JP2000212416A - Polyester resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester resin molded product having an excellent ultraviolet absorbing effect and weatherability, by improving the dispersibility of an inorganic, ultraviolet absorber to be blended in a polyester resin. SOLUTION: A polyester resin molded product, comprising a polyester resin composition in which a thermoplastic polyester resin is blended with an inorganic, ultraviolet absorber having an ultraviolet absorbing effect and with a resin-based pigment dispersant that is a carboxylic acid-modified product or a styrene-modified product of a polyethylene, polypropylene, or ethylene/ propylene copolymer an that has a molecular weight by a viscosity method of 500-10,000, in such a ratio R of the resin-based pigment dispersant to the inorganic, ultraviolet absorber (R = an addition amount of the resin-based pigment dispersant/an addition amount of the inorganic, ultraviolet absorber) as to be 0.1<=R<=5, is characterized in that a light transmittance thereof is 0-10% at a wave length of 360 nm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin molded article having an ultraviolet absorbing effect and excellent weather resistance.

[0002]

2. Description of the Related Art Conventionally, plastic molded products include packaging materials typified by containers for foods, beverages, toiletries and cosmetics, as well as mechanical materials, electric and electronic materials, optical materials, building materials, and the like. Used in a wide range of fields. These plastic molded articles may be added with various additives in order to impart functionality according to the purpose of use, and examples thereof include ultraviolet absorbers.

[0003] Ultraviolet light refers to electromagnetic waves having a wavelength of 100 to 400 nm, and the energy of light in this region is C, H,
O binding energy (70-110 kcal / mol)
It has the same energy as. Therefore, mainly C,
A plastic molded article composed of a bond of H and O may break the bond when irradiated with ultraviolet rays, resulting in deterioration of the resin, discoloration, and reduction in mechanical strength. On the other hand, not only plastic molded articles, but also contents to be filled into packaging materials, especially toiletries and cosmetics, may be accompanied by discoloration, deterioration, and decomposition of drugs due to irradiation of ultraviolet rays.

[0004] In order to solve such problems, the above-mentioned inorganic ultraviolet absorber is blended into a plastic molded product. Generally, organic UV absorbing materials are often used as UV absorbing materials, and as typical examples thereof,
Phenyl salicylate, 2-hydroxy-4methoxybenzophenone, and 2 (2'-hydroxy-5methylphenyl) benzotriazole. The organic ultraviolet absorbing material can impart transparency and ultraviolet absorbing ability by being kneaded into a plastic molded product.

However, organic UV absorbing materials are
There is a problem that the molded product is colored due to the ultraviolet absorption mechanism. In the case of plastic molded articles, this problem of coloring is accompanied by poor appearance, and it is desirable to avoid this problem as much as possible. Therefore, cases of using inorganic ultraviolet absorbing materials instead of these organic ultraviolet absorbing materials have been increasing. Typical examples thereof include zinc oxide, titanium oxide, cerium oxide, iron oxide and the like.

When such an inorganic ultraviolet absorber absorbs ultraviolet rays, electrons are generated in the conduction band of the inorganic ultraviolet absorber and holes are generated in the valence band. Some of these move to the surface of the inorganic ultraviolet absorber and form .OH or .OH by oxygen, moisture, heat, or the like. These radicals break down the resin
It causes deterioration (photocatalytic activity). This means that if a molded article containing an inorganic UV absorber is stored for a long time under UV irradiation, the resin will be decomposed due to photocatalytic activity.
Deterioration occurs, causing remarkable discoloration (yellowing) and a decrease in mechanical strength due to a decrease in molecular weight.

As described above, due to the photocatalytic activity of the inorganic ultraviolet absorber, there is a possibility that the processability and the physical properties of the resin composition are significantly reduced. In order to reduce the photocatalytic activity of such an inorganic ultraviolet absorber, the surface of the inorganic ultraviolet absorber is treated with silica, alumina or the like, an inorganic ultraviolet absorber, an aliphatic carboxylic acid or a metal salt or ester thereof, Alternatively, a prescription for surface treatment with silicone or the like is used. However, such a surface treatment results in increasing the material cost of the inorganic UV absorber.

In general, the surface tension of an inorganic ultraviolet absorber is smaller than that of plastic, and the interaction between the inorganic ultraviolet absorber and the plastic is originally low. Is added, the primary particles composed of ultrafine particles of the order of nm are aggregated, and the dispersed particles are dispersed in the plastic in the form of secondary particles having a diameter of several μm to several tens μm. Such a decrease in dispersibility may make the resin brittle, and may result in poor impact resistance when formed into a molded article. Also, that the secondary aggregated particles are dispersed,
This means that a larger amount of the inorganic ultraviolet absorber is added than the amount at which the effect of adding the inorganic ultraviolet absorber is obtained, and as a result, the cost is increased.

To summarize the above contents, it is actually desirable to use an inorganic ultraviolet absorber in terms of safety and an ultraviolet absorbing effect, and in consideration of the protective property of the contents, the light transmittance of the molded article is not considered. At present, it is desired to obtain a polyester resin molded product having a transmittance at a wavelength of 360 nm or less of 0 to 10% and further improving the weather resistance and the dispersibility of an inorganic ultraviolet absorber.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to take into consideration the above-mentioned situation, and to improve the dispersibility of an inorganic ultraviolet absorber incorporated in a polyester resin.
An object of the present invention is to provide a polyester resin molded article having an excellent ultraviolet absorbing effect and weather resistance.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been conceived to solve the above-mentioned problems, and the invention according to claim 1 is directed to an inorganic ultraviolet having an ultraviolet absorbing effect on a thermoplastic polyester resin. Absorbent, and polyethylene,
Polypropylene or a carboxylic acid-modified or styrene-modified ethylene-propylene copolymer having a molecular weight of 500 to 10,000 in a viscosity method, a resin-based pigment dispersant and an inorganic ultraviolet absorber A polyester resin composition comprising a polyester resin composition blended in a ratio R (R = addition amount of resin-based pigment dispersant / addition amount of inorganic ultraviolet absorber) of 0.1 ≦ R ≦ 5, A polyester resin molded article having a light transmittance of 0 to 10% at a wavelength of 360 nm or less.

An invention according to claim 2 is an inorganic ultraviolet absorber having an ultraviolet absorbing effect on a thermoplastic polyester resin, and a carboxylic acid-modified or styrene-modified polyethylene, polypropylene or ethylene-propylene copolymer. And a resin pigment dispersant having a molecular weight of 500 to 10000 in the viscosity method is prepared by adding a ratio R of the resin pigment dispersant to the inorganic ultraviolet absorber (R = addition amount of the resin pigment dispersant / inorganic ultraviolet absorber) Agent addition amount).
A polyester resin molded article containing at least one layer of a polyester resin composition blended so that 1 ≦ R ≦ 5, wherein the light transmittance is 0 to 360 nm or less.
10% of a polyester resin molded article.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
Wherein the inorganic ultraviolet absorbent is any one of zinc oxide and titanium oxide, or a mixture thereof.

The invention described in claim 4 is the first or second invention.
Wherein the acid component of the thermoplastic polyester resin is selected from at least one of terephthalic acid, isophthalic acid, naphthalene 2,6-dicarboxylic acid, succinic acid, adipic acid, succinic acid, and sebacic acid. Molded article.

The invention according to claim 5 is the first or second invention.
Wherein the diol component of the thermoplastic polyester resin is a glycol such as ethylene glycol, propylene glycol, butylene glycol, 1,4-cyclohexane dimethanol, or a polyoxyalkylene glycol such as polyethylene glycol, polypropylene glycol, or polytetramethylene glycol. And a polyester resin molded article characterized by being selected from at least one or more of the following.

The invention according to claim 6 is the first or second invention.
In the description, the thermoplastic polyester resin is a oxyacid polymer or a polyester resin molded article comprising an oxyacid copolymer.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS This will be described in detail below. As the base resin constituting the polyester resin molded article in the present invention, the acid component is terephthalic acid, isophthalic acid,
At least one or more of naphthalene 2,6-dicarboxylic acid, succinic acid, adipic acid, succinic acid, and sebacic acid, and further, the diol component is glycols such as ethylene glycol, propylene glycol, butylene glycol, and 1,4-cyclohexanedimethanol. Alternatively, at least one kind of polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol is polymerized. Further, as other acid components, diphenyl sulfone dicarboxylic acid, hexahydroterephthalic acid,
Hexahydroisophthalic acid, azelaic acid, etc. can be selected, and the diol component is neopentyl glycol,
Examples thereof include diethylene glycol, 1,4-cyclohexane dimethylol, 2,2-bis (4-β-hydroxyethoxyphenyl) propane, and 1,4-bis (β-hydroxyethoxy) benzene.

In addition to the polyester resins other than those described above, a polyester resin comprising a polymer of an oxyacid or a copolymer of an oxyacid may be used. As the oxyacid, lactic acid, ε-caprolactone, p-oxybenzoic acid, p
Various selections can be made, such as -β-hydroxyethoxybenzoic acid.

Representative examples of the polyester resins described above include aromatic polyester resins such as polyethylene terephthalate resin and polyethylene naphthalate resin, aliphatic polyester resins such as polyethylene succinate resin and polybutylene succinate resin, and the like. Oxyacid polymers such as polylactic acid resins and polycaprolactone resins, or polyester elastomers obtained by copolymerizing aromatic polyester with polyoxyalkylene glycol can also be used. Further, these polyester resins may be used alone or as a blend, if necessary.

The inorganic UV absorber having an ultraviolet absorbing effect in the polyester resin composition of the present invention includes:
Examples include zinc oxide, titanium oxide, cerium oxide, and iron oxide. However, iron oxide turns slightly red to absorb light in the visible light range.
Cerium oxide has a lower ultraviolet absorbing effect than zinc oxide, and therefore zinc oxide is preferred as an inorganic ultraviolet absorber. The average primary particle diameter of the inorganic ultraviolet absorbent represented by zinc oxide is preferably 10 to 100 nm in consideration of the blending with the polyester resin and the ultraviolet absorbing effect.

Examples of the resin-based pigment dispersant added to the above-described polyester resin include olefin-based copolymers. As these olefin-based copolymers, a carboxylic acid-modified product of any of polyethylene, polypropylene, and ethylene-propylene copolymer is preferable. These copolymers may be used alone or as a mixture. Various kinds of carboxylic acids such as monocarboxylic acids such as acrylic acid and methacrylic acid, and dicarboxylic acids such as maleic anhydride and itaconic acid can be used. The amount of modification with these carboxylic acids is not particularly limited.
An acid value (KOHmg / g) according to SK5902 of 20 to
60, 1 to 10 wt% by weight of the copolymer is used. In addition to the carboxylic acid-modified product, an olefin-based copolymer obtained by copolymerizing a component such as styrene may be used.
The styrene content at this time is preferably 1 to 40% by weight. Further, those dispersants having a value of 500 to 10,000 as measured by a viscosity method are used to improve the dispersibility of the inorganic ultraviolet absorbent.

The above-mentioned polyethylene, polypropylene, and ethylene-propylene copolymers modified with carboxylic acid or styrene are melt-kneaded together with the inorganic ultraviolet absorber incorporated in the polyester resin to obtain a dispersed state of the inorganic ultraviolet absorber. Is improved. In addition, since these resin-based pigment dispersants cover the surface of the inorganic ultraviolet absorber, the photocatalytic activity can be suppressed. That is, it is possible to improve the dispersibility of the inorganic ultraviolet absorber and the weather resistance of the molded article by blending these resin pigment dispersants.

The amount of the inorganic ultraviolet absorbent added to the polyester resin is such that the transmittance at a wavelength of 360 nm or less is 0 to 10%, more preferably 0 to 5%, and still more preferably the light transmittance as a molded article. Since it is desired to be 0% to 1%, it is possible to set the addition amount according to the transmittance. Generally, polyester resin 1
Setting the amount in the range of 0.01 to 5.00 parts by weight with respect to 00 parts by weight is preferable in terms of the ultraviolet absorbing effect and the dispersibility of the inorganic ultraviolet absorbing agent, but is not particularly limited.

The addition amount of the resin-based pigment dispersant is determined by the ratio of the addition amount of the resin-based pigment dispersant to the addition amount of the inorganic ultraviolet absorber (R = the addition amount of the resin-based pigment dispersant / the addition amount of the inorganic ultraviolet-absorbing material). ) Is 0.1 ≦ R ≦ 5. When R <0.1 (when the amount of the resin-based pigment dispersant is small), the dispersibility of the inorganic ultraviolet absorber decreases. Further, even when R> 5 (when the amount of the resin-based pigment dispersant is large), the dispersibility may be reduced. In particular, by setting the range of 0.5 ≦ R ≦ 1, it is possible to obtain a polyester resin molded article in which the dispersion state of the inorganic ultraviolet absorbent is favorable.

As described above, the dispersion state of the inorganic ultraviolet absorbent may affect the strength properties of the polyester resin molded article. Therefore, as for the dispersion state of the inorganic ultraviolet absorbent at least in the polyester resin molded product, the smaller the amount of the inorganic ultraviolet absorbent dispersed in the order of μm, the smaller is preferable. Maximum particle size of inorganic UV absorber dispersed in polyester resin molded product is 5μ
m, preferably 1 μm or less, more preferably 50 μm or less.
0 nm or less is preferable.

The method for producing a polyester resin molded article of the present invention is carried out by melt-kneading the polyester resin described above, a predetermined amount of an inorganic ultraviolet absorber and a resin pigment dispersant. When these compositions are melt-kneaded, various kneaders such as a single-screw extruder, a twin-screw extruder, or a Brabender-type kneader can be used. The molten resin kneaded using these kneaders is extruded into strands, and the polyester resin composition cooled by water cooling or air cooling and then pelletized is subjected to various molding methods such as injection molding, blow molding, stretch blow molding, and extrusion molding. Utilizing it to obtain a polyester resin molded article. At that time, a high-concentration dispersion in which the inorganic ultraviolet absorber was dispersed at a high concentration in advance was prepared, and by using this high-concentration dispersion as a master batch, the inorganic ultraviolet absorber was in the range of 0.01 to It is also possible to obtain a molded body of 5.00 parts by weight.

As the development of the polyester resin molded article,
In addition to the plates described above, films, sheets, bottles,
Various forms such as trays are possible. If it is a film, by a method such as inflation or extrusion lamination,
For a sheet, extrusion molding or extrusion laminating is used. For a bottle, injection molding, (stretching) blow molding,
By using a molding method such as injection blow molding, a sheet molded product can be formed on a tray by a technique such as vacuum compression molding. In addition to these molded articles, various polyester resin molded articles can be obtained. These polyester resin molded articles may contain additives such as a coloring agent as needed. In addition, these polyester resin molded articles are not only a single layer of the polyester resin composition, but also a polyester resin composition of a multilayer molded article.
It is also possible to use it as a layer.

[0028]

Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1 A polyethylene terephthalate resin (described as PET in the table) was used as a thermoplastic polyester resin, and an average primary particle diameter of 2 was used as an inorganic ultraviolet absorber.
0 nm zinc oxide as a resin-based pigment dispersant with a molecular weight of 1
A maleic anhydride modified product of 600 ethylene-propylene copolymer was used. At this time, the amount of zinc oxide added was 0.1.
8 parts by weight, the ratio R of the added amount of the resinous pigment dispersant and zinc oxide
1 was set to R = 0.8. This mixture of the inorganic ultraviolet absorber and the resin pigment dispersant was added to the polyethylene terephthalate resin in a molten state. A twin screw extruder was used for these kneading. The molten resin extruded by the twin-screw extruder was cooled with water, pelletized and dried to prepare a polyester resin composition. Using this polyester resin composition, 100 mm x 1 with a thickness of 2 mm by injection molding.
A 00 mm polyester resin molded product (plate) was prepared. The light transmittance of this plate is measured by a spectrophotometer.
The weather resistance was evaluated using a weather resistance tester. The evaluation was performed sensually by visually observing the yellowing of the plate before and after the weather resistance test. The dispersion state of zinc oxide was observed with a scanning electron microscope (SEM). Table 1 shows the results.

Example 2 Example 1 was the same as Example 1 except that the amount of zinc oxide added was 0.5 part by weight and the resin-based pigment dispersant was styrene-modified polyethylene having a molecular weight of 2100.

Example 3 Example 1 was repeated except that a copolyester resin obtained by copolymerizing 1,4-cyclohexanedimethanol with a polyethylene terephthalate resin (described as copolyester in the table) was used as the thermoplastic polyester resin.
Is the same as

Example 4 Example 4 was the same as Example 1 except that a polyethylene naphthalate resin (described as PEN in the table) was used as the thermoplastic polyester resin.

Example 5 Example 5 was the same as Example 1 except that a polybutylene succinate resin (described as PBSU in the table) was used as the thermoplastic polyester resin.

Example 6 Example 6 is the same as Example 1 except that polycaprolactone (described as PCL in the table), which is a polymer of oxyacid, was used as the thermoplastic polyester resin. Example 1 except that the addition amount of zinc oxide was changed to 5 parts by weight.
Is the same as

<Example 7> Of the polyester resin composition prepared in Example 1, the amount of zinc oxide added was 5 parts by weight, and the average thickness was 0.8 by stretch blow molding.
It is the same as Example 1 except that a stretch blow bottle having a length of 2 mm was formed.

Example 8 The same as Example 6 except that the amount of zinc oxide added was 5 parts by weight and the ratio R to the amount of dispersant added was 1 in the polyester resin composition prepared in Example 1. is there.

Example 9 A sheet having a thickness of 0.1 mm was formed by extrusion using the polyester resin composition prepared in Example 1 with the addition amount of zinc oxide being 5 parts by weight. . This is the same as Example 1 except that the sheet was formed into a tray by vacuum compression molding.

<Comparative Example 1> The same as Example 1 except that no inorganic ultraviolet absorber and resin pigment dispersant were added.

<Comparative Example 2> The same as Example 1 except that no resin-based pigment dispersant was used.

Comparative Example 3 A low molecular weight ethylene-propylene copolymer wax (molecular weight: 400
This example is the same as Example 1 except that 0) was set.

<Comparative Example 4> The same as Example 1 except that the ratio R of zinc oxide and the amount of the resin-based pigment dispersant added was R = 10.

[0042]

[Table 1]

The following can be said from these results. Various polyester resins are blended with an inorganic UV absorber, a carboxylic acid or styrene-modified olefin copolymer is used as the resin pigment dispersant, and the ratio R of the resin pigment dispersant to the inorganic UV absorber is R Is 0.1 to 5, the light transmittance at 360 nm or less is 0 to 10%, and the weather resistance is excellent by suppressing the photocatalytic activity of zinc oxide, and the dispersibility of zinc oxide is improved. It is possible to obtain an improved polyester resin molded article. Further, as shown in Comparative Examples 1 to 4, it was found that when no inorganic ultraviolet absorber was added, the transmittance in the ultraviolet region was high, and as a result, yellowing occurred in the weather resistance test. Further, it can be seen that when no pigment dispersant is added, the molded product is significantly yellowed due to photocatalytic activity, and when the type of dispersant is changed, the dispersibility of zinc oxide is reduced. Further, it is found that the dispersibility of zinc oxide is significantly reduced even when the ratio between the amount of the resin pigment dispersant added and the amount of zinc oxide added is too large. This time, zinc oxide was mainly used, but other inorganic UV absorbers can also be used.

[0044]

The polyester resin molded article using the polyester resin composition of the present invention is an excellent alternative to conventional organic ultraviolet absorbers which are problematic in terms of coloring, hygiene, durability of the ultraviolet absorbing effect, and heat resistance. It is a polyester resin molding having excellent weather resistance while having an ultraviolet absorbing effect, and can be applied to bottles, plates, films or laminates, trays and the like.

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Claims (6)

[Claims] 1. An inorganic ultraviolet absorbent having an ultraviolet absorbing effect on a thermoplastic polyester resin, and a carboxylic acid-modified or styrene-modified polyethylene, polypropylene or ethylene-propylene copolymer, which is obtained by a viscosity method. Of the resin-based pigment dispersant having a molecular weight of 500 to 10000 in the ratio R of the resin-based pigment dispersant and the inorganic ultraviolet absorber (R = added amount of the resin-based pigment dispersant / added amount of the inorganic ultraviolet absorber) A polyester resin molded article comprising a polyester resin composition blended so that 1 ≦ R ≦ 5, wherein the light transmittance of the polyester resin composition is 360 n
m and 0 to 10% of a polyester resin molded product. 2. An inorganic ultraviolet absorbent having an ultraviolet absorbing effect on a thermoplastic polyester resin, and a carboxylic acid-modified or styrene-modified polyethylene, polypropylene or ethylene-propylene copolymer, which is obtained by a viscosity method. Of the resin-based pigment dispersant having a molecular weight of 500 to 10000 in the ratio R of the resin-based pigment dispersant and the inorganic ultraviolet absorber (R = added amount of the resin-based pigment dispersant / added amount of the inorganic ultraviolet absorber) A polyester resin molded article comprising at least one layer of a polyester resin composition blended so that 1 ≦ R ≦ 5, wherein the light transmittance is 0 to 10% at a wavelength of 360 nm or less. Polyester resin molded product. 3. The polyester resin molded article according to claim 1, wherein the inorganic ultraviolet absorbent is one of zinc oxide and titanium oxide, or a mixture thereof. 4. The thermoplastic polyester resin according to claim 1, wherein the acid component of the thermoplastic polyester resin is terephthalic acid, isophthalic acid,
A polyester resin molded product selected from at least one of naphthalene 2,6-dicarboxylic acid, succinic acid, adipic acid, succinic acid, and sebacic acid. 5. The thermoplastic polyester resin according to claim 1, wherein the diol component of the thermoplastic polyester resin is ethylene glycol,
Propylene glycol, butylene glycol, 1,4-
A polyester resin molded article selected from at least one of glycols such as cyclohexanedimethanol and polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol. 6. A polyester resin molded article according to claim 1, wherein the thermoplastic polyester resin comprises a polymer of oxyacid or a copolymer of oxyacid.