Paper Production and History Quiz

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Questions and Answers

What is the primary raw material used in the production of paper today?

Wood pulp (correct)

Hemp

Bamboo

Cotton

Who is credited with the invention of paper in 105 AD?

The ancient Egyptians

Mahatma Gandhi

Ts'ai Lun (correct)

Confucius

Which type of trees provides the majority of wood pulp used in paper production?

Fruit trees

Deciduous trees

Coniferous trees (correct)

Citrus trees

What was the original writing material used by the ancient Egyptians?

Papyrus Signup and view all the answers

For how long was the fabrication of paper monopolized by the Chinese Empire?

500 years Signup and view all the answers

What is the primary purpose of the beating and refining stage in the paper making process?

To improve the bonding potential and physical properties of the finished sheet. Signup and view all the answers

During the paper making process, what proportion of the slurry consists of fibers?

1% Signup and view all the answers

What effect does beating have on the fibers during the paper making process?

It increases the surface area and enhances water absorption. Signup and view all the answers

What is one result of the improved inter-fiber bonding due to beating?

Increased flexibility of the fibers. Signup and view all the answers

What role does dilution with water play in the paper making process?

It creates a slurry that facilitates fiber manipulation. Signup and view all the answers

What is the main objective of the pulping process?

To produce well-cooked pulp free from non-cellulosic portions Signup and view all the answers

What is the purpose of the bleaching process in pulp production?

To remove lignin that discolors the final paper Signup and view all the answers

What is a consequence of the bleaching process on pulp?

Reduces the strength of the pulp while increasing brightness Signup and view all the answers

Which agents are used in the bleaching of mechanical pulps?

Chlorine dioxide and ozone Signup and view all the answers

What factor contributes significantly to the brown color of pulp?

Chromophoric groups on lignin Signup and view all the answers

Which characteristic is true of chemical pulp processing?

It focuses on removing remaining lignin for whiteness Signup and view all the answers

At what temperature does the bleaching process requiring three hours typically occur?

40°C Signup and view all the answers

What compromises must be considered during the bleaching process?

Maintaining strength while reducing lignin and achieving brightness Signup and view all the answers

What is the primary purpose of sizing agents in paper making?

To enhance fiber bonding and physical properties Signup and view all the answers

Which process is responsible for reorienting surface fibers in paper?

Calendering Signup and view all the answers

What effect do barrier coatings have in packaging?

They prevent gases and water vapor from penetrating Signup and view all the answers

Which of the following is NOT a function of pigments in paper making?

To form a barrier against moisture Signup and view all the answers

What type of emulsions are ideally suited for food packaging adhesion?

Acrylic-based emulsions Signup and view all the answers

What is the main purpose of calendering in the paper making process?

To achieve a smooth surface and glossy finish Signup and view all the answers

What roles do adhesives play in the paper making process?

To bind pigment particles and enhance surface properties Signup and view all the answers

Sizing agents impact the paper's resistance to which of the following?

Water and moisture Signup and view all the answers

What effect does adding TiO2 have on paper?

Improves opacity Signup and view all the answers

What is the minimum thickness of paperboard products?

0.2 mm Signup and view all the answers

Which component is NOT suitable for food contact purposes?

Post-consumer waste papers Signup and view all the answers

What type of coating provides a moisture barrier in paperboard products?

Wax lamination Signup and view all the answers

What is the primary function of the corrugated layer in paperboard packaging?

Protect food from surroundings Signup and view all the answers

Which type of carton structure is commonly used for aseptic packaging?

Brick-shaped cartons Signup and view all the answers

What type of process is used to produce egg cartons from an aqueous slurry?

Suction molding Signup and view all the answers

What is a feature of dual-ovenable containers?

Compatible with both microwave and convection ovens Signup and view all the answers

What is a primary characteristic of kraft paper?

It can be wet-strengthened or made water-repellant. Signup and view all the answers

Which type of paper is specifically treated to give oil and grease resistance?

Greaseproof paper Signup and view all the answers

What is the main function of waxed paper?

To serve as a good barrier against moisture and heat. Signup and view all the answers

What property makes vegetable parchment suitable for wet and greasy foods?

High wet strength Signup and view all the answers

Which paper type is noted for its glassy and transparent surface?

Glassine paper Signup and view all the answers

How is the adhesion and performance of wet waxed paper enhanced?

By adding special resins or plastic polymers to the wax. Signup and view all the answers

What is a drawback of greaseproof paper?

It may allow oils and fats to penetrate over time. Signup and view all the answers

What characteristic does not apply to waxed paper?

It provides a poor barrier against moisture. Signup and view all the answers

Study Notes

Paper and Paperboard Packaging Materials

Paper is a substance made from thin sheets, often from rags, straw, bark, wood or other fibrous materials
Paperboard is thicker than paper (>0.25mm)
Paper was first produced in Egypt around 900 AD.
Ts'ai Lun, in China, invented paper using mulberry bark, hemp, and rags in 105 AD.
The Chinese Empire monopolised paper production for over 500 years.
Currently, 97% of paper and board globally are made from wood pulp.
85% of the wood pulp comes from spruces, firs, pine (coniferous trees), and oak trees.
Other plants used in paper making include cotton, bamboo, and kenaf.

Manufacturing of Paper

Pulp process: pulping; digestion, bleaching; and converting.
Paper making process: beating and refining; papermaking (pulp in water slurry); converting (additional treatment)

Pulp Process

Pulping methods include mechanical, chemical, and semi-chemical.
Mechanical pulping: uses grindstones to physically separate fibres to produce pulp, with intact lignin, suitable for lower quality products like newsprint, tissues, and paperboard for folding. Has high yield, low cost but low mechanical strength.
Thermomechanical Pulping: Pre-steam wood chips between 110 and 150°C becomes malleable.
Chemical pulping: uses chemicals to remove lignin (like NaOH and sodium sulfide), yielding higher quality pulp suitable for paper stronger suited for food, packaging.
Semi-chemical pulping: mix of mechanical and chemical methods.

Digestion Process

Treating wood in chip form in a pressurized vessel under controlled conditions (time, liquor concentration, pressure, temperature).
Objectives: Produce well-cooked pulp, free from non-cellulosic portions of the wood (lignin and hemicellulose) to achieve maximum yield of raw material (wood pulp).

Bleaching Process

Aims to remove lignin for discolouration of final paper.
Bleaching agents vary in use with various processes for varying strengths of the final pulp.
Some agents are hydrogen peroxide (H2O2) and sodium peroxide (alkaline solution).

Paper Making Process

Beating and Refining: mechanically treats fibres to improve their bonding potential, flexibility and strength.
Papermaking: creates a slurry by diluting the pulp with water.
Converting: further treatment.

Paper Making Techniques

Fourdrinier machine: used to produce all grades of paper and paperboard.
Cylinder Machine: used to produce heavy multi-ply boards.
Twin-Wire Formers: designed to produce sheets fast.
Presses and Dryers: sheets (75% to 90% moisture) pass through presses and dryers to further remove water.

Converting

Further surface treatment involves applying adhesives, functional products (e.g. pigments), barrier coatings, e.t.c. This depends on the final use of the paper.

Calendering

Reorients fibres in the base sheet using pressure, creating a smooth surface, control surface texture, and a glossy finish.

Sizing and Coating

Added agents increase fiber bonding, improve strength, help with water resistance, and prevent excess water penetration and improve paper strength.

Adhesives

Binds pigment particles to the raw stock.
Various types include starches, casein, soy proteins, and rubber latex.
Acrylic-based emulsions are useful for food packaging.

Barrier Coatings

Many packaging applications require a barrier preventing water vapor and gases.
Creating a water barrier is done by changing paper surface wettability with sizing agents.
Examples: paraffin wax and polyethylene.

Pigments

Mask or change the appearance of the base stock.
Improve opacity and impart a smooth surface for printing.
Examples include kaolin clay, calcium carbonate, and a combination of PS-based plastic pigments and mineral pigments.

Types of Paper, Properties, and Uses

Kraft paper: coarse, heavy duty, bleached, natural, or coloured. Used for bags, multiwall and corrugated box liners.
Greaseproof paper: translucent, hydrated to resist oil and grease. Used for butter, baked goods and high fat food packaging.
Vegetable parchment: Non-toxic, high wet strength, free of lint, suitable for wet and greasy food. Uses include interleaver, labels, inserts
Waxed paper: moisture barrier and heat-sealable. Made from waxing base paper (like greaseproof or glassine).
Glassine paper: smooth, glossy, high density, and transparent.
Paperboard Products: Generally >224 g/m2, thickness between 0.2–1.0mm, and weight/surface area that ranges from 120-700 g/m2.
Folding carton: sheets of paperboard. Coating and laminating can create barrier properties as needed.
Beverages carton: Layers of bleached and unbleached paperboard with an LDPE coating.
Molded pulp carton: 3D packaging, formed from aqueous slurry of fibres onto screened moulds.
Corrugated cardboard: layers to protect from impact.

Advantages and Disadvantages of Paper Packaging

Advantages: superior printability, easy processing, appropriate stiffness, lightweight, cheap, mechanical strength, and biodegradable.
Disadvantages: naturally poor properties (porous, opaque, low moisture/gas/oil resistance), doesn't prevent flavour loss from food, and cannot be heat sealed.

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Description

Test your knowledge on the production of paper, its historical origins, and the processes involved in its creation. This quiz covers everything from the raw materials used to the techniques of refining and bleaching pulp. Dive into the fascinating world of paper making!