Premium Herb Packaging | Mylar Bags & Aluminum Film

Material Composition

Inner Layer

Material Selection: Food-grade Low-Density Polyethylene (LDPE) or Polypropylene (PP), with a thickness range of 20-50 micrometers (μm).

Safety Standards: Compliant with FDA 21 CFR 177.1520 (for polyethylene) or 177.1630 (for polypropylene) certification, heavy metal content ＜1ppm, and no phthalates detected (SGS report threshold: 0.1ppm).

Sealing Performance: Heat sealing temperature is set at 120-180℃, pressure at 0.3-0.5MPa, and seal strength ≥4N/15mm (tested by ASTM F88-15 method).

Special Treatment: Medical-grade products are added with antibacterial coatings (e.g., silver ions) to inhibit mold growth, suitable for environments with humidity ＞80%.

Middle Layer

Aluminum Foil Solution: Soft aluminum with a purity of over 99.5% and a thickness of 7-12μm, with water vapor transmission rate (WVTR) approaching 0 and oxygen transmission rate (OTR) ＜0.001cm³/(m²·24h).

Aluminum-Plated PET Alternative: A 12μm-thick PET substrate with a vacuum-deposited aluminum layer (0.02-0.05μm thick), reducing costs by 40%, with OTR ＜0.1cm³/(m²·24h) and WVTR ＜0.05g/(m²·24h).

UV Shielding: The aluminum layer has a reflectivity of ＞99% for UV-A/UV-B (tested by ASTM G154). Experiments show that at 25℃ under light, the attenuation rate of THC inside the bag is reduced by 98%.

Anti-Static Version: Added carbon nanotube coating (surface resistance 10⁶-10⁹Ω) to avoid contamination of concentrates due to electrostatic adsorption.

Outer Layer

Substrate Types:

PET film: Thickness 25-75μm, light transmittance ＞88%, tensile strength ≥200MPa (ISO 527-3 standard);

BOPP film: Thickness 20-50μm, coefficient of friction 0.2-0.4μ (ASTM D1894), suitable for high-speed printing production lines.

Printing Processes:

Gravure printing: 8-12 color groups, resolution 1200dpi, color difference ΔE ＜1.5 (ISO 12647-2);

Digital printing: Supports variable data (e.g., batch numbers, QR codes), with a minimum font size of 1pt that is clearly legible.

Surface Treatment:

Matte coating: Reduces reflection and improves tactile texture (Ra roughness 1.5-2.0μm);

Local UV embossing: The thickness of gold/silver stamping areas increases by 20-30μm, enhancing three-dimensionality.

Core Advantages

Oxygen, Moisture and Light Barrier

THC and CBD in Herb are sensitive to oxygen, moisture and light, and the three-layer structure of Mylar bags acts like a triple lock for these components.

• Oxygen Barrier: The oxygen transmission rate (OTR) of the middle aluminum film layer is ＜0.5cm³/(m²·24h) (tested by ASTM D3985 method). Compared with ordinary plastic bags (100-500cm³) and kraft paper bags (300-800cm³), the gap is more than 200 times. A 2023 experiment by the University of California, Davis: For the same 7g of Herb flower, stored in a Mylar bag for 6 months, THC remains at 95%; while in ordinary bags, only 60-70% remains.
• Moisture Barrier: Water vapor transmission rate (WVTR) ＜0.1g/(m²·24h) (ASTM E96). During the rainy season in Florida (90% humidity), the humidity inside the bag can be stabilized below 55% (ideal storage humidity). Ordinary plastic bags have a WVTR of 5-15g, and they become damp and moldy after 1 month of storage.
• Light Barrier: The aluminum film reflects 99% of ultraviolet rays (ASTM G154), even blocking UVA (long-wave). A test by Oregon State University: At 25℃ under light, the retention rate of flavor substances in Herb flower in Mylar bags is 80% higher than that in transparent bags after 6 months.

Durability and Toughness

• Tensile Strength: The outer PET film has a tensile strength of 200-300MPa (ISO 527-3), equivalent to withstanding 2-3 tons of tension per square centimeter. A simulation test by the Herb Commerce and Transportation Association (CCTA) in the US: Dropped from 1m height 3 times, the bag body has no tears; ordinary plastic bags break after 1 drop.
• Puncture Resistance: The multi-layer composite structure (PE + aluminum film + PET) can withstand puncture by a 1.5mm sharp needle (ASTM D1709). Feedback from Canada’s Tweed brand: For 1lb wholesale bags, when stacked and pressed against the corner of metal shelves, there is no leakage of goods.
• Temperature Resistance Range: No deformation from -70℃ to 150℃ (ASTM D746 low-temperature test, D648 heat deflection test). Stored in cold chain transportation (-20℃) or summer truck compartments (60℃) for 3 days, the bag body remains neither brittle nor soft.
• Anti-Aging: Stored in an environment of 85℃/85% humidity for 7 days (ISTA 2A aging test), dimensional change ＜0.5%; ordinary plastic bags shrink by more than 5%, and printed patterns fall off.

Sealing Performance

• Heat-Sealed Edge: The inner PE layer is melted and bonded when heated to 120-180℃, with seal strength ≥4N/15mm (ASTM F88-15). Under a microscope, the sealed edge has no gaps (pore size ＜50μm), and it does not leak even when filled with liquid concentrates.
• Self-Adhesive Strip + CR Certification: The outer layer is added with a press-type self-adhesive strip (opening force 10-15N), and it also complies with the ASTM D3475 child-resistant standard (opening force for children ＞15N). Field test in California pharmacies: Adults can open it with one hand in 3 seconds, while 5-year-old children cannot open it after 100 attempts.
• Easy-Tear Notch + Exhaust Valve: Retail bags are added with serrated easy-tear notches (tearing force 2-3N), and fermented products (e.g., kief) are equipped with one-way exhaust valves (aperture 0.2mm), allowing gas to escape only and preventing bulging and rupture.

Safety and Compliance

• Food Safety: The inner PE/PP complies with FDA 21 CFR 177.1520/1630 certification, with heavy metals (lead, cadmium) ＜1ppm and no phthalates detected (SGS report threshold: 0.1ppm).
• Child Resistance: Optional thickened self-adhesive strips (opening force ＞20N) to meet the laws of Colorado and Washington states (requiring CR packaging with opening force ＞18N).
• Environmental Label: If recycled PET (rPET) is used, GRS (Global Recycled Standard) certification can be provided, which is favored by European brands (e.g., Seed City in the Netherlands).

Application Scenarios

Whole Flower and Trim

Whole flower (unprocessed flower buds) and trim account for 60% of European and American Herb retail volume (Grand View Research 2024). Mylar bags are divided into two categories by specification:

• Retail Small Bags: 3.5g (1/8 oz) and 7g (1/4 oz) zip-top bags are dominant, accounting for 45% of the market share in this scenario (Leafly 2024).
  • Structure: Inner PE (25μm) for sealing, middle aluminum-plated PET (0.03μm aluminum layer), outer PET (30μm) for printing brand logos.
  • Performance: WVTR ＜0.1g/(m²·24h). When 7g of flower is stored in an environment of 25℃/60%RH, the humidity remains stable at 55%-58% for 30 days (field test by Harborside Farms in California).
  • Design: Added serrated easy-tear notch (tearing force 2.5N), with a transparent window (15% of the total area) on the bag body for easy viewing of flower quality.
• Wholesale Large Bags: 1oz (28g) and 1lb (454g) flat bags, accounting for 30% of the market share, used for farm warehousing and dealer transit.
  • Structure: Inner PP (35μm, resistant to stacking and extrusion), middle pure aluminum foil (9μm, OTR ＜0.001cm³), outer BOPP (50μm, wear-resistant).
  • Load-Bearing Capacity: Stacked 5 layers high from 1m (total weight 25kg), no rupture at the bag bottom (ASTM D642 test); no damage after 3 hours of transportation vibration test (ISTA 3A).

Pre-Rolled Products

Pre-rolled Herb (joints, blunts) need to avoid moisture absorption from the mixture of tobacco and Herb. Mylar bags adopt a long strip shape with a built-in moisture-proof layer:

• Size: 15×5cm (suitable for standard pre-roll lengths of 70-110mm), thickness 40μm (three-layer composite).
• Moisture-Proof Measures: A silica gel moisture-absorbent cotton sheet is attached to the inner layer (water absorption capacity 0.5g/sheet, tested by ASTM F1249). After loading 2 pre-rolls, the humidity inside the bag increases by ＜2% within 24 hours (field test in Florida).
• Brand Case: Raw Garden in the US adopts this design, and in 2023, 89% of users reported that “tobacco does not clump after pre-rolls are stored for 1 month” (questionnaire on the brand’s official website).
• Special Version: Party sharing bags (30×8cm) with easy-tear dotted lines (tearing force 3N), which can be split into 3 small 5g bags, accounting for 12% of the pre-roll packaging market.

Concentrates

Concentrates such as wax, oil, and capsules have high concentrations of active ingredients. Mylar bags use an “aluminum foil liner + small bag structure”:

• Specifications: 8×6cm bags for 1g wax/oil, 6×4cm bags for 0.5g capsules, accounting for 70% of concentrate packaging (Health Canada 2023 data).
• Enhanced Barrier: Inner aluminum foil (7μm, WVTR ＜0.01g/(m²·24h)), outer Mylar (25μm PET), OTR ＜0.05cm³ (90% lower than ordinary Mylar bags).
• Leak-Proof Design: Heat-sealed edge width 8mm (5mm for ordinary bags), seal strength ≥5N/15mm (ASTM F88-15). No leakage when filled with liquid oil and inverted for 24 hours (Tweed brand test).
• Case: For Tweed’s 1g wax bags in Canada, 91% of users reported that “remaining wax has no volatilization after opening and storing for 2 weeks” (Leafly 2024).

Seeds and Tools

Mylar bags use mini sizes with high tensile strength:

• Size: 5×3cm seed bags (holding 10-20 seeds), 10×7cm tool bags (holding small grinders).
• Performance: Tensile strength 250MPa (ISO 527-3), no holes when punctured with a 1.5mm sharp needle (ASTM D1709); OTR ＜0.5cm³, seed germination rate remains above 85% after 1 year of storage (Seed Supreme data in the Netherlands).
• Marking: The outer layer is printed with strain names (2pt font, clearly legible), germination rates (e.g., “92% Germination”), and batch numbers are laser-engraved (depth 0.1mm, non-erasable).

Medical Herb

Medical Herb requires precise dosing. Mylar bags are added with dosage markings and child resistance:

• Design: The bag body is printed with a single dose (e.g., “5mg THC/bag”), and uses an ASTM D3475 CR-certified self-adhesive strip (opening force 18N, cannot be opened by children).
• Case: Canopy Growth’s 7g bags, a California medical brand, are printed with “1 bag per day (containing 35mg THC)”, and with doctor’s prescriptions, patient compliance has increased by 25% (brand’s 2023 clinical feedback).
• Special Version: Capsule-specific bags (10×6cm) with 3 inner compartments (holding 1 capsule each) to prevent confusion, accounting for 15% of medical packaging.

Aluminum Film

Aluminum film is the mainstream material for high-end Herb packaging in the United States and Canada. With its ultimate barrier properties of oxygen transmission rate ≤0.05 cc/m²·24h and water vapor transmission rate ≤0.01 g/m²·24h, it isolates oxygen, moisture, and 99% of ultraviolet rays.

65% of Mylar bags in the North American market use aluminum-plated film (VMPET/VMCPP). Its 7-12μm aluminum layer increases the puncture resistance of the packaging by 250%, reduces the transportation damage rate from 15% to 5%, and extends the product shelf life to 3 times that of ordinary packaging (e.g., Herb flower from 30 days to 90 days), while complying with the FDA 21 CFR 175.105 food contact standard.

Basic Characteristics

Oxygen Barrier

The oxygen barrier capacity of aluminum film is measured by Oxygen Transmission Rate (OTR), in units of cc/m²·24h (cubic centimeters of oxygen transmitted per square meter per day).

• Pure Aluminum Foil (9μm thick): OTR ≤0.001 cc/m²·24h (Intertek 2023 test), equivalent to blocking oxygen outside, almost impermeable.
• Aluminum-Plated Film (VMPET, 12μm substrate + 30nm aluminum layer): OTR ≤0.05 cc/m²·24h (SGS report), 1/10 of PVDC film (0.5 cc) and 1/1000 of LDPE film (50 cc).

  By comparison: The OTR of ordinary PE packaging is 50, meaning the oxygen concentration inside the packaging will rise from 21% to 23% after 30 days, while the oxygen concentration in aluminum film packaging remains below 21.01% after 30 days. A 2023 experiment by Colorado State University showed that THC retention rate of Herb flower sealed with aluminum film is 92% after 60 days, while only 65% remains in PE packaging.

Water Vapor Transmission

Herb is sensitive to both moisture and dryness —— mold grows easily when humidity exceeds 65%, and flowers and leaves become brittle when below 40%. The Water Vapor Transmission Rate (WVTR) of aluminum film is in units of g/m²·24h (grams of water transmitted per square meter per day).

• Pure Aluminum Foil: WVTR ≈0 (measured ＜0.001 g), completely impermeable to moisture.
• Aluminum-Plated Film (VMCPP, 20μm substrate + 40nm aluminum layer): WVTR ≤0.01 g/m²·24h (tested by ASTM E96 standard), 1/100 of PP film (1 g) and 1/300 of PE film (3 g).

  Practical scenario: Stored in a high-humidity warehouse (35℃/80%RH) for 30 days, the humidity inside aluminum film packaging rises from 55% to 58%, while that in ordinary paper bags soars from 55% to 75% (the critical value for mold growth). Feedback from growers in British Columbia, Canada: After using aluminum film bags, the amount of flowers and leaves scrapped due to moisture absorption has decreased by 70%.

UV Barrier

Ultraviolet rays (200-400nm) decompose chlorophyll and terpenes in Herb. The UV barrier rate of aluminum film is measured by a spectrophotometer, with a result of ＞99%.

• Pure Aluminum Foil: Completely opaque, with a barrier rate of 100% (theoretically).
• Aluminum-Plated Film: Visible light transmittance ＜5%, UV transmittance ＜1% (ASTM D1003 test).

  Comparison: Transparent PET film has a UV barrier rate of only 10%, and colored HDPE bags about 50%. A study by the University of California, Davis found that after 7 days of light exposure, the retention rate of β-caryophyllene (anti-inflammatory terpene) in Herb flower in aluminum film packaging is 89%, while only 30% remains in transparent bags.

Physical Strength

• Tensile Strength (ASTM D882): Pure aluminum foil (9μm) has a longitudinal strength ≥120MPa and a transverse strength ≥110MPa; aluminum-plated PET (12μm) has a longitudinal strength ≥200MPa (strength contributed by the plastic substrate). The tensile strength of ordinary PE film is only 20-30MPa.
• Folding Endurance (ASTM D2176): Aluminum-plated PET cracks only after 500 repeated folds, while PE film breaks after 50 folds.
• Puncture Resistance (ASTM F1306): A 1.3mm steel needle requires 15N of force to pierce pure aluminum foil (9μm); PE film is pierced with only 3N of force. In North American transportation tests, the damage rate of aluminum film Mylar bags is 5%, compared with 15% for ordinary plastic bags (ISTA 3A vibration standard).

Safety

Regulatory Basis: FDA 21 CFR 175.105 (indirect food contact), EU 10/2011 (plastic food contact materials), allowing use in packaging oil-containing and water-containing products.

Testing Items: Heavy metals (lead ＜0.01mg/kg, cadmium ＜0.005mg/kg), total migration (＜10mg/dm²), potassium permanganate consumption (＜10mg/kg).

No Additives: Both pure aluminum foil and aluminum-plated film do not contain BPA or phthalates (plasticizers). The aluminum-plated layer is made by vacuum evaporation (non-chemical coating) to avoid solvent residues. SGS random inspections show that the migration amount of commercially available aluminum film packaging is all ＜1mg/dm², far below the limit value.

Application Scenarios

Retail Flower and Trim

90% of retail Herb flower and trim are packaged in aluminum film Mylar stand-up pouches (source: PMMI 2023 Herb Packaging Report).

This type of pouch has a structure of “PET printing layer + aluminum-plated PET (VMPET) + PE heat-sealing layer”, with a 12μm-thick aluminum-plated layer (30nm aluminum layer), OTR ≤0.05 cc/m²·24h, and WVTR ≤0.01 g/m²·24h.

• Why Stand-Up Pouches? It has a rigid bottom gusset that allows it to stand on shelves, making it 30% more noticeable than flat bags (retailer visual test). The pouch mouth is equipped with an easy-tear line and a resealable zipper lock, allowing consumers to press it back to prevent moisture after opening, with a repurchase rate 18% higher than non-sealable bags (2023 retail data from Quebec, Canada).
• Role of Aluminum Film: A 2022 experiment by Oregon State University: After 60 days of storage, Herb flower in aluminum film bags retains 92% THC and 89% β-caryophyllene (aromatic terpene); while in ordinary paper bags, only 65% THC and 52% aroma remain. The morphology of flowers and leaves is also more intact —— the aluminum film has a puncture resistance of 250N (ASTM F1306 test), making it less likely to break due to stacking and extrusion during transportation, reducing the damage rate from 15% (ordinary bags) to 5% (ISTA 3A vibration test).

Concentrated Extracts

High-concentration extracts such as wax, oil, and hash are sensitive to oxidation, light, and leakage, and are often packaged in blister packaging + aluminum-plastic lidding material.

The blister is a PVC or PETG plastic shell with individual cavities for extracts, covered with a piece of aluminum foil lidding material (20μm pure aluminum foil or 15μm aluminum-plated film).

• Aluminum Lidding Material Parameters: Pure aluminum foil lidding material has an OTR ≤0.001 cc/m²·24h (Intertek test), completely blocking oxygen; aluminum-plated film lidding material costs 30% less, with an OTR ≤0.03 cc/m²·24h, suitable for short-term storage (within 3 months). The edges of the lidding material are pressed and sealed by a heat sealer, with seal strength ≥3N/15mm (ASTM F88 standard), no liquid leakage when inverted and shaken.
• Effectiveness Data: A California brand uses aluminum lidding material blisters to package THC oil (85% concentration), maintaining 90% efficacy after 12 months; the same product with plastic lidding material drops to 75% efficacy after 6 months. Blisters also allow single-dose separation, enabling consumers to take one at a time and avoid repeated opening and moisture absorption (especially suitable for travel scenarios).

Edible Dosage Forms

Edible dosage forms such as gummies, lozenges, and capsules use aluminum-plastic composite hoses or aluminum tubes.

The hose structure is “PE inner layer + 15μm aluminum foil barrier layer + PP outer layer”, with the aluminum foil as the middle layer, which is both soft and strong;

Aluminum tubes are made entirely of aluminum (0.2mm wall thickness), with lids designed for child resistance (requiring simultaneous pressing and rotation to open).

• Hose Advantages: Easy to squeeze and use, the aluminum foil layer ensures WVTR ≤0.01 g/m²·24h. When gummies are stored in an environment of 35℃/80%RH for 30 days, the water content only decreases by 2% (ordinary plastic tubes decrease by 8%, becoming hard). 60% of THC gummies in the North American market use this type of hose (Grand View Research 2023 data).
• Aluminum Tube Scenarios: High-end CBD capsules use all-aluminum tubes with a wall thickness of 0.2mm, compressive strength ≥200kg (no deformation when stacked 10 layers high), and 100% UV barrier rate. A desiccant packet is placed inside the tube (replace when the humidity indicator card turns blue), with a shelf life of up to 2 years (1 year for ordinary plastic bottles).

Compliance and Sustainability

Compliance Requirements

From Child Resistance to Heavy Metal Limits

The most basic requirement of US state regulations on Herb packaging is the ASTM D3475 Child-Resistant Packaging Standard —— requiring packaging to be “impossible for 5-year-old children to open within 5 minutes, while easily openable by adults”.

In 2023, random inspections by the California Department of Public Health showed that products using aluminum film Mylar bags had a child accidental opening complaint rate of 0.3%, compared with 5% for ordinary plastic bags.

Another requirement is California Prop 65, which limits the migration of heavy metals such as lead and cadmium in packaging: lead ＜0.01mg/kg, cadmium ＜0.005mg/kg.

Aluminum film (pure aluminum or aluminum-plated) itself has low heavy metal content. SGS 2023 random inspections show that the migration amount of commercially available aluminum film packaging is all ＜0.005mg/kg, far below the limit value. In contrast, cases of recall due to 3 times excessive migration amount of some inferior plastic packaging occur from time to time.

At the federal level, FDA 21 CFR 175.105 stipulates that aluminum film must pass the “indirect food contact test”, including total migration (＜10mg/dm²) and potassium permanganate consumption (＜10mg/kg), to ensure the safety of extract contact.

Health Canada’s Packaging Rules

Chapter 8 of Canada’s Herb Regulations clearly states: Packaging must be “tamper-evident, oxygen and light barrier, and clearly labeled”.

Aluminum film has become the preferred choice for compliance due to its OTR ≤0.05 cc/m²·24h and UV barrier rate ＞99%. In 2022, Health Canada announced that 90% of product recall cases due to insufficient packaging barrier properties used non-aluminum film materials.

In terms of labeling, the surface layer of aluminum film (PET/BOPP) can print high-resolution patterns, meeting the font size (minimum 6pt) and contrast requirements of the CGSB-43.147 standard, avoiding being judged non-compliant due to blurred labels.

Sustainability

Production Side

Pure aluminum foil production consumes high energy (about 16,000 kWh/ton of aluminum, International Aluminum Institute 2023), 3 times higher than plastic film.

To address this, North American manufacturers promote aluminum-plated film as a substitute for pure aluminum foil: The thickness of the aluminum-plated layer is reduced from 50nm (early stage) to 30nm (VMPET), reducing aluminum usage by 40%, with only a 10% reduction in barrier properties (OTR increased from 0.03 to 0.05 cc/m²·24h) and a 25% cost reduction.

Another direction is bio-based aluminum-plated film, using plant-based polyester (e.g., corn starch-based PET) instead of petroleum-based plastic.

Canada’s Canopy Growth piloted this film in 2023, with a carbon footprint 20% lower than traditional aluminum-plated film (life cycle assessment LCA data), but the cost is 1.8 times that of traditional film, currently only used for high-end lines.

Recycling Side

The recycling rate of aluminum film in North America is about 35% (Aluminum Association 2023), among which the recycling rate of pure aluminum foil is 95% (remelted and rerolled). Due to the plastic layer in aluminum-plated film, recycling is difficult —— traditional recycling plants often classify it as “non-recyclable film”, and mixing it in affects the purity of the entire batch of plastic recycling.

To solve this problem, the industry promotes film-specific recycling programs:

• How2Recycle Label: Requires packaging to be labeled “Aluminum-plastic composite film, put into film recycling bins”. The number of participating brands increased from 50 to 120 in 2023.
• Community Pilots: Denver, Colorado has set up “Herb packaging recycling points”. Aluminum-plated film is collected separately and sent to special equipment to separate the aluminum layer (60% recycling rate), and the plastic layer is made into pallets.

Comparative data: The recycling rate of ordinary plastic packaging is only 9% (EPA 2023). Even with plastic, aluminum film has higher comprehensive recycling value —— 1 ton of aluminum-plated film can produce 0.3 tons of aluminum ingots (valued at $600) and 0.5 tons of recycled plastic (valued at $200) after recycling, saving $150/ton in landfill fees compared with direct landfilling.