Coupling agents are a class of substances with two functional groups of different properties. Some of the functional groups in their molecules can react with organic molecules, and the other functional groups can react with the adsorbed water on the surface of inorganic substances to form a firm bond. The role of the coupling agent in the composite material is that it can not only react with some groups on the surface of the reinforcing material, but also react with the matrix resin to form an interface layer between the reinforcing material and the resin matrix, and the interface layer can transmit stress, Therefore, the bonding strength between the reinforcing material and the resin is enhanced, and the performance of the composite material is improved. At the same time, it can prevent the penetration of other media into the interface, improve the interface state, and is beneficial to the aging resistance, stress resistance and electrical insulation properties of the product. .

According to the chemical structure and composition of the coupling agent, it is divided into four categories: organic chromium complexes, silanes, titanates and aluminates:

(1) Chromium complex coupling agent Chromium complex coupling agent was developed in the early 1950s, and the synthesis and application technology of metal chromium complexes formed by unsaturated organic acids and trivalent chromium ions are relatively mature, and The cost is low, but the variety is relatively single.

(2) Titanate coupling agents According to their unique molecular structure, titanate coupling agents include four basic types: ①Monoalkoxy type This type of coupling agent is suitable for a variety of resin-based composite material systems, especially Suitable for filling systems containing no free water, only chemically bound water or physical water; ②Monoalkoxy pyrophosphate type This type of coupling agent is suitable for various resin-based composite material systems, especially suitable for high moisture content 3. This type of chelating type coupling agent is suitable for various resin-based composite material systems. Because of their very good hydrolysis stability, this type of coupling agent is especially suitable for water-containing polymer systems; 4. Ligand type This type of coupling agent has good coupling effect in various resin-based or rubber-based composite material systems, and it overcomes the shortcomings of general titanate coupling agents used in resin-based composite material systems.

(3) Other coupling agents Zirconium coupling agents are low molecular weight inorganic polymers containing zirconium aluminate. It can not only promote the adhesion between different substances, but also improve the properties of the composite material system, especially the rheological properties. This type of coupling agent is suitable for both thermosetting resins and thermoplastic resins. In addition, there are magnesium-based coupling agents and tin-based coupling agents.

Coupling agent

In reinforced plastics, chemical substances that can improve the bonding force between the resin and the reinforcing material interface.

A substance that promotes or establishes a strong bond at the interface between the resin matrix and the reinforcing material.

Note: The coupling agent can be applied to the reinforcing material or added to the resin, or both.

Application areas Main functions

Glass fiber and glass fiber reinforced plastic: Improve the wet physical and mechanical strength and wet electrical properties of composite materials, and improve the clustering, protection and processing technology of glass fiber.

Adhesives and coatings: Improve wet adhesion, weather resistance, pigment dispersion, abrasion resistance and resin crosslinking.

Casting: Improve the strength of resin sand. In order to achieve high, low gas.

Rubber: Improve the mechanical strength, wear resistance, wet electrical properties and rheology of products.

Sealant: Improve the adhesion in wet state, improve the dispersion of fillers, and improve the wear resistance of products.

Textiles: Soften and plump textiles, improve their water resistance and adhesion to dyes.

Printing ink: Improve the wettability of adhesion.

Filler surface treatment: Improve the compatibility, wettability and dispersibility of filler and resin in resin.

Cross-linked polyethylene: used to strengthen the strength of cross-linked polyethylene cables and hot water pipes. Durability and service life.