JP4165149B2 - Vulcanization primer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vulcanization adhesion primer. More specifically, the present invention relates to a vulcanization adhesion primer effective for forming a metal-rubber composite having excellent water-resistant adhesion under severe conditions such as in a container filled with pressurized oxygen.
[0002]
[Prior art]
Stainless steel is often used to form a composite of metal and rubber that requires resistance to water and LLC (Long Life Coolant), but a vulcanized adhesive is applied directly onto the stainless steel. When rubber is vulcanized and bonded, the resulting stainless steel-rubber composite is poor in water resistance and LLC resistance, and when these immersion tests are carried out, adhesion peeling occurs.
[0003]
As a countermeasure for this, as a pretreatment for applying a vulcanized adhesive, a coating type chromate treatment is performed on stainless steel to improve resistance to water and LLC (Japanese Patent Laid-Open No. 2000-6307). Gazette, JP-A-11-221875, etc.). However, the coating-type chromate treatment is not preferable from the viewpoint of environmental measures because it contains Cr ⁶⁺ ions.
[0004]
The present applicant has previously proposed various vulcanized adhesive compositions based on alkoxysilane (Japanese Patent Laid-Open Nos. 7-34054, 7-216309, and 8-209102, No. 9-3432, No. 9-40916, No. 9-132758, No. 10-7990, No. 10-8021, No. 11-1672, JP 2001-226642) These vulcanized adhesive compositions are particularly suitable for bonding to metal surfaces that have been previously chemically, electrochemically or physically surface treated, but when applied to untreated metal surfaces, for example Adhesion as high as that of stainless steel subjected to coating-type chromate treatment cannot be obtained.
[0005]
In addition, although a coating composition for metal using alkoxysilane has been proposed, the purpose is to protect the metal from corrosion, and it has not been used to vulcanize and bond rubber. (Kaisho 63-81176, JP 10-60377, JP 2000-230150).
[0006]
In addition, various vulcanized adhesive primeres based on phenolic resins are also commercially available, but do not exhibit sufficient adhesion and water resistance in bonding with stainless steel.
[0007]
The present applicant has also proposed a vulcanization adhesion primer based on alkoxysilane, to which an organometallic compound is added (Japanese Patent Laid-Open No. 2004-26848), and this vulcanization adhesion primer is a hot water immersion test. However, it does not necessarily exhibit sufficient water resistance under severe use environments such as water resistance in a pressurized oxygen-sealed container or energization in salt water.
[0008]
[Problems to be solved by the invention]
The object of the present invention is to form a composite of a metal such as stainless steel and rubber with a water resistance under severe use conditions such as in a pressurized oxygen sealed container without subjecting the metal to harmful coating-type chromate treatment. It is an object of the present invention to provide a vulcanization adhesion primer capable of forming a metal-rubber composite having excellent adhesion.
[0009]
[Means for Solving the Problems]
Such object of the present invention is achieved by vulcanization worn primers containing copolymerized oligomers and quaternary phosphonium salts of an amino group-containing alkoxysilane and vinyl group-containing alkoxysilane.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the amino group-containing alkoxysilane that is one component of the copolymer oligomer include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane. N-β- (aminoethyl) -γ-aminopropyltriethoxysilane and the like are used. When these amino group-containing alkoxysilanes are used as they are as one component of the adhesive composition, film formation cannot be performed well and a good adhesive cannot be provided, so copolymerization with vinyl group-containing alkoxysilanes. Used as an oligomer.
[0011]
As the vinyl group-containing alkoxysilane which is another component, for example, vinyltrimethoxysilane, vinyltriethoxysilane or the like is used. These vinyl group-containing alkoxysilanes are hardly soluble in water, become oily and separate, and cannot be mixed with other components. Moreover, since the oligomer is also hardly soluble in water and precipitates, it is used as an oligomer with an amino group-containing alkoxysilane.
[0012]
In the oligomerization reaction, 25 to 400 parts by weight, preferably 50 to 150 parts by weight of vinyl group-containing alkoxysilane and 20 to 150 parts by weight of water for hydrolysis are used with respect to 100 parts by weight of amino group-containing alkoxysilane. . When the vinyl group-containing alkoxysilane is used in a larger proportion, the compatibility with the top coat or rubber is deteriorated and the adhesiveness is lowered. On the other hand, when it is used in a smaller proportion, the water resistance is lowered. It becomes like this.
[0013]
In the oligomerization reaction, these are charged into a reactor having a distillation apparatus and a stirrer, and stirred at about 60 ° C. for about 1 hour. Thereafter, an acid such as formic acid or acetic acid is added within 1 hour to about 1 to 2 moles per mole of amino group-containing alkoxysilane. The temperature at this time is kept at about 65 ° C. The mixture is further stirred for 1 to 5 hours to allow the reaction to proceed, and at the same time, the alcohol produced by hydrolysis is distilled under reduced pressure. Distillation is terminated when only distilled water is present, and then diluted and adjusted such that the silane concentration is 30 to 80% by weight, whereby the desired copolymer oligomer is obtained. This copolymer oligomer is an oligomer having a degree soluble in an alcohol-based organic solvent such as methanol or ethanol. Moreover, what is already marketed as a copolymerization oligomer can also be used as it is.
[0014]
The use of an amino / vinyl group-containing alkoxysilane copolymer oligomer for joining a metal such as stainless steel and fluororubber has been proposed by the present applicant (WO 02/24826). Is used as a vulcanized adhesive, while in the present invention it is used as a primer for vulcanized adhesive and requires a separate vulcanized adhesive.
[0015]
As the quaternary phosphonium salts, particularly tetra -n- butyl phosphonium bromide, tetra -n- butyl phosphonium hydroxide, tetraphenyl phosphonium bromide, ethyl triphenyl phosphonium bromide, n- butyl triphenyl phosphonium bromide, benzyl Examples include triphenylphosphonium chloride, 2-carboxyethyltriphenylphosphonium bromide, methylphenylphosphonium bromide, tetra-n-butylphosnium hydrogen difluoride, tetra- n - butylphosnium hydrogen trifluoride and the like .
[0016]
These quaternary phosphonium salts may be from about 1 to 100 parts by weight per 100 parts by weight of copolymerized oligomers preferably used in a ratio of about 5 to 20 parts by weight. If the proportion used is less than this, the water resistance will be lowered, while if used in a proportion larger than this, the compatibility with the top coat and rubber will be deteriorated and the adhesiveness will be lowered. .
[0017]
The primer for vulcanization adhesion comprising the above components as essential components is generally about 0.2 to 3 weight of a mixed solvent of an alcoholic organic solvent such as methanol, ethanol or isopropanol or a ketone organic solvent such as acetone or methyl ethyl ketone and water. It is prepared and used as a solution of% concentration. The organic solvent and water are used in a mixture such that the former is about 100 to 80% by weight and the latter is about 0 to 20% by weight. When water is used in combination, the copolymer oligomer has a higher molecular weight and a strong film can be formed. In the case where stability with time of this vulcanization adhesion primer is required, it is effective to add an organic or inorganic acid.
[0018]
Further, only water can be used instead of the organic solvent. In this case, a nonionic surfactant is further added and used in order to ensure wettability with the metal.
As the nonionic surfactant, polyoxyethylene alkyl ether or the like is used as an aqueous solution having a concentration of about 0.01 to 0.1% by weight, and the vulcanized adhesive primer is about 0.2 to 3% by weight in the aqueous solution of the nonionic surfactant. It is used by dissolving or dispersing in a concentration of%.
[0019]
Such a primer for vulcanization adhesion is applied to a metal such as stainless steel, mild steel, copper, magnesium, aluminum, aluminum die-cast, etc. by dipping, spraying, brushing, roll coating or the like at room temperature. And then dried at about 100-200 ° C. for about 5-10 minutes. In general, a vulcanized adhesive according to the type of rubber combined with the metal is applied as a top coat on this vulcanized adhesion primer as a primer formed with a film thickness of about 0.1 to 10 μm. After performing the baking process, an unvulcanized rubber compound is bonded, and vulcanization at a vulcanization temperature corresponding to the type of rubber is performed under pressure as necessary. The unvulcanized rubber compound can also be coated and used as a rubber solution dispersed in an organic solvent.
[0020]
As rubber to be bonded to metal, (hydrogenated) NBR, fluoro rubber, acrylic rubber, chloroprene rubber, etc. are used as unvulcanized rubber compound after compounding vulcanizing agent, reinforcing agent and other various compounding agents. It is done. Depending on the type of unvulcanized rubber compound, it is possible to vulcanize and bond only by the primer treatment of the present invention without applying a top coat.
[0021]
As the unvulcanized NBR compound, for example, the following blending examples are shown.
(NBR formulation example)
NBR (medium-high nitrile; JSR product N237) 100 parts by weight
HAF carbon black 10 〃
SRF carbon black 40 〃
Cellulose powder 10 〃
Zinc oxide 10 〃
Stearic acid 1 〃
Microcrystalline wax 2 〃
Anti-aging agent (ODA-NS, Ouchi Emerging Chemicals) 4 〃
Plasticizer (Buyer OT product from Bayer) 5 〃
Organic peroxide (NIPPON OIL & PRODUCTS PERHEXA 25B) 6 〃
N, Nm-Phenylenedimaleimide 1 〃
[0022]
(Hydrogenated) NBR is not limited to the type of vulcanizing agent, and any sulfur vulcanizing agent such as sulfur or tetramethylthiuram monosulfide, or one that can be vulcanized or crosslinked with a peroxide cross-linking agent is optional. Used for. As the peroxycide-crosslinked unvulcanized nitrile rubber compound, for example, those shown in the above blending examples are used.
[0023]
As the fluororubber, both polyol vulcanizability and peroxide vulcanizability can be used. Examples of the unvulcanized fluororubber compound include the following blending examples.
(Fluoro rubber compounding example)
Fluoro rubber (DuPont product Viton E45) 100 parts by weight Calcium metasilicate 40 部
MT carbon black 2 〃
Magnesium oxide (Kyowa Chemical Product Magnesia # 150) 6 〃
Calcium hydroxide 3 〃
Vulcanizing agent (DuPont product curative # 30) 2 〃
Vulcanization accelerator (the company's product curative # 20) 1〃
[0024]
As the polyol vulcanizable fluoro rubber, generally vinylidene fluoride and other fluorine-containing olefins such as hexafluoropropene, pentafluoropropene, tetrafluoroethylene, trifluorochloroethylene, vinyl fluoride, perfluoro (methyl vinyl ether), etc. Copolymers with at least one kind are mentioned, and these fluororubbers are polyhydroxy such as 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) perfluoropropane, hydroquinone and the like. The polyol is vulcanized with an aromatic compound.
[0025]
Examples of the peroxide vulcanizable fluororubber include fluororubbers having iodine and / or bromine in the molecule, and these fluororubbers are added by organic peroxides generally used for peroxide vulcanization. Sulfurized (crosslinked). In this case, it is preferable to use a polyfunctional unsaturated compound represented by triallyl isocyanurate together with the organic peroxide.
[0026]
【The invention's effect】
The primer for vulcanization adhesion according to the present invention exhibits a water-resistant adhesion comparable to or better than a coating-type chromate treatment agent, particularly in severe use such as being water-resistant in pressurized oxygen sealed containers or energized in salt water. Provides metal-rubber composites that exhibit sufficient water resistance in the environment, so seal products (for example, oil seals, packings, gaskets, etc.), valves, vibration control / vibration-proof products (for example, oil seals) In addition, it can be effectively used for the surface treatment of metals such as stainless steel used in the manufacture of industrial rubber products and the like.
[0027]
【Example】
Next, the present invention will be described with reference to examples.
Reference Example Prepare a flask equipped with a stirrer, a heating jacket and a dropping funnel by charging 64 parts of γ-aminopropyltriethoxysilane (weight, the same applies hereinafter) and 20 parts of water, and adding formic acid until the pH is 4-5. And stirred for several minutes. While continuing to stir, 16 parts of vinyltriethoxysilane was gradually added dropwise using a dropping funnel. After completion of the addition, the mixture was heated to reflux at about 60 ° C. for 5 hours and cooled to room temperature to obtain a copolymer oligomer .
[0028]
Example 1
2.7 parts of copolymer oligomer obtained in Reference Example
Benzyltriphenylphosphonium chloride 0.8 part Methanol 86.5 parts Water 10.0 parts or more of each component were mixed and stirred for several minutes to prepare a primer for vulcanization adhesion.
[0029]
This primer for vulcanization adhesion was applied to a degreased SUS304 test piece, air-dried at room temperature, and then baked at 190 ° C. for 10 minutes. After cooling, the following various vulcanized adhesives A or B were applied as top coats and air-dried at room temperature, followed by baking at 150 ° C. for 10 minutes.
Topcoat A: Phenolic resin adhesive (Rohm and Haas product Sixon 715)
Topcoat B: Phenolic resin / epoxy resin adhesive
(Toyo Chemical Research Products Metallock XN-870)
[0030]
Vulcanization adhesion was performed by placing each unvulcanized rubber compound (nitrile rubber compound or fluororubber compound of the above-mentioned compounding example) on the treated specimen and applying pressure vulcanization at 180 ° C. for 6 minutes.
[0031]
Example 2
In Example 1, the same amount of methyltriphenylphosphonium bromide was used instead of benzyltriphenylphosphonium chloride .
[0032]
Example 3
In Example 1, the same amount of tetra-n-butylphosphonium hydroxide was used instead of benzyltriphenylphosphonium chloride .
[0033]
Example 4
In Example 1, a primer composed of the following components was used as a vulcanization adhesion primer.
Copolymer oligomer obtained in Reference Example 2.7 parts Tetra-n-butylphosphonium hydroxide 0.8 parts Nonionic surfactant (Kao product Emulgen 709) 0.03 parts Water 96.47 parts [0034]
With respect to the adhesion test pieces obtained in each of the above Examples, the rubber residual area ratio (%) after the water resistance test under the initial and various conditions was measured by a method according to JIS K-6256 90 ° peel test. The water resistance test was conducted for the following three methods.
Hot water immersion test: After immersing the specimen in pure water at 80 ℃ for 70, 140 or 280 hours,
Measure residual rubber area ratio (%) Hot water immersion test under pressurized oxygen: put test piece and pure water in pressurized container and seal
Enclose 0.3MPa of oxygen and soak for 24 or 48 hours at 80 ℃
After coughing, rubber residual area ratio (%) is measured. Salt water energization test: JIS Z2371 compliant; 30 ° C, 3% by weight saline solution;
Install an aluminum plate on the + pole and 1A steady current for 5 or 10 hours
After application, the residual area ratio (%) is measured.
The results obtained are shown in Table 1 below.
Table 1
Example
Measurement period 1 2 3 4
[NBR compound, topcoat A]
(Initial) 100 100 100 100
(Hot water immersion test)
After soaking for 70 hours 100 100 100 100
After immersion for 140 hours 100 100 100 100
After immersion for 280 hours 100 100 100 100
(Hot water immersion test under pressurized oxygen)
After soaking for 24 hours 100 100 100 100
90 85 95 100 after soaking for 48 hours
(Salt water energization test)
After soaking for 5 hours 100 100 100 100
90 90 95 95 after soaking for 10 hours
[Fluoro rubber compound, Top coat B
(Initial) 100 100 100 100
(Hot water immersion test)
After soaking for 70 hours 100 100 100 100
After immersion for 140 hours 100 100 100 100
After immersion for 280 hours 100 100 100 100
(Hot water immersion test under pressurized oxygen)
After soaking for 24 hours 100 100 100 100
After soaking for 48 hours 100 90 100 100
(Salt water energization test)
After soaking for 5 hours 100 100 100 100
After 95 hours of hot water immersion 95 95 95 95
[0036]
Comparative Example 1
In Example 1, benzyltriphenylphosphonium chloride was not used.
[0037]
Comparative Example 2
In Example 1, the same amount of titanium tetraacetylacetonate was used instead of benzyltriphenylphosphonium chloride .
[0038]
Comparative Example 3
In Example 1, a commercially available phenolic resin-based undercoat adhesive (Toyo Chemical Laboratory product Metaloc PA-3375) was used as a vulcanization adhesion primer.
[0039]
Comparative Example 4
In Example 1, a commercially available silane-based undercoat adhesive (Lord Far East product Chemlock AP-133) was used as a vulcanization adhesion primer.
[0040]
About the adhesion test pieces obtained in Comparative Examples 1 to 4 above, the rubber residual area ratio after the water resistance test under the initial and various conditions in the same manner as each Example by the method according to the 90 ° peel test of JIS K-6256 (%) Was measured.
[0041]
The results obtained are shown in Table 2 below.
Table 2
Comparative example
Measurement period 1 2 3 4
[NBR compound, topcoat A]
(Initial) 100 100 50 100
(Hot water immersion test)
After immersion for 70 hours 60 100 20 40
After immersion for 140 hours 30 100 0 20
After immersion for 280 hours 0 100 0 0
(Hot water immersion test under pressurized oxygen)
After soaking for 24 hours 0 90 20 30
After soaking for 48 hours 0 60 0 0
(Salt water energization test)
After soaking for 5 hours 0 80 20 40
After soaking for 10 hours 0 40 0 10
[Fluoro rubber compound, Topcoat B]
(Initial) 100 100 70 100
(Hot water immersion test)
After immersion for 70 hours 60 100 50 60
After immersion for 140 hours 30 100 0 40
After immersion for 280 hours 0 100 0 20
(Hot water immersion test under pressurized oxygen)
After soaking for 24 hours 0 80 0 40
After immersion for 48 hours 0 30 0 0
(Salt water energization test)
After soaking for 5 hours 0 80 10 50
After soaking for 10 hours 0 20 0 20

Claims (9)

Vulcanization wear primer comprising a copolymerized oligomer and quaternary phosphonium salts of an amino group-containing alkoxysilane and vinyl group-containing alkoxysilane.   The primer for vulcanization adhesion according to claim 1, wherein an oligomer obtained by copolymerizing 25 to 400 parts by weight of a vinyl group-containing alkoxysilane with 100 parts by weight of an amino group-containing alkoxysilane is used.   The primer for vulcanization adhesion according to claim 1 or 2, wherein an alcohol-based organic solvent-soluble copolymer oligomer is used.   The primer for vulcanization adhesion according to claim 1, wherein the organophosphorus compound is used in an amount of 1 to 100 parts by weight per 100 parts by weight of the copolymer oligomer.   The vulcanization adhesion primer according to claim 1 or 4, which is used by dissolving or dispersing in an alcohol-based organic solvent, an alcohol-based organic solvent-water mixed solvent, or a nonionic surfactant-containing aqueous solution.   The primer for vulcanization adhesion according to claim 1 or 5, which is used for vulcanization adhesion between metal and rubber.   The primer for vulcanization adhesion according to claim 1 or 6, which is used as a primer for a rubber vulcanization adhesive.   The primer for vulcanization adhesion according to claim 1, 6 or 7, wherein the metal is stainless steel.   The primer for vulcanization adhesion according to claim 1, 5, 6, 7 or 8, which is used for forming a metal-rubber composite which requires water resistance in a container filled with pressurized oxygen.