Filter medium and structure

A liquid filtration medium comprising a thermally bonded sheet, the sheet comprising:

• (a) about 10 to 90 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• (b) about 10 to 90 wt % of a media fiber having a fiber diameter of about 0.1 to 5 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a thickness of about 0.1 to 2 mm, a solidity of about 2 to 25%, a basis weight of about 2 to 200 g-m−2, a pore size of about 0.2 to 50 micrometers and a permeability of about 2 to 200 ft-min−1.

A method of filtering a liquid stream, the method comprising:

• (a) placing a filter unit into the stream and
• (b) retaining particulate entrained in the filter in the stream using filter media within the filter unit, the filter media comprising a thermally bonded sheet comprising:
• (i) about 10 to 90 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• (ii) about 10 to 90 wt % of a media fiber having a fiber diameter of about 0.1 to 5 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the medium has a thickness of about 0.1 to 2 mm, a solidity of about 2 to 25%, a basis weight of about 2 to 200 g-m−2, a pore size of about 0.2 to 50 micrometers and a permeability of about 2 to 200 ft-min−1.

A filtration medium for filtering a lubricant oil comprising a thermally bonded sheet, the sheet comprising:

• (a) about 1 to 40 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 15 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• (b) about 60 to 99 wt % of a glass fiber having a fiber diameter of about 0.1 to 5 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a thickness of about 0.2 to 2 mm, a solidity of about 2 to 10%, a basis weight of about 10 to 50 g-m−2, a pore size of about 0.5 to 10 micrometers and a permeability of about 0.1 to 30 ft-min−1.

A filtration medium for filtering a hydraulic oil comprising a thermally bonded sheet, the sheet comprising:

• (a) about 20 to 80 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 15 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• (b) about 80 to 20 wt % of a media fiber having a fiber diameter of about 0.1 to 2 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a thickness of about 0.2 to 2 mm, a basis weight of about 40 to 350 g-m−2, a pore size of about 0.5 to 30 micrometers and a permeability of about 5 to 200 ft-min−1.

A method of filtering a heated fluid, the method comprises the steps of:

• (a) passing a mobile fluid phase containing a contaminant through a filter medium, the medium having a thickness of about 0.2 to 50 mm, the medium comprising a thermally bonded sheet, the sheet comprising:
• (i) about 20 to 80 wt % of a bicomponent binder fiber having a first component with a melting point and a second component with a lower melting point, the fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• (ii) about 20 to 80 wt % of a glass fiber having a fiber diameter of about 0.1 to 30 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a solidity of about 2 to 25%, a basis weight of about 10 to 1000 g-m−2, a pore size of about 0.5 to 100 micrometers and a permeability of about 5 to 500 ft-min−1, the mobile fluid phase having a temperature greater than the melting point of the second component;
• and
• (b) removing the contaminant.

A filtration medium comprising a thermally bonded sheet, the sheet comprising:

• (a) about 20 to 80 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm:
• (b) an effective medium bonding amount of a secondary binder fiber, the fiber comprising a thermoplastic resin;
• and
• (c) about 20 to 80 wt % of a glass fiber having a fiber diameter of about 0.1 to 30 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a thickness of about 0.2 to 50 mm, a solidity of about 2 to 25%, a basis weight of about 10 to 1000 g-m−2, a pore size of about 0.5 to 100 micrometers and a permeability of about 5 to 500 ft-min−1.

A liquid filtration medium comprising a thermally bonded sheet, the sheet substantially free of a residue from an aqueous binder resin, the sheet comprising:

• (a) about 10 to 90 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm;
• (b) an effective medium binding amount of a secondary binder fiber, the fiber comprising a thermoplastic resin;
• and
• (c) about 10 to 90 wt % of a media fiber having a fiber diameter of about 0.1 to 5 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a thickness of about 0.1 to 2 mm, a solidity of about 2 to 25%, a basis weight of about 2 to 200 g-m−2, a pore size of about 0.2 to 50 micrometers and a permeability of about 1 to 200 ft-min−1.

A gaseous filtration medium for removing mist from air comprising a thermally bonded sheet, the sheet substantially free of a residue from an aqueous binder resin, the sheet comprising:

• (a) about 20 to 80 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm;
• (b) an effective medium bonding amount of a secondary binder fiber, the fiber comprising a thermoplastic resin;
• and
• (c) about 20 to 80 wt % of a media fiber with a diameter of about 0.1 to 20 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a thickness of about 0.1 to 2 mm, a solidity of about 2 to 25%, a basis weight of about 20 to 200 g-m−2, a pore size of about 5 to 20 micrometers and a permeability of about 5 to 500 ft-min−1.

A gaseous filtration medium for removing particulate from air comprising a thermally bonded sheet, the sheet substantially free of a residue from an aqueous binder resin, the sheet comprising:

• (a) about 80 to 98 wt % of a bicomponent binder fiber having a fiber diameter of about 10 to 15 micrometers and a fiber length of about 0.1 to 15cm;
• (b) an effective medium bonding amount of a secondary binder fiber, the fiber comprising a thermoplastic resin;
• and
• (c) about 2 to 20 wt % of a media fiber with a diameter of about 0.1 to 5 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the media has a thickness of about 0.1 to 2 mm, a solidity of about 10 to 25%, a basis weight of about 40 to 400 g-m−2, a pore size of about 10 to 30 micrometers and a permeability of about 20 to 200 ft-min−1.

A method of filtering a liquid stream, the method comprising:

• placing a filter unit into the stream;
• and
• retaining particulate entrained in the filter in the stream using filter medium within the filter unit, the filter medium comprising a thermally bonded sheet comprising:
• about 10 to 40 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• about 60 to 90 wt % of a fiber comprising glass fiber and having a fiber diameter of about 0.1 to 5 micrometers and an aspect ratio of about 10 to 10,000;
• and
• about 0.1 to 25 wt % of a binder resin,
• wherein the filter medium has a thickness of about 0.1 to 2 mm, a solidity of about 2 to 25%, a basis weight of about 2 to 200 g/m2, a pore size of about 0.2 to 30 micrometers and a permeability of about 2 to 200 ft/min.

A method of filtering a heated gaseous stream to remove a contaminant, the method comprising:

• placing a filter unit into the stream;
• and
• retaining particulate entrained in the filter in the stream using filter medium within the filter unit, the filter medium comprising a thermally bonded sheet comprising:
• about 20 to 80 wt % of a bicomponent binder fiber having a first component with a melting point and a second component with a lower melting point, the fiber having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• about 20 to 80 wt % of a fiber comprising glass fiber and having a fiber diameter of about 0.1 to 20 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the heated gaseous stream has a temperature greater than the melting point of the second component of the bicomponent fiber, and
• wherein the filter medium has a thickness of about 0.2 to 2 mm, a solidity of about 2 to 25%, a basis weight of about 40 to 350 g/m2, a pore size of about 0.5 to 30 micrometers and a permeability of about 5 to 200 ft/min.

A method of filtering a liquid stream, the method comprising:

• placing a filter unit into the liquid stream, the liquid stream comprising a fuel, a lubricant oil, or a hydraulic fluid;
• and
• retaining particulate entrained in the filter in the stream using filter medium within the filter unit, the filter medium comprising a thermally bonded sheet comprising:
• about 1 to 40 wt % of a bicomponent binder fiber having a fiber diameter of about 5 to 15 micrometers and a fiber length of about 0.1 to 15 cm;
• and
• about 60 to 90 wt % of a glass fiber having a fiber diameter of about 0.1 to 5 micrometers and an aspect ratio of about 10 to 10,000;
• wherein the filter medium has a thickness of about 0.2 to 2 mm, a solidity of about 2 to 10%, a basis weight of about 10 to 50 g/m2, a pore size of about 0.5 to 10 micrometers and a permeability of about 2 to 30 ft/min.