JP2003291293A - Biodegradable laminated film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tackifying film which is a biodegradable film being excellent in transparency and flexibility and movable by a T-die extruder and which is free of bleeding of an additive to the surface of the film and has an adhesion durability. <P>SOLUTION: The biodegradable laminated film is constituted of an intermediate layer constituted of a resin composition containing an aliphatic-aromatic polyester resin (A) of 25-98 wt.%, a takifier (D) of 1-30 wt.% and a plasticizer (E) of 1-30 wt.%, and of opposite outer layers constituted of a resin composition containing the aliphatic-aromatic polyester resin (A) of 30-60 wt.%, an aliphatic polyester resin (B) of 20-50 wt.%, the takifier (D) of 0.5-15 wt.% and the plasticizer (E) of 0.5-15 wt.%. The content ratio of at least one of the takifier (D) and the plasticizer (E) in the resin composition of the intermediate layer is made larger than that in the resin composition of the opposite outer layers, and the intermediate layer and the opposite outer layers are molded by co- extrusion. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition containing an aliphatic-aromatic polyester resin, an aliphatic polyester resin, a tackifier and a plasticizer, or a polycaprolactone resin in the resin composition. The present invention relates to a biodegradable laminated film which is composed of an intermediate layer composed of a blended resin composition and both outer layers, has excellent transparency and flexibility, and has tackiness that can be coextruded by a T-die extruder.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a product that is rapidly decomposed after disposal and does not accumulate in a natural environment, and various biodegradable resins are commercially available.

Aliphatic polyester resins are known as biodegradable resins which can be formed into a film by a T-die extruder. For example, polylactic acid resins are excellent in transparency but poor in flexibility. In addition, an aliphatic polyester resin represented by Bionore (trade name, manufactured by Showa High Polymer Co., Ltd.) has poor transparency and its use is limited depending on the application.

On the other hand, as a biodegradable resin having excellent transparency, an aliphatic-aromatic polyester resin obtained by polymerizing an aliphatic-aromatic polyester with a polyfunctional isocyanate is known. When it is formed into a film by a T-die extruder, it is difficult to produce a stable film because the film is strongly adhered to the cast roll and is not easily peeled off from the roll.

The present inventors have further developed a three-component composition comprising an aliphatic-aromatic polyester resin, an aliphatic polyester resin and a polycaprolactone resin,
The above-mentioned problems have been solved by adding a tackifier and a plasticizer, and a biodegradable tackifier film which has excellent transparency and flexibility and can be formed by a T-die extruder has been previously proposed.

However, in the above biodegradable tackifying film, bleeding on the film surface is conspicuous when the blending amount of the tackifier and the plasticizer is increased, while the tackiness persistence is reduced when the blending amount is decreased. So there was a problem that it was difficult to balance it.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a biodegradable tackifier film having a small amount of bleeding of a tackifier and a plasticizer on the surface of the film, and having long-lasting tackiness. .

[0008]

Means for Solving the Problems As a result of intensive studies for achieving the above object, the present inventors have found that an aliphatic-aromatic polyester resin, an aliphatic polyester resin, a tackifier and a plasticizer are contained. A resin composition, or a layer made of a resin composition obtained by blending a polycaprolactone-based resin in the resin composition, as an intermediate layer, and a layer made of the same resin composition as each of the resin compositions is an outer layer on both sides of the intermediate layer. While laminating as, by making the amount of at least one of the tackifier and the plasticizer blended in the intermediate layer larger than the amount blended in the outer layer, excellent transparency and flexibility,
In addition, they have found that a film in which bleeding of tackifiers and plasticizers can be suppressed and stickiness can be easily controlled can be formed by a T-die extruder, and the present invention has been completed.

That is, the gist of the present invention is that an aliphatic-aromatic polyester resin (A) is a polycondensate of a dicarboxylic acid component composed of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and a diol component composed of an aliphatic diol. ) 25-9
8% by weight, a tackifier (D) 1 to 30% by weight and a plasticizer (E) 1 to 30% by weight of a resin composition, and the aliphatic-aromatic polyester resin (A) 30 to 60% by weight, a polycondensate of a dicarboxylic acid component composed of an aliphatic dicarboxylic acid and a diol component composed of an aliphatic diol, and having a melt flow rate of 1 to 9 g.
/ 10 minutes aliphatic polyester resin (B) 20 to
50% by weight, 0.5 to 15% by weight of a tackifier (D) and 0.5 to 15% by weight of a plasticizer (E) and both outer layers of the resin composition, and the intermediate layer The content ratio of at least one of the tackifier (D) and the plasticizer (E) in the resin composition is higher than the content ratio in the resin composition of both outer layers, and the intermediate layer and both outer layers are It exists in a biodegradable laminated film formed by coextrusion.

The resin composition for the intermediate layer further contains 0 to 50% by weight of the aliphatic polyester resin (B) and 0 to 20% by weight of the polycaprolactone resin,
The resin composition of both outer layers is characterized by further containing 0 to 20% by weight of the polycaprolactone resin (C).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The aliphatic-aromatic polyester resin (A) used in the present invention comprises a dicarboxylic acid component composed of adipic acid and terephthalic acid,
It is preferable to polymerize an aliphatic-aromatic polyester obtained by condensing a diol component composed of 1,4-butanediol with a polyfunctional isocyanate, and as a component other than the above 1,4-butanediol. , 2,3-
Butanediol, 1,3-butanediol, 1,4-pentanediol, 1,5-pentanedigol, 2,4-
Pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol and the like can be mentioned.

Further, as the aliphatic polyester resin (B) used in the present invention, an aliphatic polyester obtained by condensing a dicarboxylic acid component composed of succinic acid and a diol component composed of butanediol is highly functionalized with a polyfunctional isocyanate. It is preferably a molecularized aliphatic polyester. Other dicarboxylic acid components include aliphatic dicarboxylic acids such as adipic acid, sebacic acid, and itaconic acid, with succinic acid being preferred. Other diol components include 2,3-butanediol,
1,3-butanediol, 1,4-pentanediol,
1,5-pentanediol, 2,4-pentanediol,
1,6-hexanediol, neopentyl glycol,
Aliphatic diols such as ethylene bricol and diethylene glycol can be mentioned, but 1,4-butanediol is preferable. The melt flow rate (MFR) of the aliphatic polyester resin (B) is 1 to 9 g /
10 minutes (190 ° C., 2.16 kg-load), preferably 2 to 8 g / 10 minutes, particularly preferably 4 to 7 g / 1
0 minutes.

MF of the above aliphatic polyester resin (B)
If R is less than 1 g / 10 minutes, the moldability of the film deteriorates, and if it exceeds 9 g / 10 minutes, a surging phenomenon occurs.
It makes continuous production of the film difficult.

The polycaprolactone resin (C) used in the present invention is not limited to a homopolymer of caprolactone, but may be a copolymer of caprolactone and another aliphatic hydroxycarboxylic acid. The number average molecular weight Mn of the polycaprolactone resin (C) is 30,000.
0 to 300,000, preferably 40,000 to 20
It is 10,000.

Examples of the tackifier (D) used in the present invention include natural resin-based rosin ester-based and terpene resin-based ones, aromatic hydrocarbon resins, and aliphatic hydrocarbon resins. .

The plasticizer (E) used in the present invention is a plasticizer of an aliphatic-aromatic polyester resin (A), an aliphatic polyester resin (B), and a polycaprolactone resin (C). As long as it can be used as, is not particularly limited, for example, triethylene glycol, aliphatic alcohol plasticizer such as polyethylene glycol, tributyl acetyl citrate, glycerin monolauryl diacetate, Triacetin, aliphatic ester plasticizers such as sebacic acid, epoxidized soybean oil as a modified product of ester, epoxidized linseed oil, and the like, preferably,
An acetylated monoglyceride type plasticizer is mentioned.

The content ratio of each component in the resin composition constituting the intermediate layer of the biodegradable laminated film of the present invention is 25 to 98% by weight of the aliphatic-aromatic polyester resin (A) and the aliphatic polyester resin. Resin fat (B) 0 to 50% by weight, polycaprolactone resin (C) 0 to 20% by weight, tackifier (D) 1 to 30% by weight, plasticizer (E)
Is 1 to 30% by weight.

Regarding the content ratio of each of the above components, when the aliphatic-aromatic polyester resin (A) is less than 25% by weight, a laminated film having good flexibility and transparency cannot be obtained, and the aliphatic polyester 50% by weight of resin (B)
When the content exceeds the above range, the flexibility of the laminated film is lowered, and when the polycaprolactone resin (C) is contained in an amount of 3% by weight or more, the effect of improving the transparency and flexibility of the film is recognized. If it exceeds, the transparency of the film will rather decrease.

When the content ratio of the tackifier (D) and the plasticizer (E) in the intermediate layer exceeds 30% by weight, it becomes difficult to suppress the bleeding of each contained component on the film surface. Further, at least one content ratio, preferably by making both content ratios larger than the content ratio in the surface layer, the bleeding to the film surface of the both content components is appropriately controlled,
Sufficient stickiness can be obtained.

The content ratio of each component in the resin composition constituting both outer layers of the biodegradable laminated film of the present invention is 30 to 60% by weight of the aliphatic-aromatic polyester resin (A) and the aliphatic polyester resin. Resin (B) 20 to 50% by weight, polycaprolactone resin (C) 0 to 20% by weight, tackifier (D) 0.5 to 15% by weight, plasticizer (E) 0.5 to 15% % By weight.

Aliphatic-Aromatic Polyester Resin (A)
When it is less than 30% by weight, a laminated film having good flexibility and transparency cannot be obtained, and when it exceeds 60% by weight, the extruded film has a strong tendency to adhere to a cast roll, resulting in productivity of the laminated film. Becomes worse. When the amount of the aliphatic polyester resin (B) exceeds 50% by weight, the transparency and flexibility of the laminated film deteriorate. When the polycaprolactone resin (C) exceeds 20% by weight, the extruded film tends to stick to the cast roll, which is not preferable.

When the blending ratio of the tackifier (D) is less than 0.5% by weight, the self-adhesiveness of the film is insufficient, and 1
If it exceeds 5% by weight, bleeding on the film surface tends to be conspicuous.

The compounding ratio of the plasticizer (E) is 0.5% by weight.
If it is less than 15%, the effect of improving the transparency of the film is not sufficient, and if it exceeds 15% by weight, bleeding on the film surface tends to be conspicuous.

The resin composition constituting each layer of the biodegradable laminated film of the present invention may optionally contain additives within a range not impairing the effects of the present invention. As the additives to be blended, all known resin additives can be mentioned. Examples thereof include heat stabilizers, lubricants, antiblocking agents, nucleating agents, antioxidants, ultraviolet stabilizers, antibacterial agents, fillers, coloring agents, antistatic agents, and starch.

Although the thickness of the biodegradable laminated film of the present invention varies depending on the use, it is usually about 10 to 100 μm, and the ratio of the thickness of the intermediate layer to the thickness of both outer layers is not particularly limited. 10-5 depending on the thickness
In the case of a relatively thin film having a thickness of about 0 μm, it is preferable that the thickness of the intermediate layer is about 1/8/1 to 3/4/3.

As a kneading method of the resin composition constituting each layer of the biodegradable laminated film of the present invention, a general method can be preferably used. Specifically, pellets, powders, solid particles, etc. are dry-mixed with a Henschel mixer or a ribbon mixer, and then mixed with a known melt-kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll. It can be supplied and melt-kneaded. For example, in the case of a resin composition comprising an aliphatic-aromatic polyester resin, an aliphatic polyester resin and polycaprolactone,
First, each resin is put in a tumbler and mixed by stirring for 10 to 20 minutes. Then, using a single-screw or twin-screw extruder,
The resin composition can be pelletized by melt-kneading at a temperature of 0 to 210 ° C.

In the present invention, the method of molding the laminated film from the resin composition constituting each layer is a coextrusion molding in which the film laminated by the multilayer T die using a plurality of extruders is cooled and solidified by a cast roll. Are suitable.

The biodegradable laminated film of the present invention can be used for silage films, industrial or household wrap films, pallet stretch films and the like. Further, depending on the purpose of use, the biodegradable laminated film of the present invention can be used in combination with another biodegradable film.

[0029]

EXAMPLES Examples of the present invention will be given below, but the present invention is not limited to these examples. The laminated film obtained in the present invention was evaluated by the following evaluation items.

(Self-adhesiveness) Film samples cut into a size of 100 mm in width and 200 mm in length were placed in a thermostatic chamber set at a temperature of 23 ° C., and the following criteria were evaluated. ◯: The films stick to each other, and when the upper film is lifted, the lower film sticks to the upper film and is lifted. X: The films do not stick to each other, and the lower film does not lift even if the upper film is lifted.

(Adhesion Persistence) The self-adhesiveness of a film sample left for a certain period of time in a thermostatic chamber set at a temperature of 23 ° C. was evaluated and evaluated according to the following criteria. ◯: Self-adhesiveness is maintained for 6 months or more. Δ: Self-adhesiveness is maintained for 3 months or more and less than 6 months. X: Self-adhesiveness disappears in less than 3 months.

(Roll Removability) The degree by which the laminated film coextruded from the T die was smoothly peeled from the cast roll (removability) was evaluated according to the following criteria. ○: The film peels off smoothly from the roll ×: The film does not peel off smoothly from the roll and sticks to the roll

(Transparency) The total light transmittance of the film sample was measured with a spectrophotometer (V-570 manufactured by JASCO Corporation),
The transparency was evaluated according to the following criteria. ⊚: Total light transmittance of 70% or more ○: Total light transmittance of 65% or more and less than 70% Δ: Total light transmittance of 60% or more, less than 65% ×: Total light transmittance of less than 60%

(Bleed property) After leaving the film sample for 30 minutes in an oven set to a temperature of 50 ° C., the surface condition of the sample was visually observed and evaluated according to the following criteria. B: No bleeding is observed. X: Bleed is considerably observed.

Compounding ingredients such as biodegradable resins used in Examples and Comparative Examples of the present invention are shown below. Aliphatic-aromatic polyester resin (A): "Ecoflex" manufactured by BSF (polymerization of polycondensate of adipic acid, terephthalic acid and 1,4-butanediol with polyfunctional isocyanate, MFR 5.0
g / 10 minutes) Aliphatic polyester resin (B): "Bionole # 1903" manufactured by Showa Highpolymer Co., Ltd. (a polycondensation product of succinic acid and 1,4-butanediol polymerized with a polyfunctional isocyanate) , MFR: 5.5 g / 10 min), "Bionole # 1001" (polymerization of polycondensate of succinic acid and 1,4-butanediol with polyfunctional isocyanate, MFR: 2.0 g / 10 min) ) Polycaprolactone-based resin (C): "Plaxel H7" (number average molecular weight 70,000) manufactured by Daicel Chemical Industries, Ltd. Tackifier (D): "Ester gum RE" (rosin ester-based) manufactured by Arakawa Chemical Industries, Ltd. Plasticizer (E): "Rikemar PL-" manufactured by Riken Vitamin Co., Ltd.
009 "(glycerin monolauryl diacetate)

Examples 1 to 6 and Comparative Examples 1 to 6 The resin compositions and additives shown in Table 1 were mixed in the compounding ratio shown in Table 1 to prepare resin compositions for the outer layer and the intermediate layer. . Then, each resin composition was supplied to different extruders, and the film coextruded from the multilayer die was heated to 30 ° C.
The film was cooled with a cast roll set to a temperature of 2 to obtain a laminated film having a thickness of 25 μm and a thickness ratio of outer layer / middle layer / outer layer of 2/6/2. The peeling property from the cast roll of the coextruded film was observed, and the self-adhesiveness, stickiness persistence, transparency and bleeding property of the obtained laminated film were evaluated. The evaluation results are shown in Table 1.

[0037]

[Table 1]

[0038]

As is apparent from the above examples, according to the present invention, a laminated film having a three-layer structure in which an outer layer and an intermediate layer are laminated, and the content of the tackifier and / or the plasticizer in the intermediate layer is Is larger than the content in the outer layer, the bleeding amount of the tackifier and the plasticizer on the film surface is small, and the adhesive has long-lasting adhesiveness, excellent transparency and flexibility, and is produced by the T-die extruder. It is possible to obtain a biodegradable tackifying film capable of

Continued front page    F term (reference) 4F100 AK41A AK41B AK41C AL05A                       AL05B AL05C BA03 BA06                       BA10A BA10C BA27A BA27B                       BA27C CA04A CA04B CA04C                       CA16A CA16B CA16C EH202                       GB15 GB23 JA06A JA06C                       JA07A JA07B JA07C JC00                       JK13 JN01 YY00A YY00B                       YY00C

Claims (7)

[Claims] 1. An aliphatic-aromatic polyester resin (A), which is a polycondensate of a dicarboxylic acid component composed of an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid and a diol component composed of an aliphatic diol, in an amount of 25 to 98% by weight. , Tackifier (D)
1 to 30% by weight and a plasticizer (E) 1 to 30% by weight of a resin composition, the aliphatic-aromatic polyester resin (A) 30 to 60% by weight, aliphatic dicarboxylic acid 20 to 50% by weight of an aliphatic polyester resin (B), which is a polycondensate of a dicarboxylic acid component consisting of ## STR1 ## and a diol component consisting of an aliphatic diol, and has a melt flow rate of 1 to 9 g / 10 minutes, a tackifier (D)
And the outer layer comprising a resin composition containing 0.5 to 15% by weight and a plasticizer (E) of 0.5 to 15% by weight. A biodegradable laminate obtained by increasing the content ratio of at least one of D) and the plasticizer (E) to a content ratio in the resin composition of both outer layers and coextruding the intermediate layer and both outer layers. the film. 2. The resin composition for the intermediate layer further contains 0 to 50% by weight of the aliphatic polyester resin (B) and 0 to 20% by weight of the polycaprolactone resin (C). Biodegradable laminated film. 3. The biodegradable laminated film according to claim 1, wherein the resin composition for both outer layers further contains 0 to 20% by weight of a polycaprolactone resin (C). 4. A polycaprolactone resin (C) in the resin composition of at least one of the intermediate layer and the outer layers.
The biodegradable laminated film according to claim 2 or 3, wherein the content ratio of is 3 to 20% by weight. 5. The aliphatic dicarboxylic acid of the aliphatic-aromatic polyester resin (A) is adipic acid, the aromatic carboxylic acid is terephthalic acid, and the aromatic diol is 1,4-butanediol. The biodegradable laminated film according to claim 1. 6. The dicarboxylic acid component of the aliphatic polyester resin (B) is succinic acid, and the diol component is 1,
The biodegradable laminated film according to claim 1 or 2, which is 4-butanediol. 7. The biodegradable laminated film according to claim 2, wherein the polycaprolactone resin (C) has a molecular weight of 40,000 to 200,000.