# What substance makes tape SO sticky!?

**URL:** <https://boards.straightdope.com/t/what-substance-makes-tape-so-sticky/107183>\
**Category:** Factual Questions\
**Created:** [May 4, 2002, 12:30am UTC](https://boards.straightdope.com/t/what-substance-makes-tape-so-sticky/107183 "2002-05-04T00:30:35Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![the\_great\_dalmuti](https://avatars.discourse-cdn.com/v4/letter/t/b2d939/32.png) [@the\_great\_dalmuti](https://boards.straightdope.com/u/the_great_dalmuti)\
**Post date:** [May 4, 2002, 12:30am UTC](https://boards.straightdope.com/t/what-substance-makes-tape-so-sticky/107183/1 "2002-05-04T00:30:35Z")

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Regular scotch tape, clear packaging tape, etc. What substance makes it so sticky??? Is it a glue type substance made of horse hooves (like white glue) or some sort of strange chemical compound?  
Please tell me the chemical name and its source (animal, vegetable, mineral, or synthetic substance).  
Thanks!

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**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\
**Post date:** [May 4, 2002, 1:25am UTC](https://boards.straightdope.com/t/what-substance-makes-tape-so-sticky/107183/2 "2002-05-04T01:25:12Z")

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From 3M more than you ever wanted to know about the physics and chemistry of adhesive tapes.

[Fundamentals of Adhesion](http://www.3m.com/us/mfg_industrial/adhesives/html/fundamentals.jhtml)

> [@](#):
>
> ```
> Surface Energies:  
> 
> ```
> 
> Adhesion is the molecular attraction between unlike materials, similar to magnetic force. Strength of attraction is determined by the surface energy of the material. The higher the surface energy, the greater the attraction. The lower the surface energy, the weaker the attractive forces. On a high surface energy material the adhesive can flow or “wet out” to assure a stronger bond.
> 
> On an automobile unwaxed for years, water spreads on the surface in large puddles. This is high surface energy allowing the water to flow. In comparison, on a freshly waxed car, the water will bead up. This is low surface energy; the liquid (or adhesive) does not flow out.

etc etc and more etc

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**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\
**Post date:** [May 4, 2002, 2:43pm UTC](https://boards.straightdope.com/t/what-substance-makes-tape-so-sticky/107183/3 "2002-05-04T14:43:09Z")

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Sticky stuff on post-it notes, tapes etc are low Tg, uncross-linked polymers . Low Tg (glass transition temperature) means they are soft and want to flow. Cross-linked low Tg polymers cannot flow but are still soft, thus they make good rubbers. Because they are polymers (semi liquid) they dont dry out as they have no solvent. I think post-it notes are made of polymers such as poly(butyl acrylate) if that helps