JP5572431B2 - Flat plate laminating resin laminate and laminated flat plate - Google Patents

Description

  The present invention relates to a resin laminate and a laminated flat plate for laminating flat plates, and in particular, a flat plate that can be used as an internal member used for screen display of a portable information terminal device such as a mobile phone or a mobile device. The present invention relates to a laminated resin laminate and a laminated flat plate.

The surface of the information display part of the conventional portable information terminal device has been covered with a bezel cover etc. in order to conceal the electric circuit inside the device. However, in recent years, thin and flat surface designs are preferred. Therefore, in place of the bezel cover, a decorative printing layer is applied in a frame shape to a flat plate serving as a display plate.
Decorative printing is printing that is generally performed to provide concealment and design properties, but the minute steps of about 3 to 50 μm that are provided by performing decorative printing are different from the flat plate of the display board and other It causes air bubbles to be mixed during bonding with the flat plate. For this reason, the problem of bubbles at the time of bonding is often solved by using a film that can bend one of the plates instead of the flat plates.

  On the other hand, many portable information terminal devices equipped with a resistive film type, a capacitive type, an electromagnetic induction type, an infrared type touch panel, etc. are already on the market. (Multi-touch) is possible, which is effective for recent mobile product applications. Since the capacitive touch panel is a system that detects a change in electrostatic capacitance on the surface, a uniform electric field is required. Usually, a film method is effective for reducing the thickness, reducing the weight, and mixing bubbles, but a smooth surface such as glass is effective for forming a uniform electric field. Therefore, the capacitive touch panel requires bonding between flat plates.

  As a method for bonding internal members of a conventional portable information terminal device, Patent Document 1 proposes a double-sided pressure-sensitive adhesive tape using an adhesive on both surfaces of a core material made of a polyurethane film.

  However, in the double-sided pressure-sensitive adhesive tape of Patent Document 1, when a flat plate and a deformable film are bonded, even if there are some steps, it can be applied without leaving bubbles. In the case of bonding between non-deformable surfaces, it is impossible to bond while expelling air bubbles, so it is difficult for air bubbles to enter the bonding surface and to follow the steps completely.

In contrast, Patent Document 2 discloses a pressure-sensitive adhesive layer having a loss tangent of a dynamic viscoelastic spectrum of 0.6 to 1.5 and a storage elastic modulus at 80 ° C. of 1.0 × 10 ⁵ Pa or more. A double-sided PSA sheet has been proposed.

  The double-sided pressure-sensitive adhesive sheet of Patent Document 2 can remove air bubbles mixed when the surface protection panel is attached to the image display panel by autoclaving, and the air bubbles are not restored even if heating is promoted thereafter. No new bubbles are generated.

  Patent Document 3 discloses that a first layer having a tan δ at 25 ° C. of 0.5 or more, a second layer having a tan δ at 25 ° C. of less than 0.5, and a tan δ at 25 ° C. of 0.5 or more. A three-layer impact-resistant film for display has been proposed.

  Also in the impact-resistant film for display of Patent Document 3, bubbles generated at the time of bonding can be removed by heat and pressure treatment, and the bubbles do not recur with time.

Japanese Patent Laid-Open No. 06-346032 JP 2008-231358 A JP 2009-300506 A

  However, when the double-sided pressure-sensitive adhesive sheet of Patent Document 2 and the impact-resistant film for display of Patent Document 3 are attached to a surface having a step instead of a glass panel, bubbles are generated over time after autoclaving. Have been confirmed.

  This invention is made | formed in view of the said situation, Comprising: The bubble produced at the time of bonding of the bonding surfaces of the plane board which has a level | step difference can be removed, and generation | occurrence | production of a bubble over time is suppressed. It aims at providing the resin laminated body for flat plate bonding which can be used, and its laminated flat board.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and found that the problems can be solved by controlling the storage elastic modulus of the resin laminate for laminating flat plates. That is, the present invention provides the following (1) to ( 6 ).
(1) The resin laminate for bonding flat plates of the present invention is a resin laminate for bonding the bonding surfaces of two hard flat plates, and one flat plate is the bonding surface side. Has a step of 3 to 50 μm in height,
It has a resin layer A attached to the bonding surface side of the one flat plate having a step, and a resin layer C applied to the bonding surface side of the other flat plate, and the storage elastic modulus at 23 ° C. towards the resin layer C than the resin layer a is rather high,
The hard flat plate is a glass plate or a plastic plate,
The storage elastic modulus at 23 ° C. of the resin layer A is 0.0001 MPa or more and less than 0.1 MPa, and the storage elastic modulus at 23 ° C. of the resin layer C is 0.1 MPa or more and less than 0.3 MPa. And
(2) The resin laminate for laminating a flat plate of the present invention has a resin layer B between the resin layer A and the resin layer C in the resin laminate, and the storage elastic modulus at 23 ° C. of each resin layer. It is preferable that the relationship is: resin layer A ≦ resin layer B ≦ resin layer C.
(3) In the resin laminate for laminating a flat plate of the present invention, the step is preferably due to the flat plate and a printing layer provided thereon.
( 4 ) The laminated flat plate of the present invention is a laminated flat plate in which two hard flat plates are bonded using the flat plate bonding resin laminate, and one flat plate is the bonding surface. A step having a height of 3 to 50 μm is provided on the side, and the resin layer A is attached to the bonding surface side of the one flat plate having a step, and the resin layer C is bonded to the other flat plate. It is affixed on the surface side.
( 5 ) The laminated flat plate of the present invention is preferably used as a screen display of a portable information terminal device.
( 6 ) The laminated flat plate of the present invention is preferably used as an internal member of a capacitive touch panel.

  According to the resin laminate for laminating a flat plate of the present invention, air bubbles generated at the time of laminating a flat plate having a step can be removed, and the generation of bubbles over time can be suppressed.

  According to the laminated flat plate of the present invention, since it does not have bubbles, it is suitably used as a screen display of a portable information terminal device without impairing the appearance, and the capacitive touch panel without affecting the formation of an electric field. It is suitably used as an internal member.

It is a schematic sectional drawing which shows 1st embodiment of the resin laminated body for flat board bonding of this invention. It is a schematic sectional drawing which shows 1st embodiment of the lamination | stacking plane board of this invention. It is a schematic sectional drawing which shows 2nd embodiment of the resin laminated body for flat board bonding of this invention. It is a schematic sectional drawing which shows 2nd embodiment of the lamination | stacking plane board of this invention.

  The resin laminate for laminating a flat plate of the present invention is a resin laminate for laminating bonding surfaces of two hard flat plates, and one of the flat plates is high on the bonding surface side. A resin layer A that has a step of 3 to 50 μm and is stuck to the bonding surface side of the one flat plate having a step, and a resin layer C that is stuck to the bonding surface side of the other flat plate And the storage elastic modulus at 23 ° C. is higher in the resin layer C than in the resin layer A.

The resin laminate for flat plate bonding of the present invention is not particularly limited as long as it is for bonding the bonding surfaces of two hard flat plates. The flat plate laminating resin laminate comprises at least two layers of a resin layer A and a resin layer C having different storage elastic moduli. The storage elastic modulus at 23 ° C. is higher in the resin layer C than in the resin layer A.
Of the two flat plates used for bonding, one flat plate has a step of 3 to 50 μm in height on the bonding surface side. The other flat plate has substantially no step on the bonding surface side.
By following the step difference, the resin layer A is applied to the bonding surface side of the one flat plate having a step among the both bonding surfaces, and the resin layer C is applied to the bonding surface side of the other flat plate. Property is secured and bubbles do not become a problem.

  The resin laminate for laminating a flat plate of the present invention may have a resin layer B between two layers of a resin layer A and a resin layer C having different storage elastic moduli. The resin laminate for laminating a flat plate of the present invention has a resin layer B between the resin layer A and the resin layer C in the resin laminate, and the relationship of the storage elastic modulus of each resin layer at 23 ° C. It is preferable that the resin layer A ≦ the resin layer B ≦ the resin layer C.

  It is preferable that the relationship of the storage elastic modulus of each resin layer is in an inclined relationship, and when a flat plate bonding resin laminate composed of such resin layers is used for bonding flat plates having steps as described above Generation of bubbles can be suppressed.

Next, an embodiment of the resin laminate for laminating a flat plate and a laminated flat plate of the present invention will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

(1) First embodiment
FIG. 1: is a schematic sectional drawing which shows 1st embodiment of the resin laminated body for flat board bonding of this invention. The flat plate bonding resin laminate 1 of this embodiment is for bonding the two hard flat plates 4 and 6 bonding surfaces 4a and 6a, and has a decorative printing with a thickness of 3 to 50 μm. Resin affixed to the bonding surface 6a side of the other flat plate 6 and the resin layer 2 (resin layer A) affixed to the bonding surface 4a side having the decorative printing layer 5 in the flat plate 4 having the layer 5 It has layer 3 (resin layer C). Further, the storage elastic modulus at 23 ° C. is higher in the resin layer 3 (resin layer C) than in the resin layer 2 (resin layer A).
In FIG. 1, a flat plate having a decorative printing layer 5 as a step is taken as an example. However, the flat plate having a step is not limited to this, for example, a resin-made resin having a three-dimensional design having a step at the time of molding. It may be a flat plate or a flat plate having an electric circuit pattern on the surface.
This flat plate bonding resin laminate 1 is particularly suitable for bonding members used for screen display of portable information terminal devices such as mobile phones and mobile devices.

  The resin laminate 1 for flat plate bonding of this embodiment includes a resin layer 2 (resin layer A) as a constituent element. The material of the resin layer 2 (resin layer A) is not particularly limited, and examples thereof include acrylic resins, rubber resins, silicone resins, and fluorine resins. Among them, an acrylic resin that can easily control the storage elastic modulus and the adhesive force to the flat plate 4 is particularly preferable.

  Although there is no restriction | limiting in particular as an acrylic resin, (meth) acrylic-acid alkylester whose carbon number of an alkyl group is 1-18 is used as an acryl-type monomer which comprises an acryl-type copolymer. Examples of (meth) acrylic acid alkyl esters include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, and methacrylic acid. Examples include n-butyl, isobutyl acrylate, isobutyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, cyclohexyl acrylate, lauryl methacrylate, and dimethylacrylamide.

  Moreover, you may copolymerize the functional group containing monomer copolymerizable with the above-mentioned acrylic monomer. As a copolymerizable functional group-containing monomer, for example, a monomer having a functional group such as hydroxyl group, carboxyl group, amino group, substituted amino group, and epoxy group in the molecule, preferably a hydroxy group-containing unsaturated compound, carboxyl group Containing unsaturated compounds are used. More specific examples of such functional group-containing monomers include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl. Examples thereof include hydroxy group-containing acrylates such as methacrylate, and carboxyl group-containing compounds such as acrylic acid, methacrylic acid, and itaconic acid. The above functional group-containing monomers may be used alone or in combination of two or more.

  Furthermore, a vinyl monomer copolymerizable with the aforementioned acrylic monomer may be copolymerized. Examples of vinyl monomers that can be copolymerized include styrene, α-methylstyrene, vinyl toluene, vinyl formate, vinyl acetate, acrylonitrile, glycidyl acrylate, and glycidyl methacrylate.

  Moreover, you may mix | blend an appropriate additive with an adhesive as needed. Examples of the additive include a crosslinking agent, a tackifier, a pigment, a dye, a filler, and the like, but the above-described polymer alone may be used as the pressure-sensitive adhesive composition without blending them.

  The storage elastic modulus at 23 ° C. of the resin layer 2 (resin layer A) is preferably 0.0001 or more and less than 0.1 MPa, and more preferably 0.001 or more and less than 0.09 MPa. When the storage elastic modulus at 23 ° C. of the resin layer A is 0.0001 MPa or more, there is no fear that the yield decreases due to paste exudation, and the storage elastic modulus at 23 ° C. of the resin layer A is less than 0.1 MPa. Step followability and flat plate bonding suitability are good.

  The thickness of the resin layer A is preferably appropriately selected with respect to the thickness of the step (decorative printing layer 5 described later in the first embodiment), preferably 5 to 200 μm, more preferably 10 to 150 μm, 15-100 micrometers is especially preferable. When the thickness of the resin layer A is 5 μm or more, the step following ability and the flat plate bonding suitability are good, and when the thickness of the resin layer A is 200 μm or less, there is no fear that the yield decreases due to the bleeding of glue. .

  The resin laminate 1 for flat plate bonding of this embodiment includes a resin layer 3 (resin layer C) as a constituent element. The material of the resin layer 3 (resin layer C) is not particularly limited, and as in the case of the resin layer 2 (resin layer A), examples thereof include acrylic resins, rubber resins, silicone resins, fluorine resins, and the like. Particularly preferred is an acrylic resin that allows easy control of the rate and adhesion to the flat plate 6.

  Although there is no restriction | limiting in particular as an acrylic resin, The acrylic resin etc. with which the same acrylic copolymer and additive as what was used by A layer are mentioned.

  The storage elastic modulus at 23 ° C. of the resin layer 3 (resin layer C) is preferably 0.1 or more and less than 0.3 MPa, and more preferably 0.15 or more and less than 0.2 MPa. When the storage elastic modulus at 23 ° C. of the resin layer C is 0.1 MPa or more, there is no fear that the yield decreases due to paste oozing out, and when the storage elastic modulus at 23 ° C. of the resin layer C is less than 0.3 MPa. Step followability and flat plate bonding suitability are good.

  As with the resin layer 2 (resin layer A), the thickness of the resin layer 3 (resin layer C) is preferably 5 to 200 μm, more preferably 10 to 150 μm, and particularly preferably 15 to 100 μm. When the thickness of the resin layer C is 5 μm or more, the step following ability and the suitability for bonding the flat plate are good, and when the thickness of the resin layer C is 200 μm or less, there is no fear that the yield decreases due to the seepage of glue.

As described above, the storage elastic modulus of the resin layer 3 (resin layer C) is higher than the storage elastic modulus of the resin layer 2 (resin layer A). By controlling the resin layer 2 (resin layer A) to the above-mentioned storage elastic modulus, it follows the bonding surface 4a of the flat plate 4 having the decorative printing layer 5 and suppresses the generation of bubbles. Furthermore, by controlling the resin layer 3 (resin layer C) to the storage elastic modulus described above, it is possible to suppress the generation of bubbles due to stress after the bonding surface 6a of the flat plate 6 is bonded.
Moreover, a resin layer can be provided between the resin layer 2 (resin layer A) and the resin layer 3 (resin layer C) as long as the object of the present invention is not impaired.

The thickness of the resin laminate of the present invention is preferably 15 to 600 μm, and more preferably 30 to 250 μm. When the thickness of the resin laminate is 15 μm or more, the step following property and the suitability for laminating the flat plate are good. When the thickness of the resin laminate is 600 μm or less, the workability such as punching decreases, Deterioration of the surface state during film formation can be suppressed.
The thickness of the resin laminate of the present invention is preferably matched to the above-mentioned numerical range, but it is desirable to appropriately select the thickness of the step (decorative printing layer 5 described later in the first embodiment). The thickness of the resin laminate is preferably 5 to 20 times, more preferably 7 to 15 times the thickness of the step. If it is 5 times or more, the step following ability and flat plate bonding suitability are good, and if it is 20 times or less, the deterioration of workability such as punching and the deterioration of the surface condition during the formation of the resin layer are suppressed. it can.

The following method is mentioned as a preparation method of the resin laminated body 1 for flat board bonding.
The above resin solution such as acrylic resin is applied to the heavy release sheet, heated and dried to form the resin layer 2 (resin layer A) on the heavy release sheet, and further the resin layer 2 (resin layer A). The release surface of the light release sheet is laminated to a base material-less adhesive resin sheet sandwiched between two release sheets. Separately, a resin solution is applied to the light release sheet, heated and dried to form the resin layer 3 (resin layer C) on the light release sheet. Further, the resin layer 2 (resin layer A) and the resin layer 3 (resin layer C), which are exposed by peeling off the light release sheet of the above-mentioned substrate-less adhesive resin sheet, are bonded to each other to form a two-layer resin layer. The flat plate bonding resin laminate 1 is obtained.

  Examples of the method for applying the resin solution include conventionally known methods such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, and a curtain coating method.

  According to this flat plate bonding resin laminate 1, the flat plate bonding resin laminate 1 includes a resin layer 2 (resin layer A) and a resin layer 3 (resin layer C) having different storage elastic moduli. Therefore, it is possible to remove bubbles generated when the bonding surface 4a of the flat plate 4 having the decorative printing layer 5 that is a step and the bonding surface 6a of the flat plate 6 are bonded, and generation of bubbles over time. Can be suppressed.

FIG. 2 is a schematic cross-sectional view showing a first embodiment of the laminated flat plate of the present invention. 2, the same components as those used in the description of FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The laminated flat plate 7 of this embodiment is obtained by bonding the bonding surfaces 4a and 6a of the hard flat plates 4 and 6, and the flat plate 4 is decorated and printed as a step on the bonding surface 4a side. Although it has the layer 5, since the resin laminated body 1 which consists of the resin layer 2 (resin layer A) and the resin layer 3 (resin layer C) is used for bonding, a bubble does not arise and visibility is favorable.
The laminated flat plate 7 is particularly suitable for bonding members used for screen display of portable information terminal devices such as mobile phones and mobile devices.

The flat plate 4 constituting the laminated flat plate 7 is not particularly limited as long as it is a hard plate used for a mobile phone or a mobile device, and examples thereof include a glass plate and various plastic plates. Specific examples of the plastic plate include an acrylic plate and a polycarbonate plate.
The flat plate 4 is preferably used as a surface protection panel.

  The thickness of the flat plate 4 is preferably 80 to 5000 μm, more preferably 200 to 4000 μm, and particularly preferably 400 to 3000 μm.

  The said plane board 4 has the decorating printing layer 5 in the bonding surface 4a side. There is no restriction | limiting in particular as a printing method for comprising the decorative printing layer 5, Gravure printing, screen printing, etc. can be used. The printing pattern is not particularly limited, and frame-shaped electrode concealing printing or printing with design properties may be performed.

  The paint for constituting the decorative printing layer 5 is not particularly limited, and a known paint can be used. For example, ultraviolet curable ink, oxidation polymerization type ink, or the like can be used.

  The thickness of the decorative printing layer 5 is 3 to 50 μm, more preferably 4 to 30 μm, and particularly preferably 5 to 20 μm. When the thickness of the decorative printing layer 5 is 3 μm or more, sufficient concealability is obtained, and when it is less than 50 μm, it is not necessary to increase the thickness of the resin laminate of the present invention, and the total thickness does not increase.

The flat plate 6 constituting the laminated flat plate 7 is not particularly limited as long as it is a hard plate used for a mobile phone or a mobile device, and examples thereof include a glass plate and various plastic plates. Specific examples of the plastic plate include an acrylic plate and a polycarbonate plate.
The flat plate 6 may be a laminated plate made of a TCA (triacetyl cellulose) film or the like.

The flat plate 6 is not particularly limited in thickness as long as it is hard and has a flat surface, and is formed by laminating members composed of a plurality of flat plates such as an LCD plate (liquid crystal display plate). Also good. In this case, the flat plate 4 such as an acrylic plate or a glass plate protects the LCD plate from impact.
The flat plate 6 is preferably used as a screen display panel.

  According to this laminated flat plate 7, when applied to a member constituting a screen display of a portable information terminal device such as a mobile phone or a mobile device, no air bubbles are generated after bonding, and thus visibility is improved. Furthermore, when applied to an internal member of a capacitive touch panel, a uniform electric field is formed without affecting the electric field by bubbles.

(2) Second Embodiment FIG. 3 is a schematic cross-sectional view showing a second embodiment of the resin laminate for laminating a flat plate of the present invention. In FIG. 3, the same components as those used in the description of FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.
The flat plate bonding resin laminate 9 is applied to bonding of members used for screen display of portable information terminal devices such as mobile phones and mobile devices, similarly to the flat plate bonding resin laminate 1. Is.

  In addition to the structure of the flat plate bonding resin laminate 1, the flat plate bonding resin laminate 9 of this embodiment is provided between the resin layer 2 (resin layer A) and the resin layer 3 (resin layer C). Furthermore, it has the resin layer 8 (resin layer B). Similar to the flat plate laminating resin laminate 1, the storage elastic modulus at 23 ° C. is higher in the resin layer 3 (resin layer C) than in the resin layer 2 (resin layer A), and the 23 ° C. of each resin layer. The relationship of the storage elastic modulus in is that resin layer 2 (resin layer A) ≦ resin layer 8 (resin layer B) ≦ resin layer 3 (resin layer C).

  The resin laminate 9 for laminating a flat plate of this embodiment includes a resin layer 8 (resin layer B) as a constituent element. The material of the resin layer 8 (resin layer B) is not particularly limited, but, like the resin layer 2 (resin layer A) and the resin layer 3 (resin layer C), an acrylic resin, a rubber resin, a silicone resin, and a fluorine resin Examples thereof include resins and the like, and acrylic resins that can easily control the storage elastic modulus are particularly preferable.

  The thickness of the resin layer 8 (resin layer B) is preferably 5 to 200 μm, more preferably 10 to 150 μm, and particularly preferably 15 to 100 μm, like the resin layer 2 (resin layer A) and the resin layer 3 (resin layer C). preferable. When the thickness of the resin layer C is 5 μm or more, the step following ability and the suitability for bonding to the flat plate are good.

  As for the thickness of the resin laminated body of this invention, 15-600 micrometers is preferable similarly to the resin laminated body 1 for plane board bonding, and 30-250 micrometers is more preferable. When the thickness of the resin laminate is 15 μm or more, the step following property and the suitability for laminating the flat plate are good. When the thickness of the resin laminate is 600 μm or less, the workability such as punching decreases, Deterioration of the surface state during film formation can be suppressed.

The storage elastic modulus at 23 ° C. of the resin layer 8 (resin layer B) is not particularly limited as long as it is 0.0001 to 0.3 MPa, but is not less than the storage elastic modulus of the resin layer 2 (resin layer A). It must be below the storage modulus of (resin layer C).
When the storage elastic modulus at 23 ° C. of the resin layer B is 0.0001 MPa or more, there is no fear that the yield decreases due to the seepage of the paste, and when the storage elastic modulus at 23 ° C. of the resin layer B is 0.3 MPa or less, Good step following ability and flat plate bonding suitability.
Furthermore, since the storage elastic modulus of each resin layer is in the above-described inclination relationship, bubbles generated when used for laminating a flat plate having a step can be removed in the same manner as the flat plate laminating resin laminate 1. And generation | occurrence | production of the bubble with time can be suppressed.

The following method is mentioned as a preparation method of the resin laminated body 9 for flat board bonding.
The resin solution is applied to the heavy release sheet, heated and dried to form the resin layer 2 (resin layer A) on the heavy release sheet, and the release surface of the light release sheet on the resin layer 2 (resin layer A). And a base material-less adhesive resin sheet sandwiched between two release sheets. Separately, a resin solution is applied to the light release sheet, heated and dried, and the resin layer 3 (resin layer C) and the resin layer 8 (resin layer B) are formed on the light release sheet in the same manner as the resin layer A described above. Is formed in the form of a substrate-less adhesive resin sheet. Next, the resin layer 2 (resin layer A) and the resin layer 8 (resin layer B), which are exposed by peeling off the light release sheet of the base material-less adhesive resin sheet of the resin layer A, are bonded together, and the two-layer resin A layered resin laminate for laminating a flat plate is obtained. Furthermore, the resin layer 8 (resin layer B) and the resin layer 3 (resin layer C) which peeled and exposed the light release sheet | seat of the resin laminated body for flat board bonding which consists of the said two resin layers were bonded, A flat laminate laminating resin laminate composed of three resin layers is obtained.

  According to this flat plate bonding resin laminate 9, in addition to the flat plate bonding resin laminate 1, a resin layer is further provided between the resin layer 2 (resin layer A) and the resin layer 3 (resin layer C). By laminating 8 (resin layer B), in addition to the effect of the resin laminate 1 for laminating a flat plate, it has excellent impact resistance. The impact resistance is obtained by absorbing the stress applied to the plane 4 by the flat plate laminating resin laminate 9 bonded to the entire surface.

FIG. 4 is a schematic cross-sectional view showing a second embodiment of the laminated flat plate of the present invention. In FIG. 4, the same components as those used in the description of FIGS.
The laminated flat plate 10 of this embodiment is obtained by bonding the bonding surfaces 4a and 6a of the hard flat plates 4 and 6, and the flat plate 4 is a decoration that is a step on the bonding surface 4a side. Although it has the printing layer 5, since the resin laminated body 10 which consists of the resin layer 2 (resin layer A), the resin layer 8 (resin layer B), and the resin layer 3 (resin layer C) is used for bonding, a bubble does not arise Visibility is good.
The laminated flat plate 10 is particularly suitable for bonding members used for screen display of portable information terminal devices such as mobile phones and mobile devices.

  According to the laminated flat plate 10, in addition to the effect of the laminated flat plate 7, when applied to a screen display of a portable information terminal device such as a mobile phone or a mobile device, the screen display is broken when subjected to an impact. The shock absorbing property is obtained by absorbing the stress applied to the flat surface 4 at the time of impact and preventing the stress applied to the flat plate bonding resin laminate 9 on the entire surface from being absorbed.

As described above, as described in the above embodiment, the laminated flat plate of the present invention is preferably used as a screen display member of a portable information terminal device.
In recent years, a screen display unit of a portable information terminal device has a framed decorative printing layer on a flat plate serving as a display plate from the viewpoint of reducing the thickness and blocking excess light from the end surface of the information display unit. The minute steps provided by performing the decorative printing cause air bubbles to be mixed when the flat plate of the display plate is bonded to another flat plate. Such bubbles are detrimental to aesthetics.
Since the laminated flat plate of the present invention uses the resin laminated body for bonding a flat plate of the present invention, which has excellent step following ability, there is no possibility that bubbles are generated inside. Therefore, the said malfunction can be eliminated by using the said laminated plane board for the screen display of a portable information terminal device.

The laminated flat plate of the present invention is more preferably used as an internal member of a capacitive touch panel.
Many portable information terminal devices equipped with a touch panel such as a resistive film type, a capacitance type, an electromagnetic induction type, and an infrared type have already been put on the market. Since this is a method for detecting changes, a uniform electric field is required. In order to form a uniform electric field, a smooth surface such as glass is effective. Therefore, the capacitive touch panel requires bonding between flat plates.
The resin laminate for laminating flat plates of the present invention is excellent in step pasting suitability even when laminating hard flat plates. Therefore, the laminated flat plate of the present invention using the flat plate laminating resin laminate can maintain a uniform electric field without affecting the electric field by bubbles.
Therefore, the said laminated plane board can be used suitably for the internal member of a capacitive touch panel.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

(Preparation of resin solution 1)
100 parts by mass of acrylic copolymer (BA / MA / 4HBA = 79/20/1, weight average molecular weight 900,000) composed of butyl acrylate (BA), methyl acrylate (MA), 4-hydroxybutyl acrylate (4HBA) , An isocyanate-based crosslinking agent (manufactured by Soken Chemical Co., Ltd., product name “TD-75”, concentration 75%) was mixed with 0.05 part by mass and diluted with methyl ethyl ketone to prepare a resin solution 1 having a nonvolatile content concentration of 30%. .

(Preparation of resin solution 2)
100 parts by mass of an acrylic copolymer (BA / EA / AAc = 77: 20: 3, weight average molecular weight 900,000) composed of butyl acrylate (BA), ethyl acrylate (EA), and acrylic acid (AAc) 4 parts by mass of a system cross-linking agent (manufactured by Soken Chemical Co., Ltd., product name “M-5A”, concentration 4.95%) was mixed and diluted with methyl ethyl ketone to prepare a resin solution 2 having a nonvolatile content concentration of 30%.

(Preparation of resin solution 3)
100 parts by mass of an acrylic copolymer (BA / MA / AAc = 77: 20: 3, weight average molecular weight 900,000) composed of butyl acrylate (BA), methyl acrylate (MA), and acrylic acid (AAc) 1.75 parts by mass of a cross-linking agent (manufactured by Toyo Ink, product name “BHS-8515”, concentration 37.5%) and an aluminum chelate cross-linking agent (manufactured by Soken Chemicals, product name “M-5A”, concentration 4) .95%) 1.75 parts by mass were mixed and diluted with methyl ethyl ketone to prepare Resin Solution 3 having a nonvolatile content concentration of 28%.

(Preparation of resin solution 4)
Methyl ethyl ketone diluted solution of an acrylic pressure-sensitive adhesive (product name “PM”, manufactured by Lintec Corporation) was used as the resin solution 4.

(Preparation of resin solution 5)
Acrylic copolymer composed of 2-ethylhexyl acrylate (2EHA), cyclohexyl acrylate (CHA), 2-hydroxyethyl acrylate (HEA) (2EHA / CHA / HEA = 59.7: 40: 0.3, weight average molecular weight 80 10) 100 parts by mass of an isocyanate-based crosslinking agent (product name “BHS-8515”, manufactured by Toyo Ink Co., Ltd., concentration: 37.5%) mixed with 0.5 parts by mass, diluted with methyl ethyl ketone, and having a nonvolatile content of 30%. Resin solution 5 was prepared.

Example 1
The resin solution 1 was applied to a heavy release sheet (product name “SP-PET3811” manufactured by Lintec Corporation) and heated at 120 ° C. for 2 minutes to form an A layer having a thickness of 100 μm on the heavy release sheet. Furthermore, a release surface of a light release sheet (product name “SP-PET3801”, manufactured by Lintec Corporation) was laminated on the A layer to prepare a base-less adhesive resin sheet sandwiched between two release sheets. Separately, the resin solution 2 was applied to a light release sheet (product name “SP-PET3801” manufactured by Lintec Corporation) and heated at 120 ° C. for 2 minutes to form a C layer having a thickness of 50 μm on the light release sheet. . Furthermore, the A-layer and C-layer which peeled off and exposed the light release sheet of the above-mentioned base-less-adhesive resin sheet were bonded, and the resin laminated body for flat board bonding of Example 1 which consists of two resin layers Got.

(Example 2)
Resin laminate for laminating a flat plate of Example 2 in the same manner as in Example 1 except that the A layer is made of a resin solution 1 having a thickness of 100 μm and the C layer is made of a resin solution 3 having a thickness of 50 μm. Got.

(Example 3)
The resin solution 4 was applied to a heavy release sheet (product name “SP-PET3811” manufactured by Lintec Corporation) and heated at 120 ° C. for 2 minutes to form an A layer having a thickness of 50 μm on the heavy release sheet. Furthermore, a release surface of a light release sheet (product name “SP-PET3801”, manufactured by Lintec Corporation) was laminated on the A layer to prepare a base-less adhesive resin sheet sandwiched between two release sheets.
Separately, the resin solution 1 was applied to a light release sheet (product name “SP-PET3801” manufactured by Lintec Corporation) and heated at 120 ° C. for 2 minutes to form a B layer having a thickness of 50 μm on the light release sheet. . Next, A layer and B layer which peeled and exposed the light release sheet of the above-mentioned substrateless adhesive resin sheet were pasted together, and the resin laminated body for plane board pasting which consists of two resin layers was obtained. .
Separately, the resin solution 2 was applied to a light release sheet (product name “SP-PET3801” manufactured by Lintec Corporation) and heated at 120 ° C. for 2 minutes to form a C layer having a thickness of 50 μm on the light release sheet. . Subsequently, the B layer and the C layer, which are exposed by peeling off the light release sheet of the resin laminate for laminating a flat plate composed of the two resin layers described above, are bonded to each other, and Example 3 consisting of three resin layers A flat plate bonding resin laminate was obtained.

(Example 4)
Resin laminate for laminating a flat plate of Example 4 in the same manner as in Example 1 except that the A layer is composed of the resin solution 1 having a thickness of 100 μm and the C layer is composed of the resin solution 5 having a thickness of 50 μm. Got.

(Comparative Example 1)
The same method as in Example 3 except that the A layer is composed of the resin solution 1 having a thickness of 50 μm, the B layer is composed of the resin solution 2 having a thickness of 50 μm, and the C layer is composed of the resin solution 1 having a thickness of 50 μm. Thus, a resin laminate for flat plate bonding of Comparative Example 1 was obtained.

(Comparative Example 2)
Resin laminate for laminating a flat plate of Comparative Example 2 in the same manner as in Example 1 except that the A layer is composed of the resin solution 2 having a thickness of 50 μm and the C layer is composed of the resin solution 1 having a thickness of 50 μm. Got.

(Comparative Example 3)
The same method as in Example 3 except that the A layer is composed of the resin solution 2 having a thickness of 50 μm, the B layer is composed of the resin solution 2 having a thickness of 50 μm, and the C layer is composed of the resin solution 2 having a thickness of 50 μm. Then, a flat plate bonding resin laminate of Comparative Example 3 was obtained. The resin laminate for flat plate bonding of Comparative Example 3 is made of substantially the same resin 2 in all three layers.

(Comparative Example 4)
The same method as in Comparative Example 3 except that the A layer is composed of the resin solution 4 having a thickness of 50 μm, the B layer is composed of the resin solution 4 having a thickness of 50 μm, and the C layer is composed of the resin solution 4 having a thickness of 50 μm. Thus, a flat plate bonding resin laminate of Comparative Example 4 was obtained. The flat plate bonding resin laminate of Comparative Example 4 is made of substantially the same resin 4 in all three layers.

The properties of the resin laminates for laminating flat plates of each Example and each Comparative Example were measured by the following test methods, and the results are shown in Table 1.
(1) Thickness measurement The release sheet of the base-less adhesive resin sheet obtained in Examples and Comparative Examples was removed, and a constant pressure thickness measuring instrument (product name: PG-02, manufactured by Teclock Co., Ltd.) according to JIS K7130. ). The thickness of each resin layer was measured in the state of a single resin layer before lamination.

(2) Storage elastic modulus The release sheet of the base-less adhesive resin sheet obtained in Examples and Comparative Examples was removed, and a plurality of sheets were overlapped to form a sheet sample having a thickness of 2.0 mm. The formed sheet sample is cut into a cylindrical shape with a diameter of 8.0 mm and a height of 2.0 mm, and twisted using a viscoelasticity measuring device (Rheometric Scientific F.E., trade name “RDAII”). The storage elastic modulus at 23 ° C. was measured at a measurement frequency of 1 Hz by the shear method.

(3) Applicability to level difference application (whether foaming is present)
On the surface of an acrylic resin plate (Mitsubishi Rayon Co., Ltd., product name “Acrylite L011”, length 70 mm × width 40 mm × thickness 1.5 mm), UV curable ink (product name “POS-911 Black”, manufactured by Teikoku Inc.) ) Printing was performed in a frame shape (outer shape, length 70 mm × width 40 mm, width 5 mm) so that the coating thickness was 10 μm and 20 μm, and UV curing was performed to produce an acrylic plate having a step due to printing.
The substrate-less adhesive resin sheets obtained in Examples and Comparative Examples were cut into a shape of 70 mm in length and 40 mm in width, the light release sheet was removed, and a laminator (manufactured by Fuji Pla Co., Ltd.) was applied to the exposed resin layer surface. Using a product name “LPD3214”), the printed surface of the acrylic plate was laminated so as to cover the entire frame-like printed surface.
After lamination, the heavy release sheet was peeled off, and a glass plate (product name “Corning Glass Eagle XG”, thickness 1.5 mm × length 70 mm × width 70 mm) manufactured by NSG Precision Co., Ltd. was laminated on the exposed resin layer surface with the laminator. A sample for evaluating applicability of steps was prepared.
Then, the autoclave process (50 degreeC, 0.5 Mpa, 20 minutes) was performed, and the presence or absence of the bubble was confirmed. The presence or absence of bubbles was determined in three stages according to the following criteria.
○: No bubbles at all △: Bubbles are mixed in one or two places ×: Bubbles are mixed in three or more places Also, leave at 23 ° C and 50% Rh for 7 days. confirmed.

(4) Punching process The substrate-less adhesive resin sheets obtained in the examples and comparative examples are punched into a size of 70 mm in length and 40 mm in width with a punching device (product name: LPM300, manufactured by Lintec Corporation). The deformation of the resin laminate and the seepage of the resin layer were confirmed. When there was shape deformation or resin layer leaching, it was judged as x, and when there was no shape deformation or resin layer leaching, it was judged as ◯.
Table 1 summarizes the results of the tests in each Example and Comparative Example.

  As shown in Table 1, the resin laminate for laminating a flat plate of the present invention obtained in the Examples showed good step pasting suitability for acrylic plates having printing steps of 10 μm and 20 μm. On the other hand, in the resin laminate for laminating a flat plate obtained in Comparative Example 1 in which the storage elastic modulus between the layers is not inclined and Comparative Example 2 in which the storage elastic modulus of the A layer is 0.1 MP or more, step bonding The aptitude was poor. Furthermore, in the resin laminated body for flat plate bonding obtained in Comparative Example 3 and Comparative Example 4 consisting of only one layer, the step sticking suitability or punching processability was inferior.

1 and 9 Resin laminate 2 for laminating flat plates Resin layer A
3 Resin layer C
8 Resin layer B
4, 6 Planar plates 4a, 6a Laminating surface 5 Decorative printing layer 7, 10 Laminated plane plate

Claims (6)

It is a resin laminate for bonding the bonding surfaces of two hard flat plates, and one flat plate has a step of 3 to 50 μm in height on the bonding surface side.
It has a resin layer A attached to the bonding surface side of the one flat plate having a step, and a resin layer C applied to the bonding surface side of the other flat plate, and the storage elastic modulus at 23 ° C. towards the resin layer C than the resin layer a is rather high,
The hard flat plate is a glass plate or a plastic plate,
The storage elastic modulus at 23 ° C. of the resin layer A is 0.0001 MPa or more and less than 0.1 MPa, and the storage elastic modulus at 23 ° C. of the resin layer C is 0.1 MPa or more and less than 0.3 MPa. A resin laminate for laminating flat plates.   In the resin laminate, the resin layer B is further provided between the resin layer A and the resin layer C, and the relationship of the storage elastic modulus at 23 ° C. of each resin layer is as follows: resin layer A ≦ resin layer B ≦ resin layer C The resin laminate for flat plate bonding according to claim 1. The resin laminate for bonding a flat plate according to claim 1 or 2 , wherein the step is a step formed by a flat plate and a printing layer provided thereon. A laminated flat plate in which two hard flat plates are bonded using the flat plate bonding resin laminate according to any one of claims 1 to 3 ,
One flat plate has a step of 3 to 50 μm in height on the bonding surface side, the resin layer A is bonded to the bonding surface side of the one flat plate having a step, and the resin layer C is A laminated flat plate, which is attached to the bonding surface side of the other flat plate. The laminated flat plate according to claim 4, which is used as a screen display member of a portable information terminal device. The laminated flat plate according to claim 5, which is used as an internal member of a capacitive touch panel.

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