Technical Field of the Invention

The invention relates to artificial leather and its production method developed for use in clothing, upholstery, footwear, medical, and automotive products.

State of the Art

Today, PVC artificial leather produced with standard formulas and methods has no air permeability. PVC artificial leather with air permeability is generally produced by mechanical puncturing. This situation causes a decrease in the strength of the artificial leather. The pores that provide breathing are visible and disrupt the visuality in the samples developed without mechanical intervention. In addition, a wide variety of chemical materials are used in the development of these products.

PVC artificial leather production is currently carried out using PVC, plasticizer, pigment, and stabilizer worldwide in the current art. Filling material options may vary. It is not usual to use water in artificial leather production; it is even thought that water disrupts the structure of plastisol and causes deformations on the surface after coating. Producers refrain from using water for any purpose at any stage of production for this reason. Instead, either mechanical puncturing processes that disrupt the strength of the material are preferred in production, or chemicals and solvents that may be harmful to the environment, human health, and nature are used in order to ensure air permeability.

In the literature, the application titled “A method for making breathable film” based on polyvinyl chloride (PVC) with the number EP2918629 has been found. This method includes the steps of preparing a pasty composition, applying this composition to a support, gelling and drying the pasty composition applied to the support with the help of heat, and obtaining a compact film in a foam-free structure. A PVC based film is obtained as a result, which comprises pores with an average pore diameter of 1 pm to 1 mm from one surface to the other surface, has a gas permeability between 0.1 and 200 and a water vapor permeability in the range of 0.1 to 200 mg cm ^-2 .hour ¹ . The pasty composition in the said method is obtained by mixing fractions comprising PVC as the first fraction, polyether-, polyester- or polycarbonate-polyurethanes as the second fraction, or a waterbased dispersion of mixtures thereof, and fractions comprising auxiliaries and adjuvants as the third fraction. There is a pasty structure obtained without adding an organic solvent except water. However, extra chemicals are added as impurities to ensure breathability. Breathability and porous structure were not built using only water, even though water use is included here. In addition, the pores of the product obtained here are visible. The process steps of this document completely differ according to the subject of the invention. It is stated in W02007030904A1 that at least 1 type of polyelectrolyte is used together with water to develop breathable material, unlike the subject of the invention. However, no materials or chemicals other than water were used in addition to the standard PVC artificial leather components in the subject of the invention. And the fact that the water used is pure, recycled, salty, etc. does not pose any problem. The other main differences of the invention are that the pores obtained on the product by providing the evaporation of the water used in the correct ratio and order in the formula with the determined parameters are further increased by the vacuum embossing process and thus the air permeability is at least doubled. Here, it is not mentioned to obtain a pattern with the vacuum embossing method and to heat the coating as stages. It is thought as a result that the subject of the invention contains innovation in the face of this document.

As a result, in order to solve the abovementioned problems and the insufficiency of the current solutions makes it necessary to make a development in the relevant technical field.

Brief Description of the Invention

The present invention relates to an artificial leather and its production method that meets the aforementioned needs and eliminates all the disadvantages and provides advantages thereof.

The primary object of the invention is to develop an artificial leather with a formulation that provides air permeability and breathability, and its production method.

An object of the invention is to develop a method of production artificial leather, which does not mechanically involve post-puncturing, thus does not create a loss of strength in the product.

Another object of the invention is to develop a method of artificial leather production that does not involve the use of a wide range of chemicals and the formation of visible pores that may visually disturb the end user.

The artificial leather subject to the invention includes PVC, plasticizer, stabilizer, and filler as artificial leather components, as well as water without the need to use an additional chemical to ensure porous structure, air permeability and breathability, and the production method subject to the invention includes the steps of preparing plastisol and forming a homogeneous mixture, adding water before coating, homogeneous distribution of the added water in plastisol, transfer coating on paper, enlarging and increasing the pores formed in the coating process during the designing process with vacuum embossing process in order to fulfill the above-mentioned objects.

The structural and characteristic features of the present invention will be understood clearly by the following detailed description and therefore the evaluation shall be made by taking the detailed description into consideration.

Detailed Description of the Invention

The artificial leather subject matter of the invention and its production method are described only for clarifying the subject matter in a manner such that it creates no limiting effect in this detailed description.

The artificial leather subject to the invention is basically produced with a formulation that provides air permeability and breathability. This formulation contains powder emulsion or micro suspension PVC, plasticizer, stabilizer, filler, and H2O. Here, CaCOs in the form of powder can be preferred as filler. Furthermore, the subject of the invention may also comprise pigment in a preferred embodiment. All PVC and plasticizer types can be used in the formulation. All organic or inorganic pigments can be used as pigments. All heat and light stabilizers developed for PVC can be used. The fabric can be laminated with the transfer coating method to the film made with the specified formulation or direct coating can be made on the fabric with a suitable machine where knife stripping can be performed. Cotton, visco, polyamide or polyester or a mixture thereof can be used if fabric is used. In addition, the fabric used can be woven or knitted. In addition to CaCO3, other fillers may also be used. In addition, a flame retardant additive can be added to the formulation. The paper used during transfer coating can be plain or patterned. Lacquer application can be performed to improve or change the surface performance of the product between transfer coating and vacuum embossing processes. This lacquer can be acrylic, polyester or polycarbonate based. The amounts by weight of the components constituting the subject of the invention are presented in Table 1 .

Table 1. Quantities by weight of the inventive components as a percentage

The greatest innovation in the invention is that a wide variety of chemicals are not used in the formulation according to the present art. The subject of the invention is obtained by adding only a certain amount of water, which is the most harmless chemical in a certain order, in addition to the formula we developed consisting of basic PVC artificial leather components. The water evaporated during the temperature gelation of PVC and plastisol creates micro gaps and the gelation takes place around these gaps as a result of the parameters designed by adding water. Air permeability and high breathing ability are ensured in this way. The amount of CaCOs in it and the structural incompatibility (insolubility) of water with plastisol are the most important parameters in developing the product.

The production method of the artificial leather subject to the invention basically includes the steps of preparing plastisol, forming a homogeneous mixture, adding water before coating, homogeneous distribution of the added water in plastisol, transfer coating on paper, enlarging and increasing the pores formed in the coating process during the designing process with vacuum embossing process.

PVC, plasticizer, stabilizer, and filler are mixed in the proportions selected in accordance with Table 1 for the preparation of plastisol. CaCOs is used as filler in this step and pigment is also added to the mixture in a preferred embodiment. The trivalent system can be used for this prepared plastisol to reach a more homogeneous structure. An appropriate amount of water is added to the plastisol in accordance with the ratios specified in Table 1 and distributed in the plastisol with the help of a mixer after the plastisol is prepared. Water is preferred at ambient temperature, and all kinds of water such as tap water, drinking water, treatment water, salt mineral water can be used. Mixer speed is preferred in the range of 50-2500 rpm. Transfer coating is applied in certain parameters after the water is distributed homogeneously in plastisol. A patterned transfer paper or transfer paper without a pattern can be selected for the transfer coating. Coating temperatures are an important parameter for smooth and invisible micro pores. The compartments in all furnaces are gradually adjusted between temperatures of 80-2200 for regul ar evaporation of the water added in the previous step. The temperature must be gradually adjusted in the range of 120 to 2000 in the coating compartments. The temperature for the coating is selected in the range of 80 to 2000 in the first furnace and 80 to 2200 in the second, third, and fourth furnaces. This gradual heat increase is critical to maintain the gaps created by water that starts to evaporate just before gelation. The coating line speed can be in the range of 5 to 30 Im/min. The film weight of this product can be in the range of 50 g/m ² to 1000 g/m ² .

This product consisting of one to five, preferably three, layers have a film weight in the range of about 580±50 g/m ² in some preferred embodiments. The single layer product is a PVC based layer formed with the specified formulation. Transfers on paper are repeated for each layer in order to obtain a multilayer product. The subject of the invention may also include fabric as the last layer. There is at least two-layer structure, at least one of which is PVC based in this case. If the use of fabric is preferred, the fabric is laminated with the previous layers in the last layer or with the first layers with the transfer coating method or direct coating is made on the fabric with a suitable machine where knife stripping can be performed. This fabric can be preferred as cotton, polyester, viscose or a mixture thereof, woven or knitted. The product, which comes out of the coating in a micro porous state, is shaped with patterned vacuum cylinders immediately after being heated and softened from the upper surface with infrared heaters between 140 and 220‘C with a vacuum embossing system. The vacuum embossing heating temperature for the embossing roll used to heat the bottom surface of the artificial leather can be in the range of 0-210'C. The temperature therein is selected in the range 110-2000 in a preferred embodiment. The vacuum embossing heating temperature is selected in the range of 140-2200 for infrared. The vacuum strength is preferred in the range of 10-75 cm Hg and the embossing line speed is preferred in the range of 3-25 Im /min. The fully formed micro pores grow in the coating and the semi-occurring pore-like structures are opened in this step. In short, the pores formed in the coating are enlarged and multiplied in an invisible way in the designing step with the vacuum embossing process. Thus, the air permeability and breathability properties of the material increase. This process does not cause loss of strength as in mechanical puncturing since there is no loss of material here. Deformations can be seen on the surface in the coating made with high temperature. Deformation or non-porous structure may occur on the surface if the water is not added in the right order and in the right amount. Deformation or non-porous structure can be observed on the surface if the water is not distributed homogeneously in plastisol. The water in the mixture may not evaporate when the mixing rate is very high. Accordingly, problems such as non-porous structure and moist product may arise. Too fast coating tour may cause deformation or non-porous structure on the surface. The gelation may not take place if the temperatures are too low. Otherwise, the formed pores may be closed if it is too high. Pores can be closed at high temperatures; and low temperatures can make pattern achievement difficult in the embossing step. Low vacuum strength does not affect the number and size of pores very much. The use of CaCOs, which is preferred as a filler in the formulation, less than necessary may cause the number of pores to decrease, and the use of the product too much may prevent gelification. In short, it is critical that the parameters in each step are set correctly in order to obtain the final product as desired.

The water, which is subsequently homogeneously distributed in the plastisol prepared with the formulation developed in the subject of the invention, creates micro pores thanks to its evaporation after the incompatibility it creates when it is produced with the designed parameters. The most advantageous aspect of these micro pores prevents any structural instability as a result of the fact that the gelification can take place fully around the water in the plastisol. Additionally, the filler material was determined as CaCOs in a preferred embodiment. The reason for this is that the interaction of CaCOs with water in plastisol has been observed to increase air permeability. There are no pores formed by mechanical puncturing in the subject of the invention. Accordingly, there is no loss of strength in the final product. The final product with invisible micro pores does not visually disturb the end user. The vacuum embossing method was used to provide an even higher breathing ability of the air-permeable product after coating. It has been discovered by heating the micro porous coating made in this process that the pores have grown after vacuum shaping and the air permeability feature has increased at least 2 times. Artificial leather with invisible micro pores and much more air permeability than real leather used in the market has been developed in this way. In addition, the number and size of pores increased by the vacuum embossing method are not visible even after the process and preserve the appearance that is not comfortable for the end user. In addition, the use of the vacuum embossing method provides unlimited options as a pattern. In the artificial leather formulation developed in this way, which has higher air permeability than real leather, compared to the examples in the world, both less chemical components are used and it does not contain any solvents that are harmful to health, and at the same time, a low-cost product has been developed that is sensitive to human health and the environment. This provides a healthier and more comfortable product to the end user by increasing market share and competitiveness.