JP2006036954A - Polycarbonate composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new polycarbonate that includes the parts derived from renewable resources and shows more suppressed decomposition properties than that of the conventional polycarbonate. <P>SOLUTION: This polycarbonate composition is produced by adding cellulose to a polycarbonate including a specific aliphatic alkylene glycol residual group and ether diol residual group and melt-kneading the mixture. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to polycarbonate compositions containing moieties that can also be derived from renewable resources.

  Polycarbonate is generally produced using raw materials obtained from petroleum resources. However, there is concern about the exhaustion of petroleum resources, and there is a demand for production of polymers using raw materials obtained from renewable resources such as plants. The ether diol shown in (2) is easily made from renewable resources such as sugars and starch, and three stereoisomers are known.

  Specifically, 1,4: 3,6-dianhydro-D-sorbitol (hereinafter sometimes abbreviated as “isosorbide”) represented by formula (3), 1,4: represented by formula (4). 3,6-dianhydro-D-mannitol (hereinafter sometimes abbreviated as “isomannide”), 1,4: 3,6-dianhydro-L-iditol (hereinafter “isoidid”) represented by the formula (5) And isosorbide, isomannide, and isoidide are obtained from D-glucose, D-mannose, and L-idose, respectively. For example, isosorbide can be obtained by hydrogenating D-glucose and then dehydrating it using an acid catalyst.

Aliphatic polycarbonates are also known as polycarbonates. Among the ether diols described above, in particular, incorporation into polycarbonate using isosorbide as a monomer has been studied (Patent Document 1, Non-Patent Document 1, (See 2, 3 etc.).
For example, a method for producing a copolycarbonate of isosorbide and various diphenols has been reported (see, for example, Patent Document 2, Non-Patent Documents 4, 5, and 6), but these raw materials are only petroleum. Have a problem.

On the other hand, for polycarbonates derived from aliphatic diols, the glass transition of polycarbonates derived from ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,10-decanediol. The temperatures are 0 to 5 ° C., −35 ° C., −41 ° C., and −50 ° C., respectively (see, for example, Non-Patent Documents 7 and 8).
Polycarbonates derived from these aliphatic diols are usually oily or low-melting solids at room temperature because of their flexible structure, and are not suitable for use as general-purpose plastics.

In order to solve these problems, development of a polycarbonate composed of isosorbide and an aliphatic diol, which is excellent in molding processability and heat resistance, is in progress.
One of them is a copolymerized polycarbonate of an aliphatic diol such as 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and isosorbide (Non-patent Document 9, 10 etc.).
However, since these are more easily biodegradable than petroleum-derived polycarbonate, there has been a problem in application to applications where they are exposed to an environment that is easily biodegraded (see Non-Patent Document 10).

German Patent Application No. 2938464 (Claims) Japanese Patent Laid-Open No. 56-110723 (Claims) “Journal future praktische Chemie”, 1992, 334, p. 298-310 “Macromolecules”, 1996, Vol. 29, p. 8077-8082 “Journal of Applied Polymer Science” (2002, Volume 86), p. 872-880 “Macromolecular Chemistry and Physics” 1997, Vol. 198, p. 2197-2210 “Journal of Polymer Science: Part A”, 1997, Vol. 35, p. 1611-1619 “Journal of Polymer Science: Part A”, 1999, vol. 37, p. 1125 to 1133 “Journal of Polymer Science; Polymer Letters Edition” (“Journal of Polymer Science: Polymer Letters Edition”), 1980, Vol. 18, p. 599-602 “Macromolecular Chemistry and Physics” 1998, 199, p. 97-102 Okada et al., Ministry of Education, Culture, Sports, Science and Technology Grant-in-Aid for Scientific Research (B) “Environmentally low load polymer” Construction of sustainable material system based on production of environmentally low load plastic from renewable resources Shu, 2002, p. 26-29 "Journal of Polymer Science: Part A", 2003, vol. 41, p. 2312-2321

  An object of the present invention is to provide a novel polycarbonate containing a part that can be derived from renewable resources and having a degradability suppressed as compared with the present aliphatic polycarbonate.

  In light of the above prior art, the present inventors have made extensive studies and, in particular, have studied the biodegradability of polycarbonate, and as a result, further contain cellulose in a polycarbonate copolymerized with an ether diol typified by isosorbide and an aliphatic diol. As a result, it was found that a polycarbonate composition with suppressed biodegradability was obtained, and further studies were made to complete the present invention.

That is, the object of the present invention is a polycarbonate comprising cellulose and a polycarbonate comprising an aliphatic alkylene glycol residue represented by the following general formula (a) and an ether diol residue represented by the following structural formula (1). Achieved by the composition.

  According to the present invention, a polycarbonate composition with suppressed biodegradability can be obtained by copolymerizing an ether diol represented by isosorbide and an aliphatic diol and then kneading cellulose.

Hereinafter, the present invention will be described in more detail.
The polycarbonate according to the present invention comprises an aliphatic alkylene glycol residue represented by the following general formula (a) and an ether diol residue represented by the following structural formula (1).

  That is, the obtained polycarbonate has a repeating unit part of the following formula (6) and a repeating unit part of the following formula (7).

  Here, the ether diol residue represented by the structural formula (1) preferably occupies 65 to 98% by weight in all diol residues, and further occupies 80 to 98% by weight in all diol residues. It is preferable.

  When the content of the ether diol is less than this range, the viscosity of the resulting resin is lowered and a brittle polymer is obtained. On the other hand, when the content of ether diol exceeds this range, the glass transition temperature and the melt viscosity become very high, and the molding process becomes difficult.

  The ether diol used in the polycarbonate according to the present invention has the structure of the following structural formula (2), and is represented by structural formulas (3), (4) and (5), respectively, such as isosorbide, isomannide, and isoidide. Are known. These saccharide-derived ether diols are substances obtained from natural biomass and are one of so-called renewable resources.

  Isosorbide is obtained by hydrogenating D-glucose obtained from starch and then dehydrating it. Other ether diols can be obtained by the same reaction except for the starting materials.

  In particular, a polycarbonate containing an isosorbide residue as a saccharide-derived ether diol residue using isosorbide as one of the raw materials is preferable. Isosorbide is an ether diol that can be easily made from starch, etc., and can be obtained in abundant resources. In addition, it is superior in ease of manufacture, properties, and wide range of applications compared to isomannide and isoidide. .

  The polycarbonate according to the present invention preferably has a glass transition temperature of at least 80 ° C or higher. The glass transition temperature is important for the heat resistance and melt moldability of the molded product, and is preferably 100 ° C. or higher and 160 ° C. or lower in order to maintain practically sufficient heat resistance and moldability.

  Examples of the carbonic acid diester used in the polycarbonate production method according to the present invention include diphenyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Diphenyl carbonate is preferred.

  The polycarbonate composition according to the present invention can be polymerized by, for example, a method using carbonyl halide such as phosgene as a starting material, a method using carbonate ester as a starting material, a method using carbon dioxide or carbonate as a starting material, and the like. In view of environmental problems, the melt polymerization method is preferable.

  In the melt polymerization method according to the present invention, the raw material diol and carbonic acid diester are heated at normal pressure in the presence of a polymerization catalyst, preliminarily reacted, and then stirred while heating at a temperature of 280 ° C. or lower under reduced pressure. To distill the phenol produced. The diol as the raw material contains at least the ether diol represented by the formula (2). The system is preferably maintained in an atmosphere of a gas inert to the raw materials such as nitrogen, reaction mixture, and reaction products. Examples of inert gases other than nitrogen include argon.

  The reaction at normal pressure at the beginning of the reaction is to proceed with the oligomerization reaction, and when the phenol is distilled off by reducing the pressure later in the reaction, the unreacted monomer distills out, the molar balance is lost, and the degree of polymerization decreases Is to prevent. In the production method according to the present invention, the reaction can be advanced by appropriately removing phenol from the system (reactor). For that purpose, it is effective and preferable to reduce the pressure.

  In the polymerization method according to the present invention, it is preferable to use conditions as low as possible in order to suppress the decomposition of the ether diol and obtain a highly viscous resin with little coloration. It is preferable that it is the range of 180 degreeC or more and 280 degrees C or less, More preferably, it is the range of 230 degreeC or more and 260 degrees C or less.

  In the production method according to the present invention, it is preferable to use a catalyst. Catalysts that can be used are (i) nitrogen-containing basic compounds, (ii) alkali metal compounds (iii) alkaline earth metal compounds, and the like. One of these may be used independently, or a plurality of these may be used. The combination of (i) and (ii) or (i) and (iii) or (i), (ii) and (iii) is often preferred.

  (I) is preferably tetramethylammonium hydroxide, and (ii) is preferably a sodium salt, and it is particularly preferable to use 2,2-bis (4-hydroxyphenyl) propane disodium salt.

  Cellulose according to the present invention can be used regardless of the degree of crystallinity, but cellulose derivatives such as cellulose diacetate and cellulose triacetate are less preferred.

  The cellulose according to the present invention is preferably used after being pulverized in the presence of polyethylene glycol. The polyethylene glycol used preferably has a molecular weight of 200-2 million.

  The cellulose kneading according to the present invention is preferably mixed little by little with the polycarbonate according to the present invention in a molten state.

  According to the present invention, it is possible to provide a novel polycarbonate containing a part that can be derived from renewable resources and having a degradability suppressed as compared with the present aliphatic polycarbonate.

Next, embodiments relating to the present invention will be described in detail. Various evaluation items were obtained as follows. The physical properties are summarized in Table 1.
(1) Biodegradation test To 200 g of commercially available humus (Sanyo bark (bare) bark compost) was added using 1 liter of water from a pond and aerated in a hot water bath at about 30 ° C. for 30 minutes or more. This solution was filtered through a filter paper and dissolved in 1 liter of ion-exchanged water for solution A for optimization test culture (37.5 g of potassium dihydrogen phosphate, 72.9 g of disodium hydrogen phosphate and 2.0 g of ammonium chloride). The total amount was adjusted to 2 liters, placed in a constant temperature bath at 50 ° C. close to the composting conditions, and compressed air was circulated at an air flow rate of 200 ml / min. Every 3-4 days, half of the culture broth was replaced with a freshly prepared one.

  About 200 mg of cast film (unstretched film) formed into a uniform thickness was cut out, put into a commercially available non-woven bag, put into the above container, taken out every one month, and the change in weight was examined. .

[Example 1]
23.4 g of isosorbide, 4.7 g of 1,6-hexanediol and 42.8 g of diphenyl carbonate are placed in a three-necked flask, and tetramethylammonium hydroxide and 2,2-bis (4-hydroxyphenyl) propane disodium salt are used as polymerization catalysts. Was melted at 180 ° C. in a nitrogen atmosphere.
Under stirring, the pressure in the reaction vessel was reduced to 13.3 kPa, and the reaction was performed for 20 minutes while distilling off the produced phenol. Next, after raising the temperature to 200 ° C., the pressure was gradually reduced, the reaction was carried out at 4.00 kPa for 25 minutes while distilling off the phenol, and the temperature was further raised to 215 ° C. for 10 minutes.
Then, the pressure was gradually reduced, and the reaction was continued at 2.67 kPa for 10 minutes and 1.33 kPa for 10 minutes. Further, when the pressure was reduced and reached 40 Pa, the temperature was gradually raised to 230 ° C., and reached 230 ° C. The reaction was allowed for 10 minutes.
Next, 3 g of low crystalline cellulose was added little by little and kneaded for 1 hour. A biodegradation test was performed on a film formed using this polymer.

[Example 2]
23.4 g of isosorbide, 4.7 g of 1,6-hexanediol and 42.8 g of diphenyl carbonate are placed in a three-necked flask, and tetramethylammonium hydroxide and 2,2-bis (4-hydroxyphenyl) propane disodium salt are used as polymerization catalysts. Was melted at 180 ° C. in a nitrogen atmosphere.
Polymerization was carried out in the same manner as in Example 1 and allowed to react for 10 minutes after reaching 230 ° C., 9 g of low crystalline cellulose was added little by little and kneaded for 1 hour. A biodegradation test was performed on a film formed using this polymer.

[Example 3]
23.4 g of isosorbide, 4.7 g of 1,6-hexanediol and 42.8 g of diphenyl carbonate are placed in a three-necked flask, and tetramethylammonium hydroxide and 2,2-bis (4-hydroxyphenyl) propane disodium salt are used as polymerization catalysts. Was melted at 180 ° C. in a nitrogen atmosphere.
Polymerization was carried out in the same manner as in Example 1 and allowed to react for 10 minutes after reaching 230 ° C. Then, 9 g of microcrystalline cellulose was added little by little and kneaded for 1 hour. A biodegradation test was performed on a film formed using this polymer.

[Example 4]
10 g of microcrystalline cellulose and 2 g of polyethylene glycol having a molecular weight of 2 million, which were vacuum-dried for 24 hours, were put into an experimental planetary rotary pot mill LA-PO. 1 was put into a reaction vessel and pulverized for 1 hour at 400 rpm (this is referred to as a pulverized cellulose product).
23.4 g of isosorbide, 4.7 g of 1,6-hexanediol and 42.8 g of diphenyl carbonate are placed in a three-necked flask, and tetramethylammonium hydroxide and 2,2-bis (4-hydroxyphenyl) propane disodium salt are used as polymerization catalysts. Was melted at 180 ° C. in a nitrogen atmosphere.
Polymerization was carried out in the same manner as in Example 1 and allowed to react for 10 minutes after reaching 230 ° C. Then, 3 g of the pulverized cellulose was added little by little and kneaded for 1 hour. A biodegradation test was performed on a film formed using this polymer.

[Comparative Example 1]
23.4 g of isosorbide, 4.7 g of 1,6-hexanediol and 42.8 g of diphenyl carbonate are placed in a three-necked flask, and tetramethylammonium hydroxide and 2,2-bis (4-hydroxyphenyl) propane disodium salt are used as polymerization catalysts. Was melted at 180 ° C. in a nitrogen atmosphere.
Polymerization was carried out in the same manner as in Example 1, the temperature was raised to 230 ° C., and the reaction was finally carried out at 250 ° C. and 66.6 Pa for 1 hour. A biodegradation test was performed on a film formed using this polymer.

[Comparative Example 2]
23.4 g of isosorbide, 4.7 g of 1,6-hexanediol and 42.8 g of diphenyl carbonate are placed in a three-necked flask, and tetramethylammonium hydroxide and 2,2-bis (4-hydroxyphenyl) propane disodium salt are used as polymerization catalysts. Was melted at 180 ° C. in a nitrogen atmosphere.
Polymerization was carried out in the same manner as in Example 1 and allowed to react for 10 minutes after reaching 230 ° C. Then, 3 g of low crystalline cellulose diacetate was added little by little and kneaded for 1 hour. A biodegradation test was performed on a film formed using this polymer.

Claims (5)

A polycarbonate composition comprising cellulose and a polycarbonate comprising an aliphatic alkylene glycol residue represented by the following general formula (a) and an ether diol residue represented by the following structural formula (1).

  The polycarbonate composition according to claim 1, wherein the cellulose is pulverized in the presence of polyethylene glycol.   The polycarbonate composition according to claim 1, wherein the ether diol residue represented by the structural formula (1) accounts for 65 to 98% by weight in the total diol residues.   The polycarbonate composition according to claim 1, wherein the cellulose occupies 0.5 to 60% by weight based on the polycarbonate. Cellulose is further added to a molten polycarbonate obtained by polymerizing an aliphatic alkylene glycol represented by the following general formula (b), an ether diol represented by the following structural formula (2) and a carbonic acid diester by a melt polymerization method. A method for producing a polycarbonate composition, which is then melt-kneaded.