Solution for Measuring the Moisture Content of PA46 Material with a Halogen Moisture Analyzer | PA46 Moisture Content Measurement Method — VicoMeter | Jiangsu Victor Instrument Meter Co., Ltd.

VM-E01 Halogen Moisture Analyzer（0.1mg/0.0001g）

Background

Plastic part suppliers and their customers care about quality and fast production. Proper moisture in raw material ensures trouble-free compounding and molding, smooth surfaces, and ideal mechanical properties. The VicoMeter VM-E01 rapid halogen moisture analyzer is ideal for simple, accurate moisture measurement on the production floor.

Measuring moisture in plastics with a halogen moisture analyzer is a recognized ASTM method: D6980-12, "Standard Test Method for Determination of Moisture in Plastics by Loss in Weight".

A VicoMeter solution for typical PA46 (polyamide 46) samples: measuring their moisture with the VM-E01 rapid halogen moisture analyzer, including operating procedures.

Related Information

Before measuring PA46 samples with the VM-E01, you may also want to know:

Can a halogen moisture analyzer replace the oven method? Yes — seeCan Rapid Halogen Moisture Analyzers Replace the Oven Method?as discussed in that article.
How to choose a fast, accurate model? See"Rapid Halogen Moisture Analyzer Selection Guide"as discussed in that article.
Where to learn more about halogen moisture analyzers? See"Basic Knowledge of Rapid Halogen Moisture Analyzers"、"Explanation of Halogen Moisture Analyzer Technical Specifications"、《Halogen Moisture Analyzer》and other articles.
Other questions about measuring plastics? See the FAQ in"FAQ: Measuring Plastics with a Halogen Moisture Analyzer"as discussed in that article.

Common Questions About PA46 and Plastics

WKT-A9 Karl Fischer Trace Moisture Analyzer Coulometric

Reference Value Determination

The PA46 reference moisture value was determined with the VicoMeter WKT-A9 Karl Fischer moisture analyzer and WKT-V2 Karl Fischer oven; released moisture is carried by dry nitrogen into the electrolytic cell.

Recommended Settings for Plastics Industry Samples

If you have no reference method for plastics samples on the VM-E01, VicoMeter recommends these settings from experimental experience:

Heating mode: Standard
Shutoff mode: Automatic (1 mg/140 s)
Sample size: 30 g
Resolution: High (0.1 mg/0.0001 g)
Warm-up: standby, 100°C; at standby temperature, preheat the empty pan for 1 minute, then tare.

Selecting the Drying Temperature

Same Sample Heated at Two Different Temperatures

Figure 1: Same Sample Heated at Different Temperatures

(Click image to enlarge)

Choose a drying temperature matching the Karl Fischer reference value. Melting or marked color change means the temperature is too high. Some samples inevitably discolor when heated (polyamide unavoidably turns brown).

Figure 1 compares samples after two heating runs. Left: correct temperature — no melting or discoloration. Right: the sample browned, so the temperature was too high.

Plastic Sample Handling

Measure samples promptly. Otherwise, fill the container completely (use a smaller one if needed) and seal it to minimize air and prevent moisture uptake during storage.

Operating Steps for PA46 (Polyamide 46) Samples

Place the VM-E01 in a suitable spot, warm up 30 min, level it (bubble centered), and perform weighing and temperature calibration. Then measure PA46 samples (installation, environment, warm-up, calibration: seePreparation Before Formal Measurement with a Halogen Moisture Analyzeras discussed in that article; click the link to learn more.).

Halogen Moisture Analyzer Measurement Step: Taring

Tare Sample Pan

1. Place the empty pan on the center holder, preheat 1 min at 160°C standby, press tare to zero.

Halogen Moisture Analyzer Measurement Step: Spreading the Sample

Add Sample

2. Quickly spread about 30 g of PA46 sample evenly on the pan; wait for a stable reading.

One-Touch Start

3. Press start; the PA46 moisture result appears within minutes.

Test Data

VM-E01 Halogen Moisture Analyzer（0.1mg/0.0001g）

VM-E01 Settings Reference

Heating mode: Standard
Heating temperature: 160°C
Shutoff mode: Automatic (1 mg/140 s)
Sample size: 30 g
Resolution: High (0.1 mg/0.0001 g)
Warm-up: standby, 100°C; at standby temperature, preheat the empty pan for 1 minute, then tare.

Sample Information

Sample Description: PA46, beige, thermally stable.
Typical Maximum Allowable Moisture Content [%]: 0.05
Hygroscopicity (23°C/50% rH) [%]: 3.7

Moisture Chart for PA46 Samples Before and After Drying

Chart Notes

Recommendation: measure 6 PA46 samples with different moisture contents (dry vs. moist).
Green line:Moisture content (average) measured with the WKT-A9 Karl Fischer moisture analyzer and WKT-V2 Karl Fischer oven.
Blue line:Moisture content (average) measured with the VM-E01 rapid halogen moisture analyzer.
Red line:Typical maximum allowable moisture for pellet processing; refer to the supplier's material-specific values.

Moisture Data for PA46 Samples Before and After Drying

Sample Information	PA46 Moisture Content Before Drying		PA46 Moisture Content After Drying
Test Method	Halogen Moisture Analyzer	Karl Fischer Moisture Analyzers	Halogen Moisture Analyzer	Karl Fischer Moisture Analyzers
Moisture %MC	0.368	0.357	0.064	0.066
Std Dev Δ	0.003	0.007	0.002	0.002
Test Time [min]	45	30	11	30

Sample-Specific Test Notes

Maximum allowable moisture for pellet processing must always follow supplier specifications. Values here are typical only and may not suit your material or process.

These drying parameters were obtained on common plastics and do not cover all grades or colors; optimizing them may be needed for best results on a specific material.

FAQ

Can the Loss-on-Drying Method Measure Plastics?

Yes. Measuring moisture in plastics with a halogen moisture analyzer is a recognized ASTM method: D6980-12, "Standard Test Method for Determination of Moisture in Plastics by Loss in Weight".

Can a Rapid Halogen Moisture Analyzer Replace the Oven Method for Plastics?

Yes — seeCan Rapid Halogen Moisture Analyzers Replace the Oven Method?).

Can the same method for unreinforced plastics be used on reinforced plastics?

Yes — reinforced plastics contain glass or other materials that do not affect moisture measurement.

Can colorless-resin parameters be applied to a colored resin?

Adjust drying temperature for heat absorption — e.g., black resin about 10°C lower than white.

How to measure moisture in plasticized plastics?

Take care: loss on drying counts volatilized plasticizer as moisture. Heat at a lower temperature where possible to prevent plasticizer loss.

Can I apply my Karl Fischer oven temperature to the VM-E01?

Not directly. As a rule of thumb, the VM-E01 drying temperature is about 30°C lower than the oven's.

Can a method developed for one supplier's polymer be used on the same polymer type from other suppliers?

It is a good reference, but should be adapted to the other suppliers' polymer compounds.

Dr. Wei's Classroom

Poly(tetramethylene adipamide), i.e., polyamide 46, nylon 46, PA46, was first industrialized by DSM (Netherlands) in 1984. DuPont studied its synthesis in the 1930s (low molecular weight); solid-state polycondensation enabled high molecular weight in 1979; industrial production followed DSM's 1,4-diaminobutane process from acrylonitrile and hydrogen cyanide, with a 20,000 t/year plant by 1990. Production is mainly DSM-controlled; JSR, Teijin, and Unitika (Japan) also have capability via cooperation.