Author: Ahmed Javed Jamal, Country Manager, Silkflex Bangladesh LimitedΒ
How a screen-printing unit uses energy, how low-cure chemicals help, which savings are evidence-backed, and what to do first.
Bangladesh has 883 textile printing units, and in most of them the largest energy user is the conveyor dryer or tunnel oven at the end of the line. Many of those units also deal with unreliable power, so every kilowatt-hour and every cubic meter of gas counts.
Published energy data for screen printing alone is thin, because most Bangladeshi studies cover the garment and textile sector as a whole. This article draws on that sector evidence, technical literature, patents and supplier claims. Where a figure comes from a vendor or a patent, it is flagged.
Part 1: The production process, and where the energy goes
Pigment printing is the most common route for screen printing on light fabrics. Discharge printing is used mainly on dark fabrics, and rubber-based pastes are used for raised or flocked effects.
| Stage | What happens | Energy and quality points |
| 1. Pre-treatment | Fabric is scoured, bleached and prepared so it absorbs paste evenly | Pretreatment quality affects hand and wash fastness. |
| 2. Screen making | Mesh is coated, dried, exposed and washed out | Drying cabinets and exposure lamps. LED exposure is claimed to cut energy by 70β90% (patent). |
| 3. Paste preparation | Binder and thickener, pigment and, where needed, a fixer such as Oxal are mixed | One overview lists binder with thickener, pigment, and a fixing agent for prints that are later acid- or enzyme-washed. Low-cure additives are added here. |
| 4. Printing | Paste is forced through the screen onto the fabric on flat or rotary machines | Motors and compressed air. The paste must not coagulate under shear, or it clogs the screen. |
| 5. Flashing and drying | Water is driven off, often at about 110β120Β°C | Gas or electric flash units and dryers. Water must evaporate before cross-linking starts. |
| 6. Curing | Heat cross-links the binder so the pigment is fixed | The largest energy use, typically about 140β160Β°C for 3β5 minutes on cotton. Polyester is cured hotter and shorter (an older overview gives 160β220Β°C for 30β60 seconds). |
| 7. Testing and finishing | Wash, rub and hand checks | A failed batch wastes all the energy already spent on it. |
The key point for energy planning is that stage 6 is set by the chemistry from stage 3. Change the paste, and the oven can change with it.
Part 2: Low-cure chemistry explained
The binder is a polymer emulsion that wraps the pigment and bonds it to the fibre. It forms its tough, water-insoluble film only when the print is heated. Binders are classed as reactive and non-reactive, and non-reactive types need a fixing agent to form a stable film. Standard systems are designed for roughly 225β375Β°F (about 107β190Β°C) according to one patent, so there is a wide range to work in.
Low-cure systems work by making the cross-linking reaction start at a lower temperature. A lower setpoint means less fuel or electricity per hour, often a faster belt, and less dye migration, scorching and shrinkage on polyester blends.
| Chemical type | How it works | What the sources claim |
| Fixer (fixing agent or catalyst) | Cross-links the binder so the print is wash-fast | Controls how much heat the print needs. |
| Oxal fixer | A fixer used in binder-based and rubber-paste printing | Suppliers list Oxal alongside other fixers and auxiliaries, but the sources reviewed give no cure temperature or dosage collected from TDS |
| Water-based low-cure additives | Cross-linking catalyst mixed into the ink | Claimed to cure ink at about 82Β°C (180Β°F) from 150Β°C |
| Cool-cure additives for binders | Catalyst added to binder ranges at 0.5β2% | Some suppliers say ink cures in seven days without full heat curing, though it needs a little heat to start. |
| Low-temperature crosslinkers | Polycarbodiimide and similar agents | In one digital-printing patent, a polycarbodiimide agent at 3.5% cured polyester prints at about 100Β°C for 10β12 minutes without dye migration. |
| Self-crosslinking low-temperature binders | The binder carries its own cross-linking groups | Some suppliers saybinders react below 100Β°C without an external crosslinker, saving energy. |
| Rubber paste (white and clear) | Elastic, ready-to-use paste; white is opaque, clear is a transparent base | Cure temperature is not stated in the sources reviewed in TDS |
Older low-temperature binders used formaldehyde-based resins, and a newer patent points out that its examples release no formaldehyde.
None of the sources quantify the energy saved by low-cure chemistry, so your own meter readings are the real evidence. Rubber and binder products are sold in Bangladesh by local chemical suppliers, so trials need not depend on imports.
Part 3: Other ways to cut the bill
- Recover heat. A Bangladesh case study reported paybacks of 6 months to 3 years for heat recovery. An experiment found about 13.6% fuel saved in a gas-fired stenter, and a stenter supplier claims up to 25β35% (an upper bound). A small dryer can duct its exhaust heat to preheat incoming air.
- Insulate and seal. A trade supplier estimates better dryer insulation cuts radiation losses by 5β10%. Fixing leaks and switching off idle equipment cost little.
- Dewater first. Removing water mechanically costs far less energy than evaporating it.
- Upgrade the small loads. LED lighting, efficient fans and compressed-air leak repair cut electricity cheaply.
- Add solar for electricity. A CPD study of 350 garment factories found that covering 30% of demand with solar could cut average monthly energy costs by 15.7% (sector-wide). Solar provides electricity, not heat, so it does not replace gas- or oil-heated ovens.
- Consider digital printing for short runs. A Bangladeshi trade article says it uses about 90% less water and 30% less electricity, but needs an air-conditioned room around 25Β°C.
The numbers at a glance
| Measure | Headline figure | Source type |
| Low-cure water-based additives | Cure down to about 82Β°C | Chemical Manufacturer |
| Low-temperature crosslinker on polyester | Cure at about 100Β°C | Patent |
| Stenter heat recovery | 13.6% fuel saved | Experiment |
| Integrated heat recovery | Up to 35% | Chemical Manufacturer |
| Dryer insulation | 5β10% of radiation losses | Chemical Manufacturer |
| Machinery optimisation | 10.17% of factory energy | CPD study |
| Rooftop solar at 30% of demand | 15.7% lower energy costs | CPD study |
| LED exposure | 70β90% less energy | Patent |
The small-printer problem
The smallest factories face the biggest gap. CPD reported an efficiency gap of 57.3% for the smallest factories against 8.9% for the largest, linked to older machinery and financing constraints. A roadmap from Stand.earth and Bangladeshi partners calls for grants, pooled funding and financing that does not add debt to suppliers.
Where to begin
- Measure. Sub-meter dryers, compressors and exposure units, and track energy per 1,000 printed pieces.
- Tidy up. Fix leaks and insulation, and stop idle running.
- Change the easy parts. LED lighting, LED exposure and efficient fans.
- Trial the chemistry. Use the six steps above, including your Oxal and other fixers.
- Tune the process. Improve dewatering and right-size oven temperatures and belt speeds.
- Recover heat on dryers and ovens.
- Add solar, sized to electrical loads after demand is reduced.
The bottom line
The biggest opportunity for Bangladeshi screen printers is curing and drying, where the choice of binder, fixer and low-cure additive sets the oven temperature and heat recovery captures what is left. Housekeeping and LED equipment are the cheapest starting points, and solar helps with electricity but not oven heat.
Sources
- Energy Efficiency, Sustainability, and Economic Feasibility in the Textile Industry of Bangladesh. ResearchGate.
- Waste-heat utilization: The sustainable technologies to minimize energy consumption in Bangladesh textile sector. ResearchGate.
- Γinar, C., & Ceylan, Δ°. The effect of the heat recovery on fuel consumption in the stenter machine. ResearchGate.
- An Overview of Digital Textile Printing Technology. RMG Bangladesh.
- Overview on Textile Printing (paste preparation, rubber printing). Textile Society blog.
- Textile Pigment Printing: Chemistry of Binders. Textile Focus.
- Printing Chemical & Pigment for Textile. Dysin, Bangladesh (distributor information).
- Binder for printing; Rubber Clear and Rubber white listings. Echem, Bangladesh.
- Low-cure additive data: Screen Print Direct (Ecotex), Green Galaxy (Warp Drive), Total Ink Solutions (Opti-Drive) (vendor claims).
- How to Cure Water-Based Screen Printing Ink: Complete Guide. Fannon Infrared (under-curing).
