cap

Abstract

To provide a cap having enhanced impact resistance while having dimensional accuracy and an appearance equivalent to a cap in a conventional technology, and to provide the cap capable of effectively utilizing resources.SOLUTION: A cap is obtained by molding a resin composition containing (A) polypropylene, (B) ethylene-vinyl alcohol copolymer, and (C) acid-modified polypropylene. A content of the (B) component in the resin composition is 0.1 pt.mass or more and 1.0 pt.mass or less with respect to 100 pts.mass of the resin component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a cap. More specifically, it relates to a cap used to seal the contents of a bottle. [Background technology]

[0002] Containers such as tubes and bottles used to hold food, cosmetics, pharmaceuticals, etc., are fitted with synthetic resin caps that can be opened and closed. When the cap is closed, the contents inside the container are sealed and protected, and when opened, the contents can be dispensed and used.

[0003] Such caps often use polypropylene (PP) resin, which has a relatively high melt mass flow rate (MFR), to improve injection moldability.

[0004] However, caps made of PP with such high MFR (Moisture Factor) had insufficient impact resistance. Generally, a high MFR tends to correlate with a low molecular weight, and a higher molecular weight is advantageous for achieving high impact resistance.

[0005] Studies are underway to blend other suitable resins into the caps to impart functionality. For example, Patent Document 1 discloses a container cap made of a blend of PP, ethylene-vinyl alcohol copolymer (EVOH), polyamide resin, and olefin-unsaturated carboxylic acid copolymer, which is described as having excellent gas barrier properties, mechanical strength, appearance, and recyclability. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2000-248131 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, our research has revealed that while blending other resins into a PP cap, as taught in Patent Document 1, may improve certain functionalities, it can also lead to disadvantages such as reduced injection molding accuracy. Therefore, improving functionality through resin blending has both advantages and disadvantages.

[0008] On the other hand, in response to the growing demand for environmentally friendly packaging materials in recent years, there is a need to develop packaging materials using biomass materials, recycled materials, etc., and it is also necessary to blend these materials with existing materials without compromising the functionality of existing products.

[0009] Furthermore, from a safety standpoint, it is desirable for the cap to have as high an impact resistance as possible.

[0010] This invention was made under the circumstances described above. The first object of this invention is to provide a cap that has the same dimensional accuracy and appearance as conventional caps, but with improved impact resistance. The second object of this invention is to provide a cap that contributes to the effective use of resources. [Means for solving the problem]

[0011] The present invention is as follows:

[0012] 《Appearance 1 (A) Polypropylene, (B) Ethylene vinyl alcohol copolymer, and (C) Acid-modified polypropylene A cap made by molding a resin composition containing, The content of component (B) in the resin composition is 0.1 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the resin composition. cap. <Aspect 2> The cap according to Aspect 1, wherein the content of the component (C) in the resin composition is 0.05 parts by mass or more and 0.80 parts by mass or less based on 100 parts by mass of the resin composition. <Aspect 3> wherein the component (A) is (A1) a high-MFR polypropylene having an MFR of 15.0 g / 10 min or more, and (A2) a low-MFR polypropylene having an MFR of 5.0 g / 10 min or less comprises provided that the MFR is a melt mass flow rate measured at a temperature of 230°C and a load of 2.16 kg in accordance with JIS K 6921-2, the cap according to Aspect 1. <Aspect 4> The cap according to Aspect 3, wherein in the resin composition, a ratio of a mass of the component (A2) to a total mass of the component (A1) and the component (A2) is 2.0% by mass or more and 30.0% by mass or less. <Aspect 5> A method for producing the cap according to any one of Aspects 1 to 4, comprising (A) a polypropylene, (B) an ethylene-vinyl alcohol copolymer, and (C) an acid-modified polypropylene comprises injection-molding a resin composition containing the foregoing components, and the content of the component (B) in the resin composition is 0.1 parts by mass or more and 1.0 parts by mass or less based on 100 parts by mass of the resin composition, the production method. <Aspect 6> prior to injection-molding the resin composition, further comprises preparing the resin composition, the preparation of the resin composition comprises mixing a masterbatch containing a part of the component (A), the component (B) and the component (C) with the remainder of the component (A) ,[[-END]] the production method according to Aspect 5. <Aspect 7> wherein a part of the component (A) contained in the masterbatch comprises (A2) a low-MFR polypropylene having an MFR of 5.0 g / 10 min or less, The remainder of component (A) to be mixed with the masterbatch is (A1) high MFR polypropylene having an MFR of 15.0 g / 10 min or more, wherein the MFR is a melt mass flow rate measured at a temperature of 230°C and a load of 2.16 kg in accordance with JIS K 6921-2, The production method according to aspect 6.

Effects of the Invention

[0013] According to the present invention, firstly, there is provided a cap having improved impact resistance while having the same dimensional accuracy and appearance as caps in the prior art. For the cap of the present invention, for example, waste material of multilayer PP bottles may be used as a part of the material. Therefore, secondly, according to the present invention, there is provided a cap that contributes to effective utilization of resources.

Mode for Carrying Out the Invention

[0014] <<Cap>> The cap of the present invention, (A) polypropylene, (B) ethylene-vinyl alcohol copolymer, and (C) acid-modified polypropylene which is a cap formed by molding a resin composition comprising the above components, wherein the content of component (B) in the resin composition is 0.1 part by mass or more and 1.0 part by mass or less based on 100 parts by mass of the resin composition.

[0015] <(A) Polypropylene> The cap of the present invention is a cap formed by molding a resin composition containing the above components (A) to (C) as essential components.

[0016] The resin composition constituting the cap of the present invention contains (A) polypropylene (PP) and a small amount of (B) ethylene vinyl alcohol copolymer (EVOH), which is relatively hard as a synthetic resin. Although (A) PP and (B) EVOH are an immiscible combination, when (C) acid-modified polypropylene (acid-modified PP) is added, component (C) acts as a compatibilizer, and it is believed that the impact resistance of the cap is improved by the high dispersion of hard (B) EVOH in (A) PP.

[0017] Furthermore, the amount of (B)EVOH in the resin composition is small, between 0.1 parts by mass and 1.0 part by mass per 100 parts by mass of the resin composition, and the amount of (C)acid-modified PP is also small, preferably between 0.05 parts by mass and 0.80 parts by mass per 100 parts by mass of the resin composition, as will be described later. Therefore, the dimensional accuracy and good appearance inherent in (A)PP during molding are hardly impaired.

[0018] It is presumed that, through the mechanism described above, the cap of the present invention will have improved impact resistance while maintaining the same dimensional accuracy and appearance as conventional caps. However, the present invention is not bound by any particular theory.

[0019] The components contained in the resin composition that constitutes the cap of the present invention will be described in order below.

[0020] (A) Polypropylene (PP) (A)PP may be a homopolymer of propylene or a copolymer of propylene and another monomer. Other monomers other than propylene can preferably be used. Specifically, for example, α-olefins having 2 or 4 to 10 carbon atoms can be cited, preferably ethylene, 1-butene, 1-pentene, or 1-hexene.

[0021] (A) If PP is a copolymer of propylene and other monomers, the copolymerization can take the form of a block copolymer, a random copolymer, or a mixture thereof. A mixture of a propylene homopolymer and a copolymer of propylene and other monomers is also acceptable.

[0022] The crystal structure of the PP portion may be isotactic, syndiotactic, or atactic.

[0023] (A) The PP is particularly preferably a random copolymer or block copolymer of propylene and ethylene, wherein the crystalline structure of the PP portion is isotactic.

[0024] In the present invention, (A)PP may have a relatively high MFR in order to ensure airtightness and impact resistance. For example, the melt mass flow rate (MFR) measured at a temperature of 230°C and a load of 2.16 kg in accordance with JIS K 6921-2 may be 8.0 g / 10 min or more, 10.0 g / 10 min or more, 12.0 g / 10 min or more, 15.0 g / 10 min or more, 17.0 g / 10 min or more, or 20.0 g / 10 min or more. On the other hand, in order to ensure moldability and heat resistance, the above MFR may be 80.0 g / 10 min or less, 60.0 g / 10 min or less, 50.0 g / 10 min or less, 40.0 g / 10 min or less, 30.0 g / 10 min or less, or 20.0 g / 10 min or less.

[0025] (A) The density of PP is 890 kg / m³ 3 More than 910kg / m 3 The tensile modulus may be approximately 500 MPa to 1,000 MPa.

[0026] (A) The above characteristics relating to PP refer to the characteristics of the mixture as a whole if component (A) is a mixture of two or more types of PP.

[0027] In the present invention, (A)PP is (A1) High MFR polypropylene (high MFR-PP) with an MFR of 15.0g / 10 min or more, and (A2) Low MFR polypropylene (low MFR-PP) with an MFR of 5.0g / 10 minutes or less It may include these, and may consist only of these.

[0028] The above MFR is the melt mass flow rate measured in accordance with JIS K 6921-2 at a temperature of 230°C and a load of 2.16 kg.

[0029] In the present invention, if (A)PP includes (A1) high MFR-PP and (A2) low MFR-PP, it becomes easy to achieve both good dimensional accuracy and appearance and high impact resistance.

[0030] High MFR-PP may be a homopolymer of propylene, or a copolymer of propylene and the other monomers mentioned above. Particularly preferred as high MFR-PP is a random copolymer or block copolymer of propylene and ethylene, where the crystalline structure of the PP portion is isotactic.

[0031] The MFR of high MFR-PP is 15.0 g / 10 min or higher, and may be 17.5 g / 10 min or higher, 20.0 g / 10 min or higher, 22.5 g / 10 min or higher, or 25.0 g / 10 min or higher, and may be 80.0 g / 10 min or lower, 60.0 g / 10 min or lower, 50.0 g / 10 min or lower, 40.0 g / 10 min or lower, or 30.0 g / 10 min or lower.

[0032] The density of high MFR-PP is 895 kg / m³ 3 More than 910kg / m 3 The tensile modulus may be approximately 750 MPa to 1,000 MPa.

[0033] Low MFR-PP may be a homopolymer of propylene, or a copolymer of propylene with the other monomers mentioned above. Particularly preferred as low MFR-PP is a random copolymer or block copolymer of propylene and ethylene, where the crystalline structure of the PP portion is isotactic.

[0034] The MFR of low MFR-PP is 5.0 g / 10 min or less, and may be 4.0 g / 10 min or less, 3.5 g / 10 min or less, 3.0 g / 10 min or less, 2.5 g / 10 min or less, or 2.0 g / 10 min or less, and may be 0.5 g / 10 min or more, 0.7 g / 10 min or more, 1.0 g / 10 min or more, 1.2 g / 10 min or more, or 1.5 g / 10 min or more.

[0035] The density of low MFR-PP is 880 kg / m³ 3 More than 895kg / m 3 It is acceptable to have a degree of elasticity such that the tensile modulus is approximately 200 MPa to 700 MPa.

[0036] In the present invention, the blending ratio of (A1) high-MFR-PP and (A2) low-MFR-PP in (A)PP is the ratio of the mass of (A2) low-MFR-PP to the total mass of (A1) high-MFR-PP and (A2) low-MFR-PP. From the viewpoint of improving impact resistance, it may be 2.0% by mass or more, 5.0% by mass or more, 7.0% by mass or more, 10.0% by mass or more, or 12.0% by mass or more, and from the viewpoint of ensuring good dimensional accuracy and appearance, it may be 30.0% by mass or less, 25.0% by mass or less, 20.0% by mass or less, 15.0% by mass or less, 12.0% by mass or less, or 10.0% by mass or less.

[0037] In the present invention, (A)PP may or may not contain PP other than (A1) high MFR-PP and (A2) low MFR-PP.

[0038] (B) Ethylene vinyl alcohol copolymer (EVOH) In the present invention, (B)EVOH is a copolymer of ethylene and vinyl alcohol. The copolymerization ratio of ethylene in (B)EVOH may be 20 mol% or more and 47 mol% or less, and may be 25 mol% or more and 32 mol% or less.

[0039] (B)EVOH may be obtained, for example, by saponifying a copolymer of ethylene and vinyl carboxylate (e.g., vinyl acetate). In this case, the degree of saponification of (B)EVOH may be 75 mol% or more, 80 mol% or more, 85 mol% or more, 90 mol% or more, or 95 mol% or more, or it may be a fully saponified product with a degree of saponification of 100 mol%. Here, the degree of saponification refers to the ratio of the number of moles of vinyl alcohol units to the total number of moles of vinyl alcohol units and vinyl carboxylate units in (B)EVOH.

[0040] (B) For EVOH, the melt mass flow rate (MFR) measured in accordance with JIS K 6921-2 at a temperature of 190°C and a load of 2.16 kg may be approximately 1.5 g / 10 min to 8.0 g / 10 min. (B) The density of EVOH is 1,100 kg / m³. 3 More than 1,200kg / m 3 The following level is acceptable.

[0041] (C) Acid-modified polypropylene (acid-modified PP) In the present invention, (C) acid-modified PP may be obtained by, for example, graft polymerization of an unsaturated carboxylic acid onto a base resin PP.

[0042] The base resin PP may be a homopolymer of propylene, or a copolymer of propylene and the other monomers mentioned above.

[0043] The unsaturated carboxylic acid grafted onto the PP base resin may be one or more selected from, for example, acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, crotonic acid, citraconic acid, and their acid anhydrides.

[0044] The grafting rate of unsaturated carboxylic acid in (C) acid-modified PP may be evaluated by oxidation measured in accordance with JIS K 0070. This oxidation refers to the number of milligrams (mg) of potassium hydroxide required to neutralize acid groups and acid anhydride groups in 1 g of (C) acid-modified PP. The acid value of (C) acid-modified PP may be, for example, approximately 3.5 to 50 inclusive.

[0045] For (C) acid-modified PP, the melt mass flow rate (MFR) measured at a temperature of 230°C under a load of 2.16 kg in accordance with JIS K 6921-2 may be approximately 15.0 g / 10 min to 80.0 g / 10 min inclusive. The density of (C) acid-modified PP is 8700 kg / m 3 to 890 kg / m 3 inclusive.

[0046] <Optional Components> The resin composition constituting the cap of the present invention may contain optional components in addition to the above-mentioned components (A) to (C). The optional component may be, for example, one or more selected from among pigments, antioxidants, antistatic agents, thickeners, defoamers, surface modifiers, fillers, and the like.

[0047] <Blending Ratios of Components in Resin Composition> Based on 100 parts by mass of the resin composition, the content of (A) PP may be 80 parts by mass or more, 85 parts by mass or more, 90 parts by mass or more, or 95 parts by mass or more from the viewpoint of ensuring good moldability; and may be 99 parts by mass or less, 98 parts by mass or less, 95 parts by mass or less, 93 parts by mass or less, or 90 parts by mass or less from the viewpoint of obtaining the advantages achieved by blending components (B) and (C). When (A) PP is a mixture of multiple types of PP, the above amount of (A) PP is a value based on the total mass of all PP types.

[0048] The content of (B)EVOH per 100 parts by mass of the resin composition is 0.1 parts by mass or more, and may be 0.2 parts by mass or more, 0.3 parts by mass or more, 0.4 parts by mass or more, or 0.5 parts by mass or more, from the viewpoint of improving the impact resistance of the cap. Furthermore, from the viewpoint of ensuring good dimensional accuracy and appearance, this amount is 1.0 part by mass or less, and may be 0.8 parts by mass or less, 0.6 parts by mass or less, 0.5 parts by mass or less, or 0.4 parts by mass or less.

[0049] The content of (C) acid-modified PP per 100 parts by mass of the resin composition may be 0.05 parts by mass or more, 0.10 parts by mass or more, 0.15 parts by mass or more, or 0.20 parts by mass or more, from the viewpoint of ensuring compatibility between (A) PP and (B) EVOH. Furthermore, from the viewpoint of ensuring good dimensional accuracy and appearance, this amount may be 0.80 parts by mass or less, 0.60 parts by mass or less, 0.50 parts by mass or less, 0.40 parts by mass or less, or 0.30 parts by mass or less.

[0050] As described above, the resin composition constituting the cap of the present invention may contain optional components in addition to components (A) to (C). The content of optional components per 100 parts by mass of the resin composition may be 10 parts by mass or less, 5 parts by mass or less, 3 parts by mass or less, or 1 part by mass or less, or the resin composition may not contain any optional components.

[0051] <Cap shape> The shape of the cap may be any shape that fits the opening of the container it is intended to be used with. The cap may, for example, have a disc-shaped top plate and a peripheral wall around the outer circumference of the top plate. The cap may also have screw grooves, engaging protrusions, engaging recesses, etc., for attaching to the opening of the container, and may further have an anti-tampering ring, etc.

[0052] <Optional elements of the cap> The cap may consist only of a portion formed from the above-mentioned resin composition, or it may have a portion formed from the above-mentioned resin composition along with a portion formed from another material. The portion formed from another material may be, for example, a packing made from an ethylene-α-olefin copolymer.

[0053] 《Method of manufacturing a cap》 The cap of the present invention may be manufactured by any method, as long as it has the above-described configuration.

[0054] The cap of the present invention is, for example, (A) Polypropylene (PP), (B) Ethylene vinyl alcohol copolymer (EVOH), and (C) Acid-modified polypropylene (acid-modified PP) This includes injection molding a resin composition containing the following: The content of component (B) in the above resin composition is 0.1 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the resin composition. It may be manufactured according to the manufacturing method.

[0055] The types and amounts of each component contained in the above resin composition may be appropriately set according to the composition of the cap to be manufactured. Therefore, for details of the resin composition for manufacturing the cap of the present invention, the above description of the resin composition constituting the cap of the present invention can be used as a reference.

[0056] For example, (A)PP in the resin composition for manufacturing the cap of the present invention is (A1) High MFR polypropylene (high MFR-PP) with an MFR of 15.0g / 10 min or more, and (A2) Low MFR polypropylene (low MFR-PP) with an MFR of 5.0g / 10 minutes or less It may include.

[0057] The injection molding of the cap from the above resin composition may be carried out by known methods or by methods with any modifications thereto as can be made by those skilled in the art. Specifically, general conditions for injection molding of polypropylene resin may be used, for example, injection molding at a temperature of 180°C to 280°C, or 200°C to 250°C.

[0058] The above resin composition is, for example, (A) A masterbatch containing a portion of PP, (B) EVOH and (C) acid-modified PP, (A) Remaining portion of PP and It may be prepared by a method that includes mixing the following.

[0059] In this case, a portion of the (A)PP contained in the masterbatch may include (A2) low-MFR-PP, and the remainder of the (A)PP mixed with the masterbatch may be (A1) high-MFR-PP.

[0060] In this embodiment, waste materials from multi-layer PP bottles can be used as a source for (A2) low MFR-PP, (B) EVOH, and (C) acid-modified PP contained in the masterbatch, which is advantageous in terms of environmental protection and efficient use of resources.

[0061] A multilayer PP bottle may be, for example, a PP bottle molded by a direct blow molding method. Specifically, the outermost and innermost layers may be made of PP resin, and the intermediate layers may include an adhesive layer and a barrier resin layer. Relatively hard PP is used for the outermost and innermost layers from the viewpoint of suitability for direct blow molding, and this often corresponds to (A2) low MFR-PP in the present invention. EVOH is used for the barrier layer as a material that is difficult for gases, solvents, and chemical substances to permeate, and this often corresponds to (B) EVOH in the present invention. Acid-modified PP is used for the adhesive layer as a material with high adhesion between PP and polar resins, and this often corresponds to (C) acid-modified PP in the present invention.

[0062] Furthermore, the mass ratio of the adhesive layer to the barrier resin layer in the multilayer PP bottle is not inconsistent with the recommended range for the mass ratio of (B) EVOH to (C) acid-modified PP in the resin composition for manufacturing the cap of the present invention.

[0063] Therefore, by using waste material from multi-layer PP bottles as a masterbatch and adding the remainder of (A)PP, preferably (A1) high-MFR-PP, a resin composition for manufacturing the cap of the present invention can be easily prepared.

[0064] A masterbatch may be prepared by adding a portion of (A1) high-MFR-PP to waste material from multi-layer PP bottles, and then adding the remainder of (A1) high-MFR-PP to this masterbatch to prepare the resin composition for manufacturing the cap of the present invention. [Examples]

[0065] Example 1 (1) Preparation of the masterbatch As a masterbatch precursor containing components (A2), (B), and (C), crushed waste material from multi-walled PP blow-molded bottles was used. The component composition of this waste material was as follows: (A2) Ingredients: Low MFR-PP (MFR: 1.7g / 10min (JIS K 6921-2, 230℃, 2.16kg), Density: 890kg / m 3 ), 93.5% by mass (B) Component: EVOH (MFR: 4.1g / 10min (JIS K 6921-2, 190℃, 2.16kg), Density: 1,180kg / m 3 ), 3.9% by mass (C) Ingredients: Maleic anhydride modified PP (MFR: 25g / 10 min (JIS K 6921-2), Density: 880kg / m³) 3 ), 2.6% by mass

[0066] (A1) As an ingredient, random copolymer type PP manufactured by Sun Allomer Co., Ltd. (product name "PM931V" (MFR: 25g / 10 min (JIS K 6921-26921-2, 230℃, 2.16kg), density: 900kg / m³) 3), pellets) 40 parts by mass, and As a masterbatch precursor containing components (A2), (B), and (C), 60 parts by mass of the crushed PP blow bottle waste material mentioned above. After dry blending, the mixture was pelletized using a commercially available twin-screw extruder to produce a masterbatch pellet containing a portion of component (A1), as well as components (A2), (B), and (C). The component composition of this masterbatch was as follows: (A1) Component: 40.00% by mass (A2) Component: 56.10% by mass (B) Component: 2.34% by mass (C) Component: 1.56% by mass

[0067] (2) Manufacturing of caps (A1) Component: 91.67 parts by mass of "PM931V" manufactured by Sun Allomer Co., Ltd., and 8.33 parts by mass of the masterbatch prepared above These were mixed. The resulting mixture contained 5.00% by mass of the PP blow-molded bottle waste material used as the masterbatch precursor.

[0068] The above mixture was placed in an injection molding machine equipped with a mold for manufacturing caps, and kneading and injection molding were performed at a temperature range of 200°C to 250°C to form caps weighing 4g each. The caps had a disc-shaped top plate and a peripheral wall around the outer circumference of the top plate, with screw races on the inner surface of the peripheral wall. The mold used for manufacturing the caps was capable of molding 12 caps per shot. Ten injection moldings were performed, yielding a total of 120 caps.

[0069] (3) Evaluation of the cap The obtained caps were evaluated as follows:

[0070] i) Mass Each of the obtained caps was weighed using a precision balance, a "benchtop analytical balance," manufactured by Shimadzu Corporation, and the average value (Ave), maximum value (Max), minimum value (Min), and the difference between the maximum and minimum values ​​(R) were determined.

[0071] ii) Leakage test Five of the obtained caps (60 caps) were screwed onto tube containers filled with 60g of a 0.1% by mass surfactant aqueous solution. With the caps facing downwards, they were left standing at room temperature for 24 hours, and then visually inspected for leakage. The results were evaluated according to the following criteria. If no caps were found to be leaking: A (Good) If one or more caps are found to be leaking: B (Defective)

[0072] iii) Airtightness test For each of the 60 caps obtained (5 shots), holes were drilled in the top plate and pressurizing pipes were connected, and each cap was screwed onto a tube container. These capped tube containers were submerged in water, and the inside of the tube containers was pressurized to 0.1 MPa (absolute pressure) through the pressurizing pipes. The presence or absence of air leaks was visually observed and evaluated according to the following criteria. If no caps were found to have air leaks: A (Good) If one or more caps are found to be leaking air: B (Defective)

[0073] iv) Drop test Five sets (60 caps) of the obtained caps were each screwed onto a tube container filled with 50g of water. After cooling to 5°C, they were dropped from a height of 1m onto a concrete floor with the caps facing downwards. The condition of the caps was then visually observed and evaluated according to the following criteria. If no cracked caps were found: A (Good) If one or more caps are cracked: B (Defective)

[0074] v) Crash Test Six of the obtained caps were placed on a metal floor with their tops facing upwards, and a disc-shaped weight was dropped onto them from a height of 0.3 m. Caps that did not break in the first weight drop test were subjected to a second test using the same method. The number of caps that did not break in the first test and the number of caps that did not break in the second test were then determined.

[0075] The results are shown in Table 2.

[0076] Examples 2 and 3 In "(2) Cap Manufacturing," the caps were manufactured and evaluated in the same manner as in Example 1, except that the mixing ratio of component (A1) and the masterbatch was changed as shown in Table 1. The evaluation results are shown in Table 2.

[0077] Examples 4 and 5 In "(1) Preparation of Masterbatch," 40 parts by mass of component (A1) and 60 parts by mass of crushed PP blow bottle waste were dry-blended and then crushed to obtain the crushed material, which was used as the masterbatch. In "(2) Production of Caps," the mixing ratio of component (A1) and masterbatch was changed as shown in Table 1, but the caps were produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0078] Comparative Example 1 In "(2) Cap Manufacturing," the caps were manufactured and evaluated in the same manner as in Example 1, except that a masterbatch was not used and only component (A1) was used. The evaluation results are shown in Table 2.

[0079] [Table 1]

[0080] [Table 2]

[0081] From the above results, it was verified that the cap of the present invention has substantially the same molding accuracy as the comparative example cap made of PP, while having improved crush resistance.

Claims

1. (A) Polypropylene, (B) Ethylene vinyl alcohol copolymer, and (C) Acid-modified polypropylene A cap made by molding a resin composition containing, The above component (A) (A1) High MFR polypropylene of 15.0 g / 10 min or more, (A2) Low MFR polypropylene with an MFR of 5.0 g / 10 min or less Includes, However, the MFR is the melt mass flow rate measured in accordance with JIS K 6921-2 at a temperature of 230°C and a load of 2.16 kg. The content of component (B) in the resin composition is 0.1 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the resin composition. cap.

2. The cap according to claim 1, wherein the content of component (C) in the resin composition is 0.05 parts by mass or more and 0.80 parts by mass or less per 100 parts by mass of the resin composition.

3. The cap according to claim 1, wherein in the resin composition, the ratio of the mass of component (A2) to the total mass of component (A1) and component (A2) is 2.0% by mass or more and 30.0% by mass or less.

4. A method for manufacturing a cap according to any one of claims 1 to 3, (A) Polypropylene, (B) Ethylene vinyl alcohol copolymer, and (C) Acid-modified polypropylene This includes injection molding a resin composition containing the following: The above-mentioned component (A) is, (A1) High MFR polypropylene of 15.0 g / 10 min or more, (A2) Low MFR polypropylene with an MFR of 5.0 g / 10 min or less Includes, However, the MFR is the melt mass flow rate measured in accordance with JIS K 6921-2 at a temperature of 230°C and a load of 2.16 kg. The content of component (B) in the resin composition is 0.1 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the resin composition. Manufacturing method.

5. Before injection molding the aforementioned resin composition, The process further includes preparing the aforementioned resin composition. The preparation of the resin composition is A masterbatch containing a portion of component (A), as well as component (B) and component (C), The remainder of component (A) and Including mixing The manufacturing method according to claim 4.

6. A portion of component (A) contained in the masterbatch contains (A2) low-MFR polypropylene with an MFR of 5.0 g / 10 min or less. The remainder of component (A) to be mixed with the masterbatch is (A1) high-MFR polypropylene with an MFR of 15.0 g / 10 min or more. The manufacturing method according to claim 5.

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