Ntiaj Teb Tsum Ntawm Kev Tiv Thaiv Ib Puag Ncig

Cov khoom no tau sib haum tau zoo heev nrog ntau cov ntaub qhwv thiab tuaj yeem siv los ua qhov sib txuas, yas, thiab muag khoom. Nws cov txheej txheem yog qhov muaj zog, thiab feem ntau tsis cuam tshuam cov yam ntxwv vulcanization ntawm cov khoom siv roj hmab, uas ua kom cov roj hmab zoo ntawm cov roj hmab vulcanized. Mas siv rau hauv kev tsim cov roj hmab cov khoom lag luam xws li cov log tsheb, cov hlau ntoo, roj hmab yob, cov xov roj hmab thiab cov roj hmab uas muaj cov tebchaw, thiab lwm yam.