JPH0123112B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial application field] Cylindrical packaging using vinylidene chloride resin film, mainly for processed meat foods such as meat and fish, processed dairy products such as cheese and butter, and confectionery such as Western cakes and jelly. Regarding the body and its improvement technology. [Prior Art] A cylindrical package made of vinylidene chloride resin film is widely known. For example, automatic filling and packaging machines such as those commercially available as ADP (trade name, manufactured by Asahi Kasei Corporation) or KAP (trade name, manufactured by Kureha Chemical Co., Ltd.) are used, and are generally disclosed in, for example, Japanese Patent Publication No. 55-34044. In other words, a flat long film is continuously bent so that both sides thereof overlap, and the overlapping parts are thermally welded (sealed) to form a cylindrical film. After filling the packaged contents, a series of automatic, bag-making, filling, and ligating operations are performed, including sealing (wire ligation) with appropriate spacing, and cutting each piece into cylindrical packages. It is also widely known that it can be manufactured using One drawback of this package is that the outer film is made strong so that it can withstand various stresses from handling such as transportation and conveyance, and maintains the spoilage and contamination resistance of the contents. For this reason, it is difficult to take out the contents, especially to take out the contents and use them for the purpose without using a knife or the like. Therefore, even though it is known to have excellent preservability and hygienic properties, there are restrictions such as the inability to apply this package to, for example, toy confectionery that children can enjoy and eat. On the other hand, as a method for facilitating the removal of the above-mentioned outer skin film, Japanese Patent Publication No. 51-8080 and
There is a technique disclosed in Publication No. 49-19021. In short, a strip-shaped material that is stronger than the outer skin film is attached to a part of the cylindrical body or a part of the seal line, and by pulling this strip-shaped material, a part of the cylindrical film is pulled. The proposal is to provide an easy-to-open part that can be torn and used as a cut end of the outer skin film. However, with this technique of creating an easy-to-open part, it is extremely difficult to guarantee the achievement of a nearly 100% probability of forming a tear-off cut. However, it has not reached the point where it is widely used. The main reason for this is that easy opening installation requires advanced welding equipment and equipment that can set and manage conditions with high precision.
This is because, while technology is required, it is not possible to add costs to the packaging itself that correspond to its technological value. [Problems to be solved by the invention] A novel cut is formed which is completely different from the conventional idea of forming a cut, that is, by bending and curving the package in the longitudinal direction, the surface film is cut and the cut is formed. to make it easier to take out the contents by using
The objective is to be able to provide packaging bodies that have such functions without impairing other properties that are required for packaging bodies, such as gas barrier properties, impact resistance, and sealing resistance. . [Means for solving the problem] The differences from conventional cylindrical packaging bodies using vinylidene chloride resin films are as follows: (1) The vinylidene chloride resin that forms the film has no plasticity. The agent content is 4% by weight or less. A vinylidene chloride-methyl acrylate copolymer resin containing 4 to 7% by weight of methyl acrylate component is used. (2) The contents of the package are filled with non-flowable substances at a filling rate of 90%.
% or more. This is a combination of requirements (1) and (2) above. The contents of the present invention will be explained in detail below using drawings and the like. FIG. 1 is a model diagram showing the cutting process in which when the cylindrical package of the present invention is bent and curved in the longitudinal direction, the film on the outer periphery of the curve begins to tear and cut. This FIG. 1 is for explaining how to form a cut to form an opening corresponding to the effect of the present invention. In FIG. 1, an initially straight cylindrical package (indicated by a dotted line) 1 is curved at both ends 2, 2 so that its longitudinal center is curved at an angle θ. ′ in close proximity. If the angle θ reaches approximately 60 degrees or less, the film itself is often cut along with the cutting of the contents, but Fig. 1 shows the assumed state immediately before cutting. That is, the solid line represents a situation in which the film is stretched along the outer periphery of the content being curved, and a crack is generated in the film itself as the content is broken. In the package of the present invention, the breaks and cuts are used to cut the film into thin strips along the circumference of the package, and to push out the contents from the cross section of the cuts, making it easy to take out the contents. The purpose is to promote In this case, the contents must be a non-flowing substance that does not flow at room temperature, preferably a solid that does not flow, and the filling rate, expressed as the ratio of the true volume of the contents to the volume of the package, must be 90% or more. . The reason for this is to bend the package and break the film along with the contents, and to ensure that the break occurs easily.For example, if the contents are fluid and the filling rate is less than 90%. This makes it extremely difficult for the film to break. Furthermore, if the contents are a fluid such as a liquid, the problem arises that when the film breaks, all the contents are squeezed out at once and scattered over a wide area. Become. Next, the characteristic of the resin composition that gives the above-mentioned breaking property is that vinylidene chloride-methyl acrylate copolymer resin containing 4 to 7% by weight of methyl acrylate component is made into a film with a plasticizer content of 4% by weight or less. The goal is to make it happen. First, the methyl acrylate component is 4 to 7% by weight.
The reason for this is that the film itself has gas barrier properties, impact resistance, tear resistance of the sealed part, etc., which are necessary for reliably preserving the contents when packaged. This is to satisfy the required quality balance. In the vinylidene chloride-methyl acrylate copolymer resin that forms the basis of these film properties,
The need for the plasticizer content to be 4% by weight or less is such that, for example, if the plasticizer content is 4% by weight or more, the flexibility of the obtained film will increase, making it difficult to obtain the effect of bending and breaking the package. . In general, the amount of plasticizer in the film resin should be small from the viewpoint of other than the desired breaking effect, such as reducing gas barrier properties and increasing surface bleed of the plasticizer. However, as long as vinylidene chloride resin is used as the target resin for the film, the amount of plasticizer cannot be easily reduced in order to maintain extrusion film formability industrially. This fact shows that methyl aliclate has 4
The present invention, which targets vinylidene chloride resins containing up to 7% by weight, is no exception. In the present invention, the following effects are utilized to achieve both the above-mentioned extrusion film formability and reduction in the amount of plasticizer. Figure 2 is an experimental diagram, where the horizontal axis is the initial plasticizer content in the resin, the vertical axis is the proportion (wt%) of the plasticizer that can be dissipated in the extrusion film forming process, and the solid line is the invention of the present invention. This is a summary of the experimental results for the target resin. The results shown in FIG. 2 indicate that the resin targeted by the present invention has a function capable of dissipating a relatively large amount of plasticizer during the extrusion-film forming process. In the present invention, by utilizing this function, a large amount of plasticizer is used during extrusion and film forming to overcome the poor film forming properties of the vinylidene chloride-methyl acrylate copolymer resin. %
Hereinafter, we have succeeded in achieving a plasticizer content of desirably 3% by weight or less to a stage called a substantially non-plastic state. The vinylidene chloride-methyl acrylate copolymer resin referred to in the present invention is
The weight average molecular weight (by GPC method) is in the range of 70,000 to 250,000, and the ratio to the number average molecular weight determined by the same GPC method (i.e., weight average molecular weight ÷ number average molecular weight) is 2.0 to 3.0. Preferably within that range. More preferably, the weight average molecular weight is in the range of 80,000 to 130,000, and the ratio to the number average molecular weight (weight average molecular weight ÷
The number average molecular weight) is preferably in the range of 2.0 to 2.4. The weight average molecular weight and number average molecular weight here are
It is a value calculated in terms of porstyrene obtained by the method described in Japanese Patent Application No. 59-240483 (Japanese Patent Application Laid-open No. 61-120719), that is, the GPC (gel permeation chromatography) method. The plasticizer used in the present invention refers to a liquid plasticizer known as a plasticizer for vinyl chloride resin. Among them, from the viewpoint of food safety and hygiene, liquid plasticizers are carefully selected from aliphatic dibasic acid esters, citric acid esters, fatty acid esters, polyesters, etc., and preferably diisobutyl adipate, dibutyl sebatate, and acetyl chloride. Tributyl acid, etc.
More preferably, the above plasticizer and diisobutyl adipate are used in combination (for example, the diisobutyl adipate component is 50% by weight or more). Qualitative and quantitative determination of plasticizers can be carried out using the solvent extraction method described in publications on analysis, such as "Polymer Analysis Handbook" (edited by the Japanese Society for Analytical Chemistry, 1985).
This can be carried out by a method using a gas chromatograph and a mass spectrometer. The plasticizer dissipation rate is the ratio (wt%) of the amount of plasticizer (B) dissipated during the extrusion-film forming process to the initial content (A), that is, the plasticizer dissipation rate (wt%) = A / B × 100 = Amount of plasticizer in raw resin (weight %) - Amount of plasticizer in film (weight %) / Amount of plasticizer in raw resin (weight %) ×
It is 100. The evaluation method and evaluation scale used in the present invention are shown below. (a) Oxygen gas permeability ASTM D-3985 compliant [Unit: cc/m ²・24Hr・atm at 20℃] Evaluation scale evaluation symbol Standard value ◎; Less than 3 c.c. ○; 3 c.c. or more to 5 c.c. Less than △; 5 c.c. or more to less than 10 ^c.c. Value: ◎: Less than 3g ○: 3g or more and less than 5g, △: 5g or more and ^less than 10g Evaluation scale evaluation symbol Standard value ◎; 1000Kg or more ○; 700Kg or more - less than 1000Kg △; 400Kg or more - less than 700Kg Evaluation scale evaluation symbol expressed by value Standard value ◎; 10Kg-cm or more ○; 7Kg-cm or more - less than 10Kg-cm △; 5Kg-cm or more - less than 7Kg-cm ×; less than 5Kg-cm (e) Seal part Bag breakage strength After sealing, one side of the cylindrical film is ligated with aluminum wire, an air nozzle is inserted from the other side, and the part 150 mm away from the ligation is heated at 120℃ using a rubber tube to prevent air from leaking. The bag was immersed in the liquid, and then air pressure was gradually applied until it burst, and the gauge pressure at the time of bursting was measured and determined as the bag-breaking strength. [Unit Kg/cm ² ] Evaluation scale evaluation symbol Standard value ◎; 0.8Kg or more ○; 0.5Kg or more - less than 0.8Kg △; 0.3Kg or more - less than 0.5Kg ×; less than 0.3Kg (f) Packaging bending test Sensory test evaluation scale evaluation symbol when a cylindrical package is bent in the longitudinal direction as shown in Figure 1 Standard value ◎; Cut ×; Not cut (g) Thickness Conforms to ATSM-D374 [Unit: μ] Hereinafter, the content of the present invention will be explained in detail using experimental examples and examples. In addition, the base resin used in the following experimental examples and examples has a component ratio of vinylidene chloride component and methyl acrylate component of 97:3 [vinylidene chloride (wt%): methyl acrylate (wt%)]
Same hereafter], 96:4, 95:5, 93:7, 92.5:7.5
It is a vinylidene chloride-based resin in which 1% by weight of epoxidized linseed oil is added as a heat stabilizer to each of the five types of copolymers. This base resin can be produced by the method described in Japanese Patent Application No. 59-240483. Experimental Example 1 A mixture of equal amounts of diisobutyl adipate and dibutyl sebatate (both liquid plasticizers) was added to the base resin in which the ratio of vinylidene chloride component to methyl acrylate component was 96:4 at 2% by weight, 4% by weight. % by weight, and 6% by weight were added and mixed to obtain three types of resins. These resins are produced using the usual extrusion film forming method, that is, they are supplied to a melt extruder, melted, extruded into a tube through the slit of an annular die attached to the tip of the extruder, supercooled, and then subjected to inflation. This tubular film is pinched and crushed into a flat shape, and introduced into a heating furnace whose temperature is controlled to 100℃ with hot air. After being subjected to heat treatment (pass length of about 10 m), it is crushed with cooling rollers. Cool and wind a film with a fold width of 1300 mm and a film thickness of 40 microns (two layers).
It was wound onto a bobbin at a rate of 20m/min. These films were slit into 22-row strips of 56 mm width and wound onto a bobbin with the pinch creases removed at both ends. For the three types of films obtained, the amount of plasticizer remaining in the film was measured, and the plasticizer dissipation rate (% by weight) was determined. The results are shown in Figure 2. The results shown in Figure 2 indicate that the vinylidene chloride-methyl acrylate copolymer resin composition of the present invention has the property that the plasticizer in the raw material resin escapes during the extrusion, film forming, and heat treatment steps. It shows. Example 1 The component ratio of vinylidene chloride component and methyl acrylate component is 97:3, 96:4, 95:5, 93:7,
A mixture of diisobutyl adipate and dibutyl sebatate (both liquid plasticizers) (diisobutyl adipate) was added to each of the base resins with a ratio of 92.5:7.5.
70% by weight: dibutyl sebatate 30% by weight) 3.5~
5% by weight was added and mixed. Using these resins, the same extrusion film slitting method conditions as Experimental Example 1 were used, except that the treatment temperature in the heating furnace was changed to 110°C compared to the extrusion film slitting method described in Experimental Example 1. Five types of films (~) with a film thickness of 40 microns (two films stacked) and a width of 56 mm were prepared, and each film was wound onto a bobbin. The amount of residual plasticizer in these films is approximately 3% by weight. The physical properties of the five types of films obtained were evaluated by the method described in the text. Next, these films were suspended on ADP [trade name, automatic filling and packaging machine manufactured by Asahi Kasei Corporation], and the traveling speed of the film was 25 m/min, and the surface pressure (pressure) of the electrode was
Sealed under 300g conditions and made into a cylindrical bag (folding diameter 25mm)
did. The electrode plate current at this time was set at the midpoint of the sealable range. The bag tear strength of the sealed portion of the manufactured bag product was examined using the method described in the text. Next, from among the above-mentioned films, films with a component ratio of vinylidene chloride component and methyl acrylate component of 96:4 and 93:7 were selected, and for comparison and comparison, Saran film [trade name,
Manufactured by Asahi Kasei Corporation; thickness 40 microns (2 layers) width 56
mm] was suspended on ADP, the contents were filled with cheese while being made into a cylindrical bag under the same conditions as above, and wire ligatures were applied to form a sealed package (diameter 15 mm x length).
150mm x weight 24g). The filling rate was 95% in all cases. The resulting package was subjected to a bending and cutting test using the method described in the text. The results of the film physical properties and the tear strength of the sealed portion are shown in Table 1, and the results of the package bending test are shown in Table 2. According to the results in Table 1, when the product of the present invention is made into a package with gas barrier properties, impact resistance, tear resistance of the sealed part, etc., the packaging is necessary to reliably preserve the contents. It can be seen that it has the required quality as a material.

[Table] According to the results in Table 2, the cylindrical package of the present invention can be formed by forming a new cut, which is completely different from the conventional concept of cut formation, that is, by simply bending and curving the package in the longitudinal direction. It can be seen that the surface film can be cut with a cutter and the contents can be taken out through the cut.

[Effects of the present invention]

By having the above-mentioned structure, the present invention forms a novel cut completely different from the conventional concept of cutting, and uses the cut to make it easier to take out the contents. It can be said that this is an excellent invention that can provide other required qualities of a package, such as barrier properties, impact resistance, and tear resistance of the sealed portion, without impairing them.

[Brief explanation of drawings]

FIG. 1 is a model diagram illustrating the effects of the present invention;
FIG. 2 is an experimental diagram explaining the technical contents of the present invention, and is a characteristic diagram showing the usefulness of each obtained film. Symbol explanation: 1... Cylindrical packaging.

Claims (1)

[Scope of Claims] 1. A vinylidene chloride resin film in which the inside of the cylindrical vinylidene chloride resin film is filled with a non-flowable content, and both ends of the cylindrical film are sealed. (1) The vinylidene chloride resin has a plasticizer content of 4% by weight or less and a methyl acrylate component of 4% by weight or less.
~7% by weight vinylidene chloride-methyl acrylate copolymer resin. (2) The filling rate of the contents is 90% or more. A cylindrical packaging body made of a vinylidene chloride resin film, which is characterized in that when the cylindrical body is curved and bent in the longitudinal direction, the film on the surface of the packaging body can be cut.