Flame retardant concentrates offer product and process benefits for compounders

E

Flame

retardant

concentrates

offer product

and process

benefits

for

compounders Product and process advantages can result from the use of flame retardant concentrates rather than raw flame retardant chemicals in the production of flame retardant compounds.According to Don Barber, business manager of leading North American flame retardant concentrate manufacturer Polymer Products Company, these include improved physical properties and product uniformity.While

in the compounding process, he argues that

benefits include improved housekeeping, reduced worker exposure, improved material handling and higher compounding rates. There (FR)

are a variety technologies

of flame retardant in commercial

use.

without overworking

the polymer. There

are two key steps, namely dispersion and

loadings ranging from approximately to over 90 weight per cent.

One of the most widely used is bromine-

distribution.

Carbon

based systems that employ an antimony

.

ders to deagglomerate.

oxide synergist

and one where concen-

trates are particularly FR concentrates converting

processes,

sheet extrusion, important

such as film and

they can be extremely

in compounding.

The compounder

dispersion

and thorough

useful. Although

are often used in other

Good

- deagglomeration

wetting of the powder

.

Good distribution

- spreading of the

wetted particles uniformly

through-

applications

that contain

that works. example,

In wire and cable

route

While

carbon

black

is the only one

this is an extreme

it illustrates the power of con-

centrates to improve dispersion.

out the polymer. To achieve good dispersion

faces a simple choice. A

black is one of the hardest pow-

the concentrate

particles by the polymer.

65

the applied

When

making

FR compounds

directly

shear must exceed the surface and elec-

from powders the dispersion

FR compound can be produced by feeding

trostatic

forces that hold the individual

bution steps have to be achieved simulta-

all of the ingredients, which are typically in

particles

together.

neously. By starting with a predispersed

This

is enhanced

powder form, along with the base polymer

applying

the shear when

to a compounding

viscosity

is high (colder

line. Alternatively pel-

by

the polymer melt).

A high

lets of concentrate can be co-fed having all

filler loading is also important

of the FR ingredients predispersed in the

centrates

resin matrix at the right ratios along with

the collisions

the base resin. This choice will have a sig-

gates. Solids loadings of 30 to 70 volume

nificant impact on the final product and

per cent have been

the compounding

process.

The goal of any compounding is to mix

the

Plastics Additives

ingredients

the power inpur and increases

effective New operation uniformly

& Compounding

April 2002

between

of

York:

Corporation., concentrate

powder

found

[Bernhardt,

Processing

Product properties

- it con-

E.

Thermoplastic Reinhold pp137,8]. this would

aggre-

to be most C.

1967.

Materials. Publishing

concentrate much

the distribution

easier. Good

achieved

through

and distri-

step becomes

distribution proper mixing,

a let-

down ratio no greater than 25 to 1 and a concentrate

viscosity that is a good match

with the let-down resin. Mixing is a simple task compared

to starting with pow-

ders. The concentration

of FR ingredients

in the final compound

almost always dic-

tate let-down

well below

ratios

In a typical FR

while concentrates

mean

need to match viscosities in mind.

a solids

can be

25: 1,

are designed with the

Flame There

are a number

concentrates

can improve product

erties. These ingredients. tribution

of ways in which

include

prop-

lower usage of FR

There is a more uniform of well-dispersed

FR ingredi-

ents along with the better control feed ratios,

which

dis-

of the

leads to lower usage

rates. Usage rates that are 95%

or even

retardant

are less free-flowing to bridge compared

to concentrate

lets. By using concentrates specialized equipment flame

Iiquids

retardant

chemicals

or low melting

materials

pose

solids.

problems

properly

achieved.

Lower

less

their

dilution of the base polymer so the prop-

form,

erties remain closer to the base polymer.

reduced

or eliminated.

Improved

Finally,

there are improved

aggtomerates

that can affect

and

properties.

surface

improved

control

fewer

toughness

In

addition,

of the FR ingredients

task.

and are difficult

in compounding

low viscosities. these

tion,

to mix

because are

rates

quality

simpler

are reduced.

compounding

of

it would

be normal

and

Contuct: Don G. Barber

pellets

control

of the con-

of FR ingredients

resulting in

Polymer Products Company, Inc. Chestnut Street, Philadelphia,

1314

tion leads to a more consistent product.

ed with air borne dust are also eliminated.

i%: + I 215 732 1965 xl 08

Well dispersed, ingredients

evenly

mean

more

good FR properties that are deficient is important

distributed

FR

When

the

persed

in a polymer

FR

ingredients

E-mail: dbarber@pmc-groupcorn

the com-

consistently

by avoiding

regions

in FR ingredients.

GET THE WHOLE STOREY ON STORFLAM FLAME RETARDANTS

This

in passing flame test stan-

dards, such as UL 94.

Compounding Starting

with the FR ingredients

persed in a carrier can significantly handling There

using concentrates of

material

improved worker

eliminated

include

and

reduced

Air borne

during unloading,

powder

Phosphates Esters. Aluminium Trlhydrate. Charmax AOM, MO and Inorganic Complexes. We can help improve your formulations

and solve your

problems.

is

Examples range from low smoke PVC wire and cable, PVC sheeting

conveying

and cleaning of feeding equipment. FR ingredients

Zinc Stannates.

process.

These

to Antimony Trioxide

The

and halogen-free

are often classified as nui-

rubber systems.

sance dusts and antimony

range

Antimony Trioxide.

in pellet form in terms

handling.

exposure.

form

of advantages when

housekeeping

a wide

of Inorganic Borates.

both material

and the compounding

are a number

Zinc Borates and

predis-

resin in pellet

improve

oxide powder

replacement

polymer and

Please call

poses special problems such as dermatitis,

Joseph Storey s COMPANY LIMITED

particularly in hot humid areas where an

Heron Chemcal Work,

individual perspires. In the form of a con-

Moor

Lane.

Lancaster LAI

IQQ

centrate normal material handling precau-

Tel: 01524

tions can be used and major investment in

Emad: pwallace@iosephsror~~.“k

dust collection equipment Improved metering

conveying

PA

USA

Fax: +I 215 732 3167

are predis-

carrier

while

extruders when starting with powders.

19107,

can also be improved.

equipment can use single

to use twin screw

Iess off-spec product. Yield losses associat-

properties

In addi-

screw extruders with concentrates,

and the improved dispersion and distribuFR

let down

are higher,

is lower, tempera-

can be used. Compounders

greatly

yields. Easy to meter concentrate centration

with over heating

In concentrate

problems

allow more accurate

is now a simple

Compounding

tures are lower and the issues associated

are These

in metering

physical properties can also be

to

and

power consumption

Improved

leads

Th e process

the need for

feeding can be avoided. Some

step is much easier. Power is no

longer required to disperse the powders.

pel-

for conveying

and feeding

dispersion

pounding

and have a tendency

90% of those with powders are possible. usage rates mean

concentrates

63252

Fax:01524381805

can be avoided.

Rc

and more accurate

can also be achieved.

Banner

Chemicals

Limited

Group

Powders RES

No. 015 - USE THE

FAST

NEW

ENQUIRY

SERVICE

Q www.addcomp.com

Plastics Additives & Compounding

April 2002

3