Production process and application of calcium carbide PVC

Introduction

Polyvinyl chloride (PVC) is one of the most widely used synthetic resins in the world today, and is widely used in the fields of construction, piping, packaging, adhesives, etc. There are two main production methods for PVC: ethylene and calcium carbide. The calcium carbide method is favored because of its wide source of raw materials and relatively simple process. In this paper, the production process, advantages and disadvantages, applications and future development trend of calcium carbide PVC will be discussed in detail.

First, calcium carbide PVC production process

Calcium carbide PVC production process mainly includes the following steps:

1. Raw material preparation: The main raw materials of calcium carbide PVC are calcium carbide (CaC₂) and chlorine (Cl₂). Calcium carbide can be produced by electrolysis of limestone, while chlorine is generally obtained by electrolysis of sodium chloride.

2. Chlorination: Chlorine gas is reacted with calcium carbide in a suitable reaction apparatus. The chemical equation for this reaction is:

CaC2​+2Cl2​→CaCl2​+C+CCl2

   The calcium chloride (CaCl₂), carbon (C) and dichloroethylene (CCl₂) produced in the reaction will continue to react to form polyvinyl chloride.

3. Polymerization reaction: Under controlled conditions, the resulting vinyl dichloride is polymerized to form PVC. this process usually uses a free radical polymerization reaction, and factors such as reaction temperature, pressure, and catalyst will have an effect on the effect of the polymerization.

4. Post-processing: After the polymerization reaction, the PVC resin needs to go through steps such as washing, drying and granulation to remove unreacted monomers and catalysts, and ultimately to obtain high purity PVC pellets.

Second, calcium carbide PVC application areas

The PVC formed in the production process of calcium carbide method PVC has good processing performance and relatively low cost, so it has been widely used in many fields:

1. Building materials: PVC pipes, doors, windows, floors and other building materials are important application areas of calcium carbide PVC. These products are widely used in construction projects due to their corrosion-resistant, lightweight and heat-insulating properties.

2. Packaging industry: PVC films and sheets are widely used in FMCG packaging and industrial packaging. Due to PVC's excellent transparency and moisture resistance, it helps protect products and extend shelf life.

3. Wire & Cable: PVC is widely used as an insulating layer for wire and cable, making cable products safer due to its good electrical insulation properties and fire resistance.

4. Medical Devices: PVC is also used in medical devices and disposable products (e.g., infusion tubes, blood bags, etc.) due to its good biocompatibility and processability for medical applications.

Third, the future development trend

With the enhancement of environmental protection awareness and the proposal of sustainable development goals, the production and application of calcium carbide PVC are facing new challenges and opportunities:

1. Improvement of environmental protection technology: In the future, the production process of calcium carbide PVC will develop in the direction of reducing waste emissions and improving the utilization rate of resource recycling. New catalysts and green reaction conditions will be researched and applied to reduce the negative impact on the environment.

2. Enhancement of product performance: Through modification technology, the thermal stability and UV resistance of calcium carbide PVC will be enhanced to realize a wider range of applications. This will promote its competitiveness in the high-end market.

3. Research on alternative raw materials: Research and development of new alternative raw materials, reduce dependence on calcium carbide, and gradually adopt more environmentally friendly materials will be another direction for the development of calcium carbide PVC in the future.

4. Policies and regulations to promote: The increasingly strict regulation of the plastics industry in various countries, policies and regulations will promote the production of enterprises must adopt more environmentally friendly processes and raw materials, in order to meet the requirements of sustainable development.

Conclusion

With its unique advantages and wide range of applications, calcium carbide PVC will continue to occupy an important position in the plastics industry in the future. Despite the challenges of environmental protection and safety, advances in modern technology will provide new impetus for its innovation and development. In the future, the research on the production process, product performance and environmental impact of calcium carbide PVC will inject new vitality to realize greening and sustainable development.