HIPS HI
Grade
ASTM D4549 · ISO 1043-1 PS-HI, 2897 · also Styron HIPS
HI = high / super-high impact HIPS
Pick when drop-impact or low-temperature toughness dominates and stiffness can be traded away.
Values for the HI condition
Other HIPS grades and fills
HIPS is listed in 6 conditions; see the grade overview at HIPS.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
HIThis page High / super-high impact HIPS | Pick when drop-impact or low-temperature toughness dominates and stiffness can be traded away. | 20 | 21 | 55 | 88 HRR |
Recycled / regrind-containing HIPS | Cheapest option for non-critical hidden parts and sheet cores; properties vary lot to lot. | 21 | 22 | 20 | 76 Shore D |
Antistatic / static-dissipative HIPS | For electronics trays, packaging and covers where charge build-up must be bled off. | 22 | 24 | 25 | 76 Shore D |
flame-retardant HIPS (UL 94 V-0) | Required for TV/monitor back covers, power-tool and appliance housings needing V-0 or V-2 listing. | 23 | 24 | 20 | 76 Shore D |
Mineral / talc-filled HIPS | Cost-down / stiffness-up option for large flat panels where impact can be sacrificed. | 24 | 24 | 8 | 80 Shore D |
High-heat HIPS | For parts near warm electronics or hot-fill/steam-clean exposure where standard HIPS softens. | 26 | 28 | 30 | 79 Shore D |
What is HIPS HI?
HIPS HI is HIPS in the HI grade — pick when drop-impact or low-temperature toughness dominates and stiffness can be traded away. HIPS HI has a yield strength of 20 MPa (2.9 ksi) and a tensile strength of 21 MPa (3.05 ksi) — weaker than 80% of polymer grades. Elongation at break is 55% and the elastic modulus is 1.6 GPa (0.232 Msi). HIPS HI has a density of 1.04 g/cm³ (0.0376 lb/in³), lighter than 71% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Advantages
- Readily welded — 80/100, better than 86% of polymer grades
- Forms and bends easily — 88/100, better than 85% of polymer grades
- Low moisture uptake — 0.07%, better than 81% of polymer grades
Limitations
- Degrades in UV without stabilisers — 18/100, worse than 93% of polymer grades
- Limited service temperature — 65°C (149 °F), worse than 83% of polymer grades
- Low strength — 20 MPa (2.9 ksi), worse than 80% of polymer grades
- Poor heat conductor — 0.16 W/m·K (0.0924 BTU/hr·ft·°F), worse than 78% of polymer grades
HIPS HI properties
Typical room-temperature values for HIPS HI; 11 are specific to this condition. Other listed values are HIPS reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
HIPS HI has a density of 1.04 g/cm³ (0.0376 lb/in³), lighter than 71% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical14
HIPS HI has a yield strength of 20 MPa (2.9 ksi) and a tensile strength of 21 MPa (3.05 ksi) — weaker than 80% of polymer grades. Elongation at break is 55% and the elastic modulus is 1.6 GPa (0.232 Msi).
Thermal11
HIPS HI is rated for continuous service to 65°C (149 °F). It conducts heat at 0.16 W/m·K (0.0924 BTU/hr·ft·°F), worse than 78% of polymer grades. Thermal expansion is 80 µm/m·K (44.4 µin/in·°F).
Electrical7
HIPS HI is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (72/100), worse than 70% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of HIPS HI takes about 92 MJ of energy and emits 3.5 kg of CO₂ — less than 74% of polymer grades. Typical recycled content is 10%.
Manufacturability8
HIPS HI's machinability is good (65/100, better than 66% of polymer grades); weldability very good (80/100); formability excellent (88/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with HIPS HI
Is HIPS easy to machine?
Machines and dies easily with sharp, positive-rake tools and high speed/low feed; avoid heat build-up (smearing) and avoid cutting fluids containing solvents that stress-crack it.
Can HIPS be welded?
Excellent ultrasonic, hot-plate, spin and solvent (MEK/toluene-based) welding; also readily bonded with cyanoacrylate and styrene cements.
Can HIPS be formed, bent or molded?
Very easy injection molding at 190–250 °C melt with 20–60 °C molds; predrying 2–3 h at 70–80 °C recommended; sheet thermoforms cleanly at 140–180 °C with low forces.
What surface finishes work on HIPS?
Takes hot stamping, pad/screen printing, vacuum metallizing and paint well (use styrene-compatible primers); poor UV durability means outdoor parts must be painted or capped.
HIPS chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| polybutadiene rubbergrafted/occluded salami-type rubber particles 0.5–5 µm | 4 – 12 | 7 |
| mineral oil (internal lubricant/plastici | 0.5 – 3.5 | 2 |
| antioxidant / stabilizer package | 0.05 – 0.5 | 0.2 |
| residual styrene monomerfood-grade limits lower | 0 – 0.1 | 0.03 |
| polystyrene (styrene monomer units)continuous glassy matrix | ≥ 88 (balance) | — |
HIPS HI — frequently asked
What is HIPS HI used for?
HIPS HI is typically used for refrigerator liners, TV/appliance housings, toys, signage and displays and thermoformed packaging trays. In short: impact-toughened polystyrene; easiest thermoforming styrenic; low-cost opaque housings.
What is the yield strength of HIPS HI?
HIPS HI has a typical yield strength of 20 MPa (2.9 ksi) and a tensile strength of 21 MPa (3.05 ksi) — weaker than 80% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is HIPS HI easy to machine?
Reasonably — machinability is rated good (65/100, better than 66% of polymer grades). Machines and dies easily with sharp, positive-rake tools and high speed/low feed; avoid heat build-up (smearing) and avoid cutting fluids containing solvents that stress-crack it.
Can HIPS HI be welded?
Yes — weldability is rated very good (80/100). Excellent ultrasonic, hot-plate, spin and solvent (MEK/toluene-based) welding; also readily bonded with cyanoacrylate and styrene cements.
What surface finishes work on HIPS HI?
Takes hot stamping, pad/screen printing, vacuum metallizing and paint well (use styrene-compatible primers); poor UV durability means outdoor parts must be painted or capped.
Can HIPS HI be formed, bent or molded?
Very easy injection molding at 190–250 °C melt with 20–60 °C molds; predrying 2–3 h at 70–80 °C recommended; sheet thermoforms cleanly at 140–180 °C with low forces.
What is the maximum service temperature of HIPS HI?
HIPS HI is rated for continuous use to about 65°C (149 °F), and briefly to 85°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D4549 — Standard Classification System for Polystyrene and Rubber-Modified Polystyrene Molding and Extrusion Materials — ASTM International (2020)
- ISO 2897-1/2 — Plastics — Impact-resistant polystyrene (PS-I) moulding and extrusion materials — ISO (2021)
- GB/T 4454 — HIPS — SAC (2018)
- Engineered Materials Handbook Vol. 2: Engineering Plastics — ASM International (1988)
- HIPS resin datasheets (Styron/Trinseo, Chi Mei PH series, INEOS Styrolution Styrolux/PS-I) — various producers (2023)
- CAMPUS plastics database — PS-I entries (ISO 527 / ISO 75 / ISO 306 data) — CWFG (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.