How To Choose Between PET And PP For Disposable Drink Cups?

I. Background and Importance of drink cup Material Selection

Current Development Status and Packaging Needs of the Milk Tea Industry

As a core segment of China's fast-moving consumer goods market, the milk tea industry has experienced strong growth in recent years. Consumers' increasing demands for beverage quality have made packaging a key element in brand image building and consumer experience. Milk tea has a wide temperature range, from 0-5℃ iced drinks to 60-80℃ hot drinks, with some products even exceeding 90℃, placing stringent requirements on the durability of packaging materials. Simultaneously, the increasing proportion of takeout delivery further demands excellent sealing, impact resistance, and portability in packaging.

The Importance of PET and PP Materials in Drink Cup Applications

Currently, PET (polyethylene terephthalate) and PP (polypropylene) are the mainstream plastic materials in the disposable drink cup market. PET is known for its high transparency and gloss, making it suitable for high-end brand cold drink packaging; PP, with its excellent heat resistance and high cost-effectiveness, has become the preferred choice for hot drink packaging. Both PET and PP materials have their own characteristics in terms of cost, environmental friendliness, and functionality. Material selection directly affects product quality, cost control, and brand image.

 

II. Comparison of Basic Characteristics of PET and PP Materials

Comparison of Physical Properties

PET has excellent transparency, with a visible light transmittance exceeding 90%. Its texture is close to glass, and its appearance is exquisite. Its density is 1.35-1.40 g/cm³, placing it in the high-density category among plastics. It has good rigidity and stiffness, and extremely high tensile strength, comparable to aluminum foil, 3 times that of nylon, and 9 times that of PE film. PP has a density of 0.90-0.91 g/cm³, the lowest among all plastics, resulting in a lighter weight for the same volume. It is usually translucent or milky white and can be made into transparent products through special processes. It has good toughness and bending resistance, is not easily broken, and has higher reliability during transportation and use.

Comparison of Chemical Properties

PET has good chemical stability, is resistant to acids and alkalis, and is insoluble in common organic solvents such as hydrocarbons, alcohols, and esters, only soluble in tetrahydrofuran and methyl ethyl ketone. Its molecular structure is stable, and it does not release harmful substances at room temperature, meeting food contact safety standards. PP also possesses excellent chemical inertness, resisting acids, alkalis, salts, and most organic solvents. Its molecules contain methyl side chains, maintaining stability even at high temperatures. It is the only plastic that can be microwaved, and its chemical stability has been verified in practice.

Comparison of Food Contact Safety

III. Multi-dimensional Comparative Analysis

1. Cost Comparative Analysis

• Raw Material Price Differences

According to market data from 2025, the price of virgin PET was 7500-9500 yuan/ton, and recycled PET was 4500-7000 yuan/ton; virgin PP was 7800-9200 yuan/ton, and recycled PP was 4000-6000 yuan/ton. Superficially, PP is slightly cheaper, but its advantage is more significant when considering density differences: PP has a much lower density than PET, making it lighter for the same volume. PP is 10-30% cheaper per unit weight than PET, resulting in a 20-30% cost advantage per unit volume.

• Processing Costs and Production Efficiency

PET drink cups are mainly produced using injection molding, while PP disposable drink cups can be produced using both injection molding and thermoforming. Injection molding offers high production efficiency and product precision, but requires significant investment in equipment and molds; thermoforming has lower equipment and mold costs, but lower efficiency and precision. Industry data shows that the cost per drink cup produced by injection molding (1 million drink cups) is 0.1-0.2 yuan lower than that of blister packaging. Injection molding has a clear advantage for mass production, while blister packaging offers more flexibility for small-batch customization. Furthermore, PET processing requires higher temperatures and pressures, increasing processing costs by 15-20% compared to PP.

• Transportation and Inventory Costs

In terms of transportation, PP has a lower density, resulting in a total weight 30-40% lighter for the same number of drink cups compared to PET, directly reducing shipping costs. For example, a 500ml drink cup weighs approximately 6 grams with PP and approximately 9 grams with PET, a 50% weight difference. Regarding inventory, PET is more rigid and less prone to deformation, allowing for stacking heights exceeding 20 layers, resulting in higher space utilization. PP is softer, with stacking heights limited to 15 layers, making PET more advantageous when storage space is limited.

2. Environmental Comparison Analysis

• Recyclability and Recycling System

PET is one of the plastics with the highest recycling rate. Globally, PET bottle recycling rates are 50-60%, while China's "scavenger system" achieves over 90% recycling. China has a well-developed recycling system and mature technology; recycled PET can be used to make fibers and films. PP recycling is poor, with China's rate below 10% due to heavy mixed pollution and high sorting costs. Although theoretically it can be recycled four times, it faces practical, technical, and economic obstacles. The US PP recycling rate is 44.9%, demonstrating that the completeness of the recycling system is crucial to the recycling rate.

• Biodegradability and Environmental Impact

Traditional PET and PP are both non-biodegradable, petroleum-based plastics, requiring hundreds of years to degrade in the natural environment. In recent years, companies have developed biodegradable PP. With the addition of special additives, it can decompose under specific conditions. For example, PP with added oxidizing biodegradable agents degrades by over 60% within six months, more than four times that of traditional PP. However, the cost is 20-30% higher than traditional PP, limiting large-scale applications. In terms of carbon footprint, energy consumption in the production process is: PP≈PE-LD>PET>PLA; carbon emissions are: PET>PE-LD≈PLA>PP, with PP having a slight advantage in carbon emissions.

• Impact of Regional Environmental Regulations

China's plastic restriction policies have profoundly influenced the choice of materials for drink cups. The "Implementation Opinions of Guangdong Province on Further Strengthening the Governance of Plastic Pollution" requires that by the end of 2020, all restaurants in the province should ban non-degradable single-use plastic straws and should not proactively provide non-degradable single-use plastic tableware; by the end of 2022, restaurants in county-level built-up areas and scenic spots should ban non-degradable single-use plastic tableware; and by the end of 2025, the consumption intensity of non-degradable single-use plastic tableware in the urban catering and takeaway sector should be reduced by more than 30%. Huizhou City strictly implements the provincial policy, and by the end of 2025, all farmers' markets and postal express outlets in the city will ban non-degradable plastic bags and plastic packaging, making degradable or highly recyclable materials the preferred choice.

3. Comparative Analysis of Heat Resistance

• Temperature Range and Heat Deflection Characteristics

PET has poor heat resistance, with a glass transition temperature of approximately 75℃. Above 70℃, it transitions from a glassy state to a highly elastic state, causing the drink cup to shrink, soften, and deform. Although its melting point reaches 250℃, the glass transition temperature is the key factor for actual use. PP has excellent heat resistance, with a melting point of 165-170℃ and a heat deflection temperature of 100-135℃ (depending on type and additive formulation). Ordinary PP has a heat deflection temperature of 100℃, while specially treated high-temperature resistant PP reaches 135℃. Its glass transition temperature is below 0℃, and its crystalline region is stable at room temperature and hot water temperatures, while the amorphous region molecular chain segments are sufficiently rigid.

• Applicability in Different Temperature Scenarios

In cold beverage scenarios (0-5℃), both PET and PP are suitable, with no deformation or performance changes. Furthermore, PET's cold resistance (-40℃) is superior to PP's (0℃). Significant differences exist in hot beverage scenarios (60-80℃, some exceeding 90℃): PET drink cups are only suitable for beverages below 70℃, deforming above this temperature; PP drink cups can safely hold 100℃ boiling water and withstand 120℃ without deformation. Actual testing showed that a PP5 drink cup filled with 98℃ hot water did not deform, while ordinary PET drink cups began to soften at 75℃.

• High-Temperature Safety Assessment

PP exhibits outstanding high-temperature safety, releasing no harmful substances. This is the core reason for its use in microwave-safe tableware. Using temperatures below 100℃ fully complies with food safety standards, and there is no migration of harmful chemicals at 120℃. PET may release acetaldehyde and antimony (production catalyst) at high temperatures. Although the content meets standards, there is still a potential risk affecting taste and health.

IV. Comparative Analysis of Printing Effects

Surface Tension and Ink Adhesion

PET has a surface tension of 40-43 mN/m, while PP only has 34 mN/m. Plastic film printing requires a surface tension of at least 38 mN/m to ensure ink wetting. PP requires corona or flame treatment before printing. After corona treatment, the surface tension increases to 40-44 mN/m, and ink adhesion increases by 300%. PET, with sufficient surface tension, can theoretically be printed directly, but in actual production, corona treatment is also used to improve the effect.

Printing Process Adaptability

Both PET and PP are compatible with screen printing, offset printing, UV printing, and heat transfer printing. Screen printing is suitable for small-batch, multi-color printing, producing thick ink layers, vibrant colors, and can print on curved surfaces, but has low resolution. Offset printing has high resolution, is suitable for large-batch, intricate pattern printing, and strong color expression, but requires high adhesion to the plastic surface and necessitates surface treatment. UV printing uses ultraviolet light to instantly dry the ink, resulting in fast curing, vibrant colors, and scratch resistance; it is an advanced technology for plastic printing.

Special Processes and Appearance Effects

Both support special processes such as hot stamping, silver stamping, matte finish, and lamination. Hot stamping adds a metallic texture, matte finish creates a unique tactile feel, and lamination protects the pattern and improves scratch resistance. PET's high transparency and gloss give it a natural advantage in printing, better showcasing the colors and details of patterns. UV printing can achieve high color saturation and intricate patterns, suitable for gradients and complex designs. Although PP has lower transparency, it can also achieve good visual effects through special printing and surface treatment.

V. Comparison of Sealing Performance

drink cup Mouth Sealing Performance

PET has good rigidity and high drink cup mouth hardness, resulting in high precision fit with the drink cup lid and stable sealing. PP is softer and the drink cup mouth is prone to deformation, but good sealing can be achieved through optimized design and material modification. Industry testing standards require that a qualified drink cup remain leak-free under 50kPa pressure for 30 minutes, leak-free under 200kPa, and that the drink cup lid not detach or deform under 350kPa. Both PET and PP drink cups can meet these standards, but PP drink cups require more precise molds and stricter production control.

drink cup Lid Matching and Compatibility

PET drink cups commonly use snap-on lids, relying on physical fastening for sealing. PP drink cups can be snapped, screwed on, or heat-sealed; screw-on lids with sealing rings provide better sealing. Actual testing showed that PP caps with silicone rings exhibited a leakage rate of only 0.3% after 5 kilometers of transport by tricycle, compared to 7% leakage of commercially available snap-on PET caps under the same conditions. PP's sealing advantage is significant in specific scenarios.

Differences in Liquid Barrier Properties

PET offers excellent gas barrier properties, preventing oxygen and carbon dioxide penetration, making it suitable for carbonated beverage packaging. PP has good water vapor barrier properties, maintaining stable performance in humid environments, and exhibits extremely low water absorption (0.03-0.04%). Both are suitable for general milk tea storage; however, in special cases, the choice depends on the product characteristics: for example, milk tea containing tapioca pearls or coconut jelly that requires refrigeration, PP's moisture-proof advantage is more crucial.

IV. Application Scenarios Adaptability Analysis

1. Application Analysis in Cold Drink Scenarios

• Performance in the 0-5℃ Temperature Range

Both PET and PP are suitable for this temperature range. PET's high transparency perfectly showcases the color layers and ingredients of milk tea, enhancing visual appeal, especially suitable for fruit tea and layered beverages. While PP has slightly lower transparency, its special processing allows for the production of transparent drink cups, and its good toughness and impact resistance prevent it from becoming brittle or breaking easily at low temperatures, reducing breakage rates during delivery.

• Consumer Experience and Brand Image

Over 70% of consumers pay attention to the appearance and material of drink cups. PET drink cups, with their exquisite appearance, enhance the brand's premium feel, aligning with the quality pursuits of young consumers. In the social media era, they easily inspire photo sharing, aiding brand promotion. Some consumers believe that PP drink cups have a good feel and thick texture, making them "worth the price," suitable for brands emphasizing "health and nature"; furthermore, PP drink cups are easy to design with anti-slip features, improving the grip experience.

2. Hot Beverage Application Analysis

• Performance in the 60-80℃ Temperature Range

Hot beverage temperatures are typically 60-80℃, with some exceeding 90℃. PET drink cups deform and become unusable above 70℃; PP drink cups can safely hold 100℃ boiling water without deformation. Actual testing showed that a PP5 drink cup held 98℃ hot water without any issues, making it the preferred packaging for hot beverages, especially suitable for hot coffee and tea requiring insulation.

• Insulation Performance and Ease of Use

PET has a slightly higher thermal conductivity than PP, resulting in faster heat dissipation under the same conditions. However, actual insulation performance relies more on the drink cup structure (such as double-layer or vacuum insulation). PP drink cups offer significant advantages in use: they do not deform at high temperatures, consumers can hold and drink directly without a drink cup sleeve, reducing usage costs and complexity; and they can be directly microwaved, making them suitable for products requiring secondary heating.

3. Analysis of Delivery Scenarios

• Impact Resistance During Transportation

Drink cups delivered for takeout need to withstand vehicle bumps and collisions during loading and unloading. PET has high strength but poor toughness, making it easily broken by impact. Its brittleness increases at low temperatures, raising the risk of breakage. PP, on the other hand, has good toughness and elasticity, is resistant to deformation, and is less prone to breakage. Actual measurements show that PET drink cups have a 5-8% breakage rate during transportation, while PP drink cups only have a 1-2% breakage rate. The difference is even more pronounced over long distances or in poor road conditions.

• Leakage Prevention Requirements

Leakage is a major cause of customer complaints for milk tea takeout, accounting for 15-20%. PP material's flexibility is well-suited to the sealing design of drink cup lids, especially when paired with silicone sealing rings. Under various transportation conditions, the leakage rate is less than 0.5%, far exceeding the industry average, making its leak-proof performance more reliable.

4. Analysis of In-Store Drinking Scenarios

• Appearance and Brand Display

In-store consumers directly contact the drink cups. PET's high transparency and gloss give it a refined and high-end look, suitable for high-end brands. The transparent drink cup body can also showcase the production process, increasing consumer interest and trust. PP, with its frosted and pearlescent surface treatments, creates a unique texture, suitable for understated brands. Furthermore, PP's color stability ensures printed designs don't fade easily, maintaining a consistent brand image.

• Consumer Experience

PET drink cups' transparency allows consumers to clearly see the remaining beverage, avoiding awkward drinking situations. The elegant drink cup design enhances the drinking experience. PP drink cups have a warm surface texture, unlike the cold feel of PET, and are easy to texture with anti-slip patterns. Even with condensation on the drink cup walls during summer, they remain non-slip, improving user comfort.

V. Comprehensive Evaluation

PET and PP are evaluated from five dimensions (out of 100 points): cost, environmental friendliness, heat resistance, printing effect, and sealing performance.