JPH08157659A - Polypropylene sheet - Google Patents

Abstract

PURPOSE: To prepare the polypropylene sheet for PTP, excellent in rigidity, impact resistance, moisture resistance, transparency, and moldability, fitting for the notification No.20 of the Ministry of Health and Welfare, and reduced in the curl after sealed with an aluminum foil in comparison with conventional sheets. CONSTITUTION: This polypropylene sheet for PTP comprises 57-84wt.% of a polypropylene homopolymer having a crystal-nucleating agent content of 0.002-0.3wt.%, 10-25wt.% of ethylene-propylene random copolymer having an ethylene content of 0.1-5.0wt.%, 1-8wt.% of a petroleum resin, and 5-10wt.% of a hydrogenated styrene-butadiene copolymer or a hydrogenated styrene- isoprene copolymer.

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 molded into a required pocket shape, and the contents (tablets, capsules) are formed in the obtained pocket portion. Etc.) and the aluminum foil coated with the adhesive is sealed like a lid. The filled contents are taken out by breaking through the aluminum foil by pushing the sheet molding portion with a finger. Conventionally, a polyvinyl chloride resin has been mainly used as a base resin used for a PTP packaging sheet because of its excellent performance such as transparency, moldability, rigidity, curl after aluminum sealing, and cost. It was However, when the drug that is the content dislikes moisture absorption, polyvinyl chloride resin is inferior in moisture resistance, so by coating polyvinylidene chloride resin with excellent moisture resistance on a polyvinyl chloride resin sheet, moisture resistance is improved. There is a way to improve it. Another method is to improve the moisture resistance by wrapping the PTP packaging itself with aluminum. However, since both methods require 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 an environmental problem that chlorine gas is generated during incineration treatment, and are currently being shunned. Due to the above-mentioned problems, P that replaces polyvinyl chloride resin and polyvinylidene chloride resin
Polypropylene resin was studied as a material for TP,
Actually, polypropylene resin is partially used. However, polypropylene resin is superior to polyvinyl chloride resin in moisture resistance and cost, but it is inferior in moldability, transparency and impact resistance, and there is a problem that curling after aluminum sealing is large. .

Among them, especially in terms of moldability, polypropylene resin is inferior in moldability to polyvinyl chloride resin. Generally, the moldability is evaluated by the temperature range in which molding is possible, and the polyvinyl chloride resin has a wider molding temperature range. As a method of improving moldability, a method of adding petroleum resin to polypropylene resin (JP-A-59-143613, JP-A-2-302445) or a method of adding random polypropylene to polypropylene resin (JP-A-53-53) No. 66952) is known. In the former case, the moldability and transparency are improved, but when heat-molded, it becomes sticky and becomes an opaque product, the molding temperature width becomes narrow, and elongation occurs due to heating during molding, causing pitch shift. Therefore, there is a problem that uniform molding cannot be performed. Further, since curl occurs in the final product, the product value is reduced, and there is a problem at the time of accumulation. In addition, as the amount of petroleum resin added increases, the amount of residual monomers and low molecular weight compounds extracted with n-heptane as a solvent increases, and the Ministry of Health and Welfare Notification No. 2
No conforming to No. 0. In the latter case, the molding temperature range is widened by increasing the addition amount, but there is a problem that the rigidity of the sheet decreases as the addition amount increases. When a low-rigidity sheet is applied to a high-speed molding machine, the tension applied to the sheet is strong, so that the sheet stretches and vertical wrinkles occur. Therefore, the rigidity of the sheet is required so that vertical wrinkles do not occur in the sheet, and it has been conventionally difficult to suppress the curl and maintain the formability while maintaining the rigidity of the sheet.

Regarding the impact resistance, homopolypropylene alone has a low impact resistance at both normal temperature and low temperature. As a method of improving impact resistance, a method of adding random polypropylene to homopolypropylene or a method of adding a thermoplastic elastomer is known. In the former case, the impact strength at room temperature is greatly improved, but the impact strength is hardly improved at low temperature. In the latter case, the impact resistance is improved as the amount added is increased, but at the same time, there is a problem that rigidity, moisture resistance and transparency are deteriorated. Regarding the curl, polypropylene resin has a larger linear expansion than polyvinyl chloride resin, so the contraction after aluminum sealing is large, so the product curls on the opposite side of the aluminum foil and reduces the commercial value. There is a problem that troubles such as inability to accumulate on the packaging line occur. A method for improving the curl has been made in a multilayer sheet, and a method for increasing the rigidity and improving the curl by using a highly rigid highly crystalline polypropylene for the outer layer (Japanese Patent Laid-Open No. 5-64864). And a method of increasing rigidity by using highly rigid and highly crystalline polypropylene for the outer layer and further introducing random polypropylene for the sealant layer of the inner layer to lower the sealing temperature and suppress curling (Japanese Patent Laid-Open No. 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,
We could not obtain a sheet that could be used in practice. As described above, in contrast to the required performance of the PTP sheet of rigidity, impact resistance, transparency, moldability, moisture resistance, and low curl after aluminum sealing, the conventional polypropylene sheet has There is a situation in which some required performances can be satisfied but other required performances cannot be satisfied, and there is no polypropylene-based sheet capable of satisfying all the above required performances. .

[0005]

The present invention has been made as a result of various studies in order to solve the above-mentioned problems. The object is to use a polypropylene homopolymer, a crystal nucleating agent, a petroleum resin, and ethylene. -By adding a propylene random copolymer, a hydrogenated styrene-butadiene copolymer or a hydrogenated styrene-isoprene copolymer, rigidity, impact resistance, moisture resistance, transparency and moldability are excellent,
An object of the present invention is to provide a polypropylene-based sheet for PTP which conforms to the Ministry of Health 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 having a crystal nucleating agent content of 0.002 to 0.3% by weight (wt%) (hereinafter abbreviated as homopolypropylene) 57 to.
84 wt%, ethylene-propylene random copolymer having ethylene content of 0.1 to 5.0 wt% (hereinafter abbreviated as random polypropylene) 10 to 25 wt%, petroleum resin 1 to
It is a polypropylene-based sheet for PTP characterized by comprising 8 wt% and a thermoplastic elastomer of 5-10 wt%.

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 impair transparency. Examples of the organic nucleating agent include sorbitol derivatives, metal salts of dicarboxylic acids, metal salts of aromatic carboxylic acids, metal salts of organic phosphoric acid, and the like. Examples of the high melting point polymer nucleating agent include polyvinyl cyclohexane, polyvinyl cyclopentane, poly 3-methylpentene-1, poly 3-methylbutene-1, and alkenylsilane. These crystal nucleating agents are known ones, and any one other than the inorganic crystal nucleating agent may be used. These crystal nucleating agents are
002-0.3 wt% is compounded. If the crystal nucleating agent is not added, the rigidity is remarkably reduced, and problems such as vertical wrinkles appearing on the sheet during actual use occur. Addition amount is 0.002
If it is less than wt%, there is no effect of adding a crystal nucleating agent,
%, It is not possible to expect an increase in effect even if added. The above crystal nucleating agent is added to homopolypropylene. The addition may be carried out during the 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 catalyst, metallocene catalyst). It may be manufactured. The homopolypropylene used in the present invention is used for imparting rigidity. Addition amount is 5
It is 7 to 84% by weight. When the addition amount is 57 wt% or less, the rigidity is remarkably reduced, and when the addition amount is 84 wt% or more, the molding temperature range 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) or any catalyst (titanium trichloride-type catalyst, magnesium chloride-supported catalyst, metallocene catalyst). But 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.
Random polypropylene of 1 to 5.0 wt% is suitable, and the addition amount thereof is preferably 10 to 25 wt%. When the ethylene content is 0.1 wt% or less, the molding temperature range does not spread,
If it is 5.0 wt% or more, the rigidity and moisture resistance of the sheet are significantly reduced. The addition amount of random polypropylene is 10 wt%
Below, the molding temperature range is not widened, and when the addition amount is 25 wt% or more, the rigidity of the sheet and the moisture resistance are significantly deteriorated.

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 copolymers, block copolymers, graft copolymers, etc. are all included), acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-
Diene terpolymers, ethylene-propylene-butene terpolymers, thiolol rubbers, polyvulcanized rubbers, polyurethane rubbers, polyether rubbers, epichlorohydrin rubbers and the like, and hydrogenated polymers of these thermoplastic elastomers such as hydrogenated styrene. -Butadiene copolymer and hydrogenated styrene-isoprene copolymer are mentioned. The thermoplastic elastomer used in the present invention is added for the purpose of improving impact resistance, and among them, hydrogenated styrene-butadiene copolymer or hydrogenated styrene-isoprene copolymer is preferable. The addition amount of these thermoplastic elastomers is 5 to 1
It is 0 wt%. If the addition amount is 5 wt% or less, the impact resistance is poor and it cannot be practically used. 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. If the styrene content is 11% or less, there is no effect of improving impact resistance,
If it exceeds%, the transparency deteriorates. These hydrogenated styrene-
The butadiene copolymer or hydrogenated styrene-isoprene copolymer may be used in any polymerization method (eg emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization), any catalyst (eg peroxide, trialkylaluminum, lithium halide,
A nickel-based catalyst) may be used. As the hydrogenation catalyst, noble metals such as palladium and platinum are silica,
A catalyst supported on diatomaceous earth or the like, or a catalyst composed of a titanate and an organometallic 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 synthetic resin type and natural resin type. Synthetic resin type includes aliphatic type, aromatic hydrocarbon resin type, alicyclic saturated hydrocarbon resin type, and copolymer type. The 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 resistance, transparency and rigidity. Further, 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.
Since it exceeds ppm, it does not comply with the Ministry of Health and Welfare Notification No. 20.

The method for producing the polypropylene-based sheet of the present invention is not particularly limited, but extrusion molding is suitable, and other resin layers may be provided on both sides of the sheet as long as the performance is not impaired. In addition, in the present invention, additives such as stabilizers, antistatic agents, ultraviolet absorbers, antioxidants, lubricants, fillers, dyes, pigments, neutralizing agents, if necessary, within a range that does not impair the basic properties, Slip (anti-blocking agent) or the like may be added. The total thickness of the sheet of the present invention is not particularly limited, but is 0.2 to
The thickness is in the range of 0.5 mm, and particularly the range of 0.25 to 0.4 mm is suitable as the thickness of the PTP sheet.

[0012]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples and the present invention is not limited thereto. The compounds shown in Table 1 and Table 2 were blended, polypropylene resin was extruded using an extruder having a screw diameter of 65 mm, a metal cooling roll at 60 ° C. and a metal touch roll were produced using a single-layer die. Sheeting was performed by using, and the surface was mirror-finished. The thickness of the sheet was set to 300 μm. The evaluation results of the examples and comparative examples of the present invention are shown below in Tables 3, 4, and 5.

Raw materials used in Examples and Comparative Examples Propylene homopolymer (homopolypropylene) HP-1 Chisso Polypro HT-6004 manufactured by Chisso Corporation (crystal nucleating agent content 0.3 wt%) HP-2 Mitsui Noblen JS-G manufactured by Mitsui Toatsu Chemicals, Inc. (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 Dynaron 1910P manufactured by Nippon Synthetic Rubber Co., Ltd. (styrene content 30 wt%) HSBR-2 Dynaron 1320P manufactured by Nippon Synthetic Rubber Co., Ltd. (styrene Hydrogenated styrene-isoprene copolymer SEPS-3 Hybler HVS-3 Kuraray Co., Ltd. (styrene content 30 wt%)-Petroleum resin P-1 Alcon P125 Arakawa Chemical Industry Co., Ltd. (fat) Saturated aromatic hydrocarbon compound) ・ Crystal Nucleating agent N-1 gelol 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-1 5 P-1 5 5 1 8 5 5 N-1 0.3 Table 2 Comparative Example 1 2 3 4 5 6 7 8 9 10 HP-1 85 40 90 80 75 65 72 60 70 HP-2 70 EPR-1 5 50 20 20 20 20 20 20 EPR-3 10 HSBR-1 5 5 5 5 5 5 3 15 5 HSBR-2 5 P-1 5 5 5 5 10 5 5 5 5

Each evaluation method is as follows. -Evaluation of rigidity Olsen type flexural rigidity was measured according to JIS-K-7106. -Evaluation of impact resistance DuPont impact value It measured according to JIS-K-7221. -Evaluation of transparency JIS-K- for light transmittance, haze, and internal haze.
Measured according to 6714. -Evaluation of n-heptane extraction It measured according to Ministry of Health and Welfare notification No. 20.・ Evaluation of moldability CB blister pack molding machine FB
The number of shots was fixed to 80 shots / minute using P-M2, 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-assisted pressure molding using a mold having a pocket shape having a bottom of 10 mmφ, an upper portion of 9 mmφ, a depth of 4.1 mm, and one shot of 10 pockets on two sides. The moldability was evaluated by the molding temperature range. For the molding temperature range, the molding temperature range was determined by comprehensive evaluation of the mold followability with respect to the mold, the appearance unevenness of the top of the pocket, and the thickness of the top. The mold followability and the unevenness of the appearance of the top were visually evaluated by sensory evaluation, and the thickness of the top was determined by measurement with a dial gauge.

Evaluation of curl Among the above conditions, molding was carried out under conditions showing good moldability, the contents were not filled and the aluminum foil was sealed at 180 ° C., 130
After putting a slitter at ℃, width 37mm, length 94m
The molded product punched out at m and a corner of 5 mmR was placed on a flat surface, and the warpage of the molded product after 10 minutes of punching was measured. With respect to the 6 molded products, 6 positions beside each molding pocket were measured, and an average value was obtained for evaluation. As the aluminum foil, a hard aluminum foil having a thickness of 20 μm coated with maleated polypropylene of 5 μm was used.・ Evaluation of moisture resistance After vacuum forming a sheet into a cup and filling it with silica gel,
Seal with aluminum foil, store in a thermo-hygrostat adjusted to 40 ° C, 90% RH for 10 days, and store 1 m ² , 24
The weight change per unit time was obtained and evaluated.

Table 3 Actual test items (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 ℃ 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 (℃) 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 ℃ 9.9 15.0 14.0 17.8 12.3 (kgf ・ cm)- 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 (℃) 1 12 0 8 5 Curl (mm) 2.0 3.5 3.2 3.6 2.5 n-heptane extraction (ppm) 11 148 35 160 1

Table 5 Comparative 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 Moldability (℃) 8 7 7 8 9 Curl (mm) 2.2 2.8 1.9 2.9 4.5 n-heptane extraction (ppm) 178 51 159 56 118

Evaluation Results All of the examples of the present invention 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,
Since it is possible to obtain a sheet that is excellent in transparency, moldability, and impact resistance and that complies with the Ministry of Health and Welfare Notification No. 20, it is possible to greatly suppress curling after aluminum sealing compared to conventional polypropylene-based sheets. Suitable as a polypropylene-based sheet for automobiles.

Claims (3)

[Claims] 1. A polypropylene homopolymer having a crystal nucleating agent content of 0.002 to 0.3% by weight, 57 to 84% by weight, and an ethylene-propylene random copolymer having 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, which comprises 5% by weight and a thermoplastic elastomer of 5-10% by weight. 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-based sheet according to claim 1, 3. The polypropylene-based sheet according to claim 1, wherein the petroleum resin is an alicyclic saturated hydrocarbon resin.