FILTER MATERIAL FOR AUTOMATIC TRANSMISSION OIL FILTER

Abstract

Provided is a filter material for an automatic transmission oil filter that has excellent filtration performance and that can trap even dust having a small particle size. The filter material comprises an entangled nonwoven fabric in which fine fibers generated from dividable composite fibers are entangled with each other.

Claims

1. A filter material for an automatic transmission oil filter, said filter material comprising an entangled nonwoven fabric in which fine fibers generated from dividable composite fibers are entangled with each other.

2. The filter material for an automatic transmission oil filter according to claim 1, characterized in that wherein the entangled nonwoven fabric comprises fine fibers having a fineness of 0.4 dtex or less, and air permeability is 30 mL/cm.sup.2/sec. or more.

Description

EXAMPLES

[0054] The present invention now will be further illustrated by, but is by no means limited to, the following Examples.

Example 1

[0055] (1) Preparation of Fibers

[0056] The following fibers were prepared respectively: [0057] (a) dividable composite fibers having a fineness of 2.75 dtex and a fiber length of 51 mm, with an orange-shaped fiber cross section in which polyethylene terephthalate and nylon 6 were arranged alternately (polyethylene terephthalate fine fibers having a fineness of 0.17 dtex with a substantially triangular cross section, and nylon 6 fine fibers having a fineness of 0.17 dtex with a substantially triangular cross section could be generated.); [0058] (b) polyester medium fibers having a fineness of 1.44 dtex and a fiber length of 38 mm made of polyethylene terephthalate; and [0059] (c) polyester thick fibers having a fineness of 6.7 dtex and a fiber length of 76 mm made of polyethylene terephthalate. [0060] (2) Manufacture of Filter Materials

[0061] The prepared fibers were used and mixed with the composition shown in Table 1, and opened using a card machine to form unidirectional fiber webs, and the fiber webs were crossed so that the orientation direction of the fibers intersected the transport direction of the fiber webs to form cross-fiber webs respectively.

[0062] Next, each cross-fiber web was entangled by needle punching at a needle density of 450 needles/cm.sup.2, or entangled with a water jet at a pressure of 10 MPa three times and dried to form each entangled nonwoven fabric.

[0063] After each entangled non-woven fabric was immersed in an epoxy resin bath, it was squeezed between a pair of rolls so that the adhesion amount of epoxy resin was 15 g/m.sup.2 in solid content, and dried at a temperature of 160° C. to produce each filter material.

TABLE-US-00001 TABLE 1 Mass per unit Thickness Fibers area (g/m.sup.2) of filter (mass %) Fi- Res- Filter material (a) (b) (c) bers in material (mm) Comp. Needles 0 70 30 120 15 135 1.1 Ex. 1 Comp. Water jet 0 70 30 120 15 135 1.3 Ex. 2 Example 1 Water jet 10 60 30 120 15 135 1.1 Example 2 Water jet 10 20 70 120 15 135 1.1 Example 3 Water jet 10 20 70 160 15 175 1.3 Example 4 Water jet 30 0 70 140 15 155 1.1 Example 5 Water jet 20 50 30 120 15 135 1.0 Example 6 Water jet 25 25 50 120 15 135 0.9 Example 7 Water jet 30 0 70 120 15 135 1.0 Ref. Ex. Water jet 20 50 30 120 0 120 1.0

[0064] The thickness of filter material is the value under a load of 2 kPa. [0065] (3) Physical Properties of Filter Materials;

[0066] Physical properties of each filter material are shown in Table 2. Each measurement was carried out by the following methods. [0067] (Pore Size)

[0068] The pore size was measured by a mean flow point method using a porometer (Perm Porometer, manufactured by PMI). [0069] (Air Permeability)

[0070] The air permeability was measured by 6.8.1 (a Frazier type method) prescribed in JIS L1913 : 2010 “Test methods for nonwovens”. [0071] (Accumulation Efficiency)

[0072] A tester prescribed in ISO16889 was used to measure the accumulation efficiency under the conditions of a flow rate of 22.7 L/min., an oil volume of 30 L, and a test time of 1 hour. As for the accumulation efficiency, it was judged that the filtration performance was excellent when the concentration decrease rate from the initial dust concentration of 50 mg/L was 60% or more. [0073] (Pressure loss)

[0074] The negative pressure generated at an oil temperature of −20° C. and a flow rate of 8 L/min. was measured. It was judged that the pressure loss was low when the pressure loss was 40 kPa or less. [0075] (Element Moldability)

[0076] The filter material was processed with a fold machine to judge whether the fold shape could be maintained.

TABLE-US-00002 TABLE 2 Amount of Average fineness Pore Air dividable of fibers other Accumulation size permeability composite fibers than fine fibers efficiency Pressure Element (μm) (mL/cm.sup.2/sec) (g/m.sup.2) (dtex) 4 μm loss (kPa) moldability Comp. Ex. 1 40.9 110 0 3.02 39% 9.7 ∘ Comp. Ex. 2 39.1 94 0 3.02 41% 12.1 ∘ Example 1 33.2 72 12 3.19 73% 15.9 ∘ Example 2 36.6 88 12 5.53 63% 12.8 ∘ Example 3 41.2 69 16 5.53 69% 15.8 ∘ Example 4 18.7 34 42 6.70 99% 38.3 ∘ Example 5 21.2 40 24 3.41 93% 32.0 ∘ Example 6 18.5 40 30 4.95 99% 31.3 ∘ Example 7 22.9 40 36 6.70 98% 30.6 ∘ Ref. Ex. 23.8 43 24 3.41 # # x #: Not measured because it could not be molded. [0077] (Results and Discussion) [0078] (1) From the comparison between Comparative Example 1 and Comparative Example 2, the filter material obtained by hydroentanglement has a slightly smaller pore size and becomes denser than the filter material obtained by needle punching, but does not reach sufficient filtration efficiency. [0079] (2) From the comparison between Comparative Example 2 and Example 1, when the filter material contains fine fibers, the pore size of the filter material becomes small, and the filtration efficiency of the filter material is excellent. [0080] (3) From the comparison between Example 1 and Example 2, when the amount of thick fibers in the filter material is large, the pore size of the filter material becomes large, and the filtration efficiency of the filter material becomes poor. [0081] (4) From Examples 1 to 7, when the air permeability of the filter material is 30 mL/cm.sup.2/sec or more, the pressure loss of the filter material is small. In particular, from the comparison between Example 4 and Example 7, when the air permeability of the filter material is 35 mL/cm.sup.2/sec or more, the pressure loss of the filter material becomes smaller. [0082] (5) From the comparison between Example 5 and Referential Example, when the filter material is folded and used, it is preferable to fix fibers with resin. [0083] (6) From the comparison between Example 5 and Example 6, when the amount of dividable composite fibers in the filter material is large, the pore size of the filter material becomes small and the filtration efficiency of the filter material increases. [0084] (7) From Examples 1 to 7, when the pore size of the filter material is 45 μm or less, the filtration efficiency of the filter material is excellent. In particular, from the comparison between Examples 1, 5, and 7, when the pore size of the filter material is 30 μm or less, the filtration efficiency of the filter material is more excellent.

Industrial Applicability

[0085] The filter material of the present invention can be used in the manufacture of an automatic transmission oil filter.

[0086] Although the present invention has been described with reference to specific embodiments, various changes and modifications obvious to those skilled in the art are possible without departing from the scope of the appended claims.