JPH0130878B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is particularly applicable to a cathode ray tube implosion prevention reinforcement method in which a tightening band is tightened around the outer circumference of the cathode ray tube by heating it to 200°C to 500°C. This invention relates to an explosion-proof adhesive tape that is wound between the valve side of a pipe and a tightening band. [Prior Art] The present applicant has previously proposed an explosion-proof tape in which an inorganic particulate material is blended into the adhesive layer, which can be applied to the cone-shaped portion behind the maximum outer diameter of the bulb of a cathode ray tube. However, although the tape of the above invention was effective in solving the problem that the tightening band misaligned from the intended position of the valve of the cathode ray tube, it was difficult to tighten the tightening band after winding the tape in the production process. When tightening the attached band, the inorganic particles contained in the adhesive layer of the tape come into direct contact with the glass surface of the bulb due to the pressure and heat of the heated band, causing damage to the glass surface due to friction. In some cases, it has been found to be disadvantageous that local defects may occur on the valve surface, increasing the risk of implosion, and that the method of tightening is therefore limited. [Object of the Invention] An object of the present invention is to provide an explosion-proof adhesive tape for use in reinforcing cathode ray tubes, which improves the above-mentioned drawbacks. [Structure of the Invention] The present invention provides particles having a particle size of 125μ or less on one or both sides of a sheet-like base material having a thickness of about 25μ to 125μ,
In addition, powder with a particle size of 50μ or more accounts for 30% of the total powder.
It has a particle size distribution of % by weight or more and a heat distortion temperature of
Coating and forming an adhesive layer containing 5 to 150 parts by weight of thermosetting resin cured powder having a temperature of 105°C or higher based on 100 parts by weight of the solid content of the adhesive to a thickness of 35μ to 100μ. This is an explosion-proof adhesive tape used to reinforce cathode ray tubes. In order to improve the above-mentioned drawbacks of the prior art, the present inventor conducted research on the relationship between the adhesive composition of explosion-proof adhesive tapes and slippage. It has been found that by adding it, it does not damage the glass surface of the cathode ray tube bulb, and it is possible to impart extremely high shear resistance even to the conical part of the bulb. The thermosetting resin cured powder used in the present invention is a thermosetting resin such as epoxy resin, phenolic resin, unsaturated polyester resin, melamine resin, etc. that has a heat distortion temperature of 105°C or higher together with a curing agent and various compounds. This hardened product is crushed with a crusher, and then the particle size is reduced with a ball mill.
It is adjusted so that the content of particles having a particle size of 125μ or less and 50μ or more is 30% by weight or more based on the entire powder. The adhesive to be mixed with the thermosetting resin cured powder may be a rubber-based adhesive made by adding a tackifying resin to commonly used natural rubber or synthetic rubber, or a rubber-based adhesive whose main component is an acrylic ester copolymer. Resin-based adhesives are used, and the solid content of these adhesives is 100%.
5 parts by weight of the cured powder of the thermosetting resin
It is desirable that the adhesive layer containing the cured product powder, which is formed by mixing in a range of parts by weight to 150 parts by weight and applying this to at least one side of a sheet-like substrate, has sufficient initial adhesion to the glass surface. In addition, the adhesive layer on the band surface may have adhesiveness equal to or lower than that on the glass surface, or may not be present at all. That is, it is not necessary to apply an adhesive. If the heat deformation temperature of the cured powder mixed in the adhesive is 105℃ or less, the powder will gradually soften due to heat generation when using a cathode ray tube, causing displacement of the tightening band and explosion-proof reinforcement. There is a risk that it will become useless. In addition, when using a cured product powder with a particle size of 125μ or more, when forming an adhesive layer on a sheet-like base material, streaks with no adhesive layer may occur, or particles may be caught between the base material and the roll. This may cause the base material to be cut, or the surface of the formed adhesive layer may be extremely uneven, resulting in an extremely small adhesion area, resulting in poor initial adhesion to the glass surface of the bulb. In addition, particles with a particle size of 50μ or less account for 70% by weight of the total powder.
When the above amount exists, the inherent adhesive force and tackiness of the adhesive are significantly reduced, making it impractical. Since the adhesive formulation containing the cured thermosetting resin powder of the present invention has a similar specific gravity between the powder and the adhesive compared to inorganic granules, there is no extreme powder precipitation, and there is no sheet-like base material. There are advantages such as less scattering of powder on the adhesive layer formed on the material. The sheet-like base material of the adhesive tape used for the above purpose is a film made of a polymer compound such as polyester or vinyl chloride, paper such as Japanese paper or rayon paper, cloth or non-woven fabric made of glass fiber or polyester fiber. Furthermore, any sheet-like base material can be used, such as metal sheets such as aluminum foil or steel foil. The thickness of the above-mentioned sheet-like base material is selected in the range of 25μ to 250μ depending on the bulb design of the cathode ray tube to which it is applied. In terms of flexibility), it is preferable for film base materials to be thin, and for other base materials to be relatively thick. To manufacture the adhesive tape according to the present invention, a solution containing the above-mentioned adhesive and powder of a cured thermosetting resin is applied to each side with a roll coater or both sides simultaneously with a dip coater to a predetermined thickness,
Next, it is dried to form an adhesive layer containing the cured product powder on one or both sides of the base material, wound up as it is or together with release paper, and cut into a predetermined width to obtain an explosion-proof adhesive tape. Embodiments of the explosion-proof adhesive tape and its application according to the present invention will be described based on the drawings. FIG. 1 shows a cross-sectional view of the explosion-proof adhesive tape 5 obtained as described above, in which adhesive layers 1 on both sides of the base material 2 are mixed with the above-described cured thermosetting resin powder 4.
and 3 are formed. This adhesive tape 5 is attached to the outside 6 of the cathode ray tube bulb as shown in FIG.
It is simultaneously tightened and pressurized by a heated metal tightening band 7. At this time, the adhesive layer 1 facing the glass surface 6 of the bulb and the surface of the band 7,
3, even if the contained powder 4 is dragged in the vertical direction of FIG. 2 while directly contacting the glass surface 6 of the bulb, the powder 4 will not be damaged.
The heat and pressure of the band 7 cause the powder 4a to bite into the base material 2 and the glass surface 6 due to thermal deformation of the powders 4b and 4c, as shown in an enlarged view in FIG. By adapting to the band surface 7, the anchoring force to the base material 2, the glass surface 6, and the band surface 7 is strengthened, and as a result, the misalignment of the band 7 and the glass surface 6 is prevented, and the tightening force of the band 7 is faithfully maintained. to the glass surface 6, exhibiting better fixing performance than conventional adhesive tapes and providing stable explosion-proof performance. It is clear from the above explanation that the adhesive tape for explosion-proofing cathode ray tubes according to the present invention is an extremely effective means for fixing bands for reinforcing the outer peripheral surface of cathode ray tube bulbs. In some cases, it has the advantages mentioned above compared to conventional tape. Examples of the present invention will be described below, but it goes without saying that the present invention is not limited to these examples. Example 100 parts by weight of bisphenol A type epoxy resin with an epoxy equivalent of 185 and 3 parts of 2-ethyl-4-methylimidazole were mixed and heated at 150°C for 30 minutes.
A cured epoxy product with a heat distortion temperature of 158°C was prepared.
Particle size is 50 using crusher and ball mill.
A cured epoxy resin powder divided into powders of ~105μ and powders of 50μ or less and mixed so that the weight ratio of each group was 1:1 was added to 100 parts by weight of the solid content of a butyl polyacrylate adhesive. An adhesive solution containing 10 parts by weight of mixed powder was prepared. Put this solution into a pad, apply it on both sides of a 75μ thick polyester film using a dip coater so that the thickness of the finished adhesive layer on the front and back is 65μ each, dry it, roll it up with release paper, and apply the explosion-proof adhesive tape. Created. Table 1 shows the results of measuring the adhesiveness and shear characteristics when this adhesive tape was cut to a width of 21 mm and wound around a pyramid. This tape was further wrapped around the outside of a 12-inch (36.36 cm) color cathode ray tube, and banding was then performed by tightening a 20 mm wide iron band onto the tape while heating it to 300°C. We observed the amount of deviation after banding, the amount of deviation after heat cycle, and the amount of deviation after forced deviation test, and in all cases, as shown in Table 1 as the mounting test results, it was less than 1 mm, which is an excellent fixing effect. showed that. Further, after banding, the band was cut, the tape was peeled off, and the state of the glass surface to which the tape was applied was observed. There were no scratches at all, indicating the excellent quality of this tape. 【table】

[Brief explanation of drawings]

Figures 1, 2, and 3 are drawings for explaining embodiments of the present invention. Figure 1 is a sectional view of the adhesive tape of the present invention, and Figure 2 is a cross-sectional view of the adhesive tape attached to the outside of the cathode ray tube. FIG. 3 is an enlarged view of the cross-sectional view shown in FIG. 2. DESCRIPTION OF SYMBOLS 1, 3... Adhesive layer, 2... Base material, 4... Cured thermosetting resin powder, 6... Outside the bulb of the cathode ray tube, 7... Metal tightening band.

Claims (1)

[Claims] 1 Particles with a particle size of 125μ or less and 50μ
Powder having a particle size of 30% or more of the total powder and a heat distortion temperature of 105°C or higher. An explosion-proof adhesive tape for use in reinforcing cathode ray tubes, which is formed by coating an adhesive layer containing an adhesive layer in the range of 5 to 150 parts by weight to a thickness in the range of 35 to 100 microns.