JPS63191737A - Heat-resistant deformable gas barrier biaxial oriented polyester vessel - Google Patents

Abstract

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

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a heat-deformable gas barrier biaxially oriented preester container, and more specifically, the present invention relates to a heat-deformable gas barrier biaxially oriented preester container, and more specifically, during hot filling with contents or during the subsequent cooling process. The present invention relates to a gas barrier biaxially oriented polyester container in which asymmetric deformation of the container body is prevented and the appearance characteristics of the container can always be maintained in good condition.

(Prior art) Stretched polyurethane made of polyethylene terephthalate (PIIVR) has transparency, impact resistance (drop resistance), lightness, hygiene, appropriate gas barrier properties such as oxygen and carbon dioxide gas, pressure resistance, etc. Widely used as packaging containers for soy sauce, sauces, dressings, edible oils, carbonated drinks such as beer, cola, and cider, fruit juice drinks, mineral water, shampoos, detergents, cosmetics, wine, currants, aerosol products, etc. It is used.

However, since stretched polyester is made of plastic, it can be assumed that gas permeability is equal to zero in completely sealed items such as glass bottles and metal cans, whereas stretched polyester is made of plastic. It has a slight permeability to carbon dioxide gas, etc., and is inferior to cans and glass bottles in terms of food filling and preservation, and causes a loss of carbon dioxide gas in carbonated beverages, resulting in beer, cola, and cider. Beverages containing fruit juice have a clear shelf life limit, and fruit juice beverages are also subject to a shelf life limit due to the permeation of oxygen from the outside.

In order to improve this drawback, it has already been proposed that the container has a multilayer structure consisting of inner and outer layers of polyester and an intermediate layer of sparse resin such as ethylene vinyl alcohol copolymer or metaxylylene group-containing polyamide.

In addition, stretched polyester bottles are significantly superior to other glass bottles in terms of transparency, smoothness, and pressure resistance for gas-filled beverages, but the stretching and forming temperature is relatively low (80 to 110 degrees Celsius). ℃) and has non-stretched parts or low-stretched parts, so it has no heat resistance, so when hot cooking, the filling temperature must be 65°C or lower to be used for practical purposes, but it loses its shape retention. There is a drawback.

To eliminate this drawback, it has already been proposed, Ep4
It is already known to heat-set the non-stretched parts (for example, the neck and neck) and the stretched parts (for example, the body) of polyester bottles.

(Problems to be Solved by the Invention) Heat-setting of biaxially oriented polyester has the effect of preventing thermal deformation at temperatures up to about 65°C in the case of containers with smooth walls. vinegar.

However, in the production of bottled products by hot filling into biaxially oriented polyester containers, there is a fairly large volume change between the volume of the contents when heated and the volume when cooled. This creates a significant pressure difference between the inside and outside of the container.

In order to prevent this, a pillar-shaped protrusion with a relatively large diameter and a small circumference and a panel-shaped recess with a relatively small diameter and a large circumference are formed in the circumferential direction on the container body. These panel-like recesses are arranged alternately and have the function of being able to expand and contract in the radial direction of the body in response to changes in pressure within the container.

However, when heat setting is performed on a stretched polyester container equipped with this function, heat setting is not performed uniformly in these uneven parts, and internal distortion remains during molding and heat treatment. When hot filling the contents, the panel-shaped recess described above undergoes asymmetric deformation (-th order asymmetric deformation), and when cooling is performed after sealing, the expansion and contraction function of this panel-shaped recess does not function normally. The disadvantage is that the container after cooling becomes even more ugly and undergoes asymmetric deformation (secondary asymmetric deformation). Such drawbacks also occur when the tettle is heated and sterilized after being filled with the contents.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of conventional stretched polyester containers, and to provide a multilayer stretch-molded container including a layer made of a thermoplastic polyester such as polyethylene terephthalate and a layer made of a gas barrier resin. To provide a heat deformation-resistant gas barrier biaxially oriented polyester container that effectively prevents asymmetric deformation of the container wall during hot filling of contents or the subsequent cooling stage, and as a result maintains excellent appearance characteristics. .

(Means for Solving the Problems) According to the present invention, a preform consisting of inner and outer layers made of polyester mainly composed of ethylene terephthalate units and at least one intermediate layer made of a gas barrier resin is biaxially stretched. The container is manufactured by blow molding, and the body of the container includes pillar-shaped protrusions with relatively large diameters and small circumferential lengths arranged alternately in the circumferential direction, and pillar-shaped protrusions with relatively small diameters arranged alternately in the circumferential direction. and four panel-like parts with a large circumference, and the panel-like recess has a function of expanding and contracting in the radial direction of the body according to pressure changes within the container, comprising: an inner layer of the nine-wall part; The outer layer has biaxial molecular orientation such that the degree of in-plane orientation (z+m) measured by polarized light fluorescence is 0.350 or more, and the outer layer of the tunnel part has a crystallinity of 3096 by the density method.
There is provided a heat-deformable gas barrier biaxially oriented polyester container which is characterized in that it is heat-set so that the crystallinity of the inner layer is also 2% or more higher.

(Function) Fig. 1 (side view) and Fig. 2 (side view) showing an example of the container of the present invention.
In FIG. 3 (bottom view) and FIG.
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. Connecting portions 8f: A large number of connecting portions are provided alternately in the circumferential direction. The pillar-shaped protrusions 7 extend in the axial direction (height direction) of the container, and therefore the tunnel-shaped recesses 6 have a rectangular shape with rounded long corners in the container axial direction separated by the pillar-shaped protrusions 7. are doing.

As can be understood from the cross-sectional view of FIG. 3, the tunnel-like recess 6 can expand (protrude) radially outward as the internal pressure increases, and contract inward (concave) as the internal pressure decreases. This has the effect of alleviating changes in internal pressure.

In the specific example shown in the drawings, a bulge/gang portion 9 with a relatively large diameter and a groove-shaped ring portion 10 with a relatively small diameter adjacent thereto are provided above the portion where the groove-shaped recess is installed. is provided to allow slight deformation in the axial direction of the container. In addition, there is a star-shaped inward concave portion 11 in the center of the bottom portion 5, which prevents the bottom portion 5 from packing outward due to pressure or thermal deformation.

In FIG. 4, which shows an enlarged cross-sectional structure of this container, the multilayer blow container 1 has a polyester inner layer 20, a polyester outer layer 30, and a gas barrier located in between.
It consists of a synthetic resin intermediate layer 40. A resin adhesive 50, 50' may be interposed between the intermediate layer 40 and the inner and outer layers 20, 30.

The gas barrier biaxially oriented polyester container of the present invention has the above-mentioned body wall shape and structure and has a multilayer cross-sectional structure, and the inner layer and outer layer of the nine-walled portion are measured by polarized fluorescence method. The molecules are biaxially oriented so that the degree of in-plane orientation (j+m) is 0.350 or more, and the outer layer of the panel has a crystallinity of 30% or more by the density method, and the crystallinity of the inner layer is 30% or more. A notable feature is that it is heat-set to a value 2% or more higher than The advantageous feature is that secondary asymmetric deformation of the container body is prevented and the appearance characteristics of the container are always maintained in good condition.

That is, the body of the ester container is biaxially stretched blow molded,
That is, the molecules are oriented in biaxial directions by tensile stretching in the axial direction and expansion stretching in the circumferential direction, but in the multilayer polyester container of the present invention, the tunnel portion has sufficient rigidity and creep resistance, and is further transparent. to have a sexual nature;
In order to suppress the formation of spherulites during heat fixation, it is necessary that the molecules be oriented, and for this purpose, the degree of in-plane orientation (t4-rn) measured by polarized fluorescence spectroscopy is Both the inner polyester layer and the outer polyester layer must have a value of 0.350 or higher.

The density of polyester is generally used as a measure to express the molecular orientation of 41J ester, 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), In the case of invention, 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.

It can be expressed quantitatively.

In this way, we change ω (0°, 45°, 90°), measure the polarization component intensity ■, (ω) for this ω, and
The values of t, m, and n can be obtained as solutions to the two simultaneous equations.

In the container of the present invention, the outer layer polyester resin of the quenelle portion is heat-set so as to have a crystallinity of 30% or more and a value higher than that of the inner layer polyester resin by 2 cm or more, especially 3 cm or more. A notable feature is that That is, when the outer layer polyester of a multilayer stretched polyester is selectively and highly crystallized, the hoop effect of this crystallized polyester outer layer causes non-uniformity in a part of the panel when hot filling is performed. This is based on the new finding that primary thermal deformation (asymmetric deformation) and secondary asymmetric deformation during subsequent cooling are effectively prevented. That is, in the present invention, the entire je IJ ester is not uniformly heat-set, but the polyester layer located on the outside of the container is heat-set through the gas barrier layer so that it is intensively crystallized. be. In addition, since the outer surface is highly crystallized, it has a hard structure that is difficult to scratch, and the inner surface has a lower degree of crystallinity, resulting in a strong structure that is resistant to drop impacts. There is also an advantage. This heat fixation is only possible through the combination of the multilayer structure in which the sparring resin intermediate layer is present and the heat fixation operation described below.

That is, the container of the present invention uses a mold having a cavity shape corresponding to the container shape described above, and has inner and outer layers made of polyester mainly composed of ethylene terephthalate units and at least one intermediate layer made of f-sparring resin. A multilayer preformed product containing a layer is preheated or controlled to an appropriate stretching temperature of 85 to 115°C, and the preformed product is subjected to biaxial stretch blow molding in a mold maintained in a heat-setting temperature range. At the same time, the blow molded body is heat-treated, and then the pressurized fluid for blow molding is switched to the internal cooling fluid, and the blow molded body is taken out from the mold while the blow molded body is in contact with the surface of the mold cavity. It is manufactured by cooling to a temperature at which it does not lose its shape, and then removing the molded product from the mold.

In FIG. 5 for explaining the state during this heat treatment,
In the post-heat treatment cooling stage, the polyester outer layer 30 is heated by contacting the mold 60 heated to the heat setting temperature, while the polyester inner layer 20 is in a cooled state by contacting the cooling fluid 70. In the present invention, since the gas barrier resin intermediate layer 40 acts as a heat transfer barrier layer, ? While the polyester inner layer 20 is rapidly cooled to a temperature that is generally 60° C. or lower, at which it can be taken out of the mold without losing its shape,? The temperature of the realester outer layer 30 and the mold 60 in contact with it does not drop much due to this inner layer cooling operation, which provides an advantage in that the outer layer is effectively heat-set.

Table 1 below shows the thermal conductivity of the resins of the vertebrae.

Table 1 Resin Vinylidene chloride resin 2.50-2,65EVO
H2,00~2.55 Stretched PET 6.40~7.80 Unstretched PET
4.90-5,55 These results show that gas barrier resins such as ethylene-vinyl alcohol copolymer (EVOH) have low thermal conductivity, and in particular, polyethylene terephthalate (PET) exhibits only V2 or poor thermal conductivity. It becomes clear that there is no. That is, the ethylene-vinyl alcohol copolymer not only has sparring properties but also acts as a barrier to heat conduction.

As thermoplastic polyesters, polyethylene terephthalate, copolyesters mainly containing ethylene terephthalate units, and also containing a small amount of modifying ester units known per se are used for the purpose of the present invention. This polyester only needs to have a molecular weight sufficient to form a film.

In addition, as the gas barrier resin, a copolymer obtained by saponifying a copolymer of ethylene and a vinyl ester such as vinyl acetate is used. Considering moldability and barrier properties, the ethylene content is 15%. Those having a mole content of 60 to 60 moles, particularly 25 to 50 moles, and a degree of carbonation of 96 degrees or more are advantageously used. Other resins that can be used include vinylrizoin chloride resin, high nitrile resin, xylylene group-containing polyamide resin, and high barrier polyester.

Although not required, any adhesive known per se can be used to enhance the adhesion between the preester layer and the sparring resin layer. Copolyester adhesives, polyamide adhesives, -lyester-ether adhesives, epoxy-modified thermoplastic resins, acid-modified thermoplastic resins, etc. are used for this purpose.

Next, as a method for producing a multi-layer i4 phosphor containing a thermoplastic polyester layer and a sparring resin layer, one method is to use a gas barrier resin as an inner layer and an outer layer, or a polyester resin as an inner and outer layer, respectively. In this case, a pipe is formed by coextrusion with an adhesive layer interposed between both resin layers, the multilayer pipe is cut to an appropriate length, and one end of this tube is fused and closed to form the bottom. A mouth portion having an opening and a fitting portion or a screw portion on the outer periphery is formed in the upper part of the other end to form a multilayer preform.

In addition, using a co-injection molding machine equipped with two or more injection machines and a co-injection mold, the inner and outer layers are made of polyester resin, and one or more layers of barrier resin are inserted in the middle to cover the inner and outer layers. A multilayer preform having a bottom and an opening can be obtained depending on the main parts of the preform mold.

In addition, a multi-stage injection machine equipped with three or more injection machines is used to first form a first inner layer preform, then transfer it to a second mold, inject an intermediate layer, and then inject an outer layer in a third mold. It is also possible to obtain a multilayer preform by sequentially transferring multistage molds.

In order to impart heat resistance to the preform obtained in this way, the mouth part containing the threaded part, fitting part, support ring, etc. may be crystallized and whitened by heat treatment at the stage of the preform. After completion of stretch-blowing, the mouth and neck of the unstretched portion may crystallize and turn white.

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 cold stretching, 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 performing biaxial stretching with a blow mold, the blow mold was
The outer layer P of the vessel wall of the multilayer preform is stretched and blown into a heated mold at 0 to 230°C, preferably 130 to 210°C.
Heat treatment (heat set) when ET contacts the inside of the mold
is started. After a predetermined heat treatment time, the blowing fluid is switched to the internal cooling fluid to start cooling the inner layer PET. The heat treatment time varies depending on the thickness and temperature of the blow-molded product, but it brings the above-mentioned crystallinity to the outer layer PET, and is 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 minutes.
seconds, especially on the order of 2 to 20 seconds.

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 gases. Aliphatic hydrocarbon gases and the like 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.

! /I In addition, two molds were used for blowing, and after performing heat treatment (heat setting) within the above temperature and time range in the first mold, the sample was transferred to 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 transferred to a mold and blown again.

The outer layer of the blow molded product taken out from the mold is allowed to cool,
Alternatively, the outer layer P is cooled by blowing cold air.

In the present invention, the gas barrier intermediate layer should have an average thickness of at least 5IRn when used as a container in terms of heat transfer insulation, but if it exceeds 300 μm, stretch formability tends to decrease.

Generally, a range of 20 to 80 μm is preferred. For purposes of the present invention, the PET outer layer should have a thickness of at least 25 mm, with a range of 25 to 200 #i being suitable. The inner layer/outer layer thickness ratio is preferably in the range of 1/3 to 1/1. However, this may not apply depending on the manufacturing method.

In the stretched polyester container of the present invention, the dimensions of the panel-shaped recess vary depending on the size of the container, but generally the circumferential dimension is within the range of 10 to 50 m+, and the axial direction (height direction) dimension is within the range of 40 to 160 m. It is desirable that there be.

Further, it is desirable that the level difference, that is, the difference in diameter, between the large-diameter pillar-shaped convex portion and the small-diameter funnel-shaped concave portion is within the range of 1 to 8 cm.

The stretched polyester container of the present invention has a content of 70 to 9
It is useful as a sealed storage container for hot filling at a temperature of 8°C or heat sterilization at a temperature of 70 to 95°C after filling.

(Effects of the Invention) The container of the present invention has both the excellent container properties and gas barrier properties unique to polyester, and furthermore, the container wall is protected against heat sterilization (heat sterilization) of the contents and the subsequent cooling step. There is an advantage that asymmetric deformation is effectively prevented and, as a result, excellent appearance characteristics are maintained.

(Examples) The present invention will be explained by the following examples. The measurement methods and calculation methods in each example were as follows: 1) Crystallinity, x; Measured in a normal heptane/carbon tetrachloride density gradient tube set at 20°C. A strip of tosu/fl (approx. 2 wa
X 2■) was allowed to settle, and the measured specific gravity, d, was obtained from the position where the sample came to rest.

Then, from the obtained nine measured specific gravity and the value of d, the following formula, (1/d) = ((1-x)/da) + (x
/da), each crystallinity degree, X, was calculated. Here, am is the degree of crystallinity, and the specific gravity value when X is 0 (da=1
．． 335). Also, dc is the crystallinity,
It represents the specific gravity value (dc=1.455) when X is 100%.

11) Oxygen gas permeability of the container, QO2: Put a small amount of water in the container to be measured (in this case, a bottle), replace it with nitrogen gas in a vacuum, and then... Did you modify the contact surface between the torro part and the rubber stopper? After being glued with an adhesive, the bottle was stored for 7 weeks in a constant temperature and humidity chamber at a temperature of 22° C. and a relative humidity of 60% RH.

Thereafter, the concentration of oxygen that permeated into each cell was measured using a gas chromatograph, and the oxygen gas permeability of the container (QO2, unit: 007 m2 day * a) was determined according to the following formula.
tm ) was calculated: QO2 = (mxct/100)/1xOPxA where, m: Amount of nitrogen gas filled into the bottle (ml), t: Storage period in the thermostatic chamber (=49 days), Ct
: Oxygen concentration in the bottle after 8 (vol%), o
P: Oxygen gas partial pressure (=O1209) (atm), A: Effective surface area of the bottle (1n).

Oxygen gas permeability, QO2, is for one type of 1 Torr.
Five pieces of each were measured, and the arithmetic average value was taken as data.

111) Container heat resistance (thermal deformation rate), S: Water temperature is 20°C
Fill the sample container to be measured (in this case, a bottle) with tap water to the full volume to obtain the dripping volume of the sample (■.

9 ml) was measured in advance.

The bottle was then filled with hot water at 85°C, capped and held for 3 minutes, and then cooled with water until the contents (tap water) returned to room temperature (20°C).

After that, the samples were shown to 11 people (humans), and they were asked to answer Oi for samples with no deformation, Δ for samples that were slightly deformed, and × for samples that were clearly deformed. Ta.

Furthermore, after extracting the contents from the sample, 2
The sample was refilled with tap water at 0° C. to the full volume, and the volume of the dripped water (in d in vL) was measured.

The heat resistance (thermal deformation rate) of the container, S (where * is 'l), was calculated according to the following formula, S = 100 x (Vl/VO-1).

Regarding the thermal deformation rate, S, one type of yj? )5 per le
Measurements were carried out for each sample, and the arithmetic mean value of the five samples was used as data.

Example 1 According to the method described in Japanese Unexamined Patent Publication No. 61-254325, the main injection machine was filled with polyethylene Tele7 tarley having a viscosity (intrinsic viscosity) of 0575 (P ash - temperature conduction tA = 5.5).
5 x 10-' m2/hr), and meta-xylylene azinamide resin (MXD6, temperature conductivity = 2.45 x 10" m, manufactured by Mitsubishi Gas Chemical) was supplied to the sub-injection machine.
2/hr -), and a multilayer grid with 2 rods and 3 layers 7
During co-injection molding of Ohm, first, primary injection was performed from the main injection machine at a pressure of approximately 60 kg/cyn2 for 1.3 seconds, then, after stopping the injection of the PET for 0.1 second, the core PET was injected. Start injection, 91-4 seconds late PET
pressure higher than the primary injection pressure (approximately 120ky/=x2
), a predetermined amount (approximately 8 wt%) of molten MXD6 is injected in 0.9 seconds from the sub-injection machine, and then after a delay of 0.05 seconds from the start of MXD6 injection, the main injection machine injects the melted MXD6 at a pressure lower than the primary injection pressure. (A multilayer preform with a wall thickness of approximately 4m was molded by injecting PET with a weight of approximately 40kg/3.The weight of this preform was 59.OF, of which MX
D6 was 7.8 ft%. Also, inner layer PET/outer layer P
The thickness ratio of ET was 215.

The multilayer preform was manufactured by OBM-I manufactured by Toyo Shokuhin Kikai ■.
Using a Q-type biaxial stretch blow molding machine, the cavity was preheated to 100°C, and then biaxially stretched in a blow mold with an internal volume of approximately 158011J whose inner surface of the cavity was heated to 160°C for 9 seconds. After heat setting, the blowing fluid was switched to the internal cooling fluid (air adjusted to +5°C), fluid pressure was applied again for 10 seconds, and then immediately taken out and left to cool, as shown in Figure 1. A cylindrical bottle with an internal volume of 151 smz as shown in FIG.

No J of obtained &tor torso? The dimensions of the flannel-shaped recess are 35 cm in the circumferential direction and 137 cm in the axial direction (height direction).
Met. Further, the difference in level, that is, the difference in diameter between the pillar-shaped convex portion and the tunnel-shaped concave portion was 6.5 m.

Hereinafter, this meter will be referred to as "A1."

For comparison, after preheating the multilayer preform to 100°C using the biaxial stretch blow molding machine,
The cavity surface is set at 19±2℃ and the internal volume is approximately 1
Biaxial stretching blowing was performed for 25 seconds without using the blowing mold 589d and without the heat setting operation as described above.
A cylindrical &
) was molded. The shape and dimensions of the obtained fc&)le body were almost the same as those described above. Below, this bottle is referred to as "B'
It is written as

Two types of PET/MXD6/P obtained in this way
For ET system 3#Dettol, A and B, the inner layer (PET), middle layer (MXD6) and outer layer (PET
) was gently peeled off, and the degree of in-plane orientation (7+m) of the inner layer and outer layer was measured by the polarized fluorescence method described above. For measurements, a polarized fluorophotometer (FO) manufactured by JASCO Corporation was used.
M-2 type) was used.

In addition, the measurement location is P1 shown on the horizontal axis in Figure 6.
Measurements were taken at 24 locations in total, including 6 locations in the &) axial direction and 6 locations in the &) circumferential direction at 4 locations from P4 to P4, and the arithmetic average value thereof was used as data.

Aye) In-plane orientation degree of inner layer PET (L+m
) is 0.813, the in-plane orientation degree (z+m) of the outer layer PET
is 0.756, while the inner layer P for B & Tor
The in-plane orientation degree (t+tn) of ET is 0.394, and the outer layer PE
The in-plane orientation degree (t+m) of T was 0.343.

Next, tests for crystallinity, oxygen gas permeability, and heat resistance were conducted in accordance with the measurement methods and calculation methods described above. Shown below. In this figure, the horizontal axis represents the position (distance from the bottom, cm) in the axial (height) direction from the bottom of the A meter, and the vertical axis represents the degree of crystallinity (%) of each corresponding portion. Here, the crystallinity, or the arithmetic average of the six points in the circumferential direction of the crystallinity obtained from each of the six panel parts in the circumferential direction of the saddle and each part corresponding to their axial direction. It is a value.

From Figure 6, we can see that in the A saddle, especially the 4th flannel part (in the figure,
The difference in crystallinity between the inner layer and the outer layer is large in the P1 to P4 portions, and the crystallinity of the outer layer, X, is 30 for both.
It is known that the degree of crystallinity is greater than % and is greater than the crystallinity of the inner layer by 2 or more.

For comparison, P1 in Figure 6 for bottle B
Table 2 shows the degree of crystallinity (average value of six points in the circumferential direction) of the portion corresponding to P4. It is known from the same table that the crystallinity of the outer layer is less than 30 cm, and the difference in crystallinity between the inner layer and the outer layer is 2 cm or less.

Table 3 shows each of A and B, and for comparison, the wall thickness is approximately 4 mm and the weight is 59 mm. Using the single-layer PET preform C1 (the shape is the same as the preforms A and B), the single-layer PET molded using the above-mentioned 92-axis stretch blow molding machine and under the above-mentioned heat setting conditions was (The shape and dimensions of the body are almost the same as above. Hereinafter, this single-layer metre will be referred to as "C1."), oxygen gas permeability, QO
The results of measuring Z are shown.

The third point is that the oxygen gas permeability of the A bottle is clearly lower than the oxygen gas permeability value of the PET single-layer C bottle, and is also smaller than the value of the B bottle that is not subjected to the heat setting conditions. Known from the table.

111) Heat resistance; A heat resistance test was conducted on three types of &) A, B, and C.

In a visual test conducted by a panel of 11 people (Iruma), 10 people said ○ and 1 for A Metol.
The number of panelists answered Δ, and all 11 panelists answered × for [2] B bottle.

Regarding [3] C bottle, 9 panelists answered ○, and 2
The named person answered Δ.

Next, the measurement results of the thermal deformation rate, S, are as follows: [1] For bottle A, S = 0.07±0.0
For 2chi, [2]B dettle, S = 6.59±
1642%, and in the [3]C bottle, 5=O109±0.04%.

Table 2 Table 3 Example 2 According to the method described in JP-A No. 61-60436, the main extruder was charged with polyethylene terephthalate (PET, temperature conductivity = 5.55X 10) as described in Example 1.
m"/hr,) and fed to the sub-extruder for the barrier agent layer ■ Ethylene-vinyl alcohol copolymer manufactured by Kuraray (ethylene content = 30.1 mol, saponification 1 = 99.6%)
, temperature conductivity -2,00X 1. Also, caprolactam/hexamethylene diammonium adipate copolymer (copolymer with caprolactam content of 78 cm, 6/66 PA, temperature conductivity = 2.85X 10) was added to the extruder for the adhesive layer. -'m''/hr,) were supplied respectively.

Then, by coextrusion method, the layer structure is changed to outer layer (PET)/
Adhesive layer (6/66PA) / Intermediate layer (EVOII) /
A nozzle with three types and five layers consisting of an adhesive layer (6/66PA)/inner layer (PET) was molded. The total thickness of the /guive was: 3.95 mm, and the thickness ratio of each layer was 510.2/110.215 in the order listed above from the outer layer.

Next, 59. Cut each OJF and mold the bottom part and d part, and the weight is 59. ! A five-layer glyphome of i' was obtained.

The multilayer preform described in Example 1 was preheated to 110° C. using the 92-axis stretch blow molding machine, and then the inner surface of the cavity was heated to 145° C. for blowing with an internal volume of about 1580 ml. After biaxial stretching and heat setting for 12 seconds in the mold, the blowing fluid was changed to internal cooling fluid + air adjusted to 5°C, fluid pressure was applied again for 9 seconds, and the mold was immediately taken out and then released. By cooling, the internal volume becomes 1521rn as shown in Figure 1.
1 cylindrical bottle was molded. The shapes and dimensions of the concave portions and convex portions of the obtained bottle body were all the same as in Example 1. Hereinafter, this position will be referred to as "D".

For comparison, the multilayer preform was subjected to the biaxial stretching 7
'r=-After being preheated to 110°C by a molding machine, the heat setting operation as described above is carried out in a blow mold with an internal volume of about 1 ssoi where the inner surface of the mold is set at 19±2°C. A biaxial stretching roll was carried out for 25 seconds without any process, and a perpendicular &) circle having an internal volume of 1,546 mm as shown in FIG. 1 was formed. The shape and dimensions of the concave and convex portions of the bottle body were almost the same as those described above. Hereinafter, this meter will be referred to as "E".

Two types of PET/PA/E obtained from this Nishi 2
VOi-I/PA/PET system 5 layer N, D and E, each outer layer (PET), middle layer +
Adhesive layer (PA/EVOH/PA') and inner layer (PE
T) was gently peeled off, and the degree of in-plane orientation (A+m) of the outer layer and inner layer was measured by the polarized fluorescence method described above. The measurement method and measurement locations were all the same as in Example 1.

In-plane orientation tlJ, CL of outer layer PET for Dmetal
+rn) Ho, 366, in-plane orientation of inner rg4PET 1
i (10 m) is 0.472, which is strange, while the in-plane orientation degree of the outer layer PET (, t + rrr ) for Eylr)
i! 0.310, in-plane orientation of 1aPET g5. (1
+rn) was 0.374.

Next, based on the above-mentioned measurement methods and 1 calculation method,
Crystallinity, enzyme gas permeability, and heat resistance tests were conducted on D and E bottles = 1) Crystallinity and (
The crystallinity of the portion corresponding to P1 to P4 in FIG. 6 is 9x. The crystallinity of outside 1- is all greater than 30 壬,
and the crystallinity of J- is 2 or more higher than that of J-.
Known from the table.

For comparison, Table 5 shows the crystallization jfI%X of the same portion as above for Fl'l-ru. It is known from the same table that the crystallinity of the outer layer is less than 30 cm, and the difference in crystallinity between the outer layer and the inner layer is 2 cm or less.

11) Oxygen gas permeability, QO2; Table 6 shows the oxygen gas permeability for D and E metres,
The measurement results of QO2 are shown. Table 6 shows the single-layer PETyl resin described in Table 3 in Example 1 for comparison.
The results of Cyr) are also shown.

The oxygen gas permeability shown by D&) is clearly smaller than the oxygen gas permeability shown by the PET single-layer C bottle, and also smaller than the value shown by E, Ir, which is not heat set. is known from Table 6.

111) Heat resistance; A heat resistance test was conducted on the two types of &) L, D and E.

In a heat resistance test conducted by a panel of 11 people (humans), 9 people answered O for [1] D&), and 2 answered ・Zanel, and C2J E, r) All 4,211 people answered X.

Next, the measurement results of the thermal deformation rate, S, are as follows: [1] For the D bottle, S = 0.11 ± 003%,
Also, [2] For E & Tor, S=6.74±1.3
It was 7chi.

Table 4 Table 5 Table 6

[Brief explanation of the drawing]

FIG. 1 is a side view of an example of the container of the present invention, FIG. 2 is a bottom view of the container in FIG. 1, FIG. 3 is a sectional view of the container in FIG. 1 along line A-A, and FIG. 4 is a container FIG. 5 is an explanatory diagram showing the state during heat treatment; FIG. 6 shows the degree of crystallinity at each position of the outer layer and inner layer of the container obtained in Example 1. It is a line diagram. 1 is a biaxially stretched polyester container, 2 is a nozzle part, 3 is a shoulder part, 4 is a body part, 5 is a bottom part, 6 is a mother-nel-shaped recessed part, 7 is a pillar-shaped convex part, 20 is a polyester inner layer, 30 is polyester The outer layer 40 is a sparring resin intermediate layer, 50 and 50' are resin adhesive layers, 60 is a mold, and 70 is a cooling fluid.

Claims (1)

[Claims] (1) A container manufactured by biaxial stretch blow molding of a preform consisting of an inner and outer layer made of polyester mainly containing ethylene terephthalate units and at least one intermediate layer made of a gas barrier resin. The body includes pillar-shaped protrusions with a relatively large diameter and a short circumference and panel-shaped recesses with a relatively small diameter and a long circumference, arranged alternately in the circumferential direction, The panel-shaped recess has the function of expanding and contracting in the radial direction of the body in response to pressure changes within the container, and the inner and outer layers of the panel have an in-plane orientation degree ( l+m) is 0.350 or more, and the outer layer of the panel has a crystallinity of 30% or more by the density method and a value that is 2% or more higher than the crystallinity of the inner layer. A heat-deformable gas barrier biaxially oriented polyester container characterized by being heat-set.