JP2711540B2 - Heat sealing lid material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat-sealing lid material. More specifically, a so-called structure in which a solid container is mainly composed of a plastic container and an aluminum foil cover material, and the aluminum foil cover material is ruptured by pressing the bottom of the container to take out the contents. PTP packaging (Press
The present invention provides a heat-sealing lid material that is suitably used when the container is a polyolefin-based plastic, particularly a polypropylene-based plastic in Through Pack). (Prior art) A PTP packaging container consists of two parts: an aluminum foil that serves as a lid and a plastic sheet that forms a pocket to hold the contents. The aluminum foil used for the lid material has text on one or both sides as required. Heat-sealed so that it can be printed and printed on one side, with a transparent overcoat on one side if necessary, and a plastic sheet on the other side that can be bonded by heat and pressure to a container with a pocket. Applying a resin composition or paint
It is common practice to form a heat seal adhesive layer having a thickness of at most 5-6 μm. As a plastic forming the container body, a vinyl chloride resin sheet is used because of its excellent workability. In recent years, however, it has been replaced by a polypropylene sheet because of its excellent moisture-proof property and low cost. As described above, the heat seal layer provided on the aluminum foil used for the lid material is generally formed by applying a thermoplastic resin composition or paint, but recently, in order to stabilize heat seal strength and quality. A method of forming a heat seal layer by attaching a film of a thermoplastic resin having heat sealability to aluminum foil as it is or using an adhesive has come to be performed,
Poly-α-olefins such as polyethylene and polypropylene, α-olefin mutual copolymers such as ethylene and propylene or other α-olefins such as butene-1, hexene-1, 4-methylpentene-1, octene-1 and the like , Ionomers composed with metal ions such as sodium or zinc ions such as metal salts of ethylene- (meth) acrylic acid copolymers, vinylidene chloride copolymers, polyvinyl acetate, vinyl chloride-vinyl acetate Various (co) polymer films such as copolymers, ethylene-vinyl acetate copolymer (EVA) and the like are used for the purpose. (Problems to be Solved by the Invention) However, in order to form a heat-sealing layer on aluminum foil, various resin compositions or coatings mainly composed of a polymerized or condensed thermoplastic resin have been studied and used. However, when the container of the other party is made of polyolefin such as polypropylene, there is no material showing sufficient heat sealing strength, and since the lid material is curled during heat sealing processing, it is difficult to apply to the automatic packing device and the work process For example, when the heat sealing temperature is lowered to reduce curling, there is a problem that the adhesive strength cannot be obtained. When a heat-sealable thermoplastic resin film is applied to form a heat-sealable layer, when the heat-seal strength is high, the effect of reinforcing aluminum foil is large and the lid material is easy even when the bottom of the container is pressed. If the rupture strength of the lid material is properly adjusted, the heat sealing strength between the lid material and the container will be weakened, and if the aluminum foil is thin, there is no reinforcing effect and it will be damaged in the normal handling process It is a fact that there is no satisfactory countermeasure due to problems such as easy operation. (Means for solving the problem) In order to solve such a problem, the present inventors have found that the heat seal strength of PTP packaging using a polyolefin resin sheet, particularly a polypropylene sheet, as the material of the container is sufficient. It can be easily ruptured by pressing the bottom of the container and the contents can be easily taken out.Moreover, it has a strength that does not cause breakage in normal handling, and furthermore, it has a curl that occurs during heat sealing. The inventors of the present invention have conducted intensive studies for the purpose of developing a heat-sealing lid material with less heat, and as a result, have reached the present invention. That is, the present invention relates to a heat-sealing lid material for PTP packaging used to cover the opening of a polyolefin packaging container for PTP packaging by heat sealing, wherein the propylene (co) polycarbonate having a carboxyl group is provided. Coalescing (A)
A resin mixture (C) consisting of 50 to 95% (indicating a weight percent, the same applies to all the above) and 5 to 50% of a styrene copolymer (B) composed of styrene and a diene monomer [provided that (A) + ( B) = 100%], and a heat-sealing film formed by molding a composite material laminated on an aluminum foil, wherein the heat-sealing film has a thickness of 10 to 50 μm,
Aluminum foil thickness is 5 ~ 25μm, composite material thickness is
The present invention relates to a heat sheet lid material having a thickness of 15 to 60 μm. With such a configuration, it has excellent heat sealing strength as a lid material of a polyolefin, especially polypropylene PTP packaging container, and has excellent rupture property of the lid material by pressing the bottom of the container, and can be used in normal handling. The inventors of the present invention have found that they have sufficient strength not to be damaged and that the curl generated by heat sealing is extremely small. Particularly, in the heat-sealing lid material of the present invention, the thickness of the heat-sealing film is 10 to 50 μm, the thickness of the aluminum foil is 5 to 25 μm, and the thickness of the composite material is 15 to 60 μm. Excellent in properties and curl prevention effect. The propylene (co) polymer (A) having a carboxyl group, which is a component of the resin mixture (C) for forming the heat sealable film constituting the heat sealable lid material of the present invention, is a propylene (co) polymer. It is obtained by adding or grafting a polymerizable unsaturated carboxylic acid.
Propylene (co) polymers include propylene homopolymers, random copolymers, block copolymers, and graft copolymers. Even in homopolymers, physical properties differ depending on the amount of isotactic component and molecular weight distribution. In the case of a copolymer, there are copolymers with various comonomer such as olefin monomer or gen monomer or (meth) acrylic acid ester, for example, ethylene is used as a comonomer. In this case, a variety of physical properties can be obtained depending on the ethylene content and the polymerization mode, and addition or grafting of a monomer having a functional group, for example, a monomer having a hydroxyl group, an epoxy group, an amide group, or the like. According to the modification such as the modification, the physical properties can be remarkably changed. All of these propylene (co) polymers can be used, and these propylene (co) polymers are not polymerizable with maleic acid, fumaric acid, (meth) acrylic acid, crotonic acid, itaconic acid, etc. A carboxylic acid-containing propylene (co) polymer can be obtained by introducing a saturated carboxylic acid by addition reaction or grafting. All of these propylene (co) polymers having a carboxyl group can be used, and the degree of compatibility with the styrene (co) polymer (B) combined to produce the resin mixture (C), the melting point, the secondary An appropriate one should be selected in consideration of various physical properties such as a transition point. Styrene and butadiene as styrene copolymer (B) comprising styrene and a diene monomer, which are other components of resin mixture (C) for forming a heat sealable film constituting the heat sealable lid material of the present invention, There are copolymers with diene monomers such as isoprene and cyclopentadiene, and various physical properties can be obtained depending on the polymerization mode such as random copolymerization, graft copolymerization and block copolymerization. Other components blended in the above, ie, propylene having a carboxyl group (co)
It is necessary to appropriately select in consideration of various physical properties of the polymer (A). In forming the heat-sealing film constituting the heat-sealing lid material of the present invention, the resin mixture (C) is mixed with a compounding agent generally used in the production of a plastic film, such as a dye, a pigment, a filler, a lubricant, and a foam. Addition of agents, antioxidants, plasticizers, etc., can be used as needed without any problem. For example, when a foaming agent is added to the resin mixture (C) and molded, a heat-sealable foamed film is obtained. However, since the film has cushioning properties, the adhesiveness to an uneven substrate surface is improved. Means used for ordinary plastic films, such as expected improvement, are applied almost as they are. The method for forming the heat-sealing film used in the heat-sealing lid material of the present invention is not particularly limited, and any of ordinary film forming methods such as a casting method, an inflation method, a T-die extrusion method, and a calendar method are applicable. In addition, almost any conventional processing method can be used, such as a method in which rupture properties can be given directionality by adding stretching. The thickness of the heat-sealable film should be appropriately set in consideration of the thickness of the aluminum foil to be laminated and the thickness and price of the heat-sealable lid material as a product. A material having a thickness of 10 to 50 μm is used in consideration of strength and a molding method. As described later, the thickness of the heat-sealing film is set to 10 in consideration of reducing the curl generated during the heat sealing.
To 50 μm. But particularly preferably 10 to 30
It is preferably set to μm. The material of the aluminum foil used in the heat-sealing lid material of the present invention is not particularly limited, and any of hard and soft materials can be applied. However, regarding the thickness, for example, aluminum foil alone used for PTP
Although it can be used as it is in the range of 30 to 30 μm, the strength of the entire material is improved by being laminated with the heat-sealing film, and considering that it is difficult to burst, in the present invention, the range of 5 to 25 μm is set. I have. The thickness of the heat-sealable film and the aluminum foil is set so that the total thickness of the heat-sealable lid obtained by laminating the heat-sealable film and the aluminum foil, which is the object of the present invention, is in the range of 15 to 60 μm. The lamination method is not particularly limited, and any ordinary laminator can be used. At the time of lamination, a heat-sealing film may be directly heat-pressed to an aluminum foil, but an adhesive for lamination is generally used. As the lamination adhesive, a commercially available organic solvent-based or aqueous-based product can be arbitrarily used. Further, even if the aluminum foil to be laminated is pre-colored, printed with characters or designs, etc. on the laminating surface with the heat-sealing film in the same manner as in a normal PTP packaging material, there is no problem. Absent. (Operation and Effect) The propylene (co) polymer (A) which is a component of the resin mixture (C) for forming the heat sealable film constituting the heat sealable lid material of the present invention has the heat sealability of the present invention. It contributes to the heat-sealing adhesive strength to the heat-sealable film of the lid material and the adhesive strength to polyolefin-based, especially polypropylene-based substrates, and the performance of general plastic films such as film strength and heat resistance. It mainly depends on this propylene (co) polymer (A). The styrene (co) polymer (B), which is another component resin of the resin mixture (C), is mixed with the propylene (co) polymer (A) at a predetermined ratio to form a resin mixture (C). Has the effect of reducing the rupture resistance of the heat-sealable film obtained by molding the resin, when the bottom is pressed to open the container when the heat-sealable lid of the present invention is used as a lid for PTP. The resistance of the steel is reduced, and it can be easily ruptured. However, other general physical properties mainly depending on the propylene (co) polymer (A) are maintained without being reduced. The resin mixture (C) for forming the heat-sealing film constituting the heat-sealing lid material of the present invention comprises 50 to 95% of a propylene (co) polymer (A) and a styrene (co) polymer (B) 5 When the mixing ratio of the propylene (co) polymer (A) is less than 50% and the mixing ratio of the styrene (co) polymer (B) exceeds 50%, the resin mixture (C) is The heat-sealing adhesive strength of the heat-sealing film obtained by molding, particularly the heat-sealing adhesive strength to polyolefin-based substrates, is reduced. Propylene (co)
The mixing ratio of the polymer (A) exceeds 95% and styrene (co)
When the mixing ratio of the polymer becomes 5% or less, the resin mixture (C)
The strength of the heat-sealable film obtained by molding of the resin increases, and when the heat-sealable lid obtained by laminating the film on aluminum foil is used as the lid for PTP, it easily bursts even if the bottom of the container is pressed. No longer. Furthermore, since the heat-sealing film has excellent dimensional stability to heat, the heat-sealing lid material of the present invention shrinks even when exposed to a high-temperature atmosphere to deform the packaged object, There is no occurrence of peeling. The heat-sealing film is a resin mixture (C)
A translucent or opaque material can be obtained depending on the composition of the aluminum foil. By laminating it on the glossy side of the aluminum foil, it has the effect of suppressing the reflection of light rays and making it a matte surface. Since the degree of properties does not change, it can be made to have the same appearance as a matte surface by laminating it on the glossy surface of aluminum foil. In the present invention, the thickness of the heat sealable film is
It is 10 to 50 μm. That is, when the thickness is 10 μm or less, it is difficult to obtain a uniform film easily torn in the production of the film, and the heat-sealing lid obtained by laminating the film on aluminum foil, when performing heat sealing with the PTP container. The resulting curl is likely to be large. On the other hand, if it exceeds 50 μm, the rupture strength of the packaging material obtained by laminating the film on aluminum foil becomes large, and when it is used as a lid material for PTP, it does not burst easily even if the container bottom is pressed. . The thickness of the aluminum foil, which is another material constituting the heat-sealing lid material of the present invention, is 5 to 5 in the present invention.
It is 25 μm. In other words, when the thickness is 5 μm or less, the strength of the heat-sealing lid material of the present invention is not obtained, and it is easily broken by ordinary handling, and when it exceeds 25 μm, the burst strength becomes too large as a lid material for PTP. This is because, when heat sealing is not performed, a significant curl may be caused. The total thickness of the heat-sealable lid material obtained by laminating the heat-sealable film and the aluminum foil, which is the object of the present invention, is in the range of 15 to 60 μm. In other words, if the thickness is 15 μm or less, the strength is not sufficient, and if it exceeds 60 μm, the strength tends to be too high, so that it does not easily burst due to pressing when used as a PTP lid material, and the curl due to the difference in shrinkage ratio etc. during heat sealing. This is because there is a tendency to occur. Hereinafter, the present invention will be described in more detail with reference to examples. [Example 1] Tonply XG200 (carboxyl group-modified polypropylene copolymer manufactured by Mitsui Toatsu Chemicals, Inc., melt index)
2.0, specific gravity 0.91, Vicat softening point 135 ° C) 80 parts and Dialex HT-516 (a styrene copolymer containing diene monomer manufactured by Mitsubishi Moncite Chemicals, Ltd., melt index)
2.2, specific gravity 1.05, Vicat softening point 94 ° C) and mix with 20 parts to make a resin mixture, using a blown film extruder, cylinder temperature 160 ° C, die temperature 200 ° C A 20 μm heat sealable film was produced. The thickness of the obtained film is 20 μm.
Using a two-component polyurethane-based dry lamination adhesive (Takelac A310 / Takenate A-3, manufactured by Takeda Pharmaceutical Co., Ltd.) on the soft aluminum foil of Example 1, and the heat-sealing lid material of Example 1. It was created. [Examples 2 to 3] The same heat-sealing film as in Example 1 having a thickness of 30 μm and a thickness of 40 μm, respectively,
A heat-sealing lid material of Examples 2 and 3 was prepared by bonding the same to a soft aluminum foil of μm in the same manner as in Example 1. Example 4 A resin mixture was prepared by mixing 90 parts of Romply XG200 and 10 parts of Dialex HT-516 in Example 1.
A heat-sealable film having a thickness of 30 μm was produced. The thickness of the obtained film was 15 μm in the same manner as in Example 1.
To form a heat-sealable lid material of Example 4. Example 5 A resin mixture was prepared by mixing 55 parts of Romply XG200 and 45 parts of Dialex HT-516 in Example 1.
A heat-sealable film having a thickness of 30 μm was produced. The thickness of the obtained film was 15 μm in the same manner as in Example 1.
To form a heat-sealable lid material of Example 5. [Comparative Example 1] In Example 1, using only Romply XG200,
A heat-sealable film having a thickness of 30 μm was produced. This was adhered to the same soft aluminum foil having a thickness of 15 μm as in Example 1 to obtain a heat-sealing lid material of Comparative Example 1. [Comparative Example 2] A resin mixture was prepared by mixing 45 parts of Romply XG200 and 55 parts of Dialex HT-516 in Example 1.
A heat-sealable film having a thickness of 30 μm was produced. The resulting film had low strength and was easily damaged during handling. An attempt was made to produce a film having a thickness of 20 μm, but the film could not be actually produced due to insufficient strength. Obtained thickness 30
A μm film was adhered to a soft aluminum foil having a thickness of 15 μm in the same manner as in Example 1 to obtain a heat-sealing lid material of Comparative Example 2. [Comparative Example 3] Hardlen 13-L (Toyo Kasei Kogyo Co., Ltd.) was used as a heat sealant for chlorinated polypropylene based polypropylene on a soft aluminum foil having a thickness of 15 μm in the same manner as in Example 1.
Chlorinated polypropylene solution, chlorine content 26%, non-volatile content 30% toluene solution) at 5 g / m ² and dried to create a heat-sealable lid used as a normal PTP lid. And Comparative Example 3. (Adhesion Strength Test) The heat-sealing lids of Examples 1 to 5 and Comparative Examples 1 to 3 were each applied to a 250 μm-thick polypropylene sheet (NS2400A, manufactured by Sumitomo Bakelite Co., Ltd.) at a heat-sealing temperature of 180 ° C. and a pressure of 3 kg /. Heat sealing was performed under the conditions of cm ² and a pressing time of 1 second to prepare a sample for an adhesive strength test.
The heat seal strength of these samples was measured by a 180 mm peel test with a width of 15 mm. The required adhesive strength varies depending on the application, but usually 1 kg / cm ² or more is required. The measurement results are shown in Table 1. The heat-sealable lid material using the heat-sealable film of Comparative Example 2 and the hard seal 13-L as a heat sealant were applied to form a heat seal layer. Although the power was low, all of those using the heat-sealing lid materials of Examples 1 to 5 were used.
A sufficient adhesive strength of 1 kg / cm ² or more was exhibited. Example 6 A heat-sealable film having a thickness of 7 μm and a hard aluminum film having a thickness of 20 μm were bonded together with the same resin mixture as in Example 4 using a dry lamination adhesive in the same manner as in Example 1. The heat sealing lid material of Example 6 was used. Example 7 A heat-sealable film having a thickness of 55 μm was prepared using the resin mixture used in Example 5, and this was bonded to a soft aluminum foil having a thickness of 5 μm in the same manner as in Example 1. 7 was obtained. [Example 8 and Reference Example 1] The heat-sealing film having a thickness of 30 µm obtained in Example 4, a hard full-minimum foil having a thickness of 4 µm, and the thickness, respectively.
A heat-sealing lid material of Example 8 and Reference Example 1 was obtained by laminating a soft aluminum foil of 30 μm in the same manner as in Example 1. [Reference Example 2] A heat-sealing film having a thickness of 45 µm was prepared using the resin mixture used in Example 5, and this was laminated with a soft aluminum foil having a thickness of 20 µm in the same manner as in Example 1 to obtain a thickness. A heat-sealing lid material of Reference Example 2 having a thickness of 65 μm was obtained. (Burst Strength and Tensile Strength Test) For each heat-sealing lid material of Examples 1 to 5 and 6 to 8, Comparative Examples 1 and 3, and Reference Examples 1 and 2, the burst strength (JIS P8112) and the width per 15 mm The tensile strength was measured, and each of the heat-sealing lids was 250 μm thick.
m polypropylene sheet (Sumitomo Bakelite Co., Ltd.)
NS2400A) at a temperature of 180 ° C and a pressure of 3 kg / cm ²
Heat sealing was performed for 2 seconds, and the degree of curl was expressed in mm as a chord length for an arc having a length of 20 mm and compared.
These results are listed in Table 2. If the burst strength exceeds ² kg / cm ² , the PTP package becomes difficult to break by pressing, and the handling strength may be ² kg / cm ² or more. Also, the degree of curling is preferably such that the chord length for the warpage of the 20 mm long portion of the material does not become 16 mm or less. It is recognized that it is particularly preferable that the thickness of the aluminum foil is 10 to 50 μm, and the total thickness of the aluminum foil is 5 to 25 μm is 15 to 60 μm. (Adhesive strength test) A pocket for storing a pharmaceutical capsule was formed on the polypropylene sheet having a thickness of 250 µm used in Example 5, and the capsule was stored using the heat-sealing lid material of Examples 1 to 5 as a lid. Then, it was heat-sealed at 180 ° C. at a heat-sealing pressure of 3 kg / cm ² for 1 second to prepare a PTP package. Both of them have sufficient strength as the lid material, but the lid material was easily ruptured by pressing the container part, and the capsule was easily taken out.

Continuation of front page    (72) Inventor Koji Nakahashi               9-151 Otashinmachi, Yao City, Osaka Prefecture               Leader Co., Ltd.                (56) References JP-A-62-64844 (JP, A)                 Jiko 60-36437 (JP, Y2)

Claims (1)

(57) [Claims] A heat-sealable lid material for PTP packaging used to cover the opening of a polyolefin packaging container for PTP packaging by heat sealing, wherein the propylene (co) polymer (A) has a carboxyl group. Styrene copolymer (B) consisting of styrene and a diene monomer of 5 to 50%
% (C) [where (A) + (B) =
100%], and a heat-sealing film formed by laminating the heat-sealing film on an aluminum foil. The heat-sealing film has a thickness of 10 to 50 μm, and the aluminum foil has a thickness of 5 to 25 μm. Material thickness is 15
A heat-sealing lid material having a thickness of from 60 to 60 μm