This article provides all that you need to know about tape and label cores and how they are used.
You will learn:
A tape and label core is a thick durable tube that forms the center of a label or tape roll with the same shape as that of a toilet paper or paper towel core but is sturdier and more resilient. Although the shape of tape and label cores are somewhat identical, they vary in their strength, size, materials, and thickness with thicker cores used for heavier types of tapes and labels.
A discussion of tape and label cores begins with the core size, which is the diameter of the inner core or inner diameter (ID) while the total diameter across the full length of the tape and core refers to the outer diameter (OD). When purchasing a core, it is necessary to specify the wind direction with eight different directions being available.
The rewind directions are divided by the position of the labels, which can be on the outside or inside of the winding. There are four rewindings for outside positioned labels and four for inside position labels each of which has a different winding direction. Of the eight winding directions, numbers 5 and 8 are seldom used while numbers 3 and 4 are very common and popular.
There are several different forms of tape and label cores that vary in accordance with the types of materials used to manufacture them. The traditional view of a tape and label core is a tightly wound roll of paper that is formed on a mandrel and glued. They are made of various types of paper with Kraft paper being the most common.
Paper tape and label cores are the industry standard and are used for a wide variety of applications. Plastic cores are used when there is a concern for contamination from core dust that is formed by paper cores that flake and produce dust particles. The various types of plastic cores are made of high impact polystyrene (HIPS), high density polyethylene (HDPE), polypropylene, polyvinyl chloride (PVC), and acrylonitrile butadiene styrene (ABS).
The manufacture of tape and label cores follows the same process as that which is used to manufacture any type of core regardless of its use and size. The distinguishing difference between the methods for making tape and label cores is their size. While their strength and resilience can match that of cores used for more rigorous applications, they are measured in inches and millimeters rather than feet and meters.
The type of core is dependent on the application where it will be used, which varies between cores for consumer products and tapes and labels for manufacturing and industrial use. Cores for tape and labels must be sturdy enough to not collapse under the weight of the tape or labels and be able to endure the winding process. This factor is determined by the type of material and the wall thickness of the plastic or paper.
When discussing tape and label cores, it is necessary to understand the difference between tubes and cores. Although the distinction between them may seem to be minor, they are separated by how they are used. Tubes are used for storing and shipping products, such as maps, blue prints, paper work, or long thin products that are placed inside them. Cores have material wrapped around them, such as tape, labels, or fabrics. Tubes are sturdy to protect the items they contain but do not necessarily have the strength of tape and label cores, which are thicker and stronger.
Tape and label cores are made of plastic or paper depending on the type of winding. Plastic is used for sturdy, heavier, and stronger wound materials, while paper cores can be used for the same types of materials if they are wound very thick. In most cases, paper wound cores are used with light to medium tape and labels. There is a great deal of difference between how paper and plastic cores are made due to the radical difference between the materials.
Paper cores are cardboard tubes that are spiral wound in layers of one, two, or more plies. The liner, or inner most layer, and the wrap, the outermost layer, are made of various types of special paper. The types of paper vary and include recycled paper, paper and adhesive composites, cardboard, kraft paper, waterproof cardboard, or fiberboard.
The manufacture of paper cores begins with the forming of strips of paper or cardboard that is trimmed into narrow ribbons. The width of the ribbons or plies can be a few inches (50 mm) up to 10 or 20 inches (254 mm to 508 mm) with thicknesses of 0.008 to 0.050 inch (0.20 mm to 1.3 mm).
The paper strips pass through a pan or container that applies glue to help keep the plies together to form a firm bond. Paper core manufacturers vary in the type of glue used to bond the plies. The types of adhesives fill the gaps between the layers with penetration at less than 20 microns (µ). The tack of the adhesive determines the speed at which the machines can bind the plies. The strength of a core is dependent on the bond strength, the thickness, overlap, and the strength of the adhesive.
The mandrel is a long metal tube upon which the plies are wound. The number of layers of the winding can vary from 1 up to 50 or more with 3 to 30 plies being the most common. Modern mandrels take several forms with ones that can expand and contract to change the inner diameter of a core. The smooth operation of the mandrel is the key to a successful forming of a core. It rotates at an even pace to allow the adhesive to bond the various layers together. A strap or belt provides the power to rotate the mandrel and the angle at which the ribbons feed. Heat from the rotation and movement causes the glue to dry and harden.
The initial winding of the ribbons or plies on the mandrel produces long tubes that have the inner diameter of the cores and their thickness. Once the glue has hardened, the long tube is removed from the mandrel and sent on to be cut to the desired width for the core.
Several methods are used to complete the cutting process with all methods using some form of circular saw. Cutting can be completed manually or be automated. For high volume core manufacturing, an automated process is used that places the long tube on a spinning form of a mandrel as a saw or knife cuts the tube into the desired width of the cores. Since cores come in a wide variety of widths, automated equipment is programmed with the desired width of the core for the completion of precision cuts to meet the programmed dimensions.
The plastic used to manufacture plastic cores include high density polyethylene (HDPE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), and recycled plastics. Each of the various types of plastics have their benefits with strength and durability being their main characteristic.
As with paper cores, plastic cores have different wall thicknesses and come in a variety of sizes from ones with a half inch diameter up to ones with a three inch diameter. Plastic cores are used for a wide variety of applications beyond the manufacture of tape cores. The resilience and strength of the various plastics make them very popular for other uses.
Extrusion is used to produce plastic tape and label cores, which is a process that heats plastic pellets, granules, flakes, or powders and forces the molten plastic through a circular die. The various plastics are made from petroleum that is refined to change their molecular structure to form resin pellets.
The diameter of a plastic core is determined by the inner diameter of the die. The wall thickness is also determined by the shape of the die. The pressure to force the molten plastic through the die is created by a screw that pushes it along the heated barrel of the extruder.
As the tubes exit the die, they are cut at various lengths and allowed to cool before being cut to the widths of the cores. During the cooling process, the lengths of tube set into their final solid shape. The extrusion process is carefully monitored to ensure that the tubing has the proper dimensions for the plastic cores.
Core cutting for plastic cores requires more aggressive cutting equipment due to the strength and density of the plastic materials. As with paper cores, the process is completed using manually operated or automated equipment. The manual method is very similar to that used for paper cores and involves a circular saw. With the automated method, a set of rollers holds the plastic tube and turns it as the circular cutter cuts the core.
The finished cores are sold to tape and label manufacturers to rewind their products. There are several forms of rewinding machines each of which is capable of rewinding using plastic or paper cores. For the process to be successful, the width of the core and the width of the tape or labels have to perfectly match. Rewinding machines guarantee that the tape or labels fit perfectly and are aligned properly.
The wall thickness of a tape and label core determines the strength and durability of the core. The importance of wall thickness varies in accordance with the material attached to the core and the weight of the material. Cores for heavy tape and labels have to be able to maintain their shape under all circumstances. The wall thickness of a core is one of its critical dimensions and determines the ID and OD of a core.
The typical wall thickness for a paper core is 0.125 inch (3.2 mm). For plastic cores, the thickness of the walls of a core are set during the extrusion process with wall thicknesses that can vary from 0.024 in up to 2 or 3 in (0.61 mm up to 50.8 mm or 76.2 mm). The wall thicknesses of paper cores can easily be adjusted by changing the number of ribbons or sheet wrappings.
Paper cores have heavier and more durable walls in order to be able to withstand the stress produced during winding. The thickness of the walls varies depending on the width and diameter of the tape or labels being wound.
Paper tape and label cores are the most used type of cores due to their lower cost and availability. A distinct difference between them is how they are wound with all windings being cylindrical constructs made from layers of tightly wound paper. The two most common types of paper cores are convolute and spiral.
Convolute or parallel cores are manufactured from a single sheet of cardboard where the left hand side of the sheet is rolled over the right hand side of the sheet and glued as it is rolled. Since convolute tubes are wound from a single piece of paper and not ribbons of paper, the edge of the paper is parallel to the axis of the tube.
The structure of convolute cores gives them greater beam strength, which makes them appropriate for more demanding tape and label applications. Since convolute tubes are made from one layer of paper, they have a slightly lower cost than spiral wound cores. Convolute tubes tend to be lightweight and easy to handle but are limited in the number of sizes.
Spiral cores are manufactured by winding ribbons of paper at an angle on a mandrel to form a continuous spiral. The paper for spiral cores is thinner than that used for convolute cores and is made from kraft paper, recycled paper, or certain forms of coated papers. As each layer is applied, it is glued with a high strength industrial adhesive that securely holds the ribbons of paper and provides a smooth even surface.
The process for making spiral cores creates a very smooth surface that is very unlikely to unravel or come apart. The multiple layers of spiral cores make them sturdier, more durable, and crush resistant and capable of withstanding heavy loads. Unlike convolute paper cores, spiral cores come in a wide variety of sizes, such as the ones used for toilet paper rolls and ones that hold duct tape.
Cores for thermal tape can be plastic or paper, which are designed to hold very fine paper that is coated with a chemical that changes color when the tape is exposed to heat. Specially designed cores for thermal tape have a 13 mm and 25 mm (0.5 in and 0.98 in) ID with a wall thickness of 3 mm (0.12 in).
Since plastic cores are extruded, they come in fixed dimensions. They can be solid plastic or honeycombed and come in a variety of colors including white, black, green, and blue.
Kraft paper is used in the manufacture of paper cores due to its exceptional strength, durability, and sturdiness. Unlike other forms of paper, kraft paper is not bleached, which helps it maintain its strength and structure. Additionally, kraft paper is made from wood chips or recycled paper. It comes in large rolls that are cut to the size and shape required to produce tape and label cores.
The word kraft is German for strength, force, resistance, and power. It is used in reference to kraft paper due to the paper’s exceptional properties. The necessary elements for the manufacture of kraft pulp are wood fiber, water, chemicals and heat. The manufacturing process begins with cooking of wood chips.
The process of producing kraft paper begins with steaming, heating, and cooking of wood chips with a solution referred to as white liquor in pressurized containers called digesters. During cooking, the hardened wood chips are transformed into pulp that has been injected with chemicals to increase the pulp’s strength and flexibility. In the presteaming process, the chips are wetted and heated with steam. Cavities are filled with water and air.
In the digester, the wood chips enter at below 100°C (212°F) and are cooked at 170°C up to 176°C (338°F up to 349°F) for several hours. Combined liquids, known as black liquor with lignin fragments, contain carbohydrates from the breakdown of the cellulose and sodium carbonate, sodium sulfate, and inorganic salts.
Wood chips have two structural components, which are lignin and cellulose. In the manufacture of kraft paper, cellulose has to be separated from the lignin since cellulose is the main element in the manufacture of kraft paper. In the digester, the wood chips move from the presteaming stage to the cooking stage along a vertical or horizontal digester.
In the recovery process, the pulp is washed and screened. Weak black liquor, a solution of lignin and other materials, is pushed through evaporators with its final concentration being 65%. The concentrated black liquor has high energy and is burned in a furnace.
The wood chips are blown into a collection tank at atmospheric pressure. This process releases steam and volatiles that are condensed and collected. As the chips are released into the blow tank, their fibers are broken open.
In the washing and cleaning stage, the kraft pulp undergoes various cleaning processes. The black lignin is washed out along with other impurities. Additionally, waste liquids are extracted using high temperature and high concentrate. Pulp washing methods include single stage and multiple stage washing.
Pulp washing is affected by cooking methods, fiber materials, the hardness of the pulp, temperature, pressure, and the degree of vacuum. Washing is completed with various types of equipment including vacuum drum, twin roll press, single screw press, disc filter, and gravity disc thickener.
In screening, large bits of shives, knots, dirt and debris are removed using screens. The screens are set up in stages to form a cascade operation. The brown pulp is separated from the filth to leave clean kraft pulp. The separation process is performed using centrifugal forces that pushes the pulp against the walls of the pressure screener.
The color of kraft pulp is due to residual lignin, which is removed through the bleaching process designed to improve the physical and chemical properties of the pulp. The bleaching process uses a bleaching agent and is completed using reductive bleaching or oxidation bleaching. Bleaching equipment include a screw conveyor, drum washer, roll mixer, pulp chloridizator, and bleaching tower. Kraft paper is not bleached as intensely as other papers since bleaching decreases the strength of the pulp fibers.
The pulp and water are spread across a large mesh screen. Most of the pulp is water, which is removed using gravity, suction, and vibration. In the press section, more water is removed as the mix of pulp and water is squeezed between cloth wrapped cylinders known as wet felts, which is followed by the dryer section where steam dries the pulp reducing the moisture content to 2% to 6%.
During the size press process, the kraft paper has a starch solution applied, which enhances the strength of the paper. In the calendar stack, pressure is applied to the kraft paper to smooth it after which the paper is wound onto a reel by a winder. As the reel of paper is formed, it is cut to a manageable size for shipping.
The cores for the manufacture of tape and labels are sold to tape and label manufacturers. The use of the cores varies depending on the type of tape or type of labels being produced with clear tape, colored tape, heavy tape, and labels using different types of cores. In the case of tape, the process begins with a huge roll of material that passes through a set of stages and the application of glue before being attached to a core.
A further variation in the manufacture of tape is how the cores are used. After cores are wound into tubes, the tubes are cut to the width for the tape for which it is being manufactured. In some tape manufacturing processes, cores are provided to manufacturers in the form of tubes that have not been cut. With this form of manufacturing process, the tape material is applied to the long tube core and cut to the width of the tape.
When individual cores are used, the material for the tape passes through various processes to enhance its strength, make it easier to use, and position it to be placed on a core. At the end of the various steps of the process, slicers divide the tape into the widths for the rolls. The bands of tape are wound around plastic or paper cores. The length of tape that is applied is dependent on the design of the roll and its specifications. Once the rolls are completed, they are ejected, and a new set of cores are positioned.
Tape manufacturing that uses a tube as the core is a process that is similar to a mandrel in that the material is wound around the tube after having passed through the various processes to ensure the quality of the tape. The final step in the process is like the production of individual cores where the long tube is cut to the dimensions and width of the tape.
The manufacture of labels takes much the same form as that used for tape. The biggest difference being the placement, printing, and types of labels. Blank labels are die cut and wound onto a core while printed labels are printed and applied to material before being placed on the core.
When labels are being placed on a core, it is necessary to indicate their wind direction, which can be in eight different rewind positions. The type of rewinding is influenced by how the labels will be removed from the core and includes whether the label is wound out or wound in. The most common form of label rewinding is wound where the label is attached to the exterior of the core and is found in rewinding positions 1 thru 4.
The rewinding position is determined during the manufacturing process where the roll of labels is placed on the core.
Although tape and label cores are referred to as tape and label cores, the cores are used in a wide variety of ways for winding and rewinding various types of materials. How the core is used plays an important part in how a core will be manufactured. This distinction can easily be seen in the difference between cores for paper towels compared to cores for duct tape.
Electrical tape cores are made of plastic to be able to withstand the conditions and environments where the tape is used. Plastic cores have to be able to resist the effects of solvents and chemicals.
Price label cores are loaded into printing machines and designed to rotate and release labels during the printing process. Due to the nature of label printing, price label cores are sturdier and more durable than other forms of cores. They also are capable of enduring the weight of the labels, which are heavier than other types of materials.
Cash register tape takes several different forms with some forms being carbonless two or three ply rolls. The cores of cash register tape are either plastic or paper depending on the type of cash register. Additionally, cash register tape comes in a wide variety of widths, which is also dependent on the type of cash register. The key factor for cores for cash register tape is the ease with which they can be shipped and inserted into the cash register.
Gaffer tape is a highly durable form of tape that can be used for a variety of purposes. It comes with different sizes of cores with ones that are one inch up to ones that are four inches wide. Unlike other forms of tape, and the reason gaffer tape needs a heavy duty core, gaffer tape is made of heavy cotton cloth that is pressure sensitive with an exceptionally strong adhesive. Since gaffer tape is used for heavy duty applications, its core has to be able to withstand the weight and impact the tape experiences during its use.
The majority of tape and label core manufacturing equipment are produced internationally with China being the number one supplier.
The JT-50A is capable of producing cores with 2 to 24 layers with core diameters of 30 mm up to 250 mm. It comes equipped with an Emerson PLC and touch screen with all of the parameters of the core displayed on the monitor. Once the data has been input, the machine starts automatically using a frequency inverter for AC motor control. The unwinding angle is adjustable with a compact spacing structure. The JT-50A has an automatic glue spread with a glue recycle system and glue contained in a stainless steel tank. Single and double side coating is available.
The PTA-4120 has a PLC logic control system with a touch screen interface with an engine using a vector high torque converter speed adjuster. It has a photoelectric length positioning control for automatic changing of cutting speed for greater accuracy. The modular design of the PTA-4120 makes maintenance and repair easier. An important feature of the PTA-4120 is its low level of noise during operation.
The KJT-4D core winding machine is capable of manufacturing cores with 25 mm up to 250 mm diameters and wall thicknesses up to 15 mm. It uses a wax type lubricant to manage the friction between the paper core and the center shaft to provide a more stable and easy control of the spiral gap in the paper core. This particular feature improves the quality of the core and removes the problem of oil stains. The driving mechanism is capable of producing thick walled cores and allows for a choice of winding speeds.
The Crown Spiral Core Machine produces custom cores based on the core design and parameters with varying wall thicknesses, diameters, and lengths. It can produce inside and outside label wrapping using a special unwind reel splicing mechanism for continuous stable production. The glue applicator has a tension adjuster and glue metering to ensure consistent glue flow. The belt reel on the Crown Spiral Core Machine is capable of producing high quality finished cores. It has a servo motor moving cutter system for precision cuts.
The UBR Paper Core Making Machine can manufacture cores with 5 to 30 plies with sliced paper reels located at the top, middle, and bottom transfer rollers. It includes a paper lifting system with a small hoist. Sliced paper reels are individually glued with each gluing unit having a pneumatic tension compressor to ensure the tightness of the unwinding. The main drive of the unit is a radial piston pump for energy saving pressure flow control. The pitch angle of the unwinding is easily adjustable and can be entered manually or remotely. As with other paper core designs, the UBR paper core machine is powered by a servo motor for easy changing rates and high cycle times.
A mailing tube is a sturdy, solid, and durable cardboard container designed for shipping long slender devices and products or rolled up maps, banners, and posters. The indestructible exterior of mailing tubes...
A poster tube is a cylindrical, triangular, or rectangular hollow prism that is commonly used to transport rollable, unframed art, important documents, or long and slender materials. They also carry objects like...
A shipping tube is a long container used for mailing long items that are rolled or folded to fit in the tube. They are constructed of various types of materials with Kraft paper being the most common and widely...
A Sonotube® is a cardboard concrete forming tube made of waxed paper or lamination that is wound into a tube into which concrete is poured to create supports, columns, and supports for posts. Sonotube® is a registered trademark owned by SPC RESOURCES, INC...
Pressure-sensitive adhesive tapes consist of a backing material film coated with an adhesive intended for relatively low-stress applications. Light pressure, usually done by the fingertips, is applied to initiate the binding. In the sticking process, the fluid properties...
A cardboard box is a shipping container made of thick heavy duty paper known as paperboard, which is more than 0.01 inch or 0.25 mm thick. The term cardboard is used as a generic descriptor for various types of solid firm papers used to produce boxes
Carpet tape is a double-sided tape designed for securing carpets or rugs to the floor. It's made of strong, durable, and adhesive material that can hold the carpet in place and prevent it from sliding or wrinkling. Carpet tape is used in
A corrugated box is a disposable container whose sides are made up of layers of material that include an inside layer, outer layer, and middle layer. The middle layer, between the outer and inner layers, is fluted, which are rigid wave shaped arches that provide cushioning...
One kind of pressure-sensitive self-adhesive tape is foam tape. It has one of several different backing materials and is made of foam. It may have adhesive on one or both sides. Foam tapes are, at their most basic level, tapes that are applied to uneven or
Masking tape is pressure sensitive, thin and very adhesive, easy to tear paper that is used in various tasks ranging from masking off areas that are not to be painted or as insulation for electric wires among other...
PTFE stands for polytetrafluoroethylene and is a synthetic fluoropolymer used widely in many industries and many other applications. PTFE is also commonly referred to as thread seal tape, teflon tape, and plumber‘s tape...