PROCESS TO MANUFACTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCTS

Abstract: Patent of invention of a process to manufacture articles in expanded reticular polymeric materials and the resulting product in which a premolding process of the polymeric material antecedes to a reticulation and expansion process providing the possibility of production of polymeric material in more than one color, density and hardness through the connected vulcanization of the premolded pieces.

Description: Descriptive report of patent of invention of a "PROCESS TO MANUFACTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCTS". It is a process through which we can get goods in a polymeric material in one or more colors, in one or in different hardnesses, as well as one or more densites, where the material passes along a pre-molding fase and another that is a reticulation fase, these fases are independent but provide the exact placement of the different colors, densites and hardnesses in the final product. Nowadays in order to get pieces in polymeric material with different colors, hardness and density it is necessary to put together the parts when they are ready using a gluing process taking the risk of ungluing (separating) besides the production costs. Another technique that is used referring to colors is painting. As soon as the piece is ready its external faces are painted according to what is desired. Although, in this case, it avoids ungluing, it does not avoid costs with the painting process and the inherent losses. Besides, according to the material, painting is not very proper to the visual effect. On the other hand, through the present techniques there is no way to inject E.V.A. compound to obtain different densites and hardness in the same object, as the operation of injection and reticulation happens sequentially at the same matrix. It is also used a process of superposition of layers, it is blades of the compound for later connected reticulation. In this case the colors are always parallel and in superposed layers. At last, to get more than one color, there is the possibility of mixing the "pellets" of many colors. In this case, a product where the colors distribution happens aleatoryly, without possibility of control is gotten This invention constitutes a process through which we can reach different hardness, densites and colors, with perfect control in its distribution in the final product. In the first step of the process we pre-mold the compound of polymeric material (E.V.A.) of each one of the pieces that form the final product. Each piece can have, one color, one density and one hardness all of them pre-determined. In the second step the pre-molded pieces will be incased and placed in a way to form the group to be submitted to connected reticulation. It is also part of this invention the final product gotten with this process. A better description of this invention is accomplished with support of the figures, where: Figure l shows the pre-molded pieces (1) , (2), (3), (4) and (5) to make an inner sole of a sports shoe. Figure 2 shows the inner sole ready and the pieces (1), (2), (3), (4) and (5) together through reticulation and the figure indicates that (1) is a color with 48 shore a hardness, (2) the second color with 25 shore a hardness and (3), (4) and (5) represent the third color with 45 shore a hardeness. Figure 3 shows the pre-molded parts (6) , (7) , (8) and (9) of a sole of sandal and slipper where the following characteristics were demanded: 3 colors with unique density and hardness. Figure 4 shows the sole when it is ready with the pieces (6), (7), (8) and (9) already together by reticulation permitting to observe that the joints of the pieces present a homogeneous texture, and total definition of colors, showing on the drawing by (6) the first color, (7) and (9) the second color and finally (8) the third color. The process starts with the formation of the compound of polymeric material to be used in each one of the parts that will form the final product, and this compound will have its characteristics, color, density and hardness demanded in each part. Once defined the compound of polymeric material, also known as E.V.A., in its color, density and hardness we seek, through the injection process, extrusion or any other way, to plastify the E.V.A. compound in such temperature that allows the pre¬ molding in closed mold. The temperature in the pre¬ molding process, cannot surpass the point in which the expander agent, and the reticulating agent start to react and that is between 95 and 105 Celsius degrees. In this called first step of the process, where we pre-mold the E.V.A. compound it is necessary to observe some caution to, in a second fase, get constant results, because any difference in the pre¬ molding process will cause differences in the final product. The mold to pre-form the pieces, should be in a constant temperature of 45 Celsius degrees, and that also has air exits, in specific places, to avoid the compound to copy the mold details perfectly. Every time that the pre-molded pieces get out of the mold it is necessary to put immediately in a water deposit with temperature between 40 and 50 Celsius degrees for at least 3 minutes, after this time put in a continuous tunel to take out the humidity of the parts in a temperature of 30 Celsius degrees. Finisshed the first step with the pre-molded pieces ready to the next fase, it is necessary to process them in the maximum time of 24 hours in order to keep the compound to be reticulated in the second step, inaltered. In the case of short of equipment to process all the pre-molded pieces, these must be placed in vacuous closed packing and kept in j a place without light and with a temperature of maximum 15 Celsius degrees. So we can keep inaltered the compound characteristics until 30 days after the initial process. The second step of the process consists in setting the pre-molded pieces in only one group, and later put them in mold specially prepared to reticulate and expand through the compression in press of quick open process. The mold where the parts are put for later reticulation and expansion, must be made with vacuous chamber, or make the vacuous chamber out of the mold, to get to take it out before its total closing, the air that occasionally gets in, reaching the desired finishing without fails on the final product surface. The volume of the group must be equal to the cavity of the mold, where it shoul be reticulated in a temperature that varied from 150 to 180 Celsius degrees, and during the necessary time according to thickness and characteristics desired. Once gotten the final product, this is submitted, immediately, to a cooling process accomplished by a movable belt which puts the part coming from the matrix of reticulation in a channel where there are many water deposits in different temperatures. The cooling operation happens sequentially, starting with a temperature of 99°C, 77°C, 50°C and 30°C, in periods of approximately four minutes. After this process, the pieces pass through a tunel of forced ventilation, with air in a temperature around 25°C to get dry. In this reticulation process we use all the ways already known, as the temperature control, as time control as well as the pressure of press closing. The reticulation has the function besides giving to the piece its final size, expanded, to provide the linking of many parts to get the final piece. So, the reticulation puts together each of the parts with different colors, densites and hardnesses, that form the final product as we can see on figures 2 and 4. We can notice on figure 2 that the color expanded reticulated polymeric material, is perfectly limited to the pre-defined areas accomplished by the pre-molds. By this process we can give to the final product a better appearance than to those that had the printing process and better resistance than those that had the gluing process. This process still allows, giving to the final product as many densities and hardnesses as the necessary pre-molds to form the final product, providing, if it is the demand, a sole, for example, with two different hardnesses and densites.

Claims: Claims 1."PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCT" characterized by two fases, the first one, the pre-molding of the polymeric material before the reticulation, and the second one, the reticulation. 2."PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCT" according to claim l, characterized by a first fase in which the polymeric material is submitted to pre-molding at a temperature lower to the one in which the expander and reticulation agents become active. 3."PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCT" according to claim 2, characterized by the separated molding of each of the pre-molds of the final group that have diferent colors, densities and hardness. 4."PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCT" according to claim 1, characterized by the connected reticulation of the pre-molds. 5. "PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCT" according to claim 4, characterized by the connected reticulation of the pre-molds of different colors, densities or hardnesses that form the final group. 6."PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS AND THE RESULTING PRODUCT" according to claim 5, characterized by mold where the pieces are put for later reticulation and expansion, not having air inside at the moment of reticulation. 7."PRODUCT OBTAINED THROUGH A PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS" characterized by a first fase of the pre¬ molding and a second fase of reticulation. 8."PRODUCT OBTAINED THROUGH A PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS" according to claim 6, characterized by having, at least two pieces linked by the reticulation process. 9."PRODUCT OBTAINED THROUGH A PROCESS TO MANUFECTURE ARTICLES IN EXPANDED RETICULAR POLYMERIC MATERIALS" characterized by having at least two colors, densities and or hardnesses resulting from different polymeric matirial compond used in the pre-mold.

Inventors: OLIVER SILVA REYNALDO OSCAR, OLIVER SILVA, REYNALDO, OSCAR
Applicants: OLIVER SILVA REYNALDO OSCAR, OLIVER SILVA, REYNALDO, OSCAR
Application year: 1995
Main classification: B29C69
IPC codes: B29B11, B29C43, B29C44, B29C67, B29D31