Polymer Composition

Abstract

A polymer composition may have excellent biodegradability and absorption capacity. The polymer composition may include a polysaccharide component. The polymer composition may have excellent biodegradability and absorption capacity by controlling the ratio of amylose in the polysaccharide component, the ratio of amylopectin in the polysaccharide component, and the molecular weight of the polysaccharide component.

Claims

1. A polymer composition comprising a polysaccharide component including amylose and amylopectin, wherein: for the polysaccharide component, F is 4 or more according to Equation 1: $\begin{array}{cc}F=\mathrm{Log}\left(\mathrm{Mw}\frac{\mathrm{Ap}}{\mathrm{Ap}+\mathrm{Am}}\right)& \left[\mathrm{Equation}1\right]\end{array}$ wherein, Ap is a ratio of the amylopectin in the polysaccharide component, Am is a ratio of the amylose in the polysaccharide component, and Mw is a weight average molecular weight of the polysaccharide component.

2. The polymer composition according to claim 1, the polymer composition having a centrifuge retention capacity of 12 g/g or more according to European Disposables and Nonwovens Association (EDANA) method WSP 241.3.

3. The polymer composition according to claim 1, the polymer composition having an absorption capacity under pressure at 0.7 psi of 1.5 g/g or more according to EDANA method WSP 242.3.

4. The polymer composition according to claim 1, the polymer composition having biodegradability of 60% or more.

5. The polymer composition according to claim 1, wherein the polysaccharide component comprises one or more of starch, dextrin, or chitosan.

6. The polymer composition according to claim 1, wherein Mw is from 200,000 g/mol to 1,000,000,000 g/mol.

7. The polymer composition according to claim 1, wherein Ap is from 5% to 95%.

8. The polymer composition according to claim 1, wherein the polysaccharide component has a polysaccharide containing a functional group of Formula 1: ##STR00006## wherein M.sub.1 is hydrogen or a metal, and when M.sub.1 is the metal, the O-M.sub.1 bond is an ionic bond, and wherein the carbon-carbon double bond of Formula 1 participates in cross-linking.

9. The polymer composition according to claim 1, wherein the polysaccharide component has a polysaccharide containing a unitary body of Formula 2: ##STR00007## wherein, M.sub.1 is hydrogen or a metal, and when M.sub.1 is the metal, the O-M.sub.1 bond is an ionic bond, and wherein the carbon-carbon double bond of Formula 2 participates in cross-linking, and R.sub.1 is a hydroxy group, an amino group, or an alkylcarbonylamino group, and L.sub.1 is an alkylene group or an alkylidene group.

10. The polymer composition according to claim 1, wherein the polysaccharide component has a polysaccharide containing a functional group of Formula 3: ##STR00008## wherein, L.sub.2 is an alkylene group or an alkylidene group, M.sub.2 is hydrogen or a metal, and when M.sub.2 is the metal, the O-M.sub.2 bond is an ionic bond.

11. The polymer composition according to claim 1, wherein the polysaccharide component has a polysaccharide containing a unitary body of Formula 4: ##STR00009## wherein, R.sub.2 is a hydroxy group, an amino group, or an alkylcarbonylamino group, L.sub.2 and L.sub.3 are each independently an alkylene group or an alkylidene group, M.sub.2 is hydrogen or a metal, and when M.sub.2 is a metal, the O-M.sub.2 bond is an ionic bond.

12. The polymer composition according to claim 1, wherein the polysaccharide component is cross-linked.

13. The polymer composition according to claim 12, comprising an ester bond formed by a reaction between a hydroxy group of the polysaccharide component and a cross-linking agent.

14. The polymer composition according to claim 12, wherein the polysaccharide component is cross-linked with a cross-linking agent, and the cross-linking agent is an organic acid containing two or more carboxyl groups, or an anhydride of the organic acid.

15. The polymer composition according to claim 14, wherein the organic acid has a molecular weight from 90 g/mol to 300 g/mol, and contains from 2 to 10 carboxyl groups.

16. The polymer composition according to claim 14, wherein the cross-linking agent is citric acid, citric anhydride, pimelic acid, pimelic anhydride, adipic acid, adipic anhydride, succinic acid, or succinic anhydride.

17. The polymer composition according to claim 14, comprising from 0.5 parts by weight to 10 parts by weight of the cross-linking agent relative to 100 parts by weight of the polysaccharide component.

18. An absorbent material comprising the polymer composition of claim 1.

19. A sanitary article comprising the polymer composition of claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0124] FIGS. 1 to 5 are views showing .sup.1H NMR analysis results of polysaccharides prepared in Preparation Examples.

DETAILED DESCRIPTION

[0125] Hereinafter, the aspects of the present disclosure will be described in detail through examples and comparative examples, but the scope of the present disclosure is not limited by the following examples.

1. Evaluation of Centrifuge Retention Capacity (CRC)

[0126] Centrifuge retention capacity (CRC) was measured according to EDANA (European Disposables and Nonwovens Association) WSP 241.3. About 0.2 g (W.sub.0) of a polymer composition was placed in a non-woven bag, sealed, and then submerged in a physiological saline solution. As the physiological saline solution, an aqueous NaCl solution with a concentration of 0.9 wt % was used. The state was maintained for 30 minutes or so, water was removed from the bag for 3 minutes under a condition of 250 G using a centrifuge, and the mass (g, W.sub.2) of the bag was measured. The same operation was performed on the same non-woven bag containing no polymer composition, and the mass (g, W.sub.1) was measured.

[0127] The CRC (g/g) was calculated by substituting the measurement results into Equation A below.

[0128] The evaluation was conducted under constant temperature and humidity conditions (231 C., relative humidity: 5010%).

[00002]$\begin{array}{cc}\mathrm{CRC}\left(g/g\right)=\left\{\left[W_2\left(g\right)-W_1\left(g\right)\right]/W_0\left(g\right)\right\}-1& \left[\mathrm{Equation}A\right]\end{array}$

2. Evaluation of Absorption Capacity Under Pressure (AUP)

[0129] Absorption capacity under pressure (AUP, 0.7 psi) of a polymer composition was measured according to the standard of EDANA (European Disposables and Nonwovens Association) WSP 242.3. A 400-mesh stainless steel wire net was mounted on the bottom of a plastic cylinder with an inner diameter of 60 mm or so. Under conditions of a temperature of 232 C. and a relative humidity of 50%, about 0.90 g (W.sub.0) of the polymer composition was uniformly sprayed on the wire net, and a piston capable of further uniformly imparting a load of about 0.7 psi was installed thereon to manufacture a measuring device. As the piston, a piston with an outer diameter slightly smaller than 60 mm was used, which was installed so that it could move up and down without forming a gap with the inner wall of the cylinder. The weight (unit: g) (W.sub.3) of the measuring device was measured.

[0130] A glass filter with a diameter of 90 mm or so and a thickness of 5 mm or so was placed on the inside of a petro dish with a diameter of about 150 mm, and a physiological saline solution (NaCl aqueous solution with a concentration of 0.9 wt %) was applied to be at the same level as the upper surface of the glass filter. One sheet of filter paper with a diameter of 90 mm or so was placed thereon. The measuring device was placed on the filter paper and the physiological saline solution was absorbed for 1 hour under a load of 0.7 psi. After 1 hour, the measuring device was lifted, and the weight W.sub.4 (g) was measured.

[0131] The absorption capacity under pressure (AUP) (g/g) was calculated by substituting the respective weights as measured into Equation B below.

[00003]$\begin{array}{cc}\mathrm{AUP}\left(g/g\right)=\left[W_4\left(g\right)-W_3\left(g\right)\right]/W_0\left(g\right)& \left[\mathrm{Equation}B\right]\end{array}$

3. Measurement of Biodegradability

[0132] Biodegradability was measured in the manner specified in ISO 14855-1 (2005) standard. The above standard is a method of measuring aerobic biodegradability of plastic materials under a composting condition, which is a method that the biodegradability of a polymer composition is calculated by quantifying the amount of carbon dioxide emitted by microorganisms metabolizing the relevant material. As the polymer composition was applied to the composting condition according to the standard, the biodegradability was measured for 6 months, and the biodegradability was obtained as the ratio of the theoretical carbon dioxide generation amount and the actual carbon dioxide generation amount of the material. Here, the theoretical carbon dioxide generation amount and biodegradability are obtained according to the following equations C and D, respectively.

[00004]$\begin{array}{cc}\mathrm{Theoretical}\mathrm{carbon}\mathrm{dioxide}\mathrm{generation}\mathrm{amount}\left({\mathrm{ThCO}}_2,g/\mathrm{container}\right)=M_T{O}_T{C}_T{O}_T\left(44/12\right)& \left[\mathrm{Equation}C\right]\end{array}$

[0133] In Equation C, M.sub.TO.sub.T is the amount (g) of total dry solid content in the test material (polymer composition) added to the compost at the start of the measurement, and C.sub.TO.sub.T means the ratio (g/g) of organic carbon contained in the total dry solid content of the test material.

[00005]$\begin{array}{cc}\mathrm{Biodegradability}\left(\%\right)=\left[\left\{{\left({\mathrm{CO}}_2\right)}_T-{\left({\mathrm{CO}}_2\right)}_B\right\}/{\mathrm{ThCO}}_2\right]100& \left[\mathrm{Equation}D\right]\end{array}$

[0134] In Equation D, (CO.sub.2).sub.T is the accumulated amount (g/container) of carbon dioxide generated from the composting container containing the test material, (CO.sub.2).sub.B is the average (g/container) of carbon dioxide accumulated amounts generated from the inoculum source container, and ThCO.sub.2 is the theoretical carbon dioxide generation amount confirmed in Equation C above.

4. Molecular Weight Measurement of Polysaccharide Component

[0135] A molecular weight of a polysaccharide component was evaluated in the following manner.

(1) Preparation of Mobile Phase

[0136] A mobile phase A was prepared by filtering 1000 mL of a 150 mM NaNO.sub.3 aqueous solution containing 0.02 wt % of NaN.sub.3 using a solvent clarification system (Millipore Millisolve Kit, MilliporeSigma).

(2) Preparation of Sample Solution

[0137] A sample intended to be measured was collected in an amount of 25 mg, and mixed with 5 mL of a 150 mM NaNO.sub.3 aqueous solution containing 0.02 wt % of NaN.sub.3, and then a sample solution was prepared by heating the mixture at 80 C. for 20 hours, and then filtering it with a 0.4 m Nylon Syringe Filter.

(3) GPC (Gel Permeation Chromatography)/MALS (Multi-Angle Light Scattering Detection) Conditions

[0138] The molecular weight was evaluated using the sample solution and the mobile phase A in the following manner. [0139] Measuring instrument: Agilent GPC (Agilent 1200 series, U.S.) [0140] Stationary phase: connecting Shodex OH-Pak 804 column and Shodex OH-Pak 80 column [0141] Mobile phase: A; 0.02% NaN.sub.3, 150 mM NaNO.sub.3 aqueous solution=100 (v/v %) [0142] Flow rate: 0.4 mL/min [0143] Stationary phase temperature: 25 C. [0144] Injected amount: 100 l (0.45 m filtered) [0145] Analysis time: 120 minutes

5. Content Measurement of Amylopectin and Amylose in Polysaccharide Component

[0146] Contents of amylopectin and amylose in a polysaccharide component were evaluated according to the method described in a paper (Potato Research 31 (1988) 241-246).

[0147] First, a sample was prepared by dissolving about 5 mg of a polysaccharide (starch) in about 1 mL of sterile water (Step 1), and heated to 95 C. for about 15 minutes in a constant temperature water bath (Step 2).

[0148] Subsequently, about 20 l of the sample was placed in a cuvette (Step 3), and about 980 l of an iodine solution was added thereto and mixed (Step 4).

[0149] Subsequently, absorbance of the sample mixed with the iodine solution at wavelengths of 525 nm and 700 nm was measured and recorded, respectively (Step 5). The absorbance was measured using KLAB's OPTIZEN POP model.

[0150] About 20 l of water was placed in another cuvette, 980 l of the iodine solution was added thereto, and mixed (Step 6). For the solution of Step 6, absorbance at wavelengths of 525 nm and 700 nm was measured and recorded, respectively, in the same manner as in Step 5 (Step 7).

[0151] The absorbance obtained in Step 7 was subtracted from the absorbance obtained in Step 5, and the ratio (%) of amylose was confirmed according to Equation E below (Step 8).

[00006]$\begin{array}{cc}\mathrm{PA}=3.039-\frac{7.154\frac{{\mathrm{OD}}_{700}}{{\mathrm{OD}}_{525}}}{3.048\frac{{\mathrm{OD}}_{700}}{{\mathrm{OD}}_{525}}}-19.192& \left[\mathrm{Equation}E\right]\end{array}$

[0152] In Equation E, PA is the ratio (%) of amylose, OD.sub.700 is the value obtained by subtracting the absorbance at a wavelength of 700 nm measured in Step 7 from the absorbance at a wavelength of 700 nm measured in Step 5, and OD.sub.525 is the value obtained by subtracting the absorbance at a wavelength of 525 nm measured in Step 7 from the absorbance at a wavelength of 525 nm measured in Step 5.

Preparation Example 1

[0153] Starch (Compound A) containing a modified monosaccharide unitary body of Formula A below was prepared in the following manner. The modified monosaccharide unitary body of Formula A below is a monosaccharide unitary body into which a functional group derived from sodium acetate has been introduced.

##STR00005##

[0154] As the starch material, starch with a weight average molecular weight (Mw) of about 180,000,000 g/mol or so, an amylopectin ratio of about 81%, and an amylose ratio of about 19% was used. The ratio of amylose is the value confirmed by Equation E above, and the ratio of amylopectin is the value obtained by subtracting the ratio of amylose from 100%.

[0155] The starch, isopropyl alcohol (IPA), and NaOH aqueous solution (concentration: about 40%) were mixed in a 500 mL RBF (Round Bottom Flask), and stirred at room temperature for about 20 minutes or so. The weight ratio of the mixing was set to 1:4:0.8 (starch:IPA:NaOH aqueous solution). Subsequently, about 80 parts by weight of sodium monochloroacetate was added thereto relative to 100 parts by weight of the starch, the temperature was raised to 60 C., and then stirred for 1 hour or so, and the temperature was cooled to room temperature. After cooling to room temperature, the solvent was removed from water, the reactant was dissolved in water, precipitated in methanol to remove water-soluble impurities, filtered to recover starch, and dried in a vacuum drying oven at 40 C. for about 12 hours to obtain a solid target product (Compound A).

[0156] The substitutional rate of the obtained target product (Compound A) can be obtained through a .sup.1H NMR analysis. The .sup.1H NMR analysis is performed at room temperature using a .sup.1H NMR spectrometer including a Varian Unity Inova (500 MHz) spectrometer with a triple resonance 5 mm probe. In the .sup.1H NMR analysis, Bruker's Avance Neo instrument was used.

[0157] Specifically, 50 mg of the obtained solid target product (Compound A) and 200 mg of 30% D2DSO4 in D2O solution are mixed, stirred at 50 C. for 1 hour or so to induce a hydrolysis reaction, and then the .sup.1H NMR analysis can be performed.

[0158] The .sup.1H NMR analysis results of the target product (Compound A) are shown in FIG. 1. The substitutional rate confirmed by the above analysis was about 60% or so.

Preparation Example 2

[0159] Modified starch was prepared in the same manner as in Preparation Example 1, except that as the starch, starch with a weight average molecular weight (Mw) of about 12,000,000 g/mol or so, an amylopectin ratio of about 75%, and an amylose ratio of about 25% was used.

[0160] The .sup.1H NMR results of the starch identified in the same manner as Preparation Example 1 are the same as in FIG. 2 below, and the substitutional rate confirmed from the results was about 60% or so.

Preparation Example 3

[0161] Modified starch was prepared in the same manner as in Preparation Example 1, except that as the starch, starch with a weight average molecular weight (Mw) of about 2,000,000 g/mol or so, an amylopectin ratio of about 69%, and an amylose ratio of about 31% was used.

[0162] The .sup.1H NMR results of the starch identified in the same manner as in Preparation Example 1 are the same as in FIG. 3, and the substitutional rate confirmed from the results was about 70% or so.

Preparation Example 4

[0163] Modified starch was prepared in the same manner as in Preparation Example 1, except that as the starch, starch with a weight average molecular weight (Mw) of about 920,000 g/mol or so, an amylopectin ratio of about 58%, and an amylose ratio of about 42% was used.

[0164] The .sup.1H NMR results of the starch identified in the same manner as in Preparation Example 1 are the same as in FIG. 4, and the substitutional rate confirmed from the results was about 52% or so.

Preparation Example 5

[0165] Modified starch was prepared in the same manner as in Preparation Example 1, except that as the starch, starch with a weight average molecular weight (Mw) of about 450,000 g/mol or so, an amylopectin ratio of about 19%, and an amylose ratio of about 81% was used.

[0166] The .sup.1H NMR results of the starch identified in the same manner as in Preparation Example 1 are the same as in FIG. 5, and the substitutional rate confirmed from the results was about 50% or so.

Preparation Example 6

[0167] Modified starch was prepared in the same manner as in Preparation Example 1, except that as the starch, starch with a weight average molecular weight (Mw) of about 140,000 g/mol or so, an amylopectin ratio of about 6%, and an amylose ratio of about 94% was used.

[0168] As a result of .sup.1H NMR of the starch identified in the same manner as in Preparation Example 1, the substitutional rate was about 60% or so.

Example 1

[0169] The starch prepared in Preparation Example 1 was dissolved in distilled water, and a cross-linking agent (citric acid) was added at a ratio of about 3 parts by weight relative to 100 parts by weight of the starch. It was stirred at room temperature for 30 minutes or so, transferred to a steel tray, and dried in an oven at about 40 C. or so for 12 hours or so. Subsequently, in a state where the temperature was raised to about 80 C. or so, it was cross-linked for 2 hours or so to prepare a desired polymer composition.

Example 2

[0170] A polymer composition was prepared in the same manner as in Example 1, except that the starch prepared in Preparation Example 2 was used.

Example 3

[0171] A polymer composition was prepared in the same manner as in Example 1, except that the starch prepared in Preparation Example 3 was used.

Example 4

[0172] A polymer composition was prepared in the same manner as in Example 1, except that the starch prepared in Preparation Example 4 was used.

Example 5

[0173] A polymer composition was prepared in the same manner as in Example 1, except that the starch prepared in Preparation Example 5 was used.

Comparative Example 1

[0174] A polymer composition was prepared in the same manner as in Example 1, except that the starch prepared in Preparation Example 6 was used.

[0175] The Mw, Am, and Ap values, and F values of the polymer compositions of Examples and Comparative Example in Equation 1, as well as the CRC, AUP, and biodegradability measured for each polymer composition were summarized and described in Table 1 below. In Table 1 below, the unit of Mw is 1,000 g/mol.

TABLE-US-00001 TABLE 1 Example Comparative Example 1 2 3 4 5 1 F 8.2 7.0 6.1 5.7 4.9 3.9 Mw 180,000 12,000 2,000 920 450 140 Ap (%) 81 75 69 58 19 6 Am (%) 19 25 31 42 81 94 CRC (g/g) 45.3 44.3 39.5 34.3 30.5 11.7 AUP (g/g) 5.51 4.73 3.59 4.52 4.21 1.62 Biodegradability (%) 75.7 85.8 94.2 99.3 99.5 99.5

[0176] From the results of Table 1, it can be confirmed that the polymer compositions in which F in Equation 1 is 4 or more simultaneously exhibit excellent absorption properties and biodegradability, whereas in the case of Comparative Example 1 in which the F is 3.9, biodegradability has been secured, but absorption properties are significantly reduced.