JP3315015B2 - Polypropylene sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene sheet for press-through-pack packaging (hereinafter abbreviated as PTP packaging) used for packaging pharmaceuticals such as tablets and capsules.

[0002]

2. Description of the Related Art PTP packaging is a packaging form used for packaging pharmaceuticals such as tablets and capsules. A plastic sheet is formed into a required pocket shape, and the contents (tablets, capsules) are placed in the obtained pocket portion. Etc.), and the aluminum foil coated with the adhesive is sealed like a lid. The filled contents are pierced through the aluminum foil by pressing the sheet molding portion with a finger and taken out. Conventionally, as a base resin used for a PTP packaging sheet, polyvinyl chloride resin has been mainly used because of its excellent properties such as transparency, moldability, rigidity, curl after aluminum sealing, and cost. Was. However, in the case where the contents of the drug do not like to absorb moisture, the polyvinyl chloride resin is inferior in moisture-proof property. Therefore, by coating a polyvinylidene chloride resin having excellent moisture-proof property on the polyvinyl chloride resin sheet, the moisture-proof property is improved. There is a way to improve it. Also, a method has been proposed in which the PTP package itself is pyro-wrapped with aluminum to improve the moisture resistance. However, since both methods require a lot of man-hours and increase costs, studies are being made to improve such methods. Further, in recent years, polyvinyl chloride resins and polyvinylidene chloride resins have been problematic from an environmental point of view in that chlorine gas is generated during incineration, and are currently being avoided. Due to the problems described above, P-substitutes that replace polyvinyl chloride resin or polyvinylidene chloride resin
The study of polypropylene resin as a material for TP was conducted.
Actually, polypropylene resin is partially used. However, polypropylene resin is superior in moisture resistance and cost as compared with polyvinyl chloride resin, but is inferior in moldability, transparency and impact resistance, and has a problem that curling after aluminum sealing is large. .

[0003] Above all, particularly with regard to moldability, polypropylene resin is inferior in moldability as compared with polyvinyl chloride resin. Generally, moldability is evaluated based on the temperature range in which molding is possible, and the polyvinyl chloride resin has a wider molding temperature range. As a method for improving the moldability, a method of adding a petroleum resin to a polypropylene resin (JP-A-59-143613, JP-A-2-302445) and a method of adding a random polypropylene to a polypropylene resin (JP-A-53-143) No. 66952) is known. In the former case, the moldability and transparency are improved, but when heated, it becomes sticky and becomes opaque, and the molding temperature range becomes narrower, and elongation occurs due to heating during molding, causing pitch shift. Therefore, there is a problem that uniform molding cannot be performed. In addition, curling occurs in the final product, which impairs commercial value and causes problems during integration. Also, with the increase in the amount of petroleum resin added, the amount of residual monomers and low molecular weight compounds using n-heptane as a solvent increases, and the Ministry of Health and Welfare Notification No. 2
Non-conformity with No. 0. In the latter case, the molding temperature range is widened by increasing the amount of addition, but there is a problem that the rigidity of the sheet decreases with the increase of the amount of addition. When a sheet having low rigidity is applied to a high-speed molding machine, there is a problem that the sheet is stretched due to strong tension applied to the sheet, and vertical wrinkles are generated. Therefore, the sheet needs to have such a rigidity that vertical wrinkles are not generated in the sheet, and it has conventionally been difficult to suppress curl and maintain formability while maintaining the rigidity of the sheet.

The impact resistance of homopolypropylene alone is low at both room temperature and low temperature. As a method for improving impact resistance, a method of adding random polypropylene to homopolypropylene and a method of adding a thermoplastic elastomer are known. In the former case, the impact at room temperature is greatly improved, but at low temperatures, the impact is hardly improved. In the latter case, the impact resistance is improved with an increase in the amount of addition, but at the same time, there is a problem in that the rigidity, the moisture resistance and the transparency are reduced. Regarding curl, polypropylene resin has a larger linear expansion than polyvinyl chloride resin, so it shrinks significantly after sealing with aluminum.As a result, the product curls to the opposite side of the aluminum foil and impairs product value. There has been such a problem that troubles such as inability to accumulate on a packaging line occur. A method for improving curl has been made in a multilayer sheet, and a method for increasing curl and improving curl by using highly rigid and highly crystalline polypropylene for the outer layer (Japanese Patent Laid-Open No. 5-64864). A method in which the rigidity is increased by using a highly rigid and highly crystalline polypropylene for the outer layer, and a random polypropylene is introduced into the inner sealant layer to lower the sealing temperature and suppress curling (Japanese Patent Laid-Open No. Hei 5-17025).
No. 9). In the former method, the curl is hardly improved, and in the latter method, the curl is improved, but on the contrary, the formability and transparency of the sheet are significantly deteriorated,
A sheet that could withstand actual use could not be obtained. As described above, in contrast to the required performance of a PTP sheet such as rigidity, impact resistance, transparency, moldability, moisture resistance, and low curl after aluminum sealing, the conventional polypropylene sheet has Even if a certain required performance can be satisfied, the other required performance cannot be satisfied, and there is no polypropylene-based sheet that can satisfy all the above required performances. .

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made as a result of various studies in order to solve the above-mentioned problems. The object of the present invention is to provide a polypropylene homopolymer with a crystal nucleating agent, a petroleum resin, and ethylene. -By adding propylene random copolymer, hydrogenated styrene-butadiene copolymer or hydrogenated styrene-isoprene copolymer, excellent rigidity, impact resistance, moisture resistance, transparency, moldability,
An object of the present invention is to provide a polypropylene-based sheet for PTP which conforms to the Ministry of Health, Labor and Welfare Notification No. 20 and in which curling after aluminum sealing is suppressed more than before.

[0006]

The present invention relates to a polypropylene homopolymer (hereinafter abbreviated as homopolypropylene) having a nucleating agent content of 0.002 to 0.3% by weight (wt%).
84 wt%, ethylene-propylene random copolymer having an ethylene content of 0.1-5.0 wt% (hereinafter abbreviated as random polypropylene) 10-25 wt%, petroleum resin 1-
A polypropylene-based sheet for PTP, comprising 8 wt% and 5 to 10 wt% of a thermoplastic elastomer.

The crystal nucleating agent used in the present invention is an organic nucleating agent or a high melting point polymer nucleating agent, and is added for the purpose of imparting rigidity and improving transparency. Crystal nucleating agents include organic nucleating agents, inorganic nucleating agents, and high melting point polymer nucleating agents, but inorganic nucleating agents cannot be used because they hinder transparency. Examples of the organic nucleating agent include sorbitol derivatives, metal salts of dicarboxylic acids, metal salts of aromatic carboxylic acids, and metal salts of organic phosphoric acids. Examples of the high melting point polymer nucleating agent include polyvinylcyclohexane, polyvinylcyclopentane, poly-3-methylpentene-1, poly3-methylbutene-1, and alkenylsilane. These nucleating agents are known, and any one may be used as long as it is other than the inorganic crystal nucleating agent. These crystal nucleating agents are added in a volume
002 to 0.3% by weight. When no crystal nucleating agent is added, the rigidity is remarkably reduced, causing problems such as generation of vertical wrinkles in the sheet during actual use. 0.002 added
When the content is less than 0.3% by weight, the effect of adding a nucleating agent is not obtained.
%, The effect cannot be expected to increase even if added. The above nucleating agent is added to homopolypropylene. The addition may be performed at the time of polymerization or after the polymerization.

The homopolypropylene used in the present invention can be produced by any polymerization method (eg, solvent polymerization method, bulk polymerization method, gas phase polymerization method) or any catalyst (titanium trichloride type catalyst, magnesium chloride supported type catalyst, metallocene catalyst). It may be manufactured. The homopolypropylene used in the present invention is used for imparting rigidity. Addition amount is 5
7 to 84% by weight (wt). If the addition amount is 57% by weight or less, the rigidity is remarkably reduced, and if it is 84% by weight or more, the molding temperature width is not widened. The random polypropylene used in the present invention is produced by any polymerization method (solvent polymerization method, bulk polymerization method, gas phase polymerization method), and any catalyst (titanium trichloride type catalyst, magnesium chloride supported type catalyst, metallocene catalyst). But it is good. These random polypropylenes are added for the purpose of widening the molding temperature range.
Some random polypropylenes have various ethylene contents, and among them, the ethylene content is 0.1%.
1 to 5.0 wt% of random polypropylene is suitable, and the addition amount is preferably 10 to 25 wt%. When the ethylene content is 0.1 wt% or less, the molding temperature width does not widen,
If the content is 5.0 wt% or more, the rigidity and moisture resistance of the sheet are significantly reduced. The amount of random polypropylene added is 10 wt%
Below, the molding temperature width does not widen, and when the addition amount is 25 wt% or more, the rigidity of the sheet and the moisture resistance are significantly reduced.

The thermoplastic elastomer used in the present invention is a natural or synthetic polymer which exhibits elasticity in a room. Specifically, natural rubber, polybutadiene, polyisoprene, polychlorobutadiene, styrene-butadiene copolymer (including all random copolymers, block copolymers, graft copolymers, etc.), styrene-isoprene copolymer ( Random copolymer, block copolymer, graft copolymer, etc.), acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-
Diene terpolymer, ethylene-propylene-butene terpolymer, thiolol rubber, polyvulcanized rubber, polyurethane rubber, polyether rubber, epichlorohydrin rubber, etc., and polymers obtained by hydrogenating these thermoplastic elastomers, such as hydrogenated styrene -Butadiene copolymer and hydrogenated styrene-isoprene copolymer. The thermoplastic elastomer used in the present invention is added for the purpose of improving impact resistance, and among them, a hydrogenated styrene-butadiene copolymer or a hydrogenated styrene-isoprene copolymer is preferable. The addition amount of these thermoplastic elastomers is 5-1.
0 wt%. If the addition amount is 5 wt% or less, the impact resistance is poor and it is not practical. If the addition amount is 10 wt% or more, the rigidity and moisture resistance of the sheet are significantly reduced. In these thermoplastic elastomers, the styrene content is 11 to 35.
% Hydrogenated styrene-butadiene copolymer or hydrogenated styrene-isoprene copolymer is desirable. When the styrene content is 11% or less, there is no effect of improving the impact property,
%, Transparency deteriorates. These hydrogenated styrene-
Butadiene copolymer or hydrogenated styrene-isoprene copolymer can be obtained by any polymerization method (eg, emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization), any catalyst (eg, peroxide, trialkylaluminum, lithium halide,
(Nickel-based catalyst). As the hydrogenation catalyst, noble metals such as palladium and platinum are converted to silica,
A catalyst supported on diatomaceous earth or the like, or a catalyst comprising a titanium compound and an organic metal compound (lithium, aluminum, etc.) is used.

The petroleum resin used in the present invention is added to improve transparency, moldability, moisture resistance and rigidity. Petroleum resins can be roughly classified into those based on synthetic resins and those based on natural resins. Examples of synthetic resins include aliphatic, aromatic hydrocarbon resins, alicyclic saturated hydrocarbon resins, and copolymers. And the like, and an alicyclic saturated hydrocarbon resin is desirable from the viewpoint of odor and transparency. In the present invention, 1 to 8 wt.
%Added. If the addition amount is 1 wt% or less, no effect is observed on moldability, moisture-proof property, transparency and rigidity. If the addition amount is 8 wt% or more, the impact resistance is poor, and the extraction amount of residual monomers and low molecular weight compounds using n-heptane as a solvent is 150%.
It does not conform to Ministry of Health and Welfare Notification No. 20 because it exceeds ppm.

Although the method for producing the polypropylene sheet of the present invention is not particularly limited, extrusion molding is preferred, and other resin layers may be provided on both sides of the sheet as long as the performance is not impaired. In the present invention, if necessary, additives within a range not impairing the basic properties, such as stabilizers, antistatic agents, ultraviolet absorbers, antioxidants, lubricants, fillers, dyes, pigments, neutralizing agents, A slip (anti-blocking agent) or the like may be added. The overall thickness of the sheet of the present invention is not particularly limited,
It is in the range of 0.5 mm, and particularly in the range of 0.25 to 0.4 mm is appropriate as the thickness of the PTP sheet.

[0012]

EXAMPLES The present invention will be described below by way of examples, which are merely examples, and the present invention is not limited to these examples. The blends shown in Tables 1 and 2 were carried out, the polypropylene resin was extruded using an extruder having a screw diameter of 65 mm, and a metal-made cooling roll and a metal touch roll were formed using a single-layer die. And the surface was mirror-finished. The thickness of the sheet was set to 300 μm. The evaluation results of Examples and Comparative Examples of the present invention are shown in Tables 3, 4 and 5 below.

* Ingredients used in Examples and Comparative Examples-Propylene homopolymer (Homopolypropylene) HP-1 Chissopolypro HT-6004 manufactured by Chisso Corporation (crystal nucleating agent content 0.3 wt%) HP-2 Mitsui Noblen JS-G Manufactured by Mitsui Toatsu Chemicals Co., Ltd. (no crystal nucleating agent added)-Ethylene-propylene random copolymer (random polypropylene) EPR-1 Ethylene content 2 wt% MI = 1.5 EPR-2 Ethylene content 5 wt% % MI = 1.2 EPR-3 Ethylene content 51 wt% MI = 8.0-Thermoplastic elastomer-Hydrogenated styrene-butadiene copolymer HSBR-1 Dinalon 1910P Nippon Synthetic Rubber Co., Ltd. (styrene content 30 wt%) HSBR-2 Dynallon 1320P manufactured by Nippon Synthetic Rubber Co., Ltd. (styrene・ Hydrogenated styrene-isoprene copolymer SEPS-3 Hibler HVS-3 Kuraray Co., Ltd. (styrene content 30 wt%) ・ Petroleum resin P-1 Alcon P125 Arakawa Chemical Industry Co., Ltd. (Cyclic saturated hydrocarbon compound) ・ Crystal nucleating agent N-1 Gerol D manufactured by Shin Nippon Rika Co., Ltd. (dibenzylidene sorbitol)

Table 1 Example 1 2 3 4 5 6 HP-1 70 80 84 57 70 HP-2 69.7 EPR-1 20 10 25 20 20 EPR-2 10 HSBR-1 5 5 5 10 5 SEPS-15 P-1 55 1 8 5 5 N-1 0.3 Table 2 Comparative Example 1 2 3 4 5 6 7 8 9 10 10 HP-1 85 40 90 80 75 65 72 60 70 HP-270 EPR-1 5 50 20 20 20 20 20 20 EPR-3 10 HSBR-1 55 5 5 5 5 5 3 15 5 HSBR-25 P-1 5 5 5 5 10 5 5 5 5

Each evaluation method is as follows. Evaluation of rigidity Olsen's flexural rigidity was measured according to JIS-K-7106. -Evaluation of impact resistance DuPont impact value was measured according to JIS-K-7221.・ Evaluation of transparency Regarding light transmittance, haze and internal haze, JIS-K-
Measured according to 6714. -Evaluation of n-heptane extraction Measured according to the Ministry of Health and Welfare Notification No. 20.・ Evaluation of moldability CB Co., Ltd. Blister pack molding machine FB
The number of shots was fixed at 80 shots / minute using PM2, and the molding temperature was increased from 138 ° C to 150 ° C in 2 ° C increments, and molding was performed at each molding temperature. Molding was performed by plug-assist air pressure molding using a mold having a pocket shape of 10 mmφ at the bottom, 9 mmφ at the top, 4.1 mm in depth, and 10 pockets per shot. The moldability was evaluated based on the molding temperature range. The molding temperature width was determined by comprehensive evaluation of the mold followability to the molding die, the appearance unevenness of the pocket top portion, and the thickness of the top portion. The mold followability and the appearance unevenness of the top were determined by visual sensory evaluation, and the thickness of the top was determined by measurement using a dial gauge.

Evaluation of curl Under the above conditions, molding was performed under conditions showing good moldability, and the contents were sealed with an aluminum foil at 180 ° C. without filling.
After putting in a slitter at 37 ° C, width 37mm, length 94m
m, a molded product punched at a corner of 5 mmR was placed on a flat surface, and the warpage of the molded product 10 minutes after punching was measured. The six molded articles were measured at six locations beside each molding pocket and averaged to obtain an evaluation. The aluminum foil used was a 20 μm hard aluminum foil coated with 5 μm of maleated polypropylene.・ Evaluation of moisture resistance The sheet is vacuum-formed into a cup and filled with silica gel.
Sealed with aluminum foil, stored in a thermo-hygrostat adjusted to 40 ° C and 90% RH for 10 days, 1 m ² , 24
The change in weight per hour was determined and evaluated.

Table 3 Example Test item (unit) 1 2 3 4 5 6 Flexural rigidity MD 12600 12300 13800 10000 12600 10000 (kgf / cm ² ) TD 12000 11900 13500 9800 12000 10000 Dupont impact value 23 ° C 10.8 11.9 12.0 20.8 10.8 10.3 (kgf · cm) -20 ℃ 6.7 7.8 7.9 10.3 6.7 5.1 moisture permeability ^{(g / m 2 · 24hr)} 0.50 0.53 0.65 0.60 0.50 0.55 light transmittance (%) 91.9 91.6 91.7 91.9 91.6 91.7 haze (%) 12.3 11.5 13.1 14.1 11.5 9.0 Internal haze (%) 10.4 9.6 11.2 11.2 9.6 7.1 Formability (° C) 8 8 7 9 8 8 Curl (mm) 2.0 2.0 1.8 1.5 2.0 2.4 n-Heptane extraction (ppm) 56 58 4 125 59 119

Table 4 Comparative example Test item (unit) 1 2 3 4 5 Flexural rigidity MD 14100 6200 13600 8900 12600 (kgf / cm ² ) TD 13600 6000 13000 8500 12000 Dupont impact value 23 ° C 9.9 15.0 14.0 17.8 12.3 (kgfcm)- 20 ℃ 4.9 7.8 6.9 8.5 6.5 moisture permeability ^{(g / m 2 · 24hr)} 0.52 0.85 0.45 0.80 0.78 light transmittance (%) 91.4 91.6 91.7 91.8 91.9 haze (%) 13.0 14.5 12.3 10.5 14.5 internal haze (%) 11.0 12.6 9.0 8.6 9.8 Moldability (° C) 1 12 0 8 5 Curl (mm) 2.0 3.5 3.2 3.6 2.5 Extraction of n-heptane (ppm) 11 148 35 160 1

Table 5 Comparative example Test item (unit) 6 7 8 9 10 Flexural rigidity MD 12300 13000 7500 12500 7800 (kgf / cm ² ) TD 10900 12900 7800 12100 7500 Dupont impact value 23 ℃ 7.7 7.5 28.0 4.8 12.6 (kgf ・ cm)- 20 ℃ 3.8 2.2 15.0 1.9 9.7 moisture permeability ^{(g / m 2 · 24hr)} 0.44 0.52 0.81 0.57 0.75 light transmittance (%) 91.6 91.7 88.8 91.9 91.7 haze (%) 11.5 12.3 16.1 10.9 23.0 internal haze (%) 8.7 9.0 14.2 9.0 15.6 Formability (° C) 8 7 7 8 9 Curl (mm) 2.2 2.8 1.9 2.9 4.5 Extraction of n-heptane (ppm) 178 51 159 56 118

Evaluation Results The embodiments of the present invention all satisfy the required performance.
Comparative Example 1 is inferior in moldability, and Comparative Example 2 is inferior in rigidity, moisture resistance and curl. Comparative Example 3 is inferior in moldability and curl, and Comparative Example 4 is inferior in rigidity, moisture resistance, curl, and extraction with n-heptane. Comparative Example 5 is inferior in moisture resistance and moldability, and Comparative Example 6 is inferior in impact resistance and extraction with n-heptane. Comparative Example 7 is inferior in impact resistance, and Comparative Example 8 is inferior in rigidity, transparency, and extraction with n-heptane. Comparative Example 9 is inferior in impact resistance. Comparative Example 10 is inferior in rigidity, moisture resistance, transparency and curl.

[0021]

According to the method of the present invention, rigidity, moisture resistance,
It is excellent in transparency, moldability, and impact resistance, can obtain a sheet conforming to the Ministry of Health and Welfare Notification No. 20, and can suppress curling after aluminum sealing more than conventional polypropylene sheet. Suitable for use as a polypropylene-based sheet.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 57:02) C08L 57:02)

Claims (3)

(57) [Claims] 1. An ethylene-propylene random copolymer having a nucleating agent content of 0.002 to 0.3% by weight of a polypropylene homopolymer of 57 to 84% by weight and an ethylene content of 0.1 to 5.0% by weight. 10-25% by weight, petroleum resin 1-8
A polypropylene-based sheet for PTP, comprising 5% by weight and 5 to 10% by weight of a thermoplastic elastomer. 2. The thermoplastic elastomer is a hydrogenated styrene-butadiene copolymer having a styrene content of 11 to 35% by weight or a hydrogenated styrene-isoprene copolymer having a styrene content of 11 to 35% by weight. The polypropylene sheet according to claim 1, 3. The polypropylene sheet according to claim 1, wherein the petroleum resin is an alicyclic saturated hydrocarbon resin.