Patent Publication Number: US-2017348936-A1

Title: Automobiles weather strip structure and manufacturing method

Description:
TECHNICAL FIELD 
     The present invention relates to an automobile weather strip and a method for manufacturing the same, and more particularly, to an automobile weather strip and a method for manufacturing the same wherein the weather strip is made of an olefinic rubber or thermoplastic elastomer and a slip agent layer having low frictional resistance is formed on the surface of the weather strip. 
     BACKGROUND ART 
     Generally, a weather strip for an automobile is a rubber packing adapted to seal the interior and trunk room of the automobile to prevent external environmental materials such as external air, sound, dust, rain water, snow and so on from entering the interior of the automobile and also provided in such a manner as to allow a door, a body, a door channel, a trunk lid or the like to be installed along the edge thereof so that the impact occurring when the door is closed can be absorbed, and while the automobile is being driven, the generation of the vibrations in the trunk lid can be suppressed. 
     There are various kinds of weather strips such as a body weather strip, a door weather strip, a glass run weather strip, a trunk lid weather strip, a back door weather strip and the like, and they are installed on the spaces between a body side and a door frame, so that they absorb the impact occurring when the door is closed or prevent foreign matters from entering the interior of the automobile from the outside. 
     Conventional weather strips are made in such a manner as to allow a plastic slip agent to be extruded and co-extruded at the same time on the surface of a seal part. In this case, the slip agent has excellent durability, but since the slip agent is made of a hard material, a compressive load becomes high to cause some problems like surface fracture, thereby making it hard to commercialize the conventional weather strip. 
     On the other hand, a conventional weather strip as disclosed in Japanese Patent Application Laid-open No. 2004-149102 is configured wherein a super high hardness surface layer is provided, which is weak in permanent deformation, and multiple extrusion is needed, which is hard to control the multiple extrusion. Further, dust contamination caused by the static electricity on the surface becomes serious, and many problems happen in the treatment thereof, thereby making it hard to commercialize the conventional weather strip. 
     Furthermore, there is provided European Patent Application No. 01197519 that relates to a method for making a polyolefin resin compound having improved strength, impact resistance and heat resistance and to a polyolefin resin composition for making a polyolefin product. In this document, however, the problems the above-mentioned conventional practices have had are still found. 
     DISCLOSURE 
     Technical Problem 
     Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide an automobile weather strip and a method for manufacturing the same that applies a liquid-phase slip agent to the surface of a seal part or coupling member of the weather strip, thereby improving the emotional quality, reinforcement, and durability thereof. 
     Technical Solution 
     To accomplish the above-mentioned object, according to the present invention, there is provided a method for manufacturing an automobile weather strip having a seal part having a sectional shape of U and a sealing function, a coupling member formed unitarily with the seal part in such a manner as to be coupled to a flange portion of an automobile, and a seam material insertedly disposed inside the coupling member, the method including: (a) weather strip manufacturing step wherein the seam material and a thermoplastic elastomer are extruded and molded; (b) pretreatment step wherein the surface of the weather strip manufactured is pretreated; (c) slip agent applying step wherein a slip agent made by mixing silicone and polyurethane is applied to the surface of the weather strip pretreated through the pretreatment step; and (d) curing step wherein the slip agent coating layer formed through the slip agent applying step is cured. 
     According to the present invention, desirably, the pretreatment step (b) is carried out through any one of a primer applying method and an electrical plasma radiation method. 
     According to the present invention, desirably, at the slip agent applying step (c), the slip agent made by mixing the silicone and polyurethane is applied to the surface of the weather strip when the surface temperature of the weather strip is in a range of 25 to 150° C. 
     According to the present invention, desirably, the slip agent is made of any one selected from 20 to 90% by weight of silicone and 10 to 80% by weight of polyurethane or a combination of the two or more. 
     According to the present invention, desirably, at the curing step (d), the weather strip is cured through any one or combination of infrared (IR) light, near infrared (NIR) light, and heat at a given temperature of 50 to 160° C. for a given period of time. 
     According to the present invention, desirably, the method further includes: (e) first cooling step in which the weather strip becomes cool after the weather strip manufacturing step (a) or after the pretreatment step (b); and (f) second cooling step in which the weather strip becomes cool after the curing step (d). 
     According to the present invention, desirably, the seam material of the weather strip is made of any one of a thermoplastic material such as polypropylene or polyamide and steel, the thermoplastic material having talc or glass fiber added thereto. 
     According to the present invention, desirably, the thermoplastic elastomer includes any one selected from a thermoplastic styrenic block copolymer SBC, a thermoplastic olefinic elastomer TPO, thermoplastic polyurethane TPU, a thermoplastic polyamide TPAE, a thermoplastic polyester elastomer TPEE, thermoplastic polyvinyl chloride TPVC, and modified products thereof or a combination of the two or more. 
     Advantageous Effects 
     According to the present invention, the automobile weather strip and the method for manufacturing the same can improve emotional quality, compression set performance, reinforcement, and durability thereof. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view showing an automobile weather strip according to the present invention. 
         FIG. 2  is a flowchart showing a method for manufacturing an automobile weather strip according to the present invention. 
         FIGS. 3 and 4  are a table and graphs showing the test results of long term load loss set (LLS) of GMW 15564 of the weather strip manufactured according to the present invention. 
         FIG. 5  is a sectional view showing various examples of the weather strip manufactured according to the present invention. 
     
    
    
     BEST MODE FOR INVENTION 
     Objects, characteristics and advantages of the present invention will be more clearly understood from the detailed description as will be described below and the attached drawings. Before the present invention is disclosed and described, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to variously employ the present invention in virtually any appropriately detailed structure. In the description, it should be noted that the parts corresponding to those of the drawings are indicated by corresponding reference numerals. 
     Hereinafter, an explanation on a method for manufacturing an automobile weather strip according to the present invention will be in detail given with reference to the attached drawing. 
       FIG. 1  is a sectional view showing an automobile weather strip according to the present invention, and  FIG. 2  is a flowchart showing a method for manufacturing an automobile weather strip according to the present invention. 
     As shown in  FIGS. 1 and 2 , an automobile weather strip  10  according to the present invention includes a seal part  11  having a sectional shape of U and a sealing function, a coupling member  13  formed unitarily with the seal part  11  in such a manner as to be coupled to a flange portion of an automobile, and a seam material  12  insertedly disposed inside the coupling member  13 . 
     Further, a method for manufacturing an automobile weather strip according to the present invention includes a weather strip manufacturing step S 10 , a pretreatment step S 20 , a slip agent applying step S 30 , and a curing step S 40 . 
     At the weather strip manufacturing step S 10 , first, the seam material  12  and a thermoplastic elastomer are extruded and molded to make the weather strip  10 . 
     At this time, desirably, the seam material  12  of the weather strip  10  is made of any one selected from a thermoplastic material made by adding talc or glass fiber to polypropylene or polyamide and steel. 
     At the pretreatment step S 20 , pretreatments like chemical, electrical, and physical treatments are applied to the surface of the coupling member  13  and the surface of the seal part  11  of the weather strip  10  manufactured through the weather strip manufacturing step S 10 . 
     When the surface temperature of the weather strip  10  is in a range of 25 to 150° C., at this time, a primer is desirably applied and then cured within one minute. 
     At this time, the primer includes one or more selected from the group consisting of fluorine, polypropylene, polyethylene, carbon, amide wax, adhesion promoter and oil. 
     At the slip agent applying step S 30 , a slip agent including silicone and polyurethane mixed to each other is applied to the surface of the primer applied through the pretreatment step S 20 . 
     Under the slip agent applying step S 30 , at this time, the slip agent made by mixing silicone and polyurethane is desirably applied to the surface of the weather strip  10  when the surface temperature of the weather strip  10  is in a range of 25 to 150° C. 
     At this time, the slip agent is made by mixing 20 to 90% by weight of the silicone and 10 to 80% by weight of the polyurethane. 
     More desirably, the slip agent is applied to the surface of the weather strip  10  when the surface temperature of the weather strip  10  is in a range of 80 to 100° C. 
     That is, the application of the slip agent to the surface of the weather strip  10  improves emotional quality and compression set of the automobile. 
     Further, dust contamination caused by static electricity can be prevented. 
     At the curing step S 40 , a coating layer formed by the application of the primer and the slip agent is cured. 
     Under the curing step S 40 , at this time, the weather strip  10  is desirably cured through any one or combination of infrared (IR) light, near infrared (NIR) light, and heat at a room temperature or a temperature of 160° C. or under within five minutes. 
     Particularly, the weather strip  10  is effectively cured through indirect heat like infrared (IR) light, near infrared (NIR) light, and heat, thereby preventing the occurrence of the heat deflection of the weather strip  10 . 
     Further, the method for manufacturing the automobile weather strip according to the present invention includes a first cooling step and a second cooling step. 
     At the first cooling step, the weather strip  10  becomes cool after the weather strip manufacturing step or after the primer application step. 
     At the second cooling step, the weather strip  10  becomes cool after the curing step. 
     The manufactured weather strip  10  is made of a styrenic or olefinic rubber or elastomer. 
     At this time, the thermoplastic elastomer is desirably made of any one selected from a thermoplastic styrenic block copolymer SBC, a thermoplastic olefinic elastomer TPO, thermoplastic polyurethane TPU, a thermoplastic polyamide TPAE, a thermoplastic polyester elastomer TPEE, thermoplastic polyvinyl chloride TPVC, and modified products thereof or a combination of the two or more. 
     At this time, the material used for the seal part of the weather strip desirably has a tensile strength in a range of 1.0 to 5.0 Mpa. 
     Hereinafter, the test result of long term load loss set (LLS) of GMW 15564 of the weather strip manufactured according to the present invention will be explained. 
       FIGS. 3 and 4  are a table and graphs showing the test results of long term load loss set (LLS) of GMW 15564 of the weather strip manufactured according to the present invention. 
     Referring to the test result of long term load loss set (LLS) of GMW 15564 of the weather strip manufactured according to the present invention as shown in  FIGS. 3 and 4 , the standard of the weather strip  10  has to have the rate of change on compressive load of 43% or under at a temperature condition of 80° C. for 360 hours. 
     As shown in  FIGS. 3 and 4 , that is, the method for manufacturing the automobile weather strip according to the present invention is carried out wherein the slip agent made by mixing the silicone and polyurethane is applied to the surface of the thermoplastic elastomer, and in this case, the rate of change on compressive load at a temperature condition of 80° C. for 360 hours is 38.2%. On the other hand, it can be appreciated that other weather strips have the rate of change on compressive load of 43% or more. 
     The method for manufacturing the automobile weather strip according to the present invention is carried out wherein the weather strip is made of the thermoplastic elastomer and the slip agent made by mixing the silicone and polyurethane is applied to the surface of the thermoplastic elastomer, thereby satisfying the above-mentioned standard of the weather strip  10 . 
     As described above, the weather strip according to the present invention includes the seal part  11  having a sectional shape of U and a sealing function, the coupling member  13  formed unitarily with the seal part  11  in such a manner as to be coupled to a flange portion of an automobile, and the seam material  12  insertedly disposed inside the coupling member  13 , and the weather strip is made by extruding and molding the seam material  12  and a thermoplastic elastomer. Next, the primer is applied to the surface of the extruded weather strip  10 , and the slip agent made by mixing silicone and polyurethane is applied to the surface of the applied primer. After that, the primer and slip agent coating layer is cured, and in this case, the primer is applied and then cured within one minute when the surface temperature of the weather strip  10  is in a range of 25 to 150° C. Further, the slip agent made by mixing silicone and polyurethane is sprayed on the surface of the weather strip when the surface temperature of the weather strip  10  is in a range of 25 to 150° C. At this time, the slip agent is made by mixing 50 to 90% by weight of the silicone and 10 to 50% by weight of the polyurethane. 
     According to the present invention, further, the weather strip desirably has a tensile strength in a range of 2.0 to 3.0 Mpa. 
     According to the present invention, furthermore, the curing process of the coating layer is desirably carried out through any one or combination of infrared (IR) light, near infrared (NIR) light, and heat at a temperature of 50 to 160° C. or under within five minutes. 
     According to the present invention, moreover, the automobile weather strip according to the present invention includes the first cooling step wherein the weather strip  10  becomes cool after the primer is applied to the surface of the weather strip and the second cooling step wherein the weather strip  10  becomes cool after the slip agent coating layer is cured. 
     According to the present invention, further, the weather strip to which the slip agent is applied has a tensile modulus of 2000 to 5000 Mpa. 
       FIG. 5  is a sectional view showing various examples of the weather strip manufactured according to the present invention. 
     Referring to  FIG. 5 , the weather strip manufactured through the method for manufacturing the automobile weather strip according to the present invention is applicable to a variety of places such as a door side part, sunroof part, trunk and tail gate and so on, and provides more improvements in compression set performance, reinforcement, and durability than those in the conventional practices. 
     The foregoing description of the embodiments of the invention has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teachings. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. 
     EXPLANATION ON REFERENCE NUMERALS IN THE DRAWINGS 
       10 : weather strip 
       11 : seal part 
       12 : seam material 
       13 : coupling member