熱(re)封次(ci)數(shu)(shu)越多，熱(re)封強度越高(gao)，縱(zong)向熱(re)封次(ci)數(shu)(shu)取決于縱(zong)向焊棒(bang)的有效長度和袋長之比。
橫(heng)向熱(re)(re)(re)(re)封(feng)(feng)次(ci)(ci)數(shu)(shu)由機臺橫(heng)向熱(re)(re)(re)(re)封(feng)(feng)裝置的組數(shu)(shu)決定。良好的熱(re)(re)(re)(re)封(feng)(feng)，要求熱(re)(re)(re)(re)封(feng)(feng)次(ci)(ci)數(shu)(shu)至少達到兩次(ci)(ci)以上(shang)。相(xiang)同結構和(he)厚(hou)度(du)(du)(du)的復(fu)(fu)合膜，復(fu)(fu)合層(ceng)(ceng)(ceng)(ceng)(ceng)間(jian)剝(bo)離(li)度(du)(du)(du)越高，熱(re)(re)(re)(re)封(feng)(feng)強(qiang)(qiang)度(du)(du)(du)越大(da)；對于復(fu)(fu)合剝(bo)離(li)強(qiang)(qiang)度(du)(du)(du)低(di)的產品，焊縫破壞往(wang)往(wang)是焊縫處(chu)的復(fu)(fu)合膜先(xian)層(ceng)(ceng)(ceng)(ceng)(ceng)間(jian)剝(bo)離(li)，致(zhi)使(shi)由內面(mian)熱(re)(re)(re)(re)封(feng)(feng)層(ceng)(ceng)(ceng)(ceng)(ceng)獨立承受破壞拉力(li)，而面(mian)層(ceng)(ceng)(ceng)(ceng)(ceng)材料失去補(bu)強(qiang)(qiang)作用，致(zhi)使(shi)焊縫的熱(re)(re)(re)(re)封(feng)(feng)強(qiang)(qiang)度(du)(du)(du)由此大(da)為(wei)降低(di)；若復(fu)(fu)合層(ceng)(ceng)(ceng)(ceng)(ceng)間(jian)剝(bo)離(li)度(du)(du)(du)強(qiang)(qiang)，則不致(zhi)發生焊邊處(chu)層(ceng)(ceng)(ceng)(ceng)(ceng)問(wen)的剝(bo)離(li)，所測得的實際熱(re)(re)(re)(re)封(feng)(feng)強(qiang)(qiang)度(du)(du)(du)就人得多(duo)；在熱(re)(re)(re)(re)封(feng)(feng)內層(ceng)(ceng)(ceng)(ceng)(ceng)為(wei)PE或OPP時，熱(re)(re)(re)(re)封(feng)(feng)強(qiang)(qiang)度(du)(du)(du)就比同樣厚(hou)度(du)(du)(du)的BOPP好得多(duo)。