JP2706833B2 - Cationic polymerization initiator and polymerizable composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cationically polymerizable composition, a polymerization initiator, and a polymerization method. More specifically, in order to polymerize a cationically polymerizable substance in a short time by radiation such as light or an electron beam and / or heat to obtain a cured product having good physical properties and a practical oligomer of a cationically polymerizable vinyl compound. A polymerization composition, an initiator for the polymerization and a polymerization method.

[Prior art and problems to be solved] In general, cationically polymerizable substances, especially epoxy resins, are used in various applications requiring high-performance materials. In particular, the method of polymerizing and curing by irradiation of radiation having a predetermined wavelength such as ultraviolet light can be cured in a short time, and the polymerization step is simple, so that it is used for various applications.

Conventionally, epoxy resins contain an active amine-containing compound or a carboxylic anhydride as a curing agent, and are widely used in a two-part system. However, a two-part system using these curing agents requires that the components be completely mixed, and the curing time is several hours.

There is a boron fluoride-monoethylamine system for curing the epoxy resin as a one-part system, which requires 1 to 8 hours at 160 ° C. or higher. U.S. Pat. No. 3,586,561, which is an improvement, also requires high temperatures. Therefore, these compositions cannot be used for coating heat-sensitive electronic components and the like.

Further, a metal halide compound aryldiazonium salt has been proposed for curing an epoxy resin by light. However, they are expected to polymerize rapidly and are subject to premature gelling, resulting in compositions that cannot be stored satisfactorily even in the dark. It has been proposed to provide an epoxy material containing a metal halide aryldiazonium salt to prevent premature gelling of the composition and to provide shelf life in the dark, but at the cost of increased and completely satisfactory No results were obtained. In addition, these compositions have the problem that the cured material obtained therefrom contains undesirable bubbles because nitrogen is released during curing.

By the way, various photodecomposable sulfonium salts are known as onium salts. For example, JP-A-54-53181 discloses that a p-hydroxyphenyldimethylsulfonium hexafluoroarsenate is used as a photocuring agent, and JP-A-50-151997 discloses that a phenylsulfonium salt is used as a photocuring agent for epoxy. It is known that
However, although these cure the epoxy resin with light, the application of heat alone cannot cure the epoxy resin. In the above disclosure, the following general formula [I]
Is not included.

On the other hand, heat latent initiators capable of activating an onium salt by applying heat and curing an epoxy resin are disclosed in JP-A-58-37003 and JP-A-63-223002.
Discloses a benzylsulfonium salt such as a dialkylbenzylsulfonium hexafluoroantimonate salt, and JP-A-56-152833 reports a trialkyl sulfonium salt.

However, this sulfonium salt is inactive to light, cannot cure the epoxy resin in a short time, and requires a temperature of 150 ° C. or higher, and is not practical in terms of heating time and temperature.

As for special esters such as spiro-type esters, JP-A-60-188425 discloses a curing agent for the heat polymerization.

On the other hand, as cationic polymerization initiators of cationically polymerizable vinyl compounds, mineral acids, Lewis acid type initiators such as BF ₃ , ZnCl ₂ , and AlCl ₃ and halogen-containing organic aluminum compounds such as AlR ₂ Cl and AlRCl ₂ are known. It is. However, at a temperature of 0 ° C. or higher, the cationic polymerization reaction of these initiators is too violent, and the control of the polymerization reaction cannot be controlled as desired and the degree of polymerization does not increase. Of course, the cationically polymerizable monomer and these initiators are pre-liquefied at 0 ° C. or higher,
It is impossible to save.

In order to polymerize a vinyl compound, it is necessary to control a chain transfer reaction and a termination reaction. Usually, after cooling a cationic polymerizable monomer dissolved in an appropriate solvent to a predetermined cryogenic temperature, an initiator liquid is charged and polymerization is performed. The reaction takes place. However, the polymerization reaction is industrially performed at a very low temperature (for example, -130 to
In order to perform the process at -40 ° C), it is necessary to use a low-temperature refrigerant, so that the operation is complicated, and the cooling cost is increased.

In addition, U.S. Pat. No. 3,283,010 describes release of benzyl cations, but this publication does not intend to polymerize polymers.

[Object of the Invention] An object of the present invention is to polymerize a cationically polymerizable substance such as an epoxy resin with radiation and / or heat,
And also, under light shielding, excellent storage stability at 10 ° C. or less, provides a cationically polymerizable composition used as a sealant, a matrix resin for a composite material, and a method of polymerization thereof, a polymerization initiator. It is to propose.

Or, while polymerizing a cationically polymerizable vinyl compound such as styrene under certain conditions, while providing a monomer composition having excellent storage stability at 10 ° C or lower under a light-shielded mixture of a polymerization initiator and Another object of the present invention is to industrially provide a practical oligomer of a vinyl compound and propose a polymerization method and a polymerization initiator.

[Means for Solving the Problems] The present inventors have conducted intensive studies in order to solve the above-described problems, and as a result, have arrived at the present invention.

That is, the present invention provides a polymerizable composition comprising a cationic polymerizable substance, a sulfonium salt represented by the following general formula [I], which can be polymerized by radiation and / or heat, and a general formula [I] The present invention also relates to a polymerization initiator containing as a main component, and a polymerization method.

(However, R ₁ represents any _one of hydrogen, methyl, acetyl, methoxycarbonyl, ethoxycarbonyl, benzyloxycarbonyl, benzoyl, phenoxycarbonyl, 9-fluorenylmethoxycarbonyl, R ₂ , R ₃ is independently hydrogen, halogen, or a C ₁ -C ₄ alkyl group, R ₄ is a C ₁ -C ₄ alkyl group, and Q is o-
One of nitrobenzyl, m-nitrobenzyl, dinitrobenzyl, trinitrobenzyl, α-naphthylmethyl, and β-naphthylmethyl. X is Sb
One of F ₆ , AsF ₆ , PF ₆ and BF ₄ . [Constitution of the Invention] The polymerization initiator of the present invention comprises a pair of a nitro-substituted benzyl-4-substituted or unsubstituted oxyphenylsulfonium ion or a naphthylmethyl-4-substituted or unsubstituted oxyphenylsulfonium ion with a predetermined anion. And these are the constituent requirements. The cationically polymerizable substance used in the present invention is preferably an acid-polymerizable or acid-curable substance, particularly preferably an epoxy resin.

Examples of suitable materials include epoxide monomers, episulfide monomers, polyepoxides (or epoxy resins), polyepisulfides (or episulfide resins), phenol / formaldehyde resins, melamine / formaldehyde resins, urea / Cyclic ethers and thioethers (other than epoxides and episulfides) such as formaldehyde resins, spiro orthoesters, bicycloorthoesters, spiroorthocarbonates and their polymers, lactones, styrene, vinyl ethers and vinyl thioethers and acids A resin containing a cross-linking agent that cross-links or cures the resin when treated.
A mixture of more than one type is also acceptable.

[Action] The sulfonium salt used as such a polymerization initiator of the present invention is as described above. This sulfonium salt alkylates the corresponding 4-mercaptophenol, and further reacts with the corresponding halide. A high yield can be obtained by synthesizing a sulfonium salt having a halogen ion and then performing anion exchange with a predetermined complex salt.

Preferred as the sulfonium salt in the present invention,
o-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, m-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, o-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, m-nitro Benzyl-4-hydroxyphenylmethylsulfonium hexafluoroarsenate, 3,5-dinitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 3,5-dinitrobenzyl-4-hydroxyphenylethylsulfonium hexafluoroantimonate, o -Nitrobenzyl-4-hydroxyphenylethylsulfonium hexafluoroantimonate, o
-Nitrobenzyl-3-chloro-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 2,4,6-trinitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 2,4-dinitrobenzyl-4-hydroxy Phenylmethylsulfonium hexafluorophosphate, α
-Naphthylmethyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, β-naphthylmethyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, α-naphthylmethyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, α-naphthylmethyl And 4- (benzyloxycarbonyloxy) phenylmethylsulfonium hexafluoroantimonate, α-naphthylmethyl-4- (methoxycarbonyloxy) phenylmethylsulfonium hexafluoroantimonate and the like.

The sulfonium salt used in the present invention not only increases activity against radiation such as light and electron beams, but also has activity against heat. That is, it is considered that these sulfonium salts excited by radiation or heat release a benzyl cation or a naphthylmethyl cation and promote the polymerization of the above-mentioned cationically polymerizable substance.

In the present invention, when the cationically polymerizable substance is a vinyl compound, a solution polymerization method using an inert solvent as an initiator or a monomer is usually performed during the polymerization reaction. Will be Examples of the solvent include toluene, benzene, aromatic hydrocarbons such as xylene, n-hexane, aliphatic hydrocarbons such as n-heptane, alicyclic hydrocarbons such as cyclohexane, petroleum ether, Hydrocarbon mixtures such as ligroin, halogenated hydrocarbons such as chlorobenzene and dichloroethane can be used, and the polymerization reaction of these vinyl compounds is carried out under normal pressure or under pressure, and the reaction temperature is 20 ° C. or higher. Temperature, preferably industrially easy to heat
70-150 ° C.

In addition, the sulfonium salt used as a polymerization initiator in the present invention does not initiate a cationic polymerization reaction at 10 ° C. or less under light shielding, so that if necessary, a monomer and an initiator are liquidized in advance using an appropriate solvent and stored. Or commercialized.

The sulfonium salt used in the present invention is 0.01 to 20 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resin. If the amount is less than 0.01 part by weight, a sufficient polymer cannot be obtained. If the amount exceeds 20 parts by weight, favorable properties cannot be obtained after polymerization, which is not preferred in terms of cost. Further, the polymerization curing is carried out by a radiation treatment or a heat treatment, and if necessary, the heating and the radiation irradiation can be used in combination. At the time of polymerization, a solvent can be used if necessary.

As the radiation according to the present invention, ultraviolet rays having a wavelength in the range of 200 to 400 nm are most efficiently used. Can be polymerized and cured by irradiation. Further, polymerization and curing can be performed by irradiation with an electron beam.

In some cases, the composition of the present invention is further used by mixing an extender, a flame retardant, an antistatic agent, a surfactant, an auxiliary represented by an acid anhydride, and the like.

The composition of the present invention can be used for polishing varnishes, inks, paints, adhesives, laminates, prepregs, molding materials, sealing materials, and the like.

The curable composition of the present invention has a function that can be stored for a long period of time and rapidly initiates polymerization by irradiation with radiation such as light or an electron beam or heating at 150 ° C. or less or a combination of heating and radiation treatment. It gives a cured product that is excellent in water resistance, chemical resistance and electrical properties without moisture absorption.

Another characteristic of the cationically polymerizable vinyl compound composition is that it allows one-part storage of monomers and initiators, which was difficult in the past, and also enables cationic polymerization at 20 ° C or higher, and is practical with simple heating. The point is that it has become possible to obtain a polymer having a high degree of polymerization.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following.

Example 1 0.034 g of α-naphthylmethyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate was mixed with 1.0 g of phenylglycidyl ether.
This mixture was degassed and sealed, and subjected to bulk polymerization at a predetermined temperature for 1 hour. After the reaction, the conversion was determined from the ¹ H NMR spectrum. The results are shown below.

Example 2 Example 1 against 1.0 g of phenylglycidyl ether
0.034 g of the sulfonium salt used in the above was mixed, and the tube was degassed and sealed. Using a 400 W high-pressure mercury lamp with a main wavelength of 312 nm as a light source, using a rotary photochemical reactor (RH400-10W type) manufactured by Riko Kagaku Sangyo, light bulk polymerization was performed at 10 ° C. Was 65%.

Example 3 1 g of o-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate was dissolved in 100 g of Epicoat 828 (a bisphenol A type epoxy resin manufactured by Yuka Shell Epoxy) and the thickness was 0.5 mm.
On a glass plate. When this was irradiated with sunlight for 5 hours, the resin was completely gelled.

Examples 4 to 12 Formulations comprising 100 parts by weight of Epikote 828 (bisphenol A type epoxy resin manufactured by Yuka Shell Epoxy) and various parts and 3 parts by weight of a sulfonium salt were prepared, and about 100 mg each was taken and heated to 150 ° C. The gel time was measured on the plate.
Table 1 shows the results. When the composition prepared here was allowed to stand at 10 ° C. for 1 month under light shielding, no remarkable thickening was observed.

Example 13 1-phenyl-4-ethyl-2,6,7-trioxabicyclo [2,2,2] octane was added to 0.5 g of α-naphthylmethyl-4-hydroxyphenylmethylsulfonium
Mix 0.015 g of hexafluoroantimonate, degas,
Sealed. This mixture was subjected to bulk polymerization at 120 ° C. for 20 hours. After polymerization, 100% conversion was confirmed from the ¹ H NMR spectrum. The polymer was then dissolved in 2 ml of methylene chloride and poured into 100 ml of hexane. The hexane-insoluble portion was dried to obtain 0.35 g of a polymer.

Example 14 0.01 g of o-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate based on 0.5 g of 3,9-dibenzyl-1,5,7,11-tetraoxaspiro [5,5] undecane Mix, degas, and seal. This mixture was subjected to bulk polymerization at 150 ° C. for 2 hours. After the polymerization, a conversion rate of 95% was confirmed from the ¹ H NMR spectrum.

Next, the polymer was dissolved in 2 ml of methylene chloride, and hexane 1
Injected into 00 ml. Then, the hexane-insoluble part is dried,
0.40 g of the polymer was obtained.

Example 15 O-nitrobenzyl-based on 0.5 g of purified styrene
0.010 g of 4-hydroxyphenylmethylsulfonium hexafluoroantimonate was mixed, degassed and sealed. Then, polymerization was carried out at 100 ° C. with stirring. After 60 minutes,
The solidified reaction solution was dissolved in 2 ml of carbon tetrachloride, and the ¹ H NMR
A conversion of 89% was confirmed from the spectrum.

Next, this was poured into methanol to terminate the polymerization and precipitate a polymer. The purified and dried polymer was white crystals with a yield of 75%.

GPC (polystyrene equivalent): ▲ ▼ = 380
0, ▲ ▼ / ▲ ▼ = 1.89.

Examples 16 to 22 According to Example 15, styrene was polymerized using various sulfonium salts.

 Table 2 shows the results.

Example 23 Styrene was polymerized at 60 ° C. for 60 minutes using the same composition as in Example 15, but the conversion was 0%.

Example 24 10 g of purified styrene and 0.30 g of o-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate were dissolved in 20 ml of chlorobenzene, degassed and sealed, and allowed to stand at 10 ° C for 1 month under light shielding. In addition, polymerization of styrene did not occur.

[Effect of the Invention] As described above, the predetermined sulfonium salt according to the present invention is:
It is effective as a polymerization initiator for cationically polymerizable substances, and a polymerization composition containing these can be polymerized and cured by a method of irradiation with radiation such as light or an electron beam and / or a heat treatment. The one-part composition is stable even after mixing, and has excellent storage properties under the conditions described above. Therefore, the intended purpose can be achieved.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-145459 (JP, A) JP-A-3-59001 (JP, A) JP-A-3-17101 (JP, A) JP-A-3-3100 200761 (JP, A) JP-A-2-196812 (JP, A) JP-A 2-1470 (JP, A) JP-A 3-205405 (JP, A)

Claims (15)

(57) [Claims] 1. A polymerizable composition comprising one or more cationically polymerizable substances and a sulfonium salt represented by the general formula [I]. (However, R ₁ represents any _one of hydrogen, methyl, acetyl, methoxycarbonyl, ethoxycarbonyl, benzyloxycarbonyl, benzoyl, phenoxycarbonyl, 9-fluorenylmethoxycarbonyl, R ₂ , R ₃ is independently hydrogen, halogen, or a C ₁ -C ₄ alkyl group, R ₄ is a C ₁ -C ₄ alkyl group, and Q is o-
One of nitrobenzyl, m-nitrobenzyl, dinitrobenzyl, trinitrobenzyl, α-naphthylmethyl, and β-naphthylmethyl. X is Sb
One of F ₆ , AsF ₆ , PF ₆ and BF ₄ . ) 2. The polymerizable composition according to claim 1, wherein the cationically polymerizable substance is a compound having an epoxy group. 3. The polymerizable composition according to claim 1, wherein the cationically polymerizable substance is a cationically polymerizable vinyl compound. 4. The polymerizable composition according to claim 1, wherein the cationically polymerizable substance is a compound having one or more of spiro orthoester groups, bicycloorthoester groups, and spiroorthocarbonate groups. Stuff. 5. The polymerizable composition according to claim 1, wherein 0.01 to 20 parts by weight of a sulfonium salt represented by the general formula [I] is added to 100 parts by weight of the cationically polymerizable substance. 6. A compound of the general formula [I] according to claim 1.
A polymerization initiator of a cationically polymerizable substance containing a sulfonium salt as a main component. 7. The sulfonium salt is m-nitrobenzyl-4.
7. The polymerization initiator according to claim 6, which is -hydroxyphenylmethylsulfonium hexafluoroantimonate. 8. The method according to claim 1, wherein the sulfonium salt is α-naphthylmethyl-4.
7. The polymerization initiator according to claim 6, which is -hydroxyphenylmethylsulfonium hexafluoroantimonate. 9. The sulfonium salt is α-naphthylmethyl-4.
7. The polymerization initiator according to claim 6, which is-(benzyloxycarbonyloxy) phenylmethylsulfonium hexafluoroantimonate. 10. The sulfonium salt is α-naphthylmethyl-
The polymerization initiator according to claim 6, which is 4- (methoxycarbonyloxy) phenylmethylsulfonium hexafluoroantimonate. 11. One or more of the cationically polymerizable substances are added with one or more of the sulfonium salts represented by the general formula [I] of claim 1 as an initiator, and this is irradiated with radiation. And / or polymerization by heat. 12. The method according to claim 1, wherein the radiation is ultraviolet light.
Item 12. The polymerization method according to Item 11, 13. The method according to claim 1, wherein the radiation is sunlight.
Item 12. The polymerization method according to Item 11, 14. The method according to claim 11, wherein the polymerization is carried out at a temperature of 20 ° C. or higher. 15. A method according to claim 1, wherein 0.01 to 20 parts by weight of a sulfonium salt represented by the general formula [I] is added to 100 parts by weight of the cationically polymerizable substance. Item 12. The polymerization method according to Item 11.