Ukukhetha Iziqinisi ze-PVC Zokusebenzisa Ipayipi Nephrofayili Ephumelelayo

Ngena kunoma yisiphi isitolo sokwakha noma sokuthuthukisa ikhaya, futhi uzothola i-PVC yonke indawo—kusukela kumapayipi athwala amanzi ezakhiweni kuya kumaphrofayili amafasitela ahlela imibono yethu. Lokho abantu abaningi abangakuqapheli ukuthi le thermoplastic eguquguqukayo isetshenziswa kabanzi yiqhawe elithule: iziqinisi ze-PVC. Ngezinqubo zokukhipha, ikakhulukazi, ukukhetha okulungileIsiqinisi se-PVCakuyona nje indaba yokuhlangabezana nezilinganiso zokukhiqiza; umehluko phakathi komkhiqizo oqinile, ohambisanayo kanye nalowo ohlulekayo ngaphambi kwesikhathi.

Okokuqala, ake siqonde ukuthi kungani iziqinisi zingaxoxiswana ngazo nge-PVC extrusion. Ngokungafani nezinye i-thermoplastics, i-PVC ine-Achilles' heel: ukuqina kokushisa okubi. Uma ishiswa kumazinga okushisa angu-160–200°C ajwayelekile nge-extrusion—ikakhulukazi emikhiqizweni eqinile njengamapayipi—i-PVC iqala ukukhipha i-hydrogen chloride (HCl). Lokhu kubangela ukusabela kweketanga lokuwohloka, okuholela ekushintsheni kombala (cabanga ngokuphuzi, bese kuba nsundu, bese kuba mnyama) kanye nokwehla okukhulu kwamandla omshini. Uma ingalawulwa, impahla iba buthakathaka futhi ingasetshenziswa, ingasaphathwa eyomshini we-HCl olimaza igesi. Yilapho iziqinisi ze-PVC zingena khona. Umsebenzi wazo oyinhloko ukuphazamisa le nqubo yokuwohloka—kungaba ngokuyinciphisa i-HCl, ukufaka esikhundleni ama-athomu e-chlorine angazinzile ku-PVC molecular chain, noma ukubamba ama-free radicals asheshisa ukuwohloka. Ngezicelo zamapayipi nephrofayili, ezidinga ukuqina kwesikhathi eside (ngokuvamile iminyaka engaphezu kwengu-50 yamapayipi okufaka amapayipi) kanye nokusebenza okuqhubekayo, isiqinisi esifanele asiyona nje into eyengeziwe; siyingxenye eyisisekelo yesakhiwo.

Uma kukhulunywa nge-extrusion, akuzona zonke iziqinisi ze-PVC ezidalwe zilingana. Ukukhetha kuncike ezicini ezifana nokushisa kokucubungula, uhlobo lomkhiqizo, izidingo zomthetho, kanye nezindleko. Ake sihlukanise izinhlobo ezivame kakhulu ezisetshenziswa ekukhiqizweni kwamapayipi kanye nephrofayili, kanye nezinzuzo zazo, ukungalungi, kanye nezicelo ezinhle kakhulu:

Iziqinisi ezisekelwe ku-leadsekuyisikhathi eside iwumsebenzi onzima embonini, ikakhulukazi kumapayipi namaphrofayili e-PVC aqinile. Ukukhanga kwawo kusekuzinzeni okuhle kakhulu kokushisa, ukumelana nesimo sezulu okuqinile, kanye nezindleko eziphansi. Izinhlanganisela ezifana ne-tribasic lead sulfate noma i-dibasic lead phosphite zivame ukusetshenziswa ekwakhiweni kwephakethe elilodwa okuhlanganisa izinto zokugcoba, okwenza kube lula ukuzihlanganisa nezinqubo zokukhipha. Ngezinhlelo zokusebenza ezingacacile, ezingezona ezokuthintana nokudla—njengemipayipi yokudonsa amanzi noma amaphrofayili angaphakathi—iziqinisi ezisekelwe ku-lead bezilokhu ziyisinqumo esithandwayo. Kodwa-ke, izinsuku zazo zibaliwe ezifundeni eziningi. Imithetho eqinile efana ne-REACH kanye ne-RoHS ikhawulela noma ivimbela izithasiselo ezisekelwe ku-lead ngenxa yokukhathazeka kwemvelo kanye nempilo. Ngenxa yalokho, abakhiqizi bashintsha ngokuya kwezinye izindlela, ikakhulukazi zemikhiqizo ethengiswa e-EU, eNyakatho Melika, nakwezinye izimakethe ezilawulwayo.

Iziqinisi ze-Calcium-zinc (Ca-Zn)Kuvele njengendlela ehamba phambili enobungani nemvelo esikhundleni se-lead. Lawa ma-compound angenabo ubuthi, angenabo ubuthi manje ayindlela ejwayelekile yezinhlelo eziningi zokukhipha, kufaka phakathi amapayipi amanzi aphuzwayo kanye namaphrofayili angaphandle. Izithambisi zesimanje ze-Ca-Zn, ezivame ukwakhiwa njengezinhlelo ezihlanganisiwe, zinikeza ukuzinza kokushisa okumangalisayo uma zihlanganiswa nezithasiselo ezisizayo njenge-epoxides noma ama-phosphites. Isibonelo, isithambisi se-Ca-Zn esisebenza kahle kakhulu (njenge-RJ-702 grade esetshenziswa kwezinye izinhlobo) ku-3.5 phr (izingxenye nge-resin eyikhulu) singavimbela ngempumelelo ukuphuzi ngisho nasemazingeni okushisa aphezulu okukhipha. Enye yezinzuzo ezibalulekile zezithambisi ze-Ca-Zn ukuhambisana kwazo nama-plasticizer anobungani nemvelo njenge-DOTP, okubalulekile ekuhlangabezaneni nezidingo ze-VOC ephansi kanye nezingenabo ubuthi. Kodwa-ke, zinemikhawulo: izinhlelo zendabuko ze-Ca-Zn zingabhekana nokuzinza kokushisa kwesikhathi eside ekugcineni kwezinga lokushisa lokukhipha (ngaphezu kuka-190°C) futhi zingadinga ukubhanqa ngokucophelela ukuze kugwenywe izinkinga ezifana nokuphuma kwepuleti noma ukuqeda okungekuhle kobuso. Lokho kusho ukuthi, intuthuko ekwakhiweni—njengokwengeza izingxenye ezihambisanayo—yenze iziqinisi ze-Ca-Zn ezisebenza kahle kakhulu zifanelekela izinqubo zokukhipha ezidinga kakhulu.

Iziqinisi ze-Organotinkuyisinqumo esiphambili sezinhlelo zokusebenza lapho ukucaca nokusebenza okuphezulu kungaxoxiswana ngakho. Ama-compound afana ne-methyltin noma i-octyltin anikeza ukuzinza kokushisa okumangalisayo, ukubonakala okuhle kakhulu, kanye nokufuduka okuphansi, okwenza abe mahle kakhulu kumaphrofayili e-PVC asobala noma amapayipi akhethekile. Aphinde ahambisane ne-FDA, yingakho esetshenziswa ezinhlelweni ze-PVC zokuxhumana nokudla, yize izindleko zawo eziphakeme zikhawulela ukusetshenziswa kwawo ekukhiqizweni kwamapayipi ajwayelekile kanye namaphrofayili. Ngezinqubo zokukhipha ezidinga ifasitela elibanzi lokucubungula (okungukuthi, ukuguquguquka okwengeziwe ekulawuleni izinga lokushisa), ama-organotin stabilizers kunzima ukuwanqoba. Kodwa-ke, intengo yawo—ngokuvamile ephindwe kathathu kuya kahlanu kunezinye izindlela ze-lead noma ze-Ca-Zn—asho ukuthi ngokuvamile agcinelwe imikhiqizo enenani eliphezulu kunamapayipi noma amaphrofayili ezimpahla.

Ukuze usize ukubona ngeso lengqondo ukuhwebelana, nansi ukuqhathanisa okusheshayo kwezinhlobo ezintathu eziyinhloko zokuzinzisa zezinhlelo zokusebenza ze-extrusion:

Manje, ake sishintshele ohlangothini olusebenzayo: indlela yokukhetha isiqinisi se-PVC esifanele senqubo yakho yokukhipha, kungakhathaliseki ukuthi wenza amapayipi noma amaphrofayili. Isinyathelo sokuqala ukuvumelanisa ukukhetha kwakho nezidingo zomthetho. Uma uthengisa e-EU, eNyakatho Melika, noma kwezinye izimakethe eziqinile, iziqinisi ezisekelwe ku-lead azikho etafuleni—qala nge-Ca-Zn noma i-organotin. Kumapayipi amanzi aphuzwayo, kuzodingeka futhi uqinisekise ukuhambisana nezindinganiso ezifana ne-NSF/ANSI 61, ebeka ukufuduka okuphansi kwezithasiselo.

Okulandelayo, cabanga ngezimo zakho zokucubungula. Amapayipi e-PVC aqinile adinga amazinga okushisa aphezulu okukhipha (180–200°C) kunamaphrofayili amaningi, ngakho-ke uzodinga isiqinisi esinokuqina okuqinile kokushisa. Uhlelo lwe-Ca-Zn oluhlanganisiwe olunama-synergists e-epoxide noma isiqinisi se-organotin esisebenza kahle kungaba ukukhetha okungcono lapha kunengxube ye-Ca-Zn eyisisekelo. Uma umugqa wakho wokukhipha usebenza ngesivinini esiphezulu noma unesikhathi sokungasebenzi njalo, funa iziqinisi ezinikeza ukuthambisa okuhle (ukunciphisa ukungqubuzana nokwakheka kokushisa) kanye nezakhiwo zokuvikela isikhathi sokungasebenzi. Isibonelo, amanye amafomula e-Ca-Zn aklanyelwe ukuvimbela ukubola kokwakheka kwe-die ngesikhathi sokungasebenzi isikhathi eside—okubalulekile ekugwemeni ukuhlanzwa okubizayo kanye nokukhubazeka komkhiqizo.

Izidingo zokusebenza komkhiqizo zingenye into ebalulekile. Amaphrofayili angaphandle adinga ukumelana ne-UV ukuvimbela ukushintsha kombala nokuwohloka okuvela elangeni, ngakho-ke khetha iphakheji yokuzinzisa equkethe izifutho ze-UV (njenge-benzotriazoles) noma iziqinisi zokukhanya kwe-amine ezivinjiwe (HALS). Kumapayipi azothwala uketshezi olubolayo (njengokukhipha amanzi ezimbonini), isiqinisi esinokumelana okuhle kwamakhemikhali—njengohlelo lwe-Ca-Zn olusekelwe ku-lead noma olusebenza kahle kakhulu—luzoba lubalulekile. Amaphrofayili acacile, ngakolunye uhlangothi, adinga isiqinisi esingathinti ukucaca, okukhomba ku-organotin noma iziqinisi ze-Ca-Zn ezicacile eziklanywe ngokukhethekile.

Izindleko zihlala zicatshangelwa, kodwa kubalulekile ukulinganisela izindleko zangaphambilini nokusebenza kwesikhathi eside. Nakuba iziqinisi ezisekelwe ku-lead zishibhile, izindleko zokungalandeli imithetho (izinhlawulo, ukubuyiselwa komkhiqizo) noma umonakalo wedumela zingadlula kakhulu imali eyongiwe. Iziqinisi ze-Ca-Zn zinikeza indawo enhle yezinhlelo zokusebenza eziningi: zingabizi kakhulu kune-organotin futhi zihambisana nemithetho yomhlaba wonke. Abakhiqizi abaningi bathola ukuthi ukutshala imali kusiqinisi se-Ca-Zn esihlanganisiwe sekhwalithi ephezulu kunciphisa izindleko zokukhiqiza ngokunciphisa amaphutha (njengokuphuzi noma izingxenye eziphukayo) nokuthuthukisa ukusebenza kahle kwenqubo.

Ukuze sibonise lezi zimiso ngokusebenza, ake sibheke isibonelo sangempela: ukwakheka kokukhishwa kwamapayipi amanzi aphuzwayo. Umgomo lapha ukudala ipayipi elingenabo ubuthi, elihlala isikhathi eside, futhi elihambisana ne-NSF/ANSI 61. Ukwakheka okuvamile kungafaka: i-resin ye-PVC-SG5 engu-100 phr, i-35 phr DOTP (i-plasticizer enobungani nemvelo), i-3.5 phr composite Ca-Zn stabilizer (ibanga lokusebenza kahle kakhulu), i-calcium carbonate eboshwe nge-20 phr (i-filler), kanye ne-0.3 phr EVA (i-compatibilizer). I-composite Ca-Zn stabilizer inikeza ukuzinza kokushisa okudingekayo ukuze imelane nokukhishwa ku-185–195°C, kuyilapho i-DOTP ne-EVA ziqinisekisa ukugeleza okuhle kokuncibilika nokuhambisana. Umphumela wokugcina ipayipi elihlangabezana nazo zonke izindinganiso zokuphepha, elinokuphela kobuso obubushelelezi, futhi ligcina izakhiwo zalo zemishini amashumi eminyaka.

Esinye isibonelo ukukhishwa kwephrofayili yamafasitela angaphandle. Lawa maphrofayili adinga ukumelana namazinga okushisa aphezulu okukhishwa kanye nokuvezwa yi-UV isikhathi eside. Ifomula evamile isebenzisa i-composite Ca-Zn stabilizer ehlanganiswe nama-UV absorbers kanye ne-HALS. Iphakheji ye-stabilizer yenzelwe ukuvimbela ukuwohloka kokushisa ngesikhathi sokukhishwa (170–185°C) kanye nokuguga okubangelwa yi-UV okuhamba kancane. Ukwengeza ingxenye ye-lubricant ku-stabilizer kusiza ukuthuthukisa ukugeleza kokuncibilika nokunciphisa ukungqubuzana, okuholela kumaphrofayili anomumo ohambisanayo kanye nobuso obucwebezelayo. Le fomula ihlangabezana nezidingo ze-REACH futhi iqinisekisa ukuthi amaphrofayili ngeke aphuzi noma aqhekeke ngisho nangemva kweminyaka eminingi yokuchayeka elangeni.

Okokugcina, kubalulekile ukuqaphela ukuthi ukukhetha okungcono kakhulu kokuzinza kuvame ukubandakanya ukubambisana nomhlinzeki onedumela elihle. Yonke imigqa yokukhipha ihlukile—imishini ehlukene, amazinga e-resin, kanye nemingcele yokucubungula kungathinta ukusebenza kokuzinza. Umhlinzeki omuhle uzosebenza nawe ukuze ahlele iphakheji yokuzinza ngokwezidingo zakho ezithile, ahlinzeke ngamaphepha edatha obuchwepheshe (i-TDS) kanye nokusekelwa endaweni. Bangakusiza futhi ukuthi uzulazule endaweni eyinkimbinkimbi yokulawula, uqinisekise ukuthi imikhiqizo yakho ihlangabezana nazo zonke izindinganiso zasendaweni nezamazwe ngamazwe.

Iziqinisi ze-PVC zingamaqhawe angadunyiswanga ekucutshungulweni kokukhipha amapayipi namaphrofayili. Ziguqula i-resin engazinzile ngokushisa ibe yinto eqinile, eguquguqukayo ebalulekile ekwakheni kwesimanje. Uma ukhetha isiqinisi se-PVC sokukhipha, gxila ekuhambisaneni nomthetho, izimo zokucubungula, izidingo zokusebenza komkhiqizo, kanye nebhalansi yezindleko. Eziningi zezinhlelo zokusebenza namuhla, iziqinisi ze-Ca-Zn ezihlanganisiwe zinikeza inhlanganisela engcono kakhulu yokusebenza, ukuhambisana, kanye nenani. Ngokuqonda izidingo zakho kanye nokusebenza nomhlinzeki othembekile, ungaqinisekisa ukuthi inqubo yakho yokukhipha isebenza kahle, imikhiqizo yakho ihlangabezana nezindinganiso eziphakeme kakhulu, futhi amakhasimende akho athola ukuqina akulindele.