III. Cov khoom siv thiab kev tsim cov txheej txheem txheej txheej
Khob hauv ob sab phlu txheej yog txheej tiv thaiv uas tiv thaiv sab hauv ntawm daim ntawv khob dej khov. Cov khoom siv feem ntau siv hauv ob sab phlu yog raws li hauv qab no.
A. Hom khoom siv rau txheej txheej ntawm cov ntawv khob, xws li polyester, polyethylene, thiab lwm yam
1. Polyethylene
Polyethylene yog dav siv nyob rau hauv cov txheej txheej ntawm cov ntawv khob vim nws cov dej tsis zoo thiab cov roj resistant, nrog rau nws cov nqi qis. Thoes ua rau nws haum rau zus tau tej cov loj-scale ice cream khob khob.
2. Polyester
Polyester txheej tuaj yeem muab kev tiv thaiv ntau dua. Yog li, nws tuaj yeem tiv thaiv tsw ntxhiab, roj nkag, thiab nkag mus rau oxygen. Yog li ntawd, polyester feem ntau yog siv nyob rau hauv zoo dua high-end ntawv khob.
3. PLA (polylactic acid)
PLA muaj cov dej tsis zoo, tab sis nws cuam tshuam nrog kev tiv thaiv ib puag ncig thiab tau siv dav hauv qee lub khw muag khoom siab.
B. Qhia txog cov txheej txheem tsim khoom, xws li cov txheej txheem tshwj xeeb txheej thiab vuam
Kev tsim cov txheej txheem ntawm txheej txheej rau daim ntawv khob yog raws li hauv qab no:
1. Cov txheej txheem tshwj xeeb
Nyob rau hauv cov txheej txheem ntawm cov ntawv khob, cov txheej txheej hauv ob sab phlu yog dav siv los xyuas kom meej cov dej tsis zoo thiab cov roj resistant ntawm cov khob. Cov txheej txheem kom ntseeg tau tias cov txheej txheem sib npaug sib npaug thoob plaws lub khob tag nrho yog siv cov cuab yeej niaj hnub txhaj tshuaj. Ua ntej, cov sediment raug ntes thiab npaj, thiab tom qab ntawd txhaj rau hauv lub khob ntawv.
2. Vuam
Qee zaum, cov txheej txheem tshwj xeeb yog qhov tsis tsim nyog. Nyob rau hauv cov ntaub ntawv no, lub puab txheej ntawm lub khob ntawv yuav siv tau thaum tshav kub kub sealing (los yog vuam) tshuab. Qhov no yog txheej txheem ntawm nias ntau txheej ntawm cov ntaub ntawv sib txawv ua ke, ua kom lub hauv ob sab hauv thiab lub khob lub cev nruj ua ke. Los ntawm kev muab cov txheej txheem tiv thaiv txhim khu kev qha, cov txheej txheem no ua kom lub khob ntawv ruaj khov rau qee yam thiab yuav tsis xau.
Cov saum toj no yog ib qho kev qhia txog cov khoom siv thiab kev tsim cov txheej txheem rau txheej txheej ntawm daim ntawv khob. Cov ntaub ntawv xws lipolyethylene thiab polyester yog haum rau ntau qib ntawm daim ntawv khobs. Thiab cov txheej txheem tshwj xeeb txheej thiab vuam txheej txheem tuaj yeem ua kom zoo thiab ua haujlwm ntawm daim ntawv khob hauv ob sab phlu.