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MICHIGAN STATE UNIVERSITY
COLLEGE OF HQME ECOI'TOMICS

'j. _ EAST LANSENG, MICHIGAN

r)

ABSTRACT

A/éOME RELATIONSHIPS BETWEEN ABRASION RESISTANCE AND
TUFT HEIGHT IN SELECTED TUFTED CARPETS OF ONE
HUNDRED PER CENT POLYPROPYLENE SURFACE YARNS

by Patricia J. Murphy

Three single level tufted carpets of 100 per cent
polypropylene surface yarns, each having a different tuft
height, were selected for this study. Other factors,
including tuft density, tuft type (cut or loop), and
yarn twist, were held as constant as possible. No attempt
was made to control the price of the carpet or the manu-
facturer of the fiber and/or carpet. The carpets selected
were obtained from a manufacturer and local retail stores
in Lansing, Michigan. The price of the carpets was within
the medium range for polypropylene carpets; one sold for
$5.95 per square yard and two for $6.95 per square yard.

All laboratory testing was done under standard con-
ditions using methods set forth in ASLM. Preliminary
testing was performed prior to the beginning of this
study, using a fourth carpet to standardize all testing
procedures. The tests performed included fiber verifica-
tion, by burning, solvents and cross-sectional and longi-

tudinal microscopic observation; yarn twist; total carpet

Patricia J. Murphy

weight, pile yarn weight and backing weight; loop length;
tuft density; and abrasion resistance. The specimens were
abraded with the Taber Abraser for 50, 100, 300, 500, 750,
1,000, 1,500, 2,000 and 3,000 cycles and the number of
cycles required to reveal the backing material. The weight
loss was determined at each of these ten levels of abra-
sion.

The weight loss was found to be significantly different
at the .05 level of confidence when an analysis of vari-
ance was performed on the data. A .005 level of confi-
dence was found for the weight loss at the endpoint and
for the number of cycles required to reach the endpoint.
The Duncan's Range Test was applied to the data to deter-
mine which carpets were significantly different from the
others.

Although the study was too limited in scope to draw
any conclusions concerning the abrasion resistance of
tufted carpets of 100 per cent polypropylene surface
yarns, the three carpets selected for this study were
considered low in abrasion resistance, using change in
visual appearance as the criterion. Approximately 150
to 200 milligrams of weight were lost at 1000 cycles of
abrasion. This is within the "excellent" weight loss
range of a classification set up by Thruslow; however,

it does not take into consideration the fact that poly-

Patricia J. Murphy

propylene is the least dense of all fibers and consequently,
the amount of fiber in 150-200 milligrams of polypropylene
constitutes a fairly large volume. The visual appearance
of the carpets changed markedly when the samples were sub-
jected to very few cycles of abrasion. Even with fifty
cycles of abrasion, the carpets showed broken and brittle
filaments. By 100 cycles, enough dyestuff had deteriorated
to cause the fiber ends to be white and the color change
was very objectionable after 300 cycles of abrasion. At
the 500 cycle level, the path of the calibrade abrasive
wheels was worn below the surface of unabraded areas of
each specimen.

The difference between the loop length of the high
and low carpets and the high and medium carpets used in
this study was considered sufficient to reveal a signifif
cant difference between the abrasion resistance of these
carpets. The high and medium tuft height carpets did not
show a significant difference in resistance to abrasion.
This is probably not only due to the fact that the carpets
of medium and high tuft heights were closer in loop length
than those of medium and low tuft heights, but also to the
fact that the loops of the carpet of high tuft height were
leaning to one side and so received a somewhat different

type of wear than those carpets with upstanding loops.

SOME RELATIONSHIPS BETWEEN ABRASION RESISTANCE AND
TUFT HEIGHT IN SELECTED TUFTED CARPETS OF ONE
HUNDRED PER CENT POLYPROPYLENE SURFACE YARNS

By

Patricia J. Murphy

A.PROBLEM

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF ARTS

Department of Textiles, Clothing and Related Arts

1968

ACKNOWLEDGMENTS

The writer would like to express sincere gratitude
to all those who have made this study possible. The cooper-
ation of faculty, friends and the participating manufac—
turers of polypropylene carpets is especially appreciated.

The writer wishes to thank Dr. Mary L. Gephart for
her interest and support. The encouragement given by Dr.
Gertrude L. Nygren is most appreciated. Mrs. Stephenie
‘Winkler has been very helpful in providing guidance. Mrs.
Nixola F. Bayle has been especially understanding and
willing to assist whenever possible. Mrs. Kathryn B.
Riedel has given very generously of her time to this study
and has been extremely helpful throughout its entire devel-
opment. Miss Sandra J. Woolum has provided much of the
necessary moral support. The continuous effort of these
people and many others has led to the realization of this

project.

ii

TABLE OF CONTENTS

ACKNOWLEDGMENTS. . . . . . . . . . . .

LIST OF
LIST OF

Chapter
I.
II.
III.
IV.

V.
VI.
VII.

TABLES O O O O O O 0 O O O O O
FIGIJRES. O O O 0 O O O O O O 0

INTRODUCTION . . . . . . . . .
REVIEW OF LITERATURE . . . . .
DEFINITIONS OF TERMS . . . . .
EXPERIMENTAL PROCEDURE . . . .
Selection of Carpets . . . .
Preliminary Study. . . . .
Laboratory Test Methods. . .
DISCUSSION OF TEST RESULTS . .
CONCLUSIONS. . . . . . . . . .

SWARY O O O O O O O O O O O 0

LITERATURE CITED . . . . . . . . . . .

A-PPENDIX O O O O O O O O O O O O O O 0

iii

Page
ii

iv

1%
l7
l7

18
18

29
38
M2
L+5
#8

LIST OF TABLES

Table Page

1. Carpet Thickness in One—Thousandth Inch
Units Under 0.025 Pounds of Pressure as
Measured With the Schiefer Compressometer
for Three Selected Tufted Polypropylene
Carpets. . . . . . . . . . . . . . . . . . . 31

2. Number of Tufts Per Inch for Three Selected
Tufted Polypropylene Carpets . . . . . . . . 32

3. Average Cumulative Weight Loss in Milligrams
for Three Selected Tufted Polypropylene
Carpets. O O O O O O O O O O O O O O O O O O 33

H. Analysis of Variance at Selected Abrasion
Cycle Levels for Three Tufted Polypropylene
carpets. O O O O O O O O O O O O O O O O O O 36

5. Duncan's Range Test of Significance at

Selected Abrasion Cycle Levels for Three
Tufted Polypropylene Carpets . . . . . . . . 37

iv

Figure

I.

LIST OF FIGURES

Average Cumulative Weight Loss in Milli-
grams at Selected Cycles of Abrasion
for Three Polypropylene Carpets. . . .

Page

35

CHAPTER I
INTRODUCTION

One of the most recent developments in the textile
field which has had especially important implications for
carpeting has been the introduction of the synthetic
fiber, polypropylene. Polypropylene is a member of the
chemically inert alkene (olefin) series of hydrocarbons
and is composed of long-chain propylene units (-gE-CH2-).
The polymerization of isotactic polypropylene was patented
in 195% by professors Natta and Zeigler and the production
of polypropylene as a textile fiber was begun by Monte—
catini of Italy. (12,p.l7l) American manufacture of the
fiber was undertaken in 1958 by Hercules Powder Company
(ll,p.529), and by 1962 multifilament yarns and staple
fibers were first made available for commercial use in
home furnishings markets, apparel trades, and for indus-
trial applications. (l2,p.180)

The first polypropylene carpets were produced in
1962 by the needle felt method. Because of the extra-
ordinary resistance of polypropylene to moisture absorb-
tion, the carpets of polypropylene were suitable for uses
uncommon to carpeting materials in previous years. Poly-

propylene carpets were sold for use in kitchens and

l

bathrooms, where spills and stains might be frequent, as
well asfor use in other rooms in the home. The introduc-
tion of polypropylene as a carpeting material took carpet-
ing out of doors. Being almost completely unaffected by
moisture, this carpet fiber could be used on patios,
around pools, on ship decks or any other area which might
be subjected to water and dampness.

Some manufacturers now produce a polypropylene car-
pet fiber resembling grass, and these carpets are in use
as lawns, golf greens and athletic fields since poly-
propylene carpet yarns can withstand approximately 1,000
times as much abrasion as grass and need no care. Besides
the felted and grass-like forms, polypropylene yarns
presently are available in braided rugs and tufted car—
pets. (9,p.25)

Tufted polypropylene carpets for home use were
introduced in 1965 and this construction technique has
made the new fiber a competitor of nylon and acrylic
carpet fibers. In 1966, polypropylene claimed h per cent
of the carpet market and 2 per cent of the total synthetic
fiber market. (15,p.101)

According to Textile Industries, February, 1967,
the consumer desires several characteristics to be present
in a carpet considered suitable for residential purposes.
These conditions include:

reproducibility and uniformity

crush resistance
durability

resistance to pilling and fuzzing

aesthetic appeal

flame resistance

soil resistance

lightfastness

washfastness

anti—static properties (15,p.98)

Abrasion resistance has been chosen for this inves-
tigation of polypropylene carpets. Carpet fiber dura-
bility, or abrasion resistance, is dependent on the
strength inherent in the fibers as well as the structural
characteristics of the carpet. The structural elements
important in determining the degree of resistance to
abrasion are tuft density, tuft height, tuft type (cut
or loop), and yarn twist. (3,p.37)

The hypothesis is that carpets of a similar poly-
propylene fiber content, tuft density, tuft type and yarn
twist, but with a higher tuft height, have a greater
abrasion resistance than carpets with a lower tuft height.
The assumptions are that the carpets selected for use in
the present study were of comparable construction and
yarn quality and varied only in tuft height. The objec-
tive of the study is to determine some relationships
between abrasion resistance and tuft height in selected
tufted carpets of 100 per cent polypropylene surface
yarns.

A review of current literature on carpets has

revealed that although many testing results from studies

on nylon and acrylic fibers in carpets have been made

public, there are very few data available concerning the
behavior of polypropylene carpets. The existing informa-
tion about polypropylene as a carpet fiber is almost
exclusively that published by manufacturers of polypropy—
lene, especially as advertising material. The product
has won its great consumer acceptance by virtue of its
soil-resistant properties alone, and research is needed
in all phases of polypropylene carpeting to determine

its actual performance in use.

CHAPTER II
REVIEW OF LITERATURE

The first polypropylene carpets were introduced to
the consumer market in 1962. The needle felt process of
entangling fibers about a woven scrim of polypropylene
ribbon yarns was used. These carpets were sold for both
indoor and outdoor use and were especially advertised for
use in damp areas or those areas likely to be subjected
to frequent stains or spills. The low absorbency of poly-
propylene allows almost no penetration of moisture into
the fiber; therefore, it is not harmed by dampness, and
most stains and spills can easily be wiped off the fiber
surface. Polypropylene is a chemically inactive sub-
stance that is not damaged by most solvents, salts, acids
or alkalies.

Three years after the introduction of needle felt
polypropylene carpets, several companies began making
tufted polypropylene carpets. The backing material
through which the yarns were punched was usually jute,
although other substances were also used, including woven
strips of polypropylene, non-woven polypropylene fibers,

and non-woven glass fibers.

The manufacturers of isotactic polypropylene expected

the fiber to become rapidly established in many areas of

the textile market because of a number of properties

inherent

1.

in the fiber. These properties include:

High strength (h.5 - 7.0 g/denier tenacity, wet

 

or dry). (lh,p.l) High strength is important
in industrial and some apparel applications.

Low specific gravity (0.9 g/cc.). (lh,p.l)

 

With the lowest specific gravity of all natural
or man-made fibers, less polypropylene by weight
can be used to produce an equal bulk or cover.

Good abrasion resistance. Polypropylene is

 

superior to cotton, wool, rayon, acetate and
acrylic fibers in resistance to abrasion.
Superior chemical, mildew and rot resistance.
Polypropylene fiber is not attacked by mildew

or any other organism and is resistant to almost
all chemicals. This high resistance to deteri-
oration by organic materials is the most out-
standing feature of polypropylene. (l,p.6)

Low moisture absorbency. (0.1%) Since poly-

 

propylene absorbs very little moisture, it
allows very little of any staining substance to
penetrate the fibers. (l,p.H)

Lowgproduction cost. Polymerization of poly-

 

propylene is an inexpensive process, allowing

the prices of the fiber to be below the prices

of the competing fibers of nylon, acrylic and
polyesters. Polypropylene currently costs
$0.80 per pound, while nylon is $1.17, acrylic
is $1.13 and polyester is $1.15. (l9,pp.95-106)

Nonallergenic. Like all synthetic fibers, poly-

 

propylene is nonallergenic, giving it potential
use in hospitals and public buildings. (l,p.8)
Low rate of static build-up. (l,p.7) This is a

 

desirable feature, especially for carpets and
automobile upholstery material, since an annoy-
ing shock can result from friction followed by
touching metal if static build—up is high. Low
rate of static build-up is due to the low mois-

ture content of polypropylene fiber.

Polypropylene fibers have some characteristics

which are less desirable in textiles:

l.

Relatively low melting point. The melting

 

point is 3330 Fahrenheit, with a softening point
range from 3050 to 3150 Fahrenheit. These tem—
peratures are too low for some industrial appli-
cations. (lh,p.1)

Loss of tensile strength through oxidative

 

degradation caused by heat and light. This

 

property eliminates polypropylene from some
industrial uses and prevents outdoor use of

the fiber in tropical areas. (lh,p.110)

Early manufacturers of polypropylene saw tremendous
potential for this new fiber; however, low moisture absorb-
ency prevented dyestuffs from entering the fiber. The
failure to react with dyestuffs limited the new fiber
primarily to industrial products. Research was concen-
trated in finding a coloring method and nearly every known
dyeing technique was attempted. Early coloration had to
be done by solution dyeing techniques, and even this did
not allow a full color range. Later, experimentation with
fiber modification methods improved dye receptability and
the possible dye range, but the technique proved too
expensive for practical purposes. In 1963, yarn and piece
dyeing methods for polypropylene were discovered, whereby
the addition of residual metallic catalysts created dye
sites within the fiber. (13,p.3H) This discovery afforded
a possible dye range to allow the manufacture of a product
acceptable to the consumer as a carpet fiber. (6,p.36)

By mid-1965 dyeing methods improved sufficiently for the
fiber to be entered into the market in apparel and blan-
ket fabrics. (l2,p.180) Today polypropylene has found
its widest acceptance as a carpeting material and is
currently one of the three most competitive fibers in the
synthetic carpet industry, being outsold only by nylon
and acrylic fibers. (15,p.101) Other present uses of
polypropylene include socks, neckties, knit sport shirts,

sweaters, blankets, upholstery, patio furniture webbing,

place mats, grille cloth, rope and cording, feed bags,
bags for packing raw wool, and carpet backing material.
The tufting of broadloom carpets began after World
War II with the development of the wide tufting machine.
This construction process used needles to punch yarns
through a woven ground fabric to form loops on one side
of the fabric. These early tufted carpets were predomi-
nately made of cotton yarns tufted to nine and twelve
foot widths through cotton duck backing. These carpets
were generally inferior to woven carpets, the construc-
tion process used for most carpets at that time.
Tremendous growth has taken place in the tufting
industry since 1950, especially in tufted carpets. The
manufacturers of broadloom carpets began to tuft wool
carpet fibers through jute backing. This process pro-
duced a carpet superior to the cotton ones, although the
jute was sensitive to changes in humidity. This problem
was solved by the application of a secondary backing of
jute held in place with a latex adhesive. Next, as carpet
wool fibers became more expensive, the broadloom tufted
carpet industry began to use man-made and synthetic fibers,
using first rayon, then nylon, acrylic, modacrylic, poly—
propylene and now polyester fibers in both staple and
filament lengths. Other yarns, including acetate, metal-
lic and Saran, have been used in the manufacture of tufted

carpets but have proved unsatisfactory. (10,p.101)

10

A leading manufacturer of polypropylene presents a
comparison of the basic properties of polypropylene with
other major carpet fibers,acrylic,nylon, and wool. A
rating from "poor" to "exceptional" was given to several
carpet characteristics. Polypropylene was given a rating
of "exceptional" on abrasion resistance, stain and soil
resistance, and stain and soil removal. This fiber was
classified as being "excellent” in color retention, and
”very good - excellent" in texture retention. "Very good”
was the score given to resiliency, rate of electrostatic
buildup before and after shampooing, and "good - very
good" for pattern retention. (1,p.9)

Nevin and Mumford made an evaluation of the charac-
teristics of nylon, wool, acrylic and polypropylene as
carpet fibers for use in volume residential, luxury resi-
dential, and contract carpets. These authors stated that
"soil resistance is a noteworthy advantage of polypropy-
lene." This particular property is "currently precluded
by the durability and crush resistant properties which
limit the useful life of the carpet in even moderate
domestic use." (15,p.101)

Hercules Incorporated cites a test in which the
polypropylene carpeting produced in their plant proved to
be equal to nylon in abrasion resistance. After 700,000
revolutions in the Tetrapod Walker under conditions simu-

lating severe stair wear, the only signs of wear shown by

ll

polypropylene or nylon carpet samples were some broken
filaments. (1,p.3)
Thruslow writes, in reference to abrasion resist-
ance of polypropylene, that
wear resistance was so outstanding that in a normal
home the abrasion from walking and cleaning and gen-
eral use could be resisted for many years without
wearing through the carpet. However, on the edge
of stair treads a particularly severe type of wear is
encountered and it is important to know how the wear
resistance of this new polypropylene compares to
conventional carpet fibers for the stair tread type
of wear.
The stair wear test was conducted with a Taber Abraser
using CS-17 abrading wheels for 100 per cent nylon, wool,
viscose and polypropylene carpets. A rating scale was

set up basing resistance to wear on weight loss:

Weight Loss (milligrams) Classification
Per Thousand Cycles

0-200. . . . . . . . . . . . . Excellent
200-H50. . . . . . . . . . . . Good
M50-700. . . . . . . . . . . . Fair
Above 700. . . . . . . . . . . Poor

In this study nylon and polypropylene both rated as ”excel-
lent," wool rated as ”good,” and Viscose ranked as "poor."
(18,p.9t+)

Laughlin and Cusick conducted a study to determine
loss of weight and thickness in carpets after 50,000 revo-
lutions in the Tetrapod Walker. The samples selected were

of tufted nylon, wool, acrylic and polypropylene surface

l2

yarns with either cut or loop pile. The pile height was
constant for all samples but the pile weight was changed
by varying the number of tufts per square inch.

After the carpet specimens were run for 50,000
revolutions in the Tetrapod Walker, they were measured
for loss of weight and thickness. Those polypropylene
carpets tested revealed the same percentage of weight and
height loss whether the pile was cut or loop, while loop
pile lost less height and weight in all other carpet
fibers tested. It was found that for all carpet fibers
studied, an increase in pile weight resulted in a decrease
in the percentage of pile height lost. Laughlin and Cusick
did not try to make any judgments as to which fiber pro-
duced the best carpet, nor did they attempt to compare
the results of their study with probable results in floor
trials, since they did not use an underlay nor did they
add soil, which would increase the rate of carpet wear.
However, floor trials were conducted later using samples
from the same carpets that were used in the Tetrapod
Walker. The correlation coefficient for the floor trials
and the Tetrapod Walker tests was found to be 0.93, sig—
nificant at the 0.0001 level. It was concluded that the
Tetrapod Walker could be used to provide a quick, simul-
taneous and meaningful assessment of appearance retention

and thickness loss as related to actual performance in

use. (H,pp.HHH-HH5)

13

A study reported in the Journal of the Textile Insti—
.tutg gives the correlation coefficients for various abra-
sion machines. The correlation coefficients for the
Tetrapod Walker and the Taber Abraser were found to be
almost perfect (0.99 and 0.95, respectively). (20,pp.371-
372)

The studies cited above reveal a lack of agreement
as to the degree of abrasion resistance found in poly-
propylene carpet yarns. Both manufacturers of polypropy-
lene carpet yarns and independent research groups report
high abrasion resistance for polypropylene carpet yarns,
while one independent source made reference to the poor
abrasion resistance of the fiber.

Polypropylene is expected to find even greater uses
as a textile fiber in the future. At the present time
it is primarily used as a carpet fiber, but is gradually
working its way into other areas of the textile field,
including blankets and apparel. Polypropylene is an inex-
pensive fiber to produce and although it is now slightly
cheaper than other synthetic fibers, the cost of research,
especially dyestuff research, constitutes a large percent-
age of the retail price. Eventually, as the research costs
are reduced, the price of the fiber should be lowered,
resulting in a low-cost fiber with some good qualities for

textile products.

"1.

CHAPTER III
DEFINITIONS OF TERMS

A number of textile terms used in this study need

to be clarified. The definitions are as follows:

Abrasion Resistance is a "type of destruction resulting
from frictional forces on fabrics; rubbing away of
fabric by attrition which may occur as the result
of friction of cloth on cloth, cloth on external
objects, and friction of fibers on the dust or grit
in the fabric." (17,p.137)

Acrylic is a "manufactured fiber in which the fiber—forming
substance is any long-chain synthetic polymer com-
posed of at least 85% by weight of acrylonitrile
units (-CH2-gE-)." (8,p.22)

Carpet is a ”fabric for soft floor covering, especially
one used for the entire floor area and fastened to
it." (3,p.38)

Endpoint is that point at which the primary backing mate-
rial is first visible due to abrasion with the Taber
Abraser. (See Plate IV of Appendix.)

Isotactic is a regular form of polymerization retaining
the methyl side-chain on the same side of the back—

bone chain as follows:

1%

15

-gHCH2$HCH2gHCH2CHCH2............EHCH2-
H3 H3 H3 CH3 H3 (12,p.175)

.lppg is a ”fibrous skin forming the inner bark of an
Asiatic herb. Shredded and spun, it forms an inex-
pensive but strong and durable yarn used in carpet
backing to add strength and stiffness.” (3ap.39)

Multilevel Tuft Height is a tufted carpet construction of
high and low tufts producing an embossed pattern.
<3,p.27)

Nylpp is a "manufactured fiber in which the fiber-forming
substance is any long—chain synthetic polyamide
having recurring amide groups (-C-NH-) as an integral
part of the polymer chain." (8,p?23)

Polypropylene is a "manufactured fiber in which the fiber-
forming substance is any long-chain synthetic poly—
mer composed of at least 85% by weight of propylene
units.” (8,p.23)

Sample is each individual carpet used in the study.

Single Level Tuft Height is a tufted carpet construction
in which the tufts are all the same height.

Specimen is a piece of a carpet sample used for a single
test.

Standard Conditions are 70 degrees Fahrenheit (I 20) and
65 per cent Relative Humidity (i 2%). (2,p.l7)

Textural Effects are the structural characteristics and

fiber qualities which lend to the final appearance

and hand of the completed fabric. Structural

l6

characteristics include tuft height (single or
multilevel, long or short), tuft density, tuft type,
yarn diameter, yarn twist and fabric construction
method. (1,p.6)

Tuft Density is the number of tufts per square inch of
carpet material.

Tuft Height is the length of the tufts of a carpet.

Tuft Type is cut or uncut loops in a tufted or pile
fabric structure.

Tufting is "a process of manufacturing pile by means of
inserting loops into an already woven ground fab-
ric." (l2,p.289) This ground fabric is generally
closely woven from heavy yarns° Pile is formed by
drawing a yarn "from the face through the backing
and through the face again with long loops left
on the surface which may be cut or uncut." (5,
pp.110-111)

Egg; is the ”amount of deterioration of a fabric which
results from breaking, cutting or removal of fibers."
(l7,p-l36)

Yarn Twist is “the number of turns about its axis per unit

of length observed in a yarn.” (2,p.423)

CHAPTER IV
EXPERIMENTAL PROCEDURE
Selection of Carpets

The carpets selected for this study were single
level, tufted carpets of 100 per cent polypropylene sur-
face yarns. The yarns of two carpets were tufted through
a primary backing of woven 100 per cent jute fiber and the
yarns of the third carpet were tufted through a non-
woven 100 per cent polypropylene primary backing. All
three carpets had a secondary backing material of woven,
100 per cent jute applied with a latex adhesive. The
uncut loops of each carpet were made of 100 per cent poly-
propylene bulked continuous filament fiber that was
slightly twisted.

One of the carpets was obtained from a manufacturer
and the other two carpets were purchased at retail stores
in Lansing, Michigan. An attempt was made to hold tuft
density, tuft type (out or loop) and Yarn twist as con-
stant as possible while varying the tuft height. Neither
the carpet price nor the fiber or carpet manufacturer
was considered in the controlled variables. A medium

price range for single level polypropylene carpets was

17

18

selected; one carpet cost $5.95 per square yard and the

other two were $6.95 per square yard.
Preliminary Study

A preliminary study was conducted to standardize all
testing procedures. The carpet selected for the prelim-
inary procedure was made with 100 per cent polypropylene
surface yarns. The yarns were tufted through a primary
backing of 100 per cent jute and a secondary backing of
the same material applied with a latex adhesive. The
uncut loops were made of 100 per cent polypropylene bulked
continuous filament fiber with a slight twist and fifty-
six tufts per square inch (7 by 8).

The tests performed were done under standard con—
ditions of 65 per cent Relative Humidity (: 2%) and
included: verification of fiber content of the surface
yarns, yarn twist, thickness of the total carpet, thick—
ness of the backing material and pile yarns, pile weight,

backing weight, loop length, and abrasion resistance.
Laboratory Test Methods

1. Fiber Content Verification
a. Burning Test
Five surface yarns, each approximately ten inches
long, were removed from each carpet and held in
forceps over an evaporating dish. The results

were noted as the yarn was held close to a flame

19

of a bunsen burner, when the yarn was in the flame,
and after it was removed from the flame. The odor
and the residue were observed.

Microscopic Observation

Longitudinal View--Five yarns were taken from each

 

carpet. Each of the yarns was placed on a glass
microscopic slide and the fibers were separated
with a dissecting needle and covered with a glass
cover slip. Microscopic examination was made at
magnification powers of 10X and H3X.
Cross-Sectional View--Cross—sectioning of the
fibers was done with a hand microtome following
the procedure set forth in the ASTM Designation:
DlHHH-63, Standard Method of Test for Cross-
Sectional Characteristics of Cotton Fibers.
Cross-sections were made of five yarns from each
carpet and were placed on glass microscope slides
and covered with glass cover slips. Microscopic
examination was made at the powers of magnifica-
tion of 10X and 43X.

Solvent Test

Five surface yarns, each approximately one inch
long, were removed from different areas of each
carpet. Fifty milliliters of meta—Xylene were
poured into a beaker containing a carpet yarn.

The beaker was covered with a watch glass since

2.

2O

meta—Xylene is I flammable, and the solvent was

brought to a gentle boil for ten minutes.

Yarn Twist--Yarn twist was measured by using ASTM

designation: D1H23-62T, Tentative Method of Test
for Twist in Yarns (Direct-Counting Method). Ten
yarns ten inches long were carefully removed from
each carpet to prevent distorting the yarn through
stretching or in any other way altering the number
of twists per inch. Each yarn was mounted in the
clamps of the Suter Twist Tester and the twist

was completely removed by turning the rotating
clamp until the fibers were all parallel as deter—
mined by passing a straight pin between the fibers
from one clamp to the other. The direction of the
twist was noted. Each yarn was measured after the
twist was removed and the change in length was
recorded. The average twist per specimen was

calculated by using the formula:

total number of turns observed in the specimen
length of the specimen before untwisting

 

Average twist per sample was calculated by using

the formula:

sum of the calculated twist in all specimens
number of specimens

 

The per cent change in length during untwisting

was calculated for each sample as follows:

21

sum of per cent change in length in all specimens

 

number of specimens

The above procedure was followed but it was found
that the latex adhered to the yarn between each
tuft. A solvent was not found that would remove
the latex without damaging or distorting the
yarns. Each yarn in the three selected carpets
was made up of two colors of multifilament fibers
with all the fibers of one color being placed on
one side of the yarn and all the fibers of the
second color laid parallel to it on the other half
of the yarn before twisting. Because of this ar—
rangement of the colored fibers, it was possible
to make an approximation of the yarn twist. Taking
care not to alter the number of twists per inch,
each yarn was placed in the Suter Twist Tester as
described in the test method. By noting the posi-
tion of one of the two colors at one of the clamps
and counting how many times the fibers of that
color returned to the starting position between
the two clamps, an approximation Of the yarn twist
per ten inches of yarn was made. The formulas
given above were used to determine the average
twist per inch and the average twist per sample.
For each of the following laboratory tests the car-

pet samples were cut to the proper dimensions and then

placed in a conditioning room of 70 degrees Fahrenheit

22

and 65 per cent Relative Humidity for a minimum of #8
hours until a state of moisture equilibrium was reached.
The point of equilibrium was determined by weighing the
specimen on the analytical balance until the reading for
three weighings was constant to the nearest milligram.

3. Loop Length--It was found in the preliminary study
that the method provided by ASTquor determing loop
length was not adequate for this study. ASTM Desig-
nation: Dlh86-57T, Standard Methods of Testing
Tufted Pile Floor Coverings, suggests that twenty-
five yarns be removed from ten inches of each car-
pet, caution being taken to avoid stretching the
yarn. One end of the yarn is to be held at the zero
reading of a steel measuring tape graduated in centi-
meters and the other end of the yarn drawn until the
tension eliminates all the crimp produced by the
tufting process. The length is to be recorded to
the nearest 0.1 centimeter. The average of the
twenty-five readings for each carpet is to be taken
as the average length of yarn from a ten-inch speci—
men of carpet material. In order to determine the

length of a loop, the following formula was used:

average length of yarn ends
length of a carpet speCimen (10 inches)
number of tufts per inch of carpet material

 

This procedure was followed except for the method

by which the reading was taken. The point at which

23

the yarn was held under enough tension to lose all
its crimp was found to be too arbitrary. Since

the yarn was highly bulked, it could be drawn within
a range of several centimeters and still be con-
sidered straight. It was decided that if the yarn
was held at the zero point of the steel measuring
tape in a vertical position and a weight attached

to the other end of the yarn, the weight lowered
slowly and carefully to avoid stretching, a fairly
consistent reading could be made before the yarn
stretched under the weight. Several sizes of weights
were tested during the preliminary study and it was
found that the 100 gram weight was heavy enough to
straighten the yarn without applying undue tension.
Smaller weights did not remove the crimp of the
tufting process and larger weights put too much
stress on the yarn and tended to stretch it before

a reading could be made.

Total Carpet Thickness—-The total thickness of five

specimens five inches square taken from different
areas of each carpet was measured. The measurement
was made to the nearest 0.001 inch with the Schiefer
Compressometer under a pressure of 0.025 pounds per
square inch using a 3-inch circular presser foot.
Care was taken to avoid touching the area of the
specimen to be measured and to apply the pressure

slowly in order to avoid impact. A reading was

2%

taken after ten seconds. The average of the five
readings was taken to determine the average total
thickness of each carpet.

Back Thickness--The surface yarns were clipped from
five specimens five inches square taken from differ-
ent areas of each carpet. Each specimen was then
placed under a five-inch metal embroidery hoop and

a flame from a bunsen burner was directed to the
area inside the ring. The surface yarns remaining
after clipping were alternately charred and brushed
away without damaging the carpet backing. The
thickness of the backing material was measured with
the Schiefer Compressometer to the nearest 0.001
inch under a pressure of 0.025 pounds per square
inch, using a 1-inch circular presser foot. Care
was taken to avoid touching the area of the specimen
to be tested and to apply the pressure slowly in
order to avoid impact. A.reading was taken after
ten seconds. The average of the five readings was
taken to determine the average thickness of the back-
ing material for each carpet.

Net Pile Thickness--The thickness of the surface
yarns was the difference between the total carpet

thickness and the back thickness.

Weight-—All weight determinations were made according

to the ASTM Designation: D1H86-63, Standard Methods

of Testing Tufted Pile Floor Coverings. Linear

to

25

measurements were made to the nearest 0.1 centi-
meter, using a steel measuring tape.

Total Cgrpet Weight--Five specimens measuring ten
inches square were cut from different areas of each
carpet. Each carpet was weighed to the nearest 0.1
milligram. The average of the five weights recorded
was taken as an average weight of a ten-inch square
of carpet material for each carpet sample. Calcu-
lations were made to transform this weight into the
average weight of the total carpet per square yard.
Pile Yarn Weight--The surface yarns were clipped
from five specimens measuring ten inches square,

cut from different areas of each carpet sample. The
yarns were weighed on the analytical balance to the
nearest 0.1 milligram. The average of the sum of
the five weights recorded was taken as the average
weight of the surface yarns. Calculations were

made to convert this weight to the average weight

of the surface yarns per square yard.

Backing Weight--Five specimens measuring ten inches
square were cut from different areas of each carpet.
The surface yarns were removed by clipping and those
fragments of yarn which remained were removed by
charring and brushing the area within a metal ring
without damaging the backing material. The backing
material was weighed on the analytical balance to

the nearest 0.1 milligram. The average of the sum

26

of these five weights recorded was taken as the
average weight of the backing material.

Dissection Loss--The difference between the average
pile yarn weight and the average backing weight from
the total carpet weight is the fiber loss during
dissection. This weight was divided equally between
the weights of the surface yarns and the backing

material.

The above procedures were followed for determining
carpet weight; however, the results showed little
uniformity. While the original carpet specimens
were very similar in weight for each carpet sample,
there was a wide difference in weight for the speci—
mens of each carpet sample after the tufts were
removed. This happened because the tufts could not
be clipped evenly from the surface of the specimens
and very dissimilar readings were obtained.

6. Tuft Density--Tuft Density was determined by counting
the number of tufts in a 10—inch square of carpet
material and dividing this number by 100 to find
the number of tufts per square inch.

7. Abrasion Resistance--Abrasion resistance was deter-
mined according to ASTM Designation: D1175-61T,
Tentative Recommended Practices for Operating
Machines for Testing Abrasion Resistance of Textile

Fabrics, Section D, Rotary Platform, Double Head

27

Method. The instrument used was the Taber Abraser,
Research Model E-hOlO using H-l8 calibrade wheels
and the Taber Vacuum Pump, model E-HOO9.

Five specimens of each carpet sample were cut
into h-l/M inch circles, vacuumed lightly with
the vacuum instrument of the Taber Abraser to remove
any fibers or adhesive loosened by cutting the speci—
mens from the carpets and conditioned for a minimum
of #8 hours until standard conditions were reached.
The specimens were given numbers from 1 to 15, with
the specimens from the carpet with the lowest tuft
height being 1-5, the specimens of middle tuft
height being 6—10, and the specimens with the high-
est tuft height being ll-l5. A table of random
numbers was used to random order the specimens.
Each sample was then weighed, run to 50, 100, 300,
500, 750, 1000, 1500, 2000, 3000 cycles and to the
endpoint, with weighings being made at each of
these stopping points. The endpoint was determined
as that point at which the backing material was first
visible. During the testing procedure the vacuum
pump was started and the nozzle placed over the car-
pet specimen before the abraser was turned on. Care
was always taken that the abrasion wheels were
lowered gently onto the surface of the specimen in
order that fibers were not lost due to the initial

impact. The loose fibers which collected on the

“‘3

28

abrasion wheels were removed with a brush after 300,
500, 750, 1000, 1250, 1500, 1750, 2000, 2350, 2700,
3000 cycles and every 300 cycles to the end point.

The ASTM test method suggests that the lint be
brushed from the abrading wheels every 300 cycles
throughout the testing procedure in order that the
abrasiveness of the wheels not be decreased by lint
clinging to the surface. The researcher decided
that it would be likely that more fibers would be
lost during the first rotation of the abrading
wheels than during each individual cycle thereafter.
Therefore, it seemed more advantageous to stop the
abraser to clean the wheels at points closest to
every 300 cycles, where reweighing was to be done.
This prevented additional stops and starts and

the possibility of unnecessary weight loss.

Visual Appearance Changes-A subjective measurement was

used to note the change in visual appearance of a
specimen after various levels of cycles of abra-
sion with the Taber Abraser. A comparison was made
between the abraded carpet specimen and the original
carpet sample for changes in tuft type (broken fila-
ments), tuft height, yarn color and yarn texture.
Record was made of visual changes when they first
appeared and when they became intense. The measure
was made under the fluorescent lighting of the con-

ditioning room; no special lighting was used.

CHAPTER V
DISCUSSION OF TEST RESULTS

Laboratory testing of any textile material is likely
to reveal some inconsistencies due to the lack of uniform—
ity in fiber, yarn and fabric production. An insufficient
number of carpets was used in this study in order to make
generalizations about the abrasion resistance of tufted
polypropylene carpet yarns. The results of the laboratory
tests suggest some differences in the abrasion resistance
of carpets with varying tuft heights.

The fiber content was verified as polypropylene
through the burning test, microscopic examination, and
solvents. It was noted during the burning test that the
yarns shrank and fused as they were moved close to the
flame of a bunsen burner, curling away from the flame.
When the yarns were placed in the flame, they melted and
burned, giving off a black smoke and a chemical odor and
leaving a hard, black residue. The results are character-
istic of synthetic fibers.

Microscopic examination revealed the yarns to be

synthetic. The longitudinal view appeared round and

29

3O

smooth, with some delustering dots present. The cross-
section of the fibers was round.

The solvent used was boiling meta-Xylene, a solvent
for polypropylene. The yarns from all specimens were
completely dissolved.

The yarn twist for the yarns of each carpet was
found to be approximately 0.5 twists per inch. All yarns
were twisted in the "S" or right-hand direction.

The average length of yarn used to form a single
loop was 1.3662 centimeters for the carpet of low tuft
height, 1.7869 centimeters for the carpet of medium tuft
height and 1.9785 centimeters for the carpet of high tuft
height.

The standard thickness of each carpet was measured
with the Schiefer Compressometer to the nearest one—
thousandth inch under 0.025 pounds of pressure per square
inch with a three-inch presser foot. The tufts were
removed and the thickness of the backing material was
measured under similar conditions, except that a one-inch
presser foot was used. The results of this test are found
in Table l.

The thickness of the carpet referred to as ”HIGH”
gave a slightly lower thickness reading than the carpet
having medium tuft height, when measured with the Schiefer
Compressometer. Both visual observation and the loop
length test revealed a greater length of yarn per loop

for the carpet of high tuft height than for the carpets

31

of medium or low tuft heights. (See Appendix, Plates I
and II.) The tufts of the carpet with high tuft height
leaned to one side rather than standing upright as the
tufts of the other two samples did. This leaning resulted
in a lower reading with the Compressometer than was given
for the carpet of medium tuft height.
Table 1. Carpet thickness in one-thousandth inch units
under 0.025 pounds of pressure as measured with

the Schiefer Compressometer for three selected
tufted polypropylene carpets.

 

 

Tuft Height

 

 

LOW Medium High
Backing 151 152 1A3
Tufts 118 195 193
Total 269 3H7 336

 

The number of tufts per square inch, the tuft den-
sity, is recorded in Table 2. Tuft density is known to
have an important effect on abrasion resistance. (15,
p.101) An attempt was made to hold the number of tufts
per square inch as constant as possible.

The abrasion resistance at selected cycle levels
was determined by the weight loss in milligrams from the
original weight. The weight loss for the three carpets
at each selected abrasion cycle level was very similar
until the 3000 cycle level was reached. (See Table 3.)

At this point a significant difference, at the .05 level

32

of confidence, was found between the carpets of low and
high tuft heights. The carpet with low tuft height had
been abraded nearly to the endpoint when it had undergone
3000 cycles of abrasion, and consequently the tufts had
become very short. Any fibers broken off from this car—
pet somewhat before this point would be very short and
weigh very little. The fibers being broken from the other
two carpets as the 3000 cycle level of abrasion was
approached were longer, since the tuft height was con-
siderably higher and, therefore, weighed more than the
fibers lost from the carpet of low tuft height.

Table 2. Number of tufts per inch for three selected
tufted polypropylene carpets.

 

 

Tuft Height

 

 

Low Medium High
Length (t1)
(Direction of Tufting) 7.7 7.1 6.5
Width ' 8.1 7.8 8.0
Tufts per Square Inch
(t1 X t2) 62.37 55.38 52.00

 

The weight loss at the endpoint was found to be sig—
nificantly different at the .005 confidence level. At
3000 cycles of abrasion, the carpet of low tuft height
was only 258 cycles from the endpoint of 3258 cycles, so

the difference in weight loss between these two levels of

abrasion was slight.

tinued to withstand more than 1200 additional cycles

33

beyond the 3000 cycle level.

However, the other two carpets con-

The type of wear was slightly

different for the carpet with the longest tufts than it

was for the other two carpets.

The loops on this carpet

slanted to one side so that rather than breaking off the

part of the fibers on the top of a loop, the abrasion

wheels broke the part of the fiber on the side of a loop.

The wheels were rubbing along a larger area of a loop,

thus resulting in a greater total weight loss for the car-

pet with the longest loop length.

Table 3. Average cumulative weight 1053 in milligrams for
three selected tufted polypropylene carpets.

 

 

Number of Cycles

Tuft Height

 

 

of Abrasion Low Medium High
50 8.1 3.1 7.4

100 13.8 15.1 15.9
300 A8.A 38.2 57.2
500 82.9 69.8 95.0
750 133.0 110.H 150.8
1000 176.2 153.2 202.9
1500 253.7 231.0 289.7
2000 307.2 320.7 386.1
3000 AA7.9 A8o.6 55AL8
Endpoint 486.6 656.3 77H.9

(3258-A2u8)

 

3H

The number of cycles of the Taber Abraser required
to expose the backing material was found to be signifi-
cantly different at the .005 level for the carpets of low
and medium tuft height, and the low and high tuft height.
The loop lengths of the carpets of medium and high tuft
heights were sufficiently longer than the loop length of
the carpet of low tuft height to require approximately
30 per cent more abrasion cycles to wear these two carpets
to the endpoint. The number of cycles required to reveal
the primary backing on the carpets of medium and high tuft
height was almost exactly the same. Since the loops of
the carpet with highest tuft height were slanted, the
abrasion wheels struck the loops along the side instead
of wearing them down from the top. This caused the loops
to lose fibers near the base of the loop, resulting in an
earlier exposure of the backing material than would have
occurred if the loops had been upright.

Table 3 and Figure I show the weight loss at various
cycles of abrasion. Table H gives the analysis of vari-
ance tests which were done to determine whether or not
there was a significant difference between weight losses
for the three carpets at various intervals. Duncan's
Range Test (7,p.136) was performed on data which gave
significant results for the analysis of variance test,
and was done to show which of the carpets were signifi-

cantly different from one another at various cycles of

35

..Medium Tuft Height
---Low Tuft Height

——-——High Tuft Height

- N200

. 3000

L 2000

1500

I

_ lOOO

. 700
- 500
300

- 100

 

 

7000

6000 A

5000 _

000 A
000 1

a- (h
SWBJSIIIIW

2000 -

1000 -

600 A

200

Figure l.--Average cumulative weight loss in milligrams at
selected cycles of abrasion for three polypropylene

carpets.

36

Table 4. Analysis of variance at selected abrasion cycle
levels for three tufted polypropylene carpets.

 

 

Sums of Degrees of Squares of

 

 

Source Squares Freedom Means F
100 Cycles
Between 11.58 2 5.790
Within 204.34 12 17.028
Total 215.92 14 .340

1000 Cycles

Between 6207.30 2 3103.649
Within 12942.71 12 1078.559
Total 19150.01 14 2.87

33000 Cycles

 

Between 39844.93 2 19922.465
Within 55049.08 12 4587.423
Total 94894.01 14 4.3342*
88:28..
Cycles)
Between 209941.11 2 104970.554
Within 52895.38 12 4407.948
Total 262836.48 14 23.81***

Number of Cycles
to Endpoint

Between 2855429.20 2 l4277l4.600
Within 1586711.20 12 132225.930
Total 4442140.40 14 10.797***

 

*Significant at .05.
***Significant at .005.

37

abrasion. The findings of Duncan's Range Test are
reported in Table 5.
Table 5. Duncan's Range Test of significance at selected

abrasion cycle levels for three tufted polypro-
pylene carpets.

 

 

Weight Loss at 3000 Cycles

 

l 2 3 Value Required
447.9 MG 480.6 MG 554.8 MG for Significance

 

1 42.7MG 106.9MG* 95.00 (.05)
2 74.2 90.79 (.05)

Endpoint Weight Loss

 

1 2 3 Value Required
486.6 MG 656.3 MG 774.9 MG for Significance

 

1 169.7MG** 288.3*** 187.77( .001)
127.88(.001)
2 118.6* 91.23 (.05)

Number of Cycles to Endpoint

 

1 2 3
3258 4235 4248 Value Required
Cycles Cycles Cycles for Significance

 

1 977** 990** 731.13 (.01)
2 13 701.26 (.01)

 

*Significant at .05.
**Significant at .01.
***Significant at .001.

CHAPTER VI
CONCLUSIONS

In this study abrasion resistance was found to be
high for the selected tufted polypropylene carpets if
determined according to weight loss and very low if deter-
mined by visual observation. According to the classifica—
tion used by Thruslow (18,p.93), a carpet is rated as
having "excellent" abrasion resistance when the weight
loss is 0-200 milligrams after 1000 cycles of abrasion on
the Taber Abraser. Using this system, the selected poly-
propylene carpets were found to be highly resistant to
abrasion.

However, the appearance change after a very few
cycles of abrasion could be considered objectionable.
After fifty cycles of abrasion for all specimens
tested, wear had become apparent due to broken filaments,
stiffening of the fiber ends, and a whiteness at the end
of each broken filament caused by deterioration of the
dyestuff (see Appendix, Plate III). The path followed by
the abrasion wheels was noticeably depressed below the

surface of the unabraded parts of the specimen after

500 cycles of abrasion and the loss of color was very

38

39

objectionable by the time 300 cycles of abrasion had
been reached.

The statistical analysis shows that the amount of
abrasion required to wear the selected carpets to the
backing material is significantly different for the car-
pets with low and medium, and low and high tuft heights.
The researcher believes that although the carpets with
medium and high tuft heights were somewhat closer in
loop length than the carpets with low and medium tuft
heights, it is likely that the variation in height would
have been sufficient to show a significant difference in
abrasion resistance if the loops of the carpet with the
longest tuft height had been standing upright throughout
the testing rather than leaning to one side.

Although no generalizations can be made concerning
the abrasion resistance of tufted polypropylene carpets,
the three tufted polypropylene carpets selected for this
study must be considered as being low in abrasion resist-
ance. The average weight loss ranged from 153.2 milli—
grams to 202.9 milligrams at 1000 cycles of abrasion,
which would classify the carpets used as having excellent
resistance to abrasive action. (18,p.93) However, it
also must be taken into consideration that polypropylene
is the least dense of all fibers; therefore even though
the weight loss seems small, the actual volume of fiber
loss was rather large. The appearance of the carpets

even after a few cycles of abrasion was changed, due

40

to the breaking of filaments and the brittleness of
the fibers.

The height of tufts was found to be important in
determining the amount of abrasion required to expose the
primary backing material. The additional 0.6 centimeter
in the loop length of the carpet with medium tuft height
over the carpet with low tuft height was sufficient to
increase the abrasion resistance by approximately 30 per
cent in this study. Since textile fabrics are generally
used only as long as they retain their original appearance,
the researcher feels that these particular tufted polypro-
pylene carpets might have limitations in household use.

Several suggestions can be made for future testing
of the relationships between abrasion resistance and tuft
height in tufted carpets of 100 per cent polypropylene
surface yarns. First, more samples of additional tuft
heights need to be used to help locate the point at
which additional tuft height will make a significant dif—
ference in abrasion resistance. Second, methods need to
be improved for determining the weight of the pile and
the backing material and for determining loop length.
Third, the chance of multiplying any errors made in deter-
mining the weight 1035 to abrasion would be eliminated if
a new specimen were abraded to each of the levels of abra-
sion selected for weighing, rather than weighing a specimen
and continuing the abrading process until the next level

of abrasion was reached. A new scale for measuring weight

41

loss due to abrasion needs to be devised, in which the
density oftflxaparticular fiber content is taken into

account.

CHAPTER VII
SUMMARY

Three single level tufted carpets of 100 per cent
polypropylene surface yarns, each having a different tuft
height, were selected for this study. Other factors,
including tuft density, tuft type (cut or loop), and yarn
twist, were held as constant as possible. No attempt was
made to control the price of the carpet or the manufac—
turer of the fiber and/or carpet. The carpets selected
were obtained from a manufacturer and local retail stores
in Lansing, Michigan. The price of the carpets was within
the medium range for polypropylene carpets; one sold for
$5.95 per square yard and two for $6.95 per square yard.

All laboratory testing was done under standard con-
ditions using methods set forth in.A§TM. Preliminary
testing was performed prior to the beginning of this
study, using a fourth carpet to standardize all testing
procedures. The tests performed included fiber verifica—
tion, by burning, solvents and cross-sectional and longi-
tudinal microscopic observation; yarn twist; total carpet
weight, pile yarn weight and backing weight; loop length;

tuft density; and abrasion resistance. The specimens

42

43

were abraded with the Taber Abraser for 50, 100, 300, 500,
750, 1,000, 1,500, 2,000, and 3,000 cycles and the number
of cycles required to reveal the backing material. The
weight loss was determined at each of these ten levels of
abrasion.

The weight loss was found to be significantly dif-
ferent at the .05 level of confidence when an analysis of
variance was performed on the data. A .005 level of con-
fidence was found for the weight loss at the endpoint and
for the number of cycles required to reach the endpoint.
The Duncan's Range Test was applied to the data to deter—
mine which carpets were significantly different from the
others.

Although the study was too limited in scope to draw
any conclusions concerning the abrasion resistance of
tufted carpets of 100 per cent polypropylene surface yarns,
the three carpets selected for this study were considered
low in abrasion resistance, using change in visual appear-
ance as the criterion. Approximately 150 to 200 milligrams
of weight were lost at 1000 cycles of abrasion. This is
within the "excellent" weight loss range of a classifica-
tion set up by Thruslow; however, it does not take into
consideration the fact that polypropylene is the least
dense of all fibers and consequently, the amount of fiber
in 150-200 milligrams of polypropylene constitutes a fairly
large volume. The visual appearance of the carpets changed

markedly when the samples were subjected to very few cycles

m.

of abrasion. Even with fifty cycles of abrasion, the
carpets showed broken and brittle filaments. By 100
cycles, enough dyestuff had deteriorated to cause the
fiber ends to be white and the color change was very
objectionable after 300 cycles of abrasion. At the 500
cycle level, the path of the calibrade abrasive wheels
was worn below the surface of unabraded areas of each
specimen.

The difference between the loop length of the high
and low carpets and the high and medium carpets used in
this study was considered sufficient to reveal a signifi-
cant difference between the abrasion resistance of these
carpets. The high and medium tuft height carpets did not
show a significant difference in resistance to abrasion.
This is probably not only due to the fact that the car-
pets of medium and high tuft heights were closer in loop
length than those of medium and low tuft heights, but
also to the fact that the loops of the carpet of high
tuft height were leaning to one side and so received a
somewhat different type of wear than those carpets with

upstanding loops.

LITERATURE CITED

100

ll.

12.

LITERATURE CITED

Architect/Designer's Guide to Carpets of Herculon.
Wilmington, Delaware: Hercules Incorporated, 1966.

 

ASTM Standards on Textile Materialp. Philadelphia:
American Society for Testing Materials, 1965.

Carpets and Rugs. North Canton, Ohio: The Hoover

Company, 1966.

Cusick, G.E., and Laughlin, K.C. "Correlation Between
Floor Trials on Carpets and Thickness Loss Measure-
ment on the Tetrapod Walker Carpet Testing Machine,"
Jourpal of the Textile Institute, Vol. 58, No. 9,
September, 1967.

Dictionary of Textile Terms. Danville, Virginia: Dan
River Mills, Inc., 1967.

Eddington, Ellwood M. "Allied's New Dye for Polypropy-
lene," Modern Textiles Magazine, Vol. 44, No. ,
April, 1963.

Edwards, Allen L. Experimental Design in Psycho-
logical Research. New York: Holt, Rinehart and
Winston, 1965.

"Extract From Federal Trade Commission Rules and
Regulations Under the Textile Fibers Identification
Act," Man—Made Fiber Industry Fact Book. New York,

1967.

"Fiber Improvements Spark Continuing Boom in Carpets,"
Moggrn Textiles Magazine, Vol. 47, No. 2, February,
19 .

Hamilton, R.E. "Tufting Technology " Modern Teatiles
Magazine, Vol. 48, No. 5, May, 1967.

Hooper, Gilman S. "Polypropylene Textile Fibers,"
Textile Research Journal, Vol. 32, No. 7, July, 1962.

Joseph, Marjory L. Introductory Textile Science. New
York: Holt, Rinehart and Winston, Inc., 1966.

46

13.

l4.

l5.

16.

17.

18.

19.

20.

47

O'Donnell, William R. "Polypropylene and Its Uses,"
American Dyestuff Reporter, Vol. 54, December 6,

1965.

"Polypropylene," Textile Fibers Technigal Informa-
tion Bulletin No. PMF-l, Odenton, Maryland: The
Vectra Company, September, 1963.

Nevin, J.L., and Mumford, R.B. "Carpet Fiber Evalua-
tion," Textile Industries, Vol. 131, No. 2, Feb-
ruary, 1967.

Sieven 1per, FgL-g Dawson, R., Andrews, N.L., and
Strig t, P. 'Dyes for Polypropylene," Modern Tex-
tiles Magazine, Vol. 44, No. 1, January, 1963.

Skinkle, John H. Textile Testing. Brooklyn:
Chemical Publishing Company, Inc., 1949.

Thruslow N.A. "A Piece Dyeable Polypropylene Carpet
Fiber; Part II: Carpet Characteristics," Modern
Textiles Magazine, Vol. 44, No. 9, September, 1963.

U.S. Manmade Fiber Prices," Modern Texpiles Magazine,
Vol. 49, No. 3, March, 1968.

Weiner, Louis 1., and Pope, Clarence J. "Correlation
and Regression Analysis of Laboratory Abrasion
Testers," Textile Research Journal, Vol. 34, No. 4,
April, 196 .

 

APPENDIX

 

 

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