JP6173517B1 - Adhesive, laminate and PTP package - Google Patents

Abstract

Provided is an adhesive that has high adhesive strength and does not cause blocking even when bonded at a higher temperature at a lower temperature than conventional ones. An adhesive of the present invention is an adhesive constituting a surface layer on one side of a lid for PTP packaging, and has a Tg of −20 ° C. to −10 ° C. The mass of the polyester resin, the vinyl acetate resin, and the silica particles is 90% or more of the total mass, including the vinyl chloride resin and the silica particles, and the polyester resin is contained. The amount is 40% or more and 50% or less of the total mass, the content of the vinyl chloride resin is 40% or more and 45% or less of the total mass, and the content of the silica particles is 5% of the total mass. It is 10% or less. [Selection] Figure 1

Description

  The present invention relates to an adhesive, a laminate, and a PTP package.

  A PTP packaging material frequently used for packaging pharmaceutical products and the like is composed of two parts, a container part for storing contents and a lid member for sealing the container part. A container part is comprised by the processing molded object of the plastic sheet which shape | molded the pocket. The lid material is configured by providing a printing layer on one or both surfaces of a metal foil, particularly an aluminum foil, and further providing a heat-resistant coating layer and a heat sealing adhesive layer on each surface thereon.

  As a plastic sheet forming the container body, a vinyl chloride resin sheet has been used for a long time because of its excellent processability. However, in recent years, a polypropylene sheet is often used because it is excellent in moisture resistance and inexpensive. It has become to.

  On the other hand, as the base material of the lid material, metal foil, particularly aluminum foil, is usually used because of the usage method of PTP packaging in which the lid material is ruptured and the contents are taken out.

  The above-mentioned lid material usually has characters and designs printed on both sides or one side of a metal foil, particularly an aluminum foil base material, and further, on one side (the outer side) is colorless or colored transparent. By applying a special heat-resistant coating, a heat-resistant coating layer is provided to protect the printed layer of characters and designs during heat sealing, and the opposite surface (the surface to be bonded) is heated in a plastic container In order to heat seal by pressure bonding, it is manufactured by applying a colorless or colored heat sealable adhesive to form a heat sealable adhesive layer.

  The contents are filled and sealed in the packaging operation after the contents are stored in a processed molded body of a vinyl chloride resin sheet or a polypropylene sheet provided with pockets (dents) to be the above-mentioned containers, and then the above-mentioned contents on the opening side. The aluminum foil lid is laminated so that the heat-sealing adhesive layer is in contact with it, and heated and pressed with a heat sealing roll from the surface of the lid provided with the heat-resistant coating layer. This is accomplished by heat fusing the part.

  The surface of the heat sealing roll is usually embossed in a grid pattern, and the heat and pressure conditions vary depending on the type of laminated material, but the heat sealing temperature is between 120 and 280 ° C. The heat sealing pressure is often set to 0.1 to 0.6 MPa.

JP 2005-138848 A Japanese Patent Laying-Open No. 2015-93727

  In recent years, PTP filling machines have been accelerated in filling speed for the purpose of improving packaging efficiency, and 6000 tablet high-speed packaging machines and 8000 tablet high-speed packaging machines are used in Japan. Since the time required for the heat sealing roll to come into contact with the cover material is shortened due to the increase in speed, in order to provide the amount of heat necessary for bonding the sheet and the cover material, the temperature of the heat sealing roll must be set higher than before. Must be set.

  Also, barcode display is obligatory for the PTP sheet, and in order to perform barcode printing, it is necessary to perform white printing on the entire sheet. Therefore, the thermal conductivity of the lid material is also lowered by the increase in the number of laminated lid materials and the titanium oxide contained in the white ink. Therefore, when the white printing layer is added, in order to give the heat sealing adhesive layer the necessary amount of heat, it is necessary to increase the temperature of the heat sealing roll or reduce the filling speed.

  However, the temperature of the heat sealing roll cannot be a temperature exceeding the heat resistance of the heat-resistant coating agent. Also, reducing the filling speed is inefficient, resulting in decreased productivity. Although a method of lowering the bonding temperature of the heat sealing resin layer is conceivable, the bonding strength cannot be maintained by simply lowering the bonding temperature due to the effect of embossing. Further, if the material is changed in order to lower the temperature at which the heat sealing resin layer can be bonded, blocking may occur when only the lid material is wound and stored.

  In view of the above problems, an object of the present invention is to provide an adhesive that has high adhesive strength and does not cause blocking even if it is bonded at a lower temperature than conventional ones.

  The adhesive of the present invention is an adhesive constituting a surface layer on one side of a lid for PTP packaging, and a polyester resin having a Tg of −20 ° C. or higher and −10 ° C. or lower; The total mass of the polyester resin, the vinyl chloride resin, and the silica particles is 90% or more of the total mass, including the resin and silica particles. The content of the vinyl chloride resin is 40% or more and 45% or less of the total mass, and the content of the silica particles is 5% or more and 10% or less of the total mass. It has the composition which is. With such a configuration, sufficient bonding strength can be obtained and blocking can be suppressed even when bonding is performed at a lower temperature than in conventional high-speed bonding with PTP filling. Here, the vinyl acetate resin is obtained by copolymerizing a vinyl chloride monomer, a fatty acid vinyl monomer, and a monomer having an unsaturated carbon-carbon double bond in one molecule and having a functional group. Here, examples of the functional group in the monomer having a carbon-carbon unsaturated double bond in one molecule and having a functional group include a hydroxyl group, a carboxyl group, an isocyano group, and an epoxy group. For example, vinyl chloride vinyl acetate copolymer resin is a typical one.

  The vinyl chloride resin is preferably an acid-modified resin.

  The silica particles are preferably hydrophobic silica particles.

  The average particle diameter of the silica particles is preferably 2 μm or more and 10 μm or less.

  The laminate of the present invention includes a base material made of a metal foil, the above-described adhesive placed on one surface of the base material, and a print receiving layer provided on the other surface of the base material. It has.

  The PTP package of the present invention has a container made of a vinyl chloride sheet provided with a plurality of depressions, and a lid made of the above laminate, and the contents are stored in the depressions. The material has sealed the said hollow, and the part adhere | attached on the said container among the said cover materials has a some recessed part.

  The adhesive of the present invention can exhibit sufficient adhesive strength even at low temperatures and under embossed bonding conditions, and when the surface layer on one side of the lid material is constructed, the adhesive roll of the lid material alone is blocking. Occurrence is suppressed.

It is typical sectional drawing of the cover material for PTP packaging which concerns on embodiment. It is a typical sectional view of PTP packaging concerning an embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

(Embodiment 1)
FIG. 1 shows a cross section of the cover material for PTP packaging according to the first embodiment. The cover (laminated body) 30 is provided with the adhesive layer 10 on one surface of the base material layer 20, and the print receiving layer 21 and the heat resistant coating layer 22 covering the print receiving layer 21 on the other surface. It has been. The surface of the print receiving layer 21 is printed with a barcode 25 or the like, and the heat resistant coating layer 22 also covers the print 25.

  The base material layer 20 is made of a metal foil or a plastic film, and it is particularly preferable to use an aluminum foil. The print receptive layer 21 includes a pigment and a filler. As a binder, a vinyl chloride resin, a nitrocellulose resin, an epoxy resin, an acrylic resin, a urethane resin, a melamine resin, an ester resin, or the like is used. Alternatively, a mixture of these may be used, but it is particularly preferable to use a vinyl chloride resin. The heat-resistant coating layer 22 can be used by including an epoxy resin, a nitrocellulose resin, a cellulose acetate resin, an acrylic resin, an ester resin, a melamine resin or a mixture thereof as a binder. Or what mixed nitrocellulose resin and melamine resin is preferable. The adhesive layer 10 will be described later.

  FIG. 2 shows a cross section of the PTP package according to this embodiment. The PTP package 100 of the present embodiment has a container sheet 1 and a lid member 30 forming a container main body, and the container sheet 1 is formed with a plurality of depressions 1a and 1a. The other part is a flange portion 1b bonded to the lid member 30. The contents (objects to be stored) 2 are stored in the recesses 1a and 1a, and the lid member 30 seals the recesses 1a and 1a. In the bonding portion between the flange portion 1b and the lid member 30, the lid member 30 has a so-called embossed shape in which a plurality of recesses are formed. This is because the surface of the thermocompression-bonding roll is embossed to form an embossed shape. When the container sheet 1 and the lid member 30 are bonded together, This is to prevent the air from getting caught in the seal part by creating a way for the air to escape to the outside.

-Examination of adhesive layer-
The adhesive layer that can cope with the high filling speed in PTP packaging was examined. The adhesive layer was examined with the configuration of the lid member 30 shown in FIG. Here, the base material layer 20 is an aluminum foil that is generally used. The container sheet on the other side to be bonded was made of polyvinyl chloride. Note that the bonding condition was the temperature of the heat sealing roll under the conventional low speed condition, and the bonding speed was a high speed condition faster than the conventional one. Evaluation is sealing property (peeling test and leak test: the leak test is to see if the space between the container sheet and the lid 30 is peeled off under the reduced pressure condition of −68 kPa × 5 min). Evaluation and blocking property evaluation (a plurality of lid materials are overlapped with an adhesive layer and a heat-resistant coating layer, applied at a pressure of 0.196 MPa, left at 40 ° C. for 7 days, and then peeled off). It was.

  The contents stored in the PTP package are medicines, foods, and the like, which are put into the body by human beings. Therefore, the adhesive for the lid material that contacts the contents must be harmless to the human body. In addition, it is not preferable that the adhesive of the lid material contacting the contents affects the contents such as reacting with the constituents of the contents, changing the constituents, or extracting the constituents. . Therefore, a mixture of a polyester resin and a vinyl acetate resin is most preferable as an adhesive for the lid material that comes into contact with the contents.

  The adhesive before the filling speed is increased in PTP packaging is a mixture of polyester resin A (Tg of 7 ° C.) and vinyl acetate resin in a mass ratio of 4: 6 (conventional example). .

  In the conventional example, blocking did not occur. However, when it was bonded to the container film at high speed and low temperature, it was found to be NG in the leak test, and it was found that the adhesive was not sufficiently melted.

  Therefore, a urethane resin having high adhesiveness to the metal foil at a low heat amount is added so that the content can be dealt with without affecting the contents (polymer type, amount). We examined by reducing both of the vinyl chloride resin. Specifically, polyester resin A: vinyl acetate resin: urethane resin = 35: 50: 15 (Comparative Example 1).

  In Comparative Example 1, blocking did not occur. However, when bonded to the container film at a high speed and a low temperature, the adhesive strength was insufficient and the result was NG. In Comparative Example 1, when bonding was performed with a roll that was not embossed in thermocompression bonding, the adhesive strength was sufficient, but when bonding was performed with a roll that was embossed, the adhesive strength was Became NG. In actual PTP packaging, since the emboss seal is performed, it is necessary that the adhesive strength at the emboss seal is sufficiently large.

  In Comparative Example 1, since the adhesive strength of the embossed seal was low, it was considered that the flowability of the molten resin at the time of sealing was high, and it was considered to add amorphous silica particles to reduce the flowability. The amount of urethane resin relative to the entire adhesive layer (including silica) was the same as in Comparative Example 1, and both the polyester resin A and the vinyl acetate resin were reduced by the same amount as the amount of silica added. Specifically, polyester resin A: vinyl chloride resin: urethane resin: amorphous silica = 30: 45: 15: 10 (Comparative Example 2).

  Although the evaluation of the blocking property was not performed, it is considered that blocking is much more difficult than Comparative Example 1 because silica is added. However, Comparative Example 2 was NG in the leak test, and the adhesive strength was insufficient. When the embossed seal was observed, it was estimated that the flowability of the adhesive was still high, but it was judged that silica that does not contribute to the adhesive strength could not be added any further, and the adhesive strength at low heat by adding urethane resin. We finished study of improvement.

  As a next study, the physical properties of the polyester resin were changed instead of adding another resin. Specifically, Tg was lowered and the amount was increased with respect to vinyl chloride resin. However, when the amount of the polyester resin B (Tg: −15 ° C.) having a low Tg is increased, blocking becomes easy, so amorphous silica was added. Specifically, polyester resin B: vinyl acetate resin: amorphous silica = 52: 36: 12 (Comparative Example 3).

  When the lid material of Comparative Example 3 was evaluated, blocking occurred, and thus the adhesive strength was not evaluated. In Comparative Example 3, amorphous silica particles were added as much as 12% by mass, but blocking occurred, so the amount of polyester resin B was reduced and the amount of vinyl acetate resin was increased. Moreover, examination which reduces the amount of silica which does not contribute to adhesive force was performed. Specifically, hydrophobized silica particles having better dispersibility in the resin than amorphous silica particles were used, and polyester resin B: vinyl chloride resin: hydrophobized silica = 48: 44: 8 (Example 1) ).

  In the lid material provided with the adhesive layer having the composition of Example 1, no blocking occurred in the blocking property evaluation, the adhesive strength of the embossed seal was sufficiently large, and no leak occurred in the leak test. Therefore, the adhesive layer of Example 1 is suitable for the use of a PTP packaging lid material that performs high-speed filling. Further, the adhesive layer having the composition of Example 2 (polyester resin B: vinyl acetate resin: acrylic resin: hydrophobic silica = 44: 43: 6: 7) in which the amount of the polyester resin B was reduced and a small amount of acrylic resin was added. Also, the lid material provided with no blocking, the adhesive strength of the embossed seal was sufficiently large, and no leak occurred in the leak test.

  As described above, the adhesive layers of Examples 1 and 2 are excellent in both non-blocking properties and sealing properties, and are suitable as adhesive layers for PTP packaging lid materials. As a result of various studies, it has been found that the Tg of the polyester resin is excellent in both non-blocking properties and sealing properties when the Tg is −20 ° C. or higher and −10 ° C. or lower. The total mass of the polyester resin, the vinyl chloride resin, and the silica particles is 90% or more of the total mass, and the content of the polyester resin is 40% or more and 50% or less of the total mass. If the content of the vinyl chloride resin is 40% or more and 45% or less of the total mass and the content of the silica particles is 5% or more and 10% or less of the total mass, both non-blocking and sealing properties are excellent. Turned out to be.

(Other embodiments)
The above-described embodiment is an exemplification of the present invention, and the present invention is not limited to these examples, and these examples may be combined or partially replaced with known techniques, common techniques, and known techniques. Also, modified inventions easily conceived by those skilled in the art are included in the present invention.

  The polyester resin is preferably an amorphous polyester resin from the viewpoint of solubility in an organic solvent. The vinyl chloride resin is preferably acid-modified in terms of adhesion to the metal foil, and the acid modification rate is preferably 0.1% to 1.5%. As the acid for acid modification, dicarboxylic acid, maleic acid and the like are preferable. The composition of the vinyl chloride resin is preferably 70 to 86% vinyl chloride and 10 to 30% vinyl acetate. The average particle diameter of the silica particles is preferably 2 μm to 10 μm from the viewpoint of non-blocking properties.

  You may add resin other than an acrylic resin, for example, polyester resin, urethane resin, etc. from which Tg differs.

DESCRIPTION OF SYMBOLS 1 Sheet | seat for containers 1a Dimple 2 Contents 10 Adhesive layer 20 Base material 21 Print receiving layer 30 Lid (laminated body)
100 PTP package

Claims (6)

An adhesive constituting a surface layer on one side of the lid for PTP packaging,
A polyester resin having a Tg of −20 ° C. or more and −10 ° C. or less, a vinyl acetate resin, and silica particles;
The total mass of the polyester resin, the vinyl chloride resin, and the silica particles is 90% or more of the total mass,
The content of the polyester resin is 40% or more and 50% or less of the total mass,
The content of the vinyl chloride resin is 40% or more and 45% or less of the total mass,
Content of the said silica particle is an adhesive agent which is 5% or more and 10% or less of the whole mass.   The adhesive according to claim 1, wherein the vinyl chloride resin is an acid-modified resin.   The adhesive according to claim 1, wherein the silica particles are hydrophobic silica particles.   The adhesive as described in any one of Claim 1 to 3 whose average particle diameter of the said silica particle is 2 micrometers or more and 10 micrometers or less.   The laminated body provided with the base material which consists of metal foil, and the adhesive agent described in any one of Claim 1 to 4 mounted in the one surface of the said base material. A container made of a vinyl chloride sheet provided with a plurality of depressions, and a lid made of a laminate according to claim 5;
Contents are stored in the recess, the lid material seals the recess, and a portion of the lid material bonded to the container has a plurality of recesses, PTP package .

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