Netting Materials for Fishing Gear - Klust

8/10/2019 Netting Materials for Fishing Gear - Klust

1/193

FAO

Fishing

Manuals

Netting

materials

for

fishing gear

by

Gerhard

Klust

Published

by

arrangement

with

the

Food

and

Agriculture

Organization

of

the

United Nations

by

FUUftf

News

Books

14*

1

Lon*

Garden

Walk


2/193

FAO

1973,

1982

First

published

1973

Second

edition

1982

The

copyright

in

this

book

is

vested

in

the Food

and

Agriculture

Organization

of

the

United

Nations,

for which

Fishing

News Books

Ltd.

acts

as

publisher.

The

book

may

not

be

reproduced,

in

whole

or

in

part,

by

any

method

or

process,

without

written

permission

from

the

copyright

holder.

This

applies

in

particular

to

photocopying

of

the

designs. Appli-

cations

for

permission

to

engage

in

any

form

of

reproduction,

translation

or

degree

of

microfilming

or fair

copying

should

be

addressed

to:

The

Director,

Publications

Division,

Food

and

Agriculture Organization

of

the

United

Nations,

Via

delle

Terme

di

Caracalla,

00100

Rome,

Italy,

accompanied

by

a

detailed

explanation

of

the

purpose

and

extent of the

reproduction

desired.

British

Library

CIP

data

Klust,

Gerhard

Netting

materials for

fishing

gear.

2nd

ed.

(FAO

fishing

manuals)

1.

Fishing

nets

I. Title.

II. Series

639'.22'028

SH344.8.N4

ISBN

85238

118 2

Printed

in

England by

AdlardA Son

Limited,

Bartholomew

Press,

Dorking,

Suitoy


3/193

CONTENTS

page

1.

RAW

MATERIALS FOR

NETTING

1

1.1

Vegetable

fibres

1

1.1.1

Rotting

2

1.1.2

Preservation

against rotting

3

1.2

Synthetic

fibres

6

1

.2.1

Remarks

on

the

manufacture

6

1

.2.2

Chemical classification

10

1.2.3

Trade

names

12

1.2.4

Basic fibre

types

16

1.2.4.1

Continuous filaments

(multifilament yarn)

16

1.2.4.2

Staple

fibres

16

1.2.4.3

Monofilaments

17

1.2.4.4

Split

fibres

18

1.2.4.5

Use

for

netting yarns

18

1

.2.5 Main characteristics

of

synthetic

fibres

19

1.2.5.1

Endurance

in water

19

1.2.5.2

Resistance

to

weathering

20

1.2.5.3

Density

24

1.2.5.4

Melting

point

24

1.2.6

Identification

25

1.2.6.1

General

remarks

25

1.2.6.2

Water test

26

K2.6.3

Visual

inspection

2$

1.2.6.4

Burning

test

36

M6.5

Solubility

test

......

28

LZ6.6

Melting

point

test

...,,,^

,.

30


4/193

VI NETTING MATERIALS

FOR

FISHING

GEAR

2.

NETTING

YARNS

31

2.1

Construction

of

netting

yarn

31

2.1.1

Terms

and

definitions

31

2.1.1.1

Netting

yarn

31

2.1.1.2

Yarn

31

2.1.1.3

Single

yarn (55)

32

2.1.1.4

Netting

twine

or

folded

yarn

32

2.1.1.5

Cabled

netting

twine

or

cabled

yarn

32

2.1.1.6

Braided

netting

twine

32

2.1.1.7 Twist

32

2.1.1.8

The

direction

of

twist

32

2.1.1.9

Coefficient

of twist

or

twist

factor,

a 33

2.1.1.10

Braiding

33

2.1.1.11

Strand

33

2.1

.2 Construction

of

twisted

netting

yarn

33

2.1.2.1

Single

yarn

33

2.1.2.2

Netting

twine 34

2.1.2.3 Cabled

netting

twine

34

2.1.2.4 Cabled

netting

twine of

higher

order

35

2.1.2.5 Amount

of twist

40

2.1.3

Construction

of braided

netting

yarns

42

2.1.3.1

Core 42

2.1.3.2

Number

of

strands

44

2.1.3.3

Structure

of the

braid

45

2.1.4

Netting

yarn

from

knotless

netting

46

2.1.4.1

Japanese

twisted

netting

47

2.L4.2

Raschel

netting

48

2.1.4.3

Braided

netting

49

2.1.4.4

Properties pf

knotless

netting

49

2.2

Designation

of

netting

yarns

52

The

tex

system

53

Tex

system

for

netting yams

54

Complete

designation

54

2JLZ2

Brief

designation

,

55

2.13

Conventional

systems

and lex

system

56

International titre.

.

56


5/193

CONTENTS

VII

2.2.3.2 Metric

number

58

2.2.3.3

English

cotton

count

58

2.2.3.4

Runnage

58

2.3

Properties

of

netting

yarns

59

2.3.

1

Terms

and

definitions

60

2.3.1.1

Standard

atmosphere

60

2.3.1.2 Tensile test

60

2.3.1.3 Tensile

stress or

tensile

strength

60

2.3.1.4

Tenacity

60

2.3.1.5

Breaking

strength

or

breaking

load

61

2.3.1.6

SI

units

of

force

61

2.3.1.7 Knot

breaking

strength

61

2.3.1.8

Mesh

breaking

strength

61

2.3.1.9

Load

at

rupture

61

2.3.1.10

Breaking length

61

2.3.1.11

Nominal

gauge length

61

2.3.1.12

Pre-tension

62

2.3.1.13

Time-to-break

62

2.3.1.14

Extensibility

62

2.3.1.15

Elongation

(Extension)

62

2.3.1.16

Elongation percent

62

2.3.1.17

Elongation

at the

half

knot

breaking

strength

62

2.3.1.18

Load-elongation

curve

62

2.3.1.19

Tensile

hysteresis

curve

62

2.3.1.20

Elasticity

62

2.3.1.21

Toughness

63

2.3.1.22

Flexural stiffness

63

2.3.1.23

Abrasion resistance

63

2.3.1.24

Shrinkage

63

2.3.1.25

Knot

stability

63

2.3.2

Testing

of

netting

yarns

63

2.3.2.1

Breaking

strength

64

2.3.2.2

Elongation

66

2.3.2.3 Knot

stability

66

2.3.2.4

Change

of

length

in

water

68

2.3.2.5

Diameter

68

2.3.2.6

Flexural

stiffness

69

2.3.2.7

Abrasion

resistance

71

2.3.3

Breaking strength

and

knot

breaking

strength

of

netting

yarn

71

2.3.3.1

Fineness.

71

2.3.3.2

Breaking

strength

of

straight

netting

yarns

76


6/193

Vffl

NETTING

MATERIALS

FOR

FXSHINO

GEAR

2.3.3.3

Weaver's

knot

breaking

strength

81

2.3.3.4 Other

knots

85

2.3.4

Diameter,

Rtex,

and

knot

breaking

strength

88

2.3.4.1 Diameter

and

knot

breaking

strength

90

2.3.4.2

Wet

knot

breaking

strength

and Rtex

94

2.3.4.3

Diameter

and

mass

95

2.3.5

Flexural

stiffness

96

2.3.5.1

PA

single

monofilaments

96

2.3.5.2

PA

continuous

filament

netting yarns

96

2.3.5.3

PA

folded

monofilament

netting yams

97

2.3.5.4

PES

and

PP continuous

filament

netting yarns

99

2.3.5.5

PP

split

fibre and

PE

folded

monofilament

netting yarns

99

2.3.5.6

Vegetable

fibre

netting yarns

2.3.5.7

Stiffening agents

2.3.6

Change

in

length

in water

104

2.3.6.1

Netting

yarns

made of

PES,

PE

and

PP

105

2.3.6.2

PA continuous filament

netting yarns

105

2.3.6.3

Vegetable

fibre

netting

yarns

107

2.3.6.4

Change

of meshsize

in

water

107

2.3.7

Extensibility

HO

2.3.7.1

Elongation

at

half

knot

breaking

strength

112

2.3.7.2

Load-elongation

curves

112

2.3.7.3

Toughness

122

2.3.7.4

Elasticity

126

2.3.8

Abrasion

resistance

134

2.3.8.1 Criticism

of

testing

methods

135

2.3.8.2

Vegetable

fibre

netting

materials

137

23.8.3

Synthetic

netting

materials

137

2*3.8.4

Influence

of

treatment

and

construction

139

2.3.8.5

Roughening

of

netting

materials

139

3.

CHOICE

OF

NETTING

MATERIALS

FOR

FISHING

GEAR

142

&i

General

remarks

142

34

Specification

of

netting

yarn

and

netting

for

purchase

143

,.+*. -,...

,,..,, 144


7/193

CONTENTS

IX

3.2.1.1

Fibre

144

3.2.1.2

Size

144

3.2.

.3 Twisted

or

braided

netting yarn

145

3.2.

.4

Degree

of

twist

or

of

tightness

of

braid

145

3.2.

.5

Direction

of

final

twist

145

3.2.

.6

Core 145

3.2. .7

Weight

145

3.2.2

Netting

145

3.2.2.1

Knotted

or knotless

146

3.2.2.2

Size

of

mesh

147

3.2.2.3 Size

of

netting

147

3.2.2.4

Selvedges

147

3.2.2.5 Direction

of

stretching

148

3.2.2.6

After-treatment

148

3.2.2.7

Type

of

gear

148

3.3

Choice of

netting

material

for

bottom

trawlnets

148

3.3.1

High

breaking strength

149

3.3.2

High

extensibility

and

toughness

149

3.3.3

Small

diameter

150

3.3.4

High

abrasion

resistance

150

3.3.5

Polyamide

and

polyethylene

150

3.3.5.1

Arguments

in

favour

of

polyamide

150

3.3.5.2

Arguments

in

favour

of

polyethylene

150

3.3.6

Size

of

netting yarns

151

3.4

Choice of

netting

material

for midwater

trawlnets

155

3.4.1

Requirements

155

3.4.2

Kind and

size

of

netting

yarns

1

58

3.4.3

Hard

twisted

PA

netting

yarns

1

58

3.5

Choice

of

netting

material for

purse

seine

nets

161

3.5.1

Requirements

161

3.5.2

Kind and size

of

netting

yarns

161

3.6

Choice

of

netting

material

for

gillnets

162

3.6.1

Requirements

163

3.6.2

Kind

and

size

of

netting

yarns

163

3.6.2.1

Salman

gillnets

166

3.6.2.2

Cod

giilnets

1#5

3.6.13

Madcerel

gilteets

167


8/193

NETTING

MATERIALS

FOR

FISHING

GEAR

3.6.2.4

Gill

(drift)

nets

for

herring

and

sardine

167

3.6.2.5

Very

fine

giflnets

168

BIBLIOGRAPHIC REFERENCES 171


9/193

LIST

OF

FIGURES

page

FIGURE

1

.

Micro-photograph

of

cotton fibres from a

used

fishing

net 2

FIGURE

2.

Resistance

to rot of

cotton and

manila

netting yarns

5

FIGURE 3a.

Manufacturing

process

of PA

6.6

salt

8

FIGURE

3b.

Manufacturing process

of

PA

6.6 fibre

9

FIGURE

4.

Netting

yarns

of different

types

of

fibres

17

FIGURE

5.

Breaking

strength

of braided

trawl

twines

after

immersion

19

FIGURE

6.

Breaking strength

of

netting yarns

after

exposure

to

sun

22

FIGURE 7.

Device

for

melting point

determination

30

FIGURE

8.

Construction

of

twisted

netting

yarns

35

FIGURE

9.

Construction

of

a

complicated

netting

yarn

36

FIGURE

10.

Twist

counter

(or

twist

tester)

37

FIGURE

1

1

.

Braided

netting yarn

with core

and

8

strands

44

FIGURE

12.

16 strand

braid

for

heavy

trawls

45

FIGURE

1

3.

Most

common

constructions

of

braided

netting

yarns

...

46

FIGURE

14.

Braided

netting

yarns

of

different

construction

47

FIGURE

15.

Examples

for

constructing

bars

and

joints

of

knotless

48

netting

FIGURE

16.

Braided

knotless

netting

50

FIGURE 17.

Complete

designation

of

netting yarn

of

cabled

netting

twine

type

56

FIGURE 1

8.

Tensile

testing

machine

(electronic)

65

FIGURE

19. Two

forms

of

weaver's

knot

and

testing

arrangement

for

mesh

breaking

strength

66

FIGURE 20.

Possibility

for

testing

knot

stability

67

FIGURE

21.

Load-elongation

curve

of

slipping

weaver's knot

67

FIGURE

22.

Apparatus

for

measuring

length

of

netting

yarn

,

68

FIGURE

23*

Gauge

for

measuring

diameter

of

netting yarns

69

FIGURE

24.

Apparatus

far

measuring

flexural stiffness

of

netting

yarns

70

FIGURE

25,

Apparatus

for

testing

abrasion

resistance

72

FIGURE

26.

Types

of

knots

80


10/193

xn

NETTING

MATERIALS

FOR

FISHING

GEAR

FIGURE

27.

Direction

in

knotted

netting

81

FIGURE

28.

Relationship

between

breaking

strength dry,

straight

and

wet,

knotted

of

different

kinds of

netting

yarn

82

FIGURE

29.

Netting with

selvedge

of

thicker netting

yarn

84

FIGURE

30.

Single

and

double

weaver's

knots

87

FIGURE

3

la Most

common

sorts

of twisted

PA

continuous

filament

netting yarns

89

FIGURE 31fr

Twisted

PA

staple

fibre

netting

yarns

90

FIGURE

32.

Netting

samples

of

cotton

and PA

continuous

filament,

netting

yarns

of

equal

wet knot

breaking strength

91

FIGURE

33.

Netting yarns

of

equal

wet

knot

breaking strength

made

of PA and PE 92

FIGURE

34.

Relationship

between wet knot

breaking

strength

and

diameters

of

different

netting

yarns

93

FIGURE

35.

Relationship

between wet

knot

breaking

strength

and

Rtex of twisted

netting yarns

made of different

fibres

.

94

FIGURE 36.

Relationship

between Rtex

and

diameter of twisted

net-

ting

yarns

made

of

different

fibres

97

FIGURE 37.

Changes

in

mesh

size

due to

alternate

wetting

and

drying

of

finest

PA material

in

fine

gillnets

108

FIGURE 38.

Load-elongation

curves

of

twisted

netting

yarns (wet)

of

PA

continuous

filaments

113

FIGURE

39.

Load-elongation

curves

of

heavy

twisted

netting yarns

(wet)

of

PA

continuous

filaments

114

FIGURE

40.

Load-elongation

curves

of

netting yarns

(wet)

made of

PA

staple

fibre

115

FIGURE

41.

Load-elongation

curves

of twisted

netting

yarns

(wet)

made

of

PES continuous

filaments

116

FIGURE

42.

Load-elongation

curves

of

braided

netting yarns

(wet)

made of PES

continuous

filaments

116

FIGURE

43.

Load-elongation

curves

of twisted

netting

yarns

(wet)

made

of PE

folded

monofilaments

117

FIGURE

44.

Load-elongation

curves

of

twisted

netting yarns

(wet)

made

of

PP continuous

filaments

118

FIGURE

45.

Load-elongation

curves

of twisted

netting

yarns

made

of

PVAA

staple

fibres

119

FIGURE

46.

Load-elongation

curves

at low

loads

of

netting yarns

of

different

fineness

and

different

construction

120

FIGURE

47.

Load-elongation

curves

of PA

netting

yarns

in

dry

and

wet condition

123

FIGURE

48.

Load-elongation

curves

of

wet

netting yarns

made

of

different fibres

124

FIGURE

49.

Characteristic

examples

for the

toughness

of

wet

netting

yams

1

25

FIGURE

50.

Elasticity

of

netting

yarns

of different

kinds

of

fibres

I

tested

in

wet

condition

127


11/193

LIST

OF

FIGURES

XIII

FIGURE

51.

Elasticity

of

braided

PE

netting yarns

of

varied

make

. .

128

FIGURE 52.

Load-elongation

curves of

braided

PA

and PP

continuous

filament netting

yarns

(wet)

with

approximately

same

wet

knot

breaking

strength

and

construction

129

FIGURE

53.

Elasticity

of

dry

PA

and PP continuous

filament

netting

yarns

loaded

for

24

hours

with 30

percent

of their

breaking strength,

dry,

unknotted

130

FIGURE 54.

Knots

damaged

by

abrasion

135

FIGURE

55.

Netting yarns

of manila

and

PA

continuous

filaments

after

equal

frictions in

wet condition

136

FIGURE 56.

PA codline

of a

large

bottom

trawl

138

FIGURE 57. Section

of

a

river stow net

with

distorted

meshes

139

FIGURE 58. Section

of

the

codend

of

a

large

bottom trawl after

damage

in

propeller

140

FIGURE 59.

Designation

of size of

mesh

146

FIGURE 60. Influence

of

the level

of

twist

on

wet knot

breaking

strength

of

netting yarns

made

of PA continuous fila-

ments

159

FIGURE 61.

Load-elongation

curves

of

PA

netting

yarns showing

the

great

influence

of the level

of

twist

on

the

extensibility

160


12/193

PREFACE FOR THE

SECOND

EDITION

Since there

have

been

no

significant

technical

developments

in

synthetic

materials

for

fishing

nets,

for

this second

edition

of

the

FAO

Fishing

Manual

Netting

materials

for

fishing

gear

the

basic

contents

and

the

layout

of

the

first edition

(1973)

did not

need

to

be

changed.

There

are,

however,

a

fair

amount of

corrections,

modifications and

additions

in

order to

up-date

the

material

with

particular

regard

to

ISO

Standards

and

developments

in

terminology.

The

author,

therefore,

hopes

that this second edition

will

improve

the

usefulness

of this

Manual

for

fishermen

and

netmakers

in

the

selection

of

the

most

appropriate

kind

and

size

of

netting

materials

for the

various

fishing

gears.

The author

wishes

to

express

his

sincere

thanks to

Mr. P.

J.

G.

Carrothers

(St.

Andrews,

Canada),

Dr.

E.

Dahm

(Hamburg,

Germany)

and

Mr.

Russ

(Berlin,

Germany)

for their

advice,

as well as

to

the

staff concerned

of the

FAO

Fisheries

Technology

Service

for the

technical

editing

of

this second

edition.

G.

Klust


13/193

CHAPTER

1

RAW

MATERIALS

FOR

NETTING

According

to

the International

Organization

for

Standardization

(ISO),

netting

is

defined

as a

meshed

structure of

indefinite

shape

and

size,

com-

posed

of

one

yarn

or

of one

or

more

systems

of

yarns

interlaced or

joined

. .

. .

(54

in

bibliographical

references.)

The

raw

material

of

the

netting

consists

of

fibres

of

which

two

main

groups

may

be

distinguished:

natural

fibres and

man-made

fibres.

Of

the natural

fibres

for

fishing

nets

vegetable

fibres

are

utilized almost

exclusively

and

particularly

cotton,

manila,

sisal,

hemp,

linen

and

ramie.

Animal

fibres,

such

as

silk

or

hair,

are either not

suitable or

too

expensive

for

fishing

nets.

One

exceptional example

is

the

Japanese fishery

where

silk

nets

have been

used

for

specific

gear.

Of

the

man-made

fibres

only

the

category

of

the

synthetic

fibres

has

particular

advantages

for

fishing

nets.

Others such as

those

made

of

regenerated

cellulose

(rayon,

cellulose

wool)

are

not

superior

to

natural fibres and therefore

do not

need

to be considered. For

reasons

outlined below

synthetic

fibres

have

already

taken

over

almost

completely

in

progressive

fisheries

and natural

fibres

for

fishing

nets are

therefore

not

being

discussed

here

in

any

detail.

1.1

Vegetable

fibres

The

cotton fibres which

grow

on

the

seeds

of

the

cotton

plant

are

very

fine

with

a

length

of

only

20 to

50 mm and

a

diameter

of

about

0.01

to OXM

mm.

This

fineness

allows the

manufacture

of a

wide

range

of

netting

yarns

from

the finest

of

only

0.2

mm

diameter

such

as

is

required

for

very

light

gillnets

up

to

practically

any

size.

Consequently

also

many

other

types

of

fishing

gear

have been

made

of

cotton

netting

such

as various

seines,

small

trawls,

fyke

nets,

trap

nets,

lift

nets,

cast

nets,

trammel

nets.

In

the

past

cotton

was

the

most

important

fibre

for

fishing

nets.

The

hard

fibres

sisal

and

manila

or

abaca

are leaf

fibres

obtained

from

the

tissue

of

the

leaves

and

leaf

bases

of

an

agave

plant

(sisal)

or

of

the

fibre

banana

plant

respectively

(manila).

They

are

coarse

and

therefore

are

mainly

used

for

heavy

netting

as

is

needed

for

bottom

trawls

and

for

ropes.


14/193

NETTING

MATERIALS

FOR

FISHING

GEAR

Linen,

hemp

and

ramie

are

bast fibres derived

from

the

bast

tissues

of

the

stems. Twines made of these fibres were the material

of

special

nets,

for

instance,

linen

for

salmon

gillnets,

ramie

for

drift

nets

in

the

Asiatic fisheries

and

hemp

for

river

stownets or

trawlnets

in

Europe.

U.I.

ROTTING

Vegetable

fibres are

parts

of dead

plants

and

consist

mainly

of

cellulose.

Therefore,

when conditions

are humid or

when

they

are immersed

in

water

they

are attacked

by

cellulose

digesting

micro-organisms, especially

bacteria.

This

process

of

decomposition

of dead

organic

material

is of

vital

importance

for

maintaining

the life

cycle

because

it

releases

the

inorganic

nutrients

such

as

phosphorus,

nitrogen,

and

potassium

and

makes

them

available

for

new

plant

growth.

Thus

the

continuity

of

the

life

of

plants

and

animals

is

assured.

Unfortunately,

the

side effect

on

fishing

nets is a

source

of increased labour

and

financial

loss

and is the

main reason

for the advance

of

synthetic

fibres.

A

micro-photograph

of

cotton

fibres taken

from a

used

fishing

net

(Figure

1)

shows

the

damage

(corrosion)

caused

by

cellulose-decomposing

FIGURE

I.

Micro-photograph

of

cotton fibres

taken from

a used

fishing

net,

showing

corrosion

caused

by

micro-

organisms.

X

=

undamaged

fibres.

(For

better

visibility

of

the

damage

the

fibres

have

been

swollen

by

caustic

soda.)

bacteria.

There is

a

direct

relation

between the

number

of

corroded fibres

in

a

cotton

netting

yarn

and

its loss

in

breaking

strength

so that

determining

by

microscope

the

percentage

of

damaged

fibres is

an effective

means

for

judging

the

state

of

decomposition

and

the

remaining

usefulness

of

cotton

yarn

or

netting.


15/193

RAW

MATERIALS

FOR

NETTING

3

The

four

factors

mainly

determining

the

speed

of

decay

of

cellulose

fibres are:

kind

of

fibre,

water

temperature,

rotting

power

of

the

water,

duration

of

immersion

in

water.

The

resistance

of

the various

kinds

of

vegetable

fibre

against

rotting

differs,

and

increases

in

the

following

order:

linen,

hemp,

ramie, cotton, sisal,

manila

and coir.

However,

with

regard

to

practical

use

in

fishing

these

differences

hardly

count

at

all,

and

the

resistance to

rotting

of

all

(untreated)

vegetable

fibres

must

in

general

be

considered

as

not

adequate.

The

activity

of

the

cellulolytic

bacteria

depends

to

a

great

extent

on

the

water

temperature.

Consequently during

the cold

season

the

decay

of

vege-

table

fibres

is

considerably

slower

than

during

the

warm

season. In

the

tropics

nets become

useless

faster than

in

temperate

climates.

As

regards

the characteristics

of

the

water,

running

waters

generally

have

a

greater

decaying

power

than

stagnant

waters.

In

fertile

marine

or fresh

water

which

contains

a

high percentage

of

organic

substances,

lime and

phosphorous

(eutrophic

water)

and

consequently

has a

high

yield

of

fish,

unpreserved

nets

of

vegetable

fibres

are

more

quickly

destroyed

than in

unfertile,

clear

water.

For

instance,

in

the fertile

brackish

water

of

a North

Sea harbour

(Europe)

with

a

high rotting power,

cotton

netting yarns

decayed completely

within

seven

to

ten

days

during

summer

and

autumn at

15

to

20C

temperature,

and

heavier

manila

netting yarns

lost 75 to

85

percent

of

their

breaking

strength

within four weeks.

Fishing gear

left

uninterruptedly

in

water for

a

long

time is

naturally

more

liable to

rotting

than

when

used

only

temporarily,

and is

especially

liable to

rot

if

set

on

the bottom

where

the

contact

zone

between the

putrid

mud

and

the water

has

the

strongest

rotting power.

Rotting

is

stopped

only

when

nets

are

completely

dried out

even

to

the inside

of

the

knots.

1.1.2 PRESERVATION AGAINST ROTTING

The

search

for

means

to

increase the

resistance

against

rotting

is

probably

as

old

as the

use

of

vegetable

fibres

for

fishing

nets and

a

great

number

of

preservation

methods

have

been

developed

by

practical

fishermen,

by

fishery

research

institutes

or

the

chemical

and

textile

industries.

The

methods

of the

practical

fishermen

mostly

consist

of the

use

of

coaltar,

wood-tar

or carbo-

lineum,

either alone or

combined

with

petroleum,

benzene,

etc.,

or

in

the

treatment with

tanning

solutions

as catechu

( cutch ),

or

other

extracts

of

the bark or

wood

of certain trees.

The

use

of

metallic

compounds

such

as

potassium

bichromate,

copper

naphtenate,

copper

sulphate,

coprous

oxkfe

(e.g,

Tettalin )

were

introduced

by

research

institutes

tod

the

chemical

industries.


16/193

4

NETTING

MATERIALS FOR

FISHING GEAR

Of

the

variety

of

preservation

methods,

two

comparatively

highly

efficient

and

thoroughly

tested

combination

methods

deserve

attention : the

Testalin

preservation

and

the

preservation

by

tannin

plus

potassium

bichromate

(9a).

Testalin

method: The

nets

are

boiled for

30

minutes

in

a

solution

con-

taining

2

percent

of

a

tannin

agent

(e.g.

catechu

or

mangrove-extract)

with

an

addition

of

1

percent

of

the

coprous

oxide

agent

Testalin.

After

the nets

are

dried,

the

treatment

is

repeated,

adding

another

2

percent

of

the

tannin

agent

but

no

more

Testalin.

Additionally

the

nets,

while

still

wet,

may

be

dipped

in

carbolineum.

Tannin

plus potassium

bichromate

method:

The

nets

are

boiled for 30

minutes in a solution

containing

2

percent

of a

tannin

agent.

After

drying

they

are

put

for

one

hour

into

a

solution

containing

3

percent

of

potassium

bichromate

and

after

rinsing

in

water

they

are dried.

This

process

is

repeated,

adding

another

2

percent

of tannin

agent.

If,

in

addition,

the nets are

dipped

in

carbolineum

a three-bath-method

is

obtained

which is

one

of

the

best

net

preservation

methods known

in

fisheries.

The

preservation

effect

obtained

by

the

various

methods

depends

on

the

degree

of

the

cohesion

between

the

preserving

agent

and

the

fibres.

Tar

and

carbolineum,

even

if

deposited

in

a

thick

layer

on

the

surface

of

the

netting

yarn,

do

not

cling

tightly

round the individual

fibres

but

leave

gaps.

They

are

therefore

considerably

less

effective

than

the

two

methods

described

above,

by

which

the

surface

of each

fibre

is

completely

covered with

the

bactericide

preserving

agent,

which

also

penetrates

into

fibre-cuticles

and

cell-walls.

Furthermore

these

agents

are

also not

easily

removed

by

the water

and

therefore

provide

vegetable

fibre

nets

particularly

cotton with

a

comparatively

high degree

of

resistance to

decay.

Figure

2

demonstrates

how

many

times

the

usefulness of

netting yarns,

preserved

by

various

methods,

can

be

increased

as

compared

with

untreated

samples.

Nos.

6

and

7,

representing

the

methods

briefly

described

above,

rank

highest.

Simple

preservations,

e.g.

by

tar,

carbolineum or

tannin

alone

(Nos.

1

to

3)

are

quite

unsatisfactory

unless

they

are

repeated

frequently

at

short

intervals.

A

high

preserving

effect can

only

be

obtained

by

combining

the

treatments

with

tannin,

a

metallic

compound,

and

carbolineum

or

tar.

Of

the

metallic

compounds

tested

potassium

bichromate is the

best.

It

may

be

mentioned

that

most

preservations

offered

by

the chemical

industries,

which

consist

in

only

soaking

the

nets

in

special

solutions,

do not

improve

the

resistance

against

rotting

to

any

considerable

extent.

With

regard

to

the,

efficiency

of

net

preservation

against

rotting,

four

essential

reservations

should

be

made

;

t

Li

Even

the

best

preservation

can

only

retard

the

decomposition

of

vegetable

.

fibres

in

water

but

cannot

prevent

it.


17/193

RAW

MATERIALS

FOR

NETTING


18/193

NETTING MATERIALS

FOR

FISHING

GEAR

The

various

vegetable

fibres

react

differently

to

preservation.

As shown in

Figure

2,

a

high degree

of

protection

can

only

be obtained

for

cotton

but

not

for

hard

fibres

(manila)

and also

not for

hemp.

As

really

efficient

preservation

methods

require

a number

of

operations

and

costs

cannot be

neglected,

the

fishery

is

reluctant

to

accept

them

and

instead

uses

less

efficient

ones

usually

with

unsatisfactory

results.

The

preservation

of

fishing

nets

may

have side effects

on

the

physical

properties

of

the

netting,

such

as

stiffness,

flexibility, extensibility,

elasticity,

breaking strength,

mass,

colour,

shrinkage,

diameter,

which

have

to be considered

because

they may

be

disadvantageous

for

fishing

gear.

In

summing

up,

it

can be

stated

that

for

fishing

gear

vegetable

fibres

present

many

disadvantages,

the

most

important

of which

is

the

short

useful

lifetime.

Still,

for thousands

of

years,

fishermen

had

no choice

and had to

work with

gear

made

of material

which,

properly speaking,

is

not

really

suitable

for

this

purpose.

The fact that

the

introduction

of

synthetic

fibres

was one of the most

important

revolutions

in

modern

fishing

is

mainly

due to

one

predominant

characteristic:

they

do not

rot.

Furthermore,

no other

innovation

in

fishing

can be

as

widely applied

as

the

new net material.

It

is of

equally

great

advantage

to

large

scale

deep-sea

industrial fishing

as

it

is

to

the

small-scale

artisanal

fishery

and

one

can

only agree

with

the

words

of an

expert

that

synthetic

fibre

brings

to

one

of man's

oldest

occupations

the

miracle

of science

and,

in

doing

so,

provides

easier

living

for

the

fisherman.

1.2

Synthetic

fibres

Synthesis

is

the

scientific

and

technical

term

for a

chemical

process

by

which

chemical

elements

or

simple

basic substances are combined and built

up

to

complicated

and

completely

new

fabrics

with

new

properties.

Man-made

fibres

synthetically

made

of

such

simple

substances

as

phenol,

benzene,

acetylene,

prussic

acid,

chlorine

a.o.

are,

therefore

called

synthetic

fibres,

as

compared

with

other

artificial

fibres

made

of

complicated

natural

products

such

as

cellulose

and

protein

which have

only

to be

transformed into fibres

(cellulose

rayon,

cellulose

wool,

protein rayon).

1

2.

1

REMARKS

ON

THE MANUFACTURE

Hie

development

of

synthetic

fibres

was

started

around

1920

by investiga-

tions

of the

famous

chemist

H.

Staudinger

(winner

of

the

Nobel

Prize

for

chemistry

in

1

953).

fie

found

thai all fibrous

material

consists

of

long

chain

motecutes

in

which

a

great

number

of

equal simple

units

are

linked

together.


19/193

RAW

MATERIALS

FOR

NETTING

It

is this

very

structure

which

gives

the

fibrous

material

the

properties

re-

quired

from a textile

fibre.

Based

on

this

knowledge,

a

great

deal of

further

chemical

research

has been

carried out

in the

last

50

years,

at

first

in

the

USA

and

in

Germany,

to create

such

fibre-forming macromolecules,

a

term

much used

in

chemistry,

which

was

introduced

by

Staudinger.

At

present

the most

important

countries

manufacturing

man-made

fibres

are,

in

the

order

of

their

output:

USA,

Japan,

Federal

Republic

of

Germany,

USSR,

Great

Britain,

Italy

and

France.

It

is

neither

possible

nor

necessary

to

deal

very

intimately

with

the

very

complicated

methods

of

manufacturing

synthetic

fibres.

Only

the

most

important

steps

shall

be

mentioned,

without

entering

into

details.

For

this

purpose,

a schematic

and

simplified

outline for the

best known

synthetic

fibre,

nylon

(Figures

3a

and

3b)

may

serve

as

an

example.

First

step:

At

the

beginning

there

is a

simple

raw

material

originating

of

course

from

a natural

product

such

as

coal,

oil,

lime,

common

salt.

In

the

case

of

nylon

the

raw

material

is

phenol,

made

of coal

tar

(see

Figure

3a).

Second

step:

From

the

raw

material,

the basic

substances,

the

monomers,

needed

to

build

up

the

macro-molecules,

are obtained

by

a number

of

chemical

processes.

For

the

production

of

nylon,

two

basic substances

are

required:

adipic

acid

and

hexamethylenediamine,

which

are

combined

to the

PA salt

(see

Figure 3a).

Third

step:

The

next

important

manufacturing

process

is the

polymerization

or

polycondensation,

i.e.

the

forming

of

the

chain

of

macro-molecules

or

polymers.

This

process

mainly

consists

in

heating

in

an

autoclave

under

high

pressure

by

which,

in

the case

of

nylon,

a

great

number

of

hexamethylenediamine

and

adipic

acid molecules

are

alternatingly

joined

to

each

other

in

such

a

manner

that,

in the

end,

long

linear

polymers

are formed.

In

the

nylon

polymers

the two

components

are

linked

together

by

a

special

atomic

grouping

(NHCO)

which

is

known

as

an

amido

group.

For

this

reason

polymers

of

this

particular

type

are

called

polyamides.

The

polyamide

polymer

leaves

the autoclave

in

the

form

of

ribbons

which

are

cut

into

chips

(see

Figure

3b).

Fourth

step:

(See

Figure

3b)

The

substance

polyamide

(nylon)

most

now be

converted

into

fibre

form

by

melt

spinning.

For

this

purpose

the

polyamide chips

are

melted

and

threads

are

formed

by

squirting

the


20/193

NETTING

MATERIALS

FOR

FISHING

GEAR

water

coal

air

JflL

benzene

*

chlorine

chlorobenzene

phenol

hydrogen

cvclohexanol

cvclohexanone

+

nitric

acid

Qdjpic

acid

+

ammonia

adiponitriie

+

hydrogen

hexamethvlenediamine

coke

hydrogen

nitrogen

ammonia

hydroxylamine

nitric

acid

FROM

CHEMICAL

RAW

MATERIALS

TO POLYAMIDE &B

SALT

u

Mwurfacturmf

proccw

of

PA

6.6 wh.

Coo*

^ - ~

^TWo

the

bk

substance*

adipic

j

(schematized).


21/193

RAW

MATERIALS

FOR

NETTING

PA

6.6

salt

POLICONDENSATION

*

Finished

Polymer

PA

^>

cut

into

chips

-SPINNING

spinneret-*

cooling

air-*

DRAWING

FROM

PA

SALT

TO PA

NETTING

YARN

FIGURE

3b.

Manufacturing

process

of

PA

6,6

fibre.

Fnom

the

ttage

of

fonning

the

polymer

to

the final

product.


22/193

10

NETTING

MATERIALS

FOR

FISHING

GEAR

molten

substance

through spinnerets.

The

viscous

threads

become

stiff in

air,

but

they

are

not

yet

suitable

for

the

use

in

yarns.

They

are

still

extremely

ductile and

have a

comparatively

low

tensile

strength.

Fifth

step:

The

manufacturing

of filaments

is finished

by

drawing.

The

threads

are stretched

three

to five

times

their

original

length,

a

process

by

which

they

obtain

their final

fineness,

diameter,

tensile

strength

and

extensibility.

1.2.2 CHEMICAL CLASSIFICATION

The

following

chemical

groups

or

classes

of

synthetic

fibres are used

for

fishing

nets:

Polyamide

Symbol:

PA

Polyester

PES

Polyethylene

Polypropylene

Polyvinyl

chloride

Polyvinylidene

chloride

Polyvinyl

alcohol

PE

PP

PVC

PVD

PVAA

These

technical

terms indicate

the various

fibre-forming

substances

of

the

different

groups.

The

symbols

or

abbreviations

of

the

terms,

adopted

inter-

nationally,

should be

kept

in

mind because

they

are

frequently

used in

technical

literature and

also in

this

manual.

The

polyamide

(PA)

fibres

are

manufactured

in several

types

differing

in

their

chemical

components

and

also

in

some

properties,

e.g.

the

melting

point (see

Table

2c).

Each

type

is

marked

by

a

figure

which

is added

to the

generic

name

and

refers

to

the number

of carbon atoms

in

the

components

(monomers).

The most

important types

are

PA

6.6

and PA

6.

Polyamide

6.6,

the

manufacturing

of which

is

presented

in

Figures

3a

and

3b,

has

two

components,

hexamethylenediamine

and

adipic

acid,

each

containing

six

carbon

atoms.

The

fibre

was

developed

in

1935

by

W.H.

Carothers

(USA),

one of the most

eminent scientists

in

the

chemistry

of

macro-molecules,

and was

called

nylon.

Polyamide

6,

first

known

under the

trade

name

Perlon is

built

up

from

one

monomer

called

caprolactam,

which

contains

six

carbon

atoms,

and was

developed

in

1937/38

by

the

chemist

P. Schlack

(Germany).

At

present

there

are in the

world

more

producers

of

PA

6

than

of

PA 6.6.

Prom the fisheries

point

of view

there

is

no

difference

between these

two

PA

types

which

have

practically

the

same

mechanical

properties.

Netting

yarns

made

ofPA

6.6

or

PA

6,

when

manufactured

in

exactly

the

same

man-

ner,

wHl also

have

the same

suitability

for

fishing

nets.

Therefore,

when


23/193

RAW

MATERIALS

FOR

NETTING

1

1

discussing

the

properties

of

netting yarn

in

this

manual,

the

two

PA

types

are

not

distinguished.

The

polyester

(PES)

fibres

were

developed

by

J.R.

Whinfield and

J.T.

Dickson

(UK)

in

1940-41.

They

result

from

polycondensation

of

terephthalic

acid

and

the

alcohol

ethylene

glycol.

Chemical

compounds

of

an acid and

an

alcohol

are known

as

esters,

from

which

the

term

polyester

for

this

fibre

group

results.

The

first

trade mark

of

this

fibre

was

Terylene.

Polyethylene

(PE)

fibres,

which

are

used

for

fishing gear,

are

produced

by

a

method

developed by Ziegler

(Germany)

in

the

early

1950's.

Contrary

to

an

older

technique

of

polymerization

(UK),

which

required

very high

pressure

of

1000

atm

or

more,

the

newer

method

works

with low

pressure

and

organ

o-

metal

catalysts,

e.g.

aluminium

alkyl.

The fibres obtained

by

this

new method

have

greatly

improved

physical

properties.

The

monomer

ethylene,

the basic

substance

of

polyethylene,

is

normally

obtained

by

cracking

petroleum.

The

same

applies

to

propylene,

the basic substance

for

producing

polypropylene.

Polypropylene

(PP)

fibres,

which were

developed

in

1954

by

Natta

(Italy),

were

first known under

the trade name Meraklon.

Polyethylene

and

polypropylene

are

often

collectively

called

polyolefines.

Here

they

are

distinguished

as two

separate

groups

because

of

their

different

properties

with

regard

to

fishing

nets.

Polyvinyl

chloride,

(PVC)

developed

by

F.

Klatte

and H.

Hubert

(Ger-

many)

from

the

monomer

vinyl chloride,

was

the

first

synthetic

fibre

to

be

produced

on

an

industrial

scale

(1934).

It was

also

the first

synthetic

material

to

be

used

for

fishing

gear

under the

trade

name

PeCe,

and thus

the

first

to

demonstrate

the

immense

practical

advantages

of

rot-proofness (9a).

Polyvinylidene

chloride

(PVD),

developed

in

1939

in

the

USA,

is

produced

by

co-polymerizing

a

mixture

of

vinylidene

chloride

(at

least 80

per

cent)

and

a

second

component,

e.g.

vinyl

chloride.

In

this

composition

it

is

known

under

the

name Saran.

Another

group

of

chlorofibres obtained

by

co-polimeriza-

tion

is covered

by

the name

Vinyon

(USA).

Polyvinyl

alcohol

(PVA)

fibres,

the

production

of

which is based on

the

research

of

W.O.

Hermann

and

W.

Haehnel

(1931),

have

been

greatly

improved

in

Japan

since

1938.

The

type

of

PVA-fibre

made and

used for

fishing

nets

in

Japan

has been

made

insoluble

in

water

by

different levels of

acetalization and

now

has the

symbol

PVAA

(e.g.

Kuralon ).

The last

three, PVC,

PVD

and

PVAA

are

less

widely

spread

in

fisheries

over

the world

as

the other

groups.

They

are

mainly produced

and

used

for

fishing

nets

in

Japan.

The

above selection

is restricted

to

the

application

for

fishing

nets

and

does

not

cover

all chemical

groups

of

synthetic

fibres

produced

by

die

industry.

For

instance,

one

of

the

most

important

group

for

the

textile

industry,

the

polyacrylonitrile

fibre,

is

not

mentioned.

It

is

known,

among

others,

by

the trade

names

Acrilon

(USA,

UK,

Canada),

Casimtilon

(Japan,

South

Krnca),

Cresian

(USA),

Crytenka,

Nymcryion

(Netherlands),

Doha,

Braton,

Redon

(FR

of

Germany),

Exlan

(Japan),

LeacrH

(Italy).

Nitron

(USSR),

Often

(USA,

UK,

Canada,

Netherlands).


24/193

12

NETTING

MATERIALS

FOR FISHING GEAR

K2.3

TRADE

NAMES

The chemical

terms

for

the

various

groups

of

synthetic

fibres

are some-

what

complicated.

Furthermore,

producers

want

specific

trade

names

for

commercial

reasons.

Consequently

there

are not

only

one

or

a few

names

for

each

type

of

fibre

but

many,

which

vary

from

country

to

country

and

often

within a

country

from manufacturer to manufacturer. The

development

of

modern

extruders,

which

simplify

the

production

of

monofilaments and

fibrillating

films

from

PP

and

PE,

has

lead

to

an

increase

in number

of

manufacturers

and

thus further

contributed

to

the

somewhat

confusing

number

of

trade

names

for one and

the

same

product.

In

one

of the

most

extensive

publications

of

trade names

of man-made

fibres

for

the

whole

world

(28)

there are listed:

88

trade

names

for

polyamide

6.6

(PA)

186

,

,

,

polyamide

6

(PA)

100

78

136

46

19

24

polyester

(PES)

polyethylene

(PE)

polypropylene

(PP)

polyvinyl

chloride

(PVC)

polyvinylidene

chloride

(PVD)

polyvinyl

alcohol

(PVA

and

PVAA)

In

spite

of

this

large

number of

names

this

list

is

still not

complete

because

it

is

virtually impossible

to

keep

it

up

to

date.

Fortunately,

only

a

relatively

small

number

of

these trade

names is

used

and

needs

to

be

known in

the

fishing

industries.

A

selection

of

the

most

important

ones

for

fishing

nets

are

in

italics

in

the

lists

in

Table

1

which are

intended

to

enable

the

identifica-

tion

of the chemical

group

so

that

the

suitability

of

a

product

offered under

the

trade name

only

can better

be

judged.

Hie

selection of

trade

names

in

Table

1,

apart

from

the

products

of

the

large

industrial

countries,

especially

includes

the

products

of

countries

with

small

chemical

industries

which

may

he

of

interest

with

regard

to

price,

time

of

delivery,

etc.

In

general

this

list

does

not claim

to

be

comprehensive

and

certainiy

is not

meant

to

indicate

any

preferences.

Some

of

the

terms

are

no

longer

trade

names

only

but

have

become

generic

terms

for a

whole

group

of

fibres.

For

example,

nylon

is

applied

as

a

synonym

for

all

PA

fibres

(nylon

6.6

or

nylon

6);

Saran

is the

generic

'


25/193

RAW

MATERIALS

FOR NETTING 13

TABLE

1

TRADE

NAMES

OF SYNTHETIC FIBRES

Arg

=

Argentina;

Braz

=

Brazil;

Can

=

Canada;

CSSR

=

Czechoslovakia;

DDR

=

German

Democratic

Republic;

Den

=

Denmark;

Fra

=

France;

Germ

=

Federal

Republic

of

Germany;

GB

=

Great

Britain;

Ind

=

India;

It

=

Italy;

Jap

=

Japan;

Mex

=

Mexico;

Neth

=

Netherlands;

NZeal

=

New

Zealand;

Norw

=

Norway;

Pak

=

Pakistan;

Pol

=

Poland;

Port

=

Portugal;

Roum

=

Roumania;

SKor

=

South

Korea;

Swed

=

Sweden;

Swit

=

Switzerland;

Turk

=

Turkey; Yug

=

Yugoslavia.

Akulon

(Neth)

Amilan

(Jap)

Amilon

(CSSR)

Anzalon

(Neth)

Atlas-Draht

(Germ)

Atom

(Taiwan)

Ayrlyn (USA)

Bifil

(Neth)

Bodanyl

(Swit)

Caprolan

(USA)

Celon

(GB,

Fra,

Swed)

Century

nylon

(Ind)

Chemlon

(CSSR)

Chinlon

(China)

Cifalon

(Port)

Clion

(It)

Cordenkalon

(Neth)

Cuerda-Nylon

(Mex)

Cydsa-Nylon (Mex)

Dayan

(Spain)

Dederon

(DDR)

Delfion

(It)

Dimafil

(GB)

Duralon

(Mex)

Akvalon

(Norw)

Amyd

(USSR)

Anyd

(USSR)

Antron

(Arg)

Anzylon

(NZeal)

Blue

C

Nylon

(USA,

GB)

Brilon

(Arg)

Bri-Nylon

(GB)

Cedilla

(USA)

POLY

AMIDE 6

(PA

6)

Enkalan

(Neth)

Enkalon

(Neth,

GB)

Enzlon

(NZeal)

Fisisa

(Peru)

Forlion

(It)

Garnyl

(Ind)

Glamour

(Peru)

Helion

(Malta, It)

Hilon

(SKor)

Hirlon

(Arg)

Hsien-Chin

(Taiwan)

Jaykaylon

(Ind)

Julon,

Yulon

(Yug)

Kapron

(USSR)

Korlon

(SKor)

Lilion

(It)

Mirlon

(Swit)

Monosheer

(USA)

Nailonsix

(Braz)

Neva-Perlon

(Germ)

Nilom

(Pafc)

Nirlon

(Ind)

Nurel

(Spain)

Nycel

(Mex)

POLY

AMIDE 6.6

(PA 6.6)

Celfibras

(Braz)

Cordura

Nylon

(USA)

Ducilon

(Arg)

Herox

(USA)

Hisilon

(Arg)

Jayanka

(Ind)

Kenlon

(GB)

Knoxlock

(GB)

Luron

(GB)

Nylfil

(Mex)

Nylpak

(Pak)

Nytelle

(USA)

Ortalion

(It)

Perlon

(Germ)

Pescalon

(GB)

Platil

(6

+

6.6)

(Germ)

Platon

(Germ)

Polygal (Chile)

Prenylon (Arg)

Pylon (Pak)

Relon

(Roum)

Rulon

(Roum)

Seflon

(Turk)

Silon

(CSSR)

Sttton

(Pol)

Supralon

(Yug)

Teco-Polyamid

(Germ)

Tecron

(Spain)

Textilion

(Braz)

Turlon

(Turk)

Ulon

(Taiwan)

Unel

(Can)

Yuan

Bao

(Taiwan)

Neva-Nylon

(Germ)

Nylon

Poliafil

(USA)

Prenyl

(Arg)

Promilan

(Jap)

Roblon

(Den)

Synthyl

(Greece)

Amfi-Terfenka

(Neth)

Avlin

(USA)

Celtron

(Venezuela)

Dacron

(USA)

Delcron

(Mex)

Dicrolene

(Arg)

Diolen

(Germ)

Encron

(USA)

Bnkatene

(Neth)

Fortrcl

(USA)

GrisuteMDOR)

Hualon

(Taiwan)

POLYESTER

(PES)

Kalimer(lt)

Krafter-F

(Jap)

Lalelen

(Turk)

Lavsan

(USSR)

Nerlen

(Mex)

Polycron

(Peru,

Chite)

Quintess

Polyester

(USA)

Slotera

(CSSR)

Tergal (Fra)

Tcriber

(Spain)

Tcriprat,

Tcrprat

(Spain)

7Vr/r/(It)

Terlenka

(GB,

Neth)

Teron

(Roum)

Terylene (GB)

Tetoron

(Jap)

Torten(Pol)

Trevira

(Germ)

Vcnccron

(Venezuela)

Vestan(Germ)

Vitel

(USA)

Vycron

(USA)

Wellene

(USA)

dOO


26/193

14

NETTING

MATERIALS

FOR

FISHING

GEAR

TABLE

1

continued

Amco,

PE,

PP

(USA)

Amcostrap,

PE,

PP

(USA)

Akvaflex

(Norway)

Amerfil,

PE,

PP

(USA)

Argon

(Fra)

Bellex

(Jap)

Caralyan

(Jap)

Ccrfil

(Port)

Corfiplosle

(Port)

Courlene

(GB)

Dawbac, PE,

PP

(USA)

Diamond,

PE,

PP

(USA)

Drylene

3

(GB)

Etylon (Jap)

Fifmtex, PE,

PP

(Norw)

Filtrona,

PE,

PP

(GB)

Flotten

(Fra)

Fortiflex

(USA)

Gold

Metal, PE,

PP

(USA)

Hiralon

(Jap)

Hi-Zex

(Jap)

POLYETHYLENE

(PE)

Hostalen G

(Germ)

Hsien-Chin

(Taiwan)

Kanelight

(Jap)

Laveten,

PE,

PP

(Swed)

Levilene

(ft)

Marlin

(Iceland)

Monolene, PE,

PP

(Can)

Multilene,

PE,

PP

(Can)

Nex-M

(Jap)

Norfil

(GB)

Northylen (Germ)

Nymplex

(Neth)

Omni,PE,PP(Mex)

PCX,

PE,

PP

(GB,

USA)

Platilon

(Jap)

Polex

(Jap)

Polital,

PE,

PP

(Germ)

Politen-Omni

(Mex)

Poly-twine,

PE,

PP

(Can)

Polyex,

PE,

PP

(USA)

Poly-Net

(Germ)

Polytie,

PE,

PP

(Can)

Radiant

Twine,

PE,

PP

(USA)

Rigidex

(GB)

Rofil

(GB)

Sainthene

(Fra)

Scanflex,

PE,

PP

(Den)

Spiralok,

PE,

PP

(Can)

Sunline

(Jap)

Tanikalon

(Jap)

Teco-Polyathylen

(Germ)

Tiptolene,

PE,

PP

(Neth)

Trofil

(Germ)

Tuff-Lite-L

(USA)

Tufton,

PE,

PP

(Can)

Velon

LP

(USA)

Velon

PS

(USA)

Vestolen

A

(Germ)

Vislene

(It)

Wynene,

PE,

PP

(Can)

X-Crin

(It)

Akvaflex

PP

(Norw)

Beamctte

(USA)

Cotton

(GB)

Cournova

(GB)

Danaflex

(Den)

Drylene

6

(GB)

Duracore

(USA)

Ourcl

(USA)

Duron

(GB)

Fibrite

(GB)

Gcrlon(It)

Herculon

(US

A)

Hostalen PP

(Germ)

Labren(CSSR)

Marvess(USA)

POLYPROPYLENE

(PP)

(see

also

under

PE)

Merakrin

(It)

Monopro

(Can)

Movlon

(Port)

Multiflex

(Den)

Narco-Olefin

(USA)

Novolen

(Germ)

Nymplex

P

(Neth)

Olanc

(USA)

Patlon

(USA)

Polyclassis

(Germ)

Polyfitene

(Neth)

Polygrit

(USA)

Polyprop-Omni

(Mcx)

Polysplit

(Swed)

Pro-Fax

(USA)

Prolene

(Arg)

Propycell

(Can)

Pro-Zex

(Jap)

Red

Star

(GB)

Ribofil

(GB)

RR

(Den)

Tenite

(USA)

Three

Diamonds

Pylen

(Jap)

Tritor

(GB)

Trofil

P

(Germ)

Tuff-Lite-P

(USA)

Ulstron

(GB)

Velon

PP

(USA)

Vestolen

P

(Germ)

Viking (GB)

XP-Filaments

(USA)

Avi*coVinyon(USA)

POLYVWYL

CtOJORIDE


27/193

RAW

MATERIALS

FOR

NETTING 15

Clorene

(Fra)

Darvan

(USA)

Draka-Saran

(Neth)

Furlon

(Jap)

Kurehalon

(Jap)

TABLE

\

continued

POLYV1NYLIDENE

(PVD)

(Copolymer Fibres)

Omni-Saran

(Mex)

Saniro

(USSR)

Saran

(Jap,

USA)

Soviden

(USSR)

Spark-L-Ite-Saran

(USA)

Ssaniw

(USSR)

Tejido

(Arg)

Velon

(USA)

Cremona

(Jap)

Kancbian

(Jap)

Kuralon

(Jap)

Kuremona

(Jap)

Manryo

(Jap)

POLYV1NYL

ALCOHOL

(PVA(A))

(and

similar)

Mewlon

(Jap)

Titanol

(USSR)

Mikron

(SKor)

Trawlon

(Jap)

Mikulon

(SKor)

Vinylon

(Jap)

Niti-Vilon

(Jap)

Woolon

(Jap)

Many

trade

names

of

synthetic

fibres

are combined

trade

names,

com-

posed

of

the

generic

name

of

the fibre and the name

of

the

producer

or

coun-

try.

These are

not included in

Table

1.

Some

examples

are:

PA :

Asahi

Kasei

Nylon,

Bayer-Perlon,

Beaunit

Nylon

6,

Celanese

Nylon,

DuPont

Nylon,

Enka-Nylon,

Firestone-Nylon,

Nailon-Rhodiatoce,

Nylon-Fabelta,

Nylsuisse,

Toray

Nylon.

PES :

Enka-Polyester,

Kanebo-Polyester,

Teijin

Tetoron.

PE

:

Imperial

Polyolefine,

Industrial

Polyolefine.

PP

:

Chisso

Polypro,

Dawbarn

DLP,

Mitsubishi

Pylen,

Teyobo

Pylen, Wyomissing

Polypropylene.

PVD :

Asahi-Saran,

Bolta-Saran.

PVAA

Kurashiki

Vinylon,

Nichibo

Vinylon.

Another

category

of trade

names

which

must

be mentioned

refers to

combination

twines

for

fishing gears

which

consist of

two

different

synthetic

fibre

components

and

are

mainly produced

in

Japan.

Examples

are:

+

Saran

+

Saran

+

PVAA

staple

+

Saran

+

PVC

filament

+

Saran

+

PVAA

or PVC

staple

+

PVAA

staple

+

Saran

+

Saran

+

PVC

filament

+

PVC

filament

+

PVC

filament

+

Saran

+

PA

staple

+

PVC*tapie


28/193

16

NETTING

MATERIALS

FOR

FISHING GEAR

1.2.4

BASIC

FIBRE

TYPES

For

fishing

nets there is

now

a

wide

choice

of

textile

materials available.

In

addition

to

the

seven

synthetic

fibre

groups

providing

different

properties,

there

are within these

groups

various

types

or forms

of

fibres

which

again

provide

different

properties.

Most

synthetic

fibres

are

produced

in

several

of

the

following

basic forms:

continuous

filaments

(multifilaments),

staple

fibres,

monofilaments,

split

fibres,

cut

thin

monofilaments,

textured

continuous

filaments.

1

.2.4.

1

Continuous

filaments

(multifilament

yarn)

These

are

fibres

of

indefinite,

practically

infinite

length. They

have a

silk-like

appearance

and

are

produced

in different

degrees

of

fineness,

gen-

erally

much

thinner

than

0.05

mm

diameter. The

finest

types,

of

which

1,000

metres

have

a

weight

of

less

than

0.2

gram,

are

even thinner than

natural

silk.

Material

of

fishing

nets is

usually

made

of

filaments of which

1,000

metres

in

length

weigh

between

0.6

gram

and

2

grams.

A

quantity

of

continuous

filaments is

gathered up,

with

or without

twist,

to

form

a

filament

yarn,

in

ISO Standards

frequently

described

as multi-

filament.

These

yarns

are

smooth and

have a

high degree

of

lustre

unless

they

have

been treated

by

chemical

means.

All

filaments

run

the

whole

length

of

the

yarn

which,

at

any

point,

contains

exactly

the

same

number

of

filaments

in

the

cross-section.

Sample

(a)

in

Figure

4

shows

a

netting yarn

consisting

of

fine

filaments.

A

special

type

of

continuous

filaments are the

textured continuous

filaments

(multifilaments).

They

are

looped

and

tangled

before

twisting

and

have

a

good

knot

stability.

This

type

of

fibre is

not

usually

used

in

fishing

gear.

1.2.4.2

Staplefibres

These

are

discontinuous

fibres,

usually

prepared

by cutting

filaments into

lengths

suitable

for

the

yarn spinning

process.

Their

fineness is

similar

to

that

of

continuous

filaments,

their

length

generally

ranges

from

40mm

to

120mm,

or

more.

Staple

fibres

are bound

by

twisting

to form

a

spun yarn.

It

is

only by

the

pressure

caused

by

this

twisting

that

the

short

fibres

are

held

together

and

form

a

continuous

strand which

is

called

a

single

yarn.

In

this

regard

syn-

thetic

stapic

fibre

yarns

resemble

cotton

or

wool

yarns.

Netting

yarns

made

of

stapie

fibre have

a

rough

surface

owing

to

the

numerous

loose

ends of

fibres

stteking

out

from

the

twire.

This

hairy

nature

decreases

slippage

of

the

jJuM^s,

Spw

stapte

fibre

yarns

have

a

lower

tensile

strength

and

higher


29/193

RAW

MATERIALS

FOR

NETTING 17

extensibility

than continuous

filament

yarns

made of

the

same

kind

of

syn-

thetic

fibre material.

A

special

type

of

PP

staple

fibres

is

made from

PP monofilaments with

a

diameter

of

about

0.11

to

0.13mm

and

fibre

lengths

between

90cm

and

112

cm. Yarns

are

produced

on

bast or

hard

fibre

spinning

systems

(92a).

FIGURE 4.

Netting

yarns

composed

of

different

types

of

fibres

:

(a)

fine

filaments

;

(b)

monofilaments

(synthetic

wires); (cO

splitting

film

tape;

(c

2

)

split-fibres.

1.2.4.3

Monofilaments

The

term

monofilament,

in the

proper

sense,

means

a

single

filament

which

is

strong

enough

to

ftinction

alone

as

a

yarn

without

having

to

undergo

further

processing.

This

is

the

essential

difference

to

the fine

continuous

filaments

and

staple

fibres

described

above

which

cannot

directly

be

used

(as

individual

fibres)

for

netting. Especially

transparent

PA monoftlainents

are

used

as

single

filaments

for

fine

gillnets.

In

practice,

however,

the term

mono-

filament is

a

more

general

term

covering

all

coarse

filaments

with

larger


30/193

16

NETTING MATERIALS FOR

FISHING GEAR

diameter

and

stiffness

and

a

wiry

character

(synthetic

wires).

They

mostly

have

a

circular

cross-section

and

diameters between 0.1

and 1.0

mm

or

more,

but

monofilaments

with oval

or

flat

cross-section

are

also

manufactured,

i.e.

0.17

+

0.34

mm

or

0.24

+

0.48

mm.

A

number

of monofilaments

may

be

twisted

together

to form

a

yarn.

There

is

no

special

International Standard term

for

this

type

of

yarn.

Some-

times

they

are

described

as

folded monofilament

yarns

or

yarns

made

of

monofilaments.

Sample (b)

in

Figure

4

represents

a

netting

yarn

composed

of

monofilaments

with oval cross-section.

1.2.4.4

Split

fibres

Split fibres

which

have

been

developed

rather

recently,

originate

from

oriented

plastic

tapes (films)

which

are stretched

during

manufacture

by

such

a

high

draw-ratio

that

the

tapes split

longitudinally

when

twisted

under

tension.

Therefore,

a

yarn

made

of

these

fibrillating

tapes

contains

split

fibres

of

irregular

fineness

which,

in some

respects,

are

similar

to

natural

hard

or bast

fibres.

Sample

(cO

in

Figure

4

is such a

plastic

tape

which

already

shows

the

beginning

of

longitudinal

splitting. Sample

(c

2

)

represents

a

netting yarn

made

of

tapes

which

have

split

up

into fibres

during

the

twisting

process.

Split

fibres

may

also

be

obtained

by

mechanically

fibrillating

film

tapes

directly

after

Netting Materials for Fishing Gear - Klust

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