JPH0426333B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention relates to a method for curing an ultraviolet curable resin composition comprising, for example, an epoxy resin and a cationic polymerization catalyst, and in particular, a method for curing an ultraviolet curable resin composition comprising, for example, an epoxy resin and a cationic polymerization catalyst. The present invention relates to a method for curing a UV curable resin composition. [Prior art and its problems] Cationic polymerization type photocurable resin compositions such as epoxy resin compositions are polymerized and cured by irradiation with light energy such as ultraviolet rays, so they are processed into a desired shape by casting or coated. is applied to the desired construction area, and then irradiated with ultraviolet energy,
After oxidation treatment, it is widely used for various molded products, coatings, adhesives, sealants, etc. Conventionally, in the curing treatment of this type of composition, for example, when manufacturing a molded article, the composition is cast into a mold and processed into a desired shape, and then irradiated with ultraviolet energy. In addition, when obtaining a film, the composition is applied to the desired construction site using a coating machine, and then this coating film is cured by irradiating ultraviolet energy to obtain an adhesive sealant. In this case, the composition is poured into the desired construction area (grooves, etc.) from the discharge port of the dispensing machine and overlaid, and the same as described above is applied to this overlay.
It was cured by irradiating it with ultraviolet light. However, in all of the above-mentioned curing methods, the composition is cast into the desired shape or applied to the desired area and then irradiated with ultraviolet energy, so it is difficult for the cast product to have a complex shape. If there is a part that cannot be irradiated with ultraviolet energy, the composition in that part will not be cured, and if the applied part is a hidden place that cannot be irradiated with ultraviolet energy, the composition in that part will not be cured. The material was not cured and therefore the above-mentioned curing method was not applicable in either of these cases. [Object of the Invention] The object of the present invention is to cure cast products with complex shapes that cannot be irradiated with ultraviolet energy and that can be cured without undergoing curing treatment by irradiation with ultraviolet energy after casting or coating. It cures easily even if the coating is in a hidden location where it cannot be exposed to UV energy.
The object of the present invention is to provide a method for curing an ultraviolet curable resin composition, which improves the drawbacks of the above-mentioned known techniques. [Summary of the Invention] In order to achieve the above-mentioned object, according to the present invention,
When polymerizing and curing an ultraviolet curable resin composition by irradiating it with ultraviolet energy, the composition is uniformly irradiated with ultraviolet energy at a stage prior to the casting or coating process for applying the composition to the desired use. It is characterized in that the polymerization reaction is induced in advance by irradiation without any radiation. [Embodiments of the Invention] The present invention will be described below with reference to FIG. 1st
The figure is a block diagram of an apparatus for carrying out the method of the present invention.
Reference numeral 1 is a quartz tube or glass tube filled with ultraviolet curable resin composition A, which has a discharge port 2 at its tip, and a portion on the way to the discharge port 2 is a thin tube 1a, which will be described later. Composition A is irradiated with ultraviolet energy as follows. At the time of irradiation, it is preferable that the quartz tube or the glass tube be a thin tube 1a, since the composition A can be easily irradiated evenly over the entire area with ultraviolet energy. Also,
An ultraviolet lamp 3 is arranged on one side of the thin tube 1a, and an aluminum reflector 4 is placed so as to surround this ultraviolet lamp 3, and an aluminum reflector 4 is placed on the other side of the thin tube 1a, facing the ultraviolet lamp 3. An aluminum reflector plate 5 is also placed at the position where the ultraviolet lamp 3
The structure is such that the ultraviolet energy from the tube is efficiently irradiated onto the thin tube 1a. When the resin composition A is passed through the quartz tube or glass tube 1 using the above-mentioned device, the composition A is poured into a desired shape before being discharged from the discharge port 2. Before it is molded or applied to the desired construction site, it is uniformly and easily irradiated with ultraviolet energy to induce a polymerization reaction, but when it is discharged from the discharge port 2, it is still in a liquid state. It is then cast into the desired shape or applied to the desired application site, and then cured by propagation polymerization without irradiation with ultraviolet energy. As mentioned above, the present invention does not require polymerization curing treatment by irradiation with ultraviolet energy after casting or coating as in the past, and therefore cast products with complex shapes that cannot be irradiated with ultraviolet energy. It cures easily even if the coating is in a hidden location where it cannot be exposed to ultraviolet energy. The resin used in the present invention is an epoxy resin. Examples of this include conventionally known aromatic epoxy resins, cycloaliphatic epoxy resins, aliphatic epoxy resins, and the like. Here, particularly preferable aromatic epoxy resins are polyglycidyl ethers of polyvalent phenols having at least one aromatic nucleus or their alkylene oxide adducts, such as bisphenol A or its alkylene oxide adducts. Examples include glycidyl ethers and epoxy novolac resins produced by reaction with epichlorohydridine. Particularly preferable cycloaliphatic epoxy resins include polyglycidyl ethers of polyhydric alcohols having at least one alicyclic ring, or compounds containing cyclohexene or cyclopentene rings, which are epoxidized with a suitable oxidizing agent such as hydrogen peroxide or peracetic acid. cyclohexene oxide or cyclopentene oxide containing compounds. Typical examples of polyglycidyl ethers include glycidyl ethers produced by reacting hydrogenated bisphenol A or its alkylene oxide adduct with epichlorohydrin. Furthermore, representative examples of cyclohexene oxide or cyclopentene oxide-containing compounds include those represented by the following formula. Particularly preferable aliphatic epoxy resins are aliphatic polyhydric alcohols or their alkylene oxide adducts, polyglycidyl ethers, representative examples of which are diglycidyl ether of 1,4-butanediol and 1,6-hexane. 1 for aliphatic polyhydric alcohols such as diglycidyl ether of diol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, ethylene glycol, propylene glycol, and glycerin. Examples include polyglycidyl ethers of polyether polyols obtained by adding a species or two or more alkylene oxides (ethylene oxide, propylene oxide). Furthermore, monoglycidyl ethers of aliphatic higher alcohols, phenol, cresol, butylphenol, or monoglycidyl ethers of polyether alcohols obtained by adding alkylene oxide to these may also be blended as diluents. As the epoxy resin used in the present invention, these aromatic epoxy resins, cycloaliphatic epoxy resins, or aliphatic epoxy resins can be used alone, but it is desirable to blend them appropriately depending on the desired performance. The cationic polymerization catalyst used in the present invention is a group of double salts, which are onium salts that release Lewis acids capable of initiating polymerization upon irradiation. Such compounds basically have the general formula [R ¹ aR ² bR ³ cR ⁴ dZ]
^+m [MX _o+n ] ^-m [In the formula, the cation is onium, Z is N≡N, S, Se, Te, P, As, Sb,
Bi, O, halogen (for example, I, Br, Cl), and R ¹ , R ² , R ³ and R ⁴ are organic groups which may be the same or different. a, b, c, d are each 0~
A+b+c+d is an integer of 3 and is equal to the valence of Z. M is a metal or metalloid that is the central atom of the halide complex, B, P,
As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn,
These include So, V, Cr, Mn, Co, etc. X is a halogen, m is the net charge of the halide complex ion, and n is the number of halogen atoms in the halide complex ion. ]. Specifically, triarylsulfonium salts or diaryliodonium salts are often used as this type of cationic polymerization catalyst. These are substances that can decompose under ultraviolet irradiation and cause polymerization or crosslinking of epoxy resins; A compound having the formula, where M is Sb, P,
As, etc., X is a halogen element, n is an integer that can vary depending on M, for example,
When X is F in Sb, n is 6. Also, the latter is a general formula , where M, X, and n are the same as the former. Example 1 The following formulation was prepared as an ultraviolet curable epoxy resin composition. Compound 1 *1 Epicote 828 100 (parts by weight) *3 UVE-1014 0.1 (〃) Compound 2 *1 Epicote 828 100 (parts by weight) *2 KBM202 4 (〃) *3 UVE-1014 0.1 (〃) * (1) Bisphenol A type epoxy resin (manufactured by Schiel Chemical) *(2) Diphenyldimethoxysilane (manufactured by Shin-Etsu Chemical) *(3) 50% solution of triarylsulfonium salt in propylene carbonate (manufactured by GE) Above Mixtures 1 and 2 were placed in quartz tube 1 in Figure 1, respectively.
(The diameter of the thin tube 1a is 1 mm, and the thickness of the quartz tube wall is 0.3 mm).
Uses a lamp with an output of 300W. ) for 10 seconds with an energy amount of approximately 40 mW/cm ² , and then discharged from the discharge port 2 into a 20 mm x 10 mm polyethylene container and left in a dark place at room temperature to harden. The situation was observed and the results shown in Table 1 were obtained. The energy amount was measured using an ultraviolet luminometer M-01 manufactured by Oak Seisakusho Co., Ltd. and a UV-25 sensor. This amount of energy was determined by adjusting the discharge speed.

[Table] For comparison, the formulation with the same energy content is 60
After 24 hours of irradiation and complete hardening, the hardness was measured, and the hardness was 74 for No. 1 and 77 for No. 2. Therefore, the resin discharged by the above method is considered to be completely cured after 24 hours. Example 2 An experiment was conducted in the same manner as in Example 1, except that the discharge speed was adjusted so that the irradiation was performed for 15 seconds, and the results shown in Table 2 were obtained.

[Table] In this case, the open time after discharge was even shorter, but the final hardness was almost the same as in Example 1, and the hardness was perfect. Example 3 Using formulation No. 2 of Example 1, it was poured into the mold in the same manner as in Example 1, except that the polyethylene container of Example 1 was replaced with a mold (released). did. After 30 minutes, the mold was removed to obtain a cured product. As a comparative example, the same compound was injected into a mold and then irradiated with ultraviolet rays of the same intensity from the injection port for 5 minutes according to the conventional curing method. After 30 minutes, the mold was removed and the cured product was observed. In the case of the former example, the obtained cured product had the perfect shape as the mold, but in the case of the latter comparative example, only the part exposed to ultraviolet rays was cured, leaving the part that was in the shadow. was almost uncured. Example 4 The following formulation was prepared as an ultraviolet curable epoxy resin composition, and its effectiveness as an adhesive was investigated. *(7) ER-200C 20 parts by weight *(8) Epikote #815 80 The above formulation was irradiated with ultraviolet energy in the same manner as in Example 1, and then discharged onto three pieces of iron and three lauan test pieces. The samples were stacked and left for the various times shown in Table 3. Thereafter, a tensile shear test was conducted on each sample, and the results are shown in Table 3. *(7) Ultraviolet curable epoxy resin compound (manufactured by Asahi Denka Kogyo Co., Ltd.) *(8) Bisphenol A type epoxy resin (manufactured by Ciel Chemical Co., Ltd.)

〔Effect of the invention〕

As described above, according to the curing treatment method of the present invention, the composition is uniformly irradiated with ultraviolet energy before the casting or coating process, and unlike the conventional method, the composition is irradiated with ultraviolet energy evenly before the casting or coating process. Because the polymerization curing process using energy irradiation is omitted, it is possible to coat cast products with complex shapes that cannot be exposed to UV energy irradiation, or in hidden places that cannot be exposed to UV energy irradiation. It can be easily cured even if it is.

[Brief explanation of drawings]

FIG. 1 shows a specific configuration diagram of an apparatus for carrying out the method of the present invention. 1...Quartz tube glass tube, 2...Discharge port, 3...
Ultraviolet lamp, 4, 5... Reflection plate, 1a... Capillary tube, A... Resin composition.

Claims (1)

[Scope of Claims] 1. When polymerizing and curing an ultraviolet curable resin composition by irradiation with ultraviolet energy, the composition may be cured at a stage prior to a casting or coating process for applying the composition to a desired use. A method for curing an ultraviolet curable resin composition, which comprises irradiating an object with ultraviolet energy evenly to induce a polymerization reaction in advance. 2. The treatment method according to claim 1, wherein the ultraviolet curable resin composition is a mixture of an epoxy resin and a cationic polymerization catalyst.