JP3933017B2 - Manufacturing method of metal / rubber composite materials - Google Patents

Description

【００２５】
以上の結果から、次のようなことがいえる。
(1)各実施例では水系ゴム塗液が用いられているが、塗布型クロメート処理を施した場合(参考例1)および溶剤希釈タイプの場合(参考例2)に相当する性能が得られている。
(2)プレス加硫の場合、比較例1〜2のゴム塗液では当て板への粘着性が大であった。
(3)初期ゴバン目評価はどれも殆んど問題なかったが、LLC液浸せき試験後の評価では比較例1、2、4にはゴム剥れがみられた。
(4)200時間の耐熱暴露試験では、比較例1、2、4でゴムの脆化に伴う破壊がみられた。
(5)オーブン加硫物では、プレス加硫物と比較して製品表面粗さが粗かった。
【００２６】
実施例４
実施例３の条件を長さ1000mの接着剤焼付け処理済みの鋼板に適用し、ゴム溶液塗布-乾燥-加硫-巻取りの各工程が連続している連続ラインで実施したところ、製品機能評価結果は上記表の結果と変らなかった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a metal / rubber composite material. More specifically, the present invention relates to a method for producing a metal / rubber composite material by applying an aqueous NBR coating solution on a metal plate not subjected to coating-type chromate treatment.
[0002]
[Prior art]
Conventionally, as a sealing product such as a gasket, a metal plate coated with rubber to provide a sealing property has been used. The thickness of the rubber layer to be coated on the metal plate is about several tens to several hundreds of μm. Therefore, conventionally, a coating solution obtained by dissolving an unvulcanized rubber composition in an organic solvent is used for coating, drying and vulcanization. I was using it. However, in recent years, it has become difficult to use an organic solvent that has been used for dissolving rubber due to environmental problems and the like, and a water-based rubber coating solution is being used.
[0003]
When changing from a conventional solvent-dilution type product to a water-based rubber coating solution, it is required that the same performance as that of the conventional one is developed and that the cost is equivalent or lower. However, it is not easy for the water-based rubber coating liquid type to exhibit the same performance as the conventional solvent dilution type, and this is an obstacle to commercialization.
[0004]
Further, in order to increase the adhesion between the metal plate and the rubber, a coating type chromate treatment is performed on the surface of the metal plate. However, from the viewpoint of environmental problems and the like, the use of chromeless is also desired. In particular, when using a metal plate that has not been subjected to coating-type chromate treatment and applying a rubber coating solution of an aqueous dispersion, it is not easy to exhibit the same performance as the solvent dilution type.
[0005]
[Problems to be solved by the invention]
The object of the present invention is to produce a metal / rubber composite material by applying an aqueous NBR coating solution on a metal plate that has not been subjected to coating-type chromate treatment. , Non-tackiness, etc.).
[0006]
[Means for Solving the Problems]
An object of the present invention is to apply an adhesive on a metal plate that has not been subjected to coating-type chromate treatment, to which an aqueous latex of NBR having a bound acrylonitrile amount of 30% or more and a water of carbon black having a particle size of 5 to 300 nm. This is achieved by a method of producing a metal / rubber composite material by applying a water-based rubber coating solution containing a dispersion and drying, followed by press vulcanization at a surface pressure of 0.1 MPa or more.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
As the metal plate, a stainless steel plate, an aluminum plate, a galvanized steel plate or the like is used, and the thickness is not limited, but generally about 0.1 to 2.0 mm is used. In order to develop sufficient performance, it is preferable to use the metal plate surface after being treated with a metal phosphate (bonding), in which case the metal plate not only improves the adhesion of the coating, It will also contribute to the improvement of corrosion resistance.
[0008]
An adhesive is applied onto the metal plate prior to the formation of the rubber layer. As the adhesive, at least one of a phenol-based adhesive, a silane-based or titanate-based coupling agent is used. As the phenolic adhesive, a phenol / formaldehyde polycondensate is preferably used. Typical examples of the silane coupling agent include methoxysilanes and ethoxysilanes having a functional group such as a vinyl group, an amino group, and a mercapto group. Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, isopropyl tris (dioctylpyrophosphate) titanate, and tetraisopropylbis (dioctyl phosphite) titanate. In the adhesive containing these as a main component, a polymer component such as an elastomer, an inorganic additive such as silica, an organometallic catalyst, or the like may be added as necessary to improve the adhesive strength. Application of these adhesives onto the metal plate can be performed by any method such as dipping, spraying, or brushing, followed by baking at a predetermined temperature.
[0009]
An aqueous rubber coating solution containing an aqueous latex of NBR and an aqueous dispersion of carbon black is applied on the metal plate to which the adhesive has been applied. As NBR used in the form of aqueous latex, NBR having a bound acrylonitrile amount of 30% or more, preferably 35% or more is used. When one having an acrylonitrile bond amount of less than 30% is used, a coating film having sufficient physical properties and non-adhesiveness cannot be formed. NBR is used as an aqueous latex having a solid concentration of about 30 to 60% by weight in order to eliminate organic solvents from the viewpoint of environmental hygiene. Actually, NBR aqueous latex such as Nipol series of Nippon Zeon products 1551, 1561, 1571, 1571C, 1571E, 1571H, 1571CL, LX511, LX513, LX517A, LX551 and the like are used as they are. In some cases, other polymer latex such as acrylic rubber aqueous latex and fluororubber aqueous latex may be used in combination.
[0010]
Carbon black having a particle diameter of 5 to 300 nm, preferably 20 to 250 nm, is used as a component constituting the aqueous rubber coating solution together with these NBR aqueous latexes. If a particle size larger than this is used, sufficient reinforcing properties and non-adhesiveness cannot be secured for the coating film, whereas if a particle size smaller than this is used, handling of the dispersion becomes difficult. . Examples of the carbon black having a particle diameter in such a range include SAF, ISAF, HAF, FEF, SRF, MT grades and the like.
[0011]
Carbon black is used in a proportion of 40 to 160 parts by weight, preferably 60 to 140 parts by weight, with respect to 100 parts by weight of NBR in the aqueous latex, and gives sufficient reinforcement and non-stickiness to the formed coating film. By increasing the blending ratio of inexpensive carbon black, the cost of the product can be reduced.
[0012]
In the water-based rubber coating solution, a peroxide-based or sulfur-based vulcanizing agent used for vulcanization of NBR and other necessary compounding agents are added and used. In selecting a vulcanizing agent, vulcanization physical properties and vulcanization speed are important, and it is desirable to consider these points. From the viewpoint of vulcanization speed, a vulcanizing agent that vulcanizes in a temperature range of about 160 to 260 ° C., preferably about 180 to 230 ° C. for about 5 to 300 seconds, preferably about 10 to 200 seconds, is desirable, Examples of commercially available peroxide compounds that can realize this include Japanese oil products Perbutyl Z, Perhexa Z, Perbutyl P, Park Mill D, Perhex 25B, Perbutyl C, Perbutyl D, Park Mill P, etc. Examples of the system compound include sulfur, for example, thiuram compounds such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetramethylthiuram monosulfide, thiazole compounds such as 2-methcaptobenzothiazole, dibenzothiazyl disulfide, and dimethyldithiocarbamic acid. Zinc, zinc diethyldithiocarbamate, dibutyldithiocarbamine Dithio acid salts such as zinc. In particular, when a peroxide compound is used, the heat resistance of the coating film is improved. In addition to these vulcanizing agents and vulcanization accelerators, vulcanization accelerators that satisfy the above vulcanization conditions may be used in combination.
[0013]
The aqueous rubber coating solution containing each of the above components is applied to the metal plate by a known method such as a roll coating method, a knife coating method, a flow coating method, a die coating method, a dipping method, or a combination of these methods. Done. After coating, drying is performed at about 50 to 250 ° C. for several to several tens of minutes, and then press vulcanization is performed.
[0014]
The press vulcanization is performed by heating at about 160 to 260 ° C. for about 5 to 300 seconds under a surface pressure of 0.1 MPa or more, preferably about 0.2 to 10 MPa, and a film thickness of about 20 to A vulcanized rubber layer of 400 μm, preferably about 20 to 200 μm is formed.
[0015]
The metal / rubber composite material manufacturing method performed in this way can be applied to, for example, a long metal plate having a length of 100 m or more, and is a long adhesive-coated metal that is not subjected to coating-type chromate treatment. A series of processes, a process of applying a water-based rubber coating solution on a plate, a process of drying moisture, and a process of vulcanizing and bonding a metal plate and a coating film by a press can be performed as a continuous line system. A long metal / rubber composite material having desired physical properties, reinforcing properties, non-adhesiveness, and the like can be obtained.
[0016]
【The invention's effect】
In the method of the present invention, an organic solvent is not used as the rubber coating liquid, and the conventional organic solvent dilution type rubber coating liquid or coating type chromate-treated metal is used even though the surface treatment of the metal plate is not subjected to the coating chromate treatment. A metal / rubber composite material exhibiting the same performance as when using a plate is obtained.
[0017]
More specifically, the following effects can be obtained.
(1) By adopting the press vulcanization method as the vulcanization method, vulcanization adhesion is completed in a short time of 5 to 300 seconds depending on the vulcanization temperature.
(2) Despite the thin film thickness of about 20 to 400 μm, the surface of the product becomes smooth and the sealing performance is improved. In addition, peroxide addition that inhibits vulcanization in the atmosphere occurs. Vulcanization can also be performed in a sulfur system.
(3) Moreover, since the volatilization and dissipation of additives and the like due to heat during vulcanization can be suppressed, it is advantageous in terms of environmental hygiene.
(4) It is considered that the product function is improved without using a chromate conversion coating on the metal plate because of the press vulcanization method.
(5) Press vulcanization in a short time enables the production system to be a continuous line system, thereby reducing costs.
[0018]
The following can be said in connection with the production method being a continuous line method. Unlike the press vulcanization method for each batch, the continuous line method must be able to vulcanize for a short time when continuously vulcanizing a rubber product. It is also important to prevent the problem of sticking to the skin. If these points are not satisfied, the production speed will be slow, and it will be difficult to maintain the quality such as foreign matter will easily adhere to the product surface, resulting in an increase in cost. Since such a point is sufficiently satisfied, a continuous line system is possible.
[0019]
The metal / rubber composite material of the present invention having such characteristics can be effectively used as a sealing product for sealing liquid or gas such as a gasket.
[0020]
【Example】
Next, the present invention will be described with reference to examples.
[0021]
Examples 1-3, Reference Examples 1-2, Comparative Examples 1-4
Adhesive coated steel sheet I: A phenolic adhesive was applied by dipping on SPCC steel sheet that had been subjected to bond treatment, and the adhesive was baked at 180 ° C for 5 minutes. Adhesive coated steel sheet II: SUS steel sheet (SUS304) Silane-based adhesive (Dygussa product)
Dynasilan DAMO) was applied by dipping, dried at 60 ° C for 20 minutes, and then baked at 180 ° C for 5 minutes. Adhesive coated steel sheet III: Silane system on SUS steel sheet (SUS304) that had been subjected to coating-type chromate treatment Adhesive (Dynasilan DAMO) was applied by dipping, dried at 60 ° C for 20 minutes, and then baked at 180 ° C for 5 minutes. Rubber coating solution A: NBR aqueous latex (Nippon ZEON product Nipol 1571E; solid content 40) (Weight%) HAF grade carbon black aqueous dispersion (carbon black concentration: 30% by weight) 200 g, zinc white 10 g, sulfur vulcanizing agent aqueous dispersion (Nihon Zeon SD-1) 6g was added sequentially and stirring was continued for 60 minutes to obtain a rubber coating solution. Rubber coating solution B: NBR aqueous latex (Nippon Zeon product Nipol 1571C; solid content concentration 45% by weight) 222g MT grade carbon under stirring Aqueous dispersion of black and HAF grade carbon black (MT / HAF = 7/3, Bon black concentration: 40% by weight) 200 g, zinc white 10 g, peroxide-based vulcanizing agent (Nippon Yushi Products Perbutyl P) 8 g of water dispersion (peroxide concentration: 40% by weight) were sequentially added and stirred for 60 minutes. Rubber coating solution C: NBR aqueous latex (Nippon ZEON product Nipol LX513; solid content 45% by weight) 222 g of HAF grade carbon black in water dispersion (carbon black concentration: 30 wt%) 200 g, zinc white 10 g, and sulfur-based vulcanizing agent aqueous dispersion (SD-1) 6 g were sequentially added, and stirring was continued for 60 minutes to obtain a rubber coating solution. Rubber coating solution D: NBR aqueous latex (Nipol 1571E; solid content: 40 wt%) HAF grade carbon black water dispersion (carbon black concentration: 30 wt%) 100 g with stirring in 250 g, zinc white 10 g, sulfur vulcanizing agent water dispersion (SD-1) 6g was sequentially added and stirring was continued for 60 minutes to obtain a rubber coating solution. Rubber coating solution E: NBR polymer (Nippon Synthetic Rubber Products N) 220S) 100g, HAF grade carbon black 60g, zinc white 10g, stearic acid 1g, anti-aging agent (3C) 1g, sulfur 1g, accelerator TS-10 2.5g, kneaded with dough 525g toluene Dissolved in [0022]
Cut the steel sheets I to III, which have been subjected to the adhesive baking treatment, into a size of 200 × 200 mm, and apply the rubber coating liquids A to E on the upper surface thereof with a knife coater so that the coating thickness after drying becomes 60 μm or 100 μm. It was applied to. Next, dehydration drying was performed for 6 minutes on a hot plate heated to 80 ° C, and the dried sample was covered with a SUS304 plate, and the press was heated to 200 ° C for 2 minutes at 2 MPa. (However, although oven vulcanization was performed in Comparative Examples 3 to 4, since generation of volatile gas was remarkable at 200 ° C., oven vulcanization was performed at 180 ° C.).
[0023]
The obtained sample was measured or evaluated for the following items.
Non-adhesiveness to mold: Evaluated by ease of peeling of SUS304 plate, evaluated as non-adhesive ○, high adhesiveness as × Gobang test (adhesiveness): initial and long life coolant (Toyota Genuine LLC) After immersing in a liquid at 130 ° C for 72 hours, conduct a gobang eye tape test, with a rating of 10 to 0, initial 10 and 9 passed, and after immersion, a bending test (pass crack) Resistance): Compliant with JIS K-5400; Yes, when it is bent 180 ° after exposure to heat at initial and 130 ° C for 50 hours or 200 hours, no cracks or peeling is observed, but no peeling △ when partial cracking is observed, × when these are recognized Surface roughness (surface smoothness): Measure the surface roughness of the coating film with a surface roughness meter, roughness Ra and maximum Measure roughness Rmax [0024]
The above measurement and evaluation results are shown in the following table. In Comparative Example 3 (vulcanization time 3 minutes), no vulcanization was performed, and in Comparative Example 4 (vulcanization time 20 minutes), a large amount of malodorous gas was generated during vulcanization.

[0025]
From the above results, the following can be said.
(1) In each example, a water-based rubber coating solution is used, but performance equivalent to that of a coating type chromate treatment (Reference Example 1) and a solvent dilution type (Reference Example 2) was obtained. Yes.
(2) In the case of press vulcanization, the rubber coating liquids of Comparative Examples 1 and 2 had high adhesion to the backing plate.
(3) Although there was almost no problem in the initial evaluation of Gobang, rubber peeling was observed in Comparative Examples 1, 2, and 4 in the evaluation after the LLC immersion test.
(4) In the heat-resistant exposure test for 200 hours, in Comparative Examples 1, 2, and 4, destruction due to embrittlement of rubber was observed.
(5) The oven vulcanized product had a rough product surface roughness compared to the press vulcanized product.
[0026]
Example 4
When the conditions of Example 3 were applied to a steel plate that had been baked with an adhesive having a length of 1000 m, and each of the steps of rubber solution coating, drying, vulcanization, and winding were performed continuously, product function evaluation was performed. The results were not different from the results in the above table.

Claims (10)

A water-based rubber containing an aqueous latex of NBR with a bonded acrylonitrile content of 30% or more and a carbon black aqueous dispersion with a particle size of 5 to 300 nm. A method for producing a metal / rubber composite material comprising applying a coating liquid and drying, followed by press vulcanization at a surface pressure of 0.1 MPa or more. 2. The method for producing a metal / rubber composite material according to claim 1, wherein a metal plate which has been surface-treated with a metal phosphate is used. 2. The method for producing a metal / rubber composite material according to claim 1, wherein the adhesive is a phenol-based adhesive, a silane-based or a titanate-based coupling agent. 2. The method for producing a metal / rubber composite material according to claim 1, wherein carbon black is used in an amount of 40 to 160 parts by weight per 100 parts by weight of NBR in the aqueous latex. The method for producing a metal / rubber composite material according to claim 1, wherein a water-based rubber coating solution to which a peroxide or a sulfur-based vulcanizing agent is added is used. The method for producing a metal / rubber composite material according to claim 1, wherein the press vulcanization is performed at 160 to 260 ° C for 5 to 300 seconds. The method for producing a metal / rubber composite material according to claim 1, wherein a coating film having a thickness of 20 to 400 μm is formed. 2. The process of applying a water-based rubber coating solution on a long adhesive-coated metal plate, drying the moisture, and vulcanizing and bonding the metal plate and the coating film with a press are performed as a continuous line system. Manufacturing method for metal and rubber composites. A metal / rubber composite material produced by the method according to claim 1. 10. The metal / rubber composite material according to claim 9, which is a liquid or gas sealing product for sealing.