Disclosed herein are delamination resistant glass pharmaceutical containers which may include an aluminosilicate glass having a Class HGA 1 hydrolytic resistance when tested according to ISO 720-1985 testing standard. The glass containers may also have a compressive stress layer with a depth of layer of greater than 25 μm. A surface compressive stress of the glass containers may be greater than or equal to 350 MPa. The delamination resistant glass pharmaceutical containers may be ion exchange strengthened and the ion exchange strengthening may include treating the delamination resistant glass pharmaceutical container in a molten salt bath for a time less than or equal to 5 hours at a temperature less than or equal to 450° C.

A gas separation asymmetric membrane includes a porous layer having gas permeability; and a compact layer having gas separation capability which is formed on the porous layer in which the gas separation asymmetric membrane is formed using a polyimide compound which has a structural unit represented by Formula (I) and at least one structural unit selected from a structural unit represented by Formula (II) or a structural unit represented by Formula (III) and in which the viscosity, at 25° C., of a solution obtained by dissolving the polyimide compound in N-methylpyrrolidone at a concentration of 5% by mass is in a range of 2.2 to 22.0 mPa.Math.sec,

##STR00001##

in the formula, X.sup.1 represents a group having a structure represented by Formula (I-a) or (I-b).

##STR00002##

The present invention provides a tetracarboxylic acid diester compound shown by the following general formula (1),

##STR00001##

wherein X.sub.1 represents a tetravalent organic group; and R.sub.1 represents a group shown by the following general formula (2),

##STR00002##

wherein the dotted line represents a bond; Y.sub.1 represents an organic group with a valency of k+1; “k” represents 1 or 2; and “n” represents 0 or 1. There can be provided a tetracarboxylic acid diester compound that can give a polyimide precursor polymer soluble in a safe organic solvent widely used as a solvent of a composition and usable as a base resin of a photosensitive resin composition.

The present disclosure relates, according to some embodiments, to a multilayered polyimide film comprising a peelable base layer, and a polyimide layer adhered in contact with the peelable base layer. A peelable base layer may be derived from a reaction comprising a diamine compound and a dianhydride compound, wherein the peelable base comprises a polyimide and a structure according to formula (I):

##STR00001##

wherein n is a number of repeating units. According to some embodiments, a quantity of silicon atoms present in a peelable base layer comprises about 1% to about 12% of a total weight of the peelable base layer.

Disclosed is a net-shaped polyimide sponge. The polyimide sponge has a stack structure of nets. Also disclosed is a method for producing a polyimide sponge. The method enables the production of a polyimide sponge in a continuous process, which offers advantages for large-scale production compared to conventional methods using batch systems.

Copoly(imide oxetane) materials are disclosed that can exhibit a low surface energy while possessing the mechanical, thermal, chemical and optical properties associated with polyimides. The copoly(imide oxetane)s are prepared using a minor amount of fluorinated oxetane-derived oligomer with sufficient fluorine-containing segments of the copoly(imide oxetane)s that migrate to the exterior surface of the polymeric material to yield low surface energies. Thus the coatings and articles of manufacture made with the copoly(imide oxetane)s of this invention are characterized as having an anisotropic fluorine composition. The low surface energies can be achieved with very low content of fluorinated oxetane-derived oligomer. The copolymers of this invention can enhance the viability of polyimides for many applications and may be acceptable where homopolyimide materials have been unacceptable.

A tetracarboxylic dianhydride includes: at least one acid dianhydride (A) selected from the group consisting of compounds each having an endo/exo type three-dimensional structure represented by a particular general formula and their enantiomeric compounds each having an exo/endo type three-dimensional structure; and/or an acid dianhydride (B) having an endo/endo type three-dimensional structure represented by a particular general formula, wherein a content of the acid dianhydride (B) in a total amount of the acid dianhydrides (A) and (B) is 30 to 100% by mole in a mole ratio.

Objects of the present invention are: to obtain a polyimide that is excellent in heat resistance, transparency, and optical isotropy and is soluble in an organic solvent; to provide, by using either a polyimide or a polyamic acid which is a precursor or the polyimide, a product or a member that is highly required to have heat resistance and transparency; and particularly to provide a product and a member both of which are obtained by applying a polyamic acid solution and a polyimide solution of the present invention to the surface of an inorganic substance such as glass, metal, metal oxide, or a single crystal silicon. These objects can be attained by a polyimide acid and a polyimide which are each prepared from an alicyclic tetracarboxylic dianhydride and a monomer having a fluorene structure.

A polyimide precursor composition includes a solvent mixture containing an alcohol solvent and a water-insoluble solvent that is at least one selected from the solvent group consisting of water-insoluble ketones and water-insoluble ethers; and a polyimide precursor dissolved in the solvent mixture.

A polyimide precursor solution contains resin particles and a polyimide precursor. The resin particles in the polyimide precursor solution have a volume particle size distribution with one or more peaks. The volume frequency of a peak having the highest volume frequency of the one or more peaks accounts for 90% to 100% of the total volume frequency of all peaks of the volume particle size distribution.