JPH06107928A - Polyester resin composition and container comprising the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a polyester resin composition having a high ultraviolet absorption performance and capable of blocking the transmission of ultraviolet rays to protect the contents when formed into a container. [Structure] Thermoplastic polyester resin and general formula (I) (Wherein R ¹ represents a lower alkyl group, R ² represents a lower alkylene group, R ³ represents an organic group, and n represents an integer of 0 to 3). A polyester resin composition comprising The weight ratio of these thermoplastic polyester resin / acrylic resin is 100.
/0.01 to 100/10.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel polyester resin composition and a container comprising the polyester resin composition. The polyester resin composition of the present invention has a high ultraviolet absorption performance. INDUSTRIAL APPLICABILITY The container of the present invention can effectively exhibit the high ultraviolet absorption performance of the polyester resin composition and protect the contents from the harmful effects of ultraviolet rays.

[0002]

2. Description of the Related Art Thermoplastic polyester resins are
For example, it is known that when exposed to sunlight for a long period of time, photo-deterioration occurs, and undesired phenomena such as a decrease in the degree of polymerization of the polymer, deterioration of physical properties due to gelation, and coloring occur. On the other hand, in recent years, a wide variety of products such as soft drinks, alcoholic drinks, edible oils, foods, cosmetics, pharmaceuticals and shampoos have been housed in thermoplastic polyester resin containers such as polyethylene terephthalate for sale and storage. Such a thermoplastic polyester resin container is required to be transparent so that the contents can be seen. However, the transparent thermoplastic polyester resin container is about 250
Since a considerable proportion of ultraviolet rays having a wavelength of 400 nm is transmitted, the contents may be adversely affected by ultraviolet rays such as alteration, discoloration, and decomposition.

Therefore, various attempts have been made to blend an ultraviolet absorber into the thermoplastic polyester resin for the purpose of protecting the thermoplastic polyester resin itself from ultraviolet rays or the contents in a transparent thermoplastic polyester resin container. There are some UV absorbers that have been commercialized. UV absorbers for thermoplastic polyester resins include
In addition to requiring high ultraviolet absorption performance, it is also necessary that the compatibility with the thermoplastic polyester resin is high in order to suppress turbidity of the color tone of the molded product and deterioration of the physical properties. In addition, the ultraviolet absorber for thermoplastic polyester resin has the ability to prevent contamination of contents when molded into a container,
For the purpose of long-term maintenance of ultraviolet absorption performance, it is necessary to be difficult to extract. Further, a UV absorber for a thermoplastic polyester resin needs to have high thermal stability. That is, since the thermoplastic polyester resin has a high polycondensation temperature and a high melting point, if the UV absorber used has insufficient thermal stability, it is added under melting conditions during or after the production of the polyester. When this is done and when the polyester is melt-molded after its addition, deterioration such as thermal decomposition occurs. As a result, the ultraviolet absorption performance of the obtained resin composition and the ultraviolet screening performance of the container molded from the resin composition become insufficient, and the color tone of these becomes poor.

In order to satisfy the requirements of high compatibility and low extractability with respect to the above thermoplastic polyester resin, an ultraviolet absorber having a reactive functional group introduced so that it can be incorporated into a polyester molecule is available. Proposed, cyanoacrylate type (Tokusho Sho 62
-501856 gazette and special table Sho 62-501857
JP-A No. 63-172729) and benzotriazole compounds (see JP-A-63-172729).

[0005]

However, most of the conventional ultraviolet absorbers have the above-mentioned high ultraviolet absorption performance, high compatibility with thermoplastic polyester resins, low extractability and high thermal stability. At least one of them has a drawback, and is not always satisfactory. For example,
JP-A-62-501856 and JP-A-62-51856
The cyanoacrylate-based UV absorber proposed in JP-A-501857 still has insufficient UV absorption performance and thermal stability. Further, the above-mentioned JP-A-63-172729
The benzotriazole-based UV absorbers described in Japanese Patent Laid-Open Publication No. 1994-242242 are still insufficient in thermal stability. Therefore, one of the objects of the present invention is to have a high ultraviolet absorbing ability, and to maintain the high ultraviolet absorbing ability even after being exposed to high temperature conditions such as melt molding, and the ultraviolet absorbing component. To provide a polyester resin composition in which the original transparency of the polyester resin can be maintained and the ultraviolet absorbing component is not extracted. Another object of the present invention is to provide a polyester container which is excellent in the ability to shield the contents from ultraviolet rays even if it is transparent, and in which the ultraviolet absorbing component does not contaminate the contents.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a thermoplastic polyester resin composition containing a specific amount of a specific ultraviolet absorbing polymer compound and a thermoplastic polyester resin composition comprising the same The inventors have found that the container can achieve the above object, and have completed the present invention.

One of the objects of the present invention is to use 100 parts by weight of a thermoplastic polyester resin and the following general formula (I).

[0008]

[Chemical 2]

(In the formula, R ¹ represents a lower alkyl group, and R ²
Represents a lower alkylene group, R ³ represents an organic group, and n represents an integer of 0 to 3)

This is achieved by providing a polyester resin composition characterized by comprising 0.01 to 10 parts by weight of an acrylic resin containing a structural unit represented by:

Another object of the present invention described above is achieved by providing a container made of the polyester resin composition.

The thermoplastic polyester resin in the present invention is not particularly limited, and various known ones can be used, but an aromatic ring-containing aromatic ring in the main repeating unit in the main chain of the molecule. Polyester is preferred. This aromatic polyester is usually obtained by polycondensing a difunctional aromatic carboxylic acid or its ester-forming derivative and a diol compound as main monomers.

Examples of the bifunctional aromatic carboxylic acid referred to herein include terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, and 2,6- Naphthalene dicarboxylic acid, 4,4 '
-Biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylisopropylidenedicarboxylic acid, 1,2-diphenoxyethane -4,4'-
Aromatic dicarboxylic acids such as dicarboxylic acid, 2,5-anthracene dicarboxylic acid, 2,6-anthracene dicarboxylic acid and 2,5-pyridinedicarboxylic acid; aromatic hydroxy such as β-hydroxyethoxybenzoic acid and p-oxybenzoic acid Examples of the carboxylic acid include terephthalic acid. These difunctional aromatic carboxylic acids may be used alone or in combination of two or more. In addition to these difunctional aromatic carboxylic acids, difunctional aliphatic carboxylic acids such as adipic acid, azelaic acid, and sebacic acid; other acid components such as difunctional alicyclic carboxylic acids such as cyclohexanedicarboxylic acid You may use together 1 type (s) or 2 or more types. However, from the viewpoint that a thermoplastic polyester resin having excellent mechanical performance required for container applications can be obtained, 70 mol% or more of all the acid components used are difunctional aromatic carboxylic acids, especially terephthalic acid. Is desirable. As the ester-forming derivative of the bifunctional aromatic carboxylic acid, a lower alkyl ester of the bifunctional aromatic carboxylic acid can be used. Examples of ester-forming derivatives of difunctional aromatic carboxylic acids include lower alkyl esters such as dimethyl esters of aromatic dicarboxylic acids exemplified above; lower alkyl esters such as methyl esters of aromatic hydroxycarboxylic acids exemplified above. Examples thereof include esters.

As the diol compound, ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, nonamethylene glycol, 3-methylpentane-1,5-diol, 2-methyloctane- Aliphatic diols such as 1,8-diol and diethylene glycol; and alicyclic diols such as cyclohexanedimethanol. These diols may be used alone or in combination of two or more, but from the viewpoint of obtaining a thermoplastic polyester resin having excellent mechanical performance required for container applications, 70 of the diol compounds is obtained. It is desirable that the mol% or more is a linear alkylene glycol having 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol and hexamethylene glycol. An alkylene oxide such as ethylene oxide may be used as the diol compound.

As the raw material monomer for producing the thermoplastic polyester resin used in the present invention, generally, a bifunctional aromatic carboxylic acid or an ester-forming derivative thereof and a bifunctional compound such as a diol compound as described above are used. Mainly used, for example, triols such as glycerin and trimethylolpropane; tetraols such as pentaerythritol; tricarboxylic acids such as trimellitic acid and trimesic acid; trivalent or higher polyfunctional compounds such as tetracarboxylic acids such as pyromellitic acid The polymerizable compound can be used as a copolymerization component in an amount within a range that allows melt molding.

Although not particularly limited, in the production of the thermoplastic polyester resin used in the present invention, an operation according to a known method can be adopted.
For example, a desired dicarboxylic acid such as terephthalic acid may be directly esterified with a desired diol such as ethylene glycol, or an ester-forming derivative of a desired dicarboxylic acid such as a lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene. An ester of a dicarboxylic acid and a diol compound or a low polymer thereof is formed, which comprises transesterification with a desired diol such as glycol or by reacting a desired dicarboxylic acid with a desired alkylene oxide such as ethylene oxide. It can be carried out by a first stage reaction followed by a second stage reaction consisting of heating such a product under reduced pressure to polycondense until the desired degree of polymerization is reached.
A known catalyst can be used in these reactions. Examples of such catalysts include zinc acetate,
Zinc compounds such as zinc carbonate; manganese compounds such as manganese acetate and manganese carbonate; calcium compounds such as calcium acetate and calcium carbonate; cobalt compounds such as cobalt acetate and cobalt carbonate; transesterification such as barium compounds such as barium acetate and barium carbonate. Examples thereof include catalysts and antimony compounds such as antimony oxide, germanium compounds such as germanium oxide, and polycondensation catalysts such as titanium compounds such as tetraisopropyl orthotitanate.

If desired, the thermoplastic polyester resin may contain optional additives such as antioxidants, colorants,
An antistatic agent, a flame retardant, inorganic fine particles, a plasticizer, etc. can also be added.

The thermoplastic polyester resin used in the present invention has an intrinsic viscosity of 0.5 to 1.5 dl measured at 30 ° C. in a mixed solvent of equal weight of phenol and tetrachloroethane.
/ G is preferable, and it is 0.6-1.2d.
It is more preferably within the range of 1 / g. If the intrinsic viscosity is too low, the mechanical strength of the container obtained by molding may be low. On the other hand, if the intrinsic viscosity is too high, the melt viscosity may be too high, resulting in poor moldability into a container.

The polyester resin composition of the present invention contains the acrylic resin containing the structural unit represented by the general formula (I) in a specific ratio. The acrylic resin can exhibit ultraviolet absorbing performance due to the benzophenone structure contained in the above structural unit.

Examples of the lower alkyl group represented by R ¹ in the general formula (I) include a methyl group and an ethyl group, and a methyl group is preferable. Examples of the lower alkylene group represented by R ² include ethylene group, trimethylene group, tetramethylene group and propylene group, with ethylene group being preferred. Further, as the organic group represented by the substituent R ³ in the benzoyl group contained in the structural unit represented by the general formula (I),
Examples thereof include an alkyl group such as a methyl group, an ethyl group and a propyl group; an alkoxyl group such as a methoxyl group, an ethoxyl group and a propoxyl group; and a hydroxyl group. R ³ can be bonded at any position among the 5 positions consisting of 2 ortho positions, 2 meta positions and 1 para position in the benzoyl group, and n is 2 or 3 In the case of, it is needless to say that a plurality of R ³ 's should be bonded to different positions respectively. When n is 2 or 3, a plurality of R ^{3 s} may be the same organic group or different organic groups. However, it is preferable that n is 0, that is, the benzoyl group is unsubstituted.

In the present invention, the content of the structural unit represented by the general formula (I) in the acrylic resin is preferably 10% by weight or more from the viewpoint of high ultraviolet absorption performance and the like, and 20 to 90% by weight. It is more preferably within the range of%.

The acrylic resin may have a constitutional unit other than the constitutional unit represented by the general formula (I). In that case, as the constitutional unit other than the constitutional unit represented by the general formula (I), Is the following general formula (II) from the viewpoint of high thermal stability.

[0023]

[Chemical 3]

(In the formula, R ⁴ and R ⁵ each represent a lower alkyl group)

The structural unit represented by is preferred. here,
Examples of the lower alkyl group represented by R ⁴ and R ⁵ in the general formula (II) include a methyl group and an ethyl group.
A methyl group is preferred. The structural unit represented by the general formula (I) in the acrylic resin molecule and the general formula (II)
The arrangement mode of the structural unit represented by may be a random arrangement or a block arrangement. Particularly preferred acrylic resin in terms of high ultraviolet absorption performance, high thermal stability, ease of production, and the like, R ¹ in the general formula (I) is a methyl group, R ² is an ethylene group, and n is The structural unit corresponding to 0 and R ⁴ and R ⁵ in the above general formula (II)
In which each is a methyl group, a copolymer composed of structural units, that is, a copolymer composed of a 2-hydroxy-4- (2-methacryloyloxyethoxy) benzophenone unit and a methyl methacrylate unit.

When the acrylic resin of the present invention has a weight average molecular weight of 10,000 or more, it has a particularly high thermal stability in ultraviolet absorbing performance and tends to further suppress the elution from the polyester resin composition. On the other hand, when the weight average molecular weight is 150,000 or less, the compatibility with the thermoplastic polyester resin becomes particularly good, and the transparency of the container molded from the resulting polyester resin composition can be improved. . Therefore, the weight average molecular weight of the acrylic resin is preferably in the range of 10,000 to 150,000, and more preferably in the range of 20,000 to 80,000.

In the present invention, the composition ratio of the acrylic resin needs to be in the range of 0.01 to 10 parts by weight with respect to 100 parts by weight of the thermoplastic polyester resin. If the proportion of the acrylic resin is less than 0.01 parts by weight, the ultraviolet absorption performance of the obtained polyester resin composition will be insufficient. On the other hand, if it exceeds 10% by weight, the compatibility with the thermoplastic polyester resin decreases, and the transparency and mechanical strength of the container molded from the obtained polyester resin composition decrease. The composition ratio of the acrylic resin is 0.5 to 100 parts by weight of the thermoplastic polyester resin from the viewpoint of the ultraviolet absorption performance of the obtained polyester resin composition and the transparency and mechanical strength when the polyester resin composition is used in a container. It is preferably within the range of 5% by weight.

The method of blending the acrylic resin with the thermoplastic polyester resin for producing the polyester resin composition of the present invention is not particularly limited, and, for example, the polycondensation reaction in the production of the thermoplastic polyester resin described above can be performed. The acrylic resin can be added at any stage before or after completion, or at any stage before the completion of molding when molding the thermoplastic polyester resin. However, from the aspects of uniform mixing and work efficiency, a method of adding and kneading acrylic resin after the completion of the polycondensation reaction of thermoplastic polyester resin, a method of melting thermoplastic polyester resin chips and kneading acrylic resin into this, etc. It is preferable to produce a polyester resin composition chip. Further, a master chip in which an acrylic resin is mixed at a high concentration with a thermoplastic polyester resin is prepared and blended with another polyester resin chip at the time of molding to obtain a polyester resin composition of the present invention in which the acrylic resin is mixed in a predetermined amount. It is also possible.

The polyester resin composition of the present invention has an excellent ultraviolet absorbing performance, and the ultraviolet absorbing component is not extracted. The polyester resin composition of the present invention,
It can be melt-molded and thermoformed because it can retain its excellent UV absorption performance even after being exposed to high temperature conditions, and known molding methods such as injection molding method, blow molding method and biaxial stretching. A blow molding method, a vacuum molding method, a compression molding method, a direct blow molding method, or the like can be applied. Furthermore, the polyester resin composition of the present invention can exhibit the original transparency of the polyester resin. The polyester resin composition of the present invention can also be used by blending or laminating with other polymers.
For these reasons, the polyester resin composition of the present invention is extremely useful as a container material. The container made of the polyester resin composition of the present invention, as described above, the polyester resin composition, as in the usual thermoplastic polyester resin, injection molding method, blow molding method, biaxial stretch blow molding method, vacuum It can be produced by melt molding or thermoforming by any method such as molding method, compression molding method, direct blow molding method and the like. This container can block the transmission of ultraviolet rays, and since it does not extract ultraviolet-absorbing components, it deteriorates the contents of foods and drinks such as lactic acid drinks, edible oil, mirin, and salad dressings, and seasonings, due to ultraviolet rays. , It can prevent alteration and prevent the contents from being contaminated.

[0030]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Moreover, each physical-property value in an Example is a value obtained by measuring according to the following method.

(1) Ultraviolet Absorption Performance A polyester resin composition chip was prepared according to a conventional method.
A sheet with a thickness of 350 μm was formed by hot pressing at 280 ° C. and immediately thereafter with a water-cooling type cooling press, and the ultraviolet transmittance (%) at a wavelength of 390 μm of the obtained transparent sheet was manufactured by Shimadzu Corporation. It was measured with a UV-2100 type spectrophotometer, and this was used as an evaluation standard for ultraviolet absorption performance. It can be determined that the lower the ultraviolet transmittance is, the more excellent the ultraviolet absorbing performance is.

(2) Evaluation of UV-shielding performance as a container The obtained transparent bottle was filled with commercially available edible oil, sealed, left to stand in the direct sunlight for 2 months, and then the color tone of the edible oil was changed. Was evaluated. It can be determined that a container having a smaller change in color tone is a container having a better ultraviolet shielding performance.

Examples 1-3 864.5 g terephthalic acid and ethylene glycol 3
87.6 g was charged into an esterification reactor, and the temperature was 250 ° C.
The esterification reaction was carried out for 2 hours under a pressure of 2.5 kg / cm ² . Then, the obtained reaction product is preliminarily 250
The polycondensation reaction system was prepared by transferring to a polycondensator heated to 0 ° C., and adding 0.35 g of antimony trioxide and 0.11 g of phosphorous acid. While increasing the temperature of the polycondensation reaction system from 250 ° C to 280 ° C over 45 minutes, gradually increase the temperature by 0.1 m.
The pressure was reduced to mHg, and then polycondensation reaction was performed at 280 ° C. to produce polyethylene terephthalate having an intrinsic viscosity of 0.75 dl / g (measured value at 30 ° C. in an equal weight mixed solvent of phenol and tetrachloroethane). Nitrogen gas was sent to this system to return the pressure in the system to atmospheric pressure, and the acrylic resin was composed of 50% by weight of 2-hydroxy-4- (2-methacryloyloxyethoxy) benzophenone unit and 50% by weight of methyl methacrylate unit. A copolymer (weight average molecular weight 30,000) was added in an amount shown in Table 1, melt-kneaded in a nitrogen stream for 15 minutes, extruded into a strand, cut and cut to a length of 3.2 mm and a diameter of 2. An 8 mm cylindrical chip was obtained. Table 1 shows the evaluation results of the ultraviolet absorption performance of the obtained chip-shaped polyester resin composition.

Further, the obtained polyester resin composition is
By a conventional method, a preform was injection-molded at a cylinder temperature of 280 ° C., and the obtained preform had a surface temperature of 1
A transparent biaxially stretched blow bottle having an internal volume of about 1 liter was obtained by heating at 00 ° C. and then stretching and blowing. Table 1 shows the results of the ultraviolet ray shielding performance evaluation of the obtained bottles. After the ultraviolet shielding performance evaluation test of the bottle, the edible oil collected was analyzed, but no acrylic resin leaching into the edible oil was observed.

Example 4 In Example 1, instead of 864.5 g of terephthalic acid, 821.3 g of terephthalic acid and 43.2 g of isophthalic acid were used.
A corresponding polyester resin composition and a transparent bottle were obtained in the same manner except that the mixture of was used. Table 1 shows the evaluation results of the obtained polyester resin composition and bottle. In the ultraviolet shielding performance evaluation test of the bottle,
No elution of acrylic resin into edible oil was observed.

Example 5 The same procedure as in Example 1 was repeated except that a mixture of 371.4 g of ethylene glycol and 37.5 g of 1,4-cyclohexanedimethanol was used instead of 387.6 g of ethylene glycol. A composition and a clear bottle were obtained. Table 1 shows the evaluation results of the obtained polyester resin composition and bottle. In the ultraviolet shielding performance evaluation test of the bottle, no elution of the acrylic resin into the cooking oil was observed.

Example 6 In Example 1, as an acrylic resin, a copolymer of 30% by weight of 2-hydroxy-4- (2-methacryloyloxyethoxy) benzophenone unit and 70% by weight of methyl methacrylate unit (weight average molecular weight) 35,000
A corresponding polyester resin composition and a transparent bottle were obtained in the same manner except that 0) was used. Table 1 shows the evaluation results of the obtained polyester resin composition and bottle. In the ultraviolet shielding performance evaluation test of the bottle, no elution of the acrylic resin into the cooking oil was observed.

Comparative Example 1 A polyester resin and a transparent bottle were obtained in the same manner as in Example 1 except that the acrylic resin was not used. Table 1 shows the evaluation results of the obtained polyester resin and bottle.
Shown in.

Comparative Example 2 A corresponding polyester resin composition and a transparent bottle were obtained in the same manner as in Example 1, except that the amount of acrylic resin added was changed to the amount shown in Table 1. Table 1 shows the evaluation results of the obtained polyester resin composition and bottle. In the ultraviolet shielding performance evaluation test of the bottle, no elution of the acrylic resin into the cooking oil was observed.

Comparative Example 3 A corresponding polyester resin composition was obtained in the same manner as in Example 1 except that the amount of acrylic resin added was changed to the amount shown in Table 1. Using the obtained polyester resin composition, a sheet for evaluating ultraviolet absorption performance was molded and a bottle was molded according to the method of Example 1, but in any case, only a significantly clouded molded product was obtained.

Comparative Example 4 In Example 1, 2- [2, which is known as a benzotriazole type ultraviolet absorber, is used instead of the acrylic resin.
-Hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole (Tinuvin 234 manufactured by Ciba-Geigy) was used in the same manner except that the amounts shown in Table 1 were used. A polyester resin composition and a transparent bottle were obtained. Table 1 shows the evaluation results of the obtained polyester resin composition and bottle. In the ultraviolet shielding performance evaluation test of the bottle, it was found that the ultraviolet absorber was dissolved in the edible oil.

[0042]

[Table 1]

In Table 1, in the "Evaluation of UV shielding performance of bottles", "○" means that no change in the color tone of the edible oil was observed in the UV shielding performance evaluation test, and "X" was the same. Indicates that a change in the color tone of the edible oil was observed in the test.

[0044]

EFFECTS OF THE INVENTION According to the present invention, as is clear from the above-mentioned examples, it has an excellent ultraviolet absorbing performance, and its excellent ultraviolet absorbing performance even after being exposed to high temperature conditions such as melt molding. There is provided a polyester resin composition capable of retaining the above properties, not extracting the ultraviolet absorbing component, and exhibiting the original transparency of the polyester resin. The container of the present invention effectively exhibits the characteristics derived from these polyester resin compositions, and even in the case of a transparent container, the contents can be protected from the adverse effects of ultraviolet rays, and the contents are contaminated. Nothing.

Claims (2)

[Claims] 1. 100 parts by weight of a thermoplastic polyester resin and the following general formula (I): (Wherein R ¹ represents a lower alkyl group, R ² represents a lower alkylene group, R ³ represents an organic group, and n represents an integer of 0 to 3). A polyester resin composition comprising 0.01 to 10 parts by weight. 2. A container made of the polyester resin composition according to claim 1.