Choosing the right material keeps your product safe, protects its shelf life and makes sure it looks right on the shelf. This guide covers the materials we carry, what each one does well and what to watch out for. Plastics are identified by a resin code from 1 to 7, usually molded into the bottom of the container.
PET (#1) · Polyethylene terephthalate
PET is the clear, lightweight plastic used for most water and soda bottles. It is shatter-resistant and holds its shape well, and it is a good barrier against moisture and gases such as oxygen and carbon dioxide.
Properties
- Clear, glass-like appearance at a fraction of the weight
- Shatter-resistant
- Good barrier against moisture, oxygen and carbon dioxide
- Works well with water, juices, oils and many personal care products
- Maximum temperature of about 140–160°F, so it is not suited to hot filling
Watch out for
- Heat above 140–160°F, which can warp or soften the container
- Strong solvents such as acetone, and strong alkaline products
Common uses: beverages, food jars, salad dressings, mouthwash, shampoos and clear retail packaging. PET is one of the most widely recycled plastics.
HDPE (#2) · High-density polyethylene
HDPE is a tough, durable plastic with excellent chemical resistance, which is why it is the go-to choice for household and industrial chemicals. It is naturally translucent and is often colored or made opaque white.
Properties
- Strong and impact-resistant; semi-rigid to rigid depending on wall thickness
- Excellent resistance to acids, bases, bleach, alcohols and detergents
- Good moisture barrier
- Maximum temperature of about 248°F
Watch out for
- Products that need an oxygen barrier, since oxygen passes through HDPE more easily than PET or glass
- Fuels, solvents, and some essential oils and fragrances, which can soften the container or pass through the walls
Common uses: cleaning products, bleach, chemicals, detergents, supplements, milk jugs and personal care. HDPE is one of the most widely recycled plastics.
PVC (#3) · Polyvinyl chloride
PVC is a rigid, clear plastic. In packaging it is mostly used for blister packs and clamshells, and it is much less common for bottles and jars than it once was.
Properties
- Rigid and clear
- Good resistance to many oils and chemicals
- Maximum temperature of about 140°F
Watch out for
- Long sunlight (UV) exposure, which breaks it down over time
- Heat above about 140°F
LDPE (#4) · Low-density polyethylene
LDPE is soft and flexible, so it is easy to squeeze. That makes it the natural choice for squeeze and dispensing bottles. Like HDPE, it holds up well to most chemicals.
Properties
- Very flexible and squeezable
- Good resistance to acids, bases and alcohols
- Translucent, or opaque when colored
- Maximum temperature of about 176°F
Watch out for
- Products that need a strong oxygen or moisture barrier
- Heat above about 176°F
Common uses: squeeze bottles, dropper and dispensing bottles, condiments, lab wash bottles, film and bags.
MDPE · Medium-density polyethylene
MDPE sits between LDPE and HDPE: stiffer than LDPE and more flexible than HDPE. It has the same good chemical resistance as the other polyethylenes and is often used for squeezable bottles and tubes that need to hold their shape.
PP (#5) · Polypropylene
PP is strong, durable and the most heat-resistant of the common packaging plastics. It is used for most caps and closures, and it bends without breaking, so it works for the flip-top hinges on dispensing caps.
Properties
- High heat resistance, up to about 275°F, so it handles hot filling and dishwashers
- Strong and fatigue-resistant; makes durable living hinges on flip-top caps
- Good resistance to acids, bases and alcohols
- Good moisture barrier
- Translucent, opaque or any color
Watch out for
- Freezing temperatures, which can make PP brittle
- Products that need a strong oxygen barrier
Common uses: caps and closures, jars, food containers, supplements, and anything hot-filled or washed in a dishwasher.
PS (#6) · Polystyrene
PS is a rigid plastic with excellent, glass-like clarity, which makes it popular for cosmetic jars and display packaging. In its rigid form it is brittle and has little flexibility.
Properties
- Excellent clarity and a high-gloss finish
- Rigid and holds its shape
- Low cost
Watch out for
- Drops and impacts, since rigid PS can crack
- Solvents, citrus oils and many essential oils, which can craze or crack it
- Products that need a moisture or oxygen barrier, since PS is a poor barrier
- Heat; PS is not suited to hot filling
Common uses: cosmetic jars, balms, dry goods and clear display packaging.
Other (#7)
Resin code 7 covers every plastic outside codes 1–6, such as polycarbonate (PC), acrylic and plant-based PLA, as well as multi-layer blends. Properties vary widely, so check the product details or ask us.
Glass
Glass is chemically inert, so it won’t react with your product, absorb its scent or flavor, or let moisture and gases through. Amber glass also blocks most UV light, which protects light-sensitive products.
Properties
- Inert, with excellent chemical resistance
- Impermeable to moisture and gases
- Clear, or tinted (such as amber) for light protection
- Premium look and feel
Watch out for
- Breakage from drops or impacts, and added weight for shipping
- Sudden temperature changes, which can crack it
Common uses: essential oils, tinctures, serums, food, sauces and premium packaging.
Metal
Metal containers such as tins and aluminum bottles are durable and fully opaque, so they block light, moisture and oxygen.
Properties
- Complete barrier against light, moisture and oxygen
- Durable and fully rigid
Watch out for
- Dents from heavy impacts
- Acidic or salty products, which can corrode unlined metal; use a lined container or test first
Common uses: balms, salves, candles, tea, dry goods and light-sensitive products.
Phenolic (closures)
Phenolic is a hard thermoset plastic used for caps. It is known for its heat resistance and its resistance to many solvents and oils, which makes it a common choice for closures on essential oils, solvents and lab chemicals.
Watch out for
- Overtightening; phenolic is hard but brittle, so a cap can crack under too much torque
Choosing the right material
- Clear bottle for beverages or personal care: PET
- Cleaning products, bleach and chemicals: HDPE
- Squeeze and dispensing bottles: LDPE
- Hot filling or dishwasher use: PP
- Clear cosmetic jars for creams and balms: PS (avoid for essential oils)
- Essential oils, tinctures and light-sensitive products: amber glass with a phenolic or PP cap
Disclaimer: Temperatures are typical maximums and vary with the grade, wall thickness and how long the container is exposed. This information is based on general industry recommendations and is not a guarantee. It is the customer’s responsibility to test for product compatibility; we’re happy to send free samples so you can test before you buy.
