JPH04239528A - Film, sheet and blow molded body excellent in transparency and weather resistance - Google Patents

Abstract

PURPOSE:To provide a film, a sheet and a blow molded body excellent in weather resistance by adding a small amount of a polyalkylene naphthalate to a thermoplastic resin such as a polycarbonate (PC) or polyethylene terephthalate (PET) excellent in transparency. CONSTITUTION:A film, a sheet and a blow molded body are obtained by adding >=0.02 to <0.2wt.% polyalkylene naphthalate to a thermoplastic resin such as PC or PET excellent in transparency, providing a composition excellent in the transparency and forming the resultant composition.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to films and sheets having excellent transparency and weather resistance, and to blow molded articles. More specifically, the present invention relates to films and sheets with excellent transparency and weather resistance, and blow molded articles that can be effectively used as packaging materials used outdoors for long periods of time and various industrial materials.

0002

[Prior art] Polycarbonate (hereinafter sometimes abbreviated as PC) and polyethylene terephthalate (hereinafter PET)
Films, sheets, or hollow molded bodies made of highly transparent thermoplastic resins such as (sometimes abbreviated as ) are widely used as packaging materials and various industrial materials; In this case, the original characteristic of colorless transparency is often impaired, for example, the hue changes.

[0003] To date, organic and inorganic ultraviolet absorbers have been developed to solve these problems.
Attempts have also been made to apply these ultraviolet absorbers to thermoplastic resins with excellent transparency. However, when thermoplastic resins containing ultraviolet absorbers are used, for example, in food packaging containers, there is a risk of problems such as toxicity and changes in taste and odor due to migration into the contents. In addition, it is difficult to accurately determine the color of the contents due to the coloring of the container, and it is difficult to distinguish the deterioration of the contents due to changes in color. There are disadvantages such as no

Under these circumstances, it has been desired to effectively impart weather resistance to films, sheets, and blow molded bodies made of thermoplastic resins having excellent colorless transparency.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide films, sheets, and blow molded articles made of thermoplastic resins having excellent transparency and weather resistance.

Another object of the present invention is to provide films, sheets and blow molded articles having excellent transparency and weather resistance that can withstand long-term outdoor use.

Further objects and advantages of the invention will become apparent from the following description.

[0008]

[Means for Solving the Problems] As a result of intensive studies to overcome the problems of the prior art, the present inventor has solved the above problems by adding a small amount of polyalkylene naphthalate to a thermoplastic resin with excellent transparency. We have discovered that it is possible to solve the problem, and have arrived at the present invention.

That is, according to the present invention, the thermoplastic resin contains a highly transparent thermoplastic resin and a polyalkylene naphthalate resin, and the thermoplastic resin accounts for 99.8% by weight based on the total weight of both resins. exceeding 99.98% by weight
and the polyalkylene naphthalate resin is 0
．． Provided is a film or sheet or a blow molded article having excellent transparency and weather resistance, characterized by a content of 0.02% by weight or more and less than 0.2% by weight.

Preferred examples of the thermoplastic resin having excellent transparency used in the present invention include polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polysulfone, and polystyrene.

Further, the polyalkylene naphthalate used in the present invention mainly consists of naphthalene dicarboxylic acid groups and alkylene glycol groups.

That is, in addition to polymers consisting only of naphthalene dicarboxylic acid groups and alkylene glycol groups, other naphthalene dicarboxylic acid groups can be used, such as terephthalic acid, isophthalic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, and diphenyl ether. other aromatic dicarboxylic acids such as dicarboxylic acid, diphenylsulfone dicarboxylic acid, etc.; alicyclic dicarboxylic acids such as hexahydroterephthalic acid, hexahydroisophthalic acid, etc.; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, etc. ; 5% by weight by substitution with one or more other difunctional carboxylic acids such as oxyacids such as p-β-hydroxyethoxybenzoic acid, ε-oxycaproic acid, etc.;
Copolymers prepared by copolymerizing the following compounds can also be used as the polyalkylene naphthalate in the present invention.

[0013] As the naphthalenedicarboxylic acid, 2,6
-Naphthalene dicarboxylic acid is preferably used. 2,
7-, 1,5-, 1,6-, 1,7- and other naphthalene dicarboxylic acid isomers can be used similarly.

[0014] As the alkylene glycol, ethylene glycol and/or butylene glycol are preferably used. In addition to these, examples include trimethylene glycol, decamethylene glycol, neopentyl glycol, diethylene glycol, 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2
,2-bis(4'-β-hydroxyethoxyphenyl)
Copolymerization by substituting a portion of ethylene glycol and/or butylene glycol with one or more other polyfunctional compounds such as propane and bis(4'-β-hydroxyethoxyphenyl)sulfonic acid in a range of up to 5% by weight. Copolymers that are made of acetate are also advantageously used as polyalkylene naphthalates in the present invention.

As the polyalkylene naphthalate, for example, polyethylene 2,6-naphthalate and polybutylene 2,6-naphthalate are preferably used. Also,
The molecular weight of the polyalkylene naphthalate is preferably one in which the intrinsic viscosity (hereinafter sometimes abbreviated as IV) measured at 35°C using orthochlorophenol as a solvent is in the range of 0.3 to 1.5. More preferably, it is in the range of .4 to 0.8.

In the present invention, polyalkylene naphthalate is used in an amount of 0.02% by weight or more and less than 0.2% by weight, preferably 0.03% by weight or more and less than 0.2% by weight. If it is less than 0.02% by weight, the effect of improving weather resistance (discoloration resistance) will be small, and if it is more than 0.2% by weight, the film, sheet, or hollow molded article will be susceptible to discoloration.

[0017] When producing the films, sheets, and blow molded bodies of the present invention, a thermoplastic resin having excellent transparency and polyalkylene naphthalate are melt-mixed in advance. That is, both resins are melted in advance in a molding machine or extruder,
mixed. Mixing is performed, for example, by kneading using a screw or static mixer.

For example, there is a method in which a highly transparent thermoplastic resin and polyalkylene naphthalate are mixed in the form of chips and then fed into a molding machine or an extruder for mixing, or a method in which both types of polymers are mixed in an extruder or melt-mixed. This method involves melting and mixing using a tank or the like. By these methods, a mixed resin composition in the form of chips can be obtained, which can be advantageously used to form films, sheets, or hollow molded bodies.

Conventional methods are used to prepare the films and sheets of this invention. For example, it can be obtained by melting it using a conventional extruder, passing it through a die to form a film or sheet, and casting it onto a cooling drum.

[0020] Hollow molded objects such as cups and trays may be produced using a female mold or a thermoforming method using a female mold together with a male mold (in some cases, a plug), such as a vacuum forming method, a pressure forming method, or a vacuum pressure forming method. laws etc. are used.

Furthermore, the hollow molded article of the present invention can be advantageously produced by a general molding method, such as an injection blow method, an oriented blow method, an extrusion blow method, or the like. To give a suitable example of the injection blow method, first, a polymer is melted, the polymer is injected into a cavity formed by an injection core and an injection mold to form a preform, and the injection core and preform are blown. It is introduced into a mold and blown into a hollow molded body. The temperature of the molten polymer at this time is preferably above the softening point of the polymer and below 380°C, especially between 250°C and 380°C.
360°C is more preferred. The temperature of the injection core is preferably -30°C to 170°C, more preferably 0°C to 15°C.
It is 0°C. The time for cooling the preform by contacting the polymer with the injection mold is preferably from 1 to 30 seconds, particularly preferably from 2 to 15 seconds.

[0022] The time for contacting the blowing mold with the polymer and cooling the container is preferably 1 to 30 seconds, especially 2 seconds.
~15 seconds is more preferred. Although either gas or liquid may be used for blowing, gas is easier to use.

[0023] As a suitable example of the oriented blowing method, the polymer is made into a hollow cylindrical amorphous molded article with an appropriate shape (for example, length 10 cm, inner diameter 1 cm, outer diameter 1.8 cm), and the polymer is Above the glass transition point (Tg) of 190℃
Preheat the container to an average of about 1.5-16
Extend it to about double the length. Note that the container can be heat-treated as appropriate.

A suitable extrusion blow method involves first melting the polymer to form a parison of appropriate thickness, sealing the bottom of the parison, and forming the required shape, eg -
Blow molding is performed by blowing gas or liquid into the mold so as to contact the mold at a temperature of about 30 to 170°C.

[0025]

[Effect of the invention] The film, sheet or hollow molded product of the present invention thus obtained has transparency and weather resistance (colorfastness).
It is excellent.

[0026]

[Examples] The present invention will be explained in detail with reference to Examples below.
The main physical property measurement methods and test methods are as follows.

(1) Haze: manufactured by Mitsubishi Kasei Corporation, SEP
- Measured using a DI type Poick integrating sphere light transmittance meter.

(2) Hue: Measured using a color difference meter CR-100 manufactured by Minolta Co., Ltd.

(3) Weather resistance test: A 500 hour exposure test was conducted using Sunshine Super Long Life Weather Meter WEL-SUN-DC manufactured by Suga Test Instruments Co., Ltd.

(4) IV: Polyalkylene naphthalate was measured at 35°C using orthochlorophenol as a solvent.

Polycarbonate was measured at 20°C using methylene chloride as a solvent.

Examples 1 and 2 and Comparative Examples 1 and 2IV0.6
5 polycarbonate (poly 4,4'-dioxydiphenyl 2,2-propane carbonate, hereinafter abbreviated as PC) and polyethylene 2,6-naphthalate (hereinafter abbreviated as PEN) of IV 0.70 were blended in the form of chips. .

Thereafter, the mixture was dried with hot air at 130° C. for 5 hours, then fed into an extruder, extruded through a die into a film, and cast onto a cooling drum to obtain a film.

A weather resistance test was conducted on the film. The results obtained are shown in Table 1.

[0035]

[Table 1]

Examples 3 and 4 and Comparative Examples 3 and 4 IV0.9
0 polyethylene terephthalate (hereinafter abbreviated as PET)
and polybutylene 2,6-naphthalate with IV 0.65 (
(hereinafter abbreviated as PBN) are mixed in the form of chips,
It was dried with hot air at 160°C for 3 hours. Thereafter, melt blending was performed using a TEX44S twin-screw extruder manufactured by Japan Steel Works, Ltd. at a cylinder temperature of 320° C. and a screw rotation speed of 120 rpm. After melt-blending, the mixture was discharged from the outlet of the twin-screw extruder, which was rapidly cooled with cooling water, and cut into chips with a diameter and length of approximately 3 mm using a cutter.

After drying this chip with hot air at 160° C. for 3 hours, using an M-100DM injection molding machine manufactured by Meiki Seisakusho,
A preform was obtained by injection molding into a mold that had been cooled with cooling water at 10° C. at a cylinder temperature set at 300° C. This preform has a cylindrical body with an outer diameter of 22 to 24 mm.
, has a wall thickness of 3.5 mm, a total length of 175 mm, and has a bottomed end, and a density of 1.330 to 1.335 g/
It was a substantially amorphous, colorless and transparent molded product with a size of cm3.

[0038] This bottomed preform was stretched in the axial direction in a bottle-shaped mold at 95 to 110°C, and
/cm2 of nitrogen gas to laterally expand the body to have an outer diameter of 82 mm, a total height of 280 mm, and a body wall thickness of 280 to 350 mm.
A bottle with an internal volume of 1040 to 1050 ml was molded.

The hue was measured at four equal parts in the circumferential direction of the bottle body, that is, the center of the total height of the bottle. The results obtained are averaged and shown in Table 2.

[0040]

[Table 2]

Examples 5 and 6 and Comparative Examples 5 and 6 IV0.6
3 (poly 4,4'-dioxydiphenyl 2,2-propane carbonate) and polybutylene 2,6-naphthalate of IV 0.60, respectively.
It was dried with hot air at ℃ for 5 hours. Thereafter, it was fed into an extruder, extruded through a die into a film, and cast onto a cooling drum.

Next, the film was preheated with an infrared heater, and then formed into a box-shaped tray using a plug assist vacuum forming method.

[0043] The tray is 12.2 cm tall and 5.7 cm wide.
It was box-shaped with a depth of 2.2 cm and a depth of 2.2 cm, and the thickness of the side surface was measured at the center of each side and averaged. The results obtained are shown in Table 3.

[0044]

[Table 3]

Claims (5)

[Claims] Claim 1: The thermoplastic resin contains a thermoplastic resin with excellent transparency and a polyalkylene naphthalate resin, and the thermoplastic resin has a weight of 99.9% based on the total weight of both resins.
The polyalkylene naphthalate resin is more than 8% by weight and less than 99.98% by weight, and the polyalkylene naphthalate resin is more than 0.02% by weight and 0.
A film or sheet with excellent transparency and weather resistance, characterized by a content of less than 2% by weight. 2. The thermoplastic resin contains a highly transparent thermoplastic resin and a polyalkylene naphthalate resin, and the thermoplastic resin has a weight of 99.9% based on the total weight of both resins.
The polyalkylene naphthalate resin is more than 8% by weight and less than 99.98% by weight, and the polyalkylene naphthalate resin is more than 0.02% by weight and 0.
A hollow molded article having excellent transparency and weather resistance, characterized in that the content is less than 2% by weight. 3. The film or sheet according to claim 1, and the blow molded article according to claim 2, wherein the thermoplastic resin is polycarbonate. 4. The film or sheet according to claim 1, and the blow molded article according to claim 2, wherein the thermoplastic resin is polyethylene terephthalate. Claim 5: The polyalkylene naphthalate is polyethylene 2,6-naphthalate or/and polybutylene 2-naphthalate.
, 6-naphthalate, and the hollow molded article according to claim 2.