Optium Museum Acrylic

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Description

(Tru Vue®) Extruded acrylic sheet composed of a UV-blocking Polymethyl methacrylate substrate with double-sided anti-reflective and anti-static coatings. It has been in use since at least 2004.

Acrylic glazing is chosen over glass for conservation purposes due to its shatter-resistance, light weight, and ease of machining. Optium Museum Acrylic is chosen over other types of acrylic sheets based on its proprietary coatings that impart high UV protection, anti-reflective and anti-static properties, and improved hardness that resists incidental marring.

Applications

Optium Museum Acrylic is produced for use as glazing within frames and can be joined to create seamed flat panels[1] as well as three-dimensional vitrines and display cases.

Though acrylic sheet such as Optium Museum Acrylic is commonly and effectively used for traveling displays, it should not be used in hermetically sealed cases, as acrylic is an inadequate barrier to water vapor.[2]

Pressure-mounts for textiles often use lightweight and shatter-resistant acrylic glazing.[3] Testing on Optium Museum Acrylic has determined that the coatings are inert and thus the glazing is safe for direct contact with collection items.[4]

The TruVue website has a large portfolio of projects which have used Optium Acrylic Glazing for object display cases, large-scale charcoal on paper, wall niches, framed tapestry, Japanese screens, climate-controlled packages for chalk on paper, library cabinet doors, and more.

Personal Risks

While the product has been deemed non-hazardous, fabricators are advised to wear eye protection when cutting the acrylic sheet.

The acrylic base is a combustible thermoplastic, so caution should be taken around flames and sources of high heat.[5]

Collection Risks

Links to Oddy Test results posted on AIC Wiki Materials Database Pages for individual materials below

Environmental Risks

Acrylic resins are not commonly recycled. PMMA can be extracted at high purity from acrylic mixtures but only with the use of lead, complicating any positive environmental impact.[6]

Physical and Chemical Properties

Technical specifications from TruVue[7]
Substrate: Abrasion Resistant UV Filter Acrylic
Coating: Double-Sided Anti-Reflective
Reflection: <1.6% (double sided)
Transmission: >98% (total)
UV Block: up to 99% of 300nm to 380nm UV rays

Avoid high temperatures. Acrylic sheet auto-ignites at 445°C/833°F and softens at 99°C/210°F.[8]

The polymethyl methacrylate of the acrylic sheet is soluble in esters, ketones, aromatic and chlorinated hydrocarbons.[9]

Working Properties

Sheets of Optium Museum Acrylic can be scored and snapped as long as they are 3.0mm or 4.5mm thick.[10] Sheets of 6mm thickness must be cut with a saw, as laser cutting can disrupt the coatings. TruVue recommends an H-Series panel saw with a Plex-Cut PC860 saw blade from Everlast.[11]

Heat-based fabrication methods like flame polishing, line bending, or thermo-forming will harm the coating and are not advised.

Miter joints are recommended for assembling 3-D structures, as butt joints require the removal of the coating on the uncut sheet so that the adhesive doesn't mar it.

TruVue recommends the following adhesives: Acrifix 2R1074 Vitrine (Evonik Industries), Weld-on 40 (IPS), PS-30 (Caseway Industrial Products), or Acrifix 192 (Evonik Industries).

This section's information and further details on coating removal, annealing, and edge polishing are available within the Case Fabrication Guidelines document.

Forms and Sizes

Information from the TruVue Acrylic Collection Fact Sheet
Thickness Maximum Size Sq. Feet/Sheet Approx. Weight/Sheet
6.0mm
(¼")
72" x 120"
(3048mm x 1829mm)
60 sq. ft
(5.57 sqm)
89 lbs/40.37kg
1.5 lbs per ft²
7.2kg per m²
4.5mm
(3/16")
72" x 96"
(2438mm x 1829mm)
48 sq. ft
(4.46 sqm)
54 lbs/24.5kg
1.13 lbs per ft²
5.5kg per m²
3.0mm
(⅛")
48" x 96"
(2438mm x 1219mm)
32 sq. ft
(2.97 sqm)
22 lbs/9.98kg
0.7 lbs per ft²
3.2kg per m²
Sizes available in 3mm sheets 16" x 20" 20" x 24" 24" x 32" 32" x 40" 36" x 48" 40" x 60" 48" x 96"

Resources and Citations

  • Kate Aguirre, contributed information, MWG group, 2020.