JP3133665B2 - Fruit storage container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite sheet on which a polyethylene terephthalate film is laminated and a container for storing fruit formed from the composite sheet. More specifically, the present invention relates to a composite sheet for reusing recycled polyethylene terephthalate and a fruit container formed from the composite sheet. Specifically, when molded into a fruit tray having a large number of storage recesses, the composite sheet is excellent in transparency, easily wrinkled, and less likely to be damaged during use, and obtained by molding the sheet. The present invention relates to a fruit storage container provided.

[0002]

2. Description of the Related Art As a material for a fruit storage container, for example, a fruit tray having a large number of storage recesses, a polyvinyl chloride resin sheet, an expanded polystyrene sheet, a pulp mold and the like are usually used. I have. However, molded articles made of a polyvinyl chloride resin sheet are broken when they are stacked and removed one by one after transportation, and have poor transparency, and there is a processing problem when discarding used articles. Was. A foamed polystyrene sheet molded article has an advantage of being excellent in cushioning property, but has a problem that it is bulky when the molded articles are stacked because it is thick. Further, the pulp molded article has a problem in that the strength is reduced due to the influence of moisture absorption or moisture generated from fruits.

On the other hand, polyethylene terephthalate (hereinafter referred to as PET) is colorless and transparent, has excellent mechanical properties such as tensile strength and impact resistance, and has good heat resistance and weather resistance. Molded into various shapes and used in daily necessities. Of these, blow molding liquid containers are widely used, and are widely used as bottles for drinking water, soy sauce, cosmetics, and the like. This bottle is
Since it is only used temporarily as a container for selling goods, it is useless after consuming the goods at home. Thus, these containers are discarded, but remain without weathering because of their good weather resistance, thus polluting the environment. Therefore, it has been desired to collect and reuse these containers.

[0004] When a PET sheet is formed to form a PET molded body, what is on the periphery of the molded part is called a trimming loss and is scrapped.
The scrap is generally formed in an amount equal to or more than 30% of the molded body, and sometimes equivalent to the molded body. So PE
It has been desired that scrap generated during the formation of the T-sheet is also reused.

[0005] The PET film recovered from such a viewpoint and a newly manufactured PET film (virgin PET film)
Composite film laminated with
This is disclosed in Japanese Utility Model Publication No. 6-6911. However, the composite sheet described in this publication simply uses recycled PE
Since only the T film and the virgin PET film were laminated, when this was used as a packaging container for fruits and the like, the strength was too high, and the fruits and the like stored during transportation were sometimes damaged. It is necessary to adjust the strength so that fruits and the like are not damaged during transportation.

[0006] Also, only with recycled PET film,
Fruit trays such as apples are not strong enough to be used.
After storing an apple or the like, it sometimes tears when both ends or opposite corners are held with both hands.
To prevent this, the tear strength must be 200 kgf / cm ²
And a container tensile strength of 400 kgf or more is required.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems, and as a result, have solved the problems of conventional polyvinyl chloride resin sheets, expanded polystyrene sheets, pulp molds and the like, and have succeeded in mass production. The present invention was found by finding a composite sheet capable of recycling the generated waste PET.

Thus, according to the present invention, the thickness is 50 μm.
One side or both sides of a recycled polyethylene terephthalate film having a thickness of 10 μm to 10 μm.
A polyethylene terephthalate film of 0 μm is laminated, and a recycled polyethylene terephthalate film is
The thickness ratio with the polyethylene terephthalate film is
Molding and forming a composite sheet in the range of 5: 1 to 20: 1
And has a bottom compressive strength of 0.5 kgf to 1.5 kgf.
A container for storing fruits is provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, PET used in the present invention
The PET is preferably composed of 80% by mole or more, particularly 90% by mole or more of the acid component, composed of a terephthalic acid component, and 80% by mass or more of the diol component, particularly 90% by mol or more of the ethylene glycol component. Further, as for PET, modified PET can be used within a range not losing its essence, for example, isophthalic acid, p-β-oxyethoxybenzoic acid,
A dicarboxylic acid component such as naphthalene-2,6-dicarboxylic acid, diphenoxyethane-4,4-dicarboxylic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid or an alkyl ester derivative thereof, and propylene glycol; PET comprising glycol components such as 4-butanediol, neopentyl glycol, 1,6-hexylene glycol, cyclohexane dimethanol, and ethylene oxide adduct of bisphenol A
Etc. can also be used.

The composite sheet of the present invention is characterized in that
ET recycled PET film and virgin PET
It has a configuration in which a film is laminated. Here, the main structure of the composite sheet of the present invention is a recycled PET film. The recovered PET generally undergoes thermal deterioration, and thus has a reduced intrinsic viscosity (IV value). Further, when it is formed into a film, it is further subjected to a heat history, so that the intrinsic viscosity is reduced. When a film is formed by using an extruder using the recycled PET whose intrinsic viscosity has been reduced, it is softer than a virgin PET film. If this softened film is formed into a container for storing fruits such as apples, it has an effect of preventing fruits such as apples from being damaged during transportation.

[0011] recycling PET film of the invention, recycling even amorphous PET even crystalline PET PE
T can be used as a material . The intrinsic viscosity (IV value) of the PET used is set to 0.1 in terms of heat resistance and impact resistance.
Those having 6 or more, preferably in the range of 0.6 to 1.0 can be suitably used. The present invention has the advantage that since the resin layer having the above-described structure is laminated by a co-extrusion method, transparency, gloss, moldability, and the like are good, and there is an advantage that scrap can be effectively used, and physical properties and appearance are excellent. A sheet is obtained.

The recycled PET film of the present invention is
The whole may be recovered PET, and when the intrinsic viscosity (IV) is too low, virgin PET may be added. Virgin PET to be added is preferably up to 50%.
Also, in the present invention, it is conceivable that the recycled PET film has been deteriorated due to a number of thermal histories.
The virgin PET film is laminated on one or both sides of the recycled PET film so that the effect of deterioration during use does not appear.

Here, the thickness of the recycled PET film is 50 to 500 μm, the thickness of the virgin PET film is 10 to 100 μm, and the total thickness is 60 to 500 μm.
It is necessary to be 600 μm. Recycled PET
The thickness ratio between the film and the virgin PET film is 5:
It is preferred to be in the range of 1 to 20: 1. Here, when the recycled PET film is thin, the composite sheet tends to be too hard and difficult to mold, and when thick, the moldability tends to be inferior.

Further, the composite sheet of the present invention preferably has a tear strength of 200 kgf / cm ² or more and a tensile strength of 400 kgf or more. When molded into a fruit storage container using a composite sheet that satisfies such tear strength and tensile strength, the fruit storage container is torn during use, or after storing the fruit, hold both ends or opposite corners with both hands. It can be prevented from tearing when it is released.

When the composite sheet of the present invention is used as a fruit storage container provided with a large number of fruit storage recesses used for, for example, apples, pears, peaches, etc., the fruits and the like may be damaged. In order to prevent the wrinkles from being received, it is necessary to make the bottom of the fruit storage container strong enough to cause wrinkles. For this reason, the compressive strength at the bottom of the container for storing fruits is set to 0.5 kgf or more.
It is preferable to keep it at about 1.5 kgf, more preferably at about 0.7 kgf to 1.3 kgf.

For example, when apples and the like are stored in a container for storing fruits and transported, 5 kg of fruits are stored in the container for storing fruits, and the fruits are stacked in two tiers and put into a cardboard case with 10 kg. It is pre-vacuum pre-cooled in order to avoid damage to apples and the like due to the temperature rise. Water droplets adhere to the surface of pre-cooled apples or the like. Further, since fruits such as apples are breathing, moisture is generated by breathing during storage or transportation. The presence of this moisture may accelerate the ripening of the fruit or cause it to rot. However, in the present invention, as described above, the compressive strength at the bottom of the fruit storage container is set to 0.5 kgf to 1.5 kgf.
When apples and other fruits are stored, wrinkles are generated at the bottom of the container for storing fruits during transportation, and the occurrence of the wrinkles causes water drops to drop, and the water generated from the fruits is removed from the wrinkles. The secondary effect of preventing the acceleration of ripening of the fruit can be obtained by storing in the portion.

Further, by making the compressive strength in the longitudinal direction of the container for storing fruits 0.5 kgf to 1.2 kgf and the compressive strength in the short direction 1.0 kgf to 2.0 kgf, a soft feeling can be obtained. This has the effect of preventing damage to fruits such as apples inside.

[0018]

【Example】

Example 1 FIG. 1 shows a composite sheet of the present invention. In FIG. 1, 1 is a recycled PET film, 2 is a virgin PET film laminated on both sides of the recycled PET film 1, and 3 is a composite sheet. The composite sheet 3 has a total thickness of 180 μm, and the recycled PET film 1 has a thickness of 140 μm.
μm, and the virgin PET film 2 is 20 μm.

The tensile strength and tear strength of this composite sheet are as follows:
As shown in Table 1. For comparison, the strength of a polyvinyl chloride resin sheet (PVC) having the same thickness is shown.

[0020]

[Table 1]

The test method was as follows. Tensile strength T
Was measured at a pulling speed of 50 mm / min using a dumbbell-shaped No. 1 shape of JIS K6301, and the maximum load F until cutting was measured during the pulling was determined by the following equation. T = F / Wt (where W is the width of the dumbbell and t is the thickness of the dumbbell) The tear strength T2 is the value of B described in 9.2 of JIS K6301.
With a dumbbell shaped, pull at a pulling speed of 50 mm / min.
The maximum load F before cutting was measured and determined by the following equation.

T 2 = F / t (where t means the thickness of the dumbbell) The composite sheet 3 is used as a material and the registered design No. 65777 is used.
It was formed into an apple tray (fruit storage container) provided with 16 concave portions shown in No. 1 and having a semicircular, cross-shaped, or radial shape and projecting outward from the bottom surface, which is smaller than the bottom surface of the concave portion. Table 2 shows the tensile strength of this apple tray, and Table 3 shows the compressive strength (longitudinal, width, bottom). For comparison, Table 2 shows the strength of an apple tray similarly molded from a polyvinyl chloride resin sheet having the same thickness, and Table 3 shows the strength of the apple tray also including the pulp mold.

[0023]

[Table 2]

The maximum tensile load means the maximum load measured up to the point where the tray is gripped at a corner and pulled at a pulling speed of 500 mm / min until cutting is performed.

[0025]

[Table 3]

The compressive strength was measured as follows. The longitudinal direction and the width direction are the respective loads when compressed in the longitudinal direction and the width direction by 30 mm from the facing flange in the rectangular opening of the tray, and the bottom is 30 m from the bottom of the tray storage section.
This is a measurement of the load when compressed by m. Sixteen apples with a total weight of 5 kg were stored in this tray, stacked in two tiers, placed in a cardboard case, vacuum precooled, and transported by car from Nagano Prefecture to Tenri City, but the apples were damaged. I didn't. In addition, wrinkles were generated at the lower part of the tray during transportation, and a small amount of water considered to have been generated from the apples and the like was found at the lower part of the wrinkles. However, no water was attached to the apple and there was no damage. .

Example 2 The thickness of the composite sheet was 500 μm for the recycled PET film and 100 μm for the virgin PET film.
A tray was formed by molding in the same manner as in Example 1 except that the tray was changed to m, and was too hard to be used as a tray for apples or the like. Therefore, recycled PET film and virgin PE
When the transport test of fruits such as apples was conducted by variously changing the thickness of the T film, a composite sheet in which the thickness of the recycled PET film was 80 μm to 250 μm and the thickness of the virgin PET film was 20 μm to 70 μm was a preferable range. It turns out.

[0028]

The composite sheet of the present invention, when formed into a fruit storage container having a large number of recesses suitable for storing a large number of fruits in isolation, has excellent transparency and produces wrinkles. An easy-to-use fruit storage container can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a composite sheet of the present invention.

[Explanation of symbols]

 1 Recycled PET film 2 Virgin PET film 3 Composite sheet

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-25330 (JP, A) JP-A-5-16297 (JP, U) JP-A-6-6911 (JP, Y2) (58) Survey Field (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B65D 65/00-65/46

Claims (4)

(57) [Claims] On one side or both sides according to claim 1] Recycling polyethyleneterephthalate having a thickness of 50μm~500μm phthalate film, polyethylene terephthalate film having a thickness of 10μm~100μm are laminated, recycled polyethylene
Renterephthalate film and polyethylene terephthale
The ratio of the thickness to the heat film is in the range of 5: 1 to 20: 1.
0.5 kgf ~
Features 1.5kgf bottom compressive strength
Fruit storage container. 2. The fruit storage container according to claim 1, wherein the intrinsic viscosity of the recycled polyethylene terephthalate material of the recycled polyethylene terephthalate film is 0.6 or more .
Container . 3. The composite sheet has a weight of at least 200 kgf.
The fruit storage container according to claim 1, which has a tear strength of / cm ^2.
Bowl . 4. The container according to claim 1, wherein the composite sheet has a tensile strength of 400 kgf / cm ² or more.