Tetra Etch

Sodium naphthalene etching or Tetra Etch for PTFE improves the surface roughness and creates unsaturated bonds, carbonyl and carboxyl groups. 

Sodium napthalene solutions in tetrahydrofuran solvent have been used to provide surface treatment of fluorocarbon surfaces for several decades. A commercial surface treatment based on this process has been Tetra-Etch.63 Recently the manufacturers of Tetra-Etch introduced Fluoro-Etch, which has several advantages. Fluoro-Etch requires no refrigeration, is easier to handle, and offers significant cost, efficiency, and safety advantages. It offers a 1-year shelf life and is manufactured in both the United States and Europe. 

Tetra-Etch and Fluoro-Etch, Action Technologies, Inc., Pittston, PA. 

Table 7.2 shows the effect of sodium etching on several fluoropolymers by Tetra-Etch on the surface composition and lap shear bond strength. In general, the data for various fluoropolymers indicate an increase in the adhesive bond strength with increasing fluorine and chlorine content. Kinetics of treatment is more favorable to perfluorinated PTFE than PVF that contains one fluorine per monomer unit according to the data in Table 7.2. 

Etching solutions can be purchased from a number of sources. They include Fluoro Etch by Acton Corp. and Tetra-Etch by W. L. Gore Associates. Some companies, such as Acton Corp., provide surface treatment service. Operational safety and waste disposal are two issues concerning parties that deal with etching solutions. 

Source of data Gasonics/IPC Applications Notes, Gasonics International, San Jose, California. Tetra-Etch by WL Gore Associates, Inc. Too low to measure. 

Teflon and other fluorocarbon surfaces may be altered by chemical treatments using solvent solutions of sodium naphthalene complex or molten sodium. Teflon etchants, for example, Tetra-Etch , a tradename and product of W. L. Gore Associates, are effective in improving adhesion to Teflon. Oxidation treatments for metals such as copper or aluminum also produce highly polar oxide surfaces that are more easily bondable. The reader is referred to several sources for a more comprehensive... 

TETRA-etch A nonpyrophoric (will not ignite when exposed to moisture) proprietary etchant. 

Commercial solutions of etchant do not contain ammonia or tetrahydrofuran for safety and health reasons. For example, Tetra-Etch contains 25% by weight of sodium-naphthalene complex and 75% of ethylene glycol dimethyl ether. Fluoro Etch (offered by Acton Technologies, Inc., Pittston, PA) contains about 30% sodium-naphthalene complex and 70% of an ethylene glycol solvent. Acton Technologies has reported successful use of both ethylene glycol dimethyl ether and diethylene glycol dimethyl ether as solvents.OO... 

Gore-Tex W.L. Gore Assoc. Tetra-etch W.L. Gore Assoc. 

To show surface compositions and SLS joint strength of PTFE and PVF polymers following Tetra-Etch treatment for various times (Brewis et al. 1995)... 

N, but in this case, there was relatively little surface modification observed by XPS. This result was attributed to the removal of a potential weak boundary layer by the Tetra-Etch treatment. 

Table 5.23 shows the effect of sodium etching for several fluoroplastics by Tetra-Etch (www.gore. com), on the surface composition and lap-shear... 

Table 5.23 Effect of Sodium Etching (Tetra-Etch by W. L. Cole) on the Surface Composition and Adhesion Bond Strength of Fluoropolymers ...

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