1.1 Preface

Polyvinyl chloride plastic is a widely used plastic material. Especially rigid PVC plastics have great advantages in construction materials. Such as PVC wood-plastic foam materials, new chemical building materials with plastic instead of wood. Because of the fine cell structure inside, it is similar to natural wood, anti-corrosion, flame-retardant, and can be processed by woodworking machinery, which is convenient and special. After vigorously promoting calcium and zinc environmental stabilizers, the pollution of metal lead has been eliminated. Unlike wood products, there is formaldehyde pollution. It can achieve zero formaldehyde. The newly developed integral decorative wall panels can be installed quickly and save a lot of auxiliary materials, manpower and time.
Waterproof, anti-corrosion, flame retardant, zero formaldehyde, fast installation is an ideal green environmental protection building decoration material, and it can also be said to be a revolution in building decoration.

1.2 Technical status

Production Technology of PVC Wood Plastic Foamed Wallboard
It belongs to the technical range of rigid PVC low foaming technology, which is mainly composed of PVC resin, processing aids, cell regulators, foaming agents, wood powder, fillers, stabilizers, lubricants, pigments, etc.
The typical formula is as follows
1.2.1 Typical formula of rigid PVC skin foaming
PVC resin (SG5-SG7 type) 100 PHR
Processing aid 2 PHR
Foaming regulator 4-10 PHR
Foaming agent 1-2 PHR
Wood flour 20-40 PHR
Filler 20-60 PHR
Environmentally friendly calcium zinc stabilizer 4-5 PHR
Lubricant 1-2 PHR

1.2.2 Production process

PVC resin + additives → high speed mixing → low speed mixing → conical twin-screw extrusion → coat hanger die forming → cooling and shaping → rubber roller traction → cutting products → inspection and installation.

1.2.3 Rigid PVC foaming process parameters

The molding process of rigid PVC foam products is divided into self-foaming, skinning foaming and other processes. It is a chemical foaming process. The principle is to use temperature to decompose the foaming agent into gas during the PVC plasticization process. In the PVC plasticized melt, after the die is extruded, the melt temperature and pressure drop, and the gas dissolved in the PVC melt is supersaturated and phase separated under the critical system to form a large number of cells and foam, and the bubbles on the surface are cooling The sizing mold is fixed without expansion under the action of rapid cooling, forming a dense and smooth crust layer on the surface, thereby producing crust foamed PVC products.

1.2.4 Defects

The production of rigid PVC foaming materials has a wide range of raw materials, complex components and high requirements for process parameters. Objectively, it increases the difficulty of production quality control. Subjectively, copying the parameters and characteristics of PVC lead salt materials, and rigidly copying them, brings technical misunderstandings. The yield is low and the quality is difficult to control, especially the high cost of foaming processing aids and foaming regulators.

2.1 The solution of Zhihai stabilizer

In response to the problems of rigid PVC foam materials, Shenzhen Zhihai's R&D team adopted new patents, new processing ideas, carried out trials and made new progress.
Examples are as follows:
Case 1 Rigid PVC foam wood plastic foam wallboard:
Traditional formula Zhihai AIM-FOAM new formula
PVC resin powder 100 PHR 100 PHR
Filler 50 50
Wood flour fiber 35 35
Foaming agent 1.5 0
Processing aid 2 0
Foaming regulator 4 0
Environmental protection calcium zinc stabilizer 4.5 0
AIM-FOAM functional additives 0 9 (model 5148-A)
Lubricant 1.2 1.2
Total 198.2 195.2

Case 2 Rigid PVC foam template:
Traditional formula Zhihai AIM-FOAM new formula
PVC resin powder 100 PHR 100 PHR
Filler 27 27
Bamboo wood powder 27 27
CPE anti-impact agent 4 4
Foaming agent 3 0
Processing aid 2 0
Foaming regulator 10 0
Stabilizer 4.5 0
AIM-FOA functional additives 0 13.5 (model 5146-B)
Epoxidized soybean oil 2 2
Total 179.5 173.5

Our Zhihai R&D team adopts a new patented technology, Zhihai AIM-FOAM technology, combined with a packaged mixing process, to form multifunctional additives 5148-A, 5148-B. Experiments show that AIM-FOAM multifunctional additives , It can make the rigid PVC foam material, the formula is simplified, the cost is reduced, the performance and quality are improved, the process control of the production process is more stable, the cells are dense and uniform, and the surface of the product is smooth and clean. It is worth further experimentation and promotion.