The use of adhesive integrated knowledge of four

4. Different adhesive types

We are divided into two kinds of dissolved adhesives and binders.

4.1 Dissolving adhesives

Dissolving adhesives are only used to join the same or similar thermoplastic materials. Dissolving agents are applied to the mating surfaces and the components are assembled and tightly clamped together after painting. After the solvent is dissolved, good bonding can be achieved. (usually better than the adhesive)

4.2 Binder

Available with one or more than two binders. Choosing the right adhesive depends on the materials to be bonded and the working conditions.

Listed below are the most important binders for plastics and their main properties

4.2.1 Epoxy Bonding Directory

4.2.1.1 Description and Performance

Epoxy adhesives are thermosetting resins.

The two-component resin/hardener system solidifies after mixing (consolidation is mostly promoted by heating). In the single-component epoxy resin, the two components have been mixed and only heated to solidify.

Bonding amorphous thermoplastics (PC, PPSU, PEI, PSU) with two-component amine-containing epoxy resin adhesives causes stress cracking; conducts compatibility tests and/or obtains from adhesive suppliers instructions.

Compared with other adhesives, epoxy bonding has high shear strength and good creep properties. However, spalling and impact strength are relatively low, but the use of "toughened" adhesives can improve. These adhesives contain dispersed rubber to prevent crack propagation.

Epoxy adhesives are widely used and enjoy a good reputation.

range of working temperature

Two component adhesives: -50 to +80°C
One component adhesive: -50 to 120°C (also available in 200°C types)

4.2.1.2 How to use

Follow the manufacturer's instructions for use. The required two ingredients were carefully weighed and mixed.
Apply the mixture to a joint surface. The parts are immediately assembled and clamped together until sufficient strength to move is achieved.
Normally the solidification time is long, but it can usually be shortened by heating.
The heat resistance of the binder should be kept in mind.

4.2.1.3 Precautions

Epoxy resin is relatively safe.
It is recommended to avoid contact with the skin and provide a well-ventilated workshop.

4.2.2 Polyurethane Adhesives Directory

4.2.2.1 Description and Performance

It is usually a two-component adhesive. One of them is based on isocyanate. It can be used as a low-viscosity polyurethane, but it is harmful to health because of its low molecular-weight reaction. Therefore, it is best to use higher viscosity grades when working.
The two components react rapidly at room temperature and form a polymer.

These adhesives provide a strong, resilient bond that can bond many materials.

Has high impact strength, and good anti-stripping force. It has general purpose but its high viscosity and solidification rate can be limited.
Can not be used in hot and humid environment.

Operating temperature range: -50 to +80°C

4.2.2.2 How to use

Follow the manufacturer's specific guidelines for each adhesive. The working environment should be as dry as possible because atmospheric moisture can affect the isocyanate resin, which can disrupt the solidification process.

4.2.2.3 Precautions

Health care is required to reach a high level because isocyanate is physiologically active. This should review the detailed considerations for ventilation in the workshop and require employees to be more alert.

4.2.3 Solvent-Containing Rubber Adhesives (Contact Adhesives)

4.2.3.1 Description and Performance

These adhesives are based on natural and artificial rubber solutions ranging from low viscosity solutions to highly viscous pastes and semi-solids.
It is solidified by evaporation and/or solvent absorption at room temperature.

These adhesives are simple to use and can be used in nearly all materials. These materials are not corroded by solvents.

Bonding amorphous thermoplastics (PC, PPSU, PEI, PSU) with solvent-containing rubber adhesives can cause stress cracking; conduct compatibility tests or obtain guidance from adhesive suppliers.

Solvent-containing rubber adhesives are particularly suitable for applications where they require elasticity, light load, and less need to provide a working environment.

There are different types of high speed and viscosity properties that are used in fine work.

Thermal coagulation types (vulcanization type) are usually used at high load bearing joints.

The adaptability of its adhesive thermoplastic depends mainly on the solidification temperature.

Operating temperature range: -30 to +80°C (to be continued)