JP2017125103A - Water cut-off material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water cut-off material which has high water cut-off performance even if the compressive stress is low and facilitates an operation when arranging at an arrangement part, as a water cut-off material which is sandwiched between two objects and is compressed and used in a vehicle, a building or the like.SOLUTION: There is provided a water cut-off material constituted by a cross-linked foam body including a rubber component including an ethylene-α-olefin-nonconjugated diene copolymer rubber such as EPDM, a compatibilizer having a hydrophilic group and a hydrophobic group and a filler, wherein the amount of the compatibilizer is set to 5 to 45 pts.wt. based on 100 pts.wt. of the rubber component and the 50% compression stress is set to 40 to 85 kPa.SELECTED DRAWING: None

Description

  The present invention relates to a water-proof sealing material.

  2. Description of the Related Art Conventionally, in vehicles and buildings, a waterproof rubber sealing material between two objects is made of a crosslinked rubber sponge. As a sealing material made of a crosslinked rubber sponge, there are a weather-resistant and heat-resistant ethylene / propylene / diene rubber (EPDM) type.

The waterproof rubber sealant made of crosslinked rubber sponge is compressed in the gap for water stoppage and adheres to two objects with repulsive force to exert water stoppage. To improve waterstop, increase the repulsive force of the sealant. There is a need.
However, if the repulsive force of the sealing material is increased for the purpose of improving the water-stopping property, the compressive stress also increases, and a large force is required at the time of deformation when placing the sealing material on the installation part, and the installation workability of the sealing material is Become inferior.

JP 2001-316538 A

  This invention is made | formed in view of the said point, Comprising: It aims at provision of the water stop sealing material which has high water stop even if a compressive stress is low.

  The invention of claim 1 is a water-stop seal comprising a rubber component containing an ethylene / α-olefin / non-conjugated diene copolymer rubber, a compatibilizing agent having a hydrophilic group and a hydrophobic group, and a crosslinked foam containing a filler. The amount of the compatibilizer is 5 to 45 parts by weight with respect to 100 parts by weight of the rubber component, and 50% compressive stress (JIS K7220) is 40 to 85 kPa.

  The invention of claim 2 is characterized in that, in claim 1, the compatibilizing agent having a hydrophilic group and a hydrophobic group is a maleic anhydride-modified polyolefin resin.

  The invention of claim 3 is characterized in that, in claim 1 or 2, the filler contains both clay and carbon.

  Invention of Claim 4 contains softener in addition to the said filler in any one of Claim 1 to 3, The addition amount of the said filler and the said softener is 100 weight part of said rubber components. 70 to 250 parts by weight, wherein the filler and the softener are contained in a ratio of 65:35 to 50:40.

  According to the present invention, a filler such as a filler is compatibilized by mixing a compatibilizer having a hydrophilic group and a hydrophobic group with a polymer chain of ethylene / α-olefin / non-conjugated diene copolymer rubber. The water-resistant sealing material made of crosslinked foam is coated with a solubilizing agent, and the mechanical strength of the sealing material is increased. The filler on the surface of the sealing material is also coated (in a micellar state), so that the surface of the sealing material has good adhesion to the other object Rise. Moreover, since it is assumed that the hydrophilic group is also present on the surface side of the sealing material when it comes into contact with water, the interaction works at the interface with the partner object through the water, and it adheres to the water pressure. The power to continue increases. Accordingly, the water-proof sealing material of the present invention can have a high water-stopping property even when the compressive stress is low.

It is a figure which shows the water stop holding pressure measuring method.

Hereinafter, embodiments of the present invention will be described. The water-stop sealing material of the present invention comprises a cross-linked foam containing a rubber component containing an ethylene / α-olefin / non-conjugated diene copolymer rubber, a compatibilizing agent having a hydrophilic group and a hydrophobic group, and a filler. . The apparent density (JIS K7222) of the water-proof sealing material is preferably 0.03 to 0.3 g / cm ³ , and the 50% compressive stress (JIS K7220) is preferably 40 to 85 kPa, and more preferably 50 to 80 kPa.

  The ethylene / α-olefin / non-conjugated diene copolymer rubber is composed of a copolymer of ethylene, an α-olefin, and a non-conjugated diene.

  Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, Examples thereof include α-olefins having 3 or more carbon atoms such as 1-tetradecene and 1-pentadecene.

  Examples of the non-conjugated diene include 1,4-pentadiene, 1,4-hexadiene, 1,6-octadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 2-methyl-1, Examples include 5-hexadiene, 6-methyl-1,5-hexadiene, cyclohexadiene, dicyclohexadiene, 5-methylene-2-nobornene, 5-vinyl-2-nobornene, and 5-ethylidene-2-nobornene.

  The ethylene / α-olefin / non-conjugated diene copolymer rubber is particularly preferably ethylene-propylene-diene copolymer rubber (EPDM). The content of the non-conjugated diene is preferably 2 to 20% by weight, more preferably 3 to 15% by weight. By setting the content of the non-conjugated diene within the above range, physical properties such as tensile strength, elongation at break, and compression set can be improved.

The rubber component may contain other rubber together with the ethylene / α-olefin / non-conjugated diene copolymer rubber. Examples of other rubbers include natural rubber (NR), synthetic natural rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), butyl rubber (IIR), and nitrile rubber (NBR). ), Ethylene propylene rubber (EPM), chlorosulfonated polyethylene rubber (CSM), acrylic rubber (ACM), silicone rubber, fluorine rubber and the like. The amount of other rubber in 100 parts by weight of the rubber component is such that rubber having a double bond in the main chain such as NR and SBR deteriorates heat resistance and weather resistance, and CSM, NBR, silicone rubber, fluoro rubber since rubber hardly compatible with the EPDM is hardly lowered physical properties such as tensile strength as long as the state in which other rubber therein is dispersed as a matrix of EPDM as, the amount that contains 30 parts by weight or less More preferably, it is 100 parts by weight of ethylene / α-olefin / non-conjugated diene copolymer rubber (0 parts by weight of other rubber).

The compatibilizing agent having a hydrophilic group and a hydrophobic group is not particularly limited as long as it is a compound showing compatibility or affinity for the incompatible ethylene / α-olefin / nonconjugated diene copolymer rubber and the filler. . Specific compatibilizers include hydrogenation of a copolymer comprising a terminal block mainly composed of at least two vinyl aromatic compounds and an intermediate polymer block mainly composed of at least one conjugated diene compound. Examples thereof include a maleic anhydride-modified hydrogenated block copolymer, a maleic anhydride-modified ethylene-α / olefin (non-conjugated diene) copolymer rubber, and a maleic anhydride-modified polyolefin resin. Among these, a maleic anhydride modified product is preferable.
The maleic anhydride modified product is a copolymer of α-olefin and maleic anhydride. The α olefin is preferably an α olefin having 8 or less carbon atoms, and examples thereof include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and the like. Among them, maleic anhydride-modified propylene using propylene as an α olefin is preferable. The amount of the compatibilizer is preferably 5 to 45 parts by weight with respect to 100 parts by weight of the rubber component. In the case where the addition amount is less than 5 parts by weight, the water-stopping property cannot be obtained. When the addition amount exceeds 45 parts by weight, moldability such as rubber kneading and foaming uniformity is deteriorated.

  Filler is inorganic filler such as calcium carbonate, talc, magnesium hydroxide, mica, clay, aluminum hydroxide, magnesium hydroxide, barium sulfate, silicic acid, titanium oxide, bentonite, carbon black, mica, glass fiber, wood powder, etc. Materials can be mentioned. The amount of the filler is preferably 40 to 140 parts by weight with respect to 100 parts by weight of the rubber component. If it is less than 40 parts by weight, the workability, the dimensional stability and strength of the product are deteriorated, and if it exceeds 140 parts by weight, the adhesiveness is lowered and the water stoppage is deteriorated.

Examples of other components include a softener, a crosslinking agent, and a foaming agent.
The softening agent may be any of vegetable oils such as lauric acid, ricinoleic acid, valtimic acid, cottonseed oil, soybean oil, castor oil, and palm oil, or mineral oils such as paraffinic, naphthenic, and aromatic oils. The amount of the softening agent is preferably 30 to 110 parts by weight with respect to 100 parts by weight of the rubber component. When the amount is less than 30 parts by weight, the kneadability is deteriorated such that the composition is granular and does not form a lump.
The total amount of filler and softener added is preferably 70 to 250 parts by weight per 100 parts by weight of the rubber component. Moreover, 65: 35-50: 40 is preferable as the mixture ratio of a filler and a softener. By setting the total amount and ratio of the filler and the softener to be in the above ranges, the compatibility is enhanced and the moldability such as rubber kneading is excellent.

  As the crosslinking agent, sulfur or an organic peroxide is used. Sulfur is used for sulfur cross-linking and organic peroxide is used for peroxide cross-linking. Examples of organic peroxides include dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, and t-butylcumyl peroxide. Is mentioned. The amount of the crosslinking agent is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the rubber component. It is preferable to use a crosslinking accelerator and a crosslinking aid together with the crosslinking agent.

Examples of the cross-linking accelerator include benzothiazyl disulfide, 2-meltcaptobenzothiazole, dipentamethylenetyrium tetrasulfide, tetramethyltyrium disulfide, and zinc oxide.
Examples of the crosslinking aid include divinylbenzene, ethylene dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, and the like.

As the foaming agent, an organic or inorganic foaming agent can be used.
Examples of the organic blowing agent include azodicarboxylic acid amide (ADCA), barium azodicarboxylate, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, N, N′-dinitrosopentamethylenetetramine, N, N′-dimethyl-N, N′-dinitrosotephthalamide, trinitrosotrimethyltriamine, 4,4′-oxybis (benzenesulfonylhydrazide), paratoluenesulfonylhydrazide, diphenylsulfone-3,3′-disulfonylhydrazide, 2 , 4-Toluenedisulfonyl hydrazide, p, p-bis (benzenesulfonyl hydrazide) ether, benzene-1,3-disulfonyl hydrazide, allyl bis (sulfonyl hydrazide), p-toluylene sulfonyl semicarbazide, 4,4 ′ Oxybis (benzenesulfonyl semicarbazide), trichloromonofluoromethane, dichlorodifluoromethane monofluoromethane, and the like.

Examples of the inorganic foaming agent include sodium hydrogen carbonate, ammonium hydrogen carbonate, sodium carbonate, ammonium carbonate, sodium nitrite, ammonium nitrite, sodium borohydride and the like.
The amount of the foaming agent is preferably 5 to 100 parts by weight with respect to 100 parts by weight of the rubber component.
Moreover, it is preferable to use a foaming aid together with the foaming agent. Examples of the foaming aid include urea compounds, organic compounds, inorganic salts, and the like.
Furthermore, you may add a processing aid, a coloring agent, an anti-aging agent, etc. as other components. Examples of processing aids include stearic acid and palmitic acid.

In the production of the water-stop sealing material comprising the crosslinked foam of the present invention, first, a rubber component, a compatibilizing agent, a filler and the like are primarily kneaded with a Banbury mixer, a kneader or the like. In that case, a crosslinking agent, a crosslinking accelerator, a crosslinking aid, a foaming agent, and a foaming aid are not included. The primary kneading conditions are preferably a temperature of 50 to 180 ° C. and a kneading time of 3 minutes to 30 minutes. Thereafter, a cross-linking agent, a cross-linking accelerator, a cross-linking aid, a foaming agent, a foaming aid and the like are added to the obtained primary kneaded product, followed by secondary kneading. The secondary kneading conditions are preferably a temperature of 20 ° C. to 80 ° C. and a kneading time of 3 minutes to 30 minutes. The obtained secondary kneaded product is formed into a desired shape by a calendar molding machine, an extrusion molding machine or the like. Then, it accommodates in a bridge | crosslinking / foaming metal mold | die, performs primary bridge | crosslinking / foaming and secondary bridge | crosslinking / foaming in order, and obtains a bridge | crosslinking foam. The primary crosslinking / foaming is preferably 100 ° C. to 160 ° C. and 3 minutes to 20 minutes. Secondary crosslinking / foaming is preferably performed at 160 ° C. to 220 ° C. for 5 minutes to 20 minutes. Thereafter, a water-stop sealing material made of a ring or the like is obtained by punching or the like. The annular shape is determined according to the location to be used, such as a triangle, a quadrangle, or a circle.
The water-proof sealing material of the present invention is excellent in water-proofing and airtightness, and is particularly suitable as a sealing material for vehicle lamps. The sealing material in the vehicular lamp is used in a position between the lamp member and the lens casing, and achieves airtight waterproofing inside the lens casing. That is, the sealing material in the vehicular lamp is required to have airtightness that prevents moisture from entering the housing and water-stopping property that suppresses (prevents) condensation. Since the water-stop sealing material of the present invention is a foam, it is maintained in a compressed state at the lamp member fitting portion to ensure airtightness, and the adhesion with the mating member is improved. It is possible to prevent dew condensation due to intrusion.

The crosslinked foams of the examples and comparative examples (sheets having a thickness of 5 mm) were prepared from the rubber raw materials shown in Table 1, and then punched into a circular ring having an outer diameter of 60 mm, an inner diameter of 40 mm, and a thickness of 5 mm, and the water-stopping property. A sealing material was produced. The materials used and the crosslinking / foaming conditions are as follows.
-Product name: EPT9090M, Mooney viscosity: 58 (125 ° C), diene content: 14.0% by weight, manufactured by Mitsui Chemicals-EPDM-2; Product name: EPT8030M, Mooney viscosity: 32 (100 ° C), diene content : 9.5 wt%, Mitsui Chemicals, compatibilizer-1; Product name: Umex 1010, maleic anhydride modified PP, melting point: 145 ° C., Sanyo Kasei Co., Ltd., compatibilizer-2; Product name: Licocene PP MA 6252 , Maleic anhydride modified PP, melting point: 140 ° C., Clariant inorganic filler-1; product name: Southeastern crown clay (particle size: 2 μm or less)
・ Inorganic filler-2; Seast G-SO, FEF carbon, manufactured by Tokai Carbon Co., Ltd. ・ Softener; Product name; Naphthenic process oil, product NS-100, Idemitsu Petroleum Co., Ltd./Crosslinking accelerator-1; Product name; Zinc oxide 2 types, Zinc Hana No. 1 (trade name, manufactured by Sakai Chemical Industry Co., Ltd.)
・ Processing aid: Product name: Made of stearic acid camellia, stearic acid, NOF ・ Foaming aid: Product name: Product name: Cell paste K-4, urea, manufactured by Eiwa Kasei Kogyo Co., Ltd. ・ Crosslinking agent: Product name; 80, sulfur, manufactured by Tochi Co., Ltd./crosslinking accelerator-2; product name Sunmix TT-75E, Thiraum-based crosslinking accelerator, Sanshin Chemical Co., Ltd./crosslinking accelerator-3; product name Sunmix M75-E, thiazole-based crosslinking accelerator Product name: Cellular D, DPT (N, N'-dinitrosopentamethylenetetramine), manufactured by Eiwa Kasei Kogyo Co., Ltd.

The primary kneading was performed using a kneader at a temperature of 160 ° C. and a kneading time of 5 minutes, and the secondary kneading was performed using a roll at a temperature of 50 ° C. and a kneading time of 10 minutes.
The primary crosslinking / foaming was performed at a temperature shown in Table 1 and a time shown in Table 1 with 70 g of the secondary kneaded material contained in a mold having an internal volume of 57 cm ³ .
Secondary crosslinking / foaming was carried out at the temperatures shown in Table 1 for the time shown in Table 1, using the same mold as the primary crosslinking / foaming.

Regarding the molding state, apparent density (g / cm ³ ), 50% compressive stress (kPa), and water-stopping holding pressure (kPa) of the water-stopping sealing material at the time of molding the crosslinked foamed body of each Example and each Comparative Example Evaluation and measurement were performed by the method shown in FIG. The evaluation and measurement results are shown in Table 1.
As for the molding state, the surface of the crosslinked foamed product after secondary crosslinking / foaming was visually judged, and when there were almost no voids, the evaluation was “◯”, and when there were many voids, the evaluation was “x”.
The apparent density was measured according to JIS K7222 for the crosslinked foam after secondary crosslinking and foaming.
The 50% compressive stress was measured according to JIS K 7220 for the crosslinked foam after secondary crosslinking and foaming. In Comparative Example 1, there were many voids, and the 50% compressive stress and the water stop holding pressure could not be measured.

About the water stop holding pressure, it uses the measuring apparatus 10 shown in FIG. 1 with respect to the water stop sealing material of each Example and each comparative example (except comparative example 1), and is as follows in a 23 degreeC thermostat. I went.
A test steel plate (70 × 150 mm) 13 is arranged on a steel bottom plate 11, and the water-proof sealing material of each example and each comparative example (outer diameter: 60 mm, inner diameter) is placed in the center on the upper surface of the test steel plate 13. A circular annular body 15 having a thickness of 40 mm and a thickness of 5 mm is disposed. The test steel plate 13 is coated with a polyester resin and a melamine resin paint (Neo-Amilak 6000 manufactured by Kansai Paint Co., Ltd.) using an iron plate having a thickness of 1 mm as a base material. A double-sided adhesive tape (product name: INOAC-430, manufactured by INOAC Corporation) 16 is affixed in an annular shape to the upper surface of the water-stop sealing material 15. Further, on the upper surface of the test steel plate 13, steel spacers (thickness 2.5 mm) 17 corresponding to 50% thickness of the water-stop sealing material 15 are arranged on both outer sides of the water-proof seal material 15.

  A top plate 19 made of a transparent acrylic plate (thickness: 10 mm) having the same size as the bottom plate 11 is disposed on the double-sided adhesive tape 16 on the upper surface of the water-stop sealing material 15, and bosses 21 erected at the four corners of the bottom plate 11. Then, the upper plate 19 is lowered until it collides with the spacer 17 to compress the water-proof sealing material 15. Thereby, the compression rate of the water-stop sealing material 15 is set to 50%. The height of the boss 21 is lower than the height of the spacer 17. The top plate 19 is provided with a leading end of a pressurizing pipe 22 penetratingly provided at a position directly above a central hole (center portion) of the water-stop sealing material 15, and the air supplied by the air compressor 23 is used for pressurization. The water can be supplied to the central hole of the water-proof sealing material 15 through the pipe 22. A pressure gauge 25 and a regulator 27 for adjusting the supply of air are provided between the air compressor 23 and the pressurizing pipe 22. The pressure gauge 25 has a measurement range of 2 to 50 kPa and a minimum memory of 2 kPa. The regulator 27 has an adjustment range of 0 to 100 kPa.

  After leaving the water-stopping sealing material 15 in a constant temperature room at 23 ° C. with 50% compression, ion-exchanged water is supplied into the water-stopping sealing material 15 from a bottle and the water-stopping sealing material 15. The inside is filled, and in that state, air is supplied into the water-stopping sealing material 15 at 2 kPa by the air compressor 23 and held at the same pressure for 5 minutes. When water does not leak from the interface between the lower end of the water-stop sealing material 15 and the test steel plate 13, the air pressure is further increased by 2 kPa and held at the same pressure for 5 minutes to check for water leakage. This was repeated and the maximum pressure without water leakage was taken as the water stop holding pressure.

Examples 1 to 4 are examples in which the ratio of EPDM-1 and EPDM-2 was kept constant, and the amount of compatibilizer-1 was changed. Example 5 was softened with an inorganic filler compared to Example 2. Example 6 in which the amount of the agent was reduced, Example 6 is an example in which the compatibilizer-1 in Example 3 was changed to the compatibilizer-2.
Comparative Example 1 is a comparative example in which the amount of compatibilizer-1 was 50 parts by weight (relative to 100 parts by weight of rubber component), which is larger than the range of the present invention, compared to Example 1, and the foamed state Since there were many voids and the foaming state was poor, any of the apparent density, the water stop holding pressure, and the 50% compressive stress could not be measured. Comparative Example 2 is a comparative example in which the amount of compatibilizer-1 is 3 parts by weight (relative to 100 parts by weight of rubber component), which is less than the range of the present invention, compared to Example 1, This is a comparative example in which no compatibilizing agent is contained in Example 1. Comparative example 4 is a comparative example in which 50% compression stress (JIS K7220) exceeds 85 kPa.

  Since Examples 1-6 have a 50% compressive stress lower than Comparative Examples 2-4 and a high water-holding pressure, they have a high water-stopping property even if the compressive stress is low.

  As described above, the water-proof sealing material of the present invention has high water-stopping properties even when the compressive stress is low, and deformation work when the water-proof sealing material is disposed in the installation portion can be easily performed.

Claims (4)

A waterproofing sealing material comprising a rubber component containing an ethylene / α-olefin / non-conjugated diene copolymer rubber, a compatibilizing agent having a hydrophilic group and a hydrophobic group, and a crosslinked foam containing a filler,
The amount of the compatibilizer is 5 to 45 parts by weight with respect to 100 parts by weight of the rubber component,
50% compressive stress (JIS K7220) is 40 to 85 kPa.   The water-proof sealing material according to claim 1, wherein the compatibilizing agent having a hydrophilic group and a hydrophobic group is a maleic anhydride-modified polyolefin resin.   The water-proof sealing material according to claim 1, wherein the filler contains both clay or carbon.   A softener is included in addition to the filler, and the amount of the filler and the softener is 70 to 250 parts by weight with respect to 100 parts by weight of the rubber component, and the filler and the softener are 65 parts by weight. It is contained in the ratio of: 35-50: 40, The water-stop sealing material as described in any one of Claim 1 to 3 characterized by the above-mentioned.

Images