What Points Should Be Focused on in the Testing of Round Plastic Bowl Samples?
author: Iris
2025-12-26
I. Introduction
Round plastic bowls, as an important component of daily tableware, have a quality and safety directly related to consumer health and user experience. Household and commercial round plastic bowls differ significantly in their usage environment, frequency, and intensity. Household use primarily involves relatively mild conditions, such as daily serving of hot food, refrigeration, and microwave heating, while commercial use faces more rigorous challenges, such as high-frequency use, high-temperature sterilization, and mechanical cleaning. This differentiated usage demand necessitates the development of corresponding standards and methods for quality testing tailored to different scenarios.
II. Durability Testing (Differences between Household and Commercial Scenarios)
2.1 Durability Requirements in Household Scenarios
Household round plastic bowls are used in relatively mild conditions, mainly including daily serving of hot food, refrigeration, and microwave heating. Based on different usage frequencies and intensities, household scenarios can be subdivided into the following situations:
- Daily meals: Regular use for meals 3-4 times a day, with temperatures generally between 60-80℃.
- Microwave heating: Occasionally used for microwave heating, with temperatures usually not exceeding 120℃, and heating time generally within 2-3 minutes.
- Refrigerated storage: Used for food refrigeration, with temperatures between 0-10℃.
- Room temperature storage: Used for storing dry food, snacks, and other room-temperature foods.
Based on the above usage scenarios, the durability requirements for household plastic salad bowls are relatively low, but they still need to meet the following basic requirements:
- Heat resistance: PP material should withstand a temperature of 120℃, PE material should withstand a temperature of 100℃, and PS material should withstand a temperature of 70℃.
- Impact resistance: No cracking or functional damage should occur after a free fall from a height of 1 meter onto a hard surface.
- Dimensional stability: Within the normal operating temperature range, dimensional changes should not affect the functionality.
- Chemical resistance: Should have a certain resistance to acids, alkalis, and oils in everyday food.
2.2 Durability Requirements in Commercial Scenarios
Commercial round plastic bowls face a more rigorous usage environment, mainly reflected in the following aspects:
- High-frequency use: Restaurants, canteens, and other places may use them dozens or even hundreds of times a day.
- High-temperature sterilization: Must withstand high-temperature sterilization in a dishwasher, with water temperatures typically between 85-95℃ and sterilization time ≥90 seconds.
- Mechanical cleaning: Cleaned using equipment such as dishwashers, withstanding high-pressure water jet impact.
- Stackable storage: Requires good stacking performance for easy storage and transportation.
- High-intensity use: May be used to hold high-temperature food, withstand significant pressure, etc.
Therefore, commercial round plastic bowls have more stringent durability requirements:
- Heat resistance: Should withstand temperatures above 120℃, and in some scenarios, temperatures of 130℃.
- Impact resistance: No breakage after dropping from a height of 1.2 meters for ≥100 times, with impact energy of 5J.
- Abrasion resistance: Abrasion cycles ≥5000 times, mass loss ≤0.1g.
- Chemical resistance: Good resistance to strong acids, strong bases, and organic solvents.
- Fatigue resistance: Able to withstand repeated hot and cold cycles and mechanical stress.
2.3 Impact Performance Test
Impact performance is an important indicator for evaluating the durability of round plastic bowls, directly related to whether the product is prone to breakage during use. The main test methods include the following:
- Free fall test: The sample is freely dropped from a specified height onto a hard, smooth horizontal surface and observed for breakage or functional damage. Household products are generally dropped from a height of 1 meter, while commercial products are dropped from a height of 1.2 meters. The test needs to simulate different drop angles, including bottom landing, edge landing, and side landing.
- Pendulum impact test: Using a pendulum impact testing machine, a pendulum of a specified weight is lifted to a certain height and then released to impact the sample, recording the energy at the time of failure. The test standard refers to ISO 179-1:2020 Plastics — Pendulum impact test method.
- Falling ball impact test: A steel ball of a specified weight is dropped from a certain height to impact the sample, and the sample is observed for breakage. Common test conditions include: a 500g steel ball dropped from a height of 1m, or a 50g steel ball dropped from a height of 500mm. Dynamic Impact Testing: Simulates the impacts that a product may experience during actual use, such as collisions and crushing.
The criteria for determining test results include:
- Fracture determination: If the sample shows penetrating cracks or fragments detach, it is considered fractured.
- Functional damage: Even without a fracture, if deformation, cracking, or other conditions that affect normal use occur, it is considered a failure.
- Impact energy: The minimum impact energy required to damage the sample is recorded as a quantitative indicator of the product's impact resistance.
2.4 High-Temperature Deformation Testing
High-temperature deformation testing is an important method for evaluating the ability of plastic salad bowls to maintain their shape and function under high-temperature conditions. The test methods include the following:
- Constant Temperature Heating Test: The sample is placed in a constant temperature chamber and maintained at a specified temperature for a certain period of time, observing the deformation of the sample. Common test conditions include: 100°C for 4 hours, with deformation ≤3%; or 120°C for 30 minutes, observing for significant deformation.
- Heat Distortion Temperature Test: Using a heat distortion temperature tester, the temperature at which the sample undergoes a specified amount of deformation is measured under specified load and heating rate. The test standard refers to ASTM D648.
- Thermal Cycling Test: The sample is repeatedly cycled between high and low temperatures, observing changes in the sample's performance. Common test conditions are: -20°C to 100°C, 50 thermal cycles, observing for deformation or cracks.
- Microwave Heating Test: The sample is placed in a microwave oven and heated at a specified power and time, observing the deformation of the sample and whether harmful substances are released.
The criteria for determining test results include:
- Deformation amount: Measure the dimensional changes of the sample at high temperatures and calculate the deformation rate. Generally, the deformation rate should be ≤3%.
- Appearance changes: Observe whether the sample surface shows bubbles, discoloration, cracking, etc.
- Functional impact: Check whether the deformation affects the normal use of the product, such as the lid not sealing properly or the product not being able to sit stably.
2.5 Aging Resistance and Cyclic Use Testing
Aging resistance is an important indicator for evaluating the long-term performance of round plastic bowls, including natural aging and artificial accelerated aging.
Natural Aging Test: The sample is exposed to the natural environment, and its performance changes are regularly checked, including appearance, mechanical properties, and chemical properties. This method has a long cycle, generally requiring several years.
Accelerated Artificial Aging Tests: Using aging test chambers, the aging process of samples is accelerated by simulating factors such as light, heat, oxygen, and humidity in the natural environment. Common test methods include:
Natural Aging Test: The sample is exposed to the natural environment, and its performance changes are regularly checked, including appearance, mechanical properties, and chemical properties. This method has a long cycle, generally requiring several years.
Accelerated Artificial Aging Tests: Using aging test chambers, the aging process of samples is accelerated by simulating factors such as light, heat, oxygen, and humidity in the natural environment. Common test methods include:
- UV aging: The sample is irradiated with a UV lamp. The test standard refers to ASTM D4329-2013, and performance changes are generally evaluated after 168 hours of irradiation.
- Hot air aging: The sample is aged in high-temperature air. The test standard refers to GB/T 3512-2014, and aging is generally performed at 70°C for 7 or 14 days.
- Humid heat aging: The sample is aged in a high-temperature and high-humidity environment, simulating the usage environment in tropical regions.
- Cyclic Use Tests: Simulating the repeated use process of the product in actual use, the test items include:
- Dishwasher cycle test: The sample is placed in a dishwasher and cleaned for 50 or more cycles according to standard procedures, checking for appearance, dimensional stability, and surface wear.
- Thermal cycling test: The sample is repeatedly cycled between high and low temperatures, such as soaking in 100°C hot water for 30 minutes, then freezing at -20°C for 24 hours, and repeating this process multiple times.
- Mechanical fatigue test: Repeated mechanical stress, such as bending and stretching, is applied to the sample to test its fatigue life.
Evaluation indicators for test results include:
- Appearance changes: Color change, gloss change, surface wear, etc.
- Changes in mechanical properties: Retention rate of tensile strength, bending strength, impact strength, etc., generally requiring a retention rate of ≥80%.
- Changes in chemical properties: Changes in migration amount, production of harmful substances, etc.
- Functional performance: Whether sealing performance, stability, and ease of use remain good.
III. Stability Testing
3.1 Static Stability Test
Static stability refers to the ability of a round plastic bowl to resist tipping when placed statically, which is a basic requirement to ensure safe use. The main test methods include the following:
Tilt angle test: The sample is placed on a platform with an adjustable tilt angle, and the tilt angle is gradually increased. The critical angle at which the sample tips over is recorded. Generally, the critical angle should be ≥15°, and a higher requirement is needed for products containing liquids.
Center of gravity height determination: The stability is evaluated by measuring the center of gravity of the sample. The lower the center of gravity, the better the stability. The center of gravity can be determined during testing using a center of gravity measuring instrument or through geometric calculations.
Bottom anti-slip test: Evaluates the impact of the plastic salad bowl bottom design and material on anti-slip performance.
Center of gravity height determination: The stability is evaluated by measuring the center of gravity of the sample. The lower the center of gravity, the better the stability. The center of gravity can be determined during testing using a center of gravity measuring instrument or through geometric calculations.
Bottom anti-slip test: Evaluates the impact of the plastic salad bowl bottom design and material on anti-slip performance.
Test methods include:
Friction coefficient test: Using a friction coefficient tester, measure the friction coefficient between the round plastic bowl bottom and different surfaces (such as glass, ceramic, stainless steel, etc.). Generally, a friction coefficient of ≥0.5 is required.
Anti-slip pad effect test: For products with anti-slip pads, test the anti-slip effect of the pads under different conditions (dry, wet, oily, etc.).
Anti-slip pad effect test: For products with anti-slip pads, test the anti-slip effect of the pads under different conditions (dry, wet, oily, etc.).
- Full-load stability test: Fill the sample with a specified weight of water or other medium and test its stability under full load. Tests include:
- Full-load tilt test: After filling with water, perform a tilt angle test to observe whether it is easily tipped over.
- Full-load movement test: Simulate the stability during carrying, testing whether spillage occurs easily.
- Stacking stability test: For products that need to be stacked for storage, test their stability when stacked:
- Stacking height test: Test the maximum safe stacking height, generally requiring at least 10 stable stacks.
- Stacking pressure test: Apply a certain pressure in the stacked state and observe whether collapse or deformation occurs.
- Vibration test: Simulate vibrations during transportation and test the stability of the stack.
3.2 Dynamic Stability Test
Dynamic stability refers to the ability of the round plastic bowl to maintain balance when subjected to external forces, reflecting the safety of the product during actual use.
Test methods include:
- Thrust test: Use a thrust testing machine or manually apply horizontal thrust to test the stability of the sample when subjected to lateral force. Record the minimum thrust required to tip the sample over.
- Impact test: Simulate possible impacts during use, such as elbow collisions, object drops, etc. During the test, an object of a specified weight is used to impact the sample from a certain angle and speed, and whether it tips over is observed.
- Vibration test: Place the sample on a vibration table and apply vibrations of different frequencies and amplitudes to observe the stability of the sample.
- Movement stability test: Simulate the stability during carrying and walking. Test items include:
- Walking test: The tester carries the sample filled with water for a certain distance and observes whether there is spillage.
- Turning test: Simulate the centrifugal force during turning and test the stability of the sample.
- Stair climbing test: Simulates the jolting motion of going up and down stairs to test the stability of the sample.
- Liquid spill test: Evaluates the product's ability to prevent liquid spills when tilted or subjected to impact:
- Tilt spill test: The sample filled with water is tilted at a certain angle, and the amount of spilled water is measured.
- Impact spill test: A certain impact force is applied to the sample filled with water, and the amount of spilled water is measured.
3.3 Stability Assessment under Full Load Conditions
Stability under full load conditions is the most critical safety indicator in practical use, especially when the black plastic bowls contain high-temperature liquids such as hot soup or oil, as spills can cause serious burns. Assessment methods include:
- Center of Gravity Offset Test: Measure the center of gravity position under full load conditions and calculate the center of gravity offset. A larger offset indicates poorer stability.
- Moment of Inertia Test: Assess the product's resistance to tipping by measuring the moment of inertia under full load. A larger moment of inertia indicates better stability.
- Dynamic Response Test: Simulate various actions during use, such as sudden stops, turns, and bumps, to test the dynamic response of the product under full load.
Extreme Condition Testing: Test stability under extreme conditions, such as:
- Edge Placement Test: Place a portion of the round plastic bowl suspended over the edge of a table to test the maximum overhang distance.
- Single-Foot Support Test: Simulate localized force on the bottom of the round plastic bowl to test stability.
Safety Assessment: A safety rating is assigned based on the following factors:
- Tipping Risk Level: Based on the test results, the product is classified into high, medium, and low risk levels.
- Usage Restrictions: Appropriate usage restrictions and warning labels are developed based on the stability test results.
- Improvement Suggestions: Design improvement suggestions are provided to address any stability issues.
3.4 Bottom Design and Anti-Slip Measures Assessment
The bottom design is a key factor affecting the stability of round plastic bowls. A reasonable bottom design not only improves stability but also protects the tabletop from damage. Assessment points include:
Bottom Shape Design:
- Flat Bottom Design: The stability of flat-bottomed round plastic bowls mainly depends on the size of the bottom area. Generally, the ratio of the bottom area to the top opening area should be ≥0.6 to ensure good stability.
- Concave Bottom Design: Some products use a concave bottom design, which increases the contact area with the tabletop and improves stability.
- Convex Bottom Design: Some products use a convex bottom design, combined with anti-slip pads, to adapt to different tabletop shapes.
Bottom Material Selection:
- Soft Materials: Such as silicone and rubber, which have good anti-slip properties and shock absorption.
- Hard Materials: Such as PP and PE, whose anti-slip performance is improved through surface treatment (e.g., matte finish, stripes).
- Composite Design: The bottom uses a combination of different materials, such as a hard main body with a soft anti-slip pad. Evaluation of Anti-Slip Measures:
- Anti-slip mat performance testing: Testing the anti-slip effect of the anti-slip mat on different surfaces (glass, ceramic, wood, marble, etc.).
- Anti-slip texture design: Evaluating the impact of the depth, density, and shape of the anti-slip texture on the anti-slip effect.
- Anti-slip material durability: Testing the performance retention of the anti-slip material after repeated use.
Bottom Height and Slope Design:
- Round plastic bowl bottom height: An appropriate round plastic bowl bottom height can increase stability; generally, the round plastic bowl bottom height should be ≥10mm.
- Round plastic bowl bottom slope: The round plastic bowl bottom can be designed with a certain slope to direct liquids towards the center and prevent accumulation at the edges.
Adaptability to Special Scenarios:
- Outdoor use: Evaluating the product's stability on uneven surfaces (such as grass, sand, etc.).
- In-vehicle use: Evaluating the product's stability during vehicle movement.
- High-temperature environment: Evaluating the performance changes of the anti-slip material at high temperatures.
IV. Conclusions and Recommendations
4.1 Summary of Key Testing Points
Through a comprehensive analysis of the key quality testing points for black plastic bowls, we can draw the following key conclusions:
- Safety testing is paramount: Quality testing of round plastic bowls must prioritize safety, focusing on the control of harmful substances such as heavy metal migration, plasticizer residue, and formaldehyde release. In particular, the GB 4806.7-2023 standard, implemented on September 6, 2024, added requirements for the total migration of aromatic primary amines, indicating stricter regulation of food safety in my country.
- Scenario differences determine testing priorities: The usage environments of household and commercial round plastic bowls differ significantly, and testing requirements should also differ. Household products should focus on the safety and convenience of daily use, while commercial products require stricter durability and hygiene performance requirements.
- Performance testing is crucial: In addition to safety indicators, the physical performance of the product is equally important. High-temperature deformation resistance, impact resistance, and stability directly affect the safety and lifespan of the product. The stability when filled with liquid is particularly important for user safety.
- Cleaning performance affects user experience: Good cleaning performance not only reduces usage costs but also improves user satisfaction. Surface smoothness, material hydrophilicity, and stain resistance are all important factors affecting cleaning convenience.
- Full life cycle management: Quality control should cover the entire process from raw material procurement, production and processing, finished product inspection, to use and maintenance. Establish a comprehensive quality traceability system to ensure the traceability of product quality.
4.2 Quality Control System Recommendations
Based on the above analysis, the following quality control system is recommended:
Raw Material Control:
- Strictly implement the incoming inspection system; each batch of raw materials must be accompanied by a certificate of conformity.
- Establish a raw material database to record information such as the source, batch number, and test results of each batch of materials.
- Conduct regular audits of raw material suppliers to ensure the stability of supply quality.
Production Process Control:
- Develop detailed production process specifications, clearly defining key control points.
- Establish a process inspection system to monitor key processes in real time.
- Strengthen equipment maintenance to ensure the normal operation of production equipment.
- Establish an employee training system to improve operational skills and quality awareness.
Finished Product Inspection Control:
- Establish a graded inspection system, determining inspection items and frequency based on product use.
- Equipped with advanced testing equipment to ensure the accuracy of test results.
- Establish a sample retention system to preserve a certain number of samples for re-examination.
- Conduct regular type testing to verify the stability of product quality.
Quality Traceability System:
- Establish a product identification and traceability system to ensure that each product has a unique identifier.
- Record key information in the production process, including raw material batch numbers, production time, and operators.
- Establish a customer feedback mechanism to promptly address quality issues.
- Conduct regular quality analysis to continuously improve product quality.
4.3 Future Development Trends
With consumers' increasing awareness of food safety and environmental protection, the quality requirements for round plastic bowls will become increasingly stringent. Future development trends include:
- Continuous improvement of standard systems: It is expected that more harmful substances will be included in the control scope in the future, and testing standards will become more stringent. In particular, the control of endocrine-disrupting substances will become a key focus.
- Application of new materials and technologies: The application of new materials such as biodegradable plastics and bio-based plastics will become more widespread, requiring the establishment of corresponding testing standards and methods.
- Intelligent testing technology: Artificial intelligence, big data, and other technologies will play a greater role in quality testing, achieving automation and intelligence in testing.
- Life cycle assessment: Life cycle environmental impact assessment from product design to waste disposal will become an important consideration.
- International standard harmonization: With the development of international trade, the harmonization of standards among countries will become a trend, and companies need to pay attention to the latest developments in international standards.
In short, quality testing of black plastic bowls is a crucial link in ensuring food safety and consumer health. Companies should establish a comprehensive quality control system, strictly adhere to relevant standards and requirements, and continuously improve product quality. At the same time, regulatory authorities should strengthen market supervision to ensure that consumers have access to safe and high-quality products. Only through the joint efforts of businesses, regulatory authorities, and consumers can a safe, healthy, and sustainable market environment be established.
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