JP7255738B2 - Polyolefin-based sheet, bottom material for press-through package packaging and press-through package packaging material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyolefin sheet excellent in secondary workability, moisture resistance, transparency and splittability, and a bottom material for press-through package packaging and a press-through package packaging material using the same.

2. Description of the Related Art In the field of packaging pharmaceuticals, foods, and the like, PTP (press through package) packaging is implemented for packaging solid agents such as capsules and tablets, granular foods, and the like. In the field of food packaging, blister packaging, which is similar to PTP packaging, is often used for packaging foods.

PTP packaging is, for example, a transparent sheet that is subjected to air pressure molding, vacuum molding, etc. to form a pocket for storing a solid agent such as a capsule. It is a package in which foils and films made of materials that can be easily torn by hand and easily opened are laminated and integrated as a cover material. According to the PTP packaging, the solid agent, food, etc. stored in the pocket of the transparent sheet can be directly checked with the naked eye before opening. The contents can be easily taken out by tearing.

A blister package is a sheet formed by vacuum forming or the like to form a pocket portion according to the shape of food, etc., and after containing the contents of food, etc. in this pocket portion, it is wrapped with heat-sealable coated paper or film. It is a form of packaging that is sealed.

Polyvinyl chloride (hereinafter also referred to as "PVC") has been conventionally used as a raw material for sheets used in PTP packaging and blister packaging because it has good thermoformability, rigidity at room temperature, impact resistance, and transparency. has been used from However, depending on the combustion method, PVC generates hydrogen chloride gas, degrading the combustion furnace and causing environmental pollution. From the standpoint of long-term storage, there has been a demand for a material that can replace PVC.

Therefore, polypropylene-based resin (hereinafter sometimes referred to as "PP") is generally used as a substitute material for PVC. For example, Patent Literature 1 proposes a resin sheet made of PP and hydrogenated petroleum resin and suitable for PTP packaging with good transparency and moisture resistance.

However, although PP is superior in moisture resistance to PVC, further improvement in moisture resistance is demanded in recent years. Therefore, "amorphous polyolefin", which not only has excellent moisture resistance but also has transparency and viscoelastic behavior similar to PVC, is attracting attention as one of the alternative materials for PVC and PP. Patent Document 2 proposes PTP packaging using polyethylene, a crystal nucleating agent, and a petroleum resin.

Japanese Patent Publication No. 6-99604 JP 2012-131933 A

Since the above PTP packaging is used for carrying or taking medicine in small portions, the PTP packaging is required to have a splitting property so that it can be easily divided by hand after slitting the PTP packaging. The polyethylene-based sheet disclosed in Patent Document 2 has improved transparency and moisture resistance, but has a problem of poor splittability (hand tearability) because polyethylene is flexible and stretchable.

Therefore, in view of such problems of the prior art, the object of the present invention is to provide a new polyolefin sheet having sufficient transparency and moisture resistance and excellent splittability, and a PTP packaging using the same. To provide a bottom material and a PTP packaging material.

As a result of intensive studies to solve the above problems, the present inventors have found that a high-density polyethylene resin, a crystal nucleating agent, a specific thermoplastic resin, and a thermoplastic resin that has a high storage modulus and is incompatible with a polyethylene resin The present inventors have found that the above problems can be solved by forming a sheet from a thermoplastic resin composition containing and, and have completed the present invention.

That is, the present invention has a layer (I) formed from a thermoplastic resin composition containing the following (A), (B), (C) and (D), A polyolefin sheet wherein (C) is 3% by mass or more and 30% by mass or less and (D) is 3% by mass or more and 60% by mass or less when the plastic resin composition is 100% by mass. is.
(A) Polyethylene resins having a density of 0.935 g/cm ³ or more as measured according to JIS K7112 (B) Crystal nucleating agents (C) Petroleum resins, terpene resins, coumarone-indene resins, rosin resins, and their At least one thermoplastic resin selected from the group consisting of hydrogenated derivatives (D) A thermoplastic resin having a storage modulus (E′) at 24° C. of 1000 MPa or more and incompatible with (A)

According to the present invention, the polyolefin-based sheet of the present invention is excellent in splittability, moisture resistance and transparency, and therefore can be suitably used for various types of packaging, and is particularly suitable for PTP packaging bottom materials. can be done.

It is a figure for demonstrating the PTP molding used for evaluation of the divisibility of the Example mentioned later.

A polyolefin sheet will be described below as one example of embodiments of the present invention. However, the scope of the present invention is not limited to the embodiments described below.

In the present invention, when described as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, "X or more and Y or less", "preferably larger than X" and "preferably Y It includes the meaning of "less than".

<About layer (I)>
The polyolefin-based sheet of the present invention has a layer (I) formed from a thermoplastic resin composition containing the following (A), (B), (C) and (D).
(A) Polyethylene resins having a density of 0.935 g/cm ³ or more as measured according to JIS K7112 (B) Crystal nucleating agents (C) Petroleum resins, terpene resins, coumarone-indene resins, rosin resins, and their At least one thermoplastic resin selected from the group consisting of hydrogenated derivatives (D) A thermoplastic resin having a storage elastic modulus (E') at 24 ° C. of 1000 MPa or more and incompatible with the above (A) Layer ( The thermoplastic resin composition forming I) will be described.

[Polyethylene resin (A)]
The polyethylene resin (A) used in the present invention has a density of 0.935 g/cm ³ or more as measured according to JIS K7112. A more preferable range of density is 0.940 g/cm ³ or more, and a further preferable range is 0.945 g/cm ³ or more. When the density is within the above range, a sheet having high moisture resistance and chemical resistance can be provided.

The polyethylene-based resin (A) may be polyethylene that is an ethylene homopolymer, or may be a polyethylene copolymer that is a copolymer of ethylene and a monomer component other than ethylene. A mixture of these may also be used as the polyethylene-based resin (A).

Examples of monomer components other than ethylene include α-olefin monomers and non-olefin monomers having functional groups, among which α-olefin monomers are preferred.

Examples of the α-olefin monomer include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 4- methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4, 4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene and the like. be done. These may be used alone or in combination of two or more. Among them, propylene, 1-butene, 1-hexene, and 1-octene are preferable from the viewpoint of industrial availability, characteristics, economy, and the like.

When the α-olefin monomer is used as a copolymerization component, the total ratio of the α-olefin monomer in the polyethylene copolymer is preferably 0.1 to 4.0% by mass, more preferably 0.3. to 3.5% by mass, particularly preferably 0.5 to 3.0% by mass. If the ratio of the α-olefin monomer is within such a range, the moisture resistance and transparency of the polyolefin sheet can be further improved.

Among the above, the polyethylene resin (A) used in the present invention is an ethylene homopolymer, or at least one selected from the group consisting of ethylene, propylene, 1-butene, 1-hexene, and 1-octene. It is preferred to use a copolymer with an α-olefin monomer.

The method for polymerizing the polyethylene resin (A) is not particularly limited, and can be carried out by a conventionally known method, and the catalyst used for polymerization is also not particularly limited, and a conventionally known one can be used.

In addition, the melt flow rate (hereinafter also referred to as "MFR") of the polyethylene resin (A) at 190 ° C. and a load of 2.16 kg in JIS K7210 is 0.3 g / 10 minutes or more and 20 g / 10 minutes or less. is preferably 0.5 g/10 min or more and 10 g/10 min or less, and more preferably 0.8 g/10 min or more and 8.0 g/10 min or less. If the MFR is within the above range, stable film-forming properties can be obtained, and a polyolefin sheet having good mechanical properties can be obtained.

The polyethylene-based resin (A) may be a petroleum-derived polyethylene-based resin, but is preferably a bio-polyethylene-based resin from the viewpoint of environmental protection.
The "biopolyethylene-based resin" means a polyethylene-based resin obtained by chemically or biologically synthesizing a renewable biomass resource as a raw material. The above-mentioned bio-polyethylene-based resin has the characteristic that even if it is incinerated, it does not increase the concentration of carbon dioxide in the atmosphere due to the carbon neutrality of biomass.

It is preferable to use plant-derived ethylene derived from bioethanol obtained from plant raw materials as the biopolyethylene-based resin. That is, the biopolyethylene-based resin is preferably a plant-derived polyethylene-based resin.

Specific products of the polyethylene-based resin (A) include petroleum-derived polyethylene-based resins such as the "Suntech HD" series manufactured by Asahi Kasei Corporation, the "Novatec HD" series manufactured by Japan Polypropylene Corporation, and the Prime Polymer "Evolue H" series. mentioned. Further, examples of biopolyethylene-based resins include Braskem's "Green Polyethylene" series.

The content of the polyethylene resin (A) is preferably 20% by mass or more and 90% by mass or less, more preferably 25% by mass, when the resin composition forming the layer (I) is taken as 100% by mass. 80% by mass or more, and particularly preferably 30% by mass or more and 75% by mass or less. Moisture resistance can be imparted by setting the ratio of the polyethylene-based resin (A) to the above lower limit or more. Also, by setting the ratio of the polyethylene resin (A) to the upper limit or less, good splittability can be imparted.

[Crystal Nucleating Agent (B)]
The crystal nucleating agent (B) is added to improve the transparency and moisture resistance of the polyolefin sheet.

Examples of the crystal nucleating agent (B) include dibenzylidene sorbitol (DBS) compounds, 1,3-O-bis(3,4 dimethylbenzylidene) sorbitol, dialkylbenzylidene sorbitol, and compounds having at least one chlorine or bromine substituent. diacetal of sorbitol, di(methyl- or ethyl-substituted benzylidene) sorbitol, bis(3,4-dialkylbenzylidene) sorbitol having substituents forming a carbocyclic ring, aliphatic, alicyclic and aromatic carboxylic acids, dicarboxylic acids Or polybasic polycarboxylic acids, metal salt compounds of organic acids such as their anhydrides and metal salts, cyclic bis-phenol phosphates, bicyclics such as disodium bicyclo[2.2.1]heptenedicarboxylic acid formula dicarboxylic acid and salt compounds, saturated metal or organic salt compounds of bicyclic dicarboxylates such as bicyclo[2.2.1]heptane-dicarboxylate, 1,3:2,4-O-dibenzylidene -D-sorbitol, 1,3:2,4-bis-O-(m-methylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(m-ethylbenzylidene)-D-sorbitol , 1,3: 2,4-bis-O-(m-isopropylbenzylidene)-D-sorbitol, 1,3: 2,4-bis-O-(mn-propylbenzylidene)-D-sorbitol, 1 , 3: 2,4-bis-O-(mn-butylbenzylidene)-D-sorbitol, 1,3: 2,4-bis-O-(p-methylbenzylidene)-D-sorbitol, 1,3 : 2,4-bis-O-(p-ethylbenzylidene)-D-sorbitol, 1,3: 2,4-bis-O-(p-isopropylbenzylidene)-D-sorbitol, 1,3:2,4 -bis-O-(pn-propylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(pn-butylbenzylidene)-D-sorbitol, 1,3:2,4 -bis-O-(2,3-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,4-dimethylbenzylidene)-D-sorbitol, 1,3:2,4 -bis-O-(2,5-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol, 1,3:2,4 -bis-O-(3,5-dimethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,3-diethylbenzylidene)-D-sorbitol, 1,3:2,4 -bis-O-(2,4-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(2,5-diethylbenzylidene)-D-sorbitol, 1,3:2,4 -bis-O-(3,4-diethylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(3,5-diethylbenzylidene)-D-sorbitol, 1,3:2,4 -bis-O-(2,4,5-trimethylbenzylidene)-D-sorbitol, 1,3: 2,4-bis-O-(3,4,5-trimethylbenzylidene)-D-sorbitol, 1,3 : 2,4-bis-O-(2,4,5-triethylbenzylidene)-D-sorbitol, 1,3: 2,4-bis-O-(3,4,5-triethylbenzylidene)-D-sorbitol , 1,3: 2,4-bis-O-(p-methyloxycarbonylbenzylidene)-D-sorbitol, 1,3: 2,4-bis-O-(p-ethyloxycarbonylbenzylidene)-D-sorbitol , 1,3: 2,4-bis-O-(p-isopropyloxycarbonylbenzylidene)-D-sorbitol, 1,3: 2,4-bis-O-(on-propyloxycarbonylbenzylidene)-D -sorbitol, 1,3:2,4-bis-O-(o-n-butylbenzylidene)-D-sorbitol, 1,3:2,4-bis-O-(o-chlorobenzylidene)-D-sorbitol , 1,3:2,4-bis-O-(p-chlorobenzylidene)-D-sorbitol, 1,3:2,4-bis-O-[(5,6,7,8,-tetrahydro-1 -naphthalene)-1-methylene]-D-sorbitol, 1,3:2,4-bis-O-[(5,6,7,8,-tetrahydro-2-naphthalene)-1-methylene]-D- sorbitol, 1,3-O-benzylidene-2,4-O-p-methylbenzylidene-D-sorbitol, 1,3-O-p-methylbenzylidene-2,4-O-benzylidene-D-sorbitol, 1, 3-O-benzylidene-2,4-O-p-ethylbenzylidene-D-sorbitol, 1,3-O-p-ethylbenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O- benzylidene-2,4-O-p-chlorobenzylidene-D-sorbitol, 1,3-O-p-chlorobenzylidene-2,4-O-benzylidene-D-sorbitol, 1,3-O-benzylidene-2, 4-O-(2,4-dimethylbenzylidene)-D-sorbitol, 1,3-O-(2,4-dimethylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1,3-O- benzylidene-2,4-O-(3,4-dimethylbenzylidene)-D-sorbitol, 1,3-O-(3,4-dimethylbenzylidene)-2,4-O-benzylidene-D-sorbitol, 1, 3-O-p-methyl-benzylidene-2,4-O-p-ethylbenzylidene sorbitol, 1,3-p-ethyl-benzylidene-2,4-p-methylbenzylidene-D-sorbitol, 1,3-O -p-methyl-benzylidene-2,4-Op-chlorobenzylidene-D-sorbitol, 1,3-Op-chloro-benzylidene-2,4-Op-methylbenzylidene-D-sorbitol, etc. Diacetal compound, sodium 2,2'-methylene-bis-(4,6-di-tert-butylphenyl) phosphate, aluminum bis[2,2'-methylene-bis-(4-6-di-tert-butylphenyl ) phosphate], 2,2-methylenebis(4,6-di-tert-butylphenyl)sodium phosphate, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristine acids, fatty acids such as pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecanic acid, arachidic acid, behenic acid and montanic acid, fatty acid amides such as oleic acid amide, erucic acid amide, stearic acid amide and hebenic acid amide, stearin Fatty acid metal salts such as magnesium stearate, zinc stearate and calcium stearate; inorganic particles such as silica, talc, kaolin and calcium carbide; higher fatty acid esters such as glycerol and glycerin monoester; These may be used alone or in combination of two or more.
Among these, fatty acid amides such as oleic acid amide, erucic acid amide, stearic acid amide and hebenic acid amide, and fatty acid metal salts such as magnesium stearate, zinc stearate and calcium stearate are particularly preferred.

Specific products of the crystal nucleating agent (B) include, for example, "Gelol D" series manufactured by Shin Nippon Rika Co., Ltd., "ADEKA STAB" series manufactured by Asahi Denka Kogyo Co., Ltd., and "HYPERFORM HPN-20E" and "HL3" manufactured by Milliken Chemical Co., Ltd. -4", "Millad" series, "IRGACLEAR" series manufactured by BASF, "Rikemaster CN-001" and "Rikemaster CN-002" manufactured by Riken Vitamin Co., Ltd., and the like. Among these, products that are particularly effective in improving transparency include "HYPERFORM HPN-20E" and "HL3-4" manufactured by Milliken Chemical Co., Ltd., and "Rikemaster CN-001" and "Rikemaster CN-002" manufactured by Riken Vitamin. ” and the like.

The content of the crystal nucleating agent (B) is preferably 0.5% by mass or more and 4.0% by mass or less when the resin composition forming the layer (I) is taken as 100% by mass. It is preferably 1% by mass or more and 3.5% by mass or less. By setting the ratio of the crystal nucleating agent (B) to the above lower limit or more, the crystallinity of the polyolefin-based sheet can be improved, and suitable transparency and moisture resistance can be imparted. Further, by setting the ratio of the crystal nucleating agent (B) to the upper limit or less, the ratio of the additive can be minimized and an efficient effect can be expected.

[Thermoplastic resin (C)]
As the thermoplastic resin (C), at least one selected from the group consisting of petroleum resins, terpene resins, chroman-indene resins, rosin resins, and hydrogenated derivatives thereof is used. Moreover, it is preferable that the thermoplastic resin (C) is compatible with the polyethylene resin (A) and has a glass transition temperature higher than that of the polyethylene resin (A).

Examples of the petroleum resin include petroleum resins such as C5 petroleum resins, C9 petroleum resins, and C5-C9 copolymer petroleum resins; alicyclic hydrocarbon petroleum resins such as dicyclopentadiene petroleum resins; and hydrogenated derivatives of Among them, hydrogenated derivatives of C9 petroleum resins are preferred.

Examples of the terpene resin include terpene resins such as α-pinene polymer, β-pinene polymer, and dipentene polymer, and modified terpene resins such as terpene phenolic resins, styrene-modified terpene-based resins, and hydrogenated terpene-based resins. etc.

Examples of the coumarone-indene resin include thermoplastic synthetic resins obtained by purifying a fraction of tar at 160 to 180° C. and polymerizing coumarone having 8 carbon atoms and indene having 9 carbon atoms as main monomers. .

Examples of the rosin-based resin include unmodified rosins such as tall rosin, gum rosin, and wood rosin, polymerized rosins, disproportionated rosins, hydrogenated rosins, maleic acid-modified rosins, fumaric acid-modified rosins, glycerin, pentaerythritol, An esterified rosin resin modified with ethylene glycol or the like can be mentioned.

As the thermoplastic resin (C), it exhibits relatively good compatibility when mixed with the polyethylene resin (A), and from the viewpoint of further improving color tone, thermal stability, compatibility, moisture permeability resistance, etc., hydrogenation Derivatives are preferred, particularly those having a hydrogenation rate (hereinafter referred to as "hydrogenation rate") of 95% or more and substantially free of hydroxyl groups, carboxyl groups, polar groups such as halogens, or unsaturated bonds such as double bonds. , petroleum resins or terpene resins are preferred, and petroleum resins are particularly preferred.

The softening point of the thermoplastic resin (C) is preferably 80-170°C, more preferably 90-160°C, and particularly preferably 100-150°C. When the softening point of the thermoplastic resin (C) is within the above range, the thermoplastic resin (C) is easily compatible with the polyethylene resin (A), and fine fine particles are formed due to crystallization of the polyethylene resin (A). The formation of crystals is further promoted, and there is a tendency to obtain a polyolefin sheet having excellent transparency. Further, when the softening point is at least the above lower limit, blocking of raw material pellets is prevented during sheet film formation, and productivity tends to be good.

Specific examples of the thermoplastic resin (C) include, for example, the "Petrotac" series manufactured by Tosoh Corporation, the "Arcon" series manufactured by Arakawa Chemical Industries, Ltd., the "Clearon" series manufactured by Yasuhara Chemical Co., Ltd., and the "IMAVE" series manufactured by Idemitsu Petrochemical Co., Ltd. , "T-REZ" series manufactured by JXTG Energy Co., Ltd., and the like.

The content of the thermoplastic resin (C) is 3% by mass or more and 30% by mass or less, and 8% by mass or more and 27% by mass when the resin composition forming the layer (I) is 100% by mass. It is preferably 10% by mass or more and 25% by mass or less. By setting the proportion of the thermoplastic resin (C) to the above lower limit or more, the transparency and moisture resistance of the sheet are improved. Also, by setting the proportion of the thermoplastic resin (C) to the upper limit or less, good film formability and impact resistance can be maintained.

[Thermoplastic resin (D)]
It is important that the resin used for the thermoplastic resin (D) has a storage modulus (E′) at 24° C. of 1000 MPa or more and is incompatible with the polyethylene resin (A). By using such a thermoplastic resin that is incompatible with the polyethylene-based resin (A) and has a high storage elastic modulus, it is possible to impart good splittability to the polyolefin-based sheet.
Incompatible with the polyethylene resin (A) here means that the thermoplastic resin (D) is not compatible with the polyethylene resin (A). It can be confirmed by observing the cross section of the filmed polyolefin-based sheet. When the observed cross section has a sea-island structure, the thermoplastic resin (D) is incompatible with the polyethylene resin (A). In addition, the poorer the compatibility between the polyethylene resin (A) and the thermoplastic resin (D), the larger the dispersion diameter (island structure). Physical properties derived from both the resin (A) and the thermoplastic resin (D) appear independently. Therefore, the compatibility between the thermoplastic resin (D) and the polyethylene resin (A) is poor, and as the dispersion diameter (island structure) increases, the flexibility of the polyethylene resin (A) is inhibited by the thermoplastic resin (D). Therefore, the splittability of the polyolefin sheet is improved.

A more preferable range of the storage modulus (E′) is 1000 MPa or more and 50000 MPa or less, and more preferably 1400 MPa or more and 4000 MPa or less. By setting the storage modulus (E′) of the thermoplastic resin (D) within the above range, it is possible to efficiently impart splittability to the sheet while maintaining good film formability and moldability. .

The storage elastic modulus (E′) is a value at 24° C. when dynamic viscoelasticity is measured using a viscoelasticity measuring device under the following conditions.
[Measurement condition]
Vibration frequency: 10Hz
Strain: 0.1%
Heating rate: 3°C/min Measurement temperature: -50 to 200°C

At least one selected from the group consisting of propylene-based resins, ester-based resins, styrene-based resins, and cyclic olefin-based resins is preferable as the thermoplastic resin (D). By using the above resin as the thermoplastic resin (D), it is possible to impart suitable splittability to the sheet while maintaining the moisture resistance, transparency and film formability of the polyolefin sheet. Among them, propylene-based resins and cyclic olefin-based resins are preferred.

Examples of the propylene-based resin include a propylene homopolymer and a copolymer of propylene and an α-olefin such as ethylene. Among them, a copolymer of propylene and α-olefin is preferred, and a copolymer of propylene and ethylene is more preferred.

When a copolymer is used as the propylene-based resin, the proportion of propylene in the copolymer is preferably 80% or more, more preferably 90% or more, and still more preferably 97% or more. When the content of propylene in the copolymer is at least the above range, rigidity and moisture resistance necessary for sheet splittability are imparted.

Examples of the ester resin include polyethylene terephthalate resin, polypropylene terephthalate resin, polybutylene terephthalate resin, polyethylene isophthalate resin, polyethylene naphthalate resin, polybutylene naphthalate resin, polyethylene terephthalate/isophthalate copolymer resin, 1,4 - Low-crystalline or amorphous polyethylene terephthalate resins, polyethylene/neopentyl terephthalate copolymer resins, and polylactic acid resins containing 15 mol% or more and 50 mol% or less of cyclohexanedimethanol units in all glycol monomer units Typical examples include aliphatic polyester-based resins.

Examples of the styrene resin include GPPS (general purpose polystyrene), HIPS (high impact polystyrene), SEPS (styrene-ethylene-propylene-styrene copolymer), SIS (styrene-isoprene-styrene copolymer), MS (styrene-methyl methacrylate copolymer) and the like.

Examples of the cyclic polyolefin-based resin include polymers obtained by optionally hydrogenating ring-opening (co)polymers of cyclic olefins, addition (co)polymers of cyclic olefins, and mixtures of cyclic olefins and α-olefins such as ethylene and propylene. The random copolymer, the cyclic olefin ring-opening (co)polymer or the cyclic olefin ring-opening (co)polymer and hydrogenated products thereof, for example, maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, A graft copolymer modified with a modifying agent such as an unsaturated carboxylic acid such as (meth)acrylic acid or an anhydride thereof may be used. Among them, copolymers of cyclic olefins and α-olefins are preferred, and copolymers of cyclic olefins and ethylene are more preferred.

The above-mentioned "(co)polymer" is meant to include "polymer" and "copolymer", and "(meth)acrylic" is meant to include "acryl" and "methacrylic". be.

Specific examples of the thermoplastic resin (D) include "Novatec PP" series manufactured by Japan Polypro Co., Ltd., "Prime Polypro" series manufactured by Prime Polymer Co., Ltd., "SunAllomer" series manufactured by SunAllomer Co., Ltd., "Qualia" series manufactured by Sumitomo Chemical Co., Ltd. "Noblen" series, "GPPS" series manufactured by Polystyrene Japan, "HIPS" series, "TX" series manufactured by Denka, "ZEONOR" series manufactured by Nippon Zeon, "Zelath" series manufactured by Mitsubishi Chemical, " Appel" series, Polyplastics "TOPAS" series, and the like.

The content of the thermoplastic resin (D) is 3% by mass or more and 60% by mass or less, and 5% by mass or more and 50% by mass when the resin composition forming the layer (I) is 100% by mass. It is preferably 10% by mass or more and 40% by mass or less. By setting the ratio of the thermoplastic resin (D) to the above lower limit or more, the splittability of the sheet can be improved. Further, by setting the proportion of the thermoplastic resin (D) to the upper limit or less, the transparency and moisture resistance of the sheet can be maintained.

[Other additives]
Further, the thermoplastic resin composition forming the layer (I) may contain polyolefin-based resins, polystyrene-based resins, polyester-based resins other than the above (A) to (D), and Addition of resins such as polyolefin-based or polystyrene-based thermoplastic elastomers, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, antibacterial/antifungal agents, antistatic agents, lubricants, etc. agents can be added. These may be used alone or in combination of two or more.

The polyolefin-based sheet of the present invention has a layer (I) formed from a thermoplastic resin composition containing the above (A) to (D), preferably adjacent to at least one of the layers (I). It is to have a layer (II) that

<About layer (II)>
The layer (II) is formed from a thermoplastic resin composition containing the above (C) and the following (E).
(E) At least one of polypropylene and propylene/ethylene copolymer consisting of a single composition

[Thermoplastic resin (C)]
As the thermoplastic resin (C) contained in the thermoplastic resin composition forming the layer (II), hydrogenated derivatives of C9-based petroleum resins are preferable among those described as (C) above.

The content of the thermoplastic resin (C) is preferably 3% by mass or more and 30% by mass or less, more preferably 5% by mass, when the resin composition forming the layer (II) is taken as 100% by mass. The content is from 10% by mass to 25% by mass, preferably from 10% by mass to 25% by mass. By setting the proportion of the thermoplastic resin (C) to the above lower limit or more, it is possible to impart suitable transparency and moisture resistance to the sheet. Impact resistance can be maintained.

[At least one of polypropylene and propylene/ethylene copolymer (E) consisting of a single composition]
The above (E) may be a polypropylene consisting of a single composition, that is, a propylene homopolymer, a propylene/ethylene copolymer which is a copolymer of propylene and ethylene, or a mixture thereof. It is also possible to use

When the propylene/ethylene copolymer is used, the ethylene content in the copolymer is preferably 0.5% by mass or more and 5.0% by mass or less, and more preferably 1.0% by mass or more and 4.0% by mass. The following is more preferable, and 1.5% by mass or more and 3.0% by mass or less is even more preferable. By setting the ethylene content in the copolymer within the above range, it is possible to impart suitable moisture resistance and transparency to the sheet while maintaining good film formability.

In the present invention, among these, it is preferable to use a polypropylene having a single composition because it can impart suitable moisture resistance and transparency to the sheet while maintaining good film formability.

The content of at least one (E) of the polypropylene and the propylene/ethylene copolymer consisting of the single composition is 50% by mass or more when the resin composition forming the layer (II) is taken as 100% by mass. more preferably 60% by mass or more and 99% by mass or less, and particularly preferably 70% by mass or more and 90% by mass or less. By setting the ratio of (E) above the lower limit value or more, the moisture resistance and transparency of the sheet can be maintained, and by setting the ratio to the upper limit value or less, the film-forming properties of the sheet and the thermoformability of the sheet. can be improved.

[Other additives]
In addition to the above (A) to (D), the thermoplastic resin composition forming the layer (II) may include polyolefin resins other than (A) to (D), as long as the effects of the present invention are not impaired. , resins such as polystyrene resins, polyester resins, polyolefin or polystyrene thermoplastic elastomers, heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, antibacterial and antifungal agents Additives such as agents, antistatic agents, and lubricants can be added. These may be used alone or in combination of two or more.

<Layer structure of polyolefin sheet>
The polyolefin-based sheet of the present invention has layer (I), preferably layer (II) adjacent to at least one of layer (I), and particularly preferably both sides of layer (I). It has a layer (II) adjacent to the

<Method for producing polyolefin sheet>
Next, the method for producing the polyolefin-based sheet of the present invention will be described.
The method for molding the polyolefin-based sheet of the present invention is not particularly limited. The thermoplastic resin (D) and other additives are melt-mixed with a single-screw or twin-screw extruder or the like, extruded with a T-die, quenched with a cast roll, and solidified to produce a non-stretched sheet. can.
Here, the non-stretched sheet means a sheet that is not actively stretched for the purpose of increasing the strength of the sheet. shall be taken.

When the polyolefin-based sheet of the present invention has layer (II), it may be co-extruded with layer (I) using a T-die.

〔thickness〕
The thickness of the polyolefin-based sheet of the present invention is not particularly limited, but in consideration of workability and practicality, it is preferably 100 μm or more and 1000 μm or less, more preferably 150 μm or more and 800 μm or less, and 180 μm or more. , 600 μm or less, and particularly preferably 200 μm or more and 400 μm or less. When the thickness of the propylene-based sheet of the present invention is at least the above lower limit, the sheet exhibits suitable rigidity, and is excellent in workability and curl resistance. On the other hand, if the thickness of the propylene-based sheet of the present invention is equal to or less than the upper limit, the rigidity of the sheet can be controlled within a suitable range, so that there is no problem in taking out the drug when used as PTP packaging. , can maintain excellent workability.

When the polyolefin-based sheet of the present invention has layer (I) and layer (II), the thickness of layer (I) is 40% or more and 90% or less of the thickness of the entire sheet. is preferred, more preferably 50% or more and 80% or less.

<Tensile elongation>
From the viewpoint of splittability, the polyolefin-based sheet of the present invention preferably has a tensile elongation of 300% or less when subjected to a tensile test at room temperature (23° C.) under conditions of 200 mm/min in the lateral direction. % or less, and particularly preferably 120% or less. Further, the direction of flow during sheet manufacture is referred to as the longitudinal direction of the sheet, and the direction perpendicular to the direction of flow is referred to as the lateral direction.

<Moisture resistance>
The water vapor transmission rate of the polyolefin sheet of the present invention is 0.6 g/(m ² · 24 hours) or less. Further, it is more preferably 0.5 g/(m ² ·24 hours) or less, still more preferably 0.4 g/(m ² ·24 hours) or less. By setting the water vapor transmission rate of the polyolefin-based sheet of the present invention to the above range or less, good moisture resistance can be obtained, and deterioration of the contents can be suppressed when the sheet is used for packaging of drugs and the like.

<Transparency>
When the polyolefin sheet of the present invention is used for packaging, the haze measured according to JIS K7105 is preferably 60% or less, preferably 50% or less, from the viewpoint of designability, visibility of contents, etc. is more preferable, and 45% or less is even more preferable. If the haze of the polyolefin-based sheet of the present invention is within the above range, sufficient visibility can be ensured.

<Biomass degree>
The biomass degree of the polyolefin-based sheet of the present invention is preferably 10% or more, more preferably 15% or more, and even more preferably 25% or more. If the biomass degree of the polyolefin-based sheet of the present invention is at least the above value, the environmental load can be further reduced. In addition, the said biomass degree can be calculated by the following method.
[Calculation method of biomass degree]
"Biomass content of sheet" (%) = "Biomass content of resin made from biomass resource" (%) x "Mass ratio of resin made from biomass resource in sheet"

<Molded product using polyolefin sheet>
The polyolefin-based sheet of the present invention can be formed into molded bodies of various shapes by vacuum forming, pressure forming, pressure vacuum forming, press molding, and other thermoforming. Molded bodies for packaging such as bottom materials and blister packages can be suitably produced and used.

For example, when producing a molded sheet for a bottom material for PTP packaging, the propylene-based sheet of the present invention is heated and softened with a heating plate before molding, the sheet is sandwiched between molding dies, and compressed air is injected into the molding dies. A large number of pocket portions (for example, about 9 mm in diameter and about 4 mm in depth) may be formed in the sheet surface along the concave shape of the sheet. Also, if necessary, the plug may be raised and lowered at appropriate timings during injection of compressed air to assist moldability. The bottom material for PTP packaging manufactured as described above can be combined with a lid material to form a PTP packaging material.

In addition to the above-mentioned thermoforming, aluminum foil, aluminum vapor-deposited film, plastic film (for example, biaxially oriented polypropylene film, nylon film, ethylene-vinyl alcohol copolymer film, poly It is also possible to laminate a vinylidene chloride film) or the like. It is also possible to form a composite sheet by laminating an aluminum foil or the various films described above on the front surface, back surface, or both surfaces of the sheet, and then thermoforming the composite sheet.

Further, for the purpose of enhancing the design property and secondary workability of the product, the surface of the sheet may be subjected to processing such as embossing and matting. In this case, even if a mirror-like sheet is first created and then processed with an embossing roll or matte roll, the cast roll should be changed to an embossing roll or matte roll during extrusion molding. may As long as it does not impair the gist of the present invention, the surface of the sheet may be coated with an antistatic agent, silicone, wax, etc., a surface protective sheet may be used to form a film for the purpose of preventing scratches, or a printed layer may be provided. is also possible. Any means known at present can be employed as means for forming the printed layer.

Since the polyolefin sheet of the present invention is excellent in transparency, impact resistance, moisture resistance, and curl resistance, it is used as a PTP for packaging solid agents such as capsules and tablets, granular foods, etc. in the packaging field of pharmaceuticals, foods, etc. It can be used for packaging and blister packages for packaging foods in the food packaging field.

Examples are shown below, but the present invention is not limited by these. Various measurements and evaluations of the raw material and the polyolefin-based sheet were performed as follows, and the biomass content was calculated according to the method described above. In addition, the direction of flow of the polyolefin-based sheet from the extruder is called the vertical direction, and the direction perpendicular thereto is called the horizontal direction.

<Raw material evaluation>
(1) Measurement of storage elastic modulus (E′) Each resin was heated at a set temperature of 180 to 220° C., compressed with a heat press under a load of 20 MPa for 30 seconds, cooled and formed into a sheet. The dynamic viscoelasticity of the obtained film was measured using a viscoelasticity spectrometer DVA-200 (manufactured by IT Keisoku Co., Ltd.) under the following conditions. From the measurement results, the value of the storage elastic modulus (E') at 24°C was defined as the rigidity of each resin. [Measurement condition]
Vibration wave number: 10Hz
Strain: 0.1%
Heating rate: 3°C/min Measurement temperature: -50°C to 200°C

<Evaluation of Polyolefin Sheet>
(1) Elongation (tensile elongation)
A strip of 1 cm wide x 9 cm long test piece was cut from a polyolefin sheet, and a precision universal testing machine AG-X plus (manufactured by Shimadzu Corporation) was used to measure the breakage of the test piece under the following conditions. Tensile elongation was determined from the elongation between wires and evaluated according to the following criteria.
[Measurement condition]
Temperature: Room temperature (23°C)
Measurement direction: the horizontal direction of the sheet (the length direction of the test piece is the horizontal direction of the sheet)
Tensile speed: 200 mm/min Gauge line distance: 25 mm

[Evaluation criteria]
◎: Tensile elongation is 120% or less ○: Tensile elongation is over 120% and 300% or less △: Tensile elongation is over 300% and 450% or less ×: Tensile elongation is over 450%

(2) Moisture resistance (water vapor transmission rate)
Based on JIS K7129B, using PERMATRAN W 3/31 (manufactured by MOCON), the water vapor transmission rate of the polyolefin-based sheet was measured in an atmosphere of 40° C. and 90% RH, and evaluated according to the following criteria.
[Evaluation criteria]
◎: Water vapor transmission rate is 0.4 g/(m ² · 24 hours) or less ○: Water vapor transmission rate is over 0.4 g/(m ² · 24 hours) and 0.6 g/(m ² · 24 hours) or less ×: Water vapor transmission rate exceeds 0.6 g / (m ² · 24 hours)

(3) Transparency (Haze)
Based on JIS K7105, the total light transmittance and diffuse transmittance of the polyolefin-based sheet were measured using a haze meter. The haze was calculated from the total light transmittance and diffuse transmittance obtained by the following formula and evaluated according to the following criteria.
[Haze] (%) = [diffuse transmittance] / [total light transmittance] x 100
[Evaluation criteria]
◎: Haze is 45% or less ○: Haze is over 45% and 60% or less ×: Haze is over 60%

<Evaluation of PTP sheet>
(4) Dividability A polyolefin sheet is molded into a PTP packaging bottom sheet using a PTP molding device (CKD Co., Ltd., FBP-300E). It was heat sealed with Furthermore, after making a slit from the bottom material sheet side to a depth of 200 μm, it was punched to a size of about 40 mm × about 95 mm and a corner R = 5 mm (the direction of 40 mm is the longitudinal direction of the sheet), as shown in FIG. Various PTP moldings were obtained.
After bending the slit portion of the molded product five times by hand, the product was torn from the end to evaluate the splittability. A sample that was torn at one time without delay was evaluated as having good splittability, and a sample that was caught or the tear surface was elongated was rated as poor splittability, and was rated as “x”.

Prior to the examples, the following raw materials were prepared.

[Polyethylene resin (A)]
(A-1): Bio-polyethylene resin (density = 0.953 g/cm ³ , MFR = 2.0 g/10 min, biomass degree = 96%)
(A-2): Bio-polyethylene resin (density = 0.948 g/cm3, MFR = 1.0 g/10 min, biomass degree = 94%)

[Crystal Nucleating Agent (B)]
(B-1): fatty acid metal salt

[Thermoplastic resin (C)]
(C-1): Hydrogenated derivative of C9 petroleum resin (softening point = 125°C)

[Thermoplastic resin (D)]
(D-1): Random polypropylene (propylene/ethylene = 98/2 mass% copolymer, E' = 1600 MPa)
(D-2): cyclic polyolefin (E' = 2100 MPa)
(D-3): cyclic polyolefin (E' = 1900 MPa)
(D-4): homopolypropylene (propylene homopolymer, E′=1700 MPa)
(D'-1): random polypropylene (propylene/ethylene = 97/3 mass% copolymer, E' = 940 MPa)

[Polypropylene resin (E)]
(E-1): homopolypropylene (propylene homopolymer, E′=1480 MPa)

<Example 1>
After dry blending (A-1), (B-1), (C-1) and (D-1) as layer (I) at a mixing mass ratio of 60:2.5:20:20, The mixture was kneaded at 230° C. using a 40 mmφ single-screw extruder. As layer (II), (C-1) and (E-1) were dry-blended at a mixing mass ratio of 20:80, and kneaded at 230° C. using a 32 mmφ single-screw extruder. Layer (I) and layer (II) were extruded from a T-die so that the lamination ratio was II:I:II=1:4:1, and then quenched with a casting roll at about 45° C. to form a sheet with a thickness of 300 μm. was made. The resulting sheet was evaluated for elongation, moisture resistance, transparency and splittability. The results are shown in Table 1 below.

<Examples 2 to 6, Comparative Examples 1 and 2>
A sheet having a thickness of 300 μm was prepared and evaluated in the same manner as in Example 1, except that layers (A) to (D) were mixed in a predetermined ratio shown in Table 1 below as layer (I). Table 1 shows the results.

<Reference example>
As a reference example, a sheet having a thickness of 300 μm and consisting of a single layer of homopolypropylene conventionally used as a bottom material for PTP packaging was prepared. The above sheet was similarly evaluated for elongation, moisture resistance, transparency and splittability. The results are shown in Table 1 below.

From the results of Table 1 above, Example 1 having a layer (I) containing components (A) to (D) and formed from a thermoplastic resin having a predetermined content of components (C) and (D) The polyolefin sheets of Nos. 1 to 6 were excellent in splittability, moisture resistance and transparency.

On the other hand, the polyolefin sheet of Comparative Example 1 containing no component (D) and the polyolefin sheet of Comparative Example 2 containing a thermoplastic resin having a low storage elastic modulus as the component (D) were inferior in splittability.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, the invention is not limited to the embodiments disclosed herein. It should be understood that it can be changed as appropriate within the range not contrary to the gist or idea of the invention that can be read from the scope of claims and the entire specification, and films that involve such changes are also included in the technical scope of the present invention. must.

The polyolefin-based sheet of the present invention is excellent in splittability, moisture resistance and transparency, and therefore can be suitably used for various types of packaging, particularly as a bottom material for PTP packaging.

Claims (7)

It has a layer (I) formed from a thermoplastic resin composition containing the following (A), (C) and (D), and the thermoplastic resin composition forming the layer (I) is 100% by mass. when
A polyolefin-based sheet in which (C) is 3% by mass or more and 30% by mass or less, and (D) is 3% by mass or more and 60% by mass or less.
(A) A polyethylene resin having a density of 0.935 g/cm ³ or more as measured according to JIS K7112 (C) A softening point of 80 to 170° C., and a petroleum resin, a terpene resin, a coumarone-indene resin, and a rosin at least one thermoplastic resin (D) having a storage modulus (E′) at 24° C. of 1000 MPa or more, and propylene incompatible with (A) system resin 2. The polyolefin sheet according to claim 1 , wherein the propylene resin is homopropylene or a copolymer of propylene and α-olefin . Having a layer (II) adjacent to at least one of the layers (I), the layer (II) is formed from a thermoplastic resin composition containing the (C) and the following (E), and the layer (II) is 3. The polyolefin sheet according to claim 1, wherein said (C) is 3% by mass or more and 30% by mass or less when the thermoplastic resin composition to be formed is taken as 100% by mass.
(E) At least one of polypropylene and propylene/ethylene copolymer consisting of a single composition The polyolefin according to any one of claims 1 to 3, which has a water vapor transmission rate of 0.6 g/(m ² ·24 hours) or less measured at a temperature of 40°C and a relative humidity of 90% based on the JIS K7129B method. system sheet. The polyolefin sheet according to any one of claims 1 to 4, wherein (A) is a biopolyethylene resin. A bottom material for press-through package packaging using the polyolefin-based sheet according to any one of claims 1 to 5. A press-through package packaging material comprising the bottom material for press-through package packaging according to claim 6 and a lid material.

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