JPH11209482A - Biodegradable film and sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable cellulose acetate film or sheet from a cellulose acetate resin having excellent biodegradability and melt extrusion moldability. SOLUTION: The objective film or sheet is prepd. by melt extruding a biodegradable compsn. which mainly comprises 60-80 wt.% cellulose acetate having a degree of acetylation of 56 % or lower and 20-40 wt.% at least one plasticizer selected from among biodegradable polyesters and their derivs., having an average mol.wt. in the range of 800-5,000, and contg. less than 5 wt.% component having a mol.wt. of 300 or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a biodegradable cellulose acetate film obtained by melt-extrusion with high productivity using a biodegradable cellulose acetate composition containing cellulose acetate and a plasticizer as main components. It is about a sheet.

[0002]

2. Description of the Related Art In recent years, with the growing awareness of environmental protection, the problem of treating plastic waste has been emphasized, and synthetic resins are used for agricultural and horticultural applications, which are formed into films and sheets by melt extrusion using raw materials. In addition, for disposable applications that are made into a nonwoven fabric by fiberization by melt spinning, use of a biodegradable resin that can be composted as a raw material is increasing. Under these circumstances, various biodegradable polyester resins have been developed for use in melt extrusion and melt spinning, but have not been widely used because of their high prices.

[0003] On the other hand, polysaccharides made from natural products are expected to be biodegradable and safe, and in addition to being inexpensive and capable of providing a stable supply of raw materials. Of good quality has not been obtained. Among the conventionally proposed polysaccharides, cellulose acetate widely used as a general-purpose resin using cellulose as a raw material is manufactured by partially saponifying cellulose after complete acetylation, and in recent years, Among them vinegar degree 5
It has become known that less than 6% is inherently biodegradable.

However, cellulose acetate is difficult to mold by melt extrusion because its melting point and thermal decomposition temperature are close to each other. Therefore, it is usually used as a composition to which a plasticizer is added. However, plasticizers that can be used are limited in terms of compatibility due to the high polarity of cellulose acetate, and generally have high volatility near the molding processing temperature. For example, using a cellulose acetate resin with a phthalate ester as a plasticizer, which is a typical plasticizer, is formed into a film or sheet by melt extrusion, and has a large amount of volatile components, and the plasticizer volatilized directly and through a cooling roll or the like. It has been known that the film moves to the film surface or sheet surface, and when the film or sheet is wound up, blocking occurs or the surface becomes cloudy. For this reason, heating the cooling roll is considered to be an effective means, but has not yet solved this problem. Also, if there are many volatile components,
It undesirably stains the die of the forming apparatus and stably operates.

Further, if the plasticizer is limited in terms of biodegradability, it is described in aliphatic esters such as triacetin and triethylsilate or JP-B-43-16305 and JP-A-8-53575. Only aliphatic polyesters, polyethers and the like having a molecular weight of hundreds to thousands are known. Among them, triacetin, a film formed by melt extrusion using an aliphatic ester such as triethylsilate as a plasticizer, and formed into a sheet, volatilized directly and through a cooling roll, etc., as in the case of the phthalate ester system due to the large amount of volatile components. The plasticizer moves to the surface of the film or sheet, and blocking occurs when the film or sheet is wound up.

When a polyester having a molecular weight of several hundreds to several thousands is used, the volatile component is small, but one end is a carboxyl group, so that it reacts with a hydroxyl group of cellulose acetate to have a viscosity during kneading and melt extrusion. It is not preferable because it becomes high or the fluidity is lost. In addition, when polyether is used, it does not cause blocking immediately after winding because the volatile component is small, but the hydrophilicity of the film and sheet increases, so that it can be used only for special purposes, and the plasticizer migrates to the film surface. If left for a long time, blocking will occur.

On the other hand, as a biodegradable cellulose ester composition, JP-A-7-76632 discloses that cellulose ester alone or a combination thereof with various plasticizers, biodegradation accelerators, etc. ,
Nothing is said about the portability of the seat,
Therefore, biodegradable sheets and films formed by melt extrusion using a cellulose acetate resin have not yet been realized. On the other hand, in order to solve the drawback that a plasticizer must be used in the molding and processing of cellulose acetate, and to carry out melt extrusion with high productivity, cellulose acetate is esterified with two kinds of anhydrous fatty acids to obtain cellulose acetate propionate or Attempts have been made in the past to use cellulose acetate butyrate to lower the melting point, but in this case, a new drawback arises in that the hydrophobicity of the film or sheet is increased, and the biodegradability is reduced or disappears.

[0008]

In view of the present situation, the present inventor has previously disclosed in Japanese Patent Application No. 8-254532, a film can be formed by melt extrusion, and there is no transfer of a plasticizer.
A biodegradable cellulose acetate resin composition that does not block even when wound because of low volatile components has been proposed. However, since the main purpose is moisture permeability, the molecular weight of the plasticizer is relatively low, and if the processing conditions are strict with respect to the molding temperature, speed, etc., the volatile components increase, and the plasticizer is directly and via the cooling roll onto the film surface. In some cases, unwinding, fogging the surface, or leaving it unattended for a long period of time may make the unwinding heavy, and therefore, there is a need for improvement in terms of production.

That is, the blocking may occur when the plasticizer migrates from the film or sheet, or may occur when the plasticizer existing on the surface of the film or sheet is superimposed on the film or sheet. It was also found that the fogging of the sheet surface was caused by the migration of the plasticizer from the sheet and the case where the plasticizer was simply present on the film or sheet surface. Therefore, in order to eliminate blocking and fogging, it was found that it is necessary to further lower the volatility of the plasticizer in addition to the fact that the compatibility of the plasticizer does not transfer well to cellulose acetate.

[0010]

In order to improve the productivity of forming a film or a sheet by melt extrusion, the inventors of the present invention have proposed plasticizers from the viewpoint of improving compatibility and suppressing volatility as low as possible. The chemical structure and molecular weight of the agent were studied in detail. As a result, to the extent that blocking and haze are not a problem in terms of migration,
It has been found that the following types of biodegradable plasticizers consisting of aliphatic polyesters and / or derivatives thereof are effective.

An aliphatic polyester having an average molecular weight in the range of 800 to 5000, comprising polyethylene adipate diol;
A biodegradable plasticizer comprising at least one selected from polyethylene succinate diols, mixtures thereof, and copolymers thereof. Same average molecular weight 800-500
0, an aliphatic polyester selected from polycaprolactone diol, polyethylene adipate diol, polyethylene succinate diol, a mixture thereof and a copolymer thereof, and an aliphatic diisocyanate and / or an aliphatic diepoxide. Biodegradable plasticizer consisting of one with chain extension.

An aliphatic polyester amide having an average molecular weight in the range of 800 to 5,000, having at least one selected from the group consisting of polycaprolactone, polyethylene adipate, polyethylene succinate, a mixture thereof, and a copolymer thereof; A biodegradable plasticizer comprising a polyesteramide having at least one selected from aliphatic aminocarboxylic acids, combinations of aliphatic diamines and aliphatic dicarboxylic acids, polycaprolactams, mixtures thereof, and copolymers thereof.

In order to prevent blocking and fogging from becoming a problem from the viewpoint of volatility, a high vapor pressure and a high molecular weight of 300 to 200 ° C. to 250 ° C. are required.
It has been found that it is necessary to reduce the content of the following components, especially those having a molecular weight of 200 or less, as much as possible, specifically as less than 5% by weight, preferably less than 1% by weight.

A first aspect of the present invention is that cellulose acetate having an acetylation degree of 56% or less is 60 to 80% by weight based on the total weight, and 5% by weight of a plasticizer having an average molecular weight of 800 to 5000 and a molecular weight of 300 or less is used. Biodegradable formed by melt-extruding a cellulose acetate-based biodegradable composition containing at least one selected from the group consisting of at least one selected from the group consisting of a biodegradable aliphatic polyester and / or a derivative thereof in an amount of 20 to 40% by weight. The present invention relates to a cellulose acetate-based film and sheet.

The second aspect of the present invention is the above-mentioned average molecular weight of 800.
The biodegradable aliphatic polyester and / or a derivative thereof having a molecular weight of 300 to 5,000 and a component having a molecular weight of 300 or less is selected from polyethylene adipate diol, polyethylene succinate diol, a mixture thereof, and a copolymer thereof. The present invention relates to the cellulose acetate-based biodegradable film and sheet according to the first aspect of the present invention, which comprises at least one kind.

A third aspect of the present invention is the above-mentioned average molecular weight of 800.
A biodegradable aliphatic polyester having a molecular weight of 300 to 5,000 and a component having a molecular weight of 300 or less is less than 5% by weight is preferably polycaprolactone diol, polyethylene adipate diol, polyethylene succinate diol, a mixture thereof, or a mixture thereof. The present invention relates to the cellulose acetate-based biodegradable film and sheet according to the first aspect of the present invention, wherein a polyester component selected from the group consisting of a copolymer is chain-extended with an aliphatic diisocyanate or an aliphatic diepoxide.

The fourth aspect of the present invention is the above-mentioned average molecular weight of 800.
A biodegradable aliphatic polyester and / or a derivative thereof having a molecular weight of 300 or less and a component having a molecular weight of 300 or less is less than 5% by weight, as a polyester component, polycaprolactone, polyethylene adipate, polyethylene succinate, a mixture thereof, and a mixture thereof; At least one selected from aliphatic aminocarboxylic acids, combinations of aliphatic diamines and aliphatic dicarboxylic acids, polycaprolactams, mixtures thereof, and copolymers thereof as polyamide components. And a cellulose acetate-based biodegradable film and sheet according to the first aspect of the present invention.

In the fifth aspect of the present invention, an aliphatic polyester having an average molecular weight of more than 5000 and / or a derivative thereof is added to the biodegradable composition containing cellulose acetate and a plasticizer as main components. The present invention relates to the cellulose acetate-based biodegradable films and sheets according to the first to fourth aspects of the present invention, which are blended in an amount of 5 to 30% by weight based on the total weight of the agent.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The cellulose acetate used in the cellulose acetate-based biodegradable composition of the present invention comprises:
A known method of pretreating cellulose pulp or linter such as softwood bleached kraft pulp or dissolved pulp with acetic acid, then acetylating with acetic anhydride in the presence of an acidic catalyst such as sulfuric acid, and then neutralizing and maturing. And those whose intrinsic biodegradability with an acetylation degree of 56% or less has been confirmed are used. When the acetylation degree of cellulose acetate is less than 51%, the compound is easily degradable and biodegradation is further facilitated. However, a biodegradable compound such as a biodegradable aliphatic polyester or aliphatic polyesteramide is used as a plasticizer. As long as is used, biodegradation can be easily obtained even with cellulose acetate having a degree of acetylation of 51 to 56%. On the other hand, if the acetylation degree is less than 30%, the compatibility with the plasticizer is lowered, and the water resistance of the film or sheet is lowered. Therefore, in the present invention, the degree of acetylation is 30.
It is used in the range of ~ 56%. In addition, two different acetylation degrees
More than one kind of cellulose acetate may be mixed and used. The measurement of the degree of acetylation is carried out according to a known neutralization titration method.
It is determined from the amount of H. As for the average degree of polymerization of cellulose acetate, if it is in the range of 70 to 250 which is usually used, the biodegradability is not significantly affected.

Regarding the blending amount of cellulose acetate, the total weight of cellulose acetate and plasticizer is 60%.
If it is less than 60% by weight, the strength of the film or sheet is reduced. If it exceeds 80% by weight, the melt extrusion temperature is too high, and the thermal stability of the cellulose acetate and the plasticizer is reduced. Not preferred.

The plasticizer used in the cellulose acetate-based biodegradable composition of the present invention includes an average molecular weight of 800
At least one kind of biodegradable aliphatic polyester and / or a derivative thereof containing less than 5% by weight, preferably less than 1% by weight, of a component having a molecular weight of 300 or less in a range of from 5000 to 5000 is exemplified. The reason why the component having a molecular weight of 300 or less is less than 5% by weight is that the component having a molecular weight of 300 or less, particularly 200 or less, has a high vapor pressure near the molding processing temperature and ignores the amount transferred to the film surface directly and via a cooling roll. Because you can't. When the content exceeds 5% by weight, the amount of volatilization increases, and the amount transferred to the film surface becomes a problem depending on molding processing conditions.

As a method of reducing the amount of the component having a molecular weight of 300 or less to less than 5% by weight, when the average molecular weight is 800 or more, in addition to controlling the charging ratio of the diol component and the dibasic acid under the experimental conditions, controlling the reaction conditions, and heating and reducing the pressure. Although fractional distillation below can sufficiently cope with the problem, in some cases, fractionation by preparative chromatography or the like can also be performed. On the other hand, when the average molecular weight is 8
When the molecular weight is less than 00, especially 700 or less, the molecular weight becomes 30.
It is difficult to make the components of 0 or less less than 5% by weight. The quantification of the component having a molecular weight of 300 or less can be confirmed by gel permeation chromatography or quantitative analysis using a mass spectrometer.

The terminal of the aliphatic polyester and / or the derivative thereof must be a hydroxyl group or an amino group which has no reactivity with respect to the hydroxyl group of cellulose acetate. It is desirable that the content be 20% or less of the terminal groups. The ratio of the carboxyl group is calculated as a portion corresponding to the acid value in the sum of the acid value and the hydroxyl value. The acid value is the mg number of calcium hydroxide required to neutralize the carboxyl group in 1 g of the sample, and the hydroxyl value is the water required to saponify the acetylated product obtained from 1 g of the sample. It is determined according to a known method as the number of mg of potassium oxide. Further, the average molecular weight of the plasticizer can be determined according to a known method using the acid value and the hydroxyl value.

The biodegradable aliphatic polyester having an average molecular weight of 800 to 5,000 is preferably polyethylene adipate diol, polyethylene succinate diol, or a mixture or copolymer thereof, from the viewpoint of compatibility. In addition, a biodegradable aliphatic polyester having an average molecular weight of 800 to 5,000 having polycaprolactone diol, polyethylene adipate diol, polyethylene succinate diol or a mixture thereof as a main component, and having a chain extended using an aliphatic diisocyanate or an aliphatic diepoxide. Is also preferable from the viewpoint of compatibility. In addition, those having a molecular weight of 300 or less are easily removed by chain extension. The compounding molar ratio of the chain extender is preferably 0.2 or less per repeating unit 1 of the polyester component.

The biodegradable polyester amide having an average molecular weight of 800 to 5,000 has polycaprolactone, polyethylene adipate, polyethylene succinate or a mixture or copolymer thereof as a polyester component, and an aliphatic aminocarboxylic acid as an amide component.
Those having a combination of an aliphatic diamine and an aliphatic dibasic acid, polycaprolactam, or a mixture or copolymer thereof are desirable from the viewpoint of compatibility. As for the molar ratio of the polyamide component, the repeating unit of the polyamide is preferably 0.3 or less per 1 repeating unit of the polyester component.

As for the average molecular weight of the plasticizer, if the average molecular weight is less than 800, it is not easy to make the component having a molecular weight of 300 or less less than 5% by weight as described above.
It is not preferable that the content be less than 1% by weight, which is a particularly preferable range, since it becomes extremely difficult. On the other hand, if the average molecular weight exceeds 5,000, the plasticizing performance is inferior, the kneading property is reduced, and the molding temperature is undesirably increased. The amount of the plasticizer is 20 to 40% of the total weight of the composition.
% By weight. If the amount is less than 20% by weight, sufficient thermoplasticity cannot be imparted to the cellulose acetate, so that the molding temperature becomes high. If the amount exceeds 40% by weight, problems such as migration of the plasticizer and reduction in strength occur. It is not preferable because it comes.

According to the present invention, a highly soluble aliphatic polyester and / or a derivative thereof can be made compatible with a composition system comprising a cellulose acetate and a plasticizer, which is known to be essentially biodegradable. It is possible to mix the polymer for the purpose of improving the physical properties. In this case, as the high polymer of the aliphatic polyester and / or a derivative thereof, for the aliphatic polyester, polycaprolactone, polyethylene adipate, polyethylene succinate, or the like, a mixture thereof, or a copolymer thereof,
Similarly, in the aliphatic polyester, the polyester component is mainly composed of polycaprolactone diol, polyethylene adipate diol, polyethylene succinate diol or the like, or a mixture or copolymer thereof, and is chain-extended with an aliphatic diisocyanate or an aliphatic diepoxide. No.

The aliphatic polyester amide has polycaprolactone, polyethylene adipate, polyethylene succinate or a mixture or copolymer thereof as a polyester component, and an aliphatic aminocarboxylic acid, an aliphatic diamine and an aliphatic dicarboxylic acid as a polyamide component. And those having a polycaprolactam, a mixture thereof, or a copolymer thereof. The compounding amount is preferably in the range of 5 to 30% by weight based on the total weight of the cellulose acetate and the plasticizer in order to impart necessary physical properties.

In the present invention, a weak organic acid, a phenol compound, an epoxy compound, a phosphate, a thiophosphate is used as a stabilizer for preventing thermal deterioration and preventing thermal coloring within a range not deteriorating the performance required as required. May be added alone or as a mixture of two or more. In addition, it is inevitable to add other additives such as organic acid-based biodegradation accelerators, lubricants, antistatic agents, and lubricants.

The biodegradability is either buried in soil or
In accordance with IS-K-6950, it is possible to evaluate from weight loss and the like. However, since this test is an easy-degradability test method, when examining essential biodegradability, ASTM
It is also possible to use a controlled environment such as soil or activated sludge containing microorganisms adapted to D-5338 or a compound used as cellulose acetate and a plasticizer.

In mixing the cellulose acetate, the plasticizer, the biodegradable polymer and the additives used in the present invention, any conventional materials such as a kneader, an extruder, a roll mill, and a Banbury mixer are used without any particular limitation. In order to facilitate the mixing, it is preferable to previously pulverize the cellulose acetate particles to a size smaller than 50 mesh using a pulverizer. In order to minimize mixing of air bubbles and the like, the kneaded material is desirably formed into a strand using an extruder or the like, and then formed into pellets using a pelletizer. In addition, the biodegradable cellulose acetate composition formed into pellets has a water content of 0.1 in order to prevent hydrolysis and air bubbles during melting prior to the formation of films and sheets by melt extrusion.
It is preferable to dry to 1% or less.

In the production of a film by the melt extrusion method in the present invention, the above-mentioned resin kneading composition is heated and melted in a known extruder, and then extruded from a T-die or a ring die at 200 to 250 ° C. This is a method in which a film is formed by drawing by a take-off device, air pressure, or the like. Here, the temperature at the time of melt extrusion refers to the temperature inside the die. With respect to the melt extrusion temperature, if it exceeds 250 ° C., the thermal stability of the cellulose acetate and the plasticizer decreases, and thermal decomposition and hydrolysis become remarkable, which is not preferable.
On the other hand, when the temperature is lowered to less than 200 ° C., the plasticity of the aliphatic polyester and the aliphatic polyesteramide is lower than that of the phthalic acid ester, so that the melt viscosity of the composition is high and the moldability is reduced.

The melt extrusion method is currently used for various purposes by using resins such as polyethylene, polypropylene, polyethylene terephthalate and the like, and is a method having higher productivity than the casting method requiring a solvent. The biodegradable film and sheet of the present invention are produced by melt-extrusion of a biodegradable resin composition containing cellulose acetate and a plasticizer as main components, and have a thickness of about 10 to 500 μm. In the present invention, a cellulose acetate-based film or sheet having biodegradability can be obtained by a method with extremely high productivity, and can be used alone or in combination with paper, other biodegradable films, sheets, and the like. Thus, it can be applied to the field of packaging of functional wrapping materials and the like in which olefin-based films and sheets have conventionally been used, the field of agricultural materials such as mulch, and the field of construction materials such as anti-condensation films.

[0034]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to these Examples. Example 1 13% by weight of dissolved pulp from softwood, 2% by weight of sulfuric acid, 35% by weight of acetic anhydride and 50% of glacial acetic acid based on the total weight of bone dry
The mixture consisting of wt.% Was acetylated at 36 ° C. for 3 hours. After the reaction, the reaction product was neutralized with potassium acetate, then hydrolyzed at 60 ° C. for 3 hours, purified and dried to obtain a acetylation degree of 54%.
%, An average degree of polymerization of 180 was obtained.

Next, the cellulose acetate flakes were pulverized with a pulverizer, and the cellulose acetate flakes were removed.
%, A component having an average molecular weight of 1200 as a plasticizer and a molecular weight of 300 or less is 3% by weight, and an acid value of 5 (KOHmg /
g) and 30% by weight of polyethylene adipate diol were mixed with a Henschel mixer and kneaded at 200 ° C. using a twin-screw extruder. The kneaded melt is
The mixture was discharged as a strand through a strand die having an inner diameter of 3 mm, and after cooling, cut into 3 mm to obtain a pellet. The pellets are placed in a hot air drier heated to 80 ° C. for 1 hour.
After drying for 0 hour, the mixture was fed to an extruder-type melt extruder to which a T-die was connected.
Then, discharge through a T-die with a lip width of 0.50 mm,
Take-off speed of the discharged melt is 30m /
min. The thickness of the film is 0.03
5 mm. The blocking, surface fogging, strength and biodegradability of the obtained film were evaluated by the following methods.

Evaluation method (1) Blocking: A film of 100 mm / cm ² was subjected to a load of 100 g / cm ^{2 on} a film cut into a width of 25 mm and laminated.
After standing in a blow dryer at 24 ° C. for 24 hours, the adhesive strength was measured at an angle of 180 °. (2) Haze on the surface: The haze of the film was measured according to JIS-K-
Measurement and visual evaluation were performed according to 7105,
The evaluation was performed in three stages (○: no morphological change was observed, Δ:
A morphological change is observed, x: remarkable morphological change). (3) Strength: The breaking strength was measured according to JIS-K-7127. (4) Biodegradability: The melt-extruded film has a length and width of 1
After you have cut to 0cm width, the soil of the field in the Koto-ku, Tokyo (Koto-ku, Tokyo, Shinonome 1-chome 10th No. 6, Oji Paper Co., Ltd.
It was buried at a depth of 25 cm, taken out after 6 months, and evaluated in three stages based on morphological changes and weight changes (○: Both morphological changes and weight loss, Δ: morphological changes, weight changes) Is observed, x: no morphological change or weight change is observed).

Example 2 As in Example 1, 75% by weight of cellulose acetate was used.
2% by weight of a component having an average molecular weight of 1600 and a molecular weight of 300 or less as a plasticizer, and a polyethylene extender having hexamethylene diisocyanate as a chain extender in an amount of 0.2 per repeating unit of polyethylene succinate and an acid value of 3 (KOH mg / g). Using 25% by weight of the nate diol, 2
A film was prepared and tested in the same manner as in Example 1 except that the film was extruded at 40 ° C.

Example 3 70% by weight of cellulose acetate having a degree of acetylation of 45% produced in the same manner as in Example 1 and an average molecular weight of 1 as a plasticizer
500, a component having a molecular weight of 300 or less is 2% by weight, polycaprolactam as a polyamide component is 0.3 with respect to the repeating unit 1 of polycaprolactone, and an acid value is 1 (KOHmg
/ G)) and a film was prepared and tested in the same manner as in Example 1 except that the mixture was melt-extruded at 230 ° C. using 30% by weight of polycaprolactone caprolactam.

Example 4 65% by weight of the same cellulose acetate as in Example 1
2% by weight of a component having an average molecular weight of 1500 and a molecular weight of 300 or less as a plasticizer, 25% by weight of polyethylene succinate diol having an acid value of 3 (KOH mg / g), and an average molecular weight of 20
A film was prepared and tested in the same manner as in Example 1 except that the mixture was melt-extruded at 225 ° C. using 10% by weight of polyethylene succinate of 000.

Comparative Example 1 70% by weight of the same cellulose acetate as in Example 1,
Using 35% by weight of a component having an average molecular weight of 650 and a molecular weight of 300 or less as a plasticizer and 30% by weight of polyethylene adipate diol having an acid value of 8 (KOH mg / g),
A film was produced and tested in the same manner as in Example 1 except that the composition was melt-extruded at a temperature of ℃.

Comparative Example 2 70% by weight of the same cellulose acetate as in Example 1
Using triacetin 30% by weight as a plasticizer, 225
A film was produced and tested in the same manner as in Example 1 except that the composition was melt-extruded at a temperature of ℃.

Comparative Example 3 70% by weight of the same cellulose acetate as in Example 1,
Using a plasticizer containing 18% of a component having an average molecular weight of 870 and a molecular weight of 300 or less and 18% of an acid value of 3 (KOH mg / g) and 30% by weight of polyethylene adipate diol, and extruding the melt at 230 ° C in the same manner as in Example 1 Films were manufactured and tested. Table 1 shows the acetylation degree, blending amount, type of plasticizer, average molecular weight, amount of components having a molecular weight of 300 or less, acid value, and blending amount of the cellulose acetate used in Examples and Comparative Examples. Table 2 shows the measurement results of the physical properties of the obtained film.
It was shown to.

[0043]

[Table 1]

[0044]

[Table 2]

As can be seen from Tables 1 and 2, according to the present invention, a film free from bogging and fogging and a sheet can be produced efficiently by a melt extrusion method, and the obtained film is free from bogging and fogging. It is excellent in biodegradability (Examples 1 to 4). On the other hand, the films of Comparative Examples 1 to 3 containing a conventionally used plasticizer have problems of blocking and fogging.

[0046]

As described in detail above, the present invention provides a cellulose acetate-based biodegradable film and sheet using a cellulose acetate-based resin having excellent biodegradability and moldability by melt extrusion. To play.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mikiko Ishizaki 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Shinonome Research Center (72) Inventor Ryuji Tsuno 5-5 Okubo Tsukuba-shi, Ibaraki Arakawa Chemical (72) Inventor Yusuke Sugihara 5th Okubo, Tsukuba, Ibaraki Pref. Arakawa Chemical Industry Co., Ltd.

Claims (5)

[Claims] 1. A biodegradable aliphatic polyester having 60 to 80% by weight of cellulose acetate having an acetylation degree of 56% or less, and having an average molecular weight of 800 to 5000 and a component having a molecular weight of 300 or less being less than 5% by weight. And / or 20 to 40% by weight of at least one plasticizer selected from derivatives thereof
A biodegradable cellulose acetate-based film and sheet formed by melt-extruding a biodegradable composition containing: 2. A biodegradable aliphatic polyester and / or a derivative thereof having an average molecular weight in the range of 800 to 5000 and a component having a molecular weight of 300 or less in an amount of less than 5% by weight,
The biodegradable cellulose acetate-based film and sheet according to claim 1, wherein the film and sheet are at least one selected from polyethylene adipate diol, polyethylene succinate diol, a mixture thereof, and a copolymer thereof. 3. The biodegradable aliphatic polyester having an average molecular weight in the range of 800 to 5,000 and having a molecular weight of 300 or less and containing less than 5% by weight is polycaprolactone diol, polyethylene adipate diol, or polyethylene succinate. 2. The raw material according to claim 1, which is at least one member selected from the group consisting of nate diols, mixtures thereof and copolymers thereof, and is chain-extended with an aliphatic diisocyanate and / or an aliphatic diepoxide. Degradable cellulose acetate films and sheets. 4. A biodegradable aliphatic polyester having an average molecular weight in the range of 800 to 5,000 and a molecular weight of 300 or less and containing less than 5% by weight of a polycaprolactone or polyethylene adipate as a polyester component, At least one selected from polyethylene succinates, mixtures thereof and copolymers thereof;
A reaction product of at least one selected from a species and an aliphatic aminocarboxylic acid as a polyamide component, a combination of an aliphatic diamine and an aliphatic dicarboxylic acid, polycaprolactam, a mixture thereof, and a copolymer thereof. The biodegradable cellulose acetate film and sheet according to claim 1. 5. A biodegradable composition containing cellulose acetate and a plasticizer as main components, an aliphatic polyester having an average molecular weight of more than 5,000 and / or a derivative thereof is added to the biodegradable composition in an amount of 5 to 5 wt.
The biodegradable cellulose acetate-based film and sheet according to any one of claims 1 to 4, wherein 30% by weight is blended.