Application
Barium sulfate in plastic PVC - plays an extraordinary role
Behind the colorful and variously shaped PVC products, there are many unsung but crucial "supporting roles". Barium sulfate is one of them. It is not merely a simple filler; it is the key to enhancing the performance of PVC and reducing costs. Today, let's delve into the strict requirements of PVC plastic for barium sulfate and exactly how it empowers PVC products.
01. The "strict requirements" of PVC plastic for barium sulfate
(1) Efficient weight gain and cost reduction
Function: By taking advantage of its high density, the weight (specific gravity) of the product can be significantly increased when a relatively small volume fraction is added. This is highly beneficial for products that require a "pressing feel" (such as counterweights, imitation furniture, high-end door and window profiles, artificial marble) or products sold by weight (such as certain cable sheaths).
Economy: Under the premise of ensuring performance, barium sulfate can partially replace the more expensive PVC resin, effectively reducing raw material costs. Its low oil absorption value characteristic also saves the amount of plasticizer used.
Data: Adding 30% by weight of barium sulfate can increase the density of PVC products from approximately 1.4g /cm³ of pure PVC to around 1.8g /cm³. In applications that require a high proportion, the effect of cost reduction is remarkable.
(2) Improve processing performance
Function: Good dispersibility and low oil absorption value help improve the fluidity and processing stability of PVC melts, reduce melt breakage, and increase extrusion/calendering speed. Low volatile matter ensures that no bubbles are produced during the processing.
(3) Improving physical and mechanical properties (key!)"
Function: Compared with fillers such as calcium carbonate, high-quality barium sulfate that has undergone appropriate surface treatment has a relatively small impact on the mechanical properties of the PVC matrix under a reasonable filling amount. In some aspects (such as rigidity), it can even be improved, while better maintaining toughness (impact strength).
High modulus/rigidity: Barium sulfate itself has a moderate hardness but a high modulus. After filling, it can enhance the flexural modulus and dimensional stability of the product. This is very important for structural components such as profiles and pipes.
Maintaining impact strength: This is a major advantage of barium sulfate over calcium carbonate. Its special particle morphology and good interface combination (after treatment) can more effectively prevent crack propagation, enabling the filled PVC to absorb more energy when impacted and reducing the risk of brittle fracture.
Data support: Research shows that under the same filling amount (e.g., 20-40 phr), the notch impact strength of hard PVC filled with surface-treated precipitated barium sulfate is usually significantly higher than that of the system filled with heavy calcium carbonate of the same particle size [Reference 3, reference 4].
(4) Improve the appearance of the products
Function: High whiteness and fine particle size barium sulfate can endow products with good whiteness and covering power (for light-colored products), and help improve surface gloss and smoothness (especially in the application of film, sheet, and artificial leather surface layers). Its chemical inertness also ensures the long-term stability of the color.
(5) Endow with special functions
Improving chemical resistance: Its excellent acid and alkali resistance further enhances the chemical resistance of PVC products.
Economy: Under the premise of ensuring performance, barium sulfate can partially replace the more expensive PVC resin, effectively reducing raw material costs. Its low oil absorption value characteristic also saves the amount of plasticizer used.
Improve weather resistance: Its inertness makes it less likely to participate in photochemical reactions, which helps maintain the color and performance stability of the product when used outdoors.
02. Typical application examples
(1) PVC profiles/pipes: Enhance rigidity, dimensional stability, weather resistance, and specific gravity (partially required), and reduce costs.
(2) PVC artificial leather/floor leather: As a base filler to increase weight and reduce costs, ultrafine barium sulfate is used on the surface to enhance surface gloss, wear resistance and hand feel.
(3) PVC wires and cables: Enhance insulation (impurities must be strictly controlled), specific gravity, flame retardancy (synergistic effect), and heat resistance.
(4) PVC injection molded parts (toys, accessories) : Increase weight, reduce cost, improve surface quality.
(5) PVC film/sheet: (Using ultrafine barium sulfate) Enhances surface gloss, printability and stiffness.
03 .Recommendation: Precipitation-modified barium sulfate (Plastic direction)
Picture
|
Project |
Detailed description |
|
BaSO4(as per dry) % |
≥98.00 |
|
Water soluble substance % |
≤0.10 |
|
Average particle size um |
0.5-0.7 |
|
Fe % |
≤0.0015 |
|
Whiteness % |
≥98.50 |
|
Oil absorption g/100g |
15-25 |
|
PH Value 100g/L water |
7.0-9.0 |
|
Fineness(45u m test Mesh residue) |
≤0.08 |
04 .Conclusion
Barium sulfate is by no means a simple "filler" in PVC. It is a carefully selected and processed functional filler. Under the strict requirements of high purity, fine particle size, low oil absorption value, low volatile matter and low impurities, it brings comprehensive value of special functions such as weight increase and cost reduction, improved processing, enhanced or maintained mechanical properties (especially toughness), and optimized appearance to PVC plastics. Selecting the appropriate and compliant barium sulfate is a crucial step in producing high-performance and cost-effective PVC products.
