Pulp & Paper Questions and Answers – Functional Additives

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This set of Pulp and Paper Interview Questions and Answers for Experienced people focuses on “Functional Additives”.

1. Fillers are pigments that are not added to stock for opacity and brightness improvements of printing papers.
a) True
b) False
View Answer

Answer: b
Explanation: Fillers are pigments that are added to stock for opacity and brightness improvements of printing papers.
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2. The ideal properties of pigments for printing papers are of high brightness, and high index of refraction.
a) True
b) False
View Answer

Answer: a
Explanation: The ideal properties of pigments for printing papers are high brightness, and increment in opacity, small and uniform particle size for smooth paper, low water solubility, low cost, low specific gravity, and high retention levels.

3. __________ is a cheap filler, mined from natural deposits, used in magazine and book paper. It’s not as bright as CaCO3 and TiO3, has an index of refraction of 1.55.
a) PCC
b) Fillers
c) Clay
d) Dyes
View Answer

Answer: c
Explanation: Clay (or kaolin) is an inexpensive filler, mined from natural deposits, used in magazine and book paper. It’s not as bright (80-92%) as CaCO3 and TiO3, has an index of refraction of 1.55, a specific gravity around 2.58, and is coarse. More clay’s used than any other filler in paper accounting for 90 percent of all fillers and coating pigments.

4. __________ is becoming an extremely imp. filler to the industry. The mineral form’s named calcite and occurs in limestones, chalks, and marbles.
a) Dyes
b) Clay
c) Fillers
d) Chalk
View Answer

Answer: d
Explanation: CaCO3 {chalk or limestone) is becoming an extremely important filler to the industry. The mineral form’s named calcite and occurs in limestones, chalks, marbles, and other forms, because it reacts with HCl to give CaCl2 and CO2, it must be utilized in alkaline papermaking systems at pH 7.0 or greater.

5. __________ is an expensive filler which costs greater than bleached pulp and is very bright. It has a high index of refraction and a particle size (typically only 0.20 to 0.25 film) that both contribute to high opacity.
a) Chalk
b) Kaolin
c) Titanium dioxide
d) Dyes
View Answer

Answer: c
Explanation: TiO2 is an expensive filler which costs slightly more than bleached pulp and is very bright (98%). It has a high index of refraction (2.56-2.70) and a particle size (typically only 0.20 to 0.25 film) that both contribute to high opacity. It’s also utilized in most white paints as the pigment.
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6. __________ is used as a filler in Europe. Diatomaceous earth’s generally utilized for pitch control. Some other fillers are utilized, including ZnO2 and calcium sulfate.
a) Talc
b) Titanium dioxide
c) Clay
d) Calcium carbonate
View Answer

Answer: a
Explanation: Talc which is hydrated magnesium silicate, refractive index of 1.57, brightness of 90-95 percentage, specific gravity of 2.7, particles 0.5-5 jLtm is utilized in the U.S. mostly as a pitch control agent; it’s utilized as a filler in Europe. Diatomaceous earth’s normally used for pitch control. Some other fillers are utilized, including ZnO2 and calcium sulphate.

7. __________ are water soluble colours added to stock which impart color to the final product then __ are absorbed on the fiber surfaces imparting their colours to the paper fibers.
a) Talc
b) Clay
c) Dyes
d) Brighteners
View Answer

Answer: c
Explanation: Dyes are water soluble colours added to stock to impart colour to the final product. Dyes are absorbed on the fiber surfaces releasing their colours to the paper fibers. They have structures involving large conjugated double bond systems with azo, metallic azo, anthraquinone, triarylmethane, quinoline, and similar structures.

8. Basic dyes are cationic organic dyes which contain amine groups and are utilized with inorganic anions to fix them to the surface of __________
a) Clay
b) Dyes
c) Fibers
d) Brighteners
View Answer

Answer: d
Explanation: Basic dyes are cationic organic dyes which contain amine groups which are utilized with inorganic anions to fix them to the surface of fibers. They have strong affinity for lignin but not for bleached pulps and have poor fastness to light. They are utilized in newsprint, in “yellow pages” of phone books, and similar products.

9. __________ is the third most crucial paper furnish based on the weight utilized, with pulp and clay. It’s utilized as a retention aid, dry strength agent, and surface sizing agent.
a) Starch
b) Clay
c) Dyes
d) Titanium oxide
View Answer

Answer: a
Explanation: Starch is the 3rd most crucial paper furnish based on the weight used, with pulp and clay. It’s utilized as a retention aid, dry strength agent, coating binder, and adhesive in corrugated board and other converting operations. There are 2 types of starch: amylose and amylopectin.

10. A useful conversion for D.S. from % nitrogen for nitrogen contents below about 5 % nitrogen (0.5% N = D.S. 0.06) is:

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D.S. = __________ X Percent Nitrogen

Cationic starches are utilized to help form stable emulsions from A.S.A. and A.K.D. sizing agents.
a) 0.112
b) 0.117
c) 0.115
d) 0.120
View Answer

Answer: b
Explanation: A useful conversion for D.S. from % nitrogen for nitrogen contents below about 5 % nitrogen (0.5% N = D.S. 0.06) is: D.S. = 0.117 X Percent Nitrogen Cationic starches are utilized to help form stable emulsions from A.S.A. and A.K.D. sizing agents.

Sanfoundry Global Education & Learning Series – Pulp and Paper.
To practice all areas of Pulp and Paper for Interviews, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn