“Develop success from failures. Discouragement and failure are two of the surest stepping stones to success.”
SUBSTRATE FOR PRINTING
PAPER: Paper word derived from Greek ‘papyrous’ which is the name of a tree. It Is invented to TS’ai lun of china in the year 105A.D.
Paper consists of a compact web, of felting of vegetable fibres, usually in the form a thin flexible sheet.
Nature of paper
Raw material used: Two material used while paper make:
1. Fibers material
2. Non-Fibrous material
Fibrous: cellulose fiber can be regarded as the common building brick of the tree. In a few material like cotton and linen, the cellulose exists in a purer form.
Fibers have the form of long usually hollow tubes. This range in length from 1 to 7.50mm and width from 0.01 to 0.05mm according to the plant in which they occur. Cellulose made of carbon, hydrogen and oxygen.
1. Cotton fibers: it is second hair of the cotton plant of natural cellulose. It is used in high grade writing, currency and legal paper.
2. Linen: it is obtained from the ring of last tissues of the stem of the flax plant but as with cotton. It is used in thin strong paper like bank notes and air mill paper.
3. Wood: wood pulp is spruce, pine, deciduous, aspen, eucalytus, birch are some of the material are mix and clean and make white bulky opaque and uniform sheet for printing paper.
A pure form of wood cutting and subjecting it to chemical treatment and remove the natural gums and resin leaving a soft pure pulp.
It is made of mechanical pulp in found dust and doing grinding process by left impurities and make a less strength and poor color paper.
4. Sparto grass: it is found North-Africa and Spain. It is made good writing paper.
5. Straw: it is stem of the wheat, it is made writing paper like bank and bond paper and high bursting strength.
6. Manila: it is found from Phillipine Island and used in wrapping tissue Cigrette paper and bank note.
7. Jute: it is tissues of annual Indian plant and shorter than linen and hamp used in the thin wrapping.
8. Ramie and china-grass: it is used in Bible paper.
9. Bagasse: it obtains from sugarcane and used in corrugated paper and board.
Non-fibrous material: like chemicals
1. Filler and loader: it is used for strength and optical agent.
a. Strength:- (tensile strength, bursting strength, tearing strength)
b. Optical agent: (brightness, opacity, reflectance).
2. Sizing agent
Introduction to Recycled Paper
Recycled paper is paper made from recovered waste paper instead of fresh wood pulp. It helps in:
Types of Recycled Paper:
1. Post-consumer waste – Paper used and discarded by consumers (newspapers, magazines).
2. Pre-consumer waste – Paper scraps generated during manufacturing processes.
2. Recycling Process of Paper
The process of converting waste paper into recycled paper involves several steps:
1. Collection – Waste paper is collected from homes, offices, and industries.
2. Sorting – Paper is sorted based on type, grade, and color.
3. Shredding / Pulping – Paper is shredded and mixed with water to make pulp.
4. De-inking – Ink, adhesives, and contaminants are removed using chemicals or flotation.
5. Cleaning and Screening – Fibers are cleaned of impurities like plastics, staples, and dirt.
6. Bleaching (Optional) – Pulp is whitened if required.
7. Refining and Beating – Pulp fibers are treated to improve bonding and smoothness.
8. Sheet Formation – Pulp is spread on screens to form paper sheets.
9. Pressing and Drying – Water is removed; sheets are pressed and dried.
10. Finishing – Surface treatment, coating, and cutting into required sizes.
3. Fibre Preparation
Fibre preparation is a critical step for quality paper. It involves:
1. Pulp Refining – Improves fiber bonding and smoothness.
2. Beating / Mechanical Treatment – Increases flexibility and strength of fibers.
3. Blending – Mixing recycled fibers with virgin fibers to enhance strength (optional).
4. Consistency Adjustment – Ensuring uniform fiber distribution in the pulp.
4. Applications of Recycled Paper
Recycled paper is used in:
5. Printing Processes for Paper Printing
Several printing methods are compatible with recycled paper:
1. Offset Lithography – Most common method for newspapers, books, and brochures.
2. Gravure Printing – For high-quality packaging, magazines, and decorative printing.
3. Flexography – Used for packaging, cartons, and corrugated sheets.
4. Screen Printing – Posters, signage, and craft printing.
5. Digital Printing – Short runs, personalized prints, and on-demand printing.
Note: Recycled paper may require careful selection of inks and coatings due to surface texture and absorbency differences.
Varieties of paper:
1. Newspaper print-absorbing ability, quick drying, 75% mechanical wood pulp only coarse-screen halftone, good bulk and opacity lacks strength, yellow and brittle color.
2. Mechanical printing paper: chemical wood pulp writing, paper, one side smooth and thinner.
3. Machine finished: high calendering.
4. Super calendered: suitable for 100 lines upto screen rulling, extra polish and smooth.
5. Wood-free-chemical wood pulp, good color for magazine, leaflets, Booklets, reports 135 GSM.
6. Bible paper: thin white opaque paper, it is made cotton or linen with sulphite, Tio2, china clay.
7. Antique paper: esparto sulphite & soda with up to 15% china clay, rough surface short fibre. It is available 70 to 90 GSM. It is not suitable for writing purpose.
8. Catridge paper: the surface is uneven but strong use for drawing and painting and screen printing. It is not use for halftone and multicolor.
9. Offset cartridge paper: non-fluffy paper, esparto, sulphite or soda with china clay, Tio2.
10. Art paper: fine halftone, art books, technical journal, pamphlets.
11. Chromo paper: one side coated, printing of labels, stickers, posters, book jackets.
12. Cast coated: paper have mirror like glossy, it is only used in USA.
13. Imitation art: not coated, writing paper.
14. Bond paper: matt surface, more opaque, not penetrate ink easily used for letter heading.
15. Ledger paper: strong and durable writing paper made rage and cellulose additives used in banks, it is light blue, light green, yellow, off-white
UNIT-2
Introduction to Paperboard
Paperboard is a thick, durable, and stiff paper material used primarily for packaging and structural applications. It is stronger and heavier than regular paper, typically >0.3 mm in thickness, making it suitable for boxes, cartons, and other packaging products.
Key Features:
2. Difference Between Paper and Paperboard
Feature
Paper
Paperboard
Thickness
Usually <0.3 mm
>0.3 mm
Strength
Less durable
High strength and rigidity
Use
Writing, printing, packaging light products
Packaging, cartons, structural applications
Surface Finish
Can be smooth or rough
Often coated or laminated for printing and protection
Flexibility
Flexible
Relatively stiff and rigid
3. Types of Paperboard
Paperboard is classified based on manufacturing, layers, or surface finish:
4. Applications of Paperboard
Some common paper and cardboard GSM below:
1. Carbon copy and airmail paper 25-40 GSM
2. Thin printing paper 28-60 GSM
3. Newsprint 36-60 GSM
4. Endless paper 40-170 GSM
5. Illustration printing and cardboard 55-400 GSM
6. Writing and type writer paper 60-90 GSM
7. Book paper 60-120 GSM
8. Uncoated offset paper and card 60-300 GSM
9. Art print paper 90-350 GSM
10. Post card board 150-300 GSM
11. Index board 190-400 GSM
12. Box board 200-500 GSM
Paper sizes ISO: ISO system of paper size in UK and EUROPE is the ISO standard. It have dimensions in mm and international standard paper size.
ISO sizes divided into 2 category: ISO have three series A, B, C series.
A=general printing purpose like stationery and publication.
B= posters and wall charts
C= envelops.
It is regular sub-divisions 1: under root 2 and proportion of sides.
1. Side proportion of metric size
2. Sub-division
It is used in India follower by the British. It have dimension in inch.
NAME OF PAPER
size in inch
size in mm
Small foolscap
13 ¼ X16 ½
337X419
Foolscap
12 ½ X 17
343X432
Post
15 ½ X 19
394X483
Crown
15 X 20
381X508
Small demy
15 ½ X 20
394X508
Large post
16 ½ X 21
419X524
Demy
17 ½ X 22 ½
445X572
Medium
18 X 23
457X584
Small royal
19 X 24
483X610
Royal
20 X 25
508X635
Royal elephant
20 X 27
508X686
Large royal
20 ½ X 27
521X686
Imperial
22 X 30
559X762
Test procedure: for paper and paper board
1. Paper grain: when the paper contact on heated when it is curl parallel to grain direction.
2. Grammage: Grammage is defined as the weight/mass per unit surface area of paperboard. The S.I metric unit in which grammage is expressed in grams/square meter (gsm).
3. Thickness
4. Bulk
Practical knowledge
1. Paper: Aim: check out GSM of paper according to requirement.
Sampling: draw out sample randomly as per sampling plan for paper and paper board.
Check sheets of 1-2 packets/pallets visually for loose particles, specks, spots, smoothness of top and back surface etc.
Test procedure: testing of paper and paper board should be done as per following.
1. Grammage: grammage is defined as the weight/mass per unit surface area of paper board. The S.I metric unit in which grammage is expressed in Grams/square meter (GSM).
Significance: most of paper is sold in accordance with its grammage and therefore grammage has great significance both to the consumer and the procedure in defining price. The value of many physical properties such as bursting strength, thickness and bulk interpreted and specified with regarded to grammage.
Apparatus: a weighing scale. It is a special sheet weighing device designed to weight test speciman of 500 square cm (i.e. 20cmX25cm) area current, when it is in use.
1. Template for preparing test speciman (20X25cm size).
2. A sharp cutting.
3. A hard surface such for cutting the sample.
Sampling & test speciman:-
1. Sampling to be done as per sampling plan shown as above.
2. Cut atleast 8-10 pieces of 25cmX20cm size from test speciman (1 each from no. of sample board taken) with the help of the template.
Procedure: check grammage one by one on the weighting scale.
Formula in CM: weight X 10000 / length X width.
Weight: 1.67 X 10000 / 10 X 10
Weight = 167 gms.
Formula in Meter: weight / length X width.
Report: report the grammage as arithmetic means of the value of the test speciman cut in grams/square meter. The range of maximum to minimum (i.e. specification) is also to be reported.
Acceptance creteria: it the value of grammage tested is not within the standard specification range i.e +/-5%, then the lot is liable to rejection.
However, the lot may be accepted within same condition after taking approval from QA (incharge).
2. Thickness (dial thickness guage):
Scope: this method described the procedure for measuring single sheet thickness and variation in single sheet thickness and combined board expect for kraft paper.
Definition: thickness of caliper of paper/ paper board as measured by this method is defined as the perpendicular distance between the two principle surface of the paper board under pressureribed conditions.
Significance: variation in thickness can create lots of problems during printing and punching of cartons. The print transfer form blanket to surface will be improper. The crease will be shallow at some place and deep at other place. Variation in thickness may be resulted into rough cutting problem during punching.
Apparatus: a handy dial thickness gauge having 1cm or 0.01mm least count.
3. Size:
Definition: distance between two edges.
Longer side = length
Shorter side = width
Significance: variation in size will be resulted into out printing and out punching problem. Variation in width at minus side will create grip problem at the feeder of the printing machine and also complete form blanket will not be transfer as sheet is smaller in size variation in length with create feeding problem on machine and also side lay.
4. Bulk: formula – thickness/GSM.
Properties of Paper and Paperboard
The quality and suitability of paper or paperboard depend on its physical and optical properties. These properties determine printing performance, strength, feel, and visual appeal.
Physical Properties
3. Optical Properties
UNIT-3
1. Stiffness:
2. Tensile strength
3. Tearing strength
4. Bursting strength
5. Folding endurance
6. Moisture content
Paper: Aim: check out GSM of paper according to requirement.
1. Stiffness test: it is unit milineuter meter (mnm).
Aim: to check for resist towards bending of paper.
Sampling: draw out flat surface samples form the sheets and cut the required MD & CD sample form that sheet by cutter.
Appratus: stiffness tester, weight box, cutter.
Sample size: length=7cm and width=3.8cm.
Significance: stiffness test is a very important test in board, since the utility of the box depends upon its ability to resists bulging when filled, packages must resists deformation or bulging, when being filled and when the contents settle in a package-folding cartons must also withstand bending stresses from loads imposed on them from containers stacked above.
Leveling: before starting the machine please ensure that all three pointers of pendulum, driving disc and stationery disc and zero. Leveling can be done with the help of leveling screws at the base of the stand.
Cutting of test strip: cut the test strip with the help cut shear, place the material to be cut at the back guage with an additional quick blow with the ball of the hand to detach strip form the sheet. Test smaple will be cut in 1 ½ “X 2 ¾ “size. Immediately mark the grain direction of the board to identify MD & CD.
Formula: Left X 5 + right X 5 / 2.
Ex: 25X5 + 25X5 / 2.
125 + 125 /2 = 250/2
= 125
Operating the instrument: we know strip insert in jaws in marked and down mark according roller only contact not pressure cause pendulum move and the slowly move the roller ¼ turn in reverse direction same procedure R.H.S and put a calibrated range weight on the lower pendulum stud. For 500 unit different range. The mark on the pendulum aligns to the 7 ½ or 15 degree mark on the driving disc. If pointer mark 25 note the reading as 25X5=125 for range weight of 1000 unit the reading will be 25X10=25 taber unit.
Acceptance criteria: stiffness reading should be within 10% of the specified stiffness values.
2. Moisture content:
Definition: the percentage of the part of water in board in normal condition called moisture.
Calculation:-
a. Weight of empty beaker (a) = --------------------- gms.
b. Weight of beaker + substrate (b) = -------------------gms.
c. Weight of substrate (c) = (b-a) = ------------------------ gms.
d. Weight of beaker + substrate (after heater) (d) = ---------------------gms.
e. Weight of moisture loss during heating (e) = (b-d) = ------------------------gms.
% moisture content = E/C X 100.
3. Busting strength:
AIM: check for maximum pressure withstand by the spiceman.
Sample size 10X10cm
Unit: kg/cm2
Apparatus: bursting strength tester.
4. Bursting factor (B.F):
B.S / GSM X 1000
kg/cm2 / gm/cm2 X 1000
5. Picking
Definition: Picking is a printing defect where small portions of paper fibers or coating get lifted and stick to the printing plate, blanket, or roller.
6. Fluffing
Definition: Fluffing occurs when the surface fibers of paper lift up, creating a fuzzy or fibrous surface.
7. Other Related Defects
Corrugation board: resists mechanical impact, increase the time of impulsive forces.
Wood: wood pulp (sulphate process – corrugated board).
Components of corrugated board
a. Liner
b. Fluting
c. Adhesive
The process of running reels of paper into corrugated board is complex process the basic process is to take fluting paper, give it its characteristics wave formation, then stick it to one liner, at a later point in the machine the second liner is applied to fluting, giving to a finished pieces of corrugated board it is than curved cut into the required sizes.
Reel stand of the corrugators hold two reels of paper that are used to product corrugated board. There is at least one reel stand per liner and fluting a corrugated board.
Single facer could be considering the heart of corrugators in this section of the machine the actual wave formation of fluting paper is formed, and bonded to one liner surface among single face paper. Single face that has one liner and one fluting formation. Fluting paper is fed into the single facer from fluting reel stand. The paper passes through a set of corrugated rolls which are like two toothed roller. These rollers form and set the fluting paper into characteristic wave shape. At the same time, from the opposite side of the single facer, the inner of corrugated board is being fed into single facer forming reel stand.
a. Liner: craft paper of above 80 gsm up to 225 gsm is used preferably. The outermost liner used for a box should be of maximum grammage. Their function are.
1. Resist hazard like punter, burst, abrasion tear etc.
2. Properly hold the fluting medium when one combines.
3. Resists moisture or water either outsider or inside depending on the nature of product to the packed.
4. Be amicable for printing.
Water proof paper such as btumen coated, wax coated are also used for liner.
b. Fluting: paper obtained from semi-chemical pulp process are used which proved the good rigidity to the board. Its function are to:-
1. Provide necessary cushioning desired.
2. Provide rigidity to board.
3. Contribute to resistance to bending under stress.
The grammage of fluting medium may be in the region 80-150gsm.
c. Adhesive:
1. Usually starch based adhesive are used for joining the outer liner.
2. Sodium silicate are also used.
Classification: board consisting of one or more shades of fluted paper struck to a flat sheet of paper or board between several liners usually craft, this has following:
a. Single face corrugated
b. 3-ply corrugated
c. 5-ply corrugated
d. 7-ply corrugated
UNIT-4
Plastic: the plastic form a comprehensive family with a wide range of properties which can meet almost every requirement of the packaging industry. Plastic can be trailer made to meet a specific requirement of packaging or achieve a combination of properties. The can be divided into two main group:
a. Thermoplastic: when the contact in heat then it is loss in mechanical or physical properties and not reuse.
b. Thermoset: it soften on the application of sufficient heat, but hardness cooling.
Plastic are used for making rigid containers, flexible container, films and laminations.
Advantage:
a. Plastics are light and less expensive than other packaging material.
b. They have better barrier properties moistures, odor oxygen and other glass.
c. They are resistant to most chemicals, non-toxic in nature.
d. Plastics can be processed into desired shapes of forms like films, sheets, bottles, tubes, pouches and crates.
e. Plastic material saves cost in storage and transportation because of less weight and less secondary packaging.
f. They do not promote bacterial growth.
g. Single-sever cost for food items, such as ketchups and small unit pack like sachets can be made at less cost.
h. Plastic packages are prefer-proof, tamper evident break resistant, corrosion resistant and leak proof.
i. Plastic packaging do not pose any major disposal problem since almost all the plastic can be recycled.
Limitations of plastic packaging:
a. Some chemicals attach particular plastic.
b. Plastic are not total barriers to gases and water vapour, although some new barrier plastic have improved oxygen gas and odor impermeability.
c. Less abrasive resistance and puncture resistance.
1. Polypropylene (PP): polypropylene (PP), also known Poly-propene, is a thermoplastic polymer used in a wide variety of applications including packaging and labelling, textiles (e.g. ropes, thermal under wear and carpets), stationery, plastic parts and reusable containers of various types, polymer banknotes.
Most commercial polypropylene is isotactic and has an intermediate level of crystallinity between that of low density poly-ethylene (LDPE) and (HDPE).
Properties:
a. The monomer units is prop-lene.
b. It is harder and stronger than polyethylene.
c. Very low density (0.9gm/CC).
d. High stiffness and rigidity.
e. High tensile strength.
f. High resistance to chemicals and heat.
g. With sand continuous service temperature of 90 and intermediate temperature of 120C.
Application:
a. Packaging of textiles product.
b. Bakery product.
c. Packaging of shack foods, dry fruit etc.
d. For manufacturing liner of bags, lining material for TV.
e. For making ropes, fibers.
f. High transparency BOPP.
BOPP (bi-axially oriented polypropylene): which polypropylene film is extruded and stretched in both the machine direction and across machine direction. Bi-axially orientation increases strength and clarity.
Features of BOPP films:
a. Excellent clarity.
b. Good dimensional stability and flatness.
c. Low electrostatic charge.
d. Good barrier to water vapour.
e. High gloss.
f. Recyclable.
g. Resistant to oils and greases.
h. Not affected by moistures and does not wrinkles or shrink with environment charges.
It has range from 15 to 50 microns and most commonly 15 to 30 microns.
Applications:
a. Flexible packaging
b. Pressure sensitive tape.
c. Printing and lamination.
d. Stationery
e. Metallizing.
f. Flower sleeves.
g. Cable wrap and insulation.
h. Overwrapping of cigarette, carton (10 to 12 microns).
2. Polystyrene: it is hard, rigid and almost glass like. It is brittle and more easily broken then some other polymer not particular weather resistance so that usually stable for contact use.
a. It is transparent in nature.
b. Light weight.
c. Odorless, non-toxic.
d. Unlimited range of color.
e. Low shrinkage.
f. Little tendency to wrap.
a. For making not drink cups, toys, combs, household articles etc.
b. For making radio and TV bodies.
c. For making tiles.
d. They can be easily decorated by printing Metalishing, hot stamping etc.
3. PVC: polyvinyl chloride (PVC) has a linear structure similar to polyethylene but with a chlorine atom replacing a hydrogen atom on alternate carbon atoms.
It is third most used than polyethylene and polypropylene. It is not recommended for use above 70 celcius although it can be taken to 80 for short periods.
a. PVC is a hard horny material.
b. It is a thermoplastic polymer.
c. Glass like clarity and good mechanical strength.
d. Resistance to gases like oxygen and carbon-dioxide or water and chemicals.
e. Retention of flavor.
f. Lower weight/ volume ratio lower.
a. In the manufacturer of rain coats hand bags, curtain clothes, toys.
b. As a good insulating material in wires and others electrical goods.
c. PVC films the textiles industries as a replacement of cellophane film for packaging of textiles.
4. Polyethylene (PE): polyethylene is a type of polymer that is thermoplastic, meaning that it can melted to a liquid and remolded as it return to a solid state. It is chemically synthesized from ethylene, a compound that is usually made from petroleum or natural gas.
Uses: film, packaging, bags, pipins, industrial applications, containers, food packaging, lamination liners, wire cable. It can be harmful to human and to the environment.
Classification: it is classified into several different categories based mostly on its density and branching. It grade are HDPE, LLDPE, LDPE. It has density value ranging from 0.91 to 0.925 g/cm3, 0.918 to 0.94 g/cm3, 0.935 to 0.96g/cm3.
a. LDPE: it by the high pressure polymerization of ethylene. Its comparatively low density arises from the presence of a small amount of branching in the chain (on about 2% of the carbon atoms).
It is translucent to opaque and it is slowly attacked by strong oxidizing agent and some solvents will cause softening or swelling.
b. High density polyethylene (HDPE): HDPE is prepared from ethylene by a catalytic process. The absence of branching results in a more closely packed structure with a higher density. It higher chemical resistance than LDPE.HDPE is also somewhat harder and opaque. It is strong resistance to moisture, and most chemicals & relatively stable when heated.
Application: it is used to make bottle for milk, juice, water, laundary product, drum and other container. For many kinds of household and industrial chemical. The wrinkly kind of soopy.
c. (LLDPE): it is a sustaintially linear polymer (polyethylene) with significant numbers of short branches, commonly made by copolymerization of ethylene with longer chain olefins.
Features:
a. High strength, durable, weather resistance to high temperature oxidizing, non-toxic.
It is used for plastic bags and sheets, plastic wrap, stretch wrap, pouches, toys, covers, lids, pipes, buckets.
5. Polyethylene terephthalate (PET): it is a thermo-plastic polymer resin of the Polyster family and is used in synthetic fibres, beverage, foods and other liquid containers.
Depending on its processing and thermal history, PET may exist both as a morphous (transparent) and as a semi-crystalline polymer. The semi crystalline material might appear transparent (particles size <500nm) or opaque and white particle size up to a few microns).
It is used for soft drink bottles. Or certain specially bottles, PET sandwiches an additional polyvinyl alcohol layer to further reduce its oxygen permeability. These properties flexible food packaging and thermal insulation such as “space blanket”.
PET to make packaging tray and blisters.
It is produced from ethylene glycol and dimethyl terephthalate (C6H4 (CO2CH3)2) or terephthalic acid.