Standard Drafting Of A Adhesion Pull-out Method For Evaluating Film Fastness Of Nonwovens

Film-coated nonwovens are composed of nonwovens and polymer films,which are widely used in many fields,such as filtration and separation,medical and health,packaging,geotechnical construction and so on.The main function of the coated nonwovens is barrier and protection.because the film is generally very thin,the fastness of the film to the nonwovens affects the durability of the products,so the fastness is an important performance index to evaluate the quality of the coated nonwovens.However,the existing testing methods of film fastness of nonwovens are difficult to meet the emerging new film-coated nonwovens products,such as coated nonwovens,PTFE coated filter materials and so on.Due to the lack of a unified method to evaluate the fastness of film mulching,it may cause disputes,disrupt the market order,and is not conducive to the development of the industry.The purpose of this paper is to establish a widely applicable method for testing the film fastness of nonwovens.First of all,this study analyzes the existing test methods and standards of film-coated nonwovens,and finds out the limitations of stripping method and bubbling method.Based on the further analysis of the test and evaluation methods of color paint and film fastness,and referring to the principle of the test method,the viewpoint of using the pull-out method to evaluate the nonwoven coating fastness is put forward.By designing the sample maker(metal disc with clamp),exploring the clamping mode and selecting the type of double-sided glue,the experimental method of pull-out method was established.A total of 19 samples were collected,which are not suitable for the traditional testing methods of film fastness,including PTFE coated filter media,medical and health coated nonwovens,packaging coated nonwovens,etc.,and the effects of key test parameters such as adhesion area,tensile speed and pressing time on the test results were studied.The test results show that the acrylic pressure-sensitive double-sided adhesive with 16-30N/24 mm viscosity can be used for testing.After the test,there are different forms of film coating separation,which are tear separation type(film coating is torn and glued),bubbling separation type(film coating and base cloth forming bubbling),adhesion failure type(film coating and double-sided adhesive peeling)and so on.For the first two types,specific adhesion data can be obtained,and for the latter type,the adhesion force is determined to be greater than the test value.For the key experimental parameters:(1)the adhesion strength increases with the increase of adhesion area,but has no significant effect on the adhesion strength,(2)the tensile speed has no obvious effect on the results in a certain range,but excessive tensile speed will increase the volatility of the results(CV).(3)the increase of double-sided adhesive pressing time can give full play to the viscous properties of double-sided adhesive.For tear separation and bubble separation samples,pressing time increases the bubbling area,but has no obvious effect on the test results.The optimum test parameters are disc diameter 3mm(adhesion area),tensile speed 100 mm ·min-1 and doublesided adhesive pressing time 30-60 s.The adhesion measured by the pull-off method has strong applicability to the products such as PTFE film-coated filter material,medical and health filmcoated nonwovens,packaging film-coated nonwovens,etc.,and the test results of each sample have lower CV value and higher stability and repeatability;compared with the traditional stripping method,the pull-off method is more convenient in result processing,convenient and practical in operation.