EP0000426A1 - Latex amphotères et procédé pour leur préparation - Google Patents

Latex amphotères et procédé pour leur préparation Download PDF

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Publication number
EP0000426A1
EP0000426A1 EP78300090A EP78300090A EP0000426A1 EP 0000426 A1 EP0000426 A1 EP 0000426A1 EP 78300090 A EP78300090 A EP 78300090A EP 78300090 A EP78300090 A EP 78300090A EP 0000426 A1 EP0000426 A1 EP 0000426A1
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EP
European Patent Office
Prior art keywords
latex
acid
group
monomer
amphoteric
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.)
Ceased
Application number
EP78300090A
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German (de)
English (en)
Inventor
Robert Owen James
Andrew Marian Homola
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University of Melbourne
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University of Melbourne
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Publication date
Application filed by University of Melbourne filed Critical University of Melbourne
Publication of EP0000426A1 publication Critical patent/EP0000426A1/fr
Ceased legal-status Critical Current

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    • 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
    • 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
    • C08F246/00—Copolymers in which the nature of only the monomers in minority is defined

Definitions

  • This invention relates to improved latices and more particularly to improved synthetic latices which show amphoteric properties.
  • various synthetic latices which are produced by polymerisation of monomers such as styrene, butadiene, methyl methacrylate, ethyl acrylate, vinyl acetate, vinyl chloride, vinylidene chloride and certain mixtures of these mononers.
  • latices have been formed in one of two ways. These arc that the stabilisation is due to electrostatic repulsion between surfaces with adsorbent surfactants and/or due to steric replusion (steric stabilisation) due to the presence of polymer chains with or without fixation or anchoring moietes at the latex surfaces.
  • Sterically stabilised latices may also have functional groups as part of or attached to the particles which groups are normally of the same charge and thus there is also a charge stabilisation acting to prevent coagulation.
  • Electrostatically and/or sterically stabilised latices normally have an overall negative charge although positively charged latices are known. Although latices are widely used in industry, they can be unsatisfactory in that the surfactant is normally charged and can often be preferentially absorbed onto a surface or can compete for charged particles on a surface with the latex particles.
  • latices The other major form of latices are the so-called surfactant free latices which may in fact contain a quantity of surfactant stabilised latex and in this case the main mechanism for stabilisation lies in the repulsion because of the similar charges on the various particles.
  • These latices have conventionally had an overall negative charge although positively charged latices are known. To the best of our knowledge,.there has been no disclosure in the literature of amphoteric latices and certainly we know of no disclosure of surfactant free amphoteric latices.
  • the invention includes an amphoteric latex characterised in being formed by co-polymerising monomeric polymerisable compounds including a base monomer and two further monomers one including an amine group (R 3 NH + ) and the other a carboxyl group (RCOOH) by the use of a polymerisation catalyst, the latex having ionisable amine and carboxyl groups on the surfaces thereof.
  • polymerisable monomers including an amine group is selected from:-
  • the monomer containing the carboxyl group may be selected from:-
  • the latices may be formed using a styrene monomer as the base monomer but, alternatively, they may be formed using other monomers such as methyl methacrylate, ethyl acrylate, vinyl acetate, vinyl chloride, vinylidene chloride and certain mixtures of these and other monomers, for example a mixture of styrene and butadiene monomers.
  • the amine used was N,N-Diethylaminoethyl methacrylate and the carboxyl was methacrylic acid.
  • the polymerisation catalyst can satisfactorily be potassium persulphate.
  • other initiators, including y-radiation can equally well be used.
  • the optimum pH for minimum coagulation is pH 1.2.
  • the particle size of the latex can be controlled by controlling the concentration of monomers in the solution.
  • Latices which have the same properties, particularly iso-electric point and surface charge but which are of different sizes can be made. It is necessary to increase the concentration of the monomers in the solution with a further increase in the proportion of monomers which have functional groups to compensate for the increase in surface area to maintain a required charge density.
  • Latices made in accordance with the invention can be of one of two forms, either hard latices or soft latices.
  • Hard latices are used for a number of applications, particularly in coating fine papers and in certain medical applications where they can be carriers for radioactive isotopes and, because of the differences in cell structures, so the isotopes can selectively be delivered to such areas. Once delivered a scan or the like can be made and the distribution of the isotopes determined.
  • Soft latices are used in paints and when the paint is drying the latices tend to form a hard transparent film incorporating pigment and filler, thereby providing the outer surface of the paint.
  • the latices are to be placed on a surface which is negatively charged and it has often been necessary to use an intermediate so that the latex is not repelled by the material on which it has been located.
  • adjustment of the pH can cause variations in the surface charge and the latex may selectively exhibit positive or negative characteristics depending on which side of the iso-electric point it is located at the particular pH value.
  • the actual iso-electric point can be varied by variation of the proportion of carboxyl to amine and thus where one is constrained to operate at a certain pH the surface charge of the latices can still, within limits, be controlled.
  • the amine or the carboxyl acid is deactivated so the growing particles all exhibit the same charge and, as such tend to repel so that there is little coagulation during growth.
  • the deactivated functional group can be reactivated and the required properties of the latex are revealed.
  • KPS Potassium persulphate
  • the materials were poured into a 273 cc capacity container purged with nitrogen (- 10 min) sealed and tumbled end-over-end (- 50 rpm) in a water bath at 70°C for a specified time. At the end of the reaction time the latex was decanted through a filter packed with glass wool in order to remove any coagulum formed.
  • any other form of mixing vessel in which an inert atmosphere can be maintained can be used.
  • the latex suspension contained (in addition to copolymerised amine and carboxylate groups) some potassium sulphate, sulphuric acid, hydrochloric acid, unreacted monomer, and possibly some soluble copolymers.
  • the latex was dialysed against distilled water, using well- boiled Visking dialysis tubing, until the specific conductivity of the diaylsate was lower then 2 x 10 -6 mho can -3 ; thus usually required about 10 changes of water over a period of two weeks.
  • the ratio of dialysate to latex used was -50 to 1.
  • the latex particles were sedimented by centrifugaticn at 2.5 x 10 4 g for one hour. The supernatant was then discarded and the latex cake was redispersed with slightly acidified distilled water (pH3). This procedure was repeated 10 times.
  • the electrophoretic nobilities of the latices were measured by the microelectrophoretic technique.
  • the apparatus employed is manufactured by Rank Bros.
  • the mobility values were converted into zeta potentials, following the known Wiersema et al treatment. Titration of surface groaps
  • the pH was measured using a combined glass-calomel electrode and a Radiometer (Copenhagen) pM 26 meter.
  • the electrodes were calibrated with Merck Titrisol buffer solutions of pH 4.00 ⁇ 0.02 and 9.00 ⁇ 0.02 at 20°C.
  • the conductance was measured by a Wayne-Kerr conductance bridge assembly.
  • the titrations were carried out on 100 cm 3 diluted samples of purified latex in a thermostatted glass container at 20°C.
  • the latex was stirred with a magnetic stirrer and carbon dioxide was excluded by passing a stream of nitrogen over the latex surface.
  • the titration cell had a tight- fitting cap with sockets to accept the ground glass cones on the combined electrode, the conductivity cell, the micrometer syringe tip and nitrogen inlet.
  • a weighed amount of latex ( ⁇ 1 g) was diluted to 100 cm 3 with distilled water in a thermostatted glass container. Both sets of electrodes of the pH meter and the conductance bridge were placed in the diluted latex dispersion. Mechanical stirring of the latex was started and the pH of the latex sample was adjusted to a pH of 2.5 ⁇ 0.1 with dilute HCl solution. The sample was then titrated with standard 1 N/l KOH in 0.02 ml increments by means of a micrometer syringe fitted with a glass needle.
  • the latex suspension B, prepared at pH 1.2, has an excellent stability, with the axception of the pH region near the iso-electric point, and consists of highly monodisperse particles with the average diameter of 185 nm. Samples A, C, D and E varied in a degree of uniformity, as shown in the last column of Table l; however, no significant deviations from the average particle size of the latex E were noted.
  • the level of amine was set at 1.0 g and the molar ratio of acid to amine was increased approximately from zero to 2. The results are listed ii, Table 3.
  • the location of the iso-electric point shifted toward the higher pH (Fig. 1) as the acid/amine ratio was decreased.
  • the average particle size (185 nm) was found to remain basically unchanged although monodispersity was affected and was the highest for equimolar acid and amine monomers, (J).
  • the electrophoretic mobility of latex B was measured in various constant ionic strength solutions, i.e. 10 -3 , 10 -2 and 10 -1 mol dm -3 NaCl, as a function of pH.
  • the results are shown in Fig. 3.
  • the zeta potential-pH values are fairly symmetrical about the pH iep , suggesting similar magnitude of surface charge on the cationic and anionic surfaces.
  • the data shown in Fig. 2 at 5 x 10 -2 mol dm -3 HaCl show the same pH iep and the magnitude of the zeta potential lies between the values at 10 -2 and 10 -1 mol dm -3 NaCl.
  • latex in the pH range 6-7.5, coagulated readily but it was subsequently redispersed fully when pH was changed to lower or higher values.
  • a sample of latex left coagulated for several days showed the same trend. This may well be because of a very high charge residing on the particle surface.
  • the functional groups responsible for the surface charge are sulphate and carboxylate.
  • Organic sulphates approximate strong acid behaviour with intrinsic acidity constants characterised by pK a ⁇ 2.
  • Lat ices with sulphate surface groups are essentially completely.ionised in slightly acidic and neutral solutions. In this case, conductometric titration is more satisfactory than potentiometric titration as potentionetric titration ehdpoint is rather difficult to detect with high accuracy.
  • Latices with carboxylate surface groups may be usefully characterised by both conductometric and potentiometric titration. The methods are really complementary.
  • the conductometric titration endpoints indicate the amounts of excess strong acid or base and the total surface charge without detailing the pH dependence of the surface charge or the surface dissociation constants. If the endpoints are known from either conductometric or potentiometric titration, then the potentiometric titration yields information on the fractional ionisation and dissociation constants as a function of pH. Where conductometric titration is not carried out simultaneously, the endpoints may be found using Gran's method.
  • the titration data for amphoteric latex B are shown in Fig. 4.
  • the cationic and anionic sites are not distinguished by endpoints in the conductometric titration. Two endpoints are observed, at 0.460 and 0.680 ml corresponding to the titration of excess strong mineral acid and then the total ionisable protons from weak acid groups. Further addition of strong base serves merely to increase the OH" concentration and the conductance increases more rapidly.
  • the conductometric titrations give no clue as to the relative amounts of -RCOOH and -R 3 NH + groups:
  • the total number of ionisable surface sites is given by 0.220 x 10 -3 moles/0.8277 g of latex. Using the specific surface area 30.9 m 2 /g this corresponds to 83.2 ⁇ Coul/cm 2 of protonic charge.
  • the potentiometric titration shows only one clear inflexion at about .56 ml and pH 6.8. If, however, Gran's method is applied to the pH-volume results, endpoints are obtained at 0.464 and 0.670 ml in reasonable agreement with the conductometric results. On the other hand, when Gran linearisation plots are attempted for data points between the excess strong acid and excess strong base endpoints, the Gran functions are non-linear with volume. Thus, the endpoint for the titration of carboxylic acid groups alone cannot be determined.
  • this latex is unique in two respects, (1) the sign of the surface charge is controlled by pH, and (2) the magnitude of the charge that can be developed, ca ⁇ 40 ⁇ C/cm 2 , is higher than negatively charged surfactant free sulphonated or carboxylate latices.
  • This latex also has the unusual property that it is easily redispersed after coagulation by simply altering the solution pH so as to charge the surface.
  • the high magnitude of the charge and consequently high surface potential must cause sufficient electrostatic repulsion to overcome the van der Waals attractive forces.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
EP78300090A 1977-06-27 1978-06-27 Latex amphotères et procédé pour leur préparation Ceased EP0000426A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU576/77 1977-06-27
AU57677 1977-06-27

Publications (1)

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EP0000426A1 true EP0000426A1 (fr) 1979-01-24

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EP78300090A Ceased EP0000426A1 (fr) 1977-06-27 1978-06-27 Latex amphotères et procédé pour leur préparation

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AU (1) AU3747378A (fr)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997031042A1 (fr) * 1996-02-23 1997-08-28 The Dow Chemical Company Revetements a base aqueuse reversible et irreversible
WO1998052698A1 (fr) * 1997-05-23 1998-11-26 The Dow Chemical Company Revetements et formulations de latex a fixage rapide
US5910532A (en) * 1997-05-29 1999-06-08 The Dow Chemical Company Multisolvent-based film-forming compositions
US5959016A (en) * 1997-07-31 1999-09-28 The Dow Chemical Company Composition for preparing a solvent-resistant coating
WO2000008077A1 (fr) * 1998-08-07 2000-02-17 Reichhold, Inc. Nouvelles compositions a base de latex destinees a etre deposees sur divers substrats
US6191211B1 (en) 1998-09-11 2001-02-20 The Dow Chemical Company Quick-set film-forming compositions
WO2001074919A1 (fr) * 2000-04-01 2001-10-11 Qinetiq Limited Polymeres
US7781498B2 (en) 2003-07-03 2010-08-24 Mallard Creek Polymers, Inc. Cationic latex as a carrier for bioactive ingredients and methods for making and using the same
US7981946B2 (en) 2003-07-03 2011-07-19 Mallard Creek Polymers, Inc. Antimicrobial and antistatic polymers and methods of using such polymers on various substrates
US9220725B2 (en) 2006-08-24 2015-12-29 Mallard Creek Polymers, Inc. Cationic latex as a carrier for bioactive ingredients and methods for making and using the same
US11134684B2 (en) 2005-08-24 2021-10-05 Purdue Research Foundation Method of using hydrophilized bactericidal polymers
US11421084B2 (en) 2017-05-27 2022-08-23 Poly Group LLC Dispersible antimicrobial complex and coatings therefrom
US11680116B2 (en) 2017-06-16 2023-06-20 Poly Group LLC Polymeric antimicrobial surfactant

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3404114A (en) * 1965-06-18 1968-10-01 Dow Chemical Co Method for preparing latexes having improved adhesive properties
FR2182060A1 (fr) * 1972-04-26 1973-12-07 Basf Ag
FR2186497A1 (fr) * 1972-05-31 1974-01-11 Ici Australia Ltd
GB1407116A (en) * 1973-01-17 1975-09-24 Commw Scient Ind Res Org Preparation of amphoteric ion exchange resins

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3404114A (en) * 1965-06-18 1968-10-01 Dow Chemical Co Method for preparing latexes having improved adhesive properties
FR2182060A1 (fr) * 1972-04-26 1973-12-07 Basf Ag
FR2186497A1 (fr) * 1972-05-31 1974-01-11 Ici Australia Ltd
GB1407116A (en) * 1973-01-17 1975-09-24 Commw Scient Ind Res Org Preparation of amphoteric ion exchange resins

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997031042A1 (fr) * 1996-02-23 1997-08-28 The Dow Chemical Company Revetements a base aqueuse reversible et irreversible
WO1998052698A1 (fr) * 1997-05-23 1998-11-26 The Dow Chemical Company Revetements et formulations de latex a fixage rapide
US6251485B1 (en) * 1997-05-23 2001-06-26 The Dow Chemical Company Fast-setting latex coatings and formulations
US5910532A (en) * 1997-05-29 1999-06-08 The Dow Chemical Company Multisolvent-based film-forming compositions
US5959016A (en) * 1997-07-31 1999-09-28 The Dow Chemical Company Composition for preparing a solvent-resistant coating
WO2000008077A1 (fr) * 1998-08-07 2000-02-17 Reichhold, Inc. Nouvelles compositions a base de latex destinees a etre deposees sur divers substrats
US6359110B1 (en) 1998-09-11 2002-03-19 The Dow Chemical Company Quick-set film-forming compositions
US6191211B1 (en) 1998-09-11 2001-02-20 The Dow Chemical Company Quick-set film-forming compositions
JP2003529649A (ja) * 2000-04-01 2003-10-07 キネテイツク・リミテツド ポリマー
GB2376020A (en) * 2000-04-01 2002-12-04 Qinetiq Ltd Polymers
WO2001074919A1 (fr) * 2000-04-01 2001-10-11 Qinetiq Limited Polymeres
GB2376020B (en) * 2000-04-01 2004-09-29 Qinetiq Ltd Polymers
US7112639B2 (en) 2000-04-01 2006-09-26 Qinetiq Limited Polymers
US7781498B2 (en) 2003-07-03 2010-08-24 Mallard Creek Polymers, Inc. Cationic latex as a carrier for bioactive ingredients and methods for making and using the same
US7981946B2 (en) 2003-07-03 2011-07-19 Mallard Creek Polymers, Inc. Antimicrobial and antistatic polymers and methods of using such polymers on various substrates
US11134684B2 (en) 2005-08-24 2021-10-05 Purdue Research Foundation Method of using hydrophilized bactericidal polymers
US11459415B2 (en) 2005-08-24 2022-10-04 Purdue Research Foundation Method of using hydrophilized bactericidal polymers
US9220725B2 (en) 2006-08-24 2015-12-29 Mallard Creek Polymers, Inc. Cationic latex as a carrier for bioactive ingredients and methods for making and using the same
US11421084B2 (en) 2017-05-27 2022-08-23 Poly Group LLC Dispersible antimicrobial complex and coatings therefrom
US11760844B2 (en) 2017-05-27 2023-09-19 Poly Group LLC Dispersible antimicrobial complex and coatings therefrom
US11680116B2 (en) 2017-06-16 2023-06-20 Poly Group LLC Polymeric antimicrobial surfactant

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Publication number Publication date
AU3747378A (en) 1980-02-21

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