Mikro gözenekli polipropilen nefes alabilen film üretimi

Polymeric structures that pass water vapor and air, but exhibit barrier properties against liquids are called breathable films. Breathable films, that find new uses in the direction of evolving and changing living standards, can be grouped under two main types; monolithic and microporous. In addition to monolithic structures that inherently breathe, microporous structures are obtained by the addition of inorganic fillers to the polyolefin matrix. Stretching this filler loaded polyolefin matrix creates the micro pores and achives the breathability. Microporous breathable films potentially capable of creating new markets because of their low cost and usefulness. They are widely used in many industries, especially hygienic products (baby diapers, single wraps, patient gowns), construction materials (roof insulation, wall insulation) and personal protective clothing. A standard microporous polyolefin, - generally polyethylene-, mineral filler breathable film contains billions of micropores. The mineral fillers are active ingredients which give the film unique features enabling it to breathe through the network of micropores. The hydrophobic nature of the filler is a desirable feature as it will reduce water retention during production processes. Examples of the inorganic filler include calcium carbonate, talc, clay, kaolin, silica, magnesium carbonate, magnesium sulfate, calcium sulfate, aluminum hydroxide, zinc oxide, zeolite. The filling rate to the polyolefin matrix usually varies between 10-70%. Breathable films are used in backsheets, for example as a backsheet component laminated to a nonwoven and/or other layers. They are used in many of today's personal care absorbent articles. Filled and stretched polyolefin films are making the diapers more comfortable to the wearer since they provide good water vapor transmission. With the using laminates of breathable films and nonwoven webs, the relative humidity and temperature within the personal care products can be reduced. The breathable films themselves provide vapor breathability and liquid barrier, but are typically not strong enough to be used alone. The nonwoven webs provide strength as well as fabric-like properties to the laminates. To making a polymeric film vapor permeable, includes mixing a matrix polymer with the inorganic filler via double-screw compound extrusion process. The resulting mixture is using to produce monolayer or multilayer film via cast or blown extrusion process. Then, the film is heated and stretched, causing voids to form in the areas surrounding the filler particles via stretching unit. The aim of this thesis is to use polypropylene matrix instead of the classicized polyethylene matrix used in the production of microporous breathable films. As the inorganic filler, surface-modified calcium carbonate is preferred. The use of polypropylene matrix in microporous film will ensure a more consistent structure since used laminates are generally made from polypropylene. This compliant construction is expected to reduce the use of glue and improve process difficulty such as reduce the differences of melting point of films and laminates in the lamination process. Moreover, it is one of today's needs to obtain films with high strength that will not be laminated and used as a single layer. In the first step of the thesis study, polypropylene based two different compounds that contained 50% (C1) and 60% (C2) of surface modified calcium carbonate were prepared in a twin screw extruder. The motor speed was 600 rpm during the compounding process and the reverse temperature profile was prefered. In the second stage, the experimental design was planned for the samples obtained by the blown film extrusion method and the variable parameters were determined. In terms of experimental design, weight, width, and stretching ratio were accepted as constant parameters. The ratio of linear low density polyethylene to be used during the blown film extrusion process and the two prepared compounds (C1 and C2) were determined as variable parameters. In this direction, it was planned to obtain four film samples (BF1, BF2, BF3 and BF4) with 0% and 15% of linear low density polyethylene added to C1 and C2 compounds. At the last stage, the micropores were obtained by using the stretching unit to achive breathability. MDO (Machine Direction Orientation) unit was used as the stretching unit with the 1:4 stretching ratio. Temperatures of the preheating, stretching, annealing and cooling rollers in the MDO unit were determined in terms of material structure and kept constant throughout production. In the study, a commercial polypropylene and polyethylene based compounds were characterized and compared with the prepared compounds, C1 and C2. The DSC, FTIR and ash analysis were investigated according to the material structure of the compounds. Increasing the amount of calcium carbonate in the compound has been found to increase the melt flow rate and density. Linear low density polyethylene can be added to improve the processability of the polypropylene based compounds. The obtained film samples were analyzed with the DSC, FTIR, ash tester, melt flow rate tester and density tester. The thermal characteristics and the IR absorption peaks of the film samples were determined. As a result of the ash analysis, the ratio of inorganic filler in the film matrix, namely calcium carbonate, was determined. The effect of the ratio of calcium carbonate contained in the film samples on the melt flow rate and density values was observed by analysis. A polyethylene based commercial microporous film was analyzed comparatively with BF1, BF2 and BF4 film samples for mechanical properties such as tensile strength at break, tensile strength, elastic modulus and tear strength. As the polypropylene is more rigid, it has been found that the tensile strengths and elastic modulus of the film samples are higher than commercial microporous polyethylene breathable film sample. Tensile elongation at break of the film samples are lower than commercial microporous polyethylene breathable film sample. It has been found that the tear strength values are rather low compared to the commercial microporous polyethylene breathable film sample. When the obtained film samples are compared within themselves, it is seen that the strength values change with the calcium carbonate ratio in the film matrix. Increase in the amount of calcium carbonate results in a decrease in strength values. The breathability (water vapor permeability), one of the most important parameters, was evaluated comparatively by using the MOCON analysis method. The water vapor permeability can be basically related to the material structure, the amount of calcium carbonate and the rate of stretching in the stretching unit. When the obtained film samples are compared within itself, it was found that water vapor permeability was proportional to the calcium carbonate ratio in the film matrix. BF1 and BF4 film specimens are particularly acceptable when compared with the commercial microporous polyethylene breathable film sample in terms of water vapor permeability. Within the scope of the thesis study, it is aimed to obtain micropores. For this reason, by using SEM analysis, surface morphology of the obtained film samples was examined and random micropores were observed at different sizes. It has been determined that the size of the micro pores in the vertical level is higher than the horizontal level. This is due to the fact that the vertical level exposed to more stress. It was seen that the stretching direction is vertical. The resulting microporous polypropylene breathable films can be used in the hygiene sector in terms of water vapor permeability values. More rigid materials were obtained compared to polyethylene based microporous film. It is known that the nature of the polypropylene structure is coming from the propylene monomers is more rigid than the polyethylene.