JPH01182253A - Heat-resistant polyester coated container - Google Patents

Abstract

PURPOSE:To improve peeling strength of the coating layer of a container, by thermo- fixing the container so that the crystallinity of a polyester substrate which constitutes at least the drum part of the container and the glass transition point of the polyester substrate-coating layer composite by a forced expansion and contraction vibration method are each in a specific range. CONSTITUTION:A polyester which at least constitutes the drum part of the container is molecular-oriented bi-axially so that the in plane orientation degree (l+m) becomes higher than 0.350 when it is measured by a polarized fluorescence method. Therefore, this drum part has sufficient rigidity, anti-creep property and transparency, and at the same time can inhibit the formation of spherulite at the time of thermal fixation. Also, the drum part bears at least more than 25% of the crystallinity by a density method; therefore, has thermal stability and dimensional stability especially at a high temperature. The drum part is composed of such polyester substrate and a coating layer 21 made of gas barrier resin, which exists at least one surface of the said substrate 20. When measured by a forced expansion and contraction vibration method under the condition of an expansion and contraction vibration frequency, 110Hz, and a temperature rising speed, 3 deg.C/min, the drum part has a glass transition point higher than 100 deg.C and a 180 deg. peeling strength, for a coating layer of 35g/15mm or above in width.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat-resistant polyester container, and more particularly, to a polyester container having an excellent combination of heat resistance and gas barrier properties, and particularly to a polyester container substrate. The present invention relates to a heat-resistant polyester container that has enhanced adhesion to a gas barrier coating even under thermal shock conditions.

(Prior art) Stretched bottles made of polyethylene terephthalate (PET) have advantages such as transparency, impact resistance (drop resistance), lightness, hygiene, excessive gas barrier properties such as oxygen and carbon dioxide, and pressure resistance. Excellent for use in soy sauce, sauces, dressings, cooking oil, beer, cola, carbonated drinks such as cider, fruit juice drinks, mineral water, shampoo, detergents, cosmetics,
Widely used as packaging containers for wine, mustard, aerosol products, etc.

However, since stretched polyester bottles are also made of plastic, gas permeability can be considered to be zero in completely sealed items such as glass bottles and metal cans, whereas stretched polyester bottles are free from oxygen, carbon dioxide gas, etc. However, it has a slight permeability to water, making it inferior to cans and glass bottles in terms of food filling and preservation, causing a loss of carbon dioxide in carbonated beverages, and in beer, cola, cider, etc. There is a clear shelf life limit, and fruit juice-containing beverages are also subject to shelf life limitations due to the permeation of oxygen from the outside.

To improve this drawback, US Pat. No. 4,127
, No. 633 (Adleman), No. 4,254,170 (
Roulette et al.), No. 4,370,388 (Hirata et al.) discloses that a polyester preform for stretching is coated with a vinylidene chloride resin, and this coated preform is stretch-blow molded or stretch-blow molded. It has been proposed to coat a polyester container coated with vinylidene chloride resin to produce a vinylidene chloride resin-coated polyester container.

(Problems to be Solved by the Invention) Although the vinylidene chloride resin (PVDII:) coating layer provided on the surface of the polyester (PET) substrate significantly improves gas permeability through the vessel wall, it The problem is the adhesion between the PET substrate and the PVDC coating layer, and if this adhesion is not sufficient, for example, carbon dioxide passing through the PET substrate may cause blisters at the interface between the two, or due to drop impact, thermal shock, etc. , P.E.
Peeling may occur between the T and PVDC.

As seen in the above-mentioned specification of Hirata et al., it is already known that by increasing the crystallinity of the PVDC coating layer through heat treatment, the adhesion between the two can be improved.
The degree of improvement in adhesion is still not fully satisfactory.

Therefore, the object of the present invention is to provide excellent heat resistance and gas barrier.
In particular, we have developed a heat-resistant polyester-coated container that has a combination of properties and properties, significantly improves the adhesion between the polyester container base and the gas barrier coating, and effectively prevents peeling of the two even under thermal shock conditions. It is on offer.

(Means for Solving the Problems) According to the present invention, there is provided a blow-molded container of polyester mainly composed of ethylene terephthalate units, in which at least the body of the container has an in-plane Degree of orientation (f
A polyester substrate whose molecules are biaxially oriented so that fi+m) is 0.350 or more and heat-set so that the degree of crystallinity according to the density method is 25% or more, and a gas barrier present on at least one surface of the substrate. The body has a glass transition point (Tgv) of 100°C or more as measured by a forced stretching vibration method under the conditions of a stretching vibration frequency of 110H2 and a temperature increase rate of 3°C/mln. and a coating layer of 35g/15mm width or more 180°
A heat-resistant polyester coated container characterized by having peel strength is provided.

(Function) The heat-resistant polyester coated container of the present invention is different from the prior art in that it is formed by blow-molding a polyester mainly composed of ethylene terephthalate repeating units and is provided with a gas barrier resin coating layer on one surface. The crystallinity of the polyester base and the glass transition point (Tgv) of the polyester base-coating layer composite measured by forced stretching vibration method are different from the polyester coated container.
The coating layer 18° peel strength (HL) is heat-set so that it is within a certain range.
It is characterized in that the peel strength between the two is significantly improved so that it is 35g/15av+width or more. That is,
The present invention is based on the new finding that the adhesion (peel strength) between a polyester substrate and a gas barrier resin coating layer largely depends on the glass transition point (Tgv) of this composite obtained by forced stretching vibration method. .

The attached drawing 341 shows a biaxially stretched blow container made of polyethylene terephthalate according to Example 1, which will be described later.
Relationship between glass transition point (Tgv) and 180° peel strength (P2R) measured by forced stretching vibration method for composites coated with vinylidene chloride resin under various heat setting conditions. is plotted. According to Fig. 1, as the Tgv of the composite increases, the 180° peel strength (P2R) increases monotonically and rapidly, compared to the one with a Tgv of about 88°C (immaturely fixed). The surprising fact becomes clear that the 180° peel strength (h*) increases about 10 times in the case where the Tgv has been improved to about 127°C.

In the present invention, the fact that the P2R of the complex is significantly improved by setting the Tgv of the complex to 100°C or higher is that
This was discovered as an experimental result, and its theoretical basis has not yet been clarified. however,
The present inventors presume the reason for this as follows. The glass transition point (Tgv) by the forced stretching vibration method is determined as the temperature at which the loss tangent (tan δ) reaches its maximum value.
Here, the loss tangent (tan δ) is given by the following formula: It will be done. In the composite container of the present invention, increasing the Tgv to the high temperature side means that the dynamic viscosity is low at a constant temperature below Tgv, and this contributes to improving the adhesion. Seem.

In the container of the present invention, at least the polyester constituting the body has an in-plane orientation degree (J!) measured by polarized fluorescence.
+m) is 0.350 or more, especially 0.400 or more, so that the body has sufficient rigidity, creep resistance, and transparency, and This is important from the standpoint of suppressing the formation of spherulites during fixation.

The density of polyester is generally used as a measure to express the molecular orientation of polyester, but since the density of polyester varies greatly depending not only on the degree of molecular orientation but also on the degree of heat fixation (i.e. crystallinity), the present invention In this case, it cannot be used as a measure of molecular orientation.

On the other hand, polarized fluorescence spectroscopy uses the optical anisotropy of fluorescent molecules adsorbed on molecularly oriented polymers to quantitatively measure the molecular orientation of polymers. The degree of molecular orientation can be determined without being affected by heat fixation. The degree of two-dimensional orientation within the container wall determined by this polarized fluorescence method is expressed by the following formula.

......(2) In the above formula, ■1. (ω) represents the polarization component intensity of fluorescent light emitted from the sample thermoplastic resin system, 〃 indicates that the vibration direction of the incident polarized light and the photometric polarization direction are parallel, and ω represents the sample relative to the vibration direction of the polarized light. is the rotation angle of , is the maximum excitation probability when the vibration direction of the excited fluorescence is parallel to the sample molecular axis, and φ is the molecular fluorescence yield. 2 is the ratio of molecules oriented in one arbitrary direction within the wall surface of the final molded container, m
represents the ratio of molecules oriented in the direction perpendicular to I, and n represents the ratio of in-plane non-orientation, which is Ji + m + n-total 1.

It can be expressed quantitatively.

Thus, changing ω (0', 45@, 90@
), measure the polarization component intensity I, (ω) for this ω,
The values of 21m and n can be obtained as solutions to these three simultaneous equations.

In addition, the polyester constituting at least the body has a crystallinity of at least 25%, particularly 27 to 4, as determined by the density method.
Being in the range of 8% is important in terms of thermal stability, especially dimensional stability at high temperatures.

The degree of crystallinity by the density method is determined by the following method. 2
A strip of the sample to be measured (approximately 2 +amx
2 am) is allowed to settle, and the measured specific gravity; d is obtained from the position where the sample is at rest.

Then, from the obtained value of each measured specific gravity; d, the following formula, (1/d) = ((1-x)/da) + (x/dc
) ・” Calculate each crystallinity; X according to (3). Here, da is the crystallinity, and the specific gravity value when
da=1.335), and dc is the degree of crystallinity; the specific gravity value when X is 100% (dc=1.455
).

In addition, in the case of coated bottles, the in-plane orientation by polarized fluorescence method and the crystallinity by density method were measured by gently peeling off the gas barrier resin coating layer and measuring the polyester base material alone. .

It can be safely assumed that the forced stretching vibration method glass transition point (Tgv) of the composite is almost the same as the Tgv' of the polyester base. This Tgv is related to both the degree of in-plane orientation and the degree of crystallinity of the polyester, but according to the present invention, Tgv
so that the gv is 100°C or higher, especially 105°C or higher,
Combining in-plane orientation and crystallinity.

(Preferred Embodiment of the Invention) 2. Structure of Stretched Polyester Container FIGS. 2 (side view) and 3 (
In FIG. 4 (bottom view) and FIG. 4 (sectional view), this biaxially stretched polyester container 1 has an unstretched nozzle part (neck part) 2,
truncated conical shoulder 3, cylindrical body 4 and closed bottom 5
It consists of

The main part of the body 4 has a short pillar-shaped protrusion 7 with a relatively large diameter and short circumference, and a short panel-shaped recess 6 with a relatively small diameter and long circumference. A large number of them are provided alternately in the circumferential direction via the connecting parts 8. The pillar-shaped protrusions 7 extend in the axial direction (height direction) of the container, and therefore the panel-shaped recess 6 has a rectangular shape with rounded long corners in the axial direction of the container partitioned by the pillar-shaped protrusions 7. are doing.

As understood from the cross-sectional view of FIG. 4, the panel-shaped recess 6
can expand (protrude) radially outward as the internal pressure increases and contract inward (concave) as the internal pressure decreases, thereby having the effect of alleviating changes in internal pressure.

In the specific example shown in the drawings, a bulging ring portion 9 with a relatively large diameter and an adjacent groove-like ring portion 10 with a relatively small diameter are provided above the panel-shaped recess installation portion. This allows for slight deformation in the axial direction of the container. Further, there is a star-shaped inward concave portion 11 in the center of the bottom portion 5, which prevents the bottom portion 5 from buckling outward due to pressure or thermal deformation.

In FIG. 5, which shows an enlarged cross-sectional structure of the coated container, this container is made up of a polyester base 20 and a gas barrier resin coating layer 21 provided on at least one surface thereof.

1) Solid container temperature method In the present invention, the thermoplastic polyester is a thermoplastic polyester mainly composed of ethylene terephthalate units, such as PET, and the glycol component contains a small amount of other glycols such as hexahydroxylylene glycol. A so-called modified PUT containing a small amount of another dibasic acid component such as isophthalic acid or hexahydroterephthalic acid as a dibasic acid component is used. These polyesters can be used alone or in the form of blends with other resins such as nylons, polycarbonates or polyarylates.

The intrinsic viscosity of the thermoplastic polyester used is 0.67 dl
/g or more and the content of diethylene glycol units is preferably within the range of 2.0% by weight or less.

The bottomed preform used in stretch blow molding is manufactured by any method known per se, such as injection molding, vibrator extrusion, and the like. In the former method, molten polyester is injected to produce a bottomed preform in an amorphous state with a mouth and neck corresponding to the final container. The latter method is
The extruded amorphous vibrator is cut, one end is compression molded to form a mouth and neck part, and the other end is closed to form a bottomed preform. In either case, engagement with the lid at high temperatures,
In order to maintain a good sealing state, only the portion that will become the mouth and neck of the container can be thermally crystallized in advance. Of course, this thermal crystallization may be performed at any subsequent step.

The temperature range is 85 to 115℃ by using the heat given to the preform of the prepared multilayer preform injection machine, that is, the residual heat.
In the case of a cold parison, the stretching temperature is adjusted to a stretching temperature of 85 to 115°C, or reheated and preheated to a stretching temperature range of 85 to 115°C. When biaxially stretching with a blow mold, the blow mold is
Heat treatment (heat setting) is started at the same time as the PET wall of the stretch-blown preform is brought into contact with the inner surface of the mold by heating the mold at ~230° C., preferably from 120° C. to 210° C. After a predetermined heat treatment time, the blowing fluid is switched to the internal cooling fluid to start cooling from the inside. The heat treatment time varies depending on the thickness and temperature of the blow molded product, but P
ET to the aforementioned crystallinity, generally on the order of 1.5 to 30 seconds, particularly 2 to 20 seconds. On the other hand, the cooling time also varies depending on the heat treatment temperature and the type of cooling fluid, but is generally 1 to 30 seconds, especially 2 to 20 seconds.
It is on the order of seconds.

As the high-temperature, high-pressure blowing air, air heated to a higher temperature than the preform temperature is used, and in terms of high-speed stretching and heat-setting efficiency, the temperature is 100 to 150 °C, especially 110 to 1
Advantageously, air at a temperature of 40° C. is used. Also, the pressure is 10 to 50 g/c112 (gauge), especially 25
A range of 30 to 30 Kg/cn2 (gauge) is desirable in terms of high-speed stretchability and heat-setting efficiency.

As the cooling fluid, various cooled gases, such as -4
In addition to nitrogen, air, carbon dioxide, etc. at 0°C to +10°C, chemically inert liquefied gases such as liquefied nitrogen gas, liquefied carbon dioxide, liquefied trichlorofluoromethane gas, liquefied dichlorodifluoromethane gas, and other liquefied aliphatic gases. Hydrocarbon gas etc. are also used. This cooling fluid may also contain a liquid mist having a large heat of vaporization, such as water. By using the cooling fluids described above, significantly greater cooling rates can be obtained. Of course, as cooling air, room temperature air can also be supplied at a pressure of 10 to 50 Kg/cm' (gauge), particularly 20 to 45 Kg/cm' (gauge).

The stretching ratio is 1.2 to 3.0 times in the axial direction, especially 1.5 to 2.5 times, and 2 to 5 times in the circumferential direction.
In particular, it is preferable to set it to 2.5 to 4.5 times.

In addition, two molds are used for blowing, and after performing heat treatment (heat setting) in the first mold within the above-mentioned temperature and time range, the sample is placed in the second mold for cooling.
It is also possible to adopt a method in which the sample is cooled at the same time as it is poured into a mold and blown again.

The biaxially stretched heat-set polyester container used in the present invention has a body of 0. lO~0.95mI! ! , especially 0.1
Preferably, it has a thickness in the range of 5 to 0.80 a+m.

Further, the dimensions of the panel-shaped recess vary depending on the size of the container, but it is generally desirable that the circumferential dimension is in the range of 10 to 50 mm and the axial direction (height direction) dimension is in the range of 40 to 160 mm. Further, it is preferable that the step, that is, the difference in diameter, between the large-diameter pillar-shaped convex portion and the small-diameter panel-shaped concave portion is within a range of 1 to 8 mm.

Gas barrier resin coating Gas barrier resin coatings include resins that have excellent gas barrier properties and can be applied, such as vinylidene chloride resin, ethylene-vinyl alcohol copolymer, high nitrile resin, xylylene group-containing polyamide resin, and high barrier properties. Polyester etc. can be used.

The vinylidene chloride copolymer preferably used in the present invention contains vinylidene chloride in an amount of 99 to 35% by weight, particularly 96 to 50% by weight. Any comonomer other than vinylidene chloride may be used as long as it is an ethylenically unsaturated monomer that can be copolymerized with vinylidene chloride, but generally this comonomer is an acrylic or methacrylic monomer. It should contain the body as an essential component.

As the acrylic or methacrylic monomers mentioned above,
Acrylic acid, methacrylic acid or their conductors are used, and preferred examples include the following formula R1 CH2C where R2 represents a hydrogen atom, a halogen atom, an acid or methyl group, and X represents a nitrile group. (-CaiN) or the formula (wherein Y is an amino group, a hydroxyl group, an alkyloxy group, a cycloalkyloxy group, an aminoalkyloxy group, a hydroxyalkyloxy group, an alkoxyalkyloxy group, a haloalkyloxy group, a glycidyl group, an aryloxy group) group, representing an aralkyloxy group).

monomers, especially acrylic acid, acrylonitrile, acrylamide, methyl acrylate, ethyl acrylate, α-
Methyl chloroacrylate, propyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, cyclohexyl acrylate, glycidyl acrylate,
2-hydroxyethyl acrylate, monoglyceride acrylate, phenyl acrylate, methacrylic acid, methacrylonitrile, methacrylamide, methyl methacrylate, amyl methacrylate, glycidyl methacrylate, monoglyceride methacrylate, 2-hydroxypropyl methacrylate, Mention may be made of β-methoxyethyl methacrylate, β-aminoethyl methacrylate, and γ-N, N-diethylaminoprobyl methacrylate.

These acrylic or methacrylic monomers can be used alone or in combination with Zfl or more.6 Acrylic or methacrylic monomers particularly suitable for the purpose of the present invention are:
(1) Nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, (i++)
Ester monomers such as methyl acrylate, ethyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl acrylate, glycidyl methacrylate, acrylic acid monoglyceride, methacrylic acid sonoglyceride, methoxyethyl acrylate, methoxyethylmethyl methacrylate, etc. mer and (lli) above (1)
and (11).

Ethylenically unsaturated monomers other than vinylidene chloride and acrylic to methacrylic monomers include vinyl aromatic monomers such as styrene and vinyltoluene; vinyl esters such as vinyl acetate and vinyl propionate; butadiene, Diolefins such as isoprene; methyl vinyl ether,
Glycidyl acrylic ether, vinyl chloride, ethylene trichloride, ethylene tetrachloride, vinyl fluoride, vinylidene fluoride, ethylene trifluoride, ethylene tetrafluoride, maleic anhydride, fumaric acid, vinyl succinimide, vinyl pyrrolidone, etc. These monomers can be used alone or in combination of two or more.

Examples of suitable copolymers include, but are not limited to:

Vinylidene chloride/acrylonitrile copolymer, vinylidene chloride/acrylonitrile/methacrylomutrile copolymer, vinylidene chloride/methacryliconitrile copolymer, vinylidene chloride/acrylonitrile/glycidyl acrylate copolymer, vinylidene chloride/acrylonitrile/glycidyl methacrylate Copolymer, vinylidene chloride/acrylonitrile/monoglyceride acrylate copolymer, vinylidene chloride/ethyl acrylate/glycidyl acrylate copolymer, vinylidene chloride/methyl methacrylate/styrene copolymer, vinylidene chloride/acrylonitrile/styrene Copolymer, vinylidene chloride/acrylonitrile/ethylene trichloride copolymer, vinylidene chloride/acrylonitrile/vinyl chloride copolymer, vinylidene chloride/acrylonitrile/methacrylic acid monoglyceride/ethylene trichloride copolymer, vinylidene chloride/methoxyethylmethylmeth Acrylate/methyl methacrylate/ethylene trichloride copolymer.

The vinylidene chloride copolymer used in the present invention is generally produced by emulsifying or suspending the constituent monomers in an aqueous medium by the action of an emulsifier and a dispersant, and carrying out emulsion polymerization or suspension in the presence of a radical initiator. It can be easily obtained by polymerization. As the radical initiator, peroxides, azo compounds, or redox catalysts that are known per se are used.

The vinylidene chloride copolymer used in the present invention generally only needs to have a molecular weight sufficient to form a film.

The dispersed particle size of the vinylidene chloride copolymer in the latex is also related to thick coating properties and viscosity stability.

Generally, the average particle size is preferably in the range of 0.09 to 0.20 μm, particularly 0.10 to 0.17 μm.

The aqueous latex of the vinylidene chloride copolymer used in the present invention may optionally contain water-soluble synthetic polymers, natural polymers, or semi-synthetic polymers containing hydroxyl groups, such as maltose, lactose, sucrose, saccharose, cellobiose, and trehalose. Water-soluble trisaccharides such as amylose, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, propionitrile cellulose, benzylcellulose, chitin, chitin acetyl derivatives, hyaluronic acid, chondroitin hexasulfate, keratan sulfate, heparin, etc. Polysaccharides; water-soluble synthetic polymers such as polyvinyl alcohol, partially saponified polyvinyl acetate, polyvinyl alcohol with a degree of formalization of 20% or less, polyvinyl methyl ether, polyvinylethyl ether, etc. can be contained.

This aqueous latex is preferably used so that the solid content of PVDC is 30 to 65% by weight, particularly 35 to 60% by weight, and can be applied by spray coating, brush coating, electrostatic coating, etc.
The polyester container is coated by means such as cast coating, electrophoretic coating, dip coating, roller coating, fill coating, spin cording, and combinations thereof. Although generally not necessary, the polyester container may be subjected to pretreatments such as corona treatment, ozone treatment, flame treatment, etc., if desired. The thickness of the coating layer is generally 2.0 to 500 μm, especially 2.0 μm.
A range of 450 μm to 450 μm is suitable. The formed coating film shows sufficient adhesion by drying alone, but if desired, it may be heat treated at 40 to 150°C for 2 seconds to 100 minutes to increase the crystallinity of the PVDC layer to 0.5 or more. Crystallization may be carried out as follows.

(Effects) According to the present invention, it has a combination of excellent heat resistance and gas barrier properties, and in particular, it has a combination of excellent heat resistance and gas barrier properties.
A heat-resistant polyester-coated container was provided in which the adhesive strength with the polyester coating was significantly improved, and peeling between the two was effectively prevented even under thermal shock conditions.

The stretched heat-set polyester coated container of the present invention is useful as a sealed storage container for hot filling the contents at a temperature of 70 to 98°C, or for heat sterilizing the contents at a temperature of 70 to 95°C after filling. be.

(Example) The present invention will be explained in more detail in the following example. In addition, each measurement method followed the description below: 1) Dynamic viscoelasticity measurement (E' and tan δ): The body of the coated bottle (panel-shaped recess) was measured in the axial direction (longitudinal direction) of the bottle.
It was cut to a width of 6.0±0.1 ff1m. Then, the sample was transferred to Orientic Co., Ltd.'s RheoVipron,
DDV-III-E A-type forced stretching vibration method dynamic viscoelasticity measuring device was set so that the initial length was 10.0 m+a. After that, the measurement frequency (ω) was changed to 110Hz.
The temperature was raised from room temperature at a heating rate of 3°C/lll1n, and the dynamic Young's modulus (E
') and loss tangent (tanδ) were read.

11) Crystallinity (Ca) of coating film: Measured according to the method described on page 679 of Emulsion Latex Handbook (Emulsion Latex Handbook Edited by Kinen, Taiseisha). That is, the side wall of the painted bottle was cut out, and the coated surface was measured by the total reflection method using an A-3 infrared spectrophotometer (manufactured by JASCO Corporation) to obtain an absorption spectrum. And absorption band specific to vinylidene chloride, 7
43 cm-', 875 cm-', 1046 cm-'
, 1071 am-', 10 indicates crystallization.
The crystallinity was evaluated using the absorbance ratio of 46 cm'' and 1071 am-' (7). Here, the increase in the absorbance ratio described above indicates that crystallization is progressing in the internal structure of polyvinylidene chloride from X-ray diffraction. An example of measuring an infrared absorption spectrum and a method of measuring absorbance are shown in FIG. In the figure, A indicates the innermost surface of the coating, and B indicates the spectrum at the interface with the base material. Moreover, these average values are shown in the Examples.

In addition, FIG. 346 shows a polyethylene film coated with vinylidene chloride latex.

720 cm-', 1350 cm-', 1425 cm-
', 2900 cm-' is the characteristic absorption band of polyethylene.

:11) Oxygen gas permeability of container: After replacing the inside of the container to be measured with nitrogen gas in a vacuum and sealing the mouth of the container with a rubber stopper or other material, the temperature and humidity conditions were maintained as described in each example. Each was stored for a predetermined period in a constant temperature and humidity chamber (conditions A and B).

Thereafter, the concentration of oxygen that permeated into each container was measured using a gas chromatograph, and the oxygen gas permeability (QO2, unit: cc/ffl"-day-at) of the container was determined according to the following formula.
m) was calculated: QO2 = [mxct/100]/
1X Op op; oxygen gas partial pressure (= 0.
209) (atm), A; effective surface area of the container (I1
1').

Oxygen gas permeability, Q02, is 1 for one type of container.
Five samples were measured for each condition, and the arithmetic average value was used as data.

lv) Out of the sample containers (10 in total) in which the oxygen gas permeability described in Beer (Peel Strength (PAR) '111) was measured, 5 samples measured under condition A were extracted, and the side wall of the container was After sampling the upper part, center part, and lower part of the container in a strip shape with a width of 20 mm in the circumferential direction of the container, the interface between the coating layer and the base material (main body) was sampled with a knife.
One end of it was partially peeled off beforehand. Then, after adhering cellophane tape in the longitudinal direction of the peeled surface of the base material (main body),
It was cut into a rectangular shape with a width of 511IIn.

After leaving the above sample in a constant temperature and humidity chamber maintained at 25°C and 60% RH for 7 days, the peeled portion of the coating layer of the sample was placed on the chuck of a tensile tester under the conditions of 25°C and 60% RH. 100mm/mi after attaching the sellotape.
A 180 degree peel test was conducted at a pulling speed of n, and the beer (peel) strength was recorded on a recorder.

The beer strength in each example represents the arithmetic average value of the above-mentioned 15-point measurement results.

■) Heat-resistant temperature of the container (Tor): Fill the sample container (in this case, a bottle) to be measured with tap water at a temperature of 20°C to the full volume, and then mI) was measured beforehand.

Then, fill the bottle with hot water ranging from 50°C to 90°C (temperature is at 5°C intervals, 10 levels in total), cap it and hold it for 5 minutes, and then the contents (tap water) will be at room temperature. The mixture was cooled with water until the temperature returned to 20°C.

Then, after removing the contents from the sample, 2
The sample was refilled with tap water at 0° C. to the full volume, and the volume (vl, unit: mp) of the dripping was measured.

The thermal deformation rate of the container, S (unit: %), can be calculated using the following formula: S=100X (V, /V.-1) I followed the instructions.

Then, the temperature of the filled hot water and the thermal deformation rate (S) are plotted, and the temperature at which the thermal deformation rate reaches the upper 2°0% is determined by interpolation from the graph, and the heat resistant temperature (Tor) is calculated. did.

Example 1 Using an FS-17ON injection molding machine manufactured by Kubata Jushi Kogyo Co., Ltd., 30% of phenol and tetrachloroethane were mixed in a 60:40 mixed solvent using an Ubbelohde viscometer.
The intrinsic viscosity (IV) when measured at a temperature of °C is 0.7
7 d/i/g+7) Polyethylene terephthalate (P
ET) and weighs 60.3g.

Preform (preformed product) with an average wall thickness of 3.85 mm
I got it. Then, the preform was transferred to Toyo Food Machinery Co., Ltd. (
The inner diameter of the mouth part was thermally crystallized using OBM-1 type biaxial stretch blow molding machine manufactured by Co., Ltd., and the internal diameter of the droplet was 22 mm, and the internal volume of the dripping was 1547 mJ! molded into a bottle. The shape of each bottle is as shown in Figures 2 to 4, with a pillar-shaped protrusion and a panel-shaped concave part on the body, and a star-shaped concave part on the bottom. Met.

In addition, the bottle molding conditions are that the preform temperature is 100
After heating at ℃ for 20 seconds, the inner surface of the cavity was longitudinally stretched with a stretch rod in a blowing mold heated to the temperature shown in the mold temperature column in Table 1, until the temperature reached approximately 1.
Transverse stretching (blowing) was carried out at a pressure of 30g/cm'' with hot air at 00°C, and at the same time as biaxial stretching, heat setting was performed for the time shown in the heat treatment time column in Table 1, and blowing fluid was applied. Switch to internal cooling fluid (air conditioned to +5°C) and again for 3 and 12 seconds (Table 1)
After applying fluid pressure (30 g/cm"), it was immediately taken out and molded by cooling. The stretching ratio of each bottle was 2.2 times in the longitudinal (axial) direction and 2.2 times in the transverse (circumferential) direction. 3.3 times larger, and the total average wall thickness of the entire bottle excluding the mouth is approximately 0.
53 to 0.54 mm (including the coating layer), and the surface area of the entire bottle excluding the mouth (nozzle) was approximately 850 CIl12.

The outer surfaces of the three types of PET bottles obtained in this way were sprayed with 92Ii amount of vinylidene chloride.
, a polyvinylidene chloride copolymer (PVDC) having a composition ratio of 8% by weight of methyl acrylate was used as a dispersion medium, and the average particle size of the colloid was about 0.12 μ m %p) 1 to 2.4
, the solid content concentration is 48.9% by weight, and the specific gravity of the latex at 20°C is 1.25. At 20°C, using a Brookfield viscometer, the rotation speed of No. 10-tar is 12 revolutions/min (rpm). A PVDC-based aqueous latex with a latex viscosity of 10.8 cps was applied. After drying at 60° C. for 5 minutes using an explosion-proof hot air circulation oven, aging was performed in a constant temperature bath at 40° C. for 5 days. Film thickness (PVOC thickness) of the polyvinylidene chloride copolymer coated on each bottle
are also shown in Table 1.

PET bottles coated with the three types of PVDC thus obtained (marked B in Table 1).

Bottles D and F), and the PVDC bottles for comparison.
For three types of PET bottles (bottles marked A, C, and E in Table 1) that are not coated with The results of the degree of crystallinity, the degree of crystallinity of the PVDC film, and the dynamic viscoelasticity are shown in the second method. In addition, the oxygen gas permeability, heat resistance temperature, and beer (peeling II) strength between the PVDC coating film and the PET base material in the coated bottle were also measured for each bottle. The results are shown in Table 3. Also, 3 f
FIG. 7 shows an example of dynamic viscoelasticity measurement for coated bottles of the ji class. Further, the temperature at which the loss tangent (tan δ) obtained by the dynamic viscoelasticity measurement shows the maximum value, that is, the second
The relationship between the glass transition point (Tgv) shown in the table and the beer strength (P 2R) shown in Table 3 is shown in FIG.

[Brief explanation of the drawing]

Figure 1 shows the transition point (Tg) of glass measured by the forced stretching vibration method.
Fig. 2 is a side view showing an example of the container of the present invention, and Fig. 3 is a side view of an example of the container of the present invention. FIG. 4 is a cross-sectional view of an example of the container of the present invention; FIG. 5 is an enlarged view of the cross-sectional structure of the coated container; FIG. 6 is an infrared absorption spectrum. Fig. 7 shows an example of measuring dynamic viscoelasticity of a coated bottle. DESCRIPTION OF SYMBOLS 1... Polyester container, 2... Unstretched nozzle part, 3... Shoulder part, 6... Panel-shaped recessed part, 20... Polyester base, 21... Gas barrier resin coating layer . Figure 1 Tcy ('C) Figure 3 Figure 4

Claims (2)

[Claims] (1) A blow-molded container of polyester mainly composed of ethylene terephthalate units, in which at least the body of the container has an in-plane orientation degree (l+m) of 0 as measured by polarized fluorescence.
．． A polyester substrate with biaxial molecular orientation of 350 or more and heat-set so as to have a crystallinity of 25% or more as measured by the density method, and a gas barrier resin coating layer present on at least one surface of the substrate. The body has a stretching vibration frequency of 110Hz and a vibration frequency of 3°C/mi.
100 as measured by the forced stretching vibration method under the condition of a heating rate of n.
It has a glass transition point (Tg) of 35g/15°C or higher and
A heat-resistant polyester coated container characterized by having a coating layer with a width of mm or more and a 180° peel strength. (2) The container according to item 1, wherein the gas barrier resin coating layer is a vinylidene chloride resin coating layer having a crystallinity of 0.5 or more as measured by infrared absorption spectroscopy.