Kraft paper is produced through the kraft (sulfate) pulping process, in which wood chips are cooked under high pressure in a solution of sodium hydroxide and sodium sulfide. This chemical treatment preserves the long cellulose fibers that give kraft paper its characteristic strength — a property that ordinary mechanical papers cannot replicate. The result is a material with a superior strength-to-weight ratio, outstanding tear resistance, and the ability to withstand the mechanical stresses of automated packing lines.
Within the broader category of specialty papers, industrial kraft sits at the intersection of structural performance and functional versatility. It serves as a raw substrate, a finished packaging material, and a converting feedstock — often within the same supply chain. Understanding its properties at a technical level is therefore essential for any business that relies on paper-based protective packaging.
The mechanical behavior of industrial kraft paper is governed by three primary test parameters recognized by ISO and TAPPI standards.
Tensile strength — measured in kilonewtons per meter (kN/m) — quantifies how much pulling force a paper strip can withstand before breaking. For industrial grades, this typically ranges from 5 kN/m at the lower end (light-duty wrapping) to 12 kN/m for heavy-duty sack and structural applications. The machine direction (MD) value is consistently higher than the cross direction (CD), a fiber-alignment effect that packaging engineers must account for when specifying folding and bag-forming orientations.
Burst strength (kPa·m²/g), measured via the Mullen Burst Test, reflects resistance to puncture under uniform hydraulic pressure. Industrial kraft grades designed for multi-wall sacks and pallet liners commonly achieve burst values in the 4–9 kPa·m²/g range. This property is particularly critical in agricultural and chemical sack applications, where point-load pressure from sharp granular contents can cause premature failure.
Elmendorf tear resistance (mN) measures the energy required to propagate an existing cut through a paper specimen. Industrial kraft typically registers 150–800 mN, with heavier basis weights and virgin-fiber grades sitting at the upper end of this range. Recycled-fiber grades often sacrifice some tear resistance in exchange for lower material cost and improved recyclability credentials.
| Property | Test Method | Light Grade (40–70 gsm) | Medium Grade (90–120 gsm) | Heavy Grade (150–300 gsm) |
|---|---|---|---|---|
| Tensile Strength (MD) | ISO 1924-2 | 5–6 kN/m | 7–9 kN/m | 10–12 kN/m |
| Burst Strength | ISO 2758 | 2–4 kPa·m²/g | 4–6 kPa·m²/g | 6–9 kPa·m²/g |
| Tear Resistance (MD) | ISO 1974 | 150–300 mN | 300–550 mN | 550–800 mN |
| Grammage Range | ISO 536 | 40–70 gsm | 90–120 gsm | 150–300 gsm |
| Typical Use Case | — | Interleaving, void fill | Bags, envelopes, wrapping | Sacks, pallet liners, cores |
One of the most consequential specification decisions for buyers is the choice between virgin kraft and recycled-content kraft. Both have distinct performance profiles and sustainability implications.
Produced entirely from fresh wood pulp — usually softwood species such as pine or spruce for their long fiber length — virgin kraft delivers the highest mechanical benchmarks in tensile, burst, and tear metrics. It is the material of choice for critical applications such as multi-wall cement sacks, chemical packaging, and export crating, where structural failure carries significant cost or safety risk. Its natural brown color, smooth surface, and consistent fiber distribution also make it well-suited to flexographic and gravure printing.
Recycled grades incorporate post-consumer or post-industrial waste paper fiber. Fiber shortening through repeated recycling cycles reduces peak mechanical strength but still yields material that meets most general-purpose packaging requirements. Modern closed-loop fiber sorting systems have improved consistency significantly, and recycled kraft can now achieve burst strengths adequate for e-commerce mailers, retail packaging, and light industrial wrapping. From a procurement perspective, recycled kraft typically carries a lower unit cost and a smaller carbon footprint per ton produced.
| Criterion | Virgin Kraft | Recycled Kraft |
|---|---|---|
| Fiber Source | Fresh softwood pulp | Post-consumer / post-industrial waste |
| Tensile Strength | Higher (long-fiber advantage) | Moderate (shorter fibers) |
| Surface Consistency | Very uniform | Slightly variable |
| Carbon Footprint | Moderate (managed forestry) | Lower (diverts waste from landfill) |
| Cost | Higher | Lower |
| Best For | Sacks, heavy industrial, export | E-commerce, retail, general wrapping |
Base kraft paper can be enhanced through a range of surface treatments that extend its functional envelope well beyond plain wrapping. Selecting the right coating is often the difference between a product that survives its supply chain journey and one that does not.
A thin extrusion-applied polyethylene layer transforms kraft paper into a moisture-barrier substrate suitable for frozen food cartons, construction wrap, and agricultural bags. Single-sided PE coating is sufficient for most applications, while double-sided PE lamination is used where condensation or liquid contact is a risk on both surfaces.
Paraffin or microcrystalline wax coatings provide low-cost water and grease resistance. Widely used in produce packaging and seafood applications, wax-coated kraft has been under commercial pressure in recent years due to recyclability concerns; however, it remains relevant in markets where cost is the primary driver.
Anti-rust VCI-treated kraft is specifically engineered for the metals packaging market. Volatile corrosion inhibitors migrate from the paper surface to form a mono-molecular protective layer on exposed metal components — such as automotive parts, bearings, and precision instruments — preventing oxidation during storage and transit. VCI kraft is one of the most technically sophisticated forms of industrial kraft paper, and its specification requires knowledge of the metal substrate, transit duration, and atmospheric conditions.
Standard kraft paper loses a significant portion of its tensile strength when wet, making it unsuitable for refrigerated logistics, outdoor construction sites, or beverage-adjacent packaging. Wet-strength agents — typically polyamide-epichlorohydrin (PAE) resins — are added during paper formation to create covalent crosslinks between cellulose fibers. Wet-strength kraft retains 30–50% of its dry tensile strength when saturated, a critical performance threshold for many demanding applications. This treatment is also found across Targanix's wet strength paper product line within the broader specialty papers range.
When selecting a coating, consider three variables: (1) the nature of the environmental stress (moisture, grease, abrasion, corrosion), (2) recyclability requirements mandated by your end market or brand commitments, and (3) compatibility with downstream converting operations such as printing, gluing, or heat sealing. A supplier capable of offering multiple coating options — as TGX Group does through its industrial papers program — reduces the qualification burden across your supply base.
Industrial kraft paper is supplied in two primary physical formats: rolls and sheets. Roll supply is standard for high-volume converting operations — bag-making machines, corrugator lines, lamination presses, and tube winders all consume paper from reels running at high line speeds. Sheet formats are preferred for manual packing stations, low-volume specialty applications, and smaller converters whose equipment cannot accommodate large-diameter rolls.
| Format | Width Range | Core Diameter | Typical Downstream Process |
|---|---|---|---|
| Roll (jumbo) | 300–2500 mm | 3" or 6" | Bag-making, corrugating, lamination, tube winding |
| Roll (slit) | Custom to spec | 3" or 6" | Automated wrapping, pallet systems, label backing |
| Sheet | Custom (A-series or industrial) | N/A | Manual packing, interleaving, flat-pack shipping |
Converting operations supported by industrial kraft paper include die-cutting, folding, scoring, gluing, heat sealing (on coated grades), and multi-wall lamination. Because paper exhibits directional fiber alignment, specifying the correct grain direction relative to the converting machine's feed direction is important — folding against the grain significantly increases fold-cracking risk at heavy basis weights.
In distribution center environments, kraft paper serves as pallet-layer sheets to prevent load shifting, void-fill material for corrugated cartons, and surface-protection wrapping for palletized goods. Automated paper void-fill dispensers — now common in large fulfillment centers — consume slit kraft rolls at high throughput rates, making reel consistency a procurement priority.
Consumer expectations for sustainable, minimal packaging have driven a significant shift away from bubble wrap and polystyrene toward kraft-based alternatives. Branded kraft mailer bags, honeycomb paper wrap (a converted kraft product), and tissue-paper infills all use industrial kraft as the primary substrate. The printability of natural brown kraft — or bleached white kraft for brand-sensitive applications — allows in-line printing of logos, handling instructions, and traceability codes.
VCI-treated kraft paper is a standard specified material for metal parts packaging within automotive supply chains, protecting components such as stamped steel panels, precision castings, and machined assemblies from corrosion during sea freight or warehouse storage. Non-VCI kraft is used for interleaving between stacked panels to prevent contact scratching.
Multi-wall kraft sacks — typically two to four plies — are the dominant packaging format for commodities such as flour, sugar, rice, animal feed, and seed. The multi-wall construction combines the strength of multiple kraft plies with optional PE or foil inner liners for moisture or oxygen barrier performance. Targanix's food packaging range extends these principles into coated and functional paper formats suited to direct-contact food applications.
Industrial chemicals, cement, fertilizers, and dry construction materials are among the highest-volume applications for heavy-grade kraft sacks. These products impose extreme demands: sharp granular particles, high fill weights (typically 25–50 kg per bag), and exposure to outdoor or semi-outdoor storage conditions. Burst strength and wet-strength retention are the critical performance metrics in this sector.
Industrial kraft paper functions as a substrate in several important converting chains: it forms the outer liner of corrugated fiberboard, serves as the base sheet for lamination processes (including silicone release liner manufacturing, a focus of Targanix's release paper product line), and provides the structural shell of paper tubes, cores, and edge protectors.
Sustainability in kraft paper packaging operates across three distinct dimensions: material origin, process chemistry, and end-of-life recyclability.
On material origin, FSC (Forest Stewardship Council) and PEFC (Programme for the Endorsement of Forest Certification) chain-of-custody certification provides documented assurance that virgin fiber comes from responsibly managed forests. These certifications are increasingly required by large retailers and consumer goods companies as part of their supply chain due-diligence commitments.
Process chemistry improvements have reduced the bleaching burden associated with white kraft production. Elemental chlorine-free (ECF) and totally chlorine-free (TCF) bleaching processes eliminate the dioxin risks associated with earlier chlorine-gas bleaching methods, making white kraft more acceptable from a life-cycle assessment perspective.
End-of-life recyclability is where kraft paper holds a clear advantage over most plastic alternatives. Uncoated kraft paper is accepted by virtually all standard industrial paper recycling streams. Coated variants require more care: PE-laminated kraft is technically recyclable through polyethylene film streams in some markets, while wax-coated kraft is generally not accepted by standard paper mills. This is a factor that informed procurement teams weigh against performance benefits when specifying coatings.
Targanix's dedicated sustainability program outlines how TGX Group integrates these principles across its product manufacturing, from raw material sourcing through to finished-product compliance.
Effective quality assurance for industrial kraft paper requires both incoming-goods inspection protocols and supplier qualification processes. The following checklist covers the parameters that most frequently arise in procurement and quality disputes.
| QC Parameter | Test Standard | Frequency | Notes |
|---|---|---|---|
| Grammage (basis weight) | ISO 536 | Every batch | ±3% tolerance is standard; tighter specs increase cost |
| Thickness (caliper) | ISO 534 | Every batch | Critical for die-cutting and lamination gap settings |
| Tensile Strength (MD & CD) | ISO 1924-2 | Every batch | MD/CD ratio indicates fiber alignment quality |
| Burst Strength | ISO 2758 | Every batch | Minimum threshold set to sack/bag end-use requirement |
| Tear Resistance | ISO 1974 | Every batch | Cross-direction tear often the limiting constraint |
| Moisture Content | ISO 287 | On receipt, climate-sensitive shipments | Target 6–8%; excess moisture reduces strength |
| Cobb Value (water absorption) | ISO 535 | For coated or treated grades | Low Cobb = higher moisture resistance |
| Roll Hardness / Winding Quality | Visual + Shore gauge | On receipt | Soft spots cause tension breaks on converting equipment |
Supplier qualification should additionally verify: certifications (ISO 9001, FSC/PEFC, food-contact compliance where relevant), mill capacity and lead times, and the availability of technical datasheets with guaranteed minimum property values rather than nominal or typical values.
TGX Group's quality control infrastructure and manufacturing technology are available for review on the Targanix website, providing documented transparency on production standards.
Industrial kraft paper does not exist in isolation — it is part of a wider category of engineered papers that converters and brand owners draw on depending on their specific functional requirements. Within Targanix's specialty papers portfolio, several product lines intersect with or complement industrial kraft:
Understanding this ecosystem helps procurement teams consolidate supplier relationships, reducing qualification overhead while maintaining material diversity across packaging applications.
The global industrial kraft paper market continues to benefit from sustained regulatory and commercial pressure against single-use plastics. EU Single-Use Plastics Directive compliance requirements and extended producer responsibility (EPR) schemes in North America and Asia-Pacific are accelerating the substitution of polyethylene films and bubble wrap with kraft-based alternatives. At the same time, the rise of direct-to-consumer e-commerce — with its demand for branded, lightweight, curbside-recyclable secondary packaging — continues to expand the addressable market for converted kraft products including mailer bags, honeycomb wrap, and paper cushioning systems.
On the supply side, capacity investment in virgin and recycled kraft pulp production has increased in South and Southeast Asia, diversifying geographic supply options beyond traditional Nordic and North American mill clusters. This is broadening the pool of qualified suppliers available to global buyers, though quality benchmarking and qualification processes remain essential to managing the risk of specification variance.
TGX Group — operating commercially as Targanix — is a China-based specialty paper and packaging material manufacturer headquartered at No. 358 Fengwu Road, Xincheng Town, Xiuzhou District, Jiaxing City, Zhejiang Province. The company's product portfolio spans release papers, self-adhesive label materials, and a comprehensive specialty papers range — including the industrial kraft paper packaging line covered in this article.
TGX Group serves a global customer base across the logistics, e-commerce, automotive, food & agriculture, chemical, and printing industries. Custom grades, formats, and coatings are available to specification, supported by documented quality control processes and technical datasheets.
Whether you need a standard industrial kraft grade or a custom-coated solution for a specific application, TGX Group's technical team is available to advise on material selection and provide detailed datasheets.
Phone: +86 18857360324 | Email: info@targanix.com
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