PVC Boards

Description

Lightweight rigid or flexible foamed boards made of Polyvinyl chloride. Most have sandwich-like structures of smooth outer skin and interior fine-cell foam. PVC closed cell foam boards are made by expanded foam extrusion using nitrogen gas. All products have a maximum service temperature of 50-60 C and a coefficient of linear expansion of < 0.08 mm/m-k.

Examples of some types of PVC boards are:

Product name	Comments	Density	Shore hardness	water absorption (%)	min ; max thickness (mm)	Company link
FOREX® Classic	Standard lightweight product; PE film on one side; available in white	0.7	40-44	<1	2 ; 19	3A Composites
FOREX® Print	More economical (30% less); less rigid and resistant; PE film on one side; available in white	0.5	>32	<1	2 ; 19	3A Composites
FOREX® Color	Cannot be used outdoors; PE film on one side; tinted in 9 colors	0.6	37	<1	3 ; 8 (10, 19 black only)	3A Composites
KomaCel®	Standard product; available in white	0.55-0.7	55-77	<0.2	4 ; 30	Kommerling
KomaTex®	Free foamed sheet, (no outer skin); available in white and black	~0.6	48-55	<0.3 - 3.0	1 ; 25 (white), 2 ; 19(black)	Kommerling
KomaLite®	More economical form of KoamTex; available in white and black	0.5			3 ; 6	Kommerling
Sintra	Standard lightweight product, low gloss (satin); has two release liners - one on each side; is printable on both sides; available in 9 colors	0.5-0.9			1 ; 12.7	3A Composites
Sintra Vers (formerly ePVC)	More economical and versatile; low gloss finish; available in white and black				3 ; 6	3A Composites
Sintra Construct	Designed for fabrication; extra rigidity and screw retention; better for shelving; available in white and black				6 ; 19	3A Composites
Celtec		0.58	55

Synonyms and Related Terms

foam sheet; foam board

Commercial products: [Kommerling, USA] KomaCel® Plus; KomaTex®; KomaLite® [3A Composites USA] Sintra; Sintra Vers (formerly ePVC); Sintra Construct [3A Composites, Airex AG, Switzerland] FOREX® Color; FOREX® Classic; FOREX® Print; [Palram] Palight

Applications

Graphic substrates (signs)
Case interior elements: mount making (risers, fabric wrapped backers, decks), labels
Storage: open shelves, trays (not in proximity to sensitive objects)

Personal Risks

Harmful to health when inhaling or ingesting dust and vapors during unpacking, sawing, grinding and thermoforming.
Ensure good ventilation and dust extraction on processing machines and at other places where dust may develop.
Hazardous thermal decomposition products: Hydrochloric acid (HCl), Carbon dioxide (CO2), Carbon monoxide (CO)

Collection Risks

Some PVC board products pass the Oddy test, while some fail.
Some PVC boards pose risk to sulfide-sensitive materials and possibly to materials sensitive to acetic acid.
Some rigid, unplasticized PVC construction boards give off a sulfur containing heat stabilizer (2-ethylhexyl thioglycolate [2-EHTG]) that can tarnish silver (publication forthcoming). Other specific brands of PVC construction board, namely Komacel (Kommerling) and e-PVC (3A Composites) are safe for use in exhibition casework as they do not contain 2-EHTG.
KomaCel is more recently approved for permanent use (vs KomaTex).
KomaTex has a heat stabilizing component which leaches out over time.

Environmental Risks

Degrades with heat and light, first discoloring and becoming brittle, then producing hydrochloric acid gas.
If heated or burned, may form carbon monoxide or phosgene (carbonyl chloride).
Production and incineration of PVC can introduce toxic chlorinated organic chemicals into the environment (e.g. dioxin).
The Red List of Building Materials lists PVC and discourages it use.

Physical and Chemical Properties

PVCs are generally fire resistant.
Not biodegradable but may be recycled in some locations.

Working Properties

Properties of the same product can change over time and may depend on geography.
All can be cut, machined, joined, and receive paint.

To join:

mechanical fasteners (screws)
Tetrahydrofuran (solvent weld): need proper extraction, PPE; quick and fast, not much clean up, perhaps more solid bond than 3M epoxy
adhesive: 3M DP605 2 part epoxy - may need to score or rough up smooth surfaces to get good adhesion

Wood, acrylic, and fabric can be adhered to PVC boards:

laminated acrylic to PVC with 3M Scotch-Weld DP605NS two-part epoxy - good for heavier, stronger decks because acrylic has tapping properties
To adhere fabric to PVC: ATG 695, Instabond C (double-coated polyester film), 3M 465 Clear Tape

To prevent open-celled edges from showing:

spackle edge before painting
cut at 45 deg angle and miter join
mechanically fasten L angle frame around it so the edge is covered

Fairly rigid, but will sag; not intended to be a weight-bearing substrate. Thus, need for supports like U channels or ribs.

Takes acrylic paint relatively well.

Takes DTS (direct to substrate) inks really well.

Presence and number of protective release liners may be used to quickly identify products (i.e. Sintra always has two liners).

Forms and Sizes

Most come in full sheet sizes (4x8 feet), usually available in at least white and black.
Check product brochures/table for specific info on colors, finishes, sizes available.
Need a trusted supplier that does not fill orders with multiple products.

Resources and Citations

Canosa et al. (Swedish National Heritage Board), Characterization of Emissions from Display Case Materials, 2019, https://www.diva-portal.org/smash/get/diva2:1324017/FULLTEXT01.pdf

Samide and Smith, “Assessing the Suitability of Unplasticized Poly(Vinyl Chloride) for Museum Showcase Construction,” JAIC, 2020.

Samide, Liggett, Mill and Smith, “Relating volatiles analysis by GC–MS to Oddy test performance for determining the suitability of museum construction materials,” Heritage Science 6 (47), 2018.

Samide and Smith, “Analysis and quantitation of volatile organic compounds emitted from plastics used in museum construction by evolved gas analysis–gas chromatography–mass spectrometry,” Journal of Chromatography A, Sept. 2015.