The present invention provides an intermediate film for laminated glass which can improve sound insulation. The intermediate film has a layered structure including at least two layers, comprising: a first layer containing a polyvinyl acetal resin and a plasticizer; and a second layer positioned on a first surface of the first layer. In a phase diagram of three values including a degree of acetalization, a degree of acetylation, and a hydroxyl group content of the polyvinyl acetal resin contained in the first layer, the values of the degree of acetalization, the degree of acetylation, and the hydroxyl group content each fall within a region surrounded by a line including four straight lines connecting first, second, third, and fourth coordinates, which respectively have a degree of acetalization:degree of acetylation:hydroxyl group content of 70 mol %:30 mol %:0 mol %, 34 mol %:30 mol %:36 mol %, 94 mol %:0 mol %:6 mol %, and 100 mol %:0 mol %:0 mol %.

The present invention provides an intermediate film for laminated glass which can improve sound insulation. The intermediate film has a layered structure including at least two layers, comprising: a first layer containing a polyvinyl acetal resin and a plasticizer; and a second layer positioned on a first surface of the first layer. In a phase diagram of three values including a degree of acetalization, a degree of acetylation, and a hydroxyl group content of the polyvinyl acetal resin contained in the first layer, the values of the degree of acetalization, the degree of acetylation, and the hydroxyl group content each fall within a region surrounded by a line including four straight lines connecting first, second, third, and fourth coordinates, which respectively have a degree of acetalization:degree of acetylation:hydroxyl group content of 70 mol %:30 mol %:0 mol %, 34 mol %:30 mol %:36 mol %, 94 mol %:0 mol %:6 mol %, and 100 mol %:0 mol %:0 mol %.

A method and a PVB cleaning and/or upgrading system for cleaning and upgrading post-consumer and/or post-industrial polyvinyl butyral is provided. The system includes an extraction station for extraction with liquid or supercritical carbon dioxide. The extraction station comprises a sealable container with means for introducing pressurized liquid carbon dioxide into the container and means for stirring PVB material. The station further includes transfer means for transferring the pressurized liquid carbon dioxide containing extracted plasticizer and/or contaminants from the container to a distillation unit. The distillation unit separates extracted plasticizer and/or contaminants from the carbon dioxide, by evaporation of the liquefied CO2. The system further includes pressurizing means, such as a compressor, for pressurizing and liquefying of the CO2 evaporated in the distillation unit.

A method and a PVB cleaning and/or upgrading system for cleaning and upgrading post-consumer and/or post-industrial polyvinyl butyral is provided. The system includes an extraction station for extraction with liquid or supercritical carbon dioxide. The extraction station comprises a sealable container with means for introducing pressurized liquid carbon dioxide into the container and means for stirring PVB material. The station further includes transfer means for transferring the pressurized liquid carbon dioxide containing extracted plasticizer and/or contaminants from the container to a distillation unit. The distillation unit separates extracted plasticizer and/or contaminants from the carbon dioxide, by evaporation of the liquefied CO2. The system further includes pressurizing means, such as a compressor, for pressurizing and liquefying of the CO2 evaporated in the distillation unit.

The present invention relates to resin particles including a residue unit represented by the following general formula (1) and having a volume average particle diameter equal to or more than 5 m and equal to or less than 2000 m, and a method for producing thereof. Furthermore the present invention relates to a fluororesin comprising a residue unit represented by a general formula (1) and having a weight average molecular weight Mw in a range of 510.sup.4 to 310.sup.5, and a yellow index of a heat-melted molded product (thickness 3 mm) after 24 h at 280 C. of equal to or less than 6, and a method for producing thereof.

##STR00001##

In the formula (1), Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 are each independently one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, or a cyclic perfluoroalkyl group having 3 to 7 carbon atoms. The perfluoroalkyl group may have an ethereal oxygen atom. Further, Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 may be linked to one another to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom.

The present invention relates to resin particles including a residue unit represented by the following general formula (1) and having a volume average particle diameter equal to or more than 5 m and equal to or less than 2000 m, and a method for producing thereof. Furthermore the present invention relates to a fluororesin comprising a residue unit represented by a general formula (1) and having a weight average molecular weight Mw in a range of 510.sup.4 to 310.sup.5, and a yellow index of a heat-melted molded product (thickness 3 mm) after 24 h at 280 C. of equal to or less than 6, and a method for producing thereof.

##STR00001##

In the formula (1), Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 are each independently one of the groups consisting of a fluorine atom, a linear perfluoroalkyl group having 1 to 7 carbon atoms, a branched perfluoroalkyl group having 3 to 7 carbon atoms, or a cyclic perfluoroalkyl group having 3 to 7 carbon atoms. The perfluoroalkyl group may have an ethereal oxygen atom. Further, Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 may be linked to one another to form a ring having 4 or more and 8 or less carbon atoms, and the ring may include an ethereal oxygen atom.

A polyvinyl acetal resin composition includes a polyvinyl acetal, an aldehyde, and an alkanol, wherein the alkanol is present in an amount of 50 parts by weight or more with respect to 100 parts by weight of the aldehyde.

A polyvinyl acetal resin composition includes a polyvinyl acetal, an aldehyde, and an alkanol, wherein the alkanol is present in an amount of 50 parts by weight or more with respect to 100 parts by weight of the aldehyde.

A fluororesin that includes a residue unit represented by formula (1), and a terminal group represented by formula (2); and a fluororesin that includes a residue unit represented by formula (1) and has a transmittance of 50% or more measured at an optical path length of 10 mm and a wavelength of 275 nm when dissolved in perfluorohexane to produce a 10 wt % perfluorohexane solution. In formula (1): Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 each independently represent one selected from the group consisting of fluorine atoms, C1-7 linear perfluoroalkyl groups, C3-7 branched perfluoroalkyl groups, or C3-7 cyclic perfluoroalkyl groups; the perfluoroalkyl groups may have an etheric oxygen atom; Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 may bond to each other to form a ring having 4 to 8 carbon atoms; and the ring may include an etheric oxygen atom. In formula (2), i is an integer of 3-20.

##STR00001##

##STR00002##

A fluororesin that includes a residue unit represented by formula (1), and a terminal group represented by formula (2); and a fluororesin that includes a residue unit represented by formula (1) and has a transmittance of 50% or more measured at an optical path length of 10 mm and a wavelength of 275 nm when dissolved in perfluorohexane to produce a 10 wt % perfluorohexane solution. In formula (1): Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 each independently represent one selected from the group consisting of fluorine atoms, C1-7 linear perfluoroalkyl groups, C3-7 branched perfluoroalkyl groups, or C3-7 cyclic perfluoroalkyl groups; the perfluoroalkyl groups may have an etheric oxygen atom; Rf.sub.1, Rf.sub.2, Rf.sub.3, and Rf.sub.4 may bond to each other to form a ring having 4 to 8 carbon atoms; and the ring may include an etheric oxygen atom. In formula (2), i is an integer of 3-20.

##STR00001##

##STR00002##