WO2014074115A1

WO2014074115A1 - Hot melt adhesives

Info

Publication number: WO2014074115A1
Application number: PCT/US2012/064494
Authority: WO
Inventors: Steven R. Wann; Mark K. JONES; Daniel T. Carraway
Original assignee: Danimer Scientific, Llc
Priority date: 2012-11-09
Filing date: 2012-11-09
Publication date: 2014-05-15

Abstract

The present disclosure provides a hot melt adhesive composition which includes at least the following components: (1) from about 8 to about 50 weight percent of a lactic acid oligomer or polymer having a number average molecular weight of loss than about 2000; (2) from about 10 to about 50 weight percent of polylactide having an enantiomeric purity of at least about 95 mole percent; (3) from about 0.25 to about 8 weight percent of an aliphatic amide having from 8 to 50 carbon atoms; (4) from about 10 to about 40 weight percent of a terpene phenolic tackifier; and (5) from about 5 to about 20 weight percent of polyvinyl acetate. Ail of the aforementioned weight percentages are based on the overall weight of the hot melt adhesive. An adhesive-coated substrate and a method for applying a hot melt adhesive to a substrate are also disclosed.

Description

MOT MILT ABIIIS! VES

FIELD iMJ The pm it dlseiosire laes m &sa! to ot melt adhesive md m artic lar to hot melt adheslves having improved *¾hl£ life" as well as Mgh conest of biodegradable c m onents, reeyekbk oo∞po:aent% and/or c m o eats ©btssked fmm tm b natural r sources..

2J Hot melt adhesives a e used corsmeraaliy to bond a wide variety of substra es, A principal advan a e of hot melt adbeslves is dieir leek of a lipoid earner in the adhesive com os ti n. Without a liquid carrier, there is no need for a dr ing period after application so that production line s eds oaa be Increased, in situations where organic sol e ts are used as^' liquid carriers, their elmhiatioa reduces environmental md humaa risks associated with their s . ilhiainatioa of fee liquid carrier also reduces the weight ami bulk: of the adhesive tor shipping and storage,

|W3| Hot. melt adhesives ate typically melted and to. held molten for a period of time ia a heated vessel at a ternperature close to the application temperature for the adhesive. The period of time the ad esive is held in a molten state may range from just a few hours to as lon as several < s< For bet melt sdhesives derived from petrolenni-hased components, this extended beatin time poses few problems for the Inte y of t e adhesive before and after application_* Components* of petroleum-based adhesives are generally quite resistant to degrad tion at hot melt application tem e atu es. Further_* m applied, the bond formed In the glued article is also resistant to degradation react ns {e,g._:> o;dda†io»_s hydrol sis and emwrnatie) that might be encountered during the article's useful life. Thus pctroieum-based adbesives ha e both long "po life'* and impart long shel life" to the substrates they hind,

|W4| N n heless, it Is still desirable to incorpomte biodegradable, reeyek e, and/or renewable components mto hot melt adhesive compositions due to environmental and heaidr concerns. However, tor ad esive® derived from components that are reuewahle, recyclable and ot biodegradable, the polymeric components that give the adhesive its strength and the bond durability over time have been foun to be susceptible to the degradation. reactions noted above both during the application period and after a bond lias formed. Moreover, "side" reactions between these and other components of the adhesive composition turther erode the adhesive⁵ s strength by ejecting a reduction In moieenkr weight As a result, hot melt adbe ives derived from renewable components generally exhibit a feirlv short ^**pot life⁵* md the glued article often is before the article's service iim«. Consequ t!^ there have to date been few, if aay, commercially a cess s pllcat tis of such hot melt adfeeswn, fM>Sj It would t eeoe be advantageous t provide a hot melt adhesive composition ^•whic incor orate a high content of biodegradable, recycla l , aod/er renewable o©i¾ >oems, hut whieb ¾Iso exhibits impsived pot life and/or shelf life as compred to earlier hot. melt adhesive compositions.

OM A V io^'f hi a fern mj t, the preseul disclosure rvdes a hoi taeli adhesive <^m s c«L A^cordmg to ne embodiment, the hot melt adhesive includes at least the JM!owmg oompoaeats: (!) itoaa about S to abo 50 weight perceai of a lacbc sold oligomer or po!ymer having a omaher average Kdeeekr weight of less ihau about 20 (2) from ahoat 10 to abou SO weight pereeat of po!ylaetide having m eaantlome lo parity of at least about 1 mole owrs; (3) t¾>»r about 0,25 to aboat S -weight percent ©f n alplmde amide having from. S to SO earboa aoms; aod (4) from about 5 to about 20 weight pecen of polyvinyl acetate. All of the afor emeatloaed weight ercenages are based oa the overall mi ht of the hot roeit adhesive.

IWfy la oae eadx>dlreeat of the hot melt adhesive, the aliphatic amide is preferably selected from the group cousisdag of ste ramide, beheoatrside, d^'-^hyl oe-bis-I^- hydrojrseatamlde, ami tmxtmes iieteof More preferably_* the aliphade amide is ^'Μ,Ν*» ei!^^~ ^t2¾d siearam e<

In eertala eaihodimeats of the hot melt ahesive, the porylactide has aa L» esas ajer½ puri ty of at least abou 95 m ole percent

[e j la eertala e bodiments, the hot melt adhesive also ioeludes Ifora. about 10 to about 40 weight percent of a eordensatloa copolymer formed from the eopolymeri¾atioa of a dloi aad a. dkaxh xyltc add. la general, the condensation copolymer preferabl has a melting poiat mperatue of at least about 70 degrees€> More preferably, the co !a&saden copolymer has a raeiiing ierrrperature of at least about 100 degrees C> la some embodmeat of die hot melt adhesive, the condensation copolymer k preferably selected from, the grcmp consisin of polypropyie e femamte, po!yheyiefie f½aarate, pofyhexyleae fumarate, p lyhoiyteue sueeuate,. polyethylene oxalate, poiy(l,4« dlmehylol cyclohexyl} oxalate, nd mixtures thereof More preferably the eoadeaaadoa eopoiyaier is polypropyleue fumarate, polybutyieae sueuinate, or a mixture thereof. [ il in o e embodiment of the hot molt adhesive, the hot melt adhes e preferably has m nitial visc sity from about 1 ,000 to about 10,000 eP at a temjmature of shout 18) degrees C> Mens preferably, the hot melt adhesive preferably has an initial viscosity ifom about 3,000 about 7,<KK⁾ eP at a temperature of about lOO degrees C

According to certain emfe<xime» s of the hot melt adhesive, the aliphatic amide refe ably m a melting temperature of at least about SO degrees C More preferably, the aliphatic amide has a melting temperature of at le st about 90 degrees C. 0ISJ In some embodimen _* the hot melt adhesive also includes from about 10 to about 40 weight percent of a terpeoe phenolic t&ck er. The terpeme phenolic taokifier preferably has a glass transition temperature of at least about 65 degrees€<

|t!41 In some embodinieuts of the hot melt adhesive, it is preferred, that at least about 51 wig t pe cen of the components of the hot melt adhesive are biodegradable, recyclable, and/or .renewable,

In one embodiment of the hot melt adhesi ve, the adhesi ve when applied to a substrate, preferably has a peel test temperature of from about 60 to abo ut 153 degr es C and retains su Seient bond strength to retna bonded to the suhsirate for at least one year_*

I» a second aspect, the present disclosure provides an. adhesive-coated substrate. According to oae em im nt_* the adhesive-coated substrate includes a substrate having at least a first side; and a hot melt adhesive eoatiog applied to at least of portion of the substrate ifrst side. The hot meli adhesive includes at st die Mowing c m onents: (I) from about S to about SO weight percent of a lactic acid oligomer or polymer having a umbe average molecular weight of less than about 2000; (2) from about 10 to about 50 -weight percent of polylaehde having an enantiomeric purity of at least about 95 mole percent; (3) from about 0.2.5 to about 8 weight percent of an aliphatic ami de having from 8 to 50 carbon atoms; and (4) from about 5 to about 20 weight percent of po vi yl acetate. All of the aforementioned weight percentages are based on the overall weight of the hot .melt adhesive. The substrate preferably Includes a paper or paperfeoard material [ 1?1 In sa e bodlmesa of me adhesive-coaed s bsrae, the aliphatic amide is preferably selected t rn the group eonsisfmg of stearamide, belm¾a lde N_? '-eth k¾e- s->i2dtyd«s siearamide, and mixtures thereof More preferably, the aliphatic amide is 5 ^!»e t iooo« is 2-hydr ysieaam «;. fO!Sj In certain em!xdiment of the adhesive-eoatod substrate,, the polylactide has an L» esaoti mede parity of at last about 5 mole percent, ff Iff hi e «a½ embodments of the adhesive-coated substr in, the hot melt adhsi e also trom about 10 to out 40 weight percent of a co densation copolymer

!omw from the eopoiyrnad¾lon of a dioi d a die&rboxylle dd. In general the condensation mpoi a preferably has a meMag point temperature of mi least about 70 degrees€, M re preferably, the condmtatt ft copolymer has a melting tempera re of at least about 100 degrees C.

(439) In some embodiments of the: adhesive<-coated substrate, the condensation copolymer ½ preferably selected from the group consisting of polypro lene femarate,. poiybutytene faanmste, potyhexylene femarae* polyhotyieoe sudnate, polyethylene oxalate, po!y(l_y4-diroethylol eyelohexyi) oxalate, and mixtures thereof, oe preerabl , the condensation copolymer s polypropylene Oimarate, poi hutykme soeeirado, or a mixture thereof

|¾2I| In erje embodiment of the adhesiye-eoated substrate, the hot melt adhesive preferably has m mltial viscosity t¼m about 1,000 to about 1 ,000 eP at a temperatue of about 160 degrees C. More preferably, the hot melt adhesive preferably has art initial viseosity from ab ut 2,000 to alxrai 7,000 cP at a temperawe of about 100 degrees <1

[0221 According to certain embodimeata of the adhesive-eonted substrate, th aliphatic amide preferably has a roeltmg temperature of at least about SO degrees C. More preferably, the aliphatic amide has a melthsg temperature of at least about 90 degrees C

£023) in some embodiments of the adhesive^coated substrate, the hot melt adhesive also includes fam about 10 to about 40 weight percnt of a terens phenolic taekirler. The terpens phenolic taekl&r preferably has a glass transition temperature of at least about 65 degrees€, More re&mbly_^ the terpene phenolic taektfier has a glass t nsition

of at least a out 80 degrees; C, 0241 *^β s me embodiments of the adhesive-elated substrate, it is preferred tha at least about 51, weight percent of the components of the hot melt adhesive are biodegradable, recyclable, and/or renewable, 02Sj ne em odim n of the adhesive-coated substrate, fee adhesive whea applied to a snbstrate,. preferably ag a peal test termj raiure of .from ab ut 60 to about 153 grees C and retaks s« ieat feoad strength to remain bonded to the substrate for at least ne year. l&M] In yet another aspect, t e promt disclosure provides a method for applying ¾ hot mel adhesive to a substrate_* According to one embodiment the method includes the steps of providing hot melt dhesiv and appb/ing fee hot melt adhesive to at leas a portion of at least one sid« nf a substrate, According to the method, the hot melt dhesiv includes at least the follo ing components: (I) fmm about 8 to about 50 weight percent of a lactic acid oligomer or polymer haviug a msmber average molecular weight of less than about 2000; (2) from about 10 to abooi 50 weight percent of polylaetide having an enantiomeric purity of at least about 95 mole percent; (3) from about 0,25 to about 8 weight percent of an aliphatic amide having fmm 8 to 50 carbmi atoms; and (4) from about 5 to about 20 weight percent of polyvinyl acetate.. All of the aforemeuuoned weight percentages are b sed on the overall weight of the hot melt adhesive. The substrate prefe abl includes a paper or paperboard material f#2^'7] In one emb dimm of the method, the aliphatic amide is preferably selected from the group consisting of steuramide, heheuamide, N_? '~ethyleno"bis-!2~ hydmxystearamide, and mixtures thereof More preferably, the aliphatic amide is N,1>P*

| 28f certain embo iments of the method, the poiylaetkie has an L~enantiomerie purity of at least about 95 mole percent. 2 J eertam embodiments of the Bjeihod, the hot melt adhesive $$ includes rom about 10 to about 40 weight ejreent of a ei detm km copolymer, formed from the eopolymerissatioa of a djol as<$ a dlcarbox lk ac d. In. ene al, the eoa easatioa copolymer preferably has s& melting point tempemtee of least about 70 degrees C. Mote- preferably_* the eondeo tioo. copolymer has a meltkg temperature of at least about 100 A rees C

[^§S0| Irs. some «mhod »»^ of the me hod, the condensation copolymer is preferably selected from the group coexistin of polypropylene fe te, polybmyiene &marate_s polybexylet¾e fm nuate, p lybuiylene mari te, polyethylene oxalate, poly(i_»4~ dimethy l eyclohexyl) oxalate, mi m mm thereof More preferably* the condensation copolymer olypro lene fuorarate, potybu yk-ne anockate, or a mixture the eof

[^§311 In one emb diment of the method, the hot melt adbestw preferably has initial viscosity f om about 1,000 to about 10,000 eF at a temperature of about 160 degr es (I More preferably, the hot melt adhesive preferably has a initial v sc sity from, about 2,000 to about 7,000 eF at a teoperaturo of about 160 degrees C»

|0321 According to certain emhodhnents of the method, the aliphatic amide pmfer bly has a melting !emp mtore of at least about 50 degrees C, More preferably, the aliphatic m de has a melting temperature of at least about 90 degrees C.

|0331 Irs some embodiments of the method, the hot melt adhesive also includes from about 10 to about 40 wei ght percent of a terpeae phenolic taekiikr. The terpene phenolk taofciiier preferably has a glass traasitlon. temperature of at least about 6$ degrees€» More preferably, the ter erte phenolic taek er has a glass transition temperature of at least about SO degrees CL

| 34| In some embod men s of the method, it is preferred that at least about 51 weight percent of the components of the hot .melt adhesive are blodegradahle_f recyclable, ami/or reoewab - |03SJ In <zm «m odme¾l of x* method, &■ telvs wb aplied to a ssu r&ie_* preferably has a peel test tempemiure of tea abou 60 to abcmt 153 de ees C and retains suffik l bom! strength to rgsm&ia cm¼d to t e- su str te for k<m o wr.

DlTAILll) D&SCRSFT IO 3#) ^'The present discl sure provides a hot molt adhesive com osition. According to tks present disclosure, the ad esi e eomposltior generally Includes at least he following oompoa ms: (1 ) from about 8 to about SO weight p^roem of a ketie acid oligomer or polymer having a mimher average molecular weight of less than about 2000; (2) from about 10 to a bo a! 50 weight perceet of polylactlde aviug an enan ome c purity of at leas about 95 mole percent;. (3) from about 0,25 to about 8 wig t poreeoi of an aliphatic amide having from 8 to SO carbon ms; and (4) ik*m about 5 to about 20 weight percent of poly vinyl acetate. All of the aforementioned weight percentages are based on the overall weight of the hot melt adhesi e.

|03?| The first component hen of the hot melt adhesive cotnposition is a low molecular weight lactic sold oligomer or polymer, & gene al, the lactic acid oligomer or polymer has a somber average molecular weight of less thatt about 2000. M e preferably_* the lactic acid oligomer or polymer has- a numbe average molecular weight of less than about IbOO, The lactic acid oligomer or polymer generally makes up from 8 to about 50 weight percent of the hot melt adhesive composition. More re erabl , the laciic acid oligomer or polymer makes up from 15 to about 40 weight percent of the composition ,

1038 The second, componen of the hot melt adhesive composition is a poiylactide. In eestam. embo ments, the poiylactide is m L-polyketide having m L-lsomer pnrity (enantiomeric purity) of at least ab ut- 95 mole percent and more prefemMy at least about 98 mole percent H e , In other embodiments, a poiylactide having D-lsomer purity (enantiomeric pnrity) of at least about 95 mole pe cent could be used, instead.. The polyiaeiide snor h makes p from 10 to about 50 weight percent of the hot melt adhesive composition. More preferably, the poiylactide makes up from 15 to about 30 wei ght percent of the compositi on... |039| The weight a erage molecular weight, of me polytestn e is preferably irom. about. 80,000 to abooi 120,000. Ail exam le of a sui able polylactide is IHOEO 325 ID, available from Natureworks, LLC Mfe The third o>mpose»t of the hot tnelt adhesive op sition is an aliphatic amide. In general, the aliphatic anikfe s a molecule having fkm« S to 50 c r on atoms. More preferably, the aliphatic amide m fm . 18 to 40 carbon atoms_* Examples of suita e aliphatic amides loemde steamaide. beheo tmo ^'-ethyleae- ^ia- fey lroxymea amide, and n itores thereof More preferably, the aliphatic amide Is Ν,Ν^'- eihyk¾e h¾-1 ~h d.F y8teatamide. & ge&erai, the aliphatic amide makes up from 0.25 to about S weight percent of the hoi melt dh si e com osition. Mote preferably,, the aliphatic amide makes irp from (1.25 to about 2 weight percent of the e mposlti m

[Ml.} la general, the aliphatic amide preferably m a melting temperature of at least about 50 deg e s CI More r fer bly, the aliphatic amide has a mehiug temperatare of at least about 90 degre s C.

|843| The feurth eon^onem of the hot melt adhesive composition is polyvinyl acetate, lo general, die polyvinyl aectate .makes up from 5 to about 20 weight percent of the hot *nelt adhesive composition. More preferably, the polyvkyl acetate makes up ikxrn 8 to about 15 weight pereem of the composition, Xn general the poiyviuyi aectate may have a weight average molecular weight of up to about I 20_f000, Examples of such melude Vinnepaa UW1 available form Wackcx Chemfe.

|043f lit some instance, the polyvinyl aectate ma include a partially bydroIy¾¾d polyvinyl acetate, that is, a polymer which s made up of a eorobmatiou of polyvinyl acetate moieties and polyvinyl alcohol moieties, in certain. enmodmmtS_j the partially hydrohvzed polyvinyl acetate is preferabl made up of from about 60 about 90 mole percent polyvinyl acetate moieties and from about 40 to about 10 mole peroeat polyvinyl alcohol moieties. Examples of such: Include LM 10 HO available from feraray Am rica, lac. £§4 | la ce tain

the hot t k adhesive composition may also nclude a fifth eonrponem which is a terpens henolic taeksikr. In geoarai, the ierpeae phersolic taokliier prefeta !y has a glass traasilfon temperature of at least about 65 degrees G Mora preferably, the terpeae phenolic t eki rer has a glass transition temperamre of at least about 80 degrees G Examples of sui able ierpeie phenolic tac Jhers ke!ude Sylvares TP 300 nd lvares TP 2040 MM, both available fmm mm Cbemieal Com ny. Sf geaeraL the tstpene phenolic taafcifler makes up ftom 10 to about 40 weight percent of the hot melt adhesive c m siti n, More referabl , the t en© phenolic taekifier makes op §om 15 to about 35 weight percent of die com os te, 4£f Ϊ eertam embodiments* the hot melt adhesive composition may also include a sixth component which Is a etmdepsatlors copolymer formed from the eopolyrsiefkaom of dlol a¾d a diearfeoxylic acid. Examples of suitable copolymers itielodc of poiypropykiie fuatamte_s poiybirylene &mar¾fe, polyh xyl famarate, polyhoiylene s«cd»a$e_> po!yet yiersa oxalate, pD!yCl₅4-dimethylol eyelohexyl) oxalate,, md mi ures dieroo Mote preferably, the condensation copolymer is polypropylene frniaraie, pofyhutyiene sueci?xate_s or a mixture thereof. The manher average moiecaka- weight of the condensation copolymer s preferably from about 2000 to about 6000, f$4?| I» geneml, the condensat on copolymer makes up from 10 to about 40 weight percent of the hot melt adhesive composi ion More preferably, the c ndens ti n eo s !ymof makes up from 15 to about 3 weight percent of the composition, fCM SJ The cond ns tion copolymer typically has a melting point temperature of at least about 70 degrees C More preferably, the condensation copolymer has a melting temperattre of at least about 100 degrees G

P49| Optionally, the hot imk adhesive composition may also loe de one or more of the following components; (! ) polyhydrie alcohols such as glycerol, polyethylene glycol, or polypropylene glycol; (2) plastiel¾er sack as citrate, succinate, adipate, or bcn¾oate esters or cpoxidlsed vegetable oils such as soybean, castor, or c conut oils; (3) high molecular weight polyesters such as porycajarolactoae, polyglyeolic acid, or BASF BCOFLEX; ( ) water scavengers such as irim-dmiyl borate, calcium oxide (Qr0)_s or magmtsmm oxide ( gO) (5) hydrolysis stabilisers such as oarbodimides (e.g., Stabaxol I LP) o lactic acid osiers of polyvinyl alcohol or acrylic acid; {<>) ax diloeats; (?) im iosldams such as irganox 1010, 8HT_> ΒΗΛ. or alpha^ocopherol and/or (8) estertfied sta bes,

| S | Ideally, all of the oomjKsnents of the hot melt adhesive w ld he biodegradable, recyclable, and/or renewable; however, it is difficult to prepare an adhesive having suitable bonding and shelf lite characteristics us ng only these materials. Nonetheless, aecoitifeg to certain embodiments of die preaent disclosure, at least about 51 weight percent of the somponents of the hot melt adhesive are biodegradable, recyclable, and/or renewable. More preiemhiy, fern about. 60 to about 90 weight percent of the components of the hot melt adhesive are biodegradable, recyclable, and/or renewable. S 11 The components of the hot melt adhesive composition are typically combined and blended, together at a tenmerarure of about 130 to about 190 degrees C< In some emhodtmoots of the resent disclosure, it is believed that order of addition of die components when, mixing does not affect the final properties of the adhesive composition. In other emhodirnents, however, it preferabl to add the condensation copolymer to the composition las , alter first mixing the remaining components. For instance, if the condensation copolymer is highly oi satnra ed (e,g._? fxdypropylerre fomarate) then It may he advantageous to blend this component into the composition last S!J In some embodiments, the blending may he carried out using a heated tank with a suitable agitator such as a high shear miser lot example. Alternatively, h w ver, the eornponents of the hot melt adhesive comrxjshion may he added to an extruder and heated and mixed within the extruder before being extruded through a die, If desired, the hot melt adhesive composition may be exnuded directly onto a suitable sobstmux More typically, however, the hot melt adhesive composition is initially exnuded into pellets or airy other desired form and then is allowed to cool and solidify, Once in a pdietked or othe solid form, the hot melt adhesive may be packaged for storage and or slipping. The pellets are eventually re ated and melted md applied to suitable substrate dwring a second extrusion stop. f0SS| Once prepared and thoroughly blend d, the hot melt adhesive composition as been found to have a melting point of a out 145 to about 155 degrees€, More p fera ly, the hot x ti adhesive com osition m a melting point of a out 152 degrees C< f054J Advantageously, the hot melt adhesive composition has been found o provide a pot life of at least about 4 to 1.2 hours before significant eg d ti n of th« adhesive eorapositlori. renders the composition unusable, 0S51 In general, rJ¾e hot xmli adhesive has m tM visc sity from about I _>000 to about 1.0,000 eP at a temperature of about 160 deg ees C, More preferably, the hot melt adhesive h s an initial viscosity from about 3,000 to shoot 7,000 oP at a temperature of about 60 degrees€, Still mo e preferably, the hot melt adhesive preferably has art Initial viscosity from about 4300 to about 5_S500 sP t a temperature of about im degrees a fOSiiJ Once prepared, the hot melt adhesive composition is ^'heated to a temperatiire of at least about HQ degrees C (preferably from ah ist 160 to about 170 degrees C) In order to Insure good iowabillity. The hot melt adhesive composition may then be applied to y desired suhstrate sur ace. For instance, the hot melt adhesive ma be applied to aper or paperhoard. Substrates to which, the hot me.lt adhesiv is applied may be used for both hot md eold food service items (such as plates, cap, and bowls) paperhosrd packaging, and eariom or ease seals including those used for frozen foods,

| §7f Suitable methods for application of the hot melt adhesive to the substrate include extr ion no¾sde application, hand gnu application* roll coating application, aad profile mapping application.

|0S8J Onee the hot melt adhesive is applied to the substrate and allowed to cool, the adhesive preferably exhibits good initial hood strength. Surprisingly, and advantageously, the not melt adhesive of the present disclosure has been observed to retain i bond strength for an extended atnouni of time. Even after being applied to a substrate for a aut oae year, the adhesi e generally .retains saf eieut hovd strength to r main bonded to the substrate. Sf The Ixmdmg so-eogih of the adhesive was ch racte ised by a peel temperature test, The hot melt adh s e generally h s a peel test ien eraliue of fk>m about 60 to ab u 153 degrees C and snore preferably h s a peel test temperature of from aboat 72 to about 153 degrees€. fO j This peel temperature test is widely used md understood fey those of o mary skill m the art It provides a practical measure of bo»4 strength as a limetion of temperature. Such m¾as» w »½s are useful sitxce hot melts adh siv are comm nly sold and used based on the temperatures they will tolerate. For e m le, ease ami carton seal adbeslves typically seed to withstand temperatures of about 1 0 degrees F for over the road shipping purposes, hot beverage glees need to withstand temperatures O aho¾t 1 degrees F (i.e., the temperature of hot sol!ee), and ad esives for hot ill! containers (msh -juke pouohes) need to ithstund temj^tures of about 160 degrees F. f tf la d¾e peel temperature test a 1/E inch diameter bead of adhesive as applied at about l CPC using aMordsoa "Mkisqulrt ΠΓ hot melt adhesive applicator onto a section of 40 Ih/reara krafi paper. A second sheet of the same paper was quickly l ced ki allgooieot a¾d pressed thereto to form a kraft.~to-k.rait bond. Stri s approximately one inch wide were out fm the glued sample perpeadieokr to the glue hoe and were hung in a temperature- controllable oven with one end feed to a raek m the oven while and a 100 gram, weight was attached to the free end. The temperature of the oven as raised at S^C totervals every 20 tnhmries oatil bora! atam t n occurred. The temperature at which f ilure wi Observed is designated the 'Teei T m rmttt e^

[ 2 Without being hound by theory, it is believed that the condonation of a lactic acid oligomer,, an aliphatic amide, and a high ommtiomerie parity FLA term a highly crystalline mixture even after partial degradation of the materials resulting ia relatively low molecular- weights (from aboot 2,000 to about 20,000), This highly erysudlme material la believed to exhibit improved r istance to farmer degradation on the shelf It is also believed to impart high hmt telerafi.ee due to it highly orystaliiue oatum. la addition, it hm bean found, that the relatively small amount of polyvinyl acetate provides a great amount of tackiness and hood strength to the comp sit on. Tins bond stagth deri ed from the polyvinyl acetate endows for an extended period of time (op to one year or more) because the polyvinyl acetate component of the bet melt adhesive composition is generally highly resistant to degradation doe to being heated lor an emended period of time. Ibjrther, while polyvinyl acetate is a petroleiim-hased polymer, it is generally biodegradable. On the other hand, it believe thai mixtures of poly vinyl acetate and FLA, while biodegradable, have a slower rate of hydrolysis, which may aid in improving their shelf life. ff 63] In addition, the condensation polymer, by virtue of Its low viscosity, acts as a diluent, but beca se of Its high heat tolerance does not adversely lower the Fee! Temperature Teat value of t&e formulation as would other diluents such as a wax or plasticizer. The highly crystalline nature of the condensation polymer may also exert a protective affect to on degradation reactions of the lactic acid based components by forming blended structure that is resistant to penetration by ait or moisture,

II ! BXAMPIJBS

In this example, an oligomer of lactic mid and I^ ex sediol was prepared tor use hx a hot nieit adhesive. To prepare the oligomer, a 100 gallon, glass-Iked DeDletrleh reactor (fitted with an oil heater, stirrer, conden ate Hue and mcuum pump) was charge with 532 lb LTacde acid, (12 ih-mofc FUliAC; 88% solution) 31. lb 1,6» heaxanedlol (0,26 lb-mole; BASF) and 0,56 lb tin (II) octoate catalyst (Alia Aesar), The reactor w» headed to a 190 0 oil heater set point, and the stirrer was set to 50-7$ rpm. Under atmospheric p essors, when the reaction temperature reached about 111*!!, water began to boil from th reaction mixture. The water vapor was condensed md collected as a li uid,. This continued so for about 2 hours until the reaction, temperature bad reached I35°C. At this point about 87 lb of water (a 55% theoretical amount} was collected. {§$7} After this time, a vac um as applied to the reaction mixture. The pressure w s educed In a stepw se Cashless (ahottt 50 orr every 30 mm) ver a 3-4 hoar period. Durmg dbs time the reaction temperature increased to about !.67¾ md m. additional 58 lb of water was collected (92% tbeoretica!). When a vacu m of about 30 to was rescued, and die reaction ixt rre produced no more liquid water, the temperature of the oil heater as raised, to about 193T. lie reactor was heated r m additional tbree hoars {appmxim&tely 12 hours total eaction time) until the product bad: (1) a viscosity o 00- 400 cF @ I I S*C and (2) a volatile content (as determine by gravimetric loss of a sample heated to I FC for 3 rata) of CU0dUS%. At this ime, 400 lb (71% yield) of a sticky, semidiqald, amber colored material a emptied mto a SS-gallaa drum,

| 69| In this example, m oligomer of lactic acid and glycerol was prepared fo rrse iu a hot melt adhesive. To pepara the oligomer, a 100 gallon, glassdmed PeDietrleh reactor (fitted with s. oil heater, stirrer, condensate hue and vacuum pump) was charge with IS? !b L-teie acid, <2J IIMOOIC; FURAC; 88% soIutiosA 129 lb glycerol (1 .4 Ib-mok; BASF) and 0,42 lb tin 01) oetoa e catalyst (Alfa Aesar). The reactor was heated to a 1¾¾ oil eater set point, and the stirrer was set to 50-75 rpnt Under atmospheric re sure, when the reaction temperature reached about 1 i IT, water vapor began, to boil f om the reaction mixture. The water vapor was cmulet sed and collected as a liq id. This continued so tor about 2 hours until the reaction, tenmendure had reached |.35°C. At this point abou SO lb of water (58% theoretical moun ) was collected.

|07#1 After this d ne, a v&euunt was applied to the reaction, mktnre. The pressure was reduced is a stepwise fashion (about 50 tort every 30 xnin) over a three hour period. During this time die reaction temperature Increased to about 16 C and an additional 33 lb water was collected (97% theoretical). When a vacuum of about 30 torr was reached, and the reaction mixture produced no more liquid water, the temperature of the oil heater s raised to about I 3*C. The reactor was heated for an additional three hours (approximately nine honrs total reaction, dme) until the product had: (!) a viscosity of 250-300 cF { C and (2) a volatile content (as determine by gravimetric loss of a sample h ated o !80^»€ tor 3 ffik) of 0 ,10-0,30%, At this tirne, 339 lb (79% yield) of a viscous amber colored liquid was emptied mi® a 55-gaiion dr m.

|071 ] Illpiple 1 J JS lp jglfe

{ 12 h this exam le, as oligomer of lactic acid, sebaeic acid, i,3-pr«pa¾sdiol and t imetirylol ro ose was prepared for use I» a hot melt adhesive. To repa e the oligomer a 100 gallon, gl S-lined QeDiemch reactor (fitted with an oil heater., stirrer, condensate Ims and vaemnu pump) was charge with. 462 lb L aette acid. (4,5 lb-mote; POEAC; 88% Mmn) 57,8 lb sehaeie acid (0.29 lb-mole) 1.3.7 lb I ^propanediol (0.21 lb-mole; DuPont Tate a&d Lyle) 5.4 lb trimet yiol propane (0,04 lb-mole; Pemiorp) nd 0,54 lb tin (0) oeioate catalyst (Alia Aesar). The reactor was heated to a 1 0°C oil heater set oint, and the stirrer was set. to 50-75 rpm. Ondcr atm sp e c pressure, when the metios tereperature reached abou 121*C, water vapor began to boil i oro the reaches mature. The water vapor was condensed aod collected as a liquid. This continued so for about 2 hours until the reaction temperature had reached 13S°C, At this oi t about 63 lb of w er (45% theoretical amoast) was collected.

| 73| After this time, a vacwam was ap lied to the reaction mixture. The pressure was reduced in a stepwise fashion (about 50 torr every 30 roio) over a tour hour period. During this time the reaction temperature increased to about 16T and an. additional 67 lb water was collected (93% theoretical). When a vaeut m of about 20 torr was reached, and the reaction. mixt re produced so more liquid water, the temperature of the oil heater ^•was raised to about 193X-, The reactor was heated lor an additional seven hours (approximately 14 hoars total readies, time) ma l the product had: (I) a viscosity of §50- 1_*000 cP @ 127*0 aud (2) a volatile costeox (as determine by gravimetric loss of a sample heated to ISO^C lor 3 mi ) of 0.05-0.20%. At this time, 400 lb (74% yield) of a viscous amber colored liquid was emptied into a 55-gslIoa dram,

[0-75J In this eaauiple, a condensation copolymer, poly propy1eoe fbmarate) was prepared lor use in a hot melt adhesive, Mypmpyfcne i uaimte as prepared by a polyeondesation in whkh the reactants ae gradually raised to the teastton sm sra ts to avoid stri pin the 1 ,3~ptop&dio! from the r«e$io» mxtures before it hs had the opportunity to jmaci

\i ] A 100 gallon, gJarfsed DeDietrieh $ mx (fitted ith oil heater, stirrer, cc deaita Vxm d vacuum, pimp) was charge with 292 lb fematk acid, (2.5 Ib^ ol Bariek) 20! lb l,3-^nvpanediol (2,6 I mo! ~ S% molar xc ss Susterra, DoPont Tate & Lyie) and 0,49 lb tin (II) octoate catalyst (Alia Aw). ¾ reactor was heat d to WC ml heater so p in, and the stirrer was mi to 50-75 jm tinder amsospherb pt mx whoa the reaction em erate^ edied about 11 g°C₉ ae began to distil! torn the reaetor md eoitt ued to d so for about 2 h us until the reaction ternperature had reached 1.21 C and 1 lb water had. been removed. At this point, the oil boater set point s increased to !6¾*C and additional 13 lb water was emo d as the reaction lernperature increased to about 1.2^'i°C. At this point the oil heater set okt was increased to and 29 lb water was eoi!eeted as the reaction temperature Increased to about

135 > At this point the oil heater set point was increased to U C and 13 lb water was removed, as the reaction temperature increased to about 1 2*C. (total water removed u to this point was about 75% of th theoredoa! arnownt) 071 After this time, a vacuum was applied to the reaction mixture. The pressure was reduced in a stepwise fashion, (about 50 torr every 30 mm) ver a 2 hour period. During this time the reaction ten¾mature increased to about 1<*0°C and an additional 13 lb water (1 0% theoretical) was eoliectad. When a vaontra of about 30 tor was reached, the reaction was heated for an additional thee hours (a rmim e!y 12 hours tot l reaction time) until the product had: (!) a viscosity of 1,0004,500 eP @ 14 *0 and (2) & crystalline molting point of I37°C. The final yield (81%) was 400 !fe poiy(propyl.ene fnmarate),

|0?8| At this time, the vacuum was released and 23.4 lb of stearasride was slowly added to the reaetor with stirring. After 20 mimrtes, the reaetor contents were emptied, into a 55 gallon d um and were pastlllated on a Sartvik Rotofbrm Pastiilator, l¾ree hot melt adhesive ibrmel tiooii -were ttea prepared skg the ma er als described ¼ Ex¾m !$ 1 - 4. The eomposttioas of the t¾ree hot melt ad esi e fotmu ioas are sirmmari¾ed below m Table A.

[iS! J live ad¾e¾ivos of Exam les 5 - ? were raamu¾¾ra¾d ¾ing ¾ B«$ek 43 mm twin screw extruder. The temperature profile of the extruder $hmm in Table B, Polv l&ctie add), poiyCvmyi. acetate), polyCpropylene turaaraie) (Examples 5 and ?}_s the appropriate te me teidk taekrf!er, Irgasox 101.0 and Parkia 285 were dr Mended ¾«g a rotating dmm mixer and mixte was fed into Zom 1 of the extruder. The appropriate lactic aeid oligomers w metered in at Zone S a§ a liquid (.120-1 0*0 using a Nordsmx BM SO dmm mete. The extruder was operated at a rate of about SO !b/hou . Extruded ad.hesive was then pastiUated or pdktked. $2I Table A. Composition of Hot Meit Ad½s rv«s

083] Table B, Extruder .Zone ¾mp«rature Profile

|05] In. this exam , an oligomer of lactic acid ami poI (vkyl alcohol) was re ared for use is a hot melt adhesive. To prepare the oligomer_* a two liter ear-shaped flask was c ged with 1,400 grams ofm 88 weight ecent solution of L ( Iaot½ acid (PORACf 70 grama ofpolyfvbx i alcohol) (Elvanol 75- 5; DuFout) and 1, 5 grms of tin (II) oetoale catalyst (Alia Ae«)< The flask, was placed on a rotating evaporator aad heated to a temperature of about 14S*€ at 50-75 ram and atmospheric pressure. At a temperatore of a out I 2C, te began to distll from me reaction flask and was collected in the receiving flask of the rotating evaporator.

Ate perlo of about 2 hours, about 273 ml of wafe had been eolieeted m the reeeivmg flask, corres onding to about 65% of the total thoretical am uui At this ime, a vacuum was applied to the reaction mixture. The presaore was educed m a stepwise fshion (a reduction of about 1 0 Torr every 30 minutes) over a 3 hour period and the temperaiaxe was slowly raised to about !8<F€ . When a pressure of about 50-75 Torr was readied, aad the reaction mktrnre produced no mote water, the reaction as stopped md the contents of the ¾sk ere pemred oat yielding a vsco«s ora^ge-ra liquid, SHJ Three additioital hot melt adhesi e f rmula ons were then prepared sing the material described

Example § aador the maeials r viously described m Example I 4. The com os ion of die two hot melt adhesive ibmmlatiorig are summarsd below k Table CI

[089Ϊ Ta e C. Composition ofHot Melt Adhesiv ^

ίεψ χ 1 10 0.9 1. 1

ftlf lf Aside from the composi i nal dlife&ees, the ot melt adhesive eomp s m were r a d aad extruded in the same maim r as die hot melt hesive of Example 5» 7< f0#lj The to melt composition of E ample 9 was observed to retain its tackiness at ®mme to emiufss (»20*C), Thus, this composition is sstttabte or use in sealing carious of food or otte pedshahle materials which are stored in freezers or reiige?ators, f l] E am les 7, 10 and 11 illustrate hot melt adhesives wherein the terpeoe phenolic taefci kr has been omitted according to one embodiment of the present disclosure. Eliniinatioo of the taekl le may be advan ageous in som& eircinnstanees ins leads to an Increase in the overall percentage of renewable com on nts in the adhesive composition, Irs some instances, omission of the tnekifjer may lead an adhesive composition which Is com l e y c mpu able. Nonetheless, the hot melt adhesrves of Examples ?, 0 and 1 1 still eahlbit good initial vfacQsity and high peel test temperatures, 0931 T¾e foregoing description of preferred embod ments f r this Invention has been presented for purposes of illustration and description... ft Is not intended to be exhansdve or to limit die invention to the precise form disclosed. Obvious modifications or variation are possible in light of the above teachings, 'Ik erobodiraents are chosen and described in an effort to provide the best iiostraiions of die principles of the Invention and its practical application, and to thereby enable one of ordinary skill In d e art to utilise the o endon in various embodiments and with various modifications as are suited to the particular use contemplated. All such modification and variations are within the scope of the invention as determined by the appended claims when, interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

Claim L A hot melt adhesi e ecm^ mm :

f m about E to about 50 eigh petemt of a lactic acid oligomer or polymer havjn & uuraber a erag molecular weight o less that) about 2000;

from, about 10 to about 50 weight percent of poiy!aeride havkg m tio mc purity of at least about 95 mole percent;

from about 0,25 to about $ weight percent of an allplnme amide having from § to 50 carbon atoms; mi

from about $ to about 20 weight percent of polyvinyl acetate

wherein all weight percenta es are based on the overall weight o f the feat melt adhesive.

Claim 2> l¾e hot melt adhesive of Claim 1 , wherein the aliphatic amide is selected from the up eooals h g of stearamlde, bebenanrlde, N -~et ylerie»bis»i.2" Irydroxystearasnkki aud mixtures thereof

C 3. The bot mob adhesive o Claim 1, wherein the poiy!aetide has an L» enantiomeric purity o.f¾t least about 95 mole percent

Claim 4, The hot melt adhesive of Claim I, further comprising bom about 10 to about 40 weight percent of a eood o Uou copolymer formed from the copo!ymerlmtlon of a d!oi d a dicarhoxylk mid>

Claim 5, The but melt adhesi ve of Claim 4_;! wherein the condensation copolymer is selected from the roup eomlstfog of polypropylene fumar&te, polybutyleoe mmarate, poiyhexjleoe faunar te, polybutylene succinate^ polyethyle»e oxalate, poiy(L4- dh ethyksl cyciohex l) oxalate, and. mixtures thereof

Claim 6, The hot melt dhesiv of Claim I, wherein the hot melt adhesive has m ksM viscosity from, about 1 ,000 to about 10,000 cF at a temperature, of abou ! 60 degrees C,

Claim 7, The to melt adhesive of Claim 1, wherein the aliphatic amide has a melting temperature of at least about $0 degrees C

CMm S, lite hot melt adhesive of Claim 1 _> further comprising from, about 10 to about 40 weight percent of tetpene phenolic tacklfler having a glass transition temperature of at least about 5 degrees C Claim 9, The hot mel adhesive of Claim 1 , wherein at least about 51 weight ercent of the components of the dot melt adhesive are biodegradable, recyclable, ami or renewable.

Claim 10, The hot melt adhesi ve of Claim 1 , wherein the hot melt adhesive, when applied to a substrate, has a peel test tetrrperature of from about 6 to about 153 degrees C and mtohis sufficient boad strength to remain bonded to the su s r te for at least one year.

Claim 1 1, Asa a^es-l e^eosted substrate comprising:

a substrate having at least a fet side; ami

a hot melt adhesive coating applied to at least of portion of the substrate first side, wherein, the hot melt dhesive coaling c m ris s

fto.m about $ to shorn 50 weight percent of a lactic acid, oligomer or polymer having a tmmber a verage molecular weight of less than about 2000,

prom, about 1.0 to about 50 weight percept of polylactide having ap enantiomeric polity of at least about 95 mole percent,

from about 0.25 to about I weight percent of an aliphatic amide having f m S to 50 carbon atoms, and

from about 5 to about 20 weight percent of polyvinyl acetate wherein all weight ercen ges are based op the ov erall weight of the hot melt adhesive.

Claim 12. The adhesive-coated substrate of Claim. I L wherein the aliphatic amide is selected from the group consi irtg of stesraniide, ebepamide, N^^e h leue- bis~i2«hydroxys earamide, and m!sTares thereof.

Claim 13. The adhesive-coated su st e of Claim. 1.1 , wherein the polylactide has a¾ L-enaph.omerk purity of at least about 95 mole percent.

Claim 14, The adhesive-coated substrate of Claim 1 C further comprising from, about 10 to about 40 weight peroetit of a oopdepsation copolymer formed from the copo!yrner!^ation of a dioi and a dicarboxylie acid.

Claim 15, The adhesive-coated substrate of Claim 1 , wherein the condensation copolymer is selected from the group eonsistipg of polypropylene fhmarate, po!yhotylene fitmrat®., polyhexylene !nmaraie, potybutykae suc^iaats, polyethylene ox late, poly (1,4- d.hnethylol eydote l) alat , d mixtures thereof

Claim 16> The adheslve^oated substra of Claim 1.1 , wherein the hot melt adhesive has an initial viscosit from about I„000 to about 10_*000 eF at a temperature of about 1 0 degrees C

Claim. I The adheslve-eoated substrate of Claim 1 L wherein t e aliphatic amide to a melting temperature of at least about 50 degmea.

€ m 18. The adheslve-ooated substrate of Claim. 1L Iktner eornprismg from about 10 to about 40 w ght pe cen of a terpene phonolk tackliier having a glass transition temperature of at least about 65 degrees C,

Claim 19 < The adbeai%¾~eoated substrate of Claim 1 L teremi!ie substrate com rises pape or paperk>ard.

Claim.20. The adheslve-eoated substrate of Claim 1 1 , wfeereln at least ab ut S! weight percent of the eon oneuts of the hot melt adhesive am biodegradable, recyclable, and/or renewable.

Claim 2L The sdbes!ve»eoatecl substrate of Claim 1 1, wberelo the hot melt adhesive has a pee! test temperatus? of irom about 60 to about 1.53 d grees€ and retains suMoseot bond strength, to remain bonded to the substrate for at least one year.

Claim 22. A method for applying a hot melt adhesive to a s bstrat , comprising the steps of:

providing a hot melt adhesive eotupdsing

from about I to about SO weight: percent of a lactic acid oligomer o? polymer haviug a number average molecular weight of less than about 2000₉

firors about 10 to about 50 weight percent of polylaetide havmg enantiomeric purity of at least about 95 mole p rcent,

from about 0.25 to about 8 weight percent of an aliphatic amide having from. 8 to 50 car!xui atoms, and

from about S to about 20 weight percent of polyvinyl acetate wherein all weight percentages are based on the o verall weight of the hot melt adhesive; nd subsequently applying the hot melt adhesi ve to at l east a portion of at least one s de of a s ubstrate.

Claim 23. The method of CMm, 22, wherein the altphatk amide is selected from the group consisting of steamniide, beheiramide, .N'-oih len -hk-l 2- hydroxysteammlde, and mixtures thereof

Claim 24, The method of Claim 22, wherein the polylaot e has m L- enantiomeric purity of at least about 95 mole rcen

Claim 25, The method of Claim 22 wherein die ho melt adhesive further c m ises from about 10 to about 40 weight percent of a c ndensati n copolymer .f rmed from the eopoiy mediation o diol and a dlcarboxylie acid.

Cham 26, The method of Claim.25, herem die eondensntlon copolymer is selecte from the group consisting of polypropylene himar&te. pokhutykne mmarate, polyhexylene mmarate, p lyb tykne succinate, polyethylene oxalate, po!y(C4- dimethylol c eiohexyl) oxalate, nd mixtures thereof

Claim 27 < The method of Claim 22, wherein the hot melt adhesive has an initial visco i y from about 1,(100 to about 10,000 el*

Claim 8. The method of Claim 22, wherein the a!lphat amide has a melting temperature of at least about 50 degrees C.

Claim. 29, The method, of Claim 22, wherein the hot mdt adhesive further comprises firom about 10 to about 40 weight percent of a terpeoe phenolic tackiller oviog a glass transition temperature of at least about 65 degrees C,

Claim. 30.. The method of Claim 22, wherein the s bstr t comprises paper or paperhoard.

Claim 31. The method of Claim 22, wherein at leas about 51 weight percent of the components of the hot melt adhesive are biodegradable, ree elahle, and or renewable.

Claim 32, The method of Claim 22, wherein the hot melt adhesive has a peel test temperature of from about 60 to about 153 degrees C and reiiins sufficient bond strength to remain bonded to the substrate tor at least one year.