JP2023119208A - Drawdown inhibitor for polyester resin - Google Patents

Abstract

To provide a drawdown inhibitor for polyester resin that is blended with polyester resin and can thus suppress drawdown during the molding of a polyester resin composition.SOLUTION: A drawdown inhibitor for polyester resin comprises pentaerythritol tetra fatty acid ester with contents of both metal elements Na and Sn being 2 mg/kg or less as an active ingredient.SELECTED DRAWING: None

Description

The present invention relates to a drawdown inhibitor to be blended with a polyester resin.

Conventionally, polyester resin has excellent transparency and is easy to punch, cut, bend, etc., so it is used as an external transparent material for containers such as food, cosmetics, medicine, blister packs for miscellaneous goods, clear cases, etc. Widely used.

However, the polyester resin has a low melt viscosity, and for example, it drips when coming out of the extruder in the extrusion molding process (hereinafter, the phenomenon that the polyester resin drips after being heated and kneaded is also referred to as "drawdown"), making it difficult to take it back. As a result, there is a problem that the productivity is lowered.

Techniques for suppressing the drawdown of polyester resin include amorphous polyester resin (I), containing two or more hydroxyl groups per molecule, having a weight average molecular weight of 200 or more and 500,000 or less, and (X) 20 to 99. A reactive compound ( II), and a multilayer structure polymer particle (III), a modifier for a polyester resin (Patent Document 1), an amorphous polyester resin (I), a glycidyl group and / or an isocyanate group A polyester resin modifier (Patent Document 2), etc., comprising a reactive compound (II) containing two or more per molecule and having a weight average molecular weight of 200 to 500,000, and a lubricant (III) is disclosed. It is However, these techniques have advantages and disadvantages, and an excellent drawdown inhibitor capable of sufficiently inhibiting the drawdown of polyester resins has been desired.

JP 2010-159431 A JP 2006-124451 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a drawdown inhibitor for a polyester resin, which can suppress drawdown during molding of the resin composition by being blended with the polyester resin.

The present inventors have made intensive studies to solve the above problems, and found that the above problems were solved by adding a pentaerythritol tetra-fatty acid ester containing a specific metal element to a polyester resin with a certain amount or less. I found a solution. Based on these findings, the present inventors have further studied and completed the present invention.
That is, the present invention
(1) A drawdown inhibitor for a polyester resin containing, as an active ingredient, a pentaerythritol tetra-fatty acid ester in which the contents of the metallic elements Na and Sn are respectively 2 mg/kg or less,
(2) a polyester resin composition containing the drawdown inhibitor of (1);
(3) a molded article obtained by molding the polyester resin composition of (2);
consists of
In addition, the present invention
(4) A method for suppressing drawdown of a polyester resin composition, which comprises blending the drawdown inhibitor of (1) with a polyester resin,
also includes

The drawdown inhibitor for polyester resin according to the present invention can suppress drawdown during molding of the polyester resin composition by blending with the polyester resin. In addition, the molded article obtained by molding the polyester resin composition containing the drawdown inhibitor for polyester resin according to the present invention is excellent in heat resistance and transparency. Furthermore, an anti-blocking agent can be added to the drawdown inhibitor for polyester resins according to the present invention.

Pentaerythritol tetra-fatty acid ester (hereinafter also referred to as "pentaerythritol tetra-fatty acid ester of the present invention") which is an active ingredient of the drawdown inhibitor for polyester resin according to the present invention (hereinafter also referred to as "drawdown inhibitor of the present invention") is a compound having four ester bonds in which fatty acids are ester-bonded to all four hydroxyl groups of pentaerythritol. It is produced by a method known per se such as reaction.

In the pentaerythritol tetrafatty acid ester of the present invention, the contents of the metallic elements Na and Sn are each 2 mg/kg or less, preferably 1 mg/kg or less. The method for measuring the content of the metal elements Na and Sn is not particularly limited, but for example, acid decomposition-inductively coupled plasma emission spectrometry using an ICP emission spectrometer (model: ICPE-9800; manufactured by Shimadzu Corporation). method (ICP-AES method).

The fatty acid constituting the pentaerythritol tetrafatty acid ester of the present invention is not particularly limited, and examples thereof include saturated fatty acids and unsaturated fatty acids having 8 to 22 carbon atoms. Specific examples include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, arachidic acid, behenic acid, and erucic acid. Among these, palmitic acid or stearic acid is preferred. Any one of these fatty acids may be used alone, or two or more thereof may be used in combination.

A method for producing the pentaerythritol tetrafatty acid ester of the present invention is not particularly limited, and a known method is employed. For example, the following method can be exemplified as a production method by an esterification reaction.
For example, pentaerythritol and fatty acid are charged into a normal reaction vessel equipped with a temperature controller, a stirrer, a heating jacket, a nitrogen inlet tube, a moisture metering tube, an air cooling tube, etc., and if necessary, a catalyst is added and stirred and mixed. , Under a nitrogen gas atmosphere, while removing water generated by the esterification reaction out of the system, heating at a predetermined temperature using a temperature controller to obtain a reactant (esterification product) that has undergone an esterification reaction. . Here, the molar ratio of the fatty acid charged is 3.5 to 4.5 mol, preferably 3.8 to 4.0 mol, per 1.0 mol of pentaerythritol. The reaction temperature is usually in the range of 190-250°C, preferably in the range of 210-240°C. Moreover, the reaction pressure condition may be under reduced pressure or under normal pressure. The end point of the reaction is usually determined by measuring the acid value of the reaction mixture, and the acid value is 1.5 or less, preferably 1.0 or less.

The catalyst used in the esterification reaction is not particularly limited, and examples include tin catalysts such as tin oxide, tin octoate, dibutyltin dilaurate, and dibutyltin oxide; Metal-based catalysts such as titanium catalysts and the like are included. Any one of these catalysts may be used alone, or two or more thereof may be used in combination. The amount of catalyst used is 0.01 to 1 part by mass, preferably 0.05 to 0.1 part by mass, based on 100 parts by mass of the total amount of pentaerythritol and fatty acid used.

When the contents of the metal elements Na and Sn in the reactant (pentaerythritol tetra-fatty acid ester) obtained by the esterification reaction exceed 2 mg/kg, respectively, a treatment for removing these metal elements is performed. Examples of methods for removing the metal elements Na and Sn include methods such as adsorbent treatment and neutralization treatment. As a specific example of the adsorbent treatment, for example, an adsorbent containing aluminum hydroxide, aluminum silicate, magnesium silicate, magnesium oxide, etc. is added to the reactant (pentaerythritol tetra-fatty acid ester) obtained by the esterification reaction. and then heating and mixing, followed by filtering to remove the adsorbent.

The amount of the adsorbent to be added is not particularly limited, but it is 0.1 to 5 parts by mass, preferably 0.2 to 2 parts by mass, based on 100 parts by mass of the reactant (pentaerythritol tetrafatty acid ester) obtained by the esterification reaction. part by mass. The treatment temperature for the adsorbent treatment is 70 to 100°C, preferably 80 to 90°C. The treatment time for the adsorbent treatment is preferably 0.5 to 3.0 hours.

In addition to the pentaerythritol tetra-fatty acid ester of the present invention, the drawdown inhibitor of the present invention may contain any additive as long as the effects of the present invention are not impaired. Examples of the additives include antiblocking agents, antistatic agents, plasticizers, stabilizers, lubricants, processability improvers, antioxidants, hydrolysis inhibitors, slip agents, pigments, fillers, flame retardants, and antifogging agents. agents and the like.

The anti-blocking agent is not particularly limited, and examples thereof include kaolin, silica, calcium carbonate, talc, etc. Kaolin is preferable from the viewpoint of transparency of the polyester resin composition.

The drawdown inhibitor of the present invention can suppress drawdown during molding such as extrusion molding by blending it with a polyester resin and using it. As a result, for example, effects such as an improvement in productivity are expected.

The polyester resin to be used for the drawdown inhibitor of the present invention is not particularly limited. etc. In addition, the polyester resin may be not only a homopolymer of one type of monomer, but also a copolymer of two or more types of monomers. Examples of the copolymer include glycol-modified polyethylene terephthalate, polybutylene terephthalate adipate, polybutylene succinate adipate, poly DL-lactic acid, and copolymers of polyethylene glycol adipate and poly L-lactic acid. In addition, polyhydric alcohols having a valence of 3 or higher such as glycerin and pentaerythritol, and polycarboxylic acids having a valence of 3 or higher such as trimetic acid may be added. A mixture of two or more polyester resins may also be used.

The blending amount of the drawdown inhibitor of the present invention in the polyester resin is 0.01 to 3.0 parts by mass, preferably 0.1 to 0.1, of the pentaerythritol tetrafatty acid ester of the present invention per 100 parts by mass of the polyester resin. It may be adjusted so that 0.9 parts by mass is blended.

There is no particular limitation on the method of blending the drawdown inhibitor of the present invention with the polyester resin, for example, (1) a method of melt-kneading the polyester resin and the drawdown inhibitor of the present invention, Examples include a method of preparing a masterbatch containing the drawdown inhibitor of the present invention and melt-kneading the masterbatch and a polyester resin.

As the melt-kneading method, a method known per se can be used, and examples thereof include a method using a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader, and the like. The heating temperature for melt-kneading is 200 to 300°C, preferably 210 to 280°C. A polyester resin composition containing the drawdown inhibitor of the present invention thus obtained is also one embodiment of the present invention.

The polyester resin composition containing the drawdown inhibitor of the present invention is further subjected to various molding means such as extrusion molding, injection molding, compression molding, sheet molding, blow molding, vacuum molding, etc. to obtain an arbitrary shape. Can be used as moldings. A molded article obtained in this manner is also one embodiment of the present invention. The obtained molded article can be used for applications such as containers for foods, cosmetics, medicines, etc., blister packs for miscellaneous goods, exterior transparent materials for clear cases, and the like.

The present invention is illustrated by the following examples, which are merely illustrative of the invention and are not intended to limit the invention.

≪Preparation of pentaerythritol tetrafatty acid ester≫
(1) Production Example 1
A four-necked flask equipped with a temperature controller, a stirrer, a heating jacket, a nitrogen inlet tube, a water content metering tube, and an air cooling tube was charged with 184.0 g of pentaerythritol (trade name: Pentalit TS; manufactured by Koei Chemical Co., Ltd.), stearic acid. (Trade name: stearic acid 300; containing 65% by mass of stearic acid and 35% by mass of palmitic acid; manufactured by Shin Nippon Rika Co., Ltd.) 1060.8 g and palmitic acid (trade name: palmitic acid 98; containing 98% by mass of palmitic acid; natural oleo Co., Ltd.) was added, and 0.8 g of tin oxide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added as a catalyst. Under a nitrogen stream, the reaction water was distilled off at 235°C, and the mixture was reacted under normal pressure until the acid value became 1.0 or less, and then cooled to 130°C. Then, 1.376 g of 85% phosphoric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added for neutralization, mixed for 30 minutes, and then cooled to 90°C. Aluminum hydroxide-based adsorbent (trade name: Kyoward 200; manufactured by Kyowa Chemical Industry Co., Ltd.) and aluminum silicate-based adsorbent (trade name: Kyoward 700; Kyowa Kagaku Kogyo Co., Ltd.) was added to each of them, and after stirring and mixing for 30 minutes, 1400 g of pentaerythritol tetrafatty acid ester was obtained by removing by filtration. The pentaerythritol tetra-fatty acid ester is cooled to room temperature, and the solidified pentaerythritol tetra-fatty acid ester is pulverized with a Wiley pulverizer (model: 1029J-BS; manufactured by Yoshida Seisakusho Co., Ltd.) to form a powdery pentaerythritol tetra-fatty acid ester (pentaerythritol tetra-fatty acid ester). Erythritol tetrafatty acid ester 1) was obtained.

(2) Production Example 2
A pentaerythritol tetra-fatty acid ester 2 was obtained in the same manner as in the production of pentaerythritol tetra-fatty acid ester 1, except that the metal element removal treatment was not performed. A specific manufacturing method is as follows.
Pentaerythritol (trade name: Pentalit TS; manufactured by Koei Chemical Co., Ltd.) 184.0 g, stearic acid (trade name: stearic acid 300; stearin 65% by mass of acid and 35% by mass of palmitic acid; manufactured by Shin Nippon Rika Co., Ltd.) 1060.8 g and 355.2 g of palmitic acid (trade name: palmitic acid 98; containing 98% by mass of palmitic acid; manufactured by Natural Oreo) were added. , 0.8 g of tin oxide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added as a catalyst. Under a nitrogen stream, the reaction water was distilled off at 235°C, and the mixture was reacted under normal pressure until the acid value became 1.0 or less, and then cooled to 130°C. Thereafter, 1.376 g of 85% phosphoric acid (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added for neutralization and mixed for 30 minutes to obtain 1400 g of pentaerythritol tetrafatty acid ester. The pentaerythritol tetra-fatty acid ester is cooled to room temperature, and the solidified pentaerythritol tetra-fatty acid ester is pulverized with a Wiley pulverizer (model: 1029J-BS; manufactured by Yoshida Seisakusho Co., Ltd.) to form a powdery pentaerythritol tetra-fatty acid ester (pentaerythritol tetra-fatty acid ester). Erythritol tetra-fatty acid ester 2) was obtained.

(3) Production Example 3
A pentaerythritol tetra-fatty acid ester 3 was obtained in the same manner as in the production of pentaerythritol tetra-fatty acid ester 1, except that the neutralization treatment and metal element removal treatment were not performed. A specific manufacturing method is as follows.
Pentaerythritol (trade name: Pentalit TS; manufactured by Koei Chemical Co., Ltd.) 184.0 g, stearic acid (trade name: stearic acid 300; stearin 65% by mass of acid and 35% by mass of palmitic acid; manufactured by Shin Nippon Rika Co., Ltd.) 1060.8 g and 355.2 g of palmitic acid (trade name: palmitic acid 98; containing 98% by mass of palmitic acid; manufactured by Natural Oreo) were added. , 0.8 g of tin oxide (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added as a catalyst. These were reacted under normal pressure at 235° C. under a nitrogen stream until the acid value became 1.0 or less while distilling off reaction water to obtain 1400 g of pentaerythritol tetra-fatty acid ester. The pentaerythritol tetra-fatty acid ester is cooled to room temperature, and the solidified pentaerythritol tetra-fatty acid ester is pulverized with a Wiley pulverizer (model: 1029J-BS; manufactured by Yoshida Seisakusho Co., Ltd.) to form a powdery pentaerythritol tetra-fatty acid ester (pentaerythritol tetra-fatty acid ester). Erythritol tetra-fatty acid ester 3) was obtained.

Table 1 shows the contents of the metallic elements Na and Sn in the obtained pentaerythritol tetrafatty acid esters 1 to 3. The content of the metal elements Na and Sn is measured by acid decomposition-inductively coupled plasma atomic emission spectrometry (ICP-AES method) using an ICP emission spectrometer (model: ICPE-9800; manufactured by Shimadzu Corporation). did.

≪Preparation of drawdown inhibitor≫
(1) Raw materials 1) Pentaerythritol tetrafatty acid ester 1-3
2) Kaolin (trade name: Insulite MC-6; manufactured by Mizusawa Chemical Industry Co., Ltd.)

(2) Blending of Drawdown Inhibitor Table 2 shows the blending amount of the drawdown inhibitor produced using the raw materials. Drawdown inhibitors 1 and 2 are examples of the present invention, and drawdown inhibitors 3 and 4 are comparative examples.

(3) Method for producing drawdown inhibitors For drawdown inhibitors 1, 3, and 4, raw materials shown in Table 2 were used as drawdown inhibitors. Drawdown inhibitor 2 was obtained by putting an equal amount of the raw materials shown in Table 2 in a plastic bag, holding it by hand, and mixing it uniformly for 30 seconds.

≪Drawdown suppression evaluation test of polyester resin composition≫
A polyester resin (trade name: EASTAR GN-001; glycol-modified polyethylene terephthalate; manufactured by EASTMAN) and any of drawdown inhibitors 1 to 4 are added in an amount 10 times the amount of the raw materials shown in Table 3, and equipped with a strand die. It is put into a twin-screw extruder [model: KZW15TW-45MG-NH (-700); manufactured by Technovel], melt-kneaded at 210 ° C. and extruded into strands, and the extruded polyester resin composition is cut with a pelletizer. to obtain pellets 1 to 5. The obtained pellets 1-5 were placed in a melt indexer (model: Melt Indexer G-02; manufactured by Toyo Seiki Seisakusho), and the melt index was measured as Test Groups 1-5. Table 4 shows the results. The melt index is defined in accordance with JIS-K6924-1 and means the number of grams of the polyester resin composition that flows out per unit time when measured under conditions of a temperature of 190° C., a load of 2160 g, and a time of 10 minutes. A lower melt index value indicates a higher melt viscosity, that is, it indicates that drawdown is less likely to occur (drawdown can be suppressed).

As is clear from the results in Table 4, the test groups 1 and 2 containing the drawdown inhibitors 1 and 2 of the present invention have a melt index compared to the test group 5 to which no drawdown inhibitor is added. was remarkably low, and the drawdown was suppressed. On the other hand, test groups 3 and 4 containing drawdown inhibitors 3 and 4, which are comparative examples of the present invention, had a lower degree of decrease in melt index than test group 5 in which no drawdown inhibitor was added, and the drawdown The inhibitory effect was insufficient.

<<Preparation of molded article of polyester resin composition>>
(1) Raw materials 1) Polyester resin (trade name: EASTAR; GN-001; glycol-modified polyethylene terephthalate; manufactured by EASTMAN)
2) Drawdown inhibitors 1 and 2

(2) Blending Table 5 shows the blending amounts of the pellets or films produced using the above raw materials. Pellets or films 1 and 2 are examples of the invention.

Ten times the amount of the raw materials shown in Table 5 was put into a twin-screw extruder [model: KZW15TW-45MG-NH (-700); manufactured by Technobel] equipped with a strand die, and melted and kneaded at 210 ° C. A strand was extruded and the extruded polyester resin composition was cut with a pelletizer to obtain pellets 1 and 2. After drying the obtained pellets at 70 ° C. for 12 hours using a gear oven (model: GPHH-201; manufactured by Espec Co., Ltd.), a single screw extruder equipped with a T die (model: 3S150; manufactured by Toyo Seiki Seisakusho). was melt-kneaded at 260° C. and extruded to obtain films 1 and 2 having a thickness of 50 μm.

≪Heat resistance, transparency and anti-blocking evaluation test of molded articles of polyester resin composition≫
(1) Heat resistance The obtained pellets 1 and 2 are heat-treated at 230 ° C. for 90 minutes using a gear oven (model: GPHH-201; manufactured by Espec Co., Ltd.), and the YI value before and after the heat treatment is measured with a spectrocolorimeter ( Model: SE7700; manufactured by Nippon Denshoku Industries Co., Ltd.), and the difference in YI value before and after heat treatment was calculated. Table 6 shows the results. In addition, when the numerical value is 2.00 or less, it indicates that the change in color tone due to heat treatment is small and the heat resistance is excellent.

(2) Transparency HAZE (%) of obtained films 1 and 2 was measured using a haze meter (model: NDH2000; manufactured by Nippon Denshoku Industries Co., Ltd.). Table 7 shows the results. In addition, when a numerical value is 3.00 or less, it shows that it is excellent in transparency.

(3) Anti-blocking property The static friction coefficient between the films 1 and 2 obtained was measured by a method based on the JIS-P8147 gradient method. Table 7 shows the results. In addition, when a numerical value is 0.30 or less, it shows that it is excellent in antiblocking property.

As is clear from the results in Table 6, Pellets 1 and 2 of Examples of the present invention had excellent heat resistance and were preferable as molded articles. Moreover, as is clear from the results in Table 7, the films 1 and 2 of Examples of the present invention had excellent transparency and were preferable as molded articles. Furthermore, the film 2 containing the drawdown inhibitor 2 was excellent in anti-blocking properties and was preferable as a molded product.

Claims (3)

A drawdown inhibitor for a polyester resin comprising, as an active ingredient, a pentaerythritol tetrafatty acid ester having a metal element Na content and a Sn content of 2 mg/kg or less, respectively. A polyester resin composition containing the drawdown inhibitor of claim 1. A molded article obtained by molding the polyester resin composition of claim 2 .