JP2925190B2 - Method for producing filter paper for oil filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial application >> The present invention can increase the specific surface area while keeping the porosity almost constant, and can adsorb and capture submicron-order carbon fine particles generated in engine oil with high efficiency. The present invention relates to a method for producing a filter paper for an oil filter as described above.

<< Background of the Invention >> A filter paper for an oil filter is required to have a long life and high efficiency.

When trying to extend the life of a conventional filter paper mainly composed of natural cellulose fibers used as a material for the filter paper, it is sufficient to reduce the paper layer density and increase the porosity. In this case, the specific surface area of the fiber becomes small, so that the contact area with the carbon fine particles becomes small, and the capture ratio of carbon becomes small.

Conversely, if the density of the paper layer is increased, the specific surface area of the fiber is increased, so that the trapping efficiency is improved.However, since the voids are surely reduced with the increase in the density, the initial oil flow resistance is increased, and the carbon The filter life is shortened because the pressure loss increases in a short time due to the capture.

Therefore, the relationship between the life and the trapping efficiency is a contradictory issue, and only one of the characteristics can be improved at the expense of the other.

An object of the present invention is to solve the above contradictory problems, and an object of the present invention is to provide a method of manufacturing a filter paper for an oil filter, which can improve the capture rate of carbon while maintaining the filter life.

<< Means for Solving the Problems >> In order to achieve the above objects, the present invention provides a method of immersing a base paper made of base paper fibers into a dispersion medium in which fine fibers are dispersed, and applying the base paper to the base paper surface of the base paper. The method includes a step of attaching fine fibers, a step of drying, and a step of impregnating an adhesive to fix the fine fibers attached to the surface of the base material.

<< Operation >> According to the above configuration, the paper layer density can be formed according to the porosity between the base fibers, and the carbon fibers of the order of submicron can be captured by the fine fibers.

<< Embodiment >> Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

First, the manufacturing method of the present invention includes the following steps.

In the papermaking process, the base paper made of the base fiber passed through the drying drum is immersed in a dispersion medium in which fine fibers are well dispersed.

The base paper impregnated with the dispersion medium containing the fine fibers is dried immediately thereafter.

Subsequently, by impregnating the surface of the paper with the phenolic resin resin, the attached fine fibers are fixed on the surface of the base fiber.

FIG. 1 and FIG. 2 are microscopic schematic views of the filter paper formed by the above-described steps, and the base fibers 1 are in a state of being entangled with an appropriate gap 2 between the base fibers 1. Indicates a state in which the fine fibers 3 are randomly attached.

And the contact probability with the carbon fine particles is increased by the specific surface area increased by the layer of the fine fibers 3, and
Over time, the layer of fine fibers 3 holds the carbon inside its volume, so the carbon capture capacity increases.

However, as apparent from the reason described later, although the function is obtained, the gap 2 is sufficiently large, so that the rate of change in the pressure loss rises is significantly different from that of the conventional filter paper having the same paper layer density. The same life can be secured without it.

In the above-described configuration, in order for the fine fibers 3 to exhibit the effect, a raw material mixture for determining the physical properties of the base fiber 1
The factors are the fine fiber diameter and the sticking rate that match the particle size distribution of the carbon fine particles to be captured by the filter paper.

That is, as shown in FIG. 3, the base fiber 1 having a low density of the base paper layer has a small landing area of the fine fiber 3, so that a large amount of fixation cannot be performed, but the rate of change of the specific surface area is large. On the other hand, the base fiber 1 having a high density has a large fixing area because the landing area is large.

However, the sticking rate at which the effect appears is higher than that of the low-density base fiber. Also, in any of the raw material blends, if the fixation rate is too high, the fine fibers 1 agglomerate, and the paper layer space 2
, The effect is reduced.

In consideration of these, when various compositions were changed, the diameter of the base fiber 1 was in the range of 10 to 80 μm, the diameter of the fine fiber 3 was in the range of 0.2 to 1 μm, and the sticking rate was 3 to 30 wt. %, And it has been found that the fiber surface area increases by 15 to 200% while the decrease in the void 2 is only 0.5 to 4% at a fixing rate in this range.

FIG. 4 shows the relationship between the life and the filtration efficiency within the preferred range. When the life L0 is targeted and the efficiency of the conventional filter paper is η1, the filter paper of the present invention is shown by oblique lines. It can be seen that within the preferred range, it is improved to η2.

Further, it is shown that when the efficiency η0 is set as a target, the life of the conventional filter paper is L1 but can be extended to L2.

<< Effects of the Invention >> As described in detail in the above embodiments, in the method for producing a filter paper for an oil filter according to the present invention, a process of merely attaching and fixing fine fibers to a base paper made of a base material is added. Just by doing so, it is possible to form a paper layer density according to the porosity between base fibers, so that fine fibers can capture carbon particles on the order of submicron, and adsorb and capture carbon particles while ensuring long life There is an advantage that the production of a filter paper for an oil filter can be simplified.

[Brief description of the drawings]

FIG. 1 is a microscopic schematic diagram of a filter paper for an oil filter according to the present invention, FIG. 2 is a further enlarged microscopic schematic diagram,
FIG. 3 is a graph showing the relationship between the density of the base material and the fixing rate of the fine fibers, and FIG. 4 is a graph showing the relationship between the life and efficiency of the filter paper according to the present invention. 1 ... substrate 2 ... voids 3 ... fine fibers

Claims (2)

(57) [Claims] 1. A step of immersing a base paper made of paper-made base fibers in a dispersion medium in which fine fibers are dispersed, causing the fine fibers to adhere to the base surface of the base paper, a step of drying, and a step of bonding. Impregnating an agent to fix the fine fibers attached to the surface of the base material. 2. The base fiber has a diameter of 10 to 80 μm,
2. A filter paper for an oil filter according to claim 1, wherein said fine fibers have a diameter of 0.2 to 1 [mu] m, and said fine fibers are fixed in a range of 3 to 30% by weight based on the weight of the substrate. Method.