Polycarbonate, solvent cementing

Polycarbonate Solvent cementing is the most common method of bonding polycarbonate. Bonding can be carried out with specific solvents, mixtures of solvents, and mixtures of polycarbonate and solvents. Methylene chloride, when used by itself, has an extremely fast evaporation rate and is recommended for fast assembly of polycarbonate parts. A solution of 1-5% polycarbonate resin in methylene chloride has a decreased evaporation rate. Parts bonded with methylene chloride are usable at elevated temperatures after approximately 48 hours, depending on the bonding area. Ethylene dichloride is also used (5). 

Most thermoplastic foams can be solvent cemented. However, some solvent cements will collapse thermoplastic foams. The best way to determine if such a problem exists is to try it. In cases where the foam collapses due to softening of the foam cell walls it is desirable to use water-based adhesives based on SBR or polyvinyl acetate, or 100%-solids adhesives. In general, the relatively amorphous thermoplastics, such as the cellulosics, polycarbonate, and polystyrene are easier to solvent cement than the crystalline materials, but there are exceptions. 

Solvent cementing of parts of polycarbonate may be effected by the use of a variety of solvents or light solutions of polycarbonate in solvents. Methylene chloride, a 1-5% solution of polycarbonate in methylene chloride, and a mixture of methylene chloride and ethylene dichloride (with a maximum of 40% ethylene dichloride) are commonly recommended. 

Solvent cementing is the most common method of bonding polycarbonate. It can be carried out with specific solvents (Table 9.6), mixtures of solvents, and mixtures of polycarbonate and solvents. 

Methylene chloride is a very fast solvent cement for polycarbonate. This solvent is recommended only for temperature chmate zones and on small areas. A mixture of 60 percent methylene chloride and 40 percent ethylene chloride is slower drying and the most common solvent cement used. Ethylene chloride is recommended in very hot climates. These solvents can be bodied with 1 to 5 percent polycarbonate resin where gap filling properties are important. A pressure of 200 psi is recommended. 

Methylene chloride is a very fast solvent cement for polycarbonate. This solvent is recommended only for temperature cUmate zones and on small areas. A mixture of 60 percent... 

The most common means of joining some plastics is to employ what has been called a plastic dope or plastic cement. The type will vary depending on the plastic adherend to be joined, since the best choice of plastic dope for that adherend will be a solvent blend of that adherend. PVC, ABS, polystyrene, and polycarbonate, for example, form durable bonded joints through the use of solvent adhesives made by blending suitable solvents with solid plastic of the same composition as the adherend to be joined. After the solvent dissipates from the bondline, the joint is virtually continuous plastic across the interface. This is often referred to as a welded plastic joint. 

---