SRD SF-2 Electrically Actuated Pressure-Difference Moisture Analyzer
| Brand | SRD |
|---|---|
| Origin | Shanghai, China |
| Manufacturer Type | Authorized Distributor |
| Country of Origin | China |
| Model | SF-2 |
| Price | USD 1,950 (approx.) |
Overview
The SRD SF-2 Electrically Actuated Pressure-Difference Moisture Analyzer is a precision laboratory instrument engineered for the quantitative determination of trace-level bound moisture in thermoplastic polymer granules—particularly polyamide (PA6, PA66) and polyethylene terephthalate (PET) chips—prior to melt processing. It operates on the fundamental principle of pressure-difference measurement under controlled thermal desorption: a weighed sample is sealed in a calibrated glass test tube, heated to a specified temperature (typically 150–200 °C) under vacuum, and the vapor pressure increase resulting from moisture release is measured via a high-stability differential pressure transducer. This method isolates *chemically bound* or *lattice-trapped* water—not surface-adsorbed or equilibrium moisture—and correlates the pressure rise directly to mass of water evolved, using the ideal gas law and pre-calibrated system constants. Unlike Karl Fischer titration or coulometric electrolysis, the pressure-difference method requires no reagents, avoids interference from common solvents or alcohols, and delivers reproducible results within ±0.002 wt% for samples with moisture content below 0.03 wt%, which is critical for fiber-grade polymer quality assurance.
Key Features
- Electrically driven vertical lift mechanism for precise, repeatable positioning of the sample tube into the heating block—eliminating operator-induced variability associated with manual adjustment (SF-1)
- Integrated vacuum system with dual-stage rotary vane pump and stainless-steel manifold, achieving base pressure <5 Pa (0.038 Torr)
- Digital differential pressure sensor with resolution of 0.1 Pa and long-term zero stability (<±0.3 Pa/24 h)
- Programmable heating block with PID-controlled temperature regulation (range: ambient to 220 °C; accuracy: ±0.5 °C)
- Sealed quartz test tube assembly with borosilicate glass components and metal-sealed O-ring interface for leak integrity <1×10⁻⁷ mbar·L/s
- Compliance-ready design: supports audit trails, user access levels, and electronic signature logging when integrated with optional SRD DataMaster software
Sample Compatibility & Compliance
The SF-2 is validated for use with solid granular polymers including PET, PA6, PA66, PBT, and PC—materials where residual moisture induces hydrolytic degradation during extrusion or spinning. It is unsuitable for powders, liquids, or hygroscopic materials that release non-aqueous volatiles (e.g., plasticizers, residual monomers) at test temperatures. The method explicitly excludes equilibrium moisture assessment per ASTM D6980 and ISO 62, as it targets only non-equilibrated, structurally bound water. The analyzer conforms to the test protocols defined in GB/T 12006.2–2009 (Chinese national standard), ISO 960:1988 (Plastics — Polyamides — Determination of water content), and ISO 6188:1980 (Plastics — Poly(ethylene terephthalate) (PET) granules — Determination of water content). Its operational parameters meet GLP documentation requirements for QC laboratories under ISO/IEC 17025 accreditation.
Software & Data Management
The SF-2 operates standalone but is compatible with SRD DataMaster v3.2—a Windows-based application compliant with FDA 21 CFR Part 11 for electronic records and signatures. DataMaster enables automated calculation of moisture content (mg H₂O/g sample), real-time pressure/temperature curve plotting, method parameter storage (heating ramp, dwell time, vacuum hold), and export to CSV or PDF formats. All measurements are timestamped, user-ID logged, and include full metadata (sample ID, operator, calibration certificate ID, environmental conditions). Audit trail functionality records all data modifications, ensuring traceability for regulatory submissions and internal quality audits.
Applications
- Pre-spinning QC of PET and polyamide chips in synthetic fiber manufacturing
- Validation of dryer performance and residence time optimization in polymer drying lines
- Stability testing of vacuum-sealed polymer shipments (e.g., moisture ingress verification)
- R&D screening of new resin formulations for hydrolytic sensitivity
- Supporting ISO 10993 biocompatibility assessments where extractable moisture may affect leachables profiles
FAQ
What is the maximum measurable moisture mass?
The system is calibrated for absolute moisture quantification up to 1.5 mg per test—corresponding to ~0.03 wt% for a 5.0 g PET chip sample.
Can the SF-2 analyze samples containing volatile organic additives?
No. Co-evolution of non-aqueous volatiles invalidates the pressure-difference interpretation. Samples must be pre-screened for additive volatility or analyzed via complementary GC-MS.
Is routine calibration required?
Yes. Daily zero-pressure verification and quarterly full-system calibration using certified reference standards (NIST-traceable water-in-glycerol solutions) are recommended per ISO/IEC 17025 Clause 6.5.
Does the instrument support GMP-compliant reporting?
When used with DataMaster v3.2 and configured with role-based user accounts, electronic signatures, and disabled data deletion, it satisfies ALCOA+ data integrity principles for pharmaceutical-grade polymer excipients.
