JP4982064B2 - Biodegradable cap - Google Patents

Description

The present invention relates to a synthetic resin cap having biodegradability, and more particularly to a pull-open cap having biodegradability.

Conventionally, caps are manufactured by known molding means such as injection molding and compression molding using synthetic resins such as polypropylene and polyethylene, but in recent years, caps are molded using biodegradable resins that decompose under natural environments. It has been proposed to do. (For example, refer to Patent Document 1) Capability required for the cap includes hermeticity, tamper evidence, unsealing property, etc. As a cap excellent in these performances, a pull having a breakable thin portion Open caps are widely used.

JP 2003-301096 A

The pull open cap here refers to a cap provided with a cut-off area partitioned by a thin-walled portion on the top wall of the cap body so that it can be broken, and has a finger hook in the cut-out area of the top wall. A cap having a column extending upward from a cut region of the top wall and a pull ring connected to the column is exemplified, and the cap is mainly formed using polyethylene resin. In this type of cap, it is a well-known and commonly used technique to set the thickness of the breakable thin portion around 0.25 mm, but the thickness of the breakable thin portion using a biodegradable aliphatic polyester resin is known. Is set near 0.25 mm, there is a problem that it is difficult to open. Further, if the pull ring is pulled strongly at the time of opening, there is a problem that the breakable thin portion is torn off vigorously, and the content liquid adhering to the cut area is scattered and adheres to the user's clothes and the like.

The present invention provides a cap having an openability equal to or higher than that of a conventionally used polyethylene pull-open cap and having excellent biodegradability under composting conditions in a natural environment. Another object of the present invention is to improve the scattering of the content liquid at the time of opening, which has been a problem with conventional biodegradable resin caps.

（Ｒ^３はＨ、Ｃ_１〜_５の脂肪族アシル基またはＣ_６〜_１２の芳香族アシル基を示し、Ｒ^４、Ｒ^５、Ｒ^６は全てが同一ではなく、それぞれ下記一般式（Ｄ’）または一般式（Ｄ’’）で表される）

（Ｒ^７はＣ_１〜_６のアルキレン基を示し、Ｒ^８はＣ_１〜_１０の直鎖もしくは分岐状のアルキル基、Ｃ_６〜_１２のアリール基、Ｃ_７〜_１５のアリールアルキル基またはＣ_７〜_１５のアルキルアリール基を示し、ｐは０〜６の整数を示す）

（Ｒ^９はＣ_１〜_６のアルキレン基を示し、Ｒ^１０はＣ_１〜_１０の直鎖もしくは分岐状のアルキル基、Ｃ_６〜_１２のアリール基、Ｃ_７〜_１５のアリールアルキル基またはＣ_７〜_１５のアルキルアリール基を示し、ｑは０〜６の整数を示す） As a result of intensive studies to solve the above problems, the present inventors have found that the adipate represented by the following general formula (A) or (B) or (C) as a plasticizer for the biodegradable aliphatic polyester resin Or by forming a cap using a composition containing a citrate ester represented by the following general formula (D) in a specific ratio as a raw material, a pull-open cap excellent in openability can be obtained. Invented.

(R ³ represents H, an aliphatic acyl group of C ₁ to ₅ or an aromatic acyl group of C ₆ to ₁₂ , and R ⁴ , R ⁵ and R ⁶ are not all the same, and each of the following general formulas (D ′ ) Or general formula (D ″))

^{(R 7} represents an alkylene group of _C 1 _{~ 6,} ^{R 8} is _C 1 linear or branched alkyl group of _{~ 10,} C ₆ aryl group _{~ 12,} C _{7 ~} arylalkyl group or _{C 7 15} To ₁₅ alkylaryl groups, and p represents an integer of 0 to 6)

(R 9 is an alkylene group of C 1 ~ 6, R 10 is C 1 linear or branched alkyl group of ~ 10, C 6 aryl group ~ 12, C 7 ~ arylalkyl group or C 7 15 To 15 alkylaryl groups, q represents an integer of 0 to 6)

According to the present invention, the cap is made of a biodegradable aliphatic polyester resin, and the cap includes a top wall in which a cut region is defined by a breakable thin portion, and a finger hook portion provided in the cut region. The biodegradable aliphatic polyester resin contains the specific adipic acid ester or citric acid ester in a specific ratio. The blending amount of the adipic acid ester or citric acid ester with respect to the biodegradable aliphatic polyester resin is 2 to 40 parts by weight per 100 parts by weight of the biodegradable aliphatic polyester. In the present invention, the blending amount is preferably in the range of 10 to 25 parts by weight per 100 parts by weight of the biodegradable aliphatic polyester, from the viewpoint of openability.
The biodegradable aliphatic polyester resin used for the cap of the present invention is characterized by being a polyalkylene alkanoate, a copolymer thereof, or a mixture thereof. The biodegradable aliphatic polyester resin used for the cap of the present invention is characterized by being polybutylene succinate or a copolymer thereof, or a mixture thereof. The copolymer of polybutylene succinate used in the cap of the present invention is polybutylene succinate adipate. The biodegradable aliphatic polyester resin used for the cap of the present invention is characterized in that it has a high molecular weight using a chain extender. The copolymer of the biodegradable aliphatic polyester resin used for the cap of the present invention is polybutylene adipate terephthalate. The biodegradable aliphatic polyester resin mixture used for the cap of the present invention is characterized by comprising at least two selected from polybutylene succinate, polybutylene succinate adipate, and polybutylene adipate terephthalate. . The biodegradable aliphatic polyester resin used for the cap of the present invention contains 0.1 to 5 parts by weight of fatty acid, or fatty acid amide, or a mixture of fatty acid and fatty acid amide per 100 parts by weight of biodegradable aliphatic polyester. It is characterized by blending. The biodegradable aliphatic polyester resin used for the cap of the present invention is characterized by blending 1 to 10 parts by weight of an antiblocking agent per 100 parts by weight of the biodegradable aliphatic polyester. The finger hook portion of the cap of the present invention is characterized by comprising a support column extending upward from the cutout region and a pull ring connected to the support column.

According to the present invention, by adding a specific adipic acid ester or citric acid ester to a biodegradable aliphatic polyester resin, good openability is achieved while maintaining sealing performance without impairing biodegradability. Furthermore, it is possible to prevent the liquid contents from being scattered at the time of opening.

The present invention will be described in detail below.
In the present invention, the cap is made of a biodegradable aliphatic polyester resin, and the cap has a top wall in which a cut region is defined by a breakable thin portion, and a finger hook portion provided in the cut region. The cap is characterized in that the biodegradable aliphatic polyester resin contains the specific adipic acid ester or citric acid ester. When the adipic acid ester or citric acid ester is added to the biodegradable aliphatic polyester resin, the blending amount of the adipic acid ester or citric acid ester with respect to the biodegradable aliphatic polyester per 100 parts by weight of the biodegradable aliphatic polyester , The opening property which was excellent in the cap can be provided by setting to 2-40 weight part. When the blending amount of adipic acid ester or citric acid ester with respect to the biodegradable aliphatic polyester is larger than the above range, there is a high possibility that the liquid adipic acid ester or citric acid ester bleeds out during use. Moreover, when the compounding quantity of the adipic acid ester or citrate ester with respect to biodegradable aliphatic polyester is smaller than the said range, the effect as a plasticizer of an adipic acid ester or a citrate ester will become thin, and it will not contribute to the improvement of openability. Preferably, the blending amount of adipic acid ester or citric acid ester with respect to the biodegradable aliphatic polyester is set to 10 to 25 parts by weight per 100 parts by weight of the biodegradable aliphatic polyester. Furthermore, the cap which improved the scattering of the content liquid at the time of opening can be obtained. Adipic acid ester and citric acid ester can be used alone or as a mixture.

The biodegradable aliphatic polyester resin used in the composition of the present invention is obtained by condensing one or more of each of the following aliphatic polyhydric alcohols and aliphatic polybasic acids (or derivatives thereof). Can be used arbitrarily. In the present invention, the “biodegradable aliphatic polyester resin” includes those synthesized from cycloaliphatic compounds.

Examples of the aliphatic polyhydric alcohol that is one of the raw materials of the biodegradable aliphatic polyester resin used in the present invention include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,8- Examples include octylene glycol, 1,10-decamethylene glycol, and 1,4-cyclohexanedimethanol. Among these, ethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol are preferable in view of physical properties of the resulting biodegradable aliphatic polyester resin.

Examples of the aliphatic polybasic acid (or a derivative thereof) that is one of the raw materials of the biodegradable aliphatic polyester resin used in the present invention include succinic acid, succinic anhydride, adipic acid, sebacic acid, and dodecanedicarboxylic acid. Examples include 1,4-cyclohexanedicarboxylic acid. Among these, succinic acid and adipic acid are preferable in view of physical properties of the resulting biodegradable aliphatic polyester resin. Moreover, you may use together aromatic polybasic acids, such as a terephthalic acid, as a copolymerization component.

Biodegradable aliphatic polyester resins suitable for the present invention include polybutylene succinate, which is a dehydration condensate of 1,4-butanediol and succinic acid, 1,4-butanediol and succinic acid, and adipic acid. Examples thereof include polybutylene succinate adipate which is a dehydration condensate. These biodegradable aliphatic polyester resins are preferably those having a high molecular weight using a chain extender such as lactic acid, polyvalent isocyanate, or acid anhydride. Examples thereof include a mixture of polybutylene adipate terephthalate obtained by dehydration condensation of 1,4-butanediol, adipic acid, and terephthalic acid, and the polybutylene succinate and polybutylene succinate adipate. In addition, other biodegradable resins such as polylactic acid and starch can be used by mixing with the biodegradable aliphatic polyester resin exemplified above or a mixture thereof. As a method for mixing the mixture, known mixing means such as dry blending of pellets, melt kneading using an extruder or the like can be used.

As a method for mixing the biodegradable aliphatic polyester resin or a mixture thereof and adipic acid ester or citric acid ester, a known mixing means such as direct blending of resin pellets and a plasticizer, melt kneading using an extruder or the like is used. Can do.

In the cap of the present invention, it is desirable to blend 0.01 to 5 parts by weight of a lubricant per 100 parts by weight of the biodegradable aliphatic polyester for the purpose of improving the releasability at the time of molding the resin. When molding by injection molding using a cold runner, it is necessary to consider not only the mold releasability of the mold part forming the molded product but also the mold releasability from the sprue. For this reason, in the cap of this invention, the mold release property at the time of shaping | molding can be improved and a moldability can be improved by mix | blending the said specific amount of lubricant.

Further, as an advantage of containing a lubricant, it is possible to improve the biting property of the resin into the screw during molding. When a specific amount of lubricant is included when the resin is introduced into the molding machine, the resin flows smoothly through the screw. However, if a lubricant exceeding the specified range is added, the bite property is adversely affected, resulting in molding failure.

As the lubricant, a so-called internal lubricant for imparting internal lubricity and an external lubricant for imparting external lubricity can be used together, and these can be used in combination. As the lubricant used in the present invention, all those generally used for resin molding can be applied. However, particularly when the resin composition of the present invention is used for food packaging, as a food additive. It is desirable to use one that has been approved for use.
Specifically, fatty acids such as stearic acid proposed in JP-A-8-27363, erucic acid amide, methylene bis-stearic amide, ethylene bis-stearic amide, ethylene bis-palmitic acid amide, ethylene bis-oleic acid Fatty acid amides such as amides, or a mixture of the above fatty acids and fatty acid amides can be used.

In addition to the above-mentioned lubricant, it is necessary to improve the moldability by forming irregularities on the surface of the molded product of the cap, increasing the surface roughness, and adjusting the resin biting property to improve the moldability. The antiblocking agent is preferably added in an amount of 1 to 10 parts by weight per 100 parts by weight of the biodegradable aliphatic polyester. A conventionally well-known antiblocking agent can be used as an antiblocking agent, A talc particle can be used suitably.

The above-mentioned lubricant and antiblocking agent may be added by preparing a masterbatch containing these at a relatively high concentration, and may be an internal addition in which this masterbatch is blended, or an external addition in which an antiblocking agent is directly added to the pellet particles. good.

Further, in the present invention, for the purpose of suppressing hydrolysis, it is preferable to add 0.1 to 10 parts by weight of a hydrolysis inhibitor per 100 parts by weight of the biodegradable aliphatic polyester. Since the cap is frequently used for packaging a food seasoning solution containing water, hydrolysis resistance is required. In the present invention, by adding the specific amount of hydrolysis inhibitor, hydrolysis resistance can be improved without impairing the biodegradability inherent in the biodegradable aliphatic polyester resin. The type of the hydrolysis inhibitor is not particularly limited as long as hydrolysis can be suppressed.

Examples of the hydrolysis inhibitor include carbodiimide compounds, surface-treated inorganic fillers, synergistic silicates, hydrophobic waxes, hydrophobic plasticizers, and olefinic resins proposed in Japanese Patent No. 3514736 and Japanese Patent Application Laid-Open No. 2003-165917. At least one of the groups is selected.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

A cap as shown in FIG. 1 was molded with an injection molding machine. Thereafter, the pull-open strength was measured, and the presence or absence of liquid leakage due to the pinhole in the breakable thin portion was examined. Furthermore, the scattering of the content liquid at the time of opening was confirmed by actually pull-opening. In this example, esters represented by the following general formulas (A), (B), and (C) were used as plasticizers.

(cap)
As shown in FIGS. 1 and 2, the pull-open cap A is connected to the top wall 3 in which the cutout region 2 is partitioned by the breakable thin portion 1, the column 5 extending upward from the cutout region 2, and the column 5. The pull ring 4 is provided. The cap A has an engaging projection 8 on the inner surface of the outer cylinder wall 7 that engages with an annular protrusion provided on the outer periphery of the mouth tube portion of the container (not shown), and the mouth tube portion is sealed with a stopper. Installed. In addition, it replaces with the said pull ring 4, A well-known finger hook part can be employ | adopted, such as providing a press protrusion so that a cutting area can be fractured | ruptured by a press. Further, the entire cut region may be cut off, or may be cut off with a part of the unbroken portion remaining. Moreover, the pouring hole formed by breaking the breakable thin wall portion can adopt a known shape as appropriate. However, as shown in FIG. 2a can also be narrowed. The mounting of the cap on the container is not limited to the above-described means, and a known means such as mounting with a screw can be employed.

(Measurement of pull open strength)
Using a tensile tester, the pull open strength was measured by the following procedure. After fixing a measurement sample that has passed 24 hours or more after molding with a jig, pull the pull ring at a speed of 300 mm / min in a direction 90 degrees above the top wall surface, and the initial peak value in the fracture process of the thin-walled portion ( Maximum) was recorded. As for the unsealing properties, those having a pull-open strength of less than 60N are good, those having a pull-open strength of 60N or more and less than 80N are acceptable, and those having a pull-open strength of 80N or more are impossible.

(Confirmation of liquid splash)
The content liquid was confirmed to be scattered when opened. A cap was attached to the container containing the content liquid, and the container was shaken up and down 10 times, and then the pullable ring was pulled to tear the breakable thin-walled portion to remove the cut region. At this time, a liquid with no liquid splash or a liquid with almost no liquid splash was good, a liquid with a slight liquid splash was allowed, and a liquid with a liquid splash was not allowed.

(Leakage test)
Using a desiccator, the presence or absence of liquid leakage due to pinholes in the breakable thin wall portion was confirmed under reduced pressure.
The test procedure is as follows.
A glass container is filled with 50% aqueous ethanol solution in which a methylene blue solution is dissolved, and then a cap is attached to the container. The cap has an engagement projection on the inner surface of the outer cylinder wall that engages with an annular protrusion provided on the outer periphery of the mouth tube portion of the glass container, and the cap is liquid-tight on the container mouth tube portion by a stopper. Installed. The container with the cap is laid down for 20 minutes in a desiccator set to an internal pressure of 200 hPa, and then the presence or absence of liquid leakage is confirmed. Caps that did not leak were good, and caps that leaked were not.

Example 1
Using a resin comprising 100 parts by weight of polybutylene succinate adipate and 25 parts by weight of adipic acid ester (general formula (A)), a cap having a ruptureable thin part having a thickness of 0.25 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 43 N, and the openability was good. Regarding the splattering of the liquid at the time of opening, the liquid hardly splattered and was good.

(Example 2)
Using a resin comprising 100 parts by weight of polybutylene succinate adipate and 25 parts by weight of adipic acid ester (general formula (B)), a cap having a ruptureable thin part having a thickness of 0.25 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 45 N, and the openability was good. Regarding the splattering of the liquid at the time of opening, the liquid hardly splattered and was good.

Example 3
Using a resin comprising 100 parts by weight of polybutylene succinate adipate and 18 parts by weight of adipic acid ester (general formula (A)), a cap having a ruptureable thin part having a thickness of 0.25 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 50 N, and the openability was good. Regarding the splattering of the liquid at the time of opening, the liquid hardly splattered and was good.

Example 4
Using a resin comprising 100 parts by weight of polybutylene succinate adipate and 18 parts by weight of adipic acid ester (general formula (C)), a cap having a ruptureable thin part having a thickness of 0.25 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 52 N, and the openability was good. Regarding the splattering of the liquid at the time of opening, the liquid hardly splattered and was good.

(Example 5)
Using a resin comprising 100 parts by weight of polybutylene succinate adipate and 11 parts by weight of adipic acid ester (general formula (A)), a cap having a ruptureable thin part having a thickness of 0.25 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 58 N, and the openability was good. Regarding the splattering of the liquid at the time of opening, the liquid hardly splattered and was good.

(Example 6)
Using a resin comprising 100 parts by weight of polybutylene succinate adipate and 5 parts by weight of adipic acid ester (general formula (A)), a cap having a ruptureable thin part having a thickness of 0.25 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 76 N, and the openability was acceptable. About the splash of the content liquid at the time of opening, the splash of the liquid was slight and was possible.

(Example 7)
A cap comprising 100 parts by weight of polybutylene succinate adipate and 30 parts by weight of adipic acid ester (general formula (A)) was used, and a cap having a breakable thin part having a thickness of 0.30 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 48 N, and the openability was acceptable. About the splash of the content liquid at the time of opening, the splash of the liquid was slight and was possible.

(Comparative Example 1)
Using a resin composed of 100 parts by weight of polybutylene succinate adipate and containing no plasticizer, a cap having a ruptureable thin part having a thickness of 0.25 mm was injection molded. A leak test was performed in the desiccator, but no liquid leak from the thin breakable part was observed. When the pull-open strength was measured, it was 98 N, and the openability was not possible. The contents of the unsealed contents were not allowed to splatter due to liquid splattering.
The results are shown in Table 1.
(Comparative Example 2)
Using a resin consisting of 100 parts by weight of polybutylene succinate adipate and 50 parts by weight of adipic acid ester (general formula (A)), a cap having a ruptureable thin part thickness of 0.25 mm was injection molded. The experiment was canceled because it was a molded product that was remarkably unsuitable for use.

＊配合量は樹脂１００重量部あたりの量を示す。

* The blending amount indicates the amount per 100 parts by weight of the resin.

As is apparent from the above results, the cap is made of a biodegradable aliphatic polyester resin, and the cap is provided on the top wall in which the cut region is defined by a breakable thin portion and the cut region. In the cap having the finger part, the blending amount of the specific adipic acid ester or citric acid ester with respect to the biodegradable aliphatic polyester is 2 to 40 parts by weight, preferably biodegradable per 100 parts by weight of the biodegradable aliphatic polyester. By using 10 to 25 parts by weight of the resin per 100 parts by weight of the aliphatic aliphatic polyester, good openability can be realized while maintaining the sealing property, and the splashing of the liquid can be improved. By blending 0.1 to 5 parts by weight of a fatty acid, or a fatty acid amide, or a mixture of a fatty acid and a fatty acid amide as a lubricant per 100 parts by weight of the biodegradable aliphatic polyester, the releasability can be improved. . Moreover, a moldability can be improved more by using together 1-10 weight part antiblocking agent per 100 weight part of biodegradable aliphatic polyester. Moreover, hydrolysis resistance can be improved by mix | blending 0.1-10 weight part hydrolysis inhibitor with respect to 100 weight part of biodegradable aliphatic polyester.

It is a partial cross section side view of the pull open cap used for the Example of this invention. It is a bottom view of the cap shown in FIG. 1 of this invention. It is a reference view (bottom view) of a pull open cap having a cutout region having a shape suitable for the present invention.

Explanation of symbols

A Pull open cap 1, 1a Breakable thin part 2, 2a Cut-out area 3 Top wall 4 Finger hook (pull ring)
5 Strut 6, 6a Strut connection 7 Outer cylinder wall 8 Engagement protrusion

Claims (14)

A cap made of a biodegradable aliphatic polyester resin, the cap having a top wall in which a cut-out region is defined by a breakable thin-walled portion, and a finger hook provided in the cut-out region, A cap, wherein the biodegradable aliphatic polyester resin contains 2 to 40 parts by weight of a compound represented by the following general formula (1) per 100 parts by weight of the biodegradable aliphatic polyester .

(When R ¹ represents a group represented by the following general formula (A), R ² represents a group represented by the following general formula (B), and when R ¹ is a benzyl group, R ² represents the following general formula A group represented by the formula (A) or (B) is shown.)

A cap made of a biodegradable aliphatic polyester resin, the cap having a top wall in which a cut-out region is defined by a breakable thin-walled portion, and a finger hook provided in the cut-out region, The biodegradable aliphatic polyester resin is compounded with a compound represented by the following general formula (2).

^{(R 3} is _H, an aromatic acyl group of an aliphatic acyl group, or a _C 6 _{~ 12} of _{^{C 1 ~ 5, R 4,}} R 5, R 6 are all not the same, each following general formula (C) Or represented by the general formula (D))

^{(R 7} represents an alkylene group of _C 1 _{~ 6,} ^{R 8} is _C 1 linear or branched alkyl group of _{~ 10,} C ₆ aryl group _{~ 12,} C _{7 ~} arylalkyl group or _{C 7 15} To ₁₅ alkylaryl groups, and p represents an integer of 0 to 6)

(R 9 is an alkylene group of C 1 ~ 6, R 10 is C 1 linear or branched alkyl group of ~ 10, C 6 aryl group ~ 12, C 7 ~ arylalkyl group or C 7 15 To 15 alkylaryl groups, q represents an integer of 0 to 6) Characterized in that the raw to the biodegradable aliphatic polyester resin, one general formula (2) amount of the compound represented by the biodegradable aliphatic polyester per 100 parts by weight, 2 to 40 parts by weight, The cap according to claim 2 . The blending amount of the compound represented by the general formula (1) or the general formula (2) in the biodegradable aliphatic polyester resin is 10 to 25 parts by weight per 100 parts by weight of the biodegradable aliphatic polyester. The cap according to any one of claims 1 to 3, wherein the cap is characterized. The cap according to any one of claims 1 to 4, wherein the biodegradable aliphatic polyester resin is a polyalkylene alkanoate, a copolymer thereof, or a mixture thereof. The cap according to any one of claims 1 to 5, wherein the biodegradable aliphatic polyester resin is polybutylene succinate, a copolymer thereof, or a mixture thereof. The cap according to any one of claims 1 to 6, wherein the copolymer of polybutylene succinate is polybutylene succinate adipate. The cap according to any one of claims 1 to 7, wherein the biodegradable aliphatic polyester resin or a copolymer thereof has a high molecular weight using a chain extender. 6. The cap according to claim 1, wherein the copolymer of polyalkylene alkanoate is polybutylene adipate terephthalate. The mixture of the polyalkylene alkanoate and a copolymer thereof comprises at least two selected from polybutylene succinate, polybutylene succinate adipate, and polybutylene adipate terephthalate. Cap according to any one of 5 The biodegradable aliphatic polyester resin is characterized in that 0.01 to 5 parts by weight of a fatty acid, a fatty acid amide, or a mixture of a fatty acid and a fatty acid amide is blended per 100 parts by weight of the biodegradable aliphatic polyester. The cap according to any one of claims 1 to 10. The biodegradable aliphatic polyester resin contains 1 to 10 parts by weight of an antiblocking agent per 100 parts by weight of the biodegradable aliphatic polyester. Cap. The biodegradable aliphatic polyester resin is blended with 0.1 to 10 parts by weight of a hydrolysis inhibitor per 100 parts by weight of the biodegradable aliphatic polyester. Cap as described in. The cap according to claim 1, wherein the finger hook portion includes a support column extending upward from the cut region and a pull ring connected to the support column.

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