JP2980352B2 - Primer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a primer composition, particularly a primer composition having excellent adhesiveness under high-temperature conditions, and further having extremely high workability because the curing speed can be arbitrarily adjusted. About things.

[Conventional technology]

It is known to use primers to improve the adhesion between silicone rubber and metals or plastics.

As the primer, for example, alkoxysilane such as vinyltrimethoxysilane and tetraalkyl titanate such as tetra-n-butyl titanate are used.
However, these primers are not
There is a disadvantage that the adhesiveness cannot be maintained for a long time and the heat resistance is poor. For this reason, a method of introducing a silazane bond into a silicone polymer has been adopted for the purpose of improving the adhesion at high temperatures, but it is difficult to adjust the curing speed and the adhesion without changing the properties of the silicone rubber. There's a problem.

Furthermore, in order to solve these problems, it has been proposed to use a special polysilazane having a Si ₂ N ₂ bridge as a primer.

[Problems to be solved by the invention]

The ladder-type organopolysilazane having the Si ₂ N ₂ cross-link is relatively stable and has excellent heat resistance as compared with existing primers. However, since this polymer is manufactured using a basic catalyst and using a reaction terminator,
It is difficult to control Si ₂ N ₂ cross-linking and the amount of hydrosilyl groups, and a polymer having a certain property cannot be obtained. For this reason, the characteristics as a primer are not sufficient in that the adjustment of the curing speed is difficult and the adhesiveness is not sufficient. Therefore, an object of the present invention is to solve such a problem and to provide a primer composition having excellent adhesiveness under high-temperature conditions and having good workability capable of adjusting a curing speed.

[Means for solving the problem]

The present invention relates to a primer composition that solves the above-mentioned problem, and includes -SiH ₂ NH- or -SiH ₂ NH
It is characterized by a polysilazane having a skeleton represented by-and -SiHR ¹ NHR ^2- and further having a hydrosilyl group represented by -SiH ₃ at a terminal.

(Here, R ¹ and R ² represent a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group, an aralkyl group or an alkylsilyl group. Except when both R ¹ and R ² are hydrogen atoms.) That is, the present inventors did not decrease the adhesiveness at a high temperature,
As a result of intensive studies on primers having an appropriate curing rate, the block copolymer obtained by mixing perhydropolysilazane and polyorganosilazane and copolymerizing under a basic solvent has excellent adhesion at high temperatures. And a controlled curing speed, and completed the present invention.

Main component of the primer composition of the present invention have a basic skeleton of -SiH ₂ NH-, molecular weight 500 to 5 with -SiH ₃ group further terminal
0000 perhydropolysilazine (JP-A 60-145903, special notice
63-16325, JP-A-1-138107 and JP-A-1-138108. ) Alone or together with -SiHR ¹ NR ²
A dehydrogenation polymerization reaction of a polyorganosilazane having a molecular weight of 500 to 5000 having a basic skeleton of-in the presence of a basic solvent, or a dehydrogenation polymerization reaction in which ammonia, a primary amine, and hydrazine are further added as reactants to the reaction system Block copolymerized silazine (for example, Japanese Patent Application No. 63-32).
8472).

Here, R ¹ and R ² represent a hydrogen atom, an alkyl group which may have a substituent, a cycloalkyl group, an alkenyl group, an alkylamino group, an aryl group, an aralkyl group,
Excluded when both R ¹ and R ² are hydrogen atoms. In this case, examples of the alkyl group include methylethyl, propyl, butyl, octyl, decyl and the like, examples of the alkenyl group include vinyl, allyl, butenyl, octenyl and decenyl, and examples of the cycloalkyl group include cyclohexyl, Methylcyclohexyl and the like; alkylamino groups include methylamino and ethylamino groups; aryl groups include phenyl, tolyl, xylyl and naphthyl; aralkyl groups include benzyl group And examples of the alkylsilyl group include methylsilyl, ethylsilyl, propylsilyl, butylsilyl, octylsilyl, decylsilyl and the like. Further, the substituent may be any one which does not show reactivity to a hydrogen atom bonded to a silicon atom,
Examples thereof include an alkyl group, an aryl group, an alkoxy group, and an alkoxycarbonyl group.

Here, the reaction ratio between the inorganic polysilazane and the organic polysilazane is preferably from 100: 0 to 10:90 by weight. When the weight of organic polysilazane exceeds 90 wt%, the inorganic polysilazane Si
The effect of curing by the H ₃ group cannot be fully exhibited.

The molecular weight is 500 to 50,000, preferably 500 to 1
It is 0000. If the molecular weight is less than 500, the curing speed is slow,
If it exceeds 00, curing is too fast. The primer composition thus obtained has heat resistance and excellent adhesiveness. Of course, organic and inorganic polysilazanes can be used alone as primers, but in particular perhydropolysilazane has an active -SiH ₃ group at the end compared to Si ₂ N ₂ cross-linked polymer, so it has excellent adhesion The curing speed is fast, and organopolysilazane is relatively stable and has a slow curing speed.Adhesive strength and curing speed can be freely controlled by arbitrarily selecting the silazane block ratio. is there.

(Operation)

The primer composition obtained by the present invention has an appropriate silazane bond and an active hydrosilyl group (-Si
Because with H _3), strong adhesion to plastics with metals, and OH bonds. The curing rate can be arbitrarily controlled by the amount of -SiHR ¹ NR ^2- .

〔The invention's effect〕

Since the primer composition obtained by the present invention has a controlled curing rate, it is extremely excellent in workability,
In addition, since it has excellent adhesive strength and high heat resistance, the adhesive strength is maintained even under high temperature conditions. It is useful as a primer for various silicone rubbers that require heat resistance.

〔Example〕

Reference Example 1 A four-necked flask having an internal volume of 1 was equipped with a gas blow-in tube, a mechanical stirrer, and a dewar condenser.
After the inside of the reactor was replaced with deoxygenated dry nitrogen, 490 ml of degassed dry pyridine was placed in a four-necked flask, and cooled with ice. Then, when 51.6 g of dichlorosilane was added, a white solid adduct (SiH ₂ Cl ₂ .2C ₅ H ₅ N) was formed. The reaction mixture was ice-cooled, and while stirring, 51.0 g of purified ammonia was blown through a sodium hydroxide tube and an activated carbon tube.

After completion of the reaction, the reaction mixture was centrifuged, washed with dry pyridine, and further filtered under a nitrogen atmosphere.
850 ml were obtained. The solvent was distilled off from 5 ml of the filtrate under reduced pressure to obtain 0.102 g of a resin solid perhydropolysilazane.

The number average molecular weight of the obtained polymer was 980 as measured by GPC. When the IR (infrared absorption) spectrum (solution: dried o-xylene; concentration of perhydropolysilazane: 10.2 g /) of this polymer is examined, the wave number (cm ⁻¹ ) is 3350 (apparent absorption coefficient ε = 0.557 lg). ^-1 c
m ^-1 ) and absorption based on NH at 1175; Si at 2170 (ε = 3.14)
Absorption based on H; It was confirmed to show absorption based on SiH and SiNSi of 1020 to 820. ¹ HNMR of this polymer
(Proton nuclear magnetic resonance) spectrum (60 MHz, solvent CDCl ₃
/ Reference material TMS) measurement result, δ4.4ppm (brSiH ₃ ), δ4.8p
pm (SiH ₁ SiH ₂ ): absorption of δ1.4 ppm (brNH) was confirmed.

Reference Example 2 A four-necked flask having an internal volume of 1 was equipped with a gas blow-in tube, a mechanical stirrer, and a dewar condenser.
After the inside of the reactor was replaced with deoxygenated dry nitrogen, 300 ml of dry dichloromethane and 24.3 g (0.211 mol) of methyldichlorosilane were placed in a four-necked flask and cooled with ice. While stirring, 18.1 g (1.06 mol) of purified ammonia was blown through a sodium hydroxide tube and an activated carbon tube.

After completion of the reaction, the reaction mixture was centrifuged, washed with dry dichloromethane, and filtered under a nitrogen atmosphere. The solvent was distilled off from the filtrate under reduced pressure to obtain 8.81 g of a colorless and transparent liquid. The number average molecular weight of this product was 560 as measured by GPC. ¹ HNMR (proton nuclear magnetic resonance) spectrum (60 MHz, solvent CDCl ₃ / reference material TMS) measurement result of this polymer δ4.7 ppm (brSiH): δ1.4 ppm (brN
H): Absorption of δ 0.3 ppm (Si-CH ₃ ) was confirmed.

Example 1 0.44 gr of methylpolysilazane obtained in Reference Example 2 was added to 70 cc of a pyridine solution of perhydropolysilazane obtained in Reference Example 1 (perhydropolysilazane pure content: 4.0 gr), and purified in a pressure-resistant container having an internal volume of 300 ml. 9gr anhydrous ammonia
(0.53 mol), and the reaction was carried out while stirring at 120 ° C. for 3 hours in a closed system. After cooling to room temperature, dry o-xylene 200m
l at a pressure of 3 to 5 mmHg and a temperature of 50 ° C to remove the solvent
4.0 gr of a white powder was obtained.

This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of this copolymer was 1 according to GPC measurement.
850. The ¹ HNMR (nuclear magnetic resonance) spectrum (60
MHz, solvent CDCl ₃ / reference material TMS) measurement result δ 4.8 ppm (brSi
H), δ4.4 ppm (brkSiH ₃ ): δ1.4 ppm (brNH), δ0.3p
pm (brSiCH ₃ ) was confirmed.

This copolymerized silazane was dissolved in o-xylene and 10 wt%
After the solution was air-dried at room temperature for 10 minutes, the silicone rubber composition was coated on the iron plate to a thickness of 2 mm.
The molding was carried out under the conditions of ° C., 70 kg f / cm ² , and 10 minutes.

When the adhesiveness of this silicone rubber to an iron plate was examined, the rubber was broken at 17 kg f / 25 mm, but no peeling was observed on the bonded surface.

When this adhesive product was immersed in silicone oil at 200 ° C. for 200 hours, its adhesiveness was examined. As a result, rubber was broken at 16 kg f / 25 mm, but no peeling was observed on the adhesive surface.

Further, the composition was applied to an aluminum plate, allowed to stand at room temperature for 10 minutes and air-dried, and then the silicone rubber composition was formed on the coating film so as to have a thickness of 2 mm at 150 ° C., 70 kgf / cm ² , and 10 minutes.

When the adhesion of this silicone rubber to an aluminum plate was examined, the silicone rubber was broken at 10 kg f / 25 mm, but no peeling of the rubber was observed at the bonding surface.

Example 2 2.0 gr of methylpolysilazane obtained in Reference Example 2 was added to 50 cc of the pyridine solution of perhydropolysilazane obtained in Reference Example 1 (perhydropolysilazane pure content: 3 gr), and purified in a pressure-resistant container having an inner volume of 300 ml. 9gr anhydrous ammonia
(0.53 mol), and the reaction was carried out while stirring at 120 ° C. for 3 hours in a closed system. After cooling to room temperature, dry o-xylene 200m
l at a pressure of 3 to 5 mmHg and a temperature of 50 ° C to remove the solvent
4.5 gr of a white powder were obtained.

This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of this copolymer was 1 according to GPC measurement.
It was 650. The ¹ HNMR (nuclear magnetic resonance) spectrum (60
MHz, solvent CDCl ₃ / reference material TMS) measurement result, δ 4.8 ppm (br
SiH), δ 4.4 ppm (brkSiH ₃ ); δ 1.4 ppm (brNH);
3 ppm (brSiCH ₃ ) was confirmed.

This copolymerized silazane was dissolved in o-xylene and 10 wt%
The solution was air-dried for 15 minutes at room temperature applied to an iron plate, and the silicone rubber composition was coated on the coating film to a thickness of 2 mm.
The molding was carried out under the conditions of ° C., 70 kg f / cm ² , and 10 minutes.

When the adhesiveness of this silicone rubber to an iron plate was examined, the rubber was broken at 16 kg f / 25 mm, but no peeling was observed on the bonded surface.

When this adhesive product was immersed in silicone oil at 200 ° C. for 200 hours, its adhesiveness was examined. As a result, rubber was broken at 16 kg f / 25 mm, but no peeling was observed on the adhesive surface.

Further, the composition was applied to an aluminum plate, left to dry at room temperature for 15 minutes, and air-dried. Then, the silicone rubber composition was formed on the coating film so as to have a thickness of 2 mm at 150 ° C., 70 kgf / cm ² and 10 minutes.

When the adhesion of this silicone rubber to an aluminum plate was examined, the silicone rubber was broken at 10 kg f / 25 mm, but no peeling of the rubber was observed at the bonding surface.

Example 3 To 50 cc of the pyridine solution of perhydropolysilazane obtained in Reference Example 1 (perhydropolysilazane pure content: 2.5 gr) was added 3.75 gr of the methylpolysilazane obtained in Reference Example 2, and the mixture was purified in a pressure-resistant container having an inner volume of 300 ml. 9gr anhydrous ammonia
(0.53 mol), and the reaction was carried out while stirring at 120 ° C. for 3 hours in a closed system. After cooling to room temperature, dry o-xylene 200m
l at a pressure of 3 to 5 mmHg and a temperature of 50 ° C to remove the solvent
5.8 gr of a white powder were obtained.

This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of this copolymer was 1 according to GPC measurement.
500. The ¹ HNMR (nuclear magnetic resonance) spectrum (60
MHz, solvent CDCl ₃ / reference material TMS) measurement result, δ 4.8 ppm (br
SiH), δ 4.4 ppm (brkSiH ₃ ): δ 1.4 ppm (brNH);
3 ppm (brSiCH ₃ ) was confirmed.

This copolymerized silazane was dissolved in o-xylene and 10 wt%
The solution was air-dried at room temperature for 20 minutes after coating on an iron plate.
The molding was carried out under the conditions of ° C., 70 kg f / cm ² , and 10 minutes.

When the adhesiveness of this silicone rubber to an iron plate was examined, the rubber was broken at 16 kg f / 25 mm, but no peeling was observed on the bonded surface.

When this adhesive product was immersed in silicone oil at 200 ° C. for 200 hours, its adhesiveness was examined. As a result, rubber was broken at 16 kg f / 25 mm, but no peeling was observed on the adhesive surface.

Further, the composition was applied to an aluminum plate, allowed to stand at room temperature for 20 minutes and air-dried, and then the silicone rubber composition was formed on the coating film at 150 ° C., 70 kgf / cm ² and 10 minutes to a thickness of 2 mm.

When the adhesion of this silicone rubber to an aluminum plate was examined, the silicone rubber was broken at 10 kg f / 25 mm, but no peeling of the rubber was observed at the bonding surface.

Example 4 To 50 cc of a pyridine solution of perhydropolysilazane (perhydropolysilazane pure content: 0.5 gr) obtained in Reference Example 1, 4.5 gr of methylpolysilazane obtained in Reference Example 2 was added, and the mixture was purified in a pressure-resistant container having an inner volume of 300 ml. 9gr anhydrous ammonia
(0.53 mol), and the reaction was carried out in a closed system at 120 ° C. with stirring for 3 hours. After cooling to room temperature, dry o-xylene 20
When 0 ml was added and the solvent was removed at a pressure of 3 to 5 mmHg and a temperature of 50 ° C., 4.5 gr of a white powder was obtained.

This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of this copolymer was 1 according to GPC measurement.
It was 250. The ¹ HNMR (nuclear magnetic resonance) spectrum (60
MHz, solvent CDCl ₃ / reference material TMS) measurement result, δ 4.8 ppm (br
SiH), δ 4.4 ppm (brkSiH ₃ ); δ 1.4 ppm (brNH);
3 ppm (brSiCH ₃ ) was confirmed.

This copolymerized silazane was dissolved in o-xylene and 10 wt%
The solution was air-dried for 25 minutes at room temperature applied to an iron plate, and the silicone rubber composition was coated on the coated film to a thickness of 2 mm.
The molding was carried out under the conditions of ° C., 70 kg f / cm ² , and 10 minutes.

When the adhesiveness of this silicone rubber to an iron plate was examined, the rubber was broken at 16 kg f / 25 mm, but no peeling was observed on the bonded surface.

When this adhesive product was immersed in silicone oil at 200 ° C. for 200 hours, its adhesiveness was examined. As a result, rubber was broken at 15 kg f / 25 mm, but no peeling was observed on the adhesive surface.

Further, the composition was applied to an aluminum plate, allowed to stand at room temperature for 25 minutes and air-dried, and then the silicone rubber composition was formed on the coating film so as to have a thickness of 2 mm at 150 ° C., 70 kgf / cm ² , and 10 minutes.

When the adhesion of the silicone rubber to the aluminum plate was examined, the silicone rubber was broken at 9 kg f / 25 mm, but no peeling of the rubber was observed at the bonding surface.

Example 5 70 cc of the pyridine solution of perhydropolysilazane obtained in Reference Example 1 (perhydropolysilazane pure content: 4.00 gr) was placed in a pressure-resistant container having an inner volume of 300 ml, and purified anhydrous ammonia was added.
4.0 gr (0.235 mol) was added, and the reaction was carried out while stirring at 120 ° C. for 3 hours in a closed system.

After cooling to room temperature, 200 ml of dry o-xylene was added and the pressure was 3-5.
When the solvent was removed at a temperature of 50 ° C. and a pressure of mmHg, 3.8 gr of a white powder was obtained.

This powder was soluble in toluene, tetrahydrofuran, chloroform and other organic solvents.

The number average molecular weight of this copolymer was 1,850. Also
¹ H NMR (nuclear magnetic resonance) spectrum (60 MHz, solvent CDCl ₃ / reference material TMS) measurement result, δ 4.8 ppm (brSiH), δ 4.4 ppm
(BrkSiH ₃ ); δ1.4 ppm (brNH) was confirmed.

This ammonia-crosslinked perhydropolysilazane is converted to o
-Dissolved in xylene to make 10 wt% and applied to iron plate. After air-drying at room temperature for 5 minutes, the silicone rubber composition was formed on this coating film to a thickness of 2 mm under the conditions of 150 ° C., 70 kgf / cm ² , and 10 minutes.

When the adhesiveness of this silicone rubber to an iron plate was examined, the rubber was broken at 17 kg f / 25 mm, but no peeling was observed on the bonded surface.

When this adhesive product was immersed in silicone oil at 200 ° C. for 200 hours, its adhesiveness was examined. As a result, rubber was broken at 17 kg f / 25 mm, but no peeling was observed on the adhesive surface.

Further, the composition was applied to an aluminum plate, allowed to stand at room temperature for 5 minutes, air-dried, and then the silicone rubber composition was formed on the coating film at 150 ° C., 70 kgf / cm ² , and 10 minutes to a thickness of 2 mm.

When the adhesion of this silicone rubber to an aluminum plate was examined, the silicone rubber was broken at 12 kg f / 25 mm, but no peeling of the rubber was observed at the bonding surface.

Comparative Example Thickness of silicone rubber composition on iron plate and aluminum plate
Molding was performed at 150 ° C., 70 kg f / cm ² , and 10 minutes to a thickness of 2 mm.

When the adhesion of the silicone rubber to the respective substrates was examined, it was peeled off at 3 kg f / 25 mm on an iron plate and did not adhere at all on aluminum.

Claims (2)

(57) [Claims] 1. A primer composition comprising, as a main component, an inorganic silazane having a molecular weight of 500 to 50,000 having a basic skeleton of —SiH ₂ NH— in a molecule and having a —SiH ₃ group at a terminal. 2. In the molecule, -SiH ₂ NH- and -SiHR ¹ NR ^2- (wherein R ¹ and R ² are a hydrogen atom, a substituted alkyl group, an alkenyl group, a cycloalkyl group, an alkylamino group, an aryl group , an aralkyl group, an alkylsilyl group, or show these substituents, R ^1, at least one way of R ² has the basic skeleton of the non-hydrogen.), molecular weight 500 having terminal to -SiH ₃ group A primer composition comprising as a main component up to 50,000 block copolymerized silazanes.