ʻaneʻane hiki ke hoʻohaʻahaʻa ʻia nā plastik a pau ke ʻike ʻia i ke kukui ultraviolet, e like me ka lā a i ʻole nā kukui fluorescent. Hiki ke hōʻino ʻia i ka wā o ka hana ʻana a i ʻole ma hope o ka hoʻokomo ʻia ʻana o ka huahana, a ʻo kona mau hōʻailona e like me ka brittleness, discoloration, a me ka nalowale o nā waiwai kino e like me ka ikaika hopena, ka ikaika tensile, a me ka waihoʻoluʻu—ʻo ia mau mea a pau e kōkua i ka pōkole o ke ola o nā plastics. Nā kukui UV ʻO kahi laʻana o ka hoʻohaʻahaʻa ʻana i kēlā me kēia lā ʻo nā noho lau nahele, e ʻulaʻula a lilo i mea palupalu i ka wā ma muli o ka pōʻino o ka plastic.
ʻO nā mea hoʻohui UV stabilizing nā pūhui i hoʻohui ʻia e hakakā i ka pōʻino plastik a hoʻonui nui i ke ola o ka huahana hope. Hoʻohui ʻia nā stabilizer UV ma nā pae haʻahaʻa loa, maʻamau 0.1 - 0.5% o ka polymer. Hiki ke hoʻohui pinepine ʻia kēia mau mea hoʻohui me ka polymer kumu i ka wā o ke kaʻina hana a i hoʻomākaukau ʻia ma ke ʻano he masterbatch. Nui nā mea hoʻohui ma ka mākeke no ka hoʻopaʻa ʻana o UV, me ka Amcor's UV inhibitor stabilizer Amshield.
He aha ka photooxidation?
ʻO ka hōʻino ʻana o nā plastics i hoʻokumu ʻia e ke kukui UV ka hopena o kahi kaʻina kemika i kapa ʻia he photooxidation a i ʻole photodegradation. Hoʻohaʻahaʻa ke kukui UV i nā mea paʻa kemika e noho nei i loko o ke kaulahao polymer, hoʻonāwaliwali i ka plastic ma ka hoʻemi ʻana i kona kaumaha molekala, ka hopena o ka nalowale o ka ikaika a me nā hōʻailona ʻē aʻe e like me ka mea i kūkākūkā mua ʻia. ʻO ka hoʻohaʻahaʻa molekula, e like me ke kiʻi-oxidation, he mea nui ka hoʻomaopopo ʻana i kēia mau kaʻina hana a pehea e pale aku ai iā lākou!
ʻOkoʻa ka pale ʻana o UV o nā polymers i pale ʻole ʻia e ke ʻano a me ke ʻano. ʻOi aku ka maʻalahi o kekahi mau plastic i ka hoʻonanea-kiʻi ma muli o ko lākou kūkulu ʻana a me nā pūʻulu hana. ʻO nā mea paʻa hiki ke loaʻa i ka photooxidation, ʻo ia nā mea paʻa carbon{3}}nitrogen, e like me nā nitriles, amides, a me nā amine; carbon -oxygen bonds, e like me nā ethers, esters, ketones, carboxylic acids, etc.; kalapona -paʻa kalapona; oxygen -oxygen bonds, like me peroxides; a me ka hydrogen hydrogen, e like me nā amides a me nā amine.
Nā ʻano o nā UV Stabilizers
No ka pale ʻana i ke kiʻi-kaʻina hoʻohāhā a hoʻomalu i ka plastik mai nā kukuna UV ʻino, hoʻohana ʻia nā mea hoʻopaʻa UV. Ma muli o ka UV stabilizer i hoʻohana ʻia, hiki ke hāʻawi ʻia ka pale UV ma nā ʻano like ʻole. Ma keʻano laulā, ʻike ʻia nā ʻano mea hoʻohui maʻamau ma ke ʻano he UV absorbers, quenchers, a i ʻole HALS, a ma kekahi mau hihia, ʻoi aku ka nui o hoʻokahi mea hoʻohui e hiki ke hoʻohana i ka pae i makemake ʻia o ka hoʻopaʻa ʻana o UV.
UV absorbers: Me ka lawa kukui hoʻokomo, sensitive hui pūʻulu hana (kapaia chromophores) i loko o ka polymer e hoʻopuka i nā radical manuahi ma o ke ʻano o nā hopena. E like me ka inoa i hōʻike ʻia, ʻo kēia ʻano o ka UV stabilizer e hoʻopaʻa i ka uila UV e pale i ka hoʻomaka ʻana o nā kiʻi-hoʻona. I ka manawa e komo ai ka wela mai ke kukui UV, e hoʻopau ʻia ma o nā kaulahao polymer. ʻO ka ʻeleʻele kahi mea hoʻoheheʻe UV maikaʻi loa, no laila ua hoʻohui pinepine ʻia nā pena, nā mea pena a i ʻole nā ʻeleʻele kalapona elemental e pale i nā huahana plastik mai nā kukuna UV. ʻO Benzotriazoles a me hydroxyphenyltriazines kekahi mau hiʻohiʻona o nā UV absorbers.
Quenchers: ʻO ke kaʻina hana hoʻohāhā-kiʻi he nui nā hopena e hoʻopuka ai i nā radical manuahi e hoʻopili me nā mea paʻa he nui i loko o ke kaulahao polymer, e luku ana i ka pono o ka plastic. Hana nā Quenchers ma ke kinai ʻana i ka ikehu i hana ʻia i ka wā o ke kiʻi -panehe hoʻohāhā, a no laila, hauʻoli lākou i ka hoʻihoʻi ʻana i ke kūlana honua kahi i hiki ʻole ai ke hoʻolaha i ke kiʻi-hoʻohāhā ʻana e hoʻopuka ai i nā radical manuahi. ʻO nā nickel quenchers kahi laʻana o kēia ʻano o ka UV stabilizer.
HALS: ʻO ka Amine Light Stabilizer a i ʻole HALS he mea hoʻokūpaʻa UV e hoʻopaʻa a paʻa i nā radical manuahi i hana ʻia i ka wā o ka -oxidation kiʻi, e pale ana iā lākou mai ka hana ʻana me ka hale polymer. ʻOkoʻa ke ʻano o ka HALS, akā maʻamau he 2,2,6,6-tetramethylpiperidine ring structure.
