ຄຸນສົມບັດປ້ອງກັນຄວາມຊຸ່ມຊື່ນຂອງແຜ່ນອາລູມິນຽມ

ແຜ່ນອາລູມິນຽມມີຄຸນສົມບັດປ້ອງກັນຄວາມຊຸ່ມຊື່ນທີ່ດີ. ເຖິງແມ່ນວ່າ pinholes inevitably ຈະປາກົດໃນເວລາທີ່ຄວາມຫນາຂອງແຜ່ນອາລູມິນຽມແມ່ນຫນ້ອຍກ່ວາ 0.025mm., ເມື່ອສັງເກດເຫັນກັບແສງສະຫວ່າງ, the moisture-proof properties of ແຜ່ນອາລູມິນຽມ with pinholes are much stronger than those of plastic films without pinholes. This is because the polymer chains of plastics are widely spaced apart from each other and cannot prevent water vapor from penetrating.

Moisture permeability of aluminum foil and plastic films

Material type	Moisture permeability/g·(m2·24h)-1	Material type	Moisture permeability/g·(m2·24h)-1
0.009mm plain aluminum foil	1.08~10.70	0.09mm polyethylene	7
0.013mm plain aluminum box	0.60~4.80	0.1mm polyethylene	4.8
0.018 mm plain aluminum foil	0～1.24	0.02mm PVC	157
0.025mm plain aluminum foil	0～0.46	0.065mm PVC	28.4
0.03~0.15mm	0	0.095mm PVC	41.2
plain foil cellophane	50~70	/	/

When the thickness of aluminum foil is small enough, pinholes will inevitably appear. The minimum thickness for pinholes is generally considered to be 0.038mm. Due to improvements in rolling technology and materials, this thickness has been reduced to 0.025mm. Tests have also proven that the vent diameter is critical. When the diameter is less than 5um, oxygen and water vapor are not transmitted within the measurable range.