Carbomer (carbomer) is a kind of acrylic crosslinking resin which is crosslinked with acrylic acid by pentaerythritol and so on. It is a very important rheological regulator. After neutralization, Carbomer is an excellent gel matrix with thickening, suspension and other important uses. Its technology is simple and its stability is good. It is widely used in emulsion, cream and gel. Although there will be a simple text description on the introduction of each raw material, how much do you know about the full knowledge of carbomer? As a manufacturer of Carbomer, Desheng summarizes the product knowledge of carbomer.
essential information
Name: Carbomer, polyacrylic acid; carboxyl ethylene copolymer
Appearance: white powder
Solubility: soluble in water, 0.2% 940 soluble in water, white translucent liquid, add triethanolamine or sodium hydroxide to dissolve
The liquid was colorless, transparent and sticky gel.
Thermal stability: swelling in water, generally at 80 ℃ - 85 ℃
Photostability: carbomer neutralized with triethanolamine or sodium hydroxide solution is easy to dilute under long-term natural light
Determination method
Method name: Determination of carbomer potentiometric titration
Scope of application: this method uses potentiometric titration to determine the content of carbomer.
Method principle: the test sample was dissolved in water, titrated with sodium hydroxide titrant according to potentiometric titration method, and the carbomer content was calculated.
Reagents: 1. Water; 2. Sodium hydroxide titrant (0.25 mol / L); 3. Standard potassium hydrogen phthalate
Operation steps: take about 0.4g of this product, accurately weigh it, evenly disperse it in 400ml water, stir to dissolve it, titrate with sodium hydroxide titrant (0.25mol/l) according to potentiometric titration method (when it is near the end point, stir at least 2 minutes after each drop). Every 1 ml sodium hydroxide titrant (0.25 mol / L) is equivalent to 11.25 Mg - COOH.
Thickening method
1. Neutralization thickening
Sodium hydroxide and triethanolamine are commonly used as neutralizers, which is the reason why carbomer is sensitive to ions.
2. Hydrogen bond thickening
Carbomer molecule as carboxyl donor can combine with one or more hydroxyl groups to form hydrogen bond and thicken. This neutralization method takes time. The commonly used hydroxyl donors are nonionic surfactants, polyols and so on.
Configuration taboo
1. Carbomer discolors with m-diphenol and is incompatible with phenol, cationic polymer, strong acid and high concentration electrolyte. Some antimicrobial agents should also be avoided or used in low concentration. Trace amounts of iron or other transition metals can catalyze the degradation of carbomer dispersions. When carbomer comes into contact with strong alkali substances such as ammonia, sodium hydroxide, potassium hydroxide or strong basic organic amines, a large amount of heat can be generated.
2. Some drugs with amino functional groups can form water-soluble complexes with carbomer. Usually, this situation can be prevented by adjusting the solubility parameters of liquid with appropriate alcohol or polyol.
3. Carbomer can also form pH dependent complexes with some polymer excipients, and adjust the solubility parameters, which can also play a role in this condition.
susceptibility
1. Mechanical shear after carbomer neutralization, long-term stirring or high shear stirring will cause viscosity loss
2. The presence of ions - electrolytes reduce thickening efficiency
3. UV - long term ultraviolet irradiation will make the carbomer gel less sensitive to ultraviolet radiation when its viscosity is reduced by pH>/=10.
4. temperature change carbomer gel is not affected by temperature.
5. microorganism carbomer does not support the growth of bacterial mold, and the growth of bacterial mold does not affect the gel properties. The conventional dosage is 0.2-0.4%, which can replace 3-7% of conventional emulsifier. Carbomer polymer has almost no properties of surfactant, so adding 0.1-0.5% low HLB surfactant can adjust the oil phase particles to be smaller, so as to prepare white and delicate cream products.
purpose
1. Emulsifier
(1) It is effective at very low concentration of 0.1-0.5%, replacing the traditional surfactant dosage of 3-7%;
(2) It is not limited by HLB and PLT;
(3) It can emulsify any liquid oil at room temperature;
(4) If the wax is melted in the manufacturing process, it can be emulsified;
(5) The stable emulsions can be prepared by making full use of the wetting, dispersing and adhering functions of surfactants;
(6) When rewetting, it will not emulsify again, so it is easy to prepare waterproof emulsion without film-forming agent;
(7) High oil phase can be dissolved into water to form (O / W) emulsion;
(8) can be prepared: moisturizing cream, lotion, cleansing products, sunscreen products, alcohol free perfume, flavor conditioner (enhanced gloss, easy to comb), hand washing agents, low consistency spray emulsion and transparent microemulsion.
2. Used in skin care products
Hydrophilic thickener, stable emulsifier, suspending agent and gel have good transparency. It is necessary to maintain moderate to weak alkalinity to have consistency. Therefore, it is impossible to coexist with acid active ingredients. In addition, Carbomer is also afraid of salts. Therefore, mineral ions can not be added, otherwise the consistency will disappear and irritation to the eye mucosa.
