rwanda standard 463 - members.wto.org

ICS 55.100

Reference number

DRS 463:2021

© RSB 2021

RWANDA STANDARD

DRS

463

First edition

2021-mm-dd

Metallic crown caps — Specification

DRS 463: 2021

©RSB 2021 - All rights reserved ii

In order to match with technological development and to keep continuous progress in industries, standards are subject to periodic review. Users shall ascertain that they are in possession of the latest edition

© RSB 2021

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DRS 463: 2021

iii ©RSB 2021 - All rights reserved

Contents Page

Foreword ............................................................................................................................................................ iv

1 Scope ...................................................................................................................................................... 1

2 Normative references ............................................................................................................................ 1

3 Terms and definitions ........................................................................................................................... 1

4 Requirements ......................................................................................................................................... 2 4.1 General requirements ........................................................................................................................... 2 4.1.1 Crown shell ............................................................................................................................................ 2 4.1.2 Liner ........................................................................................................................................................ 2 4.1.3 Crown cap assembling ......................................................................................................................... 2

5 Specific requirements ........................................................................................................................... 3 5.1 Crown shell/base steel .......................................................................................................................... 3 5.2 Liner ........................................................................................................................................................ 3 5.3 Moisture content .................................................................................................................................... 3

6 Dimensions of the crown caps ............................................................................................................ 4 6.1 Crown cork dimension .......................................................................................................................... 4 6.2 Pry off crown profiles............................................................................................................................ 5 6.3 Twist off or Universal crown profiles .................................................................................................. 6

7 Packaging and storage ......................................................................................................................... 6

8 Marking ................................................................................................................................................... 6

9 Sampling ................................................................................................................................................ 7

Annex A (normative) Determination of overall migration of constituents of plastics materials and articles intended to come in contact with foodstuffs - Method of analysis .................................... 8

A.1 Types of simulants ................................................................................................................................ 8 A.2 Selection of standard test conditions and simulants for different foodstuffs ................................ 8 A.3 Selection of Sample ............................................................................................................................ 10 A.4 Procedure ............................................................................................................................................. 10 A.5 Determination of Amount of Extractive ............................................................................................. 10

DRS 463: 2021

©RSB 2021 - All rights reserved iv

Foreword

Rwanda Standards are prepared by Technical Committees and approved by Rwanda Standards Board (RSB) Board of Directors in accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT agreement on the preparation, adoption and application of standards.

The main task of technical committees is to prepare national standards. Final Draft Rwanda Standards adopted by Technical committees are ratified by members of RSB Board of Directors for publication and gazettment as Rwanda Standards.

DRS 463 was prepared by Technical Committee RSB/TC 020, Packaging and packaging materials.

In the preparation of this standard, reference was made to the following standards:

1) IS 1994: 1987 Crown closures

2) US 2240:2020 Metallic crown caps — Specification

The assistance derived from the above source is hereby acknowledged with thanks.

Committee membership

The following organizations were represented on the Technical Committee on Packaging and packaging materials. (RSB/TC 020) in the preparation of this standard.

Ministry of Trade and Industry (MINICOM)

Rwanda Inspectorate, Competition and Consumer Protection Authority (RICA)

National Agricultural Export Development Board (NAEB)

University of Rwanda-College of Science and Technology (UR-CST)

BRALIRWA Plc.

Skol Brewery Ltd

NITRIVO food and beverages Ltd

Rwanda Standards Board (RSB) – Secretariat

DRS 463: 2021

v ©RSB 2021 - All rights reserved

Introduction

Metal crown caps are well known because of their strict association with glass bottles. In fact, crown corks are designed to secure seal in capping applications with glass and aluminium bottles in the brewing and beverage market for soft-drinks and alcoholic beverages.

Efficient packaging is of great importance for the distribution and the protection of goods to ensure food safety. Insufficient or inappropriate packaging can lead to damage or wastage of the contents of the pack.

DRS 463: 2021

1 ©RSB 2021 - All rights reserved

Metallic crown caps — Specification

1 Scope

This Draft Rwanda Standard specifies the requirements, sampling and test methods for metallic crown caps, also known as crown corks or crow seal, designed to secure seal in capping applications with glass and aluminium bottles.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 11950, Cold-reduced tinmill products — Electrolytic chromium/chromium oxide-coated steel

ISO 11949, Cold-reduced tinmill products — Electrolytic tinplate

RS EAS 354, Plastic containers for up to 5 litres capacity — Specification

ISO 15512, Plastics — Determination of water content

RS ISO 2859-1, Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection

3 Terms and definitions

For the purposes of this standard, the terms and definitions given in ISO 11950 and ISO 11949 and the following apply.

3.1

metallic crown cap

light gauge metal lined with cork or plastic used to close off the opening of narrow neck bottles and prevent loss of its contents

3.2

crown shell

metallic component of the crown cap

©RSB 2021 - All rights reserved 2

3.3

liner

medium used to form a seal between a closure and a container

4 Requirements

4.1 General requirements

4.1.1 Crown shell

The crown shell also known as base steel shall be:

a) made from Tin Free Steel (TFS) also known as Electrolytic chromium/chromium oxide-coated steel (ECCS) or Electrolytic Tinplate; and

b) have either a stone finish or matt finish, bright finish or silver finish.

4.1.2 Liner

The liner shall:

a) be manufactured from food grade Thermoplastic Elastomers (TPE) , PVC, PVC free with proper sealing ability;

b) be manufactured in compliance with Good Manufacturing Practice;

c) contain inhibitor approved for use in food products;

d) be free from pits and pinholes;

e) have no adverse effect on the food product (e.g. through chemical reactions, leaching of liner materials or absorption);

f) neither be affected by the foodstuff packed nor altered by the ingredients of the food in its final form in terms of its properties and protective function;

g) not result into unacceptable changes in the organoleptic characteristics of the foodstuff; and

h) not be manufactured using post-consumer recycled materials.

4.1.3 Crown cap assembling

4.1.3.1 Lined crown cap shall be fitted with the liner and shall be well-matched with the bottle they are intended to seal. When tested in accordance with RS EAS 354, the lined crown cap shall not leak, nor allow diffusion and permeation.

DRS 463: 2021


4.1.3.2 The liner shall firmly adhere to the shell so that it cannot fall or displayed from the crown shell during storage, transportation or when the bottle is sealed.

4.1.3.3 The adhesive used to bind the liner to the crown shell shall be of non-toxic quality

5 Specific requirements

5.1 Crown shell/base steel

The crown shell shall be made from ECCS complying with ISO 11950 or Electrolytic Tinplate complying with ISO 11949 when tested in accordance with the test methods specified therein.

In addition to the requirements of ISO 11949 and ISO 11950, the steel base type L that is food grade shall comply with the chemical composition requirements given in Table 1. Incomprehensible

Table—1 Chemical composition of the base steel for metallic crown caps

S/No. Element Cast composition, %, max.

Carbon 0.13

Manganese 0.60

Phosphorus 0.020

Sulfur 0.03

Silicona,b 0.020

Copper 0.06

Nickel 0.04

Chromium 0.06

Molybdenum 0.05

AluminiumC 0.10

Other elements, each 0.02

a When steel produced by the silicon killed method is ordered, the silicon maximum may be increased to 0.080 %.

b When strand cast steel produced by the aluminium killed method is ordered or furnished, the silicon maximum may be increased to

0.030 % when approved by the purchaser.

c Types L may be supplied as non-killed or killed, which would respectively be produced without and with aluminium additions.

5.2 Liner

When tested in accordance with Annex A the overall migration limit of the liner constituents shall not exceed 60 milligrams per kilogram of the simulant, equivalent to 10 milligrams of total non-volatile substances released into food simulant per square decimetre of surface area of the liner.

5.3 Moisture content

For satisfactory assembly and to avoid excessive sweating in the lined crown caps, the initial moisture content in the composite cork shall be 4-6% when tested in accordance with ISO 15512.


6 Dimensions of the crown caps

Dimensions of crown caps shall be as given in Figures 1, 2, 3 and 4

6.1 Crown cork dimension

Figure 1 — Dimensions of crown cork

DRS 463: 2021


6.2 Pry off crown profiles

Figure 2 — Dimensions of pry off crown caps (Profile 916)

Figure 3 — Dimensions of pry off crown caps (Profile 923)


6.3 Twist off or Universal crown profiles

Figure 4 — Dimensions of twist off / Universal crown profiles (profile 917)

7 Packaging and storage

7.1 Crown caps shall be packaged in one of the following:

a) strong carton boxes with biodegradable liner for protection;

b) one way strong bulk octabins; or

c) one way heat treated and fumigative pallets.

7.3 All packaging materials shall be recyclable.

7.4 Crown caps shall be packaged, stored and transported in a clean and dry environment, away from direct sunlight and at temperatures not exceeding more than 40 °C.

8 Marking

The bulk package of the crown caps shall be marked with the following information:

a) name and /or trade mark of the manufacturer and physical address;

b) sealing force for twist off crowns;

DRS 463: 2021


c) opening torque for twist off crowns;

d) shelf life;

e) batch number;

f) storage instructions; and

g) Number of pieces in a box and number of boxes per bulk package.

9 Sampling

Sampling shall be done in accordance with RS ISO 2859-1.


Annex A (normative)

Determination of overall migration of constituents of plastics materials and articles intended to come in contact with foodstuffs - Method of

analysis

A.1 Types of simulants

The determination of migration in simulants is to be carried out using the simulants laid down:

a) Simulant ‘A’ - distilled water or water of equivalent quality.

b) Simulant ‘B’ - 3 percent acetic acid (w/v) in aqueous solution (using the simulant ‘A’)

c) Simulant ‘C1 - 10 percent ‘ethanol (v/v) in aqueous solution for foodstuffs aqueous solution for foodstuffs having alcohol less than 10 percent (v/r)) (using the simulant ‘A’).

d) Simulant ‘C2’ - - 50 percent ethanol (v/v) in aqueous solution for foodstuffs having alcohol more than 10 percent and less than 50 percent (r/v) (using the simulant ‘A’).

e) Simulant ‘D’ -n-heptane - shall be freshly distilled before use.

f) Simulant ‘E’-Rectified olive oil or mixture of synthetic triglycerides or sunflower oil.

NOTE This simulant ‘E’ suggested by EEC for fatty foods need not be considered at present as the methodology of

estimation is not yet developed.

A.2 Selection of standard test conditions and simulants for different foodstuffs

4.1 The choice of simulating solvents and test conditions (time-temperature) depends on the type of foodtuff and its condition of use. Food products have been classified into seven major groups suitable simulants to be used for different types of foods as per Table 1.

Table A1—Classification of Foods and Selection of simulant

S/N Type

of

food

Description Examples Simulant

i. I Aqueous, non-acidic foods

without fat (pH > 5)

Honey, mineral water, sugar syrups molasses, skimmed milk, rusgulla, infusions, murabba, yeast,

paste etc yeast paste etc

‘A’

ii. II Aqueous. acidic foods without

fat (pH ≤ 5 5 )

Fruit juices, squashes, fruit chunks or puree or

paste, vinegar, jams, jellies, carbonated beverages. lemonade, processed vegetables, rennet,

preparations of soups, broths, sauces, RTS

beverages etc

‘B’

DRS 463: 2021


iii. III Alcoholic

beverages:

i)Alcohol concentration

less than 10

percent

Beer and some pharmaceuticals syrups ‘C1”

ii)Alcohol concentration

above 10 percent

Wine, brandy, whiskey, arrack and other alcoholic

drinks

‘C2’

iv. IV Oils. fats and processed dry foods with surface fat or

volatile oil

Vegetable oils, ghee, cocoa butter, lard,

biscuits, spice powder, snacks and savoury.

chocolate,

caramels, malted foods, egg powder, tea, coffee

powder

confectionery, fried and roasted nuts etc

‘D’

v. V Nonacidic foods (pH > 5) or high fat and having high

moisture content

Butter, bread, pastry shreekand with low cakes, milk based sweets, ice-cream, moist and fatty

confectionery products

A and D’

vi. VI Acidic foods (pH ˂ 5) or high

fat and having high moisture

content

Pickles, ketchup, cheese, with low curd, fresh and

processed meat and fish products, sauces having

fat, frozen foods, mayonnaise etc

‘B and D’

vii. VII Dry processed foods without

fat

Cereals and pulses, dehydrated vegetable and

fruits, dried yeast. corn flakes, salt, sugar, milled products, barley powder, oats, vermicelli, spaghetti

etc

No end test

4.2 Table 2 lists the simulants and test conditions (time-temperature) for extractability studies to be carried out as above depending on the type of food and conditions of use.

Table 2—Simulating solvents for different types of food, temperature and time conditions

S/No. Conditions of use Type of

food

Water (time-

temperature )

3 % Acetic

acid

(time-

temperature)

10% alcohol

(time-

temperature)

50% alcohol

(time-

temperature )

n-Heptane

i. High temperature heat sterilized

(Retorting)

I, II, IV, V

and VI

121°C, 2h 121°C, 2h - - 66°C for 2 h

ii. Hot filled or pasteurized above

66°C, 100°C

I, II, IV, V

and VI

100°C, 2h 100°C, 2h - - 49°C for 30

minutes

iii. Hot filled or

pasteurized below

66°C

I to VI 700C, 2h 700C, 2h 700C, 2h 700C, 2h 38°C for 30

minutes

iv. Room temperature filled and stored (no

thermal treatment in container) and also in

refrigerated and

frozen condition

do 400C, 10 days 400C, 10

days

400C, 10

days

400C, 10 days do

NOTES


1 Heptane simulant not to be used on wax lined containers.

2 Heptane extractivity results must be divided by a factor of five in arriving at the extractivity of a food product

A.3 Selection of Sample

At least triplicate samples each consisting of a number of closures/sealing gaskets/liners with the lids exposing about 100 cm2 contact area (or ten lids) per replicate in each representing a lot or batch shall be selected.

A.4 Procedure

Smallest size glass bottles/jars actually being intended for use with closures can be used as containers to contain the simulant. Fill the glass container to their nominal capacity or 100 ml, whichever is lower with simulant preheated to test temperature and closed tight with the closures/lids lined with the test specimen.

Place the closed containers upside down (to ensure the contact of the closures with the simulant) in an oven maintained at test temperature. After the exposure to the stipulated time, the closure from the containers are opened and the contents from each replicate is pooled together in a glass beaker along with the washings of the exposed closures with small amount of fresh simulant. Blank shall also be carried out without the sample.

A.5 Determination of Amount of Extractive

Evaporate/distill the contents in Pyrex beaker to about 50-60 ml and transfer into a clean tared stainless steel dish along with 3 washings of Pyrex beaker with small quantity of fresh simulant and further evaporate the concentrate in the dish to dryness in an oven at 100 + 5°C. Cool the dish with extractive in a desiccator for 30 minutes and weigh to nearest 0.1 mg till constant weight of residue is obtained. Calculate the extractives in mg/dm* and mg/kg or mg/l or ppm of the foodstuff with respect to the capacity of container/pouch to be used. Blank shall also be carried out without the sample.

Calculate the amount of extractive in ppm for the particular size of container being tested.

Amount of extractive (Ex) = 𝑀

𝑉x1000 mg/kg or mg/l

Or Ex= 𝑀

𝐴x100 mg/dm2

Where

M = mass of residue in mg minus blank value,

A= surface area in cm2 exposed in each replicate

and

V = volume of the container in ml in a replicate in actual use.

DRS 463: 2021


Bibliography

[1] ASTM A 623 – 16 Standard Specification for Tin Mill Products, General Requirements

[2] US 1659:2016 Materials in Contact with Food — Requirements for Packaging materials

[3] IS 9845 (1998): Determination of overall migration of constituents of plastics materials and articles intended to come in contact with foodstuffs – method of analysis

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