## 4 Conclusions  
Investigation of mechanical properties of two variants ultra-strong weft plain knits with and without elastomeric yarn in the structure, designed for personal protective equipment, showed dependence on structural parameters, which led to the following conclusions:  
* An increase in the loop length of the weft plain knits with elastomeric tuck-miss laid yarn has approx. four times higher influence on the decrease of the breaking force and increases the elongation at the break when compared to weft plain knits without elastomeric yarn.
* The increase of the loop length influenced higher cut resistance. However, this influence for plain knits with elastomeric yarn is approx. three times lower than for knits without the elastomeric yarn.
* Tearing force of all investigated fabrics varied in the ranges of 217-227 N irrespectively of the tearing direction, knitting structure and differences in loop length. Moreover, samples break in the area of sample parts clamped into the top and bottom clamps while the main part of the sample remains not damaged.
* A decrease of a loop length in 1 mm can determine approx. 33% higher resistance to puncture of both plain knit variants, with and without the elastomeric yarn in the structure. However, plain knitted fabrics without the elastomeric yarn are more puncture resistant than fleece fabrics with elastomeric yarn because of different deformation abilities during the puncture.
* Abrasion resistance of the plain structure knits decreases with increases in the loop length, as the looser structure of a knit is less resistant to abrasion. However, the increase of the loop length of plain knits with elastomeric tuck-miss laid yarn leads to the increase in the abrasion resistance as the elastomeric yarn results formation of the relief surface, the convex part of which is first subjected to abrasion upon contact with the abrasive surface.  
The results of this research show that elastomeric component has high influence on mechanical properties of knits and even more--it changes the principal mechanical behaviour of knits and character of structural parameters influence on the investigated properties. In the next stage of investigations, more variants of elastomeric yarn introduction into the knitted structure will be developed and mechanical and comfort properties of these knits will be analysed.  
Conceptualization, R.M., D.M. and L.H.; methodology, D.M., L.H. and S.B.; formal analysis, D.M., R.M. and L.H.; investigation, L.H., S.B. and T.I.; resources, L.H., S.B. and T.I.; data curation, D.M., and L.H.; writing--original draft preparation, D.M. and L.H.; writing--review and editing, R.M.; visualization, D.M. and L.H.; supervision, R.M. and L.H.; project administration, R.M. and L.H. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
This work was supported by the Lithuanian-Ukraine cooperation project \"Knitted Materials for Personal Protective Equipment against Mechanical and Flame Damages (PERPROKNIT)\" by the Research Council of Lithuania and Ministry of Education and Science of Ukraine.  
The authors declare no conflict of interest.