JPH07186346A - Ptp multilayered polypropylene sheet - Google Patents

Abstract

PURPOSE:To provide a PTP polypropylene sheet excellent in transparency and moldability, enabling aluminum sealing, reduced in curling after aluminum sealing and fitted to an automatic accumulation line. CONSTITUTION:A multilayered polypropylene sheet has three-layered constitution consisting of a outer layer (A) formed from a compsn. prepared by adding 0.05-0.3wt.% of a crystal nucleus agent to a polypropylene homopolymer, an intermediate layer (B) formed from a compsn. prepared by adding 5-20wt.% of a petroleum resin to a polypropylene homopolymer or a compsn. prepared by adding 0.05-0.3 wt.% of a crystal nucleus agent thereto and a seal layer (C) formed from a polypropylene homopolymer, a compsn. prepared by adding 0.05-0.3wt.% of a crystal nucleus agent to a polypropylene homopolymer or an ethylene/propylene copolymer with ethylene content of 0.1-5.0wt.% and the thickness ratio of the outer layer (A) is 10-50% of the total thickness of the sheet and the bending modulus thereof is 12000fkg/cm<2> or more.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art What is PTP packaging? For packaging pharmaceuticals, foods, etc., the contents are stored in a pocket made by molding a plastic sheet, and an aluminum foil coated with an adhesive is heat-sealed like a lid for packaging. It is in the packaging form, and the contents are taken out from the aluminum foil by pushing the sheet forming part with a finger and used. Conventionally, polyvinyl chloride resin has been mainly used as a plastic sheet for PTP packaging because of its transparency, moldability, rigidity and cost. However, when the content has hygroscopicity, the polyvinyl chloride resin has a moisture-proof property, and therefore, a polyvinylidene chloride resin has been coated to deal with it, but these are expensive and there is a problem in terms of 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, and therefore, due to recent improvements in molding machines, molding was difficult before. The polypropylene sheet has been used for various purposes due to its moisture proof, low cost and easy processability, and it was also used for PTP packaging. Due to the large expansion, the product shrinks after aluminum sealing and the product curls, causing problems in appearance and compatibility with automatic packaging lines.
Attempts have been made to increase the crystallinity of polypropylene in order to improve the curl, and methods such as using a crystallization agent, gradually cooling during sheeting, and further annealing the sheet have been carried out. Although the curl was improved by this, on the other hand, the formability and the transparency of the sheet were remarkably deteriorated, and it was not usable in actual use. Further, in the case of performing aluminum sealing, if the sealing is performed at a high temperature, the curl becomes large and a problem is likely to occur, and it is desired to perform the aluminum sealing at a low temperature.

[0003]

DISCLOSURE OF THE INVENTION As a result of earnest research to solve the above-mentioned problems, the present invention has a sufficient curling effect even with a polypropylene layer having a thickness ratio of such a degree that moldability and transparency are not deteriorated. The PT that has been completed by creating a multi-layered sheet with 3 layers has excellent transparency and moldability, and can be aluminum-sealed at low temperature.
A polypropylene sheet for P packaging is provided.

[0004]

The present invention provides an outer layer (A) comprising a composition obtained by adding 0.05 to 0.3% by weight of a crystal nucleating agent to a polypropylene homopolymer, and a polypropylene homopolymer to a petroleum resin of 5 to 20% by weight. % Composition or an intermediate layer (B) composed of a composition containing 0.05 to 0.3% by weight of a crystal nucleating agent, a polypropylene homopolymer,
Or polypropylene homopolymer with a crystal nucleating agent of 0.05 to
Composition added with 0.3 wt% or ethylene ratio 0.1
In a multi-layer polypropylene sheet having a three-layer structure comprising a seal layer (C) made of ethylene-propylene copolymer of about 5.0 wt%, the thickness ratio of the outer layer (A) is 1 of the total thickness.
0 to 50% and flexural modulus 12000 fkg / cm
^The present invention relates to a multi-layer polypropylene sheet having a number of ² or more.

In the present invention, the flexural modulus of the polypropylene of the outer layer (A) is 1200 in order to obtain the curl prevention effect regardless of which polypropylene is used as the inner layer.
Must be above 0 kgf / cm ² . Outer layer (A)
When an ethylene propylene copolymer having an ethylene ratio of 5.0% or more is used as the polypropylene, it becomes difficult to obtain a desired flexural modulus, and a polypropylene homopolymer is used as the polypropylene in the outer layer (A). The desired flexural modulus may not be obtained under some conditions, and in that case, a crystal nucleating agent may be added to obtain the desired flexural modulus. As the crystal nucleating agent, known substances are used, and sorbitol type, dicarboxylic acid type, metal salt of monocarboxylic acid, metal salt of phosphoric acid and the like are generally used.

A polypropylene homopolymer is used as the polypropylene of the intermediate layer (B). In this case,
In order not to significantly deteriorate moldability and transparency, for example, 5
Means such as cooling with a chill roll through which cooling water at 0 ° C. or lower is passed. Further, in order to obtain moisture resistance and low curl property, petroleum resin 5 to 20% by weight, preferably 14 to 17%
% Is added. If the amount of the petroleum resin added is 5% by weight or less, there is no effect on the moisture resistance and the low curl property, and if it exceeds 20% by weight, the impact resistance deteriorates and it cannot be put to practical use. Known petroleum resins are used, and aromatic hydrocarbon resin-based, terpene resin-based, aliphatic saturated carbon resin-based,
Hydrogenated cyclopentadiene-based aliphatic compounds are common.

The seal layer (C) in the present invention comprises polypropylene homopolymer, a composition obtained by adding 0.05 to 0.3% by weight of a crystal nucleating agent to polypropylene homopolymer, or an ethylene ratio of 0.1 to 5.0. A weight percentage of ethylene propylene copolymer is used. When low temperature sealability is important, ethylene propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight can be used as polypropylene for the seal layer. If necessary, stabilizers such as stabilizers, antistatic agents, slip agents and the like can be added to the polypropylene used for the outer layer, the inner layer and the intermediate layer. The method for producing the multilayer sheet of the present invention is not particularly limited, and a coextrusion method, an extrusion laminating method, a dry laminating method or the like can be used. Regarding the thickness ratio, the outer layer (A) is 10 to 50% of the total thickness, the intermediate layer (B) is 70 to 40% of the total thickness, and the seal layer (C) is 30 to 10% of the total thickness. It is preferable that (A) is 30%, the intermediate layer (B) is 50%, and the sealing layer (C) is 20%.

[0008]

[Example] A (screw diameter 50 mm), B (screw diameter 50 mm), C (screw diameter 50 mm) Using three extruders, three types of polypropylene resin were extruded, then introduced into a multi-layer die and coextruded. The laminated resin was passed through a chill roll cooled with water, cooled, and collected to prepare multilayer sheets of Examples 1 to 4. In addition, the polypropylene resin melt extruded using an extruder with a screw diameter of 90 mm is introduced into a die and extruded,
It was passed through a chill roll cooled with water and cooled, and then taken up to prepare single-layer sheets of Comparative Examples 1 and 2. Table 1 shows the type of polypropylene resin used, the chill roll temperature, and the evaluation results of the obtained sheet.

The polypropylene used is as follows. * NA-containing homo PP1 [NP1] polypropylene homopolymer (MI = 2.2, crystal nucleating agent 0.2% added) [Chisso Corporation Chisso Polypro HT6004] * NA-containing homo PP2 [NP2] polypropylene homopolymer 80.0 Weight% (MI = 3.0, Crystal Nucleating Agent 0.2% Added, Petroleum Resin 8.0% Added) [Mitsui Toatsu Chemicals, Inc. Mitsui Noblen JS-4793] Petroleum Resin-PP Masterbatch 20.0 wt. % [Arakawa Chemical Co., Ltd. MB1004] * NA-containing homo PP3 [NP3] Polypropylene homopolymer (MI = 2.3, crystal nucleating agent 0.2% added) [Chisso Corporation Chisso Polypro HT0004] * NA-containing homo PP4 [NP4] Polypropylene homopolymer (MI = 4.0, crystal nucleating agent 0.2% added) [Chisso PolyPro HT0020] * Homo PP1 [PP1] polypropylene homopolymer 80.0% by weight (MI = 3.0, petroleum resin 8.0% added) [Mitsui Toatsu Chemicals, Inc. Mitsui Noblen JS-2871] Petroleum resin masterbatch 20.0 Weight% [Arakawa Chemical Co., Ltd. MB1004] * Homo PP2 [PP2] Polypropylene homopolymer (MI = 3.0, 8% petroleum resin added) [Mitsui Toatsu Chemical Co., Ltd. Mitsui Noblen JS-2871] * Random PP1 [ RP1] 5% ethylene content ethylene polypropylene copolymer (MI = 2.6) [Sumitomo Chemical Co., Ltd. Sumitomo Noblen WF467L] * Random PP2 [RP2] 5% ethylene content polypropylene random copolymer (MI = 1.5) ( Mitsui Toatsu Chemicals Mitsui Noblen MJS-G)

Each evaluation method is as follows. The transparency of the sheet depends on the haze (ASTM-D-1003). Moldability and curl are evaluated by CKD FBP-M2
Using a blister pack packaging machine, the molding temperature was 145 ° C., the sealing temperature was 200 ° C., and the machine speed was 3.0 m / min. As the aluminum foil, a hard aluminum foil having a thickness of 20 μm coated with maleic polypropylene of 5 μm was used. (1) Formability The pocket shape is 10 mm at the bottom, 9 mm at the top, and a depth of 4.1.
mm, one shot, 10 pockets, two-sided mold was used, and molding was performed by a plug pressure air method. The evaluation was carried out by evaluating the inner volume of the molding pocket as the degree of mold determination, and using a 250 μm polyvinyl chloride resin sheet molded in the same mold as 100%, it was expressed as a relative value. A, 7 with 90% or more of type determination
B of 0% to less than 90%, C of 50% to less than 70%, and D of less than 50%. (2) Curl After molding under the above conditions and heat sealing with aluminum foil without filling the contents, width 37 mm length 94 mm, corner 5 mm
In the product form punched into R, the molded product was placed on a flat surface and the warp in the width direction was measured. Ten molded articles were measured at 10 locations beside each molding pocket, and an average value was obtained for evaluation. A curl after 10 minutes is less than 3.0 mm, and a curl after 3.0 mm is less than 3.5 mm.
A value of 3.5 mm or more and less than 4.0 mm was evaluated as Δ, and a value of 4.0 mm or more was evaluated as x. (3) Aluminum sealing temperature Without molding the contents, the sealing temperature is reduced to 200 to 110 ° C in increments of 10 and the sealing condition with aluminum foil is evaluated to make sealing (aluminum foil When peeled off, the aluminum was peeled off, but the sheet surface was white).

[0011]

[0012]

According to the present invention, it is possible to obtain a polypropylene sheet having good moldability and having a small curl after aluminum sealing. In particular, the PTP continuous molding machine performs molding and sealing at high speed, and can be used in an automatic stacking line without causing any trouble.

Claims (1)

[Claims] 1. An outer layer (A) comprising a composition obtained by adding 0.05 to 0.3% by weight of a crystal nucleating agent to polypropylene homopolymer, and polypropylene homopolymer to petroleum resin 5-2.
0% by weight of the composition added thereto or a crystal nucleating agent 0.05%
An intermediate layer (B) composed of a composition added by 0.3 wt%
From a polypropylene homopolymer, or a composition obtained by adding 0.05 to 0.3% by weight of a crystal nucleating agent to a polypropylene homopolymer, or a sealing layer (C) made of an ethylene-propylene copolymer having an ethylene ratio of 0.1 to 5.0% by weight. A multilayer polypropylene sheet having the following three-layer structure, wherein the outer layer (A) has a thickness ratio of 10 to 50% of the total thickness, and a flexural modulus of 12000 fkg / cm ² or more.