Yam, Kit L. (ed.). The Wiley encyclopedia of packaging technology

Подождите немного. Документ загружается.

both address materials, standards, and associated test

methods, but do not speciﬁcally address their use in

packaging. The scope of TC 34, ‘‘Agricultural Food Pro-

ducts,’’ and TC 126, ‘‘Tobacco and Tobacco Pro-

ducts,’’ includes packaging, storage, and transport of

such products but is, in practice, limited to general,

practical advice. When necessary, TCs may create liai-

sons with other appropriate TCs concerned with

packaging.

Because international standardization is a lengthy

and expensive process, proposals for new standards

must be justiﬁed by identifying the need, the aim(s) of

the proposed standard, and the interests that may be

affected. Once a document is developed, it is listed under

the relevant Technical Committee in the annual ISO

Technical Programme (4) as draft proposals or draft

international standards (DISs) in increasing degrees of

formality. When a technical committee agrees on a draft

standard, it is proposed for approval by all ISO members.

If 75% of the votes cast are in favor of the DIS, it is sent

for acceptance to the ISO Council. This provides an

assurance that no important objections have been

overlooked.

There is no requirement for ISO member bodies to

publish an ISO standard as a national standard, although

it is through such action that ISO standards are put into

use throughout the world. On occasion, publication of an

ISO standard as a national standard is not considered

appropriate.

All ISO standards are listed in the ISO Catalogue (5)

and on the ISO Online web site (at http://www.

iso.ch/welcome.html). ISO standards can frequently

be purchased from national standards bodies (ISO

member bodies) or directly from ISO on-line at: http://

www.iso.org/iso/en/prods-services/ISOstore/store.html.

ISO PACKAGING STANDARDS

Six technical committees have developed ISO standards

directly concerned with packaging.

TC 51: Pallets for Unit Load Method of Materials

Handling. Tasked with standardizing pallets for

general use in the form of platforms or trays on

which goods may be packed to form unit loads, TC 51

has currently developed nine standards listed in

Table 2.

TC 52: Light-Gauge Metal Containers. Through the

work of TC 52, the number of different sizes of open-

top, general-purpose food cans has been reduced

from over 2000 in 1947 to a total of 35 by the time

Table 1. Continued

TC 220: Cryogenic Vessels

Scope: Standardization in the ﬁeld of insulated vessels (vacuum or non-vacuum) for the storage and the

transport of refrigerated liqueﬁed gases of class 2 of ‘‘Recommendations on the Transport of

Dangerous Goods—Model Regulations—of the United Nations,’’ in particular concerning the

design of the vessels and their safety accessories, gas/materials compatibility, insulation

performance, the operational requirements of the equipment and accessories

Secretariat: Association franc- aise de normalisation (AFNOR)

11, rue Francis de Pressense

FR-93571 Saint-Denis La Plaine Cedex

Tel: +33 1 41 62 80 00

Fax: +33 1 49 17 90 00

E-mail: uari@afnor.org

Web: http://www.afnor.org

Secretariat direct:

Tel: +33 1 41 62 84 50

E-mail: nicole.legent@afnor.org

Table 2. ISO Standards for General-Purpose Pallets (TC 51)

ISO 445 Pallets for Materials Handling—Vocabulary

ISO 6780 General-Purpose Flat Pallets for Through Transit of Goods—Principal Dimensions and Tolerances

ISO 8611 General-Purpose Flat Pallets for Through Transit of Goods—Test Methods

ISO/TR 10232 General-Purpose Flat Pallets for Through Transit of Goods—Design Rating and Maximum Working Load

ISO/TR 10233 General-Purpose Flat Pallets for Through Transit of Goods—Performance Requirements

ISO/TR 10234 General-Purpose Flat Pallets for Through Transit of Goods—Phytosanitary (plant health) Requirement for Wooden

Pallets

ISO/TR 11444 Quality of Sawn Wood Used for the Construction of Pallets

ISO/TR 12776 Pallets—Slip Sheets

ISO 12777-1 Methods of Test for Pallet Joints—Part 1: Determination of Bending Resistance of Pallet Nails, Other Dowel-Type

Fasteners and Staples

618 INTERNATIONAL STANDARDS

ISO 3004-1:1986 was issued. This still may be too

many, but it represents the best possible compro-

mise at the present time. The range of standards for

light-gauge metal containers, following the current

program of work, is listed in Table 3.

TC 63: Glass Containers. Concerned with standardiz-

ing glass containers used as a means of packaging

(excluding containers made from tubular glass), TC

63 developed 15 standards, listed in Table 4. With no

further work item under study or foreseen, TC 63

has since been dissolved.

TC 104: Freight Containers. The standards relating to

freight containers (Table 5) are perhaps the best

possible example of international standardization,

because without them, the ‘‘container revolution’’

could never have taken place. Standardized dimen-

sions, maximum gross masses, and, above all, stan-

dardized methods of lifting (twist locks and corner

ﬁttings) have enabled rapid, safe transfer of the

containers from one transport mode to another.

These type standards relate not only to box containers

but also to tank containers for liquids, gases, and

solids.

TC 122: Packaging. The committee with the broadest

scope, TC 122, works to standardize packaging

terminology and deﬁnitions, as well as packaging

dimensions, performance requirements, and tests,

but excludes matters falling within the scopes of

other committees (e.g., TC 51, TC 52, TC 63, and TC

104). These standards are listed in Table 6.

Table 3. ISO Standards for Light-Gauge Metal Containers (TC 52)

ISO 90-1 Light-Gauge Metal Containers—Deﬁnitions and Determination Methods for Dimensions and Capacities—Part 1:

Open-Top Cans

ISO 90-2 Light-Gauge Metal Containers—Deﬁnitions and Determination Methods for Dimensions and Capacities—Part 2:

General-Use Containers

ISO 1361 Light-Gauge Metal Containers—Open-Top Cans—Round Cans—Internal Diameters

ISO 3004-1 Light-Gauge Metal Containers—Capacities and Related Cross Sections—Part 1: Open-Top Cans for General Food

ISO 3004-2 Light-Gauge Metal Containers—Capacities and Related Cross Sections—Part 2: Open-Top Cans for Meat and

Products Containing Meat for Human Consumption

ISO 3004-3 Light-Gauge Metal Containers—Capacities and Related Cross Sections—Part 3: Open-Top Cans for Drinks

ISO 3004-4 Light-Gauge Metal Containers—Capacities and Related Cross Sections—Part 4: Open-Top Cans for Edible Oil

ISO 3004-5 Light-Gauge Metal Containers—Capacities and Related Cross Sections—Part 5: Open-Top Cans for Fish and Other

Fishery Products

ISO 3004-6 Light-Gauge Metal Containers—Capacities and Related Cross Sections—Part 6: Open-Top Cans for Milk

ISO/TR 8610 Light-Gauge Metal Containers—Round Vent-Hole Cans with Soldered Ends for Milk and Milk Products—Capacities

and Related Diameters

ISO/TR 10193 Round General-Use Light-Gauge Metal Containers—Nominal Filling Volumes and Nominal Diameters

ISO/TR 10194 Nonround General-Use Light-Gauge Metal Containers—Nominal Filling Volumes and Nominal Cross Sections

ISO 10653 Light-Gauge Metal Containers—Round Open-Top Cans—Cans Deﬁned by Their Nominal Gross Lidded Capacities

ISO 10654 Light-Gauge Metal Containers—Round Open-Top Cans—Cans for Liquid Products with Added Gas, Deﬁned by Their

Nominal Filling Volumes

ISO/TR 11761 Light-Gauge Metal Containers—Round Open-Top Cans—Classiﬁcation of Can Sizes by Construction Type

ISO/TR 11762 Light-Gauge Metal Containers—Round Open-Top Cans for Liquid Products with Added Gas—Classiﬁcation of Can

Sizes by Construction Type

ISO/TR 11776 Light-Gauge Metal Containers—Nonround Open-Top Cans—Cans Deﬁned by Their Nominal Capacities

ISO 11944 Round General-Use Light-Gauge Metal Containers—Nominal Diameters for Cylindrical and Tapered Cans up to

10,000-mL Capacity

Table 4. ISO Standards for Glass Containers (TC 63)

ISO 7348 Glass Containers—Manufacture—Vocabulary

ISO 7458 Glass Containers—Internal Pressure Resistance—Test Methods

ISO 7459 Glass Containers—Thermal Shock Resistance and Thermal Shock Endurance—Test Methods

ISO 8106 Glass Containers—Determination of Capacity by Gravimetric Methods—Test Method

ISO 8113 Glass Containers—Resistance to Vertical Load—Test Method

ISO 8162 Glass Containers—Tall Crown Finishes—Dimensions

ISO 8163 Glass Containers—Shallow Crown Finishes—Dimensions

ISO 8164 Glass Containers—520-mL Euro-form Bottles—Dimensions

ISO 9008 Glass Containers—Verticality—Test Method

ISO 9009 Glass Containers—Height and Nonparallelism of Finish with Reference to Container Base—Test Methods

ISO 9056 Glass Containers—Series of Pilferproof Finish—Dimensions

ISO 9057 Glass Containers—28-mm Tamper-Evident Finish for Pressurized Liquids—Dimensions

ISO 9058 Glass Containers—Tolerances

ISO 9100 Wide-Mouth Glass Containers—Vacuum Lug Finishes—Dimensions

ISO 9885 Wide-Mouth Glass Containers—Deviation from Flatness of Top Sealing Surface—Test Methods

INTERNATIONAL STANDARDS 619

TC 220: Cryogenic Vessels. Standardization in the

ﬁeld of insulated vessels (vacuum or non-vacuum)

for the storage and the transport of refrigerated

liqueﬁed gases of class 2 of ‘‘Recommendations on

the Transport of Dangerous Goods—Model Regula-

tions—of the United Nations,’’ in particular concern-

ing the design of the vessels and their safety

accessories, gas/materials compatibility, insulation

performance, and the operational requirements

of the equipment and accessories. By the end of

2006, TC 220 had developed 13 standards (listed in

Table 7).

ISO 9000: QUALITY SYSTEMS STANDARDS

In 1979, the ISO formed Technical Committee ISO/TC 176

on Quality Management and Quality Assurance to de-

velop a single, generic quality system standard that could

be used for external quality-assurance purposes. In 1987,

Table 5. ISO Standards for Freight Containers (TC 104)

ISO 668 Series 1 Freight Containers—Classiﬁcation, Dimensions, and Ratings

ISO 830 Freight Containers—Terminology

ISO 1161 Series 1 Freight Containers—Corner Fittings—Speciﬁcation

ISO 1496-1 Series 1 Freight Containers—Speciﬁcation and Testing—Part 1: General Cargo Containers for General Purposes

ISO 1496-2 Series 1 Freight Containers—Speciﬁcation and Testing—Part 2: Thermal Containers

ISO 1496-3 Series 1 Freight Containers—Speciﬁcation and Testing—Part 3: Tank Containers for Liquids, Gases, and Pressurized

Dry Bulk

ISO 1496-4 Series 1 Freight Containers—Speciﬁcation and Testing—Part 4: Nonpressurized Containers for Dry Milk

ISO 1496-5 Series 1 Freight Containers—Speciﬁcation and Testing—Part 5: Platform and Platform-Based Containers

ISO 3874 Series 1 Freight Containers—Handling and Securing

ISO 6346 Freight Containers—Coding, Identiﬁcation, and Marking

ISO 8323 Freight Containers—Air/Surface (intermodal) General-Purpose Containers—Speciﬁcation and Tests

ISO 9669 Series 1 Freight Containers—Interface Connections for Tank Containers

ISO 9711-1 Freight Containers—Information Related to Containers on Board Vessels—Part 1: Bay Plan System

ISO 9711-2 Freight Containers—Information Related to Containers on Board Vessels—Part 2: Telex Data Transmission

ISO 9897-1 Freight Containers—Container Equipment Data Exchange (CEDEX)—Part 1: General Communication Codes

ISO 9897-3 Freight Containers—Container Equipment Data Exchange (CEDEX)—Part 3: Message Types for Electronic Data

Interchange

ISO 10368 Freight-Thermal Containers—Remote Condition Monitoring

ISO 10374 Freight Containers—Automatic Identiﬁcation

Table 6. ISO Standards for Packaging in General (TC 122)

ISO 780 Packaging—Pictorial Marking for Handling of Goods

ISO 2206 Packaging—Complete, Filled Transport Packages—Identiﬁcation of Parts When Testing

ISO 2233 Packaging—Complete, Filled Transport Packages—Conditioning for Testing

ISO 2234 Packaging—Complete, Filled Transport Packages—Stacking Tests Using Static Load

ISO 2244 Packaging—Complete, Filled Transport Packages—Horizontal Impact Tests (horizontal or inclined plane test;

pendulum test)

ISO 2247 Packaging—Complete, Filled Transport Packages—Vibration Test at Fixed Low Frequency

ISO 2248 Packaging—Complete, Filled Transport Packages—Vertical Impact Test by Dropping

ISO 2873 Packaging—Complete, Filled Transport Packages—Low-Pressure Test

ISO 2875 Packaging—Complete, Filled Transport Packages—Water-Spray Test

ISO 2876 Packaging—Complete, Filled Transport Packages—Rolling Test

ISO 3394 Dimensions of Rigid Rectangular Packages—Transport Packages

ISO 3676 Packaging—Unit-Load Sizes—Dimensions

ISO 4178 Complete. Filled Transport Packages—Distribution Trials–Information to Be Recorded

ISO 4180-1 Complete. Filled Transport Packages—General Rules for the Compilation of Performance Test Schedules—Part 1:

General Principles

ISO 4180-2 Complete. Filled Transport Packages—General Rules for the Compilation of Performance Test Schedules—Part 2:

Quantitative Data

ISO/TR 8281-1 Packaging—Estimating the Filled Volume Using the Flat Dimensions—Part 1: Paper Sacks

ISO 8317 Child-Resistant Packaging—Requirements and Testing Procedures for Reclosable Packages

ISO 8318 Packaging—Complete, Filled Transport Packages—Vibration Tests Using a Sinusoidal Variable Frequency

ISO 8474 Packaging—Complete, Filled Transport Packages—Water Immersion Test

ISO 8768 Packaging—Complete, Filled Transport Packages—Toppling Test

ISO 10531 Packaging—Complete, Filled Transport Packages—Stability Testing of Unit Loads

ISO 11683 Packaging—Tactile Danger Warnings—Requirements

ISO 12048 Packaging—Complete, Filled Transport Packages—Compression and Stacking Tests Using a Compression Tester

620 INTERNATIONAL STANDARDS

on the basis of the work of TC 176, the ISO published the

ISO 9001 Standard. No other standard developed by the

ISO has had as much impact on a global scale as this ISO

9001.

ISO 9001 was developed by researching a number of

national standards from several ISO member countries

including Great Britain’s BS 5750 and BS 4891, France’s

AFNOR Z 50-110, Germany’s DIN 55-355, the Nether-

land’s NEN 2646, Canada’s Z-299, and the United States’

ANSI/ASQC Z-1.15, MIL-Q-9858A, ANSI/ASQC C-1, and

ANSI/ASME NQA-1 (6).

Each representative member country participating in

the ISO has taken ISO 9001 back to their respective

country and, after translation, issued it a designation

unique to that country. In the United States, ISO 9001 is

published by the American National Standards Institute

(ANSI), in conjunction with the American Society for

Quality (ASQ), and is referenced as ANSI/ISO/ASQ Q9001.

ISO 9001 is a generic, baseline quality standard writ-

ten with the intent of being broadly applicable to a wide

range of varying nonspeciﬁc industries and products. With

this objective, ISO 9001 establishes the basic require-

ments necessary to document and maintain a marginal

quality system. These quality system requirements are

intended to be complementary to speciﬁc product require-

ments. This broad objective is ISO 9001’s strength.

For example, the current version of ISO 9001 (2000

edition) contains broad requirements relating to packa-

ging (in section ‘‘7.5.5 Preservation of Product’’), stating:

The organization shall preserve the conformity of product

during internal processing and delivery to the intended desti-

nation. This preservation shall include identiﬁcation, hand-

ling, packaging, storage and protection. Preservation shall also

apply to the constituent parts of a product.

Therefore, as appropriate to the product, any of the ISO

packaging standards listed in this article may be utilized

within an ISO 9001 compliant quality management

system.

INTERNATIONAL CODES, RECOMMENDATIONS,

REGULATIONS, AND TECHNICAL INSTRUCTIONS

Several other international organizations have developed

codes, recommendations, regulations and technical in-

structions that should also be mentioned here:

1. UN Recommendations on the Transport of Danger-

ous Goods, Model Regulations. Prepared by the

United Nations ‘‘Committee of Experts on the Trans-

port of Dangerous Goods and on the Globally Har-

monized System of Classiﬁcation and Labelling of

Chemicals.’’ These recommendations may be viewed

(14th edition, 2005) or ordered online at

http : ==www:unece:org=trans=danger=publi=

unrec=rev14=14files_e:html

2. The International Maritime Dangerous Goods Code

(IMDG). Published by the International Maritime

Organization. For more information on the IMDG,

including how to order the latest edition, visit:

http : ==www:imo:org=Safety=mainframe:asp?

topic

d ¼ 158

3. The Dangerous Goods Regulations (DGR). Available

from International Air Transportation Association

(IATA)

800 Place Victoria

PO Box 113

Montreal H4Z 1M1

Quebec, Canada

Phone: +1 514 874 0202

Fax: +1 514 874 9632

Web Site: http://www.iata.org/

4. Annex 18 to the Convention on International Civil

Aviation—The Safe Transport of Dangerous Goods

Table 7. ISO Standards for Cryogenic Vessels (TC 220)

ISO 20421-1 Cryogenic Vessels—Large Transportable Vacuum-Insulated Vessels—Part 1: Design, Fabrication, Inspection and

Testing

ISO 20421-2 Cryogenic Vessels—Large Transportable Vacuum-Insulated Vessels—Part 2: Operational Requirements

ISO 21009-2 Cryogenic Vessels—Static Vacuum Insulated Vessels—Part 2: Operational Requirements

ISO 21010 Cryogenic Vessels—Gas/Materials Compatibility

ISO 21012 Cryogenic Vessels—Hoses

ISO 21013-3 Cryogenic Vessels—Pressure-Relief Accessories for Cryogenic Service—Part 3: Sizing and Capacity Determination

ISO 21014 Cryogenic Vessels—Cryogenic Insulation Performance

ISO 21028-1 Cryogenic Vessels—Toughness Requirements for Materials at Cryogenic Temperature—Part 1: Temperatures below

80 degrees C

ISO 21028-2 Cryogenic Vessels—Toughness Requirements for Materials at Cryogenic Temperature—Part 2: Temperatures Between

80 degrees C and 20 degrees C

ISO 21029-1 Cryogenic Vessels—Transportable Vacuum Insulated Vessels of not more than 1000 Litres Volume—Part 1: Design,

Fabrication, Inspection and Tests

ISO 21029-2 Cryogenic Vessels—Transportable Vacuum Insulated Vessels of not more than 1000 Litres Volume—Part 2:

Operational Requirements

ISO 23208 Cryogenic Vessels—Cleanliness for Cryogenic Service

ISO 24490 Cryogenic Vessels—Pumps for Cryogenic Service

INTERNATIONAL STANDARDS 621

by Air. This may be purchased from ICAO at the

following address:

International Civil Aviation Organization

Attention: Document Sales Unit

999 University Street

Montreal, H3C 5H7

Quebec, Canada

E-mail: Sales@icao.int

Web Site: http://www.icao.int/

BIBLIOGRAPHY

1. What Are Standards, IBSA (International Business Standards

Association) web site, http://www.ibsa.ws/.

2. ISO web site, http://www.iso.org/iso/en/aboutiso/introduction/

index.html.

3. ISO Mememto, International Organization for Standardiza-

tion, Geneva, Switzerland, annual publication.

4. ISO Technical Programme, International Organization for

Standardization, Geneva, Switzerland, annual publication.

5. ISO Catalogue, International Organization of Standardiza-

tion, Geneva, Switzerland, annual publication.

6. R. Randall, Randall’s Practical Guide to ISO 9000, Addison-

Wesley, Reading, MA, 1995, p. 7.

IONOMERS

BARRY A. MORRIS*

DuPont Packaging and

Industrial Polymers,

Wilmington, Delaware

Ionomers are premier heat seal polymers that have found

use in demanding packaging applications requiring ex-

cellent seal reliability, formability, and toughness. The

term ionomers was coined by the DuPont Company in

the early l960 s to describe polymers having both ionic and

covalent linkages (1, 2). In particular, ionomers was used

to describe the polymers originally sold under the regis-

tered trademark of SURLYN

. These polymers are made

by high-pressure free-radical polymerization of ethylene

with an unsaturated organic carboxylic acid and then

partially neutralized with a metal ion (3). The acid groups

in these polymers are incorporated randomly along the

polymer backbone. While DuPont ionomers are typically

made from ethylene–methacrylic acid copolymers, the

Dow Chemical Company, and A. Schulman ionomers are

made from ethylene–acrylic acid copolymers (4) All

four companies supply grades neutralized with either

zinc or sodium ions. The ionomers above are composed

of ethylene-unsaturated carboxylic acid–carboxylate salt.

In addition, DuPont offers some grades that contain a

termonomer, isobutyl acrylate. Isobutyl acrylate acts to

reduce the polymer’s modulus and melting point. It also

increases toughness and improves adhesion to certain

substrates. Mitsui–DuPont in Japan offers ionomers simi-

lar to SURLYN

ionomer resins under the registered

trademark of HI-MILAN

Recently, DuPont introduced a potassium-based iono-

mer resin under the tradename ENTIRAt AS, which is a

permanent antistat. It can be blended with polyoleﬁns

such as polyethylene or polypropylene to reduce static

buildup. Other polymeric materials are also included in

the classiﬁcation of ionomers (5, 6), but the discussion

here will be limited to those based on ethylene copolymers

that are used as sealants in packaging applications.

Structure, physical properties, processing, and selected

end uses are covered below.

IONOMER STRUCTURE

The polymer that can be considered the ‘‘parent’’ of these

ionomers is low-density polyethylene (LDPE). The struc-

ture of LDPE consists of crystalline and amorphous

phases, but ionomers contain a third ionic phase composed

of metal ions and neutralized carboxylate groups. The

structural units of this third phase are called ionic clusters

and are illustrated in Figure 1. They possess an internal

order, the exact nature of which depends on the type of ion

present. These clusters are responsible for the unique set

of properties of ionomers.

For instance, ethylene-unsaturated acid copolymers

exhibit improved toughness compared to LDPE because

of hydrogen bonding between carboxylic acid groups on

different polymer chains. Ionomers made by neutralizing

some of the acid groups in such polymers have not only

hydrogen-bonding forces holding polymer chains together

but also the much stronger ionic forces from clusters that

interconnect polymer chains, as shown in Figure 2. The

attractive forces, called ionic crosslinks, weaken with

increasing temperature, making the polymer more readily

processable than an LDPE polymer having comparable

melt ﬂow index.

Although the order within the clusters decreases with

increasing temperature, the clusters themselves are not

destroyed even at temperatures as high as 5721F (3001C).

When heated polymer is allowed to cool, reordering of the

structure within the clusters and crystallization of short

polyethylene segments causes a substantial increase in

the modulus of the polymer. The modulus of the cooled

polymer and its rate of attaining ultimate modulus de-

pends on the processing temperature, the storage tem-

perature, and relative humidity.

PHYSICAL PROPERTIES

The amount of acid incorporated into the backbones of

ionomer chains may range from 7wt% to 30 wt% for

commercial products. These acid groups are usually neu-

tralized from about 15% to 80%. Even a relatively low

amount of neutralized acid provides signiﬁcant changes in

* This article was updated by Barry A. Morris. The original article

was written by George Hoh, DuPont packaging and Industrial

polymers, Wilmington, Delaware.

622 IONOMERS

physical properties compared to LDPE. Increasing acid

content and percentage neutralization causes the follow-

ing properties to increase: tensile strength, modulus,

toughness, clarity, abrasion resistance, puncture resis-

tance, resistance to both mineral and vegetable oils and

fats, moisture absorption, and melt strength. Properties

that decrease are melting point, haze, surface tack, and

notched tear resistance.

Adhesion to polar materials such as aluminum foil,

nylon, and paper in coextrusion or extrusion coating is a

direct function of the amount of unneutralized acid in the

ionomer. Adhesion to nonpolar polyethylene is decreased

by increasing amounts of acid and carboxylate salt. Zinc

ionomers tend to have a broader range of adhesion than do

sodium ionomers and are less hygroscopic. Sodium iono-

mers offer superior grease resistance and optical

properties.

PROCESSING

Unlike LDPE, ionomers are hygroscopic. Manufacturers

supply them in a dry state, and they need to be kept dry

for proper processing. Ionomers can be processed in typical

extrusion and coextrusion equipment that is suitable for

extruding LDPE, with the exception that corrosion-resis-

tant equipment needs to be used. For blown-ﬁlm extrusion,

ionomer grades having melt-ﬂow indices ranging from

fractional to about 5 dg/min are suitable, although grades

having melt ﬂows as high as 14 dg/min can be extruded

because ionomers possess exceptional melt strength. The

melt strength of ionomers is sometimes used to help carry

other layers in coextrusion. For extrusion coating, grades

having melt-ﬂow indices ranging upward from about 2.5 dg/

min are suitable. Because ionomers have afﬁnity for metal

surfaces, grades for extrusion coating beneﬁt from the use

of matte chill rolls. Use of a chill-roll release additive also

can be helpful, especially if a gloss chill roll is required.

Cast-ﬁlm processing is also suitable for ionomers.

Unlike LDPE, the extrusion temperature should not

exceed 5901F (3101C). Good practice calls for maintaining

a slow ﬂow of ionomer through the equipment during

nonproduction periods. Ionomers need to be purged with a

polyoleﬁn resin from the extruder and die prior to an

extended shutdown.

APPLICATIONS

Vertical Form/Fill/Seal Packaging

Many of the uses of ionomers in packaging depend on the

melt-strength, melt-ﬂow, and adhesion characteristics of

this polymer family. As a heat-seal layer especially for

vertical form (VFFS) packaging, a property that is extre-

mely important is called ‘‘hot tack,’’ which is the capability

of a newly formed (still molten) heat-seal bond to resist an

opening force. In the case of VFFS packaging, the force is

exerted on the end seal by product being dumped into the

package. If the hot tack of the seal layer is insufﬁcient, the

seal may open partially or completely. Ionomers excel in

melt strength, and seal widths of packages can be mini-

mized by their use as the seal layer (see also Form/ﬁll/seal,

vertical).

Ionic clusters

Crystalline

region

Amorphous region

Figure 1. Morphology of ethylene ionomers. Iono-

mers contain crystalline and amorphous regions

similar to LDPE, but also contain ‘‘ionic clusters’’

that impart a unique balance of properties.

−

Figure 2. Chemical structure of ethylene ionomers. The inter-

action between the metal salt (M) and the carboxylic groups on

the polymer chain creates ‘‘ionic crosslinks.’’

IONOMERS 623

A comparison of the hot tack proﬁles of a low-perfor-

mance zinc ionomer, an acid copolymer, and LDPE is

shown in Figure 3. For a given hot-tack strength, say,

750 g/in., the operating-temperature window of the iono-

mer is greater than 751F, that of the acid copolymer is

401F, and the LDPE polymer has insufﬁcient hot-tack

strength to meet the requirement. The width of the hot-

tack window for ionomers contributes to seal reliability

and reduced dependence on highly accurate temperature

control of the sealing operation.

Ionomers also have low seal initiation temperatures

because the crystalline melting point of the parent LDPE

has been reduced by copolymerization of acid and/or

ester. Since their seal strength is maintained at the

high-temperature end of the sealing range, this means

that the overall heat-seal operating window is widened

and contributes to increased packaging line speeds and

seal reliability. The melt-ﬂow characteristics of ionomers

also allow them to ﬂow and seal around particulate

contaminants that may be in the seal area, also increas-

ing seal reliability. Abrasion resistance of ionomers is a

beneﬁt in packaging food products that tend to be

abrasive.

Ionomers have greater stiffness than other sealants

with similar low-temperature sealability, such as EVA’s

and polyethylene plastomers. The stiffness of a ﬁlm

affects its ability to be handled in high-speed packaging

lines and impacts the package appearance and feel. Be-

cause the sealant is one of the outer layers in a multilayer

structure, it can have a large impact on the stiffness of the

ﬁlm (7). Sealant stiffness also affects the slow puncture

resistance of a packaging ﬁlm; stiffer ionomer resins

impart better puncture resistance than softer plastomers.

This is important for many dry food and meat (bone)

applications.

Visual Carded Display Packaging

This type of packaging, also called ‘‘skin packaging,’’ is

used both for retail hanging card displays and for indus-

trial packaging to hold products to a board for shipping.

The toughness, optical clarity, and minimal board-curling

properties of ionomers make them particularly suited for

this use.

Thermoformed Packages

The melt strength of ionomers allows deeper draw depths

of packaging webs utilizing an ionomer layer compared to

use of other polymers. Coextrusions of ionomers with

nylon have been useful in packaging processed meats

and cheese. Methacrylic acid-based ionomers also have

the property of providing adhesion to the protein of meats

and reduce the amount of purge, that is, liquid exudation

formed during meat processing. Because of their melt-ﬂow

properties, ionomers also have superior properties com-

pared to other polymers for sealing through contamina-

tion, as from meat juices. This property gives webs having

ionomer seal layers a reduced amount of package leakage,

reducing waste and cost.

A specialized type of thermoformed packaging is called

‘‘Stretch Pak,’’ in which a ﬁlm attached to a windowed card

is thermoformed, and the product is placed in the cavity.

The packaged object is held snugly in the custom-shaped

cavity when passing the package through a heated shrink

tunnel shrinks the ﬁlm.

Aluminum-Foil-Based Packaging

Ionomers containing unneutralized acid groups have

found wide utility as the seal layer in extrusion-

coated aluminum foil structures. The acid groups provide

adhesion to the foil, while the superior sealing and

chemical-resistance characteristics of the ionomer permit

packaging a wide variety of products.

BIBLIOGRAPHY

1. R. W. Rees, Modern Plastics, 42, 209 (1964).

2. R. W. Rees and D. J. Vaughan, Polymer Preprints, Vol. 6,

American Chemical Society Division of Polymer Chemistry,

1965, p. 287.

3. U.S. Patent 3,264,272, R. W. Rees.

4. G. L. Baker and L. It. Compton, ‘‘Introduction of Acrylate

Copolymer Based Ionomer Resins for Packaging Applications,’’

1995 TAPPI Polymers, Laminations & Coatings Conference,

Preprints, 1995, p. 625.

5. R. W. Rees, ‘‘Ionomers’’ in J. Kroschwitz, ed., Kirk Encyclopedia

of Chemical Technology, 4th edition, Vol. 14, John Wiley &

Sons, New York, 1995.

6. R. Longworth, ‘‘Ion Containing Polymers: Their Structure and

Application,’’ Plast. Rubber, 3, 75 (1978).

7. B. A. Morris and J. Vansant, ‘‘The Inﬂuence of Sealant Mod-

ulus on the Bending Stiffness of Multilayer Films,’’ SPE

ANTEC, 1, 35–40 (1998).

500

1000

1500

2000

175 200 225 250 275 300 325

Interface Temperature, °F

Hot-tack strength, g/in

Ionomer, 5 MFI

Acid Copolymer, 10 MFI

LDPE, 6 MFI

Figure 3. Hot-tack strength comparison, DuPont spring test.

624 IONOMERS

JAPANESE PACKAGING

ANDREW W. STREETER

CPS International Pack-Track

Cambridge, United Kingdom

INTRODUCTION

No country in the world is as collectively dynamic with

consumer packaging than as Japan. It is a country as

much in love with (or certainly with a positive liking for),

as well as fully appreciating of, its commercial potential.

The phenomenon is not new; we have traced it back some

few hundred years, but it has certainly for the past 50

years been a key packaging leader in the world.

Japan is also is a very wealthy country, with one of

the highest per-capital values (US$37050 GDP per capita;

second only to the United States) of the ‘‘big’’ countries in

the world. This huge spending power and a discerning

market is a breeding ground for packaging innovation and

change, and Japan rises and fulﬁls this challenge well.

This article explores the different facets of Japanese

packaging, where culture is as important as commerce

and the science of change. Change is in fact frequent

in Japan, with packaging not always technically new

but certainly visually new and collectively pushing back

boundaries of packaging possibilities. It is a fascinating,

seductive, and energetic packaging world that is globally

trend setting.

THE UNIQUE JAPANESE PACKAGING CULTURE

We have traced the application of packaging back 200

years or more to when bakeries used to wrap their cakes

and confectionery in different ways to distinguish them

from rival producers. Over time, this became more inter-

esting and entertaining for the consumer, with more

elaborate folding of the wrapping and with clever uses

of materials. Materials then were primarily paper, and

there is a (much longer) parallel here with origami in the

creative use of paper materials.

Out of this value-adding use of paper wraps for cakes

evolved three principles that have held good in Japan to

this day, which you can observe in even the most advanced

pack. First, there is the stated need for differentiation

while retaining market sector recognition.

Second, it is a statement of care and a statement of

pride on behalf the baker. He or she is saying through the

packaging, ‘‘Here is my product and I thank you for buying

it; I present it to you with care, that you may both enjoy it

and enjoy the anticipation of it as you unwrap and use the

product.’’

In that last point lies the third quality; over time, it has

evolved that to unwrap a pack should be pleasurable,

enhancing expectation, and an integral part of the product

experience. The pack is part of the product, true now in

the developed regions of the world, but Japan was ﬁrst in

this respect, and in Japan it remains more true and more

extensive than anywhere else.

We have evolved a phrase from Robert Louise Steven-

son that reﬂects this quality: ‘‘to travel is as important as

to arrive.’’ When you see, hold, open, use, and ﬁnally throw

away a pack in Japan, you are on a journey that should be

positive and enhance the experience of the product or

brand.

The consequences of these factors are that consumer

packs are designed in every aspect to a high degree of

functionality, which is ﬁnessed for consumer handling and

commercial considerations of cost. Packs in Japan are well

built; easy to open, dispense, and recluse; and today will

have a sustainability dimension about them. All that is

undertaken in a way that engages the consumer with the

brand.

It is not just the history of packaging application that is

a driver, however; the Japanese people have high and

typically unshakeable standards. It is about quality, qual-

ity, and quality; consumer packaging is a beacon of that

way of life.

THE IMPORTANCE OF GOOD PACKAGING DESIGN

The role of packaging design is key in securing these

multifunctional needs out of the one pack. But design is

visualized, and the sector structure is different in Japan

when compared with other regions of the world. Every

department in the product manufacturing company will

work hard to make the pack work at a proﬁtable margin.

There is a cultural acceptance to agree on a proposed

pack and then deliver it, whereas in the west, by way of

example, we argue and debate.

To an outsider, a visit to a Japanese supermarket would

reveal a cornucopia of fascinating packaged brands and

products, but that romantic pleasure should not disguise a

ruthless commercial approach to a product or brand, by

this integral association, or its packaging success. If it

does not deliver the expected ROS (rate of sale per linear

meter on shelf) straight away, it is delisted, and this can be

as little as 4 days after launch. So, packaging has to work

hard immediately.

A key driver in this need is in the pack design. It can be

segmented into graphics, new structures, and new con-

cepts, and each has to add something more to the past

packaging design.

Packaged brands are often created for a short market

life, sometimes just a few months. A brand can be the

same product but in new or evolved graphic interpreta-

tions. Change is part of the brand ethic, so there is a

constant desire for a new package and something to smile

about, which creates an exciting and/or an inventive

graphic design community.

625

A key strategy in this, ironically, is the Japanese

language. Its character script has over 10,000 characters,

and it is not until about the age of 10 that a young person

would have mastered the language sufﬁciently. Conse-

quently, symbols are frequently used in packaged brand

communication and have reached a high level of evolution.

Pack designers are extensive users of symbols and other

devices. It is often easy for non-Japanese to understand

what is inside a Japanese packaged brand because sym-

bolism has a universal quality.

More than graphics, however, Japan has international

fame for its new pack structures and concepts where multi

disciplined packaging design skills are required. The

expression ‘‘holistic design’’ is very appropriate in Japan.

Allied to this is a business ethic of introducing new

packaging ideas to the market; packaging ideas that can

be groundbreaking like the bottle made from paper pulp

(image 2). And like the paper pulp bottle, it is accepted

that there is a degree of failure, although this failure could

be more often one of timing—often ahead of the market-

than anything else and certainly not technical failure.

Even during the protracted recession of the 1990s, Japan’s

packaging industry continued to create and manufacture

innovative new packaging.

Japan is often recognized as being an ‘‘overpackaged’’

society, but this not really the case. First, you cannot

compare on a like for like basis, as the standard in Japan

is so much higher, in terms of quality expectations, than

elsewhere. A simple printed can in Japan is more expen-

sive because its cheaper western counterpart is not made

to the same standard. The other aspect to the overpacka-

ging perception is also a value one—the need to protect

and to ensure that each product is virgin and clean.

Couple this with creating pleasure when using the pack

and ‘‘unwrapping’’ and the expectation of being functional,

and the difference is one of standards, Japan (brings) to

the west. Do these higher standards come at an inap-

propriate premium? We think not and have the opinion

that Japan, on a pack comparative basis, pays 1 1/2% to

5% more in packaging unit cost. The value that is deliv-

ered is certainly more than the cost, for the Japanese

consumer, but maybe in the west we are not there yet.

From that standpoint, Pack concept design in Japan

can often deliver a sought-after feature: value adding

while not cost adding, and in some instances, cost reduc-

tion as well. By way of an example, the small S&B Raa-yu

bottle (image 3) has a (a) one-piece closure that is (b)

simple to manufacture, (c) provides controlled drops of oil,

(d) in an intuitive way to use, (e) engaging to use, (f) low in

unit cost, and (g) functions perfectly. Controlling the

dispensing of small qualities of oily substances in the

kitchen is tricky and has created many complex, costly

and at times inadequate packaging devices, yet the closure

on the S&B Raa-yu bottle is simple and effective. It is a

good example of value up and cost down.

THE PACKAGING INDUSTRY AND PACK DESIGN

The value and culture of new pack design is not lost on the

packaging manufacturing industry, where nearly all types

of packaging design are controlled by the packaging

industry. There are very few independent packaging

designers or consultants in Japan. Every medium-sized

and upward packaging company would have its own in-

house designers, and outside design houses would typi-

cally be allied to packaging companies.

The packaging industry, like nearly all industry in

Japan, is rather incestuous. Everything is kept within

one giant network of suppliers, which is linked by

tradition and trusted by time. Added to this, vertical

integration is common; for example, the food company

Anjinomoto owns a packaging company, a distribution

company, and a retailing arm. Control, a fast decision,

and ﬂow of goods enhance the whole ethic of quickly

introducing new packaging designs and concepts.

With basic issues like graphic design change, a sub-

stantial amount of work is created for everyone within the

supply chain; turnover grows, employment prospects are

made sound, and there is constant market excitement.

The mechanisms involved may be open to criticism, but it

does work and it does produce some of the most interesting

packaging in the world.

The packaging industry leverages design to match the

fast changing market needs, and brands often have a

projected life of just a few months, so in graphic terms

there are constant print changes as designs come out. By

tradition, there are beer brands for the different seasons,

each one rotating by graphic design every few months, and

each season sees a new design.

THE PACKAGING MANUFACTURING INDUSTRY

Japan has a large packaging manufacturing industry that

represents a steady 1.3% of GPD (515,733 billion Yen in

2007). The industry has 18 major players, which include

foreign subsidiaries like Nihon Tetra Pack. Some of these

companies are international, like Mitsubishi, Toppan

Printing Company, and Dia Nippon Printing, and in

companies where packaging is part of a wide and, in the

case of Mitsubishi, diverse range of materials, goods, and

services.

In monetary terms, there has been tiny but steady

growth in materials leaving the factory gates; glass is in

decline and metal is ﬂat, as is to be expected, but this is

offset by plastics growth and small improvement in the

total value of paperboard.

In tonnage terms, the movement upward has been

modest indeed, reﬂecting a mature society, and all sectors

are more or less ﬂat.

Japanisanimportantandactiveproducerofpackaging

machinery. The sales value and machine numbers in the

table below reﬂect, like materials, modest overall growth,

except

that machines to

do with ﬂexible packaging have seen

asteadygrowthinlinewithmarkettrendsinthissector.

As costs increase, the industry has been outsourcing

and investing within the wider region. Toppan established

a base in China in the 1980s, when the situation there

was different than today. Packaging machinery compo-

nents are manufactured in China and ﬁnished, and the

machine was assembled in Japan. Principle countries in

626 JAPANESE PACKAGING

Company Packaging sectors

Sales 2007 USD

(millions) Mid-2000’s thinking

Mitsubishi Plastics Plastics 12,259 From rigid to ﬂexible

Kureha Corporation Plastics 828 Enhancing high barrier

Chuo Kagaku Plastics 623 Bioplastics and eco-friendly

Toyo Seikan Kaisha Metal cans, PET, Plastics 5372 Continuing pack sustainability

Hokkai Holdings Steel cans, PET 16 Can innovation, sustainability

Daiwa Can Metal, plastics 1538

Global expansion

Fujimori Kogyo Flexibles 571 Functional ﬁlms

Cow Pack Co Ltd Pouch & closer 38 Pouch innovation

Dia Nippon Print Plastics, board 16,275 Pack and print innovation

Nihon Yamamura Glass, PET 562 New glass products, hot PET

Ishizuka Glass Glass 498 Light weighting, value adding

Nihon Tetra Pak Liquid cartons 572

Recycling, Carbon reduction

Toppan Printing Board, plastics 13,166 Pack/ﬁlm innovation

Tokan Kogyo Cups, containers 454 Part of Toyo Seikan

Oji Paper Paperboard 10,323 Forest & paper recycling

Nippon Paper Paperboard 12,798 Global growth & resource

recycling

Rengo Company Corrugated board 3637 Pack improvement, recycling

2008. PET, polyethylene terephthalate.

Overview of shipment value of packaging materials and containers

2005 - ﬁnal - 2006 (including estimate) 2007 (including estimate)

Grand total 59,712 (100.0) 60,496 (100.0) 62,315 (100.0)

102.9% 101.3% 103.0%

Paper and Paperboard Products 24,744 (41.4) 24,794 (41.0) 25,168 (40.4)

101.1 100.2 101.5

Plastic Products 16,922 (28.3) 17,713 (29.3) 18,920 (30.4)

109.8 104.7 106.8

Metal Products 10,721 (18.0) 10,482 (17.3) 10,626 (17.1)

98.1 97.8 101.4

Glass Products 1463 (2.4) 1396 (2.3) 1377 (2.2)

97.0 95.5 98.7

Wooden Products 1629 (2.7) 1660 (2.7) 1638 (2.6)

98.5 101.9 98.7

Miscellaneous (including seals,

labels, tapes, textile products,

and cellophanes)

4234 (7.1) 4451 (7.4) 4586 (7.4)

104.5 105.1 103.0

Upper column: Shipment value in 100 million yen(\), Figures in parentheses shows composed ratio (%).

Lower column: Comparison with previous year (%).

Overview of shipment volume of packaging materials and containers

2005 - ﬁnal - 2006 (including estimate) 2007 (including estimate)

Grand Total 20,911 (100.0) 20,843 (100.0) 20,837 (100.0)

99.3% 99.7% 100.0%

Paper and Paperboard Products 12,649 (60.5) 12,695 (61.3) 12,715 (61.0)

100.0 100.4 100.2

Plastic Products 4005 (19.2) 3998 (19.2) 4023 (19.3)

100.0 99.8 100.6

Metal Products 1996 (9.5) 1951 (9.4) 1939 (9.3)

97.9 96.4 99.4

Glass Products 1525 (7.3) 1466 (7.0) 1427 (6.8)

96.3 96.2 97.3

Wooden Products 736 (3.5) 734 (3.5) 734 (3.5)

102.5 100.0 100.0

Upper column: Shipment volume in 1000 tons, Figures in parentheses shows composed ratio (%).

Lower column: Comparison with previous year (%).

JAPANESE PACKAGING 627