JPS6324291B2 - - Google Patents

Description

[Detailed description of the invention]

Currently, explosion-proof systems for cathode ray tubes used in televisions, etc., mostly employ side or rear protection systems, depending on image quality, reinforcing effects, and suitability on production lines. This method creates distortions on the walls by keeping the inside of the cathode ray tube, which has a unique shape, in an extreme vacuum, and when an impact is applied to the front of the cathode ray tube, reverse distortion occurs and the outer surface of the cathode ray tube bulges. In order to prevent it from being destroyed in the future, the outer surface is reinforced by tightening it with a metal tightening band. In such a system, it is necessary to effectively transmit the tightening force of the tightening band to the surface of the cathode ray tube, and for this purpose, an effective and strong adhesive member must be interposed between the inside of the tightening band and the surface of the cathode ray tube. If this effective adhesive member is not present, tightening the band will cause the band to slip due to the curved surface of the CRT, and the reinforcing effect will be lost, or the band will come into direct contact with the CRT surface and the surface will be damaged. However, there are disadvantages such as damage to the tube, resulting in weak spots locally, and the fact that the tube bulges to the outside, causing the tube to expand sufficiently using the corner as a fulcrum. There are drawbacks that prevent it from fulfilling its purpose. On the other hand, when an effective adhesive exists, it prevents cracks from forming at the front of the cathode ray tube after impact.
In addition, even if a crack occurs in this area, the resulting bulge on the outer surface is limited to the force that stretches the band only in a very limited area around the crack, and the crack is It stops directly under the tightening band and at the same time prevents it from breaking. Even if the cathode ray tube were to break, the pieces would be retained by the adhesion to the tightening band, and the scattering of the broken glass pieces would be kept to a minimum. The present invention relates to a method for reinforcing cathode ray tubes using a novel adhesive tape as an adhesive member, which was invented with attention to the above points.It is highly suitable for automation, and is effective and effective between the tightening band and the surface of the cathode ray tube. To provide strong adhesion, a hot-melt adhesive that has good adhesion to the clamping band is applied to one side of the substrate, which has excellent strength against compression cutting, and an excellent adhesion agent that shows good adhesion to the glass surface is applied to the other side. This invention relates to a method for reinforcing cathode ray tubes in which an adhesive tape made of a pressure-sensitive adhesive with cohesive properties is interposed. Conventionally, one of these adhesive methods used a two-component thermosetting adhesive, but when using such an adhesive, a rim band was interposed inside the tightening band, and the rim band Applying adhesive to the inside of the adhesive requires a complicated process, resin oozes out during banding, and requires a large-scale two-component mixture to deal with the pot life of the adhesive. , it is necessary to invest in a large-scale production line such as a long curing furnace to accelerate curing and large-scale ventilation equipment to prevent the toxicity of the curing agent, resulting in energy wastage, health and safety issues, and increased costs. And so on. Another method involves wrapping a pressure-sensitive adhesive tape made of film, paper, cloth, etc. around the cathode ray tube.
There is also a method of applying a tightening band over the tape, but if the tightening force is too strong for large cathode ray tubes, etc., the base material may be cut and the band may come into direct contact with the surface of the cathode ray tube, or the release surface of the tightening band and tape may be damaged. Since there is no adhesive between them, the tightening band may shift from the tape surface, and the tightening force of the band cannot be transmitted effectively, and the types of cathode ray tubes to which it can be applied are extremely limited. To overcome these drawbacks, prepreg, which has a base material impregnated with thermosetting resin, and double-sided adhesive tape, which has adhesive applied to the front and back sides, are used, but prepreg has a short pot life and is difficult to manage. However, there are problems in that it is difficult to set the curing conditions, it is difficult to obtain uniform adhesion, and it is necessary to apply high temperatures to carry out the curing reaction. Due to relationship difficulties,
The heating temperature is limited to about 80°C, which has the disadvantage of requiring a long curing time. When using an adhesive, due to the adhesive's permanent flow properties, the adhesive may protrude from the tightening band during banding, causing poor appearance such as dust adhering to the protruding adhesive surface, or aging due to the adhesive flowing. Installation and disposal of separators used to prevent the tightened band from shifting from its intended position and no longer exhibiting a reinforcing effect, or from blocking on the double-sided tape. There were problems, and none of them could be a satisfactory reinforcement method. On the other hand, in order to increase the size and miniaturization of cathode ray tubes and to strengthen their safety measures, heating banding methods have been increasing in recent years, which increase the tightening force of the band and utilize the expansion caused by heating and contraction caused by cooling. Ta. The purpose of this is to tighten and hold down the force W that tends to spread toward the outer circumference due to the impact applied to the front surface of the cathode ray tube, and the expansion force F of the band.The relationship between W and F is as follows. It is as follows. W=K/F...(1) Here, K is a constant determined by the structure of the cathode ray tube and the adhesion between the band and the cathode ray tube. This heating banding method not only increases the clamping force F, but also allows the metal band heated to a high temperature and stretched to reach the plastic deformation region, and also improves its adhesion to the outer surface of the cathode ray tube, which has a three-dimensional curved surface. This has the advantage that the tightening force of the band is transmitted to the cathode ray tube very effectively. Therefore, this method not only applies the large clamping force required for large pipes, but also applies to small pipes, where conventional tension tightening methods at room temperature tend to cause tension down when removing the tightening jig. It has the advantage of providing tightening tension. The purpose of the present invention is to obtain a reinforcement method for a cathode ray tube that is effective for this heating banding method, and by providing effective adhesion between the outer surface of the cathode ray tube and the band,
By reducing the value of , and by reducing the bulge W on the outer surface with a large tightening force F, cracking of the cathode ray tube is prevented, and in addition, the explosion-proof effect is enhanced. In order to achieve the above object, the present invention uses the adhesive side of an adhesive tape to adhere to the entire circumference of the outer surface of a cathode ray tube or only to a necessary part to form an adhesive member between the cathode ray tube and the tape, and then Preferably, it is heated to 350° C. to 450° C. to expand it, or it is tightened by fitting a tightening band stretched above the yield point. At this moment, the hot-melt adhesive on the adhesive member that is in contact with the heating band melts and solidifies as the band cools, forming a strong bond between the tightening band and the tape. The present invention relates to a method of reinforcing a cathode ray tube, in which the band is integrated with a tape as a boundary, and the tightening force of the band is effectively transmitted to the surface of the cathode ray tube. Here, this adhesive effect is caused by a force W exerted on the cathode ray tube that tends to expand outwards, and when looked at in detail, this expanding force tends to cause cracks, and when cracks occur, the grooves Even if this force exceeds the band's tightening force, it partially suppresses the band's elongation and minimizes cracks. Furthermore, in this reinforcement method,
The tape base material has sufficient pressure resistance against the pressure of the band tightened by this method, and prevents the occurrence of defective adhesion points due to cutting of the base material, and also prevents the band from directly hitting the surface of the cathode ray tube and damaging it. In addition, even if this cathode ray tube were to be destroyed, the glass fragments would be effectively adhered to the band with the tape intervening, which would have the side effect of minimizing the risk of the dangerous glass fragments being scattered. To explain the present reinforcing method using drawings, FIG. 1 is a perspective view of the reinforcing method according to the present invention in use, and FIG. 2 is a sectional view of the reinforcing method in use. 1 in the figure is a cathode ray tube,
3 is adhesive tape, 2 is a tightening band,
is the base material of the tape 3, and an adhesive 5 is coated on one side of the base material 4, and a hot-melt adhesive layer 6 formed on the opposite side has an excellent release property with respect to the adhesive 5. It has moldability and excellent adhesion to the base material 4, and when it comes into contact with the heated band 2, only the contact portion is thermally melted and bonded. The tape 3 has a step part at the mold mating part,
The base material 4, which has excellent compression cut resistance, works effectively for this stepped portion. The adhesive 5 is an adhesive that has good adhesion to glass surfaces and high cohesiveness that resists shearing, and also has high adhesion to the base material 4. The hot-melt adhesive 6 of the adhesive tape 3 used in the reinforcing method of the present invention has good film-forming ability, has a melting point of 80°C to 200°C, is flexible at room temperature, and has high adhesiveness to metals. A peel force of at least 500 at 180℃ after melt bonding is used.
g/10mm width or more is preferred, ester resin, acrylic graft polyethylene, ethylene-
Resins such as vinyl acetate copolymers, styrene-butadiene copolymers, ethylene-acrylic copolymers, polyamides, etc., alone or in combination, are used and are selected for use in thicknesses of 50 microns to 150 microns depending on the type. If the surface of the adhesive layer 6 has sufficient mold release properties with respect to the adhesive 5 on the opposite side, it can be used as is, but if it is insufficient, a small amount of mold release agent is applied. The adhesive 5 used on the opposite side is an acrylic or rubber adhesive that has a peeling force of 500 g/10 mm width or more at 180°C to the glass surface, and preferably provides appropriate cohesion. Therefore, it is a thermosetting adhesive with a small amount of hardening agent added to these, and it is desirable that it does not shift when heat banding is applied to the glass surface.
It is used in a thickness range of 150μ to 150μ. Non-thermosetting adhesives can also be used, but in this case, if they are used on a gently sloped surface and cause slippage during banding, they are limited to being used only on mold mats that can get caught. Materials used as the base material 4 include glass cloth, polyester cloth, vinylon cloth, cloth, cotton cloth, and polyester film. More severely, the pressure is concentrated on the mold matches on the surface of the cathode ray tube, the welded parts of the band, the ear attachment parts, etc., and this pressure is a total pressure of 700~
At 1500Kg/ ^cm2 , a maximum force of 20-30Kg/ ^cm2 is applied in some areas. The guideline for meeting the conditions for withstanding this pressure varies depending on the type of base material 4, but for glass cloth, at least weft threads with a thickness of 75 or higher are used, but the pressure resistance of this weft diameter is determined by mold match accuracy. Depending on the type of pipe, threads with a thickness smaller than this can be used as well, depending on the type of pipe. When using synthetic fibers such as polyester cloth, it is generally preferable that the thickness of the base material 4 is 0.3 mm or more. When using a polyester film, a thickness in the range of 75μ to 135μ is most appropriate in view of its adaptability to the curved surface of the cathode ray tube and the compressive shear strength of the film. Furthermore, cotton cloth, staple cloth, etc. are used with a thickness of 0.2 mm or more, but although these base materials are extremely weak in strength, they are effective because the fibers themselves that form the cloth in a pressurized state The fibers unravel, resulting in the formation of gaps, and the fibers themselves have relatively little shrinkage, resulting in excellent high-temperature stability and a fixing effect for the resin layer. Due to these circumstances, it is possible to use the base material 4 made of various materials, but in general, the adhesive 6 and adhesive 4 have low elongation that contributes to the fixing effect, reliability against high temperatures during banding, and each corner. Since the impact of local compressive cutting force on nearby ears and their welding protrusions, as well as on the joints of tightening bands, is greatest, glass cloth bases are not recommended in consideration of appearance, thickness, workability, cost, etc. wood is often used. To manufacture the adhesive tape 3 used in the present invention, a hot-melt adhesive that has been melted in advance at a temperature of 250°C to 450°C is made into a film using an extruder and laminated onto the base material 4, or In the case of a resin or its compound that does not get wet, it can be applied or impregnated directly onto the base material 4 using a roll coater or dip coater, or
After forming a film on the separator, it is transferred to the base material 4 to form a heat-melting adhesive layer 6. The pressure-sensitive adhesive layer 5 on the opposite side is applied using a roll coater if it is a solvent-based adhesive, or a calender if it is a solvent-free adhesive. It can be extruded and applied at the same time as the agent layer 6. The adhesive tape 3 manufactured in this way is
It is supplied slit to the required width for automatic winding. Of course, since the mold releasability between the adhesive layer 6 and the pressure-sensitive adhesive layer 5 is excellent, a separator is not required. Therefore, the taping machine for pasting onto the cathode ray tube may have a simple structure, and at the same time, since the adhesive tape 3 is necessarily strong as a base material, there is an advantage that the taping operation can be performed at high speed. A metal fastening band that has been expanded or forcibly stretched beyond the yield value of the material by induction heating or flame heating is fitted or tightened onto the taped cathode ray tube. At this time, the tightening force is determined by the tensile force of the band and the contractile force that starts from the moment the heated band touches the cathode ray tube at room temperature, so the heating condition for the band is a high temperature that extends to above the yield point of the material. It is quite advantageous. However, due to thermal distortion due to the temperature difference with the surface of the cathode ray tube, and at the moment of contact with the adhesive tape, only the contact area becomes integrated with the cathode ray tube through the adhesive tape, and along with its excellent clamping force, it has excellent Exhibits a reinforcing effect. In particular, in the reinforcement method using adhesive tape 3 with a fabric base material, the adhesive layer melted by heat and pressure during banding reaches the glass surface, so the permanent fluidity of the adhesive is fixed. As a result, the adhesive force between the cathode ray tube and the band is improved, and the fixing force of the adhesive layer is improved, making it possible to obtain a higher reinforcing effect. Furthermore, the adhesive layer 6 exposed on the surface, which is not in contact with the tightening band, maintains its beautiful appearance without picking up dust or the like. Even if a cathode ray tube reinforced in this way is found to have an abnormality during the final inspection process and needs to be recovered,
It has the advantage that it can be easily removed by simply cutting the tightening band and peeling it off at 180 degrees without leaving any adhesive residue on the surface of the cathode ray tube, minimizing production loss. . The numerous advantages of the method of reinforcing cathode ray tubes using the adhesive tape of the present invention described above make it an extremely effective method for producing highly safe cathode ray tubes efficiently and at low cost. This will be explained using an example. The present invention is not limited to these examples. Example Base material 4 has a thickness of 0.18 mm and a weave density of 35 in the warp direction.
Book/25mm (thread count: 150) 30 pieces in weft direction/25mm (thread count: 75) Ethylene-acrylic acid copolymer with a softening point of 85°C as hot melt adhesive 6 on one side of aminosilane-treated plain-woven glass cloth (MI=4, acrylic acid content 8%) using an extruder at a temperature of 350
After laminating by extrusion at ℃ to a thickness of 70μ, an acrylic adhesive with a trace amount of tolylene diisocyanate added to the other side was applied to a thickness of 50μ using a roll coater, cross-linked, and wound into a paper tube to form a viscous adhesive. Adhesive tape 3 was manufactured. This tape had good releasability of the adhesive surface 6 to the adhesive surface 5, and no blocking of the adhesive or separation of the adhesive from the base material was observed. Furthermore, the general performance of this tape is that the overall thickness is 0.3mm.
The adhesion to glass plates and steel plates was measured using a testing machine (Instron model 1131) that applied a pressure of 10 kg/cm ² for 5 seconds at 300°C.
The 180° peeling force of the adhesive side to the glass plate and the shear adhesion force to the glass plate are 2.2Kg/30mm width (pulling speed 300mm/min) for the former and 12.5Kg/cm ² (pulling speed 50mm/min). Similarly, the 180° peeling force and shear adhesion force to the steel plate of the adhesive surface were 2.6 Kg/30 mm width and 25.8 Kg/cm ² , respectively. Cut this tape to a width of 33 mm, wrap it once around the outside mold match step of the 20-inch color TV cathode ray tube 1 (approximately 1.5 m), and then tighten the tape by heating it to approximately 350°C by induction heating. Band (surface oxidized steel plate with Mn content of 0.7%)
2 was pulled and tightened with a force of approximately 50 kg/30 mm width to create an explosion-proof device. The reinforcing effect of this explosion-proof equipment was confirmed by the crack pattern analysis by the front human test, the scattering distribution by the drop test, the amount of deviation by the forced shear test, and the tension down value by the heat cycle test, all of which showed good results. It was recognized that the (See table) The contribution of this reinforcement method to the specific explosion-proof properties was clarified by destroying the cathode ray tube and evaluating the shape of the adhesive tape and its adhesive strength with the cathode ray tube surface and tightening band. Then,
No breakage was observed in the tape base material even on corner mold matches where pressure was concentrated, and only slight weaving occurred. Furthermore, vs. cathode ray tube 1
The peeling force to the surface was 1.85Kg/33mm, and the peeling force to the paired band 2 was 2.68Kg/33mm, indicating good adhesive strength. As mentioned above, the reinforcing method of the present invention not only has excellent explosion-proof properties, but also has excellent appearance, and the effectiveness of this method has been demonstrated by showing numerical values that specifically contribute to explosion-proof properties. Example 2 A hot-melt adhesive 6 with a softening point of 125 was applied to one side of a polyester film with a thickness of 0.1 mm as the base material 4.
℃ ester resin (modified polyester resin) is diluted with toluene and coated using a roll coater.
Coat to a thickness of 50μ, dry, and add about 0.18g/approx. of isocyanate-alcohol co-reactive mold release agent on top.
m ² was coated to obtain a heat-melting adhesive sheet 6. On the other hand, a pressure-sensitive adhesive composed of natural rubber and a rosin acid derivative is applied to the opposite side of this sheet using toluene as a solvent to form an adhesive layer 5 with a thickness of 50μ, dried, and then wound around a paper tube and adhesively bonded. A tape 3 was manufactured. The general performance of this tape is as shown in Table 1. A 21 mm wide slit tape is wrapped around a 9 inch cathode ray tube (approximately 1 m), and the inner diameter is 95% of the outside diameter of the cathode ray tube with a width of 19 mm. The metal band 2, which had been welded in advance, was induction heated to 420°C and fitted to provide explosion-proof reinforcement. The explosion-proofing effect of this reinforcement was evaluated in the same manner as described in Example 1, and good results were obtained. The cathode ray tube 1 was destroyed and adhesion was evaluated at each site. The results are shown in Table 1. Example 3 Base material 4 has a thickness of 0.22 mm and a weave density of 50 in the warp direction.
A hot melt roll coater with polyamide resin (amine value 0.5 or less) with a softening point of 185°C as a hot-melt adhesive kept at 250°C on a 25mm fabric (thread count 30), 40 threads in the weft direction/25mm. The adhesive layer is 60μ
0.1 g/m ² of the release agent of Example 1 was applied to the surface of the adhesive sheet to obtain a hot-melt adhesive sheet 6. Next, a solid natural rubber adhesive was applied to the opposite side to a thickness of 70 μm, and the tape was wound around a paper tube to obtain an adhesive tape 3. This tape 3 was applied to the same cathode ray tube 1 as in Example 2 by the same method, and the explosion-proof function was evaluated using the same explosion-proof equipment. Although the results were good, when inspecting the shape of the tape after destruction, some parts were found to be on the verge of being cut. From this, the lowest level difference of the mold mating part of this cathode ray tube was 0.25 mm, so the reinforcing method using this tape was effective within this level difference. (See Table 1) Example 4 A composition in which a styrene-butadiene copolymer with a softening point of 128°C as a main component and rosin and petroleum resin were blended as a hot-melt adhesive on one side of the glass cloth of Example 1 as a base material. Using a hot melt roll coater kept at 250°C, the adhesive layer 6 was coated to a certain thickness.
Apply it to a thickness of 70μ, and then apply Example 1 on the opposite side.
The adhesive was applied to a thickness of 50 μm, dried 5, and wound around a paper tube to obtain an adhesive tape 3. This tape was applied to the same cathode ray tube 1 as in Example 1 by the same method, and the explosion-proof function was evaluated using the same explosion-proof equipment. The results were good as shown in Table 1. Example 5 The base material has a thickness of 0.24 mm and a weave density of 25 in the warp direction.
Ethylene-vinyl acetate copolymer with a softening point of 95°C as a hot-melt adhesive on one side of aminosilane-treated glass cloth, 25mm (thread count: 150 x 2), 25 in the weft direction (thread count: 75) (Vinyl acetate content 10wt
%) was extruded under extrusion conditions at 350°C to a thickness of 60μ, and laminated onto a base material. Next, the solid natural rubber adhesive of Example 3 was applied to the opposite side using a calender to a thickness of 60 μm (5), and the tape was wound into a paper tube to obtain an adhesive tape (3). Cut this tape to a width of 38 mm and wrap it around the entire circumference (approximately 2.05 m) around the outer surface of the 26-inch color TV CRT 1 (maximum mold mating step 0.5 mm), and then wrap it around the entire circumference (approximately 2.05 m) with a width of 35 mm and an inner diameter relative to the outer diameter of the CRT.
The metal band 2, which had been welded in advance to a 94.5% strength, was heated to 450°C by induction heating and then fitted to provide explosion-proof reinforcement. The explosion-proof effect of this reinforcement was good as shown in Table 1, and the adhesion between the cathode ray tube 1 and the tightening band 2 was also satisfactory. Comparative Example 1 The solid rubber adhesive of Example 3 was applied to both sides of the base material 4 of Example 1 using a calender to reduce the finished thickness.
It was coated to a thickness of 0.25 mm and rolled into a paper tube together with a separator to make a double-sided adhesive tape with a glass cloth base. This tape was used to equip a 20-inch cathode ray tube 1 with explosion-proof equipment in exactly the same manner as in Example 1, and its explosion-proof function was examined. As a result, although the explosion-proof properties were satisfactory as shown in Table 1, the resin protruded, the accompanying dust adhesion, misalignment during banding, and furthermore, the separator was wrapped together with the tape during taping, and the guide roll There were disadvantages such as being caught in the middle of the day. Comparative Example 2 A polyester film adhesive tape with a width of 33 mm and a thickness of 50 μ and coated with an acrylic adhesive mainly composed of acrylic acid ester on one side to a thickness of 25 μ was applied to the same cathode ray tube 1 as in Example 1 by the same method. The explosion-proof function was investigated by installing the explosion-proof equipment. As shown in Table 1, abnormalities were observed in both the front side hit and drop tests, and at the same time, it was observed that the tightening band 3 was displaced from the back side of the tape. Furthermore, when the band was cut and the condition of the tape was observed, it was found that it was cut on the mold match line over almost the entire circumference, and the entire band was in direct contact with the cathode ray tube, especially at the corners, causing scratches on the surface of some parts of the cathode ray tube. Some areas were found to be stained. When forced destruction was subsequently performed, the glass fragments of the cathode ray tube were not in contact with the tightening band, so there was a disadvantage that they were scattered in no direction.

【table】

[Table] From the above examples, the reinforcing method of the present invention in the heating tightening method of the tightening band is superior not only in explosion-proof function but also in wrapping workability and finished appearance.
It is clear that it has an effect that also contributes to cost.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a cathode ray tube wound with adhesive tape and a tightening band fitted thereon, and FIG. 2 is a cross-sectional side view thereof. DESCRIPTION OF SYMBOLS 1... Glass of a cathode ray tube, 2... Tightening band, 3... Adhesive tape, 4... Base material, 5... Adhesive, 6... Heat-melting adhesive layer.

Claims (1)

[Claims] 1. Even if there is a linear stepped part with a height of 0.6 mm or less, the lateral strength is at least 10 to 30 kg/
A hot-melt adhesive with a melting point of 80 to 200°C is applied to one side of a base material that has a compressive cutting strength that does not break even when subjected to pressure in the ^cm2 range, and a pressure-sensitive adhesive is applied to the other side. A reinforcing method for cathode ray tubes characterized by interposing adhesive tape between the cathode ray tube and the tightening band. 2 Explosion-proofing effect can be achieved by attaching adhesive tape to the outer surface of a cathode ray tube over its entire circumference or in part, and then bringing a tightening band heated to at least 120℃ or higher onto the tape to melt and adhere it. Claim 1 characterized by increasing the
The reinforcement method for the cathode ray tube described.