The short answer
- Grade: cold water grade if the pouch goes straight into water at room temperature; hot water grade only if it must stay closed until it meets water above 65°C.
- Size: from your fill weight and how bulky your product is. Our standards are 5 × 5, 5 × 7 and 7 × 7 inches.
- Thickness: from 25 micron. 35 micron is our standard for aquaculture sachets.
- Yield: a 5 × 7 inch pouch in 35 micron film uses about 2 g of film, roughly 500 pouches per kg.
A water soluble pouch has one job: hold an exact dose safely until it reaches water, then disappear. Getting it right comes down to four choices. We make these pouches in Coimbatore from our own patented PVA resin, and these are the questions we work through with every new buyer.
Start with what goes inside
Before size or thickness, we always ask what the pouch will hold. Three things about your product decide almost everything else:
- Fill weight per pouch. The dose you want in each one, in grams.
- How bulky it is. 50 g of a light, fluffy powder takes far more room than 50 g of dense granules or pellets. Fill weight alone does not give the size.
- Texture. Fine powder, free-flowing granules, sharp crystals or pellets. Sharp or heavy fills press harder on the film and need it a little thicker.
PVA film dissolves in water, so it suits dry fills: powders, granules and pellets. A wet or water-based fill would start to dissolve the pouch from the inside.
Cold or hot water grade
Choose the grade by when the pouch should open.
| Cold water grade | Hot water grade | |
|---|---|---|
| Dissolves | In water at room temperature | Above 65°C; softens in cold water |
| Choose it when | The pouch goes straight into a pond, spray tank, cistern, mixer or wash water | The pack must stay closed in damp conditions until it meets hot water |
| Typical uses | Aquaculture feed and probiotic sachets, agrochemical and dye packs, cleaning tablets | Hospital laundry bags, garment bags |
Most pouch buyers need the cold water grade. Aquaculture sachets, for example, are dropped into pond water and must release their dose there, so they are always cold water grade.
Choosing the size
Our standard pouch sizes are 5 × 5, 5 × 7 and 7 × 7 inches, and we cut custom sizes to your fill. To find the right one:
- Start from the dose. One pouch, one exact dose: decide the fill weight first.
- Allow for bulk. A bulky powder needs a larger pouch than dense granules of the same weight.
- Leave room to seal. The filled product must not reach the sealing area, or the seal will not close cleanly. A pouch packed to the brim is the most common cause of weak seals.
- Think about the user. A pouch thrown into a pond or a tank is easier to handle when it is not overfilled and floppy.
If you already use a pouch from another supplier, send us its width and height. That is the quickest starting point, and we can suggest changes from there.
Choosing the film thickness
Film thickness is measured in micron: one micron is a thousandth of a millimetre. We make pouch film from 25 micron, to your requirement. Thickness is a balance:
- Thicker film is stronger, better for heavy doses, sharp granules and rough handling in transport. It takes a little longer to dissolve.
- Thinner film dissolves faster and uses less film, so you get more pouches per kg.
35 micron is our standard for aquaculture feed and probiotic sachets. For light powders a thinner film can work; for heavy or sharp fills we usually suggest going up.
From our plant
Strength matters as much as thickness. Our film has a tensile strength of 12 to 18 MPa and stretches 150 to 200% before it breaks (our technical data sheet), so it gives a little under pressure instead of splitting.
How many pouches per kg
Film is priced by weight, so the number of pouches you get from each kg of film matters as much as the price per kg. You can work it out yourself. A flat pouch is two layers of film:
Film per pouch (g) = 2 × width (cm) × height (cm) × micron × 1.25 ÷ 10,000
Here 1.25 is the density of our film in g/cm³, and 1 inch is 2.54 cm. For our standard sizes:
| Pouch size | 25 micron | 35 micron | 40 micron |
|---|---|---|---|
| 5 × 5 in | 1.0 g · about 990 per kg | 1.4 g · about 710 per kg | 1.6 g · about 620 per kg |
| 5 × 7 in | 1.4 g · about 710 per kg | 2.0 g · about 510 per kg | 2.3 g · about 440 per kg |
| 7 × 7 in | 2.0 g · about 510 per kg | 2.8 g · about 360 per kg | 3.2 g · about 320 per kg |
These are film weights before sealing and trimming, so treat them as close estimates. With your quote we confirm the exact weight per piece and pieces per kg for your size and micron.
Ready-made pouches or film rolls
There are two ways to buy, depending on how you pack.
Ready-made pouches
We supply empty pouches cut to your size. Your team fills them and seals them on a heat sealing machine. This suits manual and semi-automatic filling, smaller runs and buyers starting out with water soluble packs.
Film rolls for your FFS machine
For high-speed lines, we supply film on a roll. Your form-fill-seal (FFS) machine forms the pouch, fills it and seals it in one run. Tell us the roll width your machine takes, and whether it needs a single film roll (one flat layer) or a tube roll (a flattened tube closed along both edges).
Storing and handling
The film is made to dissolve in water, so keep water away from it until it is used:
- Store pouches and rolls dry, in their original packing, away from water and damp floors.
- Handle them with dry hands or dry gloves. Wet fingers leave sticky marks on cold water grade film.
- Close opened packs again, especially in humid weather, and use opened stock first.
- Fill with dry product only.
The film is non-toxic and is not hazardous for transport by road, sea or air.
What to send for a quote
With these details we reply within one working day with the weight per piece, pieces per kg, price and lead time:
- What goes inside, and the fill weight per pouch
- Pouch size (width × height in inches), or the pouch you use today
- Micron, if you know it (or we suggest one)
- Cold or hot water grade, or simply how the pouch is used
- Plain or embossed film
- Quantity per order, and how often you reorder
Questions buyers ask
What is the standard size of a water soluble pouch?
Our standard pouch sizes are 5 × 5, 5 × 7 and 7 × 7 inches. We also make custom sizes cut to your fill.
What thickness should a water soluble pouch be?
We make pouch film from 25 micron, to your requirement. Our standard for aquaculture sachets is 35 micron. Heavier or sharper fills need thicker film; thinner film dissolves faster and gives more pouches per kg.
How many water soluble pouches are there in 1 kg?
It depends on size and thickness. A 5 × 7 inch pouch in 35 micron film uses about 2 g of film, so 1 kg of film makes roughly 500 pouches. We confirm the exact weight per piece and pieces per kg in your quote.
Do water soluble pouches dissolve in cold water?
Cold water grade pouches dissolve in water at room temperature. Hot water grade film only softens in cold water and dissolves above 65°C.
What happens to the film after it dissolves?
Our film was tested by CIPET, a Government of India institute, to ISO 17088:2021 and reached 91.04% biodegradation in 165 days. After disposal it breaks down within 1 to 3 months into carbon dioxide, water and biomass.
