QUANTITATIVE STUDY: THE EFFECTS OF SIZED MATERIALS AND “DRYING TIME” IN THE USE OF LASCAUX 360 HV AS A LINING ADHESIVE
Danielle Allard, & Kenneth B. Katz
THE SUPPORT USED AS THE original canvas was a light-weight Belgian linen. The Belgian linen was stretched, wetted and restretched again. After the second stretching, one coat of Liquitex Acrylic Gesso was brushed on to simulate a ground. A few days later, Rohm and Haas Acryloid B-72 (10% in xylene) was applied to the reverse of half of the Belgian linen samples, followed by a second coat one day later. The lining canvas in all cases was a woven polyester, P & S #39. The polyester was stretched and half the samples were coated with 10% B-72 in xylene. One coat of B-72 was brushed on each side of the polyester samples.
The lining adhesive was used undiluted from its container and applied to the polyester through a fiberglass window screen using a squeegee. A second coat was applied in the same manner, approximately two hours after the first application. The final application of adhesive (1 hour and 24 hours drying time) was arranged so that all samples could be lined at the same time and under the same conditions.
The samples were lined on a Nascor Convectron Vacuum hot table using Mylar (.001mm), as a membrane. The vacuum as measured on the table gauge was approximately 4 inches of Hg. (By “feeling” the top membrane, the vacuum pressure was determined not to be very strong but adequate.) The temperature of the adhesive, as measured with a digital temperature meter, was approximately 131°F (26°C). It was kept constant for 5 minutes. The samples were rolled once using a nappy paint roller. The table was then cooled down to room temperature. The samples were on the table for a total of 2 hours.
The samples were lined to produce 1 “overlap for lap/shear testing and 3” overlap for peel testing. Four samples were lined for each category and labeled as follows:
The first letter represents the type of test: P for peel test, L for lap/shear test.
The number represents the elapsed time between the final application of the adhesive and the actual lining: 1 for 1 hour, 24 for 24 hours.
The capital letter represents the polyester: S for sized with B-72, U for unsized. The lower case letter represents the linen: s for sized with B-72, and u for unsized.
As an example, P1 Su represents peel test of the samples lined 1 hour after the final application of Lascaux 360 HV. The polyester was sized and the Belgian linen unsized.
After lining, the samples were cut into 1″ wide strips and sent to the Nordson Corporation testing facility in West Lake, Ohio where peel and lap/shear tests were performed on an Instron 1115 Tester. The conditions were as follows for the test:
50 Kg load cell
crosshead speed 2mm/min.
chart speed 2mm/min.Lap/shear test:
50 Kg load cell
crosshead speed 1cm/min.
chart speed 1 cm/min.
All samples were climatized to 72°F and 55% Rh.