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
  • C08F299/00—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers
  • C08F299/02—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates
  • C08F299/04—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates from polyesters
  • C08F299/0485—Macromolecular compounds obtained by interreacting polymers involving only carbon-to-carbon unsaturated bond reactions, in the absence of non-macromolecular monomers from unsaturated polycondensates from polyesters from polyesters with side or terminal unsaturations
• • 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
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium

Definitions

• This invention relates to aqueous dispersions of polymer for use in surface coatings and adhesives and more particularly to such dispersions wherein the particles comprise autoxidisable polymers.
• Autoxidisable polymers that is polymers which will crosslink on exposure to oxygen, have been known for many years and have been used extensively in the surface coatings industry.
• the autoxidisable species which have almost universally been used are the long chain unsaturated fatty acids derived from naturally-occurring triglyceride drying oils; there are other autoxidisable species such as vinyl dioxolane, dicyclopentadiene, certain poly(butadienes) and certain allyl group-containing entities, but the drying oil-derived species have hitherto remained the most widely used.
• multi-polymer particles I mean particles of film-forming polymer comprising at least two polymers, at least one of these polymers (the "in situ polymer”) being formed in the presence of at least one other polymer (the "pre-formed polymer”).
• the in situ polymer the polymers
• the pre-formed polymer the polymer which is formed in the presence of at least one other polymer.
• Such dispersions promise considerable versatility in the formulation of coating compositions - it may often be possible to obtain coating films with the advantageous properties of several polymers.
• the general method of preparation of such particles is to dissolve or disperse at least one pre-formed polymer in ethylenically unsaturated monomer, disperse the solution thus formed in water and then polymerise the monomer to form an aqueous dispersion of multi-polymer particles.
• multi-polymer particles can be found in, for example, British patents 1,417,713, 1,421,114 and
• an autoxidisable film-forming material which comprises an aqueous dispersion of particles of film-forming polymer, the particles comprising at least one chemical compound which comprises at least two autoxidisable groups and polymer formed by the addition polymerisation of ethylenically unsaturated monomer, the dispersion additionally comprising at least one stabilising compound for the particles, characterised in that
• the material of the disperse particles comprises from 0.2 - 35% by weight of the said autoxidisable groups
• the said groups comprise at least 20% of the total number of autoxidisable groups present in the material of the particles;
• CH 2 CR-CH 2 -O- where R is H or CH 3 ;
• the material of the disperse particles comprises from 0.2 - 35% by weight of the said autoxidisable groups
• the abovementioned groups comprise at least 20% of the total number of autoxidisable groups present in the material of the particles; and (f) where the stabilising compound is amphipathic, it is free of ethylenic unsaturation.
• More than one (meth)allyloxy group-containing chemical compound may be present.
• Such chemical compounds may also comprise reactive groups capable of reaction with, for example, a cross-linking agent, the polymer formed in situ or other polymer.
• the chemical compound prefferably comprises autoxidisable groups other than the (meth)allyloxy groups, provided that at least 20% of the total number of autoxidisable groups shall be (meth)allyloxy groups and that such groups shall comprise from 0.2 - 35% (preferably 1-10%) by weight of the material of the disperse particles.
• the polymer particles may also comprise at least one polymer which is distinct from both the in situ polymer and the chemical compound and which does not comprise (meth)allyloxy groups. I have found that when the chemical compound is non-polymeric or non- oligomeric in nature, it is preferable that the particles include such polymer.
• the polymer may be chosen from a wide range of polymers known to the art and the choice is restricted only by the extent to which such polymer can contribute desirable properties to the final dispersions.
• the polymer may be convertible or non-convertible; it may comprise, for example, reactive groups for crosslinking by reaction with a cross-linking agent, the chemical compound, other polymer or the in situ polymer.
• autoxidisable group is a molecular entity with the capacity to undergo autoxidation.
• each fatty acid chain is considered to be a single autoxidisable group even though it may comprise up to three ethylenic double bonds.
• the monomer from which the in situ polymer is formed may be selected from one or more the wide range of ⁇ , ⁇ -ethylenically unsaturated monomers known to the art.
• Typical examples of monomers which can be used in our invention are methyl, ethyl, propyl, butyl, allyl, lauryl and stearyl acrylates and methacrylates, styrene, the mixed isomers of methyl styrene known as "vinyl toluene", vinyl chloride and vinyl acetate and di-alkyl maleates.
• Functional monomers such as hydroxy-propyl methacrylate and acrylic and methacrylic acids may also be used if, for example, it is desired to provide the ability for the in situ polymer to react with another entity such as pre-formed polymer, a cross-linking agent or a chemical compound as hereinabove described.
• the film-forming disperse polymer particles of my invention comprise a blend of in situ polymer, chemical compound and, if present, other polymer.
• the particles may not be just simple mixtures of ingredients; it is possible (and indeed often desirable) that during the addition polymerisation reaction in which the in situ polymer is formed, there is also a degree of reaction of the (meth)allyloxy groups of the chemical compound with the monomer forming the in situ polymer.
• this reaction never occurs to such a degree that it removes the autoxidation capacity from the dispersions.
• the chemical compound present in such a system to be within the scope of my invention although it may not be present in its original form.
• stabilising compound is not critical to the performance of my invention and a suitable compound can be freely selected from the wide variety known to the art, with the exception that when the stabilising compound is amphipathic, it must also be free from ethylenic unsaturation.
• Stabilising compounds comprising ethylenic unsaturation have been long known and widely used in connection with non- aqueous dispersion systems, but have relatively recently been used in aqueous sytems. Examples of such stabilising compounds may be found in European Published Application No. 0 002 252. However, it is a requirement of my invention that the amphipathic stabilising compounds for use therein be entirely free of ethylenic unsaturation.
• a stabilising compound suitable for use in my invention can be selected from a wide variety of commercially-available materials. It may be, for example, an amphipathic compound lacking ethylenic unsaturation as hereinabove described. Typical examples include commmercially-available ionic and non-ionic surfactants. Non-ionic surfactants include compounds such as octyl and nonylphenol ethoxylates, for example, the "Teric" (trade mark) and "Triton” (trade mark) series.
• Ionic surfactants may be cationic (such as various commercially-available quaternary ammonium compounds) or anionic (such as sulphated natural oils, long chain fatty acid soaps and various isopropyl naphthalene sulphonates, sulphosuccinates and sulphosuccinamates).
• the stabilising compound need not be an amphipathic compound but may be selected from the group of known suspending agents and colloid stabilisers. Examples of these include poly(vinyl alcohols), various watersoluble cellulose derivatives such as the hydroxyalkyl celluloses and complex polysaccharides such as gum tragacanth.
• the stabilising compound is typically present to the extent of 0.1 - 20.0% by weight of the total weight of the material of the particles.
• the dispersions of my invention may be prepared by any convenient means.
• One method which may be used is the preparation of a suitable dispersion of polymer particles, followed by the addition thereto of chemical compound.
• a further method is the preparation of a bulk polymer incorporating chemical compound followed by the dispersion thereof in water by any suitable means.
• my preferred method is the method used by the art to form multi-polymer particles, that Is, the polymerisation of unsaturated monomer in the presence of another component. I find this to be the best method because of its convenience and its versatility; it may be used with a very wide range of materials.
• One preferred process for preparing the dispersions according to my invention comprises the steps of mixing chemical compound, monomer, stabilising compound and water so as to form a dispersion of particles wherein the individual particles comprise a blend of chemical compound and monomer, and then polymerising the monomer.
• the formation of the initial dispersion of monomer-chemical compound particles may be achieved simply by adding the chemical compound and monomer separately to water whilst stirring.
• my preferred method is to blend the chemical compound with the monomer and then to disperse the blend in water. It is preferable that the chemical compound and the monomer be compatible but this is not essential and in some of my systems they are relatively Incompatible.
• the stabilising compound may be added either to the water or to the chemical compound and/or monomer.
• a useful variant of these methods is the addition of the chemical compound and a portion of the monomer to the water and the initiation of polymerisation, the remainder of the monomer being fed into the mixture during the course of the polymerisation. All of the foregoing is also applicable to cases where it is desired to add other polymer.
• Free radical addition polymerisation may be initiated by any of the means well known to the art.
• I can use a free radical initiator such as azobisisobutyronitrile.
• I can also use a redox initiation system and polymerisation can be conveniently initiated at room temperature.
• the nature of the redox initiation system to be used depends to some extent on the natures of the polymer and monomer but selection of a suitable system is within the knowledge of the art. Typical examples of suitable systems are t-butyl perbenzoate/sodium ascorbate and cumene hydroperoxide/sodium ascorbate.
• the initiation systems may be oil-soluble systems, and the result will be a suspension (mini-bulk) polymerisation. It is also possible to use watersoluble initiation systems.
• the nature of the polymerisation involved in this case is not completely known to me but I believe without restricting my invention in any way that the chemical compound is transported to the forming particles by monomer which is migrating to micelles formed by the stabilising compound in the manner of a conventional emulsion polymerisation.
• cumene hydroperoxide/sodium ascorbate system hereinabove described can be used in this fashion as cumene hydroperoxide is partially soluble in water, but I prefer to use a persulphate salt such as ammonium persulphate; such salts are widely used in emulsion polymerisations.
• a persulphate salt such as ammonium persulphate
• aqueous dispersions prepared by the process of this invention may be used in a number of applications. They may, for example, be used as the film-forming components of coating compositions. Conventional additives such as pigments, extenders, thickening agents and fungicides may be added in art-recognised quantities.
• a polyester resin prepared from allyl glycidyl ether, adipic acid and isophthalic acid in the molar ratio of 1.4:0.5:0.5 polymerised to an acid value of 8 mg KOH/g.
• a non-ionic stabiliser prepared by reacting bisphenol A with 16 moles of propylene oxide which is in turn reacted with 54 moles of ethylene oxide.
• the materials A were mixed and warmed to dissolve the stabilising compound. A was then cooled to room temperature and B was added. When B was dissolved the mixture was added to C under high speed mixing and diluted with D. The dispersion had a maximum particle diameter of 1.5 ⁇ m.
• Polymerisation was carried out by heating the dispersion to 60°C for 4 hours and to 80°C for a further 2 hours, the dispersion being stirred continuously to dissipate the heat evolved.
• Example 1 Preparation and testing of an aqueous polymeric dispersion wherein the (meth)allyloxy groups comprised 2.5% by weight of the polymeric dispersion.
• the procedure of Example 1 was repeated except that 5.8 parts of polyester, 32.8 parts of methyl methacrylate and 18.6 parts of butyl acrylate were used in place of the quantities of Example 1.
• Example 2 Polymerisation was carried out as for Example 1 to give a white dispersion. This gave a film which was xylene solvent resistant after the film was aged for 4 hours at 50°C.
• Example 1 The procedure of Example 1 was repeated except that 34.8 parts of polyester, 12.7 parts of methyl methacrylate, 7.3 parts of butyl acrylate and 0.1 parts of azo-bls-iso-butyronitrile were used in place in the quantities of Example 1.
• Example 2 Polymerisation was carried out as for Example 1 to give a white dispersion. This formed a film which was xylene solvent resistant after 3 hours at 25°C.
• Example 1 Polymerisation was carried out as for Example 1 to give a white dispersion. This produced a film which was xylene solvent resistant after the film had aged for 3 hours at 50°C, or 48 hours at 25°C The time to develop xylene solvent resistance at 25°C is more than 10 times longer than in Example 3 where the chemical compound was polymeric, even though the allyloxy content in Example 4 was higher than in Example 3.
• EXAMPLE 5 Preparation and testing of an aqueous polymeric dispersion wherein the chemical compound is monomeric and the particles also comprise a polymer which is free from meth(allyloxy) autoxidisable groups.
• polyester 1 12.5 A methyl methacrylate 16.0 butyl acrylate 13.1 nonyl phenol ethoxylate 3.1 stabilising compound
• Polyester composition 1,6 hexane diol (2.5 moles); fumaric acid (1.15 moles) and adipic acid (0.85 moles); condensed to an acid value of 5 mg KOH/g of polyester.
• the materials A are premixed and added to B under high speed mixing to form a fine oil-in-water emulsion which is then diluted with C.
• D is premixed and added to the fine emulsion resulting in polymerisation of the emulsion.
• polymerisation E is added slowly with stirring, followed by the addition of F. This dispersion was then drawn down to form a film which developed xylene resistance in one hour at 50°C. In the absence of either the polyester or the monomeric pentaerythritol triallyl ether, xylene resistance had not been attained after 3 hours at 50°C.

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• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Polymerisation Methods In General (AREA)
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• 1983
  • 1983-06-24 EP EP19830901886 patent/EP0112346A4/de not_active Withdrawn
  • 1983-06-24 WO PCT/AU1983/000082 patent/WO1984000169A1/en not_active Application Discontinuation
  • 1983-06-24 JP JP58502130A patent/JPS59501165A/ja active Pending
  • 1983-06-28 ZW ZW147/83A patent/ZW14783A1/xx unknown
  • 1983-06-29 ZA ZA834769A patent/ZA834769B/xx unknown

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