A brief analysis of the error causes and solutions in the flame retardant effect test of linen fabrics
As a popular raw material for living room fabrics in developed countries, flax fiber is known for its excellent moisture absorption and dissipation, beautiful finish, strong tensile strength, acid and alkali resistance, corrosion resistance, good health care properties and unique Characteristics such as breathability, smoothness, roughness, boldness, natural texture, soft tones, and crispness are widely used. From the perspective of fire protection in the living room, fire-proof finishing of flax fibers used as tablecloths, sofa cloths, wall coverings, curtains and bedding is imperative.
At present, the more common fire protection effect measurement methods include: vertical burning method to measure the fabric’s ability to prevent afterburning, smoldering and char length; measuring the limiting oxygen index (LOI) or oxygen demand index (OI) to analyze its flammability properties; determine the durability of the fireproofing effect by measuring the number of washes; determine the fiber thermal decomposition temperature, decomposition process and decomposition products through thermal analysis and gas chromatography analysis. This article mainly analyzes the errors that are likely to occur when using the vertical combustion method and the durability effect method and discusses their solutions.
1 Method for measuring fire protection effect
The fire protection effect measurement methods adopted in this study are mainly the vertical combustion method and the durability effect method.
The vertical burning method is to cut the fabric sample after fireproofing into rectangular strips of specified size. After contacting one end of the strip with a flame of a specified height for a period of time, remove the flame and calculate the remaining burning time and smoldering of the cloth sample. (no open flame) time, and after it is completely extinguished, measure the length of the carbonized area (char length) of the cloth sample using the prescribed method to measure the effect of the fabric after fireproofing; the durability effect method is to clean the cloth sample after fireproofing according to the prescribed method. Then measure the various indicators of its fire protection effect, and measure the finishing effect of the fabric after smoldering by the number of washes.
2 Error causes and solutions
When measuring the fire protection effect of the vertical combustion method, the main technical indicators are: afterburning time, smoldering time and char length; the main technical indicator of the durable effect method is the number of washes. During many tests, I found that whether it is the measurement of afterburning time, smoldering time, char length or the number of washing resistance, it is easy to produce test errors, which will lead to errors in measuring the effect of fireproof finishing. The following is a detailed analysis of the causes of errors and their solutions.
2.1 Measuring afterburning time and smoldering time
When measuring the afterburning time and smoldering time with the LLY-07 vertical combustion tester, large errors often occur because the fabric burning condition is observed with the naked eye and the timer is manually controlled.
Taking Table 1 as an example, the afterburning time and smoldering time of linen fabrics after fireproofing are 1. 0s and 0.9s respectively. It is not easy to see accurately with the naked eye, not to mention the need to control the time by hand! Therefore, the error is often larger. The solution is to improve the instrument and use infrared rays to test the burning process of the fabric and automatically record the time.
2. 2 Measuring carbon length
The vertical burning method adopts a manual method to measure the char length, using the weight of a heavy hammer to naturally tear the fabric. Due to the different techniques of testers, it is easy to produce errors. The solution is to fix the testers and strictly follow the operating procedures.
2.3 Measuring the number of washable times
When measuring the washing resistance of linen fabrics after fire-proof finishing, it often needs to go through dozens of cleaning processes, and some performance tests must be carried out after each cleaning, so systematic errors are often caused, which requires testers to be careful and Operate accurately and minimize errors.
Others, because linen fabrics need to be cleaned many times during the post-fire finishing process, resulting in “flash” and changes in fabric size, which affects the measurement of technical indicators such as “carbon length”, thus causing errors, which requires Develop a more reasonable process to completely avoid the occurrence of the above situations.
3 Conclusion
Through research, it was discovered that there are many factors that cause errors in testing the fire-proof finishing effect of linen fabrics, but they mainly fall into two categories: caused by fire-proofing technology and artificially caused during testing. In this regard, we can make targeted improvements to improve the accuracy of the test results, so as to select the best fire-proof finishing process for linen fabrics and make the fire-proof finishing effect of linen products even better.
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