Polyolefin elastomers boost end use performance of hot...
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T he global adhesives mar- ket accounted for 24bn lb in 2013*, with hot melt adhesives (HMA) accounting for 15%, making it the third largest segment behind water-based and solvent-based adhesives. The HMA market is highly fragment- ed and includes more than 10 end-user applications, such as packaging, non-woven, pressure sensitive adhesive and book bind- ing, as well as furniture and con- struction applications. A RAPIDLY EVOLVING MARKET THAT BRINGS ITS OWN CHALLENGES The development of the global hot melt adhesives industry is being driven by a number of evolving trends. Packaging indus- try brand owners and adhesive formulators are faced with the complex challenge of meeting end-user demands for food safe- ty, while ensuring the shelf appeal, cost efficiency and sus- tainability of their solutions. Changes in consumer demo- graphics, notably as the popula- tion ages, are adding factors, such as enhanced wear and comfort to the growing list of demands in the hygiene market. The resulting relentless increase in the demand from adhesives formulators and brand owners for high-performance solutions that deliver new and improved application and per- formance properties, is driving suppliers to deploy their efforts to boost the end use performance of their hot melt adhesives solutions and, in doing so, providing a response to those challenges. POLYOLEFIN-BASED ELASTOMERS DELIVER PERFORMANCE FOR HMA Polyolefin elastomer (POE)-based HMA give excellent performance by surpassing EVA-based HMA for- mulations in three main categories: processability, adhesive perform- ance and reduced total cost. PROCESSING POE-based HMAs deliver improved processing because of their better thermal stability, result- ing in char-free and clean applica- tion equipment. The low or no gel formation reduces the applicator downtime and gives a consistent adhesive application, resulting in improved running costs and reduced scrap. There is also less wear and tear on the equipment, primarily due to the lack of acidity of the base polymer compared to EVA resulting in extended lifetime of filters and nozzles. Additionally, the ease of cleaning from machin- ery and the lack of angel hair result in more savings through reduced labour costs. ADHESIVE PERFORMANCE POE-based HMAs are better adhesives. Due to their low initial colour and good thermal stability of POE the end HMA has better colour compared to alternatives, as well as a lack of odour, thus making them a great fit for both packaging and hygiene applica- tions. POE-based HMAs can also be applied on a variety of surfaces and, due to the lower density and viscosity, they can provide great adhesion, even if the POEs may not contain any polar functionality. ENHANCED TOTAL COST Overall, POE-based HMAs give the formulators and brand owners and packers improved mileage and lower maintenance for a better total cost and performance com- pared to EVA-based HMAs. Due to the improved thermal stability and lower density of Affinity GA POE-based HMAs, the mileage advantage can bring up to 30% saving. Also no need to change nozzles and filters for Affinity GA POE-based HMAs resulted in a significant decrease in downtime of machines compared to EVA- based HMAs again bringing addi- tional operational cost saving. PO-BASED ELASTOMERS MEET HMA MARKET NEEDS The Dow Chemical Company was the first to introduce polyolefin- based copolymers into hot melt adhesive formulations some 15 years ago. Since then, this HMA for- mulation produced with Dow’s Insite Technology, has demonstrated signif- icant advantages compared to the use of traditional EVA-based HMAs. The first introduced polyolefin- based polymer family was ethyl- ene-octene random copolymers with the brand name of Affinity GA POE (figure 1).These random copolymers combine low crys- tallinity and low density (≤0.887 g/cc) with a very low viscosity. Due to Dow’s Insite Technology, poly- mer architecture can be precisely controlled, so that the optimum balance of the necessary amor- phous properties and strength can be achieved. Thanks to the higher HOTMELT TECHNOLOGY Polyolefin elastomers boost end use performance of hot melt adhesives Dr Burçak Conley, Dr Allan McLennaghan and Dr Selim Yalvac, Dow Elastomers, look at the growing market need for hot melt adhesives 34 EAS – December 2014 www.coatingsgroup.com Author: Dr Burçak Conley, Technical Service and Development Manager, Dow Elastomers, Bachtobelstrasse 3, 8810 Horgen, Switzerland. [email protected]; Dr Allan McLennaghan, Senior Technical Service & Development Specialist, Dow Elastomers, Bachtobelstrasse 3, 8810 Horgen, Switzerland. [email protected] Dr Selim Yalvac, Senior Research and Development Manager, Dow Elastomers, Texas Operations, 2301 Brazosport Blvd, Freeport, TX 77541-3257 USA. [email protected]; www.dowelastomers.com Fig 1. Affinity GA POE structure Source: *DPNA, Kusumgar
Transcript of Polyolefin elastomers boost end use performance of hot...
The global adhesives mar-ket accounted for 24bn lbin 2013*, with hot melt
adhesives (HMA) accounting for15%, making it the third largestsegment behind water-based andsolvent-based adhesives. TheHMA market is highly fragment-ed and includes more than 10end-user applications, such aspackaging, non-woven, pressuresensitive adhesive and book bind-ing, as well as furniture and con-struction applications.
A RAPIDLY EVOLVINGMARKET THAT BRINGS ITSOWN CHALLENGESThe development of the globalhot melt adhesives industry isbeing driven by a number ofevolving trends. Packaging indus-try brand owners and adhesiveformulators are faced with thecomplex challenge of meetingend-user demands for food safe-ty, while ensuring the shelfappeal, cost efficiency and sus-tainability of their solutions.Changes in consumer demo-graphics, notably as the popula-tion ages, are adding factors, suchas enhanced wear and comfortto the growing list of demands inthe hygiene market.
The resulting relentlessincrease in the demand fromadhesives formulators and brand
owners for high-performancesolutions that deliver new andimproved application and per-formance properties, is drivingsuppliers to deploy their efforts toboost the end use performance oftheir hot melt adhesives solutionsand, in doing so, providing aresponse to those challenges.
POLYOLEFIN-BASED ELASTOMERS DELIVERPERFORMANCE FOR HMAPolyolefin elastomer (POE)-basedHMA give excellent performanceby surpassing EVA-based HMA for-mulations in three main categories:processability, adhesive perform-ance and reduced total cost.
PROCESSINGPOE-based HMAs deliverimproved processing because oftheir better thermal stability, result-ing in char-free and clean applica-tion equipment. The low or no gelformation reduces the applicatordowntime and gives a consistentadhesive application, resulting inimproved running costs andreduced scrap. There is also lesswear and tear on the equipment,primarily due to the lack of acidityof the base polymer compared toEVA resulting in extended lifetimeof filters and nozzles. Additionally,the ease of cleaning from machin-ery and the lack of angel hair resultin more savings through reducedlabour costs.
ADHESIVE PERFORMANCEPOE-based HMAs are betteradhesives. Due to their low initialcolour and good thermal stabilityof POE the end HMA has bettercolour compared to alternatives,as well as a lack of odour, thusmaking them a great fit for bothpackaging and hygiene applica-tions. POE-based HMAs can alsobe applied on a variety of surfacesand, due to the lower density andviscosity, they can provide greatadhesion, even if the POEs maynot contain any polar functionality.
ENHANCED TOTAL COSTOverall, POE-based HMAs givethe formulators and brand ownersand packers improved mileage andlower maintenance for a bettertotal cost and performance com-pared to EVA-based HMAs. Dueto the improved thermal stabilityand lower density of Affinity GAPOE-based HMAs, the mileageadvantage can bring up to 30%saving. Also no need to changenozzles and filters for Affinity GAPOE-based HMAs resulted in a
significant decrease in downtimeof machines compared to EVA-based HMAs again bringing addi-tional operational cost saving.
PO-BASED ELASTOMERSMEET HMA MARKET NEEDSThe Dow Chemical Company wasthe first to introduce polyolefin-based copolymers into hot meltadhesive formulations some 15years ago. Since then, this HMA for-mulation produced with Dow’s InsiteTechnology, has demonstrated signif-icant advantages compared to theuse of traditional EVA-based HMAs.
The first introduced polyolefin-based polymer family was ethyl-ene-octene random copolymerswith the brand name of AffinityGA POE (figure 1). These randomcopolymers combine low crys-tallinity and low density (≤0.887g/cc) with a very low viscosity. Dueto Dow’s Insite Technology, poly-mer architecture can be preciselycontrolled, so that the optimumbalance of the necessary amor-phous properties and strength canbe achieved. Thanks to the higher
HOTMELT TECHNOLOGY
Polyolefin elastomers boost end useperformance of hot melt adhesives
Dr Burçak Conley, Dr Allan McLennaghan and Dr Selim Yalvac, Dow Elastomers,
look at the growing market need for hot melt adhesives
34 EAS – December 2014 www.coatingsgroup.com
Author:Dr Burçak Conley, Technical Service and Development Manager, Dow Elastomers, Bachtobelstrasse 3, 8810 Horgen, Switzerland. [email protected];
Dr Allan McLennaghan, Senior Technical Service & Development Specialist, Dow Elastomers, Bachtobelstrasse 3, 8810 Horgen, Switzerland. [email protected] Selim Yalvac, Senior Research and Development Manager, Dow Elastomers, Texas Operations, 2301 Brazosport Blvd, Freeport, TX 77541-3257 USA.
[email protected]; www.dowelastomers.com
Fig 1. Affinity GA POE structure
Source: *DPNA, Kusumgar
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levels of incorporated octene co-monomer, the glass transition tem-peratures of these polymers arelower than those of EVA gradesused in HMA formulations. Thismakes the polymers more suitablefor low temperature HMA appli-cations (figure 1).
Since then, new classes of poly-olefin-based elastomers have beendeveloped through Dow’sadvanced knowledge in InsiteTechnology to precisely controlthe molecular architecture of thepolymers. One such breakthroughwas Infuse Olefin BlockCopolymers (OBC) produced by‘chain shuttling technology’. Theseblock polymers contain semi-crys-talline ‘hard blocks’ and elastomer-ic ‘soft blocks’, making them uniqueas POEs. The hard blocks provide ahigh melting temperature, whilethe soft segments maintain theoverall polymer elastic properties.
Among key differencesbetween Infuse OBC and StyrenicBlock Copolymers (SBC) are:� SBCs are typically polymerised byliving anionic polymerisation condi-tions with a narrow molecularweight distribution (Mw/Mn≈1.0-1.5) resulting in monodisperseddiblocks or triblocks. � OBCs are produced with chainshuttling technology and have amultiblock structure of alternatinghard and soft blocks with a molec-ular weight distribution (Mw/Mn≈2). Examples from Dow areInfuse OBC and Intune OBC (fig-ure 2).
Last but not least, among thematerial types are propylene-eth-ylene random copolymers, mar-keted by Dow under the brandname of Versify Plastomer andElastomer (figure 3).
A DIFFERENTIATEDAPPROACH TO ADDRESSDIVERSE PACKAGINGTRENDS Among key trends driving the devel-opment of adhesives for the packag-ing segments are the following: � High to low temperature adhe-
sion performanceIn line with the lifestyle
demands of today’s consumers,food packages are exposed to dif-ferent temperature conditionsfrom high temperature (eg hot fillor pasteurisation) down to verylow temperature (eg frozen food).HMA formulators are directingefforts towards developing adhe-sives for this evolving markettrend, which will hold the packageunder a wide range of tempera-ture conditions by giving increasedpackaging security.
The success of Dow AffinityGA-based HMA at low tempera-ture can be attributed to the lowTg of Affinity GA providing ductili-ty at low temperatures (figure 4).However, if formulators are look-ing for solutions pushing the limits,one possible approach is to addInfuse OBC 9807 into the HMAformulation. The hard blocks inInfuse will provide additional fibretear at high temperature, while thesoft blocks will give low tempera-ture bond flexibility (figure 4).� High speed packaging linesWith an eye on cost effectiveness,the industry is moving towardsnew manufacturing lines offeringfaster speeds. The HMA is expect-ed to hold the package even aftera short set time.
By using XUS 38614.00 anExperimental Polyolefin Plastomer(0.887g/cc with 1000 MI) materialfrom Dow with a slightly higherdensity and crystallinity comparedto Affinity GA 1900 (0.870 g/ccwith 1000 MI) the HMA formula-tion will have additional strength ata shorter set time (figure 5) – thusfacilitating a fast bond formation.� Hard-to-bond surfacesEither because of a focus on shelfattractiveness or to achieve cer-tain barrier properties, it has beenchallenging to ensure adherenceof some substrates to the boards,known as ‘hard-to-bond’ surfaces.Typical examples of hard-to-bondsurfaces are PET, BOPP or coatedKraft papers.
In order to improve the adhe-
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35 EAS – December 2014 www.coatingsgroup.com
Fig 2. Above: Infuse OBC structureFig 3. Below: Versify elastomer structure
Fig 4. Fibre tear at different temperatures
Fig 5. Fibre tear vs set time
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sion performance, Dow has devel-oped MAH functionalised ethyl-ene-octene copolymer : AffinityGA 1000R. This material will pro-vide additional strength to differ-ent substrates which are ‘hard-to-bond’ due to the polar groups(Table 1).
KEY HYGIENE TRENDSThere are also a number of criticaltrends affecting the developmentof HMA for the hygiene segment,including the need for reliable andsecure feedstocks. In addition, thedemanding customer base is look-ing for solutions that deliver :� Low odourCustomers want high qualitymaterials that avoid unpleasantodours. When POE-based adhe-sives are used with the same tack-ifier as SBC, they provide betterodour characteristics (figure 6). � Colour and ageingThe market increasingly demandssolutions that deliver improvedcolour and viscosity stability overtime. Ethylene-based polyolefin
elastomers offer improved colourand viscosity stability (figure 7).
DOW WORKS WITH CUS-TOMERS TO PROVIDE ASTRONG RESPONSE TOMARKET NEEDSAs has been seen, brand ownersand adhesives formulators arefaced with an increasingly complexand demanding marketplace. DowElastomers is the ‘go-to’ innovationpartner, delivering high perform-ance solutions that provide cus-tomers with a strong response totheir needs. The broad range ofDow’s POE solutions combinesperformance criteria with cost effi-ciency and sustainability, thus cre-ating a sustainable differenceacross the value chain.
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Table 1. Fibre tear on different substrates measured at a different temperature
Fig 6. Odour rating of PO-based HMA vs SBC-based HMAFig 7. Above right: Colour and ageing of OBC-based HMA vs SBC-based HMA
AFFINITY, INSITE, INFUSE, INTUNE,
VERSIFY are Trademarks of The Dow
Chemical Company (‘Dow’) or an
affiliated company of Dow
Odour Rating
0 = no odour, 5 = very strong odour
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