For manufacturers aiming for precision and excellence in plastic foaming, a thorough understanding of the technical specifications of NC blowing agents is indispensable. NINGBO INNO PHARMCHEM CO.,LTD. breaks down two of the most critical parameters: gas evolution and decomposition temperature, and explains their profound impact on the foaming process and final product quality.

Decomposition Temperature: The Key to Controlled Foaming
The decomposition temperature of an NC blowing agent is the temperature at which it begins to break down and release gas. This is arguably the most crucial technical specification, as it must be carefully matched to the processing temperature of the polymer being foamed. For PVC processing, which typically occurs in the range of 170-200°C, NC blowing agents are often formulated to decompose within this window, or slightly below it, to ensure gas release occurs during the desired phase of processing.

NC blowing agents are generally characterized as endothermic foaming agents, meaning they absorb heat during decomposition. This property allows for a more controlled and gentle gas release compared to exothermic agents. A typical decomposition temperature range for many NC blowing agents used in PVC is between 130°C and 170°C. The precise temperature is critical: if it's too low, the agent may decompose prematurely during compounding, leading to loss of blowing efficiency or unwanted gas release. If it's too high, it may not decompose sufficiently during the molding or extrusion process, resulting in poor foaming or no foaming at all.

The stability of the decomposition temperature is also important. A blowing agent with a narrow decomposition temperature range ensures consistent gas release, leading to uniform cell formation and predictable product properties. Manufacturers must select an NC blowing agent whose decomposition profile complements their specific PVC resin and processing equipment.

Gas Evolution: The Measure of Foaming Capacity
Gas evolution, typically measured in milliliters of gas per gram of blowing agent (ml/g) at standard temperature and pressure (STP), quantifies the amount of gas a blowing agent can produce. For NC blowing agents, this value generally ranges from approximately 115 ml/g to 160 ml/g or higher, depending on the specific chemical composition and structure.

The gas evolution rate dictates the volume expansion achieved during foaming. A higher gas evolution capacity, when properly controlled by the decomposition temperature and processing parameters, can lead to lower density products. However, simply having a high gas evolution value is not always the goal. The *rate* at which this gas is released is equally important. NC blowing agents are known for their relatively moderate gas evolution rates and longer foaming times, which facilitate better control over the cell structure, leading to finer and more uniform bubbles. This contrasts with some exothermic blowing agents that release gas very rapidly, potentially causing large, irregular cells or even cell rupture.

Manufacturers often utilize a combination of NC and other blowing agents to optimize gas evolution characteristics. For example, mixing an NC agent with an AC agent can provide a balance between controlled gas release and overall foaming capacity, resulting in products with superior surface finish and mechanical properties.

Understanding these technical specifications allows manufacturers to precisely control the foaming process, tailor the properties of their PVC foam products, and achieve desired outcomes such as optimal density, superior insulation, and excellent mechanical strength. NINGBO INNO PHARMCHEM CO.,LTD. provides detailed technical datasheets for its NC blowing agents, empowering customers to make informed choices and excel in their plastic foaming applications.