JP2002294215A - Sealing method using one-pack photo-curable resin or one-pack photo-and heat-curable resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing method using a one-pack photo-curable resin or a one-pack photo-and heat-curable resin, which does not need large facilities and moreover can seal sufficiently a sealing part, where light hardly reaches, owing to curing by a short-time photo-irradiation. SOLUTION: The sealing method comprises developing a photo-curable resin, of which the curing reaction is activated by photo-irradiation and which is liquid at normal temperatures, into a thin layer, irradiating light to the thin layer, and injecting the thin layer into a sealing part while the photo-curable resin is liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing method using a one-part photo-curable resin or a one-part photo-thermosetting resin.

[0002]

2. Description of the Related Art There is known a method of sealing a connection portion between a circuit board and a conductive wire with a resin in order to protect the connection portion from corrosion or impact by water. The curing method of the sealing material includes a thermosetting type and a photosetting type. As a thermosetting type, a two-part mixed epoxy resin is known. For example, a composition containing an epoxy resin and a silicone-modified epoxy resin and an acid anhydride or an amine as a curing agent is disclosed in JP-A-6-24000. Has been proposed. As the photo-curing type, a photo-radical curing type and a photo-cation curing type are known. Examples of the photo-cation curing type include, for example, JP-A-6-109333.
Japanese Patent Laid-Open Publication No. HEI 9-264, proposes a composition comprising a bisphenol-type epoxy, a compound containing a hydroxyethyl group, an alkoxysilane, and a cationic photopolymerizing agent.

[0003] However, the encapsulant made of the above-mentioned two-part mixed epoxy resin needs to be mixed with two parts (main agent and curing agent) before filling in the sealing part, so that the work is complicated and two-part There were problems such as the pot life of the mixture being restricted. In addition, in the photo-curing type sealing material, in order to increase the pot life after light irradiation, when the amount of the hydroxyl group-containing compound is increased, it takes time to completely cure, or does not cure sufficiently. There was something. When the curing time is shortened, the pot life after light irradiation is shortened, and handling may be difficult.

However, in order to cure the photocurable resin, a sufficient amount of light irradiation is necessary. When the coating film of the photocurable resin is thick, light hardly reaches the central portion, and the light reaches the center. There is a disadvantage that the hardening of the part which has not been performed is insufficient. As a countermeasure for this, methods such as increasing the intensity of light to be irradiated and increasing the light irradiation time have been used.
However, this method requires extensive equipment,
There are problems such as a decrease in manufacturing efficiency due to a long working time.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to eliminate the need for large-scale equipment and to cure by short-time light irradiation. It is an object of the present invention to provide a sealing method using a one-pack type photo-curable resin or a one-pack type photo-thermosetting resin which can sufficiently seal even a portion of the sealing portion where light is difficult to reach.

[0006]

According to a first aspect of the present invention, there is provided a sealing method using a one-part photocurable resin, in which a curing reaction is activated by light irradiation. It is characterized in that a photocurable resin liquid at room temperature is developed into a thin layer, the developed photocurable resin is irradiated with light, and then injected into the sealing portion while the photocurable resin is in a liquid state. .

In the sealing method using the one-pack type photo-thermosetting resin of the invention described in claim 2 (hereinafter referred to as the second invention), the curing reaction substantially proceeds by heating before light irradiation. After the curing reaction is activated by light irradiation, the light- and thermosetting resin is cured by heating. It is characterized in that it is injected into the sealing part during a certain period and then heated.

The sealing method using the one-pack type photo-thermosetting resin according to the third aspect of the invention (hereinafter referred to as the third invention) seals the liquid photo-thermosetting resin at room temperature. After the injection into the part, the surface of the photo-thermosetting resin is irradiated with light, a cured film is formed on the surface so that the injected resin does not flow out, and then heated.

Hereinafter, the present invention will be described in detail. In the sealing method of the first invention, a one-part photocurable resin that is liquid at room temperature is used as the sealing material. Room temperature (2
The use of a liquid at 3 ° C. facilitates the reaction and facilitates development and handling into a thin layer. The term "liquid at normal temperature" as used herein means that the viscosity before light irradiation is preferably 0.1.
001 to 100 Pa · s, more preferably 0.0
01 to 10 Pa · s, more preferably 0.001 to 5
Pa · s. When the viscosity at room temperature exceeds 100 Pa · s, it becomes difficult to fill the details of the complicated circuit board with the photocurable resin.

As the photocurable resin, a compound or polymer having a vinyl ether group, an episulfide group, an ethyleneimine group or an epoxy group in the molecule is used, and a compound having an epoxy group is particularly preferable. An epoxy resin is preferably used as the compound having an epoxy group, and bisphenol A is used as the epoxy resin.
And epoxy resins such as bisphenol F type, phenol novolak type, cresol novolak type, glycidyl ether type and alicyclic type.

As the epoxy resin, an oligomer containing an epoxy group can also be used. Examples of commercially available bisphenol A type epoxy oligomers include "Epicoat 1001", "Epicoat 1002", "Epicoat 1004", "Epicoat 1007", and "Epicoat 1010" manufactured by Yuka Shell Epoxy.

As the epoxy resin, an addition polymer of an epoxy group-containing monomer or oligomer can be used. Examples of such an addition polymer include glycidylated polyester, glycidylated polyurethane, and glycidylated acrylic polymer. And the like. The glycidylated acrylic polymer is obtained by reacting an acrylic polymer having a hydroxyl group with epichlorohydrin; a method of copolymerizing a glycidyl (meth) acrylate with an acrylic polymer having a hydroxyl group; It can be obtained by a method of reacting a bifunctional or higher epoxy resin or the like.

In order to impart flexibility to the above epoxy resin, a monofunctional epoxy resin having one epoxy group in one molecule may be used in combination. Commercially available monofunctional epoxy resins include, for example, "Heroxy 7, 8, 9, 62, 65, 116" manufactured by Japan Epoxy Resin; "Epolite M-1230" manufactured by Kyoeisha Yushi Kagaku; Nippon Kayaku Co., Ltd. B
GE, PGE, BR-250, BROC "and the like.

When the above monofunctional epoxy resin is used in combination, the weight ratio of the compound having two or more functional epoxy groups / the compound having the monofunctional epoxy group is 95/5 to 60/40.
And more preferably 90/10 to 7
0/30. If the amount of the compound having a monofunctional epoxy group is less than the above range, sufficient flexibility may not be obtained, and cracking may occur during curing.If the amount is more than the above range, the reactivity decreases, and heating for a short time is performed. May not cure.

A compound having a hydroxyl group may be used in combination with the epoxy resin, if necessary. Examples of the compound having a hydroxyl group include polyether-based polyol, polyester-based polyol, polycarbonate-based polyol, polymer polyol, and rosinol. These may be used alone or in combination of two or more.

The above polyether polyols include:
Although not particularly limited, for example, active hydrogen
A polymer obtained by subjecting an alkylene oxide to ring-opening polymerization in the presence of at least one low molecular weight active hydrogen compound is suitably used.

Specific examples of the low-molecular-weight active hydrogen compound having two or more active hydrogens include diols such as bisphenol A, ethylene glycol, propylene glycol, butylene glycol, and 1,6-hexanediol; Triols such as methylolpropane; and amines such as ethylenediamine and butylenediamine. These may be used alone or in combination of two or more.

Specific examples of the above-mentioned alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, amylene oxide, hexylene oxide, and tetrahydrofuran. These may be used alone or in combination of two or more.

Specific examples of the polyester-based polyol include polybasic acids such as adipic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid and succinic acid, and bisphenol A, ethylene glycol, 1,2
A polymer obtained by dehydrating and condensing polyhydric alcohols such as propylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol and neopentyl glycol; ε-caprolactone, α-methyl-
lactone polymers such as ε-caprolactone; condensates of a hydroxycarboxylic acid such as castor oil, a reaction product of castor oil with ethylene glycol, and the above polyhydric alcohol; These may be used alone or in combination of two or more.

Commercially available polycarbonate polyols include, for example, "PNOC-100" manufactured by Kuraray Co., Ltd.
0 "," PNOC-2000 "," Kuraray polyol C "
-1090 "and" Kuraray polyol C-2090 ".

Specific examples of the polymer polyol include, for example, acrylonitrile, styrene,
A graft polymer obtained by graft polymerization of an ethylenically unsaturated compound such as methyl (meth) acrylate;
Examples thereof include 2-polybutadiene polyol, 1,4-polybutadiene polyol, and hydrogenated products thereof. The weight average molecular weight of this polymer polyol is 1,
About 2,000 to 2,000 is preferable. Examples of such commercially available products include “UH-2000” manufactured by Toa Gosei Co., Ltd.
“UH-2030”, “UH-2080”, “UH-2”
011 ”and the like.

Specific examples of the rosinol include, for example, an ester of a compound having a carboxyl group of rosin and two or more hydroxyl groups; a compound obtained by reacting a compound having a carboxyl group of rosin with an epoxy group; a rosin skeleton And a compound having both a hydroxyl group and a hydroxyl group.

The above-mentioned rosin is an abietic acid type resin acid such as abietic acid, neoabietic acid, dehydroabietic acid, levopimaric acid, parastolic acid; a pimaric acid type resin acid such as pimaric acid, isopimaric acid, sandaracopimaric acid;
Alternatively, a resin acid obtained by hydrogenating or disproportionating them may be used. These may be used alone or in combination of two or more. As commercial products of rosin, for example,
Arakawa Chemical's "KE-359", "SR-200",
“SR-30PX”, “KE-601”, “KE-61”
5-3 "and" KE-624 modified ".

Among the compounds having a hydroxyl group, polyester polyols, polycarbonate polyols, polymer polyols, rosinols and the like are particularly preferable.
These may be used in combination with a polyether-based polyol. By using the compound having a hydroxyl group,
Curing at the time of light irradiation can be suppressed.

The number of moles of the epoxy group of the compound having an epoxy group: the number of moles of the hydroxyl group of the compound having a hydroxyl group = 1: 1
0.001-1: 0.03 is preferred. When the number of moles of the hydroxyl group is less than 0.001, curing proceeds during or shortly after light irradiation, so that the sealing portion may not be filled. Cannot be sufficiently cured by heating.

The epoxy resin may be used in combination with a flexible epoxy resin. Since a flexible cured product is obtained by using a flexible epoxy resin in combination, impact resistance and adhesive strength are improved. The compounding amount of the flexible epoxy resin is 10
10 to 100 parts by weight per 0 parts by weight is preferred. If the amount is less than 10 parts by weight, sufficient peel adhesion strength cannot be obtained. Commercially available flexible epoxy resins include, for example, “BPO-20E” and “BEO-40” manufactured by Nippon Rika Co., Ltd.
E "," BEO-60E "," KRM240 "manufactured by Asahi Denka Co., Ltd.
0 "and the like.

As a curing catalyst for the photocurable resin, a photocationic catalyst that generates cations by light irradiation is used. As the photocationic catalyst, for example, “OPTMA-SP-150” and “OPTOMA-SP-17” manufactured by Asahi Denka Co., Ltd.
0 "and" UV16990 "manufactured by Union Carbide Co., Ltd.

The amount of the photocationic catalyst is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the photocurable resin. When the amount is less than 0.5 part by weight, the composition is not sufficiently cured by light irradiation, and when the amount exceeds 5 parts by weight, the pot life becomes short and the composition may be cured during the light irradiation.

A filler, a silane coupling agent, a plasticizer, and the like may be added to the photocurable resin. As the filler, those having a refractive index of 1.45 to 1.65 are preferable,
More preferably, it is 1.5 to 1.6. Refractive index is 1.4
When it is less than 5 or more than 1.65, light scattering becomes large, and it is difficult for light to reach the central portion of the applied photocurable resin, which may not be sufficiently cured.

As the filler, for example, alumina,
Examples include talc, silica sand, quartz sand, mica, magnesium hydroxide, bentonite, kaolin, barium sulfate, glass balloon, Aerosil, and aluminum oxide. These may be used alone or in combination of two or more. The shape of the filler, powder, scale,
It may be spherical, massive, needle-shaped, or the like.

The amount of the filler is preferably 10 to 200 parts by weight, more preferably 50 to 100 parts by weight, based on 100 parts by weight of the total amount of the epoxy resin and the curing catalyst. The filler is not limited as long as it can sufficiently transmit ultraviolet light when added to the epoxy resin. For example, when 50 parts by weight of the additive is added to 100 parts by weight of the epoxy resin, 365n with a thickness of 1mm
Those which transmit 30% or more of ultraviolet rays of m are preferable.

Examples of the silane coupling agent include aminoalkoxysilanes such as γ-aminomethyltriethoxysilane and N-β (aminoethyl) -γ-aminopropyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane and the like. A mercaptoalkoxysilane;
γ-glycidoxypropyltrimethoxysilane, 3,4
An epoxyalkoxysilane such as epoxycyclohexylethyltrimethoxysilane; a vinylsilane such as vinyltris (β-methoxyethoxy) silane and vinyltriethoxysilane; one isocyanate group and one alkoxysilyl group such as γ-isocyanatopropyltriethoxysilane. And the like. These may be used alone or in combination of two or more.

Particularly, as the silane coupling agent, a compound having both an alicyclic epoxy group and an alkoxysilyl group is preferable, and as a commercially available product of such a compound, for example, “KRM303” manufactured by Shin-Etsu Chemical Co., Ltd. And the like. Such a compound exhibits high adhesive strength, for example, by sufficiently reacting the epoxy group of the silane coupling agent and the epoxy group of the epoxy resin on the adhesive surface.

The amount of the silane coupling agent is preferably 0.05 to 3 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the total amount of the epoxy resin and the curing catalyst. . If the compounding amount is less than 0.05 part by weight, sufficient peel adhesion and impact resistance cannot be obtained, and if it exceeds 3 parts by weight, bleed out to the bonding interface and the peeling adhesive strength is reduced.

Examples of the plasticizer include dioctyl phthalate (DOP), dibutyl phthalate, dilauryl phthalate, dioctyl adipate, diisodecyl adipate, tributyl phosphate, trioctyl phosphate, propylene glycol adipate polyester, butylene glycol adipate polyester, epoxy Petroleum soybean oil, chlorinated paraffin, liquid paraffin and the like. These may be used alone or in combination of two or more.

In the sealing method of the first invention, a mixture of a photocurable resin and a curing catalyst is used as a sealing material, and the sealing material is developed into a thin layer and then irradiated with light. The photocurable resin is activated by light irradiation to start a curing reaction, but it is preferable to inject the resin into a sealing portion (a portion to be sealed) while the curing reaction does not progress much and the liquid is maintained. After the photocurable resin is injected into the sealing portion, the curing reaction proceeds and is cured, thereby sealing the sealing portion.

As a method of developing the sealing material into a thin layer, for example, a smooth surface (glass plate,
A metal plate) by a knife coater, a slip coater, a roll coater, a spray, or the like.

The portion to be irradiated with light is preferably the entire thin layer on which the sealing material is uniformly applied. For example, light is irradiated using a light irradiation device. Further, in order to uniformly irradiate light over a wide range, it is preferable to apply a sealing material on a reflecting mirror and use a fluorescent lamp type (rod shape) as a light source. Heat at the time of light irradiation may be used to accelerate the curing reaction, or the reaction may be controlled by cutting off light using a filter. When skinning on the surface of the thin layer becomes a problem, the skinning on the surface of the thin layer can be suppressed by cutting ultraviolet light having a short wavelength with a filter or the like.

The amount of light irradiation is preferably sufficient to photoactivate the photocurable resin, and can maintain a liquid state until it is injected into the sealing portion. The range is preferably from 5 to 5 J / cm ² .

Examples of the light source used for light irradiation include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

Next, the second invention will be described. In the sealing method of the second invention, a one-part photo-thermosetting resin liquid at room temperature is used as the sealing material. As the photo-thermosetting resin, a resin which does not substantially undergo a curing reaction by heating before light irradiation and is cured by heating after the curing reaction is activated by light irradiation is used. As such a photo-thermosetting resin, the same photo-setting resin as in the first invention can be used.

As the curing catalyst for the photo-thermosetting resin, a photo-cation catalyst and a thermo-cation catalyst are used in combination, and the same photo-cation catalyst as in the first invention is used. The thermal cation catalyst generates cations by heating. For example, “C” manufactured by Asahi Denka Co., Ltd.
P-66 "," CP-77 ", Nippon Soda Co., Ltd." CIT-
Commercially available products such as "1370" and "CIT-1672".

The compounding ratio (weight ratio) of the above-mentioned photocationic catalyst and thermal cation catalyst is preferably photocationic catalyst / thermal cation catalyst = 90/10 to 10/90. When the amount of the photocationic catalyst is larger than the above range, it may be cured at the time of light irradiation, or there is a possibility that a portion where light is not sufficiently irradiated by heat curing may not be cured. Therefore, when used as a one-pack type, there is a possibility that storage stability may be deteriorated.

The compounding amount (total amount) of the photocationic catalyst and the thermocationic catalyst is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the photo-thermosetting resin. The amount is 0.5
If the amount is less than 5 parts by weight, the epoxy resin may not be sufficiently cured.
The epoxy resin may deteriorate.

In the second invention, a compound which generates a cation by either light or heat may be used as a curing catalyst. Examples of such a light / thermal cation catalyst include “SI-60L” and “SI-80” manufactured by Sanshin Chemical Co., Ltd.
L "," SI-100L ", Nippon Soda Co., Ltd." CIP-1
866S "," CPI-2058S "," CPI-20
64S "," CI-1370 "," CI-2397 ",
"CI-2481", "CI-2624", "CI-2
064 "and the like.

The compounding amount of the above-mentioned photo-thermal cation catalyst is
The amount is preferably 0.5 to 3 parts by weight, more preferably 1 to 2 parts by weight, per 100 parts by weight of the thermosetting resin. If the amount is less than 0.5 parts by weight, the epoxy resin may not be sufficiently cured even after heating. If the amount exceeds 3 parts by weight, a sufficient pot life may not be obtained or the epoxy resin may be cured during light irradiation. is there.

In the sealing method of the second invention, a mixture of a photo-thermosetting resin and a curing catalyst is used as a sealing material, and the sealing material is irradiated with light after being developed into a thin layer. The photo-thermosetting resin is activated by light irradiation and starts a curing reaction, but it is preferable to inject the resin into the sealing portion while the curing reaction does not proceed so much and the liquid is kept. After the light / thermosetting resin is injected into the sealing portion, the resin is heated and cured, and the sealing portion is sealed.

As a method for developing the sealing material into a thin layer and a method for irradiating light, the same method as in the first invention is used. As a heating method, a conventionally known method such as heating in an oven can be used.

In the second invention, the reaction rate of the epoxy group of the epoxy resin when the sealing material is irradiated with light is preferably 15% or less, and the epoxy resin when heated at 60 to 150 ° C. for 1 to 15 minutes. The reaction rate of the group is preferably 50% or more. If the heating temperature is lower than 60 ° C., the epoxy resin cannot be sufficiently cured, and if the heating temperature exceeds 150 ° C., the heat-sensitive adherend may be deteriorated.

Next, the third invention will be described. In the sealing method of the third invention, a one-part photo-thermosetting resin that is liquid at normal temperature and similar to that of the second invention is used as the sealing material. After the sealing material is injected into the sealing portion, light irradiation is performed to form a cured film on the surface so that the injected sealing material does not flow out. Next, the light / thermosetting resin is cured by heating, and the sealing portion is sealed.

As the light irradiation method and the heating method,
A method similar to the invention is used.

In the second and third inventions, the same filler, silane coupling agent, plasticizer and the like as in the first invention may be added to the photo-thermosetting resin.

[0053]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention and comparative examples will be described. (Example 1) Epoxy resin ("Epicoat 828" manufactured by Japan Epoxy Resin Co., Ltd.), monofunctional epoxy resin ("Heroxy 62" manufactured by Japan Epoxy Resin Co., Ltd.) and photocationic catalyst (Union Carbide Co., Ltd.) in the amounts shown in Table 1 "UV16990") was stirred and mixed at room temperature until the mixture became uniform to obtain a sealing material.

After reducing the pressure of the sealing material to remove air bubbles and developing the sealing material on a smooth metal plate, light having a wavelength of 365 nm was emitted using an ultra-high pressure mercury lamp (“J-2300” manufactured by Oak Manufacturing Co., Ltd.). Ultraviolet irradiation was performed for 15 seconds so as to obtain 40 mW / cm ² . Then, after leaving the sealing material on the metal plate in an aluminum cup having a diameter of 5 cm × a depth of 1 cm and left for 1 day, the curability was evaluated by visual observation according to the following criteria. ：: Cured evenly, there was no gap between the aluminum cup and the cured product, and no crack was generated in the cured product. ×: Cured during light irradiation or insufficiently cured.
A gap between the aluminum cup and the cured product, or a crack in the cured product

(Examples 2, 3 and Comparative Examples) Epoxy resins (“Epicoat 828” manufactured by Japan Epoxy Resin) and monofunctional epoxy resins (“Heroxy 62” manufactured by Japan Epoxy Resin) in the amounts shown in Table 1 , A photocationic catalyst (“UV16990” manufactured by Union Carbide), a thermal cation catalyst (“CP-77” manufactured by Asahi Denka Co., Ltd.)
A cationic catalyst (“S160L” manufactured by Sanshin Chemical Co., Ltd.) was stirred and mixed at room temperature until uniform, to obtain a sealing material.

After removing the air bubbles by reducing the pressure of the sealing material,
After filling into a 5cm diameter x 1cm deep aluminum cup,
Ultraviolet light was applied for 45 seconds using an ultra-high pressure mercury lamp (“J-2300” manufactured by Oak Manufacturing Co., Ltd.) so that light having a wavelength of 365 nm became 40 mW / cm ² . Then, put the aluminum cup in a 130 ° C. oven for 5 minutes to cure it,
The curability was evaluated in the same manner as in Example 1.

[0057]

[Table 1]

In the comparative example, the sealing material is cured during light irradiation,
After the oven was heated, the sealing material at the bottom of the aluminum cup was not sufficiently cured.

[0059]

The sealing method using the one-pack type photo-curable resin or the one-pack type photo-thermo-curable resin according to the present invention has the above-mentioned structure, does not require large-scale equipment, and can be performed in a short time. By activating and curing by the light irradiation of the above, it is possible to sufficiently seal even a portion of the sealing portion where light hardly reaches.

Claims (3)

[Claims] 1. A photocurable resin that is liquid at room temperature, in which a curing reaction is activated by light irradiation, is developed into a thin layer and irradiated with light, and then injected into a sealing portion while the photocurable resin is liquid. A sealing method using a one-part type photocurable resin. 2. A thin layer of a photo-thermosetting resin which is liquid at room temperature and hardens by heating after the curing reaction does not substantially proceed by heating before the light irradiation and is hardened by the heating after the curing reaction is activated by the light irradiation. And then irradiating with light, injecting into the sealing portion while the photo-thermosetting resin is in liquid state, and then heating, using one-pack type photo-thermosetting resin Method. 3. Injecting a liquid photo-thermosetting resin at room temperature into a sealing portion, and then irradiating the surface of the photo-thermosetting resin with light,
A sealing method using a one-component photo-thermosetting resin, wherein a cured film is formed on the surface so that the injected resin does not flow out, and then heated.