JP6007548B2 - Lid material and hermetically sealed container sealed using the lid material - Google Patents

Description

  The present invention is a lid that is mainly applied to sealed containers for foods, and more specifically, is a lid that is applied to sealed containers such as yogurt, jelly, pudding, jam and the like, and has a content adhesion preventing property. It is about.

  Currently, cup-shaped containers are used as sealed containers such as yogurt, jelly, pudding, jam and the like, and the flanges of the container bodies are sealed by heat-sealing a lid material and commercialized. As this type of cover material, for example, in general, there are many materials in which an aluminum foil is bonded to one surface of a base material layer, and a thermal adhesive layer is provided on the aluminum foil surface side through an adhesive layer.

  Such a lid material is required to have a good sealing property with the container body, a sealing property, and an appropriate easy peel property for opening, and at the same time, the non-adhesiveness of the contents to the inner surface of the lid material is desired. Yes. Conventionally, as for a cover material, as shown in FIG. 6, the contents may adhere to the back surface of the cover material 1. FIG. 6 shows an example. For example, when yogurt 11 having low viscosity is stored in the container body 30, the yogurt 11 may adhere to the inner surface of the lid 1. If the contents are attached, clothes, fingers, or the surrounding area may be soiled when opened, and waste due to loss of the contents may occur, or it may take time and effort to peel off the contents. The disadvantage is caused.

  As a method for preventing adhesion, for example, there is a method of imparting water repellency to the surface of the thermal adhesive layer of the lid. This is a method using a fluorochemical having water repellency. The fluorine-based drug exhibits an anti-adhesion effect, but a drug having a C8 main chain with a small surface energy may have a high residual rate in the body, and therefore has a C6 main chain with slightly poor water repellency. May be used. However, a drug having a main chain at C6 has a defect that it has no effect of preventing the adhesion of contents because of poor water repellency.

  Further, as another method for preventing adhesion, in the lid member in which the base material layer, the thermal adhesive layer, and the content adhesion preventing layer are sequentially laminated, wax and inorganic powder in the content adhesion preventing layer, that is, There is also a proposal characterized by containing a filler composed of hydrophobic fine particles (Patent Document 1).

  Patent Document 1 proposes an adhesion prevention effect by adding a filler to the wax, but the problem that the adhesion prevention effect cannot be stably exhibited because the filler is not uniformly exposed on the surface of the adhesion prevention layer. There is.

  Further, as another method, a lid material in which a base material layer and a thermal adhesive layer are laminated, and hydrophobic oxide fine particles having an average primary particle diameter of 3 to 100 nm are attached to the thermal adhesive layer, and the hydrophobic oxidation is performed. There is also a proposal characterized in that the fine particles form a porous layer having a three-dimensional network structure (Patent Document 2).

  Although the proposal of Patent Document 2 has an adhesion preventing effect, there is a problem that the adhesion with the thermal adhesive layer is weak, and it is easy to peel off. Therefore, since the mechanical strength is weak, there is a problem in that the adhesion preventing effect varies.

Another method is a lid member in which a base material layer, a hot-melt adhesive layer, and an adhesion prevention layer are laminated in order, and the adhesion prevention layer is a wet type having an average particle size of 2.0 to 7.0 μm. There is also a proposal characterized in that it is a hydrophobic wet silica particle obtained by hydrophobizing silica, and its adhesion amount is 0.1 to 1.0 g / m ² (Patent Document 3).

  The proposal of Patent Document 3 has an adhesion preventing effect, but has a problem that the adhesiveness between the hot melt layer and the hydrophobic wet silica is weak, the mechanical strength is weak, and it is easy to peel off.

  When the lid material as described above is mixed in the thermal adhesive layer, the adhesion preventing effect varies. In addition, even if hydrophobic oxide fine particles are arranged on the surface of the thermal adhesive layer to exhibit an anti-adhesion effect, there is a problem that the adhesion to the thermal adhesive layer is weak, the mechanical strength is weak, and it is easy to peel off and fall off. .

  Therefore, there is a demand for a lid member provided with a content adhesion preventing layer having mechanical strength.

JP 2009-73523 A Japanese Patent No. 4348401 Japanese Patent No. 4668352

  In view of the above problems, an object of the present invention is to provide a lid member that has good sealing performance and content adhesion prevention. It is an object of the present invention to provide a lid material that is particularly strong in mechanical strength and has productivity.

  In order to solve the above problems, the inventors have intensively studied and completed the present invention.

The invention according to claim 1 of the present invention is a lid made of a laminate in which at least a base material layer, a thermal adhesive layer, and a content adhesion preventing layer are sequentially laminated,
The content adhesion preventing layer is composed of spherical particles, hydrophobic oxide fine particles, and a binder resin ,
The binder resin is composed of particles having an average particle size in the range of 1 to 5 μm, and the resin particles have spherical particles and hydrophobic oxide fine particles fixed on the surface while maintaining the particle shape. It is a characteristic lid material.

  The invention according to claim 2 of the present invention is the lid according to claim 1, wherein the spherical particles are a silicone resin having an average particle diameter of 3 to 30 μm.

  The invention according to claim 3 of the present invention is the lid according to claim 1 or 2, wherein the hydrophobic oxide fine particles are hydrophobic silica having an average particle diameter of 5 to 20 nm.

  The invention according to claim 4 of the present invention is characterized in that the binder resin is any one of polyethylene, polypropylene, polyester, ethylene-vinyl acetate copolymer, acrylic, styrene-butadiene rubber, or a mixture thereof. It is a lid | cover material of any one of Claims 1-3.

The invention according to claim 5 of the present invention is characterized in that the center line average roughness Ra of the surface of the content adhesion preventing layer is Ra> 4 μm, according to any one of claims 1 to 4. It is a lid.

The invention according to claim 6 of the present invention is the lid according to claim 3, wherein the hydrophobic silica has a trimethylsilyl group.

The invention according to claim 7 of the present invention is characterized in that an aluminum layer is laminated between the base material layer and the thermal adhesive layer, and the lid material according to any one of claims 1 to 6 It is.

The invention according to claim 8 of the present invention is a sealed container characterized by being sealed using the lid material according to any one of claims 1 to 7 .

  The content adhesion preventing layer of the present invention is composed of spherical particles that make the surface of the content adhesion preventing layer uneven, a hydrophobic oxide fine particle having water repellency, and a binder resin that provides adhesion to the thermal adhesive layer. It is a lid material that has a content adhesion preventing property and excellent mechanical strength. Moreover, a sealed container can be formed without deterioration of the sealing performance to the container main body for storing the contents.

  According to claim 1 of the present invention, the spherical particles contained in the content adhesion preventing layer have the effect of increasing the surface area of the content adhesion preventing layer by making the surface of the content adhesion preventing layer uneven. Hydrophobic oxide fine particles adhere to the periphery of the spherical particles and the surface of the thermal adhesive layer to improve the water repellent effect. In addition, the binder resin that provides adhesion to the thermal adhesive layer has a binder effect of adhering to spherical particles and hydrophobic oxide fine particles and adhering to the thermal adhesive layer. That is, a lid member having mechanical strength is provided.

  According to claim 2 of the present invention, in order to make the surface of the adhesion preventing layer uneven, by using a silicone resin having an average particle size in the range of 3 to 30 μm, the surface becomes uneven, and the surface area of the adhesion preventing layer is reduced. Can be bigger. Moreover, water repellency can be further improved by hydrophobizing the silicone resin.

  According to claim 3 of the present invention, by making the average particle diameter of the hydrophobic oxide fine particles having water repellency in the range of 5 to 20 nm, the hydrophobic oxide fine particles adhere around the spherical particles, Hydrophobic oxide fine particles can be disposed on any part of the unevenness by adhering to the surface of the thermal adhesive layer.

  According to claim 4 of the present invention, the binder resin adheres to the thermal adhesive layer and the spherical particles or hydrophobic oxide fine particles, thereby preventing the spherical particles and the hydrophobic oxide fine particles from peeling off.

  According to the fifth aspect of the present invention, by using particles having an average particle diameter of 1 to 5 μm for the binder resin, the surface for preventing the adhesion of contents can be further made uneven, and the surface area can be increased.

  According to claim 6 of the present invention, the water repellency can be further improved by setting the surface centerline average roughness Ra to Ra> 4 μm. In particular, the surface area of the content adhesion preventing layer can be increased, and the water repellent effect of the hydrophobic oxide fine particles can be further exhibited. The center line average roughness Ra can be measured using a center line average roughness measuring instrument.

  According to claim 7 of the present invention, hydrophobic silica having a trimethylsilyl group is particularly preferable in that adhesion prevention is obtained. Further, the water repellency can be improved.

  According to claim 8 of the present invention, by laminating an aluminum layer between the base material layer and the thermal adhesive layer, light shielding properties required for contents such as yogurt, jelly confectionery, pudding, oxygen, water vapor, etc. Gas barrier property can be improved. Further, when the lid material is opened, considering the necessity of the dead hold property that facilitates opening, it is preferable to laminate a metal foil. In particular, aluminum foil is preferable from the viewpoint of cost and productivity.

  According to claim 9 of the present invention, since the cover material of the present invention is formed with the content adhesion preventing layer, even if the cover material is opened, the content does not adhere to the inner surface of the cover material. . Moreover, a sealed container can be formed without impairing the sealing performance with the container body.

It is explanatory drawing which shows an example of the sealed container with which the cover material of this invention was attached. It is explanatory drawing which shows an example of the state which opened the cover material of the sealed container of FIG. It is sectional drawing which shows an example of the cover material of this invention. It is sectional drawing which shows an example of a content adhesion prevention layer. It is explanatory drawing which shows an example of the packaging bag using the content adhesion prevention layer. It is explanatory drawing which shows an example of the state which opened the conventional cover material.

  Hereinafter, embodiments for carrying out the present invention will be described.

  FIG. 1 is an explanatory view showing an example of a sealed container to which a lid material of the present invention is attached. The lid 1 is sealed to the flange 31 of the container body 30 to form a sealed container 40. The container body 30 has a cup shape in which an opening 32 and a flange 31 are formed. The container body 30 stores contents such as yogurt, for example.

  FIG. 2 is an explanatory diagram illustrating an example of a state in which the lid of the sealed container in FIG. 1 is opened. FIG. 2 shows an example of a state where a part of the lid 1 of the sealed container shown in FIG. 1 is opened. For example, even when the yogurt 11 is stored in the container body 30, the yogurt 11 is not attached to the inner surface of the lid 1.

  FIG. 3 is a cross-sectional view showing an example of the lid member of the present invention. The lid 1 is composed of a laminated body 20 in which a base material layer 2, an adhesive layer 3, an aluminum layer 4, an adhesive layer 5, a thermal adhesive layer 6, and a content adhesion preventing layer 7 are sequentially laminated.

  FIG. 4 is a cross-sectional view showing an example of the content adhesion preventing layer. The content adhesion preventing layer 7 contains spherical particles 8, hydrophobic oxide fine particles 9, and binder resin particles 10. The surface of the content adhesion preventing layer 7 is uneven. The irregularities are formed in a distributed state even when the spherical particles 8 having a large average particle diameter are dispersed in the contained substances and the spherical particles 8 are aggregated. Therefore, the surface is formed to be uneven. Further, in order to provide adhesion between the hydrophobic oxide fine particles 9, the spherical particles 8, and the thermal bonding layer 8, binder resin particles 10 are uniformly dispersed. Further, hydrophobic oxide fine particles 9 are arranged between the spherical particles 8 so as to cover almost the entire surface. The surface has irregularities of various sizes.

  The present invention will be described in more detail.

As the base material layer, for example, paper, synthetic paper, film or the like can be used. As the film, a single layer film such as polyester, polyethylene, polypropylene, polyamide, polycarbonate, polyvinyl chloride, cellulose acetate, cellophane, or a composite film thereof can be used. A composite material obtained by laminating the film on paper or the like can also be used.
The base material layer is usually appropriately printed to impart design properties.

  As the aluminum layer, for example, in the case of a lid for a container body that stores yogurt, pudding, etc., an aluminum foil having a thickness of about 5 to 50 μm is suitably used as a material that satisfies light shielding and light weight. Moreover, it can bond together using a common urethane type adhesive agent etc. for adhesion | attachment with a base material layer. Moreover, it is also possible to use the inorganic oxide vapor deposition film which vapor-deposited inorganic oxides, such as diatom oxide and aluminum oxide, on a film, without using aluminum foil.

  As a method for adhering the base material layer and the aluminum layer, they can be bonded through an adhesive layer. A wet lamination method, a dry lamination method, a non-solvent dry lamination method, and the like are possible. Moreover, when bonding using a hot-melt agent and polyethylene resin, the hot-melt lamination method, the extrusion lamination method, the sandwich lamination method using this extrusion lamination method, etc. are possible. For the adhesive layer, a urethane-based adhesive or the like can be used.

  The material for the heat bonding layer is not particularly limited as long as the heat bonding property with the container body is good. For example, polyolefins such as wax and ethylene-unsaturated ester copolymer, hot melt agent containing tackifier, ethylene-vinyl acetate copolymer resin, polyethylene resin, polypropylene resin, ethylene / acrylic acid copolymer resin, etc. A resin made of a resin, a polyester resin, a polyamide resin, or the like can be used. In particular, after confirming the sealing property and easy peel property with the container body, the material may be selected as appropriate.

  A urethane adhesive or the like can be used as an adhesive layer for bonding the aluminum layer and the thermal adhesive layer.

  As the spherical particles forming the content adhesion preventing layer, spherical particles containing at least one of an inorganic component and an organic component can be used. Examples of inorganic components include metals such as aluminum, copper, iron, titanium, silver, and calcium, or alloys or intermetallic compounds containing these metals, oxides such as silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, and iron oxide, and calcium phosphate. Inorganic acid salts or organic acid salts such as calcium stearate, ceramics such as glass, boron nitride, silicon carbide, and silicon nitride can be suitably used. Examples of organic components include acrylic resin, urethane resin, melamine resin, amino resin, epoxy resin, polyethylene resin, polystyrene resin, polypropylene resin, polyester resin, cellulose resin, vinyl chloride resin, silicone resin, polyvinyl alcohol, and ethylene-acetic acid. Resins such as a vinyl copolymer resin, an ethylene-vinyl alcohol copolymer resin, an ethylene-ethyl acrylate copolymer resin, a polyacrylonitrile resin, and a polyamide resin can be used.

  As the spherical particles in this embodiment, particles containing both an inorganic component and an organic component can be used in addition to particles made of an inorganic component or particles made of an organic component. Among these, spherical particles of silicone resin are particularly preferable.

  The average particle size of the spherical particles is preferably in the range of 3 to 30 μm. If the average particle size is less than 3 μm, it is insufficient in terms of forming irregularities on the surface of the above-mentioned content adhesion preventing layer. Variations in content adhesion prevention. On the other hand, when the average particle diameter exceeds 30 μm, there are problems in terms of dropping off of spherical particles, dispersibility, and the like.

The hydrophobic oxide fine particles forming the content adhesion preventing layer are hydrophobic silica having an average particle diameter of 5 to 20 nm. By setting the average particle size in the range of 5 to 20 nm, the hydrophobic oxide fine particles are uniformly dispersed and are arranged on the surface of the spherical particles or the heat-adhesive resin layer, so that excellent anti-adhesion properties can be obtained. it can. As the hydrophobic oxide fine particles, at least one kind of oxide such as silica, alumina, titania and the like can be used. For example, as silica, a hydrophobic silica having a methyl group, a hydrophobic silica having a trimethylsilyl group, a hydrophobic silica in dimethyl silicone oil, a hydrophobic silica in octylsilane, and the like can be used. As the alumina, hydrophobic alumina in dimethyl silicone oil can be used. As titania, hydrophobic titania with octylsilane can be used. In particular, hydrophobic silica having a trimethylsilyl group is preferable in that superior adhesion preventing properties can be obtained.

  If the average particle diameter of the hydrophobic oxide fine particles is less than 5 nm, it is mixed in the binder resin and unevenly distributed on the surface, so that the content adhesion preventing property varies. If the average particle diameter exceeds 20 nm, the hydrophobic oxide fine particles may fall off.

  As the binder resin for forming the content adhesion preventing layer, an excellent binder effect can be obtained by using any one of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, acrylic, styrene / butadiene rubber, or a mixture thereof. Can do. Moreover, the shape of this binder resin has a preferable spherical particle. Part of the spherical particles is dissolved to exhibit a binder effect, and the remaining spherical particles are allowed to contribute to the formation of irregularities on the surface of the content adhesion layer. The average particle diameter is particularly preferably in the range of 1 to 5 μm. When the binder resin particles are in the range of 1 to 5 μm in average particle size, the surface area of the thermal bonding layer can be increased, and a further adhesion preventing effect can be exhibited. When the average particle size is less than 1 μm, the binder effect is reduced. If the average particle size exceeds 5 μm, the cohesive force of the content adhesion preventing layer may be reduced. In particular, a polyethylene resin or an ethylene-vinyl acetate copolymer resin having an average particle diameter of 1 to 3 μm is preferable.

  In the method of forming the content adhesion preventing layer, first, spherical particles, hydrophobic oxide fine particles, and binder resin particles are dispersed in a solvent to prepare a coating solution. At this time, it is preferable to dissolve and disperse a part of the particles of the binder resin. By dissolving it, the binder effect is increased. As the solvent to be used, for example, an organic solvent such as ethanol, isopropyl alcohol, cyclohexane, toluene, acetone, propylene glycol, hexylene glycol, butyl diglycol, normal pentane, normal hexane, and hexyl alcohol can be used as appropriate. It is desirable to use ethanol from the viewpoints of environment, hygiene, and content adhesion prevention. Moreover, a dispersing agent, a coloring agent, an anti-settling agent, a viscosity adjusting agent, etc. can be used together in the coating solution as long as the effects of the present invention are not impaired.

  It coat | covers with an applicator using said coating liquid, and forms a content adhesion prevention layer. On the surface of the formed content adhesion preventing layer, spherical particles are uniformly dispersed and one or two particles are arranged. A primary aggregate is formed. By these spherical particles, a surface having irregularities with an average roughness Ra of Ra> 4 μm is formed. In addition, the binder resin particles for adhering the hydrophobic oxide fine particles and the spherical particles to the thermal adhesive layer are uniformly dispersed, and the hydrophobic oxide fine particles are arranged so as to cover almost the entire surface between the spherical particles and the spherical particles. Has been. A surface with irregularities of various sizes can be obtained. This unevenness increases the surface area of the surface and can further improve the water repellent effect.

  As a coating machine for applying the coating solution, known methods such as roll coating, gravure coating, bar coating, kiss reverse coating, die coating, doctor blade coating, brush coating, dip coating, spray coating, and spin coating can be used. The thickness of the content adhesion preventing layer is not particularly limited. What is necessary is just to determine suitably sealability, content adhesion prevention property, and easy peel property. The content adhesion preventing layer contains spherical particles, hydrophobic oxide fine particles, and binder resin particles, and therefore has good adhesion to the thermal adhesive layer and also has mechanical strength.

  When the surface of the formed content adhesion preventing layer is formed such that the center line average roughness Ra of the surface is Ra> 4 μm, the surface area becomes large and the content adhesion preventing property is further improved. Further, the content adhesion preventing layer contains spherical particles and hydrophobic oxide fine particles, whereby the easy peel property of the cover material can be added.

  The lid member is thermally bonded to the flange of the container body to form a sealed container. The lid material is also required to have an appropriate easy peel property. The lid | cover material of this invention is a lid | cover material which has sealing performance, the content adhesion prevention property, and easy peel property.

  The sealed container using the lid material of the present invention can be used for cup containers such as yogurt, pudding, jelly confectionery, tray containers and the like. Further, if the content adhesion preventing layer is formed on the inner surfaces of various containers, the content can be taken out without waste when taken out.

  In the present invention, the average particle diameter can be measured with a scanning electron microscope (FE-SEM). When the resolution of the scanning electron microscope is low, other electrons such as a transmission electron microscope are used. It is also possible to use a microscope together. Specifically, when the particle shape is spherical, the diameter is selected. When the particle shape is non-spherical, the average value of the longest diameter and the shortest diameter is regarded as the diameter, and arbitrarily selected by observation with a scanning electron microscope or the like 20 The average diameter of the individual particles was defined as the average particle diameter.

  Examples of the present invention will be described in detail below.

  A polyester film 12 μm and an aluminum foil 15 μm were dry laminated using a polyurethane adhesive to form a base material layer. The aluminum foil surface of the base material layer was anchor-coated using a polyurethane-based adhesive, and a low-density polyethylene resin as a heat-bonding layer was extruded to a thickness of 20 μm using an extruder on the anchor-coated surface and laminated.

  Next, a coating solution for forming the content adhesion preventing layer was formed according to the following formulation. Dispersion A prepared by dispersing an ethylene-vinyl acetate copolymer resin having an average particle diameter of 2 μm as a binder resin in water / ethanol (weight ratio 1/1) to a solid content of 50% by weight was prepared. Next, as a spherical particle, a silicone resin having a methyl group and an average particle diameter of 11 μm was dispersed in ethanol to prepare a dispersion B in which the solid content was adjusted to 5% by weight. Next, as a hydrophobic oxide fine particle, a dispersion C was prepared in which hydrophobic silica having a trimethylsilyl group and an average particle diameter of 10 nm was adjusted to a solid content of 5% by weight in ethanol.

  Next, Dispersion A, Dispersion B, and Dispersion C were mixed at a weight ratio of 1/2/10 to prepare Dispersion D, which was diluted and mixed with ethanol so that the total solid content was 8% by weight. A coating solution was prepared.

Next, the dispersion D was applied to the surface of the thermal adhesive layer by gravure coating at 1, 5 g / m ² to form a laminate. The drying temperature during the gravure coating was 80 ° C. for 30 seconds. Next, the laminate was fitted to the flange of the container body, punched out, and a lid material was created.

  Next, a lid material was prepared in the same manner as in Example 1 except that a silicone resin having a methyl group and an average particle diameter of 5 μm was used as the spherical particles.

Next, a lid material was prepared in the same manner as in Example 1 except that a silicone resin having a methyl group and an average particle size of 30 μm was used as the spherical particles.

  Next, a lid was prepared in the same manner as in Example 1 except that hydrophobic silica having trimethylsilyl groups and having an average particle diameter of 5 nm was used as the hydrophobic oxide fine particles.

  Next, a lid was prepared in the same manner as in Example 1 except that hydrophobic silica having trimethylsilyl groups and having an average particle diameter of 20 nm was used as the hydrophobic oxide fine particles.

  A lid was prepared in the same manner as in Example 1 except that the binder resin was an ethylene-vinyl acetate copolymer resin having an average particle diameter of 1 μm as the binder resin.

  A lid was prepared in the same manner as in Example 1 except that the binder resin was an ethylene-vinyl acetate copolymer resin having an average particle size of 5 μm as the binder resin.

  Hereinafter, the comparative example of this invention is demonstrated in detail.

<Comparative Example 1>
Next, a lid material was prepared in the same manner as in Example 1 except that a silicone resin having a methyl group and an average particle diameter of 2 μm was used as the spherical particles.

<Comparative example 2>
Next, a lid material was prepared in the same manner as in Example 1 except that a silicone resin having a methyl group and an average particle size of 33 μm was used as the spherical particles.

<Comparative Example 3>
Next, a lid was prepared in the same manner as in Example 1 except that hydrophobic silica having a trimethylsilyl group and an average particle diameter of 3 nm was used as the hydrophobic oxide fine particles.

<Comparative example 4>
Next, a lid material was prepared in the same manner as in Example 1 except that hydrophobic silica having a trimethylsilyl group and an average particle diameter of 23 nm was used as the hydrophobic oxide fine particles.

<Comparative Example 5>
Next, the binder resin was omitted in Example 1, and a dispersion B in which a silicone resin having an average particle diameter of 11 μm having a methyl group was dispersed in ethanol as spherical particles and adjusted to a solid content of 5% by weight was prepared. Next, as a hydrophobic oxide fine particle, a dispersion C was prepared in which hydrophobic silica having a trimethylsilyl group and an average particle diameter of 10 nm was adjusted to a solid content of 5% by weight in ethanol. Next, Dispersion B and Dispersion C were mixed at a weight ratio of 1/5, and dispersion E was prepared by diluting and mixing with ethanol so that the total solid content was 8% by weight to prepare a coating solution. The following was performed in the same manner as in Example 1 to prepare a lid.

<Comparative Example 6>
Next, a cover material was prepared in the same manner as in Example 1 except that an ethylene-vinyl acetate copolymer resin having an average particle size of 0.5 μm was used as the binder resin.

<Comparative Example 7>
Next, a cover material was prepared in the same manner as in Example 1 except that an ethylene-vinyl acetate copolymer resin having an average particle size of 6 μm was used as the binder resin.

  The following items were evaluated for the cover materials of Examples 1 to 7 and Comparative Examples 1 to 7.

<Seal strength>
-The lid | cover material of Examples 1-2 and Comparative Examples 1-7 was sealed with the impulse sealer to the flange of the cup container made from polyethylene. The flange is 3 mm wide. Seal strength was measured with a tensile tester.

<Contact angle>
-Drops of water and yogurt were dropped on the surface of the contents adhesion preventing layer of the lid materials of Examples 1 to 7 and Comparative Examples 1 to 7, and the contact angles were measured. Contact angle is measured by contact measuring device (solid-liquid interface analyzer “Drop
The contact angle was measured using Master 300 (Kyowa Interface Science Co., Ltd.).

<Tumble angle>
-Drops of water and yogurt were dropped on the surface of the lids of the lids of Examples 1 to 7 and Comparative Examples 1 to 7, tilted on a horizontal flatbed, and the angle when the water and yogurt droplets fell down. It was measured. The sliding angle was measured visually.

<Adhesiveness>
The adhesion after water and yogurt droplets were dropped was evaluated. ○: Adherence, x: Adherence was visually evaluated.

<Adhesion>
Using the content adhesion prevention layer as a test surface, using a Gakushin type abrasion resistance tester (JIS K 5701-1), evaluation of adhesion is performed with 30 reciprocations, load 200 g, mating material: polyester film 12 μm. It was. The presence or absence of removal of the content adhesion preventing layer on the polyester film was visually confirmed. ○: No dropout, x: Dropout was evaluated.

  The evaluation results are shown in Table 1.

評価結果から、球状粒子の粒径の範囲により、内容物付着防止層の表面の凹凸が変わり、接触角ならびに転落角から、ヨーグルトの付着防止性、即ち撥水性が良好で付着防止効果が観られた。疎水性酸化物微粒子の粒径の範囲でも、同様な結果が観られた。バインダーの粒径の範囲でも、同様な結果が観られた。またバインダー樹脂が含有されないものは、密着性が弱く、内容物付着防止層の脱落が観られた。実施例１〜７の内容物付着防止層の表面の中心線平均粗さＲａを測定したところ、共にＲａ＞４μｍであった。また実施例１〜７の蓋材では、シール強度も大きな低下はなく密封性を有していた。中心線平均粗さＲａの測定は、中心線平均粗さ測定器を用いた。

From the evaluation results, the unevenness of the surface of the content adhesion preventing layer changes depending on the particle size range of the spherical particles, and from the contact angle and the falling angle, the yogurt adhesion preventing property, that is, the water repellency is good and the adhesion preventing effect is observed. It was. Similar results were observed in the range of the particle size of the hydrophobic oxide fine particles. Similar results were observed in the range of binder particle size. In the case where the binder resin was not contained, the adhesiveness was weak and the content adhesion preventing layer was dropped. When the centerline average roughness Ra of the surface of the content adhesion preventing layer of Examples 1 to 7 was measured, both were Ra> 4 μm. Moreover, in the lid | cover material of Examples 1-7, the sealing strength did not have a big fall and it had sealing performance. The center line average roughness Ra was measured using a center line average roughness measuring instrument.

  By defining the range of the particle size of the spherical particles contained in the content adhesion prevention layer, it is possible to impart appropriate irregularities to improve the content adhesion prevention, and further content adhesion by coating with hydrophobic oxide fine particles The preventive property can be improved. Moreover, the adhesiveness of the content adhesion preventing layer can be improved by the binder resin.

The content adhesion preventing layer of the present invention can be formed on the inner surface of various containers in addition to the lid material. For example, the container shape can be used for a packaging bag, for example, a self-supporting packaging bag, a tray, a cup, a bowl, a tube or the like as shown in FIG. As a material, it can be used for containers made of plastic material, paper, a composite material of plastic and paper, metal or the like. The contents can also be used for solid, semi-solid, liquid, viscous, gel-like materials.

DESCRIPTION OF SYMBOLS 1 Cover material of this invention 2 Base material layer 3 Adhesion layer 4 Aluminum layer 5 Adhesion layer 6 Thermal adhesion layer 7 Content adhesion prevention layer 8 Spherical particle 9 Hydrophobic oxide fine particle 10 Binder resin particle 11 Yogurt 20 Laminate 30 Container Main body 31 Flange 32 Opening 40 Sealed container 50 Deposit 60 Conventional lid 70 Self-supporting packaging bag

Claims (8)

A lid made of a laminate in which at least a base material layer, a thermal adhesive layer, and a content adhesion preventing layer are sequentially laminated,
The content adhesion preventing layer is composed of spherical particles, hydrophobic oxide fine particles, and a binder resin ,
The binder resin is composed of particles having an average particle size in the range of 1 to 5 μm, and the resin particles have spherical particles and hydrophobic oxide fine particles fixed on the surface while maintaining the particle shape. Characteristic lid material.   The lid material according to claim 1, wherein the spherical particles are a silicone resin having an average particle diameter of 3 to 30 μm.   The lid material according to claim 1 or 2, wherein the hydrophobic oxide fine particles are hydrophobic silica having an average particle diameter of 5 to 20 nm.   The binder resin is any one of polyethylene, polypropylene, polyester, ethylene-vinyl acetate copolymer, acrylic, styrene-butadiene rubber, or a mixture thereof. The lid material described.   The lid material according to any one of claims 1 to 4, wherein a center line average roughness Ra of the surface of the content adhesion preventing layer is Ra> 4 µm.   The lid material according to claim 3, wherein the hydrophobic silica has a trimethylsilyl group. The lid material according to any one of claims 1 to 6 , wherein an aluminum layer is laminated between the base material layer and the thermal adhesive layer. A sealed container, which is sealed using the lid material according to claim 1 .

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