JPS6348918B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a primer composition that is effective for adhering silicone rubber, particularly fluorosilicone rubber, to the surface of various substrates including metals, and that is effective in adhering the adhesion surface to engine oil resistance. The present invention relates to a primer composition that is excellent in. Conventionally, a primer is required to adhere or coat polyolefins, thermoplastic resins such as nylon, EPDM, EPR, and silicone rubber to the surfaces of glass, metal oxides, metals, etc., and various primers have been proposed and used. It's coming. Among them, as an example of a primer using an organic peroxide, vinyltris(tertiarybutylperoxy)silane is known from Japanese Patent Publication No. 49-5730. However, this method not only has the disadvantage of requiring high-temperature and long-term heat-pressing to obtain a sufficient adhesive effect, but also uses silicone rubber, especially fluorosilicone rubber, as the bonding target, and is not suitable for metals. This was insufficient for adhesion to other adherends. As a result of intensive research aimed at improving these drawbacks, the present inventors found that by using a specific organic peroxide as the main component of the primer, excellent adhesion can be achieved by heating at a lower temperature and for a shorter time or by heat-pressing. In order to complete a primer composition that is effective for adhesion between silicone rubber and adherends, particularly for adhesion between fluorosilicone rubber and adherends, and has excellent engine oil resistance on the adhesion surface. I've reached it. That is, the present invention provides: (A) 100 parts by weight of tertiary butyl peroxyallyl carbonate or tertiary butyl peroxyvinyl carbonate (B) Average unit formula

[Formula] (wherein, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group excluding R ² , (B) is a monovalent organic residue having an addition-reactive or condensation-reactive functional group, and R ³ is a monovalent organic residue having an addition-reactive or condensation-reactive functional group. alkyl group,
A group selected from an aryl group and an alkoxyalkyl group, a is 0≦a≦3, b is 0≦b≦3, c
is 0<c≦4, but 0<a+b+c≦4. ) Organosilicon compound having at least two alkoxy groups bonded to silicon atoms in one molecule 10 to 300 parts by weight (C) Organic titanates 0.1 to 50 parts by weight (D) Organic solvent Arbitrary amount The present invention relates to an adhesive primer composition comprising: Component (A) used in the present invention, tertiary butyl peroxyallyl carbonate or tertiary butyl peroxyvinyl carbonate, is an essential component for imparting adhesive properties together with component (B).
Tertiary butyl peroxyallyl carbonate or tertiary butyl peroxyallyl carbonate can be used alone or as a mixture of the two. The organosilicon compound as component (B) used in the present invention is an important component for imparting adhesive properties together with component (A), and the average unit formula is

[Formula] (In the formula, R ¹ is an alkyl group such as a methyl group, ethyl group, propyl group, or octyl group, an aryl group such as a phenyl group, or a hydrogen atom of these groups substituted with a halogen atom, a cyano group, etc.) It is a substituted or unsubstituted monovalent hydrocarbon group exemplified by R ² and does not include functional group substitution. R ² is a functional group such as a vinyl group, an allyl group, an epoxy group, a methacryloxy group, a mercapto group, or an amino group. group or N-alkylamino group, and this functional group has a methylene group, ethylene group, propylene group, phenylene group, fluoroethylene group, -
CH ₂ OCH ₂ CH ₂ CH ₂ −, −CH ₂ CH ₂ OCH ₂ CH ₂ −,
−CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ −, −(CH ₂ ) ₃
(NHCH ₂ CH ₂ )− is a monovalent organic residue having an addition-reactive or condensation-reactive functional group bonded to a silicon atom via a divalent organic group such as _{1 to 5} . R ³ is a group selected from alkyl groups such as methyl, ethyl and propyl groups, aryl groups such as phenyl, and alkoxyalkyl groups such as 2-methoxyethyl and 2-ethoxyethyl groups. a is 0≦a≦3, b is 0≦b≦3, c is 0
<c≦4, but 0<a+b+c≦4. )
Tetraalkoxysilanes, organotrialkoxysilanes, diorganodialkoxysilanes, organopolysiloxanes containing at least two alkoxy groups bonded to silicon atoms in one molecule, and partially hydrolyzed condensates thereof. In terms of adhesiveness and air-drying properties, component (B) is particularly preferable for tetrafluorocarbons having 3 to 4 alkoxyalkyl groups such as 2-methoxyethyl or 2-ethoxyethyl groups in one molecule as ^R3 . These are alkoxyalkoxysilanes, organotrialkoxysilanes, and partially hydrolyzed condensates thereof. When used, one type of component (B) is used, or two or more types are used in combination. This (B)
This component is an important component for improving adhesiveness in coexistence with component (A). The blending ratio is (A) component
10 to 300 parts by weight, preferably 30 parts by weight per 100 parts by weight
~100 parts by weight. Specific examples of component (B) include:
Vinyltrimethoxysilane, methylvinyldimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyl(methyl)dimethoxysilane, γ-methacryloxypropyltriethoxysilane, allyltrimethoxysilane, γ -Mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(3.4-epoxymicrohexyl)ethyltrimethoxysilane, γ-aminopropyltriethoxysilane, N
Examples include -β-aminoethyl-γ-aminopropyltrimethoxysilane, ethyl orthosilicate, methyl cellosolve orthosilicate, and partially hydrolyzed condensates of one or more of these silanes and silicates. The organic titanate ester as component (C) used in the present invention has the effect of improving the air-drying property of the composition of the present invention and improving the adhesion. The organic titanate esters mentioned here include not only organic titanate esters, but also partially alkoxylated titanium chelate compounds, titanium chelate compounds,
Chelate compound of titanium silicate ester,
These partially hydrolyzed condensates are included. Specific examples of component (C) include tetraisopropyl titanate, tetra-n-propyl titanate, tetrabutyl titanate, tetraamyl titanate, tetra(2-ethylhexyl) titanate, dibutyl diisopropyl titanate, triethanolamine titanate, and ethylene glycol titanate. , bis(acetylacetonato)diisopropoxytitanium, tetra(trimethylsiloxy)titanate, and partially hydrolyzed condensates thereof. These may be used alone or in combination of two or more. The amount of component (C) added is 0.1 to 50 parts by weight, preferably 1 part by weight, per 100 parts by weight of component (A).
~30 parts by weight, but the ratio of component (C) to component (B) (C)/
The best adhesion is obtained when (B) is in the range of 1/10 to 1/2. Component (D) used in the present invention is an organic solvent for dissolving the composition of the present invention, and this is selected in consideration of solubility and evaporability during application as a primer. Examples of the solvent include toluene, xylene, benzene, n-heptane, n-hexane, rubber volatile oil, and trichloroethylene, which may be used alone or as a mixed solvent of two or more thereof. However, it is not limited to this. Of these, toluene and xylene are most suitable for dissolving the above composition. In this case, the amount to be used is not particularly limited since it is advantageous to adjust the viscosity to a level suitable for coating work as a primer. The composition of the present invention can be easily obtained by simply uniformly mixing the components (A) to (C) described above, but in order to improve the physical properties of the cured film, various inorganic compounds such as fume silica, precipitate In addition to chemical silica, quartz fine powder, diatomaceous earth, calcium carbonate, red iron oxide, cerium oxide, cerium hydroxide, titanium oxide, alumina, carbon black, etc., heat resistant agents, coloring agents, etc. may be added and blended. Before use, the composition of the present invention is applied to an adherend and then air-dried for 30 minutes or more.
It is preferable to adhere silicone rubber or the like. The adherends include iron, stainless steel, steel, zinc,
Examples include metals such as nickel, brass, and phosphor bronze, plastics such as epoxy resins, polyester resins, and polyamide resins, and inorganic materials such as glass and ceramics. Silicone rubbers that are bonded to these include repeating units such as dimethylsiloxane and methyl. Vinylsiloxane, methylphenylsiloxane, phenylvinylsiloxane, 3,3,3-trifluoropropylmethylsiloxane, 3,3,
3-trifluoropropylvinylsiloxane, 3,
Heat-curable silicone rubber and addition reaction heat-curable silicone rubber whose main ingredients are a polymer represented by 3,3-trifluoropropylphenylsiloxane, a copolymer, or a mixture thereof and an organic peroxide. However, the primer composition of the present invention is particularly suitable for adhering fluorosilicone rubbers containing fluorinated hydrocarbon groups such as 3,3,3-trifluoropropyl groups, which are difficult to adhere to with conventional primers. The composition of the present invention is particularly useful as a primer, and in addition to the above, it is also useful for bonding silicone rubbers together and bonding natural or synthetic rubbers to silicone rubbers. In addition, it can be coated as a coating material, and it can also be used as an adhesion improver by adding it to various rubbers, resins, paints, etc. Next, examples of the present invention will be given. However, in each example, all parts are by weight. Example 1 Various primer compositions (each using 100 parts of toluene as an organic solvent) having the components and blending amounts as shown in Table 1 were prepared and applied to various metals such as iron, phosphor bronze, brass, nickel, and stainless steel. A thin film was applied to each plate and left to air dry at room temperature for 60 minutes. Apply 0.5% 2.5− as a crosslinking agent to the coated surface.
Fluorosilicone rubber compound (Dow Corning LS63U) with dimethyl-2.5-di(t-butylperoxy)hexane added thickness 4
Place an unvulcanized molded product of mm in size and place it under a pressure of 30Kg/ ^cm2 .
After heating at 170℃ for 10 minutes to harden it into fluorosilicone rubber and bonding it to a metal plate,
The 180 degree peel adhesive strength was determined according to the method of JIS-K-6744. The values in Table 1 are the average values of each peak (several points from the higher side) of the wavy portion of the tensile load curve. The state of adhesion upon peeling was observed with the naked eye and evaluated on the following five scales. 100% Cohesive failure...A 80% 〃 〃...B 60% 〃 〃...C Thin layer 〃 〃...D Interface peeling...E Also, the air-dry state 60 minutes after applying the primer to the metal plate The samples were examined using a touch finger, and those in a dry state were marked with an ○ mark, those with a sticky texture were marked with an x mark, and those in between were marked with a △ mark. These results are shown in Table 1.

[Table] Example 2 Example 1 of a primer composition containing several types of organic titanate compounds as shown in Table 2
Using the unvulcanized fluorosilicone rubber used in Example 1 and the metal plate, adhesive strength, adhesive condition, and air drying properties of the primer were examined in the same manner as in Example 1. Note that 100 parts of toluene was used as the organic solvent.
The results are shown in Table 2, and all showed excellent adhesion.

【table】

[Table] Manufactured by Kogyosha)
Example 3 A primer composition having the components and blending amounts as shown in Table 3 (toluene 100% as an organic solvent)
This was applied in a thin layer to a metal plate such as iron, nickel, stainless steel, or phosphor bronze, and left at room temperature for 60 minutes to air dry. Addition reaction thermosetting liquid silicone rubber (SE6706 manufactured by Toray Silicone Co., Ltd.) was poured onto the coated surface and heated for 150 min without pressure.
C. for 15 minutes to cure, and the adhesive state was examined in the same manner as in Example 1.

[Table] Example 4 Various primer compositions (using 100 parts of toluene as an organic solvent) having the components and blending amounts shown in Table 4 were prepared, and these were mixed with iron, nickel,
A thin film was applied to a metal plate such as stainless steel, brass, or phosphor bronze, left at room temperature for 60 minutes, and then air-dried. Using the same method as in Example 1, a fluorosilicone rubber compound (LS63U manufactured by Dow Corning) was cured.
They were adhered and the state of adhesion was examined.

[Table] Example 5 Various primer compositions (using 100 parts of toluene as an organic solvent) having the components and blending amounts as shown in Table 5 were prepared, and a thin film was coated on a steel plate for 60 minutes at room temperature. After leaving to air dry, fluorosilicone compound (SE1570U manufactured by Toray Silicone) was cured and bonded in the same manner as in Example 1, and the adhesion condition was examined. -30) The change in strength of the bonded part was investigated. In this case the original
◎, 60% if the adhesive strength is 80% or more
〇, if the adhesive strength is within 80% or more;
A case where the adhesive strength was 40% or more and within 60% was marked as △, and a case where the adhesive strength was 40% or less was marked as ×. In addition, those that were completely peeled off were marked as XX.

【table】

【table】

Claims (1)

[Scope of Claims] 1 (A) 100 parts by weight of tertiary butyl peroxyallyl carbonate or tertiary butyl peroxyvinyl carbonate (B) Average unit formula [ ^Formula ] (wherein R ¹ is a substituted or an unsubstituted monovalent hydrocarbon group, R ² is a monovalent organic residue having an addition-reactive or condensation-reactive functional group, R ³ is an alkyl group,
A group selected from an aryl group and an alkoxyalkyl group, a is 0≦a≦3, b is 0≦b≦3, c
is 0<c≦4, but 0<a+b+c≦4. ) Organosilicon compound having at least two alkoxy groups bonded to silicon atoms in one molecule 10 to 300 parts by weight (C) Organic titanates 0.1 to 50 parts by weight (D) Organic solvent Arbitrary amount An adhesive primer composition comprising: