The present disclosure relates to an optical laminate for a head-up display, including (A) at least one polyvinyl acetal resin layer having a photoelastic coefficient (PeA) in the range of the following Expression (1) and (B) at least one optical functional layer. Further, the present disclosure relates to functional glass for a head-up display including the optical laminate. and a head-up display including: the optical laminate or the functional glass.

[00001]$\left|\text{PeA}\right|\le 4.0\times {10}^{-11}{\text{Pa}}^{-1}\mathrm{...}\text{(1)}$

The present disclosure relates to an optical laminate for a head-up display, including (A) at least one polyvinyl acetal resin layer having a photoelastic coefficient (PeA) in the range of the following Expression (1) and (B) at least one optical functional layer. Further, the present disclosure relates to functional glass for a head-up display including the optical laminate. and a head-up display including: the optical laminate or the functional glass.

[00001]$\left|\text{PeA}\right|\le 4.0\times {10}^{-11}{\text{Pa}}^{-1}\mathrm{...}\text{(1)}$

Compounds of formula III:

##STR00001##

and salts thereof are disclosed. Also disclosed are methods for preparing compounds of formula III, intermediates useful for preparing compounds of formula III and methods for preparing compounds and materials from compounds of formula III.

Compounds of formula III:

##STR00001##

and salts thereof are disclosed. Also disclosed are methods for preparing compounds of formula III, intermediates useful for preparing compounds of formula III and methods for preparing compounds and materials from compounds of formula III.

An object of the present disclosure is to provide a method for producing a fluorine-containing polymer and a composition containing the fluorine-containing polymer.

The present disclosure provides a composition comprising (A) a fluorine-containing polymer comprising as a main component a structural unit containing a fluorine-containing aliphatic ring, and (B) an aprotic solvent, wherein the fluorine-containing aliphatic ring of the fluorine-containing polymer (A) contains one, two, or three etheric oxygen atoms as a ring-constituting atom; when the fluorine-containing aliphatic ring contains a plurality of etheric oxygen atoms, the etheric oxygen atoms are not adjacent to each other; and the fluorine-containing polymer (A) is present in an amount of 20 mass % or more based on the mass of the composition.

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 μm and equal to or less than 2000 μm, 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 5×10.sup.4 to 3×10.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 a fluororesin including a residue unit represented by a following general formula (1) and having a haze value equal to or less than 2% of a heat-press molded product (thickness 1 mm) with a small haze value of a melt-molded product and a method for producing the same.

##STR00001##

In the formula (1), Rf.sub.1, Rf.sub.2, Rf.sub.3 and Rf.sub.4 each independently represent 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, and a cyclic perfluoroalkyl group having 3 to 7 carbon atoms, the perfluoroalkyl group may have an ethereal oxygen atom, Rf.sub.1, Rf.sub.2, Rf.sub.3 and Rf.sub.4 may be linked to each other 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 further relates to a method for producing fluororesin particles that each include a fluorine-containing aliphatic ring structure. The method comprises a precipitation step of lowering a solution temperature of a fluororesin (A) solution in which a fluororesin (A) including a fluorine-containing aliphatic ring structure is dissolved in a solvent (B), to precipitate particles of the fluororesin (A). The method is excelling in productivity and making it possible to remove foreign matter.

The present invention relates to a fluororesin including a residue unit represented by a following general formula (1) and having a haze value equal to or less than 2% of a heat-press molded product (thickness 1 mm) with a small haze value of a melt-molded product and a method for producing the same.

##STR00001##

In the formula (1), Rf.sub.1, Rf.sub.2, Rf.sub.3 and Rf.sub.4 each independently represent 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, and a cyclic perfluoroalkyl group having 3 to 7 carbon atoms, the perfluoroalkyl group may have an ethereal oxygen atom, Rf.sub.1, Rf.sub.2, Rf.sub.3 and Rf.sub.4 may be linked to each other 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 further relates to a method for producing fluororesin particles that each include a fluorine-containing aliphatic ring structure. The method comprises a precipitation step of lowering a solution temperature of a fluororesin (A) solution in which a fluororesin (A) including a fluorine-containing aliphatic ring structure is dissolved in a solvent (B), to precipitate particles of the fluororesin (A). The method is excelling in productivity and making it possible to remove foreign matter.

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 μm and equal to or less than 2000 μm, 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 5×10.sup.4 to 3×10.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.

An object of the present disclosure is to provide a film that has high water slidability, and a substrate having a surface covered with the film. The present disclosure provides a film having the properties of a sliding velocity of 150 mm/s or more at an inclination angle of 30° and an average surface roughness (Ra) of 1 μm or less, and further provides a substrate having a surface covered with the film.