ISSN 2053-7174

September 2014

PICKING PIGMENTS FOR PLASTICS OPTIMISING EXTRUDER VENTING INNOVATIONS IN ANTIOXIDANTS TESTING MATERIAL PROPERTIES

Materials testing and analysis | new equipment

Materials-testing equipment and control software is more accurate and productive than ever, as well as easier to operate, writes Pat Toensmeier

Testing times for polymer properties Instron’s

Suppliers of materials-testing equipment continue to

a big impact on finished-product performance that

make advances in the accuracy, capabilities and

could result in an entire run being scrapped or sold as

ease-of-use of their systems. Compounders, as a

off-spec material.

result, have more options in selecting instruments that

AutoX750 extensometer

Recyclate isn’t the only concern. Major markets such

maintains

will help meet the ongoing challenges they face in

as automotive, aerospace, medical and packaging keep

accuracy of +/-1

materials analysis and related areas.

pushing the envelope when it comes to the development

micron over 750

Equipment suppliers cite several key concerns that

of enhanced polymer and composite formulations. The

compounders have when it comes to materials testing.

result is that compounders frequently deal with

Foremost is the ability to accurately gauge the charac-

advanced materials that need their composition and

teristics and performance of raw materials. This is

performance to be qualified before shipping. These

especially important with recyclate, which is rapidly

materials include the usual high-performance engi-

growing in use as an ingredient.

neering plastics, along with carbon-, glass- and

“We are seeing tremendous concern about recycled material,” says Kevin Menard, manager of thermal and elemental analysis at laboratory equipment and

natural-fibre reinforcements, and increasingly biobased plastics, all of which present testing challenges. “Automotive in particular is pushing for new

instrumentation specialist PerkinElmer. “For many

materials as OEMs seek to comply with different

years everyone talked about using recyclate in com-

standards,” says Richard Goshgarian, global plastics

pounds but it was not a big deal. Now it is, and com-

market manager at Instron, which supplies a number of

pounders want to be sure that what they order is what

testing systems. Most of these standards, whether in

they get.”

Europe, the US, or Asia, seek to reduce carbon emis-

The negative effects that bad recyclate has on a

sions and improve fuel mileage, which means vehicle lightweighting and compounds that replace metal in

sub-par recyclate with 80% virgin resin is going to have

applications.

▲

compound multiplies with its use. A 20% blend of

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mm of travel

September 2014 | COMPOUNDING WORLD

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new equipment | Materials testing and analysis

Auto OEMs are also handing over testing responsibilities to compounders to save money and reduce the time it takes to certify materials. One outcome is that

The AX750 tests all plastics, composites and elastomers. The ability of operators to adjust clamping

suppliers to acquire support for sophisticated tests on

force, use interchangeable knife edges, and its virtually

complex formulations.

weightless arms allow the instrument to be tailored for

“Our customers want to partner with an instrument

different materials. The gripping system is spring adjusted and can be

applications,” says Stephanie Blaha, senior account

set to clamp a specimen without digging into the

representative for plastics at Arizona Instrument,

material. This reduces stress on the sample, making

which specializes in moisture analysis equipment. “Any

test data more accurate, Goshgarian says.

moisture analysis method will give you a number, but

The device has automatic gauge-length positioning

when you’re working with a complex compound on a

and attachment of specimens in place of manual

deadline, you want to be confident you’re getting the

operations. The measuring arms are counterbalanced

right one.”

and motor-driven along a low-friction linear guidance

There is additionally the issue of user-friendly

software shows

materials.”

more compounders are working closely with equipment

manufacturer that helps them through challenging

Instron’s DIC

product to accommodate many different types of

system. This makes them almost weightless, Instron

equipment. The expertise of personnel within many

maintains, and assures they will not affect sample

compounding plants is changing, and not always for the

properties. The advantages, the company reports, are

better. “More compounders no longer have the luxury of

simplified test routines, repeatability and high through-

a plant chemist,” says Menard.

put.

“We’ve noticed a trend in labs where more operators

The AX750 works with Instron’s Bluehill 3 software,

full-field strain

with less materials-testing experience are operating

and runs with manual or automated systems. Calcula-

and displace-

machines,” notes Goshgarian. “This makes ease-of-use

tions include modulus data, offset yield, and non-pro-

ment images of

a critical requirement for us.”

portional elongation to failure.

a sample’s surface

Suppliers cite many reasons for this, among them:

(DIC) software with its Advanced Video Extensometer.

as older workers retire; downsizing by companies; and

DIC generates full-field strain and displacement

a tendency to assign testing duties to recent hires with

images of a specimen’s surface during testing. For

little experience.

materials that don’t have unique surface patterns,

Whatever the cause, the result is the same: com-

Shimadzu’s DSES-1000 extensometer can be used

such as universal testers

data. The software can then compare the many

equipment that can be successfully operated

patterned points on the speckled surface to visualize

by almost anyone.

strain rates and displacement over the sample.

On the following pages we examine

The product is called DIC Replay Software.

some recently developed examples of

Rather than getting data from a conven-

testing equipment that address many of

tional extensometer test that focuses on

these needs.

two points, operators see how all the speckled points behave during testing. The

Mechanical testing

DIC software indicates such conditions as

Instron recently added two models to its

discontinuous yielding, identifies cracks

product range. One is the AutoX750

that are not visually apparent, and detects

(AX750) Automatic Contacting Extensom-

localized strains, among other results.

eter, which features automatic setup, long

Buying a non-integrated, third-party DIC

travel, high accuracy and an adjustable

system can be expensive, and it typically

gripping system for hard and soft

requires experienced operators to run,

materials.

claims the company. Instron’s DIC replay

Goshgarian says the AX750 has 750

offering is integrated and has a simple

mm of travel, and accuracy of +/-1 micron

interface, Goshgarian says. “Labs with our

across that distance. “There are other

existing video extensometers have the

devices with reasonable travel, but few have both travel and accuracy,” he states. “Having the combination of high travel

compounding world | September 2014

option of purchasing the DIC replay software, which requires no additional hardware. Labs without current systems can

s

and high accuracy is what enables this 62

applying a speckle pattern is necessary for accurate

pounders need simple, yet accurate and repeatable

with other instruments

Instron has also integrated digital image correlation

high turnover rates; the loss of institutional knowledge

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new equipment | Materials testing and analysis

purchase both the Advanced Video Extensometer and

vital. Among instruments that PerkinElmer supplies for

DIC replay software.”

this task are its DSC (differential scanning calorimeter)

Another supplier of extensometers with long travel

the Model 8500. This double-furnace device (one

its range is the DSES-1000, which has maximum travel

furnace is for sample material and one for reference

of 1,000 mm, and is designed for elastomers and other

material) boasts rapid heat-up and cool-down rates –

soft materials.

up to 750°C/min, says Menard. Most conventional

Gilbert Vial, Shimadzu’s product manager for testing equipment, says that the company continually improves the accuracy of devices by upgrading the electronics.

heating and cooling scans operate at 10 to 20°C/min, he adds, which extends testing time. Thermal analysis allows compounders to determine

The DSES-1000 achieves relative elongation measure-

the exact composition of polymers more accurately than

ment precision of +/-0.2% (or 100 microns, whichever is

with infrared (IR) spectroscopy and other techniques,

greater) over a displacement range of 50 to 1,000 mm.

Menard claims. With recyclate, for example, the DSC

The unit measures elongations of up to 4,000% on

8500 reveals the full chemical composition, including

gauge lengths as small as 10 mm, and 1,000% on

additives, of co-mingled scrap. He explains that when

lengths of 40 mm. The device has a lateral quick-

using IR spectroscopy, a high-molecular-weight

clamping mechanism that simplifies centring of

polyethylene (PE) looks similar to polypropylene. “There

samples. The DSES-1000 runs the company’s Trape-

are some differences, but nothing I would want to make

zium X and Trapezium Lite X testing software.

a call on,” says Menard.

The extensometer can be used with other Shimadzu

In evaluating a mixed stream of PE grades, the DSC

instruments for strength evaluations, among them the

8500 rapidly reveals the density or molecular weight of

AG-X and AGS-X Autograph Series of precision

each type – linear-low-density, low-density, medium-

universal testers.

density, and higher. As densities increase, so do the

Two developments targeted at automotive, aero-

melt points of each PE type. It is this basic relationship

space, and other industries are the Hydroshot HITS-T10

that forms the basis of the data that allow technicians

high-speed tensile-testing machine and HITS-P10

to identify polymer types, even in recyclate.

high-speed puncture impact-testing machine. Both generate dynamic testing data. The T-10 plots stress-strain curves, The Hydroshot

product range, which has recently been extended with

and high precision is Shimadzu. One recent addition to

Notable features of the DSC 8500 include data-readout rates of 100 points/sec, which reportedly improve data integrity, and a “ballistic cooling function” that

maximum test force, energy, displace-

achieves an instantaneous cooling rate of 2,100°C/min,

ment, and other data via impact testing at

by shutting off power to both furnaces.

HITS-T10

up to 20 metres/sec (65.6 ft/sec), with an

The issue of the integrity of recyclate led PerkinElm-

high-speed

impact force of 10 kN. The impact comes

er to develop the FTIR Polymer Resource Pack software

from a piston that travels 300 mm. The

for use with its Spectrum Two IR and Frontier spectros-

objective is to generate strength data

copy systems. The Resource Pack is an addition to the

that verifies material selection or

software used by these systems and is designed to

enhances product design.

improve the measurement and interpretation of

tensile tester from Shimadzu generates dynamic test data

The HITS P-10 also uses a piston to measure impactfracture properties, which

pol-

ymer spectra, and thus identification. PerkinElmer is among suppliers that offer hyphenated

are vital to specifying plastics

systems: two instruments

and maintaining quality during

representing different analysis

compounding. The piston stroke

technologies coupled together

is adjustable to 300 mm, and

to achieve results that

the speed range is 1 to 20

wouldn’t be possible

metres/sec. An optional

from either device

thermostatic chamber

alone. One system Menard

permits settings of -40 to

cites links a thermo-

150°C.

gravimetric analyzer to an evolved gas analysis

Analysing recyclate Accurate analysis of raw materials and compounds is 64

compounding world | September 2014

system, for a process called TG-IR Hyphenation. Compounders use this to analyze off-gassing in recycled materiwww.compoundingworld.com

Materials testing and analysis | new equipment

als, which in reclaimed packaging could be caused by trace particles of former contents. “This would be used if there were concern about residue leeching off recycled polymer into a compound,” he explains.

Automatic choices One way to speed testing and eliminate human factors that affect results, such as improper sample placement or even the effect of hand temperature on specimens, is to automate the process. Zwick Roell is one of the companies that supply robotic systems for test equipment. The company’s RoboTest R robotic system places each specimen it selects from a pre-loaded magazine in the testing device accurately, then extracts and places it in a separate container. The extensometer operates automatically and records data for trending, reports, and other uses. Apart from the inherent accuracy of automation, the system can improve productivity and reduce testing costs. “The automated feeding system is important for compounders

The Zwick Roell RoboTest R automated testing system eliminates human errors that affect data

new equipment | Materials testing and analysis

a different drying characteristic, and thus entails changing test parameters for accurate readings. Arizona Instrument wants to simplify moisture analysis with the Computrac Vapor Pro, which uses a relative humidity sensor to gauge the moisture content of a polymer or compound. “It is easy to use, requires no toxic reagents, and is supported by ASTM D7191-10,” Blaha says. “For most compounding applications, Vapor Pro is faster than an oven and more accurate than loss-on-drying instruments.” The device uses samples as light as 0.25 grams. It is effective with almost any compound, including some incorporating materials that are problematic with other moisture-analysis methods, such as polyamides and colorants.

Upgrading melt indexing The Zwick Roell

that have fewer personnel in their labs,” says Florian

A common test instrument in many labs is the melt

RoboTest R’s

Liebert, industry manager for plastics and composites

indexer. Tinius Olsen recently added the Model MP1200,

robot arm

at Zwick USA.

an upgrade from its MP600 series. Expanded features

selects a

Setup of the RoboTest R cell is simple. An operator

include advanced statistical process control (SPC) and

specimen from

fills a magazine, which holds up to 400 specimens

a magazine of

depending on their size and dimensions. Each speci-

samples

men can have a barcode with data for pre-test scan-

the plunger weights that push melt through the die

ning, or data is entered on the PC that stores test

opening, or as a motorized weight-activation version.

results. The robot runs on Zwick Roell’s TestXpert

The weights are stainless steel and tapered to facilitate

testing software and AutoEdition2 automation software.

loading and unloading, and the unit has a simple

The cell’s modular configuration means multiple test

die-release for fast unloading and cleaning. Extrudate

instruments can be added. Manual operation is initiated

can be cut manually or with an electric device.

by moving the robot arm to a “park” position, which

greater data storage and reporting. The MP1200 comes with either manual application of

The MP1200 has a three-zone heater – one more

gives an operator access to the test equipment and

heater than on many indexers – to increase tempera-

specimens.

ture stability. The device operates at a maximum 450°C,

The automated cell operates 24/7, and the robotic test system components are described as virtually

and is controllable to +/-0.1°C along the barrel. A feature of the model is a 7.1-inch LCD touchscreen

maintenance-free. Costs depend on various factors, but

with menu-driven displays. Using these, an operator

Zwick Roell estimates that return on investment is

can rapidly set the unit up for testing and storing results

around two years.

for fast recall. The device logs a running average of the last 25 tests for SPC. If more data sets are needed, the

Faster moisture analysis

unit links via a USB cable to a PC running the com-

One focus of equipment development is increasing test speeds. Arizona Instrument is doing this for its Arizona Instrument’s Computrac Vapor Pro gauges the moisture content of materials

moisture-analysis systems. “Uncontrolled moisture content can cause a big problem for compounders,” Blaha remarks, “but most are relying on pretty old methods to test for moisture.” These include oven tests and rapid loss-on-drying methods. While both are reliable, oven techniques involve hazardous chemicals and require skilled operators. Loss-on-drying might be affected by additives in a compound, each of which has

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COMPOUNDING WORLD | September 2014

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