Resin Data
PPS
Polisulfuro de Fenileno
PPS·High Performance·Semi-crystalline
PPS (Polyphenylene Sulfide) is the "mid-range PEEK": semi-crystalline, resistant to almost any chemical, withstands 200-220°C continuous, inherent V-0, and at the end of the day costs a fraction —$8-20/kg vs $50-100 for PEEK. Its backbone alternates phenyl rings (-C₆H₄-) with sulfur atoms (-S-), a simple structure hiding extreme properties: melting point 285°C, HDT with 40% glass fiber of 270°C+, and chemical resistance surpassed only by PEEK and fluoropolymers.
It's almost never sold pure —it's very brittle with elongation of just 1-2%. Global brands present it always reinforced with 30-40% glass fiber, optionally with added mineral to reduce warpage. The big ones are Toray Torelina (world leader), DIC Corporation, Solvay/Syensqo Ryton (the original brand, 1971), Celanese Fortron, and SK Chemicals/Initz.
Flagship applications: automotive under-hood components (water pumps, thermostats, sensors, fuel system —resists hot gasohol without swelling), robust SMT connectors (competes with LCP but with better weld lines), pumps and valves for aggressive industrial chemicals, and high-frequency 5G components. Processing: mandatory drying 150°C × 4-6h, melt 300-340°C, hot mold 120-150°C for optimal crystallization. Are you running reinforced PPS? Share your experience with warpage and crystallinity in the comments.
The ranges shown in these data tables were compiled by the MVPS team from various parameter sheets and literature, integrating the lower and upper limits for each material type.
This information must be carefully reviewed when developing injection molding processes. Final ranges and processing tolerances are the responsibility of the engineer in charge.
These ranges are not recommended for developing specific process tolerances. MVPS always recommends requesting and consulting the supplier's data sheet.
General Properties
| Chemical Structure | Semi-crystalline |
| Specific Gravity (Density) | 1.35:1 |
| L/D Ratio | 18 – 24 |
| Compression Ratio | 2 – 3 |
| Tonnage Factor | 5.41 – 6.95kN/cm² |
| Thermal Diffusivity | 0.3093mm²/s |
| Max Shear Rate | 50,0001/s |
| Shrinkage | 0.6 – 1.4% |
| Regrind | 25% |
| Heat Deflection (HDT) @ 1.82 MPa | 99°C |
| Glass Transition (Tg) @ 10°C/min | 85°C |
| Vicat Softening @ 50N | 240°C |
Drying
| Drying Temperature | 129 – 149°C |
| Drying Time | 3 – 5h |
| Recommended Moisture | 0.03% |
| Recommended Dryer Type | Desiccant |
| Dew Point | -40°C |
Temperatures
| Melt | 307 – 341°C |
| Nozzle | 310 – 318°C |
| Front | 310 – 318°C |
| Middle | 299 – 310°C |
| Rear | 291 – 302°C |
| Demolding | 118 – 152°C |
| Mold (Cooling) | 102 – 141°C |
| Feed Throat | 35 – 79°C |
Processing
| Back Pressure | 1.7 – 5.2bar |
| Screw Speed | 30 – 60RPM |
| Injection Speed | Medium |
| Barrel Occupancy | 25 – 75% |
| Injection Pressure | 350 – 1,000Pbar |
| Holding Pressure | 88 – 800Pbar |
| Cushion | 6.4 – 12.7mm |
Mold
| Runner Diameter | 3.05 – 6.1mm |
| Gate Diameter | 0.76 – 1.52mm |
| Gate Area | 0.46 – 1.82mm² |
| Wall Thickness | 0.51 – 4.57mm |
Venting
| Depth (Vent Depth) | 0.0203 – 0.0305mm |
| Land (Vent Land) | 0.762 – 1.52mm |
| Width (Vent / Clearance) | 4.06 – 12.7mm |
| Relief (Relief Channel) | 0.2032 – 0.4064mm |
Frequently asked questions
**PPS** (Polyphenylene Sulfide) has very simple chemical structure —phenyl rings (-C₆H₄-) connected by sulfur atoms (-S-). That rigidity gives it exceptional thermal properties (Tm 285°C, Tg ~85°C) but also makes it **inherently brittle** (elongation at break 1-2%, vs 20%+ for ABS). **Industrial solution**: practically all commercial PPS comes **reinforced with 30-40% glass fiber**, optionally with mineral (talc, mica) to reduce warpage. "Pure PPS" or "neat" is offered as a technical reference but rarely injection molded without filler in commercial production.
Five producers dominate ~90% of the world market:
- **Toray Torelina** (Japan) —global leader, high-molecular-weight linear PPS, strong in automotive.
- **DIC Corporation** (Japan) —second largest, DIC.PPS series, strength in SMT connectors.
- **Solvay/Syensqo Ryton** (USA, originally Phillips Chemical 1971) —**the original PPS**, world's first commercial. Leader in industrial/chemical processing.
- **Celanese Fortron** (USA) —Polyplastics/Celanese joint venture, high-MW linear PPS.
- **SK Chemicals / Initz** (Korea) —emerging strong with low-cost automotive grades.
Main differences: **linear PPS** (higher MW, better flow, more impact) vs **cured/branched PPS** (legacy, higher chemical resistance but more brittle).
- **Drying**: **150°C × 4-6 h mandatory**. Final moisture <0.02%. Moisture causes hydrolytic degradation and silver streaks.
- **Melt**: 300-340°C (standard Torelina: 315-345°C). CF grades can go up to 350°C.
- **Mold**: **120-150°C mandatory** for optimal crystallinity (>30%). Cold mold (<100°C) gives amorphous parts with degraded HDT (drops from 270°C to ~110°C, the Tg) —technical disaster for a high-temp application.
- **Residence**: <10 min. PPS is thermally stable but sustained >360°C starts degrading.
- **Injection speed**: medium-fast. Extreme shear thinning —GF grades fill 1 mm walls easily.
Five combined reasons:
- **(1) Hot fuel and biofuel resistance**: doesn't swell or degrade in gasoline, gasohol (E10-E85), diesel, biodiesel, or with modern additives.
- **(2) Continuous hot coolant**: handles hot water-glycol cyclically without issues for years (water pumps, thermostats, sensors).
- **(3) Lubricating and transmission oil resistance**: doesn't soften with ATF, motor oil, or brake fluid.
- **(4) Dimensional stability**: under-hood thermal cycle (-40°C to +150°C) doesn't cause creep or significant dimensional changes.
- **(5) Inherent V-0 without halogens**: compliance with EU automotive regulations (REACH) and California (Prop 65).
Standard OEM applications: PPS in water pump impellers (Toyota, VW), oil pumps, temperature sensors, exhaust gas recirculation (EGR), fuel injection components.
Both are lead-free reflow compatible (260°C+), but different:
- **PPS wins on**: **weld line strength** (PPS 60-80% of base material vs LCP 20-40%), **less anisotropy**, **lower cost** ($10-20/kg vs $15-30/kg), geometric versatility.
- **LCP** ([Liquid Crystal Polymer](/en/desktop/datos-de-resina/lcp)) **wins on**: **ultra-thin walls** (0.15 mm is trivial vs 0.3 mm for PPS), **extreme MD dimensional stability** (nearly metallic CTE), better for high-frequency connectors.
**2026 rule**: for SMT connectors with weld lines and complex geometry → **PPS**. For fine-pitch (0.3 mm or less) and high-frequency board-to-board → **LCP**.
**Anisotropic and very low** with glass fiber:
- **40% GF (most common)**: **0.2-0.5%** in flow direction, **0.5-1.0%** transverse.
- **30% GF**: 0.3-0.6% MD, 0.7-1.2% TD.
- **Pure PPS (rare)**: 1.0-2.0% (high due to crystallization).
- **Mineral+GF (low-warp) grades**: 0.2-0.4% MD, 0.4-0.7% TD —most balanced.
The **low shrinkage** is what allows PPS to replace metals (zamak, aluminum) in pumps, thermostats, and connectors with strict tolerances. Keeping **constant hot mold** is key for reproducibility —10°C differences between cavities generate dimensionally different parts.
**Excellent, second only to PEEK and fluoropolymers among standard thermoplastics**:
- **Not attacked** by: mineral acids up to 200°C (HCl, H₂SO₄ <60%), strong bases (NaOH 50%), all common organic solvents (acetone, MEK, toluene), aromatic hydrocarbons, fuels, oils.
- **UNIQUE resistance in plastics**: **no known solvent** dissolves PPS below 200°C.
- **Limits**: concentrated oxidizing acids (fuming nitric acid, oleum) attack it; **elemental chlorine and bromine** degrade it slowly. **Doesn't resist sustained steam** >200°C (slow hydrolysis).
That's why it's standard in **industrial chemistry pumps** (acid handling), **paper pulping components**, **hospital cleaners**.
**Linear PPS** dominates ~85% of the modern market. Differences:
- **Linear PPS**: high molecular weight (10-50k), better processability, better impact, better flow. Standard Toray Torelina, Fortron.
- **Cured PPS (crosslinked)**: produced by heating branched PPS in oxidizing atmosphere to crosslink. More limit chemical resistance, but **more brittle and harder to injection mold**. Original Ryton was cured.
**2026 trend**: cured remains in specific maximum-chemical-resistance applications (industrial chemical equipment). For everything else (automotive, SMT, electrical), high-MW linear PPS.
**Mechanically yes**, up to 25-30% regrind in industrial without significant loss. **Thermally stable**, withstands multiple extruder passes —but **each pass slightly degrades glass fibers**, reducing mechanical properties. For SMT connectors and critical automotive parts: max 15-20% regrind. For less critical applications, up to 30%. **Post-consumer recycling** is very limited —reinforced PPS is hard to separate from other plastics in municipal streams and usually ends up in mixed metals+plastics from automotive shredders.
**Warpage from unbalanced crystallinity**. PPS with GF crystallizes more in zones seeing hot mold than in those seeing gate or fast flow —if cavities aren't thermally balanced or cycle time is short, the part comes out **warped** with internal stress. **Cure**:
- Uniform hot mold **130-150°C** on both halves.
- Sufficient cycle time for crystallinity (~30 s for medium parts).
- **Balanced cooling channels very close to cavity**.
- Optional **post-mold annealing** 2-4 h at 200°C for dimensionally critical parts (relieves stress and completes crystallization).
Second issue: **insufficient drying** → silver streaks and bubbles (same as all high-temp aromatics).