WO1984004098A1 - Copolymerisat greffe d'amidon et d'acrylonitrile a haute capacite d'absorption - Google Patents

Copolymerisat greffe d'amidon et d'acrylonitrile a haute capacite d'absorption Download PDF

Info

Publication number
WO1984004098A1
WO1984004098A1 PCT/SE1984/000127 SE8400127W WO8404098A1 WO 1984004098 A1 WO1984004098 A1 WO 1984004098A1 SE 8400127 W SE8400127 W SE 8400127W WO 8404098 A1 WO8404098 A1 WO 8404098A1
Authority
WO
WIPO (PCT)
Prior art keywords
starch
water
acrylonitrile
acetone
hydrolysis
Prior art date
Application number
PCT/SE1984/000127
Other languages
English (en)
Inventor
Bengt Gustav Raonby
Original Assignee
Bengt Gustav Raonby
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Bengt Gustav Raonby filed Critical Bengt Gustav Raonby
Publication of WO1984004098A1 publication Critical patent/WO1984004098A1/fr

Links

Classifications

    • 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
    • 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
    • C08F251/00—Macromolecular compounds obtained by polymerising monomers on to polysaccharides or derivatives 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
    • C08F8/00—Chemical modification by after-treatment
    • C08F8/44—Preparation of metal salts or ammonium salts

Definitions

  • the present invention relates to a starch derivate with high absorption of aqueous fluids consisting of a water insoluble alkali salt of a in aqueous alkaline hydrolysis medium hydrolized starch-acrylonitrile-graft copolymerisate obtained through graft polymerizing acrylonitrile on granular starch, and a process for the production of the starch derivate.
  • US patent 3 932 322 discloses an improvement with respect to said problem with grain structure and dusting tendency for carboxylate salts of hydrolized starch-acrylonitrile-graftcopolymers. According to this reference the fine-grained copolymer is mixed with certain oxides. Even if a certain improvement of the end product is obtained thereby, the problem of handling a dusting intermediate product before the mixing step is still awkward.
  • a starch derivate of the kind introductively mentioned has been achieved, which complies with the above mentioned claim specification and is primarily characterized in constituting a granulate directly isolated from a hydr lysis medium used for hydrolyzing the graft copolymer, having a water absorption exceeding 150 times its weight and a bulk density less than 0,4 g/cm 3 and being constituted to more than 90 % by weight by porous granule aggregates with a particle size in the range 0,1-1,5 mm.
  • a decisive property of the particles composed by grafted starch granules according to the invention is their open pore structure which results in a relatively low bulk density compared with unmodified starch. This for absorption use desired porosity and the resulting low bulk density create, however, also the above mentioned dusting problem of the above mentioned products.
  • a suitable selection of hydrolysis medium for the hydrolysis of the graft copolymer makes possible the isolation of such aggregates of grafted starch granules, which gives a non-dusting and free-flowing powder with a particle size suitable for practical use and a very rapid liquid absorption.
  • the crucial process step for achieving the highly absorbing starch derivate with suitable grain structure according to the present invention is thus found to be the hydrolysis of the starch-PANpolymer. It is carried out as at previously known hydrolysis by means of an hydroxide of an alkali metal or NH 4 + for transforming the nitrile groups to amide groups and carboxylate groups. An ordinary result of the hydrolysis is that about 30 % amide groups and about 70 % carboxylate groups are obtained. It is also known that the hydrolysis medium except water also must contain another solvent to limit the swelling of the hydrolyzed product. A mixture of water and methanol has up to now been the preferred hydrolysis medium.
  • a hydrolysis medium which except water consists of a lower alcohol, such as methanol or ethanol, and a further, with the alcohol and water mixable solvent, which is more hydrophobic than the alcohol, there is obtained an excellent means to control further aggregation of the granules obtained at the polymerization step. Simultaneously, cracking by overswelling of the starch granules in the aggregates is prevented.
  • the stirring required during the hydrolysis is the stirring only seems to have a marginal effect on the aggregation compared with the selection of hydrolysis medium.
  • acetone due to its volatility and low boiling point and relative innoxiousness seems to be the most suitable alternative.
  • Other water-mixable solvents with similar water affinity as acetone can be used for obtaining non-dusting granules of suitable size directly from the hydrolysis medium.
  • One example is methylethylketone.
  • methylethylketone it has been found that larger amounts of ethanol and methylethylketone compared with methanol and acetone are required to avoid lump formation during the hydrolysis. Since the required amount of alcohol and hydrophobic component seems to be related to molarity, it is realized that amount and costs for these components increase with rising molecular weight.
  • the granular product obtained directly at the hydrolysis step is suitably isolated from the hydrolysis medium through filtration and/or centrifugation.
  • the filtration is facilitated by the fact that the relatively large aggregated granules do not clog the filter.
  • the granules are suitably washed by means of a mixture of alcohol and acetone in e.g. same proportions as used in the hydrolysis step.
  • the acetone proportion can be increased, possibly up to pure acetone, to facilitate the final drying step.
  • the graft copolymerization is carried out in a way known per se by adding to a stirred suspension of starch granules and acrylonitrile under inert gas atmosphere an initiator system known for this purpose at about 30°C.
  • an initiator system known for this purpose at about 30°C.
  • the amount ratio starch/AN is in the range 1:1,5-1:8 mol/mol, while the range 1:2-1:4 in most cases is favourable from economical point of view (the amount of starch is calculated as mol glucose units).
  • the absorption capacity of the product increases rapidly up to a molar ratio starch/acrylonitrile of about 1:3, while with larger proportions of AN rather a small increase in absorption is obtained.
  • a possible, however not verified explanation to the difference in aggregation tendency is that a Mn 3+ -ion, complexed to 2-3 pyrophosphate groups, constitutes a considerable larger complex compared with the Ce 4+ -ion and therefore meets larger resistence against diffusion into the densely packed layers of starch chains in the starch granule.
  • the probability for a higher degree of grafting on the surface of the granules compared with grafting within the granules should therefore increase with the sterical extension of the initiator complex.
  • the product grains obtained directly from the hydrolysis step according to the invention have open pore structure giving a bulk density in the range 0,20-0,40 g/cm 3 , preferably 0,25-0,35 g/cm 3 and consists to at least 90 % by weight of particles with an average particle diameter in the range 0,1-1,5 mm, preferably 0,2-1 mm. Due to said open pore structure and the grain size of the product, good penetration of liquous media is obtained, which makes possible rapid fluid absorption up to almost the full absorption capacity of the product.
  • Starch-PAN-graft copolymers were prepared with a Mn 3+ -pyrophosphate-system as initiator.
  • the hydrolysate prepared in example 7 was filtrated, washed a first time with a mixture of equal parts methanol and acetone and a second time with a mixture of one part methanol and three parts acetone. After that the product was dried and its bulk density was measured to 0,29 g/cm 3 .
  • a sample of the dried product was also studied by means of SEM-technique, and the result of this study is shown in the accompanied pictures of which: Fig. 1 shows a SEM-picture of a number of granule aggregates at 15 times magnification.
  • Fig. 2 shows a SEM-picture of a number of granule aggregates at 50 times magnification.
  • Fig. 3 shows a SEM-picture of a number of granule aggregates at 200 times magnification and
  • Fig. 4 shows a SEM-picture of a number of granule aggregates at 400 times magnification.
  • Fig. 1 and 2 can be seen that the product according to the invention exhibits grains of relatively equal sizes, and the major part of the sample consists of granule aggregates with an average particle diameter of 0,2-0,8 mm.
  • the particle shown in Fig. 3 at 200 times magnification has a length of about 0,4 mm and a width of about 0,2 mm and consists of 200-300 original starch granules. From Fig.
  • the product prepared according to example 7 was examined with respect to absorption of water and synthetic urine.
  • the water absorption was determined by suspending a sample in a certain amount of distilled water, after which the suspension was filtered and the amount of not absorbed water was determined. The amount of retained water was calculated to 276 ⁇ 10 g water/g product.
  • the synthetic urine consisted of 2,04 g K 2 SO 4 , 0,85 g CaCl 2 ⁇ 2H 2 O, 1,14 g MgSO 4 . 7H 2 O, 8,2 g NaCl and 20 g urea in 1000 ml water solution, the pH of which being controlled to 7,0. The amount; retained urine was determined to 44 ⁇ 2 g/g product.
  • 15 g grafted starch prepared according to example 1 was suspended in a solution of 150 ml ethanol and 126 ml methylethylketone, after which a solution of 5,0 g sodium hydroxide in 30 ml water was added.
  • the hydrolysis was carried out in autoclave at 90°C in 2 hours.
  • the obtained product had the form of coarse granules which after washing with ethanol/methyle thy Ike tone and drying in air constituted a non-dusting granulate.
  • the water absorption of the product prepared according to example 14 was determined by suspending a sample in a certain amount distilled water, whereafter the suspension was filtrated and the amount not retained water was determined. The amount retained water was calculated to 256 ⁇ 10 g water/g product . The bulk density was measured to 0,3 g/cm 3 .

Abstract

Dérivé d'amidon à haute absorption de fluides aqueux, se composant d'un sel alcalin insoluble dans l'eau d'un polymérisat d'amidon-acrylonitril-greffe hydrolysé dans un milieu d'hydrolyse alcalin aqueux, obtenu par polymérisation à greffe d'acrylonitrile sur de l'amidon granulaire. En utilisant pour l'hydrolyse un milieu d'hydrolyse contenant de l'eau, un alcool inférieur et un solvant organique mélangeable avec l'eau et l'alcool qui est plus hydrophobe que l'alcool, une substance à structure granulaire ne formant pas de poussière dont la taille des particules est comprise entre 0,1 et 1,5 mm peut être isolée directement du milieu d'hydrolyse. Cette substance granulaire présente d'excellentes propriétés de traitement et est destinée à être utilisée en tant qu'agent d'absorption pour l'eau et les milieux aqueux.
PCT/SE1984/000127 1983-04-08 1984-04-09 Copolymerisat greffe d'amidon et d'acrylonitrile a haute capacite d'absorption WO1984004098A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE8301955A SE8301955D0 (sv) 1983-04-08 1983-04-08 Hogabsorberande ympsampolymerisat av sterkelse och akrylnitril

Publications (1)

Publication Number Publication Date
WO1984004098A1 true WO1984004098A1 (fr) 1984-10-25

Family

ID=20350716

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1984/000127 WO1984004098A1 (fr) 1983-04-08 1984-04-09 Copolymerisat greffe d'amidon et d'acrylonitrile a haute capacite d'absorption

Country Status (2)

Country Link
SE (1) SE8301955D0 (fr)
WO (1) WO1984004098A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0315840A2 (fr) * 1987-11-11 1989-05-17 Politechnika Slaska im. Wincentego Pstrowskiego Méthode de préparation de film d'hydrogel pour pansement
DE19619680A1 (de) * 1996-05-15 1997-11-20 Buna Sow Leuna Olefinverb Gmbh Verfahren zur Herstellung von superabsorbierenden Polymeren auf Stärkebasis

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3932322A (en) * 1975-03-07 1976-01-13 Kimberly-Clark Corporation Water absorbing starch-acrylonitrile graft copolymers fumed silica or alumina modified to improve rate of absorption for physiological fluids
SE387123B (sv) * 1970-05-18 1976-08-30 Grain Processing Corp Forfarande for framstellning av ett alkalimetallkarboxylatsalt av en sterkelse-polyakrylnitrilymppolymer eller en sterkelse-polymetakrylnitrilymppolymer
US4028290A (en) * 1975-10-23 1977-06-07 Hercules Incorporated Highly absorbent modified polysaccharides

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE387123B (sv) * 1970-05-18 1976-08-30 Grain Processing Corp Forfarande for framstellning av ett alkalimetallkarboxylatsalt av en sterkelse-polyakrylnitrilymppolymer eller en sterkelse-polymetakrylnitrilymppolymer
US3932322A (en) * 1975-03-07 1976-01-13 Kimberly-Clark Corporation Water absorbing starch-acrylonitrile graft copolymers fumed silica or alumina modified to improve rate of absorption for physiological fluids
US4028290A (en) * 1975-10-23 1977-06-07 Hercules Incorporated Highly absorbent modified polysaccharides

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0315840A2 (fr) * 1987-11-11 1989-05-17 Politechnika Slaska im. Wincentego Pstrowskiego Méthode de préparation de film d'hydrogel pour pansement
EP0315840A3 (fr) * 1987-11-11 1991-03-06 Politechnika Slaska im. Wincentego Pstrowskiego Méthode de préparation de film d'hydrogel pour pansement
DE19619680A1 (de) * 1996-05-15 1997-11-20 Buna Sow Leuna Olefinverb Gmbh Verfahren zur Herstellung von superabsorbierenden Polymeren auf Stärkebasis

Also Published As

Publication number Publication date
SE8301955D0 (sv) 1983-04-08

Similar Documents

Publication Publication Date Title
CA1109052A (fr) Compositions polymeres hautement absorbantes, a partir de copolymeres de greffe de polymeres polyhydroxyles
US5498678A (en) Suspension polymerization process for water-soluble monomers
US4045387A (en) Highly absorbent polymeric compositions derived from flour
US4340706A (en) Alkali metal acrylate or ammonium acrylate polymer excellent in salt solution-absorbency and process for producing same
US5350799A (en) Process for the conversion of fine superabsorbent polymer particles into larger particles
US4385164A (en) Block copolymer dispersion stabilizer and aqueous dispersion polymerization therewith
CA2045425C (fr) Poudres superabsorbantes renfermant de la silice, procede de preparation et application
CA2125084A1 (fr) Procede de polymerisation d'une dispersion
JPS5823801A (ja) 懸濁重合法
JPH0377202B2 (fr)
US4777232A (en) Method of manufacturing polysaccharide graft polymers which absorb water and are capable of swelling
GB2207140A (en) Process for production of highly water-absorbent resin
US2783212A (en) Cross-linked copolymers of an acrylic acid as cation exchanging resins
US4190718A (en) Process for increasing molecular weight of vinylpyrrolidone polymer
JPS61502543A (ja) ポリマ−物質およびその製造
JPS643884B2 (fr)
KR860001409B1 (ko) 비이드상 폴리머의 제조법
WO1984004098A1 (fr) Copolymerisat greffe d'amidon et d'acrylonitrile a haute capacite d'absorption
US2963453A (en) Acrylic and methacrylic acid resins controllably crosslinked with polyallyl acrylate, its substituted derivatives, and copolymers thereof
CA2098658A1 (fr) Polyacrylonitrile poreux pyrolyse
US4221684A (en) Absorbent polymeric compositions derived from corn flour and starch
JPS6295308A (ja) ビ−ズ状高吸水性ポリマ−の製造方法
US4355157A (en) Hot water precipitation of resins containing maleic anhydride
US3879363A (en) Polymerisation process
JPS61200102A (ja) 吸水性樹脂の製造法

Legal Events

Date Code Title Description
AK Designated states

Designated state(s): DK FI JP NO US

AL Designated countries for regional patents

Designated state(s): AT BE CH DE FR GB LU NL SE

WA Withdrawal of international application