Polymer composition containing graft polymer of cellulose acetate and lactone, and method for producing same

Abstract

The present invention provides a novel graft polymer composition which contains a graft polymer of cellulose acetate and a lactone and which achieves both excellent thermoplasticity and suppression of bleed out.　Provided is a polymer composition which contains a graft polymer of cellulose acetate and a lactone, wherein the proportion of a methanol-soluble material of the polymer composition as measured via the method below is in the range of 13-33 mass%. (Method for measuring proportion of methanol-soluble material) Under atmospheric pressure, in a 20°C environment, acetone is dissolved in 144 ml with respect to 24 g of the polymer composition, 1.5 L of methanol is added, and stirring is carried out for 12 hours. A mixture thus obtained is filtered with a PTFE membrane filter having a pore diameter of 1 μm, and a filter residue is collected. The obtained filter residue is put into 0.5 L of methanol again, and stirring is carried out for 1 hour. A mixture thus obtained is filtered with a PTFE membrane filter having a pore diameter of 1 μm, and a filter residue and a filtrate are collected. The obtained filter residue is put into 0.5 L of methanol again, and stirring is carried out for 1 hour. A mixture thus obtained is filtered with a PTFE membrane filter having a pore diameter of 1 μm, and a filter residue and a filtrate are collected. After the pH of the filtrate is confirmed to be 7, the filter residue is added to 1 L of methanol, and stirring is carried out for 12 hours. A mixture thus obtained is filtered with a PTFE membrane filter having a pore diameter of 1μm, and a filter residue is collected. The obtained filter residue is dried at 40°C for 12 hours in a vacuum, and a dry mass is thus obtained. From the dry mass of the polymer composition before purification and the dry mass of the polymer composition after the purification, the proportion of the methanol-soluble material contained in the polymer composition is calculated. Methanol-soluble component of polymer composition = dry mass of polymer composition before purification - dry mass of polymer composition after purification Proportion of methanol-soluble material contained in polymer composition = (mass of methanol-soluble component of polymer composition) / dry mass of polymer composition after purification × 100 (mass%)

Description

Polymer composition containing graft polymer of cellulose acetate and lactones, and method for producing the same

[0001] The present disclosure relates to a polymer composition containing a graft polymer of cellulose acetate and a lactone, and a method for producing the same.

[0002] In recent years, there has been a growing demand to replace petroleum-derived plastics, which are contributing to environmental problems such as global warming and marine pollution, with biomass-derived plastics.

[0003] Cellulose materials have been attracting attention as biomass-derived materials. For example, cellulose acetate is one of the cellulose derivatives with the lowest price and the largest industrial production volume.

[0004] Yoshioka, M. ; Hagiwara, N. ; Shiraishi, N. Thermoplasticization of cellulose acetates by grafting of cyclic esters. Cellulose1999, 6(3), 193-212.

[0005] For example, Non-Patent Document 1 discloses a plastic in which the thermoplasticity is improved without impairing the biodegradability of cellulose diacetate (CDA) by graft polymerizing polycaprolactone (PCL) onto CDA using tin 2-ethylhexanoate (SnEht2) as a catalyst.

[0006] However, the inventors of the present disclosure have conducted studies and found that when an attempt is made to increase the thermoplasticity of the graft polymer by graft polymerizing polycaprolactone (PCL) onto cellulose acetate, a problem occurs in that by-products such as caprolactone homopolymers gradually bleed out from the resulting graft polymer composition.

[0007] A primary object of the present disclosure is to provide a novel graft polymer composition comprising a graft polymer of cellulose acetate and a lactone, which has both excellent thermoplasticity and suppressed bleed-out. Another object of the present disclosure is to provide a novel method for producing the polymer composition.

[0008] The inventors of the present disclosure have conducted extensive research and have found that a novel graft polymer composition containing a graft polymer of cellulose acetate and lactones can be obtained by setting the ratio of methanol-soluble matter within a predetermined range. The inventors have also found that such a graft polymer composition can be suitably produced by adjusting the mass ratio of the cellulose acetate to the lactones within a predetermined range in the polymerization step in which the cellulose acetate and the lactones are graft polymerized to obtain a polymer composition. The present disclosure is an invention that was completed based on these findings and through further research.

[0009] That is, the present disclosure provides the following aspects of the invention. Item 1. A polymer composition comprising a graft polymer of cellulose acetate and lactones, wherein the polymer composition has a methanol-soluble matter content measured by the following method in the range of 13% by mass or more and 33% by mass or less. (Method for measuring the methanol-soluble matter content) Under atmospheric pressure and at 20°C, 24 g of the polymer composition is dissolved in 144 ml of acetone, 1.5 L of methanol is added, and the mixture is stirred for 12 hours. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate is recovered. The resulting filtrate is again added to 0.5 L of methanol and stirred for 1 hour. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and the filtrate are recovered. The resulting filtrate is again added to 0.5 L of methanol and stirred for 1 hour. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and the filtrate are recovered. After confirming that the pH of the filtrate is 7, the filtrate is added to 1 L of methanol and stirred for 12 hours. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate is recovered. The resulting filtrate is vacuum dried at 40°C for 12 hours to obtain a dry mass. The proportion of methanol-soluble matter contained in the polymer composition is calculated from the dry masses of the polymer composition before purification and the polymer composition after purification. Methanol-soluble component of polymer composition = dry mass of polymer composition before purification - dry mass of polymer composition after purification. Proportion of methanol-soluble matter contained in polymer composition = (mass of methanol-soluble component of polymer composition) / dry mass of polymer composition after purification × 100 (mass%). Item 2. The polymer composition according to Item 1, wherein the methanol-soluble component comprises a homopolymer of a lactone. Item 3. Item 2. The polymer composition according to item 2, wherein the methanol-soluble matter contains a homopolymer of the lactones in an amount of 60 mass% or more. Item 4. The polymer composition according to any one of items 1 to 3, wherein the lactones include ε-caprolactone. Item 5. The polymer composition according to any one of items 1 to 4, wherein the cellulose acetate has a degree of acetyl substitution (DS) of 1.0 to 2.9.Item 6. The polymer composition according to any one of Items 1 to 5, wherein the molar substitution (MS) of the lactones per glucose unit of the cellulose acetate is 0.1 to 5. Item 7. The polymer composition according to any one of Items 1 to 6, wherein the methanol-soluble matter in the polymer composition is a phosphorus compound. Item 8. The polymer composition according to any one of Items 1 to 6, wherein the polymer composition is substantially free of metals selected from Group 4 and Group 14. Item 9. A method for producing a polymer composition, comprising a polymerization step of graft polymerizing cellulose acetate and lactones to obtain a polymer composition, wherein the mass ratio of the cellulose acetate to the lactones mixed in the polymerization step is in the range of 0.25 to 2.4 parts by mass per part by mass of the cellulose acetate. Item 10. The method for producing a polymer composition according to Item 9, wherein the polymer composition comprises a homopolymer of the lactones. Item 11. The method for producing a polymer composition according to Item 9 or 10, wherein the lactones include ε-caprolactone. Item 12. The method for producing a polymer composition according to any one of Items 9 to 11, wherein the cellulose acetate has a degree of acetyl substitution (DS) of 1.0 to 2.9. Item 13. The method for producing a polymer composition according to any one of Items 9 to 12, wherein the cellulose acetate has a degree of molar substitution (MS) of the lactones per glucose unit of 0.1 to 5.

[0010] According to the present disclosure, there is provided a novel graft polymer composition comprising a graft polymer of cellulose acetate and a lactone, which has both excellent thermoplasticity and suppressed bleed-out. Furthermore, according to the present disclosure, there is provided a novel method for producing the polymer composition. Furthermore, the production method of the present disclosure is preferred from the viewpoints of the environment and cost, since it does not require a purification step after polymerization.

[0011] 1 is a graph showing the particle size distribution of cellulose diacetate pulverized in the examples.

[0012] The polymer composition of the present disclosure is a polymer composition containing a graft polymer of cellulose acetate and lactones. The polymer composition is characterized in that the proportion of methanol-soluble matter measured by the following method is in the range of 13 mass% or more and 33 mass% or less. By having such a configuration, the polymer composition of the present disclosure achieves both excellent thermoplasticity and suppression of bleed-out.

[0013] (Method for measuring the proportion of methanol-soluble matter) Under atmospheric pressure and in a 20°C environment, 24 g of the polymer composition was dissolved in 144 ml of acetone, 1.5 L of methanol was added, and the mixture was stirred for 12 hours. The resulting mixture was filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate was collected. The resulting filtrate was again added to 0.5 L of methanol and stirred for 1 hour. The resulting mixture was filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and filtrate were collected. The resulting filtrate was again added to 0.5 L of methanol and stirred for 1 hour. The resulting mixture was filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and filtrate were collected. After confirming that the pH of the filtrate was 7, the filtrate was added to 1 L of methanol and stirred for 12 hours. The resulting mixture was filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate was collected. The resulting filtered product is vacuum dried at 40°C for 12 hours to obtain a dry mass. The proportion of methanol-soluble matter contained in the polymer composition is calculated from the dry masses of the polymer composition before and after purification. Methanol-soluble component of polymer composition = dry mass of polymer composition before purification - dry mass of polymer composition after purification. Proportion of methanol-soluble matter contained in polymer composition = (mass of methanol-soluble component of polymer composition) / dry mass of polymer composition after purification × 100 (mass%)

[0014] The method for producing a polymer composition according to the present disclosure includes a polymerization step of graft-polymerizing cellulose acetate and lactones to obtain a polymer composition, and is characterized in that the mass ratio of the cellulose acetate to the lactones mixed in the polymerization step is in the range of 0.25 to 2.4 parts by mass per part by mass of cellulose acetate. By virtue of having such a configuration, the method for producing a polymer composition according to the present disclosure can suitably produce the polymer composition according to the present disclosure.

[0015] Preferred embodiments of the present disclosure will be described in detail below. Each configuration and combination thereof in each embodiment is merely an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate without departing from the spirit of the present disclosure. The present disclosure is not limited by the embodiments, but only by the scope of the claims. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0016] In this disclosure, the range "X to Y" means "X or more and Y or less." Unless otherwise noted, all tests were conducted at room temperature (20°C ± 5°C).

[0017] [Polymer Composition] The polymer composition of the present disclosure contains a graft polymer of cellulose acetate and lactones, and has a methanol-soluble matter content in the range of 13 mass% to 33 mass%. That is, the polymer composition of the present disclosure contains the graft polymer of cellulose acetate and lactones and the methanol-soluble matter dissolved by the above-mentioned (method for measuring the methanol-soluble matter content).

[0018] The polymer composition of the present disclosure may have a proportion of methanol soluble matter measured by the above-mentioned method in the range of 13% by mass or more and 33% by mass or less. From the viewpoint of more suitably exhibiting the effects of the present disclosure, the proportion is preferably 15% by mass or more, more preferably 18% by mass or more, and even more preferably 20% by mass or more, and is preferably 32.9% by mass or less, more preferably 32.8% by mass or less, and even more preferably 32.7% by mass or less. Preferred ranges include about 13 to 32.9% by mass, about 13 to 32.8% by mass, about 13 to 32.7% by mass, about 15 to 32.9% by mass, about 15 to 32.8% by mass, about 15 to 32.7% by mass, about 18 to 32.9% by mass, about 18 to 32.8% by mass, about 18 to 32.7% by mass, about 20 to 32.9% by mass, about 20 to 32.8% by mass, and 20 to 32.7% by mass.

[0019] In order to adjust the proportion of methanol soluble matter measured by the above-mentioned method in the polymer composition of the present disclosure to a specific range of 13 mass % or more and 33 mass % or less, for example, it is effective to highly pulverize dried cellulose acetate using a plurality of mills in the production process of the polymer composition of the present disclosure described below, and to reduce the proportion of lactones used relative to cellulose acetate (specifically, the lactones are used in a range of 0.25 to 2.4 parts by mass, 0.25 to 2.0 parts by mass, 0.25 to 1.5 parts by mass, 0.30 to 2.4 parts by mass, 0.30 to 2.0 parts by mass, 0.30 to 1.5 parts by mass, 0.35 to 2.4 parts by mass, 0.35 to 2.0 parts by mass, 0.35 to 1.5 parts by mass, etc., per part by mass of cellulose acetate). In the past, in the graft polymerization of cellulose acetate and lactones, a method of highly pulverizing dried cellulose acetate to reduce the proportion of lactones used has not been adopted. To ensure sufficient progress of the graft polymerization of cellulose acetate and lactones, the proportion of lactones used generally exceeds 2.4 parts by mass. Therefore, even when graft polymerization of cellulose acetate and lactones is carried out in the prior art, the proportion of methanol-soluble matter measured by the above-mentioned method does not reach 33% by mass or less, and a larger amount of methanol-soluble matter is contained. Furthermore, when the obtained graft polymer composition is purified, most of the methanol-soluble matter is removed, resulting in a proportion significantly below 13% by mass. Therefore, in the prior art, the polymer composition of the present disclosure in which the proportion of methanol-soluble matter is set within the specific range of 13% by mass or more and 33% by mass or less has not been produced. Furthermore, it has not been known that the polymer composition exhibits both excellent thermoplasticity and suppressed bleed-out.

[0020] The methanol-soluble matter is a component contained in the polymer composition during the graft polymerization of cellulose acetate and lactones. That is, as described below, the methanol-soluble matter may include at least one of raw materials (cellulose acetate, lactones, catalysts, etc.) and by-products (homopolymers of lactones, etc.) used in the graft polymerization of cellulose acetate and lactones. The polymer composition of the present disclosure typically contains a homopolymer of lactones as the methanol-soluble matter.

[0021] From the viewpoint of suitably exerting the effects of the present invention, the degree of acetyl substitution (DS) of the cellulose acetate (the degree of acetyl substitution (DS) of the starting cellulose acetate used in the polymerization of the polymer composition of the present disclosure) is preferably 1.0 or more, more preferably 1.4 or more, even more preferably 1.8 or more, and still more preferably 1.9 or more, and is preferably 2.9 or less, more preferably 2.8 or less, even more preferably 2.7 or less, and still more preferably 2.6 or less. Preferred ranges include 1.0 to 2.9, 1.0 to 2.8, 1.0 to 2.7, 1.0 to 2.6, 1.4 to 2.9, 1.4 to 2.8, 1.4 to 2.7, 1.4 to 2.6, 1.8 to 2.9, 1.8 to 2.8, 1.8 to 2.7, 1.8 to 2.6, 1.9 to 2.9, 1.9 to 2.8, 1.9 to 2.7, and 1.9 to 2.6. The degree of acetyl substitution (DS) is a value measured by NMR. The cellulose acetate is preferably cellulose diacetate (for example, the degree of acetyl substitution (DS) is 1.8 to 2.6).

[0022] Furthermore, from the viewpoint of suitably exerting the effects of the present invention, in the polymer composition of the present disclosure, the molar substitution (MS) of lactones per glucose unit of cellulose acetate is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and still more preferably 0.4 or more, and is preferably 5.0 or less, more preferably 4.5 or less, and still more preferably 3.5 or less, and preferred ranges include 0.1 to 5.0, 0.1 to 4.5, 0.1 to 3.5, 0.1 to 3.4, 0.2 to 5.0, 0.2 to 4.5, 0.2 to 3.5, 0.2 to 3.4, 0.3 to 5.0, 0.3 to 4.5, 0.3 to 3.5, 0.3 to 3.4, 0.4 to 5.0, 0.4 to 4.5, 0.4 to 3.5, and 0.4 to 3.4. The molar substitution (MS) is a value measured by NMR. Higher molar substitution (MS) values ​​tend to increase the flexibility of the polymer composition, allowing for better control of the hardness of the material.

[0023] From the viewpoint of suitably exerting the effects of the invention of the present disclosure, the weight average molecular weight (Mw) of the graft polymer contained in the polymer composition of the present disclosure is preferably 20,000 or more, more preferably 30,000 or more, and even more preferably 40,000 or more, and is preferably 1,000,000 or less, more preferably 900,000 or less, and even more preferably 800,000 or less. Preferred ranges include 20,000 to 1,000,000, 20,000 to 900,000, 20,000 to 800,000, 30,000 to 1,000,000, 30,000 to 900,000, 30,000 to 800,000, 40,000 to 1,000,000, 40,000 to 900,000, and 40,000 to 800,000.

[0024] Furthermore, from the viewpoint of suitably exerting the effects of the invention of the present disclosure, the number average molecular weight (Mn) of the graft polymer contained in the polymer composition of the present disclosure is preferably 10,000 or more, more preferably 20,000 or more, and even more preferably 30,000 or more, and is preferably 700,000 or less, more preferably 600,000 or less, and even more preferably 500,000 or less. Preferred ranges include 10,000 to 700,000, 10,000 to 600,000, 10,000 to 500,000, 20,000 to 700,000, 20,000 to 600,000, 20,000 to 500,000, 30,000 to 700,000, 30,000 to 600,000, and 30,000 to 500,000.

[0025] Furthermore, from the viewpoint of suitably exerting the effects of the invention of the present disclosure, the molecular weight distribution (Mn / Mw) of the graft polymer contained in the polymer composition of the present disclosure is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less, and examples thereof include 1.2 or more, 1.3 or more, and 1.4 or more. Preferred ranges include 1.2 to 3.0, 1.2 to 2.5, 1.2 to 2.0, 1.3 to 3.0, 1.3 to 2.5, 1.3 to 2.0, 1.4 to 3.0, 1.4 to 2.5, and 1.4 to 2.0.

[0026] In the present disclosure, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the graft polymer are styrene-equivalent values ​​measured by liquid chromatography, and the measurement conditions are as follows: Measurement device: Shimazu LC-20 system (Shimadzu Corporation) Column: TSK gel super 3000, 2000, 1000 Flow rate: 0.2 mL / min Mobile phase and sample solvent: tetrahydrofuran (contains stabilizer) Sample concentration: 0.05% Column temperature: 40°C Detector: differential refractometer (RI) Standard sample: polystyrene

[0027] The methanol-soluble matter contained in the polymer composition of the present disclosure is a component contained in the polymer composition during the graft polymerization of cellulose acetate and lactones. Thus, the methanol-soluble matter may include, for example, at least one of raw materials (cellulose acetate, lactones, catalyst, etc.) and by-products (homopolymers of lactones, etc.) used in the graft polymerization of cellulose acetate and lactones.

[0028] The methanol-soluble matter contained in the polymer composition of the present disclosure usually contains a homopolymer of a lactone, and from the viewpoint of suitably exerting the effects of the present disclosure, it preferably contains a homopolymer of a lactone.

[0029] That is, the polymer composition of the present disclosure is a composition containing a graft polymer of cellulose acetate and lactones and the methanol-soluble matter, and the graft polymer contains a portion graft-polymerized with lactones. The portion graft-polymerized with lactones of the graft polymer and the homopolymer of lactones contained in the methanol-soluble matter have high chemical affinity, which can suitably suppress bleeding out of the methanol-soluble matter from the polymer composition. Furthermore, the portion graft-polymerized with lactones of the graft polymer and the homopolymer of lactones contained in the methanol-soluble matter also contribute to enhancing the thermoplasticity of the polymer composition. Therefore, in the polymer composition of the present disclosure, it is preferable that the methanol-soluble matter contains a homopolymer of lactones from the viewpoint of achieving both excellent thermoplasticity and suppression of bleed-out.

[0030] The proportion of homopolymers of lactones contained in the methanol soluble matter is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, and still more preferably 70% by mass or more. The upper limit can be, for example, 100% by mass or less, 97% by mass or less, 94% by mass or less, or 91% by mass or less. Preferred ranges include 30 to 100% by mass, 30 to 97% by mass, 30 to 94% by mass, 30 to 91% by mass, 40 to 100% by mass, 40 to 97% by mass, 40 to 94% by mass, 40 to 91% by mass, 50 to 100% by mass, 50 to 97% by mass, 50 to 94% by mass, 50 to 91% by mass, and 60 to 100% by mass.

[0031] In the present disclosure, the type of lactone is not particularly limited as long as the effects of the present invention are exhibited, and examples thereof include β-propiolactone, δ-valerolactone, ε-caprolactone, α,α-dimethyl-β-propiolactone, β-ethyl-δ-valerolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ-methyl-ε-caprolactone, 3,3,5-trimethyl-ε-caprolactone, 3,5,5-trimethyl-ε-caprolactone, and enantholactone. Among these, ε-caprolactone is particularly preferred because it is industrially readily available, relatively inexpensive, and has excellent compatibility with cellulose acetate. The polymer composition of the present disclosure may use only one type of lactone, or two or more types of lactones.

[0032] As described below, it is preferable to use a catalyst when graft polymerizing cellulose acetate and lactones. When a catalyst is used, the catalyst may be contained in the methanol-soluble matter. The catalyst is not particularly limited as long as it is a compound that exhibits the function of promoting the graft polymerization reaction between cellulose acetate and lactones, and known catalysts can be used. In the present disclosure, it is preferable to use a phosphorus compound that is a weak acid, such as diphenyl phosphoric acid or bis(4-nitrophenyl) phosphate, as the catalyst. The catalyst used may be one type only or two or more types. When a catalyst is contained in the methanol-soluble matter, the catalyst contained in the methanol-soluble matter may be one type only or two or more types.

[0033] When a phosphorus compound is used as a catalyst in the production of the polymer composition of the present disclosure, the phosphorus compound is contained in the polymer composition of the present disclosure (particularly in the methanol-soluble matter). When the phosphorus compound is contained in the polymer composition of the present disclosure, the content of the phosphorus compound in the polymer composition of the present disclosure is preferably 400 ppm, more preferably 1000 ppm or more, and the upper limit is, for example, 50000 ppm or less, more preferably 30000 ppm.

[0034] In the present disclosure, it is also preferable not to use a catalyst containing a metal selected from Groups 4 and 14 of the periodic table as a catalyst when graft polymerizing cellulose acetate and lactones. If a catalyst containing these metals is not used in the production of the polymer composition of the present disclosure, these metals can be substantially absent from the polymer composition of the present disclosure (particularly, from the methanol-soluble matter). Specifically, "substantially absent" of these metals in the polymer composition of the present disclosure means that the content of metals selected from Groups 4 and 14 is 100 ppm or less.

[0035] The polymer composition of the present disclosure preferably does not contain acetylated wood flour. It is also preferable that the polymer composition of the present disclosure is not contained in a composition containing acetylated wood flour. It is also preferable that the graft polymer of cellulose acetate and lactones contained in the polymer composition of the present disclosure is not a graft polymer of acetylated wood flour and lactones.

[0036] The term "acetylated wood flour" refers to wood flour that has been acetylated. "Acetylation" refers to a process for introducing acetyl groups into wood flour, and is specifically defined as a chemical process for substituting hydrogen atoms of some hydroxyl groups (-OH) in wood flour with acetyl groups (-CO-CH). "Wood flour" refers to the entire wood flour obtained by shredding and / or grinding wood biomass as a raw material and chipping it. "Whole wood flour" means that the chipped wood flour has not been separated or fractionated into components such as lignin, hemicellulose, and cellulose. The cellulose acetate of the present disclosure differs from acetylated wood flour in that it is substantially free of lignin. Specifically, the term "substantially free of lignin" means that the lignin content of the cellulose acetate of the present disclosure is lower than that of the pulp raw material used as the raw material for cellulose acetate, for example, 10,000 ppm or less.

[0037] The thermal flow initiation temperature of the polymer composition of the present disclosure is preferably 200° C. or lower, more preferably 190° C. or lower, and even more preferably 180° C. or lower, and the lower limit is, for example, 100° C. or higher, preferably 110° C. or higher, and more preferably 120° C. or higher, and a preferred range is 120 to 180° C. The thermal flow initiation temperature of the polymer composition is measured by the method described in the examples.

[0038] Furthermore, the haze (500 μm thick, a PET film with high surface smoothness is used as a release film for the heat press) immediately after the polymer composition of the present disclosure is subjected to heat pressing under conditions of a temperature higher than the heat flow initiation temperature by 30° C. is preferably 50% or less, more preferably 30% or less, and even more preferably 10% or less. The lower limit is, for example, 0.1%, and preferred ranges include 0.1 to 50%, 0.1 to 30%, and 0.1 to 10%. Furthermore, when the polymer composition of the present disclosure is subjected to heat pressing under conditions of a temperature higher than the heat flow initiation temperature by 30°C and then allowed to stand for 20 hours in an environment at a temperature of 23°C and a relative humidity of 50%, it is preferable that the rate of change in haze (thickness: 500 μm) from immediately after heat pressing is small, and the rate of change is preferably 50% or less, more preferably 30% or less, and even more preferably 10% or less. The lower limit may be, for example, −1%, as transparency may improve over time, and preferred ranges include −1 to 50%, −1 to 30%, and up to −1 to 10%, etc. Furthermore, when the polymer composition of the present disclosure is subjected to heat pressing under conditions of a temperature above the heat flow initiation temperature + 30°C and then allowed to stand for 20 hours in an environment at a temperature of 65°C and a relative humidity of 20%, it is preferable that the rate of change in haze (thickness 500 μm) from immediately after heat pressing is small, and the rate of change is preferably 50% or less, more preferably 30% or less, and even more preferably 10% or less. The lower limit may be, for example, -1%, as transparency may improve over time, and preferred ranges include -1 to 50%, -1 to 30%, and up to -1 to 10%, etc. The method for measuring these hazes is as described in the Examples.

[0039] Furthermore, the total light transmittance (500 μm thick, a PET film with high surface smoothness is used as a release film for heat pressing) of the polymer composition of the present disclosure immediately after being subjected to heat pressing under conditions of a temperature of the heat flow initiation temperature +30° C. is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and still more preferably 85% or more. The upper limit can be, for example, 92%, 95%, or 100%. Preferred ranges include 70 to 100%, 70 to 95%, 70 to 92%, 75 to 100%, 75 to 95%, 75 to 92%, 80 to 100%, 80 to 95%, 80 to 92%, 85 to 100%, 85 to 95%, and 85 to 92%. Furthermore, when the polymer composition of the present disclosure is subjected to a heat press under conditions of a temperature of the heat flow initiation temperature +30°C and then allowed to stand for 20 hours in an environment at a temperature of 23°C and a relative humidity of 50%, the total light transmittance (thickness: 500 μm) is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and still more preferably 85% or more. The upper limit can be, for example, 92%, 95%, or 100%. Preferred ranges include 70 to 100%, 70 to 95%, 70 to 92%, 75 to 100%, 75 to 95%, 75 to 92%, 80 to 100%, 80 to 95%, 80 to 92%, 85 to 100%, 85 to 95%, and 85 to 92%. Furthermore, when the polymer composition of the present disclosure is subjected to a heat press under conditions of a temperature of the thermal flow initiation temperature +30°C and then allowed to stand for 20 hours in an environment at a temperature of 65°C and a relative humidity of 20%, the total light transmittance (thickness: 500 μm) is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and even more preferably 85% or more. The upper limit may be, for example, 92%, 95%, or 100%, and preferred ranges include 70 to 100%, 70 to 95%, 70 to 92%, 75 to 100%, 75 to 95%, 75 to 92%, 80 to 100%, 80 to 95%, 80 to 92%, 85 to 100%, 85 to 95%, and 85 to 92%. The method for measuring these total light transmittances is as described in the Examples.

[0040] The polymer composition of the present disclosure may contain additives such as colorants, stabilizers (ultraviolet absorbers, antioxidants, etc.), plasticizers, fillers (nanofillers, etc.), lubricants, antistatic agents, bluing agents, etc., depending on the purpose. When the polymer composition of the present disclosure contains additives, the additives may be of only one type, or two or more types.

[0041] The shape, size, etc. of the polymer composition of the present disclosure can be appropriately selected depending on the application of the polymer composition. Since the polymer composition of the present disclosure has thermoplasticity, it can be molded by molding means used in processing ordinary thermoplastic resins, such as injection molding, extrusion molding, press molding, etc.

[0042] The polymer composition of the present disclosure can be used in a wide variety of applications, such as sheets, films, pipes, rods, tools, tableware, packaging materials, electronic components, toys, containers, furniture, etc. Furthermore, the polymer composition of the present disclosure can be, for example, biodegradable. Furthermore, it is expected to be degradable in the ocean.

[0043] The method for producing the polymer composition of the present disclosure is not particularly limited, and for example, the method described in the section below titled "Method for producing polymer composition" can be suitably adopted.

[0044] [Method for Producing Polymer Composition] The method for producing a polymer composition according to the present disclosure includes a polymerization step of graft polymerizing cellulose acetate and lactones to obtain a polymer composition. Furthermore, the mass ratio of the cellulose acetate to the lactones mixed in the polymerization step is set to a range of 0.25 to 2.4 parts by mass of the lactones per part by mass of cellulose acetate. In the production method according to the present disclosure, by setting the ratio of the cellulose acetate to the lactones within a specific range in the graft polymerization reaction of the cellulose acetate and the lactones, a novel graft polymer composition can be provided that exhibits both excellent thermoplasticity and suppressed bleed-out.

[0045] That is, according to the method for producing a polymer composition of the present disclosure, it is possible to suitably produce a polymer composition of the present disclosure in which the proportion of methanol-soluble matter measured by the above-mentioned method is in the range of 13 mass% or more and 33 mass% or less.

[0046] In the method for producing a polymer composition according to the present disclosure, the degree of acetyl substitution (DS) of cellulose acetate used as a raw material, the degree of molar substitution (MS) of lactones per glucose unit, the type of lactones used as a raw material, the type of catalyst, and the like are as described above in the section [Polymer composition].

[0047] A solvent may be used in the polymerization step. The solvent is not particularly limited as long as it does not inhibit the graft polymerization reaction between cellulose acetate and lactones, and organic solvents such as toluene and cyclohexanone can be used. Only one type of solvent may be used in the polymerization step, or two or more types of solvents may be used. After the polymerization step, it is preferable to remove the solvent from the product. However, when removing the solvent, care must be taken to ensure that the proportion of the methanol-soluble matter contained in the polymer composition does not fall outside the range of 13% by mass or more and 33% by mass or less.

[0048] In the method for producing a polymer composition according to the present disclosure, the mass ratio of the cellulose acetate to the lactones mixed in the polymerization step may be set in the range of 0.25 to 2.4 parts by mass of the lactones per part by mass of cellulose acetate. From the viewpoint of more suitably exhibiting the effects of the present disclosure, the amount of the lactones is preferably 0.25 parts by mass or more, more preferably 0.30 parts by mass or more, even more preferably 0.35 parts by mass or more, and is preferably 2.4 parts by mass or less, more preferably 2.0 parts by mass or less, even more preferably 1.5 parts by mass or less; preferred ranges include 0.25 to 2.4 parts by mass, 0.25 to 2.0 parts by mass, 0.25 to 1.5 parts by mass, 0.30 to 2.4 parts by mass, 0.30 to 2.0 parts by mass, 0.30 to 1.5 parts by mass, 0.35 to 2.4 parts by mass, 0.35 to 2.0 parts by mass, and 0.35 to 1.5 parts by mass.

[0049] In the present disclosure, the proportion of methanol soluble matter in the polymer composition can be adjusted to a range of 13% by mass or more and 33% by mass or less by further providing a purification step after the polymerization step, but in the production method of the present disclosure, the proportion of methanol soluble matter can be adjusted to a range of 13% by mass or more and 33% by mass or less by setting the mass ratio of cellulose acetate to lactones within the above-mentioned predetermined range, so it is also preferable not to provide a purification step. As described above, the production method of the present disclosure does not require a purification step after the polymerization step, and is a production method that is preferred from the environmental and cost perspectives.

[0050] Furthermore, from the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the amount of catalyst used is, relative to 100 parts by mass of the total amount of cellulose acetate and lactones, preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, even more preferably 0.3 parts by mass or more, and is preferably 5.0 parts by mass or less, more preferably 4.5 parts by mass or less, even more preferably 4.0 parts by mass or less. Preferred ranges include 0.1 to 5.0 parts by mass, 0.1 to 4.5 parts by mass, 0.1 to 4.0 parts by mass, 0.2 to 5.0 parts by mass, 0.2 to 4.5 parts by mass, 0.2 to 4.0 parts by mass, 0.3 to 5.0 parts by mass, 0.3 to 4.5 parts by mass, and 0.3 to 4 parts by mass.

[0051] The reaction temperature in the polymerization step is preferably 60°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher, and is preferably 230°C or lower, more preferably 220°C or lower, and even more preferably 210°C or lower. Preferred ranges include 60 to 230°C, 60 to 220°C, 60 to 210°C, 65 to 230°C, 65 to 220°C, 65 to 210°C, 70 to 230°C, 70 to 220°C, and 70 to 210°C.

[0052] The reaction time in the polymerization step is preferably 2 minutes or more, more preferably 3 minutes or more, and even more preferably 4 minutes or more, and is preferably 60 minutes or less, more preferably 30 minutes or less, and even more preferably 15 minutes or less. Preferred ranges include 2 to 60 minutes, 2 to 30 minutes, 2 to 15 minutes, 3 to 60 minutes, 3 to 30 minutes, 3 to 15 minutes, 4 to 60 minutes, 4 to 30 minutes, and 4 to 15 minutes.

[0053] In the heavy-duty process, it is desirable to thoroughly dry the cellulose acetate and lactones used as raw materials. The polymerization process is preferably carried out in an inert gas environment, such as nitrogen gas or argon gas. In the polymerization process, it is also desirable to stir the cellulose acetate and lactones used as raw materials, as well as the catalyst, solvent, etc. Stirring can be carried out using a kneader, such as a Labo Plastomill or a twin-screw extruder.

[0054] The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mn / Mw) of the polymer composition produced by the method of the present disclosure are exemplified by the same descriptions as those exemplified in the above-mentioned section [Polymer composition].

[0055] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0056] Examples 1-4 and Comparative Examples 1-10 (Production of Polymer Composition) Dried cellulose diacetate (degree of acetyl substitution (DS) 2.1, weight average molecular weight 100,000, number average molecular weight 170,000) and ε-caprolactone were prepared. 45 g of cellulose diacetate was pulverized using an Absolute Mill ABS-W (manufactured by Osaka Chemical Co., Ltd.) at 16,800 rpm for 2 minutes and 30 seconds. Next, the pulverized cellulose diacetate (CDA) was thoroughly dried. ε-caprolactone (εCL) was also thoroughly dried. Next, cellulose diacetate (CDA) and ε-caprolactone (εCL) were mixed in a beaker at a total weight ratio of 25 g as shown in Table 1, and then placed in a batch mixer (Toyo Seiki Seisaku-sho, Ltd., Labo Plastomill (C Model) 4C150) and stirred for 10 minutes (dissolution step). Next, 2.4 mL of a toluene solution (0.2 g / mL) of diphenyl phosphate (DPP) as a catalyst was added (the catalyst amount was 2% by mass relative to the total amount of cellulose diacetate (CDA) and ε-caprolactone (εCL)). Graft polymerization of cellulose diacetate (CDA) and ε-caprolactone (εCL) was performed, and a polymer composition (unpurified product) containing a graft polymer of cellulose diacetate (CDA) and ε-caprolactone (εCL) was obtained. The obtained polymer compositions (unpurified products) were subjected to measurement of the proportion of methanol-soluble matter and the molar substitution (MS) of ε-caprolactone (εCL), as described below, and further to measurement of the haze, total light transmittance, and heat flow onset temperature after heat pressing, to evaluate the inhibition of bleedout and thermoplasticity. The results are shown in Table 1.

[0057] The particle size distribution of the pulverized cellulose diacetate was measured using a Beckman Coulter laser diffraction particle size distribution analyzer (LS 13 320 XR) in a state where the cellulose diacetate was dispersed in water. The particle size distribution results are shown in Figure 1.

[0058] (Ratio of Methanol Soluble Matter) Under atmospheric pressure and in a 20°C environment, 24 g of the polymer composition was dissolved in 144 ml of acetone, 1.5 L of methanol was added, and the mixture was stirred for 12 hours. The resulting mixture was filtered through a PTFE membrane filter (T100A047A manufactured by ADVANTEC Corporation, the same applies hereinafter) with a pore size of 1 μm, and the filtrate was collected. The resulting filtrate was again poured into 0.5 L of methanol and stirred for 1 hour. The resulting mixture was filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and filtrate were collected. The resulting filtrate was again poured into 0.5 L of methanol and stirred for 1 hour. The resulting mixture was filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and filtrate were collected. After confirming that the pH of the filtrate was 7, the filtrate was added to 1 L of methanol and stirred for 12 hours. If the pH of the filtrate is not 7, the obtained filtrate is again poured into 0.5 L of methanol and stirred for 1 hour. The resulting mixture is filtered through a PTFE membrane filter having a pore size of 1 μm, and the filtrate and filtrate are collected. This operation is repeated until the pH of the filtrate is confirmed to be 7. The resulting mixture is filtered through a PTFE membrane filter having a pore size of 1 μm, and the filtrate is collected. The obtained filtrate is vacuum dried at 40° C. for 12 hours to obtain a dry mass. The proportion of methanol-soluble matter contained in the polymer composition is calculated from the dry masses of the polymer composition before purification and the polymer composition after purification. Methanol-soluble component of polymer composition = dry mass of polymer composition before purification - dry mass of polymer composition after purification Proportion of methanol-soluble component contained in polymer composition = (mass of methanol-soluble component of polymer composition) / dry mass of polymer composition after purification × 100 (mass%)

[0059] (Proportion of Lactone Homopolymer in Methanol-Soluble Substance) For each of the obtained polymer compositions (unpurified), the caprolactone homopolymer in the methanol-soluble substance was measured by the following method. The results are shown in Table 1. The polymer composition (purified) was dissolved in deuterated chloroform and subjected to 1H NMR measurement. If the polymer composition is insoluble in deuterated chloroform, trifluoroacetic acid may be used in combination. The sample concentration was 10 mg / mL, and the measurement was performed under the conditions of an observation time of 0.15 seconds, a relaxation time of 1.0 seconds, an observation frequency of 300.1 MHz, and 16 accumulations. The chemical shift values ​​of the obtained spectrum were expressed in ppm, with the peak of the methyl group of the internal standard trimethylsilane (TMS) as the reference (0 ppm).

[0060]

[0061] The composition ratio of unreacted caprolactone to cellulose acetate in the resulting polymer composition (unpurified product) was determined from the peak area of ​​H(d) in the unreacted caprolactone (chemical shift: 1.75 to 1.8 ppm), and the proportion of caprolactone homopolymer in the methanol soluble matter was calculated by the following formula.

[0062] Caprolactone homopolymer (mass) in methanol soluble matter = methanol soluble component (mass) of polymer composition - unreacted caprolactone (mass) - charged catalyst (mass) Proportion of caprolactone homopolymer in methanol soluble matter = mass of caprolactone homopolymer in methanol soluble matter / mass of methanol soluble matter of polymer composition × 100 (mass %)

[0063] (Molar Substitution (MS) of εCL) For each of the obtained polymer compositions (purified products), the molar substitution (MS) of the lactones per glucose unit of cellulose acetate was measured by the following method. The results are shown in Table 1. The polymer compositions (purified products) were dissolved in deuterated chloroform and subjected to 1H NMR measurement. If the polymer composition is insoluble in deuterated chloroform, trifluoroacetic acid may be used in combination. The sample concentration was 10 mg / mL, and the measurement was performed under the conditions of an observation time of 0.15 seconds, a relaxation time of 1.0 seconds, an observation frequency of 300.1 MHz, and 16 accumulations. The chemical shift values ​​of the obtained spectra were expressed in ppm, with the peak of the methyl group of the internal standard trimethylsilane (TMS) as the reference (0 ppm). All measurements were performed using a 300-MHz NMR apparatus (INOVA300 manufactured by Varian). The molar substitution (MS) of the polymer compositions (purified products) was calculated using the following formula from the 1H NMR measurement results. Here, MS is defined as the number of moles of caprolactone introduced per mole of AGU.

[0064]

[0065] Chemical shift of the acetyl group peak area: 1.90 to 2.15 ppm Chemical shift of the H2″ peak area: 2.15 to 2.40 ppm Chemical shift of the H4″ peak area: 1.3 to 1.5 ppm

[0066] (Heat flow initiation temperature (thermoplasticity evaluation)) The heat flow initiation temperature of each polymer composition (unrefined product) was measured using a flow tester. The heat flow initiation temperature was measured by a temperature rising method using a constant test force capillary tube rheometer and a flow tester CFT-500EX manufactured by Shimadzu Corporation. The measurement conditions were as follows. The results are shown in Table 1. Sample: 1.0-1.1 g Load: 50 kgf Die dimensions: diameter 1.0 mm, length 1.0 mm Plunger area: 1 cm 2 Preheating time: 120 seconds Starting temperature: 50°C Heating rate: 5.0°C / min

[0067] Furthermore, the filtered products obtained in the above (ratio of methanol soluble matter) were each used as polymer compositions (purified products), and the thermal flow initiation temperatures were measured in the same manner. The results are shown in Table 1.

[0068] (Haze and Total Light Transmittance) After measuring the heat flow initiation temperature at the (heat flow initiation temperature) mentioned above, the transparency (haze and total light transmittance) of each polymer composition (unpurified) in film form was measured. Approximately 1.7 g of the polymer composition (unpurified) was weighed, and the gap (5 cm square) of a 0.5 mm thick metal spacer was sandwiched between two aluminum foil sheets or PET sheets as shown in Table 1. This was then sandwiched between two metal plates and thermo-pressed into a film using a Mini Test Press MP-WNL manufactured by Toyo Seiki Seisaku-sho, Ltd. The pressing temperature was the heat flow initiation temperature measured above + 30°C, and the value obtained with a flow tester was used as the heat flow initiation temperature. The thermo-pressing was performed by pressurizing from 0 MPa for 1 minute, then increasing the pressure to 3.4 MPa (gauge pressure, the same applies below) over 2 minutes, leaving it to stand for 30 seconds, and then increasing the pressure to 10.2 MPa and maintaining the pressure for 30 seconds. Thereafter, a cold press (Mini Test Press MP-SC manufactured by Toyo Seiki Seisakusho) was used to apply the same pressure as that used during hot pressing for 3 minutes to obtain a film of the polymer composition (unpurified product) (thickness 500 μm immediately after hot pressing). To evaluate the transparency of the obtained film (immediately after hot pressing), a haze meter (Nippon Denshoku Industries Co., Ltd. Haze Meter NDH4000) was used to measure the haze (HZ) (%) and total light transmittance (TT) (%). The measured values ​​were averaged over three measurements with different measurements.

[0069] Furthermore, the films obtained in Examples 1 to 4 and Comparative Examples 5, 7, and 9 (immediately after heat pressing) were left to stand in a 23°C, 50% RH environment for 20 hours (thickness: 500 μm after heat pressing), and the film obtained in Example 3 (immediately after heat pressing) was left to stand in a 65°C, 20% RH environment for 20 hours (thickness: 500 μm after heat pressing). The haze (HZ) (%) and total light transmittance (TT) (%) were measured for each film in the same manner. As bleed-out progresses over time after heat pressing, the film becomes cloudy (the haze value increases). Therefore, the susceptibility of the polymer composition (unpurified product) to bleed-out can be evaluated by the change in haze. Table 1 shows the percentage change in haze after each setting, based on the haze (HZ) (%) of the film immediately after heat pressing.

[0070] Furthermore, the films obtained in Examples 1 to 4 and Comparative Examples 5, 7, and 9 (immediately after heat pressing) were left to stand in a room (room temperature in the range of 5 to 24°C) without temperature control for 110 hours after heat pressing, and the change rate (%) of haze (HZ) and total light transmittance (TT) (%) were measured in the same manner. The results are shown in Table 1.

[0071]

Claims

1. A polymer composition comprising a graft polymer of cellulose acetate and lactones, wherein the polymer composition has a methanol-soluble matter content, measured by the following method, in the range of 13% by mass or more and 33% by mass or less. (Method for measuring the methanol-soluble matter content): At atmospheric pressure and 20°C, 24 g of the polymer composition is dissolved in 144 ml of acetone, 1.5 L of methanol is added, and the mixture is stirred for 12 hours. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate is recovered. The resulting filtrate is again added to 0.5 L of methanol and stirred for 1 hour. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and filtrate are recovered. The resulting filtrate is again added to 0.5 L of methanol and stirred for 1 hour. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate and filtrate are recovered. After confirming that the pH of the filtrate is 7, the filtrate is added to 1 L of methanol and stirred for 12 hours. The resulting mixture is filtered through a PTFE membrane filter with a pore size of 1 μm, and the filtrate is recovered. The resulting filtrate is vacuum dried at 40° C. for 12 hours to obtain a dry mass. The proportion of methanol-soluble matter contained in the polymer composition is calculated from the dry masses of the polymer composition before and after purification. Methanol-soluble component of polymer composition = dry mass of polymer composition before purification - dry mass of polymer composition after purification Proportion of methanol-soluble matter contained in polymer composition = (mass of methanol-soluble component of polymer composition) / dry mass of polymer composition after purification × 100 (mass%) 2. The polymer composition according to claim 1, wherein the methanol-soluble matter in the polymer composition is a homopolymer of lactones.

3. The polymer composition according to claim 2, wherein the methanol-soluble matter contains homopolymers of lactones in an amount of 60% by mass or more.

4. The polymer composition according to any one of claims 1 to 3, wherein the lactones include ε-caprolactone.

5. The polymer composition according to any one of claims 1 to 3, wherein the cellulose acetate has a degree of acetyl substitution (DS) of 1.0 to 2.

9.

6. The polymer composition according to any one of claims 1 to 3, wherein the molar substitution (MS) of the lactones per glucose unit of the cellulose acetate is 0.1 to 5.

7. The polymer composition according to any one of claims 1 to 3, wherein the methanol-soluble matter in the polymer composition is a phosphorus compound.

8. A method for producing a polymer composition, comprising a polymerization step of graft-polymerizing cellulose acetate and lactones to obtain a polymer composition, wherein the mass ratio of the cellulose acetate to the lactones mixed in the polymerization step is in the range of 0.25 to 2.4 parts by mass per part by mass of the cellulose acetate.

9. The method for producing a polymer composition according to claim 8, wherein the polymer composition contains a homopolymer of the lactone.

10. The method for producing a polymer composition according to claim 8 or 9, wherein the lactones include ε-caprolactone.

11. The method for producing a polymer composition according to claim 8 or 9, wherein the cellulose acetate has a degree of acetyl substitution (DS) of 1.0 to 2.

9.

12. The method for producing a polymer composition according to claim 8 or 9, wherein the molar substitution (MS) of the lactone per glucose unit of the cellulose acetate is 0.1 to 5.

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