Provided is a biodegradable resin molded product that exhibits excellent processability and sufficient strength as the molded product, is advantageous in terms of cost and at the same time, has excellent biodegradability under an environment, in particular, marine biodegradability, and a method for producing the same, and pellets used therefor. The molded product is produced using a biodegradable resin composition including a biodegradable resin and heavy calcium carbonate particles in a range by mass of 50:50 to 10:90.

Provided is a biodegradable resin molded product that exhibits excellent processability and sufficient strength as the molded product, is advantageous in terms of cost and at the same time, has excellent biodegradability under an environment, in particular, marine biodegradability, and a method for producing the same, and pellets used therefor. The molded product is produced using a biodegradable resin composition including a biodegradable resin and heavy calcium carbonate particles in a range by mass of 50:50 to 10:90.

A method of producing a polyoxalate copolymer using, as a diol component, an ethylene glycol and other diol in combination, and subjecting the diol component and a dimethyl oxalate to an esterification polymerization reaction. The esterification polymerization reaction is executed through a step that includes: a step of a normal-pressure polymerization inclusive of the esterification polymerization reaction of a oxalic acid formed from the dimethyl oxalate and the ethylene glycol, and a step of a reduced-pressure polymerization that is accompanied by a removal of diol after the step of the normal-pressure polymerization. Further, the other diol is added to the polymerization system at a predetermined temperature in the step of the normal-pressure polymerization.

A thiol-yne polymeric material and methods for producing said polymers are disclosed. The material is produced by the radically mediated polymerization of monomers having alkyne and thiol functional groups. The alkyne moiety, internal or terminal, may react with one or two thiols. Degradable monomers may be used to form degradable polymers.

A polylactic acid composition including polylactic acid and an ethylene resin, characterized in that the ethylene resin is selected so that a melt flow rate ratio (RMF), defined by the following equation (1): RMF=A.sub.PLA/B.sub.PE (1) where A.sub.PLA represents the melt flow rate of the polylactic acid measured at 210° C. and 2.16 kg, and B.sub.PE represents the melt flow rate of the ethylene resin measured at 190° C. and 2.16 kg, in a range of 0.5 to 10 is satisfied. Also disclosed is a stretch-molded bottle formed using the polylactic acid composition. The polylactic acid composition is preferably used in molding a container particularly improved in alkali resistance and environmental stress crack resistance.

A composition comprising a continuous thermoplastic polymer matrix having a melting point greater than 110° C. and, distributed within the matrix, particles of hydrophilic natural fiber material having a sieved size of less than 1.0 mm, the weight ratio of the thermoplastic polymer to the wood particles being from 99:1 to 35:65. An improvement in biodegradability of biopolymers, such as PLA, can be achieved. On the other hand, the addition of wood fibers enhances the material's ability to resist thermal deformation. The present compositions can be used for manufacturing hollow structures, by injection blow molding, of bottles with a wall thickness between 0.1 mm and 5 mm, in particular from 0.3 to 1 mm or continuous extruded products with a wall thickness from 0.3 mm to 1.5 mm.

A composition comprising a continuous thermoplastic polymer matrix having a melting point greater than 110° C. and, distributed within the matrix, particles of hydrophilic natural fiber material having a sieved size of less than 1.0 mm, the weight ratio of the thermoplastic polymer to the wood particles being from 99:1 to 35:65. An improvement in biodegradability of biopolymers, such as PLA, can be achieved. On the other hand, the addition of wood fibers enhances the material's ability to resist thermal deformation. The present compositions can be used for manufacturing hollow structures, by injection blow molding, of bottles with a wall thickness between 0.1 mm and 5 mm, in particular from 0.3 to 1 mm or continuous extruded products with a wall thickness from 0.3 mm to 1.5 mm.

Resin particles include mother particles containing a biodegradable resin, in which an alkali metal atomic weight A present on a resin particle surface with respect to a total atomic weight present on the resin particle surface, which is measured by an X-ray photoelectron spectroscopy, and an alkali metal atomic weight B present in the resin particles with respect to the total atomic weight present on the resin particles, which is measured by a fluorescent X-ray spectroscopy, satisfy a relationship of 0≤(A/B)<0.15 and 0.005 atomic %≤B≤0.5 atomic %.

A method for producing an injection-molded article of a polylactic acid resin composition, including filling a melt-kneaded product of a polylactic acid resin composition containing a polylactic acid resin, a plasticizer containing a polyoxyalkylene group or an oxyalkylene group, and a mold releasing agent having a melting point of from 20° to 75° C. in an injection-molding machine to mold in a die, wherein the method is characterized in that the above-mentioned injection-molding machine comprises a cylinder at least a part of which has a set temperature of 200° C. or higher, that the die has a surface temperature of 85° C. or higher, and that the die has a surface roughness of 1.0 μm or less.

A method for producing a poly(3-hydroxybutyrate) resin-containing composition for melt processing includes: heating a material containing a poly(3-hydroxybutyrate) resin to a temperature equal to or higher than a melting point peak temperature in differential scanning calorimetry analysis of the poly(3-hydroxybutyrate) resin and equal to or lower than a melting point peak end temperature in the differential scanning calorimetry analysis of the poly(3-hydroxybutyrate) resin, wherein the difference between the melting point peak temperature and the melting point peak end temperature of the poly(3-hydroxybutyrate) resin is 10° C. or more; and extruding the heated material to obtain a composition for melt processing that has a new crystallization peak at a temperature higher than the melting point peak temperature.