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PHYSICAL PROPERTIES

VICAL Cell cast acrylic sheet

VICAL is the registered trademark for acrylic plastic sheet produced by Vical S.A de C.V. In its natural form, Vical acrylic sheet is an optically clear, transparent , lightweight material having outstanding weatherability, high impact resistance, good chemical resistance, and excellent thermoformability and machinability. In addition to colorless, Vical can be specially produced in colors. Note: Vical has aesthetic advantage over any known competitor because of its sparkling, color free edges, a property known as "low edge color".

VICAL acrylic sheet is a lightweight, rigid thermoplastic material that has many times the breakage resistance of glass. Vical is ultraviolet light absorbing and therefore very weather resistant withstanding exposure for many years without losing its surface gloss or mechanical properties. Vical sheets can be easily fabricated using wood working tools. It can be sawed, machined, thermoformed, and cemented using readily available companion products. Vical et may be perceived as "transparent wood" which can be formed making it ideal for a wide range of APPLICATIONS. SOURCES OF SUPPLY

AVAILABILITY VICAL acrylic sheet is available in thicknesses from .1.00" to 4.00" . Sheets can be furnished masked with heavy duty domestic masking paper. Thickness tolerances are the tightest in the industry and by far the most uniform. Each sheet is given a nine point inspection for thickness and is recorded on a label on the sheet itself and the invoice to the distributor.

WEATHER RISISTANCE Acrylic plastic offers weather resistance unmatched by any other plastic material or most man-made materials. VICAL sheet will withstand exposure to blazing sun, extreme cold, sudden temperature changes, salt water spray and other harsh conditions. It will not deteriorate after many years of service. VICAL sheet has beenwidely accepted for use in furniture, heavy machined transparent, periscope blanks, prison glazing, architectural, marine tanks and safety applications. Note that the stability against deterioration from the weather elements pertains to clear acrylic. Colored acrylics are subject to fading to varying degrees depending on the colorants used.

DIMENSIONAL STABILITY Although VICAL acrylic sheet will expand and contract due to changes in temperature and humidity, it will not shrink with age. Some shrinkage occurs when VICAL GP sheet is heated to forming temperature.

LIGHT WEIGHT VICAL sheet is less than half the weight of comparable thicknesses of glass.

STRENGTH AND STRESSES Although the tensile strength of VICAL GP acrylic sheet is 10,000 psi at room temperature (ASTM D 638), stress crazing (tiny fissures) can be caused by continuous loads below this value. Continuously imposed design loads should not exceed 1500 psi. Localized, concentrated stresses must be avoided particularly near drilled holes or edges. For this reason, and because of thermal expansion and contraction, large sheets should never be fastened with bolts; installing Vical in frames is more desirable. All thermoplastic materials-including VICAL sheet-gradually lose tensile strength as temperatures approach the maximum recommended for continuous service, which, for VICAL sheet, is 180 °F. Deformation is a function of thickness and so this data is less relevant as thickness increases.

EXPANSION AND CONTRACTION Plastics are organic materials which naturally expand and contract more than inorganic materials. VICAL sheet will expand 3 times as much as metals, and 8 times as much as glass, and therefore the coefficient of expansion and contraction must be considered by architects and designers. A 48" panel will expand and contract approximately .002" for each degree F change in temperature. Another quick calculation is Vical will expand (or contract) 1/8" per running foot per 100° F. In outdoor use, where summer and winter temperatures differ as much 100°F, a 48" sheet will expand and contract approximately 1/4". Sash rabbets must be of sufficient depth to allow for expansion as well as for contraction. For additional more specific information LET'S NetTALK!

VICAL sheet also absorbs water when exposed to high relative humidities, resulting in expansion of the sheet. At relative humidities of 100%, 80%, and 60%, the dimensional changes are 0.3%, 0.2% and 0.1%, respectively.

HEAT RESISTANCE VICAL sheets can be used at temperatures from 40°F up to + 200 °F, depending on the application. It is recommended that temperatures not exceed 180°F to 200°F for continuous service.

LIGHT TRANSMITTANCE Clear (colorless) VICAL GP acrylic sheet has a light transmittance of 92%.

CHEMICAL RESISTANCE VICAL acrylic sheet has excellent resistance to many chemicals including:

	solutions of inorganic alkalies such as ammonia
	dilute acids such as sulfuric acid
	aliphatic hydrocarbons such as hexane

VICAL sheet (Clear) is FDA approved for direct contact with food. It neither affects food nor is affected by food and is excellent for food containers such as commercial food bins or consumer designer bowls or cups.

It is attacked, in varying degrees, by:

	aromatic solvents such as benzene and toluene
	chlorinated hydrocarbons such as methylene chloride and carbon tetrachloride
	ethyl and methyl alcohols
	some organic acids such as acetic acid
	Iacquer thinners, esters, ketones and others
	OTHER CHEMICALS

FORMABILITY VICAL sheet will soften gradually as temperature increases above 210°F. When heated to temperatures ranging from 340 °F to 380°F, Vical becomes soft and pliable enabling it to be formed into many desired shapes using inexpensive wood molds. The optimum forming temperature within this range depends on thickness and desired depth of draw. VICAL sheet will typically shrink 1.5% when heated without a frame. As the sheet cools, stiffness or rigidity will be restored and it will retain the formed shape.

CUTTING AND MACHINING VICAL sheet may cut by sawing or routing with power equipment saws. It can be drilled, routed, filed and machined much like wood or brass. Keeping cutting tools cool is recommended to

minimize the buildup of localized stresses due to heat which can lead to stress crazing (fissure cracks). Well sharpened and "true" tools are essential to prevent heat build up and subsequent crazing and possible edge chipping.

SOURCES OF SUPPLY For more detailed information on cutting and machining LET's NetTALK!

CEMENTING VICAL sheet can be cemented to itself using common solvent cements or polymerizable cements (SOURCES OF SUPPLY). The most critical factor is the condition of the edge to be cemented. The edge must be properly machined to have a square flat surface and no stresses (a network of fine cracks). Note: Always polish after cementing. Do not cement flame polished parts as crazing is almost certain to occur. Annealing parts prior to cementing is recommended. For additional information on cementing Vical to itself or dissimilar materials LET's NetTALK!

ANNEALING Annealing is recommended to eliminate stresses caused by machining and/or polishing. VICAL sheet may be annealed at 180°F with the heating and cooling times determined by sheet thickness. An approximate guideline is: annealing time in hours equals the sheet thickness in millimeters and the cooldown period equals the sheet thickness in millimeters. For example, 25mm (1") VICAL sheet would be heated for 3 hours at 180°F and slowly cooled for 24 hours.

FLAMMABILITY VICAL sheet is a combustible thermoplastic and is classified by UL as a slow burning plastic. Precautions should be taken to protect the material from flames and high heat sources. Generally speaking, the same fire precautions that are observed in connection with the use of any ordinary combustible material should be observed when handling, storing or using Vical.

Other properties related to flammability:

Burning rate is 4.6 cm per minute por 2 mm thickness) according to ASTM D 635.

Flame spread is 140 jor 3mm thickness) according to ASTM E 84, or 110140 (or 3mm6mm thickness) according to CAN4S102.2.

Smoke density: Measured by ASTM D 2843 is 10.3%.

Selfignition temperature is 910°F (for 1.5mm thickness) when measured in

accordance with ASTM D 1929.

While these test data are based on small scale laboratory tests frequently referenced in various building codes, these tests do not duplicate actual fire conditions.

The products of combustion, if sufficient air is present, are carbon dioxide and water and is therefore non-toxic. However, in many fires, sufficient air will not be available and toxic carbon monoxide will be formed as it will from other common combustible materials. Burning Vical acrylic does not produce either excessive quantities of smoke or gases more toxic than those produced by burning wood or paper. The concentration of carbon monoxide and/or carbon dioxide released by burning Vical acrylic is a factor of the quantity of Vical acrylic involved and the conditions of burning.

SURFACE HARDNESS The surface of plastics is softer than glass. Therefore, reasonable care should be exercised in handling and cleaning VICAL sheet similar to the care given to acrylic finishes on automobiles, appliances or any fine furniture. Use dampened soft cotton cloths such as discarded undershirts or chammies to clean Vical and allow to air dry. Simonize wax can be used to polish scratches. For additional information on the maintenance of Vical contact PlasticsOnLine's LET'S NetTALK!

ELECTRICAL CONDUCTIVITY VICAL sheet has many desirable electrical properties and continuous outdoor exposure has little effect on these properties. It is a good insulator with surface resistivity higher than that of most plastics. This property also causes it to build a static charge which makes dust particles and lint somewhat difficult to remove. Anti-Static compounds are available for use where static build up and high dust concentration create a cleaning problem. Cleaning dirty static charged parts can be best achieved using Joy dishwashing liquid in the same concentration as washing dishes. It is an excellent destatisizing agent.