Finally, someone clarifies "pvc foaming agent"!

Apart from the complex chemical formulas,The most intuitive function of a foaming agent.Sure, please provide the content you would like to be translated into English.During the plasticization of PVC, gases are decomposed to form a large number of tiny bubbles, turning solid plastic into a porous structure.

Imagine PVC resin as a lump of sticky dough, with the foaming agent like "baking soda" hidden inside the dough.Heat to a certain temperature.The foaming agent decomposes, releasing gases such as nitrogen and carbon dioxide with a "puff, puff, puff" sound.The gas is wrapped, stretched, and shaped by molten PVC.Eventually forming individual or interconnected bubbles.

A foaming agent essentially is a chemical or physical substance that can controllably release gas within a specific temperature range and stabilize into foam within the PVC melt.

The "birth, growth, and stabilization" of micro-bubbles directly determine the "lightweight, thermal insulation, and cushioning" properties of macro materials!

The "Gas Magician" makes a move, and the material properties are transformed dramatically!

Understanding how foaming agents create pores reveals why they are the "core engine" for the lightweighting of PVC.

1. The "Light and Heavy Switch" of Density and Weight：

No foaming agent added:The density of PVC is typically around 1.4 g/cm³, making it solid and heavy.

Add foaming agent:The density can be reduced to 0.5 g/cm³ or even lower.Easily achieve more than 50% weight loss.The costs of handling, installation, and transportation have significantly decreased.

2. The "strength-weakness balance" of mechanical properties:

The foam cells are uniform and dense.The material remains strong, resilient, and compressive while being lightweight, making it suitable for lightweight structural components.

Coarse and uneven foam cellsProne to collapse, sudden drop in strength, the product becomes limp and weak, turning into waste.

3. Insulation and soundproofing "feature enhancement":

The thermal conductivity of the gas inside the bubbles is extremely low.Foamed PVC has become an excellent insulating material (such as building insulation boards).

Porous structure effectively blocks sound wave propagation.Suitable for door and window seals, soundproof gaskets, etc.

4. "Texture Upgrade" in Touch and Appearance:

Surface is dense, interior is foamed.Achieve a solid feel and lightweight core, such as simulated wood plastic board.

Uniform overall foamingSoft and elastic, like yoga mats and sneaker midsoles.

A foaming agent is not "just added"; it is a precise art of coordination between temperature, time, pressure, and formulation.By cleverly selecting the type of foaming agent, combining additives, and controlling the process in the formulation, you can make the bubbles obey your command.

Blowing Agent Types: "Chemical" vs "Physical"

- Chemical foaming agents (such as AC foaming agents)：像“定时炸弹”，在特定温度分解产气，气体量可控、泡孔细密，是PVC发泡的绝对主力。

· Physical foaming agent (such as CO₂、N₂）"Direct inflation" involves high-pressure injection, is environmentally friendly with no residue, but has high equipment requirements, and is commonly used in high-end extrusion or injection foaming.

Temperature Control: "Flashpoint" and "Stability Zone"

The decomposition temperature must match the PVC plasticizing temperature.Producing gas too early leads to gas escape; producing gas too late results in uneven gas dispersion.

The foaming agent needs to synergize with heat stabilizers and lubricants to ensure proper decomposition, nucleation, and expansion within the screw.

Nucleating agent: "Seeds of bubbles"

Add nano calcium carbonate, talcum powder, etc.Provide nucleation sites for bubbles, making them finer and more uniform, and preventing them from merging into larger pores.

Melt strength: "The cage of bubbles"

Add acrylic additives, partially crosslinked PVC, or Rongjia toughening modifiers.Increase the melt strength to prevent bubbles from breaking or collapsing during the expansion process.

Recipe Combination: "Strength and Gentleness Combined"

Adjust the amount of plasticizer.Controlling the melt viscosity affects the bubble growth rate and the final pore size.

- Select the appropriate grade of PVC resinThe K value is moderate, and the molecular weight distribution is reasonable, which is conducive to pore stability.