JP2003104456A - Food packaging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a food packaging method of excellent oxygen permeability, retort property, flavor property, and preservability in which a packaging vessel can be used in an oven or a microwave oven as it is. SOLUTION: In this food packaging method for packaging a food by using a vessel sealed by using a lid member with a polyester sealant for easy peel laminated on the vessel formed of crystallized polyester, the oxygen concentration in the vessel in half a year after the content is packaged is <=3.0%.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to heat resistance and low odor.
Made of crystallized polyester which is required to have properties such as
Regarding lid material with low oxygen permeability that is made by laminating container and seal material
Food packaging method. [0002] 2. Description of the Related Art Polyester, especially polyethylene tereph
Crystalline polyester resin represented by tarate (PET)
Is widely used as a polymer for sheets and films, including fibers.
Have been used. In addition, microwave ovens for home use and ovens
Food containers that can withstand high temperatures are used due to widespread use
Have been. At present, heat-resistant food trays
PET (hereinafter referred to as C-PET) has been put to practical use.
You. [0003] However, C-PET containers are made of acid.
Although it has a characteristic of light permeability, its adhesion to the lid material
There is no product that can be put to practical use, and it is used as a normal temperature distribution container.
Had not been. An olefin resin is used as a normal temperature distribution container.
Of container and EVOH layered container and lid material with high barrier property
Mounting method is used, but the
The odor due to the fin resin transfers to the food inside and flavors
It has the disadvantage that a drop occurs. [0005] The inner layer is made of an amorphous polyester resin.
The above disadvantages are eliminated while maintaining the sealing property with the lid material
However, heat resistance is reduced and microwave ovens and ovens
You will not be able to use it. [0006] SUMMARY OF THE INVENTION
To solve the conventional problems of
As a method, use a C-PET container and a
Of packaging method for food using lid material laminated with wood
did. It can be distributed at room temperature and can be used in microwave ovens and ovens.
To provide a food packaging method that can be used
It is. [0007] SUMMARY OF THE INVENTION The present invention provides a crystallized
Container sealed with a lid in a container made of polyester
Packaging method using a container, after 6 months in the container
It is packaged so that the oxygen concentration of it is 3% or less.
Food packaging method. [0008] DESCRIPTION OF THE PREFERRED EMBODIMENTS C-PET container used in the present invention
The vessel may have either a single-layer structure or a multilayer structure. example
For example, polyethylene terephthalate having an intrinsic viscosity of 0.70 dl / g or more
92-98% by weight of phthalate resin and polyolefin resin
A container having a structure of 2 to 8% by weight. Or inherent viscosity
Polyethylene terephthalate with a degree of 0.70 dl / g or more
Resin as a base material, substantially 0.1 to 10% by weight of inorganic particles
And a surface layer consisting of 0.01 to 1.0% by weight of wax,
Polyethylene terephthalate with a viscosity of 0.70 dl / g or more
Resin base material and at least polyolefin resin 2
~ 8% by weight, inorganic particles and wax are the same as the surface layer
0.1 to 10% by weight of inorganic particles and 0.1% of wax.
An inner layer which may or may not contain from 0.01 to 1.0% by weight
A container having a structure. In addition, polyethylene terephthale
The acetaldehyde (AA) content of the salt resin is
50 ppm or less, further 30 ppm or less, particularly
Is preferably 15 ppm or less, and the amount of acetaldehyde is low.
The lower the better, the better, but 0.001 for economical production
It is preferably at least ppm. Furthermore, polyethylene
The cyclic trimer (CT) content of the lentephthalate resin is
5000 ppm or less in terms of taste and prevention of mold contamination
It is preferable that 2000 ppm or more is economical.
preferable. Furthermore, these polyethylene terephthalates
The sheet obtained from the sheet resin is based on JIS method K7133.
The heat shrinkage in the measurement was 2 to 8%.
The crystallinity of the container formed by the metal-based sheet is 10
Preferably it is 40%. Base material for polyester container
Is a polyethylene terephthalate
(PET), homopoly of polyethylene naphthalate (PEN)
Of course, Ma is partially isophthalic acid isophthalic
Acid, adipic acid, diphenylcarboxylic acid, diphenyle
-Tercarboxylic acid, sebacic acid, naphthalenedicarboxylic acid
Substitution with one or more other dicarboxylic acid components such as acids
And part of the ethylene glycol component
, Triethylene glycol, hexamethylene glyco
, Propylene glycol, cyclohexane glycol
, Neopentyl glycol, butylene glycol, etc.
PET substituted with one or more other glycol components
And PEN copolyesters. The polyester of this container contains a lubricant.
It may be rare, but it is preferable to use less in terms of impact resistance
And preferably 300 ppm or less. Also polymer
Additives and UV absorbers as long as the essential properties of the
Excipients, stabilizers and pigments can be added. The C-PET container used in the present invention is an example.
For example, polyethylene with an intrinsic viscosity of 0.70 dl / g or more
92-98% by weight of terephthalate resin and polyolefin
It has a structure consisting of 2 to 8% by weight of resin,
Polyethylene terephthalate with a degree of 0.70 dl / g or more
Resin-based, substantially inorganic particles 0.1 to 10 weight
% And a wax containing 0.01 to 1.0% by weight of a wax.
Polyethylene terephthalate with a viscosity of 0.70 dl / g or more
At least a polyolefin resin based on a base resin
2 to 8% by weight, the inorganic particles and the wax are the same as the surface layer.
As described above, substantially 0.1 to 10% by weight of inorganic particles and wax
0.01 to 1.0% by weight may or may not be contained
It is a structure including a layer. Also, polyethylene terephthalate
The acetaldehyde content of the resin is 50 ppm or less.
The CT content of the ethylene terephthalate resin is 5000
It is preferably at most ppm. Furthermore, these
Sheets obtained from polyethylene terephthalate resin
Heat shrinkage of 2 to 8% as measured by JIS method K7133
Is formed by this polyester-based sheet.
It is preferable that the crystallinity of the container is 10 to 40%. The P of the C-PET container used in the present invention
The intrinsic viscosity of ET is determined by the mechanical strength and volume of the obtained sheet.
Due to sagging of the sheet in the sheet preheating process during
Inherent viscosity of 0.70 dl /
g or more, preferably 0.80 or more. In addition, intrinsic viscosity
The upper limit of the degree is not particularly limited.
Is preferably 1.5 dl / g or less. Poly
Olefin resin is used to promote the crystallization of PET
2 to 8 weight due to the impact on impact resistance of fin resin
%, Preferably 3 to 6% by weight, less than 2% by weight
The effect on crystallization acceleration and impact resistance is significantly reduced,
If the content is more than 10% by weight, an unusual odor peculiar to polyolefin resin is generated.
And cannot be used in food containers. As the polyolefin resin, polyethylene
, Polypropylene, and their various modified products.
However, polyethylene (PE) is preferred. polyethylene
High-density PE, low-density PE, etc.
Chain low density PE is preferred. AA content of the container body used in the present invention
Is 50 ppm or less, preferably 30 ppm or less,
Preferably 20 ppm or less, most preferably 15 pp
m or less, and when it is 50 ppm or more, the fragrance retention is remarkable.
Decline. The content of CT is 5000 ppm or less.
3500 ppm or less, more preferably 3000 ppm
ppm or less, and 5000 ppm or more,
Sex and taste are significantly reduced. The content of AA in the container body is 50 ppm or less.
First, a polyether with a low AA content is used.
Perform sheet molding using Tylene terephthalate resin,
A container is formed using this sheet. AA of raw resin
The content is preferably 40 ppm or less, more preferably
30 ppm or less, more preferably 20 ppm or less
Below, most preferably it is 10 ppm or less. Also see
Resin to reduce the increase in AA due to heat during production
The acid value is preferably at least 10 equivalents / ton, more preferably
Preferably 15 equivalents / ton, more preferably 20 equivalents
/ Ton, particularly preferably 25 equivalents / ton. Also,
Lower extrusion temperature during sheet production to reduce residence time
It is also important to prevent AA increase during molding
is there. The CT content of the container body is 5000 ppm
The following methods are used for polyethylene with low CT content.
A sheet is formed using lentephthalate resin and
A container is formed using the sheet. Polyethylene used
The CT content of the terephthalate resin is preferably
Is 5000 ppm or less, more preferably 4000 ppm
Or less, more preferably 3000 ppm or less. Ma
In addition, CT was generated by the polycondensation catalyst during sheet molding.
Reduce the polycondensation catalyst, deactivate the polycondensation catalyst
Resin manufactured by such a method.
preferable. Also, lower the extrusion temperature during sheet production,
By reducing the residence time, the amount of CT increase during molding can be reduced.
It is also important to prevent it. Further, a polyester used for molding a container is provided.
The heat shrinkage of the metal sheet is 2 to 8%, preferably 3 to 6%.
If less than 2%, the sheet preheating process during container molding
Sagging of the sheet at the site causes operability to deteriorate significantly
However, if it is larger than 8%, the mold rule will be poor when molding the container.
A satisfactory container shape cannot be obtained. Heat shrinkage to 2-8%
To do this, touch roll and chill during sheet production
Roll pressure, resin discharge from extruder and sheet
Adjust the heat shrinkage by adjusting the winding speed
can do. Further, a crystal such as a container used in the present invention may be used.
The degree of conversion is 10 to 40%, preferably 20 to 35%.
is there. If the crystallinity is less than 10%, the container will have sufficient heat resistance
Properties cannot be obtained, and if it exceeds 40%, it will be in an overcrystallized state.
Impact resistance is significantly reduced. At the time of molding,
It is necessary to adjust the molding conditions so that the crystallinity falls within the above range
There is. The container used in the present invention may have
Small amounts of other polymers within a range that does not impair the effects of the present invention.
Alternatively, additives may be mixed. These polymers
Or as additives, for example, other than polyamide, PE
Polyolefin, other polyester, titanium dioxide
Matting agents such as alumina, alumina oxide, phosphoric acid, phosphorous acid and
Stabilizers such as those esters, antioxidants, antibacterial agents, ultraviolet
Radiation absorbers, fluorescent brighteners, pigments, dyes, etc.
You. [0019] The processed container is filled with the contents and then used as a lid material.
More sealed. The lid is not particularly limited
Not available, but polyester, polyolefin, polyamide, etc.
Metal such as plastic sheets and films, aluminum foil
Examples include foil, paper, and laminates thereof. In this
Also biaxially stretched PET film, unstretched nylon film
Materials with low oxygen permeability, such as
No. As a sealing method, a method using heat sealing is used.
The method is preferred. To C-PET as heat seal material
Polyester heat sealant
preferable. Also, make sure the container is easy to open.
The toseal agent preferably has an easy peel property. The base resin of the polyester heat sealant
Polyvalent carb of polyester resin used as rimer
As the acid, terephthalic acid 40 mol% or more, glycol
Butanediol 80% by mole or more as a component
desirable. Terephthalic acid less than 40 mol%, pig
If it is less than 80 mol%, the melting point will decrease and letto
The tilting property deteriorates. Also, the crystallization speed decreases,
At the time of film winding, blocking occurs. The present invention
Crystalline polyester for easy peel seal material
As long as it is within the above range, other components may be copolymerized.
Can be. At this time, the polyvalent carboxylic acid component is
Talic acid, orthophthalic acid, naphthalenedicarboxylic acid,
Succinic acid, adipic acid, azelaic acid, sebacic acid, deca
Acid, dimer acid, cyclohexanedicarboxylic acid, tri
Known substances such as melitic acid can be used. Also, Geo
Ethylene glycol, propylene glyco
, 2-methyl-1,3-propanediol, pentane
Diol, 3-methylpentanediol, hexanedio
, Nonanediol, cyclohexane dimethanol,
Trimethylolpropane or the like can be used. Adjusting the heat sealing strength to an appropriate level
-To improve the peelability, the crystalline poly
Including polyolefin resin in addition to steal
it can. When blending polyolefin resin, 3
-20% by weight, preferably 8-20% by weight. the above
By containing a polyolefin resin within the range, 1
EasyP with peel strength of ~ 2kgf / 15mm
Performance can be achieved. Actually peel off by hand
In particular, excellent easy peelability, that is, good peeling
3% by weight or more of polyolefin resin
It is preferred to blend. However, if the blend amount is 20
If the amount exceeds 10% by weight, the sealing strength tends to be weak.
And the flavor is inferior.
Problems such as adsorption of content components occur. Poly to add
Olefin resins include polyethylene and polypropylene
, Polybutene, ionomer, ethylene propylene
Polymer, ethylene butene copolymer, propylene butene copolymer
Polymers and the like can be used. Polyester heat sealing agent base
Glass transition of polyester resin used as remer
The temperature is 0 ° C or lower, preferably -5 ° C or lower. Glass
If the transition temperature exceeds 0 ° C, the crystalline polyester
Crystallized polyethylene terephthalate with large volume shrinkage during crystallization
Adhesion to the rate is significantly reduced. Polyester heat sealant base
The melting point of the polyester resin used as the remer is 12
0 to 200 ° C, preferably from 120 to 180 ° C.
Good. Adhesion at retort when melting point is less than 120 ° C
Whitening or deformation of the layer causes deterioration of appearance and seal strength
Temperature greatly decreases, and when the temperature exceeds 200 ° C, the sealing temperature increases.
The C-PET softens and deforms
Appearance becomes poor. The intrinsic viscosity of crystalline polyester is
It is usually about 0.5 to 2.0 from the viewpoint of film formability.
Is preferred. The base resin of the polyester heat sealant
Polyether to polyester resin used as rimer
When glycol is copolymerized with 5 to 60% by weight, good a
Easy peeling is obtained. Polyether glycol
If it is less than 5% by weight, the adhesive strength tends to be high, and
When the content exceeds 60% by weight, the adhesiveness is deteriorated and decomposed.
Increases the amount of polyether glycol and produces odor
You. Therefore, it is inferior in flavor. Also at this time
Terglycol is preferably polytetramethylene glycol
New Easy peel sealant by using this
Good molecular weight
Jeep peelability is obtained. Further, the heat sealant has a specific surface area of 40.
0m^Two/ G or more of silica is added in an amount of 0.1 to 5% by weight.
Good flavor properties are obtained. Specific surface area is 400m^Two
When silica smaller than / g is used, the flavor is poor.
Become. In addition, if the amount added is less than 0.1% by weight,
Bar characteristics deteriorate. Adhesive if more than 5% by weight
Is reduced. Therefore, it is expected that the above conditions are satisfied.
Good. Various heat sealants may be used as necessary.
Additives can be added. For example, with a slip agent
For example, silica, talc, mica, calcium carbonate, etc.
Monoglyceride stearate and sorby as antistatic agents
And polyoxyethylene tannate. In addition, its characteristics
Polyolefin resin, polyamide
Metal, polycarbonate, etc.
You. The heat sealant is directly melt-pressed on the substrate.
It can be taken out and made into a laminate, and heat sealant
The crystalline polyester used for the film in advance
After forming the film, the above-described base is formed using another suitable known adhesive.
It can also be laminated on materials. The thickness of the heat sealant can be arbitrarily determined depending on the application.
Although it can be determined, it is usually about 3 to 50 μm.
Also, the thickness of the lid material can be arbitrarily determined according to the application.
However, it is usually about 20 to 150 μm. In the packaging method of the present invention, six months have passed since the packaging
It is necessary that the oxygen concentration in the subsequent container is 3% or less.
You. Oxygen concentration in the container 6 months after packaging is 3% or less
The new content without deterioration for a long time.
A fresh state can be maintained. 6 months after packaging
The oxygen concentration in the vessel is preferably 2.5% or less, more preferably.
Or less than 2%. The oxygen concentration in the container after 6 months from the packaging
As a method of reducing the content to 3% or less, first,
The oxygen concentration should be 3% or less. More preferably 2% or less
It is. In addition, make the container thicker,
The use of a transparent base material may be used. like this
Using oxygen absorber, etc. by taking the method
In addition, the inside of the container can be kept in a low oxygen state for a long time. The packaging method of the present invention is a heat-resistant C-PET container.
Low odor and extract of the container itself
Low effect, low oxygen permeability effect, C-PET as lid material
Use a sealant that has high adhesion to
Has the effect of low odor and low extractability of the sealant itself,
The effect of the low oxygen permeability of the base material of the lid,
Maintain the taste and aroma for a long time,
Can be cooked and cooked using oven, microwave oven, etc.
Yes, and use sealant with easy sealing properties
Can be easily opened by hand if
You. [0033] The present invention will be further described below with reference to examples and comparative examples.
However, the present invention is not limited to this.
No. The main methods for measuring physical properties are as follows. (1) Intrinsic viscosity (IV) Phenol / tetrachloroethane = 60/40 (weight
Ratio) at a temperature of 30 ° C. (2) AA content A sample obtained by crushing the bottom of a container / distilled water = 1 g / 2 ml
Put in a glass ampoule purged with nitrogen and seal the top.
Extraction treatment was performed at 60 ° C for 2 hours, and after cooling, AA
The amount is measured by high sensitivity gas chromatography and the concentration is pp
Indicated by m. (3) CT content Hexafluoroisopro
Dissolve in a mixture of panol / chloroform and add
Add form and dilute. Add methanol to this and add
The limer is precipitated and filtered. The filtrate is evaporated to dryness,
Make up to volume with methylformamide, liquid chromatograph
(HPLC)
The formed cyclic trimer was quantified. (4) Acid value (AV) Approximately 0.5 g of a sample obtained by grinding the bottom of
Dissolve in 20 ml of Cole, add chloroform and dilute
You. Using a 1 / 50N aqueous potassium hydroxide solution by titration
I asked for AV. Using phenol red as an indicator
Was. (5) Impact strength Cut the container cut out at -10 ° C into a Dupont drop weight.
Using an impact test, a 76 g weight is 75 cm high and 1
The percentage of the test number 15 when the weight is dropped from 25 cm
The number was measured. (5) Heat shrinkage It was measured according to JIS method K7133. Heating conditions are temperature
Degree 100 degreeC, time 15 minutes. (6) Oxygen concentration in the container Iijima Electric Industry Co., Ltd. Food Oxygen Analyzer (RO-
102-SDP). (7) Retortability After heat sealing the container and lid, retort treatment (boiling
(Immersed in water for 30 minutes) to evaluate the adaptability. Contents
× indicates leakage, and ○ indicates no abnormality.
And (8) Flavor properties After leaving it in a room at 40 ° C for one month, retort treatment was performed.
And then evaluate the flavor of the contents for water.
Was. Water in the container after heat treatment is smelled by 10 panelists
No, the taste is checked, and there is no paneler
◎, 1 or 2 cases ○, 3 to 5 cases △, 6
The case of more than a person was rated as ×. (9) Adhesive strength Cut out the heat-sealed part and use Toyo Baldwin
Tensile test using RTM100 manufactured by
Measure the T-peel adhesion at a pulling speed of m / min
Was. (Production of crystalline PET sheet)
The ET and PE resins are as follows. PET Tree using PET resin (RP560) manufactured by Toyobo
The fat properties are as follows: IV = 1.00 g / dl AA = 2.2 ppm CT = 3040 ppm AV = 27 equivalents / ton PE ULTSEX 3010F (low
Density PE resin). Using each of the above resins, a homemade sheet
Sheet with 0.5mm thickness and PE content of 5% by weight
Got. The properties of the obtained sheet are as follows. IV = 0.85 g / dl AA = 6.0 ppm CT = 4000 ppm AV = 28 equivalents / ton (PEN (polyethylene naphthalate)
The PEN resin used is as follows. What
The same PE resin as that described above was used. PEN Using Toyobo's PEN resin The resin properties are as follows. IV = 0.58 g / dl AA = 4.2 ppm AV = 23 equivalents / ton Using each of the above resins, a homemade sheet
Sheet with 0.5mm thickness and PE content of 5% by weight
Got. The properties of the obtained sheet are as follows. IV = 0.54 g / dl AA = 6.3 ppm AV = 25 equivalents / ton (Production of Amorphous PET Sheet)
The ET resin is as follows. The PE resin is PE
The same resin was used. Amorphous PET Uses amorphous PET resin (SI173) manufactured by Toyobo
did. The composition is terephthalic acid // ethylene glycol /
Neopentyl glycol = 100 // 70/30 mol%
Consists of The resin properties are as follows. IV = 0.72 g / dl AA = 15.3 ppm CT = 3500ppm AV = 12 equivalents / ton Using each of the above resins, a homemade sheet
Sheet with 0.5mm thickness and PE content of 5% by weight
Got. The properties of the obtained sheet are as follows. IV = 0.65 g / dl AA = 8.1 ppm CT = 4000 ppm AV = 14 equivalents / ton (Production of crystalline PET sheet with low crystallinity)
The PET resin used was the same as in Example 1. Note that
The same PE resin as that described above was used. Crystalline PET Resin properties using crystalline PET resin manufactured by Toyobo
It is as follows. IV = 1.00 g / dl AA = 2.2 ppm CT = 3040 ppm AV = 27 equivalents / ton Using each of the above resins, a homemade sheet
Sheet with 0.5mm thickness and PE content of 5% by weight
Got. The properties of the obtained sheet are as follows. IV = 0.85 g / dl AA = 6.0 ppm CT = 4000 ppm AV = 28 equivalents / ton (Production of crystalline PP sheet) Crystal used
The conductive PP resin is as follows. Crystalline PP Novatec PP E, a crystalline PP resin manufactured by Nippon Polychem
A8 was used. Homemade sheeting using the above resin
A sheet of PP resin having a thickness of 0.5 mm was obtained with a machine. (Manufacture of Container) Next, using these sheets
And filled with Sanwa Kogyo's vacuum pressure forming machine TVP-33
A tray container with a 320 cc injection capacity was obtained. In addition, sheet molding
All barrel temperature conditions are set at 290 ° C, and
All sheet preheating conditions are set to 90% heater output,
The mold temperature conditions at the time of molding are all set at 180 ° C.
The heating time was all set at 10.5 sec. However, ratio
The mold temperature conditions during container molding of Comparative Examples 2 and 3 were 23 ° C.
Was. (Manufacture of lid) Biaxial stretching P having a thickness of 50 μm
Polyester resin (terephthalic acid / iso
Phthalic acid // butanediol / polytetramethylene glycol
95 parts of coal (65/36 // 83/17 molar ratio)
Press the heat sealant which melt-mixes 5 parts of polypropylene.
Laminated to 5 μm by extrusion lamination, and lid material (a)
did. Further, 1 part of silica was added to the above heat sealant.
A lid material (b) was used. Embodiment 1 Using a crystalline PET container and lid material (a), add 200 ml of water
Then, replace the inside of the container with nitrogen, and heat it with a heat sealer.
140 ° C, pressure 2kgf / cm^TwoIn two seconds
I let you. The oxygen concentration in the container immediately after was 0.2%. Embodiment 2 In Example 1, a crystalline PET container was used instead of the crystalline PET container.
Example 1 was repeated except that a vessel was used. Embodiment 3 The procedure was performed in the same manner as in Example 1 except that the lid member (b) was used. Comparative Example 1 Amorphous PET instead of crystalline PET container in Example 1
The procedure was the same as in Example 1 except that a container was used. Comparative Example 2 High crystallinity (crystallinity 30%) in Example 1
Low crystallinity instead of PET container (crystallinity of 8
%) Same as Example 1 except that a crystalline PET container was used
I made it. Comparative Example 3 A crystalline PP container instead of a crystalline PET container in Example 1.
The procedure was the same as in Example 1 except that was used. Table 1 shows the results. [Table 1][0062] The polyester sheet molded article of the present invention is
The packaging method used shows excellent fragrance retention and taste retention
You.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Mitsuhiro Harada             5-419 Kamiaraya, Kanazawa City, Ishikawa Prefecture F term (reference) 3E067 AB01 BA07A BB22A BB25A                       BB30A BC07A CA06 CA17                       CA24 CA30 EA06 EA32 EA35                       EB27 EE48 FA01 FC01 GD02

Claims (1)

Claims 1. A method for packaging a container made of crystallized polyester using a container sealed with a lid material, wherein the oxygen concentration after 6 months has passed after packaging in the container. A food packaging method characterized by being 3% or less.