PVB Sheet Recycling and Degradation

5 PVB Shee Recycling and Deg ada ion Michael Tupý1, Dagma Měřínská1,2 and Vě a Kašpá ko á2,3 1Depa men o Polyme Enginee ing, Facul y o Technology, Tomas Ba a Uni e si y in Zlin, Zlin, 2Cen e o Polyme Sys ems, Uni e si y Ins i u e, Tomas Ba a Uni e si y in Zlin, Zlin, 3Depa men o Fa , Su ac an and Cosme ics Technology, Facul y o Technology, Tomas Ba a Uni e si y in Zlin, Zlin, Czech Republic 1. In oduc ion Inc easing g ow h o aw ma e ial p ices, en i onmen al aspec s and s ill g owing land ill ees b ing abou he inc easing in e es encoun e ed wi h he plas ics was e ecycling. Globally, he p oblem has been sol ed o he common plas ics such as polyole ins, poly(e hylene e eph ala e) and poly(s y ene). Though ex ensi ely used o he glass lamina ion, poly( inyl bu y al) (PVB) does no belong o his g oup. I is gene ally known ha du ing he glass lamina ion p ocess, la ge olume o PVB im is o med. The PVB polyme is mos ly used in he o m o plas icized PVB shee o p epa a ion o lamina ed sa e y glass (LSG). A p esen ime, Solu ia, DuPon , Seki sui and Ku a ay a e wo ldwide PVB manu ac u e s. The PVB is he ma e ial which can s ick oge he loa glasses wi h holding excellen op ical and mechanical p ope ies o he glass lamina e (I ano , 2006; . Elas ici y, mechanical s eng h, oughness, high ligh ansmission and he adhesion o glass a e he mos signi ican PVB p ope ies (Tupý, Měřínská, e al, 2010). Toughness o PVB shee is based on high molecula weigh o PVB chain. Ce ainly, he PVB has o be plas icized o achie ing high ma e ial elas ici y (Iwasaki, e al, 2006; Kelle , Mo elmans, 1999; S oboda, Balazs., e al, 1988). Admi edly, he plas icize mus no educe ligh ansmi ance h ough he shee , PVB adhesion o glass, gene a e haze and yellowness, and mig a e ou o he polyme ma ix (Wade, D'E ico, e al, 2004). In addi ion, plas icize mus ha e pe ec compa ibili y wi h he polyme and low e apo abili y du ing p ocessing condi ions. 2. Sou ces o ecycling o PVB shee Wo ldwide, 65% o all PVB shee s a e used in au omo i e applica ions (Dhaliwal, Hay, 2002). Acco ding o da a om (OCIA, 2007), he wo ldwide ca ’s p oduc ion is es ima ed a ound 60 millions ca s pe a yea . Assuming ha one windshield con ains app ox. 1 kg o PVB shee , o al amoun gi es be ween 60-70 million kg o PVB shee s pe yea . In addi ion, by-p oduc s om PVB shee s manu ac u ing (5%) and immings (< 10%) om windshield p oduc ion mus be added (Go ogho ski, Escapan e-Ga cia, e al, 2005). I ep esen s o al amoun o 80 million kg o au omo i e PVB shee was e annually. To al wo ldwide amoun o p oduced PVB shee s o au omo i e and a chi ec u al indus y is es ima ed a ound 120 million kg pe yea . www.in echopen.com Ma e ial Recycling – T ends and Pe spec i es 134 2.1 By-p oduc om shee manu ac u ing p ocess This kind o PVB shee has he bes quali y o ollowing ecycling p ocess. By-p oduc shee s a e no con amina ed by powde agmen s bu he e may be p esen some un- homogeneous pa s like plas icize , ligh and hea s abilize s, adhesion modi ie s, pigmen s and o he elemen s o he sys em. The easons why he shee has o be e-p ocessed a e some speci ied de ec s in manu ac u ing echnology ( hickness, shee oughness, edges). In e e y case, shee edges mus be cu app ox. 10-20 cm om he edge beginning. The PVB shee wi h a wid h a ound 2-3 me e s has e y high ma e ial sh inkage in his place. The edges can be eplaced back o he ex usion p ocess o e-ex uding (Z oníček, 1999). 2.2 T im The i s s ep in LSG manu ac u ing is he lamina ion o PVB shee be ween wo glasses. I his pa , p obable de ec s on lamina e edges mus be educed. I is pe o med by laye ing o PVB shee be ween glasses wi h a la ge shee su ace han he glass sizes a e. P epa ed “sandwich” is ixed by nipp- oll p e-lamina ion p ocess and consequen ly i is possible o im o o e sized PVB shee . While he shee o e size would no be used, he lamina e would be p oduced wi h isible de ec s (i does no mee he quali y speci ica ions) (S oboda, Balazs., e al, 1988; Z oníček, 1999). The quan i y o a im gene a ion depends on he geome y o p oduced windshield and he geome y o used PVB shee su ace. The wid h o im ob ained om he p e-lamina ing p ocess is a ound 1–20 cm, based on glass geome y. The e o e, he im quan i y is be ween 5-10% om o al amoun o p ocessed PVB shee and he wo ldwide PVB im capaci y ob ained om he windshield lamina ing p ocess is app ox. 4-6 million kg (S oboda, Balazs., e al, 1988; Z oníček, 1999). The im is c ea ed also a manu ac u ing o a chi ec u al LSG. Ne e heless, he a io o a collec ed a chi ec u al im is lowe han amoun o au omo i e im. I is in luenced by a highe glass powde con amina ion o his im (di e en imming echnology) (Z oníček, 1999). 2.3 PVB shee om windshield Some specialized companies deal wi h he e-applica ion possibili y o PVB shee ob ained om ecycled windshield. All p esen ecycling p ocesses p oduce a good quali y o glass sc ap which is ully e-used in he glass ba ch. Howe e , he sepa a ed PVB was e is no ecyclable due o high amoun o glass, wa e con en in he shee , pa s o colo PVB shee s, mixed o a ious PVBs (a e blending a haze is c ea ed) and o eign plas ic ma e s (Z oníček, 1999; Plaček, 2006; Recycling .., 2007; Tupý, Měřínská, 2011). Ne e heless, i somebody would de elop he ecycling echnology ensu es high-g ade o glass sepa a ion, ob ained PVB shee may be e-p ocessable o new PVB shee wi hou op ical de ec s (Tupý, Měřínská, 2011). Mo eo e , i is necessa y o emain ha he lamina ed (in e glassed) PVB is no essen ially exposed o UV adia ion (up o 320 nm), mechanical s ess, ele a ed empe a u e, oxygen and any a ious subs ances. Thus, he in e glassed PVB shee s should keep e y simila www.in echopen.com PVB Shee Recycling and Deg ada ion 135 physical p ope ies as ex uded ma e ial be o e he lamina ion p ocess and i can be e- ex uded and e-lamina ed o new PVB shee again. 3. PVB shee composi ion 3.1 Poly( inyl bu y al) The way assigned o PVB p oduc ion is no easy. Fi s ly, i is necessa y o p oduce poly( inyl ace a e) (PVAc) by he adical inyl ace a e polyme iza ion. Consecu i e hyd olysis a acidic o basic ambien c ea es poly( inyl alcohol) (PVAl) which p o ides poly( inyl bu y al) by ace aliza ion wi h bu y aldehyde a acidic en i onmen . The inal s uc u e o high-molecula PVB is used o LSG manu ac u ing and i is compounded om a ac ic copolyme s 80% o inyl bu y al, 18-23% o inyl alcohol and up o 1% o inyl ace a e [Wade, D'E ico, e al, 2004; Dhaliwal, Hay, 2002; D'E ico, Jemmo , e al, 1996; Nghuen, Be g, 2004; S oboda, e al., 1970). This chemical s uc u e, iewed in Fig.1, is he same o e e y manu ac u e oday. Ne e heless, exac consequence and p ope ies o e e y PVB shee depends on e e y PVB ype, manu ac u e and PVB shee composi ion. The shee is mos ly s abilized by an ioxidan s and he mal s abilize s in many imes (Sa lex, 1993). Fig. 1. PVB chain s uc u e wi h composi ion o unc ional g oups: inyl bu y al 81%, inyl alcohol 18-23%; inyl ace a e <1%. Final PVB p ope ies a e assigned by polyme iza ion deg ee o inpu PVAc, dis ibu ion cu e o molecula weigh , PVAl hyd olysis deg ee, ca alys acid s eng h, eac ion empe a u e and PVAl con e sion deg ee o PVB. The las one is c ucial o inal pola i y o p oduced PVB. The PVB polyme is whi e powde , dissol able in e hanol, THF, ke ones and o he semi-pola dissol en (M k ičko á, Daňhelka, 1984). The PVB solubili y depends on – OH g oup con en in he polyme chain and PVB molecula weigh (Physical p op.SekiSui, 2001). 3.2 PVB shee Ce ainly, achie emen o high PVB oughness mus be p o ed by polyme plas icizing. Howe e , he plas icize mus no conside ably educe ligh ansmi ance h ough he shee , inc ease haze and yellowness, educe PVB adhesion o glass and mig a e ou o he polyme ma ix (S oboda, Balazs, e al, 1988; Z oníček, 1999). The plas icize also mus ha e pe ec compa ibili y wi h polyme ma ix and i s e apo abili y du ing he p ocessing is p ohibi ed (Z oníček, 1999). Di e en plas icize s, used in beyond, we e o example ie hylenglycol-di-2-e hylbu y a e, dibu hylsebaca e, e ae hylenglycol-di-hep anoa e and www.in echopen.com Ma e ial Recycling – T ends and Pe spec i es 136 dihexyladipa e (Dhaliwal, Hay, 2001; Z oníček, 1999). Men ioned plas icize s ha e di e en molecula pola i y. The e h ough, due o his i was indispensable o p oduce PVBs wi h di e en amoun o hyd oxyl g oups in PVB chain (Dhaliwal, Hay, 2001; D'E ico, Jemmo , e al, 1996; Phillips, 2005). The inal polyme sys em has a di e en abso babili y o he plas icize and wa e (M k ičko á, Daňhelka, 1984). A p esen ime, p oduced PVB shee s assigned o he glass lamina ion a e plas icized wi h 28% o applied plas icize ; mos ly ie hylenglycole-bis(2-e hylhexanoe e), (labeled 3GO) (Wade, D’E icco, 2004; Phillips, 2005; Mis e , Bianchi, e al, 2007; Smi h, Ryme , e al, 2008). Due o men ioned shee physical p ope ies, he mos impo an cha ac e is ics o windshield a e high mechanical s eng h and abso babili y o kine ic ene gy du ing ca - c ash (Kelle , Mo elmans, 1999; S oboda, Balazs, 1988). Howe e , PVB in e laye mus keep glass pa icles on i s su ace [2, 3]. All hese desc ibed p ope ies p o ide an exac ly adjus ed adhesion g ade o PVB o glass. Because he PVB has exceedingly high adhesion deg ee i canno be used o au omo i e glass lamina ion. Thus, high adhesion deg ee i is necessa y o educe o ½ o he o iginal adhesion alue (Kelle , Mo elmans, 1999; Wade, D’E icco, 2004; Dhaliwal, Hay, 2004; Smi h, Ryme , e al, 2008). The i gin adhesion is educed by an addi ion o o ganic sal s o alkali me als o alkaline-ea h me als du ing an ex usion p ocess o plas icized PVB shee . This is desc ibed in se e al pa en s (Smi h, Ryme , e al, 2008; Aoshima, Shohi, 2000; D'E ico, 1995; D'E oco., 1997; Fowkes, 1987 He man, Fabian, e al, 1984; Shichi i, Miyai, e al, 2002). The mos ly used subs ances modi ying he adhesion a e o ganic sal s o Na+, K+ and Mg2+. Ion a io and i s o al amoun a e s ic ly speci ied (Smi h, Ryme , e al, 2008; Aoshima, Shohi, 2000; D'E ico, 1995; D'E ico., 1997; Fowkes, 1987 He man, Fabian, e al, 1984; Shichi i, Miyai, e al, 2002). Mo eo e , he wa e con en in PVB shee mus be in ange 0.3-0.5% which is necessa y o a main aining he equi ed adhesion g ade (Kelle , Mo elmans, 1999; Wade, D’E ico, 2004; D’E ico, Jemmo , 1995; Shichi i, Miyai, 2002). 4. Ex usion o PVB shee The o ma ion o he PVB im is he consequence o he p oduc ion echnology, in which lamina ed glass wi hou de ec s ha ing i egula shape a e manu ac u ed. The PVB assigned o e-p ocessing is usually ecycled oge he wi h he was e shee s o igina ing om he PVB manu ac u ing (Tupý, Z oníček, e al, 2008). Howe e , o ind he ideal PVB e-p ocessing condi ions is no easy. Due o i s composi ion, PVB is e y sensi i e o he deg ada ion and he mig a ion o plas icize . I was ound, ha a he a mosphe ic p essu e, plas icize mig a es a he empe a u e o 260 °C (Dhaliwal, Hay, 2002). Du ing epea ed p ocessing o plas icized PVB, bo h wa e and plas icize we e epo ed o be ex ac ed om polyme by acuum. Howe e , he loss o plas icize a he common p ocessing empe a u es (up o 200 °C) is minimal (S oboda, Balazs, 1998). Based on se e al au ho s (Kele , Mo elmans, 1999, S oboda, Balazs, 1998; Nagai, 2001; Nehe , 1936; S oboda, 1987), all PVB shee manu ac u ing echnologies a e based on simila p inciple. Mel plas icized PVB is ex uded by shee ex usion die a empe a u e 160-220°C in o wa e . The sc ew placemen is e acua ed in o de o adjus he wa e con en in he www.in echopen.com PVB Shee Recycling and Deg ada ion 137 shee . The PVB mel e ains i s shape, hickness and speci ic shee su ace which a e necessa y o de-ae a ion a p e-lamina ion p ocess (S oboda, Balazs, 1998; Z oníček, 1999). Plas icize and addi i es addi ion uns a mixing equipmen s be o e he ex ude in many imes. The PVB shee is mos ly manu ac u ed a he hickness 0.38 mm (LSG o a chi ec onical indus y) and 0.76 mm (LSG o au omo i e and a chi ec onical use). Special applica ions equi e hicknesses 1.14 and 1.52 mm. The wid h o PVB shee can be up o 3.5 me e s. Manu ac u ed PVB shee is olled and ei he sepa a ed by hin pa e ned polye hylene shee o olled unde -cooled (Tg = 15°C) because he PVB shee mus no be s uck o ollowing use (S oboda, Balazs, 1998; Z oníček, 1999; Sa lex, 1973). Shea and he mo oxida i e deg ada ion o polyme ep esen s mo e se ious p oblem obse ed du ing ep ocessing. Bo h deg ada ion ypes induce he clea age o polyme chains, albei he deg ada ion mechanism is no he same. Gene ally, he sho ening o polyme chains nega i ely in luences mechanical p ope ies o PVB, esul ing in an undesi able lowe ing o sa e y cha ac e is ics o he p oduced shee . The de e io a ion o mechanical p ope ies o PVB consequen ly dec eases i s abili y o abso b he mechanical ene gy (when i is used o he sa e y ca glass) in he case o an acciden (Tupý, Z oníček, 2008; Tupý, Měřínská, 2010). On he o he hand, a dec easing o molecula weigh and a dec easing o iscosi y caused by he deg ada ion can a o ably in luence heological p ope ies o PVB mel du ing he ex usion on he la die (Měřínská, Tupý, 2010; G ache , Klimenko, e al, 1974). In o de o dec ease powe consump ion du ing e-p ocessing, PVB hyg oscopici y can be u ilized. Because wa e con ained in PVB ma ix can ac as an addi ional plas icize and lowe he igidi y o he ma e ial, p ocessing o “we ” PVB can be ad an ageous (M k ičko á, Daňhelka, 1984). Howe e , du ing he e-p ocessing o ma e ial con aining high mois u e con en (8 %), wa e can eac wi h bu y ic g oups, which induces he change o he polyme s uc u e. As he consequence, hyd olysis occu s signi ican ly changing he inal p ope ies o he e-p ocessed PVB (Dhaliwal, Hay, 2002; Měřínská, Tupý, 2010). The aim o he ollowing es was o de e mine he deg ada ion o PVB shee a di e en kneading condi ions and o es ima e an in luence o empe a u e, ai oxygen con en and mechanical s ess on he cou se o deg ada ion p ocess. The wo k is also ocused on he possibili y o ind op imal e-p ocessing condi ions o PVB whe ea he mechanical and he mal deg ada ion as well as yellowness o he e-p ocessed polyme a e minimal. 5. PVB shee deg ada ion by he mog a ime ic analysis Fi s o all, he ela i e he mal s abili y o comme cial PVB sample was measu ed by he mog a ime ic analysis, om mass loss agains empe a u e plo s. As he Fig.2 shows, weigh loss occu ed in wo dis inc egions be ween 175–325 and 325–500 °C and co esponding o abou 27-28 and 65-70% mass loss. No ma ked di e ences we e obse ed be ween he a ious comme cial g ades. The i s pa o empe a u e ange is he plas icize e apo a ion. The inal weigh loss was he same o all he samples and a b own esidue, app oxima ely 5% o he o iginal mass (Tupý, Měřínská, 2011). The e ol ed ola iles we e analyzed by mass spec ome e as a unc ion o ime and empe a u e a ixed m/z a ios. www.in echopen.com Ma e ial Recycling – T ends and Pe spec i es 138 These co esponded o he op m/e a io o ace ic acid, bu enal, bu y aldehyde, benzene and oluene he expec ed p oduc s om he he mal decomposi ion o PVB (Wade, D’E ico, 2004). Fig. 2. TGA e alua ion o plas icized Bu aci e PVB shee . Li le o no deg ada ion p oduc s we e obse ed below 250 °C al hough he PVB samples had los abou 10–12% o mass unde hese expe imen al condi ions we e ini ially. The majo p oduc s o he decomposi ion we e obse ed abo e 260 °C. Ace ic acid was a mino componen o he ola ile deg ada ion p oduc s. A oma ic species, such as benzene and oluene, we e also obse ed. These ha e been a ibu ed o he b eak down o he polyene p oduc s p oduced by he elimina ion eac ions. F om he ela i e % mass loss and he absence o ola iles de ec ed by he mass spec ome e i was deduced ha he PVB was p ima ily losing plas icize in he empe a u e ola iliza ion p ocess be ween 200 and 260 °C. The loss o addi i es om a polyme is a complex p ocess in ol ing di usion, anspo and e apo a ion om he su ace o he polyme . 6. Deg ada ion by kneading 6.1 Samples p epa a ion By he eason o inding deg ada ion mechanism o plas icized PVB, his ma e ial was ep ocessed by kneading, olling and p essing. Bo h d y (0.5 % wa e ) and we (8% wa e ) shee s we e es ed. Inc easing mois u e con en was eached by he soaking o “d y” PVB shee in wa e o 14 days (G ache , Klimenko, 1974). Samples s essed by kneading we e p epa ed in he B abende kneade wi h wo blunde s W50 a he ic ion o 2:3. Volume o he hea ed chambe was o 55 cm3. Cons an amoun o www.in echopen.com PVB Shee Recycling and Deg ada ion 139 40 g PVB was placed in he chambe and p ocessed o 10 minu es a di e en empe a u es (100, 130, 160, 190, 220 °C) and o a ion speeds (40, 60, 80 pm). The chambe o kneade was illed only o he ¾ o he olume in o de o ha e he su icien amoun o oxygen in o de o s udy he mo-oxida i e deg ada ion. Du ing kneading, bo h he mo-oxida i e and shea deg ada ion a e assumed o ake place. In o de o simula e solely shea deg ada ion wi h absence o he mal s ess, PVB shee s we e e-p ocessed by olling a he empe a u e o 78°C in he p esence o ai . Labo a o y double- olle was used. Rolle s we e p ehea ed o 60-70°C in o de o allow he PVB calenda ing co esponding o p ocessing o he ubbe . A e he ini ial p ehea ing, he olle empe a u e was kep only by he ene gy dissipa ion. A e 10 minu es he empe a u e eached 78°C and his alue emained almos unchanged. Pu e he mal deg ada ion wi h low shea s ess was simula ed by p essing. PVB was placed be ween wo PET shee s p e en ing he con ac wi h ai and hus oxida i e deg ada ion. Then, he ma e ial was p essed a 1 MPa a empe a u e o 160, 190 a 220°C o 10 minu es. D y PVB was es ed a all he abo e p esen ed condi ions; we one was es ed a all empe a u es bu only wi h 60 pm. 6.2 Analysis and me hods Mechanical p ope ies o he s essed samples we e de e mined using a T 2000 Tensile es e (Alpha Technologies) wi h he displacemen a e o 500 mm/min a oom empe a u e. Fo es ing, ma e ial was p essed on o he pla es wi h he hickness o 1.0 mm a he empe a u e o 130°C and he s anda d es ing specimens we e p epa ed. Tensile s eng hs and s ain we e de e mined. Rheological p ope ies o e-p ocessed samples we e es ed in e ms o MFI measu emen s using he ex uding plas ome e M201 (Haake) acco ding o EN ISO 1133. Samples we e condi ioned a 25% ela i e humidi y and hen ex uded a 150 °C h ough he 2 mm capilla y using he load o 100 N. The MFI co ela es o he polyme mass passing h ough a s anda d capilla y in an in e al o 10 minu es, a a gi en load. Quan i ica ion o wa e con en was ca ied ou by he Ka l Fische me hod (Me ohm AG). The me hod is based on he conduc ome ic de e mina ion o wa e e apo a ed om he shee in o he iodine solu ion and sulphu dioxide in me hanol. Yellowness was e alua ed using he CIE Lab. colou scale. Handy Colo (BYK Ga dne ) ins umen was applied and calib a ed wi h he whi e and black s anda ds. Measu emen was ca ied ou agains he whi e backg ound a he angle o 10°. Illumina ion ype o D65 co esponding o dayligh was applied. Yellowness YID, was calcula ed om he measu emen s o spec oscopic alues L, a and b. The ob ained alue was con e ed o he alue co esponding o he PVB shee wi h he s anda d hickness o 0.76 mm, which is ypical o applica ions in au omo i e indus y and in a chi ec u e. The mo-g a ime ic analysis (TGA) was de e mined by he mog a ime ic analyze TGA Q500 (TA Ins umen s, New Cas le, USA) in open pla inum c ucibles and weighed-in. Amoun o PVB sample o he mal analysis was app ox. 8 mg and measu emen s we e www.in echopen.com Ma e ial Recycling – T ends and Pe spec i es 140 aken in empe a u e in e al 20-500 °C, dT/d = 10 °C min-1 in p o ec i e ni ogen a mosphe e (150 mL min-1). GPC analyses we e conduc ed using a PLGPC-50 (Polyme Labo a o ies) equipped wi h a PL di e en ial e ac ome e (DRI) and on-line iscome e de ec o s (VIS). Analyses we e pe o med wi h a PL gel Mixed-C column (7.8 x 300 mm; Polyme Labo a o ies) a 30 °C wi h he mobile phase low a e o 1 mL/min. Te ahyd o u ane was used as he mobile phase. The column was calib a ed using na ow molecula weigh polys y ene s anda ds (Polyme Labo a o ies L d, Chu ch S e on, UK) wi h molecula weigh s anging om 580 o 451 000 g.mol-1 (gi en by supplie ). A 100 μL injec ion loop was used o all measu emen s. Fo he de e mina ion o molecula weigh , uni e sal calib a ion was applied. Da a p ocessing was pe o med wi h Ci us GPC, Mul i De ec o So wa e. The concen a ion was o abou 0.2 g /100 ml and samples we e dissol ed a oom empe a u e o 20 hou s unde s i ing. The combina ion o bo h ypes o de ec o s enabled o exac ly de e mine molecula weigh as well as de ec he PVB agg ega ion. 6.3 The in luence o kneading condi ions on he change o plas icized PVB shee p ope ies F om he heo y and p ac ice i is con i med ha he PVB e-p ocessing b ings abou he sho ening o mac omolecula chains, which induces he change o i s mechanical p ope ies. The esul s show ha inc easing o he e-p ocessing empe a u e b ough he lowe ing o mel igidi y (measu ed as MFI), lowe ing o ensile s eng h and s ain. These changes a e isualized in Figs. 3-4. The MFI alues a e shown in Fig.3. To sum up, he MFI inc eases wi h he inc easing o e- p ocessing empe a u e and he inc easing o o a ion speed sys ema ically up o 60 pm. Fig. 3. The change o MFI a he di e en condi ions o he kneading o PVB shee wi h wa e con en 0.5%. www.in echopen.com PVB Shee Recycling and Deg ada ion 141 I is consequence o he mo-oxida i e deg ada ion, which causes educ ion o polyme molecula weigh . Howe e , a he o a ion speed o 80 pm, he MFI alues beha e di e en ly. Deg ada ion o PVB mac omolecula chains (exp essed as inc easing o MFI) is educed a he empe a u es abo e 190 °C, which is indica ed by no ising o e en sligh d op o MFI (see Fig.3). The lowe ing o he deg ada ion a he highe o a ion speed (abo e 80 pm) is possible o explain by he sliding o polyme chains in he s essed mel esul ing in he lowe e ec o kneading. The esul s ob ained om he measu emen o ensile s eng h o he “d y” PVB samples (0.5 % mois u e con en ) in dependence on speed o he kneading sha a e shown in Figu e 4. A lowe empe a u es, deg ada ion o “d y” PVB is p opo ional o inc ease o he o a ion speed. Fo example, du ing p ocessing a 100 °C deg ada ion inc eased, which can be concluded om he lowe ing o s ess a b eak alues (shape o he cu e in conca e). On he o he hand, inc easing o empe a u e caused s aigh ening o his dependence and o he samples p ocessed abo e 160 °C he cu es exhibi he con ex cu ing. Minima on he cu es obse ed a o a ion speed o 60 pm and empe a u es 190 and 220 °C indica e, hence, he highes deg ada ion o PVB. Samples e-p ocessed by p essing we e used as a backg ound o he kneaded samples a he same empe a u es. Sligh inc ease o ensile s eng h, s ain a b eak, MFI and yellowness we e obse ed o he samples p essed o 10 minu es a he all es ed empe a u es. Fig. 4. Tensile s eng h o he e-p ocessed PVB shee a he di e en condi ions o he kneading o PVB shee wi h wa e con en 0.5%. 6.4 The ans o ma ion o he p ocess ene gy in o hea Du ing he PVB e-p ocessing on he B abende kneade he empe a u e o he kneading chambe was measu ed. The chambe was empe ed on he equi ed empe a u e, bu wi h on-going p ocess o kneading, he empe a u e sligh ly inc eased. The cou se o empe a u e www.in echopen.com Ma e ial Recycling – T ends and Pe spec i es 148 pa ame e s and deg ada ion was examined. The ob ained esul s show ha , based on he e alua ion o MFI and mechanical p ope ies, he op imal condi ions o PVB e-p ocessing by kneading occu a he empe a u e o abou 150°C and o a ion speed o kneade lowe han 60 pm. These conclusions a e in he good ag eemen wi h he measu emen o PVB yellowness. Below 150 °C yellowness emained almos unchanged and inc eased signi ican ly abo e his empe a u e. GPC measu emen s co obo a e he abo e conclusions showing minimal changes o PVB molecula weigh o his empe a u e. Inc eased amoun o wa e in PVB shee can ac as and addi ional plas icize imp o ing wo kabili y o polyme mel and dec easing his ene gy consump ion. Howe e he “we ” samples a e mo e suscep ible o hyd oly ic deg ada ion and comp omise decision has o be aken o ind he balance be ween hese wo e ec s. 10. Acknowledgemen This a icle was w i en wi h suppo o Ope a ional P og am Resea ch and De elopmen o Inno a ions co- unded by he Eu opean Regional De elopmen Fund (ERDF) and na ional budge o Czech Republic, wi hin he amewo k o p ojec Cen e o Polyme Sys ems ( eg. numbe : CZ.1.05/2.1.00/03.0111). 11. 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Glass union conce n: Resea ch and de eloping ins i u e o indus ial glass in Teplice, Issue C(1) Tupý M., Z oníček J., e al, (2008), P oblems o ecycling PVB shee used o p oduc ion lamina ed sa e y glass, Tomas Ba a Uni e si y, Facul y o Technology: Plas ics and Rubbe s, Vol.45, pp. 208-211 www.in echopen.com Ma e ial Recycling – T ends and Pe spec i es 150 Tupý M., Měřínská D., e al, ( 2010), In luence o wa e and magnesium ion on he op ical p ope ies in a ious plas icized PVB shee s, Accep ed o publica ion in Jou nal o Applied Polyme Science, Vol. 118, pp. 2100-2108 Tupý M., Měřínská D., (2010), Wa e and acid-base eac an s impac o adhesi es p ope ies o a ious plas icized PVB shee s, The Pape submi ed o Jou nal o Applied Polyme Science Tupý M., Měřínská D., e al, (2001), Windshield ecycling ocused on e ec i e sepa a ion o PVB shee , The Pape submi ed o Resou ces, Conse a ion and Recycling Wade B.E., D'e ico J., e al, (Ma 16, 2004), Polyme shee s and me hods o con olling adhesion o polyme shee s o glass, Uni ed S a es Pa en Applica ion US 20050208315 Z oníček J., (1999), Collec ion o indings close o PVB ex usion p ocess, Non-publish message, Re im-CZ, Zlín www.in echopen.com Ma e ial Recycling - T ends and Pe spec i es Edi ed by D . Dimi is Achilias ISBN 978-953-51-0327-1 Ha d co e , 406 pages Publishe InTech Published online 16, Ma ch, 2012 Published in p in edi ion Ma ch, 2012 InTech Eu ope Uni e si y Campus STeP Ri Sla ka K au zeka 83/A 51000 Rijeka, C oa ia Phone: +385 (51) 770 447 Fax: +385 (51) 686 166 www.in echopen.com InTech China Uni 405, O ice Block, Ho el Equa o ial Shanghai No.65, Yan An Road (Wes ), Shanghai, 200040, China Phone: +86-21-62489820 Fax: +86-21-62489821 The p esen ly common p ac ice o was es' land- illing is undesi able due o legisla ion p essu es, ising cos s and he poo biodeg adabili y o commonly used ma e ials. The e o e, ecycling seems o be he bes solu ion. The pu pose o his book is o p esen he s a e-o - he-a o he ecycling me hods o se e al ma e ials, as well as o p opose po en ial uses o he ecycled p oduc s. I a ge s p o essionals, ecycling companies, esea che s, academics and g adua e s uden s in he ields o was e managemen and polyme ecycling in addi ion o chemical enginee ing, mechanical enginee ing, chemis y and physics. This book comp ises 16 chap e s co e ing a eas such as, polyme ecycling using chemical, he mo-chemical (py olysis) o mechanical me hods, ecycling o was e i es, pha maceu ical packaging and ha dwood k a pulp and po en ial uses o ecycled was es. How o e e ence In o de o co ec ly e e ence his schola ly wo k, eel ee o copy and pas e he ollowing: Michael Tupý, Dagma Měřínská and Vě a Kašpá ko á (2012). PVB Shee Recycling and Deg ada ion, Ma e ial Recycling - T ends and Pe spec i es, D . Dimi is Achilias (Ed.), ISBN: 978-953-51-0327-1, InTech, A ailable om: h p://www.in echopen.com/books/ma e ial- ecycling- ends-and-pe spec i es/p b-shee - ecycling-and-deg ada ion-