The product Bada BADAMID PA12 H UV natural PA12, Dry is a natural, heat-stabilised and UV-stabilised polyamide 12 compound supplied as sealed, dry-state granules. The PA12 portion of the designation refers to polyamide 12 as defined in ISO 1043-1:2001. The H suffix denotes heat-ageing stabilisation, UV denotes ultraviolet stabilisation, natural denotes an unpigmented formulation, and Dry indicates a controlled residual moisture content before packaging. This grade is intended for injection moulding and extrusion applications requiring lower moisture uptake than PA6 or PA66, chemical resistance to aliphatic hydrocarbons when evaluated by ISO 1817, and retention of impact toughness at sub-zero temperatures. Representative class-level dry-state values for unreinforced PA12 include a density of 1.01–1.02 g/cm³ according to ISO 1183-1, a melting peak from 175 °C to 180 °C according to ISO 11357-3, and saturation water uptake of approximately 1.6 % by mass according to ISO 62. Published data for this exact Bada configuration is limited; the values quoted here are class-level PA12 values and must be verified against the lot certificate for the grade.

How Does Moisture Uptake and Drying Set the Process Window?

Residual moisture in PA12 activates hydrolytic chain scission during melt processing. The dry-state designation is generally associated with a residual moisture content below 0.10 % by mass, measured by Karl Fischer titration according to ISO 15512. Once the original sealed packaging is opened, the granulate adsorbs atmospheric moisture; at 23 °C and 50 % relative humidity the equilibrium moisture content approaches 0.7 %. Melt-processing above 0.15 % residual moisture produces splay, weld-line porosity, and viscosity reduction on injection moulding machines with screw diameters from 25 mm to 60 mm and L/D ratios from 20:1 to 25:1. On production lines with open material hoppers, moisture regain can occur within 30–60 min when the ambient dew point exceeds 10 °C; therefore, direct hopper-to-press loading is preferred after drying.

Desiccant drying at 80 °C for 4–8 h with a dew point of -30 °C or lower reduces residual moisture to below 0.10 %. Overdrying at 80 °C is less critical for PA12 than for PA6 or PA66, but extended heated residence can shift the molecular weight distribution and increase the proportion of low-molecular-weight oxidative species. In extrusion, a single-screw extruder with a grooved feed section and L/D ratio of 24:1 to 30:1 is preferred; the first barrel zone is maintained at 220–240 °C to limit pre-melting and feed-blocking. If wet feedstock enters a vented extruder, hydrolysis products are only partially removed and the extruded strand can show surface roughness, diameter fluctuation, and reduced burst pressure in downstream tube production.

For tube and profile extrusion, the moisture limit is often more stringent than for injection moulding because surface defects in continuous extrusions cannot be hidden by the mould surface. A dew-point transmitter in the dryer return air should be used to verify that the desiccant bed is not exhausted; return-air dew points above -20 °C reduce drying efficiency. Closed-loop vacuum or membrane dryers with independent regeneration are preferred when ambient humidity exceeds 60 % RH. Hydrolysis follows pseudo-first-order kinetics at melt temperature; the rate is proportional to water concentration and residence time. The practical limit of 0.10 % is therefore not a single-point guarantee but a processing boundary that protects the molecular weight distribution.

Melt rheology, screw design, and thermal degradation limits

For dry-state PA12 H UV natural, melt temperature is set between 230 °C and 270 °C for injection moulding and between 225 °C and 255 °C for profile or tube extrusion. Below 230 °C, semi-crystalline PA12 may not fully homogenise in short screw lengths, producing unmelted granules and flow lines. Above 270 °C, thermo-oxidative degradation becomes measurable; at residence times longer than 10 min, yellowing and a decrease in melt viscosity can occur even in heat-stabilised systems. The processing range is therefore narrower than for some short-chain polyamides; barrel heaters should be controlled in zones and the melt temperature should be confirmed with an immersion thermocouple rather than assumed from barrel setpoints.

Mould temperature controls crystallisation and post-mould shrinkage. A tool temperature of 40–80 °C is typical for unfilled PA12. Lower mould temperatures below 40 °C reduce cycle time but increase frozen-in orientation and can lower impact resistance. At 60–80 °C, the crystallisation rate increases and the moulding can be ejected with more stable dimensions. The screw and barrel boundaries for injection moulding are shown in the table below. Published data for the specific Bada BADAMID PA12 H UV natural PA12, Dry lot may differ; the table should be verified against the supplier certificate.

On injection moulding machines, screw-back pressure in the range of 0.5–1.5 MPa and screw speed of 80–200 rpm are starting points for uniform melt quality; excessive back pressure above 1.5 MPa can raise melt temperature and degrade heat-sensitive natural PA12. The shot size should use 30–70 % of the barrel capacity to limit residence time. Nozzle temperature should be kept near the front-zone setpoint; drool can be controlled with decompression of 2–5 mm. Injection speed is adjusted to avoid shear-induced splay at gates; high shear rates above 100 000 s⁻¹ can cause localised melt fracture and visible streaks in natural grades.

The semi-crystalline morphology of PA12 develops during cooling. Slow cooling in thick sections can increase spherulite size and reduce impact; fast cooling can produce lower crystallinity and lower modulus. Mould temperature and wall thickness therefore interact in a way that cannot be captured by melt temperature alone. Post-mould annealing at 120–140 °C for 2–4 h may be required for tight-tolerance parts, but this procedure should be validated for the natural UV-stabilised grade because annealing can alter surface appearance.

Thermal ageing resistance conferred by the H package is not unlimited. Heat-stabilised PA12 grades in this class are commonly tested by ISO 188 accelerated ageing; tensile elongation and Charpy impact are the sensitive indicators. Dry-state PA12 should not be continuously exposed to hot air above 120 °C without application-specific lifetime testing, because oxidative degradation eventually reduces elongation at break. UV stabilisation retards photo-oxidative chain scission, but natural unpigmented grades remain more sensitive to long-term UV exposure than carbon-black-filled grades; colour change and surface microcracking can appear after extended outdoor weathering under ISO 4892-2 test conditions.

For substitution decisions involving PA6, PA66, or PA11, the primary differentiators are moisture absorption, melt temperature, stiffness, chemical resistance, and low-temperature toughness. The comparative matrix below presents class-level dry-state values for unreinforced long-chain and short-chain polyamides; it is not a guarantee for the Bada grade and is provided for engineering screening.

Compared with unreinforced PA6 and PA66, PA12 H UV natural shows lower tensile modulus and lower dry-state tensile strength but lower water uptake and lower mass gain in zinc chloride immersion tests conducted to ISO 175. At saturation, PA6 and PA66 water absorption can reach approximately 9.5 % and 8.5 % respectively under ISO 62, whereas PA12 remains near 1.6 %. The lower equilibrium moisture uptake reduces the shift from dry-as-moulded to conditioned service and improves dimensional stability in humid air. Dimensional change is commonly measured by ISO 62 and by linear mould shrinkage determination in ISO 294-4; lower moisture uptake does not eliminate all dimensional movement, but it reduces the magnitude of the dry-to-conditioned transition.

Against PA11, PA12 has a slightly lower melting range (175–180 °C versus 185–190 °C) and comparable moisture uptake. Published data for direct Bada PA12 H UV natural comparison with specific PA11 grades is limited; selection should include fluid immersion testing to ISO 175 and ISO 1817 rather than polymer-class assumptions alone. In fuel-contact applications, the failure mode can shift from swelling to environmental stress cracking, so test specimens should be moulded under production-representative gate and packing conditions.

When PA12 H UV Replaces PA6 or PA66 in Low-Temperature Impact Applications

In automotive and industrial fluid-handling components, replacement of PA6 or PA66 with PA12 H UV natural is usually driven by moisture absorption, dimensional stability, chemical resistance to aliphatic hydrocarbons, and low-temperature impact. PA12 maintains measurable notched impact strength at temperatures below -30 °C; the exact lot-specific value must be taken from the certificate. For fuel-contact parts, the long-chain polyamide is generally evaluated against ISO 175 and ISO 1817 with the actual service fuel, because oxidative and acidic fuel impurities can shift the failure mode from swelling to stress cracking. PA12 tends to exhibit lower brittleness in dry cold environments, as indicated by notched impact testing under ISO 179-1/1eA, but low-temperature flexibility is also influenced by plasticizer content and moulded-in orientation.

The material is used where lower stiffness is acceptable: cable ties, clips, connectors, tubing, and housings. For load-bearing structural parts, unreinforced PA12 has dry-state tensile modulus in the range of 1400–1700 MPa, which is lower than that of unreinforced PA6 or PA66; glass-fibre-reinforced grades are required for higher stiffness. The natural colour enables laser marking and colour compounding; however, colour concentrates should be dried with the base resin and carrier compatibility should be confirmed at the let-down ratio used on the production line. In multi-cavity hot-runner moulds, the use of natural PA12 requires thorough colourant dispersion and consistent hot-runner temperature balancing to avoid visible flow streaks and gloss variation; hot-runner nozzle temperatures should not exceed 270 °C.

For extrusion of PA12 tube and cable jackets, the melt temperature is usually kept in the lower half of the range to increase melt strength and reduce drawdown. Downstream sizing in vacuum water baths with 60–80 °C water is common; the vacuum level and haul-off speed are set to match the required outside diameter and wall thickness. Bada BADAMID PA12 H UV natural PA12, Dry in natural colour can be laser marked after processing, but marking contrast should be validated on production-line samples because surface moisture and crystallinity affect the mark.

Regulatory Boundary Conditions and Handling Limitations

Compliance must be verified for the exact grade and batch. Polyamide 12 grades in this class may be reviewed for REACH registration and RoHS Directive 2011/65/EU. Food-contact or medical-grade status under FDA 21 CFR 177.1500 or European food-contact legislation should not be assumed for this natural dry-state product without written confirmation from the supplier. The grade is not automatically suitable for potable-water contact; product-specific certification to national plumbing standards must be obtained when required.

Operational boundaries include incompatibility with strong oxidising acids, concentrated formic acid, phenols, and high-pressure steam above 140 °C. Contact with zinc chloride solutions is generally reported as less aggressive than for PA6 or PA66, but immersion testing to ISO 175 is required for each fluid. The granulate must be stored in sealed packaging at 15–30 °C; if the ambient warehouse humidity exceeds 60 % RH, drying is necessary after opening and before processing. Bada BADAMID PA12 H UV natural PA12, Dry should not be processed without verifying the lot-specific moisture content, melt flow rate, and mechanical properties against the supplier certificate.