TA3004. Food Packaging

Lesson 3: Paper and Paper-based Packaging Materials

M.S. Ashanty Miguel Piña Rodriguez ampina@itesm.mx 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