JP5908701B2 - Contents adhesion prevention lid material and manufacturing method thereof - Google Patents

Description

  The present invention is mainly applied to heat-sealing lid materials applied to food packaging containers, and more specifically to cup-shaped containers for packaging yogurt, jelly, pudding, jam, milk portion, coffee beverages and the like. The present invention relates to a lid member having a content adhesion preventing property and a manufacturing method thereof.

  This type of heat-sealing lid is generally provided with a heat-sealing layer on the film surface of a base material layer comprising a laminate of paper and a metal vapor-deposited film, or from a lamination of a base film and an aluminum foil. A heat seal layer, that is, a heat seal layer, is provided on the aluminum foil surface side of the base material layer as necessary via an intermediate resin layer. Then, the lid is placed on the upper surface opening of a cup-shaped container body filled with an object to be packaged such as yogurt, and the peripheral part is heat-sealed on the upper edge flange part of the container body to form a sealed package. It is supposed to be.

  Therefore, in such a lid material, good heat-sealing property, sealing property and appropriate easy peelability for opening are required, and at the same time, the non-adhesiveness of the contents, that is, the back surface of the lid material on the inner surface side of the container It is desirable that the content can be prevented from adhering to the surface. If the contents adhere to the back of the lid, fingers, clothes, or the surrounding area may be soiled when opened. This is to cause a disadvantage such as hosting.

  In response to such a request, conventionally, a proposal as shown in the following Patent Document 1 (Japanese Patent No. 4348401) has been made as means for imparting or improving contents adhesion prevention performance.

  The known technique according to this prior proposal is to form a porous layer having a three-dimensional network structure with extremely fine hydrophobic oxide particles such as hydrophobic silica on the outer surface of the heat sealing layer. Although it can have an excellent effect in terms of the prevention effect, in terms of adhesion to the heat sealing layer of the porous layer responsible for the adhesion prevention effect, stable sealing strength over the entire circumference of the lid, and sealing strength There was a slight problem. That is, the anti-adhesion layer is formed as a porous layer of hydrophobic oxide fine particles by applying the hydrophobic oxide fine particles as a dispersion using a dispersion medium such as alcohol on the heat sealing layer and then drying. Therefore, it is structurally fragile in itself, and generally has a weak bonding force or adhesion to the adjacent heat sealing layer, and is likely to cause partial peeling or dropping off of the anti-adhesion layer. There is a possibility that foreign matter may be mixed, which is not only preferable for hygiene, but also the adhesion preventing effect may not be stable.

  In addition, since the adhesion preventing layer composed of a porous layer of hydrophobic inorganic fine particles becomes a contaminant in the heat seal portion, it is difficult to obtain a stable and uniform sealing adhesion strength and peeling resistance strength on the entire circumference, and a sealing strength. There is also a problem that the contents may inadvertently leak from a weak part of the product, or the contents may be scattered when trying to open the cover by strongly pulling the part with a strong seal strength. It was.

  Furthermore, even when sealing after filling containers such as yogurt, jelly, and pudding, the effect of preventing the adhesion of the contents is impaired due to the severe heat effect that the lid receives from the hot plate during standby or heat sealing. There is a fear that the content adhesion preventing effect is particularly remarkably lowered in the vicinity of the heat seal portion, that is, in the vicinity of the flange portion of the container as compared with other portions. For this reason, the process management at the time of manufacture of a lid | cover material and heat sealing is a little troublesome, and there existed a difficulty that handling was difficult.

  On the other hand, with respect to the problem of the stability of the adhesion and seal strength of the prior art disclosed in Patent Document 1 as described above, it is possible to further improve the non-adhesiveness while solving this problem. As a technique, the present inventors previously proposed the invention described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2011-184082).

  In this prior proposed technique, the adhesion preventing layer is composed of a mixed composition of hydrophobic inorganic fine particles and a thermoplastic resin binder, and the adhesive strength is increased by the binder and the heat sealing property of the heat sealing layer is supplemented. This ensures a stable heat-sealing property and sealing strength on the entire periphery of the container body of the lid material regardless of the presence of the conductive inorganic fine particle group.

  However, on the other hand, in the actual production of the lid material performed in accordance with the prior proposal technique, the preparation of the dispersion coating liquid by the mixed composition with the agitation essential for obtaining uniform diffusion of the inorganic fine particles, the uniform Each process such as coating and drying after coating requires fairly strict condition management, and there is a risk that even if a slight deviation from the process management conditions, the anti-adhesion performance desired for the anti-adhesion layer may not be obtained. It has turned out that there is.

Japanese Patent No. 4348401 JP 2011-184082 A

  The present invention is intended to further improve the above-mentioned problems, specifically, while maintaining stable and good heat seal performance, it is excellent in content adhesion prevention performance and also exhibits the adhesion prevention effect. An object of the present invention is to provide a new improvement technology that can improve the adhesion and stability of the content adhesion preventing effect by improving the adhesion between the heat-sealing layer of hydrophobic fine particles and the adhesion between the lid and the container. .

  Then, this invention presents the content adhesion prevention lid | cover material and its manufacturing method as described in following [1]-[8] as a concrete technical means for achieving said objective.

[1] In a lid having at least a base material layer and a heat sealing layer,
On the outer surface of the heat sealing layer, a particle coating layer for content adhesion prevention having a coating amount of 0.5 to 1.5 g / m ^{2 made} of hydrophobic dry silica particles is formed,
An impregnation adhesion reinforcing layer in which the molten component of the heat sealing layer enters at least a gap between the dry silica particles is formed on a part of the particle covering layer on the heat sealing layer side, A content adhesion preventing lid material, wherein an adhesion preventing layer having a residual particle amount of 0.3 to 1.2 g / m ^{2 made} of particles having exposed surfaces is formed on the outermost surface side.

  [2] The content adhesion preventing lid material according to [1], wherein the hydrophobic dry silica particles have an average primary particle size of 3 to 50 nm.

  [3] An adhesive resin component in which the heat sealing layer is composed of one or more of acid-modified polyolefin resin, ethylene-unsaturated ester copolymer, acrylic resin, polyester resin, and styrene resin; The content adhesion preventing lid material according to the above item [1] or [2], which comprises a resin composition containing at least one of wax and tackifier as an essential component.

  [4] The content adhesion preventing lid material according to [3], wherein the blending amount of the wax and / or tackifier of the resin composition is 1 to 70% by weight.

  [5] The content adhesion preventing lid material according to [3] or [4], wherein the wax of the resin composition has a melting point of 80 ° C. or higher.

[6] A coating liquid prepared by dispersing hydrophobic dry silica particles in an organic dispersion medium is applied to the outer surface of the heat sealing layer of the cover material having at least a base material layer and a heat sealing layer, and then dried. Forming a particle coating layer for preventing content adhesion of 0.5 to 1.5 g / m ² ;
And, by performing a heat treatment at a temperature higher than the melting start temperature (softening point) of the heat sealing layer component, a part of the particle coating layer on the heat sealing layer side is at least between the particles of the dry silica particles. Forming an impregnated adhesion strengthening layer in which the molten component of the heat sealing layer has entered into the gap of the particle, and the surface of the dry silica particles is not covered with the heat sealing layer component on the outermost surface side of the particle coating layer. A method for producing a content adhesion preventing lid material, wherein an adhesion preventing layer having an exposed residual particle amount of 0.3 to 1.2 g / m ² is left to be formed.

  [7] The method for producing a content adhesion preventing lid material according to [6], wherein the hydrophobic dry silica particles have an average primary particle diameter of 3 to 50 nm.

  [8] The method for manufacturing a content adhesion preventing lid material according to [6] or [7], wherein the heat treatment is performed under a heat treatment condition of a temperature of 85 to 220 ° C. and a time of 3 to 120 seconds.

In the configuration of the above item [1], the present invention provides a particle coating layer for preventing the adhesion of contents in a large number of coating layers of 0.5 to 1.5 g / m ^{2 made} of hydrophobic dry silica particles. An impregnated adhesion enhancing layer in which a heat sealing layer component enters a part of the particle coating layer into a space between the particles by, for example, performing an appropriate heat treatment thereon. As a result, the dry silica particles are constrained and fixed to each other by the components of the heat-sealing layer solidified by filling the voids between the particles, particularly the low viscosity and low molecular weight components, and that of the particle coating layer. It itself is firmly fixed to the heat sealing layer by the anchor effect. In addition, an adhesion preventing layer having a residual particle amount of 0.3 to 1.2 g / m ² is formed on the outer surface side of the particle coating layer by the hydrophobic dry silica particles with the particle surface exposed. In addition to the inherently good water repellency of silica particles, combined with the fine concavo-convex structure formed on the outer surface of the particle coating layer, it exhibits excellent adhesion prevention performance. Therefore, adhesion to the heat sealing layer can be improved, and unintentional particles can be prevented from falling off or partially peeled off, thereby ensuring a stable content adhesion preventing effect over a long period of time. In addition, the heat-sealing layer component that has entered the gaps between the dry silica particles acts to supplement the heat-sealing properties of the heat-sealing layer, and it is good and stable against the container body of the lid regardless of the presence of the dry silica particle coating layer. Heat sealability and adhesion can be achieved.

  Further, by using hydrophobic dry silica particles having an average particle size as described in the above item [2], the above-mentioned effects can be reliably achieved with a relatively inexpensive material that is easily available from the market. .

  Further, as described in the above item [3], the heat sealing layer is made of a resin composition containing a specific type of adhesive resin component and at least one of wax and tackifier as essential components. The above-mentioned effects can be achieved while ensuring good heat-sealing properties, sealing properties, and easy peelability at the time of opening.

  Further, as described in the items [4] and [5], the resin composition contains a predetermined amount of at least one of a wax and a tackifier, and preferably the melting point of the wax is 80 ° C. By selecting the above, in addition to the effect of the item [3], the thermal stability or heat resistance of the particle coating layer for preventing adhesion can be further improved, and the item [1]. Thus, when the impregnation adhesion reinforcing layer is formed, the effect can be achieved more reliably.

  Further, according to the production method described in the above item [6], not only can the lid having the effect of the item [1] be obtained, but in particular, hydrophobic dry silica particles are dispersed in an organic dispersion medium. Since the particle coating layer is formed by applying and drying the dispersion prepared in this manner, a uniform particle coating layer can be formed relatively easily, and as the dispersion medium is volatilized in the drying process, fine dry silica particles are formed. Combined with the fact that the particle coating layer is formed into a porous aggregated layer containing fine and irregular voids due to its strong cohesive force, it is heat sealed at least by a heat treatment performed after application of the dispersion. When the layer melts, its low viscosity and low molecular weight components easily enter the voids between the particles, and by filling the voids, an adhesion strengthening layer with sufficiently improved adhesion with the heat sealing layer is easily formed. This Can.

  Further, by using hydrophobic dry silica particles having an average particle size as described in the above item [7], a lid material having the effect of the item [2] can be obtained.

  Furthermore, by applying the heat treatment under the conditions described in the above item [8], adhesion prevention is possible in any case under the selective use of various materials for the heat sealing layer exhibiting good heat sealing characteristics. It is possible to form the impregnation adhesion reinforcing layer while reliably remaining the layer.

FIG. 1 is a cross-sectional view showing an outline of an example of a laminated structure of a content adhesion preventing lid material according to the present invention. FIG. 2 is a schematic cross-sectional view schematically showing the structure of the particle coating layer for preventing adhesion according to the present invention, which is shown upside down with respect to FIG.

  FIG. 1 shows an example of a laminated structure of a content adhesion preventing lid according to the present invention.

  The lid material is, as an example of a lid material suitable for a container for yogurt packaging, generally coated paper (2) having a printing (7) surface protected with a coating agent (2a) and a metal vapor deposition film (3). A laminated body bonded with an adhesive is used as a base material (1), and a heat sealing layer (5) is provided on the outer surface of the base material (1) on the metal vapor deposition film (3) side via an anchor coat (4). It is what was done. This laminated structure is the same as that of a conventionally known lid material, and the laminated body including the base material (1) and the heat sealing layer (5) is referred to as a “lid material body” herein.

  Said metal vapor deposition film (3) provides gas barrier property, light-shielding property, etc., and an aluminum vapor deposition polyester film is used in many cases. Particularly in the case of a lid for a yogurt container, an aluminum vapor-deposited polyester film having a thickness of about 12 to 16 μm is suitably used as a light-shielding property and light weight. In addition, a general adhesive is used for laminating and bonding with the coated paper (2).

  In the case of a lid material using a hot melt agent for the heat sealing layer (5), the lid body is composed of a base material layer formed by laminating a lid material film layer and a metal foil layer, and the base material layer. A heat sealing layer is provided on the outer surface of the metal foil side through an intermediate layer as necessary.

  By the way, the content adhesion preventing lid material according to the present invention further has a particle coating layer (6) for preventing adhesion on the outer surface of the heat sealing layer (5) of the lid body.

  The material of the heat sealing layer (5) is not particularly limited as long as it has good adhesion to the container side. For example, a lacquer type heat sealant, a hot melt agent, or a known sealant film can be used. Preferably, an adhesive resin component composed of one or more of acid-modified polyolefin resin, ethylene-unsaturated ester copolymer, acrylic resin, polyester resin, and styrene resin, and wax and tackifier What consists of a resin composition which contains at least any one of an agent as an essential component can be used. In this case, the wax and tackifier in the resin composition are set to at least one of them or the total amount of 1 to 70% by weight, and their melting point or softening point is 80 ° C. or higher. It is desirable to adopt what is. In particular, a wax having a melting point of 80 ° C. or higher should be adopted. When the blending amount is less than 1% by weight, the effect of adding them cannot be fully enjoyed. When the content exceeds 70% by weight, the particle coating is caused by heat treatment or heat influence during heat sealing. There exists a possibility that the adhesion prevention performance of a layer (6) may be impaired. Further, if the melting point or softening point thereof is less than 80 ° C., the water repellency of the particle coating layer (6) and thus the thermal stability of the adhesion preventing effect may be impaired. That is, due to the heat effect received during heat sealing or the like, the low melting point component of the heat sealing layer (5) is melted early and excessively to express high fluidity, covering the surface of the silica particles through the gaps between the silica particles. The exposed area is reduced, and as a result, the adhesion preventing effect may be impaired. Preferably, the blending amount is set in a range of 10 to 60% by weight, and a melting point or a softening point of 90 to 120 ° C. is preferably selected and used.

  The particle covering layer (6) for preventing adhesion, which is the main feature of the present invention, is composed of hydrophobic dry silica particles (S).

  The dry silica particles (S) are produced as an aggregate of very fine primary particles by a flame method or the like, and those having an average primary particle size of 3 to 50 nm can be suitably used. Ultrafine particles having an average particle size of less than 3 nm are difficult to obtain from the market and are disadvantageous in terms of cost. On the other hand, coarse dry silica having an average primary particle size of more than 50 nm is poor in improving the adhesion of the particle coating layer (6). Particularly preferred are dry silica particles having an average primary particle size of 5 to 20 nm.

  The particle coating layer (6) is formed by uniformly dispersing a predetermined amount of hydrophobic dry silica particles (S) in a liquid dispersion medium to prepare a dispersion, which is used as a heat sealing layer (5) for the lid body. It can carry out suitably by applying to the outer surface of the substrate and drying.

  The dispersion is prepared by dispersing a predetermined amount of the above-described dry silica particles using an organic liquid dispersion medium to obtain a colloidal solution having a predetermined concentration. The dispersion medium is particularly an organic dispersion medium having a polar group. Is preferred. Of these, the use of alcohols is preferred, and the use of methanol or ethanol is particularly preferred from the standpoints of cost, safety, water repellency, and the like.

  Any known method can be employed for coating the dispersion. For example, a gravure coating method, spraying, a bar coating method, etc. can be arbitrarily adopted.

The coating amount of the dispersion liquid may be set according to the desired thickness of the adhesion preventing layer, but should be set in the range of 0.5 to 1.5 g / m ^{2 by} weight after drying, preferably 0. .6 to 1.3 g / m ² should be set.

When the coating amount is less than 0.5 g / m ² , almost all of the particle coating layer (6) in the thickness direction is filled with the heat sealing layer component by the heat treatment described later, and the adhesion preventing layer (6b) in which the particle surface is exposed. ) It becomes difficult to form the remaining part. On the other hand, when it is applied excessively exceeding 1.5 g / m ² , the adhesion of the particle coating layer (6) becomes poor.

  It may be naturally dried as well as dried after application, but is preferably dried by heating in order to enhance productivity and adhesion to the heat sealing layer. As drying conditions in that case, it is desirable to set the temperature in the range of 80 to 140 ° C. and the time of 5 to 30 seconds.

  In the particle coating layer (6) formed by the coating, that is, the coating and drying process as described above, the hydrophobic dry silica particles (S) constituting the particle coating layer are randomly fused and primary bonded at the production stage. Even in the case of primary agglomerate particles, the particle size is very small particles of about 300 nm or less. Therefore, as the dispersion medium is volatilized and removed in the drying step after applying the particle dispersion, The silica particles (S) are formed as a porous aggregated layer on the surface of the heat sealing layer (5) in combination with the strong cohesive force of the silica particles (S). As a result, the particle coating layer (6) itself has excellent surface water repellency, and exhibits relatively good adhesion because it contacts the heat sealing layer (5) at many points of contact. Still, satisfactory satisfaction cannot be obtained in terms of adhesion.

  Therefore, in the present invention, after the formation of the particle coating layer (6) as described above, the heat sealing of the particle coating layer (6) is performed as shown in a schematic diagram of FIG. On part of the layer (5) side, an impregnated adhesion reinforcing layer (6a) in which the molten component of the heat sealing layer has entered the gap between the particles of the dry silica particles (S) is formed. On the outer surface side, the adhesion preventing layer (6a) that remains with the surface of the hydrophobic dry silica particles (A) exposed is left to be formed.

  When the laminate is heated at a temperature equal to or higher than the melting start temperature of the heat sealing layer (5) after the formation of the particle coating layer (6), the low melting point component, low viscosity component, low The molecular weight component is fluidized and enters the voids of the aggregated layer of dry silica particles (S) having a fine porous structure, and is cooled and solidified to form the impregnated adhesion reinforcing layer (6a). Accordingly, the particle coating layer (6) is integrally bonded to the heat sealing layer (5) by the impregnated adhesion reinforcing layer (6a), thereby strengthening the adhesion.

  However, the formation of the adhesion strengthening layer (6a) by the heat treatment described above is such that at least the surface of the hydrophobic dry silica particles (S) is not covered with the molten component on the outermost surface portion of the particle coating layer (6). It must be performed under conditions that allow the exposed portion of the anti-adhesion layer (6b) to remain.

Moreover, the composition of the heat sealing layer (5) and the particle coating layer (6) are adjusted so that the amount of residual particles forming the adhesion preventing layer (6b) is in the range of 0.3 to 1.2 g / m ² . The heat treatment conditions are determined in consideration of the correlation with the coating amount and the like. When the residual particle amount of the adhesion preventing layer (6b) is less than 0.3 g / m ² , the desired good adhesion preventing performance cannot be expressed. On the contrary, when it exceeds 1.2 g / m ² , the adhesion of the particle coating layer (6) is deteriorated, and the possibility of the silica particles falling off and peeling off increases. A preferable range of the residual particle amount is approximately 0.3 to 1.0 g / m ² .

  Here, the measurement of the amount of the remaining particles forming the adhesion preventing layer (6b) is performed by wiping the surface of the sample covering layer cut out to a predetermined area with absorbent cotton soaked with alcohol or the like. It can be determined from the difference in weight before and after wiping.

  The heat treatment for forming the adhesion preventing layer (6b) remaining is at least higher than the melting start temperature of the heat sealing layer (5) in consideration of the relationship with the material used for the heat sealing layer (5). It is necessary to carry out at a temperature, preferably 50 ° C. or higher. Although this heating temperature correlates with the heating time, generally preferable heat treatment conditions are a temperature of 85 to 220 ° C. and a time of 3 to 120 seconds, and particularly preferably a temperature of 100 to 180 ° C. and a time of 5 to 60 seconds. is there.

  In addition, said heat processing performed for formation of an impregnation adhesion reinforcement | strengthening layer (6a) is performed on the most preferable conditions by performing as a separate separate process after application | coating of the dispersion liquid of a dry-type silica particle (S), and drying. Although process management is easy, in order to simplify a work process, it is good also as what performs the drying process after application | coating, and a heat processing process simultaneously or continuously.

  Next, in order to confirm the effect of the present invention, various examples thereof are shown in comparison with comparative examples or control examples.

(Preparation of lid body)
The lid main body uses a lacquer type heat sealing agent for its heat sealing layer (sample No. 1-8, 12-14, 16, 17) and a hot melt agent (sample No. 9-11). , 15) were prepared as shown in a and b below.

a, Lid using a lacquer type heat sealant Coated paper (55 g / m ² ) and a 16 μm thick aluminum vapor-deposited polyethylene terephthalate film, which were laminated with a polyurethane-based dry laminate adhesive to form a base material layer .

Next, after applying an anchor coating agent to the aluminum vapor-deposited polyethylene terephthalate film of the base material layer, it is further subjected to a gravure coating method thereon, and various compounding compositions as shown in Table 1 as being suitable for a lid for a polystyrene container. In each case, a heat sealing layer having a coating amount of 5 g / m ² was formed using the lacquer type heat sealing agent. The base material layer / anchor coating agent / heat sealing layer laminate thus obtained was used as a lid body.

b, Lid using a hot melt agent A polyethylene terephthalate film having a thickness of 12 μm was used as a substrate film, and an aluminum foil having a thickness of 30 μm was bonded to one surface thereof with a polyurethane dry laminate adhesive to form a substrate layer.

Next, an anchor coating agent is applied to the surface of the base material layer on the aluminum foil side, and a polyethylene resin is extruded and coated so as to have a thickness of 20 μm to form an intermediate resin layer. A heat sealing layer having an application amount of 18 g / m ² was formed using a hot melt agent having a composition as shown in Table 1. The base material layer / intermediate resin layer / heat sealing layer laminate thus obtained was used as a lid body.

  The following materials were used as the constituent materials of the heat sealing layers a and b.

Heat sealing layer constituent material Acid-modified polyolefin resin Acid-modified PO: Acid-modified polypropylene resin (grafted with maleic anhydride graft)
Denaturation rate 1.0%)
Ethylene-unsaturated ester copolymer EVA: ethylene-vinyl acetate copolymer (190 ° C. MFR 20 g / 10 min, vinegar
(20% vinyl acid content)
Wax (WX)
WX (I): Polyethylene wax having a melting point of 125 ° C. WX (II): Paraffin wax having a melting point of 75 ° C. Tackifier (TF)
TF (I): Petroleum-based hydrogenated resin Melting point 115 ° C

(Formation of anti-adhesion particle coating layer)
The following hydrophobic dry silica particles were prepared as materials for the adhesion preventing particle coating layer.

Hydrophobic dry silica particles (S)
S (I): Hydrophobic dry silica, primary particle average particle size 7 nm,
Specific surface area by BET method 220m ² / g
S (II): Hydrophobic dry silica Primary particle average particle size 12 nm
Specific surface area by BET method 300m ² / g

  The hydrophobic dry silica particles S (I) and S (II) were each uniformly dispersed in ethanol to prepare various dispersions.

And these dispersion liquids were apply | coated to the outer surface of the said heat sealing layer (5) of a lid | cover material main body (1) by the gravure coating method, and forcedly dried and the particle | grain coating layer (6) was formed. Here, the application amount of silica particles was variously set in the range of 0.6 to 1.3 g / m ² as shown in Table 1 in terms of weight after drying. Moreover, all forced drying was performed on the drying conditions of temperature 100 degreeC x time 15 seconds.

(Heat treatment)
After forming the particle coating layer (6) as described above, the obtained laminate was subjected to heat treatment (excluding sample No. 16). The heat treatment conditions depended on the temperature and time as shown in Table 1.

  After heat treatment, it was confirmed by observation with an electron microscope that an impregnated adhesion reinforcing layer (6a) in which the heat sealing layer component entered the particle coating layer (6) on the heat sealing layer (5) side was formed for each sample. The amount of particles in the adhesion preventing layer portion remaining thereon, that is, the residual particle group that is recognized that the surface of the dry silica particles is exposed as it is without being covered with the heat sealing layer component. The amount of particles in the anti-adhesion layer (6b) was examined and listed in Table 1 as the amount of particles in the “residual anti-adhesion layer”.

  Here, the measurement of the particle amount of the residual adhesion preventing layer (6a) was performed by the method described above.

(Evaluation test)
(1) Anti-adhesion performance Each sample No. Aloe yogurt (Trademark “Morinaga Aloe Yogurt” manufactured by Morinaga Milk Industry Co., Ltd.) is dropped as a 0.5 cc droplet onto the back of the lid material 1 to 17, ie, the outer surface of the adhesion preventing layer, and the sample is slowly tilted. When the above-mentioned droplet was measured, the “inclination angle when it started to roll” was measured and evaluated according to the following criteria.

◎ ・ ・ ・ 15 degrees or less ○ ・ ・ ・ 16 degrees or more and 30 degrees or less × ・ ・ ・ 31 degrees or more

(2) Heat seal strength Sample No. Cut out the lid material of 1 to 17 into a width of 15 mm, and for sample Nos. 1 to 8, 12 to 14, 16, and 17, the container body (polystyrene container) under sealing conditions of 180 ° C. × 0.2 MPa × 1.0 sec Heat-sealed into a 15 mm wide strip cut out from Sample Nos. 9 to 11 and 15 were heat-sealed into strips having a width of 15 mm cut out from the container body (paper / polyethylene container) under sealing conditions of 150 ° C. × 0.2 MPa × 1.0 sec. Next, the lid member was pulled in the direction of 180 ° at a speed of 100 mm / min, and the maximum load at the time of peeling was defined as the heat seal strength.

And the heat seal strength in the lid material as it is without the particle coating layer (
The reduction rate or increase rate of the heat seal strength was judged and evaluated based on the following criteria, with the peel strength and sealability of the lid material as the reference value.

◎ ・ ・ ・ Reduced strength or increase less than 10% ○ ・ ・ ・ Reduced strength or increase 10% to less than 20% × ・ ・ ・ Reduced strength or increased 20% or more

(3) Adhesion Sample No. A weight (500 g) in which a black cloth is wrapped around the surface of the adhesion preventing layer of each of the lid materials 1 to 17
) Was placed vertically, rubbed slowly for 200 mm in length, and the presence or absence of silica particles transferred and adhered to the surface of the cloth was visually inspected.

  And it evaluated on the following evaluation criteria by the transfer adhesion amount (peeling amount) of the silica particle on a black cloth.

◎ ・ ・ ・ Almost no adhesion ○ ・ ・ ・ Slight adhesion that is considered acceptable range × ・ ・ ・ Clearly much adhesion

  Table 2 shows the results of the evaluation tests (1) to (3).

  As shown in the test results of “Adhesion prevention performance” in Table 2, in the contents adhesion prevention lid material according to the present invention, the yogurt droplet starts rolling and moving only by slightly tilting the sample. This is because the contents on the back surface of the lid material are sealed against the contents even after the lid material is heat-sealed in a container filled with contents containing viscous liquid components such as yogurt, pudding, and jelly. It shows that it has an excellent anti-adhesion effect. Moreover, as shown in the results of the “sealability” test, the presence of the anti-adhesion layer does not significantly impair the heat sealability (seal strength), and provides the above anti-adhesion performance while maintaining an appropriate sealing performance. sell. In addition, as seen in the results of the “adhesion” test, the adhesion of the particle-preventing particle coating layer is good, and there is no risk of unintentional separation or dropping, partial peeling, etc. The prevention performance can be maintained stably, and there is no possibility of foreign matter entering the container.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Coated paper 3 ... Metal vapor deposition film 4 ... Anchor coating layer 5 ... Heat sealing layer 6 ... Particle coating layer 6a for adhesion prevention .... Adhesion reinforcement layer 6b ..Anti-adhesion layer S ... hydrophobic dry silica particles

Claims (3)

It has at least a base material layer and a heat sealing layer, and the heat sealing layer is one of acid-modified polyolefin resin, ethylene-unsaturated ester copolymer, acrylic resin, polyester resin, and styrene resin. Or a resin composition containing two or more types of adhesive resin components and at least one of wax and tackifier as essential components, and the blending amount of the wax and / or tackifier of the resin composition is 1 to 70% by weight, and a melting point or a softening point of the wax and the tackifier is 80 ° C. or higher,
On the outer surface of the heat sealing layer of the lid body, a dispersion prepared by dispersing hydrophobic dry silica particles in an organic dispersion medium is applied and dried to a coating amount of 0.5 to 1.5 g / m. ² A particle coating layer for preventing the adhesion of the contents of
Next, by performing a heat treatment at a temperature higher than the melting start temperature (softening point) of the heat sealing layer component, a part of the particle coating layer on the heat sealing layer side is at least between the particles of the dry silica particles. Forming an impregnated adhesion strengthening layer in which the molten component of the heat sealing layer has entered into the gap of the particle, and the surface of the dry silica particles is not covered with the heat sealing layer component on the outermost surface side of the particle coating layer. Exposed residual particle amount 0.3-1.2 g / m ² A method for producing a content adhesion prevention lid material, wherein the adhesion prevention layer is left to be formed. The method for producing a content adhesion preventing lid according to claim 1, wherein the hydrophobic dry silica particles have an average primary particle size of 3 to 50 nm. The said heat processing is a manufacturing method of the content adhesion prevention lid | cover material of Claim 1 or 2 performed on the heat processing conditions of temperature 85-220 degreeC and time 3 to 120 sec.

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