Innovation Chem Packaging Series
1. Why Resin Choice Matters
Selecting the wrong plastic can shorten shelf life, fade colours or—even worse—leak corrosive liquids in transit. Two resins dominate industrial and household chemical packaging:
| Resin | Best for | Why it Works |
|---|---|---|
| PET / rPET | High-alkaline, water-based cleaners (pH 9 – 12) | Ester backbone resists mild alkali and offers glass-clear transparency for vibrant dyes. |
| HDPE | Acidic descalers, rust removers, many solvents | Saturated polyethylene chains shrug off strong mineral & organic acids that can stress-crack PET. |
Quick tip: Run a 12-week accelerated compatibility test (40 °C, 75 % RH) before scaling production.
2. Bottle Styles & Sizes (250 ml – 25 L)
| Capacity | Popular Style | Typical Neck | Best Use-Case |
|---|---|---|---|
| 250 – 500 ml | Boston Round (PET or rPET – clear, black, amber) | 24/410 | Premium kitchen & bath sprays, car-care dressings |
| 500 ml – 1 L | Boston or Cylindrical (PET/HDPE) | 28/410 | Household trigger sprays, shampoo refills |
| 5 L | Stackable HDPE Jerry Can | 51 mm TE | B2B cleaning concentrates |
| 10 – 25 L | UN 3H1-rated HDPE Jerry Can | 56 – 61 mm TE | Hazardous goods under ADR/IMDG |
3. Understanding Neck Finishes
A neck finish is expressed as diameter/thread-profile (e.g., 28/410 = 28 mm outer thread, 1 start, 0 thread depth). Matching closures requires absolute precision.
| Finish | Common On | Typical Closures |
|---|---|---|
| 24/410 | 250–500 ml PET & HDPE | Fine-mist sprayers, flip-tops |
| 28/410 | 500 ml–1 L trigger bottles | Trigger sprayers, lotion pumps |
| 31/400 | Wide-mouth HDPE | Child-resistant caps (CRC) for powders & pastes |
4. Trigger Sprayers: More Than a Nozzle
- Head: fan/jet adjuster; outputs 0.9 – 1.6 ml per stroke.
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Gasket / Seal:
- EPDM – best for water-based & alkaline cleaners.
- Viton® (FKM) – premium for oils, solvents & aggressive acids.
- Dip-tube: cut to within 3 mm of the base to reduce “air suck.”
Always specify the seal material when ordering triggers; a Viton upgrade costs pennies compared with a product recall.
5. Caps, Closures & Induction Seals
- Ribbed screw caps – everyday economy; foam or PE liners.
- Disc-tops / flip-tops – controlled dosing of gels.
- Child-Resistant Caps (CRC) – mandatory for corrosive drain openers.
- Heat-Induction Seals (HIS) – foil membranes that create tamper-evident, leak-proof seals after capping & heating.
6. UN-Certified Containers
If you ship hazardous liquids, look for the embossed code 3H1/Y… on the jerry can base. This mark confirms the can passed drop, hydrostatic and stacking tests under UN Recommendations.
7. Quick Selection Matrix
| Product | pH | Bottle | Closure | Neck |
|---|---|---|---|---|
| Kitchen Degreaser | 10 | 500 ml rPET Boston | EPDM trigger | 28/410 |
| Wheel-Acid Cleaner | 2 | 1 L HDPE Cylindrical | Viton trigger | 28/410 |
| Bathroom Descaler Re-fill | 2 | 500 ml Natural HDPE | Flip-top + HIS | 24/410 |
| Industrial Soap | 7 | 5 L HDPE Jerry Can | 51 mm TE cap | 51 mm |
| Snow-Foam Concentrate | 11 | 25 L UN Jerry Can | 61 mm TE cap | 61 mm |
By aligning chemistry, bottle resin, neck finish and closure seal, you’ll cut leakage claims, pass regulatory audits and make your brand stand out—online and on the shelf.
Have a formulation in mind? Contact the Innovation Chem packaging team to prototype the perfect bottle, trigger and cap combo. We can ship samples—from 250 ml PET rounds to 25 L UN jerry cans—so you can start compatibility testing today.