Product Name: LUPEROX® F40P-SP2
Chemical Name: Bis(tert-butyl isopropyl peroxy)benzene
CAS Number: 25155-25-3
Product Description:
Luperox® 40P-SP2 is a scorch protection product derived from Luperox® F40P. It uses calcium carbonate and silica as dispersing carriers and has a concentration of 40%. It is specifically designed to provide excellent scorch protection during extrusion molding for various rubbers, including EPDM, HNBR, and CPE. Its chemical structure is:
1,3,1,4-Bis(tert-butylperoxyisopropyl)benzene
Molecular weight: 338.5 g/mol
Key Properties
Form: Powder
Peroxide Content: 40%
Reactive oxygen content: 3.8%
Scorch Protection
Luperox® 40P-SP2 provides excellent scorch protection and addresses the shortcomings of traditional antioxidants.
As shown in Figure 1, its main advantages over traditional antioxidants are:
It can scavenge free radicals relatively quickly to provide good scorch protection;
comparable crosslinking levels (crosslinking levels are not reduced).
Performance
In EPDM (EPDM DUTRAL TER 4049) compounds, the vulcanization performance of Luperox® F40P-SP2, Luperox® F40P, and Luperox® F40M-SP is as follows. The peroxide content is 8 phr.
Luperox® F40P-SP2 and Luperox® F40M-SP extended the protection time, or “scorch time at vulcanization temperature” (t s2 at 190°C), by 30% and 18%, respectively, compared to Luperox® F40P.
At 145°C, the Mooney viscometer measured excellent scorch protection:
The scorch protection time (t s05) of Luperox® F40P-SP2 is three times that of Luperox® F40P
Advantages
The excellent scorch protection provided by Luperox® F40P-SP2 offers numerous advantages.
Cost Reduction
The excellent scorch protection inherent in Luperox® F40P-SP2 reduces the amount of antioxidants required in the formulation
Compounding
Productivity can be increased by raising the mixing speed.
A two-step mixing process can be converted to a single-step process.
Good scorch protection extends the mixing time, resulting in a more uniform compound.
Vulcanization
In injection molding, a longer protection time reduces scrap. Mold design can be optimized (more cavities), which improves production efficiency and is better suited for peroxide-cured rubber products. Additionally, higher mold temperatures can be used to boost production efficiency, enabling faster mold filling and faster curing.
In extrusion processing, both extrusion temperature and speed can be increased to boost production efficiency. Effective scorch protection reduces downtime for cleaning equipment (due to gel buildup) and increases production time.
Main Applications
Luperox® F40P-SP2 was developed specifically for processing applications requiring strict scorch protection, such as injection molding or the vulcanization of reactive polymers (HNBR or CPE). As a result, it can be used in a wide range of products. For example:
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- O-rings;
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- Molded parts;
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- Hoses and window frames;
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- Rubber sealing strips and gaskets;
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- Wires and cables;
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- EPDM and EVA shoe soles.
Addition Level
The general addition levels for Luperox® F40P-SP2 are listed in the table below:
EPDM: 6–12
HNBR: 6–10
CPE: 4–8
Decomposition Products
In an inert medium, the main decomposition products of Luperox® F40P-SP2
are the same as those of F40P:
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- acetone;
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- tert-butanol;
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- methane;
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- diphenylacetone;
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- bis(isopropyl)benzene.