Underwater Adhesive Process

3,607,542 5 6 Monomer' a~cyano- Filler l Paste gramsFlow Example acrylate I' oetyl CaCO, 2' heptyl fair SiO. 0.3 CaCO, 2.7 excellent heptyl 3.4 heptyl CaCO, 2.6 sio, 0.1 to 0.2 CaCO, 3.4 heptyl CaCO, 2.7 hexyl CaC0.:s amyl CaCO, 3.5 fair butyl CaCO, 201' 110' 187' 100' 175' 25t1' 2.5 good 2.0 very thin nonyl l' Surfaces·· Average Bond Strength in Tension (p .s. i.) 8' CaC0.:s 2.7 SiO, 0.05 CaCO, 2.7 Si0 2 0.05 CaCO, 2.7 0.05 SiO, CaCO, 2.7 10 475" 410' 609' 710 11 rubber/steel 74' rubber/wood 3 If glasS/glass 7' 5 15 d 225' 135' 112' 253' 80' 150' 420' 20 and fluid 10 deeyl II cyclohexyl 12 ethoxy- 210 885 270 ethyl 13 isobutyl 14 isopropyl 15 2-ethyl- SiO, CaCO, SiO, CaCO, SiD, CaCO, 0.1 2.7 0.05 2.7 0.05 2.7 30 260 360 310 hcxyl 16 propyl' 17 ethyl' 18 methyl" 19 hexyl 20 2-ethyl- 0.05 SiD" CaCO, 2.6 sio, 0.1 CaCO, 2.7 0.1 Si0 1 CaCO, 2.7 sio, 0.1 BaCO, 2.7 0.1 SiO! CaSO. 2H,0 2.0 25 200 35 200 75 75 40 750 210 hexyl 21 butyl 22 allyl n-hcxyl and n-arn yl 24 trifluoroisopropyl 0.1 SiDI CaSO, I>H,O 3.0 5i0 2 0.1 CaCO, 2.7 SiD, 0.1 BaCO, 2.7 400 SiO, 0.1 CaC0 3 2.7 155 SiD,! 80 45 250 50 0.1 **AII examples adhere two stainless steel surfuces under fresh water. unless otherwise specified. '"Salt water used in this sample. 'I Immediate sealing. r. Sealing after a J -minute immersion. I' Sealing after a 2-minute immersion. " G lass slides broke. precluding reading, ,. Bond strengths as high as 580 p.s.i. obtained in individual tests. r Peel strength; rubber peeled from steel and wood substrates. " Held together for only I minute under water. hexyl-o-cyanoarcylate (pH 3.7), 3.6 parts by weight of calcium carbonate and 0.2 part by weight of "Cab-O-Sil," additional bonds are prepared under water as set forth in examples 25 to 32. In these examples all test specimens (except those with corroded or painted surfaces) are prepared for adhesive bonding by vapor degreasing for 5 minutes with trichloroethylene. This is followed by a hoI water rinse and then a final wash in methyl ethyl ketone. The procedure for each test (run) in examples 25 to 32 is as follows: a. Water in a container is regulated at the indicated temperature; b. Test specimens are submerged in the water; c. Adhesive is applied to bonding surfaee of one submerged test specimen; d. Adhesive is spread over entire bonding area by sliding test specimens over one another; e. Moderate hand pressure (approximately I pound) is applied between bonding surfaces for a time interval A; f. Bonded test specimens removed from water and placed in Dillon Dynamometer for pull tests; g. Load applied between test specimens; time interval B is the interval between conclusion of time interval A and application of load. The adhesive cure begins immediately upon contaet with water. Up to 2 minutes are available following application to spread the adhesive and bring the bonding surfaces together. All ingredients are stored in closed containers. The hcxyl-ocyanoacrylate is packaged in a polyethylene bottle. Cardboard cans are used to package the amorphous silica and the calcium carbonate. The mixed adhesive paste can be readily applied from its collapsible squeeze tube container for a period up to 4 hours. The following portions of Federal Test Standard 175, Adhesive Methods of Testing, are used for performing the physical tests: Method 1011.1 - Tensile Properties of Adhesives Method 1033.1-T - Shear Strength Properties of Adhesives by Tensile Loading. All tests for each example are performed on the same day with the same adhesive batch. The bond area for each test is one square inch. 7.8 grams of mixed adhesive composition is adequate for approximately 20 thin film tests. The aluminum alloy employed in each of examples 25 through 32 is aluminum alloy AA6061-T6 anodized per Mil-A-625 and having a surface roughness of 32, In each of said examples the steel is steel per Mil-S-16216, Grade HY-80; in examples 25, 28, 29, 31 and 32 the surface roughness is 32; in examples 26 and 30 the surface bonded is badly oxidized to a finish of approximately 125; in example 27 the surface bonded is painted per NAYORD USTD 52, System No. 48 (antifouling). 55 EXAMPLE 25 Steel is adhered to anodized aluminum alloy submerged in a 3 percent solution of salt (NaCl) water having a temperature 60 of 70° F. Ten repetitions produce the following results: h Paste delivered as a glob through a polyethylene tube to one of the two steel surfaces held under water. i All silica (5iO,) used in the examples in conjunction with the filler is amorphous silica. j In each example 3.0 grams of monomer are used, except in Example 1 where 6.1 grams of monomer are used; in Example 23,1.5 grams of each monomer are ernptoyed. Eaeh"!~J isE~~f!l~s~?.tJ1~r~is~.~.!'£ifi~d,•..._ ..•_ . 65 A' B" 45 37 Heptyl-a-cyanoacrylate admixed with calcium carbonate 45 75 (CaC03 ) and amorphous silica (as in the examples) was also 45 48 found to form strong bonds (under water) of aluminum to alud 45 81 minum. In the same manner wood/wood and rubber/rubber 70 45 55 44 45 bonds were formed. Although there may be some variation in J 45 57 K maximum tensile or shear strengths and the optimum pH may h 45 42 differ, strong bonds are likewise formed under water for 45 62 glass/glass, plastic/plastic (phenol/formaldehyde thermoset 75 47 45 plastic) and combinations of the noted substrates, e.g. ~topl/~h1fT1i"l1m nl~~ti£"l,:"b~~ ~nn'W()O:{\(f1~inted 'steel, .. Tim" I., ""f·ntHI,!, In of/man: seccirnen bond H Tensile Strengths [p.s.i.} 90 375 190 325 425 275 450 125 475 Average 61.5 Time in seconds (unlc,,'( otherwise