Technical Field

The invention comprises the development of an interface polymeric material which achieves the adhesion of the layers if desired and non-adhesion of the layers if desired in polymeric structures which have the same or similar chemical compatibility and structure, with two or more layers, and again; the adhesion of the interface to a layer whereas the interface does not adhere to the other layer in polymeric structures which have more than two layers, if desired. Developing quality products is aimed by means of the adhesive selectivity needed during the processing of polymeric structures. Especially, it is aimed eliminating the use of talcum (powder) which is being used with the purpose of providing non-adhesion in the cable industry by means of the above subject interface structure developed.

Prior Art

Application of multi-layered polymeric structures is fairly common in the industry. Especially the film or the cable industry is sectors where the multi-layer polymeric applications are widely used. In these and similar sectors, the polymeric materials whose chemical structures have the same or similar properties are used in multi-layers. In these multi-layer structures, depending on the application area, in some cases while adhesion is desired between the polymeric layers, it is not desired with a different layer at the same time.

Figure 1: The Adhesion/Non- Adhesion Property Desired in Multi-Layer Structures

For example, in Figure 1 , while a strong adhesion or structural integrity between the L1 and L2 layers is desired in the three-layer structure shown, a rather strong phase separation and non adhesion is sought between the L2 and L3 layers.

The above three-layered structures have the same or similar chemical composition but yet the interactions between them are desired to be different. One of the best examples of this case is seen in the cable industry.

Figure 2: The View of the Multi-Layer Polymeric Structures in the Multi-Core

and Single-Core Cable Structure

Above in Figure 2, the location and physical settlement of the polymeric structures with respect to each other in the multi-core and single-core cable structure is illustrated. While the conductive copper and its location is shown by the letter C, polymeric structures having three different structures take place as illustrated by L1 , L2 and L3. L3 is the layer which contacts the copper and which is in the innermost structure. L2 has the same chemical structure with L3 and comprises color pigments within its structure as distinct from L3. In this way, the ease of use and segregation of the cores is provided in the multi-core structures. L1 is the material which constitutes the topmost structure of the cable named as the sheath. In the above cable configuration, since L2 and L3 have the same material structure and are designed for the same purpose, a strong adhesion is desired between these two layers. On the other hand, even though the sheathing layer shown as L1 has the same or similar structure chemically, no adhesion is desired between the layers L1 and L2 because it is crucial that the sheathing layer should be strippable in the stage of final use; hence the cable can be applied with ease. In present applications, a strong tendency to adhere exists between both layers since the L1 and L2 layers have the same chemical structures. For this reason, with the purpose of preventing adhesion in cable applications, a layer composed of an inorganic material (talcum) is formed by means of the electrostatic effect between the L1 and L2 layers as an additional procedure and the non-adhesion effect is attempted to be achieved by preventing the interaction between the L1 and L2 layers.

Flowever, there are certain disadvantages of the Talcum (Powder) application. These can be listed as;

• Creating a requirement for additional equipment and machinery, • Necessity of additional material use,

• Increasing the cable diameter,

• Increasing the consumption and cost of the sheathing material due to the increased cable diameter,

• Continuance of the homogeneity problem in talcum application and therefore, the tendency to adhere partially,

• Encountering problems with application during talcum application in humid air,

• The hazards of talcum on human health and therefore, the increasing limitations on its use within the frame of occupational health and safety regulations,

• Since the colored L2 layer is covered with powder, the powder causing dust-related errors in the automatic cable end opening machines,

• The presence of the powder posing an obstacle for the color sensor to function in the automatic cable end opening machines

• The presence of the powder bringing additional maintenance costs for automatic cable end opening,

• The presence of the powder causing additional cleaning operations at the application and processing stages of the cable,

• The presence of the powder in the cable structure causing the presence of a troublesome dust source for the companies producing electronic devices and thus causing production and quality losses.

The L2 layer developed by means of the invention of this patent study adheres to the L1 layer without needing any additional material and machinery requirement and the L2 layer has the characteristic of not adhering to the L3 layer without the need of using a material such as powder, etc. Thus, the elimination of the additional materials and processes used in the wire, film and the like sectors will be realized and the cost and quality-driven products and production processes will be obtained.

Figures Illustrating the Invention

Figure 1 : The Adhesion/Non-Adhesion Property Desired in Multi-Layer Structures

Figure 2: The View of the Multi-Layer Polymeric Structures in the Multi-Core and Single- Core Cable Structure

Figure 3: The Effect of Block Copolymer Use on Adhesion

Figure 4: The Effect of Impregnated Copolymer Use on the Adhesion/Non-Adhesion Description of the Invention

The invention and method mentioned within the scope of this invention is obtaining multi-layer polymeric structures having the desired structure by means of bringing adhesion/non-adhesion properties merely by the modification of the polymeric structure which has the same chemical structure, without needing any material and/or machine equipment.

With a simple approach, adhesion between two polymeric layers can be defined as the formation of a new single phase by the removal of the interface between two layers by means of realizing a cross-layer diffusion of the polymer chains which take place on different layers. On the other hand, the non-adhesion can be defined as the presence of two separate layers which do not meld by means of preventing the diffusion of the polymer chains at the interface formed by the two polymer layers.

In the light of the above data, while the polymer chains are desired to be diffused into the other layer by passing through the interface, for the interfaces in which the adhesion is desired, the requirement for preventing diffusion of the polymer chains comes forth for the interfaces in the cases in which adhesion is not desired.

The selectivity of the diffusion characteristics of polymeric structures is determined by the chemical compatibility of the polymeric structures which takes place in the polymeric structures used in different layers.

In other words, while the polymer chains, which take place on different layers at the interface in which the adhesion phenomenon is desired, need to be chemically compatible with each other, the polymeric structures, which take place on different layers at the interface in which the adhesion is not desired need to be chemically incompatible with each other.

In this direction, whereas adhesion is desired between L2 and L3 within the structure shown in Figure 2, cross-layer polymer diffusion and chemical compatibility is sought between these two layers. On the other hand, due to the expectation of non-adhesion between the L2 and L1 layers, phase separation and therefore, chemical incompatibility is sought between the L1 and L2. In the case in which each of the three layers L1 , L2 and L3 are products on the same polymer base, the modification of the L2 interface comes to hand as the method developed within the scope of this patent. The use of the copolymers of the L2 layer base polymers is presented as a solution by the patent writers and the solutions used within the scope of the patent are listed in the following.

• Use of block copolymers

Figure 4: The Effect of Block Copolymer Use on Adhesion

By the use of the block copolymer, adhesion/non-adhesion properties between the layers can be determined. In this case, the block copolymer of the base polymer used in the L2 layer and the L1 and L3 layers is used alone or by mixing with the base polymer at various proportions. The important requirement in this application is that one of the blocks of the block copolymer is compatible with the base polymer (Z) and the other block is incompatible with the base polymer (Y). In this case, the application of the L2 and L3 layers is realized in initially. By this means, since the compatible block (Z) in the block copolymer is compatible with the base polymer (X), it is positioned as in Figure 3. In other words, the compatible block of the block copolymer forms an interface with the base polymer and allows for polymer diffusion due to the chemical compatibility. Thus, the desired adhesion phenomenon is obtained. On the other hand, the incompatible block (Y) of the block copolymer is positioned so as to be away from the base polymer in the L3 layer . It means that it is positioned at the interface which the L2 layer and the L1 layer will form.

With the application of the L2 layer and the L1 layer, the base polymer (X) in the L1 layer and the incompatible (Y) block in the L2 layer form a new interface. The polymer diffusion does not take place at the interface formed by the base polymer (X) and the incompatible (Y) block and thus, the non-adhesion phenomenon is obtained between the L1 and L2 layers.

· Use of the graft copolymer

Figure 5: The Effect of Engrafted Copolymer Use on Adhesion/Non -Adhesion One of the inventions and methods developed in order to manage the adhesion and non adhesion phenomena in the multi-layer polymeric structures within the scope of the patent is switching the full extent or a part of the polymer chains in the polymeric layers with graft copolymers or engrafting the monomeric and/or polymeric structures having a different chemical structure to the structure of the full extent or a part of the polymers/base polymers in the layers. For example, whereas in the settlement of the multi-layer polymeric structures as in Figure 4 non-adhesion is desired between the L1 and L2 layers, in the case that adhesion is required between the L2 and L3 layers, the subject requirements can be fulfilled with graft copolymer addition to the L2 layer polymeric structure or modification of the structure to the graft copolymer. The main chain (Z) of the graft copolymer used with this purpose should be the base polymer itself or another polymer compatible with the base polymer. In addition, the monomer and/or polymer (Y) engrafted on the main chain (Z) should be chemically incompatible with the base polymer (X). The adhesion property required between the L2 and L3 layers mentioned within the scope of the invention will be possible by means of the polymer diffusion to be realized between the L2 and L3 layers due to the chemical compatibility between the base polymer (X) and the engrafted copolymer main chain (Z) compatible with the base polymer. The engrafted monomer/polymer chain (Y) chemically incompatible as a result of the priority application of the L2 and L3 layers is positioned in the direction of the interface the L1 and L2 layers will form due to the presence of the base polymer in the L3 layer. Therefore, when the L1 layer which has the same base polymer forms the interface with the L2 layer, the base polymers (X) in the L1 layer meet the surface formed by the chemically incompatible engrafted monomer/polymer chains (Y) in the L2 layer. Due to the fact that the two polymers which are chemically incompatible in both of the layers cannot create diffusion by passing through the interface, the required non-adhesion phenomenon is obtained.