JPH06157624A - Phosphonium salt and photocurable cationically polymerizable resin containing the same - Google Patents

Abstract

PURPOSE:To obtain a cationically polymerizable compsn. which is excellent in longstorage stability, quickly cures by exposure to light, does not absorb moisture, and has improved water resistance, chemical resistance, and electrical properties by compounding a cationically polymerizable compd. with a specific phosphonium salt. CONSTITUTION:A cationically polymerizable compsn. is obtd. by compounding a cationically polymerizable compd. with a phosphonium salt of the formula [wherein R<1>, R<2>, and R<3> are each (halogenated)phenyl, cyanophenyl, benzoylphenyl, or (alkyl)phenyl; R<4> and R<5> are each H or alkyl; R<6> is phenyl, naphthyl, pyrenyl, anthracenyl, or styryl ; R<7>, R<8>, and R<9> are each alkyl, alkoxy, halogen, nitro, hydroxyl, silyl(oxy), or H; X<-> is a nonnucleophilic anion; provided that a salt is excluded wherein R<1>, R<2>, and R<3> are each phenyl, R<4> and R<5> are each H, R<6> is phenyl, R<7> and R<8> are each H, and R<9> is H, chloro, or nitro]. The compsn. is cured by exposure to rays of light with wavelengths of 200-500nm for 1sec to 5min followed by postcuring at 20-150 deg.C for 10hr or less.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cationically polymerizable composition such as an epoxy resin which has excellent storage stability, can be rapidly cured by light, and has good physical properties, and can be contained in such a composition. The present invention relates to a novel phosphonium salt that can serve as a photopolymerization catalyst.

[0002]

2. Description of the Related Art Generally, epoxy resins are excellent in mechanical, electrical and chemical properties, and are therefore used in various applications requiring high performance materials. Epoxy resin is
It is usually used as a so-called two-component system in which it is mixed with polyamines, carboxylic acid anhydrides and the like as a curing agent. Since these systems require metered mixing of each component immediately before use,
A one-component epoxy resin that does not require these steps is desired by the user. Although there are amine complex compounds such as dicyandiamide and boron monoethylamine fluoride as a curing agent and a catalyst that can cure an epoxy resin as a one-component system, curing takes several hours even at a temperature of 160 ° C. or higher. As a result, these one-part epoxy compositions cannot be used to coat heat-sensitive electronic components. Further, an accelerator such as an imidazole compound has been added to lower the curing temperature, but this has a drawback that storage stability is significantly deteriorated.

As a photopolymerization catalyst which does not require heating,
For example, aromatic diazonium salts have been proposed. This can be rapidly cured by irradiating an epoxy resin with light. However, the diazonium salt releases nitrogen by photolysis, which causes a problem that the cured product obtained thereby contains bubbles. In addition, the use of these substances is dangerous because the storage stability is poor due to the gradual polymerization even in a dark place and there is a risk of thermal instability and unlimited decomposition.

As an improvement on the above-mentioned problems, Japanese Patent Laid-Open No. 50-1
51996 and Japanese Patent Application Laid-Open No. 50-151997 (photo-curable compositions containing an aromatic iodonium salt and an aromatic sulfonium salt as a photopolymerization catalyst), but the curability is not yet sufficient.

Further, Japanese Patent Laid-Open No. 50-158698 discloses a phosphonium salt capable of releasing a Lewis acid by light irradiation to cure an epoxy resin. An epoxy cured product using this photocatalyst has alkali resistance. It is said to be inferior to.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to propose a polymerization catalyst capable of rapidly polymerizing and curing a cationically polymerizable compound by light, and containing such a polymerization catalyst, which is excellent in storage stability. Another object of the present invention is to provide a cationically polymerizable composition.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, by using a phosphonium salt represented by the following general formula (II) as a photopolymerization catalyst for a cationically polymerizable compound, the It has been found that a curable composition can be prepared, and the present invention has been completed based on this finding.
Among the phosphonium salts represented by the general formula (II), those represented by the general formula (I) are novel compounds.

That is, the present invention provides (a) a phosphonium salt represented by the following general formula (I):

[0009]

[Chemical 3]

(Wherein R ¹ , R ² and R ³ represent a phenyl group, a halogenated phenyl group, a cyanophenyl group, a benzoylphenyl group, an alkylphenyl group or an alkyl group, and R ⁴ and R ⁵ represent an alkyl group or Represents a hydrogen atom, R ⁶ represents a phenyl group, a naphthyl group, a pyrenyl group, an anthracenyl group or a styryl group, R ⁷ , R ⁸ and R ⁹ represent an alkyl group, an alkoxy group, a halogen atom,
It represents a nitro group, a hydroxyl group, a silyl group, a silyloxy group or a hydrogen atom. X ⁻ represents a non-nucleophilic anion.
Provided that R ¹ , R ² and R ³ are phenyl groups, R ⁴ and R ⁵ are hydrogen atoms, R ⁶ is a phenyl group, R ⁷ and R ⁸ are hydrogen atoms, and R ⁹ is a hydrogen atom, Those that are chloro or nitro are excluded. ), (B) as a cationically polymerizable compound and as a polymerization catalyst, the following general formula (II)
Photo-curable cationically polymerizable composition containing a phosphonium salt represented by

[0011]

[Chemical 4]

(Wherein R ¹ , R ² and R ³ represent a phenyl group, a halogenated phenyl group, a cyanophenyl group, a benzoylphenyl group, an alkylphenyl group or an alkyl group, and R ⁴ and R ⁵ represent an alkyl group or Represents a hydrogen atom, R ⁶ represents a phenyl group, a naphthyl group, a pyrenyl group, an anthracenyl group or a styryl group, R ⁷ , R ⁸ and R ⁹ represent an alkyl group, an alkoxy group, a halogen atom,
It represents a nitro group, a hydroxyl group, a silyl group, a silyloxy group or a hydrogen atom. X ⁻ represents a non-nucleophilic anion. ), And (c) a cured product obtained by photocuring the cationically polymerizable composition according to claim 2.

The non-nucleophilic anions in the general formulas (I) and (II) include SbF ₆ ⁻ , AsF ₆ ⁻ , PF ₆
^-, BF ₄ ^-, and the like. Further, the phosphonium salts of the general formulas (I) and (II) are cleaved by the radiant energy of light to generate a benzyl cation. It is considered that this causes the cationic polymerization reaction of the epoxy resin and the like to proceed to produce a corresponding cured product.

The present invention will be sequentially described below.

Preferred as the phosphonium salt represented by the general formula (I) in the present invention are benzyltriphenylphosphonium hexafluoroantimonate, p-chlorobenzyltriphenylphosphonium hexafluoroantimonate and p-methylbenzyltriphenyl. Phosphonium hexafluoroantimonate, p
-Methoxybenzyltriphenylphosphonium hexafluoroantimonate, α-methylbenzyltriphenylphosphonium hexafluoroantimonate, cinnamyltriphenylphosphonium hexafluoroantimonate, 2-hydroxy-5-nitrobenzyltriphenylphosphonium hexafluoroantimonate, 1 −
Naphthylmethyltriphenylphosphonium hexafluoroantimonate, 3-trimethylsilyl-4-trimethylsiloxybenzyl triphenylphosphonium hexafluoroantimonate, p-methoxybenzyl tris (p-chlorophenyl) phosphonium hexafluoroantimonate, p-methoxybenzyl tris (p -Methylphenyl) phosphonium hexafluoroantimonate, cinnamyltris (p-chlorophenyl) phosphonium hexafluoroantimonate, p-methoxybenzyl triphenylphosphonium hexafluorophosphate, 1-pyrenylmethyl-triphenylphosphonium hexafluoroantimonate, 1-pyrenylmethyl −
Butyldiphenylphosphonium hexafluoroantimonate, 9-anthracenylmethyl-triphenylphosphonium hexafluoroantimonate and the like can be mentioned. The above-mentioned compound can be obtained by a conventional method known per se, by preparing a phosphonium salt with a corresponding phosphine and a chlorinated product, and then performing salt exchange.

The cationically polymerizable compound which is the main component of the cationically polymerizable composition of the present invention is not particularly limited, and examples thereof include an epoxy resin.

The epoxy resin is also not particularly limited, and has an average of two or more epoxy groups per molecule. Preferred are polyglycidyl ethers obtained by reacting polyhydric alcohols such as glycerin and polyethylene glycol with epichlorohydrin, and cyclohexene or cyclopentene ring-containing compounds are epoxidized with an appropriate oxidizing agent such as hydrogen peroxide or peracid. Examples thereof include alicyclic epoxies such as cyclohexene oxide- and cyclopentene oxide-containing compounds obtained by the above. Typical examples of the above-mentioned epoxy resin are as follows when selected from commercial products. That is, as the alicyclic epoxy resin, "Celoxide 2021, 2000 and 3000" and "E
HPE-3150-1 "(all manufactured by Daicel Chemical Industries Ltd.);" ERL4206, 4221, 4299 and 4234 "(all Union Carbide Corporation)
Manufactured by Ciba-Geigy Co., Ltd.) and the like. Also,
As an aromatic epoxy resin, polyphenols such as bisphenol A, bisphenol F, bisphenol AD, catechol, and resorcinol, or hydroxycarboxylic acids such as p-hydroxybenzoic acid and β-hydroxynaphthoic acid are obtained by reacting with epichlorohydrin. And polyglycidyl ethers; polyglycidyl esters obtained by reacting polycarboxylic acids such as phthalic acid and terephthalic acid with epichlorohydrin; and the like. Furthermore, epoxidized phenol novolac resin,
Examples thereof include epoxidized cresol novolac resin, epoxidized polyolefin, and urethane-modified epoxy resin.

Other cationically polymerizable compounds include:
Styrene, cyclic ether, vinyl ether, lactone,
Examples include cyclic carbonates and the like.

In preparing the cationically polymerizable composition of the present invention, the compounding ratio of the phosphonium salt to the cationically polymerizable compound is wide because it is in a substantially inactive state unless the salt is activated by light or heat. You can change the range. The phosphonium salt may be used in a proportion of 0.1 to 20 parts by weight based on the weight of the curable composition. However, the amount can be increased or decreased depending on factors such as the nature of the cationically polymerizable compound, the intensity of irradiation, the required curing time, the physical properties of the cured product and the cost.

The cationically polymerizable composition of the present invention can be cured by a method such as room temperature photocuring, heat photocuring, and post-curing after photocuring, so that it is not clearly understood from the context. In the present invention, these may be collectively referred to simply as photocuring. Therefore, it should be noted that the photocuring referred to in the present invention is broadly defined. Therefore, for example, heating photocuring means photocuring by the combined use of heating and light irradiation. The wavelength required for photocuring is 200 to 500 nm. Light irradiation time is 1 to 5
Minutes, preferably 5 seconds to 2 minutes. The temperature at the time of photocuring by heating is usually 20 to 150 ° C. After-curing after photocuring is, for example, at 20 to 150 ° C. and within 10 hours.

In the cationically polymerizable composition according to the present invention, various additives such as a filler, a diluent, a solvent, a pigment, a flexibility-imparting agent, a sensitizer and an antioxidant are added, if necessary or desired. Can be added.

Examples of the light source for photocuring in the present invention include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp and a carbon arc lamp.

The cured product obtained by photocuring the cationically polymerizable composition of the present invention in this manner is excellent in water resistance, chemical resistance, electrical characteristics and the like.

[0024]

The present invention will be described in more detail with reference to the following examples.

Example 1 (a) Synthesis of benzyltriphenylphosphonium hexafluoroantimonate A 1-liter 4-necked flask equipped with a stirrer, a reflux condenser, and a thermometer was purged with nitrogen, and then triphenylphosphine 52 was added thereto. 0.4 g
(0.2 mol) and 200 ml of acetonitrile were added, mixed and dissolved, and benzyl chloride 25.3 dissolved in 100 ml of acetonitrile under heating and reflux conditions with stirring.
g (0.2 mol) was added dropwise over 1 hour, and the reaction was continued under heating and refluxing conditions for 5 hours with stirring. As a result, white crystals were precipitated.

Then, the mixture was cooled to room temperature, and the precipitated crystals were separated by filtration and dried to obtain 67.5 g of benzyltriphenylphosphonium chloride (yield 86.7%). The melting point of this benzyltriphenylphosphonium chloride was 287 to 288 ° C.

19.4 g (0.05 mol) of benzyltriphenylphosphonium chloride thus obtained was dissolved in 200 ml of methanol-water (1/1 (volume ratio)) and placed in a flask of the same volume to obtain 30 in the given solution
When 12.9 g (0.05 mol) of sodium hexafluoroantimonate dissolved in 0 ml of water was added dropwise with stirring, a precipitate was generated, which turned cloudy and became a slurry.

After completion of the dropping, stirring was continued at room temperature for 1 hour, and then the crystals were separated by filtration and recrystallized from methanol.
24.5 g (yield 83.0%) of benzyltriphenylphosphonium hexafluoroantimonate was obtained.
The melting point of this benzyltriphenylphosphonium hexafluoroantimonate was 172 ° C.

Further, elemental analysis of the above benzyltriphenylphosphonium hexafluoroantimonate was carried out. The results are shown in Table 1.

[0030]

[Table 1]

(B) 1.8 parts by weight of the above benzyltriphenylphosphonium hexafluoroantimonate was added to a bisphenol A type epoxy resin "Epicoat 828".
(Yukaka Shell Epoxy Co., Ltd. product name, epoxy equivalent 1
90) Dissolved in 100 parts by weight to obtain a uniform polymerizable composition.

This was applied on a glass epoxy substrate to a thickness of 0.015 mm. High pressure mercury lamp (120W
/ Cm) was irradiated with ultraviolet rays from a distance of 17 cm, and it became tack-free in 36 seconds (curing time). Furthermore, the pot life of this polymerizable composition at 40 ° C. in the dark was 6 months or more, and the storage stability was good.

Examples 2 to 11 Various phosphonium salts shown in Table 2 were synthesized in the same manner as in Example 1.

The epoxy resin of Example 1 and the second resin
Another polymerizable composition was prepared using the phosphonium salts shown in the table, and each phosphonium salt was UV-cured in the same manner as in Example 1. The results are also shown in the table. Further, all of these photocurable compositions were uniform, and the pot life test showed that the storage stability was 6
It was a good one over a month.

The cured products obtained by curing these compositions with ultraviolet light in this manner did not generate air bubbles at all, and no odor was generated from these cured products.

[0036]

[Table 2]

Example 12 2.5 parts by weight of benzyltriphenylphosphonium hexafluoroantimonate was added to an alicyclic epoxy resin "Celoxide 2021" ((3,4-
Epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate) was dissolved in 100 parts by weight to obtain a uniform polymerizable composition.

This was applied to a glass epoxy substrate with a thickness of 0.015 mm. High pressure mercury lamp (120W
/ Cm), it was tack-free in 6 seconds when it was irradiated with ultraviolet rays from a distance of 17 cm. Furthermore, the pot life of this polymerizable composition at 40 ° C. in the dark is 6
The storage stability was good for more than a month.

Examples 13 to 22 In the same manner as in Example 12, various phosphonium salts shown in Table 3 were UV-cured. The results are also shown in the table. Moreover, all of these photopolymerizable compositions were uniform, and the pot life test showed that the storage stability was good, being 6 months or more.

The cured products obtained from the composition of the present invention did not generate air bubbles at all, and no odor was generated from these cured products.

[0041]

[Table 3]

Example 23 2.1 parts by weight of p-methoxybenzyl tris (p-chlorophenyl) phosphonium hexafluoroantimonate was added to a bisphenol A type epoxy resin "Epicoat 82".
8 "was dissolved in 100 parts by weight to obtain a uniform photopolymerizable composition.

This was applied on a glass epoxy substrate to a thickness of 0.015 mm. High pressure mercury lamp (120W
/ Cm) and ultraviolet rays were irradiated from a distance of 17 cm for 6 seconds, and then cured by after-curing at 100 ° C. for 30 minutes. Furthermore, this photopolymerizable composition is kept at 40 ° C. in the dark.
The pot life was 6 months or more, and the storage stability was good.

Example 24 Synthesis of 1-pyrenylmethyl-triphenylphosphonium hexafluoroantimonate Phosphorus oxychloride (7.0 g, 46 mmol) was slowly added dropwise to DMF (10 ml) under a blanket of argon.
The resulting solution was cooled to room temperature and pyrene (9.2 g, 4
5 mmol) in chloroform (50 ml) was added dropwise. After completion of dropping, after stirring at room temperature for 24 hours,
It was added to water (300 ml) and extracted with chloroform. The chloroform layer was washed several times with a saturated aqueous solution of sodium hydrogen carbonate and dried over magnesium sulfate. The yellow solid obtained by drying the solvent under reduced pressure was purified by column chromatography to give 1-formylpyrene (2.5 g, yield 24).
%) Was obtained.

Subsequently, 1-formylpyrene (2.3 g,
10 mmol) was dissolved in THF (20 ml), sodium borohydride (0.10 g, 2.6 mmol) was added, and the mixture was stirred at room temperature for 30 minutes. Methanol (20 ml)
After adding, the mixture was further stirred for 6 hours. The reaction solution was mixed with water (1
(00 ml) and extracted with chloroform. The chloroform layer was washed several times with saturated aqueous sodium chloride solution and dried over magnesium sulfate. The pale yellow solid obtained by distilling off the solvent under reduced pressure was purified by column chromatography to obtain 2.2 g of 1-hydroxymethylpyrene (yield 95
%) Was obtained.

Next, 1-hydroxymethylpyrene (1.0 g, 4.3 mmol) was added to thionyl chloride (5 ml) and the mixture was stirred at room temperature for 3 hours, and then excess thionyl chloride was distilled off under reduced pressure. Further, dry toluene (20 ml) was added to the residue, and this was distilled off under reduced pressure. Triphenylphosphine (1.2 g, 4.6 mmol) and toluene (10 ml) were added to the obtained yellow solid, and the mixture was heated under reflux for 6 hours. After cooling, hexane (50 ml) was added, and the precipitate was filtered off by suction filtration. The obtained crystals were washed several times with hexane to obtain 1-pyrenylmethyl-triphenylphosphonium chloride (1.6 g, yield 71%).

Further, 1-pyrenylmethyl-triphenylphosphonium chloride (1.5 g, 29 mmol)
Was dissolved in methanol (20 ml) and stirred under stirring to prepare a 5% potassium hexafluoroantimonate aqueous solution (20
ml) was added. The generated precipitate was filtered by suction filtration, washed with water several times, and then dried under reduced pressure at 100 ° C. The obtained crystals were dissolved in a small amount of acetone, ether was gradually added dropwise thereto, and the brown tar-like substance that had precipitated was removed by decantation. Further, ether (100 to 200 ml) was added to the supernatant, the pale yellow powder which had precipitated was separated by filtration, and dried under reduced pressure at 100 ° C. The precipitation operation was repeated 5 times to obtain pure 1-pyrenylmethyl-triphenylphosphonium hexafluoroantimonate 4.8.
g (yield 62%) was obtained. The melting point of this compound is 274 ° C.
Met.

Example 25 Synthesis of 1-pyrenylmethyl-butyldiphenylphosphonium hexafluoroantimonate Chlorodiphenylphosphine (6.5 g, 30 mmol) was dissolved in dry ether (50 ml) and stirred vigorously under argon at 50 ° C. A 62M n-butyllithium hexane solution (22 ml) was slowly added dropwise so that the ether did not reflux. After the dropping was completed, the mixture was further stirred at room temperature for 2 hours. After the generated precipitate was filtered off, the filtrate was washed with water several times and dried over magnesium sulfate. The pale yellow oily product obtained by distilling off the solvent under reduced pressure was further purified by distillation under reduced pressure to obtain 4.3 g of butyldiphenylphosphine (yield 59%).

Next, 1-hydroxymethylpyrene (1.0 g, 4.3 mmol) was added to thionyl chloride (5 ml) and the mixture was stirred at room temperature for 3 hours, and then excess thionyl chloride was distilled off under reduced pressure. Further, dry toluene (20 ml) was added to the residue, and this was distilled off under reduced pressure. Butyldiphenylphosphine (3.3 g, 14 mmol) was added to the obtained yellow solid.
And toluene (10 ml) were added, and the mixture was heated under reflux for 6 hours. After cooling, hexane (50 ml) was added and the precipitate was filtered off by suction filtration. The obtained crystals were washed several times with hexane to obtain 2.0 g of 1-pyrenylmethyl-butyldiphenylphosphonium chloride (yield 31%).

Furthermore, 1-pyrenylmethyl-butyldiphenylphosphonium chloride (1.5 g, 30 mmol) was dissolved in methanol (20 ml), and with stirring, the 5% potassium hexafluoroantimonate aqueous solution (20 ml) prepared immediately before was dissolved. added. The generated precipitate was filtered by suction filtration, washed with water several times, and then dried under reduced pressure at 100 ° C. The obtained crystals were dissolved in a small amount of acetone, ether was gradually added dropwise thereto, and the brown tar-like substance that had precipitated was removed by decantation. Further, ether (100 to 200 ml) was added to the supernatant, the pale yellow powder which had precipitated was separated by filtration, and dried under reduced pressure at 100 ° C. This precipitation operation was repeated 5 times to obtain 0.84 g (yield 40%) of pure 1-pyrenylmethyl-butyldiphenylphosphonium hexafluoroantimonate. The melting point of this compound was 214 ° C.

Example 26 9-anthracenylmethyl-triphenylphosphonium hexafluoroantimonate was synthesized in the same manner as in Example 24. The melting point of this compound was 227 ° C.

[0052]

The cationically polymerizable composition containing the phosphonium salt of the present invention as a polymerization catalyst can be stored for a long period of time, has a function of rapidly curing upon irradiation with light, has no hygroscopicity, and is water and water resistant. Since it gives a cured product with excellent chemical and electrical properties, it is suitable for applications such as plastic protection, decorative and insulating coatings, printing inks, sealants, adhesives, photoresists, impregnation casting, stereolithography, etc. .

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kenji Ohashi 2171 Sakai, Atsugi-shi, Kanagawa (72) Inventor Kenichi Mori 1-1, Suzuki-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Ajinomoto Co., Inc. Central Research Laboratory

Claims (3)

[Claims] 1. A phosphonium salt represented by the following general formula (I): (Wherein R ¹ , R ² and R ³ represent a phenyl group, a halogenated phenyl group, a cyanophenyl group, a benzoylphenyl group, an alkylphenyl group or an alkyl group, and R ⁴
And R ⁵ represents an alkyl group or a hydrogen atom, R ⁶ represents a phenyl group, a naphthyl group, a pyrenyl group, an anthracenyl group or a styryl group, and R ⁷ , R ⁸ and R ⁹ represent an alkyl group, an alkoxy group, a halogen atom, It represents a nitro group, a hydroxyl group, a silyl group, a silyloxy group or a hydrogen atom. X ⁻ represents a non-nucleophilic anion. However,
R ¹ , R ² and R ³ are phenyl groups, and R ⁴ and R ⁵
Is a hydrogen atom, R ⁶ is a phenyl group, and R ⁷ and R
Except those in which ⁸ is a hydrogen atom and R ⁹ is a hydrogen atom, a chloro group or a nitro group. ). 2. A photo-curable cationically polymerizable composition containing a cationically polymerizable compound and a phosphonium salt represented by the following general formula (II) as a polymerization catalyst: (Wherein R ¹ , R ² and R ³ represent a phenyl group, a halogenated phenyl group, a cyanophenyl group, a benzoylphenyl group, an alkylphenyl group or an alkyl group, and R ⁴
And R ⁵ represents an alkyl group or a hydrogen atom, R ⁶ represents a phenyl group, a naphthyl group, a pyrenyl group, an anthracenyl group or a styryl group, R ⁷ , R ⁸ and R ⁹ represent an alkyl group, an alkoxy group, a halogen atom, It represents a nitro group, a hydroxyl group, a silyl group, a silyloxy group or a hydrogen atom. X ⁻ represents a non-nucleophilic anion. ). 3. A cured product obtained by photocuring the cationically polymerizable composition according to claim 2.