), to carry out.Suitable mixing or whipping appts are the devices that can form emulsion under low shear-mixed.The emulsification of oil and aqueous phase composition usually comprises using and mixes or whipping appts such as pin type stirrer.

A kind of preferred method that generates this HIPE emulsion comprises mixes and a kind of successive processes of emulsive desired oil and water.In this course, form the liquid flow that comprises oil phase.Simultaneously, also generate the liquid flow that comprises water.In suitable mixing section or district, the water of these two kinds of liquid streams by aforementioned requirement is mixed with the oil phase weight ratio.

In mixing section or district, the liquid that combines stream generally all stands, for example the low shear agitation that is provided by the pin type stirrer of suitable configuration and size.Shear usually with 4000 seconds ^-1Or lower speed, preferred 3000 seconds ^-1Or lower speed is applied to blended oil/water liquid stream.In case form, stable liquid HIPE just can take out from mixing section or district.This preferably has more detailed description by the method for successive processes formation HIPEs herein in US5149720 (Thomas A.DesMarais, on September 22nd, 1992 authorized, and was incorporated herein by reference).Also can be referring to common unsettled U. S. application, sequence number (SN) 08/370694 (January 10 nineteen ninety-five, Thomas A.DesMarais submitted to, and numbering 5543 is incorporated herein by reference herein), this article has been described an improved successive processes with a HIPE circulation loop.

A special advantage using denseer emulsifier system among the HIPEs be HIPE form and casting cycle in mixing condition can be at about 50 ℃ or higher, finish under preferred 60 ℃ or the higher higher temperature.Usually, HIPE can form under about 60 to 99 ℃ temperature, and temperature more commonly used is 65 to 95 ℃.

2.HIPE polymerizable/curable

Normally the HIPE emulsion that generates is collected or poured suitable reaction unit, container or a place into and carry out polymerization or curing.In one embodiment, reaction unit comprises the groove of a polyethylene system, and the solid foam material of last polymerizable/curable can easily shift out (after polymerizable/curable reaches institute and requires degree) from this groove, further to process.Temperature and polymerizable/curable temperature that usually preferred HIPE emulsion is poured container into are roughly the same.

The condition of suitable polymerizable/curable can change, and this depends on the type and the consumption of the oil phase of monomer and emulsion and other component of aqueous phase (especially employed emulsifier system) and used polymerization initiator system.But usually suitable polymerizable/curable condition comprises and the HIPE emulsion is maintained about more than 50 ℃ that more preferably from about more than 65 ℃, most preferably at the comparatively high temps more than 80 ℃, the time kept about 2 to about 64 hours, more preferably from about 2 to about 48 hours.An advantage using more active emulsifier system is that cohesion has been reduced to minimum level when polymerizable/curable under comparatively high temps.HIPE also can be cured at the several stages described in US5189070 (Brownscombe etc., on February 23rd, 1993 authorized, and was incorporated herein by reference) herein.

Porous water-filling perforate hipe foam normally carries out obtaining behind the polymerizable/curable in reactor such as groove.This polymeric hipe foam imaging lamella shape that is cut into usually or cuts into slices.Polymeric hipe foam sheet is easier to operation during subsequently processing/washing and dehydrating step, and is easier to be formed in the hipe foam that uses in the absorbent article.The polymeric hipe foam is cut into usually/cuts into slices into about 0.08 to about 2.5cm slice thickness so that use to be provided.

3. processing/washing hipe foam

The residual aqueous phase substance that the hipe foam of the solid polymerization of making is used to prepare the HIPE emulsion usually is full of.These residual aqueous phase substance (generally being the aqueous solution of aqueous electrolyte liquid, residual emulsifying agent and polymerization starter) before foam is further processed and used, should partly be removed at least.This original removing normally of aqueous phase substance carried out to extrude residual liquid and/or water or other aqueous cleaning solution cleaning foamy structure the foamy structure pressurization.Usually with several pressurizations and washing step, for example use 2-4 circulation.

Original aqueous phase substance from foamy structure, remove reach desired degree after, if desired, can handle hipe foam, but for example with the suitable hydrophilic surfactant active and/or the salt continuous washing of hydration.But available hydrophilic surfactant active and salt hydrate were described in front.As previously mentioned, if necessary, but but carry out continuously till the hydrophilic surfactant active/salt hydrate that has mixed desired amount and foamy structure demonstrate desired adhesive tension to selected any test(ing) liquid with hydrophilic surfactant active/salt hydrate solution-treated hipe foam structure.

For some absorption agent purposes, wish from foam, to remove most residual electrolyte (that is, but salt hydrate).For example, if foam is that the removal of these salt is considerable in the time of will being used in the absorbent core (as hereinafter described) that also contains the fluid storage parts that absorb gelatinous material.In this case, but that the content of these salt hydrates in the foam drops in washing step is low as far as possible, drops to 2% or lower usually, preferably drops to 0.5% or lower.After removing these salt, hipe foam need carry out with the suitable hydrophilic surfactant active of significant quantity usually with hydrophilicity-imparting treatment again.

4. foam dehydration

After hipe foam being handled/washed, to dewater to it usually.Processed can be undertaken by following mode, promptly by crushed foam (preferably along Z to) to extrude residual water, by making foam and water wherein stand about 60 to about 200 ℃ temperature, or microwave treatment, carry out by vacuum hydro-extraction or by the combination of pressurization and heat drying/microwave/vacuum dehydration technology.Dehydrating step proceeds to hipe foam usually can use and be dried to practical degree.Usually the foamy moisture (wet) of these pressurizing and dehydratings amount is about 50 to about 500%, more preferably about 50 to about 200% (in dry weight).Subsequently, but the foam heat drying of pressurization is about 5 to about 40%, more preferably about 5 to about 15% (in dry weight) up to moisture content.

III. the purposes of foam of polymers

A. general introduction

Foam of polymers of the present invention is at disposable diaper, and purposes is widely arranged in the absorbent core of other absorbent article.These foams also can be used as environment waste oil absorption agent; Absorption piece as bandage or wrapper material; With applying coating on the dealing different surfaces; Be used in the Dust-removing mop head; Be used in the wet mop head; Be used in the fluid distributor; Be used in the wrapping material; Be used in the footwear as inhaling smelly (wetting) agent; Be used in the seat cushion; Be used in gloves other many aspects that neutralize.

B. absorbent article

Absorbing foams of the present invention can be used as the part of absorbing structure (as absorbent core) at least in various absorbent article." absorbent article " is meant a kind of consumer's goods herein, and it can absorb a large amount of urine or other fluid, resembles incontinence user or the moisture movement of goods user excretory (mobile intestines movement).The example of these absorbent articles comprises clothes, sanpro such as the tampon of disposable diaper, gatism and sanitary towel, disposable training pants, mattress etc.This absorbing foams structure is suitable in the goods such as protective layer as diaper, sanitary towel, tampon, gatism pad or clothes, clothes especially.

Because it is good attractive in appearance that its softness, resilient structures and physical integrity, absorbing foams of the present invention provide.Flaky these absorbing foams also are easy to be shaped to be used for multiple absorbent article relatively.Compare with the fibering absorption piece, these absorbing foams in use keep its overall appearance and structure basically, and are constant as density, shape, thickness etc.Because these absorbing foams can be by aqueous fluid plasticising, their mechanical property is constant substantially in dampness.

Because foam of the present invention absorbs and distributes aqueous fluid, they are particularly useful as the absorption of fluids/distribution member in the absorbent core.These absorption/dispense foam combine high relatively capillary absorption pressure and allow the unit weight absorptive capacity performance of its absorption fluids (no matter whether the help of gravity is arranged), have therefore kept user's xerosis cutis.This high absorptive capacity (given unit weight) can cause in light weight, effective product.

In addition, because absorbing foams of the present invention can be given other absorption piece with the release of fluid that absorbs effectively, also contain fluid storage/reallocation parts of being placed on lower floor " in " multilayer " absorbent core (absorbent core is placed between top flat and the egative film to form absorbent article), these foamy structures are useful especially as the absorption and distribution parts on upper strata.With regard to purpose of the present invention, the multilayer absorbent core " on " layer is meant relatively the one deck near user's health, for example by that nearest one deck of articles for use top flat.Term D score layer is then opposite, be meant relative to user's health one deck far away, for example by that nearest one deck of articles for use egative film.This lower floor's fluid storage/redistribution layer be placed on usually in the absorbent core with place under (upper strata) absorption of fluids/Distribution Layer and with its fluid communication.This lower floor's storage/redistribution layer can comprise many fluid storage/reallocation parts, comprise that those contain the parts that absorb gelatinous material, as disclosed parts in the following patent: US5061259 (Goldman etc., on October 29th, 1991 authorized), US4654039 (Brandt etc., on March 31st, 1987 authorized, on April 19th, 1988 authorized again, Re.32649), US4666983 (Tsubakimoto etc., on May 19th, 1987 authorized) and US4625001 (Tsubakimoto etc., on November 25th, 1986 authorized), all these patents all are incorporated herein by reference; Absorb the absorption agent macrostructure that gelatinous materials are made by these, as in the following patent disclosed those: US5102597 (Roe etc., on April 7th, 1992 authorized), US5324561 (Rezai etc., on June 23rd, 1994 authorized) all is incorporated herein by reference herein; Be laminated to the absorption gelatinous material between two tissue layer, as in the following patent disclosed those: US4260433 (Lindsay etc., on April 7th, 1981 authorized), US4467012 (Pedersen etc., on August 21st, 1984 authorized), US4715918 (Lang, on December 29th, 1987 authorized), US4851069 (Packard etc., on July 25th, 1989 authorized), US4950264 (Osbom, authorize August 21 nineteen ninety), US4994037 (Bemardin, on February 19th, 1991 authorized), US5009650 (Bernardin, on April 23rd, 1991 authorized), US5009653 (Osbom, on April 23rd, 1991 authorized), US5128082 (Makoui, on July 7th, 1992 authorized), US5149335 (Kellenberger etc., on September 22nd, 1992 authorized), US5176668 (Bernardin, on January 5th, 1993 authorized), all these all are incorporated herein by reference; With can store the fluidic absorbing foams that is absorbed, as disclosed in the following patent: US5268224 (DesMarais etc., on December 7th, 1993 authorized); Common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, be incorporated herein by reference herein) and common unsettled U. S. application, sequence number (SN) 08/370922 (Thomas A.Desmarais etc., submit to January 10 nineteen ninety-five, numbering 5541), all these all are incorporated herein by reference.

As for the relation of the position between absorption of fluids/dispense foam parts and fluid storage/reallocation parts in these multilayer absorbent core, not special restriction is as long as these parts can carry out fluid communication each other effectively and as long as each parts has enough greatly to keep effectively and/or to shift the aqueous body fluids that expectation will be discharged into the volume so of going in the absorbent article.The most preferred relation of absorption of fluids in the absorbent core/dispense foam parts and fluid storage/reallocation parts is that these parts are placed by the stratiform configuration.In such stratiform configuration, absorption of fluids/dispense foam parts comprise foam layer on, and foam layer is placed on the fluid storage/reallocation parts of an adjacent lower floor on this.It should be understood that this layer of two types only refers to upper area and the lower region in the absorbent core, might not be limited to individual layer or monolithic.Absorption of fluids/distribution zone, as the upper strata, and fluid storage/reallocation district can comprise the material of which floor required type as lower floor.Therefore, as used herein, term " layer " (layer) comprise " multilayer " (layers) and " stratiform " (layered).

Absorbent article generally includes the impermeable egative film of a fluid, the permeable top flat of a fluid (link together or otherwise link to each other) with egative film with egative film, and one be placed between egative film and the top flat according to absorbent core of the present invention.Top flat is placed on that side of the close body surface of absorbent core.Top flat preferably adopts method of attachment well known in the art and egative film to link together.As used herein, term " connects (joined) " and comprises by parts directly being fixed on the configuration that mode is direct with parts and other parts are fixed together on another parts, with by parts are fixed on one or several intermediate member, this intermediate member is fixed on the configuration that the mode on another parts is fixed together parts with other parts indirectly again.In preferred absorbent article, egative film and top flat directly couple together mutually along its periphery.

Egative film normally body fluid is impermeable, is therefore preferably made by thin plastic, though also can use other flexible fluid impermeable material.As used herein, term " flexible " be meant that material is submissive, thereby be easy to be consistent with the general shape and the profile of human body.The body fluid that egative film prevents from the absorbent core to absorb and preserves is got wet and the contacted clothes of absorbent article such as trousers, nightwear, underwear etc.Egative film can comprise weaving or non-woven material, polymeric film such as polyethylene or polyacrylic thermoplastic film, or matrix material is as the non-woven material of filming.Egative film preferably thickness is the polyethylene film of about 0.012mn (0.5mil) to about 0.051mm (2.0mils).The example of polyethylene film comprises Cincinnati, the name that the Clopay Corporation of Ohio produces is called the polyethylene film of P18-0401 and the Ethyl Corporation of Terre HauteIndiana, and the name that Visqueen Division produces is called the polyethylene film of XP-39385.Preferably egative film being carried out embossing and/or delustring handles so that its outward appearance more resembles fabric.In addition, egative film can allow steam to overflow from absorbent core (being breathable) but prevent that also body fluid flow from crossing egative film.

Top flat is submissive, feels softish and non-stimulated to user's skin.In addition, top flat is a fluid penetrable, allows body fluid to be easy to see through its thickness.Suitable top flat can be made by the material of broad range, as weaving and non-woven material; Polymer materials such as the porous thermoplastic film that is shaped; Porous plastic films and hydroforming thermoplastic film; Porous foam; Netted bubble end; The weblike heat plastic films; With thermoplasticity gauze (scrim).Suitable weaving and non-woven material can by natural fiber (as, xylon or cotton fibre), the mixed fibre of synthon (as polymer fiber such as polyester, polypropylene or polyethylene fibre) or natural fiber and synthon is formed.

Be used for the preferred top flat of the present invention and be selected from snappiness nonwoven top flat and porous formed film top flat.Porous formed film is to be preferably used as top flat especially, because they are permeable to bodily exudate and are non-absorbent and permission fluid with minimizing sees through and the tendency of rewetting user skin.Therefore, keep dry, reduced therefore that health pollutes and created a kind of more comfortable sensation for the user with the surface of the contacted formed film of health.The synthetic formed film has description: US3929135 (Thompson, on December 30th, 1975 authorized) in following patent; US4324246 (Mullane etc., authorize April 13 nineteen eighty-two); US4342314 (Radel etc., authorize August 3 nineteen eighty-two); US4463045 (Ahr etc., on July 31st, 1984 authorized); And US5006394 (Baird, on April 9th, 1991 authorized), all these all are incorporated herein by reference.Suitable micropore formed film top flat has description at US4609518 (Curro etc., on September 2nd, 1986 authorized) among the US4629643 (Curro etc., on December 16th, 1986 authorized), is incorporated herein by reference herein.

Formed film top flat health face can be hydrophilic to help body fluid to shift top flat (is not hydrophilic comparing with the health face) quickly to reduce fluid and flow out top flat rather than to flow to and be absorbed the possibility of going in the absorbing structure into.In a preferred embodiment, tensio-active agent is mixed in the polymer materials of formed film top flat, as common unsettled U. S. application, sequence number (SN) 07/794745 (" having the tectal absorbent article of a nonwoven and porous-film ", submissions such as Aziz on November 19 in 1991 are incorporated herein by reference herein) described in like that.In addition, the close body side surface of top flat can make its possess hydrophilic property by handling with tensio-active agent (described in above referenced US4950254, being incorporated herein by reference) herein.

In several embodiments according to the present invention, the absorption/Distribution Layer of absorbent core be placed on top flat and absorbent core in the position of storage/redistribution layer with certain positional relationship.More specifically, the absorption/Distribution Layer of absorbent core is placed on and makes its body fluid that can absorb discharging effectively and these body fluid are transferred to other regional position in the absorbent core.Therefore absorption/Distribution Layer can surround the near zone of body fluid discharge point.The zone (goods that the preferred male sex uses) that these zones comprise the crotch district and urinate previously at diaper.For diaper, the front of absorbent article means the part that will be placed on the user front of absorbent article.In addition, for male sex user, wish that absorption/Distribution Layer extends near user's front waist with fluid (betiding men's diaper front) that absorbs relative volume effectively and the variation that remedies emission direction.Corresponding absorbent article zone can change according to the design of absorbent article and configuration.

Can be placed on and top layer that extends and/or the relevant position of storage/redistribution layer the manufacturing of diaper, the absorption/Distribution Layer of absorbent core, thereby absorption/Distribution Layer have enough length with extend to top layer length at least about 50%, preferred 75% zone or extends to and stores/about 50% to about 120% corresponding zone of redistribution layer.Absorption/dispense foam layer should be enough wide to absorb the body fluid that sprays and to prevent that fluid directly is discharged on storage/redistribution layer.Usually, for diaper, the width of absorption/Distribution Layer should be at least about 5cm, preferably at least about 6cm.

In order to determine the position of this absorption/dispense foam layer, the length of absorbent article should be regarded the longest longitudinal size of routine of the article chassis of elongation as.This conventional longest dimension of the egative film of elongation defines according to goods after goods are used for the user.During use, the opposite end of egative film is fixed together, the end of Lian Jieing forms a circle around user's waist like this.The conventional length of the egative film point on the backsheet edge in the middle of a) user's low back of flowing through exactly on the egative film like this, through the crotch district to b) locate the line length of the point on the relative edge of egative film in the middle of the user Attacking Midfielder.The shape and size of top flat are corresponding basically with egative film usually.

Under normal conditions, limit the storage/redistribution layer of absorbent core of conventional length of article topsheet of the shape of absorbent article and elongation usually near the longest longitudinal size of storage/redistribution layer in the absorbent core.Yet in some goods (as adult incontinence product), it is very important to reduce volume or least cost, and the position of storage/redistribution layer only covers user's genital region and usually near the reasonable zone of genital region.In this case, absorption of fluids/Distribution Layer and storage/redistribution layer all are placed on the front portion of goods, and as top flat limits, thereby absorption/Distribution Layer and storage/redistribution layer are found preceding 2/3 place in goods length usually.

Absorption/dispense foam layer can be and aforementioned comfortable configuration and the corresponding to any desirable shape of limitation of size.These shapes comprise, and are for example circular, square, trapezoidal or oval, leak shape, splayed, half splayed, ellipse or irregularly shaped as water.Absorption/dispense foam layer can be the shape similar or different with storage/redistribution layer.Storage/the redistribution layer of preferred absorbent cores configuration also can be and the corresponding to any desirable shape of comfortable configuration, comprises for example circularly, square, trapezoidal or oval, leaks shape, splayed, half splayed, ellipse or irregularly shaped as water.Storage/redistribution layer need not separate with absorption/Distribution Layer or not contact fully with storage/redistribution layer.

Fig. 6 and 7 is depicted as a multilayer absorbent core configuration, and its fluid storage/reallocation parts comprise one and are generally rectangular top layer 64 (water that is placed under it leaks on shape absorption of fluids/distribution lower floor foam layer 65).Fluid storage/redistribution layer comprises an absorption of fluids hole 66, and body fluid is by this hole absorption/distribution lower floor 65 of discharging to contact its lower floor.

Figure 8 shows that disposable diaper with another kind of multilayer absorbent core configuration.This diaper comprises the impermeable egative film 71 of a top flat 70, one fluids, and a double-deck absorbent core that is placed between top flat and the egative film.Double-deck absorbent core comprise an improved water leak shape fluid storage/redistribution layer 72 be placed on improve water leak shape absorption of fluids/dispense foam layer 73 below.Top flat comprises the two substantially parallel obstruct leg cover bars 74 that elastic tape is arranged.Be fixed on the diaper chassis two ends is two rectangle elastic waist belt members 75.Also be fixed with two waist support parts 76 at the egative film two ends.Be fixed on the two parallel thigh elastic strips 77 that also have on the egative film.Sheet 78 is fixed on the egative film outside as being used for making the dedicated fixed surface of diaper around user's fixed two Y-type pieces 79.

The multilayer absorbent core also can be according to common unsettled U. S. application, sequence number (SN) 08/370900 (Gary DeanLaVon etc., submit to January 10 nineteen ninety-five, numbering 5547, be incorporated herein by reference herein) the method manufacturing, wherein one or more layers comprises one according to absorbing foams of the present invention.

V. testing method

A. capillary absorption pressure

Capillary absorbs isothermal curve and is to use common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc., submitted on December 11st, 1992, be incorporated herein by reference herein) the described vertical wicking of the Test Methods section amount of accommodating test draw, just be at 31 ℃ rather than 37 ℃.Curve is with every section the absorptive capacity function construction as measure wicking height, make the millpond top to the distance of every section mid point as height h.The capillary absorption pressure is counted as half the foamy height that absorptive capacity is the free absorptive capacity of foamy.

B. the capillary desorb is pressed

It is the tolerance that foamy keeps fluidic ability (as the function of different statical heads) that the capillary desorb is pressed.Suitable size, for example 40cm length * 2.5cm wide * sample strip and test fluid flow (distilled water contains a spot of food dye alternatively as indicator) that 0.2cm is thick all reach balance at 22 ± 2 ℃.Measurement is to carry out under this same temperature.

Foam strip is saturated in water, vertically places then, makes the low side 1-2mm in the pond that submerges.Allow water from sample, discharge up to reaching balance normally 16-24 hour.In this process, sample and pond all should cover, for example with glass infuser or aluminium foil, to prevent owing to evaporation causes water loss.Then sample is shifted out and is placed on the section that is cut into 2.5cm on the nonabsorbable surface rapidly, the part in the pond of wherein submerging is thrown away need not.With every section samples weighing, wash with water, dry and then weigh.Calculate the absorptive capacity of every section sample.

Capillary desorb isothermal curve is that the absorptive capacity by every section sample produces as the function construction of height.Curve is the graph of a relation of the absorptive capacity of every section sample as the function of the height of the test fluid flow of institute's desorb, and the millpond top is to the distance conduct height h of every section mid point.The capillary desorb is pressed and to be counted as half the foamy height that absorptive capacity is the free absorptive capacity of foamy.

C. anti-pressurization flexibility (RTCD)

Anti-pressurization flexibility can be measured with the deflection (% that thickness reduces) that the saturated back of synthetic urine produces by measuring foam sample, and this is to be subjected to measuring behind the qualification pressure of 0.74psi (5.1kPa) at foam sample.The measurement of anti-pressurization flexibility is normally carried out on same sample simultaneously with the following free absorptive capacity of measurement.

The synthetic urine of used Jayco is by with 2.0KCl in this method, 2.0gNa ₂SO ₄, 0.85gNH ₄H ₂PO ₄, 0.15g (NH ₄) ₂HPO ₄, 0.19gCaCl ₂And 0.23gMgCl ₂Mixture is dissolved in to be made in 1.0 liters of distilled water.This salt mixture can be from Endovations, Reading, and Pa (classification number JA-00131-000-01) has bought.

The foam sample that is used for measuring, the synthetic urine of Jayco and equipment are all crossed at 31 ℃ of constant temperature.All measurements are also all carried out under this temperature.

The foam sample sheet is immersed in the synthetic urine of Jayco is saturated to its free absorptive capacity.After 3 minutes, going out circular surface long-pending with sharp circular punch die on saturated sheet is 1 inch ²(6.5cm ²) cylinder.Cylindrical sample was soaked 6 minutes in 31 ℃ of synthetic urine again.Then sample is removed and is placed on from synthetic urine on the grouan platform that is suitable under the graduated scale of measure sample thickness.Setting graduated scale makes it apply the pressure of 0.08psi (0.6kPa) to sample.Any be furnished with that circular surface is long-pending to be at least 1 inch ²(6.5cm ²) footing and the measure thickness graduated scale that is of a size of 0.0001 inch (0.025cm) all can use.The example of these graduated scales have Ames type 482 (Ames Co., Waltham, MA) or Ono-sokki type EG-225 (Ono-Sokki Co., Ltd.; Japan).

After 2-3 minute, the thickness (X1) after record expands.Then a power is applied on the chi pin, so that the saturated foam sample stands the qualification pressure 15 minutes of a 0.74psi (5.1kPa).After current pressurization finishes, use graduated scale measure sample final thickness (X2).From initial and final thickness measurements, the deformation percentage ratio of inducing of sample can be obtained with following formula: [(X1-X2)/X1] * 100=thickness minimizing %.

D. reply (RFWC) from wet compression

The synthetic urine of foam sample, Jayco and measure equipment used and all be issued to balance 31 ℃ and 50% relative humidity.All measurements are all carried out under this temperature and humidity.Thickness is to measure with for example Ames type 482 or Ono-Sokki type EG-255 graduated scale under the pressure of about 0.08psi (0.55kPa).

Go out the foam cylindrical of thick 2mm, diameter 29mm on a foam piece.This cylinder is saturated to its free absorptive capacity in the synthetic urine of Jayco, is placed on then on No. 3 filter paper of Whatman level (particle keeps: 6 microns) of three diameter 9cm.The effect of filter paper is a high absorption pressure of simulating the reservoir part that is accompanied by absorbent article usually.

Foam/paper composites is compressed 75% wet foam thickness (the thick sample of 2mm is 1.5mm) with the area rigid plate bigger than foam sample immediately.Keep this strain 5 minutes, most of synthetic during this period urine separates from foam and enters in the filter paper.After 5 minutes, remove rigid plate, give the chance of foam to suck air and to be re-inflated from foam/paper composites.Remove limiting plate after 2 minutes, sample is separated with filter paper and measure its thickness.It is that sample is from the regressive measurement of wet compression that the regressive degree of thickness of sample (percentage ratio with initial thickness is represented) is taken as.Use the mean value of measuring at least 3 times to decide RFWC.

E. free absorptive capacity

Free absorptive capacity can be synthesized the amount of urinating the saturated synthetic urine that foam sample absorbed by measurement and come quantitatively.The measurement of free absorptive capacity is normally carried out on same sample simultaneously with the anti-pressurization of measurement flexibility.

Foam sample and synthetic urine reach balance at 31 ℃.Measurement is carried out at ambient temperature.

To be saturated to its free absorptive capacity in the synthetic urine of foam sample sheet immersion Jayco.3 minutes, going out circular surface long-pending from saturated expansion piece with sharp circular punch die was 1 inch ²(6.5cm ²) cylinder.Cylindrical sample was soaked 3 minutes in 31 ℃ of synthetic urine again.Then sample is removed and placed on the digital calculation balance from synthetic urine.Any be furnished with its area and be 1 milligram or littler day than the big pan of sample and sensitivity and on average can use.The example of these balances has Mettler PM480 and MettlerPC440 (Mettler Instruent Corp; Hightstown NJ).

After measuring the weight (Ww) of wet foam sample, foam sample is placed between 2 meticulous plastic mesh on 4 disposable tissues.Push sample 3 times by the screen cloth that a plastic roller is firmly rolled across the upper strata.Remove sample then, immersed in the distilled water about 2 minutes, be placed between screen cloth as previously mentioned then and push.Then sample is placed between 8 layers of disposable tissues (4 of every sides) and on Carver experimental pressure machine, applies 20000 pounds of pressure.Remove sample from paper handkerchief then, in baking oven,, write down its dry weight (Wd) 82 ℃ of dryings 20 minutes.

Free absorptive capacity (FAC) equals weight in wet base (Ww) and deducts dry weight (Wd) divided by dry weight (Wd), i.e. FAC=[(Ww-Wd)/Wd].

F kinetics mechanical analysis (DMA)

DMA is used for measuring polymkeric substance, comprises the Tg's of foam of polymers.Foam sample is cut into the thick piece of 3-5mm and washs 3-4 time in distilled water, clamps the fluid of squeezing out with roller between each washing.Allow the gained foam block at air drying.With the cylinder of dried foam sheet coring with generation diameter 25mm.Analyze these cylinders with Rheometrics RSA-II dynamic mechanical analysis instrument (be arranged on compressed state, use the parallel plate of diameter) as 25mm.Used instrument parameter is as follows:

The temperature rank from about 85 ℃ to-40 ℃, 2.5 ℃ on every rank;

Immersion interval 125-160 second between the temperature variation;

Dynamic strain is set in 0.1-1.0% (being generally 0.7%);

Frequency setting is at 1.0 radian per seconds;

Automatic stress is set in static(al) and follows the tracks of dynamic mode, and initial static(al) is set in 5g;

Second-order transition temperature is considered to the vertex of loss tangent-temperature curve.

G. interfacial tension (IFT) method (spinning solution drips)

Interfacial tension (IFT) is by common unsettled U. S. application, sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to, be incorporated herein by reference herein) described in method measure with the spinning solution method of dripping at 50 ℃, just (1) is used for preparing the used monomer mixture of oil phase to comprise weight ratio is 14: 14: 60: 12 vinylbenzene, Vinylstyrene (55% technical grade), 2-EHA and dimethacrylate 1,4-butanediol ester; (2) concentration of emulsifying agent is reduced to IFT by dilution from the upper limit concentration of common about 5-10% weight and is increased to the concentration of its value than minimum IFT about 10 dynes per centimeter of height or about 18 dynes per centimeter in the oil phase, and no matter which is lower; (3) fair line that the log emulsifier concentration is marked with IFT decides minimum IFT; (4) critical cohesion concentration (CAC) is by the extrapolation lower concentration, normally IFT to the linear portion of log concentration curve (promptly, be commonly used to calculate the curved portion of the surface-area of per molecule at the interface, referring to for example Surfactants and Interfacial Phenomena (tensio-active agent and surface phenomenon), second edition, Milton J.Rosen, 1989, the 64-69 pages or leaves) partly decide to higher concentration; Being taken as with the corresponding emulsifier concentration of minimum IFT on this extrapolation line is CAC.Usually, use the emulsifier concentration upper limit of about 5-10% weight.Wish to be limited on the used emulsifier concentration emulsifying agent CAC at least about twice (more hope) at least about 3 times.For under the room temperature in the solubleness in the oil phase less than for the emulsifying agent of 5% weight, can reduce the restriction of upper limit of concentration, as long as this concentration under 50 ℃, remain emulsifying agent CAC at least about twice.

VI. specific embodiment

These embodiment have illustrated the concrete preparation according to closely knit hipe foam of the present invention.

A) preparation of HIPE

Anhydrous lime carbonate (36.32kg) and Potassium Persulphate (567g) are dissolved in 378 premium on currency.This provides employed water liquid stream for the successive processes that generates the HIPE emulsion.

To comprising 1600g vinylbenzene, add highly purified single oleic acid double glyceride of 480g and Tinuvin765 (two (1,2,2 in the monomer mixture of 1600g Vinylstyrene (55% technical grade) and 4800g 2-EHA, 5,5-pentamethyl-piperidyl) sebate) antioxidant (40g).

This single oleic acid double glyceride emulsifying agent is by common unsettled U. S. application, the general method preparation of the preparation polyglycerol esters described in the sequence number (SN) 989270 (Dyer etc., on December 11st, 1992 submitted to).Comprise about 97% or more Glycerol dimer and 3% or (the SolvayPerformance Chemicals of triglycerin still less; Greenwich, poly-glycerine composition Conn) with fatty acid composition (this fatty acid composition comprises about 71%C18: 1,4%C18: 2,9%C16: 1,5%C16: 0 and 11% other lipid acid (Emersol-223LL; Emery/Henkel)) with 60: 40 weight ratio emulsification, with sodium hydroxide as catalyzer in 255 ℃ of mechanical stirring, spray nitrogen, and increase vacuum tightness gradually, with the phosphoric acid neutralization, be cooled to 85 ℃ then, precipitation is to reduce the content of unreacted poly-glycerine.The cut of diglycerol monoester to reduce the content of unreacted poly-glycerine and lipid acid, is rich in the fractionation of two placed in-line CMS-15A centrifugal molecular stills then in polyglycerol esters reaction product elder generation with generation with the distiller redistillation.The typical conditions of last still-process is 15 Pounds Per Hours for defeated material speed, and the degasser vacuum is the 21-26 micron, and pin cover vacuum is the 6-12 micron, and defeated material temperature is 170 ℃, and the resistates temperature is 180 ℃.Mix the cut that is rich in diglycerol monoester, the reaction product of generation (identifying with supercritical fluid chromatography) comprises about 50% single oleic acid double glyceride, 27% other diglycerol monoester, 20% poly-glycerine and 3% other polyglycerol esters.It is about 1.0 dynes per centimeter that gained list oleic acid double glyceride emulsifying agent makes the interfacial tension value of minimum oil phase/water, and to have critical cohesion concentration be about 0.9% weight.After the mixing, allow the reaction product sedimentation spend the night.Take out the emulsifying agent of supernatant liquid as the oil phase that generates HIPE.(about 20g thickness resistates is thrown away.)

Oil phase (25 ℃) and water (70-74 ℃) two independent liquid streams are sent in the dynamic mixers.Make combined stream in dynamic mixer, realize thoroughly mixing with the pin type homogenizer.When this working scale, a kind of suitable pin type homogenizer comprises that one is about the cylindrical shaft of the about 1.9cm of 21.6cm diameter.4 row's pins are arranged on the axle, and two rows have 17 pins, and two rows have 16 pins, and every diameter is about 0.5cm, and protruding 1.6cm is long from the central shaft of axle.The pin type homogenizer is installed in and forms the dynamic agitation device on the cylindrical sleeve, and the gap of 0.8mm is arranged between pin and the cylindrical sleeve barrel.

The downstream that one volution static mixer is installed in dynamic mixer thinks that dynamic mixer provides back pressure and the mixing of each component in the emulsion of final formation of improvement is provided.Long 14 inches (35.6cm) of this static mixer, 0.5 inch of external diameter (1.3cm).Static mixer is the industrial 070-821 of TAH, changes system into after cutting away 2.4 inches (6.1cm).

In the associating mixing device by the ratio of 1 part of oil of 2 parts of water pack into oil phase and water.Dynamic mixer ventilates with exhausted air when filling device.Flow rate between charging period is 3.78 Grams Per Second oil phases and 7.56 Grams Per Second waters.

In case fill device, dynamic mixer just begins to stir, the agitator slewing rate be 1200RPM (rev/min).The water flow rate stably was increased to 44.1 milliliters/second in 30 seconds then, and the oil phase flow rate reduced to 1.25 Grams Per Seconds in 1 minute.Back pressure dynamic and that static mixer produces is 5.0psi (35kPa) at this moment.Agitator speed steadily dropped to the speed of 600RPM in 120 second time then.System back pressure is reduced to 1.8PSI (12kPa) and keeps constant after this.The water-oil ratio of the HIPE of gained is about 36: 1.

B) polymerizable/curable of HIPE

Be collected in the circular polypropylene tank of diameter 17 inch (43cm) high 7.5 inch (10cms) by the effusive HIPE of static mixer this moment, and the concentric lining of this polypropylene tank is that the Celcon plastics are made.5 inches of sleeve diameters (12.7cm), 4.75 inches of top diameters (12cm), high 6.75 inches (17.14cm).The groove that HIPE is housed is kept in 65 ℃ the room 18 hours to solidify and to generate the polymerization hipe foam.

C) foamy washing and dehydration

From groove, take out the solidified hipe foam.The foam of this moment contains the residual water of about 32-38 times (32-38X) of polymerization single polymerization monomer weight, and wherein this water contains dissolved emulsifying agent, ionogen, initiator residues and initiator.Foam is cut into slices with sharp reciprocating type saw blade, and the thickness of sheet is 0.075 inch (0.19cm).Then these sheets are compressed between placed in-line 2 the porous nip rollss that vacuum is housed, residual water phase content in the foam is reduced to polymerization single polymerization monomer heavy 2 times (2X) gradually.At this moment, then with sheet with 0.75% CaCl ₂The aqueous solution is saturated again at 60 ℃; And between placed in-line 3 the porous nip rollss that vacuum is housed, be compressed to aqueous phase content and be about 4X.Foamy CaCl ₂Content is between 2 to 5%.

Foam is at air drying about 16 hours then.This drying is reduced to moisture content the 4-10% of polymeric material weight.

Embodiment 2: prepare foam by HIPE

A) preparation of HIPE

Anhydrous calcium chloride (36.32kg) and Potassium Persulphate (189g) are dissolved in 378 premium on currency.This provides employed water liquid stream for the successive processes that generates the HIPE emulsion.

To comprising 600g vinylbenzene, 700g Vinylstyrene (technical grade), 3100g 2-EHA and 600g dimethacrylate 1, add the single oleic acid double glyceride of 250g in the monomer mixture of 4-butanediol ester, 50g 2-octyl group dodecyl Glycerol dimer ether and 4lg Tinuvin765 antioxidant (30g).

Used identical of single oleic acid double glyceride emulsifying agent and embodiment 1.2-octyl group dodecyl Glycerol dimer ether co-emulsifier prepares as follows: adopt common unsettled U. S. application, (January 10 nineteen ninety-five is by submissions such as Stephen A.Goldman for sequence number (SN) 08/370920, the numbering 5540, be incorporated herein by reference herein) described in aliphatic glycidyl ether legal system be equipped with 2-octyl group dodecyl Glycerol dimer ether.About 360g Epicholorohydrin joins about 1.5kg 2-Standamul G (Jarcol I-20 of stirring; Jarchem Industries) and in the mixture of about 10g tin tetrachloride.When the reaction liberated heat is heated to about 70 ℃ with reaction mixture, under nitrogen protection in about 6 hours of about 65 ℃ of restir mixtures.Adding is diluted in the about 190g sodium hydroxide in about 28g distilled water in advance and reacted about 6 hours under about 65 ℃ then.After separating the waterbearing stratum, organic layer washes with water 3 times, is heated to about 95 ℃, spray nitrogen drying, and in about 185-210 ℃ scope＜distill to produce about 1.1kg 2-octyl group lauryl diglycidyl ether under the 1mmHg.About 8.lg sodium methylate (25% weight in the methyl alcohol) and about 1400g anhydrous glycerol reacted about 3 hours in about 130 ℃ under nitrogen.After reaction mixture is heated to about 185 ℃, in about 2 hours, drip 2-octyl group lauryl diglycidyl ether.Under nitrogen,, under agitation condition, do not allowing the mixture cooling then in about 4 hours of the about 185 ℃ mixtures that stir to generate.Remove the glycerin layer that is deposited in the bottom by siphon.From surplus materials, remove fugitive constituent by under about 2mmHg, being heated to about 150 ℃, produce about 1.3kg product.About 700g product is dissolved in the excessive mixing hexane.This hexane is used 90:10 mutually, and (volume: methyl alcohol volume): water extracts repeatedly.Mix methyl alcohol: water extract also removes with rotary evaporator and to desolvate.The gained resistates is heated to about 70 ℃ and also uses the glass microfiber filter paper filtering, produces about 380 gram 2-octyl group dodecyl Glycerol dimer ether emulsifying agents.Find that with the gel osmoticing chromatogram analysis product this product is about 82% Glycerol dimer list aliphatic ether and about 5% triglycerin, two aliphatic ethers.It is about 3.9 dynes per centimeter that this emulsifying agent makes minimum oil phase/aqueous phase interface tension value, and critical cohesion concentration is about 0.5% weight.

After the mixing, allow this mixture standing over night.Do not form the visible throw out, take out the oil phase that all mixtures are used to form the successive processes of HIPE emulsion.

In the water temperature is that 85-90 ℃ and oil phase temperature are under 23 ℃ the situation, and water and oil phase two independent liquid streams are sent in the dynamic mixers.Make combined stream in dynamic mixer, realize thoroughly mixing with the pin type homogenizer, in embodiment 1.In embodiment 1, the downstream that the volution static mixer also is installed in dynamic mixer thinks that dynamic mixer provides back pressure and the mixing of each component in the emulsion of final formation of improvement is provided.In the mixing device of combination by the ratio of 1 part of oil of 2 parts of water pack into oil phase and and water.Dynamic mixer ventilates with exhausted air when filling device.Flow rate between charging period is 3.78 Grams Per Second oil phases and 7.56 milliliters/second waters.

In case fill equipment configuration, the water flow rate reduces by 25% to reduce the pressure rising that causes because of stopping to ventilate.Dynamic mixer begins to stir then, and the agitator slewing rate is 1800RPM.The water flow rate steadily was increased to 37.8 milliliters/second in 1 minute then, and the oil phase flow rate reduced to 0.84 Grams Per Second in 2 minutes.When the water flow rate reached 37.8 milliliters/second, agitator speed was reduced to 1200RPM immediately, steadily was reduced to 900RPM then in 1 minute.This moment, back pressure dynamic and that static mixer produces was about 2.3PSI (16kPa).Agitator speed steadily was reduced to about 850RPM in 1 minute then.This moment, back pressure dynamic and that static mixer produces was about 2.2PSI (15kPa).The water-oil ratio of gained HIPE is about 45: 1.

B) polymerization of emulsion

Be collected in circular polypropylene tank, as in Example 1 by the effusive HIPE that forms of static mixer this moment.The groove that will contain emulsion be kept in 82 ℃ the room 4 hours so that emulsion in container polymerization to generate polymeric foam.

C) foamy washing and dehydration

After solidifying end, from solidify groove, take out the moisture curing foam.The foam of this moment contains the residual water of about 40-50 times (40-50X) of polymeric material weight, and wherein this water contains dissolved emulsifying agent, ionogen, initiator residues and initiator.Foam is cut into slices with sharp reciprocating type saw blade, and the thickness of sheet is 0.075 inch (0.19cm).Then these sheets are compressed between placed in-line 2 the porous nip rollss that vacuum is housed, remaining water content in the foam is reduced to about 3 times (3X) of polymeric material weight gradually.At this moment, with sheet with 1.5% CaCl ₂The aqueous solution 60 ℃ saturated again, and between placed in-line 3 the porous nip rollss that vacuum is housed, be compressed to aqueous phase content and be about 1X.Foamy CaCl ₂Content is between 2 to 5%.

Then with this foam about 16 hours at air drying.This drying is reduced to moisture content about 4-10% of polymeric material weight.

Embodiment 3. prepares foam from HIPE

A) preparation of HIPE

Anhydrous calcium chloride (36.32kg) and Potassium Persulphate (1.13kg) are dissolved in 378 premium on currency.This provides employed water liquid stream for the successive processes that generates the HIPE emulsion.

To comprising 1750g distillation Vinylstyrene (40% Vinylstyrene and 60% ethyl styrene), 2750g 2-EHA and 500g diacrylate 1, add the single oleic acid double glyceride of 250g in the monomer mixture of 4-hexylene glycol ester, 50g dihydro fat dimethyl sulfate ammonium methyl and 25gTinuvin765 antioxidant.This single oleic acid double glyceride emulsifying agent (Grindsted Products; Brabrand, Denmark) comprise other diglycerol monoester of about 82% single oleic acid double glyceride and 1%, 7% poly-glycerine and 11% other polyglycerol esters, it is about 2.4 dynes per centimeter that this emulsifying agent makes minimum oil phase/aqueous phase interface tension value, and critical cohesion concentration is about 3.0% weight.Dihydro fat dimethyl sulfate ammonium methyl obtains from Witco/sherex Chemical Co..It makes minimum oil phase/aqueous phase interface tension value is about 2.5 dynes per centimeter, and critical cohesion concentration is about 0.065% weight.After the mixing, allow this mixture standing over night.Only form a small amount of visible precipitate, take out the emulsifying agent of nearly all mixture as the oil phase in the successive processes that generates the HIPE emulsion.

In the water temperature is that 85 ℃-90 ℃ and oil phase temperature are under 20 ℃ the situation, and water and oil phase two independent liquid streams are sent in the dynamic mixers.Make combined stream in dynamic mixer, realize thoroughly mixing with the pin type homogenizer, in embodiment 1.In embodiment 1, the downstream that the volution static mixer also is installed in dynamic mixer thinks that dynamic mixer provides back pressure and the mixing of each component in the emulsion of final formation of improvement is provided.In the mixing device of combination by the ratio of 1 part of oil of 2 parts of water pack into oil phase and water.Dynamic mixer is ventilated with exhausted air when filling device.Flow rate between charging period is 3.78 Grams Per Second oil phases and 7.6 milliliters/second waters.

In case fill equipment configuration, the water flow rate reduces by 25% to reduce the pressure rising that causes because of stopping to ventilate.Dynamic mixer begins to stir then, and the agitator slewing rate is 1200RPM.The water flow rate steadily was increased to 37.8 milliliters/second in 1 minute then, and the oil phase flow rate reduced to 0.63 Grams Per Second in 3 minutes.This moment, back pressure dynamic and that static mixer produces was about 3PSI (21kPa).Agitator speed steadily was reduced to about 800RPM in 2 minutes then.Back pressure is reduced to about 2.3PSI (16kPa).The water-oil ratio of gained HIPE is about 60: 1.

B) polymerization of emulsion

Be collected in circular polypropylene tank, as in Example 1 by the effusive HIPE that forms of static mixer this moment.The groove that will contain emulsion is kept in 82 ℃ the room 2 hours so that thereby emulsion polymerization in container generates polymeric foam.

C) foamy washing and dehydration

After solidifying end, from solidify groove, take out the moisture curing foam.The foam of this moment contains the doubly residual water of (50-60X) of the about 50-60 of polymeric material weight, and wherein this water contains dissolved emulsifying agent, ionogen, initiator residues and initiator.Foam is cut into slices with sharp reciprocating type saw blade, and the thickness of sheet is 0.050 inch (0.127cm).Then these sheets are compressed between placed in-line 2 the porous nip rollss that vacuum is housed, remaining water content in the foam is reduced to about 3 times (3X) of polymeric material weight gradually.At this moment, then with sheet with 1.5% CaCl ₂The aqueous solution 60 ℃ saturated again, and between placed in-line 3 the porous nip rollss that vacuum is housed, be compressed to aqueous phase content and be about 1X.Foamy CaCl ₂Content is between 1 to 4%.

Then with this foam about 16 hours at air drying.This drying is reduced to moisture content about 3-12% of polymeric material weight.

Claims (16)

1. polymer foams that can absorb and distribute aqueous fluid, this polymer foams comprise a non-ionic polymer foam structure of hydrophilic softness with the open cells that is interconnected, and it is characterized in that this foamy structure has:

A) be less than for 120 seconds, preferably be less than and synthesize the urine vertical wicking in 70 seconds to the 5cm height

Ability;

B) the capillary absorption pressure is 5 to 25, and preferred 5 to 15cm;

C) capillary desorb pressure is 8 to 40, is preferably 8 to 25cm;

D) the compression deformation of measuring when limiting pressure for 5.1kpa is about 5 to about 85%, preferred 5

To 65%, most preferably be 5 to 50%; With

E) free absorptive capacity is 12 to 125, and is preferred 35 to 90, most preferably is 45 to 75g/g;

F) reply at least 60% from wet compression, preferably at least 75%.

2. foam materials as claimed in claim 1 is characterized in that this foamy number average cell size is 20 to 200 microns, and preferred 30 to 130 microns diameters with the number average perforate are 5 to 30 microns, preferred 8 to 25 microns.

3. as each described foam materials of claim 1 to 2, it is characterized in that the specific surface area that the every lather volume of described foamy structure has is 0.01 to 0.06, preferred 0.01 to 0.04 meter ²/ milliliter.

4. as each described foam materials of claim 1 to 3, it is characterized in that described foam is to be formed by polymeric water-in-oil emulsion, this emulsion has:

1) oil phase comprises:

A) about 85 to about 98% weight, and preferred 90 Tg that can form to about 97% weight are 35 ℃ or lower, the monomer component of preferred 15 to 30 ℃ multipolymer, and this monomer component comprises:

I) 30 to 80% weight a kind of water-fast basically can form the monofunctional monomer that Tg is about 25 ℃ or lower polymkeric substance;

The ii) a kind of water-fast basically simple function comonomer that the toughness toughness about equally that is provided with vinylbenzene can be provided of 5 to 40% weight;

The iii) water-fast basically first multifunctional linking agent of 5 to 25% weight, this linking agent is selected from the group of being made up of following material: Vinylstyrene, trivinylbenzene, divinyl toluene, divinyl dimethylbenzene, divinyl naphthalene, divinyl alkylbenzene, divinyl phenanthrene, divinyl biphenyl, divinyl ditan, divinyl benzyl, divinyl phenyl ether, divinyl diphenylsulfide, divinyl furans, vinyl thioether, divinylsulfone, and composition thereof; With

The iv) water-fast basically second multifunctional linking agent of 0 to 15% weight, this linking agent is selected from the group of being made up of following material: polyfunctional acrylic ester, methacrylic ester, acrylamide, Methacrylamide and composition thereof;

B) 2 to 15% weight, a kind of emulsifying agent component of preferred 3 to 10% weight, this emulsifying agent can be dissolved in oil phase and be applicable to and form stable water-in-oil emulsion; With

2) comprise 0.2 to 20% weight, a water-soluble ionogen of preferred 1 to 10% weight, a water of preferably calcium chloride;

3) envelope-bulk to weight ratio of water and oil phase is at 35: 1 to 90: 1, in preferred 45: 1 to 75: 1 scope.

5. foam materials as claimed in claim 4, wherein said monomer comprises:

I) 50 to 65% weight are selected from the monomer of the group of being made up of following material: vinylformic acid C ₄-C ₁₄Alkyl ester, aryl acrylate and alkane aromatic ester, the C of methacrylic acid ₆-C ₁₆Alkyl ester, C ₄-C ₁₂Ring-alkylated styrenes, acrylamide and composition thereof;

Ii) 15 to 25% weight are selected from the comonomer of the group of being made up of following material: vinylbenzene, ethyl styrene and composition thereof; With

The iii) Vinylstyrene of 12 to 20% weight; With

Iv) described second linking agent that is selected from the group that following material forms of 0 to 13% weight: dimethacrylate 1,4-butanediol ester, Ethylene glycol dimethacrylate, diacrylate 1,6-hexylene glycol ester and mixture.

6. foam materials as claimed in claim 5 is characterized in that described unibody piece of foam (i) is selected from the group of being made up of following material: butyl acrylate, Ethyl acrylate, Octyl acrylate, 2-EHA, vinylformic acid ester in the ninth of the ten Heavenly Stems, decyl acrylate, dodecylacrylate, isodecyl acrylate, vinylformic acid ester in four last of the ten Heavenly stems, benzyl acrylate, vinylformic acid nonyl phenyl ester, N-Hexyl methacrylate, Octyl methacrylate, nonyl methacrylate, decyl-octyl methacrylate, isodecyl methacrylate, lauryl methacrylate, methacrylic acid ester in four last of the ten Heavenly stems, right-n-octyl ethene, N-octadecyl acrylamide and composition thereof.

7. absorbent article that is particularly suitable for absorbing and keeping aqueous body fluids, described goods comprise:

I) egative film; With

II) absorbent core that links to each other with described egative film, described absorbent core place between user's the fluid discharge areas of described egative film and goods, and described absorbent core is characterised in that it comprises each foam materials of claim 1 to 6.

8. absorbent article as claimed in claim 7, it is characterized in that described absorbent core comprises: (1) one fluid processing layer, this layer comprise the foam materials that is placed in the described fluid discharge region; (2) one with the fluid storage/redistribution layer of described fluid treatment layer fluid communication.

9. diaper that is used to absorb the aqueous body fluids of incontinent person's discharging, described diaper goods comprise:

I) the impermeable relatively egative film of a fluid;

II) the permeable relatively top flat of a fluid;

III) absorbent core that is placed between described egative film and the described top flat, the feature of described absorbent core exists

Comprise each described foam materials of claim 1 to 6 in it.

10. one kind prepares the method that can absorb and distribute the suction polymeric foam materials of aqueous fluid, comprises the steps:

A), under preferred about 60 to about 99 ℃, under low shear agitation, form water-in-oil emulsion by following material at 50 ℃ or higher temperature:

1) oil phase comprises:

A) about 85 to about 98% weight, and the Tg that can form of preferred 90 to 97% weight is 35 ℃ or lower, the monomer component of preferred 15 to 30 ℃ multipolymer, and this monomer component comprises:

I) 30 to 80% weight are at least a water-fastly basically can form the monofunctional monomer that Tg is about 25 ℃ or lower random amorphous polymer;

Ii) the toughness that is provided with vinylbenzene flexible simple function comonomer about equally can be provided a kind of water-fast basically of 5 to 40% weight;

The iii) water-fast basically first multifunctional linking agent of 5 to 25% weight, this linking agent is selected from

The group that following material is formed: Vinylstyrene, trivinylbenzene, divinyl toluene, diethyl

Thiazolinyl dimethylbenzene, divinyl naphthalene, divinyl alkylbenzene, divinyl phenanthrene, divinyl

Biphenyl, divinyl ditan, divinyl benzyl, divinyl phenyl ether, divinyl

The base diphenylsulfide, the divinyl furans, vinyl thioether, divinylsulfone, and mix

Compound; With

The iv) water-fast basically second multifunctional linking agent of 0 to 15% weight, this linking agent is selected from the group of being made up of following material: polyfunctional acrylic ester, methacrylic ester, acrylamide, Methacrylamide and composition thereof; With

B) 2 to about 15% weight, one emulsifying agent component of preferred 3 to 10% weight, this emulsifying agent can be dissolved in oil phase and be suitable for use in and form stable water-in-oil emulsion, this water-in-oil emulsion comprises: (i) have first emulsifying agent of at least 40% weight emulsification component, this emulsifying agent component is selected from the group of being made up of following material: linear unsaturated C ₁₆-C ₂₂The diglycerol monoester of lipid acid, branching C ₁₆-C ₂₄The diglycerol monoester of lipid acid, branching C ₁₆-C ₂₄The Glycerol dimer list aliphatic ether of alcohol, linear unsaturated C ₁₆-C ₂₂The Glycerol dimer list aliphatic ether of Fatty Alcohol(C12-C14 and C12-C18), linear saturated C ₁₂-C ₁₄The Glycerol dimer list aliphatic ether of alcohol, linear unsaturated C ₁₆-C ₂₂The anhydro sorbitol monoesters of lipid acid, branching C ₁₆-C ₂₄The anhydro sorbitol monoesters of lipid acid, and composition thereof; Or (ii) have at least about one first emulsifying agent of the described emulsification component of 20% weight and the mixture of one second emulsifying agent, the weight ratio of first emulsifying agent and second emulsifying agent is 50: 1 to 1: 4, and described second emulsifying agent is selected from the group of being made up of following material: long-chain C ₁₂-C ₂₂Two aliphatic series, short chain C ₁-C ₄Two aliphatic quaternary ammonium salts, long-chain C ₁₂-C ₂₂Dialkoxy (alkenyloxy)-2-hydroxyethyl, short chain C ₁-C ₄Two aliphatic quaternary ammonium salts, long-chain C ₁₂-C ₂₂Two aliphatic imidazoline quaternary ammonium salts, short chain C ₁-C ₄Two aliphatic series, long-chain C ₁₂-C ₂₂Monoester family benzyl quaternary ammonium salt, and composition thereof.

2) water: comprise: (a) 0.2 to 20% weight, the water-soluble ionogen of preferred 1 to 10% weight one, preferably calcium chloride; (b) polymerization starter of a significant quantity;

3) weight ratio of water and oil phase is at 12: 1 to 125: 1, and preferred 35: 1 to 90: 1, most preferably in 45: 1 to 75: 1 the scope; With

B) in the oil phase of water-in-oil emulsion the polymerization single polymerization monomer component to form polymer foams.

11. method as claimed in claim 10 is characterized in that this method also comprises step B) the polymer foams dehydration degree that can absorb and distribute aqueous fluid up to the polymer foams that forms.

12. method as claimed in claim 11 is characterized in that described monomer component comprises:

I) 50 to 65% weight are selected from the monomer of the group of being made up of following material: vinylformic acid C ₄-C ₁₄The C of alkyl ester, aryl acrylate and alkane aromatic ester, methacrylic acid ₆-C ₁₆Alkyl ester, C ₄-C ₁₂Ring-alkylated styrenes, acrylamide and composition thereof;

Ii) 15 to 25% weight are selected from the comonomer of the group of being made up of following material: vinylbenzene, ethyl styrene and composition thereof; With

The iii) Vinylstyrene of 12 to 20% weight; With

Iv) described second linking agent that is selected from the group of forming by following material of 0 to 13% weight: dimethacrylate 1,4-butanediol ester, Ethylene glycol dimethacrylate, diacrylate 1,6-hexylene glycol ester and composition thereof.

13. method as claimed in claim 12, it is characterized in that monomer (i) is selected from the group of being made up of following material: butyl acrylate, Ethyl acrylate, Octyl acrylate, 2-EHA, vinylformic acid ester in the ninth of the ten Heavenly Stems, decyl acrylate, dodecylacrylate, isodecyl acrylate, vinylformic acid ester in four last of the ten Heavenly stems, benzyl acrylate, vinylformic acid nonyl phenyl ester, N-Hexyl methacrylate, Octyl methacrylate, nonyl methacrylate, decyl-octyl methacrylate, isodecyl methacrylate, lauryl methacrylate, methacrylic acid ester in four last of the ten Heavenly stems, right-n-octyl ethene and composition thereof.

14., it is characterized in that described first emulsifying agent comprises the emulsification component that at least 70% weight is selected from the group of being made up of following material: single oleic acid double glyceride, single Unimac 5680 double glyceride, single oleic acid Isosorbide Dinitrate and composition thereof as each described method of claim 10 to 13.

15. as each described method of claim 10 to 14; it is characterized in that described second emulsifying agent is selected from the group of being made up of following material: Quaternium 48; two three decyl alkyl dimethyl ammonium chlorides; two fat dimethyl sulfate ammonium methyls; two fatty acyl groups-2-hydroxyethyl dimethyl ammonium chloride; methyl isophthalic acid-acyl amino-ethyl-2-fat tetrahydroglyoxaline methyl sulfate, methyl isophthalic acid-oleoyl amido ethyl-2-oleoyl tetrahydroglyoxaline methyl sulfate, dimethyl stearyl benzyl ammonium chloride and composition thereof.

16. method as claimed in claim 15 is characterized in that described second emulsifying agent is selected from the group of being made up of following material: Quaternium 48 and two fat dimethyl sulfate ammonium methyls.

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