JP2018045053A - Portable information terminal and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a portable information terminal capable of easily bonding a housing and a cover panel, and a manufacturing method thereof.SOLUTION: A portable information terminal 100 includes: a housing 10 for housing a display panel 6; a cover panel 20 for protecting the display panel 6; and a bonding part 5 for bonding the housing 10 and the cover panel 20. The bonding part 5 is a cured adhesive material 3 which is in a liquid state immediately after irradiation with active energy ray and cures after predetermined time has passed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a portable information terminal and a manufacturing method thereof. Specifically, the present invention relates to a portable information terminal such as a smartphone, a mobile phone, a car navigation system, a digital camera, a notebook computer, a tablet computer, a head mounted display, a wristwatch type terminal, an electronic notebook, an electronic dictionary, and a manufacturing method thereof.

  As a portable information terminal, a mobile information terminal has been proposed that includes a housing that accommodates a display panel and a cover panel that protects the display panel. And a housing | casing and a cover panel are adhere | attached using a double-sided tape (for example, refer patent document 1).

JP 2010-157957 A

  However, due to the downsizing of the housing and the narrow frame of the cover panel, the area where the housing and the cover panel are bonded is reduced, making it difficult to place the double-sided tape on the adhesive surface. There was a problem that became difficult.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a portable information terminal and a method for manufacturing the portable information terminal that can easily bond a housing and a cover panel.

The portable information terminal according to the present invention is
A housing for housing the display panel;
A cover panel for protecting the display panel;
A portable information terminal comprising an adhesive part for adhering the housing and the cover panel,
The adhesive portion is liquid immediately after irradiation with ultraviolet rays, and is a cured product of an adhesive that cures after a predetermined time has elapsed.

A method for manufacturing a portable information terminal according to the present invention includes:
A housing for housing the display panel;
A cover panel for protecting the display panel;
A method of manufacturing a portable information terminal comprising an adhesive portion that bonds the housing and the cover panel,
The adhesive part is liquid immediately after irradiation with ultraviolet rays, and is a cured product of an adhesive that cures after a predetermined time has elapsed,
The adhesive is supplied linearly to at least one of the adhesive surface of the housing and the adhesive surface of the cover panel,
In the cross section in the direction orthogonal to the longitudinal direction of the adhesive, the dimension of the direction protruding from the adhesive surface of the adhesive is ½ or more of the dimension in the direction orthogonal to the protruding direction. .

  In the present invention, even if the area where the casing and the cover panel are bonded is small, the liquid adhesive is easy to supply, and the casing and the cover panel can be easily bonded.

FIG. 1 shows a portable information terminal according to an embodiment of the present invention, and is a YY cross-sectional view in FIG. FIG. 2 is a front view of the same. FIG. 3 is an enlarged cross-sectional view of a portion X in FIG. FIG. 4 is an enlarged cross-sectional view showing another embodiment of the above. FIG. 5 is an enlarged cross-sectional view showing another embodiment of the above. FIG. 6A is a plan view showing an example of the casing. FIG. 6A is an enlarged sectional view showing a part of the casing. FIG. 6C is an enlarged cross-sectional view showing a state where a part of the adhesive of the casing is supplied. FIG. 7 is a cross-sectional view showing an example of the irradiation process. FIG. 8 is a cross-sectional view showing an example of the bonding step. FIG. 9A is a cross-sectional view showing an example of the adhesive placement step. FIG. 9B is a cross-sectional view showing a state in which the same adhesive is disposed. FIG. 10A is a plan view showing an example of a housing in the third embodiment. FIG. 10A is an enlarged cross-sectional view showing a part of the housing in the third embodiment. FIG. 10C is an enlarged cross-sectional view showing a state where a part of the adhesive in the housing in Example 3 is supplied. FIG. 11 is an atomic force microscope photograph obtained by photographing the bonding surface of the housing in Example 1 described above. FIG. 12 is an atomic force micrograph of the bonding surface of the housing in Example 2 described above.

  Hereinafter, modes for carrying out the present invention will be described.

(Description of portable information terminal)
1 and 2 show a portable information terminal 100 according to the present embodiment. The portable information terminal 100 is a portable electronic device such as a smartphone. Examples of other electronic devices include those shown in the technical field, such as portable game machines and mobile phones. In such a portable information terminal 100, a reduction in size and weight and a reduction in price are always demanded. In order to reduce the overall weight as much as possible, the number of adhesive members is reduced, and a reduction in adhesion area due to downsizing leads to a thin wire. Adhesion at is required. Furthermore, it is very important to reduce production costs for price reduction. An adhesive comprising a photocationic polymerization composition described below satisfies these needs.

  The portable information terminal 100 includes a display panel 6, a housing (frame) 10, a cover panel 20, an adhesive portion 5, and the like. The housing 10 and the cover panel 20 are assembled by being bonded by the bonding portion 5. In addition to these, the portable information terminal 100 may include, for example, a battery 71, a circuit board 72, and the like.

  The display panel (display unit) 6 is a liquid crystal panel or the like, and is a device that displays characters and images. The display panel 6 is not limited to a liquid crystal panel, and may be an organic EL display panel. In this case, a backlight is not required and the light is not lit at all times, so that power is saved, and since the light emission is organic EL self-light emission, the total light emission amount is reduced, and the dye contained in the adhesive portion 5 necessary for light shielding It is possible to reduce the amount of pigments and pigments, and there is an advantage that the degree of freedom such as the amount of ultraviolet rays for curing and the coating shape is increased.

  The housing 10 is made of plastic or metal, and has a rectangular plate-like bottom portion 11 and a side wall portion 12 rising from the peripheral end portion of the bottom portion 11 toward the front side. A space surrounded by the bottom part 11 and the side wall part 12 is formed as a housing part 8. The housing 10 is open on the opposite side of the bottom 11.

  The cover panel 20 has a panel body 22 and a decorative printing unit 21. The panel body 22 is made of resin (plastic) or glass and is formed in a rectangular plate shape. The panel main body 22 has transparency that does not cause a practical problem of the portable information terminal 100. The panel body 22 is exemplified by a glass plate, but is not limited thereto, and may be a resin plate made of polycarbonate, acrylic, PMMA, polyolefin, or the like having high translucency, or a laminate or composite of these resin plates. If a resin plate is used, it can be configured as a curved display or a display that does not break. When the panel body 22 is not a glass plate, it is common to provide an ultraviolet absorbing material from the viewpoint of weather resistance in addition to performing a hard coat so that the panel body 22 is not easily scratched. In this case as well, even in this case, it is possible to perform pasting with a delayed-curing adhesive described later. In addition, since the adhesive remains in a liquid state in an uncured state, it can be bonded even on a curved surface, and if it has shape retention in consideration of viscosity and thixotropy, the thickness and width of the adhesive can be stably maintained. It can be controlled and is preferable.

  The panel main body 22 has a decorative printing portion 21 over the entire length of the peripheral end portion on the back surface thereof. The decorative printing unit 21 has a light shielding property so that a portion on the inner side (housing 10 side) than the decorative printing unit 21 cannot be seen through the peripheral end of the panel main body 22. Therefore, the decorative printing part 21 makes it difficult to see the adhesive part 5 and the like, and the product design is improved. The decorative printing unit 21 is, for example, a printing film (ink film) formed by screen-printing acrylic or urethane ink. In addition, the cover panel 20 has been increasingly coated with a high UV-absorbing property to enhance weather resistance, and light can hardly be transmitted to the back side (housing 10 side) of the decorative printing unit 21. There is also.

  Components 7 such as a battery 71 and a circuit board 72 are accommodated in the accommodating portion 8. Further, the display panel 6 is provided on the back surface of the cover panel 20 (the surface on the housing portion 8 side) by bonding or the like. The display panel 6 is also accommodated in the accommodating portion 8 on the front side of the component 7.

  The bonding portion 5 is interposed between the housing 10 and the cover panel 20 to bond the housing 10 and the cover panel 20 together. As shown in FIG. 3, the bonding portion 5 is bonded to the housing 10 at the position of the concave portion 13 formed at the front side end portion (opening edge portion of the housing portion 8) of the side wall portion 12. The concave portion 13 is formed over the entire circumference of the side wall portion 12 so as to surround the opening of the accommodating portion 8. The bonding portion 5 is provided over the entire length of the concave portion 13 in the circumferential direction. The bonding part 5 is bonded to the cover panel 20 at the position of the decorative printing part 21. That is, the adhesive surface 10a of the housing 10 that is the bottom surface of the recess 13 and the adhesive surface 20a that is the back surface of the decorative printing portion 21 of the cover panel 20 are arranged to face each other, and between the adhesive surface 10a and the adhesive surface 20a. An adhesive portion 5 is provided.

  Here, the dimension (thickness) T of the bonding portion 5 in the facing direction between the bonding surface 20a of the cover panel 20 and the bonding surface 10a of the housing 10 is preferably 30 to 200 μm, and more preferably 50 to 150 μm. preferable. Thereby, when the portable information terminal 100 is dropped, an impact applied to the adhesion interface between the housing and the cover panel is easily absorbed by the adhesion part 5, and the interface between the display panel 6 and the adhesion surface 10 a and the adhesion part 5 is easily absorbed. Can reduce damage.

  As shown in FIG. 4, it is preferable that one or both of the adhesive surface 20a of the cover panel 20 and the adhesive surface 10a of the housing 10 is an uneven surface. Thereby, compared with the case where the bonding surfaces 10a and 20a are flat, the bonding area between the bonding surfaces 10a and 20a and the bonding portion 5 is increased, and the bonding strength between the cover panel 20 and the housing 10 can be increased. The roughness of the uneven surface may be nano level. Further, the uneven surface can be formed by providing a large number of protrusions with respect to the plane. In this case, the convex can be formed in a hemispherical shape having a height of 50 nm and a diameter of 50 nm. In addition, when the adhesion surfaces 10a and 20a are uneven surfaces, it is preferable to make the dimension T of the adhesion part 5 larger than the height difference of the unevenness of the uneven surfaces. In order to make the bonding surfaces 10a and 20a uneven, a plasma cleaning process is performed after the housing 10 and the decorative print layer 21 are formed.

  Moreover, once the cover panel 20 and the housing 10 are peeled off, it becomes difficult to properly adhere again due to the uneven surface, which is effective as a countermeasure against counterfeit products. As shown in FIGS. 5, 6 </ b> A, and 6 </ b> B, a protrusion 15 is preferably formed on the bonding surface 10 a of the housing 10. One or a plurality of protrusions 15 can be provided. The plurality of protrusions 15 can be randomly provided on the housing 10, for example, can be provided at asymmetric positions with respect to the opening of the housing 10. As shown in FIG. 6C, the protrusion 15 is covered with the adhesive 3 when the adhesive 3 is supplied to the adhesive surfaces 10a and 20a.

  By providing such a protrusion 15 on the bonding surface 10a of the housing 10, it becomes easy to prevent the appearance of a counterfeit product that is a copy of the structure of the housing 10. Specifically, when a regular product having protrusions 15 is obtained, a mold is made from the housing 10 and a copy is made, the protrusions 15 abut on the double-sided tape or the like and cannot be disposed on the adhesive surface 10a. Further, when the protrusions 15 are added asymmetrically to the left and right, it is difficult to attach the cover panel 20 and the display panel 6 horizontally. For this reason, the protrusion 15 is exposed and the casing 10 and the cover panel 20 cannot be bonded together unless an adhesive having a high shape-retaining property having the same viscosity and thixotropy used for a regular product is obtained. In this way, it is possible to discriminate between genuine products, unauthorized modification, and counterfeit products.

  Moreover, it is preferable that the adhesion part 5 contains the coloring material. As the coloring material, one or both of a dye and a pigment can be used. For example, the adhesion part 5 can be made black by making the adhesion part 5 contain coloring materials, such as carbon black. By adding black to the bonding part 5 and bonding the housing 10 and the cover panel 20, it becomes difficult to visually recognize even if the bonding part 5 protrudes from the gap between the housing 10 and the cover panel 20, Design can be improved. Moreover, it is possible to reduce or prevent light from leaking through the bonding portion 5 when the user operates the portable information terminal 100 in a dark place by coloring to a transmittance that does not transmit light in the visible light range. .

  Moreover, the adhesion part 5 may contain the light absorption material which absorbs a specific wavelength. This can be adjusted so as to intensively absorb the wavelength corresponding to the emission wavelength of the white LED of the backlight used in a liquid crystal panel or the like. Specifically, a white LED is used as the backlight. In this case, the backlight is visually recognized as white by combining light emitted from light sources of 450 nm, 540 nm, and 640 nm. Therefore, light can be efficiently absorbed by using light absorbing materials corresponding to 450 nm, 540 nm, and 640 nm, respectively. Further, since the light absorbing material absorbs only a specific wavelength and does not absorb much light in other wavelength bands, it does not absorb the wavelength of 365 nm, which is an active energy ray, and shields visible light, but also UV adhesive 3. Can be efficiently cured. As these materials, a material that absorbs a desired wavelength among copper porphyrin complex, cobalt porphyrin complex, iron oxide, copper oxide, metal phthalocyanine, azo dye, and the like may be used in appropriate combination.

  In the above, a light absorbing material that absorbs a specific wavelength in accordance with the light emission wavelength of the backlight is included. However, the present invention is not limited to this, and the housing 10 has a light emission light source and is emitted from the light emission light source. By containing a light-absorbing material corresponding to the wavelength of light, light emitted from the light source inside the housing 10 via the adhesive portion 5 can be made difficult to leak to the outside. For example, in a portable information terminal using a head mounted display, a wavelength of 635 nm may be used as a light source of a display unit. At this time, if an appropriate amount of Fe-phthalocyanine or the like is contained in the bonding unit 5 as a light absorbing material. Good.

  The content of the dye, the pigment and the light absorbing material is preferably 0.005 to 1 wt% with respect to the total weight of the bonding portion 5, but the type of the colorant and the light absorbing material, the type of the adhesive, and the necessity It can be set as appropriate according to the light shielding performance to be performed.

(Description of adhesive)
The portable information terminal 100 adheres the housing 10 and the cover panel 20 with the adhesive 3.

  As the adhesive 3, an adhesive that is liquid immediately after irradiation with an active energy ray such as ultraviolet rays and hardens after elapse of a predetermined time is used. As such an adhesive 3, a photocationic polymerization composition is used.

  Adhesive 3 which is a cationic photopolymerization composition is composed of (A) a polyfunctional epoxy compound having two or more epoxy groups in one molecule (hereinafter also referred to as component (A)), and (B) one molecule. It contains a monofunctional epoxy compound having one epoxy group (hereinafter sometimes referred to as (B) component) and (C) a photocation generator (hereinafter sometimes referred to as (C) component). ing. In addition to the component (A), the component (B), and the component (C), the component (D) may contain an oxetane compound (hereinafter sometimes referred to as the component (D)). Further, in addition to the component (A), the component (B), the component (C), and the component (D), (E) an elastomer (hereinafter sometimes referred to as the component (E)) may be included. Such a cationic photopolymerization composition has delayed curing properties and can be used as a delayed curing adhesive. In addition, arbitrary components, such as various resin and an additive, may be mix | blended as needed in the photocationic polymerization composition of this embodiment in the range which does not impair delayed curability.

  The polyfunctional epoxy compound having two or more epoxy groups in one molecule as the component (A) is a compound having two or more functional epoxy groups in one molecule.

  The component (A) includes at least one of a polyfunctional epoxy compound (A1) having a polyether skeleton in one molecule and a polyfunctional epoxy compound (A2) having no polyether skeleton in one molecule.

  The polyfunctional epoxy compound (A1) is polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, or the like. A polyfunctional epoxy compound (A1) can be used individually by 1 type from the above, or can use 2 or more types together.

  The polyfunctional epoxy compound (A2) is bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, biphenyl type epoxy having a biphenyl skeleton. Resin, naphthalene ring-containing epoxy resin, anthracene ring-containing epoxy resin, alicyclic epoxy resin, dicyclopentadiene type epoxy resin having dicyclopentadiene skeleton, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane type epoxy Resins, bromine-containing epoxy resins, aliphatic epoxy resins, aliphatic polyether epoxy resins, triglycidyl isocyanurate, and the like. A polyfunctional epoxy compound (A2) can be used individually by 1 type from the above, or can use 2 or more types together.

  In the present specification, the “polyether skeleton” means the following chemical structural formula (1).

(In the chemical structural formula (1), R represents a hydrocarbon group having 1 to 30 carbon atoms, and m is an integer of 2 to 60.)
In particular, a polyether skeleton in which R is a hydrocarbon group having 1 to 10 carbon atoms is suitable because it has a remarkable effect of increasing the delay time of the photocationic polymerization composition of the present embodiment.

  The monofunctional epoxy compound having one epoxy group in one molecule as the component (B) is a compound having one functional epoxy group in one molecule.

  The component (B) includes at least one of a monofunctional epoxy compound (B1) having a polyether skeleton in one molecule and a monofunctional epoxy compound (B2) having no polyether skeleton in one molecule.

  The monofunctional epoxy compound (B1) is polyethylene glycol monoglycidyl ether, polypropylene glycol monoglycidyl ether, polytetramethylene glycol monoglycidyl ether, or the like. A monofunctional epoxy compound (B1) can be used individually by 1 type from the above, or can use 2 or more types together.

  Monofunctional epoxy compounds (B2) are alkyl glycidyl ether, phenyl glycidyl ether, para tertiary butyl phenyl glycidyl ether, cresyl glycidyl ether, biphenyl glycidyl ether, glycol glycidyl ether, alkylphenol glycidyl ether, cyclohexene oxide, fatty acid glycidyl ester, etc. is there. A monofunctional epoxy compound (B2) can be used individually by 1 type from the above, or can use 2 or more types together.

  The component (C), a photocation generator (photocation polymerization initiator), generates a strongly acidic chemical species when irradiated with active energy rays such as ultraviolet rays and visible light, and epoxy groups (and in some cases). , An oxetane group). Such a photocation generator is not particularly limited, and may be, for example, an ionic photoacid generator or a nonionic photoacid generator. As the photocation generator, an ionic photoacid generator or a nonionic photoacid generator can be used alone, or an ionic photoacid generator and a nonionic photoacid generator can be used in combination.

  Examples of the ionic photoacid generator include onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts, and organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes. An ionic photo-acid generator can be used individually by 1 type from the above, or can use 2 or more types together.

  Nonionic photoacid generators include nitrobenzyl esters, sulfonic acid derivatives, phosphoric acid esters, phenol sulfonic acid esters, diazonaphthoquinone, N-hydroxyimidophosphonate, and the like. A nonionic photo-acid generator can be used individually by 1 type from the above, or can use 2 or more types together.

  The oxetane compound as component (D) is a curing accelerator that improves the steepness of curing of the photocationic polymerization composition. Curing steepness refers to the property that the curing rate (viscosity increase per unit time) of the photocationic polymerization composition rapidly increases in a short time, and the time until completion of curing is increased. Examples of such oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 2-ethylhexyloxetane, xylylenebisoxetane, 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane, and the like. It is. One oxetane compound can be used alone from the above, or two or more oxetane compounds can be used in combination.

  The elastomer as the component (E) changes the physical properties and chemical properties of the cured product of the photocationic polymerization composition. That is, the cured product of the photocationic polymerization composition containing an elastomer has a physical property such as an improvement in strength, a decrease in elastic modulus, and an increase in elongation rate, compared with a cured product of a photocationic polymerization composition that does not contain an elastomer. Changes in characteristics occur. In addition, the cured product of the cationic photopolymerization composition containing the elastomer has a polar group in the elastomer that adheres to the adherend (first member 1 described later), compared to the cured product of the cationic photopolymerization composition that does not contain the elastomer. And chemical interaction with the second member 2) or chemical property changes such as formation of a chemical bond with the adherend by a cationically polymerizable substituent in the elastomer occurs. When such a change in chemical characteristics occurs, the adhesion (adhesive strength) between the cured product of the photocationic polymerization composition and the adherend may be improved.

  The elastomer is formed of various polymer substances such as polyolefin, polystyrene, polyester, polyurethane, and silicone. These elastomers may be modified with highly polar substituents such as carboxyl groups, hydroxyl groups, cyano groups, thiol groups, and amino groups, or modified with cationically polymerizable substituents such as epoxy groups or oxetane groups. Then, it is more preferable. This is because the modified elastomer may improve the physical characteristics and chemical characteristics as compared with the case where the modified elastomer is not modified. One type of elastomer can be used alone, or two or more types can be used in combination.

  The form of the elastomer in the photocationic polymerization composition is not particularly limited, and may be a particle, may be in a state dissolved in the component (A) or (B), or may be in a dissolved state with the particle. Both forms may coexist.

  The cationic photopolymerization composition is prepared by containing the component (A), the component (B), the component (C), and the component (D). Moreover, the photocationic polymerization composition of this embodiment is prepared by containing (E) component in (A) component, (B) component, (C) component, and (D) component as needed. . Furthermore, the photocationic polymerization composition of the present embodiment contains one or both of the polyfunctional epoxy compound (A1) and the monofunctional epoxy compound (B1).

  The blending ratio of the component (A) and the component (B) when preparing the photocationic polymerization composition is a mass ratio and is in the range of (A) component: (B) component = 90: 10 to 30:70. . Although the delay time of curing of the cationic photopolymerization composition varies depending on the blending amount and type of each component, in general, the smaller the component (B), the shorter the delay time and vice versa. The cure delay time is increased.

  The “delay time” refers to the time during which the photocationic polymerization composition is kept in a liquid state after being irradiated with active energy rays. In this case, “liquid” means a state in which the viscosity of the photocationic polymerization composition is 50000 Pa · s or less. “Curing” is a state in which the viscosity of the photocationic polymerization composition is greater than 50000 Pa · s. When the delay time is long, application of the cationic photopolymerization composition and adhesion of members by the cationic photopolymerization composition become possible, and it can be said that the usable time of the cationic photopolymerization composition is long and the handling property is excellent.

  If the amount of the monofunctional epoxy compound as the component (B) is less than the above range, it may be difficult to secure a delay time necessary for bonding, etc., and it may be difficult to obtain a sufficient pot life, which may reduce the handleability. . If the amount of the monofunctional epoxy compound as component (B) is larger than the above range, sufficient three-dimensional crosslinking is not likely to occur in the cured product of the cationic photopolymerization composition, so the strength of the cured product of the cationic photopolymerization composition is reduced. However, for example, it may be difficult to obtain a sufficient adhesive force.

  A more preferable range of the ratio of the component (A) to the component (B) is a mass ratio, and the range is (A) component: (B) component = 85: 15 to 40:60. A more preferable range of the blending ratio of the component (A) and the component (B) is a mass ratio, and the range is (A) component: (B) component = 80: 20 to 50:50.

  Further, the total amount of the epoxy compound having a polyether skeleton in one molecule contained in both or one of the component (A) and the component (B) (that is, the polyfunctional epoxy compound (A1) and the monofunctional epoxy compound (B1 The total amount of) is preferably in the range of 0.01 to 90% by mass with respect to the total amount of the epoxy compounds of the component (A) and the component (B). More preferably, the total amount of the epoxy compound having a polyether skeleton in one molecule included in both or one of the component (A) and the component (B) is the epoxy compound of the component (A) and the component (B). It is preferable that it is the range of 0.1-30 mass% with respect to the total amount of.

  (C) It is preferable that the compounding quantity of a component is a ratio of 0.01-10 mass parts with respect to 100 mass parts of total mass of (A) component and (B) component. If the proportion of the photocation generator is less than 0.01 parts by mass with respect to 100 parts by mass of the total mass of the components (A) and (B), the photocationic polymerization composition is not sufficiently polymerized. An uncured part may remain. When the proportion of the photocation generator is more than 10 parts by mass with respect to 100 parts by mass of the total mass of the component (A) and the component (B), the curing reaction of the photocationic polymerization composition becomes too fast and delayed. The curability may be lost, or the deep curability may deteriorate (becomes a non-uniform cured product).

  (D) It is preferable that the compounding quantity of a component is the range of 0.01-30 mass% with respect to the total amount of (A) component and (B) component. Thereby, the rise behavior of the viscosity at the time of hardening of a photocationic polymerization composition tends to become steeper. For this reason, when the photocationic polymerization composition is used as an adhesive, the curing time at room temperature after bonding can be shortened, leading to a reduction in tact time, and no positional displacement occurs early after bonding. Therefore, the next process can be started immediately, and the production efficiency can be greatly improved. When the blending amount of the component (D) is 0.01% by mass or less, the above effect is small, and when it is 30% by mass or more, the curing is too fast and it is difficult to secure the delay time required for bonding.

  When a photocationic polymerization composition contains (E) component, the compounding quantity of (E) component is 0.1-50 mass% with respect to the total amount of (A) component and (B) component. Preferably there is. If the compounding quantity of (E) component is this range, it will become easy to change the said physical characteristic and chemical characteristic of the hardened | cured material of a photocationic polymerization composition. That is, when the blending amount of the component (E) deviates from the above range, it becomes difficult to change the physical characteristics and chemical characteristics of the cured product of the photocationic polymerization composition.

  The method for preparing the cationic photopolymerization composition includes, for example, the (A) component, the (B) component, the (C) component, the (D) component, and, if necessary, the (E) component in a predetermined mass ratio. Then, after adjusting the temperature to 20 to 100 ° C., the mixture is stirred with a homodisper or the like until uniform. Thereby, a substantially transparent liquid photocationic polymerization composition is obtained.

  The cationic photopolymerization composition of the present embodiment maintains a liquid state immediately after irradiation with active energy rays and exhibits delayed curability that cures after a certain period of time. If such a photocationic polymerization composition is an adhesive, a delayed curing adhesive can be obtained. The delayed-curing type adhesive here refers to an adhesive having a time allowance for bonding the members together by maintaining the liquid state for a certain period of time after applying the energy necessary to start the curing reaction (ie, usable adhesive). It is an adhesive having a long time), and further, the curing reaction proceeds sufficiently without additional energy such as light and heat after bonding, and the curing is completed. The delayed-curing adhesive is activated only when irradiated with active energy rays, and a curing reaction is started. Therefore, it is hardly cured unless irradiated with an active energy ray, and is different from an adhesive that spontaneously cures in a normal environment, such as a solvent-type adhesive or a cyanoacrylate instantaneous adhesive.

In the photocationic polymerization composition of the present embodiment, the delay time varies depending on the composition of the photocationic polymerization composition, the irradiation intensity of active energy rays, the temperature of the photocationic polymerization composition, and the like. Assuming an actual bonding step using the photocationic polymerization composition of this embodiment as an adhesive, an active energy ray having a wavelength of 365 nm is irradiated at an irradiation dose of 50 mJ / cm ² or more in an atmosphere at a temperature of 25 ° C. After that, it is liquid for 5 seconds or more and 60 minutes or less, and then it is preferably cured within 12 hours. It is preferable to adjust the composition of the photocationic polymerization composition so as to achieve such properties.

If the photocationic polymerization composition of this embodiment is maintaining the liquid state after irradiation of active energy rays for less than 5 seconds, there is little time for bonding and it is not realistic. If the liquid state is maintained for more than 60 minutes, there is a high possibility that the position of the member will shift, and the time until the curing is completed will be long. In addition, it is considered that the time from the completion of the curing until the sufficient strength is exhibited is within 12 hours from the viewpoint of productivity. Of course, the shorter, the better. Moreover, about the irradiation amount of an active energy ray, 50 mJ / cm < ² > or more is appropriate. If the irradiation amount is less than this, the amount of the cation species generated by irradiation with active energy rays is too small, and the polymerization reaction may be stopped midway, resulting in poor curing. Further, since the polymerization reaction becomes faster when the irradiation amount of the active energy ray is large, the delay time and the curing completion time are shortened. There is also an effect of temperature. In the cationic polymerization of epoxy compounds, the amount of cationic species generated has a positive correlation with the amount of irradiation of active energy rays, but basically light is not involved in the polymerization reaction and is influenced by temperature. Therefore, the polymerization reaction is slow at low temperatures, and the polymerization reaction is fast at high temperatures. If this is applied and active energy rays are irradiated at a low temperature before bonding, the delay time can be increased. Moreover, it is also possible to shorten the curing time by heating after bonding.

  The mechanism by which the cationic photopolymerization composition of the present embodiment exhibits delayed curability is as follows. When the photocation generator absorbs active energy rays, cations are generated, and the cation polymerization of the monofunctional epoxy compound of the component (B), which is contained in the photocationic polymerization composition in a large amount, is initiated. These monofunctional epoxy compounds are cationically polymerized to increase the molecular weight. However, since the molecule has only one epoxy group, the molecule grows linearly without being three-dimensionally cross-linked. Therefore, at the initial stage of the reaction, the viscosity hardly increases and the liquid state is maintained. In practice, the polymerization reaction is proceeding, but the viscosity does not substantially increase and the liquid state is maintained, so that it appears almost unchanged from that before irradiation with active energy rays. Thereafter, when the polymerization further proceeds and the molecular weight increases, the molecular chains of the polymer of the monofunctional epoxy compound are entangled with each other, thereby increasing the viscosity. In addition, a polyfunctional epoxy compound having two or more epoxy groups in one molecule of the component (A) reacts to form a three-dimensional crosslinked structure, and finally curing is completed. In this mechanism, the active energy ray is only used to generate a cation from the photocation generator and start the polymerization reaction. Thereafter, the polymerization reaction proceeds spontaneously even if the irradiation of the active energy ray is stopped. Go. As a result, it exhibits a behavior of delayed curing in which the liquid state is maintained for a certain period of time after irradiation with the active energy ray, and then curing is completed without irradiation or heating of the active energy ray.

  As with the photocationic polymerization composition of the present embodiment, the photocurable resin composition that exhibits the behavior of a delayed curable adhesive that maintains a liquid state for a certain period of time after irradiation with active energy rays and then completes curing, It has been known so far (see Document 1). This is a technique in which the added polyether-based or thioether-based delayed curing agent traps the cationic species generated from the photocation generator upon irradiation with light and delays the start of the cationic polymerization reaction. The photocationic polymerization composition of this embodiment is different from the technique of Patent Document 1 in that it controls not the initiation reaction but the subsequent polymerization reaction (growth reaction). Moreover, since the technique of patent document 1 and the photocationic polymerization composition of this embodiment are not contradictory techniques, it is estimated that more effective delayed-hardening property is exhibited by combining.

  Further, in the cationic photopolymerization composition of the present embodiment, at least one of the component (A) and the component (B) is an epoxy compound having a polyether skeleton in one molecule (that is, a polyfunctional epoxy compound (A1) and a single component). Since it contains a functional epoxy compound (B1)), when an epoxy compound having a polyether skeleton and a cation are present in one molecule, the polyether skeleton is changed according to the change in the concentration of the released cation according to the principle of Le Chatelier. And cation association / release occurs. That is, when a large amount of cations are present in the photocationic polymerization composition, the equilibrium is inclined toward the association side, and the free cations in the photocationic polymerization composition are reduced. On the other hand, when free cations are reduced, the equilibrium is inclined to the free side, and free cations can be supplied into the photocationic polymerization composition.

  In general, when a photocation generator absorbs an active energy ray, it generates a cation, and this cation acts on the epoxy compound to initiate cationic polymerization. At this time, if the amount of cations generated is large, the polymerization reaction is fast, and if it is small, the polymerization reaction is slow.

  In the delayed curing type photocationic polymerization composition of this embodiment having an epoxy compound and a photocation generator as essential components, a large amount of cations are generated from the photocation generator immediately after irradiation with active energy rays. Some of the generated cations polymerize the epoxy compound by a reaction with the epoxy compound, while the remaining cations associate with the polyether skeleton and do not polymerize the epoxy compound. After that, when the cation that polymerizes the epoxy compound is deactivated by the termination reaction, the amount of cation in the photocationic polymerization composition decreases, so that the equilibrium of the polyether skeleton and cation liberation / association is inclined to the free side, and photocationic polymerization. Cations are newly supplied into the composition, and the polymerization reaction of the epoxy compound is continued.

  The liberation / association of the polyether skeleton and the cation proceeds independently of irradiation with active energy rays. For this reason, even after the irradiation with the active energy ray is completed, the cation is supplied as the cation concentration is decreased due to the deactivation, so that the polymerization reaction of the epoxy compound proceeds. As a result, the photocationic polymerization composition of the present embodiment maintains a liquid state for a certain period of time after irradiation with active energy rays, and then the delayed curable behavior that completes curing without irradiation or heating with active energy rays. Indicates. The cationic photopolymerization composition of the present embodiment has a gentle increase in viscosity immediately after the start of the reaction (immediately after irradiation with the active energy ray), and the delay time becomes long. As a result, it is possible to take a long time (working time) for bonding the members, and the handleability is excellent.

  Moreover, since the polyether skeleton is incorporated in the molecule of the epoxy compound which is the component (A) or the component (B), the cationic photopolymerization composition of the present embodiment has a polysiloxane after curing of the cationic photopolymerization composition. It is possible to reduce the bleeding out of the ether skeleton portion (seepage or protrusion of the photocationic polymerization composition on the surface of the cured product). If a compound having a polyether skeleton instead of an epoxy compound is blended in the photocationic polymerization composition, the compound having the polyether skeleton becomes difficult to be incorporated into the cured product of the photocationic polymerization composition. A compound having a polyether skeleton is easily detached from the dimensional network structure. Accordingly, bleeding out of the compound having a polyether skeleton is likely to occur.

  In the photocationic polymerization composition of the present embodiment, the change mechanism of the curing behavior due to the addition of the oxetane compound is estimated as follows. When the molecular weight of an epoxy compound or oxetane compound increases due to a growth reaction, the polymerization may stop substantially because the cation species present at the end of the molecular chain moves into the molecular chain due to chain transfer. . It is known that such chain transfer is likely to occur in the case of epoxy compounds and is relatively difficult to occur in the case of oxetane compounds (Toho Synthetic Research Annual Report TREND 1999 No. 2 "Application of Oxetane Compounds to Photocationic Curing Systems" "reference). For this reason, when the cationic photopolymerization composition does not contain an oxetane compound, the thickening of the cationic photopolymerization composition is moderated due to the influence of polymerization termination of the epoxy compound accompanying chain transfer, whereas the cationic photopolymerization composition When the product contains an oxetane compound, it is considered that the polymerization termination due to chain transfer hardly occurs, so that the photocationic polymerization composition increases the molecular weight smoothly and exhibits a steep increase in viscosity. That is, by including the polyether skeleton and the oxetane compound, the initial increase in viscosity is moderated, and after a certain period of time after irradiation with active energy, the liquid is kept in a liquid state, and then, after the predetermined period of time, a sharp increase in viscosity is caused by the effect of the oxetane compound. As a result, a sufficient bonding strength capable of working is generated in the subsequent steps while securing a bonding time for a certain time.

(Description of manufacturing method of portable information terminal)
In manufacturing the portable information terminal 100, an adhesive placement process, an irradiation process, a bonding process, and a curing process are sequentially performed.

In the adhesive placement step, the uncured adhesive 3 is provided on at least one of the housing 10 and the cover panel 20. In FIG. 7, the uncured adhesive 3 is provided on the adhesive surface 10a of the housing 10, but not limited thereto, the uncured adhesive 3 may be provided on the adhesive surface 20 of the cover panel 20, or The uncured adhesive 3 may be provided on both the adhesive surface 10a and the adhesive surface 20a. Arbitrary methods, such as application | coating and printing, are employ | adopted as a means to provide the uncured adhesive agent 3. The adhesive 3 of uncured, for example, is provided in an amount of 5 to 50 mg / cm ^2.

In the irradiation step, the active energy rays 4 are irradiated to the uncured adhesive 3 after the adhesive placement step. The active energy ray 4 is ultraviolet light. Curing of the uncured adhesive 3 is started by irradiation with the active energy ray 4. Further, by this irradiation step, the active energy ray 4 in an amount necessary for the uncured adhesive 3 to be cured to the bonded portion 5 is irradiated. For example, an ultraviolet lamp is used for irradiation with the active energy ray 4. The irradiation amount of the active energy ray 4 can be set to, for example, 50 to 3000 mJ / cm ² . In particular, when the adhesive 3 is colored, the transmittance tends to be low. In order to obtain sufficient curing up to the deep part of the applied adhesive 3, it is desirable to set it to 1000 to 3000 mJ / cm ² .

  In the bonding process, the housing 10 and the cover panel 20 are bonded to each other through the uncured adhesive 3 after the irradiation process. In this case, as shown in FIG. 8, the cover panel 20 provided with the display panel 6 is brought closer from the front side of the housing 10. Then, the cover panel 20 is fitted (fitted) into the opening of the housing 10, and the uncured adhesive 3 is interposed between the adhesive surface 10a and the adhesive surface 20a.

  In the curing process, the adhesive 3 is cured after the bonding process, and the casing 10 and the cover panel 20 are bonded with the cured adhesive 3 (adhesive portion 5). Curing of the adhesive 3 in the curing process is performed by the active energy rays 4 irradiated in the irradiation process. Therefore, there is almost no need to irradiate the active energy ray 4 in the curing process. Even when the casing 10 and the decorative printing unit 21 do not pass the active energy ray 4 (for example, when the ultraviolet ray transmittance is 5% or less), the curing of the adhesive 3 proceeds.

  The adhesive 3 used in the method for manufacturing the portable information terminal 100 as described above is cured by the active energy ray 4 and is in a liquid state from the adhesive arranging step to after the bonding step. It is a delayed curing type adhesive that cures in the curing process. By using the photocationic polymerization composition as described above as a delayed-curing type adhesive, fine wire coating (for example, 0.2-2.0 mm thin wire coating) is possible, and desired adhesive strength (for example, 1 MPa or more) Adhesive strength) is ensured, and the tact time can be shortened (for example, the tact time can be shortened from several minutes to several hours).

  In the above-described adhesive placement step, as shown in FIG. 9A, the adhesive 3 can be applied in a linear form to the adhesive surfaces 10a and 20a from the nozzle 200, and in this case, as shown in FIG. 9B. In addition, in the cross section in the direction orthogonal to the longitudinal direction of the adhesive 3, the dimension H in the direction protruding from the bonding surfaces 10a and 20a of the adhesive 3 is 1/2 or more of the dimension W in the direction orthogonal to the protruding direction. It is preferable that That is, when bonding is performed with an adhesive width of 1 mm or less, the height dimension H of the adhesive 3 from the adhesive surfaces 10a and 20a is not less than 1/2 of the width dimension W of the adhesive 3 (H ≧ 1 / 2W). It is preferable that More preferably, the relationship of H ≧ 3 / 4W is satisfied. By setting the cross-sectional shape of the adhesive 3 supplied to the adhesive surfaces 10a and 20a in this way, the adhesive 3 is easily spread to a uniform thickness in the bonding process of the housing 10 and the cover panel 20, and the adhesive portion 5 can be stably secured (the width of the portion in contact with the bonding surfaces 10a and 20a). In the adhesion of 1 mm width or less, securing the adhesion width stably means securing a small adhesion area from the beginning, and the adhesion thickness is very important for shock absorption. Therefore, the adhesive strength between the housing 10 and the cover panel 20 is increased. The viscosity and thixotropy of the adhesive 3, the application speed of the adhesive 3, the discharge pressure (discharge air pressure), and the like can be adjusted so that the adhesive 3 has the predetermined cross-sectional shape as described above. In adjusting the viscosity and thixotropy of the adhesive 3, for example, an appropriate amount of fumed silica can be blended. Further, when the protrusion 15 is formed on the adhesive surface 10 a, the protrusion 15 is covered with the adhesive 3. Thereby, even if the protrusion 15 is formed, the adhesive 3 can be sufficiently brought into contact with the adhesive surfaces 10a and 20a to be cured, and the adhesive strength between the housing 10 and the cover panel 20 is increased.

  The adhesive 3 is preferably applied linearly over the entire length of the adhesive surface 10a of the housing 10. In this case, a frame that surrounds the opening of the housing 10 with the adhesive 3 can be formed. Moreover, it is preferable to apply | coat the adhesive agent 3 continuously like a one-stroke drawing. In this case, when the adhesive has a waterproof function due to hydrophobicity or the like, the casing 10 and the cover panel 20 are bonded to each other with almost no gap by forming the frame-shaped adhesive portion 5 that surrounds the opening of the casing 10. The waterproof property of the portable information terminal 100 can be improved. In order to improve the waterproof property of the portable information terminal 100, it is conceivable to provide a packing between the housing 10 and the cover panel 20 without forming the adhesive portion 5, but the portable information terminal 100 is small. If it is changed, it is necessary to reduce the packing, and sufficient waterproofness may not be ensured.

  In order to ensure the adhesive strength and waterproofness of the housing 10 and the cover panel 20 and further to ensure the curability of the adhesive 3, the width dimension W of the adhesive 3 is preferably 0.2 to 1 mm.

  In supplying the adhesive 3 in a predetermined shape as described above, the adhesive 3 preferably has a viscosity of 30 to 800 Pa · s and a thixo index of 1.5 to 15.0.

  Hereinafter, the present invention will be specifically described by way of examples. In addition, the material used in the Example is an example, Comprising: The thing comprised using the other material based on the material with the characteristic shown by this specification is included in this invention.

Example 1
As the adhesive, a delayed-curing type that maintains a liquid state immediately after irradiation with active energy rays and cures after a lapse of a certain time was used. As this adhesive, XV7811A2 manufactured by Panasonic Corporation was used, and the viscosity was adjusted to 100 Pa · s and the thixo index was 4.0.

  XV7811A2 is 50 parts by mass of bisphenol A type bifunctional epoxy resin jER828 (trade name, manufactured by Mitsubishi Chemical Corporation), 30 parts by mass of aromatic monofunctional epoxy resin mp-CGE (trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd.), polyether Skeletal-containing monofunctional epoxy resin EX145 (manufactured by Nagase ChemteX, trade name) 20 parts by mass, aromatic sulfonium salt photocation generator SP170 (made by ADEKA, trade name) 3 parts by weight, carboxyl group-containing nitrile butadiene rubber XER32C It is composed of 5 parts by mass (trade name, manufactured by JSR) and 2 parts by mass of epoxy group-containing silicone elastomer powder EP2601 (trade name, manufactured by Toray Dow Corning).

This delayed-curing type adhesive is activated by irradiating with 100 mJ / cm ² of ultraviolet rays from an LED type UV light source (LC-L5 manufactured by Hamamatsu Photonics Co., Ltd.) having a center wavelength of 365 nm. After 30 minutes, the viscosity becomes 50000 Pa · s or more and is cured to form an adhesive part. The bonded part exhibits a shear bond strength of 1 MPa or more.

  The casing was molded for cellular phones using polycarbonate (Teijin Panlite). The cover panel has a tempered glass plate that is durable against scratches and the like as a panel main body, and a decorative printing layer is provided on the panel main body so that an adhesive portion is not visible. A display panel (liquid crystal panel) was bonded to the cover panel so as to exclude the decorative printing section. The decorative print layer does not allow the interior to be seen through the peripheral edge of the cover panel and the adhesive state is not visible, so that the user can not see the adhesive part and can supply products with excellent design and design. . On the other hand, the transmittance of the adhesive surface of the cover panel in the ultraviolet to visible light region is significantly reduced to 0 to 5%. The light transmittance of the decorative print layer of Example 1 was 0%. The bonding surface of the housing is formed with a width of 0.5 mm so that the bonding width is as thin as possible in order to secure an effective use area of the display panel.

  Next, the adhesive placement process, the irradiation process, the bonding process, and the curing process were sequentially performed using the adhesive, the casing, and the cover panel (with a display panel).

  The adhesive was applied to the bonding surface of the casing (surface roughness Ra was 2 nm) with a coating device. As a coating device, a dispensing robot (SM-200DS manufactured by Musashi Engineering) and a pulse air dispenser (ML-5000X2 manufactured by Musashi Engineering) were used. At this time, the adhesive was applied with a height dimension H of 0.25 mm and a width dimension W of 0.4 mm by adjusting the discharge air pressure and the coating speed. The adhesive was applied in a frame shape so as to surround the opening of the housing over the entire circumference.

Next, the applied adhesive was irradiated with ultraviolet rays as active energy rays. At this time, as an ultraviolet light source, LC-L5 (linear 365 nm UV-LED light source) manufactured by Hamamatsu Photonics was used, and the irradiation amount was 100 mW / cm ² × 1 second = 100 mJ / cm ² .

  And the cover panel was bonded together within 1 minute after ultraviolet irradiation. It left still for 30 minutes after bonding, the adhesive agent was hardened, and the adhesion part was formed. Thereafter, it was confirmed that when a force of 100 N was applied as a force for peeling the casing and the cover panel in a direction perpendicular to the bonding surface (perpendicular), the casing and the cover panel were not peeled off. When force was applied up to 120 N, the casing and the cover panel could be peeled off.

  The above adhesive contains a polyfunctional epoxy compound having two or more epoxy groups in one molecule and a monofunctional epoxy compound having one epoxy group in one molecule, and has a polyether skeleton. Or it has delayed-hardening property by containing a monofunctional epoxy resin. In addition, the adhesive contains an oxetane compound, which causes a steep increase in viscosity after bonding, and can be cured in a short time of 30 minutes. Using such a delayed-curing and ultraviolet-curing adhesive, it was possible to bond the cover panel and the housing that hardly transmit light to the adhesive surface. Further, since the adhesive had a viscosity of 100 Pa · s and a thixo index of 4.0, the shape after application was not easily broken, and the adhesive width (area) could be stably secured.

  When the obtained portable information terminal was immersed in water having a depth of 1 m, water did not enter inside the case, and the inside of the case could be waterproofed. After this test, the cover panel was peeled off with a great force. As a result, an adhesive part was formed with a height of 0.2 mm and a width of 0.5 mm, and the adhesive surface was uniformly adhered over the entire circumference. In addition, even after the adhesive is crushed by bonding, the shape of the adhesive is good, and the adhesive does not penetrate into other electronic components inside, making it possible to achieve a very good adhesive state. The thickness of the adhesive was also uniform over the entire circumference of the housing.

(Example 2)
In Example 1, plasma cleaning treatment was performed on the bonding surface of the housing and the bonding surface of the cover panel, and a fine uneven structure was added to the surface of the bonding surface. Other configurations were the same as in Example 1 to manufacture a portable information terminal. A plasma cleaner PDC200 manufactured by Yamato Scientific was used for the plasma cleaning treatment, Ar gas was introduced, and the treatment was performed at 200 W for 2 minutes. After bonding the housing and the cover panel, the adhesive was cured by standing for 30 minutes to form an adhesive part. Thereafter, a force of 150 N was not applied as a force for peeling the casing and the cover panel in a direction perpendicular to the bonding surface. By making the bonding surface uneven by plasma cleaning, the housing and the cover panel could be firmly bonded.

  When the obtained portable information terminal was immersed in water having a depth of 1 m, water did not enter inside the casing, and the inside of the casing could be waterproofed. Even if a rugged structure with a surface roughness Ra of 60 nm and a concavo-convex height of 100 nm or less is formed on the bonding surface, the adhesive adheres along the shape, so that waterproofness can be ensured, and the adhesion strength is also flat. Compared to that, it was able to be dramatically increased.

FIG. 11 shows an atomic force microscope photograph obtained by photographing the bonding surface of the housing in Example 1. Further, FIG. 12 shows an atomic force microscope photograph obtained by photographing the bonding surface of the housing in Example 2. In Example 2, the height difference of the unevenness of the adhesion surface is larger than that in Example 1 due to the plasma cleaning process (Example 3).
In Example 2, as shown in FIGS. 10A and 10B, a protrusion 15 having a height h of 0.1 to 0.15 mm and a width w of 0.1 to 0.2 mm is added to the bonding surface 10 a of the housing 10. . The protrusion 15 was formed at the same time as the casing 10 was molded. As shown in FIG. 10C, the adhesive 3 was applied so that the height dimension H was 0.3 mm and the width dimension W was 0.4 mm. Other configurations were the same as in Example 2 to manufacture a portable information terminal. Thereafter, even when 150 N was applied as a force for peeling the casing and the cover panel in a direction perpendicular to the bonding surface, the casing and the cover panel were not peeled off.

  When the obtained portable information terminal was immersed in water having a depth of 1 m, water did not enter inside the casing, and the inside of the casing could be waterproofed. Even if there are protrusions on the adhesive surface, it is possible to wrap both the protrusions and the concavo-convex structure with adhesive by applying an adhesive with high shape retention at a width and width of the protrusions, which also ensures waterproofness. I was able to. In addition, by providing this protrusion, it has become possible to prevent the appearance of a counterfeit product that is a copy of the housing structure.

Example 4
The adhesive used in Example 1 contained a black dye. In the adhesive containing no dye, the visible light transmittance is about 40% on the long wavelength side, but the transmittance decreases as the wavelength becomes shorter, and decreases to 10% at 400 nm. The ultraviolet ray irradiated in the irradiation step was 365 nm, and the adhesive containing no dye at that wavelength had a transmittance of 8%. Adjustment of the content of the dye is such that after the adhesive containing the dye is applied to the adhesive surface, the transmittance of ultraviolet light having a wavelength of 365 nm in the thickness direction (from the top to the bottom) of the adhesive is about 1%. did. When the portable information terminal was manufactured in the same manner as in Example 1 for other configurations, the case and the cover panel could be bonded together as in Example 1.

  By adding a black color to the adhesive and bonding the housing and the cover panel, it becomes difficult to see even if the adhesive part protrudes from the gap between the cover panel and the housing, and the design is improved. I was able to. Further, the adhesive has a high shape retaining property, and even when the adhesive is crushed and bonded, the casing and the cover panel can be bonded to each other with an adhesive portion having a uniform width of 0.5 mm. Therefore, the thickness of the bonding portion is perpendicular to the bonding surface, and it is difficult to transmit visible light in the horizontal direction, so that the liquid crystal panel backlight or the like tends to leak from the gap between the cover panel and the housing. It became possible to block the light. As a result, it is possible to reduce or prevent light from leaking through the adhesive portion when the user operates the portable information terminal (mobile phone) in a dark place.

  By making the content of the dye with respect to the total weight of the adhesive 0.005 wt% or more, the adhesive can be visually recognized as black. When the dye is less than 1 wt%, the adhesive transmits ultraviolet light and blocks visible light. I was able to. In addition, with 1 wt% of the dye, it was difficult to transmit ultraviolet rays to the lower part of the adhesive even when the height of the adhesive was 0.05 mm. For this reason, the range of the dye content is preferably 0.005 to 1 wt%. Furthermore, when the transmittance of visible light (400 to 680 nm) at the bonded portion was 5% or less, the leakage of light from the backlight was greatly reduced and could be almost blocked. However, when the ultraviolet light with a wavelength of 365 nm can reach only 1% to the bottom surface of the adhesive (interface with the adhesive surface), the adhesive on the bottom surface may be uncured and may not be sufficiently bonded. Accordingly, it is preferable that the transmittance of ultraviolet light with a wavelength of 365 nm to the bottom surface of the adhesive applied to the adhesive surface is 1% or more.

(Example 5)
Instead of the black dye used in Example 4, a light absorbing material that absorbs a specific wavelength was used. This light absorbing material was adjusted so as to intensively absorb the wavelength corresponding to the emission wavelength of the white LED of the backlight used in a liquid crystal panel or the like. Specifically, a white LED is used as the backlight LED, but it is visually recognized as white by combining light emitted from light sources of 450 nm, 540 nm, and 640 nm. Therefore, 450 nm light, which is the emission wavelength of the LED, is absorbed using Yamada Chemical Co., Ltd. FDB-004, 540 nm light is absorbed using the company's FDG-003, and a wavelength around 640 nm is made by Sanyo Dye Co., Ltd. Three types of light absorbing materials were blended so as to be absorbed using O-270. FDB-004 can absorb light of 450 ± 50 nm, FDG-003 can absorb light of 540 nm ± 40 nm, and O-270 can absorb light of ± 40 nm efficiently. That is, it becomes possible to efficiently absorb the light emission wavelength of the LED and to perform coloring that does not absorb much at the wavelength of 365 nm of the active energy ray.

  The above three types of light-absorbing materials can be contained in an adhesive by 0.003 wt%, and the visible light can be efficiently absorbed by the bonded portion, and the visible light transmittance can be suppressed to 5% or less. It was. The adhesive part at this time was visually recognized as black. Further, these light absorbing materials absorb only a specific wavelength and do not absorb much light in other wavelength bands, and therefore do not absorb light having a wavelength of 365 nm, which is an active energy ray. For this reason, it becomes possible to efficiently cure the adhesive by ultraviolet rays while blocking visible light, and even if the height dimension H of the adhesive applied to the adhesive surface is 0.25 mm, It was possible to transmit 5% or more of 365 nm light to the lower surface, and to suppress the visible light transmittance to 5% or less.

(Example 6)
An adhesive was prepared by adding 20% by mass of an oxetane compound (OXMA, manufactured by Ube Industries) to the delayed curing UV adhesive used in Example 1 with respect to the total amount of the epoxy compound. Then, in the same manner as in Example 1, the cover panel was bonded to the housing within 1 minute after the ultraviolet irradiation. The adhesive after irradiation was hardly observed to increase in viscosity. After bonding, the adhesive was allowed to stand for 20 minutes to cure the adhesive, and the force to peel off the casing and the cover panel in a direction perpendicular to the adhesive surface was 100N. In addition, it was confirmed that the casing and the cover panel were not peeled off. This is thought to be due to the addition of the oxetane compound to the adhesive, which resulted in more rapid curing and the adhesion exceeding 100 N was realized in a short time. In addition, the same effect was able to be acquired also when using OXT-221, 121, 212, 101 by Toagosei Co., Ltd. as an oxetane compound.

(Comparative Example 1)
A portable information terminal was manufactured in the same manner as in Example 1 by using an ultraviolet curable resin 8833 manufactured by Kyoritsu Chemical as an adhesive.

Since the adhesive had a low viscosity of 26 Pa · s, the height of the shape when applied was non-uniform when the height was 0.1 mm or less, and the adhesive was wet spread on the adhesive surface of the housing. When the ultraviolet rays were irradiated directly after the adhesive was applied, the surface was cured and the cover panel could not be bonded well. Moreover, when ultraviolet rays were irradiated after fitting the cover panel to the casing, the ultraviolet rays did not pass through the cover panel and the adhesive could not be cured. In addition, since the viscosity of the adhesive is low and spreads, it may flow into the light guide plate of the liquid crystal member and the product value may be significantly reduced. The irradiation amount of ultraviolet light with a wavelength of 365 nm irradiated for curing from the cover panel side was 500 mW / cm ² × 12 seconds = 60000 mJ / cm ² .

(Comparative Example 2)
A portable information terminal was manufactured in the same manner as in Example 2 using an ultraviolet curable resin 8833 manufactured by Kyoritsu Chemical as an adhesive.

(Comparative Example 3)
A portable information terminal was manufactured in the same manner as in Example 3 using an ultraviolet curable resin 8833 manufactured by Kyoritsu Chemical as an adhesive.

(Comparative Example 4)
A portable information terminal was manufactured in the same manner as in Example 1 using a double-sided adhesive tape (Nitto Denko No. 57115B) instead of the adhesive.

  No. 57115B is a double-sided pressure-sensitive adhesive tape in which an acrylic pressure-sensitive adhesive layer is formed on both surfaces of a polyolefin-based foam film, and is widely used for assembling mobile phones.

  It was not possible to cut out with a width of 0.5 mm so as to match the width of the bonding surface of the housing. Since it was cut out at a width of 1 mm, it was possible to bond it by widening and bonding the bonding portion between the bonding surface of the housing and the bonding surface of the cover panel.

(Comparative Example 5)
A portable information terminal was manufactured in the same manner as Example 2 using a double-sided adhesive tape (Nitto Denko No. 57115B) instead of the adhesive.

  In this case, since the uneven surface is formed by performing the plasma cleaning process on the adhesive surface, the double-sided adhesive tape cannot be brought into close contact with the adhesive surface, and when the portable information terminal is immersed in water, It was confirmed that water had infiltrated, and the waterproofness could not be maintained.

(Comparative Example 6)
A portable information terminal was manufactured in the same manner as Example 3 using a double-sided adhesive tape (Nitto Denko No. 57115B) instead of the adhesive.

  In this case, since there is a protrusion on the adhesive surface, there is a gap between the double-sided adhesive tape and the adhesive surface at the protrusion, the cover panel tilts, and the housing and the cover panel can be bonded together accurately. There wasn't.

(Evaluation)
About Examples 1-3 and Comparative Examples 1-6, bonding property, drop impact property, and waterproofness were evaluated.

  As for the bonding property, “◯” was given when the casing and the cover panel were stuck together at an accurate position, and “X” was given when they were not stuck together at the exact position.

  As for the drop impact property, when the portable information terminal was dropped 100 times from a height of 70 cm, it was confirmed that the adhesive part of the casing and the cover panel was not peeled off. The thing was set as x.

  The waterproof property was marked with ○ when the portable information terminal was immersed in 1 m deep water and no water intrusion was observed inside the case, and x when water intruded.

  In the above embodiment, an adhesive having a viscosity of 100 Pa · s is used, but the viscosity may be further increased in order to further improve the shape retention. For example, silica powder # 100 manufactured by Maruto Co., Ltd. may be added, and the viscosity of the adhesive may be increased and adjusted to exceed 500 Pa · s. In this case, the shape after application hardly changes, but the application pressure of the pulse air dispenser becomes very high, so it is desirable to adjust it appropriately according to the capability of the adhesive application device. However, when the viscosity exceeds 800 Pa · s, it is difficult to apply with a commonly used pneumatic dispenser, and a special dispenser device such as a Mono pump is required.

  In the above embodiment, a delayed curable adhesive that cures at an ultraviolet wavelength of 365 nm is used. However, the adhesive is not limited to this, and is a delayed curable adhesive that cures at other wavelengths such as 350 nm and 320 nm. May be.

  In the above embodiment, the plasma cleaning process was performed for 2 minutes, and an uneven surface having a surface roughness Ra of 100 nm or less was formed. However, even if the plasma cleaning process time is changed as appropriate, the process is performed for 5 seconds to 5 minutes. good. If the treatment time is less than 5 seconds, it is difficult to form a concavo-convex structure on the adhesive surface, and an effect is likely to occur from 5 seconds or more. By extending the time of the plasma cleaning process, the concavo-convex structure is likely to be formed with a surface roughness Ra of 10 to 300 nm, and the concavo-convex parts may stick to each other and become larger in a processing time of 5 minutes or more. The influence of heat and the like is also increased, and the resin cover panel may be damaged greatly.

DESCRIPTION OF SYMBOLS 100 Portable information terminal 3 Adhesive 5 Adhesive part 6 Display panel 10 Case 10a Adhesive surface 15 Protrusion 20 Cover panel 20a Adhesive surface

Claims (12)

A housing for housing the display panel;
A cover panel for protecting the display panel;
A portable information terminal comprising an adhesive part for adhering the housing and the cover panel,
The portable information terminal is a cured product of an adhesive that is liquid immediately after irradiation with active energy rays and is cured after a predetermined time has elapsed. In claim 1,
A portable information terminal in which a dimension of the adhesive portion in a facing direction between an adhesive surface of the cover panel and an adhesive surface of the housing is 30 to 200 µm. In claim 1 or 2,
A portable information terminal, wherein at least one of an adhesive surface of the cover panel and an adhesive surface of the housing is an uneven surface. In any one of Claims 1 thru | or 3,
The housing has a protrusion on its adhesive surface,
The portable information terminal, wherein the adhesive portion is formed to cover the protrusion. In any one of Claims 1 thru | or 4,
The adhesive portion contains at least one of a dye and a pigment. In any one of Claims 1 thru | or 5,
The said adhesion part contains the light absorption material which absorbs the light of a specific wavelength, The portable information terminal. A housing for housing the display panel;
A cover panel for protecting the display panel;
A method of manufacturing a portable information terminal comprising an adhesive portion that bonds the housing and the cover panel,
The adhesive portion is liquid immediately after irradiation with active energy rays, and is a cured product of an adhesive that cures after a predetermined time,
The adhesive is supplied linearly to at least one of the adhesive surface of the housing and the adhesive surface of the cover panel,
In the cross-section in the direction orthogonal to the longitudinal direction of the adhesive, the dimension of the direction protruding from the adhesive surface of the adhesive is ½ or more of the dimension orthogonal to the direction of protrusion of the portable information terminal Production method. In claim 7,
The method for manufacturing a portable information terminal, wherein a dimension in a direction orthogonal to the protruding direction of the adhesive is 1 mm or less. In claim 7 or 8,
A method for manufacturing a portable information terminal, wherein a frame is formed by the linear adhesive. In any one of Claims 7 thru | or 9,
The adhesive comprises (A) a polyfunctional epoxy compound having two or more epoxy groups in one molecule, and (B) a monofunctional epoxy compound having one epoxy group in one molecule. The manufacturing method of the portable information terminal which is a polymerization composition. In claim 10,
The adhesive further comprises (C) an oxetane compound. In claim 10 or 11,
A method for producing a portable information terminal, wherein at least one of the component (A) and the component (B) has a polyether skeleton in the molecule.