Barrier films

Description

A material, such as plastic, paper or metal, that is impermeable to gas or liquid. Modern barrier films are usually made from lightweight transparent plastic sheets whose goal is to reach the barrier properties of a metal or glass. Metal sheets, such as Aluminum foil have good barrier properties. They are often laminated with polyethylene and/or nylon to provide tear and corrosion resistance. Some plastics work well as vapor barriers (Polyvinylidene chloride, polyester, rigid Polyvinyl chloride, nylon, Polychlorotrifluoroethylene, Polyvinyl fluoride) while other are best for moisture (polyvinyl chloride, Regenerated cellulose, Polyethylene, Polypropylene, Polymethyl methacrylate (Hatchfield 2002). Multiple materials are laminated for optimized barrier properties. I these cases the center layer usually provides the vapor barrier covered with layers to provide strength and tear resistance. then often the outside contains low density polyethylene to provide a heat sealing capabilities.

Comparable values are as follows:

Tradenames	Single layers (1 mil thick)	Oxygen transmission	Water vapor transmission
	Ethylene-vinyl acetate (EVA)	0.8-2.8 ml/m²d	22-84 gms/m²/day
Oxyshield	biaxial Nylon-6	18.6-39 ml/m²d
	Low Density Polyethylene (LDPE)	7000-8500 ml/m²d	15-22 (11-28) gms/m²/day
	High Density Polyethylene (HDPE)	2300-3100 ml/m²d	6 (2.9-7.2) gms/m²/day
	Oriented Polypropylene (OPP)	1550-2500 ml/m²d	0.5 (5.2-13) gms/m²/day
Aclar-RX	Poly(chlorotrifluoroethlene) (PCTFE)	62	0.16-0.4 gms/m²/day
	Polyester (PET)	31-93 ml/m²d	4.0-39 gms/m²/day
	Oriented Polystyrene (OPS)	4350-6200 ml/m²d	108-155 gms/m²/day
Teflon	Poly tetrafluoroethylene	0.55 ml/m²d	1 gms/m²/day
Saran	Polyvinylidene chloride (PVDC)	2.3-14 ml/m²d	1.5-3 gms/m²/day
Archipress; Cryovac	Poly vinyl alcohol (EVOH)	0.08-0.19 ml/m²d	0.4-0.8 gms/m²/day
	Cellophane	90	2740-6850 gms/m²/day
Tradename	Laminated layers	Oxygen transmission	Water vapor transmission
	Metallized OPET	0.16-1.7 ml/m²d
	PVOH coated OPP	0.31 ml/m²d
	Metallized biax Nylon-6	0.78 ml/m²d
	PVDC coated OPET	4.7-7.8 ml/m²d	5 gms/m²/day
	PVDC coated OPP	4.7-9.3 ml/m²d
	PVDC coated biax Nylon-6	4.7-7.8 ml/m²d
	Metallized OPP	19-160 ml/m²d
Hy-Bar	LLDPE/EVOH	2 ml/m²d	1.5-3 gms/m²/day
Aclar	PE/PET/PCTFE/PE	14 ml/m²d	0.028 gms/m²/day
Escal	PE/OPP/EVOH/OPP/PE	0.05 ml/m²d	0.01 gms/m²/day
Cadpak	PE/Nylon	0.08 ml/m²d (>4 mils thick)	0.008 gms/m²/day
	EVOH/nylon	2.3 ml/m²d (3 mil thick)
Filmpak 1193	PET/PE/EVOH/PE	0.1 ml/m²d (1 mil thick)	0.45 gms/m²/day
MarvelSeal 360	PE/Nylon/Al foil/Nylon/PE	0.01 ml/m²d (5 mils thick)	0.009 gms/m²/day
Dri-Shield 2000	PE/Al foil/PET/Al foil/PET	xx (3.6 mils thick)	<0.54 gms/m²/day

Synonyms and Related Terms

barrier plastic; barrier film; barrier board; vapor barrier; vapour barrier; air barrier; air infiltration barrier; Marvelseal® 360; Marvelseal® 470; Aclar® [AlliedSignal]; Filmpak 1193; Film O-Rap [Bell Fibre]; ESCAL; EVOH/nylon; Sperrschichtmaterial (Deut.); matériau barrière (Fr.); barreira (Port.)

Resources and Citations

• Collins, Chris. “Barrier Films.” The Natural History Museum, 1999. Link

• P.Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002.

• J.Burke, "Vapor Barrier Films" WAAC Newsletter, Vol 14, No. 2, 199, 13-17.

• Boise Cascade Paper Group, The Paper Handbook, Boise Cascade, Portland OR, 1989

• Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 578

• Conservation Support Systems, Catalog, 1997

• Theodore J. Reinhart, 'Glossary of Terms', Engineered Plastics, ASM International, 1988

• Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000