A cellulose resin wherein a hydrogen atom of a hydroxy group of cellulose is substituted with a long-chain component which is a linear saturated aliphatic acyl group having 14 or more carbon atoms and a short-chain component which is an acyl group (propionyl group) having 3 carbon atoms, the degree of substitution with the long-chain component (DS.sub.Lo) and the degree of substitution with the short-chain component (DS.sub.Sh) satisfy the following conditional expressions (1) and (2):
DS.sub.Lo+DS.sub.Sh≥2.1  (1)
4≤DS.sub.Sh/DS.sub.Lo≤12  (2),
the Izod impact strength is 5.0 kJ/m.sup.2 or more, and the MFR (melt flow rate at 200° C. and under a load of 5 kg) is 10 g/10 min or more.

A cellulose resin wherein a hydrogen atom of a hydroxy group of cellulose is substituted with a long-chain component which is a linear saturated aliphatic acyl group having 14 or more carbon atoms and a short-chain component which is an acyl group (propionyl group) having 3 carbon atoms, the degree of substitution with the long-chain component (DS.sub.Lo) and the degree of substitution with the short-chain component (DS.sub.Sh) satisfy the following conditional expressions (1) and (2):
DS.sub.Lo+DS.sub.Sh≥2.1  (1)
4≤DS.sub.Sh/DS.sub.Lo≤12  (2),
the Izod impact strength is 5.0 kJ/m.sup.2 or more, and the MFR (melt flow rate at 200° C. and under a load of 5 kg) is 10 g/10 min or more.

A cellulose resin wherein a hydrogen atom of a hydroxy group of cellulose is substituted with a long-chain component which is a linear saturated aliphatic acyl group having 14 or more carbon atoms and a short-chain component which is an acyl group (propionyl group) having 3 carbon atoms, the degree of substitution with the long-chain component (DS.sub.Lo) and the degree of substitution with the short-chain component (DS.sub.Sh) satisfy the following conditional expressions (1) and (2):

DS.sub.Lo+DS.sub.Sh2.1(1)

4DS.sub.Sh/DS.sub.Lo12(2),

the Izod impact strength is 5.0 kJ/m.sup.2 or more, and the MFR (melt flow rate at 200 C. and under a load of 5 kg) is 10 g/10 min or more.

A cellulose resin wherein a hydrogen atom of a hydroxy group of cellulose is substituted with a long-chain component which is a linear saturated aliphatic acyl group having 14 or more carbon atoms and a short-chain component which is an acyl group (propionyl group) having 3 carbon atoms, the degree of substitution with the long-chain component (DS.sub.Lo) and the degree of substitution with the short-chain component (DS.sub.Sh) satisfy the following conditional expressions (1) and (2):

DS.sub.Lo+DS.sub.Sh2.1(1)

4DS.sub.Sh/DS.sub.Lo12(2),

the Izod impact strength is 5.0 kJ/m.sup.2 or more, and the MFR (melt flow rate at 200 C. and under a load of 5 kg) is 10 g/10 min or more.

Provided is a method for producing hydroxypropyl methylcellulose acetate succinate by which particle density increment is suppressed and dissolution time is shortened. The method for producing hydroxypropyl methylcellulose acetate succinate essentially includes a liquid removal step, a first drying step, and a second drying step, wherein the first drying step involves drying of hydroxypropyl methylcellulose acetate succinate using a fluid-bed dryer until it reaches a water content of 30% by mass while maintaining the product temperature at 28 C. or lower.

Provided is a method for producing hydroxypropyl methylcellulose acetate succinate by which particle density increment is suppressed and dissolution time is shortened. The method for producing hydroxypropyl methylcellulose acetate succinate essentially includes a liquid removal step, a first drying step, and a second drying step, wherein the first drying step involves drying of hydroxypropyl methylcellulose acetate succinate using a fluid-bed dryer until it reaches a water content of 30% by mass while maintaining the product temperature at 28 C. or lower.

Provided is an industrial and efficient method for producing hydroxypropyl methylcellulose acetate succinate that exhibits an enhanced dissolution rate into a solvent. This method includes a liquid removal step, a first drying step, and a second drying step, wherein the first drying step involves drying hydroxypropyl methylcellulose acetate succinate under reduced pressure until it reaches a water content above 0% by mass and lower than or equal to 30% by mass while maintaining the product temperature above 0 C. and lower than or equal to 25 C.

Provided is an industrial and efficient method for producing hydroxypropyl methylcellulose acetate succinate that exhibits an enhanced dissolution rate into a solvent. This method includes a liquid removal step, a first drying step, and a second drying step, wherein the first drying step involves drying hydroxypropyl methylcellulose acetate succinate under reduced pressure until it reaches a water content above 0% by mass and lower than or equal to 30% by mass while maintaining the product temperature above 0 C. and lower than or equal to 25 C.