JPH024631A - Plastic container for aseptic filling - Google Patents

Abstract

PURPOSE:To prevent the formation of bubbles when filling a container with the disinfected liquid contents by providing a neck part, a body part and a closed bottom part, all of which are formed integrally of plastic and composing said bottom of an annularly-shaped contacting part, a projecting part extending inwardly of the contacting part and a specific depressed part provided in the center of the projecting part. CONSTITUTION:A container 1 is composed of a neck part 2, a body part 3 and a closed bottom part 4, all of which are integrally formed. The closed bottom 4 is provided with an annularly-shaped contacting part 5, a projecting part 6 extending upwardly and inwardly of the contacting part and a depressed part 9 in the center of the projecting part. The depressed part 9 has a depth S of 2-20mm and an outside diameter D of 10-40mm and the height H of the projecting part 6 from the annularly-shaped contacting part 5 to the uppermost part 10 is within the range of 10-25mm. In a case where the depth S of the depressed part 9 is smaller than the above-mentioned, it becomes difficult to scatter the liquid impinging against the depressed part in the radial directions, whereas, when larger than the above- mentioned, air swirl is liable to take place upon the liquid impingement thereagainst. In a case where the outside diameter D of the depressed part 9 is smaller than the above- mentioned, the liquid from a filling nozzle 7 impinges against the bottom part other than the depressed part 9, i.e. the projecting part, resulting in the increased formation of bubbles.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a plastic container for aseptic filling, and in particular, by preventing the foaming of the liquid during filling, it is possible to prevent the overflow of the liquid. The present invention relates to a plastic container for aseptic filling that can suppress an increase in head space.

(Prior Art) Conventionally, a so-called aseptic packaging technique has been known as a packaging technique that has excellent flavor retention and preservability of liquid contents. This technique generally involves reducing the liquid contents to 1
Using the so-called ultra-high temperature sterilization method (UHT), which involves heating sterilization for a very short time of about 4 to 5 seconds at an ultra-high temperature of 40°C or higher, and then rapidly cooling it,
A separately manufactured packaging material is sterilized with a sterilizing solution, and the previously sterilized liquid contents are filled into the packaging material and sealed.

Since plastic containers, such as unstretched or biaxially stretched plastic bottles, generally have difficulty in heat resistance, the above-mentioned aseptic filling method can be said to be a packaging technique particularly suitable for this type of plastic container.

(Problems to be Solved by the Invention) Filling of liquid contents into a plastic container is of course carried out in a controlled atmosphere, but in order to keep the contact between the contents and the atmosphere in a short period of time, the filling time is In order to shorten the time and increase productivity, it is desired to increase the speed at which liquid contents are poured into plastic containers.

However, when conventional plastic bottles are filled with sterilized liquid contents, foaming occurs without exception, and this foaming causes the contents to spill out of the container.To prevent this, it is necessary to This requires a large head space, which is disadvantageous in terms of storage stability of the contents, container cost, and increase in packaging volume.

Therefore, an object of the present invention is to suppress foaming to a low level when filling the sterilized contents, and as a result, prevent the contents from overflowing to the outside of the container, and reduce the head space. To provide a plastic container for aseptic filling.

(Means for Solving the Problems) According to the present invention, the neck portion, body portion, and closed bottom portion are integrally molded from plastic, and the bottom portion includes an annular grounding portion, a protrusion inside the grounding portion, and a protrusion. and a recess provided at the center of the part, and the recess has a depth of 2 to 20 nm (S
) and an outer diameter (D) of 10 to 40+n+n,
There is provided a plastic container for aseptic filling in which bubbles are prevented, characterized in that the top of the protrusion has a height (H) from the grounding part of 10 to 25 mm.

(Function) In FIG. 2 showing an example of a conventional plastic container (bottle), this container 1 is composed of a neck portion 2, a body portion 3, and a closed bottom portion 4, which are integrally molded. In order to give the container self-reliance and to make it easier to sit on a support surface such as a table, the container is composed of an annular grounding part 5 and an upward protrusion 6 inside the grounding part. This container 1
When the liquid contents 8 are poured into the container from the filling nozzle 7 located above, the liquid flow 8 collides with the surface of the protrusion 6 at the bottom and is violently scattered in the radial outward direction (in the direction of arrow A). However, this water hits the wall surface of the container body 3 again and flows down, which is considered to be the cause of significant foaming in the liquid contents.

In FIG. 1 showing the general shape of a plastic container for aseptic filling of the present invention, this container 1 also consists of a neck 2, a body 3, and a closed bottom 4, which are integrally molded. It consists of a portion 5 and an upwardly directed protrusion 6 inside the grounding portion, and a notable feature is that a recess 9 is provided at the center of this protrusion. When a liquid content 8 is poured into the container from a filling nozzle 7 located above the container 1, this flow collides with a recess 9 provided at the center of the bottom of the container. Therefore, the liquid mainly flies in the radial direction (in the direction of arrow B) on the wall surface of the recess 9, the flow velocity near the bottom decreases, and the force with which it hits the container body wall is weakened, reducing air entrainment. This seems to suppress the generation of bubbles.

In FIG. 3 for explaining the dimensions of the bottom of the container of the invention, the recess 9 has a diameter of 2 to 20 mm, in particular 3 to 100 mm.
Depth of the shoe (S) and 10 to 40 mm, especially 20 to 3
It has an outer circumferential diameter (D) of 0 mm, and the height (I) of the topmost part 10 of the protrusion 6 from the annular grounding part 5 is 10 to 25.
It is also important that the diameter is in the range 15 to 20 mm.

That is, if the depth S of the recess 9 is smaller than the above range, it will be difficult to sufficiently scatter the colliding liquid in the radially inward direction, and the amount of bubbles generated will increase; When the bubble collides with the concave portion 9, the concave portion itself tends to entrain air, resulting in an increase in the amount of bubbles generated. Furthermore, if the outer circumferential diameter of the recess 9 is smaller than the above range, the liquid from the filling nozzle 7 will collide with the bottom other than the recess 9, that is, the protrusion, which tends to increase the amount of bubbles generated. It will be done. On the other hand, it is not preferable to make the outer circumferential diameter of the recess 9 larger than the above range because the slope of the wall surface of the recess 9 becomes small and the tendency of liquid to scatter to the side wall of the container body increases. Furthermore, if the height (H) is smaller than the above range, the self-supporting nature of the container tends to decrease, and the strength of the bottom (buckling strength, falling strength) tends to decrease.
On the other hand, if this height is larger than the above range, there will be problems in terms of moldability of the container, and the liquid will not flow smoothly to the deepest part of the bottom, causing air to be trapped, which is also undesirable.

According to the present invention, a concave portion is formed at the center of the bottom beam of the container, and its dimensions, S, D, and H, are set within the ranges described above, thereby reducing the entrainment of bubbles when filling the contents. ,
It is possible to prevent the contents from overflowing to the outside of the container during filling, and to reduce the head space of the container.

(Preferred Embodiment of the Invention) The plastic container for aseptic filling of the present invention is manufactured from a thermoformable thermoplastic resin by any means such as blow molding or stretch blow molding.

Suitable examples of resins constituting the container are low-1 medium- or high-density polyethylene, polypropylene, ethylene-propylene copolymers, ethylene-butene copolymers, ionomers, ethylene-vinyl acetate copolymers, ethylene. - Olefin copolymers such as vinyl alcohol copolymers: polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate; polyamides such as nylon 6, nylon 6.6, and nylon 6.10; polystyrene, styrene; Styrenic copolymers such as butadiene block copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer (ABS resin); Vinyl chloride such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer Vinylidene chloride resins such as vinylidene chloride-acrylic copolymers; Acrylic copolymers such as polymethyl methacrylate and methyl methacrylate/ethyl acrylate/acrylonitrile copolymers; polycarbonates, etc. These thermoplastic resins may be used alone or in the form of a blend of two or more. Furthermore, the plastic container may have a single layer structure or a laminated structure of two or more layers, for example, by simultaneous melt extrusion.

Of course, the melt-mouldable thermoplastic resin may contain pigments, antioxidants, antistatic agents, ultraviolet absorbers,
1ff of additives such as lubricants! Or two or more types in a total amount of 0.001 parts to 5.0 parts per 100 parts by weight of resin.
It can also be added within the range of 0 parts. For example, in order to reinforce this container, fiber reinforcing materials such as glass fiber, aromatic polyamide fiber, carbon fiber, bulb, cotton linter, etc., powder reinforcing materials such as carbon black, white carbon, glass flakes, aluminum, etc. 1 fffi type or 2 of flake-like reinforcing materials such as flakes
The above types can be blended in a total amount of 2 to 150 parts by weight per 100 parts by weight of the thermoplastic resin, and for the purpose of increasing the amount, heavy to soft calcium carbonate, mica, talc,
Kaolin, gypsum, clay, barium sulfate, alumina powder,
The total amount of one or more types of silica powder, magnesium carbonate, etc. per 100 parts by weight of the thermoplastic resin is 5.
There is no problem even if it is blended in an amount of 150 parts by weight according to a recipe known per se.

Molding into a container can be carried out by a blow molding method or a stretch blow molding method using a blow mold corresponding to the bottom shape described above. In the blow molding method, one or more resins are extruded or coextruded through a ring-shaped die to produce a molten parison, and this molten parison is pinched off with a split mold, and a fluid is blown into the inside to form a predetermined shape. Form into a container. In addition, in stretch blow molding, a parison in the shape of a pipe or a cylinder with a bottom is formed using an extrusion molding method or an injection molding method,
After the parison is preheated to a stretching temperature, it is stretched in a blow mold in the axial direction of the container, and simultaneously or subsequently, it is blow stretched in the circumferential direction by blowing fluid. Although generally not necessary, a biaxially molecularly oriented stretch blow molded container can also be heat set under restraint conditions to improve its heat resistance.

Most preferably, the plastic container for aseptic filling of the present invention is formed by stretch blow molding a thermoplastic polyester such as polyethylene terephthalate (PUT). In addition, blow molded containers and stretch blow molded containers made of polypropylene or a laminate of polypropylene/ethylene-vinyl alcohol copolymer/polypropylene are also available.
It is preferable for the use of the present invention.

It has already been mentioned above that in the container of the present invention, the dimensions S, D and H of the bottom should be within a certain range, but it is desirable that these dimensions also have a certain relationship, and the S/H ratio should be 0. .08 to 0.8, especially 0.2 to 0.5, and S/D 0.05 to 0.8, especially 0.2 to 0.5
It is better to be within the range of

In the container of the present invention, as best shown in FIG. Having a cross-sectional shape in which a curvature surface having a radius of curvature R and a downwardly convex curvature surface occupying the center of the recess 9 are connected closer to the center than the top 10, further reduces the entrapment of bubbles. It is preferable to reduce the amount. Further, the ratio R/R' is preferably in the range of 0.5 to 5, particularly 2 to 3.

In order to use the plastic container of the present invention for aseptic filling, the container is sterilized by being immersed in a sterilizing solution known per se or by being sprayed with a sterilizing solution. As the sterilizing liquid, an aqueous solution containing peracetic acid and/or hydrogen peroxide is preferably used. After sterilization, the liquid is removed by air blowing, etc., the container is rinsed with washing water, dehydrated again, and then supplied to the aseptic filling area.

On the other hand, the liquid contents are sterilized by heating for a short time at extremely high temperatures in a heat exchanger (U) IT equipment (general temperature: 130°C).
(from several seconds to 2 minutes) and then rapidly cooled, and then quickly filled into a container through a filling nozzle. A sterilized cap is then placed on and fastened in the same manner as the container to form a sterile, filled and sealed package.

(Example) A preform with a bottom was manufactured by injection molding polyethylene terephthalate.
After preheating to a temperature of ℃, the material was stretched by 2 times in the axial direction and 3.5 times in the circumferential direction to obtain an inner volume of 1500 ml.
! , a stretch-blown container was manufactured.

At this time, the bottom shape and dimensions of the container are shown in Figures 4 to 6 and 1.
It was as shown in the table.

Table 1 Liver Shape SD R A Figure 4 Omm Omm 10111
1118 Figure 5 3ra124mI1117In
IIIC Figure 6 3mm 26mm 21mm After sterilizing these containers with a sterilizing solution and washing them with water, they are fed to an aseptic filling machine, and the sterilized black coffee is heated to 25°C and 7°C.
The foam height and foam volume at the time of filling were measured. The results are shown in Tables 2 and 3.

8 is liquid content; 9 indicates a concave portion.

Claims (3)

[Claims] (1) A neck part, a body part, and a closed bottom part are integrally molded from plastic, and the bottom part consists of an annular grounding part, a protrusion inside the grounding part, and a recess provided at the center of the protrusion, and the recess has a depth (S) of 2 to 20 mm and an outer diameter (D) of 10 to 40 mm, and the top of the protrusion has a height (H) from the grounding part of 10 to 25 mm. A plastic container for aseptic filling that prevents foaming and is characterized by: (2) The plastic container according to claim 1, which is formed by stretch blow molding of thermoplastic polyester. (3) The closed bottom of the container has a radius of curvature R', has an upwardly convex curvature surface extending from the protrusion through the top to the recess, and has a radius of curvature R and occupies the center of the recess. 2. The container according to claim 1, wherein the container has a cross-sectional shape in which the downwardly convex curved surface is connected to the center side of the top.