This set of Food Packaging Technology Multiple Choice Questions & Answers (MCQs) focuses on “Paper Making – 1”.
1. __________ is the interface between the pulp mill and the papermaking process.
a) Stew preparation
b) Stock preparation
c) Dew preparation
d) Stall preparation
View Answer
Explanation: Stock preparation is the interface between the pulp mill and the papermaking process in which pulp is treated mechanically and, in some instances, chemically by the use of additives and is thus made ready for forming into a sheet or board on the paper machine. During the stock preparation steps, the pulps are most conveniently handled as aqueous slurries.
2. The separation of all the fibers from one another and their dispersion in water is called ________
a) Slushing
b) Sheeting
c) Wetting
d) Mashing
View Answer
Explanation: The separation of all the fibers from one another and their dispersion in water is called slushing or repulping. In the papermaking process utilizing purchased pulps and waste paper which are received as dry sheets, the first step is the separation of all the fibers from one another, and their dispersion in water with a minimum of mechanical work to avoid altering the fiber properties. This process is known as slushing or repulping and is carried out in a machine such as the hydrapulper, so called because of the hydraulic forces that are developed. When the pulping and papermaking operations are adjacent to one another, pulps are usually delivered to the paper mill in slush form directly from the pulping operation.
3. Stock (fibrous material) is prepared by which of the following processes?
a) Extraction and expelling
b) Beating and extraction
c) Extraction and refining
d) Beating and refining
View Answer
Explanation: Stock—as fibrous material is commonly called—is prepared by two chief processes commonly referred to as beating and refining. Both operations are fundamentally the same; in many situations, the two terms are used synonymously. Beating and refining are used to improve the strength and other physical properties of the finished sheet, and to influence the behavior of the system during the sheet-forming and drying steps.
4. The object of beating is _________ of the fibers by assisting them to imbibe water.
a) To increase the surface area
b) To decrease the surface area
c) To increase the volume
d) To decrease the volume
View Answer
Explanation: The object of beating is to increase the surface area of the fibers by assisting them to imbibe water. As a result, additional bonding opportunities are provided for between cellulose molecules of neighboring fibers.
5. After beating, the mixture of pulp is brought to a consistency of ______
a) 3%–5%.
b) 1%–7%.
c) 5%–7%.
d) 6%–9%.
View Answer
Explanation: The mixture of pulp (known as the furnish) is passed into the beater and brought to a consistency of 5%–7%. The beating makes the fibers more flexible, causing them to become relatively mobile and to deform plastically on the paper machine.
6. An unbeaten pulp has a low density.
a) True
b) False
View Answer
Explanation: The given statement is true. Because papermaking fibers are stiff and springy, the resulting paper would be flabby and weak if made into a sheet of paper without beating. There would be little adhesion between the fibers and they could not be consolidated under the presses of the paper machine. A sheet formed from an unbeaten pulp has a low density, and is rather soft and weak.
7. Extreme beating produces very dense, translucent, glassine-type sheets.
a) True
b) False
View Answer
Explanation: The given statement is true. If the same unbeaten pulp is beaten, then the resultant paper is much more dense, hard and strong. If taken to the extreme, beating produces very dense, translucent, glassine-type sheets. Thus, beating can be controlled to produce paper types as widely different as blotting and greaseproof paper.
8. In many paper mills, beaters have been replaced by ________
a) Continuous refiners
b) Continuous disks
c) Continuous sheets
d) Continuous templates
View Answer
Explanation: In many paper mills, beaters have been replaced by continuous refiners, such as disk refiners (where rotary disks rotate against a working surface) and conical refiners. However, the batch beater is a convenient vessel for adding chemicals and mixing them intimately with the pulp in order to give special properties to the final paper.
9. Which of the following is not a filler used in paper?
a) Titanium dioxide
b) Sodium hydroxide
c) Kaolin clay
d) Calcium carbonate
View Answer
Explanation: Sodium hydroxide is not a filler used in paper. Calcium carbonate is the most important papermaking filler followed by kaolin clay, with limited use of titanium dioxide. Fillers can improve brightness, opacity, softness, smoothness and ink receptivity, and are essentially insoluble in water under the conditions of use. Filler particles are often 0.5 to 3 mm in diameter, which is much smaller than the fibers used in making paper. Hence, fillers help in making the paper smooth. Not only this, fillers also increase papers’ opacity and brightness as it increases light scattering efficiency.
10. Which of the following is used to increase water resistance of paper?
a) Filling
b) Sizing
c) Stretching
d) Sheeting
View Answer
Explanation: Sizing is the process of adding materials to the paper in order to render the sheet more resistant to penetration by liquids, particularly water. Rosin is the most widely used sizing agent, but starches, glues, caseins, synthetic resins and cellulose derivatives are also used. The sizing agents may be added directly to the stock as beater additives to produce internal or engine sizing.
11. Resistance of paper against water is called wet-strength.
a) True
b) False
View Answer
Explanation: The given statement is true. The required wet strength (up to 50% of the dry paper strength can be retained) is obtained with the aid of wet-strength additives that are capable of covalently bonding in order to preserve paper strength in the presence of water. Linerboard, carrier board, bleached carton and liquid paperboard are some of the principal grades that require an amount of wet strength to be functional.
Sanfoundry Global Education & Learning Series – Food Packaging Technology.
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