Some Knowledge of Release Agent

Nov 9, 2020

Release agent is a functional substance between the mold and the finished product. The release agent is chemically resistant and will not be dissolved when it comes in contact with the chemical components of different resins (especially styrene and amines). The release agent also has heat resistance and stress properties, and is not easy to decompose or wear; the release agent adheres to the mold and does not transfer to the processed part, and does not interfere with painting or other secondary processing operations. Due to the rapid development of injection molding, extrusion, calendering, molding, laminating and other processes, the amount of release agent is also greatly increased.

The release agent is an interface coating used on the surface of two objects that are easy to adhere to each other. It can make the surface of the object easy to peel off, smooth and clean. Mold release agents are used in various molding operations such as glass fiber reinforced plastics, metal die-casting, polyurethane foam and elastomers, injection molded thermoplastics, vacuum foamed sheets and extruded profiles. During molding, sometimes other plastic additives such as plasticizers will ooze out to the interface. At this time, a surface remover is needed to remove it.

Theoretically, the release agent should have a large tensile strength, so that it is not easy to polish when it is in frequent contact with the molded resin. This is especially true when there are frosted mineral fillers or glass fiber reinforcements in the resin. The release agent should have chemical resistance so that it will not be dissolved when it comes in contact with the chemical components of different resins (especially styrene and amines). The release agent should also have heat resistance and stress properties, not easy to decompose or wear; the release agent should be bonded to the mold and not transferred to the processed parts, so as not to interfere with painting or other secondary processing operations.
Type use
1. Classified by usage: internal release agent, external release agent; 　
2. Classification by life: conventional release agent, semi-permanent release agent; 　
3. Classified by form: solvent-based release agent, water-based release agent, solvent-free release agent, powder release agent, paste release agent
4. Classified by active substance: 　

①Silicon series-mainly silicone compound, silicone oil, silicone resin methyl branched silicone oil, methyl silicone oil, emulsified methyl silicone oil, hydrogen-containing methyl silicone oil, silicone grease, silicone resin, silicone rubber, silicone rubber toluene solution　
②Wax series-plant, animal, synthetic paraffin; microcrystalline paraffin; polyethylene wax, etc.　
③Fluorine series-the best isolation performance, less pollution to the mold, but high cost PTFE; fluorine resin powder; fluorine resin coating, etc.
④Surfactant series-metal soap (anionic), EO, PO derivatives (non-ionic)
⑤Inorganic powder series-talc, mica, clay, white clay, etc.
⑥Polyether series-a mixture of polyether and fat oil, which has good heat resistance and chemical resistance, and is mostly used in certain rubber industries that have restrictions on silicone oil. The cost is higher than the silicone oil series.

Other water-containing mold release agents containing masking agent: use masking agent to fix water molecules Durable mold release agent: silicone oil + silicone resin system, more than 800 times multilayer composite mold release agent: halogenated hydrocarbon film + polyethylene mold release agent + Polyvinyl alcohol mold release agent, aromatic polysulfone mold release agent, mold release agent, halogen-containing polyether mold release agent: reduce vapor pressure, increase decomposition temperature, and will not cause charged contact with carbonyl alkyl silane mold release agent: Internal mold release to improve the adhesion to the surface of water-based ink. Reactive mold release agent: After coating, it chemically reacts to form a film and adheres to the mold surface. The above are some representative mold release agents, which have their own characteristics. And can be used separately according to purpose. For example, it is used as a back surface treatment agent for fiber adhesive tape, release paper, anti-sticking agent (telephone poles, telephone boxes, signs, signs), and pollution prevention (internal and external wall coating, vehicles, roadblocks, road fences, etc.) Residual stick around the adhesive.

Main features of this paragraph
①Releasability (lubricity). When forming a uniform film with a complex shape, the size is accurate.　
② Good continuity of demoulding.　
③The appearance of the molded product is smooth and beautiful, and it will not cause dust adhesion due to the sticky release agent.　
④ Superior secondary processing. When the release agent is transferred to the molded object, it has no adverse effects on the processed objects such as electroplating, hot stamping, printing, coating, and bonding.　
⑤Easy to coat.　
⑥ Heat resistance.　
⑦ Pollution resistance.　
⑧Good forming and high production efficiency.　
⑨Good stability. When used with compounding agents and materials, its physical and chemical properties are stable.　
⑩ Non-combustibility, low odor and low toxicity.

Basic performance of this paragraph
Theoretically, the release agent should have a large tensile strength, so that it is not easy to polish when it is in frequent contact with the molded resin. This is especially true when there are frosted mineral fillers or glass fiber reinforcements in the resin. The release agent should have chemical resistance so that it will not be dissolved when it comes into contact with the chemical components of different resins (especially styrene and amines). The release agent should also have heat resistance and stress properties, not easy to decompose or wear; the release agent should be bonded to the mold and not transferred to the processed parts, so as not to hinder painting or other secondary processing operations.

Advantages of editing this paragraph
●Ultra-fine jetting makes the entire mold completely covered;
●Improve the finish and reduce the risk of overspraying;
●Reduce related problems caused by marking and transportation, fast and effective;
●The demoulding is very economical, and it can be demoulded many times with only one spraying;
●High-efficiency and long-lasting lubricating film can provide multiple releases, which is better than other silicone formula products;
●It has little impact on the environment and does not contain CFC’s propellant.

Collapse edit this paragraph of chemical principles
1. The polar chemical bond interacts with the mold surface to form a regenerative adsorption film; 　
2. The silicon-oxygen bond in polysiloxane can be regarded as a weak dipole (Si+-O-). When the release agent is spread on the surface of the mold into a single orientation arrangement, the molecule adopts a unique extended chain configuration; 　
3. The free surface is covered by alkyl groups in a densely packed manner, and the demoulding ability increases with the density of alkyl groups; but when the alkyl groups occupy
When the steric hindrance is large, the stretching configuration is restricted, and the demolding ability will be reduced; 　
4. The molecular weight and viscosity of the release agent are also related to the release ability. The molecular weight is small and the spreadability is good, but the heat resistance ability