JPH06116380A - Molded article of container - Google Patents

Abstract

PURPOSE:To obtain a molded article of container having improved processability, productivity, excellent heat resistance, food resistance, chemical resistance, gas barrier properties, etc., comprising a readily crystallizable polyethylene terephthalate-based copolymer prepared by copolymerizing a specific compound. CONSTITUTION:The molded article comprises a polyethylene terephthalate-based copolymer having 1-50wt.% unit of the formula (R<1> is 2-18C bifunctional group; (k) is 5-40). The copolymer is preferably obtained from polyethylene terephthalate or its raw material and a compound providing the unit of the formula by esterification. An adduct of bisphenol A with polyethylene oxide or an adduct of bisphenol A with polybutylene oxide may be preferable as the compound providing the unit of the formula. The molded article is preferably produced by optionally blending the copolymer with a filler, etc., to give a composition, making the composition into a sheet and subjecting the sheet to vacuum (compressed air) molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded container of a crystallizable polyethylene terephthalate copolymer having excellent processability, productivity, heat resistance, food resistance, chemical resistance and gas barrier property.

[0002]

2. Description of the Related Art Polyethylene terephthalate (PET) resin has characteristics such as heat resistance at a relatively high temperature due to crystallization, good resistance to edible oils, gas barrier properties, and the like. Since it has good thermoformability during crystallization, it is widely used as a container material including food containers.

As described above, the PET resin develops its excellent properties by crystallization, and therefore, it is general that the PET resin is shaped and crystallized at the time of molding.

PET resin has a drawback that it is difficult to crystallize as compared with polybutylene terephthalate resin which is the same polyester resin, and several methods have been proposed in order to obtain a molded product having a practical crystallinity. ing. For example, in the method described in Japanese Patent Publication No. 1-9179,
A product with sufficient crystallinity is obtained by blending with polyolefin. Further, in the method described in JP-A-1-66265, a crystallization rate is improved by using a liquid crystal polymer and a polyolefin as a nucleating agent.

In addition, a method of improving the crystallization characteristics of PET resin for containers by using an inorganic nucleating agent such as talc is well known.

PET having improved crystallization characteristics in this way
Resin is used by being molded into a container. In this case,
Productivity during molding is achieved by the short time required for shaping and crystallization, which is generally dependent on the mold temperature. For example, in the case of a PET resin composition having a slow crystallization rate, the mold temperature is raised to promote crystallization. In this case, in order to obtain a dimensionally stable molded product, it takes a relatively long time in the mold. The molded product is held in, or a cooling mold is separately prepared, and the mold is used for shaping. Therefore, a method that does not require shaping and crystallization at a relatively low mold temperature or a cooling mold is important and desired for improving productivity.

As described above, many methods for improving the crystallization characteristics of PET resin have been proposed, but they are still insufficient and further improvement is required to improve productivity.

The present invention makes it possible to obtain T by copolymerization with a specific compound.
It is possible to shape and crystallize with a low temperature mold by using a crystallizable PET-based copolymer having a reduced g, and to improve the dimensional stability of a molded product without using a cooling mold. The purpose of the invention is to improve the productivity and at the same time improve the impact strength of the molded container.

[0009]

According to the present invention, an easily crystallizable PET copolymer obtained by copolymerizing a specific compound is used as a molding material for a container, and dimensional stability, productivity, heat resistance, workability, gas barrier property are obtained. The present invention provides a molded container product having excellent chemical resistance, impact resistance, and the like. The general formula (I):

[0010]

[Chemical 3]

(Wherein R ¹ is a divalent group having 2 to 18 carbon atoms, k is an integer of 5 to 40, and k R ¹ need not be the same). % (% By weight, the same applies below) to a molded container product made of a polyethylene terephthalate copolymer.

[0012]

EXAMPLES Polyethylene terephthalate (PET) copolymers used in the present invention are produced from polyethylene terephthalate (PET) or its raw material and a compound which gives a unit represented by the general formula (I) by esterification. Is.

Since the PET-based copolymer contains PET or this raw material as a constituent element, it has properties such as good mechanical strength and chemical resistance which are characteristic of using a PET resin. Since the unit represented by the formula (I) is contained as a constituent element, the crystallization promoting effect, which is a characteristic of using the polyoxyalkylene glycol unit, is large, and the mold temperature at the time of molding the container can be lowered, It has the property of speeding up the cycle and increasing productivity.

The proportion of the unit represented by the general formula (I) in the PET copolymer is 1 to 50%, preferably 3 to 35%, particularly preferably 25 to 35%.

PE of the unit represented by the general formula (I)
Since the proportion of the T-based copolymer is 1 to 50%, the characteristics achieved by using the unit represented by the general formula (I) and the characteristics achieved by using PET or this raw material are A well-balanced expression, a large effect of promoting crystallization, and a molded product with little deterioration in mechanical strength and chemical resistance can be obtained.

Intrinsic viscosity (IV) of the PET-based copolymer
Is 2 in a mixed solvent consisting of phenol / 1,1,2,2-tetrachloroethane = 1/1 (weight ratio, the same applies hereinafter).
When measured at 5 ° C., it is preferably 0.4 to 1.2, particularly preferably 0.6 to 1.0. When the intrinsic viscosity is less than 0.4, the mechanical strength becomes unsuitable for use as a decoy container. On the other hand, when it exceeds 1.2, the crystallization characteristics are lowered and the productivity during processing is lowered.

The PET copolymer has a Tg of 20 to 20.
The temperature is preferably 80 ° C., more preferably 50 to 70 ° C., from the viewpoint of enhancing the crystallization promoting effect and improving the productivity.

The PET is a linear saturated resin obtained by using terephthalic acid or a derivative thereof having an ester forming ability as an acid component and ethylene glycol or a derivative thereof having an ester forming ability as a glycol component. Is.

The polyethylene terephthalate contains 50
%, Other components such as other aromatic dicarboxylic acid having 8 to 14 carbon atoms, aliphatic dicarboxylic acid having 4 to 8 carbon atoms, alicyclic dicarboxylic acid having 8 to 12 carbon atoms, and 3 carbon atoms
Units derived from an aliphatic diol having 10 to 10, an alicyclic diol having 6 to 15 carbon atoms, an aromatic diol having 6 to 15 carbon atoms, and the like may be contained. Specific examples thereof include isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, adipic acid,
Sebacic acid, cyclohexanedicarboxylic acid, propane-
1,3-diol, butane-1,4-diol, pentane-1,5-diol, cyclohexane-1,4-dimethanol, 2,2-dimethylpropane-1,3-diol, 2,2-bis ( 4'-hydroxycyclohexyl)
Propane, 2,2-bis (4'-hydroxyphenyl)
Examples include units derived from propane and the like.

The above general formula (I):

[0021]

[Chemical 4]

R ^{1 in the} unit represented by has 2 carbon atoms
A divalent group of -18, k is an integer of 5-40, and k R < ¹ >'s need not be the same.

Specific examples of the compound giving the unit represented by the general formula (I) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like, and the general formula (II):

[0024]

[Chemical 5]

(In the formula, R ² is a divalent hydrocarbon group having 2 to 4 carbon atoms, and X is, for example, —C (CH ₃ ) ₂ —, —CH.
_{2 -, - S -, -} SO 2 -, - CO- 2 divalent linking group, m and n are each an integer of 5-15, such as, (m + n)
R ^{2 s} need not be the same) and a polyether compound providing a unit represented by Further, it may be a copolymer of the unit components constituting these compounds. These may be used alone or in combination of two or more.

Specific examples of the compound providing the unit represented by the general formula (II) include a polyethylene oxide adduct of bisphenol A and a polybutylene oxide adduct of bisphenol A.

When the unit represented by the general formula (I) is the unit represented by the general formula (II), it is particularly preferable in terms of excellent heat resistance and deterioration during processing, for example, reduction of viscosity. .

P used for producing the molded article of the present invention
In the ET copolymer, if necessary, an organic or inorganic reinforcing material and a filler are added to 2 parts per 100 parts of the PET copolymer.
It can be blended in the range of 00 parts, preferably 150 parts or less. If the blending amount exceeds 200 parts, the molding process becomes difficult and the mechanical strength of the composition decreases.

The organic or inorganic reinforcing materials and fillers are those added for the purpose of enhancing the function of the PET copolymer used in the present invention, and specifically, glass fiber, carbon fiber, asbestos, aroma. Fiber reinforcements such as group polyamide fibers, silicon carbide fibers, potassium titanate fibers, mineral fibers, calcium carbonate, magnesium carbonate, calcined clay,
Examples thereof include graphite, mica, talc, glass beads, metal powder and fluororesin powder.

The PET copolymer used in the present invention contains, in addition to the above-mentioned components, additives generally used for PET resins, such as antioxidants, colorants, crystallization accelerators, plasticizers and resins other than polyester. It can also be blended.

The shape of the molded container of the present invention varies depending on its use, but is generally bottle-shaped, box-shaped, tray-shaped or the like suitable for containing or placing foods, industrial products, industrial raw materials and the like. Is.

The degree of crystallinity of the container molded product is 20% or more when molded at a mold temperature of 120 ° C. from the viewpoint of container heat resistance and chemical resistance, and 28% or less from the viewpoint of toughness. It is preferable. Further, the crystallinity can be easily controlled with this composition, and the toughness can be easily ensured within a wide temperature range. Also,
Although the crystallinity does not increase even after heating and using the container, the toughness is maintained, and when the conventional molded product is heated and used in an oven at about 220 ° C, crystallization progresses and becomes very brittle. Since the molded product of the present invention has toughness even after heating and has a higher strength than the conventional molded product, it is very effective in handling and use. Moreover, the wall thickness is 0.3 to 2.0 m.
When it is molded, it is preferable that the sheet is uniformly stretched when molded, from the viewpoint of container structural strength and impact strength, and if it is too thick, it is economically disadvantageous.

The method for producing the above-mentioned container molded article is not particularly limited, but a preferred method is to process the above composition into a sheet, and then perform vacuum forming or vacuum pressure forming. At this time, the sheet used for molding has a crystallinity of 1
It is preferably 5% or less, and more preferably 5 to 13% from the viewpoint of storage stability of the sheet, oven control during molding, and the like.

When the PET-based copolymer forming sheet used in the present invention satisfies the above-mentioned requirements and is formed by vacuum forming or vacuum pressure forming, one-step forming is performed without using a cooling die. Even so, since the mold is at a low temperature, a container molded product without deformation can be obtained.

In addition, the container molded article may be blow molded,
It may be manufactured by injection molding or the like.

When processing the molded article of the container of the present invention, the water content in the composition is 0.02% or less, particularly 0.0
It is preferably 1% or less. With such a water content, deterioration due to hydrolysis can be prevented and reduction in strength can be prevented.

The mold used in the method for producing the above-mentioned container molded product varies depending on the container to be manufactured, but is not particularly limited as long as it is one normally used as a mold.

Further, the conditions in the above-mentioned manufacturing method are preferably a mold temperature of 110 to 130 ° C. from the viewpoint of performing one-stage molding, and a mold temperature of 130 ° C. or less prevents deformation at the time of mold release, and It is preferable from the economical point of view.

Next, the container molded article of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The crystallinity is measured by DSC at 10 ° C. /
Temperature rise in minutes (20-290 ° C), hold at 290 ° C for 3 minutes,
Then, the temperature is lowered at 10 ° C./min (290 to 20 ° C.) and ΔHm
(Crystal melting endotherm) and ΔHch (calorific value of crystallization peak at elevated temperature) were calculated and calculated from the following crystallinity calculation formula.

Crystallinity = (ΔHm-ΔHch) × 100
/140.06 Examples 1 to 3 The compositions shown in Table 1 were extruders (single screw, screw diameter 40 m).
m) to obtain a sheet having a thickness of 0.7 mm and a width of 500 mm. At this time, the cast roll was cooled with cold water at 15 ° C. The crystallinity of the obtained sheet is 8.3.
%, 10.2%, 12.5% (Examples 1 to 3).

Then, vacuum pressure forming was carried out using this sheet and a cup-shaped mold having a diameter of 105 mm, a bottom diameter of 75 mm and a height of 40 mm. Molding conditions were a mold temperature of 120 ° C., an oven temperature of 300 ° C., and a heating time of 4.0 seconds. With a molding time of 6 seconds, a container molded product having good dimensional stability was obtained.
A part of this container was cut out and a DSC measurement was performed to measure the crystallinity. Further, the obtained container molded product was put in an oven at 220 ° C. for 30 minutes and a heat resistance test was conducted, but no shape change was observed.

The results are shown in Table 1.

The PET copolymer (1) shown in Table 1 is used.
Is a copolymer of 10% of a polyether having an average molecular weight of 800 in which ethylene oxide is added to bisphenol A I
V 0.82 (phenol / 1,1,2,2-tetrachloroethane = 1/1 mixed solvent, measured at 25 ° C., hereinafter the same), PET-based copolymer, PET-based copolymer (2)
A PET copolymer (IV 0.75) obtained by copolymerizing 6% of polyethylene glycol having an average molecular weight of 600, and a PET copolymer (3) are polyethylene glycol-polypropylene glycol block copolymers (ethylene oxide /
Propylene oxide = 2/8 (weight ratio), average molecular weight 8
00) in 20% of IV 0.73 PET copolymer, PET (1) is IV 0.80 PET, stabilizer (1) is distearyl pentaerythritol diphosphite, polypropylene (1) is Sumitomo Chemical Co., Ltd.
Sumitomo Noprene Y501N and Talc (1) manufactured by Nippon Talc Co., Ltd. are Microace K-1.

Comparative Examples 1 and 2 Sheets were prepared using the compositions shown in Table 1 in the same manner as in Examples 1 to 3 (sheet crystallinity of 8.5% and 10.2).
%), Vacuum pressure molding was carried out, but the shape of the container molded at a mold temperature of 120 ° C. was not round, sharp, and cup-shaped. This molded product is
It was severely deformed in a heat resistance test in an oven at 220 ° C.
When the mold temperature was 140 ° C. or higher, the mold did not deform in the heat resistance test. At this time, the shortest molding time that a good product was obtained was 9 seconds.

The results are shown in Table 1.

[0047]

[Table 1]

[0048]

EFFECTS OF THE INVENTION When the container molding of the present invention is molded using the composition used in the present invention, it has excellent processability and productivity, and is excellent in heat resistance, food resistance, chemical resistance, gas barrier property and the like. A molded container can be obtained.

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Claims (7)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R ¹ is a divalent group having 2 to 18 carbon atoms, and k is 5 to 4
A container molded product made of a polyethylene terephthalate-based copolymer containing 1 to 50% by weight of a unit represented by an integer of 0 and k R ¹ need not be the same. 2. The molded container product according to claim 1, wherein the polyethylene terephthalate copolymer has a Tg of 20 to 80 ° C. 3. The unit represented by the general formula (I) is represented by the general formula (II): (In the formula, R ² is a divalent hydrocarbon group having 2 to 4 carbon atoms, X is a divalent bonding group, m and n are each an integer of 5 to 15, and
The container molded article according to claim 1, which is a unit represented by (m + n) R ^{2 s} need not be the same. 4. The bonding group represented by X in the general formula (II) is —C (CH ₃ ) ₂ —, —CH ₂ —, —S—,
-SO ₂ - or -CO- and a third aspect of the container molded article. 5. The container molded product according to claim 1, wherein the container molded product is molded by vacuum or vacuum pressure forming from a sheet. 6. The container molded product according to claim 5, wherein the vacuum or vacuum pressure molding is molding without using a cooling mold. 7. The crystallinity of the sheet when forming a container molded article from the sheet by a thermoforming method is 15% or less,
The container molded article according to claim 5, wherein the crystallinity of the container molded at a mold temperature of 120 ° C is 20% or more.