The pet bottle flakes are pure materials processed through sorting, crushing, washing, decontamination, and other recycling processes.
At present, the primary use of PET bottle flakes after washing and drying is to manufacture polyester staple fibre, and medium and high-end bottle flakes can be applied to filament products, of which the most special is food-grade pet flakes, which need to be combined with a pelletising system with viscosity-increasing function to be processed into raw materials for recycled bottles.
Application of different grades of pet bottle flakes：
1.Short fiber:
Filling: quilt, pillow, mattress, sofa cushion, plush toys, etc.
Spinning:Clothing material, garment interlining, socks, shoe material
Nonwoven:Filter material, car decoration material, audio cloth, yarn, tennis ball, sound-absorbing material
2.Filament:
Clothing materials, blankets, bed sheets, towels
3.Food grade:
Injection moulded parts, lunch boxes, recycled bottles
Post-consumer PET bottles are unpacked, metal separated, labels removed, whole bottle washed, automatically picked, manually re-selected, shredded, hot/cold washed, dewatered and dried, dust separated, metal separated, flake material sorted, flake colour sorted, aged flakes removed and then sold directly to manufacturing companies.
Boxin ensures that the equipment produces a qualified PET flake product that meets the needs of downstream products and market demands. Our final flake quality is for reference.
Item | Parameter |
Viscosity | 0.71~ 0.78 dl/g, this system will not change the viscosity of the raw material itself. |
Packing density | 200~300 Kg/m3 |
Size | ≤12 mm (customised screen size for pulveriser) |
Moisture content | <3% |
PP / PE | <100 ppm |
Paper | <100 ppm |
Adhesive, hot melt | <100 ppm |
Metal | <100 ppm |
PVC | <100 ppm |
Total impurity content | <200 ppm |
Item | Parameter |
Viscosity | 0.71~ 0.78 dl/g, this system will not change the viscosity of the raw material itself. |
Packing density | 200~300 Kg/m3 |
Size | ≤12 mm (customised screen size for pulveriser) |
Moisture content | <2% |
PP / PE | <70 ppm |
Paper | <70 ppm |
Adhesive, hot melt | <70 ppm |
Metal | <70 ppm |
PVC | ≤30 ppm |
Total impurity content | <100 ppm |
Item | Parameter |
Viscosity | 0.71~ 0.78 dl/g, this system will not change the viscosity of the raw material itself. |
Packing density | 200~300 Kg/m3 |
Size | ≤12 mm (customised screen size for pulveriser) |
Moisture content | <1% |
Tab | <15 ppm |
PP / PE | <15 ppm |
Inorganic Compound | <10 ppm |
Paper | <10 ppm |
Adhesive, hot melt | <10 ppm |
Metal | <10ppm |
PVC | <10ppm |
Total impurity content | <100 ppm |
The output of high-quality flakes is not only very demanding in terms of raw material inputs, but also in terms of the recycling process used in the supplier’s pet bottle washing line.
Quality bundles of PET bottles are the key to recycling. Help you start the first step of your recycling programme by understanding the composition of bottle bundle recommended by Boxin Machinery.
Description | property |
PET containers | Single opening bottle |
Average container weight | 25~ 40 gm |
Heterochromatic rate (heterochromatic and opaque bottles) | Excessive coloured bottles will increase the number of labourers for manual selection, the PET bottle brick raw material should be pre-screened for colour, if the rate of mixed colours and non-PET is more than 20%, we suggest the customer to set up a pre-screening system for the whole bottles. The content of bottle source data provided by the demand side is as follows: 1. 1, compressed bottle bricks within the territory 2、Non transparent PET content |
Bottle base | There is no restriction on whether there is or not, but the material is PP or PE. |
Label (heat shrink or adhesive) | Label peeling on the production line is done mechanically in two steps. Label materials that can be processed include paper, BOPP, PET and PVC. The bottle content of heat-shrinkable labels (PVC, etc.) should not be more than 50% of the input material. If it is more than 50%, it is recommended to set up two stripping units or to add a stripping reflux system after automated/manual sorting in order to avoid the burden of reprocessing. The label content data provided by the demand side are as follows. BOPP% PET Label % PVC Label % |
Bottle Cap | (Suspension material) PP, HDPE, EVA, PP (suspension material). |
Bottle cap gaskets | EVA, PP (suspension material) If the gasket is made of PVC or rubber, it can be automatically screened out by an additional bottle screening machine. |
Adhesive | Hot melt, insoluble in water |
Rubbish | Any impurities that may have been mixed in at the recycling site. These include sand, dirt, glass, inorganic materials, organic materials, ceramics, paper, residual liquids, etc. The total waste content should not exceed 20 per cent. The total waste content should not exceed 1 per cent. |
Total content of non-PET packagings (excluding PVC/PP/PE packagings) | Non-PET packagings (excluding PVC/PP/PE packagings) shall not exceed 0.1% of the gross mass. |
PVC containers | Maximum 0.1 per cent |
PE, PP containers | Up to 1 per cent. This type of packaging will only cause a change in the output rate and will not have an impact on the quality. |
Magnetic metals | Size > 5.5 mm, max. 0.5-1% |
Aluminium and non-magnetic metals | Size > 5.5 mm, max. 0.5-1 per cent |
PVC labels on heat-shrinkable bottles have always been a major problem for PET recycling, and if the PVC content in the finished flakes is too high, it will directly affect recycling!
Boxin’s patented new wet label stripping blade solves this problem by firstly using the stripper blade with water to tear the label from the surface of the bottle, and then with the label blowing device, using the difference in specific gravity and area to completely separate the bottle from the label under the action of the adjustable wind force.
We suggest to add the whole bottle cleaning equipment after the de-labelling machine. This equipment can not only carry out pre-cleaning but also secondary de-labelling.
The optimum residence time for bottle flakes in a hot wash system is 10 to 15 minutes, while common hot washers use a row in-line distribution, often with insufficient residence time. High quality flakes must have a 1+2 or 2+1 hot wash layout. The use of a distributed structure allows for the setting of flake dwell times.
In contrast to fibre grade flakes, the detergents added to the hot wash system must be neutral to ensure that the optimum pH value of the finished product is maintained at 7.5 ± 0.5.
Dehydrated and dried flakes usually contain a variety of fine debris and dust, which can be effectively removed using a z-scaler.
The core of high quality flakes lies in the removal rate of non-PET materials, Boxin suggests that the food grade flakes production line adopts 2 times automatic selection + 1 manual re-selection.
1. Optical sorting of the material and colour of the whole bottle before the PET bottle enters the crushing process.
2. After the automatic selection, manually carry out the second re-selection before crushing.
3. After dehydration and drying of flakes, material, colour, violet light sorting of aged flakes and eddy current sorting (the bottle package contains aluminium and non-magnetic metal).
A variety of factors go into setting up a PET bottle washing line, including the impurity rate of the raw material, the size and capacity of the line, the type of equipment used, the grade of the finished product to be processed, and the location of the line, among others.
Usually the production capacity of the line is 500KG/H ~ 6000KG/H (discharge volume), of which 2 tonnes ~ 3 tonnes/H is the most popular.
Let’s take 2000kg/h fibre grade pet bottle cleaning as an example, its price is usually between 15w ~ 20w USD.
Before making a decision, it is important to carefully research and compare different plastic washing lines to make sure the one you choose fits your needs and budget.
You can check out our: how to pick the right plastic recycling machine manufacturer
Conveying unit: metal chain plate conveying, single/double screw conveying, belt conveying
Used for the transmission of each unit in the process of pet bottle recycling.
Selection unit: automatic selection of whole bottles, manual selection, automatic selection of flakes.
Used to remove non-PET materials contained in the pet bottle packages to improve the quality of the final product.
Separation units: tumbler sieves, de-labelling machines, metal removers, eddy currents, z-type suction labellers.
Washing unit: hot washing, rinsing, friction washing
Drying unit: dewatering machine, tube drying
View our plastics recycling support equipment
I'm the subject editor for Boxin Machinery and I've been working in the plastics recycling field for 15+ years .