In recent years, silicone "squeezable toys" have become increasingly popular, and our hydrogen-containing silicone oil plays a crucial role behind the scenes.
Hydrogen-containing silicone oil is used as a crosslinking agent (curing agent) and modifier for silicone, enabling liquid silicone mixtures to solidify into the elastic "squeezable" toys we hold in our hands.
One. Core Function: Crosslinking Agent (Curing)
This is the most important and core function of hydrogen-containing silicone oil.
1. Basic Principle:
The base adhesive used in "squeezable toys" is usually vinyl silicone oil, whose molecular chains contain vinyl groups.
Hydrogen-containing silicone oil has active silicon-hydrogen bonds (Si-H) on its molecular chains.
Under the action of a platinum catalyst, the vinyl groups and the Si-H bonds undergo an addition reaction (hydrosilaneation reaction). This reaction is like countless small "bridges" (Si-H) connecting long chains (vinyl silicone oil) to form a three-dimensional network structure.
Process Analogy:
Before the reaction: Vinyl silicone oil (liquid) + Hydrogen-containing silicone oil (liquid) + Platinum catalyst + colorant, etc. = Mixed liquid (can be poured into a mold).
After the reaction: Through heating or leaving at room temperature, a chemical reaction occurs, and the liquid crosslinks into a solid, elastic silicone network.
2. Impact on the properties of "squeezable silicone":
Controlling Hardness: The amount of hydrosilicone oil added is one of the key factors controlling the final hardness of "squeezable silicone."
Higher addition: Higher cross-linking density, tighter molecular network, resulting in a harder "squeezable silicone."
Low addition: Lower cross-linking density, looser molecular network, resulting in a softer "squeezable silicone."
Manufacturers can produce products with different textures, from ultra-soft to relatively hard, by precisely controlling the amount of hydrosilicone oil used.
Determining Molding: Without hydrosilicone oil, silicone cannot transform from a liquid to a solid, and therefore, "squeezable silicone" cannot exist.
Two. Secondary but Important Role: Modifier
Besides acting as a crosslinking agent, hydrogen-containing silicone oils offer several additional beneficial properties.
1. Improved Mechanical Properties: Proper crosslinking imparts good tear strength and abrasion resistance to silicone, allowing "squeezable toys" to be repeatedly kneaded and stretched without easily breaking, thus extending their lifespan.
2. Improved Surface Hydrophobicity: Hydrogen-containing silicone oils are inherently hydrophobic. After the crosslinking reaction, some hydrophobic groups remain on the silicone surface, making "squeezable toys" water-resistant, less prone to water stains, and easier to clean.
3. Enhanced Internal Lubrication (Secondary): In the curing system, an appropriate amount of hydrogen-containing silicone oil can provide some internal lubrication, resulting in a smoother feel after curing.
Three. Key Application Points in the Production of "Squeezable Silicone" Products
1. Addition Ratio: The amount of hydrogen-containing silicone oil added needs to be very precise, typically between 0.5% and 3% of the total weight of the silicone system, depending on the required hardness, the type of base silicone, and the active hydrogen content. This is a technical task requiring manufacturers to conduct repeated trials to determine the optimal formula.
2. Synergy with Catalyst: A platinum catalyst must be used to initiate the reaction. Platinum catalyst and hydrogen-containing silicone oil are a perfect match, jointly determining the speed and efficiency of curing.
3. Process Requirements:
Uniform Mixing: The hydrogen-containing silicone oil must be thoroughly and quickly mixed uniformly with the base silicone, colorant, and other components. Otherwise, uneven curing will occur, resulting in some areas being soft, some areas hard, or even uncured areas (sticky).
Avoidance of Poisoning Substances:Hydrogen-containing silicone oil and platinum catalysts are highly sensitive to certain substances, such as compounds containing nitrogen, phosphorus, and sulfur, as well as tin catalysts. These substances can "poison" the catalyst, leading to incomplete curing or no curing at all. Therefore, the pigments, fragrances, containers, etc. used in the production process must be ensured to be specifically for the "platinum vulcanization system".
Four. Summary of Advantages of Hydrogen-Containing Silicone Oil
For toys like "squeezable toys," addition-cure silicone using hydrogen-containing silicone oil as a crosslinking agent offers the following significant advantages compared to other types of silicone (such as condensation-cure silicone):
Environmentally Friendly and Non-Toxic: The addition reaction does not produce byproducts; the cured silicone is pure, non-toxic, and odorless, meeting toy safety standards.
Deeply Curable: It can cure very thick layers, suitable for creating "squeezable toys" of various shapes and sizes.
High Transparency: The cured silicone has excellent transparency, ideal for creating high-quality "squeezable toys" containing sequins, cartoon characters, etc.
Low Shrinkage: Stable molding dimensions allow for precise replication of mold details.
Excellent Physical Properties: Provides excellent resilience, tensile strength, and durability.
Conclusion
In summary, hydrosilicone oil is the key chemical that brings silicone "squeezable toys" to life. Through a precise chemical reaction, it transforms a liquid into a solid toy with perfect elasticity and feel. By controlling the type and amount of hydrosilicone oil, manufacturers can design a wide variety of "squeezable toy" products to meet different market demands for softness, durability, and appearance. Although consumers cannot see it in the finished product, it is an indispensable core technology behind high-quality "squeezable toys."
