emulsions/latices theory/types• latex/emulsion is the name given to the widely used binder in...

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MPMA One Day SeminarWater Based Paints An Overview :

Part 6:

EMULSIONS/LATICESTHEORY/TYPES

September 15 2015


INTRODUCTION• LATEX/EMULSION IS THE NAME GIVEN TO THE

WIDELY USED BINDER IN DECORATIVE WATERBASED PAINTS

• A LATEX IS A STABLE DISPERSION OF A POLYMERIN WATER

• IT CAN BE CONSIDERED AS MILLIONS OF PLASTICSPHERES DISPERSED NOT DISSOLVED IN WATER


LATEX FILM FORMATION-1

Continuous Polymer Coating

Water evaporation +polymer deformation

Close Packed Spheres withWater Filling Voids

Aqueous DispersionDepositedon Surface

Water evaporation


LATEX FILM FORMATION 2• YOU CAN SEE FROM THE ABOVE THAT WHEN A

LATEX FORMS A FILM THE INDIVIDUAL POLYMERPARTICLES COALESCE TO FORM A CONTINOUSPOLYMER FILM–SO IT CHANGES IT’S PHYSICALNOT CHEMICAL STATE AND THERE FORE LATICESARE NON CONVERTIBLE POLYMERS


LATEX FILM FORMATION 3• ONE OF THE MOST IMPORTANT LATEX

PROPERTIES IS IT’S MINIMUM FILMING FORMINGTEMPERATURE (MFFT)

• MFFT IS THE TEMPERATURE AT WHICH THE LATEXJUST FORMS A CONTINIOUS FILM

• AT A TEMPERATURE BELOW IT’S MFFT THE LATEXWILL NOT FORM A CONTINIOUS FILM AND ACRACKED OR POWDERY LAYER WILL RESULT


LATEX FILM FORMATION 4• MFFT ALSO GIVES AN INDICATION OF FILM

PROPERTIES AS WELL• A LOW MFFT POLYMER WILL BE MORE FLEXIBLE

BUT ALSO POSSIBLY RETAIN MORE DIRT• A HIGHER MFFT POLYMER WILL BE LESS DIRT

RETENTIVE BUT ALSO LESS FLEXIBLE, IT WILLALSO BE MORE ABRASION RESISTANT


LATEX FILM FORMATION 5• HERE IN SEA WHICH IS A HOT CLIMATE WE TEND

TO FAVOUR MEDIUM TO HIGH MFFT LATICES (18-30DEG C) IN THE HOPE THAT WE WILL GET SOMEFLEXIBILITY BUT ALSO LOW DIRT RETENTION

• IN ORDER TO GET GOOD EARLY FILM FORMATIONESPECIALLY UNDER COOLER HUMID CONDITIONSWE ADD A COALESCENT OR TEMPORARYPLASTICISER TO LOWER THE INITIAL MFFT


COALECENTS 1• COALESCENTS ARE HIGH BOILING POINT

SOLVENTS THAT SOFTEN THE POLYMER SHELLAND EFFECTIVELY TEMPORARILY LOWER MFFT SOTHE LATEX/PAINT CAN FORM A FILM AT A LOWERTEMPERATURE

• ONCE THE COALESCENT HAS DONE ITS JOB ITEVAPORATES AND LEAVES THE FILM


COALESCENTS 2• HERE IN SEA WE AIM TO REDUCE THE MFFT TO

BELOW 10 DEG C• OBVIOUSLY THE AMOUNT OF COALESCENT

REQUIRED DEPENDS ON THE ORIGINAL MFFT OFTHE POLYMER HOWEVER FOR MOST COMMONLYUSED LATICE IN SEA WORK ON 7-10% ON BINDERSOLIDS LEVEL, HOWEVER FOR SOME NEWERLOWER VOC POLYMERS USE 2-5% AND FOR SOMEVERY HARD POLYMERS 10-15% IS REQUIRED


COALESCENTS 3• ALTHOUGH MANY HIGH BOILING SOLVENTS CAN

BE USED AS COALESCENTS. IN OUR REGION WETEND TO USE NX795/TEXANOL, WHICH IS BOTHCOST AND PROPERTY EFFECTIVE WITH A WIDERANGE OF LATEX TYPES . IT HAS A BOILING POINTOF 254 DEG C WHICH MEANS AT PRESENT IT ISNOT CLASSED AS A VOC IN THE EU


COALECENTS 4• IN THE EU/USA OTHER VERY HIGH BOILING POINT

LOWER ODOUR COALESCENTS ARE BEINGOFFERED E.G. NX 800, OPTIFILM 300/400, FX510AND COASOL A ETC

• THEY ARE MORE EXPENSIVE THANNX795/TEXANOL AND ARE NOT THAT WIDELY USEDYET IN DEVELOPING MARKETS


OTHER REQUIREMENTS OF A POLYMERFOR PREMIUM PAINTS 1

• Durability and maintaining it’s sheen after long periods ofexterior exposure



• Water whitening/blanching• It would be no good if a dark coloured

paint turns, white/ lighter in colour whenheavy rain impinging on it



• Water resistance• Excellent water resistance will not only stop blanching

but also help with wet adhesion and partially withFungus/algae resistance (we would still recommend Theaddition of a Dry Film Biocide)



• If a polymer is APEO free it will not onlyhelp the environment but also improvelong term water resistance as well, asAPEOS remain in the film



• Resistance to Chalking- if a binder begins to break downon UV exposure-too quickly then the under bound fillerspresent can wash out of the film and deposited on thesubstrate below

• Styrene Acrylic binders tend to chalk far more quicklythan Pure Acrylics or VA Veova's/VA VEOVATerpolymers



• Efflorescence resistance- also called frosting• If a polymer doesn’t have inherently good efflorescence

resistance –white patches will begin to be seen in 1-2years

• PA/SA/V/Veova Terpolymers better than VA/Veova

PA VA/Veova


OTHER REQUIREMENTS OF A POLYMERFOR SHEEN PAINTS 7

• Low Dirt pick up or high dirt pick upresistance (DPUR)

• Is a function of MFFT and hydrophobiscitybut it can be dramatically improved byusing Microvoid Opacifiers like RopaqueUltra E/HIQUE/Orgawhite Etc.



• A polymer should associate well but nottoo well with HEUR or HASE typethickeners- but if too much HASE typethickeners are required cost and waterresistance are adversely effected



• Although some people may disagree we feel that it couldbe essential that a premium paint be able to adhere toa range of commonly used substrates, with the minimumamount of surface preparation both in the dry and afterre wetting (heavy rain etc.) – non adhesion promotedPure Acrylics- tend to get give good adhesion under drybut not wet conditions. Adhesion promoted pure acrylicsperform extremely well under both dry and wetconditions


LATEX TYPES 1• PURE ACRYLICS WERE FIRST PRODUCED BY R+H

IN THE MID 1950’S• THEY COMBINE OUTSTANDING DURABILITY AND

ALKALI RESISTANCE WITH EASE OFFORMULATION STAIN AND WATER RESISTANCE

• THEY CAN BE PRODUCED IN THE FOLLOWINGTYPES:


LATEX TYPES 2• PURE ACRYLIC ADHESION PROMOTED SELF

CROSS LINKING LATICES E.G. PRIMAL HG 98 ™,HG 415 ™ LDM7450/60 REV 815

• HAVE OUTSTANDING DURABILITY, ALKALI ANDBLOCKING RESISTANCE AS WELL AS ADHESION TOA WIDE RANGE OF SUBSTRATES (ESPECIALLY OLDALKYD)

• WIDELY USED IN WATER BASED GLOSS, SEMIGLOSS


LATEX TYPES 3• ADHESION PROMOTED PURE ACRYLICS WHICH

HAVE OUTSTANDING DURABILITY, ALKALI /STAINRESISTANCE AND EXCELLENT WET AND DRYADHESION TO A WIDE RANGE OF SUBSTRATESINCLUDING METAL, MASONARY AND WOOD ANDARE USED IN A WIDE RANGE OF PREMIUMPRODUCTS (SHEENS/MATT, ROOF PAINTS ANDVARNISHES/CLEAR COATS)


LATEX TYPES 4• NON ADHESION PROMOTED PURE ACRYLICS ARE

ONE OF THE WORK HORSES OF THE RSA PAINTINDUSTRY THEY ARE USED IN A WIDE RANGE OFPRODUCT TYPES, THEY HAVE EXCELLENTDURABILITY, ALKALI AND STAIN RESISTANCE

• WIDELY USED IN SEA FOR SHEEN/LOW SHEEN,MATTS ROOF PAINTS AND SOMETIMES TEXTUREDFINISHES


LATEX TYPES 5

• In SEA like many other DevelopingMarkets VA VEOVA TERPOLYMERS arevery popular for High/Medium and lowQuality Paints

• This is because although they may not bethe best Polymer for every use they arevery versatile allowing smaller Paintcompanies to offer a range of products byjust keeping one polymer type


LATEX TYPES 6

• HOWEVER FOR HIGHER PVCPRODUCTS, SOME TEXTURES ANDWATER PROOFING END USESEXPERIENCE HAS SHOWN THATSTYRENE ACRYLIC POLYMERS GIVENTHE BEST BALANCE OF PROPERTIESAND COST

• THE ONLY ISSUE IS WHICH ONES


LATEX TYPES 7

• FOR FLEXIBLE TEXTURES AND WATERPROOFING END USES SOFT STYRENEACRYLICS (MFFT 6-12 DEG C)DOMINATE

• THEY HAVE THE COMBINATION OFHYDROPHOBICITY/FLEXIBILITYREQUIRED WATCH OUT FOR SHEARINSTABILITY YELLOWING ANDCHALKING


LATEX TYPES 8

• FOR HIGH PVC PRODUCTS HIGHERMFFT (16-20) DOMINATE WITH FINEPARTICLE SIZE, SURFACTANTSTABILISED POLYMERS BEING THEORDER OF THE DAY

• WATCH OUT FOR YELLOWING ,CHALKING AND BRITTLENESS AS THEMFFT GETS ABOVE 20 DEG C

LATEX TYPES 9

• Nano Particle sized Latices are beginningto be seen here in Developing Marketsone of the First Examples is LDM2801from Archroma is a Nano VA VeovaTerpolymer that is being used in Low VOCWB Plaster Primers that can be packed inStandard Plastic Containers



CONCLUSIONS

• LOTS OF CHOICE BUT PICKCAREFULLY A SHORT TERM SAVINGCAN LEAD TO AN EXPENSIVE LONGTERM MISTAKE

emulsions/latices theory/types• latex/emulsion is the name given to the widely used binder in...

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