JPH10140090A - Adhesive for cathode ray tube and cured material thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive for a cathode ray tube less in contraction in curing the same, and a cured material thereof. SOLUTION: This adhesive for a cathode ray tube consists of a component A: 95-30wt.% at least one or more kinds of (meth)acrylates selected form a group consisting of a urethane (meth)acrylate, an epoxy (meth)acrylate and a polyester (meth)acrylate, and a component B: 5-70wt.% polymer of at least one or more monomers selected from styrene, (meth)acylonitrile and a (meth) acrylic ester, and having >=500 number-average molecular weight. The adhesive preferably has 1.520-1.560 refractive index at 25 deg.C after curing thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube adhesive having a low shrinkage upon curing and a cured product thereof, and more particularly, to bonding a plastic film sheet to a surface of a cathode ray tube used for a television or various displays. The present invention relates to a cathode ray tube adhesive and a cured product thereof.

[0002]

2. Description of the Related Art In recent years, cathode ray tubes have been widely used for televisions and various displays. These cathode ray tubes are
Molten glass is molded and produced in a mold. However, since the surface of the panel glass becomes uneven during molding, polishing of the panel glass is indispensable. In order to streamline the polishing step and reduce the manufacturing cost, an ultraviolet-curable cathode ray tube adhesive is disclosed in JP-A-7-212171 and JP-A-8-127760.

[0003]

However, in these cathode ray tube adhesives, when cured by ultraviolet rays, the resin shrinks greatly, and the surface of the bonded plastic film sheet may be distorted. In addition, due to this shrinkage, a fine gap is formed at the interface with the panel glass,
As a result, there is a disadvantage that the image becomes difficult to see or looks flawed.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above problems can be solved by blending a specific (meth) acrylate and a specific polymer in a specific amount. Was completed.

That is, the present invention provides an adhesive for a cathode ray tube comprising the following components A and B. A component: 95 to 30% by weight of at least one or more (meth) acrylates selected from the group consisting of urethane (meth) acrylate, epoxy (meth) acrylate and polyester (meth) acrylate, B component: styrene, (meth) acrylonitrile And a polymer of at least one monomer selected from the group consisting of (meth) acrylic acid esters and having a number average molecular weight of 500 or more, from 5 to 70% by weight. Further, the refractive index at 25 ° C. after curing is 1.520 to
1.560 The adhesive for a cathode ray tube is provided. In addition, the present invention provides a cured product of the adhesive for a cathode ray tube. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Component A The component A used in the adhesive for a cathode ray tube according to the present invention is at least one or more of urethane (meth) acrylate, epoxy (meth) acrylate and polyester (meth) acrylate. It is.

As the urethane (meth) acrylate as the component A, an organic isocyanate (U1 component) is reacted with a (meth) acrylate monomer (U2 component) having at least one hydroxyl group in one molecule by a known method. The reaction product obtained by the reaction can be exemplified. Further, a polyol (U) in which a part of the U2 component has two or more hydroxyl groups in one molecule.
(3 components).

The "organic isocyanate" of the U1 component includes trimer of diisocyanate such as tolylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, methylene bis (4-cyclohexyl isocyanate) and hexamethylene diisocyanate, and isophorone diisocyanate. Examples include isocyanurates such as trimers.

The “(meth) acrylate monomer having at least one hydroxyl group in one molecule” of the U2 component includes 2-hydroxyethyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate.
Examples thereof include hydroxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, phenoxyhydroxypropyl (meth) acrylate, and pentaerythritol tri (meth) acrylate.

The "polyol having two or more hydroxyl groups in one molecule" of the U3 component includes polyether polyols such as polyethylene glycol, polypropylene glycol and polytetraethylene glycol, and polyester polyols such as polycaprolactone and polybutyrolactone. Can be exemplified.

The reaction of the U1 and U2 components is carried out, for example, at a reaction temperature of 60 to 90 ° C. under normal pressure, with the hydroxyl group being 0.8 to 1.2 chemical equivalents per 1.0 chemical equivalent of the NCO group as the U1 component. Particularly preferably, the U2 component is reacted at a ratio of 0.9 to 1.1 chemical equivalent. As the compound having a hydroxyl group, a part of the U2 component may be reacted instead of the U3 component. Generally, it is preferred to use a catalyst to promote the reaction. Catalysts that can be used include dibutyltin dilaurate, dibutyltin diethylhexoate, dibutyltin sulfide, dibutyltin dibutoxide and the like. The amount of the catalyst used is 50 to 5000 ppm, especially 250 to 1 ppm.
It is preferably 000 ppm. This is because a sufficient catalytic action is exhibited in this range.

The epoxy (meth) acrylate which is the component A includes various epoxy resins having at least one epoxy group in one molecule (component E1) and at least a functional group having reactivity with an epoxy group in one molecule. A reaction product obtained by reacting one (meth) acrylate (E2 component) with a known method can be exemplified.

Examples of the E1 component “various epoxy resins having at least one epoxy group in one molecule” include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, alicyclic epoxy resin and the like. And the like.

As the “(meth) acrylate having at least one functional group reactive with an epoxy group in one molecule” of the component E2, acrylic acid, methacrylic acid, (β
-Carboxy-β-methyl) ethyl methacrylate,
Examples thereof include β-carboxyethyl acrylate, crotonic acid, itaconic acid, and fumaric acid.

The reaction between the E1 and E2 components is as follows:
At a reaction temperature of 70 to 130 ° C., the epoxy group 1 of the E2 component
When the functional group is a carboxyl group, for example, the carboxyl group may be added to 0.8 to 1.
The reaction is preferably performed at a mixing ratio of 2 chemical equivalents, particularly 0.9 to 1.1 chemical equivalents. Generally, it is preferred to use a catalyst to promote the reaction. Representative examples of the catalyst include benzylmethylamine, triethylamine, benzyltrimethylammonium chloride, triethanolamine, and the like, and its use amount is 0.1 to 10% by weight, particularly 0.3 to 5% by weight. Is preferred.

The polyester (meth) acrylate as the component A is a polyol having at least two hydroxyl groups in one molecule (component P1), an organic acid having at least two carboxyl groups in one molecule, or the like. Acid anhydride (P2 component) (meth) acrylate having at least one carboxyl group in one molecule (P3
Component) can be exemplified by a reaction product obtained by reacting the same with a known method.

Examples of the "polyol having at least two hydroxyl groups in one molecule" of the P1 component include polyether polyols such as polyethylene glycol, polypropylene glycol and polytetraethylene glycol, and polyester polyols such as polycaprolactone and polybutyrolactone. Can be exemplified.

The "organic acid having at least two carboxyl groups per molecule or an acid anhydride similar thereto" of the P2 component includes phthalic acid, adipic acid, phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, and the like. Examples thereof include acids, isophthalic acid, terephthalic acid, and the like.

Examples of the “(meth) acrylate having at least one carboxyl group in one molecule” of the P3 component include acrylic acid, methacrylic acid, β-carboxy (meth) acrylate, crotonic acid, itaconic acid, fumaric acid and the like. Can be exemplified.

The reaction of the P1 and P2 components is carried out at 70 to 200 ° C. under normal pressure or reduced pressure at a carboxyl group of the P2 component of 0.8 to 1 chemical equivalent of the hydroxyl group of the P1 component.
The reaction is preferably performed at a compounding ratio of 1.2 chemical equivalents, particularly 0.9 to 1.1 chemical equivalents. Generally, it is preferred to use a catalyst to promote the reaction. Typical examples of the catalyst include stannous chloride, titanium tetrabutoxide, dibutyltin dilaurate, and the like, and its use amount is preferably 100 to 10000 ppm.

The component A is contained in the adhesive for a cathode ray tube in an amount of 95 to 3%.
0% by weight, particularly 90 to 90% by weight.
Preferably it is 60% by weight. When the content ratio of the component A exceeds 95% by weight, the shrinkage ratio at the time of curing by the active energy ray is large, causing distortion on the surface of the bonded plastic film sheet, or forming fine gaps at the interface with the panel glass. As a result, there is a problem that the image becomes difficult to see or scratches. On the other hand, when the content ratio of the component A is less than 30% by weight, the viscosity of the composition is remarkably increased, and the coating becomes difficult, which is not suitable for practical use.

Component B The component B used in the adhesive for a cathode ray tube of the present invention is a number average molecular weight obtained by polymerizing a monomer containing at least one of styrene, (meth) acrylonitrile, and (meth) acrylate. It is a polymer of 500 or more.

The monomers constituting the polymer of the component B include:
Styrene, (meth) acrylonitrile, methyl (meth)
Acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, phenoxy (meth) acrylate, morpholine (meth) Examples thereof include acrylate, (anhydride) maleic acid, (anhydride) itaconic acid, and the like.

The component B used in the present invention is a reaction product obtained by reacting the above monomer by a known method. For example, a monomer as a raw material is charged and polymerized in a solvent such as toluene or ethyl acetate at a reaction temperature of 60 to 100 ° C. under normal pressure. In general, the reaction preferably uses a catalyst. Examples of the catalyst include peroxides such as benzoyl peroxide, isobutyl peroxide, and methylbenzoyl peroxide;
An azo compound such as 2-azobisisobutyronitrile and 2,2-azobis (2-methylbutyronitrile) can be exemplified, and its use amount is 0.5 to 10% by weight, particularly 3% by weight.
It is preferably about 8% by weight. After completion of the polymerization, the polymer dope produced is heated by a hot air drier to remove the solvent component by evaporation. The molecular terminal or the side chain portion of the obtained polymer has a hydroxyl group, a (meth) acryloyl group, an allyl group,
Those modified with a polymerizable group such as a styryl group, a vinylbenzyl group, a vinyl ether group, a vinylsilyl group, a dicyclopentadienyl group, an isopropylphenyl group, and a 5-novonen-2-yl group may be used.

The number average molecular weight of the B component is preferably 500 or more, and more preferably 1,000 to 10,000. If the number average molecular weight is less than 500, the shrinkage during curing is large, which is not suitable for practical use.

The component B is contained in the adhesive for a cathode ray tube in an amount of 5 to 70%.
%, Preferably from 10 to 4% by weight.
It is preferably 0% by weight. The content ratio of the B component is 5
If the content is less than 10% by weight, the shrinkage at the time of curing by active energy rays is large, causing distortion on the surface of the laminated plastic film sheet or forming a fine gap at the interface with the panel glass, resulting in an image. However, it causes inconvenience that it becomes difficult to see and that it looks scratched. On the other hand, when the content ratio of the component B exceeds 70% by weight, the viscosity of the composition is remarkably increased, so that the coating becomes difficult and is not suitable for practical use.

In the present invention, any ethylenically unsaturated monomer (hereinafter, referred to as a diluent monomer) may be used for the purpose of adjusting the viscosity of the adhesive for a cathode ray tube, improving the physical properties of a cured product, and the like. It is possible. As the diluting monomer, styrene, (meth) acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate,
Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobonyl (meth) acrylate,
Cyclohexyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 1,4-butanediol (meth) acrylate, phenoxyhydroxypropyl (meth) acrylate, Trimethylolpropane (meth) acrylate,
Pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 2-
Examples thereof include chlorostyrene and (meth) acrylic acid. These diluent monomers may be used alone or in combination of two or more. The amount of the diluting monomer
5 to 7 parts by weight per 100 parts by weight of the adhesive for a cathode ray tube of the present invention.
It is preferably 0 parts by weight, particularly preferably 10 to 40 parts by weight. This is because the viscosity can be sufficiently adjusted in this range.

The adhesive for a cathode ray tube of the present invention can be cured by active energy rays such as ultraviolet rays and electron beams. In the case of curing by ultraviolet rays, a photopolymerization initiator may be previously mixed with the adhesive for a cathode ray tube. Further, if necessary, a photopolymerization initiation auxiliary agent can be used in combination. The photopolymerization initiator is not particularly limited, but typical examples thereof include benzoin, benzophenone, benzoin methyl ether, benzyldimethyl ketal, and 2-hydroxy-2-methyl-1-phenylpropan-1-one. it can. The photopolymerization initiation aid is not particularly limited, but typical examples thereof include amines such as triethanolamine, methyldiethanolamine, and ethyl 4-dimethylaminobenzoate.

Furthermore, the adhesive for a cathode ray tube of the present invention can sufficiently achieve its purpose with the above-mentioned components, but furthermore, in order to improve the performance and physical properties, the adhesive is used as long as the original characteristics are not changed. A foaming agent, a leveling agent, an antistatic agent, an antioxidant, a light stabilizer, an ultraviolet absorber and the like can also be added.

The adhesive for a cathode ray tube of the present invention comprises a cured product 2
The refractive index at 5 ° C. is preferably from 1.520 to 1.560, particularly preferably from 1.530 to 1.540. Generally, the refractive index of a panel glass used for a cathode ray tube is 1.
When the refractive index of the adhesive for a cathode ray tube deviates from the above range, the difference in the refractive index becomes too large, and scratches on the screen become noticeable. The refractive index of the cured product of the adhesive for a cathode ray tube can be adjusted by using a component having a high or low refractive index in an appropriate mixing ratio among the components constituting the adhesive for a cathode ray tube. For example, in order to increase the refractive index of the cured product, a high refractive index component, for example, to use a lot of components having a large number of aromatic rings such as polystyrene, and conversely, when reducing the refractive index of the cured product, A low refractive index component, for example, a polyacrylic acid ester is frequently used.

Using the adhesive for a cathode ray tube of the present invention, a cathode ray tube for a television and various CRT displays can be manufactured. For example, by applying the cathode ray tube adhesive of the present invention to a CRT panel glass before being polished and formed of molten glass, and then laminating a film sheet on the coated surface, the polishing process of the panel glass is streamlined, and various cathode ray tubes Can be manufactured.

[0032]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

(Measurement Items) (1) Viscosity (cP / 25 ° C.): Measured using an E-type viscometer. (2) Refractive index: The refractive index of the resin composition before curing and the cured product cured by ultraviolet irradiation under the conditions of (3) were measured at 25 ° C. using an Appe refractometer. (3) UV curability: An adhesive for each cathode ray tube is coated on a glass plate to a thickness of 200 μm, and a high-pressure mercury lamp of 120 W
/ Cm × 8 m / min. Irradiation with ultraviolet light in x1 pass was performed to determine whether the adhesive was cured or not by finger touch. as a result,
な し indicates no tack on the surface of the adhesive coating, Δ indicates slight tack on the surface of the adhesive coating, and × indicates tack on the surface of the adhesive coating. (4) Curing shrinkage ratio: before curing of the cathode ray tube adhesive and (3)
The specific gravity of each of the cured products cured under the conditions described above is measured, and the following formula is obtained from the following formula: curing shrinkage (%) = ｛[(specific gravity after curing) − (specific gravity before curing)] / (before curing) Specific gravity) x 1
At 00, the cure shrinkage was determined. (5) Adhesiveness: 200 μm of each adhesive on panel glass
After applying a polyester film (manufactured by Teijin Limited, with a primer treatment on the surface) so as not to form a gap, ultraviolet light with an integrated light amount of 400 mJ / cm ^{2 is applied by} a high-pressure mercury lamp. And cured. Cut this polyester film with 2cm width, 90 °
The adhesive strength was measured by peeling off.

[Synthesis Example 1] A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a dry air supply port was immersed in an oil bath, and 2,4-tolylene isocyanate (TDI) was added thereto.
348 g (2 mol) of dibutyltin dilaurate (DB
TDL) was charged and the temperature was raised. When the temperature in the reaction vessel reached 70 ° C., 530 g (1 mol) of polycaprolactone (“PCL205”, molecular weight 530, manufactured by Daicel Chemical Industries, Ltd.) was dropped from the dropping funnel. After the completion of the dropwise addition, when the residual NCO concentration became 4.8% or less of the theoretical value, 232 g (2 mol) of 2-ethylhexyl acrylate was added dropwise from the dropping funnel. After dropping, remaining NC
Aging was performed until the O concentration became 0.1% or less to obtain urethane acrylate.

[Synthesis Example 2] Instead of the TDI of Synthesis Example 1,
4,4-diphenylmethane diisocyanate (MDI)
A urethane acrylate was obtained in the same manner as in Synthesis Example 1 except that the amount was 500 g (2 mol).

[Synthesis Example 3] Instead of 2-ethylhexyl acrylate in Synthesis Example 1, EO-modified phthalic acrylate (“Biscoat 2308” manufactured by Osaka Organic Chemical Industry Co., Ltd.)
Was used in the same manner as in Synthesis Example 1 except that 618 g (2 mol) of was used to obtain a urethane acrylate.

Examples 1 to 6 and Comparative Examples 1 to 3
The components were uniformly mixed according to the composition shown in Example 1 to obtain an adhesive for a cathode ray tube.

[0038]

[Table 1]

[0039]

The adhesive for a cathode ray tube of the present invention has a refractive index,
Adhesiveness and shrinkage during curing are low, and it is effective as a cathode ray tube adhesive for bonding a panel glass and a plastic film.

Claims (3)

[Claims] 1. An adhesive for a cathode ray tube comprising the following components A and B: A component: 95 to 30% by weight of at least one or more (meth) acrylates selected from the group consisting of urethane (meth) acrylate, epoxy (meth) acrylate and polyester (meth) acrylate, B component: styrene, (meth) acrylonitrile And a polymer of at least one monomer selected from the group consisting of (meth) acrylates and having a number average molecular weight of 500 or more, 5 to 70% by weight 2. A cured product having a refractive index at 25 ° C. of 1.5
The adhesive for a cathode ray tube according to claim 1, wherein the adhesive is 20 to 1.560. 3. A cured product of the adhesive for a cathode ray tube according to claim 1.