Abstract: A modified polytetrafluoroethylene which can be formed under a low extrusion pressure and with which changes of the extrusion pressure are suppressed, even in paste extrusion at a high RR ratio, and its production method. The modified polytetrafluoroethylene having units based on tetrafluoroethylene, 0.020 to 0.040 mass % of units based on a monomer represented by the following formula (1), and 0.003 to 0.080 mass % of units based on a monomer represented by the following formula (2), each based on all units of the modified polytetrafluoroethylene. The monomers of formulae (1) and (2) are represented by: CH2?CH—CnF2n+1 (1), wherein n is from 2 to 6; and CF2?CFO(LO)mRf (2), wherein L is a perfluoroalkylene group, Rf is a perfluoroalkyl group, and m is an integer of from 0 to 4.

Abstract: To provide a method for producing an aqueous dispersion of polytetrafluoroethylene, whereby formation of fluorinated oligomers as byproducts is little and CFT of a coating film to be formed is large. A method for producing an aqueous dispersion of polytetrafluoroethylene, which comprises step A1 of polymerizing a non-fluorinated monomer in an aqueous medium to obtain a solution 1 containing a polymer comprising units based on said non-fluorinated monomer, step A2 of conducting polymerization of tetrafluoroethylene in said solution 1 without substantially adding a surfactant to said solution 1, to obtain an aqueous emulsion containing polytetrafluoroethylene particles, and step A3 of adding a nonionic surfactant to said aqueous emulsion, and then concentrating said aqueous emulsion to obtain an aqueous dispersion of polytetrafluoroethylene, wherein the amount of said non-fluorinated monomer used is at most 200 mass ppm to the amount of said tetrafluoroethylene supplied to the polymerization system.

Abstract: To provide a PTFE aqueous dispersion which is excellent in mechanical stability, while being not susceptible to foaming. A polytetrafluoroethylene aqueous dispersion which is characterized by containing from 15 to 70 mass % of PTFE particles having an average primary particle diameter of from 0.1 to 0.5 ?m; from 0.1 to 20,000 ppm, to the PTFE particles, of a fluorinated emulsifier selected from a C4-7 fluorinated carboxylic acid which may have an etheric oxygen atom, and salts of thereof; from 1 to 20 parts by mass, to 100 parts by mass of the PTFE particles, of a nonionic surfactant represented by R1—O-A-H (wherein R1 is a C8-18 alkyl group, and A is a polyoxyalkylene chain); from 0.004 to 0.040 parts by mass, to 100 parts by mass of the PTFE particles, of a polyether polysiloxane copolymer, wherein the polyether chain consists solely of a polyoxypropylene group; and water.

Abstract: To provide a modified PTFE which can be formed under a low extrusion pressure and with which changes of the extrusion pressure are suppressed, even in paste extrusion at a high RR ratio, and its production method. A modified polytetrafluoroethylene having units based on tetrafluoroethylene, units based on a monomer represented by the following formula (1) and units based on a monomer represented by the following formula (2), wherein the content of the units based on the monomer represented by the formula (1) is from 0.020 to 0.040 mass % to all units of the modified polytetrafluoroethylene, and the content of the units based on the monomer represented by the formula (2) is from 0.003 to 0.080 mass % to all units of the modified polytetrafluoroethylene: CH2?CH—CnF2n+1??(1) wherein n is from 2 to 6; CF2?CFO(LO)mRf??(2) wherein L is a perfluoroalkylene group, Rf is a perfluoroalkyl group, and m is an integer of from 0 to 4.

Abstract: To provide a PTFE aqueous dispersion which is excellent in mechanical stability, while being not susceptible to foaming. A polytetrafluoroethylene aqueous dispersion which is characterized by containing from 15 to 70 mass % of PTFE particles having an average primary particle diameter of from 0.1 to 0.5 ?m; from 0.1 to 20,000 ppm, to the PTFE particles, of a fluorinated emulsifier selected from a C4-7 fluorinated carboxylic acid which may have an etheric oxygen atom, and salts of thereof; from 1 to 20 parts by mass, to 100 parts by mass of the PTFE particles, of a nonionic surfactant represented by R1—O-A-H (wherein R1 is a C8-18 alkyl group, and A is a polyoxyalkylene chain); from 0.004 to 0.040 parts by mass, to 100 parts by mass of the PTFE particles, of a polyether polysiloxane copolymer, wherein the polyether chain consists solely of a polyoxypropylene group; and water.

Abstract: To provide a polytetrafluoroethylene aqueous dispersion which is excellent in mechanical stability, while being not susceptible to foaming. The polytetrafluoroethylene aqueous dispersion comprises: 15 to 70 mass % of polytetrafluoroethylene particles having an average primary particle size of 0.1 to 0.5 ?m; 0.1 to 20,000 ppm, to the mass of the polytetrafluoroethylene particles, of a fluorinated emulsifier selected from C4-7 fluorinated carboxylic acids which may have an ether oxygen atom, and salts thereof; 1 to 20 parts by mass, per 100 parts by mass of the PTFE particles, of a nonionic surfactant represented by R1—O-A-H (wherein R1 is a C8-18 alkyl group, and A is a polyoxyalkylene chain); 0.01 to 3.0 parts by mass, per 100 parts by mass of the polytetrafluoroethylene particles, of a compound represented by the formula (2) (wherein R is a C2-4 alkyl group, n is 1 or 2, and each of m1 and m2 is an average repeating number of oxyethylene groups, with (m1+m2) being 1 to 6); and water.

Abstract: To provide a method for producing a tetrafluoroethylene copolymer-containing aqueous dispersion excellent in stability against a mechanical stress.

Abstract: To provide a method for recovering an acid of an anionic fluorinated emulsifier with a high yield from a basic ion exchange resin having a nonionic surfactant physically adsorbed thereon and having the anionic fluorinated emulsifier adsorbed thereon. A method for eluting and recovering an acid of an anionic fluorinated emulsifier from a basic ion exchange resin having a nonionic surfactant physically adsorbed thereon and having the anionic fluorinated emulsifier adsorbed thereon, which comprises a step (1) of bringing the basic ion exchange resin into contact with a water-soluble organic solvent and a step (2) of recovering the acid of the anionic fluorinated emulsifier from the basic ion exchange resin from which the ionic surfactant is eluted in the step (1).

Abstract: To provide a process for producing a PTFE molding powder having a high bulk density from granular polymer particles without using an emulsifying agent having problems of bioaccumulation and toxicity. A process for producing a polytetrafluoroethylene molding powder, which comprises a step of suspension-polymerizing a monomer containing at least 99.8 mass % of tetrafluoroethylene in an aqueous medium to produce granular polymer particles and a step of milling the granular polymer particles, wherein the aqueous medium contains a compound represented by RF(OCF(X1)CF2)k-1OCF(X2)COO?M+, at a concentration of from 0.5 to 2,000 ppm. RF is a perfluorinated C1-10 monovalent organic group, X1 and X2 are fluorine atoms, etc., and M+ is an ammonium ion or the like.

Abstract: To provide a method for recovering an acid of an anionic fluorinated emulsifier with a high yield from a basic ion exchange resin having a nonionic surfactant physically adsorbed thereon and having the anionic fluorinated emulsifier adsorbed thereon. A method for eluting and recovering an acid of an anionic fluorinated emulsifier from a basic ion exchange resin having a nonionic surfactant physically adsorbed thereon and having the anionic fluorinated emulsifier adsorbed thereon, which comprises a step (1) of bringing the basic ion exchange resin into contact with a water-soluble organic solvent and a step (2) of recovering the acid of the anionic fluorinated emulsifier from the basic ion exchange resin from which the ionic surfactant is eluted in the step (1).

Abstract: To provide a process for producing a PTFE molding powder having a high bulk density from granular polymer particles without using an emulsifying agent having problems of bioaccumulation and toxicity. A process for producing a polytetrafluoroethylene molding powder, which comprises a step of suspension-polymerizing a monomer containing at least 99.8 mass % of tetrafluoroethylene in an aqueous medium to produce granular polymer particles and a step of milling the granular polymer particles, wherein the aqueous medium contains a compound represented by RF(OCF(X1)CF2)k-1OCF(X2)COO?M+, at a concentration of from 0.5 to 2,000 ppm. RF is a perfluorinated C1-10 monovalent organic group, X1 and X2 are fluorine atoms, etc., and M+ is an ammonium ion or the like.

Abstract: An outline font dictionary contains outline font data indicative of outlines of characters to be drawn by a drawing output device such as a display device or a printing device. Each of the outlines is divided into a plurality of outline sections which are defined by a plurality of element structures, respectively, formed from the outline font data read out from the outline font dictionary. When the outline font data read out from the outline font dictionary is indicative of continuous outline sections each forming a rectilinear segment, a polygonal line element structure is formed from the read out outline font data. Based on the polygonal line element structure, the continuous outline sections each forming the rectilinear segment are drawn as a polygonal line by the drawing output device.

Abstract: An outline character drawing apparatus comprising a font dictionary, a path forming unit, a rule storage unit and a bit map developing unit. The font dictionary stores a plurality of outline data for geometrically defining character outlines. The path forming unit forms in a common memory a geometrically expressed graphic path by performing such processes as extracting the data corresponding to each character code sent by a client, transforming the data coordinates into an apparatus coordinate system, adjusting the width of stems making up characters, and approximating curve portions by use of broken lines. The outline data include identifiers representing bit map development rules envisaged at the time of defining the characters in question. The rules are used to develop into bit map format the characters expressed in graphic paths. One such rule stipulates that each pixel be located on a lattice point formed by coordinates.