JP2002226709A - Photocationically polymerizable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocationically polymerizable composition having a high optical transmittance and a high reactivity, even when formulated with a whitening agent (a filler for whitening). SOLUTION: This photocationically polymerizable composition comprises cationically polymerizable substances. The haze value of the composition is >=60% and the UV transmittance is >=30% at 365 nm when measured on a 100 μm thick film thereof. Preferably the composition comprises 0.02-20 pts.wt. of a photocationic catalyst and 2-50 pts.wt. of a whitening agent per 100 pts.wt. of the total cationically polymerizable substances, wherein the refractive index of the whitening agent is 1.4-2.0, and the particle size of the whitening agent is 0.1-400 μm. More preferably, the composition is photosensitive to light having wave length components in a 300-800 nm range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cationic photopolymerizable composition which is cured by irradiation with light in the presence of a cationic photocatalyst. More specifically, the present invention relates to a cationic photopolymerizable composition used for a whitened adhesive or the like.

[0002]

2. Description of the Related Art Hitherto, as a photocationic catalyst for curing a cationically polymerizable substance by irradiating light, triphenylphenacylphosphonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate have been known. And the like (for example, JP-A-61-174221). As the cationic polymerizable substance, for example, an epoxy compound, a vinyl ether compound, oxetane, or the like is used, and is used for photocuring.

[0003] Such a curing reaction is industrially required for paints,
Coating, varnish, composite matrix, stereolithography,
While being widely used in the fields of adhesives, pressure-sensitive adhesives, and the like, various studies have been made on the demands of further markets. In particular, in recent years, for an adhesive or the like used for a material having a transparent base material such as an IC card (for example, PET resin), an adhesive having a white color (whitened adhesive) has been required. The reason is as follows. That is, a material having a transparent base material such as an IC card is usually printed with various characters or patterns on its surface and used by bonding to other materials such as an IC module, but in this case, it is not printed. In the transparent portion, other materials can be seen through, so that the appearance deteriorates. In order to prevent this, it is required that the adhesive itself is white (whitening of the adhesive).

[0004] However, conventionally, there has been a problem that when light-curing adhesives and the like are to be whitened, the light transmittance is reduced and the curing reaction is significantly reduced. That is, for example, in the case of an adhesive or the like using a cationically polymerizable substance, if a whitening agent (filler for whitening) is blended, there is a problem that the light transmittance is reduced and the curing reaction is inhibited. Was. Therefore, it has been desired to solve the above-mentioned problems and to develop a cationic photopolymerizable composition which does not inhibit the curing reaction even with a whitened adhesive or the like.

[0005]

In view of the above, it is an object of the present invention to provide a photocationically polymerizable composition, more specifically, a composition containing a cationically polymerizable substance, and a whitening agent (for whitening). The present invention is to provide a photocationically polymerizable composition having high light transmittance and high reactivity even if the composition contains a filler).

[0006]

The cationic photopolymerizable composition according to claim 1 is a cationic photopolymerizable composition comprising a cationic polymerizable substance and a whitening agent, and having a thickness of 10%.
The haze value when formed into a film of 0 μm is 60% or more, and the ultraviolet ray transmittance at 365 nm is 30% or more. The cationic photopolymerizable composition according to claim 2 contains 0.02 to 20 parts by weight of a photocationic catalyst and 2 to 50 parts by weight of a whitening agent, based on 100 parts by weight of the total amount of the cationically polymerizable substance. A photocationically polymerizable composition comprising: a whitening agent having a refractive index of 1.4 to 2.0, and a particle size of the whitening agent of 0.1 to 400 μm. 3. The cationic photopolymerizable composition according to claim 1, wherein the photocationic polymerizable composition according to claim 3 is exposed to light containing a wavelength component of 300 to 800 nm.

Hereinafter, the present invention will be described in detail. The cationically polymerizable substance in the present invention is not particularly limited as long as it causes a curing reaction by a photocationic catalyst.For example, bisphenol-epoxy resin, phenolic epoxy resin, halogenated phenol epoxy resin, polyalkylene glycol epoxy resin, Butyl glycidyl ether, epoxy compounds such as phenyl glycidyl ether, isopropyl vinyl ether, vinyl ether compounds such as cetyl vinyl ether, oxetane,
Examples thereof include polyester resins, which may be used alone or in combination of two or more.

[0008] As the photocationic catalyst in the present invention,
The catalyst is not particularly limited as long as it generates a cationic species by light, but usually, an onium salt or the like is preferably used. Examples of the onium salt include a diazonium salt of a Lewis acid, an iodonium salt of a Lewis acid, a sulfonium salt of a Lewis acid, and the like. Examples of these catalysts include phenyldiazonium salt of boron tetrafluoride, diphenyliodonium salt of phosphorus hexafluoride, diphenyliodonium salt of antimony hexafluoride, and tri-4-methylphenylsulfonium salt of arsenic hexafluoride And tri-4-methylphenylsulfonium salt of antimony tetrafluoride. Commercially available products include, for example, Irgacure 2
61 (manufactured by Ciba-Geigy), Optmer SP-150,
Optomer SP-151, Optomer SP-170, Optomer SP-171 (manufactured by Asahi Denka Kogyo), UVE-1
014 (manufactured by General Electric), CD-101
2 (manufactured by Sartomer), Sun Aid SI-60L, Sun Aid SI-80L, Sun Aid SI-100L (manufactured by Sanshin Chemical Industry), CI-2064, CI-2639, C
I-2624, CI-2481 (Nippon Soda Co., Ltd.), RH
ODORSIL PHOTOINITIATOR207
4 (manufactured by Rhone Poulin), UVI-6990 (manufactured by Union Carbide), BBI-103, MPI-10
3, TPS-103, MDS-103, DTS-10
3, NAT-103, NDS-103 (manufactured by Midori Kagaku) and the like.

The compounding ratio of the photocationic catalyst according to the present invention is preferably 0.02 to 20 parts by weight based on 100 parts by weight of the total amount of the cationically polymerizable substance. If the amount is less than 0.02 parts by weight, a sufficient reaction does not occur, and if the amount exceeds 20 parts by weight, it is difficult to achieve both a usable time (a usable time after light irradiation) and a curing speed. More preferably, 0.1 to 1
0 parts by weight.

The whitening agent used in the present invention is not particularly limited as long as it exerts the effects of the present invention. Examples thereof include calcium carbonate, aluminum oxide, aluminum hydroxide, barium sulfate, magnesium oxide, glass balloon and the like. Is mentioned. Further, it is more preferable that the whitening agent has a refractive index of from 1.4 to 2.0 and a particle size of from 0.1 to 400 µm, since light transmittance is improved. These may be used alone or in combination of two or more. The mixing ratio of the whitening agent according to the present invention is preferably 2 to 50 parts by weight based on 100 parts by weight of the total amount of the cationically polymerizable substance. If the amount is less than 2 parts by weight, sufficient whitening cannot be obtained, and if the amount exceeds 50 parts by weight, the physical properties of the cured product are affected.

The cationic photopolymerizable composition of the present invention is preferably further exposed to light containing a wavelength component of 300 to 800 nm. When exposed to light containing only a wavelength component of less than 300 nm, when the composition is applied thickly, skinning tends to occur on the light-irradiated surface, and a problem that the composition is not uniformly cured from the surface layer to the deep portion easily occurs. On the other hand, 8
When exposed to light containing only wavelength components exceeding 00 nm,
Although skinning does not easily occur and hardens evenly over the deep part,
It becomes difficult to provide sufficient light energy, and a sufficient curing speed cannot be expected.

In the present invention, as a light source lamp used for light irradiation, a lamp having a distribution of light wavelengths of 300 to 800 nm is usually preferably used. For example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp chemical Lamps, black light lamps, microwave excited mercury lamps, metal halide lamps, sodium lamps, fluorescent lamps and the like. In this case, in order to prevent curing of only the surface layer of the composition of the present invention and realize internal curing, it is also possible to cut and irradiate light of 300 nm or less.

Further, the viscosity of the cationic photopolymerizable composition of the present invention is not particularly limited, but is 0 ° C to 40 ° C.
1 cps to 100000 at any temperature in the range
It is preferably 0 cps. When the viscosity is less than 1 cps, the fluidity becomes too high, and it is easy to flow to a place where coating should not be performed, resulting in poor workability. On the other hand, when the viscosity exceeds 1,000,000 cps, the fluidity is remarkably reduced and the coating operation becomes difficult.

In the cationic photopolymerizable composition of the present invention, in addition to the above, a known tackifying resin, a thickener, a bulking agent, a regulator and the like are appropriately compounded within a range not to impair the object of the present invention. Is also good. Examples of the tackifying resin include a rosin resin, a modified rosin resin, a terpene resin, a terpene phenol resin, an aromatic modified terpene resin, a C5 or C9 petroleum resin, a cumarone resin, and the like. Examples of the thickener include acrylic rubber, epichlorohydrin rubber, isoprene rubber, butyl rubber and the like. As the extender, for example, colloidal silica,
Examples include thixotropic agents such as polyvinylpyrrolidone, clays, and the like. Examples of modifiers include acrylic polymers, polyesters, polyurethanes, silicones, polyvinyl ethers, polyvinyl chloride, polyvinyl acetate, polyisobutylene, and waxes.

(Function) The cationic photopolymerizable composition of the present invention has a haze value of 60% or more when formed into a film having a thickness of 100 μm and transmits ultraviolet light having a wavelength of 365 nm when formed into a film having a thickness of 100 μm. It has been found that, when the composition has a ratio of 30% or more, both photoreactivity of the composition and whitening when formed into a film are compatible. This is realized by a combination of a whitening agent and a cationic polymerizable substance. For example, the refractive index of the whitening agent is 1.4 to 2.0, and the particle size of the whitening agent is 0.1. It is realized by having a thickness of 1 to 400 μm. The mechanism of action is not clear, but depending on the refractive index difference between the whitening agent and the cationically polymerizable substance and the conditions such as the particle size of the whitening agent, light transmission (contributing to curing reactivity) and scattering are caused. It is presumed that the property (contributing to whitening) is optimized.

[0016]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. (Example 1) In a sample bottle of about 200 mL, 80 g of Elitel UE3400 (polyester resin: manufactured by Unitika) as a cationically polymerizable substance, Epicoat 828
20 g of an epoxy resin (manufactured by Yuka Shell Epoxy), 2 g of UVI-6990 (manufactured by Union Carbide) as a photocationic catalyst, and 10 g of calcium carbonate (manufactured by Wako Pure Chemical Industries) as a whitening agent were mixed by heating (100 ° C., 2 ° C.). Time)
A photocationically polymerizable composition was obtained. The refractive index and the particle size of the whitening agent are shown in Table 1 together with other examples and comparative examples.

Example 2 A cationic photopolymerizable composition was obtained in the same manner as in Example 1 except that aluminum oxide (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a whitening agent. (Example 3) Except that magnesium oxide (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a whitening agent, the same as in Example 1,
A photocationically polymerizable composition was obtained.

Comparative Example 1 A cationic photopolymerizable composition was obtained in the same manner as in Example 1 except that titanium oxide (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a whitening agent. (Comparative Example 2) Zinc oxide (manufactured by Wako Pure Chemical Industries, Ltd.) as a whitening agent
A photocationically polymerizable composition was obtained in the same manner as in Example 1 except for using.

(Evaluation Method) Using the obtained cationic photopolymerizable composition, a film having a thickness of 100 μm was prepared, and the ultraviolet transmittance and the haze value (according to JIS K7105) were measured. The resulting cationic photopolymerizable composition was irradiated with ultraviolet rays (intensity at a wavelength of 365 nm was 1500 mJ / c).
m ² ), the epoxy reaction rate (epoxy conversion) after curing was measured by the following method. The measurement of the epoxy reaction rate was determined from the epoxy equivalent of the sample before irradiation with ultraviolet light and the sample after irradiation. The measurement method and calculation formula are shown below. The UV intensity was measured using Topcon's UVR-1 and UVR-36.

Measurement method 1) Add a predetermined amount of hydrochloric acid: dioxane (8: 500) to a sample and mix 2) Add a predetermined amount of ethanol 3) Add a few drops of neutral cresol red aqueous solution 4) N / 10-ethanol KOH solution Formula: Epoxy equivalent = 36.46 / HClabs × 1000 HClabs = (BT-ST) × 3.646 / S BT = Titration of N / 10-ethanol KOH solution required for blank test Amount ST = titration amount of N / 10-ethanol KOH solution required for this test S = sampled amount Epoxy conversion (epoxy conversion) = (1- (epoxy equivalent (before irradiation) / epoxy equivalent (after irradiation)) × 100 The evaluation results are shown in Table 1.

[0021]

[Table 1] According to Table 1, in the cationic photopolymerizable composition of the present invention, the composition is sufficiently whitened (hazard value is 60% or more), has high ultraviolet transmittance, and has sufficient curing reactivity (epoxy reactivity). It can be seen that it can be obtained.

[0022]

According to the photocationically polymerizable composition of the present invention, it has been found that the reactivity and the whitening when formed into a film are practically compatible. That is, by setting the composition so that the haze value and the ultraviolet transmittance when formed into a film are in the optimum ranges, it is possible to achieve both the photoreactivity of the composition and whitening when formed into a film. became. Further, the composition of the present invention according to claim 2, wherein the blending of the photocationic catalyst and the whitening agent is limited, and the refractive index and the particle size of the whitening agent are limited, can achieve the above effects more reliably. Industrially, the present invention can be widely used when whitening is required for the composition applied in the fields of paints, coatings, varnishes, composite matrices, stereolithography, adhesives, adhesives, and the like. Especially for IC cards,
For adhesives and the like used for materials whose base material is transparent (for example, PET resin, etc.), even when a whitening agent is blended, a photocationically polymerizable composition having high light transmittance when formed into a film is provided. And the characteristics can be maximized.

Continued from the front page F-term (reference) 4J002 BE041 CD011 CD051 CD071 CD121 CF001 CH031 DE076 DE146 DE236 DG046 DK007 DL006 EB117 EQ017 EV297 FA106 FD096 FD157 FD207 GJ01 4J040 EC021 EC061 EC261 ED001 HA136 HA196 HA256 HA346 HB43 KA05 J35

Claims (3)

[Claims] 1. A photocationically polymerizable composition comprising a cationically polymerizable substance and a whitening agent, the composition having a thickness of 100 μm.
A cationic photopolymerizable composition, which has a haze value of 60% or more and a UV transmittance at 365 nm of 30% or more when formed into a film of m. 2. A photo-cationic catalyst is used in an amount of 0.02 to 20 parts by weight based on 100 parts by weight of the total amount of the cationic polymerizable substance.
A photocationically polymerizable composition containing 2 to 50 parts by weight of a whitening agent, wherein the refractive index of the whitening agent is 1.4 to 2.0.
The cationic photopolymerizable composition according to claim 1, wherein the whitening agent has a particle size of 0.1 to 400 µm. 3. The cationic photopolymerizable composition according to claim 1, which is sensitized by light containing a wavelength component of 300 to 800 nm.