CA1301089C - Multilayered container and process for production thereof - Google Patents
Multilayered container and process for production thereofInfo
- Publication number
- CA1301089C CA1301089C CA000574081A CA574081A CA1301089C CA 1301089 C CA1301089 C CA 1301089C CA 000574081 A CA000574081 A CA 000574081A CA 574081 A CA574081 A CA 574081A CA 1301089 C CA1301089 C CA 1301089C
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Abstract
Abstract of the Disclosure A biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermoplastic resin (resin A) other than resin B
and having excellent gas-barrier property and delamina-tion strength. The container comprises a substantially non-oriented mouth portion composed of resin A, a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately and a portion com-posed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately. A portion having a small radius of curvature where delamination tends to occur is formed in a three-layer structure. A process for producing the container is also provided.
and having excellent gas-barrier property and delamina-tion strength. The container comprises a substantially non-oriented mouth portion composed of resin A, a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately and a portion com-posed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately. A portion having a small radius of curvature where delamination tends to occur is formed in a three-layer structure. A process for producing the container is also provided.
Description
~13~ 8~
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to a multilayered con-tainer having a multilayered structure, and more specifi-cally, to a multilayered container having excellent delamination resistance, transparency, gas-barrier property and mechanical strength and a process for production thereof.
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to a multilayered con-tainer having a multilayered structure, and more specifi-cally, to a multilayered container having excellent delamination resistance, transparency, gas-barrier property and mechanical strength and a process for production thereof.
2. Description of the Prior Art 1~ In recent years, hollow containers of thermo-plastic resins have been widely used to hold cosmetics, foods and drinks because of their various advantages such as light weight and safety against bursting. In parti-cular, the development of hollow containers composed of 1~ polyethylene terephthalate has rapidly advanced as a result of the improvement of the biaxial stretch-blow molding technique.
Biaxially oriented containers composed of a thermoplastic polyester resin, typically polyethylene 2C terephthalate, do not have all the necessary properties.
For example, they have insufficient gas-barrier property to oxygen and carbon dioxide gas, and will impair the flavor of foods and drinks requiring a high level of gas-barrier property.
2~ In an attempt to eliminate this defect, a multilayered-container was proposed which is produced by injecting a thermoplastic polyester and a m-xylylene group-containing polyamide resin (MX nylon~ as a gas-barrier thermoplastic resin in this sequence into a 30 single mold from separate injection cylinders to form a three-layered parison composed of an inside and an out-side layer of the thermoplastic polyester resin and an inside core layer of M~ nylon, and biaxially blow-molding ~3~L01~9 the parison ~Japanese Laid-Open Patent Publications Nos.
128516~1982 and 128520/1982; and corresponding U. S.
Patent No. 4,335,901). If in this method, the amount of MX nylon injected is decreased in an attempt to decrease the thickness of the inside core layer, the inside core layer is formed only partly, and the resulting container has insufficient gas-baerier property.
The present inventors developed an improvement over this prior method in which three layers of the thermoplastic polyester resin and two layers of the ~X
nylon are laminated alternately to form a five-layer structure by injectin~ ~he thermoplastic polyester resin, MX nylon and again the thermoplastic polyester resin in this sequence, and consequently, the amount of the MX
nylon injected can be decreased from that in the prior art although there are two layers of the MX nylon. This method was applied for a patent tJapanese Laid-Open Patent Publication No. 240409/1985 and corresponding U. S. Patent Application Serial No. 731,953 and Japanese Laid-Open Patent Publication No. 108542/1986 and corres-ponding U. S. Patent No. 4,728,549?~
A method was also proposed in which the thick-ness of the inside core layer i8 decreased by first injecting the resin forming the inside and outside layers and then simultaneously injecting the resin forming the inside and outside layers and the resin forming the inside core layer ~Japanese Patent Publication No.
16326/19~5 corresponding to U. S. Patent No. 4,174,413~.
In the resulting three-layer structure, the inside core layer is deviated toward either of the inside an~ outside layers.
Generally, thermoplastic gas-barrier resin (resin B hereinafter) including MX nylon have poor affinity for resins (resin A hereinafter) such as thermo-plastic polyester resins, and the delamination resistanceis weak. If a curved surface having a small radius of ~3~ 9 curvature exists in the rib portion of the container and that curved surface is stretched by the gas pressure of the contents, delamination between resln layers tends to occur at the stretched part. The delaminated part sep-arates into two films, and the container looks slightlywhite to present an undesirable appearance. The present inventors extensively studied this problem, and finally found that ~hen a curved surface having a radius of curvature of not more than 5 mm on the rib portion o~ the container is stretched by the gas pressure of the con-tents, delamination occurs with a high probability in a par~ composed of five resin layers, whereas it occurs with a very low probability in a part composed of three resin layers; and that the gas-barrier property of the same amount of the gas-barrier resin is better at the part composed of five layers containing two layers of the gas-barrier resin than at the part composed of three resin layers containing one layer of the gas-barrier resin. This finding has now led to the present inven-tion.
SUMMARY OF THE INVENTION
, _ It is an object of this invention to provide ablow-molded container free from delamination between resin layers.
Another object of this invention is to provide a blow-molded container having excellent gas-barrier property and mechanical property and being free from delamination.
Still another object of this invention is to provide a blow-molded container having excellent gas-barrier property and mechanical strength and being free from occurrence of delamination at a part having a radius of cur~ature of not more than 5 mm in the rib portion of the container.
A further object of this invention is to pro-vide a blow-molded container which does not undergo ~3~
delamination even after it is used for a long period of time as a container for holding potable watee which require gas-barrier proper~y to oxygen and/or carbon dioxide gas.
The objects of this invention are achieved by a biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermo-plastic resin (resin A) other than resin B; wherein the mouth portion is composed of resin A and substantially non-oriented, and the remainder consists of a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately and a portion com-posed of three layers of resin A and two layers of resin B which are laminated with the res.in A layer and the resin B layer occurring alternately.
BRIEF ~ESCRIPTION OF TEiE ACCOMPANYING DRAWINGS
Figures 1, 2 and 3 are partly broken-away front views of examples of the blow-molded container of this inventiOn;
Figure 4 is an enlarged view of a portion encircled in a broken line in Figure l;
Figure 5 is a sectional view taken on line A-A
of Figure 2;
Figure 6 is a sectional view, corresponding to Figuee 5, in which the resin B layer is located on the outside;
Figure 7 is a schematic view of an ex~mple vf an apparatus used to produce the parison in the present invention;
Figures 8 to 10 are sectional views of examples of the parison obtained by the present inYention;
Figures 11 to 14 are sectional views showing the process of forming the parison shown in Figure 8; and 3s Figures 15 to 18 are sectional views showing examples of parisons formed under inappropriate condi tions.
~3~ g DETAILED DBSCRIPTION OF PREFERRED EMBODIMENTS
The present invention will be described by reference to the accompanying drawings.
Figures 1 t 2 and 3 are partly broken-away front views showing examples of the container of the invention.
Figure 1 shows a self-supporting stretch blow-molded bottle. Figure 2 shows a base cup-equipped stretch blow-molded bottle. Figure 3 is a self-supporting stretch blow-molded bottle having ribs existing at the lower part of its body portion.
In the example of Figure 1, the bottle includes a vertical rib 7 as a site having a small radius of curvature at its shoulder portion 4 and a lateral rib 8 as a site having a small radius of curvature at its lS bottom portion S. Hence, the shoulder portion 4 and the bottom portion S are each of a three layer structure composed of two layers o~ resin A and one layer of resin B, and the body portion 6 of the bottle is of a five-layer structure composed of three layers of resin A and two layers of resin B. Figure 4 is an enlarged view of the circular part shown by a broken line in Figure 1 presented in order to clearly show the resin B layer shown by a solid line in Figure 1.
In the example of Yigure 2, the bottle has a vertical rib 9 and a lateral rib 10 as sites having a small radius of curvature at its shoulder portion 4.
Thus, the ~houlder portion is of a three-layer structure composed of two layers of resin A and one layer of resin B, and the body portion 6 and the bottom portion 5 are 3~ each of a five-layer structure composed of three layers of resin A and two Iayers o~ resin B. In Figure 5 which is an enlarged view taken along line A A of Fig~re 2, the left side is the inside of the bottle and the right side is the outside of the bottle~
In the example of Figure 3, the bottle has a lateral rib 7 and a vertical rib 8 as sites having a l3~1b89 small radius of curvature at its body portion 6. Hence, the shoulder portion 4 and the body portion 6 above the lateral rib 7 are of a five-layer structure composed of three layers of resin A and two layers of re in B, and the bottom portion below the lateral rib 7 is of a three-layer structure composed of two layers of resin A
and one layer of resin B.
As shown in Figures 1 to 3, thle opening end part 3 of the mouth portion of the bottl~e and its vicinity are substantially unstretched and composed of resin A. The reason for this i5 that since this part has a small surface area and a large thickness~ it does not so much affect the gas-barrier property of the entire bottle, and that the gas-barrier resin ~resin B) generally has high hygroscopicity, and when not oriented, absorbs water and becomes whitened to present an undesir-able appearance.
When the radius of curvature of the container becomes small and the resin layers of the bottle are stretched under internal pressures during use, an inter-layer shear strain is generated and delamination of the eesin layers tends to occur. The stretch blow-molded container from a parison is for~ed by introducing a high-pressure gas into a heated parison and inflating it 25 f rom inside and pressing it against the mold. Hence, a bent part of the container has a sharp shape of a small radius of curvature faithfully following the shape of the mold as it is near the outside close to the mold. In Figure 6 which is an enlarged view taken along line A-A
in Figure 2, the resin B layer is positioned close to the outside. Since the radius of curvature of the resin B in the the rib portion of the container is smaller than that of the resin B layer in Figure 5, delamination tends to occur in comparison with the case of Figure 6~ Accord-3~ ingly, it is preferred to position the resin B layer nearthe inside as in Figure 5.
~3~
On the other hand, since the gas-barrier resin generally decreases abruptly in gas-barrier property as the humidity approaches 100 %, it is preferred to posi-tion ~he gas-barrier resin layer (re~in B layer) at a part near the outside which is remote from the contents.
In the present invention, there are two gas-barrier layers in that portion of the container which is other than the sites having a small radius of curvature in the rib portion, and one of them is located near the outside.
Accordingly, the reduction of the gas-barrier property is little.
As stated above, th~ blow-molded container of this invention comprises a substantially non-oriented portion of resin A including the opening end of the mouth portion of the container, and the remainder consisting of a portion composed of two layers o resin A and one layer of resin B alternately }aminated and a portion composed of three layers of resin A and two layers of resin B.
The container can be produced by producing a parison having the corresponding layer structure and then bi-axially stretching and blow-molding the parison.
The method of producing the parison will be described.
Figure 7 is a schematic view showlng a device 2S for producing a parison which is a precursor of the container of the invention. This device is provided with a cylinder 12 for resin A (reference numeral 11 and a cylinder 13 for resin B ~refeeence numeral 2) and are connected to a mold 14 at a nozzle portion lS. The resins A and B melted in tbe cylinders 12 and 13 re-spectively are injected simultaneously or alternately into a cavity 18 of the mold 14 via a hot runner portion 16 and a g2te 17.
The parison as a precursor of the container of the invention is formed by properly combining simultane-ous injection and alternate injection of the resins A and 13(~1~8~
B using the above device. This combination differs depending upon the positions at which three layers and fives layers are formed. In the following description, typical examples shown in Figures 8 to 10 will be taken up. In the case of Figure 8 in which three layers, five layers and three layers are formed f rom the opening end part of the mouth portion toward the bottom portion ~3~/3 layers); in the case of Figure 9, three layees and five layers are formed from the opening end part of the mouth portion toward the bottom portion ~3/5 layers); and in the case of Figure 10, five layers and three layers are formed from the opening end part of the mouth portion toward the bottom portion (5/~ layers).
3/5/3 layers lS A parison of the 3/S/3 layer structure is formed by the following procedure.
~ 1) The total amount of resin B to be injected is adjusted to 1 to 2S ~ of the volume of the cavity.
(2) Only resin A is iniected in an amount corresponding to 20 to 70 % of the volume of the cavity (step I).
~ 3~ Resin B in an amount 5 to 35 % of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of resin B to be in-jected are simultaneously injected (step II ) .
Biaxially oriented containers composed of a thermoplastic polyester resin, typically polyethylene 2C terephthalate, do not have all the necessary properties.
For example, they have insufficient gas-barrier property to oxygen and carbon dioxide gas, and will impair the flavor of foods and drinks requiring a high level of gas-barrier property.
2~ In an attempt to eliminate this defect, a multilayered-container was proposed which is produced by injecting a thermoplastic polyester and a m-xylylene group-containing polyamide resin (MX nylon~ as a gas-barrier thermoplastic resin in this sequence into a 30 single mold from separate injection cylinders to form a three-layered parison composed of an inside and an out-side layer of the thermoplastic polyester resin and an inside core layer of M~ nylon, and biaxially blow-molding ~3~L01~9 the parison ~Japanese Laid-Open Patent Publications Nos.
128516~1982 and 128520/1982; and corresponding U. S.
Patent No. 4,335,901). If in this method, the amount of MX nylon injected is decreased in an attempt to decrease the thickness of the inside core layer, the inside core layer is formed only partly, and the resulting container has insufficient gas-baerier property.
The present inventors developed an improvement over this prior method in which three layers of the thermoplastic polyester resin and two layers of the ~X
nylon are laminated alternately to form a five-layer structure by injectin~ ~he thermoplastic polyester resin, MX nylon and again the thermoplastic polyester resin in this sequence, and consequently, the amount of the MX
nylon injected can be decreased from that in the prior art although there are two layers of the MX nylon. This method was applied for a patent tJapanese Laid-Open Patent Publication No. 240409/1985 and corresponding U. S. Patent Application Serial No. 731,953 and Japanese Laid-Open Patent Publication No. 108542/1986 and corres-ponding U. S. Patent No. 4,728,549?~
A method was also proposed in which the thick-ness of the inside core layer i8 decreased by first injecting the resin forming the inside and outside layers and then simultaneously injecting the resin forming the inside and outside layers and the resin forming the inside core layer ~Japanese Patent Publication No.
16326/19~5 corresponding to U. S. Patent No. 4,174,413~.
In the resulting three-layer structure, the inside core layer is deviated toward either of the inside an~ outside layers.
Generally, thermoplastic gas-barrier resin (resin B hereinafter) including MX nylon have poor affinity for resins (resin A hereinafter) such as thermo-plastic polyester resins, and the delamination resistanceis weak. If a curved surface having a small radius of ~3~ 9 curvature exists in the rib portion of the container and that curved surface is stretched by the gas pressure of the contents, delamination between resln layers tends to occur at the stretched part. The delaminated part sep-arates into two films, and the container looks slightlywhite to present an undesirable appearance. The present inventors extensively studied this problem, and finally found that ~hen a curved surface having a radius of curvature of not more than 5 mm on the rib portion o~ the container is stretched by the gas pressure of the con-tents, delamination occurs with a high probability in a par~ composed of five resin layers, whereas it occurs with a very low probability in a part composed of three resin layers; and that the gas-barrier property of the same amount of the gas-barrier resin is better at the part composed of five layers containing two layers of the gas-barrier resin than at the part composed of three resin layers containing one layer of the gas-barrier resin. This finding has now led to the present inven-tion.
SUMMARY OF THE INVENTION
, _ It is an object of this invention to provide ablow-molded container free from delamination between resin layers.
Another object of this invention is to provide a blow-molded container having excellent gas-barrier property and mechanical property and being free from delamination.
Still another object of this invention is to provide a blow-molded container having excellent gas-barrier property and mechanical strength and being free from occurrence of delamination at a part having a radius of cur~ature of not more than 5 mm in the rib portion of the container.
A further object of this invention is to pro-vide a blow-molded container which does not undergo ~3~
delamination even after it is used for a long period of time as a container for holding potable watee which require gas-barrier proper~y to oxygen and/or carbon dioxide gas.
The objects of this invention are achieved by a biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermo-plastic resin (resin A) other than resin B; wherein the mouth portion is composed of resin A and substantially non-oriented, and the remainder consists of a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately and a portion com-posed of three layers of resin A and two layers of resin B which are laminated with the res.in A layer and the resin B layer occurring alternately.
BRIEF ~ESCRIPTION OF TEiE ACCOMPANYING DRAWINGS
Figures 1, 2 and 3 are partly broken-away front views of examples of the blow-molded container of this inventiOn;
Figure 4 is an enlarged view of a portion encircled in a broken line in Figure l;
Figure 5 is a sectional view taken on line A-A
of Figure 2;
Figure 6 is a sectional view, corresponding to Figuee 5, in which the resin B layer is located on the outside;
Figure 7 is a schematic view of an ex~mple vf an apparatus used to produce the parison in the present invention;
Figures 8 to 10 are sectional views of examples of the parison obtained by the present inYention;
Figures 11 to 14 are sectional views showing the process of forming the parison shown in Figure 8; and 3s Figures 15 to 18 are sectional views showing examples of parisons formed under inappropriate condi tions.
~3~ g DETAILED DBSCRIPTION OF PREFERRED EMBODIMENTS
The present invention will be described by reference to the accompanying drawings.
Figures 1 t 2 and 3 are partly broken-away front views showing examples of the container of the invention.
Figure 1 shows a self-supporting stretch blow-molded bottle. Figure 2 shows a base cup-equipped stretch blow-molded bottle. Figure 3 is a self-supporting stretch blow-molded bottle having ribs existing at the lower part of its body portion.
In the example of Figure 1, the bottle includes a vertical rib 7 as a site having a small radius of curvature at its shoulder portion 4 and a lateral rib 8 as a site having a small radius of curvature at its lS bottom portion S. Hence, the shoulder portion 4 and the bottom portion S are each of a three layer structure composed of two layers o~ resin A and one layer of resin B, and the body portion 6 of the bottle is of a five-layer structure composed of three layers of resin A and two layers of resin B. Figure 4 is an enlarged view of the circular part shown by a broken line in Figure 1 presented in order to clearly show the resin B layer shown by a solid line in Figure 1.
In the example of Yigure 2, the bottle has a vertical rib 9 and a lateral rib 10 as sites having a small radius of curvature at its shoulder portion 4.
Thus, the ~houlder portion is of a three-layer structure composed of two layers of resin A and one layer of resin B, and the body portion 6 and the bottom portion 5 are 3~ each of a five-layer structure composed of three layers of resin A and two Iayers o~ resin B. In Figure 5 which is an enlarged view taken along line A A of Fig~re 2, the left side is the inside of the bottle and the right side is the outside of the bottle~
In the example of Figure 3, the bottle has a lateral rib 7 and a vertical rib 8 as sites having a l3~1b89 small radius of curvature at its body portion 6. Hence, the shoulder portion 4 and the body portion 6 above the lateral rib 7 are of a five-layer structure composed of three layers of resin A and two layers of re in B, and the bottom portion below the lateral rib 7 is of a three-layer structure composed of two layers of resin A
and one layer of resin B.
As shown in Figures 1 to 3, thle opening end part 3 of the mouth portion of the bottl~e and its vicinity are substantially unstretched and composed of resin A. The reason for this i5 that since this part has a small surface area and a large thickness~ it does not so much affect the gas-barrier property of the entire bottle, and that the gas-barrier resin ~resin B) generally has high hygroscopicity, and when not oriented, absorbs water and becomes whitened to present an undesir-able appearance.
When the radius of curvature of the container becomes small and the resin layers of the bottle are stretched under internal pressures during use, an inter-layer shear strain is generated and delamination of the eesin layers tends to occur. The stretch blow-molded container from a parison is for~ed by introducing a high-pressure gas into a heated parison and inflating it 25 f rom inside and pressing it against the mold. Hence, a bent part of the container has a sharp shape of a small radius of curvature faithfully following the shape of the mold as it is near the outside close to the mold. In Figure 6 which is an enlarged view taken along line A-A
in Figure 2, the resin B layer is positioned close to the outside. Since the radius of curvature of the resin B in the the rib portion of the container is smaller than that of the resin B layer in Figure 5, delamination tends to occur in comparison with the case of Figure 6~ Accord-3~ ingly, it is preferred to position the resin B layer nearthe inside as in Figure 5.
~3~
On the other hand, since the gas-barrier resin generally decreases abruptly in gas-barrier property as the humidity approaches 100 %, it is preferred to posi-tion ~he gas-barrier resin layer (re~in B layer) at a part near the outside which is remote from the contents.
In the present invention, there are two gas-barrier layers in that portion of the container which is other than the sites having a small radius of curvature in the rib portion, and one of them is located near the outside.
Accordingly, the reduction of the gas-barrier property is little.
As stated above, th~ blow-molded container of this invention comprises a substantially non-oriented portion of resin A including the opening end of the mouth portion of the container, and the remainder consisting of a portion composed of two layers o resin A and one layer of resin B alternately }aminated and a portion composed of three layers of resin A and two layers of resin B.
The container can be produced by producing a parison having the corresponding layer structure and then bi-axially stretching and blow-molding the parison.
The method of producing the parison will be described.
Figure 7 is a schematic view showlng a device 2S for producing a parison which is a precursor of the container of the invention. This device is provided with a cylinder 12 for resin A (reference numeral 11 and a cylinder 13 for resin B ~refeeence numeral 2) and are connected to a mold 14 at a nozzle portion lS. The resins A and B melted in tbe cylinders 12 and 13 re-spectively are injected simultaneously or alternately into a cavity 18 of the mold 14 via a hot runner portion 16 and a g2te 17.
The parison as a precursor of the container of the invention is formed by properly combining simultane-ous injection and alternate injection of the resins A and 13(~1~8~
B using the above device. This combination differs depending upon the positions at which three layers and fives layers are formed. In the following description, typical examples shown in Figures 8 to 10 will be taken up. In the case of Figure 8 in which three layers, five layers and three layers are formed f rom the opening end part of the mouth portion toward the bottom portion ~3~/3 layers); in the case of Figure 9, three layees and five layers are formed from the opening end part of the mouth portion toward the bottom portion ~3/5 layers); and in the case of Figure 10, five layers and three layers are formed from the opening end part of the mouth portion toward the bottom portion (5/~ layers).
3/5/3 layers lS A parison of the 3/S/3 layer structure is formed by the following procedure.
~ 1) The total amount of resin B to be injected is adjusted to 1 to 2S ~ of the volume of the cavity.
(2) Only resin A is iniected in an amount corresponding to 20 to 70 % of the volume of the cavity (step I).
~ 3~ Resin B in an amount 5 to 35 % of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of resin B to be in-jected are simultaneously injected (step II ) .
(4) Resin B:in an amount 30 to 90 % of thetotal amount of resin B to be injected is injected either alone or together with resin A in an amount not more than two times the amount of resin B injected ~step III).
(S) Resin B in an amount 5 to 35 ~ of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of resin B injected are injected simultaneously (step IV).
~6i Finallyr resin A alone is injected in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity ~step V).
~L3~
g By the above procedure, a parison can be formed.
3~5 layers A parison of the 3/5 layer structure is formed by the following procedure~
tl) The total amount of resin B to be injected is adjusted to 1 to 25 % of the volume of the cavity.
(2) Resin A alone i5 injected in an amount corresponding to 20 to 70 % of the volumle of the cavity (step I).
t3) Resin B in an amount 10 to 70 ~ of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of resin B to be in--jected are simultaneously injected (step II).
~4) Resin B in an amount 30 to 90 ~ of the total amount of resin B to be injected is injected either alone or together with resin A in an amount not more than two times the amount of resin B ~o be injected (step III).
(S) Resin B in an amount 5 to 35 ~ of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of resin B injected are injected simultaneously (step IV).
~6i Finallyr resin A alone is injected in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity ~step V).
~L3~
g By the above procedure, a parison can be formed.
3~5 layers A parison of the 3/5 layer structure is formed by the following procedure~
tl) The total amount of resin B to be injected is adjusted to 1 to 25 % of the volume of the cavity.
(2) Resin A alone i5 injected in an amount corresponding to 20 to 70 % of the volumle of the cavity (step I).
t3) Resin B in an amount 10 to 70 ~ of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of resin B to be in--jected are simultaneously injected (step II).
~4) Resin B in an amount 30 to 90 ~ of the total amount of resin B to be injected is injected either alone or together with resin A in an amount not more than two times the amount of resin B ~o be injected (step III).
(5) Finally, resin A alone is injected in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity tstep V).
This procedure leads to the formation of a parison.
5/3 layers A parison of the 5/3 layer structure is formed by the following procedure.
(1) The total amount of resin B injected is adjusted to 1 to 25 % of the volume of the cavity.
(2) Resin A alone is injected in an amount corresponding to 20 to 70 % of the volume of the cavity ~step I).
(3) Resin B in an amount corresponding to 30 to 90 ~ of the total amount of resin B to be injected is injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected (step III)~
S4) Resin B in an amount corresponding to 10 to 70 % of the total amount of resin B injected and resin A in an amount 1.0 to 10 times the amount of resin B to be injected are injected simultaneously (step IVl.
(5) Finally, resin A alone is injected in an amount corresponding to 10 to 70 % o the volume of the cavity to fill the cavity (step V).
This procedure can form a parison.
Accordingly, if the amount of resin injected in step II in the formation of a paeison of the 3/5~3 layer is increased and step IV is omitted, a parison of the 3~5 layer structure can be obtainedO If step II in the formation of the parison of the 3~5~3 structure is omitted and the amount of resin B injected in step IV is in-creased, a parisQn of the 5/3 layer structure can beobtained.
Various conditions in the above procedures will be described in detail~
The total amount of resin B described in (1) in 2~ each of the procedures corresponds to 1 to 25 %, prefer-ably S to 10 %, of the volume of the mold cavity. If it is less than 1 ~, a layer of resin B is difficult to form and the re~ulting layer is broken here and thereO The effe~t of adding the resin B layer cannot be expected.
If, o~ the other hand, it exceeds 25 %, the resin B layer tends to be distributed deviatingly as shown in ~igure 16. In the deviated part, the boundary line between the resin A la~er and the eesin B layer becomes conspicuous and presents an undesirable appearance.
If the amount of resin A injected in step I is large, the resin B gathers at the bottom portion. If it is small, the resin B layer tends to stretch in the direction of the opening end of the mouth portion.
Accordingly, the amount of resin A to be injected in step I is adjusted to 20 to 70 ~, preferably 40 to 60 ~, of the volume of the cavi~y.
~3~8~
In step II, resins A and B are injected simul-taneously. The amount of resin B to be injected is 5 to 35 ~, preferably 10 to 25 ~, for the formation of the 3/5/3 layers, and 10 to 70 %r preferably 20 to 50 %~ for the formation of the 3/5 layers, both based on the total amount of the resin B to be injected. rrhe amount of resin A to be injected is 1.0 to 10 times~ preferably 1.2 to 2 times, the amount of the cesin B to be injected in step II. If the amount of resin ~ injected is more than this specified limit, the resin B layer becomes too thin.
If it is less than the specified lower limit, the amount of resin B becomes too large and three layers cannot be formed. In such a case, disturbed five layers with outside thin resin B layers tend to form. In the forma-tion of the 5/3 layers, step II does not exist.
In step III, resin B in an amount correspondingto 30 to 90 %, preferably 50 to 80 %, of the total amount of resin B to be injected is injected either alone or together with resin A in an amount not more than 2 times, preferably 0.1 to 0.9 time, the amount of resin B to be injected in step III. If the amount of resin B injected exceeds 90 ~ it is difficult to form three layers~ If it is less than 30 %, the five-layer portion becomes small as shown in Figure 15. When resin B alone is injectedr two resin B layers in the five-layer portion have an equal thickness. When resin A and resin B are simultaneously injected, the resin B layer on the inside of the parison becomes thicker than the resin B layer near the outside of the parison as the amount of resin A
injected simultaneously increases.
In step IV, resins A and B are simultaneously injected. The amount of resin B to be injected is 5 to 35 %, preferably 10 to 25 ~, for the formation of the 3/5/3 layers, and 10 to 70 ~, preferably 20 to 50 %, for the formation of the 5f3 layers r both based on the total amount of resin B to be injected. The amount of resin A
~L3~ 8~
to be 1njected is 1.0 to 10 times, preferably 1.2 to 2 times t the amount of resin B injected in step IV. If the amount of resin A inject d exceeds the above specified limit, the resin B layers become too ~hin. If it is less than the specified limit, the amount of resin B becomes too large and three layers cannot be formed. Disturbed five layers with thin outside resin B layers tend to for~. Step IV does not exist in the case of forming the 3/5 layers.
In step V, only resin A is injected in an amount corresponding to 10 ko 70 ~, preferably 20 to S0 %, of the volume of the cavityO If the amount of resin ~ injected is less than the specified limit, resin B near ~he gate cannot be completely replaced by resin A, and in the next injecting cycle, a mixture of resin A and resin B ~orms. If it is above the specified limit, the amount of resin A injected previously is so small that as shown in Figure 18, the resin B layer is pushed out by resin A injected next and comes out on the surface at the opening end of the mouth portion. Consequently, troubles such as cracking and whitening by water absorption occur.
Generally, higher speeds of injecting the resins are preferred for shortening the cycle time and preventing whitening ascribed to crystallization. If the injection speed is too high, heat is generated owing to shearing and causes decomposition of the resins. This leads to various troubles such as the formation of vola-tile components, silver streak a reduction in the mol-ecular weight which reduces strength. Preferably, the speed of injecting resin A is 1 to 15 cc/sec in each of steps I to IV, and 5 to lS cc/sec in step V, and the speed of injecting resin B is preferably 5 to 70 ccJsec.
The in~ecting speeds of simultaneously injecting resins A
and B are determined by the ratio of the amounts of 3~ injection of resins A ~nd B.
Figures 11 to 14 show the state of flow of the ~L3~ 89 resins in the cavity which chan~es with time in the production of a parison of the 3/5/3 layer structure.
Each of these figures shows the state at the end of the series of the steps I to IY. Dotted lines in Figures 12 to 14 indicate resin A simultaneous}y injected with resin B.
The container of this invention can be produced by biaxially stretching the parison obtained by the above method at a temperature of 70 to 130 C at a stretch ratio of 1 to 4 in the axial direction and 2 to 7 in the circumferential direction and at an area ratio of 5 to 15. The suitable blowing pressure is lO~to 40 kg/cm2, prefecably 20 to 35 kg/cm . The suitable thickness of the container is 200 to 500 microns, preferably 250 to 450 microns.
Examples of resin A used in this invention include thermoplastic polyester resins, polyolefin resins, polycarbonates, polyacrylonitrile~ polyvinyl chloride and polystyrene. The thermoplastic pslyestfer resins are preferred.
Examples of resin B used in this invention, i.e~ the thermoplastic gas-barrier resin, include MX
nylon, a saponification product of ethylene/vinyl acetate copolymer resin, polyacrylonitrile copolymer resin and polyvinylidene chloride resin. MX nylon is preferred.
A combination of MX nylon with a thermoplastic polyester resin, especially polyethylene terephthalate, is especially preferred because it gives excellent transparency, mechanical st~ength, injection-moldability and stretch blow-moldability.
The thermoplastic polyester resins denote polyesters derived from an acid co~ponent at least 80 mole ~, preferably at least 90 mole %, of which consists of terephthalic acid and a gIycol component at least 80 mole %, preferably at least 90 mole ~, of which consists of ethylene glycol. The remai~der of the acid component may comprise, for example, isophthalate, diphenyl ether-4,4-dicarboxylic acid, naphthalene-1,4-(or 2,6)dicarboxy-lic acid, adipic acidr sebacic acid~ decane-l,10-di-carboxylic acid or hexahydroterephthalic acid. The remainder of the glycol component may comprise, ~or example, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, cyclohexanedimethanol, 2,2-bis(4-hydroxyphenyl)propane, and 2,2-bist4-hydroxyethoxy-phenyl~propaneO Polyester resins which also contain a hydroxycarboxylic acid component such as p-hydroxybenzoic acid may also be used.
The suitable intrinsic viscosity of the thermo-plastic polyester resins is at least 0.55, preferably 0.65 to 1.4. If the intrinsic viscosity i5 less than 0.55, it is difficult to obtain a transparent amorphous mul~ilayered parison, and a container formed from the resulting parison has insufficient mechanical strength.
MX nylon denotes a polymer of m-xylyl~nediamine alone or a polymer containing at least 70 mole ~ of structueal units derived from a mixed xylylenediamine containing at least 30 % of p-xylylenediamine and an alpha,omega-aliphatic dicarboxylic acid having 6 to 10 carbon atoms.
Examples of these polymers include homopolymers such as poly(m-xylylehe adipamide~, poly~m-xylylene sebacamide) and poly~m-xylylene suberamide); copolymers such as a m-xylylene~p-xylylene adipamide copolymer, a m-xylylene/p-xylylene pimeramide copolymer and a m-xylylene/p-xylylene azelamide copolymer; and copolymers of the components of the above homopolymers and co-polymers with aliphatic diamines such as hexamethylene-diamine, alicyclic diamines such as piperazine, aromatic diamines such as p-bis(2-aminoethyl)benzene, aromatic dicarboxylic acids such as terephthalic acid, lactams such as epsilon-caprolactam, omega-aminocarboxylic acids such as omega-aminoheptanoic acid, or aromatic amino-8~
carboxylic acids such as p-aminobenzoic acid.
These polymers may include such polymers as nylon 6, nylon 66, nylon 610 and nylon llo These MX nylon resins suitably have a relative viscosity of at least 1.5, preferably 200 to 4Ø
In the present invention, a coloring agent, an ultraviolet absorber, an antistatic agent, an anti-oxidant, a lubricant, a nucleating agent, etc. may be incorporated into one or both of resins A and B in a~ounts which do not impair the object of the invention~
The layer structure of the multilayered con-tainer of this invention conforms to the desired shape of the container. It is free from delamination between resin layers and has excellent gas-barier property~ The process of this invention can easily produce their multi-layered container having the a~oresaid structure.
The following Examples and Comparative ~xamples illustrate the present invention in greater detail.
The various properties shown in these examples were measured by the following methods.
(1) Intrinsic viscosity 1~1 of the polyester resin Measured at a temperature of 30 ~C in a 6:4 (by weight) mixture of phenol and tetrachloroethane.
(2) Relative viscosity [7rel~ of the polyamide resin Measured at a temperature of 25 C using a solution of 1 9 of the resin in 100 ml of 96 % sulfuric acid.
(3) Oxygen permeability Measured by using OXTRAN 100 (made by ~odern Control Inc.) at a temperature of 20 C, an in~ide re-lative humidity of 100 % and an outside relative humidity of 65 %.
(4) Carbon dioxide escaping test Carbonated water ~4 gas volume) was filled in a ~L3~ g container and stoced at a temperature of 22 C and a relative humidity of 60 %. The amount of carbon dioxide gas escaped was meaured by a pressure gauge 12 weeks later. ~he gas volume were calculated from the pressure in accordance with the table of carbon dioxide absorption coefficients.
~5~ Test for delamination due to gas pressure water at 2 to 4 C was put in a container and filled to a predetermined depth. The container was sealed up with a cap having a rubbee septum. The con-tainer was pressurized with nitrogen gas to a pressure of 7 kg/cm2 for 1 minute, and the occurrence of delamination between resin layers was examined.
Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.75 was used as resin A, and poly(m xylylene adipamide) having a relative viscosity of 2~1 was used as resin B. By using the device shown in Figure 7, a parison was formed which had an outside diameter of 30 mm, a length of 120 mm, a thickness of 4 mm, a weight of 50 g and an inner capacity of about 47 cc.
The amounts of resins A and B injected and the injection speed~ were as indicated in Table 1~ The temperature conditions were as follows:-Injection cylinder for resin A: 270 C
Injection cylinder for resin B: 260 C
Resin flow passage within the mold: 270 C
Mold cooling water: 15 ~C
The parison was heated to 95 C by an infrared heater and biaxially stretched blow-molded under a blow pressure of 20 kg~cm -G to produce a container having the shape shown in Figure 1. In the same way, a container having the shape shown in Figure 2 was produced. Both of the containers had a capacity of 1,500 ml, an outside 3~ diameter of 90 mm and a height of 300 mm. The bent portions of the containers were as follows:
13~
F ~ure 1 Vertical rib: depth 1.0 mm, radius of curvature 102 mm Lateral rib: depth 2.0 mm, radius of curvature 1.8 mm Fiyure 2 Vertical rib: depth 1.2 mm, raclius of curvature 1.0 mm Lateral rib: depth 1.75 mm, raclius of curvature 2.0 mm The two containers were subjected to the mea-surement of oxygen permeability, the test for carbon dioxide gas escaping (only the container having the shape shown in Figure 2) and the test for delamination (only the container having the shape shown in Figure 2~. The results were good as shown in Table 2 for Examples 1 1 and 1-2.
Examples 2 to 6 and Comparative Examples l_to 7 In each run, a parison was formed by i~jection molding in the same way as in Example 1 except that the amounts of resins A and B injected and the speeds of injection in steps I to step IV were changed as indicated in Table 1. The parison had:the layer structure shown in Table 1.
The parisons obtained in Examples 2 and 3 and Comparative Examples 1 and 2 were each stretch blow-molded as in Example 1 to produce containers having the shapes shown in Figu res 1 and 2.
Eight types of the containers so obtained were each subjected to the measurement of oxygen permeability, the test for carbon dioxide gas escaping ~only th~ con-tainers having the shape shown in Figure 2~ and the test for delamination tonly the containe rs having the shape shown in Figure 2).
3~ The results are shown in Table 2 for Examples 2-1, 2-2, 3-1 and 3-2, and Comparative Examples }~ 2, 2-1 and 2-2~
:~L3~
In Comparative Example 1-2, the result of the carbon dioxide escaping test was good because the con-tainer had a five-layer structure, but in the delamina~
tion test, delamination occurred at the vertical rib portion in 48 samples out of 50 samples. On the other hand, in Comparative Example 2-2, no delamination oc-curred in the delamination test because the container had a three-layer structure, but the result of the carbon dioxide gas escaping test was not satisfactoryO
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This procedure leads to the formation of a parison.
5/3 layers A parison of the 5/3 layer structure is formed by the following procedure.
(1) The total amount of resin B injected is adjusted to 1 to 25 % of the volume of the cavity.
(2) Resin A alone is injected in an amount corresponding to 20 to 70 % of the volume of the cavity ~step I).
(3) Resin B in an amount corresponding to 30 to 90 ~ of the total amount of resin B to be injected is injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected (step III)~
S4) Resin B in an amount corresponding to 10 to 70 % of the total amount of resin B injected and resin A in an amount 1.0 to 10 times the amount of resin B to be injected are injected simultaneously (step IVl.
(5) Finally, resin A alone is injected in an amount corresponding to 10 to 70 % o the volume of the cavity to fill the cavity (step V).
This procedure can form a parison.
Accordingly, if the amount of resin injected in step II in the formation of a paeison of the 3/5~3 layer is increased and step IV is omitted, a parison of the 3~5 layer structure can be obtainedO If step II in the formation of the parison of the 3~5~3 structure is omitted and the amount of resin B injected in step IV is in-creased, a parisQn of the 5/3 layer structure can beobtained.
Various conditions in the above procedures will be described in detail~
The total amount of resin B described in (1) in 2~ each of the procedures corresponds to 1 to 25 %, prefer-ably S to 10 %, of the volume of the mold cavity. If it is less than 1 ~, a layer of resin B is difficult to form and the re~ulting layer is broken here and thereO The effe~t of adding the resin B layer cannot be expected.
If, o~ the other hand, it exceeds 25 %, the resin B layer tends to be distributed deviatingly as shown in ~igure 16. In the deviated part, the boundary line between the resin A la~er and the eesin B layer becomes conspicuous and presents an undesirable appearance.
If the amount of resin A injected in step I is large, the resin B gathers at the bottom portion. If it is small, the resin B layer tends to stretch in the direction of the opening end of the mouth portion.
Accordingly, the amount of resin A to be injected in step I is adjusted to 20 to 70 ~, preferably 40 to 60 ~, of the volume of the cavi~y.
~3~8~
In step II, resins A and B are injected simul-taneously. The amount of resin B to be injected is 5 to 35 ~, preferably 10 to 25 ~, for the formation of the 3/5/3 layers, and 10 to 70 %r preferably 20 to 50 %~ for the formation of the 3/5 layers, both based on the total amount of the resin B to be injected. rrhe amount of resin A to be injected is 1.0 to 10 times~ preferably 1.2 to 2 times, the amount of the cesin B to be injected in step II. If the amount of resin ~ injected is more than this specified limit, the resin B layer becomes too thin.
If it is less than the specified lower limit, the amount of resin B becomes too large and three layers cannot be formed. In such a case, disturbed five layers with outside thin resin B layers tend to form. In the forma-tion of the 5/3 layers, step II does not exist.
In step III, resin B in an amount correspondingto 30 to 90 %, preferably 50 to 80 %, of the total amount of resin B to be injected is injected either alone or together with resin A in an amount not more than 2 times, preferably 0.1 to 0.9 time, the amount of resin B to be injected in step III. If the amount of resin B injected exceeds 90 ~ it is difficult to form three layers~ If it is less than 30 %, the five-layer portion becomes small as shown in Figure 15. When resin B alone is injectedr two resin B layers in the five-layer portion have an equal thickness. When resin A and resin B are simultaneously injected, the resin B layer on the inside of the parison becomes thicker than the resin B layer near the outside of the parison as the amount of resin A
injected simultaneously increases.
In step IV, resins A and B are simultaneously injected. The amount of resin B to be injected is 5 to 35 %, preferably 10 to 25 ~, for the formation of the 3/5/3 layers, and 10 to 70 ~, preferably 20 to 50 %, for the formation of the 5f3 layers r both based on the total amount of resin B to be injected. The amount of resin A
~L3~ 8~
to be 1njected is 1.0 to 10 times, preferably 1.2 to 2 times t the amount of resin B injected in step IV. If the amount of resin A inject d exceeds the above specified limit, the resin B layers become too ~hin. If it is less than the specified limit, the amount of resin B becomes too large and three layers cannot be formed. Disturbed five layers with thin outside resin B layers tend to for~. Step IV does not exist in the case of forming the 3/5 layers.
In step V, only resin A is injected in an amount corresponding to 10 ko 70 ~, preferably 20 to S0 %, of the volume of the cavityO If the amount of resin ~ injected is less than the specified limit, resin B near ~he gate cannot be completely replaced by resin A, and in the next injecting cycle, a mixture of resin A and resin B ~orms. If it is above the specified limit, the amount of resin A injected previously is so small that as shown in Figure 18, the resin B layer is pushed out by resin A injected next and comes out on the surface at the opening end of the mouth portion. Consequently, troubles such as cracking and whitening by water absorption occur.
Generally, higher speeds of injecting the resins are preferred for shortening the cycle time and preventing whitening ascribed to crystallization. If the injection speed is too high, heat is generated owing to shearing and causes decomposition of the resins. This leads to various troubles such as the formation of vola-tile components, silver streak a reduction in the mol-ecular weight which reduces strength. Preferably, the speed of injecting resin A is 1 to 15 cc/sec in each of steps I to IV, and 5 to lS cc/sec in step V, and the speed of injecting resin B is preferably 5 to 70 ccJsec.
The in~ecting speeds of simultaneously injecting resins A
and B are determined by the ratio of the amounts of 3~ injection of resins A ~nd B.
Figures 11 to 14 show the state of flow of the ~L3~ 89 resins in the cavity which chan~es with time in the production of a parison of the 3/5/3 layer structure.
Each of these figures shows the state at the end of the series of the steps I to IY. Dotted lines in Figures 12 to 14 indicate resin A simultaneous}y injected with resin B.
The container of this invention can be produced by biaxially stretching the parison obtained by the above method at a temperature of 70 to 130 C at a stretch ratio of 1 to 4 in the axial direction and 2 to 7 in the circumferential direction and at an area ratio of 5 to 15. The suitable blowing pressure is lO~to 40 kg/cm2, prefecably 20 to 35 kg/cm . The suitable thickness of the container is 200 to 500 microns, preferably 250 to 450 microns.
Examples of resin A used in this invention include thermoplastic polyester resins, polyolefin resins, polycarbonates, polyacrylonitrile~ polyvinyl chloride and polystyrene. The thermoplastic pslyestfer resins are preferred.
Examples of resin B used in this invention, i.e~ the thermoplastic gas-barrier resin, include MX
nylon, a saponification product of ethylene/vinyl acetate copolymer resin, polyacrylonitrile copolymer resin and polyvinylidene chloride resin. MX nylon is preferred.
A combination of MX nylon with a thermoplastic polyester resin, especially polyethylene terephthalate, is especially preferred because it gives excellent transparency, mechanical st~ength, injection-moldability and stretch blow-moldability.
The thermoplastic polyester resins denote polyesters derived from an acid co~ponent at least 80 mole ~, preferably at least 90 mole %, of which consists of terephthalic acid and a gIycol component at least 80 mole %, preferably at least 90 mole ~, of which consists of ethylene glycol. The remai~der of the acid component may comprise, for example, isophthalate, diphenyl ether-4,4-dicarboxylic acid, naphthalene-1,4-(or 2,6)dicarboxy-lic acid, adipic acidr sebacic acid~ decane-l,10-di-carboxylic acid or hexahydroterephthalic acid. The remainder of the glycol component may comprise, ~or example, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, cyclohexanedimethanol, 2,2-bis(4-hydroxyphenyl)propane, and 2,2-bist4-hydroxyethoxy-phenyl~propaneO Polyester resins which also contain a hydroxycarboxylic acid component such as p-hydroxybenzoic acid may also be used.
The suitable intrinsic viscosity of the thermo-plastic polyester resins is at least 0.55, preferably 0.65 to 1.4. If the intrinsic viscosity i5 less than 0.55, it is difficult to obtain a transparent amorphous mul~ilayered parison, and a container formed from the resulting parison has insufficient mechanical strength.
MX nylon denotes a polymer of m-xylyl~nediamine alone or a polymer containing at least 70 mole ~ of structueal units derived from a mixed xylylenediamine containing at least 30 % of p-xylylenediamine and an alpha,omega-aliphatic dicarboxylic acid having 6 to 10 carbon atoms.
Examples of these polymers include homopolymers such as poly(m-xylylehe adipamide~, poly~m-xylylene sebacamide) and poly~m-xylylene suberamide); copolymers such as a m-xylylene~p-xylylene adipamide copolymer, a m-xylylene/p-xylylene pimeramide copolymer and a m-xylylene/p-xylylene azelamide copolymer; and copolymers of the components of the above homopolymers and co-polymers with aliphatic diamines such as hexamethylene-diamine, alicyclic diamines such as piperazine, aromatic diamines such as p-bis(2-aminoethyl)benzene, aromatic dicarboxylic acids such as terephthalic acid, lactams such as epsilon-caprolactam, omega-aminocarboxylic acids such as omega-aminoheptanoic acid, or aromatic amino-8~
carboxylic acids such as p-aminobenzoic acid.
These polymers may include such polymers as nylon 6, nylon 66, nylon 610 and nylon llo These MX nylon resins suitably have a relative viscosity of at least 1.5, preferably 200 to 4Ø
In the present invention, a coloring agent, an ultraviolet absorber, an antistatic agent, an anti-oxidant, a lubricant, a nucleating agent, etc. may be incorporated into one or both of resins A and B in a~ounts which do not impair the object of the invention~
The layer structure of the multilayered con-tainer of this invention conforms to the desired shape of the container. It is free from delamination between resin layers and has excellent gas-barier property~ The process of this invention can easily produce their multi-layered container having the a~oresaid structure.
The following Examples and Comparative ~xamples illustrate the present invention in greater detail.
The various properties shown in these examples were measured by the following methods.
(1) Intrinsic viscosity 1~1 of the polyester resin Measured at a temperature of 30 ~C in a 6:4 (by weight) mixture of phenol and tetrachloroethane.
(2) Relative viscosity [7rel~ of the polyamide resin Measured at a temperature of 25 C using a solution of 1 9 of the resin in 100 ml of 96 % sulfuric acid.
(3) Oxygen permeability Measured by using OXTRAN 100 (made by ~odern Control Inc.) at a temperature of 20 C, an in~ide re-lative humidity of 100 % and an outside relative humidity of 65 %.
(4) Carbon dioxide escaping test Carbonated water ~4 gas volume) was filled in a ~L3~ g container and stoced at a temperature of 22 C and a relative humidity of 60 %. The amount of carbon dioxide gas escaped was meaured by a pressure gauge 12 weeks later. ~he gas volume were calculated from the pressure in accordance with the table of carbon dioxide absorption coefficients.
~5~ Test for delamination due to gas pressure water at 2 to 4 C was put in a container and filled to a predetermined depth. The container was sealed up with a cap having a rubbee septum. The con-tainer was pressurized with nitrogen gas to a pressure of 7 kg/cm2 for 1 minute, and the occurrence of delamination between resin layers was examined.
Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.75 was used as resin A, and poly(m xylylene adipamide) having a relative viscosity of 2~1 was used as resin B. By using the device shown in Figure 7, a parison was formed which had an outside diameter of 30 mm, a length of 120 mm, a thickness of 4 mm, a weight of 50 g and an inner capacity of about 47 cc.
The amounts of resins A and B injected and the injection speed~ were as indicated in Table 1~ The temperature conditions were as follows:-Injection cylinder for resin A: 270 C
Injection cylinder for resin B: 260 C
Resin flow passage within the mold: 270 C
Mold cooling water: 15 ~C
The parison was heated to 95 C by an infrared heater and biaxially stretched blow-molded under a blow pressure of 20 kg~cm -G to produce a container having the shape shown in Figure 1. In the same way, a container having the shape shown in Figure 2 was produced. Both of the containers had a capacity of 1,500 ml, an outside 3~ diameter of 90 mm and a height of 300 mm. The bent portions of the containers were as follows:
13~
F ~ure 1 Vertical rib: depth 1.0 mm, radius of curvature 102 mm Lateral rib: depth 2.0 mm, radius of curvature 1.8 mm Fiyure 2 Vertical rib: depth 1.2 mm, raclius of curvature 1.0 mm Lateral rib: depth 1.75 mm, raclius of curvature 2.0 mm The two containers were subjected to the mea-surement of oxygen permeability, the test for carbon dioxide gas escaping (only the container having the shape shown in Figure 2) and the test for delamination (only the container having the shape shown in Figure 2~. The results were good as shown in Table 2 for Examples 1 1 and 1-2.
Examples 2 to 6 and Comparative Examples l_to 7 In each run, a parison was formed by i~jection molding in the same way as in Example 1 except that the amounts of resins A and B injected and the speeds of injection in steps I to step IV were changed as indicated in Table 1. The parison had:the layer structure shown in Table 1.
The parisons obtained in Examples 2 and 3 and Comparative Examples 1 and 2 were each stretch blow-molded as in Example 1 to produce containers having the shapes shown in Figu res 1 and 2.
Eight types of the containers so obtained were each subjected to the measurement of oxygen permeability, the test for carbon dioxide gas escaping ~only th~ con-tainers having the shape shown in Figure 2~ and the test for delamination tonly the containe rs having the shape shown in Figure 2).
3~ The results are shown in Table 2 for Examples 2-1, 2-2, 3-1 and 3-2, and Comparative Examples }~ 2, 2-1 and 2-2~
:~L3~
In Comparative Example 1-2, the result of the carbon dioxide escaping test was good because the con-tainer had a five-layer structure, but in the delamina~
tion test, delamination occurred at the vertical rib portion in 48 samples out of 50 samples. On the other hand, in Comparative Example 2-2, no delamination oc-curred in the delamination test because the container had a three-layer structure, but the result of the carbon dioxide gas escaping test was not satisfactoryO
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Claims (18)
1. A biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermoplastic resin (resin A) other than resin B
and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, (2) a portion com-posed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, and (3) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1), (2) and (3) extending in this order toward the bottom of the container.
and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, (2) a portion com-posed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, and (3) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1), (2) and (3) extending in this order toward the bottom of the container.
2. A biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermoplastic resin (resin A) other than resin B
and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately and (2) a portion composed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1) and (2) extending in this order toward the bottom of the container.
and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately and (2) a portion composed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1) and (2) extending in this order toward the bottom of the container.
3. A biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermoplastic resin (resin A) other than resin B
and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, and (2) a por-tion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1) and (2) extending in this order toward the bottom of the container.
and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, and (2) a por-tion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1) and (2) extending in this order toward the bottom of the container.
4. A process for producing a biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermoplastic resin (resin A) other than resin B and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, (2) a portion com-posed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, and (3) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1), (2) and (3) extending in this order toward the bottom of the container;
which comprises injecting resins A and B into a mold cavity to form a parison, and thereafter stretch blow-molding the parison, wherein the parison is formed by adjusting the total amount of resin B to be injected to 1 to 25 % of the volume of the mold cavity, and (a) injecting resin A alone in an amount corres-ponding to 20 to 70 % of the volume of the cavity, (b) simultaneously injecting resin B in an amount corresponding to 5 to 35 % by weight of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of the resin B to be injected in this step, (c) injecting resin B in an amount correspond-ing to 30 to 90 % of the total amount of resin B to be injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected in this step, (d) simultaneously injecting resin B in an amount corresponding to 5 to 35 % of the total amount of resin B injected and resin A in an amount 1.0 to 10 times the amount of resin B to be injected in this step, and (e) finally injecting resin A alone in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity.
which comprises injecting resins A and B into a mold cavity to form a parison, and thereafter stretch blow-molding the parison, wherein the parison is formed by adjusting the total amount of resin B to be injected to 1 to 25 % of the volume of the mold cavity, and (a) injecting resin A alone in an amount corres-ponding to 20 to 70 % of the volume of the cavity, (b) simultaneously injecting resin B in an amount corresponding to 5 to 35 % by weight of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of the resin B to be injected in this step, (c) injecting resin B in an amount correspond-ing to 30 to 90 % of the total amount of resin B to be injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected in this step, (d) simultaneously injecting resin B in an amount corresponding to 5 to 35 % of the total amount of resin B injected and resin A in an amount 1.0 to 10 times the amount of resin B to be injected in this step, and (e) finally injecting resin A alone in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity.
5. A process for producing a biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermoplastic resin (resin A) other than resin B and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately and (2) a portion composed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1) and (2) extending in this order toward the bottom of the container;
which comprises injecting resins A and B into a mold cavity to form a parison, and thereafter stretch blow-molding the parison, wherein the parison is formed by adjusting the total amount of resin B to be injected to 1 to 25 % of the volume of the mold cavity, and (a) injecting resin A alone in an amount corresponding to 20 to 70 % of the volume of the cavity, (b) simultaneously injecting resin B in an amount corresponding to 10to 70 % by weight of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of the resin B to be injected in this step, (c) injecting resin B in an amount correspond-ing to 30 to 90 % of the total amount of resin B to be injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected in this step, (d) finally injecting resin A alone in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity.
which comprises injecting resins A and B into a mold cavity to form a parison, and thereafter stretch blow-molding the parison, wherein the parison is formed by adjusting the total amount of resin B to be injected to 1 to 25 % of the volume of the mold cavity, and (a) injecting resin A alone in an amount corresponding to 20 to 70 % of the volume of the cavity, (b) simultaneously injecting resin B in an amount corresponding to 10to 70 % by weight of the total amount of resin B to be injected and resin A in an amount 1.0 to 10 times the amount of the resin B to be injected in this step, (c) injecting resin B in an amount correspond-ing to 30 to 90 % of the total amount of resin B to be injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected in this step, (d) finally injecting resin A alone in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity.
6. A process for producing a biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and a thermoplastic resin (resin A) other than resin B and comprising a substantially non-oriented mouth portion composed of resin A, and the remainder consisting of (1) a portion composed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, and (2) a portion composed of two layers of resin A and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately, the portions (1) and (2) extending in this order toward the bottom of the container;
which comprises injecting resins A and B into a mold cavity to form a parison, and thereafter stretch blow-molding the parison. wherein the parison is formed by adjusting the total amount of resin B to be injected to 1 to 25 % of the volume of the mold cavity, and (a) injecting resin A alone in an amount corresponding to 20 to 70 % of the volume of the cavity, (b) injecting resin B in an amount correspond-ing to 30 to 90 % of the total amount of resin B to be injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected in this step, (c) simultaneously injecting resin B in an amount corresponding to 10 to 70 % of the total amount of resin B injected and resin A in an amount 1.0 to 10 times the amount of resin B to be injected in this step, and (d) finally injecting resin A alone in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity.
which comprises injecting resins A and B into a mold cavity to form a parison, and thereafter stretch blow-molding the parison. wherein the parison is formed by adjusting the total amount of resin B to be injected to 1 to 25 % of the volume of the mold cavity, and (a) injecting resin A alone in an amount corresponding to 20 to 70 % of the volume of the cavity, (b) injecting resin B in an amount correspond-ing to 30 to 90 % of the total amount of resin B to be injected either alone or together with resin A in an amount not more than 2 times the amount of resin B to be injected in this step, (c) simultaneously injecting resin B in an amount corresponding to 10 to 70 % of the total amount of resin B injected and resin A in an amount 1.0 to 10 times the amount of resin B to be injected in this step, and (d) finally injecting resin A alone in an amount corresponding to 10 to 70 % of the volume of the cavity to fill the cavity.
7. A biaxially oriented blow-molded container composed of a thermoplastic gas-barrier resin (resin B) and thermoplastic resin (resin A) other than resin A, and comprising (a) a substantially non-oriented mouth portion composed of resin A, (b) a biaxially oriented portion composed of three layers of resin A and two layers of resin B which are laminated with the resin A layer and the resin B
layer occurring alternately, and (c) a biaxially oriented bent portion con-taining a rib part having a radius of curvature of not more than 5 mm and being comosed of two layers of resin A
and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately.
layer occurring alternately, and (c) a biaxially oriented bent portion con-taining a rib part having a radius of curvature of not more than 5 mm and being comosed of two layers of resin A
and one layer of resin B which are laminated with the resin A layer and the resin B layer occurring alternately.
8. The container according to claim 1, wherein the container is a bottle having the mouth, a main body, a bottom and a shoulder between the mouth and the main body, the portion (1) is the shoulder and the portion (3) includes the bottom entirely and a lower part of the main body.
9. The container according to claim 8, wherein at least one of the portion (1) and the portion (3) has a site of a small radius of curvature.
10. The container according to claim 9, wherein the site of a small radius of curvature is a vertical or lateral rib.
11. The container according to claim 2, the container is a bottle having the mouth, a main body, a bottom and a shoulder between the mouth and the main body;
the portion (1) is the shoulder;
and the portion (2) is the main body and the bottom of the bottle.
the portion (1) is the shoulder;
and the portion (2) is the main body and the bottom of the bottle.
12. The container according to claim 11, wherein the shoulder has a site of a small radius of curvature.
13. The container according to claim 12, wherein the site of a small radius of curvature is a vertical or lateral rib.
14. The container according to claim 3, wherein the container is a bottle having the mouth, a main body, a bottom and a shoulder between the mouth and the main body; the portion (1) is the shoulder and an upper part of the main body; and the portion (2) is a lower part of the main body and the bottom.
15. The container according to claim 14, wherein the portion (2) has a site of a small radius of curvature.
16. The container according to claim 15, wherein the site of a small radius of curvature is a vertical or lateral rib.
17. The container according to any one of claims 1 to 3 and 7 to 16, wherein:
the resin A is selected from the group consisting of thermoplastic polyester resins, polyolefin resins, polycarbonates, polyacrylonitrile, polyvinyl chloride and polystyrene; and the resin B is selected from the group consisting of MX nylon, a saponification product of ethylene/vinyl acetate copolymer resin, polyacrylonitrile copolymer resin and polyvinyl-idene chloride resin.
the resin A is selected from the group consisting of thermoplastic polyester resins, polyolefin resins, polycarbonates, polyacrylonitrile, polyvinyl chloride and polystyrene; and the resin B is selected from the group consisting of MX nylon, a saponification product of ethylene/vinyl acetate copolymer resin, polyacrylonitrile copolymer resin and polyvinyl-idene chloride resin.
18. The container according to claim 17, wherein:
the resin A is a thermoplastic polyester resin having an intrinsic viscosity of 0.55 to 1.4 and the resin B is nylon derived from an alpha, omega-aliphatic dicarboxylic acid having 6 to 10 carbon atoms and a diamine that is m-xylylenediamine or a mixture of p- and m-xylylenediamines.
the resin A is a thermoplastic polyester resin having an intrinsic viscosity of 0.55 to 1.4 and the resin B is nylon derived from an alpha, omega-aliphatic dicarboxylic acid having 6 to 10 carbon atoms and a diamine that is m-xylylenediamine or a mixture of p- and m-xylylenediamines.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000574081A CA1301089C (en) | 1988-08-08 | 1988-08-08 | Multilayered container and process for production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000574081A CA1301089C (en) | 1988-08-08 | 1988-08-08 | Multilayered container and process for production thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1301089C true CA1301089C (en) | 1992-05-19 |
Family
ID=4138505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000574081A Expired - Lifetime CA1301089C (en) | 1988-08-08 | 1988-08-08 | Multilayered container and process for production thereof |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1301089C (en) |
-
1988
- 1988-08-08 CA CA000574081A patent/CA1301089C/en not_active Expired - Lifetime
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