Adhesives for exterior use include those subjected to

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Unformatted text preview: products such as in laminated lumber, edge-glued lumber, and finger-joined lumber designed for wet or exterior service conditions. Adhesives for exterior use include those subjected to repeated wetting and drying and continuous use under high humidity, but does not include below-ground, ground-contact, and marine use. This standard is not restricted to a specific type of adhesive. CSA O112.10, “Evaluation of Adhesives for Structural Wood Products (Limited Moisture Exposure)” Adhesives covered by this standard shall be used to bond solid wood materials in structural wood products intended for limited moisture exposure applications. Limited moisture is described as conditions where the bond line of the adhesive is stressed to design-load levels only when the moisture content of the surrounding wood is 19% or less (dry service). The moisture content of the wood might occasionally be greater than 19% (e.g., due 3 of 10 to accidental wetting); however, the wood is not expected to resist design stress levels when wet. Bond lines exposed to moisture content exceeding 19% have comparable performance to unexposed bond lines, provided that the surrounding wood is allowed to return to dry service conditions (“dry service conditions” means the average moisture content does not exceed 15% during the year, and the maximum moisture content is 19% or less). Standard(s) Table 1. Performance Requirements for Physical Properties of Animal Glues for Wood Property Moisture content - Type I only Jelly strength - Types I and III only Viscosity - Types I and III only Unit Requirement % 12.0 ± 3.0 bloom grams mPa·s Glue grades Type I Type III 85 110 135 165 190 220 250 280 315 350 380 Viscosity - Type II only • at 29°C • at 21°C 85 110 135 165 190 220 250 280 315 350 380 Jelly Viscosity strength 75-94 ≥ 3.2 95-121 ≥ 3.6 122-149 ≥ 4.0 150-177 ≥ 4.7 178-206 ≥ 5.2 207-236 ≥ 7.5 237-266 ≥ 8.5 267-298 ≥ 9.6 299-330 ≥ 10.5 331-362 ≥ 11.5 363-394 ≥ 12.6 mPa·s ≥ 1 800 ≤ 50 000 pH of glue n/a 6.7 ± 1.0 Foam • Types I and III • Type II mm % ≤ 25 ≤ 50 Odour and keeping qualities n/a no odour of decomposition Ash - Types I and III only % ≤5 Grease - Types I and III only % ≤3 MPa % ≥ 19 average shear strength ≥ 50 average wood failure % ≤ 15 Shear strength - compression loading Hygroscopicity - Type II only 4 of 10 Table 2. Performance Requirements for Physical Properties of Starch Glues for Wood Property Unit Requirement Shear strength - compression loading (Type II only) MPa ≥ 14 average shear strength Plywood shear strength (Type I only) kPa ≥ 2 000 average shear strength Storage life - after six months at 21°C to n/a meets the requirements of CSA O112.2 24°C (Type II only) Table 3. Performance Requirements for Physical Properties of Casein Glues for Wood Property Unit Requirement Shear strength - compression loading MPa ≥ 19 average shear strength Plywood shear strength (Types I and II only) • dry strength kPa • wet strength Liquid working life at 21°C to 24°C (Types I...
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