|Title of Invention||
"A SWELLING PASTE"
|Abstract||A swelling paste consisting of an aqueous mixture of a water-soluble polymer containing carboxyl groups as herein described, constituted by more than 75 mole-% of monomers containing carboxyl groups as herein described, the carboxyl groups thereof being present as a salt to an extent of from 40 to 65 mole-%., 0.5 to 30 wt-%, based on the weight of the polymer employed, of at least one alkoxylated, multifunctional alcohol as herein described, and optionally 0 to 30 wt-% of further additives as herein described.|
|Full Text||The present invention relates to a swelling paste.
The present invention relates to a printable swelling paste containing a mixture of polymers having carboxyl group and a crosslinker containing polyhydroxyl groups. The swelling paste is suitable for coating support materials such as fibers, fleeces, fabrics, and films and is crosslinked thereon under termperature influence to yield a polymer which absorbs aqueous liquids. The swelling past is remarkable for its high storage stability and exhibits extraordinarily high and rapid swelling properties in the crosslinked stated.
Superabosrobent polymers are known for a long time and commercially available in the form of powders, e.g., under the designation of FAVOR or CABLOC. However, the processing of powders is technically expensive and, once abraded particles give rise to breathable fines, not harmless in terms of occupational medicine.
It is already well-known to perform the polymerizations of monomer solutions on prefabricated surfaces or filaments. However, these processes are a domain of chemical industry factories because of the protective gas technique required and the safety regulations to be observed and cannot be transferred to factories of other industrial sectors such as the printing and textile industries.
The teaching of EP 482,703 wherein a water-in-oil emulsion of a superabsorbent material is applied onto aramide fibers and the liquid components are subsequently evaporated by heat, neither offers an optimum solution because in this case, the complete oil phase is transferred into the exhaust
air and therefore, expensive exhaust air purification proce-dures must be performed.
EP 188,091 describes absorptive porous sheet materi-als produced by padding a mixture df an aqueous solution of a non-crosilinked prapolymer with a crosslinker onto a fleece and subsequent thermal cross linking, This process is disad-vantageous in that the polyhaloalkanol, haloepoxyalKane and polyglycidyl ether type crosslinkers may be added just a short time before processing due to their reactivity, because otherwise undesirable thickening of the mixture takes place already during storage, and the above-described crosslinkers are highly critical for health reasons.
EP 357/474 describes spraying of low-viscosity aqua-ous solutions of non-crosslinked polyacrylic acids on sheet fabrics made of cellulose and subsequent thermal crosslinking by simultaneously applied cro$slinkers to give water-swell-able gels. Multivalcnt metal ions, as well as epoxides, azir-idinea, polyglycidyl ethers are described as croselinkers which, due to their cancerogenic potential, are barely usable anymore, the hygienics and food packaging industrial sectors being considered as particularly problematic, in addition, when storing the coating solutions, they give rise to early crosslinking already at room temperature, so that further processing of the highly viscous I end/or gelled mass is no longer possible.
The EP 361,842 describes the production of absorbent sheet materials using fibers of copolymers containing carbox-
yl groups, which are crosslinked with heterocyclic carbonates or compounds having at leaet two jfree hydroxyl groups. The copolymern consist of from 25 to 75 mole-% of monomers having carboxyl groups and from 75 to 25 mole-% of other monomers, the carboxyl groups being neutralized to a degree of from 20 to 80%. Maleic acid(anhydride) type dicarboxyl.ic acids(an-hydrides) are mentioned as typical unsaturated carboxylate
, which are copolyaierized with hydrophobic comonomers such as iaobutylene, ethylene and styrene. The embodiments ate confined to a maleic anhydride/isotoutylene copolynier. However, the water-absorbing fibers thus produced are disad-vantageous in that they are highly brittle and fragile at low humidity, tend to ba tacky and deliquescent at high humidity, and have low swalling values. For this reason, theee delicate structures are not processed alone but only in combination with a supjjorting fabric. However, for many applications such aa in the cable industry or as back sheet in the hygienics industry, such fabric/filament combinations are excessively thick and thus, unsuitable.
DE 195 21 431 Al describes a process wherein reactive crosslinkers such as polyfunctional epoxides, aziridines, pglyglycidyl ethers, and epihalohydrines are added to an aqueous solution of a pre-crosslinked polyacrylic acid just prior to the printing process. Although, an already printable paste is described therein, these reactive crosslinkers have the crucial disadvantage that most of them are highly criti-cal in toxicological terms and therefore, are processed only reluctantly in the printing industry or under stringent pro-visions affecting process economy. Another drawback of this system is that the mixture of the two components cannot be stored for long but must be prepared freshly again and again due to theckening which already begins at room temperature, The application cited above illustrates and exemplifies that, less reactive components such as substances having free alco-hol or amino functions are unsuitable as crosslinkers for polyacrylic acids.
US 4,017,653 describes a process for the production of an absorbing article coated with a water-swellable poly-electrolyne, coating being effected using a solution of the polymer and crosslinks in alcohol and/or water, Crosslinkers used therein are those from the group of haloalkanols, halo-epoxide compounds, polyglycidyl compounds and sulfonium zwit-
terione. Considering ecological and health-related aspects, the eroisl.inkers must be rated critical, their crosslinking activity boing high to a extent that even at low cross linker concentrations , gelling of the coating solution takes place within 2 days, rendering further process ing imponeible.
WO 96/23024 claims substrates coated with a mixture of polymer and crossliuker, which are crosslinked by heat and exhibit au.perabforbent properties. There is only one, yet incomplete theoretical example, wherein a combination of A pre-cross linked poly (meth) acrylic acid and an unspecified bivalent erosslinker is mentioned. Neither are there detailed statements concerning the properties of the poly mer/crosslinker mixtures and the chemistry of the crosslink-er, nor the conditions of crosslinking,
Therefore, the invention is based on the object of providing an aqueous, process able paste which already in-cludes a crosslinker and nevertheless, may be stored for a prolonged period of time, with no increase in viscosity tak-ing place during storage that would impede processing. The term printable is understood to indicate that further addi-tives in the paste prior to coating on a prefabricated sheet material are not absolutely necessary in order to provide the desired properties after a thermal subsequent treatment, i.e., to dwell in the presence of water or aqueous solutions, thereby increasing the original volume by a multiple. Thus, swelling as demanded by the cable industry should be at least 8 mm, preferably 10 mm, and particularly preferred, at least 12 mm with a dry substance coating of 100 g per m2, and should reach a relative swelling height after 30 a of at least 4 mn/100 g in order to provide rapid blocking of enter-ing water, i.e., to achieve an excellent water- sealing ef-fect. To ensure sufficient gel stability, the retention should have values of at least 15 g per g of polymer, prefer-ably at least 25 g/g, and more preferably at least 40 g/g since otherwise, it must be assumed that the swelling height
determined in a short-term test will decrease again on pro-longed connot with, water.
Further, the paste must be free of highly inflammable or hazardons substances and should have a viscosity behavior at room temperature, which ie desirable lor a printing medi-um. At the same time, stringing should be as low as possible. In particular, the crosslinkers should not contain substances which are hazardous to health, such as epoxidos, halohydrines and other halogen compounds. Crosslinking should be possible at temperatures of from 150'C to 250.C, wherein crosslinking periods oil a few minutes are demanded due to the thermal loadability of the base material and for economical reasons. It is particularly preferred that crosslinking be complete after fivo minutes at a temperature of 180'C or after one minute at 200'C. Thereafter, the imprinted sheet material must be capable of being rolled without sticking and should virtually be free of substances capable of migrating.
Surprisingly, the object of the invention was accom-plished using a combination of a water-soluble polymer con-taining carboxyl groups (preferably, partially neutralized polyacrylic acid), which polymer is constituted by more than 75 mole-% of monomers containing carboxyl groups, and at least one multifunctional alkoxylated alcohol in aqueous solution, where the aqueous mixture of carboxyl group-con-taining polymer and multifunctional alcohol may optionally contain further additives.
Hsreinbelow, multifunctional alcohols are understood to be alkoxylation products as well, particularly the eth-oxylation products of amines and aminoalcohole, which contain at least 2 OH groups.
More specifically, the ethoxylates of ethylene glycol having a molecular weight of from 200 to 1,000, as well as glycerol, trimethylolpropane, butanediol, pentaerythritol,
and sorbitol may be mentioned, for example. Furthermore, ethoxyletes of ethylenediamine, diethylenstriaraine or etha-nolamine, diethanolamine or triethanolamine are possible. Also, condensation products of ethanolamines with polycarbox-ylic acids such ae euccinic acid or adipic acid may be used as crossliokters. Surprisingly, the ethoxylated crosslinkers are more effective compared to the non-ethoxylated base mole-cules and are preferred for this reason. Preferably, the number of OH moieties in the ethoxylate chains should not exceed a value of 10.
Thus, the invention is directed to a swelling paste made of an aqueous mixture of a water soluble polymer con-taining curboxyl groups and at least one multifunctional alcohol and optionally further additives, which is character-ized in that the polymers are constituted by more than 75 mole-% of monomers containing carboxyl groups, the carbox-yl groups thereof being neutralized to an extent of from 40 to 65 mole-%, and the multifunctional alkoxylated alcohol serving as crosslinker is present at a concentration of from 0.5 to 30 wt.-%, based on the weight of water-soluble, car-boxyl group-containing polymer employed.
Surprisingly, it was found that in order tO accom-plish the object of the invention, the carboxyl groups of the carboxyl group-containing polymer used, preferably polyacryl-ic acid, must be present as salt to an extent of from 40 to 65 mole-%, preferably from 45 to 60 mole-%, The salts are formed using univalent cations such as potassium, sodium, ammonium .and alkylammonlum. If the neutralization degree is above the limits according to the invention, only slight crosslinking results under the conditions indicated, With a product thus produced, an excessively soft gel is formed which is actually capable of absorbing water but does not permit a swelling height to be determined. If the neutraliza-tion degree is less than 40 mole-%, crosslinking does actual-ly occur, but swelling of the obtained crosslinked polymeri-
zate upon contact with aqueous solutions takes place to only e minor extent and above all, very slowly.
Particularly.suitable a* multifunctional elkoxylated alcohols with crosslinking effect are those based on the members of the group selected from ethylene glycol, 1,3-pro-pylene glycol, glyeerol, 1,4-butenediol, trimethylolpropene, erythritol pentaerythritol, and hydrogenated sugars. The multifunctional alcohols may be employed alone or as mixtures of each other, Alkoxylation is effected using ethylene oxide. More specifically, the ethoxylates of ethylene glycol, as well as those of glyeerol, trimethylolpropane, l,4-butan-diol, pentaerythritol and/or sorbitol are to be mentioned, for example, these ethoxylates preferably having a molecular weight of from 200 to 1,000, and at least 1 mol ethylene oxide per :nol of alcohol, preferably at least 1 mol ethylene oxide per mol of OK group being reacted.
The mixtures of polymer and crosslinker according to the invention may be stored for a long period of time, with properties not being lost. In particular, they have excellent viscosity stability, permitting prefabricatlon of ready-to-use swelling pastes and relieving the end user from the ne-cessity of mixing the pastes with crosslinkers.
For economical and technical reasons, the polymer content of the aqueous solutions is at least 10, but prefera-bly more than 30 wt.-%; however, higher concentrations may be realized as well, depending on the particular use.
The ratio of crosslinkers employed depends on the molecular weight and functionality and normally ranges be-tween 0.5 and 30 wt.-%, preferably between 1 and 20 wt,-% and particularly preferred, between 1 and 15 wt,-%, based on the polymer ratio in the swelling paste, Due to its excellent stability, the mixture may be stored as such or marketed, or may be prepared as late as by the processing user, the
linker concentration being adjusted to the desired product properties, such as a swe11ing rate, swelling height and gel stability. As a result of its storage stability, it is possi-ble that the prepared paste is stored by the processing user for a prolonged period of time, and to run several operations with same.
As carboxyl group-containing monomers, methacrylic acid, maleic anhydride, fumaric acid, itaconic acid and the •alts and mixtures of these monomers are possible in addition to acrylic acid. However, acrylic acid and/or sodium aerylate-are preferably used.
Uee of other comonomors, as well as slight pre-cross-linking is possible, the monomers containing carboxyl groups invariably being present at a level of more than 75 mole-%. In case a pre-crosslinker is to be used in polymer produc-tion, it must be ensured that the polymer may still be pro-cessed in the form of an aqueous solution and is not present merely in the form of swelled gel portions due to excessively high crosslinking, which cannot be processed in a swelling paste anymore. Therefore, the primary crosslinker is normally used with 0.1 mole-% at maximum.
For example, though not exclusively, (meth)acryl-amide, vir.yl acetate, vinylsulfonic acid and the salts there-of, 2-acrylamido-2-methylpropanesulfonic acid end the salts thereof, (meth)allyl alcohol and the alkoxylation products thereof, .is well as mono(meth)acrylic esters of multivaient alcohols or of univalent alcohol alkoxylates are to be men-tioned as monomers not containing carboxyl groups, which are incorporated in the polymer at a level of 20 mole-% at maxi-mum. The comonomers are used to modify the polymer proper-ties, e.g., to improve adherence to the support material. Co-use of vinyl or (meth)aerylate esters as comonomers is advan-tageous in flexibilizing films which may be produced from the swelling pastes of the invention. For example, using monomers
containing aulfonate or aulfonic acid, an improved salt sta-bility may be achieved when using the crosslinked swelling paste. Among these monomers, the group consisting of acryl-amide, methacry1amide, hydroxyathyl acrylate, aLlylsuifonic acid, methallylsulfonic acid, acrylamidopropanesulfonic acid and mixtures of these monomors is preferred.
the aqueous pplyaerylic acid may contain further additives having advantageous effects, which arc not polymer-ized therein. In particular, substances far reducing the brittleneiis (hardness) of the dried product, those for tack reduction, for improving the printing viscosity, and for increasing the conductivity are possible. Thus, in order to improve the gel stability and to adjust the desired printing viscosity, common thickeners effective in water, such as cellulose derivatives or more highly erosalinksd polyacry-lates, e.g., those sold by the stockhausen company under the designation of "Cabloc CTF" may be added. They do not swell in the polyacrylate solution as usual, yet improve signifi-cantly the viscosity behavior during the printing process, The additives are present with usual amounts, advantageously not more than 30 wt.-%, particularly not more than 20, and more preferably not more than 10 wt.-%, based on swelling paste.
The swelling paste of the invention is preferred to have a viscosity of at least 800 mpa-s, preferably at least 2,000 mPa.s and 25,000 mPa.s at maximum, preferably 20,000 mPa.s at maximum, determined using a 30 wt.-% aqueous solution of polymer employed.
The swelling paste thus produced may be applied on a prefabricated sheet material or on filaments according to well-known methods. Here, imprinting or knife coating on fabrics or nonwovene using a template is preferably chosen in order to achieve a uniform pattern with regular spacings between the single paste spots. Furthermore, it; is possible
Co «oak a nonwoven with this paste in a padder and sub-sequently squeeze it off to the desired liquid content. The swelling paste nay be applied onto yarns as described ia EP 482,703, for example.
Instead of a fabric, a film may also be printed with the swelling paste on one side, in which case it is advanta-geous for adherence of the paste spots when- the aide of the film to be printed has been roughened uiing suitable means, or laminated with a thin fleece. Films printed in this fash-ion may be used with particular advantage in those cases
where it it important that the water barrier layer is not rendered excessively thick, ae is the case with communication. cables, for example. There ere a number of organic film mate-rials which resist the temperature load during the printing and crosslinking operations, such as, though not exclusively, polyimide, polyaulfonic, polycarbonate, polyethylene tere-phthalate and polytetrafiuoroethylene films* Likewise, metal-lic or metallized films are used.
Subsequently, the polymer thus coated must be sub-jected to crosalinking, which may be achieved by a short-term thermal treatment, the duration of the thermal treatment depending on the temperature and the neutralization degree of the polymer-bound carboxyl functions and the temperature stability of the support material, In any event, the cross-linking temperature must be below the shrinking temperature of the support being in the form of, e,g., fabric/nonwoven filaments or a film. With sheet materials, it is commonly between 150'C and 250.C, preferably between 180 and 200oC. For economical reasons, the available time for crosslinking is generally less than 5 minutes, preferably less than 2 minutes. Here, it is possible to perform drying and cross-linking at a constant temperature or to select a temperature program to allow steps such as drying and crosslinking to be run at various temperatures. Also, a short-term subsequent heating, e.g., using an IR radiator, may be advantageous.
After drying and crosslinking post-cure, the swelling paste of the invention advantageously has a swelling height per 100 q of at least 8 mm, preferably at least 10 mm, and more preferably at least 12 mm, and A relative swelling height after 3D 9 of at least 4 mm/100 g, and in addition, has a retention of at least 15 g/g dry weight, preferably at least 25 g/g, and more preferably at least 40 g/g dry weight.
Also, fibers having high thermal stability, such as ararcide fibers or glass fibers may be impregnated with the swelling paste of the invention and subsequently subjected to a thermal treatment. Because these fibers have significantly higher thermal stability compared to fabrics or fleeces, but residence times of only a few seconds are economically feasi-ble, temperatures of up to 400.C are applied in this case.
Mostly, the production of support-free films is ef-fected on a reusable intermediate support, from which, the film is rmoved after crosslinking and optional conditioning. AS to the molecular polymer structure, care must be taken that film flexibility sufficient for further use is achieved by using comonomers, if necessary.
The finished substrate may find use in various indus-trial fields, such as the cable industry, the hygienics in-dustry, in food packaging, in landscaping applications, in the clothing industry, or even in the burial business.
In order to test the swelling paste for two-dimen-sional fabrics, it was knife-coated on a polyester fabric on a comber table using a template and subsequently dried in a circulating air oven, A uniform pattern of spots was con-stantly obtained.
Application-technical measurements :
Measurement of swalling height and swelling rate
To measure the swelling height and the swelling rate, a circular piece (25.4 cm2) of tha coated sheet material is placed in a plastic beaker having an inner diameter of 80,5 mm and • height of 30 am. First, a thin polyester fleece (0.5 mm in thickness) and then a round piston having a diame-ter of 80 mm and a weight of 100 g are placed on top of the above fleece. The piston has (0 through borings of 2 mm diam-eter each. During measurement, the level of the piston upper edge if observed, using an instrument by the Mitutoyo company (IDU 25). 75 ml of VE water ( Tha procedure for determining the relative swelling height is the same as for determining the swelling height, with the exception that the zero value from the swelling height measurement is subtracted from the finel value.
Fiber tightness teat
The test has been described in EP 482, 703 page 4, lines 5 off.
Determination of retention
In order to determine the retention, a circular piece of the imprinted fabric having a diameter of 3 cm i$ welded in a commesrcially available tea bag. The bag is then immersed in a dish with distilled water for thirty minutes, suspended
for 10 minutes and centrifuged at 1,200 rpm in a commercially available spin dryer for 5 minutes. The weight of the centri-fuged tea bag is determined. TO estimate the retention, the weight of i;he dry tea bag including the fabric is subtracted from the woight of the centrifuged tea bag and divided by the weight of printed polymer.
The composition of the polymers and crosalinkers,as well as swelling heights and relative swelling heights of the pastes according to the Examples and Comparative Examples can be inferred from Table 1.
A polyacrylic acid having a neutralization degres of 50% (counter-van: sodium), a product viscosity (TS 32% in water) of 12,300 mPa.s, measured at room temperature using a Brookfielc, viscoaimeter, and a molecular weight Mp of 120,000 g/ftiol and an Mw of 155,000 g/mol (determined by means of GPC against polyacrylic acid standard), and a ratio of polymers having a molecular weight of below 10,000 g/mol of less than 5 wt,-% was used for the printing test. This poly-acrylic acid was mixed with 3 wt.-% of imbetin SOR/060 (a 6EO sorbitol manufactured by Kolb AG) and 3.5 wt.-% of Cabloc CTF and subsequently printed on a polyester fabric uesing a perfo-rated template. The imprinted fabric was heated at 190'C for 2 minutes in a drying oven. The product had a coating of 16.5 g/m2 2 and a swelling height of 2.38 mm after 30 sec-onds, 2.6 mm after 1 minute, and 2.8 mm after 10 minutes. The relative swelling height after 30 6 was 12 mm/100 g. Accord-ingly, the 10 minute value per 100 g dry coating wos 17 mm/100 g. The retention was 49.5 g/g of dry coating.
The procedure was as in Example 1, but instead of pure polyacrylic acid, a copolymer of 95 mole-% acrylic acid and 5 mole-% acrylamide was used. 50 mole-% of the acrylic acid functions in this polymer were present as sodium salt. At a dry substance of 31.5% at room temperature, this polymer had a viscosity of 10,700 mPa-s (determined using a Brook-field rotary viacosimeter) . According to GPC (comparison with polyacrylic acid standard), this polymer had an Mp of 160,000 g/mol and an Mw of 200,000 g/mol. The ratio of homo-logues having a molecular weight below 10,000 g/mol was less than 31, The product obtained after drying had a dry coating of 18 g/m2 end a swelling height of 1,71 nun after 1 minute, and 1,82 mm after 10 minutes. The relative swelling height after 30 s was 4,5 mm/100 g. Thus, the 10 minute value per 100 g of coating was 10 mm/100 g. The retention was 31.4 g/g,
The procedure was as in Example 1, but instead of pure polyacrylic acid, a terpolymer of 94 mole-% acrylic acid, 5 mole-% acrylamide and 1 mole-% methoxypolyethylene glycol( 1,000) methacrylate (Bieomer s 10W) was used. 50% of the acrylic acid in the polymer were present as sodium salt. The polymer had a viscosity of 2,180 mPa-s (determined using a Brookfield rotary viscosimeter at a TS of 30%). At a dry coating of 17 g/m2, a swelling height of 1.94 mm was deter-mined after 1 minute, and of 2,36 mm after 10 minutes. The relative swelling height after 30 s was 5.82 mm/100 g. Thus, the 10 minute value per 100 g of coating was 13.9 mm/100 g. The retention was determined to be 68.5 g/g.
The procedure was as in Example 1, except that the fabric was heated at 185 'C for only 2 minutes in a Matthis
dryer And subsequently for 8 seconds under a IR lamp. The product hail a dry coating of 19 g/m2 and a swelling height of 2.2 mm after 30 seconds, 2,3 mm after 1 minute, and 2.5 mm after 10 minutes. Thus, the 10 minute value per 100 g of dry coating was 13 mm/100 g. The retention was 54 g/g of dry coating.
The.e procedure was as in Example 1, except that Cabloc CTF was omitted, The final mixture of polyacrylic acid and 3 wt.-% of. Imbetin SOR/060 had a viscosity of 10,300 mPa-5. The product had a dry coating of 17.1 g/m2 and a swelling height of 2.11 mm after 30 seconds, 2.18 mm after 1 minute, and 2.21 jnm after 10 minutes. The relative swelling height after 30 a was 9.82 mm/100 g, Thus, the 10 minute value per 100 g of dry coating was 13 mm/100 g. The retention was 28 g/g of dry coating.
The procedure was as in Example 1, but instead of Imbetin SOR/060, 3.3 wt.-% of an addition product of four moles ethylene oxide to trimethyloipropane was employed. The imprinted fabric was heated for 2 minutes at 200. c in a dry-ing oven, The product had a dry coating of 16.3 g/m2 and a swelling height of 1.26 mm after 30 seconds, 1.59 nun after one minute, and 1.85 mm after 10 minutes. The relative swell-ing height after 30 s was 5,64 mm/100 g. Thus, the 10 minute value per 100 g of dry coating was 11.3 mm/100 g. The reten-tion was 36 g/g of dry coating.
The polymer of Example 1 was diluted 1:1 with dis-tilled water, resulting in a solution having a Brookfield viscosity of 240 mPa-s. This solution was mixed with
1.5 wt.-% of Imbetin SOR/060 and subsequently applied onto aramide fibers. The aramide fibers thus treated were subject-ed to a short thermal treatment using a hot-air hairdryer. The treated aramide fibers were subjected to a swelling teat as described in SP 482,703, page 5, from line BO on, thereby obtaining fibers having a polymer coating of 15 wt.-%. These coated fibers were immediately tight in the welling test and maintained tightness until the end of testing after 6 days.
The polymer of Example 1 was mixed with s wt.-% of a 20EO trietthanolamine and coated without cabloc on a polyester fabric using a perforated template and a comber. The coated fabric wan dried at 200'C for 3 minutes and subsequently heated for 12 seconds using an IR lamp. The product had a dry coating of 22 g/m2 and a swelling height of 2.0 mm after 30 seconds, 2.4 mm after 1 minute, and 2.6 mm after 10 minutes. The relative swelling height after 30 s was 6.02 mm/100 g. Thus, the 10 minute swelling height value was 11,8 mm/100 g of dry coating. The retention was 44 g/g of dry coating.
The polymer of Example 1 was diluted 1:0.75 with distilled water and following addition of 3 wt.-% of Imbetin SOR/060, coated on a polyester fleece (weight per unit area: 100 g/m2) in a padder, using a flow rate of 2.4 m/min. Super-natant liquid was squeezed off between two rubber rollers, using a pressure of 2 bars. Thereafter, the wet fleece was dried at 185'C for five minutes, A fleece having a polymer coating of 23.9 g/m2 wag obtained, The solid absorption and centrifuge retention after an immersion period of 30 minutes were determined for this fleece (described in DE 41 38 408, page 7, lines 43ff for an immersion period of 10 minutes). Solid absorption; 26.9 g/g of polymer/ retention: 8.3 g/g of dry coating.
The procedure was as in Example 1, with the exception that a different polyacrylic was used. This was a polyacrylic acid which was present to 50% as sodium salt, had a viscosity of 900 mPa-s at a TS of 32 Wt.-% (measured at room tempera-ture uaincf a Brookfield rotary viscosimeter), and an Mp of 15,000 g/mol and an Mw of 39,300 g/mol (measured using GPC against polyacrylic acid standard), and wherein 30 wt.-% of the molecular weight proportions were below 10,000 g/mol. The swelling height after 10 minutes was 1.65 mm at a coating of 14 g/m2. This correspond! to a 10 minute swelling height per 100 g of coating of 11,8 mm. The retention was 11,2 g/g.
A polymerizate as described in Example 1, but having a neutralization degree of 45 mole-% and a viscosity of 14,800 mPa-s at 31% TS, was stirred with 3 wt,-% of Imbetin SOR/06, printed, and crosslinked for 2 minutes at 190.C. Retention: 14 g/g, swelling height after 10 minutes: 1.6 mm, dry coating 18 g/m2, swelling height per 100 g: 8.9 mm.
The procedure was as in Example 1, except that the polymerizate had a neutralization degree of 55 mole-%, a viscosity of 14,900 mPa-s, and a TS of 30%. Retention: 59 g/g, evening height after 10 minutes; 2.0 mm, dry coat-ing: 19.5 g/m2, swelling height per 100 g: 10.3 mm.
Starting from a 30 wt.-% aqueous solution of a poly-acrylic acid (21,200 mPa-s) which was 50 mole-% neutralized with sodiun hydroxide solution, a swelling paste wae produced using 3 wt.-% of Imbetin SOR/060, which exhibited the follow-
ing properties after coating on fabric and cross linking (2 minutes, 190.C): dry coating? 9.2 g/ma, retention; 50.3 g/g, swelling height after 10 minutes; 1.6 mm, swelling height per 100 g: 17,4 mm, relative swelling height after 30 s; 7.61 mm/ICO g.
Example 13 was repeated, with the proviso that the crosslinkir was added within 1 hour at 90'C. Dry coatings 19 g/m2, rstention: 21 g/g, swelling height after 10 minutes: 1.9 mm, swelling height per 100 g; 10 mm, relative swelling height after 30 s: 4.21 mmm/ 100 g,
The procedure was as in Example 5, but instead of the polyester fabric, a polyimide film (50 Mm in thickness) was used as substrate and imprinted. The imprinted film was heat-ed at 195'C for 2 minutes in a drying oven. The product had a dry coating of 16 g/m2 and a swelling height of 1,95 mm after 30 seeonds, 1.99 mm after 1 minute, and 2.12 mm after 10 minutes. The relative swelling height after 30 s was 10.94 mm/100 g. The 10 minute value per 100 g of dry coating was 13.2 πm/100 g, the retention was 48 g/g of dry coating.
The final mixture of Example 5 was stored for six months and re-measureds viscosity: 10,200 mPa-s. The product was printed as in Example 5, Dry coatings 16.6 g/'m3, swelling height after 30 seconds: 2.05 mm, after one minute: 2.11 mm, and after 10 minutes: 2.10 mm. The relative swelling height after 30 s was 9.70 mm/100 g, The 10 minute value per 100 g of dry coating was 12,7 mm/100 g, The retention was 30 g/g of polymer.
Comarative Examle 1
Isbam 10 (maleic aeid/isobutylene copolymer) was saponified using water and sodium hydroxide solution SB de-scribed in Example 3 of EP 361,842 A2. Subsequently, the saponified product was stirred with the indicated amount of butanedio]. and pentaerythritol at 90oC for one hour and then printed on a polyester fabric. Crosslinking was performed at 190oC for 2 minutes. The following properties ware obtained; dry coating: 30.3 g/m2, retention: 8.9 g/g, swelling height after 10 minutes: 1.3 mm, swelling height per 100 g: 4.2 mm.
Comparative -Examples 2-5
The procedure was as in Example 1, except that the polyacrylic acid had neutralization degrees of 3.5 wt.-%, 25 wt.-%, 75 wt.-%, and 100 wt,-%. The swelling height and retention of each product were determined and are indicated in the following Table and in Table 1, respectively.
Comparative Example 6
According to the teaching of EP 357,474, a polyacryl-ic acid, rs 30%, pH 5.0, viscosity 250 mPa-e, was stirred with 4 wt.-% of iron(II) sulfate, baeed on ws. when storing at room temperature, the product exhibited a viscosity of
1,400 mPa-s after only 6 hours, and more than 100,000 mPa-s after 24 hours. Having such a viscosity, the product can no longer be sprayed as indicated.
Comparative Example 7
According to the teaching of DS 193 21 431, a. com-pletely neutralized, poly (sodium acrylate) slightly cross-linked with TMFTA was produced j TS 30% , viscosity 22,700 mPa-s, This product was stirred with 1.5 wt.-% of ethylene clycol bisglycidyl ether, and the change in viscosi-ty was determined. After storing for one hour at room temper-ature, this product already had a viscosity of 27,000 mPa-s, After a 24: hours storage at room temperature, the product was compact, so that the viscosity could not be determined any¬more and processing was made impossible.
Comparative Example 8
A swelling paste was produced using a 30 wt.-% aque-ous solution of a copolymerizate of 30 mole-% acrylic acid, 30 mole-% sodium acrylate and 40 mole-% acrylamide and a viscosity of 7,800 mPa-s, and 2 wt.-% 1,4-butanediol. After coating 0:1 a polyester fabric and crosslinking for two min-utes at 190oC, the dry coating was 10.2 g/m2. The product had a retention of 36,6 g/g, a swelling height after 10 minutes of l.l nun, a swelling height per 100 g of 10.8 mm, and a relative (swelling height after 30 s of 2.94 mm/100 7.
Comparative Example 9
The procedure wae as in Comparative Example 6, but the polymer consisted of 20 mole-% acrylic acid, 20 mole-% sodium acrylate and 60 mole-% acrylamide, and had a viscosity of 14,460 mPa-s at 27% TS. The properties were as follows: dry coating: 12.9 g/m2, retention: 6.9 g/g, swelling height
after 10 minutes: 1.3 mm, swelling height per 100 g: 8.5 mm, relative swelling height after 30 s: 3.1 mm/100 g,
Comarative Example 10
The procedure was as in comparative Example 8, but the polymer consisted of 10 mole-% acrylic acid, 10 mole-% sodium acrylate and 80 mole-% acrylamide., the viscosity was 17,000 mPa-s, and the batch concentration was 22 wt.-%. The properties were as follows j dry coating: 12.7 g/m2/ reten-tion: 9.7 g/g, swelling height after 10 minutes: 1.3 mm, swelling height per 100 g: 10.2 mm, relative swelling height after 30 s: 2,36 mm/100 g.
Comparative Example 11
1,4 wt.-% of 1,4-butanediol and 2,4 wt.-% of penta-erythrito] were added to the polymer solution of example 2 within one 1 hour. After crosslinking (2 minutes, 190'c), the following properties were measured; dry coating: 17.6 g/m , retention: 23.5 g/g, swelling height after 10 minutes: 2,15 mm, Siwelling height per 100 g: 12.2 mm, relative swell-ing height; after 30 s: 2.84 mm/100 g.
1. A swelling paste consisting of an aqueous mixture of
a water-soluble polymer containing carboxyl groups as herein described, constituted by more than 75 mole-% of monomers containing carboxyl groups as herein described, the carboxyl groups thereof being present as a salt to an extent of from 40 to 65 mole-%.,
0.5 to 30 wt-%, based on the weight of the polymer employed, of at least one alkoxylated, multifunctional alcohol as herein described, and
optionally 0 to 30 wt-% of further additives as herein described.
2. The swelling paste as claimed in claim 1, wherein the carboxyl group-
containing polymer is constituted of further water-soluble comonomers as
herein described in addition to the carboxyl group-containing monomers.
3. The swelling paste as claimed in claim 1 or 2, wherein said carboxyl
group containing monomers comprise acrylic acid, methacrylic acid, maleic
acid, maleic anhydride, fumaric acid, itaconic acid, acrylic acid or mixtures
4. The swelling paste as claimed in claim 2 or 3, wherein said water-
soluble comonomers comprise acrylamide, methacrylamide, hydroxyethyl
acrylate, allylsulfonic acid, methallysulfonic acid, and
5. The swelling paste as claimed in one of claims 1 to 4, wherein the 40
to 65 mole-% of the carboxyl groups, which are present as a salt, are
present as Na, K, ammonium, alkylammonium, or alkanolammonium salts.
6. The swelling paste as claimed in one of claims 1 to 5, wherein the
multifunctional alcohols are selected from the groups of ethylene glycol,
propylene glycol, glycerol, butanediol, trimethylolpropane, erythritol,
pentaerythritol, and hydrogenated sugars.
7. The swelling paste as claimed in one of claims a to 6, wherein the
multifunctional alcohols are ethoxylated.
8. The swelling past as claimed in one of claims 1 to 7, wherein the
multifunctional alcohols are ethoxylated using at least 1 mol of ethylene
oxide per mol alcohol, preferably at least 1 mol of ethylene oxide per mol OH
9. The swelling paste as claimed in one of claims 1 to 8, wherein the
carboxyl groups of said water-soluble polymer are present as a salt to an
extent of from 45 to 60 mole-%.
10. The swelling paste as claimed in one of claims 1 to 9, wherein the
multifunctional alkoxylated alcohols is present at a concentration of from 1
to 20, preferably from 1 to 15 wt-%, based on polymer employed.
11. The swelling paste as claimed in claims 1 to 10, wherein additives,
particularly in the form of thickeners, plasticizers, fillers, and dyes are
12. A swelling paste as claimed in any of the preceding claims as and
when, said swelling paste being utilized for the preparation of water-
swellable yarns, fabrics, nonwovens or films.
13. A swelling paste substantially as herein described with reference to
the foregoing examples.
|Indian Patent Application Number||1065/DEL/1998|
|PG Journal Number||13/2009|
|Date of Filing||24-Apr-1998|
|Name of Patentee||STOCKHAUSEN GMBH|
|Applicant Address||25,47805 KREFELD,GERMANY|
|PCT International Classification Number||C08L 39/00|
|PCT International Application Number||N/A|
|PCT International Filing date|