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TA3004. Food Packaging
Lesson 3: Paper and Paper-based Packaging Materials
M.S. Ashanty Miguel Piña Rodriguez [email protected] Campus Queretaro Spring 2012
Module 2: Food Packaging Materials
Objectives
• To learn about the different types of paper
• To learn about the different uses of paper products
• To learn basic processes of manufacturing paper
• To discriminate among commonly used paper packaging materials for food products
Food Packaging Materials • 4 major materials:
Metal
Cans
Films
Glass
Bottles
Jars
Paper / Cardboard
Boxes/cases
Bags
Tubes/cups
Plastic
Flexible •Bags •Films / liners
Rigid •Containers •Cases/cups •Bottles
Biobased materials
Attributes of paper and paper-based packaging
• Recyclable • Mechanical resistance • Flexible • Printable • Available raw materials • Inexpensive
(Source: USDA Agricultural Research Service)
Raw Materials ▫ Paper, paperboard, corrugated board, and other paper-
based materials
• Pulp - cellulose • Additives • Pigments • Polymeric liners
• ~97% of paper and board is made from wood pulp ▫ 85% wood pulp: spruces, firs and pines (coniferous)
Pulping
• Separate the fibers without damaging them
• Softening or removal of Lignin ▫ Chemical Process ▫ Mechanical Process ▫ Semi-Chemical Process ▫ Chemi-Mechanical
• Increases cellulose content (Source: USDA Agricultural Research Service)
Mechanical Pulps • Groundwood ▫ High cost (energy usage) ▫ Preserves most of the
lignin Smaller and weaker fibers Higher in opacity Low mechanical strength
▫ Mainly used for newsprint and magazine paper
• Refiner mechanical pulping (RMP) ▫ Utilizes various supplies of wood chips, sawmill
residues, and sawdust
• Thermomechanical pulping (TMP) ▫ Pre-steams chips to 110-150°C
• Chemi-thermomechanical pulping (CTMP) ▫ Mild pretreatment with sodium sulfite and a
pressurized refining
Chemical Pulps
• Degrades and dissolves away the lignin
• Alkaline Processes ▫ Soda process: sodium hydroxide at 170°C ▫ Sulfate (Kraft) process: Sodium sulfate
• Acid Process ▫ Sulfite processes: Bisulfite + sulfurous acid ▫ Recent modification involves anthraquinone and
methanol
Paper packaging
• 3 major groups:
▫ Packaging papers ▫ Cartons ▫ Corrugated box
Paper Types
• Coarse papers – i.e. packaging ▫ In general, good grease and
water resistant Not so good as gas barriers
▫ Resist oil penetration for as long as a food product’s life
Paper Types (coarse) • Greaseproof paper • Vegetable parchment
• Glassine paper • Waxed paper
• Adhesives ▫ Starch solutions ▫ Rubber latex ▫ Acrylic-based (for paperboard) Odor free
• Barriers ▫ To water vapor and environment gases (oxygen, volatiles,
etc) Paraffin (vs water vapor) Polyethylene Cellulose derivatives, rubber derivatives, vinyl copolymers,
polyamides, polyester, and butadiene-styrene copolymers. • Pigments ▫ ~70-90% of dry solids in paper coatings
Cartons
• From paperboard ▫ Paper >224 g/m2
• Multi-ply boards – one or more web plies into a single sheet of paperboard ▫ Boxes ▫ Folding cartons ▫ Beverage cartons ▫ Other products
Folding Cartons
• Paper material ▫ Foodboard ▫ Cartonboard
Beverage Cartons
• Paper material ▫ foodboard
How cartons are made?
http://www.youtube.com/watch?v=jNbKIc8tD5I 7:24 min
Molded Pulp Containers
• Paper material ▫ Chipboard ▫ Base board
http://www.youtube.com/watch?v=hA1BU77tDTs&feature=related
Corrugated board
• Cellular structure ▫ High compressive strength / relative low weight
• Two components ▫ Liner – outside planar sheet ▫ Medium – fluted center portion
• Different fiberboards from various combinations
• Single face ▫ 1 liner, 1 flute
• Single Wall Board ▫ 2 liners, 1 flutes ▫ B, C
• Double Wall Board ▫ 3 liners, 2 flutes ▫ BC
• Triple Wall Board ▫ 5 liners, 3 flutes ▫ BCB, BCC
Flutes
(Source: Smurfit, www.packaging-gateway.com)
• 4 flute sizes ▫ Height flute ▫ Number flutes/unit length
• “A” – maximum cushioning and good top-to-bottom compression
• “B” – smooth printing surface • “C” – compromise between A/B, the
most common • “E” – for retail boxes, with good
printing quality
Double Wall Board: B+C
• Flute B ▫ Height 2.46mm ▫ 47 flutes/30cm linear ▫ Oriented to the outside Good printing quality
• Flauta C ▫ Height 36mm ▫ 39 flutes/30cm linear ▫ Oriented to the inside Good compression resistance
Corrugated Boxes
• Functions ▫ Contain a product ▫ Protect the product during distribution ▫ Resistance to stacking ▫ Communicate content characteristics ▫ Reduce weight and cost
• http://www.youtube.com/watch?v=NsPnGAtufok
Factors involved in the selection of corrugated boxes
• Identify the contained product • Identify the distribution and
transport systems • Identify the geographic areas of
distribution • Elaborate prototypes ▫ Testing: travel, compression,
stacking • Elaborate final specifications of
corrugated box
Designing a corrugated box
• $ COST $ • Material to construct a box (m2)
• Dimensions L×W×H
• % wasted material • More material – more expensive
Cost reduction
• Material saving ▫ i.e. 3 boxes with same cubic contents, different waste
factor (P) ▫ 70-80% total cost = raw material
• Space saving ▫ Different stacking arrangements, shape arrangement ▫ i.e. 24 cartons (11×4×15cm), different arrangements using
0.494-0.675 m2 board, latter P=36%
• Metrication ▫ Favors packs of 10’s
• Economy ▫ Favors packs of 6, 12,
24, etc.
Monograph for calculating wastage (%P) of board for regular slotted containers
Corrugated boxes styles
Interior fitments
• Pads ▫ Fill spaces ▫ Cover the bottom ▫ Separate layers
• Tubes ▫ Double protection
• Partitions ▫ Separate cell
• Stacking Resistance ▫ Corrugated board caliper ▫ Box dimensions ▫ Volum density ▫ Stacking levels ▫ External factors Humidity Nominal forces Mishandling
Effect on stacking strength • lower in a much
economical box proportion
• Most economical relations:
Box Style Length Width Height
0201 2 1 2
0204 1 1 2
0301 1 1 0,25
0320 2 1 1
Compression Resistance • Several situations may cause a loss on the compression
resistance
• When there’s no uniformity in the vertical stacking
-29%
• Boxes hanging over the edge of the pallet. The two vertical edges of the box not hanging over the pallet edge are primarily supporting the load
-32%
• Use of interlocking stacking patterns
-45%
• Printing Method ▫ Printing rollers (i.e. flexography, lithography) and the type
of ink could reduce compression resistance up to 15%
Mediciones de Resistencia
• ECT (Edge Crush Test) ▫ Measures the maximum compression
strength of a combined board. ▫ Used to calculate the stacking resistance ▫ Lbs/in
• BCT (Box Compression Test) ▫ It is the maximum load a given box can stand for a moment. 60-90% occurring at 5cm from the edges
McKee Formula • A formula that can estimate the compression strength of a
given box ▫ Total caliper H (cm)
▫ Box Perimeter Z (cm)= (L+ W) x 2
▫ ECT Pm (Kg/cm2)
• http://www.cartoncorrugado.com.mx/herramientas.html • http://www.harperlove.com/files/documents/newsnovember10.p
df
Product-Packaging Interaction Paper and paper-based materials
Product
• Permeability
• Migration
Packaging
• Sorption
Environment
Consequence
• Packaging
deterioration
• Product degradation
• Possible toxic effect; Packaging corruption
Environmental Repercussions
• Paper is recyclable
• Recycled paper can be used to make ▫ More paper ▫ Furniture ▫ Construction materials
• KEYS ▫ Sustainability ▫ Responsibility
How many trees???
• 1 ton printing and office paper uses 24 trees (Kraft method)
• 1 ton newsprint uses 12 trees (Groundwood method – twice tree efficient)
• 1 tree makes 16.67 reams of copy paper or 8,333.3 sheets
• 1 ton of magazine paper uses a little more than 15 trees
• 1 ton of newsmagazine paper uses nearly 8 trees
• 1 ton (40 cartons) of 30% postconsumer content copier paper saves 7.2 trees
• 1 ton of 50% postconsumer content copier paper saves 12 trees.
• 1 ton of recycling paper ▫ Saves 17 trees ▫ 380 gal oil won’t be used ▫ 4000 KW of power are saved
• http://www.youtube.com/watch?v=rZl7KAESsaA