U. S. DEPARTMENT OF COMMERCE

HENRY A. WALLACE, Secretary

NATIONAL BUREAU OF STANDARDS

E. U. CONDON, Director

NATIONAL BUREAU OF STANDARDS MISCELLANEOUS

PUBLICATION M182

DEVELOPMENT OF STANDARDS FOR FLEXIBLE

CASELINING MATERIALS

By

BOURDON W. SCRIBNER, FREDERICK T. CARSON,

and CHARLES G. WEBER

Issued September 23, 1946

UNITED STATES

GOVERNMENT PRINTING OFFICE

WASHINGTON : 1946

For sale by the Superintendent of Documents, U. S. Government Printing Office

Washington 25, D. C. - Price 10c
PREFACE

Paper and paper products played a vital part in World War II One of the most important uses of such products was the safe

guarding against deterioration by moisture of supplies for ou:

armed forces scattered around the world. This is the chief func

tion of papers used to line shipping cases. To serve satisfactorily

they must be excellent moisture barriers, and, of course, remaii

intact under the stresses to which packaged materials are sub

jected. Because of the many adverse conditions under which ou

troops fought in this war, these requirements were particularly

severe. For this reason, this investigation was undertaken to as

sist in providing caseliners that would withstand the most ab

normal conditions of transportation and storage.

E. U. CONDON, Director.
CONTENTS

Page

Preface - ii

I. Introduction 2

II. Materials tested 2

1. Caselining materials 2

] 2. Base papers 4

3qH. Methods of testing 4

1. Standard methods 4

I 2. Special methods and apparatus 5

(a) Stiffness 5

(fo) Scuffing 5

(c) Creasing 7

i. (d) Water-vapor permeability 10

(e) Bleeding 11

I

r

. Test data . 12

'. Correlation of test data for caselining materials with

performance of caseliners made from them 17

\ . Recommended standards 22

DEVELOPMENT OF STANDARDS FOR FLEXIBLE

CASELINING MATERIALS

By Bourdon W. Scribner, Frederick T. Carson,

and Charles G. Weber

ABSTRACT

An investigation was made for the development of improved specifications for materials used to line shipping cases so that the liners would give

better service in overseas shipments of supplies, particularly those for our

armed forces.

The sheetings were given various kinds of tests considered to have a

bearing on their serviceability, such as strength, stretch, flexibility, resistance to puncture, scuffing, and permeation by water vapor and water. As a

part of the work, an improved cabinet for making water-vapor permeability

tests under accurately controlled atmospheric conditions simulating those of

the tropics was developed. This was so designed that the test specimens are

weighed inside the cabinet, thus obviating errors inherent in removing them

for weighing.

Packages containing liners, made of the same materials as the sheetings

tested, were subjected to simulated service conditions at a commercial testing laboratory. The packages were put through cycles of being tumbled in

a drum, dropped on a concrete floor, and bounced on a vibrator, with wetting,

under both tropical and arctic conditions. They were then examined for

permeation of moisture and for the condition of the liners.

Correlation of the test data of the sheetings with their performance in

the simulated service trials indicated that for the most satisfactory service,

the caseliners should be composed of sheets of kraft paper cemented together with asphalt, and that the important properties are areal weight of

paper and of asphalt, wet tensile strength, stretch, resistance to tearing

and puncture, and permeation by water vapor and water. Recommended

requirements for these properties are included.
2 Miscellaneous Publications, National Bureau of Standards

I. INTRODUCTION

At the request of the Container Coordinating Committee, War

Production Board, and with the assistance of funds from the

Board's Office of Production Research and Development, the

National Bureau of Standards participated in an investigation of

flexible caselining materials. The investigation was made for the

development of improved specifications for such materials so that

they would perform more satisfactorily in shipments of supplies,

particularly those for our armed forces.

The project comprised mainly (1) subjection of packed shipping

cases containing the materials as caseliners to simulated service

conditions at the Package Research Laboratory, Rockaway, N. J.,

(2) testing by the National Bureau of Standards of the materials

from which the liners were made, (3) correlation of the results

obtained at the two laboratories to determine the properties that

the materials should have to function satisfactorily as caseliners,

and (4) the formulation of recommended standards for the significant properties for use in purchase specifications.

The tests at the Package Research Laboratory were made as

follows: Standard wooden and fiber shipping boxes of different

sizes were lined with the caselining materials made into liners of

one-piece construction for "satchel" closure. The large boxes were

filled with cartonized hollow steel cylinders and wooden blocks

and the small boxes with wrapped hollow steel cylinders alone.

The closure of the liner was folded over and sealed with a moisture-resistant adhesive. The boxes were then put through cycles

of being tumbled in a revolving drum, dropped on a concrete floor,

and bounced on a vibrator, with intermittent spraying with water,

under both tropical and arctic temperatures. The boxes were

opened on completion of the cycles and the contents examined

for number of wet pieces, after which the liners were removed

and examined for holes, scuffs, or other damage. Detailed descriptions of these tests and accounts of the results obtained have been

published. \

2

, 3, 4 The following is a report of the tests made at the National

Bureau of Standards and of the correlation of them with the re- sults of the simulated service tests. Recommended standards

are included.

II. MATERIALS TESTED

1. CASELINING MATERIALS

The caselining materials tested consisted of 31 samples. There

were 24 asphalt-laminated kraft papers, made variously with

plain paper, paper infused with asphalt, paper containing waxy

materials, paper treated with melamine resin to improve its

strength and resistance to scuffing when wet, and paper treated

for mold resistance. Some of the papers were reinforced with

strands of fibers or cords imbedded in the laminating asphalt.

iH. A. Wolsdorf and E. G. Mullen, Modern Packaging 18, No. 9, 131 (May 1945).

2 H. A. Wolsdorf, Paper Trade J. 121, No. 4, 46 (July 26, 1945).

3 E. R. Stivers, Paper Trade J. 121, No. 4, 47 (July 26, 1945).

±H. A. Wolsdorf and E. G. Mullen, Modern Packaging 19, No. 4, 154 (Dec. 1945).
Flexible Caselining Materials 3

The remaining materials were made of other kinds of sheetings.

Detailed descriptions of these follow. The letters at the left are

the sample designations. The weights are on a basis of 3,000

square feet of material.

Asphalt-Laminated Kraft Papers

Duplex Uncreped

M—One 40-pound plain sheet, one 60-pound sheet infused with

wax resin compound.

D—One 60-pound plain sheet, one 60-pound sheet infused with

asphalt.

J—One 50-pound plain sheet, one 50-pound sheet infused with

asphalt.

S—One 50-pound plain sheet, one 50-pound sheet infused with

asphalt; embossed after lamination.

F—Reinforced, plain 30-pound sheets.

G—Reinforced, plain 30-pound sheets.

Duplex Creped

V—40-pound machine-creped sheets.

IH—40-pound machine-creped sheets.

;tG —One 30-pound plain sheet, one 60-pound sheet infused with

wax resin compound; creped after lamination.

K—One plain 60-pound machine-creped sheet, one 60-pound

machine-creped sheet infused with asphalt.

j T—One 60-pound machine-creped sheet, one 60-pound machinecreped sheet infused with asphalt.

>B—Two 50-pound machine-creped sheets, one sheet treated for

wet strength; wax applied to treated side.

| C—Reinforced, one 45-pound machine-creped sheet, one 75-

pound machine-creped sheet.

.U—Reinforced, 35-pound machine-creped, wet-strength sheets.

f lE—Reinforced, 45-pound machine-creped wet-strength sheets.

, Triplex Creped

IE—One 30-pound machine-creped sheet on one side; other sheets

3 plain, 30 pounds.

A—One 40-pound machine-creped outer sheet treated for mold

resistance, two 30-pound plain sheets.

C—One 60-pound machine-creped outer sheet infused with asphalt; two 30-pound plain sheets.

B—All sheets 40 pounds, outer sheets creped and infused with

asphalt before lamination, center sheet uncreped.

A.—All sheets 30 pounds, creped diagonally while being combined.

! H—All sheets 40 pounds, machine-creped and serrated.

1 —40 pound machine-creped sheets, outer sheets treated for

wet strength.

, D—40 pound machine-creped sheets, outer sheets treated for

wet strength, one outer sheet wax treated.

i V—All sheets 40 pounds, creped and infused with asphalt before lamination.
4 Miscellaneous Publications, National Bureau of Standards

1 Miscellaneous Materials

P—Duplex; uncreped, two 32-pound cellulose-wadding sheets infused with asphalt.

Q—Duplex ; uncreped, two 32-pound cellulose-wadding sheets I

infused with asphalt; one side coated with asphalt.

R—-Triplex; uncreped, three 32-pound cellulose-wadding sheets j infused with asphalt.

X—Lead foil laminated to one 30-pound plain kraft sheet. Foil I side coated with polyvinyl butyral, scrim cloth laminated I to kraft side.

Z—Cloth, one side coated with vinyl resin.

FF—Duplex ; one 40-pound machine-creped kraft sheet, one 22-

1

pound cellophane sheet.

II—Triplex; two 40-pound machine-creped kraft outer sheets,*

one 22-pound cellophane inner sheet.

2. BASE PAPERS

It was thought that tests of base papers used in the manufac-1

ture of the kraft caselining papers might, through correlation of I

the. results with the results of the tests of the caselining papers,!

yield information that would be of value to manufacturers in]

their choice of base papers.

Tests were made on 35 base papers used in the manufacture of I

17 of the caselining papers. The base papers were 15 plain and

9 creped laminating papers, 6 plain and 2 creped asphalt infusing

papers, and 3 asphalt-infused papers. The basis weights were

representative of the range generally used for laminated case-:

lining papers.

The following tests were applied to these papers, as far as the,

various kinds of tests are applicable to the different types of

papers: Weight per unit area and the thickness (the ratio of

which yields density), folding endurance, tearing resistance,

bursting strength, tensile breaking strength, air resistance;

smoothness, time of oil permeation, amount of oil absorbed, acidity, and kind and condition of fibers. Although the test values

for the different base papers varied widely, there was no significant relation between the properties of the base papers and the

properties of the caselining papers. For this reason the test data

for the base papers are not reported herein.

III. METHODS OF TESTING

1. STANDARD METHODS

The following tests were made according to the methods o1

the Technical Association of the Pulp and Paper Industry h

(TAPPI).5 The Association's designations of the methods are in

eluded : Basis weight, T 410 m ; tearing resistance, T 414 m ; burst!

ing strength, T 403 m; tensile breaking strength, dry T 404 m

tensile breaking strength, wet, T 456 m ; stretch, T 457 m ; wate^

resistance, T 433 m; water-vapor permeability at 73° F and 50!

percent relative humidity, T 448 m; water-vapor permeability a1 100° F and 90-percent relative humidity, T 464 m; resistance t( R

5 Copies may be obtained from the Association at 122 East 42d Street, New York 17, N. Y
Flexible Caselining Materials 5

puncture, T 803 m; and acidity, pH, hot extraction, T 435 m. The

wet tensile strength was determined on samples after they had

been immersed in water for 24 hours. Tearing tests could not be

made on reinforced papers because of the interference of the reinforcing material. As the apparatus for the puncture test is of

comparatively recent development, it might be well to explain

briefly that it measures the energy required to force a tetrahedral

puncture head (simulating the corner of a box) completely through

the test specimen. The rupturing force is provided by the release

of a heavy pendulum from a horizontal position. As the pedulum

swings down, the puncture head, carried at the end of a curved

arm attached to the pendulum and concentric with its bearing, is

driven through the specimen. The energy thus absorbed in puncturing the specimen is indicated by a pointer on a dial.

6

2. SPECIAL METHODS AND APPARATUS

The following are descriptions of the testing methods and apparatus for which no standards were available.7

1 (a) STIFFNESS

The stiffness test was used as a means of determining the

probable performance of the caselining materials in the folding

! operations incident to forming them into liners and to closing the

f liners. Excessive stiffness is undesirable. The method consists in

j finding the load required to force the material between two

s rollers. An apparatus devised for the purpose by M. L. Downs was

modified to permit its use in a standard type of paper tensile

strength testing instrument.

# The device, illustrated in figure 1, consists of two stirrups. A

i single stirrup, the cross bar of which is a V^-mch metal tube, is

1 fastened in the upper clamp of the tensile tester. An inverted

, double stirrup, which is fastened in the lower clamp of the tensile

, tester, has two %-inch rollers, separated by a distance of % inch.

The tensile tester, with pendulum weights removed, is calibrated

- over the desired range by hanging small weights to the upper

clamp (with the single stirrup clamped in place).

3 To make a test, the lower clamp of the tensile tester is run up

f until the tubular cross bar of the upper stirrup passes between

the rollers of the lower stirrup and comes below them. A specimen, 4 inches square, is then slipped under the rollers of the

double stirrup and over the tubular cross bar of the single stirrup.

The lower clamp is then run down, as in making a tensile test, the

specimen being bent and pulled between the rollers of the double

n stirrup. The force required to do this, which is determined from

the scale reading and the calibration of the tensile tester, is used

as a measure of the relative stiffness of the material tested.

ijl (b) SCUFFING

t The scuff test was used as a measure of the probable resistance

) of the materials to wear when rubbed against the walls and conitf ~~~~

7tt,

L' Beach> PaPer Trade J. 108, No. 5, 30 (Feb. 2, 1939).

V

\ The apparatus for creasing test specimens, for making the stiffness tests and the wet- hid tests, and the cabinet for water-vapor permeability at high temperature and humidity,

were developed by F. T. Carson and V. Worthington of the Bureau staff.
6 Miscellaneous Publications, National Bureau of Standards

12 3

I—: I I I SCALE INCHES

Figure 1.

Device for testing stiffness of caselining materials.

A stirrup having a single cross bar, B, is fastened by a tab, T, in the upper clamp

U, of a tensile tester. An inverted stirrup, carrying two rollers, R, is fastened in

the lower clamp, L. The Taber Abraser, shown in figure 2, is in common use for

testing many sheet materials other than paper for resistance to

abrasion. The apparatus consists of a horizontal motor-driven

turntable upon which the test specimen is attached, and two

weighted parallel arms, each carrying a special abrasive-filled

rubber wheel that rotates on the specimen under a given load. A

load of 1,000 grams was used for these tests. The two wheels re

volve in opposite directions and exert a combined abrasive, com

8 Paper Trade J. 119, No. 3, 24 (July 20, 1944).

9 F. T. Carson and V. Worthington, Paper Trade J. 84, No. 2, 45 (Jan. 13, 1927).
Flexible Caselining Materials 7

Figure 2.Apparatus used for determining resistance to scuffing of caselining materials

when dry.

pressive, and twisting action over a circular path. The turntable

was rotated until the surface of the material was just completely

removed, with continuous brushing of the debris from the specimen. The amount of material removed was determined by the

difference in the weight of the paper before and after abrasion,

and was calculated to revolutions per centigram of material removed. Only a dry-abrasion test was made; satisfactory results

could not be obtained on wet materials of this kind because of

their various water-resistant components. Even the dry-abrasion

test could not be applied satisfactorily to the cellulose wadding

materials because of the large amount of asphalt present.

The wet-rub tester shown in figure 3, has a metal plate on

which the test specimen, C, is clamped and rubbed by a chromeplated rounded end of a cylinder, F, projecting from a horizontally

reciprocating member that is weighted. For testing the caselining

materials, a load of 5 pounds was used. The number of double rubs

required to wear a hole through a specimen wetted with an excess

of water is recorded. The abrading surface of this apparatus is

not suitable for making dry tests.

(c) CREASING

The water-resistance and the water-vapor permeability tests

I were made on both uncreased and creased specimens. Tests on

:reased specimens are important because of the creasing of case-
8 Miscellaneous Publications, National Bureau of Standards

c —

1

©

D 1 r—[ p 1

r

» # i

-

\

1 A

V

s w ——pi

T LJ J 1 C

/

© !u o

a

12 3 4 5 6

i ,, i i i i i

' SCALE — INCHES

Figure 3.

Apparatus used for determining resistance to scuffing of caselining materials

when wet.

lining materials in forming and closing the caseliners and because

of the load on the creases after the container is filled. The materials were creased at low temperature because the caselining

operations are often done with very cold material, and asphalt

has a greater tendency to crack on creasing as the temperature

is lowered.

The test specimens before they were creased were exposed for

at least 2 hours to air having a temperature of approximately

40° F and a relative humidity of approximately 60 percent. The

conditions were chosen by the Task Group as being convenient to

use and suitable for the purpose. The test specimens were then

transferred to an insulated container, from which they were taken

one at a time for creasing. They were creased in a cabinet maintained at 40° ±2° F and having arm holes fitted with sleeves to
Flexible Caselining Materials 9

permit manipulation of the creasing apparatus. The specimens

were 4 inches square, and they were creased on two diagonals,

under a pressure of 2.36 pounds per inch of crease.

The creasing apparatus is illustrated in figure 4. A lower plate,

P, hinged at A, is lifted by a handle, H, until it contacts and lifts

the upper plate, R. Attached to the upper plate is a weight, W,

of such size that it and the upper plate together apply the required

load per inch of crease. The upper plate is held in position by a

guide until it is lifted. A stop, S, limits the movement. A square

Figure 4.

Apparatus for creasing caselining materials for tests for water and watervapor permeability.

of the paper to be creased is first wrapped along its diagonal

around a %-inch round rod (wood preferably) with diagonally

opposite tips held together, then the rounded section along the

diagonal is centered between the plates, and creased by depressing

the handle, H. It is held in position shown by dotted lines by the

catch, C, for the required time.
10 Miscellaneous Publications, National Bureau of Standards

(d) WATER-VAPOR PERMEABILITY

For making the water-vapor permeability tests, cells 3% inches

in diameter and about % inch deep were used. A flanged rim,

forming a shallow groove, provides a means of embedding the

perimeter of the specimen in the wax used to seal the specimen to

the dish, leaving a free area of 50 square centimeters through

which water vapor passes from the exterior to the desiccant

within. Each dish holds about 15 grams of 8-mesh anhydrous calcium chloride. The dishes were formed from disks of annealed

sheet aluminum 0.020 inch thick by pressing them between steel

dies.

The cells were first exposed and weighed at intervals in an

air-conditioned room maintained at 50 ±2 percent relative humidity and 73° ±3.5° F until they reached a steady rate of gain.

They were then transferred to a cabinet especially designed to

maintain the air within it at 90 ±1 percent relative humidity and

100° ±0.5° F and to obviate the necessity of removing the cells

for weighing them. The latter feature gives improved accuracy

in the determinations and reduces considerably the time required

for weighing.

The cabinet, illustrated in figure 5, consists -of a metal box,

14 by 14 by 14 inches, within an insulated box, a 1-inch air space

separating the two. Air is circulated in this interspace by a centrifugal fan in the bottom of the cabinet. A heater of about 80-watts

capacity and a thermoregulator in the interspace keep the envelope of circulating air at the required temperature. The inner

box is heated only by transfer of heat from the air in the interspace. In the bottom of the inner box are pans containing a saturated solution of monoammonium phosphate or of potassium

nitrate. A small fan blowing air on the pans circulates the air in

this enclosure and keeps it at a uniform humidity characteristic

of the relative vapor pressure of the solution. A port is shown

through which access is had to the pans, and another in the side

gives access to the test cells. Each port is sealed by an insulated,

rectangular plug held against a rubber gasket.

The test cells are hung by means of hooks to a notched disk in

the top of the inner box. A rod, hanging from the left arm of the

balance, passes through a hole in the floor of the balance and

through an aperture in the top of the cabinet, and ends in a hook

designed to engage the hooks supporting the test cells. The rod

is divided between the balance and the top of the cabinet, the two

parts being joined by a tab sliding in a sleeve. When the crank

at the left side of the balance is rotated a mechanism lifts the

weighing hook (together with the test cell just below it), locks

the two parts of the weighing rod together, and leaves the test

cell freely suspended from the balance arm ready to be weighed.

The disk supporting the test cells is fastened by means of a shaft

to a numbered disk on top of the cabinet, projecting from under.-!

neath the balance. The number on the numbered disk opposite the

pointer is the number of the disk in the weighing position. Any

number is selected by turning the disk. An interlocking device

holds the disk so that it can not be turned while a test cell is
Flexible Caselining Materials 11

' Figure 5.

Cabinet for testing for permeability to water and water vapor under

)

I tropical conditions.

J* being weighed. The cabinet has a capacity of 60 cells of the size

\ used.10

t

j It was found that 48-hour intervals of weighing over a period

I of about 2 weeks were satisfactory in arriving at a steady rate

I of transfer of moisture through the specimens.

(e) BLEEDING

The possibility of exudation at high temperature of asphaltic,

;

f

| waxy, or oily substances, used to impart water resistance and

lf'F. T. Carson and V. Worthington, Paper Ind. 27, 1799 (March, 1946).
12 Miscellaneous Publications, National Bureau of Standards

other properties to caselining materials, is of importance with

respect to damage from this source that might occur to the contents of shipping cases. Asphalt stains of course do the most

serious damage. Trouble from this source could be avoided by

using asphalt having a very high melting point, but such asphalt

would be more likely to crack when cold than an asphalt with a

lower melting point. For this reason, in choosing a temperature

at which to test for bleeding, it is necessary to use as low a temperature as is consistent with the highest temperature to which

shipments may normally be exposed in the tropics. It appears

that this would occur in the holds of ships where maximum

temperatures around 145° F have been recorded. Accordingly,

150° F was chosen as the testing temperature. The test specimens

were sandwiched between sheets of white paper, heated at this

temperature for 5 hours under a pressure of 72 pounds per square

foot, then the sheets of white paper were examined for kind and

degree of staining.

IV. TEST DATA

The test data for the physical properties of the materials, with

the exception of moisture resistance, and for acidity are given in

tables 1 and 3. The weight of asphalt is based on information

received from the manufacturers as satisfactory test data could

not be obtained. The test for acidity was made because it was

thought that the heat of the laminating process might cause deterioration of the materials if the acidity were too high. However,

with only a few exceptions the pH of the materials was 5.0 or

more, which indicates acidity that would not be harmful.

The test data for the resistance of the materials to water and

water vapor are given in tables 2 and 4.

Table 5 shows the results of the bleeding tests.
Flexible Caselining Materials 13

a £ .2 *i ^ -p

3

3

3

rC

E-1

3O

3 QO

g

5 =

bO g

H-3 -*H> * s

*

"8

co Jo. H «-

QO

Q

—05

H^> 55 m

3 3

bfl ^

.S c6

„co 53 Eh co

to co s s

CO HP £.22 3 CO

bO.3 3

bt

co f= m » Oo c3a

CO CO —

Q. g

.2 . c a m c §-g ««

N O X CO CO N

iONlOCOCO»C

fc.

OOHOOHCO rH H rH rH cm

co IS CO o o o o o o -o t- —i as oo ir^ ©

Doi 3t~ •^MNCOCCM

<o r5 GO o o o o o o © *ooomoocc

Z)ot rw UJONOOMN

rH o o © o o o t~ -hh CO to to CM

io oo co -*ti to co

o o o o o o cs> CO O i-i i— to CD

as cm os oo oo to

IO CO to CO "HH to

CM CM CO CO CM CM

rH i-l CM CM CM

NC13 05 00-C"H HH i—I CN CO

CM CD (M 00 CM

t-- CO O O rH

-rfl IO to Tfl CO

00 OO CO to o

OO to to CM i—i oo 00 co

o © o o t- OO T}< Tj< H^ "HH CO o o o © oo t- oo co

co co co

oo co co co as © CM CO CM CM -rjl CO

S©

Oh

00 to tO CO CO OS

CM CO CM CM CM

© CM © O0 CO CM

rH rH O © © tM< CM IO CO to NhcOOSHN rH CM i-H rH CM H

rS hh'hh rH P4 Ph

^Qr-^ajtHd

CNrHOSt^00-HH©t^00

CO^tO-rtitOncMCOtocO

O3C0i-H00©rHCO00© H CO H Tj( CO N H ijl «)

©©©©©©©©© COOOCO©<MOOCMO©

CNCO^tKM-HHtOOSHairH ©00©0©©0© CMCOi—lOlOHlCOO

cM-^tico©co<ot^coco

tOCOCM©lOOO©COO ©©©©©©©©©

MIN^HXCOOCCiH

OOCD-^inOCNCROi ©©©©©oooo

CMCMCMCOCMCM-rtitOiO

N >n CO N CO IO "3 h/ ifj

O5CO00COtO'H^COt>.lO

rHCMCMCMCOCMCOtO'crl

CMCMrHCO©02COtOCO

CMCMCOCMCOCMCOtOlO

COOOCDCMCO©CO©©

StOtOOTfiHCOOO

© © © © © © © 00 OO CO to

-hh CO CO CD Tti CO © © © o © © rH CM CO O CM CM CO CO CO to Ttl CO

*C0C0-*toO5©CM->*l H OS ri Tf OCN CO N CMCMrHCOCMrHCOCMcM

! rH

|WO i !pq ! !H

OS CM t>» CO to to

© © © OS 00 tO ^ 00 00

© © © CO CM IO OS CM

© © © t~ CO © tO to OS

© © © CM CM OS NCDN

© © © CO OS rH

i*< CD

© © © to to CO© CM CO

CO CO ^

© CM r«

co co

oo cm

CM CO © CM CM CO

pq

OO CO OO N O

t^- CO to CD

o © © © © © CM CM OS

rH CO CO to

© © © © © © O CO OO

t>. CM CO CO to

© © © © © CO OS © © to OO CO © CM

© © © © © CO CM CO oo

•H* to CO to Tf

t~ !>• OS CO © -rfl CM -rfl -rjl ^1

© OO t>- CO

co t-- to © OS

CM to IO

CM © to CM

© © © © © CO CM CM OO-iOSOlN

© © © © © OO OS CO

CO i—i t^. to

t"» to CO CO CO CM CO CO

© © to © © CO 00 00 to hihmcNh

NCO00NO CD CO rH CM © tO CO Tji CO

£rS,

<MOQri

-a

COft

C3 r

• ftrH

CD O

t«T-

=> C

co *J "2'"rg

rSS

3

w <o

CO >

3 'J3 .2

.-S"c3

CO i— a 3

3 ^2

' cu o3

CO

c« ©

'to tn"" CU D O coTJ "-"sis a

.3 «h 3 co

o o rt "h eu.S1

^> -o CO

ft, .flg

CO

*g

CO a>

CO

a3 co £> 2

O cc -s'§ °o

s s

O -r.

O ... °£

a M • S a

CO CO

*- IH ^ CO . *H

"grc £ £

w-3 jg II TM l~ C0Q

•g.9

CO

-rH CO ° O ^ - ^h3 ^ a, co o 5. 2-2 £

2 9

H

a g 1) 3 ..2^_S

I Q
14 Miscellaneous Publications, National Bureau of Standards

J3

TP

Ml

>>

as oj g.g

c3 ^

o.

i o

£ « c3

O

c

c

(N so so <m e«5 co

CO CO 00 O 00

tti CO t— <M CO SO

MlOTfOSDO

CO* i-H (M i-J i-H c<i

oo os co »» oo t>.

csi co oo os cs

+ + ONONU5© O OlOri

+++ OOONON O O O OS (N lO

+++

^m mwPh Ph

OtOI>05iHO)00 0!IN

OS 00 SO t— OOiQOlO^i

NCOMP5 00 00SOO

T-H t—I i—It—I^NHt-It—I

MH^OSOOrlnOS

HNNilOOOHNM

C^rt—IrtCIJNr-INN

OSSOlOi—lt^rt<i-HCOCNI

T-H t-H t—I t—lC<|i—IHH

rtNOONOOOnOOlO

NHiHrHMM'HT-IH

OCDOOi-lOOOMCqcO

Ni-IHrtNNHHH

+ OJ N 0O O Ol CO OJ rH If)

+

sooscoo-*iooo<r<io

^co-^o-<*<ir<icsicoco o•*=> SO+

^.-hV^PSPhPh'

|WO 1 icq ! \m

U5 »C SO

•<*< t» SO

I- o

oo SO lO

so co so co t>-

os r- m

+++

+++

++

+++

o o o o

PS

pq

SOOSSNJSOt^

CM OS OS O 00

(OTtirfNrH

<M SO CO i—i -«t<

00 SO SO ^ SO

tDOOONN

so oo os

CO "J OS 00 00 OHO ' <n"

© "i-H O rH

Ttl OS 00 OS o i-< o n

co oc t~ so-<*< o *<m'

++ +

+§++ O © O <N O O OS

++

+ ++
Flexible Caselining Materials 15

Acidity hot extrac- tion £3 »0 CO >o O t-H lO CD

Resistance

to

scuffing

Taber

dry

rub l CO CJ

«a<»

KlO CO tT-J lO

' CD

'53

rev/cg O t-< CO o CM —h >o CO

NBS

wet

rub CD Dou- ble rubs

3,100 3,300 4,000 2,600 9,000 430 700

MD Dou- ble rubs

3,800 3,600 4,700 2,800

13,000

550 690

Stiffness

CD

g> o o o d t-h O O Tfi co iO cm O O t-H lO

CM CD

MD g

700 660

1,000

200— 200— 330

Stretch

CD Kp CO-* «i *0 O t~- £5^ H t-H t-H CM t-H

MD kO i—1 CD CO oo »o lO

s" H CM t-H t-H T-H

Tensile strength retained

when

wet CD

v.O irj t-h t~ htJ< <M O OO

CO t~ OOt^ (McMr-H

MD Ko com coco t>. io tN t^ O ^'=D O CM CM

Tensile

strength

CD

lb

/in.

11.1 11.0 11.8 31.9 46.2 25.6 41.9

MD

lb

/in.

31.3 26.7 43.5 54.9 71.3 30.3 44.1

Tearing resistance

CD

<=> o o co

Os Oa O O o a: oa O OO T-H -Tfrl

MD

Os COOOCO ooCM OS ooo Oa Oa lO

CD !>. CD Oa CO T-H CO

Puncture

resistance Qo

Points 41 cm co co cm O CO CM CO

T-H CO q

Points 41 00 t-H t-H CM Oa CM CO

CM

Bursting strength £ t-H ITS CD US CO O

g oa oa eooo cMt^co

ft, f . ^

t

per

sq

ft

Asphalt OOT-H Ont-H

cogoo O (JS T-H co »o io ^; t-H

CO o ^ co" o

CO i c

"ft.SP.2

co H

us

CM

CM

'-3g

1*

o

-J3 TO P

I* i*

-T3 co

co -a

LO - —

tt-i 3 CO •~ s=s M «

co y3

co O

O o 1^"33 S

j "ce Is -2 a ft ft CO CO

--j o3 c*3 P

fcsn

o

*a3 a

i-ft

ft co

03 ro- Cl £3 '§1

r3.*=(

5 m .

• J—

1 _j CO t*^-S

t- e3 »

co „ i- Oh CO CO C3"2-C

ft CO "g

-+^» CD CO

>>a

'>

T3

03 00 —*h=!

CO

t-< CO

TO fH ftfto

c3 c?

CM

CMCM

<9 §

ft T3-2

CO 00

X JH -2 ft

ft co

-h 03 P

5

.S 03

CO T3

03

fH O

-2 ft co ft co ^3

• ri o3 co

O

1 tS3 &H&H

^2 ^ <4-l C O cH s >• sico .i; 50 a

© a? o cS

'-j3 "a3

'S3

»-

ftM P

CO

CO o

_rj t—co In °>

CO I

a

1:8

" —' CO

co T3 t3 o3 £ £ §^

-rt

o3 eg

co .2 73 'co '53 ^

HfM CO

3

"TOa

CO

H=!

I

CO

£5 -3 O c«

•43 -a o ^>

CO CO ^•^

K3 fe*

O g

•J CO n CO O 3

43 03 o o

00 co "3 CO

.5 to cS

rCS fl'C o o CO

03 -u 51 CO 2

Ir
Miscellaneous Publications, National Bureau of Standards

a_

bD

oa

>

T3a

3

03>

cd

a

i o

"2

t/3

s

12

j/3

s

T3a33

CD>

cd

ft

i ©

c3

a

"2

— o CM CD

T—

1

1—

t

CO CO o o - CSI

00

CN o ©

CO O

©

o

oo

00

-

CXI

CO 00 o • US U5 CO

CM CO © Oi

O0 <N Oi

3

o

T3a

OS »0

r-J © CM

©

© OS

© © csi csi

3

©"

T-l ©

© oi csi ©_

csi

T3a

i. 3

CD CD g

>

CO '53

Ui CD

CD O

Cd CD ©

"2

+ + + + © © © © ©

Q

+ + + + +

o

CD -a

3

"2

+ + + ©©

© © ©

H

o o

oo

CO

oo + + © ©©

+ +

3

-ain

oa

CS>

cd

CD ©

CD Cd cd a

3

K

cd

CD —

cd ,3

3 a

3 *

.a s*

? CD

°>m sO

|§

o 0.8

cdo

^CD CD "a a Q

Cd 3a

cd .3

-O

CD

B33

3

'3

cd

CD

03 _o

"3

cd J3a

T3

-a

T3

cd

it

CD T3 J3o

— 13 '8.8

rS a ^ 1

cd —a

.a j=

cd -3a

*T3

CD — in 3

acdft- 5 £-2 42 -S

C3 .5 2

ft3

Q

s a ft-S a » ft w

2 c«

CD3O

oO

3

cd J3 « &

'a'cD s « Q

a »

a s —cd cd

' J3 a—

cd o> a «*

42*—

cd o

a °

c^

£ S

cd CD 3 3

."2-8

co cd a a

cd j-

-O

a> cd cd-o c ft, O" 05 X
Flexible Caselining Materials 17

Table 5.

Bleeding tests of caselining materials

Sample

designation

Nature and degree of staining of white paper in contact with

both sides of test specimens at 150° F and under pressure of

72 pounds per square foot for 5 hours

A.... B ... C

D... E

F

G.... H. .. J

K...

M.... O.... P....

Q...

R... S

T...

XL...

V.... W... AA.

BB.

CC

DD

EEL. FF.. GG.

HH.

II....

Slight asphalt staining, spots ; brown wax stains

Moderate asphalt staining, streaks.

No staining.

One side considerable asphalt staining, spots ; other side (infused) slight asphalt staining, spots.

Slight to moderate asphalt staining, spots.

No staining. Do. No asphalt staining, brown wax spots. Do. One side moderate asphalt staining, spots ; other side (infused)

slight asphalt staining, spots.

No asphalt staining, brown wax spots.

Moderate asphalt staining, streaks.

One side no staining ; other side slight asphalt staining ; test paper sticks partly to caselining material.

Considerable asphalt staining ; test paper sticks to caselining

material.

Considerable asphalt staining ; test paper sticks to caselining

material.

Infused side, considerable asphalt staining ; other side, slight

asphalt staining.

Infused side, considerable asphalt staining ; other side, no

staining.

No staining. Do. Moderate asphalt staining, streaks.

Very considerable asphalt staining. Test paper laminated firmly

to caselining material.

No asphalt staining, slight wax stains.

Moderate asphalt staining, spots. Test paper sticks around

edges of caselining material.

Very considerable asphalt staining. Test paper laminated firmly

to caselining paper.

No staining.

Slight asphalt staining, brown wax spots.

No asphalt staining, brown wax spots. Do.

Slight asphalt staining on one side ; other side brown wax spots.

V. CORRELATION OF TEST DATA FOR CASELINING

I MATERIALS WITH PERFORMANCE OF

CASELINERS MADE FROM THEM

Determination of the significance of test data is necessary in

arriving at a quality standard for any material. In the present

instance, judgment of performance was based on results of the

tests of the packed snipping cases at the Package Research

Laboratory.11 There the different materials were given ratings

based on how well they survived the simulated service tests. The

rating was made by a system of scoring with respect to the occurrence of holes and tears. A score of 6 was the maximum, indicating fewest failures; a score of indicated the poorest performance. Caseliners A, C, K, W, and Z were given a score of 6;

liners V and CC, a score of 5 ; and liners H, O, T, U, DD, and EE,

a score of 4. These three scores were characterized as indicating

satisfactory performance. The remaining caseliners, which received scores of 2, 1, and 0, were classed as unsatisfactory.12 A slightly different method of rating the caseliners is shown

in table 6. This rating is based on the same data used in the

above classification, with the addition of columns 7 and 8 of the

11 See footnotes 1, 2, 3, and 4.

12 See footnote 4.
18 Miscellaneous Publications, National Bureau of Standards

table, but was arrived at by a different method of handling the

data. In table 6 the liners are arranged in the eight numbered

columns according to excellence of performance in the simulated

service tests made at the Package Research Laboratory. The

composite-rating value of each liner, shown in the last column, is

the sum of the 8 position numbers of the liner in the 8 numbered

columns. The first 13 liners in table 6 are the same 13 liners that

were classified independently as satisfactory by the score method

referred to above, but the order within both the "satisfactory"

group and the "unsatisfactory" group is somewhat different. In

the subsequent discussion the "satisfactory" group, which includes the same liners by either method of classification, will be

called group I; the "unsatisfactory" liners will be called group II.

Table 6.

Relative rating of caseliners according to simulated service tests

Average number of Weighted average Liners with no holes Contents

holes and tears number of holes or tears dry

Position Composit No.

1 2 3 4 5 6 7 8 rating

Tropic Arctic Tropic Arctic Tropic Arctic Tropic Arctic % % % %

1 0.0 C 0.0 0.0 c 0.0 100 c 100 100 A 100 Z 25 Z .1 W .1 T .1 Z .2 T 93 W 93 R 100 c 100 w 28

3 T .1 Z .2 Z .3 W .3 Z 87 Z 90 P 93 K 100 48

A W .3 V .3 W .9 A .8 w 80 A 80 Z 92 W 100 K 51

5. EE .3 A • 4, EE 1.5 K 1.6 EE 80 K 73 W 87 Z 96 C 60

6. R .3 H .4 R 2.1 V 1.9 K 67 V 73 DD 87 BB 93 A 62

7 U .8 K .4 DD 2.5 DD 2.5 R 67 cc 73 EE 87 DD 93 DD 70

8 K .9 EE .5 K 2.9 GG 2.6 U 53 H 67 A 80 HH 93 EE 70

9 CC 1.0 U .5 C 3.6 HH 2.9 DD 53 U 67 K 73 II 93 H 85

10 DD 1.0 .5 H 4.8 H 3.1 c 50 EE 67 Q 73 D 87 T 89

11 H - 1.2 CC .5 U 5.1 EE 3.5 cc 40 60 U 73 O 87 U 91

12 Q 1.6 DD .7 A 5.7 O 3.8 H 33 DD 60 cc 53 T 87 CC 91

13 A 1.7 GG .7 CC 7 T 4.1 Q 27 HH 60 H 50 X 87 V 103

14 B 1.8 HH .8 Q 8 CC 4.1 B 27 D 47 HH 47 cc 87 R 117

15 C 2.2 T .9— B 10— U 4.7 A 20 M 47 II 47 H 80 HH 128

16 S 2.7 B .9 P 10 D 7— P 20 GG 47 AA 40 M 80 GG 132

17 P 2.9 M 1.1 GG 10 BB 7 V 13 BB 40 V 33 V 80 B 135

18 V 4.2 BB 1.1 V 11 B 7+

9 AA 13 B 33 X 33 GG 80 P 152

19 AA 5.2 D 1.3 HH 11 M GG 13 J 33 GG 33 EE 73 Q 154 20 BB 5.3 J 1.4 AA 13 J 10 D 7 T 33 B 30 B 67 BB 154

21 HH 6.1 AA 1.7— S 23 AA 13 E 7 E 27 c 30 U 67 D 155 22 GG 7.2 R 1.7 BB 24 E 13+ S 7 AA 20 T 27 E 60 AA 165

23 E 12.4 E 1.9 X 26 II 15 F Q 7 J 20 J 60 M 173 24 D 13.1 P 2.7 D 28 R 17 G R 7 FF 20 FF 60 J 182

25 II 13.6 Q 3.6 E 34 X 21 J P M 13 P 53 II 187

26 J 21.1 II 4.1 J 34 P 24 M S BB 13 R 47 X 189 27 X 25.0 S 4.2 M 38 S 27 X X S 7 S 47 s 193 28 M 28.2 FF 19.5 F 49 Q 35 BB FF D AA 47 E 195 29 FF 32.5 X 19.7 II 60 FF 53 FF II E Q 33 FF 221 30 F 35.4 F FF 127 F HH F F F 231

31 G 341. G G 358 G II G G G G 241

In table 7 the caseliners are listed in the order of performance

according to the composite rating of table 6, and the corresponding physical properties, determined by tests made at the National

Bureau of Standards, are tabulated. The data given are averages

of the values in the machine direction and in the cross direction,

or averages of values for the two sides of the liners (according

to the nature of the tests), obtained from tables 1 to 4. There is
Flexible Caselining Materials 19

one exception; the Taber abrasion value given for each liner is

the minimum value obtained on the two sides of the liner.

Table 7.

Average values of physical properties^ of caseliners, arranged in order of

composite rating {table 6)

Sample

Designation Bursting

strength

Puncture Tearing

Tensile strength

Wetresist- resist- tensile Stretch Stiffness ance ance strength

Resistance to

scuffing

NBS

wet

Taber

dry

(min)

Water

resist- ance

creased

at 40° F

Water-vapor

permeability

at 100° F, 90

percent

relative humidity

creased

GROUP I

Points Beach 9 lb/in. lb/in. % a Hundred rev/eg hr (g/m^/24 hr

units oscilla- tions z 125 304 790 59 66 16 200— 110 115 10 84 w 124 53 640 51 19 10 820 6 48 21 19 117 228 1,010 55 26 23 980 6 22 60 16 K. 110 53 565 49 12 10 870 11 24 50 10 c 110 70 42 15 10 710 8 13 26 13 A 80 182 715 30 15 26 495 29 42 100+ 3 DD 98 250 845 51 21 16 790 3 16 80+ 9 EE 116 62 50 24 11 845 22 . 24 31 17 H 95 44 475 40 10 15 705 12 22 85+ 8 T 110 40 435 47 15 11 550 4 8 46 47 U 104

88 54 42 24 5 725 20 30 29 16 CC 45 540 57 16 6 845 10 17 80+ 7 V 57 65 355 30 6 15 325— 2 15 15 18

GROUP II R—

HH_

GG.

B__.

P-__ Q~-

BB.

D__. AA.

M_.

J..

II _ X_

S..

E_.

FF_

135

61

97

9169

11277

110

100

80

86 108

71

10372

612935

41

5136

32

28

2632

100

2330

22

4630

350

355

415

780

850 330

475

470

425

410

375

335 405

190

28

3336

39

21

1934

7147

68

6343

43

5652

28

57

51

30

8

111315

18

910

11

6

9 30

10

6

1315

1610

6712

20

12

4

4

4

4

114

55

13

34

750 465—

340

425

555

500 440

1,020 590

750

770 490 200—

630

645

200

700 440

44

114

6 35

35

6

9

9

727

6567

10

910

117

19

6

1114

85+

4144

6090+

100+

23

13 100+

80+

90+

26 100+

39 100+

55

17

11

1 All tests made at 73° F, and 50-percent relative humidity, except water-vapor permeability,

are averages of both directions, or of both sides. Values, except Taber

As the performance rating, by either method, is based largely

on the development of holes and tears during the simulated

service tests, the correlation of the simulated service tests with

the physical properties of the liner material must logically be a

correlation with the results of those tests of physical properties

that apply stresses intended to produce some form of failure by

rupture or wear. That there is some such correlation is indicated

by the fact that it is possible to choose a combination of tests

and limits of test values that will separate completely group I
20 Miscellaneous Publications, National Bureau of Standards

from group II. For example, a puncture resistance (Beach) of not

less than 40 units; a tensile strength of not less than 30 pounds

per inch; a stretch of not less than 5 percent; and a tearing resistance of not less than 355 grams will do this. All liners in group

I will be retained under this combination of physical-property

requirements. All but seven liners in group II will be eliminated

by the first requirement; three of these seven will be eliminated

by the second requirement; two of the remaining four, by the

third requirement; and the remaining two, by the fourth requirement.

Of course, such a procedure is an elastic and arbitrary one, in

that some other combination could be found that would divide the

liners at a different level. It is apparent, however, that a reasonable specification of physical properties might be drawn up that

would retain unequivocally most of the satisfactory liners, while

eliminating equally unequivocally most of the unsatisfactory

liners. The few liners that are a little difficult to place definitely

in one group or the other, by their physical properties, are naturally those near the division line of table 7, between groups I and

II. For example, liner R performed very well in the simulated

service tests, while under tropical conditions, but performed poorly

under arctic conditions. To make such a distinction by physical

properties alone would require that certain tests to failure be

made on the liner materials at a low temperature, under which

condition the asphalt becomes brittle, but no such tests were made

at the National Bureau of Standards. It is observed, however,

that all the liners of this construction (P, Q, and R) are weak in

tension under normal conditions, which provides a means of

eliminating them by a tensile requirement. Then there are some

liners above and below the division line that did not differ much

in performance in the simulated service tests, when ranked according to table 6. Liners V, HH, and GG are similar in structure,

and are comparable to one another in most physical properties.

The propriety of regarding one of these as satisfactory and the

other two as unsatisfactory may reasonably be questioned.

The physical properties tabulated in table 7 are useful in varying degrees in separating the two groups. All liners of group I

(first 13 in table 7) have a puncture resistance (Beach) of 40

units or more ; only five (tests of R and Q not having been made)

in group II exceed this value. Of the liners in group I on which

tests of tearing resistance could be made, all but one tested 435

grams or more; only four of those in group II exceeded this

figure. Although tearing resistance is useful as far as it goes,

satisfactory tests can not be made on many liners containing

cloth, strands, or long fibrous material. For this reason, it is not

very desirable to use tearing resistance in a specification if it

can be avoided.

A bursting strength (Mullen) of 80 points or more was found

for all liners in group I, with one exception ; but two-thirds of the

liners in group II also have bursting strength values above this

figure. Bursting strength, therefore, is not very useful in separating the two groups. Likewise, the range of tensile-strength

values is so much alike in the two groups that this property might
Flexible Caselining Materials 21

be dismissed as of little value, except for one consideration. As

previously stated, the liners P, Q, and R, made of cellulose wadding

infused with asphalt, were classed as unsatisfactory because of

their very poor performance under arctic conditions. The only

.physical test made at normal temperature that will eliminate

these liners is tensile strength, and this fact appears to be the

only logical reason for including the tensile test in the effort to

separate group I and group II by their physical properties alone.

The tensile strength of the liners when wet is, on the other hand,

more useful. All but three of the satisfactory group have a wet

tensile strength of 15 pounds per inch or more ; only three of the

unsatisfactory group exceed this figure. Stretch is also useful.

Only two of the liners in group I have a stretch of less than 10

percent; about two-thirds of the liners in group II have a stretch

of less than 10 percent.

Stiffness apparently has no bearing on the separation of the

two groups. This might be expected, because a test of stiffness

does not involve rupture or wear.

It was expected that the "wet-rub" test would be related to the

separation of the two groups, inasmuch as the scuffing of the

wet liners, and the wearing of holes through them, are the very

essence of some of the simulated service tests. It is apparent,

however, from the data in table 7 that the corresponding test on

the liner materials has little relation to the separation of the two

groups. The Taber abrasion test on the dry surface does, on the

contrary, appear to help in the classification, provided that the

minimum value for the two sides is used. All but two of the satisfactory liners have a minimum Taber value of 15 or more revolutions per centigram of material worn away; only two of the unsatisfactory liners have a minimum Taber value exceeding this

figure.

Resistance to the transfer of moisture through the liners, although it probably had no direct bearing on the simulated service

tests, is of primary importance in its own right, since the chief

function of a caseliner is to serve as a moisture barrier. A liner

may withstand all necessary rough treatment without injury,

and still be inherently unable to protect the contents of a shipping

case against damage by moisture. The values for water resistance

and for water-vapor permeability are given in table 7. Very few

liners in either group (but some in both) have a water-resistance

-value less than 20 hours. The water-vapor permeability is the

only test listed for which the degree of excellence is inversely related to the numerical value given. In group I, all but two liners

have a water-vapor permeability of 19 grams per square meter

per 24 hours or less at 100° F and 90-percent relative humidity;

in group II the liners were equally divided on each side of this

figure.

The following combination of physical tests and limiting values

seems to provide a reasonable basis for selecting satisfactory

caseliners.

Puncture resistance (Beach), average of both directions, not

less than 40 units.
22 Miscellaneous Publications, National Bureau of Standards

Tensile strength, average of both directions, not less than 30

pounds per inch width.

Wet tensile strength, average of both directions, not less than

10 pounds per inch width.

Stretch, average of both directions, not less than 8 percent.

Water resistance, on creases made at 40° F, average of both

sides, not less than 20 hours.

Water-vapor permeability at 100° F and 90-percent relative

humidity, on creases made at 40° F, not more than 20 grams per

square meter per 24 hours.

If it is desired to add some additional safeguard, it may be

useful to add an abrasion value by the Taber instrument of not

less than 10 or 12 revolutions per centigram on either side.

Based wholly on tests of physical properties, such a combina- i tion as that given above eliminates with little uncertainty the 1 caseliners in group II, while retaining all but five in group I. Of i these five, three (Z, T, and V) fail because they are not good

enough as moisture barriers; the other two (U and CC), because

of low stretch.

VI. RECOMMENDED STANDARDS

In a meeting attended by the Task Group and representatives

of the War Department, the Navy Department, and the National

Bureau of Standards, it was agreed that:

1. It is possible to correlate National Bureau of Standards

physical tests on caseliner materials with performance results on

caseliners made from them tested at Package Research Laboratory.

2. Based on such correlation, and without taking into account

load, box construction, box size, and handling, a satisfactory caseliner material can be defined as follows:

The caselining material should be asphalt-laminated kraft paper

having the following properties:

Total asphalt per 500 sheets, 24 by 36 inches, not less than

150 pounds.

Total kraft paper per 500 sheets, 24 by 36 inches, not less

than 90 pounds.

Stretch, average of both directions, not less than 10 percent.

Tearing resistance, average of both directions, not less than

400 grams.

Tensile strength, average of both directions, not less than 40

pounds per inch width.

NOTE.—Variations below the minimum tensile-strength requirement are

permissible, provided they are compensated by an increase over the tearing

strength requirement in the ratio of 10 units of tearing strength to 1 unit

of tensile strength.

Puncture resistance (Beach), average of both directions, not

less than 40 units.

Water resistance, on creases made at 40° F, average of both

sides, not less than 16 hours.

Water-vapor permeability at 100°F and 90-percent relative

humidity, on creases made at 40° F, average of both sides, not

more than 20 grams per square meter per 24 hours.
Flexible Caselining Materials 23

In the foregoing specification, the tensile-strength requirement

is coupled with the tearing-resistance requirement in a manner

that seems rather awkward and strained, in order not to eliminate

obviously good liners that have a tensile strength of less than

40 pounds per inch. It has already been pointed out that tensile strength, with one possible exception, seems to have very

little relation to the classification of liners by the simulated

service tests. As the specification confines acceptable caseliners

to those composed of kraft paper, laminated with asphalt, it becomes unnecessary to include a tensile-strength requirement

solely to eliminate those miscellaneous liners (P, Q, and R) found

unsatisfactory under arctic conditions. It is recommended, therefore, that the tensile-strength requirement, and perhaps also the

requirement for tearing resistance, be omitted, and that a wettensile-strength requirement of not less than 10 pounds per

inch, be substituted for them.

The project was carried out with the assistance of a Task

Group, representative of manufacturers of caselining materials

and the Forest Products Laboratory, which acted in an advisory

capacity. The Task Group was appointed by Henry A. Wolsdorf,

chairman of the Container Coordinating Committee. His invaluable assistance and that of the following members of the Task

Group throughout the investigation at the Bureau is gratefully

acknowledged:

E. G. Mullen, chairman, W. Ralston & Co., Inc.

C. E. Hrubesky, Forest Products Laboratory.

F. F. Newkirk, American Reinforced Paper Co.

H. J. Driscoll, Union Bag & Paper Corporation.

W. S. Seaman, Angier Sales Corporation.

M. L. Downs, Thilmany Pulp & Paper Co.

Washington, December 21, 1945.

-fr U. S. GOVERNMENT PRINTING OFFICE: 1946 697586

I

I