JP3017087B2 - CRT explosion-proof adhesive tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for preventing implosion of a cathode ray tube used in a television or the like.
The present invention relates to a CRT explosion-proof adhesive tape.

[0002]

2. Description of the Related Art A cathode ray tube used in a television or the like is subjected to a force due to the atmospheric pressure because the inside thereof is extremely evacuated, so that a tensile stress is generated from the periphery of the cathode ray tube to a side wall. Glass is vulnerable to tensile stress, and if there are minute scratches on the surface, it grows due to tensile stress and cracks to cause breakage and implosion. In order to prevent this implosion, explosion-proof treatment is performed by tightly tightening the vicinity of the maximum outer diameter portion of the cathode ray tube with a metal band. This metal band may damage the glass surface when it comes in direct contact with the glass cathode ray tube, and the band may slip due to the curved surface of the cathode ray tube when the band is tightened, and the tightening reinforcement effect may not be achieved. is there.

In order to avoid such disadvantages caused by direct contact between the metal band and the glass cathode ray tube, an explosion-proof adhesive tape is interposed between the metal band and the cathode ray tube. Adhesive tape prevents cracking when a CRT is impacted. As a method of tightening the band, a metal band smaller than the outer diameter of the cathode-ray tube is used in advance to about 400 to 65.
A so-called shrink fit method, in which the material is heated to 0 ° C., expanded, and fitted into a cathode ray tube, is generally used. When the band cools, it contracts and applies pressure to the cathode ray tube side wall,
Relieves tensile stress.

Examples of the pressure-sensitive adhesive tape for explosion-proof cathode ray tubes used for the above purpose include an adhesive tape using a glass cloth on a tape base as described in Japanese Patent Publication No. 63-24291, and Japanese Patent Application No. Hei. The mainstream is to use an adhesive tape using a cross-woven cloth as a tape base as described in JP-A-132422. These tapes
Although there is no major problem in terms of function, it is disadvantageous in that it is expensive, and in recent years, with the spread of OA equipment such as televisions, demands for cost reduction have increased. Therefore, in some cases, an adhesive tape based on an inexpensive polyethylene terephthalate film is used as an adhesive tape for CRT explosion-proof, but the melting point (about 260 ° C.) of the polyethylene terephthalate film has an explosion-proof treatment temperature (about 400 to 400 ° C.).
(600 ° C.), it melts during explosion-proof treatment. When the adhesive tape melts, there is a step or protrusion called the mold match line on the outer circumference of the cathode ray tube, so the tape melted at the time of processing starts flowing at the band, especially at the corner with a large pressing force, As a result, the band and the cathode ray tube often come into direct contact with each other, which is unreliable as an explosion-proof tape.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an explosion-proof tape for preventing CRT implosion by sticking an adhesive tape around a mold match line near the maximum outer diameter of a CRT with an adhesive surface. An inexpensive and highly functional CRT explosion-proof adhesive tape is used to tighten the heated metal band on the surface of the hot-melt adhesive layer to prevent the implosion of the CRT and the band. It is intended to provide.

[0006] In particular, the present invention relates to the use of polyethylene terephthalate, high-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer as the base material of the adhesive tape for CRT explosion-proof Using a film or sheet consisting of a single or multilayer thermoplastic film or sheet of ethylene / vinyl acetate copolymer, polypropylene, etc. It is an object of the present invention to provide a pressure-sensitive adhesive tape for explosion-proof cathode-ray tubes that does not melt even at a temperature.

[0007]

The present invention for solving the above-mentioned problems relates to a pressure-sensitive adhesive tape for explosion-proof cathode-ray tubes , wherein a heat-absorbing substance is contained in a substrate and / or a pressure-sensitive adhesive layer. . Also, the present invention provides the heat-absorbing substance,
The present invention relates to the above-mentioned pressure-sensitive adhesive tape for explosion-proof cathode-ray tubes, which is made of a substance that changes its endotherm under explosion-proof treatment temperature conditions.

The present invention relates to the above-mentioned pressure-sensitive adhesive tape for CRT explosion, wherein the endothermic substance is a hydrate and / or a hydroxide. The present invention also relates to the pressure-sensitive adhesive tape for CRT explosion described in any of the above, wherein the endothermic substance is a hydrate and / or a metal hydroxide of a metal compound.

According to the present invention, the endothermic substance is Al (O
H) ₃ , Mg (OH) ₂ , Ca (OH) ₂ , Al ₂ O _{3
· H 2 O, Na · Al} · O (OH) · HCO 3, Mg 6
Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O, 3CaO.Al
_{2 O 3 · 6H 2 O,} CaSO 4 · 2H 2 O, ZnO · 2
_{B 2 O 3 · 3.5H 2 O} , BaO · B 2 O 3 · H 2 O,
Na ₂ O · ₂ B ₂ O ₃ · 10H ₂ O, Al ₂ O ₃ · Si
O 2 _· the CRT explosion-proof pressure-sensitive adhesive tape according to any one of, wherein the 2H of at least one selected from 2 _O related.

In the present invention, the base material is preferably polyethylene terephthalate, high density polyethylene, low density polyethylene, ultra low density polyethylene, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl acetate copolymer. The explosion-proof pressure-sensitive adhesive tape according to any one of the above, wherein the pressure-sensitive adhesive tape is formed of a single body or a multi-layer body of a thermoplastic resin film or sheet such as coalesced or polypropylene. The present invention also relates to the pressure-sensitive adhesive tape for CRT explosion-proof according to any one of the above, wherein the endothermic substance is contained in a substrate. The present invention also relates to the pressure-sensitive adhesive tape for CRT explosion-proof according to any of the above, wherein the heat-absorbing substance is contained in an adhesive. Furthermore, the present invention relates to the pressure-sensitive adhesive tape for CRT explosion-proof according to any of the above, wherein the endothermic substance is contained in both the base material and the pressure-sensitive adhesive.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the pressure-sensitive adhesive tape for CRT explosion-proof according to the present invention, the base material is polyethylene terephthalate, high-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate A base material is used which is made of a single or multi-layered thermoplastic resin film or sheet such as a copolymer, an ethylene / vinyl acetate copolymer, or polypropylene. The thickness of the substrate is selected in the range of 25-300μ. If it is less than 25 μ, no effect can be expected even as a buffer material, and if it exceeds 300 μ, the difference between the outer peripheral length of the cathode ray tube and the inner peripheral length of the tightening band becomes large, and the tightening force after cooling becomes insufficient.

[0012] In the pressure-sensitive adhesive tape for CRT explosion-proof of the present invention, the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer provided on the substrate surface may be a natural rubber, a synthetic rubber, an acrylic,
Various adhesives such as silicone adhesives can be used, but natural rubber adhesives and acrylic adhesives are usually used. The thickness of the pressure-sensitive adhesive layer is 10 μ to 200 μ. If it is less than 10 μm, sufficient adhesive strength cannot be obtained, and if it exceeds 200 μm, the fluidity of the adhesive increases due to shrink-fitting treatment, and a slip phenomenon occurs in the band, which is not preferable.

In the pressure-sensitive adhesive tape for explosion-proof cathode ray tubes of the present invention, the heat-absorbing substance to be contained in the substrate and / or the pressure-sensitive adhesive layer may be a heat-absorbing substance at a temperature of about 400 to 600 ° C., which is the processing temperature in the explosion-proof processing step. It is used to decompose to remove surrounding heat, suppress the melting of the base material and the flow of the adhesive, form a continuous buffer layer, and prevent the band from directly contacting the cathode ray tube. For example, aluminum hydroxide [Al (OH) ₃ , Mg (OH) ₂ ], calcium hydroxide [Ca (OH) ₂ ], hydrated alumina [Al
₂ O ₃ .H ₂ O], dawsonite [Na.Al. (O
H) .HCO ₃ , hydrotalcite [Mg ₆ Al
₂ (OH) ₁₆ CO ₂ .4H ₂ O], calcium aluminate [3CaO.Al ₂ O ₃ .6H ₂ O], gypsum [CaSO ₄ .2H ₂ O], zinc borate [ZnO
.B ₂ O ₃ .3.5H ₂ O], barium metaborate [B
aO.B ₂ O ₃ .H ₂ O], Borax [Na ₂ O.2B ₂
O ₃ .10H ₂ O], kaolin clay [Al ₂ O ₃ .S
iO ₂ · 2H ₂ O] is at least one selected from such use.

The amount of the endothermic substance to be added can be appropriately set in the range of 10 to 80% by weight based on the weight of the entire tape. When the heat-absorbing substance is added to the tape base material, the amount must be such that the tensile strength required for the pressure-sensitive adhesive tape, for example, the tensile strength necessary for winding the tape around a cathode ray tube at a high speed, is not impaired. If an endothermic substance is added to the substrate, the effect of immediately lowering the temperature can be obtained because the heating band is in direct contact with the substrate during shrink fitting.

When it is difficult to directly add an endothermic substance to a substrate such as a polyethylene terephthalate film, the same effect can be obtained by adding the substance to a pressure-sensitive adhesive layer. When it is added to the pressure-sensitive adhesive layer, it must be in an amount that does not impair the adhesive strength required for winding and fixing to the cathode ray tube. Usually, when adding to the pressure-sensitive adhesive layer, it is preferable to divide the pressure-sensitive adhesive layer into two layers, to include a heat-absorbing substance in a layer in contact with the base material, and to separately provide a pressure-sensitive adhesive layer thereon. By thus forming the pressure-sensitive adhesive layer into a two-layer structure, the heat-absorbing substance can be added to the pressure-sensitive adhesive layer without lowering the adhesive strength of the tape, and the tape base can be efficiently prevented from melting. Can be demonstrated.

The endothermic substance is usually added as a powder to the tape substrate or the pressure-sensitive adhesive layer. The particle size of the powder of the endothermic substance is not particularly limited, but is appropriately selected usually in the range of 0.5 μm to 100 μm depending on the thickness of the base material or the pressure-sensitive adhesive layer.

[0017]

EXAMPLES Hereinafter, the pressure-sensitive adhesive tape for CRT explosion prevention of the present invention will be described in detail with reference to Examples, but the present invention is not limited to those described in these Examples.

Example 1 An acrylic pressure-sensitive adhesive (46 parts of butyl acrylate, 42 parts of 2-ethylhexyl acrylate, 7 parts of vinyl acetate, 5 parts of acrylic acid, weight average molecular weight of 600,000) was 20% by weight and aluminum hydroxide (Showa) The endothermic layer composed of 80% by weight of Heikolite H-10) manufactured by Denko K.K.
A 125 μm thick polyethylene terephthalate film (manufactured by Toray, Lumirror S-10, hereinafter referred to as a PET film) is coated on one side, and a 40 μm thick acrylic pressure-sensitive adhesive layer (same as the acrylic pressure-sensitive adhesive) is further provided thereunder. A pressure-sensitive adhesive tape for CRT explosion-proof having a total thickness of 0.265 mm was produced (see FIG. 1).

Comparative Example 1 An acrylic pressure-sensitive adhesive layer (same as the lower layer in Example 1) was applied to one side of a PET film having a thickness of 125 μm (same as Example 1) so as to have a thickness of 40 μm. 0.16 thickness
A 5 mm tape was produced (see FIG. 2).

Example 2 Magnesium hydroxide (Kisuma 5B, manufactured by Kyowa Chemical Industry Co., Ltd.) was converted to a polyethylene resin (Exelen VL1, manufactured by Sumitomo Chemical Co., Ltd.).
00), a corona discharge treatment was performed on one surface of a polyethylene film having a thickness of 100 μm, and a 50 μm synthetic rubber-based pressure-sensitive adhesive layer (100 parts of styrene-butadiene rubber, 100 parts of natural rubber, 50 parts of C ₅ petroleum resins, _{C 9} type to form a petroleum resin 40 parts), to prepare a cathode ray tube explosion-proof adhesive tape the entire thickness of the 0.150 mm (see Figure 3).

Comparative Example 2 A synthetic rubber-based pressure-sensitive adhesive layer having the same thickness as in Example 2 (same as in Example 2) was formed on one side of a 100 μm-thick polyethylene film (Sumikasen F208, manufactured by Sumitomo Chemical Co., Ltd.). , CRT protection with a total thickness of 0.150mm
An explosive adhesive tape was produced (see FIG. 4).

Example 3 A polyethylene resin (same as Example 2) containing 50% by weight of magnesium hydroxide (same as Example 2) having a thickness of 2
A polyethylene laminate layer having a thickness of 60 μ was formed on a 5 μ PET film (Lumirror S-10, manufactured by Toray Industries, Inc.).
An acrylic pressure-sensitive adhesive layer having the thickness of 40 μm (same as the lower pressure-sensitive adhesive layer of Example 1) was formed on the ET film surface, and a CRT explosion-proof pressure-sensitive adhesive tape having a total thickness of 0.125 mm was produced (FIG. -5).

Comparative Example 3 A 60 μm thick polyethylene resin (same as Example 3) laminate layer was formed on a 25 μm thick PET film (same as Example 2), and a 40 μm thick acrylic resin was formed on the PET film surface. An adhesive layer (same as in Example 3) was formed, and an adhesive tape for CRT explosion-proof having an overall thickness of 0.125 mm was produced (see FIG. 6).

Example 4 A polyethylene resin (same as in Example 3) containing 40% by weight of magnesium hydroxide (same as in Example 2) was laminated on a regenerated fiber woven fabric having a thickness of about 200 μm, and the thickness was reduced. 24
On the woven fabric surface of the base material having a thickness of 0 μm (the thickness of the laminate layer itself is 60 μm, but because the woven fabric is hardly embedded, the unlaminated laminate layer is 40 μm and the thickness is 240 μm). Natural rubber adhesive layer (natural rubber 100
Parts, 150 parts of calcium carbonate, _{C 5} petroleum resins 100
Parts, 25 parts of a softening agent, 2 parts of an antioxidant, and 2 parts of a vulcanizing agent) to produce a CRT explosion-proof adhesive tape having a total thickness of 0.310 mm (FIG. 7). reference).

Comparative Example 4 A woven fabric surface of a base material having a thickness of 240 μm was formed by laminating a polyethylene resin (same as Example 4) on a natural fiber interwoven cloth (same as Example 4) having a thickness of about 200 μm. Then, a natural rubber-based pressure-sensitive adhesive layer (same as in Example 4) having a thickness of 70 μm was formed, and a pressure-sensitive adhesive tape for CRT explosion-proof having a total thickness of 0.310 mm was produced (see FIG. 8).

Example 5 A polyethylene resin (same as in Example 4) containing 40% by weight of magnesium hydroxide (same as in Example 4) was laminated on a recycled fiber woven fabric having a thickness of about 200 μm, and the thickness was changed to 240.
70 μm on the woven fabric surface of the base material (same as in Example 4)
Natural rubber adhesive that magnesium hydroxide was compounded 55% by weight of the (natural rubber 100 parts, 150 parts of magnesium hydroxide (the same as Example 4), 100 parts of _{C 5} petroleum resins, _{C 9}
100 parts petroleum resin, 25 parts of softener, 2 parts of antioxidant,
Vulcanizer 2 parts) were formed to prepare a pressure-sensitive adhesive tape for CRT proof that the entire thickness of the 0.310 mm (see Figure 9).

Comparative Example 5 Same as Comparative Example 4 (see FIG. 8).

[Endothermic test] Heat-resistant glass plate (size: 3 mm x 50 mm x 70 mm)
A thermocouple (allomel / chromel, diameter 0.02 mm) was set between the sample tape (size: 20 mm × 70 mm) and an iron plate (size: 1 mm × 15 mm × 100 mm) heated to 550 ° C. assuming explosion-proof treatment. ) Is placed on the tape, immediately pressurized under the condition of 1 kg / cm ² , and allowed to cool to room temperature. The temperature recorder records the temperature every 5 seconds from heating to normal temperature. FIG. 10 shows the results of measuring the temperature change of Comparative Example 1 and Example 1 by the above evaluation method.
Shown in

[State of Tape After Explosion-Proof Treatment] After winding each of the tapes of Examples 1 to 5 and Comparative Examples 1 to 5 around the outer circumference of a 29-inch cathode ray tube one round, the tape has an outer peripheral length of 96 mm. A steel fastening band having a 53 mm width, which is an inner peripheral length of 50%, was heated to about 450 ° C., fitted therein, cooled rapidly, and fastened to obtain a test specimen. Table 1 shows the maximum temperature in the endothermic tests of Examples 1 to 5 and Comparative Examples 1 to 5, and the state of the tape when the band was removed from the test piece.

[0030]

[Table 1]

Note: The evaluation of the condition of the tape after the explosion-proof treatment in Table 1 is good for a tape with a continuous layer formed after the explosion-proof treatment. But some were bad. Long side, corner,
The numerical value on the short side indicates the number of defects in each part, and the numerical value of the number of defects indicates the total number of defects.

[0032]

Effect of the Invention] As explained above, Blau of the present invention
Since the tape has a layer containing an endothermic substance, the endothermic substance in the tape is endothermicly decomposed in the tape and the temperature of the tape rises at high temperatures during the explosion-proof treatment. Explosion-proof treatment of CRTs, which can effectively prevent the tape base material from melting due to the heat of the band and spilling from between the band and the surface of the CRT. Is made possible.

[Brief description of the drawings]

CRT explosion-proof adhesive tape of Example 1 of the present invention
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Comparative Example 1 of the present invention; FIG
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Example 2 of the present invention; FIG
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Comparative Example 2 of the present invention; FIG
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Example 3 of the present invention; FIG
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Comparative Example 3 of the present invention; FIG
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Example 4 of the present invention; FIG
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Comparative Example 4 of the present invention; FIG
The figure which shows the lamination structure of a pump.

CRT explosion-proof adhesive tape of Example 4 of the present invention; FIG
The figure which shows the lamination structure of a pump.

FIG. 10 is a diagram showing a temperature change over time in an endothermic test.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-194915 (JP, A) JP-A-4-363376 (JP, A) JP-A-58-100343 (JP, A) JP-A-60-1985 215088 (JP, A) JP-B 63-24291 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 29/87 C09J ^7/ 00-7/04

Claims (10)

(57) [Claims] 1. A shrink-fitting method characterized in that a heat-absorbing substance is contained in a substrate and / or an adhesive layer comprising a single or multiple layers of a thermoplastic resin film or sheet .
That cathode-ray tube explosion-proof adhesive tape. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the heat-absorbing substance is made of a substance that changes endothermic under an explosion-proof treatment temperature condition. 3. The yaki according to claim 1, wherein the endothermic substance is a hydrate and / or a hydroxide.
Adhesive tape for CRT explosion-proof by fitting method . 4. The endothermic material of claim 1, wherein the hydrates and / or hydroxides of a metal compound
The pressure-sensitive adhesive tape for explosion-proof cathode-ray tubes according to any one of the preceding claims . 5. An endothermic substance comprising A1 (OH) ₃ , Mg
(OH) ₂ , Ca (OH) ₂ , A1 ₂ O ₃ .H ₂ O, N
a · A1 · O (OH) · HCO ₃ , Mg ₆ A1 ₂ (O
_{H) 16 CO 3 · 4H 2} O, 3CaO · A1 2 O 3 · 6H
₂ O, CaSO ₄ .2H ₂ O, ZnO.2B ₂ O _3.
3.5 H ₂ O, claim 1, characterized in that at least one selected from _{A 1 2 O 3 · SiO 2} · 2H 2 O
An explosion-proof adhesive tape for brown pipes according to any one of claims 1 to 4, which is manufactured by a shuffling fit method . 6. The base material is polyethylene terephthalate, high density polyethylene, low density polyethylene, ultra low density polyethylene, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl acetate copolymer, The CRT explosion-proof adhesive according to any one of claims 1 to 5, comprising a thermoplastic resin film or sheet selected from polypropylene alone or a multilayer body thereof. tape. Wherein said pressure-sensitive adhesive layer, according to claim 1 to claim 5, characterized in that it consists of at least one selected from A click Lil-based adhesives, natural rubber-based adhesives and synthetic rubber adhesive A brown tube explosion-proof adhesive tape according to any one of claims 1 to 4. 8. The pressure-sensitive adhesive tape for explosion-proof cathode ray tube according to claim 1, wherein the endothermic substance is contained in a base material. 9. The pressure-sensitive adhesive tape for explosion-proof cathode ray tubes according to claim 1, wherein the heat-absorbing substance is contained in an adhesive. 10. The method according to claim 1, wherein the endothermic substance is contained in both the substrate and the adhesive.
The pressure-sensitive adhesive tape for explosion-proof cathode-ray tubes according to any one of claims 1 to 4.