Cosmetic Packaging Resins
The information presented here is provided as a general guide for many of the
resin types available. This guide is not intended, nor should it be used, as the
selection criteria for your application. Each application should be evaluated by
a well-qualified engineer and tested to ensure that the product is compatible
with the container. Roberts Container makes no claim or warranty as to the
completeness or accuracy of the information provided.
There are many resins available for cosmetic packaging applications. Resins are
selected based on compatibility with the product formulation, appearance, cost,
moisture transmission rate, pigmentation, light or oxygen transmission, molding
properties, environmental considerations as well as governmental regulatory
requirements.
Selecting the correct resin for an application is an important consideration and
requires an understanding of the chemical properties of what goes into the
package (the product) along with the characteristics of the resin(s) selected
for the application.
Acrylonitrile Butadiene Styrene (ABS)
ABS is an ideal material wherever superlative surface quality, colorfastness and
luster are desired. ABS is a two-phase polymer blend. A continuous phase of
styrene-acrylonitrile copolymer (SAN) gives the materials rigidity, hardness and
heat resistance. The toughness of ABS is the result of sub-microscopically fine
polybutadiene rubber particles uniformly distributed in the SAN matrix.
ABS standard grades have been developed specifically to meet the requirements of
major customers in the cosmetic market. ABS is readily modified both by the
addition of additives and by variation of the ratio of the three monomers
Acrylonitrile, Butadiene and Styrene: hence grades available include high and
medium impact, high heat resistance, and ABS can be electroplated. Fiber
reinforcement can be incorporated to increase stiffness and dimensional
stability. ABS is readily blended or alloyed with other polymers further
increasing the range of properties available. The natural material is an opaque
ivory color and is readily colored with pigments or dyes. Transparent grades are
also available for different applications, the material is typically injection
molded or extruded.
Barex (AN)
British Petroleum, the world's largest producer of acrylonitrile, a co-monomer
that imparts high barrier to gases such as oxygen, aromas and fragrances as well
as chemical resistance and inertness, developed Barex Resins. Barex belongs to a
family of acrylonitrile-methyl acrylate copolymers grafted onto a nitrile
rubber. Several grades, in natural or blue tint, are available for a variety of
processes and applications. The chemistry behind Barex Resins makes them readily
convertible into film, sheet, and bottles on standard equipment using extrusion,
injection, calendering, and molding techniques. Whether thermoforming sheet,
stretching bottles, or engineering applications, products made with Barex Resins
offer uniform thickness, top to bottom. Introduced commercially in 1975, Barex
Resins initially found widespread use in packaging processed meat, correction
fluid, gasoline additives and agrochemicals. Since then, their use has expanded
to an ever-widening range of challenging packaging applications such as medical
and pharmaceutical products, personal care products, cosmetics and hair
coloring.
Ethylene Vinyl Acetate (EVA)
Ethylene Copolymers are leading materials for formulating hot-melts (pressure
sensitive and non pressure sensitive) in applications for the cosmetic packaging
market. Good resistance to water, salt and other environments can be obtained
but solvent resistance decreases with increasing vinyl acetate content. The
copolymers can accept high filler and pigment loadings. Extrusion, injection,
blow molding, calendering and rotational molding can be employed to form
thermoplastic EVA.
Low Density Polyethylene (LDPE)
LDPE has high impact strength with excellent environmental stress crack
resistance. With its low water and alcohol permeability and resistance to many
chemicals it is an ideal choice for applications in the cosmetic area.
Squeezability is good, especially in the low-density grade of this thermoplastic
material. It also displays better resistance to impact than the high-density
grade.
LDPE is similar to HDPE in composition. It is less rigid and generally less
chemically resistant than HDPE, but is more translucent. LDPE is used primarily
for squeeze applications including lotions and creams. LDPE is significantly
more expensive than HDPE, but will yield a glossy bottle when produced in
colors. The most common household use of LDPE is in plastic bags.
Medium Density Polyethylene (MDPE)
MDPE provides intermediate properties between low- and high- density
polyethylene. Bottles are less translucent than LDPE. Being flexible it is used
for squeeze containers, where more rigidity than LDPE and less rigidity than
HDPE is required. Like LDPE, MDPE is glossy when produced in colors. It is
commonly used for inexpensive consumer products.
High Density Polyethylene (HDPE)
HDPE is more rigid than LDPE and MDPE depending on density is a flexible resin
with an appearance that is wax-like, lusterless and has a natural milky color.
It is the high-density version of PE plastic. It is harder, stronger and a
little heavier than LDPE, but less ductile. It has good impact strength and is
resistant to environmental stress cracking. HDPE has better barrier properties
than LDPE and is easy to add color to.
HDPE is the most widely used resin for plastic bottles. This material provides a
good moisture barrier, is economical, impact resistant and compatible with a
wide range of products (including acids and caustics). It is usually supplied in
FDA approved food grade. When fluorine treated, HDPE becomes an effective
package for solvents (aromatic hydrocarbons) and oxygen sensitive extracts. The
addition of color will make HDPE opaque although not glossy. HDPE is supplied
surface-treated on a stock basis and lends itself readily to silkscreen
decoration. While HDPE provides very good protection at temperatures below
freezing, it cannot be used with products filled at over 180F or products
requiring a hermetic seal. Outside of the cosmetic industry the most common use
of HDPE is in containers for milk, liquid laundry detergent, etc.
Polycarbonate (PC)
Polycarbonate plastic is a lightweight, high-performance plastic with properties
including strength, lightness, durability, high transparency, heat resistance
and is easily processed. Hence, it is found in a number of products including
bottles and packaging, medical devices, electronics equipment, computer
housings, cars, building and construction applications as well as consumer
goods. It is also extensively used in optical data storage applications (e.g.
CDs, DVDs), safety equipment and lightweight, transparent roofing in building &
construction.
Polycarbonate properties:
- High transparency
- High strength making it resistant to impact and fracture
- High heat resistance, making it ideal for applications that require
sterilization
- Good dimensional stability - retain its shape in a range of conditions
- Good electrical insulation properties
- Biologically inert
- Readily recyclable
- Excellent processability
- Cost effective
Polyethylene (PE)
Polyethylene is probably the polymer you see most in daily life and is the most
popular plastic in the world. PE is used to produce cosmetic containers, grocery
bags, shampoo bottles, children's toys, and even bulletproof vests.
Polyethylene is classified according to their density, which in turn depends on
the extent and type of formulation.
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LLDPE (linear low density PE) - Used for tubing applications
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LDPE (low density PE)
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MDPE (medium density PE)
-
HDPE (high density PE
Polyethylene Terephthalate (PET) PolyesterPET is a rigid naturally crystal clear resin with fair water barrier properties.
It provides good oil, alcohol and solvent barrier properties. PET is one of
several resins in the polyester family. Bottles made from PET are injection blow
molded, un-oriented or injection stretch blow molded, biaxial oriented. PET
bottles have outstanding clarity, good impact and scratch resistance, high gloss
finish and good barrier properties. Containers manufactured with PET resin are
ideal for packaging a wide range of food products, toiletries, cosmetics and
household and pharmaceutical items. PET has taken global markets by storm as the
material of choice for beverage bottles. They are lightweight and safe compared
to glass (no breakage on filling lines, in transit, retail stores and in homes).
Last year alone (2004) 4.5 billion pounds of virgin thermoplastic polyester
resin was produced in the U.S.
Superior functional properties of PET include:
- Transparency
- Lightweight
- Chemical and mechanical resistance
- Protective barrier
- 100% recyclable
Glycol Modified Polyethylene Terephthalate (PETG) CopolyesterPETG is a modified member of the PET family. It is well suited to being
extrusion blow moldable with transparency better than PET particularly in thick
sections. It has fair water, alcohol and solvent barrier properties along with
very good oil barrier properties. It is a durable material with excellent gloss,
clarity and sparkle desired for clear bottles. PETG can be processed via
conventional extrusion blow molding methods, generally on machines designed to
process PVC.
Applications include shampoos, soaps, and detergents. PETG exhibits a good
impact strength and gas barrier. The chemical resistance of PETG is fair and
compatibility testing is recommended, especially with products that contain
alcohol.
Polymethyl Methacrylate (PMMA)
Polymethyl Methacrylate (PMMA), more commonly known by the generic name acrylic
and is polymerized from the hydrocarbon compound Methyl Methacrylate. PMMA is a
hard material and is extremely clear because of the amorphous arrangement of its
molecules. As a result, this thermoplastic is used to make high quality
compacts, pots and jars. PMMA products are marketed under familiar trade names,
including Plexiglas, Lucite, and Acrylite. Because PMMA can be cast to resemble
marble, it is also used to create some very interesting finishes. It is
generally considered to be a high-end resin and is an excellent choice for
premium products.
Polypropylene (PP)Polypropylene is a very versatile polymer. Structurally, it is a vinyl polymer,
and is similar to polyethylene, only that on every other carbon atom in the
backbone chain has a methyl group attached to it. Polypropylene is a naturally
translucent material, which provides contact clarity and an excellent moisture
barrier. One major advantage of polypropylene is its stability at high
temperatures (maximum temperature is 230 to 260F) and offers the potential for
steam sterilization. Polypropylene's compatibility with high filling
temperatures is makes it ideally suited for use with hot fill products.
Polypropylene has excellent chemical resistance making it widely suited for a
variety of applications. When manufactured with color, Polypropylene exhibits a
glossy finish. Clear Polypropylene film is also available and is used in
applications requiring flexibility and high barrier characteristics.
Polystyrene (PS)
Polystyrene may be best known as the resin used to produce foam coffee cups. For
cosmetic packaging applications it is commonly used to make low-end compacts for
the mass market.
Polystyrene is found in your home, office and in the cafeteria. It comes in many
shapes and forms, from foam egg cartons, meat trays, soup bowls, salad boxes,
and coffee cups to utensils and CD "jewel boxes." Styrene does not provide good
barrier properties and exhibits poor impact resistance. It can be screen printed
without being flame treated and lends itself well to offset printing.
Polyurethane (PU)
The origin of polyurethane dates back to the beginning of World War II where it
is was first developed as a replacement for rubber. The versatility of this
exciting new organic polymer and its ability to substitute for scarce materials,
spurred numerous applications. During World War II, polyurethane coatings were
used for the impregnation of paper and the manufacture of mustard gas resistant
garments, high-gloss airplane finishes and chemical and corrosion resistant
coatings to protect metal, wood and masonry.
Polyvinylchloride (PVC)Polyvinylchloride (PVC) was first produced commercially in the United States in
1933. It is one of the three most important polymers currently used worldwide
and has a large range of properties used to make hundreds of products.
Although a somewhat controversial resin, from an environmental standpoint, it
remains the 2nd most highly used resin throughout the world with over 20 million
tons produced annually. PVC is naturally clear, has extremely good resistance to
oils and very low oxygen transmission. It provides an excellent barrier to most
gases, but is vulnerable to certain solvents. PVC is a semi-rigid material
which, when produced on extrusion blow-molding equipment, can accommodate
"handled" designs. Improvements in resin formulation have increased oxygen
barrier properties and chemical resistance, along with a 20-30% improvement in
drop impact resistance. PVC exhibits good low temperature resistance but will
distort at 160F. It is not compatible with hot filled products. Because it
provides a good oxygen barrier, PVC is an excellent choice for salad oil,
mineral oil, and vinegar. It is also commonly used for shampoos, hair coloring
and cosmetic products.
Styrene Acrilonitrile (SAN)SAN's brilliant surface has great depth of color make it ideally suited for
cosmetic and personal care products. It looks good and feels good - an important
consideration in the cosmetic industry. SAN accepts print very easily and
affords diverse design possibilities. Moreover, SAN is resistant to chemicals.
It is rigid, transparent, and tough. It resists stress cracking and crazing and
is easily processed. SAN is a resin of choice for many Jars and Compacts.
Names & Abbreviations
ABS - Acrylonitrile Butadiene Styrene.
AN - Acrylonitrile - Barex.
EVA - Ethylene Vinyl Acetate.
HDPE - High Density Polyethylene.
LDPE - Low Density Polyethylene.
MDPE - Medium Density Polyethylene.
PC - Polycarbonate.
PE - Polyethylene.
PET - Polyester & Co-Polyester.
PETG - Polyethylene Terephthalate Glycol.
PMMA - Polymethyl Methacrylate.
PP - Polypropylene.
PS - Polystyrene.
PU - Polyurethane.
PVC - Polyvinylchloride.
SAN - Styrene Acrilonitrile.