Metal soap heat stabilizers

Metal soap heat stabilizers narrative theory and literature very much, this article highlights only some of the most easily accepted to be introduced. As it relates to compatibility with the majority of the  plastic flame retardant metal soap heat stabilizers are not suitable for rigid PVC products. Soft PVC products contain a significant proportion of plasticizer, thereby PVC resin solubility parameter range becomes wide, metal soap heat stabilizers play space increases, so the metal soap heat stabilizers in the market mostly focused on soft or semi-rigid PVC products.
Metal soap heat stabilizers heat agencies
Hydrochloric acid or free chlorine atoms caused by both the decomposition of PVC resin starting material, in principle, as long as the source of HCl cut decomposition of PVC resin can be prevented. Metal soaps (Metal Soap) basic role is to pyrolysis of PVC resin in the release of hydrochloric acid or free chlorine atoms immediately be absorbed, and finally then transferred into harmless metal chlorides. Called "harmless metal chlorides," theoretically no longer continue the catalytic decomposition of PVC resin capacity. Metal soap is a metal part of the capture hydrochloric acid or free chlorine, hydrogen radical part of the acceptance; capture hydrogen chloride and receive capability must be some balance. After absorption of hydrochloric acid metal soap will be converted into metal chlorides, however, some of the metal chloride in PVC resin accumulated to a certain concentration, the still enough to endanger PVC resin. At this point a second metal soap harmful to metal chlorides manner by chemical reactions consumed, and then into another harmless metal chloride.
To meet the above requirements, the recipe must be merged within the two metals usually soap. The first stage is chemically immediate and effective absorption of hydrochloric acid, macroscopic manifestation is excellent early color. The second stage is formed after the absorption of hydrochloric acid metal chloride into harmless non-acidic or metal chloride, this step refers to a final desired coloring.
Although the first metal soap formed after absorption of HCl may still acidic metal chloride, PVC resin, or will continue to catalytic decomposition. However, selecting the first one metallic soap still tend to focus only when the "immediate and effective absorption of HCl," so the first PVC resin, a metal soap in the ability to be absorbed very strong acid. The second metal soap in function stress "will be accumulated consumed metal chloride or exclusion", so choose the time of the second metal soap must focus on whether or not it has a strong tendency and metal chlorides react. The use of a second metal soap acidic metal chlorides into no acidic metal chloride, and finally achieve full protection PVC resin effect.
Heat resistant metal soap stabilizer mechanism may briefly expressed as follows:
A first metallic soap + HCl → a first fatty acid metal chloride +
A first metal chloride + second metal soaps
→ first metal soap of a second metal chloride +
In the earliest cadmium stearate, barium stearate powder stabilizers, for example, to play a chemical reaction heat function is as follows. Powder barium cadmium heat stabilizer chemical reactions are involved.
Cd (C17H35COO) 2 + 2HCl → CdCl2 + 2C17H35COOH
(Cadmium stearate) (hydrochloric acid) (cadmium chloride) (stearic acid)
Ba (C17H35COO) 2 + CdCl2 → BaCl2 + Cd (C17H35COO) 2
(Barium stearate) (cadmium chloride) (barium chloride) (cadmium stearate)
Question: Why does not directly or barium stearate alone?
Metal chlorides species very much, but in the field of thermal stabilizers, zinc, cadmium, antimony and aluminum chloride (e.g., zinc chloride, cadmium chloride, etc.) or a strong acid itself, will still be catalyzed PVC resin continuation of decomposition. The barium and calcium chloride because it is not acidic, so even if the concentration is not accumulated to a considerable extent induce deterioration of PVC resin. In other words, PVC resin accumulated too much if the zinc chloride or cadmium chloride, will accelerate the decomposition of PVC resin; if barium or calcium accumulated in the PVC resin has no effect.
If the recipe is only within the  tribasic lead sulphate cadmium or zinc stearate, stearic acid, even if the initial processing will have a good effect of heat, can be expected to post machining heat effect is not ideal. Only within the formula barium stearate, it is a final coloring is very good, but not good initial coloring. Individual hot metal soap stabilizers single product, the heat effect is very poor, so commercial heat stabilizer metallic soap must be at least a combination of two or more metal soaps.
The characteristics of a single product metal soap
Barium soaps are very polar metallic soap a thermal stabilizer, its heat resistance is very good. A high melting point of barium soap, the processing temperature is not enough to melt most of the barium complex soap. Hot liquid barium zinc stabilizer, and barium zinc cadmium heat stabilizer composition is very complex, difficult soluble barium soaps wherein a metallic soap. Barium soap following features:
Final color is very good, but dibutyl phthalate  not exceptional initial coloring.
No UV protection, it does not have a weather resistance.
Add excessive, machine surface precipitation trend stronger; fact precipitated barium soap machine surface phenomena are all metal soaps in the most obvious.
Suitable for use with all types of metal soaps, play synergistic effect.
Hard or soft machining are no problem.
Cadmium soap gelling properties of exceptional merit, is the most traditional one metal soap heat stabilizers. Cadmium soap that require transparency and weather resistance on soft PVC products.