Evonik VESTAMID L2123 sw 9.7507 is a black-pigmented, unreinforced, semi-crystalline polyamide 12 (PA 12) grade. The base-grade designation VESTAMID L2123 identifies the molecular architecture, melt viscosity, and stabilization package; the suffix “sw 9.7507” identifies the black color specification in the manufacturer’s nomenclature and does not describe glass-fiber reinforcement, mineral filler, or elastomer modification. In datasheets where this grade is reported under “dry properties,” the mechanical values correspond to specimens dried to a moisture content below 0.1% by mass and tested before conditioning at standard atmospheres. The principal standard used for accelerated drying is ISO 1110, while mechanical testing is normally performed under ISO 527-1/-2 at 23 °C. Dry-as-molded data provide a reproducible baseline for lot acceptance but are not equilibrium service values. At 23 °C/50% RH, unreinforced PA 12 absorbs approximately 0.7–0.9% moisture by mass; the absorbed water softens the amorphous phase, reducing tensile modulus and yield stress while increasing elongation at break and notched impact energy. A freshly molded clip or tube made from this grade will therefore lose measurable stiffness during the first weeks of humid service before stabilizing.

The grade is supplied as cylindrical granules suitable for injection molding and profile or tube extrusion. The carbon black associated with the 9.7507 color specification absorbs ultraviolet radiation across the 300–400 nm band and reduces surface chalking and embrittlement in exterior applications. Carbon black pigmentation also raises electrical conductivity relative to natural PA 12, but the surface resistivity remains too high for most antistatic or ATEX-relevant dissipation requirements unless an explicit conductive modification is specified. Therefore the black pigmentation should be treated as a UV-stabilizing and color-identity feature, not as an electrically functional additive.

For early material selection, the following dry-state envelope is appropriate for unreinforced PA 12 grades of the VESTAMID L2123 type. Lot-specific certificates of analysis control over these class-typical bands because color concentrates and stabilization can shift values by several percent.

What Is the Practical Risk of Comparing Dry and Conditioned Nylon 12 Data Without Accounting for Moisture?

Moisture conditioning affects not only tensile properties but also flexural modulus, hardness, and impact behavior. A component designed to a dry flexural modulus may exhibit a drop of 30–40% after conditioning at 23 °C/50% RH. This shift is especially important in snap-fit clips and push-connect fluid fittings, where reduced stiffness changes retention force and insertion effort. The moisture uptake is diffusion-controlled; thin-walled tubing with wall thickness below 1 mm can approach equilibrium within 14–28 days, while solid injection-molded bosses above 4 mm may require several months. If short-term tests are used to qualify parts, the conditioning protocol must be stated explicitly; otherwise dry-property data may incorrectly predict long-term retention force. For comparative studies, moisture uptake should be reported according to ISO 62, and mechanical data should include the conditioning atmosphere, time, and specimen thickness. When torque retention or press-fit load is a critical design requirement, parts should be re-tested after moisture equilibration rather than relying solely on dry-as-molded tensile values.

Pre-drying should be performed in a dehumidifying hopper dryer using air with a dew point at or below −30 °C. The recommended drying temperature is 80 °C for 4–8 hours to reach residual moisture below 0.1%. Melt temperature for VESTAMID L2123-type PA 12 is usually set between 220 °C and 250 °C, with a flat-to-modest rear-to-front barrel profile. In single-screw extrusion for small-bore tubing, a general-purpose polyamide screw with L/D ratio of 24:1 to 30:1 and compression ratio 2.5:1 to 3.0:1 is considered suitable. In injection molding, clamp force requirement follows standard thin-wall polyamide practice; melt residence time above 10 minutes at melt temperature should be avoided to prevent molecular weight loss and discoloration of the polyamide backbone. A mold temperature of 40–80 °C is typically applied for unreinforced PA 12 to achieve adequate crystallinity and dimensional stability. Lower mold temperatures reduce cycle time but produce a less crystalline skin and can increase clamp force variability. Higher mold temperatures above 80 °C improve part flatness but extend cooling time. Published data for output rates and pressure drops on production-scale lines using VESTAMID L2123 sw 9.7507 with defined screw designs are limited, so processing windows should be validated on the actual extruder or molding machine.

Comparative Position of PA 12 Against PA 66 and Thermoplastic Polyurethane

The primary structural reason for the different dry mechanical behavior is amide group concentration. PA 12 has an alkane segment of 11 methylene units between repeating amide groups, whereas PA 66 has shorter aliphatic sequences and higher amide density. The lower amide density produces a dry tensile modulus in the 1,400–1,800 MPa range for unreinforced PA 12, compared with 3,000–3,500 MPa for unreinforced PA 66 measured under identical ISO 527-1/-2 conditions. Moisture conditioning shifts both materials downward, but the higher water absorption of PA 66 means its conditioned modulus can fall by 40–50%. PA 12 typically loses 30–40% of its dry modulus at equilibrium. Consequently, the dry modulus difference is not fully retained in humid service.

When Black Pigmentation Interacts with Joining and UV Resistance

In through-transmission laser welding, the black side absorbs the laser and the transmissive side must be sufficiently transparent at the laser wavelength, usually 800–1100 nm. VESTAMID L2123 sw 9.7507 is suitable as the absorbing partner only; it should not be used as the transmissive side. For ultrasonic welding and hot-plate welding, the carbon black does not fundamentally prevent joining, but weld-line appearance and energy-director collapse can shift because black pigmentation changes melt surface absorption and thermal diffusivity. Validation under production vibration amplitude and collapse distance is required.

In exterior line systems, black PA 12 is often preferred over natural or colored PA 12 because carbon black interrupts photo-oxidative radical propagation. This does not remove the need for transition-metal and heat stabilization packages required for long-term thermal aging in vehicle underhood or engine-compartment applications. For continuous use above 100–110 °C, PA 12 grades can undergo thermo-oxidative embrittlement unless stabilizer systems are matched to the exposure time and air-flow conditions.

Typical applications for VESTAMID L2123 sw 9.7507 include small-bore pneumatic tubing, fuel-vapor and vent lines, cable sheathing, and injection-molded clips and fasteners exposed to road splash. In pneumatic tubing, the material provides cold flexibility and resistance to zinc chloride stress cracking; in fuel-vapor service, the grade is used for its low moisture uptake and lower permeation relative to PA 6. For automotive line systems, conformance to applicable fuel and vapor tube assembly standards such as SAE J2260 is not automatic and depends on construction, wall thickness, and connector design. Where medical or food-contact use is considered, grade-specific regulatory confirmation against FDA 21 CFR 177.1500 or USP Class VI is required for the exact black color lot, because pigment and additive packages can fall outside the listed resin formulation. Compliance to REACH Regulation (EC) No 1907/2006 and Directive 2011/65/EU (RoHS) is supplier-declared for the product; end manufacturers must verify application-specific thresholds. The grade is not suitable for continuous contact with concentrated mineral acids, phenol, or high-pressure steam above 110 °C. It should not be selected for structural load-bearing parts requiring dry flexural modulus above 2,000 MPa unless geometry or reinforcement compensates for the lower stiffness.