FAQ · short answers with links to the full guides

Frequently asked questions about plastic cores

ROLL Lab · updated 24 October 2026 · sources at the bottom of the page

The questions are collected from the pages of the guide. For each topic you will find the page that covers it in depth.

Guide

• What is a plastic core? It is the rigid PVC, PP, HDPE or ABS tube that a roll of film, paper, fabric or tape is wound on. It is extruded and cut to length. On the shop floor it is also called a tube or, less often, a mandrel. Read more.
• When is a plastic core better than cardboard? When the core comes back and is reused several times, when the area does not allow fibres and dust, or when the roll will see water and high humidity. If none of these applies, cardboard costs less, weighs less and is recycled with paper. Read more.
• How much does a plastic core cost compared with cardboard? At the same size, usually 2 to 5 times a cardboard core. The price depends on polymer, recycled content, wall and quantities. That is why the right comparison is cost per use, not price per piece. Read more.
• Which plastic should I choose: PVC, PP or HDPE? Rigid PVC is the stiffest and the most reused, but it dislikes heat. PP is light and handles higher temperatures. HDPE stays tough in the cold and, with carbon black, resists sunlight. Start from temperature, hygiene, number of reuses and load. Read more.
• Are plastic cores recyclable? Yes, if the polymer is collected separately and clean: European waste code 15 01 02. PVC must be kept apart because it contaminates PP and PE streams. In 2024 the EU recycled 42.4% of plastic packaging (Eurostat, estimate). Read more.
• What does the PPWR change for plastic cores? A core that leaves with the roll is normally packaging. From 2030 it must be recyclable and contain 35% post-consumer recycled plastic (65% from 2040) as an average per plant and year; 10% and 25% if it were contact-sensitive packaging in a plastic other than PET. Reuse remains voluntary. Read more.

How to choose

• What data do I need to request a quote for plastic cores? Wound material, roll diameter and weight, inside diameter with tolerance and shaft type, length with tolerance, process, storage and transit temperatures, environment, hygiene requirements and life cycle (one-way or returnable), plus annual quantities. Read more.
• How do I choose the wall thickness? From the pressure the roll exerts on the core, with two checks: material crushing and wall buckling. Add a margin for creep and temperature, then confirm with a line and storage trial. Read more.
• Can I use the same wall as the cardboard core? Not as a rule. Plastic and cardboard behave differently under load: plastic does not fail suddenly but creeps over time, and it loses stiffness with heat. The wall must be recalculated and tested. Read more.
• Smooth or ribbed bore? Smooth for most air shafts. Ribbed when you need more grip and torque, with slippery materials or friction shafts. Decide with the machine builder. Read more.
• Why does temperature matter so much? Because plastics lose stiffness with heat and creep more under load. According to Fiaptech technical documentation (a company with corporate ties to ROLL), at 50 °C a virgin PVC core loses about 20% of the strength measured at 25 °C. A summer container easily exceeds 50 °C. Read more.

Materials

• Which is the stiffest plastic for cores? Among the common materials, rigid PVC: its modulus is about 2.5–3.5 GPa, roughly twice that of PP and HDPE. PS and ABS are as stiff as PVC or stiffer, but they are used mainly for small cores. Read more.
• What temperature can a plastic core take? It depends on polymer and load. As an order of magnitude, HDT at 1.8 MPa is 54–75 °C for rigid PVC, 50–60 °C for PP and 45–60 °C for HDPE. In continuous service under a roll, stay well below that, with a wall margin. Read more.
• Is recycled PVC as strong as virgin? At the same size it is usually a little weaker: according to Fiaptech technical documentation (a company with corporate ties to ROLL) its 3% strength is about a quarter lower and its loss at 50 °C is larger (about 30% against 20%). With an adequate wall it works well. Read more.
• What is filled PP? It is polypropylene with a mineral filler, usually calcium carbonate. It is stiffer and cheaper than plain PP, but heavier. With about 15% filler it becomes denser than water and ends up with the heavy materials in recycling. Read more.
• When are ABS and polystyrene used? For small, precise cores for tapes, labels and technical films, and for plugs and end walls. ABS stays tough in the cold; polystyrene is stiff and cheap but brittle. Read more.

PVC cores

• Why is PVC so widely used for cores? Because it is the stiffest of the common polymers, creeps little under load at room temperature, resists moisture and chemicals and handles many reuses: more than 35 cycles for virgin PVC according to customer experience reported in Fiaptech technical documentation (a company with corporate ties to ROLL). Read more.
• Do PVC cores suffer in the heat? Yes. The glass transition is around 80 °C, and already at 50 °C strength drops by about 20% (virgin) or 30% (recycled) compared with 25 °C, according to Fiaptech technical documentation (a company with corporate ties to ROLL). A summer container needs a wall margin. Read more.
• Are recycled PVC cores suitable for food contact? Normally not. Recycled plastic in contact with food is allowed only from processes compliant with Regulation (EU) 2022/1616. Food plants use PP, or virgin PVC with a declaration of compliance. Read more.
• How are PVC cores recycled? They are collected separately from PP and PE and sent to rigid PVC recyclers. PVC sinks in water and separates from polyolefins, but if it ends up in their streams it degrades and releases hydrochloric acid, spoiling the batch. Read more.

PP cores

• Are PP cores suitable for food contact? There are virgin PP cores declared compliant with Regulation (EU) 10/2011. Usually, though, the core touches the film and not the food, so compliance is assessed case by case with the supplier’s declaration. Read more.
• Does PP take more heat than PVC? Under light loads, yes: homopolymer PP has an HDT at 0.46 MPa of 100–120 °C. Under high loads the gap narrows: at 1.8 MPa PP sits at 50–60 °C. Under a heavy roll you still need a wall margin. Read more.
• What is the difference between plain and filled PP? Filled PP contains calcium carbonate: it is stiffer and cheaper, but heavier. According to Fiaptech technical documentation (a company with corporate ties to ROLL), the 3% strength rises from 1.15 to 1.51 times cardboard. Read more.
• Do PP cores break in the cold? Homopolymer PP becomes brittle around 0 °C and can split on impact. For outdoor use and winter transport, use copolymer PP or HDPE. Read more.

HDPE cores

• Why are agricultural film cores often black? Because they are made of HDPE with carbon black, which protects against UV during outdoor storage. HDPE also stays tough in the cold and on impact. Read more.
• Is HDPE stiff enough for heavy rolls? It is the least stiff of the three main polymers and creeps most in the heat. Heavy rolls need thicker walls, a pressure check and, where possible, storage out of the sun. Read more.
• How many times can an HDPE core be reused? Fiaptech technical documentation (a company with corporate ties to ROLL) reports, from customer experience, minimum cycles of more than 3 for virgin and more than 5 for recycled. These are indicative minimums: they depend on load, temperature and care on return. Read more.

Plastic or cardboard

• Do plastic cores cost more than cardboard? Yes, 2 to 5 times at the same size. Compare cost per use: if most cores come back and make several trips, plastic can cost less than one-way cardboard. Read more.
• How often must a plastic core come back to pay off? It depends on price and return cost. With a core at 3.5 times cardboard and a return at 20% of the cardboard price, at least 76% of cores must come back, about 4 trips per core on average (ROLL Lab analysis). Read more.
• Is cardboard greener than plastic? For one-way use, usually yes: it is made from recycled fibre and recycled with paper. With many real reuses plastic can have a lower impact per use. You need an LCA comparison with your own data. Read more.
• Is a plastic core stronger than a cardboard one? At maximum load, yes: 2.2 to 3.5 times at the same size according to Fiaptech technical documentation (a company with corporate ties to ROLL). But plastic creeps over time and loses stiffness in the heat: over weeks the comparison must be calculated case by case. Read more.

Reuse

• How many times can a plastic core be reused? It depends on polymer and use. The best-documented published case we found reached 50 reuses in a trial; Fiaptech technical documentation (a company with corporate ties to ROLL) reports minimums from more than 3 (virgin HDPE) to more than 35 (virgin PVC). The decisive figure is the real count in your own loop. Read more.
• How do I organise core returns from customers? With a written agreement on who collects, who pays the freight, who inspects and who absorbs losses; dedicated return packaging; a collection point separate from waste; scrap criteria and a system to count cycles. Read more.
• Will reusable cores need a QR code? If they are declared reusable packaging, from 12 February 2029 (or 30 months after the implementing act) they will need a label and a QR code or other digital carrier for tracking, except in open systems without an operator (PPWR, Art. 12). Read more.
• Is core reuse mandatory under the PPWR? No. The reuse targets of Art. 29 cover pallets, crates, drums and other listed formats; cores are not among them. Reuse is voluntary. Read more.
• Can a certified food company reuse returned cores? Yes, with a risk analysis, validated washing and sanitising, scrap criteria, and a check of the requirements of its certification standard and of customer contracts. Read more.

Hygiene and food

• Are plastic cores suitable for food contact? There are virgin polymer cores declared compliant with Regulation (EU) 10/2011. Usually, though, the core touches the film and not the food: compliance is assessed on the real contact, with the supplier’s declaration. Read more.
• Does the core need a declaration of compliance if the film is for food? It depends on the contact. If the core does not foreseeably touch the food, hygiene requirements are usually enough; if contact is direct or foreseeable, a declaration of compliance with Regulation (EU) 10/2011 is needed. The business placing the food contact material on the market decides. Read more.
• Can recycled plastic cores be used for food film? Only if the recyclate comes from processes compliant with Regulation (EU) 2022/1616, when contact with the food is foreseeable. Post-consumer recycled PVC is normally not suitable. Read more.
• Why is cardboard discouraged in cleanrooms? Because it sheds fibres and particles when it is cut and when it rubs on the shaft. In the cleanest ISO 14644-1 classes, virgin plastic cores are used, deburred, washed and double bagged. Read more.

Moisture and outdoors

• Can plastic cores be stored outdoors? As far as water goes, yes: they absorb no moisture and lose no strength. Sun and heat are the real limits: you need a UV-stabilised polymer, such as black HDPE, and a wall margin for summer temperatures. Read more.
• Which plastic core should I choose for container export? A PP or PVC core with a wall margin, checked at 50–60 °C, because the inside of a container in the sun can exceed those temperatures. Humidity and condensation, which damage cardboard, are not a problem for plastic. Read more.
• Do plastic cores break in the cold? Homopolymer PP becomes brittle around 0 °C and rigid PVC is impact-sensitive below freezing. HDPE and copolymer PP stay tough even at very low temperatures. Read more.
• Why do plastic cores no longer fit the shaft well in winter? Because of thermal expansion: a 3" HDPE core loses about 0.4 mm of bore from 20 to −10 °C, and a 3 m core shortens by about 15 mm. Let cores acclimatise in the department before use. Read more.

Sizes and tolerances

• What are the standard plastic core sizes? The most common are 76 mm (3") and 152 mm (6"). There are also 1", 1.5", 2", 4", 8"–12" and many intermediate metric sizes, such as 70, 100 or 128 mm, tied to specific machines. Read more.
• What tolerance does a core’s inside diameter have? ISO 13542 is used as the reference: plus-only tolerance, +1.2 mm on 76 mm and +1.6 mm on 150 mm. Extruded plastic cores can sit well within these values; for plain shafts buyers ask for a few tenths. Read more.
• What is the TIR of a core? It is the total indicated runout: the swing read on a dial indicator while the core turns on V-blocks. It sums up ovality, wall eccentricity and bow. It is agreed with the customer based on line speed. Read more.
• Is a smooth or a ribbed bore better? Smooth in most cases and in clean areas. Ribbed when more grip is needed, with high torque, slippery films or friction shafts. Read more.
• How is core ovality measured? According to ISO 13542, as the difference between two perpendicular inside diameters: at most 1.5 mm from 70 mm upwards. In practice calipers or three-point bore micrometers are used; write the method into the specification. Read more.

Strength

• How is the strength of a plastic core measured? Usually as the force at 3% deflection between parallel plates, using the ISO 9969 criterion for thermoplastic pipes. Creep tests under constant load are added and, above all, a line and storage trial. Read more.
• Why not use the same test as for cardboard? Because plastic has no failure peak: it goes oval and keeps carrying load. ISO 11093-9 for cardboard measures the peak. The two tests also use different speeds (50–65 against 2–5 mm/min) and do not give comparable numbers. Read more.
• What is creep in a plastic core? It is slow deformation under constant load: the bore closes in the days and weeks after winding. The EN 13476 pipe requirements allow a two-year creep ratio of up to 2.5 for PVC and 4 for PP and PE. Read more.
• What wall does a 6" core need? Much thicker than a 3": for the same wall, doubling the diameter divides the critical buckling pressure by eight. Calculate on the roll pressure, with a margin for creep and temperature, and confirm with a test. Read more.
• How much pressure does a roll put on its core? In the literature, from about 5 to over 100 bar. It depends on material, tension, thickness, number of wraps, lay-on roller and time. Stretch films are the most demanding because they keep shrinking after winding. Read more.

Plugs and end walls

• What are core plugs for? They protect the core bore from crushing and knocks, let you lift the roll with a bar and, in suspension models, keep it raised so that it does not touch the pallet. Read more.
• What is the difference between a core plug and an end wall? The plug goes into the core and is about its diameter. The end wall, or flange, is a disc wider than the roll that protects its edges and keeps it raised. Read more.
• What are roll core plugs made of? Usually polystyrene, polypropylene, polyethylene or ABS; for very high loads also wood or metal. For recycling, the same polymer as the core or an accessory that is easy to separate is best. Read more.
• How do I choose the size of a core plug? On the real inside diameter of the core, with its tolerance, and on the roll weight. A plug that is too loose falls out; one that is too tight can split the core, especially in the cold. Read more.

PPWR

• Is a plastic core packaging under the PPWR? Normally yes: Annex I lists rolls, tubes and cylinders around which flexible material is wound. Only those that are part of production machinery and do not present the product as a sales unit are excluded: both conditions must apply together. Read more.
• How much recycled plastic will cores have to contain? For “other plastic packaging”, 35% from 2030 and 65% from 2040, as an average per plant and year, from post-consumer waste only. If the core were considered contact-sensitive packaging in a plastic other than PET, 10% and 25%. Read more.
• Does recycled industrial scrap count for the PPWR? No. Art. 7 refers to recycled content recovered from post-consumer plastic waste. Reground production scrap does not count. Read more.
• Does the 5% exemption apply to cores? Rarely. It exempts plastic parts weighing less than 5% of the whole packaging unit. In a roll the wound material is the product, so the core is usually the main part of the packaging. Read more.
• Will cores need the harmonised label from 2028? It depends: the obligation in Art. 12(1) does not apply to transport packaging, except for e-commerce. Cores declared reusable, on the other hand, will need a label and QR code from 2029, except in open systems without an operator. Read more.
• Are cores covered by the reuse targets of Art. 29? No. Art. 29 lists pallets, foldable crates, boxes, trays, crates, IBCs, pails, drums, canisters, pallet wrapping and straps. Cores are not included: reusing them is voluntary. Read more.
• Do plastic cores pay the UK Plastic Packaging Tax? Usually yes, if they contain less than 30% recycled plastic and the UK manufacturer or importer is above the 10-tonne threshold. The rate is £228.82 per tonne from 1 April 2026. A core with 30% or more recycled plastic is not taxed but must still be recorded. Read more.

Cutting

• How are PVC cores cut? Normally with a fine-toothed circular saw, which gives the cleanest edge on rigid PVC. A crush knife tends to chip it. Extract the chips and, if needed, deburr the inner edge. Read more.
• How are PP and PE cores cut? The best result comes from a lathe: a clean, square edge and the option to chamfer. With a saw, PP and PE tend to leave strings because of friction heat. Read more.
• Can the same core cutter cut cardboard and plastic? Many machines can, with the same tool or a quick change, but the quality on plastic depends on method and settings. Run a cutting trial on your own tubes before choosing. Read more.
• What length tolerance can be achieved? Automatic machines usually claim ±0.1–0.3 mm. Checking it needs a caliper or a gauge stop: a tape measure, with 1 mm resolution, is not enough. Read more.

Recycling

• What is the waste code for used plastic cores? 15 01 02, plastic packaging, if they are clean. With film still on them they usually become 15 01 06, mixed packaging. The final classification is up to the waste producer. Read more.
• Is PVC from cores recyclable? Yes, in chains dedicated to rigid PVC. It must be collected separately: mixed with PP and PE it degrades at their processing temperatures and releases hydrochloric acid. It separates well from polyolefins by density because it sinks. Read more.
• Can cores with residual film be recycled? As they are, they usually end up as mixed waste. Separating the film from the core gives two streams with value: the core, to reuse or recycle, and clean film. Read more.
• Can a business put used cores in council waste collection? Not as a rule. In the UK, commercial waste must go to a registered carrier with a waste transfer note under the duty of care; in Italy tertiary packaging is excluded from the public service (Legislative Decree 152/2006, Art. 226). Use a licensed contractor, an affiliated platform or the supplier’s take-back scheme. Read more.

Applications

• In which industries are plastic cores used? Mainly in packaging film, agricultural film, geosynthetics and membranes, textiles and nonwovens, and tapes and labels. The dominant reason differs in each: reuse, moisture, hygiene, load or precision. Read more.
• Which material is used for agricultural film cores? Usually black HDPE, because carbon black protects against the sun and polyethylene stays tough in the cold. Alternatively, UV-stabilised PP. Read more.
• Are plastic cores also used for very heavy rolls? Yes, with thick walls and stiff materials such as PVC, but the core must not be treated as a beam: long, heavy rolls are lifted with a steel bar and rested on cradles. Read more.
• When is cardboard still right in these industries? When the roll makes a single trip, the warehouse is dry, the area accepts dust and the roll is used up quickly. In these cases plastic brings no benefit that pays the price difference. Read more.
• Are plastic cores used for aluminium foil and paper? Sometimes: for rolls going to wet areas or internal reuse loops. For high weights and temperatures, as with aluminium foil, metal cores are often used. Read more.

Packaging film

• Which plastic core is used for film rolls? Rigid PVC dominates returnable cores between producer and converter; virgin PP dominates food plants. The most common diameters are 3" and 6". The wall is calculated on the film pressure, with a margin for creep and temperature. Read more.
• Why do stretch film cores fail after a few days? Because the film keeps shrinking after winding and the pressure on the core grows. According to data published by a core manufacturer, failure usually happens within 72 hours with cast film and between 7 and 14 days with blown film. Read more.
• Is a returnable core loop with converters worth it? Yes, if volumes and customers are stable, returns use trips that are already planned and the great majority of cores come back. With a core at 3.5 times cardboard you need a return rate of at least about 76% (ROLL Lab analysis). Read more.
• Which diameters are used for film cores? Mainly 3" (76 mm) for finished rolls and 6" (152 mm) for parent reels. The inside diameter is chosen with the machine shaft, and the tolerance written into the specification. Read more.

Agricultural film

• Why are agricultural film cores made of black HDPE? Because HDPE absorbs no water, stays tough in the cold and, with carbon black, resists UV. It also belongs to the same family as polyethylene film, which makes recycling simpler. Read more.
• Can plastic cores be left in the sun? They can, with care: in the sun the core gets very hot, loses stiffness and can bend. For heavy rolls, store in the shade and use a wall with a margin. Read more.
• How are long agricultural film rolls handled? With a steel bar inside the core and supports on cradles or saddles that carry the roll. A plastic core on its own is not a beam and bends under the weight. Read more.
• Do silage film cores need to be stronger? Yes: silage stretch films squeeze the core even after winding, and rolls spend the summer on the farm. Check the wall in the heat, with a margin for creep. Read more.

Geosynthetics and membranes

• Which core is used for geotextile rolls? Usually a thick-walled plastic core, often rigid PVC, with an inside diameter that suits the lifting bar. For lighter rolls and cold environments, HDPE too. Read more.
• Why do long cores bend? Because under a heavy roll supported at the ends they behave like beams, and plastic has a low modulus and creeps over time. The load must be carried by a steel bar and by cradles or saddles. Read more.
• Can geomembrane rolls be left outdoors on site? The plastic core does not mind rain, but the sun heats it and reduces its stiffness. Rest rolls on cradles and cover them with light-coloured sheets. Read more.
• How is the inside diameter chosen for a geotextile? Starting from the customer’s lifting bar or laying frame: the bar must fit with the right clearance, without making the core work in bending. Read more.

Textiles and nonwovens

• Why are plastic cores used for nonwovens? Because they shed no paper fibres, which are foreign contaminants in hygiene and medical product plants, and because they can be cleaned. Read more.
• Which material for nonwoven cores? Often virgin PP: light, clean and from the same family as polypropylene nonwovens, which simplifies recycling end-of-roll waste. Read more.
• Are cores that stay in the plant packaging? A tube bought empty, used only on your own machines and part of the machinery may not be packaging. If it leaves with the product for others, it normally is. Assess it case by case. Read more.
• Why use coloured cores for nonwovens? Because a fragment of a coloured core is immediately visible on a white product, while a white fragment on white would go unnoticed. It is a simple foreign body control practice. Read more.
• Can the core and nonwoven residue be recycled together? If both are polypropylene and there are no other materials, they can go together into polyolefin recycling. With different polymers they must be separated. Read more.

Tapes and labels

• Which cores are used for tapes and labels? Mainly 1" to 3" cardboard cores. Plastic cores, in PS, ABS or PP, are used when precision, cleanrooms, electronics or reuse are needed. Read more.
• Is an extruded or a moulded core better? Extruded for flexibility on lengths and large volumes; injection moulded for tight tolerances, burr-free ends and integrated details such as notches and flanges, at the cost of one mould per size. Read more.
• Are plastic tape cores recyclable? Yes, if the polymer is identifiable and collected separately. PS and ABS have smaller chains: marking the material on the core helps sorting. Read more.
• Why does core tolerance matter for labels? Because on automatic label applicators a bore that is too large makes the roll slip and shifts the label, and one that is too small stops it being fitted. Read more.
• Is plastic worth it for log roll cores? Often yes: log roll cores stay in-house and come back from slitting, so they lend themselves to reuse. The small cores of finished rolls leave with the product and can stay cardboard. Read more.

Manufacturers

• What should I ask a plastic core manufacturer? Polymer and compound, post-consumer recycled share and how it is documented, strength test method, long-term and hot data, guaranteed tolerances and how they are measured, cutting method, documents for food contact and substances, and willingness to take back used cores. Read more.
• How do I write a specification for plastic cores? With eight measurable items: application, material, dimensions and tolerances, finishes, performance with test method, documents, packing and delivery, acceptance criteria. Read more.
• How do I run a core sample trial? With a few pallets, a trial on the most critical roll in the warm season, bore measurement at 1, 7 and 14 days, a shaft extraction test and, for reuse, an inspection after the first return. Read more.
• Which checks should I make when cores arrive? Inside diameter, outside diameter and roundness, wall, length and appearance on a sample per pallet, with instruments suited to the tolerances, plus a check of the batch documents. Read more.

About

• Who publishes plastic-cores.info? ROLL, an Italian company specialising in packaging and accessories for industrial rolls and reels. The texts are edited by its technical team, the ROLL Lab. Read more.
• Is the guide independent? It is a technical guide with declared sources, published by a company in the industry. That is why we declare our ties: ROLL sells roll accessories and has corporate ties to Fiaptech, a plastic core manufacturer cited among the sources. Read more.
• Do the calculators give guaranteed results? No. They are ROLL Lab estimates based on models and declared assumptions. Every result must be confirmed by a test on the real core and roll. Read more.

Further reading

Sources

1. Sources given on each reference page