Polypropylene for Spunbond: Grades, Properties and Supply

Polypropylene for Spunbond as an Industrial Raw Material Category

Polypropylene for spunbond production is a specialised group of polypropylene homopolymer grades designed for aerodynamic formation of continuous filament yarns followed by thermal bonding of the web. Unlike injection or film grades, spunbond polypropylene must have a narrow molecular weight distribution, stable melt flow rate and high purity, because filament formation occurs at high shear rates and temperatures, and die defects or melt heterogeneity lead to yarn breaks and web defects. The category specificity is determined by the fact that spunbond is formed in a single continuous process chain: melt extrusion, die with thousands of holes, aerodynamic filament drawing, web laydown and calender bonding. Each stage imposes requirements on polymer rheology. Stable spinnability and uniform filament distribution require grades with high flowability, low elastic turbulence and predictable cooling behaviour.

Chemical Identification and Classification

Spunbond polypropylene belongs to propylene homopolymers produced by stereospecific polymerisation on Ziegler-Natta or metallocene catalysts. In international trade, HS code 3902.10 is used. The CAS number for polypropylene as a class is 9003-07-0. Density of spunbond grades is in the range of 0.900 to 0.910 g/cm3, determined by the crystalline polypropylene phase. Classification is based on melt flow rate (MFR), which for spunbond typically ranges from 10 to 100 g/10 min at 230 degrees Celsius and 2.16 kg load, with an optimum for most industrial lines of 20 to 70 g/10 min. For fine fibres and high-speed lines, grades with MFR of 35 to 55 g/10 min and above are used; for thicker filaments and softer webs, 14 to 25 g/10 min. In Russian practice, PP grades for fibre and nonwovens are designated within GOST 26996-86, and only highest and first grade polypropylene is used for nonwovens, reflecting increased requirements for purity and property stability.

By purpose, hydrophobic (standard), hydrophilic, antistatic, UV-stabilised and coloured grades are distinguished. Hydrophobic polypropylene is the base for most applications because it naturally has low surface energy and is not wetted by water. Hydrophilic grades are produced by introducing masterbatches or additives that change surface tension, which is necessary for hygiene products requiring rapid liquid absorption. UV-stabilised grades are used for agricultural covers and geotextiles, antistatic grades for packaging and filtration. All additives must be compatible with polypropylene and must not cause agglomeration, which leads to web defects.

Regulatory Framework and Quality Standards

Circulation of spunbond polypropylene in the EAEU is regulated by Customs Union technical regulations, in particular TR CU 005/2011 for packaging, TR CU 007/2011 and TR CU 017/2011 for products in contact with children and skin, TR CU 021/2011 for food contact, TR CU 009/2011 for cosmetic packaging. For polypropylene itself, GOST 26996-86 Polypropylene and propylene copolymers. Specifications applies, establishing base grades, technical requirements, acceptance rules and test methods. For finished nonwovens produced from polypropylene, GOST R 58551-2019 for medical nonwovens and GOST R EN 13795 for surgical drapes, gowns and suits apply. These standards establish requirements for strength, air permeability, hydrophobicity and microbiological purity. International standards used for polymer control include ISO 1133 (melt flow rate), ISO 1183 (density), ISO 11357 (melting temperature by DSC), ASTM D1238 (MFR), ASTM D792 (specific gravity), ASTM D638 (tensile strength), ASTM D790 (flexural modulus).

Physico-Chemical Properties and Melt Rheology

Key physico-chemical parameters of spunbond polypropylene determine its behaviour in the extruder and during filament formation. The crystalline melting point is 160 to 165 degrees Celsius for homopolymer; metallocene grades can reach 163 to 165 degrees Celsius. The Vicat softening point is in the range of 150 to 155 degrees Celsius, heat deflection temperature at 0.45 MPa is about 85 to 100 degrees Celsius. Density is 0.900 to 0.910 g/cm3, ensuring the lightness of the finished web. Mechanical properties of the polymer in the finished web depend on filament drawing and thermal bonding, but base characteristics of homopolymer include tensile strength of 30 to 40 MPa, flexural modulus of 1400 to 1700 MPa, elongation at break of 10 to 150 percent. For spunbond, what matters is not only polymer strength but the ability of filaments to draw without breaks and retain orientation on cooling. Therefore melt rheology comes to the fore: at MFR below 10 g/10 min the melt is too viscous, filaments do not draw to the required diameter, breaks and thick spots are possible; at MFR above 100 g/10 min the melt is too fluid, leading to jet instability and reduced web strength.

The optimal MFR range for spunbond is 20 to 70 g/10 min, and the molecular weight distribution should be narrow to provide both good spinnability and sufficient filament strength. Metallocene grades with narrow MWD provide more uniform filaments and better web quality but require precise temperature profile adjustment. Chemical resistance of polypropylene is high: it is resistant to water, acids, alkalis, salts and most organic solvents, but has limited resistance to strong oxidisers and aromatic solvents at elevated temperatures. Prolonged UV exposure without stabilisers can cause photodegradation, which is critical for agricultural and geotextile applications.

Spunbond Production Technology and Polymer Requirements

The spunbond process begins with melting granules in an extruder and filtering the melt. The melt is forced through a die with a large number of fine round capillaries, after which filaments are drawn by air flow and laid on a moving belt. The formed web passes through a calender where it is thermally bonded at a temperature sufficient for partial melting of fibres but not destroying their orientation. Each stage imposes requirements on the polymer: stable viscosity in the extruder, absence of gels and additive agglomerates, rapid cooling and crystallisation of filaments, predictable behaviour during thermal bonding. For stable line operation, polypropylene must have low volatile content to avoid bubbles and surface defects, and minimal mechanical impurities that clog the die. Dust and moisture on granules are also unacceptable: moisture causes hydrolysis and micro-bubbles, while dust clogs filters and capillaries. Therefore, before extrusion, hot air drying at 80 to 100 degrees Celsius for 2 to 4 hours is recommended, especially for hydrophilic and compounded grades. The temperature profile across extruder zones is usually 200 to 230 degrees Celsius, and melt temperature at the die exit is 240 to 260 degrees Celsius, requiring polymer thermal stability and effective filtration.

Hydrophilic and Hydrophobic Grades: Differences and Applications

Hydrophobicity is a natural property of polypropylene and determines its use in barrier layers, medical gowns, protective covers and packaging where liquid repellency is required. Hydrophobic grades require no additional additives and provide stable water resistance but may accumulate static charge, which is important to consider in medical and cleanroom applications. Hydrophilic grades are produced by introducing surfactants or masterbatches that migrate to the filament surface and reduce surface tension. Such materials are used in hygiene products (diaper topsheets, sanitary pads, absorbent underpads) where rapid liquid transfer is important. Hydrophilicity must be stable over time and must not be washed out on contact with liquid. Additive introduction requires uniform distribution: additive agglomerates create areas with uneven wettability, leading to local leaks and defects. Antistatic and UV-stabilised grades are also functional and require additive compatibility with polypropylene.

Applications by Industry

Medicine and hygiene remain the largest consumers of polypropylene spunbond. Medical gowns, shoe covers, caps, masks, surgical drapes, sterilisation wraps and disposable sheets require hydrophobic grades with high purity and stable strength. Hygiene products - diapers, sanitary pads, absorbent underpads - use hydrophilic grades for topsheets and hydrophobic grades for barrier layers. Agriculture uses UV-stabilised spunbond for plant covers, mulching and frost protection, where resistance to photodegradation and mechanical strength are important. Construction uses spunbond for geotextiles, drainage membranes, windproof and waterproofing membranes, requiring strength, UV resistance and filtration properties. Packaging and logistics use spunbond for bags, covers, separators and protective wraps. Filtration uses spunbond as a base for air and liquid filters, where pore stability and chemical resistance are important. Furniture and textiles use spunbond as a lining and facing material. Each segment has different requirements for MFR, hydrophilicity and UV stabilisation, which determines grade selection.

Typical Web Defects and Their Link to Polymer Quality

The most common spunbond defects include uneven thickness (GSM variation), pinholes, filament breaks, additive agglomerates and uneven thermal bonding. Uneven thickness is often associated with melt pressure fluctuations, unstable temperature or uneven filament distribution across the web width. Pinholes occur due to die contamination, gels or additive agglomerates, as well as unstable spinnability. Filament breaks can be caused by raw material contamination, moisture, excessively high melt viscosity or insufficient drawing. Additive agglomerates are especially characteristic of hydrophilic and coloured grades: poor masterbatch dispersion leads to local areas with altered properties, manifesting as spots, uneven wettability and reduced strength. To prevent defects, grades with narrow MWD, stable MFR and good additive dispersion should be used, and drying, melt filtration and temperature profile should be controlled. Laboratory testing of the finished web includes measurement of surface density, tensile strength, elongation, air permeability, hydrostatic head and hydrophilicity (absorption time).

Quality Control and Laboratory Methods

Quality control of spunbond polypropylene includes incoming granule analysis, verification of accompanying documents and laboratory testing. Key polymer parameters: MFR (ISO 1133, ASTM D1238), density (ISO 1183), melting temperature (ISO 11357), volatile content, ash content, colour, mechanical impurities and additive content. For hydrophilic grades, stability of hydrophilicity after washing and absorption time are additionally assessed. For UV-stabilised grades, resistance to accelerated ageing is evaluated. Finished web testing includes surface density (GSM), tensile strength in machine and cross directions, elongation, tear resistance, air permeability, hydrostatic head (for medical barrier materials) and hydrophilicity. For medical products, microbiological and toxicological tests are mandatory. Laboratory confirmation is a mandatory element of supply, since polymer defects do not appear immediately but during processing or operation of the finished product.

Storage and Transportation Conditions

Spunbond polypropylene is stored in dry rooms protected from direct sunlight at temperatures not exceeding 30 degrees Celsius. Granules are moderately hygroscopic, so long-term storage requires protection from moisture. Bags and big bags must be sealed and protected from contamination. Shelf life in original packaging is usually 12 months, for some grades 6 months, after which quality may decline due to additive ageing and moisture accumulation. Transportation is carried out in 25 kg bags, 500 to 1000 kg big bags, octabins and containers. For export supplies, sea, rail and road routes are used with protection from moisture and contamination. When transporting in containers, moisture absorbers are recommended, especially for long routes and high-humidity conditions. Violation of storage conditions leads to caking, increased moisture and processing defects.

Analogue Selection and Interchangeability

Selection of an analogue for spunbond polypropylene is one of the key services of the portal. We help replace imported grades with comparable alternatives based on MFR, molecular weight distribution, hydrophilicity and spinnability stability. The algorithm includes analysis of the current grade and its rheological characteristics, determination of permissible deviations in key parameters, selection of options from available sources (Russia, China, other regions), verification of certificates and laboratory data, and organisation of trial batches for testing on the customer equipment. When selecting an analogue, not only MFR and density but also catalyst type (Ziegler-Natta or metallocene), MWD width, presence and type of additives, and melt behaviour at high shear rates are considered. For hydrophilic grades, additive stability and absence of agglomerates are critical. Grade replacement may require adjustment of temperature profile and drawing speed, so solutions with confirmed tests on the customer equipment are preferred. For medical and hygiene applications, certificates and sanitary approvals are mandatory.

Supply Scheme: Worldwide

The portal organises spunbond polypropylene supplies worldwide. The choice of source depends on the required grade, volume, timing, certification and economics. Russian producers provide base hydrophobic and hydrophilic grades, Chinese suppliers offer a wide range of grades with various additives and stable characteristics, and global sources allow obtaining specialised metallocene and UV-stabilised grades. Each supply is treated as a separate project with an individual scheme covering grade selection, quality verification, logistics and customs clearance.

Logistics and Customs Clearance

Spunbond polypropylene logistics includes sea, rail, road and multimodal routes. For large batches of granules, container and bulk schemes are optimal; for urgent deliveries, air and road transport. Customs clearance is supported by the portal broker: document preparation, HS code 3902.10 classification, certification and interaction with control authorities. The logistics scheme is built for the specific route and customer requirements, taking into account timing, cost and cargo safety. For medical and hygiene grades, compliance with sanitary requirements throughout the route is important.

FAQ

What melt flow rate is needed for spunbond?

The optimal MFR range for most industrial lines is 20 to 70 g/10 min at 230 degrees Celsius and 2.16 kg load. For fine fibres and high-speed lines, grades with MFR of 35 to 55 g/10 min and above are used; for thicker filaments, 14 to 25 g/10 min.

How does hydrophilic polypropylene differ from hydrophobic?

Hydrophobic polypropylene naturally repels water and is used in barrier layers and medical products. Hydrophilic polypropylene contains additives that reduce surface tension and provide rapid liquid absorption, which is necessary for hygiene products.

Can an imported grade be replaced with an analogue?

Yes, provided MFR, molecular weight distribution and additive type match. The algorithm includes rheology analysis, certificate verification and trial batches on the customer equipment.

What documents accompany a supply?

Conformity certificates, quality certificates, test reports, sanitary documents for medical and food applications, origin documents. For export batches, documents confirming compliance with the importing country requirements.

How should spunbond polypropylene be stored?

In dry rooms protected from light at temperatures not exceeding 30 degrees Celsius. Granules should be protected from moisture and contamination; for long-term storage, moisture absorbers are recommended.

Are small batches available for testing?

Yes, trial batches from 25 kg are available for most grades. Terms are agreed individually.

Conclusion

Polypropylene for spunbond remains a critical material for medicine, hygiene, agriculture and construction, where stable spinnability, predictable rheology and functional additives are required. A processor success depends on the correct choice of grade considering MFR, molecular weight distribution and hydrophilicity, confirmed quality and stable supply. The portal helps select analogues, organise logistics and customs clearance, ensuring supply chain transparency worldwide.

Contact Us

If you are looking for spunbond polypropylene or need advice on grade selection, analogue search and worldwide supply organisation, please contact our team at info@apptrade.ru. We will help you find the right product, verify documentation and organise supply.