Coated paper

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PE Coated Cupstock Jumbo Roll From Jota Machinery PE Coated Paper.jpg
PE Coated Cupstock Jumbo Roll From Jota Machinery

Coated paper (also known as enamel paper, gloss paper, and thin paper [1] ) is paper that has been coated by a mixture of materials or a polymer to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absorbency. Various materials, including kaolinite, calcium carbonate, bentonite, and talc, [2] can be used to coat paper for high-quality printing used in the packaging industry and in magazines.

Contents

The chalk or china clay is bound to the paper with synthetic viscosifiers, such as styrene-butadiene latexes and natural organic binders such as starch. The coating formulation may also contain chemical additives as dispersants, resins, or polyethylene to give water resistance and wet strength to the paper, [3] or to protect against ultraviolet radiation.

Coated papers have been traditionally used for printing magazines. [4]

Varieties

Machine-finished coated paper

Machine-finished coated paper (MFC) has a basis weight of 48–80 g/m2. They have good surface properties, high print gloss and adequate sheet stiffness. MFC papers are made of 60–85% groundwood or thermomechanical pulp (TMP) and 15–40% chemical pulp with a total pigment content of 20–30%. The paper can be soft nip calendered or supercalendered. [5] These are often used in paperbacks.

Coated fine paper

Coated fine paper or woodfree coated paper (WFC) are primarily produced for offset printing: [6]

Standard coated fine papers
This paper quality is normally used for advertising materials, books, annual reports and high-quality catalogs. Grammage ranges from 90–170 g/m2 and ISO brightness between 80–96%. The fibre furnish consists of more than 90% chemical pulp. Total pigment content are in the range 30–45%, where calcium carbonate and clay are the most common.
Low coat weight papers
These paper grades have lower coat weights than the standard WFC (3–14 g/m2/side) and the grammage and pigment content are also generally lower, 55–135 g/m2 and 20–35% respectively.
Art papers
Art papers are one of the highest-quality printing papers and are used for illustrated books, calendars and brochures. The grammage varies from 100 to 230 g/m2. These paper grades are triple coated with 20–40 g/m2/side and have matte or glossy finish. Higher qualities often contain cotton.

Plastic coatings

Plastic-coated paper includes types of paper coatings; polyethylene or polyolefin extrusion coating, silicone, and wax coating to make paper cups and photographic paper. Biopolymer coatings are available as more sustainable alternatives to common petrochemical coatings like low-density polyethylene (LDPE) or mylar. [7] It is most used in the food and drink packaging industry.

The plastic is used to improve functions such as water resistance, tear strength, abrasion resistance, ability to be heat sealed, etc. Some papers are laminated by heat or adhesive to a plastic film to provide barrier properties in use. Other papers are coated with a melted plastic layer: curtain coating is one common method. Printed papers commonly have a top coat of a protective polymer to seal the print, provide scuff resistance, and sometimes gloss. Some coatings are processed by UV curing for stability.

Most plastic coatings in the packaging industry are polyethylene (LDPE) and to a much lesser degree PET. Liquid packaging board cartons typically contain 74% paper, 22% plastic and 4% aluminum. Frozen food cartons are usually made up of an 80% paper and 20% plastic combination. [8]

The most notable applications for plastic-coated paper are single use (disposable food packaging): [9]

Plastic coatings or layers usually make paper recycling more difficult. Some plastic laminations can be separated from the paper during the recycling process, allowing filtering out the film. [10] [11] If the coated paper is shredded prior to recycling, the degree of separation depends on the particular process. Some plastic coatings are water dispersible to aid recycling and repulping. Special recycling processes are available to help separate plastics. [12] [13] [14] Some plastic coated papers are incinerated for heat or landfilled rather than recycled.

Most plastic coated papers are not suited to composting, [15] but do variously end up in compost bins, sometimes even legally so. In this case, the remains of the non-biodegradable plastics components form part of the global microplastics waste problem. [9]

Others

Printed papers commonly have a top coat of a protective polymer to seal the print, provide scuff resistance, and sometimes gloss. Some coatings are processed by UV curing for stability.

A release liner is a paper (or film) sheet used to prevent a sticky surface from adhering. It is coated on one or both sides with a release agent.

Heat printed papers such as receipts are coated with a chemical mixture, which often contains estrogenic and carcinogenic poisons, such as bisphenol A (BPA). It is possible to check whether a piece of paper is thermographically coated, as it will turn black from friction or heat. (see Thermal paper)

Paper labels are often coated with adhesive (pressure sensitive or gummed) on one side and coated with printing or graphics on the other.

See also

Related Research Articles

<span class="mw-page-title-main">BoPET</span> Polyester film

BoPET is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical stability, dimensional stability, transparency reflectivity, and electrical insulation.. When metallized, it has gas and moisture barrier properties, The film is "biaxially oriented", which means that the polymer chains are oriented parallel to the plane of the film, and therefore oriented in two axes. A variety of companies manufacture boPET and other polyester films under different brand names. In the UK and US, the best-known trade names are Mylar, Melinex, Lumirror and Hostaphan. It was the first biaxially oriented polymer to be manufactured on a mass commercial scale.

<span class="mw-page-title-main">Paperboard</span> Thick paper-based material

Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker than paper and has certain superior attributes such as foldability and rigidity. According to ISO standards, paperboard is a paper with a grammage above 250 g/m2, but there are exceptions. Paperboard can be single- or multi-ply.

<span class="mw-page-title-main">Lamination</span> Technique of fusing layers of material

Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materials, such as plastic. A laminate is a layered object or material assembled using heat, pressure, welding, or adhesives. Various coating machines, machine presses and calendering equipment are used.

<span class="mw-page-title-main">Carton</span> Type of domestic container

A carton is a box or container usually made of liquid packaging board, paperboard and sometimes of corrugated fiberboard. Many types of cartons are used in packaging. Sometimes a carton is also called a box.

<span class="mw-page-title-main">Calender</span> Series of hard pressure rollers that produces a surface effect on fabric, paper, or plastic film

A calender is a series of hard pressure rollers used to finish or smooth a sheet of material such as paper, textiles, rubber, or plastics. Calender rolls are also used to form some types of plastic films and to apply coatings. Some calender rolls are heated or cooled as needed. Calenders are sometimes misspelled calendars.

<span class="mw-page-title-main">Label</span> Material affixed to a container or article with printed information

A label is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product, on which is written or printed information or symbols about the product or item. Information printed directly on a container or article can also be considered labelling.

<span class="mw-page-title-main">Paper bag</span> Open-end flexible container made of paper

A paper bag is a bag made of paper, usually kraft paper. Paper bags can be made either with virgin or recycled fibres to meet customers' demands. Paper bags are commonly used as shopping carrier bags and for packaging of some consumer goods. They carry a wide range of products from groceries, glass bottles, clothing, books, toiletries, electronics and various other goods and can also function as means of transport in day-to-day activities.

<span class="mw-page-title-main">Kraft paper</span> Paper or paperboard produced from chemical pulp produced in the kraft process

Kraft paper or kraft is paper or paperboard (cardboard) produced from chemical pulp produced in the kraft process.

<span class="mw-page-title-main">Blister pack</span> Type of packaging

A blister pack is any of several types of pre-formed plastic packaging used for small consumer goods, foods, and for pharmaceuticals.

In-mould labelling is the use of paper or plastic labels during the manufacturing of containers by blow molding, injection molding, or thermoforming processes. The label serves as the integral part of the final product, which is then delivered as pre-decorated item. Combining the decoration process with the moulding process cuts the total cost, but can increase the manufacturing time. The technology was first developed by Owens-Illinois in cooperation with Procter & Gamble to supply pre-labelled bottles that could be filled on the product filling line. This was first applied to Head & Shoulders shampoo bottles.

<span class="mw-page-title-main">Paper cup</span> Cup mostly made of paper or card

A paper cup is a disposable cup made out of paper and often lined or coated with plastic or wax to prevent liquid from leaking out or soaking through the paper. It may be made of recycled paper.

<span class="mw-page-title-main">Inkjet paper</span> Paper designed for use with inkjet printers

Inkjet paper is a special fine paper designed for inkjet printers, typically classified by its weight, brightness and smoothness, and sometimes by its opacity.

<span class="mw-page-title-main">Plastic bottle</span> Narrow-necked container

A plastic bottle is a bottle constructed from high-density or low density plastic. Plastic bottles are typically used to store liquids such as water, soft drinks, motor oil, cooking oil, medicine, shampoo or milk. They range in sizes, from very small bottles to large carboys. Consumer blow molded containers often have integral handles or are shaped to facilitate grasping.

Metallised films are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost. Metallised films are widely used for decorative purposes and food packaging, and also for specialty applications including insulation and electronics.

Deinking is the industrial process of removing printing ink from paperfibers of recycled paper to make deinked pulp.

<span class="mw-page-title-main">Liquid packaging board</span>

Liquid packaging board is a multi-ply paperboard with high stiffness, strong wet sizing and a high barrier coating, e.g. plastic. Only virgin paper fibers are used. The barrier coating must hold the liquid and prevent migration of air and flavors through the paperboard.

<span class="mw-page-title-main">Disposable food packaging</span>

Disposable food packaging comprises disposable products often found in fast-food restaurants, take-out restaurants and catering establishments. Typical products are foam food containers, plates, bowls, cups, utensils, doilies and tray papers. These products can be made from a number of materials including plastics, paper, bioresins, wood and bamboo.

The wet strength of paper and paperboard is a measure of how well the web of fibers holding the paper together can resist a force of rupture when the paper is wet. Wet strength is routinely expressed as the ratio of wet to dry tensile force at break.

<span class="mw-page-title-main">Retort pouch</span> Type of food packaging

A retort pouch or retortable pouch is a type of food packaging made from a laminate of flexible plastic and metal foils. It allows the sterile packaging of a wide variety of food and drink handled by aseptic processing and is used as an alternative to traditional industrial canning methods. Retort pouches are used in baby and toddler food, camping food, field rations, fish products, instant noodles, space food sports nutrition and brands such as Capri-Sun and Tasty Bite.

<span class="mw-page-title-main">Multilayered packaging</span>

Multi-layered packaging are multilayer or composite materials using innovative technologies aimed to give barrier properties, strength and storage stability to food items, new materials as well as hazardous materials.

References

  1. Mark Beach (1993). Getting it Printed . North Light Books. p.  178. ISBN   978-0-89134-510-7. Book paper is divided into uncoated paper (also called offset paper), coated paper (also called art paper, enamel paper, gloss paper and slick paper) and text paper.
  2. "Grades of Paper". paperonweb.com.
  3. Diana Twede and Susan E. M. Selke (2005). Cartons, crates and corrugated board: handbook of paper and wood packaging technology. DEStech Publications. p. 325. ISBN   978-1-932078-42-8.
  4. "How to buy paper for magazines". holmen.com. Retrieved 10 October 2023.
  5. Paulapuro, Hannu (2000). "1". Paper and Board grades. Papermaking Science and Technology. Vol. 18. Finland: Fapet Oy. p. 35. ISBN   978-952-5216-18-9.
  6. Paulapuro, Hannu (2000). "1". Paper and Board grades. Papermaking Science and Technology. Vol. 18. Finland: Fapet Oy. pp. 38–39. ISBN   978-952-5216-18-9.
  7. Khwaldia, Khaoula; Elmira Arab-Tehrany; Stephane Desobry (2010). "Biopolymer Coatings on Paper Packaging Materials". Comprehensive Reviews in Food Science and Food Safety. 9 (1): 82–91. doi: 10.1111/j.1541-4337.2009.00095.x . PMID   33467805.
  8. "Recycling Mystery: Milk and Juice Cartons". earth911.com. 14 November 2018.
  9. 1 2 "Should Plastic-Coated Paper Products be Allowed in Materials Collected for Composting?" (PDF). EcoCycle. Archived from the original (PDF) on 27 April 2017.
  10. Jensen, Timothy (April 1999). "Packaging Tapes:To Recycle of Not". Adhesives and Sealants Council. Archived from the original on 9 November 2007. Retrieved 6 November 2007.
  11. Gruenewald, L. E.; Sheehan, R. L. (1997). "Consider box closures when considering recycling". J. Applied Manufacturing Systems. 9 (1). St Thomas Technology Press: 27–29. ISSN   0899-0956.
  12. 5084135 A US US 5084135 A,/Brooks, Joe,"Recycling plastic coated paper product waste",published 28 January 1992
  13. 5,277,758 US US 5,277,758,Brooks, J G,"Method for recycling plastic coated paper product waste and polymeric film JG Brooks, BD Goforth, CL Goforth... - US Patent 5,277,758, 1994",published 11 January 1994
  14. 5865947 A US US 5865947 A,Markham, L D,"Method for recycling mixed wastepaper including plastic-containing paper and ink printed paper",published 2 February 1999
  15. R. McKinney: Technology of Paper Recycling, 1995, p. 351. ISBN   9780751400175

Further reading