CA1209524A - Hydrophilic interpolymers of acrylic acid and acrylate - Google Patents
Hydrophilic interpolymers of acrylic acid and acrylateInfo
- Publication number
- CA1209524A CA1209524A CA000379531A CA379531A CA1209524A CA 1209524 A CA1209524 A CA 1209524A CA 000379531 A CA000379531 A CA 000379531A CA 379531 A CA379531 A CA 379531A CA 1209524 A CA1209524 A CA 1209524A
- Authority
- CA
- Canada
- Prior art keywords
- film
- weight percent
- acrylate
- comonomer
- methacrylate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/04—Acids; Metal salts or ammonium salts thereof
- C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
- C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
- C08F20/10—Esters
- C08F20/12—Esters of monohydric alcohols or phenols
- C08F20/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
- C08F20/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
- A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
- A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
- A61L15/42—Use of materials characterised by their function or physical properties
- A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
Abstract
ABSTRACT OF THE DISCLOSURE
Highly water absorbent polymers are obtained by polymerizing 65 to 95 weight percent of acrylic acid and 5 to 35 weight percent of a comonomer selected from an alkyl or a cyclohexyl methacrylate, phenyl acrylate, phenoxyalkyl acrylate and dialkylaminoalkyl acrylate or methacrylate. The polymerization can be carried out in the presence of a free radical catalyst in which case the polymer is then preferably neutralized with a base. Alternatively, carboxylic groups are neutralized first and then polymerized by subjecting the monomer mixture either to radiation or to UV light.
Highly water absorbent polymers are obtained by polymerizing 65 to 95 weight percent of acrylic acid and 5 to 35 weight percent of a comonomer selected from an alkyl or a cyclohexyl methacrylate, phenyl acrylate, phenoxyalkyl acrylate and dialkylaminoalkyl acrylate or methacrylate. The polymerization can be carried out in the presence of a free radical catalyst in which case the polymer is then preferably neutralized with a base. Alternatively, carboxylic groups are neutralized first and then polymerized by subjecting the monomer mixture either to radiation or to UV light.
Description
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This invention relates to polymeric films based on acrylic acid and an acrylate.
A variety of hydrophilic polymers which are useful in the manufacture of water absorbent films and fibers have been reported in the prior art. U.S. Patent 3,915,921 dis~
closes copolymers of unsaturated carboxylic acid monomers with alkyl acrylate esters wherein the alkyl group contains 10 to 30 carbon atoms. However, because of the high Tg of these polymeric materials, it is difficult to extrude them in fiber or film form. Furthermore, films pressed from the powders require high temperatures, the films are brittle and fragile, and have a reduced initial rate of water absorption.
U.S. Patènt 4,062,817 discloses polymers of un-saturated copolymerizable carboxylic acids, at least one alkyl acrylate or methacrylate wherein the alkyl group has 10 to 30 carbon atoms and another alkyl acrylate or methacrylate wherein the alkyl group has 1 to 8 carbons. This composition alleviated many of the deficiencies of the earlier compositions.
Further improvements in the hydrophilic properties were obtained by compositions disclosed in U.S. Patent 4,066,583. This Patent discloses a composition comprising (1) a copolymer of the type disclosed in the '817 patent, except that after copolymerization 30 to ~0 percent of the carboxylic groups were neutralized with an alkali metal or ammonia and (2) an aliphatic glycol, a plasticizer which is important in facilitating extrusion of the polymer.
Most recently, U.S. Patent 4,167,464 discloses highly water absorbent polymers obtained by photopolymerizing an alkaline metal salt of acrylic acid, a long chain alkyl acrylate or methacrylate and a short chain alkyl acrylate or methacrylate in the presence of a photoinitiator.
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In accordance with the invention there is provided a water insoluble, flexible~ highly water absorbent polyMeric film having up to 25 mil thickness and containing water, said film being prepared by photopolymerizing a monomer mixture consisting of: (a) 65 to 95 weight percent of acrylic acid, 60 to 100 percent of the carboxylic groups having been neutralized with an alkali metal hydroxide or ammonia base prior to polymerization, (b) 5 to 35 weight percent of a co-monomer selected from the group consisting of 2-hydroxyethyl methacrylate and dialkylaminoalkyl acrylate or methacrylate wherein each alkyl of the dialkyl groups has 1 to 8 carbons and the other alkyl group has 2 to 6 carbons, (c) 0.01 to 5 weight percent, based on the total weight of the monomers, of a photoinitiator, (d) 0 to 5 weight percent3 based on the weight of the monomers, of a cross-linking agent which contains two or more ethylenic unsaturations, and (e) a sufficient amount of water to render the resulting film flexible.
The aqueous monomer mixture can be spread to the desired thickness and then polymerized by exposure to a UV light or radiation sources. If photopolymerized, a photoinitiator must be employed.
The film of the invention has outstanding absorption and retention properties of water and ionic solutions such as urine or blood.
~,i'"'`l Suitably about 70 to 100, preferably 80 to 100 percent of the carboxylic groups of the acrylic acid have been neutralized prior to polymerization.
Examples of dialkylaminoalkyl acry~ates and methacrylates are dimethylaminoethyl acrylate, which is preferred, dimethylaminobutyl acrylate, dimethylaminohexyl acrylate, diethylamiroethyl acrylate, diethylaminobutyl acrylate, dipropylaminohexyl acrylate, dipropylaminopropyl acrylate, dibutylaminoethyl acrylate, dibutylaminobutyl acrylate, .. ..
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dibutylaminohexyl acrylate, di-n-hexylaminoethyl acry-late, di-n-octylaminoethyl acrylate, di-n~oc~ylamino-butyl acrylate, dimethylaminoethyl methacrylate, di-methylaminobutyl methacrylate, dimethylaminohexyl meth-acrylate, diethylaminoethyl methacrylate, die~hylamino-butyl methacrylate, di-n-octylaminohexyl me~hacrylate and the like.
In addition to the above discussed monomers from which the copolymers of this invention are prepared, minor amounts,that is less than 5 weight percent,of additional monomers may also be used. Whether these additional monomers are employed will depend on the end use and the physical properties required, that is, the speed and degree of absorption and the tear strength needed for the film or fabric. Such additional monomers are discussed below.
One type of such additional monomers are ~
olefinically unsaturated nitriles,preferably the mono-olefinically unsaturated nitriles,having from 3 to 10 carbon atoms such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like. Most preferred nitriles are acrylonitriles and methacrylonitrile.
~ nother useful class of additional monomers which may be incorporated in the interpolymers of this invention is monoethylenically unsaturated amides which have at least one hydrogen on the amide nitrcgen and the olefinic unsaturation is alpha,beta to the carbonyl group.
The preferred amides have the structure CH2=C--C-NH-R4 wherein R3 is a member o the group conslsting of hydro-gen and an alkyl group having from l to 4 carbon atoms and R4 is a member of the group consisting of hydrogen and an alkyl group having from 1 to 6 carbon atoms.
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Representative amides include acrylamide, methacryla-mide, N-methy~ acrylamide, N~t-hutyl acrylamide, N-cyclohexyl acrylamide, N-ethyl acrylamide and others.
Of the amides most preferred are acrylamide and meth-5 acrylamide.
Other acrylic amides include N-alkylol am~des of alpha,beta-olefinically unsaturated carboxylic acids including those having from 4 to 10 carbon atoms such as N-methylol acrylamide, N-ethanol acrylamide, N-pro-10 panol acrylamide, and the like. The preferred monomersof the N-alkylol amide type are the N-alkylol amides of alpha,beta-monoolefinically unsaturated monocarboxylic acids and the most preferred is N-methylol acrylamide.
Also useful are N-alkoxymethyl acrylamides 15 which have the structure ~ I
CH =~- -N-C~2-O-R6 whexein R5 is selected from the group consisting of hydrogen and methyl, and R6 is an alkyl group having from 1 to a carbon atoms. It is thus intPnded that 20 where references axe made herein regarding the essential N-substituted alkoxymethyl amides, the term "acrylamide"
includes 'Imethacrylamide'~ within its meaning. The preferred alkoxymethyl acrylamides are those wherein R~
is an alkyl group containing from 2 to 5 carbon atoms, 25 and especially useful is N-butoxymethyl acrylamide.
The above discussed monomers can be copoly-merized by subjecting the monomer mixture to UV light.
If a film is desired the monomer can be spread on a surface to the desired thickness, e.g. 1 mil to 25 mil, 30 and then subjected to UV light for a short time, e.g.one second to several minutes. The actual length of ir-radiation will depend on a number of factors, such as ~l2~$5~
the thickness o~ the monome~ film, the distance from and the intensity of the source of irradiation, the specific monomers employed and the ratio o~ such mono-mers to each other, the presence or absence ofadditional comonomers and the nature and the amount of the photo-initiator employed. The type o~ photoinitiator employed will depend at least in part on the type of UV irradia-tion employed (particularly its wave length) since various photoinitiators may be decomposed by W light of different wavelengths. If it is desired that the material be in the form of fibers, the monomer mixture can be thickened and then spun in~o fibers whichl upon exposure to W light, are polymeriæed.
In order to effect quic~ and efficient poly-merization under UV li~ht, 0.01 to 5 weight percent of a photoinitiator, preferably 0.1 to 5 percent and more preferably 0.3 to 1.0 weight percent, must be incorpor-ated into the monomer mixture. ~ny compound which dissociates into free radicals when exposed to UV
radiation can be employed. There are many known photo-initiator~ or photosensitizers such as acetophenone, propiophenone, benzophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3- or 4-methylacetophenone r 3- or 4-penty-lacetophenone, 3- or 4-methoxyacetophenone, 3- or 4-bromoacetophenone, 3- or 4-allylacetophenone, p-di-acetylbenzene, 3- or 4-methoxybenzophenone, 3- or 4-methylbenzophenone, 3- or 4-chlorobenzophenone, 4,4-dimethoxybenzophenone, 4-chloro-4' benzylbenzophenone, 3-chloroxanthone, 3,9-dichloroxanthone, 3-chloro~8-nonyl-xanthone, 3 methoxyxanthone, 3-iodo~7-methoxy xanthone, 2,2-dimethox~acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2,2-dibutoxyacetophenone, 2,2-dihexoxyacetophenone, 2,2-di(2-ethylhexoxy) acetophenone, 2,2-diphenoxyacetophen--5~
one, benzoin, methyl benzoin ether, ethyl bezoin ether, isopropyl benzoin ether, bu.tyl benzsin ether, isobutyl benzoin ether, benzoin acetate, benzoin phenyl carbamate, ~ diethoxyacetophenone, ~,a-diethoxy-a-phenyl-aceto~
phenone, ~u-dimethoxy-a-phenylacetophenone~ 4,4 -dicarboethoxybenzoin ethyl ether, ~-chloroacetophenone, ~-bromoacetophenone, benzoin phenyl ether, a-methylben~
zoin ethyl ether, benzoin acrylate, ~-methylolbenzoin methyl ether, ~ trichIoroacetophenone, o-bromoaceto-phenone, 4-(benzoylphenylmethoxycarbonylimino)-2-(acrylyloxyethoxycarbonylimino)-l-methylbenzene, cumene . hydroperoxide t benzoyl peroxide, dicumyl peroxide, tert-butyl perbenzoate, ~,~-azobisisobutyronitrile, phenyl disulfide, chloromethylbenzanthrone, chloromethylanthra-quinine, chloromethylnaphthalene, bromomethylbenzan-throne, bromomethylanthraquinone, bromomekhylnaphthalene, and the like, and mixtures thereof.
In addition to the photoinitiator it may be advantageous to employ also from 0.3 to 5.0 percent of an activator. Illustrative examples of such activators are mercaptoacetic acid, mercaptoethanol, or organic amines such as methylamine, decylamine, diisopropylamine, tri-butylamine, tri-2-chloroethylamine, ethanolamine, ~ri-ethanolamine, methyldiethanolamine, 2-aminoethylethanol-~5 amine, allylamine, cyclohexylamine, cyclopentadienyl-amine, diphenylamine, ditolylamine, trixylylamine, tri-benzylamine, N-cyclohexylethyleneimine, piperidine, 2-methylpiperidine, N-ethylpiperidine, 1,2,3,4-tetrahydro-pyridine, 2- or 3- or 4-picoline, morpholine,N-methylmo~
pholine, piperazine, N-methylpiperazine, 2,2-dimethyl-1,3-bis-[3~(N-morpholinyl)propionyloxy]-propane, 1,5-bis [3-(N-morpholinyl)propionyloxy]di-ethyl ether, and the like.
The monomer mixtures are prepared as aqueous dispersions which eliminates the need for organic sol-vents. Thisavoids the pollutionproblems caused by the ~z~ s;~
removal of organic solvents or the cost associated with the removal of the pollutants. In order to obtain a stable homogeneous dispersion of the monomers, it is preferred that the aqueous dispersions contain 0.01 to 5 5%, and preerably 0.1 to 1%, of a surface active agent such as an anionic, amphoteric, or nonionic dispersing agent or a mixture of dispersants. Useful anionic dis-persing agents include alkali metal or ammonium salts of the sulfates of alcohols having from 8 to 18 carbon atoms such as sodium lauryl sulfate; ethanolamine lauryl sul-fate, ethylamine lauryl sulfate~ alkali metal and am-moni~um salts of sulfonated petroleum and paraffin oils;
sodium salts of aromatic sulfonic acids such as dodecane-l-sulfonic acid and octadecane-l-sulfonic acid; aralkyl sulfonates such as sodium isopropyl benzene sulfonate, sodium dodecyl benzene sulfonate and sodium isobutyl naphthalene sulfonate; alkali metal and ammonium salts of sulfonated dicarboxylic acid esters such as sodium dioctyl sulfosuccinate, disodium-n-octadecyl sulfosuc-20 cinate; alkali metal or ammonium salts of free acid ofcomplex organic mo~o-and diphosphate esters, sulfosuc-cinic acid derivatives (AEROSO~ dispersants), organic phosphate esters (GAFACXdispersants~ and the like.
Nonionic dispersants such as octyl-or nonylphenyl poly-ethoxyethanol as well as the PLURONIC*and the TRITO~dispersants may also be used. Also useful are ampho-teric dispersants such as dicarboxylic coconut deriva-tives (MIRANOL~. Further examples of useful dispersants are those disclosed beginning on page 102 in J. Van Alphen's "Rubber Chemicals",Elsevier Publishing Co.,1956.
The monomer mixture can also ba polymerized withr out first neutralizing the carboxylic groups. The poly-merization can be carried out in an inert diluent having some solubilizïng action on one or more of the monomeric ingredients but substantially none on the resultant poly-~r mer. Polymerization in mass may be employed but is not * trade mark _ 9 _ preferred because of the difficlllty in working up thesolid polymeric masses obtained. Polymerization in an aqueous medium containing a water-soluble free radical catalyst peroxyyen is useful. Polymexization in an organic liquid which i5 a solvent for the monomers but a non-solvent for the polymer, or in a mixture of such solvents, in the presence of a solvent-soluble catalyst is more preferred because khe product is usually obtained as a very fine friable and often fluffy precipitate which~ after solvent removal, seldom requires grinding or other treatment before use, The polymerizations pre-ferably are conducted in the presence o~ a haloethane or halomethane containing at least four halogen atomsO
Representative materials include for example, a fluoro-ethane, fluoromethane, chlorofluoromethane, bromofluoro-ethane~ or preferably a chlorofluoroethane or chloro-fluoromethane containing at least four halogen atoms.
Polymers obtained from free radical polymer-izations generally do not attain their maximum proper-ties until converted to a partial alkali, ammonium oramine salt. The neutralizing agent is preferably a monovalent alkali such as sodium, potassium, lithium or ammonium hydroxide or the carbonates and bicarbonates thereof, or mixtures of the same, and also amine bases ~5 having not more than one primary or secondary amino group. Such amines include, for example, triethanol-amine, ethanolamine, isopropanolamine, triethylamine, trimethylamine, and the like.
The procedures to be employed in free radical pol~merizations of such monomers, neutralization of the resulting polymers and their work up is disclosed in greater detail in U.S. Patent 4,062,817.
~ lthough cross-linking agents are not rPquired to obtain useful, highly absorbent composi-i tions o this invention, it may be desirable toincorporate a cross-linking agent since films prepared from compositions containing a cross-linking agent tend to have greater gel strength and an improved ability for the copolymers to swell under a confining pressure. Cross-linking agents may be used in the concentration of about 0.01 to about 50% by weight based on the total weight o the monomers, and preferably about 0.1 to about 5%.
Useful cross-linking monomers are polyalkenyl polyethers having more than one alkenyl ether grouping per molecule or monomers which contain two to six ethylenically unsaturatedgroups such as allyl, acrylate, or vinyl groups. The most useul possess alkenyl groups in which an olefinic double bond is attached to a terminal methylene group, CH2=C ~ . Other cross-linking monomers include, for example diallyl esters or ethers, allyl or methallyl acrylates and acrylamides, diacrylates and dimethacrylates, divinyl compounds and the like. Illustrative examples o polyfunctional cross linking agents are polyethyleneglycol diacrylate and dimethacrylate, ethylene glycol dimethacrylate, tetraethyleneglycol diacrylate, 1,3-butyleneglycol di-methacrylate, diethyleneglycol divinyl ether, trimethy-lolpropane diallyl ether~ divinyl benzene, trimethy-lolpropane triacrylate, trimethylolpropane trimethacry-late, triallyl cyanurate, pentaerythritol triacrylate, diallyl itaconate, methylene bis(acrylamide), allyl pentaerithritol, allyl sucrose, 1,6-hexanediol diacry-late, tetramethylene glycol diacrylate and dimethacry-late, ethylene glycol diacrylate and dimethacrylate, triethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, diallyl itaconates and the like.
As discussed above, the interpolymers of 5 this invention can be photopolymerized. Additionally, ~.2~ 5~ -these interpolymers can be obtained by radiation poly-merization by subjecting said monomers to electron beam radiation of sufficient intensity to cause said monomers to polymerize substantially completely. The amount and the intensity of radiation required will depend on the thickness of the film, the specific monomers employed, and the speed and the degree of polymerization desired.
Generally, for the applications for which the resulting polymers are especially useful films, sheets or fibers in the range from 0.5 to 5 mils are most desirable.
Therefore, relati~ely low intensity electron beam sources, generally less than 200 K~, would be sufficient to effect polymerization. Generally for the type of monomer systems employed in this invention from 1 to 15 M rads of radiation is required. However, it should be pointed out that the amount and intensity of radi-ation must be optimized for each system taking all variables into consideration, i.e., the monomers employed, the thickness of the film, the desired speed of polymerization, the desired degree of polymerization and the rate of radiation.
When employing photopolymerization or radia-tion polymerization methods, the polymers of this inven-tion can be polymerized in a film or a fiber form. The resulting film or fiber is an elastic, flexible material that has an appreciable degree of strength.
If a fine, flaky form is desired, the film can be con-verted to such a form by drying and then pulverizing or grindiny it in standard equipment.
As water absorbent materials these polymers find many uses in film, fiber, abric and similar forms.
They are of particular utility in the disposable non-wo~en industry where there is need for polymers which will absorb and retain watar and ionic physioLogical fluids. An important feature of these polymers is their 5Z~
enhanced thickening property even in the presence of a salt. Specific applications include disposable diapers, medical-surgical supplies and personal care products.
Such applications require a polymer which must imbibe the liquid to be absor~ed rapidly and be a polymer that will not dissolve. Further, the fluid must be immobil-ized or congealed in some way to be retained. The materials may also be used as suitable additives to greatly increase the absorptive power of conventional absorbents such as cotton, wood pulp and other cellu-losic absor~ents used in applications such as wiping cloths, surgical sponges, catamenial devices, and the like. In a specific application, for example, a dis-posable diaper, there i5 an inner layer of a soft absorbent nonwoven material that absorbs and passes urine to an inner layer of fluffy fibrous absorbent material, wherein during the construction of this non-woven fiber agglomerates or fibers of the polymers of this invention may be included and an additional imper-vious plastic layer, as polyethylene. A film of thecopolymers of this invention may be used between the outer plastic layer and the inner fluffy absorbent layer. Use of the polymers of this invention can result in reduction in the bulk size of many disposable non-~5 wovens.
The instant copolymers can also be used asflocculants in water treatment, in metallurgical pro-cesses, in ore beneficiation and flotation, in agricul-tural applications such as in soil treatment or seed coating or in any applications where the inherent properties of the polymer are desirable, such as its thickening property in an aqueous medium.
To prepare the cured copolymers of this inven-tion, the monomers, a dispersant and a photoinitiator, lf used, are mixed in a vessel. Then either a film or ~2'.P~S~
~ibers are produced from the monomer mixture which, upon exposure to UV light or radiation, are rapidly polymerized. The various steps in the procedure are described in greater detail below.
Monomer Mixture Preparation: The monomer mixture can ~e prepared by following one of two simple procedures. One method is to dissolve a previously prepared and dried alkali metal or ammonium salt of acrylic acid in water to which is then added a disper-sant. To the aqueous solution is then added the acxy-late or the methacrylate es~er which already contains a photoinitiator if one is employed. Another method is to prepare the acrylic acid salt in situ by adding acrylic acid to the proper amount of cold aqueous base ~e.g. KOH, NaOH or NH40H~ with cooling. To the aqueous solution is then added a mixture of the acrylate or the methacrylate ester to which, if required, a photo-initiator was previously added; the dispersant is added last.
Film Preparation: The aqueous monomer dis-persion is spread to a desired thickness (e.g. by the use of Boston-Bradley adjustable blade, by spraying or other known means~ on a suitable substrate (e.g. Mylar, polyethylene, paper, etc.). The liquid film is then exposed to a UV or radiation source which polymerizes the monomer mixture into a soft, pliable form. Ir desired, this film can be dried in an oven at about 50 C for l to 15 min. After drying the film may still retain some flexibility or become bri-ttle and flaky, depending on the length of drying.
Fiber Preparation: The aqueous monomer dis-persion is thickened to the desired degree with a non-reactive thickening agent such as a cellulose derivative as, for example, hydroxypropyl cellulose, high molecu-lar weight polyvinyl pyrrolidone and the like; natural ~2~S~
- i4 -gums such as guar gum, locust bean gum, gum trayacanth;
agar, naturally occuring hydrocolloids such as alginates and the like. Fibers are then spun froma spinneret in a regular manner and immediately exposed to a W or radiation source.
To further illustrate the present invention the following examples are presented. The copolymers and the films were prepared according to the procedures described above. The copolymers of Examples 1 to 9, 10 presented in Table I, have been photopolymerized using QC 1202 Processor manufactured ~y Radiation Polymer Co.
(with belt speed of 0 to 1000 ft/min 304.8 m/min) having
This invention relates to polymeric films based on acrylic acid and an acrylate.
A variety of hydrophilic polymers which are useful in the manufacture of water absorbent films and fibers have been reported in the prior art. U.S. Patent 3,915,921 dis~
closes copolymers of unsaturated carboxylic acid monomers with alkyl acrylate esters wherein the alkyl group contains 10 to 30 carbon atoms. However, because of the high Tg of these polymeric materials, it is difficult to extrude them in fiber or film form. Furthermore, films pressed from the powders require high temperatures, the films are brittle and fragile, and have a reduced initial rate of water absorption.
U.S. Patènt 4,062,817 discloses polymers of un-saturated copolymerizable carboxylic acids, at least one alkyl acrylate or methacrylate wherein the alkyl group has 10 to 30 carbon atoms and another alkyl acrylate or methacrylate wherein the alkyl group has 1 to 8 carbons. This composition alleviated many of the deficiencies of the earlier compositions.
Further improvements in the hydrophilic properties were obtained by compositions disclosed in U.S. Patent 4,066,583. This Patent discloses a composition comprising (1) a copolymer of the type disclosed in the '817 patent, except that after copolymerization 30 to ~0 percent of the carboxylic groups were neutralized with an alkali metal or ammonia and (2) an aliphatic glycol, a plasticizer which is important in facilitating extrusion of the polymer.
Most recently, U.S. Patent 4,167,464 discloses highly water absorbent polymers obtained by photopolymerizing an alkaline metal salt of acrylic acid, a long chain alkyl acrylate or methacrylate and a short chain alkyl acrylate or methacrylate in the presence of a photoinitiator.
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In accordance with the invention there is provided a water insoluble, flexible~ highly water absorbent polyMeric film having up to 25 mil thickness and containing water, said film being prepared by photopolymerizing a monomer mixture consisting of: (a) 65 to 95 weight percent of acrylic acid, 60 to 100 percent of the carboxylic groups having been neutralized with an alkali metal hydroxide or ammonia base prior to polymerization, (b) 5 to 35 weight percent of a co-monomer selected from the group consisting of 2-hydroxyethyl methacrylate and dialkylaminoalkyl acrylate or methacrylate wherein each alkyl of the dialkyl groups has 1 to 8 carbons and the other alkyl group has 2 to 6 carbons, (c) 0.01 to 5 weight percent, based on the total weight of the monomers, of a photoinitiator, (d) 0 to 5 weight percent3 based on the weight of the monomers, of a cross-linking agent which contains two or more ethylenic unsaturations, and (e) a sufficient amount of water to render the resulting film flexible.
The aqueous monomer mixture can be spread to the desired thickness and then polymerized by exposure to a UV light or radiation sources. If photopolymerized, a photoinitiator must be employed.
The film of the invention has outstanding absorption and retention properties of water and ionic solutions such as urine or blood.
~,i'"'`l Suitably about 70 to 100, preferably 80 to 100 percent of the carboxylic groups of the acrylic acid have been neutralized prior to polymerization.
Examples of dialkylaminoalkyl acry~ates and methacrylates are dimethylaminoethyl acrylate, which is preferred, dimethylaminobutyl acrylate, dimethylaminohexyl acrylate, diethylamiroethyl acrylate, diethylaminobutyl acrylate, dipropylaminohexyl acrylate, dipropylaminopropyl acrylate, dibutylaminoethyl acrylate, dibutylaminobutyl acrylate, .. ..
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dibutylaminohexyl acrylate, di-n-hexylaminoethyl acry-late, di-n-octylaminoethyl acrylate, di-n~oc~ylamino-butyl acrylate, dimethylaminoethyl methacrylate, di-methylaminobutyl methacrylate, dimethylaminohexyl meth-acrylate, diethylaminoethyl methacrylate, die~hylamino-butyl methacrylate, di-n-octylaminohexyl me~hacrylate and the like.
In addition to the above discussed monomers from which the copolymers of this invention are prepared, minor amounts,that is less than 5 weight percent,of additional monomers may also be used. Whether these additional monomers are employed will depend on the end use and the physical properties required, that is, the speed and degree of absorption and the tear strength needed for the film or fabric. Such additional monomers are discussed below.
One type of such additional monomers are ~
olefinically unsaturated nitriles,preferably the mono-olefinically unsaturated nitriles,having from 3 to 10 carbon atoms such as acrylonitrile, methacrylonitrile, ethacrylonitrile, and the like. Most preferred nitriles are acrylonitriles and methacrylonitrile.
~ nother useful class of additional monomers which may be incorporated in the interpolymers of this invention is monoethylenically unsaturated amides which have at least one hydrogen on the amide nitrcgen and the olefinic unsaturation is alpha,beta to the carbonyl group.
The preferred amides have the structure CH2=C--C-NH-R4 wherein R3 is a member o the group conslsting of hydro-gen and an alkyl group having from l to 4 carbon atoms and R4 is a member of the group consisting of hydrogen and an alkyl group having from 1 to 6 carbon atoms.
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Representative amides include acrylamide, methacryla-mide, N-methy~ acrylamide, N~t-hutyl acrylamide, N-cyclohexyl acrylamide, N-ethyl acrylamide and others.
Of the amides most preferred are acrylamide and meth-5 acrylamide.
Other acrylic amides include N-alkylol am~des of alpha,beta-olefinically unsaturated carboxylic acids including those having from 4 to 10 carbon atoms such as N-methylol acrylamide, N-ethanol acrylamide, N-pro-10 panol acrylamide, and the like. The preferred monomersof the N-alkylol amide type are the N-alkylol amides of alpha,beta-monoolefinically unsaturated monocarboxylic acids and the most preferred is N-methylol acrylamide.
Also useful are N-alkoxymethyl acrylamides 15 which have the structure ~ I
CH =~- -N-C~2-O-R6 whexein R5 is selected from the group consisting of hydrogen and methyl, and R6 is an alkyl group having from 1 to a carbon atoms. It is thus intPnded that 20 where references axe made herein regarding the essential N-substituted alkoxymethyl amides, the term "acrylamide"
includes 'Imethacrylamide'~ within its meaning. The preferred alkoxymethyl acrylamides are those wherein R~
is an alkyl group containing from 2 to 5 carbon atoms, 25 and especially useful is N-butoxymethyl acrylamide.
The above discussed monomers can be copoly-merized by subjecting the monomer mixture to UV light.
If a film is desired the monomer can be spread on a surface to the desired thickness, e.g. 1 mil to 25 mil, 30 and then subjected to UV light for a short time, e.g.one second to several minutes. The actual length of ir-radiation will depend on a number of factors, such as ~l2~$5~
the thickness o~ the monome~ film, the distance from and the intensity of the source of irradiation, the specific monomers employed and the ratio o~ such mono-mers to each other, the presence or absence ofadditional comonomers and the nature and the amount of the photo-initiator employed. The type o~ photoinitiator employed will depend at least in part on the type of UV irradia-tion employed (particularly its wave length) since various photoinitiators may be decomposed by W light of different wavelengths. If it is desired that the material be in the form of fibers, the monomer mixture can be thickened and then spun in~o fibers whichl upon exposure to W light, are polymeriæed.
In order to effect quic~ and efficient poly-merization under UV li~ht, 0.01 to 5 weight percent of a photoinitiator, preferably 0.1 to 5 percent and more preferably 0.3 to 1.0 weight percent, must be incorpor-ated into the monomer mixture. ~ny compound which dissociates into free radicals when exposed to UV
radiation can be employed. There are many known photo-initiator~ or photosensitizers such as acetophenone, propiophenone, benzophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3- or 4-methylacetophenone r 3- or 4-penty-lacetophenone, 3- or 4-methoxyacetophenone, 3- or 4-bromoacetophenone, 3- or 4-allylacetophenone, p-di-acetylbenzene, 3- or 4-methoxybenzophenone, 3- or 4-methylbenzophenone, 3- or 4-chlorobenzophenone, 4,4-dimethoxybenzophenone, 4-chloro-4' benzylbenzophenone, 3-chloroxanthone, 3,9-dichloroxanthone, 3-chloro~8-nonyl-xanthone, 3 methoxyxanthone, 3-iodo~7-methoxy xanthone, 2,2-dimethox~acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2,2-dibutoxyacetophenone, 2,2-dihexoxyacetophenone, 2,2-di(2-ethylhexoxy) acetophenone, 2,2-diphenoxyacetophen--5~
one, benzoin, methyl benzoin ether, ethyl bezoin ether, isopropyl benzoin ether, bu.tyl benzsin ether, isobutyl benzoin ether, benzoin acetate, benzoin phenyl carbamate, ~ diethoxyacetophenone, ~,a-diethoxy-a-phenyl-aceto~
phenone, ~u-dimethoxy-a-phenylacetophenone~ 4,4 -dicarboethoxybenzoin ethyl ether, ~-chloroacetophenone, ~-bromoacetophenone, benzoin phenyl ether, a-methylben~
zoin ethyl ether, benzoin acrylate, ~-methylolbenzoin methyl ether, ~ trichIoroacetophenone, o-bromoaceto-phenone, 4-(benzoylphenylmethoxycarbonylimino)-2-(acrylyloxyethoxycarbonylimino)-l-methylbenzene, cumene . hydroperoxide t benzoyl peroxide, dicumyl peroxide, tert-butyl perbenzoate, ~,~-azobisisobutyronitrile, phenyl disulfide, chloromethylbenzanthrone, chloromethylanthra-quinine, chloromethylnaphthalene, bromomethylbenzan-throne, bromomethylanthraquinone, bromomekhylnaphthalene, and the like, and mixtures thereof.
In addition to the photoinitiator it may be advantageous to employ also from 0.3 to 5.0 percent of an activator. Illustrative examples of such activators are mercaptoacetic acid, mercaptoethanol, or organic amines such as methylamine, decylamine, diisopropylamine, tri-butylamine, tri-2-chloroethylamine, ethanolamine, ~ri-ethanolamine, methyldiethanolamine, 2-aminoethylethanol-~5 amine, allylamine, cyclohexylamine, cyclopentadienyl-amine, diphenylamine, ditolylamine, trixylylamine, tri-benzylamine, N-cyclohexylethyleneimine, piperidine, 2-methylpiperidine, N-ethylpiperidine, 1,2,3,4-tetrahydro-pyridine, 2- or 3- or 4-picoline, morpholine,N-methylmo~
pholine, piperazine, N-methylpiperazine, 2,2-dimethyl-1,3-bis-[3~(N-morpholinyl)propionyloxy]-propane, 1,5-bis [3-(N-morpholinyl)propionyloxy]di-ethyl ether, and the like.
The monomer mixtures are prepared as aqueous dispersions which eliminates the need for organic sol-vents. Thisavoids the pollutionproblems caused by the ~z~ s;~
removal of organic solvents or the cost associated with the removal of the pollutants. In order to obtain a stable homogeneous dispersion of the monomers, it is preferred that the aqueous dispersions contain 0.01 to 5 5%, and preerably 0.1 to 1%, of a surface active agent such as an anionic, amphoteric, or nonionic dispersing agent or a mixture of dispersants. Useful anionic dis-persing agents include alkali metal or ammonium salts of the sulfates of alcohols having from 8 to 18 carbon atoms such as sodium lauryl sulfate; ethanolamine lauryl sul-fate, ethylamine lauryl sulfate~ alkali metal and am-moni~um salts of sulfonated petroleum and paraffin oils;
sodium salts of aromatic sulfonic acids such as dodecane-l-sulfonic acid and octadecane-l-sulfonic acid; aralkyl sulfonates such as sodium isopropyl benzene sulfonate, sodium dodecyl benzene sulfonate and sodium isobutyl naphthalene sulfonate; alkali metal and ammonium salts of sulfonated dicarboxylic acid esters such as sodium dioctyl sulfosuccinate, disodium-n-octadecyl sulfosuc-20 cinate; alkali metal or ammonium salts of free acid ofcomplex organic mo~o-and diphosphate esters, sulfosuc-cinic acid derivatives (AEROSO~ dispersants), organic phosphate esters (GAFACXdispersants~ and the like.
Nonionic dispersants such as octyl-or nonylphenyl poly-ethoxyethanol as well as the PLURONIC*and the TRITO~dispersants may also be used. Also useful are ampho-teric dispersants such as dicarboxylic coconut deriva-tives (MIRANOL~. Further examples of useful dispersants are those disclosed beginning on page 102 in J. Van Alphen's "Rubber Chemicals",Elsevier Publishing Co.,1956.
The monomer mixture can also ba polymerized withr out first neutralizing the carboxylic groups. The poly-merization can be carried out in an inert diluent having some solubilizïng action on one or more of the monomeric ingredients but substantially none on the resultant poly-~r mer. Polymerization in mass may be employed but is not * trade mark _ 9 _ preferred because of the difficlllty in working up thesolid polymeric masses obtained. Polymerization in an aqueous medium containing a water-soluble free radical catalyst peroxyyen is useful. Polymexization in an organic liquid which i5 a solvent for the monomers but a non-solvent for the polymer, or in a mixture of such solvents, in the presence of a solvent-soluble catalyst is more preferred because khe product is usually obtained as a very fine friable and often fluffy precipitate which~ after solvent removal, seldom requires grinding or other treatment before use, The polymerizations pre-ferably are conducted in the presence o~ a haloethane or halomethane containing at least four halogen atomsO
Representative materials include for example, a fluoro-ethane, fluoromethane, chlorofluoromethane, bromofluoro-ethane~ or preferably a chlorofluoroethane or chloro-fluoromethane containing at least four halogen atoms.
Polymers obtained from free radical polymer-izations generally do not attain their maximum proper-ties until converted to a partial alkali, ammonium oramine salt. The neutralizing agent is preferably a monovalent alkali such as sodium, potassium, lithium or ammonium hydroxide or the carbonates and bicarbonates thereof, or mixtures of the same, and also amine bases ~5 having not more than one primary or secondary amino group. Such amines include, for example, triethanol-amine, ethanolamine, isopropanolamine, triethylamine, trimethylamine, and the like.
The procedures to be employed in free radical pol~merizations of such monomers, neutralization of the resulting polymers and their work up is disclosed in greater detail in U.S. Patent 4,062,817.
~ lthough cross-linking agents are not rPquired to obtain useful, highly absorbent composi-i tions o this invention, it may be desirable toincorporate a cross-linking agent since films prepared from compositions containing a cross-linking agent tend to have greater gel strength and an improved ability for the copolymers to swell under a confining pressure. Cross-linking agents may be used in the concentration of about 0.01 to about 50% by weight based on the total weight o the monomers, and preferably about 0.1 to about 5%.
Useful cross-linking monomers are polyalkenyl polyethers having more than one alkenyl ether grouping per molecule or monomers which contain two to six ethylenically unsaturatedgroups such as allyl, acrylate, or vinyl groups. The most useul possess alkenyl groups in which an olefinic double bond is attached to a terminal methylene group, CH2=C ~ . Other cross-linking monomers include, for example diallyl esters or ethers, allyl or methallyl acrylates and acrylamides, diacrylates and dimethacrylates, divinyl compounds and the like. Illustrative examples o polyfunctional cross linking agents are polyethyleneglycol diacrylate and dimethacrylate, ethylene glycol dimethacrylate, tetraethyleneglycol diacrylate, 1,3-butyleneglycol di-methacrylate, diethyleneglycol divinyl ether, trimethy-lolpropane diallyl ether~ divinyl benzene, trimethy-lolpropane triacrylate, trimethylolpropane trimethacry-late, triallyl cyanurate, pentaerythritol triacrylate, diallyl itaconate, methylene bis(acrylamide), allyl pentaerithritol, allyl sucrose, 1,6-hexanediol diacry-late, tetramethylene glycol diacrylate and dimethacry-late, ethylene glycol diacrylate and dimethacrylate, triethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, diallyl itaconates and the like.
As discussed above, the interpolymers of 5 this invention can be photopolymerized. Additionally, ~.2~ 5~ -these interpolymers can be obtained by radiation poly-merization by subjecting said monomers to electron beam radiation of sufficient intensity to cause said monomers to polymerize substantially completely. The amount and the intensity of radiation required will depend on the thickness of the film, the specific monomers employed, and the speed and the degree of polymerization desired.
Generally, for the applications for which the resulting polymers are especially useful films, sheets or fibers in the range from 0.5 to 5 mils are most desirable.
Therefore, relati~ely low intensity electron beam sources, generally less than 200 K~, would be sufficient to effect polymerization. Generally for the type of monomer systems employed in this invention from 1 to 15 M rads of radiation is required. However, it should be pointed out that the amount and intensity of radi-ation must be optimized for each system taking all variables into consideration, i.e., the monomers employed, the thickness of the film, the desired speed of polymerization, the desired degree of polymerization and the rate of radiation.
When employing photopolymerization or radia-tion polymerization methods, the polymers of this inven-tion can be polymerized in a film or a fiber form. The resulting film or fiber is an elastic, flexible material that has an appreciable degree of strength.
If a fine, flaky form is desired, the film can be con-verted to such a form by drying and then pulverizing or grindiny it in standard equipment.
As water absorbent materials these polymers find many uses in film, fiber, abric and similar forms.
They are of particular utility in the disposable non-wo~en industry where there is need for polymers which will absorb and retain watar and ionic physioLogical fluids. An important feature of these polymers is their 5Z~
enhanced thickening property even in the presence of a salt. Specific applications include disposable diapers, medical-surgical supplies and personal care products.
Such applications require a polymer which must imbibe the liquid to be absor~ed rapidly and be a polymer that will not dissolve. Further, the fluid must be immobil-ized or congealed in some way to be retained. The materials may also be used as suitable additives to greatly increase the absorptive power of conventional absorbents such as cotton, wood pulp and other cellu-losic absor~ents used in applications such as wiping cloths, surgical sponges, catamenial devices, and the like. In a specific application, for example, a dis-posable diaper, there i5 an inner layer of a soft absorbent nonwoven material that absorbs and passes urine to an inner layer of fluffy fibrous absorbent material, wherein during the construction of this non-woven fiber agglomerates or fibers of the polymers of this invention may be included and an additional imper-vious plastic layer, as polyethylene. A film of thecopolymers of this invention may be used between the outer plastic layer and the inner fluffy absorbent layer. Use of the polymers of this invention can result in reduction in the bulk size of many disposable non-~5 wovens.
The instant copolymers can also be used asflocculants in water treatment, in metallurgical pro-cesses, in ore beneficiation and flotation, in agricul-tural applications such as in soil treatment or seed coating or in any applications where the inherent properties of the polymer are desirable, such as its thickening property in an aqueous medium.
To prepare the cured copolymers of this inven-tion, the monomers, a dispersant and a photoinitiator, lf used, are mixed in a vessel. Then either a film or ~2'.P~S~
~ibers are produced from the monomer mixture which, upon exposure to UV light or radiation, are rapidly polymerized. The various steps in the procedure are described in greater detail below.
Monomer Mixture Preparation: The monomer mixture can ~e prepared by following one of two simple procedures. One method is to dissolve a previously prepared and dried alkali metal or ammonium salt of acrylic acid in water to which is then added a disper-sant. To the aqueous solution is then added the acxy-late or the methacrylate es~er which already contains a photoinitiator if one is employed. Another method is to prepare the acrylic acid salt in situ by adding acrylic acid to the proper amount of cold aqueous base ~e.g. KOH, NaOH or NH40H~ with cooling. To the aqueous solution is then added a mixture of the acrylate or the methacrylate ester to which, if required, a photo-initiator was previously added; the dispersant is added last.
Film Preparation: The aqueous monomer dis-persion is spread to a desired thickness (e.g. by the use of Boston-Bradley adjustable blade, by spraying or other known means~ on a suitable substrate (e.g. Mylar, polyethylene, paper, etc.). The liquid film is then exposed to a UV or radiation source which polymerizes the monomer mixture into a soft, pliable form. Ir desired, this film can be dried in an oven at about 50 C for l to 15 min. After drying the film may still retain some flexibility or become bri-ttle and flaky, depending on the length of drying.
Fiber Preparation: The aqueous monomer dis-persion is thickened to the desired degree with a non-reactive thickening agent such as a cellulose derivative as, for example, hydroxypropyl cellulose, high molecu-lar weight polyvinyl pyrrolidone and the like; natural ~2~S~
- i4 -gums such as guar gum, locust bean gum, gum trayacanth;
agar, naturally occuring hydrocolloids such as alginates and the like. Fibers are then spun froma spinneret in a regular manner and immediately exposed to a W or radiation source.
To further illustrate the present invention the following examples are presented. The copolymers and the films were prepared according to the procedures described above. The copolymers of Examples 1 to 9, 10 presented in Table I, have been photopolymerized using QC 1202 Processor manufactured ~y Radiation Polymer Co.
(with belt speed of 0 to 1000 ft/min 304.8 m/min) having
2 medium pressure quartz mercury vapor lamps at 200 watts/lineal inch (watts/lineal 2.54 cm.). The distance from the lamps to the film was 15 cm. and the exposure time was 20 sec. at belt speed of 20 ft/min. (6 m/min.).
Comonomers employed in the Examples and identified in Table I by capital letters A to C, are identified below:
A - 2-~ydroxyethyl methacrylate B - Dimethylaminoethyl acrylate C - Mixture of 17.0 g. DMAEA + 1.9 g.
trimethylolpropane triacrylate ~5~ 'r'i ;1 ,:..
5~
, .
~o 9a~J O O cr~ ~\J N
'O ~ C) . . . I
tY~ I LO OJ ~) 0 ~1 ~1 ~7 1 ~ Ll~ 0 ~1 ;~
C
~ O
O ~
~>
~o O
~D ~O O O ~ ~ I a~
I j ~ Ln 0 ~ (D
H H ~ o ~ o o o a~
Q
o o o ~ ~o I "
. ~ r~ i ~ ~ ~ o o :~
u~ 0 ~ ~: X
~ ~ o a>
E
O
u~ ~
~ to a> ~1 X O ^ --~ o Lr O ~1 ~ ~ 5~ ~ ~ ~D
X s~ -- O ~ ~:
~ :~ N r~ o L~ ~ * u~
z ~ ~ ~ S~ O a E3 J ~s:: o v~ ¢ a ,I E ~ 1 0 0 E ~,1 0Q~ , o o c~ v cc H
X ~ E~ Zt~ ~ O ~;~
X~1~ r~ ~ H ~ _ _ *
~2~$.~
Copol~mers having substantially the same properties are obtained when in some of the above compositions potassium hydroxide was employed in place of sodium or ammonium hydroxide, 2,2~diethyoxyaceto-5 phenone in place of IRGACURE~651 and an oligomericsurfactant POLYWET~KX-3 (from Uniroyal) or TRITON N-lll (monophenoxy polyethoxy ethanol) in place of AEROSOL
Al02.
A number of testsare available to determine 10 the absorbency of a material. Following are descrip-tions of the two test procedures which were employed in evaluating absorbency of the interpolymers of this invention.
Static Test (ST) - A weighed film sample is immersed in 15 a test liquid for 10 minutes. It is then removed from the liquid, the excess liquid drained for a few seconds and then shaken lightly several times. The swelled sample is weighed again to determine the weight of liquid absorbed by the polymer.
20 Demand Wettability Test (DWT) - A test diaper is con-structed rom a-4 inch diameter pad (10.16 cm.) using materials from a commercial diaper. A film prepared from a polymer to be tested for absorbency is placed in the center of the test diaper between two layers of 25 fluff (wood pulp?. A diaper without the polymer film is used as a blank. The demand-wettability apparatus is a burette filled with the test fluid and rirmly stoppered at the top, with an air bleed on the side r and a delivery orificeon the bottom connected by a flexible 30 tube to the sample holder. The sample holder has an opening in the center which is connected to the flexible tube that leads to the delivery orifice of the burette.
The sample holder is level with the air ble~d opening in the burette. With this closed-system arrangement 35 the fluid in the flexible tube that comes up to the * trade mark ` ~z~s~
- 17 ,-opening in the sample holder is at zero pressure. Thus when the test diaper is placed on the sample holder over the opening it will absorb the fluid on its own through wicking action. The sample's own absorbent powder will 5 determine the rate and amount of fluid that will be withdrawn from the ~urette. The amount of fluid with-drawn at any given time can be easily read from the burette calibration. An additional feature is that absorbency can be measured against a range of pressures that can be obtained by placing various weights on top of the test diaper. Such pressures are intended to simulate the pressures applied on a diaper in actual use.
This test is described in greater detail by Lichstein, "Demand Wettability, a New Method for 15 Measuring Absorbency Characteristics of Fabrics", Symposium Papers-INDA Technical Symposium, 1974, pp.
129-142.
Compression Test (CT) - This test is a follow up test to the Demand-Wettability Test (DWT). After the sample has 20 absorbed the liquid against a lower pressure in a DWTest, it is removed from the DWT apparatus and placed atop a porous filter funnel. The sample is then subjected to 1.5 psi (0.105 kg/cm ) of pressure for 1 minute and the amount of liquid that is squeezed from the sample is 25 measured. Said pressure corresponds to the maximum pressure that is exertea on portions of a diaper when a toddler is picked up or held. This is 10 to 15 times the pressure that the diaper normally would experience.
The sample is then weighed to determine the amount of fluid in grams retained per one gram of polymer.
In Table II below is presented data comparing the absorbency properties of the copolymer of this invention with two other polymers. The polymer number in the Table corresponds to the example describing the 35 preparation of that specific polymer.
9, TABLE II
ST DWT CT
Polymer ( g/g )( ml /g )( g/g )
Comonomers employed in the Examples and identified in Table I by capital letters A to C, are identified below:
A - 2-~ydroxyethyl methacrylate B - Dimethylaminoethyl acrylate C - Mixture of 17.0 g. DMAEA + 1.9 g.
trimethylolpropane triacrylate ~5~ 'r'i ;1 ,:..
5~
, .
~o 9a~J O O cr~ ~\J N
'O ~ C) . . . I
tY~ I LO OJ ~) 0 ~1 ~1 ~7 1 ~ Ll~ 0 ~1 ;~
C
~ O
O ~
~>
~o O
~D ~O O O ~ ~ I a~
I j ~ Ln 0 ~ (D
H H ~ o ~ o o o a~
Q
o o o ~ ~o I "
. ~ r~ i ~ ~ ~ o o :~
u~ 0 ~ ~: X
~ ~ o a>
E
O
u~ ~
~ to a> ~1 X O ^ --~ o Lr O ~1 ~ ~ 5~ ~ ~ ~D
X s~ -- O ~ ~:
~ :~ N r~ o L~ ~ * u~
z ~ ~ ~ S~ O a E3 J ~s:: o v~ ¢ a ,I E ~ 1 0 0 E ~,1 0Q~ , o o c~ v cc H
X ~ E~ Zt~ ~ O ~;~
X~1~ r~ ~ H ~ _ _ *
~2~$.~
Copol~mers having substantially the same properties are obtained when in some of the above compositions potassium hydroxide was employed in place of sodium or ammonium hydroxide, 2,2~diethyoxyaceto-5 phenone in place of IRGACURE~651 and an oligomericsurfactant POLYWET~KX-3 (from Uniroyal) or TRITON N-lll (monophenoxy polyethoxy ethanol) in place of AEROSOL
Al02.
A number of testsare available to determine 10 the absorbency of a material. Following are descrip-tions of the two test procedures which were employed in evaluating absorbency of the interpolymers of this invention.
Static Test (ST) - A weighed film sample is immersed in 15 a test liquid for 10 minutes. It is then removed from the liquid, the excess liquid drained for a few seconds and then shaken lightly several times. The swelled sample is weighed again to determine the weight of liquid absorbed by the polymer.
20 Demand Wettability Test (DWT) - A test diaper is con-structed rom a-4 inch diameter pad (10.16 cm.) using materials from a commercial diaper. A film prepared from a polymer to be tested for absorbency is placed in the center of the test diaper between two layers of 25 fluff (wood pulp?. A diaper without the polymer film is used as a blank. The demand-wettability apparatus is a burette filled with the test fluid and rirmly stoppered at the top, with an air bleed on the side r and a delivery orificeon the bottom connected by a flexible 30 tube to the sample holder. The sample holder has an opening in the center which is connected to the flexible tube that leads to the delivery orifice of the burette.
The sample holder is level with the air ble~d opening in the burette. With this closed-system arrangement 35 the fluid in the flexible tube that comes up to the * trade mark ` ~z~s~
- 17 ,-opening in the sample holder is at zero pressure. Thus when the test diaper is placed on the sample holder over the opening it will absorb the fluid on its own through wicking action. The sample's own absorbent powder will 5 determine the rate and amount of fluid that will be withdrawn from the ~urette. The amount of fluid with-drawn at any given time can be easily read from the burette calibration. An additional feature is that absorbency can be measured against a range of pressures that can be obtained by placing various weights on top of the test diaper. Such pressures are intended to simulate the pressures applied on a diaper in actual use.
This test is described in greater detail by Lichstein, "Demand Wettability, a New Method for 15 Measuring Absorbency Characteristics of Fabrics", Symposium Papers-INDA Technical Symposium, 1974, pp.
129-142.
Compression Test (CT) - This test is a follow up test to the Demand-Wettability Test (DWT). After the sample has 20 absorbed the liquid against a lower pressure in a DWTest, it is removed from the DWT apparatus and placed atop a porous filter funnel. The sample is then subjected to 1.5 psi (0.105 kg/cm ) of pressure for 1 minute and the amount of liquid that is squeezed from the sample is 25 measured. Said pressure corresponds to the maximum pressure that is exertea on portions of a diaper when a toddler is picked up or held. This is 10 to 15 times the pressure that the diaper normally would experience.
The sample is then weighed to determine the amount of fluid in grams retained per one gram of polymer.
In Table II below is presented data comparing the absorbency properties of the copolymer of this invention with two other polymers. The polymer number in the Table corresponds to the example describing the 35 preparation of that specific polymer.
9, TABLE II
ST DWT CT
Polymer ( g/g )( ml /g )( g/g )
3 __ 37 31 . j~
Claims (9)
1. A water insoluble, flexible, highly water absorbent polymeric film having up to 25 mil thickness andcon taining water, said film being prepared by photopolymerizing a monomer mixture consisting of:
(a) 65 to 95 weight percent of acrylic acid, 60 to 100 percent of the carboxylic groups having been neutralized with an alkali metal hydroxide or ammonia base prior to polymerization, (b) 5 to 35 weight percent of a comonomer selected from the group consisting of 2-hydroxyethyl methacrylate and dialkylaminoalkyl acrylate or methacrylate wherein each alkyl of the dialkyl groups has 1 to 8 carbons and the other alkyl group has 2 to 6 carbons, (c) 0.01 to 5 weight percent, based on the total weight of the monomers, of a photoinitiator, (d) 0 to 5 weight percent, based on the weight of the monomers, of a cross-linking agent which contains two or more ethylenic unsaturations, and (e) a sufficient amount of water to render the resulting film flexible.
(a) 65 to 95 weight percent of acrylic acid, 60 to 100 percent of the carboxylic groups having been neutralized with an alkali metal hydroxide or ammonia base prior to polymerization, (b) 5 to 35 weight percent of a comonomer selected from the group consisting of 2-hydroxyethyl methacrylate and dialkylaminoalkyl acrylate or methacrylate wherein each alkyl of the dialkyl groups has 1 to 8 carbons and the other alkyl group has 2 to 6 carbons, (c) 0.01 to 5 weight percent, based on the total weight of the monomers, of a photoinitiator, (d) 0 to 5 weight percent, based on the weight of the monomers, of a cross-linking agent which contains two or more ethylenic unsaturations, and (e) a sufficient amount of water to render the resulting film flexible.
2. A film of claim 1, wherein about 80 to 100 percent of said carboxylic groups are neutralized.
3. A film of claim 1 or 2, wherein the comonomer is 2-hydroxymethylacrylate.
4. A film of claim 1 or 2, wherein said comonomer is said dialkylaminoalkylacrylate.
5. A film of claim 1 or 2, wherein said comonomer is said dialkylaminoalkylmethacrylate.
6. A film of claim 1 or 2, wherein said comonomer is dimethylaminoethylacrylate.
7. A film of claim 1 or 2, wherein the photoinitiator is used in an amount of from 0.1 to 5.0 weight percent.
8. A film of claim 1 or 2, containing 0.1 to 5 weight percent of said cross-linking agent selected from the group consisting of 1,3-butyleneglycol dimethacrylate, polyethyleneglycol diacrylate, polyethyleneglycol dimethacrylate, ethyleneglycol dimethacrylate, diethyleneglycol divinylether, tetraethyleneglycol diacrylate, trimethylolpropane trimethacrylate, triallyl isocyanurate, diallyl itaconate, allyl methacrylate, allyl pentaerythritol, and methylenebis(acrylamide).
9. A film of claim 1 or 2, wherein said photoinitiator is selected from the group consisting of 2,2-dimethoxy-2-phenylacetophenone, benzophenones, benzoin ethers and mixtures thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US16693680A | 1980-07-08 | 1980-07-08 | |
| US166,936 | 1980-07-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1209524A true CA1209524A (en) | 1986-08-12 |
Family
ID=22605280
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000379531A Expired CA1209524A (en) | 1980-07-08 | 1981-06-11 | Hydrophilic interpolymers of acrylic acid and acrylate |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0055728A4 (en) |
| JP (1) | JPS57500930A (en) |
| KR (1) | KR830006364A (en) |
| BE (1) | BE889553A (en) |
| BR (1) | BR8108674A (en) |
| CA (1) | CA1209524A (en) |
| DK (1) | DK160259C (en) |
| ES (1) | ES8300804A1 (en) |
| GR (1) | GR75718B (en) |
| IT (1) | IT1137264B (en) |
| MX (1) | MX160466A (en) |
| WO (1) | WO1982000147A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4654039A (en) * | 1985-06-18 | 1987-03-31 | The Proctor & Gamble Company | Hydrogel-forming polymer compositions for use in absorbent structures |
| USRE32649E (en) * | 1985-06-18 | 1988-04-19 | The Procter & Gamble Company | Hydrogel-forming polymer compositions for use in absorbent structures |
| JP2817923B2 (en) * | 1987-10-30 | 1998-10-30 | デヴァーズ・エムエス・カンパニー | Solid state battery |
| CA2136674A1 (en) * | 1994-06-30 | 1995-12-31 | William G. Reeves | Hydrogel-forming polymeric material with desirable fracture properties |
| EP1035142A1 (en) | 1999-03-09 | 2000-09-13 | Nidek Co., Ltd. | Acrylic copolymer materials suitable for ophthalmic devices |
| FR2876374B1 (en) * | 2004-10-11 | 2007-02-23 | Arkema Sa | USE OF PHOSPHORIC ESTERS AS ANTI-DEPOSITION AGENTS DURING THE SYNTHESIS, PURIFICATION OR REGENERATION OF (METH) ACRYLIC MONOMERS |
| US7838610B2 (en) | 2005-09-30 | 2010-11-23 | Nippon Shokubai Co., Ltd. | Ion-sensitive super-absorbent polymer |
| JP4994175B2 (en) * | 2007-09-28 | 2012-08-08 | 富士フイルム株式会社 | Planographic printing plate precursor and method for producing copolymer used therefor |
| CN112094372B (en) * | 2019-06-17 | 2023-07-14 | 荒川化学工业株式会社 | Binder aqueous solution for lithium ion battery, slurry for negative electrode, material for negative electrode, and lithium ion battery and method for producing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2511880A (en) * | 1950-06-20 | Resins of alkyl-substituted cyclo | ||
| US2473544A (en) * | 1946-03-29 | 1949-06-21 | Chessie E Rehberg | Polyalkyl-cyclohexanol acrylates |
| US2882261A (en) * | 1954-07-21 | 1959-04-14 | Du Pont | Thermoplastic molding composition of cyclohexyl methacrylate, methyl methacrylate and an acrylic acid ester of a saturated alcohol having less than 3 carbon atoms |
| US2945013A (en) * | 1956-03-22 | 1960-07-12 | Monsanto Chemicals | Water-soluble interpolymers of acrylic acids and 2-ethylhexyl esters of acrylic acids and method of making same |
| US3090736A (en) * | 1960-01-27 | 1963-05-21 | Dow Chemical Co | Insoluble polyacrylic acid salts and method of preparing the same |
| DE1495381B2 (en) * | 1963-09-07 | 1971-06-24 | Czeskoslovenska akademie ved , Prag | METHOD FOR MANUFACTURING CONTACT LENSES OR CONTACT LENS BLOCKS FROM SWELLABLE HYDROGELS |
| US3468980A (en) * | 1966-01-17 | 1969-09-23 | Rohm & Haas | Flame resistant acrylic sheet containing cyclohexyl acrylate or methacrylate copolymer |
| US3634366A (en) * | 1968-05-23 | 1972-01-11 | Daicel Ltd | Polymerizing method |
| DE1965740C3 (en) * | 1969-12-31 | 1979-11-22 | Bayer Ag, 5090 Leverkusen | Process for the production of powderable acrylic resins |
| US3764502A (en) * | 1971-08-12 | 1973-10-09 | Ici America Inc | Water soluble sodium acrylate polymers of high molecular weight |
| GB1439132A (en) * | 1972-03-13 | 1976-06-09 | Special Polymers Ltd | Method for the production of a hydrophilic polymer product |
| DE2236513C3 (en) * | 1972-07-26 | 1978-12-07 | Deutsche Gold- Und Silber-Scheideanstalt Vormals Roessler, 6000 Frankfurt | Stoving powder varnish |
| US4115331A (en) * | 1973-05-31 | 1978-09-19 | Sanyo Chemical Industries, Ltd. | Surface sizing compositions for paper |
| US3915921A (en) * | 1974-07-02 | 1975-10-28 | Goodrich Co B F | Unsaturated carboxylic acid-long chain alkyl ester copolymers and tri-polymers water thickening agents and emulsifiers |
| US4172177A (en) * | 1975-06-17 | 1979-10-23 | Kyowa Gas Chemical Industry Co., Ltd. | Water insoluble hydrophilic polymer composition |
| US4062817A (en) * | 1977-04-04 | 1977-12-13 | The B.F. Goodrich Company | Water absorbent polymers comprising unsaturated carboxylic acid, acrylic ester containing alkyl group 10-30 carbon atoms, and another acrylic ester containing alkyl group 2-8 carbon atoms |
| US4066583A (en) * | 1977-05-16 | 1978-01-03 | The B. F. Goodrich Company | Flexible water absorbent polymer compositions comprising (a) unsaturated carboxylic acid, acrylic ester containing alkyl group 10-30 carbon atoms, additional monomer plus (b) aliphatic diol |
| US4167464A (en) * | 1978-10-16 | 1979-09-11 | The B. F. Goodrich Company | Photopolymerized hydrophilic interpolymers of unsaturated carboxylic acid and esters |
-
1981
- 1981-06-08 BR BR8108674A patent/BR8108674A/en not_active IP Right Cessation
- 1981-06-08 EP EP19810901866 patent/EP0055728A4/en not_active Withdrawn
- 1981-06-08 JP JP56502263A patent/JPS57500930A/ja active Pending
- 1981-06-08 WO PCT/US1981/000764 patent/WO1982000147A1/en not_active Application Discontinuation
- 1981-06-11 CA CA000379531A patent/CA1209524A/en not_active Expired
- 1981-06-25 GR GR65338A patent/GR75718B/el unknown
- 1981-06-29 IT IT22628/81A patent/IT1137264B/en active
- 1981-07-03 ES ES503685A patent/ES8300804A1/en not_active Expired
- 1981-07-03 KR KR1019810002426A patent/KR830006364A/en unknown
- 1981-07-08 MX MX188207A patent/MX160466A/en unknown
- 1981-07-08 BE BE0/205351A patent/BE889553A/en not_active IP Right Cessation
-
1982
- 1982-03-05 DK DK098082A patent/DK160259C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| BE889553A (en) | 1981-11-03 |
| KR830006364A (en) | 1983-09-24 |
| GR75718B (en) | 1984-08-02 |
| EP0055728A1 (en) | 1982-07-14 |
| DK160259B (en) | 1991-02-18 |
| IT8122628A0 (en) | 1981-06-29 |
| ES503685A0 (en) | 1982-11-01 |
| EP0055728A4 (en) | 1982-08-11 |
| BR8108674A (en) | 1982-05-25 |
| MX160466A (en) | 1990-03-08 |
| JPS57500930A (en) | 1982-05-27 |
| IT1137264B (en) | 1986-09-03 |
| ES8300804A1 (en) | 1982-11-01 |
| WO1982000147A1 (en) | 1982-01-21 |
| DK160259C (en) | 1991-07-22 |
| DK98082A (en) | 1982-03-05 |
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