IMPROVED COMMERCIAL CYANOACRYLATE COMPOUNDS

A. New Flexible Cyanoacrylates

New cyanoacrylate compounds exhibit good adhesion to various plastics and elastomeric surfaces, such as Mylar, copper foil, and vinyl films. These products show better impact resistance and good flexibility compared to standard cyanoacrylates, good resistance to cracking under flexing or bending, and a longer open time than that of standard products.

B. New Cure-Through-Gap Cyanoacrylates

Through changes in the manufacturing process, cyanoacrylates can now be highly pur­ified. This added purification step has led to the development of a group of materials that can cure through a gap without the typical reduction in shear strength and overall per­formance. More traditional formulations show a dramatic reduction in shear strength as the gap increases (see Fig. 6). Table 5 shows cure through a gap and the corresponding shear strength for these new, highly purified cyanoacrylates.

Time

Gap-filling

Regular

(h)

cyanoacrylate

cyanoacrylate

2

25

13

24

100

40

72

100

100

Table 6 Set Time Across a 0.004-in. Gap

Time (s)

Product

Surface-insensitive

Ethyl

viscosity (cP)

cyanoacrylate

cyanoacrylate

100

6-8

55

500

7-12

>60

1500

8-12

>60

8000

8-12

n. a.a

aNot applicable.

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