RESIN COMPOSITION, FILM, MULTILAYER BODY, AND PACKAGING BAG FOR MEDICAL USE

Abstract

A resin composition may include: an ethylene-vinyl acetate copolymer (A); and a propylene-based resin (B). The melt flow rate (MFR: 190° C., 2.16 kg) MFR (A) of the ethylene-vinyl acetate copolymer (A) and the melt flow rate (MFR: 190° C., 2.16 kg) MFR (B) of the propylene-based resin (B) may satisfy relational expression (i)

4 g/10 min≤MFR(A)−MFR(B)≤35 g/10 min  (i).

The resin composition may have an endothermic peak at 120 to 170° C. in differential scanning calorimetry and a heat of fusion in a range of from 15 to 40 mJ/mg at 120 to 170° C.:

Claims

1. A resin composition, comprising: an ethylene-vinyl acetate copolymer (A); and a propylene-based resin (B), wherein the melt flow rate (MFR: 190° C., 2.16 kg) MFR (A) of the ethylene-vinyl acetate copolymer (A) and the melt flow rate (MFR: 190° C., 2.16 kg) MFR (B) of the propylene-based resin (B) satisfy relational expression (i):
4 g/10 min≤MFR(A)−MFR(B)≤35 g/10 min  (i), and wherein the resin composition has an endothermic peak at 120 to 170° C. in differential scanning calorimetry and has a heat of fusion in a range of from 15 to 40 mJ/mg at 120 to 170° C.

2. The resin composition of claim 1, further comprising: a polyamide resin (C).

3. The resin composition of claim 2, wherein the ethylene-vinyl acetate copolymer (A) is present in an amount of from 25 to 38% by mass, wherein the propylene-based resin (B) is present in an amount of from 47 to 60% by mass, and wherein the polyamide resin (C) is present in an amount of from 2 to 15% by mass wherein a sum of the amounts of the ethylene-vinyl acetate copolymer (A), the content of the propylene-based resin (B), and the content of the polyamide resin (C) is 100% by mass.

4. The resin composition of claim 1, wherein light absorbance in a wavelength range of 220 to 350 nm is 0.2 or less in a UV spectrum test described in The Japanese Pharmacopoeia Seventeenth Edition, General Tests, 7.02 Test Methods for Plastic Containers, Extractable substances.

5. The resin composition of claim 1, which is suitable for dielectric heat welding.

6. A film, comprising: the resin composition of claim 1.

7. A multilayer body prepared by stacking the film of claim 6 on a substrate.

8. A packaging bag suitable for medical use, comprising: the film of claim 6.

9. A packaging bag suitable for medical use, comprising the multilayer body of claim 7.

10. A resin composition suitable for dielectric heat welding, comprising: an ethylene-vinyl acetate copolymer (A) satisfying conditions (A-i) to (A-ii) below; and a propylene-based resin (B) satisfying conditions (B-i) to (B-ii) below: (A-i) a melt flow rate (MFR: 190° C., 2.16 kg) is in a range of from 7 to 50 g/10 min; (A-ii) a content of a constitutional unit derived from vinyl acetate is in a range of from 25 to 45% by mass; (B-i) a melt flow rate (MFR: 190° C., 2.16 kg) is in a range of from 0.05 to 6.5 g/10 min; and (B-ii) a value obtained by multiplying a heat of fusion of the propylene-based resin (B) determined from an integral value at −10 to 200° C. using a DSC (differential scanning calorimeter) by the content of the propylene-based resin (B) among resin components comprised in the resin composition for dielectric heat welding is in a range of from 15 to 40 mJ/mg, wherein when the propylene-based resin (B) comprises two or more propylene-based resins (B), a sum of values obtained by multiplying the heats of fusion of the two or more propylene-based resins (B) by the contents thereof is in a range of from 15 to 40 mJ/mg.

11. The resin composition of claim 10, further comprising: a polyamide resin (C).

12. The resin composition of claim 11, wherein the ethylene-vinyl acetate copolymer (A) is present in an amount of from 25 to 38% by mass, wherein the propylene-based resin (B) is present in an amount of from 47 to 60% by mass, and wherein the polyamide resin (C) is present in an amount of from 2 to 15% by mass, wherein a sum of the content of the ethylene-vinyl acetate copolymer (A), the content of the propylene-based resin (B), and the content of the polyamide resin (C) is 100% by mass.

13. The resin composition of claim 10, wherein light absorbance in a wavelength range of 220 to 350 nm is 0.2 or less in a UV spectrum test described in The Japanese Pharmacopoeia Seventeenth Edition, General Tests, 7.02 Test Methods for Plastic Containers, Extractable substances.

14. A film, comprising: the resin composition of claim 10.

15. A multilayer body prepared by stacking the film of claim 14 on a substrate.

16. A packaging bag suitable for medical use, comprising: the film of claim 14.

17. A packaging bag suitable for medical use, comprising: the multilayer body of claim 15.

Description

EXAMPLES

[0119] The present invention will be described more specifically by way of Examples and Comparative Examples. However, the present invention is not limited to the following Examples so long as they fall within the scope of the invention. Various production conditions and the values of evaluation results in the following Examples have meanings as preferred upper or lower limits in the embodiments of the present invention, and preferred ranges may be ranges defined by combinations of the above-described upper or lower limit values and values in the following Examples or combinations of the values in the following Examples.

[Raw Materials Used]

[0120] Raw materials used in the following Examples and Comparative Examples are as follows.

<EVA (A)>

[0121] EVA (A-1): Product name “EVAFLEX EV150” manufactured by Dupont-Mitsui Polychemicals Co., Ltd.

[0122] MFR (190° C., 2.16 kg): 30 g/10 min

[0123] Vinyl acetate content: 33% by mass [0124] EVA (A-2): Product name “EVAFLEX EV260” manufactured by Dupont-Mitsui Polychemicals Co., Ltd.

[0125] MFR (190° C., 2.16 kg): 6 g/10 min

[0126] Vinyl acetate content: 28% by mass [0127] EVA (A-3): Product name “EVAFLEX EV270” manufactured by Dupont-Mitsui Polychemicals Co., Ltd.

[0128] MFR (190° C., 2.16 kg): 1 g/10 min

[0129] Vinyl acetate content: 28% by mass

<Propylene-Based Resin (B)>

[0130] Propylene-based resin (B-1): Product name “TAFMER PN9060” manufactured by Mitsui Chemicals, Inc.

[0131] MFR (190° C., 2.16 kg): 3 g/10 min

[0132] Heat of fusion: 15 mJ/mg [0133] Propylene-based resin (B-2): Product name “WELNEX RFG4VM” manufactured by Japan Polypropylene Corporation

[0134] MFR (190° C., 2.16 kg): 3 g/10 min

[0135] Heat of fusion: 40 mJ/mg [0136] Propylene-based resin (B-3): Product name “ZELAS 7025” manufactured by Mitsubishi Chemical Corporation

[0137] MFR (190° C., 2.16 kg): 0.8 g/10 min

[0138] Heat of fusion: 63 mJ/mg [0139] Propylene-based resin (B-4): The propylene-based resin (B-4) was obtained by preparing 100 parts by mass of “WELNEX RFG4VM (product name)” manufactured by Japan Polypropylene Corporation and 0.04 parts by mass of “PERHEXA 25B (product name)” manufactured by NOF CORPORATION, mixing them, then melt-kneading the mixture using a single screw extruder (screw diameter: 50 mm, temperature: 230° C., ejection amount: 25 kg/hour), extruding the resulting mixture from a die into a strand form, and cutting the extrudate (this resin is denoted as “PP-1” in Tables 1 and 2).

[0140] The results of evaluation of the material obtained are as follows.

[0141] MFR (190° C., 2.16 kg): 14 g/10 min

[0142] Heat of fusion: 40 mJ/mg [0143] Propylene-based resin (B-5): The propylene-based resin (B-5) was obtained using the same procedure as that for the propylene-based resin (B-4) except that the amount of “PERHEXA 25B (product name)” manufactured by NOF CORPORATION was changed to 0.03 parts by mass (this resin is denoted as “PP-2” in Tables 1 and 2).

[0144] The results of evaluation of the material obtained are as follows.

[0145] MFR (190° C., 2.16 kg): 10 g/10 min

[0146] Heat of fusion: 40 mJ/mg

<Polyamide Resin (C)>

[0147] Polyamide resin (C): Polyamide 6, product name “Novamid 1020J” manufactured by DSM

<Acrylic-Based Elastomer>

[0148] Acrylic-based elastomer: Acrylic-based elastomer, product name “Kurarity LA4285” manufactured by KURARAY Co., Ltd.

Example 1

1) Production of Resin Composition Sheet

[0149] An EVA (A) and a propylene-based resin (B) shown in Table 1 were used at ratios shown in Table 1 and dry-blended. A compound-sheet simultaneous forming machine obtained by combining a co-rotating fully intermeshing twin screw extruder “KZW15-45MG-NH” manufactured by TECHNOVEL CORPORATION and a single-layer T-die unit was used to obtain a single-layer sheet having a thickness of 0.5 mm (hereinafter referred to as a “weldable sheet”) under the conditions of a cylinder temperature of 240° C., a screw rotation speed of 250 rpm, and a take-up speed of 1 m/min.

2) Production of Polyvinyl Chloride Sheet

[0150] A soft vinyl chloride sheet “product No. 107-16811” manufactured by KOKUGO Co., Ltd. was subjected to compression molding at 190° C. to thereby produce a PVC sheet having a thickness of 0.5 mm.

3) Presence or Absence of Endothermic Peak of Resin Composition at 120 to 170° C. and Measurement of Heat of Fusion by DSC

[0151] The endothermic peak of the resin composition and its heat of fusion were measured using DSC6220 (manufactured by Seiko Instrument Inc.) according to the following procedure.

[0152] First, 5.0 mg of a sample was placed in an aluminum-made sample container to set the sample. Next, the sample was heated from 40° C. to 260° C. at 10° C./min in a nitrogen atmosphere. When the temperature had reached 260° C., the sample was held at 260° C. for 3 minutes to erase thermal history. Next, the sample was cooled from 260° C. to −10° C. at 10° C./min and held at −10° C. for 3 minutes. Then the sample was again heated from −10° C. to 260° C. at 10° C./min. A DSC curve during the second heating was selected, and the endothermic peak temperature during the second heating was determined using an analysis program in TA7000 (manufactured by Seiko Instrument Inc.). The amount of the endothermic heat of the endothermic peak at 120 to 170° C. during the second heating was used as the heat of fusion.

4) Measurement of Heat of Fusion of Propylene-Based Resin (B) and Computation of Heat of Fusion Due to Propylene-Based Resin (B) in Resin Composition

[0153] The heat of fusion of the propylene-based resin (B) was measured using DSC6220 (manufactured by Seiko Instrument Inc.) as follows. A sample was initially heated to 200° C. to erase thermal history and then cooled to −10° C. at a cooling rate of 10° C./min. The sample was again heated at a heating rate of 10° C./min to measure an endothermic peak, and the integral value of the endothermic peak was determined. The unit is mJ/mg.

[0154] The heat of fusion due to the propylene-based resin (B) in the resin composition was determined by multiplying the measured heat of fusion by the content of the propylene-based resin (B).

[0155] For example, in Example 3 described later, since the propylene-based resin (B-2) having a heat of fusion of 40 mJ/mg was used in an amount of 65% by mass, 40×0.65=26 mJ/mg was used.

[0156] When a plurality of propylene-based resins (B) are used, the heat of fusion due to the propylene-based resins (B) in the resin composition is the sum of the heats of fusion of the propylene-based resins (B-1) to (B-3) multiplied by their respective contents. For example, in Example 1, since 45% by mass of the propylene-based resin (B-1) having a heat of fusion of 15 mJ/mg and 20% by mass of the propylene-based resin (B-3) having a heat of fusion of 63 mJ/mg were used, 15×0.45+63×0.2=19.35 was used.

[0157] Values rounded to the nearest whole numbers are shown in Table 1.

5) Evaluation of Weldability Using High-Frequency Welder

5-1) Capability to Weld Weldable Sheet to PVC Sheet

[0158] The weldable sheet having a thickness of 0.5 mm and the PVC sheet having a thickness of 0.5 mm were stacked one on another and sandwiched between two Teflon sheets, and a high-frequency welder “type YPO-5” manufactured by Yamamoto Vinita Co., Ltd. was used to weld the sheets under the conditions of a current of 0.5 A, a time of 0.5 seconds, and a pressure of 0.2 MPa. When the welded sheets could be separated from each other by hand, a fail rating was given (this is denoted as NG in Tables 1 and 2). When the welded sheets could not be separated from each other by hand and any of the sheets was broken, a pass rating was given (this is denoted as OK in Tables 1 and 2).

5-2) Capability to Weld Weldable Sheets Together

[0159] Two weldable sheets having a thickness of 0.5 mm were stacked one on another and sandwiched between two Teflon sheets, and a high-frequency welder “type YPO-5” manufactured by Yamamoto Vinita Co., Ltd. was used to weld the sheets under the conditions of a current of 0.5 A, a time of 0.5 seconds, and a pressure of 0.2 MPa. When the welded sheets could be separated from each other by hand, a fail rating was given (this is denoted as NG in Tables 1 and 2). When the welded sheets could not be separated from each other by hand and any of the sheets was broken, a pass rating was given (this is denoted as OK in Tables 1 and 2).

6) Evaluation of Heat Resistance

[0160] Two weldable sheet having a thickness of 0.5 mm were stacked one on another and cut into 3 cm square pieces. Each cut piece was sandwiched between 350 g glass plates, and the state of the cut piece was controlled in a Geer oven at a set temperature of 70° C. or 100° C. for 30 minutes. After the 3 cm square sheets had been cooled, whether the sheets could be separated from each other by hand was checked. When the sheets were fused and could not be separated from each other or underwent cohesive delamination, a fail rating was given (this is denoted as NG in Tables 1 and 2). When the sheets could be separated from each other by hand and no change was found in the appearance of the separated sheets, a pass rating was given (this is denoted as OK in Tables 1 and 2).

[0161] When the heat resistance at 70° C. is rated pass, the weldable sheets can be used for applications that require heat resistance in, for example, a sterilization step.

[0162] More preferably, the weldable sheets are heat resistant at 100° C. because their range of application is widened.

7) Evaluation of Sheet Formability

[0163] Sheet formability when the single-layer sheet having a thickness of 0.5 mm was formed in 1) Production of the resin composition sheet was rated as follows. When the rating was A, B, or C, the sheet formability was judged as pass. Among the A, B, and C ratings, the rating A means that the sheet formability is highest, and the rating B means that the sheet formability is second highest. The rating C means that the sheet formability is third highest. The D rating means that the sheet formability is poor and judged as fail.

[0164] A: The sheet can be formed stably without any problems.

[0165] B: Although the sheet can be formed, its thickness is uneven in the TD (Transverse Direction).

[0166] C: Although the sheet can be formed, its thickness is uneven in the MD (Machine Direction).

[0167] D: Although the sheet can be formed, the sheet adheres to a cooling roll and cannot be formed stably.

8) Evaluation of UV Absorbance

[0168] When the ratings in evaluation 5) to evaluation 7) were good, a test in “The Japanese Pharmacopoeia Seventeenth Edition, General Tests, 7.02 Test Methods for Plastic Containers, 2. Requirements for plastic containers for aqueous injections, 2.1. Polyethylene or polypropylene containers for aqueous injections, (8) Extractable substances, (iv) UV spectrum” was performed using the weldable sheet having a thickness of 0.5 mm in a test area of 1200 cm.sup.2 under the extraction condition of 70° C.×24 hours. When the absorbance was 0.2 or less in the wavelength range of 220 to 350 nm, a pass rating was given (this is denoted as OK in Tables 1 and 2). When the absorbance was more than 0.2 in the wavelength range of 220 to 350 nm, a fail rating was given (this is denoted as NG in Tables 1 and 2).

Examples 2, 3, 8, and 91

[0169] Sheets were obtained in the same manner as in Example 1 except that an EVA (A) and a propylene-based resin (B) shown in Table 1 were used at ratios shown in Table 1, and the sheets obtained were rated in the same manner as in Example 1.

Examples 4 to 7

[0170] Sheets were obtained in the same manner as in Example 1 except that an EVA (A), a propylene-based resin (B), and the polyamide resin (C) shown in Table 1 were used at ratios shown in Table 1, and the sheets obtained were rated in the same manner as in Example 1.

Comparative Example 1

[0171] A sheet was obtained in the same manner as in Example 1 except that only the acrylic-based elastomer was used, and the sheet obtained was rated in the same manner as in Example 1.

Comparative Examples 2 to 4

[0172] Sheets were obtained in the same manner as in Example 1 except that an EVA (A) or a propylene-based resin (B) shown in Table 2 was used alone, and the sheets obtained were rated in the same manner as in Example 1.

Comparative Examples 5 to 9

[0173] Sheets were obtained in the same manner as in Example 1 except that an EVA (A) and a propylene-based resin (B) shown in Table 2 were used at ratios shown in Table 2, and the sheets obtained were rated in the same manner as in Example 1.

Comparative Example 10

[0174] A sheet was obtained in the same manner as in Example 1 except that the acrylic-based elastomer, an EVA (A), and a propylene-based resin (B) shown in Table 2 were used at ratios shown in Table 2, and the sheet obtained was rated in the same manner as in Example 1.

[0175] The results obtained in Examples 1 to 9 and Comparative Examples 1 to 10 above are summarized in Tables 1 and 2.

TABLE-US-00001 TABLE 1 Example Example Example Example Example Example Example Example Example Unit 1 2 3 4 5 6 7 8 9 Composi- EVA(A) EV150 A-1 % by mass 35 35 35 35 35 35 35 35 35 tion EV260 A-2 % by mass EV270 A-3 % by mass Propylene- PN9060 B-1 % by mass 45 35 35 25 15 5 based resin (B) RFG4VM B-2 % by mass 65 7025 B-3 % by mass 20 30 20 30 40 50 PP-1 B-4 % by mass 65 PP-2 B-5 % by mass 65 Polyamide 1020J C % by mass 10 10 10 10 resin (C) Acrylic- LA4285 — % by mass based elastomer MFR(A) g/10 min 30 30 30 30 30 30 30 30 30 MFR(B) g/10 min 2 2 3 2 2 1 1 14 10 MFR(A)-MFR(B) g/10 min 28 28 27 28 28 29 29 16 20 Peak temperature at 120 to ° C. 162 163 128 163 163 163 163 128 128 170° C. in DSC measurement Heat of fusion of peak at 120 to mJ/mg 19 24 26 18 23 27 32 26 26 170° C. in DSC measurement Heat of fusion due to propylene- mJ/mg 19 24 26 18 23 27 32 26 26 based resin (B) in resin composition Weldability using PVC sheet — OK OK OK OK OK OK OK OK OK high-frequency Weldable — OK OK OK OK OK OK OK OK OK welder sheets Heat resistance 70° C. — OK OK OK OK OK OK OK OK OK 100° C. — NG NG OK NG NG OK OK OK OK Sheet formability — A A A A A A A C B UV absorbance — OK OK OK OK OK OK OK OK OK

TABLE-US-00002 TABLE 2 Com- Com- Com- Com- Com Com- Com- Com- Com- Com- par- par- par- par- par- par- par- par- par- par- ative ative ative ative ative ative ative ative ative ative Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple ple ple ple ple Unit 1 2 3 4 5 6 7 8 9 10 Com- EVA (A) EV150 A-1 % by mass 100 35 65 35 20 position EV260 A-2 % by mass 35 EV270 A-3 % by mass 35 Propylene- PN9060 B-1 % by mass 100 65 35 65 65 40 based resin RFG4VM B-2 % by mass (B) 7025 B-3 % by mass 100 65 Polyamide 1020J C % by mass resin (C) Acrylic- LA4285 — % by mass 100 40 based elastomer MFR(A) g/10 min — 30 — — 30 30 6 1 30 30 MFR(B) g/10 min — — 3 1 3 3 3 3 1 3 MFR(A)-MFR(B) g/10 min — — — — 27 27 3 −2 29 27 Peak temperature at 120 to ° C. — 61 160 163 160 160 160 160 163 160 170° C. in DSC measurement Heat of fusion of mJ/mg — — 15 63 10 5 10 10 41 6 peak at 120 to 170° C. in DSC measurement Heat of fusion due mJ/mg — — 15 63 10 5 10 10 41 6 to propylene-based resin (B) in resin composition Weldability PVC sheet — OK OK NG NO OK OK NG NO NG OK using high- frequency welder Weldable — NO OK NG NG OK OK OK OK NG NG sheets Heat resistance 70° C. — OK NG NG OK NG NO NO NO OK OK 100° C. — OK NO NO OK NG NO NO NO OK OK Sheet formability — D D D A D D D D A A UV absorbance — NG — — — — — — — — NO

[0176] The following are clear from Tables 1 and 2.

[0177] The resin compositions in Examples 1 to 9 have good weldability to a PVC sheet using the high-frequency welder and a high capability to weld weldable sheets together using the high-frequency welder, also have heat resistance that allows the resin compositions to withstand an atmosphere at 70° C., and have low UV absorbance.

[0178] The resin composition of the present invention uses the EVA (A) and the propylene-based resin (B) that satisfy the specific conditions. In this case, the structure of the resin composition is controlled such that the EVA (A) forms the matrix phase, so that high weldability using the high-frequency welder is obtained. Moreover, the structure is controlled such that the propylene-based resin (B) forms the domain phase, so that heat resistance can be obtained.

[0179] In particular, heat resistance was very high in Examples 3, 6, and 7.

[0180] In Example 3, the heat of fusion of the resin composition was set to be relatively high, so that the heat resistance was improved. In Examples 6 and 7, a small amount of the polyamide resin (C) was added. In this case, the amount of heat generated by the weldable sheet itself was high, so that the composition with a high heat of fusion could be melted sufficiently.

[0181] In Examples 4 and 5, although the polyamide resin (C) was added, the heat resistance at 100° C. was not satisfactory because the heat of fusion of the resin composition was lower than those in other Examples.

[0182] In Comparative Example 1, the acrylic-based elastomer alone was used. Although the weldability to PVC using the high-frequency welder was good, the acrylic-based elastomer could not be used to weld the sheets together, and the UV absorbance was high and rated NG. Therefore, this material is not suitable for welding applications using the high-frequency welder and applications with UV absorbance requirements.

[0183] In Comparative Example 2, the EVA alone was used. Although the weldability was good, the heat resistance was insufficient because no heat resistance imparting component was contained.

[0184] In Comparative Examples 3 and 4, the propylene-based resin used alone was nonpolar, and the weldability was not obtained.

[0185] In Comparative Examples 5 and 6, although the weldability was good, the heat resistance was insufficient because the heat of fusion of the resin composition was low.

[0186] In Comparative Examples 7 and 8, since MFR (A)-MFR (B) was outside the range of the present invention, the structure could not be controlled such that the EVA formed the matrix phase, so that the weldability was insufficient. Moreover, since the heat of fusion of the resin composition was low, the heat resistance was also insufficient.

[0187] In Comparative Example 9, the heat of fusion of the resin composition was excessively high. Therefore, although the heat resistance was good, the weldability was insufficient.

[0188] In Comparative Example 10, the amount of the acrylic-based elastomer used in Comparative Example 1 was reduced with the aim of improving the capability to weld the weldable sheets together and the UV absorbance. However, even when the amount added was reduced, sufficient effects were not obtained.

[0189] Although the present invention has been described in detail by way of the specific modes, it is apparent for those skilled in the art that various changes can be made without departing from the spirit and scope of the present invention.

[0190] The present application is based on Japanese Patent Application No. 2019-026725 filed on Feb. 18, 2019, the entire contents of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

[0191] According to the resin composition of the present invention, the drawbacks of PVS such as insufficient heat resistance, insufficient chemical resistance, and low shock resistance can be improved. Moreover, the resin composition can be welded to PVC using a high-frequency welder, which is a representative processing method for PVC, and can also be used to weld films or sheets together using the high-frequency welder.

[0192] Therefore, the film or multilayer body formed of the resin composition of the present invention can be suitably used for packaging materials for various food products, medical and pharmaceutical products, etc. Moreover, since the UV absorbance of the film or multilayer body formed of the resin composition of the present invention is low, the film or multilayer body can be preferably used for packaging bags for medical use such as infusion bags and tubes, bags for blood-related materials (such as blood plasma bags), and blood circuit tubes.