JPS619454A - Polyethylene terephthalate composition for stretch blow molding - Google Patents

Abstract

PURPOSE:The titled resin composition which is capable of producing hollow moldings having excellent gas barrier properties with good moldability without deteriorating the essential characteristics of the resin, prepared by incorporating a polyamide resin containing xylylene groups and mica powders into a polyethylene terephthalate resin. CONSTITUTION:100pts.wt. polyethylene terephthalate resin containing at least about 80mol% ethylene terephthalate units, 5-30pts.wt. polyamide resin containing xylylene groups (e.g. a copolymer of adipic acid and m-xylylenediamine), and 0.2-5pts.wt. mica powders of the particle diameter of about 2-100mum are compounded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a polyethylene terephthalate composition for stretch blow molding using a polyethylene terephthalate resin whose repeating units are mainly composed of ethylene terephthalate, and is suitable for use in various containers, etc. The present invention provides a polyethylene terephthalate composition that is used when obtaining a hollow molded body by a stretch blow molding method.

(Prior Art and Object of the Present Invention) A hollow body produced by stretch blow molding using polyethylene terephthalate resin has excellent mechanical properties.

It has excellent properties such as gas barrier properties, chemical resistance, fragrance retention, and non-toxicity, and is widely used as containers for various purposes. A polyethylene terephthalate composition containing a small amount of polyamide resin was proposed (Japanese Patent Application Laid-open No.
8-90033).

However, although the polyethylene terephthalate composition mixed with the xylylene group-containing polyamide resin produces a stretch-blow-molded product that satisfies the original purpose of gas barrier properties, this mixed resin has poor moldability. Because it has the effect of reducing the gas barrier properties, it is a negative factor in mass producing stretch-blow molded products with uniform container shape and wall thickness. When the polyamide resin is mixed with the polyethylene terephthalate resin in a high proportion of 10% by weight or more of the polyethylene terephthalate resin, the moldability deteriorates significantly.

For this reason, when taking full advantage of the improved gas barrier properties of xylylene group-containing polyamide resins, the range of selection of molding conditions becomes narrower, resulting in the disadvantage that molding conditions are subject to various regulations. Ru.

The present invention provides a stretch-blow molded article with a high degree of gas barrier property by adding a xylylene group-containing polyamide resin, and also prevents the decrease in stretch-blow moldability due to the addition of the xylylene group-containing polyamide resin. ,
This is compensated by adding and containing mica powder in the molding composition, and the moldability is good when molding a stretch blow molded product, and the stretch blow molded product is made of polyethylene terephthalate resin that does not contain additives. It can be molded at the same production speed as when obtaining molding, and there is no production of defective products due to molding difficulties.
The object of the present invention is to provide a polyethylene terephthalate resin molding composition that can be smoothly molded and yields a hollow body, which is a stretch blow molded body, and has a high degree of gas barrier property.

(Structure of the Invention) The polyethylene terephthalate composition for stretch blow molding of the present invention is a molding composition used when performing stretch blow molding using polyethylene terephthalate resin.
A closed or open cylindrical body with an opening, most commonly obtained by injection molding or extrusion.
2. Adjusting the stretching temperature of the parison, and simultaneously or sequentially stretching the parison in the axial direction with a stretching rod and in the circumferential direction with a compressed gas in a stretch blow molding mold.
) is a molding composition used for stretch blow molding, and the repeating unit is mainly composed of ethylene terephthalate! 5 to 3 xylylene group-containing polyamide resins per 100 parts of fat
0 parts by weight of mica powder and 02 to 50 parts by weight of mica powder fGVr, wherein the mica powder is 1+ of the xylylene group-containing polyamide resin,
O@Ek, more than % is added.

The polyethylene terephthalate resin in the polyethylene terephthalate composition for stretch blow molding of the present invention has repeating units mainly composed of ethylene terephthalate, and usually 80 mol% or more, preferably 90 mol% or more of the acid component is In terephthalic acid, 80 mol% or more, preferably 90 mol% or more of the glycol component is ethylene glyfur, and the remaining acid components include isophthalic acid, diphenol ether-4+ 4'-dicarboxylic acid, and naphthalene. I+- or? , 6-zocarboxylic acid, decane 1,1°-dicarboxylic acid, azopic acid, cepacic acid, hexahydrophthalic acid, etc., and the remaining glyfur components include propylene glycol, 1,
Ll--butanediol, neopentyl glycol, dielene glycol, 1,6-hexanediol, cyclohexane dimetatool, ? .

2-his(l+-hydroxyphenyl)propane, 2.
2-bis(4-hydroxyethoxydiphene: )Lr,
) '7' Ethylene terephthalate resin used in Rohan etc., ethylene terephthalate resin in which p-oxybenzoic acid or p-oxyethquin benzoic acid is copolymerized as a copolymerization component, or polyethylene terephthalate and copolymerized polyester. A blend resin in which repeating units of ethylene terephthalate account for 80 mol % or more is used.

The xylylene group-containing polyamide resin contained in the polyethylene terephthalate composition for stretch blow molding of the present invention provides a hollow body, which is a stretch blow molded product, molded with the polyethylene terephthalate composition of the present invention, with high gas barrier properties. However, when the mixing ratio of the xylylene group-containing polyamide resin to the polyethylene terephthalate resin is 5% by weight or more, the effect of adding the resin becomes clear, but when it exceeds 30% by weight, the Since there is a risk of producing defective products due to difficulty in molding, the mixing ratio of the xylylene group-containing polyamide resin to the polyethylene terephthalate resin is selected within the range of 5 to 30% by weight.

The mica powder added together with the xylylene group-containing polyamide resin in the polyethylene terephthalate composition for stretch blow molding of the present invention is intended to improve the stretch blow moldability that deteriorates due to the addition of the xylylene group-containing polyamide resin. Mica powder of about 2 to 100 microns is used. The components constituting this mica powder have the general formula: A(B,C) Do(OH,ii',0)22
~3 4 10 [In the formula, A.- is Na, Ca, B, 0.--Fel1.
Between Fe and Mn.

It is an alkali metal amine silicate represented by At, Mg, V% D='Si, At]. As mentioned above, this mica powder is blended to improve the stretch blow moldability of the polyethylene terephthalate composition of the present invention, so it is necessary to add the mica powder in an amount proportional to the amount of the xylylene group-containing polyamide resin to some extent. Its effect is fully expressed when the xylylene group-containing polyamide resin is added in an amount of 4.0% by weight or more. However, adding more mica powder than necessary is not only uneconomical but also causes a decrease in the gas barrier properties of the resulting hollow body, which is the stretch-blow molded product. It is necessary to keep it below.

In addition to the xylylene group-containing polyamide and mica powder, the polyethylene terephthalate composition for stretch blow molding of the present invention contains dyes and pigments to adjust the color tone of the resulting hollow body, as well as light-shielding properties. titanium dioxide powder, an antioxidant to provide antioxidant performance, a dispersant to make the composition uniform, and barium sulfate, calcium carbonate, and talc.

Of course, inorganic fillers such as zinc white can be added as appropriate. However, the blending of inorganic fillers is a factor that reduces the gas barrier properties of the hollow body that is generally obtained as a stretch blow molded product, and also deteriorates the stretch blow moldability of the composition. When the amount of the mica powder in the polyethylene terephthalate composition of the present invention is relatively large, it is preferable to avoid incorporating the inorganic filler. As described above, titanium dioxide powder can be contained in the polyethylene terephthalate composition of the present invention in order to provide the obtained hollow body with light-shielding properties. Titanium-coated mica powder can also be used as a combined substance with the mica powder, which is an essential component therein.

(Effect of the invention) The xylylene group-containing polyamide resin in the polyethylene terephthalate composition of the present invention provides a high degree of gas barrier property to the hollow body, which is a stretch-blow molded product obtained from the polyethylene terephthalate composition of the present invention. However, the suffocating effect of xylylene group-containing polyamide resin is 1. If the mixing ratio of the xylylene group-containing polyamide resin to the polyethylene terephthalate resin becomes too large, the wall structure of the hollow body will become a laminated foil structure, which will easily cause delamination between the layers of each consumption. The xylylene group-containing polyamide resin mixed into the polyethylene terephthalate resin is It acts to arrange the molecules of polyethylene terephthalate in a multilayer foil-like manner, and also strengthens the bonds between the polyethylene terephthalate molecules forming each layer.As a result, the wall structure of the hollow body resembles a multilayer structure, and the It is presumed that this material realizes the gas barrier properties of the material.

The mica powder, which is the other essential component in the polyethylene terephthalate composition of the present invention, improves the stretch blow moldability 5 which is deteriorated by the addition of the xylylene group-containing polyamide resin. This is to achieve the effect of increasing the stretching stress of the composition, and as a result, to equalize the wall thickness distribution etc. of the hollow body, which is the stretch-blow molded body obtained.

Hereinafter, the specific structure of the polyethylene terephthalate composition for stretch blow molding of the present invention will be shown in Examples, and the physical properties of a hollow body, which is a biaxially stretched blow molded product obtained using the composition, will be shown in Comparative Examples. This will be explained along with the physical properties of the hollow body made of the polyethylene terephthalate composition.

Examples/Comparative Examples (Part 1) 1 in which xylylene group-containing polyamide resin and mica powder were blended in the amount shown in the specified column of Table 1 below with respect to the i o o wit portion of polyethylene terephthalate resin.
Bottomed cylindrical parisons (body diameter: 3 mtn) obtained using three types of polyethylene terephthalate compositions for stretch blow molding.

After heating the total height 1361'l"l to a stretching temperature of 90 to 120°C, biaxial stretch blow molding is performed, and the average thickness of the body is approximately 0.
．． Machine-like hollow molded bodies (1) to (13), which are biaxially stretched blow molded bodies having a diameter of 55 mm and a volume of 1.5 t, were obtained.

The thickness variations, height variations, and gas barrier properties of each of the obtained hollow molded bodies are as shown in Table 1.

Examples/Comparative Examples (Part 2) Nine types of stretch blow molding in which xylylene group-containing polyamide resin and mica powder were blended in the amounts shown in the specified columns of Table 2 below with respect to 100 parts by weight of polyethylene terephthalate resin. A cylindrical parison with a bottom (body diameter: 3 f 3 m) obtained using a polyethylene terephthalate composition for
m.

After heating the 11-17 pieces (total height 11-17) to a stretching temperature of 90 to 120°C, biaxial stretch blow molding is performed, and the average thickness of the body is approximately 0.
A mechanical hollow molded body (sections 1 to (a)) which is a biaxially stretched blow molded body having a diameter of 55 mm and a capacity of 2.07 mm was obtained.

The thickness variations, height variations, and gas barrier properties of each of the obtained hollow molded bodies are as shown in Table 2.

Nao, in Tables 1 and 2 above, a copolymer of adipic acid and m-xylylene diamine was used as the xylylene group-containing polyamide resin.

In addition, the variation in wall thickness of the obtained hollow molded bodies was determined by measuring the wall thickness in four directions for each of five hollow molded bodies of each type, and finding the highest value among the values of 5 × 1 + - 20 points. and the minimum, and the height variation is the difference between each type of hollow molded body 10
It is expressed with a standard deviation of 0 lines.

(Effects of the Invention) The polyethylene terephthalate composition for stretch blow molding of the present invention has the composition as described above, and the stretch blow moldability of the composition is as follows. It has good blow moldability, and the hollow body that is a stretch blow molded product made of this composition has the same mechanical strength, chemical resistance, and hygiene as the hollow molded product made of polyethylene terephthalate resin that is not mixed with additives. It has excellent properties in terms of strength, lightness, etc., and has the effect of exhibiting extremely excellent properties in terms of gas barrier properties.

Claims (1)

[Claims] Polyethylene containing 5 to 30 parts by weight of a xylylene group-containing polyamide resin and 0.2 to 5.0 parts by weight of mica powder, based on 100 parts by weight of a polyethylene terephthalate resin whose repeating units are mainly composed of ethylene terephthalate. A polyethylene terephthalate composition for stretch blow molding, characterized in that the mica powder is added in an amount of 4.0% by weight or more of the xylylene group-containing polyamide resin.