Overview of PBT Additives

Overview of PBT Additives

PBT crystallizes rapidly, making it prone to warpage. The shrinkage of PBT materials is generally 1.5%–2.8%, while for materials with 30% glass fiber content, the shrinkage is 0.3%–1.6%. The melting temperature of PBT (225°C) is lower than that of PET (260°C). Both PBT and PET have low melt viscosities and short molding cycle times.

I. Flame Retardants

1. Brominated flame retardants

2. Antimony-based synergists such as sodium antimonate

In acid-sensitive polymers and polyester materials, conventional flame retardant synergist antimony trioxide can cause material degradation during processing. Sodium antimonate, with low reaction activity, doesn’t easily lead to processing degradation in materials like PET, PBT, and PC. It can increase the CTI value. With a low refractive index and low coloring strength, it minimally affects the transparency of polymer materials and allows pigments to maximize coloring efficiency, facilitating material coloring and reducing dyeing costs.

3. Flame retardant smoke suppressants

Zinc borate can be used as a flame retardant and smoke suppressant in plastics. Due to its extremely low heavy metal content, it is especially suitable for electronic products.

Zinc stannate (ZS) can be used as a multifunctional flame retardant and smoke suppressant in plastics, rubbers, and coatings, and can replace antimony trioxide.

II. Compatibilizers and Toughening Agents

1. Toughening agent

2. Compatibilizer

European NGC's 16MA11F is a high-elastic graft modifier that can improve the compatibility between polar and non-polar polymers or serve as a bonding promoter between metals and other polar substrates. It meets food contact standards.

Product applications:

• An efficient compatibilizer for polar and non-polar polymers. compatibilizer for PBT and polyolefins

• Coupling agent for GF, CF, and mineral fillers

• Flexible bonding promoter on metals or other polar substrates

III. Porous Graphite Wear-Resistant Agents

High-rebound porous graphite, derived from electrothermal treatment/purification technology, boasts high purity and graphitization degree with excellent resilience. It features low wear, vibration damping, ease of design, and lightweight properties. It has been widely used in various polymer materials, including engineering and high-performance thermoplastics, thermosetting plastics, PTFE, and coatings, in automotive, household, and industrial equipment.

Porous graphite types such as RGC39A, RGC26A, 5926, and 5933 are mainly used to reduce wear.

After continuous electrothermal treatment/purification, the raw material partially transforms into a typical hexagonal graphite structure, significantly enhancing purity and altering appearance. The porous graphite exhibits unique properties like high purity, high porosity, controlled graphitization degree, stable particle size distribution and shape (meeting sensitive application requirements), and high resilience.

IV. Processing Flow Aids

1. Fumed nano-silica

NanOsil ASD is a super-fine (sub-micron), white, spherical, non-agglomerated, non-porous, high-purity, amorphous silica powder produced via high-temperature hydrolysis in a hydrogen-oxygen flame.

In PBT filling systems, adding 0.4%-1% NanOsil ASD can shorten molding time, improve flow marks, pigment dispersion, and mechanical/physical properties. With an addition of less than 1%, it complies with FDA certification.

2. Silicone powder

Silicone powder offers good thermal stability and anti-migration properties in PBT systems. Especially in glass fiber-reinforced or filled PBT systems, it significantly enhances product lubricity, demolding, and fluidity, reduces screw torque and energy consumption, and makes mold filling easier, lowering defect rates. It reduces the surface friction coefficient of PBT products, improves slipperiness and a silky surface feel, increases scratch resistance, and boosts the surface gloss of reinforced or filled products. It also improves flame retardancy and reduces smoke density.

3. Indonesian EBS

CMS CHEM is a functional chemical EBS manufacturer with over 30 years of technical experience. It has the highest production level in the industry and holds a 30% global market share. The product is a white powder or granule with a slight fatty odor, insoluble in water, and its powder becomes wettable above 80°C. It is stable to acids, alkalis, and water media. At room temperature, it is insoluble in most solvents like ethanol, acetone, and carbon tetrachloride but dissolves in hot chlorinated hydrocarbons and aromatic hydrocarbons. Upon cooling, the solution forms precipitates and gels. Non-toxic and safe for food industry applications, it provides internal and external lubrication in PBT systems.

V. Deodorizers

Inzeo mono 15/5 is a treated and optimized zeolite with adsorption properties. It reduces odor and VOCs in PBT applications and is effective in automotive parts, home appliance components, building materials, flooring, and packaging. The recommended addition is 1%-2%.

VI. Phthalocyanine Pigments

Indian phthalocyanine blue ST-2900, with its unique blue shade and excellent lightfastness, weather resistance, and heat resistance (up to 350°C), and good dispersibility and stability, is widely used in plastics, rubbers, and coatings. It performs well in both coloring and shade correction and is compatible with various polymers, water-based coatings, and primers. Its high-quality phthalocyanine mineral source and pigment dispersing/wetting technology are from India.

VII. Nucleating Agents

PW-50B enhances nucleation in reinforced PBT, shortening crystallization time and improving demolding efficiency. It also improves the following properties in PBT reinforcement systems:

1. Shortens molding cycle

2. Facilitates mold filling

3. Easier demolding

4. Better dimensional stability of extruded or injection-molded products

5. Higher thermomechanical properties

PBT is widely used in household appliances (e.g., food processor blades, vacuum cleaner components, fan housings, hairdryer casings, coffee utensils), electrical components (switches, motor housings, fuse boxes, computer keyboard keys), and the automotive industry (radiator grilles, body panels, wheel trims, window and door components).

YINSU Company has long been dedicated to the field of flame retardancy and offers a variety of flame retardant products for plastics. With extensive expertise and a strong emphasis on innovation, YINSU provides high-quality solutions for PBT, such as red phosphorus flame retardants FRP-604H and FRP-750AH, as well as halogen-free flame retardant PBT-WL-20M. Our products aim to enhance fire safety while maintaining the inherent properties of PBT materials, making them suitable for various applications across different industries.