JP2007073824A - Adhesive layer for emi film lamination and emi laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive layer for EMI film lamination which can be peeled off without producing a defect on a mesh surface, is excellent in transferability of an adhesive layer, and can be stably held for long time. <P>SOLUTION: The adhesive layer for EMI film lamination contains an acrylic polymer A whose composition unit having a functional group is 0.1-10 pts.wt., the molecular weight of mean weight is 500,000 or more, and the glass transition temperature Tg is -20°C or lower; an acrylic oligomer B whose composition unit having a functional unit capable of reacting with a hardening agent C is contained in 0.1-25 pts.wt., and the molecular weight of mean weight is 50,000 or less; and a hardening agent C whose shortest functional group molecular weight shown in molecular weight/the number of functional groups is 600 or more. The amount of variation measured for the adhesive layer in a fine compression test is 15 μm/mN or more, and the adhesive layer is blended with the composition A, the composition B, and the hardening agent C so that a ratio of a holding force in the tape at 80°C/a holding force in the tape at 40°C is 0.01 or less, and the EMI lamination film has the adhesive layer on a supporter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an adhesive layer disposed for laminating an EMI shield film that is attached to the surface of a display device or the like and shields electromagnetic waves, and an EMI laminate film having such an adhesive layer.

  An electromagnetic wave shielding thin film is disposed on the front surface of the display device or the like so as to block electromagnetic waves generated from the display device. The electromagnetic shielding thin film disposed on the front surface of such a display device does not block visible light from the display device portion on the back side of the electromagnetic shielding thin film, and blocks electromagnetic waves as much as possible. There is a need.

  That is, for example, in an apparatus using a high frequency such as a microwave oven, the electromagnetic wave shielding member does not require high transparency, but in the electromagnetic wave shielding member for a display device, visible light is not blocked and other electromagnetic waves are not blocked. Therefore, an electromagnetic wave shielding member that shields with high selectivity is required.

  Various studies have been made as an electromagnetic wave shielding member for such a display device. A metal foil such as a copper foil, which is a conductive metal, is attached to the surface of a support, and a photoresist layer is formed on the surface of the metal foil. Then, by exposing and developing a predetermined mesh pattern on the photoresist, a mesh pattern made of a cured photoresist is formed, and using this mesh pattern as a masking material, the conductive metal foil is etched to obtain a line width of 5 μm. A grid-like metal pattern having a mesh opening of about 400 μm is formed, and a pressure-sensitive adhesive layer and a highly transparent pressure-sensitive adhesive layer such as PET are formed on the surface of the mesh-shaped metal pattern thus formed. Place it so that it faces the mesh metal pattern, so that the mesh metal pattern is buried in the adhesive layer. An electromagnetic wave shielding member manufactured by bonding a transparent resin film with an adhesive layer and a display device is known.

The electromagnetic wave shielding member having such a configuration has, for example, a cross-sectional structure as shown in FIG. 1 (e). In FIG. 1 (e), the middle layer is an EMI film, and the EMI film A Cu mesh made of copper is formed on the surface of the substrate, and the Cu mesh is covered with an adhesive layer 25 μm and PET 50 μm so as to cover the Cu mesh.

Therefore, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer in the electromagnetic wave shielding member must have fluidity to follow the shape of the surface of the Cu mesh formed in a lattice shape, and the Cu mesh on the surface of the EMI film further Since it is necessary to be completely covered with the adhesive layer 25 μm, high adhesiveness is required.

Therefore, it is preferable that the Cu mesh pattern contained by the EMI film and the adhesive layer in this electromagnetic wave shielding member is stably contained for a longer period of time in a state of being isolated from the outside, so that the adhesive layer is formed. As the pressure-sensitive adhesive, a pressure-sensitive adhesive having extremely high adhesive strength is used so that peeling does not occur at this pressure-sensitive adhesive interface.

By the way, as various types of display devices such as liquid crystal displays and PDP displays are actually used, when the adhesive layer is attached to the EMI film, there are defects in the attachment. There is a problem that the film having the pressure-sensitive adhesive layer cannot be peeled off. In other words, a substrate having a Cu mesh is formed through a plurality of processes as described above, and on the other hand, a laminate comprising a PET 50 μm thickness / adhesive layer has a two-layer structure and is relatively easy. Can be manufactured. When there is a sticking failure, the entire EMI film is discarded. However, Cu mesh patterns are expensive, and it is extremely disadvantageous in terms of cost to discard a large number of substrates on which expensive Cu mesh patterns are formed.

  Therefore, if a sticking failure occurs, if the expensive EMI film side can be saved, even if the low-priced laminate of PET 50 μm / adhesive layer 25 μm is abandoned, it can be fully profitable. However, the conventional adhesive layer with a thickness of 25 μm mainly consists of embedding Cu mesh stably, so when the Cu mesh comes in contact with the adhesive layer 25 μm, the adhesive strength of this adhesive layer 25 μm is high. When peeling is used, the Cu mesh is transferred to the adhesive layer 25 μm side and peeled off from the EMI film. That is, in the EMI film used for the display device, a pressure-sensitive adhesive having a high adhesive strength is used in order to reliably cover the Cu mesh for a long period of time.

For example, Patent Document 1 (Japanese Patent Laid-Open No. 2000-294981) discloses a film obtained by coating an electromagnetic wave shielding film with an adhesive having a specific storage elastic modulus. Further, the adhesive used in Patent Document 1 is It is disclosed that it is a blend of two types of acrylic polymers having different molecular weights. In Patent Document 1, the heat-resistant cohesive force is such that the storage elastic modulus at a low temperature (25 ° C.) is 5 × 10 ⁵ Pa or more and the storage elastic modulus at a high temperature (80 ° C.) is 5 × 10 ⁴ Pa or less. A pressure-sensitive adhesive composition that decreases with temperature is used, and a pressure-sensitive adhesive composition having such a high temperature dependency tends to cause poor adhesion due to peeling or foaming when the temperature becomes higher than expected.

Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-107507) discloses a film with an adhesive for electronic display in which an adhesive layer is formed on one surface of a light-transmitting film. It is disclosed that the layer is composed of a (meth) acrylic resin having a weight average molecular weight of 200,000 or more and a (meth) acrylic resin having a weight average molecular weight of less than 200,000.

As described above, Patent Document 1 and Patent Document 2 indicate that a blend of different acrylic polymers is used as an adhesive.
Such an adhesive has a very high adhesive strength, and has very excellent characteristics for forming a layer covering a Cu mesh pattern. However, such conventional EMI
It is not assumed that the film peels off the pressure-sensitive adhesive layer that covers the Cu mesh pattern and then sticks it again.
Japanese Unexamined Patent Publication No. 2000-294981 JP 2002-107507 A

  The present invention provides a pressure-sensitive adhesive layer for EMI film lamination that can reliably cover a mesh pattern and can be stably maintained for a long period of time, and that does not damage the mesh pattern even by peeling, and an EMI having this pressure-sensitive adhesive layer The object is to provide a laminate film.

The adhesive layer for EMI film lamination of the present invention is
A repeating unit having a functional group is added in an amount of 0.1 to 10 in 100 parts by weight of the acrylic polymer (A).
An acrylic polymer (A) containing in an amount of parts by weight, having a weight average molecular weight of 500,000 or more and a glass transition temperature (Tg) of −20 ° C. or less;
Acrylic oligomer having a repeating unit having a functional group capable of reacting with the curing agent (C) in an amount of 0.1 to 25 parts by weight and a weight average molecular weight of 50,000 or less in 100 parts by weight of the acrylic oligomer (B). Oligomer (B),
and,
Containing a curing agent (C) having a shortest functional group molecular weight of 600 or more represented by molecular weight / number of functional groups,
The displacement amount of the micro compression test measured for the pressure-sensitive adhesive layer obtained from the components (A), (B) and (C) is 15 μm / mN or more,
Ratio of holding power value at 80 ° C. per unit width of the tape having the pressure-sensitive adhesive as a pressure-sensitive adhesive layer and holding power value at 40 ° C. per unit width of the tape (80 ° C. holding power value−40 ° C. holding power value) ) Is 0.01 or less, the acrylic polymer (A), the acrylic oligomer (B) and the curing agent (C) are blended.

The EMI laminate film of the present invention is
On the support film surface,
A repeating unit having a functional group is added in an amount of 0.1 to 10 in 100 parts by weight of the acrylic polymer (A).
An acrylic polymer (A) containing in an amount of parts by weight, having a weight average molecular weight of 500,000 or more and a glass transition temperature (Tg) of −20 ° C. or less;
An acrylic having a repeating unit having a functional group capable of reacting with the curing agent (C) in an amount of 0.1 to 25 parts by weight and having a weight average molecular weight of 50,000 or less in 100 parts by weight of the acrylic oligomer (B). Oligomer (B),
and,
Containing a curing agent (C) having a shortest functional group molecular weight of 600 or more represented by molecular weight / number of functional groups,
The displacement amount of the micro compression test measured for the pressure-sensitive adhesive layer obtained from the components (A), (B) and (C) is 15 μm / mN or more,
Ratio of holding power value at 80 ° C. per unit width of the tape having the pressure-sensitive adhesive as a pressure-sensitive adhesive layer and holding power value at 40 ° C. per unit width of the tape (80 ° C. holding power value−40 ° C. holding power value) ) That the pressure-sensitive adhesive layer for the EMI film laminate is formed by blending the acrylic polymer (A), the acrylic oligomer (B), and the curing agent (C) so that it is 0.01 or less. It is a feature.

  Since the EMI laminate film is stuck on a very fine mesh pattern formed by etching a copper foil, it needs to have a high holding power, and a large number of copper mesh patterns are formed. Since it is made to stick to the surface with an unevenness | corrugation, a good fluidity is needed.

  In general, it is considered that the holding power in bonding is determined by the number of crosslinking points and the number of branches at the crosslinking points. That is, as the number of cross-linking points increases and the number of cross-linking points increases, the holding power increases.

  When the crosslink density is increased and the holding power is increased, the fluidity of the pressure-sensitive adhesive layer for allowing the pressure-sensitive adhesive layer to flow in the Cu mesh pattern is insufficient, and the optical properties decrease the total light transmittance and increase the haze. Moreover, since the cohesive force (= holding force) is too high in mounting, peeling occurs.

  In order to prevent such a phenomenon, if the crosslink density is lowered, the optical characteristics increase the total light transmittance, haze decreases, the optical characteristics generally improve, but the cohesive force decreases in mounting, It becomes easy to foam.

In this way, in order to achieve both optical characteristics and mounting characteristics in the EMI film laminating adhesive layer or EMI film laminating adhesive layer, the adhesive layer can be flowed by autoclaving (heating and pressurizing) during sample preparation. It is necessary to reduce the temperature dependence of the holding force.

For this purpose, it is very important that the structure formed by the cross-linking agent is a structure with a high degree of freedom and a structure capable of maintaining a high holding force.
In order to form the structure as described above, the inventor of the present application increases the molecular weight of the structure between the functional group molecules of the crosslinking agent to a value greater than a specific value, and further crosslinks and oligomers that can react with the crosslinking agent. It has been found that the degree of freedom of the cross-linking points can be increased by reacting at least a part with the cross-linking agent and allowing the oligomer of the cross-linking agent to participate in the formation of the cross-linked structure.

  Since the number of crosslinking points is adjusted by this combination, the pressure-sensitive adhesive layer of the present invention has a high holding force, but the temperature dependency of the holding force is lowered, and the problem in the mounting test is solved. In addition, since the degree of freedom of the structure formed including the cross-linking point is high, good fluidity is imparted to the pressure-sensitive adhesive layer by the autoclave treatment, and the pressure-sensitive adhesive layer has very high transfer characteristics, The Cu mesh pattern shape can be transferred to the adhesive layer with very high accuracy. For this reason, by sticking the adhesive layer of the present invention, good optical properties are exhibited, and the shape of the mesh pattern is transferred very well, so that problems during mounting are less likely to occur. .

  In the present invention, the micro-compression test is a test for measuring displacement due to application of high pressure, and when the degree of crosslinking is increased in a state where there is no degree of freedom of crosslinking points, the amount of displacement is small and the configuration of the present invention is adopted. When a cross-linked structure is formed, the amount of change increases.

  When a bifunctional type curing agent having a large distance between functional groups is used, a structure that is relatively similar to that of the present invention tends to be formed. When one of the functional groups of the curing agent is not reacted, the holding force cannot be increased, and the preparation thereof is very difficult.

The present invention provides an EMI film laminate pressure-sensitive adhesive layer and an EMI laminate film having a new structure.
The pressure-sensitive adhesive layer for EMI film laminating and the EMI laminated film of the present invention use a curing agent having a specific shortest functional group molecular weight in the pressure-sensitive adhesive layer, and the displacement range in the micro compression test is within a specific range. By determining the composition so as to become, it is possible to enhance the fluidity during lamination and to improve the transferability to the mesh surface-shaped adhesive layer after lamination.

  Further, the adhesive layer for EMI film lamination and the EMI laminate film of the present invention peel off the EMI film attached to the mesh surface when a sticking defect to the EMI film is found after lamination as described above. Can do. That is, even after the pressure-sensitive adhesive layer for EMI film lamination and the pressure-sensitive adhesive layer for EMI film lamination of the present invention are attached to the mesh pattern forming surface formed of a conductive metal such as copper, This pressure-sensitive adhesive layer can be peeled off with little damage to the formed mesh surface. Moreover, despite the fact that the pressure-sensitive adhesive layer for EMI film lamination and the EMI laminated film of the present invention have reworkability, the transferability of the pressure-sensitive adhesive layer is very good, and the holding power is within a specific range. By adjusting, the movement of the pressure-sensitive adhesive layer is small even under mounting conditions, the transfer state at the time of sticking is stably maintained for a long time, and problems such as foaming do not occur.

Hereinafter, the adhesive layer for EMI film lamination and the EMI laminate film of the present invention will be described in detail.
The acrylic polymer (A) that can be used in the present invention is composed of an acrylic polymer having a weight average molecular weight of 500,000 or more, preferably 500,000 to 2,000,000 mainly composed of alkyl (meth) acrylate, and a glass transition temperature. (Tg) is an acrylic polymer having a temperature of −20 ° C. or lower, preferably −30 ° C. or lower. By limiting the glass transition temperature (Tg) of the acrylic polymer (A) as described above, the EMI laminate film of the present invention has good adhesive strength. In the present invention, the weight average molecular weight (Mw) of the polymer is a value measured by gel permeation chromatography (GPC).

Moreover, the acrylic polymer (A) used here has a functional group, and in order to form such a functional group, the monomer having the functional group is within a range of 0.1 to 10% by weight. Used in an amount, preferably in the range of 0.5 to 6.0% by weight.

When the weight average molecular weight of the acrylic polymer (A) used in the pressure-sensitive adhesive layer for EMI film lamination and the EMI laminate film of the present invention is less than 500,000, the EMI laminate film formed by sticking may foam. is there.

Examples of alkyl (meth) acrylates that form this acrylic polymer (A) include methyl (meth) acrylate (MA for methyl acrylate, MMA for methyl methacrylate); ethyl (meth) acrylate (for ethyl acrylate) , EA), n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, n-butyl (meth) acrylate, pentyl (meth) acrylate, (Meth) acrylates having an alkyl group having 2 to 16 carbon atoms, preferably 4 to 8 carbon atoms such as hexyl (meth) acrylate and octyl (meth) acrylate; cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl Mention of (meth) acrylate and ethyl carbitol (meth) acrylate Can. This alkyl group may be a straight chain or a branched alkyl group. In the present invention, the above alkyl (meth) acrylates can be used alone or in combination.

The acrylic polymer (A) used in the present invention is preferably a copolymer of the above alkyl acrylate and a monomer having a functional group.
Examples of functional group-containing monomers used in the present invention include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and cyclohexanedimethanol mono (meth) acrylate. Hydroxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid and other carboxyl group-containing monomers; N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate Examples include amino group-containing (meth) acrylic monomers such as; amide group-containing acrylic monomers such as (meth) acrylamide and N-methylacrylamide. In the present invention, the above functional group-containing polymers can be used alone or in combination.

In the present invention, it is preferable to use a hydroxyl group-containing monomer as the functional group-containing monomer. Further, as the hydroxyl group-containing monomer, 2-hydroxyethyl acrylate (2-HEA)
, 2-hydroxypropyl acrylate (2-HPA), 4-hydroxybutyl acrylate (4-HBA) cyclohexane dimethanol monoacrylate (CHDMAA), monoesters and lactones of (meth) acrylic acid with polypropylene glycol or polyethylene glycol And a hydroxyl group-containing vinyl compound such as an adduct of 2-hydroxyethyl (meth) acrylate. Among these, 2-hydroxyethyl acrylate (2-HEA), cyclohexane dimethanol monoacrylate (CHDMAA), and 4-hydroxybutyl acrylate (4-HBA) are preferably used in the present invention.

  The acrylic polymer (A) used in the present invention can be copolymerized with other monomers having reactivity to alkyl (meth) acrylate in addition to the functional group as described above. .

The amount of the functional group-containing monomer in 100 parts by weight of the acrylic polymer is in the range of 0.1 to 10 parts by weight, preferably 1 to 4 parts by weight.
The acrylic polymer (A) used in the present invention can be produced by polymerizing the components as described above. The acrylic polymer (A) can be produced by a method such as bulk polymerization, emulsion polymerization, or solution polymerization. In the present invention, the acrylic polymer (A) is preferably produced by solution polymerization.

  Examples of the solvent that can be used here include organic solvents such as methanol, ethanol, methyl ethyl ketone, ethyl acetate, butyl acetate, toluene, xylene, and hexane.

  In the present invention, the above organic solvents can be used alone or in combination. In particular, in the present invention, the polymerization temperature can be adjusted by using a plurality of organic solvents. For example, by using 20 parts by weight of toluene and 130 parts by weight of ethyl acetate, the polymerization reaction can be carried out at 50 ° C. to 80 ° C., specifically around 70 ° C., and 60 parts by weight of toluene and 90 parts by weight of ethyl acetate. The polymerization reaction can be carried out at around 50 ° C to 90 ° C.

In producing the acrylic polymer (A), a polymerization initiator is usually used.
The acrylic polymer (A) used in the present invention can be produced by polymerizing the monomer in the presence of a polymerization initiator.

  Examples of the polymerization initiator that can be used here include organic solvent-soluble polymerization initiators such as azoisobutyronitrile (AIBN). The amount of the polymerization initiator used is usually 0.01 to 1.0 part by weight, preferably 0.05 to 0, based on 100 parts by weight of the monomer forming the acrylic polymer (A). .5 parts by weight. This polymerization initiator can be divided and added to the reaction system.

  The acrylic polymer thus formed can be obtained as a solution dissolved in an organic solvent or a dispersed dispersion. The solid content in the organic solvent solution or dispersion is usually 10 to 50% by weight, preferably 20 to 30% by weight.

Acrylic oligomer (B) blended in the adhesive layer for EMI film lamination in the present invention
In 100 parts by weight, a repeating unit having a functional group capable of reacting with the curing agent (C) described later is added in an amount of 0.00.
An acrylic oligomer (B) having an amount of 1 to 25 parts by weight, preferably 2 to 10 parts by weight, and having a weight average molecular weight of 50,000 or less.

The alkyl (meth) acrylate forming the acrylic oligomer (B) has an alkyl group having 2 to 16 carbon atoms, preferably 2 to 8 carbon atoms, as in the case of forming the acrylic polymer (A). Mention may be made of (meth) acrylates. This alkyl group may be a straight chain or a branched alkyl group. In the present invention, the above alkyl (meth) acrylates can be used alone or in combination.

Also used in combination with the above alkyl (meth) acrylate, acrylic oligomer (B
The functional group-containing monomer is not particularly limited as long as the functional group reacts with the curing agent (C) described later. Among these functional group-containing monomers, the acrylic polymer (A) It is desirable to use a functional group-containing monomer having the same type of functional group as that of the functional group-containing monomer that forms the.

For example, when the acrylic polymer (A) contains, for example, a hydroxyl group as a functional group, an acrylic oligomer (B) having a hydroxyl group is preferably used.

Furthermore, the weight average molecular weight of this acrylic oligomer is 50,000 or less, preferably in the range of 10,000 to 30,000.
The glass transition temperature (Tg) of such an acrylic oligomer (B) is usually -40 to 15
It is 0 degreeC, Preferably it is 0-100 degreeC. The components can be selected and used so that the glass transition temperature (Tg) calculated by the Fox equation is within the above range.

The amount of the functional group-containing monomer in 100 parts by weight of the monomer forming the acrylic oligomer (B) is 0.1 to 25 parts by weight, preferably 2 to 10 parts by weight.
Such an acrylic oligomer (B) can be produced by various methods similar to the production of the acrylic polymer (A), but can be produced by a solution polymerization method.

In this case, the organic solvent used in the production of the acrylic polymer (A) can be used as the solvent to be used.
When the acrylic oligomer (B) is produced by solution polymerization, the solid content concentration in the reaction solvent is usually 30 to 60%, preferably 40 to 55%.

In this invention, the hardening | curing agent which reacts with the functional group in the said acrylic polymer (A) and an acrylic oligomer (B) is mix | blended.
The curing agent used in the present invention is a curing agent having a shortest functional group molecular weight of 600 or more, preferably a shortest functional group molecular weight in the range of 650 to 2000, expressed by molecular weight / number of functional groups.

For example, when the functional group in the acrylic polymer (A) and the acrylic oligomer is a hydroxyl group, an isocyanate compound can be used as a curing agent.
In the present invention, when an isocyanate compound is used as the curing agent (C), the shortest functional group molecular weight represented by molecular weight / number of functional groups is 600 or more, preferably the shortest functional group molecular weight is in the range of 650 to 2000. An isocyanate compound can be used, and as such a curing agent (C), various forms of isocyanate compounds such as a burette type, an isocyanurate type, an adduct type, and a bifunctional prepolymer can be used.

In particular, in the present invention, for example, n-butyl methacrylate (nBMA); 30 parts by weight, t-butyl methacrylate (tBMA); 60 parts by weight: 2-isocyanatoethyl methacrylate (MOI): 5 parts by weight are added to the polymerization initiator. Acrylic polymer is formed in the presence, and 2-isocyanatoethyl methacrylate (MOI) is used to produce an acrylic copolymer having an -NCO group introduced.
By using 2-isocyanatoethyl methacrylate (MOI) or the like in this way, this M
The shortest functional group molecular weight can be adjusted by adjusting the copolymerization amount of OI.

  The pressure-sensitive adhesive layer for EMI film laminating of the present invention forms, for example, a pressure-sensitive adhesive layer for EMI film laminating by blending the acrylic polymer (A), acrylic oligomer, and curing agent (C) formed as described above. It can be set as the coating liquid at the time of carrying out.

  The pressure sensitive adhesive coating solution for EMI film lamination of the present invention is a film support obtained by removing the acrylic polymer (A) solution, acrylic oligomer (B) solution, and curing agent (C) solution prepared as described above. The film is applied to the surface of the film, and a film subjected to further peeling treatment is disposed on the coated surface and aged.

The EMI laminate film of the present invention is obtained by transferring the EMI film laminate pressure-sensitive adhesive layer thus prepared to, for example, a PET base film.
When preparing such an acrylic polymer (A) solution, an acrylic oligomer (B) solution, and a curing agent (C) solution, these blending amounts are as follows: acrylic polymer (A) solution, acrylic oligomer (B) ) Acrylic polymer (A) solution, acrylic oligomer (B) solution, curing so that the displacement amount of the micro compression test measured for the pressure-sensitive adhesive layer obtained from the solution and curing agent (C) solution is 15 μm / mN or more. The amount of the agent (C) solution is adjusted.

  Furthermore, the holding force change value obtained by the following formula from the difference between the holding force value at 80 ° C. measured by setting the conditions described in detail in the examples for the pressure-sensitive adhesive layer of the present invention, and the holding force value at 40 ° C. The blending amount of the acrylic polymer (A) solution, the acrylic oligomer (B) solution, and the curing agent (C) solution is set so as to be 0.01 or less.

(80 ° C. deviation length−40 ° C. deviation length) / tape width Normally, the blend ratio of the acrylic polymer (A) solution, acrylic oligomer (B) solution, and curing agent (C) solution is solid. In terms of minute conversion, acrylic oligomer (B): 3 to 30 parts by weight, preferably 5 to 20 parts by weight, curing agent: 0.5 to 5.0 parts by weight with respect to 100 parts by weight of acrylic polymer (A). Parts, preferably 1.0 to 3.0 parts by weight.

  The pressure-sensitive adhesive layer for EMI film laminate of the present invention is prepared by applying a pressure-sensitive adhesive layer-forming coating liquid containing the above components (A), (B) and (C) on a support. be able to. As the pressure-sensitive adhesive layer forming coating solution used at this time, a reaction solution in which each component is used for preparation can be used.

  Moreover, when preparing the adhesive layer for EMI film laminating of this invention, it is preferable to apply | coat the said coating liquid for adhesive layer formation on the support body by which the peeling process was carried out. The coating thickness at this time is usually 10 to 100 μm, preferably 20 to 50 μm in dry thickness. In addition, as the release-treated support used here, a peel-treated PET film or the like can be used.

  After applying the pressure-sensitive adhesive layer forming coating solution on the support thus peeled, the peeled support was placed on the surface of the formed coating layer, and the coating layer was peeled The pressure-sensitive adhesive layer for EMI film lamination of the present invention can be obtained by sandwiching between the supports and aging the pressure-sensitive adhesive layer usually for about 5 to 7 days.

  Furthermore, the EMI laminated film of the present invention can be obtained by peeling one of the peeled substrates from the EMI film laminating pressure-sensitive adhesive layer thus formed and transferring it to the surface of the transparent resin film. it can. A PET film etc. are used as a transparent resin film used here.

The pressure-sensitive adhesive layer for EMI film laminating and the EMI laminating film of the present invention can be directly transferred to the surface of a mesh pattern formed from a conductive metal such as copper. That is, the EMI film laminate pressure-sensitive adhesive layer of the present invention or the EMI laminate film having the pressure-sensitive adhesive layer transferred onto the surface of the transparent resin film as described above peels the peeled support to form a Cu mesh pattern. It can stick by making it closely_contact | adhere to the made support body surface and pressurizing under heating. In general, such thermocompression bonding is performed in an autoclave.

The temperature during the thermocompression bonding as described above is usually 50 to 70 ° C., the pressure is 3 to 5 atm, and the time is about 30 to 60 minutes.
Thus, after transferring and sticking on the surface of the pressure-sensitive adhesive layer of the present invention on the mesh pattern, the EMI laminate film of the present invention is used even when there is a defect on the sticking surface. By doing so, an adhesive layer can be removed from the surface of a mesh pattern, without damaging a mesh pattern. In the conventional EMI laminate film, once the transferred EMI laminate film is peeled off, the mesh pattern is transferred to the pressure-sensitive adhesive side. Although possible, according to the present invention, the adhesive layer for EMI film lamination and the EMI laminate film can be peeled without damaging the Cu mesh pattern.

  As described above, the pressure-sensitive adhesive layer for EMI film lamination and the EMI laminated film of the present invention can be peeled and removed from the surface of the mesh pattern once adhered without damaging the mesh pattern. Properties such as layer transfer performance and adhesive layer retention (cohesive strength) are not sacrificed. At the same time, by adjusting the holding force to a specific range, the movement of the pressure-sensitive adhesive layer is small even under mounting conditions, the transfer state at the time of bonding is maintained for a long time, and problems such as foaming do not occur.

The pressure-sensitive adhesive layer for EMI film laminating and the EMI laminating film of the present invention have the above-described configurations, but other configurations may be further added.
For example, in the pressure-sensitive adhesive layer for EMI film lamination or the EMI laminate film of the present invention having the above-described configuration, a layer having other characteristics can be disposed further inside these layers. For example, layers such as an infrared absorption layer, a far infrared absorption layer, a hard coat layer, an ultraviolet absorption layer, and a neon light absorption layer can be disposed.

〔Example〕
Hereinafter, examples of the pressure-sensitive adhesive layer for EMI film lamination and the EMI laminate film of the present invention will be described. However, the present invention is not limited thereto.

[Production of acrylic polymer (A-1)]
In a 4-necked flask capable of replacing nitrogen gas, n-butyl acrylate (BA): 55 parts by weight, methyl acrylate (MA) 40 parts by weight: cyclohexane dimethanol monoacrylate (CHDMAA) 5 parts by weight, toluene: 20 parts by weight Then, 20:20 parts by weight of ethyl acetate was charged, and the temperature of the above components charged in the reaction vessel was raised to 65 ° C. while replacing the air in the reactor with nitrogen gas.

Next, under stirring, 0.1 part by weight of azoisobutyronitrile (polymerization initiator, AIBN) was added to the reactor to initiate the polymerization reaction. Two hours after the start of polymerization, 0.1 part by weight of azoisobutyronitrile (AIBN) was further added, and further 0.2 hours after the start of polymerization.
An additional part by weight of azoisobutyronitrile (AIBN) was added and the polymerization reaction was carried out for a total of 7 hours.

Seven hours after the start of the polymerization, 150 parts by weight of ethyl acetate as a diluting solvent was added to the reaction solution to terminate the polymerization reaction, thereby producing an acrylic polymer (A-1) solution.
The acrylic polymer (A-1) thus obtained had a non-volatile content of 24.9%, a weight average molecular weight calculated by the GPC method of 700,000, and a glass transition temperature (Tg) determined from the Fox equation.
) Was -29 ° C.

[Production of acrylic oligomer (B-1)]
In a four-necked flask capable of replacing nitrogen gas, methyl acrylate (MA): 30 parts by weight, n-butyl methacrylate (nBMA): 65 parts by weight, 2-hydroxyethyl acrylate (2HEA): 5 parts by weight, and toluene: 100 parts by weight And methyl ethyl ketone (MEK): 20 parts by weight was charged, and the temperature of the above components charged in the reaction vessel was raised to 80 ° C. while replacing the air in the reactor with nitrogen gas.

Next, under stirring, 0.1 part by weight of azoisobutyronitrile (polymerization initiator, AIBN) was added to the reactor to initiate the polymerization reaction. Furthermore, after 20 minutes, 40 minutes, 60 minutes, 80 minutes, and 120 minutes after the start of polymerization, 0.1 parts by weight of azoisobutyronitrile (AIBN) was additionally added. After 4 hours, 0.2 part by weight of azoisobutyronitrile (AIBN) was additionally added, and the polymerization reaction was carried out for a total of 7 hours.

Seven hours after the start of the polymerization, 20 parts by weight of ethyl acetate as a diluent solvent was added to the reaction solution to terminate the polymerization reaction, thereby producing an acrylic oligomer (B-1).
The acrylic oligomer (B-1) solution thus obtained had a non-volatile content of 40.5%, a weight average molecular weight calculated by the GPC method of 40,000, and a glass transition temperature ( Tg) was 14 ° C.

[Production of curing agent solution K-1]
N-Butyl methacrylate (nBMA): 30 parts by weight, t-
Butyl methacrylate (tBMA): 65 parts by weight, 2-isocyanate ethyl methacrylate (MOI): 5 parts by weight and toluene: 100 parts by weight are charged into the reaction vessel while replacing the air in the reactor with nitrogen gas. The above components were heated to 80 ° C.

  Next, under stirring, 0.1 part by weight of azoisobutyronitrile (AIBN) was added to the reactor to initiate the polymerization reaction. Furthermore, after 20 minutes, 40 minutes, 60 minutes, 80 minutes, and 120 minutes after the start of polymerization, 0.15 parts by weight of azoisobutyronitrile (AIBN) was added, respectively. After 4 hours, 0.2 part by weight of azoisobutyronitrile (AIBN) was additionally added, and the polymerization reaction was carried out for a total of 7 hours.

Seven hours after the start of polymerization, 150 parts by weight of toluene as a diluent solvent was added to the reaction solution to terminate the polymerization reaction, thereby producing a curing agent solution (K-1).
The curing agent solution thus obtained had a non-volatile content of 40.5%, and the weight average molecular weight calculated by the GPC method was 20,000.

In the curing agent contained in the curing agent solution (K-1), 10.11 other monomers are polymerized with respect to one molecule of 2-isocyanate ethyl methacrylate (MOI), and accordingly, molecular weight / functional group number. The shortest functional group molecular weight represented by is 1591.

[Manufacture of adhesives]
The acrylic polymer solution (A-1), the acrylic oligomer solution (B-1), and the curing agent solution (K-1) are mixed into the solid content (acrylic polymer) in the acrylic polymer solution (A-1). Solid content (acrylic oligomer) in acrylic oligomer solution (B-1) with respect to 100 parts by weight
It became 5 weight part, and it mix | blended so that it might become 1.5 weight part of solid content (hardening agent) in hardening | curing agent solution (K-1), and obtained the adhesive solution.

As shown in FIG. 1 (a), the pressure-sensitive adhesive coating thickness of the dried PET film PET3811 (manufactured by Lintec Corporation) is 25 μm at 90 ° C. for 3 minutes by heating and drying. It was applied as follows. A release PET film PET38GS (manufactured by Lintec Co., Ltd.) was bonded to the surface of the pressure-sensitive adhesive layer thus applied and aged for one week at room temperature to form a pressure-sensitive adhesive layer for EMI film lamination (measurement sample: sheet A). .

[Measurement of holding power]
As shown in FIG. 1B, the holding force at 40 ° C. was measured as follows.
Peel PET38GS, which is a peeled PET film, from the above sheet A, and paste a 25 μm thick PET (product name: Lumirror S10) to the exposed adhesive layer to prepare a measurement sample (sheet B). Prepared. Cut from this sheet B to 20mm wide x 50mm long, peel off PET3811 which is peeled PET, and paste it on a SUS plate polished with No. 280 water-resistant abrasive paper so that the area is 20mm wide x 20mm long. 2 reciprocating pressure bonding.

Thereafter, the sheet was placed in a constant temperature dryer set to 40 ° C., and after 20 minutes, a weight of 1 kg was applied to the sheet, and the shift length of the sheet after 1 hour was measured.
The holding force at 80 ° C. was measured in the same manner as in the measurement of the holding force at 40 ° C., except that the set temperature of the constant temperature dryer was set to 80 ° C.

The ratio of the holding force value at 80 ° C. of the tape and the holding force value at 40 ° C. is
It was calculated by the following formula: (80 ° C deviation length−40 ° C deviation length) / tape width.

[Displacement of micro compression test]
As shown in FIG. 1 (d), the PET38GS is peeled off from the sheet A and pasted on 12 μm PET (trade name: Lumirror S10 manufactured by Toray Industries, Inc.), and the PET3811 is further peeled off to obtain the same 12 μm PET as above. To prepare a measurement sample C, and this measurement sample C is made into a micro compression tester (Shimadzu Corporation, MCT-W
Series) and the change in displacement due to load was measured. The displacement amount of the micro compression test in the present invention was determined by the following equation.

  Displacement amount of micro compression test = displacement (μm) / 2 (mN)

[optical properties]
As shown in FIG. 1 (e), PET38GS of sheet A was peeled off and 50 μm PET (manufactured by Toyobo Co., Ltd., trade name: Cosmo Shine A4300) was attached to prepare measurement sample D. A 25mm x 75mm EMI sheet was pasted on the slide glass, and PET3811 of the measurement sample D was peeled off from the EMI sheet.
A measurement sample D of 5 mm × 75 mm was bonded, and the measurement sample E was prepared by treatment under heat and pressure conditions of 50 ° C. × 5 kg / cm ² × 60 minutes using an autoclave.
For this measurement sample E, using a haze meter HM-150 (Murakami Color Research Laboratory Co., Ltd.), measure the total light transmittance according to JIS K 7361, and measure the haze according to JIS K 7136. did.

[Rework test]
The sample ED of the measurement sample E was peeled off by hand, and the appearance after peeling was observed.

[Mounting test]
The measurement sample E was held at 85 ° C. for 120 hours, and the appearance change thereafter was observed.
The properties measured as described above are shown in Table 1.

In Example 1, the amount of acrylic oligomer (B-1) used is 10 parts by weight with respect to 100 parts by weight of acrylic polymer (A-1), and the amount of curing agent <K-1> used is 2. An adhesive solution was prepared in the same manner except that the amount was 5 parts by weight, and an adhesive layer for EMI film lamination (sheet A) was formed in the same manner except that this adhesive solution was used.

Further, in the same manner as in Example 1, the holding force, the amount of displacement, and the optical characteristics were measured, and further, a rework test and a mounting test were performed.
The results are shown in Table 1.

In Example 1, an adhesive solution was prepared in the same manner except that 1.7 parts by weight of the curing agent TSE100 was used instead of the curing agent (K-1), and the same except that this adhesive solution was used. Thus, an EMI film laminating pressure-sensitive adhesive layer (sheet A) was formed. This curing agent TSE
100 is an isocyanurate compound (trade name: DURANATE ^™ TSE-100) manufactured by Asahi Kasei Chemical Co., Ltd., has a molecular weight of 1050 and a shortest functional group molecular weight of 700.

Further, in the same manner as in Example 1, the holding force, the amount of displacement, and the optical characteristics were measured, and further, a rework test and a mounting test were performed.
The results are shown in Table 1.

[Comparative Example 1]
In Example 1, a pressure-sensitive adhesive solution was prepared in the same manner except that the acrylic oligomer (B-1) was not used, and the pressure-sensitive adhesive layer for EMI film lamination was similarly prepared except that this pressure-sensitive adhesive solution was used. (Sheet A) was formed.
Further, in the same manner as in Example 1, the holding force, the amount of displacement, and the optical characteristics were measured, and further, a rework test and a mounting test were performed.
The results are shown in Table 1.

[Comparative Example 2]
In Example 3, the curing agent TSE100 was used without using the acrylic oligomer (B-1).
A pressure-sensitive adhesive solution was prepared in the same manner except that the amount used was 1 part by weight, and a pressure-sensitive adhesive layer (sheet A) for EMI film lamination was formed in the same manner except that this pressure-sensitive adhesive solution was used.
Further, in the same manner as in Example 3, the holding force, the amount of displacement, and the optical characteristics were measured, and further, a rework test and a mounting test were performed.
The results are shown in Table 1.

[Comparative Example 3]
In Example 1, in place of the curing agent <K-1>, the molecular weight is 656, and the shortest functional group molecular weight expressed by molecular weight / number of functional groups is 437.3. A pressure-sensitive adhesive solution was prepared in the same manner except that 0.9 part by weight of the isocyanate compound was used, and a pressure-sensitive adhesive layer (sheet A) for EMI film lamination was formed in the same manner except that this pressure-sensitive adhesive solution was used. .
Further, in the same manner as in Example 1, the holding force, the amount of displacement, and the optical characteristics were measured, and further, a rework test and a mounting test were performed.
The results are shown in Table 1.

[Comparative Example 4]
In [Production of acrylic polymer (A-1)] in Example 1, acrylic polymer (A
-1) is prepared in the same manner except that the amount of toluene initially placed in the reaction vessel is changed from 20 parts by weight to 60 parts by weight and the amount of ethyl acetate is changed from 130 parts by weight to 90 parts by weight. -Based polymer (A-2) was produced. The resulting acrylic polymer (A-2) solution had a non-volatile content of 24.8%, and the obtained acrylic polymer (A-2) was GPC.
The weight average molecular weight calculated by the method was 400,000.

In Example 1, instead of using 100 parts by weight of the acrylic polymer (A-1) solution in terms of solid content, the acrylic polymer (A-2) solution obtained as described above was converted to 100 in terms of solid content. An adhesive solution was prepared in the same manner except that parts by weight were used, and an adhesive layer for EMI film lamination (sheet A) was formed in the same manner except that this adhesive solution was used.
Further, in the same manner as in Example 1, the holding force, the amount of displacement, and the optical characteristics were measured, and further, a rework test and a mounting test were performed.
The results are shown in Table 1.

[Comparative Example 5]
In Example 1 [Production of acrylic oligomer (B-1)], the same procedure was carried out except that 20 parts by weight of MEK initially placed in the reaction vessel was changed to ethyl acetate when the acrylic polymer (A-1) was produced. Thus, an acrylic oligomer (B-2) was produced. The nonvolatile content of the obtained acrylic oligomer (B-2) solution was 41.2%, and the weight average molecular weight calculated by the GPC method for the obtained acrylic oligomer (B-2) was 80,000.

In Example 1, instead of using 5 parts by weight of the acrylic oligomer (B-1) solution in terms of solid content, the acrylic oligomer (B-2) solution obtained as described above was converted to 5 in terms of solid content. An adhesive solution was prepared in the same manner except that parts by weight were used, and an adhesive layer for EMI film lamination (sheet A) was formed in the same manner except that this adhesive solution was used.
Further, in the same manner as in Example 1, the holding force, the amount of displacement, and the optical characteristics were measured, and further, a rework test and a mounting test were performed.
The results are shown in Table 1.

  The pressure-sensitive adhesive layer for EMI film laminating and the EMI laminated film of the present invention use a curing agent having a specific shortest functional group molecular weight in the pressure-sensitive adhesive layer, and the displacement range in the micro compression test is within a specific range. By determining the composition so as to become, it is possible to enhance the fluidity during lamination and to improve the transferability to the mesh surface-shaped adhesive layer after lamination.

  Furthermore, the adhesive layer for EMI film lamination and EMI laminate film of this invention can peel the EMI film stuck on the mesh surface, for example, when the sticking defect with respect to EMI film is discovered after lamination. Moreover, despite the fact that the pressure-sensitive adhesive layer for EMI film lamination and the EMI laminated film of the present invention have reworkability, the transferability of the pressure-sensitive adhesive layer is very good, and the holding power is within a specific range. By adjusting, the movement of the pressure-sensitive adhesive layer is small even under mounting conditions, the transfer state at the time of sticking is stably maintained for a long time, and problems such as foaming do not occur.

FIG. 1 shows a film configuration used in the characteristic test of the present invention.

Claims (4)

A repeating unit having a functional group is added in an amount of 0.1 to 10 in 100 parts by weight of the acrylic polymer (A).
An acrylic polymer (A) containing in an amount of parts by weight, having a weight average molecular weight of 500,000 or more and a glass transition temperature (Tg) of −20 ° C. or less;
An acrylic having a repeating unit having a functional group capable of reacting with the curing agent (C) in an amount of 0.1 to 25 parts by weight and having a weight average molecular weight of 50,000 or less in 100 parts by weight of the acrylic oligomer (B). Oligomer (B),
and,
Containing a curing agent (C) having a shortest functional group molecular weight of 600 or more represented by molecular weight / number of functional groups,
The displacement amount of the micro compression test measured for the pressure-sensitive adhesive layer obtained from the components (A), (B) and (C) is 15 μm / mN or more,
Ratio of holding power value at 80 ° C. per unit width of the tape having the pressure-sensitive adhesive as a pressure-sensitive adhesive layer and holding power value at 40 ° C. per unit width of the tape (80 ° C. holding power value−40 ° C. holding power value) ), The acrylic polymer (A), the acrylic oligomer (B), and the curing agent (C) are blended such that the pressure-sensitive adhesive layer for EMI film lamination is 0.01 or less.   The functional group contained in the acrylic oligomer and the functional group contained in the acrylic oligomer are the same functional group, and the functional group is a hydroxyl group. The adhesive layer for EMI film lamination of description. On the support film surface,
A repeating unit having a functional group is added in an amount of 0.1 to 10 in 100 parts by weight of the acrylic polymer (A).
An acrylic polymer (A) containing in an amount of parts by weight, having a weight average molecular weight of 500,000 or more and a glass transition temperature (Tg) of −20 ° C. or less;
In 100 parts by weight of the acrylic oligomer (B), it has a repeating unit having a functional group capable of reacting with the curing agent (C) described later in an amount of 0.1 to 25 parts by weight, and has a weight average molecular weight of 50,000 or less. An acrylic oligomer (B),
and,
Containing a curing agent (C) having a shortest functional group molecular weight of 600 or more represented by molecular weight / number of functional groups,
The displacement amount of the micro compression test measured for the pressure-sensitive adhesive layer obtained from the components (A), (B) and (C) is 15 μm / mN or more,
Ratio of holding power value at 80 ° C. per unit width of the tape having the pressure-sensitive adhesive as a pressure-sensitive adhesive layer and holding power value at 40 ° C. per unit width of the tape (80 ° C. holding power value−40 ° C. holding power value) ) That the pressure-sensitive adhesive layer for the EMI film laminate is formed by blending the acrylic polymer (A), the acrylic oligomer (B), and the curing agent (C) so that it is 0.01 or less. Characteristic EMI laminate film.   The functional group contained in the acrylic oligomer and the functional group contained in the acrylic oligomer are the same functional group, and the functional group is a hydroxyl group. The EMI laminate film described.

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