Can I Seal My Parcel with Milk?

Can I Seal My Parcel with Milk?

Sometimes Adhesive Grows on Trees: Natural rubber and its properties are very special – so it is often used for adhesives.

Everyone probably knows natural rubber. 70 percent of all car tires have natural rubber. It is also in condoms, gloves and air balloons. As well as in masking, packaging and other kinds of adhesive tape. That is because bonding with natural rubber really works. And really well, too.

The Advantages of Natural Rubber

Latex milk is directly gained from the rubber tree

You may wonder at first that you can even use natural rubber as glue. As a pure natural product extracted from the milk (latex) of the rubber tree (Hevea brasiliensis), this possibility exists. And although latex does not glue on the whole, it has very unique qualities: its special chemical structure gives it outstanding components for adhesives.

The reason: natural rubber consists in particular of long polymer chains. If it is mixed with resin (to make it sticky), you get an adhesive that is extremely flexible due to the length and mobility of these polymer chains. Adhesive tapes with natural rubber profit from these natural rubber properties: the adhesive remains mobile at low temperatures where other substances would become solid and brittle. And the entangling of the polymer chains produces a high inner solidity for the adhesive mass.

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Natural rubber adhesives - from tree to tape: 1) On a rubber plantation, the sticky substance is collected in small Cups, 2) It is then processed quickly so that it does not spoil, 3) Further processing, 3) Purchasing: The tesa group of companies orders full containers of rubber, 4) Shredders chop the rubber into granulated form, adding talcum powder as a separator, 5) Then the rubber starts to go its separate ways through the adhesive mass production, depending on the specific intended application, 6) The natural rubber adhesive is coated onto tape backings, rolled up, 7) cut to size and finally 8) shipped to our customers.

Natural Rubber Applications

Natural rubber consists of extremely long polymere chains that are entangled, not connected

The type of rubber used, the compounded resins, and other ingredients determine the performance of the natural rubber adhesive. In general, natural rubber properties offer many advantages for adhesive tape applications. The first of these is its outstanding peel adhesion or “grab” – not only on polar surfaces but also even on substrates with low surface tension ("non-polar substrates").

Cloth tapes are often based on natural rubber adhesives and used for thousands of applications, for example in the Entertainment Industry.

Peel adhesion is defined as the force needed to “peel” an adhesive tape from any given surface, whether flexible, smooth, or rigid. The attachment time required until it achieves its final tack is very short (low dwell time). Furthermore, adhesive tape with natural rubber adhesion can be removed easily and does not leave any trace, for example in the case of masking tape.

Finally there is the high tack, i.e. stickiness, of the adhesive: the adhesive tape glues with minimal pressure and minimal contact time. The rubber tree's latex makes the adhesive tape "faster." That explains why natural rubber adhesive tape and adhesives are often used and popular, and why they are found in and for a large number of applications – from cloth tape to packaging tape. And that is why in many adhesive tapes that safely seal our packages, there is milk from the rubber tree.

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Natural Rubber Disadvantages

The special chemical structure also entails some disadvantages, however: the adhesive in natural rubber glue or adhesive tape has a limited amount of adhesion and cohesion at temperatures above 70° C, requires stabilizers to resist aging and the environment in the event of UV and ozone exposure, and is not very resistant to chemicals and solvents.

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