Slow Thaw Dry Ice Packs – Extend Cold Chain Shipping to 72 Horas

When you need to keep food, medicines or biologics frozen for days, traditional dry ice or gel packs alone often fall short. Slow thaw dry ice packs blend solid carbondioxide (gelo seco) with phasechange gel materials to maintain ultracold temperatures for até 72 horas, outlasting ordinary dry ice’s typical 18–24hour window. By slowing the sublimation of CO₂ and providing a buffer against sudden temperature spikes, these hybrid packs extend cooling time while reducing the amount of dry ice needed. This comprehensive guide explains how slow thaw dry ice packs work, when to choose them, how to pack them safely and what trends are shaping their future in 2025.

What makes a slow thaw dry ice pack different from traditional dry ice or gel packs?

When should you choose slow thaw dry ice packs over gel packs or pure dry ice?

How do you calculate dry ice and gel quantities for different container sizes?

What safety and regulatory rules govern the use of hybrid dry ice packs?

What innovations and market trends will impact slow thaw dry ice packs in 2025?

What Is a Slow Thaw Dry Ice Pack and How Does It Work?

A slow thaw dry ice pack is a hybrid cooling solution that combines the intense cold of dry ice with the steady cooling of gel packs or phasechange materials (PCMs). Dry ice is solid carbondioxide that sublimates directly into gas, delivering temperatures around –78 °C but lasting only 18–24 hours for every 2.5 kg used. By encasing dry ice pellets or sheets in gel or PCM layers, the hybrid pack slows sublimation and moderates the temperature rise. Gel packs freeze at 0 °C and thaw slowly; advanced PCM sheets hold –12 °C to –18 °C for 48 hours and can be reused over 30 ciclos

. The combined effect is steady subzero temperatures up to 72 horas, reduced CO₂ release and protection for sensitive goods.

Components of a Slow Thaw Dry Ice Pack

A typical slow thaw dry ice pack includes a layer of vacuuminsulated panels (VIPs) or thick foam to slow heat transfer, a sealed dry ice core and an outer layer of gel or PCM packs. Como o gelo seco sublima, the gel absorbs some of the cold energy, releasing it gradually instead of all at once. This design prevents the rapid temperature spike that pure dry ice can cause when packed directly against products. It also reduces condensation because the gas escapes before moisture forms.

When Should You Choose a Slow Thaw Dry Ice Pack?

Selecting between traditional dry ice, gel packs or a hybrid pack depends on the temperature requirements, shipment duration and regulatory constraints for your cargo.

Frozen foods and meal kits: For meats, seafood or prepared meals, keeping temperatures below –20 °C is essential. Traditional dry ice provides ultracold conditions but sublimes quickly. Slow thaw dry ice packs offer steady subzero temperatures for 24–48 hours; when layered with PCM gel sheets they can maintain cold for 48–72 hours. If your shipment will travel longer than three days or through extreme heat, combining slow thaw packs with extra gel or VIP insulation is recommended.

Pharmaceuticals and biologics: Biopharmaceuticals often require temperatures below –60 °C. Sealed CO₂ cells and cryogenic gels in hybrid packs can maintain –60 °C to –40 °C for up to 48 hours without hazardousmaterials fees. For vaccines needing 2–8 °C, gel packs alone may suffice; but to keep –12 °C to –18 °C for 48 horas, pairing dry ice with PCM gel sheets offers flexibility.

Ecommerce groceries and meal kits: Online grocery services must keep produce around 0–5 °C. Gel packs freeze quickly and thaw slowly, making them ideal for keeping vegetables fresh for 24–48 hours. When mixed orders include frozen items like ice cream, a slow thaw dry ice pack with a gel layer creates separate temperature zones, keeping ice cream hard while vegetables stay chilled.

Laboratory samples and life sciences: Cell cultures, plasma and blood require –70 °C or colder. Encasing dry ice in a slow thaw pack reduces handling risks and extends hold time; the gel cushions vials and provides an intermediate temperature buffer. Hybrid packs can be reused multiple times, cutting waste and ensuring compliance with laboratory safety protocols.

Consumer deliveries and outdoor adventures: For subscription meat boxes or camping trips, slow thaw packs offer longlasting cold without requiring special gloves or vented storage. They can keep items frozen for 48 hours or longer, making them userfriendly for campers and road trips.

Packing Best Practices for Slow Thaw Dry Ice Packs

Proper packing maximizes the performance of hybrid packs. Follow these guidelines to maintain consistent cooling and comply with safety regulations.

Use a highquality insulated container: Painéis isolados a vácuo (VIPs) or thick foam reduce thermal loss. VIPs are up to five times more efficient than conventional foam.

Prechill the container: Precool your shipping box by placing gel packs inside for at least an hour before loading. Starting with a cold vessel extends the cooling period.

Ventive o contêiner: Never seal dry ice in an airtight box. Always include vent holes or a loosefitting lid to allow CO₂ gas to escape and prevent pressure buildup. Vented packaging is also required for air travel.

Etiqueta claramente: Mark the package with “Dry Ice” or “Carbon Dioxide, solid” and state the net weight of CO₂. Even hybrid packs must be labeled when they contain sealed dry ice cells.

Calculate refrigerant quantity: As a rule of thumb, usar cerca de 2.5 kg of dry ice per 24 horas de tempo de envio. Hybrid packs slow sublimation, so less CO₂ may be required. Em caso de dúvida, err on the side of more refrigerant and insulation.

Estimated Dry Ice and Hybrid Sheet Requirements

Use this table as a starting point, adjusting for environmental temperature, insulation thickness and product thermal mass. Always prechill the container and monitor internal temperature to verify performance.

Packing Strategy

Hydrate and freeze sheets correctly: Some dry ice pack sheets require hydration. Soak the sheet in cold water for 3–5 minutes to let the cells absorb water, then freeze flat at –20 °C or colder for at least 24 horas.

Strategic placement: Position hybrid packs around the product rather than only on the bottom. Pair sensitive goods with bubble wrap or padded inserts to prevent damage.

Monitorar temperatura: Include an NFC or Bluetooth temperature logger inside the package to track deviations and provide traceability. Smart sensors are becoming standard in 2025

Safety Gear and Handling

Always treat dry ice and hybrid packs with respect. Wear insulated gloves and safety goggles when handling to avoid frostbite. Avoid storing dry ice in sealed refrigerators; CO₂ gas can displace oxygen and build up in confined spaces. After unpacking, salvage unused dry ice or packs with tongs and place them in a ventilated cooler for reuse within two to three days. Do not refreeze sublimated dry ice; once it’s gone, it cannot be regenerated. Donate excess dry ice to a local lab or restaurant to minimize waste.

Safety Considerations and Regulatory Compliance

While hybrid packs mitigate some risks, handling any form of dry ice requires compliance with safety and transportation regulations. Dry ice causes severe frostbite on contact and can reach –60 °C even when encased in gel. CO₂ gas is heavier than air and can accumulate in poorly ventilated spaces. Follow these guidelines:

Ventilation requirements: International shipping regulations require proper ventilation for dry ice to release CO₂ gas. Ensure your container has vent holes or micropores; carriers may refuse packages that do not comply.

Labeling and documentation: O gelo seco é classificado como um Aula 9 hazardous material under UN 1845. Shipments on passenger aircraft are limited to 2.5 kg por pacote and must be vented and labeled. Hybrid packs with less than 2.5 kg of CO₂ may be exempt from some hazardous labeling requirements, but always confirm with your carrier. The package must display “Dry Ice” or “Carbon Dioxide, solid” and the net weight.

Frostbite and CO₂ exposure: Even though the CO₂ is sealed, the outer surface can be extremely cold. Use cryogenic gloves and goggles when packing and unpacking. Never store hybrid packs in sealed rooms or home refrigerators; CO₂ gas can accumulate.

Disposal and environmental impact: Gel pack components are often biodegradable and can be refrozen dozens of times. Once dry ice has sublimated completely, you cannot reconstitute it; dispose of leftover gel packs or PCM responsibly. Choose suppliers who capture CO₂ from renewable sources like ethanol fermentation.

Cost and Sustainability Considerations

Switching to slow thaw dry ice packs involves upfront investment but yields longterm benefits for budgets and the environment.

Lower packaging costs over time: Although dry ice is inexpensive per kilogram, hazardousmaterials fees, training costs and singleuse packaging drive up expenses. Hybrid packs can be reused over 30 ciclos, reducing packaging spend by up to 75 %. Because gel packs maintain steady temperatures, you can use smaller quantities of dry ice, cutting raw material costs. In a case study from Los Angeles, a dessert company switched from loose dry ice pellets to slow thaw pack sheets; transit times extended from 36 para 60 horas, CO₂ consumption dropped by 20 % and customer complaints about freezer burn nearly disappeared.

Improved product quality and customer satisfaction: Hybrid packs minimize temperature swings that damage products. Controlled sublimation prevents freezer burn and preserves efficacy for vaccines and biologics. Better product quality reduces returns and fosters customer loyalty, offsetting the higher upfront cost.

Sustainability and carbon footprint: Hybrid packs use less CO₂ overall by combining dry ice with phasechange gels. Many gels are biodegradable or recyclable, reduzindo o impacto ambiental. Manufacturers are also sourcing CO₂ from biobased feedstocks, lowering greenhousegas emissions. By extending hold times, hybrid packs reduce the number of shipments and the need for energyintensive refrigeration, cutting your carbon footprint.

2025 Trends and Innovations in Slow Thaw Dry Ice Packs

A indústria da cadeia fria está evoluindo rapidamente. Por 2025 several innovations are reshaping how slow thaw dry ice packs are designed and used, improving performance, sustainability and regulatory compliance

Visão geral das tendências

Hybrid and multizone packaging: Combining dry ice and PCM materials in a single pack creates multiple temperature zones, allowing one shipment to carry both frozen and refrigerated products

Advanced gel sheets: New gel sheets hold –12 °C to –18 °C for up to 48 hours and can be reused over 30 ciclos, making them a costeffective alternative to pure dry ice

Sensores inteligentes: Integration of NFC or Bluetooth temperature loggers provides realtime monitoring and alerts for temperature excursions

Materiais ecológicos: Manufacturers are developing biodegradable insulation and PCM materials to reduce waste and pollution

• . CO₂ used in dry ice production is increasingly captured from renewable sources

Regulatory updates: The Food Safety Modernization Act (FSMA) and other regulations push shippers to adopt solutions that reduce hazards and ensure traceability

Últimos desenvolvimentos de vista

CO₂ supply challenges: Dry ice demand is growing about 5 % per year while CO₂ supply increases only 0.5 %, leading to price surges of up to 30 % em 2024. Hybrid packs help mitigate shortages

Nonhazardous classification: Some hybrid replacement packs encase CO₂ in sealed cells, limiting its release and exempting them from Class 9 rotulagem

Reusable pack sheets: Modern dry ice pack sheets with flexible cells deliver –40 to –20 °C for 36–48 hours and are reusable

Market growth: The global cold chain logistics market is projected to expand from US$268.5 billion in 2023 to US$647.47 billion by 2028 at a compound annual growth rate of 15.1 %

• . Rising demand for perishable foods and pharmaceuticals is fueling innovation in packaging

Insights de mercado

The rise of ecommerce, meal kits and biologics has fueled demand for reliable coldchain solutions. Consumers expect fresh groceries and medications delivered safely, and businesses want to reduce spoilage and regulatory risks. Slow thaw dry ice packs support these trends by providing extended cooling, reducing CO₂ use and improving sustainability. They also help companies meet FSMA requirements for temperature monitoring and record keeping.

Perguntas frequentes

Q1: How long does a slow thaw dry ice pack last? A hybrid pack can maintain subzero temperatures for 36–72 horas, depending on the quantity of CO₂ and PCM used. This is longer than traditional dry ice alone, which typically lasts 18–24 hours for 2.5 kg. Prechilling your container and using good insulation extend the cooling duration.

Q2: Is a slow thaw dry ice pack safe for shipping food? Sim. Encasing dry ice in sealed cells and surrounding it with gel reduces frostbite risk and prevents direct contact with products. Because the CO₂ sublimates directly to gas, no water residue remains to damage packaging. Always provide ventilation and label the package properly.

Q3: Can I reuse a slow thaw dry ice pack? Many hybrid packs are designed for reuse. Highquality gel sheets can be refrozen over 30 ciclos with less than 10 % capacity loss. Dry ice cannot be refrozen once sublimated, but you can reuse the flexible pack and refill it with new CO₂.

Q4: What’s the difference between a gel pack and a slow thaw dry ice pack? Gel packs freeze quickly and thaw slowly, maintaining temperatures near 0 °C. They are ideal for keeping products at 2–8 °C and do not require hazardousmaterials labeling. A hybrid pack combines a gel pack with dry ice to achieve lower temperatures (< –20 °C) and longer durations.

Q5: How do I dispose of leftover CO₂ and gel after my shipment arrives? Let leftover dry ice sublimate outdoors or in a ventilated area; never throw it in the trash. Gel packs can often be reused or emptied into general waste if they are nontoxic. If the pack contains specialized PCM, follow your supplier’s disposal guidelines. Donating leftover CO₂ to a local lab or restaurant is a sustainable option.

Q6: Are slow thaw dry ice packs allowed on airplanes? On passenger flights, the TSA and FAA allow you to bring até 2.5 kg (5.5 Libra) of dry ice per passenger in carryon or checked baggage, provided the container is vented and clearly labeled. Cargo shipments follow IATA Dangerous Goods Regulations, requiring Class 9 hazard labels and waybill entries. Gel packs alone are not subject to these limits.

Dicas e conselhos práticos

Choose the right pack for the job: Use gel packs for shipments under 24 hours or products needing 2–8 °C. For longer trips or temperatures below –20 °C, select hybrid slow thaw packs.

Consider your environmental impact: Opt for suppliers that offer reusable gel sheets and source CO₂ from renewable feedstocks. Reusing hybrid packs up to 30 times reduces both waste and cost.

Implement smart monitoring: Use NFC or Bluetooth temperature sensors in your shipments to log realtime data and react quickly to deviations

• . This data can help improve packaging methods and comply with FSMA recordkeeping requirements.

Educate your team: Train staff on proper handling—wear gloves, pacotes de ventilação, label correctly and follow disposal rules. Good training reduces accidents and regulatory penalties.

Exemplo do mundo real: A dessert company in Los Angeles switched from loose dry ice pellets to slow thaw hybrid packs with PCM gels. Transit times increased from 36 horas para 60 horas, CO₂ consumption dropped by 20 % and customer complaints about freezer burn nearly disappeared. The company also saved on hazardous materials fees and improved sustainability.

Resumo e recomendações

Resumindo, slow thaw dry ice packs merge dry ice and gel technology to deliver longlasting, moisturefree cooling for cold chain shipments. By slowing sublimation and creating multiple temperature zones, these packs keep frozen and refrigerated products safe for up to 72 horas. Proper insulation, ventilation and accurate refrigerant calculations are essential to maximize performance. Always follow safety guidelines—use gloves, vent packages and label them correctly—to protect yourself and comply with regulations. By investing in reusable hybrid packs, you reduce hazardousmaterials fees, lower CO₂ usage and support sustainability goals.

Plano de ação

Avalie suas necessidades de remessa: Determine temperature requirements, transit duration and regulatory constraints. Use the refrigerant table above to estimate the number of hybrid pack sheets.

Choose the right pack: Select a slow thaw design that matches your product category (alimentos congelados, pharmaceuticals or mixed goods). Para remessas sob 24 horas, gel packs may suffice; for longer or ultracold shipments, hybrid packs or multizone systems are recommended.

Follow best practices: Prechill your containers, calculate dry ice and gel quantities accurately, provide ventilation and monitor temperatures during transit.

Engage with suppliers: Ask about pack reusability, CO₂ sourcing and compliance certifications. Look for ecofriendly materials and smart sensors to futureproof your cold chain.

Mantenha-se informado: Regulations and technology evolve quickly. Bookmark this guide and keep up with new innovations and regulatory updates.

Sobre Tempk

Nós somos Tempk, a pioneer in cold chain packaging solutions. Our team combines decades of industry experience with research and development to design advanced hybrid cooling systems. We offer medical cooler bags with phasechange materials, vacuuminsulated containers and slow thaw dry ice packs that meet GMP and GDP guidelines. Our products are reusable, environmentally friendly and provide consistent performance.

Ready to upgrade your cold chain? Contact us for personalized advice and choose the best slow thaw dry ice pack for your specific application.