What is the difference between GPPS and HIPS?

GPPS (general purpose polystyrene) is clear, rigid and brittle, used for picture framing, packaging windows and short life vitrines. HIPS (high impact polystyrene) is an opaque, white or coloured sheet with rubber added to improve impact strength, used for thermoformed packaging, refrigerator liners and white goods panels. Same base polymer, very different applications.

Is polystyrene the same as styrofoam?

They are related but distinct products. Styrofoam is the trade name for expanded polystyrene (EPS), the white foam packaging and insulation material. GPPS and HIPS solid sheet are the same base polymer but in a dense rigid form rather than expanded foam. We work with solid GPPS and HIPS sheet, not foam.

Can polystyrene be used outdoors?

Not for long. Standard polystyrene is not UV stable and will yellow, become brittle and crack within months of direct sun exposure. For outdoor signage and display, ACP, acrylic and polycarbonate are much better choices. Polystyrene is best used indoors or for short campaigns where the panel will be replaced anyway.

How do you bond polystyrene?

Polystyrene solvent welds easily with simple solvents like dichloromethane, MEK or limonene based cements. It also bonds reliably with cyanoacrylate (super glue), epoxy and standard PVA wood glue when paired with mechanical clamping. The same solvent sensitivity that makes bonding easy also means polystyrene must be kept away from solvent based cleaning chemicals in service.

Is polystyrene cheaper than acrylic?

Yes, significantly. Clear polystyrene (GPPS) is typically 30 to 50 percent cheaper than acrylic in equivalent thicknesses, which is why it is widely used for budget picture framing and short life clear panels. The trade off is durability. Acrylic will outlast polystyrene by years in any application that sees daily use, sunlight or moisture.

Polystyrene (HIPS / GPPS)

Name: Associated Plastics
Address: 1 Birdwood Ave, Moonah, Tasmania, 7009, AU
Telephone: 1300 198 924
Price range: $$

A rigid, low cost and easy to fabricate plastic available in clear (GPPS) and impact resistant (HIPS) forms for displays, signage and packaging.

Overview

About Polystyrene

Polystyrene sheet is an excellent material for packing, protecting and insulating. It is available in three grades, low, medium and high impact, and in a range of different thicknesses.

High impact polystyrene is the everyday grade. It is one of the most affordable sheet plastics available, thermoforms at low temperatures with excellent detail, and takes printing, painting and adhesive labels well. Food grade polystyrene is widely used for trays and containers. It is not suited to long term outdoor use.

We cut polystyrene to size and CNC route it to shape, and supply full sheets in bulk for thermoformers.

Key Properties

Polymer family: Polystyrene, PS, GPPS (general purpose) or HIPS (high impact)
Density: Around 1.05 g/cm3
Max service temperature: Approximately 70 to 80 C continuous
Light transmission (GPPS): Around 90 percent
Common thicknesses: 0.5, 1, 1.5, 2, 3, 4, 5, 6 mm
Common sheet sizes: 2440 x 1220 mm standard

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Key Features

What makes Polystyrene useful

Clear (GPPS) version with optical clarity close to acrylic at a much lower cost

High impact grade (HIPS) with tough, paintable, white surface for thermoforming

Rigid and dimensionally stable with low moisture absorption

Easy to vacuum form for trays, packaging and signage

Cuts, drills, paints and prints with no special tooling

Available in a wide range of standard colours and finishes

Applications

Common uses for Polystyrene

Picture frame glazing (clear GPPS)

POS display covers and short life vitrines

Vacuum formed packaging trays

Yoghurt cups, food containers and disposable cutlery

Refrigerator door liners and white goods panels (HIPS)

Sign backing and short term outdoor signs

Modelmaking and architectural mockups

Disposable medical trays

Thermoformed prototypes

Toy components

Foam boards for display (expanded polystyrene)

Decorative wall panels

Pros and Cons

The honest picture

Every material has trade offs. Here is where Polystyrene shines and where it falls short.

Pros

Significantly cheaper than acrylic for clear glazing applications
HIPS thermoforms easily and accepts paint, print and adhesive
Lightweight and rigid for its weight
Wide range of colours and finishes available
Vacuum forms at moderate temperatures, making short run production economical

Limitations

Far more brittle than acrylic, ABS or polycarbonate
Not UV stable in standard grades, yellows quickly outdoors
Low chemical resistance, attacked by many solvents and oils
Low maximum service temperature, around 70 to 80 C

Comparisons

Polystyrene versus the alternatives

Acrylic

Clear polystyrene (GPPS) looks similar to acrylic at first glance but is much more brittle, scratches more easily and yellows faster outdoors. It is the budget alternative for picture framing and short life clear panels. Acrylic is the right choice for anything that needs to last.

ABS

HIPS and ABS are often interchangeable for thermoforming, but ABS has much better impact strength and stiffness. HIPS is the cheap option for short life or low stress parts. ABS is the better choice for visible product housings and durable applications.

PETG

PETG is much tougher and clearer than GPPS, with better chemical resistance, but costs more. GPPS is for budget short life clear panels, PETG is the modern replacement where toughness is needed.

Our Services

How we work with Polystyrene

The fabrication methods best suited to Polystyrene, and what we do with them in our Moonah workshop.

CNC Router Cutting

GPPS and HIPS both route cleanly. We cut signage panels, prototype components and packaging blanks from polystyrene sheet.

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Laser Cutting

Polystyrene can be laser cut, but the edge is typically slightly rough and may need light dressing. For most jobs, CNC routing gives a cleaner finish.

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Custom Fabrication

We solvent weld GPPS and HIPS for short run display and packaging work, and thermoform parts to client moulds.

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Cut To Size

Cut to size GPPS in clear and HIPS in white, black and selected colours, in thicknesses from 0.5 mm to 6 mm.

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FAQ

Polystyrene FAQs

Need Polystyrene for Your Project?

Talk to our team about how we can cut, fabricate or repair Polystyrene for you. Free quotes, expert advice and Australia wide delivery from our Moonah workshop.

Get a Free Quote Call 1300 198 924