JPH0742435B2 - Primer composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a primer composition useful as an undercoating agent for adhering coating materials such as paints and coating agents, especially fluororubber-based paints, onto silicone rubber moldings. Regarding

As is well known, since silicone rubber has a low energy surface, it is essentially a material that is difficult to adhere to, and paints, coating agents, etc. are applied to the surface. In this case, it has a drawback that it is difficult to obtain good adhesiveness.

Therefore, as a means for improving the adhesiveness of such silicone rubber, various primer compositions have been proposed as an undercoating agent before coating a coating material or coating agent on the silicone rubber. For the purpose of improvement, JP-A-60-67541 discloses an undercoating agent containing an acrylic resin as a main component, and JP-A-60-6754.
Japanese Unexamined Patent Publication No. 2 (1994) proposes an undercoating agent containing an epoxy-modified silicone resin as a main component.

However, although these undercoating agents have some effect on the coating of the fluororubber-based paint on the silicone rubber surface, which has been difficult to bond, the effect is not sufficient, and the adhesion after repeated fatigue is not sufficient. In addition to being poor in properties, there is a problem that it does not exhibit any effect as an undercoating agent, especially for low hardness silicone rubber.

Therefore, development of a more effective primer composition as an undercoat is desired.

The present invention has been made in view of the above circumstances, and a coating material such as a coating material and a coating agent, particularly a fluororubber coating material, can be adhered to the surface of a silicone rubber molded body with good adhesiveness, and an undercoat agent The present invention aims to provide a primer composition suitable as.

Means and Actions for Solving the Problem As a result of intensive studies for achieving the above-mentioned object, the present inventor has (A) the following general formula (I) (However, in the formula, R ¹ is a monovalent hydrocarbon group having 1 to 12 carbon atoms, X is a hydrogen atom or a methyl group.) One or more components selected from acrylates and methacrylates 40 to 40 95% by weight and the following general formulas (II) and (III) (However, in the formula, R ² is a divalent hydrocarbon group having 1 to 11 carbon atoms, which may contain an ether bond in the middle, and R ³ is 1 to 1 having 4 carbon atoms.
It is a valent hydrocarbon group, X is a hydrogen atom or a methyl group, and Y is an oxygen atom, a sulfur atom or an NH group. Further, n is 1, 2 or 3. ) A radical copolymerization of 5 to 40% by weight of one or more components selected from the compounds represented by: and 0 to 30% by weight of a compound having a vinylic unsaturated bond copolymerizable with the above components. 3 to 40 parts by weight of the radical copolymer in 100 parts by weight of the composition
Parts by weight, and (B) the following general formula (IV) (However, in the formula, R ⁴ is a monovalent hydrocarbon group having 1 to 10 carbon atoms, or (R ² and X have the same meanings as above) and m is
It is 1, 2 or 3. ) In combination with an organosilane compound selected from organopropenoxysilane and aminoalkylalkoxysilane in a proportion of 1 to 20 parts by weight in 100 parts by weight of the composition,
When these components (A) and (B) are dissolved in a solvent and a primer is applied to a silicone rubber molded product, and a coating material layer such as a paint or a coating agent is formed on the silicone rubber molded product, these coating material layers are silicone rubber. It has excellent adhesiveness to the molded product, and even when using a fluororubber-based paint that has poor adhesiveness to the silicone rubber molded product, it has excellent adhesiveness, and even if the silicone rubber molded product has a low hardness. The present invention has been completed based on the finding that, in addition to providing good adhesiveness, the adhesiveness after repeated fatigue is also excellent.

Therefore, the present invention provides a primer composition containing the component (A), the component (B), and a solvent.

Hereinafter, the present invention will be described in more detail.

The radical copolymer of the first essential component [(A) component] of the present invention is (A) the following general formula (I) (However, in the formula, R ¹ is a monovalent hydrocarbon group having 1 to 12 carbon atoms, X is a hydrogen atom or a methyl group.) One or more components selected from acrylates and methacrylates 40 to 40 95% by weight and the following general formulas (II) and (III) (However, in the formula, R ² is a divalent hydrocarbon group having 1 to 11 carbon atoms, which may contain an ether bond in the middle, and R ³ is 1 to 1 having 4 carbon atoms.
It is a valent hydrocarbon group, X is a hydrogen atom or a methyl group, and Y is an oxygen atom, a sulfur atom or an NH group. Further, n is 1, 2 or 3. ) A radical copolymerization of 5 to 40% by weight of one or more components selected from the compounds represented by: and 0 to 30% by weight of a compound having a vinylic unsaturated bond copolymerizable with the above components. It is a thing.

Here, R ¹ in the formula (I) has 1 to 12 carbon atoms as described above.
A monovalent hydrocarbon group of, for example, a methyl group, an ethyl group,
Examples thereof include alkyl groups such as propyl group.

Specific examples of the methacrylate and acrylate represented by the above formula (I) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, decyl methacrylate, dodecyl methacrylate, Examples thereof include cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, betyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, decyl acrylate and dodecyl acrylate.

Further, the methacrylate or acrylate of the formula (I) is
The film forming property of the composition of the present invention is essential for maintaining good film-forming property and drying property. The amount of this methacrylate or acrylate used is 10% by weight of the total composition of the radical copolymer.
It is necessary to be 40 to 95% with respect to 0% (% by weight, the same applies hereinafter), and particularly preferably 45 to 90%.
If it is less than 40%, the film-forming property and dryness of the film will be poor, and the appearance will be poor such as wrinkles on the top fluororubber coating film. If it exceeds 95%, it will necessarily contribute to the adhesion. Since the composition ratio of the monomer component is reduced, the adhesiveness is reduced.

Next, in the compounds represented by the above formulas (II) and (III), the substituent R ² is a divalent hydrocarbon group having 1 to 11 carbon atoms, which has an ether bond on the way, that is, is interrupted by an oxygen atom. , --CH _2- , --CH ₂ CH ₂ CH _2- , --CH ₂ CH ₂ CH ₂ CH _2- , −CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ −, −CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ −, −CH ₂ CH ₂ CH ₂ −O− Examples include groups such as CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ O—CH ₂ CH ₂ OCH ₂ CH ₂ —, and the like. R ³ is a monovalent carbon-hydrogen group having 1 to 4 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group.

Specific examples of such compounds of the formulas (II) and (III) include the following compounds.

Further, the compounds of the formulas (II) and (III) are essential for improving the adhesiveness of the coating film of the composition and imparting crosslinkability to the coating film, and the amount thereof is 100% of the total composition of the radical copolymer. % Is required to be 5-40%, but especially 5-30
% Is preferable. If the blending amount is less than 5%, the adhesiveness will be poor, and if it exceeds 40%, the adhesiveness will no longer be improved, and conversely the film-forming property will be reduced.

Furthermore, as the monomer component of the radical copolymer, in addition to the above two components, a methacrylate or acrylate of the formula (I) and a compound having a vinylic unsaturated bond copolymerizable with the compounds of the formulas (II) and (III) are used. One type or two or more types can be used and copolymerized. Examples of the compound having a vinylic unsaturated bond include styrene, vinyl acetate, vinyl propionate, vinyl caproate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, Examples thereof include acrylonitrile and butadiene.

The amount of the vinyl unsaturated bond-containing compound used is 0 to 30% based on 100% of the total composition of the radical copolymer.

The radical copolymer of the first essential component of the present invention can be easily obtained by radically copolymerizing the above monomer component.

In this case, as the polymerization method, any of bulk polymerization, emulsion polymerization, suspension polymerization, solution polymerization and the like can be applied, but since the final composition is a solvent diluent, it is possible to obtain a solvent diluent as it is. Possible solution polymerization processes are advantageous. Examples of the solvent used in the solution polymerization method include aromatic hydrocarbons such as benzene, toluene and xylene, saturated hydrocarbons such as n-hexane, n-heptane and cyclohexane,
Examples thereof include esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone, methyl isobutyl ketone and dibutyl ketone, alcohols such as isopropanol and n-butanol, and one or more of them may be used. it can.

Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobisisovaleronitrile, benzoyl peroxide, perbutyl benzoate, dicumyl peroxide, t-butyl hydroperoxide. Oxide or the like is used. The amount of the polymerization initiator used is
The range of 0.05 to 5% is preferable with respect to the total composition of the radical copolymer.

The compounding amount of the first essential component [(A) component] is 10
It is necessary to be 3 to 40 parts in 0 parts (parts by weight, the same applies hereinafter). If the amount of component (A) is less than 3 parts, the film-forming property will be poor, and as a result, the adhesive strength will be low, and if it is more than 40 parts, the film-forming property will be good, but (A) relative to component (B) Since the amount of the components becomes relatively large, the adhesive strength becomes small.

The second essential component [component (B)] of the composition of the present invention is the following general formula (IV) (In the formula, R ⁴ is a saturated or unsaturated monovalent hydrocarbon group having 1 to 10 carbon atoms, and m is 1, 2 or 3.) Organopropenoxysilane and aminoalkylalkoxysilane It is an organosilane compound selected from

Here, R ⁴ in the formula (IV) is a monovalent hydrocarbon group having 1 to 10 carbon atoms, (However, R ² and X are the same as the above.).

Specifically as the organopropenoxysilane represented by the formula (IV), Are exemplified.

The aminoalkylalkoxysilane is not particularly limited as long as it is an alkoxysilane having at least one primary or secondary amino group in one molecule, and examples thereof include the following compounds.

(CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , (C ₂ H ₅ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ ,, (CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ NHCH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OC
H ₃ ) ₃ , The above-mentioned organosilane compound is involved in the adhesiveness of the primer composition, and one or more kinds of the above-mentioned organopropenoxysilane and aminoalkylalkoxysilane of the formula (IV) are used. The blending amount is required to be 1 to 20 parts with respect to the total composition of 100 parts of the composition, and particularly preferably 2 to 10 parts. If the blending amount is less than 1 part, the adhesiveness of the composition will be insufficient, and if it exceeds 20 parts, the adhesiveness will no longer be improved and the film-forming property will be deteriorated.

The solvent, which is the third essential component of the composition of the present invention, is capable of dissolving the radical copolymer of the first essential component and the organosilane compound of the second essential component, does not cause a chemical change, and has a suitable amount. There is no particular limitation as long as it is volatile, and various solvents can be used. Specific examples of the solvent include aromatic hydrocarbons such as benzene, toluene and xylene, saturated hydrocarbons such as n-hexane, n-heptane and cyclohexane, esters such as ethyl acetate and butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, Ketones such as dibutyl ketone and cyclohexanone,
One or more alcohols such as isopropanol and n-butanol are preferably used.

The amount of the solvent used is 40 per 100 parts of the total composition.
~ 96 parts are preferred.

Further, in the present invention, optional components other than the above first to third essential components can be added as required, and for example, dyes, pigments, fillers, antistatic agents, curing catalysts, heat stabilizers, etc. should be added. You can

The primer composition of the present invention, the first and second essential components,
Further, it can be produced by dissolving an optional component in the solvent of the third essential component, and is applied by coating it on the surface of the silicone rubber molded body and volatilizing the solvent, whereby the molded body surface can be used. Is suitable for adhesion and wettability of paints, coating agents, etc., and coating materials such as paints, coating agents, etc., especially fluororubber-based paints, can be favorably adhered to the silicone rubber molded body.

Here, the primer composition can be applied to the surface of the silicone rubber molded body by any method such as spray coating, brush coating, flow coating, and dip coating. After coating, it may be left at room temperature to evaporate the solvent.
The heat treatment in the temperature range of ~ 150 ° C for 5 minutes to 2 hours promotes the evaporation of the solvent and the crosslinking of the film,
The adhesiveness can be further improved.

Further, there is no particular limitation on the type of silicone rubber to be the adherend of the primer composition of the present invention, for example, thermosetting silicone rubber addition reaction by peroxide crosslinking or room temperature or heat curing silicone rubber by condensation reaction, ultraviolet light or Any type of silicone rubber such as electron beam curable silicone rubber can be applied.

Examples of the material to be coated on the surface of the silicone rubber molded article coated with the primer composition of the present invention include fluororubber paint, fluororesin, acrylic resin, epoxy resin, polyester resin, polyamide resin, phenol resin, polyurethane. Resins, paints based on resins such as polyphenylene sulfide resin, various coating agents and the like can be mentioned. In addition to these, the composition of the present invention exerts excellent effects on various coating materials. Very effective for paints.

EFFECTS OF THE INVENTION As described above, the primer composition of the present invention has a high effect of adhering a coating material, a coating agent, etc. on the surface of a silicone rubber molded article, and also has an excellent adhesion level after repeated fatigue, and therefore is particularly fluorine-containing. It is effective in improving the adhesiveness of rubber-based paints and is also effective for low hardness silicone rubber moldings. Therefore, the composition of the present invention is useful as an undercoating agent for adhering a paint, coating agent, etc. onto a silicone rubber molded article, and in particular, a fluororubber-based coating material is applied onto a silicone rubber roll coated with the primer composition of the present invention. The coated coating roll is useful as a toner non-fusing roll for electrophotography.

Next, a synthetic example of a radical copolymer will be shown as a reference example.

[Reference Example 1] 180 g of toluene and acetic acid i in a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas introducing tube.
180 g of -butyl was charged, nitrogen gas was bubbled, and the mixture was heated in an oil bath with stirring and heated to 90 ° C. 126 g of methyl methacrylate, 108 g of butyl methacrylate, 36 g of glycidyl methacrylate, 54 g of 3-methacryloxypropyltrimethoxysilane, 36 g of vinyl acetate and 1.4 g of benzoyl peroxide were added dropwise over 1 hour through the dropping funnel. It was aged at a temperature of 90 to 100 ° C. for 2 hours under aeration of nitrogen. Next, 1.4 g of benzoyl peroxide was added,
Aged at a temperature of 90 to 100 ° C. for 3 hours. After aging, acetic acid i
-Butyl 1680 g was added and mixed to obtain a solution of a radical copolymer containing 15% by weight of the active ingredient.

The viscosity of the obtained radical copolymer solution is 12.5cs at 25 ° C, and the polymer gel permeation chromatography (GPC)
As a result, the polystyrene reduced weight average molecular weight was 16,000.

[Reference Example 2] 150 g of i-butyl acetate in a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas introducing tube,
150 g of isopropanol was charged, nitrogen gas was aerated, and the temperature was raised to 290 ° C. in an oil bath with stirring. In this, ethyl acrylate 120 ℃, 2-ethylhexyl acrylate 45g, butyl methacrylate 45g, glycidyl methacrylate 30
g, 2-hydroxyethyl methacrylate 60 g, and benzoyl peroxide 1.2 g were added dropwise through the dropping funnel over 1 hour, and the temperature was maintained at 90 to 10 under nitrogen gas bubbling.
Aged at 0 ° C. for 2 hours. Next, benzoyl peroxide
1.2 g was added and the mixture was aged at a temperature of 90 to 100 ° C. for 3 hours. After completion of aging, 1400 g of i-butyl acetate was added and mixed to prepare active ingredient 1
A 5% radical copolymer solution was obtained.

The viscosity of the obtained radical copolymer solution was 43.5 cs at 25 ° C., and the polystyrene-equivalent weight average molecular weight of the polymer by GPC was 11,000.

[Reference Example 3] 450 g of i-butyl acetate was placed in a glass reactor equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas introducing tube.
150 g of isopropanol was charged, nitrogen gas was aerated, and the temperature was raised to 90 ° C. in an oil bath with stirring. A mixture of 140 g of methyl methacrylate, 120 g of ethyl acrylate, 40 g of glycidyl methacrylate, 60 g of 3-methacryloxypropyltrimethoxysilane, 20 g of vinyl acetate and 1.6 g of benzoyl peroxide was added dropwise through the dropping funnel over 1 hour, and nitrogen gas was further added. It was aged for 2 hours at a temperature of 90 to 100 ° C under aeration. Next, 1.6 g of benzoyl peroxide was added, and the mixture was aged at a temperature of 90 to 100 ° C. for 3 hours. After aging, acetic acid i-
1550 g of butyl was added and mixed to obtain a radical copolymer solution containing 15% of the active ingredient.

The viscosity of the obtained radical copolymer solution was 16.4 cs at 25 ° C, and the polystyrene-equivalent weight average molecular weight of the polymer by GPC was 12000.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 9 and Comparative Examples 1 to 4] Based on the radical copolymers obtained in Reference Examples 1 to 3, an organosilane compound was blended to prepare a primer composition having a composition shown in Table 1.

Next, the second molded with a thickness of 30mm around the aluminum core material.
The surfaces of the two types of base silicone rubber rolls shown in the table were polished, followed by solvent degreasing and cleaning, and then a primer composition having the composition shown in Table 1 was spray-coated and air-dried at room temperature for 1 hour. Next, a fluororubber coating (Daikin Industries, Ltd., Daiel Latex GLS-213A / B) was spray-coated on the primer coating film, and air dried at room temperature for 1 hour.
After holding it in a hot air circulation dryer at 150 ° C for 30 minutes,
Finally, the temperature inside the dryer was raised from 150 ° C. to 280 ° C. over 1 hour to obtain a silicone rubber roll whose surface was coated with a fluororubber paint.

With respect to the obtained silicone rubber roll material, the peel strength between the silicone rubber and the fluororubber coating film was measured by a tensile tester (manufactured by Shimadzu Corporation, Autograph DSC-500), and the appearance of the coating film and the electrophotographic fixing roll were measured. Built in 1
The appearance was observed after printing was performed ten thousand times.

The results are also shown in Table 2.

From the results shown in Table 2, it was confirmed that the primer composition of the present invention is excellent in the effect of improving the adhesiveness between the base silicone rubber and the fluororubber coating and is effective as a toner non-fusing roll for electrophotography. It was

Claims (1)

[Claims] 1. (A) The following general formula (I): (However, in the formula, R ¹ is a monovalent hydrocarbon group having 1 to 12 carbon atoms, X is a hydrogen atom or a methyl group.) One or more components selected from acrylates and methacrylates 40 to 40 95% by weight and the following general formulas (II) and (III) (However, in the formula, R ² is a divalent hydrocarbon group having 1 to 11 carbon atoms, which may contain an ether bond in the middle, and R ³ is 1 to 1 having 4 carbon atoms.
It is a valent hydrocarbon group, X is a hydrogen atom or a methyl group, and Y is an oxygen atom, a sulfur atom or an NH group. Further, n is 1, 2 or 3. ) A radical copolymerization of 5 to 40% by weight of one or more components selected from the compounds represented by: and 0 to 30% by weight of a compound having a vinylic unsaturated bond copolymerizable with the above two components 3 to 40 parts by weight of the radical copolymer in 100 parts by weight of the composition
Parts by weight, and (B) the following general formula (IV) (However, in the formula, R ⁴ is a monovalent hydrocarbon group having 1 to 10 carbon atoms, or (R ² and X have the same meanings as above) and m is
It is 1, 2 or 3. ) 1 to 20 parts by weight per 100 parts by weight of an organosilane compound selected from organopropenoxysilane and aminoalkylalkoxysilane, and (C) a solvent, and a primer composition. object.