PP Welding Rod is a thermoplastic welding rod made of polypropylene (PP) resin through extrusion process. It is designed for plastic welding (such as hot air welding and hot melt welding) especially for pp sheet. Polypropylene is a semi-crystalline polymer material, which is generated by coordination polymerization or free radical polymerization of propylene monomer (CH₂=CHCH₃). Its molecular chain contains methyl side groups (-CH₃), which gives the material excellent chemical resistance, light weight and high rigidity. PP welding rods have a smooth surface (roughness Ra < 0.1μm), uniform color (commonly milky white, translucent or black, custom colors are supported), and a density as low as 0.90-0.91g/cm³ (about 90% of water). The diameter range is usually 2.5mm to 5mm (common specifications are 3mm, 4mm, 5mm), and the length can be customized according to needs. According to the different molecular structures and additives, it can be divided into homopolymer PP welding rods (high rigidity, low impact resistance), copolymer PP welding rods (high impact resistance, low temperature toughness) and reinforced PP welding rods (adding glass fiber or mineral fillers to improve strength and heat resistance). They are widely used in the welding repair and manufacturing of chemical storage tanks, plastic pipes, automotive parts and civilian plastic products.
Product performance
Mechanical properties
Lightweight and high rigidity: Density 0.90-0.91g/cm³ (about 1/7 of steel and 1/2 of aluminum), light and easy to process; tensile strength 30-40MPa (homopolymer PP) or 20-30MPa (copolymer PP), flexural modulus 1200-1800MPa, suitable for weight-sensitive welded parts (such as plastic pallets and brackets) that require a certain structural strength.
Medium impact resistance: Simple beam notch impact strength 5-15kJ/m² (copolymer PP is modified by ethylene copolymerization, and low-temperature toughness is significantly improved), can resist general impact (such as slight collisions in logistics transportation) at room temperature to -20℃, but lower than engineering plastics (such as PA, POM).
Excellent creep resistance: small deformation under long-term static load (deformation rate under 1000 hours load <2%), suitable for welding structures that withstand continuous pressure (such as plastic flange connections).
Thermal properties
Medium heat resistance: heat deformation temperature (under 1.82MPa load) 90-110℃ (homopolymer PP) or 50-80℃ (copolymer PP), short-term resistance to high temperature of 120℃ (such as hot water immersion), long-term use temperature range of -20℃ to 100℃, suitable for welding and repair of hot water pipes and food processing equipment.
Low thermal conductivity: thermal conductivity 0.1-0.2W/(m·K) (about 1/50 of metal), it is an excellent thermal insulation material (such as insulation box welding seal).
Chemical properties
Excellent chemical corrosion resistance: stable to most acids (such as sulfuric acid, hydrochloric acid), alkalis (such as sodium hydroxide), salt solutions and organic solvents (such as ethanol, acetone) (no significant swelling when the concentration is <30%), only not resistant to concentrated sulfuric acid, concentrated nitric acid and halogenated hydrocarbons (such as carbon tetrachloride), suitable for welding and repair of chemical storage tanks and laboratory utensils.
Non-toxicity: Complies with FDA and EU 10/2011 food contact safety standards, can be directly in contact with food (such as plastic pipe welding seals), no odor release.
Electrical properties
Excellent insulation: Volume resistivity ≥10¹⁵Ω·cm, dielectric strength 20-30kV/mm, dielectric constant 2.2-2.6 (1kHz), suitable for welding of low-voltage electrical insulation components (such as switch housings, junction boxes).
Processing performance
Easy to weld: Melting temperature 160-170℃, good fluidity during hot air welding or hot melt welding (melt flow rate MFR 1-5g/10min), welding strength can reach 80%-95% of the parent material (standard operation required), suitable for on-site repair and factory manufacturing.
Low shrinkage: Shrinkage after welding <1.5% (better than ordinary plastic welding materials), high dimensional stability (reduces the risk of welding deformation).
pp welding rod for polypropylene sheet processing
Specific application parts
1. Chemical tank weld repair: used for weld repair of plastic tanks (such as PP and PVC tanks) storing corrosive media such as sulfuric acid, hydrochloric acid, and alkali. The chemical resistance of PP welding rods (resistance to acid/alkali solutions with a concentration of <30%) ensures long-term sealing of the welds and avoids leakage risks.
2. Plastic pipe hot melt welding: used for the connection and repair of PPR pipes and PVC pipes. The low melting temperature (160-170°C) and fluidity of PP welding rods enable them to be quickly welded by hot melt welding guns (welding time <30 seconds/meter), and the weld strength is >90% of the parent material.
3. Automobile bumper welding repair: used for crack or damage repair of PP bumpers. The high impact resistance (excellent low-temperature toughness) and energy absorption characteristics (energy absorption rate >60%) of copolymer PP welding rods enable the repaired bumpers to withstand low-speed collisions (in line with NCAP test standards).
4. Automotive interior welding: used for the seam welding of instrument panel brackets and door panel linings. The low shrinkage rate (<1.5%) of PP welding rods ensures that the welds are not deformed (improving the aesthetics of the interior), while the high elasticity (elongation at break>500%) buffers vibration noise (reducing the noise inside the car by 5-10dB).
5. Automotive plastic pipe welding: used for the connection and repair of air-conditioning pipes and coolant pipes. The chemical corrosion resistance (resistance to refrigerant erosion) and temperature resistance (short-term tolerance to 120°C) of PP welding rods ensure long-term sealing of the pipes (service life>8 years).
6. Plastic pipe hot-melt connection: used for welding PPR pipes and CPVC pipes in building water supply and drainage systems. The low melting temperature (160-170°C) and easy operability of PP welding rods (can be completed with a hot-melt welding gun) increase construction efficiency by more than 50% (compared with PVC pipe solvent adhesive).
7. Plastic flange connection welding: used for sealing welding of plastic flanges (such as PP flanges) of chemical equipment and environmental protection equipment. The high rigidity (flexural modulus 1200-1800MPa) and chemical resistance of PP welding rods ensure long-term leakage-free flange connection (sealing pressure > 0.6MPa).
8. Plastic bearing seat repair: used for repairing cracks in plastic bearing seats of motors, fans and other equipment. The self-lubrication (friction coefficient 0.3-0.4) and creep resistance (deformation rate under 1000 hours of load < 2%) of PP welding rods reduce maintenance requirements (service life > 3 years).
9. Industrial plastic container welding: used for weld reinforcement of plastic water tanks and chemical barrels. The hydrolysis resistance (resistance to long-term water immersion) and weather resistance (no aging for 10 years of outdoor use) of PP welding rods improve container reliability (service life > 15 years).
