Thiol-Modified Chloroprene Rubber

Thiol-modified chloroprene rubber plays a crucial role in adhesive chloroprene rubber systems due to its unique polymerization control mechanism. Thiol-modified products, especially the SN24 series, SN244X series, and SN23 series, are widely used in shoe adhesives, spray adhesives, high-grade universal adhesives, architectural decorative adhesives, and automotive interiors.

I. Mechanism of Thiol Modification

During the polymerization of chloroprene rubber, modifiers significantly affect the polymerization rate, molecular weight, distribution, and controllability of the polymerization process. Thiol modifiers, due to their moderate reactivity, are widely used in the production of adhesive chloroprene rubber.

1. More Stable Polymerization Process

Thiol modification effectively controls chain growth, maintaining suitable molecular weight and distribution, resulting in good solubility and stable processing properties. This directly affects adhesive viscosity, film-forming characteristics, and long-term storage stability.

2. Determining Initial Tack and Final Strength of Adhesives

Taking the SN24 series as an example, the molecular structure obtained through thiol regulation exhibits superior film-forming strength. When grafted with MMA (methyl methacrylate), it significantly improves adhesion to various substrates, resulting in higher initial tack and final bond strength.

3. Affecting Open Time and Working Window

The SN23 series is specifically designed for "adjustable open time." Through meticulous control of the molecular structure, it provides more flexible application times for the footwear and decoration industries, effectively improving operational convenience and production efficiency.

Thiol regulation is not merely simple polymerization control; it is a core technical means influencing the application performance of the entire adhesive system, providing a strong technical foundation for complex bonding scenarios.

II. Performance and Application Value of the SN24/SN244X Series

Among thiol-regulated chloroprene rubbers, the SN24 and SN244X series are the products with the highest market attention. SN24 focuses on bond strength and grafting applications, while SN244X further optimizes solubility, color, and weather resistance, resulting in more comprehensive overall performance.

1. SN24 Series: High-strength, graftable, and widely applicable basic products

Key features of the SN24 series include:

Thiol-modified system for stable molecular weight control

MMA grafting adaptability, further improving adhesion to substrates such as metals, leather, and rubber

High initial tack and excellent final bond strength

Suitable for fast bonding systems

Typical applications:

Shoe adhesives in the footwear industry

Spray adhesives in the furniture and packaging industries

Advanced all-purpose adhesives and engineering adhesives

SN242A is a widely used product, extensively adopted in footwear adhesive applications due to its strength, fast bonding speed, and ease of use.

2. SN244X Series: Upgraded Products with High Solubility, Light Color, and High Weather Resistance

The SN244X series optimizes several key properties based on SN24, making it a higher-end and more stable thiol-modified chloroprene rubber.

Key advantages include:

Faster dissolving speed, improving production efficiency

Lighter glue color, suitable for light-colored or appearance-sensitive products

High initial bond strength, long holding time, and better weather resistance

Less prone to aging after bonding, suitable for outdoor or strong light environments

Therefore, it is widely used in:

High-end shoe adhesives

Construction and decoration adhesives

Automotive interior bonding

Furniture and decoration industries

For companies requiring "fast dissolution + strong adhesion + high weather resistance," the SN244X series is a typical choice.

III. SN23 Series: Complementary Products Specifically Designed for Adjusting Open Time

Unlike the direct application of SN24 and SN244X, the SN23 series acts as a "modifier" in adhesive chloroprene systems. Its core value is adjusting the open time.

1. Why is open time so critical?

In adhesive applications, too short an open time leads to application difficulties; too long an open time reduces efficiency. Different seasons, application temperatures, and substrate conditions can all cause fluctuations in the final bonding effect.

The SN23 series allows for precise adjustment of the adhesive's drying speed and operating window, ensuring stable performance under various environmental conditions.

2. Enhanced results when used in conjunction with SN24/SN244X

The SN23 series is typically not used alone, but rather in combination with SN24 and SN244X, serving the following purposes:

Extending or optimizing adhesive open time

Improving sprayability and application feel

Optimizing the balance between initial and final bond speeds

Enhancing adaptability to complex processes

Typical products such as SN236T and SN237T possess suitable solution viscosity and good stability, making them highly valuable in the footwear and industrial adhesive industries.

As industries such as footwear manufacturing, furniture decoration, and automotive interiors demand increasingly higher performance from adhesives, adhesive-grade neoprene rubber is entering a stage of development focused on higher performance, greater controllability, and greater stability.

The thiol-modified SN24, SN244X, and SN23 series are key components of this trend:

SN24 – High strength, graftable, and comprehensive adhesive properties

SN244X – An upgraded solution offering fast dissolution, light color, and high weather resistance

SN23 – An open-time modifier product that makes production more controllable.

Through proper combination, these adhesives can create more stable, easier-to-process, and more adaptable neoprene adhesive systems, bringing higher efficiency and better bonding quality to end-user industries.