Cosmetic plastic tubes are generally made of vinyl chloride monomer, which is polymerised by peroxide, azo compounds and other initiators or by free radical polymerisation reaction mechanisms under the action of light and heat. Vinyl chloride homopolymers and vinyl chloride copolymers are collectively called vinyl chloride resins. PVC is a non-crystalline material to which stabilisers, lubricants, auxiliary process agents, colours, impact agents and other additives are often added in practice. It has non-flammability, high strength, resistance to weathering and excellent geometric stability.
PVC is highly resistant to oxidising agents, reducing agents and strong acids. However, it can be corroded by concentrated oxidising acids such as sulphuric acid and nitric acid and is not suitable for contact with aromatic and chlorinated hydrocarbons.
The choice of plastic cosmetic tube:
A. Hygiene of plastic cosmetic tube materials
First of all, the materials used should meet the relevant health standards, heavy metals, fluorescent agents and other harmful substances should be controlled within the prescribed limits. For example, the tube exported to the United States, the polyethylene (PE), polypropylene (PP) used to meet the U.S. Food and Drug Administration (FDA) standards 21CFR117.1520.
B. Barrier properties of plastic cosmetic tube materials
If the contents of the daily chemical enterprise packaging is some of the oxygen is particularly sensitive (such as some whitening cosmetics) or fragrance is very easy to volatile (such as essential oils or some oils, acids, salts and other corrosive chemicals) of the product, this should be selected with five layers of co-extruded tube. The oxygen transmission rate of a five-layer co-extruded tube (polyethylene/binder resin/EVOH/binder resin/polyethylene) is 0.2 to 1.2 units.
The oxygen transmission rate of an ordinary polyethylene single-layer tube is 150 to 300 units. In a given period of time, the weight loss rate of the coextruded tube is tested to be tens of times lower than that of the monolayer tube. In addition, EVOH is an ethylene - vinyl alcohol copolymer, has excellent barrier, fragrance preservation (thickness in 15 ~ 20 micron effect is most ideal) double-layer tube: the use of high-density HDPE and LDPE low-density PE material, in a certain proportion with the pumping method, with high-speed rotation to achieve uniform mixing effect, this way can be properly adjusted tube The softness and hardness of the tube, compared to the single-layer tube, the tube body is thicker, there is better corrosion resistance barrier, lower oxygen transmission rate, by the majority of daily cosmetics manufacturers to use.
C.cosmetic plastic tube material stiffness
Daily chemical companies have different requirements for the stiffness of the tube, so how to get the desired stiffness? Commonly used in the tube of polyethylene to low density polyethylene, high density polyethylene, linear low density polyethylene. The stiffness of high-density polyethylene is better than low-density polyethylene, so by adjusting the ratio of high-density polyethylene/low-density polyethylene can achieve the desired stiffness.
D. Chemical resistance of cosmetic plastic tube materials
High-density polyethylene has better chemical resistance than low-density polyethylene.
E. Weather resistance of plastic cosmetic tube materials
To control the short-term or long-term performance of the tube, factors such as appearance, pressure/drop resistance, seal strength, environmental stress cracking resistance (ESCR value), fragrance and loss of active ingredients need to be considered.
How to identify the raw materials of cosmetic plastic tubes?
1. Cosmetic plastic tube PP=== Pepto-Bismol, polypropylene
Light and tough, easy to process, good heat resistance,. High impact strength at room temperature, high tensile strength, good rigidity, corrosion, difficult to paint, folding resistance up to millions of times, excellent electrical properties, shrinkage rate. pp. pe. pa soft and bendable, hard wax-like to the touch, slippery feeling, knocking with soft horny sound, and ps. abs. pc. pmma, no ductility, knocking with a crisper sound. pp burning phenomenon is largely the same as pe, there may be a small amount of black annihilation. After the flame is extinguished, the smell is between paraffin and other petroleum smell, non-toxic.
2., cosmetics plastic tube LDPE=== soft rubber, high pressure low density polyethylene
HDPE=== hard soft rubber, low pressure high density polyethylene
VHDPE=== super hard soft rubber, super high pressure polyethylene
Light and tough. Easy to process, good heat resistance, low temperature toughness is good hard impervious to water, but good abrasive, PE flammable, away from the fire can still burn, burning flame on the yellow under the blue, black annihilation rarely, in the near flame, plastic has molten drip phenomenon, similar to the flow of candles, after the flame is extinguished, there is a more obvious smell of paraffin burning, non-toxic PE. pp specific gravity are less than water, floating in water. The vast majority of other plastic specific gravity greater than water, sinking in water.
3., cosmetic plastic tube PC=== bulletproof rubber, polycarbonate
Colorless transparent, impact strength for the first plastic, excellent electrical properties, anti-aging, shrinkage rate is small, product size stability, PC burning phenomenon close to PS but slow burning speed, away from the fire will be slow to extinguish, the flame is yellow, with black annihilation charcoal bundle, burning molten blistering, extinguished hair is flower and fruit stink.
4. Cosmetic plastic tube PMMA=== Plexiglas (Acrylic)
Polymethyl methacrylate transparency is very good, can be dyed into a variety of colours, brittle and easy to crack, the surface hardness is poor, easy to rub flowers. PMMA and PS original colour are transparent, but the burning situation is different, PMMA no charcoal beam fly, while PS is there, PMMA burning flame is light blue, white at the top, burning melt blister, issued a strong flower and fruit odor and rotten vegetable odor, emblematic poison.
5. cosmetics plastic tube PS=== hard rubber (ordinary hard rubber), polystyrene, transparent and easy to brittle crack
HIPS=== not broken rubber, modified polystyrene, elastic. Toughness and get high impact strength
ABS=== ABS adhesive,. Super unbreakable adhesive, acrylonitrile-butadiene-styrene, easy to plating. High strength. Resistant to impact, cold, abrasion and corrosion.
SAN (AS)=== Transparent non-shattering adhesive, styrene-acrylonitrile copolymer
EPS=== Styrofoam, expanded polystyrene
PS original colour is transparent, HIPS original colour is milky white, ABS original colour is light ivory.
The main difference between PS, HIPS and ABS is that PS is more brittle and HIPS and ABS are more resilient. PS. HIPS. and ABS are flammable, and can still be renewed after removing the fire source, the flame is yellow, and there is a thick black annihilation charcoal bundle, with the annihilation gas escape, PS charcoal bundle is slightly less, burning, near the flame at the surface of the plastic softened When burning, the surface of the plastic near the flame softens and does not drip easily, PS and HIPS surface will blister, ABS does not blister and is scorched state, these plastics in the extinguishment of the odour issued by the great difference, PS with styrene monomer smell, ABS issued a pungent smell, there is a certain degree of toxicity.
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