JPS6344477A - Vessel for filling bean curd - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A.9 Objective of the Invention (Field of Industrial Application) The present invention relates to a container for filled tofu, specifically a package consisting of a lid and a container called an inner pack of a filled tofu package.
After filling the soy milk and coagulant, it is sealed by heat sealing, followed by a coagulation process at 90°C or higher and a cooling process to form tofu, which can be easily heat sealed by hand when purchasing and using the product. This relates to containers that can be opened by peeling off the parts.

(Prior art) Conventionally, high impact styrene (hereinafter referred to as HI
Two types of materials are used: PS) and polypropylene (hereinafter referred to as PP).

Filled tofu is made by adding coagulants (magnesium chloride, sium, etc.) to the soy milk in advance.
Calcium sulfate, glucono delta lactone, calcium chloride, etc.) are filled into a container, the periphery of the container and the lid are sealed by heat sealing, and the filled tofu is then coagulated in hot water of 90℃ or higher. Since the package, i.e. the container, must have a certain degree of heat resistance,
Recently, it can be said that the mainstream is to use PP container packaging, which has better heat resistance.

The sealing between the lid and the container is achieved by heat sealing, and there are two types: complete sealing, in which similar materials are heat-sealed together, and incomplete sealing, in which dissimilar materials are heat-sealed.

In the former case of heat sealing of similar materials, that is, HIP
S lids and HIPS containers, or PP lids and PP containers, have sufficient sealing strength because they are heat-sealed together, but when opening the seal, the heat-sealed part must be It is so strong that it cannot be peeled off by human hands.

Therefore, it is necessary to cut the lid material along the opening with an edged tool such as a knife or kitchen knife, but such a method is cumbersome and poses a risk of injury due to carelessness.

The latter, which utilizes the non-fusion properties of dissimilar materials,
HIPS is a new technology on the market.
For both PP and PP containers, the lid material is a composite sealant whose main component is ethylene-vinyl acetate polymer (hereinafter referred to as EVA). It is designed to have a beer strength that allows it to be peeled off with force, so even when opening the package after filling it with contents and heat-sealing it,
Like the former, the seal can be easily opened by peeling off the heat-sealed portion at the interface without using a knife or the like.

However, the latter disadvantage is that heat sealing through soymilk having a relatively large particle size is extremely difficult, and the heat sealing strength varies widely, causing concerns about sealing performance. If there is a partial seal or a very weak seal and peeling occurs during the distribution process, the number of viable bacteria will increase significantly even during the indicated best-before period, and there is a risk that the product will be out of specification.

Secondly, the easy-peel sealant used for the latter is mainly composed of EVA, so it has poor heat resistance, and has a temperature of 9"C, which is the standard temperature for solidifying filled tofu according to Ministry of Health and Welfare Ordinance No. 270.
X: Cannot adequately respond to conditions that require sterilization for 40 minutes or longer, or with a method with an equivalent or greater efficacy.

Generally, the softening temperature of EVA is 80"C or less, so 90℃×
Processing for 40 minutes is difficult and requires processing for a long time at a lower temperature than the above processing temperature, which poses a major problem in terms of productivity.

The present invention was made in view of the above-mentioned problems, and its objectives are to improve the resistance to soybean milk contaminants, and to improve the heat resistance of retort processing at a coagulation sterilization temperature of 90"C or higher, and in some cases 100"C or higher. This is a unique product for filled tofu that is not found in conventional products, as it has a structure that allows the heat-sealed part to be easily peeled off by hand without using a knife, and the seal can be opened with the peeled surface clean. It provides a container.

B6 Structure of the Invention (Means for Solving Problems) The present inventor's research has revealed that the sealant layer is made of a material that can be strongly fused by heat sealing and can be cohesively peeled off by manual peeling force when opening the sealant. It has been found that when used in layers, it is effective for achieving the above-mentioned purpose.

When a sealed container is manually opened, a part of the fused sealant layer undergoes cohesive failure and is torn off from the sealant layer and transferred to the other side of the sealant. This is the so-called cohesive peeling, which occurs when the hard and brittle resin is generally damaged by distortion or impact. In addition to the cohesive failure of the sealant layer itself, the cohesive failure that is likely to occur when cracks occur, the core layer is extremely thin (less than 5 μm in thickness), and the elongation of the core layer with respect to the tensile stress with the adjacent layer is important. The present invention has been completed based on the finding that when there is a large difference in the difference between resins, resins of the same type tend to coagulate and peel.

That is, in the filled tofu container according to the present invention, the innermost layer on the container side has a tensile strength of 150 to 350 kg and an elongation. There is a sealant layer of polypropylene or modified polypropylene having a cohesive failure property of 10 to 15%, the thickness of the core layer is 5 μm or less,
The thickness is preferably 3 to 5 μm, and the layer adjacent to the core layer has a tensile strength of 250 kg/am” or more.

General-purpose polypropylene with an elongation of 200% or more and no cohesive failure property is used.

In the present invention, the resin having cohesive failure properties for the innermost layer of the container is a simple propylene-ethylene copolymer with an ethylene component of about 3% by weight, or a 20-polymer polyethylene or ethylene-α-olefin copolymer in the P4 area. A modified polypropylene mixed with the following components is used.

The test method for tensile strength and elongation is JIS-6758.
by.

To describe in more detail the resin having cohesive failure properties in the innermost layer of the container, it has a specific gravity of 0.91, a melting point of 150°C, a crystallinity of 55%, and a melt flow rate of 55%.
e) = 50, elongation 10%, tensile strength 350kg
Isotactic polypropylene, which has high thermal fluidity, high crystallinity, low elongation and rather brittle properties, is suitable. When the polymer is mixed in an amount of 20% by weight or less, each resin is mixed using a mixer, a blender, etc. by means commonly used in the art.

The purpose of modifying the isotactic polypropylene with such polyethylene or ethylene-α-olefin copolymer is to lower the cohesive strength and increase the impact strength than in the case of the polypropylene alone. However, since the heat resistance of polyethylene or ethylene-α-olefin copolymer is inferior to that of a single substance, the mixing ratio is limited to 20% by weight based on the heat resistance treatment temperature in the filling tofu production process. In addition, the upper limit is 20% by weight from the viewpoint of maintaining the heat sealability through soymilk, which is essential in the case of filled tofu, that is, the fusion sealability that is most effective against contamination sealability.

The floating polypropylene used has a specific gravity of 0.918° and a melting point of 10.
It is a general-purpose extrusion laminate/togelade with a temperature of 8°C, MI (melt 1ndex) = 5, and the ethylene-α-olefin copolymer has a specific gravity of 0.88, a Vicat softening point of 80°C, and a MI (melt 1ndex) = 3.
．． 6 general-purpose modification resin.

The tensile strength of polypropylene modified by blending is 150~3QOkg/an'', and the elongation is 15
The tensile strength is preferably 250 to 50%.
300kg C is mixed so that the elongation is in the range of 20 to 35% for heat resistance and strength.

A good balance can be obtained in heat seal strength, beer strength, etc.

In the present invention, other conventional additives may be added to the modified polypropylene as a material for the sealant layer containing the modified polypropylene, such as encapsulants, lubricants, fillers, reinforcing agents, and antioxidants.

In the present invention, the sealant layer having cohesive failure properties is located in the innermost layer of the container, and the layer adjacent to the core layer has a tensile strength of 250k.
A general-purpose polypropylene used in the industry as a material for a sheet or sealant layer that does not have cohesive failure properties and has an elongation of 200% or more is used.

Therefore, the method of laminating the thin sealant layer with cohesive failure property of the innermost layer of the container and the layer adjacent to the core layer is set by the resin for the innermost layer of the container and the layer adjacent to the core layer that are respectively input into two extruders. This is a method using a so-called co-extrusion molding machine, in which the materials are melt-kneaded at a certain temperature and then joined in a molten film state.

Since the net amount of tofu put into the container is generally 400 g or more, the container itself must have a certain degree of strength, so the thickness of the plastic sheet before forming the container is generally 400 μm or more. .

Since one of the purposes of the container for filled tofu of the present invention is to be suitable for retort processing at 100°C or higher, polypropylene, which has excellent heat resistance, is used as the base material. The base material and the innermost layer of the container may be the same, and in this case, the base material and the innermost layer of the container may be the same, and in this case, a two-layer composite sheet with a sheet thickness of 400 μm or more is made using the above-mentioned coextruder. Thereafter, a container is formed by an appropriate container forming method such as vacuum forming or pressure forming.

In some cases, the film for the innermost layer of the container and the film for the adjacent layer are directly coextruded and laminated onto a single polypropylene sheet made to a predetermined thickness. In this case, the appropriate thickness of the laminate is 20 to 50 μm as the thickness of the two-layer film.

The laminate sheet made by this method is made into a container using the same container forming method as the two-layer sheet.

In the present invention, as the container base material, other materials having excellent heat resistance such as polymethyl pentene sheet, crystalline polyester sheet,
Heat-resistant polyethylene sheets can also be used, but the price of the base material itself is high, and the so-called dry lamination, which uses an expensive adhesive to bond the innermost layer film of the container and the co-pressed film with the adjacent film, Since the method is expensive, it can be said that it is difficult to use except for special purposes.

The base material of the lid material for sealing the container for filled tofu according to the present invention is preferably a heat-resistant and strong film such as polyester or nylon, and the sealant of the lid material is the innermost sealant of the container. This is a polypropylene film that is widely used in the industry and can be bonded to the lid base material by dry lamination as described above.

(Function) As shown in FIG. 1, the container for filled tofu of the present invention has a container 1 having a thin film 2 as an innermost layer having cohesive failure property.
A polypropylene film 7 that can be fused and sealed with the thin film 2 of the innermost layer of the container, is composed of a film 3 adjacent to the film 2, and a container base material 4, and the lid material 5 is a polyester film or a nylon film, and the base material 6 is a polypropylene film 7. It is constructed by joining them with adhesive.

Therefore, if soy milk and coagulant are filled into the container 1 described above, the lid material 5 is placed on the periphery of the container 1, and the two are heat-sealed, the container 1 will be completely sealed by welding the sealant films 2 and 7. Therefore, if the soybean milk is coagulated and cooled in this state, it will coagulate and the filled tofu as shown in FIG. 1 will be completed.

Therefore, when using this filled tofu, when the unsealed part of the lid material 5 is grasped with fingers and pulled up, the innermost layer film 2 at the periphery is coagulated and peeled off from the adjacent film 3, as shown in FIG. It transfers to the film 6 side of the lid material 5 and is opened as shown in the same figure. At this time, the innermost layer film 2 of the container 1 is partially enlarged as shown in the third factor, and the adjoining layer is Although it remains attached to three sides of the film, there is little fluff or hangnails and the peeled surface is clean.

(Example) Example 1゜M F R (melt flow rate) = 9
(g/10m1n) of polypropylene (melting point 6
0℃, specific gravity 0.90, tensile strength 450kg/cm! ,
A sheet with a thickness of 400 μm (elongation 450%) is made by the F die casting method, and this is used as a container base material.A) Polypropylene (melting point 15
0°C9 specific gravity 0.90. Crystallinity 55%, tensile strength 35
0kg/cm”, elongation 10%)
b) Polypropylene (melting point 155℃, specific gravity 0.90, crystallinity 47%, tensile strength 400kg/
e'ffl"l elongation 300%) co-pressed laminate (a)
Polypropylene (238 m thick) b) Polypropylene (30 μm thick on laminate side)] Next, a filled tofu container was made from this composite polypropylene sheet by vacuum forming.

Fill the resulting container with the blended soymilk liquid and fill it with a tofu sealer while using a lid material made in advance (stretched nylon film 158 mm thick/general-purpose polypropylene film 40 μm thick).
It was sealed by heat sealing through thick and soy milk.

This filling container was heated at 90℃ x 40 minutes, 100℃ x 30 minutes, 1
As a result of coagulation and sterilization at each treatment temperature of 10°C x 20 minutes, no abnormalities such as bag breakage or appearance were observed. The thin film layer of the innermost layer of the container for processed products coagulated and peeled off, and while it was transferred to the sealant surface of the lid material, the peeled surface was able to be opened in a very clean state.

The opening force after this treatment is 1.5 to 1.8 (kg/15
M) and was stable.

Example 2 The same 400 μm thick polypcoporin sheet as in Example 1 was coated with the same a) polypropylene and polyethylene (M I (melt 1nd
x) = 5, specific gravity 0.918°, melting point 108°C] 20
Co-press laminate of C) mixed resin and b) polypropylene with weight% C) modified polypropylene 231 m thick/b) polypropylene (laminate side) 30 μm thick, and use this composite polypropylene sheet for filling tofu in the same manner as in Example 1 I made a container.

The resulting container was filled with the blended soymilk liquid and sealed with the lid material used in Example 1 prepared in advance while being filled with a tofu sealant.
Treatments were performed at 0°C for 30 minutes and at 110°C for 20 minutes.

No abnormalities such as bag breakage or appearance were observed under all processing conditions.
Compared to the case of Example 1, the opening force was 1.0 to 1.3 (kg/1
It was small (5 on) and easy to peel off. The innermost layer of the container made of modified polypropylene was coagulated and peeled off and transferred to the lid sealant, and the coagulated and peeled surface had a very clean surface without fluff or hangnails.

Example 3 The innermost layer of the container made of the mixed resin with polyethylene of Example 2 was made of ethylene-α-olefin copolymer (MI-3,6, specific gravity 0.88, Vica
Example 2 with a mixed resin of 20% by weight (softening degree 80°C)
Exactly the same test was carried out, and similar to the case of Example 2, good results were obtained.

- However, under the conditions of 100°C x 20 minutes, the opening force was 0.7 (kg/15mm), which caused some concern. Opening force is 90°C for 40 minutes.

1.0 to 1.2 (kg
/151T! III).

After putting the filled and sealed products of Examples 1 and 2.3 in the refrigerator for 24 hours, they were taken out and a drop test was attempted from a height of 1 m. The stability rankings were Example 3, Example 2, and Example 1.
Met.

Comparative Example 1 In Examples 1 and 2.3, when the thickness of the innermost layer of the container having the cohesive and peeling function was increased to 5 μm or more, the cohesive and peeling property became extremely unstable at a thickness of 10 μm, causing fuzzing and cracking. etc. were conspicuous, and the surface condition impaired the commercial value.

Comparative Example 2゜When the mixing ratio of polyethylene or ethylene-α-olefin copolymer to polypropylene in Examples 2 and 3 was increased to 20% by weight or more, in the case of polyethylene, at 30% by weight, soymilk Contamination sealing property through
100 because it becomes extremely unstable and the heat resistance also decreases.
Many bags were broken during the treatment at °C for 30 minutes and at 110 °C for 20 minutes.

Even when the mixing ratio was increased to 25% by weight, no complete improvement was observed.

In the case of ethylene-α-olefin copolymer, the contamination sealability was not as affected as in the case of polyethylene, but 2
110℃×20 due to decrease in heat resistance at 5% by weight mixing ratio
The rate of bag breakage was high after 5 minutes of processing.

Comparative Example 3゜The innermost layer of the container having cohesive releasability in Example 1 was made of polypropylene (MFR-40, melting point 1
50°C, specific gravity 0.90.

Crystallinity 49%, tensile strength 400kg/cm", elongation 3
0%), the opening force is 2.0 (kg/15m).
1), it was very difficult to open and the peeling surface was unsatisfactory as it was fluffy and had hangnails.

The measures of Example 2 or 3 were taken using this resin as a base, and although an improvement in ease of opening was observed, fuzziness on the peeling surface and
Sakikure etc. could not be improved.

Comparative Example 4゜A co-press laminate of the innermost cohesive release layer and the adjacent layer applied to the container side in Examples 1 and 2.3 was made with the same structure, and a stretched nylon film with a thickness of 15 μm was used as each lid material. Composite was performed on the surface using adhesive.

A general-purpose single polypropylene container for filled tofu, in which each lid material had been prepared in advance, was filled with blended soymilk using a sealer for filled tofu and sealed by heat sealing through the soymilk.

This filled container was heated at 90°C for 40 minutes for each container.
As a result of coagulation sterilization carried out at treatment temperatures of 00° C. for 30 minutes and 110° C. for 20 minutes, no abnormalities such as bag breakage or appearance were observed.

However, when the lid was opened using the sealant of Example 1, the opening force was strong and the lid was sometimes cut. When the opening force is measured, it is 2.0 to 2.5 (kg /
15m).

The lids using the sealants of Examples 2 and 3 also had a fairly strong opening force and were difficult to peel off, but were better than the lids using the sealants of Examples.

However, because the cohesive release film was transferred to the periphery of the container, it turned white and became slightly fluffy and scratchy, posing a problem with its commercial value.

The cohesive and peeling function of the container sealant part of the invention has a high degree of crystallinity,
A thin film of polypropylene having cohesive failure properties due to low elongation or a modified product of the resin is bonded to an adjacent layer of polypropylene that does not have cohesive failure properties, and the thick polypropylene of the container base material (the above-mentioned adjacent Since the polypropylene layer is laminated with a container base material (which may also be used as a container base material) to form a container, its functions can be fully demonstrated. In other words, in the case of a sealer for filled tofu that is fused and sealed by heat sealing from the lid surface, the fact that the cohesive release layer film is on the container side means that the film may become distorted or thin due to excessive heat or physical strength. It is said to prevent things from happening.
That is, it is effective in terms of retaining an effective film, and the film is likely to coagulate and peel because a thick, hard container is difficult to deform due to stress when peeling and opening. That is, it has the effect of being easy to open.

The layers of each container are fused and sealed with films and sheets made of polypropylene or modified polypropylene, which have excellent heat resistance.
Can withstand retort treatment at temperatures above 0°C.

By fusion-sealing the lid material and the container, it exhibits excellent adaptability to contents such as soy milk, which have large particle diameters and are easily coagulated by heat, so-called contaminant sealing properties that are difficult to seal.

In addition to tofu, it can also be used for contents containing non-solutions that are difficult to seal with contaminants, such as chawanmushi and egg tofu, meat sauce, beef stew, curry liquid, etc.

Having a thin cohesive release film on the container side has the above-mentioned effect when opening the package, but it also improves the product effect in that it cleans without lint or cracking.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a filled tofu container according to the present invention, which is sealed together with the contents in a state in which the peripheral edge of the container is heat-sealed with a lid material. FIG. 2 is a cross-sectional view showing the same as the above during peeling and opening. FIG. 3 is an enlarged sectional view of the circular portion in FIG. 2. In the figure, 1 is a plastic container, 2 is a sealant having cohesive failure properties, 3 is an adjacent layer, 4 is a base material of the container, and 5 is a sealant having cohesive failure properties.
6 is a sealant having no cohesive failure property, and 7 is a base material of the lid material. Procedural Amendment (Voluntary) September 4, 1986 Filled Tofu Container 3, Relationship to the case of the person making the amendment Patent application address Address: 1, 2-n, Kanda-Awaji-cho, Chiyoda-ku, Tokyo Name: Sunny Chemical Industry Co., Ltd. Representative Chiaki Matsuki Each column 1 of "Claims" 1 "Detailed Description of the Invention" in the specification and the column 1 "Claims in the specification" will be corrected as shown in the attached sheet. 1. On page 7, line 5 of the same page, ``15%'' should be corrected to ``50%.'' 1. On page 9, line 5 of the same page, replace "polypropylene" with "
Corrected to "polyethylene." 1. On page 14, line 7 of the same page, the statement ``1 melting point 60℃'' has been replaced with ``1
60 degrees Celsius,” he corrected. 1. “F die-casting method” in lines 9 and 10 of the same page as above.
Correct the statement to read "T die-casting method." Attachment ``In a container for filled tofu that is sealed by heat-sealing the periphery of the plastic container with a lid, the innermost layer on the container side has a tensile strength of 150 to 350 kg and an elongation of 10 to 350 kg.
There is a polypropylene or modified polypropylene sealant with a film thickness of 5 μm or less that has fusion properties with sub% polypropylene and has cohesive failure properties, and the layer adjacent to the core layer has a tensile strength of 250 kg/cm or more and an elongation. degree 200%
Is there a general-purpose product with more cohesive failure properties? If "L" is □, the container side sealant and lid material described above have a tensile strength of 25 kg/cm or more and an elongation of 20
"Container for filled tofu, characterized by being able to fuse and seal the filled tofu with a general-purpose polypropylene sealant that does not have cohesive failure of 0% or more through appropriate heat sealing" Procedural amendment (voluntary) Showa October 23, 1961 2, Name of the invention: Filled tofu container 3, Relationship with the case of the person making the amendment Patent application location: 2-23-11 Kanda-Awaji-cho, Chiyoda-ku, Tokyo, from the bottom of page 12 of the specification Middle East It is added between the 5th line and the 4th line as described later. "Containers and lids, especially those with gas barrier properties, can be composited with so-called films with good gas barrier properties, such as vinylidene chloride or polyvinyl alcohol." Procedural Amendment (Toge) 1988 July 27th 2, Name of the invention: Filled tofu container 3, Relationship with the case of the person making the amendment Patent application Place of residence
1, 2-chome, Kanda-Awaji-cho, Chiyoda-ku, Tokyo
Sunny Chemical Industry Co., Ltd. 4, agent postal code 1 Rororo 5, column 1 for ``Detailed explanation of the invention'' in the specification subject to amendment, 1 for line 3 on page 13 in the specification 1 for base material 6'' Lines 4 to 5 of the same page say 1 Polypropylene film 7, 1 Polypropylene film 6, and Line 10 of the same page says 1 Film 2 and 7. film 2
and 6,” he corrected. 1. On page 20, line 13 of the same article, it says, “When the opening force is measured, 2
．． It was 0 to 2.5 (kg/cm2). ” Delete Toaruwo. that's all

Claims (1)

[Claims] In a container for filled tofu that is sealed by heat-sealing the peripheral edge of the plastic container with a lid, the innermost layer on the container side has a tensile strength of 150 to 350 kg/cm.
^2. There is a polypropylene or modified polypropylene sealant with a film thickness of 5 μm or less that has fusion properties with polypropylene with an elongation of 10 to 15% and has cohesive failure properties, and the layer adjacent to this layer has a tensile strength 250kg/cm^
There is a general-purpose polypropylene that does not have cohesive failure properties with an elongation of 2 or more and an elongation of 200% or more, and a tensile strength of 250 kg/cm^2 or more and an elongation of 200% or more, which is comprised of the container side sealant and lid material. A container for filled tofu, characterized in that a general-purpose polypropylene sealant having no cohesive failure property is fused and sealed via the filled tofu by appropriate heat sealing.