Test report of textile fiber products made from soybean protein

Soybean protein fiber

Test Report of Comprehensive Properties of

 Soybean Protein Fibers

Department of Knitting Engineering, College of Textiles, Dong Hua University 

1.Wet Permeability and Moisture Vapor Transmission Characteristics

  In order to test and compare these two properties of Soybean fibers, 6 jersey fabric samples were knitted with 6 kinds of different yarns, as illustrated in Table 1.

Table.1 the Type of Yarn Material

                       Table.2 Parameters of Samples

  The wicking rates of first 10 min and the wetting areas of 1 min of all samples were tested, and the synthesized values of wet permeability were calculated, as illustrated in Table. 3.

Table.3 the Synthesized Values of Wet Permeability (Z)

  Table 3 shows that the synthesized values of wet permeability of PP and PE samples are highest in all the samples. And the synthesized value of wet permeability of Soybean sample is lower than that of PP and PE, but higher than other samples. The sequence of wet permeability of these samples is listed as follows:

D₃>D₂>D₁>D₅>D₆>D₄

  The water cup method was used to measure the quantities of permeated moisture vapor through the samples. In the experiment, the environment dry bulb temperature is 35℃, the wet bulb temperature 25℃, relative humidity is 35%, the test time is 2 hours, and the sample area is 32.75 cm². The tested quantities of permeated moisture vapor through the samples are listed in Table. 4.       

Table.4 the quantities of permeated moisture vapor through the samples   (g) 

  It is obvious that, from the data of Table.4, the moisture vapor transmission property of soybean sample is the best in all the samples. The sequence of the moisture vapor transmission property of these samples is listed as follows: 

 D₁>D₆> D ₅> D ₃> D ₄> D ₂

  The wet permeability of Soybean is lower than that of PP and PE but higher than PAN, PA and silk; while the moisture vapor transmission property of soybean sample is better than silk, PP, PE, PA, PAN. Therefore, soybean fiber is a kind of comfortable fiber with relatively good wet permeability, excellent moisture vapor transmission property and dry touch. 

2. Warmth retention property

   In order to test and compare the warmth retention property of Soybean fiber, 4 jersey fabric samples were knitted with soybean yarn, PAN yarn, cotton yarn and wool yarn, respectively. The parameters of samples are listed in Table. 5.

Table.5 Parameters of Samples

  The synthesized values of three heat parameters (warmth retaining rate, thermal resistance and thermal transmissivity) of all samples were tested and calculated, as illustrated in Table.6.

Table.6 synthesized values of heat parameters

  Table 6 shows that, the warmth retention property of soybean-fiber sample is similar with that of cotton sample, which is better than PAN sample but worse than wool sample.

3. Frictional, flexural and draping properties

  In order to test these three properties of soybean fibers, 14 fabric samples were prepared with different yarn materials and different textile structures. The parameters of these samples are listed in Table.7.       

                          Table.7 parameters of fabric samples

3.1 Frictional property

  The tested data of friction force and frictional coefficient of all samples are listed in Table.8.

Table.8 Friction force (F) and frictional coefficient ( )

  The sequence of the frictional property of the above mentioned yarn materials is: 

Silk> Soybean fiber/spandex >cotton>soybean> Chrysalis fiber

  The fictional coefficient of soybean fiber is just lower than that of Chrysalis fiber, which has the smoothest feeling.    

3.2 Flexural property

  The tested slide length (l) and calculated bending length (C), flexural rigidity (B), and bending modulus (g) of all fabric samples are listed in Table.9.

  Table.9 Slide length (l), bending length (C), flexural rigidity (B) and bending modulus (g)

  The sequence of the soft handle property of the above mentioned yarn materials is: 

Chrysalis fiber > Soybean fiber> Silk > cotton

3.3 Draping property

  The tested drape coefficient, wrinkle number and the subjective assessment of aesthetic feeling of all fabric samples are listed in Table.10.   

Table.10 The drape coefficient, wrinkle number and grade of aesthetic feeling

        Grade standard of aesthetic feeling

                  A with more wrinkles, and the wrinkles are smooth and well-distributed;

                  B the level between grade A and grade C; 

                  S with little wrinkle, and the wrinkles are irregular.

  The sequence of the draping property of the above mentioned yarn materials is: 

Chrysalis fiber > Soybean fiber> Silk

  According to the aesthetic principles (the shape of draped fabric with more wrinkles, and the wrinkles are smooth and beautiful), all the 14 fabric samples were assessed subjectively. The results of assessment indicate that the soybean fiber samples (No.7-9) and the Chrysalis fiber sample (No.10) have good aesthetic feeling and drape property.

4. Pilling property

  The pilling property of 3 knitted fabric samples, which are made from 32^s soybean yarns, 32^s cotton yarns and 32^s PAN yarns respectively, were tested with nylon brush for 50 revolutions and with fabric for 50 revolutions. The test results indicate that the pilling degree of soybean sample is similar with that of cotton sample and better than that of PAN sample; while the fuzzing fibers of soybean sample are much longer than that of cotton and PAN samples.

In a word, due to the low frictional coefficient, low crimp number and low crimp stability of soybean fiber, the soybean fabric sample is easy to fuzzing but not easy to pilling. According to GB4801.1—84, the pilling property of soybean sample is grade 2, while that of cotton sample is grade 1.5 and PAN sample is grade 1.

5. Antistatic property

  The tested electricity parameters of soybean fiber are listed in Table.11.   

Table.11 electricity parameters of soybean fiber

  The comparison of antistatic property of soybean fiber and other fibers is shown in Table.12.

Table.12 The comparison of antistatic property

  According to table.12, it is obvious that the mass specific resistance of soybean fiber is similar with silk, and lower than other man-made fibers. It can be said that the soybean fiber has good antistatic effect, which is beneficial to the textile fabrication and wearing property.

6. Elastic property

  The crimp ratio, residual crimp ratio and elastic recovery rate of soybean fiber were tested, as illustrated in Table.13.

Table.13 The crimp ratio, residual crimp ratio and elastic recovery rate of soybean fiber

  Table.13 shows that the crimp ratio of soybean fiber is only 1.65%, while the common value of other chemical fiber is 10~15%. Therefore the cohesion force of soybean fiber is rather small and anti-slipping agent is necessary in spinning. The residual crimp ratio is only 0.88%, while the common values of other chemical fibers are 10%, which means that the crimp of soybean fiber is easy to unwind and the crimp stability is poor. The elastic recovery rate of soybean fiber is 55.4%, which is also lower than the common values of other chemical fibers (70~80%). Therefore the elastic property of soybean fiber is poor.

7. Light fastness property

  The light fastness of soybean fiber was tested under outdoor condition for two months. After the test, the color of soybean fiber fades a little, the strength decreases 11% and no mold fungus appears. Furthermore, the strength of soybean fiber decreases only 9.8% under the ultraviolet irradiation for 120 hours. The test results indicate that the soybean fiber has good light fastness property and good resistance to ultraviolet radiation, which is better than cotton, viscose and silk. 

8. Heat resistance property

  The shrinkage rates of soybean fiber in boiling water and dry heat air are listed in Table.14.  

Table.14 The shrinkage rate of soybean fiber in boiling water and dry heat air

  The test result indicates that the heat shrinkage rate of soybean fiber is rather great, and soybean fiber has no obvious melting point. The fiber strength decreases largely, and the color becomes  pale yellow at 160℃; and at 200℃, the color becomes deep yellow; at 300℃, the fiber begins to carbonize, and the color becomes brown. Therefore the temperatures of dyeing and setting of soybean fabric are preferred not to exceed 100℃. If the setting temperature is 110℃, the fabric handle becomes hard. At this time, the fabric handle can only be improved by the washing of soap bath above 60℃.   

9. Resistance properties to alkali, acid, moth and fungus

  The resistance properties of soybean fiber, wool, silk and cotton were tested and compared, as illustrated in Table.15.

Table.15 Chemical properties of soybean fiber, wool, silk and cotton

  Table.15 indicates that the resistance properties to alkali and acid of soybean fiber are the same as those of wool and silk. The resistance to fungus of soybean fiber is also the same as that of wool and silk. And the resistance to moth of soybean fiber is better than that of silk, wool and cotton. 

10. Dyeing property

  The dyeing property of soybean knitted fabric with different kinds of dyes were tested and compared, as listed in Table.16.    

Table.16 dyeing property of soybean knitted fabric with different kinds of dyes

Notes: the level is evaluated with five-grade standards: grade 5 is the best and grade 1 is the worst.

  The test results of Table.16 indicate that the dyeing property of soybean fiber with neutral dyes is relatively bad (the level is low and penetration property is also bad). Therefore, the application of neutral dyes to soybean fiber must be cautious. The weak-acid dyes, reactive dyes and substantive dyes are suitable for soybean fiber, while due to the low color fastness to washing, the substantive dyes are usually not used to soybean fiber except very few colors. The dying fastness on soybean fiber is similar to wool with different dyes.

11. Sanitarian property and content of amino acid

  The soybean protein contains lots of polar amino acids necessary for human-body, such as hydroxyl, amido-cyanogen and carboxyl. The content of parts of amino acids is listed in Table.17.

                       Table.17 the content of amino-acids (mg·g ^-1 protein)

  It is obvious that the soybean fiber has good biocompatibility and is beneficial to the human health. Furthermore, the anti-bacterial agents, which were added to the soybean fiber in spinning process, can restrain the growth of colon bacillus, impetigo bacterial and sporothrix. Therefore, soybean fiber is a kind of sanitarian fiber.

12. Wash ability

  Several knitted and woven soybean-fabric samples were laundered in the standard conditions. The test results indicate that the soybean fabric can be machine-washed, while the knitted samples shrink markedly after washing.