JP4614710B2 - Resin composition and film containing plate-like filler - Google Patents

Description

  The present invention relates to a resin composition for a lid of a push-through package and a film obtained from the composition. Specifically, the present invention relates to a polypropylene composition containing a plate-like filler such as clay (layered clay) that has been subjected to a predetermined treatment, and a film excellent in gas barrier properties and the like obtained from the composition.

   2. Description of the Related Art Push-through packages (PTP: Push Through Package) are widely used for packaging pharmaceuticals, foods, and the like. This is composed of a storage part formed by molding a plastic sheet and a cover part usually made of aluminum foil. PTP is obtained by storing contents such as medicines in the storage section and heat-bonding the flat portion at the upper end of the storage section and the lid using an adhesive. The contents stored in the PTP are taken out through the aluminum lid by pushing the storage portion with a finger.

  In the conventional PTP, since the lid is made of aluminum foil and the storage part is made of plastic, a separation process is required for disposal or recycling, which is cumbersome. Therefore, it has been desired that the lid material is also made of plastic. However, a normal plastic sheet is too strong as a lid material, and as it is, push-through properties when taking out the contents, that is, tablets in the storage portion. This means the ease of tearing of the lid when the content is taken out after being filled with the content and adhered to the lid.

As a method of imparting the push-through property to a plastic sheet, a method of blending an inorganic filler or the like with the sheet is known (Patent Documents 1 to 4).

However, the plastic sheet described in these documents is inferior to the various characteristics which aluminum foil has. For example, it is inferior in gas barrier properties for preventing moisture absorption of moisture in the contents and oxidation by oxygen. In addition, in the process of bonding the lid and the flat portion at the upper end of the storage unit by heating or the like, the heating efficiency of the bonding unit is poor, so the bonding processing speed is low and the productivity is low. When the heating temperature is increased in order to increase productivity, the PTP molding processability is impaired by inducing thermal deformation of the lid and / or the storage unit. Furthermore, even in the incineration after use, which is the original purpose of using plastic, the inorganic filler remains as ash in the furnace and causes accumulation or clogging. On the other hand, regarding the gas barrier property of the film, a method of improving the water barrier property by blending a plate-like filler has been proposed (Non-Patent Document 1), but the above push-through performance, moldability, etc. There is a problem.
JP 09-058744 A JP 09-240727 A JP-A-10-101132 JP-A-10-101133 Toyota Chuken Review Vol.29, No.1, 49-57 (March 1994)

  Therefore, the present invention is a resin composition having molding processability and disposal property suitable as a lid for PTP, a film excellent in gas barrier property and push-through property obtained from the composition, and obtained from the film An object is to provide a lid for PTP.

That is, the present invention includes a push-through containing a polypropylene resin and a plate-like filler having an average aspect ratio of 10 or more and an average major axis of 0.1 to 20 μm, based on 100 parts by weight of the polypropylene resin. A resin composition for a lid of a package.
Preferably, the polypropylene resin is a polypropylene homopolymer or a blend of a polypropylene homopolymer and an ethylene-cycloolefin copolymer. The plate filler is preferably selected from the group consisting of talc, kaolin, mica, clay, graphite, and glass flakes, more preferably graphite.
Moreover, this invention is a lid | cover of the film which consists of the said resin composition, and the push through package which consists of this film.

  The film of the present invention has excellent gas barrier properties and push-through properties, and is suitable as a lid for PTP. In particular, those containing graphite are excellent in waste disposal.

  The polypropylene resin used in the present invention includes a random copolymer or block copolymer with a propylene homopolymer or another monomer copolymerizable with propylene. These three-dimensional structures are not particularly limited, and may be isotactic, atactic, syndiotactic, or a polymer having a mixed structure thereof. Examples of other copolymerizable monomers include ethylene, butene-1, hexene-1, 4-methyl-pentene-1, α-olefins having 4 to 12 carbon atoms such as octene-1, and divinylbenzene, , 4-cyclohexadiene, dicyclopentadiene, cyclooctadiene, ethylidene norbornene and other dienes. Examples of the random copolymer include propylene-ethylene random copolymer and propylene-ethylene-butene-1 copolymer. Examples of the block copolymer include propylene-ethylene block copolymer and reactor type polypropylene. An elastomer etc. are mentioned. Also, two or more of these polypropylene resins, or other polyolefin resins such as ethylene homopolymers and copolymers, butene homopolymers and copolymers, 4-methyl-pentene-1 homopolymers and copolymers , Cycloolefin homopolymers and copolymers, etc. may be blended with a range that does not impair the properties of the polypropylene resin, generally 40% by weight or less of the total resin. Preferably, a polypropylene homopolymer or a blend of a polypropylene homopolymer and an ethylene-cycloolefin copolymer is used.

  The film of the present invention contains a filler. By including the filler, the thermal conductivity of the resin composition is increased, and the moldability is also improved. Furthermore, the filler in the present invention is plate-shaped. Permeation of gas is also disturbed to some extent by the spherical filler. However, since the plate-like filler is oriented in the machine direction during film formation, the resulting film has a higher gas barrier property. Further, it was found that the transmission of light is effectively blocked, so that the contents are excellently concealed. That is, the conventional PTP containing filler has a problem in that the display contents printed on the lid cannot be clearly identified because the contents of the PTP can be seen through the lid. On the other hand, since the film containing a plate-like filler has poor transparency and the contents are difficult to see, the printed display can be clearly identified. At the same time, alteration of the contents by light is also prevented. The plate shape includes a flat plate shape, a flake shape, and a scale shape. The aspect ratio of the plate-like filler (= major diameter of filler / filler thickness, hereinafter simply referred to as “aspect ratio”) is 10 or more, preferably 15 or more. When the aspect ratio is less than the lower limit, the effect of improving the gas barrier property is low. The major axis of the filler is about 0.1 to about 20 μm, preferably 0.3 to 15 μm. If the major axis is less than the lower limit, the effect of improving the gas barrier properties is low, and if it exceeds the upper limit, the strength suitable for the moldability and push-through performance of the polypropylene resin film may not be obtained. In the present invention, the major axis and the aspect ratio are an average major axis and an average aspect ratio measured with a stereomicroscope and averaged for 10 fillers, and hereinafter simply referred to as a major axis and an aspect ratio.

As fillers, talc, kaolin, mica, clay, sericite, glass flake, synthetic hydrotalcite, various metal foils, graphite, molybdenum disulfide, tungsten disulfide, boron nitride, plate-like iron oxide, plate-like calcium carbonate, Examples thereof include plate-like aluminum hydroxide. Of these, talc, kaolin, mica, clay, graphite, and glass flakes are preferable, and graphite is more preferable in that the waste treatment can be performed together with polypropylene.

  The added amount of the filler is 10 to 200 parts by weight, preferably 20 to 180 parts by weight with respect to 100 parts by weight of the polypropylene resin. When the amount added is less than the lower limit, the effect of improving gas barrier properties, push-through properties, and moldability is not sufficient, and when the upper limit is exceeded, the film strength, film moldability, and PTP moldability are impaired. There is. In order to improve the dispersibility of the filler in the resin, a surface treatment such as a fatty acid wax or a silane coupling agent may be applied according to the resin used in advance.

  In addition to the filler, the film of the present invention includes a filler compatibilizing agent, a weather resistance stabilizer, a heat resistance stabilizer, an antistatic agent, an antiblocking agent, a lubricant, a nucleating agent, a plasticizer, as long as the object of the present invention is not impaired. Additives such as agents, anti-aging agents, hydrochloric acid absorbents and antioxidants may be mixed as appropriate.

  The film of the present invention can be prepared by a known method. For example, after mixing and dispersing polypropylene resin pellets or powder and plate-like filler, if necessary, various additives using a Banbury mixer, etc., melt-kneading by a hot melt extrusion method, calendar method, hot plate press method, etc. The film is obtained by adjusting the thickness by adjusting the rolling force. Moreover, in order to improve dispersion | distribution of a plate-shaped filler, after mixing a filler with resin and melt-kneading with a twin-screw extruder, producing a master pellet, you may make into a film by the said film forming method. If there is a risk of the film breaking when the melt tension at the time of taking out the polypropylene resin film melted from the molding machine does not match the film transport speed, prepare a separate support film material and melt it into the support film. The polypropylene film may be temporarily heat-bonded and the support film may be peeled off after cooling.

  The thickness of the polypropylene resin film of the present invention is 0.01 to 0.2 mm, preferably 0.03 to 0.1 mm. If the film thickness is less than the lower limit, the moldability and strength of the polypropylene-based resin film, gas barrier properties are not sufficient, while if the upper limit is exceeded, push-through property, PTP molding processability may be impaired, Further, the gas barrier property is not high for the thickness, which is uneconomical.

The obtained film can be formed into a PTP lid by a known method. The storage part is formed by, for example, heating a hot plug of polypropylene homopolymer and pressurizing with pressure. The film of the present invention is sealed on the upper flat surface portion of the storage portion using a pocket-type roll and a heating nip roll. In addition, in order to improve adhesiveness with the bottom material which comprises a storage part, and / or display and pattern printability, the film of this invention has a propylene-butene copolymer, an acid, a hydroxyl group, an amino group, an epoxy group A thin film of a polypropylene resin modified with a functional group such as a low softening point, low crystallinity or low molecular weight polypropylene resin is laminated by a method such as coextrusion, extrusion lamination, thermal lamination, coating, etc. You may adhere | attach with a bottom material through the laminated | stacked film. Further, surface treatment such as flame treatment, corona treatment, or chromic acid treatment may be performed.

Hereinafter, the present invention will be described in more detail by way of examples.
Evaluation Method (1) Concealing Property The PTP prepared in the above-described molding processability evaluation was visually observed from the top of the lid material, and whether or not the outline of the tablet was clearly observed was evaluated according to the following criteria.
A: The outline of the tablet is not clearly observed.
B: The outline of the tablet is clearly observed.
(2) Gas barrier property According to JIS K-7129, the moisture permeability of the polypropylene resin film under 40 degreeC 90% relative humidity was measured, and the following determination was performed.
A: 0.8 (g / m ² ) / 24 hr or less.
B: 0.8 (g / m ² ) / 24 hr or more and 5 g / m 2/24 hr or less.
C: (g / m ² ) / 24 hr is exceeded.
(3) PTP molding processability Using a PTP molding machine, a polypropylene homopolymer sheet with a thickness of 0.4 mm is heated with hot plug and pressurized to form a storage part, and the contents (tablets) are loaded. A PTP was obtained by sealing the upper end edge of the storage portion and the lid with a nip roll of a roll and a heating roll. Here, the PTP molding conditions were a storage part molding process heat plug temperature of 180 ° C., a sealing process heating roll temperature of 230 ° C., and a machine speed of 3.8 m / min. The adhesion state of the edge of the obtained PTP storage part was evaluated by visual observation and the feel and strength of the lid material actually peeled by hand, and evaluated according to the following criteria.
A: Adhering without breakage, there was a large peeling resistance accompanied by deformation such as being cut off when the lid member was peeled off or partly taken off by the bottom material.
B: Adhered without breaking, but when the lid was peeled off, it was lightly peeled off without deformation or destruction of the lid.
C: It was broken or floated without being in close contact with the periphery other than the storage part, and peeled off without resistance.
(4) Push-through property The PTP storage part obtained by the above-described method was pushed with a finger to take out the contents, and sensory evaluation was performed according to the following criteria.
A: The contents could be taken out without being caught by the lid material that was torn by the same extrusion force as that of commercially available PTP of aluminum foil type. B: Either the extrusion force was large or there was a catch. C was able to take out the product: The extrusion force was large, and the contents could not be taken out easily. (5) Disposability The polypropylene resin film was put in a 700 ° C heating furnace and burned, and the remaining amount of combustion The following determination was made by visually evaluating the rate (= burning residue weight / pre-burning weight × 100) measurement and the state of sticking to the furnace.
A: Combustion remaining rate is 2% or less, no sticking to the furnace B: Combustion remaining rate is 2% or less, but sticking to the furnace C: Combustion remaining rate exceeds 2% ( 6) Film strength According to JIS K-7127, the tensile strength of the polypropylene resin film at a speed of 5 mm / min was measured at 23 ° C., and the following determination was made.
A: 10 MPa or more C: less than 10 MPa (7) Comprehensive evaluation Comprehensive evaluation was performed according to the following criteria.
A: No C in the above five evaluation items B: C1 in the above five evaluation items C: C2 or more in the above five evaluation items

To 100 parts by weight of a polypropylene homopolymer (melting point 165 ° C.), 50 parts by weight of mica (aspect ratio 40, major axis 15 μm) as a plate-like filler and 0.1 parts by weight of a phenolic antioxidant as additives are mixed. Using a T-die twin screw extruder, melt kneading and film extrusion at a cylinder temperature of 200 ° C. (supply side) to 250 ° C. (T die side) and a T die temperature of 240 ° C. Thus, a polypropylene resin film having a thickness of 0.20 mm was obtained.

  A point of adding 100 parts by weight of mica (aspect ratio 20; major axis 0.3 μm) as a plate-like filler, a point that the thickness of the polypropylene resin film was 0.02 mm, and cooling with a roll at 50 ° C. after the film extrusion molding At the same time, a PET film having a thickness of 100 μm was supplied along the cooling roll, and the polypropylene resin film was taken in a laminated state while being thermally fused with the PET film, and the PET film was peeled off after cooling. Except for the above, a polypropylene resin film was obtained in the same manner as in Example 1.

   A polypropylene resin film was obtained in the same manner as in Example 1 except that 20 parts by weight of glass flake (aspect ratio: 100, major axis: 5 μm) was added as a plate-like filler to form a 0.05 mm thick polypropylene resin film. It was.

   A polypropylene resin film was obtained in the same manner as in Example 2 except that 180 parts by weight of glass flake (aspect ratio 100, major axis 5 μm) was added as a plate-like filler to obtain a 0.05 mm thick polypropylene resin film. The

  A polypropylene resin film was obtained in the same manner as in Example 1 except that 50 parts by weight of graphite (aspect ratio 15 and major axis 10 μm) was added as a plate-like filler to obtain a polypropylene resin film having a thickness of 0.05 mm. .

A polypropylene resin film was prepared in the same manner as in Example 5 except that a mixed resin of 70 parts by weight of a polypropylene homopolymer (melting point 165 ° C.) and 30 parts by weight of an ethylene / cycloolefin copolymer (glass transition point 80 ° C.) was used. Obtained.

  The die was changed to a multi-manifold die, and a polypropylene resin film obtained in the same manner as in Example 5 and a propylene / butene copolymer (softening point 107 ° C.) were coextruded at a thickness of 0.05 mm. 0.003 mm, a total of 0.053 mm laminated polypropylene resin film was obtained. In the evaluation of PTP molding processability and push-through property, the propylene / butene copolymer side was used as the adhesive surface with the PTP bottom material.

  A polypropylene resin film was obtained in the same manner as in Example 2, except that 40 parts by weight of the polypropylene homopolymer and 60 parts by weight of the ethylene cyclic olefin random copolymer (glass transition point 105 ° C.) were used.

Comparative Example 1
Example except that 20 parts by weight of a spherical filler calcium carbonate (aspect ratio 1, long diameter 2 μm) was used in the blend composition described in JP-A-10-101133 and a polypropylene resin film having a thickness of 0.05 mm was used. In the same manner as in Example 2, a polypropylene resin film was obtained.

Reference example 1
A polypropylene resin film was obtained in the same manner as in Example 1 except that 50 parts by weight of mica (aspect ratio 40, major axis 30 μm) was added as a plate-like filler to obtain a 0.05 mm thick polypropylene resin film. .

Reference example 2
A polypropylene resin film in the same manner as in Example 1 except that 20 parts by weight of clay (aspect ratio of 100 or more, major axis 0.05 μm) was added as a plate-like filler to form a 0.05 mm thick polypropylene resin film. Got.

Reference example 3
A polypropylene resin film was obtained in the same manner as in Example 1 except that 5 parts by weight of graphite (aspect ratio: 15; major axis: 10 μm) was added as a plate-like filler to form a 0.05 mm thick polypropylene resin film. .

Reference example 4
A polypropylene resin film was obtained in the same manner as in Example 2 except that 250 parts by weight of graphite (aspect ratio 15 and major axis 10 μm) was added as a plate-like filler to obtain a 0.05 mm thick polypropylene resin film. .

Reference Example 5
A polypropylene resin film was prepared in the same manner as in Example 2 except that 50 parts by weight of mica (aspect ratio 20; major axis 0.3 μm) was added as a plate-like filler to obtain a 0.008 mm thick polypropylene resin film. Obtained. PTP could not be produced and PTP moldability could not be evaluated.

Reference Example 6
A polypropylene resin film was prepared in the same manner as in Example 1 except that 50 parts by weight of mica (aspect ratio 20; major axis 0.3 μm) was added as a plate-like filler to obtain a polypropylene resin film having a thickness of 0.25 mm. Obtained.

The evaluation results are shown in the following table.

As can be seen from the above table, the film obtained from the resin composition of the present invention is excellent in concealing property, gas barrier property, push-through property, etc., and is suitable as a lid for PTP.

Claims (5)

A push-through package comprising a composition comprising a polypropylene resin and a plate-like filler having an average aspect ratio of 10 or more and an average major axis of 0.1 to 20 µm, based on 100 parts by weight of the polypropylene resin. lid. The push-through package lid according to claim 1, wherein the polypropylene resin is a polypropylene homopolymer or a blend resin of a polypropylene homopolymer and an ethylene-cycloolefin copolymer . The push-through package lid according to claim 1 or 2, wherein the plate-like filler is at least one selected from the group consisting of talc, kaolin, mica, clay, graphite, and glass flakes . The lid of a push-through package according to claim 3, wherein the plate-like filler is graphite . The push-through package lid according to any one of claims 1 to 4, wherein the lid is a film having a thickness of 0.01 to 0.2 mm .