JPH07188638A - Adhesive composition containing refractive index modifier and laminate prepared with same - Google Patents

Abstract

PURPOSE:To obtain an adhesive compsn. which has a refractive index easily made equal or close to that of an essentially transparent adherend by adding a specific compd. as the refractive index modifier to a hot-melt urethane adhesive. CONSTITUTION:Pref. a nonhalogenous phosphoric ester. a halogenous phosphoric ester, or an arom. organophosphorus compd. prepd. by the condensation of a halogenous phosphoric ester (e.g. a condensate of phosphoryl chloride, phenol, and resorcin) is added as the refractive index modifier to a hot-melt urethane adhesive [e.g. obtd. by reacting a polyester polyol with methylenebis (cyclohexyl isocyanate) and isophorone diisocyanate and then with 1,4-butanediol].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition containing a refractive index adjusting agent, and an adhesive composition adjusted to have a refractive index equal to or close to that of an essentially transparent adherend. The present invention relates to a laminate having a soft resin film, which is transparent and has self-repairing properties and scratch resistance, adhered thereto, and particularly to an unpolished or rough-polished glass panel such as a cathode ray tube.

[0002]

2. Description of the Related Art Conventionally, cathode ray tube glass panels used in televisions and the like are produced by press-molding molten lumps of glass, but distortions and scratches on the panel surface that occur during molding are removed by several polishing processes. Get burned. Distortions and scratches on the panel surface are caused by contact between the cut end and the mold during glass measurement, the following condition of the glass during pressing, dust and human act. It is difficult to completely avoid these causes, and currently polishing is performed according to the type of scratch. Therefore, it is necessary to select a curved surface that is easy to polish as the shape of the glass panel.

On the other hand, in recent years, flattening of glass panels has been promoted from the viewpoint of the design of cathode ray tubes and the improvement of image quality. However, flattened glass panels are difficult to polish, and the strain and scratches on the panel surface cannot be removed by polishing. On the other hand, there is a strong demand for simplifying the polishing process in order to reduce costs.

Therefore, a polyethylene terephthalate film is laminated on an unpolished glass panel via a urethane acrylate UV-curing adhesive having the same or a similar refractive index as the glass, and the glass panel is cured by UV irradiation. It was proposed to manufacture. It is known that this glass panel exhibits the same performance as a polished glass panel to the extent that distortion and scratches cannot be visually confirmed.

However, the surface of the above glass panel is polyethylene terephthalate, so that it has a problem in scratch resistance. Therefore, the present inventors have proposed to laminate a transparent, self-healing, scratch-resistant polyurethane film on the polyethylene terephthalate layer. (Japanese Patent Application No. 5-140070)

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to an adhesive composition which is used for forming the above-mentioned laminated body and the like and whose refractive index can be easily adjusted, and a laminated body which is laminated using the adhesive composition. Is to provide.

[0007]

The present invention provides (1) an adhesive composition characterized in that an aromatic organic phosphorus compound is added to a urethane hot melt adhesive as a refractive index adjusting agent,
And (2) transparent and self-healing with respect to a transparent adherend, through the above urethane-based hot melt adhesive composition adjusted to have a refractive index equal to or close to that of the adherend. And a soft resin film having scratch resistance and scratch resistance is adhered. By the way, in order to give the adhesive layer a refractive index equivalent to or close to that of a transparent adherend, there is a difference between the refractive index of the urethane hot melt adhesive layer with no refractive index adjustment and the refractive index of the adherend. It is necessary to increase the addition amount of the refractive index adjusting agent to some extent. But,
If the amount of addition is increased, the softening temperature becomes too low, workability deteriorates, and tacking is likely to occur due to bleed-out of the additive, resulting in problems such as deterioration in adhesiveness. Therefore, in order to reduce the added amount, it is desirable that the refractive index of the refractive index adjusting agent is high.

Therefore, in the present invention, in order to adjust the refractive index of the adhesive composition, an aromatic organophosphorus compound having excellent compatibility with the urethane hot melt adhesive is selected. Specifically, as the aromatic organophosphorus compound, a non-halogen phosphate ester, a halogen-containing phosphate ester or a condensate thereof can be used, and in particular, the molecular weight is 50 or less.
It is desirable to use a condensate of phosphoryl chloride with phenol and resorcinol in the range 0 to 10,000, preferably in the range 500 to 2000. When the molecular weight is less than 500, there is a defect that the film becomes soft and bleed out easily, and when it exceeds 2000, it becomes a viscous liquid and the operability deteriorates, so it is preferable to use in the above range. .

The above-mentioned refractive index adjusting agent has a refractive index of the urethane hot-melt adhesive layer whose refractive index is not adjusted and a refractive index of the adherend so as to have a refractive index equal to or close to that of the transparent adherend. The value estimated from can be added. Generally, the glass panel for cathode ray tubes has a refractive index in the range of 1.54 to 1.60, and the urethane-based hot-melt adhesive with no refractive index adjustment has a refractive index in the range of 1.49 to 1.54.
The refractive index of the urethane hot-melt adhesive composition may be adjusted within the range of ± 0.01 with respect to the adherend by adding the above-mentioned aromatic organophosphorus compound in the range of 1.50 to 1.65.

As for the method of addition, it may be added from the beginning during the synthesis of urethane, or may be added at an intermediate stage. Furthermore, they can be mixed after the urethane synthesis, and the urethane compound may be added after being dissolved in a soluble solvent. The refractive index adjusting agent may be a mixture of two or more kinds.

The adhesive used in the present invention is disclosed in Japanese Patent Application No. 61-
The urethane hot melt adhesives described in No. 64942, especially the non-yellowing thermoplastic urethane adhesives are suitable. The yellow-free modified polyurethane-based resin refers to a polyurethane-based resin obtained from a polyisocyanate having no isocyanate group directly bonded to an aromatic nucleus as a raw material.

This urethane hot melt adhesive is
(a) Polyoxyalkylene diol, polyester diol as a main component molecular weight 500 ~ 3000, preferably
600-2000 polyol, (b) divalent isocyanate, and (c) bifunctional chain extender as main raw materials, urethane hard content [(b + c) / (a + b + c) weight ratio] To 0.15 to 0.5, preferably 0.2 to 0.45, and (a) a high molecular weight diol and (c) 2
The total number of functional groups of the functional chain extender is 100, and the divalent isocyanate compound (b) has an isocyanate group number of 93 to
Molecular weight obtained by reacting at a ratio of 99.8 25,000-8
The main component is a substantially linear polyurethane polymer.

(A) As the divalent isocyanate compound,
Aliphatic, alicyclic and other diisocyanate compounds and modified products thereof can be used. A preferred divalent isocyanate compound is hexamethylene diisocyanate,
Examples thereof include isophorone diisocyanate and methylenebis (cyclohexyl isocyanate).

(B) The bifunctional chain extender has a molecular weight of
60-400, preferably 90-200 diols and diamines,
A diol that is particularly easy to handle is suitable. Further, in order not to reduce the water resistance of the adhesive, it is preferable to use a hydrophobic bifunctional chain extender. Specifically, an aliphatic diol having 4 to 10 carbon atoms, particularly 1,4-butanediol,
1,6-hexanediol, 1,8-octanediol, neopentyl glycol and the like are preferable.

A silane coupling agent may be added to the urethane-based hot melt adhesive composition of the present invention to enhance the adhesiveness.

As the silane coupling agent, a compound represented by the following formula can be used, and it is possible to use a single compound or a combination of two or more compounds.

In the formula of R ⁷ _e SiX ³ _4-e , X ³ is a halogen atom, an alkoxy group, a hydroxyl group, an acyloxy group, a ketoximate group, an amino group, an amido group, an aminooxy group, a mercapto group, an alkenyloxy group or the like. A decomposable group, R ⁷ represents hydrogen, an organic group having 1 to 30 carbon atoms, and e represents an integer of 0 to 3.

X ³ is preferably an alkoxy group from the viewpoint of hydrolyzability and handleability. Particularly, the hydrolyzable group is preferably a methoxy group or an ethoxy group because of its high reactivity, and it is preferable that two or more, and more preferably three or more of these groups are attached to one silicon atom.

Specifically, methyl silicate, ethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, butyltrimethoxysilane, octyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane. Methoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane,
Silane compounds having no functional group such as diethyldiethoxysilane, dibutyldimethoxysilane, diphenyldimethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, triethylmethoxysilane, triethylethoxysilane, triphenylmethoxysilane; trimethoxysilane, dimethoxymethyl Silane compounds such as silane and triethoxysilane; vinylsilanes such as vinyltrimethoxysilane and vinylmethyldimethoxysilane; γ-methacryloxypropyltrimethoxysilane,
(Meth) such as γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane
Acrylic silanes; γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane,
N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, N-β- (N-vinyl Benzylaminoethyl) -γ-aminopropyltrimethoxysilane, γ-anilinopropyltrimethoxysilane and other amino group-containing silanes; γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyl Dimethoxysilane,
γ-Mercaptopropylmethyldiethoxysilane and other mercaptosilanes; γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and γ-glycodoxypropyltriethoxysilane and other epoxysilanes; β -Carboxyethyltriethoxysilane, β-carboxyethylphenylbis (2
-Methoxyethoxy) silane, N-β- (N-carboxylmethylaminoethyl) -γ-aminopropyltrimethoxysilane and other carboxysilanes; γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ- Isocyanate silanes such as isocyanate propyl dimethoxymethyl silane and the like can be mentioned.

The laminate of the present invention can be applied to a transparent adherend such as an unpolished or rough-polished glass panel for a cathode ray tube.
A transparent soft resin film having self-healing property and scratch resistance is bonded through a urethane hot melt adhesive composition adjusted to have a refractive index equal to or close to that of the adherend. is there.

The soft resin film of the present invention includes a polyurethane resin, an acrylic transparent rubber-like resin, a silicone rubber-like resin, an olefin-based or styrene-based elastomer, a mixture thereof, or a mixture with another resin, Although a polymer alloy or the like can be used, a polyurethane resin is most preferable from the viewpoint of the balance of transparency, self-healing property, and scratch resistance.

The soft resin film used in the present invention may be made of only the above-mentioned specific soft synthetic resin, or a layer made of the material may be used as one surface layer. The thickness of this resin film is preferably in the range of 0.1 to 2 mm. This resin film preferably has a visible light transmittance of 50% or more, particularly 80% or more, and when the surface of the film has fine irregularities, the transmittance of the film having it is preferably 50% or more.

The surface of the soft resin layer (the surface to be the touch surface) has fine irregularities called so-called embossing and is effective in preventing reflection, but it is not preferable to set the transmittance to less than 50%. The film may be colored as long as it is essentially transparent, and may be patterned by printing or the like. Also, a thin colored film or a patterned film may be laminated.

The self-healing property of the soft resin film used in the present invention means the property that scratches once generated disappear with time. HEIDON (HEID
ON) There is a method using a scratch tester. 20 ° C, 50
% In a relative humidity atmosphere, a self-healing property measured by a Haydon scratch tester with a diamond tip having a tip diameter of 15 microns as a damaged body is preferably 10 g or more,
Particularly, 30 g or more is preferable.

The scratch resistance of the soft resin film used in the present invention is 10% increase in haze value after 100 rotations in a Daver abrasion test at a load of 500 g using CS-10F as an abrasion wheel in the same atmosphere as described above. It is preferably less than.

As the method for molding the soft resin film, extrusion molding method, injection molding method, blow molding method, casting method,
Although a calendar molding method or the like is possible, the reactive casting method is most suitable from the viewpoint of the optical quality of the film, which is particularly related to image distortion, and the fact that a crosslinkable resin can also be molded.

[0027]

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

(Example 1) 100 parts by weight of a polyester polyol having a hydroxyl value of 55.4 (Kuraray Clarpol P-2010), 60 ppm of dibutyltin dilaurate based on the finished product, and 0.3% of Tinuvin 328 (Ciba Geigy UV absorber) ), 0.2% Irganox 1010 (antioxidant manufactured by Ciba Geigy), and 0.2% Mark LA-7H (light stabilizer manufactured by Asahi Denka Co., Ltd.) were added and dissolved by stirring at 80 ° C. 68.70 parts by weight of methylenebis (cyclohexyl) isocyanate and 103.05 parts by weight of isophorone diisocyanate were added thereto and reacted at 80 ° C. for 15 minutes.

Next, 61.59 parts by weight of 1,4-butanediol was added and mixed with stirring. After the reaction started to generate heat and became essentially uniform, it was put in a stainless steel vat covered with PTFE and cured in a hot air circulation oven at 120 ° C for 15 hours to synthesize urethane. The refractive index of the obtained compound was 1.50.

This compound was dissolved in a mixed solution of methyl ethyl ketone / 1,4-dioxane to obtain a uniform solution, and 70 parts by weight of tricresyl phosphate having a refractive index of nD1.557 was added to urethane to obtain a refractive index. A urethane hot melt adhesive solution adjusted to nD1.54 was obtained.

Next, the obtained adhesive solution was treated with a refractive index nD1.54.
After coating and drying on an unpolished tube panel, a film having a soft resin layer on the surface was laminated, heated at 80 ° C. and bonded with a nipper roller, and scratches on the panel surface could not be visually confirmed. .

(Example 2) Instead of the tricresyl phosphate of Example 1, a condensate of phosphoryl chloride having a refractive index of nD1.5750 and a molecular weight of 600, phenol and resorcinol (trade name: CR-733S, Daihachi Chemical Industry Co., Ltd.). The soft resin layer was bonded in the same manner, except that 53 parts by weight of the product) was added. The scratches on the panel surface could not be visually confirmed.

(Example 3) Instead of the tricresyl phosphate of Example 1, a condensate of phosphoryl chloride having a refractive index of nD1.5786 and a molecular weight of 1000 and phenol and resorcinol (trade name: CR-735 Daihachi Chemical Industry Co., Ltd. The soft resin layer was bonded in the same manner, except that 49 parts by weight of the product) was added. The scratches on the panel surface could not be visually confirmed.

(Comparative Example 1) A soft resin layer was formed on an unpolished tube panel in the same manner as in Example 1 except that an adhesive solution in which tricresyl phosphate as a refractive index adjusting agent was omitted was used. When laminated, scratches on the panel surface were visually confirmed.

(Comparative Example 2) A soft resin was applied to an unpolished tube panel in the same manner as in Example 1 except that the amount of tricresyl phosphate added in Example 1 was reduced to adjust the refractive index to nD1.52. When the layers were laminated, some scratches on the surface of the panel were visually confirmed.

[0036]

EFFECTS OF THE INVENTION The present invention makes it possible to provide an adhesive composition whose refractive index can be adjusted in a relatively wide range by adopting the above-mentioned constitution, and to polish a glass panel such as a cathode ray tube. By making it possible to directly bond the urethane-based hot melt adhesive layer whose refractive index is adjusted to the glass panel of the cathode ray tube, it is possible to easily flatten and reduce the weight of the glass panel.

Claims (7)

[Claims] 1. An adhesive composition in which an aromatic organic phosphorus compound is added to a urethane hot melt adhesive as a refractive index adjusting agent. 2. The adhesive composition according to claim 1, wherein the aromatic organophosphorus compound is a non-halogen phosphate ester, a halogen-containing phosphate ester or a condensate thereof. 3. The adhesive composition according to claim 2, wherein the aromatic organophosphorus compound is a condensate of phosphoryl chloride, phenol and resorcinol, and its molecular weight is in the range of 500 to 10,000. 4. The urethane hot melt adhesive is a non-yellowing thermoplastic urethane.
The adhesive composition according to any one of 3 to 3. 5. The adhesive composition according to claim 1, wherein the urethane hot melt adhesive composition contains a silane coupling agent as an additive. 6. The urethane hot melt adhesive according to claim 1, wherein the transparent adherend is adjusted to have a refractive index equal to or close to that of the adherend. A laminate comprising a transparent, self-healing and scratch-resistant soft resin film adhered via the composition. 7. The laminate according to claim 6, wherein the adherend is an unpolished or rough-polished glass panel.