Company Profile
Weifang Phoenix New Material Co., Ltd
Weifang Phoenix New Material Co., Ltd is a high-tech chemical enterprise integrating research and development,
production, sales and technical services. Headquartered in Weifang, Shandong Province. Its production facilities are
ocated in Weifang Binhai Chemical Industry Park, a state-approved chemical industry park.
Our mission is to be the leading sustainable "one-stop shop" chemical solutions company, providing customers
with innovative, science-led, differentiated products and solutions. To this end, we provide a safe and healthy working
environment for our employees and comply with all local, national and international regulations.
Product Parameters
| Parameter |
SG3 |
SG5 |
SG7 |
SG8 |
| Vloatile content incl.water (%≤) |
0.3 |
0.4 |
0.4 |
0.4 |
| Apparent density (≥) |
0.42 |
0.48 |
0.48 |
0.5 |
| Number of Fish Eye 1400cm2 (≤) |
20 |
20 |
30 |
30 |
| Plasticizer absorption of 100g resin(≥) |
26 |
19 |
12 |
22 |
| VCM Residue PPM (≤) |
5 |
5 |
5 |
5 |
| K-Value |
72-71 |
66-68 |
62-60 |
59-55 |
| Polymerizing Index |
1300+/-50 |
1000+/-50 |
800+/-50 |
700+/-50 |
Number of impurty particl
(≤) |
16 |
16 |
20 |
20 |
| Whiteness(160ºC after 10 min)(%≥) |
78 |
78 |
75 |
75 |
PVC is an amorphous white powder with a low degree of branching. Its glass transition temperature is 77~90ºC and it starts to decompose at around 170ºC . It has poor stability to light and heat. It will decompose at temperatures above 100ºC or after long-term exposure to sunlight to produce hydrogen chloride, and further autocatalytic decomposition will cause discoloration. Its physical and mechanical properties will also decrease rapidly. In practical applications, stabilizers must be added to improve its stability to heat and light.
The molecular weight of industrially produced PVC is generally in the range of 50,000 to 110,000. It has a large polydispersity. The molecular weight increases with the decrease of polymerization temperature. It has no fixed melting point. It starts to soften at 80~85ºC, becomes viscoelastic at 130ºC, and starts to change to viscous flow at 160~180ºC. It has good mechanical properties, with a tensile strength of about 60MPa and an impact strength of 5~10kJ/m3. It has excellent dielectric properties. PVC is insoluble in common solvents, but it will swell in monomers and certain chlorinated hydrocarbon solvents.
According to different application scopes, PVC can be divided into: general-purpose PVC resin, high-polymerization PVC resin, and cross-linked PVC resin. General-purpose PVC resin is formed by polymerization of vinyl chloride monomer under the action of an initiator; high-polymerization PVC resin refers to a resin formed by adding a chain extender to the polymerization system of vinyl chloride monomer; cross-linked PVC resin is a resin formed by adding a cross-linking agent containing diene and polyene to the polymerization system of vinyl chloride monomer.
According to the method of obtaining vinyl chloride monomer, it can be divided into calcium carbide method, ethylene method and imported (EDC, VCM) monomer method (it is customary to refer to ethylene method and imported monomer method as ethylene method).
According to the polymerization method, polyvinyl chloride can be divided into four categories: suspension polyvinyl chloride, emulsion polyvinyl chloride, bulk polyvinyl chloride, and solution polyvinyl chloride. Suspension polyvinyl chloride is the largest variety, accounting for about 80% of the total PVC production. Suspension polyvinyl chloride is divided into six models according to absolute viscosity: XS-1, XS-2...XS-6; XJ-1, XJ-2..., XJ-6. The meaning of each letter in the model: X-suspension method; S-loose type; J-compact type.
According to the amount of plasticizer content, PVC plastics are often divided into: non-plasticized PVC, plasticizer content is 0; hard PVC, plasticizer content is less than 10%; semi-rigid PVC, plasticizer content is 10-30%; soft PVC, plasticizer content is 30-70%; polyvinyl chloride paste plastic, plasticizer content is more than 80%. The difference in properties between hard PVC and soft PVC is shown in the table
PVC is prepared by free radical addition polymerization. The polymerization methods are mainly divided into suspension polymerization, emulsion polymerization, bulk polymerization and micro-suspension polymerization. Suspension polymerization is the main method, accounting for about 80%-82% of the total PVC output, followed by emulsion polymerization, accounting for about 10%-12% of the total PVC output, and then bulk polymerization, accounting for about 8%. The particle structure obtained by the suspension method and the bulk method is similar, with an average particle size of 100~160 microns. The particle size obtained by the emulsion method and the micro-suspension method is about 0.2 microns and 1 micron. Only a small amount of polyethylene copolymers for coatings are prepared by the solution method. Pure water, liquefied VCM monomer, and dispersant are added to the reactor, and then the initiator and other additives are added. After heating to a certain temperature, the VCM monomer undergoes a free radical polymerization reaction to generate PVC particles. Continuous stirring makes the particle size uniform and the generated particles suspended in water. In addition, there is also a micro-suspension method to produce PVC paste resin, and the product performance and paste-forming properties are good.
Suspension polymerization: The basic formula of vinyl chloride suspension polymerization consists of vinyl chloride monomer, water, oil-soluble initiator, and dispersant, but in fact, pH regulator, molecular weight regulator (mainly for low polymerization degree varieties), anti-sticking kettle agent, defoaming agent, etc. are also added. According to the different requirements of loose and compact polyvinyl chloride, the ratio of water to monomer in the formula varies between (1.2~2):1. The process of vinyl chloride suspension polymerization is roughly as follows: water, dispersant, other additives, and initiator are added to the polymerization kettle in sequence, vacuum and nitrogen are filled to remove oxygen, and then monomer is added, and the temperature is raised to the predetermined temperature for polymerization. During the polymerization process, the temperature and pressure remain constant. At the end of the period, the pressure drops by 0.1~0.2MPa, which is equivalent to 80%~85% conversion rate, and the polymerization is terminated. If the pressure is reduced too much, the resin will become dense. After the polymerization is completed, the monomer is recovered, the material is discharged, and the finished polyvinyl chloride resin is obtained through post-processing.
When vinyl chloride is polymerized, transfer to monomer is the main chain termination mode, so that the degree of polymerization of polyvinyl chloride (600~1600) is independent of the initiator concentration and is only controlled by temperature (45~65ºC, and the temperature fluctuation needs to be controlled within 0.2~0.5ºC. The polymerization rate is mainly regulated by the amount of initiator. At present, the heat transfer performance of the polymerization kettle is good, and a high-activity initiator such as peroxycarbonate is mostly used, with an amount of 0.02%~0.05%.
If high-activity and low-activity initiators are used in combination and the combination is proper, such as a half-life of 2h, it is expected to be close to a uniform reaction.
Uniform reaction is conducive to heat transfer and temperature control. Polyvinyl chloride-vinyl chloride is a partially miscible system, forming two phases: One phase is a polyvinyl chloride rich phase swollen with vinyl chloride (about 30%), which becomes the main site of polymerization. The other phase is a monomer phase dissolved with trace amounts of polyvinyl chloride (<0.1%), which is close to pure monomer. When the conversion rate is >70%, the monomer phase disappears, the system pressure begins to be lower than the saturated atmospheric pressure of pure vinyl chloride, and the vinyl chloride in the polyvinyl chloride rich phase continues to polymerize. The polymerization is terminated when the conversion rate reaches 85%, so as not to affect the loose structure of the resin particles.
The properties of the dispersant have a crucial effect on the morphology of polyvinyl chloride particles. When gelatin is selected, the surface tension of its aqueous solution is large (68 mN·m-1 at 25°C), and a compact resin will be formed.
When preparing loose polyvinyl chloride, the surface tension of the individual is required to be below 50 mN·m-1. Then partially hydrolyzed polyvinyl alcohol (surface tension of aqueous solution is 50~55 mN·m-1) and hydroxypropyl methylcellulose (surface tension of aqueous solution is 45~50 mN·m-1) is used in combination, and sometimes a third component is added. Although the preparation of composite dispersants can be partially referenced by surface tension, it still requires some experience and skills.
Product Description
Polyvinyl chloride (PVC) is the third largest synthetic polymer plastic in the world (after polyethylene and polypropylene), with an annual production of about 40 million tons of PVC. PVC is a polymer formed by the free radical polymerization mechanism of vinyl chloride monomer (VCM) in the presence of initiators such as peroxides and azo compounds or under the action of light or heat. Vinyl chloride homopolymers and vinyl chloride copolymers are collectively referred to as vinyl chloride resins.
PVC was once the world's largest general-purpose plastic with a wide range of applications. PVC is available in two types: rigid (sometimes abbreviated as RPVC) and soft. Rigid polyvinyl chloride is used for building pipes, doors and windows. It is also used to make plastic bottles, packaging, bank cards or membership cards. Adding plasticizers can make PVC softer and more flexible. It can be used for pipes, cable insulation, flooring, signs, phonograph records, inflatable products and rubber substitutes.
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