JP3037558B2 - Multi-layer polypropylene sheet for PTP packaging - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art PTP packaging is used for packaging pharmaceuticals, foods, and the like. The contents are stored in pockets formed by molding a plastic sheet, and aluminum foil coated with an adhesive is heat-sealed like a lid to package. This is a packaging form in which the aluminum foil is pierced by pushing the sheet forming portion with a finger to take out the contents. Conventionally, polyvinyl chloride resin has been mainly used as a plastic sheet for PTP packaging in terms of transparency, moldability, rigidity, cost, and the like. However, when the content is hygroscopic, polyvinyl chloride resin is inferior in moisture-proof property. Therefore, polyvinyl chloride resin has been used for coating. However, these materials are expensive and have a problem in cost. In recent years, polyvinyl chloride resin and polyvinylidene chloride resin have been shunned due to the generation of chlorine-containing gas during incineration due to environmental problems.Therefore, with the recent improvements in molding machines, molding was difficult before. Polypropylene sheets have been used in various applications due to their attention to moisture resistance, low cost, and easy processing, and they have also been used for PTP packaging. Due to the large expansion, the shrinkage after the aluminum sealing was large and the product was curled, causing a problem in appearance or compatibility with an automatic packaging line. Attempts have been made to increase the crystallinity of polypropylene in order to improve curl, and methods such as using a crystallization agent, gradually cooling during sheeting, and further annealing the sheet have been used. Although the curl was improved by this, on the other hand, the moldability and transparency of the sheet became extremely poor,
It was not one that could withstand actual use. In order to improve these drawbacks and further improve the rigidity of the sheet, it is conceivable to add a petroleum resin, a nucleating agent, etc. to the polypropylene resin single-layer polypropylene sheet. The sheet has poor oil resistance and n
-There was a problem that the petroleum resin was eluted in the elution test with heptane. In addition, those to which only a petroleum resin is added are inferior in impact resistance and do not endure practical use, and in order to supplement the impact resistance, if only a rubber component is added, the rigidity of the sheet itself is reduced and is not endurable. Was. A certain tension is applied to the PTP molding machine when filling tablets or capsules, but if the rigidity of the sheet is low, the filling becomes insufficient. Also, if the rigidity of the sheet is low, the curl after punching becomes large, and the molded product itself becomes soft, which is a problem in adapting the automatic packaging line.

[0003]

SUMMARY OF THE INVENTION As a result of intensive studies to solve the above-mentioned problems, the present invention has improved the rigidity of a sheet by adding a nucleating agent and a petroleum resin to polypropylene, and improved the rigidity. It has been found that a rubber component having a ratio of not deteriorating is sufficiently effective in impact resistance, and that the n-
The product is completed by heptane extraction and is excellent in transparency, moldability, rigidity, impact resistance, small curl after aluminum sealing, and excellent oil resistance, and is suitable for elution test with n-heptane etc. It is an object to provide a multi-layer polypropylene sheet for PTP packaging without problems.

[0004]

According to the present invention, there is provided a mixture comprising 70 to 90% by weight of a polypropylene homopolymer and 30 to 10% by weight of an ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight. The sealing layer (C) is composed of 40 to 90% by weight of a polypropylene homopolymer and 60 to 10% by weight of an ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight, and the intermediate layer (B) is composed of 30 to 70% of a polypropylene homopolymer. A mixture of 10 to 50% by weight of an ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight, a petroleum resin of 3 to 20% by weight, and a rubber component of 5 to 20% by weight; , A nucleating agent for 100 parts by weight of the polypropylene mixture of each of the intermediate layer (B) and the sealing layer (C).
0.5 to 0.3 parts by weight are added, and the thickness ratio of the outer layer (A) and (C) is 10 to 30% each, and the thickness ratio of the intermediate layer (B) is 80 to 40%. It is a multilayer polypropylene sheet.

The polypropylene of the outer layer (A) used in the present invention comprises 70 to 90% by weight of a polypropylene homopolymer.
And a nucleating agent in an amount of 0.05 to 0.3 parts by weight per 100 parts by weight of a mixture of 30 to 10% by weight of an ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight. When the proportion of the polypropylene homopolymer is 70% by weight or less, the curl increases, and when the proportion is 90% by weight or more, the moldability deteriorates. If no crystal nucleating agent is added, the rigidity is reduced and there is a practical problem. The polypropylene of the sealing layer (C) used in the present invention is based on 100 parts by weight of a mixture of 40 to 90% by weight of a polypropylene homopolymer and 60 to 10% by weight of an ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight. A substance to which 0.05 to 0.3 part by weight of a crystal nucleating agent is added is used. When the proportion of the ethylene propylene copolymer is 10% by weight or less or 60% by weight or more, the moldability deteriorates. Known nucleating agents are used, for example, sorbitol, dicarboxylic acid, metal salts of monocarboxylic acids, metal salts of phosphoric acid, and the like.

As the polypropylene of the intermediate layer (B), 30 to 70% by weight of a polypropylene homopolymer, 10 to 50% by weight of an ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight, 3 to 20% by weight of a petroleum resin, A composition is used in which 0.05 to 0.3 part by weight of a nucleating agent is added to 100 parts by weight of a mixture of 5 to 20% by weight of a rubber component. In order to improve the moisture resistance and rigidity, the mixing ratio of the polypropylene homopolymer may be increased. However, when the mixing ratio of the polypropylene homopolymer exceeds 70% by weight or more, the moldability deteriorates and is 30% by weight or less. And the moisture resistance and rigidity are inferior. The petroleum resin is added to improve transparency, moldability, moisture resistance, and rigidity, and is added in an amount of 3 to 20% by weight, preferably 6 to 18% by weight. When the addition amount of the petroleum resin is 3% by weight or less, there is no effect on the improvement of transparency, moldability, moisture-proof property and rigidity.
If the content is more than 10% by weight, the impact resistance is deteriorated and the material cannot be put to practical use. Known petroleum resins are used, for example, aromatic hydrocarbon resins, terpene resins, aliphatic saturated carbon resins, hydrogenated cyclopentadiene-based aliphatics, and the like.

[0007] The rubber component is added to improve the impact resistance, and is added in an amount of 5 to 20% by weight. If the amount is less than 5% by weight, the impact resistance is poor and the material cannot be put to practical use. If the amount is more than 20% by weight, the rigidity is reduced and a practical problem occurs. The rubber component used in the present invention is a natural or synthetic polymer material which is an elastic body in a room, and specific examples thereof include natural rubber, butadiene polymer, butadiene-styrene copolymer (random copolymer, block copolymer). Copolymer, graft copolymer, etc.), isoprene polymer, chlorobutadiene polymer, butadiene-acrylonitrile copolymer, isobutylene polymer, isobutylene-butadiene copolymer, isobutylene-isoprene copolymer, acrylic acid Ester copolymer, ethylene-propylene copolymer, ethylene-
Examples include propylene-diene copolymer, thiolol rubber, multi-flow rubber, polyurethane rubber, polyether rubber (for example, polypropylene oxide), epichlorohydrin rubber, and the like. Further, (co) polymers obtained by hydrogenating these rubber substances, for example, hydrogenated styrene-butadiene-
Styrene copolymer (SEBS), hydrogenated styrene-isoprene copolymer (SEP, SEPS) and the like may be used. These rubber materials can be produced by any method (eg, emulsion polymerization, solution polymerization), any catalyst (eg, peroxide,
Trialkylaluminum, lithium halide, nickel-based catalysts). Examples of hydrogenation catalysts include catalysts in which noble metals such as palladium and platinum are supported on silica, carbon, diatomaceous earth, titanium compounds and organic compounds. A catalyst composed of a metal compound (lithium, aluminum, etc.) is used.

[0008] The polypropylene used for the outer layer (A), the intermediate layer (B) and the sealing layer (C) may, if necessary,
Stabilizers Antioxidants, antistatic agents, slip agents and the like may be added. The method for producing the multilayer sheet of the present invention is not particularly limited, and a coextrusion method, an extrusion lamination method, a dry lamination method, or the like is used. The ratio of the thickness of each layer is in the range of 10 to 30% for the outer layers (A) and (C), and 80 to 40% for the intermediate layer (B). In particular, the outer layer (A) is 15%, and the intermediate layer (B) is 10%. 70% and the seal layer (C) are preferably 15%. When the thickness ratio of the outer layer (A) and the seal layer (C) is 10% or less, there is a problem of dissolution of the petroleum resin in the intermediate layer (B) in a dissolution test with n-heptane, and conversely, exceeds 30%. In addition, impact resistance and moldability deteriorate.

[0009]

【Example】

(Examples 1 to 6, Comparative Examples 1 to 3) A (screw diameter 50
mm), B (screw diameter 50 mm), C (screw diameter 50
mm) Three types of polypropylene resin were extruded using three extruders, guided to a multilayer die, and laminated with a co-extrusion method. A chill roll cooled in water [in Examples 1 and 4, a chill roll temperature of 30 ° C. Examples 2, 3, 5 and 6
Then, cooling was performed through a chill roll temperature of 40 ° C., and in Comparative Examples 1, 2, and 3, a chill roll temperature of 60 ° C.], and a multilayer sheet having a layer configuration shown in Table 1, Table 2, or Table 3 was produced. (Comparative Example 4) A polypropylene resin melt-extruded using an extruder having a screw diameter of 90 mm (resin resin P5)
Is cooled with water (chill roll temperature 60 ° C)
And cooled and taken off to produce a single-layer sheet having a thickness of 0.3 mm. Tables 4 and 5 show the evaluation results of the sheets obtained above.
Shown in

Each evaluation was carried out by the following method. Haze (JIS-K-7015) as the transparency of the sheet
Was evaluated. -Regarding oil resistance, n-
In the heptane dissolution test, those with 150 ppm or less were evaluated as acceptable (合格), and those with 150 ppm or more were evaluated as unacceptable (x). -Impact resistance is measured by DuPont impact test (JIS-K-721)
1) was evaluated. -Rigidity was evaluated by Olsen bending rigidity (JIS-K-7106). The moldability was measured using a FBP-M2 blister pack packaging machine manufactured by CK Corporation at a plug temperature of 120 ° C., a seal temperature of 200 ° C., and a machine speed of 3.0 m / min. Molding was performed by a plug pneumatic method using a mold having a pocket shape of 10 mm at the bottom, 9 mm at the top, 4.1 mm in depth, and 10 pockets per shot. The evaluation was based on the inner volume of the molding pocket as the degree of mold determination, and a relative value was defined as 100% when a 250 μm polyvinyl chloride resin sheet was molded with the same mold. The temperature of the heating platen temperature when the mold degree is 90% or more is described.・ The curl was evaluated under the above conditions, and after sealing with aluminum foil without filling the contents, the molded product was placed on a flat surface in a product form punched into a width of 37 mm, a length of 94 mm, and a corner of 5 mmR. Was measured. The ten molded products were measured at ten locations beside each molding pocket, and the average value was determined for evaluation. * If the curl after 10 minutes is less than 3.0 mm *: 3.0 mm or more and less than 3.5 mm
3.5 mm or more and less than 4.0 mm, × 4.0 mm or more ×
And

The types of resins used are as follows. * P with NA P1: Polypropylene homopolymer (MI
= 2.2) Crystal nucleating agent 0.2% added * E containing NA P2: Polypropylene homopolymer (MI
= 7.0) Crystal nucleating agent 0.2% added * E containing NA P3: Polypropylene homopolymer (MI
= 3.0) Crystal nucleating agent 0.2% added Petroleum resin 8.0% added * HO containing NA P4: Polypropylene homopolymer (MI
= 2.3) Crystal nucleating agent 0.2% added * Ho P5: Polypropylene homopolymer (MI
= 2.0) Petroleum resin 8.0% added * La P1: Polypropylene random copolymer (MI = 7.0) * La P2: Polypropylene random copolymer (MI = 1.5) * La P3: Polypropylene random copolymer (MI = 2.6) * Rubber 1: Hydrogenated styrene-butadiene rubber copolymer (styrene content 30%) * Rubber 2: Hydrogenated styrene-butadiene rubber copolymer (styrene content 10%) * Petroleum resin: alicyclic saturation Hydrocarbon resin

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

[0015]

[Table 4]

[0016]

[Table 5]

[0017]

According to the present invention, PTP which is excellent in transparency, transparency, moldability, rigidity, impact resistance, curl after aluminum sealing, and has excellent oil resistance and has no problem in dissolution test with n-heptane or the like. A multilayer polypropylene sheet for packaging can be obtained.

Claims (3)

(57) [Claims] 1. A mixture wherein the outer layer (A) comprises 70 to 90% by weight of a polypropylene homopolymer and 30 to 10% by weight of an ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight, and the sealing layer (C) comprises a polypropylene. 40 to 90% by weight of homopolymer and ethylene ratio of 0.1 to 5.0
60 to 10% by weight of ethylene propylene copolymer, and the intermediate layer (B) is made of polypropylene homopolymer 30 to
70% by weight, 10 to 50% by weight of ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight, petroleum resin 3
A multilayer polypropylene sheet for PTP packaging having a three-layer structure, comprising a mixture of -20% by weight and a rubber component of 5-20% by weight. 2. A composition in which 0.05 to 0.3 part by weight of a nucleating agent is added to 100 parts by weight of each of the polypropylene mixture of the outer layer (A), the intermediate layer (B) and the sealing layer (C). The multi-layer polypropylene sheet for PTP packaging according to claim 1, comprising a product. 3. The thickness ratio of the outer layers (A) and (C) is 10
-30% and the thickness ratio of the intermediate layer (B) is 80-40%
The multilayer polypropylene sheet for PTP packaging according to claim 1 or 2, wherein