Testing of Rigid Packaging Materials

 Glass Containers

The Important Parameters of Testing are :

(a) Visual Defects

Significance: This is required to check the quality of glass container physically.

Test Method: The critical and major defects to be examined are :

i) Critical Defects : Cracked or broken glass, choked bore, internal fins, flanged finish, over press, split finish, channeled and wrapped sealing surface, shifted finish and rocker bottom.

ii) Major Defects : Stones, seeds, cords, blisters, oil marks, bad distribution,deformation etc.

(b) Inspection of Colour

Significance: To cross check the colour of the bottle as per requirement.

Test Method: The selected colour glass bottle is examined by comparing with an approved sample in terms of colour shade.

(c) Dimensions

Significance: The dimensions of glass container is highly critical as the dimensions of containers directly affect the automatic filling operation, labelling operation,capping, sealing and thus cause hindrance to marketing.

Test Method: The measurement of dimensions are done by means of ‘Go’,‘No-Go’ gauge. A number of dimensions are examined for glass containers.

(d) Overall Height

For checking any one type of bottle a ‘Go’ ‘No-Go’ gauge may also be adequate.

i) Leading Horizontal Dimensions

A ‘Go’ and ‘No-Go’ gauge are generally satisfactory for checking body dimensions.

ii) Verticality:

The verticality of bottles can be measured as deviations, with a suitable set up consisting of a vertical shaft, a ‘V’ block and dial gauge. The details of this test are prescribed in IS: 2091 – 1983

iii) Ovality

The ovality is determined by measuring the maximum and the minimum leading horizontal dimension along the circumferences using a vertical caliper.

iv) Finish Dimensions

The term ‘Finish’ refer to that part of the glass container which takes on the closure. The dimensions are examined with the help of ‘Go’ and ‘No-Go’ gauge.

e) Capacity Measurement

Significance: The capacity of the bottle is defined either as the brimful capacity or capacity upto a filling height agreed upon.

Test Method: The glass bottle is filled with water and then the actual quantity is measure by measuring cylinder and thus, the capacity of bottle is expressed as cubic centimeter or C.C. (Ref : IS: 10497 : Method of test for the determination of brimful capacity of glass container by gravimetric method)

(f) Mechanical Impact Strength

Significance: This test is useful to the extent of defecting gross manufacturing defects in respect to mechanical strength of glass bottle.

Test Method: The normal test is to use a pendulum consisting of a hardened steel ball as a striker. This method is called as pendulum method to determine the mechanical impact strength.

(g) Annealing

Significance: To determine the interface of colour of glass containers which might happen during gradual cooling process.

Test Method: The specimen sample is subjected to a polariscope and then viewed the glass containers through the polarised light to determine any sign of stained glass due to interface of colour.

(h) Thermal Shock Test

Significance: The main objective of this test is to determine the resistance of thermal shock of glass containers.

Test Method: The test specimen of glass containers are subjected to sudden temperature difference by means of filling hot water followed by cold water. And then, the observations are taken for any breakage or crackness on the glass containers.

(i) Hydrostatic Pressure Test

Significance: To determine the resistance of glass containers against withstanding

of pressurized liquid.

Test Method: This particular test is performed by means of a hydrostatic pressure test equipment. The details are described in IS :10516 : Methods of test for internal pressure resistance for glass containers).

(j) Impact Testing

Significance: To determine the rigidity or impact strength of glass containers.

Test Method: This test will signify about the impact strength or resistance against breakage due to sudden load on the containers.

(k) Pendulum Test

Significance : To check the vertical impact strength of glass containers.

Test Method : This particular test is conducted in a testing equipment where the glass container is placed in vertical position and then a steel ball is allowed to swing and strike the bottle. Subsequently, the glass containers are checked for any kind of breakage or crackness due to impact.

(l) Chemical Test

Significance : To identify the composition of glass materials.

Test Method : The glass container are broken into pieces and then glass pieces are analysed in the laboratory by means of sedimentation process to identify the composition of glass materials.

Metal Containers

The important parameters for the testing of metal containers are as follows :

Visual Inspection

Significance : To inspect visually about the printing aspect and other manufacturing defects to assess the quality of packaging materials.

Test Method : The test specimens are selected by following the standard sampling method and then samples are inspected visually for different important parameters like manufacturing defects, printing defects, any spots cuts, proper joints etc. of the containers.

(a) Dimensions

Significance : To check the dimensions of the metal containers in order to comply with the standard sample (Ref IS : 1060 – PART 1, 1985 )

(i) Container Height : The height of containers is very important as affects the automatic filling line. The dimensions are measured either by using seale or digital gauge.

(ii) Overseam Diameter : The dimensions are checked by means of particular dial gauge and expressed in millimeter.

(iii) Capacity

Significance : To determine the actual capacity of container so that there should be any hindrance in the automatic filling operations.

Test Method : The particular metal container is taken and filled with water upto the brimful capacity. The containers is then emptied where water is measured in the measuring cylinder and thus, the capacity of metal containers is calculated.

(b) Tin Coating Thickness

Significance : To check the thickness of tin coating (internal) as well as (external) of the tin plate.

Test Method :

The tin coating is measured either by using chemical solvant (CLEARK’S solution) or by elcometer.

(c) Hydraulic Pressure Test

Significance : To check the extent of withstanding capacity of the metal container when exposed to hydraulic pressure.

Test Method : The filled metal containers are subjected to hydraulic pressure test equipment and then held for 5 minutes to observe any leakage of the containers.

(d) Air Pressure Test

Significance : To determine the leakage of metal container.

Test Methods : The empty metal containers are filled with air and then dipped in water tank to observe any appearance of air bubble and to identify the leakage.

(e) Product Compatibility

Significance : To check the compatibility of the product with the internal contact surface of metal containers.

Test Method : The metal container is filled with skimmed milk powder and exposed to accelerated conditions i.e. 38ºC +-1º C & 90% +- 2% R.H. for minimum period of 90 days. The exposed samples are also withdrawn at an interval of 7 days and the products are analysed for all the parameters.

Plastic Containers

Significances and Test of Important Parameters :

The details of important tests are discussed below :

(a) Identification of Plastics

Significance : To determine the type of polymeric material used for the manufacturing of blow moulded plastic containers.

Test Method : The samples are subjected to burning test to get smell, appearance of smoke etc to identify the polymer. Subsequently, the density of polymeric materials could be identified.

(b) Wall Thickness

Significance : This is important to check the uniformity of thickness of containers.

Test Method : The thickness is measured by slide caliper or any other dial gauge micrometer and it is expressed as millimeter or micron.

(c) Dimensions

Significance : To check the dimensions of plastic containers.

Test Method : All the dimensions like neck diameter, body diameter, height,thread dimensions, etc are determined by means of dial gauge micrometers.

(d) Capacity

Significance : To check the brimful capacity of containers.

Test Method : The plastic container could be filled with water and the capacity of water is measured by gravimetric method.

(e) Environmental Stress Crack Resistance

Significance : To determine the resistance to crack of plastic container against environment.

Test Method : The test is conducted in the laboratory by following the method prescribed in IS : 8747 ( Environmental stress crack resistance of blow moulded plastic container ).

(f) Extrability Test

Significance : To check wheather the polymeric materials are of food grade or not.

Test Method : This test is conducted in the laboratory by following the test methods as prescribed in IS : 9845 (Extractability studies on plastics).

Corrugated Fibre Board Boxes

Significances and Test of Important Parameters :

i) Kraft Liner, Fluting Media

The following tests are performed on liner and fluting medium.

(a)Grammage

Significance : Grammage is a measure of the weight of paper or paper board expressed in gms per square meter. It is also called as substance. Its unit is gms/sq mt and popularly known as gsm.

Test Method : TAPPI T 410 or IS : 1060 (Part – I) 1987 are the reference for test method. Minimum 10 numbers of specimen of size 10 cm X 10 cm are cut, weighed and calculate the gsm by diving the area.

(b) Caliper of Thickness

Significance : Caliper is the measure of the thickness of a sheet of paper. Its units is mm or microns.

Test Method : The reference of test methods are TAPPI T-441 or IS: 1060-Part-I-1966. Thickness of test specimens are measured by using a calibrated micrometer.

(c) Water Absorptiveness of Nonbibulous Paper and

Paperboard (COBB Test)

Significance : Water absorbency is a characteristic pertaining to the sheets ability to resist water penetration and absorption.The details about test methods are prescribed in TAPPI T 441 and IS : 1060 Part – I – 1966. The test specimens are clamped, poured 100 ml. of water.Allowed to absorb water for 60 seconds. The water is removed after 45 seconds prior to 30 minutes, the additional water, is wiped and weighed. The difference in weight divided by sample area gives the value in gm/ml.

(d) Bursting Strength

Significance : To measure the force required to rupture the board when pressure is applied from one side.

Test Method : The sample is subjected to mullen bursting testing equipment and the force require to burst the paper is measured The test values are expressed as kg/cm2 or pound/sq inch or kilopaseals.

 (e) Burst Factor

Significance : The mathematical expression is as follows :

Burst Factor (BF) = (Bursting Strength(BS))/( Grammage (gsm)) ×1000

(f) Ring Crush Test (RCT)

Significance : The RCT of papers is defined as the maximum vertically applied compressive force on the rim of a circular ring of the paper without the paper buckling. Expressed in KN.

Test Method : RCT its measured according to TAPPI T822. In RCT. The test specimen is formed in ring, inserted into the holder as shown below. A top down load is applied on the strip of paper till it buckles.

(g) Corrugating Medium Test (CMT)

Significance : CMT is measure of the crushing resistance of a laboratory-fluted strip of corrugating medium. Unit is Newton. ‘N’ also called ‘Concora’.

Test Method : The reference test method is TAPPI T 809. The force at which the flute is crushed, is CMT value and can be read on the indicator. The single facer sample is kept in between the platen as shown in Figure.

 (h) Tensile Breaking strength

Significance : It is the maximum tensile force per unit width developed in a test specimen at rupture or break.

Test Method : Test specimen cut to specified size is clamped between two jaws of tensile tester. Then the two jaws move away from each other at a specific speed. The force at which specimen breaks is recorded. This test is conducted five times. The average breaking force divided by specimen width gives tensile strength in KN / m.

ii) Corrugarted Board

The following parameters are assessed in the laboratory for corrugated fibre board.

(a) Caliper

Significance : The thickness of corrugated board is the distance in millimeters measured between the two parallel contact plates of a micrometers between which the specimen is subjected to a pressure of 20 kpa.

Test Method : The reference of list methods are TAPPI T-441 or IS: 1060-Part-I-1966.

(b) Board Grammage by Ply Seperation Method

Significance : To determine the basic weights of the combined board and its components. As per TAPPI, the average readings are considered.

Test Method : The samples are soaked in water to allow the adhesive to dissolve in water. Then the layers of papers are peeled off to separate the layer carefully.

(c) Bursting Strength

Significance : To measure the strength properties of the board in terms of kg/ cm2.

Test Method : The sample is subjected to mullen bursting strength tester and the force required to rupture or burst the board is determined.

 (d) Puncture Resistance

Significance : The puncture resistance is a measure of the energy needed to punch through a material.

Test Method : The reference test method is TAPPI T 803. A pendulum with pyramidical shaped head, selected so as to simulate a corner of a box, is released from a certain height. The freely falling pendulum acquires kinetic energy and the head puncture the board. The energy consumed is expressed in ounce inch per tear inch or kg-cm.

(e) Flat Crush Test (FCT)

Significance : To measure of the resistance of the flutes in corrugated board to a crushing force applied perpendicular to the surface of the board.

Test Method : TAPPI T 825 or IS : 4006 – Part-I are the reference standards.Circular shaped CFB is kept in between the platen and compressed till rupture the flutes. Measure the force is measured in Kg.

 (f) Edgewise Compression Test or Edge Crush Test (ECT)

Significance : ECT of a corrugated board is defined as the maximum vertically applied compressive force along the edge of the board without the board bucking.

Test Method : The reference is TAPPI T 811. The sample is kept under horizontal plates with the flutes vertical. The plates are then passed down with a constant speed of 10 ± 3mm/minute so that the load on the edge of the board gradually increases. The load at which the board buckles gives the ECT. SI unit of ECT is KN/m.

(g) Performance Tests of Corrugated Fibre Board Boxes

(a) Box Compression Test (BCT)

Significance : This is the most important and the most common test for corrugated boxes. BCT is the measure of the ability of a corrugated box to take top down loads. It is the measure of stackability of the box and determines how much load can be stacked upon the box without the walls of the box buckling.

Test Method : TAPPI T 804 or IS : 7028 (Part-VI) are the reference test method for BCT. The box is placed in a press between two parallel plates which apply pressure to the box at right angles to its flaps. The bottom platen is fixed and the top plates moves at the speed at 10±3mm/min. Now, run the machine and continue till the box gets crush. Take the reading from the recorder in kgs.This will clearly indicate that how much force is required to compress the box.

(b) Drop Test

Significance : This test is conducted : To determine the ability of the package to stand up to rough handling, the degree of protection offered to the contents by the package and to compare the different types of packaging for the same product.

(c) Vibration Test

Significance : The aim of this test is to simulate the vibrations to which the box and its contents are subjected during transportation and to

- determine the effects on the box, the degree of protection offered to the contents by the package and to compare the different types of packaging for the same product.

Test Method : The test method has the reference of TAPPI T 817 and IS : 7028. Normally the package is vibrated for one hour duration at an amplitude of one inch for 120 cpm.

(d) Inclined Impact Test

Significance : This test is conducted to determine the ability of the package to stand up to rough handling, determine the degree of protection offered to the contents by the package and to compare different types of packaging for the same product.

Test Method : The reference test method is TAPPI T 801. 

The distance travelled or the speed at the moment of impact is noted. The test is repeated a certain number of times until there is a sign of damage.

(e) Rolling Test

Significance : To check the performance of the box during transit.

Test Method : The reference test method is DIN 55449. The full box is tipped over on its side. The test is performed according to the shape and the centre of gravity of package.

(d) Climatic Test

Significance : To check the performance of boxes at different climatic condition.

Test Method : The same packages area also subjected to 380C ± 10C and 90% ±2% RH and to observe the performances.

(e) Rain Test

Significance : The test is carried out to determine at what extent the package protects its components from the rain and to prepare the package for a test or a series of tests to determine the effect of rain on the performance of the package.