Shutter Plywood Two-Step Phenolic Impregnation Line

Two-step phenolic impregnation line for shutter plywood production, used to produce phenolic impregnated and coated low-basis-weight kraft paper for concrete formwork panels.

Nantong Tongbo Machinery specializes in the manufacturing of two-step phenolic impregnation lines for shutter plywood (film-faced plywood) used in concrete formwork applications.

In shutter plywood production, phenolic overlay refers to phenolic impregnated and coated kraft paper rather than plastic film, typically using lightweight, low-basis-weight kraft paper to achieve flexibility and surface conformity.

Due to the thin structure of the kraft paper, a single impregnation process would result in most phenolic resin penetrating into the paper body, with limited resin remaining on the surface.

For this reason, the two-step process is realized through two independent process sections: the first section performs kraft paper impregnation followed by drying and cooling, while the second section carries out secondary phenolic resin coating, also followed by drying and cooling.

This separated process structure allows independent control of internal resin penetration and surface resin build-up.

This system is used to produce phenolic impregnated and coated kraft paper for film-faced plywood used as construction shuttering panels, ensuring stable surface durability, reliable concrete release performance, and consistent behavior during plywood hot pressing.

Process Configuration

1. Automatic splicing unwinder
2. Primary impregnation unit
3. Primary drying oven
4. Primary cooling unit
5. Secondary coating unit
6. Secondary drying oven
7. Secondary cooling unit
8. Web guide
9. Traction unit
10. Paper cutter
11. Conveyor
12. Stacker