A mold release agent is a chemical substance used in industrial production whose main function is to form an interfacial coating between two surfaces that tend to stick together, making the surfaces easier to detach, smooth, and clean. Mold release agents are chemically resistant and have heat and stress resistance properties that do not dissolve in contact with the chemical components of different resins (especially styrenes and amines) and do not readily disintegrate or wear off. The material bonds to the mold but does not transfer to the part being processed, so it does not interfere with painting or other secondary processing operations.
The main function of release agents in the manufacturing process is to prevent or reduce mechanical damage to molded products when they come out of the mold. There are many types of mold release agents, including non-silicone and silicone types. Why apply silicone mold-release agents?
Non-silicone mold release agents are not as lubricious as silicone release agents; they are also not as durable as silicone release agents and require more frequent reapplication. While silicone mold release agent is prepared from silicone as raw material, its advantages are good heat resistance, moderate surface tension, ease to form a uniform isolation dry film, so you can start molding immediately, have quick silicone mold release, long life of the release non-toxic, good luster, do not affinity with the resin, etc., which is widely used in the field of plastics, metal casting, automobile manufacturing and so on.
Here’s some information about it:
- What is the principle of mold release agent?
- How to classify mold-release agents?
- How to use silicone mold release agents?
- How to choose the silicone mold release agent raw material?
- How to make silicone mold release agents better performance?
1. What is the principle of mold release agent?
Rubber and plastic products in the mold molding process, rubber and plastic materials, and mold surface contact may be due to the mold surface bump and other micro-defects, rubber and plastic products from the mold will have a certain amount of friction resistance when peeling. Rubber and plastic in the injection or extrusion process, rubber and plastic materials and molds are often formed between the negative pressure, or between the two due to physical adsorption or chemical bonding and bonding. The result is that in the molding of rubber and plastic products from the hot molds, there are peeling difficulties.
To weaken the products and mold adsorption or bonding, often used to form an effective isolation film additive - mold release agent.
2. How to classify mold-release agents?
Broadly speaking, there are many types of mold release agents specially formulated, that are used in the chemical industry, metallurgy, building materials, and other fields.
2.1 Commonly used release agents
Many kinds of basic substances can be used as mold-releasing agents. Commonly used mold-releasing agents are inorganic substances, organic substances, and polymers.
(1) Commonly used inorganic release agents are graphite powder, talcum powder, mica powder, molybdenum disulfide and other powders;
(2) Commonly used organic substances class mold release agent has fatty acids, fatty acid soap, various waxes, glycol, etc., this type of release agent also has the role of lubricant;
(3) Polymer-based release agents are mainly polyvinyl alcohol, cellulose acetate, organofluorine polymers, silicone polymers, etc., of which silicone polymers are the most suitable for the application of release agents.
Silicone mold release agent is the current rubber and plastic mold release agent in the mid-range market mainstream products, in polyurethane, rubber, polyethylene, and polyvinyl chloride resin processing are widely used. Silicone release agent is widely used in a variety of rubber, and plastic processing, can be used for extrusion, and injection processing, and can also be used for molded products molding.
2.2 According to dosage form
The dosage form of mold release agent is divided into two types: solid and liquid.
Solid form is the application of fine powdered materials, due to the inconvenience of the application of powdered substances, and may be transferred to attach to the surface of rubber and plastic products, rubber and plastic products in the processing of fewer applications.
Frequently used mold release agents' initial form is mostly liquid, with some applications of liquid body polymer, there are also effective body materials to add solvents, emulsifiers, fillers, and other components of the solution, emulsion, paste, but also by them and then add a projectile agent to produce aerosols and so on. Coated on the mold release agent is in the form of liquid film, and some are cured into a solid film.
2.3 According to application or process conditions
According to the specific processing materials or applications directly named mold release agent, for example, Polyurethane mold release agent, tire mold release agent, etc.
According to the actual use of the process, conditions called mold release agent are specially formulated, for example, high-temperature resistant mold release agent, and acid and alkali resistant release agent.
3. How to use silicone mold release agents?
Silicone mold-releasing agents include different forms, and a variety of dosage forms, which are suitable for different types of materials and different processing techniques. Therefore, it is necessary to select the most suitable mold release agent specially formulated according to the working temperature, the size of the peeling force, and the subsequent surface coating and bonding requirements of the product.
3.1 Rubber tire processing release agent
Rubber tire molding and processing of emulsion-type silicone release agent, the use of Methyl silicone oil or Phenylmethyl silicone oil, hydroxyl capped silicone oil, and a small number of silicone resin with an active reactive group (silicone hydroxyl) as the main polymer, with the appropriate amount of Alkoxysilane cross-linking agent and organostannic carboxylate catalysts, and then attached to the wetting agent, fungicide, and other additives, emulsification of the emulsion-type silicone mold release agent with water emulsification system, storage, and stability, good mold release effect, long service life. It has good storage stability, a good mold release effect, and a long service life. It can be used in pneumatic tires or semi-pneumatic tire molding process, the outer surface of the tire from the surface of the steel film peeling friction is low, and the inner surface of the tire and the airbag separation lubrication is good.
You can comprehensively use Methyl Chlorosilane monomer fractionation of high-boiling and low-boiling material preparation of silicone polymers, which can also achieve quite good results in the production of rubber and plastic products processed mold release agents.
3.2 Aerosol-type silicone mold release agent
Most of the silicone mold release spray using the appropriate viscosity of silicone oil as the main silicone polymer, with a wetting agent, ejector, and other components, sealed in a metal can with a spray device, snap the spray button, the silicone mold release spray was a fine droplet-like spray to the metal molds surface, ejector volatilization after the formation of the mold release agent work film. Aerosol silicone mold release spray is easy to use, mainly used in the molding of small-sized fine rubber and plastic parts and electronic components in plastic packaging.
Aerosol silicone mold release spray can be applied with different viscosity silicone oil mixing, which can improve the mold release effect, and increase the number of effective releases of each spray film. If you change to water-soluble polyether-modified silicone oil as the main component of the mold release spray, the silicone mold release agent does not affect the subsequent adhesive finishing performance of the molded product.
3.3 Aramid cloth mold supporting high-temperature silicone mold release agent
Aramid heat resistance can be up to 350 ℃, has high mechanical strength, aramid cloth as a mold hot compression molding wood fiberboard, and high production efficiency, which is currently the preferred advanced molding process of fiberboard. However aramid cloth's anti-adhesive performance is not good, most of the mold release agents have high-temperature performance, and aramid cloth does not match. If using an ordinary silicone resin base material mold release agent, although the heat resistance is still good, the general-purpose silicone resin cured film back to viscosity, can not play the role of mold release isolation.
You can apply special synthetic technology development and produce of high curing activity of methyl phenyl silicone resin, not only has the usual methyl phenyl silicone resin of high heat resistance, but also has a high curing activity, after curing the coating film and the substrate adhesion is firm and cured paint film never back to viscosity and other outstanding advantages. The high curing activity of methyl phenyl silicone resin coated with aramid cloth, heat curing, silicone resin coating film firmly attached to the aramid cloth, subjected to high-temperature molding for long-term operation, but still maintains excellent demolding properties.
3.4 High-temperature non-migratory silicone mold releasing agent for aerospace projects
In aerospace engineering applications of high-performance fiber composite molding processing at high temperatures, molded products are required to maintain reliable adhesive properties. Such composite materials molding processing mold release agent requirements are extremely demanding: in addition to the requirements of high molding accuracy of the parts, the product peeling force is small but also requires a mold release agent working temperature of 180 ℃ or more, and even the individual workpiece processing temperature of up to 400 ℃, and the same time requires that the mold release agent components shall not migrate to the parts, so as not to affect the subsequent bonding process.
Applying special composite silicone resin as the base polymer, with high-temperature wetting agent and composite solvents, can be made to fully meet the above demanding requirements of the silicone mold release agent. The coating leveling is good, and the coating film by 150 ℃ heating and curing, can be repeatedly used, and continue to maintain high-temperature non-migration of reliable mold release performance, which is widely used in a variety of aerospace engineering composite materials processing.
3.5 High-efficiency dip-coating anti-adhesive isolation agent
When applying liquid resin in impregnation encapsulation of electronic components, often encapsulation with liquid resin adhering to the metal lead is difficult to remove the problem: if the mechanical scraping method, not only low efficiency but also due to scratching the lead on the plating layer and affect the weldability of components; such as the use of commonly used release agent pre-coating of the metal lead, often due to the migration of the release agent, resulting in impregnation of encapsulation resin in the root of the lead. If the commonly used mold release agent is used to pre-coat the metal leads, the migration of the mold release agent often results in the impregnating resin at the root of the lead and the components cannot be marked after encapsulation.
You can apply low surface energy silicone polymers with high crosslinking degree curing agent components, and develop a highly efficient dip coating anti-adhesive barrier. When applying the isolating agent, you should roll coating in the appropriate part of the metal leads of electronic components, after curing, electronic components in the liquid epoxy resin submerged more than the isolating agent pre-coated lead parts, when the electronic components from the material bath, after the original attached to the pre-coated isolating agent lead parts of the epoxy resin will be automatically against the direction of gravity upward contraction to achieve the electronic components encapsulation of the tight full and the lead is not stained with resin, the resulting electronic components to maintain reliable solderability.
4. How to choose the silicone mold release agent raw material?
XJY-RA/XJY-RAN MQ Silicone Resin is formed by the polymerization of tetrafunctional siloxane (Q) and monofunctional methyl siloxane (M). It has good application efficacy in the field of high-temperature, semi-permanent, or permanent mold release agents.
Silicone mold release agents are specially formulated with high and low-temperature resistance, low surface tension, and no corrosion to metals. Adding silicone resin (5-15%) can significantly improve the strength of the silicone oil film, in the field of high-temperature castings, tire molding, automotive seat cushions, and other areas with good application results.
5. How to make silicone mold release agents better performance?
A high silicone content mold release agent has a good mold release effect, can effectively reduce the adhesion and friction between the silicone molds and the material, improves the service life of the silicone molds, and improves molding efficiency. Silicone mold releasing agent has good stability in high temperatures, high pressure, and other harsh conditions, not easy to decomposition reaction, to avoid the mold releasing agent in the mold surface residue, suitable for multiple part releases. Silicone mold releasing agent is an environmentally friendly mold release agent, that will not cause pollution to the environment, in the production process, and will not release any harmful substances. How to improve the competitiveness of your products specially formulated?
XJY Silicones is one of the leading silicone MQ resin and VMQ silicone manufacturers in China, with more than 30 years of R&D and manufacturing experience in the silicone industry as well as more than 15 related patents and technical support. Our silicone resins can meet the needs of silicone release agents and support the provision of diversified customized solutions.
