Closed-cell PVC foamboard is a lightweight rigid material used primarily in the manufacture of signs and displays. It is considered robust for outdoor use, being immune to rain and resistant to wind and sunlight.

History

In 1912, the first patents for

polyvinyl chloride Polyvinyl chloride (alternatively: poly(vinyl chloride), colloquial: vinyl or polyvinyl; abbreviated: PVC) is the world's third-most widely produced synthetic polymer of plastic (after polyethylene and polypropylene). About 40 million tons of ...

(PVC) were filed in Britain and Germany. It was not until the early 1930s that PVC was able to be produced cheaply, limiting its marketable applications for the time.

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

helped make the substance popular, as manufacturers used it to make an assortment of items for soldiers. It was here that PVC's water resistance was shown to be an important property, and tools made from PVC were used in many marine applications. After the war, PVC was not a popular choice of materials in the marine industry due to its density. In the 1970s, the need for a strong, moisture-resistant material led to plastic manufactures working with PVC to make it lighter. This led to the creation of PVC foamboard, by combining PVC with

polyurea Polyurea is a type of elastomer that is derived from the reaction product of an isocyanate component and an amine component. The isocyanate can be aromatic or aliphatic in nature. It can be monomer, polymer, or any variant reaction of isocyanate ...

at the molecular level.

Processing

PVC foamboard is made up of an

interpenetrating polymer network An Interpenetrating polymer network (IPN) is a polymer comprising two or more networks which are at least partially interlaced on a polymer scale but not covalently bonded to each other. The network cannot be separated unless chemical bonds are bro ...

between PVC and

. Now, the manufacturing process has become much more involved. First, polyvinyl chloride and

are mixed together under controlled conditions. The mixture is then dispensed into a mold (commonly square as to make the foamboards). The filled mold is sealed by clamping the sides shut and then put into a large press where it is heated. After, a slab of solid material emerges from the mold. The material then undergoes a hot bath in order to expand it to a final density and is cured. The material is then ready to be cut into sheets of varying sizes and thickness, depending on purchaser requirements.

Properties

PVC foamboard is distinct from the extra-lightweight

foamcore Foamcore, foam board, or paper-faced foam board is a lightweight and easily cut material used for wikt:mount, mounting of photographic prints, as backing for picture frame, picture framing, for making scale models, and in painting. It consists ...

board, laminated of foam and card surfaces, used for indoor signage and modelling. Like PVC, closed-cell PVC foamboard is

solid Solid is a state of matter where molecules are closely packed and can not slide past each other. Solids resist compression, expansion, or external forces that would alter its shape, with the degree to which they are resisted dependent upon the ...

and has a very rigid structure. Where it differs is in its closed-cell foam structure, which makes it very light (as little as half the weight of solid PVC), highly resistant to moisture and some chemicals, and very easy to cut and shape. It also has

thermoplastic A thermoplastic, or thermosoftening plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling. Most thermoplastics have a high molecular weight. The polymer chains as ...

properties, and begins to soften at around . Typically, closed-cell PVC foamboard can be cut as easily as

wood Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulosic fibers that are strong in tension and embedded in a matrix of lignin t ...

, softened and shaped by immersing in boiling water or with a standard

heat gun A heat gun is a device used to emit a stream of hot air, usually at temperatures between , with some hotter models running around , which can be held by hand. Heat guns usually have the form of an elongated body pointing at what is to be hea ...

, and painted with standard automobile

paints Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...

. In addition, Closed-cell PVC foamboard is made up of polarized molecules otherwise known as dipoles. It has a very low moisture absorption. The mixture of polyvinyl chloride and

has a good bond strength. Closed-cell PVC foam takes solid shape due to its linear structure. However, due to this structure, it is more brittle than open-celled PVC foam. It is available in densities varying from . It has a low flammability rate. A universal cross-linked closed-cell PVC that was used in a comparison with three heat-resistant cross-linked had a glass temperature of 83.2 °C. However, there are issues using PVC that can affect one's health and safety when in use.

Common uses

Closed-cell PVC foamboard is mainly used for industrial and manufacturing purposes. The material is primarily used in the manufacturing of signs and displays which are used for promotion ads, as well as road signs. Its appealing material properties have made it popular among the makers of

scale model A scale model is a physical model that is geometrically similar to an object (known as the ''prototype''). Scale models are generally smaller than large prototypes such as vehicles, buildings, or people; but may be larger than small protot ...

s and theatrical props. Builders who create yachts and composites used for experimental aircraft are typically found using PVC foamboard. This type of PVC foamboard is well resistant to weather and sunlight, and can thus be used to protect other, more damage-prone products.

Issues

One drawback to PVC materials is that hot working them produces noxious fumes containing

hydrochloric acid Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...

and potentially even

dioxins Dioxins and dioxin-like compounds (DLCs) are a group of chemical compounds that are persistent organic pollutants (POPs) in the environment. They are mostly by-products of burning or various industrial processes or, in the case of dioxin-like PC ...

. These are a respiratory hazard in a workshop, and the acid fumes are so serious that they may damage equipment. Some heat-based processes, notably

laser cutting Laser cutting is a technology that uses a laser to vaporize materials, resulting in a cut edge. While typically used for industrial manufacturing applications, it is now used by schools, small businesses, architecture, and hobbyists. Laser cutt ...

, are generally considered impossible, owing to the equipment risk. Where PVC materials are cut by laser, this is a highly specialized process requiring adapted machines and acid-specific fume extraction and filtering.

References

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