Grassland

Abstract

To provide a glass run which reduces the weight of the glass run and is excellent in productivity and durability.SOLUTION: A glass run includes an extrusion molding part formed by extrusion molding and a connection part connected to the extrusion molding part, in which the extrusion molding part includes a part formed of a resin composition A containing an ethylene-α-olefin copolymer subjected to silane crosslinking, and a part formed of a resin composition B containing a thermoplastic resin not subjected to silane crosslinking, the connection part includes a part formed of a resin composition C, in 50% tensile elongation under an atmosphere at 80°C, tensile stress of the connection part is comparable with, or lower than, tensile stress of the extrusion molding part, and tensile stress in 200% tensile elongation under an atmosphere at 80°C is 1.3 times or less tensile stress in the 50% tensile elongation.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a glass run. [Background technology]

[0002] Conventionally, research and development of glass runs of various structures and materials has been promoted in order to improve the sealing property, sound insulation property, etc. around the periphery of openings in the body of an automobile.

[0003] A glass run is a sealing material that forms a seal between the window frame and the window glass of an automobile door.

[0004] Furthermore, vulcanized rubber, which has excellent flexibility, has traditionally been used as the material for glass runs, but thermoplastic elastomers (TPEs) are being considered for reasons such as weight reduction, recyclability, and process simplification due to the lack of need for vulcanization. Depending on the purpose and application, glass runs can have a complex structure that combines straight sections with curved sections and corner sections, so in some cases, they are made into a composite material by joining components molded using different molding methods according to the shape.

[0005] Patent Document 1 describes a weather strip that uses a rubber composition containing ethylene-α-olefin copolymer rubber, α-olefin crystalline thermoplastic resin, α-olefin amorphous thermoplastic resin, and a softener as polymer components, thereby utilizing the excellent injection fusion properties to improve adhesion to molded parts made of vulcanized rubber, etc., and resulting in a weather strip with excellent strength as a composite. Furthermore, Patent Document 2 describes a technique in which a thermoplastic elastomer composition having high adhesive strength to vulcanized rubber and dynamically crosslinked thermoplastic elastomer (TPV) is used in the corners of a weather seal.

[0006] Furthermore, for the purpose of weight reduction, glass runs (glass run channels and belt moldings) using silane-crosslinked ethylene-α-olefin copolymer resins (hereinafter referred to as silane-based resins) are being developed. For example, in a conventional glass run, as shown in FIG. 10, a glass run 10 is attached to a frame 200 provided on a door 100 of a vehicle, and serves to guide a door glass 300 that moves up and down.

[0007] As shown in Figure 11, the glass run 10 has a groove portion M formed on the inside, and is equipped with a main body 11 consisting of an exterior side wall portion 12, an interior side wall portion 13, and a base wall portion 14 connecting them, an outer lip portion 15 protruding from the end side of the exterior side wall portion 12 toward the interior of the vehicle and in sliding contact with the door glass 300, and an inner lip portion 16 protruding from the end side of the interior side wall portion 13 toward the exterior of the vehicle and in sliding contact with the door glass 300.

[0008] In such glass runs 10, some products are molded using thermoplastic elastomers (TPE) for reasons such as weight reduction, recyclability, and process simplification due to the elimination of the need for vulcanization. However, since thermoplastic elastomer (TPE) has poor compression set compared to vulcanized rubber, the shape of the outer lip 15 and the inner lip 16 change over time, and the shape may become significantly warped from the initial state. As a result, the door glass 300 cannot be adequately held by both lips (the outer lip 15 and the inner lip 16), and as a result, the door glass 300 becomes more wobbly in the inside and outside of the vehicle, and when the door glass 300 is slightly open while driving, the door glass 300 vibrates in the vehicle width direction, causing a rattle noise.

[0009] Therefore, Patent Document 3 describes a glass run in which the exterior lip portion and the interior lip portion are formed from a silane-crosslinked ethylene-α-olefin copolymer, and the main body is formed from a thermoplastic resin that is not silane-crosslinked, which has excellent heat resistance and scratch resistance and can reduce the weight of the glass run. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2006-44077 A [Patent Document 2] JP 2016-113614 A [Patent Document 3] JP 2019-104387 A Summary of the Invention [Problem to be solved by the invention]

[0011] Glass runs using silane resins have high heat resistance and scratch resistance, making them durable and lightweight. However, when the extrusion molded part is made of silane resin, the tensile stress at high temperatures is higher than that of thermoplastic elastomers (TPEs) that have been used for extrusion molded parts up until now. Therefore, even if the material of the corner part (connection part) that is usually used is injection molded and heat fused to the extrusion molded part made of silane resin, the connection part may peel off if an object hits or gets caught on the connection part at high temperatures. This is because, although the extrusion molded part made of conventional thermoplastic elastomers is pulled and stretched and deformed at high temperatures, the stress on the connection interface is small because of the low tensile stress. However, when the extrusion molded part is made of silane resin, the flexibility at high temperatures is lower than that of conventional thermoplastic elastomers, so the stress on the connection interface is increased. In particular, in the process of injection molding the ends of extrusion molded parts to integrate the corners (connections), the connection interface is at a high temperature when the part is removed from the mold after injection molding, making it prone to peeling.

[0012] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a glass run which is lightweight and has excellent productivity and durability. [Means for solving the problem]

[0013] Therefore, the inventors conducted an investigation focusing on the tensile stress of the resin forming the connection part in a high-temperature atmosphere, and found that the above problem can be solved by making the tensile stress of the connection part at 50% tensile elongation in an 80°C atmosphere equal to or less than the tensile stress of the extrusion molded part of the part formed from the silane-based resin, and by making the tensile stress at 200% tensile elongation in an 80°C atmosphere 1.3 times or less the tensile stress at 50% tensile elongation. In other words, when silane resin is used as an extrusion molding material, its tensile stress at high temperatures is greater than that of conventionally used thermoplastic elastomers (TPEs), and while the tensile stress increases as the degree of elongation increases, not only does it reduce the tensile stress of the connection itself, but it also suppresses the increase in tensile stress even when the degree of elongation increases, so peeling does not occur at the connection interface. Therefore, in the process of integrally molding the connection part by subjecting the end of the extrusion molded part to injection molding (mold molding), when the integrated product including the connection part is removed from the mold after injection molding, there is no peeling at the connection interface. In this way, it has been found that the above problems can be solved. That is, in order to solve the above problems, the present invention has the following configuration.

[0014] [1] A glass run having an extrusion molded portion formed by extrusion molding and a connection portion connected to the extrusion molded portion, The extrusion molded part includes a portion formed of a resin composition A containing an ethylene-α-olefin copolymer subjected to silane crosslinking, and a portion formed of a resin composition B containing a thermoplastic resin not subjected to silane crosslinking, The connection portion includes a portion formed from resin composition C, and the tensile stress of the connection portion at 50% tensile elongation in an 80°C atmosphere is equal to or less than the tensile stress of the extrusion-molded portion, and the tensile stress at 200% tensile elongation in an 80°C atmosphere is 1.3 times or less than the tensile stress at 50% tensile elongation. [2] The glass run according to [1], wherein the tensile stress at the time of breaking of the connection portion is less than or equal to twice the tensile stress at the 50% tensile elongation. [3] The glass run according to [1] or [2], wherein the resin composition C contains a thermoplastic elastomer having a polyethylene resin content of 25 to 55 mass %. [4] The glass run according to [3], wherein the polyethylene resin is a linear low-density polyethylene. [5] a body portion that is attached along a frame provided on a vehicle door and guides a door glass that moves up and down into a groove, the body portion including an exterior side wall portion, an interior side wall portion, and a base wall portion that connects the exterior side wall portion and the interior side wall portion; a vehicle exterior lip portion that protrudes inward from the vehicle exterior side wall portion and is in sliding contact with the vehicle exterior surface of the door glass; an interior lip portion that protrudes inward from the interior side wall portion and is in sliding contact with an interior surface of the door glass; the vehicle exterior lip portion and the vehicle interior lip portion in the extrusion molded portion are portions formed from the resin composition A, The glass run according to any one of [1] to [4], wherein the main body portion in the extrusion molded part is a portion formed from the resin composition B. [6] The glass run according to [5], wherein the resin composition A forming the vehicle exterior lip portion and the vehicle interior lip portion does not contain an inorganic filler. Effect of the Invention

[0015] The glass run according to the embodiment of the present invention has the advantages of being lightweight, and being excellent in productivity and durability. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an external side view showing a glass run according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a schematic configuration of the periphery of a connection portion in a glass run according to an embodiment of the present invention. [Diagram 3] FIG. 11 is an enlarged cross-sectional view of the line AA in FIG. 10 showing the glass run according to the embodiment of the present invention. [Figure 4] 11 is an enlarged cross-sectional view taken along line AA in FIG. 10, illustrating a state in which the door glass is closed in the glass run illustrated in FIG. [Diagram 5] FIG. 4 is a block diagram showing a manufacturing line for the extrusion molding portion of the glass run shown in FIG. 3. [Figure 6] 6 is a cross-sectional view showing an extrusion-molded portion of a glass run extrusion-molded by the resin extruder shown in FIG. 5. [Figure 7] 6 is a cross-sectional view showing an extrusion-molded portion of another glass run according to an embodiment of the present invention, which is extrusion-molded by the resin extruder shown in FIG. 5. [Figure 8] 11 is an enlarged cross-sectional view taken along line AA in FIG. 10 , illustrating still another glass run according to the embodiment of the present invention, showing a state in which the door glass is closed. FIG. [Figure 9] 11 is an enlarged cross-sectional view taken along line AA in FIG. 10 , illustrating another glass run according to an embodiment of the present invention, showing a state in which the door glass is closed. FIG. [Figure 10] FIG. 2 is an external side view showing a door of a vehicle. [Figure 11] FIG. 11 is an enlarged cross-sectional view taken along line AA in FIG. 10, showing a glass run according to a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The glass run according to an embodiment of the present invention is a glass run having an extrusion molded portion formed by extrusion molding and a connection portion connected to the extrusion molded portion, The extrusion molded part includes a portion formed of a resin composition A containing an ethylene-α-olefin copolymer subjected to silane crosslinking, and a portion formed of a resin composition B containing a thermoplastic resin not subjected to silane crosslinking, The connection part includes a portion formed from resin composition C, and the tensile stress of the connection part at 50% tensile elongation in an 80°C atmosphere is equal to or less than the tensile stress of the extrusion-molded part, and the tensile stress at 200% tensile elongation in an 80°C atmosphere is 1.3 times or less than the tensile stress at 50% tensile elongation. Here, the tensile stress of the connection part being equal to or less than the tensile stress of the extrusion molded part means that the tensile stress of the connection part is 1.2 times or less, preferably 1.1 times or less, and further preferably 1.0 times or less, of the tensile stress of the extrusion molded part.

[0018] With reference to FIG. 1, a glass run according to an embodiment of the present invention will be described. A glass run according to an embodiment of the present invention includes an extrusion molded part formed by extrusion molding, and a connection part connected to the extrusion molded part. A glass run generally has a straight part and a curved part or a corner part, and the straight part or the curved part may be the extrusion molded part, and the curved part or the corner part may be the connection part formed by injection molding or the like. 1, the glass run 1 includes a first connection portion 2a connected to a first extrusion portion 1a, and a second connection portion 2b connected to a second extrusion portion 1b and a third extrusion portion 1c. The first extrusion portion 1a, the substantially L-shaped first connection portion 2a, the second extrusion portion 1b, the substantially L-shaped second connection portion 2b, and the third extrusion portion 1c are connected and integrated to form the glass run 1.

[0019] In the glass run 1, first, the first extrusion molding part 1a, the second extrusion molding part 1b, and the third extrusion molding part 1c are extrusion molded using a normal extruder or the like. Next, the ends of the first extrusion molding part 1a and the second extrusion molding part 1b are set in a mold, and the first connection part 2a is molded (injection molded) using an injection molding machine or the like. As a result, the first extrusion molding part 1a and the first connection part 2a, and the first connection part 2a and the second extrusion molding part 1b in the glass run 1 are molded integrally. Furthermore, the end of the second extrusion molding part 1b where the first connection part 2a is not formed, and the end of the third extrusion molding part 1c are set in a mold, and the second connection part 2b is molded (injection molded) using an injection molding machine or the like. As a result, the first extrusion molding part 1a, the first connection part 2a, the second extrusion molding part 1b, the second connection part 2b, and the third extrusion molding part 1c are integrated to form the glass run 1. The first connecting portion 2a and the second connecting portion 2b may be molded at the same time.

[0020] In the glass run according to the embodiment of the present invention, the extrusion-molded portion includes a portion formed of a resin composition A containing an ethylene-α-olefin copolymer crosslinked with silane and a portion formed of a resin composition B containing a thermoplastic resin not crosslinked with silane, and the connection portion includes a portion formed of a resin composition C, and the tensile stress of the connection portion at 50% tensile elongation in an 80°C atmosphere is equal to or less than the tensile stress of the extrusion-molded portion, and the tensile stress at 200% tensile elongation in an 80°C atmosphere is 1.3 times or less than the tensile stress at 50% tensile elongation. The tensile stress at 200% tensile elongation is preferably 1.2 times or less than the tensile stress at 50% tensile elongation. The tensile stress at the time of break at the tensile elongation of the connection portion is preferably 2 times or less, more preferably 1.5 times or less, of the tensile elongation of 50%. In addition, by forming the connecting part from resin composition C, compatibility with the resin forming the extrusion molded part is improved, improving the adhesive strength between the extrusion molded part and the connecting part, making it possible to produce a glass run with excellent durability. Furthermore, since the silane-crosslinked ethylene-α-olefin copolymer (hereinafter, silane material) continues to crosslink due to moisture in the air even after it is cooled after being molded by extrusion molding, it may develop unexpected curls depending on the storage conditions, and it is necessary to prevent curls from developing during storage or transportation in order to stabilize the shape of the product. However, the resin composition C that forms the connection part has flexible elasticity and prevents deformation of the extrusion molded part, so that it is possible to prevent curls from developing during storage or transportation of the glass run.

[0021] The resin compositions forming the extrusion molded parts and the connection parts will be described below. The resins constituting these resin compositions may be one type or a mixture (blend) of two or more types. They may also be foamed.

[0022] (Resin Composition A) Resin composition A contains a silane-crosslinked ethylene-α-olefin copolymer. The carbon number of the α-olefin constituting the ethylene-α-olefin copolymer is preferably 3 to 10. Examples of the olefin copolymerized with ethylene include α-olefins such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, and 1-decene. The ethylene-α-olefin copolymer preferably contains at least one selected from ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-octene copolymer. One of these may be used, or a mixture (blend) of two or more of these may be used. The resin composition A containing the silane-crosslinked ethylene-α-olefin copolymer may contain a styrene-butadiene copolymer resin (SBC), and in this case, the styrene-butadiene copolymer resin (SBC) containing process oil may be blended.

[0023] The resin composition A may or may not contain an inorganic filler. Examples of inorganic fillers include boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon black, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compounds, quartz, talc, zinc borate, white carbon, zinc borate, zinc hydroxystannate, and zinc stannate. Further, examples of inorganic fillers include metal hydrates such as compounds having water of hydration, hydroxyl groups, or water of crystallization. Examples of the metal hydrate include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and aluminum oxide hydrate; calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, and aluminum borate whiskers; and inorganic acid salts or inorganic oxides having water of hydration, such as hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, and hydrotalcite. In addition to the above, inorganic fillers also include various minerals and processed materials.

[0024] (Resin composition B) Resin composition B contains a thermoplastic resin that is not subjected to silane crosslinking. Examples of the thermoplastic resin in the thermoplastic resin not subjected to silane crosslinking include polyolefin resins such as polypropylene (PP) and polyethylene (PE), polyamide resins such as nylon 6 and nylon 6,6, polyester resins such as PVC (vinyl chloride resin), polyethylene terephthalate resin (PET) and polybutylene terephthalate resin (PBT), and thermoplastic elastomers, with thermoplastic elastomers (TPE) being preferred. The thermoplastic elastomer is not particularly limited, but examples thereof include olefin-based thermoplastic elastomers and styrene-based thermoplastic elastomers.

[0025] More specifically, it is preferable to use a thermoplastic elastomer (TPE) having three main components: polypropylene (PP) having excellent heat resistance, an amorphous polymer (rubber), and a filler. Examples of the amorphous polymer (rubber) include olefin-based rubber and styrene-based rubber, with EPM (ethylene propylene rubber) being preferred. Examples of the filler include talc and glass fiber, with talc being preferred.

[0026] The polyethylene-based resin used in resin composition B is not particularly limited, and examples thereof include low-density polyethylene-based resins, medium-density polyethylene-based resins, high-density polyethylene-based resins, linear low-density polyethylene-based resins, linear medium-density polyethylene-based resins, and linear high-density polyethylene-based resins, and these may be used alone or in combination.

[0027] (Resin composition C) The resin composition C forming the connecting portion preferably contains a polyethylene resin, and more preferably contains a thermoplastic elastomer with a polyethylene resin content of 25 to 55 mass %. The thermoplastic elastomer contained in the resin composition C may be the same as that contained in the resin composition B. The polyethylene resin is not particularly limited, and examples thereof include low-density polyethylene resin, medium-density polyethylene resin, high-density polyethylene resin, linear low-density polyethylene resin, linear medium-density polyethylene resin, linear high-density polyethylene resin, etc., which may be used alone or in combination. Among them, it is preferable to use a linear low-density polyethylene resin, and it is also preferable to contain an ethylene-α-olefin copolymer instead of or in addition to the linear low-density polyethylene resin. The carbon number of the α-olefin constituting the ethylene-α-olefin copolymer is preferably 3 to 10. Examples of the olefin copolymerized with ethylene include α-olefins such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, and 1-decene. The ethylene-α-olefin copolymer preferably contains at least one selected from an ethylene-butene copolymer, an ethylene-hexene copolymer, and an ethylene-octene copolymer. One of these may be used, or a mixture (blend) of two or more of these may be used.

[0028] By blending 25 to 55% by mass of a polyethylene resin, preferably a linear low-density polyethylene resin, in resin composition C, it is possible to reduce the tensile stress (modulus) at high temperatures without changing the hardness of the formed connection at room temperature, and to obtain higher flexibility at high temperatures than conventional glass runs. As a result, the connection can flexibly follow the deformation occurring around the connection due to the bending of the extrusion in a high-temperature atmosphere, and the connection state between the extrusion and the connection is easily maintained, making it possible to provide a glass run that is easy to handle and highly durable.

[0029] The content of the polyethylene resin in the resin composition C is 25 to 55% by mass, preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more, when the total amount of all the structural units constituting the resin composition C is 100% by mass, and is preferably 55% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less. If the content of the polyethylene resin in the resin composition C is less than 25% by mass, sufficient flexibility is not obtained. If the content of the polyethylene resin in the resin composition C is more than 55% by mass, the hardness required for a glass run is not obtained.

[0030] (Graslin) As shown in FIG. 10, a glass run 20 is attached to a frame 200 provided on a door 100 of a vehicle as a type of glass run, and serves to guide a door glass 300 that moves up and down.

[0031] The glass run according to an embodiment of the present invention is attached along a frame provided on a vehicle door and guides the rising and lowering door glass into a groove. The glass run includes a body portion including an exterior side wall portion, an interior side wall portion, and a base wall portion connecting the exterior side wall portion and the interior side wall portion; a vehicle exterior lip portion that protrudes inward from the vehicle exterior side wall portion and is in sliding contact with the vehicle exterior surface of the door glass; a glass run including an interior lip portion that protrudes inward from the interior side wall portion and is in sliding contact with an interior surface of the door glass, the vehicle exterior lip portion and the vehicle interior lip portion in the extrusion molded portion are portions formed from the resin composition A, In the extrusion-molded part, the main body portion is a portion formed from the resin composition B.

[0032] A glass run according to an embodiment of the present invention includes an extrusion molded portion formed by extrusion molding, and a connection portion connected to the extrusion molded portion. A glass run according to an embodiment of the present invention will be described with reference to Figs. Fig. 2 is a perspective view showing a schematic configuration of the periphery of a connection part in a glass run according to an embodiment of the present invention. In Fig. 2, the straight part of the glass run is an extrusion part, and the corner part is a connection part, and the first connection part 2a connects the first extrusion part 1a and the second extrusion part 1b. 10, the glass run according to the embodiment of the present invention is attached along a frame 200 provided on a door 100, and mainly comprises a main body 21 that guides the rising and lowering door glass 300 into a groove M, an outer lip 25, an inner lip 26, and a sub-lip 29. The glass run 20 extends upward from the inside of the door panel and is disposed so as to be continuous vertically across the belt line, and shown here as applied to the vertical side of the frame 200 on the front side of the vehicle body.

[0033] The extrusion molded portion includes a portion formed from resin composition A (hereinafter, sometimes referred to as silane material) containing ethylene-α-olefin copolymer that has been silane crosslinked, and thus has superior heat resistance and scratch resistance as well as the ability to reduce the weight of the glass run compared to conventional portions formed from vulcanized rubber or TPE that has not been silane crosslinked.

[0034] The hardness of the glass run is limited due to the smooth sliding performance with the door glass 300, and the same hardness is required for the part where the TPE is replaced with the silane material. However, the silane material in the extrusion molding part has lower flexibility at high temperatures compared to the one formed with the TPE without silane crosslinking of the same hardness.

[0035] In the extrusion molded part of the glass run in Figure 3, it was found that when each lip portion 25, 26, 29 is formed from a silane material, the tensile stress ((modulus)) is higher at high temperatures (80°C) than each lip portion 25, 26, 29 of an existing product molded entirely from TPE that has not been silane crosslinked. In other words, it was found that the silane material has a higher modulus at high temperatures than TPE that has not been silane crosslinked and has the same hardness at room temperature, and that the flexibility of the area around the joints of the extrusion molded parts is inferior at high temperatures. Here, the tensile stress is measured in accordance with JIS K6251.

[0036] In particular, when the connection part is injection molded and integrated with the extrusion molded part, and the integrated product is removed from the mold immediately afterwards, the connection part is in a high temperature state, and the pulling and twisting that occurs during removal may cause a tear in the connection interface (connection point) of the connection part.

[0037] In the glass run according to the embodiment of the present invention, the connecting portion is formed from the resin composition C containing a thermoplastic elastomer with a polyethylene resin content of 25 to 55% by mass, so that the tensile stress in a high temperature atmosphere can be easily reduced without changing the hardness, and the flexibility can be easily increased compared to the conventional glass run. As a result, when the integrated product is removed from the mold immediately after the connecting portion is injection molded and integrated with the extrusion molded portion, a cut is unlikely to occur at the connection interface of the connecting portion due to tension or twisting. In addition, the connecting portion can flexibly follow deformations that occur around the connecting portion during storage or transportation, or due to stress from the door glass or bending of each lip portion 25, 26, 29. Therefore, the connection state between the extrusion molded portion and the connection portion is maintained, making it possible to provide a glass run that is easy to handle and has high durability.

[0038] The materials constituting the connection parts and extrusion parts of the examples and comparative examples were evaluated for the following physical properties. The material of the connection part (connection member) was obtained as a sheet having a thickness of 2 mm in a mold using an injection molding machine, and then test pieces were taken. The material of the extrusion part (extrusion member) was obtained as a sheet having a thickness of 2 mm using an extruder, and then test pieces were taken. ·hardness In accordance with JIS K6253, the hardness was measured immediately after pressing the tester against the test piece and 15 seconds after pressing it against the test piece in an atmosphere of 23°C (normal temperature) using a type A durometer. The test piece was made of 2 mm thick sheets laminated together to a thickness of approximately 6 mm. Tensile properties In accordance with JIS K6251, the specimen was punched out into a dumbbell shape and the tensile stress was measured in an atmosphere of 23°C (normal temperature) and 80°C (high temperature). The tensile stress was measured when the distance between the marks on the specimen increased by 50%, 100%, and 200% (tensile elongation) and when the specimen was broken. The specimen was a No. 3 dumbbell.

[0039] For the connection members, the following conventional material and the material according to the invention (resin composition C) were used. Conventional material: Olefin-based thermoplastic elastomer -Material applied by the invention: 35 parts by mass of linear low-density polyethylene (LLDPE) added to conventional material

[0040] For the extrusion molding parts, the following conventional material and silane material (material according to the invention) were used. Conventional material: Olefin-based thermoplastic elastomer Silane material: Resin composition A containing ethylene-α-olefin copolymer crosslinked with silane

[0041] The results are shown in Table 1. Table 2 also shows the values ​​of each tensile stress, with the tensile stress at 50% tensile elongation taken as 100.

[0042] [Table 1]

[0043] [Table 2]

[0044] As can be seen from Tables 1 and 2, the hardness and tensile properties of the connecting members in an atmosphere of 23°C are the same for the conventional material and the material applied by the invention. However, at 50%, 100%, and 200% tensile elongation in an atmosphere of 80°C, the tensile stress is equal to or less than that of resin composition A, and when comparing the tensile stresses at 50% tensile elongation and 200% tensile elongation, the tensile stress at 200% tensile elongation is suppressed to 1.3 times or less than the tensile stress at 50% tensile elongation. And, since the tensile stress at break of the conventional material reaches about 2.3 times the tensile stress at 50% tensile elongation, there is little change in the material applied by the invention.

[0045] As shown in Table 3, the inventive examples in the present invention are combinations in which a silane crosslinking material is used as the extrusion molding member and an invention applicable material is used as the connection member. Table 3 shows the combined values ​​(added values) of the tensile stress of the connection member and the extrusion molding member shown in Table 1.

[0046] [Table 3]

[0047] Comparative Example 1 shown in Table 3 is a combination example in which a thermoplastic elastomer (both thermoplastic resins not crosslinked with silane) that has been used in products without problems in the past is used for the connection member and the extrusion molded member. In this Comparative Example 1, in the process in which the connection member is injection molded and integrated with the extrusion molded part, when the connection part is removed from the mold immediately after the integration (after molding with the mold), even if there is tension or twisting, no cuts are generated at the connection interface of the connection part. In contrast, in Comparative Example 2, when the connection part is removed from the mold after molding with the mold, if there is tension or twisting, a cut is generated at the connection interface of the connection part. This is thought to be because, as shown in Comparative Example 2 in Table 3, when a silane material is used for the extrusion molded part, the total value of tensile stress in an 80°C atmosphere is larger than that of Comparative Example 1.

[0048] In the invention example, when the connection part was removed from the mold after molding, no breaks occurred at the connection interface of the connection part even if it was pulled or twisted. This is presumably because, even though the extrusion molding member was a silane material, the connection member was made of the invention application material, so the tensile stress in a high temperature 80°C atmosphere was lower than that of the conventional material, and at 50% tensile elongation it was equal to or less than that of the extrusion molding member (1.1 times in Table 1). Moreover, when comparing 50% tensile elongation and 200% tensile elongation, the tensile stress at 200% tensile elongation was suppressed to 1.3 times or less than that at 50% tensile elongation (1.1 times in Table 1), and the tensile stress at break was also suppressed to 2 times or less than that at 50% tensile elongation (1.3 times in Table 1). The total tensile stress in an 80°C atmosphere was also about the same as Comparative Example 1, which had no conventional problems.

[0049] In addition, in terms of tensile stress in an 80°C atmosphere, in the combination of a connecting member and an extruded member made of conventional materials in Comparative Example 1, the extruded member had a smaller tensile stress than the connecting member, whereas in Comparative Example 2, in which the connecting member was made of a conventional material and the extruded member was made of a silane material, the tensile stress was close and the extruded member was larger than the connecting member at tensile elongation of 100% and 200%. Therefore, it can be seen that the combination of Comparative Example 2 has inferior flexibility. In addition, in the combination of the invention example, the tensile stress of the connection member of the invention application material is equal to or smaller than that of the silane material in an 80℃ atmosphere, and the connection member with excellent flexibility at high temperatures compensates for the silane material, which has poor flexibility at high temperatures. From this, it is believed that no cuts will occur at the connection interface of the connection part when it is removed from the mold after injection molding, even if it is pulled or twisted.

[0050] The extrusion molded portion of the glass run according to the present invention will be described in detail with reference to Figures 2 and 3. The main body 21 is made up of an exterior side wall 22, an interior side wall 23, and a base wall 24 connecting the exterior side wall 22 and the interior side wall 23, and has a generally U-shaped cross section with a groove M formed on the inside.

[0051] The outer lip portion 25 protrudes from the interior side of an outer support portion 31 that is integrally formed with the end portion of the exterior side wall portion 22 so as to extend obliquely toward the interior side of the vehicle and toward the base wall portion 24 side. In addition, opposite to the outer lip portion 25, the inner lip portion 26 protrudes from the outer surface of the inner support portion 32 which is integrally molded at the end of the inner side wall portion 23 so as to extend obliquely toward the outer side of the vehicle and toward the base wall portion 24. As shown in FIG. 4, the sub-lip portion 29 enters the inside of the inner lip portion 26 (on the vehicle interior side) and supports the tip of the inner lip portion 26 when the door glass 300 is closed.

[0052] In addition, a decorative lip portion 27 extending diagonally toward the outside of the vehicle is protruded from the outer side of the outer support portion 31, and a decorative lip portion 28 extending diagonally toward the inside of the vehicle is protruded from the inner side of the inner support portion 32. In addition, on the exterior side of the vehicle near the base wall portion 24 of the exterior side wall portion 22, and on the interior side of the vehicle near the base wall portion 24 of the interior side wall portion 23, locking protrusions 33, 34 are formed to lock the glass run 20 attached to the frame body 200 to the bent portion of the frame body 200 so that it does not easily come off from the frame body 200. The vehicle exterior side wall portion 22 and the base wall portion 24 are connected by a vehicle exterior connecting portion 38 having a thin wall thickness. The interior side wall portion 23 and the base wall portion 24 are also connected by a thin interior connecting portion 39. This makes it possible to assemble the vehicle by bending the cross-sectional shape at the time of extrusion (FIG. 6), which will be described later, into the assembled state shown in FIG. 3, etc., as designed.

[0053] The outer lip portion 25, inner lip portion 26, and sub-lip portion 29, which constitute the glass run 20, are formed from resin composition A containing an ethylene-α-olefin copolymer that has been subjected to silane crosslinking, and the main body portion 21 is formed from resin composition B containing a thermoplastic resin that has not been subjected to silane crosslinking. More specifically, the outer lip portion 25, the outer support portion 31 supporting the outer lip portion 25, the decorative lip portion 27 protruding therefrom, the inner lip portion 26, the inner support portion 32 supporting the inner lip portion 26, the decorative lip portion 28 protruding therefrom, and the sub-lip portion 29 are formed from resin composition A containing an ethylene-alpha olefin copolymer that has been subjected to silane crosslinking, and the other portions of the glass run 20 are formed from a thermoplastic resin that has not been subjected to silane crosslinking.

[0054] Moreover, the outer lip portion 25, the inner lip portion 26 and the sub-lip portion 29 in this embodiment are formed from the resin composition A containing the silane-crosslinked ethylene-α-olefin copolymer without blending an inorganic filler. Examples of the inorganic filler include those mentioned above.

[0055] In addition, in the glass run 20, the portions other than the portion formed with the resin composition A containing the silane-crosslinked ethylene-α-olefin copolymer, i.e., the main body portion 21 including the engaging protrusions 33, 34, are formed from a resin composition B containing a thermoplastic resin that is not silane-crosslinked, such as a thermoplastic elastomer (TPE), polypropylene (PP), polyethylene (PE), etc., or a mixture thereof. In this embodiment, an olefin-based thermoplastic elastomer (TPO) is used.

[0056] The extrusion molded portions (first extrusion molded portion 1a, second extrusion molded portion 1b, and third extrusion molded portion 1c) of the glass run 20 are manufactured in a production line as shown in FIG. That is, the resin is extruded in a desired integrated state at an appropriate temperature by the die of the resin extruder 501. The cross-sectional shape at this time is as shown in Fig. 6, and the sub-lip portion 29 is extruded downward and the lip portions 25, 26, and 29 are not in contact with each other. Thereafter, the extruded glass run 20 is immersed in a water tank 502 (cooling tank) and cooled. At this time, the glass run 20 is pulled by a puller 503 arranged behind the water tank 502, so that the glass run 20 is extruded in a continuous manner. The silane crosslinking applied to the lips 25, 26, 29 progresses due to the water in the water tank 502 and moisture in the air, so at least the crosslinking degree of the surface progresses and the scratch resistance of the surface is good. Therefore, it is a suitable material for the outer support part 31 and the decorative lip part 27 protruding therefrom, and the inner support part 32 and the decorative lip part 28 protruding therefrom.

[0057] According to such a glass run 20, the outer lip portion 25 which is the lip portion on the outside of the vehicle, the inner lip portion 26 which is the lip portion on the inside of the vehicle, and the sub-lip portion 29 are formed of the resin composition A containing an ethylene-α-olefin copolymer subjected to silane crosslinking, so that the glass run 20 having a lip portion with small compression set and high heat resistance and scratch resistance can be formed by a general thermoplastic resin extrusion molding facility that does not require a vulcanization facility using a high-temperature furnace. Therefore, even in a high-temperature environment, the rattle of the door glass 300 in the inside and outside of the vehicle does not increase, and the shape of the outer lip portion 25 and the inner lip portion 26 which support the door glass 300 does not change significantly over time. Even if the door glass 300 is driven with the door glass 300 slightly open, the door glass 300 does not vibrate in the vehicle width direction, and a problem such as a rattle sound is unlikely to occur.

[0058] In addition, since the main body 21 of the glass run 20 is formed using the resin composition B containing a thermoplastic resin that is not silane crosslinked, the straightness of the main body 21 can be maintained when storing until the next process after extrusion molding and cooling, or when transporting to an assembly site where a vehicle is installed. In other words, if silane crosslinking is performed up to the main body 21, there is a concern that unintended deformation of the shape may occur during storage, but this does not occur. This is because silane crosslinking is thought to progress due to moisture in the air even after molding, and therefore, for the main body 21 of the glass run 20, which requires smoothness corresponding to a smooth vehicle body, it is thought to be advantageous not to perform silane crosslinking, which is a concern for the occurrence of deformation. Furthermore, the shape of the main body 21, which takes into consideration assembly to the vehicle body, requires precise and complex thickness adjustment according to design instructions, such as the vehicle exterior connecting part 38 and the vehicle interior connecting part 39, and therefore requires high reshapeability in extrusion molding. However, if resin composition B containing a normal thermoplastic resin (e.g., TPE, PP, PE) that is not silane crosslinked is used, it can be easily molded with high reshapeability.

[0059] In addition, when forming each lip portion 25, 26, 29, since no inorganic filler is mixed into the resin composition A containing the silane-crosslinked ethylene-α-olefin copolymer, the specific gravity of the lip portions 25, 26, 29 can be made 0.9 or less, and the weight of the glass run 20 does not become particularly heavy.

[0060] Furthermore, since no inorganic filler is blended, the strength and rigidity of the lip portions 25, 26, 29 are inferior; however, by using an ethylene-α-olefin copolymer, particularly an ethylene-butene copolymer, an ethylene-hexene copolymer, an ethylene-octene copolymer, or a mixture thereof, good strength can be achieved by silane crosslinking. In this embodiment, an ethylene-octene copolymer was used as the ethylene-α-olefin copolymer, and this was blended with a styrene-butadiene copolymer resin (SBC) containing process oil. When measured using a JIS K6253 Type A durometer, a material with a durometer value in the range of 60 to 80 was obtained.

[0061] In addition, because styrene-butadiene copolymer resin (SBC) is blended into resin composition A containing silane-crosslinked ethylene-α-olefin copolymer, the moldability during extrusion is improved, making it easier to extrude the lip portions 25, 26, 29 into the desired shapes. This means that, while it is difficult to adjust the moldability by directly adding oil to the ethylene-α-olefin copolymer, the use of styrene-butadiene copolymer resin (SBC), which allows the addition of a large amount of oil, improves the moldability of the entire resin composition.

[0062] In this embodiment, the outer lip portion 25, the outer support portion 31 supporting the outer lip portion 25, the decorative lip portion 27 protruding therefrom, the inner lip portion 26, the inner support portion 32 supporting the inner lip portion 26, the decorative lip portion 28 protruding therefrom, and the sub-lip portion 29 are formed from resin composition A containing an ethylene-alpha olefin copolymer that has been subjected to silane crosslinking, and the other portions are formed from resin composition B that has not been subjected to silane crosslinking, but various embodiments can be considered without being limited to this. For example, the sub-lip portion 29 in FIG. 3 may be omitted.

[0063] Furthermore, the vehicle exterior lip portion and vehicle interior lip portion added to the glass run 20 can also be formed from the resin composition A containing the silane-crosslinked ethylene-α-olefin copolymer. For example, as shown in Figure 8, the exterior side sub-lip portion 35, which is located closer to the base wall portion 24 than the outer lip portion 25 in the exterior side wall portion 22, and the interior side sub-lip portion 36, which is located closer to the base wall portion 24 than the inner lip portion 26 in the interior side wall portion 23, can also be formed from a resin composition A containing an ethylene-alpha olefin copolymer that has been subjected to silane cross-linking. Also, as shown in FIG. 9, a seal lip portion 37 that elastically contacts the end of the door glass 300 from the inside of the vehicle can be protruded inside the base wall portion 24, and this seal lip portion 37 can also be formed from a resin composition A containing an ethylene-α-olefin copolymer that has been silane-crosslinked.

[0064] Also, for example, as shown in Figure 3, the outer lip portion 25, the inner lip portion 26, and the sub-lip portion 29 can be formed from a resin composition A containing an ethylene-alpha olefin copolymer that has been silane crosslinked, and other portions such as the outer support portion 31 and the decorative lip portion 27 protruding therefrom, and the inner support portion 32 and the decorative lip portion 28 protruding therefrom can be formed from a resin composition B. In addition, a portion of the outer lip portion 25, the inner lip portion 26, and the sub-lip portion 29 can be formed from resin composition A containing a silane-crosslinked ethylene-α-olefin copolymer, and the other portions can be formed from resin composition B and a conventionally used TPE.

[0065] Next, the ends of the first extrusion 1a and the second extrusion 1b are set in a mold, and the first connection 2a is molded as a corner portion using an injection molding machine or the like. As a result, the first extrusion 1a, the first connection 2a, and the second extrusion 1b in the glass run are molded integrally. Furthermore, the end of the second extrusion 1b where the first connection 2a is not formed, and the third extrusion 1c are set in a mold, and the second connection 2b is molded using an injection molding machine or the like. As a result, the first extrusion 1a, the first connection 2a, the second extrusion 1b, the second connection 2b, and the third extrusion 1c are integrated to form a glass run.

[0066] The above-described embodiment is merely illustrative in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Explanation of symbols]

[0067] 1 Grassland 1a First extrusion molding section 1b Second extrusion molding section 1c Third extrusion molding section 2a First connection part 2b Second connection part 10 Grassland 11 Main body 12 Vehicle exterior side wall 13 Car interior side wall 14 Basal wall 15 Outer lip 15a Outer layer 15b Inner layer 16 Inner lip 16a Outer layer 16b Inner layer 20 Grassland 21 Main body 22 Vehicle exterior side wall 23 Car interior side wall 24 Basal wall 25 Outer lip (car exterior lip) 26 Inner lip (car interior lip) 27 Design lip 28 Design lip 29 Sub-lip section 31 Outer support part 32 Inner support part 33 Locking protrusion 34 Locking protrusion 35 Sub-lip part on the outside of the car 36 Inner side sub-lip 37 Seal lip 38 External connection part 39 Inner side connection 100 Doors 200 frame 300 Door Glass 501 Resin Extruder 502 Aquarium 503 Collection Machine M Groove

Claims

1. A glass run having an extrusion molded portion formed by extrusion molding and a connection portion connected to the extrusion molded portion, The extrusion molded part includes a portion formed of a resin composition A containing an ethylene-α-olefin copolymer subjected to silane crosslinking, and a portion formed of a resin composition B containing a thermoplastic resin not subjected to silane crosslinking, The connection portion includes a portion formed from resin composition C, and resin composition C includes a thermoplastic elastomer having a polyethylene resin content of 25 to 55 mass %, and the tensile stress of the connection portion at a 50% tensile elongation in an 80°C atmosphere is equal to or less than the tensile stress of the extrusion-molded portion, and the tensile stress at a 200% tensile elongation in an 80°C atmosphere is 1.3 times or less than the 50% tensile elongation.

2. The glass run according to claim 1 , wherein the tensile stress at the time of breaking of the connection portion is equal to or less than twice the tensile stress at the 50% tensile elongation.

3. 3. The glass run according to claim 1, wherein the polyethylene resin is a linear low-density polyethylene.

4. a body portion that is attached along a frame provided on a vehicle door and guides a door glass that moves up and down into a groove, the body portion including an exterior side wall portion, an interior side wall portion, and a base wall portion that connects the exterior side wall portion and the interior side wall portion; a vehicle exterior lip portion that protrudes inward from the vehicle exterior side wall portion and is in sliding contact with the vehicle exterior surface of the door glass; an interior lip portion that protrudes inward from the interior side wall portion and is in sliding contact with an interior surface of the door glass; the vehicle exterior lip portion and the vehicle interior lip portion in the extrusion molded portion are portions formed from the resin composition A, The glass run according to any one of claims 1 to 3, wherein the main body portion in the extrusion molded portion is a portion formed from the resin composition B.

5. The glass run according to claim 4 , wherein the resin composition A forming the vehicle exterior lip portion and the vehicle interior lip portion does not contain an inorganic filler.

Images