JPH0331483B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to an improved electrostatic air filtration filter. (Prior Art) Conventional air filtration filters of this type generally have:
Using wool or synthetic fiber as a base material, this is impregnated with resin, and then mechanical external forces such as squeezing, bending, beating, and crushing are applied to generate static electricity. In wool-based filters, a resin made from a condensation reaction product of paratertiary butylphenol and formalin is used as the impregnating resin, and static electricity generated by external mechanical force is almost always in the form of permanent charging. However, the drawback was that the amount of static electricity itself generated was relatively small. In other words, it is less likely to deteriorate over time, but the original amount of static electricity is small,
Therefore, the dust collection capacity was small. On the other hand, filters based on synthetic fibers generate a much larger amount of static electricity due to mechanical external forces during manufacture than wool filters. However, this static electricity has the major drawback of being easily discharged, making it difficult to use as a filter. (Purpose of the Invention) Therefore, the present invention uses a felt made of a mixture of wool and polyester fibers as a base material, and also uses two types of resins to impregnate the felt, and uses wool as a base material as shown in the prior art. The purpose of the present invention is to provide an electrostatic air filtration filter that has a strong electrostatic force and has little deterioration over time, by mutually compensating for the disadvantages of using synthetic fibers and synthetic fibers as base materials. Hereinafter, the present invention will be explained in detail with reference to Examples. (Example) As a base material, a breathable web made of a mixture of 70-50% wool and 30-50% polyester synthetic fibers is used, which is formed into a felt shape by wool filling or needle punching. . Here, as polyester fiber, A fiber with the basic structure is used. In addition, as a resin, paratasyabutylphenol Add 40 g of 28% ammonia as a catalyst to a mixture of 250 g and 300 g of 36% formalin, heat at about 100°C for 1 hour, and then further heat at about 180°C for 3 hours to obtain a yellowish brown condensation reaction product. Resin A and indene (

[Formula]), Kumaron (

Add 28% ammonia as a catalyst to a mixture of 200g of the mixture of [formula]) and 300g of 36% formalin.
40g was added and heated at about 100°C for 1.5 hours, and then further heated at about 160°C for 5 hours to obtain a pale yellow condensation reaction product, which was designated as Resin B. Using the above base material, resin A, and resin B as raw materials, first, use a solvent 1 having a boiling point of around 70 to 100°C, such as trichlorethylene, to dissolve both resin A and resin B.
A mixed solution C is prepared by dissolving 27 g of resin A and about 30 g of resin B in the following. Next, this mixed solution C
The base material, a strip of felt, is continuously immersed in the water, the excess solution is squeezed out with a roll, etc., and then the temperature is about 100°C.
Heat and dry. Next, static electricity is generated by applying external mechanical force such as bending, hitting, or pushing with a needle or the like to generate static electricity, which is used as a filter. As shown in FIG. 1, the filter constructed as described above has wool fibers 1 and polyester fibers 2.
Resin A and resin B are attached to each. Among these, the amount of static electricity generated between the polyester fiber and resin B is extremely large when an external mechanical force is applied, but it is generally easy to discharge, but in the present invention, the amount of static electricity generated is As shown, since wool fiber 1 and resin A are always present in contact with or in close proximity to polyester fiber 2 and resin B, discharge is suppressed by their electrostatic influence. On the other hand, the wool fiber 1 and resin A are affected by the strong electrostatic force generated between the polyester fiber and resin B, which also results in a strong charge. In short, they electrostatically influence each other to generate a large amount of static electricity, and moreover, the charge is maintained almost permanently. The appropriate mixing ratio of polyester fiber to wool fiber is 30 to 50%; if it is less than this, the amount of static electricity generated initially will be small, and if it is too much, deterioration over time will increase. Table 1 shows filter characteristics when the mixing ratio of wool (W) and polyester fiber (P) is changed in the above manufacturing method.

【table】

[Table] As is clear from Table 1, the dust collection efficiency increases almost proportionally until P is mixed in at 40%.
% mixture, deterioration over time appears after 6 months. The dust collection efficiency was determined in accordance with the national certification for dust masks. The amount of charge was measured as the amount of charge Q (coulombs) per weight (g) of the filter using an electrometer using a Faraday cage. Table 2 shows the characteristics when using 60% wool and 40% synthetic fibers, changing the type of synthetic fibers, and using A and B as the impregnating resin. Here, in addition to polyester (P) 3d (denier), rayon (L) 1.5d, acrylic (A) 2d, polypropylene (PP) 1.5d, and nylon 6(N) 2d were used as synthetic fibers.

[Table] Type 5 W (wool) + P (polyester) in Table 2
is the same as 5 in Table 1. The fiber of the present invention, which uses polyester as a synthetic fiber, has a thickness of 3.0 d compared to those using other synthetic fibers.
Even though it is thick, it has extremely good dust collection efficiency and charge amount, and has very little change over time. Next, Table 3, similar to Table 2, shows the characteristics when the type of synthetic fiber was changed, with 60% wool and 40% synthetic fiber, and only A was used as the impregnating resin.

[Table] In this case, W (wool) + P (polyester) is
At the time of manufacture, the dust collection rate was 99.992%, showing extremely high performance, but after 6 months, it had dropped to 99.3%, indicating significant deterioration over time. Those using synthetic fibers other than polyester still have inferior characteristics. (Effects of the Invention) As explained above, according to the present invention, the respective drawbacks of the wool-based filter and the synthetic fiber-based filter are compensated for by each other, and a large amount of static electricity is generated. By maintaining this, the dust collection capacity increases, and by suppressing discharge, deterioration over time becomes extremely small, and the performance as a filter can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the relationship between fibers and resin in the present invention, and FIG. 2 is an enlarged diagram showing the main parts of the same relationship. 1...Wool fiber, 2...Polyester fiber, A, B
…resin.

Claims (1)

[Claims] 1 At least 30% polyester synthetic fiber in wool,
A mixed resin of resin A consisting of a condensation reaction product of paratertiary butylphenol and formalin and resin B consisting of a condensation reaction product of a mixture of indene and coumaron and formalin is added to the felt mixed at a ratio of less than 50%. An electrostatic air filtration filter characterized by being impregnated with water and subjected to electrostatic treatment by applying an external mechanical force to the filter.