JP2000015688A - Method for orienting blow molding and transparent oriented blow molded multilayer bottle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for orienting blow molding to manufacture a transparent oriented blow molded multilayer bottle having an excellent transparency, impact resistance, gas barrier properties, heat resistance, low- temperature resistance, ultraviolet absorbability, excellent alkali resistance in the case of alkali cleaning to be executed in the case of recovering from a market, cleaning, refilling and reusing, preservation stability of a content and perfume retentivity required for a bottle or the like for food and the transparent oriented blow molded multilayer bottle. SOLUTION: In the method for manufacturing the transparent oriented blow molded multilayer bottle comprising the step of orienting blow molding a preform having (A) an outer layer made of a polycarbonate resin and (B) an inner layer made of a polyethylene naphthalate resin, a thickness of the polycarbonate resin layer of the preform is 0.5 to 30 mm, and a thickness of the polyethylene naphthalate resin layer is 0.5 to 6 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polycarbonate resin having excellent impact resistance and alkali resistance as well as excellent moldability and storage stability of the contents, without impairing transparency which is an excellent feature of the polycarbonate resin. The present invention relates to a stretch blow molding method for producing a transparent stretch blow-molded multilayer bottle comprising a layer and a polyethylene naphthalate resin layer, and a transparent stretch blow-molded multilayer bottle.

[0002]

2. Description of the Related Art Conventionally, various plastics have been used as materials for containers such as seasonings, oils, juices, carbonated drinks, beer, sake, cosmetics, and detergents. As the material, various plastics are employed according to the kind of the filling content and the purpose of use. Among these plastic materials, polyethylene terephthalate or polyethylene naphthalate is used for its mechanical strength, heat resistance, and transparency. Because of its excellent properties and gas barrier properties, it is used as a material for containers for juices, soft drinks, carbonated drinks, seasonings, detergents, cosmetics, and the like. Among these uses, hollow molded containers for filling juices, soft drinks, and carbonated drinks are required to be sterilized and filled at a high temperature. Therefore, heat-resistant resins that can withstand high-temperature filling are required. It is required to form a hollow molded container,
In addition, all of these hollow molding containers for filling are transparent,
In addition, it is required to have excellent shape stability such as small variation in the internal volume.

[0003] JP-A-2-217222 proposes a bottle made of polyethylene naphthalate resin which is highly stretched. However, bottles made of polyethylene naphthalate resin are improved in terms of impact resistance, as they may be shocked during transportation while filled with juice, etc., or if they are accidentally dropped during handling, causing delamination. Is required.

[0004] On the other hand, polycarbonate resins are used as large bottles for foodstuffs because they are superior to polyethylene terephthalate resins in terms of impact resistance and because they have excellent transparency and heat resistance. However, it shows relatively high permeability to gases such as water vapor, oxygen and carbon dioxide. That is, it is inferior to a gas barrier. As a means for improving the gas permeability, a method of laminating a material having a low gas permeability, that is, a gas barrier material, on a polycarbonate resin layer has been proposed. JP-A-61-222741 discloses a multilayer structure comprising a polycarbonate resin layer, an olefin vinyl alcohol copolymer layer, and a polyolefin layer, and a bonding layer of each layer comprising a binder selected from an olefin vinyl ester copolymer and a modified polyolefin copolymer. Has been proposed. JP-A-60-179
No. 255 proposes a multilayer hollow polycarbonate container comprising an inner layer of a polycarbonate resin layer, an intermediate layer of polyalkylene terephthalate or the like, and an outer layer of the polycarbonate resin layer. JP-A-61-270155 proposes a laminated structure composed of a polycarbonate resin layer, a layer of a carboxylic acid-modified ethylene-α-olefin random copolymer, and a layer composed of a saponified olefin-vinyl acetate copolymer. Have been. JP-A-62-4
No. 6644 proposes a laminate of a specific copolymer layer containing vinyl acetate as a main component and another thermoplastic resin. The laminated materials proposed in these publications have disadvantages such as poor heat resistance and insufficient solvent resistance.

Further, Japanese Patent Application Laid-Open No. 5-124094 proposes a transparent multi-layer bottle comprising a polyester resin layer and a polycarbonate resin layer having a Tg of 135 ° C. or less. In Japanese Patent Application Laid-Open Publication No. H11-157, a stretch blow-molded article comprising a polycarbonate resin layer, a polyester resin layer and a polycarbonate resin layer is proposed, but in this case, the solvent resistance is insufficient.

For the purpose of improving both of these drawbacks, ie, heat resistance and solvent resistance, Japanese Patent Application Laid-Open No. 7-101028 discloses a multilayer structure comprising an aromatic polycarbonate resin layer and a polyalkylene naphthalate resin layer. It is described that the appearance of the obtained bottle is good. In the examples, an extruder for an outer layer having a built-in full-flight screw having a diameter of 65 mm and an extruder for an inner layer having a built-in full-flight screw having a diameter of 40 mm were used.
The temperature was set to 80 ° C. and 270 ° C., and a two-layer die was used. The outer layer was 50 μm in an aromatic polycarbonate resin layer, and the inner layer was 50 μm in polyethylene naphthalate (intrinsic viscosity IV = 0.6 dl / g) as a polyalkylene naphthalate resin layer. A two-layer, two-layer multilayer bottle is illustrated by laminating as much as possible.

Although this bottle is effective for soft drink bottles and the like because of its configuration, it can be estimated that it is particularly useful for squeeze bottles such as tomato ketchup and mayonnaise bottles.

On the other hand, a stretch blow molding method has attracted attention as a method for obtaining a large bottle molded product at low cost. Stretch blow molding refers to a molding method in which a preform is previously molded by injection molding, and then the preform is heated and then blown by blowing air while stretching the preform with a stretching rod.

The stretch blow molding method is superior to the conventional extrusion blow molding method in dimensional accuracy, particularly in the accuracy of the plug, so that gas barrier properties can be enhanced.
The appearance is also better than the conventional extrusion blow molding method.
Furthermore, in the conventional extrusion blow molding method, since the parison is sandwiched by the mold and blow molded, burrs are generated along the parting line of the mold, and cracks are easily generated from the parting line due to a drop impact or the like. On the other hand, the stretch blow molding method does not cause the above-described problem, and thus has features such as excellent impact resistance.

In the case of stretch blow molding, there is a step of heating and cooling the resin, particularly at the time of forming the preform. Particularly, the inner layer resin receives an extra heat history at the time of molding the outer layer resin. Furthermore, since a preform heating step is also required, when polyethylene naphthalate is used for the inner layer, whitening due to crystallization of polyethylene naphthalate is likely to occur, and a transparent stretch blow-molded product has not been easily obtained.

In general, in order to obtain a large bottle molded product having a uniform thickness by the stretch blow molding method, it is necessary that the drawdown due to its own weight when heating the preform is small, and that there is no swelling without uneven thickness when blowing. Is required for the material. However, the polycarbonate resin has a large drawdown due to its own weight at the time of heating the preform, and also has a large thickness unevenness at the time of blowing, so that it is difficult to obtain a uniform thick molded product, especially in the case of a large bottle molded product, molding is difficult. .

[0012] Recently, in order to improve the drawdown due to its own weight when heating the preform from the molding apparatus surface and the swelling property at the time of blowing, Japanese Patent Application Laid-Open No. Hei 8-164557 discloses a first molding die in which the injection step of the preform is performed. And the second molding die, the inner layer is injection molded by the first molding die, the outer layer is injection molded by the second molding die, and the heating of the preform is performed inside and outside the preform. There has been proposed a method for molding a polycarbonate container, wherein the method is performed by radiant heat from a heating member provided in the container.

[0013]

SUMMARY OF THE INVENTION The object of the present invention is to provide transparency, impact resistance, gas barrier property, heat resistance, cold resistance, ultraviolet absorption, recovery from the market, washing, and the like required for food bottles and the like. A stretch blow molding method and a transparent stretch blow molded multilayer bottle for producing a transparent stretch blow molded multilayer bottle excellent in alkali resistance to alkali washing performed when refilling and reused, storage stability of contents and excellent scent retention. To provide.

The inventor of the present invention has conducted intensive studies on the method of producing the transparent stretch blow-molded multilayer bottle in order to obtain the transparent stretch blow-molded multilayer bottle. As a result, the preform for obtaining the bottle was made of a polycarbonate resin layer having a specific thickness and a polyethylene naphthalate resin. It has been found that a multilayered bottle can be easily obtained by forming a layer in accordance with a wide range of processing conditions, and the present invention has been completed.

[0015]

According to the present invention, a transparent stretch blow-molded multilayer bottle is produced by stretch-blow molding a preform having (A) an outer layer made of a polycarbonate resin and (B) an inner layer made of a polyethylene naphthalate resin. A stretch blow molding method and a transparent stretch blow, wherein the thickness of the polycarbonate resin layer of the preform is 0.5 mm to 30 mm and the thickness of the polyethylene naphthalate resin layer is 0.5 mm to 6 mm. It relates to a molded multilayer bottle.

The transparent stretch blow-molded multilayer bottle provided by the present invention comprises an outer layer made of a polycarbonate resin and an inner layer made of a polyethylene naphthalate resin.

The polycarbonate resin used in the present invention is a resin usually used as an engineering resin, and is obtained by reacting a dihydric phenol with a carbonate precursor in a solvent (interfacial polymerization method) or in a molten state (ester exchange method). The resulting polycarbonate resin.

A typical example of the dihydric phenol used here is 2,2-bis (4-hydroxyphenyl)
Propane (commonly called bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4- Hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, bis (4- (Hydroxyphenyl) ether, 4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) sulfite, bis (4-hydroxyphenyl) sulfone, and the like. Preferred dihydric phenols are bis (4-hydrodiphenyl) alkanes, of which bisphenol A is particularly preferred.

In producing the polycarbonate resin by reacting the above-mentioned dihydric phenol with the carbonate precursor, the dihydric phenol may be used alone or in combination of two or more, and the polycarbonate resin may be a trifunctional or higher polyfunctional aromatic compound. It may be a branched polycarbonate resin obtained by copolymerizing a group III compound or a mixture of two or more polycarbonate resins. Further, if necessary, a catalyst, a molecular weight regulator and an antioxidant may be used.

The basic means for producing this polycarbonate resin will be briefly described. In the case of a solvent method (interfacial polymerization method) using phosgene as a carbonate precursor, the reaction is usually performed in the presence of an acid binder and a solvent.
Examples of the acid binder include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide and amine compounds such as pyridine. As the solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. For promoting the reaction, a catalyst such as a tertiary amine or a quaternary ammonium salt may be used. As the molecular weight regulator, for example, phenol or p-te
It is desirable to use a terminal terminator such as an alkyl-substituted phenol such as rt-butylphenol and 4- (2-phenylisopropyl) phenol. During the process. At that time, the reaction temperature is usually 0 to
40 ° C. and the reaction time is a few minutes to 5 hours. The pH during the reaction is preferably maintained at 10 or higher. It is not necessary that all of the resulting molecular chain ends have a structure derived from the terminator.

In the transesterification reaction (melting method) using a carbonic acid diester as a carbonate precursor, a predetermined ratio of a dihydric phenol component and, if necessary, a branching agent and the like are stirred while heating with the carbonic acid diester in an inert gas atmosphere. This is carried out by a method of distilling off alcohols or phenols produced. The reaction temperature varies depending on the boiling point of the alcohol or phenol to be formed, etc.
The range is from 0 to 300 ° C. The reaction is completed under reduced pressure from the beginning while distilling off alcohol or phenols produced. Further, a catalyst which is currently used in a transesterification reaction to promote the reaction can also be used. As the carbonic acid diester used in the transesterification reaction, for example, diphenyl carbonate,
Dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate,
Dibutyl carbonate and the like. Of these, diphenyl carbonate is particularly preferred. It is also preferable to add diphenyl carbonate, methyl (2-phenyloxycarbonyloxy) benzene carboxylate, or the like as a terminal terminator at the initial stage of the reaction or at an intermediate stage of the reaction.

The molecular weight of the polycarbonate resin is generally represented by a viscosity average molecular weight of 10,000 to 40,000,
Preferably it is 15,000-35,000. The viscosity average molecular weight (M) in the present invention is 100 ml of methylene chloride.
The specific viscosity (ηsp) obtained from a solution of 0.7 g of a polycarbonate resin dissolved at 20 ° C. was inserted into the following equation.

Ηsp / C = [η] + 0.45 × [η] ²
C [η] = 1.23 × 10 ⁻⁴ M ^0.83 (where [η] is the intrinsic viscosity and C is the polymer concentration of 0.7.) The structural viscosity index of the polycarbonate resin used in the present invention is usually While the structural viscosity index N of the polycarbonate resin used for melt molding of N is N = 1.2 to 1.3, it is preferably N = 1.4 to 8, and more preferably N = 1. 0.6 to 3.

The structural viscosity index N is expressed by the following formula: Q = K · p ^{N where} Q is the fluidity (ml / sec) of the molten resin, K is a constant, and p is the pressure (kg / kg).
cm ² ), and N is determined from the structural viscosity index]. N = 1
In the case of, Newtonian flow behavior is exhibited, and as N increases, non-Newtonian behavior is exhibited. The structural viscosity index that can be molded under general molding conditions is at most 10.

As a polycarbonate resin having a structural viscosity index N = 1.4 to 8, a viscosity average molecular weight of 10,000 or less is used.
A polycarbonate resin consisting only of a branched polycarbonate resin obtained by copolymerizing a branching agent having a molecular weight of from 00 to 40,000;
Such a branched polycarbonate resin and a viscosity average molecular weight of 1
A polycarbonate resin containing a linear polycarbonate resin having a viscosity of 000 to 40,000, a linear ultra-high molecular weight polycarbonate resin having a viscosity average molecular weight of 70,000 to 200,000 and a viscosity average molecular weight of 10,000 to 3
A polycarbonate resin having a viscosity average molecular weight of 10,000 to 40,000 blended with a linear polycarbonate resin having a viscosity average molecular weight of 70,000 to 20;
A viscosity average molecular weight of 10,000 obtained by blending a linear ultra high molecular weight polycarbonate resin having a viscosity of 10,000 and a branched polycarbonate resin having a viscosity average molecular weight of 10,000 to 30,000.
Polycarbonate resins of 000 to 40,000 can also be suitably used if the structural viscosity index N is N = 1.4 to 8. Here, the linear polycarbonate resin refers to a polycarbonate resin produced without substantially incorporating a branching agent.

More specific examples of the polycarbonate resin having a structural viscosity index N = 1.4 to 8 are as follows: 100 parts by weight of a linear polycarbonate resin having a viscosity average molecular weight of 10,000 to 30,000; Viscosity average molecular weight 70,
000-200,000 ultra high molecular weight polycarbonate resin and / or viscosity average molecular weight 10,000-40,
A polycarbonate resin obtained by mixing 5 to 25 parts by weight of a 2,000 branched polycarbonate resin can be preferably used. The viscosity average molecular weight of such a polycarbonate resin is measured by the method described above.

The constituent components of the ultrahigh molecular weight polycarbonate resin are those having a viscosity average molecular weight of 10,000 to 30,000.
May be different from the components of the linear polycarbonate resin, but are preferably the same.

The linear ultrahigh molecular weight polycarbonate resin has a viscosity average molecular weight of 70,000 to 200,0.
In the case where 00 is used, the structure viscosity index can be efficiently improved, and at the same time, the melt viscosity is not unnecessarily increased.

In producing the branched polycarbonate resin, for example, at least one kind of trifunctional or higher polyfunctional compound as shown in the following examples is used as a branching agent, and 0.05 to 3 based on the total polyhydric phenol. It is produced by a method of copolymerizing 0.0 mol%. Here, all polyhydric phenols refer to the sum of dihydric phenols and trifunctional or higher polyfunctional compounds. Examples of branching agents include, for example, phloroglucin, phloroglucid, or 4,6-dimethyl-2,4,
6-tris (4-hydrodiphenyl) heptene-2,
2,4,6-trimethyl-2,4,6-tris (4-hydroxyphenyl) heptane, 1,3,5-tris (4
-Hydroxyphenyl) benzene, 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-dimethyl-4-hydroxyphenyl) ethane, 2,6-bis (2- (Hydroxy-5-methylbenzyl) -4-methylphenol, 4- {4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene}-
Trisphenol such as α, α-dimethylbenzylphenol, tetra (4-hydroxyphenyl) methane, bis (2,4-dihydroxyphenyl) ketone, 1,4-bis (4,4-dihydroxytriphenylmethyl) benzene, or Trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and acid chlorides thereof, and the like, include 1,1,1-tris (4-hydroxyphenyl) ethane, 1,1,1-tris (3,5-dimethyl) −
4-Hydroxyphenyl) ethane is preferred, especially 1,
1,1-Tris (4-hydroxyphenyl) ethane is preferred. The molecular weight of this branched polycarbonate resin is
In general, it is represented by a viscosity average molecular weight of 1 as described above.
0000-40,000, preferably 15,000-
30,000.

When the viscosity average molecular weight of the branched polycarbonate resin is from 10,000 to 40,000, the structural viscosity index can be efficiently increased, and the melt viscosity is not unnecessarily increased.

By mixing a branched polycarbonate resin obtained by such a production method with a straight-chain polycarbonate resin not copolymerized with a branching agent, a branched polycarbonate resin satisfying such a branching agent concentration and molecular weight is obtained. May be adjusted. That is, when the linear polycarbonate resin is mixed with the branched polycarbonate resin, the concentration of the branching agent is 0.05 to 3 mol% based on the entire polyhydric phenol, and the viscosity average molecular weight is 10,000.
0-40,000, preferably 15,000-30,0
00.

The polyethylene naphthalate resin constituting the transparent stretch blow-molded multilayer bottle of the present invention is a polyester containing naphthalenedicarboxylic acid as a main acid component and ethylene glycol as a main glycol component.

In the present invention, “naphthalenedicarboxylic acid” refers to, for example, 2,6 naphthalenedicarboxylic acid,
The main target is 2,7-naphthalenedicarboxylic acid and its ester-forming derivative, but a part thereof (30 mol%
Less than) other dicarboxylic acids, such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, also terephthalic acid,
Aromatic dicarboxylic acids such as isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, diphenylether-4,4'-dicarboxylic acid And alicyclic dicarboxylic acids such as hexahydroterephthalic acid, decalin dicarboxylic acid, and teleralin dicarboxylic acid, and oxyacids such as glycolic acid and p-oxybenzoic acid. Examples of the ester-forming derivative of the acid component include lower alkyl esters, phenyl esters, and acid anhydrides.

The term "glycol component" mainly refers to ethylene glycol, and part (less than 30 mol%) of other glycols, such as tetramethylene glycol, propylene glycol, 1,3-butanediol and neoglycol. Aliphatic diols such as pentyl glycol,
Alicyclic diols such as cyclohexane dimethanol and tricyclodecane dimethylol, bisphenol A,
An aromatic diol such as bisphenol S, bishydroxyethoxybisphenol A, or tetrabromobisphenol A may be used. Also, as in ordinary polyesters, heat stabilizers such as phosphorus compounds, antioxidants such as hindered phenol, ultraviolet absorbers such as benzotriazole, hydroxybenzophenone, cyanoacrylate, titanium oxide, carbon black, terazole blue, etc. Even if a nucleating agent such as a pigment, a dye, or talc, a crystallization accelerator such as a higher fatty acid salt, or a release agent is added, there is no problem.

Further, in the present invention, an amount in a substantially linear range, for example, an amount of 2 mol% or less based on the total acid components,
Also included are those obtained by copolymerizing a polycarboxylic acid or a polyhydroxy compound having three or more functional groups, such as trimellitic acid and pentaerythritol.

The polyethylene naphthalate of the present invention can be produced by a conventional polyester production method. Among them, transesterification is carried out in the presence of a transesterification catalyst such as Mg compound, Ca compound, P compound, Ge compound and Sb compound. It is preferable to produce the compound by reacting a lower alkyl ester of naphthalenedicarboxylic acid with ethylene glycol. In this reaction, a part (for example, 20 mol% or less) of the lower alkyl ester of naphthalenedicarboxylic acid is mixed with another acid component. It may be substituted, or a part of the glycol (for example, 20 mol% or less) may be substituted with another glycol component.

Examples of the lower alkyl ester of naphthalenedicarboxylic acid include dimethyl ester, diethyl ester, dipropyl ester and the like, and dimethyl ester is particularly preferred.

The polyethylene naphthalate resin is substantially linear, which is confirmed by the dissolution of the polyethylene naphthalate in o-chlorophenol.

The intrinsic viscosity [η] of polyethylene naphthalate measured in o-chlorophenol at 25 ° C. is 0.3
-0.9 dl / g, preferably 0.4-0.8 dl / g
g, more preferably 0.6 to 0.8 dl / g, and most preferably 0.62 to 0.68 dl / g.

The intrinsic viscosity [η] of polyethylene naphthalate is measured by the following method. That is, polyethylene naphthalate is converted to o-chlorophenol by 1
g / 100 ml and melt viscosity is measured at 25 ° C. using an Uperode capillary viscometer.
-Chlorophenol is gradually added, the melt viscosity on the lower concentration side is measured, and the intrinsic viscosity ([η]) is extrapolated to 0% concentration.
Ask for.

The limiting viscosity index is 0.3 to 0.9 dl /
By setting to g, the fluidity during molding, that is, the moldability and the mechanical properties of the molded article can be satisfied at the same time, and a suitable alkali resistance can be maintained.

The thickness of the polycarbonate resin layer constituting the preform is 0.5 mm to 30 mm, preferably 1 mm to 20 mm. If the thickness is less than 0.5 mm, the shape retention of the preform becomes insufficient during heating in the heating pot, and the uniformity of the thickness of the obtained blow molded product becomes insufficient. In molding the reform, it takes a long molding time and also requires a long time for heating in a heating pot, so that the polyethylene naphthalate layer is undesirably whitened due to crystallization.

On the other hand, the thickness of the polyethylene naphthalate resin layer is 0.5 mm to 6 mm, preferably 1 mm
５5 mm. If the thickness is less than 0.5 mm, the fluidity of the polyethylene naphthalate resin will be insufficient, and it will be difficult to mold a preform. On the other hand, if it exceeds 6 mm, the preform which has been crystallized and whitened due to the crystallization of polyethylene naphthalate when the preform is molded, when heated again, it is necessary to apply excessive heat to completely melt the crystal, As the cycle becomes longer, the polycarbonate layer is heated more than necessary, and the whole preform has a disadvantage of being easily deformed. Further, when the heating is performed to avoid such a problem, the melting of the crystals is incomplete, so that there is a disadvantage that the transparency, which is an excellent feature of polycarbonate, is reduced. Here, the thickness of the polycarbonate resin layer and the thickness of the polyethylene naphthalate resin layer in the preform refer to the thickness substantially at the center of the preform body.

The stretch blow-molding method of the present invention adopts the above-described structure to provide a transparent stretch blow-molded multilayer having excellent impact resistance and alkali resistance without impairing transparency, which is an excellent feature of a polycarbonate resin. The bottle is what you achieve.

In the present invention, the thickness of the polycarbonate resin layer is 0.07 to 10 mm, the thickness of the polyethylene naphthalate resin layer is 10 to 2000 μm, the total light transmittance is 20% or more, and the haze is 50% or less. A transparent stretch blow-molded multilayer bottle can be achieved. Such a bottle sufficiently satisfies the transparency which is the main object of the present invention, and at the same time, has sufficient strength and alkali resistance as a bottle,
It satisfies the gas barrier properties and ultraviolet absorption.

More preferably, the thickness of the polycarbonate resin layer is 0.07 to 5 mm, particularly preferably 0.1 to 5 mm.
1 to 5 mm. The thickness of the polyethylene naphthalate resin layer is preferably 30 to 1500 µm, particularly preferably 60 to 1500 µm. Further, regarding the transparency, the total light transmittance is 50% or more and the haze is 30% or less, and particularly preferably, the total light transmittance is 70% or more and the haze is 10% or less.

The thickness of each layer of the transparent stretch blow-molded multilayer bottle referred to in the present invention refers to the thickness of the bottle body, and is generally thicker at the plug and the bottom corner than at the body. The thickness of the transparent stretch blow-molded multilayer bottle of the present invention is preferably 140 μm or more, more preferably 150 μm to 10 mm, and still more preferably 200 μm to
5 mm. In particular, in the case of a large water bottle having an inner volume of 5 liters or more, high impact resistance is required for repeated use, and 1 to 5 mm is preferable.

The transparent stretch blow-molded multilayer bottle of the present invention is formed of at least two layers of a polycarbonate resin layer and a polyethylene naphthalate resin layer. Adhesive layer such as modified polyolefin,
A hot melt layer or the like may be interposed. Further, a thermoplastic resin layer such as a polyester resin such as polyethylene naphthalate resin, an acrylic resin, a polyolefin resin such as polyethylene or polypropylene, or a thermoplastic resin layer such as a polyamide resin is further provided on the outside of the polycarbonate resin layer of the stretch blow-molded bottle with a heat-shrinkable tube. It may be provided by a shrink film or the like, or a hard coat layer or a printing layer for preventing abrasion may be provided.

One of the objectives of the present invention to provide a polyethylene naphthalate resin on the inner surface of a transparent stretch blow-molded multi-layer bottle, that is, on the side that comes into contact with the bottle filling, is that the bottle containing the contents is resistant to dropping during handling. This is because damage such as delamination does not occur even when subjected to an impact. A second object is to prevent various impurities present in the polycarbonate resin layer from being eluted into the contents of the bottle. Since polyethylene naphthalate resin has a dense molecular space as compared with polycarbonate resin, these impurities hardly pass through the inside of the resin molecule. As impurities in such a polycarbonate resin, an interfacial polymerization method,
That is, in a polycarbonate resin produced by an emulsion polymerization method, the solvent used (methylene chloride, chlorobenzene, n
-Hexane, etc.), and unreacted starting materials such as dihydric phenol (especially bisphenol A), reaction products (Na ions, chloride ions, etc.), tertiary amines as catalysts, and terminal stoppers (phenol, t -Butylphenol, cumylphenol) and low molecular weight reactants having a molecular weight of 3,000 or less in terms of styrene. In the case of a polycarbonate resin obtained by a transesterification method (melt method), unreacted dihydric phenol (especially bisphenol A) and carbonic acid diester (especially diphenyl carbonate), phenol as a reaction product, and various residues as a residue of a reaction catalyst and a deactivator are used. Metal ions such as sodium ion, potassium ion, calcium ion, antimony ion, titanium ion, zinc ion, ammonium ion, quaternary ammonium ion, tertiary amine ion, etc., and anion ion (chlorine ion, nitrate ion, etc.) ), T-butyl phenol, cumyl phenol, phenyl-2-methoxyphenyl carbonate as a terminal stopper, and the above-mentioned low molecular weight.

In the polycarbonate resin obtained by the interfacial polymerization method and the transesterification method, it is important to prevent phenols, such as unreacted bisphenol A, from being eluted among the impurities, which change the taste of foodstuffs in the bottle. Such unreacted bisphenol A is conventionally 30 ppm
When the composition of the present invention is contained, the elution of bisphenol A can be almost prevented, but preferably,
20 ppm to below the detection limit in liquid chromatography, more preferably 1 ppm
A polycarbonate resin containing bisphenol A from 0 ppm to the detection limit or less, most preferably 1 ppm to the detection limit or less is desirable. In the polycarbonate resin of the interfacial polymerization method, most of the solvent to be used is methylene chloride, and this methylene chloride has conventionally been contained in an amount of 30 ppm or more, and the elution of this solvent can be almost prevented by the constitution of the present invention. 10 ppm of methylene
Below the detection limit, more preferably from 5 ppm to below the detection limit,
Most preferably, a polycarbonate resin containing from 1 ppm to the detection limit or less is preferable.

A third object is to maintain the durability of the bottles collected from the market for alkali washing performed for reuse. This alkali washing is usually performed at an alkali concentration of 1 to 4% by weight, a temperature of 60 to 80 ° C., and a washing time of 2 to 7 minutes.
Since the conditions are severe, stress cracks occur and accelerate. On the other hand, polyethylene naphthalate resin has a high alkali resistance, so that phenomena such as generation of cracks and increase in haze are not observed even if it is repeatedly used for washing several tens of times. The transparent stretch blow-molded multilayer bottle of the present invention having such a resin on the inner surface is excellent in alkali washing resistance,
There is almost no decrease in transparency.

In the production of the transparent stretch blow-molded multi-layer bottle of the present invention, generally, the resin constituting each layer is injected by using several injection molding machines to form a preform, and this preform is further blow-molded. A way to be taken. Examples of the blow molding method include a one-stage method in which a preform in a molten state is blow-molded in a blow mold, and a two-stage method in which preform molding and blow molding are performed in separate steps.

In any of the layers forming the transparent stretch blow-molded multilayer bottle of the present invention, an ultraviolet absorber, an antistatic agent,
Coloring agents, antibacterial agents, heat stabilizers, especially phosphites such as triphenyl phosphite which suppresses transesterification between the polycarbonate resin and the polyethylene naphthalate resin may be added within a range not to impair the purpose of the present invention. it can.

The transparent stretch blow-molded multilayer bottle of the present invention is used for dairy products such as milk, yogurt, lactic acid bacteria drinks and milk drinks, soft drink bottles such as taste drinks, carbonated drinks and fruit drinks, and drinks. 5 to 40 liter water bottles for storing water, liquor bottles such as sake, beer and wine, oils and fats bottles, soy sauce, sauces, liquid bottles such as vinegar, etc., dairy product bottles, soft drink bottles, water Suitable for bottles, more preferably dairy bottles, water bottles, most preferably water bottles.

[0055]

EXAMPLES The present invention will be further described below with reference to examples. In addition,
Parts and% in the examples are parts by weight and% by weight. The stretch blow moldability was measured by the following method after forming a preform with a molding machine.

(1) Structural Viscosity Index The dried polycarbonate resin pellets were put into a cylinder (pore diameter 1 mm, length 10 mm) of a Koka type flow tester (CFT-500, Shimadzu Corporation), and the temperature was set to 28.
The pressure P (100, 120, 1) was kept constant at 0 ° C.
40, 160, and 180 kgf / cm ² ) and the flow rate Q (ml / sec) of each molten resin is measured by the following formula, and each value is obtained from the slope of a regression line obtained by plotting each value on a log-log graph. Q = K · P ^N (log Q = ^N log P + 1 log K) Q: Outflow (m1 / sec) P: Pressure (kg / cm ² ) N: Structural viscosity index K: Constant

(2) Transparency The total light transmittance was measured according to ASTM D1003. The total light transmittance is preferably 20% or more, and the haze is preferably 50% or less.

(3) Alkali Washing Resistance The bottles of Examples and Comparative Examples were repeatedly immersed in a 3% by weight aqueous solution of NaOH at 60 ° C. for 7 minutes five times, and the appearance and transparency of the bottles were visually determined. ：: No change at all. ×: Haze increased or cracks occurred at several places.

(4) Impact resistance A stretch blow-molded multilayer bottle having an internal volume of 20 liters is formed, and the stretch blow-molded multilayer bottle is filled with 20 liters of water and sealed so that water does not leak from the plug. And dropped freely from a height of 4.5 m. This operation was repeated three times, and the presence or absence of cracks was visually determined. The drop test was performed on five bottle samples. The criteria are as follows. ：: No crack. Δ: Although not broken, the deformation is remarkable, pinholes are generated, and water leaks. X: Cracking.

(5) Drawdown Property When a preform molded by a molding machine is heated, the amount of sag due to its own weight after heating is measured.

(6) Swelling property at the time of blowing The thickness of a stretch blow-molded multi-layer bottle having an inner volume of 20 liters obtained by blowing blow air into a preform and measuring the maximum thickness and the minimum thickness is measured. The difference was obtained, and the swelling property at the time of blowing was evaluated.

Examples 1 to 5 and Comparative Examples 1 to 4 In Examples and Comparative Examples, the resin of each layer shown in Table 1 was obtained by first injection-molding the inner layer and double-injecting the outer layer on the outside. Using the obtained test tubular preform having a length of 30 cm, a transparent stretch blow-molded multilayer bottle was then formed by a stretch blow molding method. The outer diameter of the inner layer was constant at 9 cm, and the inner diameter changed according to the thickness. On the other hand, the inner diameter of the outer layer was constant at 9 cm, and the outer diameter changed according to the thickness. Resin temperature 320 ° C, mold temperature 1
First, the inner layer was injection-molded at 10 ° C., and the outer layer was double-injected on the outer side. The preform immediately after molding is put into a heating pot having a rod-shaped heater as an inner heating member and a ring-shaped heater as an outer heating member, and the temperature of the heating member is 310 ° C. for both the inside and the outside.
For 15 seconds, and immediately after the blow pressure of 5 kgf / c
Blow molding was performed under the conditions of m ² to form a narrow-mouth stretch blow-molded multilayer bottle having a length of about 40 cm. The meaning of each component symbol in Table 1 is as follows. (A) Polycarbonate resin (PC) PC-A1: Viscosity average molecular weight of 20,000 synthesized by an interfacial polymerization method from bisphenol A and phosgene PC-A2: Synthesized by an interfacial polymerization method from bisphenol A and phosgene PC-UM: Ultra-high molecular weight aromatic polycarbonate resin having a viscosity average molecular weight of 120,000 synthesized by an interfacial polymerization method from bisphenol A and phosgene PC-M: Bisphenol A And 1,1, as a branching agent
By subjecting 1-tris (4-hydroxyphenyl) ethane to transesterification with diphenyl carbonate in a total of 100 mol% of the branching agent and bisphenol A, 0.3 mol% of the branching agent was copolymerized. Molecular weight 24,
500 aromatic polycarbonate resin PEN: polyethylene naphthalate resin with intrinsic viscosity [η] = 0.65 (manufactured by Teijin Limited)

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[Table 1]

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[Table 2]

As is clear from these tables, comparing Example of the present invention and Comparative Example 2, the bottle obtained by the production method satisfying the conditions of the present invention has high transparency and furthermore, the content is preserved. Excellent in alkali resistance, alkali washing resistance, impact resistance, and swelling during blowing. On the other hand, when the polyethylene naphthalate layer is thick and does not satisfy the conditions of the present invention, it is understood that transparency is lacking and a good bottle cannot be obtained.

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According to the stretch blow molding method of the present invention, the impact resistance, without impairing the excellent transparency of polycarbonate resin, which is difficult with conventional polycarbonate resin bottles or polyethylene naphthalate bottles alone, can be obtained. Excellent alkali resistance, gas barrier properties, fragrance retention,
Transparent stretching consisting of an outer layer made of polycarbonate resin and an inner layer made of polyethylene naphthalate resin, which have good heat resistance, cold resistance, and storage stability of the contents, and also have excellent plug accuracy and excellent impact resistance. This is a method for producing a blow-molded multilayer bottle, and the obtained bottle is an extremely excellent one satisfying the above-mentioned properties. The transparent stretch blow-molded multilayer bottle of the present invention is useful for dairy product bottles, soft drink bottles, and water bottles, particularly suitable for water bottles, and its production method and industrial utility value of the bottle are extremely large.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B65D 1/09 B65D 1/00 B // B29K 67:00 B29L 22:00 F term (reference) 3E033 AA01 BA18 BA26 BB04 BB08 CA03 CA07 CA13 CA16 CA18 CA20 FA03 GA02 4F100 AK42B AK45A BA02 BA07 BA10A BA10B EH36 EJ21 EJ37 GB16 GB23 JA06A JB07 JD02 JD09 JJ03 JJ04 JK10 JN01 JN08 YY00 YY00A YY00B 4F208 AA26 AA28 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA26 AA28 AA26 AA26 AA26 AA26 AA26 AA26 AA26

Claims (4)

[Claims] 1. A method for producing a transparent stretch blow-molded multilayer bottle by stretch blow molding a preform having (A) an outer layer made of a polycarbonate resin and (B) an inner layer made of a polyethylene naphthalate resin. 0.5mm thickness of polycarbonate resin layer
A stretch blow molding method, wherein the thickness is 30 mm and the thickness of the polyethylene naphthalate resin layer is 0.5 mm to 6 mm. 2. The structural viscosity index N of a polycarbonate resin.
The stretch blow molding method according to claim 1, wherein N = 1.4 to 8. 3. A stretch blow molded multilayer bottle having (a) an outer layer made of a polycarbonate resin and (b) an inner layer made of a polyethylene naphthalate resin, wherein the thickness of the polycarbonate resin layer is 0.07 to 10 mm, The thickness of the phthalate resin layer is 10 to 2000 μm, the total light transmittance is 20% or more, and the haze is 50
% Or less. 4. The transparent stretch blow-molded multilayer bottle according to claim 3, wherein the transparent stretch blow-molded multilayer bottle is one selected from a dairy product bottle, a soft drink bottle, and a water bottle.