JPH0559768B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to glass fiber paper for ultra-high performance air filters for air purification in the manufacture of MOS dynamic RAM and the like in the semiconductor industry. (Prior art) Conventionally, glass fiber paper for air filters has been able to capture more than 99.999% of particles with a particle size of 0.3μ.
HEPA paper is well-known, and it is folded into a zigzag shape, folded in a wavy manner, and inserted into a zigzag spacer between each side of the paper so that the opposing paper sides do not overlap, and then inserted into a surrounding frame. death,
Its four circumferences are airtightly fixed with a sealant and used as an air filter unit in the semiconductor industry.
It is used as an air filter for air purification during the manufacture of MOS Dynamic RAM. In this case, 99.999% or more of particles of 0.3 μm or larger are collected, and the pressure loss is 25 mmAq or less at the rated value (610 x 610
×150mm). (Problem to be solved by the invention) In recent years, production technology in the semiconductor industry has made remarkable progress. Wafer diameters have become larger, pattern density has become finer, and integration has increased in capacity. For dynamic RAM, 1Mbit~
High integration of 4Mbit is progressing, and the pattern size is 0.5 ~
It has become ultra-fine to 1.5 μm, and therefore the particles to be removed by paper are extremely fine, 0.1 to 0.05 μm. Air filter paper with low pressure loss and high collection efficiency is desired, but the particle size is still 0.05 μm. μm particles
There is no existing paper that can collect 99.999% of these substances, and its realization is desired. (Means for solving the problems) The present invention provides fine particle diameters that could not be realized conventionally.
We provide glass fiber paper for ultra-high performance air filters that can collect 0.05 μm particles with low pressure loss and a high collection rate of 99.999%.
Less than 2-3% by weight of glass fiber and fiber diameter of 0.05-
It consists of a blend of 5-15% by weight of glass fibers of 0.2 μm and 93-82% by weight of glass fibers of different fiber diameters. (Function) 2 to 3% by weight of glass fibers having a fiber diameter of less than 0.05 μm and a fiber diameter of 0.05 to 0.2 μm, which are the characteristics of the present invention described above.
For example, when using a glass fiber paper made by blending 5 to 15% by weight of glass fibers with a diameter of 5 to 15 mm and 93 to 82% by weight of glass fibers with a different fiber diameter, for example, when used as an air filter unit incorporating this paper, it is different from that of conventional paper. Compared to an air filter unit incorporating a filter, it is possible to collect 99.999% of particles with a particle size of 0.05 μm with a pressure drop of 25 mmAq (0.7 m/s) as low as below. (Example) An example of the present invention will be described below. Conventional short glass fiber manufacturing equipment produces glass fibers with various blending compositions having different fiber diameters, but the present invention is particularly capable of producing glass fiber sets having various blending compositions with different fiber diameters. By mixing various samples and making paper-making paper patterns, we use them especially as an air filter unit, and in particular, we can collect 99.999% of particles with a particle size of 0.05 μm, while the pressure loss is as low as 25 mmAq or less. We conducted various tests and research to obtain the desired product, and as a result, we found that the paper contains 2 to 3% by weight of glass fibers with a fiber diameter of less than 0.05 μm, and 5 to 15% by weight of glass fibers with a fiber diameter of 0.05 to 0.2 μm. By blending the fibers with glass fibers of other fiber diameters so as to include the above-mentioned fibers and making paper, preferably having a thickness of 0.3 to 0.50 mm and a basis weight of 60 to 85 g/m ² , this paper is used as a built-in filter unit. In this case, we have achieved a paper that can capture 99.999% of 0.05 μm fine particles under the above-mentioned low pressure drop. Next, detailed examples will be described. Example 1 Glass fiber group A and glass fiber B having the following fiber diameter distribution compositions were produced using a conventional glass fiber manufacturing device.
A set was manufactured.

【table】

[Table] 25% by weight of the above Group A glass fibers (containing 45% by weight of glass fibers with a fiber diameter of 0.05 to 0.2 μm) and 3% of Group B glass fibers (containing 45% by weight of glass fibers with a fiber diameter of 0.05 to 0.2 μm)
65% by weight of 65% by weight (containing 65% by weight) and 10% by weight of long glass fibers (chopped strands) having a fiber diameter of 7 μm were added to a pulper so that the fiber concentration was 0.35%, mixed and disintegrated, and this was made into paper. The obtained wet paper was dried, coated with a mixture of acrylic resin and water repellent, and dried to give a paper weight of 75 g/m ² and a thickness of 0.40.
mm glass fiber paper was obtained. The fiber diameter distribution composition of the paper is as follows.

[Table] The water used for papermaking may be water adjusted to pH 3 with an acid, or neutral water with a pH of 6.8 without the addition of an acid and a trace amount of water, such as
Any of those prepared by adding 8 PPM of cationic polymer may be used. Example 2 57% by weight of Group C glass fibers having the following fiber diameter distribution, which were manufactured separately from 33% by weight of Group A glass fibers, and 10% by weight of chopped strand glass fibers, which are long fibers with a fiber diameter of 7 μm, were used. The fibers were put into a pulper to have a fiber concentration of 0.35%, mixed and disintegrated, and then made into paper in the same manner as in Example 1, with a basis weight of 85 g/m ² and a thickness of
A 0.45 mm paper was obtained. The fiber diameter distribution composition of the paper is as follows.

【table】

[Table] Comparative example: Fabric weight made in the same manner as in Example 1 by blending 90% by weight of short glass fibers with a fiber diameter of 0.3 to 4 μm and 10% by weight of long glass fibers (chopped strands) with a fiber diameter of 7 μm. A conventional paper with a weight of 75 g/m ² and a thickness of 0.40 mm was prepared. The paper of Examples 1 and 2 of the present invention and the paper of Comparative Example were tested for the filter characteristics of the paper itself that was not incorporated into the air filter unit, and the air filter characteristics of the paper that was incorporated into the air filter unit. The results were as shown in Table 1 below. All air filter unit dimensions are 610
×610×150mm.

[Table] As is clear from Table 1 above, fiber diameter is 0.05μm
Less than 2-3% by weight of short glass fibers and a fiber diameter of 0.05
When using the paper of the present invention containing 5 to 15% by weight of short glass fibers of ~0.2 μm as an air filter, 99.999% of fine particles with a particle size of 0.05 μm and 25 mm Aq.
(at 0.7m/s) can be collected with low pressure loss of less than
It is recognized that it can be applied to ultra-high performance air filters. As a result of many experimental studies, fiber diameter 0.05~
If the content of short glass fibers of 0.2 μm is less than 5%, the above-mentioned high collection efficiency cannot be maintained, while if it exceeds 15%, the pressure loss increases and becomes impractical. In addition, the content of glass fibers with a fiber diameter of less than 0.05 μm is
Although an increase of up to a few percent is fine, it was found that an increase beyond that was not effective in increasing the collection efficiency of 0.05 μDOP. The remainder of the paper has a fiber diameter of 0.2μm.
The above effect can be achieved by constructing fibers with arbitrary short fibers selected from up to 9 μm in diameter, but in order to increase the zigzag bending strength,
~9μm chopped strand (long glass fiber)
It is preferable to contain. In addition, the weight of the paper of the present invention is 60 to 85 g/m ² and the thickness
Practically preferred is 0.3 to 0.5 mm. In addition, extremely fine short fibers with a fiber diameter of less than 0.05 μm and fiber diameters of 0.05 to 0.2 μm easily come out of the papermaking net during papermaking. This can prevent it from becoming shorter. (Effects of the Invention) The glass fiber paper of the present invention contains 2 to 3% by weight of glass fibers with a fiber diameter of less than 0.05 μm and a fiber diameter of 0.05 to 3% by weight.
It consists of a blend of 5-15% by weight of 0.2 μm glass fibers and 93-82% by weight of glass fibers with different fiber diameters, so it has a particle size that could not be achieved conventionally.
It has filter properties that can collect 99.999% of particles of 0.05 μm with low pressure loss, and has the effect of providing excellent performance as an ultra-high performance air filter unit in the electronic industry.

Claims (1)

[Claims] 1. 2 to 3% by weight of glass fibers with a fiber diameter of less than 0.05 μm, 5 to 15% by weight of glass fibers with a fiber diameter of 0.05 to 0.2 μm, and 93 to 93% of glass fibers with different fiber diameters.
Ultra-high performance glass fiber paper for air filters made of 82% by weight. 2. The paper according to claim 1, which has a thickness of 0.3 to 0.5 mm and a basis weight of 60 to 85 g/ ^m2 .