JP2019035072A - Resin composition for heat seal and film using the same - Google Patents

Abstract

To provide a resin composition for heat seal which has good formability and forms a weak seal of 2.9 to 9.8 N/15 mm width with a wide temperature width, and can also form a strong seal of 29.4 N/15 mm width at a practical heat seal temperature of 160°C or lower, in a method for controlling a heat seal strength on a heat seal condition, and a film using the same.SOLUTION: A resin composition for heat seal is a resin composition which contains 30-95 wt.% of component (A) of a polypropylene resin, 5-70 wt.% of component (B) of a polypropylene resin, and arbitrarily contains 0 pt.wt. or more and 100 pts.wt. or less of an elastomer (C) with respect to 100 pts.wt. of the total of the polypropylene resin (A) and the polypropylene resin (B), where a difference in a melt peak temperature between the polypropylene resin (A) and the polypropylene resin (B) is 20°C or more.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition for heat sealing and a film using the resin composition for heat sealing.

As one of the packaging containers, a multi-chamber container having a partition portion formed therein has been proposed. A multi-chamber container is a container in which a partition part is formed, and is formed by bag-making a resin film or sheet by heat sealing.
Such multi-chamber containers are used in beverages, pharmaceuticals, cosmetics, chemicals, miscellaneous goods, etc., and are used by mixing two or more components immediately before use. Especially in the medical field, prevention of denaturation by mixing chemicals, ease of preparation in clinical settings, prevention of bacterial contamination and contamination, prevention of errors during drug preparation, quick response during emergency use, pharmacists and nurses Multi-chamber containers are widely used from the viewpoint of reducing the burden on the house.

In the case of a multi-chamber container as described above, the peripheral portion needs to have sufficient heat seal strength (strong seal: approximately 29.4 N / 15 mm width or more). In addition, the resin film or sheet is difficult to peel off during production or transportation, and heat seal strength (weak seal: approximately 2.9 N to approximately 2.9N) that can be easily peeled off by hand or instrument during use (during mixing) 9.8 N / 15 mm width), and it is necessary to make these compatible.
A method for controlling these strengths only by the heat seal temperature is also known, but it is extremely difficult to control the temperature of the heat seal mold when forming the partition, the occurrence rate of defective products is high, and a large number of multi-chamber containers are used. It is an impediment to production.

  As a method for stably developing a weak seal, a method in which a polypropylene resin and a resin other than polypropylene are mixed and used is known. For example, in Japanese Patent Application Laid-Open No. 09-099037 (Patent Document 1), a medical multi-chamber container using a polymer composition comprising polypropylene and an olefin-based thermoplastic elastomer or styrene-based thermoplastic elastomer having a melting point of 140 ° C. or less based on a metallocene catalyst. Is disclosed. The technique described in Patent Document 1 is useful as a technique for developing the weak seal strength of the partition wall portion of the multi-chamber container. It can be said that it is difficult to express sufficient strong seal strength.

  JP 2010-229256 (Patent Document 2) discloses a multi-chamber container made of a resin composition in which two types of polypropylene resin and an ethylene-α-olefin copolymer component are mixed at a specific ratio. It is disclosed. In the technique described in Patent Document 2, it is possible to form a weak seal and a strong seal. However, in order to develop a strong seal, very severe sealing conditions of 4 seconds at 225 ° C. are required. There was a problem in processability.

  On the other hand, Japanese Patent Application Laid-Open No. 2003-052791 (Patent Document 3) discloses a multi-chamber container made of a polypropylene resin composition in which a heat seal part is obtained by specific two-stage polymerization. However, in the technique described in Patent Document 3, blocking between the formed heat seal layers tends to occur remarkably, and the workability is poor.

  Japanese Patent Laid-Open No. 2006-021504 (Patent Document 4) discloses that a heat-sealable sealing layer includes a propylene / α-olefin random copolymer having a crystal melting point of 135 to 145 ° C. and a crystal melting point exceeding 160 ° C. A flexible plastic film is disclosed, characterized in that it consists of a mixture with a polypropylene homopolymer. However, the technique described in Patent Document 4 has a problem that the temperature range in which weak seal strength can be formed is as narrow as 2 ° C.

  JP 2001-226499 A (Patent Document 5) discloses a propylene / α-olefin copolymer (A), and a propylene / α-olefin having a different α-olefin content from the copolymer (A). An easily peelable film comprising a mixture of a copolymer (B) and / or a propylene homopolymer (C) is disclosed. However, the technique described in Patent Document 5 requires a long time of 10 seconds in order to develop a weak seal, which is not an industrially practical method.

JP 09-099037 A JP 2010-229256 A Japanese Patent Laid-Open No. 2003-052791 JP 2006-021504 A JP 2001-226499 A

  Under such circumstances, the object of the present invention is to form a weak seal having a good moldability and a wide temperature range of 2.9 to 9.8 N / 15 mm width in a method for controlling the heat seal strength according to the heat seal conditions. In addition, another object of the present invention is to provide a heat sealing resin composition capable of forming a strong seal of 29.4 N / 15 mm width at a practical heat sealing temperature of 160 ° C. or lower and a film using the same.

  In order to solve the above problems, the present inventor has specified a polypropylene resin that is a low melting multistage polymer having different MFR and a polypropylene resin having a high melting point as propylene resins used for a sealant layer (heat seal layer). In addition, by defining the relationship between the melting peak temperature, the melting peak temperature difference and the melt flow rate in these polypropylene resins, the moldability is good and a wide weak seal temperature range is exhibited, and it is 160 ° C. or less. The present inventors have found a resin composition that can exhibit a strong seal at a practical heat seal temperature and have completed the present invention.

That is, according to 1st invention of this invention, the following polypropylene resin (A) component 30-95 weight%, the following polypropylene resin (B) component 5-70 weight%, polypropylene resin (A), and polypropylene A resin composition optionally containing 0 to 100 parts by weight of the elastomer (C) with respect to 100 parts by weight of the total resin (B), comprising a polypropylene resin (A) and a polypropylene resin (B) A resin composition for heat sealing is provided in which the difference in melting peak temperature is 20 ° C. or more.
Component (A): a multistage polymer satisfying the following requirements (A-1) and (A-2), wherein the first component of the multistage polymer is from (a-1) to (a-3) Polypropylene resin that meets the requirements.
(A-1) Melt flow rate (JIS K7210, temperature 230 ° C., 2.16 kg load) is 1 g / 10 min or more and 50 g / 10 min or less (A-2) melting peak temperature by DSC is 110 ° C. or more Less than 140 ° C.
(A-1) Melt flow rate (JIS K7210, temperature 230 ° C., 2.16 kg load) is 0.1 g / 10 min or more and 10 g / 10 min or less (a-2) melting peak temperature by DSC is 110 It must be at least ℃ and less than 140 ℃.
(A-3) The first component is 5 to 95 parts by weight with respect to 100 parts by weight of the polypropylene resin (A).
Component (B): Polypropylene resin that satisfies the following requirements (B-1) and (B-2) (B-1) Melt flow rate (230 ° C., 2.16 kg load) is 0.5 g / 10 min or more 25 g / 10 min or less.
(B-2) The melting peak temperature by DSC is 140 ° C. or higher.
According to the second invention of the present invention, in the first invention, the MFR of the second component calculated from the total MFR of the polypropylene resin (A) and the MFR of the first component is 50 g / A resin composition for heat sealing that is greater than 10 minutes and less than or equal to 10,000 g / 10 minutes is provided.
Moreover, according to the 3rd invention of this invention, the resin composition for heat seals in which the said polypropylene-type resin (A) is a metallocene-type polymer in the 1st or 2nd invention is provided.
According to a fourth aspect of the present invention, in any one of the first to third aspects, the elastomer (C) is an ethylene-α-olefin copolymer and / or a styrene-based elastomer and / or propylene- A resin composition for heat sealing, which is an α-olefin copolymer, is provided.
Moreover, according to 5th invention of this invention, it is a film which consists of 1 layer or more containing at least a heat seal layer, Comprising: A heat seal layer is a resin for heat seals in any one of 1st-4th invention. A film comprising the composition is provided.
According to a sixth aspect of the present invention, there is provided a film according to the fifth aspect, wherein the film is for a multi-chamber bag for infusion.

  According to the resin composition of the present invention, since the moldability is good, a wide weak seal temperature range is exhibited, and a strong seal can be expressed at a practical heat seal temperature of 160 ° C. or less, the seal strength is easily achieved by the seal temperature. It is industrially effective. For this reason, the resin composition of the present invention exhibits performance suitable as a sealant for a multi-chamber container, particularly a multi-chamber bag for infusion.

  Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example of the embodiments of the present invention. The description is not limited.

[Resin composition]
One embodiment of the present invention comprises a polypropylene resin (A) component of 30 to 95% by weight, a polypropylene resin (B) component of 5 to 70% by weight, a polypropylene resin (A) and a polypropylene resin (B). A resin composition that optionally contains 0 to 100 parts by weight of elastomer (C) with respect to a total of 100 parts by weight, wherein the difference in melting peak temperature between polypropylene resin (A) and polypropylene resin (B) is It is a resin composition for heat seal which is 20 ° C or more. The characteristics required for each resin component will be described below.

1. Polypropylene resin (A)
The polypropylene resin (A) is a multistage polymer, and is selected from a propylene homopolymer and a copolymer of propylene and an α-olefin having 2 to 12 carbon atoms (excluding 3 carbon atoms), preferably propylene- An ethylene copolymer or a propylene-ethylene-butene copolymer. Further, the order of polymerization may be the first component below or the second component below.

Moreover, the catalyst for producing the polypropylene resin (A) is not particularly limited, but the polypropylene resin (A) is preferably polymerized with a metallocene catalyst.
It is known that ethylene-based polymers and propylene-based polymers can control structural characteristics such as molecular weight, molecular weight distribution, and branched structure by selecting a catalyst. For example, an ethylene polymer or a propylene polymer polymerized with a metallocene catalyst may be referred to as a metallocene ethylene polymer or a metallocene propylene polymer, or a catalyst other than a metallocene catalyst. In some cases, the ethylene polymer or propylene polymer polymerized in step 1 is referred to as a nonmetallocene ethylene polymer or a nonmetallocene propylene polymer.

  The polypropylene resin (A) is a multistage polymer that satisfies the following requirements (A-1) and (A-2). The first component of the multistage polymer satisfies the requirements (a-1) to (a-3).

1-1) Requirements (A-1): Melt flow rate (230 ° C., 2.16 kg load)
The melt flow rate (230 ° C., 2.16 kg load) of the entire polypropylene resin (A) is 1.0 g / 10 min or more and 50 g / 10 min or less, preferably 1 to 30 g / 10 min, more preferably 1 to 20 g / 10 min, particularly preferably 1 to 15 g / 10 min. When the melt flow rate is 1.0 g / 10 min or more, the load at the time of forming the heat seal film does not increase, and the laminate itself can be easily formed. If it is 50 g / 10 minutes or less, the molding stability at the time of molding a film for heat sealing is good.

1-2) Requirement (A-2): Melting peak temperature by differential scanning calorimetry (DSC) The melting peak temperature (by DSC) of the polypropylene resin (A) is 110 ° C. or higher and lower than 140 ° C., preferably 115. It is 120 degreeC or more and less than 140 degreeC, More preferably, it is 120 degreeC or more and less than 140 degreeC, Most preferably, it is 120 degreeC or more and 135 degreeC or less. Note that the melting peak temperature may be referred to as the melting point. If the melting peak temperature is 110 ° C. or higher, the film for heat sealing obtained by combining with the polypropylene resin (B) is heat-sealed between the films during sterilization at a high temperature of, for example, 121 ° C. for 30 minutes. Unintentional fusion of unexposed parts is unlikely to occur. Moreover, if melting peak temperature is less than 140 degreeC, it will be easy to take the heat seal temperature range from which a heat seal intensity | strength will be 2.9-9.8N / 15mm width by combining with a polypropylene resin (B).

1-3) Requirement (a-1): Melt flow rate of the first component (230 ° C., 2.16 kg load)
The melt flow rate (230 ° C., 2.16 kg load) of the first component of the polypropylene resin (A) is 0.1 g / 10 min or more and 10 g / 10 min or less, preferably 0.5 g / 10 min. It is 10 g / 10 min or less, more preferably 1 g / 10 min or more and 10 g / 10 min or less. When the melt flow rate of the first component is 0.1 g / 10 min or more, the load at the time of forming the heat-sealing film does not increase, and the laminate itself can be formed easily. If it is 10 g / 10 minutes or less, the molding stability at the time of molding the film for heat sealing is good.

1-4) Requirement (a-2): Melting peak temperature by differential scanning calorimetry (DSC) of the first component The melting peak temperature (by DSC) of the first component of the polypropylene resin (A) is 110 ° C. It is more than 140 degreeC, Preferably it is 115 degreeC or more and less than 140 degreeC, More preferably, it is 120 degreeC or more and less than 140 degreeC, Most preferably, it is 120 degreeC or more and 135 degreeC or less. If the melting peak temperature is 110 ° C. or higher, the film for heat sealing obtained by combining with the polypropylene resin (B) is heat-sealed between the films during sterilization at a high temperature of, for example, 121 ° C. for 30 minutes. Unintentional fusion of unexposed parts is unlikely to occur. Moreover, if melting peak temperature is less than 140 degreeC, it will be easy to take the heat seal temperature range from which a heat seal intensity | strength will be 2.9-9.8N / 15mm width by combining with a polypropylene resin (B).

1-5) Requirement (a-3): Ratio of first component to 100 parts by weight of polypropylene resin (A) The ratio of the first component to 100 parts by weight of polypropylene resin (A) is 5 parts by weight or more and 95 parts by weight. Part or less, preferably 20 parts by weight or more and 90 parts by weight or less, more preferably 30 parts by weight or more and 90 parts by weight or less. When the ratio of the first component to 100 parts by weight of the polypropylene resin (A) is 5 parts by weight or more, the molding stability at the time of forming the heat seal film is good, and the first component to 100 parts by weight of the polypropylene resin (A). When the ratio of the component is 95 parts by weight or less, it is easy to take a wide heat seal temperature range in which the heat seal strength is 2.9 to 9.8 N / 15 mm width by combining with the polypropylene resin (B).

2. Polypropylene resin (B)
The polypropylene resin (B) is composed of one type or two or more types of propylene polymers, and when composed of two or more types of components, the following properties (b-1) to (b) -2) may be satisfied.

  The polypropylene resin (B) is selected from one or more propylene homopolymers, and a copolymer of propylene and an α-olefin having 2 to 12 carbon atoms (excluding 3 carbon atoms), preferably propylene alone. It is a polymer.

  The polypropylene resin (B) can be appropriately selected from commercially available propylene homopolymers and propylene-α-olefin copolymers. Specifically, the product name “Novatech PP” manufactured by Nippon Polypro Co., Ltd. and the product name “Wintech” can be mentioned.

2-1) Requirements (B-1): Melt flow rate (230 ° C., 2.16 kg load)
The melt flow rate (230 ° C., 2.16 kg load) of the polypropylene resin (B) is 0.5 g / 10 min or more and 25 g / 10 min or less, preferably 0.5 to 15 g / 10 min, more preferably 0.5 to 10 g / 10 min. When the melt flow rate is 0.5 g / 10 min or more, when combined with the polypropylene resin (A), poor appearance of a film such as fish eye is hardly caused. If it is 25 g / 10 min or less, the heat seal strength of the heat seal film obtained by combining with the polypropylene resin (A) is wide from 2.9 to 9.8 N / 15 mm. easy.

2-2) Requirement (B-2): Melting peak temperature by differential scanning calorimetry (DSC) The melting peak temperature (by DSC) of the polypropylene resin (B) is 140 ° C or higher, preferably 150 ° C or higher. More preferably, it is 155 degreeC or more, Most preferably, it is 160 degreeC or more. If the melting peak temperature is 140 ° C. or higher, the heat seal temperature width at which the heat seal strength of the heat seal film obtained by combining with the polypropylene resin (A) is 2.9 to 9.8 N / 15 mm width is set. Wide and easy to take. The upper limit of the melting peak temperature of the polypropylene resin (B) is not particularly limited, but is preferably 170 ° C. or lower, for example.

  In the present invention, from the viewpoint of ensuring a wide seal temperature range, the difference between the melting peak temperature of the polypropylene resin (A) and the melting peak temperature of the polypropylene resin (B) is 20 ° C. or more, preferably 25 ° C. That's it.

  Although it is not well understood why the heat seal strength of the film for heat sealing made of the resin composition of the present invention is easily 2.9 to 9.8 N / 15 mm wide, it is not well understood, but polypropylene resin If (A) is a multistage polymer and the difference in melting peak temperature from the polypropylene resin (B) is 20 ° C. or more, the microscopic mixed state of the polypropylene resin (A) and the polypropylene resin (B) is It is considered that the polypropylene-based resin (B) is optimized and acts to suppress an increase in seal strength, and exhibits a wide weak seal temperature range.

The resin composition of the present invention contains 30 to 95% by weight of the polypropylene resin (A) and 5 to 70% by weight of the polypropylene resin (B).
The content of the polypropylene resin (A) is 30 to 95% by weight, preferably 40 to 95% by weight, more preferably 45 to 90% by weight, and still more preferably 50 to 85% by weight. The content of the polypropylene resin (B) is 5 to 70% by weight, preferably 5 to 60% by weight, more preferably 10 to 55% by weight, and still more preferably 15 to 50% by weight.
When the content of the polypropylene resin (A) and the polypropylene resin (B) is in the above range, the heat seal temperature at which the heat seal strength of the obtained heat seal film is 2.9 to 9.8 N / 15 mm width is obtained. Easy to take a wide width. Moreover, it can prevent that the temperature from which heat seal intensity | strength becomes 29.4N / 15mm width or more becomes high too much. For this reason, a strong seal can be formed at a practical heat seal temperature of 160 ° C. or less.

  In the polypropylene resin (A), the MFR of the second component calculated from the quantitative ratio between the MFR of the entire polypropylene resin (A) and the MFR of the first component is greater than 50 g / 10 minutes and 10,000 g / 10 min or less, preferably 75 g / 10 min or more and 5000 g / 10 min or less, more preferably 500 g / 10 min or more and 1000 g / 10 min or less. If the melt flow rate of the second component is larger than 50 g / 10 min, the weak seal forming temperature range tends to be wide when blended with the polypropylene resin (B). Moreover, if it is 10000 g / 10min or less, the shaping | molding stability at the time of the film formation for heat seals will be favorable.

About MFR calculation method In many cases, the MFR of the multistage polymer can only measure the MFR of the entire multistage polymer and the MFR of either the first component or the second component. As an unknown MFR calculation method of the first component or the second component, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2001-72730 can be cited, and according to Equation 2 of the publication, the first component or the second component Even if the MFR of any one of the components is unknown, if the MFR of the entire multistage polymer and the MFR of either the first component or the second component and the weight ratio of the first component to the second component are known, the unknown MFR Can be estimated.

3. Elastomer (C)
Moreover, the resin composition of this invention contains the elastomer (C) 0 weight part or more and 100 weight part or less arbitrarily with respect to a total of 100 weight part of a polypropylene resin (A) and a polypropylene resin (B).

  The elastomer (C) is contained when the film made of the resin composition for heat sealing of the present invention requires impact resistance or when further adjustment of heat sealing characteristics is required.

The content of the elastomer (C) is 0 part by weight or more and 100 parts by weight or less, preferably 0 part by weight or more and 70 parts by weight with respect to 100 parts by weight of the total of the polypropylene resin (A) and the polypropylene resin (B). Hereinafter, more preferably 0 part by weight or more and 60 parts by weight or less, further preferably 10 parts by weight or more and 60 parts by weight or less, and particularly preferably 10 parts by weight or more and 50 parts by weight or less.
If the content of the elastomer (C) is 100 parts by weight or less, the obtained heat-sealing film is intended to be a part where the film is not heat-sealed during sterilization at a high temperature of, for example, 121 ° C. for 30 minutes. Unnecessary fusion is unlikely to occur, and when heat-sealing at a high temperature, it is easy to achieve a heat-sealing strength of 29.4 N / 15 mm width or more.

  The elastomer (C) is not particularly limited as long as it can impart impact resistance, but an ethylene-α-olefin copolymer, a styrene elastomer, a propylene-α-olefin copolymer, or a mixture thereof is preferable.

The ethylene-α-olefin copolymer is a copolymer obtained by copolymerizing ethylene and preferably an α-olefin having 3 to 20 carbon atoms, and the α-olefin is a copolymer having 3 to 20 carbon atoms. Preferred examples thereof include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-heptene.
Examples of commercially available products include “Polymer” series manufactured by Nippon Polyethylene Co., Ltd., “Tuffmer A” series and “Tuffmer MY” series manufactured by Mitsui Chemicals, and “Affinity” series manufactured by Dow, Engage "series, trade name" EXACT "series manufactured by ExxonMobil, and the like.
The density of the ethylene -α- olefin copolymer is preferably 0.86~0.91g / cm ^3, more preferably 0.87~0.90g / cm ^3.
The melt index (190 ° C., 2.16 kg load) of the ethylene-α-olefin copolymer is preferably 0.5 to 10 g / 10 min.
The propylene-α-olefin copolymer is a copolymer obtained by copolymerizing propylene and preferably an α-olefin having 2 to 20 carbon atoms (excluding 3), and the α-olefin is carbon. Preferred examples are those having a number of 2 to 20 (excluding 3), such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-heptene.
As an example of a commercial item, the brand name "Vistamaxx" series by ExxonMobil, etc. are mentioned.
The styrene-based elastomer can be appropriately selected from commercially available ones. For example, as a hydrogenated product of a styrene-butadiene block copolymer, “Clayton G” is available from Kraton Polymer Japan Co., Ltd. Styrene-vinylated polyisoprene block under the product name, “Tough Tech” from Asahi Kasei Chemicals, Inc. and “Septon” from Kuraray Co., Ltd. as a hydrogenated product of styrene-isoprene block copolymer. As a hydrogenated product of the copolymer, Kuraray Co., Ltd. sells it under the product name “Hibler”, and as a hydrogenated product of the styrene-butadiene random copolymer, it is sold under the product name “Dynalon” by JSR Corporation. You may select and use suitably from these goods groups.

4). Other Components Various other components such as other resins or additives can be added to the resin composition for heat sealing of the present invention as long as the object of the present invention is not impaired.
In the heat sealing resin composition of the present invention, an additive such as an antioxidant that can be added to the polypropylene resin can be appropriately blended as long as the effects of the present invention are not hindered.
Specifically, 2,6-di-t-butyl-p-cresol (BHT), tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane (BASF Japan) (Trade name “IRGANOX 1010”) and n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate (trade name “IRGANOX 1076” manufactured by BASF Japan) Stabilizers, phosphite stabilizers typified by bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite and tris (2,4-di-t-butylphenyl) phosphite, olein Lubricants represented by higher fatty acid amides such as acid amides and erucic acid amides, higher fatty acid esters and silicone oils, Antistatic agent represented by glycerin ester, sorbitan acid ester, polyethylene glycol ester, etc. of fatty acid having 8 to 22 elementary atoms, sorbitol nucleating agent (for example, trade name “Gelol MD” manufactured by Shin Nippon Rika Co., Ltd.), aroma Group phosphoric acid esters (for example, trade names “Adeka Stub NA-21” and “Adeka Stub NA-11” and “Adeka Stub NA-11” manufactured by ADEKA), a product name “Millad” manufactured by Milliken, and a product name “Hyperform” manufactured by Milliken Company name “NJ Star NU-100”, nucleating agent represented by talc, high-density polyethylene, etc., anti-blocking agent represented by silica, calcium carbonate, talc, organic peroxide, etc. Molecular weight modifiers, crosslinking aids, higher fatty acid metal salts such as calcium stearate, Neutralizers such as hydrotalcite, light stabilizers, UV absorbers, metal deactivators, peroxides, fillers, antibacterial and antifungal agents, antibacterial agents, antibacterial agents, fluorescent whitening agents, antibacterial agents A clouding agent, a flame retardant, a colorant, a pigment, a natural oil, a synthetic oil, a wax, or an organic or inorganic flame retardant may be added depending on the application, and the amount is appropriately determined.

[Method for Producing Resin Composition]
The resin composition for heat sealing of the present invention comprises the above-mentioned polypropylene resin (A), the polypropylene resin (B) and, if necessary, an elastomer (C), additives and / or other resins, a Henschel mixer (product Name), V blender, ribbon blender, tumbler blender, etc., and then kneading with a kneader such as a single screw extruder, multi-screw extruder, kneader, Banbury mixer, etc. As another form, the polypropylene resin (A), the polypropylene resin (B) and, if necessary, the elastomer (C) are individually added to the additive and / or other resins as Henschel mixers (trade name) ), V blender, ribbon blender, tumbler blender, etc., then kneaded and pelletized with a kneader such as a single screw extruder, multi screw extruder, kneader, Banbury mixer, etc. Henschel mixer (trade name), V blender It can also be obtained as a pellet mixture mixed with a ribbon blender, a tumbler blender or the like. When an elastomer or other additive is used as an optional component, it can be added when obtaining the pellet mixture. Moreover, what was made into the mixture blended with the Henschel mixer (brand name), V blender, ribbon blender, tumbler blender, etc. can also be used as a pellet mixture as it is.

[the film]
The heat-seal resin composition of the present invention is suitably used for a heat-seal film containing one or more of the resin compositions as a heat-seal layer, particularly a heat-seal film that achieves both a low heat-seal strength and a high heat-seal strength. I can do it.
The film of the present invention is a film composed of one or more layers including at least a heat seal layer, and the heat seal layer is composed of the above-described heat sealing resin composition of the present invention.
The film may be a single layer or a multilayer, but is preferably a multilayer film from the viewpoint of operability during heat sealing.
The film may be an unstretched film or a film stretched in a uniaxial direction or more. In addition, as a stretched film, the film etc. which were extended | stretched sequentially or simultaneously in the flow direction of a film and / or a direction orthogonal to a flow are mentioned. Although there is no restriction | limiting in particular in the thickness of a film, In the case of a single layer film, the thing of about 10-500 micrometers is used suitably as a sealant. In the case of a multilayer film, the thickness of the entire multilayer film is about 10 to 500 μm, and the heat seal layer of the present invention is preferably about 5 to 100 μm, preferably 10 to 60 μm, and more preferably about 20 to 50 μm.
As the multilayer film, a heat-seal layer comprising the heat-seal resin composition of the present invention and a two-layer film having an outer layer adjacent thereto, a heat-seal layer comprising the heat-seal resin composition of the present invention, and A three-layer film having an adjacent intermediate layer and an outer layer adjacent to the intermediate layer, a heat seal layer made of the resin composition for heat sealing of the present invention, an adhesive layer adjacent thereto, and a barrier layer adjacent to the adhesive layer Further, a five-layer film having an adhesive layer adjacent to the barrier layer and an outer layer adjacent to the adhesive layer can be used, but not limited to these, as long as the heat sealing resin composition of the present invention is used as a heat seal layer. It can be set as the following.
Examples of the method for producing a multilayer film include a coextrusion method, an extrusion lamination method, a dry lamination method, and the like, but the coextrusion method is preferable from the viewpoint of economy.
Although the manufacturing method of the film of this invention is not specifically limited, It can manufacture by a well-known method using the said resin composition. For example, it is produced by a known technique such as extrusion using a T die or a circular die.
Among these, a water-cooled inflation molding method using a circular die is preferable from the viewpoint of transparency.
Since the film of the present invention includes the heat seal layer made of the above-described heat seal resin composition of the present invention, it can form a weak seal strength of 2.9 to 9.8 N / 15 mm width over a wide temperature range, and It can be formed without making extremely strong conditions such as 29.4 N / 15 mm width, and unintentional fusion between films is unlikely to occur in heat treatment processes such as sterilization and sterilization. It is suitable for a heat treatment packaging bag, particularly a multi-chamber bag for infusion.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto without departing from the gist thereof. In addition, the measuring method of the various physical-property values in an Example, and the used material are as follows.

1. Measurement method (1) MFR (unit: g / 10 minutes): Measured at 230 ° C. under a load of 2.16 kg according to JIS K-7210. Further, in the polypropylene resin (A), the MFR of the second component calculated from the MFR of the entire polypropylene resin (A) and the MFR of the first component is expressed by the equation 2 disclosed in JP-A-2001-72730. According to the following calculation formula.
logC = logA + blogB
A: MFR of the first component, a: Weight ratio of the first component in the polypropylene resin (A) B: MFR of the second component, b: Second of the polypropylene resin (A) Component weight ratio C: MFR of the entire polypropylene resin (A)
However, a + b = 1.
(2) Melting peak temperature: Using a differential scanning calorimeter (TA Instruments, Q2000 type), a sample amount of 5.0 mg was taken, held at 200 ° C. for 5 minutes, and then cooled down to 40 ° C. at 10 ° C./min. And then the melting peak temperature was measured when it was melted at a heating rate of 10 ° C./min.
(3) Heat seal strength (unit: N / 15 mm width): Using a heat seal bar of 5 mm × 200 mm, the obtained film is 5 in the range of 110 ° C. to 160 ° C. so that the heat seal layers are heat sealed. Sealing was performed so as to be perpendicular to the direction (MD) of melt extrusion under heat sealing conditions of a pressure of 0.34 MPa and a time of 5 seconds in increments of ° C. Next, the sample was cut out so that the heat seal portion had a width of 15 mm, and separated by using a tensile tester at a pulling speed of 500 mm / min, and the heat seal strength was determined. Plot the relationship between the heat seal temperature and the maximum heat seal strength, obtain the slope from the curve obtained, and determine the weak seal start temperature (temperature at which the heat seal strength reaches 2.9 N / 15 mm width), the weak seal end temperature (heat The temperature at which the seal strength reaches 9.8 N / 15 mm width) and the strong seal start temperature (the temperature at which the heat seal strength reaches 29.4 N / 15 mm width) were determined. When the heat seal strength is 2.9 to 9.8 N / 15 mm width, the resin film or sheet is difficult to peel off at the time of manufacture or transportation, and the partition portion inside the container is difficult to peel off during use (during mixing). If it is easily peeled off with a hand or an instrument and is 29.4 N / 15 mm width or more, it can be said that the heat seal strength is sufficient. If the weak seal temperature range is 10 ° C. or higher, it can be said that the weak seal strength can be easily formed.

2. Material PP1 (Propylene / α-olefin random copolymer polymerized with metallocene catalyst): The multistage polymer obtained in the following <Production example of PP1> was used (melting peak temperature: 122 ° C., MFR: 5. 3 g / 10 min).
PP2 (Propylene / α-olefin random copolymer polymerized with metallocene catalyst): The multistage polymer obtained in the following <Production Example of PP2> was used (melting peak temperature: 121 ° C., MFR: 5.7 g / 10 minutes).
PP3 (Propylene / α-olefin random copolymer polymerized with metallocene catalyst): trade name Wintech WFX4M manufactured by Nippon Polypro Co., Ltd. (melting peak temperature: 125 ° C., MFR: 7 g / 10 min, not a multistage polymer) .
PP4 (Propylene / α-olefin random copolymer polymerized with metallocene catalyst): Brand name Wintech WFX6 manufactured by Nippon Polypro Co., Ltd. (melting peak temperature: 125 ° C., MFR: 2 g / 10 min, not a multistage polymer) .
PP5 (propylene homopolymer polymerized with Ziegler catalyst): Nippon Polypro Co., Ltd. trade name Novatec PP FY4 (melting peak temperature: 160 ° C., MFR: 5 g / 10 min).
PP6 (propylene homopolymer polymerized by Ziegler catalyst): Nippon Polypro Co., Ltd. trade name Novatec PP FA3KM (melting peak temperature: 161 ° C., MFR: 10 g / 10 min).
PP7 (propylene homopolymer polymerized by Ziegler catalyst): Nippon Polypro Co., Ltd. trade name Novatec PP FY6 (melting peak temperature: 162 ° C., MFR: 2.4 g / 10 min).

<Production example of PP1>
(I) Preparation of prepolymerized catalyst (chemical treatment of silicate)
To a 10-liter glass separable flask with a stirring blade, 3.75 liters of distilled water was added slowly followed by 2.5 kg of concentrated sulfuric acid (96%). At 50 ° C., 1 kg of montmorillonite (trade name “Benclay SL” manufactured by Mizusawa Chemical Co., Ltd .; average particle size = 25 μm, particle size distribution = 10-60 μm) was dispersed, heated to 90 ° C., and the temperature was maintained for 6.5 hours. Maintained.
After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry it, and then filtered. This washing operation was performed until the pH of the washing liquid (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.
(Drying silicate)
The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical inner diameter 50mm Heating zone 550mm (electric furnace)
Number of revolutions with lifting blade: 2 rpm Tilt angle: 20/520
Silicate supply rate: 2.5 g / min Gas flow rate: Nitrogen 96 liters / hour Countercurrent drying temperature: 200 ° C. (powder temperature)
(Preparation of catalyst)
An autoclave with an internal volume of 16 liters equipped with a stirring and temperature control device was thoroughly replaced with nitrogen. 200 g of dry silicate was introduced, 1160 ml of mixed heptane and 840 ml of a heptane solution of triethylaluminum (0.60 M) were added, and the mixture was stirred at room temperature. After 1 hour, the mixture was washed with mixed heptane, and the silicate slurry was adjusted to 2,000 ml. Next, 9.6 ml of a heptane solution of triisobutylaluminum (0.71 M) was added to the silicate slurry prepared above, and the mixture was reacted at 25 ° C. for 1 hour. In parallel, 177 ml (3 mmol) of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium and 870 ml of mixed heptanes were added to Add 33.1 ml of isobutylaluminum heptane solution (0.71M) and react for 1 hour at room temperature. Add to silicate slurry, stir for 1 hour, add mixed heptane to adjust to 5,000 ml. did.
(Prepolymerization / washing)
Subsequently, the temperature in the tank was raised to 40 ° C., and when the temperature was stabilized, propylene was supplied at a rate of 100 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the remaining monomer was purged, the stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then the supernatant was decanted to 2,400 ml. Subsequently, 9.5 ml of a heptane solution of triisobutylaluminum (0.71 M) and 5,600 ml of mixed heptane were further added, stirred at 40 ° C. for 30 minutes, allowed to stand for 10 minutes, and then 5,600 ml of the supernatant was removed. This operation was further repeated 3 times. When the component analysis of the final supernatant was conducted, the concentration of the organoaluminum component was 1.23 mM, the Zr concentration was 8.6 × 10 ⁻⁶ g / L, and the Zr abundance (weight) in the supernatant relative to the charged amount Ratio) was 0.018% by weight. Subsequently, 170 ml of a heptane solution of triisobutylaluminum (0.71 M) was added, followed by drying under reduced pressure at 45 ° C.
By this operation, a prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of catalyst was obtained.
Using this prepolymerized catalyst, a propylene-based resin composition was produced according to the following procedure.
(Ii) First polymerization step A horizontal reactor (L / D = 4.3, internal volume 100 liters) having a stirring blade was sufficiently dried, and the inside was sufficiently replaced with nitrogen gas. While stirring at a rotational speed of 33 rpm in the presence of a polypropylene powder bed, 0.71 g / hr of the prepolymerized catalyst prepared by the above method (as the amount of solid catalyst excluding the prepolymerized powder) in the upstream part of the reactor, Triisobutylaluminum was continuously fed at 30 mmol / hr. As for the temperature, the upstream side of the reactor equally divided was 53 ° C., the downstream side was 54 ° C., the pressure was maintained at 2.1 MPaG, the ethylene / propylene molar ratio in the gas phase portion in the reactor was 0.14, and the hydrogen concentration was The monomer mixed gas was continuously passed through the reactor so as to be 70 molppm, and gas phase polymerization was performed. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, the amount of polymer extracted when the steady state was reached was 7.6 kg / hr.
When the propylene-ethylene random copolymer obtained in the first polymerization step was analyzed, the MFR was 1.5 g / 10 minutes and the ethylene content was 3.3 wt%.
(Iii) Second polymerization step The propylene-ethylene copolymer extracted from the first polymerization step was continuously supplied to a horizontal reactor (L / D = 4.3, internal volume 100 liters) having a stirring blade. While stirring at a rotation speed of 25 rpm, the temperature of the reactor is maintained at 65 ° C., the pressure is maintained at 1.9 MPaG, the ethylene / propylene molar ratio of the gas phase in the reactor is 0.13, and the hydrogen concentration is 0.63 mol%. As described above, the monomer mixed gas was continuously passed through the reactor to perform gas phase polymerization. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, oxygen was supplied as an activity inhibitor so that the amount of polymer extracted was 10.0 kg / hr, and the polymerization reaction amount in the second polymerization step was controlled. The activity was 14 kg / g-catalyst.
To the powdery PP1 obtained, 1000 ppm by weight of Irganox 1010 and 1000 ppm by weight of Irgafos 1010 as antioxidants were added, mixed with a Henschel mixer, and then adjusted to 200 ° C. with a Φ30 mm single screw granulator. To obtain pellet PP1.
Moreover, the ratio of the 1st component calculated from the following formula was 76 weight%, and MFR of the 2nd component calculated from a MFR calculation formula was 280 g / 10min.
First component ratio = first polymerization step extraction amount / second polymerization step extraction amount

<Production example of PP2>
(I) Preparation of prepolymerized catalyst (chemical treatment of silicate)
To a 10-liter glass separable flask with a stirring blade, 3.75 liters of distilled water was added slowly followed by 2.5 kg of concentrated sulfuric acid (96%). At 50 ° C., 1 kg of montmorillonite (trade name “Benclay SL” manufactured by Mizusawa Chemical Co., Ltd .; average particle size = 25 μm, particle size distribution = 10-60 μm) was dispersed, heated to 90 ° C., and the temperature was maintained for 6.5 hours. Maintained.
After cooling to 50 ° C., the slurry was filtered under reduced pressure to recover the cake. 7 liters of distilled water was added to this cake to reslurry it, and then filtered. This washing operation was performed until the pH of the washing liquid (filtrate) exceeded 3.5. The collected cake was dried at 110 ° C. overnight under a nitrogen atmosphere. The weight after drying was 707 g.
(Drying silicate)
The silicate previously chemically treated was dried with a kiln dryer. Specifications and drying conditions are as follows.
Rotating cylinder: Cylindrical inner diameter 50mm Heating zone 550mm (electric furnace)
Number of revolutions with lifting blade: 2 rpm Tilt angle: 20/520
Silicate supply rate: 2.5 g / min Gas flow rate: Nitrogen 96 liters / hour Countercurrent drying temperature: 200 ° C. (powder temperature)
(Preparation of catalyst)
An autoclave with an internal volume of 16 liters equipped with a stirring and temperature control device was thoroughly replaced with nitrogen. 200 g of dry silicate was introduced, 1160 ml of mixed heptane and 840 ml of a heptane solution of triethylaluminum (0.60 M) were added, and the mixture was stirred at room temperature. After 1 hour, the mixture was washed with mixed heptane, and the silicate slurry was adjusted to 2,000 ml. Next, 9.6 ml of a heptane solution of triisobutylaluminum (0.71 M) was added to the silicate slurry prepared above, and the mixture was reacted at 25 ° C. for 1 hour. In parallel, 177 ml (3 mmol) of (r) -dichloro [1,1′-dimethylsilylenebis {2-methyl-4- (4-chlorophenyl) -4H-azulenyl}] zirconium and 870 ml of mixed heptanes were added to Add 33.1 ml of isobutylaluminum heptane solution (0.71M) and react for 1 hour at room temperature. Add to silicate slurry, stir for 1 hour, add mixed heptane to adjust to 5,000 ml. did.
(Prepolymerization / washing)
Subsequently, the temperature in the tank was raised to 40 ° C., and when the temperature was stabilized, propylene was supplied at a rate of 100 g / hour to maintain the temperature. After 4 hours, the supply of propylene was stopped and maintained for another 2 hours.
After completion of the prepolymerization, the remaining monomer was purged, the stirring was stopped and the mixture was allowed to stand for about 10 minutes, and then the supernatant was decanted to 2,400 ml. Subsequently, 9.5 ml of a heptane solution of triisobutylaluminum (0.71 M) and 5,600 ml of mixed heptane were further added, stirred at 40 ° C. for 30 minutes, allowed to stand for 10 minutes, and then 5,600 ml of the supernatant was removed. This operation was further repeated 3 times. When the component analysis of the final supernatant was conducted, the concentration of the organoaluminum component was 1.23 mM, the Zr concentration was 8.6 × 10 ⁻⁶ g / L, and the Zr abundance (weight) in the supernatant relative to the charged amount Ratio) was 0.018% by weight. Subsequently, 170 ml of a heptane solution of triisobutylaluminum (0.71 M) was added, followed by drying under reduced pressure at 45 ° C.
By this operation, a prepolymerized catalyst containing 2.0 g of polypropylene per 1 g of catalyst was obtained.
Using this prepolymerized catalyst, a propylene-based resin composition was produced according to the following procedure.
(Ii) First polymerization step A horizontal reactor (L / D = 4.3, internal volume 100 liters) having a stirring blade was sufficiently dried, and the inside was sufficiently replaced with nitrogen gas. While stirring at a rotational speed of 33 rpm in the presence of a polypropylene powder bed, 0.71 g / hr of the prepolymerized catalyst prepared by the above method (as the amount of solid catalyst excluding the prepolymerized powder) in the upstream part of the reactor, Triisobutylaluminum was continuously fed at 30 mmol / hr. As for the temperature, the upstream side of the reactor equally divided was 53 ° C., the downstream side was 54 ° C., the pressure was maintained at 2.1 MPaG, the ethylene / propylene molar ratio in the gas phase portion in the reactor was 0.14, and the hydrogen concentration was The monomer mixed gas was continuously passed through the reactor so as to be 120 molppm, and gas phase polymerization was performed. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, the amount of the polymer extracted when the steady state was reached was 8.3 kg / hr.
When the propylene-ethylene random copolymer obtained in the first polymerization step was analyzed, the MFR was 2.1 g / 10 minutes and the ethylene content was 3.2 wt%.
(Iii) Second polymerization step The propylene-ethylene copolymer extracted from the first polymerization step was continuously supplied to a horizontal reactor (L / D = 4.3, internal volume 100 liters) having a stirring blade. While stirring at a rotational speed of 25 rpm, the temperature of the reactor is maintained at 65 ° C., the pressure is maintained at 1.9 MPaG, the ethylene / propylene molar ratio in the gas phase in the reactor is 0.12, and the hydrogen concentration is 0.32 mol%. As described above, the monomer mixed gas was continuously passed through the reactor to perform gas phase polymerization. The polymer powder produced by the reaction was continuously extracted from the downstream portion of the reactor so that the amount of the powder bed in the reactor was constant. At this time, oxygen was supplied as an activity inhibitor so that the amount of polymer extracted was 10.2 kg / hr, and the amount of polymerization reaction in the second polymerization step was controlled. The activity was 22 kg / g-catalyst.
To the powdery PP2 obtained, 1000 ppm by weight of Irganox 1010 and 1000 ppm by weight of Irgafos 1010 were added as antioxidants, mixed with a Henschel mixer, and then adjusted to 200 ° C. with a Φ30 mm single screw granulator. To obtain pellets of PP2.
Moreover, the ratio of the 1st component calculated from the following formula was 81 weight%, and MFR of the 2nd component calculated from a MFR calculation formula was 400 g / 10min.
First component ratio = first polymerization step extraction amount / second polymerization step extraction amount

Example 1
As a resin for the intermediate layer of a three-type three-layer water-cooled inflation molding machine with a die diameter of φ50 mm, PP7 is used as an intermediate layer extruder of φ30 mm, PP6 is used as an extruder for a surface layer of φ18 mm on the outside of the tubular film, Among them, PP1 and PP5 were mixed at a ratio of 85% to 15% by weight, and the contents were mixed by shaking the bag up and down and left and right by hand and the inside of the tubular film having a diameter of 18 mm. It is put into a heat seal layer extruder, melt extruded from a cylindrical die at an extrusion temperature of 200 ° C., cooled and solidified with water adjusted to 10 ° C., and a film having a thickness of 200 μm and a width of 92 mm is obtained at a speed of 3 m / min. It was manufactured so that the thickness ratio of outer layer (surface layer): intermediate layer: inner layer (heat seal layer) was 1: 8: 1. Table 1 shows the evaluation results of the film.

(Example 2)
In the resin used for the heat seal layer of Example 1, the same operation as in Example 1 was performed except that PP1 was changed to PP2 and the weight ratio of PP2 and PP5 was changed to 55% to 45% to obtain a film. It was. The evaluation results of the obtained film are shown in Table 1.

(Comparative Example 1)
In the resin used for the heat seal layer of Example 1, the same operation as in Example 1 was performed except that PP1 was replaced with PP3 to obtain a film. The evaluation results of the obtained film are shown in Table 1. Compared to the examples, the temperature range at which a heat seal strength of 2.9 to 9.8 N / 15 mm width can be formed is narrow, and it is difficult to form a weak seal.

(Comparative Example 2)
In the resin used for the heat seal layer of Example 1, the same operation as in Example 1 was performed except that PP1 was replaced with PP4 to obtain a film. The evaluation results of the obtained film are shown in Table 1. Compared to the examples, the temperature range at which a heat seal strength of 2.9 to 9.8 N / 15 mm width can be formed is narrow, and it is difficult to form a weak seal.

(Comparative Example 3)
The resin used for the heat seal layer of Example 1 was subjected to the same operation as Example 1 except that only PP1 was used, and a film was obtained. The evaluation results of the obtained film are shown in Table 1. Compared to the examples, the temperature range at which a heat seal strength of 2.9 to 9.8 N / 15 mm width can be formed is narrow, and it is difficult to form a weak seal.

(Comparative Example 4)
The resin used for the heat seal layer of Example 1 was subjected to the same operation as Example 1 except that only PP3 was used to obtain a film. The evaluation results of the obtained film are shown in Table 1. Compared to the examples, the temperature range at which a heat seal strength of 2.9 to 9.8 N / 15 mm width can be formed is narrow, and it is difficult to form a weak seal.

(Comparative Example 5)
The resin used for the heat seal layer of Example 1 was subjected to the same operation as Example 1 except that only PP4 was used to obtain a film. The evaluation results of the obtained film are shown in Table 1. Compared to the examples, the temperature range at which a heat seal strength of 2.9 to 9.8 N / 15 mm width can be formed is narrow, and it is difficult to form a weak seal.

Claims (6)

30 to 95% by weight of the following polypropylene resin (A) component, 5 to 70% by weight of the following polypropylene resin (B) component, and 100 parts by weight in total of the polypropylene resin (A) and the polypropylene resin (B), A heat composition optionally containing 0 to 100 parts by weight of elastomer (C), wherein the difference in melting peak temperature between polypropylene resin (A) and polypropylene resin (B) is 20 ° C. or more Resin composition.
Component (A): a multistage polymer satisfying the following requirements (A-1) and (A-2), wherein the first component of the multistage polymer is from (a-1) to (a-3) Polypropylene resin that meets the requirements.
(A-1) Melt flow rate (JIS K7210, temperature 230 ° C., 2.16 kg load) is 1 g / 10 min or more and 50 g / 10 min or less (A-2) melting peak temperature by DSC is 110 ° C. or more Less than 140 ° C.
(A-1) Melt flow rate (JIS K7210, temperature 230 ° C., 2.16 kg load) is 0.1 g / 10 min or more and 10 g / 10 min or less (a-2) melting peak temperature by DSC is 110 It must be at least ℃ and less than 140 ℃.
(A-3) The first component is 5 to 95 parts by weight with respect to 100 parts by weight of the polypropylene resin (A).
Component (B): Polypropylene resin that satisfies the following requirements (B-1) and (B-2) (B1) Melt flow rate (230 ° C., 2.16 kg load) is 0.5 g / 10 min or more, 25 g / 10 minutes or less.
(B2) The melting peak temperature by DSC is 140 ° C. or higher.   In the polypropylene resin (A), the MFR of the second component calculated from the MFR of the entire polypropylene resin (A) and the MFR of the first component is greater than 50 g / 10 minutes and 10000 g / 10 minutes or less. The resin composition for heat sealing according to claim 1.   The resin composition for heat sealing according to claim 1 or 2, wherein the polypropylene resin (A) is polymerized using a metallocene catalyst.   The heat-seal resin according to any one of claims 1 to 3, wherein the elastomer (C) is an ethylene-α-olefin copolymer and / or a styrene-based elastomer and / or a propylene-α-olefin copolymer. Composition.   The film which consists of at least 1 layer, Comprising: A heat seal layer is a film which consists of the resin composition for heat seals of any one of Claims 1-4. The film according to claim 5, wherein the film is for a multi-chamber bag for infusion.