JP3964363B2 - Automotive seals - Google Patents

Description

The present invention relates to an automotive seal member represented by, for example, a weather strip, and more particularly to an automotive seal member considering reduction of corrosion of an aluminum alloy generated at a contact portion with an aluminum alloy panel or the like.

  As is well known, ethylene-propylene-nonconjugated diene copolymer rubber is particularly excellent in weather resistance, and is therefore widely used as a material for automotive sealing materials such as weather strips.

  On the other hand, in recent years, aluminum alloys with a lower density ratio compared to steel plate materials for panels such as bodies, doors, and hoods (bonnets) have been developed from the viewpoint of reducing the weight, performance and fuel consumption of automobile bodies. There is a tendency to increase the number of examples made of materials.

  When such an aluminum alloy panel is used, the corrosion of the aluminum alloy itself has emerged as a new problem, particularly due to the presence of the electrolyte solution at the contact portion between the rubber material containing carbon black and the aluminum alloy. Since it is known that corrosion of an aluminum alloy is progressing (generally, the local battery theory in the electric corrosion of aluminum alloys is prominent), for example, the technique described in Patent Document 1 has been proposed as a countermeasure. Yes.

In the technique described in Patent Document 1, when the surface electrical resistance value of a rubber member such as a weather strip containing carbon black is 10 ⁶ (Ω) or more, aluminum that comes into contact with the rubber member is obtained. It is said that corrosion of the alloy can be suppressed.
Japanese Patent No. 2610165

However, in order to make the surface electrical resistance value of the rubber member 10 ⁶ (Ω) or more, it is most effective to control the blending ratio of carbon black in the total rubber blending amount. In addition to the rise, the extrudability of rubber parts such as weather strips that are based on extrusion deteriorates, and in particular, the extruding skin deteriorates, the discharge discharge varies, and the product shrinks after extrusion. This is not preferable because the productivity is lowered.

The present invention has been made by paying attention to such problems, and in particular, it has improved the electrolytic corrosion resistance of an aluminum alloy without being particular about the surface electrical resistance value of a rubber member, and at the same time, an automotive seal excellent in workability. The member is to be provided.

  That is, even if the electric resistance value of the rubber composition containing carbon black is relatively low, corrosion of the aluminum alloy at the contact portion with the aluminum alloy is to be suppressed.

  The present invention is an Arrhenius equation (Andrade equation) that represents the temperature dependence of a viscoelastic material using the complex viscosity and the value of the complex elastic modulus obtained by the viscoelasticity measurement (1) The apparent activation energy Ea is calculated based on the equation, and the change rate G * r (abbreviation of G * rate) of the complex elastic modulus representing the shear rate dependence of the viscoelastic property is calculated. It is based on the prediction of the correlation between the kneading state of the base rubber and the corrosivity and workability of the aluminum alloy.

η * = Aexp (Ea / RT) (1)
However,
η * is the complex viscosity Ea is the abbreviation of Activation Energy, and the apparent activation energy of flow (compound viscosity) (× 10 ⁻¹ KJ / mol)
T is temperature R is gas constant

That is, the present invention is an automotive seal member that is mounted on a part of the body of an automobile and whose surface is in contact with the counterpart member made of an aluminum alloy, and the following conditions (a) to (c) It is formed with the rubber composition which satisfy | fills.
(A) SRF type carbon black is blended in 110 to 190 phr in 100 phr of ethylene-α-olefin-nonconjugated diene copolymer rubber .
(A) The surface electrical resistance value when crosslinked by extrusion molding vulcanization is 10 ⁴ (Ω) or more and less than 10 ⁶ (Ω) .
(C) viscoelastic properties of the unvulcanized rubber composition was Cphr blending carbon black below (a), and this satisfies the (b).

(A) The apparent activation energy Ea (× 10 ⁻¹ KJ / mol) of the complex viscosity is 50 ≦ Ea ≦ 230 .

(B) The rate of change G * r of the complex elastic modulus is 0.9 × (100−0.36C) ≦ G * r (%) (2)
Be.

  Carbon black compounded rubber can form a rubber molecular layer constrained around the carbon black while being physically or chemically adsorbed or desorbed as the carbon / polymer interaction is activated with kneading. Are known.

  The apparent activation energy Ea described above is a scale for evaluating the structure of the constrained rubber molecular layer around the carbon black that changes with the kneading time.

  This indicates that when the apparent activation energy Ea increases with the kneading time, the mobility of the constrained rubber molecular layer around the carbon black increases, and conversely the apparent activation energy. It can be easily understood from the fact that it has been verified that when the value of Ea decreases with the kneading time, the mobility of the constrained rubber molecular layer around the carbon black is reduced.

  From this, the change in the mobility of the rubber molecular layer around the carbon black, which is the internal structure of the kneaded rubber, is the extrudability during extrusion, that is, the surface skin of the extruded product (appearance looks) and the extrusion discharge amount. It was estimated that it would greatly affect the variation of

  As for the surface skin (appearance appearance) of the extruded product, as described above, the apparent activation energy Ea is a measure of the structural change of the restrained rubber molecular weight around the carbon black. The mobility of rubber molecules around the carbon black is lowered, and so-called gelation occurs. As a result, crushing convex portions appear on the surface of the extrusion-molded product, and the appearance looks worse.

  As for the variation in the extrusion discharge amount, when the apparent activation energy Ea is too high, the mobility of the rubber molecules around the carbon black increases, so that the fluidity tends to be inhomogeneous. Variations in quantity occur.

  Furthermore, during the extrusion process in the extrusion process, the material is transported by the screw in the process of moving sequentially from feed zone → cylinder → extrusion head → mouthpiece, so various temperature histories in the process from material charging to discharging. Receive.

  A material that is easily affected by the viscosity of rubber due to a temperature change (a material having a large apparent activation energy Ea) is likely to change in fluidity, and therefore, the extrusion fluidity is likely to vary due to slight environmental changes during extrusion. For example, in a mass production extruder having a diameter of 70 or more, the length variation in the discharge direction tends to be larger than the swell change in the cross section due to the value of Ea.

  From these facts, it was found that by evaluating the apparent activation energy Ea of the compounded rubber material, it is possible to evaluate the surface skin and the extrusion discharge amount variation of the extruded product of the carbon black compounded rubber.

  On the other hand, in a rubber kneaded state, the rate of change G * r of the complex elastic modulus is an index expressing viscoelastic characteristics well known as the Payne effect. Since the rate of change G * r of the complex elastic modulus in the same rubber compounding has a correlation with the electric resistance value of the unvulcanized rubber composition, it is considered to indicate the microdispersibility (by microscopic observation) of carbon black.

  From these facts, the present inventors determined that the kneading state of the carbon black compounded rubber can be evaluated from the apparent activation energy Ea and the complex elastic modulus change rate G * r.

  Further, in such a carbon black compounded rubber composition, it is presumed that the quality of the kneading process greatly affects the quality of the rubber, so that the rubber composition obtained by crosslinking the carbon black compounded rubber In order to ensure the aluminum electrolytic corrosion resistance, it is important to secure the optimum complex elastic modulus change rate G * r that varies with the amount of carbon black, which can be defined by the above equation (2). found.

  More specifically, as described above, in the carbon black compounded rubber composition, the quality of the kneading process greatly affects the quality of the extruded product after extrusion molding. The present inventors have grasped in detail the interaction between rubber and carbon black from both the apparent activation energy Ea of the complex viscosity obtained by viscoelasticity measurement and the rate of change G * r of the complex elastic modulus. Based on the knowledge that it is possible, the correlation with the aluminum electrolytic corrosion resistance of the rubber composition obtained by crosslinking was examined.

In the crosslinked rubber composition having a surface electrical resistance value of 10 ⁴ (Ω) or more and less than 10 ⁶ (Ω) , the degree of quality of the kneading process is considered to be a cause of changing the aluminum corrosion resistance.

By evaluating the unvulcanized carbon black compound rubber composition with this viscoelastic index, even if the surface electrical resistance value is in the range of 10 ⁴ (Ω) to less than 10 ⁶ (Ω) , the complex viscosity When the rubber kneaded state positioned from the apparent activation energy Ea of the modulus and the rate of change G * r of the complex elastic modulus satisfies the conditions (a) and (b) of claim 1, the aluminum alloy is not corroded over a long period of time. Moreover, it has been found that a rubber composition having good extrudability can be obtained.

  That is, when the rate of change G * r of the complex elastic modulus is equal to or greater than 0.9 × (100−0.36C), no electrical corrosion occurs on the aluminum alloy due to contact with the aluminum alloy. When the change rate G * r of the complex elastic modulus is smaller than 0.9 × (100−0.36C), electric corrosion occurs in the aluminum alloy due to contact with the aluminum alloy.

In addition, when the apparent activation energy Ea of the complex viscosity satisfies 50 ≦ Ea ≦ 230 , there is little variation in the discharge amount when the automotive seal member such as a weather strip is extruded, and the product after the extrusion There is also a tendency for shrinkage to decrease. On the other hand, when the value of Ea is Ea <50, a so-called rough skin occurs on the surface of the extruded product, resulting in poor appearance. In addition, when the value of Ea is Ea> 230 , the discharge amount variation at the time of extrusion molding becomes significantly worse, so that the productivity is lowered. Moreover, the shrinkage of the extruded product is increased, leading to a decrease in dimensional accuracy.

On the other hand, when attention is paid to the surface electrical resistance value of the extruded product, if the value falls below 10 ⁴ (Ω), the aluminum corrosion resistance deteriorates, and the value is 10 ⁶ (Ω) or more. However, if the rate of change G * r of the complex elastic modulus does not satisfy the above formula (2), electrolytic corrosion occurs in the aluminum alloy.

According to the present invention , the aluminum electrolytic corrosion resistance is excellent and the extrusion processability is also excellent, and there is an effect that both the aluminum corrosion resistance and the extrusion processability can be achieved.

  About several sample No1-No15 (total of Examples 1-7 and Comparative Examples 1-8) of the rubber composition from which kneading | mixing conditions differ although it is the same mixing | blending, unvulcanized characteristic, extrusion processability, and vulcanized rubber characteristic The results of the evaluation are shown in Tables 1-3.

  Samples No. 1 to No. 15 in Tables 1 to 3 have a common EPDM (ethylene-propylene-5-ethylidene-2-norbornene) of 100 phr, which is an ethylene-α-olefin-nonconjugated diene copolymer rubber, and carbon. A total of five types were prepared by blending black (SRF) in a range of 110 to 190 phr and paraffinic oil, which is also a softening agent, in a range of 50 to 70 phr, stepwise.

  Examples of the α-olefin of the ethylene-α-olefin-nonconjugated diene copolymer rubber include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-hexene, Examples include 1-decene, and propylene is preferable. Of course, a plurality of the α-olefin groups may be selected and used in combination such as propylene and 1-butene.

  Examples of non-conjugated dienes include 1.4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene and the like.

  Examples of the carbon black include HAF, FEF, MAF, SRF and the like, and preferably an SRF type having a large particle diameter.

  In addition, in addition to carbon black and paraffinic oil, the following are commonly added to each sample No1 to No15.

(1) Additives Zinc oxide 3 phr
Stearic acid 1phr
Polyethylene glycol 1phr
(2) Inorganic filler clay (fired clay) 20 phr
(3) Vulcanization accelerator 5 phr
(4) Vulcanizing agent (sulfur) 1 phr
Here, the additive amount of zinc oxide as an additive is at most about 5 phr, similarly the amount of stearic acid is at most about 3 phr, and if any of them is too small, the vulcanization progresses slowly. When the amount is too large, bloom (whitening phenomenon) tends to occur.

  In addition to clay, for example, talc, silica, calcium carbonate, calcium silicate, magnesium carbonate, magnesium hydroxide, aluminum oxide, zeolite and the like can be used as the inorganic filler. However, any one of the above-mentioned calcined clay, silica, and talc is preferable. The blending amount of the inorganic filler typified by calcined clay is about 30 phr at most, and if it exceeds this, the kneadability and the sag resistance of the product deteriorate, which is not preferable.

Vulcanization accelerators, such as thiazole, thiuram, sulfenamide, guanidine, thiourea, dithiocarbamate, etc., commonly used for rubber compounding are mixed and used. can do. Preferably, thiazole type, thiuram type, and sulfenamide type are mixed and used. The amount of the vulcanization accelerator is about 2 to 8 phr (5 phr in the above example). Similarly to the case of the additive, if the amount is too small, the progress of vulcanization becomes slow, and if the amount is too large, the blooming is performed. Is likely to occur. Particularly those of the dithiocarbamate is a vulcanization accelerator metal salt, require attention from the occurrence of the bloom causes material tends to galvanic corrosion of the aluminum alloy.

  The amount of sulfur as a vulcanizing agent is about 0.5 to 2 phr (1 phr in the above example). If the amount is too small, the progress of vulcanization is slow, and if the amount is too large, bloom occurs. It becomes easy.

  In addition to sulfur-based crosslinking, organic peroxide-based crosslinking or a combination of both can be used as the crosslinking mode.

  Of course, other than the above, for example, an antioxidant, a heat stabilizer, an ultraviolet absorber, a light stabilizer, a flame retardant, an organic or inorganic pigment, a recycled rubber, a foaming agent, etc. can be appropriately blended as necessary. It is.

In addition, even when a foaming agent or the like is mixed and used as sponge rubber, the surface electrical resistance value apparently increases because of the foamed cell portion. However, in the crosslinked rubber component, care must be taken because electric corrosion is likely to occur unless it satisfies the first aspect .

  The kneading method for each sample No. 1 to No. 15 includes four types of blends in which the above-mentioned additives (1) and (2) and inorganic fillers are added to the above-mentioned EPDM, carbon black, and paraffinic oil as a softening agent. The materials were put into a tangential mixer and then kneaded under the three conditions A, B and C as shown in Table 4.

  After that, the mixture containing the vulcanization accelerator and the vulcanizing agent (sulfur), which are the blended materials of (3) and (4) described above, was extruded using a roll, and subjected to continuous vulcanization to obtain FIG. A vulcanized rubber sample having the cross-sectional shape shown in FIG.

  Tables 1 to 3 show the results of evaluation of unvulcanized characteristics (evaluation of uncrosslinked rubber composition), evaluation of extrusion processability, and evaluation of physical properties of crosslinked rubber as evaluation items. In particular, in the column of unvulcanized characteristic evaluation, as the viscoelastic characteristics of the uncrosslinked rubber composition, the value of the apparent activation energy Ea, the value of the change rate G * r of the complex elastic modulus, and (2 ) Appropriate values of G * r that can satisfy the equation are shown.

  Calculation of the value of the apparent activation energy Ea in Tables 1 to 3 was performed under the following conditions using “RPA2000 manufactured by Alpha Technologies” as a viscoelasticity measuring machine.

Measurement conditions Temperature: 60 ° C-80 ° C-100 ° C
Shear rate: 0.5 1 / s
Calculation method: Arrhenius type (Andrade's formula)
η * = Aexp (Ea / RT) (1)
However, as described above, η *: viscosity Ea: apparent activation energy of flow T: temperature R: gas constant

  From the above measurement conditions, a complex viscosity η * of 60 ° C.-80 ° C.-100 ° C. was calculated and plotted in the previous equation (1) to calculate Ea.

  Further, the rate of change G * r, which is the shear rate dependence of the complex elastic modulus, was calculated under the following conditions using “RPA2000 made by Alpha Technologies” as a viscoelasticity measuring machine.

Measurement conditions Temperature: 80 ℃
Shear rate: (a) 10.0 1 / s
(B) 19.8 1 / s
Then, the complex elastic modulus G * at the shear rate (a) and (b) was plotted in the following equation (3) to calculate the rate of change G * r.

G * r (%) = {G *} of (b) / {G *} of (a) × 100 (3)
The extrudability evaluation items in Tables 1 to 3 include the surface appearance of the extrusion-molded product and the discharge amount variation during extrusion.

  The surface appearance of the extrusion-molded product was recorded by visually observing each of the vulcanized extrusion-molded products extruded under the blending of the samples No. 1 to No. 15 and recording the results. On the other hand, the discharge amount variation at the time of extrusion is extrusion molding of the cross-sectional shape of FIG. 1 under the formulation of each sample No. 1 to No. 15 on the assumption that extrusion is performed from a φ75 mm extruder at a screw rotation speed of 20 rpm. After recording the discharge weight (n: 100) for 1 minute when the product S1 was extrusion molded, the weight variation was determined as the discharge amount variation rate (%) by the following equation (4). The target value was 3% or less.

Discharge rate variation rate (%) = {(maximum discharge amount (g) −minimum discharge amount (g)) / average discharge amount (g)} × 100 (4)
In addition, the evaluation items for the properties of the crosslinked rubber in Tables 1 to 3 include the evaluation items for the surface electrical resistance (Ω), the aluminum electrolytic corrosion property, and the shrinkage property.

  The measurement of the surface electrical resistance value (Ω) is shown in FIG. 2 from the vulcanized extruded product S1 (with the cross-sectional shape in FIG. 1) that is extruded under the blending of the samples No. 1 to No. 15 in Tables 1 to 3. A sample S2 having a shape as shown below was cut out. As shown in the drawing, the size of the sample S2 was set to a thickness t = 3 mm, a length W = 30 mm, and a width D = 5 mm. Then, brass electrodes are overlapped on both ends of the sample S2, and as shown in the figure, both ends in the longitudinal direction of the sample S2, that is, a range 1/3 of the whole (the hatched portion in FIG. 2) P are respectively provided. Adhere to the electrode. A surface electrical resistance value (Ω) was measured under an environment of 22 ° C. × 55% RH by applying a load of 500 g to the contact portion P between the sample S2 and the electrode. As a measuring instrument, “Loresta AP manufactured by Dia Instruments Co., Ltd.” was used.

  Here, the reason why the surface electric resistance value is used instead of the volume specific resistance value is as follows. That is, weather strips for automobiles made of EPDM or the like are often used by being fitted into a counterpart panel made of aluminum alloy, so that the aluminum alloy and the rubber that is the material of the weather strip are extremely compressed. It is rarely used while receiving. In addition, because the aluminum alloy and rubber are used in contact with each other in terms of product specifications, it is considered that it is more realistic to use the surface electrical resistance value as a guide rather than the volume resistivity value. .

  On the other hand, for the above-described aluminum electrolytic corrosion evaluation (electric corrosion evaluation of aluminum alloy), the extruded product S1 for aluminum electrolytic corrosion evaluation having a cross-sectional shape as shown in FIG. Was made. These extrusion molded products S1 were assembled in an aluminum alloy sash 1 having a substantially L-shaped cross section as shown in the figure, and each treatment of salt spray, hot air drying, and leaving in a wet atmosphere was repeated. The corrosion state of the aluminum alloy sash 1 was visually evaluated in four stages. The thickness t1 of the sash 1 and the thickness t2 of the extruded product S1 were both 3 mm. Further, each of the above treatments is in accordance with the conditions of the automobile exterior corrosion test of “JASO M610-92”.

  Furthermore, in the evaluation results, “◎” indicates no change (appearance is very good), “○” indicates no corrosion (good appearance), “△” indicates slight corrosion (appearance is somewhat bad), and “×” indicates Represents a large amount of corrosion (appearance is very bad).

  As said aluminum alloy, the thing of a JIS6000 type | system | group alloy (Al-Mg-Si type) was used. Of course, JIS 3000 series alloys (Al-Mn series), 5000 series alloys (Al-Mg series), and 7000 series alloys (Al-Zn-Mg series) can be used. System or 6000 system.

  Further, the shrinkage is measured by extruding an extruded product S1 having a cross-sectional shape as shown in FIG. 1 under the blending of samples No. 1 to No. 15 and then cutting to a length of 800 mm immediately after vulcanization. The first step is 90 ° C./5 hours, the second step is 25 ° C./1 hour, the third step is −40 ° C./2 hours, the fourth step is 25 ° C./1 hour, and the first to fourth steps. The durability test up to 12 cycles is repeated for a total of 12 cycles, and the dimensional change rate in the longitudinal direction after the durability test of the initial stage and 12 cycles is calculated as shrinkage (%) based on the following formula (5). did.

As is apparent from Tables 1 to 3, the G * r value correlates with the surface electrical resistance value in the rubber composition having the same composition, but if it is 10 ⁶ (Ω) or more, the aluminum corrosion resistance is high. It is not good, and it can be seen that the aluminum alloy on the other side is corroded (electrically corroded) unless the value of G * r satisfies the formula (2) as in the comparative example. On the contrary, even if the surface electrical resistance value is in the range of 10 ⁴ (Ω) or more and less than 10 ⁶ (Ω) , G * r particularly satisfies the formula (2) as in Examples 1-7. This shows that the aluminum alloy is not corroded. As a result, the apparent activation energy Ea (× 10 ⁻¹ KJ / mol) of the complex viscosity is in the range of 50 ≦ Ea ≦ 230 , and the change rate G * r of the complex elastic modulus is 0.9 ×. It can be seen that the rubber composition satisfying (100−0.36C) ≦ G * r (%) is a rubber composition that does not corrode the aluminum alloy and has good processability.

  Furthermore, if the rubber composition has the same composition, the surface electrical resistance value of the crosslinked rubber is relatively less affected by the processing conditions of kneading. Rather, it can be seen that the proportion of the carbon black content has a greater influence on the surface electrical resistance value. In other words, the surface electric resistance value of the crosslinked rubber tends to be determined to some extent depending on the carbon black content.

  In particular, since Comparative Examples 1 to 3 have a small amount of carbon black, the relative distance between adjacent primary aggregates (aggregates) of carbon black contained in the rubber composition is increased, resulting in surface electrical resistance. The value tends to be relatively high.

  Here, when paying attention to the three types of kneading conditions shown in Table 4, since the rotational speed of the rotor is high in the order of A, B, and C, the temperature rise due to shearing of the carbon black compounded rubber material is fast, Aggregation tends to occur.

  As apparent from Tables 1 to 3, it is expected that the kneading method of A has poor rubber surface gloss, and carbon black is not locally dispersed (G * r is expressed by the formula (2)). To meet.) In Comparative Example 1, the surface electric resistance value shows a relatively high value. In this case, the electric circuit is formed in a portion where the rubber, the aluminum alloy, and the electrolyte solution are in contact with each other due to a relatively large aggregate of carbon black. Is formed (so-called local battery), and it is presumed that the aluminum alloy was corroded. Conversely, even if the amount of carbon black is relatively large as in Example 7, if a kneading method that disperses relatively evenly as in the kneading method of C, a relatively large aggregate of carbon black is formed. Since the amount is small (because G * r satisfies the formula (2)), even when the rubber of Example 7 is in contact with the aluminum alloy and the electrolyte solution, an electric circuit (local battery) is not formed, and the corrosion of the aluminum alloy Is presumed to be difficult to occur.

From the above, the corrosion of aluminum alloy (aluminum electric corrosion) is not only the amount of carbon black but also kneading in the region where the surface electrical resistance value of the crosslinked rubber is 10 ⁴ (Ω) or more and less than 10 ⁶ (Ω). It turns out that it is influenced by the generation | occurrence | production degree (dispersibility) of the comparatively big aggregate of carbon black depending on conditions.

As a result, there is naturally an optimum degree of dispersion (G * r) depending on the blending amount of carbon black. The value of G * r satisfies the formula (2) and the surface electrical resistance value is 10 as described above. It was found that a rubber in the range of ⁴ (Ω) or more and less than 10 ⁶ (Ω) was remarkably excellent in aluminum alloy resistance to corrosion.

  3 to 5 show specific examples of automobile sealing members extruded using the above rubber composition.

  FIG. 3 shows an example of a glass run 3 fitted and fixed to a door sash 2 made of an aluminum alloy. The door sash 2 is formed as a substantially channel-shaped cross section by, for example, a die casting method. Similarly, a plurality of seal lips 5 and 6 that are elastically contacted with the door glass G are integrally provided on the inner portion of the mounting base 4 having a substantially channel cross section, that is, the portion that receives the door glass G.

  Therefore, by using any one of the rubber compositions of Examples 1 to 7 described above as the material of the glass run 3 itself, the corrosion of the aluminum alloy door sash 2 that comes into contact with the glass run 3 is suppressed. Is done.

  FIG. 4 shows an example of a trunk lid weather strip 8 that is attached to the opening edge of the luggage room (trunk room) and elastically contacts the trunk lid 7 made of aluminum alloy.

  As shown in the figure, the trunk lid weatherstrip 8 includes a welt portion 10 having a substantially U-shaped cross section containing a cored bar 9 functioning as a mounting base, and a hollow seal lip formed integrally with the welt portion 10. 11, and a plurality of holding lips 13, 14 that integrally hold the trunk lid weather strip 8 in elastic contact with the flange portion 12 a on the vehicle body panel 12 side on the inner periphery of the welt portion 10. Protrusions are formed. When the trunk lid 7 is closed, the aluminum alloy trunk lid 7 (more precisely, the trunk lid inner panel) is elastically contacted with the seal lip 11 when the trunk lid 7 is closed. A sponge rubber obtained by foaming the rubber composition of any one of Examples 1 to 7 described above, and a welt portion 10 having a solid rubber of the rubber composition of any one of Examples 1 to 7 described above. Is formed. In this case, the vehicle body panel 12 to which the trunk lid weatherstrip 8 is attached may be made of either a steel plate or an aluminum alloy.

  Therefore, in this example, at least corrosion of the trunk lid 7 made of an aluminum alloy that comes into elastic contact with the seal lip 11 is suppressed.

  FIG. 5 shows an example of a front hood seal 16 of the rear hinge type and attached to the front edge of a hood (bonnet) 15 made of aluminum alloy.

  As shown in the figure, a front hood seal 16 is attached to a portion of the rear surface of the front edge portion of the hood 15 facing the left and right headlamp units 17, and the front hood seal 16 is attached when the hood 15 is closed. The headlamp unit 17 is brought into elastic contact with the headlamp unit 17 to prevent the generation of wind noise due to the vehicle traveling in the gap between the headlamp unit 17 and the hood 15.

  The front hood seal 16 includes a flat mounting base 18, a hollow seal lip 19, and a tongue-shaped top seal 20 protruding obliquely from the seal lip 19 of each of the first to seventh embodiments described above. Both of the rubber compositions are integrally molded, and the attachment base 18 is attached to the hood inner panel 15b made of aluminum alloy with a clip 21 made of resin, for example. When the hood 15 is closed, the seal lip 19 is in elastic contact with the front end of the aluminum alloy hood outer panel 15 a and the top seal 20 is in contact with the upper surface of the headlamp unit 17.

  Therefore, in this example, even if the front hood seal 16 is in contact with the hood outer panel 15a and the hood inner panel 15b made of aluminum alloy, corrosion of the hood outer panel 15a and the hood inner panel 15b is suppressed. .

  The glass run 3, the trunk lid weather strip 8, the front hood seal 16 and the like as the automobile seal members exemplified here are merely examples, and any other seal members may be used as long as they are in contact with the counterpart member made of aluminum alloy. Needless to say, the same applies to the part.

Cross-sectional explanatory drawing which shows the aluminum electrolytic corrosion evaluation method of the vulcanized rubber sample extruded. Explanatory drawing at the time of the surface electrical resistance value measurement of a vulcanized rubber sample. Sectional drawing which shows the shape of a glass run as an example of the sealing component for motor vehicles used in combination with an aluminum alloy. Sectional drawing which shows the shape of a trunk lid weather strip as another example of the sealing component for motor vehicles similarly used in combination with an aluminum alloy. Sectional drawing which shows the shape of a front hood seal as another example of the sealing component for motor vehicles similarly used in combination with an aluminum alloy.

Explanation of symbols

2 ... Aluminum alloy door sash 3 ... Glass run 7 ... Aluminum alloy trunk lid 8 ... Trunk lid weather strip 15 ... Aluminum alloy hood 16 ... Front hood seal

Claims (1)

An automotive seal member that is mounted on a part of a vehicle body and whose surface comes into contact with a counterpart member made of an aluminum alloy,
An automotive sealing member, characterized by being formed with a rubber composition that satisfies the following conditions (a) to (c).
(A) SRF type carbon black is blended in 110 to 190 phr in 100 phr of ethylene-α-olefin-nonconjugated diene copolymer rubber .
(A) The surface electrical resistance value when crosslinked by extrusion molding vulcanization is 10 ⁴ (Ω) or more and less than 10 ⁶ (Ω) .
(C) viscoelastic properties of the unvulcanized rubber composition was Cphr blending carbon black below (a), and this satisfies the (b).
(A) The apparent activation energy Ea (× 10 ⁻¹ KJ / mol) of the complex viscosity is 50 ≦ Ea ≦ 230.
(B) The complex elastic modulus change rate G * r is 0.9 × (100−0.36C) ≦ G * r (%).

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