CN114410045B

CN114410045B - Method for preparing antibacterial foam absorbing material from HIPPE, foam absorbing material and application thereof

Info

Publication number: CN114410045B
Application number: CN202210038118.8A
Authority: CN
Inventors: 尉晓丽; 方璞; 潘世伟
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2022-03-09
Filing date: 2022-03-09
Publication date: 2023-09-19
Anticipated expiration: 2042-03-09
Also published as: CN114410045A

Abstract

The invention relates to a method for preparing an antibacterial foam absorbing material by HIPPE, the foam absorbing material and application thereof, and an open-cell antibacterial porous foam absorbing material is prepared by an ultra-high internal phase Pickering emulsion which is jointly stabilized by hydrophobically modified nano zinc oxide and cellulose nano particles. The preparation method provided by the invention has the advantages of low emulsifier consumption, high foam strength, good hydrophilicity and low reverse osmosis, can be used for absorbing aqueous fluid, and has a good antibacterial effect. When the antibacterial foam absorbent material is applied to disposable sanitary products, the antibacterial foam absorbent material can endow the sanitary products with good absorption performance and has excellent antibacterial effect.

Description

Method for preparing antibacterial foam absorbing material from HIPPE, foam absorbing material and application thereof

Technical Field

The invention relates to the technical field of preparation of porous foam materials, in particular to a preparation method of an antibacterial porous foam absorbing material obtained by solidifying ultra-high internal phase Pickering emulsion, a foam absorbing material and application thereof.

Background

The ultra-high internal phase Pickering emulsion is an ultra-concentrated emulsion system which is stabilized by adopting colloid particles to replace a traditional surfactant and has the volume fraction of a dispersed phase higher than 74%, and because solid particles have irreversible adsorption capacity on an interface, namely high desorption energy, the particles are difficult to desorb once adsorbed on a water-oil interface, so that coalescence among liquid drops is prevented, and good dynamic stability is provided for the dispersed phase. Compared with the traditional HIPE emulsion preparation, the Pickering HIPE emulsion (HIPPE) can obtain good emulsion stability by adding a small amount of solid particles, the consumption of the emulsifier is greatly reduced, and the raw material cost is saved. In addition, the solid colloid particles are nontoxic and environment-friendly, and generally do not need post-treatment; by means of the nature of the colloidal particles, it is also possible to impart certain unique properties to the material, such as antimicrobial effects, adsorption effects, etc.

In the research field of the material, CN109312091a discloses a method for preparing high internal phase emulsion foam by using modified cellulose nano particles, which indicates that the mechanical properties of the foam can be improved by modifying cellulose nano particles, and examples show the stability of emulsion prepared by different modified cellulose nano particles and the change of compression modulus of the foam obtained after solidification. US20100261803A1 discloses a process for the preparation of a high internal phase emulsion stabilised with particles having an amphiphilic nature, which indicates that the high internal phase emulsion can be stabilised with particles of amphiphilic silica or titanium oxide, and describes the physical morphology and structure of the foam after solidification of such emulsions, which patent mentions that the hydrophobically modified particles can be used to stabilise the high internal phase emulsion, but the prepared foam is highly hydrophobic and unsuitable for use as an absorbent material for hygiene articles, and is limited only to hipe systems having an internal phase volume fraction of 92% or less, nor is the definition made of the absorption properties and influencing conditions necessary for the application of the foam to absorbent materials for disposable hygiene articles, except that under the conditions of preparation, the open and closed pores and pore size of the foam prepared from the emulsion stabilised with amphiphilic particles are analysed in relation to each other.

The nano zinc oxide can destroy cell membranes in bacteria and viruses, so that bacterial substances are lost, viral proteins are solidified, harmful compounds released on bacterial and viral residues can be decomposed while disinfection and sterilization are performed, the nano zinc oxide has a strong killing effect on bacteria, mold and viruses, and the nano zinc oxide also has a deodorizing effect. However, the antibacterial deodorizing effect of the nano zinc oxide is not obvious when the adding amount is low, the prepared foam material is easy to cause strong hydrophobicity and is unfavorable for absorbing hydrophilic fluid when the adding amount is high, and the foam surface has obvious powder feel and poor hand feeling when the zinc oxide content is high.

Therefore, there is a need to solve the defect that the hydrophobicity and antibacterial property of the foam prepared by adopting nano zinc oxide are not balanced.

Disclosure of Invention

The invention aims to provide a method for preparing an antibacterial foam absorbing material by utilizing HIPPE, which can be applied to disposable sanitary products, and has the advantages of low reverse osmosis amount, less emulsifier consumption, higher strength, good antibacterial property and the like compared with the absorbing foam material prepared by HIPE disclosed by the prior art.

It is still another object of the present invention to provide a HIPPE bacteriostatic foam absorbent material with good absorbability and mechanical properties, and antibacterial and deodorant properties, which is prepared by the method.

It is a further object of the present invention to provide the use of such bacteriostatic foam absorbent material in the field of disposable hygiene products.

In order to achieve the above object, the present invention adopts the following technical scheme:

a method of preparing a bacteriostatic foam absorbent material from hipe comprising the steps of:

1) Dispersing an oil phase containing hydrophobic modified nano zinc oxide accounting for 1-5% of the total weight of the oil phase and cellulose nano particles accounting for 0.2-5% of the total weight of the oil phase, a monomer component and an emulsifier into a uniform phase;

2) Adding the water phase containing the electrolyte into the oil phase under the shearing action, and emulsifying to form stable ultra-high internal phase Pickering emulsion;

3) Solidifying the Pickering emulsion for preparing the ultra-high internal phase, and extruding, dehydrating and drying the solidified foam to obtain the antibacterial foam absorbing material.

In a specific embodiment, in said step 1), the oil phase comprises, based on the total weight of said oil phase:

a) 85% to 96% by weight of a substantially water insoluble monomer component;

b) 1-10% by weight of an emulsifier component which is soluble in the oil phase and which forms a stable water-in-oil emulsion;

c) 1-5 wt% of hydrophobically modified nano zinc oxide particles;

d) 0.2% -5% by weight of cellulose nanoparticles;

in a preferred embodiment, the monomer component of a) comprises:

i) From 60% to 95% by weight, based on the total weight of monomer components contained in the oil phase, of at least one monofunctional comonomer that is substantially insoluble in water; the monofunctional comonomer is preferably selected from any one or combination of styrene, alkyl acrylate and alkyl methacrylate; more preferably, from 70% to 90% by weight of at least one substantially water insoluble monofunctional comonomer; the monofunctional comonomer is preferably selected from acrylic acid C ₄ -C ₁₈ Alkyl esters, methacrylic acid C ₄ -C ₁₈ Any one or a combination of alkyl ester, styrene, and alkylstyrene;

ii) from 5% to 40% by weight, based on the total weight of monomer components contained in the oil phase, of at least one substantially water-insoluble polyfunctional crosslinking agent; the multifunctional crosslinking agent is preferably any one or a combination of divinyl aromatic, alkyl acrylamide, diacrylate or dimethacrylate of polyalcohol; more preferably, 10% to 30% by weight of at least one substantially water insoluble polyfunctional crosslinker, preferably selected from any one or combination of divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, ethylene glycol dimethacrylate, 1, 4-butanediol dimethacrylate, 1, 6-hexanediol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, hexanediol dimethacrylate, 1, 12-dodecanedimethacrylate, 1, 14-tetradecanediol dimethacrylate.

In a specific embodiment, the particle size of the hydrophobically modified nano zinc oxide is from 1nm to 100nm, preferably the hydrophobically modified nano zinc oxide is selected from C ₉ -C ₂₄ Any one of long-chain saturated or unsaturated fatty acid modified nano zinc oxide, organic silicon modified nano zinc oxide, silane coupling agent modified nano zinc oxide, titanate coupling agent modified nano zinc oxide, surfactant modified nano zinc oxide and polyethylene glycol modified nano zinc oxide; more preferably, the addition amount of the hydrophobically modified nano zinc oxide accounts for 1% -3% of the total weight of the oil phase.

In a specific embodiment, the cellulose nanoparticle is selected from at least any one of cellulose nanocrystals, microcrystalline cellulose, cellulose nanofibers, nanocrystalline cellulose, nanocellulose, nanofibrillated cellulose, or bacterial nanocellulose; more preferably, the addition amount of the cellulose nano particles accounts for 0.5% -2% of the total weight of the oil phase.

In a specific embodiment, the emulsifier is selected from branched or straight chain C ₁₆ -C ₂₄ Fatty acid glycerides, branched or straight chain C ₁₆ -C ₂₄ Any one or a combination of fatty acid sorbitan fatty acid ester, sucrose fatty acid ester and alkylphenol ethoxylate; preferably, the weight ratio of the volume of the water phase to the oil phase is 10 mL-40 mL:1g.

In a specific embodiment, the aqueous phase in step 2) comprises:

a) 0.5-15% by weight, based on the weight of the aqueous phase, of a water-soluble electrolyte which is a water-soluble inorganic salt; preferably, the water-soluble inorganic salt is selected from monovalent, divalent inorganic salts of alkali metal and alkali metal halide or sulfate salts;

b) Based on the total weight of monomer components of the oil phase, a water-soluble or oil-soluble initiator accounting for 1-10% of the total weight of the monomer components; preferably, the initiator is selected from any one of a photoinitiator, persulfate, azobisiso Ding Mi hydrochloride or redox initiation system; more preferably, the photoinitiator is selected from at least any one of diphenyl ketone, alpha-hydroxyacetophenone, benzyl ketal, alpha-aminoalkyl benzophenone or acyl phosphine oxide; the persulfates, azo diiso Ding Mi hydrochloride or redox initiation system is selected from at least any one of sodium persulfate, ammonium persulfate, potassium persulfate, azo diisobutyl imid hydrochloride, azo diiso Ding Mi hydrochloride or persulfate-sodium hydrogen sulfite, persulfate-ascorbic acid and persulfate-sodium thiosulfate;

In a preferred embodiment, the aqueous phase of step 2) is added to the oil phase under shear at an emulsification temperature of 40℃to 90℃and a mixing shear rate of 100rpm to 2000rpm to form a stable water-in-oil emulsion.

In a specific embodiment, the high internal phase Pickering emulsion formed in step 3) is put into an oven, water bath or hot steam for curing at a temperature of 40-120 ℃ for no more than 0.5 hour, and the residual monomer content of the foam after curing is less than 500ppm based on the weight of the polymer.

On the other hand, the antibacterial foam absorbent material prepared by the method is preferable that the contact angle of the antibacterial foam absorbent material to normal saline is less than 100 degrees, and the reverse osmosis amount is less than 0.2 gram; more preferably, the antibacterial foam absorbent material has a glass transition temperature of-30 ℃ to 30 ℃ and a cell number average diameter of 10 μm to 150 μm.

In a specific embodiment, the antibacterial foam absorbent material has an antibacterial rate of more than 70% on escherichia coli, staphylococcus aureus and candida albicans after 1 hour of antibacterial test.

In a further aspect, the bacteriostatic foam absorbent material produced by the method or the use of the bacteriostatic foam absorbent material in disposable sanitary products, preferably feminine napkins, baby diapers (pads), adult incontinence products, pet pads or disposable medical sanitary products.

Compared with the prior art, the invention has the following beneficial effects:

the invention utilizes hydrophobic modified nano zinc oxide and cellulose nano particles to jointly stabilize HIPPE emulsion with ultra-high internal phase, solves the problems of high addition amount of an emulsifying agent and single performance in the existing foam absorbing material preparation process, prepares the open-cell antibacterial porous foam absorbing material, has lower reverse osmosis amount to physiological saline, lower addition amount of the emulsifying agent and higher foam strength compared with the common HIPE foam preparation process, and has better antibacterial property and better application performance in the disposable sanitary article due to the addition of the hydrophobic modified nano zinc oxide.

According to the method, stable HIPPE emulsion is formed by the hydrophobically modified nano zinc oxide and cellulose nano particles, so that a porous foam material is formed, the cellulose nano particles do not need to be modified, the addition of the cellulose nano particles is used for improving the hydrophilicity of the foam material, experiments show that the addition of the cellulose nano particles and the hydrophobically modified nano zinc oxide are mutually restricted, when the addition of the modified zinc oxide is too high, the hydrophilicity of the material is not improved by the cellulose, and when the addition of the cellulose is too high, the emulsion cannot be emulsified and is stable, and the addition of the cellulose and the modified zinc oxide needs to be balanced; in addition, the HIPPE foam after the addition of the cellulose nano-particles has smaller water contact angle and lower reverse osmosis amount than the common HIPE foam.

According to the invention, the HIPPE emulsion is prepared by adopting the hydrophobic modified nano zinc oxide and the cellulose nano particles, the addition amount of the emulsifier is greatly reduced on the premise of unchanged water-oil ratio and monomer composition, the addition amount of the emulsifier can be reduced to below 50% of the original addition amount, the emulsion stability is higher, and the water-oil separation is not easy to occur. The hydrophobic modified nano zinc oxide can stabilize emulsion, endow the cured foam material with good antibacterial and deodorizing effects, the cellulose can improve the hydrophilicity of the foam and the strength of the foam, and neutralize the adverse effect of strong hydrophobicity caused by the modified zinc oxide.

Drawings

FIG. 1 is an SEM spectrum (magnification of 5000) of the foam prepared according to comparative example 2 of the present invention;

FIG. 2 is an SEM spectrum (magnification of 1000) of the foam prepared according to example 1 of the invention;

FIG. 3 is an SEM spectrum (magnification of 5000) of the foam prepared according to comparative example 5 of the present invention;

FIG. 4 is a DMA chart of the foams prepared in example 1 and comparative examples 2 and 4 of the present invention.

Detailed Description

The following examples will further illustrate the method provided by the present invention for a better understanding of the technical solution of the present invention, but the present invention is not limited to the examples listed but should also include any other known modifications within the scope of the claims of the present invention.

A method for preparing a bacteriostatic foam absorbing material by utilizing HIPPE stabilized by hydrophobically modified nano zinc oxide and cellulose nano particles comprises the following steps:

1) Preparing a water-in-oil emulsion comprising an oil phase, wherein the oil phase comprises, based on the total weight of the oil phase:

a) 85 to 96 weight percent of a substantially water insoluble monomer component, "substantially water insoluble" in the present invention means that the monomer is slightly soluble, poorly soluble or insoluble in water at 20 ℃;

c) 1-5% by weight of hydrophobically modified nano zinc oxide particles having a particle size of 1-100 nm;

d) 0.2% -5% by weight of cellulose nanoparticles;

specifically, the oil phase is ultrasonically treated to be uniform in an ultrasonic oscillator, and the temperature of the oil phase is maintained at 20-50 ℃;

2) The water phase comprises 0.5-15 wt% of water-soluble inorganic salt based on the total weight of the water phase, and the temperature of the water phase is maintained at 40-90 ℃; gradually adding the water phase into the oil phase under the shearing action to emulsify the water phase into stable HIPPE emulsion;

3) Solidifying the water-in-oil emulsion to form a foam; curing is preferably carried out by placing in an oven, water bath or steam; and washing, dehydrating and drying the solidified foam to obtain the high internal phase emulsion foam material.

In another specific embodiment, the method comprises the following preparation steps:

1) At 20-50 ℃, forming a stable and uniform oil phase by the oil phase containing the hydrophobic modified nano zinc oxide, the cellulose nano particles, the monomer component and the emulsifier under the ultrasonic action;

2) Mixing the oil phase as a continuous phase with the aqueous phase as a dispersed phase containing an electrolyte at a temperature of 40 ℃ to 90 ℃, preferably 40 ℃ to 80 ℃, to form a stable hipe water-in-oil emulsion;

3) Placing the HIPPE emulsion in an oven or water bath or under UV illumination to cure for 30s-30 min; washing, squeezing and dehydrating the solidified foam, and finally drying the foam in a vacuum oven at 60 ℃ for 3 hours.

Wherein in step 1), the hydrophobically modified nano zinc oxide is contained in the oil phase in an amount of 1% -5% by weight of the total oil phase, including, but not limited to, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.0% by weight of the total oil phase, and more preferably the hydrophobically modified nano zinc oxide is contained in the oil phase in an amount of 1% -3% by weight of the total oil phase.

The hydrophobic modified nano zinc oxide component, preferably with the particle size of 1-100nm, can be selected from long-chain fatty acid modified nano zinc oxide, organosilicon modified nano zinc oxide, surfactant modified nano zinc oxide, polyethylene glycol modified nano zinc oxide, various inorganic particle hybridized nano zinc oxide or zinc oxide particles modified in any other way to achieve the aim of changing the surface hydrophilicity and hydrophobicity; preferably, the hydrophobic modified nano zinc oxide is C9-C24 long chain saturated or unsaturated fatty acid modified nano zinc oxide, organosilicon modified nano zinc oxide, silane coupling agent modified nano zinc oxide, titanate coupling agent modified nano zinc oxide, surfactant modified nano zinc oxide, polyethylene glycol modified nano zinc oxide or other modified zinc oxide particles modified in any way so as to achieve the aim of changing the surface hydrophilicity and hydrophobicity; more preferably, any one or a mixture of more than one of lauric acid modified nano zinc oxide, stearic acid modified nano zinc oxide, silane coupling agent or titanate coupling agent modified nano zinc oxide, surfactant modified nano zinc oxide, chitosan modified nano zinc oxide, polyethylene glycol modified nano zinc oxide and titanate coupling agent modified nano zinc oxide is selected.

In step 1), the cellulose nanoparticles contained in the oil phase comprise, for example, but not limited to, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5.9%, preferably, and the cellulose nanoparticles comprise more preferably comprise 2.5% of the total weight of the oil phase, and the total weight of the cellulose nanoparticles comprises, preferably comprises 2.5% of the total weight of the oil phase.

The cellulose nanoparticle may be selected from any one or any combination of microcrystalline cellulose, nanocrystalline cellulose, nanocellulose, cellulose nanocrystals, nanofibrillated cellulose, bacterial nanocellulose, cellulose nanofibers, and the like. The cellulose particles may have a diameter between 1nm and 20000 nm.

In step 1), the substantially water-insoluble monomer component contained in the oil phase comprises 85% to 96% of the total weight of the oil phase, including, but not limited to, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, preferably 90% to 96% of the total weight of the oil phase.

Wherein the monomer component comprises: i) From 60% to 95% by weight, based on the total weight of monomer components contained in the oil phase, of at least one substantially water-insoluble monofunctional comonomer; preferably, the monofunctional comonomer is selected from the group consisting of styrene, alkyl acrylate, alkyl methacrylate, aryl acrylate, and mixtures thereof; more preferably, 70% to 90% by weight of a monomer component selected from the group consisting of: acrylic acid C ₄ -C ₁₈ Alkyl esters, methacrylic acid C ₄ -C ₁₈ Alkyl ester esters, styrene, alkylstyrenes and mixtures thereof. Such as butyl acrylate, isooctyl acrylate, n-octyl acrylate, n-hexyl acrylate, nonyl acrylate, decyl acrylate, isodecyl acrylate, dodecyl acrylate, tetradecyl acrylate, hexyl methacrylate, isooctyl methacrylate, decyl methacrylate, isodecyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate or octadecyl methacrylate; the monomer component may also contain water insoluble comonomers such as vinyl chloride, isoprene or chloroprene.

ii) from 5% to 40% by weight, based on the total weight of monomer components contained in the oil phase, of at least one substantially water-insoluble polyfunctional crosslinking agent; for example, including but not limited to, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% by weight of the total monomer weight of at least one substantially water insoluble polyfunctional crosslinker selected from the group consisting of divinyl aromatics, diacrylates or dimethacrylates of polyols, and mixtures thereof; more preferably, from 10% to 30% by weight of a multifunctional crosslinker selected from any one of divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, 1, 4-ethyleneglycol dimethacrylate, 1, 6-hexanediol dimethacrylate, ethyleneglycol dimethacrylate, hexanediol dimethacrylate, and the like, or a mixture of these components, the crosslinker component being capable of providing the desired elasticity and strength of the foam.

In step 1), the oil phase comprises 1% -10% by weight of the total weight of the oil phase of an emulsifier component which is soluble in the oil phase and forms a stable water-in-oil emulsion, including, but not limited to, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% by weight of the total weight of the oil phase of an emulsifier component which is soluble in the oil phase and forms a stable water-in-oil emulsion, in particular the oil soluble emulsifier is selected from branched or straight chain C ₁₆ -C ₂₄ Fatty acid glycerides, branched or straight chain C ₁₆ -C ₂₄ Fatty acid sorbitan fatty acid esters, sucrose fatty acid esters, alkylphenol ethoxylates, or mixtures of these components, such as sorbitan monooleate, sorbitan laurate, bis (poly) glyceryl stearate, bis (poly) glyceryl monooleate, polyglyceryl succinate, sucrose stearate, and the like.

In the step 2), the stable HIPPE water-in-oil emulsion refers to the phenomenon that the stable HIPPE water-in-oil emulsion can be stably placed for more than 20 minutes under the experimental temperature condition and is generated by the phenomenon of anhydrous oil separation. The mixing shear rate of the oil phase and the water phase is 100rpm to 2000rpm, including for example but not limited to 100rpm, 300rpm, 500rpm, 700rpm, 900rpm, 1100rpm, 1300rpm, 1500rpm, 1700rpm, 1900rpm, 2000rpm, more preferably 200 to 1500rpm; the mass ratio of the volume of the water phase to the oil phase is 10 mL-40 mL:1g, for example, includes but is not limited to 10mL:1g, 15mL:1g, 20mL:1g, 25mL:1g, 30mL:1g, 35mL:1g, 40mL:1g; more preferably, the mass ratio of the volume of the aqueous phase to the oil phase is 20mL:1 g-40 mL:1g.

In step 2), the aqueous phase contains 0.5% -15% by weight of a water-soluble electrolyte, including, for example, but not limited to, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% by weight of a water-soluble electrolyte, which is an inorganic water-soluble salt selected from calcium chloride, magnesium chloride, or magnesium sulfate, calcium sulfate. The water-soluble electrolyte can minimize the solubility of the monomer and the crosslinking agent in water, and the size and the number of pores in the foam can be controlled by adjusting the addition amount of the electrolyte.

In step 2), the aqueous phase contains 1% -10% by weight of the total monomer of a water-soluble or oil-soluble initiator, including, for example, but not limited to, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10% by weight of the total monomer of a water-soluble or oil-soluble initiator selected from the group consisting of photoinitiators or thermal initiators or redox pair initiators, and the optional photoinitiator is selected from the group consisting of benzophenone, α -hydroxyalkylacetone (trade name 1173), benzyl ketal, α -aminoalkylphenone, acylphosphine oxides, and the like; or a thermal initiator such as persulfate or azobisiso Ding Mi hydrochloride, e.g., ammonium persulfate, sodium persulfate, potassium persulfate, azobisisobutylimidine hydrochloride, azobisiso Ding Mi hydrochloride, etc., and may also be selected from at least any one of redox initiation systems, e.g., sodium persulfate, ammonium persulfate, potassium persulfate, azobisisobutylimidine hydrochloride, azobisiso Ding Mi hydrochloride, or persulfate-sodium bisulfite, persulfate-ascorbic acid, persulfate-sodium thiosulfate, etc.; preferably selected from photoinitiators comprising: benzophenone, 1-hydroxycyclohexyl phenyl ketone (trade name 184), 2-methyl-2- (4-morpholino) -1- [4- (methylthio) phenyl ] -1-propanone, 2-isopropylthioxanthone, α -hydroxyalkyl acetones (trade name 1173), benzyl ketal, α -aminoalkylphenones, and acylphosphine oxides (e.g., TPO) and the like which are soluble in the oil phase; or may be 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-propanone, 2-azobis [2- (2-imidazolin-2-yl) propane ] dihydrochloride or sulfate, thioxanthone derivatives (such as trade name TX) etc. dissolved in the aqueous phase; preferably in the present invention the photoinitiator is benzophenone or 1173.

In step 3), the emulsified high internal phase Pickering emulsion prepared in step 2) is placed in a curing vessel made of polymethyl methacrylate or polyethylene or polypropylene or polytetrafluoroethylene at a thickness of 0.5 to 0.5 mm, and in an oven or water bath or under UV light irradiation, preferably at a curing temperature of 40 to 120 ℃ for 30 seconds to 30 minutes, after curing, the monomer conversion (calculated as the weight percentage of unreacted residual monomers to the total monomers) in the oil phase is not lower than 85%, and the residual monomer content of the cured foam is lower than 500ppm based on the weight of the polymer.

The solidified foam is washed with deionized water, and then is extrusion dehydrated by a press roller, and the washing and extrusion dehydration processes can be repeated several times, for example, 1 time, 2 times, 3 times, 4 times, 5 times or more, and the water content of the foam after extrusion dehydration is not higher than 50% of the weight of the foam material.

The foam after one or more times of washing, extrusion and dehydration is preferably dried for 3 hours in an oven or vacuum oven at 60 ℃ to 100 ℃, the water content of the dried foam is not higher than 20% of the total weight of the foam, and the thickness of the dried foam is 0.5-8mm.

The HIPPE foam absorbing material prepared by the method has the glass transition temperature of-30 ℃ to 30 ℃, the number average diameter of the cells of 10 mu m to 150 mu m, preferably, the number average diameter of the cells of the foam material is 10 mu m to 100 mu m, and the number average diameter of the window holes between adjacent cells is lower than 20 mu m; more preferably, the foam polymer has a Tg of-20 ℃ to 20 ℃. Meanwhile, the antibacterial rate of the prepared foam absorbing material on escherichia coli, staphylococcus aureus, candida albicans and other strains can reach more than 70% after 1 hour in an antibacterial test; and the contact angle of the foam material to normal saline is less than 100 degrees, and the reverse osmosis amount is less than 0.2 gram. In view of the aforementioned characteristics of bacteriostasis, etc., the HIPPE foam material prepared in the present invention is particularly suitable for use as disposable sanitary absorbent articles, preferably for use in infant diapers/pads, feminine sanitary napkins, adult incontinence products, medical bandages, pet pads, and the like.

All the raw materials of the invention are not particularly specified and can be purchased from the market.

The properties of the foams prepared in the present invention were tested and characterized using the methods described below:

a) Test liquid

The test liquid used in all the tests in the present invention was 0.9% physiological saline as the test liquid. The formulation and physical properties of physiological saline can be described in the national standard G/T22875-2018. The test liquid is maintained at a temperature of (36.+ -. 1) ℃ throughout the test, and a small amount of food coloring may be added to the test liquid for easy observation and identification during the test.

B) Preparation of foam samples

The cured foam sample is cut into rectangles with the length and the width of 8 cm х cm, and the cutting is carried out while avoiding the part of the foam surface with particularly large holes or cracks or concave-convex parts, so that the size and the surface morphology of each foam sample are basically consistent. The measurement of the foam thickness was measured using a sponge thickness gauge.

C) Determination of number average cell diameter

The form and cell size of the foam sample are measured by a scanning electron microscope, at least more than 50 cell diameters are measured in a proper visual field range, and the average value is the number average cell diameter of the sample.

D) Determination of absorption Rate and reverse osmosis

Weighing and recording a certain mass of filter paper, sucking 5 milliliters of test liquid by using a liquid-transferring gun, injecting the test liquid into the central position of a test sample, starting timing at the same time, and recording the disappearance time of the liquid; after 5 minutes, the weighed filter paper is placed at the liquid adding position of the test sample, the pressure is applied for 1 minute by using a weight of 500g, and then the weight of the filter paper after imbibition is weighed, and the weight difference of the filter paper is the reverse osmosis value.

E) Measurement of contact Angle

The hydrophilicity and hydrophobicity of the foam surface are characterized by testing the contact angle of physiological saline on the foam sample surface by using a video optical contact angle tester of Dataphysics model OCA25, and the contact angle result is calculated by a three-point method. Each sample was tested 3 times in duplicate and the average of the 3 test results was taken.

F) Determination of the bacteriostatic Rate

Cutting an experimental sample and a comparison sample with the size of 2.0cm х 3.0.0 cm, dropwise adding 100uL of bacterial suspension on the surface for antibacterial performance test, wherein the test bacteria are escherichia coli, staphylococcus aureus and candida albicans as test bacteria, and counting the number of viable bacteria after culturing for 1h and 24 h. The test was repeated 3 times, and the bacteriostasis rate was calculated and the average value was taken.

G) Dynamic mechanical analysis of foam (DMA)

The foam sample was cut into cylinders of 1 cm diameter and 3 mm thickness, and the Young's modulus of the foam material was measured in compression mode using a Dynamic Mechanical Analyzer (DMA) at a temperature ranging from-60℃to 60℃and the mechanical properties of the foam material were characterized by a compression modulus E'.

H) Testing of glass transition temperature

Glass transition temperature the glass transition temperature of the foam sample in the invention is measured by using thermo-mechanical analysis (TMA), and the foam sample is cut into cuboid sample pieces with the size of 10mm multiplied by 5mm multiplied by 1mm by using a METTLER TMA/SDTA instrument (compression mode) so as to ensure the upper surface and the lower surface to be flat. And placing the sample on an inner bracket of the instrument, placing a quartz gasket on the upper surface of the sample, and lowering the probe to start the test.

The technical scheme of the present invention is further described below with reference to specific examples, but is not limited in any way.

Example 1

A) Preparation of HIPPE emulsions

Stearic acid modified nano zinc oxide (available from darcy nanotechnology limited, 50nm,0.28 g) and microcrystalline cellulose (available from Adamas,0.23 g) were ultrasonically dispersed at room temperature in an oil phase mixed with isooctyl acrylate (15.0 g), ethylene glycol dimethacrylate (5.0 g), benzophenone (1.0 g) and citrol DPHS (PEG-30 dimer hydroxystearate available from CRODA,1.2 g) to give a homogeneous oil phase. Calcium chloride (25.0 g) was dissolved in 605 ml deionized water to prepare an aqueous phase.

Placing the obtained oil phase into a polypropylene container with a volume of 1 liter, stirring the oil phase by using an IKA stirrer, wherein the stirring paddle is an anchor stirring paddle made of polytetrafluoroethylene, the total length of the paddle is about 5 cm, stirring the oil phase at a rotating speed of 100 revolutions per minute is started, simultaneously adding all water phases within 5 minutes, preheating the water phases to 60 ℃ in advance, adding circulating water outside a dispersing container for heat preservation, and setting the temperature of the circulating water to 60 ℃; the stirring speed is gradually increased along with the addition of the water phase, and the rotating speed is about 300 rpm after the addition of the whole water phase, so that stable and delamination-free high internal phase emulsion is formed.

B) Curing of high internal phase emulsions

The prepared high internal phase emulsion is poured into a polytetrafluoroethylene solidifying mold, the length of the mold is 24 cm, the width of the mold is 10 cm, and the thickness of the emulsion is 2 mm. The cured mold was placed in a UV box (wavelength 365 nm) and was then exposed to light for 90 seconds and removed.

C) Washing, dewatering and drying of foam

Taking out the solidified foam, directly washing with deionized water at normal temperature, removing residual emulsifying agent and inorganic salt, and squeezing and dehydrating with a rubber press roller, wherein the washing and squeezing and dehydrating processes can be repeated for several times according to actual conditions. And (5) drying the dehydrated foam in a vacuum oven at 60 ℃ for 3 hours, and then taking out. The moisture content of the foam is now less than 20% (based on the weight of the dry foam).

Example 2

A) Preparation of high internal phase Pickering emulsion

Lauric acid modified nano zinc oxide (available from darcy nanotechnology limited, 30nm,0.34 g) was ultrasonically dispersed in an oil phase mixed with lauryl acrylate (17.0 g), divinylbenzene (3.0 g), cellulose nanofibers (available from shimeji technology, 0.12 g) and sucrose fatty acid ester S-370 (available from mitsubishi chemical, 0.7 g), photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone 1173 (Shanghai Kaiyi chemical, 1.2 g), resulting in a homogeneous mixed oil phase. Sodium chloride (10.0 g) was dissolved in 350 ml deionized water to prepare an aqueous phase.

Placing the obtained oil phase into a polypropylene container with a volume of 1 liter, stirring the oil phase by using an IKA stirrer, wherein the stirring paddle is an anchor stirring paddle made of polytetrafluoroethylene, the total length of the paddle is about 5 cm, stirring the oil phase at a rotating speed of 200 revolutions per minute is started, simultaneously adding all water phases within 5 minutes, preheating the water phases to 55 ℃ in advance, adding circulating water outside a dispersing container for heat preservation, and setting the circulating water to 55 ℃; the stirring speed is gradually increased along with the addition of the water phase, and the rotating speed is about 700 rpm after the addition of the whole water phase, so that stable and delamination-free high internal phase emulsion is formed.

B) Curing of high internal phase emulsions

The prepared high internal phase emulsion is poured into a curing mold made of polyethylene, the length of the mold is 24 cm, the width of the mold is 10 cm, and the thickness of the emulsion is 1 mm. The curing mold was placed in a UV box and taken out after 60 seconds of illumination.

C) Washing, dewatering and drying of foam

The subsequent post-treatment process conditions were all identical to those of example 1.

Example 3

A) Preparation of high internal phase Pickering emulsion

Organosilicon modified nano zinc oxide (20 nm,0.46 g, available from Yumu New Material Co., ltd.) and cellulose nanocrystals (0.48 g, available from Siden) were ultrasonically dispersed in an oil phase mixed with isodecyl acrylate (12.0 g), isooctyl methacrylate (2.0 g), divinylbenzene (6.0 g), and glycerol succinate (1.7 g, available from Guozhong Co., ltd.) to give a homogeneous oil phase. Magnesium chloride (22.0 g) was dissolved in 480 ml deionized water to prepare an aqueous phase; 0.6 g of V-50 (azobisisobutyronidine hydrochloride, shanghai Sibao Biotechnology) was weighed out and dissolved in 15 ml of deionized water to prepare an initiator phase.

Placing the obtained oil phase into a polypropylene container with a volume of 1 liter, stirring the oil phase by using an IKA stirrer, wherein the stirring paddle is an anchor stirring paddle made of polytetrafluoroethylene, the total length of the paddle is about 5 cm, stirring the oil phase at a rotating speed of 180 revolutions per minute is started, simultaneously adding all water phases within 5 minutes, preheating the water phases to 70 ℃ in advance, adding circulating water outside a dispersing container for heat preservation, and setting the circulating water to 70 ℃; the stirring speed was gradually increased with the addition of the aqueous phase, the rotation speed was around 600 rpm after the addition of the entire aqueous phase, and after the formation of a stable, delamination-free high internal phase emulsion, the initiator solution was added and stirred for an additional 2 minutes.

B) Curing of high internal phase emulsions

The prepared high internal phase emulsion is poured into a curing mold made of polypropylene, the length of the mold is 24 cm, the width of the mold is 10 cm, and the thickness of the emulsion is 1.9 mm. The curing mold was placed in a 90 ℃ oven for 20 minutes and then removed.

C) Washing, dewatering and drying of foam

The subsequent curing process and post-treatment process conditions were exactly as in example 1.

Example 4

A) Preparation of high internal phase Pickering emulsion

Silane coupling agent KH-570 modified nano zinc oxide (30 nm,0.58 g from Yumu New material Co., ltd.) and microfibrillated cellulose (0.69 g from Guogui) were ultrasonically dispersed in an oil phase mixed with octadecyl methacrylate (13.0 g), trimethylolpropane triacrylate (7.0 g) and diglycerol fatty acid ester (1.93 g from Allatin) to give a uniform oil phase. Calcium chloride (100.0 g) was dissolved in 730 ml deionized water to prepare an aqueous phase; VA-044 (available from Japan and light, 0.4 g) was weighed and dissolved in 10 ml deionized water to prepare an initiator phase.

Placing the obtained oil phase into a polypropylene container with a volume of 1 liter, stirring the oil phase by using an IKA stirrer, wherein the stirring paddle is an anchor stirring paddle made of polytetrafluoroethylene, the total length of the paddle is about 5 cm, stirring the oil phase at a rotating speed of 140 revolutions per minute is started, simultaneously adding all water phases within 5 minutes, preheating the water phases to 60 ℃ in advance, adding circulating water outside a dispersing container for heat preservation, and setting the temperature of the circulating water to 60 ℃; the stirring speed was gradually increased with the addition of the aqueous phase, the rotational speed was around 500 rpm after the addition of the entire aqueous phase, and after the formation of a stable, delamination-free high internal phase emulsion, the initiator solution was added and stirred for an additional 2 minutes.

B) Curing of high internal phase emulsions

The prepared high internal phase emulsion is poured into a curing mold made of polypropylene, the length of the mold is 24 cm, the width of the mold is 10 cm, and the thickness of the emulsion is 1.0 mm. The curing mold was placed in a 90 ℃ oven for 25 minutes and then removed.

C) Washing, dewatering and drying of foam

Example 5

A) Preparation of high internal phase Pickering emulsion

Cetyl trimethylammonium bromide modified nano zinc oxide (40 nm,0.86 g from darcy nanotechnology limited) and nanocellulose (0.36 g from kappa, shanghai) were ultrasonically dispersed in an oil phase mixed with isooctyl acrylate (18.5 g), 1, 6-hexanediol dimethacrylate (1.5 g) and Span 20 (0.2 g), span 80 (2.1 g), resulting in a homogeneous oil phase. An aqueous phase was prepared by dissolving magnesium sulfate (10.0 g), photoinitiator 2959 (0.9 g) in 690 ml deionized water.

Placing the obtained oil phase into a polypropylene container with a volume of 1 liter, stirring the oil phase by using an IKA stirrer, wherein the stirring paddle is an anchor stirring paddle made of polytetrafluoroethylene, the total length of the paddle is about 5 cm, stirring the oil phase at a rotating speed of 100 revolutions per minute is started, simultaneously adding all water phase within 5 minutes, preheating the water phase to 76 ℃ in advance, adding circulating water outside a dispersing container for heat preservation, and setting the temperature of the circulating water to 76 ℃; the stirring speed is gradually increased along with the addition of the water phase, and the rotating speed is about 600 rpm after the addition of the whole water phase, so that the stable high internal phase emulsion without layering is formed.

B) Curing of high internal phase emulsions

The prepared high internal phase emulsion is poured into a curing mold made of polypropylene, the length of the mold is 24 cm, the width of the mold is 10 cm, and the thickness of the emulsion is 2.5 mm. The curing mold was placed in a UV box and taken out after 120 seconds of illumination.

C) Washing, dewatering and drying of foam

Example 6

A) Preparation of high internal phase Pickering emulsion

Polyethylene glycol modified nano zinc oxide (available from darcy nanotechnology limited, 60nm,1.08 g) and cellulose nanofibrils (available from aletin, 45nm diameter, 0.99 g) were ultrasonically dispersed in an oil phase mixed with octadecyl acrylate (16.0 g), ethylene glycol dimethacrylate (3.0 g), styrene (1.0 g), 1173 (1.2 g) and polyglycerol stearate (available from Shanghai Kain, 1.6 g) to give a homogeneous oil phase. The aqueous phase was prepared by dissolving calcium chloride (82.0 g) in 920 ml deionized water.

Placing the obtained oil phase into a polypropylene container with a volume of 1 liter, stirring the oil phase by using an IKA stirrer, wherein the stirring paddle is an anchor stirring paddle made of polytetrafluoroethylene, the total length of the paddle is about 5 cm, stirring the oil phase at a rotating speed of 180 revolutions per minute is started, simultaneously adding all water phases within 5 minutes, preheating the water phases to 65 ℃ in advance, adding circulating water outside a dispersing container for heat preservation, and setting the circulating water to 65 ℃; the stirring speed is gradually increased along with the addition of the water phase, and the rotating speed is about 550 r/min after the addition of the whole water phase, so that the stable high internal phase emulsion without layering is formed.

B) Curing of high internal phase emulsions

The prepared high internal phase emulsion is poured into a curing mold made of polypropylene, the length of the mold is 24 cm, the width of the mold is 10 cm, and the thickness of the emulsion is 1.9 mm. The curing mold was placed in a UV box and taken out after 90 seconds of illumination.

C) Washing, dewatering and drying of foam

Comparative example 1

The stearic acid modified nano zinc oxide in the oil phase in example 1 was replaced with unmodified nano zinc oxide of the same mass and similar particle size distribution, the remaining components and reaction conditions, and the post-treatment process were identical to those in example 1.

Comparative example 2

The stearic acid modified nano zinc oxide and microcrystalline cellulose in the oil phase of example 1 were removed, and only 4.62 grams of DPHS was used to stabilize the emulsion, keeping the water to oil ratio unchanged, and the remaining components and reaction conditions, and post-treatment process were exactly the same as in example 1.

Comparative example 3

The addition amount of the stearic acid modified nano zinc oxide in the oil phase in the example 1 is changed to 0.12 g, the water-oil ratio is kept unchanged, and the rest components and the reaction conditions and the post-treatment process are completely identical to those in the example 1.

Comparative example 4

Microcrystalline cellulose in example 1 was removed, the water-to-oil ratio was maintained, and the remaining components and reaction conditions, and the post-treatment process were identical to those in example 1.

Comparative example 5

The addition amount of the stearic acid modified nano zinc oxide in the oil phase in the example 1 is adjusted to be 1.32 g, the water-oil ratio is kept unchanged, and the rest components and the reaction conditions and the post-treatment process are completely consistent with those in the example 1.

Comparative example 6

The microcrystalline cellulose addition in comparative example 5 was adjusted to 1.0 g, keeping the water-to-oil ratio unchanged, and the remaining components and reaction conditions, and the post-treatment process were completely identical to those in example 1.

Comparative example 7

The addition amount of microcrystalline cellulose in the oil phase in example 1 was adjusted to 0.03 g, the water-oil ratio was kept unchanged, and the remaining components were completely identical to those in example 1 with respect to the reaction conditions and the post-treatment process.

Comparative example 8

The addition of microcrystalline cellulose in the oil phase of example 1 was increased to 1.25 g, keeping the water-to-oil ratio unchanged, and the remaining components and reaction conditions, and the post-treatment process were exactly the same as in example 1.

The prepared foam absorbent material was subjected to performance test, and the results are shown in fig. 1-4 and tables 1-3. It can be seen from fig. 1 to 3 that the modified zinc oxide-added foam of fig. 2 is combined with the zinc oxide particles on the cell walls of fig. 3, compared with the smooth cell walls of the conventional foam of fig. 1, whereas many fine pores (non-fenestrations) appear on the cell walls of the foam of fig. 3 with increasing zinc oxide content, the foam shows brittleness and brittleness, which may be due to insufficient emulsion stability caused by too high zinc oxide content, coalescence of droplets occurs, and pores appear during polymerization.

As can be seen in the DMA plot of fig. 4, the modulus of the foam of example 1 with the addition of cellulose and modified zinc oxide is significantly improved compared to comparative examples 2 and 4, as can be seen from the comparison of the modulus of comparative example 4 with that of example 1, the improvement in modulus of the foam by cellulose is more pronounced. Thus, in addition to improving the hydrophilicity of the foam, the cellulose also has the effect of improving the mechanical properties of the foam in the invention.

Table 1 emulsion preparation stability

Numbering device	Modified nano zinc oxide/g	Cellulose nanoparticles/g	Emulsifier addition/g	Emulsion stability	Foam contact angle/°
						Example 1	0.28	0.23	1.2	Stabilization	51.1
Example 2	0.34	0.12	0.7	Stabilization	69.8
						Example 3	0.46	0.48	1.7	Stabilization	63.5
Example 4	0.58	0.69	1.93	Stabilization	69.7
						Example 5	0.86	0.36	2.3	Stabilization	88.2
Example 6	1.08	0.99	1.6	Stabilization	95.6
						Comparative example 1	0.28 (ordinary ZnO)	0.23	1.2	Water-oil separation	——
Comparative example 2	0	0	4.62	Stabilization	46.2
						Comparative example 3	0.12	0.23	1.2	Stabilization	49.2
Comparative example 4	0.28	0	1.2	Stabilization	112.5
						Comparative example 5	1.32	0.23	1.2	Stabilization	138.2
Comparative example 6	1.32	1.0	1.2	Stabilization	129.3
						Comparative example 7	0.28	0.03	1.2	Stabilization	105.4
Comparative example 8	0.28	1.25	1.2	Water-oil separation	——

As can be seen from table 1, unmodified nano zinc oxide cannot stabilize hipe emulsion, and water-oil separation occurs in the system, so that hydrophobic modified nano zinc oxide is necessary for stabilization; compared with the conventional HIPE foam prepared by the emulsifier only (comparative example 2), the foam prepared by the hydrophobic modified nano zinc oxide has low addition amount of the emulsifier, and the emulsion can keep good stability; when the addition amount of microcrystalline cellulose exceeds 5% (comparative example 8), it was found that the emulsion showed water-oil separation due to the fact that cellulose contained a large amount of hydrophilic groups and was strongly hydrophilic, which is disadvantageous for the stability of the water-in-oil emulsion, so that the addition amount of cellulose nanoparticles in the present invention cannot exceed a given range, otherwise is disadvantageous for the stability of the emulsion. From comparative example 4, it can be seen that the contact angle of the foam increases and the hydrophobicity becomes strong when the cellulose is removed; when the amount of the modified zinc oxide added exceeds 5% (comparative example 5), the hydrophobicity of the foam is still strong even in the presence of cellulose, and an increase in the amount of cellulose added (i.e., comparative example 6) finds that the hydrophilicity of the foam is not improved, and the foam obtained in comparative example 5 has a strong feeling of surface powder, a large foam pore size, and is unsuitable for use as a sanitary absorbent material, so that the amount of the modified zinc oxide added cannot be excessively high. When the amount of cellulose added was less than 0.2%, the improvement in hydrophilicity of the foam of comparative example 7 was not remarkable, indicating that too low an amount of cellulose added did not exert a sufficient effect of improving the hydrophilicity of the foam.

Antibacterial effect of the foam prepared in Table 2

Table 3 prepared foam absorbency

As can be seen from the antibacterial test results of Table 2, the foam of comparative example 2, to which no modified zinc oxide was added, had no antibacterial property, but when the amount of modified zinc oxide added was low, as in comparative example 3, the antibacterial property of the foam was weak, and when the amount of modified zinc oxide added exceeded 1%, the antibacterial property of the foam was good.

As can be seen by combining the absorption properties of the foams of table 3, the absorption rate of the foams prepared from modified zinc oxide together with cellulose was reduced compared to comparative example 2, but the reverse osmosis amount was significantly reduced, probably due to the enhanced hydrophobicity of the foam, and as can be seen by comparing example 1 with comparative example 4, the hydrophobicity of the foam without cellulose was stronger and the absorption rate was rapidly slowed down; when the amount of the modified zinc oxide added exceeds 5%, the foam is completely hydrophobic and cannot absorb physiological saline, and when the amount of the cellulose added is low, the absorption rate of comparative example 7 is slow, and the liquid cannot completely infiltrate into the inside of the foam, resulting in an increase in reverse osmosis.

While the present invention has been described in detail through the foregoing description of the preferred embodiment, it should be understood that the foregoing description is not to be considered as limiting the invention. Those skilled in the art will appreciate that certain modifications and adaptations of the invention are possible and can be made under the teaching of the present specification. Such modifications and adaptations are intended to be within the scope of the present invention as defined in the appended claims.

Claims

1. A method of preparing a bacteriostatic foam absorbent material from hipe comprising the steps of:

1) Dispersing an oil phase containing hydrophobic modified nano zinc oxide accounting for 2.1-5% of the total weight of the oil phase and cellulose nano particles accounting for 0.2-5% of the total weight of the oil phase, a monomer component and an emulsifier into a uniform phase;

2. The method according to claim 1, wherein in step 1), the oil phase comprises, based on the total weight of the oil phase:

a) 85 to 96 weight percent of a water insoluble monomer component;

c) 1-5 wt% of hydrophobically modified nano zinc oxide particles;

d) 0.2% -5% by weight of cellulose nanoparticles.

3. The method of claim 2, wherein the monomer component of a) comprises:

i) From 60% to 95% by weight, based on the total weight of monomer components contained in the oil phase, of at least one monofunctional comonomer that is insoluble in water;

ii) from 5% to 40% by weight, based on the total weight of monomer components contained in the oil phase, of at least one water-insoluble polyfunctional crosslinking agent.

4. A process according to claim 3, wherein the monomer component of a) comprises:

i) From 70% to 90% by weight, based on the total weight of monomer components contained in the oil phase, of at least one monofunctional comonomer insoluble in water;

ii) from 10% to 30% by weight, based on the total weight of monomer components contained in the oil phase, of at least one water-insoluble polyfunctional crosslinking agent.

5. The method according to claim 3 or 4, wherein the monofunctional comonomer is selected from the group consisting of acrylic acid C ₄ -C ₁₈ Alkyl esters, methacrylic acid C ₄ -C ₁₈ Any one or combination of alkyl ester, styrene and alkylstyrene.

6. The method according to claim 3 or 4, wherein the multifunctional crosslinking agent is selected from any one or a combination of divinyl aromatics, alkyl acrylamides, diacrylates or dimethacrylates of polyols.

7. The method of claim 6, wherein the multifunctional crosslinking agent is selected from any one or a combination of divinylbenzene, trivinylbenzene, divinyltoluene, divinylxylene, ethylene glycol dimethacrylate, 1, 4-butanediol dimethacrylate, 1, 6-hexanediol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, hexanediol dimethacrylate, 1, 12-dodecyl dimethacrylate, 1, 14-tetradecyl glycol dimethacrylate.

8. The method of any one of claims 1-4, wherein the hydrophobically modified nano zinc oxide has a particle size of from 1nm to 100nm.

9. The method of claim 8, wherein the hydrophobically modified nano zinc oxide is selected from C ₉ -C ₂₄ Any one of long-chain saturated or unsaturated fatty acid modified nano zinc oxide, organic silicon modified nano zinc oxide, silane coupling agent modified nano zinc oxide, titanate coupling agent modified nano zinc oxide, surfactant modified nano zinc oxide and polyethylene glycol modified nano zinc oxide.

10. The method of claim 9, wherein the hydrophobically modified nano zinc oxide is added in an amount of 2.1% to 3% by weight of the total oil phase.

11. The method of any one of claims 1-4, wherein the cellulose nanoparticle is selected from at least any one of cellulose nanocrystals, microcrystalline cellulose, cellulose nanofibers, nanocrystalline cellulose, nanocellulose, nanofibrillated cellulose, or bacterial nanocellulose.

12. The method of claim 11, wherein the cellulose nanoparticles are added in an amount of 0.5% -2% by weight of the total oil phase.

13. The method according to any one of claims 1 to 4, wherein the emulsifier is selected from branched or linear C ₁₆ -C ₂₄ Fatty acid glycerides, branched or straight chain C ₁₆ -C ₂₄ Any one or combination of fatty acid sorbitan fatty acid ester, sucrose fatty acid ester and alkylphenol ethoxylate.

14. The method of claim 13, wherein the ratio of the volume of the aqueous phase to the weight of the oil phase is 10ml to 40ml:1g.

15. The method according to any one of claims 1 to 4, wherein the aqueous phase in step 2) comprises:

a) 0.5-15% by weight, based on the weight of the aqueous phase, of a water-soluble electrolyte which is a water-soluble inorganic salt;

b) And the water-soluble or oil-soluble initiator accounts for 1-10% of the total weight of the monomer components based on the total weight of the monomer components of the oil phase.

16. The method of claim 15, wherein the water-soluble inorganic salt is selected from monovalent, divalent inorganic salts of alkali and alkali metal halides or sulfates.

17. The method of claim 15, wherein the initiator is selected from any one of a photoinitiator, persulfate, azobisis Ding Mi hydrochloride, or a redox initiation system.

18. The method of claim 17, wherein the photoinitiator is selected from at least any one of diphenyl ketone, α -hydroxyacetophenone, benzyl ketal, α -aminoalkylbenzophenone, or acylphosphine oxide; the persulfates, azo diiso Ding Mi hydrochloride or redox initiation system is at least one selected from sodium persulfate, ammonium persulfate, potassium persulfate, azo diisobutyl imi dihydrochloride, azo diiso Ding Mi hydrochloride or persulfate-sodium hydrogen sulfite, persulfate-ascorbic acid and persulfate-sodium thiosulfate.

19. The method of claim 15, wherein the aqueous phase of step 2) is added to the oil phase under shear at an emulsification temperature of 40 ℃ to 90 ℃ and a mixing shear rate of 100rpm to 2000rpm to form a stable water-in-oil emulsion.

20. The method according to any one of claims 1 to 4, wherein the high internal phase Pickering emulsion formed in step 3) is put into an oven, water bath or hot steam for curing at a temperature of 40-120 ℃ for a time of not more than 0.5 hours, and the residual monomer content of the foam after curing is less than 500ppm based on the weight of the polymer.

21. A bacteriostatic foam absorbent material obtainable by the process of any one of claims 1 to 20.

22. The bacteriostatic foam absorbent material according to claim 21, wherein the contact angle of the bacteriostatic foam absorbent material to physiological saline is less than 100 ℃ and the reverse osmosis amount is less than 0.2 g.

23. The bacteriostatic foam absorbent material according to claim 22, wherein the glass transition temperature of the bacteriostatic foam absorbent material is-30 ℃ -30 ℃, and the cell number average diameter is 10-150 μm.

24. The bacteriostatic foam absorbent material according to any one of claims 21-23, wherein the bacteriostatic foam absorbent material has a bacteriostatic activity of more than 70% against escherichia coli, staphylococcus aureus and candida albicans after 1 hour of antimicrobial testing.

25. Use of a bacteriostatic foam absorbent material according to any one of claims 1-20 or a bacteriostatic foam absorbent material according to any one of claims 21-24 in disposable hygiene products.

26. Use of the bacteriostatic foam absorbent material according to claim 25 for feminine sanitary napkins, baby diapers, adult incontinence products, pet pads or disposable medical hygiene products.