Baryte

Introduction

Natural baryte (barium sulphate, chemical formula BaSO₄) can be characterised by:

• High inertness in various media
• High density and, as a result, low oil absorption
• Medium Mohs hardness of 3
• Refractive Index of 1.64
• Easy wetting
• Easy to disperse (also compared to precipitated barium sulphate)

Natural barium sulphate comes without any residual salts when compared to precipitated grades. In addition, natural barytes are easier to disperse than precipitated grades.

Basic properties

Portaryte is the productname for Sibelco’s milled baryte based products. Portaryte is used as a high desnity inert filler in a wide variety of applications. Portaryte products are used in plastic applications where sound-deadening is desired, e.g in highly filled PP and PE pipes, as well as in many under the hood automotive parts (PP-based engine air intake system). Moreover, to increase the weight of an object/article and hereby changing the perception of the quality of the article, especially when made from light-weight plastic material.

The relative high refractive index of Portaryte grades also makes them very usefull as opacifiers in certain resin systems, for instance in sunroofs made from PC. Additionally the low oil absorption of Portaryte grades allows for high loading levels in compounds based on a variety of resin systems. Due to the inertness of baryte, Portaryte grades support good UV and weatherability and chemical resistance compared to conventional fillers.

Product variants

PORTARYTE B

Portaryte B is the product range for Sibelco’s natural barytes with high purity. Portaryte B grades have a low level of (transition) metal impurities (improving thermal stability of the polymer formulation) and a low silica content resulting in low abbrasion to the compounding equipment. They also exhibit high brightness. Portaryte B grades are commonly used as cost-effective replacement for precipitated barytes in applications where colour is not extremely critical. Compared to the precipitated grades they are also much easier to wet and to disperse making them more economical as less time and energy is required to make the compound.

PORTARYTE D

Portaryte D s the product name for Sibelco’s natural barytes with less purity. Designed for cost effective formulations where color is not critical and certain amount of abbrasion to the equipment can be accepted. Portaryte D grades aee preferred in compositions of friction materials (brake-pads) because of their high temperature stability or in under the hood automotive parts (PP-based engine air intake system).