Specifications

Appearance	White homogeneous paste
Assay	48.5-51.0 %

Characteristics

Density, 20 °C	1.200 g/cm³
Viscosity, 20 °C	thixotropic paste mPa.s

Applications

BPO-TW50 is a paste containing 50% dibenzoyl peroxide without phthalate for the curing of unsaturated polyester resins at ambient and elevated temperatures. At temperatures up to 80°C, BPO-TW50 should be used in combination with an aromatic tertiary amine accelerator, above 80°C the use of an accelerator is not required. BPO-TW50 has primarily been developed for the putty market. For non filled systems, BPO-TW50 40E is better applicable with respect to miscibility with the UP resin. BPO-TW50 shows a very good chemical and physical stability and is therefore very suitable for tube filling. The curing system BPO-TW50/amine accelerator shows a very fast cure that is hardly influenced by humidity and fillers. Even at low temperatures a relatively good cure will be obtained. A disadvantage may be the yellow color and poor light resistance of the moulded product.

Thermal stability

Organic peroxides are thermally unstable substances, which may undergo self-accelerating decomposition. The lowest temperature at which self-accelerating decomposition of a substance in the original packaging may occur is the Self- Accelerating Decomposition Temperature (SADT). The SADT is determined on the basis of the Heat Accumulation Storage Test.

SADT	50°C (122°F)
Emergency temperature (T。 )	45°C (113°F)
Control temperature (Tc)	40°C (104°F)
Method	The Heat Accumulation Storage Test is a recognized test method for the determination of the SADT of organic peroxides (see Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria – United Nations, New York and Geneva).

Storage

Due to the relatively unstable nature of organic peroxides a loss of quality can be detected over a period of time. To minimize the loss of quality, Thousands Chemicals recommends a maximum storage temperature (Ts max.) for each organic peroxide product.

Ts max.	25°C (77°F)
Note	When stored under the recommended storage conditions, BPO-TW50 will remain within the Thousands Chemicals specifications for a period of at least 3 months after delivery.

Packaging and transport

In North America BPO-TW50 is packed in 45 lb plastic pails. In other regions the standard packaging is plastic pails for 20 kg peroxide. Both packaging and transport meet the international regulations. For the availability of other packed quantities contact your Thousands Chemicals representative. BPO-TW50 is classified as Organic peroxide type E; solid; Division 5.2; UN 3108.

Safety and handling

Keep containers tightly closed. Store and handle BPO-TW50 in a dry well-ventilated place away from sources of heat or ignition and direct sunlight. Never weigh out in the storage room.Avoid contact with reducing agents (e.g. amines), acids, alkalis and heavy metal compounds (e.g. accelerators, driers and metal soaps). Please refer to the Safety Data Sheet (SDS) for further information on the safe storage, use and handling of BPO-TW50. This information should be thoroughly reviewed prior to acceptance of this product.

Major decomposition products

Carbon dioxide, benzoic acid, benzene, diphenyl, phenyl benzoate