Cellulose acetate with a low degree of substitution

Patent metadata

Field	Value
Publication number	US-10703825-B2
Application number	US-201414775369-A
Country	US
Kind code	B2
Filing date	Mar 12, 2014
Priority date	Mar 13, 2013
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

A cellulose acetate according to the present invention has a total degree of acetyl substitution of 0.4 to 1.1 and has a compositional distribution index (CDI) of 3.0 or less, where the CDI is specified by the formula:

CDI=(Measured value of half height width of chemical composition)/(Theoretical value of half height width of chemical composition)

where the measured value of half height width of chemical composition is a half height width of chemical composition determined by analyzing a cellulose acetate propionate by HPLC, where the cellulose acetate propionate is prepared by propionylating all residual hydroxy groups of the cellulose acetate (sample); and

Theoretical value of half height width of chemical composition=2·35482√{square root over (3* DPw *( DS /3)*(1− DS /3))}/ DPw   [Math. 1]

where DS is the total degree of acetyl substitution; and DPw is a weight-average degree of polymerization determined by a GPC-light scattering method using a cellulose acetate propionate prepared by propionylating all residual hydroxy groups of the cellulose acetate (sample).

First claim

The invention claimed is:

1. A cellulose acetate having a total degree of acetyl substitution of 0.4 to 1.1 and having a compositional distribution index (CDI) as specified by a formula of greater than 1.0 to 3.0, the formula expressed as follows:
CDI=(Measured value of half height width of chemical composition)/(Theoretical value of half height width of chemical composition)

wherein:
the measured value of half height width of chemical composition is a half height width of chemical composition determined by HPLC analysis of a cellulose acetate propionate prepared by propionylating all residual hydroxy groups of the cellulose acetate (sample); and
the theoretical value of half height width of chemical composition is specified by a formula:
Theoretical value of half height width of chemical composition=2·35482√{square root over (3 *DPw* ( DS/ 3)*(1 −DS/ 3))}/ DPw   [Math. 1]

where:
DS represents the total degree of acetyl substitution; and
DPw represents a weight-average degree of polymerization determined by a GPC-light scattering method using a cellulose acetate propionate prepared by propionylating all residual hydroxy groups of the cellulose acetate (sample).

2. The cellulose acetate according to claim 1 , wherein the cellulose acetate has a CDI of greater than 1.0 to 2.8.

3. The cellulose acetate according to claim 1 , wherein the cellulose acetate has a CDI of greater than 1.0 to 2.0.

4. The cellulose acetate according to claim 1 , wherein the cellulose acetate has a standard deviation σ of 0.08 or less, where the standard deviation σ is of degrees of acetyl substitution at 2-position, 3-position, and 6-position and is specified by a formula:

σ
2

=

1

n
-
1

⁢

∑

i
=
1

n

⁢

(

x
i

-

x
_

)

2

where:
σ represents the standard deviation;
n is 3;
of x i , x 1 represents the degree of substitution at the 2-position, x 2 represents the degree of substitution at the 3-position, and x 3 represents the degree of substitution at the 6-position; and
x =(Total degree of acetyl substitution)/3.

5. The cellulose acetate according to claim 1 , wherein the cellulose acetate has a polydispersity (Mw/Mn) of 1.2 to 2.5, where the polydispersity is a value determined by a GPC-light scattering method using a cellulose acetate propionate prepared by propionylating all residual hydroxy groups of the cellulose acetate (sample).

6. The cellulose acetate according to claim 1 , wherein the cellulose acetate has a weight-average degree of polymerization (DPw) of 50 to 800, where the weight-average degree of polymerization is a value determined by a GPC-light scattering method using a cellulose acetate propionate prepared by propionylating all residual hydroxy groups of the cellulose acetate (sample).

7. A method for producing a cellulose acetate as the cellulose acetate according to claim 1 , the method comprising
partially hydrolyzing a cellulose acetate at a temperature of higher than 90° C. to give the cellulose acetate having a lower degree of substitution.

8. A formed article formed from the cellulose acetate according to claim 1 .

9. A fiber or film formed from the cellulose acetate according to claim 1 .

10. The cellulose acetate according to claim 1 , wherein the cellulose acetate has a CDI of 1.12 to 3.0.

Assignees

• Daicel Corp

Inventors

• Ukita Shizuka
• Taniguchi Hiroki
• Shimamoto Shu
• Nakamura Toshikazu

Classifications

• D01F2/28

  from organic cellulose esters or ethers, e.g. cellulose acetate · CPC title

• C08B3/28

  by precipitation · CPC title

• C08J2301/12

  Cellulose acetate · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08L1/14

  Mixed esters, e.g. cellulose acetate-butyrate · CPC title