CPP film density typically ranges from 0.90 to 0.92 g/cm³, which is a fundamental physical property that significantly influences the material’s barrier properties, mechanical strength, transparency, and overall performance in packaging applications.
This value is critical for manufacturers and engineers who need to calculate material weight, estimate costs, and ensure product consistency in cast polypropylene film production.
For packaging buyers and engineers, understanding this 0.90–0.92 g/cm³ window makes it much easier to estimate film grammage, compare CPP with other substrates, and verify whether a supplier’s technical data sheet is realistic.
In this guide, we focus on how CPP film density connects to real-world packaging decisions—helping you choose the right grade, calculate yield and roll weight more accurately, and reduce trial-and-error during development.
As a specialist flexible-packaging supplier, CloudFilm combines density control with tight thickness tolerances and stable COF so that CPP rolls run smoothly on VFFS, HFFS and flow-wrap lines.
What is CPP Film?
Cast Polypropylene (CPP) film is produced through a melt casting quenching process, resulting in a non-stretched, non-oriented flat film. It is manufactured using T-die extrusion followed by rapid cooling on cooling rollers, which gives it excellent thickness uniformity, high transparency, and good heat sealability.
CPP films are classified into three main categories: general purpose, metallized grade, and retort grade, with retort-grade films capable of withstanding high-temperature sterilization at 121°C-135°C.
In practical packaging, CPP is widely used as a sealing web or inner layer in structures such as PET/CPP, BOPP/CPP and BOPE/CPP, as well as in mono-layer garment bags, tissue overwraps and simple pillow packs.
Within CloudFilm’s dedicated CPP film portfolio, cast CPP grades are typically supplied in thicknesses from about 20–60 µm, tailored to flow-wrap, lamination and pre-made pouch applications in food, tissue, garment and industrial markets.
If you need both CPP and CPE from a single source, CloudFilm can also provide cast film solutions that integrate CPP sealing layers with CPE for tougher or softer structures, depending on your application.
The Significance of Density in CPP Films
Density is a crucial property of CPP films that affects multiple aspects of its performance:
Barrier Properties: Density directly influences the film’s resistance to moisture vapor and gases. Higher density generally improves barrier performance but may reduce flexibility.
Mechanical Strength: Denser films typically exhibit better tensile strength and stiffness, which is important for packaging durability.
Optical Characteristics: Density affects the film’s transparency and haze, with optimal density values providing superior clarity.
Cost Calculations: Density is essential for calculating the weight of film required for specific applications, directly impacting material costs.
From a commercial perspective, density is the bridge between lab data and business results: it influences how many packs you get per kilogram, how many rolls fit on a pallet, and how confidently your team can compare quotations from different CPP suppliers.
CloudFilm’s technical team routinely reviews density together with thickness, COF, seal strength and haze to ensure that CPP specifications are not only technically correct but also cost-effective for your line speed and market positioning.
Using CPP Film Density For GSM, Yield And Roll Weight Calculations
In daily work, most engineers convert density into three very practical numbers: basis weight (GSM), yield (m²/kg) and estimated roll weight. For CPP at ρ≈0.91 g/cm³, a useful shortcut is:
- GSM (g/m²) ≈ 0.91 × thickness (µm)
- Yield (m²/kg) ≈ 1000 ÷ (0.91 × thickness)
- Roll weight (kg) ≈ width (m) × length (m) × thickness (µm) × 0.91 × 0.001
Example: a 30 µm CPP web at ρ=0.91 g/cm³ has GSM ≈ 27.3 g/m² and yield ≈ 36.6 m²/kg. If your roll is 0.6 m wide and 3,000 m long, roll weight is roughly 0.6 × 3000 × 30 × 0.91 × 0.001 ≈ 49.1 kg (plus core).
For multi-layer laminates (e.g. PET/CPP), you can first calculate the average density ρ_avg from each layer, then apply the same formulas. CloudFilm’s sales engineers often help customers run these calculations so quotations and logistics plans are based on realistic roll weights and yields.
If you need more detailed worked examples and reference tables for different polymers (PP, PE, PET, PA, EVOH, PVDC), you can also check our dedicated guide on flexible film density formulas and yield.
Typical Density Values for Different CPP Film Types
The density of CPP films can vary slightly depending on the specific formulation and intended application. The following table summarizes typical density ranges for different CPP film types:
| CPP Film Type | Density Range (g/cm³) | Key Characteristics | Common Applications |
|---|---|---|---|
| General Purpose CPP | 0.90-0.91 | Good clarity, stiffness, and heat sealability | Food packaging, clothing, stationery |
| Metallized Grade CPP | 0.91-0.92 | Excellent metal adhesion, high barrier properties | Snack foods, coffee, pharmaceutical packaging |
| Retort Grade CPP | 0.90-0.92 | High temperature resistance, good impact strength | Sterilized food packages, medical device packaging |
| High Transparency CPP | 0.90-0.91 | Superior clarity, low haze | Premium packaging, display packaging |
Table 1: Typical density ranges and characteristics of different CPP film types
When you compare these grades, density is one of the parameters that helps you decide whether a film is better suited as a clear mono-layer bag, a high-barrier metallized web, or a heat-resistant retort sealing layer.
CloudFilm can fine-tune CPP structures within these density windows while adjusting slip, anti-block and sealing performance so that the same film works reliably on your existing packaging lines without extensive re-qualification.
Factors Affecting CPP Film Density
Several factors influence the density of CPP films during manufacturing:
Polymer Selection: The choice of polypropylene homopolymer or copolymer affects density. Homopolymers generally have higher density than copolymers.
Additives: Incorporation of additives like slip agents, anti-block agents, and nucleating agents can slightly modify the film’s density.
Processing Conditions: Cooling rate during film formation significantly affects crystallinity, which directly influences density. Faster cooling typically results in lower density due to reduced crystallinity.
Multilayer Structure: In co-extruded films, the density of individual layers may vary based on their composition, affecting the overall film density.
For a given nominal density, CloudFilm can adjust these levers—resin type, additive package and chill-roll conditions—to balance density with other key properties such as COF, seal strength, and optical clarity.
This process control is especially important when you move from small laboratory lines to wide, high-speed industrial cast lines where even slight changes in crystallinity can shift density and film behavior.
Measurement Methods for CPP Film Density
The density of CPP films is typically measured using standardized test methods:
Density Gradient Column: This is the most common method, where film samples are placed in a column filled with liquids of varying densities to determine where the sample stabilizes.
ASTM D1505: Standard test method for density of plastics by the density gradient technique.
ISO 1183: International standard for determining the density of non-cellular plastics.
Proper conditioning of samples at standard temperature and humidity (23°C and 50% RH) is essential before measurement to obtain accurate results.
For critical projects, CloudFilm recommends that buyers request density values measured according to ASTM D1505 or ISO 1183, and that they cross-check supplier data with incoming-goods inspection using the same methods.
CloudFilm’s QA laboratories routinely follow these standards so that the density you see on the datasheet matches the behavior you observe on your packaging lines.
Relationship Between Density and Other Properties
Understanding how density correlates with other properties helps in selecting the right CPP film for specific applications:
Density vs. Barrier Properties: Higher density generally improves moisture barrier properties but may reduce gas permeability resistance in some cases.
Density vs. Mechanical Properties: Films with higher density typically show increased stiffness and tensile strength but may have reduced impact strength.
Density vs. Optical Properties: Optimal density values around 0.90-0.91 g/cm³ provide the best transparency and lowest haze values.
In real projects, it is rarely density alone that decides performance; instead, you balance density with thickness, seal-layer design, anti-fog or anti-static functions and lamination partners.
For a deeper dive into how CPP density interacts with modulus, COF, seal strength and other mechanical/optical parameters, you can refer to our CPP film properties guide.
CPP Film Density Compared With Other Packaging Films
Compared with other common packaging films, CPP’s density around 0.90–0.92 g/cm³ sits in the same family as PP but clearly below PET, nylon and PVDC.
- Versus BOPP film
: BOPP typically has a density around 0.90 g/cm³, very close to CPP, but the biaxial orientation gives higher stiffness at the same micron. CPP offers softer hand-feel and better heat-seal behavior, so you often see BOPP/CPP laminates combining both advantages. - Versus BOPET film
: PET films usually sit around 1.34–1.40 g/cm³. That higher density means higher GSM and lower yield at the same micron, but also much higher stiffness and dimensional stability. PET/CPP is therefore a classic laminate when you need a stiff outer layer plus a sealable CPP inner layer. - Versus PE film
: LDPE/LLDPE are slightly denser (≈0.91–0.93 g/cm³) and softer than CPP. For recyclable mono-PE structures, you may replace CPP with PE seal layers, but you then need to adjust thickness and density to maintain yield and stiffness. - Versus BOPA (nylon) and other high-density films: BOPA sits around 1.12–1.15 g/cm³, with much higher toughness and puncture resistance than CPP. In some applications CPP is combined with BOPA or high-barrier webs to achieve both impact strength and sealability.
For engineers comparing PET/CPP vs mono-PP or hybrid structures, our detailed article on PET vs CPP film explains how density, modulus, heat resistance and sealing all fit together in practical laminates.
FAQs About CPP Film Density
Q1: Why is density important in CPP films?
A: Density affects critical properties including barrier performance, mechanical strength, optical characteristics, and cost efficiency. It’s essential for calculating yield (area per unit weight) and comparing material value between different suppliers.
Q2: How does density differ between CPP and BOPP films?
A: CPP films generally have slightly higher density than BOPP (Biaxially Oriented Polypropylene) films due to differences in molecular orientation and crystallinity. BOPP typically has a density range of 0.88-0.90 g/cm³.
Q3: Can density be modified in CPP films?
A: Yes, manufacturers can adjust density through material selection (homopolymer vs. copolymer), processing conditions (cooling rate), and additive packages. However, significant changes may affect other properties.
Q4: How does temperature affect CPP film density?
A: As temperature increases, CPP films expand, resulting in decreased density. This thermal expansion is reversible when the temperature returns to normal.
Q5: What is the relationship between density and crystallinity in CPP films?
A: Higher density generally indicates higher crystallinity, as the crystalline regions of polypropylene have a more compact molecular structure than amorphous regions.
Q6: How can I quickly estimate GSM and yield for a CPP film if I only know thickness?
A: For a first estimate, you can assume ρ≈0.91 g/cm³ and use GSM ≈ 0.91 × thickness (µm) and yield ≈ 1000 ÷ (0.91 × thickness). This is accurate enough for early costing, but you should still confirm with your CPP supplier’s datasheet and actual samples.
Q7: If I change from 25 µm to 30 µm CPP while keeping density the same, what happens to yield?
A: Yield is inversely proportional to GSM. Going from 25 µm to 30 µm at the same density increases GSM by 20%, so yield (m²/kg) drops by about 16–17%. You will get fewer bags per kilogram but higher strength per bag.
Q8: Does CPP film density affect recyclability?
A: Density itself does not decide recyclability; what matters more is whether your structure is mono-material PP or mixed with PET, PA, PVDC, aluminum foil, etc. However, realistic density data helps recyclers and converters classify materials correctly and design PP-based structures that stay within PP recycling streams.
Q9: How consistent is CPP film density from batch to batch?
A: Reputable producers keep density within a narrow tolerance by controlling resin, additives and process parameters. In practice, the variation is small compared with thickness variation, but for very sensitive applications CloudFilm can discuss tighter density and thickness tolerances as part of the specification.
Q10: What information should I send to CloudFilm if I have specific density or roll-weight targets?
A: Please share your product type, pack format, target thickness, desired roll weight or maximum roll OD, packaging speed and any legal/sustainability constraints. Using this, CloudFilm can recommend CPP density, thickness and structure that meet both technical and logistics requirements.
Industry Applications and Density Considerations
Different applications have specific density requirements:
Food Packaging: General purpose CPP with density around 0.90-0.91 g/cm³ offers optimal balance of strength, clarity, and cost efficiency for food packaging applications.
Metallized Films: Metallized grade CPP requires density around 0.91-0.92 g/cm³ for excellent metal adhesion and barrier properties.
High-Temperature Applications: Retort-grade films maintain stability in the 0.90-0.92 g/cm³ range, ensuring performance under high-temperature sterilization conditions.
Technical Applications: Specialty applications may require precisely controlled density values for specific performance characteristics.
In snacks and coffee, high-barrier metallized CPP often works together with BOPP or PET to deliver long shelf life; in ready-meal pouches, retort-grade CPP gives both heat resistance and strong seals after 121–135°C sterilization.
For tissue, garment and stationery overwraps, lower-thickness general-purpose CPP with well-controlled density provides the right mix of softness, clarity and line efficiency.
If you want to see how CPP density and structure choices map to different market segments (food, personal care, medical, industrial, agriculture), our article on CPP film uses across industries gives many real-world examples.
Practical CPP Film Density Checklist Before Sending An Inquiry
Before you request a CPP film quote, having a short density-focused checklist helps you get a faster and more accurate response.
You can prepare the following information for CloudFilm:
- Product & market: what you are packing (snacks, coffee, retort foods, tissue, garments, stationery, medical devices, industrial parts, etc.).**
- Pack format & line type: pillow packs, overwraps, bags, stand-up pouches; VFFS, HFFS, flow-wrap or pre-made pouch lines.**
- Target thickness & density expectations: typical micron range and whether you have a preferred GSM, yield or roll weight window.**
- Structure idea: mono-CPP, PET/CPP, BOPP/CPP, BOPE/CPP, or other laminates you are considering.**
- Performance priorities: main goals such as shelf life, optics, tear strength, sealing window, machinability or recyclability.**
- Regulatory and certification needs: food-contact regulations, regional standards and any sustainability targets.**
With this checklist, CloudFilm can quickly translate your brief into a concrete CPP density and structure proposal, send targeted samples and help you move from trial to mass production with fewer iterations.
About CloudFilm
At CloudFilm, we recognize that precision in properties like density is what sets high-performance packaging apart.
Our advanced CPP films are engineered to exact density specifications, ensuring optimal performance in your specific applications—whether you need superior clarity for premium product visibility, enhanced barrier properties for extended shelf life, or exceptional machinability for high-speed packaging lines.
With CloudFilm, you get more than just materials; you get solutions tailored to your technical requirements and sustainability goals. Partner with us to elevate your packaging innovation with films that deliver consistency, quality, and value.
By combining stable density control, modern cast-film lines and strong export experience, CloudFilm supports customers in more than 30 countries with CPP and other flexible films that are ready for today’s performance and tomorrow’s recycling targets.
