JPS61120746A - Multilayer polyester vessel and manufacture thereof - 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 multilayer polyester container with improved dimensional stability, and more specifically, the container wall is prevented from deformation under high temperature, high pressure, or vacuum. The present invention relates to a multilayer polyester container with excellent dimensional stability and appearance characteristics.

Conventional techniques and the current method ・” An amorphous bottomed glyform is produced from a thermoplastic polyester such as polyethylene terephthalate, and this bottomed preform is heated at the stretching temperature of the polyester.
A container formed by stretching in the axial direction of the container and blow stretching in the circumferential direction of the container is disclosed in, for example, U.S. Pat. No. 3,733,
As described in Specification No. 309, it has excellent properties such as transparency, impact resistance, gas barrier properties, rigidity, and pressure resistance, and is widely used as a packaging container for storing various liquids. It has been reached.

However, this polyester container still has a problem with heat resistance, for example, in an atmosphere of 60 to 70°C.
Even when left for 5 minutes, the volume shrinkage rate reaches 1 to 6 inches, and it is also recognized that thermal deformation occurs to the extent that it cannot be used practically at higher temperatures. This tendency is also noticeable in the neck of the container, where the polyester remains substantially unoriented and in an amorphous state. In other words, the container neck is provided with a threaded portion or a stepped portion for engagement with the container in order to ensure sealing with the lid, but these do not have sufficient rigidity.
In some cases, or if the dimensional stability is lacking, a problem arises in that the desired sealing pressure cannot be secured.

In order to prevent these drawbacks, a method of heat setting a stretch blow container has been proposed, for example, in
No. 82366, No. 51-107357, No. 53-7826
No. 8, No. 53-78267, No. 54-71, 54-41
Although many proposals have been made, as seen in Japanese Patent No. 973, etc., they are still unsatisfactory in that the resulting thermal stabilization effect is relatively low and they require complicated treatments.

Furthermore, as a method for improving the rigidity and dimensional stability of the neck of a container, a method is known in which the amorphous neck is whitened (crystallized) by heat treatment, as disclosed in, for example, Japanese Patent Laid-Open No. 51-55566. However, with this method, only the neck of the container turns white and loses its transparency, resulting in a significantly inferior commercial value.

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a polyester container which has significantly improved heat resistance and pressure resistance, and which eliminates the above-mentioned drawbacks of the prior art.

Another object of the present invention is to provide a multilayer polyester container whose heat resistance is significantly improved by chemical means.

Still another object of the present invention is to provide a multilayer polyester container that has improved heat resistance, hot water resistance, pressure resistance, etc., without impairing the transparency etc. that polyester containers normally have.

Structure of the Invention According to the present invention, there is provided a multilayer plastic container made of thermoplastic polyester, comprising an inner surface layer made of thermoplastic polyester; A dimensionally stable laminate comprising a crosslinked product of a compound or a prepolymer thereof containing at least two unsaturated groups and/or oxirane rings in the molecule. An improved multilayer polyester container is provided.

The present invention also provides a composition comprising a layer made of a thermoplastic polyester, a thermoplastic polyester, and a compound containing at least two ethylenically unsaturated groups and/or oxirane rings in the molecule or a prepolymer thereof. This laminate preform is stretch-molded into the shape of a container so that the thermoplastic polyester layer is on the inner surface of the container and the composition layer is on the outside, and the preform is formed. A method for producing a multilayer polyester container is provided, which comprises irradiating the container K with ionizing radiation or ultraviolet light to effect crosslinking of the composition layer.

Effects of the Invention The polyfunctional compound used in the present invention is capable of ion radiation,
Alternatively, it has the property of being easily polymerized and crosslinked by the action of ultraviolet light or the like. In the present invention, the inner surface of the container is made of ordinary thermoplastic polyester, and the outer surface thereof is formed with a layer of a polyester composition containing the above-mentioned polyfunctional compound, and a crosslinked structure is introduced into this polyester composition. The container can be made to have extremely excellent rigidity, dimensional stability, heat deformation resistance, pressure resistance, etc.

Moreover, another advantage of the present invention is that the crosslinked layer present on the outer surface of the polyester substrate only needs to be extremely thin. never lose.

Furthermore, in the present invention, crosslinking of polyester with a polyfunctional compound, that is, a crosslinking agent, is carried out using ionizing radiation or ultraviolet rays, so that it can be quickly formed during thermoforming into a multilayer preform or during stretch molding of a multilayer preform. Crosslinking (
This method has the advantage that it can prevent the formation of precursors (premature), and that the crosslinking agent-containing polyester layer can be effectively crosslinked within a very short period of time after being molded into a container.

Preferred Embodiments of the Invention The present invention will be described in detail below with respect to its preferred embodiments.

Multilayer Polyester Container Although the container of the present invention can be manufactured by thermoforming such as extrusion molding, injection molding, melt sheet molding, melt blow molding, etc., the present invention is particularly useful for stretch molded containers. Stretch molding refers to the above-mentioned polyester or a combination of polyester and gas barrier resin such as ethylene-vinyl alcohol copolymer.
Blow molding, generally at a temperature of 85 to 115°C.
It is formed into a container shape by stretch blow molding, vacuum forming, plug assist molding, pressure molding, compression molding, drawing molding, drawing/ironing molding, bulge molding, impact molding, etc., and utilizes the orientation effect of polyester molecules. It has the advantage of being superior in transparency, mechanical strength, and gas permeation resistance compared to ordinary thermoformed containers.

A particularly suitable container is one in which an amorphous bottomed preform formed by an injection molding method, an extrusion pre-blowing method, etc. is stretched in the axial direction in a blow mold at a stretching temperature, and in a local direction (loop direction). ) is a container obtained by expanding and stretching the container.

In FIG. 1 showing an example of a suitable container (bottle), this bottle #1 includes a body 2, a bottom 6 extending to the lower end of the body, a frustum-shaped shoulder 4 extending to the upper end of the body, and a shoulder. It consists of a neck section (nozzle section) 5 that continues to the upper end of the section. The polyester constituting the body 2 of this bottle 1 is molecularly oriented in two axial directions, that is, in the axial direction of the bottle and in the circumferential direction of the bottle, by stretch blow molding. On the other hand, the neck (nozzle part) 5 of the bottle 1
has an opening 6 at the upper end, and is provided with an engaging part, a threaded part, or a locking part for the lid, such as a screw 7 or a step part 8 for engagement, and further supports the bottle during filling and sealing. A support ring 9 is provided for this purpose.

The polyester constituting the neck portion 5 is substantially unoriented. Furthermore, the shoulder 4 between the neck and the body may be made of completely oriented polyester, or it may gradually change from a biaxially oriented state to an unoriented state from the body to the neck. That's it.

The bottom portion 3 gradually changes from a biaxially oriented state to an unoriented state from the periphery toward the center.

In FIG. 2, which shows an enlarged cross-sectional structure of the container wall of this bottle 1, the bottle container wall consists of a polyester base 11 and polyester, ethylenically unsaturated groups and/or oxiranes provided on the outer surface of the base. It consists of a layer 12 of a crosslinked composition of a compound containing at least two rings per molecule or a prepolymer thereof (hereinafter also simply referred to as a crosslinking agent).

Of course, the laminated structure of the vessel wall is not limited to the above-mentioned two-layer structure; for example, as shown in FIG. Alternatively, as shown in FIG. 4, an ethylene-vinyl alcohol copolymer having a vinyl alcohol content of 40 to 80 moles may be provided on the outside of the inner surface layer 11 of polyester. A gas barrier resin intermediate layer 13 such as a combination may be provided, and a crosslinked material layer 12 of polyester containing a crosslinking agent may be provided on the outermost side. In short, in the container of the present invention, any multilayer laminate structure can be used as long as the polyester is present on the inner surface side and a crosslinked layer of polyester containing a crosslinking agent is present outside this polyester layer. Possible.

Polyester In the present invention, polyethylene terephthalate (PET) is suitably used as the thermoplastic polyester, but copolyesters mainly composed of ethylene terephthalate units and containing other polyester units may be used as long as the essence of polyethylene terephthalate is not impaired. may also be used. Copolymerization components for forming such a copolyester include inophthalic acid, P-β-oxybenzoic acid, naphthalene 2°6-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, and 5-sodium sulfoin. Dicarboxylic acid components such as phthalic acid, adipic acid, sebacic acid or their alkyl ester derivatives, propylene glycol,
1.4-7'tanediol/neopentyl glycol/
Glycol components such as 1,6-hexylene/glycol, cyclohexane dimetatool, ethylene oxide adduct of bisphenol A, diethylene glycol, and triethylene glycol can be mentioned.

The molecular weight of the thermoplastic polyester should be sufficient to form a film, and from the mechanical strength of the container etc. [η
] is 0.01z/F or more, especially 0.051! /f! The above is desirable.

Crosslinking agent The crosslinking agent used in the present invention is a compound or a prepolymer thereof containing at least two polymerizable ethylenically unsaturated groups and/or oxyla/rings per minute.

Suitable examples include, but are not limited to:

(1) Divinyl compound divinylbenzene, allyl compound general formula % formula %) In the formula, R is a divalent to tetravalent organic group, and R is a number from 2 to 4.

For example, diallyl phthalate (DAP), diallyl heptatalate, diallyl adipate, diallyl cricholate, sialyl maleate, sialyl sebacate, triallyl phosphate, triallyl aconitate, allyl trimellitate ester, allyl pyromellitate Esther et al.

011) General formula of acrylic compound R1 R/+00cm ratio=C cap, In the formula, R' is a divalent to hexavalent organic group, R2 is a hydrogen atom or a methyl group, and the number of doors is 2 to 2. A compound of .

For example, 1,6-hexanethioldiacryl) (HDDA
), 1,6-hexanethiol dimethacrylate (HDDM
A), Neopentyl glycol diacrylate, Neopentyl glycol dimethacrylate, Ethylene glycol diac IJv-) (EGDA), Ethylene glycol dimethacrylate (EGDMA), Polyethylene glycol diacrylate (PEGMAA)
), polyethylene glycol diacrylate) (PEGHA
), polypropylene glycol diacrylate, polyethylene glycol diacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, pentaerythritol diacrylate, 1,4-butanediol diacrylate, trimethylolpropane triacrylate,
Trimethylolpropane trimethacrylate, pentaerythritor triacrylate, dipentaerythritol hexaacrylate, tetramethylolmethanetetraacrylate, N, N, N/, N/-tetrakis (β-
hydroxyethyl) ethylenediamine acrylic acid ester, etc.

(iv) Allyl-acrylic compound allyl acrylate, Allyl methacrylate.

(V) Acrylamide compound N', ,V/-methylenebisacrylamide, N
, N'-methylenebismethacrylamide.

(VD Oxirane Compound General Formula In the formula, Rs is an organic group having a valence of P+q, and R2
is a hydrogen atom or a methyl group, Y is a -COO- group or a Group 4 O- group, and p and q are each positive under the conditions that P is an integer of 1 or more and P+9 is 2 or more. A compound of which is an integer.

, For example, allyl glycidyl ether, glycidyl methacrylate, glycidyl (2-methyl acrylate), glycidyl/I/(2-butyl acrylate),
Glycidyl crotonate, 2,2-bis(6-allyl-
4-glycidyloxyphenyl)propane, 1,1-bis(6-allyl-4-glycidyloxyphenyl)cyclohexane, (2-allylphenyl)-glycidyl ether, (2,6-sialylphenyl)-glycidyl ether, 1. 4-diglycidyloxy-2,6-diallylbenzene, 2,2-bis(5,5-diallyl-4-
glycidyloxyphenyl)propane, (2,4,
6-) IJ-allylphenyl) glycidyl ether,
5,5'-dially/L/-4,4'-diglycidyloxypenzophenone, bis(3-allyl-4-diyloxyphenyl)ether, bis(3,5-diallyl-4-glycidyl) oxyphenyl) sulfone, etc.

(S/i prepolymer) A prepolymer derived from the components (1) to (1) above or a prepolymer containing the two unsaturated groups described above.

Examples of the latter include polyurethane acrylate, evokiacrylate, polyether acrylate, and polyester acrylate.

These crosslinking agents can be used alone or in combination of two or more, and can also be used in combination with monofunctional monomers to form a polymerized crosslinked layer.

For example, triallyl cyanurate and diallyl phthalate are solid crosslinking agents, but they can be dissolved in other liquid crosslinking agents or monofunctional monomers and used to form a crosslinked polyester layer.

Suitable examples of monofunctional monomers include, but are not limited to, the following:

Acrylic acid (AAc), Methacrylic acid (MAAc), Methyl acrylate # (M, 4), Methyl methacrylate (HMA), Ethyl acrylate (EA), Ethyl methacrylate (ERA), Butyl acrylate (BA), Butyl methacrylate (BMA), hexyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, inoctyl acrylate, lacryl methacrylate, 2-hydroxyethyl acrylate (HEA), 2-
Hydroxyethyl methacrylate (HEMA), 2-
Hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 3-chloro-
2-hydroxypropyl methacrylate, N N'-dimethylaminoethyl acrylate, N,
N/-dimethylaminoethyl methacrylate, N,N'-diethylaminoethyl acrylate, N,N
/-diethylaminoethyl methacrylate, glycidyl acrylate) (G, 4), glycidyl methacrylate (GMA), carpitol acrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, dicyclopentadienyl acrylate, cyhydrodicyclobentadi enyl methacrylate, ynyl acrylate, acrylamide (AArIL), methacrylamide (JfAm), N-methylolacrylamide (N,,,MAM), N
-Diacetone acrylamide (DAAM), N-vinylpyrrolidone, maleic acid, itaconic acid, styrene (57'), acrylonitrile (AN), vinyl acetate (VAc), vinyltoluene (VT).

To a polyester composition containing a crosslinking agent According to the present invention, the above-mentioned crosslinking agent is blended with a thermoplastic polyester, and this composition is formed into a laminate together with the unblended polyester. The amount of crosslinking agent added to the thermoplastic polyester should be sufficient to introduce a crosslinked structure sufficient for dimensional stability into the thermoplastic polyester, and generally speaking, the amount of crosslinking agent added per 100 parts by weight of thermoplastic polyester is It is preferably blended in an amount of 0.1 to 20 parts by weight, particularly 0.5 to 10 parts by weight.

That is, if the amount of the crosslinking agent is less than the above range, it is difficult to introduce a sufficient crosslinked structure between the polyester molecular chains, whereas if the amount of the crosslinking agent is more than the above range, this The layers of the composition tend to become too brittle after crosslinking.

The thermoplastic polyester and the crosslinking agent are preferably mixed uniformly prior to manufacturing the container or the preform for forming the container. This mixing operation is performed using a roll, Pan Bali mixer,
Although this can be carried out in a mixing device such as a kneader, generally both materials are fed into a machine such as a blender or an injection machine and melt-kneaded, or the crosslinking agent is mixed with the polyester in an extruder or injection machine. can be added to crosslink the polyester and the crosslinking agent.

According to the present invention, a laminate preform is formed that includes a thermoplastic polyester layer and a layer of a polyester composition containing a crosslinking agent. The preform of the laminate may be a bottomed cylindrical preform used for stretch blow molding,
Further, it may be a disc-shaped preform used for plug assist molding, pressure molding, or drawing molding.

The multilayer preform can be formed by lamination techniques such as coextrusion molding, co-injection molding, multistage injection molding, extrusion coating, and hot pressing of film layers. Coextrusion uses two extruders, one for polyester and one for crosslinked polyester, and extrudes two streams of molten resin through a multilayer die into a pipe, parison, or sheet. To manufacture a bottomed preform, the pipe is rapidly cooled and cut to a predetermined size, and then a closed bottom is formed by compression molding and bottoming, or the parison to be extruded is placed in a split mold. Pre-rolling is performed to form a preform with a bottom.

In co-injection molding, an injection cylinder for polyester and an injection cylinder for cross-linking polyester are used, and these resin flows are injected into the injection mold to form a cylindrical or disk-shaped preform with a bottom. Let it form. Furthermore, in the multi-stage injection method, a primary preform made only of polyester is formed, then this primary preform is inserted into a secondary injection mold, and a polyester composition containing a crosslinking agent is injected onto the outer surface of the primary preform. , to form the final preform.

These multilayer preforms were placed so that the polyester layer was on the inner surface of the container and the crosslinking agent compounded composition was on the outside.
Stretch and mold into the shape of a container. During stretch molding, the preform is maintained at a temperature that allows stretching, and the preform is stretch molded so that molecular orientation of the polyester occurs at least in the axial direction of the container.

For example, in the case of a cylindrical preform with a bottom, this preform is stretched in an axial direction and then stretched in a circumferential direction to form a bottle-shaped container.

Further, in the case of a disc-shaped preform, it is made into a cup-shaped or wide-mouthed bottle-shaped container by the above-mentioned plug assist molding, pressure forming, drawing molding, or the like.

The stretching temperature is generally in the range of 85 to 115°C, particularly 90 to 110°C, and in the case of biaxially stretched bottles, the temperature is 1.5 to 6 times, especially 1.8 to 2 times in the axial direction. .2 times, circumferentially 1.5 to 5 times, especially 2 to 2.5
It is preferable to set the stretching ratio to 2 times. - In the case of axially stretched cup-shaped or wide-rottle containers, the stretching ratio of the container body (
It is preferable that the stretching ratio (from the thickness) is 2 to 10 times, particularly 5 to 6 times.

According to the present invention, the container thus formed is irradiated with ionizing radiation or ultraviolet rays to cause crosslinking of the polyester composition containing a crosslinking agent. That is, by employing the above-mentioned initiation means, crosslinking of the composition during container molding can be suppressed while crosslinking can be efficiently performed after container molding. Crosslinking, ie, curing, by radiation such as an electron beam is particularly desirable.

Curing methods using radiation such as electron beams do not require special chemicals such as initiators, have short curing times, and can be cured at low temperatures, so there is no effect of heat on the polyester base.
It is sufficient to irradiate only the necessary areas, and advantages such as energy saving and excellent properties of the polymerized cured film can be achieved.

As an electron beam source, the accelerating voltage is 100 to 3000 KV.
Many electron beam accelerators are used, such as Van de Gras
Any device such as a 7-type scanning device, a curtain type device, or an electrocurtain can be used. The irradiation dose varies depending on the type of crosslinking agent and coating thickness, but generally speaking, it is 0.1 to 50 megarads (Mr
cLd), particularly from a range of 5 to 50 megarads, the dose that produces the desired degree of crosslinking may be determined.

The crosslinking reaction by the crosslinking agent used in the present invention is a radical reaction. When a polyester composition containing a crosslinking agent is irradiated with an electron beam, radicals are generated in the polyester chain and/or the crosslinking agent through excitation and ionization of molecules. These radicals react with the crosslinking agent to advance grafting, chain growth, and crosslinking, and the molecular chains become networked, resulting in hardening. In electron beam irradiation,
Because the dose rate, therefore energy, and radical concentration are high, crosslinking and curing proceed rapidly and complete polymerization and curing instantly, and the resulting cured film has an extremely high crosslinking density.
This provides the advantage of imparting extremely excellent dimensional stability to the container and preventing deformation under high heat or pressure.

Other irradiation conditions may vary widely. For example, the dose rate can be varied, for example, in the range of 0.01 to 50 Mrad/sea, and the temperature during irradiation can be varied as appropriate, but room temperature is generally sufficient. The irradiation time is generally 1
Less than a second is sufficient. Since crosslinking and curing is a radical reaction, it is preferable to carry out the process in an inert atmosphere such as nitrogen, but if the crosslinking agent-containing polyester composition is not exposed to the air (if it is present as an intermediate layer) In this case, the irradiation atmosphere may be in the air.

Polymerization curing by electron beam irradiation is desirable from the viewpoint of workability, but
Gamma rays from radioactive isotopes such as cobalt-60 and cesium-167 can also be used as the radiation source.

An ultraviolet curing method can be mentioned as an important polymerization curing method next to electron beam curing. In this case, a photopolymerization initiator is previously included in the polyester together with a crosslinking agent, and the polyester composition containing the crosslinking agent and initiator is irradiated with ultraviolet rays.

Examples of photopolymerization initiators include benzophenone, methoxybenzophenone, acetophenone, benzyl, benzoyl,
Aromatic carbonyl-containing compounds such as benzoin ethyl ether, benzyl dimethyl ketal, and ethylene bis(benzoylbenzamide) are preferably used, but all known photopolymerization initiators can be used and are not limited to those exemplified above. . The amount of the photopolymerization initiator used may be a so-called catalytic amount, and is preferably 0.01 to 20 parts by weight, particularly 0.1 to 10 parts by weight, per 100 parts by weight of the crosslinking agent or crosslinking agent composition.

The light source used for photopolymerization and curing can be any light source that emits ultraviolet rays, such as high-pressure mercury lamps, low-pressure mercury lamps, hydrogen discharge tubes, xenon discharge tubes, arc lamps, and the like.

The atmosphere for ultraviolet irradiation may be in the air, and room temperature is sufficient, but in order to accelerate the polymerization curing reaction,
The crosslinking agent-containing polyester composition layer can be heated to a temperature of 80°C to 80°C.

The duration of ultraviolet irradiation varies depending on the output of the light source and the type of crosslinking agent, but in most cases, exposure for several seconds is sufficient. In the method of the present invention, the crosslinking agent-containing polyester layer is
Since it may be extremely thin, such as 50 μm to 50 μm, it has the advantage that the polymerization and curing reaction by ultraviolet rays can be carried out extremely efficiently.

Characteristics of the processing container The processing container according to the present invention has a cured layer of polyester crosslinked with a crosslinking agent, that is, a compound containing a plurality of ethylenically unsaturated groups and/or oxy2F groups, on the outside of the polyester. It has the advantage that its dimensional stability is significantly improved and deformation due to heat or pressure is significantly prevented.

For example, when a normal biaxially stretched polyester bottle is immersed in boiling water at 100°C, its volumetric shrinkage rate is 30 cm and its external shape is significantly deformed. In the case of bottles provided with a cross-linked layer, the volumetric shrinkage rate is 5 cm or less, and no deformation of the external shape is observed. In addition, when measuring the buckling pressure at the bottom of a bottle filled with water at 80°C, it was found that, for example, in a normal polyester bottle, it was 10 to 9/d gauge, but in the bottle treated with the present invention, there was no deformation. pressure is 40
kft/art”.Furthermore,
A metal cap was fastened to the neck of this bottle and the sealing pressure was measured at a temperature of 95°C.The untreated bottle leaked at a pressure of 1kg7am'', while
In a bottle whose neck outer periphery was treated according to the present invention, 10
It was confirmed that the sealed state was maintained even at a pressure of 100 kg/cm''.

Moreover, in the present invention, these properties are improved when the layer of polymerized crosslinked material has a thickness of 1 to 50 μm, particularly 10 to 50 μm.
It comes in an extremely thin layer. This is related to the fact that the crosslinking agent used in the present invention is radically polymerizable and has a highly crosslinked (reticulated) structure with the polyester molecular chain. The fact that this layer is highly reticulated indicates that the gel fraction of this layer is 8.
0- or more, especially 90% or more, it is also possible that in the infrared absorption spectrum of the layer, there is almost no characteristic absorption of C-C double bonds or oxirane rings, or that the original crosslinking agent This is confirmed by the fact that it has decreased significantly compared to the previous year.

Example The invention is illustrated by the following example.

Example 1゜Inner and outer layer extruder with built-in full-flight screw with a diameter of 65mm and an effective length of 1430xm, a diameter of 50u,
Polyethylene terephthalate (cPET) with an intrinsic viscosity of 1.0 was used in the extruder for the inner and outer layers using an extruder for the middle layer equipped with a full-flight screw with an effective length of 1 l 100 iB and a pipe extruder equipped with a 6-layer ring die. , a PET composition containing 6 parts of ethylene bis diallyl isocyanurate and 2 parts of diallyl glycidyl isocyanurate per 100 parts of PET of the same type as the inner and outer layers was supplied to the extruder for the intermediate layer, and six layers of two types were laminated. The pipe is extruded through the die into water and cooled. The outer diameter of this pipe is 50 m, the inner diameter is 22 m, and the thickness of each layer is 2.5 WM for the inner layer, 12 m for the outer layer, and 0.5 WM for the middle layer. !, weight 5
511C was cut, one end of the pipe was heated to about 220°C to form a closed semi-spherical bottom, and the other end was heated to 150°C to promote neck crystallization and a threaded part and neck ring were formed to form a pipe with a total height of 146 mm. A preform was obtained.

This preformed product is heated to 105°C, and is stretched in the vertical axis direction in a blow mold while being blown and stretched in the horizontal axis direction.Almost simultaneously, the preform is biaxially stretched and the bottom shape is made to have an internal volume of 1500 cc.
A multilayer stretched bottle was obtained.

A scanning electron beam irradiation device with an electron beam acceleration voltage of 600 KV was used for this multilayer stretched bottle, and an electron source of 10, OMra
d irradiated. The container after irradiation showed no phenomena such as whitening (it was a good transparent container).

The results of heat resistance and pressure resistance are shown in Table-1.

For comparison, a multilayer stretched bottle similar to the example was obtained except that the outer layer was made of polyethylene terephthalate (PET) having the same intrinsic viscosity of 1.0 as the inner layer.

Comparative Example 1 is a container irradiated with an electron beam of 10.0 Mratl, and Comparative Example 2 is a container that is not irradiated with an electron beam.
The results are shown in Table 1.

Resistance Example 1 0.0 0.5 1.1
3.1 Thermal C Comparative Example 1o, 11.8 8.4 312-body jet silk Comparative Example 2 0.1 1.8 8.5
515 rate* Example 1 45.0 43.5 41.0
59.8 Compression Comparative Example 1 42.1 20.8 10.5
-Strength Comparative Example 2 42.0 21.0 8.8
-Measurement method for jars υHeat resistance (volume shrinkage rate) Fill a container with water at a specified temperature, leave it for 60 seconds, remove the water, and express the change in the content.2) Compressive strengthWater at a specified temperature Fill a container with a notch in the mouth up to the shoulder and hold for 60 seconds, then compress at a speed of 50 with Tensilon.
Total bending strength of the container in ml sin.

Example 2 Using a multistage injection molding machine, polyethylene terephthalate (PET) with an intrinsic viscosity of 0.7 was injection molded to a length of 110 mm.
A preform with an inner diameter of 25 mφ and a wall thickness of 2.0 mm was formed, and then the PET composition blended into the preform was injected into a bottom shape to form a multilayer preform with a body wall thickness of 3.5 mm. After heating this multilayer preform to a temperature of 105°C, it was stretched and blown into a bottom shape with an average wall thickness of 300 μm.
A multilayer bottle with an internal volume of 1500 cc was obtained. This multi-layer stretched blow bottle has a scanning type T+ with an electron beam acceleration voltage of 500KV.
The electron beam was irradiated with a dose of 15 Mrali using a beam irradiation device. After irradiation, the container was transparent and yellowish. Table 2 shows a comparison of the heat resistance and heat compressive strength with that of a container similar to the example but not irradiated.

Table-2 Jar heat resistance (body lateral yield N rate and slow filling temperature 50℃ 70℃ 80℃ 96℃Example 2 0.0 0.5 1.1 4
．． 0 Comparative example 0.1 1.7 8.3
30.0 Qin heat resistant compressive strength Y/cm” Filling temperature 50℃ 70℃ 80℃ 96℃Example 2 42.0 41.0 37.0 50
．． 6 Comparative example 40.5 60.0 21.0
Not measurable The measurements in Table 2 are the same as those in Example 1.

Example 6: Polyethylene terephthalate with an intrinsic viscosity of 0.75 was injected by co-injection molding, and after a delay of 1.5 seconds, the intrinsic viscosity was 0.75.
A resin blended with 100 parts of polyethylene terephthalate of 80 and 5 parts of epoxy acrylate was injected and placed into the primary injected resin to form a multilayer preform with a length of ±125, an outer diameter of φ58, and a wall thickness of 511@. , the preform was heated in a heating pot, and then stretched and plow-molded at the next plow station to obtain a wall thickness of 0.4 m and an inner volume of 1800 m.
A multilayer stretched PET container was obtained. The container was irradiated with a dose of 20 Mrad using a scanning electron beam irradiation device f with an electron beam acceleration voltage of 500 KV. The container after irradiation showed no change in appearance and had good heat resistance and heat pressure resistance.

The results are shown in Table 6 in comparison with a container similar to the example but not irradiated.

Table 6: Hata Heat Resistance (Volume Shrinkage Rate) % East Heat Resistance Compressive Strength kg/cm'' Note that the measurement in Table 6 is the same as the measurement method in Example 1.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of the multilayer polyester container of the present invention, FIG. 2 is an enlarged cross-sectional view of the container wall cross section of the container shown in FIG. 1, and FIGS. 6 and 4 are cross sections of the container wall. FIG. 3 is an enlarged view showing several examples of structures. 1 is a container (bottle), 11 is a polyester base, and 12 is a crosslinked layer of a composition of polyester and a crosslinking agent.

Claims (2)

[Claims] (1) A multilayer plastic container made of thermoplastic polyester, comprising an inner surface layer made of thermoplastic polyester, and a layer provided outside the inner surface layer and containing the thermoplastic polyester and an ethylenically unsaturated group and/or A multilayer polyester container with improved dimensional stability characterized by comprising a laminate comprising a layer made of a crosslinked product of a composition comprising a compound containing at least two oxirane rings in the molecule or a prepolymer thereof. (2) Contains a layer made of thermoplastic polyester and a layer of a composition made of thermoplastic polyester and a compound containing at least two ethylenically unsaturated groups and/or oxirane rings in the molecule or a prepolymer thereof. A laminate preform is manufactured, and this laminate preform is stretch-molded into the shape of a container so that the thermoplastic polyester layer is on the inner surface of the container and the composition layer is on the outside. A method for producing a multilayer polyester container, which comprises irradiating the composition layer with radiation or ultraviolet rays to crosslink the composition layer.