熱(re)(re)(re)封次數越多，熱(re)(re)(re)封強度越高，縱向(xiang)熱(re)(re)(re)封次數取(qu)決于縱向(xiang)焊棒的有效長度和(he)袋長之比。
橫向熱(re)(re)封(feng)(feng)(feng)次數(shu)由(you)機臺(tai)橫向熱(re)(re)封(feng)(feng)(feng)裝置(zhi)的(de)(de)組數(shu)決定。良好的(de)(de)熱(re)(re)封(feng)(feng)(feng)，要(yao)求熱(re)(re)封(feng)(feng)(feng)次數(shu)至少達(da)到(dao)兩次以上。相(xiang)同結構和厚度(du)(du)(du)的(de)(de)復(fu)合(he)膜，復(fu)合(he)層(ceng)(ceng)間剝離度(du)(du)(du)越高(gao)，熱(re)(re)封(feng)(feng)(feng)強(qiang)(qiang)(qiang)(qiang)度(du)(du)(du)越大；對(dui)于復(fu)合(he)剝離強(qiang)(qiang)(qiang)(qiang)度(du)(du)(du)低的(de)(de)產(chan)品，焊(han)(han)縫(feng)(feng)破壞往往是焊(han)(han)縫(feng)(feng)處的(de)(de)復(fu)合(he)膜先(xian)層(ceng)(ceng)間剝離，致使(shi)由(you)內面(mian)熱(re)(re)封(feng)(feng)(feng)層(ceng)(ceng)獨立承受破壞拉力，而面(mian)層(ceng)(ceng)材料失去補(bu)強(qiang)(qiang)(qiang)(qiang)作用，致使(shi)焊(han)(han)縫(feng)(feng)的(de)(de)熱(re)(re)封(feng)(feng)(feng)強(qiang)(qiang)(qiang)(qiang)度(du)(du)(du)由(you)此大為(wei)(wei)降低；若復(fu)合(he)層(ceng)(ceng)間剝離度(du)(du)(du)強(qiang)(qiang)(qiang)(qiang)，則不致發生焊(han)(han)邊(bian)處層(ceng)(ceng)問的(de)(de)剝離，所測得(de)的(de)(de)實際(ji)熱(re)(re)封(feng)(feng)(feng)強(qiang)(qiang)(qiang)(qiang)度(du)(du)(du)就人得(de)多(duo)(duo)；在熱(re)(re)封(feng)(feng)(feng)內層(ceng)(ceng)為(wei)(wei)PE或(huo)OPP時(shi)，熱(re)(re)封(feng)(feng)(feng)強(qiang)(qiang)(qiang)(qiang)度(du)(du)(du)就比同樣厚度(du)(du)(du)的(de)(de)BOPP好得(de)多(duo)(duo)。