I recently had a call from a gentleman trying to write a process for high speed production line. \u00a0\u00a0They had tested one of our cyanoacrylates (instant adhesives) and found it extremely fast. The adhesive developed strength so rapidly that they planned to implement an inline packaging operation within seconds of bonding.\u00a0 The call came because he noted on the technical data sheet that the product took 24 hours to achieve full cure.<\/p>\n
\u201cSo which is it INSTANT?\u00a0 Or 24 HOURS?\u201d\u00a0 Well, the answer is Yes and Yes.<\/p>\n
Have you ever bonded your fingers with instant adhesive?\u00a0 You know it happens in an instant!\u00a0\u00a0 Don\u2019t try this \u2013 but if you left the bond alone for 24 hours it would be even stronger.<\/p>\n
If you bond something -other than your fingers please\u2026say a steel coupon, with instant adhesive, then test that sample on an Instron a few seconds later \u2013 you will see that the bond is strong.\u00a0 If you bond another steel coupon and clamp it into the Instron 24 hours later the bond would be even stronger.\u00a0 Then try one more \u2013 bond the coupons and let them sit for 48 hours \u2013 you\u2019ll have the same result as you did at 24 hours.\u00a0 So we know that strength continues to develop for 24 hours.\u00a0 This doesn\u2019t mean you have to sit and look at it for 24 hours.\u00a0 If sufficient strength is achieved for handling, the cure can and will continue while you are not looking.<\/p>\n
In other cases, the production line adhesive strength development is not as important as the tack free or skin over time.\u00a0 For example, MS Polymer adhesives can take 72 hours to cure. However, skin over time is much faster.\u00a0 Cure times with moisture cure products are often listed in terms of depth per hour.\u00a0 But again, you don\u2019t need to sit and watch.\u00a0 Identify the strength required to handle or identify tack free time and use that as the determining time for the next process to occur in your manufacturing facility.<\/p>\n
Another phenomenon in strength development occurs with any polymer created.\u00a0 For example, UV curing adhesives cure quickly with high intensity UV light.\u00a0 They do not continue to cure once the light is off. But they do continue to develop strength. Keep in mind that unless there is some secondary cure mechanism like anaerobic, or moisture, UV curable adhesives ONLY cure while exposed to UV light.\u00a0 So why do they continue to develop strength?\u00a0 The slight strength development that continues to occur for up to 24 hours isn’t really curing \u2013 but strength continues to increase.\u00a0 All those polymer chains just need some time to relax into the proper place.<\/p>\n
Test for full strength after the manufacturers’ listed cure time.\u00a0 Then correlative testing can be done via an inline QC test.\u00a0 For example, if full strength is 3000psi after 24 hours \u2013 what does that correlate to at your QC test time?<\/p>\n
When it comes to packaging a product that has not completely cured, it is good to note that depending on the type of adhesive, different by-products of curing can be given off.\u00a0 It is a good idea to test the packaged product to ensure sensitive plastics or electronics will not be adversely affected if packaged prior to complete cure.<\/p>\n","protected":false},"excerpt":{"rendered":"
Production Line Adhesives Need Precise Cure Times I recently had a call from a gentleman trying to write a process for high speed production line. \u00a0\u00a0They had tested one of our cyanoacrylates (instant adhesives) and found it extremely fast. The adhesive developed strength so rapidly that they planned to implement an inline packaging operation within […]<\/p>\n","protected":false},"author":5,"featured_media":11855,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[614,829],"tags":[113],"class_list":["post-1473","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-adhesive-types-2","category-cyanoacrylate-adhesives-2-pt-br","tag-production-line-adhesive"],"acf":[],"yoast_head":"\n