Surface preparation plastisols

Plastisols are used in automotive assembly for lower performance applications, e.g. the bonding of panel reinforcements. An advantage here is that they are capable of bonding oily surfaces some absorb the oil film during cure, reducing the required surface preparation. Also, the adhesive may be formulated such that it cures during the paint-stoving process. 

The double shell method of roof constmction uses only about half as many metal stampings as the traditional welded assembly and gives a rigid, vibration-free product. The plastisol is effective because it requires minimal surface preparation and because bond line thickness is not critical. 

Poly(vinyl chloride) is used in industry on a very large scale in many applications, such as rigid plastics, plastisols, and surface coatings. The monomer, vinyl chloride, can be prepared from acetylene ... 

Quite contrary to popular belief - a belief founded on the use of traditional adhesives - reliable joints can be obtained from unprepared surfaces. Of course, there is no denying that the better the preparation the better the overall performance. But, providing contamination is not gross, perfectly adequate levels of performance can normally be obtained from Anaerobic Cyanoacrylate Plastisol Toughened acrylic and Toughened, heat-cured, epoxide-based adhesives. 

Commercial PVC is generally produced by addition polymerization. It may be produced by a variety of techniques such as suspension, emulsion, micro suspension and bulk. PVC, as normally prepared, is a white granular material, ranging in particle size from 5-400 microns and with apparent bulk densities of 0.5-0.8 g/cc. Emulsion type PVC is usually smaller in particle size. This type of PVC is also called dispersion type. Dispersion type PVC is grounded to further decrease particle size and this type of PVC is called paste type. Paste PVC particles are irregular in shape and have relatively high surface area. Both dispersion and paste type PVC are suitable for plastisol applications. 

In a typical operation, PVC powder compound is metered into a form that has been machined to a high finish to represent the desired part surface, then heated to a temp-eramre at which the compound will sinter and partly fuse, while sufficient rotation is applied to obtain a uniform coating of the inside of the form. The latter may be, in fact, the same form previously used to rotomold PVC plastisol. The polyurethane (PUR) component may be foamed within the form or, more often, prepared previously, placed in the form, and fusion of the PVC, with resultant high PUR adhesion, then completed. ... 

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