JP5807461B2 - Injection molded product with excellent transparency and method for producing the same - Google Patents

Description

  The present invention relates to an injection-molded article made of a polyester resin and a method for producing the same, and more specifically, imparts heat resistance without subjecting a heat-resistant stretch-molded container excellent in transparency and stretch balance to heat fixation. The present invention relates to an injection-molded article that is possible and excellent in transparency and a method for producing the same.

Stretch-molded containers of thermoplastic polyester resins such as polyethylene terephthalate have excellent transparency and surface gloss, as well as impact resistance, rigidity, and gas barrier properties required for containers such as bottles and cups. It is used as a container for beverages and foods.
However, stretch-molded containers made of polyester resin have the disadvantage of poor heat resistance and cause heat deformation and volume shrinkage deformation when the contents are hot filled, so the biaxial stretch blow container is set to a high temperature after molding In general, an operation of heat setting (heat setting) with a molded mold is performed.

Further, when the stretch-molded container is molded by the one-stage blow molding method, the stretch-molded container having a small residual strain and excellent heat resistance is formed by heating and stretching the preform at a high temperature. Can be molded.
For example, in the one-stage blow molding method, the preform temperature is set as high as possible, and further, heat generation due to internal friction or heat generation due to crystallization at the time of stretching at a high speed is used, and stretch molding and heat setting are simultaneously performed, A method for obtaining a stretch blow bottle made of a polyester resin having high heat resistance has been proposed (Patent Document 1).

  When stretching at a high temperature, the strain hardening phenomenon is unlikely to occur. Therefore, unless the stretching speed is made extremely high, stretching does not propagate to the entire molded product, and a stretch molded container having a uniform thickness cannot be obtained. For this reason, in the past, when the mechanical stretching speed was limited, the stretching temperature was lowered and the stretching balance was obtained at the expense of heat resistance, which is the merit of high-temperature stretching. Even in stretch blow molding under high temperature conditions, in order to provide a stretch-molded container made of a polyester resin having a good stretch balance by strain hardening regardless of the stretch speed, a continuous phase made of an ethylene terephthalate polyester resin and an inorganic substance In addition, a stretch-molded container having a dispersion structure composed of a dispersion composed of the above and having at least a tan δ maximum value and a tan δ maximum temperature in a dynamic viscoelasticity measurement value of the container body portion is proposed (Patent Document 2).

Japanese Patent No. 1767894 JP 2008-217921 A

The heat setting performed to impart heat resistance to the stretch-molded container is generally a temperature equal to or higher than the melting point of monomers such as monohydroxyethyl terephthalate (MHET) and bishydroxyethyl terephthalate (BHET) contained in the polyester, These monomers are precipitated by heat fixation, and this monomer becomes a pressure-sensitive adhesive so that the oligomer adheres to the mold, etc., which necessitates frequent cleaning of the mold and decreases the productivity, or the container This caused the problem that the transparency of the film deteriorated.
In addition, in order to achieve a sufficient stretch balance by strain hardening under high-temperature conditions as described above, in stretch-molded containers containing inorganic substances, even in stretch blow molding under high-temperature conditions, regardless of the stretch speed, It has a good stretch balance due to strain hardening and excellent heat resistance, but there is a limit to fine dispersion of inorganic materials in a well-balanced polyester, and there is an inorganic material with a refractive index different from that of polyester. Therefore, there is a problem that transparency is impaired.

In order to solve such a problem, the present inventors blended a polyester resin with a chain extender, and in the polyester resin, produced a polymer having a long-chain branched structure having the polyester resin as a branch component, When the polyester resin around the polymer component having such a long-chain branched structure is locally overstretched, the local overstretching contributes effectively to necking propagation, and high-speed stretching is performed under high temperature conditions It was found that the same stretching balance (uniformity of the wall thickness distribution) was expressed (Japanese Patent Application No. 2010-66181).
A stretch-molded body made of a polyester resin blended with such a chain extender has excellent transparency and excellent heat resistance even if it is not subjected to heat fixation, but the reaction rate is greatly branched. When forming a preform by injection molding, which tends to gel and increase the crystallization speed due to the formation of a polymer, and which tends to cause molecular orientation, whitening of the injection molded product itself occurs, or the preform It has been found that there is a problem that whitening due to heating tends to occur during the stretching process.

Accordingly, an object of the present invention is to provide an injection molded product made of a polyester resin blended with a chain extender and capable of forming a stretch molded container having excellent transparency. .
Another object of the present invention is to provide a production method capable of forming an injection-molded product capable of forming a heat-resistant stretch-molded container excellent in transparency and stretch balance with high productivity and economy. .

According to the present invention, it comprises an ethylene terephthalate polyester resin (A) and a chain extender (B) having a functional group reactive with the terminal functional group of the polyester resin (A), and the weight average molecular weight Mw is 3 An injection-molded article comprising a resin composition containing 1.0 × 10 ⁵ or more of a high molecular weight component in an amount of 1.0% by weight or more, the ethylene terephthalate polyester resin (A) being added to the polyester resin (A The terminal functional group blocking agent (C) composed of a carbodiimide compound with respect to the terminal functional group of) is blended at a concentration of 100 to 15000 ppm, and the chain extender (B) is an epoxy having a weight average epoxy functional group number of 4 or more. A modified styrene / (meth) acrylic copolymer, which is contained at a concentration of 10 to 4000 ppm, and has the following formula: ΔTc1 = 2ndTc1 − 1stTc1
In the formula, 2ndTc1 is a crystallization exothermic peak measured with a differential scanning calorimeter for a sample which has been rapidly melted after heating and melting for 5 minutes, and 1stTc1 represents a crystallization exothermic peak measured with a differential scanning calorimeter for the sample before melting. ,
An injection molded product is provided in which the value of ΔTc1 represented by the formula is 20 ° C. or less.

According to the present invention, there is also provided a stretch-molded container having a layer composed of an ethylene terephthalate-based polyester resin, which is obtained by biaxial stretch blow molding of the injection molded product.

Further according to the present invention, the terminal functional group sealing agent (C) for the terminal functional group of the polyester resin (A) is blended with the ethylene terephthalate-based polyester resin (A), and then the terminal functional group of the polyester resin (A). By blending a chain extender (B) having a functional group having reactivity with a group and melt-kneading, 1.0% by weight or more of a high molecular weight component having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more is obtained. A resin composition containing the above-mentioned amount is prepared, and the resin composition is injection-molded to produce an injection-molded article, the ethylene terephthalate-based polyester resin (A) having a terminal functional group of the polyester resin (A). A terminal functional group blocking agent (C) composed of a carbodiimide compound with respect to the group is blended at a concentration of 100 to 15000 ppm, and the chain extender (B) is a weight average epoxy functional group. There is an epoxy-modified styrene (meth) acrylic copolymer is 4 or more, a manufacturing method of an injection molded article, characterized in that it is contained in a concentration of 10 to 4000ppm is provided.

The injection-molded product of the present invention has an improved crystallization rate by suppressing the occurrence of gelation by optimizing the addition conditions of the chain extender and modifying the polyester resin used. Therefore, whitening of the injection-molded product itself is prevented, and it is possible to provide a stretch-molded container excellent in transparency without being whitened by heating in secondary processing such as stretch molding. In addition, the polymer having a long-chain branch structure formed by blending a chain extender is the same as the raw material of the PET resin, which is the main raw material, and therefore has an approximate refractive index and is a stretch-molded product with excellent transparency. Can be provided.
In addition, the stretch-molded container obtained by stretch-molding the injection-molded product of the present invention has excellent stretch balance and stable thickness distribution, so that it has excellent mechanical strength such as buckling strength and undulation. Appearance abnormalities such as water and sink marks are sufficiently suppressed.
Furthermore, the stretch-molded container formed by stretch-molding the injection-molded product of the present invention can form a stretch-molded container having excellent heat resistance without performing heat-setting, so that mold contamination caused by heat-setting occurs. Therefore, there is no problem that the transparency of the mold is reduced due to frequent cleaning of the mold and mold contamination, and the energy required for heat fixation can be reduced.
In addition, using a general-purpose polyethylene terephthalate resin, which is less expensive than a heat-resistant polyester resin, a container having excellent heat resistance can be provided, and the productivity and economy are excellent.

In the method for producing an injection-molded product of the present invention, the weight average molecular weight Mw is 3.0 × 10 ⁵ or more so as not to cause whitening of the injection-molded product by blending a terminal functional group blocking agent. It is possible to easily control the production of the high molecular weight component.
Furthermore, by adding a terminal functional group capping agent to the polyester resin together with the chain extender, it is possible to suppress an increase in the crystallization rate that occurs when the chain extender is blended. A polyester resin having a low intrinsic viscosity can be used, and higher heat resistance can be imparted.

The schematic diagram of the external appearance of the sheet | seat with a favorable extending | stretching balance after biaxial stretching shaping | molding is shown. The schematic diagram of the external appearance of a sheet | seat with a bad stretch balance after biaxial stretching is shown. The schematic which shows an example of the screw structure of the twin-screw extruder used in the Example is shown. The schematic for demonstrating another example of the screw structure of the twin-screw extruder used in the Example is shown. The stretch blow bottle created in the Example is shown.

The injection-molded article of the present invention comprises an ethylene terephthalate-based polyester resin (hereinafter sometimes referred to as “PET resin”) (A) and a chain having a functional group reactive with the terminal functional group of the PET resin (A). A high molecular weight component comprising an extender (B) and having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more is 1.0% by weight or more, preferably 1.0 to 20% by weight, more preferably 1.0 to 10%. The first characteristic is that the resin composition is contained in an amount of% by weight, and the second characteristic is that the value of ΔTc1 represented by the above formula (1) is 20 ° C. or less.
The PET resin that is the base resin of the injection-molded product of the present invention is generally a linear polymer having a weight average molecular weight in the range of 50,000 to 100,000. By adding a chain extender to the PET resin, In the resin, a polymer having a long-chain branched structure containing a PET resin as a branch component is produced. Among polymers having a long-chain branched structure using such a PET resin as a branch component, a high-molecular component having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more is distorted compared to a linear polymer. Since the relaxation time is longer, the viscosity is higher than that of the PET resin as the base resin, and it is difficult to be deformed by stretching as compared with the PET resin. Only the local overstretching, and this local overstretching contributes effectively to necking propagation and develops the same stretch balance (uniform thickness distribution) as when high-speed stretching under high temperature conditions. It becomes possible to do.
In addition, when the amount of the high molecular weight component having the weight average molecular weight Mw of 3.0 × 10 ⁵ or more is less than 1.0% by weight, sufficient stretching balance cannot be improved, but on the other hand If it is too large, it is inferior in injection moldability, which is not preferable.

  In addition, if the reaction between the PET resin and the chain extender proceeds excessively, gelation of the resin occurs and it becomes easy to form molecular orientation. When the resin is used, the crystallization speed increases and the injection molded product is whitened. However, in the injection molded product of the present invention, the addition condition of the chain extender is optimized and the end function of the PET resin is increased. By adding a terminal functional group blocking agent to the group, excessive reaction between the PET resin and the chain extender is suppressed, and the value of ΔTc1 represented by the above formula (1) is maintained at 20 ° C. or less. Such a problem does not occur.

  That is, as expressed by the above equation (1), the crystallization exothermic peak temperature 1stTc1 by the differential scanning calorimeter (DSC) of the injection molded product and the differential scanning calorimeter (after the sample cut out from the injection molded product is melted and rapidly cooled) The difference ΔTc1 of the crystallization exothermic peak temperature 2ndTc1 by DSC) is 20 ° C. or less, that is, these values are close to each other, which means that the crystallization speed of the injection molded product is reduced. Thus, it is possible to provide a stretch-molded product which is formed with good stretch moldability and has excellent stretch balance (thickness uniformity) and transparency without whitening or stretch inhibition due to crystallization. When measuring ΔTc1 in a stretched molded product, the differential scanning calorific value is obtained by cutting a sample from the vicinity of the mouth or bottom center in the case of a stretch blow bottle, for example, in the case of a stretch blow bottle due to the characteristics of the molding method. Measure the meter (DSC).

  Further, the melting treatment at the time of measuring the crystallization exothermic peak temperature 2ndTc1 is performed at a temperature T equal to or higher than the melting point of the PET resin to be used, specifically Tm + 10 ≦ T ≦ Tm + 40, while the rapid cooling treatment is specifically performed. Is performed at a temperature-decreasing rate of 130 ° C./min or higher up to 20 ° C. The value of ΔTc1 (° C.) represented by the above formula (1) is preferably greater than 0 and not greater than 20 ° C., particularly preferably in the range of 0 to 10 ° C. When it is greater than 20 ° C., it will be described later. As is clear from the results of the examples, the crystallization rate becomes excessively high and there is a risk of whitening by heating.

It is also apparent from the results of Examples described later that the injection molded product of the present invention having such characteristics can provide a stretched molded product having excellent transparency and stretch balance.
That is, it consists of a PET resin (A) and a chain extender (B) having a functional group reactive with the terminal functional group of this PET resin (A), and the weight average molecular weight Mw is 3.0 × 10 ⁵ or more. An injection molded product comprising a resin composition containing a high molecular weight component in an amount of 1.0% by weight or more and having a value of ΔTc1 represented by the above formula (1) of 20 ° C. or less has a haze. In addition to being excellent in transparency of 2.2% or less, the stretching balance is also excellent (Examples 1 to 5).
On the other hand, it consists of a PET resin (A) and a chain extender (B) having a functional group reactive with the terminal functional group of this PET resin (A), and the weight average molecular weight Mw is 3.0 × 10. ^It consists of a resin composition containing ⁵ or more high molecular weight components in an amount of 1.0% by weight or more. When ΔTc1 represented by the above formula (1) is larger than 20 ° C., the transparency is inferior. Further, crystallization proceeds excessively during heating, and stretch molding cannot be performed (Comparative Examples 1, 3, 4, and 5). Further, ΔTc1 represented by the above formula (1) is 20 ° C. or less, but from a resin composition containing a high molecular weight component having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more in an amount of less than 1.0% by weight. In this case, it is clear that only a molded product having excellent transparency but poor stretching balance can be obtained (Comparative Example 2).

In the present invention, in an injection molded article comprising a polyester resin composition comprising a PET resin (A) and a chain extender (B), the resin composition has a weight average molecular weight Mw of 3.0 × 10 ⁵ or more. In order to make the value of ΔTc1 represented by the above formula (1) not more than 20 ° C., the reaction between the PET resin and the chain extender It is necessary to control that the crystallization proceeds excessively and the crystallization rate increases, and various methods can be adopted as long as the crystallization rate can be controlled.
For example, methods to slow the progress of the reaction, such as lowering the reaction temperature, shortening the residence time, adding the chain extender in small portions, stirring and kneading quickly after adding the chain extender, and increasing the shear rate Thus, the crystallization rate can be controlled by a technique such as destroying the long-chain polymer component.
Preferably, a terminal functional group sealing agent (C) for the terminal functional group of the PET resin is blended with the PET resin (A), and then a functional group having reactivity with the terminal functional group of the PET resin (A) is added. A resin composition containing a high molecular weight component having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more in an amount of 1.0% by weight or more is prepared by blending the chain extender (B) having the melt and kneading. It is particularly desirable to prepare and use this. As is apparent from the results of the examples described later, it is apparent that stretched molded articles having excellent transparency and stretch balance can be provided (Examples 1 to 4 and Comparative Example 4).

(Ethylene terephthalate polyester resin)
In the ethylene terephthalate polyester resin used for molding the injection-molded article of the present invention, the dicarboxylic acid component is 50% or more of the dicarboxylic acid component, particularly 80% or more is terephthalic acid, and the diol component is 50% of the diol component. In particular, a polyester resin in which 80% or more is ethylene glycol is used. Such an ethylene terephthalate-based polyester resin satisfies mechanical properties, thermal properties, and molding processability in a well-balanced manner among polyester resins.

Of course, it can also contain carboxylic acid components other than terephthalic acid. Examples of carboxylic acid components other than terephthalic acid include isophthalic acid, naphthalenedicarboxylic acid, p-β-oxyethoxybenzoic acid, and biphenyl-4,4′-dicarboxylic acid. , Diphenoxyethane-4,4′-dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, adipic acid, sebacic acid and the like.
As the diol component, 50% or more, particularly 80% or more of the diol component is preferably ethylene glycol in view of mechanical properties and thermal properties. As diol components other than ethylene glycol, 1,4-butanediol, Examples include propylene glycol, neopentyl glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, cyclohexane dimethanol, ethylene oxide adduct of bisphenol A, glycerol, and trimethylolpropane.

  Further, the dicarboxylic acid component and the diol component may contain a tribasic or higher polybasic acid and a polyhydric alcohol. For example, trimellitic acid, pyromellitic acid, hemimellitic acid, 1,1,2,2 -Ethanetetracarboxylic acid, 1,1,2-ethanetricarboxylic acid, 1,3,5-pentanetricarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, biphenyl-3,4,3 ', 4 Polybasic acids such as' -tetracarboxylic acid and polyvalent acids such as pentaerythritol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, sorbitol, 1,1,4,4-tetrakis (hydroxymethyl) cyclohexane Mention may be made of alcohol.

The ethylene terephthalate-based polyester resin used in the present invention has a weight ratio of 1: 1 phenol / tetrachloroethane mixed solvent and an intrinsic viscosity (IV) measured at 30 ° C. of 0.60 to 1.00 dL / g, particularly The range of 0.70 to 0.86 dL / g is desirable.
Further, in order to suitably impart heat resistance to the stretching container, it is desirable to use an ethylene terephthalate polyester resin having an intrinsic viscosity in the range of 0.60 to 0.80 dL / g.
Furthermore, as described above, even when an ethylene terephthalate polyester resin having a low molecular weight such as a melt-polymerized resin or a recycled resin is used, it is possible to impart good processability and excellent heat resistance.

(Chain extender)
As the chain extender used in the present invention, any conventionally known chain extender can be used as long as it is a chain extender (B) having a functional group having reactivity with the terminal functional group of the ethylene terephthalate polyester resin (A). it can.
Examples of the chain extender functional group having reactivity with the terminal functional group of the polyester resin and chain extension include an epoxy group, a carbodiimide group, and an isocyanate group.
Epoxy group-containing compounds that can be used as chain extenders include glycidyl methacrylate, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, Glycidyl ether compounds such as polypropylene glycol diglycidyl ether, glycidyl methacrylate, glycerin dimethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, polypropylene Glycoldi Tacrylate, polypropylene glycol diacrylate, polytetramethylene glycol dimethacrylate, polytetramethylene glycol diacrylate, poly (ethylene glycol-tetramethylene glycol) dimethacrylate, poly (ethylene glycol-tetramethylene glycol) diacrylate, poly (propylene glycol- Examples include glycidyl esters such as tetramethylene glycol) dimethacrylate, poly (propylene glycol-tetramethylene glycol) diacrylate, polyethylene glycol-polypropylene glycol dimethacrylate, and polyethylene glycol-polypropylene glycol diacrylate.

  Examples of the carbodiimide-containing compound include diphenylcarbodiimide, di-cyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, dioctyldecylcarbodiimide, diisopropylcarbodiimide, N, N'-di-p-aminophenylcarbodiimide, N, N'- Dioctyldecylcarbodiimide, N, N′-di-2,6-dimethylphenylcarbodiimide, N, N′-di-2,6-diisopropylphenylcarbodiimide, 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide, N , N′-di-p-hydroxyphenylcarbodiimide, N, N′-di-cyclohexylcarbodiimide, N, N′benzylcarbodiimide, N, N′-di-p-ethylphenylcarbodiimide, N, N′-di -O- Sopropylphenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6- Examples thereof include isopropylphenyl carbodiimide, N, N′-di-2,4,6-trimethylphenyl carbodiimide, N, N′-di-2-isobutyl-6-isopropylphenyl carbodiimide, and the like.

As the isocyanate group-containing compound, an aromatic diisocyanate having 6 to 20 carbon atoms (excluding carbon in the NCO group, the same shall apply hereinafter), an aliphatic diisocyanate having 2 to 18 carbon atoms, an alicyclic diisocyanate having 4 to 15 carbon atoms, C8-15 aromatic aliphatic diisocyanates, modified products of these diisocyanates, and mixtures of two or more thereof can be used. Specific examples of the isocyanate group-containing compound include phenylene diisocyanate, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthylene diisocyanate, ethylene diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate ( XDI), lysine triisocyanate and the like.
In addition to the above chain extenders, oxazoline compounds, phenyl carbonate compounds or phenyl ester compounds, lactam compounds, aromatic tetracarboxylic acid anhydrides, and the like can be given.

In the present invention, since it is particularly desirable to use a chain extender excellent in hygiene, among the chain extenders, at least one epoxy-functional (meth) acrylic monomer and at least one non-chain extender are used. Epoxy-modified styrene / (meth) acrylic copolymers formed from functional (meth) acrylic monomers and / or styrene monomers, or carbodiimide compounds can be suitably used.
Examples of epoxy-functional (meth) acrylic monomers used in the epoxy-modified styrene / (meth) acrylic copolymer include both acrylic acid esters and methacrylic acid esters. Specific examples of these monomers include , Monomers containing 1,2-epoxy groups such as glycidyl acrylate and glycidyl methacrylate.
Nonfunctional (meth) acrylic acid monomers include (meth) acrylic acid esters, specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate. , I-propyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, (meth) acryl N-amyl acid, i-amyl (meth) acrylate, isobornyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth ) N-octyl acrylate, n-decyl (meth) acrylate, methyl cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate (Meth) cyclohexyl acrylate is mentioned.
Non-functional styrene monomers can include styrene, α-methyl styrene, vinyl toluene, p-methyl styrene, t-butyl styrene, o-chloro styrene, vinyl pyridine, and mixtures of these species.

In the present invention, the epoxy-modified styrene / (meth) acrylic copolymer having a weight average epoxy functional group number (Mw / epoxy equivalent) of 4 or more, particularly 4 to 15 can be preferably used. The weight average molecular weight is preferably in the range of 4000 to 15000, and the epoxy equivalent is preferably in the range of 200 to 450 g / mol.
Examples of such a chain extender include, but are not limited to, Joncryl ADR 4370S, 4368F / S, 4368C / CS, 4300 (manufactured by BASF).

(End functional group sealant)
In the injection-molded article of the present invention, the reactivity of the terminal functional group of the PET resin, particularly the carboxyl group, is controlled for the purpose of preventing an increase in the crystallization rate of the resin composition comprising the above-mentioned PET resin and chain extender. It is preferable to blend a terminal functional group sealing agent having a sealing action.
As the terminal functional group sealing agent, a conventionally known one can be used as long as it can seal the terminal functional group of the polyester resin, but is not limited thereto, but N, N-2,6- Carbodiimide compounds including monocarbodiimide and polycarbodiimide compounds such as diisopropylphenylcarbodiimide, N, N'-dicyclohexylcarbodiimide, N, N'-diisopropylcarbodiimide, N-ethyl-N '-(3-dimethylaminopropyl) -carbodiimide 2,2′-m-phenylenebis (2-oxazoline), 2,2′-p-phenylenebis (2-oxazoline), 2-phenyl-2-oxazoline, styrene / isopropenyl-2-oxazoline, etc. Compound; 2-methoxy-5,6-dihydro-4H-1,3-oxadi Oxazine compounds such as; N- glycidylphthalimide, cyclohexene oxide, tris (2,3-epoxypropyl) and epoxy compounds such as isocyanurates.
In the present invention, a terminal functional group capping agent composed of a carbodiimide compound can be suitably used in terms of being hygienic and having high reactivity and not high molecular weight. The carbodiimide compound may be any of aromatic, alicyclic and aliphatic. Specifically, LA-1 (Nisshinbo Co., Ltd.) etc. can be used.
Moreover, a terminal functional group sealing agent can also be used in combination of 2 or more type.

(Resin composition)
In the injection-molded article of the present invention, a resin composition comprising a PET resin (A), a chain extender (B) having a functional group reactive with the terminal functional group of the PET resin, and the resin composition It is important that the product is prepared so that a high molecular weight component having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more is 1.0% by weight or more, and further contains a terminal functional group blocking agent (C) In this case, it is desirable to blend the terminal functional group blocking agent (C) into the PET resin (A), and then blend the chain extender (B), and melt knead.
In the present invention, the chain extender (B) is preferably blended in a very small amount of 10 to 4000 ppm, particularly 100 to 1000 ppm in the resin composition. That is, in the present invention, since the extensional viscosity in stretch molding is extremely sensitive to relaxation for a long time, the presence of a small amount of a polymer component having a long-chain branched structure that is generated by adding a very small amount of a chain extender. This makes it possible to obtain a great effect.
The terminal functional group sealing agent (C) is preferably contained in the resin composition at a concentration of 100 to 15000 ppm, particularly 100 to 5000 ppm.

In the present invention, when the terminal functional group sealing agent (C) is used, the PET resin (A) and the terminal functional group sealing agent (C) are put into an extruder and melt kneaded, and then downstream of the same extruder. It is preferable to add a chain extender (B) on the side, and further melt mix to produce a masterbatch, which is blended with a PET resin.
The melt mixing in the masterbatch preparation is performed at a temperature of 180 to 320 ° C., and after performing melt kneading of the PET resin (A) and the terminal functional group sealant (C) for 1 second to 30 minutes, although not limited thereto, It is preferable to add a chain extender and knead for 1 second to 30 minutes.
Further, when the terminal functional group sealing agent (C) is not used, the PET resin (A) is put into an extruder and melt-kneaded, and then the chain extender (B) is added downstream of the same extruder. Thereafter, molding conditions such as screw configuration, rotation speed, discharge amount, and the like are applied so that the chain extender (B) is quickly stirred and kneaded and diffused, and further melt-mixed to produce a master batch. It is preferable to mix | blend with resin.

(Injection molded product)
The injection-molded article of the present invention comprises the above-described PET resin (A) and a chain extender (B) having a functional group having reactivity with the terminal functional group of the PET resin, and the weight average molecular weight Mw is 3.0 ×. As long as a resin composition containing 1.0 ⁵ % or more of a high molecular weight component of 105 or more is used, it can be molded by conventionally known injection molding.
Examples of such injection molded products include various conventionally known molded products such as sheets, films, cups, trays, preforms and bottles.
The injection-molded article of the present invention comprises the above-described PET resin (A) and chain extender (B), and contains 1.0% by weight or more of a high molecular weight component having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more. The resin composition may have at least one layer composed of the resin composition, and may have a single-layer structure of the resin composition, or a multilayer structure in which another thermoplastic resin layer is combined with the layer composed of the resin composition It can also be. In the case of a multilayer structure, it is particularly preferable that the aforementioned PET resin constitutes the inner and outer layers.

  As the thermoplastic resin other than the above-mentioned PET resin, any resin that can be stretch blow molded can be used, and is not limited thereto, but is not limited to this, and olefin resins such as ethylene-vinyl alcohol copolymer and cyclic olefin polymer. And a polyamide resin such as a xylylene group-containing polyamide. Also, an oxygen-absorbing gas barrier resin composition in which a xylene group-containing polyamide is mixed with a diene compound and a transition metal catalyst, recycled polyester (PCR (resin that recycles used bottles), SCR (resin generated in a production plant) ) Or a mixture thereof) or the like. These recycled polyester resins preferably have an intrinsic viscosity (IV) measured by the method described above in the range of 0.65 to 0.75 dL / g.

Moreover, in order to adhere | attach an inner layer or an outer layer, and an intermediate | middle layer, adhesive resin can also be interposed. As the adhesive resin, an acid-modified olefin resin or polyester resin obtained by graft polymerization of maleic acid or the like, or an amorphous polyester resin or polyamide resin can be used.
In addition, the thermoplastic resin other than the PET resin or the polyester resin used in the present invention has various additives such as an injection-molded product or a stretch-molded container formed by stretching this, for example, A coloring agent, an ultraviolet absorber, a release agent, a lubricant, a nucleating agent, an inorganic layered compound for increasing gas barrier properties, and the like can be blended.

(Stretch molded container)
The stretch-molded container of the present invention can be manufactured by stretch-molding the above-described injection-molded product, and in particular, can be manufactured by biaxial stretch-blow molding of a preform molded by injection molding.
In the present invention, stretch blow molding is preferably performed under a stretching temperature condition of 110 to 120 ° C. That is, under high-temperature stretching conditions that can impart excellent heat resistance of the stretched molded product, the stretching balance will be deteriorated unless high-speed stretching is performed, but there is a limit to increasing the stretching speed, which is conventionally low. Stretch molding was performed at a low temperature (95 to 105 ° C.) at the expense of the merit of high-temperature stretching called residual strain, but by using the preform that is an injection molded product of the present invention, a high temperature condition of 110 to 120 ° C. Even in the case of stretching under, it is possible to obtain a stretch-formed container having an excellent stretch balance by using a conventional stretch molding apparatus without increasing the stretching speed as much as possible. The stretching temperature, that is, the heating temperature of the preform, is the outer surface temperature of the preform immediately before the stretch blow molding, and can be measured by a radiation thermometer, a thermal image measuring instrument, or the like.
In order to heat the preform uniformly and at high speed to the above temperature, it is necessary to heat the preform from inside and outside of the preform by means such as hot air, infrared heater, high frequency induction heated iron core internal insertion, etc. preferable.

This preform is supplied into a stretch blow molding machine known per se, set in a mold adjusted to a temperature of 60 to 120 ° C., stretched in the axial direction by pushing a stretching rod, and blown in blow air. To stretch in the circumferential direction. In order to efficiently perform stretch molding at a high temperature in the method of the present invention, it is preferable to blow hot air at 100 to 150 ° C. as blow air.
In addition, the effect of coexistence of the low residual strain and stretching balance obtained in the present invention can be obtained regardless of heat setting, and in the stretch-molded container of the present invention, without performing heat fixing, Heat resistance to temperatures in the range of 60 to 100 ° C. such as heat resistant (hot filling) applications and heat and pressure application containers can be expressed. This effectively eliminates the problems caused by heat fixing, such as the need for frequent cleaning of the mold, or a decrease in transparency when the number of moldings increases, and also requires heat fixing. Energy can be reduced, but when heat resistance to high temperatures over 100 ° C that can handle boil sterilization or retort sterilization is required, or when the container is light and the container thickness is reduced, It is not excluded to perform heat fixing until such a case is achieved.

In the present invention, since stretch blow molding is performed at a temperature higher than usual, there is a risk of oligomer precipitation due to high temperature stretching. Therefore, in order to prevent this, it is preferable to use a surface-treated mold. Further, in order to increase the releasability and suppress deformation after molding, it is preferable that the molded product is reliably cooled by circulating room temperature or cooling air in the blow bottle as cooling air at the time of mold release.
The draw ratio in the biaxially stretched container is suitably 1.5 to 25 times in terms of area ratio. Among these, the axial draw ratio is 1.2 to 6 times, and the circumferential draw ratio is 1.2 to 4.5. It is preferable to double.

As mentioned above, when obtaining high heat resistance that can handle processing exceeding 100 ° C., such as boil sterilization and retort sterilization, or when heat resistance is achieved and the container thickness is reduced to reduce the weight of the container For example, it is preferable to heat-set at 150 to 230 ° C., preferably 150 to 180 ° C. after the stretch molding. The heat setting can be performed by means known per se, and can also be performed by a one-mold method performed in a blow mold, or a two-mold performed in a heat mold separate from the blow mold. It can also be done by law.
From the viewpoint of handling properties, it is desirable to cool with cold air when taking out from the mold after heat setting.
Further, in the present invention, it is possible to improve the heat resistance of the part that has been stretched in the stretch blow container, but in the part that is not stretched on the molding method such as the container mouth, the wall thickness can be set thicker, Heat resistance can be improved by, for example, heat crystallization before blow molding.

(material)
The material used in the Example is shown.
(1) Polyethylene terephthalate resin PET1: BK6180 (manufactured by Nippon Unipet Co., Ltd.), isophthalic acid copolymerization ratio = 1.5 mol
% Copolymerized PET (IV = 0.83)
PET2: RT543CTHP (manufactured by Nippon Unipet Co., Ltd.), HomoPET (IV = 0.75)

(2) Chain extender ADR-4368C (manufactured by BASF), epoxy group-containing styrene-acrylic copolymer. Epoxy equivalent = 286 g / mol, weight average molecular weight (Mw) = 6700, weight average number of epoxy functional groups (number of epoxy groups in one molecule) = 9 to 10 (3) terminal functional group sealant LA-1 (Nisshinbo Chemical ( ), A carbodiimide compound.

(Preparation of masterbatch resin pellets)
Concentration of polyethylene terephthalate resin (PET1), chain extender and terminal functional group sealant using a twin-screw kneading extruder with granulation equipment (TEM-26SS: Toshiba Machine Co., Ltd.) with a barrel set temperature of 280 ° C Amorphous masterbatch resin pellets configured to have a predetermined concentration were produced. As shown schematically in FIGS. 3 and 4, the twin-screw extruder has a barrel divided into 10 sections, a portion indicated by N in the figure is a kneading portion, and the other hatched portion is a conveyance portion. . In the figure, the part indicated by F1 is a PET resin supply part, and the part indicated by F2 is a chain extender supply part.
When producing an amorphous masterbatch resin pellet, the polyethylene terephthalate resin and the terminal functional group sealing agent are charged together from the material inlet of the first section of the barrel on the most upstream side. This was carried out in two ways: simultaneous charging with the resin and the terminal functional group blocking agent, or sequential charging with heating and melting at 120 ° C. and charging from the barrel opening of the sixth compartment from the upstream.
In addition, the screw configuration is such that when the length from the 6th section to the 10th section where the chain extender is charged is L, the kneading zone from the position of 0.56L downstream from the 6th section of the barrel, Configuration 1 (FIG. 3) set in the range of 0.11L and Configuration 2 (FIG. 4) set in the range of 0.21L from the position of 0.40L downstream from the sixth section of the barrel to the downstream side. Went on the street.
The amorphous masterbatch resin pellets thus obtained were heated under vacuum at 150 ° C. for 4 hours for crystallization and drying treatment.

(Production of 3mm thick injection molded plate)
The polyethylene terephthalate resin that has been dried and the masterbatch pellets are injected into an injection molding machine (NN75JS :(
Supplied to the hopper of Niigata Works), barrel set temperature is 280 ° C, cycle time 36
Injection molding was performed in seconds to form an injection molded plate of 90 × 90 × 3 mm.

(Biaxial stretching test)
The injection molded plate was biaxially stretched with a biaxial stretching test apparatus (x6H-S: Toyo Seiki Seisakusho Co., Ltd.). The molding conditions are as follows.
Chamber temperature: 115 ° C
Heating time before stretching: 5 minutes 30 seconds Stretching method: simultaneous biaxial stretching Stretching ratio: 3 times on the vertical axis and 3 times on the horizontal axis Stretching speed: 10 m / min in both directions

(Creation of stretch blow bottle)
The above masterbatch resin pellets and dry blended polyethylene terephthalate and dry blended at a specified mixing ratio are supplied to the hopper of an injection molding machine (NN75JS: Niigata Iron Works), and the barrel set temperature is 280 ° C. The bottle preform having a weight of 28 g and a diameter of 28 mm was molded by injection molding at a cycle time of 30 seconds.
After that, the body of the preform, whose mouth has been whitened by heating in advance, is heated from the outside with an infrared heater so that the surface temperature becomes 115 ° C. with a heated iron core, and then biaxially stretched. Then, a stretch blow bottle shown in FIG. 3 having a capacity of 500 ml with an approximate stretch ratio of 3 times in length, 3 times in width, and 9 times in area was formed. The mold temperature was set at 155 ° C. Moreover, room temperature (20 degreeC) and 140 degreeC compressed air was used for blow air, and room temperature (20 degreeC) cooling air was introduce | transduced in the container at the time of mold release.

(Various measurements)
(1) ΔTc1 by differential scanning calorimeter
About 5 mg sample piece was cut out from the central part of the injection molded plate or near the bottom center of the stretch blow bottle, and the crystallization temperature was measured with a differential scanning calorimeter (Diamond DSC: manufactured by Perkin Elmer). Here, the crystallization temperature refers to the temperature at which the heat generation due to crystallization reaches a peak. A series of measurements was performed under the following measurement conditions (i) to (iv).
(I) Temperature rise from 20 ° C. to 290 ° C. at 10 ° C./min (ii) Hold at 290 ° C. for 5 minutes (iii) Temperature drop from 290 ° C. to 20 ° C. at 150 ° C./min (iv) Temperature from 20 ° C. to 290 ° C. Temperature rise at 10 ° C / min. Among these, the crystallization exothermic peak temperature measured in (i) is 1stTc1, (iv)
Is defined as 2ndTc1, and ΔTc1 = 2ndTc1-1-1stTc1
And

(2) Molecular weight component content of molecular weight of 3.0 × 10 ⁵ or more by gel permeation chromatography (GPC) 1,1,1,3,3,3-hexafluoro-2-isopropanol and chloroform weight ratio A 10 mg sample resin piece is completely dissolved in 5 ml of a 10:90 mixed solvent, passed through a filter with a pore size of 0.45 μm, and then gel permeation chromatography equipped with light scattering, a differential refractometer, and a differential pressure viscosity detector. Analysis was performed using a graph (Integrated System For GPC / SEC: manufactured by Asahi Techneion Co., Ltd., Triple Detector Module TriSEC Model 302: manufactured by Viscotek). OmniSEC4.2 (manufactured by Viscotek) is used for analysis and analysis software, and the horizontal axis represents the cumulative weight fraction and the vertical axis represents the weight average molecular weight, and the content of molecular weight components of 3.0 × 10 ⁵ or more is calculated. did. The measurement conditions are as follows.
Developing solvent: Chloroform Flow rate: 1 ml / min.
Guard column: TSK guard column HXL-L (manufactured by Tosoh Corporation)
Column used: TSKgel G4000HXL and TSKgel G5000HXL (both manufactured by Tosoh Corporation)
In addition, PolyCALTM standards, TDS-PS-NB, Polystyrene standards-ps235k and ps99k (all manufactured by Viscotek) were used as standard samples for calibration.

(3) Judgment of stretch balance (3-1) Stretch balance of bottle A biaxial stretch blow was performed in advance by placing dots at 10 mm intervals from the neck ring toward the bottom of the preform body with an oil pen. In this blow bottle, those with a hitting point interval of about 30 mm in the barrel portion and uniform were determined to have good stretching balance (◯).
(3-2) Stretching balance of stretch-molded sheet An injection-molded plate in which a 10 mm square grid is previously written with oil-based ink is biaxially stretch-molded according to the above method, and the grid is uniformly stretched in the stretch-molded sheet obtained. What was done was set as (circle), and what was not extended | stretched in the center vicinity was extended as x. In addition, the thing which crystallized excessively during the heating and the stretch molding was impossible was not determined.
FIG. 1 and FIG. 2 are a schematic diagram of the outer appearance of a sheet with a good stretching balance and a schematic diagram of the outer appearance of a sheet with a poor stretching balance, respectively.

(4) Haze
The haze of the sample obtained by cutting out the injection molded plate and the body panel portion of the molded stretch blow bottle was measured using a color computer (SM-4: Suga Test Instruments Co., Ltd.). The measured value was an average value of three arbitrary points.

(Example 1)
When producing the master batch pellet, the screw configuration of the twin screw extruder to be used was configured as shown in FIG. 3, and the chain extender was sequentially added from the middle of the barrel to perform extrusion molding. The master batch pellet and dry-treated polyethylene terephthalate resin (PET1) were dry blended so that the chain extender concentration was 1000 ppm and the end functional group sealant concentration was 4000 ppm, and an injection molding machine (NN75JS: Niigata Co., Ltd.). And then injection-molded at a barrel set temperature of 280 ° C. and a cycle time of 36 seconds to form an injection-molded plate of 90 × 90 × 3 mm. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.

(Example 2)
An injection-molded plate was molded in the same manner as in Example 1 except that the terminal group sealant concentration was 100 ppm. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.

(Example 3)
An injection-molded plate was molded in the same manner as in Example 1 except that the chain extender concentration was 20 ppm and the end group sealant concentration was 100 ppm. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.

Example 4
An injection-molded plate was molded in the same manner as in Example 1 except that the terminal group sealant concentration was 1000 ppm. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.

(Comparative Example 1)
An injection-molded plate was molded in the same manner as in Example 1 except that the chain extender concentration was 5000 ppm and the end group sealant concentration was 20000 ppm. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.

(Comparative Example 2)
An injection-molded plate was molded in the same manner as in Example 1 except that the chain extender concentration was 9 ppm and the end group sealant concentration was 4000 ppm. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.

(Comparative Example 3)
An injection-molded plate was molded in the same manner as in Example 1 except that the chain extender concentration was 1000 ppm and the end group sealant concentration was 90 ppm. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.

(Comparative Example 4)
An injection-molded plate was molded in the same manner as in Example 4 except that when the master batch pellet was prepared, the chain extender was simultaneously charged into the material inlet together with the polyethylene terephthalate resin and the terminal functional group sealant. ΔTc1, Mw 3.0 × 10 ⁵ or more molecular weight component content and Haze of this molded plate were measured according to the above methods. Further, this molded plate was biaxially stretched in accordance with the above-described method, and the stretch balance was evaluated.
The results of each measurement are shown in Table 1.

(Example 5)
When producing the master batch pellet, the screw configuration of the twin screw extruder to be used was configured as shown in FIG. 4, and the chain extender was added from the middle of the barrel to perform extrusion molding. The master batch pellet and dry-treated polyethylene terephthalate resin (PET2) are dry blended so that the chain extender concentration is 1000 ppm, and supplied to the hopper of an injection molding machine (NN75JS: Niigata Engineering Co., Ltd.) Injection molding was performed at a barrel set temperature of 280 ° C. and a cycle time of 36 seconds to form a bottle preform, and then a stretch blow bottle was molded. At this time, the heating temperature of the preform, that is, the stretching temperature was set to 115 ° C., the heat setting temperature of the blow mold was set to 155 ° C., and the blow air temperature was set to room temperature (20 ° C.). The stretch blow bottle was measured for ΔTc1, a molecular weight component content of Mw 3.0 × 10 ⁵ or more, and Haze according to the method described above. Moreover, the stretch balance was evaluated.

(Comparative Example 5)
When producing the master batch pellets, stretch blow bottles were produced in the same manner as in Example 5 except that the screw configuration of the twin screw extruder used was changed to the configuration 1 shown in FIG. The stretch blow bottle was measured for ΔTc1, a molecular weight component content of Mw 3.0 × 10 ⁵ or more, and Haze according to the method described above. Moreover, the stretch balance was evaluated.
The results of each measurement are shown in Table 2.

Since the injection molded product of the present invention is excellent in transparency and the crystallization speed is controlled, a stretch molded product excellent in stretch balance can be obtained by being subjected to stretch molding, and the thickness distribution is Because it is stable, it has excellent mechanical strength such as buckling strength, and appearance abnormalities such as swell and sink are sufficiently suppressed, so it is applied to beverages that require hot filling and hot vendors. It can be suitably used for heat-resistant containers such as beverages.
In addition, in the method for producing an injection-molded article of the present invention, it is possible to produce a branched polymer having an appropriate molecular weight by blending a small amount of a chain extender and a terminal functional group blocking agent with a general-purpose PET resin. An injection-molded product with a controlled crystallization rate can be provided, and it is excellent in productivity and economy, and can be suitably used for general-purpose containers that are mass-produced.

Claims (3)

Consists of an ethylene terephthalate polyester resin (A) and a chain extender (B) having a functional group reactive with the terminal functional group of the polyester resin (A), and a weight average molecular weight Mw of 3.0 × 10 ⁵ or more An injection-molded article comprising a resin composition containing a high molecular weight component in an amount of 1.0% by weight or more,
A terminal functional group sealant (C) composed of a carbodiimide compound with respect to the terminal functional group of the polyester resin (A) is blended in the ethylene terephthalate-based polyester resin (A) at a concentration of 100 to 15000 ppm, and the chain extension Agent (B) is an epoxy-modified styrene / (meth) acrylic copolymer having a weight average epoxy functional group number of 4 or more, and is contained at a concentration of 10 to 4000 ppm,
The following formula ΔTc1 = 2ndTc1-1−1stTc1
In the formula, 2ndTc1 is a crystallization exothermic peak measured with a differential scanning calorimeter for a sample which has been rapidly melted after heating and melting for 5 minutes, and 1stTc1 represents a crystallization exothermic peak measured with a differential scanning calorimeter for the sample before melting. ,
A value of ΔTc1 represented by the formula is an injection-molded article characterized by being 20 ° C. or less. A stretch molded container having a layer comprising an ethylene terephthalate type polyester resin, the stretch molded container of claim 1 Symbol placement of the injection molded article obtained by biaxial stretch blow molding. An ethylene terephthalate-based polyester resin (A) is blended with a terminal functional group sealing agent (C) for the terminal functional group of the polyester resin (A), and then functionally reactive with the terminal functional group of the polyester resin (A). A resin composition containing a high molecular weight component having a weight average molecular weight Mw of 3.0 × 10 ⁵ or more in an amount of 1.0% by weight or more by blending a chain extender (B) having a group and melt-kneading. A method for producing an injection-molded article by preparing a product and injection-molding the resin composition ,
A terminal functional group sealant (C) composed of a carbodiimide compound with respect to the terminal functional group of the polyester resin (A) is blended in the ethylene terephthalate-based polyester resin (A) at a concentration of 100 to 15000 ppm, and the chain extension A method for producing an injection-molded article, wherein the agent (B) is an epoxy-modified styrene / (meth) acrylic copolymer having a weight average number of epoxy functional groups of 4 or more and is contained at a concentration of 10 to 4000 ppm .

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