JP2006249358A - Sponge rubber-forming composition, sponge rubber-formed material and weather strip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a contacting position of a coated body with the sponge rubber from causing a blackening phenomenon even by using the sponge rubber-formed material exhibiting a sealing effect by making a contact with a metallic coated material repeatedly and continuously for a long time. <P>SOLUTION: This weather strip is produced by a usual forming method of the blended material for the sponge rubber consisting of, by mass, 100 pts. of EPDM, 70 pts. of carbon black, 30 pts. of light weight calcium carbonate, 50 pts. of paraffin-based process oil, 1 pt. of stearic acid, 5 pts. of zinc oxide powder, 3 pts. of azodicaboxylic acid amide, 1.5 pts. of foaming assistant, 1.5 pts. of sulfur, 1.8 pts. of vulcanization accelerator (cyclohexylbenzothiazyl-sulfonamide), 0.3 pt. of vulcanization accelerator (zinc dibutylthiocarbamate) and 100 pts. of zeolite. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sponge rubber molding composition, a sponge rubber molding, and a weather strip. More specifically, the present invention relates to a sponge rubber molding composition for producing a sponge rubber molding that does not cause a blackening phenomenon at a contact portion even when it is in contact with a metallic paint coating body for a long period of time. The present invention relates to a rubber molded body and a weather strip for automobiles composed of such a sponge rubber molded body.

If you use an aluminum medicine can or pan for a long time, the bottom may become black. This phenomenon is called “aluminum blackening phenomenon”. This aluminum and oxygen in the air to produce a very thin film of Al ₂ O ₃ cause an oxidation reaction on the surface of aluminum, further Al ₂ O ₃ is the main cause may cause complex chemical reactions with the surrounding compound It is.

  A similar “blackening phenomenon” may occur at a location where a weather strip attached to an opening of an automobile contacts the vehicle body panel. Hereinafter, the blackening phenomenon of the vehicle body panel will be described.

  A weather strip is fitted and mounted on a sheet metal flange at the opening of an automobile for the purpose of waterproofing, soundproofing, dustproofing and the like. Several examples of the state of the weather strip attached to the periphery of the door of the automobile and the body panel will be described with reference to FIGS.

  FIG. 1 is a perspective view of an automobile equipped with a weather strip around a door. FIG. 2 is a cross-sectional view of the AA plane of FIG. An opening weather strip inner 3 is fitted and attached to the flange 2 of the vehicle body panel 1. The opening weather strip inner 3 is composed of a solid portion 4 and a sponge seal portion 5. Each time the front door 6F is opened and closed, the sponge seal portion 5 abuts against the panel of the front door 6F, and the door is opened and closed. At the same time as absorbing the impact, the effect of waterproofing, soundproofing, dustproofing, etc. is succeeded. On the other hand, an opening weather strip outer 7 is attached to the front door 6F. The opening weatherstrip outer 7 is composed of a solid part 8 and a sponge seal part 9. Each time the front door 6F is opened and closed, the sponge seal part 9 comes into contact with the vehicle body panel 1 to absorb the impact when the door is opened and closed. At the same time, the effect of waterproofing, soundproofing, dustproofing, etc. is succeeded.

  FIG. 3 is a cross-sectional view of the BB plane of FIG. An opening weather strip inner 12 is fitted and attached to the flange 11 of the vehicle body panel 10. The opening weatherstrip inner 12 is composed of a solid portion 13 and a sponge seal portion 14. Each time the front door 6F is opened or closed, the sponge seal portion 14 abuts against the panel 15 of the front door 6 to open or close the door. At the same time as absorbing the impact of the water, it is effective in waterproofing, soundproofing, dustproofing and the like. On the other hand, an opening weather strip outer 17 is fitted and attached to the retainer 16 formed integrally with the panel 15 of the front door 6F. The opening weather strip outer 17 is composed of an attachment base 18 and a sponge seal portion 19. Each time the front door 6F is opened and closed, the sponge seal portion 19 comes into contact with the vehicle body panel 10 to cause an impact when the door is opened and closed. At the same time as absorbing water, the effect of waterproofing, soundproofing, dustproofing, etc. is effective. Reference numeral 20 denotes a front door glass.

  FIG. 4 is a cross-sectional view of the CC plane of FIG. An opening weather strip outer 22 is attached to the F panel of the front door 6 by a clip 21. The opening weather strip outer 22 is composed of an attachment base 23 and a sponge seal portion 24. Each time the front door 6F is opened and closed, the sponge seal portion 24 abuts on the pillar 25, and an impact at the time of opening and closing the door is generated. At the same time as absorption, the effect of waterproofing, soundproofing, dustproofing, etc. is effective. On the other hand, an opening weather strip inner 27 is fitted and attached to the flange 26 provided in the pillar 25. The opening weather strip inner 27 is composed of a solid portion 28 and a sponge seal portion 29. Each time the front door 6F is opened / closed, the sponge seal portion 29 abuts against the panel of the front door 6 to open and close the door. At the same time as absorbing the impact, the effect of waterproofing, soundproofing, dustproofing, etc. is succeeded. Similarly, a weather strip is also provided on the rear door 6R, but the structure and operation are the same, and thus the description thereof is omitted.

  The weather strip having the structure as described above is attached to the periphery of the opening of the automobile. Whenever the opening is opened and closed, the sponge seal portion of the weather strip is brought into contact with the vehicle body panel. In addition, it absorbs the impact when the door is opened and closed, and at the same time, it is effective for waterproofing, soundproofing and dustproofing.

  In addition, although the method of attaching a weather strip with a retainer and a clip was shown in the figure, there are other methods such as fitting to a sash, and the method of attaching a weather strip is not limited in the present invention.

  During most of the period of use of the automobile, the sponge seal part of the weather strip is in contact with the vehicle body panel, and the length of the automobile strip is about 4 meters in a normal passenger car. In addition, it is assumed that the number of times of repeated contact is several tens of thousands.

  In recent years, during use of an automobile for a long time, the coating film where the sponge seal portion contacts the vehicle body panel may change to black. In particular, this problem frequently occurs in coating films that are metallic. This fact has been confirmed by a comparison test between a steel sheet coated with metallic paint and a steel sheet not coated with metallic paint. In addition, as a result of a comparison test between sponge rubber and solid rubber, it has been confirmed that this phenomenon occurs in sponge rubber, that is, the foaming agent used in the production of sponge rubber has an effect.

  A method for solving this problem has been proposed, and Japanese Patent Application Laid-Open No. 9-310036 discloses an automotive metallic topcoat film in which the content of aluminum pigment in the metallic base is 0.05% by weight or less. Disclosure.

  However, this conventional method is a viewpoint from the improvement of the paint for automobiles, and is difficult and impractical for a weather strip supplier who does not manufacture automobile paints directly and an automobile manufacturer.

No. 9-310036

  The problem to be solved by the present invention is that, even when a sponge rubber molded body that is in contact with a metallic coated coating body and exhibits a sealing effect is continuously used over a long period of time, the coated body is in contact with the sponge rubber molded body. This is to prevent blackening from occurring at the contact point.

  Another problem to be solved by the present invention is a sponge rubber molded body that exerts a sealing effect by abutting with a coated body coated with metallic paint, and the coated body is a sponge even when used repeatedly for a long time. It is an object of the present invention to provide a composition for producing a rubber molded body in which a blackening phenomenon does not occur at a location where the rubber molded body comes into contact.

  Still another problem to be solved by the present invention is a sponge rubber molded body that exerts a sealing effect by abutting with a coated body coated with metallic paint. The present invention proposes to use a sponge rubber molded body that does not cause a blackening phenomenon at a portion in contact with the sponge rubber molded body as a weather strip for an automobile.

  The present inventor first theoretically analyzed the influence of the foaming agent used for the production of sponge rubber on the automobile coating film in order to formulate means for solving the problems.

  FIG. 5 is a cross-sectional view showing an example of a coating film of an automobile. On the automobile body steel plate 30, an undercoat film 31 of about 20 μm of a cationic electrodeposition paint using a water-based paint as a main colorant is formed. On the surface of the undercoat film 31, an intermediate coat film 32 of about 1 to 2 μm is formed. On the surface of the intermediate coating film 32, a metallic coating film 33 of about 20 μm is formed. A clear coating 34 of about 50 μm or less is formed on the surface of the metallic coating 33. In this way, the steel sheet 41 has a coating having a total thickness of about 0.1 mm or less.

  The clear coating film 45 does not include an aluminum foil or the like, and is a solid color that is color-designed by blending white and various coloring pigments. Resins used for solid colors are usually acrylic melamine resins, melamine alkyd resins, and the like. The clear coating film 45 has a coating film hardness, adhesion, flexibility, resistance, etc. as the coating film physical quality, such as the coating surface appearance quality, smoothness, and feeling of holding. As the chemical quality of the coating film such as impact resistance and weather resistance, it is required that the coating film has excellent water resistance, moisture resistance, chemical resistance, corrosion resistance, and the like.

  The metallic coating 44 is mainly a scale-like aluminum foil, aluminum flake, or a coating of aluminum foil or aluminum flake coated with a pigment, usually dispersed in an acrylic melamine resin. It is a coated film.

By the way, aluminum used in metallic paint is a metal that is inherently soluble in acids and alkalis and easily corroded. In general, aluminum is considered to be resistant to rust because a thin film of oxide (Al ₂ O ₃ ) that is not attacked by acid or alkali is formed in air to protect the inside. However, the Al ₂ O ₃ film naturally formed in the air is extremely thin and has a thickness of at most 5 μm and does not have sufficient corrosion resistance.

Therefore, anodization of aluminum is performed to form an Al ₂ O ₃ corrosion-resistant film having a thickness of 5 to 100 μm. Since the coating immediately after electrolytic oxidation is porous with γ-Al ₂ O ₃ , it is treated with 4-5 atmospheres of steam for 30 to 60 minutes to form γ-Al ₂ O ₃ —H ₂ O _2. Has been processed.

It is unclear whether the aluminum foil or flakes used in the metallic paint are formed by treating aluminum in this way to form a corrosion-resistant film of γ-Al ₂ O ₃ —H ₂ O ₂ having a thickness of 5 to 100 μm. Although it is obvious, even if a γ-Al ₂ O ₃ —H ₂ O ₂ corrosion-resistant film having a thickness of 5 to 100 μm formed on the surface of aluminum is used, The following phenomenon may occur.

Aluminum is a good conductor with a metallic luster appearance and high flexibility, specific gravity (d ²⁰ ) of about 2.7, and coefficient of thermal expansion (10 ⁻⁴ K ⁻¹ ) of 0.2313, The corrosion-resistant coating of γ-Al ₂ O ₃ —H ₂ O ₂ is colorless and transparent in appearance, extremely hard, specific gravity (d ²⁰ ) of about 4.0, and coefficient of thermal expansion (10 ⁻⁴ K ⁻¹ ) of 0.0080. And it has the physical property of an insulator.

Thus, the corrosion-resistant film of aluminum and γ-Al ₂ O ₃ —H ₂ O ₂ is a completely different material and is in a state where they are bonded together. Therefore, it is conceivable that the corrosion resistance of the hard γ-Al ₂ O ₃ —H ₂ O ₂ is cracked or delaminated due to the difference in dimensional change due to the cold cycle due to long-term use, resulting in deterioration of the corrosion resistance. .

  By the way, in order to produce a molded product of sponge rubber, a foaming agent, a foaming aid, and a vulcanization accelerator are blended as additives.

As a foaming agent, the following are illustrated as an inorganic type foaming agent.
(1) Ammonia carbonate, to be exact, double bicarbonate (NH ₄ ) HCO ₃ = (NH ₄ ) (NH ₂ ) CO _{2 of} ammonia bicarbonate and ammonium carbide. This generates carbon dioxide (CO ₂ ), ammonia (NH ₃ ), and water.
(2) Sodium bicarbonate (NaHCO ₃ ). This generates carbon dioxide and water, leaving sodium carbonate as a solid.
(3) An equimolar mixture of sodium nitrite (NaNO ₂ ) and ammonium chloride (NH ₄ Cl).
(4) Nitrourea (NH ₂ CONHNO ₂ )

Examples of the organic foaming agent include the following.
(I) Dinitroso Pentamethylene Tetramine
Abbreviation: DPT or DNPT
Chemical formula: (CH ₂ ) ₅ N ₄ (NO) ₂
Generated gas components: N ₂ 91.4%, CO 1.8%, Others 5.8%
Generated gas amount: 200 to 270 mL / g

(B) N, N'-Dimethyl-N, N'-Dinitrosoterephthalamide
Chemical formula: (CH ₂ ) ₅ N ₂ (NO) ₂ (CO) ₂ (C ₆ H ₄ )
Components of generated gas: N ₂
Generated gas volume: 115 mL / g

(C) Benzenesulfonyl-hydraside
Chemical formula: C ₆ H ₅ —SO ₂ NHNH ₂
Components of generated gas: N ₂
Generated gas volume: 130 mL / g

(D) (PP ′)-oxybis (benzenetoluenesulfonylhydrazide) (PP ′) Oxybis (benzenesulfonyl-hydraside)
Chemical formula: NH ₂ NHSO ₂ —C ₆ H ₄ —O—C ₆ H ₄ —SO ₂ NHNH ₂
Generated gas components: N ₂ and water generated gas amount: 120 to 125 mL / g

(E) Azobisiso butyronitril
Chemical _{formula: NCC (CH 3) 2 N} = N (CH 3) 2 CCN
Components of generated gas: N ₂
Generated gas amount: 130 to 155 mL / g

(F) Azodicarbonamide
Chemical formula: H ₂ N—CO—N═N—CO—NH ₂
Generated gas components: N ₂ , CO, CO ₂ ,
Generated gas amount: 250 to 300 mL / g

As a foaming aid,
(A) Urea foaming aid The urea foaming aid is used for both DPT and AC.
(B) When DPT is used for the organic foaming auxiliary rubber, salicylic acid may be used. Fatty acids such as stearic acid and lauric acid that are useful as vulcanization accelerators are also effective assistants.
(C) Metal salt foaming aids are mainly used in AC, and salts of fatty acids such as zinc, calcium, lead and barium are mainly used.

  In summary, most inorganic or organic foaming agents themselves have functional groups that change to ammonia or urea, or generate ammonia or urea by thermal decomposition during the molding process. I understand that.

By the way, when a reaction such as A (1 mol) + B (1 mol) → AB (1 mol) + H ₂ O (1 mol) is performed, in terms of stoichiometry, AB1 mol and 1 mol of water are generated from A1 mol and B1 mol. In the actual reaction, a mixture of A, B, AB, and water is produced as if the reaction stopped halfway. In this case, the reaction does not depend on the left side or the right side unilaterally, although it varies depending on the conditions (for example, temperature) when the reaction is performed. This is the so-called chemical equilibrium theory.

This chemical equilibrium theory is applied to, for example, the reaction between DPT and urea as a foaming aid. The reaction when urea is added to DPT and thermally decomposed in the rubber composition is as follows:
3 (CH ₂ ) ₅ N ₄ (NO) ₂ + 8CO (NH ₂ ) ₂ → 5/2 (CH ₂ ) ₆ N ₄
+ 6N ₂ + 6H ₂ O + 4NH ₂ CONHCOHH ₂
Also in this case, stoichiometrically, from 3 moles of DPT and 8 moles of urea, 5/2 moles of (CH ₂ ) ₆ N ₄ , 6 moles of N ₂ , 6 moles of water, burette (NH ₂ CONHCOHH ₂ ) is produced in 4 moles, but in the actual reaction, a mixture of DPT, urea, (CH ₂ ) 6 N ₄ , N ₂ , water and burette (NH ₂ CONHCOHH ₂ ) Has been generated.

  In view of this, when the above-described inorganic and organic foaming agents are thermally decomposed in the rubber composition, thermal decomposition occurs, and carbon dioxide gas, ammonia, or a gas that changes to ammonia is generated. It can be seen that inorganic and organic foaming agents or foaming aids containing functional groups that change ammonia remain in the system.

By the way, the corrosion resistant coating of γ-Al ₂ O ₃ —H ₂ O ₂ formed on the surface of aluminum foil or flakes used in metallic paints is a completely different material from metallic aluminum, As described above, it is considered that the corrosion resistance coating of hard γ-Al ₂ O ₃ —H ₂ O ₂ is cracked or delaminated due to the difference in dimensions due to the cycle, and the corrosion resistance is lowered. Further, as described above, aluminum is a metal that is inherently soluble in acids and alkalis and easily corrodes.
Therefore, cracks occur on the surface of the aluminum foil or flakes used in the metallic paint, or delamination occurs, and the clear coating 13 that protects the metallic coating 12 is destroyed for some reason. When ammonia is present, it is considered that the ammonia (NH ₃ ) erodes the aluminum foil or flakes having reduced corrosion resistance due to the reaction with water.

Moreover, even if the clear coating film 13 protecting the metallic coating film 12 is not broken due to a physical cause, the above-described inorganic and organic foaming agents are generated by thermal decomposition during the sponge manufacturing process. The clear coating film 13 is chemically formed by a synergistic chemical action with ammonia (NH ₃ ) and the inorganic and / or organic foaming agent and foaming auxiliary agent remaining in the reaction system clarified by the chemical equilibrium theory. And a bore is formed between the clear paint film and the metallic paint film immediately below the clear paint film. As a result, the blackening phenomenon occurs in the same manner.

In addition, when the surface is cracked or delaminated, the corrosion resistance is reduced, and the clear coating 13 protecting the metallic coating 12 is destroyed for some reason, naturally, the aluminum foil or flakes are directly formed. combine with oxygen in the air is considered to generate a very thin film of Al ₂ O ₃ cause an oxidation reaction, further Al ₂ O ₃ undergoes complex chemical reactions with the surrounding compound, causes blackening . It is conceivable that this oxidation phenomenon and the above-described corrosion phenomenon occur in combination, and the blackening phenomenon is further promoted.

  In order to prevent the blackening phenomenon of the aluminum foil or flakes used in the metallic paint described above, the inorganic or organic foaming agent described above is used in the ammonia and reaction system generated by thermal decomposition during the sponge manufacturing process. The remaining inorganic or organic foaming agent, or a gas or compound that corrodes aluminum such as urea as a foaming aid is removed.

  The inventors added inorganic porous adsorbents such as zeolite and activated carbon, which have been conventionally used as adsorbents, to the rubber compound in the process of producing sponge rubber moldings, and in the initial stage of pyrolysis The adsorption effect was confirmed. As a result, inorganic porous adsorbents such as zeolite, activated carbon, sepiolite, hydrotalcite, etc., especially in the case of ammonia, it is basic, so the inorganic porous material with modified surface and added acidic functional group It was confirmed that the adsorbent was effective, and the present invention was completed.

  The inorganic porous adsorbent used in the present invention is one conventionally used for gas adsorption such as zeolite, activated carbon, sepiolite, hydrotalcite, ceramics. Therefore, the detailed description regarding the inorganic porous adsorbent is omitted.

  The compounding amount of the inorganic porous adsorbent used in the present invention is 5 to 200 phr, preferably 60 to 150 phr, and most preferably 90 to 120 phr in a sponge rubber composition containing a normal rubber additive. . However, this blending ratio should be determined in consideration of the type of foaming agent and foaming aid, the amount of generated gas adsorbed, the viscosity of the unvulcanized fabric, and various physical properties.

  By setting the blending amount of the inorganic porous adsorbent in the present invention to 5 to 200 phr, the residual amount of ammonia and urea after molding can be reduced to 300 mg / kg or less, and the blackening phenomenon of coating due to corrosion of aluminum. Can be prevented.

  In this invention, when the compounding quantity of an inorganic type porous adsorption agent is 5 phr or less, the adsorption effect of ammonia gas or urea is not good. On the other hand, when the blending amount of the inorganic porous adsorbent is 200 phr or more, it is not preferable because molding processability is deteriorated.

  In the present invention, when the inorganic porous adsorbent is zeolite, the most preferable example of the foaming agent and the foaming aid for obtaining a product having the same specific gravity is ADCA: foaming aid = 3 phr: 1.5 phr. . In the case of OBSH, 6 phr, and in the case of DPT, DPT: foaming aid = 2.5 phr: 2.5 phr.

Therefore, the above problem is solved by the following.
(1) At least one inorganic porous adsorbent is blended in an amount of 5 to 200 phr in a sponge rubber compounded with a foaming agent, a foaming aid, and a normal rubber additive, and corrosion of metal aluminum after molding A sponge rubber composition in which the residual amount of the substance is 300 mg / kg or less.

(2) In (1) above, the metal aluminum corrosive substance is ammonia and / or urea.

(3) Forming the sponge rubber composition of (1) or (2) above to form a sponge rubber molded body.

(4) Use the sponge rubber molded product of (1) or (2) above as a weather strip for automobiles.

  According to the first aspect of the present invention, there is provided a composition for a sponge rubber which can be subjected to a commercial transaction as an independent product with a residual amount of the metal aluminum corrosive substance after molding of 300 mg / kg or less.

  According to the invention of claim 2, since the metal aluminum corrosive substance generated when the sponge rubber containing the foaming agent and the usual rubber additive is pyrolyzed is mainly ammonia and / or urea, the corrosion of the metal aluminum is prevented. It can be prevented beforehand.

  According to the invention of claim 3, the use is expanded because the blackening phenomenon of the contact portion does not occur even if the metal or plastic coated with the sponge is contacted repeatedly and continuously as a sealing material for a long time after the sponge rubber molding. .

  According to the invention of claim 4, by using it as a weather strip for an automated person after molding, the blackening phenomenon of the contact portion of the vehicle body panel can be achieved even if it is repeatedly contacted with the metallic coated vehicle panel for a long period of time. Does not occur.

  According to the first to fourth aspects of the present invention, after molding, the residual amount of ammonia gas or urea is 300 mg / kg or less, so that the blackening phenomenon of the paint due to corrosion of aluminum can be prevented.

  Hereinafter, the best mode for carrying out the invention will be described with reference examples and examples.

A formulation for producing a corner weatherstrip with the following composition was prepared without the addition of zeolite.
Component part EPDM (“EPDM EP35” manufactured by Nippon Synthetic Rubber Co., Ltd.) 100
Carbon black (Tokai Carbon "FEF") 70
Light calcium carbonate (Shiraishi Kogyo) 30
Paraffinic process oil (made by Idemitsu) 50
Stearic acid (made by Nippon Oil & Fats) 1
Zinc flower (manufactured by Shodo Chemical) 5
Foaming agent (ADCA) (“AC # 3” manufactured by Eiwa Kasei) 3
Foaming aid (Eiwa Chemical Co., Ltd. “M3”) 1.5
Zeolite 100
Sulfur (Tsurumi Chemical) 1.5
Vulcanization accelerator (cyclohexyl benzothiazylsulfonamide) 1.8
Vulcanization accelerator (zinc dibutyl thiocarbamate) 0.3

    The formulation of Reference Example 1 was molded under the same conditions as when producing a weatherstrip, and the remaining amounts of ammonia and urea in the rubber were measured. This test was repeated 5 times, and the average value was 100 mg / kg.

  As described above, after molding, by blending 5 to 200 phr of at least one inorganic porous adsorbent with a sponge rubber compounded with a foaming agent, a foaming aid, and a normal rubber additive. Since the residual amount of ammonia gas or urea is 300 mg / kg or less, the blackening phenomenon of the paint due to corrosion of aluminum does not occur.

The perspective view which shows an example of the position attached to the weatherstrip vehicle body. AA sectional drawing of FIG. BB sectional drawing of FIG. CC sectional drawing of FIG. Sectional drawing which shows an example of the coating film of a motor vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body panel 2 Flange 3 Opening weather strip inner 4 Solid part 5 Sponge seal 6F Front door 6R Rear door 7 Opening weather strip outer 8 Solid part 9 Sponge seal part 10 Car body panel 11 Flange 12 Opening weather strip inner 13 Solid part 14 Sponge seal part 15 Front Door Panel 16 Retainer 17 Opening Weather Strip Outer 18 Mounting Base 19 Sponge Seal 20 Front Door Glass 21 Clip 22 Opening Weather Strip Outer 23 Mounting Base 24 Sponge Seal 25 Pillar 26 Flange 27 Opening Weather Strip Inner 28 Solid Part 29 Sponge Seal 30 Steel plate for automobile body 31 Undercoat film 32 Intermediate coat 33 metallic coating film 34 clear coating film

Claims (4)

At least one inorganic porous adsorbent is compounded in an amount of 5 to 200 phr in a sponge rubber compounded with a foaming agent and a usual rubber additive, and the residual amount of the metallic aluminum corrosive substance after molding is 300 mg / A sponge rubber composition having a weight of kg or less. The sponge rubber composition according to claim 1, wherein the metallic aluminum corrosive substance is ammonia and / or urea. A sponge rubber molded article obtained by molding the sponge rubber composition according to claim 1. An automotive weather strip comprising the sponge rubber molded article according to claim 1.

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