JPH1129640A - Production of photo cation curable composition and photo cation curable hard coating agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject curable composition excellent in photo cation curability and capable of forming cured coating films having high hardness degrees by hydrolyzing a silicone compound having a specific group. SOLUTION: This method for producing the photo cation curable composition comprising a silsesquioxane compound comprises hydrolyzing a silicone compound of formula I (R<0> is an organic functional group having an oxetanyl group; X is a hydrolyzable group) as a raw material in the presence of an alkali agent (preferably a quaternary ammonium salt) at a pH of 9-13 at 20-80 deg.C for 4-24 hr. The compound of formula I is obtained by addition-reacting an oxetane compound having an alkenyl terminal (preferably allyl group) to a compound of formula II in the presence of a group 8 metal catalyst (preferably an organic platinum complex), and all hydrolyzable groups in the compound of formula II are preferably condensed. The silsesquioxane compound preferably has a number-average mol.wt. of 1000-3000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a cationic photocurable composition and a cationic photocurable hard coat composition obtained by the method. The photocationically curable composition produced by the method of the present invention is suitable as a photocationically curable hard coat agent composition since it has excellent photocurability and forms a high hardness film.

[0002]

2. Description of the Related Art In the field of ultraviolet (UV) -initiated polymerization or ultraviolet-initiated curing, photoinitiated radical polymerization using polyfunctional acrylates and unsaturated polyesters has been widely studied and industrially used.

However, there is a problem that this radical polymerization is inhibited by oxygen in the air or the like. Especially when the coating composition is cured by radical polymerization,
As the composition becomes thinner, the influence of polymerization inhibition by oxygen becomes more remarkable, and there is a limitation that the composition must be cured under an inert atmosphere in order to cure the composition quickly and completely. On the other hand, the photo-initiated cationic polymerization is not affected by polymerization inhibition by oxygen, unlike the photo-initiated radical polymerization, and thus can be completely polymerized even in the air.

[0004] Representative monomers used for photoinitiated cationic polymerization include epoxides and vinyl ethers. In particular, according to the composition using epoxide as a monomer, it is possible to obtain a cured product having good heat resistance, excellent adhesive strength, and good chemical resistance.

[0005] Silsesquioxane represented by the general formula (RSi03 _{/ 2} ) _n is a general term for a series of network-like polysiloxanes having a ladder-like, cage-like, and three-dimensional knitted (random) structure. is there. This silsesquioxane, unlike silica, which is a completely inorganic substance, is soluble in general organic solvents, so that it is easy to handle and has excellent processability such as film formation and excellent moldability. . Conventionally, silsesquioxane compounds having an epoxy group introduced include those obtained by hydrolyzing (3-glycidoxypropyl) trimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, or the like. Known (Chemical Reviews, 1995, Vol.95,
No.5).

[0006]

However, a composition comprising a photocurable monomer of the epoxide type has a relatively low photopolymerization rate of the epoxy group, and therefore, such a composition is rapidly applied particularly when coated on paper or plastic. It is difficult to say that it is not necessarily suitable for applications requiring high photocurability.
On the other hand, since the photopolymerization rate of an oxetanyl group is usually significantly higher than that of an epoxy group, a composition comprising the compound having the oxetanyl group, particularly a silsesquioxane compound having the above-described features, A compound having an oxetanyl group is useful as a photocationically curable composition.

An object of the present invention is to provide a method for producing a cationic photocurable composition comprising a silsesquioxane compound having an oxetanyl group. Another object of the present invention is to provide a cationic photocurable hard coat composition comprising the cationic photocurable composition obtained by the above production method.

[0008]

Means for Solving the Problems The present inventors have found that a composition obtained by hydrolyzing a silicon compound having an oxetanyl group and a hydrolyzable group has excellent photocationic curability and high hardness by curing. The inventors have found that a film is formed and completed the present invention.

That is, the method for producing the cationic photocurable composition of the first invention according to the present invention is a method for producing a cationic photocurable composition comprising a silsesquioxane compound having an oxetanyl group, and comprises the following formula ( The compound represented by the structural formula shown in I) is hydrolyzed in an atmosphere having a pH of 7 or more.

[0010]

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In the above formula (I), R ⁰ is preferably an organic functional group represented by the following structural formula (II), as in the second invention.

[0012]

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X in the above formula (I) is preferably an alkoxy group, a cycloalkoxy group or an aryloxy group as in the third invention.

The cationically photocurable compositions obtained by the production methods of the first to third aspects of the present invention comprise a silsesquioxane compound having an oxetanyl group. And has a silsesquioxane structure to form a high hardness film. Therefore, the cationic photocurable composition obtained by the method of the present invention is suitably used as a cationic photocurable hard coat agent composition as in the fourth invention.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present specification, a compound having an oxetanyl group is referred to as an “oxetane compound”.

In the method for producing a cationic photocurable composition of the present invention, a silicon compound represented by the structural formula (I) is used as a raw material, and this compound is hydrolyzed in an atmosphere having a pH of 7 or more. . Here, the hydrolysis is performed at pH 7
When performed in the above atmosphere, when performed in an acidic atmosphere, the oxetanyl group is easily ring-opened, which may cause the system to gel, and the oxetanyl group is consumed and the curability of the composition is reduced. It is. This hydrolysis is pH 9 ~
It is preferably performed under an atmosphere of 13. When the pH is less than 9, the rate of hydrolysis and condensation of the silicon compound is low, so that the production efficiency of the composition of the present invention decreases. On the other hand, p
When H exceeds 13, the amount of the alkali agent and the like used increases, so that it is not economical, and the step of removing the alkali agent and the like from the reaction system becomes complicated.

R ⁰ in the above formula (I) is not particularly limited as long as it is an organic functional group having at least one oxetanyl group in a part thereof, and is a group represented by the structural formula shown in the above formula (II). Preferably, there is. In the formula (II), R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and it is particularly preferable that R ¹ is an ethyl group. Also,
R ² is an alkylene group having 2 to 6 carbon atoms, and particularly preferably, R ² is a propylene group. This is because it is easy to obtain or synthesize such an oxetane compound. When the composition obtained by this method is used as a photocationically curable hard coat agent composition, R
^{If the} number of carbon atoms of ¹ or R ² is 7 or more, the hardness of the film formed from this composition is liable to decrease, which is not preferable.

X in the above formula (I) is not particularly limited as long as it is a hydrolyzable group.
It is preferably a cycloalkoxy group or an aryloxy group. Further, one molecule of this compound contains three X's, and these may be all the same group or two or more different groups. As the other hydrolyzable group, a halogen atom can be mentioned. In this case, since the hydrogen halide is generated by the hydrolysis, the reaction system is likely to be in an acidic atmosphere, and thus the oxetanyl group may be opened.

The above "alkoxy group" includes, for example, methoxy group, ethoxy group, n- and i-propoxy group,
-, I- and t-butoxy groups. Also,
Examples of the “cycloalkoxy group” include a cyclohexyloxy group and the like, and examples of the “aryloxy group” include a phenyloxy group and the like. Among them, X is preferably an alkoxy group having 1 to 3 carbon atoms because the alkoxy group has good hydrolyzability. X is particularly preferably an ethoxy group because the raw materials are easily available and the hydrolysis reaction in the production of silsesquioxane is easily controlled.

In hydrolyzing the compound represented by the above formula (I), an alkali agent is usually added to the system in order to make the system have an atmosphere of pH 7 or more. As the alkaline agent, ammonia, quaternary ammonium salts, organic amines and the like can be used.
It is preferable to use a quaternary ammonium salt. Other reaction conditions at the time of hydrolysis are not particularly limited, but a preferable reaction temperature is 10 to 120 ° C (more preferably 20 to 80 ° C), and a preferable reaction time is 2 to 30 hours (more preferably 4 to 40 hours). 24 hours). The organic solvent used in the hydrolysis is not particularly limited, and examples thereof include alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran, toluene;
1,4-dioxane, hexane, ligroin and the like can be used. Among them, those capable of uniformly dissolving the reaction system are preferable.

The cationic photocurable composition obtained by the production method of the present invention may be any of ladder, basket and random as long as it is produced by hydrolysis of the compound represented by the above formula (I). May be composed of a silsesquioxane compound having the structure: This composition may contain only one kind of silsesquioxane compound, or may contain two or more kinds of silsesquioxane compounds having different structures or molecular weights.

In the silsesquioxane compound produced by hydrolysis, it is preferable that 90% or more of the number of hydrolyzable groups in the compound represented by the formula (I) is condensed. More preferably, substantially all of the groups are condensed. When the ratio of the remaining hydrolyzable groups exceeds 10%, the silsesquioxane structure is not sufficiently formed, so that the hardness of the film may decrease or the storage stability of the composition may decrease. Here, “substantially all of the hydrolyzable groups are condensed” means, for example, that NM of the obtained silsesquioxane compound
This can be confirmed by the fact that no peak based on the hydrolyzable group is observed in the R chart.

The silicone contained in the cationic photocurable composition
Lucesquioxane compounds have a number average molecular weight of 600
~ 5,000, preferably 1,000 ~ 3,
More preferably, 000. Number average molecular weight is 60
If it is less than 0, the film formed from this composition has
And sufficient hardness may not be obtained. In addition, the composition
Since the viscosity is low, this composition is
When used as a product, cissing is likely to occur on the coated surface
No. On the other hand, if the number average molecular weight exceeds 5,000, the composition
Is too high, making it difficult to handle.
When this composition is used as a hard cord composition,
In this case, the coatability decreases. In particular, this composition
When used as a docoat agent composition,
Number average of all silsesquioxane compounds
Silsesquioxane compound having a molecular weight of 1,000 to 3,000
Is preferably 50% by weight or more.
It is more preferable that the content be not less than% by weight. In this specification
Number average molecular weight in gel permeation
Minutes in terms of polystyrene by matography (GPC)
It is child quantity.

The silicon compound represented by the above formula (I) can be obtained, for example, by adding an oxetane compound having an alkenyl terminal to a compound represented by the following formula (III). Here, "the oxetane compound has an alkenyl terminal" means that the oxetane compound has a group selected from a vinyl group, an allyl group, an ethynyl group, a propargyl group, an isopropenyl group, and the like at its terminal. Among these, it is preferable that the alkenyl terminal is an allyl group because the raw materials can be easily obtained and synthesized, and the hydrosilylation reaction described later can be easily performed.

[0025]

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The addition reaction between the compound represented by the above formula (III) and the oxetane compound is a hydrosilylation reaction between the Si—H group of the compound represented by the above formula (III) and the alkenyl terminal of the oxetane compound. It proceeds in the presence of a Group 8 metal catalyst or the like. As the “Group 8 metal catalyst”,
A simple substance of a Group 8 metal such as cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum, an organic metal complex, a metal salt, and a metal oxide are exemplified. Among them, a platinum metal simple substance, an organometallic complex, a metal salt and a metal oxide are preferable, because the catalyst activity is appropriate and the handling is easy, and it is relatively inexpensive. It is particularly preferable to use an organic platinum complex.
This catalyst is preferably used in an amount of 1 to 1,000 ppm by weight based on the total amount of the compound represented by the formula (III) and the oxetane compound. Other reaction conditions in the hydrosilylation reaction are not particularly limited, but a preferable reaction temperature is 20 to 100 ° C, and a preferable reaction time is 2 to 100 ° C.
10 hours.

The cationic photocurable composition or the cationic photocurable hard coat composition produced by the method of the present invention is obtained by subjecting the silsesquioxane compound obtained by hydrolysis of the compound represented by the above formula (I) to In addition, general additives such as a photoinitiator, a viscosity modifier, a leveling agent, a stabilizer, and a silane coupling agent can be included. Further, the composition may contain an organic solvent, but the content is preferably 20% by weight or less based on the whole composition, and
More preferably, it is 0% by weight or less.

[0028]

EXAMPLES The present invention will be described more specifically with reference to the following examples.

(1) Synthesis of Photo-Cation-Curable Composition The photo-cation-curable compositions of Examples 1 to 10 were obtained by hydrolyzing a silicon compound represented by the following formula (IV). This silicon compound is an addition reaction product of 3-ethyl-3-allyloxymethyloxetane and triethoxysilane. Hereinafter, the silicon compound represented by the formula (IV) is referred to as “Oxe-TRIES”.

[0030]

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Example 1 (1) Ox was added to a reactor equipped with a stirrer, thermometer and cooler.
12.37 g (38.6 mmol) of e-TRIES, tetramethylammonium hydroxide (hereinafter, “Me ₄ NO
H ") (1.05 g of a 10% aqueous solution (H ₂ O; 5
2.5 mmol, Me ₄ NOH; 1.2 mmol), 1.14 g (63.3 mmol) of water and 1, as a solvent
300 ml of 4-dioxane was charged, and 16
Heated to reflux for hours. At this time, the pH of the reaction system was 12.
It was one. (2) The reaction system was concentrated by distilling off 200 ml of the solvent.
The reaction was continued for hours. (3) After completion of the reaction, the solvent and the like were distilled off under reduced pressure, and 200 ml
The solvent was replaced with toluene. (4) After washing with water several times with a separating funnel and dehydrating with anhydrous sodium sulfate, toluene was distilled off under reduced pressure to obtain a desired composition A-1.

The obtained composition A-1 is highly viscous,
It was soluble in various solvents such as toluene, tetrahydrofuran, hexane and acetone at an arbitrary ratio. GPC measurement was performed on this composition A-1 under the following conditions. [Measurement conditions] Apparatus; HLC-802A (manufactured by Tosoh Corporation) Column; TSK-GEL, 2500HXL + 1000HXL eluent; tetrahydrofuran (flow rate: 1.0 ml / min) Detector; RI

As shown in FIG. 1, the obtained GPC chart was almost monomodal, although a slight shoulder was observed on the high molecular weight side. The molecular weight of composition A-1 determined from the GPC measurement results was as follows. Number average molecular weight (Mn); 1,870 Weight average molecular weight (Mw); 2,450 Dispersity (Mn / Mw); 1.31 This monomodal peak is a cage structure which is an octamer of Oxe-TRIES. It is inferred to be silsesquioxane (T8). In addition, the shoulder seen on the high molecular weight side is presumed to be a random structure, a ladder structure, a cage structure silsesquioxane of 10-mer or more, or a mixture thereof.

The IR chart of the composition A-1 is shown in FIG.
Shown in Here, absorption based on the cyclic ether bond is observed at 981.4 cm ⁻¹ , indicating that the composition A-1 is composed of a compound having an oxetanyl group. 111
The absorption at 0.8 cm ⁻¹ is due to the Si—O—Si bond and CH ₂
It is based on -O-CH ₂ bond.

FIG. 3 shows the ¹ H-NMR chart of the composition A-1. The peak at 4.3 to 4.5 ppm indicates a hydrogen atom of CH _{2 in} the oxetane ring. In addition, this NMR
Since the peak corresponding to the hydrogen atom of ethoxy groups _{(Si-O-C 2 H} 5) was observed in the chart,
The hydrolysis reaction proceeds favorably, and it is presumed that substantially all of the hydrolyzable groups of Oxe-TRIES are condensed. The simultaneous observation of a broad peak and a sharp peak in this NMR chart indicates that the composition A-1 is a mixture of various silsesquioxane compounds having different structures. Among these, it is considered that the sharp peak is derived from the silsesquioxane compound having a cage structure, and the broad peak is derived from the silsesquioxane compound having a ladder structure or a random structure.

(Examples 2 to 8) Oxe-T was placed in a reactor.
4.12 g (12.9 mmol) of RIES, Me ₄ NO
0.35 g of a 10% aqueous solution of H (H ₂ O; 17.5 mmol
1, Me ₄ NOH; 0.4 mmol), 0.38 g of water
(21.1 mmol) and 100 ml of the solvent shown in Table 1 were charged, and the reaction was allowed to proceed by stirring at room temperature for 24 hours. The pH of the reaction system at the end of the reaction
Was in the range of 11.8 to 12.5. After completion of the reaction, the same treatment as in Example 1 was carried out, to give composition A-2.
To A-8 were obtained.

GPC measurement was carried out on the obtained compositions A-2 to A-8 in the same manner as in the composition A-1. GP obtained
C charts are shown in FIGS. 4 to 10, and Table 1 shows the molecular weight and the appearance of the composition determined by GPC measurement. In Table 1, “MeOH” represents methyl alcohol, “EtOH” represents ethyl alcohol, “IPA” represents isopropyl alcohol, “MEK” represents methyl ethyl ketone, and “THF”.
Represents tetrahydrofuran. “Peak 5” is the remaining Oxe-TRIES.

[0038]

[Table 1]

As can be seen from Table 1, in Example 2 in which methyl alcohol was used as the solvent, the GPC chart was bimodal, and more high molecular weight compounds were produced than in Example 1. In Examples 3 to 6, the compounds contained in the obtained compositions were almost the same, but when alcohols were used as solvents, the coloring of the compositions was higher than when ketones were used. Tended to decrease. This is considered to be because Me ₄ NOH can stably exist in alcohol. Example 7 using tetrahydrofuran
In Example 8 using toluene and toluene, unreacted Oxe-
TRIES remained considerably. The reason may be that Me ₄ NOH is hardly soluble in tetrahydrofuran and that water is not soluble in toluene.

(Example 9) In Example 2, the hydrolysis was carried out at room temperature. The reaction temperature was the reflux temperature of the solvent, and the composition A- 9 was synthesized. That is, Oxe-TR is placed in the reactor.
IES 38.6 mmol, Me ₄ NOH 1.2 mmol
l, 115.8 mmol of H ₂ O, and 300 ml of methyl alcohol were charged and the reaction was allowed to proceed by stirring at a reflux temperature for 24 hours. The reaction solution was treated in the same manner as in Example 1 to obtain a composition A-9. The pH of the reaction system at the end of the reaction was 12.0. The GPC chart of the obtained composition A-9 is shown in FIG. 11, and the molecular weight and the appearance of the composition obtained from GPC measurement are shown in Table 2.

Example 10 Oxe during hydrolysis
-Composition A-10 was synthesized under the same conditions as Example 9 except for increasing the concentration of TRIES. That is, 193.0 mmol of Oxe-TRIES, Me ₄ NO
Resulting H6.0mmol, H ₂ O579.0mmol, and g of methyl alcohol 300 ml, the reaction is allowed to proceed by stirring for 24 hours at reflux temperature, the composition A-10 was treated in the same manner as in Example 1 and the reaction mixture Was. The pH of the reaction system at the end of the reaction was 12.0. FIG. 11 shows a GPC chart of the obtained composition A-10.
Table 2 shows the molecular weight and the appearance of the composition determined from the measurement.

[0042]

[Table 2]

Comparison of FIGS. 3, 11 and 12 and Table 2
As can be seen from the graph, when the reaction temperature was low, the generation ratio of low molecular weight compounds tended to increase. This is probably because depolymerization is suppressed at low temperatures. Also, Oxe
When the concentration of -TRIES is high, the molecular weight tends to increase. This is considered to be because condensation is likely to occur and a silsesquioxane compound having a ladder structure or a random structure is likely to be generated.

(2) Evaluation of photo-cationic curable composition Photo-cationic curable composition A-
1 to A-10 were dissolved in a small amount of hexane, and 2.5 wt% of a cationic photoinitiator was added based on the weight of the cationic photocurable composition. The composition was applied on a glass substrate with a bar coater, and after the solvent was distilled off, the composition was irradiated with ultraviolet light under the following conditions. As a result, all the compositions showed good cationic photocurability. [UV irradiation conditions] Lamp: 80 W / cm high-pressure mercury lamp Lamp height: 10 cm Conveyor speed: 10 m / min Irradiation atmosphere: in the atmosphere Pass number: 5 times Initiator: bis (dodecylphenyl) iodonium hexafluoroantimonate (2. (Use 5wt%)

Among them, the pencil hardness of the surface of the cured film formed from the composition of Example 1 was measured according to JIS K5400. As a result, it was found that the coating film had a high hardness of 5H for flaws and 9H or more for peeling.

The present invention is not limited to the specific embodiments described above, but may be variously modified within the scope of the present invention in accordance with the purpose and application.

[0047]

According to the production method of the present invention, a cationic photocurable composition comprising a silsesquioxane compound having an oxetanyl group can be easily obtained. Since this silsesquioxane compound has an oxetanyl group having a high photocationic polymerization rate, it is excellent in photocationic polymerizability as compared with an epoxide type monomer. Since the composition obtained by the production method of the present invention is soluble in various organic solvents, it is easier to handle as compared with silica, and is excellent in processability such as film formation and moldability. Further, since a photocationic cured product having high hardness can be formed, it is useful as, for example, a hard coat agent composition.

[Brief description of the drawings]

FIG. 1 is a GPC chart of a cationic photocurable composition A-1 produced according to Example 1.

FIG. 2 is an IR chart of the cationic photocurable composition A-1 produced in Example 1.

FIG. 3 is a ¹ H-NMR chart of a cationic photocurable composition A-1 produced according to Example 1.

FIG. 4 is a GPC chart of a cationic photocurable composition A-2 produced according to Example 2.

FIG. 5 is a GPC chart of a cationic photocurable composition A-3 produced according to Example 3.

FIG. 6 is a GPC chart of a cationic photocurable composition A-4 produced according to Example 4.

FIG. 7 is a GPC chart of a cationic photocurable composition A-5 produced according to Example 5.

FIG. 8 is a GPC chart of a cationic photocurable composition A-6 produced according to Example 6.

FIG. 9 is a GPC chart of a cationic photocurable composition A-7 produced according to Example 7.

FIG. 10 is a GPC chart of a cationic photocurable composition A-8 produced according to Example 8.

FIG. 11 is a GPC chart of a cationic photocurable composition A-9 produced according to Example 9.

FIG. 12 is a GPC chart of a cationic photocurable composition A-10 produced according to Example 10.

Claims (4)

[Claims] 1. A method for producing a cationic photocurable composition comprising a silsesquioxane compound having an oxetanyl group, comprising the steps of: reacting a compound represented by the following structural formula (I) with an atmosphere having a pH of 7 or more: A method for producing a photocationically curable composition, comprising hydrolyzing. Embedded image (2) R ⁰ in the above formula (I) is the following formula (I)
The method for producing a cationic photocurable composition according to claim 1, wherein the composition is an organic functional group represented by the structural formula shown in (I). Embedded image 3. The method for producing a cationically photocurable composition according to claim 1, wherein X in the formula (I) is an alkoxy group, a cycloalkoxy group or an aryloxy group. 4. A cationically photocurable hard coat composition comprising the cationically photocurable composition obtained by the production method according to claim 1. Description: