JP6500772B2 - Heat seal sheet, method for producing the same, and press-through package - Google Patents

Description

  The present invention relates to a heat seal sheet, a method of manufacturing the same, and a press-through package.

Press-through packaging (hereinafter sometimes abbreviated as "PTP") is used for packaging capsules, tablets and medicines, foods and the like.
Conventionally, as PTP, a container made of a resin sheet and provided with a plurality of pocket parts for containing contained articles and a lid material provided with a heat adhesive layer on one side of aluminum foil are widely used. There is. The lid is attached to the container by heat sealing to seal the opening of the pocket. The substance contained in the pocket of the PTP is taken out by pushing the bulge of the pocket with fingers and breaking the lid at a position corresponding to the pocket.

In such a PTP, aluminum foil fragments may be generated when the contained material is taken out, and when taking the contained material, there is an accident that the aluminum foil fragments are accidentally swallowed together with the contained material. It has been reported. Therefore, in order to reduce the load on the human body when the lid material is accidentally swallowed, it has been proposed to use paper as the base material of the lid material.
On the other hand, for weak people such as old people and infants, there is a case where it is difficult to take out the contained object from the PTP due to lack of muscular strength pushing the pocket part of the PTP. In hospitals and dispensing pharmacies, etc., it takes time and effort to take out one drug at a time from PTP due to handling several tens to several hundreds of drugs a day, and it is a request that you want to easily take out many drugs at once. There is. Therefore, it is proposed that PTP have an easy peel function.

Paper tends to have high burst strength due to the entanglement of pulp fibers. Therefore, when paper is used instead of aluminum foil as a base material of a lid material, the ease of taking out (press-through aptitude) at the time of pushing out a pocket part and taking out an accommodation thing is inferior.
To solve these problems, PTP lids that use oxidized pulp or oxidized cellulose as the raw material for the paper base of the lid material and have a number of folds of 5 or less measured according to the folding strength test method using the MIT tester A material has been proposed (Patent Document 1).
However, the PTP lid does not have sufficient paper strength to withstand easy peel, so the easy peel suitability is low. For example, when the PTP lid is to be peeled off from the container by an easy peel method, the lid tends to break.

As a PTP having both press-through and easy-peel functions, a laminate of a paper base and an aluminum foil layer is used as the base of the lid, and only the paper base of the lid is cut at the position corresponding to the pocket And the peel strength between the container and the thermal adhesive layer of the lid member is specified within a specific range (Patent Document 2).
However, since the lid includes the aluminum foil layer, the effect of reducing the load on the human body when the lid is accidentally consumed is insufficient. In addition, since the paper base is provided with a cut in advance, there is a possibility that the next pocket may be opened when pushing the pocket to take out the contained object one by one.

JP 2001-301810 A JP 2003-63558 A

  An object of the present invention is to provide a heat seal sheet which is made of paper and has excellent easy peelability, a method for producing the same, and PTP using the same for a lid material.

In order to solve the above-mentioned subject, the present invention adopted the following composition.
[1] A paper substrate and a heat adhesive layer laminated on one side of the paper substrate,
The paper base includes a base paper made of pulp, and a coating layer containing a polyacrylamide resin provided on at least the surface on the heat adhesive layer side of the base paper.
The freeness of the pulp measured according to JIS P 8121-2: 2012 is 600 mL or less,
The content of the polyacrylamide resin in the coating layer provided on the surface of the heat adhesive layer side is 0.1 to 10.0 g / m ² ,
The heat seal sheet, wherein the basis weight of the paper substrate is 18 g / m ² or more.
[2] The heat seal sheet according to [1], wherein the following irregularity freeness of the pulp is 50 to 500 mL.
Anomalous freeness: Measured according to JIS P 8121-2: 2012 except that the solid content concentration of the pulp suspension was changed from 0.30% ± 0.01% to 0.030% ± 0.001% Freeness.
[3] The heat seal sheet according to [1] or [2], wherein the basis weight of the paper base is 50 g / m ² or less.
[4] The heat seal sheet according to any one of [1] to [3], which is a lid for PTP.
[5] A method for producing a heat seal sheet comprising a paper substrate and a heat adhesive layer laminated on one side of the paper substrate,
Applying a coating solution containing a polyacrylamide resin to at least one surface of a base paper made of pulp, and drying to form a coating layer to obtain a paper substrate;
Laminating a thermal adhesive layer on the surface of the paper substrate on which the coating layer is provided;
Have
The freeness of the pulp measured according to JIS P 8121-2: 2012 is 600 mL or less,
The application amount of the coating liquid applied to the side of the base paper on which the heat adhesive layer is laminated is 0.1 to 10.0 g / m ² in terms of the amount of the polyacrylamide resin,
The basis weight of the said paper base material is 18 g / m < ² > or more, The manufacturing method of the heat seal sheet characterized by the above-mentioned.
[6] A container comprising a container and a lid member, wherein the container is provided with a plurality of pocket portions for containing objects, and a flange portion provided around the openings of the plurality of pocket portions and bonded to the lid member. A PTP comprising
The PTP, wherein the lid material is the heat seal sheet according to any one of [1] to [4].
[7] When the lid material can be peeled off from the container by the easy peel method, and the lid member is peeled off by the easy peel method, the heat adhesive layer is the paper base at the portion in contact with the flange portion. The PTP according to [6], wherein the lid member and the flange portion are pasted together so as to be separated from the material and remain on the flange portion side.

  According to the present invention, it is possible to provide a heat seal sheet whose base material is made of paper and has excellent easy peelability, a method for producing the same, and PTP using the same for a lid material.

It is a sectional view showing typically the first embodiment of the heat seal sheet of the present invention. It is a sectional view showing typically the first embodiment of PTP of the present invention. It is sectional drawing which shows typically an example of the state which peeled the cover material from the container by easy peel system in PTP shown in FIG. It is sectional drawing which shows typically the other example of the state which peeled the cover material from the container by easy peel system in PTP shown in FIG.

<Heat seal sheet>
The heat seal sheet of the present invention comprises a paper base and a heat adhesive layer laminated on one side of the paper base,
The paper base includes a base paper made of pulp, and a coating layer containing a polyacrylamide resin provided on at least the surface on the heat adhesive layer side of the base paper.
The content of the polyacrylamide resin in the coating layer provided on the heat adhesive layer side is 0.1 to 10 g / m ² ,
The basis weight of the paper base material is 18 g / m ² or more.

Hereinafter, a heat seal sheet of the present invention will be described by showing an embodiment with reference to the attached drawings.
FIG. 1 is a cross-sectional view schematically showing a first embodiment of the heat seal sheet of the present invention.
The heat seal sheet 1 of the present embodiment includes a paper base 3 and a heat adhesive layer 5 laminated on one side of the paper base 3.

(Paper base)
The paper substrate 3 includes a base paper made of pulp, and a coating layer provided on at least the surface of the base paper on the heat adhesive layer 5 side. The coating layer contains a polyacrylamide resin.
In the paper substrate 3, the coated layer is usually at least partially below the surface of the base paper. A part of the coating layer may be present on the surface of the base paper.
Therefore, the base paper constituting the inside of the paper base 3 usually contains a polyacrylamide resin derived from the coating layer. The concentration of the polyacrylamide resin in the base paper (the density in the thickness direction of the base paper) may be uniform or may have a concentration gradient such that the density decreases inward from the surface of the base paper.

  Wood pulp, non-wood pulp, etc. are mentioned as a pulp which comprises base paper. As wood pulp, softwood pulp, hardwood pulp and the like may be mentioned, and any may be used. There is no particular limitation on the cooking method or the bleaching method. Examples of non-wood pulp include hemp pulp, kenaf pulp and bamboo pulp. One of these pulps may be used alone, or two or more thereof may be used in combination.

The freeness of the pulp constituting the base paper is 600 mL or less, preferably 350 mL or less, as freeness (hereinafter also referred to as "standard freeness") measured according to JIS P 8121-2: 2012.
In general, with regard to the relationship between pulp beating and paper strength, it is difficult to obtain paper strength in a state where it is not recommended to be enough refined, because the binding between pulp fibers is weak and the point of interfiber bonding (hydrogen bonding) is also small. It is thought that the paper strength is improved by advancing the beating to some extent. If the standard freeness of the pulp is equal to or less than the above upper limit value, the paper strength of the paper base 3 is sufficiently high, and the easy peel aptitude of the heat seal sheet 1 is excellent.

The degree of beating of the pulp is more preferably 50 to 500 mL, still more preferably 100 to 500 mL, as the following irregular freeness.
Anomalous freeness: Measured according to JIS P 8121-2: 2012 except that the solid content concentration of the pulp suspension was changed from 0.30% ± 0.01% to 0.030% ± 0.001% Freeness.
Anomalous freeness is suitable for evaluation in a state where the beating has progressed to a certain extent, compared to standard freeness, because the amount of pulp used for measurement is one-tenth of standard freeness. For example, 770 mL of anomalous freeness is about 380 mL of standard freeness.

If the irregular freeness of the pulp is within the above range, it is possible to achieve both excellent easy peel aptitude and press-through aptitude.
As described above, the paper strength is improved by advancing the beating of the pulp to a certain extent. However, if the beating is advanced excessively, the damage to the fibers themselves proceeds, resulting in a decrease in paper strength.
If the anomalous freeness is below the upper limit value of the above range, the paper strength decreases and the burst strength of the paper base 3 decreases, and excellent press-through suitability can be obtained. However, it is considered that the material breakage at the time of peeling in the easy peel method is relatively difficult to occur because the binding between fibers is also advanced.
If the anomalous freeness is equal to or more than the lower limit value of the above range, excessive decrease in paper strength hardly occurs, and the easy peel aptitude is excellent. In addition, the time required for refining the pulp is not long when producing the base paper, the dewaterability at paper making is also good, and the operation efficiency is excellent.

The base paper may contain fiber materials other than pulp, such as rayon fibers, nylon fibers, and other heat fusion fibers as secondary materials.
The base paper may contain various internal chemicals for papermaking, retention aids, antifoaming agents, fillers, coloring agents and the like. Internal additives include various fixing agents such as sizing agents, paper strength agents, wet paper strength agents, sulfate bands, cationized starch and the like.

The base paper can be produced by making a papermaking material containing pulp slurry.
The pulp slurry is obtained by beating the pulp in the presence of water. Internally added chemicals for papermaking and the like are added to the pulp slurry obtained by beating to prepare a papermaking material.
The pulp beating method and the beating apparatus are not particularly limited, but a double disc refiner (DDR) having high beating efficiency is preferably used.
The papermaking of the papermaking material can be carried out by a conventional method.
The basis weight of the base paper is set in accordance with the basis weight of the paper substrate 3 and the application amount of the primer.
In addition, the freeness (standard freeness, anomalous freeness) of the pulp used for producing the base paper is equal to the freeness of the pulp constituting the base paper.

The coating layer contains a polyacrylamide resin.
Polyacrylamide resins are polymers having (meth) acrylamide units. "(Meth) acrylamide" is a generic term for acrylamide and methacrylamide. The polyacrylamide resin may have one or both of an acrylamide unit and a methacrylamide unit. The polyacrylamide resin may have other units other than (meth) acrylamide units.

As polyacrylamide resin, anionic polyacrylamide resin, cationic polyacrylamide resin, amphoteric polyacrylamide resin, nonionic polyacrylamide resin etc. are mentioned. As these, known materials can be used as paper strengthening agents etc. in the papermaking field, and those described in, for example, JP-A-2002-317393, JP-A-2004-231901, JP-A-2014-205938 and the like can be mentioned. Be
The polyacrylamide resin may be used alone or in combination of two or more. From the viewpoint of easy availability, anionic polyacrylamide resins are preferred.
The anionic polyacrylamide resin contains an anionic functional group such as a carboxy group, a sulfonic acid group, a phosphoric acid group, or a salt thereof, and, for example, (meth) acrylamide and an anionic functional group-containing monomer (acrylic acid etc.) The copolymer, the partial hydrolyzate of poly (meth) acrylamide, etc. are mentioned.

As a polyacrylamide resin, one having a mass average molecular weight (Mw) of 50,000 to 500,000 is preferable, and one having 50,000 to 300,000 is more preferable.
If the mass average molecular weight of the polyacrylamide resin is within the above range, the effect of suppressing the fuzzing of the surface of the paper substrate is more excellent without increasing the burst strength measured according to ISO 2758 of the base paper. If the mass average molecular weight is at least the lower limit value of the above range, the effect of suppressing the fuzzing of the surface of the paper substrate 3 when the thermal adhesive layer 5 peels off is easily obtained. If the mass average molecular weight is not more than the upper limit value of the above range, the viscosity of the coating solution for forming the coating layer (primer described later) is sufficiently low to be coated, and preparation and coating of the primer are easy. . In addition, the concentration of the polyacrylamide resin in the primer can be increased, and the target coating amount can be easily obtained. When the weight average molecular weight exceeds 500,000, it is used as an internally added paper strengthening agent, but the viscosity of the solution becomes high, the preparation and coating of the primer are difficult, and it is difficult to obtain a satisfactory coated amount.
The mass average molecular weight of the polyacrylamide resin is a polyethylene oxide equivalent value measured by gel permeation chromatography (GPC).

The coating layer may contain other components other than the polyacrylamide resin, as needed, as long as the effects of the present invention are not impaired.
Other components include, but are not limited to, for example, starch, modified starch, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, diisobutylene / maleic anhydride co-weight Water-soluble polymer compounds such as combined salts, styrene / maleic anhydride copolymer salt, styrene / butadiene copolymer emulsion, acrylic ester copolymer emulsion, urethane resin, urea resin, styrene-acrylic resin emulsion, ethylene- Examples thereof include aqueous polymer compounds such as acrylic resin emulsions, mold release agents, antifoaming agents, dispersants, wetting agents, colored dyes, colored pigments, white pigments and the like. One of these may be used alone, or two or more may be used in combination.

  50-100 mass% is preferable with respect to the total mass (100 mass%) of a coating layer, as for content of the polyacrylamide resin in a coating layer, 80-100 mass% is more preferable. When the content of the polyacrylamide resin is equal to or more than the lower limit value of the above range, the easy peel suitability is good.

In the paper base material 3, the content of the polyacrylamide resin in the coating layer provided on the surface on the heat adhesive layer 5 side is 0.1 to 10.0 g / m ² , 0.1 to 5.0 g / m ^{2 2} is more preferable, and 0.2 to 3.0 g / m ² is more preferable. In particular, when the basis weight of the heat bonding layer 5 is 2.0 g / m ² or more, it is preferable to set the lower limit of the above-mentioned preferable range to 0.5 g / m ² .
If the content of the polyacrylamide resin per unit area of the coating layer is equal to or more than the lower limit value of the above range, the paper substrate 3 and the heat bonding layer 5 peel well at the time of easy peeling, and the surface of the paper substrate 3 It is hard to cause fuzz and substrate destruction. When the content is equal to or less than the upper limit value of the above range, the burst strength of the heat seal sheet 1 can be suppressed to be low, and the press-through suitability is excellent.

In the case where a coating layer is provided on the surface of the paper base 3 opposite to the thermal adhesive layer 5 side, the content of the polyacrylamide resin in the coating layer is not particularly limited, but preferably 10.0 g / m ² or less. And 0.1 to 5.0 g / m ² are more preferable, and 0.2 to 3.0 g / m ² are more preferable. If the application amount is equal to or less than the upper limit value of the above range, the burst strength of the heat seal sheet 1 can be suppressed low, and the press-through suitability is excellent.

The basis weight of the paper substrate 3 is 18 g / ^{m 2} or more, 20 g / ^{m 2} or more. If the basis weight of the paper base material 3 is equal to or more than the lower limit value, the strength which can withstand easy peel is easily obtained, and the base material destruction at the time of peeling hardly occurs.
Although the basis weight of the upper limit of the paper substrate 3 is not particularly limited, when using a heat-seal sheet 1 as a lid material for a PTP is preferably at 50 g / ^{m 2} or less, more preferably 40 g / ^{m 2,} 35 g / ^{m 2} or less is more preferred. If the basis weight of the paper substrate 3 is equal to or less than the upper limit, the burst strength of the heat seal sheet 1 can be suppressed to a low level, and the force required to push out the contained object from the PTP pocket is small. Excellent in suitability.
The basis weight of the paper base 3 is measured in accordance with JIS P 8124: 2011. The basis weight of the base paper is also the same.

The density of the paper substrate ³ is preferably 0.95 to 1.30 g / cm ³ , more preferably 1.00 to 1.30 g / cm ³ , still more preferably 1.00 to 1.25 g / cm ³ , and 1 .10 to 1.25 g / cm ³ is particularly preferred. If the density of the paper substrate 3 is equal to or more than the lower limit value, the press-through suitability is more excellent. If the density of the paper substrate 3 is equal to or less than the upper limit value, the easy peel aptitude is more excellent.
The density of the paper substrate 3 can be obtained by calculation from the measured values of thickness and basis weight by measuring the thickness according to JIS P 8118: 1998.

The paper substrate 3 can be manufactured by applying a coating solution containing a polyacrylamide resin (hereinafter, also referred to as "primer") on at least one surface of a base paper and drying to form a coated layer.
When the primer is applied to one side of the base paper, the primer is applied on the side on which the heat adhesive layer 5 is laminated.

The primer usually comprises a liquid medium. As the liquid medium, one capable of dissolving a polyacrylamide resin is preferable, and for example, water can be mentioned.
The primer may optionally contain the other components described above.

  50-100 mass% is preferable with respect to the total solid (100 mass%) in undercoat, and, as for content (concentration) of polyacrylamide resin in undercoat, 80-100 mass% is more preferable. The total solids content is the total of the primer minus the liquid medium and is the sum of the polyacrylamide resin and the other ingredients. The content of polyacrylamide resin relative to the total solids is equal to the content of polyacrylamide resin relative to the total mass of the coating layer.

The application amount of the primer to the base paper is set according to the amount of polyacrylamide resin.
The application amount of the primer on the side of the base paper on which the heat adhesive layer 5 is laminated is 0.1 to 10 g / m ² in terms of the amount of polyacrylamide resin, 0.1 to 5.0 g / m ^2. m ² is more preferable, and 0.2 to 3.0 g / m ² is more preferable. In particular, when the basis weight of the heat bonding layer 5 is 2.0 g / m ² or more, it is preferable to set the lower limit of the above-mentioned preferable range to 0.5 g / m ² . The application amount of the primer converted to the amount of polyacrylamide resin is equal to the content of polyacrylamide resin in the coating layer.

When the primer is applied to the side of the base paper opposite to the side on which the heat adhesive layer 5 is laminated, the amount of application is not particularly limited, but 10.0 g / m in terms of the amount of polyacrylamide resin. ² or less are preferable, 0.1-5.0 g / m < ² > is more preferable, 0.2-3.0 g / m < ² > is further more preferable.

The method for applying the primer is not particularly limited, and various known wet application methods can be used. For example, it can be carried out using an on-machine size press apparatus of a paper machine, a transfer roll coater (a shim sizer, a gate roll coater, etc.), a spray apparatus or the like. In the off-machine, a general coating apparatus such as a blade coater, an air knife coater, a roll coater, a reverse roll coater, a shim sizer, a gate roll coater, a bar coater, a curtain coater, a slot die coater, a gravure coater, a chamber coater The coating can be performed using a brush coater, a two-roll coater, a bill blade coater, a short dwell coater, or the like.
In consideration of operability and productivity, the application and drying of the primer are preferably performed on an on-machine basis. Therefore, the type of paper machine used to make the base paper is not particularly limited, such as a fourdrinier paper machine, a fourdrinier paper machine, a cylinder paper machine, etc., but one equipped with an on-machine coating machine It is preferable to use

The applied primer is usually at least partially penetrated into the base paper, and the base paper after application contains a polyacrylamide resin. When a part of the primer penetrates into the base paper, a layer containing a polyacrylamide resin on the coated side of the base paper by drying the primer that has not penetrated on the coated surface (hereinafter, “subbing layer” Also known as
The paper substrate 3 may or may not have a subbing layer on the coated surface of the base paper. Even in the absence of the subbing layer, excellent easy peelability can be obtained because the polyacrylamide resin is impregnated on the surface of the base paper and in the vicinity thereof. The presence or absence of the undercoat layer can be confirmed by thermal decomposition GCMS (gas chromatography mass spectrometry) or the like by shaving the surface and the middle layer portion with a razor or the like.
The concentration of the polyacrylamide resin in the base paper (the density in the thickness direction of the base paper) may be uniform or may have a concentration gradient such that the density decreases inward from the surface of the base paper.

  Examples of the method of forming the undercoat layer include a method of using a transfer roll coater such as a gate roll coater, a method of increasing the content of the polyacrylamide resin in the undercoat agent, and the like. In the case of using a transfer roll coater, the undercoating layer is less likely to penetrate into the base paper than in the case of using a size pressing apparatus, so the undercoating layer tends to be formed and the concentration gradient of the polyacrylamide resin as described above tends to be formed. . In addition, as the content of the polyacrylamide resin in the primer is higher, the viscosity of the primer is higher, the primer penetrates into the base paper, and the undercoat layer is easily formed, as described above. A resin concentration gradient tends to be formed.

(Heat bonding layer)
The material constituting the thermal adhesive layer 5 is not particularly limited, and materials exhibiting various thermal adhesiveness can be used, and the adherend to which the thermal adhesive layer 5 is thermally bonded (for example, the heat seal sheet is a PTP lid) In some cases, it is selected appropriately according to the material of the PTP container) and the heat bonding conditions.
As a material which expresses heat adhesiveness, an ethylene-vinyl acetate copolymer, an ethylene- (meth) acrylic acid copolymer, an acrylic ester polymer, polyethylene, a polyethylene-polybutene mixture etc. are mentioned, for example. One of these may be used alone, or two or more may be used in combination.

The heat adhesive layer 5 can be formed, for example, by applying a heat seal agent containing the above-described material and a liquid medium to one surface of the paper substrate 3 and drying it.
The heat sealing agent may be an aqueous heat sealing agent in which the above-described material is dissolved or dispersed in water, or may be a solvent-based heat sealing agent in which the above-described material is dissolved in a solvent.
Examples of the water-based heat sealing agent include ethylene-vinyl acetate copolymer emulsion, ethylene- (meth) acrylic acid copolymer emulsion, acrylic acid ester polymer emulsion, polyethylene emulsion, polyethylene-polybutene mixed emulsion, etc. . Among these, ethylene-vinyl acetate copolymer emulsion, acrylic ester emulsion and polyethylene emulsion express stable peeling force and do not increase the burst strength measured according to ISO 2758 on the paper substrate surface. It is preferable because it has a high effect of suppressing the buildup.

It does not specifically limit as a coating method of a heat sealing agent, It can carry out using various well-known wet coating methods. For example, the method similar to the application method of a primer is mentioned.
With regard to the drying equipment, in the case of a direct contact method with a coated surface using a cylinder drier, since there is a risk that the dryer or canvas may be contaminated, drying with a drying equipment such as an air dryer or an infrared heater which does not contact the coated surface is preferable.

The basis weight (the dry coating amount of the heat sealing agent) of the heat bonding layer 5 is not particularly limited, and is appropriately selected according to the material of the adherend to which the heat bonding layer 5 is bonded and the heat sealing conditions. Preferably it is 0.1-30 g / m < ² >, More preferably, it is 0.5-20 g / m < ² >, More preferably, it is 2.0-20 g / m < ² >. If the basis weight of the thermal bonding layer 5 is at least the lower limit value of the above range, it is easy to obtain a satisfactory thermal adhesive strength. For example, in the case where the lid is thermally bonded to a container as a PTP lid, the lid is less likely to peel off when the pocket portion is pushed to push out the contained object. If the basis weight of the heat bonding layer 5 is equal to or less than the upper limit value of the above range, breakage of the paper substrate 3 is less likely to occur at the time of easy peeling. In addition, the thermal adhesive layer 5 is unlikely to exhibit spinnability, and contamination of the contained material is less likely to occur.

(Burst strength)
The burst strength of the heat seal sheet 1 measured according to ISO 2758 is preferably 40 to 200 kPa, more preferably 50 to 150 kPa, and still more preferably 60 to 130 kPa.
When the heat seal sheet 1 is used as a lid for PTP with a burst strength of 200 kPa or less, the force required to push in the pocket portion to push out the lid to take out the contained object does not increase. The burden is small even for the powerless person. In addition, it is easy to adjust the degree of application of force, and when the force is applied, it is possible to push and break the lid without popping out the contained material. In addition, adhesion of the lid to the taken-out object, and accidental ingestion of the lid due to taking such an object are unlikely to occur. In addition, since the force required to push and break the lid is small, deformation and cracking of the contained object are less likely to occur when the lid is pushed. In particular, in the case of a capsule containing a granular drug, the deformation of the capsule may interfere with the extrusion.
When the burst strength is 40 kPa or more, it has sufficient strength to withstand easy peel, and breakage of the paper substrate 3 is unlikely to occur at the time of peeling. Further, when the heat seal sheet 1 is used as a lid for PTP, the contained object is hardly pushed out by a small impact, and the handling of the PTP becomes easy.
The burst strength of the heat seal sheet 1 is determined by the freeness of the pulp constituting the paper base 3 (standard freeness, irregular freeness), the basis weight of the paper base 3, the content of polyacrylamide resin in the coating layer (coating amount of primer ) Can be adjusted.

(Production method)
The heat seal sheet 1 can be manufactured, for example, by a manufacturing method having the following steps (α2) to (α3). The production method may optionally include the following step (α1) before the step (α2).
(Α1) A process of refining pulp in the presence of water to obtain a pulp slurry, adding an internal chemical for paper making to the pulp slurry to prepare a papermaking material, and papermaking the papermaking material to obtain a base paper .
(Α2) A step of applying a primer to at least one surface of a base paper made of pulp and drying to form a coated layer to obtain a paper substrate 3.
(Α3) The heat adhesive layer 5 is laminated on the surface of the paper substrate 3 on which the coating layer is provided (surface having a content of polyacrylamide resin of 0.1 to 10 g / m ² ), and the heat seal sheet 1 is obtained. Step of obtaining.
Steps (α1) to (α3) can be carried out according to the above-mentioned procedures.

(Action effect)
The heat seal 1 has an application layer containing a polyacrylamide resin at a specific content on the surface on the heat adhesive layer 5 side and is easy to use since it is a paper substrate 3 having a specific basis weight. Excellent in peel aptitude. For example, when the heat seal 1 is thermally bonded to an adherend (container of PTP, etc.) and then peeled from the adherend, the thermal adhesive layer 5 remains attached to the adherend side from the interface with the paper substrate 3 It is easy to peel off and the paper substrate 3 is hard to tear. In addition, when the heat bonding layer 5 peels off, it is hard to cause fuzzing of the surface of the paper substrate 3 and peeling of the paper piece from the surface. Since the paper base 3 is hard to tear, when the heat seal 1 is peeled from the adherend by the easy peel method, the whole can be peeled at one time. Further, since fluffing and peeling of the paper sheet are suppressed, it is possible to prevent the fibers dropped from the fluffed portion and the peeled paper piece from adhering to the adherend or the contained object. Moreover, when taking a to-be-stored thing, it can prevent drinking accidentally the fiber and the paper piece which adhered.
Further, in the heat seal 1, since the base material is mainly made of paper, load on the human body when accidental ingestion of the heat seal fragments is smaller than that in the case of using aluminum foil as the base material.
Furthermore, depending on the irregular freeness of the pulp constituting the paper base 3 and the basis weight of the paper base 3, the press-through ability can be made excellent.

An application layer containing a polyacrylamide resin is provided on the surface of the paper substrate 3 on which the heat adhesive layer 5 is laminated, so that the heat adhesive layer 5 peels off from the paper substrate 3 The reason why it is possible to suppress breakage, fuzzing of the surface, falling of a sheet from the surface, etc. is considered as follows.
Polyacrylamide resin is a hydrogen which an amide group in the molecule forms a hydrogen bond with a hydroxyl group in cellulose and hemicellulose molecules or with an amide group of polyacrylamide resin itself and acts between pulp fibers Increase the number of bonds. Thereby, the bonding of the network of pulp fibers is strengthened, and when the heat seal sheet is peeled from the adherend, it is possible to prevent the pulp fibers from being taken by the heat adhesive layer peeled off from the paper substrate 3.
Water-soluble polymers such as polyacrylamide resin, polyvinyl alcohol and hydrophobized starch are known as paper-strengthening agents in the papermaking field, but according to the study of the present inventors, polyacrylamide resin is It is excellent in the effect which controls the above-mentioned base material destruction and fuzzing compared with water-soluble polymer.
Moreover, the viscosity of the aqueous solution is lower than other water-soluble polymers, and the polyacrylamide resin is excellent in stability (the aqueous solution is less likely to be gelled). Therefore, the concentration of the polyacrylamide resin can be increased while securing sufficient coatability. When the concentration of the polyacrylamide resin in the primer is high, the coating amount per one side can be easily made 0.1 g / cm ² or more.
Polyacrylamide resins also make it difficult to increase the burst strength (measured according to ISO 2758) of the base paper. Therefore, the easy peel aptitude can be enhanced without impairing the press through aptitude of the base paper.

The heat seal 1 is useful as a lid material for PTP when both the easy peelability and the press-through ability are excellent.
However, the application of the heat seal 1 is not limited to the lid for PTP, and for applications other than PTP, for example, a package obtained by processing a heat seal sheet into a bag, a lid for blister pack, and a liquid container for drinking by drinking a straw. It is applicable also to uses, such as a cover material.

As mentioned above, although an embodiment was shown and explained about a heat seal sheet of the present invention, the present invention is not limited to the above-mentioned embodiment. The configurations and combinations thereof in the above embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention.
For example, another layer may be provided between the paper base 3 of the heat seal sheet 1 and the heat adhesive layer 5. Examples of the other layers include a water vapor barrier layer, an oxygen barrier layer, a print layer, a printability improving layer, an overprint layer, a light shielding layer and the like. The other layer provided between the paper substrate 3 and the thermal adhesive layer 5 may be one layer or two or more layers.
Moreover, you may have a printing layer in the surface on the opposite side to the heat bonding layer 5 side of the paper base material 3. FIG. It may further have an overprint layer on the print layer.

<PTP>
The PTP (press-through package) of the present invention comprises a container and a lid material, and the container is provided around a plurality of pocket portions for containing objects and an opening of the plurality of pocket portions, And a flange portion to be attached to the lid member,
The lid is made of the heat seal sheet of the present invention.

Hereinafter, a PTP of the present invention will be described by showing an embodiment with reference to the attached drawings. In the following, constituent elements corresponding to the above-described embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.
FIG. 2 is a cross-sectional view schematically showing a first embodiment of the PTP of the present invention.
The PTP 10 of the present embodiment includes a lid 11 and a container 13.
The lid member 11 is made of the heat seal sheet 1 shown in FIG. 1 and is disposed with the heat adhesive layer 5 side facing the container 13 side.
The container 13 includes a plurality of pocket portions 15 for accommodating the contained items 19 and a flange portion 17 provided around the openings of the plurality of pocket portions 15 and bonded to the lid member 11.
The surface of the flange portion 17 on the lid 11 side is flat, and is in close contact with the lid 11.
Each of the plurality of pocket portions 15 is formed so as to protrude from the surface of the flange portion 17 on the opposite side to the lid member 11 side, and has a concave portion for receiving the contained object 19 inside the protruding portion. The recess is opened in the surface of the flange portion 17 on the lid 11 side, and the opening is sealed by the lid 11 to form a space for accommodating the object 19 to be accommodated.

(Lid material)
As described above, as the heat seal sheet 1 constituting the lid 11, one having a degree of beating of the pulp constituting the base paper of the paper base 3 of 600 mL or less in standard freeness and 350 mL or less is used preferable. If the standard freeness is equal to or less than the upper limit value, the easy peel aptitude of the lid 11 is excellent.
As for the freeness of the said pulp, 50-500 mL is more preferable at the said irregular freeness, and 100-500 mL is still more preferable. If the anomalous freeness is within the above range, both excellent easy peel aptitude and press through aptitude can be achieved.

It is preferable that the heat sealing sheet 1 which comprises the cover material 11 is 18-50 g / m < ² > in basic weight of the paper base material 3. As shown in FIG. Preferred upper and lower limits of the basis weight of the paper substrate 3 are the same as described above. If the basis weight of the paper substrate 3 is equal to or more than the lower limit value of the above range, the strength which can withstand easy peel is easily obtained, and the breakage of the substrate at the time of peeling hardly occurs. If the basis weight of the paper substrate 3 is equal to or less than the upper limit value of the above range, the burst strength of the heat seal sheet 1 can be suppressed low, and the force necessary to push out the contained object 19 from the pocket portion 15 of the PTP 10 is Less, excellent in press-through suitability.

(container)
The material of the container 13 is not particularly limited, and various known materials can be used. For example, polypropylene resin, polyethylene terephthalate resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl chloride-polyvinylidene chloride composite resin, etc. may be mentioned.

  The container 13 can be manufactured, for example, by forming the plurality of pocket portions 15 in the above-described sheet of material. The method for forming the pocket portion 15 is not particularly limited, and examples thereof include a plug assist forming method, a vacuum forming method, a pressure forming method, a vacuum pressure forming method, a heat pressing method and the like.

In the PTP 10, the lid 11 and the flange portion 17 of the container 13 are preferably pasted together so that the lid 11 can be peeled off from the container 13 by the easy peel method.
Further, in this case, when the lid member 11 and the flange portion 17 are bonded together, the thermal adhesive layer 5 is a paper base in a portion in contact with the flange portion 17 when the lid member 11 is peeled by the easy peel method. It is preferable to carry out so that it may exfoliate from 3 and may remain in the flange part 17 side. If the thermal adhesive layer 5 remains on the flange 17 side at the time of peeling, the lid 11 is unlikely to be peeled off when the pocket 15 is pushed in and the contained object 19 is taken out.
In FIG. 3, an example of the state which peeled the cover material 11 from the container 13 by an easy-peel system is shown typically. In this example, when the lid 11 is peeled by the easy peel method, the thermal adhesive layer 5 is entirely peeled from the paper base 3 at the portion in contact with the flange portion 17 and remains on the flange portion 17 side. The portion in contact with the heat bonding layer 5 of the substrate 3 is exposed. In this case, since the thermal adhesive layer 5 is easily peeled off from the paper substrate 3, the substrate substrate 3 is pulled by the thermal adhesive layer 5 at the time of peeling of the lid 11, and substrate breakage and surface bumping of the surface occur. Hateful.
In FIG. 4, the other example of the state which peeled the cover material 11 from the container 13 by an easy-peel system is shown typically. In this example, when the lid member 11 is peeled by the easy peel method, delamination of the thermal adhesive layer 5 occurs in the portion in contact with the flange portion 17 and a part of the thermal adhesive layer 5 is the paper substrate 3 It is peeled off and remains on the flange portion 17 side, and the heat adhesive layer 5 remains on both the paper base 3 side and the flange portion 17 side. In this case, the thermal adhesive layer 5 remaining on the paper base 3 side can suppress the fluff of the paper base 3.
Whether the thermal adhesive layer 5 remains on the flange portion 17 side at the time of peeling depends on the amount of application of the polyacrylamide resin on the surface of the paper substrate 3 on the thermal adhesive layer 5 side, the lid 11 and the flange portion 17 The thermal bonding conditions (heating temperature, pressure, time, etc.), and the combination of the material of the thermal bonding layer 5 and the material of the adherend can be adjusted.

The peel strength between the lid 11 and the container 13 is not particularly limited. For example, the peel strength described below is preferably 0.060 to 0.700 kN / m, and 0.130 to 0.450 kN / m. Is more preferred. When the peel strength is equal to or more than the lower limit value of the above range, the lid member 11 is not easily peeled off when the pocket portion 15 is pushed in and the contained object 19 is taken out. If peeling strength is below the upper limit value of the said range, it can peel, without causing base-material destruction at the time of peeling in an easy-peel system.
Peeling strength: The ends of the lid 11 and container 13 of the PTP 10 cut to a width of 15 mm according to JIS P 8113: 2006 using a tensile tester (for example, Tensilon RTC-1250A, manufactured by Orientec Co., Ltd.) Peel strength measured by chucking and peeling speed 300 mm / min by 180 ° peel method.

(Production method)
The PTP 10 can be manufactured, for example, by housing the contained object 19 in the pocket portion 15 of the container 13 and overlapping and thermally bonding the lid member 11 to the container 13 so as to seal the opening of the pocket portion 15 . The thermocompression bonding conditions are not particularly limited.
The container 19 is not particularly limited, and examples thereof include medicines such as tablets, suppositories, capsules and the like, foods such as confectionery (such as candy and chocolate), cosmetics and the like.

(Action effect)
Conventionally, when the base material of the lid material is mainly made of paper, it has been difficult to achieve both excellent easy peel aptitude and press through aptitude.
In the PTP 10, since the lid 11 is the heat seal 1, it is possible to achieve both excellent easy peel aptitude and press through aptitude. For example, when peeling the lid 11 from the container 13, breakage of the paper base 3 and fuzzing of the surface hardly occur. Moreover, the pocket portion 15 can be pushed in with a sufficiently small force to break the lid member 11, and the object 19 can be taken out.
In addition, since the lid material is mainly made of paper, load on the human body when the lid material is accidentally consumed is less than that using the conventional aluminum foil. Further, the inclusion of foreign matter such as dust can be prevented by sealing with a heat sealing agent.
Therefore, PTP 10 is extremely useful in practice.

As mentioned above, although PTP of this invention was shown and demonstrated embodiment, this invention is not limited to the said embodiment. The configurations and combinations thereof in the above embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention.
For example, the heat seal sheet which comprises the cover material 11 should just be a heat seal sheet of this invention, and is not limited to the heat seal sheet 1. FIG.
In addition, at least one surface of the container 13 may have a print layer. It may further have an overprint layer on the print layer.

  The present invention will be specifically described by way of examples. The present invention is not limited to these examples.

Example 1
[Production of paper base material]
Mix 80% softwood bleached kraft pulp (NBKP) and 20% hardwood bleached kraft pulp (LBKP), and refine by DDR so that the irregular freeness (pulp collected 0.3 g / L) becomes 200 mL, pulp slurry I got Add 1% of sulfuric acid band and 1% of free circulation improver (trade name: Softool (registered trademark) 3503, manufactured by Yuka Sangyo Co., Ltd.) 0.07% of the pulp mass as the internal additive chemical to the pulp slurry. , Obtained the papermaking raw material. The papermaking raw material is made into a base paper by using a Fourdrinier paper machine to obtain a base paper, and then the following primer (A) is coated by the gate roll coater attached to the paper machine at a coated amount of 1.1 g after drying on one side. The paper is applied and dried so as to be 0.2 m / m ² (2.2 g / m ^{2 on} both sides), and is subjected to a smoothing treatment with an off-machine calendar to a paper with a basis weight of 30 g / m ² and a density of 1.15 g / cm ³ A substrate was obtained.
Primer (A): An aqueous solution of anionic polyacrylamide resin (weight average molecular weight 200,000) (Polymer Set (registered trademark) 512 manufactured by Arakawa Chemical Industries, Ltd.) was diluted with water to make the concentration of anionic polyacrylamide resin 10% by mass Adjusted).

[Production of heat seal sheet]
A coated amount of ethylene-vinyl acetate copolymer emulsion heat seal agent (trade name: EA-H700, manufactured by Toyo Ink Co., Ltd.) on one side of the paper substrate obtained above using a bar coater after drying It applied and dried so that it might be 3.0 g / m < ² >, the heat adhesion layer was formed, and the heat seal sheet was obtained.

[Production of PTP]
The following containers were prepared, and PTP was manufactured in the following procedures using the heat seal sheet obtained above as a lid material.
Container: A container for PTP made of polyvinyl chloride resin film with a thickness of 250 μm provided with 12 pockets (diameter: 6 × 2 rows) having a diameter of 10 mm and a depth of 5 mm.
Put the medicine (commercially available tablet-type cold medicine, tablet diameter 9.5 mm, thickness 4 mm) in the pocket of the above container, stack the lid material so that the heat adhesive layer side is in contact with the container, heat press Using the tester, thermocompression bonding was performed at 150 ° C., 3.0 kgf / cm ² for 1.1 seconds, to produce a PTP sealed with the above drug.

Example 2
A paper substrate, a heat seal sheet and a PTP were sequentially produced in the same manner as in Example 1 except that in the manufacture of the paper base of Example 1, the irregular freeness of pulp was changed to 460 mL.

Example 3
A paper substrate, a heat seal sheet and PTP were prepared in the same manner as in Example 2 except that the basis weight of the base paper was reduced and the basis weight of the paper substrate was 25 g / m ^{2 in} the production of the paper substrate of Example 2. It manufactured one by one.

Example 4
A paper substrate, a heat seal sheet and PTP were prepared in the same manner as in Example 2 except that in the production of the paper substrate of Example 2, the basis weight of the base paper was increased to set the basis weight of the paper substrate to 40 g / m ^2. It manufactured one by one.

Example 5
A paper substrate, a heat seal sheet and PTP in the same manner as in Example 2 except that in the production of the paper substrate of Example 2, the basis weight of the base paper was increased to set the basis weight of the paper substrate to 55 g / m ^2. Were manufactured sequentially.

Example 6
In the production of the paper substrate of Example 1, the coated amount of the primer (A) after drying on one side was 3.0 g / m ² (6.0 g / m ^{2 on} both sides), and the basis weight of the paper substrate was A paper substrate, a heat seal sheet and PTP were sequentially produced in the same manner as in Example 1 except that the basis weight of the base paper was reduced to be the same as in Example 1.

Example 7
In the production of the paper substrate of Example 1, the coated amount of the primer (A) after drying on one side is 0.4 g / m ² (0.8 g / m ^{2 on} both sides), and the basis weight of the paper substrate is A paper substrate, a heat seal sheet and PTP were sequentially produced in the same manner as in Example 1 except that the basis weight of the base paper was increased to be the same as in Example 1.

Example 8
[Production of paper base material]
Mix 80% softwood bleached kraft pulp (NBKP) and 20% hardwood bleached kraft pulp (LBKP), and refine by DDR so that the irregular freeness (pulp collected 0.3 g / L) becomes 200 mL, pulp slurry I got Add 1% of sulfuric acid band and 1% of free circulation improver (trade name: Softool (registered trademark) 3503, manufactured by Yuka Sangyo Co., Ltd.) 0.07% of the pulp mass as the internal additive chemical to the pulp slurry. , Obtained the papermaking raw material. The papermaking raw material is made into a base paper by using a Fourdrinier paper machine to obtain a base paper, and then the undercoating agent (A) is coated by the gate roll coater attached to the papermaking machine at a coated amount of 0.4 g / side after drying. A paper base of 30 g / m ^{2 in} basis weight and 1.05 g / cm ³ in density is applied and dried so as to be m ² (0.8 g / m ^{2 on} both sides) and smoothed with an off-machine calendar. I got the material.

[Production of heat seal sheet]
A coated amount of ethylene-vinyl acetate copolymer emulsion heat seal agent (trade name: EA-H700, manufactured by Toyo Ink Co., Ltd.) on one side of the paper substrate obtained above using a bar coater after drying The heat-adhesive layer was formed by coating and drying so as to be 1.4 g / m ² to obtain a heat seal sheet.

[Production of PTP]
The following containers were prepared, and PTP was manufactured in the following procedures using the heat seal sheet obtained above as a lid material.
Container: A container for PTP made of polyvinyl chloride resin film with a thickness of 250 μm provided with 12 pockets (diameter: 6 × 2 rows) having a diameter of 10 mm and a depth of 5 mm.
Put the medicine (commercially available tablet-type cold medicine, tablet diameter 9.5 mm, thickness 4 mm) in the pocket of the above container, stack the lid material so that the heat adhesive layer side is in contact with the container, heat press Using the tester, thermocompression bonding was performed at 150 ° C., 3.0 kgf / cm ² for 1.1 seconds, to produce a PTP sealed with the above drug.

Example 9
A paper substrate, a heat seal sheet and a PTP were sequentially produced in the same manner as in Example 8 except that in the manufacture of the paper base of Example 8, the irregular freeness of pulp was changed to 460 mL.

Example 10
A paper substrate, a heat seal sheet and PTP were prepared in the same manner as in Example 9 except that the basis weight of the base paper was reduced and the basis weight of the paper substrate was 25 g / m ^{2 in} the production of the paper substrate of Example 9. It manufactured one by one.

Example 11
A paper substrate, a heat seal sheet and PTP were prepared in the same manner as in Example 9 except that in the production of the paper substrate of Example 9, the basis weight of the base paper was increased to set the basis weight of the paper substrate to 40 g / m ^2. It manufactured one by one.

Example 12
A paper substrate, a heat seal sheet and PTP in the same manner as in Example 9 except that in the production of the paper substrate of Example 9, the basis weight of the base paper was increased to set the basis weight of the paper substrate to 55 g / m ^2. Were manufactured sequentially.

Comparative Example 1
A paper substrate, a heat seal sheet, and a PTP were sequentially produced in the same manner as in Example 1 except that in the production of the paper base of Example 1, the irregular freeness of pulp was 770 mL (generally, 380 mL as freeness).

Comparative Example 2
Example 1 and Example 1 with the exception that in the production of the paper substrate of Example 1 the primer (A) was not applied and the basis weight of the base paper was increased such that the basis weight of the paper substrate was the same as in Example 1. In the same manner, a paper substrate, a heat seal sheet and PTP were sequentially produced.

Comparative Example 3
In the manufacture of the paper substrate of Example 1, the primer coating amount after drying of one side of (A) and ^{0.05g / m 2 (0.1g / m} 2 on both sides), the basis weight of the paper substrate A paper substrate, a heat seal sheet and PTP were sequentially produced in the same manner as in Example 1 except that the basis weight of the base paper was increased to be the same as in Example 1.

Comparative Example 4
A paper substrate, a heat seal sheet and PTP in the same manner as in Example 2 except that the basis weight of the base paper was reduced and the basis weight of the paper substrate was 14 g / m ^{2 in} the production of the paper substrate of Example 2. Were manufactured sequentially.

Comparative Example 5
In the production of the paper substrate of Example 1, the following primer (B) was used instead of the primer (A), and the coated amount after drying on one side was 0.4 g / m ² (0.8 g / m ^{2 on} both sides) A paper substrate, a heat seal sheet and a PTP are sequentially produced in the same manner as in Example 1 except that m ² ) and the basis weight of the base paper are increased so that the basis weight of the paper base becomes the same as Example 1. did.
Primer (B): 4% by mass aqueous solution of polyvinyl alcohol (trade name: PVA117, manufactured by Kuraray Co., Ltd.).

Comparative Example 6
In the preparation of the paper substrate of Example 1, the following primer (C) was used instead of the primer (A), and the coated amount after drying on one side was 0.8 g / m ² (1.6 g on both sides A paper substrate, a heat seal sheet and a PTP are sequentially produced in the same manner as in Example 1 except that m ² ) and the basis weight of the base paper are increased so that the basis weight of the paper base becomes the same as Example 1. did.
Primer (C): 8% by mass aqueous solution of hydrophobized starch (trade name: GRS-T110, manufactured by Oji Cornstarch Co., Ltd.).

Table 1 shows the irregular freeness of pulp in each of Examples 1 to 12 and Comparative Examples 1 to 6, the basis weight of base paper, the type of primer applied to base paper and the coated amount per one side, and the basis weight of paper base The density is shown respectively.
The coating amount per one surface (coating amount after drying) of the primer in each example is equal to the coating amount as a water-soluble polymer (anionic polyacrylamide resin, polyvinyl alcohol or hydrophobized starch) in the primer. .

<Evaluation>
The following evaluation was performed about the heat seal sheet (lid material) and PTP which were obtained in Examples 1-12 and Comparative Examples 1-6, respectively, and the result was shown in Table 2.

[Measurement of burst strength]
The burst strength (kPa) of the heat seal sheet of each example was measured according to ISO 2758 using a burst tester (model: MD 200, manufactured by Kumagaya Riki Kogyo Co., Ltd.).

[Measurement of peeling strength and evaluation of the state of substrate breakage]
The heat seal sheet of each example and a polyvinyl chloride resin film (pocket part not formed) used for the container are stacked so that the surface on the heat adhesive layer side of the heat seal sheet is in contact with the polyvinyl chloride resin film, A thermo-compression-bonding material was produced under the thermo-compression bonding conditions of 150 ° C., 3.0 kgf / cm ² , and 1.1 seconds using a heat press tester. Next, this thermocompression-bonding material was cut into a width of 15 mm to prepare a peel strength measurement sample.
The peel strength (kN / m) of the obtained sample was measured using a tensile tester (type: TENSILON RTC-1250A, manufactured by ORIENTEC Co., Ltd.) according to JIS P 8113: 2006, using the polyvinyl chloride resin film of the sample. The end portions of each of the heat seal sheets were chucked and measured at a peeling speed of 300 mm / min by 180 ° peel method.
Moreover, in the case of the measurement of peeling strength, the state of the base-material destruction of the heat seal sheet was visually confirmed, and the following references | standards evaluated.
(Evaluation criteria for the state of substrate failure during peeling test)
:: substrate failure did not occur.
Δ: The heat seal sheet could be peeled off, but adhesion of a piece of paper or fluff was observed on the polyvinyl chloride resin film.
X: Substrate breakage occurred.

[Measurement of drug pushing force]
The heat seal sheet of each example and a container polyvinyl chloride resin film (pockets are not formed) having a hole of 10 mm in diameter previously formed are in contact with the polyvinyl chloride resin film on the heat seal layer side of the heat seal sheet. As it piles up, a thermocompression-bonding thing was created on thermocompression-bonding conditions of 150 degreeC, 3.0 kgf / cm < ² >, and 1.1 second using a heat press tester.
Next, using a texture analyzer (model: TA-XT plus, made by Eko Seiki Co., Ltd.), a polycarbonate resin plate (10 cm × 10 cm, thickness 30 mm) having a diameter of 20 mm and a hole formed therein is circled with a hole center It was set to overlap with the center of the columnar probe.
Next, place the polyvinyl chloride resin film on top of the resin plate so that the centers of the holes in the polyvinyl chloride resin film of the thermocompression-bonded product come to the center of the holes of the resin plate. Set to
Next, affix the medicine (commercial tablet type cold medicine, tablet diameter 9.5 mm, thickness 4 mm) to the tip of the cylindrical probe of the texture analyzer and lower the speed of the probe at a rate of 300 mm / min. The force applied to the force applied to the extrusion (drug extrusion force) (N) was measured. The drug extruding force is the force required for the drug at the tip of the probe to break through the heat seal sheet of the thermocompression-bonding material and be pushed out to the lower side of the thermocompression-bonding material. . In addition, it is thought that it is about 18 N or less as a force which can be pushed out without force.

[Sensory evaluation of press-through aptitude and easy-peel aptitude]
With respect to the obtained PTP, the press-through property and the easy peelability were practically evaluated on the basis of the following criteria.
(Press through aptitude)
○: The drug was extruded without problems.
○ ': It took a little big power to push out the medicine.
Δ: A large force was required to push out the drug.
X: The lid material was too strong and the drug could not be extruded. Or, the lid was peeled off before pushing out the medicine.
(Easy peel aptitude)
○: The lid material was easy to peel without problems.
Fair: Easy peeling of the lid material, but adhesion of a piece of paper or fluff was observed on the container side.
X: Substrate breakage occurred and easy peeling was not possible.

  In Table 2, "-" in the column of peel strength indicates that the peel strength could not be measured because the substrate was broken.

As shown in the above results, the heat seal sheets of Examples 1 to 12 had small peel strength in the peel test. In addition, no substrate destruction was observed at the time of the peeling test, and the same results were obtained in the actual sensory evaluation performed for PTP. From these results, it was confirmed that the easy peel aptitude was excellent.
In particular, the heat seal sheets of Examples 1 to 3, 6, 8 to 10, 12 had a small drug extrusion force. The drug pushing force roughly corresponded to the burst strength. Also, in the actual sensory evaluation conducted for PTP, the drug was successfully extruded. From these results, it has been confirmed that the combination has excellent easy peel aptitude and press-through aptitude.

  On the other hand, in the heat seal sheets of Comparative Examples 1 to 6, in the peel test, the peel strength could not be measured or the peel strength was larger than those of Examples 1 to 12 even though measurement could be made. Moreover, base material destruction, fuzzing of the surface, and peeling of a piece of paper were observed during the peeling test, and the same results were obtained in the actual sensory evaluation performed for PTP.

1 heat seal sheet 3 paper base 5 heat adhesive layer 10 PTP (press through package)
11 lid material 13 container 15 pocket portion 17 flange portion 19 contained material

Claims (8)

A paper base and a heat adhesive layer laminated on one side of the paper base,
The paper base includes a base paper made of pulp, and a coating layer containing a polyacrylamide resin provided on at least the surface on the heat adhesive layer side of the base paper.
The freeness of the pulp measured according to JIS P 8121-2: 2012 is 600 mL or less, and the following irregular freeness is 50 to 500 mL ,
The content of the polyacrylamide resin in the coating layer provided on the surface of the heat adhesive layer side is 0.1 to 10.0 g / m ² ,
The heat seal sheet, wherein the basis weight of the paper substrate is 18 g / m ² or more.
Anomalous freeness: Measured according to JIS P 8121-2: 2012 except that the solid content concentration of the pulp suspension was changed from 0.30% ± 0.01% to 0.030% ± 0.001% Freeness. A paper base and a heat adhesive layer laminated on one side of the paper base,
The paper base includes a base paper made of pulp, and a coating layer containing a polyacrylamide resin provided on at least the surface on the heat adhesive layer side of the base paper.
Ri irregular freeness is 50~500mL der of the following of the pulp,
The content of the polyacrylamide resin in the coating layer provided on the surface of the heat adhesive layer side is 0.1 to 10.0 g / m ² ,
The heat seal sheet, wherein the basis weight of the paper substrate is 18 g / m ² or more .
Anomalous freeness: Measured according to JIS P 8121-2: 2012 except that the solid content concentration of the pulp suspension was changed from 0.30% ± 0.01% to 0.030% ± 0.001% Freeness. The heat seal sheet according to claim 1, wherein a basis weight of the paper base is 50 g / m ² or less.   The heat seal sheet according to any one of claims 1 to 3, which is a lid material for a press-through package. A method for producing a heat seal sheet comprising a paper substrate and a heat adhesive layer laminated on one side of the paper substrate,
Applying a coating solution containing a polyacrylamide resin to at least one surface of a base paper made of pulp, and drying to form a coating layer to obtain a paper substrate;
Laminating a thermal adhesive layer on the surface of the paper substrate on which the coating layer is provided;
Have
The freeness of the pulp measured according to JIS P 8121-2: 2012 is 600 mL or less, and the following irregular freeness is 50 to 500 mL ,
The application amount of the coating liquid applied to the side of the base paper on which the heat adhesive layer is laminated is 0.1 to 10.0 g / m ² in terms of the amount of the polyacrylamide resin,
The basis weight of the said paper base material is 18 g / m < ² > or more, The manufacturing method of the heat seal sheet characterized by the above-mentioned.
Anomalous freeness: Measured according to JIS P 8121-2: 2012 except that the solid content concentration of the pulp suspension was changed from 0.30% ± 0.01% to 0.030% ± 0.001% Freeness.   A method for producing a heat seal sheet comprising a paper substrate and a heat adhesive layer laminated on one side of the paper substrate,
  Applying a coating solution containing a polyacrylamide resin to at least one surface of a base paper made of pulp, and drying to form a coating layer to obtain a paper substrate;
  Laminating a thermal adhesive layer on the surface of the paper substrate on which the coating layer is provided;
Have
  The following irregularity freeness of the said pulp is 50-500 mL,
  The application amount of the coating solution applied to the side of the base paper on which the heat adhesive layer is laminated is 0.1 to 10.0 g / m in terms of the amount of the polyacrylamide resin. ² And
  The basis weight of the paper base is 18 g / m ² The manufacturing method of the heat seal sheet characterized by the above.
  Anomalous freeness: Measured according to JIS P 8121-2: 2012 except that the solid content concentration of the pulp suspension was changed from 0.30% ± 0.01% to 0.030% ± 0.001% Freeness. A press comprising a container and a lid member, wherein the container is provided with a plurality of pocket portions for containing objects and a flange portion provided around the openings of the plurality of pocket portions and bonded to the lid member. Through packaging,
The press-through package body, wherein the lid member comprises the heat seal sheet according to any one of claims 1 to 4. When the lid material can be peeled off from the container by the easy peel method, and when the lid member is peeled by the easy peel method, the thermal adhesive layer peels off from the paper base at a portion in contact with the flange portion The press-through package according to claim 7 , wherein the lid member and the flange portion are pasted together so as to remain on the flange portion side.

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