Several customers ask me if polyester can be breathable. The answer is yes, but to arrive at this answer, it is recommended to ask the following questions:
How is the comfort of a garment measured? The comfort of a garment can be evaluated through various subjective and objective factors. Here are some common measures used to assess the comfort of a garment:
Breathability: The ability of a garment to allow air circulation and sweat evaporation is a key factor in comfort. Laboratory tests can be conducted to measure the air permeability and the moisture absorption and release capacity of the fabric.
Flexibility and elasticity: A garment that allows free and comfortable movement of the body is considered more comfortable. The flexibility and elasticity of the fabric can be evaluated through stretching and recovery tests, which measure its ability to adapt to the user's movements.
Tactile sensation: The softness, smoothness, and texture of the fabric also influence comfort. Subjective tests can be conducted with panels of evaluators who rate the softness and tactile sensation of the garment.
Fit and ergonomic design: Proper fit and ergonomic design contribute to the comfort of a garment. The design of patterns, seams, and specific features to fit the shape and movements of the human body can be evaluated by design and ergonomics experts.
Thermal sensation: The ability of a garment to regulate body temperature is important for comfort. Thermal insulation and heat transmission tests can be conducted to evaluate how the garment manages temperature in different conditions.
It is important to note that comfort is subjective and can vary according to individual preferences. Therefore, objective tests can provide a general assessment, but user feedback and personal experiences are also valuable for evaluating the comfort of a garment.
That being said, the two values that have been analyzed in the laboratory in order to provide a comfort guide and compare fabrics are Thermal Sensation and Breathability.
1- Thermal Sensation: The thermal sensation of a garment can be evaluated through objective tests and measurements. Here are some common methodologies used to test and assess thermal sensation:
Thermal insulation test: This test measures a garment's ability to retain body heat and provide insulation against cold. A thermal mannequin equipped with sensors that simulate heat production and heat loss from the human body is used. The garment is placed on the mannequin, and heat transfer through the garment is measured under different controlled temperature and humidity conditions.
Heat transmission test: This test measures a garment's ability to allow heat transfer from the body to the environment, which is essential for comfort in warm climates. Similar to the thermal insulation test, a thermal mannequin is used, but in this case, the garment's ability to dissipate body heat and maintain a comfortable body temperature is measured.
Subjective evaluation: In addition to objective tests, subjective evaluation is essential to measure thermal sensation. User opinions can be collected through questionnaires, interviews, or real-time evaluations of their level of thermal comfort when wearing the garment in different environmental conditions. These subjective opinions can provide valuable information about the personal perception of thermal sensation.
It is important to conduct tests under controlled and repeatable conditions to obtain reliable and comparable results. Additionally, specific textile industry standards and norms can provide more detailed guidelines and methodologies for evaluating the thermal sensation of a garment. For example, it is important to consider whether a garment is being tested in summer or winter, as the perception of comfort can vary considerably. Consulting experts in fabric testing and specialized laboratories is recommended to obtain technical advice and ensure an accurate evaluation of the thermal sensation of a garment.
2- Breathability: The breathability of a garment is evaluated through specific tests that measure the fabric's ability to allow air passage and sweat evaporation. Here are some common methodologies used to evaluate the breathability of a garment:
Air permeability test: This test measures the amount of air that can pass through a specific area of fabric in a given time. An instrument called an air permeometer is used, which applies a controlled pressure difference on both sides of the fabric and measures the airflow through it. The higher the airflow, the greater the breathability of the fabric.
Water vapor resistance test: This test measures the fabric's ability to allow sweat to evaporate. A fabric sample is placed in a tightly sealed test cell, and the rate of water evaporation through the fabric is measured. A higher evaporation rate indicates greater breathability.
Moisture absorption and release test: This test evaluates the fabric's ability to absorb moisture (e.g., sweat) and release it into the environment. The amount of moisture the fabric can retain and the speed at which it releases moisture can be measured. A fabric that efficiently absorbs and releases moisture is considered more breathable.
Subjective evaluation: Similar to thermal sensation, subjective evaluation is also important in assessing the breathability of a garment. Users can provide feedback on comfort and dryness while wearing the garment in different physical activity and temperature conditions.
While all three tests mentioned above are relevant for evaluating fabric breathability, their importance may depend on the specific context and requirements of the final product. There is no single definitive test that determines fabric breathability, as it is a complex attribute involving multiple factors.
However, generally, the air permeability test and water vapor resistance test are two widely used and considered important for evaluating fabric breathability. These tests directly measure the fabric's ability to allow airflow and sweat evaporation, which are key aspects of breathability.
The air permeability test evaluates the fabric's ability to allow airflow through it, which is important for good ventilation and air circulation. On the other hand, the water vapor resistance test measures the fabric's ability to allow sweat evaporation, which is crucial for maintaining a sensation of dryness and comfort.
The moisture absorption and release test is also relevant as it assesses how the fabric can absorb moisture and release it into the environment. Good moisture absorption and release capacity contribute to breathability by helping to keep the skin dry.
Ultimately, the choice of which test or combination of tests to use to verify fabric breathability will depend on the specific needs and standards of the industry in which the garment is used, as well as the manufacturer's preferences and product requirements.
What are the values to measure these tests, and what would be considered optimal results?
The values for measuring breathability tests can vary depending on specific industry standards, test protocols, and equipment used. Below are some common values used in breathability tests:
Air permeability test:
- Airflow: measured in liters per minute (L/min) or in cubic meters per square meter per second (m³/m²/s). Higher values indicate higher air permeability and, therefore, greater breathability.
Water vapor resistance test:
- Thermal resistance index (RET, Resistance-Evaporative-Transmissivity): measured in m²·Pa/W (or m²·K/W). Lower values indicate lower water vapor resistance and, therefore, greater breathability. For example, an RET of 0.5 would be considered highly breathable, while an RET of 6 would be considered less breathable.
Moisture absorption and release test:
- Moisture absorption capacity: measured in grams of water per square meter (g/m²). Higher values indicate greater moisture absorption capacity and, therefore, greater breathability.
- Evaporation rate: measured in grams per square meter per hour (g/m²/h). Higher values indicate a higher evaporation rate and, therefore, greater breathability.
It is important to consider that optimal results can vary depending on the intended use of the garment and specific user requirements. In general, for a garment to be considered breathable, higher values would be sought in air permeability tests, greater moisture absorption capacity, and higher rates of evaporation. On the other hand, lower values in the water vapor resistance (RET) test would indicate higher breathability.
It is advisable to consult specific industry standards and norms such as ASTM, ISO, or others, as they provide more detailed guidelines and specifications regarding optimal values and breathability ratings for different types of garments and specific applications.
As for current ISO standards, here are some examples, although please note that standards and norms can be updated over time:
ISO 9237: Determination of the permeability of textiles to air. This standard establishes a method for measuring the air permeability of fabrics and garments.
ISO 11092 (EN 31092): Determination of thermal resistance and water vapor resistance of textiles. This standard describes methods for measuring the thermal resistance and water vapor resistance of fabrics under sweating conditions.
ISO 15496: Determination of water vapor resistance of textiles - Sweat-plate method. This standard specifies a method for measuring the water vapor resistance of textiles using a sweat-plate.
ISO 2060: Determination of water absorption of cotton yarns and fabrics. This standard provides methods for determining the water absorption capacity of cotton yarns and fabrics.
ISO 105-E04: Determination of the resistance to washing of colored textiles. This standard describes methods for evaluating the colorfastness to washing of colored textiles.
It is important to consult the latest versions and updates of relevant ISO standards, as new editions or additional standards may have been published. I would recommend checking the official website of the International Organization for Standardization (ISO) for the most up-to-date information on specific standards related to textiles and garments.
What level of breathability RET could be considered low?
Regarding a low breathability RET value, an RET (Water Vapor Resistance) below 2 would indicate that the garment has moderately low resistance to the passage of water vapor. The RET value is used to measure a fabric's ability to allow water vapor (i.e., sweat) to pass through it.
In general, an RET value below 2 would be considered relatively low and suggests that the garment has good breathability. The lower the RET value, the better the garment's ability to allow sweat to evaporate and maintain comfort during physical activity or in hot conditions.
However, it is important to note that classification standards can vary depending on the industry and specific requirements. In some contexts, an RET of 2 may be considered very breathable, while in others, it may be considered moderately breathable. Therefore, it is advisable to consult specific industry or manufacturer standards or specifications for a more accurate assessment of breathability in relation to an RET value of 2.
Furthermore, it is important to emphasize that this would only be one value among the parameters that contribute to comfort. Other factors should also be considered to draw more precise conclusions. Additionally, it is important to remember that comparisons are more relevant when comparing similar materials, while comparing different materials can make it challenging to evaluate the results.
Can a polyester fabric offer good breathability?
The polyester is a synthetic material that can vary in terms of breathability depending on how it is manufactured and whether special treatments have been applied to the fabric. Generally, polyester is not as breathable as some natural fibers, such as cotton or linen, as it has a lower capacity to absorb and release moisture.
However, in the textile industry, technologies and special finishes have been developed to enhance the breathability of polyester. These treatments can include polyester fabrics with specific structures, micro-perforations, mesh or strategically placed ventilation panels, or water-repellent coatings that allow the transfer of water vapor while preventing the entry of external liquids.
Additionally, polyester is often used in combination with other fibers, such as elastane or nylon, to improve the elasticity and strength of garments. These blends can enhance the breathability and overall comfort of the garment.
Therefore, a polyester fabric can nowadays offer superior breathability and comfort compared to natural fibers like cotton. It is crucial to know the type of polyester fabric being used, as not all offer the same results.
In summary, although polyester is not inherently as breathable as some natural fibers, advancements in textile technology have allowed for improvements in its breathability. When choosing a polyester garment, it is advisable to look for fabrics with special treatments or features designed to enhance breathability and consider other factors such as fabric structure, ventilation, and overall garment design.
For example, with tetralobal filaments?
Tetralobal filaments are a specific form of fiber structure used in the manufacturing of polyester fabrics. These filaments have a four-lobed cross-sectional shape, which creates additional channels for air circulation and facilitates the evaporation of sweat.
The use of tetralobal filaments in the production of polyester fabrics can contribute to improved breathability compared to other types of conventional polyester fibers. The filament shape allows for increased airflow and better circulation, facilitating sweat evaporation and helping maintain a dry and comfortable feel during physical activity or in hot conditions.
However, it is important to note that the breathability of a fabric depends not only on the structure of the fiber used but also on other factors such as fabric construction, additional treatments, and garment design. Therefore, while tetralobal filaments can be a positive feature for enhancing polyester breathability, it is necessary to consider other aspects to obtain a comprehensive evaluation of the breathability of a particular fabric.
Who uses these high-performance technical fabrics?
Elite athletes, for example, often prefer materials that offer a combination of specific features to enhance their performance and comfort during sports activities. Although preferences may vary depending on the sport and individual preferences, polyester is widely used in sportswear due to its durability, resistance to wear, moisture absorption capacity, and comfort. Polyester fabrics can be treated with special technologies to improve breathability and moisture management, helping to keep the body dry and comfortable during physical activity. In other cases, fabrics with elastane (spandex) are also used, known for their high elasticity and stretchability, for swimwear, or nylon for its robustness, for outdoor jackets and pants.
In addition to the materials mentioned above, there are technical fabrics developed specifically for high-performance sports. These fabrics may include features such as water resistance, temperature management, and protection against UV rays.
As you can see after reading these lines, it is important to consider that preferences may vary among different uses, and one should always seek materials and garments specifically designed to meet each customer's demands in order to enhance users' performance, always taking into account factors such as the type of activity, environmental conditions, and individual needs.
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