JP3557693B2 - Manufacturing method of gasket material - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for producing a gasket material . More specifically, the present invention relates to a method for producing a gasket material used for a cylinder head gasket and the like.
[0002]
[Prior art]
Conventionally used gasket materials have an adhesive layer made of a thermosetting resin, a vulcanized material layer of a rubber compound and an anti-adhesion layer sequentially formed on both surfaces or one surface of a metal plate such as a steel plate, generally on both surfaces. Although it has a structure, under severe operating conditions such as cylinder head gasket, combustion gas blow-through in the bore due to settling of the vulcanized rubber layer can be seen, and due to long life coolant, which is a coolant for automobile engines Defects such as a risk of peeling of the rubber layer due to a decrease in adhesiveness and a risk of causing clogging of a fluid system due to the peeled rubber pieces being mixed into the sealing liquid are observed.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to effectively use a cylinder head gasket or the like without providing a vulcanized rubber sole layer, in order to prevent various troubles caused by a vulcanized rubber sole layer forming a seal layer of a gasket material. It is an object of the present invention to provide a method for producing a gasket material.
[0004]
[Means for Solving the Problems]
Such object of the present invention, on both sides or one side of a metal plate, containing carbon black, sufficiently rubber particles of a rubber compound dispersion until the extent of producing the microgel 50 mu m or less in size at a grain gauge kneading After coating a mixture of a dispersion of the obtained NBR compound or fluororubber compound and a thermosetting resin solution that is a phenol resin, a phenol-cresol resin or an epoxy resin, and heating and co-crosslinking the dried coating film, This is achieved by forming an anti-adhesion layer made of a non-adhesive substance and manufacturing a gasket material .
[0006]
Examples of the metal plate include an iron plate, a stainless steel plate, a carbon steel plate, an alloy steel plate, a copper plate, a copper alloy plate, an aluminum plate, an aluminum alloy plate, and the like, which are generally used for this type of application. Those having a diameter of about 1 to 1.6 mm are used after being subjected to a degreasing treatment, a roughening treatment and a chemical conversion treatment. A co-crosslinked layer of a mixture of a rubber compound and a thermosetting resin is provided on both sides or one side, generally both sides of these metal plates.
[0007]
As the rubber compound, an NBR compound containing carbon black or a fluororubber compound is used. Carbon black is used in a ratio of about 10 to 90 parts by weight, preferably about 50 to 80 parts by weight, per 100 parts by weight of the rubber component, which is a furnace black or thermal black so that a microgel is formed during kneading. Is preferred. In the rubber compound, generally used compounding agents such as a processing aid, a vulcanization accelerator, a vulcanizing agent and the like are appropriately compounded and used in addition to carbon black.
[0008]
NBR and fluororubber are generally used as an organic binder for forming a seal layer of a gasket, and also have a co-crosslinking property with a thermosetting resin. Used.
[0009]
As the thermosetting resin which is co-crosslinked with such a rubber compound, a resin having adhesion and adhesion to a metal plate which is a phenol resin, a phenol / cresol resin or an epoxy resin is used , and among these, NBR is used. Preferably, a phenol resin is used, and an epoxy resin is used for fluorine rubber.
[0010]
The ratio of the rubber compound and the thermosetting resin is about 30 to 95% by weight, preferably about 50 to 70% by weight, and the latter is about 70 to 5% by weight, preferably about 50 to 30% by weight. Respectively. If the proportion of the thermosetting resin is less than this, the effect of the combined use is not exhibited, while if it is used in a proportion greater than that, the elasticity required as a seal layer of the gasket becomes poor, and the compression and Not only is the point of restorability unsatisfactory, but also the sealability is deteriorated due to poor followability to the mating surface, and the workability is also reduced, such as cracking during bead processing. .
[0011]
Preparation of a mixture of a rubber compound and a thermosetting resin to be co-crosslinked is performed as follows . After sufficiently kneading the rubber compound with a kneader until a microgel is formed, the rubber compound is dissolved and dispersed in a mixed solvent such as methyl ethyl ketone or a mixture thereof such as xylene and toluene, and a rubber compound dispersion having a solid concentration of about 20 to 30% by weight. Is prepared. In this state, the size of the rubber particles is controlled to 50 μm or less by a particle gauge.
[0012]
This rubber compound dispersion is prepared by dissolving a thermosetting resin in a mixed solvent of methyl ethyl ketone or an alcohol or ethyl acetate containing at least 50% by weight of the thermosetting resin and having a solid content of about 40 to 60% by weight. During the addition, the mixture is gradually added with stirring, and after the addition is completed, the mixture is further stirred for about 1 hour. The type and the mixing ratio of the solvent used here are not particularly limited as long as the rubber component and the thermosetting resin component do not agglomerate and settle, respectively, as long as the coating film obtained therefrom can be obtained smoothly and uniformly.
[0013]
The rubber compound is not particularly kneaded, but it is also commonly used to prepare a rubber compound dispersion by adding each component appropriately in a solvent, dissolving and dispersing the rubber compound, but using this, thermosetting is performed. When a mixture solution with a thermosetting resin solution is prepared, the rubber component and the thermosetting resin component are mixed in a molecular order, so that a decrease in the function of the thermosetting resin as an adhesive cannot be avoided.
[0014]
The mixture solution of the rubber compound and the thermosetting resin is adjusted so that the total solid content concentration is about 5 to 30% by weight, preferably about 10 to 20% by weight in relation to the dry film thickness. The coating is performed on the metal plate surface by a coating means such as a roll coater or a knife coater. The coating film thickness can be reduced to about 5 μm as a dry film thickness, which is much lower than the conventional soft metal gasket limit of about 15 μm. Even in such a case, it is indispensable as a gasket material. The sagging property, which is the property of, is not impaired.
[0015]
Co-crosslinking of the mixture is carried out by heating the dried coating film on the metal plate surface to the vulcanization temperature of NBR or fluororubber. Thereafter, an anti-adhesion layer made of a non-adhesive substance such as wax using a thermoplastic resin such as graphite, wax or an acrylic resin, a vinyl chloride resin or a vinyl acetate resin as a binder is formed on the co-crosslinked material layer.
[0016]
[Action]
And [Effect of the invention]
Japanese Utility Model Laid-Open Publication No. Sho 62-104,068 discloses a cylinder head gasket in which an NBR layer and an adhesive surface layer made of an NBR-epoxy resin or a phenol resin mixture are sequentially formed on both surfaces of a metal plate. In this cylinder head gasket, the NBR layer, which is a single layer of vulcanized rubber, forms a seal layer, and the NBR-thermosetting resin mixture layer is formed on the surface layer as an adhesive layer.
[0017]
On the other hand, in the present invention, a mixture of NBR or a fluoro rubber and a thermosetting resin is co-crosslinked to form a seal layer as a mixture co-crosslinked material layer which is not a vulcanized rubber single layer. In addition, since an anti-adhesion layer is further formed on the mixture co-crosslinked material layer, although the NBR-thermosetting resin mixture layer is formed, although the commonality with the above prior art is seen, It can be said that the gasket material is completely different from the overall structure.
[0018]
Moreover, in the gasket material of the present invention in which such a mixture co-crosslinked material layer is used as a seal layer, the set of the gasket caused by the set of the vulcanized rubber alone seal layer is reduced, and the film of the seal layer is reduced. Although the thickness is generally about 15 to 50 μm, preferably about 15 to 25 μm, the thickness can be reduced to about 5 μm. For example, a gasket material having a mixture co-crosslinked layer having a thickness of 7 to 8 μm is formed. When the settling property was evaluated by the stress relaxation rate, the current setting of about 13% was improved to 7.0% (n = 3), and the use of a thermosetting resin further reduced the adhesiveness. Since no decrease is observed, effects such as no peeling of the seal layer are observed.
[0019]
The gasket material of the present invention having such an effect can be effectively processed as a cylinder head gasket, a long life coolant contact portion gasket, etc. after being processed into a predetermined shape.
[0020]
【Example】
Next, the present invention will be described with reference to examples.
[0021]
Example NBR (Perbunan 2807NS manufactured by Bayer AG) 100 parts by weight FEF carbon black (Tokai Carbon Product Seast SO) 50５０
Clay (Dixie Clay manufactured by Vanderbilt) 50
Plasticizer (DOP) 8 〃
Stearic acid 2 〃
Zinc oxide 10 〃
Anti-aging agent (Ouchi Emerging Chemicals Nocrack 810-NA) 1
Vulcanization accelerator (Ouchi Emerging Chemicals Noxeller TBT) 2
〃 (Ouchi Emerging Chemical Product Noxeller CZ) 2 〃
Sulfur 0.5 〃
The NBR compound was prepared by kneading the above-mentioned components in a kneading-type kneader (a general kneader type), kneading the NBR and various compounding agents together, and further adding 10 minutes more.
[0022]
The prepared NBR compound was dissolved and dispersed in a mixed solvent of methyl ethyl ketone-toluene (volume ratio of 4: 5) at a solid concentration of 25%. The size of the rubber particles in this dispersion was 25 μm or less as measured by a particle gauge.
[0023]
This NBR compound dispersion and a phenolic resin (an equal mixture of cresol novolak-type phenolic resin and cresol resol-type phenolic resin) dissolved in methyl ethyl ketone at a solid concentration of 50% were mixed at room temperature with various weight ratios. The mixture was mixed and further diluted with methyl ethyl ketone to prepare mixed solutions having various solid contents.
Mixture solution NBR compound / phenol resin ( weight ratio ) Solid content concentration ( % by weight )
A 7: 3 10
B 7: 3 15
C 6: 415
D 5: 5 15
E 5: 5 20
F 4: 6 7.5
[0024]
A steel plate (SUS 301) obtained by subjecting these mixed solutions to degreasing, surface roughening and chemical conversion treatments
To 2), coating was carried out using a dipping method, and after drying, left in an oven at 190 ° C. for 5 minutes for co-crosslinking. The steel sheet on which the mixture co-crosslinked layer was formed was immersed in a 50% by weight wax-containing urethane resin toluene solution, and left in an oven at 185 ° C. for 90 seconds to form an anti-adhesion layer.
Mixture co-crosslinked material layer thickness ( μm )
A16
B 21
C19
D16
E23
F7
[0025]
Each of the obtained gasket materials was tested for the following items, and satisfactory results were obtained with any of the gasket materials.
Heat aging test (70 hours in air at 150 ° C.):
A bending test at a diameter of 2 mm, 6 mm or 10 mm and a goban test at a width of 2 mm were performed, but no rubber peeling was observed.
Compression extrusion test (in air at 150 ° C. for 5 hours, surface pressure of 1, 2 or 3 tons / cm ² by bolt axial force):
No protrusion was observed in any case.
Bead flow test (in air at 150 ° C. for 5 hours, linear pressure 800 or 1000 kg / cm by bolt axial force):
No flow or peeling of the bead rubber was observed in any case.
LLC immersion test (50% Nissan / Toyota genuine LLC, 120 ° C, 72 hours):
All were 5 (excellent) in a 1-5 point drawing evaluation score.
Stress relaxation test (150 ° C., 210 kg / cm ² , 22 hours):
Mixture stress relaxation rate (% ; n = 3)
A 11.0
B 13.8
C 10.8
D 13.7
E 13.8
F 7.0

Claims (2)

On both sides or one side of a metal plate, containing carbon black, NBR compound or fluorine rubber rubber particles are sufficiently kneaded until a degree that is generated by the microgel 50 mu m or less in size with a grain gauge rubber compound dispersion A mixture of a compound dispersion and a thermosetting resin solution that is a phenolic resin, a phenol-cresol resin or an epoxy resin is coated, the dried coating film is heated and co-crosslinked, and then an adhesive made of a non-tacky substance is applied. A method for producing a gasket material, comprising forming a prevention layer. A gasket material produced by the method of claim 1.