No : PCP 005

Non Silicone Release Coating

A coating applied to the backing , on the
side opposite to the adhesive coated...
1.
2.
3.
4.

A barrier to mechanical interlocking
Prevention of inter diffusion
Poor adsorption and surface reaction
Low s...
An important factor in choosing an
abhesive is temperature dependence.

A material could act as an abhesive at
room temper...
No : PCP 005

Date : 30 JAN 2014

minimal, and the surface has the
properties of a good abherend.
Wetting can be determine...
Secondly , all most all Silicone coatings
are thermally cured at processing
temperature above 90 deg C.
Most importantly ,...
No : PCP 005

unwanted wrinkle formation and
wastage.

Date : 30 JAN 2014

biocides, solvents, etc., incorporated into
the...
Liner less Labels

Heat Transfer Labels.

7

Self wound Film tapes based on PET ,
PP, PVC Tapes , Fabric tapes, Foil tapes...
No : PCP 005

Date : 30 JAN 2014

Just to sum up
The Non Silicone Release coating
should be

Page

8

1. Quick drying.
2. ...
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Non silicone release coating

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Non Silicone Release Coating
A coating applied to the backing , on the side opposite to the adhesive coated that provides ease of unwind and prevents de laminating or tearing. Without a release coating, the tape would adhere to its own back and would not unwind.

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Non silicone release coating

  1. 1. No : PCP 005 Non Silicone Release Coating A coating applied to the backing , on the side opposite to the adhesive coated that provides ease of unwind and prevents delaminating or tearing. Without a release coating, the tape would adhere to its own back and would not unwind. This coating is also , termed as Abhesive. The coated abhesive , creates a surface that discourages adhesion. Hence the release values ( or the adhesion to self ) , is suitably controlled. Date : 30 JAN 2014 In order to understand how abhesives work, Let us understand the mechanism of adhesion and the factors that affect it. Adhesion occurs through a: mechanical interlocking, interdiffusion, adsorption (surface reaction), and electrostatic attraction. adhesion depends on the surface topology, surface tension and energy, wetting, and thermodynamic work of adhesion. The applications for abhesives are nearly as numerous and as commercially important as they are for adhesives. Therefore, surface treatment is required to enhance adhesion. This is done by Page However, the main purpose of this review will be to explain the material and surface science fundamentals required for an abhesive to function. 1 A variety of materials and processes have been developed to provide surfaces that function as abhesives.
  2. 2. 1. 2. 3. 4. A barrier to mechanical interlocking Prevention of inter diffusion Poor adsorption and surface reaction Low surface tension and thermodynamic work of separation 5. Limited or no electrostatic attraction 6. Incorporation of a weak boundary layer. Since many of the factors causing adhesion are of a chemical nature, a good abhesive must also be chemically inert toward the two materials whose adhesion are to be prevented. Abhesion, therefore, occurs via one of two primary modes: (1) prevention of adhesion to the abhesive coating layer, or (2) an easily separable coating or cohesively weak boundary layer. Thus, there are several ways in which abhesives can be classified. The most popular classifications are permanent (corresponding to 1 above) and sacrificial (corresponding to 2 above). Several examples of each are readily evident in the household environment. The coating on a non-stick baking pan is an example of permanent abherend. 2  removing weak boundary layers,  changing surface topography,  changing the chemical nature of the surfaces, and  modifying the physical structure of the surface. Abhesion or Release Coating requires just the opposite. For maximum abhesion, or resistance to adhesion, the surface should exhibit the following characteristics. Date : 30 JAN 2014 Page No : PCP 005
  3. 3. An important factor in choosing an abhesive is temperature dependence. A material could act as an abhesive at room temperature and as an adhesive at elevated temperatures. Thermoplastic polyethylene coatings are good examples of this. Polyethylene is relatively inert with a low surface energy, non-stick surface in its solid state, but it has good adhesive properties in the molten state. Another factor to be considered in choosing an abhesive is volatility. Water would be a good abhesive, but because it vaporizes at relatively low temperatures, water could not be used as a mold release in many high temperature applications. Theory Two solid materials generally do not adhere to each other because wetting does not take place and there is no penetration or interdiffusion of one material into the other. When wetting is minimal, the secondary van der Walls bond forces that provide the majority of molecular adhesion are not large, the work of adhesion is 3 Flour, grease, or oil used for non-stick baking are examples of sacrificial abherends. Permanent abherends require that the abhesive material have good spreading tendency on the material to be protected and a surface that exhibits poor spreading tendency to the material which adhesion is to be prevented. The permanent abherend must be a good coating material (i.e., easily applied, uniformly spread over the surface to be protected, and relatively permanent during all expected processes). Sacrificial abherends require only that the abhesive material fill the pores or smooth-out the roughness of a surface (e.g., an inert powder on a rough metal surface). Sacrificial abherends generally remain attached to both surfaces after release, and they must be applied to a surface every time it is to be protected. On the other hand, permanent abherends will last through many cycles of release. Date : 30 JAN 2014 Page No : PCP 005
  4. 4. No : PCP 005 Date : 30 JAN 2014 minimal, and the surface has the properties of a good abherend. Wetting can be determined by contact angle measurements Types of Abherend materials There are many materials that can be used as abhesives. These are generally classified chemically as shown in Table 1. They can be supplied in many different forms such as fluids, waxes, greases, emulsions, dry films, and solid powders. Many commercial abhesives are of proprietary composition. These products can be formulations of more than one type of abhesive with modifiers or additives, such as emulsifiers, biocides, solvents, etc., incorporated into the final product. Silicone based release coatings are meant for , very easy release , or the release values as low as , 0 to say 70 grams/25 mm width. In other words a 4 Let us now compare the Release properties of Silicone based Coating and Non Silicone based. Page All abhesive materials are characterized by providing a low energy surface, and any liquid placed on such a surface will exhibit a contact angle, which will be larger as - increases. When is large enough, such poor adhesion will occur that the application of a modest external stress will cause the bond to separate. Table 2 gives values of for common abhesive materials.
  5. 5. Secondly , all most all Silicone coatings are thermally cured at processing temperature above 90 deg C. Most importantly , it is really impossible to coat and cure silicone coatings inline with adhesive coating. The only exception to this could be UV cured silicones , which cured at room temperature. However this option is relatively ruled out owing to the cost of manufacture. They are very expensive. Now on the other hand , Non silicone coatings are meant for controlled release with release values of 50 grams to 200 grams depending upon the requirement , as well as the backing substrate. This is an added advantage while processing further to adhesive coating. Non silicones generally do not require any Thermal curing , and hence can be coated at lower temperatures. These coatings are therefore coat able inline with adhesive coating. This does not mean that non Silicone coatings is a answer to all self wound tapes. While choosing a most suitable release coat , one has to take into consideration , The peel strength values of the product , as well as the Tensile strength and percentage of elongation of the substrate. The unwind force or the adhesion to self values should be lower than the tensile strength values for a particular substrate. This is true in particular , when we consider films like Poly ethylene , PVC , Poly propylene or various paper as backing substrate. The unwind force higher than the tensile strength , could result into elongation of films like PE, PVc , PP , and snapping of paper based tapes. The elongation of films will cause 5 Silicone release coated film or paper will provide a too easy release while unwinding a self wound Adhesive tape. Many a times this could be a unwanted property , considering the further conversion or application methods. Date : 30 JAN 2014 Page No : PCP 005
  6. 6. No : PCP 005 unwanted wrinkle formation and wastage. Date : 30 JAN 2014 biocides, solvents, etc., incorporated into the final product. Applications of Non Silicone Release Coating. 6 There are many materials that can be used as abhesives. These are generally classified chemically as shown in Table 1. They can be supplied in many different forms such as fluids, waxes, greases, emulsions, dry films, and solid powders. Many commercial abhesives are of proprietary composition. These products can be formulations of more than one type of abhesive with modifiers or additives, such as emulsifiers, Surface protection tapes, based on PE Film , paper Page Types of Non Silicone Release Coatings
  7. 7. Liner less Labels Heat Transfer Labels. 7 Self wound Film tapes based on PET , PP, PVC Tapes , Fabric tapes, Foil tapes Date : 30 JAN 2014 Page No : PCP 005
  8. 8. No : PCP 005 Date : 30 JAN 2014 Just to sum up The Non Silicone Release coating should be Page 8 1. Quick drying. 2. Non curing type , no chemical reaction or Cross linking is involved. 3. very low coat weight 4. Should not interfere with the PS Adhesive , or lower the peel adhesion , due to unwanted pick up of the release coating by adhesive 5. cost effective 6. Able to coat in line , along with adhesive.

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