Seven Basic Requirements for Moulding and Extrusion of PVC Foaming Products

Extruder used for PVC low foaming products making can be either single-screw extruder or double-screw extruder. Proper extruder should be selected by manufacturer as per the specific requirements of PVC foaming products and real situation of manufacturers. After years of practice in PVC foaming products industry, some basic experience in PVC low foaming products making is concluded for reference.
　　

Requirements for extruder used for moulding and extrusion of PVC low foaming products are as below:-

(1) Power for extruder transmission system shall be sufficient and match the extrusion output;

(2) Slenderness ratio of extruder’s screw shall be high enough to establish stable extrusion

   pressure;

(3) The extruder must have enough melt pressure in case that foaming process occurs ahead of

   schedule;

(4) Extruder’s screw(s) should have high performance of mixing and plasticization to make sure  

   that PVC resin is well mixed and plasticized with all kinds of auxiliary agents.

(5) The extrusion system should have good performance of wearing and corrosion resistance;

(6) Precision of extruder’s temperature control system should be higher than that of ordinary

   extruders;

(7) The extruder should have stable transmission and fluctuation of speed should be smaller

   than ordinary extruders.

What is Rigid PVC Foaming Plastics?

PVC foaming plastics was first invented in the 1970s. And its industrial production was accomplished in the 1990s. Once it came into the market, it was called “future timber”. Its main ingredient is Polyvinyl Chloride (PVC). It can be used to perfectly replace timber due to its wide applications, thus giving it competition over timber.

  

Now much progress has been made in the processing technology of PVC foaming plastics. There are equipment, moulds, formula and workmanship available to PVC foaming plastics production.

Different filler like wood powder or Calcium Carbonate can be added into PVC foaming products. It will give PVC foaming products different properties by adding different fillers, which will contribute to replacing traditional a variety of construction materials and decoration materials. PVC foaming products are a kind of good material for surface decoration.

Compared with traditional wooden products, rigid PVC foaming products have performances of moisture, corrosion, insect resistance and flame retardancy. In addition, they are non-toxic and odourless. This kind of products will help save wooden products and improve people’s living conditions. They are ideal indoor and outdoor construction materials. PVC low-foamed materials can perfectly replace both traditional timber and some other construction materials. First it reduce the consumption of raw material, thus reducing the cost. And these products help lower the heat conductivity and promote the heat preservation, thus reducing thermal expansion.

Now PVC foaming products on the market mainly include rigid PVC free foaming plate, PVC skinning foamed solid plate, hollow grid plate, rigid PVC foaming profile and pipe for decoration and rigid PVC foam wood, etc. These products have wider and wider applications in the fields of engineering construction, packaging and furniture, etc.

Our colleagues attending Alibaba operation skill training class

Our colleagues, Ms. Grace and Ms. Carrie, attended A-class Alibaba Shop Operator Training Class held in Changshu Fangzheng Bole E-commerce Traing Center, August 17-18, 2016.

About two weeks ago, we received an invitation from staff working for Fangzheng Bole Business School. The skill training class began on the morning of August 17 and ended next afternoon. Professional Alibaba operation skill trainers were invited to give lectures on Alibaba E-shop operation, negotiation skills, SEO skills, etc. After the theoretical lessons, all trainees were divided into several groups to imitate real business situations to improve their negotiation skills. The training class was very interesting and useful. Our colleagues learned a lot from this training class and it will be an unforgettable experience. 

  

Classification of PVC Heat Stabilizer

PVC Heat stabilizer is a kind of chemical additive used for preventing or or reducing thermal decomposition or cross-link in polymer processing and extending the durability of polymers. In general, PVC heat Stabilizers can be classified into salt based, fatty-acid soap based, organic tin compounds and composite stabilizer.

1. Salt Based Stabilizer

Salt based stabilizer are those inorganic and organic acid lead salts combined with “base”. This type of stabilizer is characterized by excellent heat stability, weatherability, electric insulation relatively low cost, low transparency and some certain toxicity. The recommended dosage ranges from 0.5%~5.0%.

2. Fatty-acid Heat Stabilizer

This type of heat stabilizer is chemical compounds made up of fatty-acid radicals and metal ions, also called metallic soapstabilizer. Its properties are related to acid radicals and metal ions. Recommended dosage is 0.1%~3.0%.

3.  Organo-tin Heat Stabilizer

This type of stabilizer together may form a ligand with unstable chlorine atom in polyvinyl chloride. And carboxylic esterbase of organic tin in ligand won’t replace the unstable chlorine atom. This type of heat stabilizer is characterized by high heat stability, good transparency and heat resistance. The shortcoming of this type of stabilizer is relatively high cost.

4. Compound Heat Stabilizer

This type of heat stabilizer is chemical compound in liquid type based on salt based or metallic soap or solid type based on organic tin. Metal salt stabilizers include Ca-Mg-Zn, Ba-Ca-Zn, Ca-Zn, Ba-Zn and Ba-Cr stabilizer. Generally used organic acid include organic fatty acid,  naphthenic acid, oleic acid,  benzoic acid and  salicylic acid, etc.

5. Organic Compound Heat Stabilizer

Few of this type of heat stabilizer can be used as main stabilizer (mainly organic chemical compound containing nitrogen). In addition, it also includes some other polyols and phosphite ester with high melting points.

Polyethylene Wax (PE Wax)

Polyethylene Wax (PE Wax) is also called Macromolecular Wax. It is widely used thanks to its excellent cold resistance, heat resistant, chemical resistance and abrasion resistance. In normal processing, PE Wax is directly added as a kind of additive for processing of polyolefin. It will enhance the gloss and processability of products. As a kind of lubricant, it has stable chemical property and electric property. Polyethylene Wax (PE Wax) can be compatible with Polyethylene, Polypropylene, ethylene propylene rubber (EPR) and  butyl rubber well. It will help improve the fluidity of Polyethylene, Polypropylene and ABS and the demoulding property of  Polymethyl Methacrylate (PMMA) and Polycarbonate (PC). Compared with some other external lubricants, Polyethylene Wax (PE Wax) has better internal lubrication.

Application of Polyethylene Wax (PE Wax)

　　 

1. Color masterbatch and filled clusters: Polyethylene Wax (PE Wax) is used as dispersant in masterbatch processing like Polyolefin masterbatch. It has good compatibility with Polyethylene (PE), Polyvinyl Chloride (PVC) and Polypropylene (PP) and has excellent internal and external lubrication.

　　 

2. PVC pipe, PVC profile and Compound Stabilizer: Polyethylene Wax (PE Wax) is used as dispersant, lubricant and brightening agent in PVC profile, PVC pipe & fitting, Polyethylene (PE) and Polypropylene (PP) to strengthen the plasticization, toughness and surface smoothness. And it is also widely used in the production of PVC compound Stabilizer.

3. Printing ink: Polyethylene Wax (PE Wax) can be used as carrier of pigments thanks to its high light fastness and chemical resistance. It will help improve abrasion of paint and printing ink and enhance the dispersion of pigments and fillers.

　　 

4. Wax products: Polyethylene Wax (PE Wax) is widely used in production of car wax, polishing wax, candle and crayon, which will help improve melting point, strength and gloss of wax products.  

　　 

5. Cable and Wire: Polyethylene Wax (PE Wax) can be used as lubricant of cable insulation material. It will help strengthen the dispersion of fillers and increase the speed of extrusion.

　　 

6. Hot Melts: Polyethylene Wax (PE Wax) can be used as dispersant in hot melting emulsion, thermoset powder coatings, road mark paint and traffic paint.

Customers from Pakistan Visiting Our PVC Stabilizer Factory

Mr. Ali has a trading company specialized in plastic chemicals located at Karachi, Pakistan. Now he wants to find a stable supplier of PVC Heat Stabilizer. At 10:30am, my colleague Grace and I picked them up from the hotel. After about one-hour driving, we arrived at our PVC Heat Stabilizer factory. In the factory, we showed them every part of our factory, including PVC Heat Stabilizer production lines, PE Wax production lines, warehouse, logistic center, etc. During the visit, Mr. Ali was very eager to communicate with our technicians regarding many details. Mr. Ali said this visit left him very deep impression. And he decided to give us an order of 1x20GP of Lead Compound Stabilizer. We will have good cooperation on PVC additives in the future, I believe.

Main Factors Affecting the Transparency of PVC Products

Effect which PVC heat Stabilizer has on the transparency of PVC products is determined by main factors as below:-

1. Refractive Index of PVC Heat Stabilizer　

If PVC heat Stabilizer has the same or similar visible-light refractive index of 1.52~1.55 as PVC Resin, PVC finished products will have higher transparency, on the contrary, it will be lower.

2. Linear Length of PVC Heat Stabilizer Molecule ( Molecular Group )

If linear length of PVC Stabilizer molecule ( molecular group ) is smaller than that of  visible wavelengths 400~735nm, it will have less refraction to visible-light, thus having better transparency, on the contrary, it will be lower.

3. Compatibility of PVC Heat Stabilizer with PVC Resin
　　 

Compatibility means the mutual affinity between two blended materials. Good compatibility may result in molecule-level dispersion. PVC Heat Stabilizer has excellent compatibility with PVC Resin under melting condition, thus not causing two phase. Compared with solid metallic soap type heat stabilizer, liquid PVC Stabilizer has better compatibility and relatively smaller linear length, so PVC finished products will have a better transparency.

Liquid organo-tin Heat Stabilizer will make PVC finished products have the best transparency. While Ba-Zn, Ba-Cd and Ca-Zn Stabilizer have limited compatibility and relatively big linear length, it will affect the transparency of PVC finished products.
 

Di-basis Lead Phosphite and Tri-basic Lead Sulfate have bad compatibility with PVC Resin and big molecular group, so it is used to manufacture non-transparent products.

Customers from India Visiting Our Office

Customers from India, Mr. Raghav and his brother visited our office located at Xishan District, Wuxi City, Jiangsu Province, July 29, 2016.

Mr. Raghav has a trading company in New Delhi. Now their company is specialized in import trade of PVC Buckle Plate from Haining City, Zhejiang Province. Now they decide to establish a PVC Buckle Plate factory of their own. This Monday, Mr. Raghav and his brother came to China to purchase relevant PVC extrusion machinery for their PVC Buckle Plate making. Then they came to our office for relevant ingredients used for manufacturing PVC Buckle Plate. We made detailed introduction of all materials and our company. The talk lasted for about one hour. Mr. Raghav said this visit left him a very good impression. They would purchase all relevant materials used to produce PVC Buckle Plate from us once their machinery is ready.