JP2014015236A - Cup container made of synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the contents from adhering on an inner surface of a cup container with an industrially simple process by utilizing an effect of suppressing the adherence of the contents due to the water repellency of hydrophobic oxide fine particles, and to provide a cup container made of a synthetic resin having excellent usability.SOLUTION: In a cup container made of a synthetic resin, a hydrophobic film is bonded to a predetermined area of an inner surface of a cup body via one surface side of a base material film by insert molding using a hydrophobic film, on which a hydrophobic layer is formed by adhering hydrophobic oxide particles on the other surface of the base material film, as an insert material.

Description

The present invention relates to a synthetic resin cup container in which adhesion of contents is suppressed.

Synthetic resin cup containers are widely used as packaging materials for sol or gel foods such as yogurt, pudding, and jelly, but in this type of application, the contents easily adhere to the inner surface of the container. It is difficult to eat cleanly without waste.
In particular, loose liquids such as yogurt cannot be removed cleanly even with a spoon, and consumers are dissatisfied. Since it cannot be washed, it may be difficult to dispose of it separately.

In this regard, Patent Document 1 describes an invention in which hydrophobic oxide fine particles are attached to a predetermined portion of a wall surface of a container to impart water repellency, and the amount of yogurt or the like is effectively suppressed. Examples are described that can be applied, i.e. non-adhesive. As the hydrophobic oxide fine particles, those having no influence on the human body such as hydrophobic silica can be selected, and can be used with confidence in the food field.

JP 2010-254377

The present invention utilizes the effect of suppressing the adhesion of the contents due to the water repellency of the above-mentioned hydrophobic oxide fine particles, and effectively adheres the contents to the inner surface of the cup container industrially in a simpler process. It is an object of the present invention to provide a synthetic resin cup container that is excellent in usability.

The main configuration of the present invention related to the means for solving the above technical problem is:
In a synthetic resin cup container,
By insert molding using a water-repellent film in which hydrophobic oxide fine particles are attached to one surface of a base film to form a water-repellent layer,
The water repellent film is adhered to a predetermined region of the inner surface of the cup body through the other surface side of the base film.

  According to the above configuration, the water-repellent film is placed inside the cup body in consideration of the contents to be stored in the cup container and the usage of the product storing the contents by insert molding using the water-repellent film as an insert material. By adhering to a predetermined region on the surface, the content of the inner surface of the cup body in the region is formed by a water-repellent layer made of hydrophobic oxide fine particles (hereinafter sometimes simply referred to as fine particles). Can be effectively suppressed.

  In addition, since a water-repellent film prepared in advance may be insert-molded as an insert material, a post-process for applying and drying a coating liquid in which hydrophobic oxide fine particles are dispersed for each molded cup container is unnecessary. Yes, with high productivity, can impart water repellency, that is, non-adhesiveness of the content liquid

  In insert molding, the water-repellent film, which is an insert material, is pressed against the cavity surface of the mold by a molten resin at a high temperature and under pressure, so that a part of the base film is softened or melted. The material film improves the adhesion to the cup body, effectively prevents the water-repellent film from peeling off during use of the product, and the non-adhesive effect of the contents can be maintained stably for a longer period of time. It becomes.

  Another configuration of the present invention is that, in the main configuration described above, a water repellent film is bonded to the inner peripheral surface of the side peripheral wall of the body portion of the cup body.

  Still another configuration of the present invention is that the water repellent film is adhered to the inner surface of the bottom wall of the bottom of the cup body in the main configuration described above.

In the inner surface of the cup body, the region to which the water-repellent film is adhered can be appropriately selected in consideration of the attachment mode of the content, the usage mode of the product containing the content, the productivity of insert molding, etc.
It can be bonded over the entire inner surface, or it can be bonded in a limited manner to the inner peripheral surface of the side peripheral wall of the trunk portion or the inner surface of the bottom wall of the bottom portion as described above.
Furthermore, it is also possible to adhere to a limited region of the inner peripheral surface of the side peripheral wall of the trunk portion.

  Still another configuration of the present invention is that, in the main configuration described above, the hydrophobic oxide fine particles are made of hydrophobic silica, and further, the surface is made of hydrophobic silica having a trimethylsilyl group.

The hydrophobic oxide fine particles are not particularly limited as long as they have hydrophobicity, and may be those hydrophobized by surface treatment. For example, fine particles in which hydrophilic oxide fine particles are subjected to a surface treatment with a silane coupling agent or the like to make the surface state hydrophobic can also be used. The type of oxide is not limited as long as it has hydrophobicity. For example, at least one of silica (silicon dioxide), alumina, titania and the like can be used. These may be known or commercially available. For example, as silica, product names “AEROSIL R972”, “AEROSIL R972V”, “AEROSIL R972CF”, “AEROSIL R974”, “AEROSIL RX200”, “AEROSIL RX300”, “AEROSIL NX90G”, “AEROSIL RY200” (and above, Nippon Aerosil Co., Ltd.), “AEROSIL R202”, “AEROSIL R805”, “AEROSIL R812”, “AEROSIL R812S”, “AEROSIL R8200” (above, manufactured by Evonik Degussa). Examples of titania include “AEROXIDE TiO2 T805” (manufactured by Evonik Degussa). As alumina, the product name “AEROXIDE”
Alu C ”(manufactured by Evonik Degussa) or the like is treated with a silane coupling agent, and fine particles having a hydrophobic particle surface can be exemplified.

  Among the above-described hydrophobic oxide fine particles, hydrophobic silica fine particles having a trimethylsilyl group on the surface are preferable in that hydrophobic silica fine particles can be suitably used and more excellent non-adhesiveness can be obtained. As a commercially available product corresponding to this, for example, “AEROSIL RX200”, “AEROSIL RX300”, “AEROSIL NX90G” (manufactured by Nippon Aerosil Co., Ltd.), “AEROSIL R812”, “AEROSIL R812S”, “AEROSIL R8200” ( As mentioned above, Evonik Degussa Co., Ltd.) can be mentioned.

Still another configuration of the present invention is that, in the main configuration described above, the arithmetic average roughness Ra of the surface of the water-repellent layer in a state where the water-repellent film is adhered to the cup body after the insert molding is 50 nm or more. It is.
In addition, arithmetic mean roughness Ra of the surface of the water-repellent layer is measured according to JIS-B-0601 (2001) using AFM (atomic force microscope “Nanoscope 3a”, Nippon Beco, Digital Instruments). It is a thing.

  Arithmetic mean roughness Ra of the surface of the water repellent layer (hereinafter sometimes simply referred to as Ra. The measurement range is 25 micrometers × 25 micrometers). Types of contents, shape of cup body, contents In order to obtain practical water repellency and non-adhesiveness of the contents, Ra should be 50 nm or more. Is preferable.

The water repellent layer can be formed by applying a coating liquid prepared by dispersing hydrophobic oxide fine particles in a solvent such as ethanol to a base film and drying it. Ra can be adjusted mainly by the dispersion concentration of fine particles in the coating solution.
If the concentration is too low, even when Ra is about 100 nm at the time of manufacturing the water-repellent film, it may be compressed by molding pressure to 50 nm or less after insert molding, and practical water repellency will not be exhibited. End up.
The upper limit of Ra of the water-repellent layer after insert molding can be determined appropriately in consideration of the water repellency required according to the purpose of use, the coating property of the coating liquid, and the cost associated with the fine particles. Is.

Since the present invention has the above-described configuration, the following effects can be obtained.
By the water-repellent layer made of hydrophobic oxide fine particles, it is possible to effectively prevent the contents from adhering to the region where the water-repellent film on the inner surface of the cup body is adhered, and to continuously suppress the content for a long time.
In addition, since a water-repellent film prepared in advance may be insert-molded as an insert material, a post-process for applying and drying a coating liquid in which hydrophobic oxide fine particles are dispersed for each molded cup container is unnecessary. In addition, it is possible to impart water repellency, that is, non-adhesiveness of the content liquid with high productivity.

In insert molding, the water-repellent film, which is an insert material, is pressed against the cavity surface of the mold by a molten resin at high temperature and pressure, so that a part of the base film is softened or melted to form a cup body. The adhesion between the resin and the water-repellent film can be improved, the peeling of the water-repellent film during the use of the product can be effectively prevented, and the non-adhesive effect of the contents can be maintained stably for a longer period of time. be able to.

It is a perspective view which partially fractures and shows one Example of the cup container of this invention. It is a top view of the water-repellent film used for the cup container of FIG. It is sectional drawing which shows the layer structure of the water-repellent film used for the cup container of FIG. It is sectional drawing which shows the layer structure of the side surrounding wall of the cup container of FIG. It is a schematic explanatory drawing of the injection molding method which used the water repellent film as insert material. It is a table | surface which shows the test about a cup container, and a measurement result. It is a photograph which shows an example of the usage condition of the product which stored the contents. It is a perspective view of the water-repellent film shape | molded in the cup shape.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings while referring to variations thereof along examples.
FIG. 1 is a perspective view showing an embodiment of a synthetic resin cup container of the present invention. This cup container is an injection using a water repellent film 21 having a planar shape and a layer structure shown in FIGS. It is formed by molding.
The cup body 1 is a bottomed cylinder made of polypropylene (PP) resin, and has a cylindrical body portion 4 that gradually decreases in diameter downward, and a flange 3 is provided at the upper end of the body portion 4 in the shape of an outer casing. And has a bottom 5 at the lower end.

And the water-repellent film 21 is adhere | attached on the area | region covering the substantially whole height range of the internal peripheral surface 4wp of the side peripheral wall 4w which forms the trunk | drum 4 of the cup main body 1. FIG. In FIG. 1, the portion to which the water-repellent film 21 is bonded is indicated by a lattice-like cross hatch.
The water-repellent film 21 used as the insert material is cut into a fan shape as shown in FIG.

FIG. 3 is a cross-sectional view showing the layer structure of the water-repellent film 21, in which a water-repellent layer 23 made of hydrophobic oxide fine particles P is formed on the base film 22.
In this embodiment, the base film 22 is made of LDPE resin having a thickness of 60 micrometers, and hydrophobic silica fine particles having trimethylsilyl groups on the surface (for example, product names “AEROSIL RX200”, “AEROSIL”) as the hydrophobic oxide fine particles P. RX300 "," AEROSIL NX90G "(Nippon Aerosil Co., Ltd.)," AEROSIL R812 "," AEROSIL R812S "," AEROSIL R8200 "(Evonik Degussa) etc.) are used.
In addition, as this kind of water-repellent film 21, a TOYAL LOTUS coat film manufactured by Toyo Aluminum Co., Ltd. can be used.
Further, the base film 22 is not limited to the LDPE resin, but includes factors such as coating properties of hydrophobic oxide fine particles, adhesion or adhesion to the inner surface of the cup body 1, and generation of wrinkles during insert molding. In consideration of the above, the synthetic resin to be used can be appropriately selected.

Next, FIGS. 5A and 5B are schematic explanatory views of an injection molding method of the cup body 1 using the water-repellent film 21 as an insert material, and FIG. (B) shows a clamping state.
The injection molding die 31 has a core die 32 and a cavity die 33. The water repellent film 21 is adhered to the outer peripheral surface of the core portion 32a by a vacuum mechanism (not shown). An intake hole 36 for winding and fixing is provided.

Then, in a state where the mold is opened as shown in FIG. 5A, the water-repellent film 21 cut into a fan shape shown in FIG. 2 is formed on the outer peripheral surface of the core portion 32a of the core mold 32 by the vacuum mechanism. It is wound and fixed in close contact via the intake hole 36.
Next, as shown in FIG. 5B, the mold is clamped, and molten resin (PP resin in this embodiment) is injected and filled into the cavity 34 through the gate 35 disposed in the cavity mold 33. 1 can be molded.
In addition, as a method of fixing to the outer peripheral surface of the core portion 32a in a close contact state, a method of fixing by static electricity can also be employed.

  FIG. 4 is a cross-sectional view showing the layer structure of the side peripheral wall 4w of the body part 4 of the cup container of FIG. 1, showing the adhesion between the inner peripheral surface 4wp of the side peripheral wall 4w and the water-repellent film 21, In the insert molding, since the water-repellent film 21 as the insert material is pressed against the mold surface by the high temperature and pressurized molten resin that is injected and filled, a part of the LDPE resin that forms the base film 22 is softened. Alternatively, it can be melted to improve the adhesion with the inner peripheral surface 4wp of the cup body 1 made of PP resin, effectively preventing the water-repellent film 21 from peeling off during use of the product, The non-adhesion effect can be stably maintained for a longer period.

In addition, the water-repellent film 21 having the layer structure shown in FIG. 3 has good flexibility by making the base film 22 made of LDPE resin having a low softening temperature and relatively thin with 60 micrometers. And, as described above, coupled with the fact that the water repellent film 21 is tightly wound and fixed around the outer peripheral surface of the core portion 32a,
The water repellent film 21 can be adhered to the inner peripheral surface 4 wp of the cup body 1 in a good state without wrinkles.
If the base film 22 is too thin, handling of the film during insertion becomes difficult.

Next, a method for producing the water repellent film 21 having the layer configuration shown in FIG. 3 will be described.
Basically, the water-repellent film 21 is formed by applying a coating liquid in which hydrophobic oxide fine particles P are dispersed on one surface of an LDPE resin film forming the base film 22, and then evaporating the solvent. Manufactured dry.
3 will be described in detail.
A coating solution prepared by dispersing 30 g of hydrophobic oxide fine particles having a trimethylsilyl group on the surface (product name “AEROSIL”) in 1000 mL of ethanol was applied to one side of an LDPE resin film by a roll coating method, and then Drying was performed at 100 ° C. for about 10 seconds, and ethanol was evaporated to obtain a water repellent film 21.

  In addition, since the LDPE resin film as the base film 22 is partially softened in the ethanol drying process at 100 ° C. for about 10 seconds, the adhesion between the base film 22 and the water repellent layer 23 is increased. The adhesion force (fixing force) of the fine particles P can be further increased.

In addition, the formation process of the water repellent layer 23, that is, the method of attaching the hydrophobic oxide fine particles P is not limited to the above method.
For example, as described above, a large number of products of the hydrophobic oxide fine particles to be used are sold, and can be appropriately selected and used according to the purpose.
Various organic solvents such as alcohols such as ethanol, isopropyl alcohol, and hexyl alcohol, and glycols can be selected as the solvent for the coating solution, and the dispersion concentration of the fine particles can be appropriately selected.
In addition, the coating method is not limited to the roll coating method, and spray coating, gravure coating, bar coating, doctor blade coating, brush coating, powder electrostatics are considered in consideration of productivity and fine particle adhesion. A known method such as a method can be employed.

Next, in order to confirm the effect of adhering the water-repellent film 21 to the cup container of FIG. 1, as shown in the table of FIG. 6 in addition to the cup container of the above-described example (referred to as Example 1). The cup container of Example 2 in which the concentration of the coating liquid at the time of production of the water repellent film 21 was as low as 10 g and the cup container of the comparative example in which the water repellent film 21 was not adhered were prepared.
Observation of the water-repellent film corresponding to the hydrophobic oxide fine particles P in FIG. 4 of the water-repellent film 21 after bonding to the inner peripheral surface 4 wp of the cup body 1, arithmetic of the water-repellent layer 23 before and after bonding The measurement of average roughness Ra, the measurement of the contact angle of pure water, and the adhesion test of the contents which assumed the actual product were implemented, and the result was shown in the table | surface of FIG.

The Ra measurement method, pure water contact angle measurement method, and content adhesion test method are as follows.
(1) Measurement of arithmetic average roughness Ra of water-repellent layer 23 About the surface of the water-repellent layer 23, AFM (atomic force microscope "Nanoscope 3a" Nippon Beiko Co., Digital Instruments company) was used, and JIS-B-0601 ( Measured according to 2001).
(2) Test for measuring contact angle of pure water Inner peripheral surface 4wp of the test piece cut out from the side peripheral wall 4w of the cup container shown in FIG.
The contact angle was measured using a contact angle measuring device (contact angle meter “CA-D” manufactured by Kyowa Interface Science Co., Ltd.).
(3) Content adhesion test After filling a cup container with commercially available yogurt, leave it in a thermostatic bath at 5 ° C for 1 hour, then place the cup container in an inverted position and discharge the yogurt from the container. The residual adhesion state of yogurt to the inner peripheral wall 4wp was observed.
In the table of FIG. 6, the results of the adhesion test are indicated by ○, Δ, ×, where ○ is a state in which the adhesion of yogurt to the inner peripheral wall 4 wp is hardly seen, and Δ is a state in which a little adhesion is seen, X shows the state which has adhered over the whole area | region of the inner peripheral wall 4wp.

The results shown in the table of FIG. 6 are as follows.
(1) Peeling of water repellent As a result of observing the molded sample using a Keyence microscope VHX-100F, the water repellent was not peeled off in the cup container of Example 1, but the cup of Example 2 Some peeling was seen in the container.
(2) Arithmetic average roughness Ra of the water repellent layer 23
The Ra of the water-repellent film 21 before insert molding was about 120 nm in Examples 1 and 2 without much difference.
After molding, the value is about 54% before molding in the cup container of Example 1, and about 47% in the cup container of Example 2.
It is presumed that the arithmetic average roughness Ra is thus reduced after the insert molding because the water repellent layer 23 made of fine particles is compressed by the pressure during the injection molding of the cup body 1.

(3) Contact angle of pure water The cup container of Example 1 has 150 ° or more, that is, exceeds the measurement limit of the apparatus, and has sufficient water repellency. On the other hand, the contact angle of Example 2 is 137 °, which is lower than that of the cup container of Example 1. The contact angle of the cup container of the comparative example is 92 °.
(4) Adhesion of contents The adhesion of contents (yogurt in this test) has a correlation with the contact angle of pure water, and the contact angle is made sufficiently large as in the cup container of Example 1, that is, It can be seen that by sufficiently increasing the water repellency, the adhesion of the contents can be effectively suppressed, that is, the non-adhesion of the contents can be achieved at a high level.
However, the cup container of Example 2 also has a non-adhesive improvement compared to the cup container of the comparative example, and may be used depending on the type of the content liquid, the shape of the cup container, and the usage of the container product filled with the contents. Is at a level where

Next, in order to confirm the effect of the water-repellent film 21 in another usage mode of the actual product, the cup container of Example 1 and the comparative example described above,
A commercially available cheese fondue cheese was placed in the cup body 1 as the contents C, and a test was conducted in a microwave oven with an output of 600 W and a heating time of 1 minute 30 seconds.
FIG. 7A is a photograph of the cup container of Example 1, and FIG. 7B is a photograph of the heated state of the cup container of the comparative example taken from above.
In the cup container of the comparative example (FIG. 7B), it was confirmed that scorching S was generated on the cheese in the vicinity in contact with the inner peripheral wall 4 wp of the cup body 1.
On the other hand, in the cup container of Example 1 (FIG. 7 (a)), when compared under the same heating conditions, such a burning S was hardly seen.

The test results as described above show that in the cup container of the comparative example, the cheese as the content C adheres to the inner peripheral wall 4wp, and there is no movement due to convection of the content C heated in the vicinity of the inner peripheral wall 4wp. It is presumed that the burning S as shown in FIG.
On the other hand, in the cup container of Example 1, the adhesion of the content C in the vicinity of the inner peripheral wall 4 wp is suppressed by the water repellent effect of the water repellent film 21, and the content C moves and circulates by convection, and the occurrence of scoring S occurs. Is estimated to be suppressed.

As mentioned above, although the embodiment of the present invention has been described along the examples, the embodiments of the synthetic resin cup container of the present invention have been described in the examples so far as the variations thereof are individually described in the above description. It is not limited to.
Further reference to variations of embodiments of the present invention:
In the above embodiment, the cup body 1 is made of PP resin. However, depending on the purpose of use, it is made of a synthetic resin conventionally used in consideration of the use, such as polyethylene resin, polystyrene resin, or polyester resin. The cup body can be made.

Moreover, in the said Example, although the area | region which adheres the water-repellent film 21 was made into the internal peripheral surface 4wp of the side peripheral wall 4w of the cup main body 1, the water-repellent film 21 cut into circular shape was made into insert material, FIG. ) Can be adhered to the inner surface of the bottom wall 5w of the bottom portion 5 by being fixed in close contact with the lower end surface of the core portion 36a.
Of course, the water-repellent film 21 cut into a fan shape as shown in FIG. 2 and the water-repellent film 21 cut into a circular shape as described above are used as insert materials on both the inner peripheral wall 4wp and the inner surface of the bottom wall 5w. 21 can also be bonded.
Furthermore, the water-repellent film 21 is formed into a cup shape as shown in FIG. 8 by a method such as thermoforming, and the water-repellent film 21a formed into the cup shape is used as an insert material, as shown in FIG. The core portion 36a can be fitted and fixed in close contact, and the water repellent film can be adhered over the entire area of the inner surface of the cup body 1.

As described above, the synthetic resin cup container of the present invention is capable of effectively suppressing the adhesion of contents in a relatively simple process called insert molding and for a long time. As a cup container with excellent usability, it is expected to be widely used in the field of storing and using contents such as food.

DESCRIPTION OF SYMBOLS 1; Container main body 3; Flange 4; Body part 4w; Body wall 4wp; Inner peripheral surface 5; Bottom part 5w; Bottom wall 21; Water-repellent film 21a; Water repellent layer P; (hydrophobic oxide) fine particles 31; injection mold 32; core mold 32a; core 33; cavity mold 34; cavity 35; gate 36; ; Burnt

Claims (6)

The cup body (1) is formed by insert molding using a water-repellent film (21) in which hydrophobic oxide fine particles are adhered to one surface of the base film (22) to form a water-repellent layer (23). A synthetic resin cup container, wherein the water-repellent film (21) is adhered to a predetermined region of an inner surface via the other surface side of the base film (21). The synthetic resin cup container according to claim 1, wherein a water repellent film (21) is adhered to the inner peripheral surface (4wp) of the side peripheral wall (4w) of the body (4) of the cup body (1). The synthetic resin cup container according to claim 1 or 2, wherein a water repellent film (21) is adhered to the inner surface of the bottom wall (5w) of the bottom (5) of the cup body (1). 4. A synthetic resin cup container according to claim 1, wherein the hydrophobic oxide fine particles are hydrophobic silica. The synthetic resin cup container according to claim 4, wherein the hydrophobic silica has a trimethylsilyl group on the surface thereof. The arithmetic average roughness Ra of the surface of the water-repellent layer (23) in a state where the water-repellent film (21) is adhered to the cup body (1) after the insert molding is 50 nm or more. Or the synthetic resin cup container of 5.