JP6083592B2 - Synthetic resin cup container and manufacturing method thereof - Google Patents

Description

The present invention relates to a synthetic resin cup container and a method for manufacturing the same , which are intended to suppress adhesion of contents.

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 A

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,
On one surface of the base film, a water repellent film as an insert material having a water repellent layer composed of hydrophobic oxide fine particles having a surface arithmetic average roughness Ra of 50 nm or more,
It is said that it is adhered to a predetermined region on the inner surface of the cup body via the other surface side of the base film.
Such a synthetic resin cup container is manufactured by insert molding using the water-repellent film as an insert material.

  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 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. Examples of commercially available products corresponding to this include “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.

In the above main configuration, the arithmetic average roughness Ra of the surface of the water-repellent layer made of hydrophobic oxide fine particles was measured using AFM (Atomic Force Microscope “Nanoscope 3a”, Nippon Beco Co., Digital Instruments Co.). It is measured according to B-0601 (2001).

The arithmetic average 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) is the type of contents, the shape of the cup body, and the contents. are those which may be determined by using embodiments of the container products filled with objects, in order to obtain non-adherent practical water repellency, and the contents to one general are you with 5 0 nm or more.

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 (insert molding) 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 , that is, insert 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.
Repellent film 21 is used as the insert material, using those cut in a fan plane 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 (insert molding) of the cup body 1 using the water-repellent film 21 as an insert material. FIG. The mold open state, (b) shows the mold clamped state of the mold 31 .
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, at the die opening state as shown in FIG. 5 (a), the vacuum mechanism, the outer peripheral surface of the core portion 32a of the core mold 32, the water repellent properties were cut in a fan plane shape shown in FIG. 2 film 21 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 the water repellent film 21 to the outer peripheral surface of the core portion 32a in a close contact manner, 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, winding adhesion shape on the outer peripheral surface of the water-repellent film 21 as described above the core portion 32a, I can coupled with being fixed,
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 adhering effect of the water-repellent film 21 for a cup container of FIG 1, in addition to the cup container of the embodiment according to the description (. To Example 1), as shown in the table of FIG. 6 In addition, a 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 reduced to 10 g and a cup container of a comparative example to which the water repellent film 21 was not adhered were prepared.
Observation of the water repellent film 21 corresponding to the hydrophobic oxide fine particles P in FIG. 4 of the water repellent film 21 after being bonded to the inner peripheral surface 4wp of the cup body 1 and the water repellent layer before and after bonding by insert molding 23. Measurement of the arithmetic average roughness Ra of the surface 23, measurement of the contact angle of pure water, and a content adhesion test assuming actual products were carried out, and the results are shown in the table of FIG.

The measuring method of arithmetic average roughness Ra, the measuring method of the contact angle of pure water, and the method of the adhesion test of the contents 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 ( It was measured according to 2001).
(2) Test for measuring contact angle of pure water The test surface was the inner peripheral surface 4wp side of the test piece cut out from the side peripheral wall 4w of the cup container shown in FIG. 1, and the contact angle measuring device (contact angle meter “CA-D The contact angle of pure water was measured using “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 surface of the rear body 4 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 to the inner peripheral surface of the yogurt is hardly seen, Δ is a state in which the adhesion is slightly seen, X shows the state which has adhered over the whole area | region of an internal peripheral surface .

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
Ra of the water-repellent layer 23 in the insert molding before the water-repellent film 21 may be either not much difference in Examples 1 and 2 was about 120 nm.
After the insert molding, the value of the cup container of Example 1 is about 54% before molding, and the value of the cup container of Example 2 is about 47%.
Oite after insert molding, why the arithmetic mean roughness Ra of the thus water-repellent layer 23 surface is small, at the time of injection molding of the cup body 1, the water-repellent layer 23 made of fine particles by the pressure of the molten resin, group It is presumed that the unevenness of the surface is reduced by being compressed by pressing from the back side through the material film 22 .

(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 of the upper surface in contact with the inner peripheral surface 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, a cup container of Comparative Example adheres to the contents of C in a cheese inner peripheral surface 4Wp, no movement by convection of the inner contents upper surface has been heated in the vicinity of the peripheral surface 4Wp C, It is presumed that a burning S as shown in FIG.
On the other hand, the cup container of Example 1, adhesion of the contents C of the inner circumferential surface 4wp vicinity is suppressed by water repellency of the water repellent film 21, convection by moving content C, S scorching circulating It is presumed that the occurrence of was 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. the lower end surface of the core portion 3 2 a) of, by fixing the contact shape, can be bonded to the inner surface of the bottom wall 5w of the bottom 5.
Of course, a water-repellent film 21 which is cut in a fan plane shape as shown in FIG. 2, the water-repellent film 21 which was cut to the circular shape as the insert material, both the inner surface of the side wall 4w and the bottom wall 5w, repellent it is also possible to bond the water-soluble film 21.
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. The core portion 3 2 a can be fitted and fixed in close contact, and the water repellent film 21 a 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.

1; container body 3; flange 4; barrel 4w; side peripheral wall 4Wp; inner circumferential surface 5; bottom 5w; bottom wall 21; water repellent film 21a; (molded into a cup-shaped) water repellent film 22; base material film 23; water-repellent layer P; (hydrophobic oxide) particles 31; injection mold 32; core mold 32a; core unit 33; the cavity metal mold 34; cavity 35; gate - DOO 36; air suction hole C; content Object S;

Claims (6)

On one surface of the base film (22), there is a water repellent film (21) as an insert material having a water repellent layer (23) composed of hydrophobic oxide fine particles having an arithmetic average roughness Ra of 50 nm or more. A synthetic resin cup container, which is adhered to a predetermined region of the inner surface of the cup body (1) via the other surface side of the base film (22).
The synthetic resin cup container according to claim 1, wherein the 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 the 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 water-repellent film (21) formed by attaching hydrophobic oxide fine particles to one surface of the base film (22) to form a water-repellent layer (23) is used as an insert material, and by insert molding, the cup body (1) Adhering the water-repellent film (21) to a predetermined region on the inner surface via the other surface side of the base film (22) when the arithmetic average roughness Ra of the surface of the water-repellent layer (23) is 50 nm or more A method for producing a synthetic resin cup container.