Bulk Bag Recycling - Which recycling machine to buy?

2022-03-03 | How to Choose a Machine | By Jack Lin |

Why the Shredder + Extruder + Pelletizer recycling machine is ideal for all kinds of woven bag and raffia production waste?

Recycling gives advantage and competitiveness for woven bag production companies if a higher re-using rate of recycled pellets can be added back to tape extrusion lines.

In most cases, producers can use up to 100% of recycled pellets from production waste such as pp raffia, pp bag, bulk bag, endless tape, while still able to main the strength and quality of the end product (woven bags).

Integrated recycling machine reprocess pp Raffia, FIBC jumbo bag and woven sacks

The following factors may make recycling pp bags, bulk bags, woven sacks, non-woven/woven bags, and FIBC bags become challenging for post-industrial manufacturers:

  1. Difficult to process in one single step

    When recycling has to be done in several processing steps due to the size and strength of the material (ex. FIBC, jumbo bags and bulk bags), it is not cost-effective for the producers in terms of labor, electricity, and occupying too much factory space.

  2. Difficult to retain material property (strength and elasticity)

    After recycling the material degrades excessively and therefore, the reusability of the recycled pellets back into the production lines is relatively low.

  3. Difficult to process heavily printed woven bags

    The degassing and screw design of the recycling machine is not ideal for this type of material with extra amount of ink. (For example, printed pp bags and cement bags.)

Recycled plastic pellets, resin, high quality and reusability
Heavily-printed woven bags recycling in one step

(Comparing to film waste, it is more difficult to cut and feed raffia waste consistently into the recycling machine for its strength and size. Usually, it has to be done in separate steps.)

Simply recycle bulk bags and pp raffia

Repro-One recycling machine provides solutions to the above problems with the following features:

  1. One step process with shredder + extruder + pelletizer all integrated into one simple, easy to operate recycling machine.

    (Instead of having a separate off-line crusher or shredder, POLYSTAR’s Repro-One integrates the shredder with the extruder, allowing a more automated and consistent feeding of the material, which results in stable output and higher quality of recycled pellets.)

    POLYSTAR one step plastic recycling machine process with shredder, extruder, pelletizer

  2. Low processing temperature in the single shaft shredder – higher quality of recycled pellets

    This gentle and short, one-step process ensures minimal material degradation, which allow producers to re-use a higher percentage of the recycled pellets back into the production lines and still meeting the industrial standards (for example, strength and elasticity of jumbo bags and bulk bags for US exports).

  3. Specialized degassing and screw design for processing heavily printed bags

    Special screw design and double degassing system for processing heavily printed materials

    Efficient degassing is another key factor to ensure the pellets are solid (instead of fluffy and hollow in the middle), especially when recycling cement bags or AD*STAR bags that are heavily printed. Recycled pellets from laminated fabric can be used back again in tape line production running at lower line speed.

    The optimal screw design can eliminate the problem of material coming out from the degassing (venting) area almost completely, so the machine can operate at full speed with stable production.

    High efficiency degassing and specialized screw design can process heavily printed woven bags efficiently and obtain good quality pellets.

    Heavily-printed woven bag

    Heavily printed woven bags are usually more difficult to recycle and reuse in post-industrial applications

Raffia producers who recycle in-house have many advantages

In-house plastic recycling solution, recycling process, woven bag recycling

(Plastic recycling in the circular economy – Raffia and woven sector: pp bag recycling, bulk bag recycling, jumbo bag recycling.)

In general, 8% of production waste is generated during the process (from extruder start-up, winding, weaving, bag conversion and printing). The price of raw material is almost doubled comparing to the cost of having it recycled in-house.

Shredder-type machine recycles bags in bulk.

It would make sense for medium and large-sized raffia/woven producers (who generate more than 30~40 tones of scraps per month or more) to recycle the production waste internally to reduce production cost.

The PP production waste are too valuable to be wasted regardless of what the market price is at the moment.

Filler masterbatches, additives and modifiers can also be added during the recycling process to improve the properties even more.

plastic recycling pelletizing machine for PP

The die face cutting design of the Repro-One is designed specifically to work with PP (Polypropylene) material:

  1. Automatic pelletizing speed adjustment

    Prevents pellets sticking due to the higher melting index of PP material. Produces more uniform-sized pellets without labor intervention.

  2. Automatic blade pressure adjustment

    Allows the pressure between the pelletizing blades and the die head to remain constant. As a result, there is less machine downtime, easier and faster to change blades.

Water ring pelletizer cut the material into uniform-size

(The pelletizing system of the Repro-One prevents PP pellets from sticking to one another, ensuring stable production and output without having to constantly stop the machine for adjustment.)

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About the Author
Jack Lin

Regional sales manager for Latin America

Jack has visited and spoken to hundreds of POLYSTAR machine users around the world over the last 10 years. Having collected practical information on customer feedback and user experiences, he enjoys sharing the advantages and disadvantages of using different types of machines with others, especially coming from the customers' perspectives.

You can find Jack on LinkedIn.