There are three main types of release agents used in manufacturing: internal release agents which are added directly to composite materials, conventional or non-permanent release agents which require reapplication for each cycle due to being solvent-based, and semi-permanent release agents which form protective barriers and allow for multiple releases without affecting product strength. Semi-permanent release agents, including water-based suspensions, are most commonly used today in composite molding due to reducing costs and cycle times compared to other options.

1. Types of Release Agents
Manufacturers produce myriad products in a variety of shapes and sizes using
molds. These products as well as molds are made in many materials like plastic,
concrete, metals, ceramic, glass etc.

3. Molding allows the manufacturer to produce articles in the exact same
dimensions and designs in the shortest possible time. While molding an article, a
time comes when the composite material has to be separated (de-molded) from
its mold. This is where release agents function. A release agent basically creates a
slip effect between the mold article and the mold.
Release agents can broadly be divided into 3 categories:
1. Internal Release Agents
2. Conventional or Non-Permanent Release Agents
3. Semi-Permanent Release Agents
Internal Release Agents
These are specialty release agents which are utilized by select applications only.
As the name suggests, internal release agents are added to the composite
material in order for the external release agents to function efficiently for
example in the construction industry and tyre moulding industry.

4. Conventional or Non-Permanent Release Agents
These are used where high slip or lubrication is a prime requirement. For example
in order to build a tube-like structure, the composite is likely to shrink tightly
around the mandrel. Here, a high lubrication, conventional release agent is
required to prevent the composite from binding itself to the forming mandrel and
at the same time provide a high-slip for the part to slide off easily without
affecting its strength and structure.
Conventional release agents are often solvent based and either aromatic or
aliphatic. Often, to make them non-flammable and soluble, volatile chlorinated
hydrocarbons and chloro-fluorocarbons are used. (Cellular Polymers by Dr.
Wilhelm Schroder).
Also known as Non-Permanent release agents, these are required to be applied at
every cycle.
In modern mold release applications, conventional release agents are being used
far less than the third type.
Semi-Permanent Release Agents
SPMRAs are designed to serve dual purpose. They form a protective barrier on
the mold surface from different forms of chemical and mechanical attacks and at
the same time offer an easy release of the composite.
In almost all composite molding applications these days, Semi-Permanent release
agents are used.
SPMRAs can be solvent or water based. These inert formulations are designed to
enable multiple releases per application; hence reduce cost and cycle times as
compared to conventional release agents. Supervac Industries manufactures
Boron Nitride water based suspension under the brand
name- Boronox and Boronox+ and graphite water based suspension under the
brand name-Graphinox in order to cater to this wide segment of release agents.

5. SPMRAs come in powder form also. Supervac Industries’ Boron Nitride powders in
various grades are SPMRAs in powder form.

6. Precautions:
While selecting a release agent, it will help the manufacturer to keep certain
considerations in mind. For example, the selected release agent should not react
in any way with the composite material, internally as well as externally. Often, a
wrong parting agent leaves the surface of the molded article with unwanted
results like pits or scars etc. The selected release agent must be inert to the
composite material and the mold material alike.
The amount of slip required is also of paramount importance. Sometimes difficult
geometrics of the mold require more slip at one place than at others.

7. A wrong choice of a release agent can mar the end result.
Another important consideration is how safe or unsafe a particular release agent
is for humans and also the environment. Often the release agents are sprayed on
to the molds, sending vapors and minute particles of it into the air.

8. Sometimes, the release agent is manually applied with a paint brush by workers.
Therefore it is of utmost importance that the selected release agent be quite safe
for humans.
Apart from the slip effect, often the manufacturer desires certain types of finishes
on the mold article surface e.g. a gloss or matte effect.

9. For this, specialty release agents are employed.