Daikin Industries, Ltd.

Kunihiko Inui

Yoshiyuki Shibuya

Hideyuki Kiyotani

Taku Yamanaka

Shinichi Chaen

Shunji Kasai

Makoto Kobayashi

Hitoshi Niinuma

Tatsumi Sakano

Li Bao

Osamu Tanaka

Seigo Yamamoto

Makoto Ono

Yasuhiko Sawada

Satoshi Hara

Osamu Inoue

Masahiko Yamada

Nobuki Uraoka

Tomohisa Konishi

Kohei Yasuda

Emi Kiritani

A tetrafluoroethylene polymer is provided in an air filter medium having a pressure loss that can be reduced and made uniform at a plurality of positions. The tetrafluoroethylene polymer may also be provided in an air filter medium, a filter pack, or an air filter unit. The tetrafluoroethylene polymer has drawability and non-melt processability. The tetrafluoroethylene polymer has a ratio S/Sof 0.60 or more, where Srepresents an endotherm mJ/mg in a range of T° C. or higher and 350° C. or lower, T° C. is a temperature 2.5° C. lower than a temperature T° C. (340≤T≤345) at which a minimum point is given on a heat-of-fusion curve obtained by measuring an unbaked polymer for measurement having no history of heating to a temperature of 300° C. or higher using a differential scanning calorimeter at a temperature-increasing rate of 2° C./min, and Srepresents an endotherm mJ/mg in a range of 320° C. or higher and T° C. or lower.

Tetrafluoroethylene polymer, air filter medium, filter pack, and air filter unit

An air filter medium reduces a decrease in collection efficiency in the case where a main collection layer and a pre-collection layer having a lower collection efficiency than the main collection layer are used. An air filter medium that collects dust in gas includes a main collection layer and a pre-collection layer that has a lower collection efficiency of NaCl particles having a particle size of 0.3 &#x3bc;m than the main collection layer, is disposed on an upstream side of an air flow with respect to the main collection layer, and has water repellency.

Air filter medium

The present invention provides a porous body having high strength, a small pore size, and excellent homogeneity. The porous body of the present invention includes polytetrafluoroethylene and has a microstructure that includes nodes and fibrils. The microstructure further includes, in addition to the nodes and the fibrils, fused points where a fibril that links two nodes and another fibril that links another two nodes are fused with each other.

Porous body, polymer electrolyte membrane, filter material for filter, and filter unit

A filter medium for an air filter includes a pre-collection member, a first porous film, and a second porous film arranged in order from the side that is upstream of the air current. Each of the first porous film and the second porous film has a pressure loss of 30 Pa or more and 90 Pa or less when air is passed through each porous film at a flow rate of 5.3 cm/s, and has a collection efficiency of 95% or more and 99.9% or less for NaCl particles having a particle diameter of 0.3 &#x3bc;m when air containing the NaCl particles is passed through each of the porous films at a flow rate of 5.3 cm/s. The pre-collection member has a pressure loss of 5 Pa or more and less than 55 Pa when air is passed through the pre-collection member at a flow rate of 5.3 cm/s, has a collection efficiency of 15% or more and less than 85% for NaCl particles having a particle diameter of 0.3 &#x3bc;m when air containing the NaCl particles is passed through the pre-collection member at a flow rate of 5.3 cm/s, and has a thickness of more than 0.4 mm.

Filter medium for air filter, filter pack, air filter unit and method for producing the filter medium for air filter

A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 &#x3bc;m when air containing the particles is passed through at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be in a filter pack or filter unit, and produced by integrating the films and the pre-collection member using heat lamination.

Filter medium for air filter, filter pack, air filter unit, and method for producing filter medium for air filter

A filtering medium includes first and second porous membranes mainly composed of fluororesin, and a plurality of air permeable supports to support the first and second membranes. The second membrane is disposed downstream of the first membrane. When air containing polyalphaolefin particles with a count median diameter of 0.25 &#x3bc;m is continuously passed through at a flow rate of 5.3 cm/sec and pressure loss is increased by 250 Pa, the first membrane has a dust retention amount larger than the second membrane. The filtering medium has a pressure loss of less than 200 Pa when air is passed through at a flow rate of 5.3 cm/sec. A collecting efficiency of NaCl particles with a particle diameter of 0.3 &#x3bc;m is 99.97% or more when air containing the NaCl particles is passed through at a flow rate of 5.3 cm/sec. The dust retention amount is 25 g/mor more.

Filtering medium for air filter, filter pack, air filter unit, and method for producing filtering medium for air filter

A mixed powder and a material for molding have polytetrafluoroethylene as a main component. Each includes polytetrafluoroethylene that can be fibrillated, a non-hot melt processable component that is not fibrillated, and a hot melt processable component with a melting point of lower than 320&#xb0; C. that is not fibrillated. The non-hot melt processable component that is not fibrillated is contained in a range of 20 to 40% by weight of the total weight. The hot melt processable component is contained at equal to or more than 0.1% by weight but less than 20% by weight of the total weight. A drawn porous body includes a plurality of fibrils, and a plurality of knotted portions that are connected to each other by the fibrils.

Mixed powder and material for molding having PTFE as main component, and drawn porous body

An embossed air filter filtration medium has at least one porous film and a plurality of air-permeable support materials supporting the at least one porous film. The least one porous film includes a fibril-formable polytetrafluoroethylene, a non-fibril-forming and non-hot-melt-processable component, and a non-fibril-forming and hot-melt-processable component having a melting point below 320&#xb0; C. Surfaces of both sides of the air filter filtration medium are formed by two air-permeable support materials of the air-permeable support materials. The air filter filtration medium has a plurality of embossed projections. The embossed air filter filtration medium may be part of a filter pack, which may be part of an air filter unit. The embossed air filter filtration medium is manufactured by laminating air-permeable support materials on the at least one porous film and embossing the air filter filtration medium to form the projections.

Embossed air filter filtration medium, filter pack, air filter unit, and method for manufacturing filtration medium for embossed air filter

A filter medium includes first and second porous films mainly containing fluororesin, and a pre-collection member upstream of the first film. The second film is downstream of the first film. The pre-collection member has a pressure drop when air is passed through at a flow rate of 5.3 cm/s of between 15 Pa and 55 Pa, a collection efficiency of NaCl particles having a particle diameter of 0.3 &#x3bc;m when air containing the particles is passed hrough at a flow rate of 5.3 cm/s of between 25% and 80%, a thickness of 0.4 mm or less, and a PF value between 7 and 15. The PF value={&#x2212;log((100&#x2212;collection efficiency (%))/100)}/(pressure drop (Pa)/1000). A ratio of the PF value of the pre-collection member to the PF value when the first and second films are overlapped, is between 0.20 and 0.45. The filter medium can be used in a filter pack or filter unit, and may be produced by integrating the first and second films and the pre-collection member using heat lamination.

A composition, a mixed powder and a material for molding have polytetrafluoroethylene as a main component. Each includes polytetrafluoroethylene that can be fibrillated, a non-hot melt processable component that is not fibrillated, and a hot melt processable component with a melting point of lower than 320&#xb0; C. that is not fibrillated. The hot melt processable component is contained at equal to or more than 0.1% by weight but less than 20% by weight of a total weight. A filtering medium for an air filter includes a porous membrane made of these components, and an air permeable support. The porous membrane is manufactured, by mixing these components, extruding the mixture, rolling and drawing.

Composition having PTFE as main component, mixed powder, material for molding, filtering medium for filter, air filter unit, and a method for manufacturing a porous membrane

A filter medium includes a porous film and a support material supporting the porous film. The porous film includes polytetrafluoroethylene, has an average pore diameter of at least 2.5 &#x3bc;m, and has a porosity of at least 95%. A pressure loss is less than 100 Pa when air is passed through the filter medium at a velocity of 5.3 cm/sec. A collection efficiency of NaCl particles is at least 95% when air including NaCl particles with a particle diameter of 0.3 &#x3bc;m is passed through the filter medium at a velocity of 5.3 cm/sec. A PF value is at least 30, where PF={&#x2212;log [(100&#x2212;collection efficiency (%))/100]/pressure loss (Pa)}&#xd7;1000. A dust holding capacity of polyalphaolefin particles held in the filter medium is at least 15 g/mwhen air including polyalphaolefin particles with a count median diameter of 0.25 &#x3bc;m is continuously passed through the filter medium at a velocity of 5.3 cm/sec and pressure loss reaches 300 Pa.

Filter medium equipped with porous film, method of manufacturing same, filter pack, and filter unit

Provided is a material that can be easily biaxially oriented, homogeneously stretched even with a high draw ratio, and formed into a PTFE porous membrane with low pressure loss. The present invention relates to a polytetrafluoroethylene mixture comprising: a fibrillable modified polytetrafluoroethylene; and a fibrillable polytetrafluoroethylene homopolymer, the polytetrafluoroethylene homopolymer having strength at break of 25 N or higher.

Polytetrafluoroethylene mixture

Provided is a material that can be easily biaxially oriented, homogeneously stretched even with a high draw ratio, and formed into a polytetrafluoroethylene porous membrane with low pressure loss. The present invention relates to a polytetrafluoroethylene mixture comprising: a modified polytetrafluoroethylene; and a fibrillable polytetrafluoroethylene homopolymer, the modified polytetrafluoroethylene having an extrusion pressure to a cylinder, at a reduction ratio of 1600, of 70 MPa or higher.

A method of manufacturing a filter medium that has a PF value that exceeds 32, the PF value calculated from the pressure loss and the collection efficiency of the filter medium according to the following formula:PF=[&#x2212;log(permeability (%)/100)/(pressure loss (Pa)]&#xd7;1000[Formula 1]in which permeability (%)=100&#x2212;collection efficiency (%). In this method, 380 ml or more of a liquid lubricant at 20&#xb0; C. is added per 1 kg of a PTFE fine powder, this compound is processed into a tape shape and elongated to obtain a PTFE porous film, and an air permeable support member is heat laminated to at least one surface of the PTFE porous film.

Method for preparing filtering material

An air filter medium is provided with a porous film made from a polytetafluoroethylene, and a non-woven fabric laminated on at least one side of the porous film. The non-woven fabric has an apparent density satisfying the following equation: apparent density (g/cm )<1.5&times;(basis weight (g/m )/1000)&plus;0.11. The filter medium is produced by a process that includes a first step of producing a porous film formed from a polytetrafluoroethylene, and a second step of laminating a non-woven fabric on at least one side of the porous film on heating roll that has undergone a non-adhesive treatment. The filter medium is used to manufacture an air filter pack, while the air filter pack is used to manufacture an air filter unit.

Growing community of inventors

Settsu, Japan

Kunihiko Inui