JP2001266759A - Impact relaxing laminate, and flat panel display unit and plasma display unit using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact relaxing laminate, that is thin and lightweight, and high in crack-proofing nature of the panel and a flat panel display using it, particularly a plasma display unit, by integrating a glass scatter-preventing layer and impact-relaxing layer directly to an image display panel via a transparent adhesive. SOLUTION: On a glass substrate 4 of the flat panel display, that is broken by an impact force corresponding to 79,000 N, when a steel ball of 510 g falls freely from a height of 1.5 m, two kinds of transparent laminates with different (shear) elastic moduli are formed via transparent adhesive layers 3. They are formed in a sequence of the adhesive layer/a crack-preventing layer, having a high shear elastic modulus B/a scatter-preventing layer with a high shear elastic modulus A, and for the two laminates, a shear elastic modulus of the layer A is 2×108 (Pa) or higher and that of the layer B is in the range of 1×104-2×108 (Pa).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display (hereinafter abbreviated as "FPD"), in particular, a PDP (Plasma Display Panel) and a PALC (Plasma Display Panel) which have a thin glass substrate and are easily broken, which are attracting attention as large displays. Plasma-addressed liquid crystal), FED (field emission display),
A transparent shock-absorbing laminate is bonded to a flat panel display glass substrate such as an LCD (liquid crystal display) via a transparent adhesive layer to reduce the impact force caused by falling of a steel ball equivalent to 79000N, thereby preventing scattering and cracking. The present invention relates to an impact-mitigating laminate having a preventive property and a flat panel display device formed with the same.

[0002]

2. Description of the Related Art Glass cathode ray tubes (cathode ray tubes (CR)
T)) is a safety standard (U
The L standard, the Radio Control Law, etc.) stipulate that the impact resistance test by dropping a steel ball prevents splashing and does not penetrate (no electric shock with a size larger than the finger hole), and it is necessary to design a thick panel glass was there. Such a CR
Regarding the T glass panel, as a means of reducing the weight of the glass panel without increasing the thickness of the glass panel, a glass cathode ray tube laminated with a self-healing synthetic resin protective film (thermosetting urethane resin and polyethylene terephthalate film (PET)) There are proposals in JP-A-6-333515 and JP-A-6-333517.

[0003] However, although the scattering prevention property is improved, the crack prevention property of the glass panel substrate is not improved.

As a protective filter, Japanese Patent Application Laid-Open No.
JP-A-174206 proposes protecting the glass of the panel itself with a front protective substrate in which a transparent resin sheet is set within 10 mm of the display to protect the internal glass substrate of the flat panel display (various LCDs and PDPs). Have been.

However, in this configuration, since an air layer enters between the glass panel and the protective substrate, there are many problems such as double reflection of external light, an increase in reflectance, and a decrease in sharpness of image quality. there were. In addition, dust and
Tobacco stains and the like were accumulated, and cleaning was also difficult. Furthermore, in the field of FPDs where it is important to increase the size and the weight, there is a tendency to reduce the thickness of the panel itself, and installing a protective filter away from the panel has an adverse effect. That is, in the above-described known technology, a thin, lightweight protective filter for preventing cracking of a panel, which is applicable to a large-sized display in the FPD field, has not yet been realized.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems by providing PDP, PALC, FED, LC
D directly on the image display panel such as D via a transparent adhesive layer,
An object of the present invention is to provide a thin and lightweight shock-mitigating laminate having a high panel crack-preventing property and a flat panel display device using the same by integrating a glass scattering prevention layer and a shock-mitigating layer.

[0007]

In order to achieve the above-mentioned object, the impact relaxation laminate of the present invention comprises 510 g of a steel ball.
Two types having different (shear) elastic moduli through a transparent adhesive layer on a glass panel substrate of a flat panel display that is destroyed by an impact force equivalent to 79000 N when dropped freely from a height of 5 m. , And the above-mentioned pressure-sensitive adhesive layer / high shear modulus B crack prevention layer / high shear modulus A scattering prevention layer are formed in this order. Rate is 2 × 10 ⁸
(Pa) or more, and the shear modulus of the B layer is 1 × 10 ⁴ or more.
It is characterized by a range of 2 × 10 ⁸ (Pa).

[0008] In the impact relaxation laminate, 7900
It is preferable to reduce the impact force of the steel ball falling, which corresponds to the impact force of 0N, to 50% or less.

[0009] In the shock-absorbing laminate, the total thickness of the two transparent laminates and the transparent adhesive is 1 mm or less;
In addition, the visible light transmittance is preferably 60% or more.

Next, in the flat panel display device of the present invention, a transparent shock absorbing laminate including two types of transparent laminates having different shear elastic moduli is bonded to the front surface of the flat panel display via the transparent adhesive layer. It is characterized by having.

Next, in the plasma display device of the present invention, a transparent shock absorbing laminate including two types of transparent laminates having different shear elastic moduli via the transparent pressure-sensitive adhesive layer according to any of the above is applied to a plasma display panel. It is characterized by being directly bonded.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies, the present inventors have made a steel ball of about 510 g fall freely from a height of 1.5 m from a height of 1.5 m by actually referring to a safety standard. 79000N was measured. Further, a destructive test was performed on the glass substrate for FPD by dropping a steel ball, and a limit impact force (or an impact force that does not break) at which the glass substrate was broken was measured. The impact force relaxation (reduction) rate was determined as to the extent to which the impact force should be reduced by the impact relaxation laminate with respect to the limit impact force at which the crack occurs. That is, the shock-absorbing laminate has a configuration in which the anti-scattering agent / anti-cracking agent is bonded to the glass substrate via the transparent pressure-sensitive adhesive layer in this order, and the anti-scattering layer has a shear modulus (G ′) of 2 × 10 ^By setting it to ⁸ (Pa) or more, the damage of the relaxation laminate itself is eliminated, the glass has a function of preventing scattering, and the shear relaxation modulus (G ′) of the shock relaxation layer is 1 × 10 ⁴ to 2 × 10 ^{4. By} setting the pressure to ⁸ (Pa), a function of preventing cracking of the glass substrate was provided. Further, as the above-mentioned laminate, an impact-mitigating laminate equivalent to relaxing the impact force to 50% or less with a shock force of 79000N obtained by dropping a 500 g steel ball from a height of 1.5 m as 100% is placed on a glass substrate. When formed through a transparent pressure-sensitive adhesive, the present inventors have found an impact-mitigating laminate that has good scattering prevention and does not break the glass substrate, and has completed the present invention.

That is, the present invention forms a transparent laminate having two types of shear modulus on a glass panel substrate of FPD via a transparent pressure-sensitive adhesive layer. 5 free fall impact forces of 79000N
An object of the present invention is to provide a shock-mitigating laminate characterized by preventing scattering and cracking, which are reduced to 0% or less, and a flat panel display using the same.

Hereinafter, a specific configuration of the present invention will be described. FIG. 1 shows a cross-sectional view of an impact relaxation laminate according to one embodiment of the present invention. In FIG. 1, the scattering prevention layer 1 and the shock absorbing layer 2
And an adhesive layer 3 and an FPD panel glass substrate 4.

The scattering prevention layer 1 has a visible light transmittance of 7
0% or more, and excellent in transparency and mechanical strength and excellent in heat resistance, such as polyester resin, (meth) acrylic resin, polycarbonate (P
C) resin, polyethylene naphthalate (PEN) resin,
A film made of polyethylene terephthalate (PET) resin, triacetyl cellulose (TAC), ARTON resin, epoxy resin, polyimide resin, polyetherimide resin, polyamide resin, polysulfone, polyphenylene sulfide, polyethersulfone, or the like is used. . This transparent film substrate may be a single layer or a composite layer of two or more layers.

In particular, as a mechanical property that is important for preventing scattering, that is, for preventing breakage, it is necessary that the shear modulus G ′ in dynamic viscoelasticity measurement is 2 × 10 ⁸ (Pa) or more. Below this, when a scattering prevention layer is formed on a FPD panel glass substrate via a transparent pressure-sensitive adhesive layer, 51
Destruction is caused by free fall by a 0 g steel ball, that is, the ball is broken, the hole is not sufficiently scattered, and there is a problem of electric shock due to the hole.

The above-mentioned shear modulus is a measured value of the shear modulus G 'at 25 ° C. ± 3 ° C. at a frequency of 1 Hz using a dynamic viscoelasticity measuring apparatus DMS120 manufactured by Seiko Instruments Inc. In general, there is a relation of tensile elastic modulus E = 3G ′ (shear elastic modulus), and the tensile elastic modulus E is about three times the above-mentioned shear elastic modulus G ′.

The anti-scattering layer is structurally located on the outermost surface of the FPD. Therefore, in order to suppress the deterioration of the FPD image display, a known anti-reflection property of 5% or less, preferably 3% or less, is used. Alternatively, an anti-glare treatment with a haze of 5% or less may be performed to prevent reflection of external light. Furthermore, as a surface protection function, the surface (pencil) hardness is H
As described above, antifouling treatment may be performed to prevent contamination such as fingerprint adhesion.

As described above, as the scattering prevention layer,
It is necessary to have a shear modulus that does not break it, but in addition to that, it is formed on the outermost surface side and is involved in the image characteristics and surface function of the FPD. Therefore, surface hardness treatment, low reflection prevention treatment, reflection prevention treatment, electromagnetic wave shielding treatment In addition, since coating by a known technique such as antistatic treatment and contamination prevention treatment and vacuum thin film forming treatment are required, heat resistance of 80 ° C. or more is required.

Next, the anti-cracking layer 2 has a visible light transmittance of 60% or more, is excellent in transparency, and has a shear elastic modulus G ′ of 1 × 10 ⁴ (Pa) to 2 due to dynamic viscoelasticity. ×
It is preferably in the range of 10 ⁸ (Pa).

[0021] That is, in the 1 × 10 ⁴ (Pa) less than the shear modulus, hardly processed during punching and cutting a sheet of too soft, there are problems such as protrusion of the edge portion.

On the other hand, when the pressure exceeds 2 × 10 ⁸ (Pa), the effect of alleviating the impact force of 79000 N decreases, and the FPD
Glass substrate is broken. In addition, there is a problem that the thickness which does not crack becomes as thick as 1 mm or more only with the crack prevention layer.

Examples of such a transparent crack-preventing layer include an ionomer resin in which ethylene-methacrylic acid copolymer molecules are cross-linked with metal ions (Na ⁺ , Zn ^2+, etc.);
Thermoplastic resins such as VA (ethylene-vinyl acetate copolymer), PVC (polyvinyl chloride), EEA (ethylene acrylate copolymer), PE (polyethylene), PP (polypropylene), polyamide resin, polybutyral resin, polystyrene resin, and polystyrene resins , Polyolefin, polydiene, PVC, polyurethane, polyester, polyamide, fluorine, chlorinated polyethylene, polynorbornene, polystyrene
Thermoplastic elastomers showing rubber elasticity such as polyolefin copolymers, (hydrogenated) polystyrene / butadiene copolymers, polystyrene / vinyl polyisoprene copolymers, or thermoplastic elastomers to polyolefins such as polyethylene and polypropylene Blends and the like can also be used.

Further, polyolefin (polypropylene (PP) or polyethylene (PE), etc.) / Thermoplastic resin (EVA) / polyolefin, polyolefin (PP or PE) / polyolefin + thermoplastic elastomer / polyolefin (PP or PE) or PP / PE / PP or the like, a multilayer laminate in which the blend ratio of polyolefin + thermoplastic elastomer is changed, a laminate in which a polyolefin is blended with a thermoplastic elastomer, and the like can also be used.

The impact relaxation layer can also be formed by directly laminating one side of the scattering prevention layer by thermal lamination or by coating a dissolved resin.

Next, the transparent pressure-sensitive adhesive layer 3 has an acrylic
There are rubber-based and polyester-based adhesives, and it is particularly preferable to use an acrylic adhesive having high transparency. The acrylic pressure-sensitive adhesive is an acrylic polymer, that is, as a main component monomer mainly for imparting appropriate wettability and flexibility to the pressure-sensitive adhesive, and has a glass point transfer (Tg) of the polymer of 60 ° C. or less. 1 alkyl (meth) acrylate
Using a proper polymerization catalyst, a solution polymerization method, an emulsion polymerization method, a bulk polymerization method (particularly, ultraviolet irradiation) Polymerization method), and a suspension polymerization method. Use is made of such an acrylic copolymer, which contains various known additives. A thermal crosslinking type, a light (ultraviolet ray, electron beam) crosslinking type, or the like may be used.

Since the transparent pressure-sensitive adhesive layer is directly bonded to an FPD glass substrate, it needs to have both pressure-sensitive adhesive strength and reworkability.
⁴ (Pa) to 1 × 10 ⁷ (Pa) is preferable. Furthermore, the thickness of the pressure-sensitive adhesive layer is from 10 μm to
A range of 500 μm is good. If it is too thin, the adhesive properties will not be satisfactory, and if it is too thick, problems will occur such as glue sticking out of the edge during sheeting.

The thickness of the scattering prevention layer is preferably in the range of 10 μm to 600 μm from the viewpoint of damage prevention. If the thickness is 10 μm or less, there is a problem of being damaged by an impact force of 79000 N.
If it is more than 00 μm, the thickness of the crack preventing layer and the pressure-sensitive adhesive layer becomes too thin, and the crack preventing property cannot be satisfied.

The thickness of the crack preventing layer is 100 μm to 1 μm.
700 μm is preferred. If the thickness is thin, the impact relaxation property is reduced and the glass plate is broken. On the other hand, if the thickness is large, the price is increased and the transparency is reduced.

The total thickness of the above-mentioned anti-scattering layer, impact-absorbing layer and transparent pressure-sensitive adhesive layer is 2 mm or less, particularly 1 mm or less, from the viewpoint of deterioration of the image quality of the FPD. Further, the transmittance of the above three layers is preferably 60% or more, more preferably 70% or more, from the viewpoint of preventing image quality deterioration.

Further, in the order of the three-layer structure, an FPD glass substrate / a transparent pressure-sensitive adhesive layer / a crack prevention / scatter prevention layer is essential. If the crack-preventing layer and the scattering-preventing layer are reversed, the crack-preventing layer does not have heat resistance and cannot be subjected to surface treatment such as low-reflection prevention, and the relaxation layer is damaged by falling of 79000N steel balls.

Next, regarding the impact force measurement of a steel ball free fall,
At room temperature (23 ± 3) when a 510 g steel ball having a diameter of about 50 mm was dropped from a height of 1.5 m using the apparatus shown in FIG.
C)).

A crack preventing layer and a scattering preventing layer were formed on the force sensor of the impact force measuring device shown in FIG. 2 with an adhesive therebetween, and a steel ball having a diameter of 50 mm and a weight of about 510 g was 1.5 m long.
After dropping from the height, the impact force F1 <N> at that time was measured, and the extent to which the impact force was reduced was measured.

As the impact reduction rate, the impact relaxation rate R
1 = (F1 / F0) × 100.

Next, as a glass substrate for a plasma display (PDP), which is considered to be particularly vulnerable to impact among FPD panels, high strain point glass (PD200, elastic modulus 7.6 × 10 ¹⁰ (Pa)) Was selected, and a glass substrate having a thickness of 2.8 mm and a size of 30 cm × 30 cm was used as a test glass substrate.

Regarding the crack test of the glass substrate, an AL plate (300 × 300 mm, t
= 2 mm) on a glass substrate PD200 (t = 2.8 m).
m, 300 mm x 300 mm), put one or two sheets, and sandwich the upper and lower windows with an AL plate (plate with a thickness of 2 mm), fix the four sides, drop the steel ball on the center of the glass substrate, A crack test was performed. Table 1 shows the results.

[0037]

[Table 1] According to the glass substrate cracking test shown in Table 1, when the impact strength at which the glass plate is broken is constant at a steel ball weight of 510 g ± 20 g, a single glass is broken at 60 cm or more, that is, the impact strength is about 36000N. Then, in the case of a two glass substrate structure, the glass substrate breaks at a height of 30 cm or more, that is, the impact force 210
Cracked by more than 00N. That is, in order to design the glass plate so as not to break, when the above-mentioned impact relaxation laminate is formed on a glass substrate via an adhesive layer, the impact force that does not break is 5%.
When the weight of the 10 g steel ball is fixed, it is preferably 36000 N or less, more preferably 21000 N or less.

That is, from Table 1, the shock relaxation rate R0 (%) at which the glass substrate is not cracked is 50% or less, preferably 25%.
% Can be designed.

Regarding the above steel ball drop test, UL141
8 (approximately 540 g x 1.3 m height pendulum drop), UL19
In safety standards such as 50 (500 g × 1.3 m height pendulum drop) and the Electricity Control Law (500 g × 1.5 m), the evaluation of the anti-scattering property after the steel ball drop test is based on the number, size,
Although the distance is specified and the finger-sized hole does not open (does not penetrate) because there is no electric shock,
Apart from this, it is a problem if the expensive FPD panel is actually broken. Therefore, by actually measuring the impact force of the 510 g steel ball falling from a height of 1.5 m to break the glass substrate and designing a structure that does not break due to the formation of the impact relaxation laminate, scattering prevention and safety ( The design of the shock-mitigating laminate that does not crack the panel other than that which does not cause electric shock has been clarified. That is, in the present invention, the impact force of 79,000 N dropped from a steel ball having a height of 1.5 m and about 500 g is reduced by 50% or less, preferably 2%.
The glass substrate is not broken by forming the impact-relaxing laminate having an impact-mitigating force corresponding to the reduction to 5% or less. (1) Design of an impact relaxation laminate that does not break the glass substrate F2 (glass fracture impact force) ≧ F1 (impact force by the impact relaxation laminate) <N> R0 (glass fracture impact relaxation rate) ≧ R1 (impact relaxation laminate) (%) (2) Falling ball impact test using steel ball As shown in FIG. 4, a glass substrate (high strain point glass: PD200 made by Asahi Glass, size (300 mm × 300 mm, t
= 2.8 mm), a shock-absorbing laminate (impact-absorbing layer and anti-scattering layer) is formed via a transparent adhesive, and 500 g of steel balls are dropped from a height of 1.5 m to the center of the laminate to prevent scattering. The property (breakage prevention property) and the cracking property of the glass substrate were visually evaluated.

As described above, the impact relaxation force F1 (N) is obtained by forming the adhesive + impact relaxation laminate on the force sensor as described above.
The measurement was performed using a T analyzer (see FIG. 2). The impact force F2 (N) actually broken in the glass break test shown in FIG. 4 and the shock relaxation force F1 due to the formation of the transparent relaxation laminate are respectively prevented from glass breakage with respect to the impact force F0 (N) caused by the steel ball falling. The relaxation rates were obtained as R0 and R1. R0 (%) (F2 / F0) × 100, R1 (%)
(F1 / F0) × 100 Next, a specific description will be given with reference to examples of the present invention.

The transmittance is a spectrophotometer U-34 manufactured by Hitachi, Ltd.
Measured at 10. The visible light transmission shown in the examples is a measured value at a wavelength of 550 nm. "Measurement of Shear Elasticity by Dynamic Viscoelasticity Apparatus" Using a dynamic viscoelasticity apparatus DMS120 manufactured by Seiko Instruments, shear elasticity at 25 ° C. ± 3 ° C. as a sample of 5 mm × 10 mm under a fixed condition of frequency 1 Hz by temperature dispersion. The rate G 'was measured.

[0042]

Example 1 Polyethylene terephthalate (PET,
G ′ 1.4 × 10 ⁹ Pa) In a scattering prevention layer film (OX69K manufactured by Mitsubishi Chemical Corporation, thickness: 175 μm), PP / EVA / PP (POVIC-T manufactured by Achilles;
800 μm G ′ 6.9 × 10 ⁷ Pa) The laminated film was heat-laminated, and then a T (molecular weight (Mw: about 1.5 million)) T composed of a copolymer of butyl acrylate and acrylic acid was used.
g acrylic adhesive (G ′ 7.7 × 10 ⁴ ) at about −20 ° C.
Pa) of 25 μm. The thus-prepared shock-absorbing laminate with a transparent pressure-sensitive adhesive is applied to a high strain point glass substrate (PD).
200, thickness 2.8mm, 300mm x 300m
m).

Next, the glass plate cracking test configuration shown in FIG.
A steel ball drop test was performed on a single piece type. As a steel ball drop condition, 510 g having a diameter of 50 mm was used and dropped from a height of 1.5 m to the center of the glass substrate.

The impact relaxation force due to the steel ball falling in the above-mentioned constitution of the adhesive layer / impact relief layer / scatter prevention layer was measured by using a force sensor device shown in FIG. The transmittance of the glass substrate provided with the shock absorbing laminate is 80%.
Furthermore, the total thickness of the shock-mitigating laminate including the adhesive is 1000
μm. With this thickness, even when directly attached to the FPD panel, deterioration of image quality by visual observation was not recognized.

[0045]

Example 2 Example 1 was repeated except that the thickness of the crack prevention layer was changed to 600 μm. The visible light transmittance of the glass substrate provided with the impact relaxation laminate was 80%.
Furthermore, the total thickness of the impact-reducing laminate including the adhesive is 800 μm.
m.

[0046]

Example 3 An ionomer resin film 800 μm (Himilan 1 manufactured by Du Pont-Mitsui Chemicals) was used as an impact relaxation layer.
601, G ′ 1.2 × 10 ⁸ Pa) The procedure was the same as in Example 1 except that the film was changed. The visible light transmittance of the glass substrate provided with the shock absorbing laminate is 80%, and the total thickness is 1%.
000 μm.

[0047]

Example 4 As a shock absorbing layer, Cleartec H800
Example 1 was the same as that in Example 1 except that the film was changed to a film having a thickness of 3.1 μm (G ′ 3.1 × 10 ⁷ Pa) with the addition of styrene / vinyl / isoprene elastomer “Hybler” (trade name) to polyvinylene manufactured by Kuraray Trading Co., Ltd. The transmittance of the glass substrate provided with the shock absorbing laminate is 72%, and the total thickness is 10%.
It was 00 μm.

[0048]

Fifth Embodiment Urethane: 800 μm as Impact Shock Absorbing Layer
(Seedum DUS605 non-yellowing type, G '4.6 ×
10 ⁷ Pa) According to Example 1, except that the film was changed. The transmittance of the glass substrate provided with the shock absorbing laminate is 7
5%, and the total thickness was 1000 μm.

[0049]

Comparative Example 1 Polyethylene terephthalate (PET) scattering prevention layer film (OX69K, thickness 175, manufactured by Mitsubishi Chemical Corporation)
Example 1 except that an acrylic pressure-sensitive adhesive having a molecular weight (Mw of about 1.5 million) and a Tg of about -20 ° C was formed on the acrylic adhesive having a molecular weight (Mw of about 1.5 million) and a shock absorbing layer was removed. According to. This adhesive scattering prevention P
ET high strain point glass (PD200) substrate has a transmittance of about 8
5%, and the total thickness was 200 μm.

[0050]

Comparative Example 2 An EVA film (EVA manufactured by Du Pont-Mitsui Chemicals Co., Ltd.) was used, except for the PET film of Example 1
(VA 10%), 200 μm G ′ 5 × 10 ⁷ Pa) was adhered to Example 1 except that only high strain point glass (PD200) was directly bonded.

[0051]

Comparative Example 3 A PET film having a thickness of 1,000 μm, an acrylic adhesive having a molecular weight (Mw of about 1.5 million) and a Tg of about −20 ° C. and a molecular weight (Mw of about 1.5 million) formed of a copolymer of butyl acrylate and acrylic acid was formed to a thickness of 25 μm. (PD200)
Example 1 was followed except that the contact was made directly.

The above results are shown in Tables 2 and 3.

[0053]

[Table 2]

[0054]

[Table 3] As described above, according to the embodiment of the present invention, 510
g The impact force of a steel ball dropped from a height of 1.5 m is 7900.
0N, the impact force is reduced to 50% or less by sequentially forming two types of impact-mitigating layers and shear-preventing layers having different shear elasticities via a transparent adhesive on the FPD glass panel substrate to be broken. It is possible to realize an impact-mitigating laminated body that is alleviated and has both scattering prevention and crack prevention. Further, since the above-mentioned laminate is formed directly on the glass substrate via the transparent adhesive, there is no void and double reflection of external light and accumulation of dirt are eliminated. Further, the impact relaxation laminate of the present invention has a transmittance of 60% or more, preferably 70% and a total thickness of 2 mm or less, and does not impair the image characteristics of the FPD panel. Including a flat panel display.

[0055]

According to the present invention, PDP, PALC, FED,
By bonding an impact-mitigating laminate composed of a scattering prevention layer and a crack prevention layer directly to an FPD panel such as an LCD via a transparent pressure-sensitive adhesive layer, glass scattering prevention and crack prevention are prevented, and glass is prevented. Improves image clarity by directly bonding to the panel itself, furthermore, there is no air layer between the panel and the shock absorbing sheet, no double reflection of external light, and no dust or dirt adheres to FPD. An impact relaxation laminate can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an impact relaxation laminate according to one embodiment of the present invention.

FIG. 2 is an explanatory view showing a method for measuring the impact force of a steel ball free fall according to one embodiment of the present invention.

FIG. 3 is a graph showing the results of measuring the impact force of a steel ball free fall according to one embodiment of the present invention.

FIG. 4 is an explanatory view showing a measuring method of a destructive test according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shatter prevention layer 2 Shock absorbing layer 3 Adhesive layer 4 FPD panel glass substrate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshitaka Nakamura 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Yukiko Azumi 1-1-1-2 Shimohozumi, Ibaraki-shi, Osaka No. F-term in Nitto Denko Corporation (reference) 4F100 AG00A AK07 AK25 AK42 AK68 AL01 BA04 BA10A BA10D GB48 JK07C JK07D JK10 JL03 JL13B JN01B YY00C YY00D 4G059 AA01 AB01 AB09 AB11 AB13 AC17 FA07 GA01 GA04 BB06 BB12 GG43 HH18

Claims (5)

[Claims] 1. A transparent pressure-sensitive adhesive layer is formed on a glass panel substrate of a flat panel display which is destroyed by an impact force equivalent to 79000 N when a 510 g steel ball is freely dropped from a height of 1.5 m. Thus, two kinds of transparent laminates having different shear modulus are formed, and the pressure-sensitive adhesive layer / high shear modulus B crack preventing layer / high shear modulus A scattering prevention layer are formed in this order. The two-layered laminate is characterized in that the shear modulus of the layer A is 2 × 10 ⁸ (Pa) or more, and the shear modulus of the layer B is in the range of 1 × 10 ⁴ to 2 × 10 ⁸ (Pa). Shock absorbing laminate. 2. The impact relaxation laminate according to claim 1, wherein the impact strength of the steel ball falling, which corresponds to an impact force of 79000 N, is reduced to 50% or less. 3. The impact relaxation laminate according to claim 1, wherein the total thickness of the two transparent laminates and the transparent pressure-sensitive adhesive is 2 mm or less, and the visible light transmittance thereof is 60% or more. 4. A transparent shock-mitigating laminate comprising two types of transparent laminates having different shear elastic moduli through the transparent pressure-sensitive adhesive layer according to any one of claims 1 to 3 on a front surface of a flat panel display. A flat panel display device. 5. A transparent shock-mitigating laminate comprising two types of transparent laminates having different shear elastic moduli via a transparent pressure-sensitive adhesive layer according to any one of claims 1 to 4, which is directly bonded to a plasma display panel. A plasma display device characterized by the above-mentioned.