Kwatanta LLDPE da LDPE.

Polyethylene mai ƙarancin yawa mai layi, wanda ya bambanta da polyethylene mai ƙarancin yawa na gabaɗaya, saboda babu rassan sarkar dogaye. Layin layi na LLDPE ya dogara ne akan hanyoyin samarwa da sarrafawa daban-daban na LLDPE da LDPE. LLDPE yawanci ana samar da shi ta hanyar haɗakar ethylene da manyan olefin alpha kamar butene, hexene ko octene a ƙananan zafin jiki da matsin lamba. Polymer na LLDPE wanda tsarin haɗakar ƙwai ke samarwa yana da kunkuntar rarraba nauyin ƙwayoyin halitta fiye da LDPE na gabaɗaya, kuma a lokaci guda yana da tsarin layi wanda ke sa ya sami halaye daban-daban na rheological.

kaddarorin kwararar narkewa

Halayen kwararar narkewar LLDPE sun dace da buƙatun sabon tsari, musamman tsarin fitar da fim, wanda zai iya samar da samfuran LLDPE masu inganci. Ana amfani da LLDPE a duk kasuwannin gargajiya don polyethylene. Ingantaccen shimfidawa, shigar ciki, tasirin tasiri da juriyar tsagewa sun sa LLDPE ya dace da fina-finai. Kyakkyawan juriyarsa ga fashewar damuwa ta muhalli, juriyar tasirin zafi mai ƙarancin zafi da juriyar warpage sun sa LLDPE ya zama mai jan hankali ga bututu, fitar da takarda da duk aikace-aikacen ƙira. Sabuwar aikace-aikacen LLDPE shine a matsayin ciyawa don cike shara da rufin tafkuna.

Samarwa da Halaye

Samar da LLDPE yana farawa da masu kara kuzari na ƙarfe masu canzawa, musamman na nau'in Ziegler ko Phillips. Sabbin hanyoyin da aka dogara da masu kara kuzari na ƙarfe na cycloolefin wani zaɓi ne na samar da LLDPE. Ana iya aiwatar da ainihin aikin polymerization a cikin masu kara kuzari na ruwa da iskar gas. Yawanci, ana haɗa octene da ethylene da butene a cikin mai kara kuzari na ruwa. Ana haɗa Hexene da ethylene a cikin mai kara kuzari na ruwa. Resin LLDPE da aka samar a cikin mai kara kuzari na ruwa yana cikin nau'in barbashi kuma ana iya sayar da shi azaman foda ko kuma a ƙara sarrafa shi zuwa pellets. An ƙirƙiri sabon ƙarni na super LLDPE bisa ga hexene da octene ta hanyar Mobile, Union Carbide. Kamfanoni kamar Novacor da Dow Plastics sun ƙaddamar. Waɗannan kayan suna da babban iyaka na tauri kuma suna da sabon damar don aikace-aikacen cire jaka ta atomatik. Resin PE mai ƙarancin yawa (ƙasa da 0.910g/cc.) shi ma ya bayyana a cikin 'yan shekarun nan. VLDPES yana da sassauci da laushi wanda LLDPE ba zai iya cimmawa ba. Halayen resins gabaɗaya ana nuna su a cikin ma'aunin narkewa da yawa. Ma'aunin narkewar yana nuna matsakaicin nauyin kwayoyin resin kuma galibi ana sarrafa shi ta hanyar zafin amsawa. Matsakaicin nauyin kwayoyin halitta ba ya dogara da rarraba nauyin kwayoyin halitta (MWD). Zaɓin mai haɓaka yana shafar MWD. ​​Yawan yana ƙayyade ta hanyar yawan comonomer a cikin sarkar polyethylene. Yawan comonomer yana sarrafa adadin rassan sarka gajere (wanda tsawonsa ya dogara da nau'in comonomer) don haka yana sarrafa yawan resin. Mafi girman yawan comonomer, ƙarancin yawan resin. A tsarin, LLDPE ya bambanta da LDPE a cikin adadi da nau'in rassan, LDPE mai matsin lamba mai yawa yana da dogayen rassan, yayin da LDPE mai layi yana da gajerun rassan kawai.

sarrafawa

LDPE da LLDPE suna da kyakkyawan kwararar rheology ko narkewa. LLDPE yana da ƙarancin ƙarfin yankewa saboda kunkuntar rarraba nauyin kwayoyin halitta da kuma rassan sarkar gajeru. A lokacin yankewa (misali extrusion), LLDPE yana riƙe da ɗanko mafi girma kuma saboda haka yana da wahalar sarrafawa fiye da LDPE tare da ma'aunin narkewa iri ɗaya. A cikin extrusion, ƙarancin ƙarfin yankewa na LLDPE yana ba da damar sassauta damuwa na sarƙoƙin ƙwayoyin polymer cikin sauri, kuma don haka rage ƙarfin halayen jiki ga canje-canje a cikin rabon fashewa. A cikin tsawaita narkewa, LLDPE ya bambanta a ƙarƙashin nau'ikan iri daban-daban Gabaɗaya yana da ƙarancin danko a cikin sauri. Wato, ba zai taurare ba lokacin da aka shimfiɗa shi kamar LDPE. Ƙarawa tare da ƙimar nakasa na polyethylene. LDPE yana nuna ƙaruwa mai ban mamaki a cikin danko, wanda ke faruwa ta hanyar ɗaure sarƙoƙin kwayoyin halitta. Ba a lura da wannan lamari a cikin LLDPE ba saboda rashin dogon rassan sarƙoƙi a cikin LLDPE yana kiyaye polymer daga haɗuwa. Wannan kadarar tana da matuƙar mahimmanci ga aikace-aikacen fim mai siriri. Domin fina-finan LLDPE na iya yin fina-finai masu siriri cikin sauƙi yayin da suke riƙe da ƙarfi da tauri mai yawa. Ana iya taƙaita halayen rheological na LLDPE a matsayin "mai tauri a cikin yanke" da "mai laushi a cikin faɗaɗa".