Continuous lamination

Phenolic resins Good acid resistance, good electrical properties (except arc resistance), high heat resistance Compression molding, continuous lamination... 

When describing in more detail the characteristics and methods of manufacture of laminated sheet materials of different types it is helpful to use the classifications below, each of which is covered by a British Standard High-pressure laminates Decorative continuous laminates Direct-faced boards Composite boards. 

The British Standard for decorative continuous laminate ( DCL ) is BS 7332 1990,3 which gives the following definition ... 

Figure 60 Continuous laminating press (Photo Grecon)...

Continuous laminates are manufactured also using polyester resins in place of melamine however, such laminates are less durable and best suited to light duties such as shelving, vertical surfaces, and edging. 

For applications such as cladding fire-rated bulkheads and doors in ships and other vessels decor papers have been bonded directly to thin steel sheet. However, for these purposes steel coated with PVC and thin continuous laminate bonded to steel now are used more commonly. 

A European Standard for Continuous Laminate is being developed within CEN Technical Committee 249 but at the time of writing there have been no proposals to harmonize standards for Direct-faced or Composite Boards. 

BS 7332 1990 Decorative continuous laminates (DCL) based on thermosetting resins. 

Polystyrene Low cosi. moderate heat distortion, good dimensional stability, good stiffness, impact strength Injection molding Continuous laminating... 

Acrylics Good gloss, weaiher resistance, optical clarity, and color excellent electrical properties injection molding Vacuum forming Compression molding Continuous laminating... 

Vinyls Excellent wealherability, superior electrical properties, excellent moisture and chemical resistance, self-extinguishing injection molding Continuous laminating Rotational molding... 

Figure 35. Free rise, continuous lamination process (72).

Hanak et al (9) presented a paper regarding the use of propoxylated Mannich adducts for the production of continuous laminates and fiberglass-reinforced molded rigid foam characterized by CFC reduction or elimination. Table 46 shows an example of the formulation and process conditions employed (9). 

Moss and Skinner of Jim Walter Research Corp. (41) discussed a basic formulation study for production of continuous lamination of urethane-isocyanurate foams. 

Foaming Process of Resol-Type Foam. The foaming processes for phenolic foam of both the resol type and benzylic-ether type are the same as those for rigid polyurethane foams. The block-foaming process (slab foaming), pouring process, continuous-laminate process, and spray process are used. See Figure 57. 

Continuous-Laminate Process. This process is to foam continuously between two sheets of facing material, employing a laminator (double-belt conveyor). The productivity of this process is the highest, i.e., the yield of raw material is very good, and a high-quality product can be produced. The selection of material, foaming machine and laminator design are very important factors in this process. Excellent quality products have been manufactured by this process in the United States, Western Europe, and Japan. 

Figure 60. Continuous laminator for phenolic foam board (11). (Courtesy of Toho Madiineiy Co.)...

---