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Mar 12, 2020
For non-chemical professionals, this term is too strange. Will it exist in our lives and is it closely related to life? The stickers, label paper, and even the back of the aunt ’s towel in our home are all Can not do without "organic silicone release agent". The following is a silicone manufacturer Xinjiayu to show you what is a silicone release agent.
Release agent, also known as anti-adhesive, is used between the substrate and the pressure-sensitive adhesive layer. Its main function is to protect the pressure-sensitive adhesive layer coated on the substrate to prevent the pressure-sensitive adhesive layer from being contaminated or sticky. Living with other items and failing.
Whether it's labels, baking paper, self-adhesive envelopes, or hygiene products, release coatings are the true heroes behind the entire paper industry. Without a release coating, many everyday applications involving pressure-sensitive adhesives would not exist.
1. Composition of silicone release agent
Silicone release agents generally include polymer base agents, cross-linking agents, catalysts, solvents, inhibitors, and additives. Polymer base agents are a major formulation material of release agents, which affect the release force and release force curve. , The stability and reactivity of the coating, but also affect the curing speed, bath life, adhesion and spreadability; cross-linking agents affect adhesion, bath life and curing speed; catalysts affect curing speed, bath life and stability Inhibitors affect curing speed, bath life, adhesion and paintability; additives such as heavy peel additives can produce higher release force, and affect adhesion, bath life and curing speed.
2. Characteristics of silicone release agent
Characteristics of silicone release agents
The characteristics of silicone release agents are mainly determined by the characteristics of the composition of the silicone polymer (silicone polymer). The surface energy of the silicone polymer is very low, and the critical surface tension γc is only in the range of 19 to 24 dyn / cm, and the release effect is good. Silicone polymers have good solvent properties in commonly used aromatic and aliphatic solvents. In addition, silicone polymers have low viscosity flow activation energy and good coating performance. They can be applied as extremely thin release coatings on substrates. Floor. After proper cross-linking of the silicone polymer, the cohesive strength of the silicone coating and its binding force with the substrate can be enhanced, and the migration of the coating to the pressure-sensitive adhesive layer can be reduced during use. Changing the crosslinking density of the polymer and the molecular weight between the crosslinking points can adjust the release effect of the silicone coating within a certain range, which allows the silicone release agent to adapt to different product requirements.
1. Composition of silicone release agent
Silicone release agents generally include polymer base agents, cross-linking agents, catalysts, solvents, inhibitors, and additives. Polymer base agents are a major formulation material of release agents, which affect the release force and release force curve. , The stability and reactivity of the coating, but also affect the curing speed, bath life, adhesion and spreadability; cross-linking agents affect adhesion, bath life and curing speed; catalysts affect curing speed, bath life and stability Inhibitors affect curing speed, bath life, adhesion and paintability; additives such as heavy peel additives can produce higher release force, and affect adhesion, bath life and curing speed.
2. Characteristics of silicone release agent
Characteristics of silicone release agents
The characteristics of silicone release agents are mainly determined by the characteristics of the composition of the silicone polymer (silicone polymer). The surface energy of the silicone polymer is very low, and the critical surface tension γc is only in the range of 19 to 24 dyn / cm, and the release effect is good. Silicone polymers have good solvent properties in commonly used aromatic and aliphatic solvents. In addition, silicone polymers have low viscosity flow activation energy and good coating performance. They can be applied as extremely thin release coatings on substrates. Floor. After proper cross-linking of the silicone polymer, the cohesive strength of the silicone coating and its binding force with the substrate can be enhanced, and the migration of the coating to the pressure-sensitive adhesive layer can be reduced during use. Changing the crosslinking density of the polymer and the molecular weight between the crosslinking points can adjust the release effect of the silicone coating within a certain range, which allows the silicone release agent to adapt to different product requirements.
According to the different cross-linking systems, it can be divided into two types: condensation and addition.
Condensation type silicone release agent
Condensing silicone release agents were first industrialized in 1954. The real catalyst in the condensation silicone release agent is dibutyltin. With the EU ’s restriction on dibutyltin and dioctyltin compounds 2009/425 / EC came into effect on January 1, 2012, its future contact with the human body, food, etc. Release coating applications are limited.
Additive silicone release agent
Additive silicone release agents were first applied industrially in 1975. Mainly, dimethyl polysiloxane with vinyl group was subjected to hydrosilylation reaction with a silicon-hydrogen-containing crosslinking agent catalyzed by a metal platinum compound. The cross-linking is cured. Compared with condensation type, the addition of silicone release agent has many advantages: ① easy molecular design, that is, easy to adjust and control the molecular weight and crosslinking degree of the polymer, so as to obtain the desired release effect; ② suitable for preparation Solvent-free, emulsion-type release agents. These two types of release agents represent future trends; ③ cross-linking will not occur during storage and transportation, and product quality is easily guaranteed.