Cosmetics, as one of the pillar industries of fast-moving consumer goods, has become increasingly cognition and awareness among consumers. Consumers are no longer blindly following the trend, and are more concerned about the safety and health of cosmetics; along with the safety of cosmetic packaging materials More stringent requirements.
Incompatibility between cosmetics and content is also common in cosmetics companies, such as plastic bottle expansion, bottle body cracking, bottle body color precipitation and so on.
The compatibility of the packaging material broadly refers to the interaction between the packaging material and the content, including chemical compatibility, physical compatibility, and biocompatibility.
1. Chemical incompatibility
Chemical incompatibility simply means that the chemical components in the packaging material have a chemical reaction with certain ingredients in the content, which is manifested in the appearance of the packaging material or the content, changes in odor, and so on.
2. Biological incompatibility
Biological incompatibility refers to the migration of certain substances in cosmetic plastic packaging into cosmetics. For this judgment, the amount of harmful substances dissolved is directly used as the basis for judgment. And this is strictly regulated in the cosmetic hygiene regulations.
3. Physical incompatibility
Physical incompatibility refers to the physical changes between cosmetic packaging and contents due to mutual influence, such as cracking, dissolution, adsorption, penetration, and so on.
In summary, the numerous incompatibilities are usually not manifested in a single form. Why is it incompatible, and which raw materials are incompatible with which materials are particularly important.
Commonly used plastic packaging materials are: PE, PP, PET, PVC, ABS, etc.
(1) PE is not soluble in any organic solvents, but hydrocarbons and oils may cause PE swelling. The embrittlement temperature of PE is generally below -30 degrees. It has good cold resistance, small changes in mechanical properties at low temperatures, and excellent performance. Heat sealability, thermal adhesion, radiation resistance. PE is a non-polar polymer with poor printability, and its permeability to polar compounds is lower than that of non-polar compounds.
(2) PP has excellent mechanical properties. PP is a non-polar material with poor printing performance. Its tensile strength, hardness, wear resistance, heat resistance, and gas barrier properties are all higher than PE. PP has good bending fatigue resistance, and is often used to make various bottle caps or conjoined plastic boxes. PP has good chemical stability, can withstand acids, alkalis, salts and many organic solvents below 80 degrees, and does not cause stress cracking in many solvents, detergents and detergents. PP has poor aging resistance, poor cold resistance, and easy brittleness at low temperature. In cosmetic packaging, PP is mainly used to make various bottle caps, jars, droppers, etc.
(3) PVC resin is polymerized with polyvinyl chloride, and the thermal stability of PVC resin is poor. When it exceeds 150 degrees, it will degrade and release hydrogen chloride, and it will also degrade under 100 degrees for a long time. Thermal decomposition also occurs during plastic molding. In order to improve the thermal stability of PVC, some stabilizers must be added when making plastics; the viscous fluidization temperature of PVC is close to its decomposition temperature, and its fluidity is poor, so it will be added to plasticizing Agent to improve its processing and molding properties. The addition amount of the speed-increasing agent reaches 30%-40% of the resin amount to make soft PVC, and when the addition amount is less than 5%, it makes hard PVC; this is why we see that sometimes PVC is very soft, but Sometimes it will be hard. The higher the transparency of PVC, the better the barrier to oxygen. Rigid PVC has higher tensile strength and rigidity, while soft PVC has higher flexibility. PVC has good chemical stability, colorability, and printing adaptability. It can withstand most acids and alkalis at room temperature, and has good grease resistance. PVC resin itself is non-toxic, but the raw material vinyl chloride monomer is toxic, and the addition of plasticizers and stabilizers in the process will affect the hygiene and safety of PVC. Packaging made of PVC is mainly used for daily necessities, such as: shampoo, gel water, etc.
(4) PET is commonly known as polyester, PET has high transparency, good gloss, excellent gas barrier, oil barrier, hygiene and safety and fragrance retention properties. Rigid and tough, the tensile strength is 5-10 times that of PE. Good chemical stability, resistant to dilute acids, alkalis and common organic solvents. PET can maintain its excellent physical and mechanical properties in a wide temperature range. The normal use temperature range is -70 degrees to 120 degrees, and it can be used at 150 degrees for a period of time. PET composite film is widely used. Plastic bottles made of PET have high transparency, good gloss, high mechanical strength and chemical stability. Use PET bottles to hold colorful contents, which has a good shelf display effect.
(5) ABS resin has almost no effect on water, inorganic salts, alkalis and acids. It will dissolve or form emulsions in ketones, aldehydes, esters, and chlorinated hydrocarbons; it is insoluble in most alcohols and hydrocarbon solvents. However, it will soften and swell after prolonged contact with hydrocarbons. The corrosion of ABS resin surface by glacial alkyd, vegetable oil and other chemicals can also cause stress cracking, but it has little effect on non-stressed products.